443 research outputs found

    Design Optimization for an Electro-Thermally Actuated Polymeric Microgripper

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    Thermal micro-actuators are a promising solution to the need for large-displacement, gentle handling force, low-power MEMS actuators. Potential applications of these devices are micro-relays, assembling and miniature medical instrumentation. In this paper the development of thermal microactuators based on SU-8 polymer is described. The paper presents the development of a new microgripper which can realize a movement of the gripping arms with possibility for positioning and manipulating of the gripped object. Two models of polymeric microgripper electrothermo- mechanical actuated, using low actuation voltages, designed for SU-8 polymer fabrication were presented. The electro-thermal microgrippers were designed and optimized using finite element simulations. Electro-thermo-mechanical simulations based on finite element method were performed for each of the model in order to compare the results. Preliminary experimental tests were carried out.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/16838

    Analytical results regarding electrostatic resonances of surface phonon/plasmon polaritons: separation of variables with a twist

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    The boundary integral equation method ascertains explicit relations between localized surface phonon and plasmon polariton resonances and the eigenvalues of its associated electrostatic operator. We show that group-theoretical analysis of Laplace equation can be used to calculate the full set of eigenvalues and eigenfunctions of the electrostatic operator for shapes and shells described by separable coordinate systems. These results not only unify and generalize many existing studies but also offer the opportunity to expand the study of phenomena like cloaking by anomalous localized resonance. For that reason we calculate the eigenvalues and eigenfunctions of elliptic and circular cylinders. We illustrate the benefits of using the boundary integral equation method to interpret recent experiments involving localized surface phonon polariton resonances and the size scaling of plasmon resonances in graphene nano-disks. Finally, symmetry-based operator analysis can be extended from electrostatic to full-wave regime. Thus, bound states of light in the continuum can be studied for shapes beyond spherical configurations.Comment: 25 pages, 3 figures, to be published Proc. Royal Soc.

    The production deployment of IPv6 on WLCG

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    The world is rapidly running out of IPv4 addresses; the number of IPv6 end systems connected to the internet is increasing; WLCG and the LHC experiments may soon have access to worker nodes and/or virtual machines (VMs) possessing only an IPv6 routable address. The HEPiX IPv6 Working Group has been investigating, testing and planning for dual-stack services on WLCG for several years. Following feedback from our working group, many of the storage technologies in use on WLCG have recently been made IPv6-capable. This paper presents the IPv6 requirements, tests and plans of the LHC experiments together with the tests performed on the group's IPv6 test-bed. This is primarily aimed at IPv6-only worker nodes or VMs accessing several different implementations of a global dual-stack federated storage service. Finally the plans for deployment of production dual-stack WLCG services are presented

    The effect of the timing and spacing of births on the level of labor market involvement of married women

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    We use panel data from NLSY79 to analyze the effects of the timing and spacing of births on the labor supply of married women in a framework that accounts for the endogeneity of labor market and fertility decisions, the heterogeneity of the effects of children and their correlation with the fertility decisions, and the correlation of sequential labor market decisions. Our results show that timing and spacing of births are important determinants of the effect of children on women's labor supply. Delaying the first birth leads to higher levels of labor market involvement before the birth of the first child and reduces the negative effect of the first child on the level of labor market involvement. Having the second birth after a longer interval reduces the effect of the second child on participation but increases its effect on the probability of working full time, as more women, having returned to work, respond to the second birth by moving from full time to part time jobs. Individual heterogeneity plays an important role in the relationship between labor market and fertility decisions. Women who have fewer children have the first birth later in life and space subsequent births more closely together, work more before the birth of the first child, but face larger effects of children on their labor supply

    The effect of children on the level of labor market involvement of married women: what is the role of education?

