• 제목/요약/키워드: New Repair Materials

검색결과 124건 처리시간 0.03초

황산칼슘, 아말감 및 수산화칼슘이 치근분지부 천공부위에 미치는 치유효과에 관한 비교 연구 (AN EVALUATION OF THE EFFECT OF CALCIUM SULFATE, AMALGAM AND CALCIUM HYDROXIDE IN THE REPAIR OF FURCATION PERFORATIONS)

  • 강충규;노병덕;이승종
    • Restorative Dentistry and Endodontics
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    • 제22권1호
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    • pp.93-109
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    • 1997
  • Finding a right repair material for furcation perforation is one of the major issues in clinical endodontics. In this experiment, three materials, calcium sulfate, amalgam, and calcium hydroxide were tested for perforated furcation repair. Sixty premolars and molars of five dogs were used. A #4 round bur was used to create the perforation. All experimental teeth were divided into two repair-time groups. One was immediate-repair group, where the perforation was repaired immediately, the other was delayed-repair group, where the perforation was left open for four weeks and then repaired with the same manner as in the immediate-repiar group. All chamber openings were sealed with amalgam and then radiographed. The animals were sacrificed at eighth week following the repair procedure. Radiographic evaluation for furcal bone destruction was done. Histologic evaluation was ranked as 0,1,2,3 according to the inflammation degrees. New bone formation was also recorded. The following conclusions were drawn within the limits of the experimental results: 1. In immediate-repair group, no significant differences existed between the materials. 2. In delayed-repair group, calcium sulfate showed significantly less furcal bone destruction and lower inflammation degree than amalgam.(p<0.05) 3. Overextruded specimens showed more severe inflammation than unextruded specimens. 4. Most of the specimens showed certain degrees of inflammatory reaction and incomplete hard tissue healing. 5. In delayed-repair group, treated group showed less inflammation than untreated control group.

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모델 변천에 따른 가스터빈 연소기 라이너의 부위별 손상유형 분석 (Analysis of Damage Patterns for Gas Turbine Combustion Liner according to Model Change)

  • 김문영;양성호;박상열;김상훈;박혜숙;원종범
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회B
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    • pp.2862-2867
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    • 2008
  • High-temperature components of gas turbine operated for certain period of time can be reused by being repaired or rejuvenated. In case of the gas turbine combustion liners, the biggest and the most important one in the high-temperature components, come in a repair shop after operated for 8,000 or 12,000 hours according to the model and go through the repair and rejuvenation in order to be reused. A stated combustion liner is the first channel which has the combustion gas reached a nozzle from a fuel nozzle. Materials and coating properties of old and new model combustion liners were investigated. To repair these components after the visual inspection, the coatings of combustion liners were removed and then FPI(Fluorescent Penetrant Inspection), a kind of the NDI(Non-Destructive Inspection), was conducted. Damage patterns and the number of the damaged components were classified and analyzed based on data provided from the visual inspection over a long period of time. Focusing on the difference between old model and new model combustion liners, we analyzed the damage distribution and changes and consequently concluded that new model combustion liner would increase repair rate.

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도자기 수리복원 방법의 변천과정에 관한 고찰 (A Study on the Changes Process Repair and Restoration Method of Ceramic)

  • 양필승;서정호
    • 보존과학회지
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    • 제27권1호
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    • pp.49-59
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    • 2011
  • 손상된 도자기는 고대부터 여러 가지 방법과 재료를 사용하여 수리복원 되었다. 도자기 수리복원의 역사는 전통적인 수리방법을 이용해 실생활에서 활용 가능한 재료들을 사용하던 방식에서 새로운 재료의 도입과 다양한 처리기법의 시도 및 사용된 재료의 분석에 이르는 전문적인 분야로까지 그 영역을 넓히며 발전을 거듭하여 왔다. 우리나라의 도자기 수리복원 방법의 변천과정은 출토유물과 문헌자료, 분석 등을 통해 조사한 결과, 동물이나 식물에서 추출된 접착제, 석회와 같은 복원제 등을 사용하여 수리 복원하던 천연재료 사용 시기(고대~일제 강점기 이전)와, 주사비 등 천연재료와 합성수지가 혼합되어 사용되는 시기(일제 강점기~1970년대), 새로운 처리기법과 재료가 도입되고 보존규범에 입각하여 수리복원이 이루어진 합성수지 사용 시기(80년대 이후)로 구분 할 수 있었다.

