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A well-known corrosion parameter is corrosion rate as measured by the electrochemical or the weight-loss methods. The weight loss methods can be measured continuously or intermittently depending on the actual conditions of sample placement and the experimental design. But what distinguishes the measurement method is whether they produce the same corrosion rate value or not. This study aims to study the corrosion rate with a continuous and discontinuous measurement method of weight loss using carbon steel specimens immersed in sodium chloride solution and further compare the two results. For this purpose, 25 sample coupons with the size of 80x23x3.6 mm have been prepared. The measurement of weight loss was carried out on specimens for 10, 20, 30, 40, and 50 days, by immersing the sample in 2 and 3%-wt NaCl, respectively, and one was treated in distilled water according to ASTM G31-72. From the three treatments studied, a percentage of the results was a value that lies between 2.67 and 5.46% with an average value of 4.17%. There is no significantly effect of the data collection method for the three types of the treatment samples immersed for 10 to 50 days in distilled water, 2 and 3%-wt sodium chloride solution.

The crankshaft is one of the main components of the combustion engine used for continuous rotation. Therefore, this research aims to analyze the crankshaft failure of a jeep with a four-cylinder diesel engine used to transport 4 tons of logs on rugged terrain and uneven roads for 12 months. This research was carried out using the Scanning Electron Microscope (SEM), microstructure, hardness, chemical composition, and stress analysis testing methods. The chemical composition and microstructure test results showed that the crankshaft was made of AISI 3150 material with a pearlite phase. From the results of the visual observation on the fracture surface, the characteristics of failure due to fatigue are indicated by a beach mark pattern on the fracture surface. SEM test shows a crack initiation at the edge of the balancer due to the dynamic loads experienced by the crankshaft, which causes propagation from the initial beach marks pattern to the final fracture.

The primary purpose of the structural study on the 4.2-meter-long Jaloe Kayoh boat is to analyze the FEA of E-glass and ramie fiber composites, as well as the polyester resin. The hand lay-up method was used in this study to manufacture specimens following the ASTM D638-02 standard, while the tensile test was performed under the ASTM D790-02 standard. Based on the simulation results, the data analysis method was used to visualize the relationship between the stress and strain strength parameters on the structure, as well as a reaction force and displacement, which were related to the centralized loading on the walls and hull of the Jaloe Kayoh boat with a minimum loading variation of 539.3 N and a maximum loading variation of 2157.4 N. The maximum loading of the stress strength on the hull wall of Jaloe Kayoh was obtained at a load of 220 kg or 2157.4 N. The stress values obtained were 4.212e+09 N/mm2 for E-glass fiber and 3.998e+09 N/mm2 for ramie fiber. The highest Reaction Force values obtained were 4.369e+03 N for E-glass and 4.952e+03 N for ramie fiber. The highest displacement value was obtained, which was 2.620e-02 m for E-glass fiber and 2.662e-02 m for ramie fiber. Based on the simulation results, E-glass and ramie fibers are still safe and feasible to use as a base or initial layer, or one of the supporting layers, for lamination on one of the materials for the Jaloe Kayoh boat's walls and hull.

The purpose of this work was to predict the fatigue life of the AISI 1513 carbon steel due to the strains measured at a vehicle's lower arm. The strain signals were acquired using a strain gauge installed at the lower arm, and then the car was driven at various road surfaces. On the smooth road surface, the car was driven at a speed of > 70 km/h and on the rough road surface, at a speed of < 20 km/h. The results show that when the vehicle was driven on the rough road, the lower arm received higher stress, which provided a shorter fatigue life. The contour of the road surfaces provided a vertical load, directly working the lower arm and reducing the load vertically. The fatigue life for the rough road surface was 13,050 cycles to failure. This value was 91,195% lower than the fatigue life on the smooth road surface.

This study examines the fatigue life of the SAE 5160 carbon steel as the material for an automotive coil spring subjected to road strain. The strain signals were acquired by attaching a strain gauge on the component, driving a car up- and down-hill roads. The results of the fatigue life assessment based on the strain-life approach show that the downhill road resulted in a lifespan of 15,000 cycles to failure, which was 53% lower than the uphill road. This value was a result of braking when the vehicle is moving downhill, causing stress to the component leading to shorter fatigue life.

This study aims to predict the fatigue life of the AISI 1513 carbon steel as the material for the vehicle lower arm subjected to road strains. Measurement of the strain signals was done by attaching a strain gauge at the left lower arm and driving the vehicle on clockwise and counter-clockwise roads at a speed of 30 km/h. According to the results based on the strain-life approach, the clockwise road gave the fatigue life of 2,600,000 cycles to failure, which was 1,862 % lower than the counter-clockwise road. It indicated that when the vehicle turned to the right, the lower arm on the left side subjected to a higher strain, resulting in a shorter fatigue life.

