Judul: Analisis Kecepatan Aliran Air Pada Filter Flow Up dan Filter Flow Down
Abstrak: Penggunaan system Recirculating Aquacultur System (RAS) diterapkan di daerah yang memiliki sumber air yang terbatas. Sistem tersebut merupakan konsep pemanfaatan air bersih yang disaring dan diresirkulasi untuk berbagai jenis manfaaat salah satunya untuk akuakultur. Aliran air yang terdapat pada sirkulasi juga memiliki kecepatan alir yang mengikuti bentuk sistem. Penelitian ini bertujuan mendapatkan analisa kecepatan aliran sistem filtrasi flow up dan flow down. Pengukuran pada pipa yang besar, mengakibatkan kecepatan aliran air juga semakin besar, kemudian skema dengan bentuk pipa flow up mendapatkan nilai debit aliran air yang lebih besar dibandingkan skema bentuk pipa flow down. Filter yang digunakan juga berpengaruh terhadap nilai kecepatan aliran air dimana nilai kecepatan alirnya lebih besar dibandingkan sebelum menggunakan filter. Penelitian ini diharapkan dapat memberikan referensi bagi pemilihan jenis filter flow up dan flow down, pemilihan ukuran pipa untuk skema resirkulasi air pada akuakultur, dan cara menganalisis debit pompa terhadap kesesuaian skema sirkulasi kolam ikan., The use of the Recirculating Aquaculture System (RAS) is applied in areas that have limited water sources. This system is a concept of using filtered and recirculated clean water for various types of benefits, one of which is for aquaculture. The water flow contained in the circulation also has a flow rate that follows the shape of the system. This study aims to obtain an analysis of the flow velocity of the flow up and flow down filtration systems. Measurements on large pipes result in a greater velocity of water flow, then the flow-up pipe scheme obtains a greater water flow rate than the flow-down pipe scheme. The filter used also affects the value of the velocity of the water flow where the value of the flow rate is greater than before using the filter. This research is expected to provide a reference for selecting flow up and flow down filter types, selecting pipe sizes for water recirculation schemes in aquaculture, and how to analyze pump discharge for the suitability of fish pond circulation schemes.
Keyword: Aquaculture, Discharge, Filters, Flow Up and Flow Down Pipes, Water Flow Velocity

Judul: Isoterm Adsorpsi pada Filter Karbon Aktif dengan Pengaruh Model Multimedia Filter pada Recirculating Aquaculture System (RAS)
Abstrak: Teknik pengolahan air yang dapat digunakan untuk menghasilkan kualitas air yang baik bagi budidaya ikan koi salah satunya adalah dengan penerapan Recirculating Aquaculture System (RAS). Penelitian ini bertujuan untuk menganalisis kesesuaian adsorpsi dari multimedia filter dan karbon aktif yang digunakan dengan model isoterm adsorpsi. Penelitian dilakukan dengan mengukur konsentrasi parameter amonia, nitrit, TSS, alkalinitas, suhu, pH, dan DO pada kualitas air dengan menerapkan beberapa variasi pada ketebalan dan debit multimedia filter. Variasi debit yang digunakan antara lain 45 L/menit dan 22,5 L/menit, serta variasi ketebalan media zeolite yang digunakan antara lain 30 cm, 60 cm, dan 90 cm. Kemudian melakukan analisis isoterm adsorpsi dengan menggunakan model isoterm adsorpsi langmuir, freundlich, temkin, halsey, dan khan. Kualitas air influen dan efluen pada unit filter karbon aktif menunjukan penurunan konsentrasi amonia, nitrit, dan TSS. Dari beberapa variasi yang digunakan, variasi ke-5 (ketebalan zeolite 90 cm dan debi 45 L/menit) merupakan variasi yang terbaik. Model isoterm adsorpsi khan merupakan model yang paling sesuai dikarenakan memiliki tingkat kesesuaian regresi yang paling tinggi., One of the water treatment techniques that can be used to produce good water quality for koi fish farming is the application of the Recirculating Aquaculture System (RAS). This study aims to analyze the adsorption suitability of the multimedia filter and activated carbon used with the adsorption isotherm model. The research was conducted by measuring the concentration of ammonia, nitrite, TSS, alkalinity, temperature, pH, and DO parameters on water quality by applying several variations on the thickness and discharge of the multimedia filter. Variations in the discharge used included 45 L/min and 22.5 L/min, and variations in the thickness of the zeolite media used were 30 cm, 60 cm, and 90 cm. Then analyze the adsorption isotherm using the Langmuir, Freundlich, Temkin, Halsey, and Khan adsorption isotherm models. The quality of the influent and effluent water in the activated carbon filter unit showed a decrease in the concentration of ammonia, nitrite, and TSS. Of the several variations used, the fifth variation (zeolite thickness 90 cm and debi 45 L/min) is the best variation. Khan adsorption isotherm model is the most suitable model because it has the highest level of regression suitability.
Keyword: Budidaya, karbon aktif, RAS, variasi

Judul: Lejeuneaceae Subfamily Ptychanthoideae (Hepaticae) in  West Java
Abstrak: Subfamily Ptychanthoideae of the family Lejeuneaceae (Hepaticae) in West Java is still poorly known. Publications on this subfamily are out of dated and written in the 19th or early of 20th century. The last taxonomic treatment of Ptychanthoideae of West Java was in 1933, many species names have changed since then. Studies on Ptychanthoideae of West Java are urgently needed. Studies on the Ptychanthoideae were based on the specimens collected from West Java. A total number of 361 of specimens deposited in the Herbarium Bogoriense (BO), Herbarium Biotrop (BIOT), Gottingen Herbarium (GOET) and Bangi Herbarium (UKMB) were examined, those are old and several recent specimens collected in West Java. Recent collections were made from Telaga Warna, Ciater, Gunung Halimun Salak National Park, Cibodas Botanical Garden, Bodogol Education Center and Conservation (Gunung Gede Pangrango National Park), University of Indonesia Campus Depok, including several collections from Banten Province. Twenty four species of Lejeuneaceae subfamily Ptychanthoideae are known from West Java, belonging to 8 genera namely Acrolejeunea (Spruce) Schiffn. (2 species), Archilejeunea (Spruce) Schiffn. (1 species), Lopholejeunea (Spruce) Schiffn. (10 species), Mastigolejeunea (Spruce) Schiffn. (3 species), Ptychanthus Nees (1 species), Schiffneriolejeunea Verd. (1 species), Spruceanthus Verd. (2 species) and Thysananthus Lindenb. (4 species). Two new records of Ptychanthoideae: Mastigolejeunea indica Steph. and Thysananthus minor Verdoorn are reported for Java. A determination key to the species is presented including their descriptions and illustrations.
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