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The incidence of fishing boat accidents in Indonesia is very worrying, with 342 people dying during 2018–2020. Based on this, it is crucial to investigate the construction strength of fishing vessels against the possibility of a collision. In this study, the fishing boat due to the impact load was investigated in extreme weather conditions using Finite Element Method (FEM) analysis. Traditional fishing boat was constructed by measuring the thickness of the hull, deck, keel, frames, and longitudinal structure of the fishing boat. The collision model is carried out with an impactor in the form of a mooring pole during extreme weather with a wave height of 6 meters and wind speeds 30 knots. Variations in velocity and frame spacing as in actual conditions are modeled to obtain differences in deformation, absorption energy values, and plasticity of boat construction due to collisions. The collision speed of 30 and 20 knots are set on the extreme weather conditions, while the collision speed of 7 knots is set on operating speed. Frame spacing of 0.5 and 0.6 meters is built according to the boat's frame spacing in the field. Computer simulation is carried out using application software ANSYS Research License. The fishing boat material used is mahogany wood with tested by using impact test with a toughness value of 39.1 kJ/m2. Based on the simulations results, the impact velocity has an effect deformation wider crash area and hull stress value. The speed of the ship collision was 7 knots, the collision did not damage the hull, but the construction failed at speeds of 20 and 30 knots. The closer of frame spacing, the higher collision performance of structure to withstand impact are indicated by the higher energy absorption. At a ship collision speed of 30 knots, the absorption energy of the construction at 0.5-meter frame spacing is 49.8 kJ, greater than 0.6-meter frame spacing with a value of 29.6 kJ

Al-Zn-based AMC is a light metal, with low density, excellent mechanical and mechanical properties, suitable for use in automotive, electrical, general-purpose electronics, machinery and equipment. However, the development of this alloy is limited by its low hardness and low corrosion resistance, which limits its use in many applications. This corrosion process can cause fitting corrosion and can damage the passive oxide layer that protects the metal from corrosion. This study aimed to increase the corrosion resistance of AMC Al-Zn by adding hydroxyapatite ceramic reinforcement from snail shells in a corrosive medium of 3.5% NaCl solution. The HAp is used as an AMC amplifier. AMC uses Al-Zn alloys with a ratio of 90% to 10% by mass. The variation of HAp enhancer used was 10, 15, 20, 30 and 40% by weight. This AMC was produced by powder metallurgy using 250 KPa compression for 20 min with sintering at 550°C for 2 h followed by slow cooling. The characterization of Al-Zn-based AMCs was performed by electrodynamic polarization testing in 3.5% NaCl solution. From the experimental results, the addition of HAp snail waste at a concentration of 20% by weight with matrix composition Al90-Zn10 is an AMC preparation with optimal corrosion resistance. The corrosion rate of Al90-Zn10/20HAp is 0.01 mmpy, while the corrosion rate of Al90-Zn10/0HAp is 1.15 mmpy. The addition of HAp up to 20% by weight showed the highest micro-hardness (117.90 Hv) while the smallest micro-hardness occurred at AMC Al90-Zn10/0HAp (87.57 Hv). The HAp material could very well be used as an AMC-reinforced biomaterial for biomedical applications.

Aluminum is the most often used metal in modern industry and has a long history of use. This material has several advantages and downsides. Among the drawbacks are some aluminum alloys that cannot survive the corrosion rate produced by the environment. To address these problems, numerous procedures are used, one of which being anodizing. The goal of this procedure is to oxidize the metal surface, forming a coating of aluminum oxide that will protect it from the damaging impacts of the environment. As a result, the coating method is used. Stearic acid and lauric acid were employed in the coating procedure in this investigation. Stearic acid and lauric acid were employed in the coating procedure in this investigation. By performing the anodizing process first, then the coating process, the hydrophobicity properties of the many variations employed may be determined by examining the contact angle generated by the droplet outcomes. Untreated sample with a contact angle of 65° were found to have hydrophilic qualities, while the anodizing treatment had a contact angle close to 0°, and the anodizing process with stearic acid and lauric acid coating had contact angles of 117° and 130°, respectively. A sliding angle was also achieved for each treatment applied to the test sample, with the anodizing process obtaining a sliding angle of 59°, the anodizing process with stearic acid coating obtaining a sliding angle of 38°, and the coating with lauric acid obtaining a sliding angle of 28°. The coating utilizing stearic acid and lauric acid has strong hydrophobicity due to its superhydrophobic nature, which may resist the entry of water on the aluminum basis, according to the various treatments performed.

