arXiv subjects

Yogesh Kumar Yadav

Publications and source records attributed to Yogesh Kumar Yadav.

3 recordsLinked to original sources

arXiv2026

The Atacama Large Aperture Submillimeter Telescope (AtLAST): enabling large-scale sub-mm science beyond 2030

AtLAST is designed to be the largest (sub-)mm single-dish astronomical observatory and the first climate-neutral modern research infrastructure. It offers a unique combination of large aperture (50 m), large field of view (>1 deg), fast scanning speed (up to 3 deg/s), and high surface accuracy (20micron nighttime half wavefront error) that allows >=50% Ruze efficiency up to 1 THz. The design features a rocking chair mount with an active main reflector surface, a high precision closed-loop metrology system, and the space to house six major instruments. Instruments will be periodically updated as spectroscopic focal plane array, detector, coherent amplifier, and semiconductor technologies used in readout and backend electronics will advance over the next decades. AtLAST will be a multi-purpose facility that will produce transformational results in nearly all fields of Astrophysics, such as Astrochemistry, Galactic and Extragalactic Astronomy, Cosmology, Planetary science, Stellar and Solar Physics, High energy astrophysics, and Time domain astronomy. Its unrivalled throughput of 6170 m^2 deg^2 will enable wide-field unbiased surveys. These will overcome extragalactic confusion noise and enable the detection of normal galaxy populations out to z=7. AtLAST will reveal and characterise the missing baryons in the Universe, by mapping the elusive, low surface brightness gas within and around galaxies across cosmic time. AtLAST will be the first green off-grid observatory, powered by a bespoke renewable energy system and reusing its braking energy thanks to a cutting-edge energy recovery system. By sharing surplus power and technological know-how with local communities, AtLAST will contribute to energy justice in Chile. AtLAST's new bold vision of a sustainable pursuit of breakthrough astronomy is an exceptional opportunity to shape the future of scientific research infrastructures. [abridged]

astro-ph.IM↗

arXiv2025

Hydrogen storage in nanocrystalline high entropy material

In this study, a single-phase nanocrystalline Al-Cu-Fe-Ni-Cr high-entropy alloy (HEA) has been synthesized by mechanical alloying and comprehensively investigated for hydrogen storage responses evaluated in details. High-energy attritor ball mill was used to synthesize the alloy from elemental powder, and hexane medium was used as a process control agent. As synthesized materials was nanocrystalline in nature after 40 h of milling with a lattice parameter of 0.289 nm body-centered cubic (BCC) phase. As synthesized nanocrystalline Al-Cu-Fe-Ni-Cr HEA demonstrated remarkable hydrogen storage properties, absorbing 2.1 wt.% of hydrogen in 3 minutes at 300°C with 50 atm of hydrogen pressure. At the same temperature, it also desorbed about 1.6 wt.% of hydrogen in 6 minutes. These quick rates of absorption and desorption demonstrate how well the alloy absorbs and releases hydrogen. Additionally, the alloy showed outstanding cyclic stability, retaining almost all of its hydrogen capacity across 25 cycles with only a slight 0.2 wt.% loss. The nanocrystalline Al-Cu-Fe-Ni-Cr HEA is a potential option for hydrogen storage applications due to its outstanding cycle stability and fast kinetics of hydrogen storage and release.

cond-mat.mtrl-sci↗

arXiv2025

Catalytic activity of Al-Cu-Fe-Ni-Cr high entropy alloy

Magnesium hydride (MgH2) is a promising material for hydrogen storage because of its abundance and beneficial properties, such as high storage capacity and cost-effectiveness under mild conditions. Despite of these benefits, MgH2 unfavorable thermodynamics and kinetics make it difficult to use in real applications. In this work, the hydrogen storage properties of MgH2have been improved using Al-Cu-Fe-Ni-Cr high entropy alloy (HEA) based catalysts, which has been synthesized via mechanical alloying. The experimental findings show that the beginning desorption temperature of MgH2significantly lowered from 425°C to 180°C by adding 5 wt. % Al-Cu-Fe-Ni-Cr HEA in MgH2. Moreover, the catalyst shows enhanced kinetics, attaining 7.3 wt. % hydrogen absorption in 3 minutes at 320°C with 15 atm hydrogen pressure, and ~5 wt. % desorption in 6 minutes at 320°C. These results highlight, how much lower its desorption temperature is than those of other well-known catalysts. Over a span of 25 cycles, MgH2 catalyzed by Al-Cu-Fe-Ni-Cr HEA exhibits remarkable cyclic stability with negligible fluctuations (~ 0.05 wt. %).After a thorough characterization of the materials, a workable catalytic mechanism for HEA was proposed in light of the results.

cond-mat.mtrl-sci↗