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Analisis Rekayasa dan Karakterisasi Briket Bahan Bakar dari Limbah Serat Kenaf Sudarja, Sudarja
Jurnal Semesta Teknika Vol 12, No 1 (2009): MEI 2009
Publisher : Jurnal Semesta Teknika

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The amount of rejected hibiscus cannabinus fiber reaches 30% during harvesting and 10% of the fiber bought by industries because they are not satisfied the quality requirement. In other words, 37% of the harvested hibiscus cannabinus fiber is rejected and become waste. On the other hand, the society need alternative fuel instead of fossil fuel due to its availability and high-price. Therefore, a study on the utilization of hibiscus cannabinus fiber waste for alternative fuel is urgently required. The main materials used in this research are hibiscus cannabinus fiber waste and starch glue. The first step is producing star-coal by burning the hibiscus cannabinus fiber in a closed tube (chamber) followed by producing starcoal briquette by blending starcoal powder and starch glue, and finally, pressing it in a pressing machine. The characteristic being studied are: water content (comply to ASTM-D-3173), calorific value (ASTM D-2015 and ASTM D-5865-03), and ash content (ASTM D-3174). The result of the research shows that the average calorific value of hibiscus cannabinus fiber waste is 6595,65 kal/gram while that of the briquette compacted Â at 1090 psi or above was 7394,14 kal/gram. The average water content was 10,9%, and ash content is 31,67%. Advanced study concerning the percentage of fly ash and economic aspects was recommended in order to justify its feasibility.

Pengaruh Fraksi Udara Terhadap Koefisien Perpindahan Kalor Kondensasi Refrigeran Petrozon Rossy-22 Di Dalam Pipa Tegak Sudarja, Sudarja; Purnomo, Purnomo; Prajitno, Prajitno
Jurnal Semesta Teknika Vol 10, No 2 (2007): NOVEMBER 2007
Publisher : Jurnal Semesta Teknika

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Petrozon Rossy-22 is one of hydrocarbon refrigerants which environmentally safe, since there is no effect on either ozone depletion or global warming. In the refrigeration cycle, imperfect vacuuming process or other factors that permit circulation of air taken place in the system predicted influencing heat transfer rate in condenser. Therefore, research on the influence of air fraction against condensation heat transfer coefficient of Petrozon Rossy-22 inside vertical pipe to be done. A modified refrigeration system of vapor compression was applied in this research, where the condensation was done in the 2 meters straight vertical condenser (double pipe heat exchanger, that further called as test section). The diameter of internal and external pipe were Â¾â and 1 Â¼â respectively. Electric heater was installed on upstream of the test section. Mixture of air- refrigerant was flowed downward inside internal pipe, while cooling water was flowed upward through annulus. The varied parameters were: air fraction, air-refrigerant and cooling water flow rate. The result of the research indicated that condensation heat transfer coefficient significantly decreased when air fraction increased. The proposed empiric equation is : Â Â Â Â Â Â Nu = 0.0138. (1-w)8.8198. Re0.7941. Pr4.7315with determination coefficient of 0.6927 and average absolute deviation of 17.65 %. The equation was for Re= 6.922-12.953, Pr= 2,008-2,696, and w= (0,25-1)%.

Pengolahan Limbah Industri Sawit Sebagai Bahan Bakar Alternatif Sudarja, Sudarja; Diharjo, Kuncoro; Sutapa, J Pramana Gentur
Jurnal Semesta Teknika Vol 10, No 1 (2007): MEI 2007
Publisher : Jurnal Semesta Teknika

