Iron Loss Analysis of Permanent Magnet Motors Fed by PWM Inverter

Carrier harmonic losses that consist of iron loss, eddy current loss, and ac copper loss are produced in a permanent magnet machine driven by a PWM inverter. It is already known that a higher motor inductance can lead to lower carrier harmonic losses. This paper investigates the carrier harmonic loss composition of two motors with identical dimensions but different inductances. The results of finite element analysis (FEA) showed that the eddy current loss in the iron core accounts for most of the carrier harmonic loss. It is also shown that the carrier harmonic loss of the iron core is quantifiable using theoretical calculations.     

NONENZYMATIC BROWNING IN CLARIFIED APPLE JUICE AT HIGH TEMPERATURES: A RESPONSE SURFACE ANALYSIS

The effect of temperature and soluble solids on nonenzymatic browning in clarified and concentrated apple juice was analyzed by response surface methodology. Color development at 20, 40 and 60 Brix and temperatures ranging from 70–90C were compared over a time range of 30–180 min. the browning reaction was found to be dependent on soluble solid content as well as on the reaction conditions such as temperature and time. the model combines the effect of temperature, soluble solids content and time on color change due to nonenzymatic browning.     

Induction of adaptive response <i>in utero </i>by ionizing radiation: A radiation quality dependent phenomenon

Investigation on possible induction of adaptive response (AR) by high-liner energy transfer (LET) particle radiation for protection against low-LET photon radiation-induced detrimental effects has not yet been performed in utero. This study verified if an AR could be induced by high-LET particle radiation from accelerated heavy ions against low-LET X-ray radiation-induced detrimental effects on fetal mice. Total body irradiation of pregnant C57BL/6J mice were performed by delivering a priming dose ranging from 10 mGy to 320 mGy of particle radiation on gestation day 11 followed one day later by a challenge dose at 3500 mGy from X-ray radiation. The monoenergetic beams of carbon, silicon and iron with the LET values of about 15, 55, and 200 KeV/μm, respectively, were examined. Significant suppression by the priming radiation of the detrimental effects (fetal death, malformation, or low body weight) was used as the endpoints for judgment of a successful AR induction on gestation day 18. Existence of AR was not observed. On the other hand, the priming dose of high-LET particle radiation, in some cases, even increased the detrimental effects induced by the challenge dose from low-LET X-ray radiation. Although existence of AR induced by high-LET radiation in cultured mammalian cells in vitro and in certain tissues of laboratory mice in vivo was demonstrated, the present study did not suggest that low dose of high-LET particle radiation could induce an AR in fetal mice in utero under the setup of our experimental system.     

EFFECT OF RELATIVE SLIP AMPLITUDE ON FRETTING FATIGUE OF HIGH STRENGTH STEEL

Abstract— The effect of relative slip amplitude on fretting fatigue in high strength steel was studied at various contact pressures using fretting pads of various lengths. Under a given contact pressure, the fretting fatigue life showed a minimum at a certain relative slip amplitude. Under a fixed pad length, the life also showed a minimum at a certain contact pressure. A map of fretting fatigue life versus contact pressure and relative slip amplitude was obtained using the data of this study. The map indicated that both the phenomena which showed a minimum life in relation to slip dependence and contact pressure dependence were the same, as were the underlying mechanisms. The minimum life was interpreted in terms of local stress concentration at the fretted area.     

PERCEPTION OF GRITTINESS IN AN OIL-IN-WATER EMULSION

Microcrystalline cellulose was dispersed as a gritty substance in an emulsion, and sensory evaluation was conducted to examine the effect of the presence of oil on grittiness felt in the mouth. Samples were prepared with three types of microcrystalline cellulose of average particle size 14, 38, and 76 μm and with a concentration in water of 0.03–2.7%, with three types of emulsion with an oil-volume fraction of 0.2–0.7, and with three rates of homogenization of 500–15,000 rpm. The flow behavior and loss modulus of each sample were measured and sensory evaluation was made of the perceived grittiness. A multiple regression analysis of the data shows that the proportion of people who could perceive grittiness was influenced by the following factors and in that order: concentration of microcrystalline cellulose, oil droplet size, loss modulus, and particle size of microcrystalline cellulose. The proportion of people who perceived grittiness also increased with increasing oil droplet size. This was conceivably caused by the uneven distribution of microcrystalline cellulose particles promoted by large oil droplets. An equation was developed relating the proportion of people perceiving grittiness to the physical properties of the sample. The result indicates that factors effecting grittiness perception are identical for emulsions, aqueous suspensions, viscous suspensions and gels, studied previously.     

落压比对射流控制矢量喷管性能影响研究

文中利用数值模拟方法研究了落压比对射流控制矢量喷管流动和性能的影响,分析了喷管矢量角随落压比变化的机理。研究结果表明,随着落压比增大,矢量角减小;注气口下游分离区内的压力降低,上下壁面的压差减小,矢量角减小;喷管工作状态从过膨胀状态向欠膨胀状态转变,压差产生的推力越来越大,喷管的矢量角和气流偏转角相差越来越大,矢量角越来越小。     

SEISMIC RETROFITTING FOR BRIDGES IN OSAKA CITY

In the wake of the Hanshin-Awaji Earthquake, the Osaka Municipal Government has planned and executed seismic retrofitting for bridges in Osaka.

This report first discusses the present condition of bridges in Osaka, and changes in bridge design standards. Next, it explains the basic concept underlying bridge seismic retrofitting, derived from the experience of the Hanshin-Awaji Earthquake.

In planning retrofitting, evaluation criteria on the importance and seismic capacity of all bridges in Osaka were established. Based on these criteria, the bridges were classified into five ranks each. Evaluation results were indicated in the form of a matrix.

Using the matrix, retrofitting methods and priority were determined. According to plan, about half of the bridges in Osaka will be retrofitted.     

Conductive indium-doped zinc oxide films prepared by atmospheric-pressure chemical vapour deposition

Abstracts are not published in this journal