Micro-milling work-holding devices employing adhesive forces

IngenieursweseBedryfsingenieursweseMicro-parts are often very fragile rendering conventional, mechanical work-holding fixtures unsuitable for them since they exert large straining forces. Furthermore, macroworkholding devices occupy a large space which impedes high precision required in micromilling. Although some micro-clamping fixtures exist, they are limited to specific part shapes and in most cases expensive to manufacture. Hence this paper focuses on the application of adhesive forces namely electrostatic, surface tension and van-der-Waals forces; in work-holding strategies for micro-milling operations. An analysis is given as to their applicability with reference to micro-milling cutting forces

Macroeconomic drivers affecting the foundry industry in South Africa

Background: The problem addressed in the study reported on in this article is the decline of South Africa’s foundry industry. This industry is valuable in terms of job creation and a sustainable competitive advantage (SCA) strategy is required to sustain the industry in South Africa. Aim: With the dearth of research on sustainability of the foundry industry, the research comprised three objectives; namely, to identify from literature the macroeconomic drivers, to empirically identify critical macroeconomic drivers, and to make recommendations on strategies for enhancing SCA for foundries in South Africa. Setting: The study was conducted during 2022 within the foundry industry in South Africa. Foundry representatives from foundries located in all nine provinces of South Africa were invited to participate in the study. Method: The study adopted an explanatory sequential mixed-methods methodology, initially employing a quantitative approach, and subsequently applying a qualitative approach to ascertain the most influential macroeconomic drivers. Quantitative data analysis entailed descriptive methods, while the qualitative phase involved thematic analysis. Conclusion: The study contributes by identifying the macroeconomic drivers that can be used by industry leaders in the formulation of strategies for SCA within the African context. Contribution: The study contributes by identifying the macroeconomic drivers that can be used by industry leaders in the formulation of strategies for SCA

Constrained dogleg methods for nonlinear systems with simple bounds

We focus on the numerical solution of medium scale bound-constrained systems of nonlinear equations. In this context, we consider an affine-scaling trust region approach that allows a great flexibility in choosing the scaling matrix used to handle the bounds. The method is based on a dogleg procedure tailored for constrained problems and so, it is named Constrained Dogleg method. It generates only strictly feasible iterates. Global and locally fast convergence is ensured under standard assumptions. The method has been implemented in the Matlab solver CoDoSol that supports several diagonal scalings in both spherical and elliptical trust region frameworks. We give a brief account of CoDoSol and report on the computational experience performed on a number of representative test problem

Green Tax Reform, Endogenous Innovation and the Growth Dividend

We study theoretically and numerically the effects of an environmental tax reform using endogenous growth theory. In the theoretical part, mobile labor between manufacturing and R&D activities, and elasticity of substitution between labor and energy in manufacturing lower than unity allow for a growth dividend, even if we consider preexisting tax distortions. The scope for innovation is reduced when we consider direct financial investment in the lab, or elastic labor supply. We then apply the core theoretical model to a real growing economy and find that a boost in economic growth following such a carbon policy is a possible outcome. Lump-sum redistribution performs best in terms of effciency measured by aggregate welfare, while in terms of equity among social segments its progressive character fails when we consider very high emissions reduction targets

What do clinicians want? Interest in integrative health services at a North Carolina academic medical center

BACKGROUND: Use of complementary medicine is common, consumer driven and usually outpatient focused. We wished to determine interest among the medical staff at a North Carolina academic medical center in integrating diverse therapies and services into comprehensive care. METHODS: We conducted a cross sectional on-line survey of physicians, nurse practitioners and physician assistants at a tertiary care medical center in 2006. The survey contained questions on referrals and recommendations in the past year and interest in therapies or services if they were to be provided at the medical center in the future. RESULTS: Responses were received from 173 clinicians in 26 different departments, programs and centers. There was strong interest in offering several specific therapies: therapeutic exercise (77%), expert consultation about herbs and dietary supplements (69%), and massage (66%); there was even stronger interest in offering comprehensive treatment programs such as multidisciplinary pain management (84%), comprehensive nutritional assessment and advice (84%), obesity/healthy lifestyle promotion (80%), fit for life (exercise and lifestyle program, 76%), diabetes healthy lifestyle promotion (73%); and comprehensive psychological services for stress management, including hypnosis and biofeedback (73%). CONCLUSION: There is strong interest among medical staff at an academic health center in comprehensive, integrated services for pain, obesity, and diabetes and in specific services in fitness, nutrition and stress management. Future studies will need to assess the cost-effectiveness of such services, as well as their financial sustainability and impact on patient satisfaction, health and quality of life

OPTIMIZATION WITH LINEAR COMPLEMENTARITY CONSTRAINTS

A Mathematical Program with Linear Complementarity Constraints (MPLCC) is an optimization problem where a continuously differentiable function is minimized on a set defined by linear constraints and complementarity conditions on pairs of complementary variables. This problem finds many applications in several areas of science, engineering and economics and is also an important tool for the solution of some NP-hard structured and nonconvex optimization problems, such as bilevel, bilinear and nonconvex quadratic programs and the eigenvalue complementarity problem. In this paper some of the most relevant applications of the MPLCC and formulations of nonconvex optimization problems as MPLCCs are first presented. Algorithms for computing a feasible solution, a stationary point and a global minimum for the MPLCC are next discussed. The most important nonlinear programming methods, complementarity algorithms, enumerative techniques and 0 - 1 integer programming approaches for the MPLCC are reviewed. Some comments about the computational performance of these algorithms and a few topics for future research are also included in this survey