X . I
electronic transmission components discipline
Transmission line loudspeaker
Exploded-view diagram showing the IMF Reference Standard Professional
Monitor loudspeaker by renowned transmission line speaker pioneer
John Wright
(of IMF/TDL), from the 1970s. The complex shape of the transmission
line allowed a full frequency range of 17 Hz to "beyond audibility" and
sensitivity of 80 dB (specified as 96 dB at 1 metre for 40 watts with
pink noise). The inset photograph shows the assembled loudspeaker.
A
transmission line loudspeaker is a loudspeaker
enclosure design (
topology) that uses an
acoustic transmission line within the cabinet, compared to the simpler enclosures used by sealed (closed) or
ported (bass reflex) designs. Instead of reverberating in a fairly simple
damped enclosure, sound from the back of the
bass speaker
is directed into a long (generally folded) damped pathway within the
speaker enclosure, which allows far greater control and use of speaker
energy, and the resulting sound.
Inside a transmission line (TL) loudspeaker, is a (usually folded)
pathway into which the sound is directed. The pathway is often covered
with varying types and depths of absorbent material, and it may vary in
size or taper, and may be open or closed at its far end. Used correctly,
such a design ensures that undesired resonances and energies, which
would otherwise cause undesirable auditory effects, are instead
selectively absorbed or reduced ("
damped") due to the effects of the duct, or alternatively only emerge from the open end
in phase
with the sound radiated from the front of the driver, enhancing the
output level ("sensitivity") at low frequencies. The transmission line
acts as an
acoustic waveguide,
and the padding both reduces reflection and resonance, and also slows
the speed of sound within the cabinet to allow for better tuning.
Transmission line loudspeakers designs are more complex to implement,
making mass production difficult, but their advantages have led to
acclaim for a number of manufacturers such as
IMF,
TDL,
PMC,
KVART & BØLGE
and the like. As a rule, transmission line speakers tend to have
exceptionally high fidelity low frequency response far below that of a
typical speaker or
subwoofer, reaching into the
infrasonic
range (British company TDL's studio monitor range from the 1990s quoted
their frequency responses as starting from as low as 17 Hz depending
upon model with a sensitivity of 87 dB for 1 W @ 1 metre), without the
need for a separate enclosure or driver.
Acoustically, TL speakers roll off more slowly (less steeply) at low
frequencies, and they are thought to provide better driver control than
standard reflex cabinet designs, are less sensitive to positioning, and tend to create a very spacious
soundstage.
Modern TL speakers were described in a 2000 review as "match[ing]
reflex cabinet designs in every respect, but with an extra octave of
bass, lower LF distortion and a frequency balance which is more
independent of listening level".
Although more complex to design and tune, and not as easy to analyze
and calculate as other designs, the transmission line design is valued
by several smaller manufacturers, as it avoids many of the major
disadvantages of other loudspeaker designs. In particular, the basic
parameters and equations describing sealed and reflex designs are fairly
well understood, the range of options involved in a transmission line
design mean that the general design can be somewhat calculated but final
transmission line tuning requires considerable attention and is less
easy to automate.
Purpose and design overview
Low frequencies, which remain in phase, emerge from the vent which
essentially acts as a second driver. The advantage of this approach is
that the air pressure loading the main driver is maintained which
controls the driver over a wide frequency range and reduces distortion.
[The TL design] also produces higher
SPL [sensitivity or loudness] and lower
bass extension than ported or sealed box of similar size.
- PMC, TL speaker design company
I have an intuitive abhorrence of resonance enhancement to give a
loudspeaker more "kick" or apparent bass as they can sound
"single-noted". Yes you can pick out the bass rhythm but what about the
melody. What a transmission line gives in my experience is a much
smoother and more realistic bass quality.
- Steve Davey, former TNT Audio staff member/reviewer
A transmission line is used in loudspeaker design to reduce time,
phase, and resonance related distortions, and in many designs to gain
exceptional bass extension to the lower end of human hearing, and in
some cases the near-
infrasonic
(below 20 Hz). TDL's 1980s reference speaker range (now discontinued)
contained models with frequency ranges of 20 Hz upwards, down to 17 Hz
upwards, without needing a separate
subwoofer.
Irving M. Fried, an advocate of TL design, stated that:
- "I believe that speakers should preserve the integrity of the
signal waveform and the Audio Perfectionist Journal has presented a
great deal of information about the importance of time domain
performance in loudspeakers. I’m not the only one who appreciates time-
and phase-accurate speakers but I have been virtually the only advocate
to speak out in print in recent years. There’s a reason for that.
- It is difficult and costly to design and manufacture a time- and
phase-accurate speaker system. Few of today’s high-end loudspeakers are
time- and phase-accurate designs. The audio magazines need to appeal to a
broad spectrum of advertisers including many who make speaker systems
which are time incoherent. The magazines, and the reviewers who write
for them, have ignored or downplayed the issue of time- and
phase-accuracy in order to maximize advertising revenue. I am not alone
in recognizing this situation."
The transmission line (TL) is the theoretical ideal, and one of the
most complex constructions, with which to load a moving coil drive unit.
The most common and practical implementation is to fit a drive unit to
the end of a long duct that is usually open at the far end. In practice,
the duct is folded inside a conventional shaped cabinet, so that the
open end of the duct appears as a vent on the speaker cabinet. There are
many ways in which the duct can be folded and the line is often tapered
in crossection to avoid parallel internal surfaces that encourage
standing waves. Some speaker designs also use a spiral or elliptic
spiral shaped duct, usually with one speaker element in the front or two
speaker elements arranged one on each side of the cabinet. Depending
upon the drive unit, and quantity and various physical properties of
absorbent material, the amount of taper will be adjusted during the
design process to tune the duct to remove irregularities in its
response. The internal partitioning provides substantial bracing for the
entire structure, reducing cabinet flexing and colouration. The inside
faces of the duct or line, are treated with an absorbent material to
provide the correct termination with frequency to load the drive unit as
a TL. The enclosure behaves like an
infinite baffle, potentially absorbing most or all of the speaker unit's rear energies.
A theoretically perfect TL would absorb all frequencies entering the
line from the rear of the drive unit but remains theoretical, as it
would have to be infinitely long. The physical constraints of the real
world, demand that the length of the line must often be less than 4
meters before the cabinet becomes too large for any practical
applications, so not all the rear energy can be absorbed by the line. In
a realized TL, only the upper bass is TL loaded in the true sense of
the term (i.e. fully absorbed); the low bass is allowed to freely
radiate from the vent in the cabinet. The line therefore effectively
works as a low pass filter, another crossover point in fact, achieved
acoustically by the line and its absorbent filling. Below this
“crossover point” the low bass is loaded by the column of air formed by
the length of the line. The length is specified to reverse the phase of
the rear output of the drive unit as it exits the vent. This energy
combines with the output of the bass unit, extending its response and
effectively creating a second driver.
Essentially, the goal of the transmission line is to minimize
acoustical or mechanical impedance at frequencies corresponding to the
driver's fundamental free air resonance. This simultaneously reduces
stored energy in the driver's motion, reduces distortion, and critically
damps the driver by maximizing acoustic output (maximal acoustical
loading or coupling) at the terminus. This also minimizes the negative
effects of acoustic energy that would otherwise (as with a sealed
enclosure) be reflected back to the driver in a sealed cavity.
Transmission line loudspeakers employ this tube-like
resonant cavity, with the length set between 1/6 and 1/2 the
wavelength of the
fundamental resonant frequency
of the loudspeaker driver being used. The cross-sectional area of the
tube is typically comparable to the cross-sectional area of the driver's
radiating surface area. This cross section is typically tapered down to
approximately 1/4 of the starting area at the terminus or open end of
the line. While not all lines use a taper, the standard classical
transmission line employs a taper from 1/3 to 1/4 area (ratio of
terminus area to starting area directly behind driver). This taper
serves to dampen the buildup of standing waves within the line, which
can create sharp nulls in response at the terminus output at even
multiples of the driver's Fs.
In a transmission line speaker, the transmission line itself can be
open ("vented") or closed at the far end. Closed designs typically have
negligible acoustic output from the enclosure except from the driver,
while open ended designs exploit the low-pass filter effect of the line,
and the resultant low bass energy emerges to reinforce the output from
the driver at low frequencies. Well designed transmission line
enclosures have smooth
impedance curves, possibly from a lack of frequency-specific resonances, but can also have low efficiency if poorly designed.
One key advantage of transmission lines is their ability to conduct
the back wave behind the transducer more effectively away from it –
reducing the chance for reflected energy permeating back through the
diaphragm out of phase with the primary signal. Not all transmission
lines designs do this effectively. Most offset transmission line
speakers place a reflective wall fairly close behind the transducer
within the enclosure – posing a problem for internal reflections
emanating back through the transducer diaphragm. Older descriptions
explained the design in terms of "impedance mismatch", or pressure waves
"reflected" back into the enclosure; these descriptions are now
considered outdated and inaccurate as technically the transmission line
works through selective production of
standing waves and
constructive and
destructive interference (see below).
A second benefit is that the resulting music is
time coherent (i.e.,
in phase). Fried quoted in 2002, a listening test performed and reported in December 2000's
Hi-Fi News
(as he believed) in which a high-quality recording was obtained using
reputable but non-time-coherent loudspeakers and this recording was then
time phase corrected; an expert listening panel "voted unanimously for
the superior realism and accuracy of the time corrected output" for high
quality sound reproduction.
A transmission line speaker employs essentially, two distinct forms of
bass loading,
which historically and confusingly have been amalgamated in the TL
description. Separating the upper and lower bass analysis reveals why
such designs have so many potential advantages over reflex and infinite
baffle designs. The upper bass is completely absorbed by the line
allowing a clean and neutral response. The lower bass is extended
effortlessly and distortion is lowered by the line’s control over the
drive unit’s excursion. One of the exclusive benefits of a TL design is
its ability to produce very low frequencies even at low monitoring
levels – TL speakers can routinely produce full range sound usually
requiring a
subwoofer,
and do so to very high levels of accuracy. The main disadvantage of the
design is that it is more labor-intensive to create and
tune
a high quality and consistent transmission line, compared to building a
simple enclosure. A 2010 Hifi Avenue TL speaker review commented that
"One thing I have noticed about transmission line designs is that they
create a rather big
soundstage and seem to handle crescendoes with ease".
History of transmission line loudspeakers
Invention and early use
This image is actually an inverted folded horn. You can tell as the
throat is larger than near the port opening. A true Transmission Line
enclosure is the same width 'vent' throughout. .
The concept was innovated within acoustic enclosure design, and
originally termed an "acoustical labyrinth", by acoustic engineer and
later Director of Research Benjamin Olney, who developed the concept at
the
Stromberg-Carlson Telephone Co.
in the early 1930s while studying the effect of enclosure shape and
size on speaker output, including the effect of "extreme length in a box
baffle". A patent was filed in 1934. The design was used in their console radios beginning in 1936. A loudspeaker enclosure based on the concept was proposed in October 1965 by Dr A.R. Bailey and A.H. Radford in
Wireless World (p483-486) magazine.
The article postulated that energy from the rear of a driver unit could
be essentially absorbed, without damping the cone's motion or
superimposing internal reflections and resonance, so Bailey and Radford
reasoned that the rear wave could be channeled down a long pipe. If the
acoustic energy was absorbed, it would not be available to excite
resonances. A pipe of sufficient length could be tapered, and stuffed so
that the energy loss was almost complete, minimizing output from the
open end. No broad consensus on the ideal taper (expanding, uniform
cross-section, or contracting) has been established.
"Classic" era transmission line loudspeakers
- Source for much of this section: Loudspeakers: for music recording and reproduction (Newell & Holland, 2007)
The birth of the modern transmission line speaker design came about
in 1965 with the publication of A R Bailey’s article in Wireless World,
“A Non-resonant Loudspeaker Enclosure Design”,
detailing a working Transmission Line. Radford Audio took up this
innovative design and briefly manufactured the first commercial
Transmission Line loudspeaker. Although acknowledged as the father of
the Transmission Line, Bailey’s work drew on the work on labyrinth
design, dating back as early as the 1930s. His design, however, differed
significantly in the way in which he filled the cabinet with absorbent
materials. Bailey hit upon the idea of absorbing all the energy
generated by the bass unit inside the cabinet, providing an inert
platform for the drive unit to work from; unchecked, this energy
produces spurious resonances in the cabinet and its structure, adding
distortion to the original signal.
Shortly thereafter the design entered mainstream
Hi-Fi, through the works of
Irving M. "Bud" Fried in the United States, and a
British trio: John Hayes,
John Wright,
and David Brown. Dave D'Lugos describes the period that followed
(approx. 35 years until the start of the 21st Century) as a period when
the "classical designs" were created.
Fried was exposed during his time at
Harvard University to high fidelity audio reproduction, and later became an importer of audiophile items. Under the
trademark "IMF" (his initials), from 1961, he eventually became involved with many advancements in
audiophile
equipment: cartridges (IMF – London, IMF – Goldring), tone arms (SME,
Gould, Audio and Design), amplifiers (Quad, Custom Series), loudspeakers
(Lowther, Quad, Celestion, Bowers and Wilkins, Barker, etc.). In 1968 he met John Hayes and John Wright, who had already designed an award winning
tone arm in the UK and had brought along a transmission line speaker designed by
John Wright - described by Hayes as "fanatical regarding quality" - in order to promote and demonstrate the tone arm at a New York hifi
show. Irving unexpectedly received a number of orders for the unnamed
speaker, which he dubbed the "IMF".
The British pair, along with Hayes' colleague David Brown, agreed to
form a UK company to design and manufacture speakers which would be sold
by Irving in the United States. John Hayes later wrote that:
- Of course, Bud, had called it the IMF, and therefore, perhaps
mistakenly we registered IMF and formed an IMF company... At no time did
Bud Fried have any input on the designs. We sold him speakers and he
was the US Distributor... [...] Bud
Fried was never a Director or shareholder of IMF Electronics. IMF
electronics were the only company manufacturing the transmission line
speakers. The name IMF was adopted because Bud Fried had demonstrated
the first prototype speakers at the New York hi fi show, and because of
the publicity and the fact that he had used his name on the then unnamed
speakers, we stuck with the name which was a mistake on our part. It
was never his company. After our lawsuit he called his speakers Fried.
The relationship broke down acrimoniously when Irving began to make
his own, poorer quality speakers, also marketed as "IMF", and refused to
cease until a court agreed that the UK business had the right to the
trademark IMF for loudspeakers. Following the split, Irving in the USA (under the
brandname "Fried") and the three founders of IMF Electronics in the UK (via a
joint venture with driver manufacturer Elac under the name
TDL), both became well known in audiophile circles for many years as major advocates of transmission line speaker design. TDL closed after John Wright's gradual failing of health and death in 1999 from
cancer.
He was described in his 1999 obituary as "one of the most important
figures on the British hi-fi scene since the mid-1960s... best
remembered for his transmission-line loudspeaker designs". The brand was acquired by
Audio Partnerships (part of retailer group
Richer Sounds). Freid died six years later, in 2005.
21st century
In the early 21st century,
mathematical models
that seemed to approximate the behavior of real-world TL speakers and
cabinets, began to emerge. According to the website t-linespeakers.org,
this led to an understanding that what he termed the "classical"
speakers, designed largely by "trial and error", were a "good job" and
the best that was reasonably possible at those time, but that better
designs were now achievable based on modeled responses.
Design principles
Fig. 1 - Relationship between TL length and wavelength
Fig. 2 - Frequency response (magnitude) measurement of Drive unit & TL outputs
Phase inversion is achieved by selecting a length of line that is
equal to the quarter wavelength of the target lowest frequency. The
effect is illustrated in Fig. 1, which shows a hard boundary at one end
(the speaker) and the open-ended line vent at the other. The phase
relationship between the bass driver and vent is in phase in the pass
band until the frequency approaches the quarter wavelength, when the
relationship reaches 90 degrees as shown. However by this time the vent
is producing most of the output (Fig. 2). Because the line is operating
over several octaves with the drive unit, cone excursion is reduced,
providing higher SPL’s and lower distortion levels, compared with reflex
and infinite baffle designs.
