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All Journal Jurnal Rekayasa Proses Jurnal Manajemen Teknologi Jurnal Teknik ITS IPTEK The Journal for Technology and Science Jurnal Sains dan Teknologi Journal of Engineering and Technological Sciences International Research Journal of Business Studies (E-Journal) Jurnal Teknik Industri: Jurnal Keilmuan dan Aplikasi Teknik Industri Indonesian Journal of Chemistry Jurnal Rekayasa Proses International Journal of Marine Engineering Innovation and Research Jurnal Teknik Kimia Indonesia Journal of Marine-Earth Science and Technology Makara Journal of Science Makara Journal of Technology Sewagati Jurnal Teknik Kimia dan Lingkungan Jurnal Teknologi Kimia Mineral Bulletin of Chemical Reaction Engineering & Catalysis International Research Journal of Business Studies Jurnal Rekayasa Proses

Sjarief Widjaja

Chemical Engineering Department, Institut Teknologi Sepuluh Nopember, Kampus ITS Sukolilo, Surabaya 6011

Author-ID : 415856

Arts Humanities Automotive Engineering Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Environmental Science Industrial & Manufacturing Engineering Languange, Linguistic, Communication & Media Materials Science & Nanotechnology Mechanical Engineering Physics Public Health Social Sciences Transportation Other

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Pra Desain Pabrik Hexamethylene Tetramine dari Formaldehid dan Ammonia Menggunakan Proses Meissner dengan Kapasitas Produksi 7000 Ton Nurul Maziyah; Laila Nur Rahmah; Arief Widjaja
Jurnal Teknik ITS Vol 5, No 2 (2016)
Publisher : Direktorat Riset dan Pengabdian Masyarakat (DRPM), ITS

Hexamethylene Tetramine (HMTA) atau yang lebih dikenal dengan hexamine memiliki penggunaan yang luas di bidang industri kimia yaitu sebagai akselerator pada industri karet, campuran TNT pada industri bahan peledak, shrink-proofing agent untuk memperindah warna pada industri tekstil, bahan pelapis butiran pupuk urea, inhibitor korosi, curing agent pada industri resin, bahan baku antiseptik, serta industri serat selulosa. Selain itu, dalam jumlah rendah, hexamine juga digunakan pada sintesis glycine maupun sebagai stabilizer pada polyvinyl acetate dan pelarut pada ekstraksi fenol. Indonesia sendiri hanya memiliki dua industri untuk memproduksi hexamine dan belum cukup untuk memenuhi kebutuhan sehingga Indonesia masih harus impor. Padahal kebutuhan hexamine terus meningkat dari tahun ketahun. Menurut BPS (2004 - 2011), impor hexamine Indonesia pada tahun 2011 mencapai 13.227.201 kg. Melihat banyaknya kegunaan hexamine dalam berbagai bidang dan perkembangan industri di Indonesia yang memanfaatkan produk ini sebagai bahan baku, maka pendirian pabrik ini sangat dibutuhkan. Pabrik Hexamethylene Tetramine direncanakan berdiri pada tahun 2019 yang berlokasi di Palembang, Sumatera Selatan dengan kapasitas produksi sebesar 7000 ton/tahun. Proses yang digunakan pada perencanaan Pabrik Hexamethylene Tetramine ini adalah menggunakan proses Meissner. Proses pembuatan hexamine dengan proses ini dapat dibagi dalam beberapa tahap, antara lain tahap persiapan bahan baku yakni ammonia dan formaldehid, tahap pembentukan hexamine di dalam reaktor yang selanjutnya diproses lebih lanjut untuk memisahkan kristal hexamine yang telah terbentuk, dan tahap pemurnian dan penyimpanan produk. Pabrik Hexamethylene Tetramine ini direncanakan beroperasi secara kontinyu selama 24 jam dengan waktu produksi 330 hari/tahun. Berdasarkan analisa ekonomi yang telah dilakukan diperoleh internal rate of return sebesar 19,05 % dengan pay out time selama 4,9 tahun dan break even point sebesar 40%. Ditinjau dari uraian di atas, maka secara teknis dan ekonomis, pabrik Hexamethylene Tetramine dari ammonia dan formaldehid layak untuk didirikan. Kata Kunci—Hexamethylene Tetramine, ammonia, formaldehid, Meissner

