bluuebunny/crossref_metadata_2025 huggingface dataset:
Residual stress modelling by experimental measurements and finite element analysis
Authors: Beghini M , Bertini L
Published: July 2007

The paper describes an experimental-numerical technique for modelling plane residual stress fields with application to steel slabs containing laser welds of different geometry. This technique is based on the analysis of the strain measured by several small-size strain gauges as a function of the depth of a narrow slot which was cut in the slab itself in small increments. This information was combined with sensitivity coefficients obtained via finite element models in order to derive initial strain distributions for the welded plates. These distributions allowed a prediction to be made of the residual stresses acting in generic bodies extracted from the original plates. The stress fields predicted for square specimens cut from the slabs were then compared with the measured values, showing a fairly good agreement.
A design analysis of steam turbine blade roots under centrifugal loading
Authors: Robertson M D , Walton D
Published: July 2007

Steam turbines are a fundamental component in most electrical power generation systems around the world. Their efficiency and capital cost are dependent on the quality of the blade roots which secure the thermodynamic aerofoil sections to the high speed rotor. This paper outlines a design analysis for such a root system using classical stress analysis and the finite element method. Comparisons are made between the results of both and experimental pull tests. For reasons of simplicity, the analysis considers only the primary centrifugal load on the root and not secondary steam bending loads.
A series solution method for sharp asymmetric dry contact problems
Authors: Myers T G
Published: July 2007

A series solution method is presented for analysing sharp asymmetric dry contact problems. It provides an exact representation for the pressure inside the contact, the contact width and also the displacement outside the contact for the frictionless two-dimensional problem of a rigid indentor acting on an elastic half-plane. The first part of the paper describes how the method can be used for symmetric and asymmetric punches without slope discontinuities. In the second part the method is modified to overcome the Gibbs phenomenon so that it can be applied to any punch, symmetric or asymmetric, with or without slope discontinuities. Finally, two analytic approaches are described and compared with the present solution method.
A transfer matrix method for calculating the elastic behaviour of annular plates
Authors: Crook A W
Published: July 2007

This work arose from a design exercise which required a less constrained treatment of annular plates than is available from standard formulae. The transfer matrix method gives freedom for the thickness of the plate, and the pressure across it, to be any functions of radius, and for the plate to be supported at any radius, or at any radii, in whatever manner is relevant. Natural frequencies and mode shapes may be calculated by including the inertia terms in the matrices. Its limitation is that only axially symmetrical deformation and modes are covered by the method.
X-Ray measurement of residual stresses in a rolled bolt: Application to the calculation of stress intensity factors after cracking
Authors: Toribio J , Campos J M , Sanchez-Galvez V
Published: July 2007

This paper deals with the measurement of the residual stress on the thread root of an M30 bolt. The results are used in the computation of the stress intensity factor – on the cracked bolt – generated by the prior residual stresses. The optimum measurement parameters have been carefully chosen: relative position between the X-ray beam and the sample, and the irradiated spot size. The results are tensile type stresses in the bolt surface – the opposite to the few existing bibliographic data. A test is performed to check the sign of these residual stresses on the externally loaded bolt, and this confirms the results of the first measurement. The stress computation is carried out by the finite element method. The stiffness derivative method is employed to obtain the energy release rate and thus the stress intensity factor.
Low cycle fatigue life predictions for hollow tubes with axially loaded axisymmetric internal projections
Authors: Gowhari-Anaraki A R , Hardy S J
Published: July 2007

The finite element method has been used to study the monotonic and cyclic elastic–plastic stress and strain characteristics of hollow tubes with axisymmetric internal projections subjected to monotonic and repeated axial loading. This paper compares finite element strain predictions with values estimated using simple notch stress–strain conversion equations for two geometries and a range of nominal stresses. From this study, an intermediate equation ( m = 0.5) is suggested for low cycle fatigue life predictions. The results have been normalized with respect to material properties so that they can be applied to geometrically similar components made from other materials which can be represented by the same material models.
Elastic strips in sliding contact
Authors: Jaffar M. J.
Published: July 2007

This paper is concerned with the sliding (full slip) contact between a rigid cylindrical punch and an elastic strip of finite thickness. The strip is either in adhesion with a rigid foundation (bonded strip) or resting on a rigid foundation (unbonded strip). It is assumed that the sliding takes place in one direction on the entire contact surface. The tangential traction q(x) is related to the pressure p(x) by Coulomb's law q(x) = ±μ p(x) where μ is a coefficient of friction. A numerical scheme is developed to reduce the governing integral equation to a system of linear equations. The values of these unknowns will determine the full solution. Results are presented for a wide range of μ, Poisson's ratio #v, and the depth parameter γ(contact halfwidth to depth ratio) and show good agreement with existing results.
Decay rates for the compound circular cylinder
Authors: Stephen N G
Published: July 2007

An exact linear elasticity solution developed by the author for the decay of self-equilibrating end loads applied to a hollow circular cylinder is extended here to determine decay rates for a compound circular cylinder of two materials having different stiffness; only axisymmetric loads are considered. The results are of interest not only as a quantification of Saint-Venant's Principle (SVP), but also because the minimum decay rate indicates the rate of load transfer and hence the maximum extent of a transition region where load is transferred from one cylinder to another. As with the semi-infinite plane strain sandwich, one of the few other geometries amenable to mathematical analysis, rates of decay can be so slow that routine invocation of SVP is not justified.

