• Title/Summary/Keyword: shrinkage property

Search Result 229, Processing Time 0.033 seconds

A Similarity Solution for the Directional Casting of Peritectic Alloys in the Presence of Shrinkage-Induced Flow (체적수축유동이 있는 포정합금의 방향성주조에 대한 상사해)

  • Yu, Ho-Seon;Jeong, Jae-Dong;Lee, Jun-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.25 no.4
    • /
    • pp.485-495
    • /
    • 2001
  • This paper presents a similarity solution for the directional casting of binary peritectic alloys in the presence of shrinkage-induced flow. The present model retains essential ingredients of alloy solidification, such as temperature-solute coupling, macrosegregation, solid-liquid property differences, and finite back diffusion in the primary phase. An algorithm for simultaneously determining the peritectic and liquidus positions is newly developed, which proves to be more efficient and stable than the existing scheme. Sample calculations are performed for both hypo- and hyper-peritectic compositions. The results show that the present analysis is capable of properly resolving the solidification characteristics of peritectic alloys so that it can be used for validating numerical models as a test solution.

Study on the Material Another Contraction Properties for Prevention that would Float Floor Polished Tiles (바닥 폴리싱 타일 들뜸하자 방지를 위한 각 재료별 수축특성에 관한 연구)

  • Lee, Ji-Hwan;Park, Hee-Gon;Park, Gi-Hong
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2016.05a
    • /
    • pp.175-176
    • /
    • 2016
  • In this study, research is in order to prevent the defects that occur when the polished tiles construction. For material to be used when the polishing tile construction, trying to evaluate the shrinkage characteristics when the environmental conditions change. Depending on the material used for the shrinkage characteristics evaluation results, the difference between the change values of the length of the drying shrinkage becomes large. Therefore, there is a need for the construction method with consideration of the characteristics of the materials used.

  • PDF

A Study on the Time-dependent Characteristics of Prestressed Concrete Box-Girder Bridge (프리스트레스트 콘크리트 박스거더 교량이 시간의존적 특성에 관한 연구)

  • 윤영수;이만섭;최한태
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1998.10b
    • /
    • pp.674-679
    • /
    • 1998
  • In designing the prestressed concrete box-bridge, the dead load, prestressing force, creep and shrinkage of concrete are the main factors which influence the camber and deflection of segmental concrete structure under construction. Among these factors the creep and shrinkage are the functions of the time-dependent property which, therefore, must be considered with time. The prediction model for estimating creep and shrinkage of concrete has been suggested by ACI, CEB/FIP, JSCE and KSCE design code and EMM, AEMM, RCM, IDM and SSM has been suggested for analytical method in consideration of the time-dependent characteristics. In this study, the creep test was carried out for four curing ages of concrete which were applied to the prestressed concrete structure at a construction site, and the results of test were compared to the values of creep prediction by the design code. Also the creep test of step-wise incremental stresses were performed and were compared to analytical methods.

  • PDF

A Study on Thermal Conductivity Properties of Ground Heat Exchangers for GSHP systems (지열냉난방시스템 수직형 지중열교환기 그라우트의 열적 특성에 관한 연구)

  • Baek, Sung-Kwon;Jeon, Joong-Kyu;An, Hyung-Jun
    • Proceedings of the SAREK Conference
    • /
    • 2007.11a
    • /
    • pp.429-433
    • /
    • 2007
  • Cement mortar and concrete can be used as grouts but problems regarding shrinkage and the discord of coefficients of thermal expansion between grouts and HDPE pipes has to be solved. Thermal conductivities of wet condition two times larger than those of dry condition, except for pure cement mortar. The addition of sand into the cement grouts greatly increases the thermal conductivity. The addition of bentonite into the cement grouts reduces thermal conductivity thus reducing the density. Bentonite grouting must be used only below the groundwater table since bentonite grouts possesses high shrinkage property in dry condition. The addition of sand prevents the shrinkage of bentonite grouts. Bentonite manufactured in Korea can be used since they possess similar thermal conductivities with imported products. The addition of sand into the bentonite grouts greatly increases the thermal conductivity.

  • PDF

Material Properties of Grout Using Alumina Cement and Anhydrite (알루미나 시멘트와 무수석고를 이용한 그라우트의 재료적 특성)

  • Hong, Ki-Nam;Jung, Jin-Yeong;Han, Sang-Hoon
    • Journal of the Korean Society of Safety
    • /
    • v.26 no.5
    • /
    • pp.59-64
    • /
    • 2011
  • This paper presents the research results performed to develope the shrinkage-free grout with high early strength. Alumina cement and anhydrite were utilized as the expensive tool to gain the shrinkage-free grout. The compressive strength, length change, and ettringite formation of the grout were investigated with compressive test, length change test, and X-ray diffraction. The more anhydrite was added into the grout, the larger the early expansion of the grout. In addition, the more anhydrite formated the more ettringite. From this study, It was conformed that the grout mixture with shrinkage-free property and high early strength is the mixture with the ratio of alumina cement and anhydrite of 40:60 by weight.

