Judul: Optimasi Mutu Briket Arang Campuran Cangkang Bintaro (Cerbera Odollam Gaertn) Dan Tempurung Kelapa Dengan Metode Respon Permukaan.
Abstrak: Briket arang merupakan salah satu alternatif bahan bakar yang memiliki potensial besar untuk dikembangkan. Ketersediaan cangkang bintaro dan tempurung kelapa di lingkungan sangatlah melimpah bahkan seringkali tidak termanfaatkan dengan baik. Tujuan penelitian ini untuk menentukan kondisi optimal pembuatan briket arang campuran cangkang bintaro dan tempurung kelapa, menganalisis pengaruh antar faktor, dan menentukan harga pokok produksi briket arang. Variabel faktor yang dianalisis yaitu konsentrasi arang cangkang bintaro dalam campuran (X1) 30, 40, dan 50% , suhu karbonisasi (X2) 350, 400, dan 450 0C , dan konsentrasi perekat tapioka (X3) 3, 4, dan 5%. Penelitian ini menggunakan Central Composite Design (CCD) dengan variabel respon yaitu kadar air, kadar zat menguap, kadar abu, dan nilai kalor. Pengujian tambahan yang dilakukan yaitu kerapatan, keteguhan tekan, dan kadar karbon terikat. Solusi optimum yang direkomendasikan oleh program Design Expert 7.0.0 untuk keempat respon tersebut adalah konsentrasi arang cangkang bintaro 37.6%, suhu karbonisasi 430 0C, dan konsentrasi perekat tapioka 3.4% dengan nilai desirability 0.924. Hasil yang diperoleh yaitu nilai kerapatan 0.55 g/cm3, keteguhan tekan 2.28 kg/cm2, kadar air 1.09%, kadar zat menguap 28.31%, kadar abu 5.87%, kadar karbon terikat 65.82%, dan nilai kalor 6835 kal/g. Harga pokok produksi briket arang adalah Rp 27 923 per kg.
Keyword: briket arang, cangkang bintaro, tempurung kelapa, metode respon permukaan

Judul: Analisis Briket Arang Berbahan Dasar Limbah Organik Padat Sebagai Bahan Bakar Alternatif
Abstrak: Penelitian ini bertujuan untuk mengetahui mutu briket arang berbahan dasar tempurung kelapa, serbuk gergaji kayu jati dan sekam padi berdasarkan standar SNI dengan parameter kadar air, kadar abu, kadar zat menguap dan kadar karbon serta variasi komposisi bahan baku terbaik terhadap mutu briket arang yang dihasilkan. Briket arang dibuat dengan cara konvensional dengan komposisi arang tempurung kelapa, serbuk gergaji kayu jati dan sekam padi yang berbeda serta penambahan perekat kanji. Hasil penelitian menunjukkan mutu briket arang sebagai berikut, kadar air 28,09 - 33,07 %, kadar abu 24,06 - 31,16 %, kadar zat menguap 2 – 18 % dan kadar karbon 53,45 – 70,41 %., This study aims to determine the quality of charcoal briquettes made from coconut shell, teak sawdust and rice husks based on SNI standards with parameters of water content, ash content, volatile matter content and carbon content as well as variations in the composition of the best raw materials on the quality of the produced charcoal briquettes. Charcoal briquettes are made in a conventional way with different compositions of coconut shell charcoal, teak sawdust and rice husks and the addition of starch adhesive. The results showed the quality of charcoal briquettes as follows, water content 28,09 – 33,07 %, ash content 24,06 – 31,16 %, volatile matter content 2 – 18 % and carbon content 53,45 - 70,41 %.
Keyword: coconut shell, teak sawdust, rice husk, charcoal briquettes

Judul: The Dynamic of HIV Virus Infection as a Result of Protease Inhibitor Therapy.
Abstrak: Acquired immunodeficiency syndrome (AIDS) is defined as symptoms of deterioration human immune system caused by human immunodeficiency virus (HIV). The virus damages the leucocytes; therefore, once a person infected by the HIV, his/her immune system will be paralyzed and eventually will not be able to survive from any disease. HIV is transmitted in many ways, such as having unsafe sex, using unsterilized syringe, blood transfusion, and many more. So far, there has not been discovered yet a way or a medicine that can totally cure this disease. However, reverse transcriptase inhibitor therapy, protease inhibitor, or combination of those two can decline the growth of virus inside the body of the infected person. Therefore, the immune system will be enhanced back to normal phase. In this paper, will analyze the effect of protease inhibitor therapy on the dynamics of virus inside the blood with different value of effectiveness. There are two mathematical models of protease inhibitor therapy to consider, i.e. perfect and imperfect protease inhibitor. The perfect protease inhibitor therapy hinders the virus to grow well and not to infect healthy leucocytes. On the other hand, the imperfect one cannot completely detained the virus growth.
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