Showing papers by "Cranfield University published in 1978"
TL;DR: The use of coarse wheat bran, apples, oranges, and carrots is recommended to treat diverticular disease, spastic colon, and constipation.
177 citations
TL;DR: In this article, the viscoelastic creep compliances of various composites are estimated by the self-consistent method with the help of Stieltjes convolutions.
Abstract: In this paper the viscoelastic creep compliances of various composites are estimated by the self-consistent method. The phases may be arbitrarily anisotropic and in any concentrations but we demand that one of the phases be a matrix and the remaining phases consist of ellipsoidal inclusions. The theory is succinctly formulated with the help of Stieltjes convolutions. In order to solve the title problem, we first solve the misfitting viscoelastic inclusion problem. Numerical solutions are given for a selection of inclusion problems and for two common composite materials, namely an isotropic dispersion of spheres, and a uni-directional fibre reinforced material.
157 citations
TL;DR: In this paper, CTBN rubbers were added to DGEBA-type epoxy resins and the structure was varied by altering the type and concentration of hardener, the initial molecular weight of the resin, the amount of Bisphenol A added, and the conditions of cure.
Abstract: Toughened polymers were prepared by adding CTBN rubbers to DGEBA-type epoxy resins. Structure was varied by altering the type and concentration of hardener, the initial molecular weight of the resin, the amount of Bisphenol A added, and the conditions of cure. Electron microscopy showed that these factors affected both particle size and degree of phase separation: rapid curing inhibited phase separation, and produced small particles. Increasing the molecular weight of the resin, either directly or by reaction with Bisphenol A, improved phase separation. Dynamic mechanical measurements of rubber phase volume proved possible, although Tg of the CTBN rubber coincided with a β process in the epoxy resin. Fracture resistance, measured by GIC, increased linearly with rubber phase volume. Creep and yield behaviour were also affected by the degree of phase separation.
148 citations
TL;DR: In this paper, the pattern of fiber orientation in injection moulded strips of glass fibre reinforced polypropylene has been studied using the technique of contact micro-radiography, and it has been found that the fibre orientation in the core of the mouldings is very dependent on injection speed.
Abstract: The pattern of fibre orientation in injection moulded strips of glass fibre reinforced polypropylene has been studied using the technique of contact micro-radiography. It has been found that the fibre orientation in the core of the mouldings is very dependent on injection speed. High injection speed gives alignment of fibres transverse to the flow direction, while for very low speeds the fibres align parallel to the flow. The associated changes in topography of the mouldings have been studied using scanning electron microscopy. The rheological properties of both glass fibre-filled and unfilled polypropylene have been studied in a capillary rheometer. At low shear rates, the fibres cause a significant increase in viscosity, but at the shear rates likely to be encountered in injection moulding, the filled and unfilled melts have very similar viscosities. The rheological data can be used to interpret the pattern of fibre orientation in the mouldings.
121 citations
01 Jan 1978
76 citations
TL;DR: In this paper, a range of commercial aluminium/magnesium alloys were tested at temperatures from 20 to 300°C at a variety of strain rates, and tests were carried out in both uniaxial and baoxial tension.
73 citations
TL;DR: This article conducted a comprehensive review of channels literature, primarily to identify and assess the adequacy of the various mainstream conceptual schemes which have emerged, and concluded that whereas every conceptual approach reviewed has added something to our cumulative knowledge, no single approach has yet reached a point of adequate conceptualisation based on his own basic criteria.
Abstract: Channels of distribution are basic to the marketing strategies of firms, and have been shown to be a key element in the marketing mix. The author here undertakes a comprehensive review of channels literature, primarily to identify and assess the adequacy of the various mainstream conceptual schemes which have emerged. Economic‐based arguments have largely been at the core of channels literature, although these have been partially offset by the concepts of the organisational and behavioural schools. The author concludes that whereas every conceptual approach reviewed has added something to our cumulative knowledge, no single approach has yet reached a point of adequate conceptualisation based on his own basic criteria. As yet channels literature is mainly descriptive, and has virtually no predictive power.
63 citations
TL;DR: In this paper, the influence of ambient pressure and temperature on the amount of spark energy needed to ignite flowing kerosine-air mixtures was investigated using capacitance sparks whose energy could be varied in steps of 2mJ from 2 to 800mJ.
62 citations
TL;DR: In this paper, a comparison of eight methods of representing a general spatial rigid-body screw displacement is made between point transformations and line transformations, and the most commonly used representation is the 4 × 4 real matrix and the conclusion is that this is certainly the best of the point transformations.
Abstract: This paper presents a comparison of eight methods of representing a general spatial rigid-body screw displacement. A distinction is made between point transformations and line transformations. The following three representations involving point transformations are considered: the real 4 × 4 matrix; the complex 4 × 4 matrix; and the real 6 × 6 matrix. These utilise homogeneous coordinates. The remaining five representations considered here are concerned with line transformations and are: the dual orthogonal 3 × 3 matrix; the dual special unitary 2 × 2 matrix; the dual Pauli spin matrices; the dual unit quaternion; and the dual special unitary 3 × 3 matrix. These make use of dual-number techniques. The most commonly used of these representations is the 4 × 4 real matrix and the conclusion reached is that this is certainly the best of the point transformations. The dual unit quaternion is similarly found to be the best of the line transformations.
