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One of the most important components of a Hybrid Rocket Engine (HRE) is the nozzle which functions to control the rate of flow, pressure, and speed of stream distribution in the convergent-divergent nozzle. Recently, HRE has potential as a future propulsion system. In this paper, to obtain the ideal HRE expansion outlet, the geometry of the divergent angle of the nozzles had simulated. The analytical results are used to compare the Mach number, pressure and temperature measurements with aimed to found the geometry with the most ideal expansion nozzle. Computational Fluid Dynamics Analysis (CFD) analyzed various performance parameters in detail for the HRE nozzles from inlet to outlet using software Ansys Fluent. Convergent angle, throat diameter, and length of the nozzles had the same geometrical dimensions, the divergent section used 6°,9°,12°,15°,18°,21°,24°,27°,30°,33° variations of angles. After the simulation, the results showed that the highest Mach number was Mach 1.59914 at the 6° divergent angle and the lowest was Mach 0.213108 at the 33° divergent angle. The highest pressure was 437259 Pa at the 18° divergent angle and the lowest was 298470 Pa at the 6° divergent angle. The temperature fluctuated as the divergent angle increased with the highest at 2801.91 K at the 9° divergent angle and the lowest was 2326.72 K at the 15° divergent angle. Furthermore, the results revealed oblique shock shifts closer to the throat caused the Mach number decreased at the outlet as the divergent angle increased, and a change in cross-sectional diameter due to an increase of nozzle divergent angle also caused head loss minor (expansion) occur. The 6° divergent angle allows having the most ideal geometry in terms of the highest Mach number output with the lowest pressure closest to the ideal expansion. [ABSTRACT FROM AUTHOR]

The strength of 3D printed part is an important factor that must be considered before carrying out a product design. The purpose of this research is to observe the surface quality and tensile strength of 3D printed part that is reinforced by epoxy resin. The specimen models were designed according to ASTM D3039 standards and printed using a 3D printer device. During the printing process, the layer height of deposit layer was varied into three different types while the main material used as a base material PLA. Furthermore, the specimens were divided into two categories, specimens with coating of resin polymer and without any coating. The coating process was conducted to the test specimens using a vacuum bagging technique by utilizing a vacuum pump as an air suction device. The specimen without any coating process were directly surface roughness test and perform tensile test directly. Based on the test results, lowest of surface roughness was occurred on specimen with resin coating. However, the highest tensile strength was showed by specimens without any surface coating. Although the addition of resin polymer shows a significant effect, but the layer height is not too significant. [ABSTRACT FROM AUTHOR]

Depending on the requirements of the material applied in the medical field (orthopedics and dental), titanium and its alloys play an important role as a conforming material and have been widely used. However, despite the properties that have met the requirements, the surface of titanium and its alloys still requires modification to achieve antibacterial properties. One of the antibacterial agents is silver material. This article focuses on reviewing the modification technique of silver attachment on titanium surface which is specifically used as a biomaterial that has been developed in the recent years. Furthermore, adjustments withinside the floor shape of diverse silver attachment strategies are comprehensively mentioned accompanied through antibacterial properties. In addition, the potential of the silver embedding method was also reviewed which leads to novelty in this field. Thus, future research can focus on effective methods for improving the structure and composition of silver plating on the surface of titanium and its alloys. [ABSTRACT FROM AUTHOR]

Shear Thickening Fluid (STF) is a type of Non-Newtonian Fluid whose viscosity increases as the strain rate increases. STF has been applied in various fields, one of which is on soft body armor. STF consists of dispersion medium and dispersed phase particles. Recently, STF does not only consist of 2 phases but is multiphase. Multiphase STF includes the second phase in suspension and in this case the additives particles. Various additives particles (types and properties) have changed the thickening behavior of the STF which increases the ballistic resistance by increasing the density of the suspension and the dynamic strength of the material in the fluid. This review explains the effect of additive particles on the rheological properties of STF and ballistics on soft body armor. Furthermore, the review is also focused on understanding the potential of particle additives in STF and the development of particle additives along with a review towards novelty in the STF field. Furthermore, the focus of this review is the particle additive applied to STF with the literature reviewed relatively recently (last 5 years). [ABSTRACT FROM AUTHOR]

