13,802 research outputs found

    ‘Hybrid Transitions: Combining Biomass and Solar Energy for Water Heating in Public Bathhouses’

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    This paper presents and evaluates initiatives taken in Morocco to reduce wood consumption, improve energy efficiency and reduce deforestation due to the operation of hammams (Turkish baths). First, the paper examines the vernacular energy systems used in heritage hammams and their lessons of sustainability. Second, it presents the problems associated with the new hammam furnaces and how they replicate vernacular systems. Third, the various initiatives for more energy efficient systems are presented. These include hybrid solar/biomass hammam systems. The paper evaluates the opportunities for addressing local and global concerns over deforestation and CO2 emissions and discusses various difficulties and challenges

    Dynamic Co-Existence of Company-Owned and Franchised Outlets Within a Company: A Framework of the Franchisor\u27s Perspective

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    Why and how do company-owned and franchised outlets simultaneously exist within the same organization? The purpose of this article is to integrate a variety of theories on this interesting retail phenomenon into a broader theoretical framework based on the political-economy paradigm. This paper attempts to integrate the perspectives of several theories that previously have been considered competing models of a single reality--the access-to-capital viewpoint, transaction cost analysis, the population ecology perspective, and power-dependence-conflict arguments--into a broader perspective that utilizes intra-firmfactors and the internal and external economies and polities of the political-economy paradigm. A model depicting this integration is set forth and nineteen research propositions stemming from this model are proposed

    The asymptotics of the moving contact line: cracking an old nut

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    This article has been published in a revised form in Journal of Fluid Mechanics https://doi.org/10.1017/jfm.2014.702. This version is free to view and download for private research and study only. Not for re-distribution, re-sale or use in derivative works. © Cambridge University Press.For contact line motion where the full Stokes flow equations hold, full matched asymptotic solutions using slip models have been obtained for droplet spreading and more general geometries. These solutions to the singular perturbation problem in the slip length, however, all involve matching through an intermediate region that is taken to be separate from the outer-inner regions. Here, we show that the intermediate region is in fact an overlap region representing extensions of both the outer and the inner region, allowing direct matching to proceed. In particular, we investigate in detail how a previously seen result of the matching of the cubes of the free surface slope is justified in the lubrication setting. We also extend this two-region direct matching to the more general Stokes flow case, offering a new perspective on the asymptotics of the moving contact line problem

    SNS Timing System

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    This poster describes the timing system being designed for Spallation Neutron Source being built at Oak Ridge National lab

    Binding potentials for vapour nanobubbles on surfaces using density functional theory

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    We calculate density profiles of a simple model fluid in contact with a planar surface using density functional theory (DFT), in particular for the case where there is a vapour layer intruding between the wall and the bulk liquid. We apply the method of Hughes et al. [J. Chem. Phys. 142, 074702 (2015)] to calculate the density profiles for varying (specified) amounts of the vapour adsorbed at the wall. This is equivalent to varying the thickness hh of the vapour at the surface. From the resulting sequence of density profiles we calculate the thermodynamic grand potential as hh is varied and thereby determine the binding potential as a function of hh. The binding potential obtained via this coarse-graining approach allows us to determine the disjoining pressure in the film and also to predict the shape of vapour nano-bubbles on the surface. Our microscopic DFT based approach captures information from length scales much smaller than some commonly used models in continuum mechanics.Comment: 15 pages, 15 figure

    Plasma membrane association by N-acylation governs PKG function in Toxoplasma gondii

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    ABSTRACT Cyclic GMP (cGMP)-dependent protein kinase (protein kinase G [PKG]) is essential for microneme secretion, motility, invasion, and egress in apicomplexan parasites, However, the separate roles of two isoforms of the kinase that are expressed by some apicomplexans remain uncertain. Despite having identical regulatory and catalytic domains, PKG I is plasma membrane associated whereas PKG II is cytosolic in Toxoplasma gondii . To determine whether these isoforms are functionally distinct or redundant, we developed an auxin-inducible degron (AID) tagging system for conditional protein depletion in T. gondii . By combining AID regulation with genome editing strategies, we determined that PKG I is necessary and fully sufficient for PKG-dependent cellular processes. Conversely, PKG II is functionally insufficient and dispensable in the presence of PKG I . The difference in functionality mapped to the first 15 residues of PKG I , containing a myristoylated Gly residue at position 2 that is critical for membrane association and PKG function. Collectively, we have identified a novel requirement for cGMP signaling at the plasma membrane and developed a new system for examining essential proteins in T. gondii . IMPORTANCE Toxoplasma gondii is an obligate intracellular apicomplexan parasite and important clinical and veterinary pathogen that causes toxoplasmosis. Since apicomplexans can only propagate within host cells, efficient invasion is critically important for their life cycles. Previous studies using chemical genetics demonstrated that cyclic GMP signaling through protein kinase G (PKG)-controlled invasion by apicomplexan parasites. However, these studies did not resolve functional differences between two compartmentalized isoforms of the kinase. Here we developed a conditional protein regulation tool to interrogate PKG isoforms in T. gondii . We found that the cytosolic PKG isoform was largely insufficient and dispensable. In contrast, the plasma membrane-associated isoform was necessary and fully sufficient for PKG function. Our studies identify the plasma membrane as a key location for PKG activity and provide a broadly applicable system for examining essential proteins in T. gondii . </jats:p
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