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All Journal Jurnal Kimia dan Kemasan Prosiding Seminar Nasional Teknoka Ornamen Jurnal Pengkajian dan Penciptaan Seni Kriya Teknologi Indonesia Jurnal Riset Sains dan Kimia Terapan Journal of Materials Exploration and Findings Metalurgi

Nofrijon Sofyan, Nofrijon

Department Of Metallurgical And Materials Engineering, Faculty Of Engineering, Universitas Indonesia, Depok 16424, Indonesia Tropical Renewable Energy Center, Faculty Of Engineering, Universitas Indonesia, Depok 16424, Indonesia

Author-ID : 500631

Arts Humanities Chemistry Computer Science & IT Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology

Published : 12 Documents Claim Missing Document

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Characteristics of Vanadium Doped And Bamboo Activated Carbon Coated LiFePO4 And Its Performance For Lithium Ion Battery Cathode Sofyan, Nofrijon; Alfaruq, Subkhan; Zulfia, Anne; Subhan, Achmad
Jurnal Kimia dan Kemasan Vol. 40 No. 1 April 2018
Publisher : Balai Besar Kimia dan Kemasan

Vanadium doped and bamboo activated carbon coated lithium iron phosphate (LiFePO4) used for lithium ion battery cathode has been successfully prepared. Lithium iron phosphate was prepared through a wet chemical method followed by a hydrothermal process from the starting materials of LiOH, NH4H2PO4, and FeSO4.7H2O. The dopant variations of 0 wt.%, 3 wt.%, 5 wt.%, and 7 wt.% of vanadium and a fixed 3 wt.% of bamboo activated carbon were carried out via a solid-state reaction process each by using NH4VO3 as a source of vanadium and carbon pyrolyzed from bamboo tree, respectively. The characterization was carried out using X-ray Diffraction (XRD) for the phase formed and its crystal structure, Scanning Electron Microscope (SEM) for the surface morphology, Electrochemical Impedance Spectroscopy (EIS) for the conductivity, and battery analyzer for the performance of lithium ion battery cathode. The XRD results show that the phase formed has an olivine based structure with an orthorhombic space group. Morphology examination revealed that the particle agglomeration decreased with the increasing level of vanadium concentrations. Conductivity test showed that the impedance of solid electrolyte interface decreased with the increase of vanadium concentration indicated by increasing conductivity of 1.25 x 10-5 S/cm, 2.02 x 10-5 S/cm, 4.37 x 10-5 S/cm, and 5.69 x 10-5 S/cm, each for 0 wt.%, 3 wt.%, 5 wt.%, and 7 wt.% vanadium, respectively. Vanadium doping and bamboo activated carbon coating are promising candidate for improving lithium ion battery cathode as the initial charge and discharge capacity at 0.5C for LiFePO4/C at 7 wt.% vanadium is in the range of 8.0 mAh/g.

EFFECT OF SINTERING TEMPERATURE ON THE ROLLED COPPER-SHEATHED MONOFILAMENT MgB2 SUPERCONDUCTING WIRE Herbirowo, Satrio; Imaduddin, Agung; Sofyan, Nofrijon; Yuwono, A.H
Teknologi Indonesia Vol 40, No 1 (2017)
Publisher : LIPI Press

