Apa-an sih Combi Brake itu?

Combi Brake adalah suatu teknologi mekanis untuk mendistribusikan kekuatan pengereman antara roda depan dan roda belakang dengan hanya menekan satu tuas rem sebelah kiri saja.

Dengan teknologi Combi Brake ini, sepeda motor akan berhenti dengan jarak pengereman yang lebih pendek secara lebih maksimal dengan pengereman yang merata pada kedua roda depan dan belakang secara bersama-sama. Intinya Bobot kekuatan pengereman akan terbagi secara otomatis antara roda depan dan belakang sesuai kebutuhan pengereman pada motor.

Nah Combi Brake ini sangat cocok digunakan oleh pengendara pemula maupun kaum hawa. Dimana dengan adanya teknologi Combi Brake ini akan membantu pengendara pemula untuk melakukan pengereman layaknya pengendara motor yang sudah Pro. Combi Brake akan mengambil alih kemampuan pengendara yang pro pada saat melakukan distribusi pengereman pada roda depan dan belakang, sehingga pengendara pemula-pun akan sangat terbantu oleh Combi Brake.

Bagaimana cara Combi Brake bekerja ?

Ketika tuas rem kiri (1) ditekan, maka equalizer gaya akan bekerja untuk mendistribusikan tenaga tekanan tadi menjadi dua; yang satu menuju rem pada roda belakang (2) yang satunya lagi menuju ke tuas ungkit (3) untuk menekan knocker yang akan menekan piston hidrolik (4) yang tentu saja akan bereaksi untuk mengaktifkan rem cakram depan. Pada proses ini power pengereman akan terbagi secara otomatis pada kedua roda depan dan belakang.

Nah Intinya justru ada di mekanisme Equalizer yang akan mendistribusikan gaya berdasarkan momen gaya akibat adanya perbedaan panjang lengan tuas kabel di equlizer.

Dengan segala kelebihan Combi Brake tadi, apakah lantas Combi Brake sangat ampuh dan tidak memiliki kekurangan sama sekali? tentu saja tetap ada kelemahannya, yaitu penyetelan rem belakang (drum brake) yang harus bener-benar PAS agar Combi Brake dapat benar-benar bekerja dengan baik.

Nah, jika di Thailand motor Matic Honda sudah menggunakan Combi Brake mengapa justru motor Matic Honda Indonesia tidak ada yang mengadopsi sistem yang bagus ini?

Apa alasan AHM melepas fitur ini pada motor Matic Honda yang beredar di Indonesia? Pertama mungkin alasan menekan harga. Kedua mungkin AHM menganggap biker-biker di Indonesia sudah dianggap canggih dan Pro, jadi gak perlu lagi perlindungan sistem pengereman yang canggih ini lagi.

Kalau masih belum puas dengan kedua jawaban di atas, mari kita bikin Combi Brake sendiri aja setelah tahu cara kerjanya. gampang kok!!! Bahkan bisa diterapin di Vario, Beat, maupun product matic di luar Honda macam Mio, Soul, Spin dan Sky-Wave.

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Did an ice age boost human brain size?

• 29 July 2009 by Bob Holmes
• Magazine issue 2719. Subscribe and get 4 free issues.
• For similar stories, visit the The Human Brain , Evolution and Human Evolution Topic Guides

IT IS one of the biggest mysteries in human evolution. Why did we humans evolve such big brains, making us the unrivalled rulers of the world?

Some 2.5 million years ago, our ancestors' brains expanded from a mere 600 cubic centimetres to about a litre. Two new studies suggest it is no fluke that this brain boom coincided with the onset of an ice age. Cooler heads, it seems, allowed ancient human brains to let off steam and grow.

For all its advantages, the modern human brain is a huge energy glutton, accounting for nearly half of our resting metabolic rate. About a decade ago, biologists David Schwartzman and George Middendorf of Howard University in Washington DC hypothesised that our modern brain could not have evolved until the Quaternary ice age started, about 2.5 million years ago. They reckoned such a large brain would have generated heat faster than it could dissipate it in the warmer climate of earlier times, but they lacked evidence to back their hypothesis.

