作者：
MCNICHOLS, RJDAVIS, CBRoger J. McNichols is a professor of industrial engineering at the University of Toledo (Department of Industrial Engineering
University of Toledo Toledo OH 43606). After receiving his Ph.D in industrial engineering from The Ohio State University he joined the faculty of Texas A and M University where he directed the Maintainability Engineering Graduate Program at Red River Army Depot. At UT he has served as associate dean of engineering and as chairman of the Systems engineering doctoral program. His research and consulting interests include reliability quality control manufacturing mathematical modeling and applied statistics. Charles B. Davis is an associate professor of mathematics at the University of Toledo (Department of Mathematics
University of Toledo Toledo OH 43606). After receiving his M.S. in mathematics and statistics and his Ph.D. in statistics from the University of New Mexico he joined the Mathematics Department at UT where he established the graduate program in statistics. His research and consulting interests include statistical modeling statistical computation simultaneous inference and data analysis.
Ground water monitoring presents interesting statistical challenges, including controlling the risk of entering compliance monitoring, incorporating all modes of inherent variability into the statistical model on whic...
Ground water monitoring presents interesting statistical challenges, including controlling the risk of entering compliance monitoring, incorporating all modes of inherent variability into the statistical model on which tests are based, and taming the detection limit problem, all while maintaining demonstrable sensitivity to real contamination. Some of these challenges exceed textbook statistics considerably, even when considered alone, and good solutions are scarce. When these challenges are combined, the task of developing good statistical procedures or good regulations can be formidable. This article presents a number of realities of ground water monitoring that should be considered when developing statistical procedures. Recommendations made for addressing these realities include the following: (1) the false positive rate should be controlled on a facility-wide basis, rather than per well or per parameter as required in the proposed regulation (40 CFR §264); (2) multiple comparisons with control procedures are preferable to analysis of variance (ANOVA) for controlling the overall false positive rate; (3) retests can be made an explicit part of the statistical procedure in order to increase power and decrease sensitivity to distribution shape assumptions; (4) commonly used simple methods of handling below detection limit data with parametric tests, including Cohen's procedure as implemented in the U.S. EPA's Technical Enforcement Guidance Document (TEGD), should probably be avoided; (5) the statistical properties of practical quantitation limits for non-naturally occurring compounds should be studied carefully; and (6) so long as the facility-wide false positive rate is controlled, better sensitivity to real contamination is obtained by monitoring fewer well-chosen parameters at a smaller number of well-chosen locations. An evaluation of the proposed revised §264 regulation with respect to these realities reveals that it seems to be a definite improvement over the
Analytical results are obtained for mobility functions which describe the hydrodynamic interactions between two unequal viscous drops. It is assumed that the surface tension is sufficiently high so that the drops reta...
Analytical results are obtained for mobility functions which describe the hydrodynamic interactions between two unequal viscous drops. It is assumed that the surface tension is sufficiently high so that the drops retain a spherical shape. Exact solutions are introduced for the velocity images for Stokeslets and higher‐order Stokes singularities near a viscous drop and then these image solutions are used to generate expressions valid for all two‐sphere geometries except those for which the gap is much smaller than the diameter of the smaller drop. For rigid spheres, these results are used to obtain a closed‐form expression for the Stokes–Einstein Brownian diffusion coefficient.
A new sufficient condition for uniqueness is applied to the tubular reactor problem. The resulting criterion is compared to existing criteria. Better a‐priori estimates of the temperature solution were used to improv...
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Modular scintillation cameras are gamma cameras with relatively small crystal faces, a small number of photomultiplier tubes (PMTs), and independent processing electronics. Our prototypical module has a 10 cm square c...
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With the growing use of macromolecular fluids in modern technology, the need to incorporate the study of flows of these fluids in a standard course on fluid mechanics is almost a necessity. In this note, we would like...
Properties of some double-chained surfactants which form spontaneous thermodynamically stable unilamellar vesicles in water are reviewed and analysed in terms of current ideas on self-assembly and recent direct force ...
Properties of some double-chained surfactants which form spontaneous thermodynamically stable unilamellar vesicles in water are reviewed and analysed in terms of current ideas on self-assembly and recent direct force measurements. The reasons for the apparent success of older theories are discussed. The conclusion is that the older description in terms of primitive model double-layer theory, van der Waals, and additional hydration forces has to be abandoned for a rigorous theory of self-assembly. That conclusion does not abrogate the usefulness of the present theoretical framework in providing a predictive rationale for many systems and in biological problems. This is illustrated by the use of cationic surfactants as immunosuppressants, bacteriocides and other applications.
