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Sample records for hfb2 anf hfc

  1. Functional analysis of the class II hydrophobin gene HFB2-6 from the biocontrol agent Trichoderma asperellum ACCC30536.

    Science.gov (United States)

    Huang, Ying; Mijiti, Gulijimila; Wang, Zhiying; Yu, Wenjing; Fan, Haijuan; Zhang, Rongshu; Liu, Zhihua

    2015-02-01

    A class II hydrophobin gene, HFB2-6, was cloned from Trichoderma asperellum ACCC30536 and its biocontrol function was studied. According to our previous transcriptome data, six of the eight class II hydrophobin genes were obviously differential expression in four inducing conditions, especially the gene HFB2-6. Moreover, HFB2-6 proven to be differentially transcribed under eight different treatments. HFB2-6 transcripts were up-regulated under 1% Alternaria alternata cell wall and 5% A. alternata fermentation liquid treatments, and by nutritional stress conditions, suggesting that HFB2-6 plays roles in interactions with both biotic and abiotic environmental conditions. HFB2-6 expression was down-regulated under 1% poplar leaf powder culture conditions, but its expression was up-regulated under 1% poplar root powder, indicating that HFB2-6 has a function in root colonization. Furthermore, the recombinant hydrophobin rHFB2-6 was successfully expressed in Escherichia coli BL21-HFB2-6 and purified from the recombinant strain. Genes related to both the jasmonic acid and salicylic acid signal transduction pathways were up-regulated by interaction with renatured rHFB2-6. The ORCA3 (octadecanoid-derivative responsive Catharanthus AP2-domain) gene of the poplar jasmonic acid signal transduction pathway showed a peak expression of 4.48 times at 2 h, and the peak expression of PR1 (pathogenesis-related protein gene) in the salicylic acid signal transduction pathway was 4.58 times at 72 h. Two genes, MP (monopteros) and GH3.17 (auxin original response gene), in the auxin signal transduction pathway were also up-regulated after induction with rHFB2-6, indicating that rHFB2-6 can promote poplar growth and confer broad-spectrum resistance to pathogens.

  2. Lattice Thermal Conductivity from Atomistic Simulations: ZrB2 and HfB2

    Science.gov (United States)

    Lawson, John W.; Daw, Murray S.; Bauschlicher, Charles W.

    2012-01-01

    Ultra high temperature ceramics (UHTC) including ZrB2 and HfB2 have a number of properties that make them attractive for applications in extreme environments. One such property is their high thermal conductivity. Computational modeling of these materials will facilitate understanding of fundamental mechanisms, elucidate structure-property relationships, and ultimately accelerate the materials design cycle. Progress in computational modeling of UHTCs however has been limited in part due to the absence of suitable interatomic potentials. Recently, we developed Tersoff style parameterizations of such potentials for both ZrB2 and HfB2 appropriate for atomistic simulations. As an application, Green-Kubo molecular dynamics simulations were performed to evaluate the lattice thermal conductivity for single crystals of ZrB2 and HfB2. The atomic mass difference in these binary compounds leads to oscillations in the time correlation function of the heat current, in contrast to the more typical monotonic decay seen in monoatomic materials such as Silicon, for example. Results at room temperature and at elevated temperatures will be reported.

  3. Doping-induced superconductivity of ZrB2 and HfB2

    Science.gov (United States)

    Barbero, N.; Shiroka, T.; Delley, B.; Grant, T.; Machado, A. Â. J. Â. S.; Fisk, Z.; Ott, H.-R.; Mesot, J.

    2017-03-01

    Unlike the widely studied s -type two-gap superconductor MgB2, the chemically similar compounds ZrB2 and HfB2 do not superconduct above 1 K. Yet it has been shown that small amounts of self or extrinsic doping (in particular with vanadium), can induce superconductivity in these materials. Based on results of different macroscopic and microscopic measurements, including magnetometry, nuclear magnetic resonance (NMR), resistivity, and muon-spin rotation (μ+SR ), we present a comparative study of Zr0.96V0.04B2 and Hf0.97V0.03B2 . Their key magnetic and superconducting features are determined and the results are considered within the theoretical framework of multiband superconductivity proposed for MgB2. Detailed Fermi surface (FS) and electronic structure calculations reveal the difference between MgB2 and transition-metal diborides.

  4. Lattice Thermal Conductivity of Ultra High Temperature Ceramics ZrB2 and HfB2 from Atomistic Simulations

    Science.gov (United States)

    Lawson, John W.; Murray, Daw S.; Bauschlicher, Charles W., Jr.

    2011-01-01

    Atomistic Green-Kubo simulations are performed to evaluate the lattice thermal conductivity for single crystals of the ultra high temperature ceramics ZrB2 and HfB2 for a range of temperatures. Recently developed interatomic potentials are used for these simulations. Heat current correlation functions show rapid oscillations which can be identified with mixed metal-Boron optical phonon modes. Agreement with available experimental data is good.

  5. Role of WC additive on reaction, solid-solution and densification in HfB2–SiC ceramics

    DEFF Research Database (Denmark)

    Hu, Dong-Li; Zheng, Qiang; Gu, Hui

    2014-01-01

    A comparative study of phase components and compositions was performed for the pressureless sintered HfB2–SiC–WC composites by various analytical methods. The relative decrease of HfB2 phase leads to a new reaction of HfO2 removal by WC to create B2O3. By using SiC instead of Si3N4 as milling med...

  6. Phase and Microstructural Correlation of Spark Plasma Sintered HfB2-ZrB2 Based Ultra-High Temperature Ceramic Composites

    Directory of Open Access Journals (Sweden)

    Ambreen Nisar

    2017-07-01

    Full Text Available The refractory diborides (HfB2 and ZrB2 are considered as promising ultra-high temperature ceramic (UHTCs where low damage tolerance limits their application for the thermal protection system in re-entry vehicles. In this regard, SiC and CNT have been synergistically added as the sintering aids and toughening agents in the spark plasma sintered (SPS HfB2-ZrB2 system. Herein, a novel equimolar composition of HfB2 and ZrB2 has shown to form a solid-solution which then allows compositional tailoring of mechanical properties (such as hardness, elastic modulus, and fracture toughness. The hardness of the processed composite is higher than the individual phase hardness up to 1.5 times, insinuating the synergy of SiC and CNT reinforcement in HfB2-ZrB2 composites. The enhanced fracture toughness of CNT reinforced composite (up to a 196% increment surpassing that of the parent materials (ZrB2/HfB2-SiC is attributed to the synergy of solid solution formation and enhanced densification (~99.5%. In addition, the reduction in the analytically quantified interfacial residual tensile stress with SiC and CNT reinforcements contribute to the enhancement in the fracture toughness of HfB2-ZrB2-SiC-CNT composites, mandatory for aerospace applications.

  7. Lattice Thermal Conductivity of Ultra High Temperature Ceramics (UHTC) ZrB2 and HfB2 from Atomistic Simulations

    Science.gov (United States)

    Lawson, JOhn W.; Daw, Murray S.; Bauschlicher, Charles W.

    2011-01-01

    Ultra high temperature ceramics (UHTC) including ZrB2 and HfB2 are candidate materials for applications in extreme environments because of their high melting point, good mechanical properties and reasonable oxidation resistance. Unlike many ceramics, these materials have high thermal conductivity which can be advantageous, for example, to reduce thermal shock. Recently, we developed Tersoff style interatomic potentials for both ZrB2 and HfB2 appropriate for atomistic simulations. As an application, Green-Kubo molecular dynamics simulations were performed to evaluate the lattice thermal conductivity for single crystals of ZrB2 and HfB2. The atomic mass difference in these binary compounds leads to oscillations in the time correlation function of the heat current. Results at room temperature and at elevated temperatures will be reported.

  8. Taguchi Analysis on the Effect of Process Parameters on Densification During Spark Plasma Sintering of HfB2-20SiC (Preprint)

    Science.gov (United States)

    2011-11-01

    pressing and spark plasma sintering. J Alloys Compd 2007; 428:197–05. 2. Van Wie D.M., Drewry Jr. D.G., King D.E., Hudson C.M. The hypersonic environment...spark plasma sintering of HfB2/SiC and HfB2/HfC/SiC composite powders obtained by self-propagating high-temperature synthesis. J Alloys Compd 2009...2008; 91:10:3448-50. 9. Carmen M Carney. Oxidation resistance of hafnium diboride—silicon carbide from 1400 to 2000 °C. J Mater Sci 2009; 44:20:5673-81

  9. Effects of HfB2 and HfN Additions on the Microstructures and Mechanical Properties of TiB2-Based Ceramic Tool Materials

    Directory of Open Access Journals (Sweden)

    Jing An

    2017-04-01

    Full Text Available The effects of HfB2 and HfN additions on the microstructures and mechanical properties of TiB2-based ceramic tool materials were investigated. The results showed that the HfB2 additive not only can inhibit the TiB2 grain growth but can also change the morphology of some TiB2 grains from bigger polygons to smaller polygons or longer ovals that are advantageous for forming a relatively fine microstructure, and that the HfN additive had a tendency toward agglomeration. The improvement of flexural strength and Vickers hardness of the TiB2-HfB2 ceramics was due to the relatively fine microstructure; the decrease of fracture toughness was ascribed to the formation of a weaker grain boundary strength due to the brittle rim phase and the poor wettability between HfB2 and Ni. The decrease of the flexural strength and Vickers hardness of the TiB2-HfN ceramics was due to the increase of defects such as TiB2 coarse grains and HfN agglomeration; the enhancement of fracture toughness was mainly attributed to the decrease of the pore number and the increase of the rim phase and TiB2 coarse grains. The toughening mechanisms of TiB2-HfB2 ceramics mainly included crack bridging and transgranular fracture, while the toughening mechanisms of TiB2-HfN ceramics mainly included crack deflection, crack bridging, transgranular fracture, and the core-rim structure.

  10. Development and Application of Interatomic Potentials for Ultra High Temperature Ceramics (UHTC): ZrB2 and HfB2

    Science.gov (United States)

    Lawson, John W.; Daw, Murray; Bauschlicher

    2012-01-01

    Ultra high temperature ceramics (UHTC) including ZrB2 and HfB2 are characterized by high melting point, good strength, and reasonable oxidation resistance. These materials are of interest for use as sharp leading edges for hypersonic vehicles among other applications. Progress in computational modeling of UHTCs has been limited in part due to the absence of suitable interatomic potentials. We present a Tersoff style parameterization of such potentials for ZrB2 and HfB2 appropriate for atomistic simulations. Parameters are fit to data generated from ab initio calculations. The accuracy of the potentials is assessed against further ab initio data. As a first non ]trivial application, molecular dynamics simulations are performed to evaluate the thermal conductivity of single crystals and the thermal resistance of high symmetry grain boundaries.

  11. Lattice Thermal Conductivity of Ultra High Temperature Ceramics (UHTC) ZrB2 and HfB2 from Atomistic Simulations

    Science.gov (United States)

    Lawson, John W.; Daw, Murray S.; Bauschlicher, Charles W.

    2012-01-01

    Ultra high temperature ceramics (UHTC) including ZrB2 and HfB2 have a number of properties that make them attractive for applications in extreme environments. One such property is their high thermal conductivity. Computational modeling of these materials will facilitate understanding of fundamental mechanisms, elucidate structure-property relationships, and ultimately accelerate the materials design cycle. Progress in computational modeling of UHTCs however has been limited in part due to the absence of suitable interatomic potentials. Recently, we developed Tersoff style parameterizations of such potentials for both ZrB2 and HfB2 appropriate for atomistic simulations. As an application, Green-Kubo molecular dynamics simulations were performed to evaluate the lattice thermal conductivity for single crystals of ZrB2 and HfB2. The atomic mass difference in these binary compounds leads to oscillations in the time correlation function of the heat current, in contrast to the more typical monotonic decay seen in monoatomic materials such as Silicon, for example. Results at room temperature and at elevated temperatures will be reported.

  12. Separating Test Artifacts from Material Behavior in the Oxidation Studies of HfB2 SiC at 2000 deg C and Above (POSTPRINT)

    Science.gov (United States)

    2012-02-01

    The powder mixtures were ball milled in isopropanol for 24 h with SiC grinding media, dried at room tem- perature, and subsequently dry milled for 12...h. Typical weight loss of the SiC grinding media after milling was 0.2 mg (0.2 wt% of the total batch). The powders were sieved through an 80-mesh...C. Tripp, and W. C. Graham, “High-Temperature Oxi- dation Behavior of a HfB2 Plus 20 v/o SiC Composite,” J. Electrochem . Soc., 122 [9] 1249–1254

  13. Separating Test Artifacts from Material Behavior in the Oxidation Studies of HfB2-SiC at 2000 degs C and Above (Preprint)

    Science.gov (United States)

    2011-11-01

    vol% SiC (HS). The powder mixtures were ball milled in isopropanol for 24 h with SiC grinding media, dried at room temperature, and subsequently dry...milled for 12 h. Typical weight loss of the SiC grinding media after milling was 0.2 mg (0.2 wt% of the total batch). The powders were sieved...Temperature Oxidation Behavior of a HfB2 Plus 20 v/o SiC Composite,” J. Electrochem . Soc. 122 [9] 1249–1254 (1971). 3. W.C. Tripp, H.H. Davis, H.C. Graham

  14. Ab initio Computations of the Electronic, Mechanical, and Thermal Properties of Ultra High Temperature Ceramics (UHTC) ZrB2 and HfB2

    Science.gov (United States)

    Lawson, John W.; Bauschlicher, Charles W.; Daw, Murray

    2011-01-01

    Refractory materials such as metallic borides, often considered as ultra high temperature ceramics (UHTC), are characterized by high melting point, high hardness, and good chemical inertness. These materials have many applications which require high temperature materials that can operate with no or limited oxidation. Ab initio, first principles methods are the most accurate modeling approaches available and represent a parameter free description of the material based on the quantum mechanical equations. Using these methods, many of the intrinsic properties of these material can be obtained. We performed ab initio calculations based on density functional theory for the UHTC materials ZrB2 and HfB2. Computational results are presented for structural information (lattice constants, bond lengths, etc), electronic structure (bonding motifs, densities of states, band structure, etc), thermal quantities (phonon spectra, phonon densities of states, specific heat), as well as information about point defects such as vacancy and antisite formation energies.

  15. Mechanical properties of ZrB2- and HfB2-based ultra-high temperature ceramics fabricated by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Zapata-Solvas, E. [Imperial College, London; Jayaseelan, D. [Imperial College, London; Lin, Hua-Tay [ORNL; Brown, P. [DSTL, Porton Down, Salisbury, Wiltshire, UK; Lee, W.E. [Imperial College, London

    2013-01-01

    Flexural strengths at room temperature, at 1400 C in air and at room temperature after 1 h oxidation at 1400 C were determined for ZrB2- and HfB2-based ultra-high temperature ceramics (UHTCs). Defects caused by electrical discharge machining (EDM) lowered measured strengths significantly and were used to calculate fracture toughness via a fracture mechanics approach. ZrB2 with 20 vol.% SiC had room temperature strength of 700 90 MPa, fracture toughness of 6.4 0.6 MPa, Vickers hardness at 9.8 N load of 21.1 0.6 GPa, 1400 C strength of 400 30 MPa and room temperature strength after 1 h oxidation at 1400 C of 678 15 MPa with an oxide layer thickness of 45 5 m. HfB2 with 20 vol.% SiC showed room temperature strength of 620 50 MPa, fracture toughness of 5.0 0.4 MPa, Vickers hardness at 9.8 N load of 27.0 0.6 GPa, 1400 C strength of 590 150 MPa and room temperature strength after 1 h oxidation at 1400 C of 660 25 MPa with an oxide layer thickness of 12 1 m. 2 wt.% La2O3 addition to UHTCs slightly reduced mechanical performance while increasing tolerance to property degradation after oxidation and effectively aided internal stress relaxation during spark plasma sintering (SPS) cooling, as quantified by X-ray diffraction (XRD). Slow crack growth was suggested as the failure mechanism at high temperatures as a consequence of sharp cracks formation during oxidation.

  16. Atrial natriuretic factor receptor guanylate cyclase, ANF-RGC, transduces two independent signals, ANF and Ca2+

    Directory of Open Access Journals (Sweden)

    Teresa eDuda

    2014-03-01

    Full Text Available Atrial natriuretic factor receptor guanylate cyclase, ANF-RGC, was the first discovered member of the mammalian membrane guanylate cyclase family. The hallmark feature of the family is that a single protein contains both the site for recognition of the regulatory signal and the ability to transduce it into the production of the second messenger, cyclic GMP. For over two decades, the family has been classified into two subfamilies, the hormone receptor subfamily with ANF-RGC being its paramount member, and the Ca2+ modulated subfamily, which includes the rod outer segment guanylate cyclases, ROS-GC1 and 2, and the olfactory neuroepithelial guanylate cyclase, ONE-GC. ANF-RGC is the receptor and the signal transducer of the most hypotensive hormones, atrial natriuretic factor (ANF and B-type natriuretic peptide (BNP. After binding these hormones at the extracellular domain it, at its intracellular domain, signals activation of the C-terminal catalytic module and accelerates the production of cyclic GMP. Cyclic GMP then serves the second messenger role in biological responses of ANF and BNP such as natriuresis, diuresis, vasorelaxation and anti-proliferation. Very recently another modus operandi for ANF-RGC was revealed. Its crux is that ANF-RGC activity is also regulated by Ca2+. The Ca2+ sensor neurocalcin  mediates this signaling mechanism. Strikingly, the Ca2+ and ANF signaling mechanisms employ separate structural motifs of ANF-RGC in modulating its core catalytic domain in accelerating the production of cyclic GMP. In this review the biochemistry and physiology of these mechanisms with emphasis on cardiovascular regulation will be discussed.

  17. Multiscale Modeling of Ultra High Temperature Ceramics (UHTC) ZrB2 and HfB2: Application to Lattice Thermal Conductivity

    Science.gov (United States)

    Lawson, John W.; Daw, Murray S.; Squire, Thomas H.; Bauschlicher, Charles W.

    2012-01-01

    We are developing a multiscale framework in computational modeling for the ultra high temperature ceramics (UHTC) ZrB2 and HfB2. These materials are characterized by high melting point, good strength, and reasonable oxidation resistance. They are candidate materials for a number of applications in extreme environments including sharp leading edges of hypersonic aircraft. In particular, we used a combination of ab initio methods, atomistic simulations and continuum computations to obtain insights into fundamental properties of these materials. Ab initio methods were used to compute basic structural, mechanical and thermal properties. From these results, a database was constructed to fit a Tersoff style interatomic potential suitable for atomistic simulations. These potentials were used to evaluate the lattice thermal conductivity of single crystals and the thermal resistance of simple grain boundaries. Finite element method (FEM) computations using atomistic results as inputs were performed with meshes constructed on SEM images thereby modeling the realistic microstructure. These continuum computations showed the reduction in thermal conductivity due to the grain boundary network.

  18. THERMODYNAMIC PROPERTIES OF SELECTED HFC REFRIGERANTS

    Science.gov (United States)

    Hydrofluorocarbon (HFC) refrigerants are possible alternatives to replace ozone-depleting chlorofluorocarbon and hydrochlorofluorocarbon (HCFC) refrigerants. The flammability of a proposed new refrigerant is a major consideration in assessing its utility for a particular applicat...

  19. Mitigating Noise for the HFC Upstream Channel

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Provides the methods to mitigate noise for the upstream channel over HFC networks. We first briefly discuss the HFC network topology, then we describe the sources of noise, the mechanism to form noise, the characteristics of their spectrum, etc. In light of the mechanism to form noise and the characteristics of their spectrum, many methods are put forward in this paper. These methods are evaluated with implementation.

  20. Comparison of different standards used in radioimmunoassay for atrial natriuretic factor (ANF)

    DEFF Research Database (Denmark)

    Rasmussen, Peter Have; Nielsen, M. Damkjær; Giese, J.

    1991-01-01

    , estimates of the ANF content in human plasma samples with different standard preparations as the reference showed a considerable variability. With the international standard as the gold reference (plasma ANF concentration 100%) the apparent plasma ANF concentrations measured with the other reference...

  1. Immunohistochemical localization of atrial natriuretic factor (ANF) in the excretory system of the rabbit parotid gland.

    Science.gov (United States)

    Valentino, B; Farina Lipari, E; Carini, F; Valenza, V

    1999-01-01

    The immunohistochemical localization of atrial natriuretic factor (ANF) in the rabbit parotid gland was performed using an antibody against rabbit ANF and avidin-biotin or streptoavidin as detector. Results showed positivity in cuboidal and columnar cells of intralobular ducts and in basal cells of extralobular and main excretory duct. These data support the hypothesis that ANF produced by intralobular ducts could act through a paracrine mechanism; ANF produced by extralobular and main ducts may play a role in the regulation of salivary composition.

  2. Productos anfóteros etoxilados en la tintura de la lana.

    OpenAIRE

    1989-01-01

    Se estudia la influencia de determinados compuestos anfóteros y de su grado de etoxilación, en el estado de agregación de dos colorantes ácidos y en la cinética de tintura de estos sobre la fibra de lana. Se aprecia la formación de complejos colorante-producto anfótero y su redisolución en la micela del compuesto anfótero; todo ello viene influenciado por la relación molar colorante-producto anfótero y por el grado de etoxilación de éste. Las cinéticas de tintura en presencia de producto anfó...

  3. Research on Transport Properties of HFC-227ea

    Institute of Scientific and Technical Information of China (English)

    Lin Shi; Xiaojun Liu; Yuanyuan Duan; Lizhong Han; Mingshan Zhu

    2001-01-01

    HFC-227ea(1,1,1,2,3,3,3-heptafluoropropane) is considered as a promising refrigerant alternative, especially as a component in mixtures, to replace to CFC-12, HCFC-22 and R502. But reliable transport properties data for HFC-227ea are very limited. In this paper, experimental data of viscosity along the saturation line and gaseous thermal conductivity of HFC-227ea are given. The viscosity of HFC-227ea was measured with a capillary viscometer at temperatures between 263.15 K and 333.15 K along the saturation line and its uncertainty of the results is estimated to be no more than +3%. The thermal conductivity of gaseous HFC-227ea was also measured with a transient hot-wire instrument at temperatures between 259.28 K and 341.75 K and pressures up to 1.289MPa, and its uncertainty of the results is estimated to be less than +1%.

  4. Telemetry systems on cable tv networks (HFC); Sistema de telemetria sobre redes de TV a cabo (HFC)

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Christina [Furukawa Industrial S.A. Produtos Eletricos, Curitiba, PR (Brazil). E-mail: christi@furukawa.com.br

    1999-07-01

    This paper presents a telemetry system on the cable TV (Hybrid Fiber Coaxial network). This system conducts remote electric power using the HFC network as physical way. The telemetry system represents an aggregated value on this type of network. The HFC network is a network prepared for data transport under the concept of a future wide single band network.

  5. Transmission design in a multimode HFC network

    Science.gov (United States)

    Cambron, G. Keith

    1996-11-01

    Contemporary hybrid fiber coaxial (HFC) networks are capable of supporting a wide range of services including traditional analog video, telephony, digital video, and data services. Each service has unique performance or service requirements. This contribution examines transmission design for one such network. Pacific Bell's advanced communications network (ACN). The design methodology begins with a set of end to end service quality objectives. Network impairments, such as noise, distortion and delay, are allocated across the network elements using a set of standard network models. These models are a representative set of the actual field designs and bound the network operating parameters. Network components, headend equipment, and customer premises equipment are specified analytically or characterized empirically in relationship to the chosen impairment set. The component parameters are then included in analytical models to estimate overall network performance. In addition to the forward path transmission considerations examined by traditional coaxial network designers, other dimensions including power consumption, traffic demand, and message latency are taken into account. Analytical models are used to estimate the effects of multiple modulation schemes within the unified network. The variability introduced by on demand services such as telephony and interactive digital services changes the base computational domain from deterministic models to stochastic ones. These models are then used to set operating parameters at measurable points throughout the network for proof of performance prior to turn up, and for ongoing performance monitoring. For closure, empirical results are compared with model projections as a way of verifying and improving the predictive models.

  6. Lubricants for HFC-134a Compatible Rotary Compressors

    Science.gov (United States)

    Takaichi, Kenji; Sakai, Hisakazu

    In replacing CFC-12 with HFC-134a for refrigerator compressors, the compatibility with lubricating oil, and lubrication in general, are of major concern. HFC-134a dose not have adequate solubility with current lubricating oils because of its molecular structure. Current oils also do not provide enough lubricating action when using HFC-134a. A new oil and new materials have to be utilized in order to use HFC-134a. Developing a new lubricating oil involved numerous tests of different combinations of many polyolester synthetic oils and additives. One of the pre-evaluated methods was pursued via sealed tube tests. Lubricated parts were selected by studies involving a plane-on-roller type of wear test machine and by analyzing the traces of acid material commonly created during the lubricating action. The matrices of new lubricating oils and new lubricated materials were estimated based on durability tests conducted on compressors and refrigerators. Results showed that polyolester synthetic oils having a low total acid value and including certain quantities of additives did not break down into a tar-like substance and they did not produce composite particles in the operating compressors and refrigerators. The study also found that ceramics and anti-corrosion alloy steel possessed good adrasion-reducing qualities. Based on our evaluation, we will implement compressor reliability tests and apply HFC-134a to rotary compressors for refrigerators.

  7. Performance and heat transfer characteristics of HFC-134a and CFC-12 in a water chiller

    Energy Technology Data Exchange (ETDEWEB)

    Devotta, S.; Parande, M.G.; Patwardhan, V.R. [National Chemical Lab., Pune (India)

    1998-07-01

    A water chiller with an open reciprocating compressor has been used to comparatively assess the performance of HFC-134a with reference to CFC-12 under as close to identical conditions as possible. Performance characteristics of the chiller under retrofit conditions show that HFC-134a offers better cooling load and coefficients of performance vis-a-vis CFC-12 for identical operating conditions. Further heat transfer analysis of data for the condenser shows that the condensing heat transfer coefficients for HFC-134a are superior to CFC-12. The better performance of HFC-134a may be ascribed to the better heat transfer coefficient of HFC-134a over CFC-12. (Author)

  8. HCC-240fa氟化合成HFC-245fa技术进展%Progress on Synthesizing HFC -245fa by Fluorinating HCC -240fa

    Institute of Scientific and Technical Information of China (English)

    张国利; 杨会娥; 张文庆; 赵新堂

    2009-01-01

    HFC-245fa作为ODS发泡剂HCHC-141b和CFC-11的良好替代品,具有很好工业前景.全面综述了以HCC-240fa为原料合成HFC-245fa的各种工艺,并对HFC-245fa粗品的提纯进行详细的讨论.

  9. HFC-134a Export Expansion in Great Urgency

    Institute of Scientific and Technical Information of China (English)

    Zhang Lizhe

    2007-01-01

    @@ 1,1,1,2-tetrafluoroethane (HFC- 134a) is a new refrigerant. It has the features of no toxicity, no odor, no color, no inflammability, no explosion, good thermal stability and stable chemical property. Its ODP (ozone depletion potential) is zero. It has a refrigerating ability similar to F12.

  10. CMF Signal Processing Method Based on Feedback Corrected ANF and Hilbert Transformation

    Directory of Open Access Journals (Sweden)

    Tu Yaqing

    2014-02-01

    Full Text Available In this paper, we focus on CMF signal processing and aim to resolve the problems of precision sharp-decline occurrence when using adaptive notch filters (ANFs for tracking the signal frequency for a long time and phase difference calculation depending on frequency by the sliding Goertzel algorithm (SGA or the recursive DTFT algorithm with negative frequency contribution. A novel method is proposed based on feedback corrected ANF and Hilbert transformation. We design an index to evaluate whether the ANF loses the signal frequency or not, according to the correlation between the output and input signals. If the signal frequency is lost, the ANF parameters will be adjusted duly. At the same time, singular value decomposition (SVD algorithm is introduced to reduce noise. And then, phase difference between the two signals is detected through trigonometry and Hilbert transformation. With the frequency and phase difference obtained, time interval of the two signals is calculated. Accordingly, the mass flow rate is derived. Simulation and experimental results show that the proposed method always preserves a constant high precision of frequency tracking and a better performance of phase difference measurement compared with the SGA or the recursive DTFT algorithm with negative frequency contribution

  11. HyperANF: Approximating the Neighbourhood Function of Very Large Graphs on a Budget

    CERN Document Server

    Boldi, Paolo; Vigna, Sebastiano

    2010-01-01

    The neighbourhood function N(t) of a graph G gives, for each t, the number of pairs of nodes such that y is reachable from x in less that t hops. The neighbourhood function provides a wealth of information about the graph (e.g., it easily allows one to compute its diameter), but it is very expensive to compute it exactly. Recently, the ANF algorithm (approximate neighbourhood function) has been proposed with the purpose of approximating NG(t) on large graphs. We describe a breakthrough improvement over ANF in terms of speed and scalability. Our algorithm, called HyperANF, uses the new HyperLogLog counters and combines them efficiently through broadword programming; our implementation uses overdecomposition to exploit multi-core parallelism. With HyperANF, for the first time we can compute in a few hours the neighbourhood function of graphs with billions of nodes with a small error and good confidence using a standard workstation. Then, we turn to the study of the distribution of the shortest paths between re...

  12. Epileptische Anfälle nach zerebrovaskulären Ereignissen - Erste Auswertungen der Wiener Schlaganfalldatenbank

    Directory of Open Access Journals (Sweden)

    Glawar B

    2002-01-01

    Full Text Available Die Inzidenz isolierter epileptischer Anfälle nach Schlaganfällen wird in der Literatur zwischen 4 und 15 % angegeben. Die Wahrscheinlichkeit, eine Epilepsie nach einem zerebrovaskulären Ereignis zu entwickeln, liegt nach bisherigen Erkenntnissen zwischen 4 und 9 %. In einer prospektiven, multizentrischen Datenerhebung im Rahmen der Wiener Schlaganfalldatenbank werden seit Oktober 1998 Patienten mit der Diagnose Schlaganfall (nach der WHO-Definition und TIA, die innerhalb von 72 Stunden nach dem Ereignis zur Aufnahme an eine neurologische Abteilung kommen, erfaßt. Unter anderem werden auch Auftreten und Art von epileptischen Anfällen nach dem Ereignis beziehungsweise die Entwicklung einer vaskulären Epilepsie erfaßt. Für die vorliegende Fragestellung wurden die Daten von 1969 Patienten inklusive einer Dreimonatskontrolle ausgewertet. 82 dieser 1969 Patienten (= 4,2 % erlitten einen oder mehrere epileptische Anfälle nach dem Ereignis. Bei 55 Patienten (= 67 % trat der erste Anfall innerhalb von 24 Stunden, entsprechend einem Immediatanfall, auf. 22 Patienten (= 27 % hatten den ersten Anfall innerhalb der ersten 14 Tage, und bei 5 Personen (= 6 % wurde der erste Anfall erst zu einem späteren Zeitpunkt dokumentiert. Bei 67 % (n = 55 traten fokale Anfälle mit/ohne sekundäre Generalisierung auf, und bei ca. 33 % (n = 27 kam es zu phänomenologisch primär generalisierten Anfällen. In einer multivariaten Analyse zeigt sich, daß vor allem Patienten mit initial schwerer Behinderung nach dem NIH-Stroke Score ein höheres Risiko haben, epileptische Anfälle zu entwickeln. Bei 12 Patienten trat mehr als ein epileptischer Anfall auf, dies entspricht einer Inzidenz von 0,6 % für die Entwicklung einer vaskulären Epilepsie. In einem Beobachtungszeitraum von 3 Monaten sind noch nicht alle Patienten, die epileptische Anfälle entwickeln, erfaßt. Längere Beobachtungszeiträume und Kontrollen nach einem und nach zwei Jahren werden ausf

  13. Evaporation of refrigerant HFC 407C on plain tubes or at an improved surface; Evaporation du refrigerant HFC 407C sur des tubes lisses ou a surface amelioree

    Energy Technology Data Exchange (ETDEWEB)

    Zuercher, O.; Favrat, D.; Thome, J.R.; Kattan, N.; Nidegger, E. [Ecole polytechnique federale, Lab. d`energetique industrielle, Lausanne (Switzerland)

    1996-11-15

    The substitution of CFC refrigerants in refrigeration systems, heat pumps and organic Rankine cycles for heat recovery, requires good methods for predicting heat transfer of substitute fluids. The measurements in the LENI test facility (concentric tubes with water flowing in a counter-current flow) with HFC 407C, HFC 134a, HCFC 123, HFC 404a and HFC/HCFC 402A provide a new data bank for new refrigerants, and allow a coherent comparison with old refrigerants CFC 11, CFC 12, CFC/HCFC 502 and with existing correlations. The existing correlations were found to be inadequate. Because of this work, an improved flow pattern map and flow boiling model were developed, which resulted in a substantial progress in the accurate predict of heat transfer in plain, horizontal tubes for refrigerants without oil. The Kattan et al. correlation was programmed to calculate and compare predicted heat transfer coefficients to the new HFC 407C test data. The flow pattern map proposed by Kattan et al. was also programmed and compared to flow regimes observed for HFC 407C. It predicted the HFC 407C flow pattern data quite accurately. The original objective of the HFC 407C measurements was the validation of the Kattan et al. correlation applied to a zeotropic refrigerant blend. Local flow boiling heat transfer coefficients were measured for HFC 407C evaporating inside a microfin and a plain tube. In addition, microfin heat transfer augmentation relative to a plain tube was investigated. The presence of oil in the evaporator had a complex effect on heat transfer coefficients. Local flow boiling heat transfer coefficients were measured for refrigerant HFC 407C ester oil mixtures (Mobil EAL Arctic 68). A new thermodynamic approach for modeling mixtures of zeotropic refrigerant blends and lubricating oils was also developed. (author) figs., tabs., 14 refs.

  14. HFC-134A and HCFC-22 supermarket refrigeration demonstration and laboratory testing. Phase I. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-04-01

    Aspen Systems and a team of nineteen agencies and industry participants conducted a series of tests to determine the performance of HFC-134a, HCFC-22, and CFC-502 for supermarket application. This effort constitutes the first phase of a larger project aimed at carrying out both laboratory and demonstration tests of the most viable HFC refrigerants and the refrigerants they replace. The results of the Phase I effort are presented in the present report. The second phase of the project has also been completed. It centered on testing all viable HFC replacement refrigerants for CFC-502. These were HFC-507, HFC-404A, and HFC-407A. The latter results are published in the Phase II report for this project. As part of Phase I, a refrigeration rack utilizing a horizontal open drive screw compressor was constructed in our laboratory. This refrigeration rack is a duplicate of one we have installed in a supermarket in Clifton Park, NY.

  15. Analysis of Potential for HFC-23 Emission Reduction in China’s Fluorine Chemical Industry

    Institute of Scientific and Technical Information of China (English)

    LIN Hui; CUI Yong-Li; YANG Li-Rong

    2013-01-01

    China is one of the major producers of chlorodifluoromethane (HCFC-22) in the world. A large amount of fluoroform (HFC-23) is emitted during the production of HCFC-22. Emission factors of HFC-23 were calculated in accordance with the monitoring reports of eleven HFC-23 clean development mechanism (CDM) projects in China and the HFC-23 emissions in 2000-2010 as well as that in 2011-2020 were estimated and projected, respectively. It is expected that, by the end of 2020, emissions of HFC-23 in China will be as much as 230 Mt CO2-eq. If HCFC-22 producers voluntarily reduced HFC-23 emissions, it would contribute 3.2%-3.6%to the national CO2 emission reduction target for 2020.

  16. Proteomic analysis of anti-nutritional factors (ANF's) in soybean seeds as affected by environmental and genetic factors.

    Science.gov (United States)

    Maria John, K M; Khan, Farooq; Luthria, Davanand L; Garrett, Wesley; Natarajan, Savithiry

    2017-03-01

    The genotype (G), environment (E), and the relationship between G and E on soybean seed anti-nutritional factors (ANF's) were examined under three different agro-climatic conditions. The field trials were conducted at Maryland, South Carolina and South Dakota using nine region specific genotypes. At each location, the nine genotypes were grown with two planting/sowing dates. Differentially expressed protein spots from the two-dimensional gel electrophoresis were analyzed using mass spectrometry. Seven ANF's corresponding to soybean agglutinin and Kunitz trypsin inhibitor were identified based on the statistical significance levels at p<0.005. The G and E conditions (planting/sowing season) influences the ANF's content. This initial study suggests that early sowing reduces the total ANF's content irrespective of genotypes and their growing locations.

  17. CFC and HFC recycling equipments: Test performances; Qualificazione di dispositivi per il riciclaggio dei CFC e degli HFC

    Energy Technology Data Exchange (ETDEWEB)

    Picini, P.; Caropreso, G.; Cicoli, G.; Posarelli, M. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Ambiente; Pallotti, P. [ICF, Industria Componenti Frigoriferi Srl, Bologna (Italy)

    1996-12-01

    Actual regulatory conditions about ozone layer depleting chemicals set problems on their disposal and on the management of plants still using illegal CFCs. Anyway fluids that will replace CFCs (i.e. HFCs) will not be allowed to be spread into the atmosphere, due to their high costs and to the greenhouse effect. A viable solution would be the recovery, purification and recycle of contaminated fluids. ENEA (National Agency for New Technology, Energy and the Environment), in cooperation with ICF (Industria Componenti Frigoriferi) Company leader in the field of air refrigerating and conditioning, patented a device able to extract, to clean and to recycle CFC 12 and HFC 134a in the refrigerating systems. This paper presents experimental data from the qualification tests on a device performing the above mentioned operations regarding systems that use HFC 134a as process fluid.

  18. Efficient noble metal nanocatalysts supported on HfC(001 for O2 dissociation

    Directory of Open Access Journals (Sweden)

    Shiyan Wang

    2017-03-01

    Full Text Available The adsorption and dissociation of O2 on the M4 (M=Au, Pd, Pt clusters supported on HfC(001 (Hafnium Carbide are investigated using ab initio density functional theory calculations. The geometric and electronic structures are analyzed in detail. It is found that the dissociation barriers of O2 on Au4/HfC(001 (0.26 eV, Pd4/HfC(001 (0.49 eV and Pt4/HfC(001 (0.09 eV are much smaller than those on the clean surfaces of HfC(001 (1.60 eV, Au(111 (1.37 eV, Pd(111 (1.0 and 0.91 eV and Pt(111 (0.27–0.7 eV, respectively. The low dissociation barriers imply that the Pt4/HfC(001 exhibits the highest catalytic activity for O2 dissociation, and the Au4/HfC(001 and Pd4/HfC(001 may also be possible substitutes with lower cost for the current Pt/C catalyst for O2 dissociation. The present study is conductive to designing new efficient noble metal catalyst using HfC support for efficiently promoting O2 dissociation.

  19. Efficient noble metal nanocatalysts supported on HfC(001) for O2 dissociation

    Science.gov (United States)

    Wang, Shiyan; Zhang, Xilin; Zhang, Yanxing; Mao, Jianjun; Yang, Zongxian

    2017-03-01

    The adsorption and dissociation of O2 on the M4 (M=Au, Pd, Pt) clusters supported on HfC(001) (Hafnium Carbide) are investigated using ab initio density functional theory calculations. The geometric and electronic structures are analyzed in detail. It is found that the dissociation barriers of O2 on Au4/HfC(001) (0.26 eV), Pd4/HfC(001) (0.49 eV) and Pt4/HfC(001) (0.09 eV) are much smaller than those on the clean surfaces of HfC(001) (1.60 eV), Au(111) (1.37 eV), Pd(111) (1.0 and 0.91 eV) and Pt(111) (0.27-0.7 eV), respectively. The low dissociation barriers imply that the Pt4/HfC(001) exhibits the highest catalytic activity for O2 dissociation, and the Au4/HfC(001) and Pd4/HfC(001) may also be possible substitutes with lower cost for the current Pt/C catalyst for O2 dissociation. The present study is conductive to designing new efficient noble metal catalyst using HfC support for efficiently promoting O2 dissociation.

  20. Investigation into the conditions under which HFC134a may become flammable.

    CSIR Research Space (South Africa)

    Kramers, AP

    2002-01-01

    Full Text Available flammability limit of a propane/HFC134a/air mixture (Schröeder 1995). The contribution of the lubricant to the flammability of HFC134a was not well understood. The literature review and findings of the Tau Tona accident report (Department of Minerals... are also highly dependent on the type of ignition source and the volume of the vessel used. 2.1.2 Lubricants used with HFC134a Lubricants used with refrigerant 134a are mineral oils; alkyl benzenes; dibasic, polybasic and polyol esters...

  1. HFC双向宽带网%HFC-way Broadband Network

    Institute of Scientific and Technical Information of China (English)

    刘前

    2015-01-01

    With the rapid advent of the information society, information exchange has already become the most important resource, it is mainly for the three forms of images, integrated, intelligent and personal, all-digital service support. HFC network is a better access network, the best solution is the information superhighway broadband access networks.%信息交换已然成最重要的资源,它主要表现为图像、声音和数据3种形式。信息网络发展方向是数字化、综合化、智能化和个人化,支持全数字化业务。HFC网是目前较好的接入网,是信息高速公路宽带接入网的最佳方案。

  2. HFC-23 (CHF3 emission trend response to HCFC-22 (CHClF2 production and recent HFC-23 emission abatement measures

    Directory of Open Access Journals (Sweden)

    R. G. Prinn

    2010-08-01

    Full Text Available HFC-23 (also known as CHF3, fluoroform or trifluoromethane is a potent greenhouse gas (GHG, with a global warming potential (GWP of 14 800 for a 100-year time horizon. It is an unavoidable by-product of HCFC-22 (CHClF2, chlorodifluoromethane production. HCFC-22, an ozone depleting substance (ODS, is used extensively in commercial refrigeration and air conditioning, in the extruded polystyrene (XPS foam industries (dispersive applications and also as a feedstock in fluoropolymer manufacture (a non-dispersive use. Aside from small markets in specialty uses, HFC-23 has historically been considered a waste gas that was, and often still is, simply vented to the atmosphere. Efforts have been made in the past two decades to reduce HFC-23 emissions, including destruction (incineration in facilities in developing countries under the United Nations Framework Convention on Climate Change's (UNFCCC Clean Development Mechanism (CDM, and by process optimization and/or voluntary incineration by most producers in developed countries. We present observations of lower-tropospheric mole fractions of HFC-23 measured by "Medusa" GC/MSD instruments from ambient air sampled in situ at the Advanced Global Atmospheric Gases Experiment (AGAGE network of five remote sites (2007–2009 and in Cape Grim air archive (CGAA samples (1978–2009 from Tasmania, Australia. These observations are used with the AGAGE 2-D atmospheric 12-box model and an inverse method to produce model mole fractions and a "top-down" HFC-23 emission history. The model 2009 annual mean global lower-tropospheric background abundance is 22.6 (±0.2 pmol mol−1. The derived HFC-23 emissions show a "plateau" during 1997–2003, followed by a rapid ~50% increase to a peak of 15.0 (+1.3/−1.2 Gg/yr in 2006. Following this peak, emissions of HFC-23 declined rapidly to 8.6 (+0.9/−1.0 Gg/yr in 2009, the lowest annual emission of the past 15 years. We derive a 1990–2008 "bottom-up" HFC-23 emission history

  3. HFC-23 (CHF3 emission trend response to HCFC-22 (CHClF2 production and recent HFC-23 emission abatement measures

    Directory of Open Access Journals (Sweden)

    R. G. Prinn

    2010-05-01

    Full Text Available HFC-23 (also known as CHF3, fluoroform or trifluoromethane is a potent greenhouse gas (GHG, with a global warming potential (GWP of 14 800 for a 100-year time horizon. It is an unavoidable by-product of HCFC-22 (CHClF2, chlorodifluoromethane production. HCFC-22, an ozone depleting substance (ODS, is used extensively in commercial refrigeration and air conditioning, in the extruded polystyrene (XPS foam industries (dispersive applications and also as a feedstock in fluoropolymer manufacture (a non-dispersive use. Aside from small markets in specialty uses, HFC-23 has historically been considered a waste gas that was, and often still is, simply vented to the atmosphere. Efforts have been made in the past two decades to reduce HFC-23 emissions, including destruction (incineration in facilities in developing countries under the United Nations Framework Convention on Climate Change's (UNFCCC Clean Development Mechanism (CDM, and by process optimization and/or voluntary incineration by most producers in developed countries. We present observations of lower-tropospheric mole fractions of HFC-23 measured by "Medusa" GC/MSD instruments from ambient air sampled in situ at the Advanced Global Atmospheric Gases Experiment (AGAGE network of five remote sites and in Cape Grim air archive (CGAA samples (1978–2009 from Tasmania, Australia. These observations are used with the AGAGE 2-D atmospheric 12-box model and an inverse method to produce model mole fractions and a "top-down" HFC-23 emission history. The model 2009 annual mean global lower-tropospheric background abundance is 22.8 (±0.2 pmol mol−1. The derived HFC-23 emissions show a "plateau" during 1997–2003, followed by a rapid ~50% increase to a peak of 15.0 (+1.3/−1.2 Gg/yr in 2006. Following this peak, emissions of HFC-23 declined rapidly to 8.6 (+0.9/−1.0 Gg/yr in 2009, the lowest annual emission of the past 15 years. We derive a 1990–2008 "bottom-up" HFC-23 emission history using data

  4. HFC-134a refrigerant gas hydrate formation process and RIN model

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper, the macroscopic visualization experiments of HFC-134a refrigerant gas hydrate formation are investigated. According to the macroscopic photos and Mori's microscopic photos of HFC-134a hydrate formation process, the mechanism of gas hydrate formation is analyzed.A random inducement nucleation model is presented to describe the hydrate formation process. The factors affecting the fractal growth dimension in the model, such as step,branch increment and angle, are discussed.``

  5. HFC-134a emissions from mobile air conditioning in China from 1995 to 2030

    Science.gov (United States)

    Su, Shenshen; Fang, Xuekun; Li, Li; Wu, Jing; Zhang, Jianbo; Xu, Weiguang; Hu, Jianxin

    2015-02-01

    Since 1995, 1,1,1,2-tetrafluoroethane (CH2FCF3, HFC-134a) has become the most important substitute of CFC-12 in mobile air conditioning (MAC) in China and MAC sector has dominated all the emissions of HFC-134a. In this study, we developed an accurate, updated and county-level inventory of the HFC-134a emissions from MAC in China for the period of 1995-2030 with an improved bottom-up method. Our estimation indicated that the total HFC-134a emissions kept growing at increase rates of ∼100% per year for 1995-2000 and ∼34% per year for 2001-2010. In 2010, HFC-134a emissions from MAC in China reached 16.7 Gg (10.5-22.7 Gg at 95% confidential interval), equivalent to 21.7 Tg CO2 (CO2-eq). Furthermore, the emissions in China estimated in this study accounted for 9.8% of global HFC-134a emissions and 29.0% of total emissions from Non-Annex_I countries in 2010. Due to the more advanced social-economic conditions and more intensive ownership of automobiles, greater HFC-134a were observed to come from big cities in East China. Under a Business-as-usual (BAU) Scenario, projected emissions will grow to 89.4 (57.9-123.9) Gg (about 75.3-161.1 Tg CO2-eq) in 2030, but under an Alternative Scenario, 88.6% of the projected emissions under BAU scenario could be curbed. Our estimation demonstrates huge emission mitigation potential of HFC-134a in China's MAC sector.

