Showing papers by "Worcester Polytechnic Institute published in 1975"
TL;DR: The relaxation response is a simple, no cost, non-pharmacological mechanism without side-effects which seemed to decrease the frequency of P.V.C.C.'s in most patients with ischaemic heart-disease.
108 citations
TL;DR: In this paper, a general unsteady state analysis is employed to derive a mathematical model of a freeze-drying process using microwave heating, which takes into account the variations of the transport and dielectric properties in the sample with both time and location as a function of temperature and pressure.
Abstract: A general unsteady state analysis is employed to derive a mathematical model of a freeze-drying process using microwave heating. The model takes into account the variations of the transport and dielectric properties in the sample with both time and location as a function of temperature and pressure. The variations of the properties are described by functionals which have been derived from literature data and are built into the model.
The mathematical model is used to simulate the freeze drying of beef meat with microwave energy at 2450 MHz. The simulation shows that drying rates are essentially a function of the microwave power input. The model also shows that the total pressure and the partial pressure of water vapor in the vacuum chamber directly affect the sample temperature during dehydration. The simulation shows, in particular, that, an optimal microwave freeze-drying operation corresponds to an operation near corona and overheating/melting conditions.
70 citations
TL;DR: Experimental drying curves have been obtained for the freeze-dehydration of beef meat with microwave energy at 2450 MHz, and experiments conducted with slabs of raw beef meat approximately 1.5 cm thick show that total drying times of less than 6 hr can be obtained as mentioned in this paper.
Abstract: Experimental drying curves have been obtained for the freeze-dehydration of beef meat with microwave energy at 2450 MHz. In particular, experiments conducted with slabs of raw beef meat approximately 1.5 cm thick show that total drying times of less than 6 hr. can be obtained. Further drying time reductions are possible if microwave heating and freezing techniques are improved. Samples can be dried slightly faster at a higher pressure (for example, 1 mmHg) than at a lower pressure (for example, 0.2 mmHg) for the same microwave power input. However, melt back and vaporization occur if the pressure or the microwave power input is too high.
Comparison of the experimental drying curves with those predicted by the theory shows a reasonable agreement which, at least in part, verifies the validity of the previously derived mathematical model.
40 citations
TL;DR: In this article, the kinetics of the monolith-and particulate-supported enzymes were analyzed in a continuous tubular reactor system and pressure drop was also monitored, and it was shown that the monolithic-supported system presents very little resistance to flow which results in a considerably smaller pressure drop than is obtained in flow through particulate supported systems under comparable conversion conditions.
Abstract: Catalase was immobilized on commercially available monolithic catalyst supports and also on participate support obtained by crushing the monolith. The kinetics of the monolith- and particulate-supported enzymes were analyzed in a continuous tubular reactor system and pressure drop was also monitored. Analysis of the results indicates that the monolith-supported system presents very little resistance to flow which results in a considerably smaller pressure drop than is obtained in flow through particulate-supported systems under comparable conversion conditions. Ceramic monoliths thus appear to be very suitable for use as enzyme supports in continuous tubular reactor applications, particularly where high pressure drops might be expected.
21 citations
TL;DR: In this paper, the effects of dense optical systems on the static and dynamic properties of laser light were investigated and it was shown that, in the presence of multiple scattering, the relaxation time may be significantly smaller than that predicted on the basis of the single-particle Brownian model.
Abstract: We report on the effects of dense optical systems on the static and dynamic properties of laser light. The measurements of the angular irradiance distribution as a function of the optical density and the size of the scattering centers confirm previous measurements performed by Woodward. Our study of the scattered irradiance correlation function indicates that, in the presence of multiple scattering, the relaxation time may be significantly smaller than that predicted on the basis of the single-particle Brownian model. Furthermore, the angular dependence of the irradiance relaxation time deviates from the usual proportionality to the inverse square of the momentum transfer. We discuss a number of tests that have been performed to minimize the possibility that some of our conclusions could be affected in part by particle aggregation, surface charges, and depolarization of the scattered light.
17 citations
TL;DR: In this article, a perturbative approach was used to analyze the diffusion equation for the atomic quasiprobability function derived by Narducci, Coulter, and Bowden, and it was shown explicitly that the first-order correction contributes to the atomic moments only to order the cooperation number.
Abstract: We use a perturbative approach to analyze the diffusion equation for the atomic quasiprobability function derived by Narducci, Coulter, and Bowden, and demonstrate explicitly that the first-order correction contributes to the atomic moments only to order $\frac{1}{N}$, where $N$ is proportional to the cooperation number.
11 citations
TL;DR: In this paper, a flat plate of sandwich type construction was instrumented with small pressure transducers with outputs that were processed and recorded on an oscillographic recorder, and the results were presented as instantaneous differential pressure distributions for associated wave positions, sequentially as the wave progresses.
