Usman Ahmad
Departemen Teknik Mesin dan Biosistem, Fakultas Teknologi Pertanian, Institut Pertanian Bogor

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PERANCANGAN DAN KONSTRUKSI MESIN SORTASI DAN PEMUTUAN BUAH JERUK DENGAN SENSOR KAMERA CCD Ahmad, Usman; Tjahjohutomo, Rudy; S., Mardison
Jurnal Keteknikan Pertanian Vol. 22 No. 1 (2008): Jurnal Keteknikan Pertanian
Publisher : PERTETA

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Abstract

Citrus is one of important fruits in Indonesia and its production increases every year. However, postharvest equipment for citrus is very limited, leading to low postharvest technology utilization. The objective of this research was to develop a real-time quality evaluation system using a color CCO camera, to be used as an image sensor and processing unit for quality evaluation of the citrus from acquired image. The system consists of a color CGO camera, a computer with an image frame grabber, an image acquisition chamber, a logic control panel, and a software to run all the installed hardware Some important parameters of visual quality of citrus were studied. Five groups of different quality of citrus, obtained from a big trader in Pasar Induk Kramatjati, were used for samples. The images were captured and then analyzed with image processing program using area projectio and RGB and HSI color model algorithms, for the fruit size and color respectively. The results were analyzed to determine whether there were parameters that correlates with weight, sweetness and firmness, to be used for quality evaluation. Visual parameters that figures the real quality of citrus best were then selected to be used for quality parameters to develop a real-time quality evaluation system for citrus in the next step.Keywords: image processing, sortasi, pemutuan, otomatis Diterima: 15 Oktober 2007; Disetujui: 18 Pebruari 2008
KAJIAN PENANGANAN BAHAN DAN METODE PENGERINGAN TERHADAP MUTU BIJI DAN MINYAK JARAK PAGAR (JATROPHA CURCAS L.) Mellyana, Verra; Ahmad, Usman; Widowati, Sri
Jurnal Keteknikan Pertanian Vol. 26 No. 2 (2012): Jurnal Keteknikan Pertanian
Publisher : PERTETA

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ABSTRACT Energy is consumed in many sectors such as industry, transportation, and household. Most of the source of energy nowadays are obtained from fosil, which is predicted available for less than 10-15 upcoming years, and should be replaced by renewable energy. One of potential renewable energy to considered is Jatropha, a plant with seeds containing oil that can be processed into biodiesel. As a part of plant, fruit of Jatropha should be treated properly after harvest to maintain its oil in the seeds, so that good physical and chemical properties of  the oil extracted from the seed can be obtained. This research is aim to develop method of handling of the harvested Jatropha fruits, including its drying, to maintain quality of the seeds and oil resulted from extraction. Different combinations of preparation (fresh, seed and steamed seed) and drying (temperature of 50, 60, 70 oC and natural sun drying), have been investigated. The results showed that the best treatment was seed drying at 70 oC with the drying time of 4.83 hour, oil rate of 40.06%, and oil yield of 28.59%. Quality of the seeds which fulfilled Standard National Indonesia (SNI) 01-1677-1989 were broken seed (0.57%), cracked seed (0.20 %), foreign object (0%), moisture content (6.08%). However, the highest oil extraction (40.06%) was not satisfy SNI 01-1677-1989. This case, quality of castor oil which qualified SNI 01-1904-1990 were oil moisture content (0.23%) and acid value (0.33 mg KOH/g), but refractive index (1.6209), iod number (54.31) and saponification number (67.30) were unqualified. Keywords : Jatropha, drying, seed, castor oil  ABSTRAK Energi digunakan pada berbagai sektor seperti industri, transportasi dan rumah tangga. Sebagian besar sumber energi saat ini diperoleh darifosil, yang diperkirakan tersedia untuk kurang dari 10-15 tahun mendatang, dan harus digantikan oleh energi terbarukan. Salah satu energi terbarukan yang potensial untuk dipertimbangkan adalah jarak pagar, tanaman dengan biji yang mengandung minyak yang dapat diolah menjadi biodiesel. Sebagai bagian dari tanaman, buah Jatropha harus diperlakukan dengan baik setelah panen untuk mempertahankan minyakdalam biji, sehingga diperoleh hasil ekstraksi minyak dengan mutu fisik dan kimia yang baik. Penelitian ini bertujuan untuk mengembangkan metode penanganan panen dari buah Jatropha, termasuk pengeringan, untuk mempertahankan kualitas biji dan minyak hasil ekstraksi. Kombinasi yang berbeda mulai dari penanganan bahan (buah segar, biji dan biji hasil pengukusan) dan proses pengeringan (suhu 50, 60, 70oC dan pengeringan matahari alami), telah diteliti. Hasil penelitian menunjukkan bahwa perlakuan terbaik adalah biji yang dikeringkan pada suhu 70oC dengan waktu pengeringan tercepat (4.83jam), kadar minyak 40.06%, serta rendemen minyak tertinggi (28.59%). Mutu biji telah memenuhi Standar Nasional Indonesia (SNI) 01-1677-1989 diantaranya biji rusak (0.57%), bijipecah(0.20%), benda asing(0%), kadar air(6.08%). Akan tetapi kadar minyak (40.06%) yang merupakan kadar minyak tertinggi dari semua perlakuan ini masih belum memenuhi SNI01-1677-1989. Sedangkan mutu minyak yang memenuhi SNI01-1904-1990adalah kadar air minyak(0.23%) dan bilangan asam(0.33 mgKOH/g) dan yang tidak memenuhi adalah rata-rata indeks bias(1.6209), bilangan iod(54.31) dan bilangan penyabunan(67.30). Kata kunci: Jatropha, pengeringan, biji, minyak jarak
FAIRNESS EVALUATION AND COMPARISON OF CURRENT CONGESTION CONTROL TECHNIQUES. Ahmad, Usman; Bin Ngadi, Md Asri; Bin Isnin, Ismail Fauzi
Indonesian Journal of Electrical Engineering and Computer Science Vol 1, No 1: January 2016
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v1.i1.pp176-181

