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Based on a set of multi-scale computer models, an equation is developed for predicting the chloride ion diffusivity of concrete as a function of water-to-cement (w/c) ratio, silica fume addition, degree of hydration, and aggregate volume fraction. Silica
D W. Stroup, Laurean A. DeLauter, J Lee, G Roadarmel
Rate of heat release is a critical parameter for evaluation of the fire properties of a material. The Large Fire Research Facility at the National Institute of Standards and Technology operates three hoods capable of determining heat release rate from
An experimental program is undertaken to enhance the knowledge base regarding seismic design of precast concrete shear walls. The emulation design and jointed design philosophies are described, and an idealization of the behavior of precast shear walls is
This paper examines the performance of R-22 and its possible replacements in an air-cooled air conditioner. The study focuses on the effect ofelevated outdoor temperatures on system capacity and Coefficient of Performance (COP). The refrigerants considered
X-ray absorption equipment and concurrent mass measurements are used in quantifying water movement in 4 to 5 mm thick cement paste specimens with their top surface exposed to drying. Experimental variables examined in this preliminary study include water
S El-Borgi, Michael A. Riley, Fahim H. Sadek, N Ayed
Numerous studies have been conducted so far on active or hybrid (active/passive) control of hysteretic structures using a wide range of linear and nonlinear control algorithms. However, most research work on the use of semi-active control systems has been
Kenneth A. Snyder, Chiara C. Ferraris, Nicos Martys, Edward Garboczi
The suitability of using the initial current from the rapid chloride test (ASTM C 1202) to determine specimen conductivity is tested using impedance spectroscopy with a frequency spectrum of 10 Hz to 1 MHz. The specimen conductivity has an analytical
The main objective is to provide technical support (literature review on water additives, fluid property and possibly droplet impact data) for the study of the dynamics of droplet/surface and droplet/flame interaction and its effect on burning cessation to
The National Institute of Standards and Technology (NIST) is improving its resource allocation process by doing microstudies of its research impacts on society. This report is one of a series of microstudies prepared by NIST s Building and Fire Research
The National Institute of Standards and Technology (NIST) is conducting a study to advance the science of measuring and modeling the optical scattering properties of materials. Results of measurements and mathematical models for quantifying light
This manual describes the use of the computer program CONTAMW developed by NIST. CONTAMW is a multizone indoor air quality and ventilation analysis program designed to help you determine: air flows--infiltration, exfiltration, and room-to-room air flows in
Thomas J. Ohlemiller, John R. Shields, Roy A. McLane, Richard G. Gann
This study addresses the fire behavior of bed assemblies, including a mattress, foundation and bedclothes. The focus is on development and application of a reproducible means of simulating the thermal impact which burning bedclothes materials impose on a
Dale P. Bentz, O M. Jensen, A M. Coats, Frederik P. Glasser
Experimental and computer modeling studies are applied to determining the influence of silica fume on the microstructure and diffusivity of cement paste. It is suggested that silica fume modifies the inherent nanostructure of the calcium silicate hydrate
To attempt to represent concrete properly as a composite material, one must consdier at least three phases: matrix, aggregates, and the interfacial transition zone (ITZ), a thin shell of altered matrix material surrounding each aggregate grain. Assigning
Mark R. VanLandingham, John S. Villarrubia, G F. Meyers
Regardless of the type of test, reliable indentation measurements require knowledge of the shape of the indenter tip. For indentation measurements involving sub-micrometer scale contacts, accurate knowledge of the tip shape can be difficult to achieve. In
Arthur H. Fanney, Robert R. Zarr, J D. Ketay-Paprocki
This paper presents the results of a study aimed at quantifying the performance of water heaters insulated with polyurethane foams using three different blowing agents - HCFC-141b, H2O/CO2, and HFC-245fa. The thermal conductivity of the foam was measured
K L. Mcnesby, R T. Wainner, A W. Miziolek, W M. Jackson, I A. McLaren
A sensor for measurement of vapors from the hydrocarbon-based fuels JP-8, DF-2, and gasoline is described. The sensor is based upon a previously reported laser mixing technique that uses two tunable diode lasers emitting in the near-infrared spectral
Valeri I. Babushok, R T. Wainner, K L. Mcnesby, R G. Daniel, A W. Miziolek
In this work. we repoil the results of experimental and con1put:itioiial studies on inhibition and extinction of opposed-flow propane (C&)-air tlaines by DMMP (CxH.,OIP). as well as N? and FM-200 (CIF7H) as reference inhibitors. For the dilute flame
Rodney A. Bryant, Marcia L. Huber, William M. Pitts
As part of the National effort to identify effective replacements for halon fire suppressants, NIST has been investigating whether highly effective thermal agents are feasible. Thermal agents are defined as those that obtain their effectiveness solely by
In practical fire suppression systems for large rooms or compartments, water sprinklers are often located on or near the ceilings. In this configuration, the droplets from the water spray must be large enough to penetrate the high temperature thermal plume