RANCANG BANGUN MICROBUBBLE GENERATOR TIPE ORIFICE DENGAN PIPA POROUS UNTUK AERASI KOLAM IKAN

Indonesia merupakan negara kepulauan dengan potensi laut yang besar. Hal ini membuat Indonesia memiliki potensi produksi akuakultur terbesar di dunia. Tantangan besar akuakultur yaitu cara meningkatkan produktivitas untuk suplai pangan, namun dengan penggunaan sumber air dan lahan yang lebih efisien. Hal tersebut tentu perlu didukung oleh pengembangan teknologi yang hemat energi serta kualitas air yang tetap terjaga pada kondisi ideal. Pada sektor perikanan, kualitas air merupakan faktor utama untuk perkembangan budidaya ikan. Penelitian ini mengkaji kapabilitas dari Microbubble Generator (MBG) tipe orifice dengan pipa porous pada aerasi kolam ikan. Nilai Dissolved Oxygen/DO merupakan indikator kerja yang digunakan untuk menguji kapabilitas MBG. Pada penelitian ini diperoleh alat uji MBG tipe orifice dengan pipa porous berdimensi overall 0,5m x 0,5m x 1,5m, diameter lubang porous 0,3mm, diameter nozzle 20mm, pipa ¾ inch PVC, kapasitas aliran 430liter/menit, head tekanan 18m. Hasil pengujian pada ukuran kolam ikan 10m x 2,3m x 1m (tinggi air 85cm) dengan air standar (tanpa ikan), untuk setiap kedalaman (30cm dan 60cm) peningkatan harga DO sebanding dengan peningkatan diameter orifice. Pengaruh jarak semburan terhadap harga DO adalah berbanding terbalik, semakin jauh jarak semburan akan menurunkan harga DO. Pada variasi kedalaman, harga DO berada pada kisaran harga yang sama yaitu 8,15 ppm sampai dengan 8,16 ppm, hal ini menunjukkan bahwa pengaruh kedalaman tidak menunjukkan perbedaan harga DO yang cukup besar. Harga DO yang terukur dari hasil pengujian dengan variasi orifice dan kedalaman adalah cukup sesuai untuk aerasi kolam ikan, karena harga DO untuk air dengan ikan sekitar 2-4 ppm.

A rare case of a systemic-to-pulmonary veno-venous connection: a pause during development of pulmonary and systemic venous separation

A 45-year-old man with dyspnoea and palpitations exhibited a unique systemic-to-pulmonary veno-venous connection on preoperative CT images. A window of 31.5-mm diameter was evident between the superior caval vein and the middle pulmonary vein, which was normally connected to the left atrium via a 30-mm-diameter orifice. The atrial septum was intact.

A New Design for Variable Diameter Orifice Mechanism

Variable diameter orifice is required in many applications e.g. smokestacks coal furnaces, liquid dispensing machines, wall fans, gas handling systems, pipes, vacuum chambers air valves, fluid control systems, ventilation systems, ducts, spot lights, holes of golf sports, photography nozzles, solid free fabrications and vacuum valves [1–17]. The need for variable diameter is to control the medium transfer through the orifice. In this abstract, a new design for a variable diameter orifice is introduced. Designing a variable diameter orifice is a challenging problem due to the need of circular geometry of the orifice opening. Many designs have been conducted to design a variable diameter orifice. However, the proposed designs are either have non circular opening or require a bulky size mechanism. In the proposed design, simplicity, size and actuation are our main concern.

Expansion Factor Tests in a 75 mm Diameter Orifice Meter Tube

This paper presents new experimental data for orifice meter expansion factor tests flowing natural gas through a 75 mm (3-inch) diameter orifice meter tube for values of the orifice diameter ratio (β) between 0.60 and 0.75. The tests were performed in the Low Pressure Loop (LPL) of the Metering Research Facility (MRF) at Southwest Research Institute (SwRI). The new data complement previously reported results for 100 mm (4-inch) and 150 mm (6-inch) meter tubes for β values between 0.20 and 0.60.

Orifice Meter Expansion Factor Experiments

This paper presents new experimental data for orifice meter expansion factor and compares the results with previous data and accepted expansion factor correlations. The tests were performed in the Low Pressure Loop (LPL) of the Metering Research Facility (MRF) at Southwest Research Institute (SwRI) flowing natural gas through 100 mm (4-inch) and 150 mm (6-inch) diameter orifice meter tubes for values of the orifice diameter ratio (β) between 0.25 and 0.60. The results for expansion factor, within the β range of the tests, are in good agreement with previous data reported by Murdock and Foltz (1953) flowing steam in a 100 mm meter tube and by Seidl (1995) flowing air in a 50 mm (2-inch) diameter meter tube.