The complex loading of the bass drive unit demands specific
Thiele-Small driver parameters
to realise the full benefits of a TL design. Most drive units in the
marketplace are developed for the more common reflex and infinite baffle
designs and are usually not suitable for TL loading. High efficiency
bass drivers with extended low frequency ability, are usually designed
to be extremely light and flexible, having very compliant suspensions.
Whilst performing well in a reflex design, these characteristics do not
match the demands of a TL design. The drive unit is effectively coupled
to a long column of air which has mass. This lowers the resonant
frequency of the drive unit, negating the need for a highly compliant
device. Furthermore, the column of air provides greater force on the
driver itself than a driver opening onto a large volume of air (in
simple terms it provides more resistance to the driver's attempt to move
it), so to control the movement of air requires an extremely rigid
cone, to avoid deformation and consequent distortion.
The introduction of the absorption materials reduces the velocity of
sound through the line, as discovered by Bailey in his original work. L
Bradbury published his extensive tests to determine this effect in an
AES Journal in 1976 his results agreed that heavily damped lines could reduce the
velocity of sound by as much as 50%, although 35% is typical in medium
damped lines. Bradbury’s tests were carried out using fibrous materials,
typically longhaired wool and glass fibre. These kinds of materials
however produce highly variable effects that are not consistently
repeatable for production purposes. They are also liable to produce
inconsistencies due to movement, climatic factors and effects over time.
High specification acoustic foams, developed by manufacturers such as
PMC, with similar characteristics to longhaired wool, provide repeatable
results for consistent production. The density of the polymer, the
diameter of the pores and the sculptured profiling are all specified to
provide the correct absorption for each speaker model. Quantity and
position of the foam is critical to engineer a low pass acoustic filter
that provides adequate attenuation of the upper bass frequencies, whilst
allowing an unimpeded path for the low bass frequencies.
Mathematical equations, modelling, and design process
- The external links
section of this article links to a number of resources that detail the
mathematical principles, models, and DIY calculations, as well as
extended practical design material, related to transmission line
speakers.
For most of the 20th century, transmission line design remained more of an art than a science, requiring much
trial and error.
Jon Risch states in an article on classic transmission line design,
that the hard part was finding the best stuffing density along the
line's length, because "the line stuffing affects both the total
apparent line length AND the total apparent box volume simultaneously".
He summarized the state of design at the time as:
- "The classic transmission line bass enclosure has never been completely and successfully modeled such that it can be built from a pat set of equations.
Some claim to have done this, but it doesn't seem to allow a first time
build without adjustments, so the models have enough wrong to require a
fudge factor..."
Dave D'Lugos, founder of fan site t-linespeakers.org, comments that
this reflects the "classical" designs from the 1960s until Risch's
writing, during which period "TL design was seat of the pants".
However from the 21st century, Martin King and George Augspurger
(both separately and referencing each other's works), produced models
which show these to be "generally less than optimal" designs which "did a
good job of approaching what was possible in their day". Audio engineer
Augspurger had modeled TL using an electrical analogy, and found it to
agree closely with King's existing work, based on a mechanical analogy.
D'Lugos concluded in his overview of TL modeling and design theory: "I
think that using modern drivers & tools such as King's software you
can build a better TL easier today".
Prominent individuals and companies
Pioneers:
-
- Benjamin Olney - originated the idea of a duct in speaker enclosure design, which he termed an "acoustic labyrinth", while working for Stromberg-Carlson as an acoustic engineer and studying the effect of enclosure size on output sound.
- Bailey and Radford - worked together and developed the concept for
loudspeakers (1965). Their design was a significant development from the
earlier work. Bailey's name was on the article and Radford built the
first commercial TL speaker.
- John Wright
together with business partner John Hayes and (later) David Brown, and
their company IMF Electronics Ltd (later: TDL) - Wright, a "fanatical"
pursuer of quality, had designed an award winning tone arm
and to demonstrate it, brought to New York a non-commercial TL speaker
he had also designed. The speaker gained considerable attention and
Wright, Hayes and colleage Brown formed a company that specialized in TL
speakers, and won numerous awards (1968). TDL disbanded following
Wright's death in 1999 and the brand - as a shell - was bought by Richer
Sounds.
- Irving M. "Bud" Fried
- American audiophile and TL advocate, who encountered Wright and Hayes
in 1968, recognized the potential of Wright's unnamed speaker, and
began marketing their TL speakers in the United States. Later set up a
TL company of his own to design speakers.
- Martin King and George Augspurger - researchers and designers who
succeeded in modeling realistic TL speaker designs in the early 21st
century.
X . II
Otomotif Transmission
automatic transmission ismeaning automatic transmission is, the notion of automatic transmission
Here is a brief definition of the word automatic transmission in automotive or motor engine.Automatic Transmission: Automatic transmission Meaning. Transmission or gearbox or automatic gear shift. If the car or the usual conventional transmission, the clutch works by shifting gears and then back on the gas. This automatic transmission then do not use the clutch. The driver only needs to step on the gas (such as when riding a boom-boom car). In a certain speed gear will switch itself off and the vehicle will keep going faster in accordance with the driver's gas pedal.This transmission system is suitable for Urban Vehicle or car in a city full of traffic jams. Because the driver will obviously not be exhausted because of holding the clutch. Some cars use this type of transmission, for example, Hyundai Atoz or Mercedes Benz A-Class. But many drivers prefer a manual transmission because of the 'pull' strength is more pronounced.
Automatic Transmission
This means that the automatic transmission. Transmission or gearbox or automatic gear shift. If the car or the usual conventional transmission, the clutch works by shifting gears and then back on the gas. This automatic transmission then do not use the clutch. The driver only needs to step on the gas (such as when riding a boom-boom car). In a certain speed gear will switch itself off and the vehicle will keep going faster conformed to the gas pedal of the driver. This transmission system is suitable for Urban Vehicle or car in a city full of traffic jams. Because the driver will obviously not be exhausted because of holding the clutch. Some cars use this type of transmission, for example, Hyundai Atoz or Mercedes Benz A-Class. But many drivers prefer a manual transmission because of the 'pull' strength is more pronounced
Automatic 4WDThis system moves with 2WD, until the system detects the need to use 4WD. Automatically power is divided into front and rear wheels in accordance with the ratio of field conditions. In general, the automatic system works when one of the tires slip. More modern, using software that can turn into a 4WD before wheel slip, by analyzing road conditions.
Anti-lock Braking System is useful to prevent locking effect on the brake pedal when the car suddenly so avoid the possibility of slippage due to the effects of pushing force vehicles away from the center point (centrifuges). The trick is to sensors that provide input or control, when to stop and when the wheels must spin the wheel. So when vehicle brakes, the wheels are not locked and the driver remains in control of the vehicle. This technology was first introduced by Daimler when it was still just a duet with Benz in 1970. ABS originally given the name of anti-block system created by Hans Scherenberg diStuttgart, Germany.
transmission
The transmission system
Speed shift lever (5 speed) at the Mazda Protege.Transmission
system, in automotive, is a system that works for the conversion of
torque and speed (revolutions) of the engine torque and speed be
different to be forwarded to the final drives. This conversion changed the high rotational speed becomes lower but more powerful, or vice versa.Example 5-speed transmission at 4,400 engine rpmGir gir RPM ratio numbers onexit shaft transmission1 3,769 1,1672 2.049 2.1473 1.457 3.0204 1,000 4,4005 0.838 5.251The
highest torque of an engine generally occurs around the middle of the
permitted engine speed limit, while vehicles requiring the highest
torque at the time began to move. In addition, vehicles running on roads that climb requires higher torque than a car that runs on a flat road. Vehicles that run at low speed requires higher torque than high speed. With the operating conditions vary, so it needed power transmission system so that needs can be met by the machine.
The manual transmission
Top and side view of a manual transmission that is placed on the floor of Ford with 4 speeds
The manual transmission is the type of transmission used in motor vehicles. This system uses a clutch operated by the driver to arrange the transfer of torque from the engine to the transmission, as well as the gear shift operated by hand (in the car) or legs (the motor). Gear acceleration assembled in the gear box / Reducer for some speed, typically ranging from 3 to 6 forward gear acceleration combined with one reverse gear (R). Gear acceleration is used depends on the speed of the vehicle at low speeds or uphill used gear acceleration 1 and so that the higher the speed, and vice versa if decelerate unloaded gear acceleration, braking can be assisted with a reduction gear acceleration.
Top and side view of a manual transmission that is placed on the floor of Ford with 4 speeds
synchromesh
Is a synchromesh transmission equipment which serves to equalize the rotation between the teeth to be connected so that the acceleration gear shifting can be done seamlessly. How it works when the transmission lever in neutral position, the synchromesh is in the middle does not affect or be affected by both the gear by his side.
Composition of gear acceleration
5-speed transmission lever in the Mazda Protege.
The arrangement / layout gear manual gearbox depending on the characteristics of commonly used sector in the region, Asia is somewhat different car output with Europe, especially in the placement of reverse gear (R). Placements are widely used transmission lever is on the floor but some modern cars use the transmission lever on the dashboard or old cars placed on the handlebars steering wheel.
5-speed transmission lever in the Mazda Protege.
Transmission lever floor
pattern explanation
manual Layout.svg
It is a 5-speed gear arrangement commonly used in modern cars plus one reverse gear marked with R. Placement reverse gear (R) is crucial because it can enter an interference with the vehicle, because if the teeth 5 wrong move could prove fatal to retreat ,
manual Dogleg.svg
This arrangement is an arrangement of five-speed gear commonly used in lightweight bus plus one reverse gear marked with R. Dental 1 is rarely used, is used when climbing on steep climbs.
the gear lever on the steering wheel
The gear lever on the steering Saab96
pattern explanation
Manual Layout Layout 3.svg car with three forward gears which is an arrangement of gear acceleration output American cars of the 1930s until the 1950s that at the time dubbed "three on the three"
Column4MT.svg is a layout that was developed after that, which was also developed by the output of cars of Europe and Japan. Until it is still used in some commercial cars such as the Mitsubishi L 300. 
Motorcycle gear lever
Suzuki SV650S acceleration gear lever.
Corak exchange motorcycle gear acceleration that are commonly used:
6
5 ┘
4 ┘
3 ┘
2 ┘
N
1
Acceleration gear lever with his left foot stepped on to get into first gear and prying upwards to get into gear 2, 3, and so on. If you want to lower the speed, the acceleration gear lever stepped down from 5 to 4 to 3 and so on. 
Advantages and BenefitsFuel consumption
The
manual transmission (M / T) connecting the engine to the transmission
with clutch-rigid compared with a torque converter in the automatic
transmission (A / T) or v-belt in the continuously variable transmission
(CVT). The manual transmission also does not waste energy because there is no hydraulic pump as the transmission of A / T. Therefore, the car with the transmission M / T is generally more efficient than the A / T or CVT; even
so the difference in fuel consumption has been somewhat reduced due to
the emergence of locking torque converter on the transmission of A / T. The
difference in fuel consumption between the M / T and A / T approximation
5-15% depending on the way of driving and road conditions. Next, the transmission M / T also does not require active cooling and
for mechanical simpler than A / T, then the weight is lighter than the
car with the transmission of A / T. Durability and maintenance feeendurance
Transmission M / T has a simpler mechanical system with parts less than A / T. Therefore, the treatment was generally easier and cheaper. In addition, the transmission M / T does not have any electrical
components, pumps, and cooling mechanisms such as the transmission of A /
T.The cost of care
The cost of vehicle maintenance manual are generally cheaper than the automatic. The new price of the vehicle manual also cheaper than the automatic.lubrication
Most transmission M / T depending on the splash lubrication despite some gearbox Rover also has an oil pump.Performance and Control
Transmission M / T is generally a greater number of gear ratios (gear ratio). Most vehicles have 5 to 6 speed manual gear, while transmitting A / T is usually only four teeth. Number of teeth which will further streamline the more fuel consumption.Braking engine (Engine Brake)Transmission A / T does not have an effective engine braking. This means that the machine is not effectively slows the car when the driver took off control speed. This causes the driver will use a lot of brakes, so the brake on the car A / T will wear faster.
automatic transmission
Pieces automatic transmission
Dental automatic planetary transmission.
The automatic transmission is the transmission to shift gears automatically accelerated. To change the rate of speed in the automatic transmission system is used the mechanism of friction and automatic transmission oil pressure. In the automatic transmission planetary gear serves to change the rate of speed and torque as well as on the gear manual transmission.
The tendency of people to use the automatic transmission has increased in recent years, particularly for luxury cars, and even certain types are already fully automatic transmission. the trend same was true on a motorcycle like Yamaha Mio, Honda Vario.
Pieces automatic transmission
Dental automatic planetary transmission.
Transmission DCT (Dual Clutch Transmission) Honda
Mode automatic transmissionTransmission DCT (Dual Clutch Transmission) Honda
The automatic transmission is controlled by simply moving the lever acceleration to a particular position. The
position of the automatic transmission lever are sorted by the format
of the P-R-N-D-3-2-L, as there are from left to right or from top to
bottom. Machines can only be switched on in the position P or N only.
Generally, the automatic transmission mode is as follows:
P (Park) is a position for parking the vehicle, Transmission locked in this position so that the vehicle can not be driven.
R (Reverse) is a position to reverse the vehicle.
N (Neutral) is a neutral gear position, engine relationship with the wheels in the free state.
D (Drive) is a position to go forward under normal conditions.
2 / S (Second) is a position to move forward on mountainous terrain.
1 / L (Low) is an advanced position on the gear shift to one, only used when driving on extremely steep terrain.
While optional is:
3 is a position to go forward and the transmission will not switch on the top gear position.
O / D (Over Drive) is the position of the transmission gear so that the displacement occurs at higher engine speed.
Varian AT
4A
/ T is the transmission variant A / T that is often encountered in many
mobil.Teknologi 4A / T is long enough to be present at
Indonesia.Digunakan car era 70's until now. Cars
that use this system include: Toyota Kijang LGX Krista 4AT and 4AT,
Honda CR-V, Honda Fit / Honda Jazz, Toyota Crown, Toyota Camry, Toyota
Corolla Altis, Toyota Corona, Honda Civic, dsb.4A / T using the format PRNDS / 2-L / 1 (without transmission D3 / 3 and without O / D).
5A / T. Not
much different from the transmission 4A / T, only format that
different.If format 4A / T is PRNDS / 2-L / 1, the 5A / T has
PRND-format D3 (or) O / D-2-1.5A / T is used the car of the year 1990'an until now (rare car using 5A / T before
the era of 90s they still wear 4A / T), among others: Suzuki Grand
Vitara, Honda Brio, Honda Freed, Honda Fit / Honda Jazz, etc.
CVT automatic transmission on a motorcycle matic
CVT
is the power transmission system from the engine to the rear tire using
a belt connecting the drive pulley to the driven pulley. Automatic
transmission is generally used in a scooter-type motorcycle (scooter),
although it is starting to be applied also to the cub-type motorcycle. Automatic transmission is an automatic transmission used "V" Belt, known as the CVT (Continuous Variable Transmission). CVT no longer use the gears to set a transmission ratio, but uses a
belt (V-Belt) and Vully to obtain variable gear ratio that varies.
construction CVT
The basic construction CVT pulleys based variable that the mechanical work consists of three main components:
Belts (V Belt) of rubber material
Primary pulley (drive pulley)
Secondary pulley (driven pulley)
Construction
CVT pulley consists of fruit two variable positioned at a certain
distance and both are connected by a belt (V Belt). Each pulley consists of two parts cone-shaped rear section attached to each other. Pulleys
used in so-called CVT pulleys variable , where one of the pulleys can be
moved closer or away from the other parts of the pulleys. This
is due to both components of the pulleys are centrifugal with a spring
mechanism that regulates the shift inverting each piece pulley
continuously by the high and low spin machine. A V-shaped belt made of rubber material installed in the center pulleys to connect the two pulleys. Belt inner side is made of jagged, with the aim to improve the ability of the contact (grip) on the belt pulleys.
