Article Per Year (5 Year)
p-Index From 2019 - 2024
1.182
P-Index
This Author published in this journals
All Journal Jurnal POLIMESIN Jurnal Teknologi
Luthfi Luthfi
Politeknik Negeri Lhokseumawe
Automotive Engineering Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Electrical & Electronics Engineering Energy Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering

Published : 7 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 7 Documents
Search

 1 
The influence of height on the spreading distance of axisymmetric jets impinging on a rigid surface Luthfi Luthfi
Jurnal POLIMESIN Vol 20, No 1 (2022): February
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (503.631 KB) | DOI: 10.30811/jpl.v20i1.2437

Abstract

The influence of the domain height of negative buoyancy jets when impinging on a rigid surface has been investigated. The study was conducted numerically by applying the Computational Fluid Dynamics (CFD) method.  The numerical model consists of a set of Navier-Stokes equations together with an energy equation. The jet flow was modeled in a two-dimensional axisymmetric coordinate. The governing equations were solved in transient using the finite volume approach. The programming code for the numerical model was written in Fortran. The numerical simulations were run at Froude number Fr = 5.0; Reynolds number, Re = 200 and Prandtl number Pr = 7.0. The investigated parameter, the domain height was varied at around 8.8 ≤ H/X0 ≤ 10.2. The flow visualization created from simulation results has revealed the mystery behind the complex flow behavior in detail. Starting from the initial flow when the jet entered the domain to the complex flow pattern of the jet flow detaching from the top surface. Including when the downflow mixes with the upflow creating a recirculation area near the top surface and the bottom of the domain. The plot of the spreading distance over time shows that there is a maximum distance when the jet starts detaching from the top surface. Gradually, the distance decreases until reaching a fixed final distance when the jet flow reaches quasi-steady. The influence of the domain height that was investigated shows different flow patterns at different heights. The plot of final distances over the domain height shows that there is a nonlinear relationship. The regression equation created from the numerical data shows good agreement and accuracy.
Review Of Multicrystalline Silicon Wafer Solar Cell Processing Azwar Azwar; Luthfi Luthfi; Muhammad Muhammad
Jurnal POLIMESIN Vol 19, No 1 (2021): February
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (694.391 KB) | DOI: 10.30811/jpl.v19i1.2090

Abstract

The challenges for searching and utilizing  of new and sustainable energy sources especially solar cell electricity. The major obstacle of using solar cells for electricity generation has been a much higher price when compared to the price of electricity generated from the traditional sources. The photovoltaic industry needs to put an enormous pressure and optimization at every stage of the photovoltaic manufacturing chain of multicrystalline silicon wafer solar cell processing  in order to reduce cost.  Processing of multicrystalline silicon solar cells  is starting by silicon wafer preparation, etching and texturing,  saw damage etching, surface texturing, phosphor diffusion edge isolation, phosphor diffusion, edge isolation, silicon nitride deposition for antireflection coating, and metallization process that consist of screen printing ag front side, screen printing of al back side, drying and firing and formation al back surface contact.  Mechanical stability of silicon wafer became a serious issue due to reduction of wafer thickness, so probability for wafer to breakage is high; investigate the mechanism of wafer breakage is important to reduce breakage. The present of micro cracks reduces the mechanical strength of wafer significantly and wafer breakage will increase, because crack will start from the existing micro crack and that will propagate easier with presence of the stress. Mechanical stability is increase significantly after the etching process; on the other hand the screen printing process will reduce wafer strength.  Etching of saw damage, that is induced during wafer slicing, and metallization of the surfaces are 2 crucial processing steps in the manufacturing of mc-silicon solar cells
Investigation of the Mechanical Behavior of Laminated Composites Gypsum-Based Plastic Sack Waste Fiber Indra Mawardi; Samsul Bahri; Hamdani Nurdin; Irwin Syahri Cebro; Luthfi Luthfi; Zuhaimi Zuhaimi; Ismi Amalia
Jurnal POLIMESIN Vol 21, No 1 (2023): February
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v21i1.3275

