Bambang Purwantana
Jurusan Teknik Pertanian Fakultas Teknologi Pertanian Universitas Gadjah Mada Jl. Flora, Bulaksumur, Yogyakarta 55281 Telp/Fax 0274-589797

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GASIFIKASI TANDAN KOSONG KELAPA SAWIT MENGGUNAKAN UPDRAFT GASIFIER Purwantana, Bambang; Prastowo, Bambang; Abineno, Jemseng Carles
Jurnal Teknotan Vol 7, No 1 (2013)
Publisher : Jurnal Teknotan

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Abstract

Limbah tandan kosong kelapa sawit sebanyak 6 juta ton/tahun dengan kandungan energi dalam bentuk gas sebesar 17.08 MJ/kg tandan perlu dimanfaatkan. Namun belum terungkap sejauh mana energi tersebut dapat dipanen secara efektif dengan alat gasifikasi yang ada. Penelitian ini dilakukan untuk mengetahui kinerja gasifikasi tandan kosong kelapa sawit menggunakan updraft gasifier. Metode deskriptif analisis dilakukan pada beberapa variasi ukuran potongan bahan, pemadatan umpan, dan laju aliran udara input, dimana kinerja gasifikasi ditentukan berdasarkan parameter laju gasifikasi, efisiensi, suhu proses, suhu nyala api pembakaran syngas, dan prosentase residu yang dihasilkan. Hasil penelitian menunjukkan bahwa gasifier tipe updraft cukup efektif untuk proses gasifikasi tandan kosong kelapa sawit dengan efisiensi proses 60–80 %, laju proses 2,75 – 3,50 kg/jam, dan menghasilkan syngas dengan suhu bakar 320 - 570 ºC. Kinerja gasifikasi terbaik dicapai pada debit udara input 300 - 400 lpm, ukuran potongan bahan < 4 cm, dan tekanan pada bahan 0,05-0,06 kg/cm2. Pada perlakuan tersebut dicapai laju proses sebesar 3-3,5 kg/jam, efektivitas proses 14 menit/kg, efisiensi proses 80 %, suhu nyala api syngas 540 °C. Kata kunci: gasifikasi, TKKS, ukuran, tekanan, kinerja
AUDIT ENERGI PADA BERBAGAI JENIS INDUSTRI TAHU BERDASARKAN TEKNOLOGI PEMASAKANNYA Markumningsih, Sri; Purwantana, Bambang; Sutiarso, Lilik
Jurnal Teknotan Vol 7, No 1 (2013)
Publisher : Jurnal Teknotan

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Abstract

Berdasarkan teknologi pemasakannya cara penggunaan energi selama ini pada beberapa jenis industri tahu disinyalir belum efisien. Penelitian dilakukan pada 4 produsen tahu yang masing-masing menggunakan teknologi pemasakan berbeda, yaitu; tungku tunggal, tungku ganda, ketel uap horizontal, dan ketel uap vertikal. Metoda deskriptif analisis digunakan untuk mengkaji rasio masukan-luaran energi. Energi masukan adalah tenaga kerja manusia, energi bahan bakar, energi yang sudah terbentuk, dan energi bahan, sedang energi luaran adalah energi tahu, dan energi ampas tahu. Hasil penelitian menunjukkan bahwa total input energi tertinggi sebesar 19.005,05 kJ/kg tahu terjadi pada ketel uap vertikal dan terrendah sebesar 6.026,80 kJ/ kg tahu pada tungku tunggal. Tingginya konsumsi energi untuk mengoperasikan ketel uap vertikal terjadi karena ia bekerja di bawah kapasitas normal. Kata kunci : audit energi, industri tahu, ketel uap, tungku
Penerapan Analisis Dimensi dalam Rancang Bangun Mesin Pembelah Biji Kedelai (Glycine max L.) Sistem Gesek Putar Rofarsyam, Rofarsyam; Purwantana, Bambang; Bintoro, Nursigit
Agritech Vol 32, No 2 (2012)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/agritech.9626