Now hints of that evidence are beginning to emerge. Climate researcher Axel Kleidon of the Max Planck Institute for Biogeochemistry in Jena, Germany, modelled present-day temperature, humidity and wind conditions around the world using an Earth-systems computer model. He used these factors to predict the maximum rate at which a modern human brain can lose heat in different regions. He found that, even today, the ability to dissipate heat should restrict the activity of people in many tropical regions (Climatic Change, vol 95, p 405).

If keeping cool is a problem now, Kleidon says, it would have been even more challenging - perhaps too challenging - 2 or 3 million years ago when temperatures were a few degrees warmer than today and air-conditioning units were harder to come by.

A new study by Schwartzman and Middendorf suggests that a small drop in global temperatures may have made a big difference. The pair used basic equations of heat loss to estimate how fast the small-brained Homo habilis would have been able to cool off. Assuming overheating limited the size of H. habilis's brain, they then calculated what drop in air temperature would have been needed for Homo erectus to be able to support its bigger brain (see diagram). They found that a drop in air temperature of just 1.5 °C would have done the trick (Climatic Change, vol 95, p 439).

Given the timescales involved, it may be near-impossible to match definitively the onset of an ice age with speciation, but a 1.5 °C drop is consistent with the cooling climate of the time, says Middendorf.

"In principle, I'm receptive to the hypothesis," says Dean Falk, a palaeoanthropologist at Florida State University in Tallahassee, "but I need the data." She says that if measurements showed that people living in tropical countries today have smaller brains relative to their body size than people in temperate climates, this would go against expectation and lend support to Kleidon's model.

Being able to cool bigger brains can only be part of the story, however. It would have lifted the brakes on expansion, says psychologist David Geary at the University of Missouri in Columbia, but there has to be something driving the increase.

Over the years, researchers have come up with three broad reasons why bigger brains might have been advantageous: to give their owners the ability to cope with changing climates by exploiting technologies such as shelter, fire and clothing; to deal with the cognitive demands of hunting and gathering; or to help people outsmart their neighbours.

To help narrow this down, Geary collected data from 175 fossil hominin skulls, from 1.9 million to 10,000 years old. Then he looked to see whether brain size was best correlated with climatic variability - a crude measure of biodiversity which could indicate the complexity of hunting and gathering - or the human population size at the time, which could reflect the complexity of social interactions.

Geary's analysis found that population size was the best predictor of brain size, suggesting that our ancestors' need to outcompete their neighbours in order to survive may have been the strongest driver of brain growth (Human Nature, vol 20, p 67).

The case is far from closed - Geary's study does not demonstrate cause and effect, for one thing - but the picture beginning to emerge suggests that an ice age set the stage for a socially driven brain boom. And from that time on, it was the brainiacs who stole the show.

Warming Arctic could teem with life by 2030

"Teeming with life" may not be the description that springs to mind when thinking of the Arctic Ocean, but that could soon change as global warming removes the region's icy lid.

A study of what the Arctic looked like just before dinosaurs were wiped off the planet has provided a glimpse of what could be to come within decades.

Alan Kemp of the UK National Oceanography Centre in Southampton and colleagues used powerful microscopes to inspect cores of mud extracted from the bottom of the Arctic Ocean. They found successive layers of tiny algae called diatoms. The pattern of the layers and the distribution of the diatoms provides strong evidence that the Arctic was free of ice during the summer and, contrary to recent studies, frequently covered in ice during the winter.

Hot summer

Ice-free summers and icy winters are precisely what glaciologists fear could happen in the Arctic within decades. Over the past few years, wind pattern and warm temperatures have been gradually thinning Arctic sea ice, making it less and less likely to survive the summer. Some believe the Arctic could be ice-free during the summer as soon as 2030.

The researchers say that the sheer number of diatoms locked in the mud suggests that when the dinosaurs roamed the Earth the Arctic Ocean was biologically very rich during the summer, on a par with the most productive regions of the Southern Ocean today. Since diatoms are at the very bottom of the food chain, waters rich in diatoms can support a lot of larger life forms as well.