Primary
pulley (drive pulley) to direct connected with a motorcycle engine and
driven pulley (secondary pulley) is connected to the rear wheel via the
intermediary drive mechanism in the form of centrifugal clutch and a
reduction gear. Belts are used to connect the power play from the drive pulley to the driven pulley.How CVT works
When Round Stationary Engines
In
the stationary rotation, centrifugal force that occurs in a string of
shoe centrifugal clutch unit has not been able to beat the centrifugal
spring tension. Shoes are not able to play the home friction clutch, so that the centrifugal clutch is not working. Engine torque which has been forwarded by stopping transmission on
centrifugal clutch unit so as to wheel and motorcycles are not running.
When Round Raised Engineering / Motorcycles On the Road
When
the engine rotation increases of approximately 3000 rpm, centrifugal
force that occurs in the friction shoe is already quite large. Friction shoe will be thrown out and the house scraped clutch. In these vehicles centrifugal clutch begin forwarding to wheel rear engine torque so that the motorcycle starts. while
the centrifugal force received a ballast roller on the drive pulley is
not sufficient to overcome the spring tension on the driven pulley. This causes the driven pulley tightens (the output is a large diameter). Because the length of the belt fixed, then the drive pulley will adjust to be in a position to widen, (small diameter). Large transmission ratio so as to produce a comparison round lightweight and large torque.
When High Speed Machine
At
the time of the engine rev up to medium speed, centrifugal force
received a ballast roller on the drive pulley is large enough, so that
the roller was thrown out, pressing pulley sliding on the drive pulley
to move towards narrowing and drive belt drive pulley diameter gets
larger. The length of the belt so that the belt stays on the driven pulley to a position that is wider (smaller diameter). This situation makes the transmission ratio decreases so that the rate increases the speed of the motorcycle.
When Round-Speed Machine
If
the machine reaches high speed, the centrifugal force received a
ballast roller on the drive pulley semangkin powerful that the outer
roller thrown kesisi, strong semangkin pressing pulley sliding on the
drive pulley to move towards narrowing and drive belt to the drive
pulley diameter greatest. Pull
the belt on the driven pulley will be even greater, pressing the driven
pulley spring to shift the drive pulley to the widest position
(smallest diameter). This situation makes the transmission ratio is getting smaller so that the rate is the higher the speed of the motorcycle.
When Motorcycles Carrying Heavy Load, accelerating or Streets Uphill
At
the time of a motorcycle carrying a heavy load, or accelerate quickly
when walking uphill, it takes a large torque so that the motorcycle can
keep going. Conditions
often encountered in this situation is the motorcycle was driving at
low speeds, but this time it takes a large torque. Usually
the driver will try to increase the torque produced by the engine by
opening the valve wide open so that the engine turns up and produces
great torque. In the CVT that works automatically by setting the engine rotation, this will be an obstacle. Normally,
when the engine rotation is increased, then the transmission ratio will
decline so this would be troublesome because the torque produced would
be reduced. Therefore, to overcome this difficulty, the CVT is equipped with a device called a kick down mechanisme. Construction of the kick down mechanism located on the driven pulley,
consisting of grooves made on a sliding pulli and nok / cam torque
invested in fixed pulleys. At the time of the rear wheel gain custody street .
Semi-automatic transmission
Ferrari F430 steering wheel incorporates acceleration gear shifting
Semi-automatic
transmission is a transmission that acceleration without touching the
gearshift / depress the clutch, the system uses electronic sensors,
processors and actuators to move the gear acceleration on the orders of
the driver. This system was developed to anticipate traffic congestion in urban areas. Semi-automatic transmission is also used in luxury sports cars such as
used Porsche, Maserati, Ferrari is sometimes placed on the steering
wheel to ease the switch gear acceleration.other applications
Motorcycle circulating in Indonesia in the early 1970s up to now
generally use semi-automatic transmission that is simple, moped very
popular at that time have only recently started to be produced and
marketed motorcycle automatic transmission as used on Yamaha Mio, Honda
Vario.Trade name semi automatic transmission
Ferrari F430 steering wheel incorporates acceleration gear shifting
Quickshift - Renault
2-tronic - Peugeot
Allshift, Twin Clutch SST - Mitsubishi
C-Matic - Citroën (Citroën CX and Citroën GS)
Easytronic - Opel
Durashift EST - Ford
Dualogic - Fiat
MultiMode, SMT (Semi Manual Transmission) - Toyota
I-SHIFT - Honda
Senso Drive or EGS or BMP - Citroën
Speed Gear - Fiat
Selespeed - Alfa Romeo, Fiat
Softouch - Smart
Sportronic - Mitsubishi
Duo Select - Maserati
Automatic Stickshift - Volkswagen
Sequentronic - Mercedes-Benz
SMG / SSG - BMW
S-Tronic - Audi
DSG (Direct Shift Gearbox) - Seat, Škoda, Volkswagen
DCT - Volkswagen, Bugatti, Koenigsegg
PDK (Porsche Doppelkupplungen) - Porsche
AMT (Automated Manual Transmission) - Proton
Main component
Clutch (clutch) or torque converter. Clutch is used for manual and semi-automatic transmissions and automatic transmission, the torque converter is used in the automatic transmission.
Transmission, also known as the gears.
Clutch / Torque converter
The clutch is a device used to connect two shafts at both ends for the purpose of transmitting mechanical power. Clutch normally does not allow the separation between the two shaft when operating, but at this time there is a clutch torque that is limited so that it can slip or disconnect when the torque limit is passed.
Coupling two rotating shafts
The main purpose of the clutch is to unite the two parts which can rotate. With the selection, installation, and maintenance is meticulous, clutch performance to the maximum, minimum power loss can be, and maintenance costs can be reduced.
Coupling two rotating shafts
benefit
Clutch used in machinery for various purposes:
To connect two units shaft made separately, such as the motor shaft with a wheel or shaft generator to the engine. The clutch is able to separate and connect the two shafts to the needs of repair and replacement of components.
To obtain mechanical flexibility, especially on the two shafts that are not on one axis.
To reduce shock loads (shock load) from one shaft to another shaft.
To avoid excessive workload.
To reduce the vibration characteristics of the two rotating shafts.
Clutch typeRigid couplings
Rigid
coupling is a coupling unit that brings together two types of shafts
which does not allow a change in position of the second shaft or
released, intentionally or unintentionally, when in operation. Rigid coupling is the right choice when second shaft want to be associated with the setting position is stable and precision. This clutch is a clutch with the highest service life for limitation
of torque, RPM, and the weight of the shaft and the clutch is not
exceeded .flexible couplingBeam couplings with threaded part helix Rzeppa joint and ...... Double Cardan Joint which is an example of a clutch CV
Coupling beam with its helical threaded part
Clutch gearOldham couplingsuniversal joint
Flexible
coupling is used when there is little change in the second shaft
axially position, radial, and angular when the engine is operating. Some types of flexible couplings, namely:
Beam
Clutch CV (constant-velocity)
diaphragm
disc coupling
Fluid coupling
Clutch gear (gear coupling)
Hirth joint
Oldham
Rag joint
universal joint
Coupling
beam, or it could be called a helical coupling, is delivering power
coupling between the two shafts to allow the change of position of the
shaft in angular, axial and parallel to a limited extent, when the shaft
work. The
design of the coupling beam is a clutch that has an empty section along
the body of helical or spiral-shaped coupling, thus making it flexible.
Coupling beam is usually made of aluminum alloy, stainless steel, and titanium.
Gear coupling is a clutch that transmits power between two shafts which are not in one line. The second shaft is connected to the third shaft in the clutch so-called spindle.
CV clutch is a clutch that allows for transmitting power at varying angles and at a constant rotational speed. Clutches of this type commonly used in automobile front wheel drive and all-wheel drive.
Universal
joint is the type of coupling in the form of two rigid bars that allow
the deflection of the direction of power transmission from the power
source. Uniersal hinge joint consists of a pair of adjacent and connected to the cross shaft. Universal
joint, though it transmits power which is not in line, but has a
drawback, which can provide output RPM is not constant despite constant
RPM input. It can cause vibration and wear on engine components.
Rzeppa joint and ...
, Double Cardan Joint which is an example of a clutch CV
Clutch gear
Oldham couplings
Universal joint
Gearboxes / transmision
Bristol 171 Sycamore helicopter gears
Gear is the gear and hydraulic system that delivers mechanical power from the drive to the wheels with lower speed but higher turning force. This system also allows the change of speed-power ratio or the direction of rotation.
In the car, known as manual and automatic transmission. Manual means the rider to change gears with the help of the stalk. This system is cheaper, lighter, typically have better performance, and consume less fuel. Automatic transmission easier to use and are usually found in the car of US products. There was also a semi-automatic gearbox system, ie when replacement gear shaft is driven by a computer.
Bristol 171 Sycamore helicopter gears
X . III
building transmission
X . IIII
transmission on a bike / bicycles
Automatic Bicycle
Many of us think about motorized or
electric powered bicycles when we hear the words
automatic bicycle,
but that is not what these bicycles are at all: An automatic bicycle is
a bicycle with automatic transmission, that shifts gears automatically
for the rider. With an automatic transmission, all of the gear
guess-work and thinking is done for you, according to your speed and
terrain.
The “Nuts and Bolts” of Automatic Bicycles
Automatic bikes are complex machines. The front hub of the bicycle is
fitted with a gauge to determine wheel revolution. This information is
sent to a computer chip housed near the pedals.
The computer chip controls the gears located on the rear tire hub and
determines whether to shift up or down, depending on how many times the
wheel revolves.
Throughout each bicycle ride, the sensors constantly search for the
desired gear, or the gear which will allow the rider to maintain his or
her preferred cadence.
Some bicycles with automatic transmission allow the rider to choose a
preferred cadence by pressing up and down buttons. When a desired
cadence has been chosen, the computer chip will constantly and
automatically shift the bike’s gears to stay in that cadence, taking out
all of the guesswork on the rider’s part.
Why Make an Automatic Bicycle?
Industry leaders who worked to develop the automatic transmission
felt the biking industry fell into a slump after the 1980’s and 90’s
when mountain biking and road racing became very popular.
Did you know...?
Did you know that bicycles with smartphone-controlled automatic transmissions have been developed?
Shimano, a leading bicycle manufacturer, unveiled a bicycle that
could be controlled using an iPhone app. The app detects the rider's
cadence using sophisticated wheel sensors and adjusts the gears
accordingly by streaming data from the iPhone to the transmission system
using Bluetooth technology.
Sales began to fall flat, so
bicycle manufacturers began tapping new technologies, which could be applied to biking.
Surveys conducted by Shimano, one of the leading experts in the
automatic bicycle industry, showed Americans felt bicycling was becoming
too elitist.
Many non-expert bikers felt the sport was too difficult and complex
to even attempt, and many riders didn't want to ride for fitness or
competition, they just wanted to ride for fun.
This desire led to the bicycle with automatic transmission, so all of
the complication and guesswork was taken out of biking, allowing the
rider to take up biking again in a carefree, fun way.
Is the Automatic Bicycle For You?
Bicycle automatic shifting is not intended for everyone, nor is
intended for all biking situations. They are not high-performance
vehicles for
road racing and for
mountain biking. They shouldn't even be used in inclement weather.
An automatic bicycle transmission is best for people who want casual
use out of his or her bicycle for social riding around town and riding
just for fun.
If you loved biking as a kid, and you are interested in taking up
biking again just for fun, bicycle with automatic transmission may be
just the thing for you. This is also the case if you want to bike simply
for the joy of cycling, and you're not interested in racing,
competition or any type of
extreme biking.
A bicycle with automatic transmission is a simple, fun way, to
reenter the world of cycling if you have been away, or a great bike for
leisure rides with the family or friends when you want a break from more
competitive, hard-core cycling.
When I first learned to drive, I learned on a car with a manual
transmission. It never seemed especially difficult because that was what
I got used to. In fact, the first time I had to drive an automatic, I
remember being very confused. What was I supposed to do with my left
foot? Do I not have to shift
at all? And if it’s automatic,
then what’s with all these different choices on the gearshift lever? I
quickly got the idea, of course, but still preferred the increased
control and responsiveness I got from making my own decisions about when
to shift. It would therefore seem that I should have the same attitude
about bicycles, which not only require manual shifting but typically
have many more than four or five gears. But manual bicycle transmissions
have always given me trouble, and I’ve frequently wished I could have
the convenience of an automatic transmission on a multi-speed bike.
Gearing Up for a Change
Sure enough, automatic bicycle transmissions have been in development
for almost 30 years, though only recently have they become commercially
available. Mechanically, the main thing needed for an automatic bike
transmission is a motor or piston that moves the chain between gears in
place of the standard lever-operated cable. This is a relatively
straightforward engineering problem, but the difficult thing is working
out how and when to tell the gears to shift. That computation currently
requires the use of a tiny, battery-operated computer along with sensors
that determine the current gear and the speeds at which wheels, pedals,
and sprockets are moving. The computer constantly recalculates the
optimal combination of front and rear gears to keep the rider at a
consistent pedaling cadence, automatically signaling the gears to shift
lower when going uphill or higher when going downhill. Using a
controller on the handlebars, riders can, if they wish, adjust the
gearing to provide a more intense workout or a gentler ride; they can
also override the automatic shifting entirely and use it as a
power-assisted manual transmission.
The first automatic bicycle transmission was designed by the Browning
family, whose main claim to fame had been gun design. Now an
independent company based near Seattle, Browning Components, Inc.
focuses solely on bicycles and bike transmissions. Their most
interesting innovation is a special gear with a hinged section (somewhat
like a pizza slice) that swings in and out to guide the chain from one
gear to the next. What’s great about the Browning mechanism is that the
chain remains engaged in sprockets at all times, rather than simply
dropping onto the next gear. This virtually eliminates the possibility
of the chain slipping, and also makes it possible to shift smoothly and
almost silently regardless of speed or load. Browning manufactures their
own bikes (whose frames must be custom designed to accept the special
transmission) and also supplies the transmission mechanism to other bike
manufacturers.
Shifting More Than Gears
Shimano, the largest manufacturer of bicycle components such as brakes
and shifters, has also begun selling automatic transmissions. One design
uses a seven-speed, internally geared hub; another, which is not yet
available in North America, uses a power-assisted derailleur system, but
adds an automatic, powered suspension to adjust the comfort of the ride
to fit current conditions. Bikes with the Shimano mechanism are
significantly heavier and more expensive than their manual counterparts
and are designed more for leisure riding than racing or mountain biking.
The Browning mechanism, on the other hand, was first employed on bikes
used for BMX racing, and adds somewhat less to the cost and weight of a
bike.
Adding an automatic transmission to a bicycle seems—in the abstract
at least—like a wonderful step forward in user interface. It replaces
something awkward with something invisible, which is the way good
technology should be. Whether or not the reality lives up to the hype
(or will in the future), I don’t know. And something tells me it ought
to be possible to create a purely mechanical automatic bike
transmission. I’m not sure what happens to an electronic one when the
batteries inevitably die; presumably it just stays in whatever gear it
was last set to.
At this point, automatic bike transmissions are not taken very
seriously among cycling enthusiasts. Some are put off by the extra
weight; some feel it’s not worth the money just to avoid having to move a
lever; and some just think automatic transmissions are for wimps.
FLASH BACK KNOW HOW THE BICYCLE ?
Bike. Transport equipment and exercise is still being conserved until now. The technology continues to evolve. From that time are still modest, has now become more complicated, and into many types, according to the needs of the wearer. Even so, the system remains essentially the same. Anyway, the bike is moving stick with stroke. How does the system work bike, consider the following.
Simply put, the power stroke of the foot moves forward gear. Front gear connected to the rear gear with the chain. Because interconnected, front gear when rotated the rear gear will also rotate and rotate the rear wheels.
