Showing papers by "University of Houston published in 1968"
TL;DR: In this article, a model simplification approach for high-order transfer functions is presented. But it does not cover the general analysis of linear systems and is not suitable for general linear systems.
Abstract: New techniques for the model simplification problem are presented. If the given system is expressed by a high-order transfer function, the technique is to expand the function into a continued fraction and then ignore some quotients. If the system is in the state equations form, the method is realized by partitioning the matrix and discarding some parts. The new approach not only offers a simple procedure and a good approximation but also gives a unified viewpoint of the general analysis of linear systems.
273 citations
TL;DR: The hydrocarbon composition of two algae, a golden-brown (Bot-ryococcus braunii) and a blue-green (Anacystis montana), has been investigated by gas chromatography-mass spectrometry and may be the precursors of the hydrocarbons in these formations.
Abstract: The hydrocarbon composition of two algae, a golden-brown (Bot-ryococcus braunii) and a blue-green (Anacystis montana), has been investigated by gas chromatography-mass spectrometry. Both show distributions of aliphatic hydrocarbons of odd carbon numbers in the medium and high ranges of molecular weight, with maxima at n-C17 and n-C29 for B. braunii and n-C17 and n-C29 for A. montana. With the exception of the n-heptadecane of A. montana all the hydrocarbons are monoenes, dienes, or trienes. Since certain continental sediments and oils show similar distributions of alkanes with respect to carbon number, these organisms may be the precursors of the hydrocarbons in these formations.
119 citations
TL;DR: The fact is that current procedures for the construction of achievement tests do not provide an unambiguous basis for generalization to a well defined universe of content.
Abstract: IN the measurement of achievement we are seldom exclusively interested in performance on just those items that are actually administered on a test. We almost always have some larger universe of content in mind, and our implicit objective is to generalize over the entire content domain. Few measurement specialists would quarrel with the premise that the fundamental objective of achievement testing is generalization. Yet the fact is that current procedures for the construction of achievement tests do not provide an unambiguous basis for generalization to a well defined universe of content. At worst, achievement tests consist of arbitrary collections of items thrown together in a haphazard manner. At best, such tests consist of items judged by subject matter experts to be relevant to and representative of
82 citations
TL;DR: In this article, a simple and quantitatively accurate representation of the current distribution in a dipole antenna is derived, and numerical data are given and are found to be in good agreement with the experiment when h \geq O.15\lambda.
Abstract: A simple and quantitatively accurate representation of the current distribution in a dipole antenna is derived. Numerical data are given and are found to be in good agreement with the experiment when h \geq O.15\lambda .
73 citations
72 citations
48 citations
TL;DR: In this article, it is shown that for macro-cracks when the crack radius l is not too small, the following formula holds for quasi-brittle solids, which agrees with the Orowan-Irwin modification of Griffith's theory; (dWp/dA)crit denotes the plastic work per unit area of new surface, dissipated in the course of loading before fracture.
Abstract: A penny-shaped crack in a material which is ideally elastic-plastic has been envisaged with the assumption that the plastic zone forms a very thin layer surrounding the crack. The Dugdale hypothesis has been adapted and thus the problem has been reduced to that of an elastic semi-space with properly modified boundary conditions. The entire energy absorbed in the process of creation of a new surface is associated with the work expanded in irreversible plastic deformation, the work of cohesive forces being neglected. The displacements of the crack surfaces are calculated as well as the plastic energy dissipation and the fracture criterion is discussed. The shape of the crack, obtained here, differs considerably from that predicted by the theory of elasticity, particularly at the crack tip. The differences in the values of the critical pressure calculated from the Griffith-Sack-Sneddon formula and those obtained by use of the equations derived here are also significant. It is shown that for macro-cracks when crack radius l is not too small the following formula holds
$$P_{crit} = [\pi E\left( {dW_p /dA} \right)_{crit} /2\left( {1 - v^2 } \right)]^{{\raise0.5ex\hbox{$\scriptstyle 1$}\kern-0.1em/\kern-0.15em\lower0.25ex\hbox{$\scriptstyle 2$}}} $$
which agrees with the Orowan-Irwin modification of Griffith's theory; (dWp/dA)crit denotes the plastic work per unit area of new surface, dissipated in the course of loading before fracture. The results of this paper hold for the so called ‘quasi-brittle’ solids. Two schemes of loading are considered: 1. pressure applied on the crack surfaces and 2. applied at infinity. Attention is paid to a slightly different mechanism of fracture in both the cases.
