пятница, 28 марта 2025 г.

sciencedirect: Commissioning of the neutron irradiation station at the University of Notre Dame

 

Full length article
Commissioning of the neutron irradiation station at the University of Notre Dame

, , , , , , , ,
Department of Physics and Astronomy, University of Notre Dame, Notre Dame, IN 46556-5670, USA

Received 15 July 2024, Revised 3 March 2025, Accepted 4 March 2025, Available online 15 March 2025, Version of Record 18 March 2025.

Abstract

Cross section data for neutron-induced reactions are needed for applications in nuclear astrophysics, stockpile stewardship, and nuclear reactor design but often contain discrepancies and gaps. A neutron source with a high neutron flux, a well-characterized neutron energy distribution, and a wide range of available neutron energies is ideal for studying such reactions in order to improve on existing data and provide new experimental results. For this purpose, the Neutron Irradiation Station (NIS) was developed using the
Li(p,n)Be reaction. Neutron energy profiles were obtained using He spectrometers and neutron standards were used to determine the neutron flux using the activation method. The neutron energy profile was found to be quasi-monoenergetic and neutrons were produced at energies from 1 keV to 1 MeV. The flux at the production target was found to be (1.42+_ 0.20)*10^-8 s−1cm−2.

 

 https://doi.org/10.1016/j.nima.2025.170406

sciencedirect: Design strategy of high-entropy perovskite energy-storage ceramics: A review

 

Design strategy of high-entropy perovskite energy-storage ceramics: A review

, , , , ,
School of Materials Science and Engineering, Shaanxi University of Science & Technology, Xi’an 710021, China

Received 3 December 2023, Revised 22 January 2024, Accepted 18 February 2024, Available online 20 February 2024, Version of Record 15 March 2024.

 

Abstract

With the increasing demand for high energy density and reliable dielectric capacitors in the field of power electronics, the research and manufacture of ceramic capacitor materials face significant challenges. At present, the traditional design ideas of dielectric ceramic materials have gradually formalized, and the system is complex and similar, whether it can design dielectric ceramic materials with high performance from a new viewpoint and explore the underlying mechanism remains a great challenge. This paper is based on ceramic capacitors with high energy storage performance, a series of high-entropy perovskite oxide ceramics designed by the concept of "entropy engineering" in the past five years are reviewed. The relationship between microstructure and macroscopic energy storage performance of materials is discussed based on the four effects of high-entropy ceramics. We predict that "entropy engineering" will be a successful strategy to break through the bottleneck of dielectric materials with high energy storage performance. This review guides the custom design of composition-structure-properties in high-entropy energy storage ceramics.

 https://doi.org/10.1016/j.jeurceramsoc.2024.02.040

среда, 26 марта 2025 г.

Chronicles of a Trumpastrophe 5: Disease prevention programs have been cancelled and state funding for libraries and science museums has been eliminated

 

Trump cuts damage global efforts to track diseases, prevent outbreaks

Disease surveillance programs worldwide are suddenly in limbo

 A project to track and contain menacing animal viruses across seven countries, from avian influenza in poultry to Lassa virus in rodents, ended with a single email. In late January, Jonathon Gass, an epidemiologist and virologist at Tufts University, was about to leave for Bangladesh to close out an effort to monitor and combat avian influenza, when the emailed letter arrived from the U.S. Agency for International Development (USAID), ordering an immediate halt to work on the $100 million STOP Spillover project. Gass, a co-deputy director of the project, stayed in Massachusetts and started to call staff around the world to tell them to drop everything. One colleague monitoring Lassa virus in Liberia was driving to a field site. “I had to tell him that he needed to turn the car around, come back, and book a plane ticket home,” Gass says.

 read more:  https://www.science.org/content/article/trump-cuts-damage-global-efforts-track-diseases-prevent-outbreaks

 

***

 

Trump order could wipe out federal support for U.S. science museums

Institute of Museum and Library Services now run by Department of Labor as part of proposed dismantling

 Pinedale, Wyoming, only has 2034 residents. But no town is too small for the traveling FlexCart operated by the Science Zone, a modest science museum serving residents of the most rural state in the continental United States.

read more:  https://www.science.org/content/article/trump-order-could-wipe-out-federal-support-u-s-science-museums

пятница, 21 марта 2025 г.

science.org: We started our Ph.D.s during COVID-19. Now, we’re graduating into political chaos

 

