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All Journal Rekayasa: Jurnal Penerapan Teknologi dan Pembelajaran ROTOR: JURNAL ILMIAH TEKNIK MESIN Jurnal METTEK (Jurnal Ilmiah Nasional Dalam Bidang Ilmu Teknik Mesin) Jurnal Akuakultur Sungai dan Danau JURNAL POLI-TEKNOLOGI Journal of Materials Exploration and Findings Jurnal Polimesin Recent in Engineering Science and Technology
Ahmad Maksum
Politeknik Negeri Jakarta
Aerospace Engineering Automotive Engineering Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Electrical & Electronics Engineering Energy Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering Transportation Other

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Modification Monitoring of Combustion Chamber Temperature and Pressure on Diesel Engines Juna, Haidir; Nufus, Tatun Hayatun; Maksum, Ahmad
Rekayasa : Jurnal Penerapan Teknologi dan Pembelajaran Vol 19, No 1 (2021): July 2021
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/rekayasa.v19i1.30371

Abstract

Along with the development of technology in the industry, especially automotive, professional workers who are reliable and master their fields in theory and practice are expected. Ideally, educational institutions such as polytechnics should provide adequate equipment and facilities to achieve learning objectives. A critical process in the combustion engine system is where a cycle of pressure and temperature changes at each piston stroke. Unfortunately, many students' understanding of the diesel engine cycle system still needs to be improved, even though the diesel engine cycle had been discussed in the engine system course or thermodynamics. Therefore, this study was intended to modify the Diesel Engine in the heavy equipment workshop to be used as a learning media for the combustion engine and thermodynamic, especially the diesel cycle. This research started with identifying and preparing to identify and to prepare equipment and materials, installing pressure and temperature sensors, controller installation, calibration, and final testing. The test results show the correspondence between the theoretical and experimental cycles, although a few typical differences usually occur between theoretical and practical in the field.
PEMANFAATAN SEKAM PADI BERAS HITAM SEBAGAI INHIBITOR KOROSI YANG RAMAH LINGKUNGAN Ahmad Maksum
Jurnal Poli-Teknologi Vol. 10 No. 3 (2011)
Publisher : Politeknik Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (389.095 KB) | DOI: 10.32722/pt.v10i3.64

Abstract

Currently, the use of chemical inhibitors has been limited because it can pollute the environment. In line with the concern for environmental health, this research studied the effectiveness of corrosion inhibition of mild steel in 1M HCl solution by extracts of black rice husk. Results obtained from the method of weight loss and potentiodynamic polarization shown that extracts of black rice husks act as mixed-inhibitor effectively in an acidic environment, where the cathodic inhibition effect is more dominant. Inhibition efficiency of black rice bran extracts was increased with increasing concentrations of inhibitors, and achieve optimum efficiency value of 91% with the addition of 2000ppm extract on day six. Keywords: Black Rice Husk, Corrosion inhibitors, Mild Steel, 1M HCl. ABSTRAK Saat ini, penggunaan inhibitor kimia telah dibatasi karena dapat mencemari lingkungan. Sejalan dengan kepedulian akan kesehatan lingkungan, penelitian ini mempelajari efektifitas penghambatan korosi mild steel dalam larutan 1M HCl oleh ekstrak sekam padi hitam. Hasil yang didapatkan dari metode weight loss dan potentiodynamic polarization menunjukkan bahwa ekstrak sekam beras hitam bertindak sebagai mixed-inhibitor dalam lingkungan asam secara efektif, dimana efek inhibisi katodiknya lebih dominan. Efisiensi penghambatan ekstrak sekam beras hitam ini meningkat dengan peningkatan konsentrasi inhibitor, dan mencapai nilai efisiensi optimumnya 91% dengan penambahan 2000ppm ekstrak pada hari ke enam. Kata kunci : Sekam Padi Beras Hitam, Inhibitor Korosi, Mild Steel, 1M HCl
Effect of Thiosulfate Concentration and Leaching Temperature in Ammoniacal Thiosulfate Leaching of Refractory Sulfide Gold Ore Rini Riastuti; Kautsar Muwahhid; Ahmad Maksum; Johny Wahyuadi Soedarsono; Mhd. Ibkar Yusran Asfar
Jurnal Mettek: Jurnal Ilmiah Nasional dalam Bidang Ilmu Teknik Mesin Vol 8 No 2 (2022)
Publisher : Program Studi Magister Teknik Mesin Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/METTEK.2022.v08.i02.p09