The rate of load transfer from a stiff inner cylinder to a more flexible concentric cylinder is affected by the ratio of the elastic properties and also the diameter ratio. For load transfer to be effected over minimum distance the difference in stiffness should be small; when the difference in stiffness is large, rapid load transfer can be achieved by keeping the diameter ratio small.
The prediction of axial damping in spiral strands
Authors: Raoof M
Published: July 2007

This paper addresses the problem of predicting the axial hysteresis in multi-layered helical strands from first principles.

Using previously reported orthotropic sheet theory for helical strands with wire compliances derived from results in available contact stress theories, normal forces on the interwire/interlayer contact patches have been estimated. Using such data, the full slip histories on the contact patches from the micro-slips on the periphery at low loads, to the onset of gross slip at higher loads and beyond are predicted. It is shown that cable overall axial hysteresis is dominated by the frictional energy dissipation over the line-contact patches within individual layers.

Strand overall hysteresis is predicted by two rather different theoretical methods which provide an analytical double check. In the first method, the overall load-deflection curve, as derived by a previously reported orthotropic sheet model is used to follow the loading and subsequent unloading response of an axially pre-loaded strand with its ends fixed against rotation. The calculated enclosed hysteresis loop area gives an estimate of strand damping which should closely match alternative predictions based on the summation of energy dissipation over the individual contact patches throughout the strand. The match between these two alternative predictions and available experimental data on some fully bedded-in (old) and substantial 39 mm spiral strand is very encouraging.

The practical limitations of the proposed analytical models are critically addressed in the light of recent experimental findings.
Shear centre of thin-walled sections
Authors: Grant C
Published: July 2007

Shear centre is an important geometric property of thin-walled sections that can be difficult to determine in practice. A computer based solution is developed for sections comprising an arbitrary number of limbs attached to each other at end nodes. Linear equations are identified that are sufficient to determine the shear flow in each limb and the shear centre is derived directly from their solution in a compact, closed form. The method is applied to sections with straight uniform limbs, and a specific example is evaluated.
Development of a full elasto-plastic adhesive joint design analysis
Authors: Crocombe A D , Bigwood D A
Published: July 2007

A previous adhesive joint analysis that accommodated non-linear adhesive behaviour is extended to model the elasto-plastic response of the adherends. The resulting analysis models the joint as an adherend-adhesive sandwich capable of sustaining any combination of end load conditions, thus enabling a wide variety of adhesive joints to be modelled. The adhesive is assumed to behave as a coupled set of non-linear shear and tension springs, and the adherends as cylindrically bent plates which yield under the action of combined tension and bending. The complete problem is reduced to a set of six non-linear first-order ordinary differential equations which are solved numerically using a finite-difference method. In this way a reasonable assessment of adhesive stresses and strains can be obtained easily, without resorting to the complexity of a two-dimensional finite element solution. A comparison between the results from these two methods has been made and is presented in this paper after the outline of the analysis derivations.
Stresses near narrow rectangular notches, with rounded corners, in beams in bending
Authors: Hyde T H , Yaghi A
Published: July 2007

The results of finite element calculations have been used to show that an analytical solution for the stresses in the vicinity of crack-like notches with elliptical and hyperbolic shaped ends gives accurate results for narrow, semi-circular ended notches. It is also shown that the peak stresses can be obtained from the stress intensity factor for an equivalent crack and the notch tip radius. Finite element solutions for narrow, rectangular notches with rounded corners, have also been used to show that the peak stresses in such notches can be obtained by using a notch shape factor to modify the peak stress values for semi-circular notches. The shape factor depends only on the notch width to corner radius ratio.
A photoelastic approach to framed structure-foundation beam-soil interaction
Authors: Chandrashekhara K , Murugappan K R
Published: July 2007

The interaction of a framed structure with a foundation beam resting on an elastic medium, representing the soil, has been studied using the photoelastic method. The contact pressure distribution, the fibre stress in the foundation beam and frame structure, as well as the stresses in the elastic medium, have been obtained. These have been compared with theoretical results obtained by idealizing the soil as (a) elastic half plane, and (b) elastic half space. It is shown that the photoelastic method can provide an easy solution to this type of problem if the soil can be idealized as an elastic continuum.
Experimental investigation of cyclic plasticity continuum damage evolution in an engineering component subjected to thermal loading
Authors: Dunne F P E , Puttergill D B , Hayhurst D R , Mabbutt Q J
Published: July 2007

