Judul: Keanekaragaman Jenis Ikan Air Tawar di Sungai-sungai yang Berasal dari Gunung Salak
Abstrak: Approximately 50 river flow from Salak Mountain passed Bogor and Jakarta is Ciliwung and Cisadane river. Sampling period from January until March 2012, on 11 sampling sites of 7 rivers. We found 6 ordo, 9 family, and 13 species of fish. Ten species are native fish and 3 species are introduction fish. Cypriniformes are dominant ordo found at all sampling sites. Ordo Cypriniformes with 2 family, is Cyprinidae (Barbodes gonionotus, Rasbora aprotaenia, Puntius sp., and Puntius binotatus) and Balitoridae (Nemacheilus fasciatus). Ordo Siluriformes with 3 family, is Clariidae (Clarias teijsmanni), Loricariidae (Hypostomus plecostomus), and Sisoridae (Glyptothorax platypogon). Ordo Perciformes that found one family Channidae (Channa striata), Ordo Beloniformes found one family Hemiramphidae (Dermogenys pusilla), Ordo Synbranchiformes is family Mastacembelidae (Macrognathus maculatus), Ordo Cyprinodontiformes with 2 species (Xiphophorus helleri and Poecilia reticulata).
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Judul: Keanekaragaman Jenis Udang Air Tawar di Sungai-Sungai yang Berasal dari Gunung Salak
Abstrak: Freshwater prawn is a crustacean that has an important role in maintaining the balance of freshwater ecosystems. Biodiversity of freshwater prawn research was conducted in the rivers where upstream on Salak Mountain, Bogor, West Java. This study was aimed to find out information on species biodiversity of freshwater prawn in rivers where come from Mount Salak. Sampling stations were 11 points in the rivers where upstream on Mount Salak by road sampling. There was three species of freshwater prawns, namely Macrobrachium lanchesteri (3 specimens), M. empulipke (6 specimens), and M. sintangense (50 specimens). M. sintangense, most commonly found species, mainly found in the slow water with mud substrate. M. empulipke found in rocky habitats with faster water flow, while M. lanchesteri alien species that was found in swift water stream. This species can survive in extreme conditions and could be a superior competitor for local spesies
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Judul: Gamma Ray Irradiation on UHMWPE and HDPE to Increase Tibial Tray Mechanical Properties
Abstrak: Ultrahigh molecular weight polyethylene (UHMWPE) is a polymer that is widely used in the manufacture of tibial tray, but it is very expensive. Therefore, high density polyethylene (HDPE) was developed for the manufacturing of tibial tray because the price is lower and has similar properties to UHMWPE. HDPE was made by two methods, namely hot pressing method and heating method, but UHMWPE wass made only by hot pressing method. Tibial tray film of HDPE and UHMWPE from both methods were irradiated with various doses of gamma rays 0, 100, 200, 300 and 500 kGy. The polymers were analyzed for surface microstructure, hardness , tensile strength, elongation at break percentage, and degree of crystallinity. The higher the dose of irradiation the higher the hardness and the degree of crystallinity, but not for the tensile strength and elongation at break percentage. Both polymers were not able to increase mechanical properties in those irradiation doses range because crosslink formation is inhibited by the presence of oxygen that causes chain scission. HDPE hardness enhancement by hot pressing method was close to
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