No losses: Scientists stuff graphene with light

EurekAlert  November 16, 2020 Researchers in Russia developed a technique to achieve 90% energy conversion from the pump laser field to the surface plasmon polaritons (SPPs) on the base of the hybrid optoplasmonic multi‐level scheme of near‐resonant interaction with semiconductor quantum dots (QDs) placed in the proximity of a graphene surface. Using numerical simulations and semiclassical approach for the light–matter interaction they found that maximum efficiency of SPP generation is achieved in strong coupling conditions for a stationary regime of SPP‐QD interaction. The technique can be used for converting energy in solar cells, and nano and bio-object detection…read more. TECHNICAL […]

Building walls that will make summer heat waves more bearable

Phys.org  September 28, 2020 A team of researchers in South Korea propose Phase Change Material (PCM) wall device using bubble injection method for the application of PCM in building envelopes. The density difference between PCM and bubbles causes the upward movement of the bubbles and flow in the liquid PCM destroying temperature stratification in the PCM and heat penetration across the PCM is reduced. With the application of the bubble injection method, 11% more latent heat energy was stored in the PCM, 28% less heat penetrated across the PCM wall and the average flow rate inside the liquid PCM with […]

Faster, more efficient energy storage could stem from holistic study of layered materials

Science Daily  August 25, 2020 An international team of researchers (USA – Oak Ridge National Laboratory, Georgia State University, Tulane University, Drexel University, Portugal) integrated theoretical data from computational modeling of experimental data to pinpoint potential locations of a variety of charged ions in titanium carbide, the most studied MXene phase. MXenes are a class of two-dimensional materials constructed in layers that are only a few atoms thick. They were able to form links between theory and different types of materials characterization, ranging from very simple to very complex over a wide range of length and time scales. The study’s […]

Efficient Off-Grid Power, After the Sun Sets

Optics and Photonics  August 19, 2020 An international team of researchers (USA – Stanford, Israel) analyzed the basic thermodynamics of a heat engine, with the hot side under the roof and the top of the roof radiating thermal energy out into the environment. They developed models to maximize the amount of electrical power generated for various temperature gradients. The team’s design for a nighttime power generator would occupy a rooftop area of 1 m2. It incorporates a radiative emitting panel, a state-of-the-art TEG made of metal alloy, and a heat sink, with radiation shields and insulative pegs to reduce radiative […]

Engineers develop new fuel cells with twice the operating voltage as hydrogen

EurekAlert  June 17, 2020 Researchers at Washington University have developed high-power direct borohydride fuel cells that operate at double the voltage of conventional hydrogen fuel cells. They pioneered a reactant identifying an optimal range of flow rates, flow field architectures and residence times that enable high power operation ensuring proper fuel and oxidant distribution and the mitigation of parasitic reactions. They demonstrated a single-cell operating voltage of 1.4 or greater, double that obtained in conventional hydrogen fuel cells, with peak powers approaching 1 watt/cm2. Doubling the voltage would allow for a smaller, lighter, more efficient fuel cell design. Their approach […]

Using the ‘shadow effect’ to generate electricity

Techxplore  May 21, 2020 Researchers in Singapore used Kelvin Probe Force Microscopy to experimentally validated that a shadow-effect energy generator (SEG) scavenges the illumination contrast that arises on the device from shadow castings, and generates a direct current, simply by placing a part of the generator in shadow. The SEG is capable of harvesting energy from illumination contrasts arising under weak ambient light. Without any optimization, the generator has a power density of 0.14 μW cm−2 under indoor conditions 0.001 sun, where shadows are persistent. It performs 200% better than that of commercial silicon solar cells under the effects of […]

Fossil fuel-free jet propulsion with air plasmas

Science Daily  May 5, 2020 Researchers in China propose a prototype design of a propulsion thruster that utilizes air plasma induced by microwave ionization. They used a microwave air plasma jet thruster using high-temperature and high-pressure plasma generated by a 2.45 GHz microwave ionization chamber for injected pressurized air. They measured the lifting force and jet pressure at various settings of microwave power and the air flow rate and demonstrated that, given the same power consumption, its propulsion pressure is comparable to that of conventional airplane jet engines using fossil fuels. A carbon-emission free thruster could potentially be used as […]

Pentagon awards contracts to design mobile nuclear reactor

Defense News  March 9, 2020 Project Pele is run through the Strategic Capabilities Office within DDR&E of DOD, involves the development of a safe, mobile and advanced nuclear microreactor to support a variety of Department of Defense missions such as generating power for remote operating bases. Under the program the Pentagon issued three contracts to start design work as part of a two-step plan. The system should be safely and rapidly moveable by road, rail, sea, or air and quick to set up and shut down, with a design which is inherently safe. If the testing goes well, a commercially […]

How to Design a Perpetual Energy Machine

Quanta Magazine  April 1, 2020 It is a tradition among puzzle columnists to pay homage to April Fools’ Day by testing the credulity of their readers with outrageous propositions. The late (and great) Martin Gardner, who authored the famous monthly column Mathematical Games in Scientific American for a quarter century, once used an April column to describe a thought experiment that purported to falsify the special theory of relativity. It was a version of the bar and ring paradox. Special relativity is still hale and hearty, but the thought experiment seems convincing at first glance. In the spirit of this […]

Turning water into watts

Physics World  March 3, 2020 Most approaches to harvesting mechanical energy from ocean waves rely on finding a way to move a conducting wire through a magnetic field to generate electricity. Researchers at Georgia Institute of Technology designed triboelectric nanogenerators (TENGs) in small plastic spheres, about the size of oranges, that float in water. As the waves jostle the sphere, material inside bumps against the outer shell, generating charges. Th charges then flow through an attached wire. In lab tests each sphere could generate about 10 mW of power enough for powering small devices such as sensors on buoys used […]