Carbon capture and storage is a vital strategy for mitigating rising atmospheric carbon dioxide, and metal–organic frameworks (MOFs) have gained attention as promising sorbents. Numerous simulations have examined factors governing CO₂ capture in MOFs—such as diffusion in MOF-74 under varying temperatures and process modeling of MOF-5—but most were limited to specific structures or conditions, hindering a systematic understanding of diffusion across diverse MOFs. Conventional computational methods also face constraints: density functional theory mainly provides static energy evaluations, while molecular dynamics relies on fixed force fields with poor transferability and an inability to describe reactive events. To overcome these limitations, this study employs molecular dynamics simulations driven by neural network potentials to evaluate CO₂ diffusivity in 17 types of MOFs. Results reveal significant variation in transport behavior, with zeolitic-imidazolate framework-3 showing the highest diffusivity and MOF-74 the lowest—an approximately 19-fold difference. These findings highlight the capability of neural-network-based molecular dynamics to deliver consistent and quantitative assessments of CO₂ transport in MOFs, providing a reliable framework for the rational design of next-generation capture materials.

Facility Layout Problem (FLP) aims to optimize arrangement of facilities to enhance productivity and minimize costs. Traditional methods face challenges in dealing with the complexity and non-linearity of modern manufacturing environments. This study introduced an approach combining Reinforcement Learning (RL) and simulation to optimize manufacturing line layouts. Deep Q-Network (DQN) learns to reduce unused space, improve path efficiency, and maximize space utilization by optimizing facility placement and material flow. Simulations were used to validate layouts and evaluate performance based on production output, path length, and bending frequency. This RL-based method offers a more adaptable and efficient solution for FLP than traditional techniques, addressing both physical and operational optimization.

This paper presents a line-of-sight (LOS) stabilization control method for portable optical systems by analyzing fast steering mirror, image sensor, and gyro sensor system. To compensate for LOS errors caused by hand tremors in portable optical systems, we present the configuration of an image sensor-based LOS stabilization control system and a control strategy considering the phase delay effect caused by low sampling frequency of the image sensor. The phase delay effect of the image sensor caused restricted bandwidth, which limited the stabilization performance. To overcome such limitations, we present disturbance feedforward control using the gyro sensor and controller design method considering characteristics of the gyro sensor. Through overall system modeling, we constructed a control simulation model. The LOS stabilization performance against hand tremor disturbances was analyzed based on the proposed controller design. Simulation results demonstrated that integrating a gyro sensor-based disturbance feedforward control with the image sensor-based LOS stabilization control significantly enhanced the stabilization performance.

The purpose of this paper was to develop a simulation model for a 40 kW electric tractor using a powertrain based on dual motors and a planetary gear. To select motor capacity and reduction gear ratio based on the power flow for agricultural work, load data for various gear conditions were acquired and analyzed using a 42 kW engine tractor of similar capacity. Modeling was conducted using MATLAB/Simulink/Simscape. Load data acquired through actual field tests were applied as load conditions for the simulation. Simulation results confirmed that the power was transmitted through the planetary gear as the clutch and brake operated according to the work mode. The developed simulation model is expected to be used for electric tractor development.

As system performance continues to improve at higher resolutions, it becomes increasingly important to establish standards for imaging degradation caused by optical windows. In this study, random surface shapes were simulated on large area optical windows with peak-to-valley (P-v) values of 0.25, 0.5, and 1.0 λ. Modulation Transfer Function (MTF) values were derived for 1,000 cases per P-v value using Monte-Carlo simulations. The specifications achieved a surface accuracy of 0.5 λ and a parallelism of 0.01 mm. MTF measurements showed that the system MTF was 13.5% prior to the installation of the optical window, and 13.1% after installation. This indicates a degradation rate of approximately 3%.

The use of reflective optical systems is essential to acquiring high-resolution image quality in aerospace applications that observe distant objects. The geometric shapes of large-aperture reflective optical systems can be deformed depending on various operating and space environments, which deformation consequently affects optical performance. In this study, we predict the image quality of a reflective aerospace optical system according to various environmental changes. In particular, the shape deformation due to vibration and heat generated from the launch vehicle was mainly observed, and the effect on gravity was also considered. The variations of image quality, such as Modulation Transfer Function (MTF) and wave-front error (WFE), were also observed by importing the deformed shapes into the optical simulation tool. This study is intended to provide approaches to reduce the cost and lead time to develop aerospace optical systems.

The utilization of aerospace technology is growing to meet various requirements of climate change sensing, communications, and the military. Large aperture and precise reflective optical systems such as mirrors are needed to acquire high-quality data, and the requirements of lightness, low cost, and low deformation should also be met to operate in the space environment. In this review, we highlight the recent progress of reflective optical systems for aerospace applications. In particular, optical systems for artificial satellites and homing optics are mainly introduced, and optical and mechanical simulations are discussed according to operating environments. We also discuss various reflective optic designs, materials, and operating principles for aerospace applications, such as a homing head and optical payload. We hope that this review provides approaches for developing surveillance systems, exploring space, and addressing the climate crisis.

Factors such as weight reduction and improved fuel efficiency of vehicles interfere with the efficiency of roller bearings in automobiles under harsh conditions. In particular, studies are ongoing to increase the load capacity and rigidity under highspeed conditions. The development of tapered roller bearings that can be used under high-speed conditions is accelerating. In the case of high-speed bearings, factors such as centrifugal force, gyroscopic moment, and slippage have a greater influence on the performance of the bearing, unlike the traditional operating mechanisms. The resulting lubrication characteristics have a profound impact on the failure mode of the bearing. In particular, unlike traditional roller bearings, system failure due to damage to the retainer frequently occurs, suggesting the need for prompt investigation. In this study, the rotational characteristics and strength of three models, a steel cage and two plastic cages for tapered roller bearings with the same internal structure, were examined. A comparative analysis of retainers with different shapes and materials can reveal the factors contributing to optimal performance under high-speed operating conditions and the optimal design of bearings.

