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"ABSTRAKPenelitian torrefaksi bonggol jagung telah dilakukan untuk mempelajari pengaruh laju alir nitrogen terhadap yield dan komposisi bonggol jagung yang dihasilkan melalui proses torrefaksi. Pengaruh laju alir nitrogen diteliti dengan memvariasikan laju alir nitrogen sebesar 0,3 L/min, 0,5 L/min, dan 0,7 L/min dengan masing-masing variasi laju alir nitrogen dilakukan pada 3 variasi suhu torrefaksi, yaitu 250oC, 275oC, dan 300oC. Proses torrefaksi berlangsung di reaktor tubular dengan holding time 20 menit, heating rate 10oC/menit, dan total massa umpan 15 gram. Identifikasi pengaruh laju alir nitrogen dilakukan dengan menganalisis bonggol jagung hasil torrefaksi dengan menggunakan karakterisasi FTIR, Ultimate, dan Thermogravimetri Analysis (TGA). Hasil penelitian ini menunjukkan bahwa terdapat pengaruh laju alir nitrogen terhadap yield dan komposisi bonggol jagung hasil torrefaksi. Semakin besar laju alir nitrogen maka yield dari bonggol jagung hasil torrefaksi akan semakin kecil. Semakin besar laju alir nitrogen, kandungan oksigen dalam bonggol jagung hasil torrefaksi akan semakin berkurang dan kandungan karbonnya meningkat. Kandungan oksigen setelah torrefaksi menurun hingga 38% pada saat suhu torrefaksi 300oC dengan laju alir nitrogen sebesar 0,7 L/min sementara kandungan karbonnya meningkat hingga 44% bila dibandingkan dengan bonggol jagung umpan torrefaksi, rasio C/O meningkat dari 0,95 menjadi 2,19 dan rasio C/H meningkat dari 6,9 menjadi 13,99. Berdasarkan karakterisasi FTIR seiring semakin besar laju alir nitrogen maka gugus fungsi fenol, guaiacol, catechol, dan ether akan semakin tinggi. Data karakterisasi TGA menunjukan bahwa laju alir nitrogen tidak berpengaruh terhadap suhu pirolisis dari bonggol jagung yang sudah ditorrefaksi. Suhu torrefaksi adalah faktor yang mempengaruhi dari suhu pirolisis bonggol jagung yang sudah ditorrefaksi.

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ABSTRACTTorrefaction of corn cobs has been carried out to study the effect of nitrogen flow rate on yield and torrefied corn cobs composition produced through torrefaction. The effect of nitrogen flow rate was investigated by varying the nitrogen flow rate by 0,3 L/min, 0,5 L/min, and 0,7 L/min with each nitrogen flow rate variation performed on 3 torrefaction temperature variations are 250oC, 275oC, and 300oC. Torrefaction process takes place in a tubular reactor with a holding time of 20 minutes, a heating rate of 10oC/ minute, and a total feed mass of 15 grams. Identification of the effect of nitrogen flow rate was carried out by analyzing the torrefaction corn cobs using FTIR, Ultimate, and Thermogravimetric Analysis (TGA) characterizations. The results of this study indicate that nitrogen flow rate affects yield and torrefied corncobs composition. The greater the nitrogen flow rate, the lower is the yield of torrefied corn cobs. The greater the flow rate of nitrogen, the lower is the oxygen content in the corn cobs and the higher is the carbon content. The oxygen content after torrefaction decreased up to 38% when the torrefaction temperature was carried out at 300oC with a nitrogen flow rate of 0.7 L/min while the carbon content increased by 44%, the C/O ratio increased from 0,95 to 2,19 and the C/H ratio increased from 6,9 to 13,99. Based on FTIR characterization, increasing nitrogen flow rate increases the functional groups furan, phenol, guaiacol, catechol, and ether. Based on the TGA characterization, the nitrogen flow rate did not affect the pyrolysis temperature of the torrefied corn cobs. Torrefaction temperature is a factor that influences the pyrolysis temperature of torrefied corn cobs."