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pengolahan buah sawit di industri sawit menyisakan limbah serat buah sawit yang menumpuk di lingkungan perusahaan, dan mayoritas hanya digunakan sebagai urug atau dibakar. sebaliknya, masyarakat membutuhkan bahan bakar alternatif pengganti bbm, mengingat ketersediaan bbm yang makin menipis dan harganya relatif mahal. oleh karena itu kajian tentang pengolahan limbah biofiber (serat sawit) sebagai bahan bakar alternatif dipandang penting dan mendesak untuk dilakukan.Bahan utama penelitian adalah limbah sawit, dan perekat pati. serat dan cangkang sawit yang memiliki kandungan c tinggi diarangkan, yaitu dibakar pada tabung tertutup (menggunakan retort). selanjutnya dibentuk briket arang dilakukan dengan mencampur serbuk arang dengan perekat pati kemudian ditekan pada cetakan dengan mesin pres. pengujian yang dilakukan terhadap briket arang ini meliputi uji: kadar air (berdasarkan astm d-3173), nilai kalor (astm d-5865), kadar abu (astm d-3174), kadar zat menguap (astm d-3175 )dan kadar karbon terikat (astm d-3172). Hasil penelitian menunjukkan bahwa briket arang yang terbuat dari campuran cangkang dan serat sawit memiliki nilai kalor rata-rata 7.121,57 k kal/kg, kadar air rata-rata 8,9 %, kadar zat menguap rata-rata 18,43% dan kadar abu rata-rata 4,46%. untuk menentukan kelayakan penggunaan briket arang dari limbah sawit ini, perlu dilakukan dua penelitian lanjutan, yaitu tentang persentase abu terbang dan uji ekonomis.Â Â

Pengaruh Lokasi Ketebalan Maksimum Airfoil Simetris Terhadap Koefisien Angkat Aerodinamisnya Nurcahyadi, Teddy; Sudarja, Sudarja
Jurnal Semesta Teknika Vol 11, No 1 (2008): MEI 2008
Publisher : Jurnal Semesta Teknika

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Airfoil performance data is regarded as highly valuable data in its wide area of application since it will help the designer, for examples; to predict the influence of rear spoiler mounting to the maneuverability and top speed of racing car, the thrust and fuel consumption needed for an aircraft to take off and cruise, or the power delivered by a wind turbine rotor at certain wind speed. The performance of airfoil, which is measured with its lift and drag coefficient, is greatly affected by its geometry and operating condition. The influence of various geometric and operational parameters to the airfoil performance is needed to be studied experimentally and the airfoil performance data obtained can be added to enrich the airfoil performance data base. The experiment was done by testing airfoil models by lift force direct measurements in a sub-sonic wind tunnel.Â The type of airfoil used in this experiment is the symmetric airfoil with maximum thickness location as the geometric parameter and angle of attack with wind speed as the operational parameter being investigated for their influence to the lift and drag coefficient. The maximum thickness location was varied in 30%, 40%, and 50% of chord length measured from leading edge. The angle of attack was varied from 0o to 20o with 4o increments. The wind speed was varied from 10 m/s to 20 m/s with 2 m/s increments.Â Parameters being measured were the free stream velocity, and the lift force. The result of the research shows that the best airfoil performance with lift coefficient 3,16 is achieved by the airfoil that has maximum thickness location in 40% of its chord length measured from its leading edge and operates at 20o angle of attack and 8,9Â m/s free stream velocity.

Pembuatan Alat Uji untuk Mengikat Partikel Logam yang Terkandung dalam Pelumas Akibat Gesekan Mesin Sukamta, Sukamta; Sudarja, Sudarja; Nurdarojat, Nurdarojat; Prasetyo, Agung
Semesta Teknika Vol 17, No 2 (2014): NOVEMBER 2014
Publisher : Semesta Teknika

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One of the factors that can affect to the quality of lubricantion is metal particle content due to friction of engine parts.Â Metal particle in lubricanting oil could damage the engine parts, so it is neccessary to reduce the metal particle content which mingled in lubricant oil. The experiment was conducted in laboratory scale using power magnetic type ring neodymium possessing diameter of 19 mm and thickness of 2 mm. The experiment was conducted by flowing the lubricanting oil containing metal particle continually and put the magnets in engine so that the metal particle will be taken up by the magnets. The experiment usedÂ three variations of time (5, 10 and 15 minutes) and three variations of valve to controlling the flow rate using. The highestÂ absortion of metalÂ particle was reached on opening valve 30 for 15 minutes. When volume the flow rate was 200 ml/s and the time was 15 minutesÂ the result of absortion was 7.48 % (magnet A), meanwhile for volume the flow rate 180 ml/s and the time was 15 minutes resulted in particle absortion of about 7.37 % (magnet B). When Magnet A and B used together and at the same flow rate and time, i.e. 180 ml/s time 15 minutes, resulted the particle absortion about 17.98 %.