  6. Estratégias de regeneração em anfíbios urodelos

    OpenAIRE

    2006-01-01

    p. 160-170 Na era das células-tronco, é interessante observar que a natureza resolveu o problema da regeneração com estratégias diferentes da restauração de tecidos por células indiferenciadas. Anfíbios urodelos são únicos, entre vertebrados, que têm a capacidade de regenerar córnea, retina, mandíbula, membros e secções do coração. A proliferação de células especializadas, transdiferenciação e desdiferenciação são importantes estratégias da regeneração de tritões e salamandras. ...

  7. (Vapour + liquid) equilibria of the {l_brace}trifluoromethane (HFC-23) + propane{r_brace} and {l_brace}trifluoromethane (HFC-23) + n-butane{r_brace} systems

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Mincheol; Yun, Yongju [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Shinlim-dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Shin, Moon Sam [Department of Cosmetic Science, Chungwoon University, Chungnam 350-701 (Korea, Republic of); Kim, Hwayong [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Shinlim-dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of)], E-mail: hwayongk@snu.ac.kr

    2009-12-15

    Isothermal (vapour + liquid) equilibrium data were measured for the two systems, {l_brace}trifluoromethane (HFC-23) + propane{r_brace} and {l_brace}trifluoromethane (HFC-23) + n-butane{r_brace}, at temperatures ranging from 283.15 K to 313.15 K at 10 K intervals. These experiments were performed with a circulating-type apparatus and on-line gas chromatography. Experimental data were well correlated by the Peng-Robinson equation of state using the Wong-Sandler mixing rules and the NRTL model.

  8. HFC245fa热物性数学模型及其lgp-h图%Modeling of Thermodynamic Properties and Transport Properties of HFC245fa and its lgp-h Diagram

    Institute of Scientific and Technical Information of China (English)

    张淑彦; 李岩; 张吉礼

    2011-01-01

    高温热泵适宜采用高温工质.HFC245fa被普遍认为是替代CFC11和HCFC123的HFCs类新型高温工质.本文以试验数据为基础,采用Soave-Redlich-Kwong方程,辩识了HFC245fa的状态方程;采用Wagner模型拟合了HFC245fa的饱和蒸汽压力模型;基于基团原理,建立了HFC245fa的气体定压比热容模型;由Clausius-Clapegron方程得到了HFC245fa的汽化潜热模型;利用多项式模型,拟合了HFC245fa的粘度﹑导热系数等迁移性质模型;最后,根据上述模型,绘制其lgp-h图.结果表明,上述模型和图表的精度能够满足HFC245fa在设备研发和制造中的实际应用.%High temperature work fluids are greatly suitable for the high temperature heat pump,and HFC245fa has been widely considered as a new high temperature work fluid to substitute CFC11 and HCFC123.Based on the experimental results of HFC245fa ,thermodynamic properties models and transport properties models of HFC245fa have been regressed.Namely ,the state equation and saturation vapor pressure equation of HFC245fa have been regressed respectively on the basis of Soave-RedlichKwong model and Wagner model.The vapor isotonic ratio specific heat model of HFC245fa has been created by the group theory.The evaporation latent heat model of HFC245fa has been finished by Clausius-Clapegron equation.Coefficient of viscosity,coefficient of heat transfer and other transport properties equations of HFC245fa have been built by various polynomial models.Finally,the lgp-h diagram of HFC245fa has been drawn out according to the built thermedynamic properties models.The error analyzed results of the thermodynamic properties models and transport properties models of HFC245fa show that all the models can meet the calculation precision demands of its applications in the development of the heat pump.

  9. HFC-134a Emissions in China: An Inventory for 1995-2030

    Science.gov (United States)

    Su, Shenshen; Fang, Xuekun; Wu, Jing; Li, Li; Hu, Jianxin; Han, Jiarui

    2014-05-01

    HFC-134a is the most important substitute of CFC-12 used in the mobile air-conditioner in China since 1995. The bottom-up method was used to estimate HFC-134a emissions in China, from 1995 to 2030, basing on updated automobile industry data and latest emission characters. From 1995, total HFC-134a emission has kept a high growth rate of nearly 60% per year, and reached 16,414.3 Mg (11,959.4-20,834.5 Mg) in 2010, which was equivalent to 23.5 Mt CO2-eq emissions. Furthermore, the emissions in China accounted for nearly half of total emissions of Non-AnnexI countries in 2008. As for provincial emissions in 2010, provinces with emission greater than 1,000 Mg are Guangdong, Shandong, Jiangsu and Beijing. Quantitative relationship between provincial HFC-134a emissions and GRP of the Tertiary Industry was used to estimate HFC-134a emissions at county level, and Hangzhou municipal district held the maximum emission intensity (4,605 Mg/10,000 km2). For HFC-134a, emissions calculated from the observations within 46 cities through Euler box model are in good agreement with the corresponding emissions estimated from the bottom-up method, verifying that the emission inventory at county level adequately describes the emission spatial pattern. For the future emissions of HFC-134a, projected emissions will reach 89,370.4 Mg (65,959.7- 114,068.2 Mg) in 2030 under the Business-as-usual (BAU) Scenario, but under the Alternative Scenario, a emission reduction potential of 88.6% of the projected BAU emissions would be obtained.

  10. Performance investigation of capillary tubes for machine tool coolers retrofitted with HFC-407C refrigerant

    Science.gov (United States)

    Wang, Fujen; Chang, Tongbou; Chiang, Weiming; Lee, Haochung

    2012-09-01

    The machine tool coolers are the best managers of coolant temperature in avoiding the deviation of spindle centerline for machine tools. However, the machine coolers are facing the compressed schedule to phase out the HCFC (hydro-chloro-floro-carbon) refrigerant and little attention has been paid to comparative study on sizing capillary tube for retrofitted HFC (hydro-floro-carbon) refrigerant. In this paper, the adiabatic flow in capillary tube is analyzed and modeled for retrofitting of HFC-407C refrigerant in a machine tool cooler system. A computer code including determining the length of sub-cooled flow region and the two phase region of capillary tube is developed. Comparative study of HCFC-22 and HFC-407C in a capillary tube is derived and conducted to simplify the traditional trial-and-error method of predicting the length of capillary tubes. Besides, experimental investigation is carried out by field tests to verify the simulation model and cooling performance of the machine tool cooler system. The results from the experiments reveal that the numerical model provides an effective approach to determine the performance data of capillary tube specific for retrofitting a HFC-407C machine tool cooler. The developed machine tool cooler system is not only directly compatible with new HFC-407C refrigerant, but can also perform a cost-effective temperature control specific for industrial machines.

  11. The large contribution of projected HFC emissions to future climate forcing.

    Science.gov (United States)

    Velders, Guus J M; Fahey, David W; Daniel, John S; McFarland, Mack; Andersen, Stephen O

    2009-07-01

    The consumption and emissions of hydrofluorocarbons (HFCs) are projected to increase substantially in the coming decades in response to regulation of ozone depleting gases under the Montreal Protocol. The projected increases result primarily from sustained growth in demand for refrigeration, air-conditioning (AC) and insulating foam products in developing countries assuming no new regulation of HFC consumption or emissions. New HFC scenarios are presented based on current hydrochlorofluorocarbon (HCFC) consumption in leading applications, patterns of replacements of HCFCs by HFCs in developed countries, and gross domestic product (GDP) growth. Global HFC emissions significantly exceed previous estimates after 2025 with developing country emissions as much as 800% greater than in developed countries in 2050. Global HFC emissions in 2050 are equivalent to 9-19% (CO(2)-eq. basis) of projected global CO(2) emissions in business-as-usual scenarios and contribute a radiative forcing equivalent to that from 6-13 years of CO(2) emissions near 2050. This percentage increases to 28-45% compared with projected CO(2) emissions in a 450-ppm CO(2) stabilization scenario. In a hypothetical scenario based on a global cap followed by 4% annual reductions in consumption, HFC radiative forcing is shown to peak and begin to decline before 2050.

  12. Role of excited CF3CFHO radicals in the atmospheric chemistry of HFC-134a

    DEFF Research Database (Denmark)

    Wallington, T.J.; Hurley, M.D.; Fracheboud, J.M.;

    1996-01-01

    CFHO* radicals limits the formation of CF3C(O)F and hence CF3COOH in the atmospheric degradation of HFC-134a. We estimate that the CF3COOH yield from atmospheric oxidation of HFC-134a is 7-20%. Vibrationally excited alkoxy radicals may play an important role in the atmospheric chemistry of other...

  13. Future atmospheric abundances and climate forcings from scenarios of global and regional hydrofluorocarbon (HFC) emissions

    Science.gov (United States)

    Velders, Guus J. M.; Fahey, David W.; Daniel, John S.; Andersen, Stephen O.; McFarland, Mack

    2015-12-01

    Hydrofluorocarbons (HFCs) are manufactured for use as substitutes for ozone-depleting substances that are being phased out globally under Montreal Protocol regulations. While HFCs do not deplete ozone, many are potent greenhouse gases that contribute to climate change. Here, new global scenarios show that baseline emissions of HFCs could reach 4.0-5.3 GtCO2-eq yr-1 in 2050. The new baseline (or business-as-usual) scenarios are formulated for 10 HFC compounds, 11 geographic regions, and 13 use categories. The scenarios rely on detailed data reported by countries to the United Nations; projections of gross domestic product and population; and recent observations of HFC atmospheric abundances. In the baseline scenarios, by 2050 China (31%), India and the rest of Asia (23%), the Middle East and northern Africa (11%), and the USA (10%) are the principal source regions for global HFC emissions; and refrigeration (40-58%) and stationary air conditioning (21-40%) are the major use sectors. The corresponding radiative forcing could reach 0.22-0.25 W m-2 in 2050, which would be 12-24% of the increase from business-as-usual CO2 emissions from 2015 to 2050. National regulations to limit HFC use have already been adopted in the European Union, Japan and USA, and proposals have been submitted to amend the Montreal Protocol to substantially reduce growth in HFC use. Calculated baseline emissions are reduced by 90% in 2050 by implementing the North America Montreal Protocol amendment proposal. Global adoption of technologies required to meet national regulations would be sufficient to reduce 2050 baseline HFC consumption by more than 50% of that achieved with the North America proposal for most developed and developing countries.

  14. 怎样维修"HFC-134a"制冷剂冰箱

    Institute of Scientific and Technical Information of China (English)

    徐进华

    2003-01-01

    @@ 美国杜邦(DuPont)公司推出了HFC-I34a,即四氯乙烷,它仍属于卤代烃类,但不含氟和溴,所以ODP(Ozone Deplete Potentia即臭氧消耗潜值)为零.家用电冰箱发展到现在,主要采用的制冷剂有:R12(CFC-12)、R134a(HFC-134a)、HC-600a等.

  15. Comparison of four inverse modelling systems applied to the estimation of HFC-125, HFC-134a, and SF6 emissions over Europe

    Science.gov (United States)

    Brunner, Dominik; Arnold, Tim; Henne, Stephan; Manning, Alistair; Thompson, Rona L.; Maione, Michela; O'Doherty, Simon; Reimann, Stefan

    2017-09-01

    Hydrofluorocarbons (HFCs) are used in a range of industrial applications and have largely replaced previously used gases (CFCs and HCFCs). HFCs are not ozone-depleting but have large global warming potentials and are, therefore, reported to the United Nations Framework Convention on Climate Change (UNFCCC). Here, we use four independent inverse models to estimate European emissions of the two HFCs contributing the most to global warming (HFC-134a and HFC-125) and of SF6 for the year 2011. Using an ensemble of inverse models offers the possibility to better understand systematic uncertainties in inversions. All systems relied on the same measurement time series from Jungfraujoch (Switzerland), Mace Head (Ireland), and Monte Cimone (Italy) and the same a priori estimates of the emissions, but differed in terms of the Lagrangian transport model (FLEXPART, NAME), inversion method (Bayesian, extended Kalman filter), treatment of baseline mole fractions, spatial gridding, and a priori uncertainties. The model systems were compared with respect to the ability to reproduce the measurement time series, the spatial distribution of the posterior emissions, uncertainty reductions, and total emissions estimated for selected countries. All systems were able to reproduce the measurement time series very well, with prior correlations between 0.5 and 0.9 and posterior correlations being higher by 0.05 to 0.1. For HFC-125, all models estimated higher emissions from Spain + Portugal than reported to UNFCCC (median higher by 390 %) though with a large scatter between individual estimates. Estimates for Germany (+140 %) and Ireland (+850 %) were also considerably higher than UNFCCC, whereas the estimates for France and the UK were consistent with the national reports. In contrast to HFC-125, HFC-134a emissions from Spain + Portugal were broadly consistent with UNFCCC, and emissions from Germany were only 30 % higher. The data suggest that the UK over-reports its HFC-134a emissions to

  16. Wide multi air-conditioning system using new cooling medium HFC407C; Shinreibai HFC407C saiyo no wide multi eakon

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    A multi air conditioner for a building was commercialized which used, as a substitute for the cooling medium HCFC(hydro chloro fluoro carbon)22, a new cooling medium HFC(hydro fluoro carbon)407C containing no chlorine atom that destroys the ozone layer. Since the new cooling medium HFC407C was a mixture of three kinds of cooling mediums having different boiling points, there were problems such as lowered performance through composition change in a heat exchanger and lowered lubricity due to no chlorine content. In order to solve these problems, high efficiency of the heat exchanger by the use of a new heat exchanger tube was contrived, as were improvement of the compressor, employment of a new lubricating oil, security of performance and enhancement of reliability through the optimum super heat control. As a result, the new cooling medium series was completed succeeding the advantage of the wide multi air-conditioners. (translated by NEDO)

  17. HEAT TRANSFER EVALUATION OF HFC-236FA IN CONDENSATION AND EVAPORATION

    Science.gov (United States)

    The report gives results of an evaluation of the shell-side heat transfer performance of hydrofluorocarbon (HFC)-236fa, which is considered to be a potential substitute for chlorofluorocarbon (CFC)-114 in Navy shipboard chillers, for both conventional finned [1024- and 1575-fpm (...

  18. HEAT TRANSFER EVALUATION OF HFC-236EA AND CFC-114 IN CONDENSATION AND EVAPORATION

    Science.gov (United States)

    The report gives results of a heat transfer evaluation of the refrigerants hexafluoropropane (HFC-236ea) and 1,1,2,2-dichloro-tetrafluoroethane (CFC-114). (NOTE: With the mandatory phase-out of chlorofluorocarbons (CFCs), as dictated by the Montreal Protocol and Clean Air Act Ame...

  19. HEAT TRANSFER EVALUATION OF HFC-236EA WITH HIGH PERFORMANCE ENHANCED TUBES IN CONDENSATION AND EVAPORATION

    Science.gov (United States)

    The report gives results of an evaluation of the heat transfer performance of pure hydrofluorocarbon (HFC)-236ea for high performance enhanced tubes which had not been previously used in Navy shipboard chillers. Shell-side heat transfer coefficient data are presented for condensa...

  20. MODELING AND DESIGN STUDY USING HFC-236EA AS AN ALTERNATIVE REFRIGERANT IN A CENTRIFUGAL COMPRESSOR

    Science.gov (United States)

    The report gives results of an investigation of the operation of a centrifugal compressor--part of a chlorofluorocarbon (CFC)-114 chiller installation--with the new refrigerant hydrofluorocarbon (HFC)-236ea, a proposed alternative to CFC-114. A large set of CFC-236ea operating da...

  1. The Earthscope USArray Array Network Facility (ANF): Metadata, Network and Data Monitoring, Quality Assurance During the Second Year of Operations

    Science.gov (United States)

    Eakins, J. A.; Vernon, F. L.; Martynov, V.; Newman, R. L.; Cox, T. A.; Lindquist, K. L.; Hindley, A.; Foley, S.

    2005-12-01

    The Array Network Facility (ANF) for the Earthscope USArray Transportable Array seismic network is responsible for: the delivery of all Transportable Array stations (400 at full deployment) and telemetered Flexible Array stations (up to 200) to the IRIS Data Management Center; station command and control; verification and distribution of metadata; providing useful remotely accessible world wide web interfaces for personnel at the Array Operations Facility (AOF) to access state of health information; and quality control for all data. To meet these goals, we use the Antelope software package to facilitate data collection and transfer, generation and merging of the metadata, real-time monitoring of dataloggers, generation of station noise spectra, and analyst review of individual events. Recently, an Antelope extension to the PHP scripting language has been implemented which facilitates the dynamic presentation of the real-time data to local web pages. Metadata transfers have been simplified by the use of orb transfer technologies at the ANF and receiver end points. Web services are being investigated as a means to make a potentially complicated set of operations easy to follow and reproduce for each newly installed or decommissioned station. As part of the quality control process, daily analyst review has highlighted areas where neither the regional network bulletins nor the USGS global bulletin have published solutions. Currently four regional networks (Anza, BDSN, SCSN, and UNR) contribute data to the Transportable Array with additional contributors expected. The first 100 stations (42 new Earthscope stations) were operational by September 2005 with all but one of the California stations installed. By year's end, weather permitting, the total number of stations deployed is expected to be around 145. Visit http://anf.ucsd.edu for more information on the project and current status.

  2. Lista actualizada de las especies de anfípodos (Peracarida: Gammaridea y Corophiidea) marinos invasores en México

    OpenAIRE

    2011-01-01

    Se presenta la lista actualizada de las especies invasoras de anfípodos gammáridos y corófidos marinos para México. Esta lista incluye 11 especies pertenecientes a los subórdenes Gammaridea y Corophiidea, agrupadas en cinco familias y seis géneros, que además proporciona información sobre la distribución, el hábitat, la historia natural y los antecedentes de la invasión, de acuerdo al Sistema Nacional de Información sobre Biodiversidad y elAnálisis de Riesgo. Las especies invasoras marinas pa...

  3. The Earthscope USArray Array Network Facility (ANF): Evolution of Data Acquisition, Processing, and Storage Systems

    Science.gov (United States)

    Davis, G. A.; Battistuz, B.; Foley, S.; Vernon, F. L.; Eakins, J. A.

    2009-12-01

    Since April 2004 the Earthscope USArray Transportable Array (TA) network has grown to over 400 broadband seismic stations that stream multi-channel data in near real-time to the Array Network Facility in San Diego. In total, over 1.7 terabytes per year of 24-bit, 40 samples-per-second seismic and state of health data is recorded from the stations. The ANF provides analysts access to real-time and archived data, as well as state-of-health data, metadata, and interactive tools for station engineers and the public via a website. Additional processing and recovery of missing data from on-site recorders (balers) at the stations is performed before the final data is transmitted to the IRIS Data Management Center (DMC). Assembly of the final data set requires additional storage and processing capabilities to combine the real-time data with baler data. The infrastructure supporting these diverse computational and storage needs currently consists of twelve virtualized Sun Solaris Zones executing on nine physical server systems. The servers are protected against failure by redundant power, storage, and networking connections. Storage needs are provided by a hybrid iSCSI and Fiber Channel Storage Area Network (SAN) with access to over 40 terabytes of RAID 5 and 6 storage. Processing tasks are assigned to systems based on parallelization and floating-point calculation needs. On-site buffering at the data-loggers provide protection in case of short-term network or hardware problems, while backup acquisition systems at the San Diego Supercomputer Center and the DMC protect against catastrophic failure of the primary site. Configuration management and monitoring of these systems is accomplished with open-source (Cfengine, Nagios, Solaris Community Software) and commercial tools (Intermapper). In the evolution from a single server to multiple virtualized server instances, Sun Cluster software was evaluated and found to be unstable in our environment. Shared filesystem

  4. Leakage Evaluation of Blend Refrigerant HCFC-22/HFC-152a for Auto mobile Air Conditioners%混合工质HCFC-22/HFC-152a汽车空调系统中泄漏性能分析

    Institute of Scientific and Technical Information of China (English)

    张华; 谷松

    2001-01-01

    A analysis of leakage is carried out for automobile air conditioner charged with HCFC-22/HFC-152a. The performance of automobile air conditioners doesn,t obvio usly change when leakage of the blend refrigerant happens. The HCFC-22/HFC-152a( 40/60mass%) can be used as alternative refrigerant in the transition period of e xisting automobile air conditioners.%对采用HCFC-22/HFC-152a混合制冷剂的汽车空调的 泄漏性能进行了分析;说明了HCFC-22/HFC-152a混合制冷剂不会因泄漏引起制冷系统性 能的显著变化,它可作为现有的汽车空调系统的过渡替代工质。

  5. ESTUDO TRIBOLÓGICO DE REVESTIMENTOS DE DLC COM GASES REFRIGERANTES HFC134A E HC600A

    National Research Council Canada - National Science Library

    Silverio, Marcio; Binder, Roberto; Mello, José Daniel Biasoli

    2011-01-01

    This work aims to study the effect of refrigerant gases HFC134a and HC600a in components coated with DLC, Diamond-like Carbon, as well as is to establish a methodology for tribology evaluating of them...

  6. A study of the time-resolved fluorescence spectrum and red edge effect of ANF in a room-temperature ionic liquid.

    Science.gov (United States)

    Hu, Zhonghan; Margulis, Claudio J

    2006-06-15

    In a recent article, we have analyzed using molecular dynamics simulations the steady-state red edge effect (REE) observed by Samanta and co-workers when the fluorescent probe 2-amino-7-nitrofluorene (ANF) is photoexcited at different wavelengths in 1-butyl-3-methylimidazolium ([BMIM+]) hexafluorophosphate ([PF6-]). In this letter, we predict the time- and wavelength-dependent emission spectra of ANF in the same ionic solvent. From the analysis of our simulated data, we are able to derive an approximate time scale for reorganization of the solvent around the solute probe. The effect that slow varying local liquid environments have on the overall time-dependent signal is also discussed.

  7. Novos anfíbios anuros das Serras costeiras do Brasil

    Directory of Open Access Journals (Sweden)

    Bertha Lutz

    1958-07-01

    , versando a autora as suas notas de campo, os caractéres morfológicos e o texto, ao passo que o autor contribuiria com a osteologia, os desenhos e as mensurações. O nome genérico foi sugerido pela autora e o específico pelo Sr. Antenor Leitão de Carvalho, em homenagem ao Professor Adolpho Lutz, um dos pioneiros no estudo dos anfíbios anuros do Brasil. A propósito da designação específica, a autora, filha de Adolpho Lutz, deseja publicar preliminarmente a Nota, por ela assinada, que segue sob a sua responsabilidade pessoal.

  8. Quantitative comparisons of absorption cross-section spectra and integrated intensities of HFC-143a

    Science.gov (United States)

    Le Bris, Karine; Graham, Laura

    2015-01-01

    The integrated absorption cross-sections of HFC-143a (CH3CF3) differ substantially in the literature. This leads to an important uncertainty on the value of the radiative efficiency of this molecule. The ambiguity on the absorption cross-sections of HFC-143a is highlighted by the existence of two significantly different datasets in the HITRAN database. To solve the issue, we performed high-resolution Fourier transform infrared laboratory measurements of HFC-13a and compared the spectra with the two HITRAN datasets and with the data from the Pacific Northwest National Laboratory (PNNL). The experimental methods and data analysis techniques are examined and typical sources of errors are discussed. The integrated intensities of the main bands are compared to other literature values. It was found that the integrated absorption cross-section values in the highest range - around 13.8 ×10-17 cm .molecule-1 in the 570-1500 cm-1 spectral band - show the most consistency between authors.

  9. HFC-152a and HFC-134a emission estimates and characterization of CFCs, CFC replacements, and other halogenated solvents measured during the 2008 ARCTAS campaign (CARB phase over the South Coast Air Basin of California

    Directory of Open Access Journals (Sweden)

    B. Barletta

    2011-03-01

    Full Text Available This work presents results from the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS study. Whole air samples were obtained on board research flights that flew over California during June 2008 and analyzed for selected volatile organic compounds, including several halogenated species. Samples collected over the South Coast Air Basin of California (SoCAB, which includes much of Los Angeles (LA County, were compared with samples from inflow air masses over the Pacific Ocean. The levels of many halocarbon species were enhanced significantly over the SoCAB, including compounds regulated by the Montreal Protocol and subsequent amendments. Emissions estimates of HFC-152a (1,1-difluoroethane, CH3CHF2; 0.82 ± 0.11 Gg and HFC-134a (1,1,1,2-tetrafluoroethane, CH2FCF3; 1.16 ± 0.22 Gg in LA County for 2008 were obtained using the observed HFC:carbon monoxide (CO enhancement ratio. Emission rates also were calculated for the SoCAB (1.60 ± 0.22 Gg yr−1 for HFC-152a and 2.12 ± 0.28 Gg yr−1 for HFC-134a and then extrapolated to the United States (32 ± 4 Gg yr−1 for HFC-152a and 43 ± 6 Gg yr−1 for HFC-134a using population data. In addition, emission rates of the two HFCs in LA County and SoCAB were calculated by a second method that utilizes air quality modeling. Emissions estimates obtained using both methods differ by less than 25% for the LA County and less than 45% for the SoCAB.

  10. Study of thermodynamic properties of HFC refrigerant mixtures for Loretz-cycled niew generation air-conditioning equipment; Lorentz cycle ka shinsedai kucho kikiyo HFC kei kongo reibai no netsu rikigaku seishitsu ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, K.; Sato, H. [Keio University, Tokyo (Japan). Faculty of Science and Technology

    1997-02-01

    This paper describes thermodynamic properties of HFC refrigerant mixtures for Lorentz-cycled new generation air-conditioning equipment. Equipment has been completed for simultaneous measurement of density and vapor-liquid equilibrium property, accurate measurement of latent heat of vaporization, and accurate measurement of specific heat at constant pressure in liquid phase. Final adjustment and preliminary measurements are currently conducted. Through analytical investigation using actually measured data of thermodynamic properties of HFC refrigerant mixtures, five state equations were obtained, i.e., modified Peng-Robinson state equation which can reproduce the vapor-liquid equilibrium property of refrigerant mixtures, modified Patel-Teja state equation, Helmholtz function type state equation which is applicable in the whole fluid region of refrigerant mixtures, and so on. An evaluation test equipment has been fabricated as a trial for Lorentz-cycled air-conditioning equipments using HFC refrigerant mixtures, and demonstration test is conducted to confirm the validity. 9 refs., 5 figs.

  11. Accurate measurement of phase equilibria and dissociation enthalpies of HFC-134a hydrates in the presence of NaCl for potential application in desalination

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dongyoung; Lee, Yohan; Choi, Wonjung; Seo, Yongwon [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of); Lee, Seungmin [Korea Institute of Industrial Technology, Busan (Korea, Republic of)

    2016-04-15

    Phase equilibria, structure identification, and dissociation enthalpies of HFC-134a hydrates in the presence of NaCl are investigated for potential application in desalination. To verify the influence of NaCl on the thermodynamic hydrate stability of the HFC-134a hydrate, the three-phase (hydrate (H) - liquid water (L{sub W}) - vapor (V)) equilibria of the HFC-134a+NaCl (0, 3.5, and 8.0 wt%)+water systems are measured by both a conventional isochoric (pVT) method and a stepwise differential scanning calorimeter (DSC) method. Both pVT and DSC methods demonstrate reliable and consistent hydrate phase equilibrium points of the HFC-134a hydrates in the presence of NaCl. The HFC- 134a hydrate is identified as sII via powder X-ray diffraction. The dissociation enthalpies (ΔH{sub d}) of the HFC-134a hydrates in the presence of NaCl are also measured with a high pressure micro-differential scanning calorimeter. The salinity results in significant thermodynamic inhibition of the HFC-134a hydrates, whereas it has little effect on the dissociation enthalpy of the HFC-134a hydrates. The experimental results obtained in this study can be utilized as foundational data for the hydrate-based desalination process.

  12. Experimental investigation of HFC407C/HC290/HC600a mixture in a window air conditioner

    Energy Technology Data Exchange (ETDEWEB)

    Jabaraj, D.B.; Avinash, P.; Lal, D. Mohan; Renganarayan, S. [Department of Mechanical Engineering, College of Engineering, Anna University, Chennai 600 025 (India)

    2006-09-15

    HCFC22, one of the widely used refrigerants in window air conditioners must be phased out soon as per the Montreal protocol. Presently, HFC407C is considered as a potential drop in substitute for HCFC22, but retrofitting HCFC22 systems with HFC407C with polyol ester oil (POE) is a major issue as HFC407C is immiscible with mineral oil. The miscibility issue of HFC407C with mineral oil was overcome with the addition of a HC blend to it. The above technoeconomic feasibility issues to retrofit the existing HCFC22 systems with an ozone friendly refrigerant and retain the energy efficiency of the system are challenges in the air conditioning sector. In this present work, an experimental analysis has been conducted in a window air conditioner retrofitted with eco-friendly refrigerant mixtures of HFC407C/HC290/HC600a without changing the mineral oil. Its performance, as well as energy consumption, was compared with the conventional one. It is observed that the mixtures demand lengthening of the condenser in order to maintain the discharge pressure within acceptable limits. This also resulted in better heat transfer at the condenser. Therefore, in this study, the condenser tube length was increased by 19% to suit the mixtures as compared to HCFC22. Compared to HCFC22, the refrigeration capacity of the new mixture was 9.54-12.76% higher than that of HCFC22, while the actual COP was found to be 11.91-13.24% higher than that of HCFC22. The overall performance has proved that the HFC407C/HC blend refrigerant mixture could be an eco-friendly substitute to phase out HCFC22. (author)

  13. Historical and projected emissions of HCFC-22 and HFC-410A from China's room air conditioning sector

    Science.gov (United States)

    Wang, Ziyuan; Fang, Xuekun; Li, Li; Bie, Pengju; Li, Zhifang; Hu, Jianxin; Zhang, Boya; Zhang, Jianbo

    2016-05-01

    Recent decades witnessed the increase in production and uses of HCFC-22 (chlorodifluoromethane, CHClF2) and its alternative, HFC-410A (a blend of difluoromethane and pentafluoroethane), in China in response to the booming of room air conditioners (RACs) for both domestic use and exports. HCFC-22 is an ozone-depleting substance under the Montreal Protocol, while both HCFC-22 and HFC-410A are greenhouse gases (GHGs). This study provides a most comprehensive consumption and emission inventory of refrigerants emissions (HCFC-22 and HFC-410A) from RAC sector during 1995-2014, for the first time. Our estimates show that HCFC-22 emissions increased from 0.7 Gg/yr in 1995 to 48.2 Gg/yr in 2014. The accumulative emissions contributed to global total HCFCs emissions by 4.4% (3.3%-6.1%) CFC-11-equivalent (CFC-11-eq) and 5.4% (4.1%-7.5%) CO2-equivalent (CO2-eq) during 1995-2012. If left uncontrolled, accumulative emissions of HFC-410A will be12.4 (7.1-20.2) CO2-eq Pg during 2015-2050, which can offset the global climate benefits achieved by the Montreal Protocol. The HFC-410A emissions from China's RAC sector are estimated to be of importance to both global HFCs emissions and China's GHG emissions. Further, we probed the emission mitigation performances of the current 2014 North American Proposal scenario and a modified more ambitious scenario. The emissions of two mitigation scenarios are only 28% and 22% of the emissions without mitigation actions, respectively. This study is the first effort to map the transition of eliminated substance HCFC-22 and its alternative HFC-410A in RAC sector. Therefore, alternative chemicals should be scrutinized with cautions before they are promoted and applied.

  14. Nematóides do Brasil 2ª parte: nematóides de anfíbios Brazilian nematodes - part 2: nematodes of amphibians

    Directory of Open Access Journals (Sweden)

    Joaquim Julio Vicente

    1990-01-01

    Full Text Available São reunidas neste trabalho todas as espécies de nematóides parasitas de anfíbios encontradas no Brasil, com dados suficientes para a sua identificação especifica. Na primeira parte que é o catálogo dos nematóides parasitos de anfíbios, são relacionadas nove superfamilias, quatorze famílias, vinte e quatro gêneros e sessenta e três espécies, sendo que destas, são dadas figuras e medidas. Na segunda parte que é o catálogo dos anfíbios hospedeiros, todos pertencentes à ordem Anura, são referidas seis famílias e cinqüenta e cinco espécies de anfíbios, estas com os nematóides respectivos. A identificação dos nematóides é auxiliada por chaves de determinação das superfamílias, famílias e gêneros, sendo a identificação específica feita através de quadros de medidas e figuras.A survey of nematode species parasitizing Brazilian amphibians is presented, with data enough to provide their specific identification. The first section refers to the catalogation of the species, related to 9 superfamilies, 14 families, 24 genera and 63 species that are figurated and included in measurement tables. The second section is concerned to the catalogue of host amphibians of the order Anura, with 6 families, and 55 species and their respective parasite nematodes. The identification of these helminths is achieved by means of keys to the superfamilies, families and genera. Specific determination is induced through the figures and tables as above mentioned.

  15. Antithetical modes of and the Ca2+ sensors targeting in ANF-RGC and ROS-GC1 membrane guanylate cyclases

    Directory of Open Access Journals (Sweden)

    Teresa eDuda

    2012-04-01

    Full Text Available The membrane guanylate cyclase family has been branched into three subfamilies: natriuretic peptide hormone surface receptors, Ca2+-modulated neuronal ROS-GC, and Ca2+-modulated odorant surface receptor ONE-GC. The first subfamily is solely modulated by the extracellularly-generated hormonal signals; the second, by the intracellularly-generated sensory and sensory-linked signals; and the third, by combination of these two. The present study defines (1 a new paradigm and (2 a new mechanism of Ca2+ signaling. (1 ANF-RGC, the prototype member of the surface receptor subfamily, is stimulated by free [Ca2+]i. The stimulation occurs via myristoylated form of neurocalcin , and both the guanylate cyclase and the calcium sensor neurocalcin are present in the glomerulosa region of the adrenal gland. (2 The EF-2, EF-3 and EF-4 hands of GCAP1 sense the progressive increment of [Ca2+]i and with a K1/2 of 100 nM turn ROS-GC1 OFF. In total reversal, the same EF hands upon sensing the progressive increment of [Ca2+]i with K1/2 turn ONE-GC ON. The findings suggest a universal Ca2+-modulated signal transduction theme of the membrane guanylate cyclase family; demonstrate that signaling of ANF-RGC occurs by the peptide hormones and also by [Ca2+]i signals; that for the Ca2+ signal transduction, ANF-RGC functions as a two-component transduction system consisting of the Ca2+ sensor neurocalcin  and the transducer ANF-RGC; and that the neurocalcin  in this case expands beyond its NCS family. Furthermore, the study shows a novel mechanism of the [Ca2+]i sensor GCAP1 where it acts as an antithetical NCS for the signaling mechanisms of ROS-GC1 and ONE-GC.

  16. MAKING VISIBLE THE INVISIBLE HAND OF NEOLIBERAL THOUGHT IN COSTA RICA: BIRTH AND TRAJECTORY OF THE NATIONAL ASSOCIATION OF ECONOMIC DEVELOPMENT (ANFE): 1958-1975

    OpenAIRE

    Marchena Sanabria, Jorge

    2011-01-01

    The following article deals with Costa Rican intellectual and political history, particularly focusedon the National Association of Economic Development (AsociaciónNacional de FomentoEconómico-ANFE).This organization was created in 1958 with the purpose of studying and transforming the Costa Rican State in the second half of the twentieth century and proposing policies aimed at developing the economy, making it more consistent with the free-market and reduction of state interventionliberal mo...

  17. Integrated services to the home and small business over a service-independent HFC network

    Science.gov (United States)

    Counterman, Raymond

    1995-11-01

    This paper proposes three different approaches to providing integrated digital services to small businesses and residential customers over modern hybrid fiber and coaxial (HFC) access networks. The target delivery system is one that is flexible and forms a multiservice, service- independent platform capable of providing a wide range of services (voice, video, data, and multimedia). The merits and limitations of the three approaches are explored. In the first approach, the common facilities of an HFC access network may be shared by the frequency partitioning of the coaxial plant's radio frequency spectrum. video, data, and telephony services each use different portions of this spectrum -- a service-dependent network. In the second approach, asynchronous transfer mode (ATM) transmission is used as the information delivery vehicle all the way to the home or small business, creating a more flexible delivery system. The ATM-based architecture is expected to support any service or service mix -- a service-independent network. In the third approach, a common transport protocol composed of both asynchronous and synchronous transfer modes (ATM/STM) is used. Such an approach could (1) provide a common interface between home/small business premises equipment and both the circuit and ATM switching networks; (2) meet a wide range of delay and throughput requirements; and (3) allow for many network migration scenarios.

  18. Experimental evaluation of automotive air-conditioning using HFC-134a and HC-134a

    Science.gov (United States)

    Nasution, Henry; Zainudin, Muhammad Amir; Aziz, Azhar Abdul; Latiff, Zulkarnain Abdul; Perang, Mohd Rozi Mohd; Rahman, Abd Halim Abdul

    2012-06-01

    An experimental study to evaluate the energy consumption of an automotive air conditioning is presented. In this study, these refrigerants will be tested using the experimental rig which simulated the actual cars as a cabin complete with a cooling system component of the actual car that is as the blower, evaporator, condenser, radiators, electric motor, which acts as a vehicle engine, and then the electric motor will operate the compressor using a belt and pulley system, as well as to the alternator will recharge the battery. The compressor working with the fluids HFC-134a and HC-134a and has been tested varying the speed in the range 1000, 1500, 2000 and 2500 rpm. The measurements taken during the one hour experimental periods at 2-minutes interval times for temperature setpoint of 20°C with internal heat loads 0, 500, 700 and 1000 W. The final results of this study show an overall better energy consumption of the HFC-134a compared with the HC-134a.

  19. 爆炸极限实验系统研制及二甲醚/HFC125的可燃性研究%Flammability Limits Measurement System and Flammability of Dimethyl Ether/HFC125

    Institute of Scientific and Technical Information of China (English)

    张可; 吴江涛; 高辉; 薛征欣

    2010-01-01

    根据ASTM E681-04及ANSI/ASHRAE Standard 34-2007标准,建立了一套全自动可燃性气体爆炸极限实验系统.该系统实际配气比例与设定比例的误差不超过±0.1%,配气比例的不确定度小于0.5%.对几种常见制冷剂的爆炸极限进行了测试,验证了系统的准确性.对二甲醚/HFC125混合气体的爆炸极限进行了实验研究,结果表明,加入HFC125后二甲醚的可燃性范围减小,当HFC125与二甲醚的体积比为4.6时达到临界抑爆点,但HFC125含量较低时对二甲醚的阻燃作用不明显.该测试结果为将二甲醚作为一种环保型制冷剂进行推广应用提供了安全参考.

  20. Sorbate rearrangement and cation migration in HFC-134 loaded NaY zeolite: a temperature dependent synchrotron powder diffraction study

    Energy Technology Data Exchange (ETDEWEB)

    Gualtieri, A.F. [Dipt. di Scienze della Terra, Univ. di Modena e R.E. (Italy); Norby, P. [Chemistry Dept., Univ. of Aarhus (Denmark); Grey, C.P. [Chemistry Dept., SUNY Stony Brook, NY (United States); Hanson, J.C. [Chemistry Dept., Brookhaven National Lab., Upton, NY (United States)

    2004-07-01

    The HFC-134/NaY binding has been monitored by temperature dependent X-ray powder diffraction. Diffraction patterns were obtained as a function of different loading levels to investigate the rearrangement of the cations and of the HFC-134 molecules, in the temperature range 100-230 K. In situ real-time data were collected using a Translating Imaging Plate System (TIPS) at the NSLS (USA). Rietveld structure refinements were performed for the HFC-134 (32 molecules per unit cell [m/uc=molecules per unit cell] or 4 molecules per supercage [m/sc=molecules per supercage]) using data collected from 100 to 230 K. A phase transition is observed at about 180 K (A to B phase transition) where a disordering of the HFC-134 molecule takes place and modification of its surrounding due to Na{sup +} migrations is observed. These results are preliminary and the experiment with the 32 m/uc should be repeated in order to assess whether the observed effect is reproducible. (orig.)

  1. Determination of the infrared cross sections and global warming potentials of 1,1,2-trifluorethane (HFC-143)

    Energy Technology Data Exchange (ETDEWEB)

    Clerbaux, C.; Colin, R. [Univ. Libre de Bruxelles, Brussels (Belgium)

    1994-11-01

    The Global Warming Potentials (GWPs) of CH2F-CHF2 (HFC-143) have been estimated for different time horizons. Radiative forcings associated with this CFC alternative have been derived relative to CFC-11 and CO2 by introducing laboratory measured absorption cross sections into a coupled chemical-radiative model.

  2. Accelerating growth of HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane) in the atmosphere

    NARCIS (Netherlands)

    Laube, J.C.; Martinerie, P.; Witrant, E.; Brenninkmeijer, C.A.M.; Bolder, M.; Rockmann, T.; van der Veen, C; Sturges, W.T.

    2010-01-01

    We report the first measurements of 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), a substitute for ozone depleting compounds, in air samples originating from remote regions of the atmosphere and present evidence for its accelerating growth. Observed mixing ratios ranged from below 0.01 ppt in deep f

  3. Performance studies on mechanical + adsorption hybrid compression refrigeration cycles with HFC 134a

    Energy Technology Data Exchange (ETDEWEB)

    Banker, N.D.; Dutta, P.; Srinivasan, K. [Department of Mechanical Engineering, Indian Institute of Science, Bangalore 560 012 (India); Prasad, M. [Thermal Systems Division, ISRO Satellite Centre, Bangalore 560 017 (India)

    2008-12-15

    This paper presents the results of an investigation on the efficacy of hybrid compression process for refrigerant HFC 134a in cooling applications. The conventional mechanical compression is supplemented by thermal compression using a string of adsorption compressors. Activated carbon is the adsorbent for the thermal compression segment. The alternatives of bottoming either mechanical or thermal compression stages are investigated. It is shown that almost 40% energy saving is realizable by carrying out a part of the compression in a thermal compressor compared to the case when the entire compression is carried out in a single-stage mechanical compressor. The hybrid compression is feasible even when low grade heat is available. Some performance indictors are defined and evaluated for various configurations. (author)

  4. HFC网络升级优化方案%HFC Network Upgrade Optimum Proposal

    Institute of Scientific and Technical Information of China (English)

    黄映辉; 庄嘉

    2012-01-01

    Aiming at the transmission structure of the Secondary transmission network which use the high power light transmission module that was ubiquity in the HFC network at present.This kind of transmission structure is difficult to sustain the broadband services,the ITV and other new business.This paper discusses the design proposal and characteristic which adapt to INT structure interactive broadband Secondary transmission platform%针对目前HFC网络普遍存在的二级传输网采用大功率光发模块的传输结构,难以支撑宽带业务及互动电视等新业务的问题,论述了为适应三网融合构建交互式宽带网络二级传输网光平台的设计方案及特点。

  5. Inventory and mitigation opportunities for HFC-134a emissions from nonprofessional automotive service

    Science.gov (United States)

    Zhan, Tao; Potts, Winston; Collins, John F.; Austin, Jeff

    2014-12-01

    Many vehicle owners in the United States recharge their vehicles' air conditioning systems with small containers of hydrofluorocarbon-134a (HFC-134a, CH2FCF3), at a frequency estimated to be once every year on average. Such nonprofessional service produces immediate emissions of this potent greenhouse gas during service and from the residual heel in partially used containers. The nonprofessional operations are also associated with increased delayed refrigerant emissions that occur because owners are less likely to repair leaks than professional technicians. In California, an estimated 1.3 million nonprofessional service operations performed each year generate 0.27 ± 0.07 million metric ton CO2 equivalent (MMTCO2e) of immediate emissions and 0.54 ± 0.08 MMTCO2e of delayed emissions, using a Global Warming Potential of 1300 for HFC-134a. The immediate emissions can be largely mitigated by a regulation that requires self-sealing valves and improved labeling instructions on the containers, a deposit-return-recycling program for the containers, and a consumer education program. If 95% of the used containers were to be returned by consumers for recycling of the container heel, the annual immediate emissions would be reduced by 0.26 ± 0.07 MMTCO2e. In the United States, an estimated 24 million nonprofessional service operations are performed each year, generating 5.1 ± 1.4 MMTCO2e of immediate emissions and 10.4 ± 1.5 MMTCO2e of delayed emissions. Mitigation measures equivalent to the California regulation would reduce nationwide immediate emissions by 4.9 ± 1.4 MMTCO2e, if 95% of the used cans were returned for recycling. These business-as-usual emissions and mitigation potentials are projected to stay approximately constant until around 2022, and remain at significant levels into the 2030s.

  6. 管束效应对HFC245fa与HCFC123膜状凝结换热影响%Effect of Inundation on Film Condensation of HFC245fa and HCFC123 on Horizontal Tubes

    Institute of Scientific and Technical Information of China (English)

    马志先; 张吉礼; 孙德兴

    2012-01-01

    建立试验系统、改进试验方法,试验研究HFC245fa与HCFC123在光管与3种强化换热管(2D-A,3D-A与3D-B)管束外冷凝换热特性.试验管束由4列排深为5排的列管构成,换热管公称外径为19.05 mm、有效换热长度为500 mm.试验中,利用改进的Wilson图解法获得水侧对流传热系数,通过轮转试验方法消除管束试验中各试验管换热本构差异等因素对管束效应测试分析的影响.试验结果表明,Kern模型预测值与HFC245fa与HCFC123光管管束外凝结换热结果偏差随试验热通量升高而增大;管束效应对光管与三维表面强化管(3D-B)凝结换热影响比其对二维表面低肋管(2D-A)影响显著;管束效应对HFC245fa在3D-B管外凝结换热影响在n>3后超过Nusselt管束模型预测值;HFC245fa在3D-B管束外凝结换热性能随管排深度的变化规律与其在光管管束外的变化规律及Nusselt模型显示规律明显不同.%A test facility was constructed to perform shell-side condensation testing, and test results are presented for HFC245fa and HCFC123 using horizontal tube bundles (4 lines×5 rows) consist of smooth tubes and 2D-A, 3D-A and 3D-B enhanced tubes. Effect of inundation on the condensation heat transfer coefficient (CHTC) is considered in the study. The nominal diameter of test tubes is 19.05 mm and the active length of the test section is 500 mm. In the experiment, water-side convection heat transfer coefficient of enhanced tube was gained by modified Wilson plot method and the tube row effect is studied by a designed method with high precision. The results show that the deviation between CHTC of HCFC123 and HFC245fa on smooth tube bundle and that predicted by Kern's model increased with the increase of heat flow rate; Inundation effect significantly affects CHTC of smooth and 3D-B tubes, but lightly affects that of 2D-A tubes; Inundation effect of HFC245fa on 3D-B tubes is more severity than that predicted by Nusselt model for

  7. Purification of chimeric heavy chain monoclonal antibody EG2-hFc using hydrophobic interaction membrane chromatography: an alternative to protein-A affinity chromatography.

