Showing papers by "University of Salford published in 1969"
TL;DR: In this article, an explanation for cavity formation in dilute solutions of alkali metals in ammonia electrons is proposed, and the metal-non-metal transition in vanadium oxides and doped semiconductors is discussed.
Abstract: In dilute solutions of alkali metals in ammonia electrons are localized in cavities in the solvent, and thermodynamic and transport properties are very similar to those found for dilute solutions of strong electrolytes. At higher concentrations the properties deviate markedly from those of electrolyte solutions and approach those of a liquid metal. In this paper we propose an explanation for cavity formation, and discuss the metal-non-metal transition in the light of recent information about the transition in vanadium oxides and doped semiconductors.
141 citations
TL;DR: In this paper, a theory for the sputtering of amorphous solid by an ion beam and the changes in surface topography to which this sputtering leads is developed, and it is shown that surfaces which have pinning regions such as vertical steps and included impurities reach an equilibrium in which cones are developed on the surface.
Abstract: A theory is developed for the sputtering of amorphous solid by an ion beam and the changes in surface topography to which this sputtering leads. It is shown that surfaces which have pinning regions, such as vertical steps and included impurities, reach an equilibrium in which cones are developed on the surface. The theory is compared with several experimental observations of such conical development.
122 citations
TL;DR: A survey of the distribution of xanthones in angiosperms is given and the various proposals concerning xanthone biogenesis in higher plants are assessed.
107 citations
TL;DR: In this paper, the effect of molding water content and compaction method on the structure of compacted clay is illustrated by the different compression behavior of clays compacted dry and wet of optimum.
Abstract: Compression tests under controlled effective stress paths show the stress path independence of volumetric strain and degree of saturation. Stress path dependency appears to be caused by a reversal in the direction of saturation. The swelling process does not in itself appear to introduce an important path dependency. The collapse mechanism is controlled by a potentially unstable structure, a high applied stress and a high suction pressure. The absence of one of these three factors removes the possibility of significant collapse. The effect of molding water content and compaction method on the structure of compacted clay is illustrated by the different compression behavior of clays compacted dry and wet of optimum. The compression behavior is treated best in terms of the separate components of applied stress and suction pressure, and for one-dimensional compression, the stress-strain relationship for a clay can be stated in a simple form.
100 citations
TL;DR: Using thin layers of cellulose powder and a new pair of solvent systems, forty amino acids and related compounds have been separated unambiguously on a single glass plate by two-dimensional chromatography.
76 citations
TL;DR: In this article, the authors give explicit derivations of expressions for the eigenvalue and eigenvector sensitivity coefficients for the fundamental eigenproblem associated with the behaviour of linear systems governed by equations of the form x = ǫ.
Abstract: Simplo and explicit derivations arc given of expressions for the eigenvalue and eigenvector sensitivity coefficients for the fundamental eigenproblem associated with tho behaviour of linear systems governed by equations of the form x = Ax. Such expressions relating changes in the eigenvalues and eigenvectors of tho matrix A to changes in A have been given by numerous authors since tho early work of Jaeobi (1846). These expressions have been given in various forms and from different points of view, and have also heen derived by a number of different methods. Thus, the sensitivity cigenproblem has been viewed as a problem in numerical analysis (Faddeev and Faddecva 1963, Wilkinson 1965), as a problem in perturbation theory (Bellman 1960, Wilkinson 1965), and as a problem in linear systems theory (Laughton HI64, Mann and Marshall 1965, Mann et al. 1965, Van Ness et al. 1965, Rosenbrock 1965, Morgan 1966 a, b, Nicholson 1967 a, b). It is hoped that this paper may help to clarify n.ny obscurities which may hav...
61 citations
TL;DR: A simple and accurate method has been devised for the quantitative analysis of protein hydrolysates using thin-layer chromatography and the results obtained agree well with those obtained by the ∝Technicon’ Automatic Amino Acid Analyzer and with those given in the literature.
60 citations
TL;DR: In this article, the diffusion constants of oxygen in nickel and α-iron were calculated from experimentally determined internal oxidation rates in dilute silicon-bearing alloys, and the activation energy required for oxygen diffusion was found to be 39.9 kcal/g atom in the range 700 to 850° C.
