MIT News September 26, 2022 Existing methods for underwater imaging are unsuitable for scalable, long-term, in situ observations because they require tethering for power and communication. Researchers at MIT have developed an underwater backscatter imaging, a method for scalable, real-time wireless imaging of underwater environments using fully submerged battery-free cameras that power up from harvested acoustic energy, capture color images using ultra-low-power active illumination and a monochrome image sensor and communicate wirelessly at net-zero-power via acoustic backscatter. They demonstrated wireless battery-free imaging of animals, plants, pollutants, and localization tags in enclosed and open-water environments. The method’s self-sustaining nature makes it […]
New nanocomposite films boost heat dissipation in thin electronics
Phys.org September 26, 2022 Thermally conductive films with large in-plane anisotropy to prevent thermal interference between heat sources in close proximity and to cool in other directions by diffusion are important for efficient heat dissipation of thin electronic devices. Researchers in Japan have developed flexible composite films composed of a uniaxially aligned carbon-fiber filler within a cellulose nanofiber matrix through liquid-phase three-dimensional patterning. The film exhibited a high in-plane thermal conductivity anisotropy of 433%, with combined properties of a thermal conductivity of 7.8 W/mK in the aligned direction and a thermal conductivity of 1.8 W/mK in the in-plane orthogonal direction. […]
New study shows transmission of epigenetic memory across multiple generations
Phys.org September 26, 2022 Researchers at UC Santa Cruz have shown how a common type of epigenetic modification can be transmitted via sperm not only from parents to offspring, but to the next generation (“grand offspring”) as well. This “transgenerational epigenetic inheritance,” may explain how a person’s health and development could be influenced by the experiences of his or her parents and grandparents. They focused on epigenetic mark (called H3K27me3) in C. elegans. This mark is known to turn off or “repress” the affected genes. They selectively stripped the histone mark from the chromosomes of C. elegans sperm, which were […]
An ocean inside the Earth? Water is determined to be hundreds of kilometers down
Phys.org September 27, 2022 An international team of researchers (USA – Gemological Institute of America, Purdue University, University of Wisconsin, Italy, Germany) analyzed a rare diamond, from Botswana, formed 660 meters below the Earth’s surface confirming that ocean water accompanies subducting slabs and thus enters the transition zone (TZ). This means that our planet’s water cycle includes the Earth’s interior. The immense pressure in the TZ causes the olive-green mineral olivine, which constitutes about 70% of the Earth’s upper mantle. The mineral transformations greatly hinder the movements of rock in the mantle. Subducting plates often have difficulty in breaking through […]
Optical encryption method based on single pixel imaging and metasurface holography
Nanowerk September 26, 2022 The precise control of phase, amplitude, polarization, metasurface holography provides a flexible platform for light modulation, optical encryption. The process of image reconstruction by single pixel imaging is similar to a form of encoding and decoding, which is realized by calculating the correlation between a series of modulation patterns and their corresponding intensity signals. Researchers in China proposed an optical encryption scheme based on spatial multiplexing metasurface, which depends on the combination of holographic technology and single pixel imaging technology. In the encryption scheme, the image transmitted by single pixel imaging based on metasurface was used […]
‘Optical magic’: New flat glass enables optimal visual quality for augmented reality goggles
Phys.org September 28, 2022 Augmented reality (AR) glass needs to be highly transparent over almost the entire visible spectrum. In traditional AR there is a tradeoff in terms of quality and brightness between the external scene and the contextual information you want to visualize. A team of researchers in the US (Columbia University, City University of New York) has demonstrated nonlocal dielectric metasurfaces in the near-infrared that offer both spatial and spectral control of light, realizing metalenses focusing light exclusively over a narrowband resonance while leaving off-resonant frequencies unaffected. This is made possible by quasi-bound state in the continuum encoded […]
Quantum technology reaches unprecedented control over captured light
Phys.org September 27, 2022 An international team of researchers (Sweden, Japan) has developed a technique to overcome to noise and interference in quantum systems. Their technique could create any of the previously demonstrated states and the cubic phase state. They used a sequence of interleaved selective number-dependent arbitrary phase (SNAP) gates and displacements. The state preparation was optimized in two steps – first they used a gradient-descent algorithm to optimize the parameters of the SNAP and displacement gates; then optimized the envelope of the pulses implementing the SNAP gates. The results showed that this way of creating highly nonclassical states […]
Researchers create synthetic rocks to better understand how increasingly sought-after rare earth elements form
Phys.org September 30, 2022 Researchers in Ireland studied the interaction between rare earth element (REE)-rich (La, Pr, Nd, Dy) aqueous solutions, dolomite (CaMg(CO3)2), and aragonite (CaCO3) at low temperature hydrothermal conditions (25–220 °C) to understand the formation of REEs. They found that the newly formed REE-bearing carbonates in La-, Pr-, and Nd-doped systems follow the crystallization sequence: lanthanite [REE2(CO3)3·8H2O] → kozoite [orthorhombic REECO3(OH)] → hydroxylbastnasite [hexagonal REECO3(OH)]. The interaction of Dy-bearing solutions with dolomite results only in the crystallization of kozoite [orthorhombic DyCO3(OH)]. However, experiments with aragonite reveal a two-step crystallization pathway: tengerite [Dy2(CO3)3·2-3(H2O)] → kozoite [orthorhombic DyCO3(OH)]. The temperature, […]
Scientists use modified silk proteins to create new nonstick surfaces
Science Daily September 23, 2022 Silk fibroin protein, a biomaterial, has excellent biocompatibility and low immunogenicity. It is used in stents, catheters, and wound dressings. To further expand its scope and utility a team of researchers in the US (Tufts University, California State University at Fresno) has modulated the hydrophobicity of silk fibroin protein. They found that installing perfluorocarbon chains on the surface of silk fibroin transforms this water-soluble protein into a hydrophobic polymer that can be solvent-cast. A clear relationship emerged between fluorine content of the modified silk and film hydrophobicity. Water contact angles of the most decorated silk […]
Solar geoengineering might work, but local temperatures could keep rising for years
Phys.org September 28, 2022 Stratospheric aerosol injection (SAI), the theoretical deployment of particles in the stratosphere to enhance reflection of incoming solar radiation, is one of the strategies to slow, pause, or reverse global warming. SAI is likely be for a specific aim, such as affording time to implement mitigation strategies, lessening extremes, or reducing the odds of reaching a biogeophysical tipping point. A team of researchers in the US (Colorado State University, US Naval War College, RI) used an ensemble climate model experiment that simulated the deployment of SAI in the context of an intermediate greenhouse gas trajectory quantifying […]