Judul: Rancang bangun dan Uji Kinerja Pengering  Singkong Efek Rumah Kaca (ERK)-Hibrid Tipe Rak dengan Turbin Ventilator untuk Sirkulasi Udara
Abstrak: Cassava is the fourth leading commodity after rice, wheat and corn. Market demand and high productivity of cassava make it as one of the potential export commodities. In case for export or industrial use fresh cassava must be processed first into semi-finished materials for added value. It will be better if the added value is left to the farmer. For the purpose, the farmer needs to be furnished with proper and affordable technology. This study aims to design, construct and testing a dryer which apply the principle of greenhouse effect by additional heating of biomass furnace. Dryer is designed with a capacity of 180 kilograms cassava from 65% wb moisture content up to 13% wb moisture content. Drying chamber has dimensions of 2 m x 1.5 m x 2.4 m (L x W x H) with 30 shelves. This dryer has a cross flow type heat exchanger and regulating the circulation of air using a turbine ventilator. On testing with the full capacity, the dryer can dried up 180 kg cassava chips from 61.31 %wb (158.53 %db) moisture content to 9.87 %wb (11.01 %db) moisture content. On these test the dryer has a total efficiency of 18.3%, energy share of solar energy 7.72% and biomass 92.28%, drying time is 49 hours at a rate of 4.50 %db/h. While testing with half capacity, was dried 95 kg cassava chips from moisture content of 69.47%wb (232.26 %db) to 8.81 %wb (9.67 %db), the total efficiency of the dryer was 14.84% with the share of energy from solar energy 7.31% and 92.69% of the biomass, drying time required is 28 hours with the drying rate 8.56 %db/h.
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Judul: Design and Performance Test of PV/T for Cassava Drying
Abstrak: Singkong merupakan salah satu pangan pokok di Indonesia. Singkong dapat diolah menjadi tepung singkong. Tepung singkong dibuat dengan mengeringkan singkong menjadi gaplek. Proses pengeringan gaplek umumnya dilakukan dengan penjemuran di atap atau tanah lapang Hal ini dapat mengakibatkan penurunan kualitas singkong karena kontaminasi bakteri dan jamur seperti aspergillus sp. Selain itu cuaca yang tidak menentu juga dapat memperlambat proses pengeringan. Pengeringan dengan alat pengering dapat menjadi solusi permasalahan tersebut. Desain pengering yang tepat diperlukan untuk mencapai target pengeringan yaitu kadar air singkong sebesar 14% b.b dan durasi pengeringan yaitu 5 hari atau kurang. Penelitian ini bertujuan untuk membuat sistem pengering singkong yang dapat menghasilkan energi secara mandiri dan bersih. Penelitian dimulai dengan merancang pengering singkong berkapasitas 4 kg dan bahan dengan potongan berbentuk chips setebal 3-4 cm. Ruang pengering didesain agar sampel dapat dialirkan udara secara maksimal. Rancangan sistem PV/T menggunakan panel surya 100 Wp seluas 0.67 x 0.76 m dengan kolom penukar panas yang terbuat dari kayu berlapis insulator. Fabrikasi pengering dilakukan setelah proses desain selesai. Pengujian pengering dilakukan 3 kali. Pengering singkong yang telah dibuat dapat mengeringkan singkong hingga mencapai kadar air rata-rata sebesar 30.77% b.b selama 5 hari dengan kelembaban udara absolut rata-rata pada cerobong sebesar 23.25 g uap air/kg udara kering dan suhu pengering rata-rata sebesar 37.76 °C., Cassava is one of the staple foods in Indonesia. Cassava can be processed into cassava flour. Cassava flour is made by drying cassava to produce cassava chips. The drying process for cassava chips is commonly done by sun drying on rooftops or open ground. However, this can result in a decrease in cassava quality due to bacterial and fungal contamination, such as Aspergillus sp. Additionally, unpredictable weather conditions can also slow down the drying process. Using a drying apparatus can be a solution to these problems. The appropriate drying design is needed to achieve the drying target, which is a moisture content of 14% (wet basis) and a drying duration of 5 days or less. This study aims to create a cassava drying system that can generate independent and clean energy. The research begins with designing a 4 kg capacity cassava dryer with sample chips thickness of 3-4 cm. The drying chamber is designed to allow for maximum airflow through the sample. The PV/T system design utilizes a 100 Wp solar panel with dimensions of 0.67 x 0.76 m and a heat exchanger column made of insulated wood. Fabrication of the dryer is carried out after the design process is completed. The dryer is tested three times. The constructed cassava dryer is capable of drying cassava to an average moisture content of 30.77% (wet basis) over 5 days, with an average chimney absolute humidity of 23.25 g of moisture/kilogram of dry air and an average drying temperature of 37.76 °C.
Keyword: Energy, Cassava, Drying, Performance, PV/T system

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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