Showing papers by "Stevens Institute of Technology published in 1987"
Patent•
11 May 1987TL;DR: In this paper, a teacher station 4 and a plurality of student stations 6 which may be located at sites remote from one another are connected to a speaker telephone 122, 122' or other voice telephone set which is connectable to a telephone system 124 for voice communication among the various stations.
Abstract: A remote teaching system 2 includes a teacher station 4 and a plurality of student stations 6 which may be located at sites remote from one another. Each station 4, 6 includes a speaker telephone 122, 122' or other voice telephone set which is connectable to a telephone system 124 for voice communication among the various stations. Each station 4, 6 includes a video display monitor 14, 14' such as a television set and a video media player 16, 16' such as a video-tape cassette player connected to the video display monitor 14, 14'. Each student station 6 also includes a video-media-player controller 8', 22' which is connected to the video media player 16' of the student station 6 for controlling the playing of the player. The teacher station 4 includes a video-media-player master controller 8, 22 connected to the video media player 16 of the teacher station 4 for controlling the playing of the player. The video-media-player master controller 8, 22 of the teacher station 4 and the video-media-player controller 8', 22' of the student stations are connectable to the telephone system 124 for transmitting and receiving telephonic control signals over the telephone system, so that the playing of the video media player 16 of the teacher station 4 and the video media players 16' of the student stations 6 can be synchronized.
145 citations
TL;DR: In this paper, the distribution of error eigenvalues resulting from principal component analysis is deduced by considering the decomposition of an error matrix in which the errors are uniformly distributed.
Abstract: The distribution of error eigenvalues resulting from principal component analysis is deduced by considering the decomposition of an error matrix in which the errors are uniformly distributed. The derived probability function is
Where λ0j is the jth error eigenvalue, r and c are the numbers of rows and columns in the data matrix, and N is the normalization constant. This expression is tested and validated by investigations involving model data. The distribution function is used to determine the number of factors responsible for various sets of spectroscopic data taken from the chemical literature (including nuclear magnetic resonance, infrared and mass spectra).
129 citations
TL;DR: In this article, a coupled cluster and manybody perturbation theory methods that include triple excitation effects were applied to the determination of the quartic force field of the water molecule using an extended Slater-type basis set.
Abstract: Ab initio coupled cluster and many‐body perturbation theory methods that include triple excitation effects are applied to the determination of the quartic force field of the water molecule using an extended Slater‐type basis set. Predictions of fundamental, overtone, and combination vibrational frequencies, rotational constants, and vibration–rotation coupling constants are reported for H2O and its isotopomers. The best predicted harmonic frequencies for the stretching modes of H2O are accurate to 3 cm−1, while the bending mode has an error of 28 cm−1. The mean absolute error for all frequencies reached by two quanta is 0.6%, while the anharmonic constants xi j have a mean absolute error of less than 3%. The important role of triple excitation effects in the surface determination is discussed, and is compared with the effects of quadruple excitations.
81 citations
TL;DR: In this article, the applicability and limitations of such a model for a number of membrane-solute-solvent systems were studied and the boundary layer and membrane resistances to solute transport were isolated and simple relations developed for the overall mass transfer coefficient in such systems.
Abstract: Dispersion-free solvent extraction using microporous hydrophobic membranes has been extended to hydrophilic and composite hydrophobic-hydrophilic membranes. Excess phase pressure conditions, if needed for dispersion-free operation, have been identified. Boundary layer and membrane resistances to solute transport have been isolated and simple relations developed for the overall mass transfer coefficient in such systems. A variety of flat microporous membranes have been utilized. Previous investigations by others had interpreted the membrane mass transfer resistance using the notion of unhindered diffusion through tortuous pores of the membrane. We have studied here the applicability and limitations of such a model for a number of membrane-solute-solvent systems.
76 citations
TL;DR: In this paper, the authors proposed a four load method to evaluate the acoustical source impedance in a duct, where the sound pressure level data measured downstream for four different length ducts, as acoustic loads, is used.
