Showing papers by "University of Manchester published in 1976"
TL;DR: Coronary heart disease and mental ill health together, therefore, represent a serious cost for industry both in human and financial terms.
Abstract: Felton & Cole (1963) estimate that all cardiovascular diseases accounted for 12 per cent of the time lost by the ‘working population’ in the US, for a total economic loss of about $4 billion in a single year. A report (1969) by the Department of Health and Social Security in the UK shows, as Aldridge (1970) indicates, that the sum of incapacity for men suffering from mental, psychoneurotic and personality disorders, nervousness, debility and migraine headache accounted for 22·8 million work days lost in 1968 alone (second only to bronchitis in the league table of illness and lost working days). Coronary heart disease and mental ill health together, therefore, represent a serious cost for industry both in human and financial terms.
1,213 citations
TL;DR: In this paper, the authors examined the oxidation behavior of an Fe-27%Cr-4%Al alloy and similar alloys containing 0.023% and 0.82% Y in 1 atm oxygen at 1200°C and found that the oxide formed on the yttrium-free alloy develops a highly convoluted configuration, resulting from lateral growth of the oxide.
Abstract: The oxidation behavior of an Fe-27%Cr-4%Al alloy and similar alloys containing 0.023% and 0.82% Y in 1 atm oxygen at 1200°C has been examined. The oxide formed on the yttrium-free alloy develops a highly convoluted configuration, apparently resulting from lateral growth of the oxide. The latter leads to oxide detachment from the alloy at temperature and extensive spalling during cooling. It is postulated that lateral growth results from the formation of oxide within the existing oxide layer by reaction between oxygen diffusing inward down the oxide grain boundaries and aluminum diffusing outward through the bulk oxide. Additions of yttrium to the alloy apparently prevent the formation of oxide within the oxide layer, the oxide-forming reaction occurring as the alloy-oxide interface. Thus lateral growth is prevented and spalling during cooling does not occur. Secondary advantages conferred by the addition of 0.82% Y to the alloy are the prevention of void formation at the alloy-oxide interface, the avoidance of alloy grain growth during oxidation, and the creation of an oxide “keying” or “pegging” effect.
434 citations
TL;DR: The processes of visual detection and of temporal and spatial summation may be analyzed in terms of parallel luminance (achromatic) and opponent-color systems; a test flash is detected if it exceeds the threshold of either system.
Abstract: We show how the processes of visual detection and of temporal and spatial summation may be analyzed in terms of parallel luminance (achromatic) and opponent-color systems; a test flash is detected if it exceeds the threshold of either system. The spectral sensitivity of the luminance system may be determined by a flicker method, and has a single broad peak near 555 nm; the spectral sensitivity of the opponent-color system corresponds to the color recognition threshold, and has three peaks at about 440, 530, and 600 nm (on a white background). The temporal and spatial integration of the opponent-color system are generally greater than for the luminance system; further, a white background selectively depresses the sensitivity of the luminance system relative to the opponent-color system. Thus relatively large (1 degree) and long (200 msec) spectral test flashes on a white background are detected by the opponent-color system except near 570 nm; the contribution of the luminance system becomes more prominent if the size or duration of the test flash is reduced, or if the white background is extinguished. The present analysis is discussed in relation to Stiles' model of independent eta mechanisms.
432 citations
TL;DR: Computed tomography, employing an EMI scanner at two beam energies, can be used to obtain information about the electron density and the effective atomic number of materials.
Abstract: Computed tomography, employing an EMI scanner at two beam energies, can be used to obtain information about the electron density and the effective atomic number of materials. The theory which is discussed has been verified experimentally and then applied in the investigation of some brain tumours in vivo. It is anticipated that, as techniques improve, the ability to carry out chemical and physical analysis of pathological processes in vivo will be an important application of computed tomography.
286 citations
TL;DR: The effects of case detection and treatment were beneficial and immediate, with the duration of episode of the disorder being much shorter for patients whose disorder was recognised by the general practitioner and so receiving treatment.
281 citations
271 citations
TL;DR: In contrast to the stan-dard hierarchy of K. de V. equations found by Lax, these equations do not appear to fit the present inverse formalism or possess the various properties associated with it such as Backlund transformations as discussed by the authors.
