Judul: The effects of vibration and heat energy on cabinet type ghe solar dryer
Abstrak: Increasing heat and vapor transfer between air and product to be dried is an important issue in drying of agricultural products. Generally, manual mixing is used in order to increase the contact area between air and product to be dried. However in most types of dryer including GHE solar dryer this method will result in significant heat loss and inconvenient operation. In order to overcome the problem, a GHE solar dryer prototype equipped with vibrating method on drying cabinet was designed in this study. The objective of this study is to perform analysis and simulation about vibration and heat transfer process in cashew nut drying by using cabinet type GHE solar dryer. The designed prototype had dimensions namely length, width, and height respectively of 1 m, and drying capacity of 30 kg of cashew nuts. The heat source was solar energy and coal fuels. The vibration components were placed just below the drying rack serves to smooth the flow of hot air into the cashews which was put on the drying trays. The vibration component consist of motor, shaft and unbalance mass mounted to the shaft. Based on the experimental result, the effective motion of the samples being dried occured at rotational speed near its natural frequency for total mass of 20 kg as well as of 40 kg. The final moisture content of vibrated samples was lower (i.e. 3.5%) than the samples without vibration (i.e. 4.2%). The results of testing of cabinet type GHE solar dryer is obtained that the utilization of solar energy just as energy sources drying will result dryer air temperature below 60 ° C. Therefore, additional heat energy required from coal-burning fuels that can raise the temperature of air in the drying chamber. Increased air temperature in the drying chamber requires heat energy and heat exchanger out of qAPK = 23.3 kJ / s, and the results obtained through experiments showed that the average air temperature in the drying chamber can be reached, Trg = 59.6 °C. This heat exchanger has a length of 40 cm, width 60 cm, 30 cm high and made of aluminum material with a thickness of each plate of 1 mm. Furnace fuel placed under the heat exchanger and is equipped with manual equipment that can raise and lower positions of fuel so that the temperature varies in the drying chamber during the experiment can be minimized.
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Judul: Simulasi Proses Pengeringan Jagung Pipilan dengan Mesin Pengering Surya Tipe Efek Rumah Kaca (ERK)-Hybrid dengan Wadah Silinder
Abstrak: Generally uniformity of moisture content was difficult to be reached due to un-mixed product during drying process. A study on performance of hybrid-green house effect (GHE) solar dryer with rotary drum chamber for shelled corn drying has been conducted. The objectives of this research were: to evaluate performance of hybrid-GHE solar dryer with cylinder type, to develop model to predict temperature, relative of humidity, and decreasing of shelled corn moisture content and to validate the model which developed by the experimental data. The model was constructed based on heat and mass balance. The models were solved by Euler’s finite difference method. Three experiments have been conducted and the results showed that the range of room temperature and relative hummidity were 34.0-41.0 °C and 60.2-76%, respectively. Based on this condition, 1114.1-1304.3 kg mass of shelled corn with the initial moisture content 22.28-24.87% wb. could be dried until to 15.92-17.58% wb. in 8-11 hours. By rotating the cylinder 15 minutes per hour, difference of inside and outside temperature of shelled corn layer was 0-9.8°C and moisture content was 0-2.3% wb. The drying capacity was 118.57-161.76 kg/h. Spesific energy consumption and main cost were 6.03-10.13 MJ/kg and 75.89-124.37 Rupiah/kg, respectively. Total efficiency with solar iradiation and without solar iradiation were 19.88-39.15% and 22.51-46.06%, respectively. The models that had developed has already explain the experiment data. Coefficient of determinant (COD) of model with experiment data for room temperature, relative of humidity, grain temperature, water tank temperature, and moisture content were 0.74, 0.09, 0.35, 0.91 and 0.98, respectively. The absolute percentage deviation (APD) were 1.29%, 5.89%, 1.79%, 3.5% and 0.86%. Simulation for rotating cylinder showed that by continuous rotating had the highest influence for uniformity of temperature and moisture content. The result showed that this treatment had smallest difference of inside and outside temperature and moisture content were 0.05-1.78°C and 0.14-0.56% wb. respectively. Simulation for input changing showed that by using higher mass flow rate was 0.8 kg/second had the best influence for uniformity of temperature. The result showed that this treatment had smallest difference of inside and outside temperature was 0.31-7.81°C and the APD was 3.82%. And by adding 10% iradiation input had the highest influence for uniformity of moisture content. The result showed that this treatment had smallest difference of inside and outside moisture content was 0.14-2.94% wb. and the APD was 1.09%.
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Judul: Preferensi masyarakat Bogor mengenai calon walikota yang akan dipilih pada Pilkada Kotamadya Bogor 2008
Abstrak: Pemilihan Iccpala Daerah (Pilkada) langsung merupaltan sarana pelaksanaan kedaulatan rakyal ditinght pr'opinsi &an kabupatentkolamadya untuk memilih kepala daerah secara langsung. 13ilkada langsuog men~ungkinkan terpilihnya kepata daerah yang sesuai dengan pilihan rakyat. Penclitian ini bcrt~!jt~ant ~ntukm engetahui karakleristik masyarakst Bogor yang akan nieniberikan hnk pi1ihnj.a pacla Piikada ICotamadya I3ogor 2008 darl nicngetahui prel'crensi inasyarakat Bogor rnengcnni cnlotl \valikota yang akan dipilih pitda Pilkada Bogor 2008. Analisis yang dilakukan melip~niU ji Kcbebasnn Khi-Kuadrat, Tabel Konlingcnsi, dan Analisis Korespondensi.
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