Stress intensity factor (SIF) is one of the parameters in determining the stress at the crack tip caused by crack nucleation. Prediction of stress at the crack tip using LEFM (Linear Elastic Fracture Mechanics) and EPFM (Elastic Plastic Fracture Mechanics) approaches through SIF and J-integral becomes very important in estimating crack propagation, life and energy release rate. This study aims to analyze the SIF simulation (mode I and mode III), fatigue crack growth rate and J-Integral on leaf spring failure using ANSYS. The initial simulation carried out is preprocessing including crack design 5 mm, crack tip meshing with sphere radius = 10 mm and element size = 0.5 mm, while the boundary condition for the applied force is 3500 N. Failure will be dominated in the opening mode because mode I has the highest SIF value of KI = 469.67 MPa √mm compared and KIII = 386.27 MPa √mm. This is in accordance with the calculation of the analysis of the number of cycles and the fatigue crack growth rate where mode I has a lower number of cycles, namely 187500 cycles compared to mode III of 29000 cycles, while the fastest fatigue crack growth rate is produced by mode I. The decrease in strength is also analyzed based on the J-Integral analysis where, mode I produces a value of 3.809 mJ/mm2 and mode II 3.790 mJ/mm2 [ABSTRACT FROM AUTHOR]

The performance of the hybrid rocket engine (HRE) cannot be separated from the role of the rocket injector. Many things can affect the performance of the injector performance on a hybrid rocket engine. The type of fluid used and the shape of the injector geometry play an important role in affecting the performance of the resulting injector. Simulations were carried out using ANSYS software using the k-epsilon turbulence model. The purpose of this study is to determine the difference in terms of value of the output pressure and fluid velocity which is affected by differences in geometry and the type of fluid used. The geometry variables used in this study are 2 inlet geometric shapes and injector angle variations. The injector angle variations used are 65°, 45°, and 90°. The types of fluid used in the simulation process are gaseous oxygen (GOX) and liquid oxygen fluid (LOX). Based on the simulation results, the largest outlet pressure and velocity are found in the injector design with a first inlet geometry and an angle of 90° using GOX fluid of 2605.33 Pa and 98.7503 m/s. The smallest outlet pressure is found in the injector design with a second inlet geometry and an angle of 65° using LOX fluid of -964,792 Pa and the lowest outlet velocity is found in the injector design with a second inlet geometry and an angle of 90° using LOX fluid, which is 0.0289349 m/s. The outlet pressure value, if analyzed analytically should have a positive value, but the simulation results found some negative results. This happens because of turbulence in the fluid flow simulation which causes the simulation results to be irrelevant when compared to the analytical approach using dynamic fluid equations. [ABSTRACT FROM AUTHOR]

In engineering systems, vibration is one of the many problems that appear. Vibration causes losses such as reduced performance, loss of energy, damage, and reduced comfort. Many methods have been developed to reduce vibration in engineering systems, one of which is the use of dynamic vibration absorbers (DVA). In this study, the vibration characteristics of the 2 DOF system added with DVA were analyzed experimentally and numerically. Experimental analysis was carried out by making several modeling of the vibration system which was then compared with numerical calculations. The mass of the DVA added to the system with 100 gram mass. Mass located at top of spring and then bottom of spring. As a result, the amount of mass in DVA affects the vibration characteristics (speed, frequency, amplitude, mass normalization, and frequency normalization). For this study, amplitude and frequency will be the main output from experimental and numerical approach. The difference between experimental and numerical results for all models is not more than 15%. So that the vibration model with the addition of the tested DVA can reach an agreement between the numerical and theoretical results. The 100 gram mass of DVA added at the top spring gives more 50% absorbtion and when mass added at the bottom of spring gives less than 25%. From this study, experimental and numerical approach give an agreement because the deviation is not more than 15% and the located mass at the of the spring gives better absorbtion. [ABSTRACT FROM AUTHOR]

