Development and validation of a semi-analytical framework for droplet freezing with heterogeneous nucleation and non-linear interface kinetics

2020 ◽  
pp. 120734
Author(s):  
Saad Akhtar ◽  
Minghan Xu ◽  
Agus P. Sasmito
Keyword(s):  
Heterogeneous Nucleation ◽  
Analytical Framework ◽  
Interface Kinetics ◽  
Non Linear ◽  
Development And Validation

Viscoelastic Behavior of Carbon Nanotube Yarns and Twisted Coils

2018 ◽  
Author(s):  
Pouria Khanbolouki ◽  
Mehran Tehrani
Keyword(s):  
Carbon Nanotube ◽  
Viscoelastic Model ◽  
Viscoelastic Behavior ◽  
Energy Harvesters ◽  
Linear Behavior ◽  
Non Linear ◽  
Stretchable Conductors ◽  
Linear Viscoelastic Behavior ◽  
Linear Viscoelastic ◽  
Development And Validation

Coiled structures made from polymer and Carbon Nanotube (CNT) yarns are used as artificial muscles, stretchable conductors, and energy harvesters. The purpose of this work is to present our latest understanding of the mechanical behavior of these CNT-based structures. CNT yarns are fabricated by inserting twists in sheets spun from CNT forests. Over twisting the CNT yarns results in coiled CNT yarns, similar to a spring where the spring radius is comparable to the diameter of the CNT yarn. In this study, we explain the development and validation of a viscoelastic model, to capture damping and hysteresis in CNT yarns under quasi-static and dynamic loads. Confirmation of linear viscoelastic behavior of CNT yarns can lead us to the development of a model for coiled CNT yarns. Coiled CNT yarns, on the other hand, show a complex non-linear viscoelastic behavior. Possible mechanisms responsible for this non-linear behavior are discussed.

Development and Validation of a Non-Linear Viscoelastic Viscoplastic Stress Model for a PFCB/PVDF Fuel Cell Membrane

2012 ◽  
Author(s):  
Jessica A. Wright ◽  
Michael W. Ellis ◽  
David A. Dillard ◽  
Scott W. Case ◽  
Robert B. Moore ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
Numerical Models ◽  
Proton Exchange ◽  
Mechanical Degradation ◽  
Stress Model ◽  
Uniaxial Creep ◽  
Non Linear ◽  
Viscoelastic Modulus ◽  
Linear Viscoelastic ◽  
Development And Validation

Proton exchange membranes (PEMs) in operating fuel cells are subjected to varying thermal and hygral loads while under mechanical constraint imposed within the compressed stack. Swelling during hygrothermal cycles can result in residual in-plane tensile stresses in the membrane and lead to mechanical degradation or failure through thinning or pinhole development. Numerical models can predict the stresses resulting from applied loads based on material characteristics, thus helping to guide the development of more durable membrane materials. In this work, a non-linear viscoelastic stress model based on the Schapery constitutive formulation is used with a Zapas-Crissman viscoplastic term to describe the response of a novel membrane material comprised of a blend of perfluorocyclobutane (PFCB) ionomer and polyvinylidene fluoride (PVDF). Uniaxial creep and recovery tests are used to establish the time dependent linear viscoelastic modulus as well as the fitting parameters for the non-linear viscoelastic viscoplastic model. The stress model is implemented in a commercial finite element code, Abaqus®, to predict the response of a membrane subjected to mechanical loads. The stress model is validated by comparing predicted and experimental responses for membranes subjected to stress relaxation and multiple step creep loads in uniaxial tension.

scholarly journals Disentangling the Drivers of Obesity: An Analytical Framework Based on Socioeconomic and Intrapersonal Factors

2021 ◽  
Vol 8 ◽  
Author(s):  
Wisdom Dogbe ◽  
Melania Salazar-Ordóñez ◽  
Jose M. Gil
Keyword(s):  
Body Image ◽  
Body Weight ◽  
Body Image Dissatisfaction ◽  
Analytical Framework ◽  
Factors Affecting ◽  
Intrapersonal Factors ◽  
Linear Relationships ◽  
Holistic Review ◽  
Non Linear ◽  
And Gender

Obesity is increasing at exponential rates in developed economies despite the numerous policy interventions being implemented. The causes of obesity are multifactorial demanding a holistic review for targeted intervention. This study, therefore, provides a holistic overview of multiple factors affecting body weights i.e., socioeconomic and intrapersonal factors. We used data from a household and experimental survey carried out in Spain (Barcelona) in 2014. A non-linear path analysis was used considering the non-linear relationships that might exist between these factors and body weight. Results confirm non-linear relationships between some socioeconomic, intrapersonal factors and body weight. Among the intrapersonal factors, obesity is directly influenced by volitional control of obesity, attitude toward obese persons, holding a correct body image and body image dissatisfaction. Socioeconomic factors that have significant influence on obesity were age, education and gender. Risk attitudes do not correlate with obesity.

Development and validation of a non-linear k-ε model for flow over a full-scale building

2001 ◽  
Vol 4 (3) ◽  
pp. 177-196 ◽  
Author(s):  
N.G. Wright ◽  
G.J. Easom ◽  
R.J. Hoxey
Keyword(s):  
Full Scale ◽  
Non Linear ◽  
Development And Validation

International Law and Human Rights: Diverging and Converging Histories

2012 ◽  
Vol 6 (3) ◽  
Author(s):  
Jean H. Quataert
Keyword(s):  
Nineteenth Century ◽  
Human Rights ◽  
Social Movements ◽  
International Law ◽  
Analytical Framework ◽  
Global Politics ◽  
Global Context ◽  
Non Linear

AbstractThis article explores ways to think about the historical intersections of international law and human rights visions and principles in a global context. It catalogues an intertwining of new historiographies, notably the recent convergence of research interests of historians and international lawyers that draws attention to non-linear analyses; the role of social movements in understanding developments in the law; and the importance of historical contexts for interpretation. It sketches one promising analytical framework to assess the dynamic interconnections of international law and human rights from the mid-nineteenth century through the formal creation of the human rights system under U.N. auspices between 1945 and 1949. It concludes with a case study of gender tensions in more recent human rights global politics to provide historically-specific examples of the new possibilities of bringing historical interpretations to the study of international law and human rights.

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