도로 및 비탈면 유실 항구적 긴급복구를 위한 골재망 콘크리트 활용기술 개발 (Emergency and Permanent Repair Technology for Damaged Road Bases and Slopes using Gravel-Netting Concrete)

  • 김용재;정해국;김승원;박철우
    • 한국도로학회논문집
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    • 제20권2호
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    • pp.9-17
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    • 2018
  • PURPOSES : The frequency and severity of natural disasters such as torrential rain or typhoons have become increasingly significant worldwide. Events such as summer typhoons and localized torrential downpour can cause severe damages to a residential area and road networks, resulting in serious harm to the daily lives of people, especially in rural areas by isolating residents from road networks. An immediate and emergency repair technology for the collapsed road networks is urgently needed. This study introduces a new technology to repair road bases or slopes. METHODS : The development of new technology for emergency and permanent repair consists of first, packing of cement paste-coated gravel, second, combining appropriate equipment, and third, conducting a field applicability test. In this research, the compressive strength of cement pastecoated gravel, gravel-netting concrete properties, and packing efficiency were determined, and a full scale field mock-up test was carried out. RESULTS : The compressive strength of the cement paste-coated gravel concrete satisfied the required limit for road base of 5 MPa after 7 days. With appropriate netting materials and packing size, gravel-netting concrete was successful up to a slope of 1:1.5. The full scale field mock-up test showed efficiency in the field and penetration resistance performance. CONCLUSIONS : The new technology of emergency and permanent repair for damaged road bases and slopes, introduced in this study, showed satisfactory performance. The technology is expected to be applied in the field when construction procedures and quality specifications are made.

FRP Rod를 이용한 표면매립 및 단면 확대 복합 보수$\cdot$보강 공법 (Repair and Strengthening Method Using Near Surface Mounted FRP Rods and Overlay)

  • 황금식;박찬기;원종필
    • Composites Research
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    • 제18권4호
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    • pp.66-74
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    • 2005
  • This paper reports new repair and strengthening mathod using improved material. This mathod have two type according to covering thickness of reinforcement. One type is near surface mounted FRP rod. Anther type is overay. Fiber Reinforced Plastic (FRP) materials has become very popular in recent years. FRP material used to rehabilitate many types of structures with superior characteristics such as high strength and stiffness and corrosion resistance. This strengthening mathod were used FRP rod which have better bond and shear strangth than current FRP rod. Development of FRP rod due to 3-D winding system. In addition, Ductile hybrid FRP has a certain plastic deformation and an elongation greater than 3% at maximum load is usually required for steel reinforcement in concrete structures. Moerover this mathod can be effective repair of base concrete by sprayed polymer mortar.

RTM을 이용한 노후 지하 매설관의 보수-보강에 관한 연구 (A Study on Repairing Retired Underground Buried Pipes Using RTM)

  • 진우석;권재욱;이대길
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2000년도 추계학술발표대회 논문집
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    • pp.249-252
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    • 2000
  • To overcome problems of excavation technology far repairing or replacing underground buried pipes which are worn out or damaged, various trenchless repair-reinforcement technologies have been invented. But these trenchless technologies also have many problems in the aspect of economy and convenience of operation. In this research, the repair-reinforcement process using RTM (Resin Transfer Molding) which can solve problems of present trenchless technologies was developed. The resin wetting and void removal during RTM process to form large composite structures inside of buried pipes were experimentally investigated. From the experiment, it was found that the new technology had advantage over conventional methods by employing appropriate process parameters and void removal vents.

