Jurnal Keteknikan Pertanian
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Pengembangan Tungku Gasifikasi Arang Biomassa Tipe Natural Draft Gasification Berdasarkan Analisis Computational Fluid Dynamics (CFD)
Get PDFAbstractA biomass stove based on natural draft gasification (NDG) has been developed in a previous study (Nelwa, et al. 2013) by using simulation based on heat transfer and equilibrium modeling. In this study, a CFD simulation was performed in order to analyze the effect of chimney height, and inlet hole diameter of the stove to the performance of the stove. The results of simulation showed that power produced by stove was between 1863.9 J/s until 2585.7 J/s, and its gasification efficiency was 67.11%. The results of simulation also showed that charcoal gasification produces combustible gases (CO, CH4, and H2) at the bottom and the center of stove, and then they were oxidized by secondary air at the top of stove. This oxidation reaction produces sufficient heat energy which can be used for cooking process.Keywords: stove, power, combustible gas, gasification efficiencyAbstrakSebuah Disain tungku natural draft gasification (NDG) telah diciptakan sebelumnya (Nelwa, et al. 2013) dengan menggunakan pemodelan dan simulasi berbasis pindah panas, dan equilibrium. Penelitian ini menggunakan simulasi computational fluid dynamics (CFD) untuk menganalisis performa tungku pada bagian geometri cerobong gas bakar, dan lubang udara sekunder. Hasil simulasi dari beberapa skenario tungku yang dilakukan dapat disimpulkan bahwa dari skenario disain tungku didapatkan daya tungku antara 1863.9 J/detik sampai dengan 2585.7 J/detik, dan memiliki efisiensi gasifikasi sebesar 67.11%. Proses gasifikasi arang kayu menghasilkan gas mampu bakar CO, CH4, dan H2, dimana gas mampu bakar tersebut mengalami reaksi pembakaran dengan aliran udara sekunder yang masuk di bagian tengah saluran gas mampu bakar. Reaksi pembakaran ini, menghasilkan energi panas yang memadai untuk proses memasak.Kata Kunci: tungku, daya, gas bakar, efisiensi gasifikasiDiterima: 02 Mei 2014; Disetujui: 15 Agustus 201
Pelapis Nanokomposit untuk Pengawetan Salak Pondoh Terolah Minimal
Get PDFAbstractMinimally-processed snake fruit is a perishable product with a very short shelf life. Edible coating is one of the alternative technologies to prolong the shelf life of minimally-processed fruit. The research aimed to examine antimicrobial activity of edible coating nanocomposites-based pectin and starch with NP-ZnO suspensions and the influence of edible coating on quality of minimally-processed snake fruit during storage. Quality parameters measured were on the weight loss, browning index, the hardness, and sensory evaluation. The result showed that antimicrobial activity of edible coating nanocomposites againts Escherichia coli and Staphylococcus aureus. The application of nanocomposites are able to maintain the quality of minimally-processed snake fruit during the storage periods. Minimally-processed snake fruit with edible coating made from nanocomposites-based pectin and starch with NP-ZnO can extend its shelf life and maintained its quality until 14 days, while minimally-processed snake fruit without edible coating can extend only 8 daysKeywords: minimally-processed, nanocomposites, NP-ZnO, snake fruitAbstrakBuah salak pondoh terolah minimal merupakan buah dengan umur simpan yang pendek. Salah satu alternatif yang dapat diterapkan untuk memperpanjang umur simpan buah terolah minimal adalah dengan penggunaan edible coating. Penelitian ini bertujuan untuk mengkaji aktivitas antimikroba pelapis nanokomposit berbasis pektin dan pati dengan NP-ZnO dan pengaruhnya terhadap mutu salak pondoh terolah minimal selama penyimpanan. Parameter mutu yang dianalisis adalah susut bobot, browning index, kekerasan, dan uji organoleptik. Hasil penelitian menunjukkan bahwa pelapis nanokomposit memiliki aktivitas antimikroba terhadap Escherichia coli dan Staphylococcus aureus. Aplikasi pelapis nanokomposit dapat mempertahankan mutu salak pondoh terolah minimal selama penyimpanan. Salak pondoh terolah minimal dengan pelapis nanokomposit berbasis pektin dan pati dengan NP-ZnO dapat memperpanjang umur simpan dan mempertahankan kualitas hingga hari ke-14, sedangkan salak pondoh terolah minimal tanpa pelapis hanya dapat bertahan hingga hari ke-8.Kata kunci : nanokomposit, NP-ZnO, salak pondoh, terolah minimalDiterima: 19 Desember 2014; Disetujui: 25 Maret 201
ANALlSIS SUDUT DATANG RADIASI MATAHARI UNTUK PENGEMBANGAN MODEL PINDAH PANAS PADA RUMAH KACA DI DAERAH TROPIKA
