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All Journal Reaktor International Journal of Renewable Energy Development TEKNIK Rotasi METANA BERKALA FISIKA JURNAL KIMIA SAINS DAN APLIKASI JURNAL TEKNOLOGI KIMIA DAN INDUSTRI Analisis: Jurnal Studi Keislaman Geoplanning : Journal of Geomatics and Planning Jurnal Riset Pendidikan Matematika Bulletin of Chemical Reaction Engineering & Catalysis Jurnal Riset Industri Mesin JUPE : Jurnal Pendidikan Mandala Universitas Muhammadiyah Yogyakarta Undergraduate Conference Proceeding Bulletin of Chemical Reaction Engineering & Catalysis Journal of Chemical Engineering Research Progress JURNAL REKAYASA KIMIA & LINGKUNGAN
I. Istadi
Department Of Chemical Engineering, Diponegoro University, Jl. Prof. Soedarto, Kampus UNDIP Tembalang, Semarang 50239
Agriculture, Biological Sciences & Forestry 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 Energy Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mathematics Mechanical Engineering Physics Public Health Social Sciences

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Back-matter and Author Guidelines Istadi, Istadi
TEKNIK Vol 36, No 1 (2015): (Juli 2015)
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (569.477 KB) | DOI: 10.14710/teknik.v36i1.8756

Abstract

PENGARUH SIFAT FISIK DAN STRUKTUR MINERAL BATU BARA LOKAL TERHADAP SIFAT PEMBAKARAN Bayuseno, Athanasius Priharyoto; Sulistyo, Sulistyo; Istadi, Istadi
ROTASI Volume 10, Nomor 2, April 2008
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3683.926 KB) | DOI: 10.14710/rotasi.10.2.26-31

Abstract

Tujuan penelitian yang dilakukan adalah mengkaji secara seksama tentang potensi kualitas batubara Indonesia yang diambil dari sumber lokal dan selanjutnya menerapkan prosedur/teknologi penyiapan batubara dalam usaha meningkatkan penyalaan dan pembakaran. Sasaran utama didalam teknologi penyiapan batubara diarahkan pada peningkatan penyalaan (ignition) serta hasil pembakaran yang bersih dengan penurunan emisi karbon dioksida dan belerang. Selanjutnya penelitian ini juga mengkaji tentang prospek pengkayaan (enrichment) batubara dalam proses penyiapan batubara lokal. Metode ini diharapkan dapat menaikkan kecepatan penyalaan dan pembakaran nyala api batubara serbuk. Perubahan sifat fisik dan kimia serta struktur mineral sebelum dan setelah proses penyiapan dianalisa dengan metode XRF untuk komposisi kimia dan diffrakasi sinar-X (XRD) untuk komposisi mineral. Sementara nilai kalor batubara dianalisa dengan Bomb Kalorimeter. Pada dasarnya batubara lokal memiliki kandungan mineral utama seperti kaolinite, quartz, jarosite, illite maupun pyrite. Sementara nilai kalor yang dimiliki batubara lokal berkisar antara 4000 -6000 cal/gr dan LOI untuk empat macam batubara berkisar 97-99%. Sebaliknya pengaruh proses pencucian dengan air tidak meningkatkan nilai kalor batubara yang signifikant. Dilain pihak pelaksanaan penelitian ini juga membuat briket bahan bakar batubara dengan campuran polimer dan molase termasuk prosedur mengkaji tingkat penyalaan batubara. Hasilnya menunjukkan bahwa briket batubara dari campuran polyethelene meningkatkan nilai kalor dan mempercepat pembakaran. Dari penelitian ini dapat disimpulkan bahwa kualitas batubara produk lokal tergolong batubara dengan nilai kalor rendah dan perlu penelitian lanjutan dalam meningkatkan kualitas agar bisa kompetitif dengan produk batubara impor.
Karakterisasi Katalis CaO dan Uji Aktivitas pada Kinetika Reaksi Transesterifikasi Minyak Kedelai Pratigto, Setiarto; Istadi, Istadi; Wardhani, Dyah Hesti
METANA Vol 15, No 2 (2019): Desember 2019
Publisher : Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1178.735 KB) | DOI: 10.14710/metana.v15i2.25106