Abstract: The diffusion constants of oxygen in nickel and α-iron are calculated from experimentally determined internal oxidation rates in dilute silicon-bearing alloys. A single crystal alloy of composition 0.058 wt % silicon in nickel and polycrystalline alloys of composition 0.48 wt % silicon in nickel and 0.072 wt % silicon in iron were oxidised and allowance is made for the absorption of oxygen in the reaction with silicon. For nickel the values of activation energy Q=73.9 kcal/g atom in the range 800 to 1200° C and Q=74.4 kcal/g atom in the range 900 to 1300° C are in good agreement with a previous result. The activation energy required for oxygen diffusion in α-iron was found to be 39.9 kcal/g atom in the range 700 to 850° C.
57 citations
TL;DR: In this paper, a theory was developed that predicts the variation with frequency of the acoustic impedance of a panel sound absorber, taking into account the mass, stiffness and internal damping of the panel; the stiffness of the cavity; and also the effect of introducing a porous material into the cavity.
54 citations
TL;DR: The aim of this paper is to review the requirements of the patient whose upper respiratory tract has been bypassed, to produce a specification for heater-humidifiers which is based on the probable physiological needs of these patients and to assess existing equipment by comparing its performance with that laid down in the specification.
Abstract: The importance of using warm and humid inspiratory gases for patients who are ventilating, spontaneously or not, through a tracheostomy, an endotracheal tube or a nasotracheal tube has been increasingly appreciated in recent years. The complications which can arise when this heating and humidification are neglected are the direct consequence of drying the tracheal mucosa and are manifested clinically as the formation of tenacious, inspissated mucus and encrustation of the trachea 13. Adequate humidification of the inspired gases has been recommended spec.fically for the treatment of tracheobronchitis4,5, severe chest injuries617, head injuries8t9, poliomyelitis 1, pulmonary insufficiency of the new-born 10, pulmonary burns’ 1, for the treatment of infants and children 12-14 and to reduce the risk of tracheo-bronchial infections after tracheostomy 1 5 and fibrinous tracheitis with membrane formation and ulceration 1 6 1 7. There are at present many types of humidifier available and the detailed studies of performance which have been published refer to specific units. The aim of this paper is to review the requirements of the patient whose upper respiratory tract has been bypassed, to produce a specification for heater-humidifiers which is based on the probable physiological needs of these patients and to assess existing equipment by comparing its performance with that laid down in the specification.
52 citations
TL;DR: Two pigments have been isolated from a yeast culture of A. flavus as mentioned in this paper, one of which is identical with a tetrahydroxy-anthraquinone previously isolated from A. versicolor, the other one being aflatoxins M1 and GM1 and for which a tentative structure is put forward.
TL;DR: In this article, the lattice parameters and coefficient of thermal expansion of cubic CdTe in the temperature range 20°C-420°C were measured using a Unicam 19 cm dia. X-ray powder camera.
TL;DR: In this paper, the authors used the mutual irradiation technique for the grafting of acrylic acid in aqueous solution to nylon 6 film in the presence of ferrous, ferric, and cupric salts.
Abstract: The grafting of acrylic acid in aqueous solution to nylon 6 film has been studied in the presence of ferrous, ferric, and cupric salts. The mutual irradiation technique was adopted using a 60Co source. The anions were found to have no effect on the grafting or homopolymerization, but both of these processes were suppressed by the cations in the following order of effectiveness: Cu2+ > Fe2+ > Fe3+. The rate constant for the capture of hydroxyl radicals by acrylic acid has been determined as 6 × 109 1. mole−1 sec−1 by pulse radiolysis using the CNS− competition method. By invoking this result, mechanisms have been suggested for the process of chain termination by metal cations.
TL;DR: Neutron activation analysis was used to determine zinc levels in samples of normal skin taken from 36 cadavers and the gradient in zinc levels between the epidermis and dermis plus the remarkably narrow range of values found in the two structures suggest that this element plays an important role in the metabolism of human skin.
Abstract: SUMMARY.— Neutron activation analysis was used to determine zinc levels in samples of normal skin taken from 36 cadavers. The ratio between epidermal and dermal zinc concentrations was found to be about 6: 1. This gradient in zinc levels between the epidermis and dermis plus the remarkably narrow range of values found in the two structures suggest that this element plays an important role in the metabolism of human skin. The sensitivity of the method used in this study makes it ideal for application to pathological skin conditions where only very small amounts of material are available.
TL;DR: In this paper, it was shown that although the crystallite size is of great importance, it is not necessarily the only factor determining the coercivity of cobalt films, but rather the size of the crystal.
