2,315 research outputs found

    Performance of Vegetative Filters Considering Conservation Practices, Field Slope, and Storm Characteristics

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    Vegetative filter systems are being used nationwide as a management practice for controlling sediment delivery to water bodies, especially in agricultural settings. The installation of vegetative filter systems has increased in agricultural areas in part because of the National Conservation Buffer Initiative implemented by the USDA Natural Resources Conservation Service. Vegetative filters have the effect of retarding the velocity and reducing the sediment transport capacity of water flow (Tollner et al., 1982). As a result, a portion of the sediment in the water flowing through the filter will be deposited thus decreasing the movement of sediment to water bodies

    Safe handling of potential peroxide forming compounds and their corresponding peroxide yielded derivatives.

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    This report addresses recent developments concerning the identification and handling of potential peroxide forming (PPF) and peroxide yielded derivative (PYD) chemicals. PPF chemicals are described in terms of labeling, shelf lives, and safe handling requirements as required at SNL. The general peroxide chemistry concerning formation, prevention, and identification is cursorily presented to give some perspective to the generation of peroxides. The procedure for determining peroxide concentrations and the proper disposal methods established by the Hazardous Waste Handling Facility are also provided. Techniques such as neutralization and dilution are provided for the safe handling of any PYD chemicals to allow for safe handling. The appendices are a collection of all available SNL documentation pertaining to PPF/PYD chemicals to serve as a single reference

    Bifurcated polarization rotation in bismuth-based piezoelectrics

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    ABO3 perovskite-type solid solutions display a large variety of structural and physical properties, which can be tuned by chemical composition or external parameters such as temperature, pressure, strain, electric, or magnetic fields. Some solid solutions show remarkably enhanced physical properties including colossal magnetoresistance or giant piezoelectricity. It has been recognized that structural distortions, competing on the local level, are key to understanding and tuning these remarkable properties, yet, it remains a challenge to experimentally observe such local structural details. Here, from neutron pair-distribution analysis, a temperature-dependent 3D atomic-level model of the lead-free piezoelectric perovskite Na0.5Bi0.5TiO3 (NBT) is reported. The statistical analysis of this model shows how local distortions compete, how this competition develops with temperature, and, in particular, how different polar displacements of Bi3+ cations coexist as a bifurcated polarization, highlighting the interest of Bi-based materials in the search for new lead-free piezoelectrics

    Readily accessible sp3-rich cyclic hydrazine frameworks exploiting nitrogen fluxionality

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    Increased molecular complexity correlates with improved chances of success in the drug development process. Here, a strategy for the creation of sp3-rich, non-planar heterocyclic scaffolds suitable for drug discovery is described that obviates the need to generate multiple stereogenic centers with independent control. Asymmetric transfer hydrogenation using a tethered Ru-catalyst is used to efficiently produce a range of enantiopure cyclic hydrazine building blocks (up to 99% ee). Iterative C–N functionalization at the two nitrogen atoms of these compounds produces novel hydrazine and hydrazide based chemical libraries. Wide chemical diversification is possible through variation in the hydrazine structure, use of different functionalization chemistries and coupling partners, and controlled engagement of each nitrogen of the hydrazine in turn. Principal Moment of Inertia (PMI) analysis of this small hydrazine library reveals excellent shape diversity and three-dimensionality. NMR and crystallographic studies confirm these frameworks prefer to orient their substituents in three-dimensional space under the control of a single stereogenic center through exploitation of the fluxional behavior of the two nitrogen atoms

    Data Mining and Privacy: An Initial Attempt at a Comprehensive Code of Conduct for Online Business

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    The prevalence of data mining by businesses and government organizations raises concerns among many individuals about the privacy of their personal data. We address this issue by offering a different perspective that reconciles the conflicting desires of businesses and consumers. We describe privacy, data mining, and their interaction in the larger context, identify the costs and benefits of the uses of data mining, and discuss potential stakeholders found at the intersection of the two subjects. To help synthesize our proposed code of ethical conduct, we examine existing codes of conduct and how they relate to the issue of privacy in the context of data mining with people, processes, and technology. Showing that a uniform code of ethical conduct for online privacy is feasible from both a managerial and ethical perspective, we provide an initial philosophical and principle synthesis that businesses and organizations can tailor for their own specific customers and needs. The developed code of ethical conduct respects consumers’ desire for privacy while allowing businesses to use data mining techniques to elicit information that benefits both the business and the consumer
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