воскресенье, 23 февраля 2025 г.

Chronicles of a Trumpastrophe: Mass firings decimate U.S. science agencies

 science

Mass firings decimate U.S. science agencies

White House dismissals and rationale challenged by dismissed scientists and lawsuits

 On 13 February, a research entomologist at the U.S. Department of Agriculture (USDA) was among the first, receiving an email after the close of business hours saying they were being “removed” from what they describe as a dream job, studying a key problem in agriculture science. The change had gone into effect 14 minutes before the email arrived. “The letter said I was being let go due to poor performance, which is nonsensical since they invited me to apply for a promotion just the other month,” the stunned researcher says.

read more:  https://www.science.org/content/article/mass-firings-decimate-u-s-science-agencies

sciencedirect: A novel Multi‐Phase Flash Sintering (MPFS) technique for 3D complex‐shaped ceramics

 Applied Materials Today 26 (2022) 101274

A novel Multi-Phase Flash Sintering (MPFS) technique for 3D complex-shaped ceramics

Sandra Molina-Molina a,1, Eva Gil-González a,b,1,∗, Francisco José Durán-Olivencia c,
José Manuel Valverde d, Antonio Perejón a,e, Pedro E. Sánchez-Jiménez a,e,∗,
Luis A. Pérez-Maqueda a,∗

Highlights

  • First demonstration of enhanced flash sintering by a rotating electric field.
  • Larger power densities allow for reduced sintering temperatures.
  • A wide variety of ceramics can be more efficiently sintered by MPFS.
  • Homogeneous sintering is attainable even for complex-shaped specimens.

Abstract

This work demonstrates the first proof-of-concept of Multi-Phase Flash Sintering (MPFS). This novel technique essentially consists of applying a rotating electric field to the sample by means of a multi-phase voltage source as furnace temperature increases. Several ceramic materials with different types of electrical conductivities are sintered within seconds at furnace temperatures much lower than those used for traditional DC flash sintering due to the higher power densities administered by a multi-phase power supply. Thus, ceramic materials are flashed at relatively lower applied voltages which minimizes undesired phenomena such as localization and preferential current pathways. Furthermore, MPFS allows diverse electrode configurations to promote a more uniform electric field distribution, enhancing the sintering of 3D complex-shaped specimens. MPFS could be a true breakthrough in materials processing, as 3D complex-shaped specimens are homogeneously sintered at reduced temperatures, while keeping all the advantages of conventional flash sintering.


https://www.sciencedirect.com/science/article/pii/S2352940721003371

четверг, 20 февраля 2025 г.

science: Trump Tracker

 

Trump Tracker

Latest on firings: Protest outside HHS headquarters

Recent Trackers: NSF’s firing maneuver | HHS protest | Indirect costs for dummies
Story tips, internal Trump administration or science agency emails, or other key documents?  Contact us


19 Feb 2025, 6:10 PM ET

‘Brazen defiance.’ Are Trump officials obeying an order to unfreeze foreign aid?

President Donald Trump’s administration says it is within its rights to continue an extensive freeze on foreign aid, despite being told to lift the blockade by a federal judge. But administration opponents say that claim is “brazen defiance” of the judge’s order.

Read more: https://www.science.org/content/article/science-trump-latest-news

пятница, 14 февраля 2025 г.

Ceramics International: Expanding the scope of multiphase-flash sintering: Multi-dogbone configurations and reactive processes

 

Ceramics International

Volume 50, Issue 14, 15 July 2024, Pages 25210-25215
 
 

Expanding the scope of multiphase-flash sintering: Multi-dogbone configurations and reactive processes

A.F. Manchón-Gordón a
, S. Molina-Molina a, A. Perejón a b, A. Alcalde-Conejo a, P.E. Sánchez-Jiménez a b, L.A. Pérez-Maqueda a

a
    Instituto de Ciencia de Materiales de Sevilla, ICMSE CSIC-Universidad de Sevilla, C. Américo Vespucio 49, Sevilla, 41092, Spain

b
    Departamento de Química Inorgánica, Facultad de Química, Universidad de Sevilla, 41012, Sevilla, Spain

Received 1 March 2024, Revised 5 April 2024, Accepted 19 April 2024, Available online 20 April 2024, Version of Record 3 June 2024.
 