In the medical world, heat transfer studies can be used as tumor therapy. At a temperature of ≥40oC, a tissue will stop growing and die. One therapy that uses this concept of heat transfer is interstitial hyperthermia therapy. The high temperature given will certainly have an impact on the normal tissue around the tumor. Thus, the use of interstitial hyperthermia therapy requires the ability to adjust the right heat source, both based on space, time, and other supporting factors, such as metabolic heat, so that optimal success will be obtained. This study analyzes the influence of metabolic heat on the distribution of temperature in the human hands in interstitial hyperthermia therapy under unsteady conditions. The Pennes bioheat equation and the finite element numerical method are used to determine the value of the temperature distribution. This study was conducted for 600 seconds and variations in metabolic heat values were used in the form of 0 W/m3; 368.1 W/m3; 500 W/m3; 800 W/m3 and 1200 W/m3. In this study, metabolic heat influences temperature distribution that occurs in the interstitial treatment of hyperthermia therapy. This is because metabolic heat will provide heat from the inside so that the temperature in the tissue will increase.

Surface modification with plasma has been widely applied to polymeric materials. This treatment is intended to improve the surface properties of the polymer including its wettability and adhesiveness. The aim of this paper is to provide a review of the literature on the surface treatment of polymers with plasma, which focuses on the effects of adhesive and surface tribology properties. The related surface properties are also reviewed in order to strengthen the review of adhesive properties and tribology. Various types of plasma treatments that have been reviewed reported that plasma can be effectively used to improve surface properties, especially adhesive and tribological properties. On a small surface treatment has been developed plasma jet treatment which has been widely applied in biomedical applications.

Stainless steel 304 is one of the most widely used authentic stainless steel due to its high corrosion resistance. The use of cooking utensils can cause internal corrosion, where the inside of metal cookware and in direct contact with cooking ingredients will corrode and mix with food, so an organic coating is needed to increase its corrosion resistance. This study used chitosan as an organic coating with variations in chitosan concentration of 0.5; 0.4; 0.3; 0.2; and 0.1 wt%, the coating method used was electrodeposition, the voltage and coating time was kept constant at 10 volts and 10 minutes. After coating, the coated specimens will be tested for layer density, layer thickness, corrosion rate using a potentiodynamic polarization test. The results in this study obtained that the highest thickness and the lowest corrosion rate were on specimens with a variation of chitosan concentration of 0.5 wt% with a coating thickness and corrosion rate of 85.56 ± 4.67 m and a corrosion rate of 0.14403 mm/year, while the highest layer density was in specimens with a variation of chitosan concentration of 0.3 wt% with a layer density of 0.000360181gram/mm3. This is due to the viscosity of the electrolyte solution when coating, which affects the movement of electric current in the electrodeposition process.

Acrylonitrile Butane Styrene (ABS) is a type of polymer that can be metallized with metal through the electroless plating process so as to produce a strong and economical layer bond compared to metal. In this study, ABS plastic will be coated with nickel and the contact angle of ABS after the coating process will be examined. The first step is the etching process for 55 and 75 minutes using chromic acid to improve the adhesiveness and uniformity of the coating metal later. After the etching process is complete, then the surface roughness test is carried out using Mitutoyo SJ 201 Surface Roughness. Furthermore, the activation process with stannous chloride as a catalyst is carried out to accelerate the deposition of metal particles on the substrate surface so that during the electroless plating process the polymer turns into a conductor. Then the electroless plating process with time variations of 15, 25, 35, 45, 55 minutes using nickel sulfate, ammonium chloride, sodium hypophosphite, and sodium hydroxide to deposit nickel metal on the ABS surface. The results of the coating are then analyzed for surface topography using AFM and SEM, as well as investigating the contact angle of the droplets that are dropped on the coated ABS surface. It can be said that the etching variation of 55 minutes electroless nickel plating 75 minutes is the most hydrophobic because it has the largest contact angle and the smoothest surface topography compared to other variations.

