Judul: Komposit Polianilina/Perak Nanowires sebagai Elektrokatalis Reaksi Evolusi Hidrogen dalam Medium Netral
Abstrak: Studi mengenai elektrokatalis untuk reaksi evolusi hidrogen (HER) dan evolusi oksigen (OER) sangat diperlukan terkait aplikasinya dalam pengembangan energi terbarukan berbasis hidrogen. Komposit perak nanowires (AgNWs) dengan polianilina (PANI) disiapkan dengan metode polimerisasi radikal dalam larutan matriks kitosan untuk menurunkan ukuran partikel PANI. Komposit disintesis dengan 3 perlakuan yang berbeda, yaitu perlakuan suhu ruang, suhu rendah, dan sonikasi. Aktivitas elektrokatalisis diukur dengan voltammetri penyapuan linear (LSV). Informasi tentang densitas arus pertukaran dan overpotensial sebagai variabel utama pengukuran aktivitas elektrokatalisis diperoleh dari plot tafel pada LSV. Semua komposit dengan perlakuan pada suhu ruang dan dengan sonikasi menunjukkan karakter katodik berdasarkan nilai overpotensialnya yang negatif, sedangkan komposit dengan perlakuan suhu rendah memiliki karakter anodik. Dapat disimpulkan bahwa komposit dengan perlakuan suhu ruang dan sonikasi menunjukkan aktivitas HER dan komposit dengan perlakuan suhu rendah menujukan aktivitas OER.
Keyword: elektrokatalis HER-OER, densitas arus pertukaran, overpotensial, plot tafel, polianilina

Judul: Komposit NiCu Layered Double Hydroxide sebagai Elektrokatalis Evolusi Oksigen
Abstrak: Elektrolisis air merupakan salah satu cara terbaik dalam memperoleh sumber energi yang dapat diperbarui. Salah satu reaksi yang berperan dalam elektrolisis air adalah reaksi evolusi oksigen (OER). Langkah dalam OER mencakup transfer 4 elektron sehingga secara energetika dan kinetika membutuhkan energi yang besar dan katalis untuk mempercepat reaksi. Elektrokatalis yang dikembangkan dalam penelitian ini adalah komposit NiCu layered double hydroxide (LDH) menggunakan metode kopresipitasi. Linear sweep voltammetry memberikan informasi terkait kemiringan Tafel (b) melalui plot hubungan overpotensial dan log (j). Berdasarkan ciri difraksi sinar X, NiCu LDH berhasil terbentuk dengan membandingkan sudut 2 dengan literatur. Parameter uji aktivitas katalitik pada elektrokatalis tersebut memberikan nilai kemiringan Tafel terendah (44.5 mV/dec ) dan overpotensial terendah (465.1 mV/cm2 pada j=10 mA/cm2), serta koefisien transfer muatan tertinggi (1.3359) pada nisbah 2:1 dengan medium NaOH 1.0 M.
Keyword: aktivitas elektrokimia, elektrokatalis, kopresipitasi, NiCu LDH, overpotensial

Judul: Biology and ecology of the buffalo fly, haematobia exigua de meijere (diptera:muscidae)
Abstrak: The life history of the buffalo fly was observed at room temperature of 27°-29.5°C and at a relative humidity of 48-68 percent. The eggs hatched after 17-22 hours, with an average of 18 hours. First instar larvae measured 1.25 + 0.16 mm long and 0.27 + 0.037 mm wide. reach the second larval stage. It took 6-12 hours to the second instar larvae measured 2.676 +0.187 mm long and 0.353 +0.028 mm wide. The second instar took about 12-24 hours to reach the third larval stage. The third instar measured 6.833 + 0.189 mm long and 0.919 + 0.051 mm wide. It took about 2-3 days for the third instar to become pupae. Duration of the pupal stage was about 5-7 days before the adults emerged. Under laboratory condition, the buffalo fly completed its life cycle in 9.5 to 10.5 days, whereas under field condition it took 9-14 days with an average of 10.5 days. The growth ratio which was based on the measurements of the cephalo-pharyngeal skeleton of each instar was 1.797. The preoviposition period was 8-12 days and mating usually occurred on the 6th or 7th day. The longevity of the male was 29 days, whereas it was 32 days in the female. The range of egg production under laboratory condition was between 20-139 per female fly. The belly and hind legs of the carabao were the most preferred habitat either during cloudy and cool dry or shiny and warm day. When the weather was clear and the carabao was in the shade, the flies tended to be more distributed particularly on the shoulder, dewlap, back and horns. The carabaos had relatively fewer Musca sp. and Stomoxys calcitrans than cattle; never the less carabaos had a higher infestation of buffalo fly than cattle. Oviposition occured either during the day or night but the buffalo flies were more active during the night than in the day time. The effect of various lengths of exposure time of manure in relation to the oviposition was profound. observed, the maximum number of the buffalo flies was occurred when the dung was exposed for 30 minutes. With increasing time of exposure the number and variety of insects also increase. It was evident that Sepsidae and psychodidae were the most dominant insects emerging from the dung. The number of buffalo flies also increased with increasing
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