"Sebagai upaya memenuhi kebutuhan bahan bakar penerbangan yang meningkat, sintesis bioavtur dari bahan biomassa lignoselulosa bisa menjadi solusi saat ini. Bonggol jagung sebagai bahan baku dipilih karena kelimpahannya di Indonesia mencapai 7,2 juta ton/tahun dan kandungan holoselulosa yang tinggi sehingga akan menguntungkan saat dikonversi menjadi bio-oil dengan pirolisis. Tujuan penelitian ini untuk mendapatkan analisis kandungan bio-oil dan mendapatkan analisis literatur potensi senyawa yang dominan pada langkah peningkatan mutu bio-oil dan katalisnya dari penelitian eksperimental. Pirolisis ditempuh dengan laju pemanasan rendah sebesar 50C/menit hingga temperatur 5000C dengan kecepatan pengaduk 100 rpm. Berdasarkan analisis GC-MS, komposisi senyawa terbanyak pada bio-oil berupa asam benzoat sebesar 44,45%, yang terbentuk dari oksidasi aldehid yang didahului oleh oksidasi alkohol. Ditinjau dari analisis NMR, ikatan kimia dominan yang terdeteksi ialah membentuk siklopentenon, dengan ikatan C pada siklopentena dan karbonil keton yang masing-masing sebesar 55,61% dan 34,81% pada C-NMR, serta ikatan H pada siklopentena dan C-alfa di keton dengan kelimpahan 47,41% dan 25,19% pada H-NMR. Pembentukan siklopentenon memperlihatkan ciri khas proses slow pyrolysis dengan menghadirkan lebih banyak reaksi siklisasi yang terjadi dari hasil dehidrasi cincin glukosa yang terbuka. Bio-oil dengan dominan siklopentenon ini merupakan basis awal untuk pembentukan bioavtur dengan densitas dan nilai kalor yang tinggi seperti bi(siklopentana). Berdasarkan tinjauan pustaka, rute mekanisme reaksi upgrading dengan katalis dapat dilakukan melalui urutan proses hidrogenasi dengan katalis Cu-Ni-Al dengan yield siklopentanon 95,8%, kondensasi aldol siklopentanon dengan katalis MgO-ZrO2 mampu mencapai yield 2-siklopentilidin-siklopentanon sebesar 84,6%, dan hidrodeoksigenasi disertai katalis Ni/SiO2 menghasilkan bi(siklopentana) dengan yield sebesar 93%. Katalis untuk reaksi hidrogenasi dan hidrodeoksigenasi harus bersifat asam dan untuk reaksi kondensasi aldol bersifat asam-basa. Sebagai produk bioavtur potensial berupa bi(siklopentana) dengan rasio H/C sebesar 1,8 dinilai telah mendekati bioavtur komersial dengan rasio H/C 1,92. Kuantifikasi biomassa yang terkonversi menjadi bioavtur potensial berupa bi(siklopentana) melalui mekanisme senilai 15,96%.

