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Cost Solution (cost + solution)

Distribution by Scientific Domains

Engineering	50%

Selected Abstracts

Multiobjective Optimization of Concrete Frames by Simulated Annealing

COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 8 2008
Ignacio Paya
The evaluation of solutions follows the Spanish Code for structural concrete. The methodology was applied to a symmetrical building frame with two bays and four floors. This example has 77 design variables. Pareto results of the MOSA algorithm indicate that more practical, more constructable, more sustainable, and safer solutions than the lowest cost solution are available at a cost increment acceptable in practice. Results Ns -SMOSA1 and Ns -SMOSA2 of the cost versus constructability Pareto front are finally recommended because they are especially good in terms of cost, constructability, and environmental impact. Further, the methodology proposed will help structural engineers to enhance their designs of building frames. [source]

Water fluxes at a fluctuating water table and groundwater contributions to wheat water use in the lower Yellow River flood plain, China

HYDROLOGICAL PROCESSES, Issue 6 2007
Jianfeng Yang
Abstract Capillary upflow from and deep percolation to a water table may be important in crop water supply in irrigated areas of the lower Yellow River flood plain, north China. These fluxes at the water table and the variations of the capillary upflow in relation to crop evapotranspiration need to be investigated to quantify the effect of a water table on soil water balance and to improve agricultural water management. A large weighing lysimeter was used to determine daily crop evapotranspiration, daily capillary upflow from and daily percolation to a fluctuating water table during a rotation period with wheat growing in a dry season and maize in a rainy season. The water table depth varied in the range 0·7,2·3 m during the maize growth period and 1·6,2·4 m during the wheat growth period. Experimental results showed that the capillary upflow and the percolation were significant components of the soil water balance. Three distinctly different phases for the water fluxes at the water table were observed through the rotation period: water downward period, the period of no or small water fluxes, and water upward period. It implied that the temporal pattern of these water fluxes at the water table was intimately associated with the temporal distribution of rainfall through the rotation period. An empirical equation was determined to estimate the capillary upflow in relation to wheat evapotranspiration and root zone soil water content for local irrigation scheduling. Coupled with the FAO-Penman,Monteith equation, the equation offers a fast and low cost solution to assess the effect of capillary upflow from a water table on wheat water use. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Ternary single-source precursors for polycrystalline thin-film solar cells

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 11 2002
Kulbinder K. Banger
The development of thin-film solar cells on flexible, lightweight, space-qualified substrates provides an attractive cost solution for fabricating solar arrays with high specific power (W kg,1). The use of a polycrystalline chalcopyrite absorber layer for thin-film solar cells is considered as the next generation in photovoltaic devices. At NASA GRC we have focused on the development of new single-source precursors (SSPs) and their utility to deposit the chalcopyrite semiconducting layer (CIS) onto flexible substrates for solar-cell fabrication. The syntheses and thermal modulation of SSPs via molecular engineering are described. Thin-film fabrication studies demonstrate that the SSPs can be used in a spray chemical vapor deposition process for depositing CIS at reduced temperatures, and result in electrical properties that are suitable for photovoltaic devices. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Multi-stream video conferencing over a peer-to-peer network

BELL LABS TECHNICAL JOURNAL, Issue 2 2010
Adriaan J. de Lind van Wijngaarden
Video conferencing is becoming an increasingly desirable alternative to face-to-face meetings. Many companies and organizations have multiple locations, and their employees' communication options are typically limited to audio-only conference calls. These are often ineffective because of the limited level of interaction between the participants. Video conferencing is seen as a promising alternative to increase efficiency and reduce carbon emissions by mitigating the need for travel. However, current video conferencing solutions are either too expensive, require dedicated equipment and infrastructure, or are too cumbersome to implement on an individual location basis for widespread use. Low cost solutions usually provide neither the desired level of interaction nor the consistent quality needed for corporate communications. In this paper, we propose a novel hybrid video conferencing architecture that incorporates peer-to-peer communication functions for media distribution. In addition, new concepts, such as novel video cameras, cordless camera adaptors, a two-sided display, and a device that provides bidirectional remote presence are presented to enhance the experience for the remote participants. The proposed solution aims to significantly improve collaboration across sites, thus enhancing remote workplace effectiveness through low cost video conferencing, reducing the need for travel, and serving as an important enabler for eco-sustainability. © 2010 Alcatel-Lucent. [source]