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Volume 25 (2008)
- Issue 4 Pages 299-
- Issue 3 Pages 239-
- Issue 2 Pages 69-
- Issue 1 Pages 1-
Volume 25, Issue 1
Displaying 1-8 of 8 articles from this issue
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Yoichi SHIMAZAKI2008 Volume 25 Issue 1 Pages 1-8
Published: 2008
Released on J-STAGE: August 30, 2011
JOURNAL FREE ACCESSThe aim of this study was to estimate the time-of-day energy demand in University of Yamanashi. Our University consisted of Kofu campus (Faculty of Education & Human Sciences and Faculty of Engineering) and Faculty of Medicine campus (Faculty of Medicine and University Hospital). The energy data of 4 facilities were classified into hot water, heating, cooling and electric power demands based on electric power consumptions, city gas and heavy oil from 1996 to 2005. For 10 years, primary energy increased 1.2 times in the whole of the university. The amount of electric power consumption was 63% in the fuel classification. The amount of electric power consumption of faculty reacted to the change in temperature greatly. In 2005, it was found that thermoelectric-ratios for 4 facilities, i.e. Education, Engineering, Medicine and Hospital were 2.3, 1.5, 2.0 and 2.7 respectively. These data are very useful for the energy saving and energy management of university.View full abstractDownload PDF (492K) -
Optimization of the Cycle Time by the Particle Swarm OptimizationTakahiko MIYAZAKI, Atsushi AKISAWA, Takao KASHIWAGI, Akira AKAHIRA2008 Volume 25 Issue 1 Pages 9-19
Published: 2008
Released on J-STAGE: August 30, 2011
JOURNAL FREE ACCESSThe study used the particle swarm optimization to maximize the specific cooling capacity (SCC) of a single-stage adsorption chiller, as well as to maximize the coefficient of performance (COP) at part load conditions of the chiller. The cycle time, which consists of adsorption/desorption time and pre-heating/ pre-cooling time, was chosen as a design parameter. The simulation results of a mathematical model showed a good agreement with experimental results on SCC and COP.
It was shown that the SCC could be improved by the optimum cycle time as much as by 30% compared with that by the fixed cycle time. It was also presented that the part load COP would be significantly increased by the cycle time optimization at part load conditions.View full abstractDownload PDF (723K) -
Yoshikazu TERAOKA, Masashi OKADA, Hirokazu TANAKA2008 Volume 25 Issue 1 Pages 21-28
Published: 2008
Released on J-STAGE: August 30, 2011
JOURNAL FREE ACCESSThe purpose of this research was to investigate the control of crystal orientation of ice by using a capillary filled with supercooling water. We used two types of capillaries: straight and triangular-wave bended, both of which were made of stainless steel and had 0.4 millimeter in outer diameter. It was found that ice crystals of various orientations grew in the straight capillaries, and at the end of the capillary, c-axes of the crystals were perpendicular to the capillary. Then, using the triangular-wave bended capillaries, about 60 percent of crystals at 0.6 K of supercooling had perpendicular c-axes to a plane containing the bended capillary. Observing crystals before and after the bended section, it was shown that whether the c-axis of the crystal after the section was controlled or not depended on the c-axis of the crystal before the section. Additionally, growth velocities of ices growing in the bended capillaries were measured. All of the crystals growing relatively quickly had perpendicular c-axes to the plane containing the bended capillary. From the results, we proposed the improvements of the system to increase probability of c-axis control.View full abstractDownload PDF (454K) -
Quantitative Evaluation of the Shape Change of Ice Crystals by Using Fractal AnalysisXin WANG, Manabu WATANABE, Toru SUZUKI2008 Volume 25 Issue 1 Pages 29-33
Published: 2008
Released on J-STAGE: August 30, 2011
JOURNAL FREE ACCESSIn this study, the shape of ice crystals in ice cream was quantitatively evaluated by introducing fractal analysis. A small droplet of commercial ice cream mix was quickly cooled to about -30°C on the cold stage of microscope. Subsequently, it was heated to -5°C or -10°C and then held for various holding time. Based on the captured images at each holding time, the cross-sectional area and the length of circumference for each ice crystal were measured to calculate fractal dimension using image analysis software. The results showed that the ice crystals were categorized into two groups, e.g. simple-shape and complicated-shape, according to their fractal dimensions. The fractal dimension of ice crystals became lower with increasing holding time and holding temperature. It was also indicated that the growing rate of complicated-shape ice crystals was relatively higher because of aggregation.View full abstractDownload PDF (403K) -
