Judul: Uji Performansi Alat Pengering Tipe Rak dan Pengaruh Perlakuan Awal terhadap Mutu Jahe Kering (Zingiber officinale Rosc.)
Abstrak: Ginger (Zingiber officinale Rosc.) is one of spices and medicinal plant which has high economic value and have been widely recognized by the Indonesian people. Fresh ginger has moisture content between 85-91% wet basis causes reduction quality of ginger if it is not eventually to be processed or dried. Generally, farmers and traders dried the ginger by using sun drying which require a lot of time, so that the artificial drying is needed to produce dried ginger with better quality and can shorten the drying time. The objectives of the research are to conduct the performance assessment of Sunbeam Food Dehydrator, which is rack-type dryer that using electrical energy as heat source; to assess the effect of immersion in lime solution (Ca(OH)2) at concentration of 2%, 4% and 6% to the quality of dried ginger; as well as studying the temperature distribution and air flow patterns in the dryer using Computational Fluid Dynamics (CFD). The results of the research showed that the dryer has capacity about 1kg of ginger slice and drying efficiency of 25.09%. It also shown that the immersion in lime solution gave a significant effect on increasing ash content and lightness of dried ginger, but it gave no significant effect on essential oil content of dried ginger. The treatment of immersion in 6% concentration of lime solution produce dry ginger with ash content that beyond of quality standard limit. The simulation of temperature and air flow patterns inside the dryer showed the accuracy of 97.09% and resulting linear regression of the relationship between measurement temperature and simulation temperature of 0.943. This shows that the CFD simulation gives good results in predicting the distribution of air temperature and air flow patterns inside the dryer.
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Judul: Uji Performansi Alat Pengering Efek Rumah Kaca (ERK) Hybrid Tipe Rak untuk Pengeringan Temulawak (Curcuma xanthorizza Roxb.)
Abstrak: Wild ginger (Curcuma xanthorizza Roxb.) is one of Indonesian native plants that can be used as herbal medicine to increase the appetite and to treat liver disorder and malaria. The objectives of this study are to test the dryer performance of the rack type hybrid green house effect dryer for drying of wild ginger and to analyze the temperature distribution in the drying chamber. The drying of 21.08 kgs slice wild ginger at 82.87 % wb to 10.46 % wb need 27.5 hours with temperature drying at 45.47 ⁰C, drying efficiency of 4.247 % and total specific energy consumption of 57.414 MJ/kgs vapor. The drying of 60.75 kgs slice wild ginger at 81.31 % wb to 8.55 % wb need 30.5 hours with temperature drying at 41.77 ⁰C, drying efficiency of 8.519 % and total specific energy consumption of 28.611 MJ/kgs vapor. The average of thermal efficiency of all experiments is 20.99 %, with variety of 5.37 %. The use of dryer for full capacity is more suggested for energy saving.
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Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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