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Sagir Alva
Universitas Mercu Buana
Aerospace Engineering Automotive Engineering Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Control & Systems Engineering Education Electrical & Electronics Engineering Energy Engineering Industrial & Manufacturing Engineering Languange, Linguistic, Communication & Media Materials Science & Nanotechnology Mathematics Mechanical Engineering Other

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STUDY OF FINITE DIFFERENCE METHOD IN HEAT FLOW SIMULATION OF TWO-CHAMBER THERMOS SEPARATOR MADE OF POLYPROPYLENE USING MATLAB APPLICATIONS Pandriana, Aap; Pudjiwati, Sri; Alva, Sagir; Tarigan, Kontan; Sudarma, Andi Firdaus; Khaerudini, Deni Shidqi
Jurnal Teknik Mesin (Journal Of Mechanical Engineering) Vol 13, No 2 (2024)
Publisher : Universitas Mercu Buana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22441/jtm.v13i2.27803

Abstract

Heat transfer can be defined as transfer of energy from one area to another as a result of temperature differences in objects. This indicates heat transfer not only explains how heat energy is transferred from one object to another, but can also predict the rate of heat transfer that occurs under certain conditions. In this case, what is related to the heat flow model equation is two-chamber thermos separator where the separator is made of polypropylene. This separator functions to prevent the flow of heat from one side to the other side of the thermos tube. Polypropylene is included in the insulator category, although heat transfer still occurs. The heat transfer will be calculated using the finite difference method in parabolic partial differential equations using the Matlab application. The heat transfer process is assumed to occur by conduction, with a separator length of 1 cm. Assume the first side of the divider has a right temperature of 100°c, and the other side 20°c. The temperature point measured on the separator is located in the center of the separator. After completing the solution using the Matlab application with the finite difference method, a heat transfer flow simulation was obtained in the two-chamber thermos separator which shows the heat flow transfer at any time. At 0.1 seconds the temperature at T1 is 2.4°c, while at 10 seconds  is 65.9704°c. Then at 0.1 seconds the temperature at T4 is 0.48°c, while at 10 seconds 19.5436°c. The conclusion is in the separator of the two-chamber thermos there is significant heat flow from the side of the first tube to the other side.
Menentukan nilai Energi Stacking Fault Paduan Baja Mangan Fe-Mn-C-Cr Menggunakan Persamaan Termodinamika Wahyudi, Haris; Pratiwi, Swandya Eka; Alva, Sagir; Subekti, Subekti
ROTASI Vol 27, No 2 (2025): VOLUME 27, NOMOR 2, JULI 2025
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.27.2.77-83

Abstract

Deformasi plastis pada baja austenit terjadi melalui salah satu dari tiga mekanisme deformasi yaitu transformasi martensit, dislokasi dan twinning. Perilaku plastisitas baja paduan terkait erat dengan energi stacking fault (SFE) fasa austenit.  Perhitungan nilai SFE secara langsung bisa dilakukan menggunakan Transmission Electron Microscopy (TEM). Akan tetapi, metode TEM perlu tahapan panjang, mahal, dan tidak mudah. Oleh karena itu, perhitungan berdasarkan model termodinamika menjadi alternatif cara yang digunakan untuk menghitung SFE pada baja Fe-Mn-Si dan Fe-Mn-C. Tujuan dari penelitian ini adalah untuk mendapatkan nilai SFE berdasarkan persamaan termodinamik untuk paduan baja mangan Fe-Mn-C-Cr. Metode yang digunakan yaitu studi literatur untuk mendapatkan parameter setiap unsur penyusun baja mangan antara lain Fe, Mn, C, Cr, dan Si. Nilai SFE dari persamaan termodinamika akan dibandingkan dengan persamaan empiris yang sudah diusukan oleh beberapa peneliti. Selain itu, nilai SFE akan dibandingkan nilainya dari database yang diperoleh dari eksperimen misal melalui TEM dan XRD. Nilai SFE dari hasil perhitungan menggunakan persamaan termodinamika diperoleh nilai 24±10 mJ/m2. Nilai SFE hasil perhitungan persamaan empiris menunjukkan nilai yang bervariasi dengan nilai terkecil 46,77 mJ/m2 dan terbesar adalah 510,16 mJ/m2. Nilai SFE hasil perhitungan persamaan termodinamika memiliki nilai mendekati nilai SFE di literatur yaitu 21 mJ/m2. Hasil ini membuktikan bahwa perhitungan nilai SFE menggunakan persamaan termodinamika lebih akurat dengan mempertimbangkan unsur penyusunnya.
Experimental Investigation of the Corrosion Rate of Factory-Original Motorcycle Exhausts in NaCl Solution and Natural Seawater Fadhilla, Eky Nur; Alva, Sagir
Jurnal Teknik Mesin (Journal Of Mechanical Engineering) Vol 14, No 3 (2025)
Publisher : Universitas Mercu Buana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22441/jtm.v14i3.36552