Abstract

The existence of plastic waste, such as used plastic sacks in large quantities, is a crucial problem for the environment and health because of its very low biodegradability. Therefore, reusing plastic sack waste as reinforcement in gypsum composites is a major research issue. This study investigates the mechanical and physical properties of gypsum composites reinforced with fiber layers from plastic sack waste. Gypsum composites are produced using casting gypsum flour as the matrix and various fiber layers from plastic sack waste (1, 2, 3, 4) as reinforcement. Gypsum-based laminated composites were tested for density, flexural strength, and compression. The behavior of mechanical, physical, and damage properties is studied to see its suitability as a building material. The results showed that gypsum composites' density decreased with increasing sack fiber layers. The density of gypsum composites ranges from 1064-1199 kg/m3, with a maximum value in samples with 100% gypsum. The flexural strength of gypsum composites ranges from 2.21-4.10 MPa, and the compressive strength ranges from 3.5-6.66 MPa. Increasing the number of layers of plastic sack fibers reduces density, flexural strength, and compressive strength. However, all the mechanical properties of gypsum composites met the requirements of the EN 13279-2 standard. Failure of fiber delamination with the resulting matrix is the main cause of the decrease in mechanical strength
Gas Turbine Maintenance Optimizing using the Reliability-Centered Maintenance Method Darmein Darmein; Marzuki Marzuki; Zuhaimi Zuhaimi; Fauzi Fauzi; Nurlaili Nurlaili; Luthfi Luthfi
Jurnal POLIMESIN Vol 21, No 1 (2023): February
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v21i1.3281

Abstract

Gas Turbine is one of the important equipment in the production process in the oil and gas industry. This equipment is used as the prime mover of the compressor to the gas supply. The company has implemented preventive maintenance and condition monitoring in the context of gas turbine maintenance as well as scheduled shutdown every 52,000 hours of operation time. Along with efforts to increase production, the company's management policy has implemented a gas turbine maintenance efficiency program from 52,000 hours to 72,000 hours of operation. This policy is based on the consideration that productivity decreases over time and component replacement during MI (Major Inspection) and HGPI (Hot Gas Path inspection). This policy will certainly have an impact on the reliability, performance, and failure rate that will be experienced by gas turbines as well as their impact on maintenance costs. This study aims to recommend optimal maintenance strategies for gas turbines using the Reliability Centered Maintenance (RCM) method related to availability, reliability, maintainability, and maintenance costs. In this study, an analysis of the causes and effects of failure was carried out using the Failure Mode and Effect Analysis (FMEA) method, with the parameters of failure frequency and consequences of failure then analyzed using the RCM worksheet to determine an effective maintenance strategy.  The results of this study obtained maintenance strategy for Gas Turbine components which are Failure finding, Redesign on conditioning, and Schedule discard task. The components that are scheduled for repairs are compressors and turbines and components that receive a component replacement schedule are Air Inlet and Combustion. The application of the RCM method has been able to reduce maintenance costs by up to 30.678% along with reduced downtime rates, decreased failure rates and the number of MTTR hours
The Effect of Current Density on Mechanical Properties of Electroplated Thin Copper Foil Luthfi Luthfi; Yuniati Yuniati; Darmein Darmein; Sumardi Sumardi
Jurnal POLIMESIN Vol 21, No 1 (2023): February
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v21i1.3456