"On the basis of our findings, we can say that it is likely that a future Arctic Ocean free of summer sea ice will also be highly productive," says Kemp. Arctic fauna today is limited by the region's harsh conditions. The ocean is home to very few species of fish – such as the Arctic cod – which in turn support seals, whales and polar bears.

Summer migration

While more diatoms during the summer does not mean that larger animals will spontaneously appear in the Arctic over the coming decades, it could give species that currently live further south an incentive to move into the region by providing them with food. The most likely scenario is one in which larger species migrate to the Arctic in the summer to feed on the enriched summer food chain, then move back south during the dark winters.

"The outcome would depend on organisms at all levels of the food chain moving in to exploit this potential," says Kemp. "What is unpredictable is what species from elsewhere may migrate in to fill the new ecological niches."

A study of fossils and fossilised faeces carried out around Devon Island in the Canadian Arctic, suggested last year that the regions may once have been home to a rich gathering of larger fish and possibly even sharks during the late Cretaceous (Proceedings of the Royal Society B, DOI: 10.1098/rspb.2008.0801). Presumably, these animals would have been supported by Kemp's diatoms.

Journal reference: Nature (DOI: 10.1038/nature08141)

Shocking cancer treatment may also yield weapon

A technique thought to be a promising cancer treatment is also being investigated as the basis for a Taser-like weapon that stuns for longer, New Scientist has learned.

The technology involves short, nanosecond-long pulses of extreme voltage.

Microsecond pulses have been used for years to punch temporary holes in cell membranes, to shove genes or drugs into cells. But the nanosecond pulses have similar effects on individual organelles inside a cell, such as the nucleus.

For reasons as yet unknown, this can cause a cell to destroy itself in a process known as apoptosis, something being investigated as a cancer treatment. But the nanosecond pulses are also being researched as a way to temporarily disable human muscles.

Incapacitating effects

Much research to date on nanosecond pulses has come from the Frank Reidy Research Centre for Bioelectrics at Old Dominion University in Norfolk, Virginia, where some research is sponsored by the Pentagon's Joint Non-Lethal Weapons Directorate (JNLWD) of Quantico, Virginia.

"Efforts are ongoing as part of our Human Electro-Muscular Incapacitation bio-effects research," confirms David B Law, technology division chief at the JNLWD.

"The short-pulse simulations and research appear to be demonstrating a degree of voluntary muscular impairment or inhibition, that remains in effect for durations longer than the exposure period," he adds.

Existing Taser use multiple electric shocks of a few microseconds over a five-second cycle. The shocks are delivered to the body through twin electrodes fired in a dart.

The pulsing electric field created inside the body disrupts the electrical activity of nerve cell membranes. These are responsible for carrying instructions and feedback around the body.

The effects wear off almost immediately, according to Taser spokesman Steve Tuttle, so that a suspect is incapacitated for just long enough to make an arrest.

Stunned for longer

Even shorter, nanosecond pulses have the potential to cause similar but longer lasting stunning, research from the Frank Reidy centre suggests.

One study on cells in vitro indicated that 60-nanosecond pulses caused "profound and long-lasting loss" of the electrical activity in the membranes of cells similar to nerve cells. The effect lasted fifteen minutes.

So far, research investigating the potential to disable muscles using nanopulses has been limited to tests on tissue samples in vitro and theoretical studies that claim the ultrashort shocks should be able to disable a whole animal.

However, Law says that plans for testing on live subjects are "proceeding at appropriate institutions." He declined to be more specific or say when human testing might take place.

"The medical and biological effects of such ultra-short electrical shocks in such a weapon are presently unknown," highlights Amnesty International researcher Angela Wright, saying the organisation is already concerned that evidence is emerging that Tasers and other shock devices have long-term health effects.

She thinks that the different effects of even shorter pulses may also have unpredicted effects.

-Source from newscientist-

Obama_cadillac_limo

General Motors has once again built the First Limo, which isn't so much a car as an armored personnel carrier wrapped in Cadillac bodywork. It is code-named "Stagecoach" but given its weight, wheelbase and bunker-like level of protection, Caddy One has been nicknamed "the Beast."

