• Title/Summary/Keyword: Technical Investigation

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A reliable approach for determining concrete strength in structures by using cores

  • Durmus, Aysegul;Ozturk, Hasan Tahsin;Durmus, Ahmet
    • Computers and Concrete
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    • v.11 no.5
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    • pp.463-473
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    • 2013
  • As known, concrete classes are described as strength of standard specimens produced and kept in ideal conditions, not including reinforcement and not subjected to any load effect before. Under the circumstances, transforming core strengths to the standard specimen strength is necessary and considering all parameters, affected on the core strength, is inevitable. In fact, effects of the reinforcement and the load history on concrete strength are generally neglected when these mentioned transforms are performing. The main purpose of this paper is investigating the effects of the reinforcement and the load history on the core strength. This investigation is experimentally performed on cores drilled from specimens having different keeping conditions, reinforced, unreinforced, subjected to bending and central pressure in various proportions of failure load during specified periods. Obtained results show that the importance of these effects cannot be neglected.

An experimental investigation of interceptors for a high speed hull

  • Avci, Ahmet Gultekin;Barlas, Baris
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.11 no.1
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    • pp.256-273
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    • 2019
  • Nowadays interceptors have been widely used in a vast range of high-speed crafts. In this study, the results of interceptor adeptness experiments made in Istanbul Technical University's Towing Tank are unveiled. The model was tested through three transverse locations of interceptors with six different deployment depths. For three locations, the interceptor was positioned transverse on the aft; close to chine, in the middle and close to the keel. The fourth interceptor was a full length of 13.00% LWL. The results show a significant drag reduction in benefits of 1.50%-11.30% for Fn 0.58-1.19 and the trim reduction was observed in between 1.60 and $4.70^{\circ}$. Besides, one of the most significant conclusions indicates that the effect of the interceptor decreases from keel to chine for the same blade deployment heights so the blades should be controlled separately at least in three parts from keel to chine area, if operable.

A Study on Recall Systems of Motor Vehicle by Statistical Analysis of Defects Investigation (자동차 제작결함조사 통계 분석을 통한 리콜제도 연구)

  • Song, Ji-hyun;Kwon, Hae-boung;Lee, Kwang-bum;Kim, Hee-june
    • Journal of Auto-vehicle Safety Association
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    • v.7 no.4
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    • pp.20-25
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    • 2015
  • The basic point of a vehicle recall is to remove vehicle defects as soon as possible and thus prevent possible road traffic accidents caused by the defects beforehand. Therefore, the core of vehicle recall under the self-certification system consists of a timely response and fast remedy of defects. The present study aimed to deduce a plan for improvement of the system necessary for the fast remedy of defects through a phased analysis of defect investigation procedure based on defect investigation statistical data. There will be a need to make the TSB(Technical Service Bulletin) or service campaign data submission of a manufacturer compulsory for the collection of broad defect information in the stage of information analysis and to impose a higher penalty when the manufacturer violates the data submission in the investigation stage. In addition, it is considered that an active service campaign should be induced and a punishment for late recall will be needed for consumer protection.

Site Characterization for a Low-level Radioactive Waste Repository (원전수거물 처분장 후보부지 특성평가 방안)

  • 김천수;배대석;박천수
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2003.11a
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    • pp.276-282
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    • 2003
  • The geoscientific study on geological disposal for radioactive wastes has established the stepwise site characterization program, methods and investigation technology. However the intrinsic properties of geological material such as heterogeneity and scale dependent properties make difficulty on satisfactory understanding of geological conditions. To avoid unnecessary time delay and unexpected extra-cost for site investigation, the accurate and complete site investigation program should be established in a stepwise manner and the QC programs for investigation methods and procedures. Moreover, the technical requirements and preferences for a repository should be distinguished and be assessed at the end of each investigation step.

