• Computers and Concrete
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• 제17권6호
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• pp.787-799
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• 2016

Climate anomalies in recent years, numerous natural disasters caused by landslides and a large amount of entrained sands and stones in Taiwan have created significant disasters and greater difficulties in subsequent reconstruction. How to respond to these problems efficaciously is an important issue. In this study, the sands and stones were doped with recycled materials (waste LCD glass sand, slag powder), and material was mixed for recycled ready-mixed soil. The study is based on security and economic principles, using flowability test to determine the water-binder ratio (W/B=2.4, 2.6, and 2.8), a fixed soil: sand ratio of 6:4 and a soil: sand: glass ratio of 6:2:2 as fine aggregate. Slag (at concentrations of 0%, 20%, and 40%) replaced the cement. The following tests were conducted: flowability, initial setting time, unit weight, drop-weight and compressive strength. The results show that the slump values are 220 -290 mm, the slump flow values are 460 -1030 mm, and the tube flow values are 240-590 mm, all conforming to the objectives of the design. The initial setting times are 945-1695 min. The unit weight deviations are 0.1-0.6%. The three groups of mixtures conform to the specification, being below 7.6 cm in the drop-weight test. In the compressive strength test, the water-binder ratios for 2.4 are optimal ($13.78-17.84kgf/cm^2$). The results show that Recycled ready-mixed soil materials (RRMSM) possesses excellent flowability. The other properties, applied to backfill engineering, can effectively save costs and are conducive to environmental protection.

• Journal of Advanced Marine Engineering and Technology
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• 제31권6호
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• pp.707-714
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• 2007

The heat transfer coefficient and Pressure drop during gas cooling process of $CO_2$ (R-744) in inclined helical coil copper tubes were investigated experimentally. The main components of the refrigerant loop are a receiver. a variable-speed pump. a mass flow meter, a pre-heater and a inclined helical coil type gas cooler (test section). The test section consists of a smooth copper tube of 2.45mm inner diameter. The refrigerant mass fluxes were varied from 200 to $600[kg/m^2s]$ and the inlet Pressures of gas cooler were 7.5 to 10.0 [MPa]. The heat transfer coefficients of $CO_2$ in the inclined helical coil tubes increases with the increase of mass flux and gas cooling pressure of $CO_2$. The pressure drop of $CO_2$ in the gas cooler shows a relatively good agreement with those Predicted by Ito's correlation developed for single-phase in a helical coil tube. The local heat transfer coefficient of $CO_2$ agrees well with the correlation by Pitla et al. However, at the region near pseudo-critical temperature. the experiments indicate higher values than the Pitla et al. correlation. Therefore. various experiments in the inclined helical coil tubes have to be conducted and it is necessary to develop the reliable and accurate prediction determining the heat transfer and pressure drop of $CO_2$ in the inclined helical coil tubes.

• 대한기계학회논문집
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• 제16권2호
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• pp.325-335
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• 1992

In this work, direct contact 4-stage fluidized bed heat exchanger is experimentally studied to develop a new type of heat exchanger which recovers the energy contained in the high temperature waste gas exhausted from the industrial furnaces. A sand is used as a heat transfer medium in this experiment. To determine the optimum operating condition, 11 different perforated plates which have a different free area ratio with different hole diameter are used in the experiment. From the room temperature experiment, the pressure drop which is caused by fluidized bed formation is observed. The high temperature experiment is carried out to seek the optimum operating condition of high heat efficiency at low heat exchanger operation cost. The results of experiment are as following. The pressure drop in the high temperature condition can be predicted from the results of the room temperature experiment. And Nusselt number becomes smaller due to the increased interference between sand particles as Reynolds number increases when the dilute phase fluidized beds are formed in nigh temperature condition. But heat transfer amount through the total sand surface area become larger due to the large resident amount of sand. Considering the heat transfer amount and the heat exchanger operation cost, perforated plates which have either a 30% or 35% of free area ratio with 15mm of hole diameter are best fitted for our goal of this work. The values of .phi. which is a dimensionless number representing the absorption heat amount per unit sand rate are in the range from 0.4 to 0.5, when Reynolds number of waste gas ranges from 25-30 with these perforated plates.