    Science.gov (United States)

    Sadavarte, Rahul; Spearman, Maureen; Okun, Natalie; Butler, Michael; Ghosh, Raja

    2014-06-01

    Heavy chain monoclonal antibodies are being considered as alternative to whole-IgG monoclonal antibodies for certain niche applications. Protein-A chromatography which is widely used for purifying IgG monoclonal antibodies is also used for purifying heavy chain monoclonal antibodies as these molecules possess fully functional Fc regions. However, the acidic conditions used to elute bound antibody may sometimes also leach protein-A, which is immunotoxic. Low pH conditions also tend to make the mAb molecules unstable and prone to aggregation. Moreover, protein-A affinity chromatography does not remove aggregates already present in the feed. Hydrophobic interaction membrane chromatography (or HIMC) has already been studied as an alternative to protein-A chromatography for purifying whole-IgG monoclonal antibodies. This paper describes the use of HIMC for capturing a humanized chimeric heavy chain monoclonal antibody (EG2-hFC). Binding and eluting conditions were suitably optimized using pure EG2-hFC. Based on this, an HIMC method was developed for capture of EG2-hFC directly from cell culture supernatant. The EG2-hFc purity obtained in this single-step process was high. The glycan profiles of protein-A and HIMC purified monoclonal antibody samples were similar, clearly demonstrating that both techniques captured similarly glycosylated population of EG2-hFc. Moreover, this technique was able to resolve aggregates from monomeric form of the EG2-hFc.

  8. Final Project Closeout Report for Sprint Hydrogen Fuel Cell (HFC) Deployment Project in California, Gulf Coast and Eastern Seaboard Markets

    Energy Technology Data Exchange (ETDEWEB)

    Kenny, Kevin [Sprint, Reston, VA (United States); Bradley, Dwayne [Burns & McDonnell, Kansas City, MO (United States)

    2015-09-01

    Sprint is one of the telecommunications industry leaders in the deployment of hydrogen fuel cell (HFC) systems to provide backup power for their mission critical wireless network facilities. With several hundred fuel cells commissioned in California, states in the gulf coast region, and along the upper eastern seaboard. A strong incentive for advancing the integration of fuel cells into the Sprint network came through the award of a Department of Energy (DOE) grant focused on Market Transformation activities for project (EE0000486). This grant was funded by the 2009 American Recovery and Reinvestment Act (ARRA). The funding provided by DOE ($7.295M) was allocated to support the installation of 260 new HFC systems, equipped with an on-site refillable Medium Pressure Hydrogen Storage Solution (MPHSS), as well as for the conversion of 21 low pressure hydrogen systems to the MPHSS, in hopes of reducing barriers to market acceptance.

  9. Isosteric heats of adsorption extracted from experiments of ethanol and HFC 134a on carbon based adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    El-Sharkawy, Ibrahim I.; Saha, Bidyut B.; Koyama, Shigeru [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga-koen 6-1, Kasuga-shi, Fukuoka 816-8580 (Japan); Srinivasan, Kandadai [School of Engineering and Logistics, Charles Darwin University, Darwin NT 0909 (Australia)

    2007-03-15

    The purpose of this paper is to provide empirical correlations for isosteric heats of adsorption on carbon based adsorbents for two refrigerants namely ethanol and HFC 134a. A non-dimensional correlation which partitions the contributions of the concentration and temperature dependence is proposed. The correlation is tested out against data obtained from experimental isotherms of ethanol adsorption on activated carbon fibers [ACF (A-20) and ACF (A-15)] and HFC 134a on two specimens of activated carbon powders and one specimen of carbon granules. It is expected that the suggested correlation will be useful for designers of adsorption chillers where indenting heat inventories fulcrums on the magnitude of isosteric heat of adsorption. (author)

  10. (Vapour + liquid) equilibria of the {l_brace}pentafluoroethane (HFC-125) + dimethyl ether (DME){r_brace} system

    Energy Technology Data Exchange (ETDEWEB)

    Im, Jihoon [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Shinlim-dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Lee, Gangwon [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Shinlim-dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Lee, Jongcheon [LG Chem, Ltd. Research Park, Yuseong-gu, Science Town, Daejeon 305-380 (Korea, Republic of); Kim, Hwayong [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Shinlim-dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of)]. E-mail: hwayongk@snu.ac.kr

    2006-12-15

    Binary (vapour + liquid) equilibrium data were measured for the {l_brace}pentafluoroethane (HFC-125) + dimethyl ether (DME){r_brace} system at temperatures from (313.15 to 363.15) K. These experiments were carried out with a circulating-type apparatus with on-line gas chromatography. The experimental data were correlated well by the Peng-Robinson Stryjek-Vera equation of state using the Wong-Sandler mixing rules.

  11. Study on the Interaction Coefficients in PR Equation with vdW Mixing Rules for HFC and HC Binary Mixtures

    Science.gov (United States)

    Chen, Jian-Xin; Hu, Peng; Chen, Ze-Shao

    2008-12-01

    The Peng-Robinson equation of state with the van der Waals mixing rules was used to correlate vapor-liquid equilibrium (VLE) data for HFC/HC, HFC/HFC, and HC/HC binary mixtures. The interaction parameter k ij was obtained for every binary mixture. It was assumed that k ij has contributions from the two components, and each component has its own constant contribution factor k i for the mixture, and the values of k ij indicate the degree in difference of properties between the two components. Therefore, the interaction parameters k ij is proposed as: k ij = k i - k j . The values of the mixing factor k i for Hydrofluorocarbons (HFCs) and Hydrocarbons (HCs), including propane, isobutane, n-butane, R23, R32, R125, R143a, R134a, R152a, R227ea R236fa, R236ea, and R245fa, were obtained by least-square fitting. In total, 39 refrigerant binary mixtures were analyzed on the basis of this method, and the results showed good agreement with experimental data. The overall average absolute deviations of pressure and vapor mole fraction are 1.3 % and 0.0089, respectively.

  12. Extrinsic allergic alveolitis with eosinophil infiltration induced by 1,1,1,2-tetrafluoroethane (HFC-134a): a case report.

    Science.gov (United States)

    Ishiguro, Takashi; Yasui, Masahide; Nakade, Yusuke; Kimura, Hideharu; Katayama, Nobuyuki; Kasahara, Kazuo; Fujimura, Masaki

    2007-01-01

    A 22-year-old woman was admitted with symptoms of dyspnea and fever with pulmonary infiltrates noted on her chest X-ray study. She developed these symptoms in the workplace; her job included the removal of body hair using a diode-laser with 1,1,1,2-tetrafluoroethane (HFC134a, an alternative to chlorofluorocarbon) as a coolant. A chest X-ray examination revealed ground-glass opacities in the lower lung fields, and a chest computed tomographic study showed diffuse centrilobular opacities. An examination of the bronchoalveolar lavage fluid revealed increased lymphocytes with a slight increase in the number of eosinophils. An examination of the transbronchial biopsy specimens revealed eosinophil infiltration. A peripheral blood eosinophilia was also seen. The patient's symptoms, chest X-ray findings, and arterial blood gas analysis all returned to normal within a week. A challenge test of 1,1,1,2-tetrafluoroethane (HFC134a) inhalation was performed, which resulted in an elevation of body temperature, the development of a cough, and laboratory data indicating increased inflammation. We then determined the patient's diagnosis to be extrinsic allergic alveolitis with eosinophil infiltration, caused by HFC134a.

  13. Measurements of HFC-134a and HCFC-22 in groundwater and unsaturated-zone air: implications for HFCs and HCFCs as dating tracers

    Science.gov (United States)

    Haase, Karl B.; Busenberg, Eurybiades; Plummer, L. Niel; Casile, Gerolamo; Sanford, Ward E.

    2014-01-01

    A new analytical method using gas chromatography with an atomic emission detector (GC–AED) was developed for measurement of ambient concentrations of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) in soil, air, and groundwater, with the goal of determining their utility as groundwater age tracers. The analytical detection limits of HCFC-22 (difluorochloromethane, CHClF2) and HFC-134a (1,2,2,2-tetrafluoroethane, C2H2F4) in 1 L groundwater samples are 4.3 × 10− 1 and 2.1 × 10− 1 pmol kg− 1, respectively, corresponding to equilibrium gas-phase mixing ratios of approximately 5–6 parts per trillion by volume (pptv). Under optimal conditions, post-1960 (HCFC-22) and post-1995 (HFC-134a) recharge could be identified using these tracers in stable, unmixed groundwater samples. Ambient concentrations of HCFC-22 and HFC-134a were measured in 50 groundwater samples from 27 locations in northern and western parts of Virginia, Tennessee, and North Carolina (USA), and 3 unsaturated-zone profiles were collected in northern Virginia. Mixing ratios of both HCFC-22 and HFC-134a decrease with depth in unsaturated-zone gas profiles with an accompanying increase in CO2 and loss of O2. Apparently, ambient concentrations of HCFC-22 and HFC-134a are readily consumed by methanotrophic bacteria under aerobic conditions in the unsaturated zone. The results of this study indicate that soils are a sink for these two greenhouse gases. These observations contradict the previously reported results from microcosm experiments that found that degradation was limited above-ambient HFC-134a. The groundwater HFC and HCFC concentrations were compared with concentrations of chlorofluorocarbons (CFCs, CFC-11, CFC-12, CFC-113) and sulfur hexafluoride (SF6). Nearly all samples had measured HCFC-22 or HFC-134a that were below concentrations predicted by the CFCs and SF6, with many samples showing a complete loss of HCFC-22 and HFC-134a. This study indicates that HCFC-22 and HFC-134

  14. Ticks infesting amphibians and reptiles in Pernambuco, Northeastern Brazil Carrapatos infestando anfíbios e répteis em Pernambuco, Nordeste do Brasil

    Directory of Open Access Journals (Sweden)

    Filipe Dantas-Torres

    2008-12-01

    Full Text Available Ticks infesting amphibians and reptiles in the State of Pernambuco are reviewed, based on the current literature and new collections recently carried out by the authors. To date, three tick species have been found on amphibians and reptiles in Pernambuco. Amblyomma fuscum appears to be exclusively associated with Boa constrictor, its type host. Amblyomma rotundatum has a relatively low host-specificity, being found on toads, snakes, and iguana. Amblyomma dissimile has been found on a lizard and also small mammals (i.e., rodents and marsupials. New tick-host associations and locality records are given.Os carrapatos encontrados infestando anfíbios e répteis no Estado de Pernambuco são revisados com base na literatura atual e em novas coletas realizadas recentemente pelos autores. Até o momento, três espécies de carrapatos foram encontradas sobre anfíbios e répteis em Pernambuco. Amblyomma fuscum parece estar exclusivamente associado à Boa constrictor, seu hospedeiro-tipo. Amblyomma rotundatum tem uma especificidade parasitária relativamente baixa, sendo encontrado em sapos, serpentes e iguana. Amblyomma dissimile já foi encontrado sobre um lagarto e também sobre pequenos mamíferos (isto é, roedores e marsupiais. Novas associações carrapato-hospedeiro e novos registros de localidades são apresentados.

  15. Finnish 2002 inventory of HFC, PFC and SF{sub 6} emissions

    Energy Technology Data Exchange (ETDEWEB)

    Oinonen, T.

    2004-07-01

    Year 2002 was exceptional in the history of Finnish HFC, PFC and SF6 (F-gases for short) use. For the first time in a 10 year period, emissions fell from previous year. High uncertainty of the 2001 estimate prevents reliable quantification of the magnitude of this decrease, but simulation results suggest that the decrease may have been around 10%. The 2002 level of F-gases emissions was 530 Gg CO{sub 2}-equivalent. This figure corresponds to 0.6% of total Finnish greenhouse gas emissions.The inventory of F-gases was improved in 2003 by extending the coverage of the survey used to gather data. The number of respondents surveyed was quadrupled to some 1 000 individuals, and more than 750 of these responded. This improvement had an effect of bringing down the inventory uncertainty (measured by the width of the 95 % certainty range) from 400 Gg CO{sub 2}-eq. in 2001 to 140 Gg CO{sub 2}-eq. in 2002. Best efforts were made to ensure the accuracy, transparency, consistency, completeness and comparability of the inventory, as mandated in the guidelines of the United Nations Framework Convention on Climate Change. Although reporting to the UNFCCC is the primary purpose of this document, it is hoped that the information contained within is of use also in formulating strategies to combat climate change both in Finland and in European Union. (orig.)

  16. Perverse effects of carbon markets on HFC-23 and SF6 abatement projects in Russia

    Science.gov (United States)

    Schneider, Lambert; Kollmuss, Anja

    2015-12-01

    Carbon markets are considered a key policy tool to achieve cost-effective climate mitigation. Project-based carbon market mechanisms allow private sector entities to earn tradable emissions reduction credits from mitigation projects. The environmental integrity of project-based mechanisms has been subject to controversial debate and extensive research, in particular for projects abating industrial waste gases with a high global warming potential (GWP). For such projects, revenues from credits can significantly exceed abatement costs, creating perverse incentives to increase production or generation of waste gases as a means to increase credit revenues from waste gas abatement. Here we show that all projects abating HFC-23 and SF6 under the Kyoto Protocol’s Joint Implementation mechanism in Russia increased waste gas generation to unprecedented levels once they could generate credits from producing more waste gas. Our results suggest that perverse incentives can substantially undermine the environmental integrity of project-based mechanisms and that adequate regulatory oversight is crucial. Our findings are critical for mechanisms in both national jurisdictions and under international agreements.

  17. Consideration of Sludge Formation in HFC-134a / Polyol Ester oil Refrigeration System

    Science.gov (United States)

    Yamamoto, Tsutomu; Yamamoto, Tethuya; Simizu, Yasuhiko; Nakayama, Yoshinori; Takizawa, Kikuo

    A refrigeration test employing HFC-134a and polyol ester oil was carried out in order to make clear the causes of the sludge formation in the capillary tube. Compressors used were two types: a hermetic reciprocating compressor and a rotary compressor. Installed dryer contained desiccant of the compound zeolite type. The results showed that the amount of capillary sludge increased as the compressor temperature rose. The capillary sludge was determined to consist of desiccant and metal dust for the reciprocating compressor, and of tar-like substance for the rotary compressor. Thermal stability test which was used to check the degree of deterioration of the ester oil, suggested that the presence of desiccant and high compressor temperature might produce tar-like substance by the break down and polymerization of the ester oil. In addition, it was confirmed that factors affecting the sludge formation were the dirtiness of the refrigeration circuit for the reciprocating compressor, and the presence of desiccant, for the rotary compressor.

  18. Study on two stage activated carbon/HFC-134a based adsorption chiller

    Science.gov (United States)

    >K Habib,

    2013-06-01

    In this paper, a theoretical analysis on the performance of a thermally driven two-stage four-bed adsorption chiller utilizing low-grade waste heat of temperatures between 50°C and 70°C in combination with a heat sink (cooling water) of 30°C for air-conditioning applications has been described. Activated carbon (AC) of type Maxsorb III/HFC-134a pair has been examined as an adsorbent/refrigerant pair. FORTRAN simulation program is developed to analyze the influence of operating conditions (hot and cooling water temperatures and adsorption/desorption cycle times) on the cycle performance in terms of cooling capacity and COP. The main advantage of this two-stage chiller is that it can be operational with smaller regenerating temperature lifts than other heat-driven single-stage chillers. Simulation results shows that the two-stage chiller can be operated effectively with heat sources of 50°C and 70°C in combination with a coolant at 30°C.

  19. Research on Processing Multi-noise Signals in Mobile Multimedia Communication Based on HFC

    Institute of Scientific and Technical Information of China (English)

    ZENG Qinghui; HU Xiulin; ZHUANG Zhaowen; ZENG Yilin; MA Tao; ZHANG Yunyu; YANG Haizhou

    2001-01-01

    As well known, noise is one of mainobjects of signals processing. However, many kindsof noises are affecting widely on mobile communica-tion along with enlarging mobile networks and rapidlyincreasing application range of multimedia commu-nication. The noises include 1/f noise; burst noise;multichannel noise; thermal and shot noise etc., allof which here are called "multi-noise (MN)" and atthe same time, the signals affected by "multi-noise"is called "multi-noise signals". The article firstly ana-lyzes some disturbance factors of multi-noise that af-fects multimedia flow. Then, it describes briefly hi-erarchical fuzzy control (HFC) technology and its ap-plication procedure for online identification and con-trolling multi-noise signals in mobile multimedia com-munication networks. Lastly, how to make a specialhierarchical fuzzy control program is also discussed.With different test examples, the article demonstratesthe ability of hierarchical fuzzy control to identifyflow states and control signal distortion in multime-dia communication. The hierarchical fuzzy controland hierarchical fuzzy control programs provide anadvanced efficient tool for supervising the distributedstates of multi-noise and movement characteristics ofmulti-noise signals in mobile multimedia communica-tion.

  20. Dynamic chiral-at-metal stability of tetrakis(d/l-hfc)Ln(III) complexes capped with an alkali metal cation in solution.

    Science.gov (United States)

    Lin, Yiji; Zou, Fang; Wan, Shigang; Ouyang, Jie; Lin, Lirong; Zhang, Hui

    2012-06-14

    Chiral tetrakis(β-diketonate) Ln(III) complexes Δ-[NaLa(d-hfc)(4)(CH(3)CN)] (1) and Λ-[NaLa(l-hfc)(4) (CH(3)CN)] (2) (d/l-hfc(-) = 3-heptafluo-robutylryl-(+)/(-)-camphorate) are a pair of enantiomers and crystallize in the same Sohncke space group (P2(1)2(1)2(1)) with dodecahedral (DD) geometry. Typically positive and negative exciton splitting patterns around 320 nm were observed in the solid-state circular dichroism (CD) spectra of complexes 1 and 2, which indicate that their shell configurational chiralities are Δ and Λ, respectively. The apparent bisignate couplets in the solid-state CD spectra of [CsLn(d-hfc)(4)(H(2)O)] [Ln = La (3), Yb (5)] and [CsLn(l-hfc)(4)(H(2)O)] [Ln = La (4), Yb (6)] show that they are a pair of enantiomers and their absolute configurations are denoted Δ and Λ, respectively. The crystallographic data of 5 reveals that its coordination polyhedron is the square antiprism (SAP) geometry and it undergoes a phase transition from triclinic (α phase, P1) to monoclinic (β phase, C2) upon cooling. The difference between the two phases is brought about by the temperature dependent behaviour of the coordination water molecules, but this did not affect the configurational chirality of the Δ-SAP-[Yb(d-hfc)(4)](-) moiety. Furthermore, time-dependent CD, UV-vis and (19)F NMR were applied to study the solution behavior of these complexes. It was found that the chiral-at-metal stability of the three pairs of complexes is different and affected by both the Ln(3+) and M(+) ion size. The results show that the Cs(+) cation can retain the metal center chirality and stablize the structures of [Ln(d/l-hfc)(4)](-) or the dissociated tris(d/l-hfc)Ln(III) species in solution for a longer time than that of the Na(+) cation, and it is important that the Cs(+) ion successfully lock the configurational chirality around the Yb(3+) center of the complex species in solution. This is reasoned by the short Cs(+)···FC, Cs(+)···O-Yb and Cs(+)···Yb(3

  1. Estimated 2017 refrigerant emissions of 2,3,3,3-tetrafluoropropene (HFC-1234yf) in the United States resulting from automobile air conditioning.

    Science.gov (United States)

    Papasavva, Stella; Luecken, Deborah J; Waterland, Robert L; Taddonio, Kristen N; Andersen, Stephen O

    2009-12-15

    In response to recent regulations and concern over climate change, the global automotive community is evaluating alternatives to the current refrigerant used in automobile air conditioning units, 1,1,1,2-tetrafluoroethane, HFC-134a. One potential alternative is 2,3,3,3-tetrafluoropropene (HFC-1234yf, also known as HFO-1234yf). We have developed a spatially and temporally resolved inventory of likely future HFC refrigerant emissions from the U.S. vehicle fleet in 2017, considering regular, irregular, servicing, and end-of-life leakages. We estimate the annual leak rate emissions for each leakage category for a projected 2017 U.S. vehicle fleet by state, and spatially apportion these leaks to a 36 km square grid over the continental United States. This projected inventory is a necessary first step in analyzing for potential atmospheric and ecosystem effects, such as ozone and trifluoroacetic acid production, that might result from widespread replacement of HFC-134a with HFC-1234yf.

  2. Lista preliminar dos anfíbios da Estação Ecológica do Taim, Rio Grande do Sul, Brasil

    Directory of Open Access Journals (Sweden)

    Stela Máris Pires Gayer

    1988-01-01

    Full Text Available Das 67 espécies de anfíbios conhecidas do Rio Grande do Sul, 18 foram coletadas na Estação Ecológica do Taim, no sudeste deste Estado. Os Leptodactylidae são os mais diversificados na área, e os Hylidae os mais numerosos em indivíduos.Out of the 67 species of amphibians known from Rio Grande do Sul, 18 were collected at the Estação Ecológica do Taim, in the southeastern part of that State. The Leptodactylidae are the most diversified ir the area, whereas the Hylidae were the most numerous in individuais

  3. Diversidade de anfíbios e répteis Squamata na região do baixo rio Purus, Amazônia Central, Brasil

    OpenAIRE

    Waldez,Fabiano; Menin,Marcelo; Vogt,Richard Carl

    2013-01-01

    A região do baixo rio Purus na Amazônia Central - Brasil representa uma área de relevante interesse para conservação de anfíbios e répteis. No entanto, há pouca informação disponível sobre estes grupos taxonômicos para áreas de florestas de terra firme e florestas de várzea, principais paisagens nesta região. Nesse estudo, realizamos uma amostragem ampla em esforço e área, em dois períodos: 2004-2005 e 2009-2010. Utilizamos técnicas complementares eficientes na amostragem da herpetofauna em f...

  4. Diversidade de anfíbios e répteis Squamata na região do baixo rio Purus, Amazônia Central, Brasil

    OpenAIRE

    Fabiano Waldez Silva Guimarães; Marcelo Menin; Richard Carl Vogt

    2013-01-01

    A região do baixo rio Purus na Amazônia Central – Brasil representa uma área de relevante interesse para conservação de anfíbios e répteis. No entanto, há pouca informação disponível sobre estes grupos taxonômicos para áreas de florestas de terra firme e florestas de várzea, principais paisagens nesta região. Nesse estudo, realizamos uma amostragem ampla em esforço e área, em dois períodos: 2004-2005 e 2009-2010. Utilizamos técnicas complementares eficientes na amostragem da herpetofauna em f...

  5. Anfípodos hiperídeos (Crustacea: Peracarida del Parque Nacional Isla del Coco, Costa Rica, Pacífico Tropical Oriental

    Directory of Open Access Journals (Sweden)

    Rebeca Gasca

    2012-11-01

    Full Text Available Los anfípodos hiperídeos son uno de los grupos de crustáceos pelágicos más frecuentemente encontrados y están entre los más diversos del zooplancton marino. Para determinar la composición de especies de anfípodos hipéridos que habitan las aguas alrededor del Parque Nacional Isla del Coco, Costa Rica, se analizaron 12 muestras de zooplancton. Estas fueron recolectadas mediante arrastres verticales y horizontales con una red de plancton con mallas de 200 y 500 micras y 49cm de diámetro en la boca. Se encontró un total de 22 especies pertenecientes a 17 géneros y 12 familias. Se presenta el listado faunístico de este grupo junto con datos acerca de su taxonomía, su distribución en el área de estudio y su distribución general. La mayor parte de las especies registradas en esta zona han sido reportadas en estudios previos referentes a la región del Pacífico Tropical Oriental y en particular en aguas oceánicas de Costa Rica. Encontramos ocho especies que representan nuevos registros para aguas del Pacífico costarricense, lo que incrementa en un 26% (a 38 el número de especies de hipéridos conocidos en Costa Rica. Las especies más frecuentes fueron Lestrigonus shoemakeri, L. bengalensis, Hyperioides sibaginis y Phronimosis spinifera. Se espera que muestreos adicionales tanto de aguas superficiales como profundas expandan el conocimiento de la diversidad del grupo en esta área protegida.

  6. Atmospheric observations for quantifying emissions of point-source synthetic greenhouse gases (CF4, NF3 and HFC-23)

    Science.gov (United States)

    Arnold, Tim; Manning, Alistair J.; Li, Shanlan; Kim, Jooil; Park, Sunyoung; Fraser, Paul J.; Mitrevski, Blagoj; Steele, L. Paul; Krummel, Paul B.; Mühle, Jens; Weiss, Ray F.

    2016-04-01

    The fluorinated species carbon tetrafluoride (CF4; PFC-14), nitrogen trifluoride (NF3) and trifluoromethane (CHF3; HFC-23) are potent greenhouse gases with 100-year global warming potentials of 6,630, 16,100 and 12,400, respectively. Unlike the majority of CFC-replacement compounds that are emitted from fugitive and mobile emission sources, these gases are largely emitted from large single point sources - semiconductor manufacturing facilities (all three), aluminium smelting plants (CF4) and chlorodifluoromethane factories (HFC-23). In this work we show the potential for atmospheric measurements to understand regional sources of these gases and to highlight emission 'hotspots'. We target our analysis on measurements from two Advanced Global Atmospheric Gases Experiment (AGAGE) long term monitoring sites that are particularly sensitive to regional emissions of these gases: Gosan on Jeju Island in the Republic of Korea and Cape Grim on Tasmania in Australia. These sites measure CF4, NF3 and HFC-23 alongside a suite of greenhouse and stratospheric ozone depleting gases every two hours using automated in situ gas-chromatography mass-spectrometry instrumentation. We couple each measurement to an analysis of air history using the regional atmospheric transport model NAME (Numerical Atmospheric dispersion Modelling Environment) driven by 3D meteorology from the Met Office's Unified Model, and use a Bayesian inverse method (InTEM - Inversion Technique for Emission Modelling) to calculate yearly emission changes over a decade (2005-2015) at high spatial resolution. At present these gases make a small contribution to global radiative forcing, however, given that their impact could rise significantly and that point sources of such gases can be mitigated, atmospheric monitoring could be an important tool for aiding emissions reduction policy.

  7. Quantifying India's HFC emissions from whole-air samples collected on the UK-India Monsoon campaign

    Science.gov (United States)

    Say, Daniel; Ganesan, Anita; O'Doherty, Simon; Bauguitte, Stephane; Rigby, Matt; Lunt, Mark

    2017-04-01

    With a population exceeding 1 billion and a rapidly expanding economy, greenhouse gas (GHG) emissions from India are of global significance. As of 2010, India's anthropogenic GHG emissions accounted for 5.6% of the global total, with this share predicted to grow significantly in the coming decades. We focus here on hydrofluorocarbons (HFCs), a diverse range of potent GHGs, whose role as replacements for ozone-depleting CFCs and HCFCs in air-conditioning and refrigeration applications (among others) has led to rapid atmospheric accumulation. Recent efforts to reduce their consumption (and subsequent emission) culminated in an amendment to the Montreal Protocol; member states are now required to phase-down their use of HFCs, with the first cuts planned for 2019. Despite the potential climate implications, atmospheric measurements of HFCs in India, required for quantifying their emissions using top-down inverse methods, have not previously existed. Here we present the first Indian hydrofluorocarbon (HFC) observations, obtained during two months of low altitude (<2000 m) flights. Of the 176 whole air samples collected on board the UK's NERC-FAAM (Facility for Airborne Atmospheric Measurements) research aircraft, the majority were obtained above the Indo-Gangetic Plains of Northern India, where population density is greatest. Using a small subset of samples filled above the Arabian Sea, we derive compound specific baselines, to which the remaining samples are compared. Significant mole fraction enhancements are observed for all major HFCs, indicating the presence of regional emissions sources. Little enhancement is observed in the concentration of various HFC predecessors, including CFCs, suggesting India's success in phasing out the majority of ozone depleting substances. Using these atmospheric observations and the NAME (Numerical Atmospheric dispersion Modelling Environment) atmospheric transport model, we present the first regional HFC flux estimates for India.

  8. Performance testing of a semi-hermetic compressor with HFC-236EA and CFC-114 at chiller conditions. Report for December 1993-May 1994

    Energy Technology Data Exchange (ETDEWEB)

    Kazachki, G.S.; Hendriks, R.V.

    1994-12-31

    The paper gives results of tests of both HFC-236ea and CFC-114 at a range of temperatures covering surface craft and submarine chiller conditions. Evaporating temperatures ranged from 1.7 to 12.8 C, and condensing temperatures from 40.6 to 65.6 C, in order to develop a nine-point test map. Polyol ester oil was used with the refrigerants. The tests evaluated suction and discharge pressures, their difference and ratio, cooling capacity, electric power input, compressor energy efficiency ratio (coefficient of performance), electric current, and compressor volumetric and isentropic energy efficiency. Compressor discharge, motor winding, and oil temperature were also monitored. HFC-236ea is one of the strongest candidates for a CFC-114 alternative in surface craft and submarine chillers. Some material compatibility and oil miscibility work has also been performed in support of HFC-236ea as a refrigerant.

  9. HFO1234ze(E) And HFC134a Flow Boiling Inside a 4mm Horizontal Smooth Tube

    OpenAIRE

    Longo, Giovanni A.; Mancin, Simone; Righetti, Giulia; Zilio, Claudio

    2016-01-01

    Nowadays, the substitution of HFC134a with low GWP refrigerants is one of the most important challenge for refrigeration and air conditioning. The possible substitutes include natural refrigerants, such as HC600 (Butane) and HC600a (Isobutane), and also synthetic refrigerants, such as HFO1234yf and HFO1234ze(E). The HC refrigerants exhibit very low GWP, 3 and 4 HC600a and HC600 respectively, good thermodynamic and transport properties, and pressure and volumetric performance very similar to H...

  10. Accelerating growth of HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane) in the atmosphere

    DEFF Research Database (Denmark)

    Laube, J.C.; Martinerie, P.; Witrant, E.

    2010-01-01

    We report the first measurements of 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), a substitute for ozone depleting compounds, in air samples originating from remote regions of the atmosphere and present evidence for its accelerating growth. Observed mixing ratios ranged from below 0.01 ppt in deep...... firn air to 0.59 ppt in the current northern mid-latitudinal upper troposphere. Firn air samples collected in Greenland were used to reconstruct a history of atmospheric abundance. Year-on-year increases were deduced, with acceleration in the growth rate from 0.029 ppt per year in 2000 to 0.056 ppt per...

  11. Lattice vibrational properties of transition metal carbides (TiC, ZrC and HfC)

    Indian Academy of Sciences (India)

    K S Upadhyaya; Ajay Kumar Singh; Atul Pandey; S N Pathak; A K Singh

    2005-02-01

    Lattice vibrational properties of transition metal carbides (TiC, ZrC and HfC) have been presented by including the effects of free-carrier doping and three-body interactions in the rigid shell model. The short-range overlap repulsion is operative up to the second neighbour ions. An excellent agreement has been obtained between theory and experiment for their phonon dispersion curves and Debye temperature variations. It is concluded that the contributions of free-carrier doping and three-body interactions are essential for the description of the lattice dynamics of these carbides.

  12. Substituting HCFC-22 for HFC-410A: an environmental impact trade-off between the ozone depletion and climate change regimes

    Science.gov (United States)

    Wang, Z.; Fang, X.; Zhang, J.

    2015-12-01

    After the phase-out of hydrochlorofluorocarbons (HCFCs) as ozone-depleting substances pursuant to the requirements of the Montreal Protocol, hydrofluorocarbons (HFCs) are worldwide used as substitutes although the bulk of them are potent greenhouse gases (GHGs). Therefore, the alternation may bring side effect on global climate change. The trade-off of its environmental impacts between the ozone depletion and climate change regimes necessitates a quantification of the past and future consumption and emissions of both the original HCFCs and their alternative HFCs. Now a dilemma arise in China's RAC industry that HCFC-22, which has an ozone-depleting potential (ODP) of 0.055, has been replaced by HFC-410A, which is a blended potent GHG from respective 50% HFC-32 and HFC-125 with a global warming potential (GWP) of 1923.5. Here, we present our results of estimates of consumption and emissions of HCFC-22 and HFC-410A from 1994 to 2050. Historic emissions of HCFC-22 contributed to global total HCFCs by 4.0% (3.0%-5.6%) ODP-weighted. Projection under a baseline scenario shows future accumulative emissions of HFC-410A make up 5.9%-11.0% of global GWP-weighted HFCs emissions, and its annual contribution to national overall CO2 emissions can be 5.5% in 2050. This makes HCFC-22 and HFC-410A emissions of significant importance in ozone depletion and climate change regimes. Two mitigation scenarios were set to assess the mitigation performance under the North America Proposal and an accelerated schedule. In practice of international environmental agreement, "alternative to alternative" should be developed to avoid regrettable alternations.

  13. Emissions of CO2, CO, NOx, HC, PM, HFC-134a, N2O and CH4 from the global light duty vehicle fleet

    Directory of Open Access Journals (Sweden)

    Timothy J. Wallington

    2008-04-01

    Full Text Available Vehicles emit carbon dioxide (CO2, carbon monoxide (CO, nitrogen oxides (NOx, hydrocarbons (HC, particulate matter (PM, hydrofluorocarbon 134a (HFC-134a, methane (CH4, and nitrous oxide (N2O. An understanding of these emissions is needed in discussions of climate change and local air pollution issues. To facilitate such discussions an overview of past, present, and likely future emissions from light duty vehicles is presented. Emission control technologies have reduced the emissions of CO, VOCs, PM, HFC-134a, CH4, and N2O from modern vehicles to very low levels.

  14. 浅谈TCE供应格局变化对我国HFC-134a行业的影响%HFC-134a In China is Affected by the Change Supply Pattern of TCE

    Institute of Scientific and Technical Information of China (English)

    马文锐; 尹海飞

    2011-01-01

    随着全球经济形势的变化,先是金融危机冲击氯碱行业,国外TCE(三氯乙烯)装置纷纷减产或关停;再有国际氟化工公司战略转型,基础氟化工产品[1](HFC-134a、低端PTFE等)生产向发展中国家转移;后是各国政府纷纷出台政策刺激经济,制冷剂需求持续升温,而其生产原料之一TCE供应格局却发生了翻天覆地的变化,本文详细分析原料TCE对下游HFC-134a行业的深远影响,提出制冷剂行业针对TCE供应格局变化的应对建议。%Along with the changing of global economic,financial crisis impact chlor-alkali industry,foreign TCE(trichloroethylene) device reduce the production or shut down.International fluorine chemical company planned strategic transformation,production of based

  15. Estimated 2017 Refrigerant Emissions of 2,3,3,3-Tetrafluoropropene (HFC-1234yf) in the United States Resulting from Automobile Air Conditioning

    Science.gov (United States)

    In response to recent regulations and concern over climate change, the global automotive community is evaluating alternatives to the current refrigerant used in automobile air conditioning units, 1,1,1,2-tetrafluoroethane, HFC-134a. One potential alternative is 2,3,3,3-tetrafluor...

  16. Estimated 2017 Refrigerant Emissions of 2,3,3,3-Tetrafluoropropene (HFC-1234yf) in the United States Resulting from Automobile Air Conditioning

    Science.gov (United States)

    In response to recent regulations and concern over climate change, the global automotive community is evaluating alternatives to the current refrigerant used in automobile air conditioning units, 1,1,1,2-tetrafluoroethane, HFC-134a. One potential alternative is 2,3,3,3-tetrafluor...

  17. Diseño de una red urbana HFC para la distribución de servicios avanzados de telecomunicación.

    OpenAIRE

    2001-01-01

    Este traba}o presenta el diseño de la infraestructura básica correspondiente a una arquitectura de red híbrida fibra óptica-cable coaxial (HFC) para la distribución de contenidos telemáticos integrados por cable en pequeños núcleos

  18. Global and regional emissions estimates of 1,1-difluoroethane (HFC-152a, CH3CHF2 from in situ and air archive observations

    Directory of Open Access Journals (Sweden)

    P. G. Simmonds

    2015-08-01

    Full Text Available High frequency, ground-based, in situ measurements from eleven globally-distributed sites covering 1994–2014, combined with measurements of archived air samples dating from 1978 onward and atmospheric transport models, have been used to estimate the growth of 1,1-difluoroethane (HFC-152a, CH3CHF2 mole fractions in the atmosphere and the global emissions required to derive the observed growth. HFC-152a is a significant greenhouse gas but since it does not contain chlorine or bromine, HFC-152a makes no direct contribution to the destruction of stratospheric ozone and is therefore used as a substitute for the ozone depleting chlorofluorocarbons (CFCs and hydrochlorofluorocarbons (HCFCs. HFC-152a has exhibited substantial atmospheric growth since the first measurements reaching a maximum annualised global growth rate of 0.81 ± 0.05 ppt yr−1 in 2006, implying a substantial increase in emissions up to 2006. However, since 2007, the annualised rate of growth has slowed to 0.38 ± 0.04 ppt yr−1 in 2010 with a further decline to an average rate of change in 2013–2014 of −0.06 ± 0.05 ppt yr−1. The average Northern Hemisphere (NH mixing ratio in 1994 was 1.2 ppt rising to a mixing ratio of 10.2 ppt in December 2014. Average annual mixing ratios in the Southern Hemisphere (SH in 1994 and 2014 were 0.34 and 4.4 ppt, respectively. We estimate global emissions of HFC-152a have risen from 7.3 ± 5.6 Gg yr−1 in 1994 to a maximum of 54.4 ± 17.1 Gg yr−1 in 2011, declining to 52.5 ± 20.1 Gg yr−1 in 2014 or 7.2 ± 2.8 Tg-CO2 eq yr−1. Analysis of mixing ratio enhancements above regional background atmospheric levels suggests substantial emissions from North America, Asia and Europe. Global HFC emissions (so called "bottom up" emissions reported by the United Nations Framework Convention on Climate Change (UNFCCC are based on cumulative national emission data reported to the UNFCCC, which in turn are based on national consumption data. There

  19. Energetic assessment of HFC-blends as R 22 alternatives; Energetische Bewertung von FKW-Gemischen als R 22-Alternativen

    Energy Technology Data Exchange (ETDEWEB)

    Ahnefeld, G. [Inst. fuer Luft- und Kaeltetehnik gem.GmbH, Dresden (Germany); Vollmer, D. [Inst. fuer Luft- und Kaeltetehnik gem.GmbH, Dresden (Germany); Wobst, E. [Inst. fuer Luft- und Kaeltetehnik gem.GmbH, Dresden (Germany)

    1996-05-01

    Available with ILK is an HFC, HFC-blend test rig, which can be used for testing of refrigerant compressors as well as for industrial plant tests under nearly practical conditions. As compared with R 22, performance measurements of plants operated with the HFC-blends R 407C, R 407A, R 407B, R 404A and R 507 under constant external conditions (temperature difference 5 K between refrigerant/heat carrier, constant refrigerating capacity) showed losses up to 20% for the coefficient of performance. The highest deviations between theoretical cycle calculations and experimental results were obtained on R 407C and R 407A. One reason is an increased temperature glide of the condensing refrigerant caused by pressure drop and subcooling. Energetic benefits can be achieved through installation of an internal heat exchanger at blends with a higher R 125 content (R 407B, R 404A, R 507). (orig.) [Deutsch] Mit der FKW-, FKW-Gemisch-Experimentieranlage steht im ILK eine Versuchseinrichtung zur Verfuegung, die sowohl fuer Verdichterleistungsmessungen als auch fuer anlagentechnische Untersuchungen unter praxisnahen Bedingungen geeignet ist. Anlagenleistungsmessungen mit den zeotropen FKW-Gemischen R 407C, R 407A, R 407B und R 404A sowie dem azeotropen Gemisch R 507 haben bei konstanten aeusseren Bedingungen (Temperaturspreizung des Kaelte-/Waermetragers 5 K, konstante Kaelteleistung) Leistungszahleinbussen bis zu 20% im Vergleich zu R 22 ergeben. Bei R 407C und R 407A weichen die Werte besonders stark von theoretischen Vorausberechnungen (Kreisprozess) ab. Eine wesentliche Ursache ist die durch Druckverlust und Unterkuehlung vergroesserte Temperaturaenderung im Verfluessiger. Vom LORENZ-Prozess ist bekannt, dass zusaetzliche Verluste auftreten, wenn die Temperaturaenderung des zeotropen Kaeltemittelgemisches groesser als die Temperaturspreizung des aeusseren Stoffstromes ist. Auch eine wesentliche Flaechenvergroesserung fuehrt dann nur zu geringen Verbesserungen. Die Anwendung des

  20. HFC宽带接入网上行带宽分配策略的改进%Improving the Upstream Bandwidth Allocation Policy for the HFC Broadband Access Networks

    Institute of Scientific and Technical Information of China (English)

    宋军; 甘育裕; 吴资玉

    2003-01-01

    The request/transmit based upstream bandwidth resource allocation policy of DOCSIS introduces a trouble to the quality of the data service provided in the I-IFC networks. In this paper, the mechanism of the upstream data transrmitting and the process of data service transmitting in the HFC networks are described in detail, and the perfor- mance of the data service in HFC networks is analyzed. An advanced upstream bandwidth resource allocation policy is proposed to improve the quality of the data service in the HFC networks.

  1. [Roman Czaja. Die Anfänge preussischer Hansestädte im Lichte der historischen und archäologischen quellen : Danzig/Gdańsk, Elbing/Elbląg, Thorn/Toruń] / Dennis Hormuth

    Index Scriptorium Estoniae

    Hormuth, Dennis

    2013-01-01

    Arvustus : Roman Czaja. Die Anfänge preussischer Hansestädte im Lichte der historischen und archäologischen quellen : Danzig/Gdańsk, Elbing/Elbląg, Thorn/Toruń. In: Stadtgründung und Stadterweiterung. Beiträge von Archäologie und Stadtgeschichtsforschung. (=Beiträge zur Geschichte der Städte Mitteleuropas XXII). LInz, 2011. S. 59-74

  2. [Roman Czaja. Die Anfänge preussischer Hansestädte im Lichte der historischen und archäologischen quellen : Danzig/Gdańsk, Elbing/Elbląg, Thorn/Toruń] / Dennis Hormuth

    Index Scriptorium Estoniae

    Hormuth, Dennis

    2013-01-01

    Arvustus : Roman Czaja. Die Anfänge preussischer Hansestädte im Lichte der historischen und archäologischen quellen : Danzig/Gdańsk, Elbing/Elbląg, Thorn/Toruń. In: Stadtgründung und Stadterweiterung. Beiträge von Archäologie und Stadtgeschichtsforschung. (=Beiträge zur Geschichte der Städte Mitteleuropas XXII). LInz, 2011. S. 59-74

  3. FC网络工程图纸的绘制%HFC Network Engineering Drawings of Drawing Method

    Institute of Scientific and Technical Information of China (English)

    先守东

    2012-01-01

    Engineering drawings in HFC network construction has the very important role. This article from the following several aspects of the engineering drawings of rendering techniques: How to get the reference map; The importance of field survey; The benefits of scale conversion; Drawing method and forms of engineering drawing.%工程图纸在HFC网络建设中具有很重要的作用,从以下几个方面阐述工程图纸的绘制技巧:如何获取用于工程图纸设计的参照图;实地调查的重要性;比例尺转换的好处;工程图纸的绘制方法及形式。

  4. Random test of R22 and HFC leakage in cooling installations; Steekproefonderzoek R22 en HFK lekkage koelinstallaties

    Energy Technology Data Exchange (ETDEWEB)

    Pennartz, F.; Van den Bovenkamp, M. [KWA Bedrijfsadviseurs, Amersfoort (Netherlands)

    2013-02-15

    KWA Business Consultants has conducted a random test survey in the dairy industry, meat industry and a peer group in other food sectors. The main goal was to obtain data on the size and trends of R22 and HFC emissions in the period 2007-2010. The survey is carried out by collecting the data of refilling refrigeration installations that have been registered by the refrigeration contractors. In total 1984 installations of 193 companies participated in the random test [Dutch] Begin 2012 is in opdracht van Agentschap NL onderzoek uitgevoerd naar lekkages van R22 en HFK koudemiddelen uit koelinstallaties in de sectoren zuivel, vlees en overige gerelateerde sectoren in de voedingsmiddelenindustrie. Het onderzoek had de vorm van een steekproef. Er hebben 193 bedrijven deelgenomen; 1984 koelinstallaties zijn onderzocht. Het gemiddelde lekpercentages is 7. De lekkages zijn afkomstig van 10 procent van de installaties uit de onderzoeksgroep.

