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: Analysis of Methane Gas Fluk in Heifer Manure Affected by The Different Level of Feeding Ratio
Abstrak: Subsektor peternakan sapi perah menghasilkan produk susu namun berpotensi memberikan dampak negatif terhadap lingkungan, salah satunya adalah peningkatan emisi gas metana (CH4) dari kotoran ternak. Manajemen pemberian pakan merupakan salah satu strategi mitigasi emisi CH4. Tujuan dari penelitian ini adalah menganalisis fluk gas CH4 dari kotoran sapi perah dara yang dipengaruhi oleh rasio pakan dengan kadar bahan kering yang berbeda. Penelitian ini menggunakan model rancangan bujur sangkar latin (3x3) dengan tiga ekor ternak dara dan tiga perlakuan rasio pakan yang berbeda yaitu normal dry matter (NDM), high dry matter (HDM), dan low dry matter (LDM). Pengambilan sampel gas CH4 dilakukan menggunakan close chamber dan diukur pada rentang waktu pukul 10.00-11.00 WIB dengan interval waktu 15 menit sekali. Hasil penelitian menunjukkan bahwa nilai fluks CH4 pada setiap perlakuan tidak berbeda nyata (P, The dairy farming subsector produces dairy products but has the potential to exacerbate the environment issues, one of which is an increase in methane gas (CH4) emissions from livestock manure. Feeding management and the use of specific feed ingredients are key strategies for mitigating CH4 emission mitigation. The purpose of this study was to analyze CH4 gas flux from heifer manure influenced by different levels of dry matter feed. The study used a Latin square design model (3x3) with normal dry matter (NDM), high dry matter (HDM), and low dry matter (LDM) treatments. Gas CH4 sampling was carried out using a close chamber and measured between 10.00-11.00 at 15 minutes intervals. The results showed that the CH4 gas values for each treatment were not significantly different (p>0.05). The highest average daily of CH4 gas flux was obtained from HDM treatment at 377,53 mg/m2 , then NDM treatment at 271,81 mg/m2 , and LDM treatment at 195,53 mg/m2 . The CH4 flux values from heifer manure with different feed rations resulted in the samilar CH4 gas production
Keyword: gas metana, kotoran, rasio pakan, sapi perah dara

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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