• 한국운동역학회지
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• 제24권4호
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• pp.375-383
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• 2014

The purpose of this study was to assess the inter-segmental trunk motion during which multi-segmental movements of the spinal column was designed to interpret the effect of segmentation on the total measured spine motion. Also it analyzed the relative motion at three types of the spine models in drop landing. A secondary goal was to determine the intrinsic algorithmic errors of spine motion and the usefulness of such an approach as a tool to assess spinal motions. College students in the soccer team were selected the ten males with no history of spine symptoms or injuries. Each subject was given a fifteen minute adaptation period of drop landing on the 30cm height box. Inter-segmental spine motion were collected Vicon Motion Capture System (250 Hz) and synchronized with GRF data (1000 Hz). The result shows that Model III has a more increased range of motion (ROM) than Model I and Model II. And the Lagrange energy has significant difference of at E3 and E4 (p<.05). This study can be concluded that there are differences in the three models of algorithm during the phase of load absorption. Especially, Model III shows proper spine motion for the inter-segmental joint motion with the interaction effects using the seven segments. Model III shows more proper observed values about dynamic equilibrium than Model I & Model II. The findings have shown that the dynamic stability strategy of Model III toward multi-directional spinal motion supports for better function of the inter-segmental motor-control than the Model I and Model II.

• PNF and Movement
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• 제19권2호
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• pp.279-285
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• 2021

Purpose: This study aimed to develop new digital navicular drop test (ND-NDT) equipment and to determine its validity and reliability. Methods: A total of 24 healthy male and female adults, who fully understood the purpose of the study and gave consent to participate in the study, were selected as participants. The NDT and ND-NDT were conducted in the dominant foot of the participants in a random order. For the NDT, the position of the navicular bone was marked with a pen first; then, the height of the navicular bone from the ground was measured in both sitting and standing positions. For the ND-NDT, after the sticker-type reflection markers were attached to the position of the navicular bone, the height of the navicular bone from the ground was measured in both sitting and standing positions. To assess the validity of the diagnostic tests, the same examiner measured the height of the medial longitudinal arch (MLA) three times in both the sitting and standing positions. To assess the inter-rater reliability of the ND-NDT, three examiners, in a random order, attached the sticker-type reflection markers to the position of the navicular bone and then measured the height of the MLA in both positions. Results: In the sitting position, the Pearson correlation coefficient (r) between the two diagnostic tests was very high (r = 0.97) and statistically significant. In the standing position, the Pearson correlation coefficient (r) between the two tests was 0.95, which was also statistically significant. The ICC_2,1 values in the sitting and standing positions were 0.93 and 0.95, respectively, indicating significantly high inter-rater reliability. Conclusion: The ND-NDT equipment showed very high diagnostic validity, as well as excellent inter-rater reliability, indicating the clinical usefulness of the equipment as a diagnostic system for confirming pes planus.

• 패션비즈니스
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• 제17권3호
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• pp.74-84
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• 2013

The purpose of this research is to provide useable data for application in American and Korean apparel company. This data was developed by analyzing information of Korean and American body sizes obtained from "Size USA Project" and "Size Korea Project". The Subjects were 6,306 American females and 1,988 Korean females over 18 years old. 30 measurements and 14 computed values were chosen that were considered critical in making garments. And descriptive analysis, percentile analysis and t-test were used as statistical methods for analyzing measurements and computed value between the two countries. The results were as follows. It was determined that American women were larger and bigger than Korean women in all measurements and computed values, except for Shoulder Slope. Based on BMI values, we determined that American women had a distinct tendency towards being overweight. Through the comparison of drop values (i.e. the difference between Hip and Bust Girths or Hip and Waist Girths), ratio values (i.e. waist height divided by height) and Body Mass Index (BMI) between the two countries, we determined that American women's figures were shapelier than Korean women's. American women had higher hip heights and longer leg lengths for their height compared to Korean woman. Furthermore, the back shapes of Korean women were flatter than American women and BMI values indicated American women were relatively more overweight than Korean women.

• 대한기계학회논문집
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• 제9권4호
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• pp.463-470
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• 1985

본 논문에서는 가열관을 이용한 실험과 고온표면위에 놓인 물방울의 증발실험 을 통하여 재수착온도에 미치는 영향인자들을 분석하였으며, 이러한 분석결과를 토대 로 재수착온도상관식을 제시하였다.