  5. Final Technical Report HFC Concrete: A Low­Energy, Carbon-Dioxide­Negative Solution for reducing Industrial Greenhouse Gas Emissions

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Larry McCandlish, Principal Investigator; Dr. Richard Riman, Co-Principal Investigator

    2012-05-14

    Solidia/CCSM received funding for further research and development of its Low Temperature Solidification Process (LTS), which is used to create hydrate-free concrete (HFC). LTS/HFC is a technology/materials platform that offers wide applicability in the built infrastructure. Most importantly, it provides a means of making concrete without Portland cement. Cement and concrete production is a major consumer of energy and source of industrial greenhouse gas (GHG) emissions. The primary goal of this project was to develop and commercialize a novel material, HFC, which by replacing traditional concrete and cement, reduces both energy use and GHG emissions in the built infrastructure. Traditional concrete uses Portland Cement (PC) as a binder. PC production involves calcination of limestone at {approx}1450 C, which releases significant amounts of CO{sub 2} gas to the atmosphere and consumes a large amount of energy due to the high temperature required. In contrast, HFC is a carbonate-based hydrate-free concrete (HFC) that consumes CO{sub 2} gas in its production. HFC is made by reaction of silicate minerals with CO{sub 2} at temperatures below 100 C, more than an order-of-magnitude below the temperature required to make PC. Because of this significant difference in temperature, it is estimated that we will be able to reduce energy use in the cement and concrete industry by up to 30 trillion Btu by 2020. Because of the insulating properties of HFC, we believe we will also be able to significantly reduce energy use in the Building sector, though the extent of this saving is not yet quantified. It is estimated that production of a tonne of PC-based concrete requires about 6.2 million Btu of energy and produces over 1 tonne of CO{sub 2} emissions (Choate, 2003). These can be reduced to 1.9 million Btu and 0.025 tonnes of CO{sub 2} emissions per tonne of HFC (with overall CO{sub 2}-negativity possible by increasing carbonation yield). In this way, by replacing PC

  6. EVALUASI PENGELOLAAN REFRIGERAN CFC, DAN HFC DENGAN MESIN 3R DAN UJI UNJUK KERJA MESIN PENDINGIN STUDI KASUS PADA BENGKEL AC MOBIL DI DENPASAR - BALI

    OpenAIRE

    I MADE RASTA; I.W. Kasa; I Gede Mahardika

    2015-01-01

    CFC refrigerant has been known to be one of causes of ozone layer diminishing and HFC is one of green house gases contributing to global warming through the leak and synthetic refrigerant waste to environment. As a response to the ozone layer diminishment on stratosphere, UNEP, in 1981, through a negotiating process of international stages of development reserve the ozone layer through Wina Convention legalized in March 1985. It was then followed up with Montreal Protocol in September 1987 co...

  7. (Vapour + liquid) equilibria of the {l_brace}1,1,1-trifluoroethane (HFC-143a) + isobutene{r_brace} system

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Yongju; Im, Jihoon [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Shinlim-dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Kim, Hwayong [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Shinlim-dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of)], E-mail: hwayongk@snu.ac.kr

    2008-05-15

    Isothermal (vapour + liquid) equilibrium data were measured for the {l_brace}1,1,1-trifluoroethane (HFC-143a) + isobutene{r_brace} as an alternative refrigerant in the temperature range from (273.15 to 348.15) K at 15 K intervals. A circulating-type apparatus with on-line gas chromatography was used in these experiments. The experimental data were correlated well by Peng-Robinson equation of state using the Wong-Sandler mixing rules.

  8. Primer registro e histología básica del anfípodo terrestre Talitroides topitotum (Amphipoda: Talitridae), introducido en las zonas montañosas de Heredia, Costa Rica

    OpenAIRE

    Alfaro Montoya, Jorge; Umaña Castro, Rodolfo

    2013-01-01

    Este estudio documenta por primera vez la introducción del anfípodo terrestre, Talitroides topitotum (Talitridae) en diversas zonas montañosas de los cantones de San Rafael y Barva, Heredia, Costa Rica, con predominio de juveniles y hembras adultas con y sin huevos. La especie es de origen asiático y podría haber sido introducida asociada con plantas exóticas. Se describen aspectos básicos de la histología de la especie, incluyendo la estructura celular de los principales órganos: corazón, in...

  9. Tracing the origins of the Costa Rican (neo) liberalism. The influence of the Asociación Nacional de Fomento Económico (ANFE) as an intellectual center 1970-1990

    OpenAIRE

    Marchena Sanabria, Jorge

    2016-01-01

    This article analyzes the political influence of the Asociación Nacional de Fomento Económico (ANFE), a self-defined defender of liberalism and seeks the promotion of the business and the contraction of Welfare State, in the decade of 1980. The main objective is to point out the consolidation of neoliberal thought in Costa Rica, highlight some of their ideas and describe its political role. The role played by his writings in the press and conferences sponsored by USAID offered in the 1980’s a...

  10. Global and regional emissions estimates of 1,1-difluoroethane (HFC-152a, CH3CHF2 from in situ and air archive observations

    Directory of Open Access Journals (Sweden)

    P. G. Simmonds

    2016-01-01

    Full Text Available High frequency, in situ observations from 11 globally distributed sites for the period 1994–2014 and archived air measurements dating from 1978 onward have been used to determine the global growth rate of 1,1-difluoroethane (HFC-152a, CH3CHF2. These observations have been combined with a range of atmospheric transport models to derive global emission estimates in a top-down approach. HFC-152a is a greenhouse gas with a short atmospheric lifetime of about 1.5 years. Since it does not contain chlorine or bromine, HFC-152a makes no direct contribution to the destruction of stratospheric ozone and is therefore used as a substitute for the ozone depleting chlorofluorocarbons (CFCs and hydrochlorofluorocarbons (HCFCs. The concentration of HFC-152a has grown substantially since the first direct measurements in 1994, reaching a maximum annual global growth rate of 0.84 ± 0.05 ppt yr−1 in 2006, implying a substantial increase in emissions up to 2006. However, since 2007, the annual rate of growth has slowed to 0.38 ± 0.04 ppt yr−1 in 2010 with a further decline to an annual average rate of growth in 2013–2014 of −0.06 ± 0.05 ppt yr−1. The annual average Northern Hemisphere (NH mole fraction in 1994 was 1.2 ppt rising to an annual average mole fraction of 10.1 ppt in 2014. Average annual mole fractions in the Southern Hemisphere (SH in 1998 and 2014 were 0.84 and 4.5 ppt, respectively. We estimate global emissions of HFC-152a have risen from 7.3 ± 5.6 Gg yr−1 in 1994 to a maximum of 54.4 ± 17.1 Gg yr−1 in 2011, declining to 52.5 ± 20.1 Gg yr−1 in 2014 or 7.2 ± 2.8 Tg-CO2 eq yr−1. Analysis of mole fraction enhancements above regional background atmospheric levels suggests substantial emissions from North America, Asia, and Europe. Global HFC emissions (so called “bottom up” emissions reported by the United Nations Framework Convention on Climate Change (UNFCCC

  11. Notas sobre predação em uma taxocenose de anfíbios anuros no sudeste do Brasil Predation notes in an anuran amphibians assemblage from southeastern Brazil

    Directory of Open Access Journals (Sweden)

    José P. Pombal Jr

    2007-01-01

    Full Text Available Anfíbios anuros são predados por todos os grupos de vertebrados e muitos invertebrados. Todavia os estudos sobre predação em anfíbios anuros ainda são esparsos e anedóticos. Neste estudo são fornecidas informações sobre predação de anuros de uma assembléia no sudeste do Brasil. Invertebrados (aranhas e barata d’agua, a rã Leptodactylus cf. ocellatus e cinco espécies serpentes (quatro Colubridae e um Viperidae predaram espécies ou indivíduos de pequeno porte.Anuran amphibians are preyer by all vertebrate groups and several invertebrates. However, predation studies on amphibians are still occasional and anecdotic. Herein, informations on predation of an anuran assemblage of southeastern Brazil are provided. Invertebrates (spiders and water bugs, the frog Leptodactylus cf. ocellatus, and five snake species (four Colubridae and one Viperidae preyer on small individuals or small anuran species.

  12. EVALUASI PENGELOLAAN REFRIGERAN CFC, DAN HFC DENGAN MESIN 3R DAN UJI UNJUK KERJA MESIN PENDINGIN STUDI KASUS PADA BENGKEL AC MOBIL DI DENPASAR - BALI

    Directory of Open Access Journals (Sweden)

    I MADE RASTA

    2015-06-01

    Full Text Available CFC refrigerant has been known to be one of causes of ozone layer diminishing and HFC is one of green house gases contributing to global warming through the leak and synthetic refrigerant waste to environment. As a response to the ozone layer diminishment on stratosphere, UNEP, in 1981, through a negotiating process of international stages of development reserve the ozone layer through Wina Convention legalized in March 1985. It was then followed up with Montreal Protocol in September 1987 consisting supervision rules on producing, consuming, and treading ozone damaging materials. The government of Indonesia had ratified the convention through President Decree Number 23 Year 1999. The ozone layer reservation program implementation in Indonesia is facilitated by KLH. Governor of Bali issued Decree Number 523/04-B/HK/2010 on membership restructuring of ozone layer reservation and ozone damaging materials control team work in province of Bali. This research was done in 27 car AC service companies or workshop, which received grant of 3R engine in Denpasar, Bali. The research was dominantly focused on monitoring and evaluation, that is how car AC service company or workshop manage CFC/ R-12 and HFC/R-134a refrigerant at service time using 3R engine that refrigerant does not escape to atmostphere. Cooling machine work procedure test (COP was conducted in laboratory. Research result showed that car AC service company or workshop could manage CFC/ R-12 and HFC /R-l 34a eefctively ( 88,3%. The cooling engine work procedure using CFC /R-12 as the result of 3R engine recovery and recycel resulted in 2,435 while pure CFC/R-12 resulted in 2,54. There were differences in cooling engine work procedure to the use of pure CFC/R-12 refrigerant with that resulted by 3R engine with avarage difference 0,089 or 3,53%.

  13. Diseño de una red urbana HFC para la distribución de servicios avanzados de telecomunicación

    OpenAIRE

    2001-01-01

    Este traba}o presenta el diseño de la infraestructura básica correspondiente a una arquitectura de red híbrida fibra óptica-cable coaxial (HFC) para la distribución de contenidos telemáticos integrados por cable en pequeños núcleos urbanos. En este contexto el problema de Steiner modela adecuadamente la situación. Finalmente se presenta una batería de heurísticas que permite afrontar con éxito este tipo de diseños.

  14. (Vapour + liquid) equilibria of the {l_brace}1,1-difluoroethane (HFC-152a) + n-butane (HC-600){r_brace} system

    Energy Technology Data Exchange (ETDEWEB)

    Im, Jihoon [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Shinlim-dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Lee, Gangwon [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Shinlim-dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Lee, Yong-Jin [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Shinlim-dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Kim, Hwayong [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Shinlim-dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of) ]. E-mail: hwayongk@snu.ac.kr

    2007-08-15

    Binary (vapour + liquid) equilibrium data were obtained for the {l_brace}1,1-difluoroethane (HFC-152a) + n-butane (HC-600){r_brace} system at temperatures from 313.15 K to 363.15 K. These experiments were carried out with a circulating-type apparatus with on-line gas chromatography. The experimental data were correlated well by Peng-Robinson equation of state using the Wong-Sandler mixing rules. This system shows positive azeotropic phase behaviour.

  15. Dynamic Viscosity for HFC-134a + Polyether Mixtures up to 373.15 K and 140 MPa at Low Polyether Concentration. Measurements and Modeling

    CERN Document Server

    Comuñas, Maria J P; Boned, Christian; Fernandez, Josefa

    2008-01-01

    This paper reports viscosity data for mixtures containing a refrigerant (HFC-134a) and a lubricant (triethylene glycol dimethyether, TriEGDME, or tetraethylene glycol dimethyl ether, TEGDME), at 12% of TriEGDME or 14% mass fraction of TEGDME. The measurements (140 data points) were obtained at various pressures (between 10 and 140 MPa) in the monophasic liquid state from 293.15 to 373.15 K. Because HFC-134a and the polyethers are not in the same single phase at normal pressure and temperature (the refrigerant is a gas, whereas the polyethers are liquids), accurate measurements of their mixtures require specific procedures for preparation of the samples and filling of the apparatus. A specially designed isobaric-transfer falling-body viscometer is used in this work. The viscosities of the mixtures are, on average, 40% higher than that of the pure refrigerant, and this increase is more noticeable at low temperatures. The experimental viscosities have been used to check the predictive and correlation ability of ...

  16. Condensation of downward-flowing zeotropic mixture HCFC-123/HFC-134a on a staggered bundle of horizontal low-finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H.; Takamatsu, H.; Takata, N. [Kyushu Univ., Kasuga, Fukuoka (Japan). Inst. of Advanced Material Study

    1999-05-01

    Experiments were conducted to obtain row-by-row heat transfer data during condensation of downward-flowing zeotropic refrigerant mixture HCFC-123/HFC-134a on a 3 x 15 (columns x rows) staggered bundle of horizontal low-finned tubes. The vapor temperature and the HFC-134a mass fraction at the tube bundle inlet were maintained at about 50 C and 9%, respectively. The refrigerant mass velocity ranged from 9 to 34 kg/m{sup 2} s, and the condensation temperature difference from 3 to 12 K. The measured distribution of the vapor mass fraction in the tube bundle agreed fairly well with that of the equilibrium vapor mass fraction. The vapor phase mass transfer coefficient was obtained from the heat transfer data by subtracting the thermal resistance of the condensate film. The heat transfer coefficient and the mass transfer coefficient decreased significantly with decreasing mass velocity. These values first increased with the row number up to the third (or second) row, then decreased monotonically with further increasing row number, and then increased again at the last row. The mass transfer coefficient increased with condensation temperature difference, which was due to the effect of suction associated with condensation. On the basis of the analogy between heat and mass transfer, a dimensionless correlation of the mass transfer coefficient for the 4th to 14th rows was developed.

  17. Condensation of Downward-Flowing Zeotropic Mixture HCFC-123/HFC-134a on a Staggered Bundle of Horizontal Low-Finned Tubes

    Science.gov (United States)

    Honda, Hiroshi; Takamatsu, Hiroshi; Takata, Nobuo

    Expenmentswere conducted to obtain row-by-row heat transfer data during condensation of downward-flowing zeotropic refrigerant mixture HCFC-123/HFC-134 a on a staggered bundle of horizontal low-finned tubes. The vapor temperature and the HFC-134a m ass fraction at the tube bundle inlet were maintained at about 50°C and 14% respectively. The refrigerant mass velocity ranged from 9 to 33 kg/m2s, and the condensation temperature difference from 2 to 12K. Four kinds of low-finned tubes with different fin geometry were tested. The highest heat transfer coefficient was obtained with a tube which showed the highest performance for HCFC-123. However, the effect of fin geometry was much smaller for the mixture than for HCFC-123. The heat transfer coefficient and the vapor-phase mass transfer coefficient decreased significantly with decreasing mass velocity. On the other hand, the mass transfer coefficient increased with condensation temperature difference. This was due to the effect of suction associated with condensation. On the basis of the analogy between heat and mass transfer, a dimensionless correlation of the mass transfer coefficient was developed for each tube.

  18. Energy savings with the effect of magnetic field using R290/600a mixture as substitute for CFC12 and HFC134a

    Directory of Open Access Journals (Sweden)

    Mani Kolandavel

    2008-01-01

    Full Text Available This paper presents an experimental study on the replacement of CFC12 and HFC134a by the new R290/R600a refrigerant mixture as drop-in replacement refrigerant with and without the effect of magnetic field. Without any modification to the system components drop-in experimental tests were performed on a vapour compression refrigeration system with a reciprocating compressor, which was originally designed to operate with CFC12.The test results with no magnets showed that the refrigerant R290/R600a had 19.9-50.1% higher refrigerating capacity than R12 and 28.6-87.2% than R134a. The mixture R290/R600a consumed 6.8- -17.4% more energy than R12. The coefficient of performance of R290/R600a mixture increases from 3.9-25.1% than R12 at lower evaporating temperatures and 11.8-17.6% at higher evaporating temperatures. The effect of magnetic field force reduced the compressor energy consumption by 1.5-2.5% than with no magnets. The coefficient of performance of the system was higher in the range 1.5-2.4% with the effect of magnetic field force. The R290/600a (68/32 by wt.% mixture can be considered as an excellent alternative refrigerant for CFC12 and HFC134a systems.

  19. Comparative analysis of CO2-based transcritical Rankine cycle and HFC245fa-based subcritical organic Rankine cycle using low-temperature geothermal source

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A detailed thermodynamic and techno-economic comparison is presented for a CO2-based transcritical Rankine cycle and a subcritical organic Rankine cycle (ORC) using HFC245fa (1,1,1,3,3-pentafluoro-propane) as the working fluid driven by the low-temperature geothermal source,in order to determine the configuration that presents the maximum net power output with a minimum investment.The evaluations of both Rankine cycles have been performed based on equal thermodynamic mean heat rejection temperature by varying certain system operating parameters to achieve each Rankine cycle’s optimum design at various geothermal source temperature levels ranging from 80oC to 120oC.The results obtained show that the optimum ther-modynamic mean heat injection temperatures of both Rankine cycles are distributed in the scope of 55% to 65% of a given geothermal source temperature level,and that the CO2-based transcritical Rankine cycle presents 3% to 7% higher net power output,84% reduction of turbine inlet volume flow rate,47% reduction of expansion ratio and 1.68 times higher total heat transfer capacity compared with the HFC245fa-based subcritical ORC.It is also indicated that using the CO2-based transcritical system can reduce the dimension of turbine design.However,it requires larger heat transfer areas with higher strength heat exchanger materials because of the higher system pressure.

  20. Effects of V-type ducts on condensation heat transfer of HFC245fa on horizontal tube bundles%V型导液槽对HFC245fa水平管束外冷凝换热影响

    Institute of Scientific and Technical Information of China (English)

    马志先; 张吉礼; 孙德兴

    2011-01-01

    试验研究了HFC245fa在水平光管与强化管管束外的冷凝换热特性,提出在管束中加装V型导液槽来消除管束效应的方法,并通过试验研究了V型导液槽对管束冷凝换热特性的影响.试验管束由4列排深为5排的列管构成,带导液槽管束的前4排管下方加装了两段长度为450 mm的导液槽;试验换热管公称外径为19.05 mm、换热长度为1000 mm.试验中,以Wilson描点法获得强化换热管水侧对流传热系数,以对比试验方法研究了V型导液槽对水平管束外冷凝换热性能的影响.结果表明:传统的管束效应模型仅在较小的热通量范围适用;凝液在管间的迁移形态与流态随管上作用凝液量的系列变化是导致管束效应变化的主要因素;加装导液槽可有效控制凝液在管间的迁移,控制管束效应;加装导液槽使光管单管冷凝传热能力下降10%左右,使光管管束总体换热能力提升4.5%~9.5%;加装导液槽对强化管单管冷凝换热性能的影响比对光管影响强近4倍.本文研究成果对引入导液槽开发新型高效卧式冷凝管束具有指导意义.%In a horizontal condensation tube-bundle, the inundation effect, resulted from local condensation film and falling condensate from upper tube rows, may reduce the condensation heat transfer coefficient (CHTC) considerably. This paper presents an experimental study on condensation heat transfer characteristic of HFC245fa on horizontal tube bundles. A scheme was proposed to reduce the tube row effect resulted from falling condensate with V-type ducts, and the effect of the duct on CHTC of the tube bundles was investigated experimentally. The tube bundle consisted of 4 columns, each with 5 tubes, with smooth tubes and enhanced tubes, separately. Two columns out of the four were equipped with the duct. The equivalent outside diameter and effective length for heat transfer of tubes were 19.05 mm and 1000 mm respectively. In the experiment, water

  1. Technical and economic evaluation of emission abatement options of HFC{sub s}, PFC{sub s} and SF{sub 6}. The case of Finland; HFC- ja PFC-yhdisteiden sekae SF6:n paeaestoejen tekniset vaehentaemiskeinot ja niiden kustannukset Suomessa

    Energy Technology Data Exchange (ETDEWEB)

    Oinonen, T.; Soimakallio, S. [VTT Energy, Espoo (Finland). Energy Systems

    2001-07-01

    Emissions of the so called new greenhouse gases - HFC{sub s}, PFC{sub s} and SF6 - are expected to grow globally in the near future. Sources, magnitudes and projections of future emissions differ significantly between countries, mainly due to structural differences between countries' industries, as well as the rate and phase of the substitution of ozone depleting substances by HFC{sub s} and PFC{sub s}. This study focuses on Finnish emissions of the new greenhouse gases, the projected growth in emissions, and the resulting need to reduce these emissions. Currently, emissions of new greenhouse gases amount to some 0.5 Mt of CO{sub 2}-eq. in Finland. Emissions are expected to quadruple by 2010 and to be five-fold by 2020, at which time they represent a much larger share of Finnish emissions of Kyoto greenhouse gases than presently. The substitution of ozone depleting substances by HFC-refrigerants was indentified as a major driver behind the expected growth of emissions. After the first Kyoto commitment period, emissions of HFC-refrigerants were projected to contribute some 90% of the total emissions of new greehouse gases in Finland. The application of emission reduction technologies to an existing equipment base is usually more problematic and less effective than applying these technologies to new equipment. For this reason, the emission reduction potential is conditional on schedule of introducing abatement measures. In the calculations of this study, most of the abatement measures were introduced in 2002. The measures considered consisted mainly of two kinds of technical reduction options: i) alternative gases and technologies and ii) leakage reduction (containment). Measures focusing on application of altenatives were significantly more expensive compared to leakage reduction. Average abatement costs of leakage reduction, weighted by potential emission reductions, were estimated as 80 FIM/t CO{sub 2}-eq. during the first Kyoto commitment period and 60 FIM

  2. High-pressure structure prediction of Hf-C system and first-principle simulation of their electronic prop erties%Hf-C体系的高压结构预测及电子性质第一性原理模拟∗

    Institute of Scientific and Technical Information of China (English)

    彭军辉; 曾庆丰; 谢聪伟; 朱开金; 谭俊华

    2015-01-01

    Hafnium carbides (Hf-C system), known as ultra-high temperature ceramics, have attracted growing attention because of their unique features. In this paper, we carry out researches on the stable crystal structures in the Hf-C system at high pressures, using a variable-composition ab initio evolutionary algorithm implemented in the USPEX code. In addition to the ambient-pressure structures HfC (F m¯3m), there are two new compounds Hf3C2 and Hf6C5 and two high-pressure structures of HfC. When pressures are lower than 100 GPa, no new structures are found other than those at ambient pressure, and Hf3C2 and Hf6C5 become metastable at 20 GPa and 100 GPa, respectively. At 200 GPa, a new compound Hf2C is found, and the stable structure HfC has changed from F m¯3m to C2/m. At 300 GPa, another new compound HfC2 is found. At 400 GPa, the stable structure of HfC has changed again to the space group P nma. And at 500 GPa, the stable structures are Hf2C, HfC2 and HfC (P nma), no new structures are found except those at 400 GPa. The composition-pressure phase diagram that shows the pressure range of stable structures in Hf-C system is simulated by calculation of their enthalpies. When the pressures are lower than 15.5 GPa and 37.7 GPa, Hf3C2 and Hf6C5 are stable, respectively, and their space groups are both of C2/m. And Hf2C and HfC2, with space group I4/m and Immm, respectively become stable structures when the pressure is higher than 102.5 GPa and 215.5 GPa, respectively. The phase-transition route of HfC is F m¯3m → C2/m → P nma, and the two phase-transition pressures are 185.5 GPa and 322 GPa, respectively, which are different from the conclusion of Zhao. Then we will show and discuss the newly predicted high-pressure structures and their crystallographic data, such as volume, lattice constants and atom positions. The crystal structures of HfC are described in the literature. The structure of Hf2C contains 12 atoms in the conventional cell, and carbon atoms lie at the

  3. A Positive and Negative Sequence Component Separation Method for Grid Voltage Based on the Phase Locked Loop With an Adaptive Notch Filter%基于ANF-PLL的电网电压基波正负序分离方法

    Institute of Scientific and Technical Information of China (English)

    杜雄; 郭宏达; 孙鹏菊; 周雒维

    2013-01-01

    为了满足并网变流器在电网电压不对称情况下的控制需求,需要快速准确地提取出基波正负序分量的幅值和相位。在电网电压不对称时,负序分量会在同步参考坐标系锁相环(phase locked loop based on synchronization reference frame,SRF-PLL)的 dq 轴分量中产生2倍工频波动,影响基波分量和相位的提取结果。该文通过将自适应陷波器(adaptive notch filter,ANF)加入到同步参考坐标系锁相环的结构中,提出了一种能够实现正负序分量分离的自适应陷波器锁相环(phase locked loop with ANF,ANF-PLL)方法。该方法利用ANF陷波器的2个相互正交的输出量分别抵消电网电压dq轴分量中由于负序分量造成的2倍工频波动,以此消除了电网电压不对称对同步信号检测的影响,并且可以同时提取出基波负序分量的幅值和相位。与其它方法相比,该方法无需进行正负序解耦或瞬时对称分量分离,在单同步参考坐标系下实现了基波正负序分量的分离提取,结构更加简单,减少了计算量。实验结果表明,文中提出的方法能够在电网电压不对称与频率变化的情况下准确提取出基波正负序分量的幅值与相位,并且具有良好的动态性能。%In order to meet the unbalanced control demand of the grid-connected power converters, the fast and accurate extraction of the fundamental positive and negative sequence components of the grid voltage is necessary. Under unbalanced grid voltage condition, the negative sequence component appears as the double frequency oscillations in the d-q axes components of the phase locked loop based on synchronization reference frame (SRF-PLL), which affects the extraction of the fundamental components and the phase angle signal. By applying the adaptive notch filter (ANF) to the structure of SRF-PLL, this paper proposed a grid voltage synchronization method based on phase locked loop with

  4. Nucleate pool boiling heat transfer coefficients of pure HFC134a, H&c, HC600a and their binary and ternary mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Zhaohu; Gong, Maoqiong; Li, Zhijian; Wu, Jianfeng [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing (China)

    2007-01-15

    An experimental test rig for study on the pooling-boiling heat transfer performance of pure and mixed refrigerants were designed and established. With this test system, the heat transfer coefficients (HTCs) of the nucleate boiling on a smooth flat surface were measured for pure fluids of HFC134a, HC290, HC600a and their binary and ternary mixtures. Extensive experimental measures were made for those pure and mixed refrigerants at different heat fluxes from 10kWm{sup -2} to 300kWm{sup -2} and different pressures from 0.2 to 0.6MPa. Comprehensive measured data are presented in this paper. From experimental results, these binary mixtures and ternary mixtures show different heat transfer features according to their vapor-liquid phase equilibria behaviors. New heat transfer correlations were regressed from the measured data with average deviations within +/-15% for pure refrigerants and within +/-20% for mixtures. (author)

  5. High-pressure viscosity behavior of x 1,1,1,2-tetrafluoroethane (HFC-134a)+(1-x) triethylene glycol dimethylether (TriEGDME) mixtures: Measurements and modeling

    DEFF Research Database (Denmark)

    Monsalvo, Matias Alfonso; Baylaucq, A.; Cisneros, Sergio;

    2006-01-01

    In this work new dynamic viscosity measurements for binary mixtures containing a refrigerant (HFC-134a, CF3CH2F) and a lubricant (TriEGDME, CH3O(CH2OCH2)(3)CH3) are reported. The measurements were carried out at temperatures between 293.15 and 373.15 K and pressures from 10 to 100 MPa, for two mo...... with a physical and theoretical background, such as the hard-sphere scheme, the free-volume model, and the friction theory....... for this binary system have been used to test the ability of several viscosity models having different origins and theoretical backgrounds. The considered models range from simple mixing rules, through empirical correlations, such as the self-referencing model and the LBC model, to recent approaches...

  6. A Model for the Oxidation of ZrB2, HfB2 and TiB2 (Postprint)

    Science.gov (United States)

    2007-03-01

    electronic conductivity obey the same dependencies as Eqs. ( A4a ) and (A4b). Patterson [27] has presented an evaluation of the ionic transference number... A4a ) and (A4b), the functions can be applied to nearly pure ZrO2, e.g. containing 150 ppm divalent impurity concentration. From Patterson et al. [28

  7. On-site study of HCFC-22 substitution for HFC non-azeotropic blends (R417A, R422D) on a water chiller of a centralized HVAC system

    Energy Technology Data Exchange (ETDEWEB)

    Torrella, E.; Larumbe, J.A. [Polytechnic University of Valencia, Dep. of Applied Thermodynamics, Camino de Vera 14, E-46022 Valencia (Spain); Cabello, R.; Sanchez, D.; Llopis, R. [Jaume I University, Dep. of Mechanical Engineering and Construction, Campus de Riu Sec s/n, E-12071 Castellon (Spain)

    2010-09-15

    The European Regulation no 2037/2000 has banned manufacturing HCFC refrigerants from January 1st 2010, although its use is allowed up to 2015 if the fluids come from a recycling process. This situation creates the need for developing new working fluids to replace the HCFC in the refrigeration plants now in operation. Among all the HCFCs the R22 is the most widely used in a wide range of applications, especially in air conditioning. This work presents an on-site experimental study of the R22 replacement by two possible substitutes, the HFC-417A and the HFC-422D, in a water chiller in which the energy performance was evaluated. This chiller is part of the centralized HVAC system of a lecture room building at the Jaume I University of Castellon, Spain. This communication compares and analyses main operation parameters of the chiller when operating with each refrigerant in real conditions. (author)

  8. Numerical modeling of the thermal-hydraulic behavior of wire-on-tube condensers operating with HFC-134a using homogeneous equilibrium model: evaluation of some void fraction correlations

    Science.gov (United States)

    Guzella, Matheus dos Santos; Cabezas-Gómez, Luben; da Silva, José Antônio; Maia, Cristiana Brasil; Hanriot, Sérgio de Morais

    2016-02-01

    This study presents a numerical evaluation of the influence of some void fraction correlations over the thermal-hydraulic behavior of wire-on-tube condensers operating with HFC-134a. The numerical model is based on finite volume method considering the homogeneous equilibrium model. Empirical correlations are applied to provide closure relations. Results show that the choice of void fraction correlation influences the refrigerant charge and pressure drop calculations, while no influences the heat transfer rate.

  9. 在HFC网上使用EPON技术是实现三网融合的最佳方案%In HFC Using FPON Technology is to Realize Online the Convergence of the Optimal Scheme

    Institute of Scientific and Technical Information of China (English)

    高丽

    2011-01-01

    在电信网、广播电视网和互联网三网逐渐融合总趋势下,有线电视HFC网络实现高宽带、高速率、多业务的双向改造问题是一个十分重要而紧迫的任务。通过HFC网络的分析,对EPON的探讨,提出了在HFC升级改造时,搭建EPON无源光网络的必要性和可行性。%In the network and broadcast networks and the Internet three nets fuses gradually under the general trend, CATV HFC network to realize high broadband, high rate, many business problem is a two -way transformation is very important and urgent task. Through the analysis of HFC network, the paper, the author puts forward the EPON in HFC upgraded, build EPON passive optical network of necessity and feasibility.

  10. Contribuição para o conhecimento das comunidades anfíbias no sul de Portugal Contributions to the knowledge of the amphibian communities in the South of Portugal

    Directory of Open Access Journals (Sweden)

    Marízia Menezes Dias Pereira

    2008-09-01

    Full Text Available As comunidades anfíbias pioneiras da bacia hidrográfica do Rio Sado (Setor Mariânico-Monchiquense, Subprovíncia Luso-Extremadurense e Setor Ribatagano-Sadense, Subprovíncia Sadense-Divisório Portuguesa foram objeto do presente estudo. Destacando-se a composição florística de cada fitocenose, bem como os dados referentes à sua ecologia, corologia e sintaxonomia, são apresentadas as principais comunidades vegetais anfíbias identificadas: Junco capitati-Isoetetum hystricis Braun-Blanquet 1936, Junco pygmaei-Isoetetum velati Rivas Goday 1956, Periballio laevis-Illecebretum verticillati Rivas Goday 1954, Loto subbiflori-Chaetopogonetum fasciculati Rivas-Martínez & Costa in Rivas-Martínez, Costa, Castroviejo & E. Valdés 1980, Hyperico elodis-Rhynchosporetum rugosae Neto, Capelo, J.C. Costa & Lousã in Neto 1997, Anagallido tenellae-Juncetum bulbosi Braun-Blanquet 1967, Utriculario exoletae-Sphagnetum auriculati Neto, Capelo, J.C. Costa & Lousã 1996 e Cirsio palustris-Juncetum rugosi Neto, Capelo, J.C. Costa & Lousã 1996. Este estudo mostrou que essas comunidades vegetais são, em sua maioria, relictos, com áreas de distribuição restritas e encontram-se fortemente pressionadas pela crescente ação antrópica e pelas alterações climáticas. Embora com características claramente atlânticas, foram sendo invadidas por espécies mediterrânicas, cujo domínio foi progressivamente aumentando desde o período Atlântico (7800-5700 B.P., durante o qual se verificou o seu ótimo.The pioneer amphibian communities of the Sado river basin (Marianic-Monchiquensean Sector, Lusitan-Extremadurean and Subprovince Ribatagan-Sadensean Sector, Sadensean-Divinding Portuguese Subprovince were subject of the present study. The main plant communities were identified (Junco capitati-Isoetetum hystricis Braun-Blanquet 1936, Junco pygmaei-Isoetetum velati Rivas Goday 1956, Periballio laevis-Illecebretum verticillati Rivas Goday 1954, Loto subbiflori

  11. Research on Fault Diagnosis of HFC Upstream Channel Based on ANN%基于神经网络的HFC上行信道故障诊断研究

    Institute of Scientific and Technical Information of China (English)

    张力; 朱琳; 马永涛; 刘开华; 陈韬

    2011-01-01

    In order to improve the network reliability and efficiency of network maintenance, it is important to search on how to determine noise and interference types quickly and accurately based on data of actual HFC network upstream channel and then assist to find out the cause of network malfunction. BP neural network malfunction diagnosis model of HFC upstream channel is established based on LM algorithm using Matlab. The networks are trained by actual HFC upstream channel data. It is proved by simulation that the method of application of LM neural network algorithm for malfunction diagnosis has some referenced and practical value and the accuracy rate of diagnose is more than 85%.%为了提高HFC网络的可靠性和网络维护的效率,研究如何从实际的HFC网络上行信道数据中快速、准确地判断出信道中噪声和干扰的类型,进而协助查找引发故障的原因具有重大意义.利用Matlab建立了基于LM算法的HFC上行信道故障诊断BP神经网络模型,采用实际的HFC上行信道数据对网络进行训练.仿真表明,应用LM神经网络算法后故障诊断准确率达到85%以上,该方法具有一定的参考及实用价值.

  12. A biodegradabilidade da blenda de poli(β-Hidroxibutirato-co-Valerato/amido anfótero na presença de microrganismos The Biodegradation of polyhydroxybutyrate-co-valerate/amphiprotic starch in the presence of microorganisms

    Directory of Open Access Journals (Sweden)

    Nadjane S. Coelho

    2008-09-01

    Full Text Available O crescimento do consumo de plásticos vem gerando grandes problemas ambientais, pois um polímero, uma vez descartado no ambiente, necessita de mais de cem anos para se degradar. O plástico ideal deve apresentar propriedades industriais desejáveis e, ao mesmo tempo ser degradável num período considerado satisfatório. Busca-se desenvolver plásticos com boas propriedades para embalagens e que possam ser biodegradados quando descartados ao ambiente. Neste trabalho avaliamos a biodegradação da blenda do copolímero poli(β-hidroxibutirato-co-valerato, PHB-HV, que é um termoplástico natural, biodegradável e biocompatível, e do amido anfótero, na proporção de 75 e 25% m/m, respectivamente. Os resultados foram obtidos através do teste de Sturm, uma metodologia para a avaliação da biodegradação na presença de uma cultura mista dos fungos Phanerochaete chrysosporium e Talaromyces wortmannii. Os resultados evidenciam a biodegradação da blenda em função do tempo, de acordo com os resultados do teste de Sturm, com o aparecimento de grupos carboxílicos terminais. Foi detectado também o aparecimento de nova simetria cristalina na estrutura polimérica.The increasing consumption of plastics has generated environmental problems because it takes more than a hundred years for a discarded polymer to degrade. The ideal plastic should present desirable industrial properties and be degradable within a satisfactory time period. Researches is conducted to plastics with good properties for packaging, but that are biodegradable when discarded to the environment. In this work we evaluated the biodegradation of the blend of the copolymer poly(hydroxybutyrate-hydroxyvalerate, PHB-HV, which is a natural, biodegradable and biocompatible thermoplastic, and of the starch amphiprotic, in the proportion of 75 and 25% m/m, respectively. The results were obtained through the Sturm test, a methodology for the evaluation of biodegradation in the presence

  13. Anurofauna da bacia do Rio Tijuco, Minas Gerais, Brasil e sua relação com taxocenoses de anfíbios do Cerrado e suas transições

    Directory of Open Access Journals (Sweden)

    Carlos E. Conte

    2013-09-01

    Full Text Available A supressão de paisagens naturais tem dizimado populações e/ou reduzido a área de ocorrência de muitas espécies de anuros, caso do Cerrado, dado o grande potencial econômico e velocidade de descaracterização por atividades humanas. Por este motivo, inventários de espécies são extremamente necessários nessas regiões que dependendo do grau de alteração ambiental podem prejudicar as atividades de dispersão e reprodução dos anuros. Este estudo tem por objetivo determinar a riqueza e a diversidade de modos reprodutivos da anurofauna da bacia do Rio Tijuco e comparar a composição da taxocenose dessa região com taxocenoses de anfíbios de outras regiões do bioma Cerrado e da floresta estacional semidecidual anteriormente estudadas. O estudo foi desenvolvido ao longo da bacia do Rio Tijuco numa extensão aproximada de 80 km. Através de quatro métodos de amostragem, foram registradas 40 espécies de anuros pertencentes a seis famílias, o que corresponde a 20% das espécies de anuros registradas para o Cerrado. As condições da paisagem favorecem espécies mais tolerantes e adaptadas ao clima mais seco, o que reflete numa taxocenose que possui baixa proporção de modos reprodutivos e uma elevada representatividade de modos generalizados, dependentes de água ou com adaptações contra dessecação. Em comparação com outras 15 localidades verificou-se que a anurofauna do Cerrado é típica, com baixa similaridade taxonômica com ecossistemas adjacentes. A diversidade de habitats e a expressiva riqueza de espécies tornam a bacia do Rio Tijuco de grande importância para a conservação da anurofauna do bioma Cerrado.

  14. (Vapour + liquid) equilibria of the {l_brace}carbon dioxide + pentafluoroethane (HFC-125){r_brace} system and the {l_brace}carbon dioxide + dodecafluoro-2-methylpentan-3-one (NOVEC{sup TM}1230){r_brace} system

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Keesin [School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Shinlim-dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Im, Jihoon [School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Shinlim-dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Lee, Sukyung [Department of Safety Engineering, Seoul National University of Technology, Gongneung2-dong, Nowon-gu, Seoul 139-743 (Korea, Republic of); Kim, Hwayong [School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Shinlim-dong, Gwanak-gu, Seoul 151-744 (Korea, Republic of)]. E-mail: hwayongk@snu.ac.kr

    2007-04-15

    Binary (vapour + liquid) equilibrium data were measured for the {l_brace}carbon dioxide + pentafluoroethane (HFC-125){r_brace} system at temperatures from 313.15 K to 333.15 K and the {l_brace}carbon dioxide + dodecafluoro-2-methylpentan-3-one (NOVEC{sup TM}1230){r_brace} system at temperatures from 313.15 K to 343.15 K. These experiments were carried out with a circulating-type apparatus with on-line gas chromatography. The experimental data were correlated well by the Peng-Robinson equation of state using the Wong-Sandler mixing rules.

  15. Cycle performance studies on a new HFC-161/125/143a mixture as an alternative refrigerant to R404A

    Institute of Scientific and Technical Information of China (English)

    Xiao-hong HAN; Yu QIU; Ying-jie XU; Men-yuan ZHAO; Qin WANG; Guang-ming CHEN

    2012-01-01

    In this paper,a new ternary non-azeotropic mixture of HFC-161/125/143a (0.15/0.45/0.40 in mass fraction),as a promising mixed refrigerant to R404A,is presented.The ozone depletion potential (ODP) of the new refrigerant is zero and its basic thermodynamic properties are similar to those of R404A,but its global warming potential (GWP) is much smaller than those of R507A and R404A.Meanwhile,theoretical calculations show that,under the working condition Ⅰ (the average evaporation temperature:-23 ℃,the average condensing temperature:43 ℃,the superheat temperature:28 ℃,the subcooling temperature:5 ℃),the volumetric refrigerating effect and specific refrigerating effect of the new mixture are 2.33% and 15.48% higher,respectively,than those of R404A.The coefficient of performance (COP) of the new mixture is 5.19% higher than that of R404A and the pressure ratio of the new mixture is 0.82% lower than that of R404A.Equally,under the working condition Ⅱ (the average evaporation temperature:-40 ℃,the average condensing temperature:35 ℃,the superheating temperature:30 ℃,the subcooling temperature:5 ℃),the volumetric refrigerating effect and specific refrigerating effect of the new mixture are 2.24% and 20.58% higher,respectively,than those of R404A.The COP of the new mixture is 4.60% higher than that of R404A and the pressure ratio of the new mixture is similar to that of R404A.The performances of the new mixture and R404A are compared in a vapor compressor refrigeration apparatus originally designed for R404A under several working conditions (condensing temperatures:35-45 ℃,evaporation temperatures:-40-20 ℃).Experimental results show that the new mixture can obtain a higher COP,by 6.3% to 12.1%,and a lower pressure ratio,by 1.8% to 6.6%,compared to R404A; although the discharge temperature of the new mixture is slightly higher than that of R404A.The advantages of the new mixture will be further verified in the actual system.

  16. 血浆ANF与99mTc-DTPA肾动态显像的联合监测在糖尿病肾病中的意义%Plasma ANF and 99mTc-DTPA Renal Dynamic Imaging Combined Monitoring in the Significance of Diabetic Nephropathy

    Institute of Scientific and Technical Information of China (English)

    余飞; 吕明丽; 蔡海东; 李丹; 袁雪宇; 吕中伟

    2013-01-01

    目的:通过血浆ANF与99mTc-DTPA肾动态显像的联合测定,对糖尿病肾病(DN)进行准确的诊断和临床分期.方法:选取我院70例2型糖尿病(DM2)患者(排除心、脑、血管疾病、泌尿系感染)及正常健康者40名作为正常对照组.70例DM2患者分为2组,A组35例为早期DN组,糖尿病病程为(5~10)年,血BUN、Cr没有明显变化,B组35例为中晚期DN组,糖尿病病程>10年,血BUN、Cr有不同程度升高.分别测定血浆ANF和GFR.结果:A组及B组ANF含量均高于正常对照组(P<0.01),且B组明显高于A组(P<0.01);A组GFR测定高于正常对照组(P<0.05),B组GFR低于正常对照组(P<0.01).结论:实验表明,DN早期GFR值升高,ANF值升高,中晚期DN患者GFR值降低,但ANF值升高更为明显.%Objective The study examined GFR by the 99mTc-DTPA renal dynamic imaging and plasma ANF to get the diabetic nephropathy's definite diagnosis and the clinical stages. Methods selected 70 patients with type 2 diabetes in our hospital ( barring the heart, brain, vascular diseases and urinary tract infection) and 40 normal healthy persons served as control group. 70 cases of type 2 diabetes patients were divided into two groups, Group A with 35 cases of early diabetic nephropathy, duration of diabetes for 5-10 years, blood BUN, Cr changed unsignificantly, Group B with 35 cases of middle-late diabetic nephropathy, duration of diabetes >10 years, blood BUN, Cr showed different levels rising. Results ANF examination, both of A group and B were higher than those in control group, the difference is highly significant (P <0.05) and B group obviously higher than the group A, the difference is highly significant (P<0.05) ; GFR examination, the group A higher than that of control group, the difference is significant (P <0.05), group B manifested below the control group, the difference showed markedly significant (P<0.05) Conclusion The experiment indicated, in early stage of diabetic nephropathy GFR is increasing

  17. Inventory and calculation potential and real emissions of HFCs, FCs and SF{sub 6} in Sweden; Kartlaeggning och beraekning av potentiella och faktiska utslaepp av HFC, FC och SF{sub 6} i Sverige

    Energy Technology Data Exchange (ETDEWEB)

    Kindbom, K.; Haeger Eugensson, M.; Persson, Karin

    2001-08-01

    On behalf of the Swedish Environmental Protection Agency, the Swedish Environmental Research Institute (IVL) has made an inventory of the flow of HFCs, FCs and SF{sub 6} in Sweden. Calculations of annual emissions of these substances have been made according to procedures given in the IPCC, Guidelines for National Greenhouse Gas Inventories. Two methods of calculations have been used, the Tier 1b method for potential emissions, and Tier 2 covering actual emissions. According to the UN Framework Convention on Climate Change, countries may report either potential or actual emissions. Until now only potential emissions have been calculated and reported from Sweden. HFCs, PFCs and SF{sub 6} are used in different applications in Sweden, such as: Refrigeration and air conditioning: HFCs, PFCs; Foam blowing: HFC-134a and HFC-152a; Fire extinguishing: HFCs; Aerosol propellant: HFCs; Solvent: PFC; Semiconductor industry: PFC, HFC, SF{sub 6}; Aluminium production (byproducts in process): PFCs; Magnesium smelting: SF6; Electrical insulation: SF6; Double glazing: SF{sub 6}; Jogging shoes: SF{sub 6}. Necessary data, in order to make the calculations of emissions, was collected for all above mentioned applications. As far as possible a 'bottom up' approach has been used, where the number of units containing the substances, or the total annual amount installed or used within a particular area of application, has been used as a basis for the calculations. Information as to amount of chemical per unit, emission factors at production, during usage and at disposal, as well as figures on imported and exported number of units or amount of chemical is also necessary. Data collected consists of information compiled from trade associations, industrial users of the substances, retailers, from official statistical databases and also from the register at the Swedish National Chemicals Inspectorate where imported and exported amounts of the chemicals in bulk are registered. The

  18. Effects of Phase Change and Oxygen Permeability in Oxide Scales on Oxidation Kinetics of ZrB2 and HfB2 (POSTPRINT)

    Science.gov (United States)

    2009-11-01

    well. Alloying additions that sup- press or delay the phase transformation would be beneficial. V. Summary A wide range of experimental data on the...Materials,’’ SAMPE Quar- terly, 2 [3] 1–15 (1971). 10J. B. Berkowitz-Mattuck, ‘‘High-Temperature Oxidation III : Zirconium and Hafnium Diborides,’’ J...1959). 30L. Kaufman, E. V. Clougherty, and J. B. Berkowitz-Mattuck, ‘‘Oxidation Characteristics of Hafnium and Zirconium Diboride,’’ Trans. of Met. Soc

  19. Especie nueva de anfípodo comensal (Amphipoda: Gammaridea: Leucothoidae del Parque Nacional Sistema Arrecifal Veracruzano, SO del golfo de México A new species of commensal amphipod (Amphipoda: Gammaridea: Leucothoidae from Veracruz Coral Reef System, S W Gulf of Mexico

    Directory of Open Access Journals (Sweden)

    Ignacio Winfield

    2009-08-01

    Full Text Available Se describe una especie nueva de anfípodo comensal del género Leucothoe (Leucothoidae del Parque Nacional Sistema Arrecifal Veracruzano, Veracruz, SO del golfo de México. Los organismos fueron recolectados de la esponja Aplysina fistularis a 10 m de profundidad. La especie nueva se compara morfológicamente con otras especies relacionadas. Coxa 2 con esquina anterior aguda; propodio del gantópodo 2 con 7 setas largas subapicales, 1 hilera de 27-28 setas gruesas mediales y 7 setas submarginales; artejo 2 del palpo mandibular con 5 setas y margen distal aserrado; último artejo del maxilípedo con uña distal y margen interno cubierto con espínulas pequeñas; telson triangular, trífido distalmente, con 2 setas apicales y 2 pares de setas pectinadas medialmente, constituyen las características distintivas de Leucothoe hortapugai.A new species of commensal amphipod of the genus Leucothoe (Leucothoidae is described from the Veracruz coral reef system, Veracruz, in the SW Gulf of Mexico. The specimens were collected from the sponge Aplysina fistularis at a depth of 10 m. The new species is compared to other closely related species of Leucothoe. Coxa 2 with acute anterior corner; propodus of gnathopod 2 with 7 long subapical setae, 27-28 thick medial setae arranged in 1 row, and 7 short submarginal setae; segment 2 of mandible palp with 5 setae and distal margin serrate; last segment of maxilliped palp with distal nail and inner margin covered with small spinules; telson triangular, trifid distally, including 2 apical setae and 2 pairs of medial pairs of plumose setae, are the main characteristics of Leucothoe hortapugai.