If you notice, there is a bike that feels heavy or light when pedaled. Bike and rider weight affect this. But not only that. Another factor affecting among other things the number of gear ratio
between front and rear gear, wheel size, the width of the tire tread,
and the friction between moving parts.
Simply put, if the friction and weight of the bike is equated, it will get the following conclusions:- The weight of the bike pedaling the higher speed can be achieved. (Front gear ratios - the back is big enough)- The mild stroke bike, the lower the speed that can be achieved. (Front gear ratios - the back is quite small)
This conclusion is not absolute, because it depends on the strength of the stroke and the habits of each cyclist.
Factors heavy strokes:
The weight of the heavy bike
Fairly large front gear (number of teeth a lot)
The rear gear is quite small (number of teeth a little)
Large diameter rear wheels
Tire tread width
Friction large components
The sitting position is too low
Factors stroke feels light:
The weight of the bike light
Front gear small enough
The rear gear large enough
Small diameter rear wheel
Narrow tire tread
Minimal friction components
Optimal sitting position
The weight of the bike depends on the type of bike. Bicycles for competition is made possible se-light with enough force, in order to go fast. The bikes that we used to wear, made to be strong and durable at an affordable price, so it is relatively heavier.
Gear ratio has been no problem for the modern bicycle. Because it is equipped with a multi-speed gear shift, which we can use as needed. For bikes with a single gear, the gear can be removed and replaced with a size deemed more fitting.
The wheel also depends on the type of bike. Bike racing has a large diameter in order to go fast. MTB wheel size is slightly smaller. Type folding bike small diameter so quick. Usually the wheel size can not be replaced with different sizes, because it is limited to the size of the bike frame.
No tire tread width and there were narrow. Tires with good tread width for use in off-road terrain, because the force is large enough friction . However, when used on the road might be a bit heavy. Tires with good tread narrower use on the highway and the terrain is flat, but it is risky when used in off-road terrain.
Keeping the bike always smooth motion components, can be done by giving a little lubricant. This can reduce the friction between the components slightly aggravate stroke. However, if excessive, the lubricant will catch a lot of dust from the air so that the components will be quickly soiled.
The sitting position should be regulated so optimal, not too low or too high. The position is too low to make the stroke feels heavy and may cause injury. The position is too high to make the legs can not stand properly, and can also cause injury.
fixed Gear
Fixed Gear itself is a name quite literally, this is not a nickname, cool name, or acronym. Fixed = glued / immovable / patents and Gear = gear / gear. So logically Fixed Gear is a gear that does not move, less so understanding.
In simple, which drives a bike (or other vehicle) is a section called "Drive train."
Drive train itself is actually a combination of various components that
are interconnected and constitute the basis of a bicycle drive system,
consisting of pedals, crank arms (crank arm), the front gear (chain ring),
the rear gear (cog), and of course, the chain (chain).
Combined parts in the pedal known as the "Crank" or "crank set", ie pedal, crank arm and chain ring. Then the chain would circle cog chain ring and tied connected to the rear wheels.
When
the pedal is stepped on, crank arm will follow, rotate chain ring
attached, which then pulls the chain that also automatically invite cog
to rotate, and because he was attached to the rear wheel, the wheel turn
around and glide us. Simple mechanism, which more or less has never changed since the creation of this system.
The simplicity of this system brings an obstacle. Entanglement all drive train components are that make the logic of "turning the pedals, the rear wheel was spinning" can walk. By the same logic, meaning that as long as the rear wheels spin, the pedals will rotate.
Because all components of the drive train is bound to die one another, with no free movement. The
rear gear which only rotates to follow rotation of the chain or wheel
known as "Fixed Gear." Pedal is turned forward, the rear wheels spinning
forward. Pedal rotated to the rear, the wheels spin backwards. And vice versa.
Because
of the relation between the legs, crank, chain and rear wheel are to be
"one", then to set the rate of speed of rotation of the wheel can be
controlled by our own leg muscles. Even to stop the bike in total can be done with a fixed gear bikes without brakes aid in general. So
the use of brakes on a fixed gear bike into an optional choice, whether
riders want more secure by installing a brake or fairly confident in
his ability to stop the bicycle with leg power alone. This mechanism is different from the brake "Torpedo", which will be described hereinafter.
About 20 years after the system was created "chain drive" fixed gear
this, comes a new technology known as "Freewheel", or literally, "Roda
Free."freewheelfreewheel mechanism
Freewheel itself is a rear gear system that gives the freedom of the rear wheels spin independen of the pedal. So
when the pedal is rotated, the chain and the rear wheels will follow as
usual, but when the legs stop turning the pedals, chains joined stopped
moving, the rear gear stopped rotating, but the rear wheels can still
rotates with momentum. Freewheel drive train arguably just locked unidirectional only.
Because
the rear wheels is now not locked die with the rotation pedal, the bike
can be more comfortable cycling, using the technique of "coasting."
(Drove without constantly turning the pedals) Freewheel is more
frequently encountered in the bicycles are modern and all its forms, from children's bicycles to the Tour de France.
The brake system "Torpedo", a bicycle that stepped on the brakes method. Torpedo brake itself is mounted on a bicycle-based freewheel, and become an internal part of the rear wheel hub. Bicycles torpedo can be identified from a small lever that comes out of the rear hub and "tied" to the bicycle frame seat stay. At first glance looks like a bicycle could torpedo a fixed gear bike
break less / without brakes, but because drive train based freewheel,
he will not be categorized into fixed gear bikes.
Bicycles Fixed Gear / Fixie / Doort rap is a bike that drive train not use the freewheel. All forms of bikes, all colors, regardless of function, size and
number of wheels, the brand, can be categorized into a fixie when
drive train system using fixed / without freewheel.Types of bicycles
Now the bike has a variety of names and models. Grouping is usually based on the function and size.
Mountain bike, used for off-road with a strong frame, suspension, and a combination of speed up to 27.
Road bike, used for road racing, the overall light weight, smooth
tires to reduce friction with the road, the combination of speed up to
27
Bicycles BMX, which stands for bicycle moto-cross, widely used for attractions
City bike (City bike) is a bicycle commonly used in urban areas with good road conditions. Bicycles types of highly stressed fungsional aspect. Usually has a luggage rack and basket.
Bicycles kind City bike with lift and basket
Mountain bike, used for off-road with a strong frame, suspension, and a combination of speed up to 27.
Road bike, used for road racing, the overall light weight, smooth
tires to reduce friction with the road, the combination of speed up to
27
Bicycles BMX, which stands for bicycle moto-cross, widely used for attractions
City bike (City bike) is a bicycle commonly used in urban areas with good road conditions. Bicycles types of highly stressed funsional aspect. Usually has a luggage rack and basket.
Bicycles kind City bike with lift and basket
Mini bikes, included in this group are children's bicycles, both two-wheeled and three-wheeled
Bicycle transportation or bike classic design (old), included in
this group are moped, bicycles and bicycle posts that have strong iron
and large wheel diameter capable for both tandem and carry items.
Folding bike, a type bike that can be folded in seconds so that it can be taken anywhere with ease
Racing bikes, bike models semicircle and their handlers are used for the race.
Motorcycles, powered by a fuel manifold using gasoline as the primary power source. With the growing technology on a two-wheeler industry.
X . IIIII
TELECOMUNICATION TRANSMISSION
Characteristics of Telecommunications Transmission System ; 
eLEMENT OF TRANSMISSION
Transmission is a process of transporting information from a point that acts as a transmitter (sender information) to another point that acts as a receiver (receiver of information) where the distance between points can be very far away. The points that there could be many in number and form a telecommunications network. To connect between the network element requires an interface system called the transmission system.
Transmitter: On the transmitter occurs processing the input signal (which includes encoding and modulation) into an output signal corresponding to the transmission channel.
Transmission Channel: Channel is a media transmission link between the transmitter with the receiver. In the process of transmission, the signal will suffer attenuation caused by the transmission channel itself. The farther the distance transmission of data, then the greater the damping will occur.
Receiver: At the receiver, the received signal will be reprocessed. This processing includes filtering is filtering out noise contained in the signal, namely the strengthening of reinforcing the signal amplitude attenuation that has been exposed, equalization, and demodulating and decoding the signal format that is to return to its original shape .
TRANSMISSION CHANNELL
GENERALSubmission
of information from an information source to the receiver of
information can be accomplished when there is a media delivery system or
in between. If
the distance between the source of information to the receiver near the
information, the transmission system that is used simply through the
air. However, if the distance of both remote and very remote, it takes a more complex transmission system. The transmission system can consist of one or more transmission media. The medium used in this system can be either physical media (cable) and non-physical (wireless).Physical transmission medium is a transmission medium that has a physical form. Physical
media is generally using cables, wave guide or optical fiber, while the
non-physical media such as air or free space (free space). The transmission line is a very important component in the transmission system both wired and wireless systems. In the wireless transmission system, the transmission line is used to
connect the transmitter with a transmitter and receiver antenna and
receiver.
II. MEDIA TYPES OF TRANSMISSION LINES
Although it is common media used on the transmission channel high
frequency or microwaves (microwaves) can be either a conductor or a
hollow conductor, but the application can we distinguish in four
categories, namely:a. Two parallel wire transmission line (two-wire transmission line)b. Coaxial transmission line (coaxial transmission line)c. Micro strip and strip lined. A wave guide (wave guides)
Two-wire
transmission line is only suitable for use in areas lowest frequency of
the radio frequency spectrum because the higher frequency transmission
line of this type have a very large attenuation. To
fix the limitations of two-wire line is then at higher frequencies, use
parallel conductor pair is replaced by a pair of conductors are
arranged in the same axis, called a "coaxial". With this channel attenuation experienced by electromagnetic fields can be reduced. In the area of higher frequencies (microwaves), coaxial channel is
not suitable for electromagnetic wave propagating in the form of
radiation penetrating the dielectric material channel so that the
damping increases.For that, use a channel in the form of a hollow conductor, called a wave guide. As for linking short distances, at these frequencies typically used so-called strip line transmission lines and
microwave. Based on the physical construction of the transmission line can be distinguished, namely:
2 Two-wire (Twin Lead)Is a two-wire line that consists of a pair of parallel conductors separated by a dielectric material types polythylene. These
channels usually have a characteristic impedance 300sampai 600dan
widely used to connect a television receiver and the receiver in the
area of Very High Frequency (VHF). Physical structure can be seen in Figure 2.1. The
dotted lines in the figure indicate the magnetic field arises around
the inductor, while the line is not dashed showed electric field.
figure two wire line
3 Coaxial Line
An unbalanced line (unbalanced line), where one of its wires are used as a protector for the other wires in the same axis. Her second wires are separated by a dielectric material Polyethelyne or teflon.
The transmission line is most widely used to transmit radio frequency energy (RF), both the transmitter and receiver system. Impedance characteristics vary, ranging from 50 Ω to 75 Ω. The physical structure and the pattern of the terrain can be seen in Figure 2.2 where the dotted lines indicate the magnetic field, while the line is not dashed showed electric field.
Figure coaxial cable
4 Balanced Shielded LineIs
a fusion of two channels of wire line and coaxsial, where his two wires
parallel to each other, but to reduce the losses of radiation used
protective (shielded) of braided metal fibers such as the coaxial line. This cable has better characteristics than the two-wire cable.
5 Microstrip and striplineIs a form of physical transmission channel in the form of wires that are stiff. The
transmission line of this type typically used to work at microwave
frequencies region (order GHz) and is used to connect electronic devices
within close. Microstrip channel usually made in the form of primed Cabling Board
(PCB) with a special material that has low losses at microwave
frequencies.
6 pointer wave (waveguides)A
waveguide (waveguides) is a single channel that serves to deliver the
electromagnetic wave (microwave) with a frequency of 300 MHz - 300 GHz. In fact, the waveguide is a transmission medium that serves to guide the waves in a particular direction. At very high frequencies, above 1 GHz, the transmission line is no
longer effective as a medium for the transmission of electromagnetic
waves, such as the frequency of the radiation effects of channel
attenuation is already too big.The characteristic impedance and wave propagation mode in this type of channel different from previous types. One application of this waveguide is an optical fiber. Although
the condition is shaped wires, but the fiber optics transmission line
type "waveguide", in this case, a circular waveguide (circular
waveguide). Other applications that are as feeder (feeder) on a dish antenna. The waveguide as in the picture
CHARACTERISTICS OF TRANSMISSION LINES
When
the relationship between the signal source to the load is in progress,
then the signal will propagate in pair wires to the transmission line to
the other with a certain speed. The longer the transmission line, the travel time of the signal propagation will be longer. The
current flowing along the channel will generate a magnetic field that
surrounds the wires and sometimes each other coincides with the magnetic
field emanating from the wires around them. The magnetic field generated by an electric current carrying wires, a
pile of stored energy in the wires so that it can be considered that the
wires are inductive or inductance.Tension that exists between the two wires will generate an electric field. The
electric field is also a heap of energy may also benefit coincides with
the electric field around them, so that there will be capacitance
between two wires. For long channel,
inductance and capacitance will be spread evenly on all the channels
and the amount depends on the frequency of signals or waves that
propagate therein.Each
type of two-wire transmission line also has a conductance value that is
a value that represents the possibility of the number of electrons that
flow (current) passing through or penetrate dielectrics channels. If the channel is considered to be uniform (uniform), where all values
are the same magnitudes along the channel, then small pieces of the
channel can be considered to represent the overall length.
IV. IMPEDANCE CHARACTERISTICS
Waves that propagate on the transmission line length is infinite, it will not affect what is at the threshold of the channel. Comparison
between threshold voltage and current input channel can actually be
considered equal to the ratio between the voltage and current after
reaching the other end. It has been suggested that the current and voltage between the two wires looked channels as a transmission line impedance. Impedance is called "Characteristic Impedance (ZO)".
ZO = forward current / voltage forward. ................................... (2.1)
So
it can be said that the characteristic impedance is the impedance
measured at the threshold of the transmission line of infinite length. When power is propagated on the transmission line infinitely long, then power it
will
be absorbed entirely along the channel as a result of the leak current
in the capacitance between the conductor and the loss of voltage on the
line inductance.
Characteristic Impedance Measurement
In the Figure, it is shown that the impedance seen at the point of 1'-2 'to 1-2 finite) to the right is of ZO well. But with the voltage and current levels are smaller than the voltage at the point 1-2. So if the impedance at the point of 1'-2 'is replaced with a load
impedance of ZO, then the impedance of ZO at point 1-2 going well.The characteristic impedance channel lossless (losses-line) can be written as follows:ZO = (root L / C) [W / m] ..... ................................ ................ (2.2)Where :L = total inductance two wires along the line l (Henry)C = capacitance between the two wires length l (Farad)
Large characteristic impedance of a transmission line or waveguide is
different and its value is determined by the physical size and the cross
section of the dielectric material used as an insulator.
V. LOSS-OF INCOME (LOSSES) ON TRANSMISSION LINES
The voltage and current of a signal that propagates along the
transmission line will decrease with distance is longer, this means that
the transmission line has a loss.There are generally three kinds of losses contained in the transmission line that is being passed signals, namely:
a. Loss-Loss CopperLoss-loss,
among others in the form of power dissipation (I2R) in the form of heat
resistive and losses due to the skin effect (skin effect). The higher the frequency, the greater the resistance caused by the skin effect, so this result in losses greater channel. So in addition to the resistance caused by alone, losses
of copper is also due to the skin effect, which causes the resistance
of the conductor at high frequency also increases.
b. Dielectric Loss LossThis loss incurred due to the warming that has occurred on the wires when the current passed back and forth. Power is transmitted source signal is partially converted into heat which occursthe dielectric material. When
the current passed back and forth, then the atomic structure of the
dielectric material will undergo a change and the change requires
energy. It is this energy that gives rise to power losses. The more difficult the atomic structure of a dielectric material
change, the greater its energy needs, which means the greater the power
loss caused by it.
c. Loss-Loss Radiation and inductionThis loss occurs due to electromagnetic fields that exist around wires. Induction
losses occur when the electromagnetic field around the conductor of a
direct hit by a conductor that, consequently lost power at the
conductor. Radiation losses are losses that caused the loss of most of the lines
of magnetic force due to gushing out of the transmission line.Attenuation arising from losses in transmission line expressed in decibels per unit or neper per unit length.