Abstract

The aim of this research was to design a spin friction type of soybean slicing machine needed in the preparation of tempeh raw material. Dimensional analysis method was used to develop a mathematical relationship between the slicing capacity and its design variables. The prototype was tested using 260 mm diameter of hoppers equiped by number of blades with staggering variations of 51, 102, and 240 mm; a 300 mm diameter of hopper equiped by hopper’s blades with staggering of 118 mm; a 90 mm diamater of rotor with blades spacing of 71 mm; a 180 mm diameter of rotor with blades spacing of 141 mm; and a 75 mm diameter of rotor equiped by blades with spacing of 59 mm. The results showed that the slicing capacity (Q), were infl uenced by mass of soybean (WB), angular velocity (n), mass of water (WA), processing time (t), soybean density (ñ), spacing of rotor blades (SR), length of rotor blades (HR), spacing of hopper blades (SH), length of hopper blades (HH), and hopper diameter (DH). The relation was mathematically expressed by: The slicing capacity (Q/WB.n) were infl unced 620 % by parameters of (DH/SR) and 2 % by (WA/WB). The mathematical equation could be recommended as a reference for determining the geometry and the operational development of soybean slicing machine.ABSTRAKPenelitian ini bertujuan untuk merancangbangun mesin pembelah biji kedelai sistem gesek putar yang diperlukan dalam penyiapan bahan baku pembuatan tempe. Pendekatan analisis dimensi digunakan untuk mendapatkan persamaan matematis yang menghubungkan kapasitas kerja pembelahan dengan parameter-parameter yang berpengaruh. Hasil rancangbangun diuji melalui variasi hopper berdiameter 260 mm dengan jarak sudu masing-masing 51, 102, dan 204 mm; hopper berdiameter 300 mm dengan jarak sudu 118 mm; rotor berdiameter 90 mm dengan jarak sudu 71 mm, rotor berdiameter 180 mm dengan jarak sudu 141 mm dan rotor berdiameter 75 mm dengan jarak sudu 59 mm. Dari hasil pengujian hubungan antara kapasitas pembelahan (Q) terhadap berat kedelai (WB), kecepatan putar (n), berat air (WA), waktu proses (t), massa jenis kedelai (ñ), jarak sudu rotor (SR), panjang sudu rotor (HR), jarak sudu hoper (SH), panjang sudu hoper (HH), dan diameter hoper (DH) adalah sebagai berikut:Pengaruh parameter rancangbangun terhadap kapasitas kerja pembelahan (Q/WB.n) yang paling besar adalah (DH/SR) yaitu sebesar 620 %, yang paling kecil adalah (WA/WB) sebesar 2 %. Model matematis tersebut dapat direkomendasikan sebagai acuan dalam penentuan dimensi dan operasional pengembangan mesin pembelah biji kedelai sesuai kapasitas kerja yang dikehendaki.
Studi Pola Pertumbuhan Tanaman Sawi (Brassica rapa var. parachinensis L.) Hidroponik di dalam Greenhouse Terkontrol Telaumbanua, Mareli; Purwantana, Bambang; Sutiarso, Lilik; Falah, Mohammad Affan Fajar
Agritech Vol 36, No 1 (2016)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/agritech.10690