62 citations
TL;DR: The energy loss of a fast-charged-particle probe of a two-dimensional (2D) collisionless solid-state plasma is determined as a function of the distance of the fast particle from the 2D plasma plane, and its velocity.
Abstract: This paper presents an analysis of the energy loss of a fast-charged-particle probe of a two-dimensional (2D) collisionless solid-state plasma. The fast-particle motion is taken to be parallel to the 2D plasma sheet, and the plasma is taken to be in a degenerate state (zero temperature). The 2D plasma response dynamics are described in the random-phase approximation (RPA), and our calculation is a 2D analogue of the well-known Nozi\`eres-Pines energy-loss calculation, but with the particle's trajectory at a fixed distance H from the plane of the 2D plasma sheet. Our calculation includes a determination of the part of the fast particle's energy loss which can be ascribed to the excitation of electron-hole pairs in the 2D plasma, as well as the part which can be ascribed to 2D plasmons (of all wave numbers). We determine the energy loss as a function of the distance of the fast particle from the 2D plasma plane, and its velocity.
46 citations
Book•
01 Jan 198746 citations
TL;DR: In this article, a hollow-fiber permeator that simultaneously houses two different types of membranes, cellulose acetate and silicone rubber, was investigated, and the two membranes have reverse selectivities with respect to He and CO2.
Abstract: Single-stage separation of ternary gas mixtures of He, CO2, and N2 in a hollow-fiber permeator that simultaneously houses two different types of membranes, cellulose acetate and silicone rubber, was investigated. The two membranes have reverse selectivities with respect to He and CO2. Such a two-membrane permeator separates the feed into three streams, two permeates and one reject, each stream being enriched in a different component. The species permeabilities through each membrane were measured independently, and these values were utilized in a simulation that incorporates the fiber lumen pressure drops, the elastic deformation of the silicone capillaries, and the asymmetric structure of the CA membrane. Simulation results are compared with experimental data. Effects of flow pattern, relative permeation areas of the two membranes, permeate pressure ratios, feed composition, and membrane selectivities are studied. Advantages of the two-membrane scheme over the conventional permeators with only one kind of membrane are discussed.
44 citations
TL;DR: In this article, a new method of studying slurry packing in liquid chromatography microcolumns is described, which employs several physico-chemical parameters including colloid physics, slurry rheology and filtration.
33 citations
TL;DR: In this article, the authors evaluated the effect of intelligence on overall accuracy, differential elevation, stereotype accuracy, and differential accuracy on a set of three sets of videotapes which presented simulated work performances by five ratees.
33 citations
TL;DR: In this paper, the valence, Rydberg, and ion pair characteristics of 1Σ+u states of N2 were studied in ab initio calculations involving selectively optimized basis sets of Slater-type functions and configuration mixing.
Abstract: The valence, Rydberg, and ion pair characteristics of 1Σ+u states of N2 are studied in ab initio calculations involving selectively optimized basis sets of Slater‐type functions and configuration mixing. Potential energy curves, as well as transition dipole moments and second moments of charge as a function of internuclear separation, are reported for 1Σ+g and 1Σ+u states. Transition dipole moments are in good agreement with experiment as are spectroscopic constants for the observed states. Analysis of the second moment and transition moment functions for the lowest 1Σ+u state shows clearly a transformation from atom pair to valence to ion pair to nearly pure Rydberg character as a function of internuclear separation between the separated atoms and the united atom limits.
TL;DR: In this paper, all regular geometric configurations of beryllium clusters containing three through seven atoms were investigated using restricted Hartree-Fock, unrestricted Hartree Fock, and fourth-order Mo/ller-Plesset perturbation theory.