Munenaka ONODERA, Yumiko YOSHIE-STARK, Takesh SUZUKI2008 Volume 25 Issue 1 Pages 35-46
Published: 2008
Released on J-STAGE: August 30, 2011
JOURNAL FREE ACCESSThis study was performed to keep the quality and to prolong the shelf life of fresh Undaria pinnatifida, by different storage conditions. Changes of the contents of chlorophyll a (Chl a) and its derivatives, β-carotene, pH, molecular weight of alginate and molecular weight distribution were determined during the storage of U. pinnatifida. The conditions of cold storage at -3 to 7°C with air or O2, storage in seawater, and storage in slurry ice made of seawater were tested. Chl a and β-carotene contents, and the pH of U. pinnatifida were decreased following the increment of storage days. Significant decrease of Chl a content and molecular weight of U. pinnatifida was detected under cold storage especially at 7°C. The storage by icing in slurry ice and by super chilling at -3°C inhibited the degradation of Chl a and β-carotene of U. pinnatifida. The content of pheophorbide a or pH were recognized as useful factors to evaluate the quality and freshness of U. pinnatifida.View full abstractDownload PDF (677K) -
Chotika VIRIYARATTANASAK, Kiyoshi KAWAI, Manabu WATANABE, Toru SUZUKI2008 Volume 25 Issue 1 Pages 47-53
Published: 2008
Released on J-STAGE: August 30, 2011
JOURNAL FREE ACCESSWe measured glass transition temperatures in the maximally freeze-concentrated phase (Tg') of tuna and cod tissue by differential scanning calorimetry (DSC) using an annealing technique. In our experiment, the Tg' (approximately -71°C) of tuna and cod tissue did not exhibit any significant change after isothermal holding for several weeks at a temperature higher than the Tg. Another Tg' appeared above -45°C when annealing was performed at a temperature higher than -60°C for one week. We also collected Tg' data for fish flesh from many published studies and discussed them in the light of our data. The Tg' values for fish flesh in most published reports are higher than -40°C, although there have been several reports that give values of around -70°C. The high glass transition temperature (i.e., -45°C) measured in our study agrees with most of the data in the literature. Furthermore, the results suggest that the glass transition behavior at the higher temperature may be correlated to the vitrification of protein itself.View full abstractDownload PDF (386K) -
Chieko KONDOU, Shinya HIGASHIIUE, Ken KUWAHARA, Shigeru KOYAMA2008 Volume 25 Issue 1 Pages 55-62
Published: 2008
Released on J-STAGE: August 30, 2011
JOURNAL FREE ACCESSThis paper deals with an experimental investigation on the void fraction of CO2 flow boiling in a horizontal micro-fin tube. The mean void fraction in the insulated 400 mm length sampling section, which is located next to the test evaporator, has measured by the quick closing valve method. The experimental data have been obtained in mass flux range of 200 to 455 kg/(m2s) and the refrigerant pressure range of 3.5 to 5.0 MPa. It is confirmed that the relation between void fraction and quality is affected by both mass flux and pressure. The experimental results are also compared with two previous correlations for horizontal smooth tubes, which are proposed by Butterworth and Smith. The present data satisfactorily agreed with Butterworth's correlation in the range of quality from 0.03 to 0.99. However, Smith's correlation is found to predict slightly higher than present data. As a trial, the empirical correlation of void fraction, based on the experimental slip ratios, is proposed.View full abstractDownload PDF (433K) -
Norihito KIMIZUKA, Toru SUZUKI2008 Volume 25 Issue 1 Pages 63-67
Published: 2008
Released on J-STAGE: August 30, 2011
JOURNAL FREE ACCESSWe measured the ice nucleation temperature depression , ΔTf , and equilibrium melting points depression, ΔTm, of Medaka (Oryzias latipes) embryos with different cryoprotectant (ethylene glycol, 1.3-propanediol, 1.4-butanediol, glycerol aqueous solutions) treatments. Our obtained results showed the good relationship between the ΔTf ,and ΔTm all samples. In addition the value of λ , which can be obtained from the linear relationship, ΔTf =λ ΔTm, were confirmed to show correlation with the value of λ , as obtained by the W/O emulsion method.View full abstractDownload PDF (305K)
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