Showing papers by "University of Houston published in 1972"
176 citations
TL;DR: The use of students as subjects in studies of consumer behavior is widespread;1 entire classrooms of potential respondents are readily available to academic researchers at little or no cost as mentioned in this paper. But these advantages obscure the key question: do student responses accurately reflect the behavioral patterns of other consumers?
Abstract: The use of students as subjects in studies of consumer behavior is widespread;1 entire classrooms of potential respondents are readily available to academic researchers at little or no cost. These respondents generally follow instructions rapidly and accurately, and the researcher can claim (at times legitimately) that participating in such studies enriches the students' education. But these advantages obscure the key question: do student responses accurately reflect the behavioral patterns of other consumers? Few would deny that students are consumers, but they typically are psychologically, socially, and demographically different from other segments of the population. The consumer of interest in many marketing studies is the housewife, but the respondents most convenient to marketing professors are, largely, male, undergraduate business students. Are conclusions based on their responses valid when applied to housewives?
111 citations
TL;DR: In this article, the authors defined a dimensionless stability margin which lies between one and zero (steady state in- stability) and is easily computed from a load flow, where the margin of torque is defined as the least change in power flows that will cause instability.
Abstract: The flow function of a power system is the vector of node powers expressed in terms of the node angles The Jacobian is the matrix of partial derivatives of the flow vector with respect to the angle vector The ratio of the determinant of the Jacobian to the value which it has when the node angles are set to zero is a dimensionless stability margin which lies between one and zero (steady-state in- stability) and is easily computed from a load flow The margin of torque is the least change in power flows that will cause instability Maximizing the torque margin or maximizing the stability margin with a load constraint yields the optimum dispatching change to maximize security
106 citations
TL;DR: A pentadecapeptide isolated from the brain of rats trained to avoid the dark has been chemically identified and its structure confirmed by synthesis.
Abstract: A pentadecapeptide isolated from the brain of rats trained to avoid the dark has been chemically identified and its structure confirmed by synthesis. It induces dark avoidance in untrained animals.
89 citations
89 citations
TL;DR: In this article, an experiment centering around a mass spectrometer is described, which is aimed at the identification of organic substances present in the top 10 cm of the surface of Mars and an analysis of the atmosphere for major and minor constituents as well as isotopic abundances.
88 citations
TL;DR: In this paper, a simplified analysis of wall friction and its effect on porosity and permeability is presented, and the effects of stress distribution on the structure and uniformity of the packing are examined.
Abstract: The effect of side-wall friction on the uniformity of packing of beds in compression-permeability cells is examined. A large portion of pressure applied to the top of a compressible bad is absorbed in wall friction, resulting in a nonuniformly packed bed. A simplified analysis of wall friction and its effect on porosity and permeability is presented.
All experimenters involived in flow through porous media are urged to examine the effects of stress distribution on the structure and uniformity of the packing. In general, compressible beds of small particles will be strongly affected by the walls.
87 citations
TL;DR: In this paper, a number of criteria for selecting the best subset of predictor variables in a linear regression model has been reviewed and a cooperative effort to resolve the problem is recommended; however, the properties of these criteria are generally not understood and the relative merits of contending criteria are not clear.
Abstract: The problem of selecting the best subset of predictor variables in a linear regression model has led to the development of a number of criteria for choosing between contending subsets. Unfortunately, the properties of these criteria are generally not understood and the relative merits of contending criteria are not clear. In this note, a number of criteria are reviewed and a cooperative effort to resolve the problem is recommended.
84 citations
TL;DR: In this paper, the center of angle is defined as the inertia weighted average of all rotor angles and the angular velocity of the centre of angle accurately describes the frequency of the system.
Abstract: The evaluation of the stability of a power system during a transient requires that the dynamics of the subsystems be decomposed into relative and collective motions. This decomposition must establish a distinction between synchronous and frequency equilibria. Such a decomposition is made possible by specifying a system center of angle which is defined as the inertia weighted average of all rotor angles. The angular velocity of the center of angle accurately describes the frequency of the system. An angular coordinate of each rotating element in the system can be specified relative to the center of angle. In terms of these coordinates a simple expression is obtained for the exact transient kinetic energy of the system. A transformation relating center of angle referenced variables to the usual one machine reference allows the simultaneous use of both references each where best suited.
84 citations
TL;DR: In this paper, a procedure for locating directly the lowest saddle point of the potential energy function associated with a power transmission network is presented, which is used to compute a margin of stability that specifies the maximum asynchronous transient energy that can be retained by the system while in synchronism.
Abstract: A procedure for locating directly the lowest saddle point of the potential energy function associated with a power transmission network is presented. This procedure is used to compute a margin of stability that specifies the maximum asynchronous transient energy that can be retained by the system while in synchronism. The potential function is shown to be convex in the principal region of the angle space. A unique solution is shown to exist for the load flow problem if the algorithm of solution is initiated at the origin.
61 citations
TL;DR: In this paper, the effect of temperature on the reaction rate of grouped species which are consumed by parallel nth-order irreversible reactions is investigated, and it is shown that when the activation energies of the individual reacting species are aboput equal the temperature effect can be described by an Arrhenius expression.
