Science & Technology News Bulletin

Every week, we editorially select the best S&T stories released from major news outlets. These stories are then ranked and posted (with appropriate credit and references to the originals) on our Blog by Friday afternoon. Hema Viswanath curates this content and has been doing so for ASDR&E's Office of Net Technical Assessments and Office of Technical Intelligence for over seven years before performing the same work for us. Currently, we are experimenting with distributing this content through a free, advertising-supported model. We intend to continue experimenting using paywalls, direct e-mail subscriptions and donations. Hosting this content is important to us and we would like to retain it on at least a revenue-neutral basis. We are also experimenting with enriching the content to make it more relevant to our Government clients.

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Scientists synthesize an analog of the Earth’s most complex mineral in a laboratory

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Top 10 Science and Technology Inventions for the Week of November 25, 2022

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Scientists synthesize an analog of the Earth’s most complex mineral in a laboratory

Discovery reveals ‘brain-like computing’ at molecular level is possible

Phys.org  November 21, 2022
An international team of researchers (Singapore, USA – University of Central Florida, the Netherlands, Germany, Australia, Ireland) has created a new type of organic material that learns from its past behavior emulating synaptic behavior. The molecule switches from high to low conductance states with massive negative memristive behaviour that depends on the drive speed and number of past switching events. The dynamic molecular switch provides all the fundamental logic gates necessary for deep learning because of its time-domain and voltage-dependent plasticity. The switch represents an adaptable molecular-scale hardware operable in solid-state devices and opens a pathway to simplify dynamic complex electrical operations encoded within a single ultracompact component…read more. TECHNICAL ARTICLE 

Electrical characteristics of the Au-S-C10-HATNA//Ga2O3/EGaIn junctions. Credit: Nature Materials (2022) 

Electrokinetic mining technology for recovering rare earth elements from weathering crusts

Phys.org  November 17, 2022
Ion-adsorption deposits, which form within weathering crusts, supply more than 95% of the scarce global heavy rare earth elements (HREE) demand. Deposits are currently mined via ammonium-salt-based leaching techniques that are responsible for severe environmental damage and show low recovery efficiency. Researchers in China have designed an innovative rare earth elements (REE) mining technique, electrokinetic mining (EKM), which enabled green, efficient and selective recovery of REEs from weathering crusts. Its feasibility was demonstrated via bench-scale, scaled-up and on-site field experiments. Compared with conventional techniques, EKM achieved ~2.6 times higher recovery efficiency, an ~80% decrease in leaching agent usage and a ~70% reduction in metallic impurities in the obtained REEs. According to the researchers the evidence presented suggested that EKM is a viable mining technique…read more. TECHNICAL ARTICLE 

…IAD mining via EKM and AIP mechanisms. Credit: Nature Sustainability (2022) 

Engineers solve a mystery on the path to smaller, lighter batteries

MIT News  November 18, 2022
Whether dendrites are driven by mechanical failure or electrochemical degradation of solid electrolytes remains an open question. If internal mechanical forces drive failure, superimposing a compressive load that counters internal stress may mitigate dendrite penetration. A team of researchers in the US (MIT, Brown University) investigated this hypothesis by dynamically applying mechanical loads to growing dendrites in Li6.6La3Zr1.6Ta0.4O12 solid electrolytes. Operando microscopy revealed marked deflection in the dendrite growth trajectory at the onset of compressive loading. Sufficient loading the deflection averted cell failure. They quantified the impact of stack pressure and in-plane stresses on dendrite trajectory, charted the residual stresses required to prevent short-circuit failure, and proposed design approaches to achieve such stresses. For the materials they studied the dendrite propagation was dictated by electrolyte fracture, with electronic leakage playing a negligible role…read more. TECHNICAL ARTICLE 

…applying a compression force across a solid electrolyte material (gray disk) caused the dendrite (dark line at left) to stop moving… Credit: MIT

Glass-like shells of diatoms help turn light into energy in dim conditions

Nanowerk  November 22, 2022
Using a toolkit consisting of numerical models and four microscopy techniques, researchers in Canada evaluated the optical response of frustules belonging to the species Nitzschia filiformis. Localized regions of the frustule exhibited functionalities including diffraction, lensing, waveguiding, circulation, filtering, resonances, and dispersion control. They showed that these functionalities are complementary to each other in contributing to the solar energy harvesting mechanisms of capture, redistribution, and retention. In this context, frustule performance was enhanced by perturbations to its sub-wavelength structure. According to the researchers their finding provides quantitative support to the hypothesis that the frustule enhances photosynthesis in the cell and supports the case for cultivating diatoms as sustainably mass-manufacturable devices with applications in solar energy, carbon sequestration, sensing, medicine, and metamaterials…read more. Open Access TECHNICAL ARTICLE 

Architecture of the frustule… Credit: Optical Materials Express Vol. 12, Issue 12, pp. 4665-4681 (2022) 

Leading the way in superconductor research: New compounds of lanthanum and hydrogen

