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Showing papers by "University of Huddersfield published in 1970"


Journal ArticleDOI
TL;DR: The 57Fe Mossbauer spectra of the iron carbonyl derivatives [CH3SFe(CO)3]2, [C5H5Fe (CO)2] 2, C8H8Fe( CO)3, C4H4Fe2SnCl3 at −196°C and +25°C were compared.

23 citations


Journal ArticleDOI
TL;DR: This paper describes a practical geometric error compensation system that can be applied to any machine tool that has up to 5 axes that can correct for the effects of all the geometric errors associated with a machine's linear axes, together with a fork type servo head.
Abstract: Compensation is a recognised technique for correcting the systematic errors inherent to machine tool positioning systems. It offers a cost effective and flexible solution to the problem of enhancing machine accuracy. In spite of this controller manufacturers provide limited facilities for applying compensation, and in many cases linear positioning compensation only is available. The main reason for this is the potential complexity of a comprehensive compensation system able to cope with the variety of axis combinations and configurations available in the modern machine tool market. This problem is compounded by the demand from industry for precision 5 axis machining. This paper describes a practical geometric error compensation system that can be applied to any machine tool that has up to 5 axes. The system can correct for the effects of all the geometric errors associated with a machine's linear axes, together with the geometric errors associated with a fork type servo head. The system applies compensation dynamically and in real time as the machine moves throughout its working volume.

11 citations


Journal ArticleDOI
TL;DR: In this paper, a new approach to the modelling and simulation of a CNC machine tool axis drive is presented, which allows greater flexibility in the construction of the model and an investigation of the interaction between model components.
Abstract: The paper presents a new approach to the modelling and simulation of a CNC machine tool axis drive. Modules have been created for different parts of the CNC machine tool. This allows greater flexibility in the construction of the model and an investigation of the interaction between model components. In this way all the shortcomings of the traditional methods are overcome. MATLAB / SIMULINK package has been used to simulate this new model for a CNC machine tool. Simulation results are very good, in accordance with CNC machine tool theory. The described approach allows the easy construction of detailed machine tool drive models. It represents the basis for future incorporation of geometric, non-rigid and thermal models of machine tool behaviour.

11 citations


Journal ArticleDOI
01 Jan 1970
TL;DR: The field of public relations is often misunderstood due to its hybridity, complexity and competing perspectives within the field of scholarship as discussed by the authors, which is reflected in variations in understanding of the role public relations in theory and practice, ranging from an idealised conceptualisation of the practitioner to a demonised view of the practice.
Abstract: The field of public relations is often misunderstood, due to its hybridity, complexity and competing perspectives within the field of scholarship. This essay, which is based on extensive engagement with literature conducted over decades of teaching and researching the subject, outlines the main schools of thought within the field. These are summarised as a) Excellence; b) Advocacy; c) Dialogue; and d) Critical and Cultural approaches. Each perspective reflects variations in understanding of the role of public relations in theory and practice, ranging from an idealised conceptualisation of the practitioner to a demonised view of the practice. It refers throughout to different attitudes to ethics found within these schools, as approaches to ethics provide insight into understandings of the role of public relations within society. The piece concludes with reflections on the growing engagement with promotional culture and emerging research directions.

9 citations


Journal ArticleDOI
TL;DR: In this article, the application of elastohydrodynamic theory and the Blok flash temperature criterion to cylindrical involute worm gears consisting of phosphor bronze wormwheels driven by casehardened steel worms is discussed.
Abstract: Some initial observations are made on the application of elastohydrodynamic theory and the Blok flash temperature criterion to cylindrical involute worm gears consisting of phosphor bronze wormwheels driven by casehardened steel worms. It is shown that deliberately introduced stress maldistributions can cause predictable pitting in wormwheels and use is made of an S/N curve for phosphor bronze to estimate the surface fatigue life of some wormwheels. The theoretical work is supported by exploratory tests using both worm gears and a disc machine. Some results of film thickness measurements are included. It is shown that, within the limits of design and manufacturing practicalities, the behaviour of worm gears can be predicted quantitatively. The theory and experimental results have been presented with a view to stimulating interest in and, it is hoped, more rigorous studies of, this somewhat neglected field. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Confere...

