The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Gheorghe Gutt - One of the best experts on this subject based on the ideXlab platform.
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a viscoelastic model for honeys using the time Temperature Superposition principle ttsp
Food and Bioprocess Technology, 2013Co-Authors: Mircea Oroian, Sonia Amariei, Isabel Escriche, Gheorghe GuttAbstract:The viscoelastic parameters storage modulus (G′) and loss modulus (G″) were measured at different Temperatures (5 °C, 10 °C, 15 °C, 20 °C, 25 °C, 30 °C, and 40 °C) using oscillatory thermal analysis in order to obtain a viscoelastic model for honey. The model (a 4th grade polynomial equation) ascertains the applicability of the time–Temperature Superposition principle (TTSP) to the dynamic viscoelastic properties. This model, with a regression coefficient higher than 0.99, is suitable for all honeys irrespective their botanical origin (monofloral, polyfloral, or honeydew). The activation energy (relaxation“ΔHa” and retardation “ΔHb”), and the relaxation modulus fit the model proposed. The relaxation modulus has a 4th grade polynomial equation evolution at all Temperatures. The moisture content influences all the rheological parameters.
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A Viscoelastic Model for Honeys Using the Time–Temperature Superposition Principle (TTSP)
Food and Bioprocess Technology, 2013Co-Authors: Mircea Oroian, Sonia Amariei, Isabel Escriche, Gheorghe GuttAbstract:The viscoelastic parameters storage modulus ( G ′) and loss modulus ( G ″) were measured at different Temperatures (5 °C, 10 °C, 15 °C, 20 °C, 25 °C, 30 °C, and 40 °C) using oscillatory thermal analysis in order to obtain a viscoelastic model for honey. The model (a 4th grade polynomial equation) ascertains the applicability of the time–Temperature Superposition principle (TTSP) to the dynamic viscoelastic properties. This model, with a regression coefficient higher than 0.99, is suitable for all honeys irrespective their botanical origin (monofloral, polyfloral, or honeydew). The activation energy (relaxation“Δ H _a” and retardation “Δ H _b”), and the relaxation modulus fit the model proposed. The relaxation modulus has a 4th grade polynomial equation evolution at all Temperatures. The moisture content influences all the rheological parameters.
R M Guedes - One of the best experts on this subject based on the ideXlab platform.
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a viscoelastic model for a biomedical ultra high molecular weight polyethylene using the time Temperature Superposition principle
Polymer Testing, 2011Co-Authors: R M GuedesAbstract:Abstract The objective of this study was to obtain a mathematical model of the viscoelastic functions of a medical grade ultra high molecular weight polyethylene (UHMWPE). This model ascertained the applicability of the time–Temperature Superposition principle (TTSP) to the dynamic viscoelastic properties obtained from dynamic mechanical thermal analysis (DMTA). It was verified that both horizontal and vertical shifts were necessary to superimpose the dynamic modulus/frequency curves. A new methodology is proposed and assessed to determine the horizontal and vertical shift factors for the time–Temperature Superposition. The present approach is based on a viscoelastic model, a fractional Maxwell model which, associated with the proposed methodology, leads to an easy and effective way to calculate these shift factors. The main advantage relies in the fact that the factors are obtained via a viscoelastic model, not empirically, which provides physical significance to both shift factors.
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A viscoelastic model for a biomedical ultra-high molecular weight polyethylene using the time–Temperature Superposition principle
Polymer Testing, 2011Co-Authors: R M GuedesAbstract:Abstract The objective of this study was to obtain a mathematical model of the viscoelastic functions of a medical grade ultra high molecular weight polyethylene (UHMWPE). This model ascertained the applicability of the time–Temperature Superposition principle (TTSP) to the dynamic viscoelastic properties obtained from dynamic mechanical thermal analysis (DMTA). It was verified that both horizontal and vertical shifts were necessary to superimpose the dynamic modulus/frequency curves. A new methodology is proposed and assessed to determine the horizontal and vertical shift factors for the time–Temperature Superposition. The present approach is based on a viscoelastic model, a fractional Maxwell model which, associated with the proposed methodology, leads to an easy and effective way to calculate these shift factors. The main advantage relies in the fact that the factors are obtained via a viscoelastic model, not empirically, which provides physical significance to both shift factors.
Clive R. Siviour - One of the best experts on this subject based on the ideXlab platform.
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Rate dependence of poly(vinyl chloride), the effects of plasticizer and time–Temperature Superposition
Proceedings of The Royal Society A: Mathematical Physical and Engineering Sciences, 2014Co-Authors: Michael J. Kendall, Clive R. SiviourAbstract:Four different poly(vinyl chloride) (PVC) materials varying in plasticizer content were studied in a combined experimental and analytical investigation including uniaxial compression tests at strain rates ranging from 10−3 to 104 s−1 at room Temperature, and Temperatures ranging from −115 to 100°C at a rate of 10−2 s−1. Additional tests using a dynamic mechanical and thermal analyser were conducted on each PVC material to give a more detailed analysis of Temperature and rate dependence. Adjusting the plasticizer content allows the Temperature at which transitions, specifically the α-transition, or ‘glass transition’, and β-transition, occur to be moved in order to better examine the interplay of Temperature and strain rate dependence. This program of research is then extended to time–Temperature Superposition where a novel application and interpretation of an established Superposition method is presented.
