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Search Publications by: George Mulholland (Assoc)

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Displaying 1 - 25 of 103

Improved Accuracy for Calibrated Mass Distribution Measurements of Bimetallic Nanoparticles

May 23, 2022
Author(s)
Kaleb Duelge, George Mulholland, Antonio Montoro Bustos, Michael Zachariah, Michael Zachariah, John Pettibone
Implementation of hybrid nanoparticles (HNPs), consisting of two different metal components, into applied systems has been hindered by an incomplete understanding of structural and chemical properties responsible for their enhanced, yet inconsistent

Detection of Smoke From Microgravity Fires

October 12, 2021
Author(s)
D L. Urban, DeVon Griffin, Gary Ruff, Thomas Cleary, Jiann C. Yang, George W. Mulholland, Zeng-guang Yuan
The history and current status of spacecraft smoke detection is discussed including a review of the state of understanding of the effect of gravity on the resultant smoke particle size. The results from a spacecraft experiment (Comparative Soot Diagnostics

Evaluation of Spacecraft Smoke Detector Performance in the Low-Gravity Environment

April 25, 2018
Author(s)
Jiann C. Yang, Thomas G. Cleary, Marit Meyer, D L. Urban, George W. Mulholland, Victoria Bryg, Zeng-guang Yuan, Gary A. Ruff
In the interest of fire prevention, most materials used in the interior construction of manned spacecraft are non- flammable, however, they do produce smoke when overheated. Spacecraft smoke detectors will ideally detect smoke generated by oxidative

Microgravity Superagglomerates Produced by Silane and Acetylene

February 19, 2017
Author(s)
Matthew Bundy, George Mulholland, Samuel Manzello, Jiann C. Yang, J H. Scott
A study of acetylene and silane diffusion flames was performed in normal gravity (1-g) and microgravity ([mu]-g) to determine the evolution of soot and silica agglomerates. The objective of this study was to understand the process of gas phase

Modeling, Measurement, and Standards for Wafer Inspection

February 19, 2017
Author(s)
George Mulholland, Thomas A. Germer, J C. Stover
The major technical issues regarding the calibration of Surface Scanning Inspection Systems (SSIS) are presented including descriptions of the salient features of SSISs and the deposition system using the differential mobility analyzer. The role of the

Moment Method for Obtaining Particle Size Measures of Test Smokes

February 19, 2017
Author(s)
Thomas Cleary, D W. Weinert, George Mulholland
The number concentration, ionization chamber output, and mass concentration were recorded continuously for five different test smokes generated in the fire emulator/detector evaluator. The number and the mass concentrations are direct measures of the

NIST Calibration Facility for Sizing Spheres Suspended in Liquids

February 19, 2017
Author(s)
Michelle K. Donnelly, George Mulholland, Michael R. Winchester
A calibration facility has been developed to measure the peak diameter of particles suspended in liquid using differential mobility analysis (DMA). A description of the facility and the features that contribute to measurements with low uncertainties is

Smoke Characterization and Feasibility of the Moment Method for Spacecraft Fire Detection

February 17, 2015
Author(s)
Jiann C. Yang, Thomas G. Cleary, George W. Mulholland, Marit Meyer, Victoria Bryg, D L. Urban, Zeng-guang Yuan, Gary A. Ruff
The Smoke Aerosol Measurement Experiment (SAME) has been conducted twice by NASA and provided the first real-time aerosol data in a spacecraft micro-gravity environment. Flight experiment results have recently been analyzed with respect to comparable

Pyrolysis Smoke Generated Under Low-Gravity Conditions

January 17, 2015
Author(s)
Jiann C. Yang, Thomas G. Cleary, George W. Mulholland, D L. Urban, Gary A. Ruff, Zeng-guang Yuan, Marit Meyer, Victoria Bryg
A series of smoke experiments were carried out in the Microgravity Science Glovebox on the International Space Station (ISS) Facility to assess the impact of low-gravity conditions on the size distribution and structure of the smoke aerosol. This

Characterizing Heat Release Rate Transients

April 26, 2012
Author(s)
Rodney A. Bryant, Erik L. Johnsson, George W. Mulholland
A series of experiments was performed to characterize the time response of a large-scale open calorimeter to square-wave pulses in terms of peak heat release rate, width of the peak, and conservation of energy. Quantitative heat release rate measurements

Amplification of the optical absorption cross section for aerosols of soot with a nonabsorbing coating from photoacoustic measurements

May 13, 2011
Author(s)
Pedro Bueno, Daniel K. Havey, George W. Mulholland, Joseph T. Hodges, Keith A. Gillis, Russell R. Dickerson, Michael R. Zachariah
A quantitative understanding of the absorption and scattering properties of mixed soot and aerosol particles is necessary for evaluating the Earth's energy balance. Uncertainty in the net radiative forcing of atmospheric aerosols is relatively large and

Verification of a Gas Mask Calibrant

February 19, 2007
Author(s)
Robert A. Fletcher, Jiann C. Yang, George W. Mulholland, R L. King, Michael R. Winchester, D Klinedinst, Jennifer R. Verkouteren, Thomas G. Cleary, David Buckingham, James J. Filliben

Measurement of 100 nm and 60 nm Particle Standards by Differential Mobility Analysis

August 1, 2006
Author(s)
George W. Mulholland, Michelle K. Donnelly, Robert C. Hagwood, S R. Kukuck, Vincent A. Hackley, D Y. Pui
The peak particle size and expanded uncertainties (95 % confidence interval) for two new particle calibration standards are measured as 101.60 nm ? 1.02 nm and 60.68 nm ? 0.59 nm. The particle samples are polystyrene spheres suspended in filtered

Report of Experimental Results for the International Fire Model Benchmarking and Validation Exercise #3.

December 1, 2005
Author(s)
Anthony P. Hamins, Alexander Maranghides, Erik L. Johnsson, Michelle K. Donnelly, Jiann C. Yang, George W. Mulholland, Robert Anleitner
The Nuclear Regulatory Commission (NRC) and the National Institute of Standards and Technology (NIST) are participating in an International Collaborative Fire Model Project (ICFMP) to assess and validate fire computer codes for nuclear power plant

Experiments and Modeling of Structural Steel Elements Exposed to a Fire. Federal Building and Fire Safety Investigation of the World Trade Center Disaster (NIST NCSTAR 1-5B) ***DRAFT for Public Comments***

September 1, 2005
Author(s)
Anthony P. Hamins, Alexander Maranghides, Kevin B. McGrattan, Erik L. Johnsson, Thomas J. Ohlemiller, Michelle K. Donnelly, Jiann C. Yang, George W. Mulholland, Kuldeep R. Prasad, S R. Kukuck, Robert Anleitner, Therese P. McAllister
Reconstructing the fires and their impact on structural components in the World Trade Center (WTC) buildings on September 11, 2001, requires extensive use of computational models. For the use of such models to be a viable investigative tool, it is