• Advances in materials Research
• /
• 제12권1호
• /
• pp.43-65
• /
• 2023

Free vibration analysis of power law and sigmoidal sandwich plates made up of functionally graded materials (FGMs) has been carried out using finite element based higher-order zigzag theory. The present model satisfies all-important conditions such as transverse shear stress-free conditions at the plate's top and bottom surface along with continuity condition for transverse stresses at the interface. A Nine-noded C0 finite element having eleven degrees of freedom per node is used during the study. The present model is free from the requirement of any penalty function or post-processing technique and hence is computationally efficient. The present model's effectiveness is demonstrated by comparing the present results with available results in the literature. Several new results have been proposed in the present work, which will serve as a benchmark for future works. It has been observed that the material variation law, power-law exponent, skew angle, and boundary condition of the plate widely determines the free vibration behavior of sandwich functionally graded (FG) plate.

• 한국분무공학회지
• /
• 제28권3호
• /
• pp.143-149
• /
• 2023

Amidst the drive towards carbon neutrality, interest in renewable synthetic e-fuels is rising rapidly. These fuels, generated through the synthesis of atmospheric carbon and green hydrogen, offer a sustainable solution, showing advantages like high energy density and compatibility with existing infrastructure. The physical properties of e-fuels can be different from those of conventional gasoline based on manufacturing methods, which requires investigations into how the physical properties of e-fuels affect the fuel injection characteristics. This study performs a comparative analysis between conventional and Fischer-Tropsch (F-T) synthetic gasoline (e-gasoline) across various fuel temperatures, including the cold start condition. The fuel properties of F-T synthetic and conventional gasoline are analyzed using a gas chromatography-mass spectrometry technique and the injection rates are measured using a Bosch-tube injection rate meter. The F-T synthetic gasoline exhibited higher density and kinematic viscosity, but lower vapor pressure compared to the conventional gasoline. Both fuels showed an increase in injection rate as the fuel temperature decreased. The F-T synthetic gasoline showed higher injection rates compared to conventional gasoline regardless of the fuel temperature.

• Journal of the Korean Wood Science and Technology
• /
• 제51권5호
• /
• pp.381-391
• /
• 2023

Densification is a technique used to improve biomass quality in wood pellet manufacturing and torrefaction treatment. In this study, the effects of torrefaction on the quality of Calliandra wood pellets were investigated, and pellets of Calliandra wood (Calliandra calothyrsus) and bark were evaluated. The study was conducted using a completely randomized design with two treatment factors, namely torrefaction temperature (250℃ and 300℃) and torrefaction duration (30, 45, and 60 min). The results showed that the interaction between temperature and torrefaction duration significantly affected the compressive strength, proximate value, and calorific value of the torrefied Calliandra wood pellets. An increase in the temperature and torrefaction duration decreased the compressive strength, moisture content, volatile matter content, and ash content of the torrefied Calliandra wood pellets. Conversely, the calorific value of Calliandra wood pellets increased with increasing temperature and torrefaction duration. The best-quality Calliandra wood pellets were produced at a torrefaction temperature and duration of 300℃ and 60 min, respectively. In terms of important quality parameters, ash content of 0.90% and calorific value of 6,303.80 cal/g were observed, which complied with the quality standards of Indonesian National Standard 8675:2018 and Deutsche Industrie Norm 51731.

• 국제학술발표논문집
• /
• The 1th International Conference on Construction Engineering and Project Management
• /
• pp.774-779
• /
• 2005

Client requirements is a concept with increasing interest in relation to several outcomes of companies, and in particular, in the event of apartment project that takes large share in the domestic construction industry, diverse angle of survey is performed to discover the client requirements and reflect them to the project to improve the quality. For this purpose, it is required to learn the client requirements and apply it in the apartment project, and the QFD (Quality Function Deployment) linked ROQ (Return On Quality) is a technique used in the manufacturing that surveys the client requirements to improve the customer satisfaction, and apply it to the quality improvement program to improve the profitability in this process. In this study, through the application of the ROQ process, the plan to improve the apartment quality management is presented. For this purpose, the consumer interview survey, FGI (focus group interview) survey and the client requirements are analyzed, and thereafter, through the interview with the specialist, the quality improvement program that enables the application to the product development of new apartment product is established. Through this process, the new apartment quality management improvement plan is presented.

• The Journal of Asian Finance, Economics and Business
• /
• 제9권5호
• /
• pp.365-376
• /
• 2022

This study aims to look into the causal relationships between corporate social responsibility and firm value, corporate social responsibility and institutional ownership, and firm value and institutional ownership. This study develops a triangle model of causal relationships among the three endogenous variables. Samples for this study are manufacturing companies listed on the Indonesia Stock Exchange for the period 2014-2018. The model is operated in the system of simultaneous equation models using the generalized method of moments technique to estimate parameter coefficients. After controlling the effects of trade-off/balancing capital structure and managerial ownership, the research findings show a positive causal relationship between CSR and firm value and firm value and institutional ownership. Institutional ownership has a positive effect on CSR, while the effect of CSR on institutional ownership is negative in the firms without managerial ownership and positive in the firms with managerial ownership. This study finds that the causal relationship between CSR and firm value is stronger after the trade-off/balancing of capital structure is included in the model. Capital structure has a convex effect on firm value and positively impacts institutional ownership. In addition, an independent commissioner has a negative impact on CSR but has no direct impact on firm value.