E1 On Telecommunications Transmission
Is the E1?
E1 is a digital transmission medium used in the telecommunications world. If you enter the working world of telecommunications, you will often encounter such thing as E1. E1 is the standard digital transmission medium used in Indonesia and other countries like the United States. 1 E1 has 30 Time Slot with a speed of 2 Mbps.
So each time slot to send and receive an 8-bit samples, usually encoded according to the law-algorithm A, 8000 times per second (8 x 8000 x 32 = 2.048 million).
It is ideal for voice phone calls where the voice samples into 8 bit numbers at that data rate and reconstructed on the other end. The time slots are numbered from 0 to 31.
One time slot (TS0) is reserved for framing purposes, and alternately transmit a fixed pattern. This allows the receiver to lock on to the beginning of each frame and match each channel in turn.
cables E1
E1 cable has the following characteristics:
The outer skin is the same as wired LAN / UTP is colored gray black ato
2nd layer contained aluminum foil wrappers
a layer of plastic wrap to -3
Color: Blue / White - Green / White, Orange / White - Brown / White, Blue / Red - Green / Red, Orange / Red - brown / red,
There is a grounding wire
E1 cable is usually installed in the terminal DDF. DDF connect between devices that use wired E1 Telecommunication for Transmission media such as connecting to TRC MSC, MSC to BSC, BSC to Transmission.
Well, so first of this topic, in the next post I will discuss how to install the E1 cable on DDF.
X . IIIIII
Transmission on the lights
Do lenses affect light transmission?
Photographic lenses are
made of several elements of very pure glass, each element being
carefully coated to limit reflection. However, a portion of the light is
lost in the optical system due to residual reflection and absorption.
The
transmission factor (the proportion of light that actually makes its
way to the sensor) depends on the optical formula (the number of lenses,
the glass and coating formulas) and to a lesser degree on the shooting
parameters.
As a measure of transmission, DxOMark reports the
T-stop, defined as the f-number of a lens with 100% perfect
transmission, and resulting in the same illumination of the sensor at
the image center as the lens to be measured.
Light Absorption, Reflection, and Transmission
We have
previously
learned that visible light waves consist of a continuous range of
wavelengths or frequencies. When a light wave with a single frequency
strikes an object, a number of things could happen. The light wave could
be absorbed by the object, in which case its energy is converted to
heat. The light wave could be reflected by the object. And the light
wave could be transmitted by the object. Rarely however does just a
single frequency of light strike an object. While it does happen, it is
more usual that visible light of many frequencies or even all
frequencies is incident towards the surface of objects. When this
occurs, objects have a tendency to selectively absorb, reflect or
transmit light certain frequencies. That is, one object might reflect
green light while absorbing all other frequencies of visible light.
Another object might selectively transmit blue light while absorbing all
other frequencies of visible light. The manner in which visible light
interacts with an object is dependent upon the frequency of the light
and the nature of the atoms of the object. In this section of Lesson 2
we will discuss how and why light of certain frequencies can be
selectively absorbed, reflected or transmitted.
Visible Light Absorption
Atoms and molecules contain electrons. It is often useful to think of
these electrons as being attached to the atoms by springs. The
electrons and their attached springs have a tendency to vibrate at
specific frequencies. Similar to a tuning fork or even a musical
instrument, the electrons of atoms have a
natural frequency
at which they tend to vibrate. When a light wave with that same natural
frequency impinges upon an atom, then the electrons of that atom will
be set into vibrational motion. (This is merely another example of the
resonance principle
introduced in Unit 11 of The Physics Classroom Tutorial.) If a light
wave of a given frequency strikes a material with electrons having the
same vibrational frequencies, then those electrons will absorb the
energy of the light wave and transform it into vibrational motion.
During its vibration, the electrons interact with neighboring atoms in
such a manner as to convert its vibrational energy into thermal energy.
Subsequently, the light wave with that given frequency is absorbed by
the object, never again to be released in the form of light. So the
selective absorption of light by a particular material occurs because
the selected frequency of the light wave matches the frequency at which
electrons in the atoms of that material vibrate. Since different atoms
and molecules have different natural frequencies of vibration, they will
selectively absorb different frequencies of visible light.
Visible Light Reflection and Transmission
Reflection and transmission of light waves occur because the
frequencies of the light waves do not match the natural frequencies of
vibration of the objects. When light waves of these frequencies strike
an object, the electrons in the atoms of the object begin vibrating. But
instead of vibrating in resonance at a large amplitude, the electrons
vibrate for brief periods of time with small amplitudes of vibration;
then the energy is reemitted as a light wave. If the object is
transparent, then the vibrations of the electrons are passed on to
neighboring atoms through the bulk of the material and reemitted on the
opposite side of the object. Such frequencies of light waves are said to
be
transmitted. If the
object is opaque, then the vibrations of the electrons are not passed
from atom to atom through the bulk of the material. Rather the electrons
of atoms on the material's surface vibrate for short periods of time
and then reemit the energy as a reflected light wave. Such frequencies
of light are said to be
reflected.
Where Does Color Come From?
The color of the objects that we see is largely due to the way those objects interact with light and
ultimately
reflect or transmit it to our eyes. The color of an object is not
actually within the object itself. Rather, the color is in the light
that shines upon it and is ultimately reflected or transmitted to our
eyes. We know that the visible light spectrum consists of a range of
frequencies, each of which corresponds to a specific color. When visible
light strikes an object and a specific frequency becomes absorbed, that
frequency of light will never make it to our eyes. Any visible light
that strikes the object and becomes reflected or transmitted to our eyes
will contribute to the color appearance of that object. So the color is
not in the object itself, but in the light that strikes the object and
ultimately reaches our eye. The only role that the object plays is that
it might contain atoms capable of selectively absorbing one or more
frequencies of the visible light that shine upon it. So if an object
absorbs all of the frequencies of visible light except for the frequency
associated with green light, then the object will appear green in the
presence of
ROYGBIV.
And if an object absorbs all of the frequencies of visible light except
for the frequency associated with blue light, then the object will
appear blue in the presence of
ROYGBIV.
Consider the two diagrams below. The diagrams depict a sheet of paper being illuminated with white light (
ROYGBIV).
The papers are impregnated with a chemical capable of absorbing one or
more of the colors of white light. Such chemicals that are capable of
selectively absorbing one or more frequency of white light are known as
pigments.
In Example A, the pigment in the sheet of paper is capable of absorbing
red, orange, yellow, blue, indigo and violet. In Example B, the pigment
in the sheet of paper is capable of absorbing orange, yellow, green,
blue, indigo and violet. In each case, whatever color is not absorbed is
reflected.
Check
your understanding of these principles by determining which color(s) of
light are reflected by the paper and what color the paper will appear
to an observer.
Transparent materials are materials that allow one
or more of the frequencies of visible light to be transmitted through
them; whatever color(s) is/are not transmitted by such objects, are
typically absorbed by them. The appearance of a transparent object is
dependent upon what color(s) of light is/are incident upon the object
and what color(s) of light is/are transmitted through the object.
Express your understanding of this principle by filling in the blanks in the following diagrams.
Transmission of Light Defined
Visible
light is the reason we are able to see anything at all. Light moves as a
wave, bouncing off objects so we can see them. Without it, we'd be in
complete darkness. But, in physics, light can refer to any kind of
electromagnetic wave: radio waves, microwaves, infrared, visible light,
ultraviolet, X-rays, or gamma rays.
When you shine light on an object, a number of things can happen. Reflection is when light bounces off of a surface. Specular reflection is when light reflects off of a shiny surface like a mirror. Diffuse reflection, however, is when light illuminates a dull object.
Another
thing it can do is move through the material, and depending on exactly
how it does this, we might call it transmission, refraction, or
absorption. We will discuss each in more detail in this lesson, but transmission of light is when light waves move all the way through a material without being absorbed.
Transmittance
When light moves through a transparent (or semi-transparent) material, it can be transmitted, absorbed, or reflected. The transmittance of a material is the proportion of the incident (approaching) light that moves all the way through to the other side.
For
example, let's say you're shining a flashlight on a semi-transparent
glass block. You start off with 100% of your incident light. The first
thing that happens is that 30% of that light is reflected off the outer
surface of the glass. This leaves you with 70% to continue through the
glass block. Another 50% of the light is absorbed by the molecules
inside the glass block itself. That leaves you with 20% that emerges
from the opposite side. So you could say that the glass block has a
transmittance of 20%.
The transmittance of a material depends on
its thickness, but it also depends on the type of light (or
electromagnetic waves) you are using. A material might have a different
transmittance for visible light than it does for infrared, or X-rays.
This is why hospital X-rays go through your skin until they reach the
bones,even though visible light does not .
X . IIIIIII
Transmission on biology
nerve cell gif nerve cell transmission
How Antidepressants Work ?
So, what causes MDD? The exact cause is unknown, but research has focused on the balance of certain chemicals called
neurotransmitters, specifically
serotonin,
norepinephrine (also called
noradrenaline) and
dopamine.
These neurotransmitters, especially serotonin, are prevalent in the
areas of the brain -- like the limbic system and upper brainstem -- that
control mood and emotions.
Research indicates that patients with MDD either do not have enough
serotonin or norepinephrine in these areas of the brain or have an
imbalance between the two types of neurotransmitters. Antidepressants
are designed to increase the levels of these neurotransmitters in the
limbic system. So, to understand how antidepressants work, we must look
at the process of
neurotransmission.
Note
Many addictive drugs (like cocaine, methamphetamines, LSD, heroin and
marijuana) affect the same pathways and neurotransmitters as MDD does. |
Your brain and nervous system are made of nerve cells, or
neurons. Like wires in your home's
electrical system, nerve cells make connections with one another in circuits called
neural pathways. Unlike wires in your home, nerve cells do not touch, but they come close together at
synapses. At the synapse, the two nerve cells are separated by a tiny gap, or
synaptic cleft. The sending neuron is called the
presynaptic cell, while the receiving one is called the
postsynaptic
cell. Nerve cells send chemical messages called neurotransmitters in a
one-way direction across the synapse from presynaptic cell to
postsynaptic cell.
Let's see how the nerve communication process works.
|
- The presynaptic cell (sending cell) makes serotonin (5-hydroxytryptamine, 5HT) from the amino acid tryptophan and packages it in vesicles in its end terminals.
- An electrochemical nerve signal passes down the presynaptic cell into its end terminals.
- The
nerve signal stimulates the vesicles containing serotonin to fuse with
the cell membrane and dump serotonin into the synaptic cleft.
- Serotonin passes across the synaptic cleft, binds with special proteins called receptors
on the membrane of the postsynaptic cell (receiving cell) and sets up a
new electrochemical signal in that cell (the signal can stimulate or
inhibit the postsynaptic cell). Serotonin fits with its receptor like a
lock and key.
- The remaining serotonin molecules in
the cleft and those released by the receptors after use get destroyed
by enzymes in the cleft (monoamine oxidase (MAO) and catechol-o-methyl
transferase (COMT)). Some get taken up by specific transporters on the
presynaptic cell (reuptake). In the presynaptic cell, the
absorbed serotonin molecules get destroyed by MAO and COMT. This
enables the nerve signal to be turned "off."
A
similar process occurs for norepinephrine, which is also implicated in
mood, emotions and MDD. Serotonin, norepinephrine and dopamine are
chemically similar and belong to a class of neurotransmitters called
monoamine neurotransmitters. Because these chemicals are structurally similar, they are all recognized by the enzymes MAO and COMT.
Stephen Chernin/Getty Images
Prozac is one of the most
prescribed antidepressants.
|
Antidepressants
are designed to block various aspects of the synaptic transmission
process in serotonin, norepinephrine and dopamine-containing neurons in
the
brain. This
increases the levels of these neurotransmitters. By increasing the
levels of these neurotransmitters, mood and emotions should stabilize
and perhaps return to normal. However, because some of these
neurotransmitters (like norepinephrine) are contained in neural pathways
in other parts of the brain and nervous system, some antidepressants
can have side effects (like changes in
blood pressure
and saliva production). Also, because the pathways involved in MDD are
in the lower brain and brainstem, antidepressants may interfere with
other functions, like appetite,
sleep and
sexual function.
Antidepressants
are classified according to which neurotransmitters they affect and how
they affect them. Let's look at the different types of antidepressants.
Selective Serotonin Reuptake Inhibitors (SSRI)SSRIs,
the most frequently prescribed antidepressants, were introduced in the
mid-1980s. SSRIs block the transport of serotonin back into the
presynaptic cell. This action increases the concentration of serotonin
in the synaptic cleft, increasing stimulation of the postsynaptic cells.
SSRIs include the following drugs:
- fluoxetine (ProzacTM)
- paroxetine (PaxilTM)
- sertraline (ZoloftTM)
- fluvoxamine (LuvoxTM)
- citalopram (CelexaTM)
- escitalopram (LexaproTM)
The
various SSRIs are equally effective and equally tolerated by patients.
Not everyone reacts in the same way, however, so some patients may
experience more side effects with one type of SSRI than with another.
Most of the time, patients have to take antidepressants more than once
per day.
However, fluoxetine has a longer half-life -- it remains in the body
longer, so
patients can usually take it once a day. This lowers the chance of
missing a
dose. At high doses, paroxetine and sertraline will interfere with
dopamine and serotonin neurotransmission.
To minimize side
effects that might cause a patient to stop using the drug, primary
health-care providers usually start SSRIs at low doses and slowly
increase to the target dose over four to six weeks. Such side effects
include
nausea,
dizziness,
vertigo,
vomiting,
insomnia,
anorexia,
anxiety and
sexual dysfunction.
Tricyclic Antidepressants and Selective Norepinephrine Reuptake InhibitorsTricyclic
antidepressants were introduced in the late 1950s and early 1960s. Like
SSRIs, these compounds block the reuptake of norepinephrine by the
presynaptic cell, thereby increasing its concentration in the synaptic
cleft. Tricyclic antidepressants include:
- nortryptiline (PamelorTM)
- maprotiline (LudiomilTM)
- desipramine (NorpramineTM)
- amitryptiline (ElavilTM)
- clomipramine (AnafranilTM)
- imipramine (TrofranilTM)
Tricyclic
antidepressants affect heart rate and blood pressure because
norepinephrine is also used in the autonomic nerves that control these
functions. Their side effects include postural
hypotension (drop in blood pressure upon standing),
tachycardia (rapid heart rate), dry mouth, urinary retention and blurry
vision.
Tricyclic antidepressants are not used often because they are toxic and
easily overdosed. However, for patients who do not tolerate SSRIs or
other antidepressants, tricyclics are effective. Physicians must monitor
the patient closely for toxic side effects.
Tricyclic
antidepressants are nonselective inhibitors of norepinephrine reuptake
because their chemical structures look like norepinephrine. Reboxetine
(Edronax
TM) is a more specific reuptake inhibitor because it binds better to the reuptake transporter, but it isn't available in the
United States.
Serotonin-Norepinephrine Reuptake Inhibitors (SNRI)These
drugs were introduced in the mid-1990s and block the reuptake of both
serotonin and norepinephrine by binding to the transporters of these
neurotransmitters on the presynaptic cell. SNRIs include:
- bupropion (WellbutrinTM) -- blocks dopamine and norepinephrine reuptake as well
- duloxetine (CymbaltaTM)
- venlafaxine (EffexorTM)
The
side effects of these drugs are similar to, but less than, those of
SSRIs. Bupropion and duloxetine, in particular, have minimal side
effects in the areas of
sexual dysfunction and weight gain.
Monoamine Oxidase Inhibitors (MAOI)An
enzyme called monoamine oxidase can degrade serotonin and
norepinephrine in the synaptic cleft and presynaptic cell. MAOIs block
this degradation, increasing the concentration of the neurotransmitters.