Abstract: Cobalt films, with a small weight percentage of phosphorus, have been made by electroless deposition from hypophosphite baths. A wide variation of their magnetic properties, and in particular coercivity, has been observed. Observations of these films by transmission electron microscopy have demonstrated their particle nature. Attempts are made to correlate the observed coercivity with crystallite (or particle) size, and it is shown that although the crystallite size is of great importance, it is not necessarily the only factor determining the coercivity.
TL;DR: In this paper, the authors developed a nozzle burner, schlieren cone angle method of burning velocity determination, involving measurement of unburnt gas velocity under flame conditions, to permit precise measurements of the burning velocity of inhibited flames.
TL;DR: The performance characteristics of multi-variable model-reference adaptive systems synthesized by Liapunov's direct method are investigated and computer results obtained by simulating the behaviour of several such systems subjected to both constant and time-varying inputs are presented.
Abstract: The performance characteristics of multi-variable model-reference adaptive systems synthesized by Liapunov's direct method are investigated. Computer results obtained by simulating the behaviour of several such systems subjected to both constant and time-varying inputs are presented and discussed in some detail. In each case the time variations of the state variables, the error variables, the adaptive parameters, the Liapunov function and the time-derivative of the Liapunov function are given.
TL;DR: Bond moment constants have been calculated for CO 2, OCS, CS 2, CSe 2 and SCSe 2 using zero-order bond moment theory in this paper, where the constants were derived for CO, OCS and CS 2.
TL;DR: In this article, the 1H magnetic resonance spectra of phenyllithium, meta-and para-tolyllithium and the corresponding chloro derivatives have been analysed and where possible, the results have been compared with previous work.
TL;DR: The theory of modal control is concerned with the design of control loops for systems with governing equations which can be adequately approximated by linear vector-matrix equations of the form where x is the system state vector, y is the control vector, A is the matrix of the uncontrolled system, and B is a control matrix as discussed by the authors.
Abstract: The theory of modal control is concerned with the design of control loops for systems with governing equations which can be adequately approximated by linear vector-matrix equations of the form where x is the system state vector, y is the control vector, A is the matrix of the uncontrolled system, and B is the control matrix.
TL;DR: In this article, interference measurements of the thermal expansion of palladium, silver, and five alloys of these metals were reported in the temperature range 30 to 270 °K and the experimental uncertainties rise from approximately 1% at 270°K to 15% at 30°K. The variation of thermal expansion with concentration is nonlinear and the form of the variation is not substantially affected by temperature in the range covered.
Abstract: Interferometric measurements of the thermal expansion of palladium, silver and five alloys of these metals are reported in the temperature range 30 to 270 °K. The experimental uncertainties rise from approximately 1% at 270 °K to 15% at 30 °K. The variation of thermal expansion with concentration is non-linear and the form of the variation is not substantially affected by temperature in the range covered. A degree of correlation has been found with related thermodynamic properties of the alloys, and the need has been established for a rigorous theory of the thermal expansion of binary alloys on an atomic scale.
TL;DR: In this paper, the absolute threshold of hearing for octave bands of noise with center frequencies from 125 to 4 Hz has been determined and the results show that the noise threshold behaves in a similar fashion to the tone threshold, but below 32 Hz noise thresholds are more sensitive by a small but significant amount.
01 Jun 1969
TL;DR: In this article, the effects of both pressure and velocity induced flow between adjacent recesses were considered in an analysis of multi-recess hydrostatic journal bearings and the performance of the bearing was found to be determined jointly by its pressure ratio, speed variable and the direction of loading.
Abstract: A number of assumptions enable the effects of both pressure and velocity induced flow between adjacent recesses to be included in an analysis of multi-recess hydrostatic journal bearings. Consideration of the rate of energy dissipation within a bearing enables an optimum speed variable to be defined which relates the speed of shaft rotation to the other describing parameters involved. The behaviour of a particular orifice compensated bearing of high aspect ratio was investigated at large values of eccentricity ratio and it was revealed that considerable interaction occurred between the recesses. The performance of the bearing was found to be determined jointly by its pressure ratio, speed variable and, significantly, the direction of loading. Considerable variations inload capacity occurred with changes in these parameters and it is shown that the range of operation of multi-recess bearings may be limited as some recess pressures may drop to the ambient pressure. The application of these results to practi...
TL;DR: Using neutron activation analysis, the copper content of normal skin both from cadavers and biopsy material has been investigated and the results are given.
Abstract: SUMMARY.— Using neutron activation analysis, the copper content of normal skin both from cadavers and biopsy material has been investigated. Thirty seven samples were analysed and the results, given in μg/G of dry weight, were as follows: epidermis 2·23–1510 (mean 7·05); dermis 1·88–6·0 (mean 3·09).
