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Search Publications by: Boris Wilthan (Assoc)

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Displaying 1 - 14 of 14

Reference Correlations for the Density and Thermal Conductivity, and Review of the Viscosity Measurements, of Liquid Titanium, Zirconium, Hafnium, Vanadium, Niobium, Tantalum, Chromium, Molybdenum, and Tungsten

January 22, 2024
Author(s)
Eleftheria Ntonti, Sofia Sotiriadou, Marc Assael, Marcia L. Huber, Boris Wilthan, Manabu Watanabe
The available experimental data for the density, thermal conductivity, and viscosity of liquid titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten have been critically examined with the intention of establishing

Detection of Dense, Overlapping, Geometric Objects

July 1, 2020
Author(s)
Adele P. Peskin, Boris Wilthan, Michael P. Majurski
Using a unique data collection, we are able to study the detection of dense geometric objects in image data where object density, clarity, and size vary. The data is a large set of black and white images of scatterplots, taken from journals reporting

Time-Resolved Absorptance and Melt Pool Dynamics during Intense Laser Irradiation of a Metal

October 25, 2018
Author(s)
Brian J. Simonds, Jeffrey W. Sowards, Joshua A. Hadler, Erik A. Pfeif, Boris Wilthan, Jack R. Tanner, Paul A. Williams, John H. Lehman
Laser welding is a complex, dynamic process by which focused, high-intensity laser light is used to join two metallic surfaces and is being increasing deployed in a variety of industrial applications. Determining the time-dependent absorptance of the laser

Dynamic and absolute measurements of laser coupling efficiency during laser spot welds

September 3, 2018
Author(s)
Brian J. Simonds, Jeffrey W. Sowards, Joshua A. Hadler, Erik A. Pfeif, Boris Wilthan, Jack R. Tanner, Chandler Harris, Paul A. Williams
Laser absorptance (coupling efficiency) changes rapidly during laser metal processing due to temperature and multiple phase changes. We find that there is limited literature data available, but this property is vital for accurate process simulations, as

Data Resources for Thermophysical Properties of Metals and Alloys, Part 1: Structured Data Capture from the Archival Literature

January 7, 2017
Author(s)
Boris Wilthan, Erik A. Pfeif, Vladimir Diky, Robert D. Chirico, Ursula R. Kattner, Kenneth G. Kroenlein
In support of the continuous scientific and industrial need for accessible and high-quality thermophysical property data for metals and alloy systems, NIST/TRC is expanding its data archiving and critical evaluation activities to include this area. As part

Report on the CCT Supplementary Comparison S1 of Infrared Spectral Normal Emittance/Emissivity

March 15, 2016
Author(s)
Leonard M. Hanssen, Boris Wilthan, Christian Monte, Joerg Hollandt, Jacques Hameury, Jean-Remy Filtz, Ferruccio Girard, Mauro Battuello, Juntaro Ishii
The National Measurement Institutes (NMIs) of the United States, Germany, France, Italy and Japan, have joined in an inter-laboratory comparison of their infrared spectral emittance scales. This action is part of a series of supplementary inter-laboratory

Absorption and Reflection of Infrared Radiation by Polymers in Fire-Like Environments

July 17, 2012
Author(s)
Gregory T. Linteris, Mauro Zammarano, Boris Wilthan, Leonard M. Hanssen
In large-scale fires, the input of energy to burning materials occurs predominantly by radiative transfer. The in-depth absorption of radiant energy by a polymer influences its ignition time and burning rate. The present investigation examines two methods

An absolute cavity pyrgeometer to measure the absolute outdoor longwave irradiance with traceability to International System of Units, SI

March 1, 2012
Author(s)
Ibrahim Reda, Jinan Zeng, Jonathan Scheuch, Leonard Hanssen, Daryl Myers, Boris Wilthan, Tom Stoffel
This article describes a method of measuring the absolute outdoor longwave irradiance using an absolute cavity pyrgeometer (ACP). The ACP consists ofa domeless thermopile pyrgeometer, gold- plated concentrator, temperature controller, and data acquisition

A Determination Study of The Cavity Emissivity of the Eutectic Fixed Points Co-C, Pt-C and Re-C

December 5, 2011
Author(s)
Leonard M. Hanssen, Yohsiro Yamada, Pieter Bloembergen, Pablo Castro, Boris Wilthan, Sergey Mekhontsev
The eutectics Co-C, Pt-C and Re-C, with phase transition temperatures of 1597 K, 2011 K, and 2747 K, respectively, are presently investigated for their suitability to serve as reference points for dissemination of T (and T90) within the context of the

Absorption of Thermal Radiation by Burning Polymers

February 2, 2011
Author(s)
Gregory T. Linteris, Mauro Zammarano, Boris Wilthan, Leonard M. Hanssen
In large-scale fires, the input of energy to burning materials occurs predominantly by radiative transfer. The in-depth absorption of radiant energy by a polymer influences its ignition time and burning rate. The present investigation examines two methods