• 제목/요약/키워드: Internal curing

검색결과 138건 처리시간 0.024초

Undrained shear strength and microstructural characterization of treated soft soil with recycled materials

  • Al-Bared, Mohammed A.M.;Harahap, Indra S.H.;Marto, Aminaton;Abad, Seyed Vahid Alavi Nezhad Khalil;Ali, Montasir O.A.
    • Geomechanics and Engineering
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    • 제18권4호
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    • pp.427-437
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    • 2019
  • Waste materials are being produced in huge quantities globally, and the usual practice is to dump them into legal or illegal landfills. Recycled tiles (RT) are being used in soil stabilisation which is considered as sustainable solution to reduce the amount of waste and solve the geotechnical problems. Although the stabilisation of soil using RT improved the soil properties, it could not achieve the standard values required for construction. Thus, this study uses 20% RT together with low cement content (2%) to stabilise soft soil. Series of consolidated undrained triaxial compression tests were conducted on untreated and RT-cement treated samples. Each test was performed at 7, 14, and 28 days curing period and 50, 100, and 200 kPa confining pressures. The results revealed an improvement in the undrained shear strength parameters (cohesion and internal frication angle) of treated specimens compared to the untreated ones. The cohesion and friction angle of the treated samples were increased with the increase in curing time and confining pressure. The peak deviator stress of treated samples increases with the increment of either the effective confining pressures or the curing period. Microstructural and chemical tests were performed on both untreated and RT-cement treated samples, which included field emission scanning electron microscopic (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and energy dispersive X-ray spectrometer (EDX). The results indicated the formation of cementation compounds such as calcium aluminium hydrate (C-A-H) within the treated samples. Consequently, the newly formed compounds were responsible for the improvement observed in the results of the triaxial tests. This research promotes the utilisation of RT to reduce the amount of cement used in soil stabilisation for cleaner planet and sustainable environment.

C.V.A.환자(患者)의 심장판막질환(心臟瓣膜疾患)에 대한 증례보고(症例報考) (The case report of C.V.A. patient with M.V.H.D)

  • 강민주;정지천;이원철
    • 대한한방내과학회지
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    • 제14권1호
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    • pp.43-54
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    • 1993
  • Observing after enforcing the medication and the acupuncture theraphy on the CVA patient sick with the cerebral embolus by organic pathology of the heart and whose desease was from heat symptoms caused by exessive pathogenic factors of which caused from affection due to exogeneous factors, we obtained the results as follows; 1. Serious condition could be relieved by removing acute symptoms according to the principle of the 'In emergency causes treat the acute symptoms first, when these being relieved treat it's fundament cause'. 2. The lesion could be disable for which the traditional medication theraphy through the differentiation of symptoms-complexes had removed the symptoms caused by organic pathology of heart. 3. The acupuncture stimulation through the differentiation of symptoms seemed to influence electric conduction system. Through this case, If we objectify the diagnosis and the medical treatment, the part of the curing diseases can progress more effectively.

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방제활용을 위한 행인(杏仁)의 포제 및 독성의 문헌적 고찰 (The Study of Literature Review on Poisoning and the Pragmatic Significance of the Processing Method of Armeniacae Amarum Semen to use in oriental medical prescription)

  • 김세란;이진원;임소연;김종대
    • 대한한의학방제학회지
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    • 제19권2호
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    • pp.151-160
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    • 2011
  • Objectives : The purpose of this study was to investigate Armeniacae Amarum Semen of poison and the Pragmatic significance of the processing method. Methods : We researched several books dealing with Armeniacae Amarum Semen of poison and the Pragmatic significance of the processing method. Results & Conclusions : Armeniacae Amarum Semen is sweet, bitter, warm and harmful in nature. It is known as moistening the lung to arrest cough, moistening the colon, to move the bowels and promoting digestion and curing dog bites. Armeniacae Amarum Semen has toxicity, decreasing toxicity of Armeniacae Amarum Semen is boiling, peeling or roasting. If Armeniacae Amarum Semen has two seeds in one apricot or has six-floral leaf, do not used for medicinal purposes.

