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EFFECT OF MULTI PASS HIGH ENERGY MILLING ON MORPHOLOGY AND RHEOLOGICAL PROPERTIES OF CARBON NANOTUBES Darsono, Nono
Metalurgi Vol 29, No 2 (2014): Metalurgi Vol.29 No.2 Agustus 2014
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (737.687 KB) | DOI: 10.14203/metalurgi.v29i2.281

Abstract

EFFECT OF MULTI PASS HIGH ENERGY MILLING ON MORPHOLOGY AND RHEOLOGICALPROPERTIES OF CARBON NANOTUBES. Multi pass high energy milling was utilized in order to cut anddisperse carbon nanotubes (CNTs) suspension. The purpose is to maintain the crystallinity and suppress thedamage. One until five passes gave increase in D- to G-band ratio which means increasing the damage, at thevalue range from 0.1 to 0.2. The ratio is still lower compare 2-hour high energy milling and 120-hourconventional ball milling, at the value of 0.5 – 0.3. The rheological properties was not altered dramatically. It isindicated that the milling only tears down the aggeregates into small fraction of entangled CNTs treads.
Dipole Magnetization Effect to Kerosene Characteristics Chalid, Mochamad; Saksono, Nelson; Adiwar, Adiwar; Darsono, Nono
Makara Journal of Technology Vol. 9, No. 1
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Dipole Magnetization Effect to Kerosene Characteristics. Investigation of kerosene characteristics has been done by ex-situ dipole magnetization. The results show that magnetization technique can be able to influence kerosene characteristics. Polarity and viscosity of the kerosene are observed by measuring refractive index and viscosity. An hour of 4330 Gauss flux magnetic will increase refractive index from 1.447 to 1.449 and decrease the viscosity from 1.278 to 1.256. Those changing support de-clustering occurrence and polarity increment of kerosene molecule. Gas chromatography and infrared result show that those changing do not alter kerosene structure and composition.
Corrosion behavior of super austenitic stainless steel, Duplex 2205 and 316L in sulfamic acid environment Roszardi, Bashari Rohululloh; Riastuti, Rini; Budiarto, Wahyu; Darsono, Nono; Syahid, Adi Noer
Jurnal Pendidikan Teknologi Kejuruan Vol 4 No 4 (2021): Regular Issue
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/jptk.v4i4.24323

Abstract

Currently, sulfamic acid as a primary chemical industrial material is ubiquitous. One of its uses is a sweetener. Due to its corrosive nature, it is necessary to use a suitable container to avoid contamination of the solution. Corrosion behavior of super austenitic stainless steel, duplex 2205, and 316L uncovered to sulfamic acid in diverse attention at ambient temperature had been investigated. Concentration Weight loss method, Potentiodynamic Polarization, and Electrochemical Impedance Spectroscopy (EIS) examined the corrosion rate. The result showed that the corrosion rate of material increased with the increasing concentration of sulfamic acid. Super austenitic stainless steel has higher corrosion resistance than duplex 2205 and 316L.
Synthesis and Characterization of Cu-Cr-O Phase with H2SO4 Solvent Using Sol-Gel Method Rangkuti, Yusridah; Humaidi, Syahrul; Maulid, Nurul; Imaduddin, Agung; Herbirowo, Satrio; Nugraha, Heri; Darsono, Nono
Journal of Technomaterial Physics Vol. 5 No. 1 (2023): Journal of Technomaterial Physics
Publisher : Talenta Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32734/jotp.v5i1.10897