Abstract

Penelitian ini akan mengkaji kinetika reaksi transesterifikasi minyak kedelai dengan metanol menggunakan katalis CaO dengan parameter rasio mol reaktan terhadap konversi metil ester yang digunakan untuk menentukan persamaan kecepatan reaksi. Katalis CaO digunakan untuk reaksi transesterifikasi karena memiliki kekuatan basa yang tinggi, ramah lingkungan, kelarutan yang rendah dalam metanol. Kinetika reaksi untuk reaktor batch dihitung saat reaksi berlangsung berdasarkan rejim surface area limited yang menentukan. Tujuan penelitian ini untuk mengetahui bentuk persamaan kecepatan reaksi transesterifikasi minyak kedelai dan metanol menggunakan katalis CaO menurut metode differential reactor. Penelitian dilakukan dengan reaksi transesterifikasi minyak kedelai dan metanol dengan katalis CaO dengan variabel bebas perbandingan mol reaktan. Hasil penelitian mengemukakan metanol teradsorpsi di permukaan katalis dan trigliserida tidak teradsorpsi di permukaan katalis menunjukkan mekanisme reaksi katalitik Eley-Rideal. Persamaan kecepatan reaksi dapat digunakan dalam perancangan reaktor, sehingga hubungan antara konversi trigliserida menjadi biodiesel dengan kebutuhan berat katalis dan volume reaktor yang diperlukan dapat diprediksi. This study will examine the kinetics of the transesterification reaction of soybean oil with methanol using a CaO catalyst with the parameters of the mole ratio of reactants to the conversion of methyl esters used to determine the reaction velocity equation. CaO catalyst is used for transesterification reaction because it has high base strength, environmentally friendly, low solubility in methanol. The reaction kinetics for a batch reactor are calculated when the reaction takes place based on a decisive surface area limited regime. The purpose of this study was to determine the shape of the speed equation for the transesterification of soybean oil and methanol using a CaO catalyst according to the differential reactor method. The research was carried out with the transesterification reaction of soybean oil and methanol with a CaO catalyst with a free variable ratio of reactant moles. The results of the study revealed that methanol adsorbed on the surface of the catalyst and triglycerides not adsorbed on the surface of the catalyst showed an Eley-Rideal catalytic reaction mechanism. The reaction speed equation can be used in reactor design, so the relationship between the conversion of triglycerides to biodiesel with the required catalyst weight and the reactor volume required can be predicted.
Pengaruh Laju Molar Mn Larutan Terhadap Mikrostruktur Lapisan Tipis GaN:Mn yang Dideposisi di atas Substrat Si Menggunakan Metode Sol-Gel Sutanto, Heri; Hidayanto, Eko; Nurhasanah, Iis; Istadi, Istadi
BERKALA FISIKA Vol 14, No 2 (2011): Berkala Fisika
Publisher : BERKALA FISIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (306.984 KB)

Abstract

A thin layer of material deposition of GaN: Mn by sol-gel method has done using spin-coating technique. Solution of gallium-citrate-amine maganese-Ga2O3 synthesized using as a source of Ga and Mn MnO2 as the source. Solution varied with the mole fraction solution of 60-80% Mn. Brown crystals that formed subsequently dissolved in ethylenediamine to form a gel. Subsequent gel superimposed on top of Si substrates with a spin-coater at a rate of 1100 rpm. Layers formed at temperatures of 900oC and then disintering in UHP N 2 gas environment to form the decomposition of GaN: Mn. The results of spectral analysis of energy dispersive X-ray (EDX) showed incorporation of Mn into the GaN mole fraction increased with the addition of a solution of Mn in the solution used. EDX Test results show that thin films of GaN: Mn impurity contained carbon (C) up to 36.71%. Image scanning electron microscopy (SEM) a thin layer of GaN: Mn shows in general have been obtained surface roughness (rms) morphology of the layer reaches the order of nanometers up to 24.36 nm. From the results already obtained show that the sol-gel deposition method has been able to produce a thin layer of magnetic semiconductors with a nearly homogeneous surface morphology. Thus the sol-gel method could be developed for alternative methods of deposition of thin layers that are economical and simple. Key words: GaN: Mn, CSD, Thin Layer, Mn incorporation.
Mikrostruktur Semikonduktor GaN di Atas Substrat Silikon Dengan Metode Sol-Gel Sutanto, Heri; Nurhasanah, Iis; Istadi, Istadi; Maryanto, Maryanto; Ambikawati, Wahyu; Marlini, Nofi
BERKALA FISIKA Vol 13, No 2 (2010): Berkala Fisika
Publisher : BERKALA FISIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1874.942 KB)

