In the context of the 4th Industrial Revolution, the rise of electric vehicles and personal mobility is evident. However, regulatory authorities seem to overlook vast opportunities, placing two-wheelers in a deregulated category and focusing mainly on regulations. This paper addresses a notable trend in e-mobility, emphasizing aspects often overlooked in traditional motorcycle regulatory research. Using the industrial life cycle theory as a basis, we identify challenges that have affected traditional combustion-engine two-wheelers and offer insights to navigate similar obstacles in the future. Consequently, the domestic two-wheeler market experienced a brief surge but lacked sustainable growth prospects. However, considering Japan's success in establishing global standards and design dominance in the two-wheeler industry despite its late entry, there appears to be potential for a rebound in the domestic market.
With the advancement of optical design and manufacturing technology, optical components have found diverse applications, spanning from semiconductors to the aerospace industry. A reflective mirror is a basic component in optics and plays a crucial role as the medium to reflect light. In this paper, a large mirror with a 700mm diameter was designed as a primary mirror using fused silica. The rear side of the mirror was subdivided into several equal angles, and neighboring vertices on the circumference were connected to establish a polygon. Accordingly, the geometric shapes of triangle, square, pentagon, and hexagon were formed. Furthermore, the mirror structure was strengthened by employing straight lines passing the vertices and the center of the circle. Based on the finite element analysis, deformations of the mirrors caused by the gravitational force were evaluated. Weight and deformation of the mirror structures were compared and analyzed to find a proper structure to reduce weight and deformation. This paper, therefore, presents a structural solution aimed at reducing the weight and deformation of a large aperture mirror induced by gravitational forces, thereby suggesting a geometric shape based structure to reduce surface deformation of a mirror.
Cars using diesel have always had problems with reducing exhaust fumes, and have been studied steadily in this regard. There were studies on the remanufacturing effect of DOC catalyst deactivated by diesel vehicle smoke reduction device, analysis of vehicle fire accident cases caused by damage to diesel vehicle smoke reduction device, and related studies on the remanufacturing effect of diesel vehicle smoke reduction device DPF. This study is also to develop an exhaust flow control unit suitable for an exhaust engine to completely burn smoke generated by an engine using a diesel engine in a low temperature exhaust gas. The main systems to be developed are high-performance heaters, burner structures that can maintain ignition in exhaust flows, and exhaust flow control units that reduce exhaust gas backflow effects caused by diesel engines.
The objective of this study is to analyze the difference between the theoretically calculated torque values of lead screws used in vehicle seat rails and the required torque values due to various disturbances that occur in actual systems. Lead screws were classified into square and trapezoidal threads and modeled by two lead type. Dynamic analysis models were constructed by applying contact conditions and rotational joints between the lead screw and nut. The validity of the dynamic model was verified by comparing the torque values obtained from rigid body dynamic analysis with the theoretically calculated torque values. Then, the lead screw was modeled as a flexible body to investigate the torque variation required for the lead screw when dynamic loads are considered. This study will help predict the actual torque values of lead screws for seat rails.
This paper is a study on the malfunction that occurred during the power supply logic of the Gunner Display Device during Mortar Functional Firing under low temperature conditions. As a result of the phenomenon reproduction test and its analysis, the cause of the malfunction of the Gunner Display Device was Glitch, which occurred in the process of converting the image signal, and the improved software was applied to the Gunner's Display System by ignoring some of the image signal conversion process that causes Glitch. The improved Gunner Display Device passed the validity test and applied the improvement to the mortars. As a result of this study, several suggestions for power supply and control logic were proposed. It is expected that this study will be used as a reference in the future design of similar weapons systems.
Raman distributed temperature sensor can be used as temperature instruments as well as monitoring abnormalities in next-generation nuclear systems. Since noise reduction and Measuring Frequency enhancement are required, integration time adjustment has been mainly used so far. In this study, a new data processing method using Moving Average Filter was analyzed to see if noise reduction and Measuring Frequency could be reduced, and improvement measures were suggested.
Recently a biosafety level-3(BL-3) mobile laboratory has been set up for the virus scanning and vaccine development because of the COVID-19 pandemic. The study on air flow inlet and outlet location and its flow direction with ventilation in the mobile laboratory needs to prevent spread of COVID-19 virus because the COVID-19 virus is primarily transmitted to people through respiratory droplets and aerosol coming out as their coughing. This study is conducted on the air flow pattern optimization in BL-3 mobile laboratory with various design specifications of position of air supply & exhaust port and particle source. Air flow patterns of ceiling supply-exhaust and ceiling supply-bottom side exhaust with particle source were determined to compare the impact of the infection prevention. CFD simulation was used to analyze for two air flow patterns and particle source position. Numerical results showed that air flow pattern of air conditioning system with ceiling supply-exhaust in a row is more effective than that of ceiling supply-bottom side exhaust air flow pattern in terms of infection prevention in biosafety mobile laboratory.
