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Displaying 76 - 100 of 567

Path-integral calculation of the fourth virial coefficient of helium isotopes

March 8, 2021
Author(s)
Giovanni Garberoglio, Allan H. Harvey
We use the path-integral Monte Carlo (PIMC) method and state-of-the-art two-body and three-body potentials to calculate the fourth virial coefficient D(T) of 4He and 3He as a function of temperature from 2.6 K to 2000 K. We derive expressions for the

Transient heating in fixed length optical cavities for use as temperature and pressure standards

February 25, 2021
Author(s)
Jacob Edmond Ricker, Kevin O. Douglass, Jay H. Hendricks, Jack Stone, Sergei Syssoev, Sefer Avdiaj
Optical refractometry techniques can enable realization of both pressure and temperature directly from properties of the gas. For achieving the highest possible accuracy, temperature uniformity across the refractometer must be less than 1 mK. However, the

A system for probing Casimir energy corrections to the condensation energy

December 28, 2020
Author(s)
Diego J. Perez, Alexander Stange, Richard Lally, Lawrence Barrett, Matthias Imboden, Abhishek Som, David Campbell, Vladimir Aksyuk, David Bishop
In this article, we present a nano-electromechanical system (NEMS) designed to detect changes in the Casimir Energy. The Casimir effect is a result of the appearance of quantum fluctuations in the electromagnetic vacuum. Previous experiments have used nano

Reappraising the appropriate use of a common meteorological quantity: Potential Temperature

December 15, 2020
Author(s)
Manuel Baumgartner, Ralf Weigel, Ulrich Achatz, Allan H. Harvey, Peter Spichtinger
The potential temperature is a widely used quantity in atmospheric science since it is conserved for air's adiabatic changes of state. Its definition involves the specific heat capacity of dry air, which is traditionally assumed as constant. However, the

New refrigerants and system configurations for vapor compression refrigeration

November 13, 2020
Author(s)
Mark O. McLinden, Christopher J. Seeton, Andy Pearson
The high global warming potential (GWP) of current refrigerants in cooling equipment based on the vapor-compression cycle has triggered a major effort to find and implement more environmentally benign alternatives. Here, we review the basics of the vapor

Quasiuniversal Excess Entropy Scaling in Binary Supercooled Liquids

August 27, 2020
Author(s)
Ian H. Bell, Jeppe Dyre, Trond Ingebrigtsen
Transport coefficients, such as viscosity or diffusion coefficient, show significant dependence on density or temperature near the glass transition. Although several theories have been proposed for explaining this dynamical slowdown, the origin remains to

Parallel Prefetching for Canonical Ensemble Monte Carlo Simulations

August 25, 2020
Author(s)
Harold Wickes Hatch
In order to enable large-scale molecular simulations, algorithms must efficiently utilize multi-core processors that continue to increase in total core count over time with relatively stagnant clock speeds. Although parallelized molecular dynamics (MD)

The (R)Evolution of Refrigerants

July 2, 2020
Author(s)
Mark O. McLinden, Marcia L. Huber
As we enter the "fourth generation" of refrigerants, we consider the evolution of refrigerant molecules, the ever-changing constraints and regulations that have driven the need to consider new molecules, and the advancements in the tools and property

Compact 1.7 K Cryocooler for Superconducting Nanowire Single-Photon Detectors

June 18, 2020
Author(s)
Vincent Y. Kotsubo, Joel N. Ullom, Sae Woo Nam
State-of-the-art superconductor-based cryogenic detector systems are being installed at numerous research facilities worldwide and are achieving world-record sensitivities in a variety of applications. Implementation has been greatly facilitated by closed
Displaying 76 - 100 of 567