Judul: Keanekaragaman dan Distribusi Gastropoda dan Bivalvia (Moluska) di Muara Karang Tirta, Pangandaran
Abstrak: Karang Tirta estuary is an estuarine zone located in Pangandaran, West Java. Substrate of the area was dominated by coarse sand and its salinity ranges from 10-25 ‰. The aim of the reaserch was to know the diversity and distribution of gastropod and bivalve in the estuary of Karang Tirta, Pangandaran and environmental factors affecting them. Samples of molluscs were collected from 3 stations choosen randomly by using quadrat method. Seventeen species were found in the study sties, 12 species belong to gastropod and 5 species of bivalve. The highest Importance Value Index (IVI) among the species was observed on Tellina radiata with 47.449 %. The lowest IVI was observed on four species belong to gastropod and bivalve with 1.949 %. The diversity index (H') ranged from 0.536 to 2.429, the evenness index (E) was from 0.189 to 0.857, and the dominant index (C) was from 0.001 to 0.037. The highest diversity index (H’ = 2.429) was found at station 2 and the lowest (H’ = 0.536) was at station 1. The similarity ranged from 0.235 to 0.522. The distribution patterns of molluscs occured mostly in clumps (Id > 1).
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Judul: Keanekaragaman dan Distribusi Bivalvia dan Gastropoda (Moluska) di Pesisir Glayem Juntinyuat, Indramayu, Jawa Barat
Abstrak: There are several species of molluscs from bivalves and gastropods living in the coastal area of Glayem, Indramayu, West Java. They are used by people for animal feed ingredients, craft materials and other economic activities. The aims of the research were to study diversity and distribution of molluscs in the coastal area and influencing abiotic factors. The research was conducted on January-May 2012. Mollusc samples were collected from 3 stations randomly by using quadrat transect method from the coast line to the reef edge. Generally, the water quality in the coastal of Glayem is fair good, but the ammonia level at all three stations exceeded the standard quality. We found 15 species; 6 species belongs to bivalve, and 9 species belongs to gastropod. The highest Important Value Index (IVI) was showed by Donax incarnatus with 51.28%. The lowest IVI of 1% was displayed by three species of molluscs from class gastropod. The diversity index (H’) ranged from 1.17-1.41, the Evenness index (E) ranged from 0.43-0.52, the dominancy index (C) at each stations of 0.01. The highest density of bivalve at station 3 was 16.4 ind/m2, and the highest density of gastropod at station 1 was 8 ind/m2. The highest Similarity index found in station 2 and 3 was 0.875. Meanwhile, the distribution of 11 species of molluscs was clump and the other 4 species was distributed randomly.
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Judul: Pembuatan Film Tipis Cu2ZnSnS4 sebagai Lapisan Penyerap Cahaya pada Sel Surya Menggunakan Metode Elektrodeposisi
Abstrak: Thin film of Cu2ZnSnS4 (CZTS) is an alternative semiconductor used as light absorber layer on solar cell. CZTS can replace silicon that commonly used as commercial semiconductor. The advantage of using CZTS as absorber layer is due to the abundance of its chemical composer on earth, and its high value of absorption coefficient. The absorber layer was made by using electrodeposition method on ITO glass substrates. The films were deposited at room temperature using potentiostatic mode with a potential of –1.05 V for 30, 45, and 60 minutes. After that, the films were annealed at two different temperatures, 180 ºC and 500 °C, for 45 minutes in N2/H2S atmosphere. Based on X-ray diffraction analysis, the polycrystalline thin film obtained fall into kesterite crystal phase. This type of crystal was obtained when the CZTS was annealed at 500 °C in H2S/N2 atmosphere. The value of optical band gap energy for the CZTS thin film was 2.2 eV with the film thickness about 1.228–6.366 μm. The sample of CZTS with electrodeposition time of 45 minutes and annealing temperature of 500 °C showed the best result and in conformity with absorber layers criteria for solar cells.
Keyword: semiconductor, ITO glass, CZTS thin film, electrodeposition