Judul: Pemodelan Sistem Termal Dan Simulasi Pada Oven Surya
Abstrak: Penggunaan energi surya sebagai sumber energi untuk memasak perlu dimanfaatkan. Dengan demikian diperlukan pemasak surya (oven surya) yang optimal dengan penyebaran suhu yang seragam pada bagian ruang pemasakan. Sehingga proses pemasakan dapat berlangsung dengan baik. Untuk itu akan dibuat pemodelan sistem termal dari oven surya dan mensimulasikan fenomena fisis yang terjadi dengan pendekatan finite volume menggunakan teknik Computational Fluid Dynamics (CFD). Pemodelan dan simulasi yang dilakukan dapat dijadikan dasar untuk memperoleh disain yang optimal. Model matematika pada sistem termal sudah diperoleh dengan baik. Model diperoleh pada pendekatan lump dan spasial. Model menghasilkan nilai validasi yang cukup baik sebesar 0.826 dengan galat rata-rata sebesar 13.45% dan standar deviasi sebesar 12.46oC pada kondisi kuasi steady state dan 0.772 dengan galat rata-rata sebesar 14.36% dan standar deviasi sebesar 12.29oC pada kondisi unsteady state. Titik fokus untuk pemasakan terletak pada ruang oven dengan ketinggian 33.5 mm dan mendatar pada titik tengah ruang oven. Guna mendapatkan disain yang efisien, pemasakan dilakukan pada titik fokus tersebut. Hasil simulasi menunjukkan pada nilai C =52 mampu mampu memanaskan air sampai 100oC pada iradiasi 600 W/m2 selama 30 menit pada kondisi tempat masak tanpa tutup.
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Judul: Simulasi Numerik untuk Pola Sebaran Suhu Kolektor Surya Pelat Datar Tipe Back-pass Cover Semi Tertutup
Abstrak: Solar energy is abundantly available, so this energy is very potential to be developed, especially in Indonesia. One of the alternative to utilize solar energy is using back-pass flat plate solar collector. The thermal energy produced by the collector can be used for crop drying. In this study, the back-pass flat plate solar collector with semi-closed cover was connected to a drying box and the thermal energy will flow into it. The effect of variation of the length of cover percentage at several tilt angle to the collector performance (temperature distribution and mass flow rate) were investigated experimentally and numerically. Numerical simulation result showed that cover of 60% had adequated to produce the air temperature above 40oC that can be used for drying most of agricultural products. Increasing percentage of cover to 80% or 100% did not improve air temperature significantly. Even the effect would increase collector manufacturing cost. The results of numerical simulations showed that tilt angle 45o had optimum mass flow rate, it was about 0.009 kg/s. Validation with experiment data showed that total error was below 10% and R2 varied from 0.76 until 0.98. Simulation of temperature distribution in drying box showed that temperature varied from 41 oC until 51 oC with error below 10% and R2 varied from 0.93-0.98.
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Judul: Amfibi sebagai satwa peliharaan: Ekspor, Impor dan Perdagangan Domestik
Abstrak: Indonesia has exported amphibian as frozen frog legs (listed since 1969 under fishery product) for consumption and live amphibian (listed since 1983 under reptilian class in forestry product) for pets. There are also live amphibian trading in local level i.e in markets and malls. This research aims to identify amphibian species exported and imported by investigating document from related administration and to identify amphibian species traded in domestic market by observation at Jakarta. Research is primarily conducted by processing quota data taken from Department of Forestry Republic of Indonesia database in Jakarta. Market observation was carried out in 18 locations (3 markets and 15 malls) in Jakarta. I carried out interview with trader and export business, which related to net trading live amphibians for pets. Respondent was choosen using snowball sampling manner. Name of species is written according to Iskandar & Coljin (2000). If there is no such record in the checklist (for example species are from outside Indonesia), then the species name is written according to Frost (2004). There are 56 species from eight families of wild amphibians that have pets quota between 1998-2008. Nineteen species was traded since 1983. The highest export quota is Litoria caerulea (21,37%). Allocation of highest catching quota is for BKSDA Jayapura (20,40%) and BKSDA Papua Barat (18,96%). Four species are included in IUCN Red List categories as vulnerable, among others are Limnonectes macrodon, Meristogenys jerboa, Nyctixalus margaritifer and Rhacophorus margaritifer. The number of amphibians that have export realization are 39 species. Two species of amphibian, Leptobrachium hasseltii and Rhacophorus margaritifer are amphibian species whose been known infected by chytrid fungus in the wild. The biggest species exported is Litoria caerulea (54,34%). Between 1983-1991, the biggest import amphibian for pets from Indonesia (66,13%) is Netherlands. Number of quota was relative stable in the last eight years, where as the number of export realization is more fluctuates. Amphibian species imported and re-exported between 1983-2008 come from Africa, South Asia, Malaysian, Archipelago Oceania, North America, Central America and South America. The number of pet amphibian species traded at domestic market is less than exported. Data showed that Indonesia imports 15 amphibian species between 1983-2008, However I found different species in the market that was unrecorded in the Ministry of Forestry data, which is the Fire Belly Salamander.
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