bluuebunny/crossref_metadata_2025 huggingface dataset:
Pembuatan bioetanol dari rumput gajah dengan distilasi batch
Authors: Sari Ni Ketut
Published: March 2020

Elephant grass is available continuously and in abundance, but has only been utilized as animal feed, and is sometimes regarded as a nuisance. However, elephant grass contains cellulose, glucose and starch that can be utilized as raw materials for ethanol production. The concentration of ethanol obtained from a study on the production of bioethanol from elephant grass was between 7-11%. To improve the purity of the ethanol, a batch distillation separation process was performed.  In the study of bioethanol production from elephant grass, a hydrolysis process was performed at the following fixed condition 30 oC temperature, 7 liter of water, 1 hour of hydrolysis time, while the following variables were changed fermentation period of 4, 5, 6, 7, and 8 days, and starter concentration of 8, 10, and 12%. From the bioethanol production study, the following best condition was obtained: 200 gram of grass, 10% Saccharomyces cerevisiae starter for 6 days. This condition produced 27.71% ethanol, with a 8.09% residual glucose. To obtain a higher purity ethanol product, a subsequent separation using batch distillation was performed, resulting in 90-95% ethanol. Therefore, elephant grass can be used as an alternative raw material for bioethanol production.Keywords: bioethanol, fermentation, hydrolysis, elephant grass Abstrak Ketersediaan rumput gajah dapat diperoleh secara kontinu dan melimpah, seringkali hanya digunakan sebagai makanan ternak, dan terkadang rumput gajah juga dianggap sebagai tanaman pengganggu. Rumput gajah mempunyai kadar selulosa, glukosa, pati yang dapat digunakan sebagai salah satu bahan penghasil etanol. Kadar etanol yang diperoleh dari kajian produksi bioetanol dari rumput gajah antara 7-11%. Untuk meningkatkan kemurnian kadar etanol dilakukan pemisahan menggunakan distilasi batch. Dalam penelitian kajian produksi bioetanol dari rumput gajah dilakukan proses hidrolisis pada kondisi tetap suhu 30 oC, air 7 liter, waktu hidrolisis 1 jam, dan kondisi berubah yaitu berat rumput gajah 50, 100, 150, 200, 250, dan 300 gram, volume larutan HCl 10, 20, 30, 40, 50 mL. Kemudian dilanjutkan proses fermentasi pada kondisi tetap suhu 30 oC, pH 4,5, volume fermentasi 500 mL dan kondisi berubah yaitu waktu fermentasi 4, 5, 6, 7, 8 hari, dan starter 8, 10, dan 12%. Dari penelitian kajian produksi bioetanol dari rumput gajah diperoleh hasil terbaik  yaitu: berat rumput gajah 200 gram, starter Saccharomyces cerevisiae 10% selama 6 hari, menghasilkan etanol sebesar 27,71% dan kadar glukosa sisa 8,09%. Untuk memperoleh produk etanol yang lebih murni dilakukan proses pemisahan lanjutan dengan distilasi batch, setelah dilakukan pemisahan lanjut diperoleh kadar etanol 90–95%, sehingga  rumput gajah dapat digunakan sebagai bahan baku alternatif pembuatan bioetanol.Kata Kunci: bioetanol, fermentasi, hidrolisis, rumput gajah.
Tinjauan karakteristik foam plastik mikroseluler polistirena dengan penambahan aditif pada teknologi superkritis
Authors: Minah Faidliyah Nilna , Kurniawansyah Firman , Sumarno S
Published: March 2020

Processing technology of microcellular plastic represents development of foaming conventional plastic process. The processing of microcellular plastic has been acknowledged as eco-friendly technology because this plastic is produced by the use of benign supercritical carbon dioxide gas as blowing agent. In this work, the samples polystyrene and additive were saturated with supercritical CO2 at various saturation pressures from 10-22 MPa (at around glass transition temperature of 95 oC and 80 oC) When the saturation time was accomplished, the solution was decompressed rapidly into atmospheric pressure. The samples were placed in the vessel heated and completed by flowing of carbon dioxide as cooler gas into the vessel. The samples were characterized to observe volume expansion ratio, cell density, average cell diameter and surface fractured with Scanning Electron Microscopy. The microcellular foam of plastic product of PS system has cell diameter between 3.970-9.933 μm , cell density between 9.14x104 – 6.24x109 cell/ cm3. PS-CaCO3 system has cell diameter between 3.501-8.050 μm, cell density between 3.31x107 – 1.10x1011 cell/cm3, while PS-coconut fiber system hascell diameter between 2.520-8.414 μm, cell density between 1.50x108 -1.60x1010 cell/cm3 at various pressure.Keywords: polystyrene, microcellular foam plastic, supercritical CO2, CaCO3additive, coconut fiber additive.  AbstrakProses pembuatan plastik mikroseluler merupakan pengembangan dari proses pembuatan foam plastik konvensional. Plastik mikroseluler menggunakan fluida superkritis seperti CO2 dan N2 sebagai blowing agent yang ramah terhadap lingkungan, sehingga proses pembuatan foam plastik mikroseluler dikenal sebagai teknologi ramah lingkungan. Penelitian ini menggunakan sampel polistirena yang dicampur dengan partikel kalsium karbonat atau sabut kelapa dengan konsentrasi 5% yang diproses pada kondisi tekanan 10-22 MPa (T = 95 oC dan 80 oC). Setelah kondisi yang diinginkan tercapai dilakukan dekompresi secara mendadak menuju tekanan atmosfer, dan dilanjutkan dengan proses pemanasan, diakhiri dengan mengalirkan gas CO2 sebagai pendingin. Selanjutnya sampel dikarakterisasi untuk mengetahui rasio volume ekspansi foam, densitas sel, diameter rata-rata sel dan struktur foam yang dihasilkan dengan Scanning Electron Microscope. Pada penelitian ini didapatkan pada sistem PS Murni menghasilkan diameter sel antara 3,970-9,933 μm dan densitas sel 9,14x104 - 6,24x109 cell/cm3. Sistem PS-CaCO3 menghasilkan diameter sel antara 3,501-8,050 μm dan densitas sel 3,31x107 - 1,10x1011 cell/cm3, dan pada sistem PS-Sabut kelapa menghasilkan diameter sel antara 2,520-8,414 μm dan densitas sel 1,50x108 - 1,60x1010 cell/cm3 pada berbagai variasi tekanan.Kata kunci : polistirena, foam plastik mikroseluler, CO2 superkritis, aditif CaCO3, aditif sabut kelapa.
Pengaruh konfigurasi liquid jet flow kolom gelembung terhadap kemampuan absorpsi gas karbondioksida
Authors: Setiadi S , Supramono Dijan , Istiqomah Nur
Published: March 2020