Micromachining technology is a challenge in industrial production to meet the demand for components for machinery. In this research, a study of the best parameters was required to produce the best hole accuracy and the lowest burr formation in the inlet and exit holes using micro-drilling. The work-piece material and cutting tool used respectively was a brass plate with a thickness of 0.5 mm and a micro drill with a diameter of 0.2 mm commonly used for electronic PCBs. The quality of holes was measured and observed by using a stereomicroscope (optical equipment). This microscope can zoom up to 50x objects to facilitate measurement. The microscope was attached by using a digital camera type YW-200 so that the object of observation could be measured using a computer. The result shows that the largest deviation of hole diameter (0.217 mm) occurred at a spindle speed of 14,000 rpm with the lowest feed rate (5 mm/min). Meanwhile, the smallest deviation of hole diameter (0.202 mm) occurred at a spindle speed of 20,000 rpm with a maximum feed rate of 10 mm/min. The maximum burr height (0.050 mm) occurred at a spindle speed of 17,000 rpm and a feed rate of 10 mm/min. In addition, the minimum burr height (0.038 mm) occurred at a spindle speed of 14,000 rpm and a feed rate of 5 mm/min. Therefore, it can be concluded that the deviation of hole diameter was inversely proportional to the spindle speed, and the height of the burr formation was directly proportional to the feed rate.

The stress distribution and deformation formed by various loading conditions are a crucial thing to be considered during design. Stress and deformation maximum area should be a primary concern, and this study will discuss the stress analysis and displacement of the bike frame (T-I profiles) through the Finite Element Analysis (FEA). Five scenarios loading conditions have been applied which is expected to represent various situations that happen in the actual performance of the bicycle frame. Loading conditions are the static start-up, steady-state pedaling, vertical-horizontal loading, and rear wheel breaking. Cross-section of bike frame comprises into two forms. There are “T” profile on the mainframe and “I” profile on stay. The simulation results in this paper show that von-mises stress ranging from 7.18 - 36.83 MPa which are spreading over several areas of this bike frame such as seat beam, chain stay-seat stay, top beam, and drop out, depending on the position of the loading applied. Subsequently, the maximum deflection that the bike frame from this design is obtained is 0.018 - 0.23 mm (simulation results). Optimization of this bicycle frame is needed for future development.

Soldier’s activities resulted in too much workload received by the body, especially in the back and waist. These conditions produce a high risk of musculoskeletal disorders especially if conducted continuously. The soldiers must carry a backpack containing supplies during training weighing up to 40 kg on average. All activities are conducted manually until the training is finish. Thus, the purposes of this study are to reduce spinal injury by identifying factors resulting from lifting loads that exceed the limits of the body, calculate the maximum load limit that can be carried by a soldier, and produce artificial exoskeleton as a tool for the Indonesian Armed Forces. The study used anthropometry, biomechanics, and physiological approach in solving the problem. The results show that the safe load can be carried by the soldiers is 30.46 kg. The body parts that feel the complaint are the upper neck, back, shoulder, buttocks. In addition, this study can produce a design of an artificial exoskeleton with the following dimensions: chest thickness 23 cm, chest width 32 cm, back length 52 cm. The soldiers can increase the force load by 9% of the initial weight of the load using this design.

A composite material is a combination of two or more different materials between resin and fiber. The characteristic of this material is that it has a high level of corrosion resistance. This study aims to analyze the strength and durability of Jaloe Kayoh made of jute fiber polyester composite materials. Static analysis on Jaloe Kayoh is carried out through simulation or modeling using CAE-based software with the Finite Element Method (FEM), in static-general conditions. The parameters studied include the stress and strain values for centralized loading on the body of the boat with a minimum load of 650 N and a maximum load of 1950 N. The variations of the materials applied to Jaloe Kayoh include jute, jute-glass, jute-glass-jute, and fiberglass. From the simulation results on the 1950 N loading, the maximum stress is obtained by the jute-glass material with a value of 3.356 × 109 Pa. The greatest maximum strain by jute-glass material is with a value of 1.442 × 10−1. The results of this study show that the four composite materials are categorized as good to be applied as the main material of the Jaloe Kayoh.