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The manufacture of low temperature superconductor (LTS) MgB2 with relatively high critical temperature (Tc = 39K) wire fabricated by powder-in-tube (PIT) is a multi-step process. The main difficulty is that the value of Tc superconductor wire is determined by various factors. MgB2 superconductor has been developed for possible utilization in various practical applications, such as Magnetic Resonance Imaging. The fabrication process of 2 mm rolled-copper sheath monofilament superconductor MgB2 wire using mechanical deformation process, including rolling and drawing, has been carried out. Starting by inserting powders, containing nominal composition of MgB2 into Cu tube with inner ø of 4 mm and outer ø of 6 mm, then they were rolled and drawn into wires (ø 2 mm), subsequently. The process of copper tube rolling was subsequently repeated in order to obtain three samples using added 5% CNT and 10% CNT to the pure MgB2, then were heat-treated at 800°C for 2 hours respectively. The writers evaluated the doping effect of two types multiwall carbon nanotube (MWCNT) with different aspect ratios on MgB2/Cu monofilament wires. Surface morphology was analyzed with SEM, crystal structure of MgB2 with XRD, whereas temperature dependence resistivity with four-point probe Cryogenic Magnet. SEM-EDS images showed that without addition of CNT, the crystal of MgB2 form dispersed uniformly in wire, but when added with 5% and 10% of CNT, the particle dispersed morphology was observed due to substitution of atom C into atom B. In contrast with pure MgB2, however, the pores increased as the CNTs doped increased of up to 5 wt%, makes it hard to identify the critical temperature. The temperature dependence of resistivity results showed that the critical temperatures were detected and kept shifting toward high 40 K with the addition of 10 wt% CNT. XRD analysis showed that some Mg may react with CNT to form MgB4 and graphite. Mg may react with oxygen to form MgO because the Cu sheath is not fully sealed and vacumed.

Integrasi Grafin Oksida Berbasis Larutan sebagai Material Penghantar Lubang pada Sel Surya Hibrid Bulk-Heterojunction (BHJ) Madsuha, Alfian F.; Sofyan, Nofrijon; Yuwono, A. H.
Prosiding Seminar Nasional Teknoka Vol 3 (2018): Prosiding Seminar Nasional Teknoka ke - 3
Publisher : Fakultas Teknik, Universitas Muhammadiyah Prof. Dr. Hamka, Jakarta

Dalam penelitian kali ini, telah didemonstarsikan penggunaan Grafin Oksida (GO) sebagai material pengantar lubang pada sel surya hibrid Bulk-Heterojunction (BHJ). Sebuah metode sederhana digunakan dalam memodifikasi anoda dari sel surya hibrid dengan cara mendeposisi material karbon nano hasil proses larutan diantara kaca transparan indium timah oksida(ITO) dan lapisan fotoaktif. Perngguanan GO ini ditujukan untuk mengganti secara keseluruhan polimer konduktif poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). Dengan penggunaan lapisan GO ini, perbaikan efisiensi konversi energi dari 0,1% menjadi 1,66 % dapat dicapai melalu mekanisme penurunan hambatan seri (RS). Dengan hasil ini GO telah berhasil menunjukkan potensial yang besar untuk digunakan sebagai material pengantar lubang yang efisien pada sel surya hibrid

Aplikasi Motif Batik Tradisional Surakarta Pada Produk Keramik Dinding Dengan Teknik Glasir Prima Yustana; Nofrijon Sofyan; Veronika Kristanti Putri Laksmi
Ornamen Vol 10, No 1 (2013)
Publisher : Institut Seni Indonesia Surakarta

This research was aimed at creating a new prototype ofdecorative wall ceramic characterized by local cultural character.The proposed work was motivated by the traditional batik characterizedby local style of Surakarta on the decorative wall ceramicby using glaze coloring techniques. An experimental study withseveral stages of material testing, firing, and glazing temperaturesas well as coloring motif with glaze techniques has beenperformed. The successful application of the traditional batik onthe ceramic wall with a glaze technique is expected to contributeprimarily to the creative industries. In addition, this decorativewall ceramic products would be able to support the opportunitiesto create new jobs based on the creative economy, in line withthe government program in addressing the unemployment. Theresulting prototype of decorative ceramic wall is also expected toprovide a solution to overcome local art and cultural identity degradationphenomena. Finally, in particular, the results of this studyare expected to (1) generate the description and identification ofthe problems arising in the process of decorative wall ceramicmaking by using glaze technique, (2) provide a new alternativeproducts, and (3) support the era of the creative industry with thecreation of new products that carry local cultural character andas a solution to the creation of a new field for the unemployment.Keyword: Wall Ceramic, Glazing Teqnique, Traditional Batik Surakarta

