Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: energy – Page 107

A better way to wirelessly charge over long distances has been developed at Aalto University. Engineers have optimized the way antennas transmitting and receiving power interact with each other, making use of the phenomenon of “radiation suppression”. The result is a better theoretical understanding of wireless power transfer compared to the conventional inductive approach, a significant advancement in the field.

Charging over short distances, such as through induction pads, uses magnetic near fields to transfer power with high efficiency, but at longer distances the efficiency dramatically drops. New research shows that this high efficiency can be sustained over long distances by suppressing the radiation resistance of the loop antennas that are sending and receiving power. Previously, the same lab created an omnidirectional wireless charging system that allowed devices to be charged at any orientation. Now, they have extended that work with a new dynamic theory of wireless charging that looks more closely at both near (non-radiative) and far (radiative) distances and conditions. In particular, they show that high transfer efficiency, over 80 percent, can be achieved at distances approximately five times the size of the antenna, utilizing the optimal frequency within the hundred-megahertz range.

‘We wanted to balance effectively transferring power with the radiation loss that always happens over longer distances,’ says lead author Nam Ha-Van, a postdoctoral researcher at Aalto University. ‘It turns out that when the currents in the loop antennas have equal amplitudes and opposite phases, we can cancel the radiation loss, thus boosting efficiency.’

Read more | >

Measurements conducted over an unprecedented span of conditions uncover universal behavior, but not the kind that theorists expected.

Turbulence is a mesmerizing, chaotic state of fluid motion. It occurs in natural and artificial settings whenever the Reynolds number (quantifying the relative size of inertial to viscous forces in the flow) is large. Through nonlinear coupling, kinetic energy cascades from large scales to ever smaller scales (Fig. 1) until it is dissipated by viscous effects. The fluctuations excited during this process play a crucial role in a diverse range of problems, including planetesimal formation [1], rain initiation in clouds [2], and heat transport within oceans [3]. Remarkably, a new experimental study by Christian Küchler of the Max Planck Institute for Dynamics and Self-Organization in Germany and co-workers provides compelling evidence that current theoretical models for how the fluctuations are distributed across the scales are missing some important ingredients [4].

Turbulent flows are complex. Quantitative predictions of their properties that are derived directly from the Navier-Stokes equation, without ad hoc assumptions, are accordingly scarce. Most theoretical approaches have perforce been phenomenological, the most famous being Andrey Kolmogorov’s groundbreaking 1941 theory, nicknamed K41 [5]. This mean-field theory assumes that the multiscale properties of the turbulent fluctuations are governed by the average cascade of kinetic energy passing through the scales and by the fluid viscosity. In K41 Kolmogorov went on to propose the existence of an inertial range, which corresponds to an intermediate range of scales over which viscous forces could be ignored relative to inertial forces and where the details of the large-scale forcing are unimportant.

Read more | >

A team of researchers led by Associate Professor Kazuhiro Nakazawa from Nagoya University.

Nagoya University, sometimes abbreviated as NU, is a Japanese national research university located in Chikusa-ku, Nagoya. It was the seventh Imperial University in Japan, one of the first five Designated National University and selected as a Top Type university of Top Global University Project by the Japanese government. It is one of the highest ranked higher education institutions in Japan.

Read more | >

New standard for green hydrogen technology set by Rice U. engineers.

Rice University engineers can turn sunlight into hydrogen with record-breaking efficiency thanks to a device that combines next-generation halide perovskite semiconductors with electrocatalysts in a single, durable, cost-effective and scalable device.

The new technology is a significant step forward for clean energy and could serve as a platform for a wide range of chemical reactions that use solar-harvested electricity to convert feedstocks into fuels.

Read more | >

The interaction of light and matter on the nanoscale is a vital aspect of nanophotonics. Resonant nanosystems allow scientists to control and enhance electromagnetic energy at volumes smaller than the wavelength of the incident light. As well as allowing sunlight to be captured much more effectively, they also facilitate improved optical wave-guiding and emissions control. The strong coupling of light with electronic excitation in solid-state materials generates hybridized photonic and electronic states, so-called polaritons, which can exhibit interesting properties such as Bose-Einstein condensation and superfluidity.

Read more | >

Rice University engineers can turn sunlight into hydrogen with record-breaking efficiency thanks to a device that combines next-generation halide perovskite semiconductors with electrocatalysts in a single, durable, cost-effective and scalable device.

The new technology is a significant step forward for and could serve as a platform for a wide range of chemical reactions that use solar-harvested electricity to convert feedstocks into fuels.

The lab of chemical and biomolecular engineer Aditya Mohite built the integrated photoreactor using an anticorrosion barrier that insulates the from water without impeding the transfer of electrons. According to a study published in Nature Communications, the device achieved a 20.8% solar-to-hydrogen conversion efficiency.

Read more | >

Built using inexpensive semiconductors, the device packs all components to make hydrogen and can be scaled.

A research team led by Aditya Mohite, a professor of chemical and biomolecular engineering at Rice University in the US, has designed a device that can use sunlight to generate hydrogen, with a record efficiency of 20.8 percent, a press release said.

Hydrogen is being touted as the future of clean energy due to its high energy density that could be deployed even to fly large planes. However, the process of generating hydrogen is currently heavily dependent on fossil fuels. For hydrogen to herald a new future in clean energy, it needs to be produced sustainably and without carbon emissions.

Read more | >

Researchers have developed an advanced dielectric capacitor using nanosheet technology, providing unprecedented energy storage density and stability. This breakthrough could significantly enhance renewable energy usage and electric vehicle production.

A research group, led by Nagoya University.

Nagoya University, sometimes abbreviated as NU, is a Japanese national research university located in Chikusa-ku, Nagoya. It was the seventh Imperial University in Japan, one of the first five Designated National University and selected as a Top Type university of Top Global University Project by the Japanese government. It is one of the highest ranked higher education institutions in Japan.

Read more | >

Astronomers at the University of Sydney have shown that a small, faint star is the coldest on record to produce emission at radio wavelength.

The ‘ultracool brown dwarf’ examined in the study is a ball of gas simmering at about 425 degrees centigrade—cooler than a typical campfire—without burning .

By contrast, the surface temperature of the sun, a nuclear inferno, is about 5,600 degrees.

Read more | >