Abstract: We have found new hierarchies of Korteweg–de Vries and Boussinesq equations which have multiple soliton solutions. In contrast to the standard hierarchy of K. de V. equations found by Lax, these equations do not appear to fit the present inverse formalism or possess the various properties associated with it such as Backlund transformations. The most interesting of the new K. de V. equations is ( u nx ≡ ∂ n u /∂ x n ) ( u 4 x + 30 uu 2 x + 60 u 3 ) x + u t = 0. We have proved that this equation has N -soliton solutions but we have been able to find only two soliton solutions for the rest of this hierarchy. The above equation has higher conservation laws of rank 3, 4, 6 and 7 but none of rank 2, 5 and 8 and hence it would seem that an unusual series of conservation laws exists with every third one missing. Apart from the Boussinesq equation itself, which has N -soliton solutions, ( u xx + 6 u 2 ) xx + u xx – u tt = 0 we have found only two-soliton solutions to the rest of this second class. The new equations have bounded oscillating solutions which do not occur for the K. de V. equation itself.
260 citations
TL;DR: The conformational role of a side chain is shown to be dependent on hydrophobicity and its ability to receive or donate a hydrogen bond and the application of the parameters to making predictions is demonstrated by a worked example for hen egg whito lysozyme.
257 citations
TL;DR: In this article, the wavelength dependence of interstellar linear polarization [p(λ) was investigated using the usual Serkowski relation with three parameters: p max, λ max, and K. Optical and infrared measurements were obtained simultaneously in eight photometric passbands between U and K, giving a coherent data set for a total of 105 reddened stars.
Abstract: New observations of the wavelength dependence of interstellar linear polarization [p(λ)] made to investigate the influence of the environment on the effective size distribution of the aligned polarizing particles are presented. Optical and infrared measurements were obtained simultaneously in eight photometric passbands between U and K, giving a coherent data set for a total of 105 reddened stars. The p(λ) data were modeled using the usual Serkowski relation with three parameters: p max , λ max , and K
249 citations
TL;DR: In this paper, an exact matrix method of solution to the Maxwell-Stefan equations is used for calculating multicomponent gas phase mass transfer coefficients and transfer rates. But the results are seen to be exact matrix analogues of classical binary relations and may also be applied as an approximation to describe liquid phase transport.
Abstract: Convenient expressions for calculating multicomponent gas phase mass transfer coefficients and transfer rates are obtained by use of an exact matrix method of solution to the Maxwell-Stefan equations. The results are seen to be exact matrix analogues of classical binary relations and may also be applied as an approximation to describe liquid phase transport.
198 citations
TL;DR: The contrast “halving” technique failed to demonstrate a sense of absolute contrast for inexperienced observers, but observers familiar with contrast were able to assess contrast linearly, and according to its suprathreshold value.
TL;DR: A new method for vehicle scheduling, based upon sequential generation of vehicle routes, is described in this paper, and the possibility of several journeys being made by each vehicle is actively considered, and vehicle utilisation is high in consequence.
Abstract: Sequential and concurrent route building methods for planning multiple drop delivery journeys are contrasted, and it is concluded that the former would offer important practical advantages if the quality of the routes could be improved. A new method for vehicle scheduling, based upon sequential generation of vehicle routes, is described in this paper. The possibility of several journeys being made by each vehicle is actively considered, and vehicle utilisation is high in consequence. The Clarke and Wright savings criterion is generalised, and each journey is automatically free from intersections. The method is also computationally efficient as evidenced by a study of the sensitivity with respect to fleet size, of changes in vehicle capacity and a driven distance constraint for a single depot problem with 225 customers.
TL;DR: In this article, the conformation of monofilaments of poly(tetramethylene terephthalate) has been determined using the techniques of X-ray diffraction.
01 Jan 1976
TL;DR: Sewall Wright has provided the best general classification of the processes changing gene frequency under the simplified conditions outlined in Chapter 1, and it is used in the following account.
Abstract: Micro-evolution consists of change in the population either to fit it to a new place or time in a changing environment, or to improve its success in a constant environment. The modifications which take place are genetic. Sewall Wright pointed out in an article written in 1949 that ‘the elementary evolutionary process in a reasonably large homogeneous population maybe considered to be change in gene frequency’. He has provided the best general classification of the processes changing gene frequency under the simplified conditions outlined in Chapter 1, and it is used in the following account.
TL;DR: Application to recent data enables w(λi) to be expressed as an explicit algebraic function, from which it appears that the earlier conclusions of Rivlin & Saunders require some modification in detail.
