ScienceDaily (Apr. 12, 2010) — Do you carry a cell phone? Today, chances are it’s called a “smartphone” and it came with a three-to-five megapixel lens built-in — not to mention an MP3 player, GPS or even a bar code scanner. This ‘Swiss-Army-knife’ trend represents the natural progression of technology — as chips become smaller/more advanced, cell phones absorb new functions.

What if, in the future, new functions on our cell phones could also protect us from toxic chemicals?

Homeland Security’s Science and Technology Directorate (S&T)’s Cell-All is such an initiative. Cell-All aims to equip cell phones with a sensor capable of detecting deadly chemicals. The technology is ingenious. A chip costing less than a dollar is embedded in a cell phone and programmed to either alert the cell phone carrier to the presence of toxic chemicals in the air, and/or a central station that can monitor how many alerts in an area are being received. One might be a false positive. Hundreds might indicate the need for evacuation.

“Our goal is to create a lightweight, cost-effective, power-efficient solution,” says Stephen Dennis,Cell-All’s program manager.

How would this wizardry work? Just as antivirus software bides its time in the background and springs to life when it spies suspicious activity, so Cell-All would regularly sniffs the surrounding air for certain volatile chemical compounds.

When a threat is sensed, an alert ensues in one of two ways. For personal safety issues such as a chlorine gas leak, a warning is sounded; the user can choose a vibration, noise, text message or phone call. For catastrophes such as a sarin gas attack, details — including time, location and the compound — are phoned home to an emergency operations center. While the first warning is beamed to individuals, the second warning works best with crowds. And that’s where the genius of Cell-All lies — in crowd sourcing human safety.

Currently, if a person suspects that something is amiss, he might dial 9-1-1, though behavioral science tells us that it’s easier to do nothing. And, as is often the case when someone phones in an emergency, the caller may be difficult to understand, diminishing the quality of information that’s relayed to first responders. An even worse scenario: the person may not even be aware of the danger, like the South Carolina woman who last year drove into a colorless and poisonous ammonia cloud.

In contrast, anywhere a chemical threat breaks out — a mall, a bus, subway or office – Cell-All will alert the authorities automatically. Detection, identification, and notification all take place in less than 60 seconds. Because the data are delivered digitally, Cell-All reduces the chance of human error. And by activating alerts from many people at once, Cell-All cleverly avoids the long-standing problem of false positives. The end result: emergency responders can get to the scene sooner and cover a larger area — essentially anywhere people are, casting a wider net than stationary sensors can.

And the privacy issue? Does this always-on surveillance mean that the government can track your precise whereabouts whenever it wants? To the contrary, Cell-All will operate only on an opt-in basis and will transmit data anonymously.

“Privacy is as important as technology,” says Dennis. “After all, for Cell-All to succeed, people must be comfortable enough to turn it on in the first place.”

For years, the idea of a handheld weapons of mass destruction detector has engaged engineers. In 2007, S&T called upon the private sector to develop concepts of operations. Today, thanks to increasingly successful prototype demonstrations, the Directorate is actively funding the next step in R&D — a proof of principle — to see if the concept is workable.

To this end, three teams from Qualcomm, the National Aeronautics and Space Administration (NASA), and Rhevision Technology are perfecting their specific area of expertise. Qualcomm engineers specialize in miniaturization and know how to shepherd a product to market. Scientists from the Center for Nanotechnology at NASA’s Ames Research Center have experience with chemical sensing on low-powered platforms, such as the International Space Station. And technologists from Rhevision have developed an artificial nose — a piece of porous silicon that changes colors in the presence of certain molecules, which can be read spectrographically.

Similarly, S&T is pursuing what’s known as cooperative research and development agreements with four cell phone manufacturers: Qualcomm, LG, Apple and Samsung. These written agreements, which bring together a private company and a government agency for a specific project, often accelerate the commercialization of technology developed for government purposes. As a result, Dennis hopes to have 40 prototypes in about a year, the first of which will sniff out carbon monoxide and fire.

To be sure, Cell-All’s commercialization may take several years. Yet the goal seems eminently achievable: Just as Gates once envisioned a computer on every desk in every home, so Dennis envisions a chemical sensor in every cell phone in every pocket, purse or belt holster.

