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Volume 12 (1982)
- Issue 2 Pages 5-
- Issue 1 Pages 2-
Volume 12, Issue 1
Displaying 1-5 of 5 articles from this issue
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Naoki SAKAI, Kosei TSUNODA1982 Volume 12 Issue 1 Pages 2-7
Published: February 09, 1982
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSThe authors examined the effects of measurements and moisture content on bulk density of grains.
From the test on measurements the ratios of maximum values to mimimum values were 1.05 for soy bean, 1.13 for barley and 1.10 for wheat.
Excepting rough rice, bulk density of grains increased as moisture content decreased.
The compressibility curve of grains were classified into 3 groups.
In rough and hulled rice, the measured values of partticle density agreed with the published values.
From the measurement of N (the number of particles in unit volume) and G (the mass of a particle), the difference of rough rice from other grains was showed.View full abstractDownload PDF (720K) -
Shyusaku KATAYAMA1982 Volume 12 Issue 1 Pages 8-13
Published: February 09, 1982
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSThis paper describes the energy conservation techniques for a heating greenhouse. The overall heat transfer coefficient (U-value) was measured by using a hot box model and two actual small greenhouses which were a wooden frame house and a steel frame one.
By the hot box model, two cases of covering conditions were measured, one of them consisted of a PVC film for covering and steel frames, another was a PVC film only. The U-value of the Covering with frames was 10% greater than that of the covering alone. Likewise, in comparison of effect of frame materials in the greenhouses, the wooden frame one had 11% less U-value than the steel frame one. Those differences are considered to result from a kind of frame materials and their size of contact area with a covering material.
In addition to above facts, the changes in U-value of the greenhouses were mearsured as a functioned of wind verocity
Furthermore, a simple method for estimating U-value is described for any greenhouses consisting of various materials for covering and framing.View full abstractDownload PDF (813K) -
Characteristics of Moisture Content of Received and Standing PaddyKiyokazu GOTO, Ritsuya YAMASHITA1982 Volume 12 Issue 1 Pages 14-20
Published: February 09, 1982
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSIn order to optimize the design and usage of Paddy Drying and Storage Facility, it is effective to get the characteristics of moisture content of received paddy in the facility. In this paper, the multiple regression equation of moisture content was proposed. Moreover, the moisture content of standing paddy which influences the change of moisture content of received paddy was studied.
1. The distribution of moisture content of received paddy is approximated by normal distribution, and the linear relationship between the mean and standard deviation was obtained.
2. The predictor variables of weather condition such as receiving day (D), precipitation of the day before (P'), duration of sunshine (S), and relative humidity (H) were selected for the analysis. The multiple regression equation shown in Eq. (5) was derived from data measured for 4 years, and the coefficient of multiple correlation is about 0.7.
3. The moisture content of standing paddy starts to decrease at daybreak, and the drying rate is about 0.7% w.b./h. The moisture content of standing paddy is lowest at 4-5p.m., then the absorption occurs untill daybreak of next day.
4. The standing paddy absorbs or dries due to the difference of the equilibrium moisture conetent, and the absorbing constant (or drying) is about 0.25h-1.
5. The effect of precipitation on the moisture content of standing paddy remains on the next day, and this fact corresponds to the effect of the precipitation of the day before on the multiple regression equation of the moisture content of received paddy in the facility.View full abstractDownload PDF (823K) -
Kiyohiko TOYODA, Takaaki MAEKAWA, Shingo YAMAZAWA1982 Volume 12 Issue 1 Pages 21-28
Published: February 09, 1982
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSThis investigation was carried out to estimate the thermal properties, convective heat transfer coefficient, intraparticle heat conductivity and so on, in the heat transfer experiment of single kernel as the minimum unit of the packed bed.
The effect of moisture evaporation in the heat transfer experiment could be neglected because of adoption of dried material (5% w.b.), rough rice and barley.
The propriety of the method in the experiment and analysis was estimated in comparison between result of glass bead and the literature on glass bead. The results obtained from this study were summarized as follows:
1) The surface area of rough rice calculated from the equivalent diameter by Smiths' geometry index is 0.75 times as large as the mesured surface area (av=2636.1m2/m3). Therefore, the convective heat transfer coefficient of rough rice, hp, calculated from equivalent diameter, is overestimated about 35 percent.
2) The intraparticle heat conductivity was estimated from the sinking method of marcury tank.
rough rice: 0.267kcal/mhr°C, barley: 0.358kcal/mhr°C, glass bead: 0.547kcal/mhr°C
3) The convective heat transfer coefficient was obtained by measuring the center temperature of a particle.
rough rice: Nu=0.334 Re0.407 (60≤Re≤180)
barley: Nu=1.350 Re0.275 (20≤Re≤230)
glass bead: Nu=2+1.070Pr1/3 Re0.379 (60≤Re≤340)
4) The equation of the convective heat transfer coefficient, hp, was derived from the exact form equation with reference of the center temperature, which describes temperature distribution within a homogeneous particle. The Biot Number calculated from the value of hp, was larger than 0.1 over the experiment range (Va: 0.1-1.0m/s), and it was obious that intraparticle resistance of heat transfer shouldn't be neglected.View full abstractDownload PDF (825K) -
Toshiyuki TAKAHASHI, Hiromichi KATO, Hiroshi FUKUCHI1982 Volume 12 Issue 1 Pages 29-32
Published: February 09, 1982
Released on J-STAGE: September 05, 2011
JOURNAL FREE ACCESSDownload PDF (527K)
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