Efforts to improve the performance of CO2 absorption using bubbling columns and liquid jet flow have consistently been developed. The advantage of the present column is the presence of gas entrainment by suction of nozzle and the gas dispersed throughout the bulk of liquid by the formation of bubble clouds. The selection of liquid jet flow configuration used parameters of nozzle position and liquid jet inclination. The configurations have been examined by hydrodynamic test by measuring the ratio of volumetric rate of gas to that of liquid exiting nozzle (QG/QL) and gas holdup. Absorption test to the best configuration used NaOH solution with flowrate of 5 litres/min at atmospheric pressure and CO2 gas feed of 96.6%. The results showed that the configurations of liquid jet flow gave significant effect on hydrodynamics and that the best configurations had gas hold-up in the range of 0.55-0.6 and QG/QL 1.3-1.8. Absorption tests showed that CO2 concentration can be reduced into 0.01%-0.07% in less than five minutes and the absorption should proceed with the chemical reaction up to 10 minutes with no indication of CO2 desorption. The bubbles were generated in the column predominantly in the diameter range of 0.00097-0.00184 mm.Keywords: Configurations of liquid jet, bubble column, gas entrainment, CO2 gas absorption AbstrakUpaya meningkatkan kinerja absorpsi gas CO2 yang memanfaatkan kolom gelembung dan liquid jet flow telah banyak dilakukan. Keunggulan kolom gelembung dalam riset ini adalah kolom menyebabkan gas entrainment (pengisapan gas) dan dispersi gas ke dalam cairan yang membentuk awan gelembung. Pemilihan konfigurasi liquid jet flow terbaik berdasarkan posisi nosel dan arah sudut tembakannya dan dengan mengukur rasio laju volumetrik aliran gas entrainment terhadap laju volumetrik aliran cairan (QG/QL) serta gas hold-up untuk setiap konfigurasi. Konfigurasi terbaik digunakan untuk menentukan kinerja kolom gelembung untuk mendapatkan kinerja kemampuan absorpsi yang setinggi-tingginya. Uji absorpsi dilakukan terhadap konfigurasi terbaik dengan menggunakan absorben larutan NaOH dengan laju alir 5 L/min pada tekanan atmosferik dan umpan gas CO2 dengan kadar 96,6%. Hasil penelitian menunjukkan bahwa konfigurasi memberikan pengaruh cukup signifikan dan bahwa konfigurasi terbaik memberikan gas hold-up kisaran 0,55-0,65 dan rasio QG/QL bernilai 1,3-1,8. Uji absorpsi menunjukkan berkurangnya kadar CO2 menjadi 0,01% hingga 0,07% setelah absorpsi kurang dari 5 menit dan tetap tidak berubah sampai 10 menit. Hal ini menandakan bahwa absorpsi terjadi secara kimiawi antara gas CO2 dan NaOH and tidak terjadi desorpsi walaupun kolom gelembung tetap resirkulasi. Populasi gelembung menunjukkan distribusi ukuran gelembung lebih dominan pada rentang diameter antara 0,00097-0,00184 mm.Kata Kunci: Konfigurasi liquid jet, kolom gelembung, gas entrainment, absorpsi gas CO2
Pengaruh perbandingan berat padatan dan waktu reaksi terhadap gula pereduksi terbentuk pada hidrolisis bonggol pisang
Authors: Gusmarwani Sri Rahayu , Budi M Sri Prasetyo , Sediawan Wahyudi Budi , Hidayat Muslikhin
Published: March 2020

One of the promising biofuel is bioethanol which can be produced from agricultural waste cellulosic biomass such as banana plant waste. Production of banana rhizome waste in Indonesia is about 107.5 Mton annually. Banana rhizome contains 58.89% cellulose material that can be processed to produce bioethanol through biological and chemical processes. Sulfuric acid can be used in hydrolysis of cellulose material in banana plant waste to produce sugars, and Saccharomyces cereviseae can be used to convert  sugars into  bioethanol. This paper presents the result of studies on effects of solid ratio and time in hydrolysis of banana plant waste to produce sugars at 120 oC. One litre of water and 10 mL of sulfuric acid was mixed with various weight of banana plant waste then heated in an autoclave. The liquid samples were taken at various time and its sugar contents were analyzed by Lane and Eynon Methode. The  solid ratio was varied between 1:6.25, 1:5.88, 1:5.55, 1:5.25, 1:5, 1:4.75, 1:4.54, and 1:4.375 and the time was varied between 0 minute and 90 minutse with 10 minutes interval. The highest yield of glucose of 13.08 g/100 mL was achieved in 80 minutes and 1:5 of solid ratio.Keywords: Bioethanol, banana rhizome, hydrolysisAbstrakBioetanol adalah salah satu bentuk energi terbarukan yang menjanjikan. Sumber energi bioetanol dapat berasal dari limbah pertanian yang jarang dimanfaatkan seperti bonggol pisang. Produksi bonggol pisang di Indonesia mencapai 107,5 Mton per tahun. Selulosa yang terkandung dalam bonggol pisang mencapai 58,89% dapat diubah menjadi etanol melalui proses biologi dan kimia (biokimia). Untuk mengubah selulosa menjadi glukosa (gula) diperlukan proses hidrolisis dengan bantuan asam, misalnya asam sulfat (H2SO4), sedangkan untuk mengubah gula menjadi bioetanol dipergunakan ragi Saccharomyces cereviseae. Dalam makalah ini disampaikan pengaruh perbandingan berat padatan dan waktu hidrolisis terhadap glukosa yang terambil pada reaksi hidrolisis untuk mengubah selulosa pada bonggol pisang menjadi glukosa yang dilakukan pada suhu 120oC. Satu liter aquades dan 10 mL larutan asam sulfat pekat ditambahkan pada padatan dengan perbandingan (padatan:air) yang bervariasi dari 1:6,25, 1:5,88, 1:5,55, 1:5,25, 1:5, 1:4,75, 1:4,54, dan 1:4,375. Selanjutnya campuran dipanaskan dalam autoclave sampai suhu yang diinginkan tercapai (120 oC) dan dijaga konstan. Sampel diambil sebanyak 6 mL setiap 10 menit sampai waktu 90 menit tercapai. Analisis glukosa yang terbentuk dilakukan dengan metode Lane-Eynon. Hasil glukosa yang paling baik sebesar 13,08 g/100 mL didapatkan pada suhu 1200C dalam waktu 80 menit dengan perbandingan padatan:aquadest 1:5.Kata Kunci: Bioetanol, bonggol pisang, hidrolisis
Pembuatan karbohidrazida dari hidrazin dan asam sianurat
Authors: Putrawan I Dewa Gede Arsa , Ihsan Alfandra , Sofyan S
Published: March 2020