 Five years ago, I got the email I had hoped for. “We are very pleased to offer you admission to the Neuroscience Ph.D. program,” it read, as confetti in the school’s colors rained down the screen. My parents didn’t have college degrees. I didn’t meet someone with a Ph.D. until college—and now I was going to be one, training in my first-choice program. My friend and I decided to celebrate by making some homemade mac ’n cheese, and we headed to the grocery store for milk. But there was none: The date was 13 March 2020, and COVID-19 had been declared a pandemic 2 days before. Now, I’m nearing graduation in another time of crisis—hoping to draw strength from the lessons I learned the first time around.

 read more: https://www.science.org/content/article/we-started-our-ph-d-s-during-covid-19-now-we-re-graduating-political-chaos

 

my comment:  I think that just sitting and waiting for improvement is a bad position. If there is an opportunity to find a job in a commercial company or a startup related to scientific research, then you should try to get a job there. If possible, equip your garage, as described in the article by Nature (https://www.nature.com/articles/467634a), to do home research as a hobby, or maybe for non-governmental grants, in collaboration with your university. Your own laboratory in the garage is a guarantee that your equipment and developments will not be thrown out one "fine" day. More complex research related to dangerous and licensed actions must be carried out in large scientific centers in collaboration with them.

среда, 19 марта 2025 г.

Chronicles of a Trumpastrophe 4: Cancellation of subscriptions to scientific journals for the national library of the Department of Agriculture and reduction of funding for the fight against AIDS

 

DOGE order leads to journal cancellations by U.S. agricultural library

“We can’t do science without these,” one researcher says of the hundreds of journals no longer accessible

 https://www.science.org/content/article/doge-order-leads-journal-cancellations-u-s-agricultural-library

 

 

Outgoing head of heralded U.S. global HIV/AIDS program urges Trump to reverse cuts

John Nkengasong, who had helmed PEPFAR since 2022, says “history will remember we showed humanity”

https://www.science.org/content/article/outgoing-head-heralded-u-s-global-hiv-aids-program-urges-trump-reverse-cuts

пятница, 14 марта 2025 г.

t-invariant: “If DOGE plans go through, U.S. scientific leadership will end.” American scientist – on Musk’s health care reform

 “If DOGE plans go through, U.S. scientific leadership will end.” American scientist – on Musk’s health care reform

 

In the coming days, the US Senate is expected to confirm Jay Bhattacharya as the new director of the National Institute of Health. This decision is awaited not only by the staff of the organization and scientists of the United States. The key institution of American science has been subjected to purges and pressure from the Department of Government Efficiency (DOGE), which is headed by entrepreneur and billionaire Elon Musk. Why the reforms initiated by Donald Trump’s people are reminiscent of the situation in Germany in the 1930s and how the DOGE plans threaten the development of advanced science – this was told to T-invariant on condition of anonymity by the head of one of the laboratories of the National Institute of Health.

 

пятница, 7 марта 2025 г.

sciencedirect: Influence of AC fields and electrical conduction mechanisms on the flash-onset temperature: Electronic (BiFeO3) vs. ionic conductors (8YSZ)

 

Influence of AC fields and electrical conduction mechanisms on the flash-onset temperature: Electronic (BiFeO3) vs. ionic conductors (8YSZ)

a
Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Calle Américo Vespucio 49, Sevilla, 41092, Spain
b
Departamento de Química Inorgánica, Facultad de Química, Universidad de Sevilla, Sevilla, 41012, Spain

Received 27 February 2022, Revised 21 June 2022, Accepted 22 June 2022, Available online 1 July 2022, Version of Record 22 March 2023.

 

Abstract

This work aims to clarify the influence of AC (up to 50 kHz) vs DC fields on the flash-onset temperature, emphasizing the role of the electrical conduction mechanism. BiFeO3 (BFO) is used as an example of electronic conductor while 8-mol % Yttria-stabilized zirconia (8YSZ) is used as an example of ionic conductor. For 8YSZ, a frequency dependence of the flash-onset temperature and flash-induced heating is observed. This is consistent with the different contributions found in the total electrical response of 8YSZ as characterized by impedance spectroscopy measurements. Estimations based on the blackbody radiation model suggest that 8YSZ samples attain higher temperatures under AC fields due to a more efficient heating. Moreover, a noticeable decrease in the activation energy for the electrical conduction after the flash is triggered is attributed to electronic conduction. Meanwhile, the lack of frequency response and insensitiveness to the type of electrical field found in the case of BFO can be attributed to its mainly electronic bulk conduction.
 


sciencedirect: Flash sintering improves magnetic properties of spinel zinc ferrite

 

Scripta Materialia

Volume 236, November 2023, 115681
Scripta Materialia

Flash sintering improves magnetic properties of spinel zinc ferrite

Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India

Received 11 June 2023, Revised 20 July 2023, Accepted 22 July 2023, Available online 28 July 2023, Version of Record 28 July 2023.

