Articles
<![CDATA[Pengaruh Waktu Pencelupan Proses Electroless Plating Terhadap Pembentukan Lapisan Tembaga Antibakteri ]]>
<![CDATA[Pratesa, Yudha]]>;
<![CDATA[Noviardi, Luthfi]]>;
<![CDATA[Fadlilah, Muhammad]]>;
<![CDATA[Iqbal, Adimas Habib]]>;
<![CDATA[Rizkia, Vika]]>
<![CDATA[ Jurnal Kimia dan Kemasan Vol. 40 No. 1 April 2018 ]]>
Publisher : <![CDATA[Balai Besar Kimia dan Kemasan ]]>
Show Abstract
|
Download Original
|
Original Source
|
Check in Google Scholar
|
Full PDF (644.902 KB)
|
DOI: 10.24817/jkk.v40i1.3598
<![CDATA[Penyebaran penyakit oleh bakteri sangat rentan menjadi wabah di rumah sakit dan fasilitas umum melalui kontak secara langsung dan tidak langsung. Kontak secara tidak langsung terjadi  melalui alat perantara seperti jarum suntik, pakaian hingga gagang pintu. Salah satu bagian yang paling sering disentuh orang adalah gagang pintu dan kusen. Saat ini, banyak kusen yang dibuat dari bahan dasar logam aluminium karena harga yang murah, tahan korosi dan ringan. Kusen aluminium umumnya diproses anodisasi untuk memberikan efek warna karena kesukarannya jika dicat secara langsung. Produk anodisasi umumnya berstruktur pori sehingga dapat menjadi tempat ideal tumbuh dan berkoloni bakteri dengan mudah. Pada penelitian dilakukan pembuatan lapisan tembaga yang menutup pori dan mampu memberikan efek racun pada bakteri Escherichia Coli penyebab berbagai macam penyakit. Hasil dari penelitian ini menunjukkan, waktu electroless plating optimal selama 26 menit yaitu ketebalan antara 8-24 µm. Tembaga berhasil melapisi permukaan material secara merata. Hasil pengujian antibakteri dengan Kirby test menunjukan hasil plating memiliki kemampuan untuk mencegah pertumbuhan bakteri. Hasil uji ketahanan lapisan terhadap cuaca menggunakan saltspray menunjukan pelapisan selama 26 menit memberikan efek yang terbaik. ]]>
<![CDATA[Role of Flow Simulation as a Tools for Failure Analysis Induced by Sulphate-Reducing Bacterial ]]>
<![CDATA[Yudha Pratesa]]>;
<![CDATA[Badrul Munir]]>
<![CDATA[ EPI International Journal of Engineering Vol 1 No 1 (2018): Volume 1 Number 1, February 2018 ]]>
Publisher : <![CDATA[Center of Techonolgy (COT), Engineering Faculty, Hasanuddin University ]]>
Show Abstract
|
Download Original
|
Original Source
|
Check in Google Scholar
<![CDATA[Sulphate Reducing Bacterials (SRB) is one of the challanging problem in oil and gas. It could attack the metals to form a pit. The SRB ussually left a colony as the indication of corrosion attack. One of the main problem to prevent the corrosion attack is the ablitity to mapping the possibility of attacking area. However, this study offer a method to simulate the bacterial growth area based on the differential flow rate in the pipe. The flow simulation showed the ability to be used as the analytical tool for the bacterial growth mappings. Laboratory testing was also conducted for confirmation of the SRB presence in the system]]>
<![CDATA[EFFECT OF H2O2 AND MnO2 AS OXIDATORS OF GOLD AND COPPER LEACH PROCESSES FROM PRINTED CIRCUIT BOARDS ]]>
<![CDATA[Yudha Pratesa]]>;
<![CDATA[Aji Wibisono]]>;
<![CDATA[Wahyuaji Narottama Putra]]>;
<![CDATA[Yunita Sadeli]]>;
<![CDATA[A. Zakiyuddin]]>;
<![CDATA[Sri Harjanto]]>
<![CDATA[ Jurnal Sains Materi Indonesia Vol 20, No 3: APRIL 2019 ]]>
Publisher : <![CDATA[Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency ]]>
Show Abstract
|
Download Original
|
Original Source
|
Check in Google Scholar
|
Full PDF (794.453 KB)
|
DOI: 10.17146/jsmi.2019.20.3.4710
<![CDATA[In general, electronic waste management in the form 2 of printed circuit boards (printed circuit boards/PCBs) is carried out by the process of removing components and taking precious metals that are easily recycled. However, in Indonesia, the recycling process for extracting precious metals has not been much processed, even though they contain precious metals such as copper and gold. This research was conducted to find a more economical and environmentally friendly treatment process by using an oxidizer of Hydrogen Peroxide (H2O2) and Manganese Oxide (MnO2) and reducing the level of HCl used. Observation of metal leaching results using Atomic Adsroption Spectroscopy (AAS) showed the value of recovery (recovery) of gold and copper reached 59.1% and 59.8% for 0.5M HCl + 2.5% H2O2. However, the recovery value of copper has reached its optimum point at the addition of 1.5% H2O2. The use of 3% & 5% MnO2 results in recovery values of 12% and 24% for gold and copper. Observation of the cross section shows the dissolution of the copper metal from the PCB and accompanied by a change in the color of the solution from clear to green, the more concentrated the more the amount of dissolved copper metal shows the characteristic of CuCl solution. The results of the comparison of the two types of oxidizers show that H2O2 is better than MnO2 in producing higher Cu and Au metals more than 3 times.]]>
