562 research outputs found

    Magnetic Properties of a Two-Dimensional Mixed-Spin System

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    Using a Langmuir-Blodgett (LB) synthesis method, novel two-dimensional (2D) mixed-spin magnetic systems, in which each magnetic layer is both structurally and magnetically isolated, have been generated. Specifically, a 2D Fe-Ni cyanide-bridged network with a face-centered square grid structure has been magnetically and structurally characterized. The results indicate the presence of ferromagnetic exchange interactions between the Fe3+^{3+} (S=1/2S=1/2) and Ni2+^{2+} (S=1) centers.Comment: 2 pages, 3 figs., submitted 23rd International Conference on Low Temperature Physics (LT-23), Aug. 200

    Detergent Extraction of a Presumptive Gating Component from the Voltage-Dependent Sodium Channel

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    A physiologically characterized radiolabeled neurotoxin complex obtained from venom of the scorpion Leiurus quinquestriatus has been used to identify detergent-solubilized presumptive sodium channel components in sucrose gradients. This toxin-binding component is found in extracts prepared from three sources of excitable membrane but appears to be absent from similar extracts prepared from nonexcitable membrane or from Torpedo californica membrane. Procedures that destroy the physiological activity of the Leiurus neurotoxin lead to a corresponding loss of toxin binding to the putative sodium channel component. The major component recognized by the Leiurus toxin sediments at 6.5 S. Scatchard analysis of quantitative binding experiments carried out in sucrose gradients shows approximately linear plots and indicates that the toxin recognizes a relatively small number of sites with a dissociation constant near 10 nM. Once formed, the channel element--toxin complex is quite stable. Experiments show diphasic dissociation kinetics with half-times near 70 hr and greater than 200 hr

    Canine intrahepatic portosystemic shunt insertion into the systemic circulation is commonly through primary hepatic veins as assessed with CT angiography

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    Congenital intrahepatic portosystemic shunts (IHPSS) in dogs are traditionally classified as right, left, or central divisional. There are few descriptive studies regarding the variation of IHPSS within these categories. This multicenter, analytical, cross‐sectional study aimed to describe a large series of dogs with CT angiography (CTA) of IHPSS, hypothesizing that there would be variation to the existing classification. Ninety CTA studies were assessed for IHPSS type, insertion, and the relationship of the insertion to the primary hepatic veins. Ninety‐two percent of IHPSS inserted into a primary hepatic vein (HV) or phrenic vein, 8% inserted directly into the ventral aspect of the intrahepatic caudal vena cava. The most common IHPSS type was a single right divisional (44%), including those inserting via the right lateral HV or the caudate HV. Left divisional IHPSS (33%) inserted into the left HV or left phrenic vein. Central divisional IHPSS (13%) inserted into the quadrate HV, central HV, dorsal right medial HV, or directly into the ventral aspect of the intrahepatic caudal vena cava. Multiple sites of insertion were seen in 9% of dogs. Within left, central, and right divisional types, further subclassifications can therefore commonly be defined based on the hepatic veins with which the shunting vessel communicates. Relating IHPSS morphology to the receiving primary HV could make IHPSS categorization more consistent and may influence the type and method of IHPSS attenuation recommended

    Electronic Structure, Pore Size Distribution, and Sorption Characterization of an Unusual MOF, {[Ni(dpbz)][Ni(CN)\u3csub\u3e4\u3c/sub\u3e]}n, dpbz = 1,4-bis(4-pyridyl)benzene

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    The monoclinic (Ni(L)[Ni(CN)4] (L= 1,4-Bis(4-pyridyl) benzene) compound (defined as Ni-dpbz) is a flexible metal organic framework which assumes a pillared structure with layers defined by 2D Ni[Ni(CN)4]n nets and dpbz ligands as pillars. The structure features an entrapped dpbz ligand that links between the open ends of four-fold Ni sites from two neighboring chains. This arrangement results in an unusual 5-fold pseudo square-pyramid environment for Ni and a significantly long Ni-N distance of 2.369(4) Å. Using Density Functional Theory calculations, the different bonding characteristics between the 5-fold and 6-fold Ni\u27s were determined. We found that there is weak covalent bonding between the 5-fold Ni and N in the entrapped ligand, and the 6-fold Ni-N bonds provide effective electronic conduction. The disordered dimethyl sulfoxide (DMSO) solvent molecules are not bonded to the framework. The material has a single pore with a diameter of 4.1 Å. This pore includes approximately 55% of the total free volume (based on a zero-diameter probe). The accessible pore surface area and pore volume were calculated to be 507 m2/g and 6.99 cm3/kg, respectively. The maximum amount of CO2 that can be accommodated in the pores after DMSO is removed was found to be 204 mg/g, agreeing with the results of adsorption/desorption experiments of about 220 mg/g