Hydrazine is commonly used as an oxygen scavenger in boiler feed water treatment. However, this compound is very flammable and is a carcinogenic substance. The industries in developed countries has studied the alternatives for hydrazine since long time ago and started to replace hydrazine. Carbohydrazide is known to be a good alternative for hydrazine. This research is aimed to understand the synthesis routes of carbohydrazide and to determine the best route as well as to develope a detail procedure of carbohydrazide preparation for local application. Literature study showed that carbohydrazide can be made by reacting hydrazine and cyanuric acid, phosgene, dimethyl carbonate or diphenyl carbonate. The synthesis path which is appropriate to be applied in Indonesia is that via cyanuric acid. From laboratory testing, a detail procedure for making carbohydrazide from hydrazine and cyanuric acid has been developed. In the range of experimental conditions studied, carbohydrazide with purity of 90-92% could be obtained with yield of 20-60%.Keywords: Carbohydrazide, cyanuric acid, hydrazine AbstrakHidrazin umumnya digunakan sebagai pengikat oksigen dalam pengolahan air umpan boiler. Akan tetapi, senyawa ini merupakan bahan kimia yang mudah terbakar dan bersifat karsinogenik. Industri-industri di negara maju sudah lama mengkaji alternatif pengganti hidrazin sebagai pengikat oksigen dan sudah mulai meninggalkan hidrazin. Senyawa yang diperkirakan potensial untuk menggantikan hidrazin adalah karbohidrazida. Tujuan  penelitian ini adalah untuk memahami rute sintesis karbohidrazida dan menentukan rute yang tepat serta menyusun langkah-langkah detil proses pembuatan karbohidrazida untuk penerapan lokal di tanah air. Studi literatur menunjukkan bahwa karbohidrazida dapat diperoleh dengan mereaksikan hidrazin hidrat dan asam sianurat, fosgen, dimetil karbonat atau difenil karbonat. Alur yang diperkirakan tepat untuk dikembangkan di Indonesia adalah alur melalui asam sianurat. Melalui uji coba di laboratorium, prosedur pembuatan karbohidrazida dari hidrazin dan asam sianurat yang detil telah disusun. Pada kondisi yang dikaji, karbohidrazida dengan kemurnian90-92% dapat disintesis dengan perolehan pada rentang 20-60%.Kata kunci: karbohidrazida, asam sianurat, hidrazin.
Kesetimbangan sorpsi ion seng(ii) pada partikel gambut
Authors: Munawar M
Published: March 2020

Extensive exposure of  zinc(II) ions  may cause eminent health problems, such as stomach cramps, skin irritations, vomiting, anaemia, a damage of pancreas, the disturbance of protein metabolism, and also respiratory disorders. Due to these problems, zinc(II) concentration in drinking water should be controlled. Peat is one of the material that can be used  to minimize zinc(II)  ions from  a solution. The study was done to determine the performance and sorption equilibrium of zinc ions onto oligothropic peat particles. The sorption experiments were conducted in a several batch reactor of erlenmeyer flask at a constant temperature of 26 ± 3 oC. The initial zinc ions concentration and pH were varied. Response variable was residual zinc concentration that was measured spectrophotometrically. Experimental data show that the optimum sorption efficiency was about 90% for the initial zinc(II) concentration of 50 mg/L. Sorption equilibrium can be represented by the Freundlich and Langmuir isotherm models. For the initial pH of 6, the optimum sorption capacity, qo was 3,736 mg/g, and the Freundlich’s characteristic  constant, Kf was about 0,342 L/g.    Key words : peat, sorption equilibrium, sorption isotherm, zinc(II) ions AbstrakPaparan ion seng(II) pada kadar tertentu dapat menyebabkan berbagai masalah kesehatan seperti kram perut, iritasi kulit, batuk, anemia, kerusakan pankreas, gangguan metabolisme protein, penyumbatan pembuluh darah, hingga kerusakan sistem pernafasan. Karena itu, seng(II) termasuk kategori unsur yang harus dibatasi konsentrasinya dalam air minum. Gambut adalah salah satu material yang dapat digunakan untuk mengurangi ion seng dari larutan. Penelitian ini bertujuan untuk mempelajari performansi dan kesetimbangan sorpsi ion seng(II) pada partikel gambut oligotropik Indonesia. Penelitian dilakukan secara batch di dalam sejumlah labu erlenmeyer pada temperatur konstan 26 ± 3 oC. Eksperimen dilakukan dalam beberapa variasi konsentrasi awal ion seng dan pH. Data primer adalah konsentrasi residual seng dalam larutan yang diukur secara spektrofotometrik. Hasil penelitian menunjukkan bahwa efisiensi optimum sorpsi mencapai lebih dari 90% untuk konsentrasi awal seng 50 mg/L. Kesetimbangan sorpsi logam seng(II) pada partikel gambut dapat direpresentasikan dengan baik oleh model isoterm Freundlich dan Langmuir. Untuk rentang pH awal 6, nilai kapasitas sorpsi optimum, qo adalah 3,736 mg/g, sedangkan nilai konstanta karakteristik Freundlich, Kf  adalah 0,342 L/g. Kata kunci : efisiensi sorpsi, gambut, isoterm sorpsi, ion seng(II)
Thermodynamic study on vapour-liquid equilibrium of toluene and several types of oil as absorbent
Authors: Hendriyana H , Suhartono S , Susanto Herri
Published: March 2020