And if it’s not already the case, says Dennis, “Our smartphones may soon be smarter than we are.”

Sourced and published by Henry Sapiecha 14th April 2010

April 1, 2007 — Polymer chemists have created a flexible, indestructible material, called metal rubber, that can be heated, frozen, washed or doused with jet fuel, and still retain its electricity-conducting properties. To make metal rubber, chemists and engineers use a process called self-assembly. The material is repeatedly dipped into positively charged and negatively charged solutions. The positive and negative charges bond, forming layers that conduct electricity. Uses of metal rubber include bendy, electrically charged aircraft wings, artificial muscles and wearable computers.

Portable gadgets were meant to be taken on the move. Portable also means accidents and damage can happen. Now, imagine electronics that can take a beating and bounce back! It’s soon possible with a shocking new flexible, indestructible material, called metal rubber.

“You can heat it. You can freeze it. You can stretch it. You can douse it with jet fuel,” Jennifer Lalli, a polymer chemist at NanoSonic, Inc., in Blacksburg, Va., tells DBIS.

Abuse it, and metal rubber snaps back to its original shape. But the best part of this rubbery material? It conducts electricity just like metal and is also lightweight.

To make metal rubber, chemists and engineers use a process called self-assembly. The material is repeatedly dipped into positively charged and negatively charged solutions. The positive and negative charges bond, forming layers that conduct electricity.

“Electricity flows through metal rubber because there are little metal particles, and the electricity flows from little metal particle, to little metal particle, to little metal particle, between the two ends just like a piece of copper metal,” Rick Claus, a NanoSonic electrical engineer, tells DBIS.

The self-assembly process coats almost anything — even fabric can be made to carry electrical power. Lalli says you can wash the metal rubber textiles and they maintain electrical current.

Scientists are looking into uses of metal rubber like bendy, electrically charged aircraft wings and artificial muscles — and wearable computers. Abuse-resistant, flexible circuits, like cell phones, are still years away, but the future looks bright — and powerful — for bendable products.

ScienceDaily (Mar. 26, 2010) — Scientists have presented a design strategy to produce the long-sought artificial leaf, which could harness Mother Nature’s ability to produce energy from sunlight and water in the process called photosynthesis. The new recipe, based on the chemistry and biology of natural leaves, could lead to working prototypes of an artificial leaf that capture solar energy and use it efficiently to change water into hydrogen fuel, they stated.

Their report was scheduled for the 239th National Meeting of the American Chemical Society (ACS) in San Francisco. It was among more than 12,000 scientific reports scheduled for presentation at the meeting, one of the largest scientific gatherings of 2010.

“This concept may provide a new vista for the design of artificial photosynthetic systems based on biological paradigms and build a working prototype to exploit sustainable energy resources,” Tongxiang Fan, Ph.D. and colleagues Di Zhang, Ph.D. and Han Zhou, Ph.D., reported, They are with the State Key Lab of Matrix Composites at Shanghai Jiaotong University, Shanghai, China.

Fan pointed out that using sunlight to split water into its components, hydrogen and oxygen, is one of the most promising and sustainable tactics to escape current dependence on coal, oil, and other traditional fuels. When burned, those fuels release carbon dioxide, the main greenhouse gas. Combustion of hydrogen, in contrast, forms just water vapor. That appeal is central to the much-discussed “Hydrogen Economy,” and some auto companies, such as Toyota, have developed hydrogen-fueled cars. Lacking, however, is a cost-effective sustainable way to produce hydrogen.

With that in mind, Fan and co-workers decided to take a closer look at the leaf, nature’s photosynthetic system, with plans to use its structure as a blueprint for their next generation of artificial systems. Not too surprisingly, the structure of green leaves provides them an extremely high light-harvesting efficiency. Within their architecture are structures responsible focusing and guiding of solar energy into the light-harvesting sections of the leaf, and other functions.

The scientists decided to mimic that natural design in the development of a blueprint for artificial leaf-like structures. It led them to report their recipe for the “Artificial Inorganic Leaf” (AIL), based on the natural leaf and titanium dioxide (TiO2) — a chemical already recognized as a photocatalyst for hydrogen production.