作者：
CROOKE, PSTANNER, RDPARK, DHDepartment of Mathematics Vanderbilt University Nashville
TN 37235 Philip S. Crooke:is Associate Professor of Mathematics at Vanderbilt University
Nashville TN. He received a B.S. degree (1966) from Stevens Institute of Technology and a Ph.D. in applied mathematics (1970) from Cornell University. He has held positions at Lamont Geological Observatory of Columbia University and Digital Equipment Corporation. He was a visiting scholar at the Center for Applied Mathematics of Cornell University (1982). His research interests include mathematical modeling partial differential equations and isoperimetric inequalities. Department of Chemical Engineering Vanderbilt University Nashville
TN 37235 Robert D. Tanner:is Professor of Chemical Engineering at Vanderbilt University
Nashville TN. He has B.S.E. degrees in mathematics and chemical engineering (1961 1962) and a M.S.E. in chemical engineering (1963) from The University of Michigan. His Ph.D. in chemical engineering (1967) was from Case Western Reserve University. He has held positions at Diamond Shamrock Corp. (1963) and Merck and Co. (1967–72). Visiting professorships include Riken (Japan) in 1980 and ETH-Zürich (Switzerland) in 1981–82. His research interests comprise both experimental and mathematical modeling studies offer-mentation processes. Don-Hee Park:is Assistant Professor of Chemical Engineering at Chonnam National University in Kwang Ju
Korea. He has B.S. (1974) and M.S. (1977) degrees in chemical engineering from Yonsei University in Scoul and is presently a Ph.D. candidate at the same university. He was at The Korea Institute for Industrial Economics and Technology from (1977–78) and was a visiting scholar at Vanderbilt University (1983–85).
The yield function of .**GRAPHIC**. for an enzyme-substrate kinetic model of the system, E + S .**GRAPHIC**. + P, is investigated. Considering Y to be a function of the substrate concentration S, its value as S .fwdar...
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The yield function of .**GRAPHIC**. for an enzyme-substrate kinetic model of the system, E + S .**GRAPHIC**. + P, is investigated. Considering Y to be a function of the substrate concentration S, its value as S .fwdarw. O+ is investigated. In the "pseudo-steady-state domain," this differential yield function is shown to be bounded above and below by yield functions that are obtained by using the Michaelis-Menten and Briggs-Haldane functions to relate the enzyme-substrate concentration C to S. It is also shown that the yield constant, which is commonly used for enzyme and fermentation systems, is an integral average of the differential yield function. The average yield constant can be used to show consistency of data by relating the area above and below the average yield line when the yield function is plotted against the substrate concentration. The role of the dimensionless parameter, .epsilon. = km/E*, on the asymptotic yield, Y (.epsilon. = .**GRAPHIC**. is also investigated. The mathematical results are demonstrated on experimental data for a horseradish-peroxidase enzyme system and a gluconic acid fermentation process.
Results of direct numerical simulations of the decay of nearly isotropic turbulence exhibit clearly that much of the flow evolves in orientation to a state in which the vorticity vector is nearly aligned with the velo...
Results of direct numerical simulations of the decay of nearly isotropic turbulence exhibit clearly that much of the flow evolves in orientation to a state in which the vorticity vector is nearly aligned with the velocity vector.
Mobility measurements were made for dry-ground mica particles dispersed in aqueous KCl, Cr(NO3)3, and cetyltrimethylammonium bromide (CTAB) solutions. In the latter solutions charge reversal occurred at about 2 ×...
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Mobility measurements were made for dry-ground mica particles dispersed in aqueous KCl, Cr(NO3)3, and cetyltrimethylammonium bromide (CTAB) solutions. In the latter solutions charge reversal occurred at about 2 × 10-6 M and 3 × 10-5 M, respectively. Negative zeta potentials in KCl solutions calculated using the Smoluchowski equation are about one third of the corresponding values obtained from streaming potentials and force measurements using mica sheets. Good agreement, however, was obtained when positively charged groups created during grinding were neutralized, and the zeta potentials were corrected according to the procedure of O’Brien and White with an assumed average particle size of 0.25 μm. When the zeta potentials of positively charged particles were corrected in this way, agreement with values calculated from force measurements was also improved.
A mass-transfer model has been developed to explain the adsorption of dyestuffs (Acid Blue 25 and Basic Blue 69) onto various adsorbents in agitated batch adsorbers. The model is based on two resistances, namely, exte...
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