Thermodynamic study on vapour-liquid equilibrium of toluene and several types of oil as absorbent Gas cleaning system is one of important step in the utilization of biomass via gasification process. The producer gas obtained from the gasification process must be very clean before it is used in an internal combustion engine. In order to gaseous fuel get cleaned with a tar content below 100 mg/Nm3, a gas cleaning system using scrubbing oil is being developed and taking the advantage of a lower vapour pressure of oil than scrubbing water. Study on vapour-liquid equilibrium is being conducted to understand the phenomena taking place in the absorption of tar with oil. In our present study, the producer gas containing tar is represented using air containing toluene. This producer gas model with a toluene or benzene concentration then bubbled with a rate of 27.6 mL/min into a bath of oil at a various temperature. The progress of absorption of tar model in oil measured gas chromatography until saturated condition. Considering that the concentration of toluene in the gas stream is very low, the toluene and oil vapour-liquid equilibrium follows the Henry’s law. Prediction of Henry’s constants is also carried out using UNIFAC-FV model which is known to be suitable for hydrocarbon gases and high-boiling point hydrocarbon solvent. Keywords: tar, oil, Henry’s constant AbstrakSistem pembersihan gas merupakan salah satu langkah penting dalam pemanfaatan biomassa melalui proses gasifikasi. Gas produser yang dihasilkan dari proses gasifikasi harus sangat bersih sebelum digunakan dalam mesin pembakaran internal. Untuk mendapatkan bahan bakar gas yang bersih dengan kandungan tar di bawah 100 mg/Nm3. Sebuah sistem pembersihan gas dengan menggunakan minyak sebagai media penyerap dikembangkan dengan mengambil keuntungan dari tekanan uap minyak lebih rendah air penyerap. Studi kesetimbangan uap-cair yang dilakukan untuk memahami fenomena yang terjadi dalam penyerapan tar dengan minyak. Dalam kami studi ini, gas produser yang mengandung direpresentasikan dengan udara yang mengandung toluena. Model gas produser ini dibuat dengan menggelembungkan konsentrasi benzena atau toluena dengan laju 27,6 mL/menit ke dalam bak minyak pada berbagai suhu. Kemajuan penyerapan model tar dalam minyak diukur dengan cromathograpy gas sampai dengan kondisi jenuh. Mengingat konsentrasi toluena dalam aliran gas sangat rendah, maka kesetimbangan uap-cair toluena dan minyak mengikuti hukum Henry. Konstanta Henry juga dapat diprediksi dengan menggunakan model UNIFAC-FV yang cocok untuk gas hidrokarbon dan pelarut hidrokarbon dengan titik didih tinggi. Kata kunci: tar, minyak, konstanta Henry
Pengaruh krom pada elektrodeposisi nikel dari larutan nikel-krom
Authors: Widiatmoko Pramujo , Nurdin Isdiriayani
Published: March 2020

The chromium effect on nickel electrodeposition from nickel-chromium solution Electrodeposition, which can convert nickel ion into pure nickel metal, is an alternative for reducing nickel concentration in electroplating waste and in same time increasing its economic value. The aim of this research is to study the effect of chromium presence on the performance of Nickel recovery from liquid waste of Ni-Cr electroplating process. Liquid of electroplating waste leachate is represented by solutions containing nickel and chromium sulfate method. All experiments were carried out at ambient temperature and pressure with Cr/Ni ratio and boric acid composition as variables. Result of the research shows that chromium presence in solution with 28.9% Cr/Ni ratio increases activation polarization of about 500 mV. Optimum condition of the experiment is obtained for Cr/Ni ratio 3.7%-w. Increasing Cr/Ni ratio from 3.7% to 14.8% decreases current efficiency by 57% and deposition efficiency by 5%, and also increases energy consumption by 8.3%. Morphology of deposited nickel deteriorates with increasing of Cr/Ni ratio and hydroxide compound is formed when it reaches 14.8%. Keywords: nickel electrodeposition, nickel-chromium solution, chromium, electroplating wasteAbstrakElektrodeposisi merupakan metode alternatif yang potensial untuk mengurangi kandungan nikel dari limbah elektroplating sekaligus meningkatkan nilai ekonomisnya, dengan produk berupa logam nikel murni. Penelitian ini bertujuan mengkuantifikasi pengaruh krom dalam proses pemulihan nikel dari larutan limbah industri yang mengandung nikel dan krom. Nikel sulfat dan krom sulfat digunakan sebagai pendekatan larutan hasil ekstraksi limbah padat. Percobaan dilakukan pada tekanan dan temperatur ruang dengan variasi rasio krom terhadap nikel serta konsentrasi asam borat sebagai aditif. Hasil percobaan menunjukkan bahwa keberadaan krom dengan rasio Cr/Ni 28,9% meningkatkan polarisasi aktivasi sekitar 500 mV. Kondisi optimum untuk percobaan ini diperoleh ketika rasio Cr/Ni 3,7%-berat. Perubahan rasio Cr/Ni dalam larutan dari 3,7% menjadi 14,8% menurunkan efisiensi arus sebesar 57%, menurunkan efisiensi deposisi 5%, serta meningkatkan kebutuhan energi hingga 8,3%. Morfologi deposit nikel menjadi lebih buruk dengan kenaikan rasio Cr/Ni, dan berubah menjadi deposit hidroksida pada rasio Cr/Ni 14,8%.Kata kunci: elektrodeposisi nikel, larutan nikel-krom, krom, limbah elektroplating
Minimum miscibility pressure computation in eor by flare gas flooding
Authors: Samadhi Tjokorde Walmiki , Siagian Utjok W.R. , Budiono Angga P
Published: March 2020