Numerical analysis for the traditional Aceh fishing boat was studied with three loading scenarios, such as 2100, 3500, and 4200 N and four thickness variations are 3, 4, 5, and 6 mm. The analysis carried out involved stress, strain, and displacement on the low carbon steel St-37 alloy. This simulation aims to analyze the maximum stress, strain, and displacement of a traditional Aceh fishing boat with several variations in loading conditions and hull thickness. Then it is produced using CNC plate cutting techniques and assembled with welding techniques. The load is applied evenly to the lower half of the surface on a traditional Aceh fishing boat with the assumption boat receiving a pressure load from the water when it is placed above the water level. The results show are that the maximum load and strain are 340 MPa and 1.1 × 10−3 with third scenario loading conditions, the load is 4200 N which was applied to the simulation with a plate thickness of 6 mm. The maximum displacement was 4.76 mm in the third scenario loading conditions (the load applied is 4200 N), with a plate thickness of 2 mm.

In this paper, an experimental study was carried out to evaluate the number of layer effect of abaca fiber composite as natural reinforced polymer (NFRP) material for shear-strengthened reinforced concrete (RC) beams. Two externally bonded shear-strengthened beams with a different number of NFRP layers and a sound beam as a control beam were prepared. The test was conducted by applying two axial loads on the beam. The results showed that the use of one-layer and two-layer of abaca fiber composite as NFRP material for the shear-strengthened beam increased 9.78% and 9.92% of maximum load compared to sound beam respectively. Abaca fiber composite NFRP material contributed 11% and 18.57% of the total maximum shear load for one-layer and two-layer laminates respectively. In addition, externally bonded shear-strengthened beams affected the crack pattern and deflection value. However, debonding failure of NFRP laminates occurred in two-layer of the NFRP shear strengthened beam. It caused the beam did not work optimally.

Electric vehicles are a necessity now, especially in the future. The efficiency of electric vehicles continues to be improved, especially in the drive system or electric motor. One type of electric motor used in an electric vehicle that has high efficiency and power density is permanent magnet axial flux motor. This paper explains the comparison of power density on two designs of axial flux motor. A single and multi-air gap axial flux motors had been compared. The finite element method (FEM) simulation is used to determine the power and volume of those motors. The results presented that the two air gaps power density axial flux motors were 195,3 W/kg while those multi air-gap motor with four air gaps had 283.6 W/kg. The results shoes that four air-gap has a bigger power density than two air-gaps.

The WEC (Wave Energy Converter) that uses a permanent magnet linear generator continues to develop. The most important thing to know in designing WEC with a linear electric generator is the thrust required by the linear generator itself. Therefore, this paper discusses and analyses the thrust that occurs in linear electric generators used in WEC systems. Linear electric generators are simulated using FEMM (Finite Element Magnetic Method) software. FEMM simulation is used to analyse the magnitude of the induced magnetic field received by the conductor at a certain position of the stator. The conductor is given a constant current so that it produces thrust force between the stator and translator; the magnitude of thrust force depends on the magnitude of the magnetic field at the position. In the design and analysis, conductors ware given 3A. The maximum thrust force in the linear electric generator design is 79N, and the average force is 75N, force ripple is 1,2%. The design of the permanent magnet linear generator was done, and the WEC system should produce thrust force at least equal to the force that the generator requires.

A rowing athlete requires effective and systematic physical training. Thus, an ergometer is very influential on the endurance of an athlete’s body and becomes a vehicle of simulating groundwater rowing. However, the ergometer tool currently used has no specifications and dimensions that are in accordance with the anthropometry of male rowing athletes in Aceh. Based on these conditions, the rowing ergometer tool will be designed based on the anthropometry of rowing athletes in Aceh. Data retrieval was done by taking samples from six male rowing athletes. The data were then tested for the level of trust, accuracy, uniformity, and adequacy. From the results of data analysis, the design of the ergometer tool was in accordance with the anthropometry of male rowing athletes in Aceh. This situation can build comfort for male athletes and increase the endurance of their muscles. This includes maintaining the tempo of rowing and being able to move oars with long distances in a short time.