MAOIs include:
- phenelzine (NardilTM)
- tranylcypromine (ParnateTM)
- selegiline (EldeprylTM)
- isocarboxazid (MarplanTM)
- moclebemice (ManerixTM)
Because
these drugs can interfere with norepinephrine, they can have
cardiovascular side effects. Most commonly, patients must limit their
consumption of
foods containing
tyramine because the drugs interact with tyramine to cause
hypertension
(high blood pressure). Tyramine can be found in foods like soy sauce,
sauerkraut, chicken and beef livers, aged cheese, sausage, cured meat
and fish, yogurt, raisins, figs and sour cream. Patients also have to
refrain from consuming
alcohol
when on these antidepressants. Because of these interactions, doctors
do not prescribe this class of antidepressants as frequently as others.
Noradrenergic and Specific Serotonin Antidepressants (NaSSA)Some
of these compounds were introduced in the mid-1980s and others even
more recently. NaSSAs block negative feedback effects on norepinephrine
and serotonin secretion by the presynaptic cell. This action increases
the concentrations of these neurotransmitters in the synaptic cleft.
They also block some serotonin receptors on the postsynaptic cell, which
enhances serotonin neurotransmission. These compounds include
- Mirtazipine (RemeronTM)
- Trazodone (DesyrelTM)
- Nefazodone (SerzoneTM)
- Mianserin (BolvidionTM)
The most common side effects are drowsiness, dry mouth, increased appetite and weight gain.
Remember
that the available antidepressants are about equally effective in
treating MDD. So, choices are based on patient's age, family history,
drug tolerance, side effects and past response to antidepressants.
Acute phaseHere, the goal is to get the patient
into remission (a state with minimal symptoms). This usually involves
beginning antidepressant therapy. Usually, SSRIs are the drug of choice,
especially for children and older patients, because they can be used in
lower dosages with the fewest side effects. It takes about four to six
weeks for any antidepressant to show effects.
Augmenting Antidepressants
Sometimes
MDD patients show other symptoms (changes in mood, delusions,
hallucinations, changes in energy metabolism) partially due to
antidepressant side effects or to other types of depression (like
bipolar disorder -- periods of happiness interspersed by periods of
severe depression). So, primary care providers may add other
medications to antidepressant therapy.
- Mood stabilizers: lithium, latmotriguine (LamictalTM), valproic acid (DepakeneTM, DepakoteTM)
- Antipsychotic agents: chlorpromazine (ThorazineTM) or haloperidol (HaldolTM)
- Thyroxine: thyroid hormone to increase metabolism
|
The
physician and patient start by rating the severity of the untreated
symptoms to establish a baseline. During the first four to six weeks on
antidepressants, patients may undergo psychotherapy and side-effect
monitoring. The physician reassesses the severity of the symptoms and
compares them to the baseline. If, after eight weeks, the reduction in
severity is less than 25 percent, that antidepressant is considered to
offer no improvement. The primary care provider may choose to change the
dosage or class of medication, augment the medication or combine
classes of antidepressants. If successful, the acute phase of treatment
may six to 10 weeks.
Continuation phaseAfter
remission begins, doctors try to eliminate remaining symptoms, restore
the patient to his or her level of function before the MDD episode and
prevent recurrence of further MDD episodes. During this time, the levels
of antidepressant therapy and psychotherapy used to achieve remission
are maintained. If, after six months, there is no relapse, medication
might be discontinued gradually over several weeks. The continuation
phase of treatment could last six to 12 months.
Maintenance phaseThis
phase is most important for patients with annual episodes of
depression. During this time, patients should be monitored regularly.
Antidepressant therapies sometimes have to be reinitiated. Psychotherapy
and patient education are especially important. The maintenance phase
can last one to three years.
Special populations and depression therapyWhen deciding on therapy, some clinically depressed patients require special considerations:
- Bipolar disorder
-- these patients have extreme mood swings (periods of excessive high
spirits followed by severe depressive episodes). Typically, the
antidepressants are augmented with mood stabilizers.
- Children/adolescents
-- The SSRI fluoxetine is the only effective (and approved)
antidepressant for this age group. There have been reports that children
on antidepressants are more likely to commit suicide than those who are
not on antidepressants; while some data suggest that this may be true,
it has not been proven conclusively. Primary care providers need to
weigh the risks of antidepressant therapy versus untreated depression.
Most often, treatment carries fewer risks of suicide than non-treatment.
- Pregnant/postpartum women -- Depression can be a common symptom during pregnancy
and postpartum -- it usually corrects itself, but sometimes severe
depression must be treated (in about 10 percent of pregnant/postpartum
women). Antidepressants can pass to the fetus and through breast milk.
The effects of antidepressants on the developing fetus and newborn are
not well known. Therefore, doctors should carefully consider the risks
and benefits of treatment.
Treatment for
depression is not a short-term process but a long-term project with
specific goals of remission and maintenance. Multiple approaches of
medication, psychotherapy and patient education are most effective in
the treatment of MDD. Close consultation with a physician and/or
psychiatrist can provide the best treatment options.
another example transmission biology :
Prion-like transmission of protein aggregates in neurodegenerative diseases
Protein folding proceeds through intermediates, which expose hydrophobic
amino acid side chains on their surfaces that are normally buried in
the interior of the native state, and are therefore prone to
self-associate into non-native oligomers (see the figure, part
a).
Molecular chaperones of the heat shock protein 70 (HSP70) family
interact transiently with these aggregation-prone surfaces (see the
figure, part
b). They either compete with
self-association or favour the formation of native contacts and help
maintain intermediates in a monomeric, folding-competent state.
Mutations or polymorphisms can destabilize the native state or decrease
the efficiency of folding. Insufficient amounts of molecular chaperones
also affect folding efficiency. Incompletely folded proteins are tagged
with polyubiquitin chains, which direct them to the 26S proteasome for
degradation (see the figure, part
c). Molecular
chaperones contribute to this process by maintaining the proteins in a
state that can be unfolded by the 26S proteasome. Proteins that escape
degradation by the 26S proteasome can be degraded by lysosomes through
macroautophagy (see the figure, part
d).
Autophagic degradation begins with the capture of the substrate proteins
(or aggregates) into phagophores that mature into autophagosomes — a
vesicular structure enclosed by two concentric lipid bilayer membranes.
Autophagosomes fuse with organelles of the endosomal and lysosomal
pathways to form autolysosomes that, endowed with acidic pH and
lysosomal hydrolases, are able to degrade proteins without the need to
unfold them. Finally, the interaction of protein aggregates with the
minus end-directed microtubule motor cytoplasmic dynein results in their
accumulation around the centrosome or microtubule organizing centre
(see the figure, part
e). This process may
facilitate the capture of aggregates by macroautophagy or may serve to
concentrate potentially toxic aggregation nuclei in a defined region of
the cell.
Native (sphere) prion molecules undergo conformational changes that lead to an abnormal (cube) form (see the figure; part
a, step 1). This event is unfavourable because the abnormal form is either unstable (part
a,
step 2) or sensitive to clearance. According to the 'template
assistance' model, prions in their abnormal form interact with native
prions (part
a, step 3) and convert them into the abnormal form (part
a,
step 4). The alternative 'seeded polymerization' model proposes that
abnormal prions have the ability to interact with molecules in a similar
state (part
a, step 5). The oligomeric species
formed are unstable because the intermolecular interactions do not
outweigh the entropic cost of binding. They grow by the incorporation of
abnormal prion molecules (part
a, step 6) and dissociate (part
a,
step 7) until a stable nucleus is formed. Such a stable prion aggregate
can then grow indefinitely from one or both ends and can also break
into smaller fragments (part
a, step 8) that act as nuclei (part
a, step 6).
Prion
aggregates bind to native prion molecules or receptor proteins attached
to the cell membrane, and are internalized by endocytosis (part
b,
step 1). They reach the cytoplasm, by an unknown process, where they
grow by the incorporation of cytosolic prions. They can move along the
axon in one direction or another (part
b, step 2) and can reach neighbour cells through axon–dendrite connections (part
b, step 3) and nanotubes (part
b, step 4).
Prions
and polypeptides involved in Parkinson's, Alzheimer's and Huntington's
diseases form aggregates that resist protein denaturation treatments
(see the figure, part
c). This process can be
monitored experimentally. Stable oligomer formation is thermodynamically
unfavourable and this is reflected by a nucleation phase. The stable
oligomers elongate in an exponential manner until the soluble protein
concentration reaches the critical concentration, above which assembly
occurs. These events give a sigmoidal shape to the assembly kinetic (see
the figure, part
c; green curve). The nucleation phase is abolished (see the figure, part
c; orange curve) when preformed aggregates that act as seeds are added to the protein solution.
Protein folding proceeds through intermediates, which expose
hydrophobic amino acid side chains on their surfaces that are normally
buried in the interior of the native state, and are therefore prone to
self-associate into non-native oligomers (see the figure, part
a).
Molecular chaperones of the heat shock protein 70 (HSP70) family
interact transiently with these aggregation-prone surfaces (see the
figure, part
b). They either compete with
self-association or favour the formation of native contacts and help
maintain intermediates in a monomeric, folding-competent state.
Mutations or polymorphisms can destabilize the native state or decrease
the efficiency of folding. Insufficient amounts of molecular chaperones
also affect folding efficiency. Incompletely folded proteins are tagged
with polyubiquitin chains, which direct them to the 26S proteasome for
degradation (see the figure, part
c). Molecular
chaperones contribute to this process by maintaining the proteins in a
state that can be unfolded by the 26S proteasome. Proteins that escape
degradation by the 26S proteasome can be degraded by lysosomes through
macroautophagy (see the figure, part
d).
Autophagic degradation begins with the capture of the substrate proteins
(or aggregates) into phagophores that mature into autophagosomes — a
vesicular structure enclosed by two concentric lipid bilayer membranes.
Autophagosomes fuse with organelles of the endosomal and lysosomal
pathways to form autolysosomes that, endowed with acidic pH and
lysosomal hydrolases, are able to degrade proteins without the need to
unfold them. Finally, the interaction of protein aggregates with the
minus end-directed microtubule motor cytoplasmic dynein results in their
accumulation around the centrosome or microtubule organizing centre
(see the figure, part
e). This process may
facilitate the capture of aggregates by macroautophagy or may serve to
concentrate potentially toxic aggregation nuclei in a defined region of
the cell.
X . IIIIIIII
TRANSMISSION ON ASTRONOMY
Atmospheric Transmission--Good News and Bad News
It is not coincidence that our eyes are sensitive to optical light
waves. Optical
light can travel nearly unimpeded through our atmosphere, and so our
eyes have adapted
themselves to be sensitive at these wavelengths. For thousands of
years, optical
light was our only "window" on the Universe, and even then the primary
"instrument" was
the naked eye. When Galileo first turned his telescope skyward, he
opened this window
a little farther and saw many marvelous things for the first time. Yet,
as is discussed elsewhere in these pages, optical light is a small
portion of the entire range
of electromagnetic radiation. How much more could we learn about the
Universe if
we could use the entire EM spectrum?
Most of the rest of the EM spectrum gets absorbed or blocked by the atmosphere, and
it's a good thing, too! Just a tiny portion of ultraviolet light leaking through
the atmosphere is enough to give us a painful sunburn if we aren't careful. Can
you imagine what earth would be like if ultraviolet or X-ray light could get
through the atmosphere? Suffice it to say that we wouldn't be around to
"see" it--we would have long since been fried by our own sun! The atmosphere is
"good news" from the perspective of life on earth. But
the atmosphere is "bad news" if we want to see the Universe at these
wavelengths.
This graphic shows schematically how the atmosphere lets some light through while
blocking most kinds of light like X-ray, ultraviolet, and parts of the infrared.
Radio light was the first window after the optical one to be used for astronomy. This is
because certain portions of the radio spectral region can pass through the atmosphere
and be detected from cosmic sources. As a matter of fact, radio astronomy grew
out of the development of radar techniques during World War II. As the first sensitive
radio receivers were built, users noticed a persistent faint radio noise that they
could not identify. It turns out this "noise" was due to cosmic sources of radio
radiation being picked up by accident. Radio astronomy was born!
Certain portions of the infrared spectral region can get through the atmosphere, at
least partially. Observatories at high altitude (above most of the water vapor in
the atmosphere) can do quite well in certain small wavelength ranges. And special
infrared telescopes have been flown on high-flying aircraft to open this window
even further. However, many portions of the infrared spectrum get completely
absorbed in the atmosphere.
While much can be learned from optical observations, there is also much unique
information
to be gained from observations in other wavelength ranges that are hidden by the
curtain of our atmosphere. For astronomers to observe in most of the EM spectrum,
we need to get telescopes in space. It has only been over the last 35 years that this
has been possible, with rockets that can lift special telescopes above the atmospheric
curtain. Telescopes have now been flown to observe across the entire spectrum!
For astronomers, that's good news!
Astronomical filter
Ultraviolet
filters used in astronomy for blocking the ultraviolet radiation, which
causes the camera to heat up when photographing (without affecting the
image).
An
astronomical filter is a
telescope accessory used by
amateur astronomers to simply enhance the details of
celestial objects (much as with amateur photography). By contrast
professional astronomers rigorously use
filters on telescopes in order to understand the
astrophysics (such as
stellar classification and placement of a
celestial body on its
Wien Curve), occurring for the object in a given
bandpass via
photometry.
Most astronomical filters work by blocking a specific part of the color spectrum above and below a
bandpass,
significantly increasing the signal to noise of the interesting
wavelengths, and so making the object more visible, 'contrasty', or
defined. While the color filters transmit certain colors from the
spectrum and are usually used for observation of the
planets and the
Moon,
the polarizing filters work by adjusting the brightness, and are
usually used for the Moon. The broadband and narrowband filters transmit
the wavelengths that are emitted by the
nebulae (by the
Hydrogen and
Oxygen atoms), and are frequently used for reducing
light pollution.
Solar filters
Solar filters block most of the sunlight to avoid any damage to the
eyes. They are usually made from a durable glass or a plastic film which
transmits 1/100,000th of the light. Film filters are used over the
aperture of the telescope and do not heat up significantly, whereas
glass filters are used near the objective end causing them to heat up
greatly and it is not unknown for them to shatter from thermal shock.
Glass solar filters are therefore not recommended by most experts and
some stockists refuse to sell them or remove them from telescope
packages. "Solar filters designed to thread into eyepieces that are
often provided with inexpensive telescopes are also unsafe. These glass
filters can crack unexpectedly from overheating when the telescope is
pointed at the Sun, and retinal damage can occur faster than the
observer can move the eye from the eyepiece."
They are used for observation, photography, and for viewing the
sun as a yellow-orange disk. With a telescope, these filters can view the details of the sun directly and safely, especially the
sunspots and
granulation of the surface.The
Herschel Wedge
is a prism based device used in conjunction with a neutral density
filter that directs most of the heat and ultra violet light out of the
telescope, generally giving better results than most filters. Another
filter used for solar observing is the hydrogen-alpha filter, which
transmits the
H-alpha spectral line. These filters can view the
solar flares and
prominences that are not visible in the normal solar filters.
Color filters
Color filters work by absorption/transmission, and can tell which
part of the spectrum they are reflecting and transmitting. Filters can
be used to increase contrast and enhance the details of the Moon and
planets. All of the visible spectrum colors each have a filter, and
every color filter is used to bring a certain lunar and planetary
feature; for example, the #8 yellow filter is used to show
Mars's maria and
Jupiter's belts. The Wratten system is the standard number system used to refer to the color filter types. It was first manufactured by
Kodak in 1909.
Professional filters are also colored, but their bandpass centers are placed around other midpoints (such as in the
UBVRI and Cousins systems).
Some of common color filters and their uses are:
- Chromatic aberration filters: Used for reduction of the purplish halo, caused by chromatic aberration of refracting telescopes.
Such halo can obscure features of bright objects, especially Moon and
planets. These filters have no effect on observing faint objects.