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To fulfill the need of aviation fuel, the synthesis of bioavtur from lignocellulosic biomass can be the current solution. Corn cobs as raw material was chosen because of its potential abundance in Indonesia reaching 7.2 million tons/year and high holocellulose content so that it will be more profitable when converted to bio-oil by pyrolysis. The purpose of this study is to obtain the the bio-oil compositions analysis and obtain a literature analysis of the potential of dominant compounds in the step of improving the quality of bio-oil and its catalysts from experimental research. Pyrolysis is pursued at a low heating rate of 50C/min to a temperature of 5000C with a stirring speed of 100 rpm. Based on GC-MS analysis, the composition of most compounds in bio-oil is benzoic acid with 44.45%, which is formed from oxidation of aldehydes preceded by oxidation of alcohol. In terms of the NMR analysis, the dominant chemical bonds detected were to form cyclopentenone, with C bonds on cyclopentene and carbonyl ketones which were 55.61% and 34.81% on C-NMR, and H bonds on cyclopentene and C-alpha to ketones with an abundance of 47.41% and 25.19% in H-NMR, respectively.The formation of cyclopentenone shows the special characteristics of slow pyrolysis process by presenting more cyclization reactions that occured from the dehydration results of an opened-glucose ring. Bio-oil with cyclopentenone dominant composition is the initial basis for bioavtur synthesize with high density and high heating value characteristics such as bi(cyclopentane). Based on literature review, the mechanism of upgrading reactions with catalysts can be carried out through a sequence of hydrogenation processes with a Cu-Ni-Al catalyst with a cyclopentanone yield of 95.8%, aldol condensation of cyclopentanone with MgO-ZrO2 catalyst was able to reach a yield of 2-cyclopentylidine-cyclopentanone for 84, 6%, and hydrodeoxygenation with Ni/SiO2 catalyst produced bi(cyclopentane) with a yield of 93%. The catalyst for the hydrogenation and hydrodeoxygenation reactions must be acidic and for the aldol condensation reaction is acidic-base. As a potential bioavtur product in the form of bi(cyclopentane) with an H/C ratio of 1.8, it is considered to have approached a commercial bioavtur with an H/C ratio of 1.92. Quantification of biomass converted into bi(cyclopentane) as bioavtur potential was 15.96%."

"Penelitian slow co-pyrolysis bonggol jagung dan plastik polipropilena telah dilakukan untuk mempelajari pengaruh laju alir gas pembawa terhadap yield dan komposisi bio-oil yang dihasilkan. Pengaruh laju alir gas pembawa diteliti dengan memvariasikan laju alir nitrogen sebesar 400 mL/menit, 500 mL/menit, dan 600 mL/menit dengan masing-masing variasi laju alir nitrogen dilakukan pada 3 rasio komposisi bonggol jagung dan plastik polipropilena, yaitu 0 :100 , 50 :50 , dan 100 :0 . Proses slow co-pyrolysis berlangsung di reaktor tangki berpengaduk, dengan suhu akhir 500°C, holding time 10 menit, heating rate 5oC/menit, dan total massa umpan 100 gram. Identifikasi pengaruh laju alir gas pembawa dilakukan dengan menganalisis bio-oil fasa polar dan nonpolar menggunakan FTIR, GC-MS, dan H-NMR.

Hasil penelitian ini menunjukkan terdapat pengaruh laju alir gas pembawa terhadap yield dan komposisi bio-oil hasil slow co-pyrolysis bonggol jagung dan plastik polipropilena. Semakin besar laju alir nitrogen menghasilkan yield bio-oil yang semakin besar dan yield char yang semakin rendah. Yield bio-oil tertinggi sebesar 47,9 mL pada laju alir nitrogen 600 mL/menit, sedangkan efek sinergetik terbaik sebesar 35 pada laju alir nitrogen 400 mL/menit. Berdasarkan karakterisasi GC-MS dan H-NMR seiring semakin besar laju alir nitrogen maka gugus fungsi alkana semakin rendah dan alkena semakin tinggi pada bio-oil nonpolar, serta gugus fungsi karboksilat semakin rendah dan gugus fungsi furan, fenol, guaiacol, catechol semakin tinggi pada bio-oil polar.

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Research that focused on slow co pyrolysis of corn cobs and polypropylene plastic has been done to study the effect of carrier gas flow rate on yield and composition of bio oil. The effect of carrier gas flow rate was investigated by varying nitrogen flow rate of 400 mL min, 500 mL min and 600 mL min with each variation performed on 3 ratio of corn cobs and polypropylene plastic are 0 100 , 50 50 , and 100 0 . The slow co pyrolysis process takes place in a stirred tank reactor, with final temperature of 500°C, holding time of 10 minutes, heating rate of 5oC min, and total mass of feed 100 grams. Identification of the effect of carrier gas flow rate is done by analyzing polar and nonpolar phase bio oil using FTIR, GC MS, and H NMR.

