985 research outputs found

    A Polynomial Spectral Calculus for Analysis of DG Spectral Element Methods

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    We introduce a polynomial spectral calculus that follows from the summation by parts property of the Legendre-Gauss-Lobatto quadrature. We use the calculus to simplify the analysis of two multidimensional discontinuous Galerkin spectral element approximations

    R&D ERL: Diagnostics

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    The Energy Recovery Linac (ERL) prototype project is currently under development at the Brookhaven National Laboratory. The ERL is expected to demonstrate energy recovery of high intensity beams with a current of up to a few hundred milliamps, while preserving the emittance of bunches with a charge of a few nanocoulombs produced by a high current SRF gun. To successfully accomplish this task the machine will include beam diagnostics that will be used for accurate characterization of the three dimensional beam phase space at the injection and recirculation energies, transverse and longitudinal beam matching, orbit alignment, beam current measurement, and machine protection. This report outlines requirements on the ERL diagnostics and describes its setup and modes of operation. The BNL Prototype ERL is an R&D effort aimed at reducing risks and costs associated with the proposed RHIC II electron cooler and eRHIC collider. The ERL will serve as a test bed for developing and testing instrumentation and studying physics and technological issues relevant to very high current ERL's. The prototype ERL, mated to a high current SRF gun, is expected to demonstrate production and energy recovery of high intensity, low emittance beams with a current of up to a few hundred milliamps. To successfully accomplish this task the ERL will include beam diagnostics required to characterize and tune beam parameters, as well as for machine protection. A preliminary diagnostics plan was presented in earlier publications. In this report, we describe the diagnostics presently planned to provide the data needed to meet these goals

    UC-82 Trip Logger

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    We developed an Android mobile app using the Software Development Life Cycle (SDLC) approach to enable users to track their travel distance and time via GPS, fostering greater emissions awareness through their driving habits of distance and time taken. Built with the Flutter framework and Dart language, the app features a user-friendly interface created with Flutter widgets that manage both appearance and user interactions. Our streamlined architecture comprises three layers: the presentation layer for UI elements, the application layer containing the core logic, and the data layer, which locally stores trip data in CSV format to ensure quick access and reliability. We integrated the Geolocator package within Flutter for GPS functionality to obtain user coordinates and calculate distances between locations. This streamlined architecture and choice of technologies optimized the app’s efficiency and user-friendliness, allowing us to promote environmentally conscious driving

    Combined Collection and Analysis of Inorganic and Organic Gunshot Residues.

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    Gunshot residue (GSR) analysis and their interpretation provide crucial information on a criminal investigation involving the use of firearms. To date, several approaches have been proposed for the implementation of a combined sampling and analysis of inorganic (IGSR) and organic GSR (OGSR). However, it is not clear at this stage if concurrent analyses of both types of residue might be detrimental to the analysis of IGSR currently applied in forensic laboratories. Thus, this work aims to compare and evaluate three different protocols for the combined collection and analysis of IGSR and OGSR. These methods, respectively, involve the use of a modified stub (with two halves, one for the detection of IGSR and the other for the analysis of OGSR); the sequential recovery of GSR with two stubs mounted with different adhesives (double-sided carbon tape and Tesa® TACK) and the sequential analysis of IGSR and OGSR from a single carbon stub following carbon deposition. The detection of IGSR was carried out using SEM-EDX, while OGSR analysis was performed using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Obtained results for experiments performed using Geco Sinoxid <sup>®</sup> ammunition indicated that sequential analysis was the most suitable protocol for the combined collection and analysis of both IGSR and OGSR. A higher number of inorganic (characteristic and consistent) particles and higher concentrations of ethylcentralite, N-nitrosodiphenylamine, diphenylamine, and nitroglycerin were recovered with this method

    Secondary transfer of organic gunshot residues: Empirical data to assist the evaluation of three scenarios.

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    The present study aimed at providing data to assess the secondary transfer of organic gunshot residues (OGSR). Three scenarios were evaluated in controlled conditions, namely displacing a firearm from point A to point B, a simple handshake and an arrest involving handcuffing on the ground. Specimens were collected from the firearm, the hands of the shooter and the non-shooter undergoing the secondary transfer in order to compare the amounts detected. Secondary transfer was observed for the three scenarios, but to a different extent. It was found that displacing a firearm resulted in secondary transfer in <50% of the experiments. The firearm also had an influence, as contrary to the pistol, no secondary OGSR were detected using the revolver. Shaking the hand of the shooter also transferred OGSR to the non-shooter's hand. In that case, the amount of OGSR was generally higher on the shooter than on the non-shooter. Finally, the largest secondary transfer was observed after the arrest with handcuffing with positive results in all cases using the pistol. In that scenario, the amounts on the shooter and the non-shooter were in the same range. This study highlights that the secondary transfer must be taken into account in the interpretation of OGSR. Indeed, an individual's hands might be contaminated by handling a firearm or having physical contact with a shooter

    Performance management from the bottom up

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    Current interest in middle-managers’ compliance with performance management (PM) reforms focuses on their downward roles. To explore their understudied upward roles, this analysis draws on police chiefs’ voice directed to senior management regarding the Israeli PM system as documented since its first introduction in 1999, and as reported both by chiefs and senior managers (N = 54). Unfolding four patterns of inconsistencies between PM systems’ design and the operational, daily, course-of-work, close-to-the-field managers’ upward roles allows us to move beyond criticism to constructive efforts, and provides new insights for reconciling the well-documented gap between policy intentions and outcomes in PM reforms.The politics and administration of institutional chang

    Fast readout algorithm for cylindrical beam position monitors providing good accuracy for particle bunches with large offsets

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    A simple, analytically correct algorithm is developed for calculating pencil beam coordinates using the signals from an ideal cylindrical particle beam position monitor (BPM) with four pickup electrodes (PUEs) of infinitesimal widths. The algorithm is then applied to simulations of realistic BPMs with finite width PUEs. Surprisingly small deviations are found. Simple empirically determined correction terms reduce the deviations even further. The algorithm is then used to study the impact of beam-size upon the precision of BPMs in the non-linear region. As an example of the data acquisition speed advantage, a FPGA-based BPM readout implementation of the new algorithm has been developed and characterized. Finally,the algorithm is tested with BPM data from the Cornell Preinjector.Comment: 21 pages, 17 figure

    Freshwater Ecosystems: From Models to Applications

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    Freshwater ecosystems—lakes and streams—are being endangered by agricultural, urban, and industrial pollution; hydraulic engineering; and overexploitation, which threaten their capacity to provide important services (recreation and supply of food and clean water, among others). Ecological modeling may be employed to estimate impacts and analyze mitigation strategies. Toy models are easy to construct, but applying them to real-world problems is often challenging. Here, we show in two case studies how the connection from model to application can be made. The first study analyzes whether and how the impact of climatic change on a mostly recreational fishery in an Alpine lake can be mitigated, while the second looks at restoring biodiversity after cleaning up pollution in a Korean river system, using aquatic insects, which play an essential functional role in aquatic food-webs and are very sensitive to water quality, as indicators of ecosystem health. These studies highlight the ability of process-based eco-evolutionary models to generate testable hypotheses and contribute solutions to real-world problems
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