Development of New Surface Design Technique for Natural Dyeing of Silk Fabric by Salt-Shrinkage Finishing (염축가공에 의한 견직물 천연염색의 새로운 표면 디자인 구현기법 개발)

  • Kim, Chaeyeon;Yoo, Dong Il;Shin, Younsook
    • Textile Coloration and Finishing
    • /
    • v.28 no.3
    • /
    • pp.189-194
    • /
    • 2016
  • The objectives of this research were to study the effect of salt-shrinkage finishing of silk on shrinkage degree and dyeing property of cochineal, and to investigate the efficacy of obtained results for imparting surface design effect on silk fabric. Ultimately it was aimed to suggest a technical process for developing natural dyed silk products with diverse design. Premordanted silk fabric was treated with $Ca(NO_3)_2$ solution(gravity: 1.45) at $90^{\circ}C$ for 1 min, washed, dried for further evaluation. The shrinkage of salt-treated fabric was calculated. The effects of salt treatment on the dye uptake of cochineal and colorfastness were investigated. The degrees of shrinkage were 10% and 3% for warp and weft, respectively. The salt treatment resulted in improving dye uptake of cochineal slightly. In addition, it improved colorfastness to washing and light. On the basis of the results, a technical process composed of premordanting, salt treatment and natural dyeing was suggested and using the process, two examples of textile design were presented. It can be concluded to impart various three dimensional surface design effect on silk fabric by applying salt-shrinkage finishing with combination of natural dyeing and mordanting.

The Mechanical Propertis of Wool-like Fabrics Using Composite Textured Yarn (복합가공사를 이용한 Wool-like 직물의 역학적성질)

  • Park, Myung-Soo;Yoon, Jong-Ho
    • Fashion & Textile Research Journal
    • /
    • v.5 no.4
    • /
    • pp.408-412
    • /
    • 2003
  • The micro structure of POY was modified and a wool-like touch yarn of composite fibers with different shrinkage was made. With this yarn 12 different fabrics with wool like touch were prepared. The characteristic physical property changes of the fabrics examined are as follows: 1. In all cases, the initial high shrinkage stages were observed in hot water treatment and the 3D images of complex multilayer of typical doubling fibers with different shrinkage were also observed in hot air treatment of 170C. 2. The tensile strength changes of satin and plain fabrics with the change of twist count showed similar behavior. However, WT's were slightly higher and RT's was lower in twill and satin fabrics than those in plain fabric. 3. Since a slight decrease of B's of twill fabric found with increasing twist count under given experimental condition, it could be influenced on the anti-drape stiffness was decreased and flexibility was increased. 4. A significant decrease of G values was observed in the twist count 800-1000 T.P.M However, in the twist count higher than 1000 T.P.M G values observed were kept nearly constant. 5. MIU of plain and twill fabrics showed a drastic decrease at the twist count higher than 1000 T.P.M.

Process-Structure-Property Relationship and its Impact on Microelectronics Device Reliability and Failure Mechanism

  • Tung, Chih-Hang
    • JSTS:Journal of Semiconductor Technology and Science
    • /
    • v.3 no.3
    • /
    • pp.107-113
    • /
    • 2003
  • Microelectronics device performance and its reliability are directly related to and controlled by its constituent materials and their microstructure. Specific processes used to form and shape the materials microstructure need to be controlled in order to achieve the ultimate device performance. Examples of front-end and back-end ULSI processes, packaging process, and novel optical storage materials are given to illustrate such process-structure-property-reliability relationship. As more novel materials are introduced to meet the new requirements for device shrinkage, such under-standing is indispensable for future generation process development and reliability assessment.

Classification & Property Analysis of Building Interior Materials for Preventing Infectious Disease Spread (전염병 확산방지를 위한 건축내장재 분류 및 특성 분석)

  • Han, Yoon-Jung;Kim, Su-Yeon;Kim, Byoungil
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2017.05a
    • /
    • pp.252-253
    • /
    • 2017
  • The appearance & spread of new kind of virus might cause national economic shrinkage and reduction of foreign tourist. Finally, severe damage of national economy happens. This research wants that after property analysis for generally applied building interior materials, specifically eco-environmental materials including functional materials are reviewed, classified and their special properties in building were investigated.

  • PDF

Effect of Processing Parameters on the Densification-Behaviors by Low Shrinkage in Clay Materials (점토질소지의 공정제어에 따른 저수축 치밀화효과)

  • 임희진;최성철;이응상;이진성
    • Journal of the Korean Ceramic Society
    • /
    • v.33 no.7
    • /
    • pp.725-734
    • /
    • 1996
  • Shrinkage behaviors associated with forming drying and firing processes could be a driving force for the densification in materials. Low shrinkage-densification behaviors in clay materials have been shown to be highly dependent upon the processing parameters including particle size effect and kinetic behaviors caused by phases transformation characteristics. Chamottes pre-treated at 90$0^{\circ}C$ and 120$0^{\circ}C$ had dominent influence upon shrinkage control of materials during heat-treatment. But Coarse chamotte particles heat-treated at 120$0^{\circ}C$ did not contri-bute to any densification behaviors in clay materials while these added coarse particles could enhance near-net-shape control. Microstructure / property relationships in clay materials have been thought to be directly influenced by optimized characteristics between low shrinkage and densification behaviors.

  • PDF