Abstract

This study used the cast-in-situ method to make concrete based on rice husk ash and pineapple leaf fiber. Rice husk ash and pineapple leaf fiber were used as the cement substitutes with different variations: 0%, 2.5%, 5%, and 7.5%. Parameters examined in this study included density, porosity, water absorption, flexural strength, and compressive strength using a universal testing machine and Material Testing equipment, which were then analyzed morphologically using SEM-EDX. The result showed a density of  2.510 × 103 − 2.451 × 103 kg/m3, porosity of 7.64 – 5.73 %, water absorption of 0.296 % – 0.243 %, compressive strength of 23.66 – 16.45 MPa, flexural Strength of 33.3 – 25.3 MPa. The morphological analysis showed that the rice husk ash and pineapple leaf fiber addition was responsible for the concrete's porous structure in this study has a porous structure. The EDX analysis result exhibited a high carbon percentage.
Jumping Ship Crew In Cruise Ship Crew Recruitment At PT. CWT Nabila Nurul Ikhlas; Mustain, Iing; Abdurohman; Darsono, Nono
Nama Jurnal Akmi Vol 6 No 2 (2024): Jurnal Sitektransmar November 2024
Publisher : LPPM AKMI SUAKA BAHARI CIREBON

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51578/j.sitektransmar.v6i2.80

Abstract

The purpose of the study was to determine the flow of the cruise ship crew recruitment process at PT. CWT, to find out what obstacles are experienced when recruiting cruise ship crew, and to find out a crew to meet the targets of the Norwegian Cruise Line. The study used a qualitative descriptive approach to case studies in the selected objects. Data collection in the study used data triangulation, namely observation, interviews, and documentation. The object of the study is PT. CWT Bandung. The results of the study were obtained. There are several factors that make crew take a long time to join or even cancel joining due to several factors that still often occur. The factors found in the recruitment process for ship crew at PT. CWT are often incomplete document requirements from the crew who apply or there are still many crew who are not proficient in English because they are required to take a marlin test whose results must be 70% and the interview must also be in English. Efforts were made to meet the target of Norwegian Cruise Line to always fill every position that was needed, seeking relations such as shipping schools to be informed that there were vacancies for certain positions that were needed.
Fixing cobalt metal onto mordenite through spray impregnation and its evaluation as a catalyst in transforming used coconut cooking oil into bio-jet fuel Saviola, Aldino Javier; Wijaya, Karna; Syoufian, Akhmad; Vebryana, Marini Fairuz; Anggraeni, Widuri; Rozana, Kharistya; Darsono, Nono; Saputra, Dita Adi; Saputri, Wahyu Dita
Communications in Science and Technology Vol 9 No 2 (2024)
Publisher : Komunitas Ilmuwan dan Profesional Muslim Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21924/cst.9.2.2024.1535

Abstract

Given the challenges posed by fossil-based jet fuel, research into bio-jet fuel production has intensified to achieve carbon neutrality. The present work reports a significant breakthrough with the successful conversion of used coconut cooking oil into bio-jet fuel utilizing a cobalt-impregnated mordenite catalyst. Cobalt was introduced to mordenite via the spray impregnation method at a concentration of 2% using a CoCl?·6H?O solution. The resultant catalyst was characterized using FTIR, XRD, NH?-TPD, SAA, FESEM-EDX Mapping, TEM, XPS, and TG/DTA instruments. Hydrotreatment was conducted in a semi-batch reactor at atmospheric pressure, employing H? gas at a flow rate of 20 mL/min and a catalyst-to-feed ratio of 1:200 (w/w) for a duration of 2 h. The addition of cobalt significantly enhanced the efficiency of the hydrotreatment by improving the catalytic performance of mordenite as a support material. The liquid product conversion and total bio-jet fuel yield obtained from the hydrotreatment of used coconut cooking oil using the Co/mordenite catalyst were 60.25% and 51.11%, respectively. The highest selectivity for bio-jet fuel was observed in fraction II (450–550 °C) at 88.90%. This catalyst exhibited sustained performance over three consecutive runs, indicating its potential application in the future biofuel industry. Altogether, this research reveals the possibility of employing used coconut cooking oil as a sustainable and promising feedstock to be converted into bio-jet fuel by hydrodeoxygenation and/or hydrocracking reactions.
Corrosion behavior of super austenitic stainless steel, Duplex 2205 and 316L in sulfamic acid environment Roszardi, Bashari Rohululloh; Riastuti, Rini; Budiarto, Wahyu; Darsono, Nono; Syahid, Adi Noer
Jurnal Pendidikan Teknologi Kejuruan Vol 4 No 4 (2021): Regular Issue
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/jptk.v4i4.24323