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Development of analysis technique of landslide hazards in natural slopes (자연사면 산사태재해 해석기법 개발)

  • Kim, Kyeong-Su;Song, Young-Suk;Cho, Yong-Chan;Chae, Byung-Gon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.1092-1099
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    • 2009
  • Landslide researches are divided to a method of interrelationship for various factors, method of predicting landslide possibility, and method of estimating landslide risk which are occurring landslides in the natural slope. Most of landslides occurred in natural slope are caused by a heavy rainfall in summer season. Weathered soil layer located in upper side of rock mass was occurred. As well as, they are announced to have an influence to geometry, geology, soil characteristics, and precipitation in the natural slope. In order to investigate and interpret the variety of landslides from field investigation to risk analysis, landslide analysis process due to geotechnical and geological opinions are systematically demanded. In this research, the study area is located in Macheon area, Gyeongsangnam-do and performed the landslide investigation. From the results of landslide investigation and analysis, optimized standard model based on natural landslide is proposed to high technical method of landslide investigation and interpretation.

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An Investigation of Pine Wilt Damage by Using Ground Remote Sensing Technique (지상형 원격탐사기술을 이용한 소나무 재선충 피해조사)

  • Kim, Eung-Nam;Kim, Dae-Young
    • Journal of the Korean association of regional geographers
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    • v.14 no.1
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    • pp.84-92
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    • 2008
  • The first pine wilt damage in Korea, which called AIDS of pine, was found out at Mt. Geumjeong of Pusan province in 1988. The damage area spread 53's city, Gun, Gu throughout the Gyeongsangnamdo in December 2005 since then find out. The best treatment for these damaged forests is well known as fumigation method after early detection. But early detection by an observer is very difficult because of the damaged forest areas are spread over huge range. Also the access of observer is difficult in condition of Korea topographical characteristic. In this study, an attempt was done to investigation about early detection of pine wilt damage using near infrared CCD camera.

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KINETICS OF POLYELECTROLYTE ADSORPTION ON CELLULOSIC FIBRES

  • Lars Wagberg;Sjolund, Anna-Karin
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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    • 1999.11b
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    • pp.34-42
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    • 1999
  • The present investigation has focused up on the study of the adsorption of three different molecular mass fractions of a polyDiMethylDiAllylAmmoniumChloride (DMDAAC) (8750(LM\ulcorner), 48000(MM\ulcorner) and 1200000(HM\ulcorner)) on bleached chemical fibres. Both kinetics of adsorption and equilibrium adsorption measurements have been conducted and each adsorption has been measured by polyelectrolyte titration. The results show that the LM\ulcorner polymer can reach all of the charges in the fibre wall whereas the MM\ulcorner and HM\ulcorner can only reach the external surfaces of the fibres. It is also shown that the kinetics of adsorption of the LMw polymer is not at all affected by the presence of a saturated layer of HMw polymer on the surface of the fibres. Finally, the results from the investigation show that it is possible to have full coverage of the external surface of the fibres by a high molecular mass polymer and a full coverage of the internal surface of the fibres with a low molecular mass polymer. This is true if the high molecular masspolymer is added first followed by addition of the low molecular masspolymer.

Comprehensive experimental investigation on mechanical behavior for types of reinforced concrete Haunched beam

  • Albegmprli, Hasan M.;Gulsan, M. Eren;Cevik, Abdulkadir
    • Advances in concrete construction
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    • v.7 no.1
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    • pp.39-50
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    • 2019
  • This study presents a comprehensive experimental investigation on mostly encountered types of Reinforced Concrete Haunched Beams (RCHBs) where three modes of RCHBs investigated; the diversity of studied beams makes it a pioneer in this topic. The experimental study consists of twenty RCHBs and four prismatic beams. Effects of important parameters including beam type, the inclination angle, flexure and compressive reinforcement, shear reinforcement on mechanical behavior and failure mode of each mode of RCHBs were examined in detail. Furthermore crack propagation at certain load levels were inspected and visualized for each RCHB mode. The results confirm that RCHBs have different behavior in shear as compared to the prismatic beams. At the same time, different mechanical behavior was observed between the modes of RCHBs. Therefore, RCHBs were classified into three modes according to the inclination shape and mode of failure (Modes A, B and C). However, it was observed that there is no significant difference between RCHBs and prismatic beams regarding flexural behavior. Moreover, a new and unified formula was proposed to predict the critical effective depth of all modes of RCHBs that is very useful to predict the critical section for failure.