Abstract

Abstract-- Corrosion is a significant factor that decreases the performance and service life of motorcycle components, especially exhaust pipes that are directly exposed to the environment. This study aims to analyze and compare the corrosion rate of factory-made motorcycle exhausts when exposed to two corrosive media: a 3.5 wt% sodium chloride (NaCl) solution and natural seawater. An immersion test was conducted under laboratory conditions for seven days (168 h) using eight AISI 1010 coupons (2 × 2 cm). Four specimens were immersed in seawater, and four in 3.5 % NaCl. After pickling, each coupon was weighed, immersed, cleaned, and re-weighed. Mass loss was converted to a corrosion rate using the gravimetric method and expressed in millimeters per year (mm· year¹). The average corrosion rate in seawater was 4,121.9 mm/year, whereas in 3.5% NaCl it was 71.7 mm/year. The significantly higher rate in seawater is attributed to additional ions, such as magnesium, calcium, and sulfate, that accelerate electrochemical reactions. These findings underscore the importance of adequate surface protection for exhaust pipes, particularly for motorcycles operating in coastal or high-humidity environments, and serve as a basis for developing corrosion-resistant materials or coatings for automotive components.
Development of Solid State Reference Electrode Based on Polypyrrole (PPy) and Screen Printed Electrode (SPE) Alva, Sagir; Asadullah, Masud; Friliandita, Vivi; Khaerudini, Deni Shidqi
Journal of Carbazon Vol 1, No 2 (2023): December 2023
Publisher : Universitas Syiah Kuala

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24815/jocarbazon.v2i1.36417

Abstract

In this study, a Polypyrrole doped KCl/KCl saturated (PPy-Cl/KCl) reference electrode had been successfully developed. In this development process, the PPy-Cl/KCl reference electrode that had been provided consisted of two stages of refinement, specifically the PPy-Cl/KCl 1 reference electrode which became the PPy-Cl/KCl 2 reference electrode. Furthermore, the PPy-Cl/KCl 2 SRE was made into 3 types with cycle variations of 10, 15, and 20 cycles and the mV response value test and Scanning Electron Microscopy (SEM) test were carried out. Regarding the variation results, PPy-Cl/KCl 2 SRE was obtained with 15 cycles as the best PPy-Cl/KCl 2 reference electrode with mV value of 3.43 mV. Subsequently, the PPy-Cl/KCl 2 SRE with 15 cycles was involved in the characterization test using cyclic voltammetry (CV) testing, response testing vs Cl sensors and drift testing. In the CV testing, the PPy-Cl/KCl 2 SRE with 15 cycles indicated a voltammogram graphic pattern similar to the Ag/AgCl reference electrode as a commercial reference electrode. Moreover, in the response testing vs the Cl sensor, the PPy-Cl/KCl 2 SRE with 15 cycles provided a Nernstian number value of -54.5 mV/s with a testing range of 0.1-104 M, and in the PPy-Cl/SRE drift testing, KCl 2 with 15 cycles indicated fairly good stability, particularly with a drift value of 1 mV/minute which was achieved after the conditioning process after 3.5 minutes.
PENGARUH SUMBER ARUS LISTRIK TERHADAP NILAI TINGKAT SUARA KLAKSON BERDASARKAN STANDAR PENGUJIAN UN ECE R28 PART II Basyari, Aziz; Alva, Sagir
TURBO [Tulisan Riset Berbasis Online] Vol 13, No 1 (2024): TURBO : Jurnal Program Studi Teknik Mesin
Publisher : Universitas Muhammadiyah Metro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24127/trb.v13i1.3080

Abstract

The growth of motorized vehicles in Indonesia reached 4.1% with a total number of vehicles of 136,137,451. Vehicle units operated on the highway will cause an increase in noise on the highway caused by the operation of vehicle horns. The Indonesian government has regulated horn noise quality standards through Peraturan Pemerintah Nomor 55 Tahun 2012. Indonesia has agreed to the Asean Mutual Recognation Agreement (MRA) for automotive product standards in the Asean region referring to UN ECE where for horn testing it refers to the UN ECE R28 Part II standard. From testing the horn at durations of 1, 5, 10 and 15 seconds using a battery and an idle engine, there was no significant difference in the resulting horn sound level. This research aims to ensure the source of electric current when testing the horn so that the test can run more effectively and efficiently by establishing in the operational standards the UN ECE R 28 Part II test procedure using a battery only
Decrease Levels of Chromium, Copper, and Nickel in Liquid Waste of The Electroplating Laboratory of Medan Polytechnic with Electrocoagulation Method Alva, Sagir
Journal of Chemical Natural Resources Vol. 3 No. 2 (2021): Journal of Chemical Natural Resources
Publisher : Talenta Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (421.69 KB) | DOI: 10.32734/jcnar.v3i2.9346

