agriculture; biosystem; mechanics; engineering

Author Details

Abdullah, Kamaruddin, Indonesia

  • Vol 12, No 2 (1998): Buletin Ketenikan Pertanian - Articles

    The ratio of specifc heat capacity, at constant presszrre to that at constant volume (cdc,J, of a gas can be determined by either the adiabatic expansion method or the sound velocity method. The objective of this experiment is apply the adiabatic expansion method for determining the spec$c heat capacity ratio of gas N2 and O2 The result showed that the ratio were 1.14 and 1.19 respectively for gas N2 and 02.T he value obtained by the experiment was d~flerenta bout 15 to 19% from the result determined by theoretical method using 5 degree of Jkeedom. Theoretically cdc,, of both gas N2 and 0 2 which have 5 degree offreedom are 1.4. The dzflerence was considered to be caused by thee xperimental condition, which were not suflciently adiabatic, as required by the method. However, the simplicity of the method and clarity of its theoretical approach is advantageous to be used by students of Advance Thermodynamic class as a practical exercise.


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  • Vol 12, No 2 (1998): Buletin Ketenikan Pertanian - Articles
    The more important limitation in process design for agricultural products is the lack of information on their thermal properties. Although a lot of experimental data can be found, the variety of product and the differences ij measurement method make limitation on the value of the available data, especially for indonesia'a products. These data are needed to get information about temperature change when product was processed like hetaing or cooling. It is worth to optimize efficiency of energy. The objective of his study is to predict thermal diffusivity and conductivity of carrot. The value was determined numerically with direct and indirect methods. The result shows that thermal conductivity is 0.626 W/moC while thermal diffusivity are 2.51 x 10- m2/s (indirect method) and 2.08 x 10- 7 m2/s (direct method)
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  • Vol 12, No 1 (1998): Buletin Ketenikan Pertanian - Articles

    Baru-baru ini Gustav Grob (1996) mengingatkan lagi prediksi Club of Rome di awal tahun 1970-an bahwa bahan bakar fossil, yang sifatnya meneemarkan lingkungan, dan tak terbarukan kian berkurang keberadaannya dan dalam waktu dekat harus diganti dengan sumber energi terbarukan yang lebih bersahabat dengan lingkungan seperti sumber-sumber energi surya, biomassa, angin, hidro, dll. Ketergantungan kita atas bahan bakar fosil mungkin akan berlanjut sampai beberapa dekade lagi tetapi dalam jumlah yang jauh lebih kecil dari apa yang di konsumsikan sebelum tahun 2000 seperti terlihat pada Gambar 1 (Grob, 1996)

     


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