amudu

Monday, May 9, 2011

Green School in Bali

Welcome to the green school in Bali, Indonesia. It provides its students with an education about the amazing environment that we live in. It is a holistic and relevant education. During the construction, only bamboo, elephant grass and clay were used. Cement was used just in some places in the foundation. The central and the most important building is the "heart of the school." It is perhaps the largest building in the world built entirely from bamboo. Its dimensions are 18 meters high and 64 meters long. General area of the school includes a variety of structures: apartment buildings, classrooms, office building, and cafes. The school gets electricity from environmentally friendly sources of energy: hydraulic turbine generators and installed solar panels. It seems that considering the way we are polluting the earth, everyone should attend.

Sunday, May 8, 2011

How Three-Dimensional Transistors Went from Lab to Fab

In Intel’s new design the silicon channel is raised like a fin, so that the gate contacts it from three sides. (Large graphic next page.)
Credit: Technology Review

Multimedia

Computing

How Three-Dimensional Transistors Went from Lab to Fab

Intel's new three-dimensional transistor design, announced early this week, is the culmination of more than a decade of research and development work that began in a lab at the University of California, Berkeley in 1999.
The 22-nanometer transistors, which Intel says will make chips 37 percent faster and half as power hungry, will be used for every element on the company's 22-nanometer scale chips, including both the logic and memory circuits. Processors that use the "tri-gate" transistors have been demonstrated in working systems, and the company will begin volume production in the second half of this year. It's unclear just how device-makers will take advantage of the chips, but they're likely to enable improved battery life and greater sophistication for portable devices, as well as faster processing for desktops and servers.
Intel turned to the new design because existing designs have begun running up against a performance roadblock. Conventional transistors are made up of a metal structure called a gate that's mounted on top of a flat channel of silicon. The gate controls the flow of current through the channel from a source electrode to a drain electrode. With every generation of chips, the channel has gotten smaller and smaller, enabling companies like Intel to make faster chips by packing in more transistors. But it has become more difficult for the gate to fully cut off the flow of current. Leaky transistors that don't turn off completely waste power.
The tri-gate transistors use rectangular silicon channels that stick up from the surface of the chip, allowing the gate to contact the channel on three sides, instead of just one. This more intimate contact means the gate can turn the transistor off nearly completely even at the 22-nanometer scale, which is responsible for the energy-efficiency gains in Intel's new chips. It's also possible to make tri-gate transistors with more than one silicon channel connected to each gate in order to increase the amount of current that can flow through each transistor, enabling higher performance.

Intel didn't invent this transistor design, but the company is the first to get it into production. If the company had stuck with planar transistors in the move from 32- to 22-nanometer transistors, the chips would have demonstrated 20 to 30 percent gains in efficiency and performance, says industry analyst Linley Gwennap. There had been speculation that the company would use the new transistor design for memory elements and not logic, and so not completely eliminate the planar transistors. By using the tri-gate technology for both memory and logic, says Gwennap, "Intel is really surging for the fences and seeing a large improvement in performance, which could be a huge advantage" over its competitors.

More Power from Rooftop Solar

Dark Mirror: Solar panels (with silver lines) are paired with reflectors (the solid dark material) to increase the amount of power a rooftop array can generate.
Credit: TenKsolar

Energy

More Power from Rooftop Solar

A startup called TenKsolar, based in Minneapolis, says it can increase the amount of solar power generated on rooftops by 25 to 50 percent, and also reduce the overall cost of solar power by changing the way solar cells are wired together and adding inexpensive reflectors to gather more light.
TenKsolar says its systems can produce power for as little as eight cents a kilowatt-hour in sunny locations. That's significantly more expensive than electricity from typical coal or natural-gas power plants, but it is less than the average price of electricity in the United States.
Solar cells have become more efficient in recent years, but much of the improvement has gone to waste because of the way solar cells are put together in solar panels, the way the panels are wired together, and the way the electricity is converted into AC power for use in homes or on the grid. Typically, the power output from a string of solar cells is limited by the lowest-performing cell. So if a shadow falls on just one cell in a panel, the power output of the whole system drops dramatically. And failure at any point in the string can shut down the whole system.
TenKsolar has opted for a more complex wiring system—inspired by a reliable type of computer memory known as RAID (for "redundant array of independent disks"), in which hard disks are connected in ways that maintain performance even if some fail. TenKsolar's design allows current to take many different paths through a solar-panel array, thus avoiding bottlenecks at low-performing cells and making it possible to extract far more of the electricity that the cells produce.