A thermal shock test facility is designed and built to enable to enable a copper model slag tap component to be tested under cyclic thermal loading conditions. Infra-red line heaters and pumped cooling water are used to impose temperature loading cycles on to the specimen. Accurate focussing of the line heaters using a two degree of freedom adjustment mechanism, enables a heating area of width 3 mm to be applied to the specimen. Both the heating and the cooling processes are controlled by a proportional, integral, and derivative feedback micro-processor controller. Specimen temperature fields are obtained using thermocouples, and specimen displacements and strains are measured using linear voltage displacement transducers and strain gauges.

A cyclic thermal loading test is carried out for approximately 7150 cycles on a model slag tap component. The variations of specimen strains and displacements are recorded and compared with results obtained from a finite element viscoplastic damage analysis. Good agreement between the predicted and experimental results is obtained.

Microstructural examination of the specimen reveals the development of persistent slip bands and micro-cracking at grain boundaries. This occurs at the regions of the specimen undergoing cyclic plasticity due to the imposed cyclic thermal loading.

The experimental observations of cyclic plasticity damage formation in copper undergoing cyclic thermal loading indicates the suitability of the Continuum Damage Mechanics (CDM) theory to model the evolution of cyclic plasticity damage. The damage is characterized by the development of fields of micro-cracked grain boundaries due to the formation and interaction of persistent slip bands within the grains.
Design sensitivity analysis using the boundary element method
Authors: Tafreshi A , Fenner R T
Published: July 2007

A directly differentiated form of boundary integral equation with respect to geometric design variables is used to calculate shape design sensitivities. This allows the coupling of an optimizing technique and a boundary element elastic stress analyser to form an optimum shape design algorithm in two dimensions. Hermitian cubic spline functions used to represent boundary shapes offer considerable advantages in fitting a wide range of curves, and in the automatic remeshing process. They also reduce the need for optimization constraints to avoid impractical designs during the optimization procedure. The boundary element method offers advantages over the finite element method, and is applicable to a wide range of shape optimization problems.
Acquisition and analysis of creep data
Authors: Wilshire B , Evans R W
Published: July 2007

The limitations of traditional methods of providing long-term creep design data are discussed in relation to existing national and international testing standards, current parametric procedures for extrapolation of stress-rupture values and the factors affecting the high degree of scatter in conventional long-term property sets for widely-used structural steels. These deficiencies may be overcome by adopting an alternative data acquisition methodology based on the analysis of short-term high-precision constant-stress creep curves.
Testing of full-size steam plant components
Authors: Coleman M C , Fidler R
Published: July 2007

The integrity of components operating in steam generating plant at elevated temperatures and pressures must be assured as they approach their design lives, of if they are found to contain defects. This paper describes a number of programmes that were undertaken by the Central Electricity Generating Board to ensure the continued safe operation of welded pipework components in such plant. The work described examines the behaviour of nominally sound and defective welded pipework as well as a specific case involving the testing of a component removed from fossil-fired plant. In each case, the results arising from the work are discussed in terms of the assessment and appraisals that may be applied to operating plant.
Analysis of fatigue strength on non-load-carrying and load-carrying fillet welded joints
Authors: Lie S T
Published: July 2007

An attempt has been made to study, theoretically, the difference in the fatigue behaviour of non-load-carrying and load-carrying fillet welded cruciform joints. In the former case, the pre-existing flaws produced during the welding process will always propagate from the weld toe. Accurate stress analysis using the boundary element method on the load-carrying fillet welded cruciform joints shows that the weld throat, h, should not be less than 1.414 T, or the weld leg length, w, should not be less than 2.0 T, where T is the main plate thickness, for the cracks to initiate from the weld toe. Furthermore, the values of Mk, the correction factor to take into account the presence of the weld, are found to decrease when the weld size is increased for the load-carrying fillet welded joints. The Paris crack propagation law is then computed numerically to obtain the S/N (signal-to-noise) curves for the two welded joints. The non-load-carrying fillet welded joints give 5 per cent higher fatigue life than the load-carrying ones for an applied stress range of 100 N/mm2.
A parametric study of the elastic stress distribution in pin-loaded lugs
Authors: Grant R J , Smart J , Stanley P
Published: July 2007