Abstract

The vegetables should be cultivated in an optimal way to obtain maximum yield. In tropical regions such in Indonesia, the growth of vegetables are influenced by climate factors such as humidity, temperature, nutrients and light. To gain the optimal and controlled condition during the growth periode, mustard plants could be cultivated hydroponically in a greenhouse. This study was conducted to identify the growth pattern of mustard (Brassica rappa var. Parachinensis L.) that hydroponically planted in a greenhouse which is equipped with a temperature, nutrients and light control. The aim of this research is to determine the best factors combination that provide the most optimum growth. This research was conducted by three treatments that were temperature, nutrition, and light. Each of the treatment has three variations : temperature (32 °C, 35 °C, and 38 °C), nutrition (2 mS/cm, 5 mS/cm, and 8 mS/cm), and light (7000 lux, 12000 lux, and 17000 lux) so there were 27 cultivation spaces or greenhouses used with different micro-climates. The growth rate was determined by the area of the leaf and it was measured during 48 days of cultivation. Control in each greenhouse is done by a pump actuator, incandescent bulbs and TL lamps. The result showed that temperature, nutrients and light affect on the growth of mustard. By single factor analysis, we found that maximum leaf area was produced at a temperature of 35 °C that was 565 cm-, nutrition 5 mS/cm that was 639.27 cm- and 17000 lux light that was 697.42 cm-. In short, the best growth rate was obtained at a temperature of 35 °C, nutrition of 5 mS/cm, and 17000 lux of light yield 1068.82 cm- of leaf area.ABSTRAKTanaman sayuran harus dibudidayakan dengan optimal agar diperoleh hasil yang maksimal. Di wilayah tropis seperti di  Indonesia,  pertumbuhan  tanaman  sayuran  dipengaruhi  oleh  beberapa  faktor  iklim  seperti  kelembaban,  suhu, nutrisi dan cahaya. Untuk memperoleh kondisi yang optimal dan terkendali selama periode pertumbuhan, tanaman sawi dibudidayakan secara hidroponik di dalam greenhouse. Penelitian ini dilakukan untuk mengidentifikasi pola pertumbuhan tanaman sawi (Brassica  rappa var. parachinensis L.) yang dibudidayakan secara hidroponik di dalam greenhouse yang dilengkapi dengan kendali suhu, nutrisi dan cahaya. Tujuan penelitian adalah menentukan kombinasi faktor terbaik yang memberikan pertumbuhan paling optimal. Penelitian dilakukan dengan memberikan tiga perlakuan dengan tiga variasi yaitu suhu (32 °C, 35 °C, dan 38 °C), nutrisi (2 mS/cm, 5 mS/cm, dan 8 mS/cm), dan cahaya (7000 lux, 12000 lux, dan 17000 lux) sehingga terdapat 27 ruang budidaya atau greenhouse dengan iklim mikro yang berbeda. Tingkat pertumbuhan ditentukan berdasarkan luas daun dan diukur selama 48 hari budidaya. Kendali di dalam masing- masing greenhouse dilakukan oleh aktuator pompa, lampu pijar dan lampu TL (Flourescent Lamp). Hasil penelitian menunjukkan suhu, nutrisi dan cahaya berpengaruh pada pertumbuhan tanaman sawi. Dari hasil analisis faktor tunggal, luas daun maksimum dihasilkan pada suhu 35 °C yaitu 565 cm-, nutrisi 5 mS/cm yaitu 639,27 cm- dan cahaya 17000 lux yaitu 697,42 cm-. Secara kombinasi, tingkat pertumbuhan terbaik diperoleh pada perlakuan suhu 35 °C, nutrisi 5 mS/cm, dan cahaya 17000 lux dengan hasil luas daun mencapai 1068,82 cm-.
KAJIAN INPUT ENERGI PADA BUDIDAYA PADI METODE SYSTEM OF RICE INTENSIFICATION Studies on Energy Input in System of Rice Intensification Method of Rice Cultivation Purwantana, Bambang
Jurnal Agritech Vol 31, No 01 (2011)
Publisher : Jurnal Agritech

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Abstract

System of Rice Intensification (SRI) is a rice cultivation method that intensively control and manage macro and micro nutrients as well as irrigation. This paper quantifies and compares the energy uses of SRI and conventional rice cultiva- tion systems. The study was conducted at some SRI’s experimental plots in the districts of Sleman, Kulonprogo, and Bantul, the province of Yogyakarta. The calculation of the energy was based on the farmers’ work schedule, the time required for each operation, the number of laborers, machines, tools, fuel, and all materials and inputs used. The result shows that SRI method consumed 35% less energy to conventional rice cultivation. Energy inputs from seed, water, fertilizer and pesticide were significantly reduces. However, there was higher input of human energy due to compost- ing, land preparation and weeding operations. The specific energy of SRI method was 1.96 MJ ha-1 lower than conven- tional method of 4.43 MJ ha-1. In the SRI method, 56.2 % of energy consumed was classified as direct energy and 43.8% was indirect energy. The SRI method used 61.9 % of renewable energy and 38.1 % of non-renewable energy. The working efficiency in composting and weeding operations should be improved in perspective of machine and tools to reduce the use of human energy.ABSTRAKSystem of Rice Intensification (SRI), merupakan suatu metode budidaya padi secara intensif dengan pengendalian unsur-unsur hara makro dan mikro disertai pengendalian dan pengaturan kebutuhan air. Penelitian ini bertujuan untuk menganalisis penggunaan energi dan mengidentifikasi kemungkinan penghematan energi pada budidaya padi SRI. Pe- nelitian dilakukan di Kabupaten Sleman, Kulonprogo, dan Bantul, Propinsi Daerah Istimewa Yogyakarta. Pengamatan dilakukan pada plot-plot percobaan budidaya padi SRI dengan melakukan audit seluruh input energi selama proses budidaya dan dikomparasikan dengan input energi pada budidaya padi cara konvensional. Hasil penelitian menunjuk- kan bahwa budidaya padi metode SRI menggunakan input energi 35 % lebih kecil daripada input energi pada budidaya padi konvensional. Input energi dari benih, pupuk dan pestisida kimia serta air irigasi berkurang sangat signifikan, meskipun terdapat kenaikan input energi manusia untuk pekerjaan pembuatan kompos, penyiapan lahan dan penyian- gan. Metode SRI termasuk kategori budidaya kurang padat energi dengan energi spesifik 1,96 MJ kg-1, lebih rendah dari metode konvensional yaitu 4,43 MJ kg-1. Berdasar klasifikasi energinya, metode SRI menggunakan 56,2 % jenis energi langsung dan 43,8 % sumber energi tak langsung, 61,9 % energi terbarukan dan 38,1 % energi tak terbarukan. Efisiensi penggunaan alat dan mesin pada pekerjaan pembuatan kompos dan obat serta pemeliharaan tanaman perlu dikembangkan untuk mengurangi kebutuhan tenaga manusia.
The Clay Content Effect on The Formation of Shallow Mole Drainage and The Rate of Lowering Soil Moisture Content Suharyatun, Siti; Purwantana, Bambang; Rozaq, Abdul; Mawardi, Muhjidin
Agritech Vol 34, No 3 (2014)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/agritech.9464

