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1.
J Appl Psychol ; 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38619472

RESUMO

Multiperspective frameworks, such as the social relations model, socioanalytic theory, the realistic accuracy model, the self-other knowledge asymmetry model, and the trait-reputation-identity model, have advanced understanding of personality over the last 40 years. Due to a resurgence of interest in multiperspective research on personality and other constructs in organizational psychology, we conducted an integrative conceptual review of these specific multirater frameworks and their application in work settings. Our review identifies similarities and differences in these frameworks and suggests that they collectively represent an invaluable resource for personality researchers and the broader field of organizational psychology. Through our review, we distinguish multiperspective frameworks from similar approaches (e.g., multirater designs), track the evolution of these frameworks, and leverage current applications of these frameworks to craft a future research agenda. Our review serves as a roadmap to help scholars apply multiperspective logic more thoroughly and systematically in personality research and beyond. We close with a discussion of practical implications. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

2.
Materials (Basel) ; 15(1)2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-35009537

RESUMO

The microstructural transformations of binary nanometallic multilayers (NMMs) to equiaxed nanostructured materials were explored by characterizing a variety of nanoscale multilayer films. Four material systems of multilayer films, Hf-Ti, Ta-Hf, W-Cr, and Mo-Au, were synthesized by magnetron sputtering, heat treated at 1000 °C, and subsequently characterized by transmission electron microscopy. Binary systems were selected based on thermodynamic models predicting stable nanograin formation with similar global compositions around 20-30 at.%. All NMMs maintained nanocrystalline grain sizes after evolution into an equiaxed structure, where the systems with highly mobile incoherent interfaces or higher energy interfaces showed a more significant increase in grain size. Furthermore, varying segregation behaviors were observed, including grain boundary (GB) segregation, precipitation, and intermetallic formation depending on the material system selected. The pathway to tailored microstructures was found to be governed by key mechanisms and factors as determined by a film's initial characteristics, including global and local composition, interface energy, layer structure, and material selection. This work presents a global evaluation of NMM systems and demonstrates their utility as foundation materials to promote tailored nanomaterials.

3.
Adv Mater ; 34(27): e2200354, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35512110

RESUMO

Targeted doping of grain boundaries is widely pursued as a pathway for combating thermal instabilities in nanocrystalline metals. However, certain dopants predicted to produce grain-boundary-segregated nanocrystalline configurations instead form small nanoprecipitates at elevated temperatures that act to kinetically inhibit grain growth. Here, thermodynamic modeling is implemented to select the Mo-Au system for exploring the interplay between thermodynamic and kinetic contributions to nanostructure stability. Using nanoscale multilayers and in situ transmission electron microscopy thermal aging, evolving segregation states and the corresponding phase transitions are mapped with temperature. The microstructure is shown to evolve through a transformation at lower homologous temperatures (<600 °C) where solute atoms cluster and segregate to the grain boundaries, consistent with predictions from thermodynamic models. An increase in temperature to 800 °C is accompanied by coarsening of the grain structure via grain boundary migration but with multiple pinning events uncovered between migrating segments of the grain boundary and local solute clustering. Direct comparison between the thermodynamic predictions and experimental observations of microstructure evolution thus demonstrates a transition from thermodynamically preferred to kinetically inhibited nanocrystalline stability and provides a general framework for decoupling contributions to complex stability transitions while simultaneously targeting a dominant thermal stability regime.

4.
Sci Rep ; 6: 26870, 2016 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-27230299

RESUMO

The sensitization and subsequent intergranular corrosion of Al-5.3 wt.% Mg alloy has been shown to be an important factor in stress corrosion cracking of Al-Mg alloys. Understanding sensitization requires the review of grain boundary character on the precipitation process which can assist in developing and designing alloys with improved corrosion resistance. This study shows that the degree of precipitation in Al-Mg alloy is dependent on grain boundary misorientation angle, adjacent grain boundary planes and grain boundary types. The results show that the misorientation angle is the most important factor influencing precipitation in grain boundaries of the Al-Mg alloy. Low angle grain boundaries (≤15°) have better immunity to precipitation and grain boundary acid attack. High angle grain boundaries (>15°) are vulnerable to grain boundary acid attack. Grain boundaries with adjacent plane orientations near to {100} have potential for immunity to precipitation and grain boundary acid attack. This work shows that low Σ (Σ ≤ 29) coincident site lattice (CSL) grain boundaries have thinner ß precipitates. Modified nitric acid mass loss test and polarization test demonstrated that the global corrosion resistance of sputtered Al-Mg alloy is enhanced. This may be attributed to the increased fractions of low Σ (Σ ≤ 29) CSL grain boundaries after sputtering.