This paper describes a numerical study of the stress distribution in pin-loaded lugs. The effects of : (i) the ratio of lug width ( w) to hole diameter ( d), (ii) the ratio of the distance of the hole centre from the free end of the lug ( h) to hole diameter ( d), and (iii) the pin interference/clearance, on the magnitude and position of the maximum circumferential stress around the hole in the lug are established and discussed. Pin fit is shown to be a particularly important detail and the beneficial effects of an interference fit are shown to be considerable. It is also shown that for ratios w/d greater than 4 and h/d greater than 3 there is little variation in the maximum circumferential stress for a given applied load.
Fully plastic ductile tearing of HY130 steel—an analysis by J, COD, energy rate and crack opening angle
Authors: Dagbasi M , Turner C E
Published: July 2007

The dependence of J-R curves on size of test piece is examined for fully plastic deep notch bend (DNB) tests on HY130 steel, taken to large amounts of ductile crack growth (60 per cent of the ligament) for a range of initial widths at 20 mm thick and one geometrically similar size, 50 mm thick. The object is to understand the cause of the widely different patterns of behaviour that have been reported in the literature, even within the DNB type of configuration. In the present tests, the proportion of shear lip is the same for the geometrically similar pair but the J-R curve for the 50 mm thick piece is much lower than for the similar piece, 20 mm thick.

The rate of change of displacement, dq/da, is analysed using the factor. r∗, that defines the instantaneous centre of rotation at each step of growth, to give a measure of crack tip opening angle (CTOA), xg. After an initial transient regime of small growth, xg and r∗ remain constant. The normalized load. L, rises due to work hardening during crack growth by amounts that depend on size while xg and r∗ vary mildly with initial width to give an appreciable variation of the combined term Lxg/r∗, which is the factor that controls the behaviour of the JR curves. It is speculated that CTOA and its variation with configuration (as seen in the literature) may, for large growth, assume the role of the two parameters suggested in recent literature as controlling the variation of toughness with constraint.
Analytical and finite element predictions of residual stresses in cold worked fastener holes
Authors: Poussard C , Pavier M J , Smith D J
Published: July 2007

Two-dimensional finite element (FE) studies, for plane stress, plane strain and axisymmetric conditions, were conducted to simulate 4 per cent cold working of a 6.35 mm diameter hole in a 6 mm thick plate of 2024 T 351 aluminium alloy. The simulations were used to assess the influence of strain hardening, the role of reversed yielding and through-thickness residual stress distributions. Experiments were also conducted to determine the tensile and compressive stress-strain response of the aluminium alloy, revealing a pronounced Bauschinger effect and non-linear strain hardening in compression. The FE simulations and results from several earlier analytical models were compared and substantial differnces found in the region of reversed yielding. Approximations used to model the compressive deformation behaviour of the material overestimate the compressive residual stresses at the hole edge. From the axisymmetric FE model a residual stress gradient through the plate thickness was found. The plane stress and plane strain assumptions used in the earlier analytical models did not satisfactorily approximate the three-dimensional residual stress fields obtained from the FE simulations.
Stresses in a circular ring under two forces acting along a diameter
Authors: Batista M , Usenik J
Published: July 2007

This paper analyses the stress state in a circular ring under two opposite forces on its outer boundary. The solution is obtained by using the complex variable method and the principle of superposition. Stress concentration factors are calculated for the ratio of inner and outer radii in the range 0–0.95 and are presented in tabular form.
A geometrically versatile finite volume formulation for plane elastostatic stress analysis
Authors: Wheel M A
Published: July 2007

A finite volume formulation for discretizing and analysing plane elastostatic problems is described. Equilibrium equations which relate the displacements at the centre of a general quadrilateral cell to those in neighbouring cells are developed. After the application of suitable boundary conditions, an iterative method is employed to solve the resulting system of simultaneous equations and produce the displacement field, from which the strain and stress fields are derived subsequently. Stress distributions for a test problem, an elliptic plate pierced by an elliptic hole and loaded on the outer boundary, are determined for meshes of increasing refinement. The distributions are compared with those determined using triangular and quadrilateral finite elements and the analytical solution.
Phase-shifting methodologies in photoelastic analysis—the application of Jones calculus
Authors: Ramesh K , Ganapathy V
Published: July 2007

The potential of digital image processing hardware to record intensity data at video rates has resulted in a new approach for data collection. Efforts were aimed at evaluating isochromatic and isoclinic fringe orders quantitatively by processing the intensity data recorded. These methodologies have come to be known as phase-shifting techniques. The various phase-shifting algorithms in photoelasticity are surveyed and a comparative study is done. The use of Jones calculus to understand these methodologies is brought out. An attempt has been made to identify the reason for loss of accuracy in evaluating the field parameters in stress concentration zones.
Dynamic strain measurement using piezoelectric polymer film
Authors: Smith A L , Mee D J
Published: July 2007

Piezoelectric polymers have been used to form the basis of dynamic strain gauges for the detection of stress waves. The linearity of response was tested using a split Hopkinson pressure bar arrangement. The results obtained illustrate the effectiveness of piezoelectric film strain gauges in the measurement of axial stress waves.
The role of macroeconometric models in forecasting and policy analysis in the united states
Authors: McNees Stephen K.
Published: July 2007

