• Title/Summary/Keyword: Design resistance

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A study on towing power of trawlers and a proper scale of trawl gears (트롤선 유효마력과 어구의 적정 규모에 대한 연구)

  • LEE, Chun-Woo;CHOI, Kyu-Suk;JANG, Yong-Suk
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.57 no.1
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    • pp.1-9
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    • 2021
  • Trawl fishing is a fishing method in which a large, motorized trawler tows a bag-shaped net to catch fish living at the bottom or middle layers. For a trawl gear, it is of utmost importance to select the gear size and towing speed suitable for the effective horsepower (EHP) of the trawler in the design stage. In general, the power required to move an object is proportional to the product of the object speed and resistance; therefore, there are various choices for the gear resistance and towing speed given the effective horsepower of the trawler. However, there have been few studies on the gear design of an appropriate scale for the towing speed given the effective horsepower of the trawler. In this study, the resistance and shape of three types of midwater trawl gears were analyzed using SimuTrawl, a computer simulation tool. In addition, the relationship between the propulsion force and speed of the ship was clarified when the size and effective horsepower of the trawler were determined. Finally, we suggested the relationship between the towing speed and the resistance of the gear when the trawler towed the net was investigated, and a specific method of selecting the gear size according to the towing speed.

Estimation of Resistance Bias Factors for the Ultimate Limit State of Aggregate Pier Reinforced Soil (쇄석다짐말뚝으로 개량된 지반의 극한한계상태에 대한 저항편향계수 산정)

  • Bong, Tae-Ho;Kim, Byoung-Il;Kim, Sung-Ryul
    • Journal of the Korean Geotechnical Society
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    • v.35 no.6
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    • pp.17-26
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    • 2019
  • In this study, the statistical characteristics of the resistance bias factors were analyzed using a high-quality field load test database, and the total resistance bias factors were estimated considering the soil uncertainty and construction errors for the application of the limit state design of aggregate pier foundation. The MLR model by Bong and Kim (2017), which has a higher prediction performance than the previous models was used for estimating the resistance bias factors, and its suitability was evaluated. The chi-square goodness of fit test was performed to estimate the probability distribution of the resistance bias factors, and the normal distribution was found to be most suitable. The total variability in the nominal resistance was estimated including the uncertainty of undrained shear strength and construction errors that can occur during the aggregate pier construction. Finally, the probability distribution of the total resistance bias factors is shown to follow a log-normal distribution. The parameters of the probability distribution according to the coefficient of variation of total resistance bias factors were estimated by Monte Carlo simulation, and their regression equations were proposed for simple application.

Pullout Resistance Characteristics of Strip-type Reinforcement based on Extensibility (신장성에 따른 띠형 보강재의 인발저항 특성)

  • Lee, Kwang-Wu;Cho, Sam-Deok;Han, Jung-Geun;Hong, Kikwon
    • Journal of the Korean Geosynthetics Society
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    • v.11 no.4
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    • pp.37-44
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    • 2012
  • This paper describes large scale pullout test results, in order to evaluate extensibility effect of strip-type reinforcement. The same test for ribbed steel strip reinforcement also is conducted to compare the friction resistance reinforcements' evaluation results. The pullout resistance of the ribbed steel strip reinforcement, which has a small cross sectional areas, was better than the friction resistance reinforcements' due to the bearing (passive) resistance. In case of friction resistance reinforcements, the pullout resistance of extensible reinforcement was better than inextensible reinforcement' even though they have a similar cross sectional areas.

