Judul: Economic Benefits of Biogas Energy Use from Dairy Cow Dung (Case Study: Mundu Village, Tulung District, Klaten Regency)
Abstrak: Desa Mundu merupakan salah satu desa sentra peternakan sapi di Jawa Tengah. Aktivitas peternakan dengan jumlah ternak yang banyak menghasilkan limbah dalam jumlah besar sehingga berpotensi mencemari lingkungan. Eksternalitas negatif dari peternakan dapat diminimalisir dengan memanfaatkan limbah ternak menjadi biogas. Biogas sebagai energi terbarukan mampu mensubstitusi penggunaan bahan bakar fosil. Desa Mundu telah memiliki 67 unit digester biogas, namun ada beberapa unit yang sudah tidak aktif karena kurangnya perawatan dan pemahaman dari peternak. Berdasarkan hal tersebut tujuan dari penelitian ini yaitu; (1) menganalisis potensi energi biogas, (2) menganalisis manfaat ekonomi penggunaan limbah ternak menjadi biogas, (3) merumuskan strategi keberlanjutan pemanfaatan biogas di Desa Mundu. Metode yang digunakan adalah analisis potensi energi biogas, analisis konsumsi energi rumah tangga peternak, analisis SWOT dan QSPM. Hasil penelitian menunjukkan bahwa (1) potensi energi biogas mencapai 176,57 m3/hari dari keseluruhan peternak sapi. (2) Penggunaan energi biogas memberikan manfaat ekonomi berupa penghematan pengeluaran pembelian gas elpiji dengan rata-rata sebesar Rp56.535,00/bulan/KK. (3) Strategi keberlanjutan yang menjadi prioritas utama adalah mendorong pengoptimalan potensi kotoran ternak sapi menjadi biogas sebagai sumber energi alternatif yang ramah lingkungan dalam memenuhi kebutuhan energi masyarakat Desa Mundu., Mundu Village is one of the dairy farming centers in Central Java. Farming activities with a large number of livestock produce large amounts of waste that have potential to pollute the environment. Negative externalities can be minimized by utilizing livestock waste into biogas. Biogas as a renewable energy can substitute the use of fossil fuels. Mundu Village has 67 biogas installation units. Unfortunately, there are several units that are no longer active due to lack of maintenance and understanding from the farmers. The objectives of this study are to; (1) analyze the potential of biogas energy, (2) analyze the economic benefits of using livestock waste into biogas, (3) formulate a strategy for the sustainability of biogas utilization. The methods used in this research are analysis of biogas energy potential, analysis of farmer household energy expenditure, SWOT and QSPM analysis. The results showed that (1) biogas energy potential reached 176,57 m3/day. (2) The use of biogas energy provides economic benefits, with an average savings value is Rp56.535,00/month/household. (3) The priority sustainability strategies is to encourage the optimization of the potential of cow dung into biogas as an alternative energy source to meet the energy needs of the Mundu Village community.
Keyword: biogas energy potential, renewable energy, sustainability strategy, 

Judul: Feasibility of Sheep and Biogas Farming (Case Study: Cikarawang Farm)
Abstrak: Jawa Barat merupakan provinsi dengan jumlah peternakan domba terbesar di Indonesia, yaitu 9.987.870 ekor domba pada tahun 2022. Hal tersebut menimbulkan permasalahan lingkungan salah satunya adalah limbah feses atau kotoran domba yang belum dimanfaatkan. Penelitian ini berfokus pada kelayakan usaha peternakan domba dan penerapan biogas di Cikarawang Farm, Bogor. Penelitian ini bertujuan untuk menganalisis kelayakan finansial dan non-finansial dari penggunaan teknologi biogas dalam peternakan domba, serta melakukan analisis switching value. Data dikumpulkan dari 32 responden menggunakan kuesioner dan wawancara. Data dianalisis dengan kriteria investasi seperti NPV, IRR, Net B/C dan PP. Tanpa biogas, NPV sebesar Rp466.418.189, IRR mencapai 22%, Net B/ sebesar 1.04 dan PP selama 4.5 tahun. Sementara itu, dengan penerapan biogas, Rp578.762.730 , IRR naik menjadi 28%, Net B/C juga meningkat menjadi 1.34 dan Payback Period berkurang menjadi 4.1 tahun. Analisis switching value mengindikasikan bahwa penurunan harga domba dapat berdampak negatif pada pendapatan. Kesimpulannya, penggunaan teknologi biogas layak secara finansial dan non-finansial, meskipun terdapat tantangan yang perlu diatasi untuk memaksimalkan keuntungan dan keberlanjutan usaha., West Java is the province with the largest number of sheep farms in Indonesia, totaling 9,987,870 sheep in 2022. This creates environmental issues, particularly with untreated sheep manure. This study focuses on the feasibility of sheep farming and biogas application at Cikarawang Farm, Bogor, aiming to analyze the financial and non-financial aspects of biogas technology, as well as conduct a switching value analysis. Data were collected from 32 respondents through questionnaires and interviews, and analyzed using investment criteria such as NPV, IRR, Net B/C, and Payback Period (PP). Without biogas, NPV was Rp466.418.189, IRR was 22%, Net B/C was 1.04, and PP was 4.5 years. With biogas, NPV rose to Rp578.762.730, IRR increased to 28%, Net B/C rose to 1.34, and Payback Period extended to 4.1 years. The switching value analysis indicates that a decrease in sheep price can negatively impact income. In conclusion, biogas technology is financially and non-financially feasible, though challenges remain to maximize profits and business sustainability.
Keyword: biogas, domba, non finansial, Switching Value, aspek finansial

Judul: Characterizations of low alloy steel sae 4422  plated with chromic acid (Cro3)
Abstrak: Characterizations of low alloy steel SAE 4422 plated with chromic acid (CrOrO3) was use Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), RD),Energy Dispersive Analysis of X-Ray (EDAX), Hardness Test and Roughness Test. Microstructures analysis exhibits cracks and grain boundaries microcracks as a characteristics of chrome metal found at plating metal. Perlite and Ferrite as grains of steel found at base metal with grain boundaries around it. Phase analysis of plating metal appropriate to chrome metal with lattice constant (a) is 2.559 Å and phase analysis of base metal appropriate to iron ferrite with lattice constant (a) is 3.318 Å. Both plating and base metal have cubic system. Chemical analysis of plating metal at surface section exhibits that cracks area have highest value of carbon element compare with grains and grains boundaries area. While chemical analysis of base metal at cross section exhibits that perlite have highest value of carbon element compare with ferrite and grain boundaries. The hardness value of plating metal at surface section and cross section are 753 and 637 VHN. While, the hardness value of base metal and interface area at cross section are 205 and 373 VHN. The roughness value at measurement points of chrome surface for as received sample are 0.445 μm. Observation used Optical Microscopy and Scanning Electron Microscopy exhibits surface irregularities combine to form surface texture of plating metal at surface section.
Keyword: