Judul: Strategi Pengendalian pada Pengeringan Jagung Pipilan yang Memanfaatkan Udara lingkungan
Abstrak: In artificial drying, consumption of thermal energy is about 90%-95% of requirement total energy (Manalu, 1999; Nelwan, 1997). Ambient air drying is a drying method that use unheated air, thus its thermal energy consumption is very low. Indonesia is a tropical country that ambient air condition generally has high relative humidity, however the mean temperature is more than 30oC and the relative humidity is lower than 70%. This condition is potential to dry the corn up to it’s equilibrium moisture content (Me) i.e. 14%. Because of the fluctuative condition, the ambient air doesn’t have potential ability to dry at all. In deep bed dryer, there are various moistures in layers. Therefore, control system based on differences of moisture content in corn layers is needed to flow the potential ambient air -high of air temperature and low relative humidity- and to control the velocity of ambient air flow. The control system consists of detector of temperature and RH by SHT11 and SHT75 sensor, LCD, power supply and zero crossing circuits. The controlling system program was written ‘C language’, and written by Uc51 software 3.48 version, and also has function as compiler to convert ‘C language’’ to file.hex. The controlling strategy compare equilibrium moisture content in layer with the ambient as a hint of round of blower. If ambient Me < Me of the lower layer, the blower flows the maximum flow rate (0.455 m2/s). Contraryly, if Me >Me of the upper layer, the blower won’t flows . And if Me of the lower layer < ambient Me < Me of the upper layer, the blower flows the ambient air with five different levels of flow rate ( 0.398m2/s, 0.347 m2/s, 0.272 m2/s, 0.169 m2/s ,and 0.136 m2/s ) based on the comparation of the third Me. The experiment without control system showed that when the ambient temperature is about 25.7oC - 36oC and average ambient RH is about 55.25% - 97.65%, can dry the corn from average moisture content 20.48% b.k to 16.08% bk in 46.5 hours and consumed electrical energy as much as 4.288 MJ/kg of water evaporated. But, In the experiment with control system with average ambient temperature is about 27.9oC – 40.6oC, and average ambient RH is about 39.47% - 93.43%, the drying process start from average moisture content 20.89% b.k to 16.20% b.k due 10.517 hours and consume electric energy as much as 1.553 MJ/kg of water evaporated. Control Strategy Program worked properly and consumed less electrical energy and drying time process than the experiment without control system.
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Judul: Strategi Pengendalian Pengeringan Jagung Pipil dengan Kadar Air Tinggi yang memanfaatkan Udara Lingkungan
Abstrak: A bed dryer model has been designed and constructed to study control stategy of ambient drying for high moisture content shelled corn. The control strategy developed in this research was based on the diference of moisture content and the moisture content equivalent of ambient air. The action of the control system was the rotational speed of fan regularity to control the air flow rate. The result showed that with at initial moisture content of corn 20% w.b to the final moisture content of 13.61% w.b. drying were accomplided in 69.5 hours and fan turn on for 20.5 hours with the condition rated highest temperature recorded during the drying process is 37.5oC, and thelowest temperature was 28.5C. Average temperature was 29.15oC, and also was obtained that the highest environtmental RH recorded was 94.8% and the lowest RH was 52.4% RH environmental so that the average was 82.83%, and consumed electrical energy around 4.25 kWh or 15.3 Megajoules. From that equation, assumed energy consumption per kilograms of water evaporated was 4.37 MJ. From the above result the controller system in this dryer is working properly as per design.
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Judul: Posisi Filogenetik Kura-Kura Carettochelys Insculpta  (Reptillia: Testudinata)
Abstrak: Carettochelys insculpta is an endemic freshwater turtle of southern Papua and northern Australia. Phylogenetic position of this turtle is remain unresolved until now. Most of the research conducted show close relationships of C. insculpta and members of Trionychidae family. However, some of the research show distance between C. insculpta and members of Trionychidae family. This research is conducted to analyze phylogenetic relationship between C. insculpta and other members of Testudinata using 12S rRNA, 16S rRNA, and both gene as markers. DNA samples were obtained from three different organisms of C. insculpta. Two species used as outgroups were Alligator mississippiensis and Iguana iguana. Phylogenetic analysis was carried out using Neighbor-Joining method with Felsenstein 1981 (F81) modeltest. A polytomy tree of Testudinata was produced by using 12S rRNA gene. However, analysis using 16S rRNA and both genes as markers confirmed that C. insculpta was located between the Chelonidae and the Trionychidae family.
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