Salted fish is dried fish that is preserved by adding salt as the preservative medium. The process of production starts with cleaning, salting, boiling, drying, sorting, and packing. The length and complexity of the process lead to an increase in the risk of MSDs and posture complaints among the workers. This study aimed to find out the factors that caused the complaints with the biomechanical posture method. Six subjects were measured for the tension at erector spinae and the moment at (lumbar 5 sacrum 1) L5-S1 vertebral joint created by body segments and load, the calculation of the workers’ body segment weight, the distance of the body’s center point to the lumbar 5 sacrum 1 (L5-S1), and biomechanics at L5-S1. The largest body segment weight was found at the cleaning station, which dealt with the process of manually lifting the fish, with a bodyweight value of 70 kg, Wtrunk: 350 N, Whead: 58.8 N, Warm: 35.7 N and Wload: 300 N. The farthest distance from the body’s center point to L5-S1 was found at the drying station, which deals with the process of drying the fish, with values of the distance of head (dhead): 54.78 cm, distance of trunk (dtrunk): 59.26 cm, distance of arm (darm): 67.39 cm and distance of box (dbox): 86.11 cm. The largest moment in force on L5-S1 was found at the packing station, which deals with the fish transferring and packaging process, with the value of the moment of force at 5351.86 N and 4215.28 N. Therefore, it is suggested that the salt fish industry finds solutions, re-designing the work station, decreasing the lifting load, and producing proper equipment to assist workers during labor to improve their safety and health.

Burnout is a psychology syndrome which experienced by any professions throughout their careers. This study analyses burnout syndrome encountered by hospitals’ nurses based on the Maslach Burnout Inventory-Human Service Survey (MBI-HSS) and provides findings by looking at the dimension of burnout and demographic factors which consist of sex, age, marital status, level of education, years of career, and duty station. This study reveals that; the overall value of burnout experienced by hospitals’ nurses is categorized into level 1 with the highest value presented by dimension 1 (physical exhaustion), and burnout generally experienced by man, nurses younger than 30 years old, married nurses, lower degree nurses, nurses whose less than 20 years in career, and nurses whose responsible in terminal care and emergency unit. In addition, data obtained from the survey is utilized to determine burnout causative factors using fishbone and pareto diagram.

The paper discusses the size of six body segments of the Indonesian Male Army, i. e. stature, leg length, chest depth, chest width, spine length and shoulder high. The particular body segments were believed as the most important body part that related to the strength and load handling capability of humans as reported by researchers. Two hundred and sixty-eight (268) male soldiers have participated as the subjects of this research. The size of the body segments and the body weight were measured by using measuring tape, Martin type anthropometer and digital body weighing scale. The result was analysed to observe the significance of the data as well as to determine the mean, standard deviation, 5th percentile and 95th percentile of the data. The comparison of the mean stature with Indonesian male students and male army of other countries was discussed in the paper. In future research, the result of this study will be used to predict the load handling capability of the Indonesian male army using the biomechanics method.

The welding process can affect the mechanical properties of the metal. This study was aimed at examining the effects of welding on the strain rate of AISI 1005 carbon steel. Shield metal arc welding, utilizing an E6013 electrode with a diameter of 2.5 mm, a double V-notch with an angle of 120°, and a welding position of 1G, was used to weld low carbon steel. A tensile test was performed to determine the mechanical properties of the steel at various strain rates to represent the loads that it would be subjected to. The test was performed at strain rates of 3 mm/min, 9 mm/min, 15 mm/min and 20 mm/min. The results showed that as the strain rate of steel increased to 20 mm/min, the maximum tensile strength of 447.67 MPa and highest yield strength of 362.94 MPa were obtained, while the lowest values were obtained at a strain rate of 3 mm/min. An examination of the fractured surfaces using SEM showed that at the strain rates of 3 mm/min, 15 mm/min and 20 mm/min smaller voids were formed.

This research focusses on the effect of vegetable oils, i.e. crude palm oil (CPO) and coconut oil (CO), used as the cutting fluid on the wear of carbide cutting tool insert in a face milling process. The performances of the tool, in term of wear and the surface roughness of the workpiece, were investigated and compared to those resulting from a similar milling process but using conventional cutting fluid, which is a commercial soluble oil emulsion (SOE). The results show that at the spindle speed of 360 rpm and the feed rate of 80 mm/min, the tool wear was smaller in the case of CO than that in the case of CPO cutting fluid, which is 0.16 mm2 compared to 0.40 mm2, respectively. The tool worn area in these cases are still larger than that in the case of SOE, which is 0.09 mm2. However, at higher spindle speed of 490 rpm and feed rate of 80 mm/min, the smallest tool worn area occurred for the case of CO cutting fluid, which is 0.04 mm2, compared to 0.1 mm2 and 0.11 mm2 for the case of CPO and SOE cutting fluids, respectively. As for the workpiece, the achieved surface roughness, Ra, were relatively similar for all the evaluated cases.

This chapter discusses the development of a simplified human head finite element model. It comprises of four components: the skull, facial bones, cerebrospinal fluid (CSF) and the brain. The material properties of each component are adopted from various literature.