The results of this study indicate that there is an effect of carrier gas flow rate on yield and bio oil composition of slow co pyrolysis of corn cobs and polypropylene plastic. The greater the nitrogen flow rate results in greater bio oil yield and lower yield char. The highest bio oil yield was 47.9 mL at nitrogen flow rate of 600 mL min, while the best synergetic effect was 35 at nitrogen flow rate of 400 mL min. Based on the characterization of GC MS and H NMR as the greater the nitrogen flow rate the alkane functional group is lower and the higher the alkene in nonpolar bio oil, and the lower carboxylic functional groups and the furan, fenol, guaiacol, catechol functional groups are higher in polar bio oil. "

"Pola penjadwalan tanam yang kurang tepat dapat menyebabkan penurunan produksi dan tidak sesuainyapasokan sehingga menimbulkan penumpukan produk yang mempengaruhi penurunan harga. Risiko yangdiakibatkan oleh kesalahan tersebut tidak hanya diderita oleh produsen tetapi juga akan mempengaruhi kinerja organisasi lain yang terhubung dalam jaringan rantai pasok. Oleh karena itu perlu adanya manajemenpenjadwalan yang optimal untuk dapat menanggulangi kemungkinan terjadinya resiko tersebut. Dalam artikel ini akan dijelaskan suatu model manajemen risiko rantai pasok untuk mengoptimalkan pemilihan jadwal tanam pada komoditas jagung dengan pendekatan kualitatif dan kuantitatif. Model kuantitatif didekati dengan metode MILP (Mixed Integer Linear Programming), model kualitatif dengan AHP (Analytic Hierarchy Process) dan modelintegrasi dengan metode weighted sum. Hasil verifikasi dari pendekatan ini diperoleh nilai-nilai pareto yang dapat digunakan oleh pengambil keputusan untuk menentukan jadwal tanam yang optimal berdasarkan kriteria jamak dengan fungsi tujuan kualitatif dan kuantitatif."

"Growth and yield of plants are increased when plants are provided with mixtures of nitrate and ammonium compared with either form alone. Therefore, the objective of this experiment was determine the optimum of nitrate and ammonium ratio caused an increased in growth and yield of green pak choy (Brassica chinensis L.) The experiment was designed in Randomized Completely Design with five treatments of nitrate ammonium ratios and arranged in four replication. The treatments of nitrate ammonium ratio were : 100/0; 75/25; 50/50; 25/75 and 0/100. The results showed that nitrogen fertilizer applied in mixture nitrate and ammonium gave different effects in leaf nitrate reductase activity, leaf nitrogen content, growth and yield of green pak choy. There was significant correlation between the leaf nitrate reductase activity and leaf nitrogen content. There was also significant correlation between the leaf nitrate reductase activity with growth and yield of green pak choy. Nitrate ammonium ratio at 75/25 and 50/50 have better affect on the leaf nitrate reductase activity, leaf nitrogen content, growth and yield of green pak choy"

"The objective of this research is to investigate the effect of water deficit on the growth and yield of corn . The variety of corn used in this research was new and doesnt have market label. This research in conducted under plastic house on the experimental farm of Lampung University from August to October 2007..."