8 citations


Book ChapterDOI
01 Jan 1970
TL;DR: In this article, the wave nature of light and the properties of different optical instruments were examined under polarized light, which enables the amount of strain at certain points of the structure to be estimated.
Abstract: This chapter presents the details of examination of the wave nature of light and the properties of different optical instruments. The resolving power of a telescope is the reciprocal of the smallest angle, which the line joining the two stars subtends at the objective of the telescope for which resolution of the images is just apparent. If a beam of polarized light is passed through solutions of certain substances, for example, sugar, the plane of vibration is turned through a certain angle that is proportional to the length of the path of light in the solution and to its concentration. It depends also on the nature of the substance in solution. The substance is said to be optically active. Some transparent substances become doubly refracting when subjected to stress. Examination under polarized light of models of structures made from such substances enables the amount of strain at certain points of the structure to be estimated.

7 citations



Book ChapterDOI
01 Jan 1970
TL;DR: In this article, the authors discuss surface tension, quantitative measure, angle of contact, and other aspects of surface tension using three methods, which are: (1) use of capillary tube, where glass capillary tubes are used; (2) second method measures the pull on a wire frame across which a film of liquid, such as soap solution, is formed; and (3) if a glass microscope slide is used in place of a wireframe, a modification of this method may be used for liquids that do not easily form films.
Abstract: Publisher Summary This chapter discusses nature, quantitative measure, angle of contact, and other aspects of surface tension. The work done to increase the area of a liquid surface by unit area at constant temperature is called its surface tension. Surface tension is, thus, not an elastic stretching force because such a force increases in proportion to the amount of stretch. Surface tension decreases, in general, as the temperature increases. In measuring surface tension, it is important that the liquid surface be clean. The angle between the bounding plane and the tangent to the liquid surface at the point of contact is called the angle of contact. The experimental determination of surface tension can be done using three methods, which are: (1) use of capillary tubes, where glass capillary tubes are used; (2) second method measures the pull on a wire frame across which a film of liquid, such as soap solution, is formed; and (3) if a glass microscope slide is used in place of a wire frame, a modification of this method may be used for liquids that do not easily form films. The Jaeger's bubble method is most suitable for measuring the surface tension of a liquid at various temperatures.

3 citations


Journal ArticleDOI
TL;DR: In this article, the authors present a general software which is capable of analysing the geometric and thermal errors in any structure consisting of measurable struts, such as the tilt of a spindle or the length of a strut.
Abstract: There is currently much interest in non-Cartesian machines in the machine tool industry. The analysis of errors arising from component variations in geometry and temperature is far more complex than in the case of the Cartesian machine. This is because the errors are no longer additive along each axis. This paper describes techniques leading to the development of general software which is capable of analysing the geometric and thermal errors in any structure consisting of measurable struts. This limitation is not so restrictive as it might appear, since solid components can usually be modelled as interconnected struts if large temperature gradients do not produce high stresses within their volume. The software also provides an animated display showing the moving structure. The techniques described constitute three efficient matrix methods which can be programmed in a general way. The approach is to break down a machine into sub-assemblies and to analyse each of these individually. The subassemblies are brought together into an overall model and the predictions of errors, such as the tilt of a spindle, are evaluated. Each sub-assembly can be assigned an average temperature or each strut can be treated separately. Hence, the errors arising from a source of heat, such as a spindle motor, can be evaluated, as can the effect of random errors in strut lengths. Three dimensional plots of errors in any plane are available.

3 citations


Journal ArticleDOI
TL;DR: In this article, the results of tests on dyeings of selected reactive dyes on cotton, carried out to distinguish between the various chemical classes and to place them in their apparent position in Clayton's tables, are described.
Abstract: The reactive systems and chromogens present in further types of reactive dyes are briefly discussed. The results are described of tests on dyeings (or prints) of selected reactive dyes on cotton, carried out to distinguish between the various chemical classes and to place them in their apparent position in Clayton's Tables. Particular attention is paid to the black reactive dyes, and a scheme is proposed for differentiating between dyeings of 25 different black reactive dyes on cotton.