  20. Escolha de áreas prioritárias de conservação de anfíbios anuros do Cerrado através de um modelo de populações centrais-periféricas Reserve selection for anurans in the Cerrado using a central-periphery population model

    Directory of Open Access Journals (Sweden)

    Gabriela C. C. Padua

    2008-06-01

    Full Text Available Uma das maiores ameaças à diversidade biológica é a perda de hábitat, de modo que uma das alternativas para proteção da biodiversidade é a seleção de reservas pela utilização de procedimentos de otimização para estabelecer áreas prioritárias para conservação. Neste estudo, um algoritmo simulated annealing foi usado para verificar como a periferia das distribuições das espécies influencia na seleção de áreas no Cerrado para conservação de 131 espécies de anfíbios anuros. Dois conjuntos de dados foram analisados, um contendo a distribuição original das espécies e outro excluindo a periferia das distribuições. As redes ótimas encontradas a partir das distribuições originais contiveram 17 quadrículas enquanto aquelas encontradas a partir das distribuições restritas foram maiores, com 22 células. As células com alto grau de insubstituibilidade foram mantidas em todas as redes e novas regiões de células substituíveis, localizadas na margem do bioma, surgiram quando apenas as distribuições reduzidas foram usadas.Habitat loss causes great threats to biological diversity, and one of the alternatives to protect biodiversity is reserve planning using optimization tools to establish conservation priority areas. In this study, a simulated annealing algorithm was used to analyze the influence of species distribution margins on selection of areas in Cerrado, for 131 anurans species. For this purpose, we used two databases: one containing the original species distribution, and another with the periphery of distributions excluded. Networks selected using the original distributions contained 17 cells, whereas networks found with the reduced distributions were larger, with 22 cells. The irreplaceable cells were the same in all networks, and new regions of replaceable cells in the margins of the biome arise when distributions without peripheral areas were considered.

  1. Wood anatomical variation in relation to latitude anf altitude

    NARCIS (Netherlands)

    Graaff, van der N.A.; Baas, P.

    1974-01-01

    The wood anatomical variation within 17 eurytherm hardwood genera in relation to altitude and latitude has been studied using wood samples from 52 species. With increasing latitude a miniaturization of secondary xylem elements (shorter vessel members, narrower vessels, shorter and sometimes narrower

  2. Distribuição temporal e diversidade de modos reprodutivos de anfíbios anuros no Parque Nacional das Emas e entorno, Estado de Goiás, Brasil Temporal distribution and diversity of reproductive modes in anuran amphibians in the Emas National Park and surrounding area, State of Goiás, Brazil

    Directory of Open Access Journals (Sweden)

    Katia Kopp

    2010-09-01

    Full Text Available As comunidades de anfíbios anuros, principalmente de regiões tropicais, são influenciadas diretamente pelas condições ambientais, as quais desempenham um papel importante na estruturação e regulação das comunidades. Esse estudo teve como objetivo determinar a diversidade de modos reprodutivos, a temporada de vocalização e testar a correlação das variáveis climáticas sobre a riqueza, a abundância dos anuros adultos e dos girinos e sobre a atividade de vocalização dos machos em 12 corpos d'água localizados no interior e entorno do Parque Nacional das Emas, sudoeste do estado de Goiás, Brasil. Foram realizadas 16 amostragens entre dezembro de 2005 e março de 2008. Um total de 25 espécies de cinco famílias foram registradas: Bufonidae (uma espécie, Hylidae (nove espécies, Leptodactylidae (oito espécies, Leiuperidae (seis espécies e Microhylidae (uma espécie. Quatro padrões de atividade reprodutiva foram reconhecidos entre as espécies: contínuo, intermediário, prolongado e explosivo. A riqueza de anuros adultos, a abundância e atividade de vocalização dos machos foram positivamente relacionadas com a temperatura do ar, umidade e precipitação. A riqueza de girinos foi positivamente relacionada com a precipitação e com a temperatura da água, mas não houve relação da abundância de girinos com nenhum dos descritores climáticos. Foram registrados seis modos reprodutivos: 56% das espécies apresentaram modos reprodutivos aquáticos generalizados (modo 1 e 4, e 44% depositam os ovos em ninhos de espuma (modos 11, 13, 30 e 32. As espécies registradas no presente estudo apresentaram predominância de modos reprodutivos generalizados e padrão reprodutivo tipicamente associado ao período quente e chuvoso, como esperado para regiões tropicais sazonais. Entretanto, a segregação temporal entre grupos de espécies dentro do período chuvoso parece facilitar a coexistência de espécies generalistas típicas de

  3. HFC perspectives in air-conditioning and refrigeration; Perspectives HFC en A/C et refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Fauvarque, P. [ELF Atochem, Centre d`Application de Lavallois, 92 (France)

    1997-12-31

    This paper is a series of transparencies dealing with the development of substitutes for the replacement of the R-22 refrigerant in air-conditioning systems (R-134a, R-407C, R-410A), and in industrial refrigeration systems of agriculture and food industry (R-134a and R-404A). (J.S.)

  4. Une activité touristique et de loisir « amphibie » entre espaces de pratiques et territoires de gestion : la plaisance Uma atividade turística e de lazer “anfíbia” entre espaços de práticas e territórios de gestão : o nautismo

    Directory of Open Access Journals (Sweden)

    Ewan Sonnic

    2010-03-01

    of coincidence between practice spaces and management spaces is such as to lead several actors (territorial collectivities, decentralized services of the State, research departments, associations… to operate more and more within the framework of territories copied on practice spaces. The latter remain nevertheless largely fixed by traditional administrative cuttings and see their regularly redefined.Na era do turismo de massa e dos lazeres, o nautismo é uma expressão específica de territorialidade, através de diversos equipamentos construidos na costa (portos, marinas, estaleiros navais, etc. e dos fluxos tanto marítimos como terrestres (itinerários no mar dos iatistas, entre portos e objetivos, ligações domicílio-pontos de embarque, ligações domicílio-trabalho dos profissionais do nautismo, etc.. Este caráter “anfíbio” confere ao nautismo um lugar atípico entre as atividades turísticas.Na França, mais que outros lazeres, o nautismo é esquartejado entre espaços vividos, resultando essencialmente dos percursos dos iatistas (bacias de navegação, bacias de cruzeiro, bacias de nautismo…, e dos territórios administrativos que pertencem a uma lógica bem diferente na terra (coletividades territoriais, subdivisões dos negócios marítimos como no mar (águas territoriais, zona de exercício do direito de polícia.Em conformidade com muitos outros espaços vividos, as áreas de práticas do nautismo são particularmente complexas. Para além do seu caráter crónico, tendo em conta o caráter essencialmente sazonal da atividade, estes territórios vão depender da diversidade das práticas (pesca, passeio no mar, cruzeiro costeiro, cruzeiro do alto mar, vela desportiva…, do regulamento em vigor que proibe a navegação além de certa distância de um abrigo, de acordo com as diferentes categorias de navios, etc. Por a sua parte, os territórios de gestão dependem de uma lógica largamente continental, mesmo perto da costa. A não coincid

  5. Oxidation Resistance, Electrical and Thermal Conductivity, and Spectral Emittance of Fully Dense HfB2 and ZrB2 with SiC, TaSi2, and LaB6 Additives

    Science.gov (United States)

    2012-01-26

    ZrB2 . a. Single crystal SiC (R66) plotted in Watari et al. [16], based on Slack [17]. b. Mixture of α and β SiC hot pressed with BeO sintering aid, 100...Properties of ZrB2 and ZrB2-SiC Ceramics,” J. Am. Ceram. Soc., 91 [5] 1405-1411 (2008). [16] K. Watari , H. Nakano, K. Sato, K. Urabe, K. Ishizaki, S. Cao

  6. Hfc-134a Ve Alternatifi Soğutkanların (Hfo-1234yf Ve Hfo-1234ze) Soğutma Çevrimi Performansı Açısından Karşılaştırması

    OpenAIRE

    Arif Emre ÖZGÜR

    2014-01-01

    Bu çalışmada, alternatif soğutucu akışkanlar olarak günümüzde ön plana çıkan, HFO-1234yf ve HFO- 1234ze’nin, bir buhar sıkıştırmalı mekanik soğutma çevriminin etkinliğine ve ekserji verimine olan etkileri teorik olarak incelenmiştir. HFO-1234yf ve HFO-1234ze soğutkanları, HFC-134a soğutucu akışkanlarına alternatif olarak önerildiği için bu üç akışkanın, aynı çevrim ve çalışma aralıklarında, çevrim etkinliğine ve çevrimin ekserji verimine etkileri karşılaştırmalı olarak sunulmuştur ve bu akışk...

  7. New or rare frogs from the Coastal Ranges of Brazil: eleutherodactylus venancioi n.sp., E. hoehnei n.sp. Holoaden bradei n.sp. e H. lüderwaldti Mir. Rib., 1920 Anfíbios novos e raros das Serras Costeiras do Brasil: eleutherodactylus venancioi n.sp., E. hoehnei n.sp. Holoaden bradei n.sp. e H. lüderwaldti Mir. Rib., 1920

    Directory of Open Access Journals (Sweden)

    Bertha Lutz

    1958-12-01

    Full Text Available Field-work in the sierras near the sea-board of south-eastern Brazil continues to yield new or rare frogs. Four more of these forms are presented here. Two of them, both new, are put into the genus Eleutherodactylus, to which they belong by their general habitat, morphology, and also by the osteological characters. They differs from the known regional species of this genus only by the wider and shorter disks of some of the digits and the more lanceolate build. The other two species belong to the very little known genus Holoaden, established by MIRANDA RIBEIRO in 1920. One of them is his type-species, H. lüderwaldti, which continues to be very rare. The other, H. bradei, is new. It seems endemic to the Upper Itatiaia and is very plentiful there.O trabalho de campo nas serras vizinhas do nosso litoral continua a render anfíbios novos e raros. Aos já versados em publicações anteriores, acrescentamos as quatro espécies que formam o assunto so presente trabalho. Duas delas, ambas novas, pertencem ao gênero Eleutherodactylus, não só pelo seu hábitat e sua morfologia como também pelos caracteres osteológicos, verificados em exemplares diafanisados pelo meu ilustre colega Sr. ANTENOR LEITÂO DE CARVALHO e estudados por ambos os herpetólogos do Museu Nacional. Diferem das outras espécies do gênero pertencentes á fauna regional apenas pelo porte lanceolado e esgio e pelos discos mais curtos e mais largos de alguns dos dedos. As fêmeas da espéciemenor continham um certo número de ovos macrolecitais, característicos do gênero, cujo desenvolvimento é embrionário, sem fase larval. É interessante notar que, em duas delas, só os ovários direitos eram perceptíveis externamente. As outras duas espécies aqui versadas se filiam ao gênero Holoaden criado, em 1920, pelo nosso eminente predecessor, Professor ALIPIO DE MIRANDA RIBEIRO. Trata-se do genótipo, H. lüderwaldti, que continua a ser raríssimo, e de H. bradei nov. sp., que

  8. Australian HFC, PFC and SF6 emissions: atmospheric verification

    Science.gov (United States)

    Fraser, P.; Dunse, B.; Krummel, P. B.; Steele, P.; Manning, A. J.

    2011-12-01

    The synthetic greenhouse gases (GHGs: hydrofluorocarbons - HFCs, perfluorocarbons - PFCs, and sulfur hexafluoride - SF6), emitted largely by the refrigeration, aluminium and electricity distribution industries respectively, are currently responsible for less than 2% of Australia's net long-lived GHG emissions (DCCEE, 2011). Nevertheless, they have attracted the attention of policymakers because (1) if their growth in concentrations and emissions continues unabated, particularly HFCs - currently growing at 10% per year - then they could be responsible globally (and in Australia) for more than 10% of the radiative forcing due to long-lived GHGs by 2050 (Velders et al., 2009); and (2) they provide the opportunity for a very cost-effective GHG mitigation strategy, because emissions can be reduced significantly through better engineering to minimize emissions, through a ban on dispersive uses (as solvents for example) and through the use of low GWP (Global Warming Potential) alternatives (for example hydrofluoroethers - HFEs). CSIRO, through its involvement in the AGAGE global program of monitoring non-carbon dioxide GHGs (Prinn et al., 2000), has been making high precision in situ measurements (12 per day) of HFCs, PFCs and SF6 at Cape Grim, Tasmania, since 2004, using a gas chromatograph-mass spectrometer detector (GC-MSD) fitted with a custom-built cryo-focussing unit (Medusa: Miller et al., 2008). The resultant data have been used to derive Australian emissions by inverse modelling (NAME, TAPM) and interspecies correlation (ISC). The overall agreement between so-called bottom-up estimates of Australian emissions, as reported to the UNFCCC (United Nations Framework Convention on Climate Change), and top-down estimates from atmospheric observations, using NAME, TAPM and ISC, is encouraging. Australian UNFCCC reported emissions (DCCEE, 2011) generally agree to within of 10% of emissions calculated from Cape Grim data, scaled on a population basis, with some notable exceptions. References DCCEE (2011), Australian National Greenhouse Accounts, National Inventory Report 2009, Volume 1, Australian Government Department of Climate Change and Energy Efficiency, 284 pp, April 2011. Miller, B., R. Weiss, P. Salameh, T. Tanhua, B. Greally, J. Muhle & P. Simmonds, Medusa: a sample pre-concentration and GC-MS detector system for in situ measurements of atmospheric trace halocarbons, hydrocarbons and sulphur compounds, Anal. Chem., 80 (5), 1536-1545, 2008. Prinn, R., R. Weiss, P. Fraser, P. Simmonds, D. Cunnold, F. Alyea, S. O'Doherty, P. Salameh, B. Miller, J. Huang, R. Wang, D. Hartley, C. Harth, P. Steele, G. Sturrock, P. Midgley & A. McCulloch, A history of chemically and radiatively important gases in air deduced from ALE/GAGE/AGAGE, Journal of Geophysical Research - Atmospheres, 105 (D14): 17751-17792, 2000.

  9. Atmospheric chemistry of CH3CHF2 (HFC-152a)

    DEFF Research Database (Denmark)

    Taketani, Fumikazu; Nakayama, Tomoki; Takahashi, Kenshi

    2005-01-01

    Smog chamber/Fourier transform infrared (FTIR) and laser-induced fluorescence (LIF) spectroscopic techniques were used to study the atmospheric degradation of CH3CHF2. The kinetics and products of the Cl(2P(3/2)) (denoted Cl) atom- and the OH radical-initiated oxidation of CH3CHF2 in 700 Torr of ...

  10. Refrigerating fluids. Options. A manufacturer selects three HFC fluids; Fluides Frigorigenes. Options. Un fabricant retient trois fluides HFC

    Energy Technology Data Exchange (ETDEWEB)

    Haentjens, H.

    1999-12-01

    Because of the scheduled replacement of CFC and HCFC fluids in refrigerating systems, the Carrier company, number one in the manufacturing of air conditioning systems, has retained 3 hydro-fluorocarbon refrigerants: R 134a, R 407C and R 410A. Each fluid has different thermodynamical properties and is specifically used for a given range of powers: above 300 kW for R 134a, between 15 and 300 kW for R 407C and below 15 kW for R 410A. The choices made by other manufacturers are given as a comparison. (J.S.)

  11. Anfíbios Anuros do Distrito Federal The Frogs of the Federal District of Brazil

    Directory of Open Access Journals (Sweden)

    Bertha Lutz

    1954-03-01

    Full Text Available The frogs of the Federal District of Brazil are listed and discussed as to habit, biology and ecology. The F. D is situated 22° 54' 24" S. & 43° 10' 21" W Gr. and comprises 1.356 km². Its topography includes sea-shore, maritime scrub, lagoons, plains and marsh, open slopes, forested mountains and great heads of rock. Three thousand feet of altitude are attained at two points. Fifty two different frogs occur in the F.D. Three fifths of them live in open country. Two fifths of these have never been found above the plains; the others range higher but mostly in open country. Their environment offers conditions suitable for average tadpoles and adults. these frogs are more or less unspecialized. There are six genera and thirty species. Two thirds of the latter belong to the type genera of the large neotropical families Bufonidae, Leptodactylidae and Hylidae. Only in the maritime scrub formation are conditions somewhat different. Water for average tadpoles is provided by the lagoons. The xerophytism of the vegetation is, however, so marked that bromeliads growing on the ground provide almost the only appropriate shelter for adult tree-frogs used to sleeping upright on the vegetation. One large Hylid genus lives entirely in them. It is casque-headed and phragmotic, shutting the lumen of the leaf-cup with head used as a plug. Another large Hylid genus shows a lesser degree of the same specialization. (Lutz A & Lutz B, 1939 II. One genus with two species is entirely saxicolous; it lives on wet ledges of rock at all phases of its life history. (B. Lutz 1948. The other two fifths of the frogs from F. D. are montane forest forms. Their environment offers numerous and varied biotopes and is near optimum for adults. There is,however, hardly any standing water available for larvae. These frogs are ecologically diversified. They also show a general trend towards spawning in the adult biotipe, which leads to delayed hatching, semi-aquatic and terrestrial larvae and direct development. (B Lutz, 1948. The author interprets the morphological specialization of the casque-headed Hylids and the biological specialization of the montane forest forms as adaptive. Casque-headedness and phragmosis increase protection against blood-suckers and predators. The humidity of the rain forest permits eggs, embryos and larvae to develop, unharmed, outside their usual, aquatic, environment.

  12. Vor Kindle: Die Anfänge des E-Books

    Directory of Open Access Journals (Sweden)

    Anja Jungbluth

    2015-12-01

    Full Text Available E-Books gewinnen in Bibliotheken immer stärker an Bedeutung. In Bezug auf Erwerbung, Einarbeitung und Benutzung gibt es bei E-Books im Vergleich zu klassischen Print-Büchern allerdings große Unterschiede, von denen einige in diesem Artikel erläutert werden. Grundlegende technische Enwicklungen, die bei der Verbreitung der eletronischen Bücher eine wichtige Rolle gespielt haben, darunter historische und heute übliche Dateiformate sowie eine Übersicht über die ersten Lesegeräte bis hin zum Kindle, mit dem der E-Book-Reader den Durchbruch auf dem Mainstream-Markt schaffte, werden vorgestellt. Ein kurzer Überblick über drei wichtige Problemfelder, mit denen gerade Bibliotheken im Zusammenhang mit der steigenden Verbreitung von E-Books zu kämpfen haben (Lizenzierung, Kosten und Datenschutz, rundet den Beitrag ab.

  13. Net Heat of Combustion of AN-F-28 Aviation Gasolines

    Science.gov (United States)

    1945-06-01

    paraffins~" and iso —paraffins v;ere taken from references 2, 3, and 5. The points’ in figure 1 designated as representing data on iso —paraf fins are...8217 1364-1 3600 13333 6700 • i 13651 3700 13343 6soo .•••;> 13661 3300 13353 * 6900 :r:. 13671 3900 13363 «F a Calculated from the equation Qn(net

  14. Die Anfänge des Sufismus The beginnings of the Sufism

    Directory of Open Access Journals (Sweden)

    Hüseyin DEMİR

    2013-09-01

    Full Text Available The concept of asceticism, which has evolved over time, rests onthe idea of taking a clear stand for a specific lifestyle that favorsabstinence and restraint. What was first practiced by ProphetMuhammad who lived a humble lifestyle devoid any exhibitionism waslater widely spread among his companions. As such, this kind oflifestyle conformed to the Quranic concepts of purification and piety(taqwa. Building on the belief that worldly life is only temporary,asceticism calls for resisting and not giving in to worldly pleasures andtemptations. Against the background of a number of hardships andmoral deviations encountered by Muslim societies, it was to bringforward the movement of Sufism towards the end of the second Hijricentury. Sufism started to obtain the characteristics of a massmovement from the twelfth century onwards and organized itself intariqas simultaneously starting to provide guidance to society inreligious and social terms. These tariqas whose evolution and activitiescan be traced back in time were to split into various subgroups over thecenturies, each of them following the same goal of getting closer toAllah. This piece of writing explores the causes that gave birth to thetariqas, depicts their evolution and main objectives, and examines theirdifferent manifestations. Twelve different tariqas are analyzedcomparatively against a set of criteria including, for example, the roleand form of dhikr (remembrance of Allah. Zamanla gelişen ve hayata karşı bir tavır alma olan zühd anlayışı, Peygamber Efendimiz’in döneminde sade ve gösterişten uzak yaşantısıyla başlayıp daha sonra sahabe-i kiram genelinde gözlemlenir. Kuran-ı Kerim’de tezkiye ve takva kelimeleri ile ifade edilen bu hal, dünyanın geçiciliğine inanarak nefsin hoşuna giden şeyleri gönülden atma ve onlara değer vermeme anlamına gelen zühd olgusu, zamanla müslümanlar arasında başgösteren sapmalar, yeni şartlar, ekonomik, ideolojik, sosyal ve özellikle siyasi hayatın getirmiş olduğu olumsuzluklar sonucunda hicri ikinci asrın sonlarına doğru tasavvuf hareketini ortaya çıkarmıştır. Tasavvuf hareketi 12. yüzyıldan itibaren kitlesel bir karakter kazanmış ve çeşitli tarikatlar şeklinde teşkilatlanarak, toplumu sosyal ve dini açıdan yönlendirmeye başlamıştır. Tarihsel gelişim süreci içerisinde varlıkları, faliyetleri ve çalışma yöntemleri izlenebilen bu tarikatlardan her biri daha sonra çeşitli kollara ayrılarak Allah’a ulaşmayı kendilerine hedef kılmışlardır. Bu çalışmada tarikatların zaman içerisinde ortaya çıkma sebepleri, gelişmesi, zaman içerisinde bir tarikat hareketine dönüşme süreci, tarikatın temel hedefleri ve çeşitli tarikat yolları arasındaki temel farklara değinilmiştir. Çalışma içerisinde tarikatın farklı sınıflandırılmaları arasında tarikatlar zikir çekip çekmemelerine göre, zikir çekenler ise usul ve yöntemlerine göre, zikrin dışında merkeze aldıkları değerlere göre sınıflandırılmaları analiz edilirken, meşhur olmuş 12 tarikatın da mukayeseli analizi yapılmıştır. Tasavvuftan tarikata ve tarikat içerisindeki ekollere geçiş sürecindeki değişimler ve bu çeşitli tarikat ekollerinin temel özellikleri de çalışmanın ana konusunu oluşturmaktadır.

  15. Organic silicon compounds anf hydrogen sulfide removal from biogas by mineral and adsorbent

    Science.gov (United States)

    Choi, J.

    2015-12-01

    Biogas utilized for energy production needs to be free from organic silicon compounds and hydrogen sulfide , as their burning has damaging effects on utilities and humans; organic silicon compounds and hydrogen sulfide can be found in biogas produced from biomass wastes, due to their massive industrial use in synthetic product,such as cosmetics, detergents and paints.Siloxanes and hydrogen sulfide removal from biogas can be carried out by various methods (Ajhar et al., 2010); aim of the present work is to find a single practical andeconomic way to drastically and simultaneously reduce both hydrogen sulfide and the siloxanes concentration to less than 1 ppm. Some commercial activated carbons previously selected (Monteleoneet al., 2011) as being effective in hydrogen sulfide up taking have been tested in an adsorption measurement apparatus, by flowing both hydrogen sulphide and volatile siloxane (Decamethycyclopentasiloxane or D5) in a nitrogen stream,typically 25-300 ppm D5 over N2, through an clay minerals, Fe oxides and Silica; the adsorption process was analyzed by varying some experimental parameters (concentration, grain size, bed height). The best silica shows an adsorption capacity of 0.2 g D5 per gram of silica. The next thermo gravimetric analysis (TGA) confirms the capacity data obtained experimentally by the breakthrough curve tests.The capacity results depend on D5 and hydrogen sulphide concentrations. A regenerative silica process is then carried out byheating the silica bed up to 200 ° C and flushing out the adsorbed D5 and hydrogen sulphide samples in a nitrogen stream in athree step heating procedure up to 200 ° C. The adsorption capacity is observed to degrade after cyclingthe samples through several adsorption-desorption cycles.

  16. Anfíbios Anuros da coleção Adolpho Lutz: III - Hyla claresignata Lutz & B. Lutz, 1939

    Directory of Open Access Journals (Sweden)

    Bertha Lutz

    1948-12-01

    Full Text Available Hyla claresignata Lutz & Lutz, 1939, is a large species apparently not closely allied to the other known Brazilian hylas. It is characterized by the very small tympanum; the head is short and the snout rounded; the legs are long, the hands and feet unusually large, the latter extensively webbbed. The specific name is derived from the insular, irregular, or roughly triangular, dark spots, with a light halo, found mostly in the dorso-lateral region and on the legs. It belongs to the rain-forest fauna of the Marítime Range. The adult is a bromeliad-dweller and the tadpole rhyacophilous. DESCRIPTION. Vomerine teeth in two separate, oblique, groups, behind the large choanae, parallel to the posterior half of their inner border. Tongue entire, short, very broad and hardly free behind. Snout short, rounded, with distinct canthus rostralis and gradually sloping loreal region. Eye very large and prominent, its horizontal diameter almost equal to the distance between its anterior corner and the tip of the snout. Tympanum very small, less than one third of the diameter of the eye, but distinct, partly covered by a short, heavy ridge. Lateral fingers less than one third webbed; fourth finger slightly longer than the second, just reaching the base of the disk of the third; subarticular tubercles well developed; an angular pollex rudiment, more noticeable in the males. Toes almost completely webbed, the edge of the web inserted at the base of the disk on the third and the fifth; an inner metatarsal tubercle. Skin smooth above, granular beneath, on the throat minutely so. No dermal appendage on the hell. Habit robust, head broader than long, body rather heavy, slightly narrowed in the postaxillary region. Legs long, the tibiotarsal articulation reaching beyond the tip of the snout when adpressed. Type (female: 61 mm. (Fig. 1. DIAGNOSIS of TADPOLE (by G. Orton. "A large specialized, mountain-stream tadpole, with wide head an elongated, flattened snout, greatly enlarged lips and high tooth formula. Eyes dorsal. Spiracle sinistral, projecting, situated far back on side. Anus dextral. Tooth formula 8/12 to 9/14 in fully grown larvae. Tail with a prominent, vertical dark band across musculature and fins; a second concentration of dark pigment near tip of tail, may or may not form a similar but narrower band. Maximum known total length: 60mm.; head and body length 25mm. (Figs. 6 e 7. For further details see Lutz & Lutz, 1939 and Lutz B. & Orton G. 1946.

  17. Compatibility of lubricant additives with HFC refrigerants and synthetic lubricants. Final report, Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Cavestri, R.C. [Imagination Resources, Inc., Dublin, OH (United States)

    1997-07-01

    Part one of this research provides manufacturers of components of air-conditioning and refrigeration equipment with a useful list of lubricant additives, sources, functional properties and chemical species. The list in part one is comprised of domestic lubricant additive suppliers and the results of a literature search that was specifically targeted for additives reported to be useful in polyolester chemistry.

  18. A Novel Factor H-Fc Chimeric Immunotherapeutic Molecule against Neisseria gonorrhoeae.

    Science.gov (United States)

    Shaughnessy, Jutamas; Gulati, Sunita; Agarwal, Sarika; Unemo, Magnus; Ohnishi, Makoto; Su, Xia-Hong; Monks, Brian G; Visintin, Alberto; Madico, Guillermo; Lewis, Lisa A; Golenbock, Douglas T; Reed, George W; Rice, Peter A; Ram, Sanjay

    2016-02-15

    Neisseria gonorrhoeae, the causative agent of the sexually transmitted infection gonorrhea, has developed resistance to almost every conventional antibiotic. There is an urgent need to develop novel therapies against gonorrhea. Many pathogens, including N. gonorrhoeae, bind the complement inhibitor factor H (FH) to evade complement-dependent killing. Sialylation of gonococcal lipooligosaccharide, as occurs in vivo, augments binding of human FH through its domains 18-20 (FH18-20). We explored the use of fusing FH18-20 with IgG Fc (FH18-20/Fc) to create a novel anti-infective immunotherapeutic. FH18-20 also binds to select host glycosaminoglycans to limit unwanted complement activation on host cells. To identify mutation(s) in FH18-20 that eliminated complement activation on host cells, yet maintained binding to N. gonorrhoeae, we created four mutations in domains 19 or 20 described in atypical hemolytic uremic syndrome that prevented binding of mutated fH to human erythrocytes. One of the mutant proteins (D to G at position 1119 in domain 19; FHD1119G/Fc) facilitated complement-dependent killing of gonococci similar to unmodified FH18-20/Fc but, unlike FH18-20/Fc, did not lyse human erythrocytes. FHD1119G/Fc bound to all (100%) of 15 sialylated clinical N. gonorrhoeae isolates tested (including three contemporary ceftriaxone-resistant strains), mediated complement-dependent killing of 10 of 15 (67%) strains, and enhanced C3 deposition (≥10-fold above baseline levels) on each of the five isolates not directly killed by complement. FHD1119G/Fc facilitated opsonophagocytic killing of a serum-resistant strain by human polymorphonuclear neutrophils. FHD1119G/Fc administered intravaginally significantly reduced the duration and burden of gonococcal infection in the mouse vaginal colonization model. FHD1119G/Fc represents a novel immunotherapeutic against multidrug-resistant N. gonorrhoeae.

  19. Heat Transfer Evaluation of HFC-236EA and CFC-114 in Condensation and Evaporation

    Science.gov (United States)

    1996-06-01

    41 7.2 Sieder -Tate coefficient data for the four tubes of interest...5.13 STC -- Sieder -Tate coefficient t -- fin thickness (in) T - temperature (C) AT - excess temperature (C) (= Tsat - Tw for condensation and = Tw - Tst...straight line, where X Ak& and (7.9) ii Re°S Pr- 33 °4 r= o- AR . (7.10) Therefore, the slope of the line (m) is the inverse of the required Sieder -Tate

  20. Potential effect of HFC policy on global greenhouse gas emissions in 2035

    NARCIS (Netherlands)

    Kroeze C.; LAE

    1994-01-01

    HFK's (waterstoffluorkoolwasterstoffen) worden gebruikt als substituut voor volledig gehalogeneerde CFK's (chloorfluorkoolwaterstoffen en mogelijk ook voor de onvolledig gehalogeneerde HCFK's. Het doel van deze studie is de wereldwijde HFK-emissie in het jaar 2035 te onderzoeken,

  1. Elastohydrodynamic Lubrication with Polyolester Lubricants and HFC Refrigerants, Final Report, Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Gunsel, Selda; Pozebanchuk, Michael

    1999-04-01

    Lubrication properties of refrigeration lubricants were investigated in high pressure nonconforming contacts under different conditions of temperature, rolling speed, and refrigerant concentration. The program was based upon the recognition that the lubrication regime in refrigeration compressors is generally elastohydrodynamic or hydrodynamic, as determined by the operating conditions of the compressor and the properties of the lubricant. Depending on the compressor design, elastohydrodynamic lubrication conditions exist in many rolling and sliding elements of refrigeration compressors such as roller element bearings, gears, and rotors. The formation of an elastohydrodynamic film separating rubbing surfaces is important in preventing the wear and failure of compressor elements. It is, therefore, important to predict the elastohydrodynamic (EHD) performance of lubricants under realistic tribocontact renditions. This is, however, difficult as the lubricant properties that control film formation are critically dependent upon pressure and shear, and cannot be evaluated using conventional laboratory instruments. In this study, the elastohydrodynamic behavior of refrigeration lubricants with and without the presence of refrigerants was investigated using the ultrathin film EHD interferometry technique. This technique enables very thin films, down to less than 5 nm, to be measured accurately within an EHD contact under realistic conditions of temperature, shear, and pressure. The technique was adapted to the study of lubricant refrigerant mixtures. Film thickness measurements were obtained on refrigeration lubricants as a function of speed, temperature, and refrigerant concentration. The effects of lubricant viscosity, temperature, rolling speed, and refrigerant concentration on EHD film formation were investigated. From the film thickness measurements, effective pressure-viscosity coefficients were calculated. The lubricants studied in this project included two naphthenic mineral oils (NMO), four polyolesters (POE), and two polyvinyl ether (PVE) fluids. These fluids represented viscosity grades of ISO 32 and ISO 68 and are shown in a table. Refrigerants studied included R-22, R-134a, and R-410A. Film thickness measurements were conducted at 23 C, 45 C, and 65 C with refrigerant concentrations ranging from zero to 60% by weight.

  2. Exploring policy strategies for mitigating HFC emissions from refrigeration and air conditioning

    NARCIS (Netherlands)

    Hekkenberg, M.; Uiterkamp, Anton J. M. Schoot

    2007-01-01

    The growing demand for cooling throughout the world, possibly increased by global climate change, requires the implementation of policies to mitigate the related greenhouse gas (GHG) emissions from energy and refrigerant use in the refrigeration and air conditioning (RAC) sector. This article aims t

  3. Elastohydrodynamic Lubrication with Polyolester Lubricants and HFC Refrigerants, Final Report, Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Gunsel, Selda; Pozebanchuk, Michael

    1999-04-01

    The objective of this study was to investigate the film formation properties of refrigeration lubricants using the ultrathin film elastohydrodynamic (EHD) interferometry technique and to study the effects of refrigerants on film formation. Film thickness measurements were conducted as a function of lubricant viscosity, speed, temperature, and refrigerant concentration. Based on the EHD film thickness data, effective pressure-viscosity coefficients were calculated for the test fluids at different temperatures and the effects of refrigerants on pressure-viscosity properties were investigated.

  4. Anchoring of CoHFC nanoparticles on clinoptilolite for remedy of nuclear wastes

    Directory of Open Access Journals (Sweden)

    Yousefi Taher

    2017-01-01

    Full Text Available To improve the mechanical properties, the cobalt ferrocyanide precipitation was carried out on clinoptilolite as an inorganic polymer. In this work the combination of two important factors, stability (zeolite and high adsorption capacity (cobalt ferrocyanide were considered to improve the ions uptake ability of adsorbent. The modification was approved by X-ray diffraction, Scanning electronic microscopy and Fourier transform infrared spectroscopy. The modified zeolite was applied to remove Sr(II and Cs(I ions from aqueous solution in a batch system. The adsorption capacities of modified zeolite for Cs(I and Sr(II improved to 90 and 130 mgg-1, respectively. The Sr(II and Cs(I removal were investigated as a function of shaking time, pH, Sr(II, and Cs(I initial concentration and temperature. The experimental data were fitted well to Langmuir isotherm model for two sorbet metal ions. The time dependence sorption data showed that the uptakes of Cs(I and Sr(II were very rapid and apparent sorption equilibriums were achieved within 100 min of contact time. The kinetic experimental data were fitted to the pseudo-first order, pseudo-second order, the double exponential, Elovich and intraparticle diffusion models. The sorption rates and capacities as well as rate constants were evaluated.

  5. Physicochemical laws of the interaction of nickel aluminides with alloying elements: II. Interaction of nickel aluminides with alloying elements and/or interstitial phases

    Science.gov (United States)

    Povarova, K. B.; Kazanskaya, N. K.; Drozdov, A. A.; Morozov, A. E.

    2007-10-01

    The Ni-Al- X ( X is an interstitial element or phase) phase diagrams are analyzed to reveal systems that can be used as the basis for designing promising alloys and natural composites based on nickel aluminides reinforced by interstitial phases (natural composites I). The most thermally stable materials are shown to be heterophase alloys and composite materials (CMs) located in the eutectic-type (including degenerate eutectic) pseudobinary sections of ternary or multicomponent phase diagrams. They exhibit insignificant (or zero) dissolution of interstitial phases at operating temperatures and the absence of an intense interaction between CM components (natural composites II). Natural composites I based on the NiAl-or Ni3Al-interstitial phase alloys produced upon cooling from a melt can be reinforced by the refractory thermally stable rigid interstitial phases, namely, borides and carbides, that are present in pseudobinary sections in equilibrium with these nickel aluminides, since the elements forming these phases dissolve completely in matrix melts and the mutual solubility of these phases in the solid state is low. Such borides are TiB2 and HfB2 in equilibrium with β-NiAl, and such carbides are, e.g., TiC and HfC in equilibrium with β-NiAl and La2C3, NbC, and TaC in equilibrium with γ'-Ni3Al. Natural composites II should be produced using solid-phase methods (NiAl with AlN, Y2O3, Al2O3) or a combination of methods, where a refractory interstitial phase of the Al2O3 or Y2O3 type is solid and the intermetallic NiAl or Ni3Al matrix is liquid. NiAl-TiB2 (HfB2), NiAl-Al2O3 (Y2O3), and Ni3Al-La2C3 (NbC, TaC) composites are considered as examples.

  6. Processing development of 4 tantalum carbide-hafnium carbide and related carbides and borides for extreme environments

    Science.gov (United States)

    Gaballa, Osama Gaballa Bahig

    Carbides, nitrides, and borides ceramics are of interest for many applications because of their high melting temperatures and good mechanical properties. Wear-resistant coatings are among the most important applications for these materials. Materials with high wear resistance and high melting temperatures have the potential to produce coatings that resist degradation when subjected to high temperatures and high contact stresses. Among the carbides, Al4SiC4 is a low density (3.03 g/cm3), high melting temperature (>2000°C) compound, characterized by superior oxidation resistance, and high compressive strength. These desirable properties motivated this investigation to (1) obtain high-density Al4SiC4 at lower sintering temperatures by hot pressing, and (2) to enhance its mechanical properties by adding WC and TiC to the Al4SiC4. Also among the carbides, tantalum carbide and hafnium carbide have outstanding hardness; high melting points (3880°C and 3890°C respectively); good resistance to chemical attack, thermal shock, and oxidation; and excellent electronic conductivity. Tantalum hafnium carbide (Ta4HfC 5) is a 4-to-1 ratio of TaC to HfC with an extremely high melting point of 4215 K (3942°C), which is the highest melting point of all currently known compounds. Due to the properties of these carbides, they are considered candidates for extremely high-temperature applications such as rocket nozzles and scramjet components, where the operating temperatures can exceed 3000°C. Sintering bulk components comprised of these carbides is difficult, since sintering typically occurs above 50% of the melting point. Thus, Ta4 HfC5 is difficult to sinter in conventional furnaces or hot presses; furnaces designed for very high temperatures are expensive to purchase and operate. Our research attempted to sinter Ta4HfC5 in a hot press at relatively low temperature by reducing powder particle size and optimizing the powder-handling atmosphere, milling conditions, sintering

  7. Atomphysik für Höhlenmenschen und andere Anfänger das Universum von innen : Moleküle, Atome und Elementarteilchen

    CERN Document Server

    Beetz, Jürgen

    2016-01-01

    Jürgen Beetz zeigt zuerst den Ursprung der erdachten Geschichten der Physik aus der Steinzeit, denn vieles ist so einfach, dass es schon Steinzeitmenschen hätten verstehen können. Im Anschluss daran erklärt der Autor den Aufbau von Atomen und sagt etwas zu ihren physikalischen Größen aus. Obwohl „Atom“ eigentlich „unteilbar“ bedeutet, bestehen Atome dennoch aus Teilen – dies erläutert er im Weiteren genau. Schließlich bespricht er die geheimnisvollen „Quanten“ und ihr merkwürdiges Verhalten.

  8. Lípidos en el anfípodo Talorchestia margaritae (Amphipoda: Talitridae y su relación con la ecología de la especie

    Directory of Open Access Journals (Sweden)

    Sandra López

    2010-09-01

    Full Text Available T. margaritae cumple un papel importante en la descomposición de restos vegetales y animales en las costas venezolanas. El objetivo fue determinar las diferencias en la composición lipídica entre sexos y talla de la especie. Para esto, especímenes de T. margaritae fueron recolectados en la zona supralitoral de dos playas arenosas: Mangle Quemao y las Mercedes de Paparo. Posteriormente se separaron por talla y sexo determinándoles su peso, densidad, biomasa y perfil lipídico. Todas las categorías presentaron tallas similares entre localidades. Los pesos fueron superiores en los organismos de Mangle Quemao. Los lípidos totales presentaron proporciones similares entre sexos, talla y localidad (3-5%, al igual que los fosfololípidos (20-30%, glicolípidos (Lipids in the amphipod Talorchestia margaritae (Amphipoda: Talitridae and its relationship with the ecology of the species. T. margaritae, an endemic species inhabiting Venezuelan coasts, plays an important ecological role in plant and animal decomposition. To understand this issue in some animal groups, especially small ones, lipid composition analysis has been an interesting tool to describe their trophic relationships and food preferences. In order to assess this and visualize the components of their diet, we determined the lipid composition differences between males and females and among age classes in this species. Two sandy beaches were selected: Mangle Quemao and Las Mercedes de Paparo, from which sand samples of known volume were collected at the supralittoral area in 2007. Organisms were separated by age and sex classes, and their size, weight, density, biomass, total lipids (TL, lipid classes and fatty acid markers present in their tissues were determined. The sizes were similar for all age classes between the two locations, while the weights were higher for Mangle Quemao. The TL and lipid classes showed similar proportions between sexes, age classes and locations (TL: 3-5%; Phospholipids: 20-30%; Glycolipids: <1%; sterols: 4%. On the other hand, Triglycerides (TAG were higher in Mangle Quemao, which may be related to the difference between the weights of two locations. The most abundant fatty acid biomarkers in the two studied sites were 16:0 and 18:1(n-9; this last one is characteristic of a carnivorous diet. The other nine markers were identified with changes in their distribution in organisms at Mangle Quemao and between males and females of both populations. Based on observed fatty acids markers we can assume T. margaritae as a generalist carnivore. Those populations were influenced by available food; inducing differences in weight, TAG proportion and markers diversity. Rev. Biol. Trop. 58 (3: 841-855. Epub 2010 September 01.

  9. Kosmologie für Höhlenmenschen und andere Anfänger das Universum von aussen : Trabanten, Planeten, Sterne, Galaxien

    CERN Document Server

    Beetz, Jürgen

    2016-01-01

    Jürgen Beetz zeigt zuerst den Ursprung der erdachten Geschichten der Physik aus der Steinzeit, denn vieles ist so einfach, dass es schon Steinzeitmenschen hätten verstehen können. Im Anschluss daran untersucht der Autor das Weltall auf seine Bestandteile: Monde, Planeten, Sterne, Galaxien usw. Daraus ergibt sich die Frage nach dessen Struktur und Dynamik: Ist das Universum ewig, endlos, konstant? Nichts davon: Es hat eine Entstehungsgeschichte, es expandiert und verändert sich – zum Teil aus noch ungeklärten Ursachen. Besonderes Augenmerk richtet er auf die Expansion des Weltalls und die sich daraus ergebenden Folgen.

  10. Market introduction of building automation systems: Pt. 2. Functions, emotions anf prestige; Markterschliessung von HausAutomations-Systemen. T. 2. Funktionen, Emotionen und Prestige

    Energy Technology Data Exchange (ETDEWEB)

    Jeck, M.S. [Roland Berger und Partner, International Management Consultants, Muenchen (Germany)

    1997-04-21

    After the introduction of a variety of components for intelligent building automation systems, marketing efforts for whole systems should now be enhanced. The author intends to make 7 statements on this subject, of which Nos. 2 and 3 are presented here. (orig.) [Deutsch] Aus dem intelligenten Haus einen Markt machen - aber wie? Nach einer ausfuehrlichen Betrachtung der Moeglichkeitewn moderner Haus-Automations-Systeme forderte der Autor bereits in der CCI-Serie (CCI 1/97) die Branche auf, sich nach der Markteinfuehrung eines breiten Programmes verschiedenster Haus-Automations-Komponenten nun verstaerkt dem Marketing und dem Vertrieb von Haus-Automations-Loesungen zuzuwenden. Zusammengefasst sind die damit verknuepften Aufgaben und Anforderungen in ``Sieben Thesen``, von denen nachfolgend die Thesen 2 und 3 behandelt werden (orig.)

  11. Lípidos en el anfípodo Talorchestia margaritae (Amphipoda: Talitridae y su relación con la ecología de la especie

    Directory of Open Access Journals (Sweden)

    Sandra López

    2010-09-01

    Full Text Available T. margaritae cumple un papel importante en la descomposición de restos vegetales y animales en las costas venezolanas. El objetivo fue determinar las diferencias en la composición lipídica entre sexos y talla de la especie. Para esto, especímenes de T. margaritae fueron recolectados en la zona supralitoral de dos playas arenosas: Mangle Quemao y las Mercedes de Paparo. Posteriormente se separaron por talla y sexo determinándoles su peso, densidad, biomasa y perfil lipídico. Todas las categorías presentaron tallas similares entre localidades. Los pesos fueron superiores en los organismos de Mangle Quemao. Los lípidos totales presentaron proporciones similares entre sexos, talla y localidad (3-5%, al igual que los fosfololípidos (20-30%, glicolípidos (<1% y esteroles (4%, exceptuando los triglicéridos (TAG, siendo estos superiores en Mangle Quemao. Esto último pudiendo estar relacionado con la diferencia de pesos entre localidades. Los ácidos grasos más abundantes en ambas localidades fueron 16:0 y 18:1(n-9. Se identificaron otros 9 marcadores con variaciones en su distribución. Con base en los biomarcadores se puede catalogar a T. margaritae como una especie carnívora- generalista, siendo sus poblaciones influenciadas por la disponibilidad de alimento que a su vez, podría inducir diferencias de peso, TAG y biomarcadores.