Abstract: The effect of temperature on the reaction rate of grouped species which are consumed by parallel nth order irreversible reactions is investigated. It is shown that when the activation energies of the individual reacting species is aboput equal the temperature effect can be described by an Arrhenius expression. However, when the activation energies of the various reactions are widely spread the Arrhenius dependence may not be adequate unless one assumes that the activation energy of the lump may be temperature and conversion dependent. Unter these conditions the Arrhenius temperature dependence is at best a rough approximation and it is very important to define exactly the experimental method of determining the activation energy. Widely different activation energies for the pseudocomponent may be obtained from different experimental techniques which yield the same value for a single reactant.
TL;DR: The midgut epithelium of larval and early postlarval brown shrimp has been studied with light and electron microscopy, and electron dense, membrane bound vesicles are consistently seen in association with the Golgi apparatus, apical cell surface, and gut lumen and therefore are believed to be secretory granules.
Abstract: The midgut epithelium of larval and early postlarval brown shrimp has been studied with light and electron microscopy. Ultrastructurally the features of the midgut do not change during these stages of development. On the basis of electron density, two epithelial cell types can be distinguished, and these are referred to as light and dark cells. The dark cells contain more rough endoplasmic reticulum and more free ribosomes than the light cells. Mitochondria in the dark cells have a matrix which is less electron dense than the mitochondrial matrix of the light cells. Both cell types have a microvillous border with a surface coat. The microvilli lack microfilaments within their core, and a terminal web is not differentiated in the stages examined. Tubular smooth endoplasmic reticulum is abundant in the basal portions of the cells. Electron dense, membrane bound vesicles are consistently seen in association with the Golgi apparatus, apical cell surface, and gut lumen and therefore are believed to be secretory granules. Cells in the anterior portion of the midgut often contain very large lipid droplets in the cytoplasm.
TL;DR: In this paper, the authors show that the stress distribution in typical C-P cells is highly non-uniform because of wall friction and that the porosity and permeability would also be nonuniform.
Abstract: Compression-permeability cells are utilized for measurement of porosity and permeability of compressible cakes. Shortcomings of the cells have tended to be minimized in the literature. Data are presented which show that the stress distribution in typical C-P cells is highly nonuniform because of wall friction. For compressible materials, the porosity and permeability would also be nonuniform. Use of large L/D ratios and minimizing wall friction are essential to proper use of C-P cells.
TL;DR: Testicular cysts located within the mesoglea of the mesenteries of Bunodosoma cavernata contain cells in all spermatogenic and spermiogenic stages and are associated with a cytoplasmic collar which surrounds the anterior region of the tail.
TL;DR: In this article, the polymerization of silicic acid has been investigated at a pH of 8.5 and initial monomer concentration of 300 p.p.m. The rate of polymerization was determined at 25, 30, 35, 40 and 45°C so that the activation energies could be calculated.
TL;DR: In larval and early postlarval brown shrimp, Penaeus aztecus, portions of the branchial chamber are lined by a tissue which appears ultrastructurally to be modified for osmoregulation.
Abstract: In larval and early postlarval brown shrimp, Penaeus aztecus , portions of the branchial chamber are lined by a tissue which appears ultrastructurally to be modified for osmoregulation. The distribution of this tissue, the larval stages in which it occurs, and its appearance with the light and electron microscope are presented. The significance of the distribution and ultrastructure of this modified tissue is discussed.
TL;DR: Some meteoritic chondrules are also formed by impact processes such as crystallization after shock melting and abrasion and diffusion in base-surge and fall-back deposits generated by impacts on planetary surfaces.
Abstract: Chondrules have been observed in several breccia samples returned by the Apollo 14 mission. These lunar chondrules are believed to have formed during a large impact event, perhaps the one that formed the Imbrian Basin. This suggests that some meteoritic chondrules are also formed by impact processes such as crystallization after shock melting and abrasion and diffusion in base-surge and fall-back deposits generated by impacts on planetary surfaces.
TL;DR: An improved mode of representation for networks resulting from process simulation flowcharts is presented based on the signal flowgraph concept, which is applicable to equation-ordering problems if the output set is selected a priori.
TL;DR: A model of the U.S. petroleum refining industry, where a linear programming specification of the production function determines crude oil input requirements, the output of by-products, and the utilization of capacity is described.
Abstract: The linking of statistically estimated relationships with an engineering linear programming model offers important potentials for simulation and forecasting models of industries. This article describes such a model of the U.S. petroleum refining industry. Econometric techniques are used to specify product demands, prices, and some technical adjustments. A linear programming specification of the production function, assuming cost minimization, determines crude oil input requirements, the output of by-products, and the utilization of capacity. As applications of the model, a sample period calculation and a five-year forecast are presented along with a discussion of alternative cases and forecast error.
TL;DR: The three regions of a muscle insertion (cuticle, epidermis and muscle) are discussed for the larval forms of the decapod, Penaeus aztecus, and a modified epidermal cell located in the branchiostegite of the larvals shrimp is discussed.
