Showing papers by "University of Salford published in 1978"
TL;DR: In this article, the authors measured the mean pressure around a circular cylinder placed at various heights above a plane boundary and found that the turbulent boundary layer on the plate at the cylinder position, but with it removed from the tunnel, was equal to 0·8 of the cylinder diameter.
Abstract: The flow around a circular cylinder placed at various heights above a plane boundary has been investigated experimentally. The cylinder spanned the test section of a wind tunnel and was aligned with its axis parallel to a long plate and normal to the free stream. It was placed 36 diameters downstream of the leading edge of the plate and its height above the plate was varied from zero, the cylinder lying on the surface, to 3·5 cylinder diameters. The thickness of the turbulent boundary layer on the plate at the cylinder position, but with it removed from the tunnel, was equal to 0·8 of the cylinder diameter. Distributions of mean pressure around the cylinder and along the plate were measured at a Reynolds number, based on cylinder diameter, of 4·5 × 104. Spectral analysis of hot-wire signals demonstrated that regular vortex shedding was suppressed for all gaps less than about 0·3 cylinder diameters. For gaps greater than 0·3 the Strouhal number was found to be remarkably constant and the only influence of the plate on vortex shedding was to make it a more highly tuned process as the gap was reduced. Flow-visualization experiments in a smoke tunnel revealed the wake structure at various gap-to-diameter ratios.
484 citations
TL;DR: Comparisons between resurfacing endometrial epithelial cells in vivo and epithelium cells migrating from explants in vitro suggested that this initial epithelial migration in vitro was the counterpart of the repair response in vivo.
Abstract: Separation of human endometrium into its epithelial and stromal components has been achieved through collagenase digestion and has permitted a study of these two cell populations under specific experimental culture conditions The stromal cell populations showed a progesterone response, were easily handled in culture, and displayed a limited in vitro life span typical of human diploid fibroblasts In contrast, epithelium only survived in short-term primary culture and showed no clear hormone response High-density epithelial cultures remained viable for longer periods in culture Comparisons between resurfacing endometrial epithelial cells in vivo and epithelial cells migrating from explants in vitro suggested that this initial epithelial migration in vitro was the counterpart of the repair response in vivo
133 citations
TL;DR: In this article, the authors show that the range of possible solutions for any value of tool rake angle and interfacial shear stress is associated with large variations in the curvature of the machined chip.
Abstract: The elimination of a class of possible slip-line field solutions for orthogonal machining indicates that the process is not uniquely defined. The range of possible solutions for any value of tool rake angle and interfacial shear stress is shown to be associated with large variations in the curvature of the machined chip. Machining conditions are split into two types, for one of which the machined chip will always curl, while the other has the Lee & Shaffer slip-line field as a lower limit of the solution range. The extent of the solution range for any value of friction is found to decrease with increasing rake angle. The analysis is shown to be consistent with certain experimental work available.
120 citations
118 citations
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TL;DR: Improved general upper bounds on m ( r, q ) are found, which give m (5, 3)⩽56 as a particular case of an ovaloid in the projective space S r,q of dimension r over a field of q elements.
95 citations
TL;DR: In this article, two aspects of high resolution Rutherford backscattering are treated in some detail: (1) the factors which effectively limit the depth-resolution and (2) the application of low-angle backscatter for surface analysis and channelling studies.
92 citations
TL;DR: In this article, it was suggested that non-crystalline surface layer alloys can be formed in certain metals by ion implantation at large doses, and the mechanism responsible for the "amorphization" is thought to be the same as in this paper.
Abstract: Recent work has suggested that non-crystalline surface layer alloys can be formed in certain metals by ion implantation at large doses. The mechanism responsible for the ‘amorphization’ is thought ...
89 citations
86 citations
TL;DR: In this paper, the influence of polymer additives on the gas-liquid mass transfer in stirred tanks is examined, and an empirical correlation is proposed to explain the viscoelasticity of the PAA solutions.
Abstract: The influence of polymer additives upon the gas-liquid mass transfer in stirred tanks is examined. While the addition of sodium carboxymethyl-cellulose brings about a reduction of the overall liquid side mass transport coefficient which is in line with the predictions by earlier works, the reduction of kLa in polyacrylamide solutions of equal viscosity is much stronger. This is explained by the viscoelasticity of the PAA solutions, and an empirical correlation is proposed.
81 citations
TL;DR: In this paper, measurements on the infrared and laser Raman spectra of some lead silicate glasses of general formula (PbO)x(SiO2)y are presented.
Abstract: Results are presented of measurements on the infrared and laser Raman spectra of some lead silicate glasses of general formula (PbO)x(SiO2)y. For the infrared spectra, the frequency dependence of the imaginary component of the complex dielectric constant was determined from a Kramers-Kronig analysis of the reflectance spectra of the glasses at normal incidence. Apparently the addition of small amounts of PbO to vitreous silica serves to modify the continuous three-dimensional silica network; whereas in those glasses with a high lead content, the influence of the cation, Pb2+, appears to lie between that of network former and network modifier.