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Transmission Control Protocol (TCP) is used by many applications on the Internet for the reliable data transmission. TCP does not able to utilize the available link bandwidth quickly and efficiently in High bandwidth short distance (HBSD) and high bandwidth long distance (HBLD) networks. Many congestion control techniques also known as TCP variants are developed to solve these problems in different network environments. In this paper an experimental analysis is done for the performance evaluation of TCP CUBIC, TCP Compound, TCP Reno and High speed TCP in term of Inter and Intra Protocol fairness by using Network Simulator 2 (NS-2). Results show that the performance of TCP CUBIC pathetically down and TCP Compound and TCP Reno shows good performance in term of protocol fairness. However, these congestion control techniques still need more improvement for the utilization of available link bandwidth in HBLD networks and other network resources.
KAJIAN METODE PELILINAN TERHADAP UMUR SIMPAN BUAH MANGGIS (GARCINIA MANGOSTANA) SEMI-CUTTING DALAM PENYIMPANAN DINGIN Ahmad, Usman; Darmawati, Emmy; Refilia, Nur Rahma
Jurnal Ilmu Pertanian Indonesia Vol. 19 No. 2 (2014): Jurnal Ilmu Pertanian Indonesia
Publisher : Institut Pertanian Bogor

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Abstract

Mangosteen can be stored for a relatively long period in low temperature storage, but peel hardening due to lostof moisture makes it difficult to open before consumption. One attempt to solve this problem is the application ofsemi-cutting treatment before storage of the fruits at low temperature. However, semi-cutting will acceleratedeterioration process since it increases fruit respiration and creates a door to microorganism to enter and spoil thefruit. Waxing the fruit after semi-cutting helps to overcome the problems, so the fruit can be stored at lowtemperature for long period, but it can be opened easily before consumption. This research aims to find a suitablemethod of waxing as well as the best wax concentration solution for waxing process. The methods of waxingconducted in this research were dipping and smearing, while the wax concentration in solution for both methodswere 6, 9, and 12%. The results show that smearing the fruit after semi-cutting with 12% wax concentration gave thelongest self life for the mangosteen stored at low temperature, while the fruits were still easier to open afterstorage.
RANCANG BANGUN SISTEM SORTASI CERDAS BERBASIS PENGOLAHAN CITRA UNTUK KOPI BERAS W. Soedibyo, Dedy; Ahmad, Usman; Seminar, Kudang Boro; Subrata, I Dewa Made
Jurnal Keteknikan Pertanian Vol. 24 No. 2 (2010): Jurnal Keteknikan Pertanian
Publisher : PERTETA

