633 research outputs found
Evaluation of the Tensile, Water Diffusion, and Water Hydrolysis Properties of Graphene Oxide/Polyamide-11 Composites and Their Synthesis
Graphene oxide (GO) is a nanoparticle derived from pristine graphene and shows increasing promise for applications as a reinforcement material for polymer composites. Pristine graphene forms the basal plane of graphite and is one of the strongest materials known to man and exhibits excellent gas barrier properties. Polyamide-11 (PA-11) is a specialty polymer of the Nylon class and is commonly used in offshore oil pipes due to its excellent mechanical properties and superior resistance to hydrolysis compared to other polyamides. However, degradation by hydrolysis of PA-11 in the aqueous environments of these pipes still poses significant safety and budget concerns. This paper explores the advantages in tensile, water diffusion, and water hydrolysis properties of GO/PA-11 composites. Two separate batches of composites were made by polymerizing GO/11-Aminoundecanoic Acid dispersions in-situ. The batch with a faster heating rate during polymerization showed superior tensile properties at low GO concentrations and a lower diffusion coefficient at higher GO concentrations. The batch with the slower heating rate showed an improved equilibrium molecular weight at low GO concentrations but the tensile properties showed no improvement compared to the neat system
LEADING INDICATORS OF REGIONAL COTTON ACREAGE RESPONSE: STRUCTURAL AND TIME SERIES MODELING RESULTS
Resurgent cotton production compels better acreage forecasts for planning seed, chemical, and other input requirements. Structural models describe leading acreage response indicators, and forecasts are compared to time-series models. Cotton price, loan rate, deficiency payments, lagged corn acreage, the PIK program, and previous cotton yield significantly influence cotton acreage response.resurgent cotton production, cotton acreage, Crop Production/Industries,
LEADING INDICATORS FOR REGIONAL COTTON RESPONSE: STRUCTURAL AND TIME SERIES MODELING RESULTS
Resurging southeastern cotton production compels better cotton acreage forecasts for planning seed, chemical, and other input requirements. Structural models describe leading acreage response indicators, and forecasts are compared time-series models. Cotton price, loan rate, deficiency payments, lagged corn acreage, the PIK program, and previous cotton yield significantly influence response.Crop Production/Industries,
Ислам антропологии
Research on ‘Muslim societies’ is a controversial topic in the present, particularly given the US army’s current employment of anthropological experts in war zones under military occupation. In 2006 the UK Foreign Office, too, sought to include anthropologists in its worldwide research project entitled ‘Combating Terrorism by Countering Radicalization’, with grants given outside the normal process of research funding and differently assessed. In this article, I immodestly argue for how the discipline of anthropology should apprehend and analyse Islam in the present political context. The paper claims that anthropological research provides an antidote to the Islamophobia of much talk about Islam in the Australian public sphere, an Islamophobia originating not only from the right but from some leftists and feminists as well.Исследования «мусульманских обществ» в наше время вызывают дискуссии, особенно с учётом того, что армия США стала привлекать экспертов-антропологов к работе в зонах боевых действий в условиях военной оккупации. В 2006 г. МИД Великобритании также стремилось включить антропологов в свой глобальный исследовательский проект «Борьба с терроризмом через противодействие радикализации», выдавая гранты в обход нормального процесса финансирования исследований и с иными квалификационными требованиями. В этой статье я открыто отстаиваю свою точку зрения на то, как антропологическая наука должна воспринимать и анализировать ислам в современном политическом контексте. Я утверждаю, что антропологические исследования дают противоядие от исламофобии, о которой много говорят в австралийском обществе в связи с исламом — исламофобии, исходящей не только от правых, но также и от некоторых левых и феминисток
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A simple finite volume method for adaptive viscous liquids
