Vol. 11 No. 1 (1997): Buletin Ketenikan Pertanian

Nowdays, greenhouse is becoming popular in tropical country for plant cultivations, which the main reason is fbrplant protection against unwanted distwbances i.e. from heavy rainfall, wind, pest and so on. Since most of the greenhouse are covered with transparence material such as glass plate, plastic sheet, fiberglass etc., the greenhouse effect will take place accordingly causing a temperature rise that is usually higher than that of the outside. It turns out that this rising temperature becomes a major problem that will have negative effects on the plant growth. This research aims to control the temperature in the greenhouse by applying a Fuzzy Logic Controller (FLC), first by maintaining a constant temperature in the greenhouse and secondly, by trying to equalize the temperature in the greenhouse to that of the outside. The experiment was canied.out at a small scale with the greenhouse dimension of (1 00 x 120 x 100) c d Heet fnun the greenhouse was expelled using an exhaust fan. The power of the fan was: contfv&d.by the FLC subjected to the real temperaturn changes with time. The results sh~wtha t the FLC could pe~formg oad function of a temperature controller for the greenhouse.. It couM control the temperature in the greenhouse under the expected conditions end explained the energy consumption throughout the process.

This paper concerns with the development of a decision support package for chipper allocation at the transmigration land preparation area. It is intended to be used by chip entrepreneur on determining the most economical chipper allocation and man power requirement.

The package was developed by using Turbo Pascal, running well on the computers compatible with ISM PC (XT or AT) with minimum 640 Kb RAM and VGAISuper VGA monitor. Program testing showed that the program has a sufficient capability as a management tool.

Crude palm oil is one of export comodities of Indonesia. Theme, it is of crucial importance to improve the quality of crude palm oil (CPO) through the process of CPO production. This paper discusses the design and implementation of an automatic process control for crude palm oil clarification. The automatic control system proposed herein is suppoded by a computer which performs intensive computation to determine the correct volume of water required for a CPO clarification process. The computer is also used to monitor and maintain a desired temperature during the process. The implementation results indicate promising performance of the system control.

Freeze drying of food materials is a time and energy consuming process, hence a high cost process. The drying rate is limited by heat and mass transfer process within the dried portion of the product. In order to improve the freeze drying performance, it is important to know parameters which affect the drying characteristics of each spesific food material, in regard to the drying time and the energy consumption. The objective of this experiment was to study the freeze drying characteristic of miched beef especially the effect of freezing rate and surface temperature of the material to the drying time.

The study was conducted with freezing rate at 7.71 cmhours and 1.94 cmhours which are classified into fast and slow freezing rate, while the surface temperature of the material was controlled at 40 OC, 35 OC, and 30 OC. The experimental results confirmed that the faster freezing rate then the longest drying time, while the higher surface temperature give a shorter drying time of miched beef. It is important to determine the optimal freezing rate and surface temperature from the view point of energy consumption.