1,075 research outputs found

    Fabrication of Atomically Precise Nanopores in Hexagonal Boron Nitride

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    We demonstrate the fabrication of individual nanopores in hexagonal boron nitride (hBN) with atomically precise control of the pore size. Previous methods of pore production in other 2D materials create pores of irregular geometry with imprecise diameters. By taking advantage of the preferential growth of boron vacancies in hBN under electron beam irradiation, we are able to observe the pore growth via transmission electron microscopy, and terminate the process when the pore has reached its desired size. Careful control of beam conditions allows us to nucleate and grow individual triangular and hexagonal pores with diameters ranging from subnanometer to 6nm over a large area of suspended hBN using a conventional TEM. These nanopores could find application in molecular sensing, DNA sequencing, water desalination, and molecular separation. Furthermore, the chemical edge-groups along the hBN pores can be made entirely nitrogen terminated or faceted with boron-terminated edges, opening avenues for tailored functionalization and extending the applications of these hBN nanopores.Comment: 5 pages, 6 figure

    Intracranial fusarium fungal abscess in an immunocompetent patient: case report and review of the literature.

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    Introductionā€ƒFusarium spp is an omnipresent fungal species that may lead to fatal infections in immunocompromised populations. Spontaneous intracranial infection by Fusarium spp in immunocompetent individuals is exceedingly rare. Case Reportā€ƒAn immunocompetent 33-year-old Hispanic woman presented with persistent headaches and was found to have a contrast-enhancing mass in the left petrous apex and prepontine cistern. She underwent a subsequent craniotomy for biopsy and partial resection that revealed a Fusarium abscess. She had a left transient partial oculomotor palsy following the operation that resolved over the next few weeks. She was treated with long-term intravenous antifungal therapy and remained at her neurologic baseline 18 months following the intervention. Discussionā€ƒTo our knowledge, this is the first reported case of Fusarium spp brain abscess in an immunocompetent patient. Treatment options include surgical intervention and various antifungal medications. Conclusionā€ƒThis case demonstrates the rare potential of intracranial Fusarium infection in the immunocompetent host, as well as its successful treatment with surgical aspiration and antifungal therapy

    Constructing Client-Server Multi-Player Asynchronous Networked Games Using a Single-Computer Model

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    We examine the process of creating asynchronous networked games by applying systematic transformations to their single-computer analogues, identify the need for such transformations, and propose a simple system of rules for them. In developing these rules, our primary concerns are comparing the flow of events in single-processor and networked games and examining the restrictions and limitations resulting from speed considerations. Although this paper only discusses games, the transformation rides may apply to any networked application with asynchronous data input and exchange

    Emergency Egress for People with Mobility Impairments in Australia

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    Most people will have a disability, temporary or permanent, at some point in their life; Australian building regulations do not provide equitable means of egress for them. The goal of this project was to investigate how emergency egress codes for people with mobility impairments can be implemented in building regulations. Through interviews and intensive research it was determined that provisions such as areas of refuge and lifts should be included in the Building Code of Australia as a means to mitigate the risk of death

    Earth's Correlation Wavefield: Late Coda Correlation

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    Cross correlation of seismograms provides new information on the Earth both through the exploitation of ambient noise and specific components of earthquake records. Here we crossā€correlate recordings of large earthquakes on a planetary scale and identify a range of hitherto unobserved seismic phases in Earth's correlation wavefield. We show that both arrivals with the timing expected for the regular seismic wavefield and previously unexplained phases are produced by interference between seismic paths having the same ray parameter but with only a subset of propagation legs in common. This insight explains the origin and generation mechanism of the features of Earth's correlation wavefield and opens up new ways of addressing issues in global seismology. Strong similarity between observed and synthesized correlation wavefields indicates that the Earth's radial structure is remarkably well constrained in the intermediate period range

    Design of new cold rolled purlins by experimental testing and Direct Strength Method

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    New cold roll formed channel and zed sections for purlins, namely UltraBEAMā„¢2 and UltraZEDā„¢2, have been developed by Hadley Industries plc using a combined approach of experimental testing, finite element modelling and optimisation techniques. The new sections have improved strength to weight ratio by increasing the section's strength through the use of stiffeners in the section webs. The European standard, Eurocode 3 [1], uses the traditional Effective Width Method to determine the strength of a cold formed steel member. However, the design of the new sections UltraBEAMā„¢2 and UltraZEDā„¢2 using this method is very complicated in calculating the effective section properties as these sections contain complex folded-in stiffeners. In addition, the incorporation of competing buckling modes such as distortional buckling of these sections can be difficult to analyse. To overcome difficulties of using Eurocode 3 or such a standard with the Effective Width Method for determining the strength of these sections, the Direct Strength Method is adopted in this paper. Four-point beam bending tests were carried out to determine the buckling and ultimate bending capacities of the UltraBEAMā„¢2 and UltraZEDā„¢2 sections. Results from both experimental testing and Finite Element analysis were initially used as validation for the design using the Direct Strength Method. The Direct Strength Method's results were then compared with the experimental test results for a broader data in which the UltraBEAMā„¢2 and UltraZEDā„¢2 sections had a range of different width-to-thickness ratios. It showed an excellent agreement between test and Direct Strength design values suggesting that the Direct Strength Method is a powerful tool for the design and optimisation of the new cold roll formed channel and zed purlins.N/
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