Judul: Simulasi distribusi suhu dan pola aliran udara dalam rumah tanaman tipe modified arch menggunakan computational fluid dynamics
Abstrak: In this research, the effect of wind speed on the natural ventilation of a modified arch greenhouse was analysed by computational fluid dynamics (CFD), using the commercial software SolidWorks of 2010. The objectives of this research were to understand the natural ventilation on the greenhouse and develop a simulation of temperature distribution and the airflow pattern on the modified arch greenhouse. The experiment was carried out in a modified arch greenhouse equipped with both top and side ventilations. Climate data and greenhouse characteristics were used as inputs and boundary condition to develop a simulation model. Two-dimensional simulation in a steady state with the condition of no wind speed (0.0 m/s), moderate wind speed (0.5 and 0.6 m/s) and high wind speed (1.8 m/s) were carried out. The wind speed through the insect-proof screen was simulated as a flow through porous media. The CFD model has succeded in predicting the temperature distribution and airflow pattern of the greenhouse. The result of the model showed that the greenhouse has a gradient temperature vertically and the natural ventilation works effectively. It is proved that a small error percentage of difference temperatures between the simulation result and the observed data (less than 8%) was obtained. The coefficient variation was also small (0.12), with the coefficient of uniformity of 89.76%.
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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: Isolasi komponen hemotoksin bisa ular kobra (Naja naja sputatrix)
Abstrak: Elisa ular adalah racun yang diproduksi oleh kelenjar bisa dan digunakan ular untuk mempertahankan dinat mencari mangsa. Bisa ini merupakan campuran dari berbagai komponen. Enzim adalah kompoth utama selain air. Enzim pada bisa ular sangat beragam jenis dan fungsinya. Fosfolipase dan arginin ipadase adalah enzim yang sering terdapat dalam bisa ular dan telah digunakan pada penanganan penyak seperti trombosis Penttian ini bertujuan mengisolasi komponen dari bisa ular kobra dan mengujinya menggunakan sel darah merah sapi 4% untuk aktivitas hemolisis dan bekuan fibrin sapi untuk aktivitas fibrinolisis. Uji aktivitas dilakukan terhadap ekstrak kasar dan fraksi kolom bisa ular. Fraksi kolom diperoleh dari pemurutan ekstrak kasar menggunakan kromatografi filtrasi gel (Sephadex G-75) untuk memperoleh fraksa paksu dengan serapan tertinggi pada A. 280 nm. Ekstrak kasar dan fraksi kolom dengan serapan tertinggi dilakukan pengukuran kandungan protein, Fraksi aktif hasil uji aktivitas selanjutnya ditentukan berat molekulnya (BM) dengan elektroforesis SDS PAGE. Basaglar kobra merupakan cairan pekat berwarna kuning dengan kadar air 71.45%. Dari hasil uji aktivitas diperoleh bisa ular hanya memiliki aktivitas hemolisis sel darah merah sapi secara langsung. Aktivitas ini ditunjukkan oleh fraksi kolom nomor 15 dan 16 tetapi tidak dalam ekstrak kasar. Penurunan konsentrasi ekstrak kasar tidak mempengaruhi terhadap adanya aktivitas hemolisis. Hal ini diduga karena mungkin terdapat inhibitor dalam ekstrak kasar bisa. Inhibitor memiliki BM yang berbeda dengan enzim hemalisis sehingga dapat dipisahkan menggunakan filtrasi gel. Berdasarkan hasil elektroforesis diperolch enzim bemolisis terdapat dalam ekstrak kasar dan tersebar pada fraksi kolom nomor 15 dan 16 dengan BM sekitar 27300 Da
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