• Advances in materials Research
• /
• 제13권3호
• /
• pp.183-194
• /
• 2024

D3 tools steel and 440C stainless steel (SS) are normally being employed for application such as knife blade and cutting tools. These steels are iron alloys which have high carbon and high chromium content. In this study, lab work focused on the microstructural and corrosion behavior of D3 tools steel and 440C SS after went through heat treatment processes. Heat treatments for both steels were started with normalizing at 1020 ℃, continue with hardening at 1000 ℃followed by oil quenching. Cryogenic treatment was carried out in liquid nitrogen for 24 hours. The addition of cryogenic heat treatment is believed to increase the hardness and corrosion resistance for steels. Both samples were then tempered at two different tempering temperatures, 160 ℃ and 426 ℃. For corrosion test, the samples were immersed in NaCl solution for 30 days to study the corrosion behavior of D3 tool steel and 440C SS after heat treatment. The mechanical properties of these steels have been investigated using Rockwell hardness machine before heat treatment, after heat treatment (before corrosion) and after corrosion test. Microstructure observation of samples was carried out by scanning electron microscopy. The corrosion rate of these steels was calculated after the corrosion test completed. From the results, the highest hardness is observed for D3 tool steel which tempered at 160 ℃(54.1 HRC). In terms of microstructural analysis, primary carbide and pearlite in the as-received samples transform to tempered martensite and cementite after heat treatment process. From this research, for corrosion test, heat treated 440C SS sample tempered with 426 ℃possessed the excellent corrosion resistance with corrosion rate 0.2808 mm/year.

• 재활치료과학
• /
• 제11권2호
• /
• pp.7-24
• /
• 2022

목적 : 아동 및 청소년의 다면적인 라이프스타일을 평가하는 표준화된 평가도구 개발을 위해 라이프스타일 평가도구와 라이프스타일 구성요소별 평가도구들을 체계적으로 분석하고자 한다. 연구방법 : 기간은 2001년부터 2020년까지였으며, 검색엔진은 CINANL, NDSL, PubMed, RISS를 사용하였다. 검색어는 'lifestyle assessment' OR 'lifestyle profile' OR 'lifestyle test', 'physical activity assessment' OR 'physical activity participation profile', 'nutrition assessment' OR 'nutrition profile', 'activity participation assessment' OR 'activity participation profile'을 사용하였다. 결과 : 5,883편의 연구에서 중복제거 후 제목, 초록, 전문을 검토한 결과, 총 24개의 평가도구가 선정되었다. 세부 결과로는 라이프스타일 평가도구 5개, 신체활동 평가도구 7개, 식습관 평가도구 9개, 활동참여 평가도구 3개가 도출되었다. 결론 : 아동 및 청소년의 라이프스타일 평가도구에 대하여 각 항목별 평가도구의 평가항목, 측정방법, 평가대상연령을 분석하였다. 향후 아동 및 청소년을 위한 표준화된 다면적인 라이프스타일 평가도구의 개발에 기초자료로 활용되기를 기대한다.

• Wind and Structures
• /
• 제27권2호
• /
• pp.71-88
• /
• 2018

At the University of Western Ontario (UWO), numerical tools represented in semi-closed form solution for the conductors and finite element modeling of the lattice tower were developed and utilized significantly to assess the behavior of transmission lines under downburst wind fields. Although these tools were validated against other finite element analyses, it is essential to validate the findings of those tools using experimental data. This paper reports the first aeroelastic test for a multi-span transmission line under simulated downburst. The test has been conducted at the three-dimensional wind testing facility, the WindEEE dome, located at the UWO. The experiment considers various downburst locations with respect to the transmission line system. Responses obtained from the experiment are analyzed in the current study to identify the critical downburst locations causing maximum internal forces in the structure (i.e., potential failure modes), which are compared with the failure modes obtained from the numerical tools. In addition, a quantitative comparison between the measured critical responses obtained from the experiment with critical responses obtained from the numerical tools is also conducted. The study shows a very good agreement between the critical configurations of the downburst obtained from the experiment compared to those predicted previously by different numerical studies. In addition, the structural responses obtained from the experiment and those obtained from the numerical tools are in a good agreement where a maximum difference of 16% is found for the mean responses and 25% for the peak responses.

• 대한기계학회논문집
• /
• 제9권2호
• /
• pp.190-201
• /
• 1985

본 논문에서는 측정된 공작기계의 동적성능은 절삭조건과 공작기계의 동적 컴 플라이언스의 복합적인 함수이므로 공작기계의 동적 성능을 정확히 평가하고 설계.개 선을 용이하게 하기 위하여는 직접절삭시험 중 가진 시험을 동시에 수행하는 방법이 필요하다. 본 연구에서는 선반의 외경 선삭가공중의 동적성능을 직접절삭시험과 가 진 직접절삭법을 통하여 평가하고자 한다.

• Journal of Information Processing Systems
• /
• 제1권1호
• /
• pp.75-78
• /
• 2005

Although many tests for stabilization of the software have been done, vulnerability test for a system run by combination of the software of various products has not been conducted enough. This has led to increased threats and vulnerability of system. Especially, web-based software system, which is public, has inherent possibility of exposure to attacks and is likely to be seriously damaged by an accident. Consequently, comprehensive and systematic test plans and techniques are required. Moreover, it is necessary to establish a procedure for managing and handling the results of vulnerability test. This paper proposes vulnerability test plans and designs for implementing automated tools, both of which can be complied with on web-based software systems.

