University of Missouri-Columbia (MU) researchers have created a long-lasting and more efficient nuclear battery. Its built from a radioactive isotope called strontium 90 that boosts electrochemcial energy in a water-based solution with a nanostructured titanium dioxide electrode with a platinum coating collecting and effectively converting energy into electrons.
The idea has many high power applications such as a reliable energy source in automobiles and also in complicated applications such as space flight. Its a superlative idea that is now working.
Jae W. Kwon, an associate professor of electrical and computer engineering and nuclear engineering in the College of Engineering at MU said, “Betavoltaics, a battery technology that generates power from radiation, has been studied as an energy source since the 1950s. Controlled nuclear technologies are not inherently dangerous. We already have many commercial uses of nuclear technologies in our lives including fire detectors in bedrooms and emergency exit signs in buildings.”
The nuclear name part is going to be the problem. After all, strontium 90 is a long way from uranium 235 or plutonium 244 (atomic numbers respectively, 38, 92 & 94). Strontium 90 is a beta emitter, the radiation energy that powers the battery. Still, beta emitters are not something a home shop operator should be working with, as light shielding is required. Sealed within few millimeters of aluminum would do.
Kwon explains the system, “Water acts as a buffer and surface plasmons created in the device turned out to be very useful in increasing its efficiency. The ionic solution is not easily frozen at very low temperatures and could work in a wide variety of applications including car batteries and, if packaged properly, perhaps spacecraft.”
The MU battery demonstrates that liquids can be an excellent media for effective energy conversion from radioisotopes. The water based ionic fluid is also contributes to the shielding. The battery is also a direct conversion method producing electric power straight from energetic particles rather than an indirect conversion methods such as collecting electricity from the secondary energy forms of heat or light.
How the battery works is the beta particles produce electron-hole pairs in semiconductors via their loss of kinetic energy and can contribute to the generation of electric power.
So far the solid beta decay battery design problem has been serious radiation damage to the lattice structures of semiconductors and subsequent performance degradation due to the high kinetic energy of the beta particles pounding the solid construction to pieces.
The MU battery stands out with the major benefit of utilizing a liquid-phase material and the liquid’s well-known ability to efficiently absorb the kinetic energy of beta particles. The fluid absorbs the energy and passes much of it to the semiconductor.
This is where the innovation or breakthrough comes in. Since the advent of nuclear power, liquids have been intensively studied for use as a radiation-shielding material. Large amounts of radiation energy can be absorbed by water. When radiation energy is absorbed by an aqueous solution, free radicals can be produced through radiolytic interactions. The MU battery demonstrates a new method for the generation of electricity using a device that separates the radiolytic current from the free radicals by splitting the water.
The water splitter is composed of a nanoporous semiconductor coated with a thin platinum film to produce a specially designed metal-semiconductor junction. For the semiconductor they used a very stable and common large band gap oxide material, titanium dioxide (white paint pigment), because of the large band gap oxide materials offer as a semiconducting catalyst that can improve the radiolysis yield.
What happens is during the spitting high-energy beta radiation the device can produce free radicals in water through the loss of kinetic energy. In a meta-stable state, the free radicals are recombined into water molecules or trapped in water molecules. Then the free radicals produced by the radiation can be converted into electricity by a plasmon-assisted, wide band gap oxide semiconducting material.
How good is this first lab theory test battery? Hold on to something . . .
The maximum energy conversion efficiency of the MU battery was approximately estimated to be 53.88%. This is an astonishing number for a first trial design.
That’s enough for a news type of posting. For more information the paper can be read in full online at this writing. Some of you are going to realize that strontium 90 has a half life of 28.79 years. The implications of that thought are mind boggling.
September 17, 2014 | 2 Comments
An Ohio State University led study has pinpointed the likely source of most natural gas contamination in drinking-water wells associated with hydraulic fracturing is the walls of the gas well and their well casing seal to the ground.
It’s not the source many people may have feared and should, if the press can get its facts – truth – and integrity act together, the news should enable the natural gas industry, the state regulators and well engineers an opportunity to solve the public’s anti fracking issue with real results for much improved water well protection.
The problem should be fixable with improved construction standards for cement well linings and metal well casings at hydraulic fracturing sites.
The team was led by a researcher at The Ohio State University and composed of researchers at Duke, Stanford, Dartmouth, and the University of Rochester. The team devised a new method of geochemical forensics to trace how methane migrates under the earth. The study identified eight clusters of contaminated drinking-water wells in Pennsylvania and Texas.
