Showing papers by "University of Leeds published in 1972"
TL;DR: In this paper, the variation of burning velocity with equivalence ratio for methane-air mixtures at one atmosphere pressure values were determined by the bombhot wire and corrected density ratio techniques, for combustion during the prepressure period.
431 citations
TL;DR: It is shown that major congenital malformations occurred in their children with twice the expected frequency, and, while anticonvulsant drugs may have a teratogenic action mediated by interference with folic-acid metabolism, suchTeratogenic activity is likely to be influenced by hereditary and environmental factors.
400 citations
TL;DR: In this article, a critical survey of different experimental techniques for the measurement of burning velocity is presented, with particular reference to the maximum burning velocity of methane-air mixtures, and recommendations are made as to the most suitable methods of measuring burning velocity for both closed vessels and burners.
363 citations
TL;DR: A new algorithm is presented that allows routes from several depots to be constructed simultaneously, subject to restrictions on numbers of vehicles at individual depots, and a flexible priority rule will select those to be served.
Abstract: The problem of scheduling delivery vehicles from a number of depots to customers, subject to constraints on load and distance or time, is considered. A new algorithm is presented; this allows routes from several depots to be constructed simultaneously, subject to restrictions on numbers of vehicles at individual depots. Where too many customers require service, a flexible priority rule will select those to be served. Results for the single depot case are compared with other known algorithms; further results are given and discussed for cases of several depots.
277 citations
TL;DR: In this article, the authors collected eolian dust from the marine atmosphere of the major wind systems along the eastern margins of the Atlantic Ocean between c. 27°N and c. 34°S.
191 citations
TL;DR: The entry of immunoblasts into “free” grafts of syngeneic foetal gut, implanted subcutaneously, and the entry of xenogeneic immunoblast into normally situated gut are studied.
Abstract: SINCE the observations of Gowans and Knight1 it has been shown that many of the lymphoid blast cells (immunoblasts) that appear in the thoracic duct lymph of rats after immunization of the caudal lymph nodes with a variety of antigens “home” to the lamina propria of the small gut2, where they differentiate into plasma cells3. The immunological specificity of the immunoblasts, however, does not seem to affect their affinity for the small gut2,3. Recent work4 has shown that immunoblasts home just as readily to the small gut of unsuckled, neonatal rats obtained by Caesarian section, in which the gut is sterile and presumably antigen-free, and where there is no influence of endogenous or maternal colostral immunoglobulins. The entry of immunoblasts into the lamina propria must involve the transmigration of these cells across the vascular endothelium. The first event in such a process may be the engagement of a receptor on the surface of the immunoblast with a complementary group on its endothelial surface. We have studied the entry of immunoblasts into “free” grafts of syngeneic foetal gut, implanted subcutaneously, and the entry of xenogeneic immunoblasts into normally situated gut.
189 citations
TL;DR: In this article, a second order analysis has been made of the aerodynamic growth of sinuous waves on parallel sided inviscid liquid sheets and equations have been derived which describe the characteristics of the fundamental mode and the first harmonic.
Abstract: A second order analysis has been made of the aerodynamic growth of sinuous waves on parallel sided inviscid liquid sheets and equations have been derived which describe the characteristics of the fundamental mode and the first harmonic. A solution has been obtained for the case where the wavelengths are relatively long compared with the sheet thickness and it is found that thinning of the sheet is caused by the growth of the harmonic wave, maximum thinning and subsequent rupture occurring at positions corresponding to $\frac{3}{8}$ and $\frac{7}{8}$ of the length of the fundamental wave. The solutions have been utilized to calculate the break-up lengths of attenuating sheets and the results are compared with measured values.
169 citations
TL;DR: In a double-blind trial in thirty-six patients who had not required hospital admission for at least 2 years on prophylactic lithium, six out of the eighteen patients on placebo relapsed within 6 months, compared with only one of the 18 patients continuing to receive lithium.
146 citations
141 citations
122 citations
TL;DR: A subjective survey of sleep was carried out on 100 women who were 38 or more weeks pregnant, finding that most women reported some change in their sleep, in some cases throughout the pregnancy, but in most cases the change had occurred only in the third trimester.
TL;DR: A longitudinal study of 127 children between the ages of 11 and 17 years revealed a high initial prevalence of gingivitis that tended to decline slightly with age that was consistent with the hypothesis that there is a relationship between puberty and gingIVitis.
Abstract: A longitudinal study of 127 children between the ages of 11 and 17 years revealed a high initial prevalence of gingivitis that tended to decline slightly with age. The distribution of the ages of the children when experiencing their observed maximum amount of gingivitis was consistent with the hypothesis that there is a relationship between puberty and gingivitis. There was also evidence that at the time of the peak gingivitis experience the gingival tissues were exhibiting a heightened response to irritation.
