University of Akron

About: University of Akron is a education organization based out in Akron, Ohio, United States. It is known for research contribution in the topics: Polymer & Polymerization. The organization has 17401 authors who have published 29127 publications receiving 702386 citations. The organization is also known as: The University of Akron.

Causes of Corruption: History, Geography, and Government

Abstract: Corruption, which remains a serious problem in many countries, has prompted considerable research in recent years. This paper adds to the extant literature with insights on factors influencing corrupt activity. Using cross-country data for about 100 nations, the roles of national history, geography, and government are examined to see how they affect conditions for corruption, both qualitatively and quantitatively. The innovative aspects of this research include use of a wide set of historical, geographical, and governmental determinants of corruption, as well as detailed assessment of several previously considered determinants. The main issues addressed are the effects of the size and scope of government on the incidence of corruption across countries, and the significance of historical and geographic factors in corruption. Regarding the first question, the authors find the size and scope of government can significantly affect corruption. On the second, it is shown that historical institutional inertia in older countries and new rent-seeking opportunities in younger nations can encourage corruption, while certain geographic factors can mitigate corruption. The paper ends with discussion aimed at the policymaker.

Controls on trace metal authigenic enrichment in reducing sediments: Insights from modern oxygen-deficient settings

Abstract: Any effort to reconstruct Earth history using variations in authigenic enrichments of redox-sensitive and biogeochemically important trace metals must rest on a fundamental understanding of their modern oceanic and sedimentary geochemistry. Further, unravelling the multiple controls on sedimentary enrichments requires a multi-element approach. Of the range of metals studied, most is known about the behavior of Fe, Mn, and Mo. In this study, we compare the authigenic enrichment patterns of these elements with a group whose behavior is not as well defined (Cd, Cu, Zn, and Ni) in three oxygen-poor settings: the Black Sea, the Cariaco Basin (Venezuela), and the Peru Margin. These three settings span a range of biogeochemical environments, allowing us to isolate the different controls on sedimentary enrichment. Our approach, relying on the covariation of elemental enrichment factors [EF, defined for element X as: EFX = (X/Al)sample/(X/Al)lithogenic], has previously been applied to Mo and U to elucidate paleoenvironmental information on, for example, benthic redox conditions, the particulate shuttle, and the evolution of water mass chemistry. We find two key controls on trace metal enrichment. First, the concentration of an element in the lithogenic background sediment (used in calculating EFX) controls the magnitude of potential enrichment. Maximum enrichment factors of 376 and 800 are calculated for Mo (∼1 ppm in detrital sediments) and Cd (∼0.3 ppm), respectively, compared to values not greater than 17 in any setting for the other five metals (∼45 ppm to ∼4.5 wt.% in detrital sediments). Second, there is a relationship between the aqueous concentration of the element in overlying seawater and its degree of enrichment in the sediment. We further identify four important processes for delivery of trace metals to the sediment. These are: (1) cellular uptake (especially important for Zn and Cd), (2) interaction/co-precipitation with sulfide (Mo, Cu, and Cd), (3) passive scavenging via the traditional particulate shuttle (Mo, Ni, and Cu), and (4) an association with the benthic Fe redox shuttle (Mn, Ni). Finally, we summarize the oceanic mass balance of Cd and Mo and place the first constraints on the contribution of reducing sediments to the oceanic mass balance of Cu, Zn, and Ni. We show that reducing sediments are the ultimate repository for up to half the total output flux of these elements from the oceanic dissolved pool.

Simulations of inorganic–bioorganic interfaces to discover new materials: insights, comparisons to experiment, challenges, and opportunities

Abstract: Natural and man-made materials often rely on functional interfaces between inorganic and organic compounds. Examples include skeletal tissues and biominerals, drug delivery systems, catalysts, sensors, separation media, energy conversion devices, and polymer nanocomposites. Current laboratory techniques are limited to monitor and manipulate assembly on the 1 to 100 nm scale, time-consuming, and costly. Computational methods have become increasingly reliable to understand materials assembly and performance. This review explores the merit of simulations in comparison to experiment at the 1 to 100 nm scale, including connections to smaller length scales of quantum mechanics and larger length scales of coarse-grain models. First, current simulation methods, advances in the understanding of chemical bonding, in the development of force fields, and in the development of chemically realistic models are described. Then, the recognition mechanisms of biomolecules on nanostructured metals, semimetals, oxides, phosphates, carbonates, sulfides, and other inorganic materials are explained, including extensive comparisons between modeling and laboratory measurements. Depending on the substrate, the role of soft epitaxial binding mechanisms, ion pairing, hydrogen bonds, hydrophobic interactions, and conformation effects is described. Applications of the knowledge from simulation to predict binding of ligands and drug molecules to the inorganic surfaces, crystal growth and shape development, catalyst performance, as well as electrical properties at interfaces are examined. The quality of estimates from molecular dynamics and Monte Carlo simulations is validated in comparison to measurements and design rules described where available. The review further describes applications of simulation methods to polymer composite materials, surface modification of nanofillers, and interfacial interactions in building materials. The complexity of functional multiphase materials creates opportunities to further develop accurate force fields, including reactive force fields, and chemically realistic surface models, to enable materials discovery at a million times lower computational cost compared to quantum mechanical methods. The impact of modeling and simulation could further be increased by the advancement of a uniform simulation platform for organic and inorganic compounds across the periodic table and new simulation methods to evaluate system performance in silico.

Stress Relaxation of Natural and Synthetic Rubber Stocks

Abstract: Measurements of stress decay as a function of time made at constant elongation on thin bands of gum and tread type natural rubber (Hevea), Neoprene, Butyl, Buna S, and Butaprene N stocks indicate that both secondary and primary bond relaxation occur. Practically complete relaxation is observed to take place in the experimental time (about 100 hours) at temperatures at and above 100 degrees C. The manner in which the rate of relaxation depends on temperature and the fact that the rate is independent of elongation and of the presence of carbon black in the vulcanizate indicate that stress decay is caused by a definite chemical reaction which deteriorates the rubber structure, and oxidative scission is suggested as the mechanism of deterioration of the primary bonds. The stress relaxation data, obtained over a temperature range from −50°C to +150°C, appear to verify modern concepts of the structure of elastomers. Theoretical equations are derived which give very good agreement with the observed relaxation da...

An Information‐processing Perspective on Leadership and Culture: A Case for Connectionist Architecture

Abstract: Un mode`le de la relation entre la culture et le leadership est pre´sente´ dans cet article; ce mode`le est centre´ sur le traitement de l’information. Nous estimons qu’un re´seau connectionniste s’impose pour une bonne compre´hension de la faµon dont la culture et le leadership influencent les re´actions et la comprotement du suiveur, ce qui nous diffe´rencie des travaux ante´rieurs dans ce domaine. On examine brie`vement les structure connectionnistes en remarquant qu’il y a recouvrement entre la conceptualisation des sche´mas inclus dans ces structures et les re´flexions actuelles sur les sche´mas concernant la culture et le leadership. Ce mode`le est suffisamment souple pour expliquer les processus cognitivement efficients qui e´mergent consciemment ou subconsciemment. En outre, il peut rendre compte de la sensibilite´ a` l’information (provenant de la situation) des sche´mas du leadership et des syste`mes culturels. On traite enfin du caracte`re critique de la notion de concept de soi dans la compre´hension des processus a` travers lesquels culture et leadership interagissent pour influencer les re´action et la conduite des suiveurs.