Titanium has been broadly used for numerous packages within the pitch of medical, aerospace, modern equipment, etc. Behind the advantages of titanium, namely high strength, titanium has problems in machinability. The method that can be used to overcome this problem is to apply cooling and lubrication methods during the titanium machining process. In this article, the recent progress and applications of lubrication and cooling methods such as dry, Minimum Quantity Lubrication, Nanofluid MQL (MQL), and cryogenics on titanium are discussed. The machining processes in the machining reviewed include milling, turning, drilling, and grinding. The results show that the cooling and lubrication methods in the machining process influence surface integrity and characteristed of the resulting machining. The review in this article also discusses the development of cooling and lubrication methods and the potential of coolants for machining. Furthermore, that future research can produce titanium machining with high surface integrity quality with a biodegradable and environmentally friendly coolant. [ABSTRACT FROM AUTHOR]

Crack analysis on coil spring is intended to simulate stress, fatigue life, SIF mode I, II, J-Integral, and fatigue crack growth rate. Simulations were carried out using the Ansys Static Structural approach. The material used was tested for its composition and obtained SAE 9260 steel material is. The simulation results in conditions without crack show that the stress concentration point occurs in the 2nd coil according to the location of the coil spring fracture with an equivalent value of von misses 1236.1 MPa below the ultimate tensile strength value of SAE 9260 material. The results of the stress intensity factor value show that mode II shows the highest value was KII=171.11 MPa mm , compared to the value of KI=97.175 MPa mm . This is following the analysis of the number of cycles and the fatigue crack growth rate in mode II which has a lower number of cycles of 97500 cycles compared to mode I which is 677700 cycles, while in mode II it has a critical crack size value of 10.28 mm followed by a drastic decrease in strength. The maximum value of J-Integral for the given crack is 0.33962 mJ/mm2 which is located at the end of the crack. [ABSTRACT FROM AUTHOR]

Increasing the volume of combustible motor vehicles, needs to be anticipated as early as possible if there is a failure on the combustion engine components. Failure that may occur on the component is the connecting rod. This study aims to determine the cause of the failure of a connecting rod car. The method used in this study consisted of several tests namely, macro photographs, microstructure test, SEM/EDX and hardness test. The results show that the specimen is AISI 4315 with a hardness of 30.98 RC. The specimen has a hard surface but is resilient on the inside. This can be seen from the shape of the fault that has a lot of dimple, beachmark, and fracture folds. [ABSTRACT FROM AUTHOR]

Crash box is one of the passive safety systems located between the bumper and main frame of the vehicle. The main function of the Crash box is to absorb energy due to collisions or collisions experienced by vehicles. Crash box has various forms of diverse cross sections. Although it has a cross-section of diverse, however opportunities to improve the energy absorption in a crash box is still quite high. One of them is given a crash initiator. Crash initiator Air the potential to increase the value of energy absorption. The purpose of this study is to analyze the effect of crash initiator on the absorption of crash box energy due to impact loads. This study targets the development of the value of energy absorption effectively by providing crash initiator equalization. The achievement of initial research is to provide equalization of the crash initiator using the finite element method through ANSYS software with the Geometry of the crash box used circle, hexagonal, and origami trapezoid. Each type of crash box is given equal distribution of crash initiator to increase the absorption of energy obtained after getting an impact load. Furthermore, an experimental study to compare the values obtained between simulation and experiment. [ABSTRACT FROM AUTHOR]

This study aims to increase the energy absorption value of previous researchers by comparing the crashbox given by Full Crash Initiator with a crashbox without crash initiator. Crashbox that is used has circle, hexagonal, and origami trapezoid. This analysis was carried out through the finite element method with the help of ANSYS software with a collision speed of 7.67 m / s. The results of this study indicate that giving a full crash initiator to a crashbox can increase the value of energy absorption compared to without a crash initiator. [ABSTRACT FROM AUTHOR]

UAV (Unmanned Aerial Vehicle) is an unmanned aircraft or also called a military drone with long range coverage because it can air on a matter of days. One development that continues to stand out is the BWB type UAV where, the angle of wing bending varies. This research is for simulation of wing angle bend between 45, 60 and 90 degrees. The method used in the simulation uses the Finite Element Method with the help of ANSYS 17.0. Haisl's research shows that at an angle of 45 degrees the airflow within the wing is fairly normal and evenly distributed. The pressure on the BMB also increases with the addition of the speed and angle of bend. On the results of the study also showed that the value of the lift is inversely proportional to the value of drag. [ABSTRACT FROM AUTHOR]