38 citations
TL;DR: In this paper, the kinetics of formation and dissociation of one-to-one lanthanide oxalate complexes by a pressure jump technique were determined as a function of temperature and activation parameters calculated.
38 citations
TL;DR: In this paper, a model simplification approach for high-order transfer functions is presented. But it does not cover the general analysis of linear systems and is not suitable for general linear systems.
Abstract: New techniques for the model simplification problem are presented. If the given system is expressed by a high-order transfer function, the technique is to expand the function into a continued fraction and then ignore some quotients. If the system is in the state equations form, the method is realized by partitioning the matrix and discarding some parts. The new approach not only offers a simple procedure and a good approximation but also gives a unified viewpoint of the general analysis of linear systems.
37 citations
TL;DR: In this paper, a new technique of obtaining sufficient conditions for uniqueness of the steady state solution in distributed parameter systems is presented, which is applied for the cases of an adiabatic or isothermal reaction in a porous catalyst.
36 citations
TL;DR: Microcrystalline cellulose was exposed to the atmosphere of the tableting room and it was found that this exposed material did not tablet as well as material taken from the original, sealed container.
TL;DR: In this paper, a mehtod is presented for determining finite stability regions for distributed parameter systems whose transient behavior is governed by a single parabolic differential equation, which can be applied to many other systems in which chemical reactions and diffusions are coupled.
TL;DR: The wax fraction from chlamdospores of Ustilago maydis (Basidiomycetes) were analyzed by gas chromatography and mass spectrometry combination.
TL;DR: Preliminary results lend support to the effectiveness and utility of this procedure in assessing behavioral change within a natural setting.
Abstract: The purpose of the present investigation was to develop a behavioral measure of attitude change and examine its utility for large-scale field research efforts. Three groups were formed from 68 junior and senior high school students and each was presented with a different form (positive, fear, neutral) of a communication within the context of a public school system's ongoing dental hygiene program. Cleanliness of their teeth was measured by a chemical in tablet form called a “disclosing tablet” which, when chewed, stains red the areas of concentration of bacterial placque on the teeth. This study involved taking a 35-mm. color slide of each S's mouth before and 2 wk. after the experimental communication. Preliminary results lend support to the effectiveness and utility of this procedure in assessing behavioral change within a natural setting.
TL;DR: Discriminative control of lever choice and response patterning by internal states was demonstrated in rats trained on a two lever mult FR DRL schedule of food reinforcement.
Abstract: Discriminative control of lever choice and response patterning by internal states was demonstrated in rats trained on a two lever mult FR DRL schedule of food reinforcement. Saline was administered on days when the FR component was programmed and amphetamine when DRL was in effect. On subsequent extinction sessions, the animals responded on the lever and at rates which were appropriate to the compound administered.
TL;DR: A number of studies investigating the relationship between absenteeism and grades have produced conflicting results as mentioned in this paper, however, a number of investigators have found that there is a definite relationship between absentness and grades.
Abstract: PREVIOUS studies investigating the relationship between absenteeism and grades have produced conflicting results. A number of investigators have found a definite relationship between absenteeism and grades. Sandon (1938) examined academic marks of 406 male secondary students in the term following recorded absences. He found that the quality of work was definitely affected by the number of absences during the previous term. Significant relationships among absences and grades recorded within the
TL;DR: It is very important to develop a theoretical understanding of the nature of the excited states and their change as a function of the angle of twist around the 11–12 bond of the cis isomer.
Abstract: ALL-trans and 11-cis retinals play important parts in the visual process because of the existence of the 11-cis polyene in rhodopsin. Spectroscopic studies of these show that there is weak emission from all-trans retinal and very little from the 11-cis isomer1. Also, rhodopsin shows only a very weak emission2. It is very important to develop a theoretical understanding of these results as well as of the nature of the excited states and their change as a function of the angle of twist around the 11–12 bond of the cis isomer.
