J. R. Mehaffey

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George Hadjisophocleous

Carleton University

Robert I. Cukier

Michigan State University

Raymond Kapral

University of Toronto

T. Z. Harmathy

Michigan State University

Peng Lei

Marine Design & Research Institute of China

Mohammad Mohammad

Abu Dhabi National Oil (United Arab Emirates)

Rashmi C. Desai

University of Toronto

Steven Craft

Carleton University

O. Burkan Isgor

Oregon State University

I. M. Van Zeeland

Carleton University

Cooperative Institutions

Carleton University

National Research Council Canada

University of Toronto

Intertek (Canada)

University of New Brunswick

Michigan State University

Atomic Energy (Canada)

Huazhong University of Science and Technology

National Academies of Sciences, Engineering, and Medicine

Marine Design & Research Institute of China

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Microscopic theory of condensed phase chemical reactions. II. Configuration space equations

The Journal of Chemical Physics (1980)

Robert I. Cukier Raymond Kapral J. R. Mehaffey Ki-Bong Shin

Configuration space equations for the description of reactive pair dynamics are obtained from the pair phase space kinetic equations derived in the preceding paper. These configuration space equations are generalizations of the conventional ’’sink’’ Smoluchowski equations. In addition to displaying the modifications in Smoluchowski equation descriptions due to velocity relaxation effects, computationally tractable expressions for the diffusion and friction tensors are obtained. The structure of the rate kernel which follows from the phase space kinetic equation is also examined.

Smoluchowski coagulation equation

Kernel (algebra)

Configuration space

10.1063/1.439329

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Citations (14)

Kinetic theory of the hydrodynamic interaction between two particles

The Journal of Chemical Physics (1981)

Robert I. Cukier Raymond Kapral J. R. Mehaffey

A kinetic theory derivation of the hydrodynamic interaction between two massive, large spheres in a dilute gas is presented. The calculations start from microscopic expressions for the two particle diffusion and friction tensors obtained from a pair kinetic equation. The hydrodynamic expression for the friction tensor is obtained as an expansion in the ratio of particle diameter σ to particle separation r12 to order (σ/r12)3. This calculation displays the microscopic collision mechanisms which are responsible for the viscous drag and hydrodynamic interaction experienced by the particles.

Kinetic Theory

Particle (ecology)

10.1063/1.441318

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Citations (17)

Kinetic theory of self-diffusion in a hard-sphere fluid

Physical review. A, General physics (1978)

Robert I. Cukier J. R. Mehaffey

A repeated-ring kinetic equation for the velocity-autocorrelation function in a hard-sphere fluid is presented. In this theory contributions from uncorrelated (Enskog) collisions, correlated (single-ring) collisions, and multiple (repeated-ring) collisions are included. A quasihydrodynamic approximation is made to describe the intermediate propagation between correlated collisions. We obtain an expression for the self-diffusion coefficient $D$ which suggests that its density dependence arises from a competition between the shear and density fluctuations of the fluid. Using interpolation formulas to numerically evaluate the coupling of the test-particle motion to the fluid fluctuations we have computed $D$. The variation of $D$ with density is found to be in good qualitative agreement with computer molecular-dynamics simulation. For low to moderate density the coupling of the test-particle motion to the fluid shear (vortex) fluctuations leads to an enhancement of $D$ relative to its Enskog value. At high density the coupling to the fluid-density fluctuations yields a sharp decrease in $D$.

Kinetic Theory

Test particle

10.1103/physreva.18.1202

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Citations (40)

Predicting the thermal response of gypsum board subjected to a constant heat flux

Fire and Materials (2008)

Steven Craft O. Burkan Isgor George Hadjisophocleous J. R. Mehaffey

Abstract Models are available to predict the fire‐resistance ratings of wood‐frame assemblies protected by gypsum board. These models have been developed to predict the performance of assemblies exposed to a standard fire test in which temperatures increase monotonically. In an ongoing effort to model the fire resistance of light‐frame wood floor assemblies, in this study, a number of improvements over past heat transfer models have been made in an attempt to simulate assembly performance in any arbitrary fire exposure. For this purpose, the heat transfer analysis has been coupled with a mass transfer analysis. The calcination of gypsum board and pyrolysis of wood are now modelled using an Arrhenius expression. In order to evaluate the accuracy of the model, a series of cone calorimeter experiments have been conducted in an effort to generate experimental data under well‐defined boundary conditions. Comparisons between test results and the predictions from a one‐dimensional heat and mass transfer analysis are encouraging with excellent agreement in predicting the point at which gypsum board is fully calcinated. A lack of material property data, particularly the permeability of gypsum board, remains a limiting factor in further improvement of the accuracy of the model. Copyright © 2008 John Wiley & Sons, Ltd.

Cone calorimeter

Fire test

10.1002/fam.971

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Citations (36)

A probability-based Monte Carlo life-risk analysis model for fire emergencies

Fire Safety Journal (2017)

Xia Zhang Xiao Li J. R. Mehaffey George Hadjisophocleous

10.1016/j.firesaf.2017.02.003

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Citations (18)

Dynamical correlations in rough sphere fluids

Chemical Physics Letters (1977)

J. R. Mehaffey Rashmi C. Desai Raymond Kapral

10.1016/0009-2614(77)80279-0

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Citations (2)

Fire resistance performance of unprotected wood–wood–wood and wood–steel–wood connections: A literature review and new data correlations

Fire Safety Journal (2010)

Peng Lei George Hadjisophocleous J. R. Mehaffey Mohammad Mohammad

Eurocode

Engineered wood

Fire performance

Solid wood

Cross laminated timber

10.1016/j.firesaf.2010.08.003

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Citations (27)

Wood-frame residential buildings in Canada.

J. R. Mehaffey

Source

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Citations (0)

The normalized heat load concept and its use

Fire Safety Journal (1987)

T. Z. Harmathy J. R. Mehaffey

Heat load

10.1016/0379-7112(87)90017-8

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Citations (16)

Failure probabilities of constructions designed for fire resistance

Fire and Materials (1984)

J. R. Mehaffey T. Z. Harmathy

Abstract ‘Normalized heat load’ is a quantifier of the destructive potential of fires, real‐world compartment fires and test fires alike. For real‐world fires it is subject to some uncertainties owing to the random nature of two of the variables it depends on: ventilation and fire load. For test fires also it is subject to uncertainties owing to a moderate degree of randomness that characterizes the results of test fires. A procedure is described for predicting the failure probability in fire of the boundaries of a compartment designed for fire resistance on the basis of information concerning the characteristics of the compartment and the design value of the fire load. The procedure is essentially deterministic, employing statistical considerations only as far as required by the nature of some of the input variables. With the aid of second‐moment analysis, it is possible, furthermore, to design the compartment boundaries for appropriate target failure probabilities.

10.1002/fam.810080207

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Citations (9)