CNC Milling 5 axis both using mathematical theory and with the prototype performance test. Theoretical mathematics used is the Finite Element Method (FEM) with the help of ANSYS 18.1 software while for the design of the 5 Axis CNC Milling using Auto CAD software. Undeniable design of the shape and performance of CNC Milling. The simulation results show a maximum displacement value of 9.8703 microns. The biggest displacement is at the front end of the top of the chassis. The results of the simulation of Voltage Intensity on the CNC 5 Axis Milling machine chassis show the maximum value of the voltage intensity of 0.288 MPa. The greatest stress intensity at the lower end of the hole on the spindle is shown in red. Next, try the prototype, which starts with the chassis casting process which is divided into three, the first part chassis, the second part supporting pole, and the last one is the top chassis. [ABSTRACT FROM AUTHOR]

Increasing the volume of combustible motor vehicles, needs to be anticipated as early as possible if there is a failure on the combustion engine components. Failure that may occur on the component is the connecting rod. This study aims to determine the cause of the failure of a connecting rod in the car. The method used in this study is a finite element method (FEM) simulation. The simulation results show that, cracks that are near the big end have greater stress and strain values than the area far from. [ABSTRACT FROM AUTHOR]

The needs of the manufacturing industry are increasingly increasing, one of them is by increasing the number of CNC production. However, damage to CNC often occurs due to CNC performance that exceeds the limit. One of the damages is on the CNC supporting bolts where continuous loading occurs. The purpose of this study is to simulate a 5 Axis CNC Milling especially on the bolt section. The simulation is intended to find the shear stress, total deformation and stress equivalent. The simulation uses the finite element method with the help of ANSYS 18.1 software. The results showed that the maximum shear stress was 192.69 MPa and the maximum total deformation was 0.022105 mm. [ABSTRACT FROM AUTHOR]

In this study, the open-cell aluminium (Al) foam was fabricated through the melting route, utilizing vacuum casting. The different contents of fly ash particles were homogeneously added into the melt for the alloy reinforcement. The < 5 mm silica gel (SiO2) particles were filled into the mold cavity for the space holder during the foam casting. Afterward, the compressive test was performed on the foam samples by utilizing a universal testing machine under a constant strain rate of 1 mm/min. The addition of a higher amount of fly ash particles shifted the yield strength into a greater value. In parallel, the elastic modulus was also higher when more fly ash content is used in Al foam reinforcement. On the other hand, the maximum strength at 60 % strain decreased after 2.5 % fly ash addition and subsequently rose by further content of reinforcement. These phenomena are strongly related to the porosity and microstructural state of the fabricated foam formed after SiO2 removal. The results indicate that adding a certain amount of fly ash can modify the compressive properties of Al foam by acting as dispersive strengthening particles and withstand the cellular structure from early deformation during loading. [ABSTRACT FROM AUTHOR]

As a unique structure, aluminum (Al) foam is extensively used in heat transfer, low weight-high stiffness structure, and energy absorption applications to answer the new technological needs in energy saving. This study analyzed the compressive strength of open-cell Al foam fabricated using spherical silica gel (SiO2) particles as a space holder with the variation of particle grain size. The Al scraps were initially melted inside the furnace at 800 °C and subsequently poured into a heated cylindrical steel mold filled with SiO2 having various particle sizes. The vacuum pressure was spontaneously applied just after the melt completely fill the pouring basin. After the remained SiO2 had been removed from the foam specimens, the porosity was measured. The compressive test was conducted on the cylindrical foam specimens using the universal testing machine (UTM) and the macroscopic appearance of outer cellular fracture was captured during the test. The results showed that the larger SiO2 size generates the higher porosity level of 63% at 5 mm particle size. This higher porosity corresponds to the forming of the larger size of pores in the center of specimens. Consequently, at higher porosity, the compressive strength value obtained was lower with only 4.10 MPa, compared to those with the particle size of 3 mm (10.41 MPa) and 4 mm (6.25 MPa), as confirmed by the compression test. The data obtained from the experiment could provide an overview for those who want to develop Al foam with a certain level of strength. [ABSTRACT FROM AUTHOR]

