Judul: Kinerja Inhibitor Korosi Zink bis(disetilditiofosfat) terhadap Logam Cu dengan Teknik Polarisasi Potensiodinamik
Abstrak: Zink dialkilditiofosfat (ZDTP) telah digunakan sebagai aditif pelumas automotif dengan beberapa manfaat di antaranya sebagai antiaus, antioksidan, dan inhibitor korosi. Senyawa ZDTP dengan alkil rantai panjang, memiliki kestabilan termal yang tinggi dan memberikan kinerja inhibisi korosi yang lebih baik dibandingkan dengan alkil rantai pendek dan bercabang. Rendemen sintesis Zink bis(disetilditiofosfat) diperoleh sebesar 87%. Pengukuran aktivitas Zink bis(disetilditiofosfat) dengan teknik polarisasi potensiodinamik menghasilkan efisiensi inhibisi terhadap korosi sebesar 75% pada konsentrasi larutan sampel 3.0%, dengan perubahan laju korosi pada logam tembaga dari 17.20 mm/tahun ke 4.30 mm/tahun. Spontanitas korosi dihambat dengan adanya ZDTP16, ditunjukkan oleh perubahan nilai energi bebas Gibbs dari 72.15 kJ mol-1 menjadi 87.53 kJ mol-1 dan energi aktivasi naik dari 51.76 kJ mol-1 ke 71.60 kJ mol-1 yang menunjukkan terjadinya penurunan laju reaksi korosi.
Keyword: efisiensi inhibisi, kinetika, laju korosi, termodinamika, zink bis(disetilditiofosfat)

Judul: Sintesis Zink Diisoamilditiofosfat pada Medium Heptana dan Karakterisasi Kinerja Inhibisinya terhadap Korosi Logam Tembaga yang Diukur secara Polarisasi Potensiodinamik
Abstrak: Zinc dialkyldithiophosphates (ZDTP) compound is known as a lubricant additive and has many functions, one of which is as anti-corrosion. ZDTPi was synthesized in 2 steps. The first step was formation of intermediates so called dialkyldithiophosphates acid (ADTP) as resulted from the reaction between diphosphorus pentasulfide (P2S5) and isoamyl alcohol. The second step was addition of metal oxide, ZnO. ZDTPi performance as an anti-corrosion was measured by potentiodynamic polarization technique. The inhibiton effectiveness of ZDTPi to metal Cu reached 98.77% in the 3% concentration of inhibitor solution. Thermodynamic parameter showed a decreasing spontaneity reaction in the presence of inhibitor. The activation energy increased due to the increasing inhibitor addition as indicated by the increasing minimum energy of reaction.
Keyword: Bogor Agricultural University (IPB), zink dialkyldithiophosphates, thermodynamic, potentiodynamic polarization, dialkyldithiophosphates acid, anti-corrosion

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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