Abstract

Installing shallow mole drainage in the soil is infl uenced by various factors, namely; the physical properties of soil and tools which are used. One of the physical properties of soil that infl uences the formation of the mole drainage is the clay content of soil. This study aimed to explore the condition of the mole drainage formed in paddy soil with different clay contents. The study was conducted in a laboratory scale using a soil bin, a model of mole plough, and soil which was kept homogeneous in the boxes. The experiment was conducted at the Laboratory for Energy and Agricultural Engineering, Agricultural Engineering Department, Universitas Gadjah Mada, Yogyakarta. Mole drainage was installed in 3 paddy soils with different clay content, namely; 13.12% (soil A; loam soil), 41.17% (soil B; clay soil) and 53.36% (soil C; clay soil). The study was conducted by analyzing the geometry of the mole drainage and observing the soil deformation which occurred due to the formation of the mole drainage. The study showed that perfect mole drainages were installed in all of those three types of soil. The mole drainages were quite good and stable with little cracks. Based on the soil crack and fi ssuring of soil, the largest soil deformation has occurred in soil with the highest clay content and the smallest one in soil with the lowest clay content. The characteristics of those three installed mole drainages were almost the same, but they had different effect on the rate of lowering soil moisture content. Here, the mole drainage installed in loam soil is different from which of installed in clay soil. The mole drainage installed in the loam soil did not infl uence the rate of lowering soil moisture content. Contrary, the mole drainage installed in clay soil has effected to increase the rate of lowering soil moisture content.
Sebaran Lengas Tanah Akibat Pembuatan Lorong Pengatus Dangkal pada Tanah Sawah Suharyatun, Siti; Purwantana, Bambang; Rozaq, Abdul; Mawardi, Muhjidin
Agritech Vol 33, No 3 (2013)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/agritech.9559