The technical feasibility of using flare gas in the miscible gas flooding enhanced oil recovery (MGF-EOR) is evaluated by comparing the minimum miscibility pressure (MMP) obtained using flare gas to the MMP obtained in the conventional CO2 flooding. The MMP is estimated by the multiple mixing cell calculation method with the Peng-Robinson equation of state using a binary nC5H12-nC16H34 mixture at a 43%:57% molar ratio as a model oil. At a temperature of 323.15 K, the MMP in CO2 injection is estimated at 9.78 MPa. The MMP obtained when a flare gas consisting of CH4 and C2H6 at a molar ratio of 91%:9% is used as the injection gas is predicted to be 3.66 times higher than the CO2 injection case. The complete gas-oil miscibility in CO2 injection occurs via the vaporizing gas drive mechanism, while flare gas injection shifts the miscibility development mechanism to the combined vaporizing / condensing gas drive. Impact of variations in the composition of the flare gas on MMP needs to be further explored to confirm the feasibility of flare gas injection in MGF-EOR processes. Keywords: flare gas, MMP, miscible gas flooding, EORAbstrakKonsep penggunaan flare gas untuk proses enhanced oil recovery dengan injeksi gas terlarut (miscible gas flooding enhanced oil recovery atau MGF-EOR) digagaskan untuk mengurangi emisi gas rumah kaca dari fasilitas produksi migas, dengan sekaligus meningkatkan produksi minyak. Kelayakan teknis injeksi flare gas dievaluasi dengan memperbandingkan tekanan pelarutan minimum (minimum miscibility pressure atau MMP) untuk injeksi flare gas dengan MMP pada proses MGF-EOR konvensional menggunakan injeksi CO2. MMP diperkirakan melalui komputasi dengan metode sel pencampur majemuk dengan persamaan keadaan Peng-Robinson, pada campuran biner nC5H12-nC16H34 dengan nisbah molar 43%:57% sebagai model minyak. Pada temperatur 323.15 K, estimasi MMP yang diperoleh dengan injeksi CO2 adalah 9.78 MPa. Nilai MMP yang diperkirakan pada injeksi flare gas yang berupa campuran CH4-C2H6 pada nisbah molar 91%:9% sangat tinggi, yakni sebesar 3.66 kali nilai yang diperoleh pada kasus injeksi CO2. Pelarutan sempurna gas-minyak dalam injeksi CO2 terbentuk melalui mekanisme dorongan gas menguap (vaporizing gas drive), sementara pelarutan pada injeksi flare gas terbentuk melaui mekanisme kombinasi dorongan gas menguap dan mengembun (vaporizing/condensing gas drive). Pengaruh variasi komposisi flare gas terhadap MMP perlu dikaji lebih lanjut untuk menjajaki kelayakan injeksi flare gas dalam proses MGF-EOR.Kata kunci: flare gas, MMP, miscible gas flooding, EOR
Pemodelan perpindahan massa ekstraksi kolom isian dengan distribusi ukuran tetesan
Authors: Ridwan Iwan
Published: March 2020

Mass transfer modeling of extraction in a packed bed with droplet size distribution The evaluation of liquid extraction packed column is not able yet to give a satisfying result caused by constant spherical droplet size assumption. Droplet size from dispersion phase that is not homogeneous causes column calculation approach with assumption form of droplet haves the character of constant cannot be applied again. The goal of this research is to build droplet distribution model and mass transfer model at various heights of extraction column both in continuous phase and in dispersion phase. Droplet distribution model is more accurately applied to describe droplet breaks distribution for extraction in glass ball packed column with average of errors 4.53% compared to raschig ring packed column with average error of 11.52 %. At glass ball packing, the mass transfer modeling with total droplet has errors average to 57.67% while at raschig ring packing the model has errors average to 121.38%. Glass ball packing column model has smaller mean errors compared to raschig ring packing column because the glass ball packing form is more regular than the raschig ring packing. The amount of error between the mass transfer models and the experiment is caused by difference of the initial number of droplets that exit from the nozzle in the half circle column and in the full circle column. Keyword: extraction, packed column, droplet distribution model, mass transfer model AbstrakUkuran tetesan dari fasa dispersi yang tidak homogen menyebabkan pendekatan perhitungan kolom dengan asumsi bentuk tetesan bersifat konstan tidak dapat digunakan lagi. Tujuan dari penelitian ini adalah untuk membangun model distribusi tetesan dan model perpindahan massa pada berbagai ketinggian kolom ekstraksi baik di fasa kontinu maupun di fasa dispersi. Model distribusi tetesan lebih tepat digunakan untuk memodelkan fraksi tetesan pecah hasil penelitian pada ekstraksi kolom isian bola kaca dengan rata-rata error sebesar 4,53% dibandingkan dengan kolom isian raschig ring yang mempunyai error sebesar 11,52 Pada isian bola kaca pemodelan perpindahan massa dengan tetesan total mempunyai error rata-rata sebesar 57,67% sedangkan pada isian raschig ring mempunyai error rata-rata sebesar 121,38%. Model kolom isian bola kaca mempunyai error rata-rata yang lebih kecil dibandingkan dengan kolom kolom isian raschig ring, dikarenakan model isian bola kaca bentuknya lebih beraturan dibanding dengan kolom isian raschig ring yang bentuknya lebih tidak beraturan. Besarnya error perpindahan massa antara model dengan percobaan disebabkan oleh tidak samanya jumlah tetesan awal pada kolom setengah lingkaran dengan jumlah tetesan awal pada kolom lingkaran penuh.Kata kunci : ekstraksi,kolom isian, model distribusi tetesan, model perpindahan massa
Simulation and optimization of coupling reaction of methanol synthesis and isopropyl alcohol dehydrogenation
Authors: Rizkiana Jenny , Budhi Yogi Wibisono , Trianto Azis
Published: March 2020

