Judul: Simulasi Sebaran Suhu Udara dan Permukaan Lantai Rumah Tanaman dengan Menggunakan Computational Fluid Dynamics (Cfd)
Abstrak: Temperature is one of important factors in plant growing. Distribution of temperature that occurs in the greenhouse should be used as the basic consideration for designing a greenhouse. Floor is one of important governing factors that affect temperature distribution. The air and surface temperature distribution on the floor greenhouse can be simulated by using Computational Fluid Dynamics (CFD). The simulation was applied to a naturally ventilated standard peak greenhouse. Measured floor surface temperature were 26.3–47.7 oC and air temperature at 45 cm above the floor surface were 23.5–39.2 oC. Simulated floor surface temperature were 26.41–39.89 oC and air temperature at 45 cm above the floor surface were 25.43–36.40 oC. Validation of the model had been done by calculating accuration and linear regression analysis. The simulation showed the accuracy 91.18-99.66% at the minimum solar radiation (0 W/m2) and 90.79-99.92% at maximum solar radiation (1,092 W/m2), and resulting a high value of coefficient of determination (0.946-0.947). Results show that the model performed well in simulating the air and surface temperature distribution on the floor of greenhouse, as compared to that of the measured value. It also show that CFD could be used to predict convective heat transfer and airflow pattern on the floor of greenhouse, accurately.
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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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