This article stresses how little is known about the quality, particularly the relative quality, of macroeconometric models. Most economists make a strict distinction between the quality of a model per se and the accuracy of solutions based on that model. While this distinction is valid, it leaves unanswered how to compare the‘validity’of conditional models. The standard test, the accuracy of ex post simulations, is not definitive when models with differing degrees of exogeneity are compared. In addition, it is extremely difficult to estimate the relative quantitative importance of conceptual problems of models, such as parameter instability across‘policy regimes’

In light of the difficulty in comparisons of conditional macroeconometric models, many model‐builders and users assume that the best models are those that have been used to make the most accurate forecasts are those made with the best models. Forecasting experience indicates that forecasters using macroeconometric models have produced more accurate macroeconomic forecasts than either naive or sophisticated unconditional statistical models. It also suggests that judgementally adjusted forecasts have been more accurate than model‐based forecasts generated mechanically. The influence of econometrically‐based forecasts is now so pervasive that it is difficult to find examples of‘purely judgemental’forecasts.
Forecasting with an econometric model: The issue of judgemental adjustment
Authors: Young Richard M.
Published: July 2007

The paper outlines the current state of forecasting with an econometric model. After briefly distinguishing econometric techniques from other statistical approaches and arguing the advantages of this approach the paper concentrates on the issue of judgemental adjustments to models for forecasting purposes. Two types of adjustment are distinguished and the conditions under which each is justified are stated. Guidance in the use of adjustment is offered through a review of considerations in an actual forecasting situation.
The role of forecasting in corporate strategy: The xerox experience
Authors: Dino Richard N. , Riley Donald E. , Yatrakis Pan G.
Published: July 2007

This paper presents the system of analysis used by the Xerox Corporation to relate the external environment to company decisions. The system is sophisticated and elaborate, comes to grips with such issues as product forecasting, market monitoring, activity monitoring, materials and labour cost analysis, and product price analysis. In addition, the system examines the longer‐term issues associated with corporate strategy, with the more recent initiatives directed toward the strategic focus

The Xerox case illustrates very well how externally provided forecasts of economic environments, both at home and abroad, can be used as inputs to a variety of econometric products to serve the individual corporation. The challenge in this work is to build the bridges from the external forces to the critical company decisions. That is a task which requires sophisticated tools and skilled professionals to accomplish. This case study shows what can be done.
Aided and unaided decision making: Improving intuitive judgement
Authors: Sjöberg Lennart
Published: July 2007

Intuitive judgement forms the basis of decision making both by experts, in professional settings, and by people in everyday life. Psychologists have studied the rationality of intuitive judgements. In this paper three approaches to decision making will be discussed: unqualified rationalism, qualified rationalism and irrationalism. The first approach holds that man is essentially rational, the second that serious cognitive biases exist, and the third that thinking is strongly influenced by non‐cognitive sources of distortion, i.e. emotions and motives. Evidence on judgement is reviewed and found to support the last two approaches. Various ways of improving judgements, as suggested by the three basic viewpoints, are then presented.
Requirements for effective use of graphical methods in interactive forecasting
Authors: Polhemus Neil W.
Published: July 2007

The construction of forecasts using interactive data analysis systems is greatly aided by the availability of graphical procedures. Data exploration, model identification and estimation, and interpretation of final forecasts are made considerably easier by the visual relay of information. This article discusses some recent developments in time series graphics designed to assist in the forecasting process. A discussion of requirerients for effective use of graphics in interactive forecasting is included as illustrated through an application of the Box‐Jenkins methodology. Illustrations are included from the STATGRAPHICS system, a prototype implementation in APL.
Practitioners'Forum. Forecasting and Planning the Jeddah Air Traffic with a Mini Model
Authors: Karasek Mirek
Published: July 2007

A simple model of particular socio‐economic and technical environment proves useful in forecasting and planning. The specific application forecasts air traffic at King Abdulaziz International Airport (KAIA) in Jeddah, Saudi Arabia, through a number of explanatory variables

The purpose of the model is to explain and forecast the change in growth rates of passenger flow through the airport. The dynamics of passenger flow are linked to the dynamics of the oil‐based economy of Saudi Arabia and the global economic and business environment.
Forecasts and expectations: Some evidence for the U.K.
Authors: Holden K. , Peel D. A.
Published: July 2007

Forecasts from econometric models have been given a lot of publicity in the U.K. This paper examines the performance of five major models in forecasting inflation and the rate of growth. Two types of forecast are considered: the annual pre‐budget ones and a quarterly series. It is suggested that public forecasts provide a cheap method of implementing economically rational expectations.
An exploration of some practical issues in the use of quantitative forecasting models
Authors: Lawrence M. J.
Published: July 2007