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    We analyze the way women's education influences the effect of children on their level of labor market involvement. We propose an econometric model that accounts for the endogeneity of labor market and fertility decisions, for the heterogeneity of the effects of children and their correlation with the fertility decisions, and for the correlation of sequential labor market decisions. We estimate the model using panel data from NLSY79. Our results show that women with higher education work more before the birth of the first child, but children have larger negative effects on their level of labor market involvement. Differences across education levels are more pronounced with respect to full time employment than with respect to participation. Other things equal, higher wages reduce the effect of children on labor supply. Controlling for wages, women with higher education face larger negative effects of children on labor supply, which suggest they are characterized by a combination of higher marginal product of time spent in the production of child quality and higher marginal product of time relative to the marginal product of other inputs into the production of child quality

    A panel data analysis of racial/ethnic differences in married women's labor supply

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    We study differences in life-cycle labor supply among white, black, and Hispanic women, focusing on the interaction between race/ethnicity, education, and fertility. We use panel data that capture women's labor market and fertility histories and an econometric model that accounts for the endogeneity of labor market and fertility decisions, the heterogeneity of the effects of children and their correlation with the fertility decisions, and the correlation of sequential labor market decisions. Our results show an intricate connection between race/ethnicity, education, and fertility as determinants of women's life-cycle labor supply. For all levels of education, white women have fewer children, have the first birth later in life, and space subsequent births more closely together. The level of labor market involvement before the first birth is highest for white women and lowest for Hispanic women, but children reverse the relationship between race/ethnicity and level of labor market involvement. The negative effects of children are largest for white women and smallest for Hispanic women, and as a result, among women with two children, black and Hispanic women work more than white women. Racial/ethnic differences in fertility decisions, pre-natal labor supply, and labor supply responsiveness to children decline with the level education. Educational differences contribute to the racial/ethnic differentials in labor supply. White women have the highest levels of education and Hispanic women have the lowest levels of education. Other things equal, women with higher education have fewer children, have the first birth later in life, space subsequent births more closely together, work more before the birth of the first child, but face larger negative effects of children on their level of labor market involvement

    MonALISA : A Distributed Monitoring Service Architecture

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    The MonALISA (Monitoring Agents in A Large Integrated Services Architecture) system provides a distributed monitoring service. MonALISA is based on a scalable Dynamic Distributed Services Architecture which is designed to meet the needs of physics collaborations for monitoring global Grid systems, and is implemented using JINI/JAVA and WSDL/SOAP technologies. The scalability of the system derives from the use of multithreaded Station Servers to host a variety of loosely coupled self-describing dynamic services, the ability of each service to register itself and then to be discovered and used by any other services, or clients that require such information, and the ability of all services and clients subscribing to a set of events (state changes) in the system to be notified automatically. The framework integrates several existing monitoring tools and procedures to collect parameters describing computational nodes, applications and network performance. It has built-in SNMP support and network-performance monitoring algorithms that enable it to monitor end-to-end network performance as well as the performance and state of site facilities in a Grid. MonALISA is currently running around the clock on the US CMS test Grid as well as an increasing number of other sites. It is also being used to monitor the performance and optimize the interconnections among the reflectors in the VRVS system.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 8 pages, pdf. PSN MOET00

    Joint Estimation of Sequential Labor Force Participation and Fertility Decisions Using Markov Chain Monte Carlo Techniques

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    In this paper we estimate the causal effect of children on the labor supply of women using panel data on women from the 1979 National Longitudinal Survey of Youth (NLSY79). We examine the effect of children both prior to and after birth as well as how the effect of children varies with the number of children. We also decompose the total effect of children into the direct and indirect components and separately examine the dynamics of these components. Sequential participation decisions for four levels of labor market involvement and fertility decisions are jointly modeled. We allow decisions to be correlated in a general fashion both across time and across choices. The estimation is performed using Markov chain Monte Carlo methods. We find that children have a strong effect on a women's labor market behavior in the post-birth period and that differences in expected fertility have a strang effect on labor market behavior in the pre-birth period. We also find that both the direct and indirect effects are large immediately after the birth of a child but that the indirect effect declines quickly over time. The effects of children vary by education and race
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