The wiring also makes it practical to attach reflectors to solar panels to gather more light. When solar panels are installed on flat roofs, they're typically mounted on racks that angle them toward the sun, and spaced apart to keep them from shading each other over the course of the day. Reflectors increase the amount of light that hits a solar array, but they reflect the sunlight unevenly. So in a conventional solar array, the output is limited by the cell receiving the least amount of reflected light. The new system can capture all the energy from the extra, reflected light. "The small added cost we put in on the electronics is paid back, plus a bunch, from the fact that we basically take in all of this reflected light," says Dallas Meyer, founder and president of TenKsolar. "We've architected a system that's completely redundant from the cell down to the inverter," he says. "If anything fails in the system, it basically has very low impact on the power production of the array."
The reflectors use a film made by 3M that reflects only selected wavelengths of light, reducing visible glare. The material also reflects less infrared light, which can overheat a solar panel and reduce its performance.
Meyer says the system costs about the same as those made by Chinese manufacturers but produces about 50 percent more power for a given roof area. Power output is about 25 percent higher than from the more expensive, high-performance systems made by SunPower, he says.
The new wiring approach does have a drawback: because it's new, the banks that finance solar-power installations may have doubts that the system will last for the duration of the warranty, and this could complicate financing, says Travis Bradford, an industry analyst and president of the Prometheus Institute for Sustainable Development.
TenKSolar, which has so far raised $11 million in venture funding and has the capacity to produce 10 to 12 megawatts of systems a year, is working on partnerships with larger companies to help provide financial backing for guarantees of its products.

Salty Solution for Energy Generation

Saline solution: This device generates electricity using differences in salinity between fresh and salt water. The two foil-like structures serve as positive and negative electrodes; the glass bulb is a reference electrode.
Credit: Yi Cui

Energy

Salty Solution for Energy Generation

Battery draws power from salinity difference between freshwater and saltwater.

The difference in salinity between freshwater and saltwater holds promise as a large source of renewable energy. Energy is required to desalinate water, and running the process in reverse can generate energy. Now a novel approach based on a conventional battery design that uses nanomaterials could provide a way to harvest that energy economically.
The new device, developed by researchers at Stanford University, consists of an electrode that attracts positive sodium ions and one that attracts negative chlorine ions. When the electrodes are immersed in saltwater, they draw sodium and chlorine ions from the water, and the movement of the ions creates an electrical current. The electrodes are recharged by draining the saltwater, replacing it with freshwater, and applying a relatively low-voltage electrical current, which draws the ions back out of the electrodes. When the freshwater is drained, the electrodes are ready to attract more ions from the next batch of saltwater.
"It is the opposite process of water desalination, where you put in energy and try to generate freshwater and more concentrated saltwater," says Yi Cui, a materials science and engineering professor at Stanford University and the study's lead author. "Here you start with freshwater and concentrated saltwater, and then you generate energy."
Cui's group converted to electricity 74 percent of the potential energy that exists between saltwater and freshwater, with no decline in performance over 100 cycles. Placing the electrodes closer together, Cui says, could allow the battery to achieve 85 percent efficiency.