Extrapolative forecasting models have been available for many years and as most organizations have the need to regularly develop forecasts one might anticipate the widespread use of these models. The evidence in Australia indicates that computer based forecasting systems are not being widely used and in fact a number of established systems have been discarded, with the issue of forecast accuracy often being mentioned as a problem area. Two experiments are carried out to examine this issue by comparing judgemental and quantitative forecasts. Other problem areas mentioned as contributing to the abandonment of forecasting systems include the difficulty of manually reviewing the computer forecasts and the effort required to carefully massage the forecast database to remove extraordinary events.
Familiarity, application, and performance of sales forecasting techniques
Authors: Mentzer John T. , Cox James E.
Published: July 2007

This article presents the results of a survey to determine the degree of familiarity and usage, accuracy obtained, and evaluation of different forecasting techniques. It was found that regression analysis, subjective techniques, exponential smoothing, and moving average were well known and used for specific situations. Accuracy was relatively high for aggregate short range forecasts, but decreased for longer range and product level forecasts.
Awareness and use of forecasting techniques in british industry
Authors: Sparkes John R. , McHugh A. K.
Published: July 2007

The paper summarizes results of a mail survey of the use of formal forecasting techniques in British manufacturing companies. It appraises the state of awareness of particular techniques and the extent to which they are used in various functional applications. The extent to which the forecasts generated by the techniques influence company action is assessed; and the reasons for the non‐use of particular techniques examined. The paper concludes that although an increasing number of companies appreciate the importance of forecasting, the methods used are predominantly naïve and few companies are taking steps to improve the situation through using alternative techniques or through computerizing established techniques.
Privatization, regulation and development: Some questions of training strategy
Authors: Collins Paul , Wallis Malcolm
Published: July 2007

In the current debate over the role of the public sector and its effective and efficient management, too little attention has been paid to the training implications of the various policy options. These include privatization as well as public enterprise performance improvement and rehabilitation. Third world training institutions are only just beginning to respond to the new tasks of re‐equipping public sector managers to enable them to play a more ‘enabling’ or ‘facilitating’ role vis‐à‐vis the private and parastatal sectors. Accordingly, this article suggests a number of major elements that need go into any national training effort to strengthen the government‐enterprise interface, including some of the curricular content, needs for case and teaching materials, developing training methods, the role of research, possibilities of a regional approach and the role of the international donor community.
District planning and local government in Kenya
Authors: Wallis Malcolm
Published: July 2007

In many ways the autonomy of local government in Kenya has declined in the last twenty years. After reviewing the various tendencies towards centralization which can be observed and looking at some of the reforms which have occurred, the current district planning approach, known as the District Focus for Rural Development Strategy, is analysed in order to explore the roles played within it by local government. Policy documents and other official statements are discussed, as are the attitudes of political and administrative leaders. Whilst the new strategy is supposed to bring about greater decentralization, it has led to a continuing reduction of local government autonomy especially for the county councils. However, pessimistic conclusions can not be easily drawn. Local government is not likely to be abolished, the new approach may enable it to play a more effective planning role—even if a less autonomous one—and there are other forms of local participation (especially through community development) which partly compensate for the erosion of formal local government.
The dilemma between mobilization and control in international aid the case of the Norwegian Sao Hill Sawmill project in Tanzania
Authors: Gran Thorvald
Published: July 2007

How do specific aid projects in Tanzania strike a balance between control and mobilization, between efficient implementation of a well defined project and the mobilization of a local learning and competence building process? Can the same project organization do both efficiently, or does the control‐mobilization relation represent a dilemma? And how do specific definitions of the balance between control and mobilization within projects affect state building locally? These questions are investigated in the context of the Sao Hill Sawmill (SHS) in Tanzania. The relationship between Tanzanian and Norwegian authorities is looked at (a) in the planning of the Mill, (b) in the early evaluations of it, and (c) in its first three years of operations. An attempt is made to show that decision models are both personally ‘constructed’ and systematically reproduced by institutions and that the distinction between control‐ and mobilization‐focused models is of importance for how projects affect local institution building. Whether persons were recruited to the project from private or public institutions in Norway influenced their understanding of what the project was about. The data suggest that this simple distinction is significant for understanding how projects relate to local institutions and development processes. The material indicates that experts from Norwegian public institutions supported a more mobilization‐oriented definition of the project, with the possibility of integrating it unobtrusively into existing local institutions. However, a surprise finding was that top‐level administration in Tanzania supported the private participants more control‐oriented definition.
The science of Javanese management: Organizational alignment in an Indonesian development programme
Authors: Useem Michael , Setti Louis , Pincus Jonathan
Published: July 2007

