1,346 research outputs found

    Numerical Method for Shock Front Hugoniot States

    Full text link
    We describe a Continuous Hugoniot Method for the efficient simulation of shock wave fronts. This approach achieves significantly improved efficiency when the generation of a tightly spaced collection of individual steady-state shock front states is desired, and allows for the study of shocks as a function of a continuous shock strength parameter, vpv_p. This is, to our knowledge, the first attempt to map the Hugoniot continuously. We apply the method to shock waves in Lennard-Jonesium along the direction. We obtain very good agreement with prior simulations, as well as our own benchmark comparison runs.Comment: 4 pages, 3 figures, from Shock Compression of Condensed Matter 200

    PUBLIC UTILITIES AND PUBLIC TRANSPORTATION Distribution, Storage and Sale of Gas: Amend the Natural Gas Competition and Deregulation Act ; Provide That a Retail Customer May Change Marketers Once a Year Without Penalty; Limit the Amount of Deposit; Provide for Deposit Refunds; Require Certain Disclosures by the Public Service Commission; Authorize Said Commission to Regulate the Gas Market Under Certain Conditions; Regulate Marketer Billing Practices; Change the Provisions of the Universal Service Fund

    Get PDF
    The Act amends the Natural Gas Competition and Deregulation Act of 1997 by codifying several consumer protection measures. The Act permits consumers to change marketers once a year without incurring a service fee, and it limits the deposit amount a marketer may charge. The Act sets forth criteria for determining when the gas market is not competitive and when the Public Service Commission may regulate an uncompetitive market. The Act regulates marketer billing practices and requires marketers to publish certain information related to their billing practices. The Act also mandates that the universal service fund be used primarily to assist low-income customers in times of emergency and hardship

    Coating thickness and coverage effects on the forces between silica nanoparticles in water

    Full text link
    The structure and interactions of coated silica nanoparticles have been studied in water using molecular dynamics simulations. For 5 nm diameter amorphous silica nanoparticles we studied the effects of varying the chain length and grafting density of polyethylene oxide (PEO) on the nanoparticle coating's shape and on nanoparticle-nanoparticle effective forces. For short ligands of length n=6n=6 and n=20n=20 repeat units, the coatings are radially symmetric while for longer chains (n=100n=100) the coatings are highly anisotropic. This anisotropy appears to be governed primarily by chain length, with coverage playing a secondary role. For the largest chain lengths considered, the strongly anisotropic shape makes fitting to a simple radial force model impossible. For shorter ligands, where the coatings are isotropic, we found that the force between pairs of nanoparticles is purely repulsive and can be fit to the form (R/2rcore−1)−b(R/2r_\text{core}-1)^{-b} where RR is the separation between the center of the nanoparticles, rcorer_\text{core} is the radius of the silica core, and bb is measured to be between 2.3 and 4.1.Comment: 20 pages, 6 figure

    Searching for Dark Photons with Maverick Top Partners

    Full text link
    In this paper, we present a model in which an up-type vector-like quark (VLQ) is charged under a new U(1)dU(1)_d gauge force which kinetically mixes with the SM hypercharge. The gauge boson of the U(1)dU(1)_d is the dark photon, γd\gamma_d. Traditional searches for VLQs rely on decays into Standard Model electroweak bosons W,ZW,Z or Higgs. However, since no evidence for VLQs has been found at the Large Hadron Collider (LHC), it is imperative to search for other novel signatures of VLQs beyond their traditional decays. As we will show, if the dark photon is much less massive than the Standard Model electroweak sector, Mγd≪MZM_{\gamma_d}\ll M_Z, for the large majority of the allowed parameter space the VLQ predominately decays into the dark photon and the dark Higgs that breaks the U(1)dU(1)_d . That is, this VLQ is a `maverick top partner' with nontraditional decays. One of the appeals of this scenario is that pair production of the VLQ at the LHC occurs through the strong force and the rate is determined by the gauge structure. Hence, the production of the dark photon at the LHC only depends on the strong force and is largely independent of the small kinetic mixing with hypercharge. This scenario provides a robust framework to search for a light dark sector via searches for heavy colored particles at the LHC.Comment: 40 pages and 11 figure

    Forces between functionalized silica nanoparticles in solution

    Full text link
    To prevent the flocculation and phase separation of nanoparticles in solution, nanoparticles are often functionalized with short chain surfactants. Here we present fully-atomistic molecular dynamics simulations which characterize how these functional coatings affect the interactions between nanoparticles and with the surrounding solvent. For 5 nm diameter silica nanoparticles coated with poly(ethylene oxide) (PEO) oligomers in water, we determined the hydrodynamic drag on two approaching nanoparticles moving through solvent and on a single nanoparticle as it approaches a planar surface. In most circumstances, acroscale fluid theory accurately predicts the drag on these nano-scale particles. Good agreement is seen with Brenner's analytical solutions for wall separations larger than the soft nanoparticle radius. For two approaching coated nanoparticles, the solvent-mediated (velocity-independent) and lubrication (velocity-dependent) forces are purely repulsive and do not exhibit force oscillations that are typical of uncoated rigid spheres.Comment: 4 pages, 3 fig