54 citations
52 citations
TL;DR: In this article, the propagation of disturbances through an atmosphere that is undergoing a spatially uniform chemical explosion is analyzed on the assumption that the disturbances are of small amplitude, and when the latter are arbitrarily small, and therefore classifiable as acoustic, the progress of the ambient explosion is undisturbed to first order and a rather complete history of the acoustic waves including weak shock waves can be constructed.
Abstract: The propagation of disturbances through an atmosphere that is, in its undisturbed condition, undergoing a spatially uniform chemical explosion is analysed on the assumption that the disturbances are of small amplitude. When the latter are arbitrarily small, and therefore classifiable as acoustic, the progress of the ambient explosion is undisturbed to first order and a rather complete history of the acoustic waves (including weak shock waves) can be constructed. The generally amplifying effect of the explosion on the disturbances, which has previously been identified at wave heads, is found to occur throughout the disturbed domains.When the disturbance amplitude becomes comparable to the ratio of the thermal energy of the gas to the combustion-reaction activation energy, the ambient explosion becomes involved in the disturbance to first order. For large activation energies a small disturbance theory can be constructed to account for the disturbance behaviour; at present it is limited to time intervals from initiation that are shorter than the ‘no-depletion’ homogeneous ignition time.
TL;DR: In this paper, a purpose-built environmental chamber housing three creep machines for accurate measurements of creep in a hygroscopic polymer is described, which can limit the error in the measured modulus to ± 0.4% at the 0.1% strain level.
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01 Dec 1978TL;DR: In this paper, the authors present a thorough examination of the phenomena of "threshold" levels of advertising activity and the "wearout" of advertisements and/or campaigns, and suggest that wasted expenditure may be occurring in advertising because the believed levels of threshold and wearout are both too high.
Abstract: This monograph presents a thorough examination of the phenomena of “threshold” levels of advertising activity and the “wearout’ of advertisements and/or campaigns. These are seen as corresponding to the management questions “How little can we spend/How infrequently can we advertise?” and “How much is too much/How infrequently is too little?” In the first section the relevant literature on, or related to, the two issues is reviewed. Section 2 describes a survey aimed at establishing current beliefs in the existence of the phenomena, the practices resulting from these beliefs, and the data which support them. Finally, Section 3 offers an overview on the managerial issues involved in decisions concerning threshold or wearout risks in advertising. It is suggested that wasted expenditure may be occurring in advertising because the believed levels of threshold and wearout are both too high.
TL;DR: In this article, the authors compare the three possible types of complex numbers, i.e., the ordinary complex number, a + ib (where i2 = −1), the dual number, i + ∈b (where ∈2 = 0), and exp(∈τ) which shears the plane parallel to the y-axis through the shear τ.
Abstract: This paper compares the three possible types of complex number. These provide a very concise means for representing certain geometric transformations of the points of a plane. The first type considered is the ordinary complex number, a + ib (where i2 = −1). This is used in the exponential form exp(iα) to rotate the plane through the angle α. The second type is the dual number, a + ∈b (where ∈2 = 0), and exp(∈τ) shears the plane parallel to the y-axis through the shear τ. The third type is the double number, a + jb (where j2 = +1), and exp(jβ) represents another type of shear transformation, known as a Lorentz transformation, which shears the plane through the rapidity β.
TL;DR: The design of man-computer dialogue requires the underlying theoretical framework of basic concepts present in other applied arts, and nonverbal communication should be exploited to widen the rather limited ‘bandwidth’ of current computer terminals.
Abstract: The design of man-computer dialogue requires the underlying theoretical framework of basic concepts present in other applied arts. Four basic aspects of man-computer interaction are predictability, implication (the extensive use made by humans of context), experimentation (the importance of trial and error procedures) and motivation (the part played by feelings such as trust, hostility etc.). Nonverbal communication should also be exploited to widen the rather limited ‘bandwidth’ of current computer terminals.
TL;DR: In this article, the oxidation behavior of a range of nickel-base, high temperature alloys, including Brightray C, Brightray S, Nimonic 90 and Nimonic 105, including IN 713C, IN 587 and IN 597, was studied over the temperature range 850-1050°C.
TL;DR: The effect of both sodium chloride and sodium sulphate contaminant corrosion on the same range of nickel based alloys as tested in oxidation is reported over the temperature range 650-950°C as mentioned in this paper.
TL;DR: Little and Jebe as mentioned in this paper described the statistical design of Fatigue Experiments and used it in the design of a Fatigue Testbed, which they used to evaluate the effectiveness of their experiments.
