• Title/Summary/Keyword: strengthening techniques

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Experimental and numerical study about seismic retrofitting of corrosion-damaged reinforced concrete columns of bridge using combination of FRP wrapping and steel profiles

  • Afshin, Hassan;Shirazi, Mohammad R. Nouri;Abedi, Karim
    • Steel and Composite Structures
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    • v.30 no.3
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    • pp.231-251
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    • 2019
  • In the present study, a numerical and experimental investigation has been carried out on the seismic behavior of RC columns of a bridge which damaged under corrosive environments and retrofitted by various techniques including combined application of CFRP sheets and steel profiles. A novel hybrid retrofitting procedure, including the application of inner steel profiles and outer peripheral CFRP sheets, has been proposed for strengthening purpose. Seven large-scale RC columns of a Girder Bridge have been tested in the laboratory under the influence of simultaneous application of constant axial load and the lateral cyclic displacements. Having verified the finite element modeling, using ABAQUS software, the effects of important parameters such as the corrosion percentage of steel rebars and the number of CFRP layers have been evaluated. Based on the results, retrofitting of RC columns of the bridge with the proposed technique was effective in improving some measures of structural performance such as lateral strength degradation and higher energy absorption capability. However, the displacement ductility was not considerably improved whereas the elastic stiffness of the specimens has been increased.

Institutional Strategy of Palm Oil Independent Smallholders: A Case Study in Indonesia

  • ANWAR, Khairul;TAMPUBOLON, Dahlan;HANDOKO, Tito
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.4
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    • pp.529-538
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    • 2021
  • This article aims to describe the institutional structuring strategy of independent smallholders in accelerating sustainable economic development, by taking the example of the cow-coconut integration system (SISKA) problem in Sialang Palas Village, Riau. The method used identified stakeholders related to SISKA; the stakeholder's goals and interests, farmers' social and institutional bases, and self-help farmer socio-economic networks. First, identification of various factors through strengths, weaknesses, opportunities, and threats (SWOT) analysis techniques. Second, through the Modern Political Economy analysis technique. Third, imparting knowledge and skills to the farmers and village officials through a collective learning process in utilizing natural resource waste and social resources. The results showed that the farmer management strategy in the reform era started by clustering the interests of farmers. The dynamics of structuring group relations between the chairman and members with farmers outside the group are the basis for strengthening the local ideology of independence in the future. This institutional structuring strategy that focuses on access to farm power in the village decision-making process encourages a more integrated work of farmer organizations. The analysis above shows that the independent smallholder institutional engineering through regulation, organization, and resources are determined by the farmer household economic factors and the application of the value of local wisdom.

Development of Collision Safety Control Logic using ADAS information and Machine Learning (머신러닝/ADAS 정보 활용 충돌안전 제어로직 개발)

  • Park, Hyungwook;Song, Soo Sung;Shin, Jang Ho;Han, Kwang Chul;Choi, Se Kyung;Ha, Heonseok;Yoon, Sungroh
    • Journal of Auto-vehicle Safety Association
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    • v.14 no.3
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    • pp.60-64
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    • 2022
  • In the automotive industry, the development of automobiles to meet safety requirements is becoming increasingly complex. This is because quality evaluation agencies in each country are continually strengthening new safety standards for vehicles. Among these various requirements, collision safety must be satisfied by controlling airbags, seat belts, etc., and can be defined as post-crash safety. Apart from this safety system, the Advanced Driver Assistance Systems (ADAS) use advanced detection sensors, GPS, communication, and video equipment to detect the hazard and notify driver before the collision. However, research to improve passenger safety in case of an accident by using the sensor of active safety represented by ADAS in the existing passive safety is limited to the level that utilizes the sudden braking level of the FCA (Forward Collision-avoidance Assist) system. Therefore, this study aims to develop logic that can improve passenger protection in case of an accident by using ADAS information and driving information secured before a collision. The proposed logic was constructed based on LSTM deep learning techniques and trained using crash test data.

Predicting and analysis of interfacial stress distribution in RC beams strengthened with composite sheet using artificial neural network

  • Bensattalah Aissa;Benferhat Rabia;Hassaine Daouadji Tahar
    • Structural Engineering and Mechanics
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    • v.87 no.6
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    • pp.517-527
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    • 2023
  • The severe deterioration of structures has led to extensive research on the development of structural repair techniques using composite materials. Consequently, previous researchers have devised various analytical methods to predict the interface performance of bonded repairs. However, these analytical solutions are highly complex mathematically and necessitate numerous calculations with a large number of iterations to obtain the output parameters. In this paper, an artificial neural network prediction models is used to calculate the interfacial stress distribution in RC beams strengthened with FRP sheet. The R2value for the training data is evaluated as 0.99, and for the testing data, it is 0.92. Closed-form solutions are derived for RC beams strengthened with composite sheets simply supported at both ends and verified through direct comparisons with existing results. A comparative study of peak interfacial shear and normal stresses with the literature gives the usefulness and effectiveness of ANN proposed. A parametrical study is carried out to show the effects of some design variables, e.g., thickness of adhesive layer and FRP sheet.

