• Title/Summary/Keyword: On Resistance

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A Study on the Propulsion Performance of KCS in Still Water and Regular Wave

  • Lee, Sang-Min;Jeong, Uh-Cheul;Kim, Dae-Hae
    • Journal of Navigation and Port Research
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    • v.37 no.1
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    • pp.63-69
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    • 2013
  • Since most merchant vessels are mainly influenced by the added resistance in an actual sea, they could be navigated more efficiently if this added resistance could be precisely predicted and then effectively reduced. In this paper, we have computed the effective horsepower based on the resistance performance in still water and then calculated the added resistance in regular wave in order to estimate a ship's propulsion performance on a voyage. Firstly, we have performed experiments using a model of KCS in a circulating water channel to estimate the flow characteristics around a container ship and the ship's resistance in still water. Then we have calculated the motion response function in regular wave as well as the values for the increase in resistance, and evaluated the ship's motion performance in waves according to the calculated response function. It was found that the resistance in waves increased because the ship's motion response value became larger as the ship's speed increased in the case of head sea. The effect of the added resistance could be reduced by maneuvering the ship to the encounter angle of $120^{\circ}$ in areas of long wavelengths and to head sea in areas of short wavelengths.

A Comparison of Standard Methods for Evaluating the Water Resistance of Shell Fabrics

  • Kwon, Myoung-Sook;Nam, Youn-Ja
    • The International Journal of Costume Culture
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    • v.4 no.3
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    • pp.241-248
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    • 2001
  • Re water resistance of shell fabrics intended for we in outdoor apparel was measured using three different standard test methods, ASTM D 751, hydrostatic resistance, procedure A(Mullen test -- with and without a fabric support) and Procedure B (Hydrostatic head test). A database of information on their water resistance performance was created. The data collected with different methods were correlated and the advantages and disadvantages of each method were compared. The Mullen test with a support appears to give higher and more favorable water resistance values on shell fabrics preventing fabric rupture during the test. The hydrostatic head test gave lower hydrostatic pressure values than those measured on the two Mullen tests. The Mullen test is recommended for testing the water resistance of fabrics that high a relatively high water resistance because the Mullen tester applies a wide range of pressure. The hydrostatic head test is recommended for testing the fabrics that have relatively low water resistance. The area of the fabric sample that is in contact with the water is smaller in the Mullen test, so higher pressure levels can be reached and more samples should probably be tested to get a representative value for each fabric types. Furthermore, the hydrostatic head test was deemed more repeatable than the Mullen tests in his study.

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Study on Memristive Characteristics in Electronic Devices Based on Vanadium Dioxide Thin Films Using 966nm Laser Pulses (966nm 레이저 펄스를 이용한 바나듐 이산화물 박막 기반 전자 소자에서의 멤리스터 특성에 관한 연구)

  • Kim, Jihoon;Lee, Yong Wook
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.11
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    • pp.59-65
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    • 2015
  • By harnessing the thermal hysteresis behavior of vanadium dioxide($VO_2$), we demonstrated multi-resistance states in a two-terminal electronic device based on a $VO_2$ thin film by using a 966nm infrared laser diode as an excitation light source for resistance modulation. Before stimulating the device using 966nm laser pulses, the thermal hysteresis behavior of the device resistance was measured by using a temperature chamber. After that, the $VO_2$ device was thermally biased at ${\sim}71.6^{\circ}C$ so that its temperature fell into the thermal hysteresis region of the device resistance. Six multi-states of the device resistance could be obtained in the fabricated $VO_2$ device by five successive laser pulses with equal 10ms duration and increasing power. Each resistance states were maintained while the temperature bias was applied. And, the resistance fluctuation level was within 2.2% of the stabilized resistance and decreased down to less than 0.9% of the stabilized resistance 5s after the illumination.