The Structural Relationships among Innovation Characteristics, Consumer Characteristics, Innovation Resistance, and Intention to Acceptance of Wearable Device Customers: Based on Innovation Resistance Model and Theory of Perceived Risk (웨어러블 디바이스 소비자의 혁신특성, 소비자특성, 혁신저항, 그리고 수용의도와의 구조적 관계: 혁신저항모형과 인지된 위험이론을 기반으로)

  • Bae, Jae Kwon
    • The Journal of Information Systems
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    • v.25 no.4
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    • pp.87-104
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    • 2016
  • Purpose As the smartphone market arrived at its saturation, from world leading information and communications technologies (ICT) businesses to startups, companies are competing to develop innovative wearable device products and suitable contents. Utility, technology, design, price, and various killer contents development targeting every customer's need should be considered for a success in the wearable device market. Design/methodology/approach Prior studies on innovation technology of ICT field have mainly focused on the innovation diffusion theory, expectation confirmation theory, and technology acceptance model, this study suggested the innovation resistance factors of adopting the smart wearable devices based on the innovation resistance model and theory of perceived risk. The model comprises the following two characteristics factors: 1) innovation characteristics which include perceived relative advantages, perceived compatability, perceived complexity, and perceived risk, 2) consumer characteristics which include attitudes towards innovation and existing products (i.e., mobile devices and analog watches). This study developed an extended innovation resistance model to explain the intention to acceptance of wearable devices consumers and collected 284 online survey responses from the non-consumers of the wearable devices. Findings The findings of this study suggest that perceived relative advantage, perceived compatibility, perceived complexity, perceived risk, attitudes towards innovation and attitudes towards existing analog watches affected the innovation resistance which has negative influence on the intention to adoption of wearable devices.

Combined Effects of Gastrocnemius Stretch and Tibialis Anterior Resistance Exercise in Subjects with Limited Ankle Dorsiflexion

  • Lee, Jihyun;Cynn, Heonseock;Shin, Areum;Kim, Bobeen
    • Physical Therapy Rehabilitation Science
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    • v.10 no.1
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    • pp.10-15
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    • 2021
  • Objective: Limited ankle dorsiflexion is related to ankle injuries. There are various exercises to increase the flexibility of the gastrocnemius for improving the passive range of motion in ankle dorsiflexion. However, to performances in daily activities and athletic sports and higher efficiency of walking and running, both ankle dorsiflexion passive and active range of motion are needed. To investigate the effects of combined gastrocnemius stretching and tibialis anterior resistance exercise on ankle kinematics (passive and active range of motion of ankle dorsiflexion) and tibialis anterior muscle activity in subjects with limited ankle dorsiflexion. Design: Cross-sectional single-group repeated measures design. Methods: Fourteen subjects with limited ankle dorsiflexion were recruited (in the right ankle in 7 and the left ankle in 7). All subjects performed gastrocnemius stretching alone and tibialis anterior resistance exercise after gastrocnemius stretching. The passive and active range of motion of ankle dorsiflexion were measured after interventions immediately. The tibialis anterior activity was measured during active range of motion of ankle dorsiflexion measurement. Results: There was no significant difference of ankle dorsiflexion passive range of motion between gastrocnemius stretching alone and the tibialis anterior resistance exercise after gastrocnemius stretching. The tibialis anterior resistance exercise after gastrocnemius stretching significantly increased active range of motion of ankle dorsiflexion compared to gastrocnemius stretching alone (p<0.05). The tibialis anterior resistance exercise after gastrocnemius stretching significantly increased tibialis anterior activity better than did gastrocnemius stretching alone. Conclusions: Thus, subjects with limited ankle dorsiflexion should be encouraged to perform tibialis anterior resistance exercises.

Effects of surface-roughness and -oxidation of REBCO conductor on turn-to-turn contact resistance

  • Y.S., Chae;H.M., Kim;Y.S., Yoon;T.W., Kim;J.H., Kim;S.H., Lee
    • Progress in Superconductivity and Cryogenics
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    • v.24 no.4
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    • pp.40-45
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    • 2022
  • The electrical/thermal stabilities and magnetic field controllability of a no-insulation (NI) high-temperature superconducting magnet are characterized by contact resistance between turn-to-turn layers, and the contact resistance characteristics are determined by properties of conductor surface and winding tension. In order to accurately predict the electromagnetic characteristics of the NI coil in a design stage, it is necessary to control the contact resistance characteristics within the design target parameters. In this paper, the contact resistance and critical current characteristics of a rare-earth barium copper oxide (REBCO) conductor were measured to analyze the effects of surface treatment conditions (roughness and oxidation level) of the copper stabilizer layer in REBCO conductor. The test samples with different surface roughness and oxidation levels were fabricated and conductor surface analysis was performed using scanning electron microscope, alpha step surface profiler and energy dispersive X-ray spectroscopy. Moreover, the contact resistance and critical current characteristics of the samples were measured using the four-terminal method in a liquid nitrogen impregnated cooling environment. Compared with as-received REBCO conductor sample, the contact resistance values of the REBCO conductors, which were post-treated by the scratch and oxidation of the surface of the copper stabilizer layer, tended to increase, and the critical current values were decreased under certain roughness and oxidation conditions.

