• Title/Summary/Keyword: push test

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Interfacial shear resistance of angle shear connectors welded to concrete filled U-shaped CFS beam

  • Oh, Hyoung Seok;Shin, Hyeongyeop;Ju, Youngkyu;Kang, Thomas H.K.
    • Steel and Composite Structures
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    • v.43 no.3
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    • pp.311-325
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    • 2022
  • For multi-story structural systems, Korean steel industry has fostered development of a steel-concrete composite beam. Configuration of the composite beam is characterized by steel angle shear connectors welded to a U-shaped cold formed-steel beam. Effects of shear connector orientation and spacing were studied to evaluate current application of the angle shear connector design equation in AC495. For the study, interfacial shear resistance behavior was investigated by conducting 24 push-out tests and attuned using unreinforced push-out specimens. Interfacial shear to horizontal slip response was reported along with corresponding failure patterns. Pure shear connector strength was also evaluated by excluding concrete shear contribution, which was estimated in relation to steel beam-slab interface separation or interfacial crack width.

Nail Withdrawal Resistance and Embedding Strength of Structural Wood Panels with Water Absorption (수분의 흡수에 따른 구조용 목질판넬의 인발 및 함입성능)

  • 오세창
    • Journal of the Korea Furniture Society
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    • v.10 no.2
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    • pp.1-8
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    • 1999
  • The use of structural wood based panels like plywood, OSB in many applications involves the use of nails, and data on the performance of panel-nail connection are needed for design and comparative purpose. This study was carried out to develop basic information on nail performance(withdrawal, embedding, nailhead push through) with water absorption in plywood and OSB. In withdrawal resistance test, initial stiffness of plywood performed better than OSB in 24hr soaked condition. The soaked condition reduced average nail withdrawal resistance value about 46% (12d mail), 53%(8d nail) in OSB, 17%(12d mail), 24%(8d mail) in plywood. The nail embedding strength of plywood also performed better than that of OSB and retention value(wet strength/dry strength) yielded similar in each nail types. The nail head push through capacity of OSB was higher than that of plywood in dry condition, but equal or lower in soaked condition. Therefore, critical consideration about structural panels is required in moist applications. The average values of nail withdrawal, nail embedding strength and nail head push through resistance of tested materials meet the minimum requirement of various specification and standards.

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Understanding Individual's Switching Intentions to Smart Appliances : A Perspective of the Push-Pull-Mooring Framework and Status Quo Bias (스마트 가전의 전환의도에 관한 연구 : 이주이론과 현상유지편향 관점)

  • Kim, Sang-Hyun;Park, Hyun-Sun
    • The Journal of Information Systems
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    • v.27 no.2
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    • pp.221-245
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    • 2018
  • Purpose This study aims to investigate the factors that influence switching intention of Smart Appliances. We focuses on Push-Pull-Mooring theory and status quo bias as factors related to switching behavior. Design/methodology/approach This study developed an model to explain the switching intention of Smart Appliances and conducted structural equation modeling with AMOS22.0. To test the proposed hypotheses, we collected 319 survey responses from smart appliances's users. Findings The results indicated that low usefulness and low ease of use had an effect on the switching intention of smart appliances. The results also indicated that attractiveness of the alternative and social norms had an effect on the switching intention of smart appliances. Lastly, The difference between the relation of push effect and switching intention and the relation of pull effect and switching intention was found to be due to the level of status quo bias. The academic and managerial implications were discussed based on the results of empirical analysis.

A Study on User Switching Intention from Contact Center-oriented to AI Chatbot-Oriented Customer Services (컨택센터 중심에서 인공지능 챗봇 중심 고객 서비스로의 사용자 전환의도에 관한 연구)

  • Ann Seunggyu;Ahn Hyunchul
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.19 no.1
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    • pp.57-76
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    • 2023
  • This study analyzes the factors and effects on the users' intention to switch from contact center-oriented to AI chatbot-oriented customer services by combining Push-Pull-Mooring Model and provides insights for companies considering the adoption of AI chatbots. To test the model, we surveyed users with experience using chatbots at least once across different age groups. Finally, we analyzed 176 cases for the analysis using IBM SPSS Statistics and SmartPLS 4.0. The results of hypotheses testing rejected the hypotheses for variables of inconsistent quality and low availability of push factors and low switching cost of mooring factor while accepting the hypotheses for the tardy response of push factors and all pull factors. Therefore, these findings provide important implications for researchers and practitioners who wish to conduct research or adopt AI chatbots. In conclusion, users do not feel inconvenienced by the contact center-oriented service but also perceive high trust and convenience with AI chatbot-oriented service. However, despite low switching costs, users consider chatbots a complementary tool rather than an alternative. So, companies adopting AI chatbots should consider what features the users expect from AI chatbots and facilitate these features when implementing AI chatbots.

