4,246 research outputs found

    Analytical And Experimental Investigation On Vibration Control Of Piezoelectric Structures

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    Active vibration control of smart structural materials (beam and plate) has been achieved by using distributed piezoelectric actuators. Numerical simulation and experimental testing have been conducted to investigate vibration suppression of the advanced structures. Results from simulation and testing are in satisfactory agreement

    Exposing errors related to weak memory in GPU applications

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    © 2016 ACM.We present the systematic design of a testing environment that uses stressing and fuzzing to reveal errors in GPU applications that arise due to weak memory effects. We evaluate our approach on seven GPUS spanning three NVIDIA architectures, across ten CUDA applications that use fine-grained concurrency. Our results show that applications that rarely or never exhibit errors related to weak memory when executed natively can readily exhibit these errors when executed in our testing environment. Our testing environment also provides a means to help identify the root causes of such errors, and automatically suggests how to insert fences that harden an application against weak memory bugs. To understand the cost of GPU fences, we benchmark applications with fences provided by the hardening strategy as well as a more conservative, sound fencing strategy

    Uniform tiling with electrical resistors

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    The electric resistance between two arbitrary nodes on any infinite lattice structure of resistors that is a periodic tiling of space is obtained. Our general approach is based on the lattice Green's function of the Laplacian matrix associated with the network. We present several non-trivial examples to show how efficient our method is. Deriving explicit resistance formulas it is shown that the Kagom\'e, the diced and the decorated lattice can be mapped to the triangular and square lattice of resistors. Our work can be extended to the random walk problem or to electron dynamics in condensed matter physics.Comment: 22 pages, 14 figure

    Remarks on NonHamiltonian Statistical Mechanics: Lyapunov Exponents and Phase-Space Dimensionality Loss

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    The dissipation associated with nonequilibrium flow processes is reflected by the formation of strange attractor distributions in phase space. The information dimension of these attractors is less than that of the equilibrium phase space, corresponding to the extreme rarity of nonequilibrium states. Here we take advantage of a simple model for heat conduction to demonstrate that the nonequilibrium dimensionality loss can definitely exceed the number of phase-space dimensions required to thermostat an otherwise Hamiltonian system.Comment: 5 pages, 2 figures, minor typos correcte

    Suppression of core polarization in halo nuclei

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    We present a microscopic study of halo nuclei, starting from the Paris and Bonn potentials and employing a two-frequency shell model approach. It is found that the core-polarization effect is dramatically suppressed in such nuclei. Consequently the effective interaction for halo nucleons is almost entirely given by the bare G-matrix alone, which presently can be evaluated with a high degree of accuracy. The experimental pairing energies between the two halo neutrons in 6^6He and 11^{11}Li nuclei are satisfactorily reproduced by our calculation. It is suggested that the fundamental nucleon-nucleon interaction can be probed in a clearer and more direct way in halo nuclei than in ordinary nuclei.Comment: 11 pages, RevTex, 2 postscript figures; major revisions, matches version to appear in Phys. Rev. Letter

    A Multicriteria Analysis on the Strategies to Open Taiwan's Mobile Virtual Network Operators Services

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    [[abstract]]This study investigates the trends followed by MVNOs (Mobile Virtual Network Operators) in the last three years and analyzes the strategies that can contribute to the success of Taiwan's telecommunications industry and marketing. We apply the method and concept of PATTERN (Planning Assistance Through Technical Evaluation of Relevance Number) to establish relevant systems for searching out the key successful factors of strategies to attract MVNOs. We also use the fuzzy Multi-Criteria Decision Making (MCDM) method for analyzing the different preference of a decision group in the criteria weights and for ranking the alternatives in a fuzzy environment in order to provide a strategy scheme. These results provide a reference to assist telecommunications operators, 3G license owners, potential MVNOs, and equipment manufacturers when working out business plans.[[incitationindex]]SCI[[booktype]]箙

    Controlled, pulsatile release of thermostabilized inactivated polio vaccine from PLGA-based microspheres

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    Many vaccines, such as the inactivated polio vaccine (IPV), must be administered in several doses for full efficacy. Because patient access is a major challenge for vaccination efforts in developing countries, administering multiple doses per patient is impractical in those areas. Single-administration vaccines would greatly improve efforts to vaccinate populations in Third World countries, and the World Health Organization (WHO) Expanded Program for Immunization describes an ideal vaccine as one that is heat-stable, requires only one shot, and is easy to administer. Although already existing technologies, such as microspheres composed of poly(lactic-co-glycolic acid) (PLGA), are able to encapsulate vaccines and release them over an extended period of time up to several weeks, they are not able to maintain antigen stability over the longer time intervals in vivo. Vaccines such as IPV, however, are known to be unstable at elevated temperature, such as the 37°C environment of the body, as well as in the acidic environment of the degrading PLGA microspheres. Please click Additional Files below to see the full abstract

    Angular Dependences of Third Harmonic Generation from Microdroplets

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    We present experimental and theoretical results for the angular dependence of third harmonic generation (THG) of water droplets in the micrometer range (size parameter 62<ka<24862<ka<248). The THG signal in pp- and ss-polarization obtained with ultrashort laser pulses is compared with a recently developed nonlinear extension of classical Mie theory including multipoles of order l≀250l\leq250. Both theory and experiment yield over a wide range of size parameters remarkably stable intensity maxima close to the forward and backward direction at ``magic angles''. In contrast to linear Mie scattering, both are of comparable intensity.Comment: 4 pages, RevTeX, 3 figures available on request from [email protected], submitted to PR

    Thermostabilization of inactivated polio vaccine in PLGA-based microspheres for pulsatile release

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    AbstractVaccines are a critical clinical tool in preventing illness and death due to infectious diseases and are regularly administered to children and adults across the globe. In order to obtain full protection from many vaccines, an individual needs to receive multiple doses over the course of months. However, vaccine administration in developing countries is limited by the difficulty in consistently delivering a second or third dose, and some vaccines, including the inactivated polio vaccine (IPV), must be injected more than once for efficacy. In addition, IPV does not remain stable over time at elevated temperatures, such as those it would encounter over time in the body if it were to be injected as a single-administration vaccine. In this manuscript, we describe microspheres composed of poly(lactic-co-glycolic acid) (PLGA) that can encapsulate IPV along with stabilizing excipients and release immunogenic IPV over the course of several weeks. Additionally, pH-sensitive, cationic dopants such as Eudragit E polymer caused clinically relevant amounts of stable IPV release upon degradation of the PLGA matrix. Specifically, IPV was released in two separate bursts, mimicking the delivery of two boluses approximately one month apart. In one of our top formulations, 1.4, 1.1, and 1.2 doses of the IPV serotype 1, 2, and 3, respectively, were released within the first few days from 50mg of particles. During the delayed, second burst, 0.5, 0.8, and 0.6 doses of each serotype, respectively, were released; thus, 50mg of these particles released approximately two clinical doses spaced a month apart. Immunization of rats with the leading microsphere formulation showed more robust and long-lasting humoral immune response compared to a single bolus injection and was statistically non-inferior from two bolus injections spaced 1 month apart. By minimizing the number of administrations of a vaccine, such as IPV, this technology can serve as a tool to aid in the eradication of polio and other infectious diseases for the improvement of global health
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