Showing papers by "Applied Science Private University published in 1987"
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TL;DR: A technique for the measurement of rotational human back movements in three dimensions has been developed and was shown to be feasible from studies of six volunteers who demonstrated consistent patterns of movement which were similar to previously reported patterns of spinal movement measured radiographically.
74 citations
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01 Jul 1987TL;DR: It was found that under physiological loads, particles of acrylic cement which have been embedded in the polyethylene bearing surface caused severe scratching of the stainless steel.
Abstract: The effect of particles of first, acrylic bone cement containing either barium sulphate or zirconium dioxide as X-ray contrast media, and secondly, particles of fresh cortical bone, on a surgical grade stainless steel surface against which polyethylene was rubbing, has been investigated. It was found that under physiological loads, particles of acrylic cement which have been embedded in the polyethylene bearing surface caused severe scratching of the stainless steel. Some scratches were found to have pronounced lips similar to those observed on the femoral heads of explanted Charnley hip prostheses. Cortical bone produced only slight damage to the stainless steel. In the case of the acrylic cements, the abrasive constituent was isolated and found to be clusters of particles of the X-ray contrast medium. Particles of acrylic cement are frequently observed embedded in the wear surfaces of explanated Charnley acetabular cups and these particles have also been found to contain clusters of X-ray contrast mediu...
65 citations
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TL;DR: In this article, the pyroelectric activity in the alternating-layer Langmuir-Blodgett (LB) assemblies has been assessed and correlated with their structures determined using Fourier transform IR (FTIR) spectroscopy.
44 citations
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TL;DR: In this paper, an underexpanded jet issuing from a convergent slot and blowing over a surface of convex streamwise curvature was studied experimentally, and the main techniques used were Schlieren and shadowgraph to show the jet structure, and surface flow visualization which revealed areas of separation and reattachment.
42 citations
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TL;DR: The CODA-3 system was found to be severely limited in this application due to the problem of cross-over conflict between the retro-reflective prisms that results in the loss of data, and the VICON system was finding to be more flexible but data analysis requires an interactive input from the operator and so can be very time consuming.
37 citations
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TL;DR: In this paper, Langmuir-Blodgett films of the 1 : 1 charge transfer salt N -octadecylpyridinium-TCNQ have been deposited onto glass substrates.
32 citations
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TL;DR: In this article, a charge trapping model is presented which predicts a logarithmic increase in the flat band shift with time, based on the simple assumption that there is electron tunnelling between the silicon valence and conduction bands and the deep defect levels in the SRN films.
Abstract: Silicon-rich silicon nitride (SRN) films were grown by low pressure chemical vapour deposition (LPCVD) with excess silicon concentrations varying from 8.8 to 12.8%. All films were found to be predominantly α-Si3N4 with free silicon crystallites being found in the films with the greatest silicon content. MIS capacitors were fabricated from the films and transient flat band measurements were performed on these devices. For positive (negative) applied bias voltages, the flat band shift was in a positive (negative) direction implying a net increase in negative (positive) charge within the SRN film. A logarithmic time dependence was found for the transient flat band shift while for long periods of time (i.e. t > 1 s) the curren transient was found to be inversely proportional to time. A charge trapping model is presented which predicts a logarithmic increase in the flat band shift with time. The model is based on the simple assumption that there is electron tunnelling between the silicon valence and conduction bands and the deep defect levels in the SRN films. Very good agreement was found between the data and the model for low electric fields. At high fields, the situation becomes complicated by other transport processes which lead to a saturation of the flat band shift with time. The current transients are similarily affected. For these SRN films the density of trapping centres near the SRN-silicon interface was found to be of the order of 3 × 1019cm−3.
25 citations
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TL;DR: In this paper, the crystal structure of the Ho-Ba-Cu oxide, which is responsible for high Tc superconductivity, has been investigated by transmission electron microscopy, and it is concluded that the Cu layers expand in the a-b planes even across the twin boundary without any kink.
Abstract: The crystal structure of the Ho-Ba-Cu oxide, which is responsible for high Tc superconductivity, has been investigated by transmission electron microscopy. The lattice belongs to an orthorhombic system with lattice parameters a=3.83 A, b=3.90 A and c=11.8 A. It is an isomorphous structure of the high-Tc superconductor Y-Ba-Cu oxide. Micro twinning of crystal is observed under the high spatial resolution, that is 3 A. The twinned crystals could be observed with incident electron beam parallel to a, b and c-axes of the crystal. It is concluded that the Cu layers expand in the a-b planes even across the twin boundary without any kink.
14 citations
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TL;DR: In this paper, the EPR spectra of Mn/MgO single crystals grown by electrofusion have been examined at 9 GHz for manganese concentration of between 840 and 2900 ppm.
11 citations
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TL;DR: In this paper, the surface pressure fluctuations due to periodic vortex shedding from the blunt trailing edge of a coated airfoil are examined theoretically, and the strength of the shed vorticity is determined in terms of the form drag of the airframe.