Polylactidacid (PLA) is a type of bio-based and bio-degradable plastic. This substance is commonly used in the medical field since it is biocompatible and does not hurt bodily tissues. In this study, PLA plastic will be combined with chitosan (CS) via injection molding. The addition of CS to compensate for the absence of PLA with hydrophobic characteristics. CS has hydrophilic characteristics, which allow it to absorb water and bond with biological tissues. The contact angle test revealed that pure PLA is a hydrophobic material, but the PLA: CS alloy is a hydrophilic alloy.

The purpose of this study was to determine the effect of feed rate and depth of cut on the surface roughness of Al-Mg aluminum using a DIY CNC Milling Machine and Krisbow Universal Milling Machine as a comparison. The open-loop control system is a control system used in the design of DIY CNC Milling machines. A PC with Mach3 software is used as a PC Based Direct Digital Controller to control the system. In this study, the feed rate variation 24 mm/minute and 42 mm/minute and depth of cut 0.25 mm, 0.5 mm, and 0.75 mm were used. After the face milling process, the surface roughness test was carried out using the Mitoyo Surface Roughness Tester to determine the level of surface roughness of the machining results the DIY Milling Machine and Krisbow Universal Milling Machine as a comparison. The results showed that as the feed rate and depth of cut increased, the surface roughness values of both tools increased.

Environmentally friendly lubricants are lubricants that are easily dissolved in the environment and are not harmful to the ecosystem. It uses to reduce the heat in the contact area so that the machinability of the workpiece and the ability of the chisel will increase. To minimize the use of bio-cutting fluids, lubrication is carried out by minimum drop lubrication in the lathe process. The purpose of this research is to comply with the surface roughness of the workpiece and the shape of the chip. The material used is aluminum 6061, the natural oil used are rubber seed oil, virgin coconut oil, sunflower seed oil, and castor oil. The turning parameters were the depth of cut 0.5 mm, spindle speed of 330 rpm, feed rate 0.231 mm/rev, tool angle 90o, drop lubrication 192 ml/hour, infeed length 100 mm. The results of the research showed that virgin coconut oil has the lowest surface roughness. This is because the viscosity value of virgin coconut oil is very small so that the flow rate is able to work perfectly to lubricate the contact area. It has a thin chip configuration, the tool also wears but did not experience cracks.

This research aims to determine the effect of adding filler material in the form of waste material on Nitrile Butadiene Rubber (NBR) in making roller rubber to improve quality in terms of hardness and tensile strength. Each rubber roller compound is made from a mixture of NBR with rice husk, recycled rubber and wood charcoal. The process of making NBR and NBR with the addition of alloys is done with two roll open mixers at a certain temperature and time accompanied by the addition of certain additives. Furthermore, the compound is pressed using Hydrosan and then cut according to the standard test to be performed. The process ends by placing the material in an environment with a certain humidity level for 24 hours. Tests carried out include the test of hardness by using Shore A Durometer and Universal testing machines to test the strength of tensile strength. The test results show that the addition of recycled rubber can increase hardness by 30% when compared to NBR without the addition of filler. While the value of tensile strength for NBR and recycled rubber alloys is much higher.

Mechanical failure of zeolite-high density polyethylene (HDPE) material applied to skull bone implants is a material fracture that cannot be controlled. An important step to minimize failure due to fracture is to understand the fracture characteristics indicated by the propagation path pattern. This study aimed to investigate the fracture propagation pathways of zeolite-HDPE composites in quasi-static conditions. UV-irradiated Double-edge cracked zeolite-HDPE composite was tested in mode I (a stress perpendicular to the plane of the crack) in a universal testing machine (UTM) with a crosshead speed of 2 mm/min at a constant room temperature of approximately 25°C. The stress and elongation were registered by the UTM. During loading, the evolution of cracks in the ligament length region was recorded with the camera so that the crack propagation pathway until the total fracture occurs can be clearly observed. The results show that the crack propagation pathway patterns were not all straight and parallel to the ligament length. They are also found in a deviant state of the ligament length line by forming an angle α. created between the ligament length line and the fracture propagation deviation direction. This deviation occurs after the crack propagates straight away from the initial-cracks.