<![CDATA[Studi Pemanfaatan Estrak Daun Pegagan untuk Inhibitor Korosi Ramah Lingkungan untuk Material API 5CT J55 di Lingkungan Air Formasi ]]>
<![CDATA[Yudha Pratesa]]>;
<![CDATA[Andika Purnawidhi]]>;
<![CDATA[Nuringtyas Rahwinarni]]>
<![CDATA[ Jurnal Teknik Mesin Vol 7, No 1 (2018) ]]>
Publisher : <![CDATA[Universitas Mercu Buana ]]>
Show Abstract
|
Download Original
|
Original Source
|
Check in Google Scholar
|
DOI: 10.22441/jtm.v6i4.2178
<![CDATA[Daun Pegagan (Centella asiatica) pada awalnya dianggap sebagai tanaman pengganggu dan tidak bernilai ekonomis. Namun, hasil beberapa penelitian menunjukan manfaat daun ini sebagai obat karena memiliki kandungan fenolik dan anti oksidan. Karena bersifat anti oksidan, daun pegagan dinilai memiliki kemampuan untuk bekerja sebagai inhibitor korosi ramah lingkungan. Studi ini akan menguji kemampuan ekstrak Daun Pegagan sebagai inhibitor untuk baja API 5CT J-55 di lingkungan air formasi menggunakan pengujian polarisasi tafel, kehilangan berat (weigth loss) dan Fourier Transform Infrared Radiation (FTIR). Senyawa aktif antioksidan yang berperan untuk menginhibisi korosi akan diinvestigasi melalui pengujian FTIR dengan melihat potensi gugus yang terbentuk. Variabel yang digunakan adalah konsentrasi inhibitor, yaitu 0 ppm, 100 ppm, 250 ppm, 500 ppm, dan 1000 ppm. Ekstrak daun pegagan yang mempunyai gugus fenolik merupakan inhibitor jenis campuran, dan dominan anodik. Efisiensi inhibisi paling tinggi didapatkan dengan konsentrasi 250 ppm. Inhibitor ekstrak daun pegagan dapat digunakan sebagai alternative inhibitor ramah lingkungan untuk baja J55 pada lingkungan air formasi]]>
<![CDATA[Pengaruh kadar karbon pada material logam mampu luruh Fe-35Mn-C hasil metalurgi serbuk dengan kalium karbonat sebagai agent pembuat foam ]]>
<![CDATA[Pratesa, Yudha]]>;
<![CDATA[Setyaningrum]]>
<![CDATA[ Recent in Engineering Science and Technology Vol. 2 No. 03 (2024): RiESTech Volume 02 No. 03 Years 2024 ]]>
Publisher : <![CDATA[MBI ]]>
Show Abstract
|
Download Original
|
Original Source
|
Check in Google Scholar
|
DOI: 10.59511/riestech.v2i03.73
<![CDATA[: A Fe-35Mn-1C alloy with a foam structure, incorporating 5% potassium carbonate (K2CO3), was successfully synthesized, demonstrating an austenite phase and an acceptable degradation rate for an implant candidate. However, excessive carbon content led to the formation of a graphite phase and increasing hardness. To address this, variations in lower carbon composition (0% and 0.5%) were explored to enhance mechanical properties and achieve a fully austenite phase with non-magnetic properties. Mechanical alloying of the powder materials was performed using the rotary mixing method and was followed by sintering process in argon atmopher. The sintered samples underwent comprehensive characterization, including physical, chemical, mechanical properties, and degradation behavior. The Fe-Mn-C biomaterial exhibited an austenite and manganese oxide phase with a favorable degradation rate. This study showed K2CO3 is not only as a foaming agent but also could contribute to carbon alloying into the Fe-Mn alloy system.]]>
<![CDATA[A New Approach to Risk Assessment Model and Management for Jetty Fuel Terminal Industrywide Using Risk Priority Number ]]>
<![CDATA[Silalahi, Yoseph Valentino]]>;
<![CDATA[Munir, Badrul]]>;
<![CDATA[Pratesa, Yudha]]>
<![CDATA[ Recent in Engineering Science and Technology Vol. 3 No. 01 (2025): RiESTech Volume 03 No. 01 Years 2025 ]]>
Publisher : <![CDATA[MBI ]]>
Show Abstract
|
Download Original
|
Original Source
|
Check in Google Scholar
|
DOI: 10.59511/riestech.v3i01.92