육미지황탕이 흰쥐의 뇌손상 회복에 미치는 영향 (Effects of Yukmijihwang-tang to Recover the Brain Damage of Mice)

  • 김방울;김경선;전홍열;강화정;김정상;홍석;김용진
    • 대한한방내과학회지
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    • 제23권2호
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    • pp.191-201
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    • 2002
  • Objectives : This study was designed to investigate the effects of Yukmijihwang-tang on contusion of the mice induced with medicine. Methods : I observed the effects of light and electron microscopes. and examined hematological changes and VEGF-immunohistochemistry. Results : Hematology: Leukocytes were increased significantly in a control group of mice compared with the experimental group. Light microscope : A few neurons were condensed in the 7-day experimental group, but condensed remarkedly in the 3-day control group. Most glial cells were observed in the 3-day experimental group. Edema and dilatation of vessels occurred significantly in the 3-day control group, and these results occurred weakly in the 7-day experimental group. VEGF-immunohistochemistry : VEGF-immunohistochemical reactivity for the glial cells was the highest in the 3-day experimental group, and immunoreactivity for the vessels and neurons highly increased in the 7-day experimental group. Electron microscope : In the 3-day control group, protoplasmic astrocytes concerned with angiogenesis contained weakly developed rough endoplasmic reticulum. and a few of glial filaments were observed. In the 7-day experimental group, the bundles of glial filaments were found in the cytoplasmic process of astrocytes. Conclusion : medication using Yukmijihwang-tang of mice contused by medical stress is highly effective in inflamatory response, curing cell damage and angiogenesis.

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SOLUTION OF THE SUPER BESSEL WAVE EQUATION WITH INTEGRAL PARAMETER m

  • Lee, Nae-Ja;Liu, Chang-Keng
    • 대한수학회보
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    • 제20권2호
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    • pp.99-103
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    • 1983
  • Internal heat generation is one of the insidious conditions affecting the quality of an industrial product after it is cast, coated, molded, forged or laminated. Frequently, the product is pressed into service before the exothermic chemical reactions in the generic material has been completed. The heat liberated from this continuing chemical reaction or the residual deformation from the rheological activities in the materials must be adequately removed or prevented, or the product may be discolored, warped, weakened or even "ignited" spontaneously. Numerous instances of premature structural failures, product-recalls, and/or system-malfunctions have been recorded in recent history. The Coulee Dam was poured with pre-chilled concrete just to negate this freakish encore. It is well-known that concrete (a non-isotropic conducting medium), for instance, takes 28 days to develop its full strength. During this period of curing it is conceivable that the processes of internal heat generation, heat conduction and heat dissipation take place simultaneously inside the medium.he medium.

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허혈성(虛血性) 심근(心筋)에 보심단(補心丹)이 미치는 영향(影響) (The Effect of Boshimdan(補心丹:$\breve{b}ux\bar{i}nd\bar{a}n$) on Ischemic Heart Disease)

  • 강명석;고창남;조기호;김영석;배형섭;이경섭
    • 대한한방내과학회지
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    • 제16권2호
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    • pp.61-73
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    • 1995
  • In this study, the effects of Boshimdan, which is used in oriental medicine for the treatment of palpitation, chest discomfort, impatience, insomnia, forgetfulness ete., were tested as a part of series of experimental verification of prescriptions treatments for preventing and curing ischemic heart. The results were as follows: 1. Boshimdan did not effectively work on heart rate of the perfused rat heart. 2. Boshimdan did not effectively work on heart pressure of the perfused rat heart. 3. Boshimdan did not effectively work on flow rate of the perfused rat heart. 4. Boshimdan was not effective in activation of GOT. 5. Boshimdan was not effective in activation of GPT. 6. Boshimdan was not effective in activation of LDH. 7. Boshimdan was not effective in activation of CPK.

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초기재령 콘크리트의 역학적 특성 및 온·습도 거동 특성 분석 (Mechanical Behavior and Characteristics of Internal Temperature and Relative Humidity of Concrete at Early Age)