Abstract

Gallium nitride (GaN) semiconductor thin films have been successfully deposited on Si substrate (004) by sol-gel method. Gel prepared from the crystal gallium-citrate-amines. These crystals formed from a solution containing the ions Ga+3 and citric acid (CA). Gel in place on the substrate and then rotated with a speed of 1100 rpm. The gel layers are obtained and then placed on the programmable furnace. Deposition temperature varied of 800, 900 and 1000oC in a nitrogen gas environment during 2 hour. The crystal quality of GaN thin films have characterized by XRD measurement. The surface morphology and cross section of the films observed by SEM. The film compositions determined by EDX characterization. The results showed that all the GaN thin films on silicon substrate have oriented polycrystalline structure. The crystal quality of GaN film is formed is influenced by the deposition temperature. In a deposition temperature range is used, increasing the deposition temperature can improve the crystal quality of GaN films.   Keywords: GaN Thin Films; Spin-Coating Technique; Silicon Substrate
Backmatter (Publication Ethics, Copyright Transfer Agreement Form) Istadi, Istadi
Bulletin of Chemical Reaction Engineering & Catalysis 2020: BCREC Volume 15 Issue 1 Year 2020 (April 2020)
Publisher : Department of Chemical Engineering - Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.15.1.7239.App.1-App.5

Abstract

Backmatter (Publication Ethics, Copyright Transfer Agreement Form) Istadi, Istadi
Bulletin of Chemical Reaction Engineering & Catalysis 2020: BCREC Volume 15 Issue 2 Year 2020 (August 2020)
Publisher : Department of Chemical Engineering - Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.15.2.8536.App.1-App.5

Abstract

Backmatter (Publication Ethics, Copyright Transfer Agreement Form)
Effect of Temperature on Plasma-Assisted Catalytic Cracking of Palm Oil into Biofuels Istadi, I.; Riyanto, Teguh; Buchori, Luqman; Anggoro, Didi Dwi; Saputra, Roni Ade; Muhamad, Theobroma Guntur
International Journal of Renewable Energy Development Vol 9, No 1 (2020): February 2020
Publisher : Center of Biomass & Renewable Energy, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/ijred.9.1.107-112

Abstract

Plasma-assisted catalytic cracking is an attractive method for producing biofuels from vegetable oil. This paper studied the effect of reactor temperature on the performance of plasma-assisted catalytic cracking of palm oil into biofuels. The cracking process was conducted in a Dielectric Barrier Discharge (DBD)-type plasma reactor with the presence of spent RFCC catalyst. The reactor temperature was varied at 400, 450, and 500 ºC. The liquid fuel product was analyzed using a gas chromatography-mass spectrometry (GC-MS) to determine the compositions. Result showed that the presenceof plasma and catalytic role can enhance the reactor performance so that the selectivity of the short-chain hydrocarbon produced increases. The selectivity of gasoline, kerosene, and diesel range fuels over the plasma-catalytic reactor were 16.43%, 52.74% and 21.25%, respectively, while the selectivity of gasoline, kerosene and diesel range fuels over a conventional fixed bed reactor was 12.07%, 39.07%, and 45.11%, respectively. The increasing reactor temperature led to enhanced catalytic role of cracking reaction,particularly directing the reaction to the shorter hydrocarbon range. The reactor temperature dependence on the liquid product components distribution over the plasma-catalytic reactor was also studied. The aromatic and oxygenated compounds increased with the reactor temperature.©2020. CBIORE-IJRED. All rights reserved
Biofuels Production from Catalytic Cracking of Palm Oil Using Modified HY Zeolite Catalysts over A Continuous Fixed Bed Catalytic Reactor Istadi, I.; Riyanto, Teguh; Buchori, Luqman; Anggoro, Didi D.; Pakpahan, Andre W. S.; Pakpahan, Agnes J.
International Journal of Renewable Energy Development Vol 10, No 1 (2021): February 2021
Publisher : Center of Biomass & Renewable Energy, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/ijred.2021.33281