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Standardization and Method Selection for the Trenchless Repair Technology of Sewer using Cured-in-place Pipe

  • Kim, Taeeung
    • International Journal of Internet, Broadcasting and Communication
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    • 제14권2호
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    • pp.70-78
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    • 2022
  • The trenchless entire repair technology (TERT) have many different names depending on the companies, and they have the same or similar methods as well as materials. In addition, there was quiet difficulty in application of field working and even confuse to classify for new TERT, while application criteria of TERT is not listed systematically. This study proposed standardization and method for TERT affecting by pipe condition, working materials, working method, specification/quantity per unit according to field condition, strange affairs and others. Determination criteria of defective sewer pipe has proposed to effective method which modify a criteria between Ministry of Environment and Seoul Metropolitan City. A Cured-in-place pipe (CIPP) is suitable for TERT, and the design criteria for the entire broken pipe are proposed when the pipe itself deforms more than 10%. A check lists are specimen preparing, hardening site made by clamped mold, numbers, flexural and tensile property, water leak and desquamation test, and have to use material property of minimum CIPP value depend on ISO 11296-4, ISO 11297-4, KS M3550-7 and KS M3550-9.

재활용을 위한 폐아스팔트 혼합재의 역학적 특성 (The Engineering Characteristic of Asphalt Waste for Recycling)

  • 정성윤;이규환;정대석
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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    • pp.932-937
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    • 2008
  • The asphalt waste has been collected more than ten thousands' ton from repairing works on the road and excavation repair works, most of them are disposed on land of reclamation. Only a few percentage of wasted asphalt recycled to new one. Therefore, In this study, usage of wasted asphalt and has been done engineered characteristic test for recycling materials of sub-grade and structure. To know the characteristic of asphalt waste, tamping test, bearing-ratio test, permeability test and direct shear test was done using asphalt-sand mixture. The test results shows that, mixed asphalt materials with sand can be used for materials of subgrade-soil and structure.

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탄소섬유그리드 보강 휨부재의 거동에 대한 실험적 연구 (An Experimental Study on the Behavior of Carbon Fiber Grid Reinforced Flexural Members)

  • 박제용;안동준;정상균;윤순종
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 1999년도 추계학술발표대회 논문집
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    • pp.154-159
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    • 1999
  • In this paper we present tile results of an experimental investigation on the physical and mechanical properties of carbon fiber grid, polymer mortar, and carbon fiber grid reinforced plain concrete flexural members. In order to repairing and reinforcing damaged and/or deteriorated existing concrete structural members, new materials have been developed and utilized in the construction industries. But the physical and mechanical behaviors of the material are not well understood. To use the material effectively various aspects of the material must be throughly investigated analytically as well as experimentally. In this investigation we found the physical and mechanical properties of carbon fiber grid and polymer mortar which are directly utilized in the repair and reinforcement design of damaged or deteriorated concrete structures. In addition, we also investigate the strengthening effect of carbon fiber grid on the plain concrete flexural test specimens. It was found that the material can be used to repair and strengthen the concrete structures effectively.

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On magnetostrictive materials and their use in adaptive structures

  • Dapino, Marcelo J.
    • Structural Engineering and Mechanics
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    • 제17권3_4호
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    • pp.303-329
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    • 2004
  • Magnetostrictive materials are routinely employed as actuator and sensor elements in a wide variety of noise and vibration control problems. In infrastructural applications, other technologies such as hydraulic actuation, piezoelectric materials and more recently, magnetorheological fluids, are being favored for actuation and sensing purposes. These technologies have reached a degree of technical maturity and in some cases, cost effectiveness, which justify their broad use in infrastructural applications. Advanced civil structures present new challenges in the areas of condition monitoring and repair, reliability, and high-authority actuation which motivate the need to explore new methods and materials recently developed in the areas of materials science and transducer design. This paper provides an overview of a class of materials that because of the large force, displacement, and energy conversion effciency that it can provide is being considered in a growing number of quasistatic and dynamic applications. Since magnetostriction involves a bidirectional energy exchange between magnetic and elastic states, magnetostrictive materials provide mechanisms both for actuation and sensing. This paper provides an overview of materials, methods and applications with the goal to inspire novel solutions based on magnetostrictive materials for the design and control of advanced infrastructural systems.