A calculation method of the total efficiency of wind generators

The spread of wind energy converters is progressing in recent years and its capacity is becoming larger and larger. In order to capture more energy from the wind, it is important to analyze loss characteristics of wind generators for the operating speed which is determined dependent on the wind speed. This paper presents a method to evaluate various losses in a wind generator as a function of wind speed, which is based on steady‐state analysis and thus the calculations can be performed quickly. By using the proposed method, wind turbine power, generator output, various losses, and the total energy efficiency are calculated for three types of wind speed data which are represented by a Weibull function. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(3): 52–62, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20426 Copyright © 2006 Wiley Periodicals, Inc.     

Glucocorticoids increase retinoid-X receptor alpha (RXRalpha) expression and enhance thyroid hormone action in primary cultured rat hepatocytes

A dynamic model of glucose overflow metabolism in batch and fed-batch cultivations of Escherichia coli W3110 under fully aerobic conditions is presented. Simulation based on the model describes cell growth, respiration, and acetate formation as well as acetate reconsumption during batch cultures, the transition of batch to fed-batch culture, and fed-batch cultures. E. coli excreted acetate only when specific glucose uptake exceeded a critical rate corresponding to a maximum respiration rate. In batch cultures where the glucose uptake was unlimited, the overflow acetate made up to 9. 0 +/- 1.0% carbon/carbon of the glucose consumed. The applicability of the model to dynamic situations was tested by challenging the model with glucose and acetate pulses added during the fed-batch part of the cultures. In the presence of a glucose feed, E. coli utilized acetate 3 times faster than in the absence of glucose. The cells showed no significant difference in maximum specific uptake rate of endogenous acetate produced by glucose overflow and exogenous acetate added to the culture, the value being 0.12-0.18 g g-1 h-1 during the entire fed-batch culture period. Acetate inhibited the specific growth rate according to a noncompetitive model, with the inhibition constant (ki) being 9 g of acetate/L. This was due to the reduced rate of glucose uptake rather than the reduced yield of biomass.     

Cooperative operation of a wind energy conversion system with a hydrogen electrolyzer by using an adjustable speed flywheel generator

Hydrogen is considered as the energy source of the next generation. This paper proposes a system which consists of Flywheel Generator (FWG), Wind Energy Conversion System (WECS), and Hydrogen Electrolyzer (HE), for the purpose of hydrogen generation and grid output power smoothing. The cooperative control among flywheel generator, hydrogen electrolyzer, and wind generator is performed by controlling the flywheel generator. Simulations have been done by PSCAD/EMTDC. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 168(3): 19–27, 2009; Published online in Wiley InterScience ( www.interscience.wiley. com ). DOI 10.1002/eej.20863     

Simulation of variable‐speed wind generation system using boost converter of permanent magnet synchronous generator

This paper proposes a variable‐speed wind generation system using the boost converter. The proposed system has three speed control modes for the wind velocity. The control mode of low wind velocity regulates the armature current of the generator with the boost converter to control the speed of wind turbine. The control mode of middle wind velocity regulates the DC link voltage with the vector controlled inverter to control the speed of wind turbine. The control mode of high wind velocity regulates the pitch angle of the wind turbine with the pitch angle control system to control the speed of the wind turbine. The hybrid combination of three control modes extends the variable‐speed range. The proposed system simplifies maintenance, improves reliability, and reduces the costs compared with the variable‐speed wind generation system using a PWM converter. This paper describes the control strategy and modeling for a simulation of the proposed system using Simulink of Matlab. It also describes the control strategy and modeling of a variable‐speed wind generation system using a PWM converter. The steady state and transient responses for wind velocity changes are simulated using Matlab Simulink. This paper verifies the fundamental performance of the system using a boost converter by discussing the simulation results of both systems. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(4): 37–54, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20902     

Electricity demand in the Chinese urban household-sector

This paper presents the results of estimating how much electricity is currently used and would be used in future in China’s urban household-sector. Conclusions are derived from an analysis of data obtained from a questionnaire survey recently conducted in 13 cities in China. Electricity used for various purposes in China’s urban-households is evaluated, considering climate conditions specific to the target regions and the possession of end-use appliances. How much electricity could be saved in the future by improving the efficiency of end-use lighting equipment, room air-conditioners, refrigerators, and TV sets is estimated. It is demonstrated that about 28% reduction could be achieved in the year of 2020 by means of improving the efficiency of these end-use appliances.     

An organic catalytic CVD: Principle, apparatus and applications

Organic catalytic CVD (O-Cat-CVD) is an extension of the conventional Cat-CVD technique to organic substances. O-Cat-CVD utilizes metal-organic (MO) compounds as CVD sources and provides various types of organic-inorganic hybrid materials at low substrate temperature below 200 °C. This paper introduces the research and development (R/D) to industrialize the O-Cat-CVD and related technologies in Material Design Factory (MDF) Co., Ltd. which is the first university-based venture business company of Osaka City University. Especially, this paper describes the development of a plasma-assisted catalytic CVD apparatus and the application to the growth of various types of organic-inorganic hybrid materials on plastic film substrates at low temperature.     

Planar active Yagi-like antenna

The authors introduce the Yagi concept into a simple active antenna. Antennas with director elements demonstrate an increased directivity and 30° beam-tilting compared with an active antenna     

Glycerol-3-phosphate acyltransferase in plants

Glycerol-3-phosphate acyltransferase (GPAT) catalyzes the transfer of an acyl group from an acyl donor to the sn-1 position of glycerol 3-phosphate. The plant cell contains three types of GPAT, which are located in the chloroplasts, mitochondria and cytoplasm, respectively. The enzyme in chloroplasts is soluble and uses acyl-(acyl-carrier protein) as the acyl donor, whereas the enzymes in the mitochondria and the cytoplasm are bound to membranes and use acyl-CoA as the acyl donor. cDNAs for GPAT of chloroplasts have been cloned from several plants, and the gene for the enzyme has been cloned from Arabidopsis thaliana. The amino acid sequences deduced from the nucleotide sequences of cDNAs indicate that the product of translation is a precursor of about 460 amino acid residues, which consists of a leader sequence of about 70 amino acid residues and a mature protein of about 400 residues, with a molecular mass of about 42 kDa. Genetic engineering of the unsaturation of fatty acids has been achieved by manipulation of the cDNA for the GPAT found in chloroplasts and has allowed modification of the ability of tobacco to tolerate chilling temperatures.