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.

Worldwide evidence of a unimodal relationship between productivity and plant species richness

Abstract: The search for predictions of species diversity across environmental gradients has challenged ecologists for decades The humped-back model (HBM) suggests that plant diversity peaks at intermediate productivity; at low productivity few species can tolerate the environmental stresses, and at high productivity a few highly competitive species dominate Over time the HBM has become increasingly controversial, and recent studies claim to have refuted it Here, by using data from coordinated surveys conducted throughout grasslands worldwide and comprising a wide range of site productivities, we provide evidence in support of the HBM pattern at both global and regional extents The relationships described here provide a foundation for further research into the local, landscape, and historical factors that maintain biodiversity

Oxygen Vacancy Promoting Dimethyl Carbonate Synthesis from CO2 and Methanol over Zr-Doped CeO2 Nanorods

Abstract: The synthesis of dimethyl carbonate (DMC) from CO2 and methanol by Zr-doped CeO2 nanorods with different ratios of Zr/Ce has been studied at 6.8 MPa and 140 °C. The catalysts were characterized ext...

Adhesion and Strength of Viscoelastic Solids. Is There a Relationship between Adhesion and Bulk Properties

Abstract: Strength of adhesion depends upon the rheology of an adhesive as well as upon its interaction with a substrate. This is shown by studies using model joints prepared with different amounts of interlinking between two rubber sheets. The fracture energy G per unit of interfacial area appears to be a product of two terms: G = Go [1 + f(R,T)], where Go is the intrinsic (chemical) strength of the interface and f(R,T), usually much larger than unity, reflects energy dissipated viscoelastically within the adherends at a crack speed R and temperature T. Values of Go range from virtually zero for nonbonded sheets up to the threshold tear strength of rubber, 50−80 J/m2, in proportion to the density of interfacial bonds. Values of G are as much as 1000× greater at high speeds and low temperatures. Like adhesion, the tear strength of a soft rubbery solid is also increased by internal energy losses and shows the same marked dependence upon rate of tearing. By comparing the rate R at which tear strength increases by a ...

Full-field representation of discretely sampled surface deformation for displacement and strain analysis

Abstract: A detailed evaluation of the feasibility of determining displacements and displacement gradients from measured surface displacement fields is presented. An improved methodology for both the estimation and elimination of noise is proposed. The methodology is used to analyze the gradients for three tests: (1) uniform rotation, (2) uniform strain, and (3) crack-tip displacement fields. Results of the study indicate that the proposed methodology can be used to extract the underlying two-dimensional displacements and their corresponding gradients from the noisy data with reasonable accuracy. Specifically, it is shown that (a) the digital correlation method for acquiring displacement fields has an error in strain of approximately 150 μ strain at each point, (b) the average strain in a region of uniform strain has much less error, typically on the order of 20 μ strain, (c) the displacement ‘nolse’ present in digital correlation is very small, approximately 0.01 pixels, (d) the proposed methodology for reducing noise in the data is essential to the accurate evaluation of displacement gradients and (e) the successful evaluation of displacement and displacement gradients for all three cases indicates that the proposed methodology can be used both to quantify the displacement fields and to reasonably estimate the overall gradient trends.