<![CDATA[Jetty is an essential part of a fuel terminal and oil distribution process in terms of loading and unloading oil from and to tanker. Jetty has been widely used in fuel supply point facilities in archipelago countries like Indonesia. The increase in the importance given to maritime transportation has not only resulted in the development of the structure of safety issues but has also led to new investigations into the design of ships, the configuration of ports, and the operations conducted, all of which are essential components. However, it is not possible to ignore the risk inherent in jetty fuel terminal operations. Most of the reseach have pre-dominantly focused on the operation and impact of ship maneuvers and ship operations. But focusing on the jetty fuel risk itself is also very important as a whole part of reliability of a fuel receiving facility. FMEA is frequently used as a risk analysis method in determining risks arising from oil and gas sector. Each category of Severity, Occurance, and Detection from each risk factor can be rated to obtained the Risk Priority Number value. Mooring facilities assessment furthermore provides the implementation of assessment (grading) of operational suitability of jetties, based on the results of a visual assessment and special inspections. This paper aims to identify the risk associated with and to analyze these risk using Risk Priority Number ranking.]]>
<![CDATA[Wire Rope Sling Failure Analysis: Technical Root Causes, Investigation Methodology Critique, and Lessons for Lifting Safety and Organizational Learning ]]>
<![CDATA[Zaky, Ahmad]]>;
<![CDATA[Pratesa, Yudha]]>;
<![CDATA[Mudaryoto, Johny Wahyuadi]]>
<![CDATA[ Recent in Engineering Science and Technology Vol. 3 No. 03 (2025): RiESTech Volume 03 No. 03 Years 2025 ]]>
Publisher : <![CDATA[MBI ]]>
Show Abstract
|
Download Original
|
Original Source
|
Check in Google Scholar
|
DOI: 10.59511/riestech.v3i3.111
<![CDATA[Wire rope slings are critical in heavy lifting operations, yet their failure remains a persistent safety concern. This paper presents a case study of a catastrophic sling rupture that occurred during a heavy lifting trial, despite the lift being within its rated capacity. A multi-faceted failure analysis identified hidden corrosion fatigue at the sling’s ferrule and an unanticipated extreme overload condition as the primary technical root causes. Procedural and organizational factors—including inadequate risk assessment, deviation from critical lift protocols, and failure to act on prior lessons—also contributed to the incident. The contractor’s investigation is critically reviewed against best-practice Root Cause Analysis guidelines, highlighting both strengths and gaps in its methodology. Key lessons to improve lifting safety are discussed, such as implementing rigorous inspection and retirement criteria for aging slings and ensuring comprehensive lift planning. Overall, the case underscores the importance of robust investigation practices and effective organizational learning to prevent similar failures in the future.]]>
<![CDATA[Pemanfaatan Campuran Myrmecodia Pendans dan Piper Crocatum Sebagai Green Corrosion Inhibitor pada Inhibitor Kimia Jenis Koktail untuk Proteksi Korosi Baja API 5L Grade B dalam Larutan NaCl 3,5% ]]>
<![CDATA[Rani Kusumawardani]]>;
<![CDATA[Agus Budiono]]>;
<![CDATA[Johny Wahyuadi Soedarsono]]>;
<![CDATA[Yudha Pratesa]]>
<![CDATA[ Recent in Engineering Science and Technology Vol. 3 No. 03 (2025): RiESTech Volume 03 No. 03 Years 2025 ]]>
Publisher : <![CDATA[MBI ]]>
Show Abstract
|
Download Original
|
Original Source
|
Check in Google Scholar
|
DOI: 10.59511/riestech.v3i3.112
<![CDATA[Method to prevent the corrosion during pipeline hydrotest using seawater is generally by the addition of inorganic inhibitor containing corrosion inhibitor agent, oxygen scavenger and biocide, so that require to find out the alternative eco-friendly materials with better performance. The main objective of this study is to investigate the efficiency of the use of mixture of extract of Myrmecodia pendans and Piper crocatum as an alternative of eco-friendly inhibitor for reducing the use of inorganic inhibitors for corrosion protection of steel material API 5L Grade B in 3.5% NaCl. The corrosion inhibition ability of natural ingredient extraction are investigated by using tafel polarization test and EIS and verified by weight loss test. The content of the active compounds in natural ingredient extraction along with adsorption compound on metal surfaces and inhibition mechanism are investigated