Showing papers by "City University London published in 1969"

High Performance, Platinum Activated Tungsten Oxide Fuel Cell Electrodes

Abstract: HYDROCARBON fuels (methane, propane and so on) are relatively inert and can only be electrochemically oxidized using either high loading noble metal-black electrodes in phosphoric acid at 150° C or high temperature molten carbonate (or solid oxide) electrolyte cells at 600–1,000° C (ref. 1). Alternatively the fuel may be “reformed”, producing impure hydrogen (containing carbon dioxide and some carbon monoxide) which may be fed into a low temperature (> 100° C) acid fuel cell. Carbon monoxide, however, poisons platinum black by strongly adsorbing on its surface (with high coverage) at normal fuel cell anode potentials. Little opportunity exists for water molecules to adsorb on sites adjacent to surface CO molecules—a necessary condition for the removal of the latter by anodic oxidation2

Changes in nerve terminals and acini of the lacrimal gland and changes in secretion induced by autonomic denervation

Abstract: Nerve terminal alterations induced by superior cervical ganglionectomy and pterygopalatine ganglion lesions, and acinus cell alterations induced by the latter operation and by greater petrosal neurectomy, established that a majority of interstitial and all parenchymal nerve terminals of the lacrimal gland in monkeys were parasympathetic. These were shown to originate from neurones of the pterygopalatine ganglion. A minority of interstitial terminals were sympathetic and were distinguished from the remainder by the presence of small granular vesicles. The number of small granular vesicles was increased by iproniazid treatment.

Structure and Performance of Hydrophobic Gas Electrodes

Abstract: HYDROPHOBIC gas electrodes can demonstrate high performance even at ambient temperatures1. These electrodes are made by mixing a finely divided catalyst, such as Pt black, with polytetrafluoroethylene (PTFE) dispersion and applying the mixture to a porous conducting substrate, such as a metal screen. The electrodes are dried and cured at 300° C for 1 h.

Adhesion of Polyethylene to Metals

Abstract: THE adhesion of polyethylene to high energy substrates depends on the oxidation of the polymer. Better adhesion was found1 to copper if it was covered with CuO rather than Cu2O, because the former oxidizes the polyethylene; and the adhesion to Duralumin is increased2 when polyethylene is oxidized with dichromate or permanganate. The high adhesion of polyethylene to steel can be depressed by antioxidant in the polymer3, and the poor adhesion to glass is enhanced by use of a suitable oxidizing agent. We now report circumstances, however, in which the adhesion of polyethylene is dependent not on oxidation but on the hitherto neglected concept of mechanical “keying”.

Tunnelling between Metallic Islands on a Dielectric Substrate

Abstract: THE electrical conduction mechanism in ultra-thin metallic films as formed by vacuum evaporation has been the subject of considerable experimentation, theoretical conjecture and analysis. Such films can exist as a planar array of discrete islands, typically some tens of Angstroms across and similar distances apart, supported by a dielectric substrate such as glass. One of the important conduction processes occurring on application of an electric field across the aggregate of islands is quantum mechanical tunnelling of electrons between islands through the substrate as propounded by Neugebauer and Webb1, and it is this particular mode we are concerned with here.

Compression of Aluminium up to About 200 kbar and Evidence of a Structure Change

Abstract: THEORETICAL calculations of compression (the ratio of volume, V, at high pressure, relative to the volume, V0, at ambient pressure) have evolved largely because of inadequacies in the quadratic expression used by Bridgman1 in his early investigations above about 30 kbar.

A Joint Pseudo-splitting/Peroxide Mechanism for Oxygen Reduction at Fuel Cell Cathodes

Abstract: THE performance of low temperature fuel cells is usually limited by the speed of the cathodic reduction of oxygen, One explanation of the slowness of the reaction is the need to break the O—O bond, which requires considerable energy, even for oxygen in the adsorbed state. An alternative explanation1–3 is that the reaction is slow because it can occur only at scarce favourable sites on the electrode surface. This mechanism, called pseudo-splitting, accounts for the nature of oxygen electrode polarization curves and predicts that the electrode current density i will be proportional to the square root of p, the oxygen partial pressure.

Design of bandpass digital filters

Abstract: A method for synthesizing bandpass digital filters is described and illustrated by a particular example. This method rests on a complex plane mapping performed on the z plane, and has several advantages over others proposed by various authors.