Phys.org  November 22, 2022
An international team of researchers (Germany, UK, Sweden, USA – University of Chicago) has presented the results of their single-crystal X-ray diffraction studies on lanthanum hydrides which revealed an unexpected chemical and structural diversity of lanthanum hydrides synthesized in the range of 50 to 180 GPa. They produced seven lanthanum hydrides LaH3, LaH~4, LaH4+δ, La4H23, LaH6+δ, LaH9+δ, and LaH10+δ, and determined the atomic coordinates of lanthanum in their structures. The regularities in rare-earth element hydrides the team has shown provide clues to guide the search for other synthesizable hydrides and candidate high-temperature superconductors. The hydrogen content variability in lanthanum hydrides and the samples’ phase heterogeneity underline the challenges related to assessing potentially superconducting phases and the nature of electronic transitions in high-pressure hydrides…. read more. Open Access TECHNICAL ARTICLE

Arrangement of lanthanum atoms in the lanthanum hydrides… Credit: Nature Communications volume 13, Article number: 6987 (2022) 

Microlaser chip adds new dimensions to quantum communication

Phys.org  November 21, 2022
In quantum communications with qubits, the superposition makes it so a quantum pulse cannot be copied. However, with only two levels of superposition, qubits have limited storage space and low tolerance for interference. An international team of researchers (USA – University of Pennsylvania, Duke University, City University of New York, Spain, Italy) has created a chip that outstrips the security and robustness of existing quantum communications hardware. The device’s four-level qudits enable significant advances in quantum cryptography, raising the maximum secrete key rate for information exchange from 1 bit per pulse to 2 bits per pulse. The device offers four levels of superposition and opens the door to further increases in dimension… read more. TECHNICAL ARTICLE 

Generation and reconfiguration of SU(4) states. Credit: Nature (2022) 

Monitoring ‘frothy’ magma gases could help evade disaster

Phys.org  November 21, 2022
Researchers in Japan repeatedly measured isotopic compositions of noble gases and CO2 in volcanic gases sampled at six fumaroles around the Kusatsu-Shirane volcano (Japan) between 2014 and 2021 to detect variations reflecting recent volcanic activity. The synchronous increases in 3He/4He at some fumaroles suggested an increase in magmatic gas supply since 2018. The increase in magmatic gas supply was also supported by the temporal variations in 3He/CO2 ratios and carbon isotopic ratios of CO2. The 3He/40Ar* ratios showed significant increases in the period of high 3He/4He ratios. The temporal variation in 3He/40Ar* ratios may reflect changes in magma vesicularity. Therefore, the 3He/40Ar* ratio of fumarolic gases was a useful parameter to monitor the current state of degassing magma, which was essential for understanding the deep process of volcanic unrest and may have contributed to identifying precursors of a future eruption. According to the researchers their results provide additional validation for the use of noble gas and carbon isotopic compositions of fumarolic gases for monitoring magmatic–hydrothermal systems…read more. Open Access TECHNICAL ARTICLE 

Ar three-isotope diagrams for the fumarolic gas samples… Credit: Scientific Reports volume 12, Article number: 17967 (2022) 

New insights into energy loss open doors for one up-and-coming solar tech

Science Daily  November 18, 2022
Understanding the factors affecting energy loss in organic photovoltaics (OPVs) is imperative to achieve further improvements in their efficiency and to establish design rules for the development of new materials. By studying several planar and bulk heterojunction solar cells, an international team of researchers (USA – Princeton University, Saudi Arabia) has demonstrated that the non-radiative energy loss component quadratically increases with increasing Gaussian CT-state disorder. They showed that by defining the total energy loss in terms of the peak of the CT-state distribution the effect of disorder on OPV performance can be unambiguously identified, offering a universal metric for quantifying energy loss across various devices…read more. TECHNICAL ARTICLE

Graphical abstract. Credit: Joule, November 18, 2022 

An on-chip time-lens generates ultrafast pulses

Science Daily  November 11, 2022
Integrated femtosecond pulse and frequency comb sources are critical components for a wide range of applications, including microwave photonics, communications, lidar, optical computing, and astronomy among other things. A team of researchers in the US (Harvard University, UCLA, Columbia University, industry) has demonstrated a chip-scale femtosecond pulse source implemented on an integrated lithium niobate photonic platform forming a time-lens system. The device was driven by a continuous-wave distributed feedback laser chip and controlled by a single continuous-wave microwave source without the need for any stabilization or locking. They measured femtosecond pulse trains with a 30-gigahertz repetition rate, flat-top optical spectra with a 10-decibel optical bandwidth of 12.6 nanometres, individual comb-line powers above 0.1 milliwatts, and pulse energies of 0.54 picojoules. The results represented a tunable, robust, and low-cost integrated pulsed light source with continuous-wave-to-pulse conversion efficiencies an order of magnitude higher than those achieved with previous integrated sources. The pulse generator may find applications in fields such as ultrafast optical measurement or networks of distributed quantum computers….read more. TECHNICAL ARTICLE 

Wavelength multiplexed, flat-top, high power electro-optic comb sources. Credit: Nature (2022)