Abstract

Tiosulfat sebagai larutan pelindian emas pertama kali dipelajari pada tahun 1979 untuk menemukan alternatif larutan sianida dan merkuri yang banyak digunakan dalam industri ekstraksi emas meskipun berdampak negatif bagi lingkungan. Sampel bijih yang digunakan adalah bijih asli dari Bolaang Mongondow, Sulawesi Utara. Berdasarkan pengamatan Mikroskop Optik dan karakterisasi LIBS, terdapat senyawa pirit yang merupakan salah satu karakteristik bijih sulfida. Menurut fluoresensi sinar-X dan Inductively Coupled Plasma, bijih mengandung sekitar 14,62% ??Fe, 6,69% ??S, 0,15% Cu, dan 0,27 ppm Au. Penelitian ini bertujuan untuk mengetahui pengaruh konsentrasi tiosulfat dan temperatur pelindian pada pelindian tiosulfat amoniak bijih emas sulfida refraktori terhadap kelarutan emas. Penelitian ini dilakukan dengan metode leaching skala laboratorium. Hasil leaching kemudian diperiksa dengan Inductively Coupled Plasma (ICP). Konsentrasi tiosulfat (0,05M, 0,1M, dan 0,2M) dan pengaruh temperatur (25?C, 40?C, 60?C) dipelajari. Ekstraksi emas maksimum (62%) diperoleh dengan menggunakan konsentrasi tiosulfat 0,1M pada 40?C selama 2 jam dengan kepadatan pulp 20%. Kecepatan pengadukan dan pH larutan berair masing-masing adalah 400 rpm dan 10. Berdasarkan hasil tersebut dapat disimpulkan bahwa konsentrasi larutan tiosulfat dan temperatur pelindian akan mempengaruhi kelarutan emas. Thiosulfate as gold leach solution first studied in 1979 to found alternative of cyanide and mercury solution which are widely used in gold extraction industry although it’s negative impact for the environment. The ore sample is native ore from Bolaang Mongondow, North Sulawesi. According to Optical Microscope observation and LIBS characterization, there are pyrite compound which is one of the chacaracteristic of sulfide ore. According to X-ray fluorescence and Inductively Coupled Plasma, the ore contained about 14.62% Fe, 6.69% S, 0.15% Cu, and 0.27 ppm Au. This study aimed to determine the effect of thiosulfate concentration and leaching temperature in ammoniacal thiosulfate leaching of refractory gold sulfide ores on the solubility of gold. This research was conducted by laboratory scale of leaching method. The leaching result is then checked by Inductively Coupled Plasma (ICP). The concentration of thiosulfate (0.05M, 0.1M, and 0.2M) and the effect of temperature (250 C, 400 C, 600 C) were studied. Maximum gold extraction (62%) was obtained using 0.1M of thiosulfate concentrations at 400 C for 2 h with 20% of pulp density. Stirring speed and the pH of the aqueous solution were 400 rpm and 10, respectively. According to the results, it can be concluded that the concentration of Thiosulfate solution and leaching temperature will affect the dissolution of gold.
STUDY OF INFLUENCE TIME IN THE IMPROVEMENT OF NICKEL CONTENTS ON LIMONITE PROCESSING USING NAOH Rini Riastuti; Kautsar Muwahhid; Ahmad Maksum; Johny Wahyuadi Soedarsono; Mhd. Ibkar Yusran Asfar
ROTOR Vol 15 No 2 (2022)
Publisher : Jurusan Teknik Mesin Fakultas Teknik Universitas Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/rotor.v15i2.34326

