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Volume 28 (1997 - 199･･･
- Issue 4 Pages 193-
- Issue 3 Pages 125-
- Issue 2 Pages 53-
- Issue 1 Pages 3-
Volume 28, Issue 2
Displaying 1-5 of 5 articles from this issue
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Efficiency of Ozone and Ultraviolet Light TreatmentsKeo INTABON, Takaaki MAEKAWA1997 Volume 28 Issue 2 Pages 53-60
Published: September 25, 1997
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSThe efficiency of ozone and ultraviolet irradiation (UV-C) to inactivate the bloom particles in liquid phases sampled from culture medium and natural water body was tested. Only UV-C performed the higher inactivation efficiency for both water culture and natural water samples. Using culture water samples, UV-C could eliminate completely algal activity with chlorophyll a (chl. a) content up to 327μg/L. Even a complete elimination was observed for a sample with chi. a content of 74.7μg/L, the UV-C efficiency on natural water samples was uncertain. This uncertainty was seemed to be derived from both natures of SS particles and ecological structure of the algal bloom in the natural samples. Using natural water samples, it is simulated that mechanical destruction of SS clusters and algal flock should be needed in order to increase UV-C efficiency.View full abstractDownload PDF (856K) -
Analysis of the cooling load in summer nighttimeYuichi KOBAYASHI, Tohru SHIGA, Nobuaki FUJISHIGE, Takahiro SAITO, Yosi ...1997 Volume 28 Issue 2 Pages 61-68
Published: September 25, 1997
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSGreenhouse water spray cooling system is developed for night cooling treatment for raising seedling in summer time. This system adopts a closed-type water curtain cooling system, adding fog spraying of cold subterranean water as a cold source. The relationship is analyzed among the environmental factors, such as inside, outside and ground temperatures of greenhouse and volume and temperature of sprayed water. In the initial period of cooling when the greenhouse is shut and water is sprayed, the heat load for cooling inside the greenhouse, especially vapor condensed heat load is very large. At the steady period late at night, the main heat load for cooling is the heat transmission from the roof of the greenhouse. This water spraying system is able to quickly remove the large amount of initial heat load to lower the inside temperature, and proves to be useful for greenhouse cooling at night in summer. To control the inside temperature by spraying subterranean water, multiple regression analysis calculates the inside temperature from the outside temperature and the temperature and volume of sprayed water. It shows that controlling the volume of sprayed water makes the inside temperature optimum for night cooling of strawberry seedling. Moreover, controlling the volume of water saves subterranean water, leading to energy saving, and this system proves to have high potential to spread for practical use.View full abstractDownload PDF (940K) -
Takaaki MAEKAWA, Yan Sheng ZHANG, Zhen Ya ZHANG1997 Volume 28 Issue 2 Pages 69-75
Published: September 25, 1997
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSBacth methane fermentation from acetic acid was carried out with acclimated-methanogens using stopped culture tube at pH 7 and 37°C. The effects of trace metals solution added to the medium for methane formation from acetic acid were investigated in two cases, lower initial cell density of methanogens (0.06g/L) and higher initial cell density of methanogens (0.6g/L). Optimum trace metals solution for methane formation rate were obtained on both cases. At early stage of the tube cultivation, the maximum methane formation rate was obtained at 0.1mL/L of trace metals solution for lower initial cell density. As cultivation time was elapsed, the trace metals solution concentration that maximum methane formation rate obtained was changed to higher than that of 0.1mL/L. In contrast with the case of 0.1mL/L of trace metals solution, methane formation rate was doubled at 10mL/L of trace metals solution after 16 days of cultivation. However, in the case of a higher initial cell density, the maximum methane formation rate observed at higher concentration of trace metals solution concentration of 15mL/L, which is 150 times greater than that of previous report. Inhibition of methane formation at high concentration of trace metals solution (more than 15mL/L) was observed at early stage. As cultivation time was elapsed, the inhibition with the high concentration of trace metals decreased. During 2 to 7 days of cultivation, the rate of methane formation was 3.7 times higher than that of 0.1mL/L of trace metals solution concentration.
It was found that inhibition due to the high concentration of trace metals solution depended on inoculation size of methanogens, and high rate of methane formation can be obtained by optimizing the concentration of trace metals solution added to the medium.View full abstractDownload PDF (715K) -
under quasi-steady state operationShi-Qing WANG, Shun-ichiro TANAKA, Fumihiko TANAKA, Kazuo MORITA1997 Volume 28 Issue 2 Pages 77-85
Published: September 25, 1997
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSNumerical model equation was developed to predict or to control the temperature and humidity of air in wrapper type cold store. The model was based on heat and mass balance of moist air, and was solved using the Runge-Kutta-Gill method. Exhaust air conditions from an unit cooler and outer air conditions were used as model inputs. For validation of the model, data were collected. The model predicted temperature and humidity of moist air compared reasonably well with the observed values. Air conditions in wrapper were maintained constant when the store system was under quasi steady state operation.View full abstractDownload PDF (998K) -
Hisashi KOWATA, Yoshikazu SATO1997 Volume 28 Issue 2 Pages 87-94
Published: September 25, 1997
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSAn ice pond system with a 200m3 ice pond was operated to refrigerate a storage warehouse, and heat transfer through the surfaces of the ice pond and the heat gain by storage cooling were measured and calculated by heat transfer analysis. The calculated values of heat transfer agreed with the measured ones. During the ice storage, the heat gain through the top surface of ice mass was about three fourths that of the total, and too large in comparison with the heat from the side slopes and bottom. It showed that the improvement of insulation on this surface is the most important and effective to control ice melting. The heat gain through the aboveground part of side slopes was relatively greater than both of the underground part and the bottom of the ice pond. The cooling with the ice pond was feasible until the end of August. Though a small percentage of the total energy of produced ice was used effectively for storage cooling in the experimental facilities, the analysis proved that the energy extraction efficiency in-creases in proportion with cooling capacity per top surface area of ice.View full abstractDownload PDF (2594K)
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