Judul: Flow type and temperature distribution analysis at standard peak greenhouse using Computational Fluid Dynamics (CFD)
Abstrak: This experiment was analyzed of air flow and temperature distribution in standard peak greenhouse using computational fluid dynamics (CFD) as a basic consideration for air movement design. The method is using three models of greenhouse which modified condition of being slant roof to be 30o and 45o. The dimensions of greenhouse existing were: 12 m in length, 6 m in width, and 5,14 m in height. The floor was made from concrete. Polycarbonate was used as roof of the greenhouse and the wall was use screen as natural ventilation with 1,5 mm2. The results of the analysis showed that during the daytime, air temperature inside greenhouse surrounding the roof increased by the condition of being slant roof is steep. The CFD simulation showed clearly the air flow and temperature distribution in greenhouse. This cause showed the average of error at 00:00 o’clock is 1,44%, at 07:00 o’clock is 1,83%, at 12:00 o’clock is 2,34%, and at 17:00 o’clock is 1,49%. Therefore, it can be used as basic consideration for the modified of slant roof design with respect to low air temperature and uniform air temperature distribution. It was recommended that one of the optimal condition of being slant roof is 30o.
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Judul: Simulation of Temperature Distribution and Airflow Pattern on a Modified Standard Peak Greenhouse Equipped with Mechanical Ventilation Using CFD (Computational Fluid Dynamics).
Abstrak: The application of Computational Fluid Dynamics (CFD) in the agricultural engineering is commonly employed to solve environmental problems of greenhouses and agricultural production facilities. In this research, CFD was used to simulate temperature distribution and airflow pattern on a modified standard peak greenhouse. Climate data and the greenhouse properties (wind speed, solar radiation, relative humidity, environmental temperature, insect screen porosity, radiative surface of roof, etc.) were defined as inputs for the simulation. The effect of insect screens and exhaust fan application to airflow pattern and temperature distribution inside the greenhouse were also investigated and quantified. Results of this research showed that insect screens significantly reduced airflow and increased thermal gradients inside the greenhouse, but exhaust fan performance had less effects on airflow pattern and temperature distribution. Maximum air velocity inside the greenhouse observed near the openings sidewall ventilation and in the middle of greenhouse wind directions were different or the wind spinned (butterfly-like pattern) within the greenhouse. Natural ventilations performed more effectively than mechanical ventilations by using exhaust fans. The CFD model succeded to simulate temperature distribution and airflow pattern of the greenhouse. The realibility test on temperature distribution showed that maximum error of 9.87 % which is smaller than 10 %, and the uniformity coefficient of 98.2 %.
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Judul: Karakterisasi Protein Bisa Ular Kobra Jawa (Naja Sputatrix) Setelah Perlakuan Penjemuran Dan Fotooksidasi
Abstrak: Bisa ular telah diketahui memiliki toksisitas yang menyebabkan kematian sekaligus merupakan sumber hayati yang penting sebagai obat untuk penyembuhan penyakit. Beberapa perlakuan dapat diberikan untuk menghilangkan toksisitas dalam bisa ular. Penelitian mengenai perlakuan penjemuran dan fotooksidasi untuk menurunkan efek toksik bisa ular Naja sputatrix belum dilakukan. Tujuan dari penelitian ini yaitu mengkarakterisasi kandungan protein dan aktivitas toksik pada bisa ular N. sputatrix setelah diberi perlakuan penjemuran dan fotooksidasi. Kadar protein pada bisa ular N. sputatrix yaitu 20.46% (b/v) yang meningkat setelah proses penjemuran, dan menurun setelah proses fotooksidasi. Bisa ular dipisahkan menjadi 5 pita protein utama dengan bobot molekul 14 hingga 108 kDa. Penjemuran selama 6 jam memiliki efek yang sama dengan perlakuan fotooksidasi yaitu menurunkan aktivitas LAAO sebesar 91% dan menghilangkan aktivitas antikoagulasi pada bisa ular, namun kedua perlakuan tersebut memiliki efek yang berbeda pada enzim PLA2 bisa ular. Penjemuran tersebut menurunkan 96% aktivitas PLA2 sedangkan fotooksidasi menghilangkan hampir seluruh aktivitas enzim tersebut (99.8%). Hasil ini menandakan bahwa penjemuran dan fotooksidasi dapat menurunkan aktivitas toksik dari bisa ular, namun tidak mempengaruhi karakter fisik dari kandungan proteinnya.
Keyword: asam L-amino oksidase, fotooksidasi, Naja sputatrix, bisa, fosfolipase A2