The Design of Oxide Module for High Temperature Thermoelectric Power Generation (고온 발전용 산화물 열전모듈의 설계)

  • Park, Jong-Won;Yoon, Sun-Ho;Cha, Jeong-Eui;Choi, Seung-Chul
    • Journal of the Microelectronics and Packaging Society
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    • v.15 no.4
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    • pp.93-100
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    • 2008
  • The one and two pair of oxide modules for high temperature thermoelectric power generation were fabricated with $Ca_{2.7}Bi_{0.3}Co_4O_9$(p-type) and $Ca_{0.96}Bi_{0.04}Mn_{0.96}Nb_{0.04}O_3$(n-type) on $Al_2O_3$ substrate. For the optimizing of the design process, contact resistance was derived from the results of the one pair modules, and then the resistance of two pair modules were calculated to use the derived data. Those values were compared with the measured values for the optimizing of this design process. The resistance of calculated and measured two pairs modules was 0.956 $\Omega$ and 1.110 Q $\Omega$ $T_h$=833 K, respectively, the difference of resistance was about 0.15 $\Omega$. From the result, proposed design process is effective for high temperature thermoelectric oxide modules fabrication.

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A Convergence Study through Flow Analysis due to the Configuration of Automotive Air Breather (자동차 에어 브리더의 형상에 따른 유동해석을 통한 융합연구)

  • Oh, Bum Suk;Cho, Jae-Ung
    • Journal of the Korea Convergence Society
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    • v.9 no.10
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    • pp.265-270
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    • 2018
  • In this study, the flow analysis due to the car body configuration of air breather was carried out. As the resistance force whose flow affects car body has been studied, it is published that the electricity can be decreased. When the inner pressure of air breather is evaluated, there is the study of efficiency in order to raise the flow rate of inner body. At a total of five models, it is shown that the air resistance and pressure happen differently and the air pressure of side flow is changed. This study result was analyzed by using the analysis program of ANSYS, a study model was modelled using the CATIA V5 modelling program. It was investigated that the air flow rate was distributed uniformly as the curved surface of air breather configuration increases. It is thought as the most effective design method to design the air breather by considering the effect on the air resistance and flow. Also, through the design of the vehicle's airbrid configuration, the design of the product can incorporate a aesthetic sense into the design.

Clarification of the Thermal Properties of Intumescent Paint and Suggestion of the Required Fire Protection Thickness for Steel and Composite columns (철골 및 합성기둥 내화성능 확보를 위한 내화페인트 열적 물성치 규명과 소요두께 제안)

  • Kim, Sun-Hee;Ok, Chi Yeol;Choi, Sung-Mo
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.6 no.1
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    • pp.21-29
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    • 2015
  • Other countries(USA, Europe) have performed the fire resistance design of buildings by the alternative performance design methods, which are based on fire engineering theories. However, in Korea, the process on the alternative fire resistance performance design has only suggested without any applications for real steel structures. Therefore, In the case of steel structures stagnant research on refractory measures face difficulties in introducing fire resistance design. In this study, first of all, Intumescent paint was analyze the thermal properties(thermal conductivity, specific heat and density). In Sequence, using the section factor by H-standard section propose of section concrete filled steel tube and hollow. finally presents a reasonable thickness Intumescent paint takes time to target performance of the proposed cross-section steel tube.