Abstract

Mole drainage is an alternative which can be used to increase the rate of soil moisture decrease in paddy soil at the end of the rainy season. By using mole drainage, the rate of soil moisture decrease goes up to a certain condition (from saturated to field capacity) which is suitable for early growth of crops. This study aimed at describing changes and distribution of soil moisture in paddy soil in which shallow mole drainage had been formed. Those changes and distribution were used to predict the rate of soil moisture decrease in paddy soil after mole drainage was formed. The study was conducted in the laboratory using a soil bin, a model of mole plough, and soils that was kept homogeneous in the boxes. The experiment was conducted in the Laboratory of Energy and Agricultural Engineering, Agricultural Engineering Department, Gadjah Mada University. The mole drainage was installed in three paddy soils with different clay content, namely 13.12% (A), 41.17% (B) and 53.36% (C). Soil moisture content was measured periodically by using gypsum blocks. The results showed that the three types of soils in which shallow mole drainage was formed had different characteristics of soil moisture changes. The formation of mole drainage in soil with low clay content (A) had no effect for the declining rate of soil moisture. On the contrary, the shallow mole drainage formed in the soil with higher contents of clay B and C influenced the rate of soil moisture decrease. High rate of soil moisture decrease in the soil B and C occurred at the beginning of the formation of mole drainage and went on up to the 3th hours of observation. Based on the distribution of soil moisture at different points at some distances from the center of mole drainage and the equation of the rate of soil moisture decrease found in the experiment, it could be inferred that moles formed in soils B and C could be used as mole drainage and the rate of soil moisture decrease in soil C was cumulatively higher than in soil B.ABSTRAKLorong pengatus merupakan salah satu alternatif guna mengatasi lamanya masa tunggu tanam palawija di lahan sawah pada akhir musim penghujan akibat kadar lengas tanah yang terlalu tinggi. Lorong pengatus dibuat untuk mempercepat laju penurunan kadar lengas sehingga sesuai untuk pertumbuhan awal tanaman palawija. Penelitian ini bertujuan mendeskripsikan perubahan dan sebaran lengas tanah yang terjadi akibat pembentukan lorong pengatus dangkal, untuk digunakan sebagai salah satu dasar memperhitungkan laju penurunan kadar lengas yang terjadi pada tanah sawah yang dibuat lorong pengatus. Penelitian dilakukan dalam skala laboratorium dengan menggunakan soil bin, model bajak lorong, dan tanah di dalam boks yang dijaga homogenitasnya. Penelitian dilaksanakan di Laboratorium Energi dan Mesin Pertanian, Jurusan Teknik Pertanian, FTP-UGM. Lorong pengatus dibuat pada 3 jenis tanah sawah dengan kadar lempung yang berbeda, yaitu 13,12% (tanah A), 41,17% (tanah B) dan 53,36% (tanah C). Pengukuran kadar lengas tanah dilakukan secara periodik menggunakan gypsum blok. Hasil penelitian menunjukkan bahwa ketiga jenis tanah yang dibuat lorong pengatus mempunyai karakteristik perubahan lengas tanah yang berbeda, Pembentukan lorong pengatus pada tanah dengan kadar lempung rendah (tanah A) tidak memberikan pengaruh terhadap laju penurunan lengas tanah, tetapi pada tanah dengan kadar lempung tinggi (tanah B dan C) berpengaruh terhadap laju penurunan lengas tanah. Laju penurunan lengas tanah kumulatif yang tinggi terjadi pada awal pembentukan lorong sampai 30 jam pasca pembentukan lorong. Dari distribusi lengas tanah pada jarak yang berbeda dari pusat lorong dan dari persamaan laju penurunan lengas hasil eksperimen, lorong yang dibuat pada tanah B dan C dapat berfungsi sebagai lorong pengatus. Peningkatan laju penurunan lengas tanah kumulatif tanah C lebih besar dibanding  tanah B.
Pengembangan Gasifier untuk Gasifikasi Limbah Padat Pati Aren (Arenga Pinnata Wurmb) Purwantana, Bambang
Agritech Vol 27, No 3 (2007)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/agritech.9602

