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Physics

Thermodynamics

Search Publications

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  • Published Date
Displaying 1 - 25 of 437

Entropic modulation of divalent cation transport

September 22, 2025
Author(s)
Yechan Noh, Demian Riccardi, Alexander Smolyanitsky
Aqueous cations permeate subnanoscale pores by crossing free energy barriers dominated by competing enthalpic contributions from transiently decreased ion-solvent and increased ion-pore electrostatic interactions. This commonly accepted view is rooted in

Rayleigh-Taylor instability in a binary quantum fluid

August 27, 2025
Author(s)
Ian Spielman, Gretchen Campbell, Stephen Eckel, Yanda Geng, Junheng Tao, Mingshu Zhao, Shouvik Mukherjee
We experimentally investigated the Rayleigh-Taylor instability in an immiscible homogeneous Bose-Einstein condensate (BEC) in different spin states. A magnetic field gradient force pushes two BECs together and induces instability of the interface, leading

Demonstration of dispersion gas barometry

June 17, 2025
Author(s)
Yuanchao Yang, Jack Stone, Patrick Egan
Realization of the optical pascal has been limited by systematic errors caused by distortion of the optic. In this work, distortion error is circumvented via synchronous measurement of helium refractivity at two optical frequencies. The resultant pressure

Partition Functions and Ideal-Gas Thermodynamics for Carbon Dioxide

June 10, 2025
Author(s)
Sergey Tashkun, Allan Harvey
We have constructed an effective Hamiltonian model for the rotational-vibrational states of molecular carbon dioxide. The model is constrained by a large amount of spectroscopic data for frequencies of rovibrational transitions. From this formulation, we

Compact Blackbody Radiation Atomic Sensor: Measuring Temperature using Optically Excited Atoms in Vapor Cells

April 17, 2025
Author(s)
David La Mantia, Mingxin Lei, Nikunjkumar Prajapati, Noah Schlossberger, Matthew Simons, Christopher Holloway, Julia Scherschligt, Stephen Eckel, Eric Norrgard
We demonstrate a blackbody radiation thermometer based on optically excited rubidium atoms in a vapor cell. Operating as a calibrated contact thermometer from 308K to 343 K, we realize temperature uncertainty as low as 0.04 %, and statistical temperature

Refrigerant Properties Development R&D: Final Report to U.S. Department of Energy on Interagency Agreements 892434-19-S-EE000031 and 892434-23-S-EE000120

March 31, 2025
Author(s)
Mark McLinden, Katrina Avery, Ala Bazyleva, Ian Bell, Tara Fortin, Marcia Huber, Andrei Kazakov, Eric Lemmon, Stephanie Outcalt, Richard Perkins, Elizabeth Rasmussen, Demian Riccardi, Aaron Rowane
The HVAC&R industry is facing the challenge of phasing down the use of the HFC (hydrofluoro-carbon) refrigerants. New energy-efficient refrigerants are required, and accurate property data for them are needed to design and operate new HVAC equipment using

Computational and Theoretical Study of Colloidal Monolayers with Short-Range Attractions and Dipolar Repulsions

March 21, 2025
Author(s)
Chieh-Chih Yeh, Harold Hatch, Adithya Sreenivasan, Bhuvnesh Bharti, Vincent Shen, Zachary Sherman, Thomas Truskett
This study explores the structure and phase behavior of monolayers of model colloids with short-range attractions and long-range repulsions, The model is motivated by recent experiments of hard-sphere-like microspheres that effectively interact via

NIST Neutron Source Pre-Conceptual Design

February 10, 2025
Author(s)
David Diamond, Abdullah Weiss, Osman Celikten, Jeremy Cook, Dagistan Sahin, Hubert King, Anil Gurgen, Joy Shen
A pre-conceptual design has been completed for a NIST Neutron Source (NNS). It would replace the existing facility at the NIST Center for Neutron Research (NCNR) to enable significantly more thermal and cold neutrons to be used in many more experiments

Traceable Comparisons of Water-Triple-Point Cells

November 8, 2024
Author(s)
Weston L. Tew
A specific sub-set of comparison data is presented for two NIST water-triple-point cells that provide traceability to the results of the 2023 Consultative Committee for Thermometry CCT-K7.2021 CIPM Key Comparison of Water-Triple-Point Cells. NIST had

Comparison of Three Methods for Oscillating Flow Measurements in Cryocoolers

October 16, 2024
Author(s)
Ryan Snodgrass, Vincent Kotsubo, Joel Ullom
Measurement of oscillating mass flows is typically required for the study of cryocoolers and cryocooler compressors. Although many measurement techniques are used in the cryocooler literature, detailed comparisons are lacking, so it can be challenging for

Speed of Sound for Understanding Metals in Extreme Environments

October 7, 2024
Author(s)
Elizabeth Rasmussen, Boris Wilthan
Knowing material behavior is crucial to successful design, especially given the growing number of next-generation energy, defense, and manufacturing systems operating in extreme environments. Specific applications for materials in extreme environments

Linking excess entropy and acentric factor in spherical fluids

September 9, 2024
Author(s)
Tae Jun Yoon, Ian Bell
Introduced by Kenneth Pitzer in 1955, the acentric factor (ω) became a standard quantity in chemical thermodynamics, representing a molecule's "shape" effect on the deviation from the corresponding state behavior. Nevertheless, its interpretation remains

Anisotropic coarse-grain Monte Carlo simulations of lysozyme, lactoferrin, and NISTmAb by precomputing atomistic models

September 5, 2024
Author(s)
Harold Hatch, Christina Bergonzo, Marco Blanco, Guangcui Yuan, Sergei Grudinin, Mikael Lund, Joseph E. Curtis, Alexander Grishaev, Yun Liu, Vincent K. Shen
We develop a multiscale coarse-grain model of the NIST Monoclonal Antibody Reference Material 8671 (NISTmAb) to enable systematic computational investigations of high-concentration physical instabilities such as phase separation, clustering, and

Monte Carlo molecular simulations with FEASST version 0.25.1

September 5, 2024
Author(s)
Harold Hatch, Daniel Siderius, Vincent K. Shen
FEASST is an open-source Monte Carlo software for particle-based simulations. This software, which was released in 2017, has been used to study phase equilibrium, self-assembly, aggregation or gelation in biological materials, colloids, polymers, ionic

Optical n(p, T_90) measurement suite 2: H_2O and D_2O

May 28, 2024
Author(s)
Patrick Egan, Yuanchao Yang
A suite of measurements of refractive index n(p, T_90) is reported for gas phase ordinary water H_2O and heavy water D_2O. The methodology is optical refractive index gas metrology, operating at laser wavelength 633 nm and covering the range (293 T_90 43
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