81 citations
TL;DR: These ultrastructural changes are not specific for bleomycin, but represent a general reaction of the lung to injury, and did not bear a constant time relationship to the dosage schedule.
Abstract: The pulmonary changes produced in mice given bleomycin intraperitoneally (twice weekly for 4 weeks, total dose 240 mg/kg) were examined by light and electron microscopy. Bleomycin damaged the pulmonary vessels and produced type I pneumocyte necrosis, resulting in non-uniform pulmonary fibrosis. The sequence of events leading to pulmonary fibrosis may be arbitrarily divided into three phases: firstly, a focal perivascular lesion consisting of interstitial oedema with plasma cell and lymphocyte infiltration; followed by the middle proliferative phase characterised by type I pneumocyte necrosis, intra-alveolar fibrin deposition, an increase in the numbers of type II pneumocytes and fibroblasts and an overall decrease in the alveolar diameter. The third phase consisted of organisation, with intra-alveolar and interstitial collagen formation and the synthesis of elastin. These phases, although occurring sequentially, did not bear a constant time relationship to the dosage schedule, for new early focal lesions continued to appear throughout the period of the experiment. These ultrastructural changes are not specific for bleomycin, but represent a general reaction of the lung to injury. The exact mechanism whereby bleomycin produces the lung damage has yet to be ascertained.
TL;DR: In this article, primary photochemical processes in aqueous solution have been characterised for FMN and the influence of pH on these processes is attributed to protonation of the neutral triplet and not to the presence of a dimeric species as postulated earlier.
Abstract: — Primary photochemical processes in aqueous solution have been characterised for FMN. The influence of pH on these processes is attributed to protonation of the neutral triplet and not to the presence of a dimeric species as postulated earlier. Second order rate constants for reaction between the neutral triplet and some naturally occurring amino acids are reported.
TL;DR: In this article, the principal linear thermal expansion coefficients of a tridirectional (−45°, 0°, +45°) carbon fiber reinforced plastics laminate are reported in the approximate temperature range 90 K to 500 K.
Abstract: Measurements of the principal linear thermal expansion coefficients of a tridirectional (−45°, 0°, +45°) carbon fibre reinforced plastics laminate are reported in the approximate temperature range 90 K to 500 K. A quantitative evaluation of the in-plane results in thermoelastic terms has yielded an agreement with these results consistent with the approximations and uncertainties involved. The qualitative agreement with expectations based upon the behaviour of unidirectional and bidirectional laminates is also demonstrated. The account concludes with an examination of some effects which are peculiar to multidirectional laminates.
TL;DR: In this paper, a detailed analysis of the generation and potential recrystallization of amorphous zones resulting from ion irradiation of solid materials is given, where the criterion for generation of such spikes is considered to be that sufficient energy is deposited locally to induce melting.
Abstract: A detailed analysis of generation and potential recrystallization of amorphous zones resulting from ion irradiation of solid materials is given. The criterion for generation of such spikes is considered to be that sufficient energy is deposited locally to induce melting. Subsequently the heated zone is considered to cool via unperturbed thermal diffusion from an initial temperature distribution of Gaussian form, although the expected ellipsoidal geometry is idealized to spherical symmetry for analytical convenience. Recrystallization is considered to occur via a thermally activated process during spike quenching and criteria for crystallization at both zone boundaries and centres are deduced. These criteria are shown to correspond well to earlier analyses, but other parameters such as substrate temperature and energy deposition density are found to be of considerable importance. Suggestions for more accurate modelling are also examined.
TL;DR: In this article, the dispersion relations for magnetic excitons propagating on the hexagonal sites of double-hcp Pr when uniaxial stress is applied along the $[1\overline{2}10]$ direction were examined.
Abstract: Neutron inelastic scattering techniques have been used to examine the dispersion relations for magnetic excitons propagating on the hexagonal sites of double-hcp Pr when uniaxial stress is applied along the $[1\overline{2}10]$ direction. The mode of lowest energy (longitudinal optic) along $\ensuremath{\Gamma}M$ was found to exhibit a clear soft-mode behavior with increasing stress. Elastic satellite reflections corresponding to long-range magnetic ordering in a longitudinally modulated structure were observed: at 800 bars the N\'eel temperature is 7.5 K.
TL;DR: It is inferred that human diffuse alveolar damage develops in the same way as experimental bleomycin damage in mice where it has been shown that the changes are the result of vascular damage and type I pneumocyte necrosis.
Abstract: The pathology of two cases of pulmonary damage due to bleomycin is described. The drug damages the alveolar walls. A sequence of pathological changes could be traced commencing with oedema, intra-alveolar fibrin and haemorrhage, followed by type II pneumocyte hyperplasia associated with bronchial epithelial squamous metaplasia. This led to intra-alveolar and alveolar wall collagen formation producing diffuse interstitial fibrosis with microcyst formation associated with cuboidalization of the epithelium. These changes are similar to those seen in experimental bleomycin damage in mice, where it has been shown that the changes are the result of vascular damage and type I pneumocyte necrosis. It is inferred that human diffuse alveolar damage develops in the same way.