Abstract: Statistical Design of Fatigue Experiments. By R. E. Little and E. H. Jebe. London, Applied Science Publishers, 1975. ix, 280 p. 23 cm. £10·00.
TL;DR: In this paper, the feasibility of using a fiber optic for transmitting laser light to a vibrating object and scattered light back to a laser-Doppler unit, has been demonstrated, and a new mode of operation of laser Doppler equipment has been devised with marked improvement over the usual Twyman-Green mode.
Abstract: The feasibility of using a fibre optic for transmitting laser light to a vibrating object and scattered light back to a laser-Doppler unit, has been demonstrated. A new mode of operation of laser-Doppler equipment has been devised with marked improvement over the usual Twyman-Green mode. With the aid of this fibre optic laser-Doppler system both frequency and amplitude information can be obtained from otherwise inaccessible machine components.
01 Jan 1978
TL;DR: The interior noise level of a general aviation aircraft under various operating conditions is determined and the major sources of the noise and their relative importance are identified in this article, where a comparison between the interior noise under stationary conditions on the ground and in flight is shown.
TL;DR: The design of man-computer dialog requires the underlying theoretical framework of basic concepts present in other applied arts, and nonverbal communication should be exploited to widen the rather limited `bandwidth' of current computer terminals.
Abstract: The design of man-computer dialog requires the underlying theoretical framework of basic concepts present in other applied arts. Four basic aspects of man-computer interaction are predictability, implication (the extensive use made by humans of context), experimentation (the importance of trial and error procedures), and motivation (the part played by feelings such as trust, hostility, etc.). Nonverbal communication should also be exploited to widen the rather limited `bandwidth' of current computer terminals.
TL;DR: In this paper, an experimental study of the turbulence generated by an enclosed, premixed, propane-air flame has been carried out in a combustion chamber of 25 × 20 cm cross section.
TL;DR: In this article, a light aircraft fuselage was tested to investigate its sound transmission paths and interior noise characteristics, and the acoustic attenuation characteristics and relative effectiveness of different parts of the fuselage for sound attenuation were studied.
01 Jan 1978
TL;DR: In this paper, the authors describe general features of a variety of rubber-toughened polystyrene and the relationship between structure and fracture resistance, and highlight principles of fracture mechanics that begin with the assumption that all materials contain intrinsic cracks, flaws, and other defects.
Abstract: Publisher Summary The principal application of polymer blends is in the manufacture of fracture-resistant plastics, a fact that testifies to the practical importance of fracture properties to the user of plastics products. The fracture resistance of polystyrene can be increased substantially by adding a small proportion of rubber to obtain high-impact polystyrene (HIPS). This chapter describes general features of a variety of rubber-toughened plastics and the relationship between structure and fracture resistance. Study of rubber-toughened plastics shows that phase separation is an essential feature in which the rubber must be dispersed randomly like small discrete particles in the continuous-matrix phase. Other necessary features of the rubber phase are: (a) low shear modulus in relation to the matrix polymer; (b) good adhesion to the matrix; (c) adequate cross-linking; (d) average particle diameter near the optimum value for the material; and (e) low glass transition temperature. The chapter also highlights principles of fracture mechanics that begins with the assumption that all materials contain intrinsic cracks, flaws, and other defects. Four important techniques have been developed for studying rubber toughening. Each technique is capable of yielding quantitative information, therefore, placing the subject on a proper scientific foundation. The techniques are osmium staining, scanning electron microscopy, volumetric strain measurement, and fracture mechanics.
TL;DR: In this paper, the authors argue that the essence of successful management education is a good exchange relationship between the givers and the receivers, and that what we have got to do is to establish a way in which the management educators can work with managers on problems which the latter feel that they have.
Abstract: What is it that managers want from management educators? What is it that management educators can give to managers? I believe that the essence of successful management education is a good exchange relationship between the givers and the receivers. Indeed what we have got to do is to establish a way in which the management educators can work with managers on problems which the latter feel that they have.
TL;DR: In this paper, the rate of amplification of a discontinuity in the slope of the field variables (velocity, pressure, etc.) at the head of a disturbance is evaluated for propagation through a homogeneous exploding atmosphere.
TL;DR: In this paper, the anisotropy of flexural stiffness has been examined at low strain using ASTM bar and 3mm and 6mm thick edge-gated disc injection mouldings for two glass-fibre-reinforced thermoplastics (GFTP).
Abstract: The anisotropy of flexural stiffness has been examined at low strain using ASTM bar and 3-mm and 6-mm thick edge-gated disc injection mouldings for two glass-fibre-reinforced thermoplastics (GFTP). Experimentally determined values were obtained under three-point bending and compared with theoretical prediction: which took account of the fibre orientation and length distributions in the mouldings. The flexural stiffness of the discs was also studied as a function of direction of test.The prediction of the resulting anisotropies in flexure compares well with experiment, but these anisotropies are markedly different from those measured previously in tension. It is concluded that it is necessary to have a knowledge of the fibre distribution of a GFTP moulding in order to predict successfully its mechanical properties, or to interpret measured data.