Abstract

The liquid waste contained several metals such as Cr, Cu, and Ni in concentrations of 64 mg / L, 252 mg / L, and 125 mg / L, which may cause environmental pollution. The process of coating metal has resulted in heavy metal waste. The electrocoagulation process is a combination between electrochemical processes and coagulation-flocculation processes. This research aims to use the electrocoagulation method as an alternative for treating wastewater containing heavy metals in particular. The results showed a decreasing trend of percentage in metal content with decreased levels of 99.931%, 99.837%, and 99.994% for Cr, Cu, and Ni, respectively.
Determination of Potassium in Empty Bunches Palm Oil (Elaeis guineensis Jacq.) Using Flame Photometry Method Alva, Sagir
Journal of Chemical Natural Resources Vol. 3 No. 2 (2021): Journal of Chemical Natural Resources
Publisher : Talenta Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (326.621 KB) | DOI: 10.32734/jcnar.v3i2.9348

Abstract

Research on the determination of potassium in empty bunches palm oil have been done with the flame photometry method. The samples were taken randomly from five areas in Northen Sumatera with various heights in the range of < 25- 400 m above sea level. The first sampling was of Datuk Bandar district at Tanjung Balai < 25 m, Meranti district at Kisaran 50 to 100 m, Bosar Maligas district at Simalungun 150-200 m, Simarimbun district at Pematang Siantar 250 to 300 m, and the last Sari Matondang district at Sidamanik 350-400 m. The sample was digested using concentrated nitric aid and 30% hydrogen peroxide then heated with the addition of nitric acid concentrated. Potassium content was measured with a flame photometer at specific 767.5 nm by using calibration methods. The result obtained that potassium contents in the samples were 11.83%; 17.56%; 21.89%; 24.68%, and 25.14% for Tanjung Balai, Kisaran, Simalungun, Pematang Siantar, and Sidamanik respectively. The data obtained showed the higher area of the sea, the lower the temperature so the content of potassium increased in the palm oil empty bunches.
Determination of Level of Ag, Cu, and Fe in the Mineral Rock Coming from Jambu Dolok Hamlet Toba Samosir District Alva, Sagir
Journal of Chemical Natural Resources Vol. 3 No. 2 (2021): Journal of Chemical Natural Resources
Publisher : Talenta Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32734/jcnar.v3i2.9355

Abstract

A study on the determination of Ag, Cu, and Fe contents in mineral rocks has been conducted. The sample was randomly taken from the surface of the hill at Dusun Jambu Dolok Kabupaten Toba Samosir. Ovens destroyed the sample at 900°C. For the determination of Ag and Cu, the sample was dissolved by using concentrated HNO3. For the determination of Fe, it was dissolved by using concentrated HNO3 and concentrated HCl. The determination of Ag, Cu, and Fe was carried out using Atomic Absorption Spectrophotometer. The wavelength is 328.1 nm for Ag, 324.7 nm for Cu, and 248.3 nm for Fe. The results obtained show that the content of Ag, Cu, and Fe in the sample are 2.1590 mg/Kg, 21,311.4754 mg/Kg, and 150,000.0000 mg/Kg, respectively
Evaluating Vegetable Oils as Eco-Friendly Alternatives in Metal Heat Treatment : Review sukendar, Sukendar; Alva, Sagir; Ginting, Dianta
Jurnal Teknik Mesin (Journal Of Mechanical Engineering) Vol 15, No 01 (2026)
Publisher : Universitas Mercu Buana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22441/jtm.v15i01.37136