- Red: Reduces sky brightness, particularly during daylight and twilight observations. Improves definition of maria, ice, and polar areas of Mars. Improves contrast of blue clouds against background of Jupiter and Saturn.
- Deep yellow: Improves resolution of atmospheric features of Venus,
Jupiter (especially in polar regions), and Saturn. Increases contrast
of polar caps, clouds, ice and dust storms on Mars. Enhances comet
tails.
- Dark green: Improves cloud patterns on Venus. Reduces sky
brightness during daylight observation of Venus. Increases contrast of
ice and polar caps on Mars. Improves visibility of the Great Red Spot on Jupiter and other features in Jupiter atmosphere. Enhances white clouds and polar regions on Saturn.
- Medium blue: Enhances contrast of Moon. Increases contrast of
faint shading of Venus clouds. Enhances surface features, clouds, ice
and dust storms on Mars. Enhances definition of boundaries between
features in atmospheres of Jupiter and Saturn. Improves definition of comet gas tails.
Moon filters
Neutral density filters, also known in astronomy as Moon filters, are another approach for contrast enhancement and
glare
reduction. They work simply by blocking some of the object's light to
enhance the contrast. Neutral density filters are mainly used in
traditional photography, but are used in astronomy to enhance lunar and
planetary observations.
Polarizing filters
Polarizing filters adjust the brightness of images to a better level
for observing, but much less so than solar filters. With these types of
filter, the range of transmission varies from 3% to 40%. They are
usually used for the observation of the Moon, but may also be used for planetary observation. They consist of two polarizing layers in a rotating
aluminum cell,
which changes the amount of transmission of the filter by rotating
them. This reduction in brightness and improvement in contrast can
reveal the lunar surface features and details, especially when it is
near full. Polarizing filters should not be used in place of solar
filters designed specially for observing the sun.
Nebular filters
Narrowband
The three main spectral lines that Narrowband filters transmit
Narrowband filters are astronomical filters which transmit only a narrow band of
spectral lines from the spectrum (usually 22 nm or less). It is mainly used for
nebulae observation.
Emission nebulae mainly radiate the doubly
ionized oxygen in the
visible spectrum, which emits near 500 nm wavelength. These nebulae also radiate weakly at 486 nm, the
Hydrogen-beta
line. There are three main types of Narrowband filters: Ultra-high
contrast (UHC), Oxygen-III & Hydrogen-beta, and Hydrogen-alpha, the
narrowest of the three filters with 8 nm range. The UHC filters range
from 484 to 506 nm. It transmits both the O-III and H-beta spectral lines, blocks a large fraction of light pollution, and brings the details of
planetary nebulae and most of emission nebulae under a dark sky.
Broadband
The
broadband, or light pollution reduction (LPR), filters are nebular
filters that block the light pollution in the sky and transmit the
H-alpha,
H-beta, and
O III spectral lines, which makes observing nebulae from the city and light polluted skies possible. These filters block the
Sodium and
Mercury vapor light, and also block the natural skyglow such as the auroral light
The broadband filters differ from the narrowband with the range of
wavelengths transmission. LED lighting is more broadband so this is not
blocked although white LEDs have from themselves a considerably lower
output around 480 nm which is close to O III and H-beta wavelength. The
broadband filters have a wider range because the narrower transmission
range causes a fainter image of sky objects, and since the work of these
filters is revealing the details of nebulae from light polluted skies,
it has a wider transmission for more brightness.These filters are particularly designed for nebulae observing, are not useful with other
deep sky objects. However, it can improve the contrast between the DSOs and the background sky, which may clarify the image.
Transmission and time Efficiency
Photon collecting efficiency
- Efficiency
- Transmission efficiency
- QE, Filterloss, Time efficiency
- Conclusion
1: Efficiency
Have you ever thought about how efficient you collect/detect photons?
Every lens surface transmit about 99%, every mirror surface reflect about 92%, it could be worse or it could be better.
But there is a system of optical parts and together they make up significant losses.
And then there is also limitations in the sensor efficiency, the QE.
And you also loose time between every sub image you take.
I have collected this losses in a table so you can see the scary result.
2: Transmission efficiency
Comparing two kind of telescopes and assuming the same opening and
focal length,
they are setup with a high quality corrector to make a astrograph of
it. Optimized for wide field deep sky. Just a relative comparing.
Also assume a monochrome camera with filter wheel to make rgb color images.
Note. Each lens or filter have two surfaces.
Each line is the contribution of efficiency.
| Refractor triplet |
Transmission |
Reflector Newton |
Transmission |
comments |
| |
|
|
|
|
| Photons input |
100% |
|
100% |
|
| |
|
|
|
|
| Lens |
98% |
Primary mirror |
92% |
|
| triplet |
98% |
|
|
|
| |
98% |
Secondary mirror |
92% |
|
| |
|
40% obstruction diameter |
84% |
|
| |
|
|
|
|
| Field flattener |
98% |
Coma corrector |
98% |
|
| 4 lenses |
98% |
4 lenses |
98% |
|
| |
98% |
|
98% |
|
| |
98% |
|
98% |
|
| |
|
|
|
|
| Filter |
98% |
Filter |
98% |
from filter wheel |
| |
|
|
|
|
| Camera |
98% |
|
98% |
Camera house |
| two protection |
98% |
|
98% |
Camera sensor |
| windows |
|
|
|
|
| |
|
|
|
|
| Total transmission |
82% |
Total transmission |
62% |
|
It doesn't look too bad, we have a throughput of about 82% of the photons in the refractor and 62% in the reflector.
Bit it's a bit worse, this was at the center of sensor, vignetting problems maybe will reduce it by half at the corners.
But is this the whole true story?
X . IIIIIIIII
Transmission on weapons
It has been said that outer space is the ultimate high ground for
military engagements, and if we examine orbital space-based weapon
platforms seen in sci-fi, it seems that our future will include orbital
space as a future battleground. Currently, orbital space is used by
military organizations and intelligence services for all manner of
satellites that watch and listen. But, could orbital space be
militarized? Could we have orbital artillery as predicted by science
fiction and the cancelled SDI program? In this blogpost of FWS, we will
be discussing orbital artillery and orbital bombardment.
The idea of the militarization of outer space was a real fear in the
heady days of the Space Race between the USA and USSR. The Soviets had
put up military space stations and a few of them were armed with an 23mm
cannon. There was also worry that the arms race would continue into the
void of outer space with orbital nuclear missile platforms. In 1967,
the United Nations passed the Outer Space Treaty that established legal
frameworks on the ownership of celestial bodies, like Luna and Mars. One
of the elements of the treaty was preventing orbital weapon platforms
that bore nuclear weapons and othe r WMDs. This treaty shaped the
research on orbital weapon systems.
The Types of Orbital Artillery
Directed Energy
One
of the most common type of orbital bombardment/artillery is directed
energy beams that can be used more like knife than an club or even a
shower of directed energy death-laser-beams that tear through the
planetary surface. Shooting freaking laser beams on the surface of Luna
is much easier than shooting them down to Earth or Mars, due to the
atmosphere. Any military-grade lethal DE beam would have to be powerful
enough to punch through the atmosphere and hit the target with enough
energy to be lethal. It is unlikely that lasers will be the orbital DEW
system of choice, instead, it is likely that particle beam DEWs would
fulfill that role. The use of DE is common in science fiction "kill
satellites" as seen in works like
Akira.
Kinetic Projectiles or "Rods from God"
Unlike orbiting nuclear weapons, kinetic projectiles are legal under the
1967 Outer Space Treaty (as well as space-based lasers) and instead of
those dirty nuclear weapons, these rods from god are able to delivery
some serious punch without the nasty after effects of nukes. If we
examine the USAF's proposed kinetic bombardment system, these six meter
long tungsten rods impacted the surface of the Earth with the road
going at MACH 10 (7,700 MPH). The impact of the rob was equal to between
10 and 120 tons of TNT, less than the 2,000 tons of TNT that the Fat
Man and Little Boy Atomic bombs produced when dropped on Japan. Unlike
long-range bombers like the B-52 and B-1, the tungsten rods at able to
reach their Earth-based target at between 10-15 minutes, and are
extremely difficult to intercept like ICBMs or bombers. While this form
of orbital artillery is not as effective as nuclear weapons, they can be
used in more of combat supporting role and even pre-invasion artillery
softening up operations, along with being a effective "bunker buster"
system. The data for this section, comes from the Game Theory video:
https://www.youtube.com/watch?v=rx5XyspHldk
Reentry Vehicle
On current ICBMs, re-entry vehicles are used to delivery the nuclear
payload safety through the atmosphere and blow the holy jesus out of
your enemy. This could be another way to delivery orbital artillery
rather than kinetic rods, especially at longer ranges than just orbital
space. Reentry vehicles could also pack more countermeasures than just
speed to defend themselves. While the RV would be good method of
delivering nuclear weapons and other WMDs, they would make for a poor
orbital artillery method.
Controlled Meteors
From the Centauri mass driver bombardment of Narn to the Fithp "foot"
being shot into the Indian Ocean by rocket motors, meteors have been an
excellent form of orbital bombardment, and the oldest...after all,
humans are only around due to an meteor strike. Some science fiction
works, like
Babylon 5 and
Starblazers space fleets use
controlled meteors and asteroids as a form of orbital bombardment.
However, this comes with certain risks...any space rock too big, and you
could completely wipe out all life on the planet along with the
ecosystem...unless that is your goal, then have at it, and bombing into
extinction!
The Dangers of Orbital Artillery/Bombardment
There is nothing more devastating to soldiers than when supporting
artillery from field guns to CAS goes wrong. Despite the advancement in
battlefield technology, artillery fire can go horribly wrong, and your
own forces pay the price. That is the danger today, and that will be a
danger tomorrow. Even in video games, nothing is worse than calling down
a strike and it wiping out friendly forces. If and when orbital based
weaponry becomes a reality, the risk of troops calling down artillery
could go horribly wrong, and given the power of rods-from-god, a
miscalculation by the director, and an entire city or taskforce could be
wiped out. Then there is another risk: overuse. Some orbital
bombardment systems have been projected in science fiction as pinpoint
laser DE beams able to slice-and-dice enemy tanks and infantry
formations. However, the reality is that kinetic bombardment systems
would be very powerful, and their overuse or misuse could bring about
massive destruction and even nuclear winter conditions. This applies
more so to the use of asteroids and meteors as a form of kinetic
bombardment, too much and you ruin the planetary ecosystem, and affect
global climate change.
Defense Against Orbital Weapon Platforms
Oddly, most military organizations and weapons manufacturers have
already put weapon systems into place to counter satellites and the
possibility of orbital based weapon platforms. The anti-satellite
missile that can be deployed from strike fighters like the American F-15
Eagle, or land based launcher systems, or even submarines/naval
vessels. These kinetic-kill warheads are fitted to small multi-stage
rockets have proven effective against satellites, and could be effective
against orbital weapons platforms as well. While an orbital weapon
system could be camouflaged as something else, the moment it began
firing, the game would be up, and ASAT weapon systems would be utilized.
Of course, one way around this could be the assumed role of the X-37B
USAF drone-shuttle: an mobile launcher system based around an space
plane design. In the end, one of the best defenses against orbital based
weapon platforms is wiping out their command & control system back
here on Earth. Whether by direct action, like we saw in
Call of Duty: GHOSTS or an EMP blast, any would be effective in taking out one method of controlling orbital weapon platforms.
Real-World Examples of Orbital Weapon System
The THOR Project (USA 1950's-today)
Boeing
in the 1950's became working on a kinetic bombardment system called
THOR. The idea was to have an orbital artillery system that could not
provoke a nuclear exchange, and THOR later would conform to the 1967
Outer Space Treaty. The heart of THOR was long tungsten rods that were
the size of telephone poles and could delivery a punch without the risks
of nuclear or conventional explosives. Even today, the US Air Force has
been continuing the work on THOR as late as 2003. While Project THOR is
technical possible, there are challenges with controlling the rod
through atmospheric reentry, the cost of putting the system in space,
the political heat for having orbital weapons system, and lastly,
maintenance. A massive military orbital weapons system would need
maintenance, and with the Space Shuttle fleet gone, it would require
something like what was seen in
COD: GHOSTS to keep the system running.
Fractional Orbital Bombardment System (USSR 1968-1983)
Leaving it to the Soviets...their space-based weapon system was known as
the Fractional Orbital Bombardment System, and basically was putting
nukes into space that would be waiting for the order to hit America.
Lovely. Th heart of the plan was to put ICBMs into low-orbit, and if the
call ever came, the missiles could avoid NORAD and could cut down on
flight times, hitting the USA before they could launch their nukes. Of
course, the plan is banned under the Outer Space Treaty and the SALT II
treaty. While the plan was never carried out, it did lead to Soviet
rocket developments, and the entire program was scrapped in 1983.
The Rumored X-37B Space Drone Orbital Weapon Delivery System
For years, there have been rumors of a "secret" space program with their
own Space Shuttles and even a space station. In 1999, NASA began the
X-37 robotic mini-shuttle program, and in 2004 the USAF took over the
project, and began flying the X-37B mini-shuttles on long-term missions
for reasons unknown. Recently, X-37B OTV-2 spent 469 days in space, also
for reasons unknown. There are some that believe that the X-37B robotic
space shuttle is an delivery system for orbital weaponry or an orbital
anti-satellite weapons platform that could be using kinetic-based
weaponry or even a laser to knock out or fry hostile satellites.
The 3rd Reich "Sun-Gun"
After the defeat of the 3rd Reich in 1945, the allies began to
understand the depth of the scientific knowledge of the Nazis and how
much they were pushing the envelope of technology. One of those projects
was an orbital weapon system called "Soonengewehr". The Sun-Gun called
for a massive 100 meter wide mirror that could focus the sun's light
into a directed energy beam that could target any portion of the Earth.
This would have orbited at 8,200 kilometers above the Earth, and would
have been constructed into portions by the stillborn Nazi space program.
The sun-gun would have been manned and possible used Nazi space
stations to help construction and maintenance. The Sun-Gun was seen as a
tool for 3rd Reich domination of the Earth and a way to keep themselves
in power for a 1,000 years. Of course, the allies began winning the
war, and after Operation: PAPERCLIP, the Americans felt that the Sun-Gun
would have never worked.
The Role of Orbital Artillery/Bombardment in Future Warfare
If humanity is able to escape to the stars and construct off-world
colonies and fleets of combat spaceships to protect them, orbital
bombardment will be a factor. If there is a armed contest over a settled
world, the invading force will need to support the planetary invasion
force going dirt-side. While it is likely that any invasion force would
carry means of heavy weapons support, the invaders would need time to
get the cannons from star-side to dirt-side, and time to setup the field
artillery along with any aerocraft.
This
is were the orbiting warship comes into play. Any planetary invasion
would be first conducted via control of orbital space, much like air
superiority. Once that condition has been met, the warships could soften
up the planetary defenses via some form of orbital artillery. That
could be kinetic rods-from-god or DE weaponry, but either way, the
weaponry of the warship would be used in a similar manner to the US Navy
using their battleships in World War II to shore bombard prior to an
ambitious invasion force landing. After the planetary LZ is secure, and
field artillery and CAS are being established, the orbiting warship
could be setting up so-called "kill-satellites" to further support the
ground forces. This Kill-Sats could be dual-role as well, supporting
ground planetary operations with support fire and protecting the planet
from any counter-strike.
From the Fox Mulder Corner...
One
of the most infamous video footage of UFOs (or something) in Earth
orbit being engaged by some type of weapon systems came from Space
Shuttle Orbiter
Discovery during STS-48 in September of 1991.
Some believe that the amazing footage shows an Earth anti-UFO defense
system being use, and missing the alien craft. Of course, NASA and
others claim it is ice particles. Even before this, there were claims
that the US maintains an orbital weapons system that was piggybacked on
the old SDI program. Why does the US military maintain an secret orbital
weaponry program. Aliens. Some believe that the US and other nations
are fighting a secret war with an alien intelligence.
