All issues
Volume 48, Issue 3
Displaying 1-10 of 10 articles from this issue
- |<
- <
- 1
- >
- >|
-
Hirakazu SEKI, Tomoaki KOMORI1992 Volume 48 Issue 3 Pages 225-235
Published: December 10, 1992
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSMass, energy and exergy balance equations for a batch reactor of composting were derived with several assumptions, using various information on composting which had been obtained from previous investigations. In the batch reactor, temperature, moisture content and chemical composition were regarded to be homogeneous. According to the numerically calculated results under the practical operating conditions, a structure of energy conversion in composting process was quantitatively discussed. A ratio of the amount of heat accumulated within the reactor to the total amount of heat generated in the reactor, Hacc/Hgen, decreased with time, while a ratio of the amount of heat lossed from the reactor to the total amount of heat generated in the reactor, Hloss/Hgen, increased with time. On the other hand, about 90% of the total amount of exergy generated in the reactor was occupied by the dissipated exergy because of irreversibility of the process. It was found out that there would be a remarkable qualitative degradation of energy in the energy conversion process of composting from chemical to thermal energy, and that an exergy efficiency of heat recovery would be at most 10% even by an ideal heat recovery system.View full abstractDownload PDF (1350K) -
Hirakazu SEKI, Tomoaki KOMORI1992 Volume 48 Issue 3 Pages 237-246
Published: December 10, 1992
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSHaving had imagined the heat recovery from exhaust air out of a compost bed, experiments for rising the temperature of water (medium fluid) by a packed column heating tower of counter flow-type were conducted. There was a considerably larger temperature rise of water (30°C of the maximun), and a higher value of the heat recovery efficiency (72% in average), as compared with those for the buried-tube-type heat extractor. Therefore, the proposed heat recovery system seemed likely to be valid.
An overall volumetric coefficient of enthalpy transfer of the tower Ka depended only on the mass velocity of dry air G, and it was arranged by the experimental equation Ka=27G0.76 within the error of±20%.
Assuming the linearity between the enthalpy and temperature of saturated air, approximate solutions of the temperature of water and the enthalpy of moist air in the tower were derived.
It was illustrated that the volume of compost bed and the mass velocity of water in the tower which would be required to get the desired water temperature at the outlet of the tower could be graphically determined by the approximate solutions.View full abstractDownload PDF (1122K) -
Hiroshi HAMAMOTO1992 Volume 48 Issue 3 Pages 247-255
Published: December 10, 1992
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSI investigated the effects of floating row cover with spunbonded polypropylene on environmental factors (air, soil and plant temperature, vapor pressure deficit, matric potential of soil water, wind velocity, CO2 concentration and boundary layer resistance) and growth of spinach (Spinacia oleracea L.).
The row cover reduced the inside air flow. Air temperature and plant temperature were higher under the row cover especially during the calm and clear daytime. During nighttime, the row cover maintained only temperatures of growing points and lower leaves higher than outside.
Under the row cover, soil temperature and matric potential of soil water were higher than outside. No significant difference was found in vapor pressure deficit or CO2 concentration. Boundary layer resistance was increased by the row cover.
Net photosynthesis per unit leaf area was often lower in spinaches under the row cover than the plants outside despite the greater stomatal aperture of covered spinach leaf. Nevertheless, covered plants grew rapidly than noncovered ones. This may be resulted from rapid appearance and extension of leaves which are influenced by the increased temperatures and soil water content.
Higher temperature, in the daytime in particular, and higher soil water content under the floating row cover might be primary factors in the enhanced plant growth.View full abstractDownload PDF (1115K) -
Hiroshi HAMAMOTO1992 Volume 48 Issue 3 Pages 257-264
Published: December 10, 1992
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe purposes of this investigation are (A) search of environmental factors affecting the plant growth under the row cover and (B) separation of daytime and nighttime row cover effects. For the investigation, four experimental sections were arranged as follows; a: all day covered, b: daytime (8:00-16:30; from Sep. 11 in 1989 to Mar. 25 in 1990, 8:00-17:30; from Mar. 26 to Sep. 18 in 1990) covered, c: nighttime (16:30-8:00; from Sep. 11 in 1989 to Mar. 25 in 1990, 17:30-8:00; from Mar. 26 to Sep. 18 in 1990) covered, d: noncovered. Spunbonded polypropylene fabric was used for the cover. In each section Japanese komatsuna (Brassica campestris L.) and spinach (Spinacia oleracea L.) were cultured and air temperature, vapor pressure deficit, soil temperature at a depth of 10cm and matric potential of soil water at a depth of 15cm were observed.