Abstract: Ab initio calculations were carried out on all regular geometric configurations of beryllium clusters containing three through seven atoms. Restricted Hartree–Fock, unrestricted Hartree–Fock, and fourth‐order Mo/ller–Plesset perturbation theory (MP4) using a 6‐31G basis set were used to study singlet, triplet, and quintet spin states of each cluster. The septet state of the most stable nuclear configuration of Be7 was also examined using unrestricted Hartree–Fock theory. In addition, Be4 was examined as a prototype for larger clusters, for which accurate calculations may not be computationally feasible. The most stable symmetric nuclear configuration and electronic state of Be4 was determined at increasingly improved levels of approximation. Hartree–Fock, configuration interaction, and Mo/ller–Plesset perturbation theory calculations were carried out using 6‐31G, 6‐311G, 6‐31G*, and 6‐311G* basis sets. Binding energies for the most stable configuration of each cluster were improved by MP4 calculations in ...
TL;DR: In this paper, the authors derived the following simple formula for t(Pn ) the number of spanning trees in the prism Pn, defined as the graph obtained by adding to the disjoint cycles all edges of the form ViWi The prism is sometimes denoted by K 2×Cn.
Abstract: Let the vertices of two disjoint, equal length cycles be labelled in one cycle and in the other. The prism Pn is defined as the graph obtained by adding to the disjoint cycles all edges of the form ViWi The prism is sometimes denoted by K 2×Cn . In this work we derive the following simple formula for t(Pn ) the number of spanning trees in .
TL;DR: Commercially available tris(3,6-dioxaheptyl)amine (TDA-1) is an effective phase transfer catalyst for reactions with sodium-potassium alloy in tetrahydrofuran as mentioned in this paper.
TL;DR: In this paper, a systematic experimental study was conducted on the elementary process of devolatilization (DV) of volatile contaminants from polymer melts, focusing on foam-enhanced DV from rolling melt pools, which are present in rotating machinery.
Abstract: A systematic, experimental study was conducted on the elementary process of devolatilization (DV) of volatile contaminants from polymer melts. Emphasis was placed on foam-enhanced DV from rolling melt pools, which are present in rotating machinery. All experiments were conducted in a specially designed apparatus at room temperature using poly(dimethyl siloxane) to simulate the melt, and methyl chloride together with several chlorofluorocarbons as the contaminants. The special apparatus was devoid of the flow complexities present in industrial equipment and permitted independent control of all pertinent operating parameters. Physical properties and process parameters examined include feed composition and vapor pressure of contaminant, applied vacuum level, rotational speed of the pool, viscosity of the melt, and the effect of air entrainment.
TL;DR: In this paper, the radiation reaction force and balance equations are derived for slow-motion, gravitationally bound systems with compact components such as neutron stars and black holes using the EIH procedure.
Abstract: The radiation reaction force and balance equations are derived for slow-motion, gravitationally bound systems with compact components such as neutron stars and black holes. To obtain these results, use is made of the Einstein-Infeld-Hoffmann (EIH) procedure. As a consequence, all quantities involved in the derivation are finite and hence no renormalization is required. Furthermore, no laws of motion for the components need be assumed. Approximate expressions for the fields required to evaluate the EIH surface integrals are obtained using the methods of matched asymptotic expansions and multiple time scales. The results obtained are the same as those derived previously for systems with noncompact components.
TL;DR: In this article, self-consistent field calculations using effective core potentials are reported for electronic states of Be 51 and Be 57 clusters, which correspond to the seventh and eighth coordination spheres of a central Be with internuclear separations derived from the lattice constants of the bulk metal.
TL;DR: In this article, the thermal-noise temperature for hot electrons in steady-state transport in the presence of a strong dc electric field with a finite phonon relaxation time is examined with use of a nonlinear-balance-equation theory.