"Minyak kelapa sawit memiliki potensi yang tinggi untuk dikembangkan menjadi bio-oil oleh karena kandungan trigliserida. Indonesia merupakan negara produsen kelapa sawit terbesar di dunia. Selama ini minyak kelapa sawit belum dimanfaatkan secara maksimal khususnya sebagai bahan baku industri. Padahal minyak kelapa sawit dapat dimanfaatkan sebagai energi terbarukan melalui proses slow co-pyrolysis. Dalam penelitian ini, trigliserida yang digunakan dari minyak goreng kelapa sawit. Selain itu, limbah plastik juga berlimpah di Indonesia, terutama plastik polipropilena. Tujuan penelitian ini adalah untuk mengetahui pengaruh laju oenambahan plastik polipropilena terhadap yield dan kualitas bio-oil hasil slow co-pyrolysis minyak kelapa sawit. Penelitian ini dilakukan dalam reactor tabung berpengaduk pada suhu 550oC, heating rate 5oC/menit, kecepatan pengaduk 65 RPM dengan laju alir gas nitrogen 550 mL/min. Variasi yang dilakukan berupa penambahan jumlah % massa plastik polipropilena yang akan mempengaruhi yield dan komposisi dari bio-oil yang dihasilkan. Bio-oil dikarakterisasi dengan menggunakan GC-MS, dan FTIR. Efek sinergetik pada pirolisis PP-trigliserida tidak terjadi, sedangkan pada pirolisis PP-bonggol jagung terjadi saat komposisi PP 50% dan 75%. Bio-oil optimum dihasilkan pada komposisi PP 75% baik pada pirolisis PP-trigliserida dan PP-bonggol jagung.

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Palm oil has high potential to be developed into bio-oil because of the content of triglycerides. Indonesia is the largest palm oil producer in the world. So far, palm oil has not been fully utilized, especially as an industrial raw material. Even though palm oil can be used as renewable energy through the slow co-pyrolysis process. In this study, the the triglyceride is from palm oil cooking oil. In addition, plastic waste is also abundant in Indonesia, especially polypropylene plastic. The purpose of this study was to determine the effect of the rate of addition of polypropylene plastic on the yield and quality of bio-oil produced by slow co-pyrolysis of palm oil. This research was conducted in a stirred tube reactor at a temperature of 550oC, heating rate of 5oC / minute, stirrer speed of 65 RPM with a nitrogen gas flow rate of 550 mL / min. The variation is in the form of increasing the mass% of polypropylene plastic which will affect the yield and composition of the bio-oil produced. Bio-oil is characterized by using GC-MS, and FTIR. The synergetic effect on PP-triglyceride pyrolysis did not occur, whereas in the pyrolysis of PP-corn hump occurred when the composition of PP was 50% and 75%. Optimum Bio-oil was produced in the composition of PP 75% both in PP-triglyceride pyrolysis and PP-corncobs.

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"Penelitian bertujuan untuk mengetahui pengaruh pemberian pupuk NPK BASF dan pupuk pelengkap cair T-N-F pada berbagai taraf perlakuan yang di laksanakan di Kebun Percobaan Fakultas Pertanian Universitas Pembangunan Panca Budi Medan....."

"Salah satu metode pengerasan permukaan dengan jalan merubah komposisi kimia yaitu dengan proses cyaniding. Atom N (Nitrogen) diperoleh dari hasil reaksi garam KFe (CN)3 dengan oksigen/udara dengan aktivator Na2CO3. Atom N akan berdifusi masuk ke dalam permukaan sehingga permukaan akan diperoleh lapisan white keras Fe4N dan Fe2N yang sifatnya keras."

"Characterizations have been performed on single stage Transversely Excited Nitrogen Laser of Blumlein type. Optical cavity arrangement is varied prior to measurement which shows no significant increase in energy on both configurations of inserting a mirror only and a pair of mirror and a quartz parallel plate. Frequency repetitions respond reveals a small drop in energy at higher frequency i.e. 10 Hz by a factor of 20%. N2 flow rate consideration behaves on the similar way like pressure profile. At higher supply voltage maximum energy is shifted to higher N2 flow rate. A similar tendency occurs on pressure curve but with more pronounced maximum energy. Higher supply voltage would shift maximum energy to higher N2 pressure. Other operating conditions have been kept constant. Beam divergence measurement has given 1,87 mrad on vertical direction and 9,32 mrad on horizontal axis. However, beam cross section experiences a -10° tilt against horizontal reference. This may happen due to a slight twist on main electrodes. Measurements on different date have showed inconsistent results. Major cause is suspected on using different N2 cylinder, replacement on the gauge pressure, and crater creation on HV side spark gap electrode."