by EIS, FTIR and adsorption isotherm model. In the mixed green inhibitor concentration of 2 ml Myrmecodia pendans and 1 ml Piper crocatum is resulted in approximately 73.66% inhibitor efficiency while concentration of 1 ml chemical cocktail and 2 ml green inhibitor are significantly reduce the corrosion rate from 0.42 mm/year to be 0.03 mm/year with approximately 93.15% inhibitor efficiency. The green inhibitor affected the cathodic as well as the anodic polarization curves which were known as mixed corrosion inhibitor type. The adsorption of compounds contained in the Myrmecodia pendans and Piper crocatum on a metal surface are occur spontaneously follows the Langmuir adsorption isotherm.]]>
<![CDATA[Study of the Effect of Volume of Moringa Leaves and Purple Sweet Potato Extracts as a Green Corrosion Inhibitor on the Corrosion of API 5L Steel Metals in 0.2 M HCl Environments ]]>
<![CDATA[Kezia]]>;
<![CDATA[Pratesa, Yudha]]>;
<![CDATA[Pertama, Tio Angger]]>;
<![CDATA[Soedarsono, Johny Wahyuadi]]>
<![CDATA[ Recent in Engineering Science and Technology Vol. 3 No. 04 (2025): RiESTech Volume 03 No. 04 Years 2025 ]]>
Publisher : <![CDATA[MBI ]]>
Show Abstract
|
Download Original
|
Original Source
|
Check in Google Scholar
|
DOI: 10.59511/riestech.v3i04.120
<![CDATA[This study aimed to investigate the corrosion inhibition mechanism of moringa leaves extract (Moringa oleifera) and purple sweet potato extract (Ipomoea batatas) extract as environmentally friendly inhibitors for low carbon API 5L steel in a 0.2 M HCl solution. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests were conducted with varying concentrations and combinations of the two inhibitors to evaluate their corrosion inhibition performance. The results indicated that both inhibitors individually function effectively as green corrosion inhibitors. However, their combination did not offer adequate protection for API 5L steel in a 0.2 M HCl environment. FTIR analysis of the inhibitors confirmed the presence of flavonoid compounds in both extracts. Potentiodynamic polarization tests showed that increasing the concentration of moringa leaves extract resulted in a decrease in the corrosion rate and an increase in %IE, with the highest efficiency reaching 73.08%. Similarly, an increase in the volume of purple sweet potato extract also resulted in a reduced corrosion rate, with a maximum inhibition efficiency of 65.31%. However, the combination of both inhibitors led to an increase in the corrosion rate. The results of the EIS test demonstrated that both inhibitors protect the metal by forming a protective film layer on its surface. The adsorption behavior of the inhibitors corresponds to a physical adsorption process and aligns with the Langmuir adsorption isotherm model.]]>
<![CDATA[Assessment of H2S-Induced Cracking Susceptibility in Steam Line Pipes and Weld Zones During Geothermal Well Construction ]]>
<![CDATA[Pragitta, Riene Kaelamanda]]>;
<![CDATA[Pratesa, Yudha]]>
<![CDATA[ Journal of Materials Exploration and Findings Vol. 4, No. 1 ]]>
Publisher : <![CDATA[UI Scholars Hub ]]>
Show Abstract
|
Download Original
|
Original Source
|
Check in Google Scholar
<![CDATA[The susceptibility of steam line pipes, especially in the HAZ (heat-affected zone) and weldment areas, to hydrogen sulfide in the geothermal industry is crucial to understand from the early stages, particularly during construction. The combination of tensile stress from residual stresses after welding and metallurgical phase transformation makes the joint areas vulnerable to sulfide stress cracking. This condition becomes even more extreme when the equipment operates during the well stimulation phase. This research assesses the severity of H₂S-induced cracking using NACE MR0175 and ISO 15156-1 standards, focusing on the effects of pH and partial pressure of H₂S (pH₂S). The findings aim to provide insights into critical factors influencing H₂S cracking susceptibility and to enhance material integrity in geothermal systems. The result shows that while A106 Gr B steel generally meets sour service requirements, certain nodes within the geothermal facility exhibit a moderate risk of cracking under transient conditions. These results emphasize the importance of controlling fluid composition and implementing proper welding procedures to mitigate sulfide stress cracking (SSC).]]>