No full textABSTRACT A heat transfer model has been developed for a naturally ventilated greenhouse under the tropical climatic conditions. In the tropical region, greenhouses are characterized by high exposure in solar radiation and air exchange through natural ventilation. Therefore in this research, incident angle of solar radiation on the greenhouse roof surface has been considered as an important factor to improve the accuracy in calculating the radiation received by the greenhouse. The heat transfer model consists of four layers represent the cover, inside air, floor surface and soil layers of the greenhouse. The model was applied to a naturally ventilated standard-peak greenhouse. A computer program was developed to predict the temperature of the inside air. Incident angle of direct solar radiation on roof surface and outside microclimate parameters data were used as the input values. Heat transfer equations were solved by using the Runge-Kutta Method while the angle of direct solar radiation with the roof surface was calculated by using the principles of geometry. Results show that the model performed well in predicting the temperature of the inside air as compared to that of the measure value.Diterima: 4 Januari 2007; Disetujui: 26 Pebruari 200
KAJIAN KEBIJAKAN ALAT DAN MESIN PERTANIAN
No full textABSTRACT The development of agricultural mechanization In Indonesia is still very low, even though it is believed that a proper application of agricultural mechinery can improve agricultural productivity and netional competitiveness significantiy. The development of agro-machinery industry is also very low due to unfavorable policy. This paper disclose the trend of agricultural mechanization development in Indonesia and the policy that may influence the trend. The paper concluded that (1) procurement system of agro-machinery should take Into account its appropriateness to the local requirement and condition, (2) lnter-sectoral regulation should consider the possibility to enhance local and domestic agro-mechinery industry. and (3) the local government should establish an mtersectoral technical unit In charge of agricultural mechanization. Keywords: agricultural mechanization, agro-mechinery industr, deregulation Diterima: 20 Agustus 2007, Disetujui: 20 Nopomber 2007
PERKEMBANGAN PROSES PEMBUATAN BIODIESEL SEBAGAI BAHAN BAKAR NABATI (BBN)
No full textABSTRACT As energy dernands increase and fossil fuel reservas are limited, research is directed towards alternative renewable fluls. A potential diesel fuel substitusi is biodiesel, obtained from fatty acids methyl esters (FAME) and produced by the transesterfication reaction of triglyceride or free fatty acid (FFA) of vegetable oils with short-chain alcohol, mainly methanol. Most of the currently of alcohol. Although the removal of the excess alcohol can be easily achieved by distillation, however the removal of catlyst and the by-product formed from its reaction with the reactants is complicated while several methode for glycerol purification have been reported. The disadvantages resulting from the use of a catalyst and itsremoval from theproducts can beeliminated if a non-catalytic reaction of the vegetable oils with alcohol can be realized and a simpler and cheaper process can be developed.indonesia has the opportunity to expand oil palm and other plantations such as jatropha curcas (jarak pagar)in order to provide sufficient amount of crude oil for development of biodiesel industry. Keyword: biodiesel, vegetable oil, renewable source of energy, catalyst, non-catalytic, transesterfication Diterima: 6 April 2006; Disetujui: 19 Juli 200
Faktor Influencing the Vacuum Freezing Rate of Liquid Food
No full textMany,freezing methods, mechanicul as well as cryogenic, have been in wide application in food industries. Each method has its own advantage, but in regard with the food quality, freezing rule can be accomplished by the method is one of the tnost important factors. Nowadays, many researchers are conducting experiment in order to enhance thefi.eezing rate. This paper deals with the advantage of vacuum freezing method in enhancing the freezing rate and its applicability for liquidfood.Experinrent was carried out for distilled water, milk, and fruit juice using multi-purpose vacuum equipment. As easily predicted, minimum pressure of the freezing chamber determine temperature of the product. Vuriation on the fruit juice concentration shows that faster freezing rate canbe achieved if the product is more dilute. The experiment also showed that freezing rute obtained by vacuumj-eeziirg was signijkantly faster than contact plate freezing method
Kinetic Model of Biodiesel Processing Using Ultrasound