    An Introduction to Texas Senate Bill 5

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    Four areas in Texas have been designated by the U.S. Environmental Protection Agency (EPA) as non-attainment areas because ozone levels exceed the National Ambient Air Quality Standards (NAAQS) maximum allowable limits: Beaumont-Port Arthur, El Paso, Dallas-Ft. Worth, and Houston-Galveston-Brazoria. The El Paso area also violates the NAAQS maximum allowable limits for carbon monoxide and respirable particulate matter. These areas face severe sanctions, such as loss of access to federal transportation funds, if attainment is not reached by 2007. Four additional areas in the state are also approaching national ozone limits, including: Austin, Corpus Christi, San Antonio, and the Longview-Tyler-Marshall area. Ozone is formed when oxides of nitrogen (NOx), volatile organic compounds (VOCs), and oxygen (O2) combine in the presence of strong sunlight. In response to this effort the Texas Natural Resource Conservation Commission (TNRCC) developed a strategy with the EPA that reduced VOCs from large regulated, stationary point sources by over 50 percent during the 1990 to 1996 period. Although this first strategy was very successful, levels of ozone failed to meet the national standards, and a second strategy had to be developed to achieve compliance with the ozone standard. In 2001, the Texas State Senate passed Senate Bill 5 (SB 5) to further reduce ozone levels by encouraging the reduction of emissions of NOx by sources that are currently not regulated by the TNRCC, including area sources (e.g., residential emissions), on-road mobile sources (e.g., all types of motor vehicles), and non-road mobile sources (e.g., aircraft, locomotives, etc.). This paper outlines the legislation, and responsibilities of the different government entities and the important role that private industry is being encouraged to play

    Texas' Senate Bill 5 Legislation for Reducing Pollution in Non-Attainment and Affected Areas: Procedures for Measuring Electricity Savings from the Adoption of the International Energy Conservation Code (IRC/IECC 2001) in New Residences

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    Four areas in Texas have been designated by the EPA as non-attainment areas because ozone levels exceed the NAAQS maximum allowable limits, Beaumont-Port Arthur, El Paso, Dallas-Ft. Worth, and Houston-Galveston-Brazoria. These areas face severe sanctions if attainment is not reached by 2007. Four additional areas in the state are also approaching national ozone limits (i.e., affected areas), including: Austin, Corpus Christi, San Antonio, and the Longview-Tyler-Marshall area. In 2001, the Texas State Legislature formulated and passed Senate Bill 5 to further reduce ozone levels by encouraging the reduction of emissions of NOx by sources that are currently not regulated by the TNRCC, including area sources (e.g., residential emissions), on-road mobile sources (e.g., all types of motor vehicles), and non-road mobile sources (e.g., aircraft, locomotives, etc.). An important part of this legislation is the evaluation of the State's energy efficiency programs, which includes reductions in energy use and demand that are associated with specific energy conservation measures. This paper outlines the procedures that are being developed to report the electricity savings associated with the adoption of the International Energy Conservation Code (IECC 2001) in residential construction in non-attainment and affected counties. These electricity savings will then be converted to NOx reductions using the appropriat

    Texas’ Senate Bill 5 Legislation for Reducing Pollution in Non-Attainment and Affected Areas: Annual Report to the Texas Natural Resource Conservation Commission

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    This is the first annual report by the Energy Systems Laboratory, which covers the Laboratory's efforts to support Senate Bill 5. In this report the accomplishments and progress to date are presented, along with recommendations, issues encountered to date and what is needed to fulfill the Laboratory's responsibilities. A section of this report also discusses the technology of reporting and verifying emissions reductions from the energy used in buildings, and presents an overview of the technologies for reducing energy use in buildings. Preliminary findings are also presented regarding the estimation of NOx reduction from several building-related energy conservation measures, and recommendations are provided regarding improvements to the NOx accounting methods

    Texas’ Senate Bill 5 Legislation for Reducing Pollution in Non-Attainment and Affected Areas: Report for the TERP Advisory Board Meeting

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    This report outlines the Energy Systems Laboratory's responsibilities in Senate Bill 5, accomplishments to date, recommendations to the TERP Advisory Group, and problems encountered to date and what is needed to fulfill the Laboratory's responsibilities. A section of this report also discusses the technology of reporting and verifying emissions reductions from the energy used in buildings, and presents an overview of the technologies for reducing energy use in buildings

    Energy Efficiency/Renewable Energy Impact in the Texas Emissions Reduction Plan (TERP), Volume II – Technical Report, Annual Report to the Texas Commission on Environmental Quality September 2002 – August 2003

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    The Texas Emissions Reduction Plan (TERP), established by the 77th Texas Legislature with the enactment of Senate Bill 5 (SB 5), states that energy efficiency and renewable energy (EE/RE) measures are needed to meet the minimum federal air quality standards. The 78th Legislature further enhanced the use of EE/RE programs for meeting TERP goals by requiring the Texas Council on Environmental Quality (TCEQ) to promote the use of energy efficiency as a way of meeting the federal air quality standards and to develop a methodology for computing emissions reduction for the SIP from energy efficiency.The report appendicies are contained in Volume III which is not published online. The files can be downloaded upon request by contacting [email protected] Energy Systems Laboratory (Laboratory) is pleased to provide our second annual report, Energy Efficiency/Renewable Energy Impact in the Texas Emissions Reduction Plan to the Texas Council on Environmental Quality (TCEQ) in fulfillment of its responsibilities under Texas Health and Safety Code Ann. § 388.003, (e) (a) (b) (Vernon Supp. 2002). This annual report: provides an estimate of the energy savings and NOx reductions from energy code compliance in new residential construction in 38 counties, describes the technology developed to enable the TCEQ to substantiate energy and emissions reduction credits from EE/RE to the Environmental Protection Agency (EPA), and provides valuable insights into the effectiveness of additional energy efficiency and renewable energy measures in existing buildings and industrial facilities
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