• Journal of the Korea Institute of Military Science and Technology
• /
• v.6 no.4
• /
• pp.113-123
• /
• 2003

Both numerical analysis and experiment of cold and hot tests were performed to obtain basic design data for the swirl coaxial type Injector and to predict the combustion performance. Mass distribution, mixing distribution, mixing efficiency, characteristic velocity efficiency were measured by the cold tests and numerical analysis using the commercial thermo-hydraulic program. Test and analysis variables were recess, pressure drop, velocity ratio, mixing spray, mixture ratio. Hot tests were performed for the Uni-element injector to compare the performance with the cold test results, and, hot tests for Multi-element injector were performed to compare the performance with Uni-element injector. Designed thrust of the Uni-element injector liquid rocket was 35kgf at sea level and combustion chamber pressure, 20bar. Kerosene and Lox were used as a propellant.

• Korean Journal of Child Studies
• /
• v.21 no.2
• /
• pp.83-97
• /
• 2000

Ninety 6th graders were randomly assigned to an experimental or a control group in this 5 week study of the effects of constructivist instruction on writing performance. After the writing pre-test, the experimental group was treated with constructivist instruction while the control group was treated with a tradition procedure based on Joyce and Weil's(1992) basic exercise model Instruction consisted of ten 40-minute sessions. The effectiveness of the constructivist instruction was tested by post-and retention-tests. Two raters scored the children's writing by the analytical scale of Jin-Suk Won(1994). Results were analyzed by t-test. The writing performance and the retention scores of the experimental group were higher than that of the control group. The results of the sub-criteria scores showed significant effects on children's understanding of contents and constructive performance.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.21 no.10
• /
• pp.1380-1391
• /
• 1997

A 150 m$^{3}$/hr, 30 kg/cm$^{2}$, air-cooled 3-stage reciprocating air compressor is designed to be used in starting large diesel engines. A basic design procedure is presented to meet the targeted pressure and flow rate, and especially the volumetric efficiency. Temperature and stress analyses of the cylinder are performed using FEM modelings. The dynamics of valve system is analyzed and stress at the valve seat due to valve impact is evaluated. To reduce friction loss and wear at the compressor engine system, tribological design practices are suggested. Fin-type coolers are designed to dissipate generated compression heat at each stage. Finally, a prototype is manufactured and performance test is carried out utilizing an air tank. Performance results are compared to the design targets, other foreign specifications, and some quality standards.

• Human Ecology Research
• /
• v.60 no.1
• /
• pp.131-145
• /
• 2022

The purpose of this study was to reveal the effects of sales services and organizational member relationships of fashion brand salespersons on job performance and job satisfaction, as well as how job performance, job satisfaction, salesperson services, and organizational member relationships differ according to the sales career and job position. The data were collected by administering a questionnaire to fashion brand salespeople in Gwangju from September to October 2020. Using 235 responses, the data were analyzed with SPSS 27.0 for frequency analysis, reliability analysis, t-test, factor analysis, and regression analysis. The research results were as follows. First, the basic services of the salesperson comprised factors such as 'consideration and convenience', 'appearance and dress', and 'kindness and greeting', which are considered better variables to explain job performance than job satisfaction. Second, the salesperson's professional service consisted of 'fashion product knowledge', 'professional self-management', and 'store display technology' factors, which are good variables to predict job performance. Third, the relationship between the members of a salesperson's organization consists of factors such as 'headquarters relations', 'colleague relations', and 'emotional labor', which was better for explaining job satisfaction than job performance. Fourth, depending on the position, professional salespeople exhibited significantly higher values in job performance, basic and professional services of salespersons, and 'headquarters relations' factors, whereas there were no significant differences in job satisfaction, 'colleague relations' and 'emotional labor'. Lastly, the more sales career, the higher the job performance, and the basic services, professional services, and 'headquarters relations' factors of salespeople were also good.

• Journal of Biosystems Engineering
• /
• v.43 no.4
• /
• pp.311-319
• /
• 2018

Purpose: The aim of this study is to develop a small combine for harvesting miscellaneous cereal crops. Methods: A prototype small combine was designed and constructed. Its specifications and basic performance were investigated. Results: The prototype small combine for harvesting miscellaneous cereal crops was designed and constructed to reflect similar specifications as those of the conventional combine. The prototype small combine comprises a diesel engine with the rated power/speed of 22.0 kW/2,600 rpm, three-stage primary and two-stage speed range transmission shifts, and a double acting threshing part. The maximum travel speeds of the prototype combine are approximately 0.72 m/s, 2.50 m/s, 0.30 m/s at the low, high speed range shifts in the forward direction, and while traversing in the reverse direction, respectively. The minimum radius of turning was approximately 1.50 m. In a static lateral overturning test, the prototype combine overturned neither to the right nor to left on a $30^{\circ}$ slope. The results of an oilseed rape harvesting test included the maximum operating speed of 0.32 m/s, the grain loss ratio of approximately 9.0%, and the effective field capacity of approximately 10.3 a/h. Additionally, among the outputs in grain outlet, the whole grains, damage grains, and materials other than grain (MOG) ratios accounted for 97.4%, 0.0%, and 2.6%, respectively. Conclusions: The prototype small combine for harvesting miscellaneous cereal crops indicates good driving ability and stability. The results of the oilseed rape harvesting test reveal that the harvesting performance must be enhanced such that the separating and cleaning parts are more suitable for each type of crop, thus reducing grain loss and foreign substances among the outputs in grain outlet. An improved small prototype combine could be used effectively to mechanize the harvesting of miscellaneous cereal crops in small family farms or semi-mountainous areas.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.04a
• /
• pp.17-20
• /
• 2008