  12. Riqueza, distribuição sazonal e utilização de habitats por anfíbios anuros na Serra do Brigadeiro, Minas Gerais

    OpenAIRE

    Assis, Breno de

    2009-01-01

    A estrutura de comunidades de anuros pode ser avaliada tanto quantitativamente, através das relações espécie-área, como qualitativamente, através do registro das espécies presentes nas assembléias e suas distribuições no tempo e espaço. Neste estudo, realizado entre agosto de 2007 a julho de 2008, verificou-se a existência de padrões de riqueza, distribuição temporal e ocupação de habitats por anuros em duas lagoas e dois riachos no Parque Estadual da Serra do Brigadeiro, PESB, (20°43 S, 42°2...

  13. Domestic Research Process of Matrix Modification for Carbon/Carbon Composites%国内C/C复合材料基体改性研究进展

    Institute of Scientific and Technical Information of China (English)

    付前刚; 李贺军; 沈学涛; 李克智

    2011-01-01

    Oxidation and ablation of carbon/carbon (C/C) composites in oxidation-containing environments limits their applications as the high-temperature structural materials in aeronautics and aerospace fields. Matrix modification is an effective method for protecting C/C composites against oxidation and ablation at high temperature. The methods for matrix modification, including chemical vapor infiltration, precursor infiltration pyrolysis, reactive melt infiltration and chemical vapor reaction, were introduced. The research status of several modification materials, including SiC, ZrC, TaC, HfC, ZrB2, WC and Cu, were reviewed. Refractory carbides or borides, such as HfC, ZrC, TaC, HfB2 and ZrB2, characterized by high melting point, excellent stability and ablation resistance at high temperature, are the perfect candidates for modifying C/C composites. The present problems and the potential development direction on the investigation of matrix modification for C/C composites were also proposed.%碳/碳(C/C)复合材料在高温含氧气氛下的氧化烧蚀问题严重制约该材料在航空航天领域的推广应用,基体改性技术是提高该材料高温抗氧化抗烧蚀能力的有效手段。介绍了目前发展的化学气相渗透、先驱体转化、反应熔体浸渗、化学气相反应等基体改性技术的主要方法,综述了SiC,ZrC,TaC,HfC,ZrB2,WC,Cu等抗氧化和抗烧蚀组元改性C/C复合材料的研究现状。指出难熔金属碳化物和硼化物,如HfC,ZrC,TaC,HfB2,ZrB2等,具有熔点高、高温性能稳定、抗烧蚀性能优良等特点,是提高C/C复合材料高温抗氧化抗烧蚀的理想基体改性材料,并提出了C/C复合材料基体改性研究中存在的问题和今后潜在的发展方向。

  14. Data of evolutionary structure change: 1ANFA-2FNCA [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available EVID> 0 1ANF A EVID>EVID> 1 1ANF...1ANFA-2FNCA 1ANF 2FNC A A KIEEGKLVIWINGDKGYNGLAEVGKKFEKDTGIKVTVEH...SIKSKFLTAAPQGQGADIIVGAHDWVGELAVNGLIEPIP-NFSDLKNFYDTALKAFSYGGKLYGVPYAMEAVALIYNKDYVDSVPKTMDELIEKAKQIDEEYGGEVRGFIYDVANF...GLWAIKSYKDAGINYGVAPIPELEPGVPAKPFVGVQGFMINAKSPNKVIAMEFLTNFIARKETMYKIYLADP-RLPARKDVLELVKDNPDVVAFTQSASMGTPMPNVP

  15. Technical files. The HFC refrigerating fluids, the R 22 substitutes devoted to air conditioning; Fiches Techniques. Les fluides frigorigenes HFC, substituts du R 22 destines au conditionnement d`air

    Energy Technology Data Exchange (ETDEWEB)

    Guilpain, G. [Elf Atochem, 92 - Paris le Defense (France)

    1998-05-01

    Following the Montreal (Canada) protocol for the regulation of ozone destructive products, the air conditioning professionals have carried out a research work on possible substitutes to CFCs and HCFCs. The R 134a, R 407C and R 410A are todays standards defined for the replacement of the R 22. The R 134a is devoted to air conditioning systems of the industrial and tertiary sectors (> 250 kW), the R 407C concerns the residential and tertiary sectors, while the R 410A is under development for the domestic and residential systems (2-3 kW). The choice for a given substitute depends on regulatory, safety and technical criteria which are recalled in this paper. (J.S.)

  16. Atmospheric chemistry of HFC-134a. Kinetic and mechanistic study of the CF3CFHO2 + NO2 reaction

    DEFF Research Database (Denmark)

    Møgelberg, T.E.; Nielsen, O.J.; Sehested, J.;

    1994-01-01

    A pulse radiolysis system was used to study the kinetics of the reaction of CF3CFHO2 with NO2. By monitoring the rate of the decay of NO2 using its absorption at 400 nm the reaction rate constant was determined to be k = (5.0 +/- 0.5) x 10(-12) cm3 molecule-1 s-1. A long path length Fourier......-transform infrared technique was used to investigate the thermal decomposition of the product CF3CFHO2NO2. At 296 K in the presence of 700 Torr of air, decomposition of CF3CFHO2NO2 was rapid (greater than 90% decomposition within 3 min). The results are discussed in the context of atmospheric chemistry of CF3CFH2...

  17. Research and Implementation of Multicast Technology in HFC%HFC网络组播技术研究与实现

    Institute of Scientific and Technical Information of China (English)

    王沁; 袁玲玲; 张燕; 许娜; 李翀

    2009-01-01

    A network access device (CM) based on DOCSIS 1.1 must suppress multicast traffic. The CM controls the forwarding of multicast by administratively setting parameters for the policy-filter service and by a specific multicast tracking algorithm, and the latter includes the passive IGMP mode and active IGMP mode. According to the demands of the passive IGMP mode and the characteristic that CM has a fixed host port and a fixed router port, a Data-Over-Cable IGMP Snooping protocol was designed and implemented. The protocol works on the MAC Layer, can snoop ICMP packets received by CM, maintains a list of multicast groups and can filter multicast data. The new protocol was tested in the bidirectional system platform for HDTV( High Definition Television), which consists of a self-developed PHY and MAC chip.%符合DOCSIS1.1规范的网络接入设备CM需要抑制组播.这种CM使用两种机制控制组播的转发,即设置策略过滤业务参数和专门的组播跟踪算法,而后者有passive IGMP和active IGMP两种模式.根据passive IGMP的要求和CM有固定的主机端口和固定的路由器端口的特点,设计并实现了一种电缆网络IGMP Snooping协议.该协议运行在MAC层,实现侦听CM收到的IGMP报文、维护组播组列表、过滤组播数据的功能.本设计在自主开发的物理层和MAC层芯片组成的HDTV(高清晰度电视)双向系统平台进行测试.

  18. Ultra-Refractory Composites for Propulsion Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This phase I research proposes an efficient approach to develop a reliable chemical vapor infiltration (CVI) process for HfB2-HfC-SiC matrices for carbon fiber...

  19. Preparation of Oxidation-Resistant Ultra High Melting Temperature Materials and Structures Using Laser Method

    Science.gov (United States)

    2009-06-06

    other UHTCs like hafnium diboride (HfB2) and refractory metals such as rhenium and tungsten. In addition, these ceramic-metal composites (cermets...performance at much lower densities compared to other widely studied UHTC materials like hafnium diboride (HfB2) and current nozzle materials such as...free part. Electron beam sintering technique is primarily limited to conductive materials like metals and their alloys so that the electron charge

  20. Mechanical Testing of Ultra-High Temperature Ceramics at 1500 C in Air - Development of an Experimental Facility and Test Method

    Science.gov (United States)

    2015-03-26

    A) and HfO2 + 4B → HfB2 + B2O2 (borothermal) (B) The reduction processes are highly endothermic . For example, carbothermal...formation of oxide impurities. Furthermore, Rxns. D and E are highly exothermic and favorable at all temperatures. If the reaction is allowed to proceed...analysis (TEM) was unable to definitively determine the composition of the Pt alloy that infiltrated the HfB2 grain boundaries in this test

  1. Diversidade cariotípica e molecular de Leptodactylus (Anura, Leptodactylidae) e obtenção de sondas cromossomo-específicas de anfíbio por citometria de fluxo

    OpenAIRE

    Gazoni, Thiago [UNESP

    2015-01-01

    The genus Leptodactylus currently has 74 recognized species in the Neotropical Region, of which 57 were reported in Brazil. Factors such as high morphological similarity, as well as the lack of diverse data from different populations, result in the confusing taxonomic status of some species in the genus. Advances in this matter were obtained by increasing studies involving mainly comparison of molecular data, but often are not examined specimens collected in the type localities, fundamental f...

  2. Reproductive modes and fecundity of an assemblage of anuran amphibians in the Atlantic rainforest, Brazil Modos reprodutivos e fecundidade de anfíbios anuros em uma taxocenose na Mata Atlântica, Brasil

    Directory of Open Access Journals (Sweden)

    Marilia T Hartmann

    2010-09-01

    Full Text Available Reproductive modes and size-fecundity relationships are described for anurans from Picinguaba, a region of Atlantic rainforest on the northern coast of the state of São Paulo, Brazil. We observed 13 reproductive modes, confirming a high diversity of modes in the Atlantic rainforest. This diversity of reproductive modes reflects the successful use of diversified and humid microhabitats by anurans in this biome. We measured the snout-vent length of 715 specimens of 40 species of anurans. The size-fecundity relationship of 12 species was analyzed. Female snout-vent lengths explained between 57% and 81% of clutch size variation. Anurans with aquatic modes laid more eggs than those with terrestrial or arboreal modes. Larger eggs were deposited by species with specialized reproductive modes.Neste estudo são apresentados os modos reprodutivos e as relações de tamanho-fecundidade dos anuros encontrados em Picinguaba, uma região de Mata Atlântica no litoral norte do estado de São Paulo. Foram registrados 13 modos reprodutivos, confirmando a alta diversidade de modos reprodutivos encontrados na Mata Atlântica. A diversidade de modos reprodutivos observados na Mata Atlântica é o resultado do sucesso dos anuros na utilização dos diversos microhábitats úmidos desse bioma. Os comprimentos rostro-cloacais de 715 indivíduos de 40 espécies de anuros foram medidos. Foram consideradas as relações de tamanho-fecundidade para 12 espécies. O tamanho do corpo explicou entre 57% e 81% da variação no tamanho da ninhada. Os modos reprodutivos aquáticos apresentaram maior número de ovos, comparados aos modos reprodutivos terrestres ou arborícolas. As espécies com maior tamanho de ovos foram as que apresentaram modos reprodutivos especializados.

  3. Primer registro e histología básica del anfípodo terrestre Talitroides topitotum (Amphipoda: Talitridae), introducido en las zonas montañosas de Heredia, Costa Rica

    OpenAIRE

    Alfaro Montoya, Jorge; Umaña Castro, Rodolfo

    2013-01-01

    This study documents for the first time the introduction of the terrestrial amphipod, Talitroides topitotum (Talitridae) to mountain regions of San Rafael and Barva, Heredia, Costa Rica, with predominance of juveniles and adult females with and without eggs. The species comes from Asia and could have been introduced associated with exotic plants. Basic aspects of histology are described, including the cellular structure of the main organs: heart, intestine, hepatopancreas, ovary, nerve cord, ...

  4. La pez y la impermeabilización de envases anfóricos romanos. Estudio analítico de una muestra e interpretaciones histórico-económicas

    Directory of Open Access Journals (Sweden)

    Martínez Maganto, Julio

    1998-12-01

    Full Text Available The nature and purpose of pitch is examined on the basis of a sample taken from the inner wall of an early imperial fish-sauce amphora. The study seeks to identify the source of the pitch and its precise composition. Questions concerning the product's manufacture and its commercial applications are considered as part of a discussion of its contribution to the Roman economy.A partir del análisis químico de una muestra de la pez que recubre las paredes internas de un ánfora de salazón altoimperial romana, se realiza un estudio sobre las características y funcionalidad de esta sustancia. El objetivo perseguido es clarificar el origen y exacta naturaleza de la misma, además de aportar algunos elementos de debate sobre su producción y posible comercialización, analizando su importancia en el contexto de la economía romana.

  5. Diversidade de anfíbios anuros de uma área de Pampa no município de São Gabriel, Rio Grande do Sul, Brasil

    Directory of Open Access Journals (Sweden)

    Ana Maria R. Bolzan

    2014-09-01

    Full Text Available Considerado um bioma ameaçado, o Pampa possui um dos menores percentuais de área legalmente protegida. Além disso, o conhecimento sobre comunidades de anuros neste bioma ainda é escasso. Nesse contexto, o objetivo deste estudo foi determinar a composição de anuros em uma área de Pampa no sul do Brasil. Entre janeiro de 2009 e fevereiro de 2010 foi realizado um inventário na Fundação Estadual de Pesquisa Agropecuária do município de São Gabriel, Rio Grande do Sul. A procura dos exemplares foi realizada em poças permanentes, semi-permanentes e temporárias pelo método de levantamento em sítio de reprodução. Foram registradas 21 espécies pertencentes a cinco famílias, o que corresponde a aproximadamente 20% das espécies do estado e 42% das espécies conhecidas para a ecorregião Savana Uruguaia. Dez espécies foram consideradas frequentes, sete comuns e quatro foram raras. Foram registrados três modos reprodutivos, sendo que 57% das espécies utilizam o modo 1, que parece estar relacionado à homogeneidade da área. A análise de agrupamento comparando a composição de anuros de quatro localidades distintas mostrou maior similaridade com o município de Candiota (região da Campanha. As espécies presentes na área de estudo são associadas a formações campestres do estado e países vizinhos e podem ser consideradas típicas do bioma Pampa.

  6. Efectos de la contaminación por metales pesados sobre anfípodos de agua dulce y su aplicación en estudios de toxicidad de sedimentos

    OpenAIRE

    Giusto, Anabella

    2015-01-01

    Las evaluaciones ecotoxicológicas son herramientas fundamentales en las estimaciones de riesgo ambiental y la toma de decisiones de políticas de control y prevención de daños ecológicos. A nivel regional la caracterización ecotoxicológica de sedimentos se determina principalmente evaluando en ellos niveles de contaminantes considerados como prioritarios, sin tener en cuenta factores tales como biodisponibilidad, resuspensión posibles interacciones o impacto sobre estructura y funcionamiento d...

  7. 基于HFC网络的Internet接入方案设计%Scheme Design of Internet Access Based on HFC Network

    Institute of Scientific and Technical Information of China (English)

    蔡方凯

    2004-01-01

    利用目前CATV网络的闲置频带和覆盖面广的优势,通过CATV网络接入Internet是一种有效的方法.基于HFC网络的Internet接入方案是在不改造原网络的前提下,利用成熟的ADSL技术,是一种投资少、见效快、性能优的Internet接入方案.

  8. 40 CFR Appendix C to Subpart B of... - SAE J2788 Standard for Recovery/Recycle and Recovery/Recycle/Recharging Equipment for HFC-134a...

    Science.gov (United States)

    2010-07-01

    ... Part 82 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... refrigerant into systems with various lubrication types and shall deliver less than 1% by weight residual...

  9. 40 CFR Appendix D to Subpart B of... - SAE J2810 Standard for Recovery Only Equipment for HFC-134a Refrigerant

    Science.gov (United States)

    2010-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) PROTECTION OF STRATOSPHERIC OZONE Servicing... of new lubricant is returned to the mobile A/C system for compressor lubrication, if the system is...

  10. Defining the Binding Region in Factor H to Develop a Therapeutic Factor H-Fc Fusion Protein against Non-Typeable Haemophilus influenzae.

    Science.gov (United States)

    Wong, Sandy M; Shaughnessy, Jutamas; Ram, Sanjay; Akerley, Brian J

    2016-01-01

    Non-typeable Haemophilus influenzae (NTHi) cause a range of illnesses including otitis media, sinusitis, and exacerbation of chronic obstructive pulmonary disease, infections that contribute to the problem of antibiotic resistance and are themselves often intractable to standard antibiotic treatment regimens. We investigated a strategy to exploit binding of the complement inhibitor Factor H (FH) to NTHi as a functional target for an immunotherapeutic containing the NTHi binding domain of FH fused to the Fc domain of IgG1. Chimeric proteins containing the regions that most FH-binding bacteria use to engage human FH, domains 6 and 7 (FH6,7/Fc) and/or 18 through 20 (FH18-20/Fc), were evaluated for binding to NTHi. FH6,7/Fc bound strongly to each of seven NTHi clinical isolates tested and efficiently promoted complement-mediated killing by normal human serum. FH18-20/Fc bound weakly to three of the strains but did not promote complement dependent killing. Outer-membrane protein P5 has been implicated in FH binding by NTHi, and FH6,7/Fc binding was greatly diminished in five of seven P5 deficient isogenic mutant strains tested, implicating an alternative FH binding protein in some strains. Binding of FH18-20/Fc was decreased in the P5 mutant of one strain. A murine model was used to evaluate potential therapeutic application of FH6,7/Fc. FH6,7/Fc efficiently promoted binding of C3 to NTHi exposed to mouse serum, and intranasal delivery of FH6,7/Fc resulted in significantly enhanced clearance of NTHi from the lung. Moreover, a P5 deficient mutant was attenuated for survival in the lung model, suggesting that escape mutants lacking P5 would be less likely to replace strains susceptible to FH6,7/Fc. These results provide evidence for the potential utility of FH6,7/Fc as a therapeutic against NTHi lung infection. FH binding is a common property of many respiratory tract pathogens and FH/Fc chimeras may represent promising alternative or adjunctive therapeutics against such infections, which are often polymicrobial.

  11. Strain Hardening Cement Composites Structural Design and Performance State-of-the-Art Report of the RILEM Technical Committee 208-HFC, SC3

    CERN Document Server

    Kanda, Tetsushi

    2013-01-01

    Strain Hardening Cement Composites, SHCC hereafter, demonstrate excellent mechanical behavior showing tensile strain hardening and multiple fine cracks. This strain hardening behavior improves the durability of concrete structures employing SHCC and the multiple fine cracks enhance structural performance. Reliable tensile performance of SHCC enables us to design structures explicitly accounting for SHCC’s tensile properties. Reinforced SHCC elements (R/SHCC) indicate large energy absorbing performance under large seismic excitation. Against various types of loads, R/SHCC elements can be designed by superimposing re-bar performance and SHCC’s tensile performance.  This report focuses on flexural design, shear design, FE modeling and anti-seismic design of R/SHCC elements as well as application examples.  Establishing design methods for new materials usually leads to exploring application areas and this trend should be demonstrated by collecting actual application examples of SHCC in structures.

  12. Viscosity measurements and correlations of binary mixtures: 1,1,1,2-tetrafluoroethane (HFC-134a)+tetraethylene glycol dimethylether (TEGDME)

    DEFF Research Database (Denmark)

    Monsalvo, Matias Alfonso; Baylaucq, A.; Reghem, P.;

    2005-01-01

    and pure TEGDME (both previously studied at the laboratory), have been correlated using several viscosity models (mixing rules, self-refrencing model, hard-sphere theory, friction theory and free volume model). The resulting models are presented and discussed in this work. (c) 2005 Elsevier B.V. All rights...

  13. R245fa传热特性的实验研究%Experimental Study on Evaporating Heat Transfer Characteristics of HFC-245fa

    Institute of Scientific and Technical Information of China (English)

    黄晓艳; 王华; 王辉涛

    2011-01-01

    对R245fa水平光滑管管内流动沸腾换热特性进行了实验研究,主要包括加热水质量流速、工质质量流速、蒸发温度以及干度对局部换热系数的影响,结果表明在相同蒸发温度及加热水质量流速下,随着工质质量流速增大,管内流动沸腾换热系数迅速升高;在相同工质质量流速及蒸发温度下,随着加热水质量流速的增大,管内流动沸腾换热系数升高;在相同工质质量流速及加熟水质量流速下,随着蒸发温度的升高,管内流动沸腾换热系数降低.分别采用Chen公式、Liu-Winterton公式、Shah公式计算了与本实验相同工况下R245fa的管内流动沸腾换热系数,其结果表明:3个预测公式的计算结果与实验值之间的平均误差分别为31.6%、6.3%、37.4%.采用Liu-Winterton公式计算R245fa的流动沸腾换热系数满足工程实际的要求.%Convective boiling heat transfer characteristics of R245fa inside horizontal tube are investigated at various mass flow rates of hot water, working fluids and at various evaporation temperatures. The investigation results show that convective boiling heat transfer coefficients goes up with the increase of hot water and working fluid mass flow rate, but it is contrary to evaporation temperature. By comparisons of the experimental local heat transfer coefficients with that predicted by Chen correlation, Liu-Winterton correlation and Shah correlation, it is concluded that deviations of these three correlations are 31.6 %、 6.3 %、37.4 % respectively. Liu-Winterton correlation is more precise to predict convective boiling heat transfer coefficients of R245fa than Chen correlation and Shah correlation.

  14. Defining the binding region in factor H to develop a therapeutic factor H-Fc fusion protein against nontypeable Haemophilus influenzae

    Directory of Open Access Journals (Sweden)

    Sandy M. Wong

    2016-04-01

    Full Text Available Nontypeable Haemophilus influenzae (NTHi cause a range of illnesses including otitis media, sinusitis, and exacerbation of chronic obstructive pulmonary disease, infections that contribute to the problem of antibiotic resistance and are themselves often intractable to standard antibiotic treatment regimens. We investigated a strategy to exploit binding of the complement inhibitor Factor H (FH to NTHi as a functional target for an immunotherapeutic containing the NTHi binding domain of FH fused to the Fc domain of IgG1. Chimeric proteins containing the regions that most FH-binding bacteria use to engage human FH, domains 6 and 7 (FH6,7/Fc and/or 18 through 20 (FH18-20/Fc, were evaluated for binding to NTHi. FH6,7/Fc bound strongly to each of seven NTHi clinical isolates tested and efficiently promoted complement-mediated killing by normal human serum. FH18-20/Fc bound weakly to three of the strains but did not promote complement dependent killing. Outer-membrane protein P5 has been implicated in FH binding by NTHi, and FH6,7/Fc binding was greatly diminished in five of seven P5 deficient isogenic mutant strains tested, implicating an alternative FH binding protein in some strains. Binding of FH18-20/Fc was decreased in the P5 mutant of one strain. A murine model was used to evaluate potential therapeutic application of FH6,7/Fc. FH6,7/Fc efficiently promoted binding of C3 to NTHi exposed to mouse serum, and intranasal delivery of FH6,7/Fc resulted in significantly enhanced clearance of NTHi from the lung. Moreover, a P5 deficient mutant was attenuated for survival in the lung model, suggesting that escape mutants lacking P5 would be less likely to replace strains susceptible to FH6,7/Fc. These results provide evidence for the potential utility of FH6,7/Fc as a therapeutic against NTHi lung infection. FH binding is a common property of many respiratory tract pathogens and FH/Fc chimeras may represent promising alternative or adjunctive therapeutics against such infections, which are often polymicrobial.

  15. Pension

    DEFF Research Database (Denmark)

    Hougaard Jensen, Svend E.; Hansen, Jan V.

    2013-01-01

    Analyse. Det danske system med arbejdsmarkedspensioner er under pres - anført af politikerne og ' tidsånden'.......Analyse. Det danske system med arbejdsmarkedspensioner er under pres - anført af politikerne og ' tidsånden'....

  16. Data of evolutionary structure change: 1ANFA-3F5FA [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1ANFA-3F5FA 1ANF 3F5F A A KIEEGKLVIWINGDKGYNGLAEVGKKFEKDTGIKVTVEH...TGKKSHLRKTTEKKLPTAATIAKLQQSEIWKMENEFYEFALEQFQFVRAHAVREKDGELYILAQNFFYEKIYPK...HHHHHHHHHHHHH EEEEE EEE EVID> 0 1ANF A 1ANFA 3.7251410484313965 EVID>EVID> 1 <

  17. Data of evolutionary structure change: 1ANFA-2GHAA [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 958 EVID> 1 1ANF...1ANFA-2GHAA 1ANF 2GHA A A KIEEGKLVIWINGDKGYNGLAEVGKKFEKDTGIKVTVEH...PNIPQMSAFWYAVRTAVINAASGRQTVDEALKDAQTRITK--- --MQPKLTIWCSEKQ-VDILQKLGEEFKAKYGVEVEVQYVNFQDIKSKFLT...AAPEGQGADIIVGAHDWVGELAVNGLIEPIPNF-SDLKNFYETALNAFSYGGKLYGIPYAMEAIALIYNKDYVPEPPKTMDELIEIAKQIDEEFGGEVRGFITSAAEF...EEEHHHHHHHH HHHHHHHHHGGG HHHHHHHHHHHHHHH HHHHHHHHHHHHHHH

  18. Vergelijking van drie soja-eiwitten (Soycomil P, HP300 en LodeStar ProFa) in biggenvoeders

    NARCIS (Netherlands)

    Rodenburg, T.B.; Krimpen, van M.M.; Binnendijk, G.P.; Bruininx, E.M.A.M.; Mulder, A.

    2004-01-01

    Sojaschroot bevat bepaalde antinutritionele factoren (ANF's), waardoor men deze grondstof beperkt kan opnemen in voeders voor jonge biggen. Door ontvette sojaflakes een specifieke behandeling te geven is het mogelijk het ANF-gehalte te verlagen of de effecten van ANF's te verminderen, zodat een

  19. 电热水器用环戊烷/HFC-245 fa型聚氨酯硬泡组合聚醚的研究%Study on Cyclopentane/HFC-245fa Blown Rigid Polyurethane Foam Premixed Polyol for Electric Water-Heater

    Institute of Scientific and Technical Information of China (English)

    贾雪芹; 赵路; 李明; 信延垒

    2016-01-01

    With polyether polyols, iscoyanate, foam stabilizer, catalyst and foaming agent as raw materials, the blown rigid polyurethane foam for electric water⁃heater was prepared. The influence of types and composition of raw materials on thermal insulation performance of electric water⁃heater was discussed and formulation system was optimized. The results showed that the polyurethane foam thermal conductivity was 18�8 mW/(m·K), high and low temperature change rate was less than 0�2% when the mass ratio of cyclopentane and HFC⁃245fa was 2�1. The properties of polyurethane foam could reach the specification requirement of electric water⁃heater product.%以聚醚多元醇、异氰酸酯、泡沫稳定剂、催化剂和发泡剂等为原料,制备了电热水器用聚氨酯硬泡组合聚醚,探讨了原料种类和组成对电热水器保温性能的影响,优化了配方体系。结果表明,选择环戊烷与HFC⁃245fa的质量比值为2�1,得到的聚氨酯硬泡导热系数为18�8 mW/( m·K),高/低温尺寸变化率均小于0�2%,可满足电热水器产品的使用要求。

  20. CF3CH2CF2CH3(HFC-365mfc)与Cl原子反应的微观机理及动力学性质%Mechanism and Kinetics for Reaction of CF3CH2CF2CH3(HFC-365mfc) with Cl Atom

    Institute of Scientific and Technical Information of China (English)

    金铜音; 王钦; 刘靖尧

    2013-01-01

    采用密度泛函理论方法M06-2X结合6-31+G(d,p)基组研究了CF3 CH2 CF2 CH3与Cl原子反应的反应机理.计算获得了CF3 CH2 CF2 CH3的两种可区分的稳定几何构象RC1和RC2以及与它们相对应的8条氢提取反应通道和2条取代反应通道.运用改进的正则变分过渡态理论(ICVT)并结合小曲率隧道效应校正(SCT),在M06-2X/6-31 +G(d,p)水平上计算了各氢提取通道的速率常数,并由Bohzmann配分函数得到总包反应的速率常数kT(cm3-molecule-1·s-1).计算结果表明,体系的总反应速率常数与已有实验值相吻合,进而给出了该反应在200~1000 K温度区间内反应速率常数κT的三参数表达式kT=1.88×10-22T3.76·exp(-1780.69/T),并讨论了两种构象RC1和RC2对总反应的贡献及各构象中氢提取发生在-CH3或-CH2-基团上的位置选择性.此外,由于缺少相关反应物及产物自由基标准生成焓△Hf,298K的数据,利用等化学键法估算了在上述物种的标准生成焓.%The mechanism of the CF3CH2CF2CH3+C1 reaction was investigated by the M06-2X method combining with the 6-31+G(d,p) basis set[ M06-2X/6-31+G(d,p) ]. There were two distinguishable stable con-formers (RC1 and RC2) for the reactant CF3CH2CF2CH3, and eight H-abstraction channels as well as two substitution channels were located associated with them. The rate constants for each of the H-abstraction channels were evaluated by the improved canonical variational transition state theory (ICVT) with the small-curvature tunneling(SCT) approximation at the M06-2X/6-31+G(d,p) level. The overall rate constant(kT) was obtained by considering the weight factor of each conformer from the Boltzmann distribution function, and the calculated values agree well with the available experimental values. Moreover, the contribution of the two con-formers to the whole reaction as well as the site selectivity for each of the conformers were discussed. A three-parameter rate constant-temperature expression for the total reaction within 200-1000 K was fitted to kT = 1. 88×l0-22T3.76exp( -1780. 69/T). In addition, because of the lack of available experimental data for the reactant as well as the corresponding product radicals involved in the reactions, their enthalpies of the formation (△Hf,298K) were predicted via isodesmic reaction at the M06-2X/6-31+G(d,p) level.

  1. Response of atrial natriuretic factor to acute extracellular fluid volume in patients with pheochromocytoma.

    Science.gov (United States)

    Paniagua, R; Rodríguez, E; Amato, D; Sánchez, G; Ron, O; Rodríguez, F; Herrera-Acosta, J

    2000-01-01

    Patients with pheochromocytoma have been reported to show high plasmatic atrial natriuretic factor (ANF) levels. Its source may not be the atrium because blood volume, the most important physiological stimulus for ANF release, is usually reduced in these patients. To evaluate ANF secretion functional integrity, we studied three patients with pheochromocytoma before and after surgical removal of the tumor. Extracellular fluid (ECF) volume, plasmatic ANF levels, and plasmatic renin activity (PRA) were measured. ANF was measured before and after an acute saline load of 1.5L in 90 min. Before surgery, ECF volume was normal or reduced, and PRA was normal but decreased after the saline load. By contrast, ANF was elevated and did not change after the saline load. After surgery ANF decreased, ECF volume rose, and the saline load induced a significant increase of plasma ANF and reduction of PRA. ANF was present in significant amounts in tumoral tissue homogenates. These data suggest that the tumor was the source of ANF in these patients with pheochromocytoma because high levels of ANF, despite reduced or normal ECF volume, as well as unresponsiveness to acute saline infusion, were found before surgery with subsequent normalization after tumor removal.

  2. Immunoreactive atrial natriuretic factor is increased in ovine model of endotoxemia

    Energy Technology Data Exchange (ETDEWEB)

    Lubbesmeyer, H.J.; Woodson, L.; Traber, L.D.; Flynn, J.T.; Herndon, D.N.; Traber, D.L. (Univ. of Texas Medical Branch, Galveston (USA) Thomas Jefferson Medical College, Philadelphia, PA (USA) Westfaelian Wilhelms Univ., Muenster (West Germany))

    1988-04-01

    A bolus of Escherichia coli endotoxin (1.5 {mu}g/kg) was administered to chronically instrumented sheep. Immunoreactive atrial natriuretic factor (IR-ANF) was measured in extracted plasma by radioimmunoassay. There was a thirteenfold increase in IR-ANF 2 h after endotoxin administration, and IR-ANF levels remained significantly elevated during the first 6 h. A marked diuresis and natriuresis occurred between 4 and 6 h. ANF not only affects renal function but is also associated with decreased cardiac output, increased peripheral resistance (in sheep), and decreased capillary absorption (in rats). These renal and hemodynamic changes are also characteristic of the early (first 6 h) response to endotoxin. Therefore ANF should be considered as a potential mediator of renal and hemodynamic changes induced by sepsis. It is difficult to determine if ANF elevation is an epiphenomenon or a causative factor, because no antagonist of ANF is currently available.

  3. Microstructural characterization of as-cast hf-b alloys

    Directory of Open Access Journals (Sweden)

    João Carlos Jânio Gigolotti

    2012-04-01

    Full Text Available An accurate knowledge of several metal-boron phase diagrams is important to evaluation of higher order systems such as metal-silicon-boron ternaries. The refinement and reassessment of phase diagram data is a continuous work, thus the reevaluation of metal-boron systems provides the possibility to confirm previous data from an investigation using higher purity materials and better analytical techniques. This work presents results of rigorous microstructural characterization of as-cast hafnium-boron alloys which are significant to assess the liquid composition associated to most of the invariant reactions of this system. Alloys were prepared by arc melting high purity hafnium (minimum 99.8% and boron (minimum 99.5% slices under argon atmosphere in water-cooled copper crucible with non consumable tungsten electrode and titanium getter. The phases were identified by scanning electron microscopy, using back-scattered electron image mode and X-ray diffraction. In general, a good agreement was found between our data and those from the currently accepted Hafnium-Boron phase diagram. The phases identified are αHfSS and B-RhomSS, the intermediate compounds HfB and HfB2 and the liquide L. The reactions are the eutectic L ⇔ αHfSS + HfB and L ⇔ HfB2 + B-Rhom, the peritectic L + HfB2 ⇔ HfB and the congruent formation of HfB2.

  4. Process technological effects of deletion and amplification of hydrophobins I and II in transformants of Trichoderma reesei.

    Science.gov (United States)

    Bailey, M J; Askolin, S; Hörhammer, N; Tenkanen, M; Linder, M; Penttilä, M; Nakari-Setälä, T

    2002-05-01

    Transformants of the Trichoderma reeseistrains QM9414 and Rut-C30 were constructed in which the genes for the two major hydrophobin proteins, hydrophobins I (HFBI) and II (HFBII), were deleted or amplified by molecular biological techniques. Growth parameters and foam production of the transformant strains were compared with the corresponding properties of the parent strains by cultivation in laboratory bioreactors under conditions of catabolite repression (glucose medium) or induction of cellulolytic enzymes and other secondary metabolites (cellulose and lactose media). All the transformed strains exhibited vegetative growth properties similar to those of their parent. The Delta hfb2 (but not the Delta hfb1) transformant showed reduced tendency to foam, whereas both strains overproducing hydrophobins foamed extensively, particularly in the case of HFBII. Enzyme production on cellulose medium was unaltered in the Delta hfb2 transformant VTT D-99676, but both the Delta hfb2 and HFBII-overproducing transformants exhibited somewhat decreased enzyme production properties on lactose medium. Production of HFBI by the multi-copy transformant VTT D-98692 was almost 3-fold that of the parent strain QM9414. Overproduction of HFBII by the transformant VTT D-99745, obtained by transformation with three additional copies of the hfb2 gene under the cbh1 promoter, was over 5-fold compared to production by the parent strain Rut-C30. The Delta hfb2transformant VTT D-99676 produced a greatly increased number of spores on lactose medium compared with the parent strain, whereas the HFBII-overproducing transformant VTT D-99745 produced fewer spores.

  5. Theoretical studies on new refrigerant in refrigeration system for freeze and cold storage%用于冷冻冷藏制冷系统的新型制冷剂的理论研究

    Institute of Scientific and Technical Information of China (English)

    高赞军; 徐英杰; 仇宇; 李鹏; 韩晓红; 陈光明

    2012-01-01

    综述在冷冻冷藏系统中制冷剂替代研究的现状.在此基础上,提出一种新的混合制冷剂(HFG-161/HFC-125/HFC-143a,15/45/40)用于替代HFC-404A,该新型制冷剂的ODP为零,GWP比HFC-404A和R507A要小,其基本热力学性能与HFC-404A相近.对新型混合制冷剂和HFC-404A的循环性能进行理论分析与比较.结果表明,新型混合制冷剂的性能要比HFC-404A优越,环境性能更好,是HFC-404A潜有力的替代制冷剂.%The research status on refrigerant substitute for the freeze and cold storage system is reviewed. Based on this,a new ternary non-azeotropic mixture of HFC-161/HFC-125/HFC-143a( 15/45/40) as a promising mixed refrigerant to HFO404A is presented. The ODP of the new refrigerant is zero and its basic thermodynamic properties are similar to those of HFC-404A,and its GWP is much smaller than that of R507A or HFC-404A. The cycle performance between the new mixture refrigerant and HFC-404A is theoretically analyzed and compared. The results show that the cycle performance and environmental performance of the new mixture refrigerant are better than those of HFC-404A. The new mixture refrigerant may be a promising alternative refrigerant for HFC-404A.

  6. Atrial natriuretic factor: radioimmunoassay and effects on adrenal and pituitary glands

    Energy Technology Data Exchange (ETDEWEB)

    Gutkowska, J.; Horky, K.; Schiffrin, E.L.; Thibault, G.; Garcia, R.; De Lean, A.; Hamet, P.; Tremblay, J.; Anand-Srivastava, M.B.; Januszewicz, P.

    1986-06-01

    A simple and sensitive radioimmunoassay was developed for measurement of immunoreactive atrial natriuretic factor (IR-ANF) in rat and human plasma and in rat atria. The two atria contain about 20 ..mu..g ANF per rat. The right atrium contained 2.5 times more ANF than did the left. Ether anesthesia and morphine markedly increased IR-ANF in rat plasma. The concentration of IR-ANF in plasma of clinically normal human subjects was 65.3 +/- 2.5 pg/ml. Paroxysmal tachycardia and rapid atrial pacing significantly increased IR-ANF in human plasma. Two- to seven-fold higher concentrations were found in coronary sinus blood than in the peripheral circulation. In the plasma of rats and humans, circulating ANF is probably a small-molecular-weight peptide. ANF acts on the adrenal and the pituitary. ANF inhibits aldosterone secretion from rat zona glomerulosa and steroid secretion by bovine adrenal zona glomerulosa and fasciculata. ANF stimulated the basal secretion of arginine vasopressin (AVP) in vitro and inhibited KCl-stimulated release of AVP.

  7. Transient downregulation of glomerular atrial natriuretic factor receptors in high output heart failure in the rat.

    Science.gov (United States)

    Gauquelin, G; Bonhomme, M C; Garcia, R

    1995-03-01

    The renal response to exogenous atrial natriuretic factor (ANF) is blunted in chronic heart failure. The aim of the present studies was to investigate whether renal ANF receptor regulation in chronic heart failure is a time related event. Glomerular ANF receptors were analysed in radioligand binding experiments at 0, 1, 2, 6, 12, 24, and 48 h, as well as at 1, 2, 4, and 8 weeks after the induction of an aortocaval shunt. Rats with aortocaval shunts had lower packed cell volume and body weight and higher relative heart weight than sham operated controls. Plasma ANF C and N terminal levels were increased in shunt rats as early as 5 min after establishment of the shunt. Right and left atrial ANF concentrations were decreased and ventricular ANF concentration was increased in shunt rats at 6 and 12 h respectively. Competitive inhibition of 125I-ANF binding showed that at 6 h the density (Bmax) of glomerular ANF receptors was significantly lower than in the controls [518(SEM 10) v 759(12) fmol.mg-1 protein] without differences in their affinity (Kd). The low Bmax in shunt animals persisted at 12, 24, and 48 h, even at 1 week [Bmax: 400(29) and 713(28) fmol.mg-1 protein; Kd: 80(2) and 70(4) pM, for AC rats and controls, respectively]. Bmax values were not significantly different at 2, 4, and 8 weeks. In 24 h animals, C-ANF displaced 65% of total binding, with both total and C ANF binding sites being 38% lower in shunt animals. Downregulation of glomerular ANF receptors is a transient event during the development of high output heart failure in the rat. Thus the blunted renal response to ANF during chronic heart failure is not likely to be due to a decrease in renal ANF receptor density or affinity.

  8. In vitro interactions between anidulafungin and nonsteroidal anti-inflammatory drugs on biofilms of Candida spp.

    Science.gov (United States)

    Rosato, Antonio; Catalano, Alessia; Carocci, Alessia; Carrieri, Antonio; Carone, Addolorata; Caggiano, Giuseppina; Franchini, Carlo; Corbo, Filomena; Montagna, Maria Teresa

    2016-03-01

    Candida spp. are responsible for many biomaterial-related infections; they give rise to infective pathologies typically associated with biofilm formation. We recently reported that the echinocandin anidulafungin (ANF) showed a strong in vitro activity against both planktonic and biofilms cells. Herein, we report the antifungal activities of ANF alone and in association with some non-steroidal anti-inflammatory drugs (NSAIDs) against nine Candida strain biofilms: four Candida albicans, two Candida glabrata and three Candida guilliermondii. The activity of ANF was assessed using an in vitro microbiological model relevant for clinical practice. ANF proved oneself to be active against biofilms cells, and a clear-cut synergism was found against Candida species biofilms when ANF was used in combination with three NSAIDs: aspirin, diclofenac, ibuprofen. The positive synergism against Candida spp. of ANF in association with aspirin or the other NSAIDs proved to be a very effective antifungal treatment (FICICandida biofilm pathologies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Ablation Performances of the HfC Modified Carbon/carbon Composite Integrated Throat%HfC改性C/C复合材料整体喉衬的烧蚀性能研究

    Institute of Scientific and Technical Information of China (English)

    李淑萍; 李克智; 郭领军; 和永岗

    2008-01-01

    采用热梯度化学气相沉积工艺制备了碳化铪改性和未改性整体炭毡增强的炭/炭(C/C)复合材料整体喉衬,采用小型固体火箭发动机试车台装置(平均工作压强为7MPa)测定了它们的烧蚀性能.结合扫描电镜(SEM)和能谱(EDS)分析,讨论了碳化铪改性对C/C复合材料整体喉衬烧蚀行为的影响.结果表明,与未改性的C/C复合材料整体喉衬相比,碳化铪改性C/C复合材料整体喉衬的烧蚀过程中存在一个线烧蚀率恒定的稳定烧蚀阶段,且其线烧蚀率减小了34%,质量烧蚀率减小了13%.

  10. Random survey of HFC and R22 emission, refrigerants and leakage percentage in the dairy, meat and other food industries; Steekproefonderzoek HFK en R22-emissies, koudemiddelvulling en lekpercentage in de Zuivel, Vlees en Overige voedingsmiddelensectoren

    Energy Technology Data Exchange (ETDEWEB)

    Pennartz, A.M.G.; Van den Bovenkamp, M.V. [KWA Bedrijfsadviseurs, Amersfoort (Netherlands)

    2012-08-15

    The EU member states are obliged to bring the EU F-gas and Ozone policy into operation, by minimalizing the R22 and F-gas emissions in cooperation with market parties. Factors that may guide the refrigerant emission policy are: leakage percentages per year (company level, sector, national level); emission quantities (company level, sector, national level); indirect indicators: knowledge, experience with refrigerating contractors, feed back to end users, proactive prevention by end users. At this moment there is no clear view of the emission percentages in practice with the end users. For this reason the Dutch Ministry of Infrastructure and the Environment, by NL Agency, has initiated a random test survey in the Dairy, Meat and Other Food sectors. The main goal is to obtain data on the size and trends of R22 and HFK emissions in the period 2007-2010 [Dutch] De EU-lidstaten dienen uitvoering te geven aan het EU F-gas en Ozon-beleid, door met de markt te streven naar minimale R22 en F-gas emissies bij de eindgebruikers. Indicatoren (trends) om het koudemiddel emissiebeleid op te kunnen sturen zijn: jaarlijks optredende lekpercentages (per bedrijf, sector, totaal NL); emissiehoeveelheden (per bedrijf, sector, totaal NL); indirecte factoren: kennis/ervaring in lekkagepreventie bij koelinstallateurs, terugkoppeling naar de opdrachtgevers, preventiebeleid/prioriteit vanuit de opdrachtgevers. Tot nu toe ontbreekt een scherp beeld van de optredende lekpercentages (grootte, trends) bij de eindverbruikers. Daarom is door het Ministerie van IenM, via Agentschap NL een steekproefonderzoek uitgezet in de sectoren Zuivel, Vlees en Overige voedingsmiddelen. Doel is een beeld te krijgen van de omvang en trend van de R22 en HFK-emissies over 2007-2010.

  11. Ozone depleting substances and gases HFCs, PFCs and SF{sub 6}. Consumption and emissions 2003; Ozonlagsnedbrydende stoffer og drivhusgasserne HFC'er PFC'er og SF6. Forbrug og emissioner 2003

    Energy Technology Data Exchange (ETDEWEB)

    Sander Poulsen, T.

    2005-07-01

    The evaluation includes a calculation of actual emissions of HFCs, PFCs and SF{sub 6} in Denmark. In this calculation of actual emissions, the release from stock of greenhouse gases in products has been taken into account, and adjustments have been made for imports and exports of the greenhouse gases in products. The evaluation has partly been prepared to enable Denmark to fulfil its international obligations to provide information within this area, and partly to follow the trend in consumption and emissions of HFCs, PFCs and SF{sub 6}. (BA)

  12. Ozone depleting substances and greenhouse gases HFCs, PFCs and SF{sub 6} consumption and emissions; Ozonlagsnedbrydende stoffer og drivhusgasserne HFC'er, PFC'er og SF{sub 6}. Forbrug og emissioner 2002

    Energy Technology Data Exchange (ETDEWEB)

    Sander Poulsen, T. [Planmiljoe, Veksoe Sjaelland (Denmark)

    2004-07-01

    The aim of the project is to map the 2002 Danish consumption of produced ozone depleting substances and the consumption and actual emission of the greenhouse gases HFCs, PFCs and SF{sub 6}. The inventory is performed, partly according to the guidelines recommended by IPCC (Intergovernmental Panel on Climate Change), and partly according to the method that has been used for previous mappings. The mapping is done partly in order to meet Denmark's international commitments to report and partly in order to monitor how the consumption of ozone depleting substances and the emissions of greenhouse gases develop. The mapping of ozone depleting substances includes the net consumption, meaning the amount of the imported raw materials in bulk or in drums minus any re-export of the substances in the form of raw materials. Mapping of the actual emissions of HFCs, PFCs and SF{sub 6} is done in continuation of previous greenhouse gas inventories. The inventory process is continuously improving due to development of international approved guidelines (IPCC) and the production of increasingly detailed data. (BA)

  13. Interconnection Schemes of VoIP Service and Existing Common Network via HFC Network%HFC网络开展VoIP业务与现有公用网络互联的方案

    Institute of Scientific and Technical Information of China (English)

    王坚

    2005-01-01

    利用HFC网络开展VoIP业务所面临的首要问题是如何与现有公用网络互联互通.为此介绍了三个参考方案:本地汇聚方案、CPN(Customer Premise Network,用户驻地网)+IP,CPN+PSTN(Public Switched Telephone Network,公共交换电话网)方案,并对其进行了分析比较,提出了解决方案.