TL;DR: In this article, phase separation techniques have been used to establish the following theta conditions for polytetrahydrofuran : isopropanol at 44.6°C, di-ethyl malonate at 33.5°C and a mixture of ethyl acetate/n-hexane (22.7/77.3 wt.-%) at 30.4°C.
Abstract: Phase separation techniques have been utilised to establish the following theta-conditions for polytetrahydrofuran : isopropanol at 44.6°C, di-ethyl malonate at 33.5°C and a mixture of ethyl acetate/n-hexane (22.7/77.3 wt.-%) at 30.4°C. The entropy, enthalpy, and free energy pair interaction parameters ψ1, ϰ1, and χ1 were also obtained. Light scattering measurements were conducted in isopropanol alone and the second virial coefficient found to be zero, thus verifying theta-conditions. For all three solvent systems the KUHN-MARK-HOUWINK viscosity exponent ν was confirmed to be 0.50, but a unique value was not exhibited by the corresponding KΘ. Some reasons are proposed to account for this. From each KΘ the steric factor σ is calculated to be 1.67 (in isopropanol), 1.69 (in di-ethyl malonate) and 1.75 (in the mixed solvent). These values lie between those for polyethylene oxide and polyethylene.
Mit Hilfe von Methoden zur Phasentrennung wurden die folgenden Theta-Bedingungen fur Polytetrahydrofuran festgelegt : Isopropanol bei 44,6°C, Malonsaureathylester bei 33,5°C und Athylacetat/n-Hexan (22,7/77,3 Gew.-%) bei 30,4°C. Die Entropie-, Enthalpieund Freienergie-Parameter der Paarwechselwirkung ψ1, ϰ1 und χ1 wurden gleichfalls ermittelt. Lichtstreuungsmessungen wurden nur in Isopropanol durchgefuhrt; der zweite Virialkoeffizient war gleich Null, was eine Bestatigung fur die Theta-Bedingungen ist. Der KUHN-MARK-HOUWINK-Viskositatsexponent ν wurde fur alle drei Losungsmittelsysteme als 0,50 bestatigt, dagegen wurde fur die entprechenden KΘ kein einheitlicher Wert gefunden. Um das zu erklaren werden einige Grunde angegeben. Aus KΘ wurde der sterische Faktor σ zu 1,67 (in Isopropanol), 1,69 (in Malonsaureathylester) und 1,75 (imgemischten Losungsmittel) berechnet. Diese Werte liegen zwischen denen fur Polyathylenoxid und Polyathylen.
TL;DR: A method of design is described which avoids the use of admittance charts and can be applied to optimize the performance of an IT system at various stages during its preparation.
Abstract: Induced transmission (IT) filters are compared with other types of narrow-band filters and their advantages outlined on the basis of a general expression for spectral transmittance. A method of design is described which avoids the use of admittance charts and can be applied to optimize the performance an IT system at various stages during its preparation. Finally, methods of monitoring are discussed of with emphasis on the theory of a technique particularly useful for IT filters for the ir.
TL;DR: The morphology of the head and action of the mouthparts during feeding are described for the primitive brachyceran larva, Rhagio scolopaceus, and this is compared with the larva of the stratiomyid, Sargus bipunctatus Scopoli.
Abstract: The morphology of the head and action of the mouthparts during feeding are described for the primitive brachyceran larva, Rhagio scolopaceus. This is then compared with the larva of the stratiomyid, Sargus bipunctatus Scopoli. Both may be found in the same type of habitat, such as dung compost, but whilst Rhagio is a carnivore, Sargus is a detritus feeder. The evolution of the mouthparts is discussed and the mode of feeding of these larvae is compared with that of other Brachycera.
TL;DR: The collective results demonstrate a direct relationship between anionic site-dye binding and metachromasia, although a residual dye binding can be detected by pulse radiolysis when metachromaasia is completely removed.
Abstract: 1. Hydrated electrons produced by pulse radiolysis were used to study the interaction of polyanionic glycosaminoglycans and related compounds with the counterions Methylene Blue and cetylpyridinium chloride. 2. The effect of added salt (potassium chloride) on the interaction indicates that the relative binding affinities, with respect to the types of anionic site present, increases for both counterions in the order CO2−
TL;DR: In this paper, a molecular orbital study has been carried out on nitrous oxide providing a satisfactory description of both the bonding and the low dipole moment whose sense is predicted to be N XXX N → 0.71 mdyneA˚ −1.