TL;DR: The major components of the lipid fraction of the leaves of cabbage have been identified by means of gas Chromatography and combined gas chromatography-mass spectrometry as mentioned in this paper, and the major components being linolenic, linoleic, and palmitic, which together constituted more than 50 per cent of the total fatty acids present.
TL;DR: Pontocypria helenae sp.
Abstract: [Pontocypria helenae sp. n. (Pontocyprididae, Ostracoda), est le premier Podocopide marin commensal et le premier Cypridaceen commensal. Elle se sert du croc terminal characteristique de l'antenne pour s'accrocher a la base des bras de trois especes d'etoiles de mer (Astropectinidae, Asteroidea) antarctiques. Pontocypria humesi sp. n., est signalee comme vivant libre sur une eponge a Nosy Be, Madagascar. Aglaia (?) meridionalis Brady 1880, doit etre rattachee a Pontocypria comme combinaison nouvelle. L'ontogenie et l'homologie du croc et des soies de l'antenne sont decrites et comparees avec celles de Propontocypris., Pontocypria helenae sp. n. (Pontocyprididae, Ostracoda), est le premier Podocopide marin commensal et le premier Cypridaceen commensal. Elle se sert du croc terminal characteristique de l'antenne pour s'accrocher a la base des bras de trois especes d'etoiles de mer (Astropectinidae, Asteroidea) antarctiques. Pontocypria humesi sp. n., est signalee comme vivant libre sur une eponge a Nosy Be, Madagascar. Aglaia (?) meridionalis Brady 1880, doit etre rattachee a Pontocypria comme combinaison nouvelle. L'ontogenie et l'homologie du croc et des soies de l'antenne sont decrites et comparees avec celles de Propontocypris.]
TL;DR: The liver oil from the South American Basking shark has been fractionated by silica gel chromatography and analyzed by the new method of combined gas-chromatography mass spectrometry, presenting mass spectral data for squalene for the first time along with the low electron energy-mass spectra for pristane and phytane.
Abstract: The liver oil from the South American Basking shark has been fractionated by silica gel chromatography and analyzed by the new method of combined gas-chromatography mass spectrometry. The major compounds of the nonsaponifiable fraction are pristane and squalene, which account for 7.6 and 31.3% of the oil. The saponifiable fraction contains normal fatty acids from C14 to C22; the four major components are palmitic, oleic, and the monounsaturated eicosenoic and docosenoic acids. No correlation was observed between the hydrocarbons (essentially all isoprenoid derivatives) and the fatty acids (essentially all normal) of this oil. The same treatment was applied to a sample of commercial pristane which was obtained from Basking shark liver oil. It was found to contain about 1% phytane and small amounts of octadecane, nonadecane, and methyl and ethyl palmitates. Mass spectral data for squalene are presented for the first time along with the low electron energy-mass spectra for pristane and phytane.
TL;DR: When a flat stimulus is rotated in the frontoparallel plane about a horizontal axis that is an extension of O's line of regard, the apparent depth of the stimulus is enhanced.
Abstract: When a flat stimulus is rotated in the frontoparallel plane about a horizontal axis that is an extension of O's line of regard, the apparent depth of the stimulus is enhanced. The enhancement was entirely a function of peripheral asymmetry. The apparent depth in the static figure, internal structure, or taper in the periphery did not augment the rotation-enhanced depth. The magnitude of the enhancement was constant for any series of stimuli, such as a series of overlapping circles with increasing overlap. The apparent depth also increased as a function of the speed of rotation.
TL;DR: M�ssbauer spectra of several iron meteorites have been measured by a resonant scattering technique rather than by the conventional transmission method, thereby eliminating the necessity for the preparation of thin samples.
Abstract: Mossbauer spectra of several iron meteorites have been measured by a resonant scattering technique rather than by the conventional transmission method, thereby eliminating the necessity for the preparation of thin samples. No significant differences were observed in the spectra of specimens of mechanically deformed, shocked, and unshocked iron meteorites, nor in the absorption spectra of artificially shocked and unshocked fayalite.
01 Nov 1968
TL;DR: In this article, the authors presented an algebraic field pattern analysis for asymmetrically driven long antenna with multiple excitations or loadings, which can be obtained by superposition.
