• 제목/요약/키워드: Viscoelasticity

검색결과 290건 처리시간 0.023초

An oil-tolerant and salt-resistant aqueous foam system for heavy oil transportation

  • Sun, Jie;Jing, Jiaqiang;Brauner, Neima;Han, Li;Ullmann, Amos
    • Journal of Industrial and Engineering Chemistry
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    • 제68권
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    • pp.99-108
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    • 2018

  • An oil-tolerant and salt-resistant aqueous foam system was screened out as a possible lubricant to enable cold heavy oil transportation. The microstructures and viscoelasticity and effects of heavy oil, salt and temperature on the foam stability were investigated and new rheological and drainage models were established. The results indicate the foam with multilayered shells belongs to a special microcellular foam. The viscoelasticity could be neglected due to its low relaxation time. The drainage process can be divided into three stages. The foam with quality of 67.9% maintains great stability at high oil and salt concentrations and appropriate elevated temperature.

  • https://doi.org/10.1016/j.jiec.2018.07.033 인용 KSCI

Mechanistic Analysis of Pavement Damage and Performance Prediction Based on Finite Element Modeling with Viscoelasticity and Fracture of Mixtures

  • Rahmani, Mohammad;Kim, Yong-Rak;Park, Yong Boo;Jung, Jong Suk
    • 토지주택연구
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    • 제11권2호
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    • pp.95-104
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    • 2020

  • This study aims to explore a purely mechanistic pavement analysis approach where viscoelasticity and fracture of asphalt mixtures are considered to accurately predict deformation and damage behavior of flexible pavements. To do so, the viscoelastic and fracture properties of designated pavement materials are obtained through experiments and a fully mechanistic damage analysis is carried out using a finite element method (FEM). While modeling crack development can be done in various ways, this study uses the cohesive zone approach, which is a well-known fracture mechanics approach to efficiently model crack initiation and propagation. Different pavement configurations and traffic loads are considered based on three main functional classes of roads suggested by FHWA i.e., arterial, collector and local. For each road type, three different material combinations for asphalt concrete (AC) and base layers are considered to study damage behavior of pavement. A concept of the approach is presented and a case study where three different material combinations for AC and base layers are considered is exemplified to investigate progressive damage behavior of pavements when mixture properties and layer configurations were altered. Overall, it can be concluded that mechanistic pavement modeling attempted in this study could differentiate the performance of pavement sections due to varying design inputs. The promising results, although limited yet to be considered a fully practical method, infer that a few mixture tests can be integrated with the finite element modeling of the mixture tests and subsequent structural modeling of pavements to better design mixtures and pavements in a purely mechanistic manner.

  • https://doi.org/10.5804/LHIJ.2020.11.2.95 인용 PDF KSCI

열처리 공정에 따른 생선단백질의 물성 연구 (Rheological Studies of the Fish Protein upon the Thermal Processing)

  • 강병선;김병용;이재권
    • 한국식품과학회지
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    • 제26권2호
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    • pp.103-109
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    • 1994

  • 응력완화 현상을 측정하여 생선단백질 겔의 선형적 점탄성과 열처리 공정에 따른 물성의 변화를 수식적 모델로 분석하였다. 생선단백질 겔은 정변형도 $0.105{\sim}0.693$, 압축속도 $50{\sim}250\;mm/min$의 범위에서 선형적 점탄성을 나타내었으며, generalized Maxwell 모형에 의해 분석한 결과, 압축변형도과 압축속도가 증가함에 따라 가열에 의해 형성된 내부조직 중 탄성 성분의 증가와 점성성분의 감소현상을 보였다. $4^{\circ}C$와 $40^{\circ}C$에서 전처리하여 $90^{\circ}C$에서 제조한 겔은 전처리 없이 $90^{\circ}C$에서 직접 열처리한 겔보다 탄성율(E) 및 평형탄성율$(E_e)$이 높았으나, 점성성분$({\eta})$은 적용된 모델에 따라서 그 값의 차이가 나타났다. 따라서 식품의 물성을 측정하는데 있어서 두 수학적 모델의 접근방법 및 정확도에 대하여 설명하였다.

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