• 한국세라믹학회지
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• 제20권3호
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• pp.199-204
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• 1983

An attempt was made to study wetting behavior of various low temperature molten frist on ceramic substrates including high alumina silicon carbide and porous fired clay plates by Sessile-drop method. The cosine values of contact angles between substrates and molten frist were linear as a function of temperature unless chemical reactions between substrate and molten frit occured. Addition of BaO to frit composition indicated that cosine of values of contact angles were gradually increased with increasing temperature but in the frist contained $Li_2O$ consine values were abruptly increased with increasing temperature after reached a certain temperature. The contact angle increased with increasing roughness of the substrate surface in case of alumina substrate plate.

• 한국도로학회논문집
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• 제12권4호
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• pp.39-46
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• 2010

2007년부터 아이오와 주 교통국에서는 고속도로와 국도에서 FWD 장비를 이용하여 네트워크 레벨에 필요한 조사를 실시하였고 처짐 자료와 포장 구조분석 결과를 데이터베이스로 구축하는 작업을 시작하였다. 축적된 데이터베이스에 정보는 포장에 구조적 문제점을 발견하고 포장에 잔류 공용수명을 예측하여 포장에 유지보수 시점을 결정하는데 사용한다. 현재 아이오와 주 교통국에서 사용하고 있는 FWD 네트워크 레벨 조사 프로토콜은 포장 표면에 3번에 하중을 각각 재하하여 8개에 지오폰으로부터 측정한 처짐량을 이용, 역 계산을 통해 포장구조 해석을 수행하고 있으며 조사지점 수는 조사하는 도로의 구간 길이에 따라 결정하고 있다. 그러나, 현재 사용하고 있은 FWD 네트워크 레벨 조사 프로토콜은 1년 동안 아이오와 주 전체 도로 네트워크에 약 20%만을 조사할 수 있는 것으로 나타났다. 따라서, 해마다 아이오와 주 도로 네트워크에 20% 이상을 조사하기 위해서는 현재 사용하고 있는 FWD 네트워크 레벨 조사 프로토콜을 간소화해야 할 필요가 있다. 본 연구에 목적은 현재 사용하고 있는 FWD 네트워크 레벨 조사 프로토콜에서 FWD 측정 데이터에 영향을 미치지 않는 범위내에서 최소 하중 재하 수와 조사지점 수를 결정하기 위한 것이다. 83개에 합성포장 구간을 대상으로 측정한 FWD 네트워크 레벨 조사에서는 FWD 네트워크 레벨 조사 프로토콜에서 하중 재하 수와 조사지점 수를 줄여도 포장 구조해석 결과에는 크게 영향을 미치지 않는 것으로 나타났다. 간소화된 FWD 네트워크 레벨 조사 프로토콜은 FWD 측정 결과에 영향을 미치지 않으면서 측정 조사율을 높일 수 있을 뿐만 아니라 교통 통제로 인한 간접비용도 절감시킬 수 있을 것으로 기대하고 있다.

• 에너지공학
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• 제15권4호
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• pp.243-249
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• 2006

본 실험적 연구는 슬릿휜-관열교환기의 냉매측 압력강하에 대하여 수행하였다. 응축기의 설계조건에서 미세휜관내 냉매 R22와 R134a의 압력강하에 대한 실험데이터와 앞서 제안한 상관관계식과 상호 비교하였다. 실험은 냉매 R22와 Rl34a의 응축기 입구온도 $60^{\circ}C$, 질량유속 $150{\sim}250\;kg/m^{2}s$ 범위에서 수행하였다. 공기의 유입조건은 건구온도 $35^{\circ}C$, 상대습도 40%이며, 공기유속의 범위는 $0.68{\sim}1.43\;m/s$이다. 실험결과 응축기의 과냉도 $5^{\circ}C$ 조건에서 R134a의 압력강하는 R22보다 $22{\sim}22.6%$ 높게 나타났으며, 냉매의 질량유속 $200{\sim}250\;kg/m^{2}s$의 범위에서 실험으로부터 측정한 R22와 Rl34a의 압력강하는 예측결과와 ${\pm}20%$내에 일치하였다.