A power plant using this technology would be based near a river delta where freshwater meets the sea. Drawing 50 cubic meters of river water per second, Cui says, a power plant could produce up to 100 megawatts of power. He calculates that if all of the freshwater from all of the world's coastal rivers were harnessed, his salinity-gradient process could generate 2 terawatts, or approximately 13 percent of the energy currently used around the world.
Such wide-scale use, however, would seriously disturb sensitive aquatic environments. "I think you would only be able to utilize a very small fraction of this or it would be an ecological disaster," says Menachem Elimelech, director of the Environmental Engineering Program at Yale University. Elimelech says it would be necessary to pretreat the water to remove suspended material including living organisms. Such processing would require energy, add costs, and itself seriously disturb the ecosystem if done on a large scale.

A Cancer-Fighting Implant

Cancer killer: A cross section of a polymer matrix designed to prime the immune system against cancer. Immune cells crawl through the pores and are activated by chemical signals and tumor molecules.
Credit: Edward Doherty, Omar Ali and Microvision Labs

Biomedicine

A Cancer-Fighting Implant

In a new approach to fighting cancer, scientists from Harvard University have engineered an implantable disc designed to attract immune cells and prep them to attack tumors. Mice with melanoma tumors were much more likely to survive if they'd been implanted with the device, and tumors disappeared in up to half of the vaccinated animals, according to research published today in the journal Science Translational Medicine. Researchers believe that the implant elicits a broader immune response than traditional vaccines, and may therefore prove more effective. A startup called InCytu, based in Lincoln, RI, is now developing the technology for human testing.
A number of vaccines for treating different types of cancer are currently being tested in clinical trials, though none has yet been approved by the U.S. Food and Drug Administration. Unlike traditional vaccines, therapeutic cancer vaccines are designed to halt or reverse the course of the disease after it has developed. Gardasil, Merck's vaccine against the human papillomavirus, is considered a preventative cancer vaccine and acts in a similar way to traditional vaccines. It helps prevent the development of cervical cancer by stopping viral infection--but it cannot treat existing cervical cancer.
While cancer vaccines come in several variations, the general approach is to trigger the immune system to recognize and destroy cells bearing a cancer-specific marker. The immune system can be tuned to cancer cells by injecting patients with specific molecules linked to different types of cancer, or by injecting irradiated cancer cells. Scientists have also tried to enhance this process by training the immune cells in a controlled environment outside the body--the cells are isolated from the patient's blood and exposed to cancer-specific molecules. The primed immune cells are then injected back into the patient, where they travel to the lymph nodes and trigger an immune response against the cancer.

However, a problem with this approach is that few cells survive the transplant process, making it difficult for the lymph nodes to mount a strong immune response. David Mooney and colleagues at Harvard University have developed an approach that allows this carefully controlled immune training to take place inside the body. A polymer scaffold, made of the same material used in biodegradable sutures and other surgical products, is impregnated with cytokines, signaling molecules produced by the immune system that attract immune cells known as dendritic cells."The cytokines diffuse into the tissue and the [dendritic] cells follow the gradient to the material and crawl right into it," says Mooney.

A Vaccine Offers Instant Immunity

Credit: Technology Review

Biomedicine

The body's immune system is often likened to an army, and vaccines to training exercises that build up defenses against pathogens. By exposing the immune system to inactive forms of a virus or bacteria, a vaccine trains antibodies to fight off a real pathogen in the event of an invasion. However, while vaccines prepare antibodies to identify an attacker, they often don't give specific instructions on exactly how to bring it down. Some antibodies may successfully hit a pathogen's weak spot, while others may miss the mark entirely. That's part of the reason why it normally takes several weeks or months for some vaccines to build up an effective immune response.
Now researchers at the Scripps Research Institute have developed preprogrammed chemicals that bind to antibodies and tell them how to recognize part of a pathogen, known as its epitope. In experiments, the team found that such chemicals prompted a therapeutic immune response that inhibited the growth of two types of tumors in mice. The researchers published their findings in the latest issue of the Proceedings of the National Academies of Science.
"We used a chemistry-based approach that wouldn't induce antibodies that might be wasted," says Carlos Barbas, a professor of molecular biology and lead investigator on the paper. "[This approach] could focus an immune response on functional epitopes of the pathogen, be it cancer or a virus."
The group's chemical-based vaccine may address a number of problems with some current vaccines, both in the clinic and in the lab. Today, there are only two FDA-approved, licensed cancer vaccines: one that targets Hepatitis B associated with liver cancer, the other for human papillomavirus (HPV), which leads to cervical cancer. For both vaccines, patients must go in for multiple immunizations to build up an effective defense over time. There are no licensed therapeutic vaccines that directly treat existing cancers, and researchers have found it difficult to train antibodies to attack cancer cells, since they arise from the body and are not generally regarded by the immune system as foreign.