The scientists first infiltrated the leaves of Anemone vitifolia — a plant native to China — with titanium dioxide in a two-step process. Using advanced spectroscopic techniques, the scientists were then able to confirm that the structural features in the leaf favorable for light harvesting were replicated in the new TiO2 structure. Excitingly, the AIL are eight times more active for hydrogen production than TiO2 that has not been “biotemplated” in that fashion. AILs also are more than three times as active as commercial photo-catalysts. Next, the scientists embedded nanoparticles of platinum into the leaf surface. Platinum, along with the nitrogen found naturally in the leaf, helps increase the activity of the artificial leaves by an additional factor of ten.

In his ACS presentation, Fan reported on various aspects of Artificial Inorganic Leaf production, their spectroscopic work to better understand the macro- and microstructure of the photocatalysts, and their comparison to previously reported systems. The activity of these new “leaves,” are significantly higher than those prepared with classic routes. Fan attributes these results to the hierarchical structures derived from natural leaves:

“Our results may represent an important first step towards the design of novel artificial solar energy transduction systems based on natural paradigms, particularly based on exploring and mimicking the structural design. Nature still has much to teach us, and human ingenuity can modify the principles of natural systems for enhanced utility.”

Sourced and published by Henry Sapiecha 9th April 2010

ScienceDaily (Sep. 8, 2005) — Scientists at the Technical University of Denmark have invented a technology which may be an important step towards the hydrogen economy: a hydrogen tablet that effectively stores hydrogen in an inexpensive and safe material.

With the new hydrogen tablet, it becomes much simpler to use the environmentally-friendly energy of hydrogen. Hydrogen is a non-polluting fuel, but since it is a light gas it occupies too much volume, and it is flammable. Consequently, effective and safe storage of hydrogen has challenged researchers world-wide for almost three decades. At the Technical University of Denmark, DTU, an interdisciplinary team has developed a hydrogen tablet which enables storage and transport of hydrogen in solid form.

“Should you drive a car 600 km using gaseous hydrogen at normal pressure, it would require a fuel tank with a size of nine cars. With our technology, the same amount of hydrogen can be stored in a normal gasoline tank”, says Professor Claus Hviid Christensen, Department of Chemistry at DTU.

The hydrogen tablet is safe and inexpensive. In this respect it is different from most other hydrogen storage technologies. You can literally carry the material in your pocket without any kind of safety precaution. The reason is that the tablet consists solely of ammonia absorbed efficiently in sea-salt. Ammonia is produced by a combination of hydrogen with nitrogen from the surrounding air, and the DTU-tablet therefore contains large amounts of hydrogen. Within the tablet, hydrogen is stored as long as desired, and when hydrogen is needed, ammonia is released through a catalyst that decomposes it back to free hydrogen. When the tablet is empty, you merely give it a “shot” of ammonia and it is ready for use again.

“The technology is a step towards making the society independent of fossil fuels” says Professor Jens Nørskov, director of the Nanotechnology Center at DTU. He, Claus Hviid Christensen, Tue Johannessen, Ulrich Quaade and Rasmus Zink Sørensen are the five researchers behind the invention. The advantages of using hydrogen are numerous. It is CO2-free, and it can be produced by renewable energy sources, e.g. wind power.

“We have a new solution to one of the major obstacles to the use of hydrogen as a fuel. And we need new energy technologies – oil and gas will not last, and without energy, there is no modern society”, says Jens Nørskov.

Together with DTU and SeeD Capital Denmark, the researchers have founded the company Amminex A/S, which will focus on the further development and commercialization of the technology.

Sourced and published by Henry Sapiecha 9th April 2010

A liquid nitrogen vehicle is powered by liquid nitrogen, which is stored in a tank. The engine works by heating the liquid nitrogen in a heat exchanger, extracting heat from the ambient air and using the resulting pressurized gas to operate a piston or rotary engine.

