Judul: Simulasi dan Uji Performansi Konsentrator Surya dan Penukar Panas pada Alat Pengering Efek Rumah Kaca (ERK) Hybrid
Abstrak: A GHE (green house effect) hybrid dryer using solar concentrator as its additional heater has been developed. A simulation and performance test was performed in order to know the contribution of concentrator and heat exchanger as source of thermal energy in dryer. The simulation was based on the heat balance of each system’s component which is solved numerically. Method used in this test was consisted of seven treatment that involving collector tank, heat exchanger, and solar concentrator. Result showed that concentrator could increase water temperature with mass 25 kg for 420 minutes from 30.9 oC to 42.7 oC at average solar energy absorption of 762.8 W/m2. Temperature between dryer room temperature and ambient temperature was 8.6 oC, while night time tests with dryer heater in collector tank resulted difference between dryer room temperature and ambient temperature at 6.3 oC. However, utilization of solar concentrator in this GHE dryer was less efficient due to its low capability to increase temperature. The temperature distribution simulation could described the real condition which in shown by be R2 value of simulation test of concentrator, heat exchanger, collector tank and concentrator’s integrated system were 0.5787, 0.9691, 0.9963 and 0.9762 respectively.
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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: Molecular Systematics of Tree Frog Nyctimystes infrafrenatus infrafrenatus (Tyler 1971) from Papua and Moluccas
Abstrak: Nyctimystes infrafrenatus memiliki permasalahan taksonomi yang cukup kompleks. Spesies ini pertama kali dideskripsikan dengan nama Hyla infrafrenata. Kemudian berdasarkan karakter morfologinya spesies ini dikelompokkan ke dalam genus Litoria dan lebih dikenal dengan nama Litoria infrafrenata namun hasil analisis filogenetika molekuler menempatkan spesies ini pada clade Nyctimystes. Nyctimystes infrafrenatus memiliki dua subspesies yaitu Nyctimystes infrafrenatus infrafrenatus dan Nyctimystes infrafrenatus militarius. Subspesies N. infrafrenatus militarius memiliki distribusi yang terbatas pada Kepulauan Bismarck, Papua New Guinea sedangkan N. infrafrenatus infrafrenatus distribusinya mencakup wilayah utara Sulawesi, Kepulauan Maluku, Pulau Timor, Papua, Australia hingga Kepulauan Solomon. Distribusi yang luas tersebut dapat memunculkan fenomena kriptik spesies. Populasi spesies ini di wilayah Indonesia mewakili dua subregion zoogeografi yang memiliki sejarah pembentukan wilayah yang berbeda yaitu Papua dan Wallacea. Lautan merupakan barrier utama distribusi hewan amfibi karena rendahnya toleransi amfibi terhadap salinitas. Hal ini menimbulkan kemungkinan bahwa N. infrafrenatus infrafrenatus populasi Maluku berbeda dari populasi Papua. Penelitian sebelumnya tentang morfometrik menunjukkan adanya perbedaan ukuran kaki belakang individu betina antara populasi N. infrafrenatus infrafrenatus Papua dan Maluku. Temuan tersebut perlu ditelusuri lebih lanjut dengan pendekatan molekuler. Penelitian ini bertujuan untuk mengevaluasi sistematika N. infrafrenatus infrafrenatus dari Papua dan Maluku. Penanda genetik yang digunakan pada analisis molekuler adalah sekuens gen 16S rRNA. Hasil pensejajaran sekuens ini digunakan untuk rekonstruksi pohon filogenetik, mengestimasi waktu divergensi dan jarak genetik kedua populasi tersebut. Hasil rekonstruksi pohon filogenetik menempatkan semua sampel N. infrafrenatus infrafrenatus pada satu clade monofiletik (MLBS 99%, BPP= 100%). Clade ini kemudian membentuk dua subclade yaitu subclade A yang terdiri atas sampel-sampel dari Papua dan Australia (subclade Papua) serta subclade B yang terdiri dari sampel-sampel Halmahera dan Ternate (subclade Maluku). Hasil estimasi waktu divergensi menunjukkan bahwa kedua subclade tersebut mulai terpisah sejak 6.03 juta tahun lalu (jtl). Jarak genetik antara kedua subclade (2,3,- 4,2%) berada pada threshold beda spesies 3%. Sampel Australia dan populasi Papua mewakili “the true” N. infrafrenatus sedangkan populasi Maluku dengan jarak genetik 3,9-4,2% dengan sampel Australia terindikasi kuat secara genetik merupakan spesies yang berbeda. Berdasarkan artikel 23 ICZN, nama Nyctimystes tennuigranulatus dapat digunakan terutama untuk populasi Maluku bagian utara. Analisis lebih lanjut secara morfologi, akustik dan ekologi yang melibatkan sampel dari Ambon diperlukan untuk menentukan status taksonomi populasi Maluku secara menyeluruh.
Keyword: 16S rRNA, Moluccas, molecular systematics, Nyctimystes, Papua