Abstract: The mechanical properties of a rubber may conveniently be represented in terms of the strain energy $W$, which in Rivlin's notation is expressed as a function of the strain invariants $I\_{1}$ and $I\_{2}$. The experiments of Rivlin & Saunders indicated that $\partial W/\partial I\_{1}$ was approximately constant while $\partial W/\partial I\_{2}$ varied with $I\_{2}$, in contrast to the Mooney equation, according to which both $\partial W/\partial I\_{1}$ and $\partial W/\partial I\_{2}$ are constant. More recently it has been proposed by Valanis & Landel that $W$ may be expressible in terms of separate functions $w(\lambda \_{i})$ of the principal extension ratios $\lambda \_{i}$. This hypothesis appears to be borne out experimentally, and gives promise of a more accurate analysis of experimental measurements. Application to recent data enables $w(\lambda \_{i})$ to be expressed as an explicit algebraic function, from which it appears that the earlier conclusions of Rivlin & Saunders require some modification in detail.
TL;DR: Comparing the absolute response rates in component A during Phase I and Phase II it was found that introduction of the concurrent schedule did not affect the value of the theoretical maximum response rate, but did increase thevalue of the reinforcement frequency needed to obtain any particular submaximal response rate.
Abstract: During Phase I, human subjects pressed a button for monetary reinforcement in five variable-interval schedules, each of which specified a different frequency of reinforcement. The rate of responding was an increasing, negatively accelerated function of reinforcement frequency; the data conformed closely to Herrnstein's equation. During Phase II, the same five schedules were in operation, but in addition a concurrent variable-interval schedule (B) was introduced, responses on which were always reinforced at the same frequency. Response rate in component A increased while the response rate in B decreased, as a function of the reinforcement frequency in component A. Relative response rates in the two component schedules matched the relative frequencies of reinforcement. Comparing the absolute response rates in component A during Phase I and Phase II it was found that introduction of the concurrent schedule did not affect the value of the theoretical maximum response rate, but did increase the value of the reinforcement frequency needed to obtain any particular submaximal response rate.
01 Jun 1976
TL;DR: Two possible formulations of the problem are presented that permit the probability-density curves of the angles, voltages, injected reactive powers and active and reactive power flows to be computed.
Abstract: The paper extends the presently available techniques for evaluating the load flow problem probabilistically. It presents two possible formulations of the problem that permit the probability-density curves of the angles, voltages, injected reactive powers and active and reactive power flows to be computed. Owing to the complexity of the problem, the load-flow equations were linearised. The errors introduced by this technique together with the results of a typical analysis are discussed.
TL;DR: In this paper, the behaviour of 2 in. dia., 0.064 in. thickness and of lengths ranging from 2 − 24 in. was examined. And three modes of deformation were identified and analyzed on the basis of plastic work considerations.
TL;DR: In this article, the experimental results obtained in an experimental investigation of heat transfer to supercritical and subcritical pressure CO2 flowing through a uniformly heated 2214mm ID horizontal pipe are presented, covering a flow inlet Reynolds number range of about 2 × 104 to 2 × 105 Marked peripheral temperature variations are obtained which represent the influence of buoyancy comparison with buoyancy free data.
TL;DR: The paper describes an efficient algorithm for evaluating the minimal cut sets of any general network based on Boolean algebra and set theory, and contains many important improvements.
Abstract: The paper describes an efficient algorithm for evaluating the minimal cut sets of any general network. The algorithm is based on Boolean algebra and set theory, and contains many important improvements. The four most important features are 1. only one set of topological input data is required to evaluate the minimal cuts and reliability indices of every output node; 2. a mix of undirectional, bidirectional and multi ended components can be included very simply; 3. any number of input nodes may be specified; 4. a new concept of overall system reliability permits different, large, and complex systems to be compared. The computational efficiency of the algorithm is clearly indicated by the fact that the time required to analyse Example 1 on a CDC7600 was 0.7 sec. The storage required with the appropriate arrays dimensioned for a system having 100 components and up to 125 minimal cut sets per output node is 15 k-words. These times and storage include the overall system reliability analysis.
TL;DR: In this paper, it was shown that the generalized sine-Gordon equations do not have an auto-Backlund transformation between solutions $z and $z^{\prime} if and only if $F$ and $G$ are solutions of the same function.