Studies of business organizations reveal the importance of combining two elements for mobilizing and aligning action in large organizations: informed decision making and contingent incentives. A national development programme in Indonesia tested both elements under exceptionally demanding conditions. The Government of Indonesia ended its subsidy of agricultural pesticides in the late 1980s, and it sought to prepare its large but poorly educated farming population in the use of ecologically based integrated pest management (IPM) methods. With a staff of 2,000 trainers by the early 1990s and a curriculum emphasizing information analysis and management decisions, the Indonesian national IPM programme created a capacity to train as many as 50,000 farmers per growing season. Field studies, trainee surveys and other evidence reveal that, consistent with national programme objectives, (1) pesticide applications were reduced by more than 60 per cent; (2) pesticide use depended more on field decisions, less on prescriptions; (3) small landholders were as likely as large holders to master IPM techniques; (4) IPM‐trained farmers experienced no loss in rice yield and significant savings in pesticide expense; (5) IPM‐trained farmers sought to share the new information and skills with other farmers. Together, informed decision making and contingent incentives provided the organizational foundation for a sustainable national change in agricultural methods.
Policy research in sub‐Saharan Africa: An exploration
Authors: Juma Calestous , Clark Norman
Published: July 2007

This article argues that a major problem with contemporary policy analysis is that it has difficulty coming to terms with complex economic change. This in turn is probably influenced by a view of socioeconomic systems that still harks back to the classical mechanics of the nineteenth century and a relatively stable world in which social action could reasonably be informed by disinterested scientific research of a traditional kind. By means of a review of some recent policy analysis literature and by focusing on issues relating to development issues in contemporary Africa, the article maintains that a more realistic approach would recognize the evolutionary nature of modern socioeconomic systems and base policy interventions accordingly. In particular, there is a need to see ‘policy’ as a process of complex change requiring innovative institutional contexts and novel managerial capabilities.
Electron‐Positron Pair Creation from Vacuum Induced by Variable Electric Field
Authors: Marinov M. S. , Popov V. S.
Published: July 2007

Problem is considered of spontaneous creation of electron‐positron paris from the vacuum induced by external electric field, that is homogeneous and depends on time in an arbitrary way. The Heisenberg equations of motion are obtained for the creation‐annihilation operators. The solution is a linear canonical transformation. The problem is reduced to a set of differential equations for the second‐order matrices determining this transformation. A consequence of the CP symmetry of the Dirac equation with an external electric field is that the e+e− pair is created from the vacuum in a state with total spin 1. The case when the variating electric field conserves its direction, is considered in more detail. In this case the equations are much simplified and may be reduced to the Riccati equation or to problem of oscillator with variable frequency, so the problem is equivalent to the one‐dimensional quantal problem of a barrier penetration. Two approximate methods to calculate the pair creation probabilities are discussed: the quasiclassical approach and the antiadiabatical method, applicable for sharp variations of the external field. Numerical estimates are obtained for the number of e+e− pairs produced by the field E(t) = E cos ωt. Group‐theoretical aspects of the problem are also considered.
Über die Bedeutung der Fouriertransformation für die optische Abbildung
Authors: Hofmann C.
Published: July 2007

Es wird gezeigt, daß die Fouriertransformation in guter Näherung die drei grundliegenden Aspekte der realen optischen Abbildung Beugung (exakt im Fraunhoferfall), Kohärenz des Lichtes und die Übertragungseigenschaften des optischen Systems beschreibt. Eine optische Abbildung kann in die beiden Schritte der Beugung am Objekt, die mathematisch durch die Fouriertransformation der Objektamplitudenverteilung in die Pupillenebene modelliert werden kann, und der Filterung und Beugung des Objektspektrums an der Pupille, die durch die inverse Fouriertransformation des beschnittenen Beugungsspektrums der Objektamplitudenverteilung von der Pupillen‐ in die Bildebene beschrieben werden kann, zerlegt werden. Die Anwendungsmöglichkeit dieser beiden Fourierschritte auf verschiedene optische Systeme wie Fouriertransformationsoptik, holographische Speicherung, Mikroskopoptik und Photoobjektive wird auf der Grundlage der Fouriertheorie der partiell kohärenten Abbildung diskutiert.
Collective Quantum Fields
Authors: Kleinert H.
Published: July 2007

A general quantum field theory of collective excitations is presented for many‐body systems. Lagrangians involving fundamental particles are transformed to collective fields exactly via Feynman path integrals. Graphically, this amounts to a complete resummation of the perturbation series without the danger of double counting. Plasma and pairing effects provide special examples corresponding to mutually complementary transformations. Bose and Fermi systems can be treated on equal footing. The methods are illustrated by giving the exact collective Lagrangian for the BCS model and approximate ones for type II superconductors and 3He.
On the Grand Canonical Gibbs Ensemble in Euclidean Field Theory
Authors: Gielerak R.
Published: July 2007

By generalizing the integration by parts formula on the function space, the isomorphism between the general class of selfinteracting Euclidean, Bose fields and classical gases is proven in a nonperturbative way. Rigorous, non‐perturbative derivations of the Mayer equations and Bogoliubov‐Born‐Kirkwood‐Grenn‐Yvone hierarchical equations are given. Expansions of several physical quantities are discussed in terms of the linear graphs, for some general classes of Euclidean fields.
Superspinors and Graded Lorentz Groups in Three, Four and Five Dimensions
Authors: Lukierski J. , Nowicki A.
Published: July 2007

Three superalgebras osp(1; 2; F) (F = R, C, H) and corresponding three supergroups are considered. The transformation laws of spinors with anticommuting components for 3‐dimensional (O(2, 1) ≃ Sp(2; R)), 4‐dimensional (O(3, 1) ≃ Sp(2, C)) and 5‐dimensional (O(4, 1) ≃ Sp(2; H)) Lorentz group are extended in a supersymmetric way by introducing nonlinear realizations of the supergroups OSp(1, 2; F). The affine Grassmann spinors in all three cases are obtained by suitable “flat” limit of the nonlinear realization. Different gradings and different contractions of osp(1,2; F) (F = R, C, H) superalgebras are considered.
The dynamic histogram chart
Authors: Holmes Donald S. , Mergen A. Erhan
Published: July 2007

This paper discusses a dynamic histogram control chart which combines some ideas of histograms, X charts, zone charts and chi‐square charts. The chart is easy to use, easy to understand, and has quick response times. Another feature is that it does not require normal data as X charts and zone charts do. The chart is especially useful for controlling processes with low data accumulation rates such as chemical processes or for controlling processes involving short runs such as job shops.
Mapping quality assurance systems: A methodology
Authors: Crossfield R. T. , Dale B. G.
Published: July 2007

This paper reports on a method (quality management activity planning—Q‐MAP) for mapping quality assurance procedures, information flows and responsibilities. A comparison is made of the ICAM definition (IDEF) method and Q‐MAP as to their suitability for mapping quality assurance systems and fostering the advancement of the quality improvement process. The achievements arising from the use of Q‐MAP at Garrett Automotive Limited are examined. It is pointed out that the involvement of employees in the preparation of Q‐MAP diagrams has led to improvements in processes and procedures by eliminating differences between actual and documented work practices and that a wider cross‐section of employees are now familiar with the company's quality assurance system.
An analysis of the field failure of passive and active components
Authors: Campbell D. S. , Hayes J. A.
Published: July 2007

This paper briefly describes work that is in hand on establishing and running an organization for the collection and analysis of field failure data on passive and active components in electronic equipment. Data have now been collected from all the sources for nearly two and a half years as of June 1989 and the results obtained are presented. Analysis covers a wide range of electronic component categories.
Temperature–humidity induced mechanisms in plastic encapsulated bipolar transistors
Authors: Matthäi Günter
Published: July 2007

In this article the disadvantages of well‐known models for temperature–humidity induced failure mechanisms in plastic encapsulated microelectronic devices are shown. It is necessary to restrict the validity of these models. The advantage of bipolar transistors is that the failure mechanisms can be separated very easily. The most significant properties of polymers, plastication and glass transition, and also the diffusion of moisture will be described. The hydrolysis of chlorides is considered with respect to processes of polymeric physics and it is shown that chlorides form electrolytic distances and etchant inside the transistors. In this case the microelectronic devices change their electric characteristics and sometimes the electrical connection is interrupted. The model shows that the aggressiveness of the resin is affected by temperature and humidity and also how this aggressiveness affects the transistor. This model combines the mechanisms in the resin with the reactions of the devices. It provides a good basis for improving the reliability of microelectronic devices and for designing proper reliability tests.
Quality assurance of welds in ship structures
Authors: Stavrakakis G. S.
Published: July 2007

This paper describes procedures for predicting the growth rate of fatigue cracks in ship structure welds under sea‐wave loading as well as the stress corrosion cracking behaviour of steel in marine structures. A computer program which can be applied to assess the residual life‐time and to estimate the probability of failure of marine structures under wave action is presented. The main objective of applying this program is the development of an optimal inspection and maintenance policy for marine structures. Moreover, the presented computer program is of value to insurance companies in order to assess the safety level of a marine structure and consequently to estimate their financial risk.
The balance chart: A new SPC Concept
Authors: Thomas D. E.
Published: July 2007

This paper outlines a new technique of statistical process control which goes a considerable way to resolving several existing problems. The technique described may be of particular value to automated control, small batch control and control of gauged processes. A new charting technique is described and compared with traditional control charts. The operation of the balance chart is outlined for attribute and variable processes and in precontrol mode. A graphical system for determining estimated Cp, Cpk and process mean values from limited process data is also included.