A strudyon the improvement of the oxidation resistance for high temperature materials by coating process (코팅에 의한 고온재료의 내산화성 향상을 위한 연구)

  • 강석철;민경안;안연상;김길무
    • Journal of Surface Science and Engineering
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    • v.30 no.2
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    • pp.93-103
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    • 1997
  • High temperature materials used in the elevated temperature and corrosive atmosphere must have the good oxidation resistance and preserve their own mechanical properties simultaneously. For the oxidation resistance, it is very important to form a protective oxide scale such as $Al_2O_3$ or $Cr_2O_3$ on the substrate. However, the additions of protective oxide forming elements such as Cr and Al in the alloy to enhance its oxidation resistance are limited due to the deleterious effects on their mechanical properties. PECVD(P1asma Enhanced Chemical Vapor Deposition) coating processes were employed to improve the oxidation resistance at high temperature. Cr and/or A1 were coated on the substrates of Ni and Inconel 600 at various temperatures of 400, 500, $600^{\circ}C$ and at different conditions of specimen surfaces. Then, coated specimens were exposed to isothermal and cyclic oxidation conditions in air at 1000 and $1100^{\circ}C$. In order to enhance the adhesion between the substrate and coated layer, heat treatments of the coated specimens were conducted in a vacuum. At isothermal oxidation experiments, Al-coated Ni specimen showed better oxidation resistance than pure Ni. At cyclic oxidation experiments at $1000^{\circ}C$. Cr and Al-coated specimen showed better oxidation resistance. Cr-coated Inconel 600 had also showed better oxidation resistance due to Cr in the substrate. By PECVD coating process, oxidation resistance could be improved, but it was not improved as expected due to the weakness of the adhesion between the substrate and the coated layer.

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Factors for the Intra-organizational Diffusion of Big Data Systems (조직 내 빅데이터 시스템 확산에 영향을 주는 요인에 대한 연구)

  • Park, Seungkwan;Kim, Cheong
    • Journal of Information Technology Services
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    • v.18 no.2
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    • pp.97-121
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    • 2019
  • In this paper, factors affecting intra-organizational diffusion of Big Data systems from the perspective of the Big Data system vendors have been analyzed. In particular, the theory of resistance against innovation that exists in some form before the adoption or rejection of innovation has been focused on. In order to do that, the resistance has been divided into three categories : postponement, rejection and opposition. The variables affecting each type are also divided into four independent variables : perceived risk, innovation characteristics, user attributes, and organizational attributes. As a result of the survey, it was confirmed that the influences of each variable are different according to the type of resistance. As the strength of the resistance was increased, the influence of the trialability was increased as well. As the strength of the resistance was decreased, the satisfaction with the existing system became more influential on the resistance. The time risk and the satisfaction with the existing system were found to affect all types of resistance. From the vendor's point of view, strategic implications are presented in terms of marketing or system development for diffusion, depending on the degree of resistance of the adopter.

A Study on Factors Affecting Innovation Resistance and Intention of Use of Social TV Non-Users: Focused on Innovation Diffusion Theory and Innovation Resistance Model (소셜TV 비이용자의 혁신저항과 이용의도에 관한 연구: 혁신확산 이론과 혁신저항모델을 중심으로)

  • Lee, Byung-Hye
    • Journal of Internet Computing and Services
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    • v.18 no.6
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    • pp.101-112
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    • 2017
  • The purpose of this study was to examine the factors affecting innovation resistance and intention of use of social TV non-users focused on innovation diffusion theory and innovation resistance model. The results were as follows: First, compatibility among perceived innovation characteristics by social TV non-users influenced negatively on innovation resistance, and complexity among perceived innovation characteristics by social TV non-users influenced positively on innovation resistance. Second, perceived risk by social TV non-users influenced positively on innovation resistance. Third, compatibility among perceived innovation characteristics by social TV non-users influenced positively on social TV intention to use. And complexity among perceived innovation characteristics by social TV non-users influenced negatively on social TV intention to use. Fourth, perceived risk by social TV non-users influenced not significantly on social TV intention to use. Fifth, innovation resistance by social TV non-users influenced negatively on social TV intention to use.

