• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2005년도 추계 학술논문 발표대회
• /
• pp.25-28
• /
• 2005

This study investigates the field application of surface insulation curing method, which combined double layer bubble sheet(DBS) and thick-curing-material(TCM) for cold weather concreting. According to the test, deck slab, curing only upper section with DBS and TCM, does not make big different temperature history with that, curing both upper and bottom section during daily average temperature 6.5t. It is concluded that combination of DBS and TCM in only upper section can be safely cured in early period of time during cold water concreting. The field test was carried out with this favourable data. The upper deck slab was insulated by combination of DBS and TCM, and the construction was surrounded by tent. in order to protect from outside wind. The test result shows that the lowest temperature of deck slab indicated 6$ ^{circ}C $. It demonstrated that this curing method can resist early frost and save construction cost in the side of management and saving labor cost, compared with previous method. In addition, the column specimen, combined both form and bubble board, exhibited favorable temperature history, due to internal hydration heat insulation effect.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2005년도 동계학술발표대회 논문집
• /
• pp.517-522
• /
• 2005

A cold storage refrigerator using phase change material(PCM) has been developed and its performance test results are provided here. The inner temperature of the refrigerator is controlled with forced convection driven by a fan using a DC battery. At the first, to freeze all the PCM of the ambient temperature by a built-in refrigerating machine, it took about 8 and 10 hours respectively at the refrigerator and the freezer mode. Then, without external power supply, the inner temperature of the cold storage refrigerator has been maintained at $-18{\pm}1^{\circ}C$ during 14 hours at the freezer mode and maintained at $3{\pm}^{\circ}C$ during 34 hours at the refrigerator mode. Just after the end of its valid usage as a refrigerator or a freezer, it took about 6 hours to refreeze the PCM for its reuse. During the test, the ambient temperature was kept at $30^{\circ}C$.

• 기본간호학회지
• /
• 제6권3호
• /
• pp.452-463
• /
• 1999

This study was performed to inquire into recognition of cold and heat application. The subjects in the study were 429 adults who were collected by disproportional quota sampling according to age, sex. The instrument was 36 questions that constitured closed questions and semiopened questions that encluded general characteristics, recognition of cold and heat applications. and what will you do when requested cold and heat applications on abdomial and perineal areas. Data were collected from september 25 to October 25, 1998. Data was analysed by SPSS/win, into frequency, Pearson correlation, t-test, ANOVA. The results were following. 1) The subjects consisted of male and female who was from teenage to fifty year old above. According to general characteristics, who endureed moderate cold-heat application, had constitutional fever, good sweat, and taked a cold bath accationally. And the woman think that their body were more cold than man. and the number of cold bath was less than man. Woman felt more harder than man that endured exposing cold. According to the recognitions of cold-heat applications, the 61.9% of the subjects think that cold application is more positive, and the 61.7% of the subjects think that heat application is more positive. 2) The subjects think that oral cavity, abdomen, back, extremes must be warm. 3) The percents of cold or heat application at abdomen were 77.4%, 86.5% respectely and the percents of cold or heat application at perineum were 56.9%. 93.6% respectely. With the above results. we know that the subjects have the fixed perceptions that each body part has to maintain its temperature. especially, they think that postpartum care is correlated with cold-heat application. So when we intervent nursing care, we also must regard their recognitions of cold and heat applications. and we need to educate and explain correctly about cold-heat application.

• 한국산학기술학회논문지
• /
• 제13권1호
• /
• pp.14-20
• /
• 2012

본 논문은 냉간단조 연료펌프와 다이캐스팅의 연료펌프에 대해 성능 실험과 아세트산이 포함된 에탄올에 250시간 연료펌프를 구동하여 부식성에 대해 실험을 수행하였다. 성능실험을 수행한 결과, 냉간단조된 하부하우징과 다이캐스팅된 하부하우징으로 제작된 연료펌프의 성능은 동등한 수준이었다. 내부식성은 다이캐스팅된 하부하우징보다 냉간단조된 하부하우징이 더 우수하였으며, 냉간단조된 하부하우징이 다이캐스팅된 하부하우징보다 치밀한 조직을 가지고 있었다.

• Nuclear Engineering and Technology
• /
• 제49권1호
• /
• pp.124-133
• /
• 2017

In-vessel retention by passive external reactor vessel cooling under severe accident conditions is a viable approach for retention of radioactive core melt within the reactor vessel. In this study, a new and versatile coating technique known as "cold spray" that can readily be applied to operating and advanced reactors was developed to form a microporous coating on the outer surface of a simulated reactor lower head. Quenching experiments were performed under simulated in-vessel retention by passive external reactor vessel cooling conditions using test vessels with and without cold spray coatings. Quantitative measurements show that for all angular locations on the vessel outer surface, the local critical heat flux (CHF) values for the coated vessel were consistently higher than the corresponding CHF values for the bare vessel. However, it was also observed for both coated and uncoated surfaces that the local rate of boiling and local CHF limit vary appreciably along the outer surface of the test vessel. Nonetheless, results of this intriguing study clearly show that the use of cold spray coatings could enhance the local CHF limit for downward-facing boiling by > 88%.

