In recent years, the globalization has raised the interest in the overseas experiential learning. Overseas experiential learning has been playing an important role by learning from various cultures which enables the students to achieve the global insights and leadership. However, the regulations have not been properly established, and Ministry of Education tend to recommend not to travel abroad without a special purpose. The results were found that teachers seek the exchange program with the local students in the partner country, and, overall, the cost-effectiveness was relatively low. Also, with the fact that the revisit was not recommendable, the satisfaction of the previous activities has been questioned. Teachers agreed with the critical points on career development of middle school and high school students, and positively rated the suggested prototype of oversea experiential learning based on career education.
The air brake chamber is needed higher sealing performance and durability for the safety and confidential operation, especially, in brake systems of commercial vehicle. For higher sealing, we applied new clamping technique differentiated methods of other global manufacturers. And we developed the power spring and spring guide made from light engineering plastic with high durability in repeated condition. We also have achieved the basic performance test like sealing test in compressed air and various environment tests in dust and salty water for new manufactured air brake chambers. As a result, the air brake chamber applied light weight and high durable power spring is satisfied all demand specification conditions for commercial vehicle
본 연구의 목적은 1인승 보트를 설계·제작하여 시운전 및 전산유체역학(CFD)를 이용하여 속도성능을 분석하는 것이다. 선형설계를 포함한 보트의 전반적인 설계과정을 설명하였고, 설계를 바탕으로 제작된 보트에 대하여 잠잠한 해상에서 시운전을 수행했다. 시운전을 통해 보트의 설계속도에서 제동마력은 1680 W가 계측하였다. 유동해석은 상용 CFD 코드인 STAR-CCM+를 이용하여 자유수면과 동적트림을 고려하여 수행되었다. 유동해석 결과 잉여저항 성분이 마찰저항 성분에 비해 크게 나타나는 것을 확인할 수 있었다. 시운전과 CFD 결과를 바탕으로 보트의 전체효율계수를 추정하였다. 전체효율계수는 전달효율과 준 추진효율로 나누었다. 준 추진효율은 동일 프로펠러를 사용하는 솔라보트의 속도성능 추정 시 사용될 수 있다. 연구결과은 향후 개발될 보트의 선형설계, 성능 분석 및 개발에 정보를 제공할 수 있다.
Within aging rotary painting system for plastic wheel cover, sprayed paint particles caused the quality problem as attached to back surface of the wheel cover by the cyclone vortex in the booth. The purpose of this study is to select the spray conditions to ensure a stable quality of the rotary painting system. For this, simulation for flow characteristics of each spray nozzle have been carried out using ANSYS program, and tested to find the optimum spray condition, such as spray distance, spray pressure and rotation speed by manufactured test apparatus of paint spray. Finally, satisfactory results were obtained by testing with a actual painting system in developed spray conditions.
Electro-accel pedal is needed to raise fuel efficiency by controlled pedal angle signal regardless driver’s willings to fast start or stop pedaling, and to reduce muscle fatigue by designed Ergonomic structure. For this purpose, in this study, we designed new mechanism of accel pedal in a double linkage with two springs to minimize the force of pedaling on main pedal period for HECV in close the future. We have achieved the simulation to dynamic characteristics and experimented to measure the pedal force with proto sample, and confirmed the potentialities this new mechanism.
Air Brake chamber is a core fucntional part delivering the brake force to drum brakes in hybrid commercial trucks. This part needs to have leakage prevention and durability for reliable operation. As an actuator by air pressure, there has to be no air leakeage, and because it is operated with high tention power spring, there has high durable spring head, that contacted power spring directly. In this study, a spring head was designed new size on weak points structually and simulated by structual simulation program. And, a flange and body tighten by clamp ring was simlated structual deformation by assembly torque and inner pressure. As a result, new desgned spring head has structual stablilty over 1.7~14.7% and deformation is in proprotion to inner pressure but the assembly torque of clamp ring is not related to deformation.
As fires have frequently occurred with large scale at cultural assets and warehouses, the development of Korean type demolition fire apparatus for efficient fire fighting becomes important. In this study, structural stability is investigated for assembly model of boom and outrigger by using computational structural analysis. Analysis results of boom and outrigger unit are also compared with assembly model. As this study result, equivalent stress result of boom unit is about 6% higher than assembly model and equivalent stress result of outrigger unit is about 15% higher than assembly model.
주된 도시들의 불투수성 포장화에 따른 현상으로 토양의 사막화를 일으키고 있으며, 나아가, 도시 온난화 현상을 발생시켜 도시지역의 평균 온도를 올리는 원인이 되고 있다. 이로 인해 우수가 투수성 토양에 흡수되거나 잔류되어야 하는 양이 줄어듦에 따라 자주 도심지내에서 범람이 되는 현상을 보여주고 있다. 결국은 우수시스템이 제대로 작동하지 않고 침식이 발생하고 있다. 투수성 포장시스템과 관련해서는 블록 포장이 여러 군데서 수년 동안 사용되어 왔다. 또한 투수성 블록 포장은 전통적으로 사용된 아스팔트 포장 및 콘크리트 포장에 비해 다양한 형태로 사용될 수 있는 장점과 더불어 타 포장보다 미적으로 낳은 면을 보여 주고 있다. 따라서 도로의 현장 조건을 모사하기 위해 본 연구에서는 실험용 슬러지 및 휠 트래킹 장비를 이용한 블록 포장의 기능적인 투수성 평가를 실시하였다.