leaf spring is a vital component in a motor vehicle - particularly in car either with light tonnage or with heavy tonnage. It is needed to function both as the load buffer and as a shock absorber. This simulation was aimed to observe the strength of leaf spring due to the loading by varying the tilt angles or curvature on two different materials: composite material of 65Si7 and composite material of C17000. The declivity of leaf spring here consists of 0, 5, 10, 15 and 20°C.The result of the analysis showed that the characteristic of leaf spring using the material of composite of 65Si7 has resulted in the maximum stress compared to the leaf spring using the material of composite C17000. The characteristic of leaf spring using the material of composite C17000 has resulted in the total deformation and the strain larger than that of the leaf spring using the composite material of 65Si7. For the use of leaf spring on vehicle, it is better to use the composite material 65Si7 rather than the composite material of C17000. [ABSTRACT FROM AUTHOR]

Piston is an important component of the motor vehicle that can pump or result in a pressure thus enabling to generate the components to reciprocate the engine. Commonly, it is made of mixed aluminum in which in the work process of engine, it receives the high level of pressure and heat that later emerges the pressure on the surface. To observe the distribution of the surface pressure on the piston due to the high pressure and temperature, it cannot be manually done but by means of the approach of the finite element method through the Ansys sofware. The variation of the simulated surface pressures consisted of 5, 10, 15 and 20 MPa with various pedestals given. Based upon the simulation result, it was found that the variety of the pressures received by the piston surface has caused the level of pressure experienced by piston also changed. It was similar with the result of the use of different positions of pedestals in which it could lead to a change in the pressure concentration of piston. [ABSTRACT FROM AUTHOR]

There are several researchers have examined laminated bamboo beams. The outcomes revealed that laminated bamboo beams had high flexural strength but low elastic modulus. The low modulus of elasticity causes the beam to have low stiffness so that the high flexural strength cannot be utilized optimally. This study seeks to analyze the increasing amount of beam stiffness by adding CFRP along the tensile and or compressive sections of the beam. To get the result, a numerical simulation was carried out on laminated bamboo beams with a cross-sectional of 50 mm in width, 50 mm in height, and a span length of 1,400 mm. There are three groups of beam treatment, the name given for CFRP in both tension and compression zones, in the compression zone, and in the tension zone. The length of CFRP for the three treatments is the same as the span of the beam. The results of the numerical analysis showed that the beam with the addition of CFRP experienced a significant increase in stiffness. Compared to the stiffness of the beam without CFRP, the beam with the addition of CFRP in both the tension and compression zones, in the compression zone, and the tension zone, experienced an increase in stiffness of 66.21%, 51.19%, and 15.89%, respectively. The model of damage to the beam is divided into flexural damage and shear damage. The simulation results indicate that the beam with the accumulation of CFRP in both tension and compression zones encountered flexural damage and shear damage; the beam with the addition of CFRP in the compression zone underwent flexural damage, and the beam with the addition of CFRP in the tensile zone experienced flexural damage and shear damage. [ABSTRACT FROM AUTHOR]

For making an aluminium (Al) foam through the melting route, a pressurized process such as vacuum casting is considered a potential technique due to its feasibility to flow the melt through a narrow area in a short time. In this work, cylindrical Al foam was cast using spherical silica gel (SiO2) particles as the space holder. After the SiO2 particles were loaded inside the cavity, the mold was then pre-heated under different temperatures (80, 100, and 120 °C). Afterward, Al melt was poured onto the basin and subsequently filled the cavity under the vacuum pressure of -20 inHg and the foam was released after it was solidified. Before moving into the compressive test, the SiO2 particles were dissolved into the solvent and weighed to measure the porosity. Although showing the higher porosity, the compressive test revealed that the lower mold temperature resulted in higher maximum compressive strength and elastic modulus of 18.38 MPa and 1.55 GPa at the strain limit of 60%. It implied that the microstructure played an important role to characterize the compressive properties of the open-cell Al foam. [ABSTRACT FROM AUTHOR]