Abstract

Currently, sulfamic acid as a primary chemical industrial material is ubiquitous. One of its uses is a sweetener. Due to its corrosive nature, it is necessary to use a suitable container to avoid contamination of the solution. Corrosion behavior of super austenitic stainless steel, duplex 2205, and 316L uncovered to sulfamic acid in diverse attention at ambient temperature had been investigated. Concentration Weight loss method, Potentiodynamic Polarization, and Electrochemical Impedance Spectroscopy (EIS) examined the corrosion rate. The result showed that the corrosion rate of material increased with the increasing concentration of sulfamic acid. Super austenitic stainless steel has higher corrosion resistance than duplex 2205 and 316L.
CORROSION BEHAVIOR OF SUPER AUSTENITIC STAINLESS STEEL, DUPLEX 2205 AND 316L IN SULFAMIC ACID ENVIRONMENT Roszardi, Bashari R; Riastuti, Rini; Budiarto, Wahyu; Darsono, Nono; Syahid, Adi Noer
NUSANTARA : Jurnal Ilmu Pengetahuan Sosial Vol 9, No 2 (2022): NUSANTARA : Jurnal Ilmu Pengetahuan Sosial
Publisher : Universitas Muhammadiyah Tapanuli Selatan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31604/jips.v9i1.2022.85-91

Abstract

Currently, sulfuric acid as a primary chemical industrial material is ubiquitous. One of its uses is a sweetener. Due to its corrosive nature, it is necessary to use a suitable container to avoid contamination of the solution. Corrosion behavior of super austenitic stainless steel, duplex 2205, and 316L uncovered to sulfamic acid in diverse attention at ambient temperature had been investigated. Concentration Weight loss method, Potentiodynamic Polarization, and Electrochemical Impedance Spectroscopy (EIS) examined the corrosion rate. The result showed that the corrosion rate of material increased with the increasing concentration of sulfamic acid. Super austenitic stainless steel has higher corrosion resistance than duplex 2205 and 316L.  
Experimental comparison of air, oil, and liquid nitrogen cooling media on the efficiency of a single-phase transformer Nugraha, Heri; Imaduddin, Agung; Priandana, Eka Rakhman; Hermawan, Asep Dadan; Darsono, Nono; Pramono, Andika Widya; Syahid, Adi Noer; Palaloi, Sudirman; Herbirowo, Satrio; Hendrik, Hendrik
International Journal of Electrical and Computer Engineering (IJECE) Vol 16, No 1: February 2026
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijece.v16i1.pp25-35

Abstract

Transformers are critical component in electric power system, where minimizing energy losses is essential for efficiency and reliability. While ideal transformers operate with zero losses, practical transformers dissipate energy through winding and core losses caused by resistive heating. This study investigates the impact of three cooling media with ambient air, mineral oil, and liquid nitrogen on the efficiency and thermal performance of a 1 kVA single phase copper wound transformer. The experiment applied a resistive load under each cooling condition, recording input and output parameters using a HIOKI power meter model PW3360. Thermal behavior was monitored using infrared thermography and thermocouples. Copper winding resistivity was evaluated using a four-point probe within a cryogenic magnet system. The results show that liquid nitrogen cooling significantly reduced copper resistivity due to low-temperature conditions, achieving a transformer efficiency of 89.9%. Oil cooling improved efficiency to 86.0%, compared to 80.7% with air cooling. Although liquid nitrogen provided the greatest efficiency enhancement, its practical use is limited due to handling complexity and cost. In contrast, oil cooling offers a more feasible and effective solution for improving transformer performance in real world applications. These finding provide valuable insight for optimizing transformer thermal management strategies in power systems.