• 한국산업융합학회 논문집
• /
• 제20권4호
• /
• pp.265-273
• /
• 2017

Major industries in Gyeongnam area include robot and automobile manufacturing, shipbuilding, and aviation. According to the research, the mechanical part of the products has been advanced, but awareness over the improvement of quality of the software still lacks. The quality performance test presently conducted by the companies in Gyeongnam is mostly the manual performance test performed by the program manager. In order to systematize this and extend the range of using software testing tools, the current study intends to suggest the necessity for conducting a survey on demand to improve performance and securing testing tools such as measured data analysis. Accordingly, this study is going to investigate 33 companies in Gyeongnam related with software in each of the major business areas centering around the actual field and examine activities related to software quality. And after figuring out the current status of retaining testing tools, the study will suggest the ways to enhance recognition over software quality and propose ultimate solutions to solve the problems on the current stage by finding out how to share information as much as possible in order to lay the foundation for extending the range of activity for the sake of software quality.

• 한국항공운항학회지
• /
• 제29권3호
• /
• pp.24-33
• /
• 2021

Although it is the first transportation method to apply the 'Ground Effect' applied to aircraft to ships, WIG ships, which are classified as 'Ships' operating on the water under international law. The pilot aptitude test, which has the effect of preventing safety accidents in advance, has not yet been established as a legal system in S. Korea, after being certified by the Korean Register of Shipping (KR) for the first time in the world in March 2020. Therefore, the purpose of this study is to ensure that identifying the importance, recognition, correlation, etc. of the tools and items of aptitude testing, from a group of experts, can be used appropriately for future development of legal aptitude testing tools. As a method of study, the questionnaire method was used, and the analysis confirmed that the tools used on aircraft and ships could be used appropriately. In particular, Due to the characteristics of the WIG ships, it was confirmed that it is necessary to develop more specifically in the future, the operational qualifications and physical fitness items, which are the aptitude evaluation items.

• Geomechanics and Engineering
• /
• 제13권1호
• /
• pp.119-139
• /
• 2017

Static Penetration Test (CPT) and Dynamic Penetration Test (DPT) are commonly used in-situ tests in a routine geotechnical investigation. Besides their use for qualitative investigation (lithology, homogeneity and spatial variability), they are used as practical tools of geotechnical characterization (resistance to the penetration, soil rigidity) and modern foundation design as well. The paper aims at presenting the results of an extensive research work on the evaluation of the 1D primary consolidation settlement of saturated clayey soils on the basis of the CPT or DPT tests. The work is based on an analysis of the correlations between the tip resistance to penetration measured in these tests and the parameters of compressibility measured by the compressibility oedometer test, through a local geotechnical database in the northern Algeria. Such an analysis led to the proposal of two methods of calculation of the settlement, one based on the CPT test and the other one on the DPT. The comparison between the predicted settlements and those computed on the basis of the oedometer test showed a good agreement which demonstrate the possbility to use the CPT and DPT tests as reliable tools of computation of foundation settlements in clayey soils.

• 대한물리의학회지
• /
• 제12권3호
• /
• pp.49-58
• /
• 2017

PURPOSE: To summarize the evaluation tools of balance [Berg Balance Scale (BBS), timed up and Go (TUG), forward reaching test (FRT)], gait [6 m walking Test (6MWT)], and strength [Chair Stand Test (CST)] for patients with dementia. METHODS: The following databases were searched: Pub MED, Cochrane, Sciences Direct, and Web of Sciences. The inclusion criteria were as follows: 1) repeated measurement design, 2) subjects with dementia, 3) use of testing tools such as the BBS, TUG, FRT, 6MWT, and CST, 4) report the reliability. One reviewer performed the quality assessment of diagnostic accuracy study and two evaluators performed data extraction independently. RESULTS: Six articles and one letter were included. The interrater reliability of 6MWT, TUG, and CST, were acceptable (ICC>.90). However, FRT had unacceptable reliability. In test-retest reliability, only BBS has acceptable reliability (ICC>.90). Others had various reliabilities. The risk of interrater reliability bias was low in all studies. However, the risk of bias of intrarater reliability was low in five studies and moderate in two studies. CONCLUSION: The interrater reliability of the 6MWT, TUG, and CST were acceptable. However, in test-retest reliability, only BBS has acceptable reliability. Therefore, we suggest the use of BBS to test the balance of dementia patients. In addition, the study of tool reliability according to the subtype of dementia is needed in the future.

• 소성∙가공
• /
• 제26권3호
• /
• pp.137-143
• /
• 2017

In this study, a wear test method was proposed to predict the wear life of the CrN layer coated on the surface of the press tools for manufacturing the auto-parts with ultra high strength steel (UHSS) with a tensile strength of 1.5 GPa. The pin-on-disc type wear test was carried out to confirm the feasibility and the reproducibility of the wear amount according to the test conditions such as the normal force, the sliding velocity, and the sliding speed. The test conditions were obtained from the finite element stamping analysis and the wear simulation. With the wear amount from the wear test, a prediction model of the wear depth in the CrN coating layer was proposed according to the test conditions with the design of experiments such as Taguchi method and the response surface method. The derived prediction model was then compared to the result of the Archard wear model, fully describing that the proposed model can effectively predict the wear life of the press tools for the auto-parts with UHSS.