Abstract

Thin copper foils are commonly used in arts, crafts, and manufacturing industries. Although copper electroplating processes have been widely studied, most focused on either copper in bulk material form factor or copper in extremely thin film shape. Thin copper foils are considered neither bulk material nor thin film; thus, it is estimated that they will have unique properties. This study aims to investigate the mechanical properties of thin copper foils coated by electroplating processes. The investigations were conducted experimentally by performing electroplating at current densities of 2, 3, and 4 A/dm2. The copper foil specimen having a dimension of 10 mm wide, 0.2 mm thick, and 125 mm long were electroplated in a bath of copper sulfate, sulfate acid, chloride acid, and copper brightener mixtures for 60 minutes powered by a 30 A DC power supply. The hardness and tensile test diagrams were studied. The strain, yield stress, and ultimate tensile stress data extracted from the tensile test diagram were compared with other previous studies found in the literature and fitted with linear regression lines. The relationship of those parameters with current density has been successfully obtained. The hardness, strain, and yield stress of the electroplated copper foil increased with larger current densities used in the electroplating process except for the ultimate tensile stress, which was found to be slightly decreased with current densities. The optimum operating condition for obtaining the best results was found at a current density of 3 A/dm2.
Analisis Termal Stainless Steel Ice Cubes dengan Menggunakan Sensor Termokopel DS18B20 Berbasis Arduino Luthfi Luthfi
Jurnal Teknologi Vol 23, No 1 (2023): April 2023
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/teknologi.v23i1.3839

Abstract

Stainless ice cubes as reusable ice packs have recently become more popular for cooling food and beverages. Compared to ordinary water-based ice cubes, they will not alter the taste as they do not melt and mix with food/drink, and in the long run, they can save money as they can be reused. Due to little information on their technical performance in the literature, this study will investigate their thermal characteristics, especially when compared to water ice cubes and custom-made stainless ice cubes. A water-proved temperature measurement system consisting of 5 pieces of DS18B20 thermocouple sensor controlled by Arduino UNO DIP Microcontroller was built and tested for this purpose. The tests were conducted on three separate drinking glasses containing three different ice cubes. The measurement system successfully revealed the temperature evolution of the three types of ice cubes. Water ice cubes still produced the coldest water temperature, although the commercial ice cubes purchased from the online market are not too far behind. Custom-made ice cubes containing no Phase Change Material (PCM) substance inside them do not significantly cool the water. 
Thermal analysis and thermography observation of stainless-steel ice cubes Luthfi Luthfi; Azhar Azhar; Zuhaimi Zuhaimi; Syamsuar Syamsuar; Sumardi Sumardi
Jurnal POLIMESIN Vol 21, No 4 (2023): August
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v21i4.3985

Abstract

Alternative products for water ice cubes have long been sought due to the spread of waterborne diseases and microplastic contamination, as they are often made from unhygienic water sources. Recently, stainless-steel ice cubes have been considered as one of the best alternatives, and they have been very popular in marketplaces, although very few studies found in the literature that have investigated their potential in replacing water ice cubes. In this study, the thermal performance of stainless-steel ice cubes will be explored experimentally using a combination of an Arduino microcontroller equipped with DS18B20 thermocouple sensors and a HIKMICRO B20 thermal camera with the aim to find out how good stainless steel ice cubes for cooling food and beverages.  The time evolution of water temperature in glasses filled with stainless-steel cubes of various brands is compared with that of water ice cubes. The temperature field obtained from thermal images is used to further observe the overall temperature of water in the glass. Leeseph stainless-steel ice cubes are found to have thermal performance comparable to water ice cubes, while SSGP ice cubes can retain lower temperatures for a longer time compared with other ice cubes. The effect of the number of ice cubes (N), the volume of water (V), and the average diameter of the glass used (D) are also investigated. At 1 ≤ N ≤ 4, the larger number of ice cubes used are found to lower the minimum temperature, and to decrease the minimum time,  while at 150 ml ≤ V ≤ 300 ml, the larger amount of water used are observed to increase the minimum temperature and to increase the minimum time, . At 53 mm ≤ D ≤ 66 mm, larger glass diameter used are found to increase both the minimum temperature, and the minimum time
Co-Authors Amalia, Ismi Azhar Azhar Azwar Azwar Darmein Darmein Fauzi Fauzi Hamdani, Hamdani indra Mawardi Irwin Syahri Cebro Marzuki Marzuki Muhammad Muhammad Nurlaili Nurlaili Samsul Bahri Sumardi Sumardi Syamsuar Syamsuar Yuniati Yuniati Zuhaimi Zuhaimi Zuhaimi Zuhaimi