Unmanned Aerial Vehicles (UAVs) are unmanned aircraft that can fly from long distances using remote control or flying with an autonomous system. Blended Wing Body (BWB) is one of the UAVs being developed. In this research, the angle of the winglet and air velocity is varied to performance of the BWB-UAV lift force (Lift), drag force (drag) and moment. The Computational Fluid Dynamic (ANSYS 17.0 Fluent) approach is used to simulate the BWB-UAV model that was made. Furthermore, the results of the lift, drag and moment are recorded and analyzed. According to the results, it show that the bend angle of 0° (without wings) gives a fairly large amount of turbulent air to the wing tips, while at an angle of 45° the air flow on the wings of the aircraft is lean distributed. In addition, the pressure on the BWB-UAV increases proportionally in speeds of air and bend angle of winglet. In this study, it is distinct that the lift is inversely proportional to the drag value where the increasing lift can also increasing the drag value. [ABSTRACT FROM AUTHOR]

The pelvic bone fractured surgery commonly includes a plate implant as a part of assembling the fragmented bone fractured. One of the important process of pelvic bone surgery is a plate implant design that is often performed by bending process for getting a shape plate appropriate to the contour of the pelvic bone. This study was purposed to observe the characteristic a Ti plate alloy implant of the bending process by using Finite Element Analysis approach. The stress distribution and deformation of the plate were evaluated to variety distance of dying from the middle axis before and after maximum loading. The punching depth was set as the main load of punch. Hence, the angle of the plate under bending load and spring-back load were recorded and calculated for getting the resultant degree of slope. The existing resultant angle of plate model was caused by stress distribution on the plate. As reported on this study, the reducing distance of die from the middle axis could increase the maximum stress and reduced the spring-back effect so that the plate shape error could be minimized for assembling pelvic bone fractured. The increasing resultant angle of the plate was influenced by punching depth as well as recorded in this study. [ABSTRACT FROM AUTHOR]

Indonesia is an abundant egg producing country. When the eggshell is not managed properly, the eggshell will become a medium for microbial growth and cause environmental pollution. Eggshell contain very high calcium carbonate which can be used as a precursor for hydroxyapatite formation. The biocompatibility and bioactivity of hard tissue in the natural tissues of bones and teeth, hydroxyapatite can be applied to the medical world as an ingredient to cure damaged bones and teeth. In the process of eating food, mastication occurs in the oral cavity where the strength of mastication depends on several factors. This study aims to find out as optimal as the factors that influence the process of mastication. The crystallite size obtained from phase identification by X-Ray Diffraction and the morphology of eggshell powder obtained from a Scanning Electron Microscope. The experimental design process used Taguchi method and statistical tool used analysis of variance (ANOVA). The parameters for experimental design are crystallite size of the eggshell powder and mastication amount. The result shows that the optimal condition that can increase the strength of mastication is the crystallite size of 107 nm with the amount of mastication 40 times. The parameter that most contributes to the increase in masticatory strength is the size of the crystal with a percentage of 97.11%. [ABSTRACT FROM AUTHOR]

Samarium as rare-earth materials has excellent magnetic properties when synthesized and combined with cobalt. This paper aims to synthesized SmCo5 through the sol-gel method with a variation of sintering temperatures at 400, 500, and 600°C to explore some of the properties and possibilities that can be created from these materials. Then, Xray Diffraction raised the presence single-phased by occurred the crystallites on all samples in all temperature variations with crystallite sizes that calculated by the Scherrer’s equation. The results are as follows 17.730; 15.197; and 13.296 nm in 400, 500, and 600°C samples respectively. The morphology showed in SEM results that the particle shapes and sizes were relatively large and agglomerated. The average size of particles of the three sample in 400, 500, and 600 °C sintering temperature are 153.86; 154,81; 193.56 nm. Some bonds on the samples detected on FTIR result. Those are alkyl halides, alkanes, and esters with aromatic functional groups on the fingerprint area; and alkynes, alkyl halides, and alcohol functional groups in above 1500/cm wavelength. The magnetic properties test result using VSM indicated that the material is classified as soft magnet material with high coercivity and retentivity in samples sintered at 500 °C. However, the highest saturation occurred in samples sintered at 400 °C. [ABSTRACT FROM AUTHOR]