Mechanical Interpretation of Maxwell's Equations

Abstract: THROUGHOUT the nineteenth century there were intensive efforts to develop mechanical models of electromagnetic phenomena based on the hypothesis of a linear aether continuum pervading all space1. One of the most interesting models was the gyrostatic aether proposed by MacCullagh in 1837, a medium characterized by resistance to rotation but not to compression or distortion, and designed to secure a dynamical foundation for Fresnel's wave theory of light2. This proposal lay dormant until taken up again many years later by Fitzgerald (1880), followed by Kelvin (1892) and Larmor (1894), who assimilated it to Maxwell's field equations. Larmor pictured the electron as a nucleus of rotational strain in the gyrostatic aether, thereby partially anticipating Volterra's3 dislocation singularities which may exist in an elastic continuum. Although Larmor's electron as it stands is incapable of motion, it marked a distinct advance over alternative conceptions, including that of Lorentz (1892), which insisted on an inexplicable dichotomy between the aether and ordinary matter. This supposed dichotomy was responsible for many paradoxes and, in spite of Larmor's suggestion, prevented a rapprochement with the new relativity physics in 1905. An aether with mechanical properties completely imaging electromagnetic phenomena, and containing mobile singularities imaging material particles, would be perfectly compatible with the Special Theory of Relativity. It would, however, go beyond that theory in also providing a rational theory of matter. The purpose of this communication is to introduce the gyrostatic aether on a fresh mathematical basis, capable of assimilating charges and currents as well as fields, and thereby fulfilling the primary condition of any acceptable aether hypothesis. An extended development will be presented elsewhere.

Standards in education in information science

Abstract: The courses in Information Science at the City University (formerly Northampton College of Advanced Technology), which started with a two‐year part‐time evening course in January 1961, were the first in the world to attempt to cover the whole field of information work as a definitive discipline. They were based on the syllabus devised by the Institute of Information Scientists. The success of the evening course led to the establishment of a full‐time one‐year course in September 1963. Drexel College of Technology, in the United States, had started a one‐year course earlier in 1963. The original one‐year course in London was for an academic year, and led to a Diploma. When the College became the City University, in 1967, the full‐time course was extended to a calendar year, and this leads to the degree of Master of Science in Information Science. Researches are also being undertaken.

The housekeeping of housekeeping a library furniture and equipment inventory program

Abstract: Dr. Herbert Coblans recently remarked in a paper on the mechanisation of documentation that ‘today we can see that the achievements are not so much in the automation of information retrieval as at the level of housekeeping operations …. in libraries’. A description of an operational method of handling The City University library accounts using the computer appeared in Program and since publication it has been developed to remove major limitations, notably the upper financial limit.

The Supersonic Aerothermopressor

Abstract: This paper describes the results of an experimental investigation carried out on a small-scale aerothermopressor both in subsonic and supersonic flow These are compared with numerical solutions of the equations originally derived by Shapiro In subsonic flow the agreement between theory and experiment closely follows that of previous investigators but in supersonic flow there is a considerable difference between the estimated and measured static pressure distribution along the duct Photographic studies of the initial break-up of the water spray in supersonic flow show that the spray does not distribute itself uniformly across the duct as in subsonic flow A variety of techniques of water injection designed to overcome this shortcoming are described and some improvement is possible However, this discrepancy between theory and experiment is still so great that it appears that the supersonic aerothermopressor must be inferior to its subsonic counterpart

The Dynamic Characteristics and Control of a Hydraulic Turbine

Abstract: A dynamic model of a radial flow turbine was derived. The model was verified by tests on an experimental 5 hp Francis type turbine. The tests indicate that the model is adequate for control system design. A simulation of the model was used to study possible forms of turbine control. The studies demonstrated the advantages of simple adaptive and feedforward control.

Stresses in compact end closures for cylindrical pressure vessels.

Abstract: Three different assumptions are made for the behaviour of the junction between the cylindrical shell and the end closure.Comparisons of analytical and experimental results show that the inclusion of a ‘rigid’ annular ring beam at the junction of the cylider and the closure best represents the shell behaviour for a ratio of cylinder mean radius to thickness of 3–7, and enables a prediction of an optimum vessel configuration to be made.Experimental verification of this optimum design confirms the predictions.(The special use of the term ‘rigid’ is taken in this context to refer to a ring beam for which deformations of the cross-section are ignored but rigid body motion is permitted.)