Abstract: The generalized sine-Gordon equations $z\_{,xt}=F(z)$ in two independent variables $x$, mi include the sine-Gordon $z\_{,xt}=$sin z and the multiple sine-Gordon's like $z\_{,xt}$ = sin $z+\frac{1}{2}$ sin $\frac{1}{2}z$. Among other physical applications all these sine-Gordon's are significant to the theory of intense ultra-short optical pulse propagation. The sine-Gordon itself has analytical multisoliton solutions. It also has an infinity of polynomial conserved densities and has auto-Backlund transformations which generate a second solution of the sine-Gordon from a first solution - particularly from the solution $z\equiv 0$. We prove first that the generalized multi-dimensional sine-Gordon in two or more space variables $x^{1},x^{2}$... has no auto-Backlund transformations. Next we prove that the generalized sine-Gordon's $z\_{,xt}=F(z)$ and $z\_{,xt}^{\prime}=G(z^{\prime})$ have an invertible Backlund transformation between solutions $z$ and $z^{\prime}$ if and only if $F$ and $G$ are solutions of $\ddot{F}=\alpha ^{2}F,\ddot{G}=\beta ^{2}G$ where, in general, $\beta =\alpha h^{-1},\alpha $ is a complex number and $h^{2}(
eq 0)$ is real. In case $h$ = 1 and $F$ and $G$ are the same function $z\_{,xt}=F(z)$ has an auto-Backlund transformation if and only if $\ddot{F}=\alpha ^{2}F$. We exhibit the B.ts and a.B.ts in these cases as well as the other B.ts for the generalized sine-Gordon. We conclude that the multiple sine-Gordon's do not have a.B.ts and infer that, despite the soliton character of the numerical solutions, the multiple sine-Gordon's are not soluble by present simplest formulations of the two by two inverse scattering method.
TL;DR: It is suggested that the marked lysosomal activity during early pregnancy is related to the architectural refashioning of the placenta during this period and that there are two phosphatase-linked transfer systems in the trophoblast, one dependent upon acid-phosphatases-containing multivesicular bodies and being utilised during earlyregnancy and the other reliant upon alkaline phosphatases and dominating during the second half of gestation.
Abstract: The subcellular localisation of acid and alkaline phosphatase has been studied in the trophoblast of placentae from both normal and complicated pregnancies. In placentae from uncomplicated pregnancies the number of trophoblastic acid-phosphatase-containing organelles decreases progressively as gestation proceeds whilst alkaline-phosphatase activity, although abundant at term, could not be demonstrated during the early stages of pregnancy. The acid-phosphatase-containing organelles are of two types; one is a small round body which is probably a lysosome whilst the other is a multivesicular body. The alkaline phosphatase is distributed mainly on the syncytial microvilli and plasma-membrane. It is suggested that the marked lysosomal activity during early pregnancy is related to the architectural refashioning of the placenta during this period and that there are two phosphatase-linked transfer systems in the trophoblast, one dependent upon acid-phosphatase-containing multivesicular bodies and being utilised during early pregnancy and the other reliant upon alkaline phosphatase and dominating during the second half of gestation. In placentae from prolonged pregnancies there is a further decrease in trophoblastic acid phosphatase and, usually, a continuing increase in alkaline-phosphatase activity. In placentae from babies of low birth weight this trend is sometimes reversed and alkaline-phosphatase activity either disappears or its reaction product diffuses throughout the syncytium; this is usually accompanied by a marked increase in the number of acid-phosphatase-containing multivesicular bodies. Placentae from women with pre-eclampsia show no loss of alkaline-phosphatase activity but are characterised by an increased number of lysosomal bodies.
TL;DR: In this paper, the behavior of simply supported circular tubes under the action of the transverse loading of a wedge-shaped indenter up to the point of maximum load is examined.
TL;DR: The mean serum level of 24,25-dihydroxycholecalciferol in seven normal volunteers was 1.68 ± 0.82 ng/ml whereas patients receiving large therapeutic doses of vitamin D were found to have higher levels and none was detectable in the serum of a vitamin D-deficient patient.
01 Jan 1976
TL;DR: In this paper, arehaeological, palaeoecological, ethnographic and land management evidence is presented which supports the hypothesis of regular and recurrent burning by mesolithic hunting populations in the southern Pennine uplands over a c. 4000-year period.
TL;DR: With the assumption of a fixed photon flux, it is shown that two optimum energies exist for the measurement of effective atomic number and that if energies of 40 keV and 80 keV are employed, a precision of at least 1 part in 400 may be achieved.
Abstract: The measurement of the effective atomic number of a piece of material in vivo can be achieved using computed tomography. The precision of measurement of this parameter depends on the precision of measurement of the X-ray absorption coefficient at two energies and the separation of these energies. With the assumption of a fixed photon flux, it is shown that two optimum energies exist for the measurement of effective atomic number. The analysis indicates that if energies of 40 keV and 80 keV are employed, a precision of at least 1 part in 400 in the measurement of effective atomic number may be achieved.