TL;DR: In this article, a mechanism for the formation of malonaldehyde in irradiated pentoses, disaccharides, and polyhydroxy alcohols has been proposed, which is based on pulse radiolysis and 60Co γ-radiolysis.
TL;DR: A random search algorithm (Controlled Random Search) for the solution of constrained non-linear minimisation problems and its effectiveness in solving 13 chemical engineering steady-state optimisation examples is demonstrated.
TL;DR: In this paper, it was shown that E and A values for solid-state decompositions are environmentally dependent and that values calculated from rising temperature experiments should not necessarily agree with those obtained from the more traditional isothermal experiments.
TL;DR: In this paper, an algorithm is presented which greatly facilitates the complete exploitation of state feedback in the assignment of the entire closed-loop eigenstructure of controllable multi-input systems.
Abstract: In this paper an algorithm is presented which greatly facilitates the complete exploitation of state feedback in the assignment of the entire closed-loop eigenstructure of controllable multi-input systems. This algorithm is a generalization of the algorithm of MacLane and Birkhoff (1968) for the computation of a basis for the null space of a matrix and is ideally suited to digital computer implementation. The algorithm readily yields the vectors which are required (Porter and D'Azzo 1978) for the simultaneous assignment of Jordan canonical forms, eigenvectors, and generalized eigenvectors to the plant matrices of closed-loop controllable multivariable linear systems. The effectiveness of the algorithm is illustrated by assigning the entire closed-loop eigenstructure of a third-order two-input discrete-time system in such a way that the resulting closed-loop system exhibits time-optimal behaviour.
TL;DR: In this article, preferential sputtering of a binary alloy is considered using diffusion theory and it is shown that this leads to nonlinear terms in both the bulk diffusion equation and the boundary conditions.
Abstract: The preferential sputtering of a binary alloy is considered using diffusion theory It is shown that this leads to non-linear-terms in both the bulk diffusion equation and the boundary conditions The steady-state solution is investigated in detail, and the results indicate that some of the non-linearities are negligible, while others cannot be omitted without appreciable errors The surface depletion of the more volatile component is much smaller than earlier diffusion studies had suggested
TL;DR: In this article, the bipartite Ramsey number R(m,n) is defined as the smallest integer p such that any 2-colouring of the edges of the complete bipartitite graph Kp, v forces the appearance of a monochromatic Km, n.
Abstract: Beineke and Schwenk [1] have defined the bipartite Ramsey number R(m,n), for integers m, n (1≤m≤n ), to be the smallest integer p such that any 2-colouring of the edges of the complete bipartite graph Kp, v forces the appearance of a monochromatic Km, n. In [1] the following results are established:with equality if there is a Hadamard matrix of order 2(n−1), n odd,if there is a Hadamard matrix of order 4(n−1),
TL;DR: In this paper, the densities of a series of V2O5/P2O-5 glasses in the approximate concentration range 26-53 mol% P2O 5 are reported.
Abstract: Measurements of the densities of a series of V2O5/P2O5 glasses in the approximate concentration range 26–53 mol% P2O5 are reported. The apparent molar volume of oxygen is essentially constant in this series of glasses. The structural implications of this result are discussed.
TL;DR: The application of matrix isolation infrared and Raman spectroscopy to the study of the self-association of hydrogen bonding substances is discussed in this article, where the results of far infrared spectral studies enable some of the hydrogen bond stretching and bending modes of these species to be identified.
TL;DR: In this article, the authors compared sets of polyester condensates in gas-liquid chromatography by determination of their polarity constants both from the Rohrschneider probes at low temperature and usign a set of aromatic probes at high temperature.
TL;DR: In this article, a model for preferential sputtering based upon a preferentially enhanced diffusion of one species over a finite depth in the solid which acts as a continuous atomic supply to the surface is considered.
Abstract: The preferential sputter enrichment or depletion of a species in a binary solid is a well established experimental observation. This composition change is usually found to occur over a depth similar to that of the penetration depth of the sputtering projectile. This paper therefore considers a model for preferential sputtering based upon a preferentially enhanced diffusion of one species over a finite depth in the solid which acts as a continuous atomic supply to the surface. Exact solutions are determined for steady state surface and depth distributions of the composition ratio of the two species for the time dependent behaviour of these concentration distributions. The results are compared with models which assume equal diffusion enhancement of both species over both limited and infinite depth and with experimental studies.
TL;DR: The macroinvertebrate benthos of the River Irwell is impoverished to an extent that cannot be explained solely in terms of organic pollution as discussed by the authors, and it appears that high pH leads to rapid precipitation of the discharged metals to substrate materials.