OBSERVASI LINGKUNGAN : KOMPOSISI DAN STRUKTUR MATERIAL BATUAN GUNUNG MERAPI DI D.I. YOGYAKARTA Imanudin Hidayat; Sunaryo Sunaryo; K.H. Firos Dawwas; Feti Eka Rahayu; Esty Asma Dewanti; Erfan Handoko; Fatah Nurdin; Nofrijon Sofyan; Bambang Soegijono
Jurnal Riset Sains dan Kimia Terapan Vol 3 No 2 (2013): JRSKT - Jurnal Riset Sains dan Kimia Terapan, Volume 3 Nomor 2 Desember 2013
Publisher : Program Studi Kimia Universitas Negeri Jakarta

Dengan tujuan mengetahui komposisi dan struktur yang terkandung dalam batuan pegunungan merapi di Daerah Istimewa Yogyakarta dilakukan observasi lingkungan. Ada tiga jenis batuan yaitu batuan merah, hitam, dan putih. Analisis struktur diketahui dengan difraksi sinar-X phillips radiasi Ka Co. Morfologi batuan diamati dengan scanning electron microscope (SEM). Komposisi batuan dengan menggunakan Energy Dispersive X-ray (EDX). Hasil karakterisasi menunjukkan bahwa semua batuan merupakan batuan kristal dengan komposisi fasa yang dominan untuk batuan merah yaitu SiO2, CaCO3, Al2O3, dan S. Sedangkan pada batuan hitam didominasi dengan kandungan SiO2 dan batuan putih dengan kandungan SiO2 dan S. Struktur mikro ketiga jenis batuan ini memiliki bentuk morfologi yang berbeda. Kata Kunci : Batuan pegunungan, batuan merah, hitam, putih, material kristal. In order to know structure and composition of contents in mountain rocks at Daerah Istimewa Yogyakarta, to be done enviorment observation. Three rocks are red, black, and white rocks. The analysis of crystal structures was examined by X-Ray Diffractometer (XRD) Phillips with Ka Co radiation. Morphology of three rocks was studied using a Scanning Electron Microscope (SEM). The composition of mountain rocks was detected by Energy Dispersive X-ray (EDX). The results shows that mountain rocks are crystal materials that phase composition of red rock are SiO2, CaCO3, Al2O3, and S. Black rock is SiO2 as mayor phase and white rock is consist of SiO2 and S. Microstructure of three rocks has the different morphology. Keywords : mountain rocks, red, black, white rocks, crystal materials.

Characteristics of Sodium Lithium Titanate Synthesized at Different Solid-State Reaction Temperature for Lithium-Ion Battery Anode Yahya, Ilham Nur Dimas; Sofyan, Nofrijon; Khaerudini, Deni Shidqi; Timuda, Gerald Ensang; Priyono, Slamet
Journal of Materials Exploration and Findings Vol. 2, No. 3
Publisher : UI Scholars Hub

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The effect of sintering temperature on the characteristics of sodium lithium titanate (NaLiTi3O7/NaLTO) synthesized at different solid-state reaction temperature and its performance as lithium-ion battery anode has been investigated. The precursors for the synthesis consisted of LiOH.H2O, TiO2, and NaHCO3. The synthesis was performed via solid-state reaction method. The precursors were mixed and sintered at variation temperatures of 900oC, 1000oC, and 1100oC for 2 hours under atmosphere condition. The final product was characterized using X-ray diffraction (XRD) and particle size analyzer (PSA). The XRD analysis showed the main phase of NaLTO with some impurities. PSA analysis showed that the sintering temperature has a significant effect on changes in particle size where the sample at a temperature of 1100oC has the largest particle size of 74.62 µm. The battery was fabricated by firstly mixing NaLTO powder with polyvinylidene fluoride (PVDF) and acetylene black (AB) in a ratio of 85:10:5 wt.% and the mix was then deposited onto copper foil to form NaLTO a sheet. The NaLTO sheet was cut into circular discs with a diameter of 14 mm and were arranged in a sequence of separator, metallic lithium, and electrolyte to form a coin cell in a glove box. Characterization using cyclic voltammetry (CV) and charge-discharge (CD) showed that the NaLTO sintered at 1000oC provided good electrochemical performance with the largest diffusion coefficient of 3.948 x 10-10 m2/s, Coulombic efficiency reached 100%, and a high specific capacity of 65.83 mAh/g.

