Atomistic Study of the Thermal Stress due to Twin Boundaries

There is compelling evidence for the critical role of twin boundaries in imparting the extraordinary combination of strength and ductility to nanotwinned metals. This paper presents a study of the thermal expansion of coherent twin boundaries (CTBs) at finite temperature by way of atomistic simulations. The simulations reveal that for all twin boundary spacings d, the thermal expansion induced stress varies as 1/d. This surprisingly long-range effect is attributed to the inhomogeneity in the thermal expansion coefficient due to the interfacial regions.

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Coaching on the Talent Pathway: Understanding the Influence of Developmental Experiences on Coaching Philosophy

International Sport Coaching Journal ◽

10.1123/iscj.2019-0099 ◽

2020 ◽

pp. 1-12

Author(s):

Graham G. Williams ◽

Áine MacNamara

Keyword(s):

Youth Development ◽

Critical Role ◽

Youth Sport ◽

Individual Development ◽

Compelling Evidence ◽

High Quality ◽

Developmental Experiences ◽

Youth Athletes ◽

Youth Athlete

There is compelling evidence supporting the critical role of high-quality coaching practice in supporting talented youth athletes through and beyond the talent pathway. The purpose of this study was to explore the coaching philosophies of ex-talent pathway athletes and how the meaning and purpose of their coaching in a talent pathway was influenced by their previous pathway experience. Nine participants were purposefully sampled based on their prior involvement as a youth athlete in a talent pathway and current involvement coaching in a talent pathway. The participants identified how their pathway experience influenced their coaching philosophy and applied coaching practice. Specifically, the participants described how their own youth sport experience influenced their current coaching practice through the formation of a developmental coaching philosophy, through their applied coaching practice orientated towards supporting individual development, and by using their previous pathway experience to support coaching success. These findings suggest that the philosophy underpinning talent pathway coaches’ practice was influenced by their own pathway experience, and the purpose of their practice was orientated to positively impact youth development for and beyond sport. Thus, talent pathways in sport have the capability to be recognised as positively influencing the developmental experiences of future coaching practitioners.

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Role of Heat Expansion with a Series of Ionic Liquids: The Case for Isochoric Thermoelectric Generators and Minimal Steric Repulsion

Entropy ◽

10.3390/e21111086 ◽

2019 ◽

Vol 21 (11) ◽

pp. 1086

Author(s):

Marcus Jackson ◽

Robert Engel ◽

Luat Vuong

Keyword(s):

Thermal Expansion ◽

Ionic Liquids ◽

Critical Role ◽

Intramolecular Interactions ◽

Large Temperature ◽

Thermoelectric Generators ◽

Steric Repulsion ◽

Seebeck Coefficients ◽

Heat Expansion

The role of convection in liquid thermoelectric cells may be difficult to predict because the inter- and intramolecular interactions are not currently incorporated into thermodynamic models. Here, we study the thermoelectric response of a series of five anhydrous 1-methyl-3- alkylimidazolium halide ionic liquids with varied chain length and counterion in a high-aspect-ratio, horizontal-temperature-gradient geometry, where convection is minimal. While a canonical constant-volume thermodynamic model predicts that the longer aliphatic groups exhibit larger Seebeck coefficients, we instead measure the opposite: Longer aliphatic chains correlate with lower densities and greater heat expansion, stronger intermolecular associations, stronger steric repulsion, and lower Seebeck coefficients. As evidence of the critical role of thermal expansion, we measure that the Seebeck effect is nonlinear: Values of −2.8 mV/K with a 10 K temperature difference and −1.8 mV/K with a 50 K difference are measured with ether ion. Our results indicate that steric repulsion and heat expansion are important considerations in ionic liquid design; with large temperature differences, the Seebeck coefficient correlates negatively with heat expansion. Our results suggest that Seebeck values will improve if thermal expansion is limited in a pressurized, isochoric, convection-free design.

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Ion exchange strengthening and thermal expansion of glasses: Common origin and critical role of network connectivity

Journal of Non-Crystalline Solids ◽

10.1016/j.jnoncrysol.2016.10.027 ◽

2017 ◽

Vol 455 ◽

pp. 70-74 ◽

Cited By ~ 17

Author(s):

Mengyi Wang ◽

Bu Wang ◽

N M Anoop Krishnan ◽

Yingtian Yu ◽

Morten M. Smedskjaer ◽

...

Keyword(s):

Thermal Expansion ◽

Ion Exchange ◽

Critical Role ◽

Network Connectivity ◽

Common Origin

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Carbide precipitation and chromium depletion on coherent twin boundaries in deformed 304 stainless steels

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130717 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1216-1217

Author(s):

A.H. Advani ◽

L.E. Murr ◽

D.J. Matlock ◽

W.W. Fisher ◽

P.M. Tarin ◽

...

Keyword(s):

Grain Boundaries ◽

Stainless Steels ◽

Interfacial Free Energy ◽

Carbide Precipitation ◽

Twin Boundaries ◽

Invariant Structure ◽

Heat Treated ◽

Constant Structure ◽

Cr Depletion

Coherent annealing-twin boundaries are constant structure and energy interfaces with an average interfacial free energy of ∼19mJ/m2 versus ∼210 and ∼835mJ/m2 for incoherent twins and “regular” grain boundaries respectively in 304 stainless steels (SS). Due to their low energy, coherent twins form carbides about a factor of 100 slower than grain boundaries, and limited work has also shown differences in Cr-depletion (sensitization) between twin versus grain boundaries. Plastic deformation, may, however, alter the kinetics and thermodynamics of twin-sensitization which is not well understood. The objective of this work was to understand the mechanisms of carbide precipitation and Cr-depletion on coherent twin boundaries in deformed SS. The research is directed toward using this invariant structure and energy interface to understand and model the role of interfacial characteristics on deformation-induced sensitization in SS. Carbides and Cr-depletion were examined on a 20%-strain, 0.051%C-304SS, heat treated to 625°C-4.5h, as described elsewhere.

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The Role of the SLP in Autism Spectrum Disorder Screening and Assessment

Perspectives on Language Learning and Education ◽

10.1044/lle15.2.50 ◽

2008 ◽

Vol 15 (2) ◽

pp. 50-59 ◽

Cited By ~ 1

Author(s):

Amy Philofsky

Keyword(s):

Language Development ◽

Critical Role ◽

Children With Autism ◽

Autism Spectrum ◽

Children With Asd ◽

Prevalence Estimates ◽

Notable Increase ◽

Screening Assessment ◽

Critical Components

AbstractRecent prevalence estimates for autism have been alarming as a function of the notable increase. Speech-language pathologists play a critical role in screening, assessment and intervention for children with autism. This article reviews signs that may be indicative of autism at different stages of language development, and discusses the importance of several psychometric properties—sensitivity and specificity—in utilizing screening measures for children with autism. Critical components of assessment for children with autism are reviewed. This article concludes with examples of intervention targets for children with ASD at various levels of language development.

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