Analisis Unjuk Kerja Boiler Feed Pump Turbine Untuk Kapasitas Ketel Uap 2000 Ton/Jam Di PLTU Cirebon Jawa Barat Sukamta, Sukamta; Sudarja, Sudarja; Wathon, Muhammad Mujaddid Ighna
Semesta Teknika Vol 18, No 1 (2015): MEI 2015
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Boiler feed pump turbine (BFPT) has an important role in the circulating of demin water from deaerator to the separator ofÂ steam power plant operations (PLTU) in Cirebon. Flow rate, temperature andÂ pressure were important parameters in boiler feed pump process. Based on the BFPT function, it was necessary to do the analysis interpretation of the performance BFPT. Data needed for evaluation include pressure and temperature on the suction, pressure and temperature on the discharge, and flow capacity. In this study, the data were taken starting in January to December 2014. Data processing was performed using a centrifugal pump calculations, presented in tables and graphs using MS Excel. Analysis of data using qualitative interpretation of quantitative data. BFPT efficiency during operations in 2014 decreased in February - March amounted to 17.91% (BFPT A) and 18.04% (BFPT B). BFPT A highest efficiency obtained in January amounted to 73.76%, the lowest in March amounted to 55.45%. The highest efficiency BFPT B in February amounted to 72.94%, the lowest in March amounted to 54.9%. Change of Performance BFPT occur due to changes load generator power plant that led to the pressure changeÂ and flow capacity. Other factors that degrade the performance because BFPT was operated continuously for 24 hours and the age ofÂ BFPT sufficient oldÂ cause decrease in pump performance.

Perilaku Antarmuka Berdasarkan Data Beda Tekanan pada Peristiwa Kondensasi Aliran Uap Dengan Pendinginan dari Luar Searah pada Pipa Horisontal Berbasis Domain Waktu Sukamta, Sukamta; Ari Dwiearto, Hasan Asy; Sudarja, Sudarja
Semesta Teknika Vol 21, No 1 (2018): MEI 2018
Publisher : Semesta Teknika

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.211214

A two-phase flow pattern experiment on the condensation event of steam flow with external cooling based on the measurement of pressure difference within a horizontal pipe is carried out by varying the superficial velocity. Annulus pipes with inner pipe material made of copper and outer pipe made of galvanized iron (GIP) within an insulation of 10 mm thick were used in this experiment. The length of the pipe is 1.6 meters, outer diameter of 4 inch and inner diameter of 17 mm. The two-phase flow pattern was investigated based on differential pressure fluctuations between the inlet and outlet. To support the observation, flow pattern visualization was performed using a transparent pipe with a diameter of Â¾ inch and a length of 1.3 meters connected to the test pipe section. The superficial vapor velocity was carried out from JG = 0.0689 m/s to JG = 1,9117 m/s. The results showed stratified flow patterns for the lowest superficial velocity and also obtained wavy, wavy-slug, and slug. Annular flow patterns can not be observed in this experiment. In general, increasing superficial velocity of steam will cause a significant increase in pressure fluctuations.

Pengolahan Limbah Industri Sawit Sebagai Bahan Bakar Alternatif Sudarja Sudarja; Kuncoro Diharjo; J Pramana Gentur Sutapa
Semesta Teknika Vol 10, No 1 (2007): MEI 2007
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.v10i1.855

pengolahan buah sawit di industri sawit menyisakan limbah serat buah sawit yang menumpuk di lingkungan perusahaan, dan mayoritas hanya digunakan sebagai urug atau dibakar. sebaliknya, masyarakat membutuhkan bahan bakar alternatif pengganti bbm, mengingat ketersediaan bbm yang makin menipis dan harganya relatif mahal. oleh karena itu kajian tentang pengolahan limbah biofiber (serat sawit) sebagai bahan bakar alternatif dipandang penting dan mendesak untuk dilakukan.Bahan utama penelitian adalah limbah sawit, dan perekat pati. serat dan cangkang sawit yang memiliki kandungan c tinggi diarangkan, yaitu dibakar pada tabung tertutup (menggunakan retort). selanjutnya dibentuk briket arang dilakukan dengan mencampur serbuk arang dengan perekat pati kemudian ditekan pada cetakan dengan mesin pres. pengujian yang dilakukan terhadap briket arang ini meliputi uji: kadar air (berdasarkan astm d-3173), nilai kalor (astm d-5865), kadar abu (astm d-3174), kadar zat menguap (astm d-3175 )dan kadar karbon terikat (astm d-3172). Hasil penelitian menunjukkan bahwa briket arang yang terbuat dari campuran cangkang dan serat sawit memiliki nilai kalor rata-rata 7.121,57 k kal/kg, kadar air rata-rata 8,9 %, kadar zat menguap rata-rata 18,43% dan kadar abu rata-rata 4,46%. untuk menentukan kelayakan penggunaan briket arang dari limbah sawit ini, perlu dilakukan dua penelitian lanjutan, yaitu tentang persentase abu terbang dan uji ekonomis.

