27,463 research outputs found

    Advanced Solar Power Systems

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    The Advanced Solar Power System (ASPS) concentrator uses a technically sophisticated design and extensive tooling to produce very efficient (80 to 90%) and versatile energy supply equipment which is inexpensive to manufacture and requires little maintenance. The advanced optical design has two 10th order, generalized aspheric surfaces in a Cassegrainian configuration which gives outstanding performance and is relatively insensitive to temperature changes and wind loading. Manufacturing tolerances also have been achieved. The key to the ASPS is the direct absorption of concentrated sunlight in the working fluid by radiative transfers in a black body cavity. The basic ASPS design concepts, efficiency, optical system, and tracking and focusing controls are described

    The use of function points to find cost analogies

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    Finding effective techniques for the early estimation of project effort remains an important — and frustratingly elusive — research objective for the software development community. We have conducted an empirical study of 21 real time projects for a major software developer. The study collected a range of counts and measures derived from specification documents, including a derivative of Function Points intended for highly constrained systems. Notwithstanding the fact that the projects were drawn from a comparatively stable environment, traditional approaches for building prediction systems, (for example, regression analysis) failed to yield a useful predictive model. By contrast, estimation based upon the automated search for analogous projects produced more accurate estimates. How much this is a characteristic of this particular dataset and how much these findings might be more generally replicated is uncertain. Nevertheless, these results should act as encouragement for follow up research on a much under utilised estimation technique

    The EMC of satellite power systems and DoD C-E systems

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    The solar power satellite (SPS) technical parameters that are needed to accurately assess the electromagnetic compatibility (EMC) between SPS systems and DoD communications-electronics (C-E) systems are identified and assessed. The type of electromagnetic interactions that could degrade the performance of C-E systems are described and the major military installations in the southwestern portions of CONUS where specially sensitive C-E systems are being used for combat training and evaluation are identified. Classes of C-E systems that are generally in the vicinity of these military installations are considered. The Technical parameters that govern the degree of compatibility of the SPS with these C-E systems, and some technical requirements that are necessary to ensure short-term and long-term EMC are identified

    Navigating the Labor Market in China: Enhancing Expatriate Effectiveness

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    [Excerpt] As business continues to grow in China, employers there struggle to find locals who possess the needed knowledge, skills, and abilities to meet the talent demands of the market. Many multinational corporations fill requisitions with candidates from outside of their local region or even from outside China. Since expatriate assignments are extremely costly, employers actively seek cost-effective expatriate compensation options. The local-plus-pay approach in China is popular but remains a work-in-progress. In addition to lower-cost compensation and benefit plans, employers are searching for increased return on expatriate investment. In fact, 10 to 20 percent of all U.S. managers sent abroad returned early because of job dissatisfaction or difficulties in adjusting to a foreign country. Of those who stayed for the duration, nearly one-third performed below satisfaction. Most alarming, one-fourth of repatriated employees joined a competitor within one year of returning to their home country. This paper discusses the complexities HR professionals face in China including attracting top talent into an organization—with a focus on expatriates—and in managing an organization uniquely situated in a high-growth environment. It further highlights successful best practices to thrive in such circumstances

    Use of synchrotron tomographic techniques in the assessment of diffusion parameters for solute transport in groundwater flow

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    This technical note describes the use of time-resolved synchrotron radiation tomographic energy dispersive diffraction imaging (TEDDI) and tomographic X-ray fluorescence (TXRF) for examining ion diffusion in porous media. The technique is capable of tracking the diffusion of several ion species simultaneously. This is illustrated by results which compare the movement of Cs+, Ba2+ and La3+ ions from solution into a typical sample of English chalk. The results exhibited somewhat anomalous (non-Fickian) behaviour and revealed heterogeneities (in 1D) on the scale of a few millimetres

    Robustness of the nodal d-wave spectrum to strongly fluctuating competing order

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    We resolve an existing controversy between, on the one hand, convincing evidence for the existence of competing order in underdoped cuprates, and, on the other hand, spectroscopic data consistent with a seemingly homogeneous d-wave superconductor in the very same compounds. Specifically, we show how short-range fluctuations of the competing order essentially restore the nodal d-wave spectrum from the qualitatively distinct folded dispersion resulting from homogeneous coexisting phases. The signatures of the fluctuating competing order can be found mainly in a splitting of the antinodal quasi-particles and, depending of the strength of the competing order, also in small induced nodal gaps as found in recent experiments on underdoped La{2-x}SrxCuO4.Comment: 5 pages, 4 figure

    Predictive monitoring research: Summary of the PREMON system

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    Traditional approaches to monitoring are proving inadequate in the face of two important issues: the dynamic adjustment of expectations about sensor values when the behavior of the device is too complex to enumerate beforehand, and the selective but effective interpretation of sensor readings when the number of sensors becomes overwhelming. This system addresses these issues by building an explicit model of a device and applying common-sense theories of physics to model causality in the device. The resulting causal simulation of the device supports planning decisions about how to efficiently yet reliably utilize a limited number of sensors to verify correct operation of the device
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