To develop floor impact sound resilient materials of apartment house effectively, floor impact sound insulation performance test lab. was designed and constructed in T company. Introducing specification and basic performance of this lab. could be helpful in plan and design of another lab. Floor space size of this lab. is $4.2m{\times}5.5m$ and this size is similar with that of living room of usual apartment house's (about $100m^2$) and the height of lab. is 2.4m. Slab thickness is designed by 180mm. Frequency characteristics is similar to general apartment house. Reverberation time of sound receiving room displays 1.26sec in 125Hz by establishing sound-absorbing materials. For light weight impact sound insulation performance of concrete bare floor structure is estimated by $L_{i,AW}\;=\;73$ and for heavy weight is estimated by $L_{i,Fmax,AW}\;=\;50$. Sound pressure level distribution of sound receiving room is ranged very uniformly. With these results, floor impact sound resilient materials could be evaluated and the results could be trusted by comparison tests.

• Proceedings of the SAREK Conference
• /
• 2008.11a
• /
• pp.413-418
• /
• 2008

The toroidal field magnet power supply (TF MPS) for the KSTAR was constructed in August, 2007 and started the operation for the commissioning in March, 2008. The main role of the TF MPS is to supply the electric power to the TF magnet of the KSTAR. The water cooling components of the TF MPS are 16 stacks, busbar of 70 meters. For the cooling of the TF MPS, the D I water cooling system was designed and installed. The water cooling system consists of several pumps, heat exchangers, D I water polishing system and so on. The water cooling system for the TF MPS was tested under the 15 kA current charging condition. In this paper be discussed about the system performance and other parameters.

• Journal of Korean Institute of Architectural Sustainable Environment and Building Systems
• /
• v.12 no.6
• /
• pp.543-556
• /
• 2018

Zero energy building was attended for energy consumption minimization by the energy saving technology about building heating and cooling energy consumption and the renewable energy production facility. So the government has supported the zero energy building supply for decreasing green gas emissions. The study about inventory of zero energy building has many proceeding. That inventory need the information of material and equipment. So information of material and equipment about zero energy building must be included for the zero energy building realization. Actually the database of zero energy building inventory construction through the inventory established studies has difficult because the database need many information. In this study, author proposed the test methods and performance reference for upload at inventory. It was constructed to material - module - package. Also the author analyzed the construction of the technical package for zero energy building. The author separated performance category to the energy performance for energy analysis and other performance for confirmed the durability, stability and etc. This performance category proposed the table. The test methods of material and equipment in the passive package and active package proposed to the international standard and korea standard basically korea standard. Also the performance reference was proposed to korea legal standard and various standard by this study results. And the authors proposed the table of performance value, test methods, performance reference. By result of this study, the test methods and performance reference will be used the basic data for inventory of zero energy building.

• Journal of the Korean Society of Radiology
• /
• v.17 no.1
• /
• pp.71-77
• /
• 2023

The issue of North Korea's denuclearization is an global issue that transcends the North and South. It is necessary to prepare for the denuclearization process in preparation for the situation in which North Korea reveals its intention to denuclearize. In the process of North Korea's denuclearization, it is required to guarantee the normal operation of the denuclearization verification equipment. If a performance test criteria that takes into account the North Korean environment is established, it is highly likely that it will be used in the future denuclearization process. For this purpose, basic materials related to performance test standards were established through analysis of test standards such as international standards. After that, we established a performance test criteria. This includes high temperature, low temperature, humidity, vibration and shock tests. Through follow-up studies, validity of test criteria will be established through actual device testing.

• Physical Therapy Rehabilitation Science
• /
• v.12 no.3
• /
• pp.222-228
• /
• 2023

Objective: Training-related injuries and attrition put an additional burden on police and military institutions. Preventing and minimizing musculoskeletal injuries is the primary concern of the Abu Dhabi Police. Therefore, this study aimed to evaluate the correlation between functional movement screen, lower-limb strength, Y-balance test, grip strength and vertical jump and the incidence of musculoskeletal injuries among Abu Dhabi police recruits. Design: Observational analytical study. Methods: An observational study was conducted on 400 male police recruits of Abu Dhabi Police Academy. Physical performance was assessed before the 16-weeks basic police training. Spearman's correlation evaluated the correlation between the performance parameters and the outcome measures and logistic regression predicted the risk factors associated with musculoskeletal injuries. Results: 149 (34.4%) participants reported at least one injury during the basic police training. Comparison between injured and non-injured participants showed significant difference in mean right Y-balance, back-leg-chest dynamometer, and vertical jump (p=0.02, p=0.02, and p=0.04, respectively). Spearman's correlation showed a significant negative correlation between risk of injury and back-leg-chest dynamometer and right Y balance (ρ= -0.11, p=0.03). Logistic regression showed that back-leg-chest dynamometer and right Y balance were significant predictors of injury (p =.036 and p=0.037; Odds ratio=0.96; 95% CI (0.92, 0.99) and Odds ratio=0.99; 95% CI (0.98,0.99). Conclusions: Our findings suggest functional movement screen and grip strength may not independently predict injury rates, balance and lower-limb strength needs to be considered in injury prevention strategies to reduce musculoskeletal injuries.