Most important among their findings, published this week in the Proceedings of the National Academy of Sciences, is that neither horizontal drilling nor hydraulic fracturing of shale deposits seems to have caused any of the natural gas contamination. This will not come as much of a surprise to those in the industry and mechanical engineers.
Study leader Thomas Darrah, assistant professor of earth sciences at Ohio State said, “There is no question that in many instances elevated levels of natural gas are naturally occurring, but in a subset of cases, there is also clear evidence that there were human causes for the contamination. However our data suggests that where contamination occurs, it was caused by poor casing and cementing in the wells.”
Robert Poreda, professor of geochemistry at the University of Rochester explained, “Many of the leaks probably occur when natural gas travels up the outside of the borehole, potentially even thousands of feet, and is released directly into drinking-water aquifers.”
Avner Vengosh, professor of geochemistry and water quality at Duke said, “These results appear to rule out the migration of methane up into drinking water aquifers from depth because of horizontal drilling or hydraulic fracturing, as some people feared.”
Robert B. Jackson, professor of environmental and earth sciences at Stanford and Duke pointed out, “In some cases homeowner’s water has been harmed by drilling. In Texas, we even saw two homes go from clean to contaminated after our sampling began.”
“This is relatively good news because it means that most of the issues we have identified can potentially be avoided by future improvements in well integrity,” Darrah said.
In hydraulic fracturing, water is pumped underground to break up shale at a depth far below the water table, he explained. The long vertical pipes that carry the resulting gas upward are encircled in cement to keep the natural gas from leaking out along the well. The study suggests the natural gas that has leaked into aquifers is the result of failures in the cement used in building the well.
The method that the researchers used to track the source of methane contamination relies on the basic physics of the noble gases (which happen to leak out along with the methane). Noble gases such as helium and neon are so called because they don’t react much with other chemicals, although they mix with natural gas and can be transported with it.
That means that when they are released underground, they can flow long distances without getting waylaid by microbial activity or chemical reactions along the way. The only important variable is the atomic mass, which determines how the ratios of noble gases change as they tag along with migrating natural gas. These properties allow the researchers to determine the source of fugitive methane and the mechanism by which it was transported into drinking water aquifers.
The researchers were able to distinguish between the signatures of naturally occurring methane and stray gas contamination from shale gas drill sites overlying the Marcellus shale in Pennsylvania and the Barnett shale in Texas.
The researchers sampled water from the sites in 2012 and 2013. Sampling sites included wells where contamination had been debated previously; wells known to have naturally high level of methane and salts, which tend to co-occur in areas overlying shale gas deposits; and wells located both within and beyond a one-kilometer distance from drill sites.
As hydraulic fracturing starts to develop around the globe, including the countries of South Africa, Argentina, China, Poland, Scotland, and Ireland, Darrah and his colleagues are continuing their work in the United States and internationally. And, since the method that the researchers employed relies on the basic physics of the noble gases, it can be employed anywhere. Their hope is that their findings can help highlight the necessity to improve well integrity.
The team’s hope isn’t misplaced. While the anti fracking crowd can go home now, they probably won’t. There will be new players on the field soon, the trial lawyers will be after the well drilling contractors to pony up for the wells where natural gas is spoiling the water wells.
The story isn’t over, but the hydraulic fracking is not the problem, allowing most well location landowners, most of the natural gas industry, and all of us consumers a great sigh of relief. The problems will get worked out.
Adding Biomethane (methane from biomass) to the natural gas supply is held up by lack of standardized and international content conditions. An effort to generate further growth has come from the Helmholtz Center for Environmental Research (UFZ), the German Biomass Research Center (DBFZ), other Members of the IEA Task 37 (Energy from Biogas) and the Task 40 (Sustainable Bioenergy Trade).
Biomethane would work as a substitute for the fossil derived natural gas offering a variety of options and applications for a sustainable energy supply. While the general abundance of natural gas in the U.S. keeps North America freed from worry, the situation in Europe and much of Asia is fraught with risk as “Putinism” rises from the old Soviet Union. The situation across Western Europe and some former soviet states is quite serious.
Nevertheless, in most of the IEA member states natural gas still plays an important and increasing role in the national energy supply. This is because of a well-developed infrastructure of gas networks, natural gas fueling stations, and various modes of portable transportation. Due to the significantly lower greenhouse gas emissions, the protection of finite resources, and especially now energy security several countries initiated support programs for biomethane (methane from biomass). Now several countries have initiated the gradual transition from fossil natural gas resource on to renewable energy sources of biomethane.
