Judul: Methane Gas Flux Analysis from Biogas Sheep Manure and Combination of Sheep and Beef Cattle Manure
Abstrak: Sektor Peternakan berkontribusi sebagai penyumbang emisi gas rumah kaca (GRK) seperti metana (CH4), karbon dioksida (CO2), dan dinitrogen oksida (N2O). Tujuan penelitian adalah menganalisis fluk gas CH4 dari biogas kotoran domba dan kombinasi kotoran domba serta sapi potong. Perlakuan meliputi 100% kotoran domba (T1) dan kombinasi 15% kotoran domba serta 85% kotoran sapi potong (T2) dengan dua ulangan untuk setiap perlakuan. Analisis TS, VS, C, N, dan C/N rasio setiap perlakuan diperoleh dari kotoran ternak dan substrat biogas pada awal pengamatan setiap perlakuan. Pengukuran fluk CH4 dan CO2 dilakukan setelah sepuluh hari memasukkan substrat ke dalam digester dengan interval tiga hari sekali selama empat kali pengukuran. Hasil penelitian menunjukkan bahwa nilai TS pada perlakuan T1 dan T2 berbeda secara signifikan (p<0,05). Nilai pH rata-rata pada perlakuan T1 adalah 6,7 dan pada perlakuan T2 adalah 6,6. Nilai rata-rata fluk gas CH4 T1 adalah 40 mgCH4/m2/day dan 107,13 mgCH4/m2/day pada T2 dan kedua perlakuan menunjukkan perbedaan secara signifikan (p<0,05). Komposisi substrat sangat menentukan kandungan TS dan nilai pH dalam fermentasi anaerob produksi biogas., The livestock sector contributes to greenhouse gas (GHG) emissions such as methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O). The study aimed to analyze CH4 flux from the biogas of sheep manure and the combination of sheep and beef cattle manure. The treatments included 100% sheep manure (T1) and a combination of 15% sheep manure and 85% beef cattle manure (T2) with two replications for each treatment. Analysis of TS, VS, C, N, and C/N ratio was obtained from livestock manure and biogas substrate at the beginning of the observation. Measurements of flux CH4 and CO2 were made after ten days of feeding the substrate into the digester at intervals of once every three days for four observations results showed that the T1 and T2 treatment TS values were significantly different (p<0.05). The average pH value in the T1 treatment was 6,7 and the T2 treatment was 6.6. The mean value of CH4 T1 flux was 40 mgCH4/m2/day and 107.13 mgCH4/m2/day in T2 and both treatments differed significant (p<0.05). The composition of the substrate largely determines the TS content and pH value in the anaerobic fermentation of biogas production.
Keyword: biogas, gas rumah kaca, kotoran domba, kotoran sapi potong, beef cattle manure, biogas, greenhouse gases, sheep manure

Judul: Biogas Production from A Combination of Sheep and Dairy Cattle Manure
Abstrak: Tingginya populasi domba dan sapi perah di Jawa barat akan menghasilkan kotoran ternak yang berlimpah. Kotoran ternak dapat mencemari lingkungan jika tidak dikelola dengan benar. Biogas dapat diproduksi dari kotoran domba dan kotoran sapi perah melalui fermentasi anaerob. Penelitian bertujuan menganalisis produksi biogas dari kombinasi kotoran domba dan kotoran sapi perah. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) dengan tiga perlakuan dan tiga kali ulangan tiap perlakuan. Perlakuan pada penelitian ini yaitu D100S0 (100% kotoran domba dan 0% kotoran sapi perah), D50S50 (50% kotoran domba dan 50% kotoran sapi perah), dan D25S75 (25% kotoran domba dan 75% kotoran sapi perah). Nilai TS akhir setelah fermentasi anaerobik semua perlakuan berbeda nyata (P<0,05). Volume biogas dan lama nyala api perlakuan D50S50 berbeda nyata daripada D100S0 dan D25S75. Suhu harian biogas mengalami fluktuasi antara 2629 °C. Nilai pH pada rentang 6,698,13 melebihi kondisi netral. Penggunaan kotoran domba sebagai biogas menghasilkan warna nyala api biru sedikit kemerahan. Hasil penelitian menyimpulkan bahwa kotoran domba berpotensi menghasilkan biogas., The high population of sheep and dairy cattle in West Java will produce high manure production. Animal manure can pollute the environment if not managed properly. Biogas can be produced from sheep manure and dairy cattle manure through anaerobic fermentation. This study aimed to analyze biogas production from a combination of sheep and dairy cattle manure. This study used a completely randomized design (CRD) with three treatments and three replications for each treatment, including D100S0 (100% sheep manure and 0% dairy cattle manure), D25S75 (25% sheep manure and 75% dairy cattle manure), and D50S50 (50% sheep manure and 50% dairy cattle manure). The final TS after anaerobic fermentation differed for all treatment (P<0,05). The biogas volume and flame duration of D50S50 differed (P<0,05) than D100S0 and D25S75. The daily biogas temperature fluctuates between 26-29 °C. The pH value in the range of 6,69-8,13 exceeded neutral conditions. The use of sheep manure as biogas produces a slightly reddish-blue flame. To conclude, sheep manure has the potential to produce biogas.
Keyword: biogas, kotoran domba, kotoran sapi perah

Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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