Abstract

Logam nikel didominasi oleh bijih sulfida, namun 70% sumber nikel dunia adalah bijih laterit, yang hanya menyumbang 40% dari output nikel dunia. Menanggapi kenaikan permintaan dan penurunan deposit nikel sulfida, pemurnian nikel bijih laterit dan teknik produksi hidrometalurgi untuk bijih laterit semakin intensif. Silikon dapat diekstraksi dari bijih nikel laterit dengan NaOH. Berbagai penelitian menunjukkan bahwa metode ini dapat meningkatkan kandungan nikel dari residu pelindian, memungkinkan limbah sisa untuk digunakan kembali dan mengurangi dampak lingkungannya. Penelitian ini bertujuan untuk mengetahui apakah mekanisme pengendapan dapat secara efektif memisahkan nikel dan kobalt dari pengotor lainnya. Limonit dilindi menggunakan larutan NaOH dengan konsentrasi 60 g/L. Durasi pelindian bervariasi antara 30, 60, 90, dan 120 menit. Pengaruh NaOH sebagai larutan pelindian diselidiki dengan pengujian XRD dan AAS. Hasil dari analisis XRD menunjukkan proses pelindian menggunakan NaOH membentuk fasa nikel dan kobalt oksida dan hidroksida dari goetit dan NaOH, dengan fasa lain pada residu pelindian terbentuk seiring dengan bertambahnya waktu pelindian. Pengujian AAS menunjukkan nilai perolehan nikel negatif yang dapat dihasilkan oleh kontaminan pada sampel awal, pelarutan ion nikel, dan kopresipitasi, dimana ion nikel diserap ke dalam fase besi hidroksida. Selain itu, uji AAS juga menunjukkan nilai perolehan kembali kobalt pada waktu pelindian 30 menit adalah 1,41%, yang berarti bahwa waktu tersebut adalah waktu optimum untuk pelindian kobalt. Sedangkan waktu yang melebihi 30 menit dapat menurunkan kadar kobalt karena pengenceran ulang dan pengendapan bersama.
Utilization of Cellulose Symbiotic Culture of Bacteria and Yeast (SCOBY) with Sweet Tea Media as Methylene Blue and Brilliant Green Biosorbent Material Sigiro, Leonard Mateus; Maksum, Ahmad; Dhaneswara, Donanta
Journal of Materials Exploration and Findings Vol. 2, No. 1
Publisher : UI Scholars Hub

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

Abstract

The cellulose from Symbiotic Culture of Bacteria and Yeast (SCOBY) can be used as a biosorbent for dye adsorption, such as Methylene Blue and Brilliant Green. This study used sweet tea with a 6% of sugar concentration and 14 days of fermentation time to synthesize biosorbent material from SCOBY. The results from this synthesis are then characterized using FTIR, SEM, and BET. From the result of characterization, it was found that SCOBY has pores formed from cellulose. The results of the average pore size are 1.5976nm with a pore volume of 0.229cc/g, while the specific surface area is 143.244m2/g. The material that has been characterized is used to absorb the dye using Methylene Blue and Brilliant Green. The mass variation of absorbent is used in this study with variations of 0.5gr, 1gr, and 1.5gr and carried out to absorb the dye for three hours. The highest percentage of dye removal after three hours reached up to 100%, which proved that SCOBY is effective for dye removal.
Effect of Slope Chute Angle of HAP Magnetic Separator to the Acquisition of Nickel Matte from Undersized Product Resulted by Pierce Smith Converter Machine Indah Ciptasari, Nurhayati; Arya Parande, Egidius; Wahyuadi Soedarsono, Johny; Budi Prasetyo, Agus; Mayangsari, Wahyu; Miftahul Ulum, Reza; Maksum, Ahmad
Recent in Engineering Science and Technology Vol. 1 No. 03 (2023): RiESTech Volume 01 No. 03 Years 2023
Publisher : MBI

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.59511/riestech.v1i03.18

Abstract

The prototype of a magnetic separator was initiated and manufactured for handling undersized products of Pierce Smith Converter which has been channeled to a temporary shelter called a matte pond. It was dredged three to four times a year and it’s costly. This expenditure can be minimized by the manufacture of magnetic separators that are used to attract undersized nickel products. The manufacture of this prototype uses a scale of 1:20.000 for the volume of water and nickel matte, while for chute and magnetic drums with a scale of 1:4 from the conditions in the field. This research aims to determine whether magnetic separators are relevant for installation in the nickel processing industry, with the slope angle of the chute and magnetic power as the main parameters. Thus the matte pond can be minimized and undersized products can be directly processed and distributed to consumers. The material used in the manufacture of this prototype is aluminum sheet 1/16 which is rolled for magnetic drums, aluminum sheet 1/8 in for chute, copper wire 0.5 mm and mild steel, lathe for rods and axis, and bending for magnetic holders. The result of this magnetic separator prototype is 24.48% nickel can be attracted.
Efektivitas Ekstrak Daun Ubi Jalar (Ipomea batatas) Terhadap Tingkat Stres Induk Ikan Nila (Oreochromis niloticus) dalam Sistem Transportasi Nurussalam, Wildan; Maksum, Ahmad; Supriyono, Eddy; Mahmud, Moh Burhanuddin; Permatasari, Sheny
Jurnal Akuakultur Sungai dan Danau Vol 10, No 1 (2025): April
Publisher : Universitas Batangahari Jambi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33087/akuakultur.v10i1.249