Reducing Sugar Production in Subcritical Water and Enzymatic Hydrolysis Using Plackett-Burman Design and Response Surface Methodology Maktum Muharja; Irfan Albana; Jayyid Zuhdan; Agra Bachtiar; Arief Widjaja
Jurnal Teknik ITS Vol 8, No 2 (2019)
Publisher : Direktorat Riset dan Pengabdian Masyarakat (DRPM), ITS

Subcritical water is one method of hydrolysis that can convert coconut husk to produce reducing sugars. However, this method has the disadvantage of producing derivative products such as furfural and phenolic compounds that act as inhibitors. One effective method is the addition of additives to the subcritical water process. The purpose of this study was to determine the effect of adding additives to subcritical water processes and optimizing the operating conditions on the production of reducing sugars. The analysis of reducing sugar was conducted by the dinitrosalicylic acid (DNS) method. Variables used in this study were time, temperature, pressure, water volume, pH, and several types of additives. Plackett-Burman was used for screening significant factors for the production of reducing sugars. The three most affecting factors were further investigated to find out the optimum point using Response Surface Methodology (RSM). The optimum point for subcritical water pretreatment operating conditions was the addition of sodium dodecyl sulfate (SDS) of 0.24 grams, reaction time for 80 minutes, and pH 11 yielding a reducing sugar yield of 22.7%, energy use of 291.3 kJ/g with desirability of 85%. Furfural content of all liquids after pretreatment can be neglected (<2 ppm) because of the effect of surfactant.

Comparative Study of the Preparation of Reducing Sugars Hydrolyzed from High-Lignin Lignocellulose Pretreated with Ionic Liquid, Alkaline Solution and Their Combination Hanny F. Sangian; Junaidy Kristian; Sukma Rahma; Silvya Yusnica Agnesty; Setiyo Gunawan; Arief Widjaja
Journal of Engineering and Technological Sciences Vol. 47 No. 2 (2015)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2015.47.2.3

The ionicliquid [MMIM][DMP] was synthesized from the reactants methyl imidazole [MIM] and trimethylphosphate [TMP] and verified using 1HNMR and FTIR. Coconut coir dust was pretreated with a 1% alkaline solution.Its crystalline structure increased significantly due to the dissolution of lignin and hemicelluloses under alkaline conditions, exposing the cellulose. After NaOH and IL were employed, the XRD showed that peak (002) decreased significantly and peak (101) almost vanished. This significant decrease in crystallinity was related to the alteration of the substrate from the cellulose I structure to the cellulose II structure. The pretreated substrates were hydrolyzed to convert them to reducing sugars by pure cellulase and xylanase,and the reaction was conducted at 60°C, pH 3, for 12 or 48 hours. The yields of sugar hydrolyzed from untreated and NaOH-pretreated substrates were 0.07 and 0.12 g sugar/g lignocellulose, respectively. Pretreatment with IL or the combination of NaOH+IL resulted in yields of reducing sugars of 0.11 and 0.13 g/g, respectively. These findings showed that IL pretreatment of the high-lignin lignocellulose is a new prospect for the economical manufacture of reducing sugars and bioethanol in the coming years.

