Judul: Karakteristik Briket Arang dari Tempurung Kelapa (Cocos nucifera.) dan Kayu Ulin (Eusideroxylon zwageri.).
Abstrak: Penelitian ini bertujuan untuk mengetahui karakteristik briket arang tempurung kelapa (Cocos nucifera) dan kayu ulin (Eusideroxylon zwageri) yang berupa sifat fisis dan mekanis. Briket arang dibuat dengan cara konvensional dengan penambahan perekat kanji dan molasses beserta komposisi arang tempurung kelapa (Cocos nucifera) dan kayu ulin (Eusideroxylon zwageri) yang berbeda setiap jenisnya, mulai dari komposisi 100% sampai 50%-50%. Hasil penelitian menunjukkan sifat fisis dan sifat mekanis briket arang sebagai berikut, kerapatan 0.71-1.07 g/cm³, keteguhan tekan 1.64-55.60 kgf/cm², kadar air 3.62% - 7.99%, kadar zat menguap 14.15-28.98%, kadar abu 0.53% -3.02%, nilai karbon terikat 63.05% -77.92%, dan nilai kalor 6141.77-7374.60cal/g.
Keyword: batok kelapa, kayu ulin, briket arang, tapioka, molasses

Judul: Karakteristik Briket Arang dari Tempurung Kelapa (Cocos nucifera) dengan Penambahan Bakau (Rhizophora spp) dan Laban (Vitex pubescens).
Abstrak: Pemanfaatan Energi Baru dan Terbarukan merupakan salah satu upaya peningkatan penyediaan dan pemanfaatan energi yang bermanfaat bagi semua pihak. Penelitian ini bertujuan mengetahui pengaruh komposisi bahan baku terhadap sifat fisis, mekanis dan kimia briket arang. Hasil penelitian menunjukkan sifat fisis, mekanis dan kimia briket yang dihasilkan yaitu kadar air rata-rata 5,21±1,68%, kadar zat terbang 15,97±4,10%, kadar abu 3,93±0,64%, nilai karbon terikat 74,51±4,51%, kerapatan 0,70±0,08 g/cm3, kuat tekan 31,23±13,83 kgf/cm2 dan nilai kalornya 6556±406 kal/g. Pengurangan arang tempurung kelapa pada campuran briket arang menyebabkan penurunan nilai kalor.
Keyword: bakau, briket arang, laban, tempurung kelapa

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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