Orbital Bombardment and Science Fiction
As with many elements in Sci-Fi, EE "Doc" Smith did it first, and this
includes orbital bombardment, but it would take the Cold War and the
Space Race for science fiction to develop orbital bombardment that was
more hard science based. Of course, human beings have been always seen
and experienced the power of meteors, and this common human fear is
linked to orbital bombardment. During the Cold War, the idea of orbital
weapon systems and asteroids-as-weapons took shape with Robert
Heinlein's
The Moon is a Harsh Mistress from 1966. Given the
popularity of that work, the idea of orbital bombardment entered more of
the minds of sci-fi creators. It also helped that during the Arms Race
and the Space Race, that Boeing was working on the rod-from-god Project:
THOR.
During
the 1980's, with the rise in science fiction and war gaming, and SDI;
orbital bombardment became a hot topic. This fueled a number of examples
in sci-fi, and one of the greatest lines fucking ever in a sci-fi film:
I say we take-off and nuke the site from orbit. It's the only way to be sure. In 1986's magnum opus,
ALIENS,
the idea of orbital bombardment was wrapped into one of the best lines
of the one of the best sci-fi movies of all time, and that triggered a
number of other sci-fi creators to include orbital weapon systems,
including nuclear, into their stories and creations.
This was especially true of anime and manga, as seen in
Gundam and
Space Cruiser Yamato, and later,
Bubblegum Crisis.
Today, orbital bombardment is common in science fiction works,
especially in the realm of video games. When video game technology
improved in the 1990's, creators could place more complex elements
graphically into the game, and one of those items was orbital
bombardment. Today, you can see examples in games like
HALO, Mass Effect, and of course,
Call of Duty: GHOSTS.
Examples:
The Attack on the Founder Homeworld from Star Trek: DS9
There are times when I respect the storylines and plots in
Star Trek,
and one that left an impression on me was the 3rd season 21st episode
called "The Die is Cast". In the 1995 episode, the Cardassian and
Romulan intelligence services unite for a clandestine mission to orbital
bombard the homeworld of the Founders, and attempt to end the threat of
the Dominion to the Alpha Quadrant once and for all. A small taskforce
of top-of-the-line warships from both powers arrived in the Omarian
Nebula, the location of the Founders' homeworld, and the seat of power
of the Domination. Also, their intelligence indicates that the Founder
homeworld is the main production site of the Jem'Hadar's life-giving
Ketracel White.
It
was hoped that this assault on the heart of the Dominion would produce
its collapse, however, the Battle of the Omerian Nebula was the result.
At first, the combined fleet was able to pound the homeworld with
torpedoes and directed energy fire, it seemed too easy, and that was
because the Founders learned of the plan, allowed to be carried forward,
and setup a trap for the combined fleet. The Founders left their world,
and allowed the fleet to destroy 30% of the planet's crust, and during
this moment, 150 Jem'Hadar warships descended on small attack force. It
was a slaughter, and wiped out the majority of these intelligence
services power and influence, allowing the Founders to have an easier
time subjugating the Cardassian Union and the Romulan Star Empire.
The Fithp Invasion of Earth from Footfall
One of my favorite sci-fi novels of all time is
Footfall by the
dream-team of Niven and Pournelle. The elephant-like alien race, the
Fithp. The Fithp are a young race from Alpha Centarui that used
technology and knowledge left by another species that shared their
world. The aliens construct a interstellar vessel and spend nearly a
hundred years traveling to Earth in cryo. The goal is conquest and
subjugation. Throughout the book, the Fithp use in-orbit lasers and
kinetic bombardment to soften up Earth for the invasion or just
surrender. When humanity uses nuclear weapons at the site of the Fithp
invasion in Kansas, the aliens responses with dropping a massive
asteroid into the Indian Ocean, nearly wiping out India, and allowing
for the aliens to control the bulk of Africa. Given the popularity of
the novel and that Pournelle worked on Project THOR,
Footfall would
influence a new generation of sci-fi creators to include some of the
concepts in the novel. If you have not read it, please do so...now.
The Covenant "Glassing" from the HALO Universe
It
just has to be said...the Covenant are just dicks. It is not enough for
them to destroy human colonies and kill everyone there, but then they
have to go and burn the world black with ship-mounted plasma artillery.
The massive plasma cannons on Covenant warships are altered to allow
them to project plasma in linear beams that hit the surface of a planet
with vastly intense heat, alter top soil to lechatelierite, a form of
silica glass. It takes the aliens days to glass an UNSC colonial world.
The world suffers global environmental damage that forever alters the
planetary environment and leaves the atmosphere in a state of nuclear
winter. Covenant glassing operations can be conducted from orbit or even
endo-atmospherically. It is believed from some footage from the end of
Reach, that the future UNSC has a slow method of reversing the effects of glassing.
The Zentraedi Holocaust from the ROBOTECH Universe
In the final battle in the First ROBOTECH War, the SDF-1, the UN Spacy
Forces, and the rebel Zentraedi forces under Breetai all attempt to
stand up against the invasion by the Zentraedi Central Fleet, and force
of 4.8 million warships. Supreme Commander Dolza fully intends to wipe
out humanity, the Earth, and the inflected rebel Zentaedi for good.
During the battle, the central fleet pounds Earth with laser and
particle beam fire that renders the surface of the planet a wasteland,
killing billions. While the central fleet was destroyed, by the SDF-1,
humanity was nearly wiped out. The Zentraedi Holocaust, as it was later
called, killed over 5 billion humans, and altered the course of the
species for all time. Only a few million survived, along with the
off-world human service-members, and the civilians of Macross.
The USAF ODIN and the Federation's LOKI Space Platforms from Call of Duty: GHOSTS
While fans and players of the
Call of Duty franchise were very unhappy with the online play of
Ghosts,
the campaign was rather solid, and had an original "Invasion USA"
storyline that involved real-world orbital kinetic bombardment by
hijacked USAF "roads from god" satellites by South American forces. The
ODIN Space Platforms, or
Orbital
Defense
Initiative were
satellite launcher platforms that fired six meter long tungsten rods
from orbital with great accuracy. When the Federation took control of
the ODIN space station, they bombarded main cities of the United States
as a prelude to their massive invasion. Only through the brave actions
of USAF personnel did the full might of ODIN was avoided.
To
finally end the US, the Federation takes survives elements of the ODIN
space station, and creates their own space-based weapon platform, LOKI.
Unlike ODIN, LOKI could be controlled by a ground based operations
center, the robds were smaller allowing for them to be used in a close
fire support role, and there were more platforms, allowing the
Federation to carryout further offensive operations. During the apex of
Ghosts,
the USAF space warfare team, LCARUS, mounted an assault on the
Federation LOKI space station, and turned the Federation's weapon
against them, wiping out the ground-based control center, and the
Federation naval force. LOKI was destroyed by the USAF LCARUS team. ODIN
and LOKI may be one of the most accurate real-world examples of
space-based weapons platforms in popular media.
The Centauri Mass Driver Bombardment of Narn from the B5 Universe
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During the Narn-Centauri of 2259, the superior Centauri Republic gained
the upper hand, and finally arrived at the homeworld of the Narn. When
the Narn refused to surrender, the Centauri did not mount an invasion of
the planet, but instead used retrofitted mass drivers on their
Primus class
battlecrusiers to propel asteroids. This form of planetary bombardment
is illegal and ban by the League of Non-aligned Worlds, but te Centauri
gave zero fucks, and did it anyway. For four days, the Centauri warships
bombarded the surface of Narn, and finally, the Narn government gave in
and surrendered to their former masters. Narn was already a world still
scarred by the Centauri strip-mining efforts during their occupation,
and the pounding from space didn't help. For over a year, Narn was a
world under a nuclear winter, and it would take over ten years with the
help of Minbari atmospheric processors to clean most of the air.
Here is the dialog from the episode:
Londo Mollari:
Refa, any force attempting to invade Narn would be up to its neck in blood—its own!
Lord Refa:
We have no intention of invading
Narn. Flattening it, yes—but invading it? We will be using mass
drivers. By the time we are done their cities will be in ruins, we can
move in at our leisure!
Londo Mollari:
Mass drivers? They have been outlawed by every civilized planet!
Orbital Bombardment from DUST 514
In the EVE Online military sci-fi shooter,
DUST 514,
players can call down three types of orbital strikes as fire support
and even turning the tide in the online gaming arena. The first type of
orbital strike is the Pulse Laser Strike that fires a high damage laser
beam, but it only covers a small area. Next is the EM strike that used
electro-magnetic energy blast to strike an larger area, but is a
non-lethal strike, bring down shields and electronics. Lastly, there is
the Hybrid Strike that combines lasers and other times of ammunition
that the most devastating. Of course, giving the offensive power of the
orbital strike, it is harder to achieve battlefield reward.
The Lunar Catapult from The Moon is a Harsh Mistress
Robert A. Heinlein's famous 1966 book is often praised, cited, and still
read today, and does have a kick ass title...but, I've never liked it.
I've read it several times to see what the fuss is all about, but much
like
Starship Troopers, Heinlein seems to suck the excitement and
joy out of the basic plot. However, I do respect some of the themes,
ideas, and of course, TANSTAAFL. In 2075, Lunar colonies are populated
by the unwanted of Terran society, and computer technician Manuel Garcia
befriends the Lunar colony computer system, HOLMES-IV. Due to Earth's
demands, and the limited resources on the Lunar colonies, the export of
wheat from Luna to Terra must be stopped, or less the Lunar colonies
will descent into madness and cannibalism. Lovely. The computer, Manuel,
and others in the Lunar liberation movement use the catapult launcher
system to throw large lunar rocks at unpopulated areas of Earth,
resulting in kinetic bombardment terrorism. The effort is successful,
and Lunar becomes a free republic. Some falsely believe that
The Moon is a Harsh Mistress to be the first real example of orbital bombardment in sci-fi, however E.E. "Doc" Smith takes that cake.
The Xindi Probe Attack from Star Trek: Enterprise "The Expanse"
In the opening to the 3rd Season of much maligned
Star Trek series
Enterprise,
the Xindi use an sphere-shaped weapons probe to test the design for
their "super-weapon" that was designed to destroy the Earth. This
one-man probe was a scaled-down prototype of the larger planet-killer
particle cannon, and was designed to real-world test the weapon against
conditions on Earth. While smaller, this particle beam sliced a canyon
from Florida to Venezuela, killing seven million. This fuels the
Federation and the Earth Military to rearm the NX-01, and sent on a hunt
for the Xindi.
The USSD Particle Satellites from Bubblegun Crisis: 2033
The United Nations Strategic Space Defense Force of USSD is a branch of
the United Nations has a network of 200 of these Kill-Sats, the VA-61
that are constructed around a particle beam emitter that has the
destructive power to scar 100,000 miles. The role of the USDD is to
enforce global peace, but some have been able to hack into the
satillites, and use them for their own purposes, namely the evil
megacorporation of Genom. Genom helped developed the "killer doll"
Boomer project for the USSD, as a ground-to-space link to help target
their kill-sats on more of a pinpoint target.
The Slug's Rod Attacks from Orphanage by Robet Buettner
In the excellent first novel by author Robert Buettner,
Orphanage,
the world had moved away from war, until the kinetic rods began
dropping onto the Earth from Joviah moon of Ganymede. These aliens,
called Slugs, are an advanced alien race very different from mankind,
and their goal is to soften up Earth by using massive kinetic manned
rods from Ganyeme. Earth quickly becomes a mess, cities are gone,
economies are a wreck, and there are orphans...lots of orphans. Some
rods are intercepted by armed space shuttles, but most get through.
Earth is near collapse, and a despite plan is put into action,
orphan-soldiers using old equipment and a advanced warship travel to
Ganymede and assault the Slugs at their homebase. The destruction of the
Earth by the alien rod attacks are nice touch and how it effects all
levels of society. If you have not read
Orphanage by Robert Buettner, than do so. This one great military science fiction book!
The Hammer of the Dawn from the Gears of War Universe
One of the more famous orbital bombardment systems in modern video games
is the Hammer of the Dawn. The Dawn is an Imusion-powered laser DEW
platform, developed by the COG during the Pendulum Wars, prior to the
Locust invasion. During the Locust Wars, the Hammer of the Dawn became
key to supporting COG missions and was used to destroy much of the
surface of Sera. While the Dawn was extremely effective, it also took
forever to boot up, and it was out of range more than it was in range.
The games never make mention on how many Hammer of the Dawn satellites
there are, but by the 3rd
Gears of War game, the Dawn Kill-Sats were breaking down and taxed by overuse.
The AEGIS Orbital Defense Platforms from Babylon 5 "Endgame"
In
the final showdown between the forces loyal to dickhead President Clark
and B5's liberation force, Clark was losing and decided to turn the
planetary defense grid of orbital weapons platforms called AEGIS back
onto Earth. AEGIS platforms were equiped with missiles and heavy-duty
particle cannons that could level wide areas of the surface. The
liberation fleet destroys the AEGIS platforms and saves 40% of Earth's
population from certain death. The AEGIS defense grid is rebuilt just in
time for the Drakh attack on Earth in 2266.
The SOL Weapon Platforms from Akira
In the landmark manga and anime work
Akira, there is an directed-energy orbital weapons platform called SOL or
Satellite
Orbital
Laser.
This large orbital weapons platform was developed by the Japanese for
World War III. This was seen in the anime, and the American laser
satellite called FLOYD was seen in the manga. During the end battle
between Tetuso and the whole of Neo-Tokyo, the SOL is used for an
attempted assassination of Tetuso, and the SOL first projects a aiming
beam that focuses to an DEW beam of some power. The SOL was destroyed
by Tetuso in the
Akira anime. Given the number of the SOL platform seen in
Akira, 740, there is a possibility of more SOLs.
The Alien Relativistic Missiles from The Killing Star
One of the saddest books about alien contact is 1995's
The Killing Star. A
swarm of relativistic missiles from an alien intelligence hit Earth
hard, killing the bulk of humanity in the first strike that rates as an
extinction level event. Only because a few humans were off-world, could
complete extinction be avoided, plus the aliens' took one male and one
female human for their zoo, and the squid-like aliens tell the humans
that once humanity was about to master relativistic travel, than they
were a threat to them. The concepts in the novel are hard science
fiction and this book rates among my favorites. It is such a sad story
though.
Imperial of Man's "Exterminates" from WH40K
There several methods that are used by the Imperial Navy to attack and
overwhelmingly assault the surface of a planet. This order is called
"Exterminates", and the shipboard weaponry of the Imperial warship can
be used, along with virus bombs and cyclonic tropodes. Few sci-fi works
have ever shown the level of death assoicated with orbital bombardment
than
WH40K. Exterminates is used through the various
WH40K media, from books, video games, and the RPG. I became aware of orbital bombardment from the older PS2
WH40K video game
Fire Warrior.
The Nerve Gas Orbital Modules from Moonraker
In the outlandish bat-shit crazy 1979 Bond film
Moonraker,
humanity was nearly wiped out by evildoer Drax and his nerve gas orbital
bombardment. In the film, evil genius Drax of Drax Industries plans on
wiping out all life on Terra by using nerve gas orbital module deployed
from his space habitat station. Once human life is gone, Drax and his
handpicked colonies will reseed Earth and Drax will become supreme ruler
of the new human race. Of course, James Bond and Holly Goodhead take to
an orange and white space shuttle and stop his evil plans. It is
believed that
Call of Duty: Ghosts used some of
Moonraker for
their own orbital space combat scenes. This marks on of the few times
FWS as ever talked about James Bond, despite me being a huge fan of the
Bond films.
HERCULES and PETER the GREAT from Meteor (1979)
In
the much panned 1979 disaster film, a massive asteroid is headed to
Earth that will produce an extinction level event, and there seems to be
little to stop it. But wait! The United States and the USSR both have
secret nuclear weapon platforms that completely volatile the Outer Space
Treaty. In the film, Sean Connery was the developer of the American
HERCULES weapon platform, he is brought on to help with redirecting the
asteroid from hitting the Earth and killing everyone. The Soviets have
the PETER the GREAT nuclear weapon platform.
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