Energy Conservation Rate Research Articles

Joint Power and Rate Adaptation in Ad Hoc Networks Based on Coupled Interference

To optimize performance of ad hoc networks, the contradicting objectives: energy conservation and high data rate realization need to be jointly considered. In such a case, network interference need to be controlled in a manner that users transmit at minimum power enough to sustain the transmission. This paper proposes a joint power and rate adaptation in ad hoc network based on coupled interference minimization (PRIM) where the formulated network utility maximization (NUM) is solved using reverse engineering based on Karush-Kuhn-Tucker (KKT) conditions. In that way, users determine their transmit power and data rate based on their local observations (coupled interference). Pricing mechanism is employed in PRIM to restrict users from self-interest behaviours. It is demonstrated theoretically that PRIM satisfies the conditions of the super-modular games such that the local optimality is always the global optimality. Simulation results have shown that adapting transmits power and data rates based on the coupled interference (i.e. link dynamics) can improve the performance of ad hoc networks.

Species-independent maintenance energy and natural population sizes

A general strategy to estimate the size of an active microbial community based on catabolic rates was developed. Tijhuis et al. (Biotechnol. Bioeng. 42, 1993, 509–519) calculated from chemostat experiments maintenance energy consumption rates by multiplication of the maintenance substrate consumption rate with the standard free energy of the catabolic reaction. They showed that the maintenance energy can generally be described as species-independent by an Arrhenius equation. In the present communication, it is shown that the theory is applicable for different microbial culture systems. For a given environmental situation, the maximal microbial population size is obtained when the free energy conserved is consumed solely for maintenance of the cell. The free energy conservation rate per volume together with the species-independent description of maintenance energy enables calculations of the maximal population size corresponding to a catabolic rate and of maintenance substrate consumption rates for microbial cultures.

農作物生産用温室へのコージェネレーションシステム適用性評価

In greenhouses for crop production in Japan, large-scale/intensive management has advanced in recent years due to price competitiveness for import crops and the structural shortage of workers, and energy-conserving measures have become an important issue.The purpose of this study was to provide practical strategies for application of Combined Heat and Power, CHP in short, to effective energy conservation in greenhouses. The authors have performed energy demands measurement at existing large tomato greenhouses in Japan for 4 years, and investigated the effectiveness of CHP operated for the greenhouses. Model analysis revealed the following results.(1) The ratio of Heat to electricity in the greenhouses is zero in all time zones except the carbon dioxide Fertilization time in summer while 60 during maximum Heating time in winter, showing a particular characteristic of energy consumption in greenhouses.(2) Relatively larger-sized CHPs are useful for larger-scale greenhouses to attain the energy conservation rate of 3 to 4%.(3) From the economic aspect of tomato production, the scale of greenhouse should be 5×104m2 or more, and gas engine CHP is superior to micro gas turbine. Combined use of a boiler is necessary to satisfy heat demands and carbon dioxide fertilization.

Non‐linear behavior of mass concrete in three‐dimensional problems using a smeared crack approach

AbstractA smeared crack approach has been proposed to model the static and dynamic behavior of mass concrete in three‐dimensional space. The proposed model simulates the tensile fracture on the mass concrete and contains pre‐softening behavior, softening initiation, fracture energy conservation and strain rate effects under dynamic loads. The validity of the proposed model has been checked using the available experimental results under static and dynamic loads. The direct and indirect displacement control algorithms have been employed under incremental increasing static loads. It was found that the proposed model gives excellent results and crack profiles when compared with the available data under static loads. The Koyna Dam in India has been used to verify the dynamic behavior of the proposed model. It was found that the resulting crack profiles were in good agreement with the available experimental results. Finally, the Morrow Point Dam was analyzed, including the dam–reservoir interaction effects, to consider its non‐linear seismic behavior. It was found that the resulting crack profiles were in good agreement with the contour of maximum principal stresses and no numerical instability occurred during the analysis. Copyright © 2004 John Wiley & Sons, Ltd.

Identifications: inevitability of RVRs being approximately the same under different meteorological conditions when taking the same energy-saving measures in the same building

By making comparative research on hourly, daily and monthly energy consumption differences and also on energy conservation rates of heating and cooling when taking the same energy-saving measure in the same building in typical-year meteorological conditions (WDB1) and artificial meteorological conditions (WDB2), we can find from this paper that although the hourly heating and cooling load has great differences when making the same energy efficient measure in the same building under WDB1 and WDB2, the distribution laws of hourly energy efficiency rates (RVRs) of heating and cooling are very similar. It is just the similarity that determines the inevitability of approximation of annual energy conservation rates of heating and cooling. The importance of this paper is that it reveals the common rule of building efficiency. When making the same energy-saving measure on the same type of building in different regions the annual energy consumption and its reduction of the building have a great difference between the regions and the energy conservation rates (RVRs) of the same measures are approximate. After taking some energy-saving measure on the same building in the same place, within the lifetime of the building, however different the local weather conditions over the years are, the energy consumption of different years and the energy reductions of the measure must be different. However, it can be foreseen that the energy conservation rate of any year is approximate after making energy-saving measures on the building. The reason for the above is that although climate changes between years, there is nothing more impractical in artificially modifying meteorological conditions (WDB2), which provides a powerful theoretical basis for every country to lay down design standard for energy efficiency.

Species-independent maintenance energy and natural population sizes

A general strategy to estimate the size of an active microbial community based on catabolic rates was developed. Tijhuis et al. (Biotechnol. Bioeng. 42, 1993, 509–519) calculated from chemostat experiments maintenance energy consumption rates by multiplication of the maintenance substrate consumption rate with the standard free energy of the catabolic reaction. They showed that the maintenance energy can generally be described as species-independent by an Arrhenius equation. In the present communication, it is shown that the theory is applicable for different microbial culture systems. For a given environmental situation, the maximal microbial population size is obtained when the free energy conserved is consumed solely for maintenance of the cell. The free energy conservation rate per volume together with the species-independent description of maintenance energy enables calculations of the maximal population size corresponding to a catabolic rate and of maintenance substrate consumption rates for microbial cultures.

A fundamental study on fluidized bed combustion with a radiation energy convertor.

This study was carried out to clarify the effects of a radiation energy convertor (porous medium) employed in a fluidized bed combustor. The effects of a porous medium were investigated for various conditions which include the bed temperature, stable combustion state, combustion load, excess air ratio and energy conservation rate. In order to clarify these effects in detail city gas was used as the combustion fuel. The experimental results reveal that a higher bed temperature and wide stable combustion range can be obtained by installing a porous medium. Especially, the required combustion loads can be reduced to 50-70% of that needed when a porous medium is not used under the conditions that the bed temperature and excess air ratio are maintained uniformly. This combustion technology may be applied for developing a combustion system of extremely low calorific fuels such as high water content materials.