Liquid nitrogen propulsion may also be incorporated in hybrid systems, e.g., battery electric propulsion and fuel tanks to recharge the batteries. This kind of system is called a hybrid liquid nitrogen-electric propulsion. Additionally, regenerative braking can also be used in conjunction with this system.

A liquid nitrogen economy is a hypothetical proposal for a future economy in which the primary form of energy storage and transport is liquid nitrogen. It is proposed as an alternative to liquid hydrogen in some transport modes and as a means of locally storing energy captured fromrenewable sources. An analysis of this concept provides insight into the physical limits of all energy conversion schemes.

Description

Currently, most road vehicles are powered by internal combustion engines burning fossil fuel. If transportation is to be sustainable over the long term, the fuel must be replaced by something else produced by renewable energy. The replacement should not be thought of as an energy source; it is a means of transferring and concentrating energy, a “currency” or energy carrier.

Liquid nitrogen is generated by cryogenic or Stirling engine coolers that liquefy the main component of air, nitrogen (N₂). The cooler can be powered by renewable-generated electricity or through direct mechanical work from hydro or wind turbines.

Liquid nitrogen is distributed and stored in insulated containers. The insulation reduces heat flow into the stored nitrogen; this is necessary because heat from the surrounding environment boils the liquid, which then transitions to a gaseous state. Reducing inflowing heat reduces the loss of liquid nitrogen in storage. The requirements of storage prevent the use of pipelines as a means of transport. Since long-distance pipelines would be costly due to the insulation requirements, it would be costly to use distant energy sources for production of liquid nitrogen. Petroleum reserves are typically a vast distance from consumption but can be transferred at ambient temperatures.

Liquid nitrogen consumption is in essence production in reverse. The Stirling engine or cryogenic heat engine offers a way to power vehicles and a means to generate electricity. Liquid nitrogen can also serve as a direct coolant for refrigerators, electrical equipment and air conditioning units. The consumption of liquid nitrogen is in effect boiling and returning the nitrogen to the atmosphere.

Criticisms

Cost of production

Liquid nitrogen production is an energy-intensive process. Currently practical refrigeration plants producing a few tons/day of liquid nitrogen operate at about 50% of Carnot efficiency

Energy density of liquid nitrogen

Any process that relies on a phase-change of a substance will have much lower energy densities than processes involving a chemical reaction in a substance, which in turn have lower energy densities than nuclear reactions. Liquid nitrogen as an energy store has a low energy density. Liquid hydrocarbon fuels by comparison have a high energy density. A high energy density makes the logistics of transport and storage more convenient. Convenience is an important factor in consumer acceptance. The convenient storage of petroleum fuels combined with its low cost has led to an unrivaled success. In addition, a petroleum fuel is a primary energy source, not just an energy storage and transport medium.

The energy density — derived from nitrogen’s isobaric heat of vaporization and specific heat in gaseous state — that can be realised from liquid nitrogen at atmospheric pressure and zero degrees Celsius ambient temperature is about 97 watt-hours per kilogram (W-hr/kg). This compares with about 3,000 W-hr/kg for a gasoline combustion engine running at 28% thermal efficiency, 30 times the density of liquid nitrogen used at the Carnot efficiency

For an isothermal expansion engine to have a range comparable to an internal combustion engine, an 350-litre (92 US gal) insulated onboard storage vessel is required . A practical volume, but a noticeable increase over the typical 50-litre (13 US gal) gasoline tank. The addition of more complex power cycles would reduce this requirement and help enable frost free operation. However, no commercially practical instances of liquid nitrogen use for vehicle propulsion exist.

Frost formation

Unlike internal combustion engines, using a cryogenic working fluid requires heat exchangers to warm and cool the working fluid. In a humid environment, frost formation will prevent heat flow and thus represents an engineering challenge. To prevent frost build up, multiple working fluids can be used. This adds topping cycles to ensure the heat exchanger does not fall below freezing. Additional heat exchangers, weight, complexity, efficiency loss, and expense, would be required to enable frost free operation 

Safety

However efficient the insulation on the nitrogen fuel tank, there will inevitably be losses by evaporation to the atmosphere. If a vehicle is stored in a poorly ventilated space, there is some risk that leaking nitrogen depletes the level of oxygen in the air and causes asphyxiation. Since nitrogen is a colorless and odourless gas that already makes up 78 % of air, such a change is difficult to detect.

