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Search Publications by: Vladimir B. Khromchenko (Fed)

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Displaying 1 - 10 of 10

Non-nulling Protocols for Fast, Accurate, 3-D Velocity Measurements in Stacks

July 28, 2023
Iosif Isaakovich Shinder, Aaron Johnson, James Filla, Vladimir B. Khromchenko, Michael R. Moldover, Joey Boyd, John D. Wright, John R. Stoup
We present protocols for making fast, accurate, 3-D velocity measurements in the stacks of coal-fired power plants. The measurements are traceable to internationally-recognized standards; therefore, they provide a rigorous basis for measuring and/or

Comparison of saturator designs for low volatility liquid precursor delivery

April 1, 2023
James E. Maslar, William A. Kimes, Vladimir B. Khromchenko, Brent Sperling, Ravindra Kanjolia
Low volatility precursors are widely utilized in chemical vapor deposition and atomic layer deposition processes. Such precursors are often delivered from one of two common saturator designs: a bubbler or a flow over vessel. Previous reports concerning

Measurement Uncertainty of Surface Temperature Distributions for Laser Powder Bed Fusion Processes

August 10, 2021
David Deisenroth, Sergey Mekhontsev, Brandon Lane, Leonard M. Hanssen, Ivan Zhirnov, Vladimir Khromchenko, Steven Grantham, Daniel Cardenas-Garcia, Alkan Donmez
This paper describes advances in measuring the characteristic spatial distribution of surface temperature and emissivity during laser-metal interaction under conditions relevant for laser powder bed fusion (LPBF) additive manufacturing processes. Detailed

Facility for calibrating anemometers as a function of air velocity vector and turbulence

July 19, 2021
Iosif Isaakovich Shinder, Michael R. Moldover, James Filla, Aaron Johnson, Vladimir B. Khromchenko
NIST calibrates anemometers as a function of airspeed vector and turbulence intensity (Tu). The vector capability (sometimes called '3D') is particularly important for calibrating multi-hole differential-pressure probes that are often used to quantify

Measurements of Melt Pool Geometry and Cooling Rates of Individual Laser Traces on IN625 Bare Plates

February 5, 2020
Brandon M. Lane, Jarred C. Heigel, Richard E. Ricker, Ivan Zhirnov, Vladimir Khromchenko, Jordan S. Weaver, Thien Q. Phan, Mark R. Stoudt, Sergey Mekhontsev, Lyle E. Levine
The complex physical nature of the laser powder bed fusion (LPBF) process warrants use of multiphysics computational simulations to predict or design optimal operating parameters or resultant part qualities such as microstructure or defect concentration

Characterization of Five-Hole Probes used for Flow Measurement in Stack Emission Testing

May 16, 2018
Iosif Isaakovich Shinder, Aaron Johnson, Michael R. Moldover, James Filla, Vladimir Khromchenko
We report progress towards the goal of reducing the errors in industrial smokestack flow measurements to 1 % by replacing S-probes with calibrated 3-D probes (i.e., probes that measure 3 components of velocity). NIST calibrated a commercially-manufactured

Comparison of laser-based and monochromator-based thermodynamic temperature measurements

March 19, 2012
George P. Eppeldauer, Howard W. Yoon, Jorge E. Neira, Vladimir Khromchenko, Charles E. Gibson, Allan W. Smith
In this work, we describe the comparisons between the laser-based and monochromator-based radiance responsivity calibrations of a radiation thermometer. The spectral selection of the radiation thermometer is performed using a photopic-response filter which

Extension of the NIST spectral power-responsivity calibration service to 2500 nm

March 2, 2012
George P. Eppeldauer, Howard W. Yoon, Jinan Zeng, Thomas C. Larason, Jeanne M. Houston, Vladimir Khromchenko
The National Institute of Standards and Technology (NIST) is working to extend the upper wavelength limit of the spectral power-responsivity calibration service from 1800 nm to 2500 nm. This extension is based on extended-InGaAs (EIGA) transfer- and

Spectroradiometric Characterization of the NIST Pulsed Solar Simulator

August 20, 2009
Howard W. Yoon, Brian P. Dougherty, Vladimir Khromchenko
The spectroradiometric characterization of the NIST indoor pulsed solar simulator is described. The solar simulator has a flash duration of 36.4 ms and is designed for solar panels having a maximum size of 2.0 m by 1.6 m. As per industry standards, the