Abstract

Broodstock transportation is a critical phase in aquaculture in Nile tilapia (Oreochromis niloticus), directly influencing brood quality and reproductive success. This study investigated the effectiveness of sweet potato leaf extract (Ipomoea batatas) at varying concentrations in a closed transport system to reduce stress and improve survival. A completely randomized design (CRD) with four treatments and three replications was employed: N1 (control, no extract), N2 (2 mL/L extract), N3 (4 mL/L extract), and N4 (6 mL/L extract). Parameters measured included survival rate (SR), daily growth rate (DGR), feed consumption (FC), water quality (temperature, pH, dissolved oxygen, ammonia, nitrite), and stress response via blood glucose levels. Results indicated that adding sweet potato leaf extract significantly influenced water quality, reduced stress, and improved fish survival. The 4 mL/L treatment (N3) yielded the best outcomes, with a 100% survival rate and the lowest blood glucose level (77.67 mg/dL), suggesting its potential as an effective natural antistress agent during broodstock transport.
The investigation of the properties of filaments fabricated from carbon biomass and LLDPE Pramono, Agus Edy; Patrick, Yohannes; Zuhri, Aminudin; Setiyadi, Iman; Maksum, Ahmad; Indayaningsih, Nanik; Subyakto, Subyakto
Jurnal Polimesin Vol 22, No 4 (2024): August
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v22i4.5084

Abstract

This study aims to develop composites using electrically conductive carbon and polymer polyethylene (LLDPE) to enhance electrical conductivity. Investigations have been conducted on the fabrication of electrically conductive composites and the modulus of elasticity through heat compaction using mixtures of carbon-LLDPE powders. Heat compaction is performed at temperatures ranging from 120°C to 150°C, with varying composition ratios of carbon-LLDPE, including 50:50, 60:40, and 70:30 % wt. Higher proportions of carbon and compaction temperatures are correlated with increased electrical conductivity. For instance, the C7-3LLDPE composite, compacted at 150°C, demonstrates the highest electrical current flow of 0.0018 A, whereas the C5-5LLDPE composite, compacted at 135°C, exhibits the lowest current flow at 0.0000638 A. Regarding the modulus of elasticity, the composition ratio of C7-3LLDPE, compacted at 120°C, achieves the highest value at 2686.43 [N/mm2 ]. Conversely, the composition ratio of C5-5LLDPE, compacted at 135°C, yields the lowest modulus of elasticity at 1530.94 [N/mm2 ]. Elasticity modulus testing follows the ASTM D638 standard, with a speed of 2 mm/min. It is observed that increasing the compaction temperature results in a decreased modulus of elasticity across all composition ratios. Furthermore, a higher carbon content within the composite corresponds to a higher modulus of elasticity, regardless of the compaction temperature.
Co-Authors Arya Parande, Egidius Budi Prasetyo, Agus Dhaneswara, Donanta Eddy Supriyono Indah Ciptasari, Nurhayati Johny Wahyuadi Soedarsono Juna, Haidir Kautsar Muwahhid Kautsar Muwahhid Mhd. Ibkar Yusran Asfar Miftahul Ulum, Reza Moh. Burhanuddin Mahmud Nanik Indayaningsih Patrick, Yohannes Permatasari, Sheny Pramono, Agus Edy Rini Riastuti, Rini Setiyadi, Iman Sigiro, Leonard Mateus Subyakto Subyakto Tatun Hayatun Nufus Wahyu Mayangsari Wildan Nurussalam Zuhri, Aminudin