No full textUltrasound is predicted to be able to accelerate the chemical reaction, to increase the conversion of plant oil into biodiesel, and to decrease the need of catalyst and energy input. The application of ultrasound for processing of biodiesel and the mathematical model were conducted in this research. The result of the experiments showed that the ultrasound increased reaction rate and the conversion of palm oil into biodiesel up to 100%. It was better than the process with mechanical stirrer that the conversion was just 96%. The duration to complete the process using ultrasound was 1 minute. It was 30 to 120 times faster than that withmechanical stirrer. Ultrasound transforms mechanical energy into inner energy of the fluids and causes an increasing of temperature. Simultaneously, natural mixing process undergo because of acoustic circulation. Simulation with experiment data showed that the acceleration of transesterification with ultrasound was affected not only by natural mixing and increasing temperature. The cavitation, surface tension of micro bubble, and hot spot accelerate chemical reaction. In fact, transesterification of palm oil with ultrasound still needs catalyst. It needs only about 20% of catalyst compared to the process with mechanical stirrer.Keywords : Biodiesel, transesterification, mathematical modeling, ultrasoundDiterima: 16 September 2008; Disetujui: 10 Pebruari 200
Development of Powered Disk Type Sugar Cane Stubble Saver
No full textThe objective of this research was to design, fabricate and test a prototype of sugar cane stubble saver based on powered disk mechanism. In this research, a heavy duty disk plow or disk harrow was used as a rotating knife to cut the sugarcane stubble. The parabolic disk was chosen because it is proven reliable as soil working tools and it is available in the market as spare part of disk plow or disk harrow unit. The prototype was mounted on the four wheel tractor’s three point hitch, and powered by PTO of the tractor. Two kinds of disks were used in these experiments, those were disk with regular edge or plain disk and disk with scalloped edge or scalloped disk. Both disks had diameter of 28 inch. Results of field test showed that powered disk mechanism could satisfy cut sugar cane’s stubble. However, scalloped disk type gave smoother stubble cuts compared to that of plain disk. Plain disk type gave broken stubble cut. Higher rotation (1000 rpm) resulted better cuts as compared to lower rotation (500 rpm) both either on plain disk and scalloped disk. The developed prototype could work below the soil surface at depth of 5 to 10 cm. With tilt angle setting 20O and disk angle 45O the width of cut was about 25 cm.Keywords: sugar cane, stubble shaver, powered diskDiterima: 4 Nopember 2008; Disetujui: 11 Maret 200
Pengembangan Program Komputer untuk Pemilihan Kincir Angin Pembangkit Tenaga Listrik di Pedsaan
No full textAbstract Rural areas which have not getting electricity networks provided by Perusahaan Listrik Negara or PLN can consider constructing windmills to generate electricity. In the construction of these windmills, a special attention should be paid to such factors as topography of the location and wind speed in the site of windmills so that a proper type of windmills that will be used in the area can be decided. Therefore, developing a computer program for selecting the type of windmills used is expected to serve as an input for the development of agricultural technologies that utilize renewable energy. Making the computer program consists of the following steps: making the initial view layout of the program, program scripts, animation, and program evaluation. Making a program design is started by determining the input and output components of the program so as to set the initial view of the program. Based on the formulas used for windmills generating electricity, a computer program to determine the type of windmills was developed by using Visual Basic 6.0. Meanwhile, Adobe Flash CS3 Professional software was used to construct animated windmills, which can also be run under Visual Basic 6.0 program.Keywords: windmill, energy, electricity, power Diterima: 13 Maret 2010; Disetujui: 17 September 201
Pengembangan Alogaritma Pengolahan Citra untuk Menghindari Rintangan pada Traktor Tanpa Awak
Get PDFAbstractUnmanned tractors, even though it uses global positioning system (GPS) technology to identify the working path, still require an ability to recognize the environment in front of it in order to avoid obstacles thatmay exist. A device that can be used to recognize the environment in front of the tractor and avoid obstacles that may exist, is the camera. However, images captured by the camera need to be processed to detect possible obstacles at the front of the tractor. This study aimed to develop image processing algorithms to detect the possible presence of obstacles on the path to be traversed by an unmanned tractor, and directed the tractor to a safe path by giving the new coordinates when there are obstacles in front of it. Several mage processing techniques such as edge detection, opening and closing, marking free area, and the determination of the coordinates were used for the purpose of directing the path in front of the tractor when there are obstacles that must be avoided.Keywords: image processing, obstacles, unmanned tractor, algorithmsDiterima: 19 April 2010; Disetujui: 18 Oktober 201