 

Abstract

We report on a simple protocol for one step synthesis and sintering of single-phase magnetic spinel ZnFe2O4 zinc ferrite (ZFO) using an electric field assisted sintering. The resultant materials show improved saturation magnetization and higher coercivity compared to conventionally sintered ferrite. The changes in properties have been attributed to generation of non-thermal lattice defects when processed under electric field. Instead of using the high temperatures (>1000 °C) and extended dwell periods (> 4 h) required by the traditional sintering processes, this method permits sintering of ZFO at a furnace temperature of only 950 °C in just a minute by applying a minimal field of 25 Vcm−1. This magnetic material with decreased coercivity and increased saturation magnetization will improve the efficiency of solenoids, transformer/inductor cores, microwave devices and magnetic shields.
 

среда, 5 марта 2025 г.

Chronicles of a Trumpastrophe 3: Sticker shock: New U.S. tariffs could raise cost of research equipment and supplies

 

Sticker shock: New U.S. tariffs could raise cost of research equipment and supplies

China, Canada, and Mexico are major suppliers of essential scientific items

The tariffs imposed today by the United States on its three largest trading partners could not only drive up the cost of goods for U.S. consumers, but also hit researchers by raising prices for scientific equipment.

read more:  https://www.science.org/content/article/sticker-shock-new-u-s-tariffs-could-raise-cost-research-equipment-and-supplies

суббота, 1 марта 2025 г.

Chronicles of a Trumpastrophe 2

 1. Trump Tracker. Recent: What happened to FDA’s meeting to pick the next seasonal flu vaccine?    28 Feb 2025 By Science News Staff

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


2.  Trump credit card freeze sparks alarm at health agencies. “Cost efficiency” order could block travel, supplies for labs and patient care.  27 Feb 20256:00 PM ET By Meredith Wadman, Jocelyn Kaiser

https://www.science.org/content/article/trump-credit-card-freeze-sparks-alarm-health-agencies


Science: First petawatt electron beam arrives, ready to rip apart matter and space

 

First petawatt electron beam arrives, ready to rip apart matter and space

Ultra–high-power particle pulses could boost x-ray science and laboratory astrophysics

read more: https://www.science.org/content/article/first-petawatt-electron-beam-arrives-ready-rip-apart-matter-and-space 

 ***
 
My comment: This is a surprising thing for me, although the physics is very clear. This is the ability to cause nuclear reactions with subthreshold (essentially optical, non-nuclear) electromagnetic radiation. Only due to the high intensity of light, and therefore high voltages of the electrical component.


sciencedirect: Flash sintering of complex shapes

Applied Materials Today
Volume 26, March 2022, 101293

Flash sintering of complex shapes


Charles Manière a b 1 2, Geuntak Lee a 1, Eugene A. Olevsky a 1

a    Powder Technology Laboratory, San Diego State University, San Diego, United States of America

b    Normandie Univ, ENSICAEN, UNICAEN, CNRS, CRISMAT, Caen, France

Received 1 September 2021, Revised 16 November 2021, Accepted 24 November 2021, Available online 7 December 2021, Version of Record 7 December 2021.

 

Highlights

  • Flash spark plasma sintering scalability.
  • Interface method for spark plasma complex shaping.
  • Flash sintering of complex shapes.

Abstract

Flash (ultra-rapid) sintering of powder materials is a Multiphysics phenomenon which has a potential for the quasi-instantaneous fabrication of various components. However, the intrinsic instability of flash sintering makes it difficult to apply to complex shapes and large specimens. Here, we circumvent this problem by the use of an interface-controlled approach to impose stable and very fast heating to large powder samples which become fully dense in a matter of seconds. The Multiphysics simulation demonstrated that an electric-thermal-mechanical confinement of the specimen allows a very efficient (and selective) heating and sintering of the powder specimen with a homogeneous microstructure and a substantial reduction of the grain growth. Our results indicate that the ultra-rapid sintering of large and complex shape samples is possible.

 https://www.sciencedirect.com/science/article/pii/S2352940721003565