Tendon-driven mechanisms have gained prominence in a range of applications, including soft robots, exoskeletons, and prosthetic devices. These mechanism use flexible tendons or cables to transmit force and control joint movement. As the popularity of these mechanisms grows, there is an increasing demand for solutions to enhance stability and safety. The use of brakes is a well-known solution, but existing models are difficult to customize for small soft robots. In this paper, we present a one-way shape memory alloy-based compact brake for tendon-driven mechanisms. The proposed soft brake featured a thin design and was tailored for seamless integration within a tendon-driven mechanism. In addition, the use of the one-way shape memory alloys enabled the design of the brakes that are both compact and powerful. This brake is expected to be widely used in miniaturized tendon-driven robots.
The domestic shipbuilding industry is building high-value-added ships such as LNG and LPG, and the demand for natural gas, a clean energy source, is continuously increasing. Climate change, such as global warming, is occurring due to rising oil prices and excessive use of fossil fuels. To protect their homes from the changing environment, 121 countries announced intensive climate target policies to reduce carbon emissions to 0% by 2050. In this study, modeling and design were performed using SUS410 and SUS304L about the operating part of the Pilot valve based on the physical properties of the aluminum alloy used in the Pilot valve, a component of the gas pressure Regulating valve for LNG ships. Numerical We want to develop the optimal Pilot valve by comparing and analyzing the results using ANSYS, an analysis simulation program.
This study explores strategies to address the variability of heat energy using renewable energy and heat grids to achieve carbon neutrality. Renewable energy source introduce fluctuations that can impact the stability of power systems, while heat grids provide a systematic infrastructure for efficient supply of heat energy and power generation. Jeju Island is chosen as a case study, focusing on balance control based on groundwater-based geothermal energy to optimize the distribution of heat energy. The results demonstrate that the 3rd control method is the most effective in maintaining the target temperature in greenhouses, and specific temperature settings and objectives are proposed for each control method based on crop requirements. These research findings contribute to achieving carbon neutrality and reducing power consumption.
Prepreg is an abbreviation of Preimpregnated Materials. It is a sheet-type product in which a matrix is impregnated with reinforced fiber. The prepreg has very different properties depending on the orientation of the fibers and the weaving method, and the orientation of the fibers plays an important role in determining the mechanical strength of CFRP. Short and randomly oriented reinforcing fibers show isotropy, while long, unidirectional reinforcing fibers exhibit anisotropic behavior and are strongest when the applied load is parallel to the reinforcing fibers. Classification by the direction of the fiber is divided into unidirectional, orthogonal, multiaxial, and the like. Uni-directional refers to a state in which almost all fibers in the fabric are aligned in one direction. When the fibers used as reinforcing materials are aligned in one direction, the fibers are used in a straight line without twisting during the fabric production process, and there is an advantage in that the amount of fibers used as a whole can be minimized. A uni-directional prepreg exhibits different cutting forces depending on the stacking orientation angle. In this experiment, the optimal cutting conditions for a uni-directional prepreg 45 degree orientation angle specimen are presented.
This study examines the persistent decline of the motorcycle industry despite governmental interventions, using the perspective of path dependency. Drawing from W. B. Arthur's concept of 'Lock-in by insignificant historical events', the research delves into the lock-in phenomena within the industry's life cycle. We identified path dependency lock-in categories: contingency, historicity, and technological lock-in. The industry's licensing production method during its embryonic phase led to limited technological capabilities, establishing a technological path dependency. During the currency crisis and in alignment with China's open-door policy, the industry chose to import cheaper components, opting for economies of scale over technological innovation, intensifying the lock-in. Furthermore, the classification of motorcycle as a free industry before the currency crisis resulted in a lack of governmental support. This neglect has continued, with even modern electric motorcycle facing regulation. In conclusion, to overcome this entrenched path dependency and lock-in, significant governmental policy restructuring is essential.
The sampling test module of the existing AMC Monitoring System is constructed using tubes and fittings, so there has been a problem with molecular contaminants remaining in the system. This study demonstrated how a new manifold-type sampling test module without connecting tubes and fittings, and with super-hydrophobic coating improves residual molecular contaminants in the AMC Monitoring System through CDA purge when molecular contamination occurs in a clean room with a Semiconductor Fabrication.
