Judul: Studi Implementasi Sistem Kendali On-Off Pada In Store Dryer (ISD) Untuk Komoditas Jagung
Abstrak: In Store Drying is a drying method that uses ambient air as the drying medium and usually applied for grain. In Indonesia, although the humidity is relatively high, this drying method can still be applied by using an appropriate control system. In this research, a control system algorithm had been developed based on comparing the potential of ambient air with the air condition inside the ISD. The control system hardware was constructed based on the algorithm and then was tested for two different ambient air conditions. Corn was used as the material being dried. Simulation based on heat and mass balance was also performed in order to obtain the performed of the control system. The control system constructed in this research included a power supply, a control circuit, a parallel port circuit with IC74244, and circuit for sensor SHT75. The control system selected the ambient air used for drying of grain in store dryer. The performance test showed that with the average ambient air temperature of 32,8oC and relative humidity of 51,93%, the system could dry 1201,2 kg of shelled corn from the initial moisture content of 17,61% to 12,37%d.b. within 50 hours while the system could dry 915,0 kg from the initial moisture content of 18,02% to 12,25%d.b. within 40 hours when the average temperature was 31,14oC and relative humidity was 54,16%. The simulation performed showed that by using on-off control system, an amount of 350 kg/m2 shelled corn can be dried from moisture content of 18% to 15%d.b. within 33 hours with energy consumption 175MJ. Without the control system the same amount of the shelled corn the drying time was 68 hours and then the energy consumption was 360MJ.
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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: 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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