Corrosion is the deterioration of metal that can reduce its yield strength, ultimate strength, financial losses, waste of natural resources, and endanger security. Thus, the corrosion rate must be slowed , or if possible, stopped. This study aimed to investigate the mechanism of corrosion protection by using corrosion inhibitors of chitosan extracted from fish scales on ASTM A36 steel . ASTM A36 steel was used as the specimen with a thickness of 3 mm . F ish scales powder was used as chitosan source extracted by using three mechanisms, i.e., deproteination (7% NaOH immersion), demineralization (immersion of 1 M HCl in 100 ml) and deacetylation (immersion process with 70% NaOH concentration). Corrosion inhibitor was composed of 8 g of chitosan from fish scales , 50 ml of distilled water, and 1 ml of CH 3 COOH. Corrosion protection with the inhibition method was applied with variations in the inhibitor concentration (1000 ppm, 2000 ppm, 3000 ppm, 4000 ppm, 5000 ppm, and 6000 ppm ) . The corrosion rate was tested by the polarization method and Electrochemical Impedance Spectroscopy (EIS). The result demonstrated that the effectiveness of corrosion protection started to increase from the concentration of 1000 ppm, 2000 ppm, 3000 ppm to 4000 ppm , with an effective value of 46.444%, 56.386%, 59.691%, and 72.630%, respectively. However, the effectiveness level started to dec line from the concentrations of 5000 ppm to 6000 ppm, with 67.388% and 59.276%, respectively. This phenomenon occurs due to the inhibitor concentration has exceeded the maximum limit, so the interaction between inhibitor molecules was higher than the interaction between the inhibitor and the metal surface.

The aim of this study is to investigate the behavior of banana fiber (BF)-low-density polyethylene (LDPE) composite fracture toughness. The LDPE pellets are transformed into powder form which is then functioned as a matrix reinforced with banana fiber (BF). The composites were formed by injection molding techniques which are followed by atmospheric-pressure annealing at 90°C for 24 hours. The composite fracture toughness behavior was evaluated using the essential work of fracture (EWF) approach. The results show that fracture toughness which is characterized by essential fracture work (we) value increases by the presence of BF up to 5 wt.%. However, the we value starts to decrease in the composite with BF content of 6 wt.%. There is a mismatch about the phenomenon of non-essential fracture work. Stress-whitened zones can be seen and observed but non-essential fracture work based on curves is a negative value.

One type of aluminum that has a widely use is AA 6061 because it has a good mechanical properties and corrosion resistance when compared to the other types of aluminum. Those properties of this alloy can be improved even better by using the anodizing process. In this study, the results of anodizing AA 6061 will be investigated using molarity of sulfuric acid 1, 2 and 3 M, with an anodizing processing time of 60 minutes and temperature of electrolyte solution 10°C towards morphology and corrosion rate. The cathode used in this process is titanium alloy. After the anodizing process was completed, a Scanning Electron Microscopy (SEM) test was carried out to examine the surface morphology produced, testing Energy Dispersive X-Ray (EDX) is used to determine the chemical composition of the anodic layer formed after the anodizing process and the test of corrosion rate is done using 128N Autolab PGSTAT Potentiodynamic in 3.5% sodium chloride. From the test results, it appears that there is an increase in pore size and corrosion rate along with an increase in the molarity of the electrolyte solution. In addition, there is also an increase in sulfate levels and a decrease in titanium deposits in anodizing results with higher solution molarity.

The wet tissue company in this research has 46 volpack machines, 44 are used to produce wet sanitizer tissue and 2 other machines are used to produce wet cologne tissue. During this time, the company produces cologne type wet tissue where its production does not reach the production target. One of the causes of this problem was the high downtime influenced by the reliability of these components and machine; so causing the production capacity of wet cologne tissue to be reduced and company's production targets not achieved. Therefore, in order to achieve the company's production targets and to make the production process more efficient and effective, it is necessary good maintenance actions that pay attention to the reliability value of each critical component. This study analyzes the reliability of critical components so that companies can take action to increase their machine reliability.