Combat-armored vehicles were equipped with an automatic-fire-extinguishing system to ensure the safety of the crew and vehicle from fires on the vehicle. When a fire was occurred, the automatic-fire-extinguishing system automatically detects the fire through sensors and detection lines, sprays a fire extinguisher, and notifies the crew visually and audibly. Recently, there had been cases of automatic-fire-extinguishing systems malfunction on combat-armored vehicles. In this study, in order to resolve the automatic-fire-extinguisher's malfunction phenomenon, ground noise and inter-circuit noise generated from the fire detection line were identified, and the resistance connected on the circuit was revised to remove noise. As a result of resistance revision, the noises was eliminated and the electromotive force difference between input circuits was made constant, thereby improving the malfunction of the automatic-fire-extinguishing system. By applying the result, it was confirmed that the control device sensed a temperature similar to the actual temperature on actual vehicles, and it was confirmed that the automatic-fire-extinguishing system's malfunction phenomenon was not founded in the field vehicles after then.
The EV electric vehicle market is growing rapidly worldwide. Magnet fixing technology is important for mass production of driving motors, a key part of electric vehicles. The magnet fixing method was carried out by the PAM (Polyamide molding) method. This study conducted the injection of rotor core magnet PA of EV traction motor and is a study on the amount of rotor core deformation. In this study, the change in the outer diameter of the product after injection and the non-molding phenomenon were tested. An injection mold was made and the results and phenomena of product deformation types are discussed.
Recently, in the case of the root industry, although it is a basic industry that forms the basis of manufacturing competitiveness, there continues to be a shortage of manpower due to reasons such as dangerous working environments, industrial economic difficulties, and low wage systems. In addition, the demand for automation of production lines using robots is increasing due to a shrinking labor market due to a decrease in the working population due to aging, higher wages, shorter working hours, and limitations of foreign workers. In this study, a system was developed to automate the injection molding process for producing ball valves for automobiles by applying robot system. The applied process flow consists of alignment and insertion of insert parts, and removal, transfer, and loading of the product after injection molding, which is currently performed manually. Through the application of the developed robot automation system, the cycle time was improved by more than 30% and the defect rate was reduced by more than 70%.
This study investigated how to repair high-pressure pipes by applying the expansion method instead of the welding method used to repair pipes in the steel, petrochemical, and shipbuilding industries that use high-pressure pipes, and developed a pipe-specific expansion device and auxiliary equipment to use the expansion pipe. We developed an expansion device with a range of 65A to 125A, evaluated the characteristics of the equipment, and manufactured high-pressure pipes made with this device, and obtained the following conclusions. The pressure resistance performance test of the non-welded expansion device was carried out at 32A to 125A, and the pipe pressure resistance test showed good results, and the durability test confirmed the durability of 0.0061 to 0.0063mm. The vibration test of the developed expansion device was measured at 0.3~0.5mm/s, and the noise measurement result was 65.1~65.5 at 32A, 65.2~65.5 at 65A, and 65.4~66.6dB at 125A.
As the importance of the indoor environment increases. In response to that, performance test study was conducted for the development of high performance range hood. And the chamber casing mock-up was subjected to a performance test by applying a static pressure of 100[Pa] in accordance with KS C 9304: 2020, When the discharge port diameter was 100 mm, the standard flow rate() was 186.9 at 60.8W, the discharge port diameter was 125 mm, and the standard flow rate() at 52.0W was 184.6, which satisfies “B-type 160 to 200 (static pressure 100Pa)”. This is a result that meets the KS C 9304 : 2020.
Injection molding is a process of shaping resin materials by heating them to a temperature above their melting point and then using a mold. The resin material is injected into and cooled within the mold cavity, solidifying into the desired shape. The core and cavity components that make up the mold cavity are crucial elements for the precision molding in injection molding. In the case of precision mold production, the application of 5-axis machining technology is required to ensure high machining quality for complex shapes, and among these factors, the tool angle is a critical machining condition that determines the surface roughness of the workpiece. In this study, we aim to measure the surface roughness of the machined surface of KP4A specimens during machining processes with variations in the tool angle and analyze the correlation between the tool angle and surface roughness.
In electric vehicles, the core is a secondary cell battery. Raw material is pulverized by the grinding disc in the Classifier Separator Mill (CSM) and rises through the Classifier Wheel. Both require characteristics to withstand high-speed rotation, including abrasion, corrosion, and shock. Our study analyzes the impact of RPM and heat source on temperature, convergence, and durability. In conclusion, high heat increases flow, while high RPM reduces the maximum temperature but may harm durability. Proper RPM settings enhance durability.