A study on simulation and optimization of coupling reaction between methanol synthesis and isopropyl alcohol (IPA) dehydrogenation was performed. The analysis is carried out theoretically to obtain the optimum operation conditions which give the best performance. The reactions are just interacting thermally. In this study, both reactions are held catalytically in a heat-exchanger type reactor. As a high pressure reaction, methanol synthesis is placed in the inner side of reactor tube while dehydrogenation of IPA is in the opposite. Tube wall acts as a heat transfer media. The reactor is modeled by a steady state heterogeneous equation for a fixed bed reactor. Optimization is done in order to find the optimum value of operation conditions, those are the inlet temperature of both side of reactor and the molar feed flow ratio between the exothermic side and the endothermic side. Sum of weighted reaction conversion is considered to be the objective function that is maximized. The simulation result shows that coupled reactor makes the reaction conversion higher than a conventional adiabatic reactor and the optimum operation conditions give the maximum value of the conversion. This study presents a theoretical proof that coupling reaction is feasible. Keywords: coupling reaction, IPA dehydrogenation, methanol synthesis, optimization, simulated annealingAbstrak Telaah mengenai simulasi dan optimisasi reaksi perangkaian (coupling reaction) antara sintesis metanol dengan dehidrogenasi isopropil alkohol (IPA) telah dilakukan. Analisis dilaksanakan secara teoretik guna mendapatkan kondisi optimum yang akan memberikan hasil terbaik. Pada penelitian ini, kedua reaksi dilaksanakan secara katalitik dalam reaktor bertipe buluh-cangkang. Karena bertekanan tinggi, sintesis metanol ditempatkan pada sisi buluh, sedangkan dehidrogenasi IPA ditempatkan pada sisi cangkang. Dinding buluh berperan sebagai media perpindahan panas. Reaktor dimodelkan dengan reaktor heterogen tunak unggun tetap. Optimisasi dilakukan dalam rangka mendapatkan nilai optimum dari kondisi operasi yang mencakup temperatur inlet sisi eksotermik dan endotermik serta rasio umpan molarnya. Jumlah total konversi reaksi terbobotkan dipilih sebagai nilai objectif yang akan dioptimumkan. Hasil simulasi menunjukkan bahwa reaktor perangkaian termal mampu meningkatkan konversi reaksi jika dibandingkan dengan reaktor adiabatik dan pada kondisi operasi yang optimum diperoleh konversi maksimal. Penelitian ini menunjukkan bahwa reaksi perangkaian layak untuk dilaksanakan.Kata kunci: reaksi perangkaian, dehidrogenasi IPA, sintesis methanol, optimisasi, simulated annealing
Kinerja bioreaktor hibrid anaerob bermedia tandan dan pelepah sawit dalam penyisihan cod
Authors: Ahmad Adrianto , Amraini Said Zul , Luturkey Yance Andre
Published: March 2020

Performance of anaerobic hybrid bunch-frond palm mediated bioreactor in COD elimination The high contents of Chemical Oxygen Demand (COD) in palm oil mill wastewater is able to cause the obstructed connection between air and a receiver of water body so that can make the lessening oxygen solubility in the receiver of water body. Hence, it is important to do innovation to get a good technology process of wastewater in order that the contents of COD become low. One of the wastewater processes can be done by using hybrid anaerobic bioreactor in eliminating COD that exists in palm oil mill wastewater. This research uses two units of hybrid anaerobic bioreactor i.e. hybrid anaerobic bioreactor mediated immobilization cell of empty stem palm and hybrid anaerobic bioreactor mediated immobilization cell of in 2.5 m3 of work volume. The process is done by using variation of imposition organic rate i.e. 10, 12.5, 14.28, 16.6, 20, 25, 33.3, and 50 kg COD/m3-day. The result of research showed that the highest eliminating COD is 82.67% in 14.28 kg COD/m3-day in bioreactor filled with empty palm fruit bunch and 84% for imposition organic rate 16.6 kg COD/m3-day in bioreactor filled with palm midrib. Therefore, both hybrid anaerobic bioreactors can be used for processing oil palm mill wastewater in high load of COD. Keywords: hybrid bioreactor, COD, wastewater, palm midrib, empty stem palmAbstrakKandungan Chemical Oxygen Demand (COD) yang tinggi dalam limbah cair pabrik minyak sawit dapat menyebabkan terhambatnya kontak antara udara dengan badan air penerima sehingga mengakibatkan berkurangnya kelarutan oksigen dalam badan air penerima tersebut. Oleh karena itu, penting dilakukan terobosan baru untuk mendapatkan teknologi pengolahan limbah cair yang handal agar kandungan COD menjadi rendah. Salah satu teknologi pengolahan limbah cair tersebut adalah bioreaktor hibrid anaerob. Penelitian ini bertujuan mengkaji kinerja beberapa jenis bioreaktor hibrid anaerob dalam penyisihan COD dalam limbah cair pabrik minyak sawit. Pada penelitian ini digunakan dua unit bioreaktor yakni bioreaktor hibrid anaerob dengan media imobilisasi sel tandan kosong sawit dan bioreaktor hibrid anaerob dengan media imobilisasi sel pelepah sawit dengan volume kerja 2,5 m3. Proses pengolahan dilakukan dengan variasi laju pembebanan zat organik, yaitu10; 12,5; 14,28; 16,6; 20; 25; 33,3; 50 kg COD/m3hari. Hasil penelitian menunjukkan bahwa penyisihan COD yang tertinggi dicapai sebesar 82,67% dengan laju pembebanan organik 14,28 kg COD/m3hari pada bioreaktor bermedia tandan kosong sawit dan 84% untuk laju pembebanan organik 16,6 kg COD/ m3hari pada bioreaktor bermedia pelepah sawit. Dengan demikian, kedua bioreaktor hibrid anaerob ini dapat digunakan untuk mengolah limbah cair industri minyak sawit dengan beban COD tinggi.Kata kunci: bioreaktor hibrid, COD, limbah cair, pelepah sawit, tandan kosong sawit
A Quantitative Index to Rank and Select Electromagnetic Shields in Radiofrequency and Microwave Radiation
Authors: Zaroushani Vida , Khajehnasiri Farahnaz
Published: March 2020