This study was aimed at evaluating the antifungal potentials of twelve plant extracts (Terminariae Fructus, Glycyrrhizae Radix, Cinnamomi Cortex, Taraxacum Platycarpum, Rubi Fructus, Caesalpiniae Lignum, Myristicae Semen, Caryophylli Flos, Sanguisorbae Radix, Alpiniae Katsumadaii Semen, Scutellariae Radix, Astragalus membranaceus) in preventing storage rot symptoms in ginger (Zingiber officinale). Samples were collected from ginger that had been stored for 120 days at 10-12 . A total of ten fungi were isolated from stored non-spoiled and spoiled ginger and identified using internal transcribed spacer gene sequencing as Hypocrea virescentiflava, Fusarium oxysporum, Acremonium strictum, Fusarium solani, and Cadophora fastigiata. The causal fungus of storage rot was identified as F. oxysporum by pathogenicity test. Twelve candidate plant extracts were screened for antifungal activity against F. oxysporum isolated from spoiled ginger by using the disk diffusion method. In minimal inhibitory concentration (MICs) test, all ethanolic extracts of Cinnamomi Cortex, Taraxacum platycarpum, and Caryophylli Flos exhibited higher antifungal activity against F. oxysporum than other plant extracts. The MIC value of Cinnamomi Cortex and Caryophylli Flos were determined to be 10 ìg/disc. The MIC of T. platycarpum, 2.5 ìg/disc, was the lowest. Based on the results, it was concluded that Cinnamomi Cortex, T. platycarpum, and Caryophylli Flos have potential to serve as effective treatments to prevent storage rot of ginger.
The quality and shelf life of sliced root of Platycodon grandiflorum (Doraji) treated by ozon-microbubble-heat shock (OMH) were investigated by combining modified-atmosphere packaging [MAP, (50% O2+15% CO2+35% N2)]. The study was based on microbiological (total viable bacteria, fungi, Enterobacteriaceae and coliforms numbers), physicochemical and sensory changes. OMH treatment was effective in reducing microbial populations of the sliced Doraji, especially Enterobacteriaceae and coliforms reduced by 2 log CFU/g. However OMH-MAP treatment remained the aerobe and fungi numbers. Regarding the color, OMH-MAP delayed the change of Hunter b* and the sliced Doraji by OMH-MAP treatment exhibited lower decrease of flavor and overall acceptability compared to those by polypropylene packaging after tap water treatment (Control). The OMH and 50%O2+15%CO2 MAP treatment gave better sensory quality and extended shelf-life for sliced Doraji (~3 days longer shelf-life than Control). Flavor was significantly related to overall acceptability at both Control and OMH-MAP, whereas total coliforms prevalence was associated with overall acceptability at only OMH-MAP. Therefore microbubble-heat shock treatment may improve microbial safety and sliced Doraji by OMH treatment can stored under 50%O2+15%CO2 treatment for up to 7 days. Thus, OMH and MAP treatment may be used in maintaining the storage quality and marketability of sliced Doraji.
In 2011, neighborhood parks occupied a total area of 280,135,257m2 in small and medium sized city areas and this excluded the metropolitan regions. In the rural area, the park area per person(22.64m2) is larger than the urban area(9.50m2). It is a questionable why there is a higher park ratio in the rural area compared to the cities, where the function of the neighborhood parks is not being utilized well. But, there are already a lot of parks that has been constructed in the rural areas and a lot of money is being spent in maintaining them. Hence, rather than reducing the number of "country parks", it can be suggested that these "country parks" ought to be utilized in a different manner than the parks in the city. In that point of view, this study examined the issues of the country park usage along with the utilization of the local festivals within the parks. Firstly in this context, this study compared the amount of neighborhood parks between small and medium sized cities and metropolitan areas, and analyzed those results. Secondly, daily newspaper articles were collected and categorized to find the usage of the rural park which were then analyzed. Then, the extraction of the essential points in composing the festival space was carried out. Also, the general design guides of making the neighborhood parks were drawn. Last but not least, using these two resources, this study suggested design guidelines for using neighborhood parks as a Festival Space in small and medium sized cities.
Discharge data examine the process of hydrologic cycle and used significantly in water resource planning and irrigation and flood control planning. It makes high quality discharge data, they carry out research on standard and method of discharge measurement, and equipment improvement. Now various flow meters are utilized to make discharge data in Korea. However, accuracy of equipment and exprerimental research data from measurement are not enough. ADCP(Acoustic Doppler Current Profiler) have been introduced and utilized for flow measurements since the end of 1980’s.
ADCP flow method is a formal method for flow measurement can easily applyd to relatively large rivers gradually recognized. This equipment can measure the non-contact three-dimensional velocity and water depth data very quickly and efficiently. Also, spatial and temporal resolution of the data is more accurate than any other flow measurement methods which measure flow rate by velocity - area measurement method.
In this paper, the velocity is measured using various flow meter and verified the effectiveness by applying from the ADCP in Geum-river. Various flow meters which are med for discharge measurements are VALEPORT002 , FLOW TRACKER, PRICE AA and ADCP. The average of five times flow measurement result by ADCP was 10.412 ㎥/s, with a standard deviation of 0.68.
The repeat test by ADCP and comparison between ADCP and other flow devices to verify the most import factor, flow measurement accuracy. In the result, repeat test of the ADCP showed similar values, flow values were similar to other velocity device results and the average error is 7.7%.