Abstract

Sugar palm powder is a raw material for various food products. Solid wastes produced during the powder process- ing have not yet been utilized properly. Gasification of the wastes by converting them into gaseous fuel could be an alternative to solve the waste problem. The objective of this research was to develop downdraft gasifier suitable for solid waste of sugar palm powder. The performance of the gasifier was determined by its temperature distribution, gas composition, gas production, and heat. The result showed that solid waste of sugar palm powder are potential to be used as gasification fuel. The gasification process was optimum at gasifier having greater than 70o tilt angle of pyroly-sis chamber,  180 mm diameter of combustion chamber,  and 200 mm height of reduction chamber, and using air flow rate of 11 m3/h. The performace of the gasification were: (1) average temperature in gasification chamber, combustion chamber, and pyrolysis chamber were 172oC, 353oC, and 135oC, respectively; (2) gas composition of H2, CO, CH4, O2, CO2,  and N2  were 7,4%, 18,1%, 1,5%, 2,7%, 6,8%, and 58,0%, respectively; (3) gas production was18 m /hour; and (4) heat was 2 MJ/kg.ABSTRAKPada proses pembuatan pati aren dihasilkan limbah berupa serat dan ampas dengan jumlah yang besar. Selama ini limbah  tersebut  belum  dimanfaatkan secara  optimal.  Melalui  penelitian  ini  dikembangkan  suatu  proses  gasifikasi limbah padat pati aren untuk membuat bahan bakar berupa gas. Tujuan penelitian adalah mengembangkan gasifier tipe aliran ke bawah (downdraft gasifier) dengan titik berat pada perancangan ruang pirolisa, pembakaran dan reduksi gas. Kinerja gasifikasi diamati berdasarkan karakteristik distribusi suhu, komposisi gas, kapasitas produksi, dan panas yang dihasilkan. Hasil penelitian menunjukkan  bahwa  limbah  padat  pati  aren potensial untuk digunakan sebagai bahan baku gasifikasi. Sudut kemiringan hoper ruang pirolisa lebih besar dari 70o  diperlukan untuk efektifitas aliran proses pembakaran dan reduksi. Berdasar hasil percobaan, proses gasifikasi terbaik diperoleh pada dimensi ruang pembakaran berdiameter 180 mm, dan tinggi ruang reduksi 200 mm pada debit udara 11 m3/jam. Pada kondisi disain dan operasional tersebut diperoleh karakteristik gasifikasi sebagai berikut: (1) suhu rerata ruang gasifikasi 172oC, ruang pembakaran 353oC, ruang pirolisis 135oC, (2) komposisi gas H2 7,4%, CO 18,1%, CH4 1,5%, O2 2,7%, CO2 6,8%, dan N  58,0%, (3) produksi gas 18 m3/jam, (4) panas 2 MJ/kg bahan.
Analisis Kinerja Mesin Pengupas Lada (Piper Nigrum L.) Tipe Silinder Putaran Vertikal Suhendra, Suhendra; Rozaq, Abdul; Purwantana, Bambang
Agritech Vol 31, No 2 (2011)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/agritech.9736

Abstract

White pepper is produced by decorticating the pericarp of the pepper which commonly be done manually or mechani­ cally. A pepper decorticator without soaking process was developed in order to improve quality and capasity of decor­ tication. The decortication mechanism was designed by shearing the pepper on a gap between a static vertical cylinder and a vertical axis rotating tube. This research was done to analyze the decortication and working performances of the machine. Dimension analysis approach was applied in order to develope a mathematical relation to be used for prediction of the machine performance based on their design and operational variables. The machine variables varied were linear speed of tube (v), width of clearance (s), and length of rotated cylinder (L). The material variables were diameter of pepper (D ), decortication force (F ), and density of pepper (ρ ). From the analysis result, there were de­bkbfined mathematical equations for prediction of decorticated pepper (p ), damaged pepper (p ) and working capacity ofkrthe machine (K ). Validation analysis shows that the equations could be used for prediction and determination of themachine performances needed.ABSTRAKLada putih dihasilkan melalui proses pengupasan kulit lada yang dilakukan secara manual atau mekanis. Untuk meng­ atasi masalah rendahnya kapasitas dan kualitas pengupasan telah dikembangkan rancangbangun mesin pengupas kulit lada dengan sistem gesekan pada silinder dengan putaran poros secara vertikal tanpa melalui proses perendaman. Penelitian ini dilakukan untuk menganalisis kinerja pengupasan, kerusakan dan kapasitas kerja mesin. Pendekatan analisis dimensi diterapkan untuk mendapatkan persamaan matematis yang dapat digunakan untuk memprediksi dan merencanakan kinerja mesin berdasarkan variabel rancangbangun dan operasionalnya. Variabel bebas mesin yang di­ variasikan meliputi kecepatan linier silinder (v), lebar celah (s) dan panjang silinder pengupas (L). Variabel bahan yang dipertimbangkan meliputi diameter bahan (D ), gaya pengupasan (F ), dan massa jenis bahan (ρ ). Dari hasil analisis te­bkblah diperoleh persamaan prediksi kinerja mesin yaitu persentase pengupasan (p ), persentase kerusakan (p ) dan kapasi­krtas kerja mesin (K ). Analisis kesesuaian menunjukkan bahwa pada batas keberlakuannya persamaan­persamaan yangdiperoleh dapat diterima dan dapat digunakan untuk memprediksi dan merencanakan kinerja mesin yang diinginkan.
Analisis Potensi Lorong Pengatus Dangkal untuk Percepatan Jadwal Tanam Palawija di Tanah Sawah Suharyatun, Siti; Purwantana, Bambang; Rozaq, Abdul; Mawardi, Muhjidin
Agritech Vol 35, No 4 (2015)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/agritech.9332