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rate dependence of poly vinyl chloride the effects of plasticizer and time Temperature Superposition
Proceedings of The Royal Society A: Mathematical Physical and Engineering Sciences, 2014Co-Authors: Michael J. Kendall, Clive R. SiviourAbstract:Four different poly(vinyl chloride) (PVC) materials varying in plasticizer content were studied in a combined experimental and analytical investigation including uniaxial compression tests at strain rates ranging from 10−3 to 104 s−1 at room Temperature, and Temperatures ranging from −115 to 100°C at a rate of 10−2 s−1. Additional tests using a dynamic mechanical and thermal analyser were conducted on each PVC material to give a more detailed analysis of Temperature and rate dependence. Adjusting the plasticizer content allows the Temperature at which transitions, specifically the α-transition, or ‘glass transition’, and β-transition, occur to be moved in order to better examine the interplay of Temperature and strain rate dependence. This program of research is then extended to time–Temperature Superposition where a novel application and interpretation of an established Superposition method is presented.
N W Tschoegl - One of the best experts on this subject based on the ideXlab platform.
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time Temperature Superposition in thermorheologically complex materials
Journal of Polymer Science Part C: Polymer Symposia, 2007Co-Authors: D G Fesko, N W TschoeglAbstract:Two-phase polymeric materials such as polymer blends, block copolymers, and graft copolymers, are thermorheologically complex. Mechanical response curves obtained on such materials at different Temperatures cannot, in principle, be brought into Superposition by a simple shift along the logarithmic time or frequency axis. The shift factors become functions of time or frequency in addition to Temperature. A general treatment of time-Temperature Superposition in thermorheologically complex materials is developed and a model is proposed from which, for a two-phase material, the amount of shift can be calculated which is necessary to bring a point on a mechanical response curve obtained at a given Temperature and time or frequency into Superposition at another Temperature. The mechanical responses of the constituent homopolymers and their Temperature functions must be known.
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Time‐Temperature Superposition in thermorheologically complex materials
Journal of Polymer Science Part C: Polymer Symposia, 2007Co-Authors: D G Fesko, N W TschoeglAbstract:Two-phase polymeric materials such as polymer blends, block copolymers, and graft copolymers, are thermorheologically complex. Mechanical response curves obtained on such materials at different Temperatures cannot, in principle, be brought into Superposition by a simple shift along the logarithmic time or frequency axis. The shift factors become functions of time or frequency in addition to Temperature. A general treatment of time-Temperature Superposition in thermorheologically complex materials is developed and a model is proposed from which, for a two-phase material, the amount of shift can be calculated which is necessary to bring a point on a mechanical response curve obtained at a given Temperature and time or frequency into Superposition at another Temperature. The mechanical responses of the constituent homopolymers and their Temperature functions must be known.
Noelle Billon - One of the best experts on this subject based on the ideXlab platform.
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large strain time dependent mechanical behaviour of pmmas of different chain architectures application of time Temperature Superposition principle
Polymer, 2018Co-Authors: C E Federico, Jeanluc Bouvard, Christelle Combeaud, Noelle BillonAbstract:Abstract The relevance of equivalent strain rate at reference Temperature derived from time/Temperature Superposition principle is validated as a constitutive parameter at large strain for PMMAs of different chain architecture. Shift factors were obtained from DMTA at infinitesimal strain, then identified according to Williams-Landel-Ferry or Arrhenius equations and finally extended to large deformations. Mechanical behaviour was characterized under cyclic tensile loading. So-called 3D digital image correlation was used to measure local strain. It is demonstrated that for different experimental conditions having same equivalent strain rate, the macroscopic behaviour will be the same. This was validated for elastoplastic, viscoelastic and rubbery behaviours. Such experimental observations indicate that time/Temperature Superposition at low strain can be extended for large deformation for PMMA. Additionally, the study opens a new way of addressing the Temperature and strain rate dependencies in constitutive model by using the equivalent strain rate at reference Temperature as a unique parameter.
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Large strain/time dependent mechanical behaviour of PMMAs of different chain architectures. Application of time-Temperature Superposition principle
Polymer, 2018Co-Authors: C E Federico, Jeanluc Bouvard, Christelle Combeaud, Noelle BillonAbstract:Abstract The relevance of equivalent strain rate at reference Temperature derived from time/Temperature Superposition principle is validated as a constitutive parameter at large strain for PMMAs of different chain architecture. Shift factors were obtained from DMTA at infinitesimal strain, then identified according to Williams-Landel-Ferry or Arrhenius equations and finally extended to large deformations. Mechanical behaviour was characterized under cyclic tensile loading. So-called 3D digital image correlation was used to measure local strain. It is demonstrated that for different experimental conditions having same equivalent strain rate, the macroscopic behaviour will be the same. This was validated for elastoplastic, viscoelastic and rubbery behaviours. Such experimental observations indicate that time/Temperature Superposition at low strain can be extended for large deformation for PMMA. Additionally, the study opens a new way of addressing the Temperature and strain rate dependencies in constitutive model by using the equivalent strain rate at reference Temperature as a unique parameter.