5.
Sci Rep ; 6: 22568, 2016 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-26932846

RESUMO

The response of amorphous steels to shock wave compression has been explored for the first time. Further, the effect of partial devitrification on the shock response of bulk metallic glasses is examined by conducting experiments on two iron-based in situ metallic glass matrix composites, containing varying amounts of crystalline precipitates, both with initial composition Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4. The samples, designated SAM2X5-600 and SAM2X5-630, are X-ray amorphous and partially crystalline, respectively, due to differences in sintering parameters during sample preparation. Shock response is determined by making velocity measurements using interferometry techniques at the rear free surface of the samples, which have been subjected to impact from a high-velocity projectile launched from a powder gun. Experiments have yielded results indicating a Hugoniot Elastic Limit (HEL) to be 8.58 ± 0.53 GPa for SAM2X5-600 and 11.76 ± 1.26 GPa for SAM2X5-630. The latter HEL result is higher than elastic limits for any BMG reported in the literature thus far. SAM2X5-600 catastrophically loses post-yield strength whereas SAM2X5-630, while showing some strain-softening, retains strength beyond the HEL. The presence of crystallinity within the amorphous matrix is thus seen to significantly aid in strengthening the material as well as preserving material strength beyond yielding.

6.
Tissue Eng Part C Methods ; 18(12): 968-75, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22656195

RESUMO

The study of the mechanical behavior of soft biological materials presents many challenges due to the materials' time-dependent mechanical response as well as inherent size and shape limitations. In this study, by using agar as a surrogate material for soft tissues, the effects of these limitations upon standardized macroscale dynamic compression protocols are compared to dynamic nanoindentation procedures. Both techniques are then applied to dynamically test porcine sclera tissue, showing a significant difference in recorded loss and storage modulus values between the two methodologies. Additionally, the tissues of the porcine eye wall are characterized with macrocompression in their layered in vivo arrangement. The overall constraints of standardized macroscale tests for dynamic mechanical characterization of thin and soft biological tissues are discussed.


Assuntos
Elasticidade , Nanotecnologia , Viscosidade
7.
Nano Lett ; 9(3): 1158-63, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19193021

RESUMO

The evolution of the grain structure, internal strain, and the lattice misorientations of nanoporous gold during dealloying of bulk (3D) Ag-Au alloy samples was studied by various in situ and ex situ X-ray diffraction techniques including powder and Laue diffraction. The experiments reveal that the dealloying process preserves the original crystallographic structure but leads to a small spread in orientations within individual grains. Initially, most grains develop in-plane tensile stresses, which are partly released during further dealloying. Simultaneously, the feature size of the developing nanoporous structure increases with increasing dealloying time. Finally, microdiffraction experiments on dealloyed micron-sized nanoporous pillars reveal significant surface damage introduced by focused ion beam milling.

8.
Nano Lett ; 6(10): 2379-82, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17034115

RESUMO

Recent nanomechanical tests on submicron metal columns and wires have revealed a dramatic increase in yield strength with decreasing sample size. Here, we demonstrate that nanoporous metal foams can be envisioned as a three-dimensional network of ultrahigh-strength nanowires, thus bringing together two seemingly conflicting properties: high strength and high porosity. Specifically, we characterized the size-dependent mechanical properties of nanoporous gold using a combination of nanoindentation, column microcompression, and molecular dynamics simulations. We find that nanoporous gold can be as strong as bulk Au, despite being a highly porous material, and that the ligaments in nanoporous gold approach the theoretical yield strength of Au.


Assuntos
Ouro/química , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Força Compressiva , Elasticidade , Dureza , Teste de Materiais , Mecânica , Conformação Molecular , Tamanho da Partícula , Porosidade , Estresse Mecânico , Propriedades de Superfície , Resistência à Tração
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