Mechanical hands that resemble a human’s hands are used to replaces tasks and improve safety. The three stages of the mechanical hands manufacture include designing using a computer application (CAD), then analysis of stress distribution using finite element application, and finally, processing the prototype production using conventional machines. The mechanical hands are designed using a kinematics model approach, and then it is simulated using 1000 N of load to obtain the stress and strain in each section. The simulated test results showed that the mechanical hands can move with 11 Degree of Freedom (DoF), and able to receive a 1000 N load. Thus, it can be concluded that this mechanical hand prototype can be used to hold, grasp and squeeze a few basic shapes, such as spheres, beams, and pipes with a diameter of at least 0.03 m and a maximum of 0.07 m.Mechanical hands that resemble a human’s hands are used to replaces tasks and improve safety. The three stages of the mechanical hands manufacture include designing using a computer application (CAD), then analysis of stress distribution using finite element application, and finally, processing the prototype production using conventional machines. The mechanical hands are designed using a kinematics model approach, and then it is simulated using 1000 N of load to obtain the stress and strain in each section. The simulated test results showed that the mechanical hands can move with 11 Degree of Freedom (DoF), and able to receive a 1000 N load. Thus, it can be concluded that this mechanical hand prototype can be used to hold, grasp and squeeze a few basic shapes, such as spheres, beams, and pipes with a diameter of at least 0.03 m and a maximum of 0.07 m.

In the previous chapter, soccer heading simulations were performed and validated against the literature. It is evident that the FEA predictions of the linear and angular head accelerations were in a good agreement with the published experimental data of soccer heading. In this chapter, similar simulations were conducted, but with the inclusion of a headgear modelled on the forehead of the head model. The subsequent sections describe the methods and discuss the results obtained from the aforementioned FE simulations.

This chapter covers the review of literature that motivates this work. This includes a brief overview of sports-related head injuries, particularly in soccer, and the efficacy of protective headgears in mitigating the impact due to soccer heading.

In the previous chapters, the FE models of soccer ball and human head were developed and validated against published experimental data. This chapter covers the simulation of a soccer heading manoeuvre, whereby the aforementioned models were assembled and positioned accordingly to replicate an actual soccer heading manoeuvre. The subsequent sections detail the simulation methods, as well as discuss the results obtained.

This chapter describes the development of the soccer ball FE model and its validation. The geometry of the ball and the material properties of each layer of the ball model are presented. In addition, the pressurization of the ball is also described. The model was validated against a more advanced soccer ball model.

Heading occur frequently in soccer games and studies have shown that repetitive heading of the soccer ball could result in degeneration of brain cells and lead to mild traumatic brain injury. This study proposes a two degree-of-freedom linear mathematical model to study the impact of the soccer ball on the brain. The model consists of a mass–spring–damper system, in which the skull, the brain and the soccer ball are modelled as a mass and the neck modelled as a spring–damper system. The proposed model was compared with previous dynamic model for soccer ball-to-head impact. Moreover, it was also validated against drop ball experiment on an instrumented dummy skull and also compared with head acceleration data from previous studies. Comparison shows that our proposed model is capable of describing both the skull and brain accelerations qualitatively and quantitatively. This study shows that a simple linear mathematical model can be useful in giving a preliminary insight on the kinematics of human skull and brain during a ball-to-head impact. The model can be used to investigate the important parameters during soccer heading that affect the brain displacement and acceleration, thus providing better understanding of the mechanics behind it.

There has been a long debate among researchers on whether soccer heading is capable of causing brain trauma. A recent study suggests that headings exceeding a threshold level of 855 to 1,550 per year, results in microstructural abnormalities in the brain's white matter. This shows that brain trauma is caused by cumulative effect of repetitive headings. The use of protective headgear is one of the suggested preventive measures to protect the brain especially for younger players. Researchers have tested several commercial headgears and found that they are only effective in head-to-head impact, but ineffective in attenuating impact caused by heading. This is due to the fact that soccer ball is compliant in nature relative to the head. The aim of this study is to investigate materials that can be utilised to minimise the acceleration of the brain caused by soccer heading. A vertical drop ball test was conducted on an instrumented dummy skull. The inner cavity of the skull is filled with ultrasound gel that represents the brain. Six impact-absorbing materials were tested to determine the most effective material that reduces the acceleration of the brain substitute. The speed of the ball before and after impact as well as impact duration were measured using high-speed camera. Coefficient of restitution was calculated to ensure the material is not only capable of reducing the brain acceleration, but also maintains heading performance. It was found that polymer kneepad foam is the most effective material that minimises the acceleration of brain substitute whilst maintaining the speed of the ball after impact.