TL;DR: A close visual examination of the three cereals after steeping revealed, that the seed coats of corn and sorghum were essentially intact, while those of millet had ruptured extensively.
Abstract: Ogi was prepared in the laboratory from three cereals -corn, sorghum and millet, in accordance with traditional Nigerian practice. The material balance of the process showed the lowest recovery of Ogi from millet. Similiarly, the protein balance indicated the highest losses with millet. The maximum moisture contents of the grains on prolonged steeping were lower in corn and sorghum than in millet. A close visual examination of the three cereals after steeping revealed, that the seed coats of corn and sorghum were essentially intact, while those of millet had ruptured extensively. Proximate analyses of the materials during and at the end of processing showed losses of some nutrients, but no significant change in overall amino acid patterns.
TL;DR: In this paper, the evolution of the Troodos Massif is discussed and a model of magmatic processes beneath active ridges is presented, based on the model presented in this paper.
Abstract: The evolution of the Troodos Massif is discussed and a model of magmatic processes beneath active ridges presented.
TL;DR: The kinship system, which is generally accorded a central place in social anthropological analyses is, in this case, relegated to the background as discussed by the authors in the Muslim rural society of West Punjab.
Abstract: Underlying much of the literature on South Asian rural societies is the assumption that these societies are structurally similar, if not identical in every detail, and that the distinguishing feature of the structure of social institutions in those societies is their focus on caste and the related jajmani system as bases of social organization. The kinship system, which is generally accorded a central place in social anthropological analyses is, in this case, relegated to the background. In the Muslim rural society of West Punjab, however, the contrary is true. There it is the kinship system rather than caste which embodies the primodial loyalties which structure its social organization.’ .
TL;DR: It was concluded that the basic assumption implicit to gravimetric and indicator techniques, i.e. that all material contained within the faeces is derived from the food, does not generally hold and a new radiotracer technique analogous to indicator methods has been developed.
Abstract: Gravimetric, radiotracer, and indicator methods currently available for estimating assimilation efficiencies, have been reviewed and their associated limitations have been discussed. It was concluded that the basic assumption implicit to gravimetric and indicator techniques, i.e. that all material contained within the faeces is derived from the food, does not generally hold. Radiotracer techniques are not based on this assumption but are time consuming. Consequently a new radiotracer technique analogous to indicator methods has been developed. In this technique the concentration of a non-absorbed indicator is expressed in terms of a radiotracer, 14C, which can be absorbed but which, at least initially, is only present in the food, rather than expressing it in terms of dry weight. 51Cr has been used as the nonabsorbed indicator.
TL;DR: In this paper, the high temperature deformation properties of three titanium alloys, copper-zinc and copper-aluminium alloys have been determined, and the significance of these results in the general interpretation of superplasticity is discussed.
TL;DR: The importance of an accurate knowledge of thermal accommodation coefficient at larger values of Kn is discussed in this article, where hot wires have been calibrated in the regime 0 400, 0.02 < Re < 20 and with property values taken for the mean gas temperature.
TL;DR: In this article, a new method for assessing crystallinity in cellulosic materials has been established after a rigorous computational analysis of X-ray diffraction traces from the highly crystalline fibrous forms of cellulose I and II, Ramie and Fortisan.
TL;DR: In this paper, the effects of rotational anisotropy on the mean apparent resistivity and azimuthal inhomogeneity ratio obtained in square array measurements are reviewed.
Abstract: An account is given of the use of the square array technique in investigating the surface effects of rotational anisotropy when the axes of anisotropy are inclined to the surface. It is shown that, as with other arrays, two anisotropy parameters and n can be derived by varying the array orientation.
On the basis of these considerations, the effects of such anisotropy on the values of the mean apparent resistivity and azimuthal inhomogeneity ratio normally obtained in square array measurements is reviewed.
Particular attention is paid to the variation of resistivity with orientation and it is noted that, in areas of moderate anisotropy, this variation is lower for the square than for the Schlumberger array.
In addition to this advantage, the azimuthal inhomogeneity ratio obtained from square array measurements may be used to indicate the severity of anisotropy in an area and two field examples of this use are given.
Where anisotropy is severe, gross variations of apparent resistivity with orientation are obtained with either square or collinear arrays. In these circumstances, the use of crossed measurements is considered and the particular stability of the crossed square array demonstrated.
TL;DR: In this article, the effects of uniform blowing and suction on the free convection boundary layer on a vertical plate are considered, and a numerical solution of the full boundary layer equations is obtained in both cases.
TL;DR: The Limpopo Orogenic Belt is a linear zone of gneisses separating the adjacent granite-greenstone cratons of Rhodesia and the Transvaal.