The researchers noted above have published their study “Biomethane – Status and Factors Affecting Market Development and Trade,” giving an up-to-date and comprehensive overview of the production technologies of biomethane (upgrading of biogas and Bio-SNG), the grid injection and the use in various IEA member states.
Te report is a quite well written and organized piece available in a downloadable pdf file. For those in the biomethane, natural gas industry, or an interested investor or customer it is a highly enlightening work.
In addition to the description of the framework, the options and needs for the development of larger biomethane supply strategies are also illustrated. The authors finalize the study with concrete recommendations how the remaining barriers can be removed and the market development can be promoted step by step.
Biomethane offers considerable benefits including independence from natural gas imports, the strengthening of farm and forestry economies and its promising application areas as a motor fuel, used for cogeneration, and home and industrial heating.
For the final composition of biomethane it must be consistent with the various natural gas quality levels in the market before it can serve as a substitute for natural gas. Preprocessing is somewhat different, the contaminants include different mixes of CO2, nitrogen, sulfur, and water vapor.
The market is pretty well advanced. Some 277 pilot sized plants are already in operation in primarily in Europe and in North America. So far though, even the international natural gas market is mostly regional, putting biomethane at something of a disadvantage.
An international biomethane market is, according to the study, still in its infancy. However, various strategies, investment programs, funding and utilization concepts have been adopted in the investigated countries. Because of the complex supply chain there are various ecological, economic, administrative and political barriers for a market implementation of biomethane.
For a sustainable and international implementation appropriate technical standards, sustainability requirements and political as well as financial support (compensation / promotion / preference), in order to significantly advance the development of an international biomethane trade, are necessary.
The study will provide interested persons a useful tool to assist others in understanding what is needed to firm up, for the immediate future, the European gas market. This study as well as the very recent announcement of a Liquid Natural Gas Market opening should light quite a fire of effort to add to Eurasian supplies. It may not be in time to save the Ukrainians from Putinism and its ravages, but it looks to ravage the Putinism command economy in the coming years as gas supplies for Europe increase and diversify.
September 11, 2014 | 2 Comments
A team of researchers at the University of Texas at Arlington has discovered a way to cool electrons to -228 °C without external means and at room temperature. This can be an impressive advancement that may enable electronic devices to function with very little energy.
In the image above is a chip that contains nanoscale structures that enable electron cooling at room temperature. The process involves passing electrons through a quantum well to cool them and keep them from heating.
The Texas team explained its research in “Energy-Filtered Cold Electron Transport at Room Temperature” published in Nature Communications. Co-authors of the paper are Pradeep Bhadrachalam, Ramkumar Subramanian, Vishva Ray and Liang-Chieh Ma from UT Arlington, and Weichao Wang, Prof. Jiyoung Kim and Prof. Kyeongjae Cho from UT Dallas.
Research team leader Seong Jin Koh, an associate professor at UT Arlington in the Materials Science & Engineering Department said, “We are the first to effectively cool electrons at room temperature. Researchers have done electron cooling before, but only when the entire device is immersed into an extremely cold cooling bath. Obtaining cold electrons at room temperature has enormous technical benefits. For example, the requirement of using liquid helium or liquid nitrogen for cooling electrons in various electron systems can be lifted.”
Koh explained electrons are thermally excited even at room temperature, which is a natural phenomenon. If that electron excitation could be suppressed, then the temperature of those electrons could be effectively lowered without external cooling.
The team used a nanoscale structure – which consists of a sequential array of a source electrode, a quantum well, a tunneling barrier, a quantum dot, another tunneling barrier, and a drain electrode – to suppress electron excitation and to make electrons cold.
Cold electrons promise a new type of transistor that can operate at extremely low-energy consumption.
“Implementing our findings to fabricating energy-efficient transistors is currently under way,” Koh added.
Khosrow Behbehani, dean of the University of Texas Arlington College of Engineering, said this research is representative of the University’s role in fostering innovations that benefit the society, such as creating energy-efficient green technologies for current and future generations.
“Dr. Koh and his research team are developing real-world solutions to a critical global challenge of utilizing the energy efficiently and developing energy-efficient electronic technology that will benefit us all every day,” Behbehani said. “We applaud Dr. Koh for the results of this research and look forward to future innovations he will lead.”
