• Title/Summary/Keyword: Viscoelasticity

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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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    • v.68
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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
    • Land and Housing Review
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    • v.11 no.2
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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

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

  • Kang, Byung-Sun;Kim, Byung-Yong;Lee, Jae-Kwun
    • Korean Journal of Food Science and Technology
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    • v.26 no.2
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    • pp.103-109
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    • 1994

  • Changes in the rheological properties and the linear viscoelasticity of fish protein gel upon the thermal processing were studied by using mathematical models with stress-relaxation data. The linear viscoelasticity of surimi gel was observed in the range of the true strain $0.105{\sim}0.693$ and cross-head speed $50{\sim}250\;mm/min$ applied in this study. The results of the generalized Maxwell analysis showed that the magnitudes of elastic elements $(E,\;E_e)$ were increased, but the viscous element $({\eta}) $was decreased, as the cross-head speeds and strain levels were increased. Compared to the protein gel heated directly at $90^{\circ}C$ without preheating, the protein gel pretreated at $4^{\circ}C$ and $40^{\circ}C$ showed the higher elastic modulus, but showed different trends in the viscous component, depending on the rheological model applied. Thus, the approaching methods and curve fitting of two mathematical models of stress-relaxation to describe the viscoelastic properties of fish protein gel were discussed.

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