Residual Stress Measurement of Used Mining Dump Truck Frame for Remanufacturing Purposes Ferdiyanto, David; Sofyan, Nofrijon; Yuwono, Akhmad Herman; Dhaneswara, Donanta
Metalurgi Vol 38, No 3 (2023): Metalurgi Vol. 38 No. 3 2023
Publisher : National Research and Innovation Agency (BRIN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/metalurgi.2023.730

Remanufacturing the main frame of a mining dump truck can save cost, energy, and materials in heavy equipment industries. It also can reduce CO2 emissions for environmental preservation to achieve sustainability. However, since the mainframe received a dynamic load during operation, it presumably leaves accumulated residual stresses in the frame. The residual stress, particularly tensile residual stress, stands out as a primary contributing factor to the initiation of cracks, which may ultimately result in failures. In this paper, the residual stress of the used mining dump truck main frame was identified by modeling simulation using FEA (finite element analysis) and actual measurement using a portable x-ray residual stress analyzer with the cos α method. The results showed that the weld area subjected to dynamic loads exhibited the highest tensile residual stress, reaching approximately +772 MPa. This specific region emerges as a critical area demanding attention during the remanufacturing process. The application of PWHT (post-weld heat treatment) at 400 °C for 1 hour effectively reduced residual stress on the weld joint, predominantly tensile residual stress, by more than 80%.

Effect of Heating Temperature and Die Insert Draft Angle on the Flowability of Hot Forged SCM435 Steel Sofyan, Nofrijon; Heruwiyono, Maulana; Yuwono, Akhmad Herman; Dhaneswara, Donanta
Metalurgi Vol 37, No 2 (2022): Metalurgi Vol. 37 No. 2 Agustus 2022
Publisher : National Research and Innovation Agency (BRIN)

The problem of flowability in a closed forging process for heavy equipment industry is still widely found and this may affect the quality of the resulting product. To obtain the solution for this problem, in this work, the effect of heating temperature and die insert draft angle on the characteristic of hot forged SCM435 steel used for undercarriage track roller has been examined. The workpieces were heated at temperature variations of 1150 °C, 1200 °C, 1250 °C and were hot forged at die insert draft angles of 3°, 5°, and 7° to form undercarriage track roller products. The mechanical properties of the products were characterized through hardness and dimension examination, whereas the microstructure was characterized using an optical microscope. The results showed that increasing the heating temperature and die insert draft angle resulted in good flowability. The best result was obtained from the heating temperature of 1250 °C at the die insert draft angle of 7°, with diameter and height of 191.2 mm and 53.6 mm, respectively. This characteristic of the obtained hot-forged product agreed with that of the specified forging design for the undercarriage track roller

Synthesis of Tin Oxide Nanocrystallites with Various Calcination Temperatures Using Co-Precipitation Method with Local Tin Chloride Precursor Panthoko, Norbert Egan Christo; Septiningrum, Fairuz; Yuwono, Akhmad Herman; Nurhidayah, Eka; Maulana, Fakhri Akbar; Sofyan, Nofrijon; Dhaneswara, Donanta; Lalasari, Latifa Hanum; Arini, Tri; Andriyah, Lia; Firdiyono, Florentinus; Ardianto, Yahya Winda; Pawan, Ria Wardhani
Metalurgi Vol 38, No 1 (2023): Metalurgi Vol. 38 No. 1 2023
Publisher : National Research and Innovation Agency (BRIN)