• 건축역사연구
• /
• 제32권3호
• /
• pp.77-88
• /
• 2023

In the late Joseon Dynasty, the floor of the royal palace was covered with grass mat called ji-ui. Ji-ui was produced by connecting several mats named seokja(席子) and trimming the edge with narrow fabric named seon(縇). The standard manufacturing technique was to connect the shorter sides of the seokjas by overstitching them. A room was covered with either single or multiple ji-uis, depending on the case. In the case of the main and the subsidiary halls (jeong-jeon and pyeon-jeon, respectively) where the king conducted official meetings with the civil servants, multiple ji-uis were laid out to signify the division of space, which reflected the ceremonial aspects of the governing acts. The most essential division was the distinction of yeong-wae(楹外) and yeong-nae(楹內), with the jeon-goju (a tall frontal pillar inside the hall) functioning as the breakpoint. Jeong-jeon was divided into four spaces each covered with one ji-ui: yeong-nae, yeong-wae, and the left and the right sides of the royal seat named jwa-tap(座榻). Pyeon-jeon was covered with three ji-uis that divided the hall into three spaces: yeong-nae, yeong-wae, and hu-twae(後退) (the hind section) where the royal seat was placed on.

• 한국초전도ㆍ저온공학회논문지
• /
• 제25권4호
• /
• pp.75-80
• /
• 2023

Rare earth barium copper oxide (REBCO) materials have shown the possibility of high-temperature superconductor (HTS) magnetic resonance imaging (MRI) magnets due to their elevated transition temperature. While numerous MRI magnet designs have emerged, there is a growing emphasis on estimating the cost before manufacturing. In this paper, we propose two designs of REBCO whole-body MRI magnets: (1) 1.5 T and (2) 3.0 T, the standard center field choices for hospital use, and compare their costs based on conductor usage. The basis topology of the design method is based on discretized solenoids to enhance field homogeneity. Magnetic stress calculation is done to further prove the mechanical feasibility of their construction. Multi-width winding technique and outer notch structure are used to improve critical current characteristic. We apply consistent constraints for current margins, sizes, and field homogeneities to ensure an equal cost comparison. A graph is plotted to show the cost increase with magnetic flux growth. Additionally, we compare our designs to two additional MRI magnet designs from other publications with respect to the cost and magnetic flux, and present the linear relationship between them.

• 무역학회지
• /
• 제46권5호
• /
• pp.153-171
• /
• 2021

The purpose of this study is to compare and derive the importance of motivating factors for start-up when deciding to start a business in the logistics and trading industries, and to compare, derive, and identify which motivating factors have an important influence on the start-up decision. In this study, 4 high-level factors such as career factors, policy/institutional factors, environmental factors, and economic factors and 12 low-level factors were derived from those four factors. Based on this, a questionnaire was distributed to established and prospective entrepreneurs, and the results were analyzed using the AHP (Analytic Hierarchy Process) technique. Manufacturing companies recognized the individual's capabilities and government support for them as important. Beside, service companies recognized the industrial environment that could generate economic benefits as important. Although there are differences in perception by group, it can be seen that factors that are recognized as important within each group have connectivity and show the same directivity.

• 한국IT서비스학회지
• /
• 제22권5호
• /
• pp.87-98
• /
• 2023

Traditionally, tooth restoration has been carried out by replicating teeth using plaster-based materials. However, recent technological advances have simplified the production process through the introduction of computer-aided design(CAD) systems. Nevertheless, dental restoration varies among individuals, and the skill level of dental technicians significantly influences the accuracy of the manufacturing process. To address this challenge, this paper proposes an approach to designing personalized tooth restorations using Generative Adversarial Network(GAN), a widely adopted technique in computer vision. The primary objective of this model is to create customized dental prosthesis for each patient by utilizing 3D data of the specific teeth to be treated and their corresponding opposite tooth. To achieve this, the 3D dental data is converted into a depth map format and used as input data for the GAN model. The proposed model leverages the network architecture of Pixel2Style2Pixel, which has demonstrated superior performance compared to existing models for image conversion and dental prosthesis generation. Furthermore, this approach holds promising potential for future advancements in dental and implant production.

• Tribology and Lubricants
• /
• 제39권6호
• /
• pp.244-249
• /
• 2023

This paper presents a comprehensive analysis of the impact of surface roughness on the friction and wear properties of SUS 321, an austenitic stainless steel variant produced using the laser powder bed fusion (LPBF) technique, which is a prevalent additive manufacturing method. After the LPBF fabrication, the specimens go a heat treatment process aimed at alleviating residual stress. Subsequently, they are polished extensively to achieve a refined and smooth surface. To deliberately introduce controlled variations in surface roughness, an etching process is employed. This multi-step method encompassed primary etching in a 3M hydrochloric acid solution, followed by secondary etching in a 35 wt% ferric chloride solution, with varying durations applied to different specimens. A comprehensive evaluation of the surface characteristics ensued, employing precise techniques such as surface roughness measurements and meticulous assessments of water droplet contact angles. Following the surface treatment procedures, a series of friction tests are performed to explore the tribological behavior of the etched specimens. This in-depth investigation reached its peak by revealing valuable insights. It clarified a strong correlation between intentionally altered surface roughness, achieved through etching processes, and the resulting tribological performance of LPBF-fabricated SUS 321 stainless steel. This significantly advances our grasp of material behavior in tribological applications.