Judul: Production and Characterization of Biochar from Torrefaction of Palm Oil Solid Waste
Abstrak: Limbah padat kelapa sawit yang semakin melimpah masih belum dimanfaatkan dengan baik dan dapat menyebabkan masalah lingkungan. Penelitian ini bertujuan memanfaatkan limbah padat kelapa sawit menjadi bioarang. Percobaan diawali dengan preparasi sampel, torefaksi, dan karakterisasi bioarang sesuai dengan parameter standar mutu bioarang berdasarkan SNI 01−6235−2000. Limbah padat kelapa sawit diantaranya cangkang, pelepah, dan tandan kosong kelapa sawit (TKKS) diolah kembali menjadi bioarang melalui proses torefaksi pada suhu 200–300 ℃. Parameter uji ialah kadar air, kadar abu, zat terbang, karbon terikat, daya serap iodin, dan kadar logam dengan spektroskopi serapan atom. Bioarang yang diperoleh dari cangkang, pelepah, dan TKKS terbukti memenuhi standar nasional Indonesia. Bioarang dari cangkang kelapa sawit memiliki kualitas terbaik dengan rendemen tertinggi 45,7%, kadar air dan abu yang rendah masing−masing 2,5% dan 1,9%, kadar zat terbang dan karbon terikat tertinggi masing−masing 12% dan 82%. Bioarang yang dihasilkan terbukti mengandung logam Cu, Mg, K, Ca yang bermanfaat sebagai bahan pembenah tanah., Palm oil solid waste which was increasing in number weren’t optimally utilized and can cause environmental problems. This study aims to use palm oil solid waste into biochar. The method, was carried out by sample preparation, torrefaction, and biochar characterization by the parameters of the biochar quality standard based on SNI 01−6235−2000. Palm oil solid waste, including shells, fronds, and empty fruit bunches (EFB), is reprocessed into biochar through a torrefaction process with a temperature of 200−300 ℃. The results showed data on several parameters, namely, water content, ash content, volatile matter, bound carbon, absorption of iodine, and metal content using Atomic Absorption Spectroscopy (AAS). Biochar obtained from the shell, fronds, and EFB is proven meets Indonesian national standards. Biochar from oil palm shells has the best quality with highest yield of 45,7%, low moisture and ash content of 2,5% and 1,9%, respectively, volatile matter, and highest bound carbon content of 12% and 82%. It's shown that metal content Cu, Mg, K, and Ca are good for soil enhancers.
Keyword: Bioarang, limbah padat kelapa sawit, pembenah tanah, torefaksi, Biochar, palm oil solid waste, soil repairer, torrefaction

Judul: Pyrolysis Process Design for Biochar Production from Empty Oil Palm Fruit Bunch
Abstrak: Perkembangan luas areal kelapa sawit di Indonesia setiap tahunnya cenderung meningkat. Sehingga terdapat banyak limbah biomassa Tandan Kosong Kelapa Sawit (TKKS) yang dihasilkan dari pabrik kelapa sawit. Salah satu teknologi yang dapat digunakan untuk mengatasi masalah tersebut yaitu teknologi pirolisis. Pirolisis adalah proses pembakaran tanpa oksigen untuk memproduksi biochar dengan produks samping adalah bio-oil dan gas. Tujuan dalam penelitian ini yaitu untuk mengetahui pengaruh suhu dan waktu untuk memproduksi biochar (arang), melakukan desain keteknikan dengan mendesain alat pirolisis pada PKS Cikasungka dengan kapasitas 25 Ton/Jam, serta menghitung total panas yang dibutuhkan untuk melakukan proses pirolisis dan membandingkannya dengan energi panas (Q) bahan bakar yang dihasilkan dari limbah kelapa sawit. Pada penelitian ini digunakan variabel suhu pirolisis yaitu 300
Keyword: pirolisis, tandan kosong kelapa sawit, biochar, energi panas

Judul: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
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