19,738 research outputs found
The Unresolved Tension Between Trademark Protection and Free Movement of Goods in the European Community
Developments in computer-aided engineering and the rapid growth of computational power have made simulation-driven process and product development efficient and useful since it enables detailed evaluation of product designs and their manufacturing processes. In the context of a sheet metal component, it is vital to predict possible failure both during its forming process and its subsequent usage. Accurate numerical models are needed in order to obtain trustworthy simulation results. Furthermore, the increasing demands imposed on improved weight-to-performance ratio for many products endorse the use of high-strength steels. These steels often show anisotropic behaviour and more complex hardening and fracturing compared to conventional steels. Consequently, demand for research on material and failure models suitable for these steels has increased. In this work, the mechanical and fracture behaviour of two high-strength steels, Docol 600DP and Docol 1200M, have been studied under various deformation processes. Experimental results have been used both for material characterisation and for calibration of fracture criteria. One major requirement as concerns the fracture criteria studied is that they should be simple to apply in industrial applications, i.e. it should be possible to easily calibrate the fracture criteria in simple mechanical experiments and they should be efficient and accurate. Consequently, un-coupled phenomenological damage models have been the main focus throughout this work. Detailed finite element models including accurate constitutive laws have be used to predict and capture material instabilities. Most of the fracture criteria studied are modifications of the plastic work to fracture. Ductile tensile and ductile shear types of fracture are of particular interest in sheet metal applications. For these fractures the modification of the plastic work relates to void coalescence and void collapse, respectively. Anisotropy in fracture behaviour can be captured by the introduction of a material directional function. The dissertation consists of two parts. The first part contains theory and background. The second consists of five papers
Comparable-Worth Wage Adjustments and Female Employment in the State and Local Sector
Our paper simulates the likely effects of a comparable-worth wage-adjustment policy in the state and local sector on female employment in the sector. The simulation is based on estimates of within-occupation male/female substitution and across-occupation occupational employment substitution that we obtain using data from the 1980 Census of Population
Comparable Worth in the Public Sector
Proponents of comparable worth assert that within a firm jobs can be valued in terms of the skill, effort and responsibility they require, as well as the working conditions they offer, and that jobs that are of comparable worth to the firm should receive equal compensation. After documenting the major push that has occurred for comparable worth in the state and local sector, Section II of our paper discusses the case for and against comparable worth from the perspective of analystical economists.The reminder of the paper is empirical in nature and focuses on issues that arise when one attempts to implement comparable worth. Section III addresses attempts by various states to infer if comparable worth "wage gaps" exist from job evaluation studies they have conducted and tests how sensitive their results are to the statistical methods used to infer discrimination. Section IV estimates whether male/female comparable worth wage gaps nay partially be compensating differentials for differences in opportunity for occupational nobility. Finally Section V presents estimates of systems of demand curves for state and local government employees and tests whether within occupational groups male/female substitution occurs as male/female wage rates change and whether substitution occurs across occupations as occupational wages change. These estimates are then used to simulate what the likely effect of a comparable worth wage policy would be on employment of females in the state and local sector.
Estimating Wage-Fringe Trade-Offs: Some Data Problems
Our paper attempts to identify the types of data nee3ed to estimate tradeoffs between wages and fringe benefits (such as pensions); it also explores the usefulness for this estimation of one particular employer- based data set collected by gay Associates. We stress three things: first, that employer-based data sets are required. Second, because pensions and many other fringe benefits are actuarial functions of wages or salaries, these technical relationships must be accounted for in estimation. Third, to take account of unobservable heterogeneity of employees across employers, one must use econometric methods that control for these unobservable variables. The paper concludes with a discussion of our attempts to estimate the tradeoff between wages and fringe benefits using a unique database for 200 establishments that contains information on wages and actuarial valuations of employer costs of fringe benefits at three different job levels.
Width and Magnetic Field Dependence of Transition Temperature in Ultranarrow Superconducting Wires
We calculate the transition temperature in ultranarrow superconducting wires
as a function of wire width, resistance and applied magnetic field. We compare
the results of first-order perturbation theory and the non-perturbative
resummation technique developed by Oreg and Finkel'stein. The latter technique
is found to be superior as it is valid even in the strong disorder limit. In
both cases the predicted additional suppression of the transition temperature
due to the reduced dimensionality is strongly dependent upon the boundary
conditions used. When we use the correct (zero-gradient) boundary conditions,
we find that theory and experiment are consistent, although more experimental
data is required to verify this systematically. We calculate the magnetic field
dependence of the transition temperature for different wire widths and
resistances in the hope that this will be measured in future experiments. The
predicted results have a rich structure - in particular we find a dimensional
crossover which can be tuned by varying either the width of the wire or its
resistance per square.Comment: 12 pages, 1 table, 7 figures. The changes made to the paper are ones
of emphasis. The comparison between theory and experiment has been altered,
and detailed comparisons of various approximations have been omitted,
although the results are summarised in the paper. Much more emphasis has been
placed on the new predictions of the effect of an applied magnetic field on
transition temperature in wires (Figs. 5-7
Calibration of the visible and near-infrared channels of the NOAA-9 AVHRR using high-altitude aircraft measurements from August 1985 and October 1986
Visible and near infrared wavelength sensors mounted on operational satellites now in use do not have onboard absolute calibration devices. One means of establishing an in-orbit calibration for a satellite sensor is to make simultaneous measurement of a bright, relatively uniform scene along the satellite view vector from a calibrated instrument on board a high altitude aircraft. Herein, aircraft data were recorded over White Sands, New Mexico at satellite overpass time. Comparison of the coincident aircraft and orbiting satellite data for the visible and near infrared wavelength channels of the NOAA-9 Advanced Very High Resolution Radiometer shows that the calibration of the visible channel was unchanged from prelaunch values, but that the near infrared channel has degraded 6 percent by Aug. 1985. By Oct. 1986 the visible channel had degraded 13 percent and the near infrared channel had degraded 19 percent
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