Dichlorodifluoromethane (R-12) has been widely used as a radiator gas in pressure threshold Cherenkov detectors for high-energy particle physics. However, that compound is becoming unavailable due to the Montreal Protocol. To find a replacement with suitably high refractive index, we use a combination of theory and experiment to examine the polarizability and refractivity of several non-ozone-depleting compounds. Our measurements show that the fourth-generation refrigerants R-1234yf (2,3,3,3-tetrafluoropropene) and R-1234ze(E) (-1,3,3,3-tetrafluoropropene) have sufficient refractivity to replace R-12 in this application. If the slight flammability of these compounds is a problem, two nonflammable alternatives are R-218 (octafluoropropane), which has a high Global Warming Potential, and R-13I1 (trifluoroiodomethane), which has low Ozone Depletion Potential and Global Warming Potential but may not be sufficiently inert.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5998681 | PMC |
| http://dx.doi.org/10.1016/j.nimb.2018.04.006 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Effect of Pressure on Ce-Substituted Nd-Fe-B Hot-Deformed Magnets in the Hot-Pressing Process.
Materials (Basel)
July 2024
Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea.
With the increasing demand for Nd-Fe-B magnets across various applications, the cost-effective substitution of Ce has garnered significant interest. Many studies have been conducted to achieve the high magnetic properties of Nd-Ce-Fe-B hot deformation magnets in which Nd is replaced with Ce. We propose a method to improve magnetic properties of the Ce-substituted Nd-Ce-Fe-B hot-deformed magnets by optimizing the hot-pressing process.
View Article and Find Full Text PDFWhere Lennard-Jones Potentials Fail: Iterative Optimization of Ion-Water Pair Potentials Based on Ab Initio Molecular Dynamics Data.
J Phys Chem Lett
April 2022
Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, 64287 Darmstadt, Germany.
Article Synopsis
- The Lennard-Jones (LJ) potential is commonly used in computer simulations of electrolyte solutions, but struggles with accurately depicting ion hydration due to overly repulsive interactions between ions and water.
- This repulsion causes inaccuracies like blue-shifted vibrational peaks for cations and misleading hydration entropy values.
- Using effective pair potentials informed by ab initio molecular dynamics data provides a better representation of hydration shell properties, suggesting a more effective modeling approach for thermodynamic and local interactions with nonpolarizable force field models.
Fast Evaluation of Two-Center Integrals over Gaussian Charge Distributions and Gaussian Orbitals with General Interaction Kernels.
J Chem Theory Comput
April 2020
Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
We present efficient algorithms for computing two-center integrals and integral derivatives, with general interaction kernels (), over Gaussian charge distributions of general angular momenta . While formulated in terms of traditional ab initio integration techniques, full derivations and required secondary information, as well as a reference implementation, are provided to make the content accessible to other fields. Concretely, the presented algorithms are based on an adaption of the McMurchie-Davidson Recurrence Relation (MDRR) combined with analytical properties of the solid harmonic transformation; this obviates all intermediate recurrences except the adapted MDRR itself, and allows it to be applied to fully contracted auxiliary kernel integrals.
View Article and Find Full Text PDFCandidates to Replace R-12 as a Radiator Gas in Cherenkov Detectors.
Nucl Instrum Methods Phys Res B
June 2018
Engineering Physics Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA.
Dichlorodifluoromethane (R-12) has been widely used as a radiator gas in pressure threshold Cherenkov detectors for high-energy particle physics. However, that compound is becoming unavailable due to the Montreal Protocol. To find a replacement with suitably high refractive index, we use a combination of theory and experiment to examine the polarizability and refractivity of several non-ozone-depleting compounds.
View Article and Find Full Text PDFOperative Results and Clinical Features of Chronic Stanford Type B Aortic Dissection: Examination of 234 Patients Over 6 Years.
Eur J Vasc Endovasc Surg
December 2015
Kawasaki Aortic Center, Kawasaki Saiwai Hospital, Kawasaki, Japan.
Objective/background: Recently, the indications for thoracic endovascular aortic repair (TEVAR) have been expanding, and the applicability of TEVAR for acute type B aortic dissection (TBAD) is proposed with regard to the high mortality of open surgery for chronic TBAD. TEVAR in the acute phase may lead to remodeling of the false lumen (FL), but it is controversial whether it completely resolves the aortic expansion in the chronic phase. In this study, operative results and the relationship between FL status and the time before surgical intervention were retrospectively analyzed.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!