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Evaluation of the results of the latest research and development activities in the field of alternative energy sources in terms of their innovative capacity (continuation fourth articles)

2012-12-30
Andrew (Gabriel) Livshits

The recent sharp silicon deficiency was the cause of a series of studies and the search for alternatives in the area of potential natural and synthetic substitutes for silicon
For innovation by far the most interesting is to find or create technical solutions that do without silicon
A brief analytical assessment of the published results of such research and development activities
Japanese company Spheral Power showed samples of tissue with integrated power generation spherical solar cells. The announcement of this results in the publication The Asahi Shimbun.
The fabric is based on a previously developed by the spherical solar cells. They are reminiscent of beads beads with a diameter of about 1.2 millimeters. Each of the beads on a sunny day produces about 0.2 mW power. In contrast to the flat panel efficiency of spherical solar cells is almost independent of the angle at which the light falls on them.
Electricity beads woven into the fabric and are connected by a microscopic wires to each other and the battery compartment. Energy of several hundred of these beads, as seen in the photo is sufficient to power the LED, but the exact characteristics of his invention, engineers do not result.
The company had previously demonstrated other products developed on the basis of spherical fotoelemenov, for example, flexible translucent panels intended for use on windows and table lamps.
Recently, another group of engineers introduced a new type of solar cells, which can also be used to create electricity tissues. They represent a silicon optical fibers having to cut three semiconductor area.

Physicists at the University of Pennsylvania have created a thin silicon optical fibers that can capture light and produce electricity from it. The work of scientists published in the journal Advanced Materials, and its summary is provided in a university news release.
Initially team of writers to work on the problem of the connection of optical fibers with flat silicon chips. However, the survey found that, based on silicon can create fibers with integrated electronics.
On cross-section shows that the fiber is actually made up of three classic semiconductor zones. When exposed to light, such fibers generate electricity, although the effectiveness of this process is not specified in the message.
With their thin (with a diameter of about 10 microns), the fibers may not damaged easily bend. The authors hope that these fibers can be woven into a yarn to create electricity tissues. At this point the length of the fibers produced is about a meter, but, according to the researchers, may be increased to 10 meters.
The vast majority of existing solar panels are crystalline or amorphous silicon. The latter allows for a device with a certain level of flexibility. The conversion efficiency of light to electricity of the best solar cells is currently about 40 percent. Also, are now actively being developed panels, where carbon nanotubes and graphene partially or completely replace silicon and metal electrodes.
As in all other areas, now often search kontsentriruetsya on nanotubes
Physicists have made it clear, as do photoelectric properties of the pigments when putting them in double-layer nanotubes. Such a structure has been borrowed by scientists in bacteria and could be the basis for a new type of solar cell. The paper was published in the journal Nature Chemistry, and its summary can be read at the Massachusetts Institute of Technology.
Two-layer structure of the nanotubes, scientists assembled artificial pigments in green sulfur bacteria. These microorganisms are usually found in deep water, where there is little sunlight. Bacterio-chlorophyll they organized in structured complex and very efficiently absorbs radiation.
Scientists have managed to arrange artificial pigments in the nanotubes, making them amphiphilic - that is adding to the molecule hydrophobic and hydrophilic substituents. In aqueous solution, the substances according to the structure form micelles, membranes, or in this case, the double-layer nanotubes.
Connection between the individual molecules of a substance in nanotubes have been so strong that it changes the properties of the light-absorbing pigment. Radiation absorption efficiency also depends on the orientation of the molecules in the structures. At the same time, the interaction between the inner and outer layers of the two-layer nanotubes was minimal.
The results, according to the authors, are essential to create a theoretical model of the behavior of pigments in structured complexes. Prototyping solar cells on nanotubes require a deep understanding of the impact of their structure on efficiency.
Earlier, another group of physicists from the Massachusetts Institute of Technology proposed using to collect solar energy nanotubes formed from a single layer of carbon. The effectiveness of these solar cells is still low, but they can be used to power the infrared part of the spectrum of sunlight, which is inaccessible to conventional PV modules. It is assumed that they can be combined outside of the solar panels.
Comprehensive development of the bio-medical technologies require integration of technology typical of bio-medical facilities with biochemical phenomena discovered in recent
Engineers at the Massachusetts Institute of Technology have created a photovoltaic power generation, which oxidizes glucose from the cerebrospinal fluid. The work of scientists published in the journal PLoS ONE, and its summary retells ScienceNow.
Square chip area of one square millimeter or two provided the cathode, anode and the membrane separating them. A platinum anode glucose is oxidized to form hydrogen ions and electrons. The membrane separating the cathode and anode is permeable only to hydrogen ions but not for electrons. Ions rush through the membrane to the cathode and combine it with oxygen to form water. Electrons are also rushing to the cathode, but not through the membrane, and a microchip circuitry and thus feed its energy.
The anode of the microchip was made of platinum and used for the production of carbon nanotube cathode. Created by the authors tested the device in a solution composed of simulated cerebrospinal fluid. The microchip was able to produce a few hundred microwatts of electrical energy, and the glucose consumption remained relatively small. According to calculations of the researchers, it will be from 3 to 28 percent of the volume is constantly regenerated in the brain glucose. The oxygen consumption of the device is also significantly influenced by its concentration in the cerebrospinal fluid.
According to the authors, by the batteries can be useful for electric power supply machine - brain interface in patients with blindness or profound brain damage. At present all the experimental devices of this kind are powered by wireless induction electricity or batteries that need to be replaced periodically during surgical procedures. Microchips, producing energy from glucose, in the future be able to make such devices completely autonomous.