Factors Affecting the Customer Satisfaction of Rural Experience -Applying Unified PPM Model - (농어촌 체험 고객 만족에 영향을 미치는 요인)

  • Choi, Yang-ae;Chung, Byoung-gyu
    • Journal of Venture Innovation
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    • v.2 no.2
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    • pp.79-94
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    • 2019
  • The purpose of this study is to explore the factors affecting rural experience by applying the unified push-pull-mooring model. The theoretical model is an unified PPM model that introduces new variables based on PPM. The pull factor of the newly introduced variables were reconstructed based on the Schmitt's Experience model and ServQual model. The hypothesis is set as follows. The push factor will have a negative effect on experience satisfaction and the pull factor(experience attributes, service quality)will have a positive effect on experience satisfaction. Also, mooring factors will have a negative effect on experience satisfaction. The research model of this study was tested by structural equation model based on 314 effective questionnaire data. Service quality had a positive effect on experience satisfaction. Mooring factors have a negative effect on experience satisfaction. Push factor and experience attributes factor were analyzed to have a no significance effect on experience satisfaction. These results theoretically test that the mooring factors also have an important effect on the experience satisfaction in the rural experience. Based on the Schmitt's Experience model and ServQual model introduced as a pull factor, the proposed unified PPM model proved to be a useful analysis framework. In practice, it was able to provide implications on what factors should be strategically and marketingly focused to activate the 6th industry experience.

Shear Stiffness of Shear connections in Full-Depth Precast Concrete Deck Bridge (프리캐스트 바닥판 교량 전단연결부의 전단강성)

  • Shim, Chang Su;Chung, Chul Hun;Kim, Chul Young;Chang, Sung Pil
    • Journal of Korean Society of Steel Construction
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    • v.10 no.4 s.37
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    • pp.749-758
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    • 1998
  • The evaluation of shear stiffness of shear connection in composite bridges with CIP concrete deck is analysed. Shear stiffness of shear connection in full-depth precast concrete deck bridges is obtained from experiments. 3-dimensional finite element analyses of push-out specimen are carried out to investigate the effects of characteristics of filling material strength in shear connection on shear stiffness and local stress distribution. The load-slip relations obtained from the analyses are compared with those of experiments. The equation of initial shear stiffness of shear connection in precast concrete deck bridge is proposed. Linear analyses are performed to evaluate the effects of the shank diameter of shear connector and the strength of mortar on the characteristics of deterioration and failure load obtained by the failure criterions of each material. The failure loads are estimated and compared with test results.

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Single Well Push-Pull Test를 이용한 TCE 오염 지하수의 In-Situ Bioremediation 타당성조사

  • Kim, Yeong;Istok, Jonnathan;Semprini, Lewis
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2003.04a
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    • pp.188-191
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    • 2003
  • Sing]e-well-push-pull tests were developed for use in assessing the feasibility of in-situ aerobic cometabolism of chlorinated aliphatic hydrocarbons (CAHs). The series includes Transport tests, Biostimulation tests, and Activity tests. Transport tests are conducted to evaluate the mobility of solutes used in subsequent tests. These included bromide or chloride (conservative tracers), propane (growth substrate), ethylene, propylene (CAH surrogates), dissolved oxygen (electron acceptor) and nitrate (a minor nutrient). Tests were conducted at an experimental well field of Oregon State University. At this site, extraction phase breakthrough curves for all solutes were similar, indicating apparent conservative transport of the dissolved gases and nitrate prior to biostimulation. Biostimulation tests were conducted to stimulate propane-utilizing activity of indigenous microorganisms and consisted of sequential injections of site groundwater containing dissolved propane and oxygen. Biostimulation was detected by the increase in rates of propane and oxygen utilization after each injection. Activity tests were conducted to quantify rates of substrate utilization and to confirm that CAH-transforming activity had been stimulated. In particular, the transformation of injected CAH surrogates ethylene and propylene to the cometabolic byproducts ethylene oxide and propylene oxide provided evidence that activity of the monooxygenase enzyme system, responsible for aerobic cometabolic transformations of CAHs had been stimulated. Estimated zero-order transformation rates decreased in the order propane > ethylene > propylene. The series of push-pu3l tests developed and field tested in this study should prove useful for conducting rapid, low-cost feasibility assessments for in situ aerobic cometabolism of CAHs.