Abstract

In this work, we have expanded the possibilities of the multiphase-flash sintering (MPFS) technique by investigating several configurations that involve multiple dogbone specimens (ranging from 1 to 3) and multiple phases (also ranging from 1 to 3). Unlike the traditional MPFS approach using complex 3D or cylindrical samples, this new method allows for a direct comparison with the established conventional flash sintering technique. Our experimental results with dense 8-mol% Yttria-stabilized zirconia demonstrate a significant reduction in the onset temperature as the number of phases and dogbones increases. Building on these findings, we achieved the preparation of pure bulk specimens of SrFe12O19 for the first time through reactive multiphase-flash sintering.
 
 

Vacuum: Investigation of intense pulsed ion beam generation by a magnetically insulated ion diode at a reduced impedance

 

Vacuum

Volume 217, November 2023, 112496

 

Investigation of intense pulsed ion beam generation by a magnetically insulated ion diode at a reduced impedance

Marat Kaikanov, Dosbol Nauruzbayev, Alshyn Abduvalov, Kanat Baigarin

    Nazarbayev University, Astana, 010000, Kazakhstan

Received 22 March 2023, Revised 9 August 2023, Accepted 10 August 2023, Available online 11 August 2023, Version of Record 14 August 2023.

 

Abstract

The intense pulsed ion beam (IPIB) generation was investigated at reduced impedance of a magnetically insulated ion diode. The main goal of our research was to obtain IPIB with adjustable parameters at low current densities. The diode impedance was varied by the external magnetic field current by setting the delay of the accelerator's trigger relative to the launch of the magnetic field generator. The B-applied ion diode adjustably generated IPIB with a current density in the range from 25 to 4 A/cm2. In the matched mode the accelerator generates the ion beam with a current density of about 100 A/cm2. Obtained results of the IPIB current density adjustment allows to irradiate samples in a single vacuum cycle without the change of charging voltage of both magnetic field and accelerating voltage generators. Gold films with a thickness of 10 nm deposited on fluorine-doped tin oxide (FTO)/glass substrates were irradiated to demonstrate the applicability of obtained IPIB for irradiation of thin coatings without their deterioration. Single shot of IPIB with current density of 20 A/cm2 transformed Au film to spherical micro-particles, while after irradiation at the same fluence with 5 pulses of IPIB with current density of 4 A/cm2 Au coating was preserved as a film.
 

Ceramics International: Influence of the atmosphere on the formation of high-entropy oxides within the Co–Cu–Fe–Mg–Mn–Ni–O system via reactive flash sintering

 

Ceramics International

Volume 50, Issue 21, Part B, 1 November 2024, Pages 42276-42285
 

Influence of the atmosphere on the formation of high-entropy oxides within the Co–Cu–Fe–Mg–Mn–Ni–O system via reactive flash sintering

 A.F. Manchón-Gordón a, C. Lobo-Llamas a, S. Molina-Molina a, A. Perejón a b
, P.E. Sánchez-Jiménez a, L.A. Pérez-Maqueda a

a
    Instituto de Ciencia de Materiales de Sevilla, ICMSE CSIC-Universidad de Sevilla, C. Américo Vespucio 49, Sevilla, 41092, Spain

b
    Departamento de Química Inorgánica, Facultad de Química, Universidad de Sevilla, Sevilla, 41012, Spain

Received 8 May 2024, Revised 22 July 2024, Accepted 4 August 2024, Available online 5 August 2024, Version of Record 27 September 2024.
 

Abstract

In this study, the feasibility of preparing quinary equimolar high-entropy oxides within the Co–Cu–Fe–Mg–Mn–Ni–O system was explored using the reactive flash sintering (RFS) technique. Various compositions were tested using this technique under atmosphere pressure, leading to the formation of two primary phases: rock-salt and spinel. Conversely, a new high-entropy oxide was produced as a single-phase material with the composition (Co0.2,Cu0.2,Mg0.2,Mn0.2,Ni0.2)O when RFS experiments were conducted in nitrogen atmosphere. The reducing conditions achieved in nitrogen enabled the incorporation of cations with oxidation states different from +2 into the rock-salt lattice, emphasizing the critical role of the processing atmosphere, whether inert or oxidizing, in the formation of high-entropy oxides. The electrical characterization of this material was obtained via impedance spectroscopy, exhibiting a homogeneous response attributed to electronic conduction with a temperature dependence characteristic of disordered systems.
 

понедельник, 10 февраля 2025 г.