In this study, the design for additive manufacturing of shoe molds with complex and precise patterns was performed to achieve rapid prototyping. Low alloy steels such as AISI4340 and SAE1524 were selected to make shoe molds to apply to the conventional chemical etching process. A lattice-oriented design and optimization of toolpath was tested to reduce the processing time. A reduction of 60% in processing time and pattern precision of 0.3 ㎜ was been achieved. Moreover, to improve the reliability of pattern formation, single-layer image analysis with computer vision and machine learning was developed and non-destructive analysis by X-ray CT was been performed. It was found that the quality of shoe molds can be decreased with a single defective layer.

Research on the automation of many types of construction equipment, including motor graders, is being actively conducted. In a motor grader cabin, the operator has difficulty observing the working environment because of a constructed field of view. Thus, workers rely on their experience and senses. Further, the working environment of the blade must be observed, and a control algorithm should be created to enable autonomous operation. In this study, a blade rotation control strategy considering the soil distribution was proposed. First, a co-simulation environment was constructed using RecurDyn for multibody dynamics analysis and EDEM for discrete element method simulation, and simulations were performed to determine the correlation between soil distribution and the blade rotation angle. Work quality and blade load were analyzed according to the simulation results. The optimal blade rotation angle according to soil distribution was obtained to develop the strategy for autonomous flattening and scattering work. The proposed control strategy was implemented in a 1/4 full-scale motor grader experimental setup. An experiment to evaluate work quality was conducted to validate the effectiveness of the proposed methods. The experimental results indicated that the proposed strategy effectively performed scattering work.

The automobile horn system is an essential part that produces sound for safety reasons. Production of horn system is classified based on two main processes. One of them is the caulking process which makes body assembly and forms the lower part of the horn system. The control dimension of body assembly is a crucial factor for quality control as the sound of the horn is largely determined by the control dimension. In this paper it has been found that plastic deformation of body and its restoration after caulking process is the main reason for the change in control dimension. Typically, 100 specimens of the body assembly were employed and the results were compared (Restore the Length of the Body) with another data set that had the same body but different parts in the assembly. Monte carlo simulation was used for tolerance analysis of control dimension for the body assembly including the deformation of the body in the caulking process. The simulation was identified as a good model to predict the satisfaction ratio of the control dimension with high accuracy and was observed to be useful in designing parts of the assembly and equipment used in the caulking process.

This research aims to provide a useful algorithm for the prediction of the geometrical expansion of flat rings in the radialaxial ring rolling process in case of multiple variations of the mandrel feeding speed during the process. The proposed algorithm was subjected to a 2-phases validation process, where results were compared with those of laboratory experiments, conducted at 150℃ on rings made of AA-1070 and AA-6061 aluminum alloys, and with numerical simulations, considering 7 different rings with outer diameter ranging from 800 to 2000 ㎜ and made of 42CrMo4 steel alloy, Ti6Al4V titanium alloy and AA-6061 aluminum alloys. In the first and second validation phases, the maximum deviation in the estimation of the outer diameter of the ring has been calculated in 1.7% and 6.82%, respectively. According to the results of the validation, the proposed algorithm is able to properly predict the geometrical expansion of the ring for multiple variations of the mandrel feeding speed during the process and has good accordance with both relatively small and large rings.

The mold manufacturing is one batch production that the same process does not repeat. The digital model in software is processed with a real mold fabricated in high performance without error. In this study process planning, and machining simulation software are integrated with a smart machine tool for the mold industry. It reduces the operational complexity to four button clicks after dragging and dropping of 3d model data to fabricate multiple-numbers of graphite electrodes. The smart machine tool fabricated 27 graphite electrodes with minimum interference of humans in 35 hours.

An integrated simulation program for virtual laser ablation is developed to help understand and predict the effects of machining parameters on the final machined results. The main solver of the program is based on the model for polymer ablation with short-pulse Excimer lasers. The GUI of the program is built using Visual Fortran and OpenGL so that the user can work in a visual environment, such as Windows on a PC, where the important machining parameters can be input via a dialog box and the calculated results for the machined shape can be plotted by means of a 3D graphics window using OpenGL. The developed GUI can be implemented for use with most pre-developed FORTRAN solvers for Windows application, allowing the user to control the input parameters and to see the results in a 3D plot; hence most FORTRAN users could create their own visual programs on PC Windows systems similarly, widening the range of application of FORTRAN solvers.

Structural pipe frames are usually manufactured by complex processes, in which a straight pipe with an arbitrary crosssection is prepared via a roll-forming process and then fabricated into three-dimensional shapes by a secondary process. These conventional processes have low productivity. Recently, the inefficiency of the conventional processes has created the need to develop new forming technologies. In this study, a new incremental roll-forming process is proposed. The study is aimed at verifying the feasibility of the proposed process and investigating the fundamental process parameters using finite-element simulations. The result of the simulation demonstrates that the proposed process can be used effectively for cold fabrication of various shapes of structural pipes. In addition, the result of the investigation of parameters shows that the forming amount, number of roll sets, and distance between roll sets are significant factors to be considered in resolving dimensional errors of the product and improving its quality.