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Abstrack Coffee has good prospects as a motor of development in Indonesia agribusiness  and agroindustry, therefore needs to be handled properly and professionally. Grading process in commercial green coffee asgrain commodity is still done manually. This process has the disadvantage of low efficiency, objectivity and the level of consistency. Therefore weneed a machine that can workautomatically to classify the quality of the green coffee by visual inspection. Theobjective of this study was to design the  green coffee sorting machine controlled by a computer based on image processing program consisted of conveyor belt, the image capture station used twodigital cameras, and the parallelsimulator divider. The design of sorting machine was used for the development of the green coffee sorting system that will categorizeinto four quality classes based on the qualifications according to the standard of SCAA ( Specialty Coffee Association of America). Keyword: Sorting Machine, green coffee, image procesing, computer programDiterima: 14 Juli 2010; Disetujui: 11 Oktober  2010
PENGARUH PENYUSUTAN TEMU PUTIH (CURCUMA ZEDOARIA (BERG) ROSCOE) TERHADAP KARAKTERISTIK PENGERINGAN LAPISAN TIPIS Tulliza, Inge Scorpi; Tambunan, Armansyah H.; Ahmad, Usman
Jurnal Keteknikan Pertanian Vol. 24 No. 2 (2010): Jurnal Keteknikan Pertanian
Publisher : PERTETA

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Abstract The objective of this study is to analyze the occurrence of shrinkage during thin layer drying of Temu Putih (Curcuma zedoaria (Berg) Roscoe) and its effects to the drying characteristics. The experiments were conducted using a laboratory scale dryer with data acquisition and equipped with machine vision system.The drying conditions was controlled at temperatures (T) of 50°C, 60°C, 70°C,relative humidity (RH) 20%,30%, 40%, 50% and air velocity 0.78 m/s ? 1.95 m/s with a specific combinations. The results show that the temu putih?s slices were shrinking as the moisture content was decreasing with almost linier correlation.The drying data was used to determine the drying constants using three models, namely Henderson andPabis, Lewis, and Page model. The effects of the shrinkage to the drying characteristics is discussed in term of the relation between surface area ratio (AR) to moisture ratio (MR). Keywords: Drying;Thin Layer drying; Shrinkage; Temu Putih Diterima: 24 Maret 2010; Disetujui: 13 September 2010
PENENTUAN POLA PENINGKATAN KEKERASAN KULIT BUAH MANGGIS SELAMA PENYIMPANAN DINGIN DENGAN METODE NIR SPECTROSCOPY Novita, Dwi Dian; Ahmad, Usman; ., Sutrisno; Budiastra, I Wayan
Jurnal Keteknikan Pertanian Vol. 25 No. 1 (2011): Jurnal Keteknikan Pertanian
Publisher : PERTETA