Abstract

Installing shallow mole drainage in paddy soil can increase the rate of lowering soil moisture into such a condition which is suitable for the early growth of non-rice crops. This study aimed to analyze the shallow mole drainage installation potential to plant crops early in paddy soil. The study was conducted in a laboratory scale using a soil bin, a model of mole plow, and soil kept homogeneous in boxes. The experiment was conducted at the Laboratory for Energy and Agricultural Machinery, Agricultural Engineering Department, Faculty of Agricultural Technology Universitas Gadjah Mada, Yogyakarta. Mole drainage was installed in 2 paddy soils, with different clay content, namely; 41.17% (soil B) and 53.36% (soil C). Soil moisture content was measured periodically by using gypsum blocks. The analysis showed that the mole drainage installed in soil B was able to speed up the time taken to reach field capacity. At the distance horizontally to the center of mole drainage (x) = 6.5 cm with the depth (z) =5 cm took 72 hours faster than the control. At z =10 needed 92 hours, at z = 15 cm needed 154 hours faster than the control. At the distance horizontally to the center of mole drainage (x) = 11.5 with z = 5 cm took 52 hours, with z = 10 cm took 161 hours, with z = 15 cm took 150 hours faster than the control. The installation of mole drainage in soil C was also able to speed up the time required to reach field capacity. At the distance horizontally to the center of mole drainage (x) = 6.5 cm with the depth (z) = 5 cm took 165 hours, with z = 10 cm took 184 hours, with z = 15 cm took 200 hours faster than the control. At x = 11.5 with z = 5 cm took 144 hours, with z = 10 cm took 154 hours, with z = 15 cm took 192 hours faster than the control. The lesser time required to reach field capacity indicated that mole drainage installed in soil B and C was potential to plant crops early in paddy soil.ABSTRAKLorong pengatus dangkal di lahan sawah berfungsi meningkatkan laju penurunan lengas tanah di lapisan olah, sehingga kondisi tanah yang sesuai untuk pertumbuhan awal tanaman palawija dapat segera tercapai. Penelitian ini bertujuan untuk menganalisis potensi pembentukan lorong pengatus terhadap peluang percepatan jadwal tanam palawija di tanah sawah. Penelitian dilakukan dalam skala laboratorium dengan menggunakan soil bin, model bajak lorong, dan tanah di dalam boks yang dijaga homogenitasnya. Penelitian dilaksanakan di Laboratorium Energi dan Mesin Pertanian, Jurusan Teknik Pertanian, Fakultas Teknologi Pertanian Universitas Gadjah Mada, Yogyakarta. Lorong pengatus dibuat pada 2 jenis tanah sawah bertekstur lempung, dengan kadar lempung yang berbeda, yaitu 41,17% (tanah B) dan 53,36% (tanah C). Pengukuran kadar lengas tanah dilakukan secara periodik menggunakan gypsum blok. Hasil penelitian menunjukkan bahwa pembentukan lorong pengatus pada tanah B dapat mempercepat waktu yang dibutuhkan untuk mencapai kapasitas lapang. Pada jarak horisontal dari pusat lorong (x)=6,5 cm dengan kedalaman (z)=5cm, membutuhkan waktu 72 jam lebih cepat dibanding kontrol, pada z=10 cm membutuhkan 192 jam, pada z=15 cm membutuhkan154 jam lebih cepat dibanding kontrol. Pada x=11,5 membutuhkan waktu 52 jam (z=5cm), 161 jam (z=10 cm), 150 jam (z=15 cm) lebih cepat dibanding kontrol. Pembentukan lorong pengatus pada tanah C juga dapat mempercepat waktu yang dibutuhkan untuk mencapai kapasitas lapang. Pada x=6,5 cm, membutuhkan waktu 165 jam (z=5cm), 184 jam (z=10 cm), 200 jam (z=15 cm) lebih cepat dibanding kontrol. Pada x=11,5 membutuhkan waktu 144 jam (z=5cm), 156 jam (z=10 cm), 192 jam (z=15 cm) lebih cepat dibanding kontrol. Menurunnya waktu yang dibutuhkan untuk mencapai kapasitas lapang menunjukkan bahwa pembentukan lorong pengatus di tanah B dan C berpotensi untuk mempercepat jadwal tanam palawija.