A study to improve the national technical qualification practical evaluation method of National Competency Standards in the field of organic agriculture

  • Hyun-Ho, Jang;Taek-Keun, Oh;Jwakyung, Sung
    • Korean Journal of Agricultural Science
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    • v.48 no.4
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    • pp.855-863
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    • 2021
  • The purpose of this study is to suggest an improvement plan for the National Technical Qualification Practical Evaluation focusing on National Competency Standards. First, in order to strengthen practical techniques such as field abilities and expertise, practical evaluation methods were applied to the National Competency Standards, referring to a learning module focused on field performance. Second, an expert advisory committee in the field of organic agriculture was utilized to compare, analyze, and match the competency unit and competency unit elements of the National Competency Standards with the national technical qualification examination standards in field of organic agriculture. In addition, in order to identify work in progress in the industrial field, share professional practice skills, and analyze facilities and equipment, we visited an organic agriculture industry site. Through this, a practical evaluation exam was developed. Subsequently, in order to confirm the adequacy of the developed exam, the pilot test assessment was conducted for those majoring in organic agriculture. Finally, as a feasibility study, a survey was conducted. Based on the results, greater technical job competency in the field of organic agriculture will contribute to strengthening knowledge in this field by suggesting an improvement plan for the national technical qualifications practical evaluation method in the field of organic agriculture.

Housing Policy Capacity and Indonesian Response to the COVID-19 Pandemic

  • SURURI, Ahmad
    • Journal of Wellbeing Management and Applied Psychology
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    • v.5 no.4
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    • pp.11-17
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    • 2022
  • Purpose: This study discusses how Indonesia's response to the Corona Virus Disease-19 pandemic based on the perspective of housing policy capacity which consists of resources, organizations, and networks, politics, systems, and finance. Research design, data and methodology: This study used a qualitative method through a literature review. Data collection techniques were carried out by searching various sources and literature related to housing capacity theory and various data on Indonesia's response to the Covid 19 pandemic. Based on a literature review, this study adapted and modified the five components of capacity, namely resource capacity, organizational and network capacity, political capacity, system capacity and financial capacity in Indonesia in responding to the Covid-19 pandemic. Data analysis used analytical themes which consist of understanding the data, generating initial codes, looking for themes, reviewing themes, defining and naming themes, producing of manuscripts. Results: The results show that the weakness of the system capacity greatly affects Indonesia's housing policy capacity in responding to the Covid-19 pandemic and on the other hand the five housing capacities are an integrated process within the housing policy framework in Indonesia, especially to overcome the Covid-19 pandemic. Conclusions: The findings of this study are the importance of building a system capacity that is directly integrated with housing policy and the strengthening of the resources capacity, organizations, and networks, politics, and finance in the context of Indonesia's housing policy, especially in dealing with the Covid-19 pandemic situation.

A study on curing the wounded heart applications development and effect analysis by utilizing narrative therapy techniques (이야기치료 기법을 활용한 마음상처 치유 어플리케이션 개발 및 효과분석)

  • Ha, Tai-Hyun;Baek, Hyeon-gi
    • Journal of Digital Contents Society
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    • v.16 no.2
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    • pp.207-218
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    • 2015
  • This study is to design and implement Smartphone application by applying the principles and processes of narrative therapy for the participants. The application is able for participants to fight out of the difficulty in question centered on the issue, and to be able to find a positive new stories to be evolving the story of their lives as well. Therefore, using the application will help them to live a healthier life out of the problems. As a way of currying the wounded heart of the youth, narrative therapy techniques were applied to Smartphone appliances accustomed to the youth. The youths' wounded minds will not only be easily cured but also can be a important factor in determining the direction of life. In this study, narrative flow was structured into four stages; relationships, externalization, creating new stories and strengthening the new story bsed on Doll & Doll' theory. Based on them, the Smartphone application for curing the wounded heart was designed and developed by utilizing narrative therapy techniques. The application was tested by 30 University students in Jeonbuk province in Korea and the results showed that they were satisfied with the application with relation to improving their heart health.