  14. The role of neutral endopeptidase in dogs with evolving congestive heart failure.

    Science.gov (United States)

    Margulies, K B; Barclay, P L; Burnett, J C

    1995-04-01

    Recent studies suggest that neurohumoral mechanisms including decreased renal responses to increases in atrial natriuretic factor (ANF) play a central role in the progression from asymptomatic cardiac dysfunction to advanced congestive heart failure (CHF) with sodium retention, vasoconstriction, and reduced exercise tolerance. Recognizing that neutral endopeptidase 24.11 degrades ANF and may be enhanced in CHF, we hypothesized that chronic neutral endopeptidase inhibition (NEP-I) would potentiate renal responses to exogenous ANF and alter the temporal evolution of sodium retention in evolving CHF by potentiation of increased endogenous ANF. We studied 13 conscious dogs with evolving CHF produced by rapid ventricular pacing at 250 beats per minute. Six of these dogs received NEP-I with candoxatril, 10 mg/kg PO BID, throughout evolving CHF. Responses to exogenous ANF, 10 micrograms/kg IV bolus, were assessed at baseline and after 6 days of CHF. Daily metabolic studies during evolving CHF with chronic NEP-I showed increased sodium excretion and renal cGMP generation consistent with enhanced renal activity of endogenous ANF compared with untreated controls. In addition, renal natriuretic and cGMP responses to exogenous ANF were intact in CHF with chronic NEP-I in contrast to markedly attenuated renal responses to exogenous ANF in untreated CHF. Despite enhanced ANF responsiveness and improved sodium balance in evolving CHF, a moderate degree of sodium retention was observed during chronic NEP-I in evolving CHF. Enzymatic degradation by neutral endopeptidase limits local renal responses to increases in endogenous and exogenous ANF in CHF independent of changes in systemic hemodynamics or augmented plasma concentrations of ANF. The moderate sodium retention observed during evolving CHF despite chronic NEP-I probably reflects the antinatriuretic effects of hemodynamic and humoral factors independent of ANF activity.

  15. Energetics of Heterotropic Cooperativity between α-Naphthoflavone and Testosterone Binding to CYP3A4

    Science.gov (United States)

    Roberts, Arthur G.; Atkins, William M.

    2007-01-01

    Cytochrome P450 3A4 (CYP3A4) is involved in the metabolism of a majority of drugs. Heterotropic cooperativity of drug binding to CYP3A4 was examined with the flavanoid, α-naphthoflavone (ANF) and the steroid, testosterone (TST). UV-vis and EPR spectroscopy of CYP3A4 show that ANF binding to CYP3A4 occurs with apparent negative cooperativity and that there are at least two binding sites: 1) a relatively tight spin-state insensitive binding site (CYP●ANF) and 2) a relatively low affinity spin-state sensitive binding site (CYP●ANF●ANF). Since binding to the spin-state insensitive binding site is considerably tighter for ANF than TST, the spin-state insensitive binding site could be occupied by ANF, while titrating TST at the other site(s). The spin-state insensitive binding site of ANF appears to compete with the spin-state insensitive binding site of TST. The formation of the spin-state insensitive CYP●ANF complex is strongly temperature dependent, when compared to the formation of the CYP●TST complex, suggesting that the formation of the CYP3A4●ANF complex leads to long-range conformational changes within the protein. When the CYP●ANF complex is titrated with TST, the formation of CYP●ANF●TST is favored by 3:1 over the formation of CYP●TST●TST, suggesting that there is an allosteric interaction between ANF and TST. A model of heterotropic cooperativity of CYP3A4 is presented, where the spin-state insensitive binding of ANF occurs at the same peripheral binding site of CYP3A4 as TST. PMID:17459328

  16. The Role of Natriuretic Agents In the Mechanism of Hypertension in the Dahl Strain of Salt-Sensitive and Salt-Resistant Rats

    Science.gov (United States)

    1986-07-02

    Roger and Virginia, and to Dina, a very special friend and companion. vi ACKNOWLEDGEMENTS A special and sincere thank you goes to Dr. Pamnani...the atrial extracts, suggesting that ANF was involved. Chartier et al. (1984) examined the actions of natural ANF 8-33, ANF 1-73 and synthetic...polypeptide in the heart and plasma of rats and human., Fed. Proc. 44(3): 1241, 1985. Chartier , L., Schiffrin, E. and Thibault, G.: Effect of atrial

  17. Splanchnic removal of human alpha-atrial natriuretic peptide in humans: enhancement after food intake

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik; Bendtsen, Flemming; Gerbes, A L

    1990-01-01

    In order to assess the effect of food ingestion on splanchnic disposal of human alpha-atrial natriuretic peptide (ANF), hepatic-intestinal removal of ANF was determined before and after a test meal. Hepatic venous and arterial plasma samples were obtained from six subjects, most of whom had only...... disorders of minor degree. Hepatic blood flow (HBF) increased significantly after meal ingestion (1.10 +/- 0.17 [SEM] to 1.51 +/- 0.26 L/min, P less than .01). Baseline arterial ANF (10.9 +/- 3.1 pmol/L) did not change significantly. In contrast, hepatic venous ANF increased after meal intake (5.7 +/- 2...

  18. Splanchnic removal of human alpha-atrial natriuretic peptide in humans: enhancement after food intake

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Bendtsen, F; Gerbes, A L

    1990-01-01

    In order to assess the effect of food ingestion on splanchnic disposal of human alpha-atrial natriuretic peptide (ANF), hepatic-intestinal removal of ANF was determined before and after a test meal. Hepatic venous and arterial plasma samples were obtained from six subjects, most of whom had only...... .05). Splanchnic removal of ANF was 3.0 +/- 0.5 pmol/min before and increased to a maximum value (7.1 +/- 2.2 pmol/min, P less than .05) 35 minutes after ingestion of the meal. Our results showed enhanced splanchnic removal of ANF after food intake. This is due to increased hepatic...

  19. SUBSTITUCIÓN ASIMÉTRICA ENTRE METANFETAMINA Y ANFETAMINA: ESTUDIO DE DISCRIMINACIÓN DE DROGAS

    OpenAIRE

    Florencio Miranda; Benita Cedillo-Ildefonso; Juan C. Jiménez; Gloria Bedolla-Núñez; Sandra Torres-Rodríguez

    2011-01-01

    La metanfetamina (MET) es una forma estructural y funcionalmente similar a la anfetamina (ANF). Sin embargo, la MET difiere de la ANF en que a dosis comparables, entran al cerebro niveles más altos de MET, haciéndola un psicoestimulante más potente que la ANF. A pesar de esto, se ha reportado que tanto la MET como la ANF producen efectos conductuales similares. Los procedimientos de discriminación de drogas son herramientas conductuales que se utilizan para evaluar si dos drogas producen efec...

  20. Mutationsanalyse im SCN1A-Gen bei frühkindlichen myoklonischen Epilepsien unter besonderer Betrachtung der myoklonisch-astatischen Epilepsie und der frühkindlichen Epilepsie mit generalisierten tonisch-klonischen Anfällen und alternierendem Hemi-Grand mal

    OpenAIRE

    2005-01-01

    Die myoklonisch-astatische Epilepsie, die schwere myoklonische Epilepsie des Kindesalters und die frühkindliche Grand mal-Epilepsie mit alternierendem Hemi-Grand mal gehören zu den frühkindlichen myoklonischen Epilepsien. Alle drei Syndrome sind genetisch determinierte idiopathische generalisierte Epilepsien. In Großfamilien mit gehäuft auftretenden generalisierten Epilepsien (sog. GEFS+-Syndrom) wurden ursächliche Mutationen in Genen von vier Ionenkanälen (SCN1A, SCN1B, SCN2A, GABRG2) na...

  1. 艾灸对运动训练大鼠血乳酸、心钠素、皮质醇及脏器指数水平影响的实验研究%Experiment study on training rat blood lactic acid, ANF, cortisol and internal organs index level influenced by Moxa

    Institute of Scientific and Technical Information of China (English)

    顾长海

    2007-01-01

    艾灸在改善心肺功能、提高免疫系统水平、增强机体物质储备方面有着独特功效.为探讨艾灸对运动训练大鼠皮质醇、心钠素、血乳酸水平及脏器指数的影响,以SD雄性大鼠为实验对象,建立跑台运动训练模型.将实验大鼠随机分组为安静对照组、训练对照组、艾灸训练组,每组各8只.测定皮质醇、心钠素、血乳酸及脏器指数水平等指标.研究结果显示,长期大强度训练引起大鼠体重显著性下降,艾灸可以抑制这一下降趋势;大强度训练可以引起血乳酸含量升高,艾灸加快了运动过程中血乳酸的清除速率;长期大强度训练引起大鼠心钠素水平显著性下降,艾灸可以抑制这一下降趋势;有效抑制了运动造成皮质醇水平的升高;抑制这种由于大强度耐力性项目造成的脏器指数变化.提示,艾灸可望作为现代高水平运动队常用的一种培补手段.

  2. Removal of atrial natriuretic factor by perfused rabbit lungs in situ

    Energy Technology Data Exchange (ETDEWEB)

    Turrin, M.; Maack, T.; Gillis, C.N.

    1986-03-05

    Because atrial natriuretic factor (ANF) can be released from the right atrium into pulmonary blood, the authors studied the possibility of uptake of the peptide by rabbit lung, perfused in situ, at 20 ml/min with Krebs-albumin medium. Single pass removal (multiple indicator dilution with /sup 14/C-dextran as reference) of trace amounts (40 pmoles) of /sup 125/I-ANF was 66 +/- 4% (n=12). This was reduced to 8 +/- 4% by co-injection of 10 ..mu..M ANF but was unchanged by co-injection of CPAP (340 nM), an inhibitor of angiotensin-converting enzyme (ACE). When /sup 125/I-ANF was re-circulated through lung, uptake reached maximum at 14 min (64 +/- 5%; n=7). Efflux of /sup 125/I-ANF from preloaded lungs was monoexponential with t/sub 1/2/ = 17.7 min. Recovery of /sup 125/I-ANF uptake after block by unlabelled ANF was studied. For this purpose, lungs were loaded with 0.1 ..mu..M unlabelled ANF by recirculating for 20 minutes, after which medium was changed to Krebs-albumin and removal of bolus injections of /sup 125/I-ANF was measured every 5 min. Removal of /sup 125/I-ANF, initially 0%, returned to control levels after 20 min. Thus, /sup 125/I-ANF is removed from the pulmonary circulation by a saturable and reversible process which probably does not involve binding to the ACE present on endothelial cells.

  3. Vapor Pressure of Pentafluoroethane and Trifluoroiodomethane

    Institute of Scientific and Technical Information of China (English)

    Zhang Chang; Duan Yuanyuan; Shi Lin; Zhu Mingshan; Han Lizhong

    2001-01-01

    Pentafluoroethane (HFC-125) and trifluoroiodomethane (CF3I) are considered as promising refrigerant alternatives, especially as components in mixtures, to replace CFCs or HCFCs. Effective uses of HFC-125 and CF3I require that the thermophysical properties be accurately measured. In the present work, vapor pressure data of HFC-125 and CF3I have been measured in the temperature range from 292 to 337 K and 288 to 336 K,respectively. Maximum total pressure uncertainty of HFC-125 data is estimated to be within ±1.2 kPa and ±780 Pa for CF3I. Based on the data set and literature values, the vapor pressure equations for HFC-125 and CF3I have been developed. The relative deviation of the equations correlate the measurements within 0.022% for HFC-125 and 0.068% for CF3I, respectively.

  4. Hafnium carbide structural foams synthesized from polymer precursors

    Institute of Scientific and Technical Information of China (English)

    FAN Hai-bo; YANG Hong; N. K. RAVALA; H. C. WIKLE III; R. H. ZEE; B. A. CHIN

    2006-01-01

    Hafnium carbide (HfC) was applied in space and aerospace due to its ultra high melting temperature, high specific strength and moderate oxidation resistance. A novel synthesizing method was used to produce low density and high strength HfC structural foams through the thermolysis and pyrolysis of Hf containing polymer precursors (mixing of hafnium trifluoroacetylacetonate and epoxy) under vacuum atmosphere. The X-ray diffraction analysis shows that the produced foam is primarily composed of HfC containing 9%-10% HfO2. Several polymer powder compaction methods were used to improve the mechanical properties of HfC foam. Compression strengths of 200 MPa are achieved for HfC foams with density of 1.9 g/cm3 (total porosity about 85%). The proposed methodology of synthesizing HfC foam has the advantages of simple, inexpensive and less production time than alternate methods.

  5. 应用于空调和热泵中的R407C和R410A制冷剂的参数与性能

    Institute of Scientific and Technical Information of China (English)

    耿永辉

    2005-01-01

    R404C是一种三元混合的含氢氟烃物质,它由BFC-32,HFC125,BFC-134a按23/25/52wt%比例混合。R410A是一种二元混合型制冷剂,由HFC-32,HFC-125按50/50wt%的比例混合。

  6. White ash (Fraxinus americana) health in the Allegheny plateau region, Pennsylvania: Evaluating the relationship between FIA phase 3 crown variables and a categorical rating system

    Science.gov (United States)

    Alejandro A. Royo; Kathleen S. Knight; Jamie M. Himes; Ashley N. Will

    2012-01-01

    Following the detection of white ash (Fraxinus americana) decline in the Allegheny National Forest (ANF) of Pennsylvania, we established an intensified white ash monitoring network throughout the ANF. We rated crowns using both a categorical system as well as Forest Inventory and Analyses (FIA) Phase 3 measures of uncompacted live crown ratio,...

  7. Receptor binding sites for atrial natriuretic factor are expressed by brown adipose tissue

    Energy Technology Data Exchange (ETDEWEB)

    Bacay, A.C.; Mantyh, C.R.; Vigna, S.R.; Mantyh, P.W. (Wadsworth VA Medical Center, Los Angeles, CA (USA))

    1988-09-01

    To explore the possibility that atrial natriuretic factor (ANF) is involved in thermoregulation we used quantitative receptor autoradiography and homogenate receptor binding assays to identify ANF bindings sites in neonatal rat and sheep brown adipose tissue, respectively. Using quantitative receptor autoradiography were were able to localize high levels of specific binding sites for {sup 125}I-rat ANF in neonatal rat brown adipose tissue. Homogenate binding assays on sheep brown fat demonstrated that the radioligand was binding to the membrane fraction and that the specific binding was not due to a lipophilic interaction between {sup 125}I-rat ANF and brown fat. Specific binding of {sup 125}I-rat ANF to the membranes of brown fat cells was inhibited by unlabeled rat ANF with a Ki of 8.0 x 10(-9) M, but not by unrelated peptides. These studies demonstrate that brown fat cells express high levels of ANF receptor binding sites in neonatal rat and sheep and suggest that ANF may play a role in thermoregulation.

  8. A Model of Electrically Stimulated Auditory Nerve Fiber Responses with Peripheral and Central Sites of Spike Generation

    DEFF Research Database (Denmark)

    Joshi, Suyash Narendra; Dau, Torsten; Epp, Bastian

    2017-01-01

    A computational model of cat auditory nerve fiber (ANF) responses to electrical stimulation is presented. The model assumes that (1) there exist at least two sites of spike generation along the ANF and (2) both an anodic (positive) and a cathodic (negative) charge in isolation can evoke a spike. ...

  9. Regularized Adaptive Notch Filters for Acoustic Howling Suppression

    DEFF Research Database (Denmark)

    Gil-Cacho, Pepe; van Waterschoot, Toon; Moonen, Marc;

    2009-01-01

    In this paper, a method for the suppression of acoustic howling is developed, based on adaptive notch filters (ANF) with regularization (RANF). The method features three RANFs working in parallel to achieve frequency tracking, howling detection and suppression. The ANF-based approach to howling...

  10. HFO1234ze(E) Boiling Inside a Brazed Plate Heat Exchanger

    OpenAIRE

    Longo, Giovanni A.; Mancin, Simone; Righetti, Giulia; Zilio, Claudio

    2016-01-01

    HFC134a has been probably the most important refrigerant of the two past decades as it dominated the application in domestic refrigeration, mobile air conditioning and large chillers and it took part as component in several refrigerant mixtures such as HFC404A, and HFC407C. Unfortunately HFC134a exhibits a relatively large Global Warming Potential (GWP), and it will be subjected to a gradual reduce in the use up to a complete phase out in the next future according to the different national an...

  11. Dehydration-induced changes in the secretion of atrial natriuretic factor in Brattleboro rats: effect of water-drinking.

    Science.gov (United States)

    Januszewicz, P; Gutkowska, J; Thibault, G; Garcia, R; Mercure, C; Jolicoeur, F; Genest, J; Cantin, M

    1986-06-18

    The secretion of atrial natriuretic factor (ANF) was measured in Brattleboro rats (DI) subjected to 20-h dehydration and in normal Long-Evans rats (LE) subjected to 72-h dehydration and 7 times within the hour following voluntary rehydration by drinking water. In these rats, water deprivation caused a large, significant drop in plasma immunoreactive ANF (IR-ANF). Drinking water did not restore plasma IR-ANF values within one hour, even when indirect indices of intravascular volume such as serum osmolality, sodium and hematocrit returned to normal. The dehydration-induced decrease in plasma IR-ANF and its very low secretion after restoring drinking may be essential for the homeostasis of water conservation in both DI and LE rats.

  12. Atrial natriuretic factor inhibits mitogen-induced growth in aortic smooth muscle cells.

    Science.gov (United States)

    Baldini, P M; De Vito, P; Fraziano, M; Mattioli, P; Luly, P; Di Nardo, P

    2002-10-01

    Atrial natriuretic factor (ANF) is a polypeptide able to affect cardiovascular homeostasis exhibiting diuretic, natriuretic, and vasorelaxant activities. ANF shows antimitogenic effects in different cell types acting through R(2) receptor. Excessive proliferation of smooth muscle cells is a common phenomenon in diseases such as atherosclerosis, but the role of growth factors in the mechanism which modulate this process has yet to be clarified. The potential antimitogenic role of ANF on the cell growth induced by growth factors appears very intriguing. Aim of the present study was to investigate the possible involvement of ANF on rat aortic smooth muscle (RASM) cells proliferation induced by known mitogens and the mechanism involved. Our data show that ANF, at physiological concentration range, inhibits RASM cell proliferation induced by known mitogens such as PDGF and insulin, and the effect seems to be elicited through the modulation of phosphatidic acid (PA) production and MAP kinases involvement.

  13. Expression of biologically active atrial natriuretic factor following intrahepatic injection of a replication-defective adenoviral vector in dogs.

    Science.gov (United States)

    Chetboul, V; Adam, M; Deprez, I; Ambriovic, A; Rosenberg, D; Crespeau, F; Saana, M; Pham, I; Eloit, M; Adnot, S; Pouchelon, J L

    1999-01-20

    Atrial natriuretic factor (ANF) is a potent natriuretic, diuretic, and vasoactive hormone produced and released by atrial cardiomyocytes. We investigated whether adenovirus-mediated ANF gene delivery to dogs leads to a sustained increase in circulating ANF levels resulting in long-lasting biological effects. An adenoviral vector containing the canine ANF cDNA under the control of the Rous sarcoma virus 3' long terminal repeat (AdRSV-ANF) was injected via the intrahepatic route to nonvaccinated 2-month-old dogs. In the first group of four dogs injected with AdRSV-ANF (10(10.2) TCID50), a short-lived increase in plasma ANF concentrations not associated with biological effects occurred 8-10 days after the injection, as compared with four control dogs injected with an adenovirus encoding a luciferase reporter gene (AdRSV-luc). In a second series of experiments, six dogs received AdRSV-ANF at a dose of 10(10) TCID50 and a replication-defective type 5 adenovirus harboring a modified VAI gene (Ad-VAr) at the same dose. Sustained increases in plasma ANF concentrations and urinary cGMP excretion starting on day 2 and persisting until day 20 were seen, as well as concomitant elevations in natriuresis and diuresis, a transient increase in cardiac output, and a delay in body weight gain, as compared with control dogs injected with AdRSV-luc/Ad-VAr. These results show that adenovirus-mediated ANF gene expression can lead to systemic biological effects in dogs, a finding of potential relevance for the treatment of cardiovascular diseases and sodium-retaining disorders.

  14. Extra-atrial expression of the gene for atrial natriuretic factor.

    Science.gov (United States)

    Gardner, D G; Deschepper, C F; Ganong, W F; Hane, S; Fiddes, J; Baxter, J D; Lewicki, J

    1986-01-01

    Atrial natriuretic factor (ANF) is a group of peptides, originally isolated from the cardiac atria, that have a number of important effects on blood pressure, renal function, and salt balance. In the current study, expression of the ANF gene in certain extra-atrial tissues of the rat has been examined by radioimmunoassay of extracted ANF protein and by blot-hybridization, nuclease S1 analysis, and primer-extension analysis of the ANF mRNA. ANF peptides and mRNA were detected in cardiac ventricles, lung, and pituitary gland at levels generally less than or equal to 1% those of cardiac atria. The ANF transcripts in extra-atrial tissue appear to be very similar to those synthesized in the atria. They are polyadenylylated, are equivalent in overall length (950-1050 nucleotides), and have identical 5' termini. A secondary transcription start site mapping approximately 80 base pairs upstream from the primary start site is employed in atria and to a lesser extent in other tissues. The ANF transcript is present throughout the cardiac ventricles from apex to base and in the septum as well as the ventricular free walls. The transcript is more prevalent in the left ventricle and interventricular septum than in the right ventricle. Immunocytochemistry using various anti-rat ANF antibodies localized ANF immunoreactivity to the atrial myocytes; the ventricular myocytes, particularly along the endothelial surface of the ventricular chamber; perialveolar cells in the lung; and the gonadotropin-producing cells of the pituitary. The data indicate that the capacity for ANF gene expression extends beyond atrial tissue, albeit at much reduced levels, and may suggest alternative, perhaps paraendocrine, functions for the peptide in these tissues. Images PMID:2428040

  15. Hafnium carbide structural foams synthesized from polymer precursors

    Science.gov (United States)

    Fan, Haibo

    2005-11-01

    A study was conducted to investigate a new low cost approach to produce Hafnium Carbide (HfC) structural foams through the thermolysis and pyrolysis of polymer precursors. Hafnium carbide has a melting point of over 3900 °C, the highest melting point of any known binary alloy. HfC structural foams can be fabricated into high temperature components or used as a thermal insulation material. Current available methods for creating HfC structural foams are time consuming, expensive or the material produced lacks mechanical strength. The objectives of this research were to produce HfC foam through the thermolysis and pyrolysis of Hf containing polymer mixture, optimize the properties of the HfC foam, and develop a knowledge base of acceptable process parameters. With the proposed method, HfC foam was produced by mixing a hafnium containing Macromolecular Metal Complex (MMC) and carbon source polymers, followed by heat treating the mixture under vacuum. XRD analysis showed that the produced foam was largely composed of HfC, with small amounts of hafnium oxide. The foam total porosity was measured to be over 85%. The HfC lattice parameter was found to range from 0.4613 nm to 0.4647 nm. The HfC conversion mechanism was investigated using Residual Gas Analysis, where it was observed that polymer decomposition occurred from 80 through 550 °C and HfC conversion started around 1100 °C. The HfC foam mechanical properties and microstructure were improved by optimizing the process methods and parameters. The initial research yielded an HfC foam with a compression strength of 15.16 +/- 4.66 MPa and evenly distributed foam cells with diameter sizes up to 50 mum. Continued research showed that HfC foams with total porosity of about 85% (density 1.9g/cm 3), and a foam compression strength of 212 +/- 25MPa were achievable. The proposed methodology for synthesizing HfC foam was found to be simple, inexpensive and require less production time. The process can be controlled to produce

  16. 40 CFR 98.157 - Records that must be retained.

    Science.gov (United States)

    2010-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING HCFC-22 Production and HFC-23 Destruction § 98.157 Records... shall retain the following records: (1) The data used to estimate HFC-23 emissions. (2) Records documenting the initial and periodic calibration of the gas chromatographs, weigh scales, volumetric...

  17. 78 FR 29034 - Protection of Stratospheric Ozone: Determination 28 for Significant New Alternatives Policy Program

    Science.gov (United States)

    2013-05-17

    ... of Acceptability. SUMMARY: This Determination of Acceptability expands the list of acceptable... substitutes in: Rigid polyurethane spray Extruded polystyrene, boardstock and billet HFC-365mfc is also known.... Extruded polystyrene, boardstock Commercial blends of HFC- Acceptable The manufacturer has an and...

  18. Analysis of South Carolina hydrogen and fuel cell workers views and opinion leadership behavior: A waiting opportunity?

    Energy Technology Data Exchange (ETDEWEB)

    Besley, John C. [School of Journalism and Mass Communications, University of South Carolina, Columbia, SC 29205 (United States); Baxter-Clemmons, Shannon [South Carolina Hydrogen Fuel Cell Alliance, P.O. Box 12302, Columbia, SC 29201 (United States)

    2010-08-15

    The current study uses quantitative survey results to explore what a near census of hydrogen and fuel cell (HFC) workers in South Carolina (n = 70) say about their HFC experiences and the degree to which these workers can be expected to act as opinion leaders for the field. In general, these workers say they are positive about the environmental, national security, and economic potential of HFC technologies. They further see HFC technologies as having small and manageable levels of risk. A number of these workers exhibit characteristics associated with both issue-specific and general opinion leadership. Issue-specific leadership and positive views about HFC technology were associated with higher levels of self-reported technology-related interpersonal discussion. The study concludes that the existence of workers with positive HFC experiences and a demonstrated interest in telling others about their experiences may represent an opportunity for those charged with promoting HFC development and adoption. Future efforts should explore how HFC workers could be effectively integrated into such efforts as a means of reaching difficult to reach audiences. (author)

  19. Alternatives to HCFC-22 for air conditioners

    Energy Technology Data Exchange (ETDEWEB)

    Devotta, S. [Council of Scientific and Industrial Research, National Chemical Lab., Pune (India); Waghmare, A.V.; Domkundwar, B.M. [College of Engineering, Pune (India); Sawant, N.N. [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

    2001-04-01

    Some selected fluids have been assessed for their suitability as alternatives to HCFC-22 for air conditioners. Only those refrigerants with zero ozone depletion potential are considered. NIST CYCLE{sub D} has been used for the comparative thermodynamic analysis. Among the refrigerants studied (HFC-134a, HC-290, R-407C, R-410A, and three blends of HFC-32, HFC-134a and HFC-125), HFC-134a offers the highest COP, but its capacity is the lowest and requires much larger compressors. The characteristics of HC-290 are very close to those of HCFC-22, and compressors require very little modification. Therefore, HC-290 is a potential candidate provided the risk concerns are mitigated as had been accomplished for refrigerators. For retrofitting, R-407C is probably the best candidate. (Author)

  20. Cryoinsulation Material Development to Mitigate Obsolescence Risk for Global Warming Potential Foams

    Science.gov (United States)

    Protz, Alison; Bruyns, Roland; Nettles, Mindy

    2015-01-01

    Cryoinsulation foams currently being qualified for the Space Launch System (SLS) core stage are nonozone- depleting substances (ODP) and are compliant with current environmental regulations. However, these materials contain the blowing agent HFC-245fa, a hydrofluorocarbon (HFC), which is a Global Warming Potential (GWP) substance. In August 2014, the Environmental Protection Agency (EPA) proposed a policy change to reduce or eliminate certain HFCs, including HFC-245fa, in end-use categories including foam blowing agents beginning in 2017. The policy proposes a limited exception to allow continued use of HFC and HFC-blend foam blowing agents for military or space- and aeronautics-related applications, including rigid polyurethane spray foams, but only until 2022.

  1. Die Rolle der P II -Proteine GlnB und GlnK bei der Regulation des Stickstoff-Metabolismus in dem phototrophen Purpurbakterium Rhodobacter capsulatus

    OpenAIRE

    2002-01-01

    Das phototrophe Purpurbakterium Rhodobacter capsulatus ist in der Lage über eine Molybdän-Nitrogenase (nif-codiert) oder eine alternative Heterometall-freie Nitrogenase (anf-codiert) atmosphärischen Stickstoff zu fixieren. Die Expression und die Aktivität beider Nitrogenase-Systeme wird über die Stickstoffverfügbarkeit auf drei Ebenen reguliert. 1. die Regulation der Transkription der nif- und anf-spezifischen Transkriptionsaktivatoren NifA1, NifA2 und AnfA. 2. die Regulation i...

  2. The interaction of cadmium with atrial natriuretic factor: A study in in vivo and in vitro models

    Energy Technology Data Exchange (ETDEWEB)

    Giridhar, J.

    1990-01-01

    The involvement of atrial natriuretic factor (ANF) and its receptor in cadmium(Cd)-induced cardiovascular alterations and neurotoxicity is not known. This study examines the mechanisms underlying Cd-induced changes in the ANF peptide and its receptor in cardiovascular toxicity. In rats on short term Cd exposure (0.01, 0.1, 0.5 and 1.0 mg/kg, i.p., twice a day for 7 days and a maintenance period of 30 days), atrial ANF levels decreased significantly in the Cd 1 mg/kg group; plasma ANF levels were unchanged. Hypothalamic ANF content decreased significantly in 0.1-1.0 mg/kg Cd groups. Plasma renin activity and concentration were unchanged by Cd treatment. However, plasma aldosterone was significantly decreased in Cd 1.0 mg/kg group. Binding of [sup 125]I-ANF to its receptors in kidney, adrenals and aorta was not significantly altered. Cd treatment decreased urine volume indicating nephrotoxicity. Neuromodulation by ANF involved significant decrease in K[sup +] stimulated [[sup 3]H]NE release in rat hypothalamic slices. This action is proposed to be mediated by ANF-B receptors. 8Br-cGMP mimicked this action. In Cd treated animals (0.5 mg/kg twice a day for 7 days and maintained for 30 days), ANF neuromodulation in the hypothalmus was blocked, even though Cd content was undetectable. Cd preincubated (0.5 mM) slices showed a 49.1% block in neurotransmitter release indicating that Cd may block calcium channels leading to decreased K[sup +]-stimulated release of [[sup 3]H]NE. Hence, Cd-induced cardiovascular toxicity and neurotoxicity may be partly mediated by alteration in the release and possibly the synthesis of ANF peptide, disruption of ANF function through alterations in receptor dynamics and possibly alteration in cellular calcium homeostasis and membrane integrity. Central ANF function is sensitive to Cd and this effect may be partly resposible for the cardiovascular and neurotoxic responses to CD.

  3. Measurement of viscosity, density, and gas solubility of refrigerant blends in selected synthetic lubricants. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Cavestri, R.C. [Imagination Resources, Inc., Dublin, OH (United States)

    1995-05-15

    The lubricants tested in this project were chosen based on the results of liquid/liquid miscibility tests. EMKARATE RL32S and Emery 2968A were selected. The Vapor Liquid Equilibrium (VLE) viscosity reduction and gas fractionation of each was measured with three different refrigerant blends: (1) R-404A; (2) R-507; and (3) R-407C. In addition, the four single refrigerants that make up the blends, HFC-32, HFC-125, HFC-134a, and HFC-143a, were also measured. Lubricants found to have the lowest liquid/liquid miscibilities had nearly equal viscosity reduction profiles as did the more miscible lubricants. Analytical methodology consisted of maintaining equally both the composition of the head space vapor above the lubricant/refrigerant mixture, and the composition of the liquid blend refrigerant. Blends with large temperature glides were re-evaluated in order to test the concept of head space quality and a vented piston hydraulic cylinder assembly was developed to perform this task. Fluid property data, above critical temperature and pressure conditions, is presented for the two lubricants with HFC-32, HFC-125, HFC-143a refrigerants. This research shows that the lubricant EMKARATE RL32S, which had the lowest (poorest) liquid/liquid miscibilities with the selected refrigerants, also had nearly equal viscosity reduction profiles to the more miscible Emery 2968A lubricant. The analytical methodology consisted of maintaining the composition of the refrigerant gas above the lubricant to be equal in composition to that of the pure liquid refrigerant blend being introduced into the lubricant. Refrigerant blends with large temperature glides were re-evaluated in order to validate the concept of the importance of the composition of the gas over the lubricant. To do perform this task, a special vented piston hydraulic cylinder assembly was developed. Fluid property data is also presented for HFC-32, HFC-125, and HFC-143a above the critical temperature and pressure of each.

  4. 75 FR 6762 - Self-Regulatory Organizations; Chicago Board Options Exchange, Incorporated; Notice of Filing and...

    Science.gov (United States)

    2010-02-10

    ... Program beginning on February 1, 2010: Symbol Company name Symbol Company name ABT Abbott Laboratories... Materials Inc. MCO Moody's Corp. AMR AMR Corp. MET MetLife Inc. ANF Abercrombie & Fitch Co. MMM 3M Co. APC...

  5. 75 FR 6756 - Self-Regulatory Organizations; NYSE Arca, Inc.; Notice of Filing and Immediate Effectiveness of...

    Science.gov (United States)

    2010-02-10

    ... Symbol Company name Nat'l ranking Symbol Company name 131 ABT Abbott 192 LEAP Leap Wireless Laboratories.... 166 ANF Abercrombie & 187 MMM 3M Co. Fitch Co. 172 APC Anadarko Petroleum 140 MU Micron Technology...

  6. The nifU, nifS and nifV gene products are required for activity of all three nitrogenases of Azotobacter vinelandii.

    Science.gov (United States)

    Kennedy, C; Dean, D

    1992-02-01

    Strains with mutations in 23 of the 30 genes and open reading frames in the major nif gene cluster of A. vinelandii were tested for ability to grow on N-free medium with molybdenum (Nif phenotype), with vanadium (Vnf phenotype), or with neither metal present (Anf phenotype). As reported previously, nifE, nifN, nifU, nifS and nifV mutants were Nif- (failed to grow on molybdenum) while nifM mutants were Nif-, Vnf- and Anf-. nifV, nifS, and nifU mutants were found to be unable to grow on medium with or without vanadium, i.e. were Vnf- Anf-. Therefore neither vnf nor anf analogoues of nifU, nifS, nifV or nifM are expected to be present in A. vinelandii.

  7. Experimental Study of Effect of Air Duct Structures on Heat Dissipation of Heating-Only Fan Coil

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-zhou; ZHAO Jia-ning

    2009-01-01

    Heating-only fan coil(HFC) is one of the suited end users.which is not only compact but also highly efficient.And the major factors affecting the heat dissipation performance of HFC include leakage through coil bypass,distance between fan and coil,fan structure and air inlet type.Under natural air convection or forced,experimental studies were made on the effects of these factors upon the heat dissipation performance of HFC.The results show that:1)After reducing the leakage through coil bypass,the heat dissipation of HFC in-creases 16.9%under natural convection,and increases 8.3%under forced convection.2)After the distance be-tween fan and coil be raised from 23.2cm to 41.7cm.the heat dissipation of HFC decreases 21.3%under natu-ral convection,but increasesl2.8%under forced convection.3)After changing the fan structure,the heat dissi-pation of HFC increases 41.8%under natural convection.and the heat dissipation per motor power increases 96.1%under forced convection.4)The heat dissipations of HFC with round pass,slit and strip type of air inlet are different,whose proportion is about 100%,110%,136%under natural convection,and 100%,105%,116%under forced convection.

  8. Oxidation Characterization of Hafnium-Based Ceramics Fabricated by Hot Pressing and Electric Field-Assisted Sintering

    Science.gov (United States)

    Gasch, Matt; Johnson, Sylvia; Marschall, Jochen

    2010-01-01

    Ceramic borides, such as hafnium diboride (HfB2) and zirconium diboride (ZrB2), are members of a family of materials with extremely high melting temperatures referred to as Ultra High Temperature Ceramics (UHTCs). UHTCs constitute a class of promising materials for use in high temperature applications, such as sharp leading edges on future-generation hypersonic flight vehicles, because of their high melting points. The controlled development of microstructure has become important to the processing of UHTCs, with the prospect of improving their mechanical and thermal properties. The improved oxidation resistance of HfB2 has also become important if this material is to be successfully used at temperatures above 2000 C. Furthermore, the use of UHTCs on the leading edges of vehicles traveling at hypersonic speeds will mean exposure to a mixed oxidation environment comprised of both molecular and atomic oxygen. The current study has investigated the high-temperature oxidation behavior of HfB2-based materials in a pure O2 environment, as well as in environments containing different levels of dissociated oxygen (O/O2). Materials were processed by two techniques: conventional hot pressing (HP) and electric field-assisted sintering (FAS). Their oxidation behavior was evaluated in both a tube furnace at 1250 C for 3 hours and in a simulated re-entry environment in the Advanced Heating Facility (AHF) arcjet at NASA Ames Research Center, during a 10-minute exposure to a cold wall heat flux of 250W/sq cm and stagnation pressure of 0.1-0.2 atm. The microstructure of the different materials was characterized before and after oxidation using scanning electron microscopy (SEM).

  9. Increased atrial natriuretic factor receptor density in cultured vascular smooth muscle cells of the spontaneously hypertensive rat

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, F.; Fine, B.; Kuriyama, S.; Hatori, N.; Nakamura, A.; Nakamura, M.; Aviv, A.

    1987-01-01

    To explore the role of the atrial natriuretic factor (ANF) system in the pathophysiology of hypertension we examined the binding kinetics of synthetic ANF to cultured vascular smooth muscle cells (VSMCs) derived from the spontaneously hypertensive rat (SHR) and two normotensive controls-the Wistar Kyoto (WKY) and American Wistar (W). The number of maximal binding sites (Bmax) per cell (mean +/- SEM; X10(3) were: SHR = 278.0 +/- 33.0, WKY = 28.3 +/- 7.1 and W = 26.6 +/- 4.2. The differences between the SHR and normotensive strains were significant at p less than 0.001. The equilibrium dissociation constant (Kd; X 10(-9)M) was higher in SHR VSMCs (0.94 +/- 0.14) than in WKY (0.22 +/- 0.09; p less than 0.01) and W (0.39 +/- 0.14; p less than 0.02) cells. The plasma levels of the immunoreactive ANF were higher in SHR than the normotensive controls. We suggest that the relatively greater ANF receptor density in cultured VSMCs of the SHR represents a response to the in vitro environment which is relatively more deficient in ANF for VSMCs of the SHR as compared with the normotensive rats. Thus, the capacity of the SHR VSMC to regulate ANF receptor density appears to be independent of the blood pressure level.

  10. High-Temperature Ceramic Matrix Composite with High Corrosion Resistance

    Science.gov (United States)

    2010-06-02

    size after load increase. Fig. 2.12. Coefficients α, β and γ of TiN–AlN ceramics (a) and of hard alloys (b) in dependence on relative crack length...P286 – FINAL REPORT PAGE 12 02-Jun-10 1. Introduction Ceramic borides, such as hafnium diboride (HfB2) and zirconium diboride (ZrB2...of α, β and γ, carried out for technically important ceramics and hard alloys , showed that the increase of relative crack length c/a corresponds to a

  11. Creep and Oxidation of Hafnium Diboride Based Ultra High Temperature Ceramics at 1500C

    Science.gov (United States)

    2015-12-01

    Poisson’s Ratio 0.12 [52] Young’s Modulus 480 GPa [53] Bulk Modulus 212 GPa [9] Hardness 28 GPa [49] Fracture Toughness 4.0 MPa√m [36] Brittle to...additions of tungsten boride (WB) and tungsten carbide (WC) improved sintering and reduced the grain size of a HfB2 material system with 15% SiC by...oxygen impurities, improve densification, and limit grain growth, thus greatly improving flexural strength. Fracture toughness also improved

  12. Infrared cross sections and global warming potentials of 10 alternative hydrohalocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Clerbaux, C.; Colin, R.; Simon, P.C.; Granier, C.

    1993-01-01

    Absorption cross sections were obtained in the infrared atmospheric window, between 600 and 1500/cm, for 10 alternative hydrohalocarbons: HCFC-22, HCFC-123, HCFC-124, HCFC-141b, HCFC-142b, HCFC-225ca, HCFC-225cb, HFC-125, HFC-134a, and HFC-152a. The measurements were made at three temperatures (287K, 270K and 253K) with a Fourier transform spectrometer operating at 0.03/cm apodized resolution. Integrated cross sections were introduced into a two dimensional radiative chemical dynamical model in order to calculate the global warming potential of each gas.

  13. Properties of new refrigerants and predictions for condensation heat transfer enhancement with low-finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Stegou-Sagia, A. [National Technical University of Athens (Greece). Dept. of Mechanical Engineering

    1996-12-01

    The present article provides a review of thermophysical properties research of environmentally acceptable refrigerants. In recent years, it has become evident that common CFC type refrigerants can cause serious environmental damage when released into the atmosphere. The group of HFCs (HFC-32, HFC-125, HFC-134a, HFC-152a) with no chlorine atom in their chemical formulae and quite short atmospheric lifetime may be promising alternatives to CFCs. A compilation of properties is given which may be used to obtain arithmetic expressions for the vapour pressure, saturated liquid density, viscosity, latent heat of vaporization, saturated liquid thermal conductivity, and surface tension of these hydrofluorocarbons. For easily available comparisons, the results are presented in diagrams illustrating the dependence of thermophysical data on temperature at the saturated state. (author)

  14. Tris(η5-cyclopentadienylhafnium(III

    Directory of Open Access Journals (Sweden)

    Vladimir V. Burlakov

    2011-05-01

    Full Text Available In the crystal structure of the title compound, [Hf(C5H53], three cyclopentadienyl ligands surround the HfIII atom in a trigonal–planar geometry. The molecule lies on a sixfold inversion axis.

  15. Composition effects on mechanical properties of tungsten-rhenium-hafnium-carbon alloys

    Science.gov (United States)

    Witzke, W. R.

    1973-01-01

    The mechanical properties of rod and sheet fabricated from arc melted W-4Re-Hf-C alloys containing up to about 0.8 mol percent hafnium carbide (HfC) were evaluated in the as-worked condition. The DBTT's of electropolished bend and tensile specimens were independent of HfC content in this range but dependent on excess Hf or C above that required for stoichiometric HfC. Low temperature ductility was a maximum at Hf contents slightly in excess of stoichiometric. Variations in high temperature strength were also dependent on excess Hf and C. Maximum creep strengthening also occurred at Hf contents in excess of stoichiometric. Analysis of extracted second phase particles indicated that creep strength was reduced by increasing WC content in the HfC particles.

  16. Transitioning to Low-GWP Alternatives in Motor Vehicle Air Conditioning Systems

    Science.gov (United States)

    This fact sheet provides information on low-GWP alternatives in newly manufactured motor vehicle air conditioning systems. It discusses HFC alternatives, market trends, challenges to market entry for alternatives, and potential solutions.

  17. Transitioning to Low-GWP Alternatives in Residential and Commercial Air Conditioning

    Science.gov (United States)

    This fact sheet provides information on low-GWP alternatives in newly manufactured residential and commercial air conditioning systems. It discusses HFC alternatives, market trends, challenges to market entry for alternatives, and potential solutions.

  18. Research in chemical kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Rowland, F.S.

    1991-01-01

    This report contains sections on the reaction of chlorine atoms with 1,1,1,2-terafluoroethane, abstraction reactions by thermal chlorine atoms with hfc-134a, and chlorine atom reactions with vinyl bromide.

  19. Research in chemical kinetics. Progress report, January 1, 1991--December 31, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Rowland, F.S.

    1991-12-31

    This report contains sections on the reaction of chlorine atoms with 1,1,1,2-terafluoroethane, abstraction reactions by thermal chlorine atoms with hfc-134a, and chlorine atom reactions with vinyl bromide.

  20. 40 CFR 98.151 - Reporting threshold.

    Science.gov (United States)

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING HCFC-22 Production and HFC-23 Destruction § 98.151 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an HCFC-22 production...

  1. Heat Transfer in Nucleate Pool Boiling of Binary and Ternary Refrigerant Mixtures

    Institute of Scientific and Technical Information of China (English)

    赵耀华; 刁彦华; 鹤田隆治; 西川日出男

    2004-01-01

    Heat transfer coefficients in nucleate pool boiling were measured on a horizontal copper surface for refrigerants, HFC-134a, HFC-32, and HFC-125, their binary and ternary mixtures under saturated conditions at 0.9MPa. Compared to pure components, both binary and ternary mixtures showed lower heat transfer coefficients.This deterioration was more pronounced as heat flux was increased. Experimental data were compared with some empirical and semi-empirical correlations available in literature. For binary mixture, the accuracy of the correlations varied considerably with mixtures and the heat flux. Experimental data for HFC-32/134a/125 were also compared with available correlated equation obtained by Thome. For ternary mixture, the boiling range of binary mixture composed by the pure fluids with the lowest and the medium boiling points, and their concentration difference had important effects on boiling heat transfer coefficients.

  2. 混合制冷工质核态沸腾的传热研究%Heat transfer in nucleate pool boiling of binary and ternary refrigerant mixtures

    Institute of Scientific and Technical Information of China (English)

    赵耀华; 刁彦华; 鹤田隆治; 西川日出男

    2004-01-01

    Heat transfer coefficients in nucleate pool boiling were measured on a horizontal copper surface for refrigerants,HFC-134a,HFC-32,and HFC-125,their binary and ternary mixtures under saturated conditions at 0.9MPa.Compared to pure components,both binary and ternary mixtures showed lower heat transfer coefficients.This deterioration was more pronounced as heat flux was increased.Experimental data were compared with some empirical and semi-empirical correlations available in literature.For binary mixture,the accuracy of the correlations varied considerably with mixtures and the heat flux.Experimental data for HFC-32/134a/125 were also compared with available correlated equation obtained by Thome.For ternary mixture,the boiling range of binary mixture composed by the pure fluids with the lowest and the medium boiling points,and their concentration difference had important effects on boiling heat transfer coefficients.