Analysis of LRFD Resistance Factor for Shallow Foundation on Weathered Soil Ground (풍화토지반 얕은기초에 대한 LRFD 저항계수 분석)

  • Kim, Donggun;Kim, Huntae;Suh, Jeeweon;Yoo, Namjae
    • Journal of the Korean GEO-environmental Society
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    • v.16 no.6
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    • pp.5-11
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    • 2015
  • Recently the necessity of developing the Load and Resistance Factor Design (LRFD) for shallow foundation has been raised to implement to the domestic design codes related to geotechnical engineering since the limit state design is requested as international technical standard for the foundation of structures. In this study, applicability of LRFD for shallow foundation on weathered soils was investigated and resistance factor for this case was proposed. The quantitative analyses on the uncertainty and resistance bias for shallow foundation on weathered soil ground were performed by collecting the statistical data about domestic case studies for design and construction of shallow foundation. Reliability analyses for shallow foundation were first performed using FDA (First-order Design value Approach) method. Resistance factors were calibrated using the load factors obtained from the specifications of shallow foundations on weathered soil ground. The influence of the load factors developed in this study on the resistance factors were discussed by comparing with the resistance factor obtained from using AASHTO load factors.

A Study on the Preliminary Design of Hull Form considering Viscuous Resistance (점성저항을 고려한 선형의 초기설계에 관한 연구)

  • 이경도
    • Journal of Ocean Engineering and Technology
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    • v.14 no.2
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    • pp.112-116
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    • 2000
  • To determine a preliminary hull form with a minimum viscous resistance this study considers the systematic variations of full form and calculations of the viscous resistance for varied hull forms. A preliminary hull form can be determined from a parametric study of viscous resistance.

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Fitness is Recovered with the Decline of Dimethachlon Resistance in Laboratory-induced Mutants of Sclerotinia sclerotiorum after Long-term Cold Storage

  • Li, Jin-Li;Wu, Feng-Ci;Zhu, Fu-Xing
    • The Plant Pathology Journal
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    • v.31 no.3
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    • pp.305-309
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    • 2015
  • After four years of cold storage, dimethachlon resistance of two laboratory-induced resistant Sclerotinia sclerotiorum isolates SCG7 and LA50 declined by 99.5% and 98.9%, respectively, and cross resistance to iprodione and procymidone also declined dramatically. Along with the decline of fungicide resistance, osmotic sensitivity to sodium chloride and glucose decreased tremendously; mycelial growth rate, sclerotia number and weight per potato dextrose agar (PDA) plate increased on average by 118.6%, 85. 5% and 64.5%, respectively; and virulence to detached leaves of oilseed rape increased by 72.7% on average. Significant negative correlations were detected between dimethachlon resistance levels and mycelial growth rate on PDA (r = -0.980, P = 0.021), and between resistance levels and lesion diameters on detached leaves of oilseed rape plants (r = -0.997, P = 0.002). These results have profound implications for assessing the potential risk for resistance development to dicarboximide fungicides in S. sclerotiorum.

Numerical Assessment of Reinforcing Details in Beam-Column Joints on Blast Resistance

  • Lim, Kwang-Mo;Shin, Hyun-Oh;Kim, Dong-Joo;Yoon, Young-Soo;Lee, Joo-Ha
    • International Journal of Concrete Structures and Materials
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    • v.10 no.sup3
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    • pp.87-96
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    • 2016
  • This numerical study investigated the effects of different reinforcing details in beam-column joints on the blast resistance of the joints. Due to increasing manmade and/or natural high rate accidents such as impacts and blasts, the resistance of critical civil and military infrastructure or buildings should be sufficiently obtained under those high rate catastrophic loads. The beam-column joint in buildings is one of critical parts influencing on the resistance of those buildings under extreme events such as earthquakes, impacts and blasts. Thus, the details of reinforcements in the joints should be well designed for enhancing the resistance of the joints under the events. Parameters numerically investigated in this study include diagonal, flexural, and shear reinforcing steel bars. The failure mechanism of the joints could be controlled by the level of tensile stress of reinforcing steel bars. Among various reinforcing details in the joints, diagonal reinforcement in the joints was found to be most effective for enhancing the resistance under blast loads. In addition, shear reinforcements also produced favourable effects on the blast resistance of beam-column joints.