Abstract: The Limpopo Orogenic Belt is a linear zone of gneisses separating the adjacent granite-greenstone cratons of Rhodesia and the Transvaal Previous age data suggested that the high-grade gneisses in the belt were formed 2,000 my ago In this Rb-Sr age study, three whole-rock isochrons and two mineral isochrons were obtained as well as 28 other isotope dilution analyses on minerals and whole rocks from scattered localities A concordant isochron for the syngenetic Bulai and Singelele granites in the center of the belt yields an age of 2,690 ± 60 my The age dates the formation of these rocks and, in addition to other evidence, indicates that the main folding and metamorphism dates back to 2,700 my The average of 20 biotite and K-feldspar ages, however, confirms a strong thermal event at 2,000 ± 70 my Equilibration of Sr isotopes at 2,000 my in the Limpopo Belt can be related to intrusive and other contemporaneous events in southern Africa and may reflect the widespread “Eburnean” orogenic event in Africa The formation of the Limpopo gneisses around 2,700 my appears to be related to the widespread “Shamvaian” orogeny which strongly affected the Rhodesian and Transvaal cratons
TL;DR: The Cenozoic volcanic activity in northeastern Nigeria began with the intrusion into the Benue trough of a trachyte-phonolite suite of plugs 22-11 m.y. as discussed by the authors.
Abstract: The Cenozoic volcanic activity in northeastern Nigeria began with the intrusion into the Benue trough of a trachyte-phonolite suite of plugs 22-11 m.y. ago. Later activity, which was more widespread and dominantly basaltic in character, began some 7 m.y. ago and has continued until very recent times. It resulted in basaltic plugs and lava plateaux within the Benue trough, and cinder cones and lavas on the Jos Plateau.
TL;DR: The fermentation rate and carboxylic acids of Ogi, a Nigerian fermented cereal porridge, have been investigated and the acidity of steeped grain was evaluated, with lactic, acetic and butyric acids being the most important.
Abstract: The fermentation rate and carboxylic acids of Ogi, a Nigerian fermented cereal porridge, have been investigated. As a measure of fermentation rate, the acidity of steeped grain was evaluated by extracting the acids with a suitable solvent and titrating against a standard alkali. Since the method is time consuming, the titratable acidity of the aqueous centrifugate may be preferred in routine quality control operations. The carboxylic acids of Ogi fermentation were analysed using paper, gas-liquid and thin-layer chromatography. Eleven acids were identified, lactic, acetic and butyric acids being the most important.
TL;DR: The ecological significance of the environmental complex governing the expression of a ‘sediment factor’ is discussed in relation to the kelp fauna and the difficulty of accurately interpreting data on faunal dynamics is outlined in the light of these and other factors.
TL;DR: The plasmalemma of Oocystis apiculata, W. West when freezeetched has been shown to bear granules of several sizes, which are seen to change so that in the final stages it bears reticulate invaginations, the granule bands occurring within them.
Abstract: The plasmalemma of Oocystis apiculata, W. West when freezeetched has been shown to bear granules of several sizes. At the earliest stage of development the outer face of the plasmalemma of the naked autospore has small (8.5 nm diameter) granules aligned in rows, in pairs. These rows are stacked together forming extensive “granule-bands” over the plasmalemma surface. The orientation of these “granule-bands” corresponds exactly to one of the major microfibril directions. Occasionally, the bands are reduced to patches, some of which are at right angles to each other. Banding of granules on the inner plasmalemma face of naked autospores is also seen. During development the plasmalemma is seen to change so that in the final stages it bears reticulate invaginations, the granule bands occurring within them. The significance of the “granulebands” in terms of cellulose microfibril biosynthesis is discussed.
TL;DR: The hypothesis that argE and argCBH form two operons transcribed in opposite directions from an internal promoter-operator complex is discussed, and it is suggested that a secondary promoter exists at or near the argB-H boundary.
Abstract: In Escherichia coli K12, four of the nine structural genes involved in the biosynthesis of arginine (argE, C, B and H) form a tight cluster within which a clockwise-polarized unit of expression (argCBH) had previously been identified. From a mutant carrying an argCB deletion that greatly lowers the rate of expression of argE but falls short of known argE markers, we have isolated several derivatives in which the expression of argE is partly restored. In about a third of these strains repression of both E and H enzymes by arginine is almost abolished. The mutations responsible appear to be cis-dominant and to map to the right of argE, probably between argE and C. One mutant in which control of argE alone is affected has also been found; it is shown to carry a duplication of argE in addition to the argCB deletion of the parental strain. We discuss the hypothesis that argE and argCBH form two operons transcribed in opposite directions from an internal promoter-operator complex. It is also suggested that a secondary promoter exists at or near the argB-H boundary.