2 citations


Journal ArticleDOI
TL;DR: A new expert system for addressing machine tool accuracy problems, designed for use in industry, and using a descriptive graphical user interface for retrieving information about the current machining application, and displaying information regarding possible strategies for improvement.
Abstract: The costs of addressing machining accuracy problems can often appear to exceed the perceived benefits of reducing rework or scrap etc. These costs arise from assigning time and resources to analysing and fixing the problems. There may also be costs associated with consultancy if the required expertise is not available in-house. When accuracy problems are addressed, a lack of knowledge in certain areas may lead to unsatisfactory solutions. This paper introduces a new expert system for addressing machine tool accuracy problems. The goal of this software is to be a Machine Tool Error Identification and Compensation Advice System (MTEICAS). Although in its early stages, the concepts and reasons behind the development of the software are described. An expert system development tool called Visual Prolog is being used to create the program, providing a number of advantages over traditional procedural languages such as C. Designed for use in industry, the software employs a descriptive graphical user interface for retrieving information about the current machining application, and displaying information regarding possible strategies for improvement. Utilising a comprehensive and easy to use help system, the software will guide the user through many aspects of machine tool calibration and implementation of compensation strategies. To provide validation, a number of users with varying levels of experience will apply the system in real applications. Transactions on Engineering Sciences vol 23, © 1999 WIT Press, www.witpress.com, ISSN 1743-3533

Book ChapterDOI
01 Jan 1970

Journal ArticleDOI
TL;DR: Transformation matrices are used to transform the nodal equations into a new set of equations that contains voltage and current vectors related to the two ports of interest.
Abstract: The representation of a network by its indefinite admittance matrix and the subsequent reduction to a nodal matrix is easily achieved. Any set of linear equations can be reduced by matrix partitioning to a 2×2 matrix; however, it is important to realize that if the easy-to-set-up nodal matrix is reduced, the resultant two-port representation has a node common to the input and output ports. The reduction procedure can also be applied to two-ports such as lattice networks and difference amplifiers that do not have a node common to the ports of interest. The lack of the common node means that reduction of the nodal matrix is no longer applicable and the nodal equations must therefore be transformed into the required form before the reduction procedure is used. Transformation matrices are used to transform the nodal equations into a new set of equations that contains voltage and current vectors related to the two ports of interest.

Book ChapterDOI
01 Jan 1970
TL;DR: In this article, features of viscosity and different properties of viscous matters are presented, where the shape of a substance changes continually with time when subjected to distorting forces that are held constant, and the substance is said to be viscous.
Abstract: Publisher Summary This chapter presents features of viscosity and different properties of viscous matters. If the shape of a substance changes continually with time when subjected to distorting forces that are held constant, the substance is said to be viscous, and the substance possesses viscosity. Viscosity may be considered to be that property of a fluid that causes it to resist change of shape and which results in internal frictional forces when there is relative motion between different parts of the fluid as it flows under the action of external forces. In the case of laminar flow of liquid through a tube, the thin layers of liquid that slide over each other are concentric cylinders. Any instrument used for the measurement or comparison of viscosities is called a viscometer. The study of viscosity and its measurement is of major importance in connection with lubrication and the use and the development of lubricating oils. Laminar, or streamline, flow is possible provided the velocity of flow is not too great and, in the case of flow through a narrow channel, provided the radius of the bore of the channel is not too great.

Book ChapterDOI
01 Jan 1970
TL;DR: In this article, the authors highlight the illumination properties and the concept of photometry, and define the luminous intensity of a source as the quantity of luminous flux emitted per unit solid angle by a source of unit intensity, assuming it emits uniformly in all directions.
Abstract: This chapter highlights the illumination properties and the concept of photometry. The direct measurement of the strength, or intensity, of a source of light, as the energy emitted by it in unit time in the form of radiation in the visible region of the spectrum, is not easily achieved. The modern unit of luminous intensity is called the new candle or candela. It is defined as the luminous intensity of a source is one-sixth part of the luminous intensity of a source consisting of 1 cm 2 of a black body, or full, radiator at the melting point of platinum, viewed normal to the surface. The light energy emitted per unit time from a source is referred to as luminous flux and the unit is the lumen. This is defined as the quantity of luminous flux emitted per unit solid angle by a source of unit intensity, that is, 1 cd, assuming it emits uniformly in all directions. The illumination of a surface is defined as the quantity of luminous flux falling on unit area of that surface. The luminous intensity of a source may not be the same in all directions. The reflection factor of a surface is defined as the fraction of the incident light that is reflected by it.