Abstract: In the analysis, the plate is imagined to be rigidly suspended at an arbitrary fixed depth and then replaced by a vortex sheet the strength of which varies both temporarily and spatially. The velocity potential of this sheet is adjusted such that, when combined with the potential of the oncoming waves, boundary conditions on the plate, the free surface, and the bottom are approximately satisfied. The final vortex strength distribution can be determined allowing the velocity field and thus the pressure distribution on each side of the plate to be calculated. The experimental program was conducted using a 4x4x40ft (1.2x1.2x12-m) flume with a generator capable of producing waves having a broad frequency and amplitude spectrum in varying water depths. A flat plate of sandwich type construction was instrumented with small pressure transducers with outputs that were processed and recorded on an oscillographic recorder. Results are presented as instantaneous differential pressure distributions for associated wave positions, sequentially as the wave progresses. An advantage of the analytic approach is that pressure distributions as well as total forces may be readily obtained.
11 citations
8 citations
TL;DR: The organization and operation of the internship program are presented, and the essential features leading to its success are analyzed.
Abstract: This paper describes the development of an internship program between St. Vincent Hospital (SVH), a large community teaching hospital, and Worcester Polytechnic Institute (WPI), a school of engineering. The primary objective of the internship program is the education of the student through problem solving in the hospital environment under close faculty-physician supervision. WPI receives an expanded educational base, and SVH receives a diversified base of technical assistance. During the last three years of operation 70 students, 12 faculty, and 15 hospital project advisors have worked together on 29 different student projects. The organization and operation of the internship program are presented, and the essential features leading to its success are analyzed.
7 citations
TL;DR: The results showed that each color has a distinct instantaneous phase deviation, which suggests that subjective color information is transmitted in the visual pathway via an angle modulated system, and statistical communication techniques can be effectively used to suggest a possible explanation for the perception of subjective color.
7 citations
TL;DR: In this paper, an interior solution to plane-symmetric Einstein-Maxwell equations is given for zero pressure for the general case, assuming a functional relationship between the coefficients of the metric and the solution can be written in an integral form.
Abstract: For zero pressure we obtain an interior solution to plane-symmetric Einstein-Maxwell equations. For the general case we assume a functional relationship between the coefficients of the metric and show that the solution can be written in an integral form.
01 Dec 1975
TL;DR: A suggested minor program in Computer Science is presented with a review of experiences and a specific number of thematically related courses in the minor discipline.
Abstract: There has been a great demand for scientists and engineers to become thoroughly acquainted with the application of digital computers to their discipline areas. As a result, engineering and science majors have been interested in complimenting their programs with a minor in Computer Science. Traditionally, minor programs required a specific number of thematically related courses in the minor discipline. However, this traditional approach does not necessarily fulfill the real demands of the students involved in Computer Science. A suggested minor program is presented with a review of experiences.
01 Jan 1975
TL;DR: In this paper, the authors use the r-mode direct product coherent states as generating functions for r-level coherent states which are ideal for the description of collective behavior of an ensemble of N identical rlevel atoms or molecules, where the r levels are not necessarily evenly spaced.
Abstract: We use the r-mode direct product coherent states as generating functions for r-level coherent states which are ideal for the description of collective behavior of an ensemble of N identical r-level atoms or molecules, where the r-levels are not necessarily evenly spaced. It is noted that the Lie algebra for an r-level system can be given a realization in terms of bilinear combinations of boson creation and annihilation operators. This provides a homomorphism from the algebra describing a multimode system to the algebra describing a multilevel system. This in turn provides a homomorphism from the multimode coherent states and their diagonal projectors onto the multilevel coherent states and their diagonal projectors. The action of a creation or annihilation operator on a multimode projector can be replaced by the action of a first order differential operator.
TL;DR: In this paper, the phase-coexistence curve of a binary mixture of phenol and water in the vicinity of the critical mixing temperature was measured and the critical exponent β of the order parameter was calculated.
31 Dec 1975
TL;DR: In this paper, it was shown that the autocatalytic nature of the base catalyzed condensation of formaldehyde to formose sugars is eliminated by using as a cocatalyst, an aldose, or ketose having an alpha-hydrogen.
Abstract: The autocatalytic nature of the base catalyzed condensation of formaldehyde to formose sugars is eliminated by using as a cocatalyst, an aldose, or ketose having an alpha-hydrogen. This is more strongly complexed by base than is formaldehyde and the cocatalyst and sugar products accumulate as catalyst complexes instead of formaldehyde. Because of the presence of alpha-hydrogen atoms in cocatalysts and formose sugars, their removal by cross Cannizzaro reaction of complexed sugars does not occur, so the formose reaction behaves autocatalytically due to this accumulation. It is believed that a given catalytic formose complex is not a discrete complexed sugar, but rather, a scrambled dynamic mixture of sugars having weakened structures. The sugar complexes derive from a common salt-like formaldehyde complex, which, because of the absence of alpha-hydrogen, has a greater tendency to undergo Cannizzaro reaction, rather than formose condensation. Because of this, the Cannizzaro reaction can proceed without measurable formose condensation. The reverse is not possible.
TL;DR: In this paper, the average effect on the estimator of Kendall's rank correlation coefficient when extreme pairs are removed from a sample was derived. Butts and Hinton derived the exact bias, and an approximation, for n = 3(1) 19.
Abstract: This article obtains the average effect on the estimator of Kendall's rank correlation coefficient when extreme pairs are removed from a sample. Formulas, which are functions of Sterling numbers of the second kind, are derived for this bias. The exact bias, and an approximation, are tabulated for n = 3(1) 19.