Usha Varshney, program director in the National Science Foundation’s Directorate for Engineering, which funded the research, said the research findings could be vast. “When implemented in transistors, these research findings could potentially reduce energy consumption of electronic devices by more than 10 times compared to the present technology. Personal electronic devices such as smart phones, iPads, etc., can last much longer before recharging,” he said.
In addition to potential commercial applications, there are many military uses for the technology. Batteries weigh a lot, and less power consumption means reducing the battery weight of electronic equipment that soldiers are carrying, which will enhance their combat capability. Other potential military applications include electronics for remote sensors, unmanned aerial vehicles and high-capacity computing in remote operations.
Future research could include identifying key elements that will allow electrons to be cooled even further. The most important challenge of this future research is to keep the electron from gaining energy as it travels across device components. This would require research into how energy-gaining pathways could be effectively blocked.
This new technology has only just begun. The possible application are astounding, add LEDs as a large market and as a practical matter for now most any IC chip may benefit from cooler operation. One other point not yet mentioned is the effect the new tech could have on superconductivity efforts.
Its a major breakthrough, indeed.
University of Manchester scientists think tiny single-cell organisms discovered living underground could help with the problem of nuclear waste disposal. Bacteria with waste-eating properties have been discovered in relatively pristine soils before. The Manchester study is the first time that microbes have been found that can survive in the very harsh conditions expected in radioactive waste disposal sites.
Nuclear fission power is stalled in a major way by the waste issues. The study work isn’t dealing directly with used fuel rods, instead it focuses on the immense volumes of lower level waste.
The disposal of nuclear waste is very challenging, with very large volumes destined for burial deep underground. The largest volume of radioactive waste, termed ‘intermediate level’ and comprising of 364,000 cubic meters, is a volume large enough to fill four of the famous London Albert Halls.
Such waste will be encased in concrete prior to disposal into underground vaults. When ground waters eventually reach these waste materials, one problem is they will react with the cement and become highly alkaline. This change drives a series of chemical reactions, triggering the breakdown of the various ‘cellulose’ based materials that are present in these complex wastes.
One such product linked to these activities, isosaccharinic acid (ISA), causes much concern as it can react with a wide range of radionuclides – unstable and toxic elements that are formed during the production of nuclear power and make up the radioactive component of nuclear waste. If the ISA binds to radionuclides, such as uranium, then the radionuclides will become far more soluble and more likely to flow out of the underground vaults to surface environments, where they could enter drinking water or the food chain.
However, the researchers’ new findings indicate that microorganisms may prevent this from becoming a problem.
Working on soil samples from a highly alkaline industrial site in England’s Peak District, which is not radioactive but does suffer from severe contamination with highly alkaline lime kiln wastes, the team discovered specialist “extremophile” bacteria that thrive under the alkaline conditions expected in cement-based radioactive waste. The organisms are not only superbly adapted to live in the highly alkaline lime wastes, but they can use the ISA as a source of food and energy under conditions that mimic those expected in and around intermediate level radioactive waste disposal sites. For example, when there is no oxygen (a likely scenario in underground disposal vaults) to help these bacteria “breath” and break down the ISA, these simple single-cell microorganisms are able to switch their metabolism to breath using other chemicals in the water, such as nitrate or iron.
The fascinating biological processes that they use to support life under such extreme conditions are being studied by the Manchester group, as well as the stabilizing effects of these humble bacteria on radioactive waste. The ultimate aim of this work is to improve our understanding of the safe disposal of radioactive waste underground by studying the unusual diet of these hazardous waste eating microbes.
One of the researchers, Professor Jonathan Lloyd, from the University’s School of Earth, Atmospheric and Environmental Sciences, said, “We are very interested in these Peak District microorganisms. Given that they must have evolved to thrive at the highly alkaline lime-kiln site in only a few decades, it is highly likely that similar bacteria will behave in the same way and adapt to living off ISA in and around buried cement-based nuclear waste quite quickly.”
“Nuclear waste will remain buried deep underground for many thousands of years so there is plenty of time for the bacteria to become adapted. Our next step will be to see what impact they have on radioactive materials. We expect them to help keep radioactive materials fixed underground through their unusual dietary habits, and their ability to naturally degrade ISA,” Lloyd said.
While this technology isn’t dealing with used fuel rods there are technologies that can make the rods safer and extract the energy remaining within. That said, fuel rod volume is far lower than the waste the Manchester team is working on.
The Manchester team may well have an important first step in reducing and concentrating intermediate waste. Steadily working at the problem may someday come to extracting the radioactive elements for recycling back into useful products.