7 citations
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TL;DR: In this paper, a finite element displacement method for linear bending deformation was used to predict the bending up to a central transverse displacement equal to about the plate thickness, providing certain modelling conditions are used.
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TL;DR: In this article, the bandstructure for complex wavevector for bulk semiconductors in the [100] and [111] directions has been calculated using a layer method, a technique that utilises empirical pseudopotentials.
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TL;DR: In this paper, a classical, two-dimensional, geometric, non-linear, finite element is reported which predicts displacements, strains and stresses in laminated plates, and it is shown that the element is inaccurate when predicting experimental deformation for reasons given.
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TL;DR: In this article, an n-type doped amorphous-silicon Schottky barrier was used to estimate the density of states in the upper half of the mobility gap.
Abstract: Experimental admittance measurements are presented for an n-type doped amorphous-silicon Schottky barrier. The measurements are shown to be quite consistent with the theory described by Archibald and Abram (1983, 1986) and, using this theory, an estimate of the density of states in the upper half of the mobility gap is calculated. The average value is ∼ 1017 cm−3 eV−1 and there is a minimum situated approximately 0˙4 eV below the conduction-band mobility edge. This result is in approximate agreement with the density of states deduced by Lang, Cohen and Harbison (1982) using deep-level transient spectroscopy. The test-fit value for the gap-state capture/emission time constant τ0 is found to be 10−12 s.
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01 Mar 1987TL;DR: In this paper, the variations of the non-dimensionalized inertial coefficients with static eccentricity ratio in the radial and transverse directions are compared with some corresponding values obtained from Reinhardt and Lund (2) and Szeri et al. (3).
Abstract: Inertial coefficients for full squeeze-film bearings are evaluated theoretically using Smith's differential equation relating fluid-film pressure to journal acceleration (1). The variations of the non-dimensionalized inertial coefficients with static eccentricity ratio in the radial and transverse directions are compared with some corresponding values obtained from Reinhardt and Lund (2) and Szeri et al. (3).The results from these three methods show good agreement, especially for short bearings (that is bearings with low values of length–diameter ratio). However, Smith's approach has the advantage of computational simplicity and leads to fairly simple, asymptotic, analytical expressions for very short, and very long, bearings.
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TL;DR: In this article, the authors propose a mechanism whereby reduction in the uncertainty about the ground conditions, achieved by carrying out site investigations work, may be related, through the application of simple probability theory, to a consequent expected loss caused by construction or maintenance.
Abstract: Abtract Planning the development of an urban area is a complex operation in which many disparate objectives and constraints must be reconciled. An attempt is usually made to achieve particular aims at minimum cost. If geological and geotechnical factors are considered in isolation, then a particular structure will cost least to build in locations offering the most favourable ground conditions. Unfortunately, seldom is suitable geological and geotechnical information available at this early stage of development. The paper outlines a mechanism whereby reduction in the uncertainty about the ground conditions, achieved by carrying out site investigations work, may be related, through the application of simple probability theory, to a consequent expected loss caused by construction or maintenance. Thus in planning decisions a financial optimum can be identified in which the cost implications of ground investigations, construction and maintenance can be taken into account.
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TL;DR: In this article, the adhesive fracture energy (GIC) of several adhesive cement systems has been measured at temperatures extending to 700°C using alumina adherends in the double torsion test geometry.
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TL;DR: In this paper, a single steel fastener of circular cross-section has been pulled out of predrilled laminated glass/epoxy composite cylinders located in a pressure cell in which external pressures of up to 56 MPa were applied.
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TL;DR: This paper suggests a technique known as the hemispherical projection method for the plotting of three-dimensional joint mobility data and suggests 'indices of mobility' may be derived from the plots which could be used to quantify joint disability using the area enclosed by, and the asymmetry of, the plot.
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TL;DR: In this paper, the longitudinal strain distributions of reinforced concrete tension members were measured using internally strain gauging the reinforcing rods and the results from ten test specimens of varying lap length and rod diameter have been produced.
Abstract: Strain measurements along lapped joints in reinforced concrete tension members were obtained using a method of internally strain gauging the reinforcing rods. Strain concentration gauges, installed at the lap ends of some specimens, demonstrated the localised nature of force transfer prior to crack formation.
Results from ten test specimens of varying lap length and rod diameter have been produced. The changes observed in the longitudinal strain distributions, and the associated bond and concrete stresses as cracks developed are presented.
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01 Jan 1987TL;DR: The Langmuir-Blodgett (LB) technique is now a well established method for producing ultra-thin films of organic materials on solid surfaces as mentioned in this paper, which can be exploited in electronic and optoelectronic devices.
Abstract: The Langmuir-Blodgett (LB) technique is now a well established method for producing ultra-thin films of organic materials on solid surfaces. These layers can be exploited in electronic and optoelectronic devices[1]. Recent advances in the film deposition equipment allow alternate-layers of different molecules to be built-up. This control of the molecular architecture of organic crystals is unique to the LB technique and permits the fabrication of superlattices with precisely defined symmetry properties. Such molecular assemblies can exhibit pyroelectric, piezoelectric and non-linear optical phenomena.