• Nuclear Engineering and Technology
• /
• v.52 no.2
• /
• pp.223-229
• /
• 2020

The present work proposes a solution to the static Boltzmann transport equation approximated by the simplified P₃ (SP₃) on angular, and the analytic coarse mesh finite difference (ACMFD) for spatial variables. Multi-group SP₃-ACMFD equations in 3D rectangular geometry are solved using the GMRES solution technique. As the core time dependent analysis necessitates the solution of an eigenvalue problem for an initial condition, this work is hence devoted to development and verification of the proposed static SP₃-ACMFD solver. A 3D multi-group static diffusion solver is also developed as a byproduct of this work to assess the improvement achieved using the SP₃ technique. Static results are then compared against transport benchmarks to assess the proximity of SP₃-ACMFD solutions to their full transport peers. Results prove that the approach can be considered as an acceptable interim approximation with outputs superior to the diffusion method, close to the transport results, and with the computational costs less than the full transport approach. The work would be further generalized to time dependent solutions in Part II.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2004.04a
• /
• pp.443-449
• /
• 2004

In this paper, we established a simulation model for transport vehicle that carries the container transportation between apron and yard block on automated container terminal with a perpendicular yard layout. Usually, the efficiency of container terminal is evaluated by productivity of container cranes at apron, and though there are enough support of transport vehicles and yard cranes, can improve the productivity of container cranes. Especially, transport vehicle is very important factor in productivity of container cranes and has variable work productivity according to loading and unloading situation of container cranes. Therefore, a method that can estimate work productivity of transport vehicle efficiently is required. We analyzed work productivity of transport vehicle using simulation model that has state transition of transport vehicle. We performed various simulation experiment and analyzed work productivity of transport vehicle and calculated the required number of transport vehicle by container crane additionally.

• Safety and Health at Work
• /
• v.8 no.2
• /
• pp.175-182
• /
• 2017

Background: With the recent rapid industrialization, occupational safety and health (OSH) has become an important issue in all industrial and human activities. However, incidents of injuries and fatality rates in the Ghanaian industry sector continue to increase. Despite this increase, there is no evidence regarding the element of OSH management in transport activities in Ghanaian industries. Thus, this study aims to examine the perceptions regarding the importance of safety and health in work-related transport activities in Ghanaian industries. Methods: A survey data collection technique was used to gather information on best safety practices over a 5-month period. We randomly selected 298 respondents from industries to answer structured questionnaires. The respondents included drivers, transport managers, and safety engineers. Standard multiple regression model and Pearson product-movement correlation were used to performed the analysis. Results: The result shows that for interventions to improve safety and health, concentration has been on drivers' safety practice with less attention to safe driving environments and vehicle usage. Additionally, the respondents are aware of the importance of OSH in transport activities, but the level of integration does not measure up to the standard to reduce operational accidents and injuries. Finally, strong commitment to changing unsafe practices at all levels of operations appears to be the effective way to improve safety situations. Conclusion: OSH culture is not fully complied in industries transport activities. This study, therefore, supports the use of safety seminars and training sessions for industry workers responsible for transport operations for better integration of safety standards.

• Safety and Health at Work
• /
• v.9 no.4
• /
• pp.454-461
• /
• 2018

Background: Working conditions and psychosocial work factors have acquired an important role explaining the well-being and performance of professional drivers, including those working in the field of public transport. This study aimed to examine the association between job strain and the operational performance of public transport drivers and to compare the expositions with psychosocial risk at work of three different types of transport workers: taxi drivers, city bus drivers, and interurban bus drivers. Method: A sample of 780 professional drivers was drawn from three transport companies in Bogota (Colombia). The participants answered the Job Content Questionnaire and a set of sociodemographic and driving performance questions, including age, professional driving experience, work schedules, and accidents and penalties suffered in the last 2 years. Results: Analyses showed significant associations between measures of socio-labor variables and key performance indicators such road traffic accidents and penalties. Furthermore, multiple linear regression analysis contributed to explain significantly suffered accidents from key variables of the Job Demand-Control model, essentially from job strain. In addition, throughout post-hoc analyses, significant differences were found in terms of perceived social support, job strain, and job insecurity. Conclusion: Work stress is an issue that compromises the safety of professional drivers. This research provides evidence supporting a significant effect of job strain on the professional driver's performance. Moreover, the statistically significant differences between taxi drivers, city bus drivers, and interurban bus drivers in their expositions to work-related stress suggest the need for tailored occupational safety interventions on each occupational group.