Kaji Eksperimental Efektifitas Penyerapan Limbah Cair Industri Batik Taman Sari Yogyakarta Menggunakan Arang Aktif Mesh 80 dari Limbah Gergaji Kayu Jati Sudarja , Novi Caroko
Semesta Teknika Vol 15, No 1 (2012): MEI 2012
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.v15i1.443

Utilization of teak wood saw scratches can be optimized by processing it becomes active charcoal which possesses higher economic value. The purpose of this study is to obtain mesh 80 activated charcoal made from teak sawing industrial waste and to determine it’s effectiveness in adsorbing heavy metals pollutant Cd, Pb, Cr, and colouring agent in liquid waste of batik industries. The charcoal is produced at ~5000 oC retort either for 4 hours or until white colour smoke does not appear. Charcoal was activated using H2SO4 at temperature of 5000 oC for 30 minutes in a furnace. There were 2 variables in this study, i.e weight of the activated charcoal (10, 15, 20 grams) and duration of the stirring (5, 10,15 minutes). Result of the research shows that activated charcoal made from teak wood saw scratches can be used as adsorbent in the liquid waste of batik industries such as heavy metals Cd, Pb, Cr, and dark colour. The colour gradation was found to decrease from 12600 TCU to 198 TCU, Pb content decrease from 0,189 mg/l to less than 0,0093 mg/L, Cd content decrease from 0,213 mg/l to less than 0,0093 mg/L, while Cr content decrease from 2,03 mg/l to 0,4205 mg/l.

Pengaruh Grain Size Arang Aktif dari Bahan Limbah Industri Sagu Aren terhadap Penyerapan Polutan Limbah Batik Sudarja , Novi caroko , Kuncoro Diharjo
Semesta Teknika Vol 14, No 1 (2011): MEI 2011
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.v14i1.589

Sago palm industries leave large amount of wood waste that is about 30% of the volume of tree trunks, 20% in large size which can be used for the handcraft and about 10% in small-size which only wasted. On the other hand, batik industries produce hazardous and toxic waste (B3), that should be neutralized since this liquid waste are bad smell and hard color, and even toxity (contain various kinds of chemical elements and heavy metals such as Mercury (Hg), Lead (Pb), Chromium (Cr), Cadmium (Cd), and Copper (Cu)) and if the elements are absorbed by human body exceeds the threshold point, it would be dangerous. Therefore, experiment on activated carbon engineering and its use in adsorbing the B3 batik liquid waste is urgently required. The main objective of the experiment is to know the adsorbsion effectivity of activated carbon in adsorbing the batik liquid waste. The main material used in producing activated carbon is waste palm tree trunks. The main material is heated to be charcoal in retort for about 5 hours, temperature around 500 º C. Furthermore, charcoal is crushed finely and screened in sizes of mesh 25, 35 and 50. Carbon powder then chemically activated using H2SO4 solution by heating in 500 ˚C for about 30 menutes. Finally this activated carbon used for adsorbing the hard colour and heavy metal (Pb, Cr, Cd) in the batik waste water. This research concluded that the sago aren industrial waste may be an alternative material for activated carbon which is effective in adsorbing the hard colour and hazardous heavy metal. Higher mesh size (grain size) of activated carbon give higher adsorbsion in colour and heavy metal. Activated carbon in mesh 25 adsorbed 68.59% Cd, 16.65% Cr, and 100% Pb, mesh 35 adsorb 76.25% Cd, 37.55% Cr and Pb at 100%, while mesh 50 adsorb 81.61% Cd, 58,33% Cr, and 100% Pb.

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