The Effect of Nutrients Mixture on The Biomass and Lipid Production from Microalgae Botryococcus braunii Mutated by UV-C Rays Thea Prastiwi Soedarmodjo; Hakun Wirawasista Aparamarta; Arief Widjaja
Jurnal Rekayasa Proses Vol 15, No 2 (2021)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.69228

Nutrient is one of the most important factors in the growth of microalgae. This research was conducted to study the effect of nutrient mixture on the biomass and lipid production of Botryococcus braunii. Microalgae B. braunii was cultivated in the commercial nutrient medium of agricultural fertilizer combinations of ammonium sulphate (ZA), urea, and triple superphosphate (TSP). Before the cultivation process, B. braunii was exposed to UV-C rays (254 nm) for 3 minutes. The concentration and type of fertilizer as a nitrogen source divided into four types of mixtures, namely FM-1, FM-2, FM-3, and FM-4 were compared with Walne nutrients to study their effects on microalgae growth and lipids. FM-1 consisting of 150 mg/L of ZA, 7.5 mg/L of urea, and 25 mg/L of TSP led to the best growth for native and mutated microalgae strains compared to Walne nutrients and other nutrient mixtures. The mutated microalgae showed less growth than the native microalgae strains. However, the mutation process significantly increased the lipid content in the microalgae. In native microalgae strains, FM-4 consisting of 136.3 mg/L of urea and 50 mg/L of TSP produced the lowest lipid at 8.96%. After being exposed to UV-C rays, the lipids in FM-4 medium increased to 55.11%. The results show that the use of commercial fertilizers and exposure to UV-C rays on microalgae have high potential in preparing lipids as raw material for biodiesel which can be effectively applied in large-scale microalgae cultivation.

Effect of Dilute Acid Pretreatment of Vegetable Waste on Sugar Production and Inhibitor Formation Denistira Fazlur Rahman; Hakun Wirawasista Aparamarta; Arief Widjaja
IPTEK The Journal for Technology and Science Vol 31, No 1 (2020)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Vegetable waste is an organic waste with high cellulose and hemicellulose and low lignin content. The cellulose and hemicellulose chains can be broken down by pretreatment using sulfuric acid to obtain reducing sugar. To avoid the formation of degradation products that have the potential as inhibitor compounds, the temperature of the pretreatment operation was carried out at 121 and 125 for 60 minutes with sulfuric acid concentrations varying from 0.5% to 1.5% (v/v). The solid and liquid ratio (S/L) was 5% (w/v). From the experiments, the highest total reducing sugars of 7.068 g/L was obtained by pretreatment conditions at 121 for 60 minutes with a sulfuric acid concentration of 1% (v/v). Meanwhile, the lowest total reducing sugar of 2.764 g/L was produced during the pretreatment operating conditions at 125 for 60 minutes with a sulfuric acid concentration of 1% (v/v). Under the present experimental condition, it was found that only a low level of degradation product was formed, which ensures excellent performance of bacterial growth in the subsequent fermentation process.

Preliminary Study of Reducing Sugar Production from Coconut Husk by Enzymatic Hydrolysis Using Chitosan Immobilized Crude and Commercial Cellulase Afan Hamzah; Muhammad Nurul Hakim; Baiq Firyal Salsabilla Safitri; Nurul Maziyah; Laila Nur Rahmah; Hanny F Sangian; Soeprijanto Soeprijanto; Arief Widjaja
IPTEK The Journal for Technology and Science Vol 31, No 1 (2020)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

The objective of this research was to study the production of sugar from coconut husk using immobilized crude and commercial cellulose, including temperature and mixing speed during immobilization. The enzyme from Aspergillus Niger was immobilized on chitosan alone and cross-linked with Glutaric Dialdehyde (GDA). Coconut husk waste was grinded and chemically pretreated using NaOH 1% (w/v). Fourier Transform Infrared Spectroscopy (FT-IR) measurement revealed that enzyme was covalently bonded to the support. Cellulose immobilized on chitosan cross-linked with GDA produced more sugar than immobilized on chitosan alone. Both the crude and commercial enzyme had their yield decreased after immobilization. Despite its less enzyme coupled on micro-sized chitosan, reducing sugar yielded by an immobilized enzyme on micro-sized chitosan had a competitive result with macro-sized chitosan. This may due to decreasing mass transfer resistance when using a smaller size of chitosan. Several important factors such as temperature, mixing speed, and purity of enzyme responsible for the performance of sugar produced from insoluble cellulose using cellulose immobilized on insoluble support was thoroughly discussed.