Background: In electromagnetic shielding topics, the selection of suitable shields is an important subject and the lack of a specific ranking index for choosing protective shields causes problems in decision-making. Thus, this study proposes a quantitative index to rank and select electromagnetic shields in radiofrequency and microwave radiation. Objectives: The objective of this study was to construct a simple quantitative index to rank and select electromagnetic shields in radiofrequency and microwave radiation. Methods: A cross-sectional study was designed. In this study, the construction of the ranking index was carried out in four main stages including stabilizing the concept, analytical structure and variable selection, weighing and combination of variables, and validating the index. In this study, the average, minimum, maximum, and standard deviation of shielding effectiveness were considered the main phenomenon variables. Finally, the ranking index and ranking difference index were created as percentages to rank and select electromagnetic shields. Results: In this study, a quantitative index was made as percentages called "Ranking Index" to rank and select the premier and preferable shield. Moreover, to indicate the difference in the shielding effectiveness of various shields, the "Difference Index" was made as percentages. Conclusions: This study presented a simple quantitative index to rank electromagnetic shields. It could be used as a selection tool in radiation safety management. Moreover, this ranking index had a simple formula that could be calculated easily and quickly in excel software with high accuracy and low cost. In addition, it could be easily incorporated into a user-friendly tool for the ease of application. A case study of electromagnetic nanocomposite shields was conducted to use the Ranking Index, which showed its capability for ranking the shielding performance of studied electromagnetic shields. This index can create similar scientific literature to report the efficacy of electromagnetic shields and the selection of preferred shields in different research studies. It is suggested that future studies examine this quantitative index in other frequency ranges.
Autopoietic Systems
Authors: Paquette Elisabeth ,   Philosophy Documentation Center
Published: March 2020

In Autopoiesis and Cognition (1980), Humberto R. Maturana and Franscico J. Varela state that “the way an autopoietic system maintains its identity depends on its particular way of being autopoietic, that is, on its particular structure, different classes of autopoietic systems have different classes of ontogenies” (98). With this in mind, in this article I develop how this conception of autopoietic systems is both present in, and operates through, Wynter’s employment of space and place, poetry, and wonder.
Structure of the breeding bird community along the urban gradient in a town on the Zambezi River, north-eastern Namibia
Authors: Kopij Grzegorz
Published: March 2020

A simplified mapping method was employed to quantify avian assemblages in three study plots in a modified riparian forest on the Zambezi River in the town of Katima Mulilo, NE Namibia. The plots were arranged along the urbanization gradient: plot A (34 ha; 0–1 km from centre of the town), plot B (27 ha; 1–2 km from the centre), and plot C (24 ha; 2–3 km from the centre; periphery). In total, 51 breeding bird species were recorded in all three plots. Five of them, Columba livia domestica, Passer diffusus, Pycnonotus tricolor, Streptopelia senegalensis, and Uraeginthus angolensis were classified as dominant species. The cumulative dominance was 69.9%. The overall population density of all breeding species increased with the urban gradient. In general, granivorous birds were by far the most numerous feeding guild comprising 68.7% of all breeding birds. Two other guilds, frugivorous and insectivorous birds, together comprised 28.9%. While the proportion of granivores decreased along the urban gradient from the town centre to its periphery, the proportion of insectivores increased. The proportion of birds nesting in/on buildings decreased, and the share of tree/shrub- and hole-nesting birds increased along the urban gradient. The diversity indices were relatively high in all plots. They decreased only slightly along the urban gradient (from the centre to the periphery). However, the Pielou’s Evenness Index was comparatively low, but on a slight increase along the urbanization gradient. The Sorensen Similarity Index was low, but the values of the three studied plots were very similar.
The first record of the Siberian northern shrike (Lanius borealis sibiricus) in Lithuania with molecular confirmation
Authors: Eigirdas Vytautas , Jonikė Vesta
Published: March 2020

Climate change significantly affects biological diversity around the world. Trends of this phenomenon have also been noticed in Lithuania: in the past decades, 55 new bird species have been recorded. The recent record of a new species was done on 3 December 2019. During ordinary birds ringing carried out in Ventės Ragas Ornithological Station in Lithuania, an individual Siberian northern shrike (Lanius borealis sibiricus) was caught and ringed. Additional blood sample was collected for species confirmation. Based on identification keys and molecular mitochondrial cytochrome b analysis, we report that this is the first record of the Siberian northern shrike in Lithuania.
Amorphous state stability of plant vitrification solutions
Authors: Vozovyk Krystyna , Bobrova Olena , Prystalov Anton , Shevchenko Nadiya , Kuleshova Larisa
Published: March 2020

Two critical factors for obtaining high viable biological samples after cryopreservation by vitrification method are cryoprotectant glass-forming ability while cooling and the stability of its amorphous state during warming. The present work is devoted to the study of the amorphous state stability of plant vitrification solutions (PVS) by differential scanning calorimetry method. The objects of the study were PVS1 modified, PVS2, PVS3 modified, PVS4 and PVSN. The thermograms of PVSs, frozen in liquid nitrogen, were recorded at a warming rate of 0.5 deg/min. The glass transition temperatures of PVS1, PVS2 and PVS3 were –109.0°C, –115.3°C, and –93.9°C, respectively. Neither exo- nor endothermic peaks have been recorded, indicating no crystallization, at the cooling and the warming stages. PVS4 and PVSN thermograms, besides glass transition (–111.5°C and –110.0°C, correspondingly), showed crystallization from the amorphous state (devitrification) and ice melting peaks. Crystallization enthalpy of PVSN was 2.8 times higher compared to PVS4. This fact testifies that the crystalline phase was larger in PVSN compared to PVS4. It should be noted that crystallization in PVS4 and PVSN may be related to the low warming rate used during the experiment. At higher warming rates, this crystallization is likely to be avoided. Thus, PVS1, PVS2 and PVS3 have a high glass-forming ability and a stabile amorphous state. The amorphous state stability of PVS4 and PVSN is significantly lower compared to PVS1, PVS2, and PVS3.
Evaluation of different methods for preventing the African swine fever virus
Authors: Pilevičienė Simona , Jurgelevičius Vaclovas , Janeliūnas Žygimantas , Pridotkas Gediminas , Mačiulskis Petras , Krikštolaitis Ričardas , Paulauskas Algimantas
Published: March 2020