Abstract

The increase in energy demand led to the challenging of alternative fuel development. Biofuels from palm oil through catalytic cracking appear as a promising alternative fuel. In this study, biofuel was produced from palm oil through catalytic cracking using the modified HY zeolite catalysts. The Ni and Co metals were impregnated on the HY catalyst through the wet-impregnation method. The catalysts were characterized using X-ray fluorescence, X-ray diffraction, Brunauer–Emmett–Teller (BET), Pyridine-probed Fourier-transform infrared (FTIR) spectroscopy, and Scanning Electron Microscopy (SEM) methods. The biofuels product obtained was analyzed using a gas chromatography-mass spectrometry (GC-MS) method to determine its composition. The metal impregnation on the HY catalyst could modify the acid site composition (Lewis and Brønsted acid sites), which had significant roles in the palm oil cracking to biofuels. Ni impregnation on HY zeolite led to the high cracking activity, while the Co impregnation led to the high deoxygenation activity. Interestingly, the co-impregnation of Ni and Co on HY catalyst could increase the catalyst activity in cracking and deoxygenation reactions. The yield of biofuels could be increased from 37.32% to 40.00% by using the modified HY catalyst. Furthermore, the selectivity of gasoline could be achieved up to 11.79%. The Ni and Co metals impregnation on HY zeolite has a promising result on both the cracking and deoxygenation process of palm oil to biofuels due to the role of each metal. This finding is valuable for further catalyst development, especially on bifunctional catalyst development for palm oil conversion to biofuels.
Backmatter (Publication Ethics, Copyright Transfer Agreement Form) Istadi, Istadi
Bulletin of Chemical Reaction Engineering & Catalysis 2020: BCREC Volume 15 Issue 3 Year 2020 (December 2020)
Publisher : Department of Chemical Engineering - Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.15.3.9881.App.1-App.5

Abstract

Backmatter (Publication Ethics, Copyright Transfer Agreement Form)
Co-Authors Ajeng Riswanti Wulandari Amalia, Rahma Amin N.A.S. Amin Amin Nugroho Aminuyati Anggun Kurniawan Anindita Indriana Aniyati Khoiriyah Anwar Muttaqien, Anwar Anwaruddin Hisyam Ardian D. Yudhistira Ardian Dwi Yudhistira Aribowo, Windarto Atanasius Priharyoto Bayuseno Bahrudin, Moh. Bambang Pramudono Bambang Tri Nugroho Bintang Ayu Kalimantini Chusnul Khotimah D. A. Rahmawati D. Intaningrum Daniel Setiyo Nugroho Dian Rahmayanti Didi D. Anggoro Didi D. Anggoro Didi D. Anggoro Didi D. Anggoro Didi Dwi Anggoro Dinara, Daniella Cipta Dini Wulandari Dorothy Hoo Wei Ling Dyah Hesti Wardhani Eko Hidayanto Fachmy Adji Pangestu Setiawan Febriansyar, Rosyad Adrian Haniif Prasetiawan Heri Mulyanti Heri Sutanto Herlina Hidayati Iis Nurhasanah Inshani Utami Inshani Utami Karimullah, Suud Sarim Kursius, Catherine M. Kursius, Catherine Mentaya Luqman Buchori M.C.T. Wahyu Utami Maryanto - Muhamad, Theobroma Guntur Nani Harihastuti, Nani New Pei Yee Nofi Marlini Nor Aishah Saidina Amin Nor Aishah Saidina Amin Nor Aishah Saidina Amin P Purwanto Pakpahan, Agnes J. Pakpahan, Andre W. S. Permatasari, Astrid Eka Purwanto . Purwanto Purwanto Purwanto Purwanto Putut Marwoto Rahmat Gernowo Rakhmawati, Astri Ratna Dewi Kusumaningtyas Riyanto, Teguh Roikhatus Solikhah Roikhatus Solikhah Salsabila, Unik Hanifah Saputra, Roni Ade Sitompul, J. P Slamet Priyanto Suherman Suherman Sulistyo Sulistyo Teguh Riyanto Teuku Irfan Maulana Udin Mabruro Wahyu Ambikawati