Indonesia is one of the largest tin metal producers in the world, and one of its derivative products is tin chloride (SnCl4). This material has been used as a raw ingredient for the production of organotin compounds such as methyltin mercaptide for PVC (polyvinyl chloride) plastic industry as a heat stabilizer. On the other hand, this precursor can be used to synthesize SnO2 nanomaterials, which have other strategic potentials, including photocatalysts and solar cell applications. In this study, the synthesis of SnO2 nanocrystallites was carried out using a local tin chloride precursor via the co-precipitation method, followed by a calcination process at temperatures of 300, 400, 500, and 600 °C, for further usage as an ETL (electron transport layer) in a PSC (perovskite solar cell) device. The basic properties characterization was carried out using XRD (X-ray diffraction), ultraviolet-visible (UV-Vis) spectroscopy, and SEM (scanning electron microscopy), while the photocurrent-voltage (I-V) curve photovoltaic performance of the device was performed using a semiconductor parameter analyzer. The characterization results showed that increasing the calcination temperature from 300 to 600 °C increased the average crystallite size from 1.19 to 13.75 nm and decreased the band gap energy from 3.57 to 3.10 eV. The highest PCE (power conversion efficiency) was obtained from the device fabricated with SnO2 nanocrystallites calcined at a temperature of 300 °C, which was 0.0024%. This result was obtained due to the highest transmittance of this sample as compared to others; the higher the transmittance, the better the performance of the ETL, which in turn increased the overall efficiency of the PSC

Comparative Analysis of Risk-Based and Time-Based Inspection Application in Hydrocarbon and Chemical Industries: A Review Azizar, Azizar; Sofyan, Nofrijon
Journal of Materials Exploration and Findings Vol. 3, No. 3
Publisher : UI Scholars Hub

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RBI and TBI strategies are comparatively reviewed in terms of their contribution to maintaining asset integrity for asset owners in the hydrocarbon and chemical industries. The objective is to assess various methods on a cost-efficient and risk-managed operational safety basis. It utilizes common industry standards such as API 580 for RBI, and API 510, API 570, and API 653 for TBI, and also case studies and literature analysis. The analysis of data was conducted to examine how each approach deals with inspection planning and decision-making. They suggest that RBI's risk-based prioritization strategy leads to more effective management of high-risk assets, while TBI is simpler and standardized, but could potentially result in over-inspections or overlook emerging risks. The review thus suggests a customized strategy taking account of both RBI and TBI in order to adequately meet requirements related to operational processes, risk exposure, and compliance.

Co-Authors Achmad Subhan Agung Imaduddin, Agung Akhmad Herman Yuwono Akhmad Herman Yuwono, Akhmad Alfaruq, Subkhan Amalia Sholehah, Amalia Amalia, Ary Yanuar Tri Andika, Geo Surya Andriayani Andriyah, Lia Anne Zulfia Ardianto, Yahya Winda Azizar, Azizar Bambang Soegijono Daniel Kurniawan Dedi Supriadi Deni Shidqi Khaerudini Dhaneswara, Donanta Erfan Handoko Esty Asma Dewanti FATAH NURDIN Ferdiyanto, David Feti Eka Rahayu Florentinus Firdiyono Gerald Ensang Timuda Ghiska Ramahdita, Ghiska Herlince Sihotang, Herlince Heruwiyono, Maulana Ilham Nur Dimas Yahya Imam Akbar, Imam Imanudin Hidayat Islam, Adinda Izzatul K.H. Firos Dawwas Lalasari, Latifa Hanum Madsuha, Alfian F. Martinus Adi Anggoro, Martinus Adi Maulana, Fakhri Akbar Muhammad Hanifuddin Nurhidayah, Eka Panthoko, Norbert Egan Christo Pawan, Ria Wardhani Prima Yustana Satrio Herbirowo, Satrio Saur L. Raja, Saur Septiningrum, Fairuz Shahab, Ahmad Nabil Slamet Priyono Sri Harjanto Sunaryo Sunaryo Tri Arini, Tri Veronika Kristanti Putri Laksmi Wardana, Afif Winarto Winarto Yahya, Ilham Nur Dimas Yuwono, A. H. Yuwono, A.H

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