• Fire Science and Engineering
• /
• v.28 no.4
• /
• pp.81-88
• /
• 2014

This study identified the complaint ratio of musculoskeletal symptom by 119 EMTs and investigated the work risk extent through ergonomics evaluation about the patient transport works, which cause work-related musculoskeletal disorders (WMSDs) to 119 EMTs. For this, the complaint ratio of musculoskeletal symptom utilized questionnaire tool based on KOSHA Code H-30-2008 and the risk extent about the patient transport work evaluated by using ergonomics evaluation tools such as OWAS, RULA and REBA. According to the study result, 60.9% of 119 EMTs experienced musculoskeletal symptom. Among them, the symptom on back was the most common (36.1%). The work, which mostly causes WMSDs, has been found as patient transport work (48.4%). Among the patient transport motion, loading/unloading of ambulance cot to/from ambulance and the lifting of patient by stretcher were OWAS risk-level 3 and RULA/REBA risk-level 3 to 4. Among the patient transport environment, carrying patient on stairway using emergency mini-stretcher, moving patient in vehicle using spine board and piggy-back carrying or cradle carrying patient on stairway or slope way were OWAS, RULA, REBA risk level 3 to 4. It is suggested that immediate improvement in work postures for these works should contribute to prevention against WMSDs to 119 EMTs.

• Journal of Biosystems Engineering
• /
• v.16 no.2
• /
• pp.159-166
• /
• 1991

A simulation model was developed for analyzing a crop transport system using SLAMSYSTEM. The developed model could predict total delivered amount and delivery rate of a crop under various conditions of transport and analyze the effects of work factors on the efficiency of the crop transport system. A simulation model was also developed to analyze a rice transport system based on the generalized model of the crop transport system.

• The Journal of Asian Finance, Economics and Business
• /
• v.7 no.9
• /
• pp.603-611
• /
• 2020

Higher education has long been considered as a means of human resource development in a nation. The faculty member plays a significant role in improving the quality of higher education. It is clear that job satisfaction and motivation have effect on the faculty member's performance. The objective of this study is to investigate the levels and factors affecting lecturers' motivation in Vietnamese public universities. In this study, ordinary least squares (OLS) and exploratory factor analysis (EFA) have been utilized to identify the factors affecting work motivation of lecturers at Vietnamese universities. A questionnaire was administered to a sample of 189 lecturers at different public universities in Vietnam. The finding indicates that seven factors including Work characteristics (WC), Wage and welfare (WW), Social recognition (SR), Peer relationships (PR), Training and promotion opportunities (PO), Leader caring (LC) and Teacher-student interaction and student's attitude (IA) have positive effect on lecturers' work motivation. Among these factors, Teacher-student interaction and student's attitude (IA) has the strongest impact with the coefficient of 0.631 and Peer relationships (PR) has the least impact on work motivation with the coefficient of 0.020. The study findings can facilitate the understanding of how to increase work satisfaction at the universities in Vietnam.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.21 no.12
• /
• pp.2196-2208
• /
• 1997

In this work, a magnetic levitation (maglev) system is developed to transport a wafer between semiconductor fabrication process modules in clean rooms to take advantages of eliminating particle and oil contamination that normally exist in conventional transport systems due to contact motion of mechanical components. A main feature of the maglev system developed in this work is that a controller and power supplying part are not mounted on the moving carrier but on the stationary track, which is defined a controller-free carrier, to reduce carrier's weight. Iron-core electromagnets and irons are used for levitation, and air-core electromagnets and permanent magnets are used for stabilization. Analysis, design, and modeling of the magnetically levitated transport system are presented. The performance of the maglev system is experimentally demonstrated.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.432.2-432.2
• /
• 2014

Recently, colloidal core/shell type quantum dots lighting-emitting diodes (QDLEDs) have been extensively studied and developed for the future of optoelectronic applications. In the work, we fabricate an inverted CdSe/ZnS quantum dot (QD) based light-emitting diodes (QDLED)[1]. In order to reduce work function of indium tin oxide (ITO) electrode for inverted structure, a very thin (<10 nm) polyethylenimine ethoxylated (PEIE) is used as surface modifier[2] instead of conventional metal oxide electron injection layer. The PEIE layer substantially reduces the work function of ITO electrodes which is estimated to be 3.08 eV by ultraviolet photoemission spectroscopy (UPS). From transmission electron microscopy (TEM) study, CdSe/ZnS QDs are uniformly distributed and formed by a monolayer on PEIE layer. In this inverted QD LED, two kinds of hybrid organic materials, [poly (9,9-di-n-octyl-fluorene-alt-benzothiadiazolo)(F8BT) + poly(N,N'-bis (4-butylphenyl)-N,N'-bis(phenyl)benzidine (poly-TPD)] and [4,4'-N,N'-dicarbazole-biphenyl (CBP) + poly-TPD], were adopted as hole transport layer having high highest occupied molecular orbital (HOMO) level for improving hole transport ability. At a low-operating voltage of 8 V, the device emits orange and red spectral radiation with high brightness up to 2450 and 1420 cd/m2, and luminance efficacy of 1.4 cd/A and 0.89 cd/A, respectively, at 7 V applied bias. Also, the carrier transport mechanisms for the QD LEDs are described by using several models to fit the experimental I-V data.

• Carbon letters
• /
• v.14 no.3
• /
• pp.162-170
• /
• 2013

The performance of graphene-based electronic devices is critically affected by the quality of the graphene-metal contact. The understanding of graphene-metal is therefore critical for the successful development of graphene-based electronic devices, especially field-effect-transistors. Here, we provide a review of the peculiar properties of graphene-metal contacts, including work function pinning, the charge transport mechanism, the impact of the process on the contract resistance, and other factors.