Cryogenic liquids are hazardous if spilled. Liquid nitrogen can cause frostbite and can make some materials extremely brittle.

Tanks

The tanks must be designed to safety standards appropriate for a pressure vessel, such as ISO 11439.

The storage tank may be made of:

• steel,
• aluminium,
• carbon fiber,
• Kevlar,
• other materials, or combinations of the above.

The fiber materials are considerably lighter than metals but generally more expensive. Metal tanks can withstand a large number of pressure cycles, but must be checked for corrosion periodically.

Emission output

Like other non-combustion energy storage technologies, a liquid nitrogen vehicle displaces the emission source from the vehicle’s tail pipe to the central electrical generating plant. Where emissions-free sources are available, net production of pollutants can be reduced. Emission control measures at a central generating plant may be more effective and less costly than treating the emissions of widely-dispersed vehicles.

Advantages

Liquid nitrogen vehicles are comparable in many ways to electric vehicles, but use liquid nitrogen to store the energy instead of batteries. Their potential advantages over other vehicles include:

• Much like electrical vehicles, liquid nitrogen vehicles would ultimately be powered through the electrical grid. Which makes it easier to focus on reducing pollution from one source, as opposed to the millions of vehicles on the road.
• Transportation of the fuel would not be required due to drawing power off the electrical grid. This presents significant cost benefits. Pollution created during fuel transportation would be eliminated.
• Lower maintenance costs
• Liquid nitrogen tanks can be disposed of or recycled with less pollution than batteries.
• Liquid nitrogen vehicles are unconstrained by the degradation problems associated with current battery systems.
• The tank may be able to be refilled more often and in less time than batteries can be recharged, with re-fueling rates comparable to liquid fuels.

Disadvantages

The principal disadvantage is the inefficient use of primary energy. Energy is used to liquify nitrogen, which in turn provides the energy to run the motor. Any conversion of energy between forms results in loss. For liquid nitrogen cars, energy is lost when electrical energy is converted to liquid nitrogen.

Liquid nitrogen is not yet available in public refueling stations.

January 1, 2009 — Cyber forensic researchers designed a device to extract the memory of a mobile phone for crime scene evidence. The phone’s memory card is placed in the device where computer software extracts and decodes the information–revealing call history, text messages, emails, images, video and the calendar. This information is then used by police as evidence in crimes.

A good fingerprint at a crime scene isn’t always the smoking gun for solving crimes. Thanks to new technology, crime solving is going digital.

Ernest Brice had plans to rent out his house, but it became a target for burglars instead. Thieves stole almost everything inside.

“I feel victimized,” said Brice.

Brice’s crime was never solved, but police say digital evidence left behind from cell phones, computers or PDAs can be found at nearly every crime scene.

“A lot of times, it’s evidence that will take you to your next step in the investigative lead, so it will tell us who this person has been in touch with or who they’ve been emailing or texting,” said Richard Mislan, Ph.D., a cyber-forensic researcher at Purdue University in West Lafayette, Ind.

To help dig up digital evidence and catch criminals, cyber-forensic researchers use a device called a flasher box. It finds clues hiding in cell phones.

“A flasher box is used for extracting a full memory from a mobile phone,” Dr. Mislan said.

A phone’s memory card is removed and plugged into a flasher box. Computer software extracts the phone’s coded information and decodes the information to reveal the phone’s call history, text messages, e-mails, calendar, images and videos. This information is then used by cops as clues to solve crimes.

“It’s an inside look into that person, much more than just a fingerprint,” Dr. Mislan said.

The technology also helps victims of serious crimes by finding clues from computers to show who last contacted the victim and last visited Web sites or e-mails.

“It’s a way of helping us find the perpetrator or the suspect and taking us to that next step,” Dr. Mislan said. Solving crimes isn’t easy. Just ask Brice — but now, technology may help cops get one step ahead of the bad guys. Researchers are now developing a first-responder digital evidence collection kit to gather evidence immediately at the scene of a crime.