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Abstract Pericarp hardening of mangosteen fruit has correlation with the decrease in moisture content due to transpiration and respiration during storage.  The change of pericarp moisture content during storage may be determined nondestructively using near infrared (NIR) spectroscopy. The objectives of this study were to build calibration model of NIR reflectance to predict the moisture content of the pericarp, and to determine the pattern of pericarp hardening based on change of moisture content during storage using NIR reflectance. NIR reflectance spectra were obtained from fruits stored at 8ºC, 13ºC, and room temperature.  Calibrations were built using partial least squares (PLS) and artificial neural network (ANN) models.  Results of analysis indicated that pericarp moisture content could be predicted well by NIR reflectance using the calibration model of PLS for mangosteen stored at 8ºC, 13ºC, and room temperature. The pattern of pericarp hardening based on change of moisture content also could be determined using NIR reflectance for mangosteen stored at 13ºC and room temperature. Keywords : mangosteen fruit, pericarp hardening, moisture content NIR spectroscopy, PLS, ANN Abstrak Pengerasan kulit buah manggis memiliki korelasi dengan penurunan kadar air kulit buah akibat dari proses transpirasi dan respirasi buah selama penyimpanan. Perubahan kadar air kulit buah selama penyimpanan bisa ditentukan secara non-destutive dengan menggunakan near infrared (NIR) spectroscopy. Tujuan penelitian ini adalah menyusun model kalibrasi reflektan NIR untuk memprediksi kadar air kulit buah manggis, serta untuk menentukan model pengerasan kulit buah berdasarkan perubahan kadar air selama penyimpanan menggunakan reflektan NIR. Spektra reflektan NIR diambil dari buah manggis yang disimpan pada suhu 8oC, 13oC dan suhu ruang. Kalibrasi dibangun dengan menggunakan model partial least squares (PLS) dan artificial neural network (ANN). Hasil analisis mengindikasikan bahwa kadar air kulit buah dapat diprediksi secara baik dengan reflektan NIR menggunakan model kalibrasi PLS untuk buah manggis yang disimpan pada suhu 8oC, 13oC dan suhu ruang. Model pengerasan kulit buah berdasarkan perubahan kadar airnya juga dapat ditentukan dengan reflektan NIR untuk buah manggis yang disimpan pada suhu 13oC dan suhu ruang. Kata kunci : buah manggis, pengerasan kulit, NIR spectroscopy, PLS, ANNDiterima: 19 Oktober 2010; Disetujui: 10 Maret 2011  
PENGEMBANGAN ALOGARITMA PENGOLAHAN CITRA UNTUK MENGHINDARI RINTANGAN PADA TRAKTOR TANPA AWAK Ahmad, Usman; ., Desrial; Subrata, I Dewa Made; Annas, Sjahrul
Jurnal Keteknikan Pertanian Vol. 24 No. 2 (2010): Jurnal Keteknikan Pertanian
Publisher : PERTETA

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AbstractUnmanned 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 2010
PELAPIS NANOKOMPOSIT UNTUK PENGAWETAN SALAK PONDOH TEROLAH MINIMAL Marpaung, Monika; Ahmad, Usman; S, Nugraha Edhi
Jurnal Keteknikan Pertanian Vol. 3 No. 1 (2015): Jurnal Keteknikan Pertanian
Publisher : PERTETA

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AbstractMinimally-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 2015
DOSIS BLANSIR UNTUK MEMPERPANJANG UMUR SIMPAN DAGING BUAH KELAPA KOPYOR Antu, Muhammad Yusuf; Hasbullah, Rokhani; Ahmad, Usman
Jurnal Penelitian Pascapanen Pertanian Vol 13, No 2 (2016): Jurnal Penelitian Pascapanen Pertanian
Publisher : Balai Besar Penelitian dan Pengembangan Pascapanen Pertanian

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21082/jpasca.v13n2.2016.91-98

Abstract

Kelapa kopyor adalah salah satu jenis kelapa eksotik yang memiliki nilai ekonomi tinggi. Teknologi penyimpanan daging buah segar kelapa kopyor belum tersedia. Daging buah kelapa kopyor cepat mengalami kerusakan, yang ditandai dengan cepat berkembangnya mikroba pembusuk. Penelitian ini bertujuan untuk mendapatkan dosis blansir dalam memperpanjang umur simpan daging buah kelapa kopyor. Buah kelapa kopyor diperoleh dari populasi kelapa kopyor Kalianda Lampung Selatan, dan dikemas menggunakan kemasan plastik polypropylene (PP). Perlakuan yang digunakan adalah dosis blansing : 0 menit (tanpa blansir), 5 menit dan 10 menit suhu 75 oC. Daging kelapa kopyor di blansir pada suhu 75 oC selama 5 menit, 10 menit, dan tanpa blansir. Karakteristik mutu yang diamati adalah total padatan terlarut (TPT), pH, asam lemak bebas (ALB), total mikroba, indeks kecerahan, dan uji organoleptik. Hasil penelitian menunjukkan bahwa blansir 10 menit mampu mempertahankan mutu hingga penyimpanan 7 hari suhu kamar. Hal ini ditunjukkan dengan nilai asam lemak bebas dan total mikroba masih dibawah ambang batas, serta hasil evaluasi sensori warna, aroma, serta rasa masih dalam kisaran suka.