• Steel and Composite Structures
• /
• 제42권3호
• /
• pp.315-323
• /
• 2022

Shear connectors are key elements that ensure integrity in a composite system. The primary purpose of a shear connector is to bring a high degree of interaction between composite elements. A wide variety of connectors are available for hot-rolled composite construction, connected to the beam through welding. However, with cold-formed members being very thin, welding of shear connectors is not desirable in cold-formed composite constructions. Shear connectors for cold-formed elements are limited in studies as well as in the market. Hence in this study, three different types of shear connectors, namely, single-channel, double channel, and self-tapping screw, were considered, and their performance assessed by the Push-out test as per Eurocode 4. The connection between channel shear connectors and the beam was made using self-tapping screws to avoid welding. The performance of the connectors was analyzed based on their ultimate capacity, characteristic capacity, ductility, and slippage during loading. Strength to weight ratio was also carried out to understand the proposed connectors' suitability for conventional ones. The results showed relatively higher initial stiffness and ductility for double channel connectors than other connectors. Also, self-tapping screws had a higher strength to weight ratio with low ductility.

• 한국도로학회논문집
• /
• 제16권4호
• /
• pp.21-33
• /
• 2014

PURPOSES: The purpose of this study was to break away from the workforce method using cold-mix asphalt mixtures and has a constant quality and has develop repair materials of pre-production asphalt-precast types. METHODS: The selection of the repair material was determined as the results obtained through physical properties of materials and the field applicability. In case of repair materials, values obtained through Marshall stability test & the dynamic stability test & retained stability test as well as the site conditions was considered. In case of adhesive, test results were obtained through examination of the bond strength(tensile, shear) and the field applicability of the adhesive was examined through combined specimens to simulate field applications. RESULTS : According to the results of laboratory tests, in the case of repair materials, Marshall stability and dynamic stability, retained stability of cold-mix reaction type asphalt mixture is the highest. In the case of adhesive, two-component epoxy-urea has a very high bonding strength(tensile, shear) was most excellent. According to the results of field tests, when epoxy-urea was excellent workability. Also, the repair body through actual mock-up test did not occur large deformation and fracture after 12 months. CONCLUSIONS : A suitable repair material is cold-mix reaction type mixture of asphalt-precast, a suitable adhesive is a two-component epoxy-urea.

• 드라이브 ㆍ 컨트롤
• /
• 제15권3호
• /
• pp.43-48
• /
• 2018

The hydraulic control valve, used in the CPB (cold-pad-Batch) cold dyeing system, passes through a pressurized material that absorbs the dye. The hydraulic control of the hydraulic control panel shall be driven in a uniform and precisely controlled manner, as it interferes directly with the dyschromatism. In this study, an acceleration test model was employed to verify the durability of the hydraulic control of the hydraulic control panel, which was manufactured by the scenic model, and the pre-roll angle was analyzed before the performance of acceleration test. Based on the change in the amount of deformation of the padder roll the durability of the padder roll was analyzed along with verification of the durability of the skin and the rubber coating in contact with the fabric. Furthermore, the accelerated test method used for hydraulic controlled multi-cell padder rolls was verified.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
• /
• pp.1011-1015
• /
• 2017

본 연구에서는 고공환경을 모사하는 축소형 상온 시험에서의 노즐 유동에 관한 수치적, 실험적 연구를 진행하였다. 이론 계산에서는 노즐 출구의 온도가 액화점보다 낮게 계산이 되어 유체가 상변화 지점에서 존재하게 된다. 또한 수치해석 결과 이론 계산보다 높지만 액화되는 온도보다는 낮았다. 실제 환경에서의 검증을 위하여 상온 시험을 한 결과 이론과 해석보다는 월등히 높은 온도로 확인되었다. 이는 이론 계산 시 단열이라고 가정을 하며 문제를 풀지만 실험은 단열이 아닌 외부와의 열 교환이 일어나게 된다. 결과적으로 상온 시험 할 때에 상변화 지점보다 높은 온도인 것을 확인하였다.

• 한국압력기기공학회 논문집
• /
• 제17권1호
• /
• pp.49-55
• /
• 2021

In this paper, an application example for fitness-for-service of material is shown. A kind of instrument valve is made of austenitic stainless steel fabricated by the cold working process. The tensile strength of the cold worked austenitic stainless steel has to be limited under 90 ksi to prevent the stress corrosion cracking in power plants. In industrial fields, tensile strengths of some materials were discovered to be over the regulation requirements in a certified material test report (CMTR). Owner's verification tests were performed to compare with that in a CMTR and to check the appropriateness. It is found that, in the case of verification test under the required test speed, valve materials could be used in the field. Although it is only one application sample of material check process in the power generation site, this case study could show an importance of basic experimental technology in academia and research circles.