Phys.org November 23, 2020 Numerous missions planned for the next decade are likely to target a handful of small sites of interest on the Moon’s surface, creating risks of crowding and interference at these locations. Regions richest in physical resources could also be uniquely suited to settlement and commerce. Such sites of interest are both few and small. An international team of researchers (USA – Harvard University, Missouri University of Science and Technology, UK) surveyed the implications for different kinds of mission and find that the diverse actors pursuing incompatible ends at these sites could soon crowd and interfere with […]
Improving quantum dot interactions, one layer at a time
Science Daily November 20, 2020 Controlling interaction between quantum dots could greatly improve charge transport, leading to more efficient solar cells. Researchers fabricated CdTe quantum dot superlattices via the layer-by-layer assembly of positively charged polyelectrolytes and negatively charged CdTe quantum dots to control the dimension of the quantum resonance by independently changing the distances between quantum dots in the stacking (out-of-plane) and in-plane directions. They experimentally verified the miniband formation. The fabrication method can be used with other types of water-soluble quantum dots and nanoparticles. Combining different types of semiconductor quantum dots, or combining semiconductor quantum dots with other nanoparticles, […]
Research creates hydrogen-producing living droplets, paving way for alternative future energy source
Phys.org November 25, 2020 Normally, algal cells fix carbon dioxide and produce oxygen by photosynthesis. An international team of researchers used sugary droplets packed with living algal cells to generate hydrogen, rather than oxygen, by photosynthesis. They trapped ten thousand or so algal cells in each droplet, which were then crammed together by osmotic compression. By burying the cells deep inside the droplets, oxygen levels fell to a level that switched on special enzymes called hydrogenases that hijacked the normal photosynthetic pathway to produce hydrogen. In this way, around a quarter of a million microbial factories, typically only one-tenth of […]
Researchers decipher structure of promising battery materials
MIT News November 23, 2020 MOFs’ extraordinary combination of porosity and conductivity opened the possibility of new applications in batteries, fuel cells, supercapacitors, electrocatalysts, and specialized chemical sensors. Because of the chemical bonds within the MOFs it has been difficult to grow crystals that were large enough for study to figure out their exact molecular structure and how it influences the material’s properties. An international team of researchers (USA – MIT, University of Oregon, University of Connecticut, Purdue University, China, Sweden) has found a way to control the growth of crystals of several kinds of MOFs enabling the team to […]
Researchers invent broad-band tunable terahertz absorber
Phys.org November 24, 2020 THz absorbers with strong absorption, broad-band absorption bandwidth and tunable characteristics have attracted the attention of many researchers with extensive application prospects in THz wave shielding, THz imaging, and THz sensitive thermal detecting. Researchers in China introduced strongly correlated electron material VO2 as a functional layer and realized the broad-band tunable THz spectrum properties in the device. The conductivity, dielectric constant, as well as optical properties got a dramatic switching during the insulator-metal transition at TC = 340 K, and the transition could be tuned by temperature, electric field, and light. The device had a 74% […]
Researchers model urban airflows to help improve the design of drones, skyscrapers, and natural ventilation systems
Phys.org November 25, 2020 Scientists presented the latest findings on modeling and predicting urban airflow at the 73rd Annual Meeting of the American Physical Society’s Division of Fluid Dynamics in the hope of building better buildings, cities, and transportation. According to the scientists in addition to the challenges of traffic congestion and obstacles, critical technology gaps exist in modeling, detecting, and accommodating the dynamic urban local wind fields as well as in precision navigation through uncertain weather conditions. They attached sensors to robotic aircraft to take more cohesive measurements of building wakes, or the disturbed airflow around buildings. They combined […]
Scientists Detect ‘Superbolts’ 1,000 Times Brighter Than Typical Lightning Strikes
Science Alert November 24, 2020 Researchers at the Los Alamos National Laboratory used Fast On-Orbit Detection of Transient Events (FORTE) satellite observations to identify superbolt-class optical lightning events and evaluate their origins. Superbolts have been defined as lightning pulses whose peak optical power exceeds 1011 W. However, it has been unclear whether superbolts resulted from particular types of high-energy lightning process or whether they were the result of measurement bias. According to their 12-year analysis of FORTE superbolt detections indicates that the lower optical superbolt energy range (~100 GW) is dominated by normal lightning, but brighter cases are predominantly strong […]
Self-diagnostic carbon nanocomposites
Nanowerk November 23, 2020 Studies have shown that carbon nanomaterials can increase required mechanical properties with relatively small addition amounts, all the while allowing the final material to be electrically conductive and piezoresistive in nature but their incorporation into large scale production requires intensive facility upgrades. Researchers in Russia used masterbatches and industrially available, inexpensive manufacturing techniques to examine how the addition of carbon nanoparticles can change the electric conductivity of polymer matrices. Essentially, the use of such materials has the potential to replace sensors in weight critical systems such as aircraft structures, with the material itself being able to […]
Shift in atmospheric rivers could affect Antarctic sea ice, glaciers
Science Daily November 23, 2020 Researchers at UCLA investigated the atmospheric river (AR) frequency trends over the Southern Hemisphere using three reanalyses and two Community Earth System Model (CESM) ensembles. Their results show that AR frequency has been increasing over the Southern Ocean and decreasing over lower latitudes in the past four decades and that ARs have been shifting poleward. While the observed trends are mostly driven by the poleward shift of the westerly jet, the experiments indicate anthropogenic forcing would result in positive AR frequency trends over the Southern Ocean due mostly to moisture changes. They conclude that the […]
Topological mechanical metamaterials go beyond Newton’s third law
Phys.org November 19, 2020 An international team of researchers (Israel, Los Alamos) found a way to mimic non-Newtonian behavior in mechanical systems, and thereby develop a mechanical implementation for some of the more intractable topological quantum systems, which may offer fundamentally new insights into both the mechanical and quantum topological systems. The unit cells in a mechanical lattice are subjected to active feedback forces that are processed through autonomous controllers, pre-programmed to generate the desired local response in real-time. They demonstrated that the required topological phase, characterized by chiral edge modes, can be achieved in an analogous mechanical system only […]