The Effect of Marine Fish Biomass Stock Reduction to Fishers Revenue (A Case Study of Sardinella Lemuru Fisheries on Bali Strait) Ratna Purwaningsih; Sjarief Widjaja; Sri Gunani Partiwi
IPTEK The Journal for Technology and Science Vol 22, No 3 (2011)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v22i3.73

Stock assessment studies indicate that Sardinela Lemuru fisheries of Bali strait have been overfishing. This research attempts to (1) Identify the effect of biomass stock reduction to fishers revenue per trip, (2) Analyze the economic feasibility study for purse seine of Muncar, Banyuwangi. System Dynamic approach is used for simulation modeling. Simulation output shows a strong correlation between fish stock reduction and fisher revenue. The growth of fishing effort per year results on the reduction of catch per unit effort and total catch per year. Feasibility study concludes that purse seine (30 GT) which operates 120 trips per year is no longer a profitable business since 2020.

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.69228

Strategi Produktivitas Tenaga Kerja Dan Daya Saing Studi Kasus Galangan Kapal Kawasan Pulau Batam Dan Jawa Bagiyo Suwasono; Sjarief Widjaja; Ahmad Zubaydi; M. Zaed Yuliadi
INTERNATIONAL RESEARCH JOURNAL OF BUSINESS STUDIES Vol 3, No 2 (2010): August-November 2010
Publisher : Universitas Prasetiya Mulya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21632/irjbs.3.2.53

The strength of international competitiveness encouraged a shipyard to reduce cost of materials and labor. Therefore, a shipyard did a measurement to improve the rationalization toward labor productivity. This study aimed to compare the path model from strategies of labor productivity and competitiveness of medium size shipyard in region of Batam and Java. The normality test of questionnaire data at 200 respondents who are competent in the feld of shipbuilding through the ratio of skewness and kurtosis did not show normal distribution from the data. Test of model feasibility through PLS algorithm and bootstrapping showed moderate criterion and no signifcant diference in the variable path for both regions. The frst latent variable: shipyard competitiveness is infuenced by the strategic policy and labor productivity, while the second latent variable: labor productivity is infuenced by work activity, strategic policy, and corporate culture. Test of model segmentation through FIMIX-PLS showed good criterion and osignifcant diference in the interaction of variable heterogeneity for both regions. The fnal result of shipyards PLS path modeling showed a consistent relationship between strategic policy and labor productivity in order to increase the Indonesian shipyard competitiveness.

Pengembangan Model Simulasi Kebijakan Pengelolaan Ikan Berkelanjutan Ratna Purwaningsih; Sjarief Widjaja; Sri Gunani Partiwi
Jurnal Teknik Industri: Jurnal Keilmuan dan Aplikasi Teknik Industri Vol. 14 No. 1 (2012): JUNE 2012
Publisher : Institute of Research and Community Outreach - Petra Christian University

Stock assessment studies of Sardinella Lemuru Bali strait indicate overfishing. The growth of fishing vessel numbers result on fish biomass stock reduction. Sustainable fishery management in overfishing area can be done by limiting number of fishing effort. There are three kinds of methods approach on determine number of fishing effort and total allowed catch (1) Maximum Sustainable Yield (MSY), (2) Maximum Economic Yield (MEY) and (3)Maximum Social Yield (MScY). Sustainable fishery has three main aspect as its indicators; ecology, economic and social. This research attempts to simulate three kinds of methods to the indicators of sustainable fishery (1) biomass fish stock as ecological aspect, (2) profit of purse seine fishing vessel as economical aspect and (3) numbers of fishers involved in the business of marine capture fishery represents social aspect. System dynamic method and powersim software are used in simulation model. Simulation output shows that fish biomass stock can be maintain in sustainable level by applied fishery policy. Limiting number of fishing effort create balancing between fish stock natural growth and fish harvest. This policy starts to apply on year 2010 in simulation model and run until 2030 to forecast future condition of fish biomass stock.