One of the technologies that are developing rapidly is 3D printing. 3D printing machines can create objects easily, quickly and in detail. There are three main steps that a 3D printing machine goes through, namely design, printing and finishing. 3D printers using polylactic acid are widely used in various types of fields such as industrial machinery, spacecraft, consumer goods, electronic components, vehicles, medical industry, toy industry and others. In this research, we succeeded in making an educational game tool called Tetris with the 3D printing method using polylactic acid filaments. The process of consistently creating 3-dimensional objects from digital files by arranging many layers of thin metal in succession is called 3D printing. Using additive manufacturing technology, 3D digital designs are turned into virtual products by sequentially depositing metals. 3D printing provides reasonable feasibility to meet various parameters based on the engineering arena. By utilizing the advantages of PLA material, which has good tensile strength, good surface quality, is available in various colors and user-friendly, educational game tools are produced that have the advantage of being attractive, light, strong and easy to play. That way, making educational game tools using 3D printing made from PLA can solve the problems with previous educational game tools, which are not easy to play and less attractive to early childhood. Educational games that have been made in this study can be used as a platform for learning children at the kindergarten to elementary school levels. The way to play this educational game Tetris is by attaching shapes to the main part of Tetris and matching them with other shapes, just like playing a puzzle where each shape that is installed must match the other shapes

Organic chitosan synthesized from fish scales and food-grade chitosan were investigated, via the potentiodynamic polarization method, as potential corrosion inhibitors on ASTM A36 iron in 3.5% NaCl solution. The results of the study revealed that chitosan, both food-grade and that synthesized from fish scales, inhibited the corrosion of ASTM A36 iron in 3.5% NaCl solution. The source of the chitosan did not have any effects on the chitosan’s behavior or potential. The inhibitor efficiency value increased as the chitosan concentration increased. The optimum concentration of the two types of chitosan was 3000 ppm; the inhibitor efficiency value decreased when the inhibitor concentration was increased to4000 ppm. This inhibitor efficiency value change occurred because at 4000 ppm, the inhibitor concentration exceeded the best conditions to form a protective layer on the surface of ASTM A36 iron. Chitosan is cathodic, regardless of the source, and both types of chitosan were similar in terms of polarization type, adsorption, and isothermal adsorption. The isothermal adsorption interaction of chitosan (from either source) followed Temkin-type kinetics with the ASTM A36 iron and had chemisorption characteristics.

Of many compounds materials, metallic biomaterial is widely used in human medical devices. An implant material's corrosion resistance impacts its flexibility and longevity. This corrosion resistance is also an important consideration for biocompatibility. This biomaterial contains stainless steel whcih may corrode after being installed in the human body since the passivity of stainless steel disappears when it is exposed to acids in the human body for a long duration. In addition, lacks of oxygen inhibits the formation of a new Cr2O3 layer for corrosion protection. Based on this phenomenon, an advance treatment is required to improve the resistance corrosion of implant. This study investigates the effect of the concentration and duration of chitosan on the thickness and corrosion resistance of biomaterials. The concentration of chitosan used was 0.08%, 0.16%, and 0.24% while the voltage used was constant at 10 V. The test results demonstrated the lowest corrosion rate occrured for 0.24 % chitosan concentration with 30 minutes coating duration. The lowest corrosion rate achieved was 0.014 mmpy and the maximum thickness was 75.4 μm. This study could be then used as a new solution to increase the safety of existing implants using biodegradable and non-toxic compounds. The next experiment should be implantation in real human body.

The corrosion inhibition efficiency of Rhizophora acipulata(RA) extract was investigated for API 5L Steel corrosion in 3.5% NaCl using weight loss and polarization method. Fourier Transform Infra-Red (FTIR) was used toanalyze the characteristics of extract RA functional groups. The weight loss and polarization result indicated that extract RA inhibited API 5L steel corrosion rate. Based on the polarization result, the inhibition efficiency reached up 97.52% with addition 100ppm of RA extract.