Development and Application of Literacy Education program using Coaching methods (코칭기법을 활용한 문해교육프로그램 개발 및 적용)

  • Yang, Bog Yi;Kim, Jin Sook
    • The Journal of the Convergence on Culture Technology
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    • v.7 no.3
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    • pp.261-268
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    • 2021
  • After developing literacy education programs using coaching techniques, applying them to literacy learners, in order to see how they have an impact on improving learning achievement, we selected 13 senior literacy learners in U city and chose qualitative research method based on in-depth interviews, observation journals, and learning materials. Literature education programs using coaching techniques are a process-oriented model consisting of four stages of mind-opening, introducing positivity, strengthening learning competence and assistance, confidence and persistence. You can find the results as following. Firstly, communication between teachers and learners was expanded in the first stage, and secondly, self-directed learning ability was strengthened in the second stage by forming a positive mind. Thirdly, the results of utilizing the three-stage balanced literacy teaching method and interaction teaching method resulted in confidence in reading and writing, leading to an increase in self-efficacy. Fourthly, the fourth stage showed the results of improving learning achievement, which overcame the fear of learning with active praise and continuous encouragement and implied hope for higher courses. As a result of the above-mentioned research, I think literacy education programs using coaching techniques can be useful as an educational method for learners in the field of literacy education.

Analytical Evaluation of High Velocity Impact Resistance of Two-way RC Slab Reinforced with Steel Fiber and FRP Sheet (강섬유 및 FRP Sheet로 보강한 2방향 RC 슬래브의 고속 충격저항성능에 대한 해석적 평가)

  • Lee, Jin Young;Shin, Hyen Oh;Min, Kyeng Hwan;Yoon, Young Soo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.3
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    • pp.1-9
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    • 2013
  • This paper presents high-velocity impact analysis of two-way RC slabs, including steel fibers and strengthening with fiber reinforced polymer (FRP) sheets for evaluating impact resistance. The analysis uses the LS-DYNA program, which is advanced in impact analysis. The present analysis was performed similarly to the high-velocity impact tests conducted by VTT, the technical research center of Finland, to verify the analysis results. High-velocity impact loads were applied to $2100{\times}2100{\times}250$ mm size two-way RC slab specimens, using a non-deformable steel projectile of 47.5kg mass and 134.9m/s velocity. In this research, extra impact analysis of material specimens was carried out to verify the material models used to the analysis. The elastic-plastic hydrodynamic model, concrete damage model and orthotropic elastic model were used to simulate the non-linear softening behavior of steel fiber reinforced concrete (SFRC), and material properties of normal concrete and FRP sheets, respectively. It is concluded that the suggested analysis technique has good reliability, and can be effectively applied in evaluating the effectiveness of reinforcing/retrofitting materials and techniques. Also, the Steel fiber and FRP sheet strengthening systems provided outstanding performance under high-velocity impact loads.

Study on the Manufacturing techniques & Conservation of Iron Pot from Cheonmachong Ancient Tomb (천마총 출토 철부(鐵釜)의 제작기법 및 보존처리)

  • Lee, Seung Ryul;Shin, Yong Bi;Jung, Won Seob
    • Journal of Conservation Science
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    • v.30 no.3
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    • pp.263-275
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    • 2014
  • It's shown how to proceed the study on Manufacturing techniques & Conservation to the Iron Pot from Cheonmachong Ancient Tomb(the 155th Tomb in Hwangnam-dong). In order to investigate manufacturing techniques of the Iron Pot, some parts of the relic were gathered. After mounting, polishing and etching on the relic, analyzing the metal microstructure was conducted. Also it's conducted a SEM-EDS analysis on the nonmetallic inclusion. White iron structure was observed in the metallurgical structure inspection, SEM-EDS analysis. It seems to be dried slowly at room temperature after casting, doesn't look as particular heat treatment to improve brittleness. It is estimated that it's as the handle seam side were verified about 3cm inch wide, 1.5 thick in center of body, so 2 separate half-completed products was cast with width-type mould. The manufacturing techniques Using white cast iron structure, width-type mould are observable to the Iron Pot excavated from Sikrichong Ancient Tomb & Hwangnamdaechong grand Ancient Tomb around those were constructed the same time. It's able to recognize that it's almost identical manufacturing techniques at that time. Conservation is generically following those are survey of pretreatment, foreign material removal, stabilization, restoration and color matching in the order. cleaning & drying were added to the process as occasion demands. The strengthening treatment were difficult with artifact's volume, low concentration Paraloid NAD-10 solution was spread two or three times with a brush, surface hardening also came up with 15wt% Paraloid NAD-10 solution after the conservation was complete. There were connection & restoration for the restoration to the damage after modeling forms that it's similar to damaged parts by using the Fiber Reinforced Plastic resins(POLYCOAT FH-245, mold laminated type). Throughout this research, capitalizing on accumulations of measurements about the production technique of Iron Pot in the time of the fifth and 6th centuries is no less important than the Iron artifact's conservation for a better study in the future.