Scientists have determined how damaged neurons attract microglial cells to help regenerate nerve tissue. The paper was published in the journal Developmental Cell, its summary results ScienceNow.
Biologists are working on a model object - zebrafish brain-rerio (zebrafish, Danio rerio), the genome of which were made of fluorescent protein genes. The neurons of such animals synthesized fluorescent protein red and accessory cells of nervous tissue (called microglia) - green. Since the brain for juvenile zebrafish Danio-transparent, then the behavior of the cells can be observed directly through a microscope.
If the damage of one of the neurons of the laser, the nearby microglial cells rushed to him, surrounded and absorbed the remnants of dead cells. Removal of dead neurons - an important step in the regeneration of nerve tissue.
Scientists have found that the involvement of microglial cells is always accompanied by the spread of the calcium wave - increase in the content of Ca2 + in the neighboring neurons. It normally applies a rate of about 1 millimeter per minute. If you block Ca2 + entry into the nerve cells, the calcium wave and there is no longer involved in the microglia dead neurons. Trigger that triggers a calcium wave that was the neurotransmitter glutamate, which came out of the damaged neurons in the extracellular space - his blocking also inhibited the migration of microglia.
Published work is important for understanding normal development, regeneration and propagation of signals in the brain. In addition, processes of migration of microglia may play a role in the occurrence of neurodegenerative diseases. However, to define this role, scientists will have to switch to the human brain, because fish do not suffer from Alzheimer's and Parkinson's.

American engineers have created a transparent and flexible ionistor that can be a source of food for the next generation of mobile devices. The paper was published in the journal Scientific Reports, and its summary can be read at Northwestern University.
At the heart of the new device - thin carbon films with unusual shapes. They have a deeply textured surface in the form of so-called "carbon nano-chashek." Thanks to such texture increases the contact surface between the film, which acts as an electrode, and "filler" - polymer electrolyte.
To demonstrate the efficiency of technology to create a new class of power sources, the authors have created a small prototype. In the reducible video engineers use it to power the LED, place the device on top of the screen smartphone. We see that very well ionistor transmits light, although not entirely clear. Furthermore, the authors demonstrate that the battery can be sginat and it does not change its electrical performance.
Ionistor (or super-capacitors) are electrical devices in a sense intermediate between the classical chemical capacitors and batteries. As the plates of a ionistor act ions at the boundary layers eletkroda and electrolyte. Than the area of the border, the greater the capacity of the device. The benefits include high ionistor charging rate and a low degradation even after thousands of cycles.
The new development engineers can be useful to create a fully transparent electronic devices. Technology of many other components of these devices, such as touch panels and screens already exist.

... to be continued ...

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