Abstract: The thermal-noise temperature for hot electrons in steady-state transport in the presence of a strong dc electric field is examined with use of a nonlinear-balance-equation theory with a finite phonon relaxation time. In defining the noise temperature in terms of the maximum available noise power, we find that it is necessary to distinguish between the ``noise'' conductivity and the signal conductivity for nonzero dc bias. Particular attention is focused on single-layer and multilayer GaAs heterosystems. The longitudinal and transverse noise temperatures are calculated as functions of frequency at different dc bias points taking into account the impurity, acoustic-phonon, and polar optic-phonon scatterings, as well as the Coulomb interaction between carriers in the random-phase approximation. For three high-mobility (1\ifmmode\times\else\texttimes\fi{}${10}^{6}$ ${\mathrm{cm}}^{2}$/V s) GaAs heterosystems, both longitudinal and transverse noise temperatures are shown to be lower than the lattice temperature T (77 K) for wide ranges of dc electric field and frequency in the case of zero phonon relaxation time. However, the nonequilibrium population of the polar optic phonon generally suppresses the effect of electron cooling.
TL;DR: In this paper, the authors measured the dependence of the work function on Cs coverage of clean polycrystalline Be and showed that the minimum work function surface is at 1.6 eV.
TL;DR: A simulation of an NMR redundant processor system was constructed using a gate level simulation package and the ability of each digital processor to react to randomly induced stuck-at faults was measured.
Abstract: Latent faults represent a potential obstacle in the synthesis of highly reliable digital computer systems. A simulation of an NMR redundant processor system was constructed using a gate level simulation package. The ability of each digital processor to react to randomly induced stuck-at faults is measured, and the amount of time it took the processor's control program to propagate faults to an output was recorded. These propagation times represent the latency times of the faults. The effect of fault latency in degrading system reliability is explored.
TL;DR: In this article, the authors describe how the model for assessment center design that is widely used today came to be accepted as a standard, and then modifications in design and operation are discussed.
Abstract: Empirical research has consistently supported the validity and business utility of the assessment center method as a selection instrument. Nonetheless, the method as typically applied may be unnecessarily costly and inflexible. This paper begins by describing how the model for assessment center design that is widely used today came to be accepted as a standard. Then modifications in design and operation are discussed. These suggested modifications are intended to enhance the utility and flexibility of assessment centers, while at the same time maintaining, or even increasing, the validity of the process.
TL;DR: A numerical study of the secondary flows which occur in the laminar pressure-driven motion of dilute polymer solutions in ducts of rectangular cross-section is presented in this paper.
Abstract: A numerical study of the secondary flows which occur in the laminar pressure-driven motion of dilute polymer solutions in ducts of rectangular cross-section is presented The full nonlinear equations of motion for a Maxwell fluid with shear thinning are solved by an explicit finite-difference technique Results are presented in an inertial framing which indicate the existence of the previously observed eight-vortex secondary flow in ducts of various aspect ratios In addition, the effect of spanwise rotations on the strength and the structure of the secondary flow is examined The results indicate that even the mere presence of the diurnal rotation of the earth can give rise to a double-vortex secondary flow which is of a comparable order of magnitude to the viscoelastic secondary flows in dilute polymer solutions Specific computations are presented which illustrate the distortional effect that the imposition of a spanwise rotation has on the viscoelastic secondary flow structure in square ducts The implications that these results can have on laboratory experiments are discussed briefly along with other possible applications to rotating and curved flows
TL;DR: In this article, the yield and tensile strengths of nickel electrodeposits were increased by a factor of three by the periodic imposition of an anodic current pulse, and the time periods between pulses were much longer than those used in periodic reversal plating.
Abstract: The yield and tensile strengths of nickel electrodeposits were increased by a factor of three by the periodic imposition of an anodic current pulse. The time periods between pulses were much longer than those used in periodic reversal plating. The increased strength was attributed to grain refinement resulting from nucleation on surfaces which became passivated during the anodic pulses. The reduced adhesion between layers plated between pulses resulted in a reduction in the coefficients of friction.
TL;DR: Optimisation de la conception de mecanismes plans flexibles integrant la cinematique et la dynamique as mentioned in this paper, a.k.a. flexibility.
Abstract: Optimisation de la conception de mecanismes plans flexibles integrant la cinematique et la dynamique
TL;DR: The work in this paper was stimulated by important connections between the chromatic polynomial and the all-terminal network reliability problem, and by recent work of Boesch, Satyanarayana, and Suffel on a graph invariant related to the K -terminal reliability problem.