The limo that carries President Obama down Pennsylvania Avenue to the White House today is the latest in a long line of Cadillacs to join the First Fleet over the years. Although GM and the Secret Service jealously guard the vehicle's specs and secrets, you can bet Obama's ride is the toughest, most sophisticated car anywhere. Think of it as the road-going equivalent to Air Force One.

"Although many of the vehicle's security enhancements cannot be discussed, it is safe to say that this car's security and coded communications systems make it the most technologically advanced protection vehicle in the world," Nicholas Trotta, assistant director for the Secret Service Office of Protective Operations, said in a statement (.pdf).

GM had even less to say, noting "one of the specifications is we don't talk about the specifications." But spokesman David Caldwell says the redesigned car "is a fresh, more modern, more expensive" version of the Cadillac DTS that has carried President Bush since his second inauguration in 2005. Obama's car, he says, is "a little bit more vibrant, if you will."

Even if no one's got anything to say about what's under all that armor, there are some things widely believed to be known about Caddy One's security measures.

The car is one of a small fleet of what is believed to be no more than 25 presidential limos General Motors built for the Obama administration, according to the Detroit News. Although presidential limos have a lifespan of about a decade, the Commander in Chief gets a new one about every four years. Hand-me-downs are used to carry the vice president and visiting heads of state.

GM says the car occupies the "same footprint" as the current presidential ride, but it is a little taller and the windows a little bigger to improve visibility. Limo One is believed to weigh between seven and eight tons, and spy shots suggest it rides on a GM medium-duty truck chassis propelled by a diesel engine. The body is sheathed in military-grade armor as much as 8 inches thick on the doors (each of which weighs as much as the cabin door on a Boeing 747, Motor Authority says). The armor reportedly is a mix of dual-hardness steel, aluminum, titanium and ceramic. The windows are ballistic glass said to be 5 inches thick, and Dan Neil of the Los Angeles Times says there's probably a woven Kevlar mat covering the floorboard to protect the car from blasts. The cabin is believed to feature a sealed air recirculation system to protect its occupants from chemical attacks.

"I think he will be surprised about how when he's in the limo, it's a cocoon," Joe Funk, a retired Secret Service agent who served as President Clinton's driver, told CNN. "The everyday noises will be gone, and he will be totally isolated in this protective envelope.

Still, despite being at least as secure as a hardened missile silo, GM says Caddy One features the same hand-sewn leather interior you'd find in the CTS at your local dealership, and supposedly it's got a 10-disc CD player. And, of course, it's packed with the latest communications technology.

"I think he will be surprised at the communication capabilities, how the phones, the satellites, the Internet - everything is at his fingertips," Funk said. "So at one end, you are totally removed from society. The other side of the coin is that he can have any communications worldwide at a moment's touch."

Obama's limo is the latest in long line of presidential cars Cadillac has built in the 100 years since Congress approved funding for a presidential motor pool. President Wilson rode in a Caddy during a parade marking the end of World War I. President Coolidge sported a lavish 1928 Cadillac Town Car, which was among the first Caddys parked at 1600 Pennsylvania Ave. It featured a 341 cubic inch engine and a robust (for the time) 90 horsepower.

In 1938, the US government received two Cadillac convertibles, each 21.5 feet long and weighing nearly 8,000 pounds. They were dubbed the "Queen Elizabeth" and the "Queen Mary" after the ocean liners. Each featured back-up generators, two-way radios and an arsenal of weapons. They served presidents Roosevelt, Truman and Eisenhower and were replaced by the Queen Elizabeth II and Queen Mary II, which remained in service until 1968.

Cadillac returned to the White House in 1983, when President Reagan rode around in a Fleetwood famous for being the last equipped with the Turbo Hydra-Matic 400 3-speed automatic transmission. President Clinton rode in a Fleetwood Brougham powered by a 454 cubic inch (7.4 liter) V8.

The largest collection of presidential limos is held by the Henry Ford Museum, but President Bush's limo will not appear in it. The Secret Service has since the terror attacks of Sept. 11, 2001, required that presidential limos be destroyed upon retirement to preserve their secrets.

Photo: General Motors.