  • 박철우;이봉학;홍성기
    • 한국구조물진단유지관리공학회 논문집
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    • 제15권6호
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    • pp.184-194
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    • 2011
  • 이 연구에서는 콘크리트 초기재령시의 역학적 특성을 분석하고 수화반응 및 발열반응으로 인한 콘크리트 내부에서 발생하는 온도 및 상대습도의 변화에 대한 분석을 실시하고자 하였다. 세 가지의 다른 단위시멘트량을 실험변수로 하였으며, 타설 직후부터 콘크리트 내부의 온도 및 상대습도의 변화 계측하기 위하여 새로운 계측시스템을 개발하였다. 단위시멘트량에 압축, 인장 및 휨강도의 변화는 크지 않았으며, 재령 7일 이후에는 증가가 많지 않았다. 각 측정부위별 최고 온도는 타설 후 약 11시간 정도 경과시에 발생되었으며 이후 점차 온도가 낮아지다가 양생 1일 경과 후 거푸집 탈형 이후부터 온도가 하강하기 시작했다. 각 측정부위별, 온도감소 분석 결과, 콘크리트 구조물의 위치 및 노출조건에 따라 온도의 변화가 굉장히 다른 것으로 분석되었으며, 초기재령에서 콘크리트 내부의 상대습도의 변화는 수화반응에 영향을 미치는 단위시멘트량 보다는 외부에 노출된 상태가 더 큰 영향을 미칠 수 있는 것으로 분석되었다.

고강도콘크리트 내화성능을 확보한 건식화 PFB 공법 개발에 관한 연구 (A Study on the Development of a Dry PFB Method with High Fire Resistance)

  • 김우재;정상진
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2008년도 추계 학술논문 발표대회
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    • pp.49-52
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    • 2008
  • The present study was to develop a dry PFB method similar to the existing gypsum board construction method in order to apply the existing wet PFB method that uses fire-resistant adhesive. It was found that the existing wet method can produce concrete compressive strength of 80MPa and fire resistance of 3 hours with 30mm PF boards. The goal of development in this study was fire resistance of 3 hours through dry construction of 15mm fire-resistant boards. 1. Improved PF board was prepared by adding inorganic fiber to existing board and using aggregate with grain size of 3mm or less. Molding was done at temperature higher than that for existing PF board molding. While wet curing is used for existing PF boards, this study used dry curing in order to enhance heat insulation performance. 2. According to the results of fire resistance test, when the dry PF method was applied, the temperature of the main reinforcing bar was 116℃ in 15mm, 103.8℃ in 20mm, and 94℃ in 25mm, and these results satisfied the current standards for fire resistance control presented by the Ministry of Land, Transport and Maritime Affairs. When a 3-hour fire resistance test was performed and the external properties of the specimen were examined, the outermost gypsum board hardly remained and internal PF board maintained its form without thermal strain.

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광조형을 이용한 다색 기능성 시작품의 색상특성에 관한 연구 (A study on color characteristics of Multi-color functional Rapid Prototypes Using laser stereolithography)

  • 조진구;정해도;손재혁;임용관
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2000년도 춘계학술대회 논문집
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    • pp.824-828
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    • 2000
  • As production cycle has become more and more shorter, the demand of rapid prototyping technology has increased largely. There are many methods for rapid prototyping technology, such as SLA. SLS, FDM. INK JET, LOM and so on. Of all methods, SLA has been most widely used for fabricating precision parts. But products manufactured by this method have limitation of single color and single material. So the principal purpose of this study is to overcome the limit of single color product. If the internal structure of manufactured product is visible with multi-color characteristic, it is possible to check easily the designed model with reality. In order to give multi-color characteristic to the product, photocurable resin mixed with pigment is used in this study. First, transparency of photocurable resin without pigment is evaluated, and then color characteristic and curing characteristic of the mixture is evaluated changing mixing ratio. Through the basic experiments, it becomes possible to fabricate multi-color 3D prototype without assembly.

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시멘트종류를 변화시킨 프리캐스트 고강도 콘크리트의 실험적 연구 - 수화열 온도특성을 중심으로 - (An Experimental Study of Precast concrete Alters Cement Types of High-Strength Concrete)

  • 박흥이;김성진;백민수;이승훈;박병근;정상진
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2009년도 춘계 학술논문 발표대회 학계
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    • pp.119-122
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    • 2009
  • As architectures have recently become high-risers and mega-structured, stable high strength products have been ensured. Accordingly, use of precast concrete accouplement has been increased in order to facilitate air compression and rationalize construction. Since not only external heating but a1so internal temperature rise caused by the accumulation of cement hydration heat in manufacturing process, precast concrete members with large cross-section used for high-rise mega-structure's columns and beams may exhibit different temperature history compared to the precast concrete members for wall and sub-floor with relatively small cross-sections. Therefore, this study aims to elucidate the characteristics of temperature history of mass concrete members cast with high-strength concrete fur precast concrete application. In this study, large cross-sectional precast concrete mock-up, unit cement quantity, and temperature histories in manufacturing precast concrete member under different curing condition were inclusively investigated.

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