Co-Authors Achmad Chumaidi, Achmad Achmad Zubaydi Adi Soeprijanto Aditya Dwi Saputra Adrian Nur Adrian Nur Afan Hamzah, Afan Agra Bachtiar Ahmad Zubaydi Akbarningrum Fatmawati Akbarningrum Fatmawati Akhmad Basuki Widodo Al-Ghifari, Admiral Yagi Anwar, Nadiem Aparamarta, Hakun Wirawasista Aparamarta, Hakun Wirawista Apol, Tabina Raissa Ari Anggoro Arif , Irfan Syarief Artaraharja, Yoseph Daniswara Bagiyo Suwasono Bagiyo Suwasono Bagiyo Suwasono Bagiyo Suwasono, Bagiyo Baiq Firyal Salsabilla Safitri Candra Wijaya, Candra Debra Arlin Puspasari Debra Arlin Puspasari Denistira Fazlur Rahman Desi Liah Martasari Desy Nurwijayanti Dwina Moentamaria Eny Setyowati F Ferry Fadilah, Siska Nuri Firmansyah, Arfian Alwi Fredi Susanto Hanny F. Sangian Hasanudin Hellen Kartika Dewi Hellen Kartika Dewi Hermawan, Yuda Apri Heru Setyawan I Nyoman Budiantara I. Wuled Lenggoro Ilham Alamsah Ilham Alamsyah Integrity, Justian Immanuel Irfan Albana Irfin, Zakijah Irma Nurhanifah Fenda Putri Jayyid Zuhdan Junaidi Kristian Junaidy Kristian Junaidy Kristian Junianti, Fitri Kamila Adila Muslim Karima, Nur Kurniawan Candra Eka Prasetya Mamuji Putra Laila Nur Rahmah Laila Nur Rahmah Lidya Lorenta Sitompul Lieke Riadi M Musmariadi M. Rasyid, Daniel M. Zaed Yuliadi Ma'ruf, Buana Marcus Tukan Maulidarsyah, Muhammad Fauzan Muhammad Nurul Hakim Muharja, Maktum Mukti Mulyawan Nadiem Anwar Novandira, Belva Angeline Nur Fadhilah Nur Fadhilah Nurkhamidah , Siti Nurul Maziyah Nurul Maziyah Panunggal, Eko Patdono Suwignjo Pertiwi, Urania Noor Lintang Rachma, Fanina Aulia Ratna Purwaningsih Ratna Purwaningsih Ratna Purwaningsih Rizki Fitria Darmayanti Rohmah, Ika Putri Nikmatur Samsudin Affandi Sangadji, Ningsi Lick Setiyo Gunawan Silvya Yusnica Agnesty Silvya Yusnica Agnesty Silvya Yusnica Agnesty Silvya Yusnica Agnesty Siska Nuri Fadilah Siska Nuri Fadilah Soedarmodjo, Thea Prastiwi Soegiono, Soegiono Sri Gunani Partiwi Sri Gunani Partiwi Sugeng Winardi Sukma Rahma Sukma Rahma Sukmawati Rahma Tantular Nurtono Thea Prastiwi Soedarmodjo Tri Achmadi Tri Widjaja Winardi, Sugeng Yakub Hendrikson Manurung Yakub Hendrikson Manurung Yuliadi, M. Zaed Zaed Yuliadi Zaed Yuliadi, Zaed Zubaydi, Ahmad Zuhroh, Saiyyidah Tus

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