Plants in sections a and b grew at a similar rate. In these sections, plant growth was promoted in cold periods and inhibited in hot periods. Effect of the nighttime covering on plant growth was not clear. Therefore the row cover effect on the plant growth depended on the environmental change during daytime.
Daytime air temperature was the environmental factor which was changed by the all day or daytime covering and not changed by the nighttime covering. Row cover effects on the plant growth are closely related to the change of the daytime air temperature by the covering.
The all day covering promoted the plant growth during periods when daytime air temperature inside cover was closer than the daytime air temperature outside to the optimum temperature for plant growth. Conversely, plant growth was inhibited during periods when daytime air temperature outside was closer than the daytime air temperature inside to the optimum temperature for plant growth. In periods when inside and outside daytime air temperature were both optimum, the row cover effect on the plant growth was not significant.
Whether or not the row cover promotes plant growth depends on whether the cover makes a daytime air temperature near to optimum for the plant or not.View full abstractDownload PDF (1016K) -
Junsei KONDO1992 Volume 48 Issue 3 Pages 265-275
Published: December 10, 1992
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe objective of this study is to develop a method of estimating the surface heat flux by use of routine meteorological data. Analytical solutions are shown for cyclic variations of the surface temperature (Ts), sensible heat flux (H), latent heat flux (lE), and ground conductive heat flux (G), as functions of effective incoming radiation (R↓) and air temperature (T) with the surface parameters—exchange coefficient (CHU), surface moisture availability (β), and ground thermometric parameter (cgρgλg).
By application of the present formulation to nocturnal cooling in calm night, the value of cgρgλg is obtained. With use of the observed daily variation of the surface temperature, the value β is evaluated so that daily march of the sensible and latent heat flux can be obtained.View full abstractDownload PDF (1424K) -
Nobuhiro MATSUOKA, Noriaki YAMAZAKI, Keiichi NAKAYAMA, Hisashi KON, Hi ...1992 Volume 48 Issue 3 Pages 277-283
Published: December 10, 1992
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSNighttime temperature is mainly determined by two factors. One is its altitude and the other is its topographical feature, surface condition or effects of sea. Therefore, to evaluate nocturnal cooling, we must remove altitudinal effect from nighttime temperature. In this study, we showed the way to evaluate cooling using temperature data from NOAA/AVHRR and numerical terrestrial data of Hokkaido-Island in Japan.
Lapse rate of surface temperature for the meshes which had the highest temperature at the altitude, was equal to that of air temperature of atmosphere. Therefore we can calculate surface temperature without the altitudinal effect, by subtracting the estimated highest temperature of the altitude, from the real surface temperature. Thus, we defined the cooling of the mesh as the remainder temperature of the subtraction.
Using the cooling, it was clarified that basins and valleys are cooled more excessively than plains.View full abstractDownload PDF (4900K) -
Masayuki HIRAFUJI1992 Volume 48 Issue 3 Pages 285-293
Published: December 10, 1992
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSA plant growth model is developed with an organ growth network (OGN). An OGN consists of algebric equations derived from Lotka-Volterra equations (LVEs), which represent the mechanism of competitive interference between organs as a first ordrer approximation, where it is supposed that the magnitude of interference between organs is smaller than the intrinsic growth rate of all organs. For calculations involved in the search for equilibrium points equal to the solutions of the original LVEs, the state of an OGN changes according to the same daynamics as neural networks. The calculation time is much shorter than that of the numerical integration of the original LVEs. An algorirhm of identification for OGNs is proposed based on the back-errorpropagtion algorithm extended for OGNs.
These modeling methods and the algorithm have been confirmed with a simple example problem and identification of the specific OGN model. Using observed data of soybeans grown in Japan, an OGN model is identified. The results of the identification of relationships between organs are similar to those obtained from translocation of souce organs to sink organs.
The above modeling method includes new concepts for understanding the dynamics of biological systems as information processing systems.View full abstractDownload PDF (1099K) -
Working Group of Meteorological Improvement Studie1992 Volume 48 Issue 3 Pages 295-297
Published: December 10, 1992
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (401K) -
Biological, Engineering and Socioeconomic AspectsSectreatriat of International Symposium on Transpl1992 Volume 48 Issue 3 Pages 299-302
Published: December 10, 1992
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (5868K) -
Atsushi Kano1992 Volume 48 Issue 3 Pages 303-304
Published: December 10, 1992
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (210K)
- |<
- <
- 1
- >
- >|