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Institution

University of North Texas

EducationDenton, Texas, United States
About: University of North Texas is a education organization based out in Denton, Texas, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 11866 authors who have published 26984 publications receiving 705376 citations. The organization is also known as: Fight, North Texas & UNT.


Papers
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Journal ArticleDOI
TL;DR: This article explored the relationship between environmental scarcity and political violence in a global sample of countries, 1970-2006, and found that water abundance is positively correlated with political violence, and that this relationship is stronger in less developed, more agriculturally dependent societies.
Abstract: The dominant discourse on the security implications of climate change has asserted that acute environmental scarcity—such as that caused by drought—causes political violence. In contrast, we argue that there are good reasons why water scarcity might have a pacifying effect on armed conflict, and that political violence should be more prevalent during periods of comparatively better agro-climatic conditions. Political violence is more prevalent when basic needs are met and when the tactical environment is more conducive to attacks—conditions that hold when water is comparatively abundant. Empirically, this paper explores the relationship between environmental scarcity and political violence in a global sample of countries, 1970–2006. We find that water abundance is positively correlated with political violence, and that this relationship is stronger in less developed, more agriculturally dependent societies. These findings are robust to several different operationalizations of our variables. We conclude with a brief discussion of the policy implications of our findings.

134 citations

Journal ArticleDOI
TL;DR: Enhanced erosion resistance of HEA was attributed to its high work-hardening behavior and stable passivation film on the surface and no evidence of intergranular corrosion likely due to the absence of secondary precipitates.

134 citations

Journal ArticleDOI
TL;DR: This paper used the 1987 British Campaign Study data to investigate the structure of leader images and the determinants of electoral choice, and found that leader images had strong effects on party choice, including competence and responsiveness.
Abstract: Most research has deemphasized the influence of leader images on British voting. This paper uses the 1987 British Campaign Study data to investigate the structure of leader images and the determinants of electoral choice. Confirmatory factor analyses reveal two image dimensions--competence and responsiveness. These dimensions were associated more closely for the opposition leaders than for the prime minister. Multivariate analyses show that leader images had strong effects on party choice. Practical wisdom about party leaders should inform credible models of party support in an era of partisan dealignment.

134 citations

Journal ArticleDOI
TL;DR: In this paper, the activation energy of the intermetallic phases formed along a Sn-Ag eutectic solder/Cu interface during solid-state aging have been characterized and the activation energies of Cu3Sn and Cu6Sn5 growth have been calculated.
Abstract: Intermetallic phases formed along a Sn-Ag eutectic solder/Cu interface during solid-state aging have been characterized and the activation energies of Cu3Sn and Cu6Sn5 growth have been calculated. Diffusion couples consisting of Cu/ 96.5Sn-3.5Ag/Cu were aged at 110 to 208°C for 0 to 32 days. After aging, the Cu/ solder interfaces were examined using scanning electron microscopy and energy dispersive x-ray spectroscopy. The growth rate constants for each intermetallic layer were calculated assuming a simple parabolic diffusion-controlled growth model. The activation energy for Cu3Sn growth is 0.73 eV/atom and the activa-tion energy for Cu6Sn5 growth is 1.11 eV/atom.

134 citations

Journal ArticleDOI
TL;DR: In this paper, the formation and growth of intermetallics at the solder/substrate interface are factors affecting the solderability and reliability of electronic solder joints, and two mechanisms to explain the effects of the copper-containing and silver particles on the kinetics of the intermetallic formation are proposed.
Abstract: The formation and growth of intermetallics at the solder/substrate interface are factors affecting the solderability and reliability of electronic solder joints. This study was performed to better understand the diffusion behavior and microstructural evolution of Cu−Sn intermetallics at the composite solder/copper substrate interface for eutectic solder and solder alloys containing particle additions of Cu, Cu3Sn, Cu6Sn5, Ag, Au, and Ni. Annealing temperatures of 110 to 160°C were used with aging times of 0 to 64 days. The copper-containing composite solders generally formed thinner Cu6Sn5 layers, but thicker Cu3Sn layers than were formed by the eutectic solder alone. These copper-containing additions, therefore, resulted in increased activation energies for Cu6Sn5 formation and decreased activation energies for Cu3Sn formation as compared to the eutectic solder. The activation energy for Cu3Sn formation decreased relative to eutectic solder for silver and gold composite solders even though less Cu3Sn was formed at the substrate interface. Nickel and palladium drastically reduced the Cu3Sn thickness and increased the Cu6Sn5 thickness. However, the Cu6Sn5 contained a substantial volume fraction of voids close to the copper substrate. We propose two mechanisms to explain the effects of the copper-containing and silver particles on the kinetics of intermetallic formation. First, the particles act as tin-sinks which remove tin from the solder and decrease the amount of tin available for reaction at the solder/substrate interface. Second, the particles reduce the cross-sectional area available for tin diffusion, which also reduces the amount of tin available at the interface for reaction.

134 citations


Authors

Showing all 12053 results

NameH-indexPapersCitations
Steven N. Blair165879132929
Scott D. Solomon1371145103041
Richard A. Dixon12660371424
Thomas E. Mallouk12254952593
Hong-Cai Zhou11448966320
Qian Wang108214865557
Boris I. Yakobson10744345174
J. N. Reddy10692666940
David Spiegel10673346276
Charles A. Nelson10355740352
Robert J. Vallerand9830141840
Gerald R. Ferris9333229478
Michael H. Abraham8972637868
Jere H. Mitchell8833724386
Alan Needleman8637339180
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202390
2022300
20211,795
20201,769
20191,644
20181,484