Organic inhibitors have been considered as an effective way to control the corrosion of carbon steel weldment in an acidic environment. This work proposes a new green organic inhibitor made of extract of rambutan fruit (Nephelium lappaceum) peel and aims at analyzing its corrosion inhibitor properties and protection mechanism. Specimens of carbon steel weldment were tested for their corrosion by using electrochemical and immersion methods in 1 M HCl solution containing 0 to 6 g/L of Nephelium peel (NP) extract. Results showed that, in the same solution, the corrosion rate was measured to be higher on the weld metal zone than that of base metal zone, which could be related to the coarser grain of the weld metal zone and the stability of the formed oxide layer. The addition of NP extract was found to increase the stability of the oxide layer, thus increasing the corrosion resistance of the specimens. The maximum inhibition efficiency of the NP extract was reached at 97% for weld metal with 5 g/L of extract, at 80% for the heat affected zone with 5 g/L, and at 70% for base metal with 4 g/L. This work reveals the particularity of different weldment zones to the different needs of inhibitor concentration for obtaining the optimum corrosion protection.

Estimated damage levels from ballistic impact zones provide valuable information to make bulletproof materials more effective. This study aims to determine the impact of ballistics including deformation and energy absorption in fiber metal laminates (FMLs) that collide with 9 mm FMJ caliber bullets at speeds of 426 m/s. Finite element method modeling is done using ANSYS 18.1 workbench software. The simulation results show that FMLs can hold the bullet rate with deformation on the back of the target (DOPIII) of 8,55 mm and total energy absorption of 426,59 J at 0,000095 s. The combination of two materials, Al 5083 in the outer layer and kevlar/epoxy as the core, results in faster energy absorption and maximum stress concentrations only occur in the kevlar/epoxy so there is no damage to the first and subsequent layers.

This study was a preliminary study in applying chitosan as coating for tinplate. Tinplate is used as material for packaging because it is cheap, attractive, shiny, and easy to shape. Chitosan coating on tinplate with electrophoretic deposition (EPD) method and variation of EPD current was performed in this study. the variation of the current was 2, 4, 6,and 8 A. Coating thickness was measured using NOVOTEST TP-1M. The surface roughness was tested using Mitutoyo Surface Roughness Tester SJ-210. Corrosion test applied the polarization method of Potentiodynamic Autolab PGSTAT 128N with Control software NOVA 1.11. The corrosion test of the specimen was run in 3.5% NaCl solution. The specimens without treatment had higher corrosion rate compared to the specimen with EPD current of 8A which was 0.00061927 mpy. At the current variation of 8A, the coating thickness was 78.9 ± 1.58 %.The higher the current used in the EPD the lower the corrosion rate was. It was indicated by coating which protected tinplate and produced homogeneous coating. This was in line with the result of surface roughness which decreased with the increase of EPD current. The lowest surface roughness was at variation of 8A which was 0.152 µm.

Estimated damage levels from ballistics impact zone provide valuable information to make bulletproof materials more effective. Therefore, this study aims to determine the impact of ballistics including hole shape, hole depth, macro, and microstructure on fiber metal laminate. The characteristics of ballistics impact for each configuration target is obtained from experiment and comparison based on simulations with finite element method. Test experiments used short-barreled fire guns at a distance of 5 meters with a normal attack angle based on the National Institute of Justice standard. Simulation with Johnson-Cook plasticity models for aluminum plate and orthotropic material model for kevlar/epoxy. The experiment and simulation results showed that the projectile is able to perforate the first layer (aluminum plate) and the second layer (Kevlar/epoxy) while the last layer (backplate) is deformed to form a bulge. The aluminum plate is perforated by the failure of petaling formation on the backside and spread of dimple fracture around the area of the petal which indicates ductile fracture while kevlar/epoxy is perforated by projectile with failure of fiber fracture on primary yarn, fiber pull-out, fiber stretching and fiber rupture.

This study aims to investigate the effective coating time for ASTM A36 steel using chitosan in 1M HCl. In this study, ASTM A36 steel was used as a test specimen and the EPD technique was employed with coating time of 10, 20, 30, 40, and 50 minutes. The electrochemical technique was conducted using Autolab PGSTAT128N. In addition, this study also employed potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS). It was found that longer chitosan coating using EPD will produce better coating results.