393 research outputs found

    Old Deseret Live Stock Company

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    In the high country of the northern Wasatch Mountains lies what is left of one of the American West\u27s largest ranches. Deseret Live Stock Company was reputed at various times to be the largest private landholder in Utah and the single biggest producer of wool in the world. The ranch began as a sheep operation, but as it found success, it also ran cattle. Incorporated in the 1890s by a number of northern Utah ranchers who pooled their resources, the company was at the height of successful operations in the mid-twentieth century when a young Dean Frischknecht, bearing a recent degree in animal science, landed the job of sheep foreman. In his memoir, he recounts in detail how Deseret managed huge herds of livestock, vast lands, and rich wildlife, and he recalls through lively anecdotes how stockmen and their families lived and worked in the Wasatch Mountains and Skull Valley\u27s desert wintering grounds.https://digitalcommons.usu.edu/usupress_pubs/1116/thumbnail.jp

    Self-Consistent Field Theory of Multiply-Branched Block Copolymer Melts

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    We present a numerical algorithm to evaluate the self-consistent field theory for melts composed of block copolymers with multiply-branched architecture. We present results for the case of branched copolymers with doubly-functional groups for multiple branching generations. We discuss the stability of the cubic phase of spherical micelles, the A15 phase, as a consequence of tendency of the AB interfaces to conform to the polyhedral environment of the Voronoi cell of the micelle lattice.Comment: 12 pages, 10 includes figure

    Lamellae Stability in Confined Systems with Gravity

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    The microphase separation of a diblock copolymer melt confined by hard walls and in the presence of a gravitational field is simulated by means of a cell dynamical system model. It is found that the presence of hard walls normal to the gravitational field are key ingredients to the formation of well ordered lamellae in BCP melts. To this effect the currents in the directions normal and parallel to the field are calculated along the interface of a lamellar domain, showing that the formation of lamellae parallel to the hard boundaries and normal to the field correspond to the stable configuration. Also, it is found thet the field increases the interface width.Comment: 4 pages, 2 figures, submitted to Physical Review

    Towards a complexity theory for the congested clique

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    The congested clique model of distributed computing has been receiving attention as a model for densely connected distributed systems. While there has been significant progress on the side of upper bounds, we have very little in terms of lower bounds for the congested clique; indeed, it is now know that proving explicit congested clique lower bounds is as difficult as proving circuit lower bounds. In this work, we use various more traditional complexity-theoretic tools to build a clearer picture of the complexity landscape of the congested clique: -- Nondeterminism and beyond: We introduce the nondeterministic congested clique model (analogous to NP) and show that there is a natural canonical problem family that captures all problems solvable in constant time with nondeterministic algorithms. We further generalise these notions by introducing the constant-round decision hierarchy (analogous to the polynomial hierarchy). -- Non-constructive lower bounds: We lift the prior non-uniform counting arguments to a general technique for proving non-constructive uniform lower bounds for the congested clique. In particular, we prove a time hierarchy theorem for the congested clique, showing that there are decision problems of essentially all complexities, both in the deterministic and nondeterministic settings. -- Fine-grained complexity: We map out relationships between various natural problems in the congested clique model, arguing that a reduction-based complexity theory currently gives us a fairly good picture of the complexity landscape of the congested clique

    A 6D CAD Model for the Automatic Assessment of Building Sustainability

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    Current building assessment methods limit themselves in their environmental impact by failing to consider the other two aspects of sustainability: the economic and the social. They tend to be complex and costly to run, and therefore are of limited value in comparing design options. This paper proposes and develops a model for the automatic assessment of a building’s sustainability life cycle with the building information modelling (BIM) approach and its enabling technologies. A 6D CAD model is developed which could be used as a design aid instead of as a post-construction evaluation tool. 6D CAD includes 3D design as well as a fourth dimension (schedule), a fifth dimension (cost) and a sixth dimension (sustainability). The model can automatically derive quantities (5D), calculate economic (5D and 6D), environmental and social impacts (6D), and evaluate the sustainability performance of alternative design options. The sustainability assessment covers the life cycle stages of a building, namely material production, construction, operation, maintenance, demolition and disposal

    Self-Diffusion of a Polymer Chain in a Melt

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    Self-diffusion of a polymer chain in a melt is studied by Monte Carlo simulations of the bond fluctuation model, where only the excluded volume interaction is taken into account. Polymer chains, each of which consists of NN segments, are located on an L×L×LL \times L \times L simple cubic lattice under periodic boundary conditions, where each segment occupies 2×2×22 \times 2 \times 2 unit cells. The results for N=32,48,64,96,128,192,256,384N=32, 48, 64, 96, 128, 192, 256, 384 and 512 at the volume fraction ϕ0.5\phi \simeq 0.5 are reported, where L=128L = 128 for N256N \leq 256 and L=192 for N384N \geq 384. The NN-dependence of the self-diffusion constant DD is examined. Here, DD is estimated from the mean square displacements of the center of mass of a single polymer chain at the times larger than the longest relaxation time. From the data for N=256N = 256, 384 and 512, the apparent exponent xdx_{\rm d}, which describes the apparent power law dependence of DD on NN as DNxdD \propto N^{- x_{\rm d}}, is estimated as xd2.4x_{\rm d} \simeq 2.4. The ratio Dτ/D \tau / seems to be a constant for N=192,256,384N = 192, 256, 384 and 512, where τ\tau and denote the longest relaxation time and the mean square end-to-end distance, respectively.Comment: 4 pages, 3 figures, submitted to J. Phys. Soc. Jp
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