The ventilation effects on the ridge vent beef housing were studied by measuring outlet air speeds and other parameters in winter (Feb., 24-25 1979) and in summer (Aug., 8-9 1979).
The results obtained from this study were summarized as follows:
1) The correlation between the air discharge through open ridge and the wind speed was observed for winter observation. But it was not clear in summer observation.
2) The air discharges through open ridge under the condition of only temperature difference were approximately 230m³/min. (7.1 air changes/h) for winter observation and 200m³/min. (6.3 air changes/h) for summer obsevation. The pressure differences between inside and outside of the open ridge for winter and summer observations were estimated at 8.05×10^-2kg/m² and 3.98×10^-2kg/m², respectively.
3) The measured discharge coefficient of the open ridge was ranging from 0.57 to 0.97, the mean value of it was 0.77.
4) The calculation of vapor balance has revealed that the total ventilation rates were approximately 15 air changes/h for winter observation and 39 air changes/h for summer observation.
5) The ratios of ventilation rate through the open ridge to total ventilation rate were 0.48 for winter observation and 0.16 for summer observation.

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The soil-air heat exchange system is consisted of many pipes which are used as the heat exchangers and buried in the soil.
For burying the pipes, it is necessary to calculate for the amount of the heat exchanged between soil and air flowing through the pipes. But, there is no method for the numerical calculation.
In order that the system of soil-air heat exchange is to be recommended for controlling the air temperature in the greenhouse under the saving of the energy use, therefore, the method for the numerical calculation is urgent to be established.
Using the experimental result of the surface coefficient of heat tsansfer in this paper, the exhaust air temperature was calculated from the intake air temperature.
It was obvious that the calculated results agreed well with the experimental results. The authors concluded that the method by which the exhaust air temperature could be calculated from the intake air temperature was obtained.

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Dust accummulation in paddy drying, processing, and storage facilities was examined, and explosibilities of the dust collected in these facilities were tested by means of the Hartmann apparatus.
The dust deposited was 100-500 (g/m²) in the examined facilities and dust cloud was expected to be easily formed. The predominant substance in the dust was rice hairs (pubescences).
Chemical and phisical properties of the dust were as follows: moisture content 9-12% d. b., volatile matter content 38-50, ash 35-54, fixed carbon 8-14% moisture free basis, median particle diameter 20-60μm, calolific value 1930-2450cal/g.
In the explosibility tests, even with the undried dusts (moisture content 9-14%), all the dusts tested exploded. It can be thought that the danger of explosion is reat. The dried dusts through 200 mesh sieve indicated maximum explosion pressure of 4.3-6.1 (kg/cm²) and maximum pressure rise of 73-141 (kg/cm²·sec).

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