ScienceAdvances: Electric plasma guided with ultrasonic fields

 

Electric plasma guided with ultrasonic fields

Science Advances
5 Feb 2025
Vol 11, Issue 6
 
Electric plasma forms sparks in midair that transfer electrical current. This current can power high-voltage electronics, kill bacteria, produce tactile sensations, or be used for welding. However, the formation of the spark is chaotic and hard to control. Laser pulses can guide discharges but require high power and are disruptive and cumbersome to control. Here, we show that ultrasonic fields can guide plasma sparks, even around obstacles. The ultrasonic beams can be directed dynamically and within milliseconds, enabling precise, nondangerous, and fast control of high-voltage sparks. This phenomenon can be used for applications in high-voltage switching and plasma treatments.
 

воскресенье, 9 февраля 2025 г.

ScienceAdvances: 187Os nuclear resonance scattering to explore hyperfine interactions and lattice dynamics for biological applications

187Os nuclear resonance scattering to explore hyperfine interactions and lattice dynamics for biological applications

Science Advances
7 Feb 2025
Vol 11, Issue 6

Abstract

Osmium complexes with osmium in different oxidation states (II, III, IV, and VI) have been reported to exhibit antiproliferative activity in cancer cell lines. Herein, we demonstrate unexplored opportunities offered by 187Os nuclear forward scattering (NFS) and nuclear inelastic scattering (NIS) of synchrotron radiation for characterization of hyperfine interactions and lattice dynamics in a benchmark Os(VI) complex, K2[OsO2(OH)4]. We determined the isomer shift [δ = 3.3(1) millimeters per second] relative to [OsIVCl6]2− and quadrupole splitting [ΔEQ = 12.0(2) millimeters per second] with NFS. We estimated the Lamb-Mössbauer factor [0.80(4)], extracted the density of phonon states, and carried out a thermodynamics characterization using the NIS data combined with first-principles calculations. Overall, we provide evidence that 187Os nuclear resonance scattering is a reliable technique for the investigation of hyperfine interactions and Os-specific vibrations in osmium(VI) species and is thus applicable for such measurements in osmium complexes of other oxidation states, including those with anticancer activity such as Os(III) and Os(IV).
 
 https://www.science.org/doi/10.1126/sciadv.ads3406

суббота, 1 февраля 2025 г.

RASA-USA: Statement in Support of Professor Yulia Sineokaya

 

Statement in Support of Professor Yulia Sineokaya

We express our unconditional support for Professor Yulia Sineokaya, a member of our association, Corresponding Member of the Russian Academy of Sciences, Doctor of Philosophy, and Director of the Independent Institute of Philosophy, which was recently designated an “undesirable organization” in the Russian Federation.

The work of Yulia Sineokaya and her colleagues makes a significant contribution to preserving Russian philosophical thought and humanism in a global context. Their activities are rooted in the principles of free inquiry and intellectual integrity, which are fundamental to any academic tradition.

We stand in solidarity with Yulia Sineokaya and her colleagues in their commitment to advancing knowledge and fostering dialogue, even under challenging circumstances. We are confident that their efforts will continue to inspire and resonate both within Russia and beyond its borders.

The Board of Directors
Russian-American Science Association

 

https://rasa-usa.org/en/news/statement-support-professor-sineokaya/

Science: Compact, cheaper, laser-powered particle accelerators get real

 

Compact, cheaper, laser-powered particle accelerators get real

Little powerhouses might someday replace billion-dollar, kilometer-long behemoths at major x-ray facilities

An elegant new concept may be about to revolutionize the technology of particle acceleration, which animates huge atom smashers and x-ray sources. For decades, some physicists have strived to develop an accelerator powered by laser light that would be much smaller and cheaper than existing machines. Recent progress suggests laser plasma accelerators (LPAs) may soon realize that bright promise.

read more:

https://www.science.org/content/article/compact-cheaper-laser-powered-particle-accelerators-get-real

Science: Banished from world’s biggest physics lab, Russian scientists look inward—and to China

Banished from world’s biggest physics lab, Russian scientists look inward—and to China

Breakdown of collaboration with CERN forcing many physicists to reorient work

 In the dead of the Russian winter, many of the nation’s physicists are feeling a particular chill. Banished since late last year from Europe’s CERN, the world’s largest particle physics laboratory, and increasingly isolated by trade sanctions that have complicated purchases of scientific equipment, many Russian physicists are having to dramatically reorient their work—with some looking to China for collaboration.

read more:

https://www.science.org/content/article/banished-world-s-biggest-physics-lab-russian-scientists-look-inward-and-china