Judul: Making Palm Briquettes and Thermal-Mechanical Testing as Coal Co-firing Energy Material
Abstrak: Penggunaan bahan bakar fosil semakin meningkat untuk memenuhi kebutuhan energi. Pemanfaatan biomassa menjadi briket dapat dikembangkan sebagai bahan bakar alternatif. Briket dibuat untuk teknik co-firing tandan kosong kelapa sawit dan batubara. Penelitian ini bertujuan memperoleh briket komposit dengan sifat termal-mekanik untuk menurunkan penggunaan batubara. Hasil penelitian menunjukkan bahwa briket komposit dapat menurunkan kadar abu dan karbon tetap, serta meningkatkan kadar zat terbang pada uji proksimat. Hasil uji ultimat menunjukan briket komposit dapat menurunkan emisi gas dengan menurunkan kandungan unsur N dan S. Hasil uji termal pada nilai kalor masih kurang dari briket batubara. Briket komposit dapat mempercepat waktu penyalaan dan laju pembakaran. Uji mekanik briket komposit memberikan hasil bahwa kerapatan dan kuat tekan masih lebih kecil dari briket batubara., The use of fossil fuels is increasing to meet energy needs. Utilization of biomass into briquettes can be developed as an alternative fuel. Briquettes are made for the co-firing technique of empty palm oil and coal bunches. This research aims to obtain composite briquettes with thermal-mechanical properties to reduce coal use. The research results show that composite briquettes can reduce ash and fixed carbon levels, as well as increase volatile matter levels in proximate tests. The ultimate test results show that composite briquettes can reduce gas emissions by reducing the content of N and S elements. The thermal test results show that the heating value is still less than that of coal briquettes. Composite briquettes can speed up ignition time and combustion rate. Mechanical tests of composite briquettes showed that the density and compressive strength were still smaller than coal briquettes.
Keyword: briket, batubara, co-firing, tandan kosong kelapa sawit

Judul: Pengaruh Jenis dan Kadar Bahan Perekat pada Pembuatan Briket blotong  sebagai bahan Bakar Alternatif
Abstrak: Briquette is one alternative fuel that is simple and has great potential to be developed. This study aims to determine the appropriate adhesive material in the manufacture of briquettes from filter cake, and to know the effect of adding tapioca adhesive or molasses adhesive in the making of filter cake briquettes. Preliminary studies conducted to find out that blotong can be utilized into briquettes. In the main study conducted by making briquettes using different adhesive materials, using adhesives molasses and tapioca adhesive with adhesive levels respectively 10%, 15%, and 20%. Preliminary research results indicate that filter cake waste into raw materials can be used briquettes. The results of descriptive analysis of this study was the addition of adhesive in the making of filter cake briquettes will cause the density becomes high, the firing rate becomes small and can increase the calorific value of briquettes from 1026 cal /gram to reach 1995 cal /gram. The resulting coal filter cake briquettes good enough, that is by generating a temperature coal between 357.22 to 496.11 ° C. In addition, this filter cake briquettes produce low ash content and levels of substances to fly higher than wood charcoal briquettes on the market. Briquette with the best quality based on the calculation method Composite Performance Index (CPI) is the briquettes with an adhesive mixture of 15% molasses. These briquettes have a calorific value and the highest temperature of the coals so much faster in boiling 300 ml of water, is for 17 minutes.
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Judul: Analisis kestabilan model penyebaran gonorrheae
Abstrak: Gonorrheae merupakan sejenis penyakit kelamin yang disebabkan oleh bakteri gonococcus yang menyebar melalui hubungan seksua!. Penderita 'penyakit ini umumnya para pekerja seks alau mereka yang melakukan seks tak wajar. Penyakit ini memiliki karakteristik unik yang mendasar yakni tidak ada kekebalan, artinya bahwa bila penderita yang dinyatakan sembuh kemungkinan untuk terjangkit sangat besar dan setiap individu yang rentan akan terinfeksi jika berhubungan seksual dengan penderila penyakit Inl. Martin Braun (1975) membuat suatu model epidemik tentang penyebaran penyakit gonorrheae. Pemodelan ini hanya membahas penyebaran gonorrheae yang disebabkan oleh hubungan seksual lawan jenis (heteroseksual).
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