Judul: Drying analysis of paddy based on cylindrinal-model
Abstrak: Little in-depth basic research has been conducted in INdonesia on drying mechanism and its charateristics. Knowladge on the drying characteristics is useful to design an eficient dryer, where air flow, temperature, humadity and the grain quantity to be dried cab be regulated, and that can be operated using variuos energy soutcess such as kerosene solar and biamass.
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Judul: Performance of Rotary Bed Dryer for Paddy in Several Configured Rotations
Abstrak: Mesin pengeringan tipe rotari tumpukan merupakan jenis pengeringan tipe mekanis untuk biji-bijian yang menggunakan prinsip putaran saat mengaduk bahan. Jenis biji-bijian yang digunakan pada penelitian ini adalah gabah. Penelitian ini bertujuan utuk mengetahui pengaruh perlakuan jeda dan lama waktu pengadukan dengan suhu tetap 45°C dalam meningkatkan keseragaman kadar air gabah menggunakan pengering tipe rotari tumpukan. Metode pengujian beda kadar air pada titik A dan B adalah pengukuran kadar air dengan prinsip gravimetri (oven) dan pengukuran keseragaman dengan prinsip t-test dengan P(t>T) dan faktor kesalahan α=0,05 pada dua sisi (two-tail). Hasil pengujian mesin pengering tipe rotari tumpukan menunjukkan bahwa seluruh perlakuan memberikan kadar air yang tidak berbeda (beda 0 %bb.) antar lapisan dalam dan luar pada akhir pengeringan. Konsumsi energi spesifik yang dibutuhkan sebesar 2684,7-4144,8 kJ/kg uap air sehingga menunjukkan bahwa konsumsi energi spesifik pengering tipe rotari tumpukan pada pengeringan gabah lebih kecil dibandingkan KES pengeringan biji-bijian konvensional (4260 kJ/kg uap air). Energi pengadukan hanya 2 % sedangkan energi pemanasan sebesar 89 % dari konsumsi energi total pengeringan dan biaya kebutuhan listrik. Hasil pengujian yang telah dilakukan menunjukkan adanya pengaruh besar proses pengadukan bahan yang dikeringkan untuk memperkecil nilai beda kadar air di lapisan luar dan lapisan dalam. Proses pengadukan tidak berpengaruh besar terhadap konsumsi energi spesifik dan biaya kebutuhan listrik., Rotary bed dryer is mechanical dryer for grains with rotary system for mixing grains. The grains that used in this study is paddy. The aim of this study is determine the impact of interval and duration of rotations with a fixed temperature in 45°C to increase the uniformity of the paddy with rotary bed dryer. Different moisture content test method for A and B point with gravimetric method (oven) and define uniformity using is used t-test statistic method in P(t>T) and failure factor (α) is 0,05 with two-tails test. The result of this rotary bed dryer show that all treatment was uniform (difference 0 %bb.) between inner and outer layer at the end of the drying process. The specific energy consumption required is 2684,7-4144,8 kJ/kg, it shows that the specific energy consumption of rotary bed dryer to reduce moisture content is smaller than the specific energy consumption of conventional grain drying (4260 kJ/kg). The mechanical energy was 2 % and the heated energy was 89 % of the total energy consumption and the cost of electricity. The results of the tests showed that the stirring process has to influence to decrease the different moisture content in outer later and inner layer. The stirring process does not effect the total energy consumption and the cost of electricity.
Keyword: drying, paddy, rotary bed dryer, uniformity

Judul: Hydroxyapatite-Chitosan Composite Coating on Stainless Steel 316 to Improve Corrosion Resistance
Abstrak: Metals that were used in bone implantation should have good corrosion resistance that were not easily corroded when implanted into the body. Metal corrosion resistance of stainless steel 316 can be enhanced through the metal coating by hydroxyapatite-chitosan composite with composition ratio of hydroxyapatite (gram) and chitosan 3% (mL) 0.2:0, 0.2:0.1, 0.2:0.5, 0.2:1.0, and 0.2:1.5. Besides improving the corrosion resistance of metal, the presence of chitosan also maintain the position of hydroxyapatite on metal surfaces. Corrosion resistance increases with increasing amount of chitosan added and the best composition of hydroxyapatite-chitosan composite was 0.2:1.0.
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