In the past few years, however, researchers have identified cell-surface markers unique to cancer cells. There are molecules called adjuvants that attach to such markers and trick the immune system into recognizing and attacking tumors. Adjuvants are used in clinics today, but some come with unwanted side effects--for example, soreness, fever, and arthritis. Scientists are now looking for ways to genetically engineer monoclonal antibodies--antibodies created from a single cell line--to recognize tumor markers and attack cancer. But these methods are expensive, and Barbas says that a chemical-based approach may provide a cheaper and faster alternative.

The Endeavors of Endeavour

A photo gallery of the youngest space shuttle as it prepares for its final flight. By Stephen Cass & Brittany Sauser

* Updated Sunday, May 1, 2011, with an image from the launchpad.
The April 29 planned launch of the space shuttle Endeavour, shown here on the launch pad the night before, has been delayed until May 8 at the earliest; engineers detected a malfunction in a unit that provides the hydraulic pressure needed to control the shuttle during takeoffs and landings. The source of the malfunction has been traced to a power control box, the aft load control assembly-2 in Endeavour’s aft compartment. Engineers plan to replace the box and any faulty hardware. With luck, it will be the last glitch in the long story of Endeavour, which has flown 24 times since its maiden voyage in 1992 and will be retired after a final 14-day mission to the International Space Station.

A Vaccine to Attack Cancer Early

Early intervention: In multiple myeloma, cancerous plasma cells, like the ones pictured here, cause disease in the bones, blood, and immune system.

Credit: Nephron, Creative Commons (BY-SA 3.0)

Biomedicine

A Vaccine to Attack Cancer Early

Most cancer vaccines are intended to rally a patient's immune system to fight cancers that have already progressed. But the startup company OncoPep, based in North Andover, Massachusetts, is developing a vaccine designed to prevent one kind of cancer—multiple myeloma—by treating patients with only a precursor of the disease.

Multiple myeloma is a cancer of blood plasma cells. It develops when abnormal plasma cells in bone marrow multiply and accumulate, eventually damaging bones and other tissues in the body and finally overwhelming the immune system. Currently, treatments can extend the lives of patients with cancer but not cure it.

The company's approach grew out of research by Kenneth Anderson, Nikhil Munshi, and Jooen Bae at the Dana-Farber Cancer Institute in Boston. The researchers deployed a combination of peptides—small pieces of protein—that are known to be specific to multiple myeloma cells and are essential for their survival. The goal is to train the immune system to recognise and attack cancer cells bearing these peptides; the vaccine would also contain substances designed to boost immune response.

Plans call for the vaccine to be administered to people diagnosed with smouldering multiple myeloma, a condition in which plasma cells are unusually abundant and produce abnormal proteins but cause no symptoms of the disease. Currently, patients with SMM are not treated. Although a majority of them go on to develop symptomatic cancer, it may take many years. Anderson hopes that the ability to detect the cancer in this early phase will make early, effective intervention possible. "The idea would be to prevent the development of an active cancer," he says. Administering the vaccine to patients before they have received other, possibly debilitating cancer treatments, and while their immune systems are healthy, may give it a better chance of working.