Abstract

Recent research on sustainable heat-treatment processes highlights the strong potential of vegetable oils as environmentally benign quenching media. This review integrates thermo-physical characteristics, cooling behavior, and mechanical performance reported in key studies from 2010–2024. Vegetable oils demonstrate higher quenching severity (H-value 0.17–0.21) than mineral oils (0.11–0.14), supported by stable viscosity ranges (20.78–110.35 cSt at 40°C; 6.9–33.65 cSt at 100°C) and superior thermal conductivity (0.131–0.182 W/m°C) relative to SAE40 (0.145 W/m°C). Their mechanical performance is consistently favorable: palm kernel oil yields hardness up to 40.85 HRC, cottonseed oil ~33.25 HRC, and groundnut oil produces ~173.8 HV with yield strength reaching 805 MPa. Neem seed oil exhibits exceptional hardness (68.7 HRA) and tensile strength (2122 MPa), while marula oil significantly enhances the hardness and tensile strength of medium-carbon steels. Soybean, sunflower, and canola oils applied to AISI 1045 steel deliver hardness levels of 41–50 HRC. Impact toughness also improves, with neem oil reaching 15 J and additive-modified quenchants containing 5% metal salts achieving up to 131 J. Antioxidant-fortified oils (Irganox L109, TBHQ, Propyl Gallate) further improve oxidation resistance without impairing cooling performance. Overall, properly stabilized vegetable oils represent robust, efficient, and environmentally responsible quenching alternatives for the heat treatment of low- and medium-carbon steels.
Effect of Coconut Fiber and Coconut Shell Charcoal Composition on the Properties of PVC-Reinforced Composite Brake Pads Aap Pandriana; Kurniawan Kurniawan; Sagir Alva
International Journal of Innovation in Mechanical Engineering and Advanced Materials Vol. 7 No. 1 (2025)
Publisher : Universitas Mercu Buana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22441/ijimeam.v7i1.31092

Abstract

The increasing concern over the health hazards associated with asbestos-based brake pads has driven the development of eco-friendly alternatives using natural fiber-reinforced composites. This study aims to fabricate and evaluate a sustainable brake pad material using coconut fiber as reinforcement, coconut shell charcoal powder as filler, and polyvinyl chloride (PVC) as the matrix. The composite was manufactured using the hot press method at a temperature of 180°C and a pressure of 7 MPa, conditions selected to optimize resin curing and interfacial bonding. A key focus of this research was to investigate the effect of solvent volume (cyclohexanone) used in the PVC resin preparation on the mechanical properties of the resulting composites. Three composite formulations were prepared with a constant composition of 70% coconut fiber, 5% charcoal powder, and 25% PVC resin, but with varying amounts of cyclohexanone solvent (200 mL, 150 mL, and 100 mL). The results revealed that reducing solvent content led to higher resin viscosity, which improved matrix–fiber bonding and increased both tensile strength and surface hardness. The optimal formulation—PVC Resin 3 with 100 mL of solvent—achieved a maximum tensile strength of 7.7 MPa and Shore D hardness of 72.2 HD, both of which meet the SAE J661-1997 standards for brake pad materials. This study confirms that solvent content is a critical factor influencing the density, strength, and durability of the composite. The findings support the feasibility of utilizing coconut-based agricultural waste in producing environmentally friendly brake pads with adequate mechanical performance.
Co-Authors Aap Pandriana Adelfy Dara Arianti Agnes Hanna Patty, Armin Naibaho, Singgih Fitra Utama, Ahmad Ariri Ahmad Kamal Arifin Aiman Sajidah Abd Aziz Aiman Sajidah binti Abdul Aziz Albert Phak Jie Wong Alfian Noviyanto Ali Rinaldi Andi Firdaus Sudarma Arianti, Adelfy Dara Arifin, Ahmad Kamal Ariri, Ahmad Asadullah, Mas'ud Asadullah, Masud Asep Setia Kristanto Baihaqi Baihaqi Basyari, Aziz Binawati Ginting Dafit Feriyanto Dayanti, Meri Deni Shidqi Khaerudini Dianta Ginting Edy Herianto Majlan Eka Safitri Eka Safitri Elin Yusibani Elly Sufriadi Fadhilla, Eky Nur Fadilah, Arif Fidi Fidi Fidi, Fidi Fitri Dara Fonna, Syafrizal Friliandita, Vivi Hadi Pranoto Hasbullah, Siti Aishah I Gusti Ayu Arwati Ibdal Satar Iqhrammullah, Muhammad Julinawati Julinawati Julinawati, Julinawati KHAIRI SUHUD Khairi Suhud Kurniawan Kurniawan Kurniawan Kurniawan Leni Heliawati Marysca Shintya Dewi Mas&#039;ud Asadullah Mohd Ismahadi bin Syono Muhammad Farhan Muhammad Isa Mustanir Mustanir Nurul Islami, Nurul Pandriana, Aap Popy Yuliarty Pudjiwati, Sri Resista Vikaliana Resmi Bestari Muin Rinaldi, Ali Rini Anggraini Robi Suherman Rohadi Satrio Budi Utomo Siti Aishah Hasbullah Subekti Subekti Suhud, Khairi Sukendar Sukendar Sukoma, Sukoma Sundari, Rita Supaat Zakaria Surbakti, Muhammad Syukri Suyadi, Yadi Swandya Eka Pratiwi Syafrizal Fonna Tarigan, Kontan Teddy Kurniawan Thasyah Pitanova Vivi Friliandita Wahyu Irwansyah Wahyudi, Haris Wan Adil bin Wan Jamil Wan Adil Wan Jamil Yeyen Maryani Zakaria Zakaria Zulnazri, Z