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Effect of antioxidants on push-out bond strength of hydrogen peroxide treated glass fiber posts bonded with two types of resin cement

  • Khoroushi, Maryam;Mazaheri, Hamid;Tarighi, Pardis;Samimi, Pouran;Khalighinejad, Navid
    • Restorative Dentistry and Endodontics
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    • v.39 no.4
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    • pp.303-309
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    • 2014
  • Objectives: Hydrogen peroxide ($H_2O_2$) surface treatment of fiber posts has been reported to increase bond strength of fiber posts to resin cements. However, residual oxygen radicals might jeopardize the bonding procedure. This study examined the effect of three antioxidant agents on the bond strength of fiber posts to conventional and self-adhesive resin cements. Materials and Methods: Post spaces were prepared in forty human maxillary second premolars. Posts were divided into five groups of 8 each: G1 (control), no pre-treatment; G2, 10% $H_2O_2$ pre-treatment; G3, G4 and G5. After $H_2O_2$ application, Hesperidin (HES), Sodium Ascorbate (SA) or Rosmarinic acid (RA) was applied on each group respectively. In each group four posts were cemented with Duo-Link conventional resin cement and the others with self-adhesive BisCem cement. Push-out test was performed and data were analyzed using 2-way ANOVA and tukey's post-hoc test (${\alpha}=0.05$). Results: There was a statistically significant interaction between the cement type and post surface treatment on push-out bond strength of fiber posts (p < 0.001, F = 16). Also it was shown that different posts' surface treatments significantly affect the push-out bond strength of fiber posts (p = 0.001). $H_2O_2$ treated posts (G2) and control posts (G1) cemented with Duo-link showed the highest ($15.96{\pm}5.07MPa$) and lowest bond strengths ($6.79{\pm}3.94$) respectively. Conclusions: It was concluded that $H_2O_2$ surface treatment might enhance the bond strength of fiber posts cemented with conventional resin cements. The effect of antioxidants as post's surface treatment agents depends on the characteristics of resin cements used for bonding procedure.

Experimental and numerical studies on the shear connectors in steel-concrete composite beams at fire and post fire exposures

  • Mirza, Olivia;Shil, Sukanta Kumer;Rashed, M.G.;Wilkins, Kathryn
    • Steel and Composite Structures
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    • v.39 no.5
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    • pp.529-542
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    • 2021
  • Shear connectors are required to build composite (concrete and steel) beams. They are placed at the interface of concrete and steel to transfer shear and normal forces between two structural components. Such composite beams are sensitive to provide structural integrity when exposed to fire as they loss strength, stiffness, and ductility at elevated temperature. The present study is designed to investigate the shear resistance and the failure modes of the headed stud shear connectors at fire exposure and post-fire exposure. The study includes ordinary concrete and concrete with carbon nanotubes (CNTs) to build composite (concrete-steel) beams with structural steel. Experimental push tests were conducted on composite beams at ambient and elevated temperatures, such as 200, 400 & 600℃. Moreover, push tests were performed on the composite beams after being exposed to 200, 400 & 600℃. Push test results illustrated the reduction of ultimate shear capacity and stiffness of headed stud shear connectors as the temperature increased. Although similar values of ultimate shear were obtained for the headed stud connectors in both ordinary and CNT concrete, the CNT modified concrete reduced the concrete spalling and cracking compared to ordinary concrete and was observed to be effective at temperatures greater than 400℃. All specimens showed a lower shear resistance at fire exposures compared to the corresponding post-fire exposures. Moreover, numerical simulation by Finite Element (FE) analyses were carried out at ambient temperature and at fire conditions. The FE analysis results show a good agreement with the experimental results. In the experimental studies, failure of all specimens occurred due to shear failure of headed stud, which was later validated by FE analyses using ABAQUS.

Estimation of Shear Strength of RC Shear Connection for the Steel-Concrete Composite Girder (강합성 거더용 철근콘크리트 전단연결체의 전단강도 평가)

  • Shin, Hyun Seop;You, Young Jun;Jeong, Youn Ju;Eom, In Su
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.3A
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    • pp.229-239
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    • 2010
  • For the purpose of improvement of the load carrying capacity and constructibility of the conventional steel-concrete composite girder through a effective appliance of the construction materials and optimization of the girder section, a new type section of composite girder and RC shear connection were proposed. In this study shear strength of the RC shear connection is estimated, and the characteristics of shear load-slip behaviour is analyzed. Push-out tests on shear specimens and FEM analysis with various design parameters are carried out, and results are analyzed. The results of test and FEM analysis showed that shear strength of RC shear connection is underestimated by the design provisions of the current design code. By regression analysis a empirical equation for the estimation of shear strength of RC shear connection is proposed.