Abstract: The field pattern of an asymmetrically driven long antenna is obtained by the Wiener-Hopf procedure which was used by Wu [1] to calculate the field pattern of a center-fed dipole. The present analysis gives a formula which is algebraic in form and involves no numerical integration. The field pattern of a long antenna with multiple excitations or loadings can be obtained by superposition. The theory is compared with Altshuler's experiment [2] on resistor-loaded traveling-wave antennas and agreement between theory and measurement is found to be good. Application of the present result to field pattern synthesis is possible. For instance, it is known that a traveling wave of current may be produced on a center-driven dipole antenna of finite length when two suitable loads are placed symmetrically at about quarter-wavelength from its ends [2], [3]. A traveling-wave antenna tends to radiate power in an end-fire direction. On the other hand, the field pattern can be made broadside, as is shown in this paper, when the generators and the loads are re-arranged. These facts seems to suggest that a long antenna may be controlled to radiate power in any desired direction by adjusting the values and the positions of its loadings. Due to the simplicity of the formula involved, field patterns can be calculated and plotted or displayed by a computer in a short time as a function of the position of the generator. By inspection and by trial and error, desired field pattern can be obtained when appropriate individual field patterns are superimposed. It may be worthwhile to note that in this procedure the driving voltages and the locations of the generators are found so as to give certain desired pattern, the current distribution on the antenna does not have to be found first. However, the current may be found by using a simple formula derived by Shen, Wu and King [4] after the voltages and locations of the generators have been determined. The proposed method of field pattern synthesis is an alternative to the usual approach in which collinear arrays are used. One of the advantages of the present long antenna theory is that the complicated problem of mutual coupling effects between elements of an array is automatically taken into account. Furthermore, a simple and accurate formula of field pattern of a long antenna is readily available. Besides, a long antenna is a continuous structure and does not have gaps which exist between elements of a collinear array. The absence of such gaps permits coaxial feed lines to run out inside the antenna and thus simplifies the external structure of feeding networks. Two examples are shown in this paper to demonstrate the fact that long antenna can be made to radiate power in broadside direction if appropriate driving voltages are chosen. The result is compared with ideal field patterns of collinear arrays.
TL;DR: In this paper, the authors discuss the relation between the stigma associated with mental illnesses and mental health disorders and the prevalence of mental disorders in the general population, and propose a method to identify the causal factors.
Abstract: (1968). Selected Correlates of the Stigma Associated with Mental Illness. The Journal of Social Psychology: Vol. 74, No. 1, pp. 103-110.
TL;DR: Os judged the apparent sizes of the “near” and “far” faces of a Necker cube and of a “cylinder” percept formed stereokinetically from a pair of overlapping flat circles rotating in the frontal plane to suggest that there is a physiological mechanism for the organization of size-distance relationships.
Abstract: Os judged the apparent sizes of the “near” and “far” faces of a Necker cube and of a “cylinder” percept formed stereokinetically from a pair of overlapping flat circles rotating in the frontal plan...
TL;DR: The estimation of the “subliminal” threshold not only was reliable, but it expands the possibility for clarification of the nature of taste percepts, and the factor scores from these several components of variance may be viewed as new variables that measure these structural pools of variance.
Abstract: Sumnzary.-A rapid ascending method of limits without standards was reliable for determining taste thresholds for NaCl in longirudinal experiments. Three experienced Ss made two judgments-tentative-uncertain and certain (absolure threshold) in each of five series of taste judgments daily for 120 consecutive days. To provide a means of studying functional relationships between taste and other variables, the total variance in all the judgments was partialled into several orthogonal components by means of linear components analysis. Factor scores computed from these components were correlated with a series of values derived direcrly from the judgments. The first component for each S consolidared the variance that arose from the average day-to-day differences in judgments, and the others isolated the variance that was due to within-day linear trends. The relation of the unrotated and rotated components was shown, and the reasons for our preference for the former were explained. The factor scores from these several components of variance may be viewed as new variables rhat measure these structural pools of variance and, as such, they may be correlated with any other pertinent variables such as constiruents of saliva, motivation, environmental temperature, and the like. Furthermore, the estimation of the "subliminal" threshold not only was reliable, but it expands the possibility for clarification of the nature of taste percepts.