In order to allow rain to produce electricity as well, the research team coated a solar cell with a whisper-thin film of graphene. Credit: Copyright Angewandte Chemie International Edition; courtesy of ResearchSEA
Many advances have made solar cells quite efficient and affordable but a disadvantage is that solar cells produce no power when it’s raining. This may change, however. Chinese researchers have now introduced a new approach for making an all-weather solar cell that is triggered by both sunlight and raindrops. They developed a highly efficient dye-sensitized solar cell. In order to allow rain to produce electricity as well, they coated this cell with a whisper-thin film of graphene.
Graphene can readily be prepared by the oxidation, exfoliation, and subsequent reduction of graphite...
Shear jamming image. Credit: Image courtesy of University of Southampton
Liquid-like materials with particles in, known as dense suspensions, are found in the food industry (eg molten chocolate) and clay deposits on the bottom of oceans or rivers. Understanding the ‘jamming transition’ – when such a system behaves like a solid (if you want to build something on it) or when it flows (important if you want to process it) – could help in the design of new materials that actively use this transition from fluid-like to solid-like behaviour.
Ivo Peters, Lecturer in Aerodynamics and Flight Mechanics Research Group at the Uni of Southampton...
Chunks of this sodium-based compound (Na2B12H12) (left) would function well in a battery only at elevated temperatures, but when they are milled into far smaller pieces (right), they can potentially perform even in extreme cold, making them even more promising as the basis for safer, cheaper rechargeables. Credit: Tohoku University, Japan
By chemically modifying and pulverizing a promising group of compounds, scientists at the National Institute of Standards and Technology (NIST) have potentially brought safer, solid-state rechargeable batteries 2 steps closer to reality. These compounds are stable solid materials that would not pose the risks of leaking or catching fire typical of traditional liquid battery ingredients and are made from commonly available substances.
Schematic representation of the four stages of CaSO4 formation.
A new explanation of how gypsum forms may change the way we process this important building material, as well as allow us to interpret past water availability on other planets such as Mars. Gypsum (CaSO. 4· 2H2O) is an economically important mineral, extensively used as the commercial construction material Plaster of Paris, with a global production of ~100 billion kg per year. It is a ubiquitous mineral on the Earth’s surface, and is also found on the surface of Mars. Despite its importance, until now we have not understood how gypsum grows from ions in solutions.
The formation of gypsum, from concentrated aqueous solutions of calcium sulfate, was thought to be a simple, single-step process. However, a group of European geochemists has now shown that gypsum forms through a complex 4-step process: the understanding of this process opens the way to more energy efficient production of plaster.
The multinational team examined the process using in situ and time resolved synchrotron-based X-ray scattering at Diamond Light Source (Harwell, UK), and identified and quantified each of the 4 steps of the formation process, highlighting specially that the initial moments in the reaction chain are of particular importance, because they determine the final properties of gypsum. In this 1st step, tiny sub-3 nm elongated particles form the primary building blocks (bricks). In subsequent steps these bricks aggregate, self-assemble and rearrange themselves, and finally transform to gypsum crystals.
“Importantly, we envisage that it is possible to alter this pathway by specifically targeting individual stages. For example we could arrest the reaction at the first stage when only nano-bricks are formed, and thus directly synthesise a highly reactive precursor to Plaster of Paris” said Dr. Thomas Stawsky. Since plaster is normally produced by the energy-intensive heating of gypsum, such an approach would drastically reduce the cost of production, and significantly decrease the carbon footprint of the industry.
“We know that gypsum is naturally found on Mars, so applying our current finding will also help us understand and predict the hydrological conditions at the time of gypsum formation on other planets,” said Professor Liane G. Benning. http://www.eurekalert.org/pub_releases/2016-04/eaog-sdh032916.php
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