Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog – Page 5006

EPFL researchers have shown that people’s perception of office temperature can vary considerably. Personalized climate control could therefore help enhance workers’ comfort—and save energy at the same time.

Global warming means that heatwaves are becoming ever-more frequent. At the same time, we’re in a global race against the clock to reduce buildings’ energy use and carbon footprint by 2050. This has shone the spotlight on the importance of making the thermal comfort of buildings a strategic and economic priority. And this is the focus of research conducted by Dolaana Khovalyg, a tenure track assistant professor at EPFL’s School of Architecture, Civil and Environmental Engineering (ENAC) and head of the Laboratory of Integrated Comfort Engineering (ICE), which is linked to the Smart Living Lab in Fribourg.

In her latest study, published as a brief, cutting-edge report in the journal Obesity, she highlights the benefits of providing personalized thermal conditioning and heating for each office desk, rather than maintaining a standard temperature throughout an open space. Khovalyg and her team came to this conclusion after the human thermo-physiological data they collected showed that individuals display very different levels of thermal comfort under normal office conditions.

Read more | >

It’s a basic rule of chemistry and physics: when you heat things up, they get bigger. While there are exceptions (like water and ice), it’s difficult to find a material with zero thermal expansion.

But new research from the University of New South Wales and the Australian Nuclear Science and Technology Organisation has found a compound that doesn’t thermally expand – at least, not between −269°C and 1126°C.

The researchers examined a substance made from scandium, aluminium, tungsten and oxygen (Sc1.5 Al0.5 W3 O12), bonded together in a crystalline structure.

Read more | >

Metamaterial Space Applications:

In this presentation I will talk about nanophotonics, more specifically metasurfaces – subwavelength patterned surfaces – and explain how this can be used for space applications. As recently displayed by the stunning images from the James Webb space telescope, we often rely on recording the intensity of light (e.g. with a camera) to study the universe. However, light fundamentally has several additional degrees of freedom which can carry information, e.g. polarization, phase, and spectral content. While it is true that many conventional optical components can address these degrees of freedom individually (e.g., polarizers, phase retarders, and filters), metasurfaces enable general manipulations of phase, amplitude, and polarization on the nanoscale, thereby providing ample opportunity to create new versions of existing components and even enable functionality not possible using conventional technologies. In the presentation I will cover several examples of metasurfaces I have been working on and explain their relevance for space applications. I will attempt to explain the working principles, why metasurfaces can be useful, as well as how we fabricate metasurfaces in a cleanroom.

About the speaker: Dr. Tobias Wenger is a postdoc at JPL’s microdevices laboratory (MDL) where his main efforts relate to nanophotonics — light at the nanoscale – and how we can engineer structures and components in order to control light in new ways. Tobias received his PhD from Chalmers University of Technology, Sweden, where he worked on understanding the physical properties of plasmons in graphene.

At JPL, Tobias is applying his knowledge of subwavelength electromagnetics to design metasurface-based optical components, mainly for infrared wavelengths. Metasurfaces are a novel approach to optics which uses subwavelength elements for controlling the phase, amplitude and polarization of transmitted and/or reflected electromagnetic radiation. Tobias research interests intersect optics, computational electromagnetics, and microfabrication and he enjoys both the practical and theoretical aspects of this work. During his postdoc time at MDL, he has worked on metasurface-based optical concentrators, IR detectors, plasmonic filters, wavefront sensing, and grating replication.

Read more | >

Researchers at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have found that updating a mathematical model to include a physical property known as resistivity could lead to the improved design of doughnut-shaped fusion facilities known as tokamaks.

“Resistivity is the property of any substance that inhibits the flow of electricity,” said PPPL physicist Nathaniel Ferraro, one of the collaborating researchers. “It’s kind of like the viscosity of a fluid, which inhibits things moving through it. For example, a stone will move more slowly through molasses than water, and more slowly through water than through air.”

Scientists have discovered a new way that can cause instabilities in the edge, where temperatures and pressures rise sharply. By incorporating resistivity into models that predict the behavior of plasma, a soup of electrons and that makes up 99% of the visible universe, scientists can design systems for future that make the plasma more stable.

Read more | >

Scientists have been grappling with the strangeness of quantum entanglement for decades, and it’s almost as mysterious in 2022 as it was when Einstein famously dubbed the phenomenon “spooky action at a distance” in 1947. An experiment in Germany that set a new entanglement distance record — with atoms rather than photons — could help shed some light on this quirk of the universe.

Entanglement was initially proposed in the early 20th century as a consequence of quantum mechanics, but many scientists of the day, even Einstein himself, considered it to be impossible. However, many of the counterintuitive predictions of quantum mechanics have been verified over the years, including entanglement. As we’ve seen in numerous experiments, it is possible for particles to be “entangled” such that properties like position, momentum, spin, and polarization can be shared between them. A change in one is immediately reflected in its twin.

Scientists believe entanglement could form the basis for future communication systems that are faster and more secure than what we use today — if you measure the state of one entangled partner, you automatically know the state of the other, and this could be used to transmit data. You just need to separate the entangled pair to make it useful, and researchers from Ludwig-Maximilians-University Munich (LMU) and Saarland University have pushed that range much farther in the new experiment.

Read more | >

Physics World

To get around this problem, Kanté and colleagues utilized photonic crystals. These are periodic structures, which, like electronic semiconductors, have “band gaps” – frequencies at which they are opaque. Like graphene in electronics, photonic crystals generally contain Dirac cones in their band structures. At the vertex of such a cone is the Dirac point, where the band gap closes.

Read more | >