    Simulations of the temporal and spatial resolution for a compact time-resolved electron diffractometer

    Get PDF
    A novel compact electron gun for use in time-resolved gas electron diffraction experiments has recently been designed and commissioned. In this paper we present and discuss the extensive simulations that were performed to underpin the design in terms of the spatial and temporal qualities of the pulsed electron beam created by the ionisation of a gold photocathode using a femtosecond laser. The response of the electron pulses to a solenoid lens used to focus the electron beam has also been studied. The simulated results show that focussing the electron beam affects the overall spatial and temporal resolution of the experiment in a variety of ways, and that factors that improve the resolution of one parameter can often have a negative effect on the other. A balance must, therefore, be achieved between spatial and temporal resolution. The optimal experimental time resolution for the apparatus is predicted to be 416 fs for studies of gas-phase species, while the predicted spatial resolution of better than 2 nm-1 compares well with traditional time-averaged electron diffraction set-ups

    Heat-dried sclerotia of Sclerotinia sclerotiorum myceliogenically germinate in water and are able to infect Brassica napus

    Get PDF
    The phytopathogenic fungus Sclerotinia sclerotiorum forms dormant structures (termed sclerotia) that germinate myceliogenically under certain environmental conditions. During myceliogenic germination, sclerotia produce hyphae, which can infect leaves or stems of host plants directly from the ground; this is termed basal infection. This study determined which abiotic conditions were most important for promoting myceliogenic germination of sclerotia in vitro. A high sclerotium hydration level and low incubation temperature (158C) improved mycelial growth in the presence of a nutrient source. Sclerotia incubated without a nutrient source on moist sand, vigorously myceliogenically germinated most frequently (63%) when they had been previously imbibed and then conditioned at -20°C. By far the most consistent amount of vigorous myceliogenic germination (>75%) was produced when sclerotia were heat-dried before being submerged in water. The hyphae of these sclerotia were shown to infect and proliferate on leaves of intact Brassica napus plants. This research provides a better understanding of the abiotic conditions that are likely to increase the risk of basal infection by S. sclerotiorum

    Quantifying Forest Ground Flora Biomass Using Proximal Sensing

    Get PDF
    Current focus on forest conservation and forest sustainability has increased the level of attention given to measures of ground flora in forest ecosystems. Traditionally, such data are collected via time- and resource-intensive methods of field identification, clipping, and weighing. With increased focus on community composition and structure measures of forest ground flora, the manner in which these data are collected must change. This project uses color and color infrared digital cameras to proximally sense forest ground flora and to develop regression models to predict green and dry biomass (g/m^) from the proximally sensed data. Traditional vegetative indices such as the Normalized Difference Vegetative Index (NDVI) and the Average Visible Reflectance Index (AVR) explained 35-45% of the variation in forest ground flora biomass. Adding individual color band variables, especially the red and near infrared bands, to the regression model allowed the model to explain 66% and 58% of the variation in green and dry biomass, respectively, present

    Religious but not ethical: The effects of extrinsic religiosity, ethnocentrism and self-righteousness on consumers' ethical judgements

    Get PDF
    The current research investigates how religiosity can influence unethicality in a consumption context. In particular, considering the link between extrinsic religious orientations and unethicality, this research clarifies why and when extrinsic religiosity leads to unethical decisions. Across two studies, findings show that ethnocentrism is both a mediator (Study 1) and a moderator (Studies 1 and 2) of the effects of extrinsic religiosity on consumers’ ethical judgments. This is because extrinsic religiosity leads to ethnocentrism, and in-group loyalty manifested through ethnocentrism increases support for unethical consumer actions, thus establishing ethnocentrism as a mediator. At the same time, different levels of ethnocentrism can also influence how extrinsic religiosity leads to supporting unethical consumption via self-righteousness, thus establishing ethnocentrism as a moderator. The findings from this research have significant implications for diverse stakeholders who have an interest in religiosity and consumer behavior

    Challenge and Hold One Another Accountable: Social Work Faculty Respond to Incivility

    Get PDF
    Incivility within social work education reflects patterns seen across higher education and within society. Previous work has found that social work faculty are reluctant to report incivility and have limited confidence in their ability to address it effectively. In order to address potential solutions, this paper uses qualitative data (n = 164) drawn from a larger survey of social work faculty in the United States. The exploratory analysis focuses on strategies social work faculty use when experiencing incivility and bullying them-selves, and methods recommended by social work faculty to confront incivility administratively and systemically within the social work academy. Responses were coded into four themes: values-based responses, leadership/ institutional responses, individual and faculty level responses, and faculty disengagement. These themes suggest opportunities and recommendations to move toward a civil social work academy
    • …
    corecore