Abstract: Fine structural observations on muscle insertion in arthropods are extended to the order Decapoda. The three regions of a muscle insertion (cuticle, epidermis and muscle) are discussed for the larval forms of the decapod, Penaeus aztecus . These regions are contrasted to muscle insertions of insects and arachnids which have been previously reported in the literature. In addition, a modified epidermal cell located in the branchiostegite of the larval shrimp is discussed. The epidermal cell of the branchiostegite is modified in a manner similar to the epidermis of the muscle insertion. The two epidermal cell types are contrasted and the significance of their modifications is discussed.
01 Jan 1972
TL;DR: Chondrules have been observed in several breccia samples and one fine sample returned by the Apollo 14 mission as discussed by the authors, which is consistent with the interpretation that both the Fra Mauro formation and the Apennine Front material originated as ejecta from the Imbrian event.
Abstract: Chondrules have been observed in several breccia samples and one fines sample returned by the Apollo 14 mission. The chondrules are formed by at least three different processes that appear to be related to large impacts: (1) crystallization of shock-melted spherules and droplets; (2) rounding of rock clasts and mineral grains by abrasion in the base surge; and (3) diffusion and recrystallization around clasts in hot base surge and fall-back deposits. In the case of the Apollo 14 samples, the large impact almost certainly is the Imbrian event. Grain size analyses of undisturbed fines samples from the Apollo 14 site and from the Apollo 15 Apennine Front are almost identical, indicating that the two localities have similar meteoroid bombardment exposure ages, approximately 3.7 x 10 to the 9th yr. This observation is consistent with the interpretation that both the Fra Mauro formation and the Apennine Front material originated as ejecta from the Imbrian event.
TL;DR: In this paper, the history of the Salet phenomenon is summarized and various experimental configurations are studied for the measurement of the S2 and HPO emission from different sulfur and phosphorus species in low-temperature flames.
01 Jan 1972
TL;DR: In this article, a small-scale apparatus was used to examine the effects of surface materials on the initiation of waves on water by the action of wind, and the effect of various forms of subsequent contamination were investigated, using a sensitive moire fringe wave slope observation technique.
Abstract: A small-scale apparatus was used to examine the effects of surface materials on the initiation of waves on water by the action of wind. Rigorous procedures were followed to ensure freedom from contamination of the initial water surface, and the effect of various forms of subsequent contamination were investigated, using a sensitive moire fringe wave slope observation technique. Provision was made in the design of the water container for insoluble films to circulate, avoiding the downwind buildup of contamination.In measurements on pure water surfaces, no evidence of a ‘critical wind velocity’ was found, although slightly contaminated water was found to be appreciably less responsive to the wind excitation at wind speeds up to 4 m s−l. Measurements on monolayer-covered surfaces showed that, at these wind speeds, a compressed monolayer of relatively high surface tension and low dilational elasticity can have a greater stilling effect than one of low surface tension and high dilational elasticity. Measurements on a series of solutions of surface-active material, covering a range of surface tensions from 63 to 26 mN m−l at a concentration expected to reduce dilational elasticity by bulk-to-surface diffusion, indicated that the damping effect becomes steadily greater as the surface tension decreases.
TL;DR: In this article, the effects of chemical dispersants on the microbial decomposition of crude oil in aquatic environments were evaluated using the Warburg technique for following oxygen uptake and the results showed that the rate of biological destruction of hydrocarbon can be increased using a suitable chemical agent, and that this rate can be further increased by seeding the emulsion with microorganisms capable of utilizing hydrocarbons as food source.
Abstract: Tests were made to determine the effects of chemical dispersants on the microbial decomposition of crude oil in aquatic environments. The Warburg technique for following oxygen uptake was used. Both fresh and sea water condition's were studied and compared to a sample of oil and water with no chemicals added. An oil-water ratio of 1:200 was used, as was a one percent solution of chemical in oil as an emulsion. Six surfactants were used in the tests, and the emulsion was used both alone and in conjunction with an injection of a microbial culture. The results showed that the rate of biological destruction of hydrocarbon can be increased using a suitable chemical agent, and that this rate can be further increased by seeding the emulsion with microorganisms capable of utilizing hydrocarbons as food source. These results can be applied both to cases of oil pollution and for industrial waste water treatment.
TL;DR: In this paper, the problem of post-tensioning the cables of a cable-stayed bridge is approached from the point of view of reducing bending moments and displacements.
Abstract: The cable stayed bridge is a structure well suited for load balancing, that is for reduction of bending moments and displacements throughout the structure by post-tensioning the cables The problem was approached frist from the point of view of reducing bending moments A procedure was developed to achieve this reduction The first step of this method consists of determining the bending moments due to a unit force applied successively along each cable of the bridge system Next, a system of equations is written to express the condition that the sum of the bending moments due to unknown post-tensioning forces in the cables, shall be opposite in sign and equal to a fraction of the bending moment caused by the action of the dead load By solving this system of equations, the post-tensioning forces in cables are determined A computer program was written in FORTRAN language to carry out the computations