Laminated bamboo is engineered as a substitute for timber for building structures. Just as in steel structures, structural elements such as beams and columns require connecting elements. Glued-in rod (girod) is one of the connecting techniques that are being developed. The addition of a channel bracket at the glued-in rod connection is done to simplify the work method when applied to multistory building. This study aims to determine the bending behavior of the glued-in rod-channel connection. The connection flexural behavior in terms of strength, stiffness, ductility, and the type of failure. The numerical method used in this research is the finite element method. The variations used in this study are connection configurations (4 girods and 6 girods), and steel diameters (6mm; 8mm; and 10mm). From the results of the finite element analysis, the connection strength will be validated with the relevant theory. The results showed that the strength and stiffness of the 6-girod configuration was higher than that of the 4-girod configuration. The maximum strength for the 6-girod configuration with diameters of 6mm, 8mm, and 10mm are 4.22kNm, 6.45kNm, 11.85kNm, respectively. While the stiffness values for the 6-girod configuration with diameters of 6mm, 8mm, and 10mm are 154.0kNm/rad, 167.1kNm/rad, 178.7kNm/rad, respectively. Connections with a diameter of 6mm and 8mm have met the ductility requirements of SNI 1729:2020 with a ductility index of 2.38 for 6mm diameter and 4 girods, 2.06 for 6mm diameter and 6 girods, 1.63 for 8mm diameter and 4 girods, and 1.25 for 8mm diameter and 6 girods. All types of connections are classified as simple connections and non-seismic connections. The type of failure in the connection using 6mm and 8mm diameter is a steel rod fracture, while service ability failure occurs for the 10mm diameter. [ABSTRACT FROM AUTHOR]

Duralium is kind of non-ferro alloy that used widely in industrial. That caused its properties such as mild, high ductility, and resistance from corrosion. This study aimed to know mechanical properties of duralium on single step and three step articial aging process. Mechanical properties that discussed in this study focused on toughness value, tensile strength, and microstructure of duralium. Toughness value of single step artificial aging was 0.082 joule/mm2, and toughness value of three step artificial aging was 0,0721 joule/mm2. Duralium tensile strength of single step artificial aging was 32.36 kgf/mm^2, and duralium tensile strength of three step artificial aging was 32,70 kgf/mm^2. Based on microstructure photo of duralium of single step artificial aging showed that precipitate (θ) was not spreading evenly indicated by black spot which increasing the toughness of material. While microstructure photo of duralium that treated by three step artificial aging showed that it had more precipitate (θ) spread evenly compared with duralium that treated by single step artificial aging. [ABSTRACT FROM AUTHOR]

The object of this study was to optimizing design new technology in the form of a Goose-Leg water wheel from locally available materials and that was suitable for use in local condition with the view (i.e. free water flow) to increase national electricity supply to more remote areas. In order to further the objective, the water wheel vanes are to be designed employing simulation through Computational Fluid Dynamics to obtain an optimum vane width, to do this the following widths were analysed: (1) 600 mm, (2) 700 mm, (3) 800 mm and (4) 900 mm. The simulation process was enacted in 3 stages: preprocessing, solving and postprocessing. The optimization design produced the following results: (1) that moment pressure values rose in the 600 mm, 700 mm and 800 mm width vanes, (2) that moment pressure dropped with the 900 mm width vane, (3) optimum moment pressure was reached with the 800 mm width vane. [ABSTRACT FROM AUTHOR]

Duralium has mild character, high ductility, and resistance from corrosion. Doing heat treatment against this alloy by cooling variation can increase strength and ductility of this alloy. Cooling media variations which is used for this research are 10% dromus oil + water, 20% dromus oil + water, and 30% dromus oil + water. The purpose of this research is knowing the tensile strength of duralium in artificial aging process against cooling media variation 10% dromus oil + water, 20% dromus oil + water, and 30% dromus oil + water, type of fracture, and phase changing of duralium. This research include in experimental research category which uses the one-shot case study research model. Tensile testing uses Hung Ta Instrument machine and type of fracture is observed from micro and macro photo of duralium. The aging result shows that tensile strength of duralium increase from 8.3304 Kg/mm2 to 8.6229 Kg/mm2. This is due from aging result which is formed precipitates evenly due to the difference of cooling media on hardening process. Brittle fracture on duralium specimen can be found in artificial aging process by 10% dromus oil + water cooling media. Mix fracture on duralium specimen can be found in artificial aging process by 20% domus oil + water as cooling media. Ductile fracture on duralium specimen can be found in artificial aging by 30% dromus oil + water as cooling media. The important discovery of this research is phase changing in artificial aging process can be influenced by difference of cooling media on hardening process. [ABSTRACT FROM AUTHOR]