African swine fever (ASF) is a contagious disease of key importance that occurs in wild boar population and domestic pigs. To date, there is no vaccine or treatment available, hence disease surveillance and stamping out in case of an outbreak is the only way to control it. A duplex ASF-IC real-time PCR assay was optimised using field samples obtained in Lithuania and results of singleplex and duplex real-time PCR assays allowing the identification of the ASF virus were compared. The specificity and sensitivity of ASF virus detection was validated using a reference sample of positive and negative virus nucleic acid and ASF virus positive and negative samples obtained from animals in Lithuania. Results prove that duplex ASF-IC real-time PCR assay provides a rapid, sensitive, and reliable molecular tool for ASF virus detection in wild boar population and domestic pigs. In general, it was found that duplex ASF-IC real-time PCR assay proves to be faster and more sensitive than singleplex real-time PCR and therefore has a high potential to be applied in routine analysis.
Técnicas estatísticas para análise da qualidade da água em áreas irrigadas no baixo Rio São Francisco
Authors: Britto Fábio Brandão , Vasco Anderson Nascimento do , Morais Gilsia Fabiane Oliveira , Aguiar Netto Antenor de Oliveira
Published: March 2020

Conhecer os impactos da agricultura irrigada na qualidade da água é muito importante quando se busca construir estratégias de gestão para revitalizar mananciais. O objetivo do estudo foi realizar o monitoramento físico-químico e analisar os possíveis impactos da agricultura irrigada na qualidade da água no baixo rio São Francisco, nos municípios Canindé do São Francisco (semiárido) e Neópolis (semiúmido) no de período de 03/2013 a 12/2014. Foram monitorados mensalmente vinte e dois parâmetros físico-químicos em quatros mananciais: rio da Onça, rio Betume, drenagem Betume e rio São Francisco. Os dados obtidos foram analisados utilizando-se técnicas estáticas multivariadas para determinar suas inter-relações, como também, simplificar sua interpretação. Os parâmetros da qualidade da água estão relacionados principalmente com o conteúdo mineral, nutricional, matéria orgânica e grau de poluição. Dentre as regiões estudadas, o perímetro irrigado Califórnia apresentou um maior grau de eutrofização explicado principalmente pelos elevados valores de oxigênio dissolvido (OD), fósforo, nitrogênio e demanda bioquímica de oxigênio (DBO). O uso de técnicas estatísticos para analisar os resultados dos parâmetros físico-químicos, pode evidenciar os diversos problemas existentes nos perímetros irrigados no baixo rio São Francisco quanto ao manejo agrícola e a qualidade da água dos mananciais.
Resíduos sólidos orgânicos domésticos como substrato potencial para produção de biogás
Authors: Silva Claudionor de Oliveira , Konrad Odorico , Callado Nélia Henriques , Marder Munique , Araujo Liz Geise Santos de
Published: March 2020

O processo de digestão anaeróbia é uma alternativa de tratamento de materiais orgânicos e produção de energia renovável. A qualidade do biogás é dependente do tipo de substrato inoculado em reatores anaeróbios. Resíduos sólidos orgânicos domésticos apresentam quantidade de matéria orgânica volátil satisfatória para a produção de biogás. Foram identificados junto às empresas de coleta, os roteiros dos caminhões que fazem a coleta de lixo em Maceió. Selecionados os bairros e os caminhões que fazem o roteiro e a coleta de resíduos destes bairros, foi dado início ao levantamento de dados de gravimetria no aterro sanitário.  Identificar o potencial de produção de biogás deste resíduo é necessário para buscar outra logística de destinação e reduzir a disposição em aterro sanitário. Neste sentido, o presente estudo teve como objetivo avaliar o potencial bioquímico de biogás (PBB) e metano (PBM) dos resíduos sólidos orgânicos de origem doméstica (resíduos novos-RN), proveniente do aterro sanitário de Maceió, Alagoas. O ensaio de digestão anaeróbia foi realizado no Sistema Automatizado de Medição de Biogás (SAMB) no Centro de Pesquisa em Energia e Tecnologias Sustentáveis – CPETS/TECNOVATES - Univates/RS. O teste de PBB e PBM foi realizado pelo método padrão de fermentação, descrito na normativa alemã VDI 4630. Foram inoculadas uma triplicata de inóculo como branco (IN), uma triplicata com celulose microcristalina como amostra padrão (CM) e a triplicata com o resíduo sólido orgânico doméstico como substrato (RSOD). A qualidade do biogás foi avaliada por sensor específico de medição de metano e por cromatografia gasosa. O resultado do ensaio de digestão anaeróbia mostra que o RSOD apresenta PBB de 817,70 ± 13,43 m³. tonSV-1 com alto teor de metano (percentual máximo de metano de 75,15 %). Além disso, o período incubação do substrato foi de 17 dias, isso mostra a facilidade dos microrganismos assimilarem este substrato. Considerando os resultados obtidos, destaca-se que o RSOD apresenta potencial energético para uso como substrato em biodigestores anaeróbios.
Chemical and enzymatic transformations of progesterone in simulation water treatment processes at laboratory scale
Authors: Alves Thiago Caique , Dalke Karina Reinicke , Pinheiro Adilson
Published: March 2020

The removal of endocrine disrupting compounds (EDCs) present in waters and effluents has been proposed both by physical, chemical, and biological treatment methods and by the use of enzymes produced by living beings. While some methods prove efficient, it is known that steroid transformation can generate by-products with similar or increased disruptive capacity over the parent compounds. This study aimed to evaluate the removal of the progesterone molecule in oxidizing and enzymatic media and. to verify the formation of by-products. The samples were evaluated under different conditions when submitted to oxidizing media (pH, time, temperature, salinity) and enzyme medium (pH, time, enzymatic concentration). From the analyses, it was verified that the samples submitted to the oxidizing media presented lower average removal (18.7%) than the samples submitted to enzyme laccase (36.7%). Among the samples submitted to the oxidizing media, the positive influence of hydrogen peroxide on the average removal of progesterone (20.8%) was observed. While for the samples submitted to the enzymatic medium progesterone removal favored (43.9%) occurred in buffer solution pH 5 and the most extended incubation period (300 min). The generation of degradation byproducts was observed in the samples submitted to oxidizing media (12 by-products) and in the samples submitted to the enzymatic medium (a by-product). Thus, it is concluded that enzymatic media are more effective than oxidizing means in the removal of progesterone and that the generation of byproducts from progesterone occurs along with the exposure to both media.