© Christopher Batty & Ben Houston | ACM 2011. This is the author's version of the work. It is posted here for your personal use. Not for redistribution. The definitive Version of Record was published in SCA '11: Proceedings of the 2011 ACM SIGGRAPH/Eurographics Symposium on Computer Animation, http://dx.doi.org/10.1145/2019406.2019421We present the first spatially adaptive Eulerian fluid animation method to support challenging viscous liquid effects such as folding, coiling, and variable viscosity. We propose a tetrahedral node-based embedded finite volume method for fluid viscosity, adapted from popular techniques for Lagrangian deformable objects. Applied in an Eulerian fashion with implicit integration, this scheme stably and efficiently supports high viscosity fluids while yielding symmetric positive definite linear systems. To integrate this scheme into standard tetrahedral mesh-based fluid simulators, which store normal velocities on faces rather than velocity vectors at nodes, we offer two methods to reconcile these representations. The first incorporates a mapping between different degrees of freedom into the viscosity solve itself. The second uses a FLIP-like approach to transfer velocity data between nodes and faces before and after the linear solve. The former offers tighter coupling by enabling the linear solver to act directly on the face velocities of the staggered mesh, while the latter provides a sparser linear system and a simpler implementation. We demonstrate the effectiveness of our approach with animations of spatially varying viscosity, realistic rotational motion, and viscous liquid buckling and coiling
Tetrahedral Embedded Boundary Methods for Accurate and Flexible Adaptive Fluids
This is the peer reviewed version of the following article: Batty, C., Xenos, S., & Houston, B. (2010, May). Tetrahedral embedded boundary methods for accurate and flexible adaptive fluids. In Computer Graphics Forum (Vol. 29, No. 2, pp. 695-704). Oxford, UK: Blackwell Publishing Ltd., which has been published in final form at https://doi.org/10.1111/j.1467-8659.2009.01639.x. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.When simulating fluids, tetrahedral methods provide flexibility and ease of adaptivity that Cartesian grids find difficult to match. However, this approach has so far been limited by two conflicting requirements. First, accurate simulation requires quality Delaunay meshes and the use of circumcentric pressures. Second, meshes must align with potentially complex moving surfaces and boundaries, necessitating continuous remeshing. Unfortunately, sacrificing mesh quality in favour of speed yields inaccurate velocities and simulation artifacts. We describe how to eliminate the boundary‐matching constraint by adapting recent embedded boundary techniques to tetrahedra, so that neither air nor solid boundaries need to align with mesh geometry. This enables the use of high quality, arbitrarily graded, non‐conforming Delaunay meshes, which are simpler and faster to generate. Temporal coherence can also be exploited by reusing meshes over adjacent timesteps to further reduce meshing costs. Lastly, our free surface boundary condition eliminates the spurious currents that previous methods exhibited for slow or static scenarios. We provide several examples demonstrating that our efficient tetrahedral embedded boundary method can substantially increase the flexibility and accuracy of adaptive Eulerian fluid simulation
Bypassing the requirement for aminoacyl-tRNA by a cyclodipeptide synthase enzyme
C. J. H. and C. M. C. are funded by the Wellcome trust (210486/Z/18/Z), ES is funded by the Cunningham trust (PhD-CT-18-41).Cyclodipeptide synthases (CDPSs) produce a variety of cyclic dipeptide products by utilising two aminoacylated tRNA substrates. We sought to investigate the minimal requirements for substrate usage in this class of enzymes as the relationship between CDPSs and their substrates remains elusive. Here, we investigated the Bacillus thermoamylovorans enzyme, BtCDPS, which synthesises cyclo(L-Leu–L-Leu). We systematically tested where specificity arises and, in the process, uncovered small molecules (activated amino esters) that will suffice as substrates, although catalytically poor. We solved the structure of BtCDPS to 1.7 Å and combining crystallography, enzymatic assays and substrate docking experiments propose a model for how the minimal substrates interact with the enzyme. This work is the first report of a CDPS enzyme utilizing a molecule other than aa-tRNA as a substrate; providing insights into substrate requirements and setting the stage for the design of improved simpler substrates.Publisher PDFPeer reviewe
Allopurinol treatment adversely impacts left ventricular mass regression in patients with well-controlled hypertension
Development of a sensitive real-time quaking-induced conversion (RT-QuIC) assay for application in prion-infected blood.
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