Doris Peterkin, CEO of OncoPep, says that like several other experimental cancer vaccines in development, this one will be matched to people with a particular immune-system type: HLA type A2, the most common type in the U.S. Peterkin says the vaccine is most likely to be effective in these patients because the peptides have a better chance of triggering an immune response in them.

Ronald Levy, an oncologist and cancer researcher at Stanford University, says that despite the advantages of vaccinating early, targeting this early stage of the disease may pose practical problems in testing the vaccine. Although nearly 80 per cent of patients with SMM go on to develop multiple myeloma, they do so at a rate of only about 10 per cent per year—so it may take a while to collect enough patients to test the vaccine. Limiting the vaccine to people with a particular HLA type will narrow the small field. Levy says that the ultimate test of the vaccine's success will be how well its chosen peptides provoke a specific immune response against the cancer, which has been the challenge for all peptide-based cancer.

Energy

Khosla Biofuel IPO Draws Doubters

In 2004, a startup called Nanosys tried to go public. It had recruited some of the world's top nanoscientists for its board and had bought up hundreds of nanotech patents. The idea was that it could revolutionize TV displays, batteries, and maybe even golf balls. It had no product, but so what? Nanotech seemed like it could change everything.
That is when a venture capitalist named Vinod Khosla, then with Kleiner, Perkins, Caufield & Byers, cried fraud. A speech of Khosla's at Stanford University helped to not only torpedo the Nanosys IPO but also burst a short-lived nanotech bubble.
Here's what Khosla said, according to a Thomson Reuters publication, at the time: "Personally, I think it is the wrong model for a company, and I think it is a shame that they are going public, because I do not think they are in a position to be predictable enough. And whether they are doing it knowingly or unknowingly, there is a reasonable likelihood that they will defraud the public market."
Now Khosla's the one being questioned. "I am looking at Vinod Khosla's S-1 filing of KiOR, which has a grand total of zero ($0) revenue," wrote venture capitalist Larry Bock in an e-mail. Bock cofounded Nanosys and was behind the aborted IPO. "Should Vinod be kept accountable?"

For several years, Khosla Ventures has been plowing money into green-energy startups. Now Khosla has begun cashing out by pushing some of his next-generation biofuels companies public. Recent Khosla-backed biofuels IPOs include Amyris and Gevo, and now comes KiOR—a Pasadena, Texas, company that says it will turn wood chips into gasoline and diesel. It expects to raise $100 million in its IPO.
All three companies are early-stage. They're still building plants and proving their ideas. None have turned a profit. KiOR may be the earliest-stage yet. Its SEC filing is long on PowerPoint slogans ("We Drilled Deep Into the Problem ... Not Into Our Planet") but so far KiOR hasn't sold a drop of fuel and cautions investors that "we have no experience producing renewable transportation fuels at the scale needed for the development of our business." The company says it is counting on a $1 billion loan guarantee from the U.S. Department of Energy to build its plants.
Bock now says he wants some "intellectual honesty" from his rival.
So Technology Review asked Khosla whether pre-revenue biofuels companies should be going public. Khosla sent back a detailed memo explaining why biofuels is not like nanotech. Here's a summary:
Existing markets: Biofuels are end applications with large markets, not just technologies.
Proven technology: In many cases the manufacturing or yield of technology has been proven.
Big payoffs: The payback from success is huge. That was not always true in biotech and nanotech, where there is more risk from competitors. In biofuels, the markets are so huge that if 10 companies produced the same product, each could be a billion-dollar business without interfering with the others.
Predictability: If a company can give investors accurate expectations for the next two to three years, then they can consider an IPO. This is true of biofuels now but not of nanotech in 2004.
Khosla's main point is that the fuels market is gigantic, whereas Nanosys was all about technologies looking for problems to solve. He argues that having interesting technology without a compelling market is not a good place to be as a business. Even Nanosys's current chief financial officer, John Page, agrees with that. "That is a fairly accurate assessment of where Nanosys was in 2004." Nanosys recently reorganized in an effort to generate more revenue from LEDs and batteries.