  3. The influence of risk perception on biosafety level-2 laboratory workers' hand-to-face contact behaviors.

    Science.gov (United States)

    Johnston, James D; Eggett, Dennis; Johnson, Michele J; Reading, James C

    2014-01-01

    Pathogen transmission in the laboratory is thought to occur primarily through inhalation of infectious aerosols or by direct contact with mucous membranes on the face. While significant research has focused on controlling inhalation exposures, little has been written about hand contamination and subsequent hand-to-face contact (HFC) transmission. HFC may present a significant risk to workers in biosafety level-2 (BSL-2) laboratories where there is typically no barrier between the workers' hands and face. The purpose of this study was to measure the frequency and location of HFC among BSL-2 workers, and to identify psychosocial factors that influence the behavior. Research workers (N = 93) from 21 BSL-2 laboratories consented to participate in the study. Two study personnel measured workers' HFC behaviors by direct observation during activities related to cell culture maintenance, cell infection, virus harvesting, reagent and media preparation, and tissue processing. Following observations, a survey measuring 11 psychosocial predictors of HFC was administered to participants. Study personnel recorded 396 touches to the face over the course of the study (mean = 2.6 HFCs/hr). Of the 93 subjects, 67 (72%) touched their face at least once, ranging from 0.2-16.0 HFCs/hr. Among those who touched their face, contact with the nose was most common (44.9%), followed by contact with the forehead (36.9%), cheek/chin (12.5%), mouth (4.0%), and eye (1.7%). HFC rates were significantly different across laboratories F(20, 72) = 1.85, p = 0.03. Perceived severity of infection predicted lower rates of HFC (p = 0.03). For every one-point increase in the severity scale, workers had 0.41 fewer HFCs/hr (r = -.27, P protection should be considered as part of the BSL-2 PPE ensemble to prevent HFC.

  4. Influence of the Surface and Structural Characteristics of Activated Carbons on Adsorptive Removal of Halo-Olefinic Impurities from 1,1,1,3,3-Pentafluoropropane

    Institute of Scientific and Technical Information of China (English)

    Bo Zhang; Chuang Zhang; Mingquan Wei

    2014-01-01

    abstract Halo-olefinic impurities in 1,1,1,3,3-pentafluoropropane (HFC-245fa) product used as blowing agents, etc. could damage the human body and must be removed. Activated carbon was treated by HCl, HNO3 and NaOH, respec-tively. The adsorptive performance of unmodified and modified activated carbons for the removal of a low con-tent of 1-chloro-3,3,3-trifluoro-1-propene (HCFC-1233zd), 1,3,3,3-tetrafluoro-1-propene (HFC-1234ze), 1-chloro-1,3,3,3-tetrafluoro-1-propene (HFC-1224zb) and 2-chloro-1,3,3,3-tetrafluoro-1-propene (HFC-1224xe) halo-olefins in the 1,1,1,3,3-pentafluoropropane (HFC-245fa) product was investigated. These halo-olefinic im-purities could be substantially removed from the HFC-245fa product via the adsorption over activated carbon when the adsorption temperature was under 333 K, which can be attributed to theπ-πdispersion interactions between the halo-olefins and carbon graphite layer. The basic surface groups of activated carbon could catalyze the decomposition of HFC-245fa to form HFC-1234ze. However, the significant increase in the amount of surface acidic groups of activated carbon led to a distinct decrease of adsorption capacity due to the reduction in the mi-cropore volume of adsorbent and a decrease in the strength of theπ-πdispersive interactions between halo-olefin molecules and carbon basal. The breakthrough time of halo-olefinic impurities on activated carbon in-creased with the increase of molecular mass and the decrease of molecular symmetry.

  5. Design and methodology of the NorthStar Study

    DEFF Research Database (Denmark)

    Schou, Morten; Gustafsson, Finn; Videbaek, Lars;

    2008-01-01

    Randomized clinical trials have shown that newly discharged and symptomatic patients with chronic heart failure (CHF) benefit from follow-up in a specialized heart failure clinic (HFC). Clinical stable and educated patients are usually discharged from the HFC when on optimal therapy. It is unknown...... if risk stratification using natriuretic peptides could identify patients who would benefit from longer-term follow-up. Furthermore, data on the use of natriuretic peptides for monitoring of stable patients with CHF are sparse....

  6. A Phenomenological Model of the Electrically Stimulated Auditory Nerve Fiber: Temporal and Biphasic Response Properties.

    Science.gov (United States)

    Horne, Colin D F; Sumner, Christian J; Seeber, Bernhard U

    2016-01-01

    We present a phenomenological model of electrically stimulated auditory nerve fibers (ANFs). The model reproduces the probabilistic and temporal properties of the ANF response to both monophasic and biphasic stimuli, in isolation. The main contribution of the model lies in its ability to reproduce statistics of the ANF response (mean latency, jitter, and firing probability) under both monophasic and cathodic-anodic biphasic stimulation, without changing the model's parameters. The response statistics of the model depend on stimulus level and duration of the stimulating pulse, reproducing trends observed in the ANF. In the case of biphasic stimulation, the model reproduces the effects of pseudomonophasic pulse shapes and also the dependence on the interphase gap (IPG) of the stimulus pulse, an effect that is quantitatively reproduced. The model is fitted to ANF data using a procedure that uniquely determines each model parameter. It is thus possible to rapidly parameterize a large population of neurons to reproduce a given set of response statistic distributions. Our work extends the stochastic leaky integrate and fire (SLIF) neuron, a well-studied phenomenological model of the electrically stimulated neuron. We extend the SLIF neuron so as to produce a realistic latency distribution by delaying the moment of spiking. During this delay, spiking may be abolished by anodic current. By this means, the probability of the model neuron responding to a stimulus is reduced when a trailing phase of opposite polarity is introduced. By introducing a minimum wait period that must elapse before a spike may be emitted, the model is able to reproduce the differences in the threshold level observed in the ANF for monophasic and biphasic stimuli. Thus, the ANF response to a large variety of pulse shapes are reproduced correctly by this model.

  7. Effect of atrial natriuretic factor and 8-bromo cyclic guanosine 3':5'-monophosphate on ( sup 3 H)acetylcholine outflow from myenteric-plexus longitudinal muscle of the guinea pig

    Energy Technology Data Exchange (ETDEWEB)

    Matusak, O.; Kuchel, O.; Hamet, P. (Clinical Research Institute of Montreal, Quebec, (Canada))

    1991-04-01

    We report that atrial natriuretic factor (ANF) inhibits electrically induced cholinergic twitches of longitudinal muscle in whole intestinal segments and myenteric-plexus longitudinal muscle (MPLM) strips from the guinea pig ileum. To elucidate the possible presynaptic mechanism of ANF's action, we studied spontaneous and stimulation-evoked radiolabeled acetylcholine (ACh) outflow from MPLM after incubation with ({sup 3}H)choline. We developed a method of mounting and treating MPLM preparations, which allowed us, at the same time, to record isometric contractions and to determine ({sup 3}H)ACh outflow upon electrical stimulation by a train of three pulses. ANF (5 x 10{sup {minus} 8}M), norepinephrine (2 x 10{sup {minus} 7}) M and 8-bromoguanosine 3':5'-cyclic monophosphate (10{sup {minus} 3} M) in nearly equieffective concentrations caused a similar inhibition of cholinergic twitches. However, ANF had no effect on ({sup 3}H)ACh outflow, whereas norepinephrine was found to suppress ({sup 3}H)ACh outflow and 8-bromoguanosine 3':5'-cGMP to enhanced ({sup 3}H)ACh outflow. ANF (5 x 10{sup {minus} 8} M) caused a 7.0-fold increase of cGMP over control values, predominantly in muscle layers, whereas Escherichia coli heat-stable toxin (12.5 U/ml) elicited a 35-fold increment of cGMP in the extramuscular layer. Thus, ANF is able to elevate cGMP in intestinal smooth muscle and to inhibit cholinergic contractions of MPLM. This inhibition is mimicked by exogenous cGMP and by endogenously generated cyclic nucleotides. We suggest that the depressive action of ANF on cholinergic contractions of MPLM is mediated via its postsynaptic impact implicating elevation of cGMP in smooth muscle.

  8. Cytogenetic and chemical detection of human exposure to polyhalogenated aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Lundgren, K.; Collman, G.W.; Wang-Wuu, S.; Tiernan, T.; Taylor, M.; Thompson, C.L.; Lucier, G.W.

    1988-01-01

    Peripheral lymphocytes from Taiwanese women (n = 35) exposed to polychlorinated aromatic hydrocarbons and from matched controls (n = 24) were assessed for the levels of sister chromatid exchanges (SCEs) after a 72-hour incubation of whole blood in the presence or absence of alpha-naphthoflavone (ANF) and for chromosome aberrations after 48 hours of incubation. Serum levels of polychlorinated biphenyl (PCB) congeners were measured for all individuals, and serum levels of several polychlorinated dibenzofurans (PCDFs) were measured for 12 exposed individuals by gas chromatography-mass spectometry. Blood concentrations of total PCBs in the exposed population averaged approximately 15 ppb, whereas mean PCDF values were 14 ppt. Major PCB congeners detected were 2,2' 4,4', 5,5'-hexa CB and 2,2'3,4,4',5-hexa CB. PCDFs detected were primarily 1,2,3,4,7,8,-hexachlorodibenzofuran (10.8 ppt) and 2,3,4,7,8-pentachlorodibenzofuran (2.7 ppt). Average SCE frequencies were 7.61 for controls and 7.30 for exposed individuals when assays were conducted in the absence of ANF, whereas respective values were 8.85 and 10.75 in the presence of ANF. Differences in the level of ANF-induced SCEs between the two populations were highly significant (P less than .001). Moreover, the ANF-induced SCEs were highly correlated with the serum concentrations of total PCBs and of several PCB congeners (P less than .001). Increases in ANF-induced SCEs appeared to be linear up to a PCB concentration of approximately 30 ppb. Chromosome aberration frequencies were similar in control and exposed populations. These studies demonstrate that in vivo exposure to PCBs and PCDFs result in an enhanced sensitivity of lymphocytes to the SCE-causing actions of ANF.

  9. Arc Jet Testing of Hafnium Diboride Based Ultra High Temperature Ceramics

    Science.gov (United States)

    Ellerby, Don; Beckman, Sarah; Irby, Edward; Squire, Tom; Olejniczak, Joe; Johnson, Sylvia M.; Gusman, Michael; Gasch, Matthew

    2003-01-01

    Hafnium Diboride (HFB,) based materials have shown promise for use in a number of high temperature aerospace applications, including rocket nozzles and as leading edges on hypersonic reentry vehicles. The stability of the materials in relevant environments is key to determining their suitability for a particular application. In this program we have been developing HfB2/SiC materials for use as sharp leading edges. The program as a whole included processing and characterization of the HfBJSiC materials. The specific work discussed here will focus on studies of the materials oxidation behavior in simulated reentry environments through arc jet testing. Four flat face models were tested to examine the influence of heat flux and stagnation pressure on the materials oxidation behavior. The results from arc jet testing of two HfB2/SiC cone models will also be discussed. Each cone model was run multiple times with gradually increasing heat fluxes. Total run times on a single cone model exceeded 80 minutes. For both the flat face and cone models surface temperatures well in excess of 2200 C were measured. Post test microstructural examination of the models and correlations with measured temperatures will be discussed.

  10. Heterologous expression of surface-active proteins from barley and filamentous fungi in Pichia pastoris and characterization of their contribution to beer gushing.

    Science.gov (United States)

    Lutterschmid, Georg; Muranyi, Monika; Stübner, Matthias; Vogel, Rudi F; Niessen, Ludwig

    2011-05-14

    The spontaneous over-foaming of beer upon opening, i.e. beer gushing, is an unwanted phenomenon for the brewing industry. Currently, surface-active proteins from filamentous fungi and non-specific lipid transfer proteins (nsLTP1) from barley are discussed as gushing inducers. In our study the class I hydrophobin FcHyd3p from Fusarium culmorum, the class II hydrophobin Hfb2 from Trichoderma reesei, the alkaline foam protein A (AfpA) from F. graminearum and nsLTP1 from Hordeum vulgare cv. Marnie (barley) were heterologously expressed in Pichia pastoris and used in gushing tests. The class I hydrophobin FcHyd3p was unable to induce gushing in beer. The class II hydrophobin Hfb2 was able to induce gushing in beer, but proved to be inhibited by heat treatment as well as by the presence of enriched hop compounds. Both resulted in a reduced gushing potential. AfpA and nsLTP1 exhibited no gushing-inducing potential at the amounts added to beer. Addition of these proteins to beer or carbonated water previously treated with class II hydrophobins revealed a gushing reducing character.

  11. Nanomechanical and nanotribological behaviors of hafnium boride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, Shahla, E-mail: chowdhury.shahla@gmail.com [Department of Mechanical Science and Engineering, University of Illinois at Urbana Champaign, 1206 W Green Street, Urbana, IL 61801 (United States); Department of Mechanical Engineering, Texas A& M University, 3123 TAMU, College Station, TX (United States); Polychronopoulou, Kyriaki, E-mail: kpolychronopoulou@gmail.com [Department of Mechanical Science and Engineering, University of Illinois at Urbana Champaign, 1206 W Green Street, Urbana, IL 61801 (United States); Mechanical Engineering Department, Khalifa University of Science Technology & Research, P.O Box 127788, Abu Dhabi (United Arab Emirates); Cloud, Andrew, E-mail: andrewncloud@gmail.com [Department of Materials Science and Engineering, University of Illinois at Urbana Champaign, 1304 W Green Street, Urbana, IL 61801 (United States); Abelson, John R., E-mail: abelson@illinois.edu [Department of Materials Science and Engineering, University of Illinois at Urbana Champaign, 1304 W Green Street, Urbana, IL 61801 (United States); Polycarpou, Andreas A., E-mail: apolycarpou@tamu.edu [Department of Mechanical Science and Engineering, University of Illinois at Urbana Champaign, 1206 W Green Street, Urbana, IL 61801 (United States); Department of Mechanical Engineering, Texas A& M University, 3123 TAMU, College Station, TX (United States)

    2015-11-30

    Nanocrystalline HfB{sub 2}, HfBN and multilayer HfB{sub 2}/HfBN films were deposited using chemical vapor deposition. Half of the amorphous as-deposited films were subjected to annealing at 700 °C to obtain their annealed equivalent samples. Nanoindentation and nanoscratch experiments were performed to measure their mechanical properties, friction and scratch/wear behavior. The annealed films showed higher hardness values compared to the as-deposited films, with the HfB{sub 2} film exhibiting the highest hardness. All three films exhibited similar shear strength around 3 GPa for as-deposited and 5.5 GPa for annealed films, implying reduced delamination propensity for the annealed samples. The annealed HfBN and multilayer HfB{sub 2}/HfBN films exhibited lower friction and wear, compared to the rest of the films. Specifically, the annealed multilayer HfB{sub 2}/HfBN films, exhibited an order of magnitude lower wear, compared to the HfB{sub 2} films, making them excellent candidates for low friction and low wear hard coating applications. - Highlights: • Hard, dense thin films of HfB2/HfBN were deposited using chemical vapor deposition. • Annealed films exhibited high shear strength, and thus reduced propensity to delamination. • Hardness values alone do not correlate with friction and wear performance. • Annealed multi-layered HfB2/HfBN films exhibited outstanding friction and wear resistance.

  12. Testing the influence of family structure and outbreeding depression on heterozygosity-fitness correlations in small populations.

    Science.gov (United States)

    Jourdan-Pineau, Helene; Folly, Joy; Crochet, Pierre-Andre; David, Patrice

    2012-11-01

    Theory predicts that positive heterozygosity-fitness correlations (HFCs) arise as a consequence of inbreeding, which is often assumed to have a strong impact in small, fragmented populations. Yet according to empirical data, HFC in such populations seem highly variable and unpredictable. We here discuss two overlooked phenomena that may contribute to this variation. First, in a small population, each generation may consist of a few families. This generates random correlations between particular alleles and fitness (AFCs, allele-fitness correlations) and results in too liberal tests for HFC. Second, in some contexts, small populations receiving immigrants may be more impacted by outbreeding depression than by inbreeding depression, resulting in negative rather than positive HFC. We investigated these processes through a case study in tadpole cohorts of Pelodytes punctatus living in small ponds. We provide evidence for a strong family structure and significant AFC in this system, as well as an example of negative HFC. By simulations, we show that this negative HFC cannot be a spurious effect of family structure, and therefore reflects outbreeding depression in the studied population. Our example suggests that a detailed examination of AFC and HFC patterns can provide valuable insights into the internal genetic structure and sources of fitness variation in small populations.

  13. Thermal Analysis of Tantalum Carbide-Hafnium Carbide Solid Solutions from Room Temperature to 1400 °C

    Directory of Open Access Journals (Sweden)

    Cheng Zhang

    2017-07-01

    Full Text Available The thermogravimetric analysis on TaC, HfC, and their solid solutions has been carried out in air up to 1400 °C. Three solid solution compositions have been chosen: 80TaC-20 vol % HfC (T80H20, 50TaC-50 vol % HfC (T50H50, and 20TaC-80 vol % HfC (T20H80, in addition to pure TaC and HfC. Solid solutions exhibit better oxidation resistance than the pure carbides. The onset of oxidation is delayed in solid solutions from 750 °C for pure TaC, to 940 °C for the T50H50 sample. Moreover, T50H50 samples display the highest resistance to oxidation with the retention of the initial carbides. The oxide scale formed on the T50H50 sample displays mechanical integrity to prevent the oxidation of the underlying carbide solid solution. The improved oxidation resistance of the solid solution is attributed to the reaction between Ta2O5 and HfC, which stabilizes the volume changes induced by the formation of Ta2O5 and diminishes the generation of gaseous products. Also, the formation of solid solutions disturbs the atomic arrangement inside the lattice, which delays the reaction between Ta and O. Both of these mechanisms lead to the improved oxidation resistances of TaC-HfC solid solutions.

  14. Highly porous activated carbon based adsorption cooling system employing difluoromethane and a mixture of pentafluoroethane and difluoromethane

    Science.gov (United States)

    Askalany, Ahmed A.; Saha, Bidyut B.

    2017-01-01

    This paper presents a simulation for a low-grade thermally powered two-beds adsorption cooling system employing HFC-32 and a mixture of HFC-32 and HFC-125 (HFC-410a) with activated carbon of type Maxsorb III. The present simulation model adopts experimentally measured adsorption isotherms, adsorption kinetics and isosteric heat of adsorption data. Effect of operating conditions (mass flow rate of hot water, driving heat source temperature and evaporator temperature) on the system performance has been studied in detail. The simulation results showed that the system could be powered by low-grade heat source temperature (below 85 °C). AC/HFC-32 and AC/HFC-410a adsorption cooling cycles achieved close specific cooling power and coefficient of performance values of 0.15 kW/kg and 0.3, respectively at a regeneration temperature of 90 °C along with evaporator temperature of 10 °C. The investigated semi continuous adsorption cooling system could produce a cooling power of 9 kW.

  15. Involvement of peroxisome proliferator-activated receptors in cardiac and vascular remodeling in a novel minipig model of insulin resistance and atherosclerosis induced by consumption of a high-fat/cholesterol diet.

    Science.gov (United States)

    Yongming, Pan; Zhaowei, Cai; Yichao, Ma; Keyan, Zhu; Liang, Chen; Fangming, Chen; Xiaoping, Xu; Quanxin, Ma; Minli, Chen

    2015-01-16

    A long-term high-fat/cholesterol (HFC) diet leads to insulin resistance (IR), which is associated with inflammation, atherosclerosis (AS), cardiac sympathovagal imbalance, and cardiac dysfunction. Peroxisome proliferator-activated receptors (PPARs) and nuclear factor ĸB (NF-κB) are involved in the development of IR-AS. Thus, we elucidated the pathological molecular mechanism of IR-AS by feeding an HFC diet to Tibetan minipigs to induce IR and AS. Male Tibetan minipigs were fed either a normal diet or an HFC diet for 24 weeks. Thereafter, the minipigs were tested for physiological and biochemical blood indices, blood pressure, cardiac function, glucose tolerance, heart rate variability (HRV), and PPAR-associated gene and protein expression levels. HFC-fed minipigs exhibited IR through increased body weight, fasting blood glucose levels, plasma cholesterol and its composition, and insulin and free fatty acid (FFA) levels; decreased insulin sensitivity; impaired glucose tolerance; and hypertension. Increased C-reactive protein (CRP) levels, cardiac dysfunction, depressed HRV, and the up-regulation of PPAR expression in the abdominal aorta concomitant with down-regulation in the heart tissue were observed in HFC-fed minipigs. Furthermore, the levels of NF-κBp65, IL-1β, TNF-α, MCP-1, VCAM-1, ICAM-1, MMP-9, and CRP proteins were also significantly increased. These data suggest that HFC-fed Tibetan minipigs develop IR and AS and that PPARs are involved in cardiovascular remodeling and impaired function.

  16. Fast negative feedback enables mammalian auditory nerve fibers to encode a wide dynamic range of sound intensities.

    Directory of Open Access Journals (Sweden)

    Mark Ospeck

    Full Text Available Mammalian auditory nerve fibers (ANF are remarkable for being able to encode a 40 dB, or hundred fold, range of sound pressure levels into their firing rate. Most of the fibers are very sensitive and raise their quiescent spike rate by a small amount for a faint sound at auditory threshold. Then as the sound intensity is increased, they slowly increase their spike rate, with some fibers going up as high as ∼300 Hz. In this way mammals are able to combine sensitivity and wide dynamic range. They are also able to discern sounds embedded within background noise. ANF receive efferent feedback, which suggests that the fibers are readjusted according to the background noise in order to maximize the information content of their auditory spike trains. Inner hair cells activate currents in the unmyelinated distal dendrites of ANF where sound intensity is rate-coded into action potentials. We model this spike generator compartment as an attenuator that employs fast negative feedback. Input current induces rapid and proportional leak currents. This way ANF are able to have a linear frequency to input current (f-I curve that has a wide dynamic range. The ANF spike generator remains very sensitive to threshold currents, but efferent feedback is able to lower its gain in response to noise.

  17. Bassoon-disruption slows vesicle replenishment and induces homeostatic plasticity at a CNS synapse.

    Science.gov (United States)

    Mendoza Schulz, Alejandro; Jing, Zhizi; Sánchez Caro, Juan María; Wetzel, Friederike; Dresbach, Thomas; Strenzke, Nicola; Wichmann, Carolin; Moser, Tobias

    2014-03-03

    Endbulb of Held terminals of auditory nerve fibers (ANF) transmit auditory information at hundreds per second to bushy cells (BCs) in the anteroventral cochlear nucleus (AVCN). Here, we studied the structure and function of endbulb synapses in mice that lack the presynaptic scaffold bassoon and exhibit reduced ANF input into the AVCN. Endbulb terminals and active zones were normal in number and vesicle complement. Postsynaptic densities, quantal size and vesicular release probability were increased while vesicle replenishment and the standing pool of readily releasable vesicles were reduced. These opposing effects canceled each other out for the first evoked EPSC, which showed unaltered amplitude. We propose that ANF activity deprivation drives homeostatic plasticity in the AVCN involving synaptic upscaling and increased intrinsic BC excitability. In vivo recordings from individual mutant BCs demonstrated a slightly improved response at sound onset compared to ANF, likely reflecting the combined effects of ANF convergence and homeostatic plasticity. Further, we conclude that bassoon promotes vesicular replenishment and, consequently, a large standing pool of readily releasable synaptic vesicles at the endbulb synapse.

  18. Burnout in nursing.

    Science.gov (United States)

    Patrick, Kent; Lavery, Judy F

    2007-01-01

    Previous research has suggested that organisational change can contribute to stress-related outcomes for workers. Burnout, one such stress-related outcome, has been conceptualised as a multidimensional construct consisting of emotional exhaustion, depersonalisation and reduced personal accomplishment. Many health care organisations have undergone substantial organisational change over the last decade. The purpose of this study was to assess levels of burnout in nurses and to ascertain if there were individual or work characteristics that were associated with this syndrome. Randomised survey methodology. Registered nurses (Division 1) in Victoria who were ANF members. A random sample of 574 Victorian ANF nurse members. The assessment of levels of burnout in Victorian ANF nurse members and the identification of individual or work characteristics that may be associated with it. Victorian ANF nurse members exhibited lower depersonalisation and higher personal accomplishment compared to medical and overall normative data. Increasing age and fewer working hours were associated with lower levels of emotional exhaustion and depersonalisation. Working overtime was positively associated with emotional exhaustion however further analyses demonstrated that those who worked overtime voluntarily did not differ from workers not working overtime. However feeling pressured/expected to work overtime was positively associated with emotional exhaustion and depersonalisation. Victorian ANF nurse members were not experiencing high levels of burnout. However the study highlighted the need for health care management to recognise the importance of working reasonable hours and in particular, to understand the potential detrimental effect that having to work pressured or unexpected overtime has on staff.

  19. The endocrine system in space flight

    Science.gov (United States)

    Leach, C. S.; Johnson, P. C.; Cintron, N. M.

    1988-01-01

    A trial natriuretic factor (ANF), a hormone recently shown to regulate sodium and water excretion, has been measured in blood specimens obtained during flight. After 30 or 42 h of weightlessness, mean ANF was elevated. After 175 or 180 h, ANF has increased by 59 percent, and it changed little between that time and soon after landing. There is probably an increase in ANF early inflight associated with the fluid shift, followed by a compensatory decrease in blood volume. Increased renal blood flow may cause the later ANF decrease. Erythropoietin (Ep), a hormone involved in the control of red blood cell proudction, was measured in blood samples taken during the first Spacelab mission and was significantly decreased on the second day of flight, suggesting also an increase in renal blood flow. Spacelab-2 investigators report that the active vitamin D metabolite 1 alpha, 25-dihydroxyvitamin D-3 increased early in the flight, indicating that a stimulus for increased bone resorption occurs by 30 h after launch.

  20. The endocrine system in space flight

    Science.gov (United States)

    Leach, C. S.; Johnson, P. C.; Cintron, N. M.

    Hormones are important effectors of the body's response to microgravity in the areas of fluid and electrolyte metabolism, erythropoiesis, and calcium metabolism. For many years antidiuretic hormone, cortisol and aldosterone have been considered the hormones most important for regulation of body fluid volume and blood levels of electrolytes, but they cannot account totally for losses of fluid and electrolytes during space flight. We have now measured atrial natriuretic factor (ANF), a hormone recently shown to regulate sodium and water excretion, in blood specimens obtained during flight. After 30 or 42 h of weightlessness, mean ANF was elevated. After 175 or 180 h, ANF had decreased by 59%, and it changed little between that time and soon after landing. There is probably an increase in ANF early inflight associated with the fluid shift, followed by a compensatory decrease in blood volume. Increased renal blood flow may cause the later ANF decrease. Erythropoietin (Ep), a hormone involved in the control of red blood cell production, was measured in blood samples taken during the first Spacelab mission and was significantly decreased on the second day of flight, suggesting also an increase in renal blood flow. Spacelab-2 investigators report that the active vitamin D metabolite 1α, 25-dihydroxyvitamin D 3 increased early in the flight, indicating that a stimulus for increased bone resorption occurs by 30 h after launch.

  1. Glucocorticoids and atrial natriuretic factor receptors on vascular smooth muscle.

    Science.gov (United States)

    Yasunari, K; Kohno, M; Murakawa, K; Yokokawa, K; Takeda, T

    1990-11-01

    The effect of glucocorticoids on the atrial natriuretic factor (ANF)-mediated formation of cyclic guanosine monophosphate (cGMP) by intact vascular smooth muscle cells (VSMC) was studied in rats. Cultured VSMC were obtained from the renal arteries of 14-week-old Wistar rats by the explant method. Micromolar concentrations of dexamethasone, given as pretreatment for 48 hours, suppressed the ANF-mediated response. The dexamethasone-induced suppression was detectable at 6 hours and reached a maximum 24 hours after administration in a dose-dependent manner. Inhibitors of protein synthesis blocked this effect of the glucocorticoid. The basal activity of guanylate cyclase in the dexamethasone-treated cells was lower than in the control cells. Other steroids having glucocorticoid action mimicked this suppression of the ANF-mediated response. This suppression was blocked by a glucocorticoid receptor antagonist. The results suggest that glucocorticoids suppress ANF-mediated cGMP formation by VSMC through glucocorticoid type II receptors and the induction of protein synthesis. Suppression of the ANF-mediated response may play a role in glucocorticoid-induced hypertension.

  2. The Effects and Mechanism of C-Type Natriuretic Peptides on Swine Heart Coronary Artery%C型利钠肽扩张猪冠状动脉的作用及机制的研究

    Institute of Scientific and Technical Information of China (English)

    舒燕; 李其勇; 姜荣建; 孔洪

    2015-01-01

    Objective Investigate the influences of C-natriuretic peptides on langendorff-perfused swine heart coronary. Reveal the underlying vasodilatory ability and mechanism of C-natriuretic peptides. Methods Three different groups named the C-Natriuretic Group ( CNP Group) , the Nitroglycerol Group ( GTN Group) , and the NPR-C Receptor Agonist Group ( cANF4-23 Group) were set up.①Each of above groups was perfused by solution of NE,and then was perfused by GTN、CNP and cANF4-23. The vasodilatory influences of CNP and GTN on swine heart coronary arteries and whether cANF4-23 were involved in this procedure were studied .②cANF4-28 was given first, and then CNP were added, the vasodilatory influences were observed.③K + solutions ( at the concentration of 80 nM) were used to preserve the arteries, so they were all in contracted state, and then CNP and cANF4-23 were added, and the vasodilatory influences were observed. Results ①CNP,GTN and cANF4-23 all had significant vasodilatory in-fluences on swine heart coronary artery. no significant difference of vasodilation influences was found between CNP Group and cANF4-23 Group(P>0. 05). The vasodilatory influence of CNP Group was weaker than GTN Group (P<0. 05).②In cANF4-28 preserved arteries, The largest circulus vasculosus vasodilatory ratios of CNP was significantly weaker than Control Group , and had statistical significance (P<0. 01).③The vasodilatory influences of CNP and cANF4-23 Groups were significantly decreased in high concentration K + solution in contrast with the Control Group ( P<0. 05 ) , but not blocked. Conclusions C- Natriuretic peptides have significant vasodilatory influence on swine heart coronary artery. The vasodilatory mechanism of CNP involves NPR-C. NPR-C is not only the well-known clearance receptor, but also leads to vasodilation of the coronary artery. the vasodilatory of CNP/NPR-C sig-naling involves K+ channel.%目的:本研究通过离体灌流方法观察C型利钠肽( CNP)对离体

  3. Health facility committees and facility management - exploring the nature and depth of their roles in Coast Province, Kenya.

    Science.gov (United States)

    Goodman, Catherine; Opwora, Antony; Kabare, Margaret; Molyneux, Sassy

    2011-09-22

    Community participation has been emphasized internationally as a way of enhancing accountability, as well as a means to enhance health goals in terms of coverage, access and effective utilization. In rural health facilities in Kenya, initiatives to increase community accountability have focused on Health Facility Committees (HFCs). In Coast Province the role of HFCs has been expanded with the introduction of direct funding of rural facilities. We explored the nature and depth of managerial engagement of HFCs at the facility level in two rural districts in this Coastal setting, and how this has contributed to community accountability We conducted structured interviews with the health worker in-charge and with patients in 30 health centres and dispensaries. These data were supplemented with in-depth interviews with district managers, and with health workers and HFC members in 12 health centres and dispensaries. In-depth interviews with health workers and HFC members included a participatory exercise to stimulate discussion of the nature and depth of their roles in facility management. HFCs were generally functioning well and played an important role in facility operations. The breadth and depth of engagement had reportedly increased after the introduction of direct funding of health facilities which allowed HFCs to manage their own budgets. Although relations with facility staff were generally good, some mistrust was expressed between HFC members and health workers, and between HFC members and the broader community, partially reflecting a lack of clarity in HFC roles. Moreover, over half of exit interviewees were not aware of the HFC's existence. Women and less well-educated respondents were particularly unlikely to know about the HFC. There is potential for HFCs to play an active and important role in health facility management, particularly where they have control over some facility level resources. However, to optimise their contribution, efforts are needed to

  4. Health facility committees and facility management - exploring the nature and depth of their roles in Coast Province, Kenya

    Directory of Open Access Journals (Sweden)

    Kabare Margaret

    2011-09-01

    Full Text Available Abstract Background Community participation has been emphasized internationally as a way of enhancing accountability, as well as a means to enhance health goals in terms of coverage, access and effective utilization. In rural health facilities in Kenya, initiatives to increase community accountability have focused on Health Facility Committees (HFCs. In Coast Province the role of HFCs has been expanded with the introduction of direct funding of rural facilities. We explored the nature and depth of managerial engagement of HFCs at the facility level in two rural districts in this Coastal setting, and how this has contributed to community accountability Methods We conducted structured interviews with the health worker in-charge and with patients in 30 health centres and dispensaries. These data were supplemented with in-depth interviews with district managers, and with health workers and HFC members in 12 health centres and dispensaries. In-depth interviews with health workers and HFC members included a participatory exercise to stimulate discussion of the nature and depth of their roles in facility management. Results HFCs were generally functioning well and played an important role in facility operations. The breadth and depth of engagement had reportedly increased after the introduction of direct funding of health facilities which allowed HFCs to manage their own budgets. Although relations with facility staff were generally good, some mistrust was expressed between HFC members and health workers, and between HFC members and the broader community, partially reflecting a lack of clarity in HFC roles. Moreover, over half of exit interviewees were not aware of the HFC's existence. Women and less well-educated respondents were particularly unlikely to know about the HFC. Conclusions There is potential for HFCs to play an active and important role in health facility management, particularly where they have control over some facility level resources

  5. Development of a nascent galectin-1 chimeric molecule for studying the role of leukocyte galectin-1 ligands and immune disease modulation.

    Science.gov (United States)

    Cedeno-Laurent, Filiberto; Barthel, Steven R; Opperman, Matthew J; Lee, David M; Clark, Rachael A; Dimitroff, Charles J

    2010-10-15

    Galectin-1 (Gal-1), a β-galactoside-binding lectin, plays a profound role in modulating adaptive immune responses by altering the phenotype and fate of T cells. Experimental data showing recombinant Gal-1 (rGal-1) efficacy on T cell viability and cytokine production, nevertheless, is controversial due to the necessity of using stabilizing chemicals to help retain Gal-1 structure and function. To address this drawback, we developed a mouse Gal-1 human Ig chimera (Gal-1hFc) that did not need chemical stabilization for Gal-1 ligand recognition, apoptosis induction, and cytokine modulation in a variety of leukocyte models. At high concentrations, Gal-1hFc induced apoptosis in Gal-1 ligand(+) Th1 and Th17 cells, leukemic cells, and granulocytes from synovial fluids of patients with rheumatoid arthritis. Importantly, at low, more physiologic concentrations, Gal-1hFc retained its homodimeric form without losing functionality. Not only did Gal-1hFc-binding trigger IL-10 and Th2 cytokine expression in activated T cells, but members of the CD28 family and several other immunomodulatory molecules were upregulated. In a mouse model of contact hypersensitivity, we found that a non-Fc receptor-binding isoform of Gal-1hFc, Gal-1hFc2, alleviated T cell-dependent inflammation by increasing IL-4(+), IL-10(+), TGF-β(+), and CD25(high)/FoxP3(+) T cells, and by decreasing IFN-γ(+) and IL-17(+) T cells. Moreover, in human skin-resident T cell cultures, Gal-1hFc diminished IL-17(+) T cells and increased IL-4(+) and IL-10(+) T cells. Gal-1hFc will not only be a useful new tool for investigating the role of Gal-1 ligands in leukocyte death and cytokine stimulation, but for studying how Gal-1-Gal-1 ligand binding shapes the intensity of immune responses.

  6. Combined high-fat diet and sustained high sucrose consumption promotes NAFLD in a murine model.

    Science.gov (United States)

    Torres-Villalobos, Gonzalo; Hamdan-Pérez, Nashla; Tovar, Armando R; Ordaz-Nava, Guillermo; Martínez-Benítez, Braulio; Torre-Villalvazo, Iván; Morán-Ramos, Sofía; Díaz-Villaseñor, Andrea; Noriega, Lilia G; Hiriart, Marcia; Medina-Santillán, Roberto; Castillo-Hernandez, María del Carmen; Méndez-Sánchez, Nahum; Uribe, Misael; Torres, Nimbe

    2015-01-01

    The study of NAFLD in humans has several limitations. Using murine models helps to understand disease pathogenesis. Evaluate the impact of 4 different diets in the production of NAFLD with emphasis on a combined high-fat plus sustained high sucrose consumption. Eight week-old male Wistar rats were divided in four groups and fed for 90 days with the following diets: 1) Control chow diet (C); 2) High-fat cholesterol diet (HFC) + 5% sucrose in drinking water. 3) High-fat cornstarch diet (HFCO) + 5% sucrose in drinking water. 4) Chow diet + 20% sucrose in drinking water (HSD). Metabolic changes, leptin levels, liver histology, hepatic and plasma lipid composition, fasting plasma glucose and insulin and liver gene expression of FAS, SREBP-1 and PPAR-α were evaluated. The HFC diet had the highest grade of steatosis (grade 2 of 3) and HSD showed also steatosis (grade 1). Liver weight TG and colesterol concentrations in liver were greater in the HFC diet. There were no increased levels of iron in the liver. Rats in HFC gained significantly more weight (P < 0.001). All experimental groups showed fasting hyperglycemia. HFC had the highest glucose level (158.5 ± 7 mg/dL) (P < 0.005). The HSD and the HFCO diets developed also hyperglycemia. HSD had significantly higher fasting hyperinsulinemia. Serum leptin was higher in the HFC diet (p = 0.001). In conclusion, the HFC diet with combination of high fat and high sucrose is more effective in producing NAFLD compared with a high sucrose diet only.

  7. Analysis and Design of Notch Filter-Based PLLs for Grid-Connected Applications Electric Power Systems Research

    DEFF Research Database (Denmark)

    Khazraj, Hesam; Silva, Filipe Miguel Faria da; Bak, Claus Leth

    2017-01-01

    Using multiple notch filters (NFs) inside the control loop of a standard PLL is a basic strategy to improve its filtering capability. Often, adaptive NFs (ANFs) are employed for this purpose as they can block the disturbance components even under off-nominal grid frequencies. This advantage...... is at the cost of a rather considerable increase in the PLL implementation complexity and computational effort, particularly when ANFs have their own frequency estimation mechanism. The non-adaptive NFs (NNFs), contrary to ANFs, are easy to implement. They, however, have received a little attention in PLL...... applications. Therefore, their performance characteristics are rather unclear. To gain insight about the advantages and disadvantages of NNF-based PLLs (NNF-PLLs), analysis and design of these PLLs is conducted in this paper. This procedure includes: (1) selecting the appropriate number of NNFs inside the PLL...

  8. DS/EN 1997

    DEFF Research Database (Denmark)

    Sørensen, Carsten Steen; Hansen, Per Bjerregaard; Jensen, Lars Ravn

    Dette nationale anneks omhandler de punkter i DS/EN 1997-1, hvor det er tilladt at foretage nationale valg. De anførte nationale valg gælder for geotekniske konstruktioner, der opføres i Danmark. De nationale valg kan være i form af nationalt gældende værdier, valgte metoder mellem de i DS/EN 1997......-1 angivne metoder eller tilføjelse af supplerende informationer. I dette nationale anneks er kun anført punkter, hvor der er foretaget valg, der adskiller sig fra de i DS/EN 1997-1 anbefalede værdier, metoder eller lignende. Det betyder, at for de punkter, hvor der intet er anført i dette dokument, gælder...... de i DS/EN 1997-1 anbefalede værdier, metoder eller lignende....

  9. Caffeine-induced diuresis and atrial natriuretic peptides.

    Science.gov (United States)

    Nussberger, J; Mooser, V; Maridor, G; Juillerat, L; Waeber, B; Brunner, H R

    1990-05-01

    After a single-blind, randomized, cross-over protocol using decaffeinated coffee in a control experiment, the effect of an oral 250-mg caffeine dose on plasma immunoreactive atrial natriuretic peptide (ANF) was assessed in eight healthy students who had been on a methylxanthine-free diet for 1 week. One to 2 h after caffeine ingestion, both systolic blood pressure (SBP) and diastolic BP (DBP) increased by 12 mm Hg while heart rate (HR) also tended to increase. An increase in diuresis and in urinary sodium, potassium, and osmol excretion was observed within 1 h. Decaffeinated coffee induced no change in any of these parameters. Plasma epinephrine (EPI) increased gradually from 16.6 +/- 3.2 pg/ml (mean +/- SEM) to 45.1 +/- 7.9 pg/ml within 2 h after caffeine ingestion, but did not change after decaffeinated coffee (p less than 0.001). Plasma norepinephrine (NE), renin activity (PRA), aldosterone, and vasopressin remained unchanged. Plasma ANF was measured by radioimmunoassay (RIA) using an extremely sensitive antiserum (Kd = 10(-12) M) after rapid and virtually complete (90-103%) extraction from plasma. In 0.2 ml plasma, the theoretical detection limit is 1.1 fmol/ml. Normal plasma ANF concentrations in supine subjects were 17.9 +/- 8.1 fmol/ml (mean +/- SD) and 11.0 +/- 3.3 fmol/ml in subjects in the upright position. Plasma ANF levels were not affected by coffee drinking. In conclusion, by using a new and sensitive assay for plasma ANF, we did not find that caffeine-induced diuresis is mediated by ANF.

  10. El corazón endocrino y el proceso inflamatorio

    OpenAIRE

    Tsuneo Ogawa; de Bold, Adolfo J

    2013-01-01

    El corazón endocrino, a través de sus hormonas polipéptidas atrial natriuretic factor (ANF o ANP) y brain natriuretic peptide (BNP), contribuye a regular la precarga y la poscarga cardiacas. Otras importantes funciones se han descubierto recientemente incluyendo interacciones con el sistema inmunológico. Los niveles plasmáticos de BNP, no así los de ANF, aumentan durante un episodio de rechazo agudo del corazón alotransplantado pero retornan a niveles anteriores al episodio de rechazo después...

  11. Nøj, det' for børn

    DEFF Research Database (Denmark)

    Munk, Kasper Green

    2016-01-01

    Genopdaget tysk reportageroman dykker ned livet i Berlins underverden på tærsklen til nazisternes magtovertagelse. Men blandingen af hårdkogt drama, anfægtet patos og muntert børnetimesprog efterlader et mærkværdigt indtryk.......Genopdaget tysk reportageroman dykker ned livet i Berlins underverden på tærsklen til nazisternes magtovertagelse. Men blandingen af hårdkogt drama, anfægtet patos og muntert børnetimesprog efterlader et mærkværdigt indtryk....

  12. Detección, identificación, intervención y gestión del amianto existente en los edificios de la UPCT

    OpenAIRE

    Sánchez Conesa, Tomás

    2012-01-01

    El amianto o asbesto (denominaciones de origen griego, cuyo significado es amianto‐incorruptible y asbestos‐inextinguible) es una sustancia mineral natural (silicato fibroso), con dos grupos mineralógicos: serpentinos y anfíboles, que se extrae de la roca en minas de distintos países, principalmente, Canadá, Rusia, Brasil, Australia y algunas zonas de África. El crisotilo pertenece al grupo de las serpentinas; los otros tipos de amianto son del grupo de los anfíboles. Las rocas...

  13. Combustion efficiency and altitude operational limits of three liquid hydrocarbon fuels having high volumetric energy content in a J33 single combustor

    Science.gov (United States)

    Stricker, Edward G

    1950-01-01

    Combustion efficiency and altitude operational limits were determined in a J33 single combustor for AN-F-58 fuel and three liquid hydrocarbon fuels having high volumetric energy content (decalin, tetralin, and monomethylnaphthalene) at simulated altitude and combustor inlet-air conditions. At the conditions investigated, the combustion efficiency for the four fuels generally decreased with an increase in volumetric energy content. The altitude operational limits for decalin and tetralin fuels were higher than for AN-F-58 fuel; monomethylnaphthalene fuel gave the lowest altitude operational limit.

  14. Detección, identificación, intervención y gestión del amianto existente en los edificios de la UPCT

    OpenAIRE

    Sánchez Conesa, Tomás

    2012-01-01

    El amianto o asbesto (denominaciones de origen griego, cuyo significado es amianto‐incorruptible y asbestos‐inextinguible) es una sustancia mineral natural (silicato fibroso), con dos grupos mineralógicos: serpentinos y anfíboles, que se extrae de la roca en minas de distintos países, principalmente, Canadá, Rusia, Brasil, Australia y algunas zonas de África. El crisotilo pertenece al grupo de las serpentinas; los otros tipos de amianto son del grupo de los anfíboles. Las rocas...

  15. Mode og mozzarella

    DEFF Research Database (Denmark)

    Nielsen, Jakob Isak

    2013-01-01

    Under en samtale i Paolo Sorrentinos La grande bellezza/da. Den store skønhed (2013) anføres det, at Italiens primære eksportvarer er mode og mozzarella. Selve filmen vidner om, at Italien har andet at byde på – heriblandt filmkunst og Roms righoldige kulturhistorie.......Under en samtale i Paolo Sorrentinos La grande bellezza/da. Den store skønhed (2013) anføres det, at Italiens primære eksportvarer er mode og mozzarella. Selve filmen vidner om, at Italien har andet at byde på – heriblandt filmkunst og Roms righoldige kulturhistorie....

  16. Design of pH sensitive binding proteins from the hyperthermophilic Sso7d scaffold.

    Directory of Open Access Journals (Sweden)

    Nimish Gera

    Full Text Available We have engineered pH sensitive binding proteins for the Fc portion of human immunoglobulin G (hIgG (hFc using two different strategies - histidine scanning and random mutagenesis. We obtained an hFc-binding protein, Sso7d-hFc, through mutagenesis of the Sso7d protein from the hyperthermophilic archaeon Sulfolobus solfataricus; Sso7d-hFc was isolated from a combinatorial library of Sso7d mutants using yeast surface display. Subsequently, we identified a pH sensitive mutant, Sso7d-his-hFc, through systematic evaluation of Sso7d-hFc mutants containing single histidine substitutions. In parallel, we also developed a yeast display screening strategy to isolate a different pH sensitive hFc binder, Sso7d-ev-hFc, from a library of mutants obtained by random mutagenesis of a pool of hFc binders. In contrast to Sso7d-hFc, both Sso7d-his-hFc and Sso7d-ev-hFc have a higher binding affinity for hFc at pH 7.4 than at pH 4.5. The Sso7d-mutant hFc binders can be recombinantly expressed at high yield in E. coli and are monomeric in solution. They bind an epitope in the CH3 domain of hFc that has high sequence homology in all four hIgG isotypes (hIgG(1-4, and recognize hIgG(1-4 as well as deglycosylated hIgG in western blotting assays. pH sensitive hFc binders are attractive candidates for use in chromatography, to achieve elution of IgG under milder pH conditions. However, the surface density of immobilized hFc binders, as well as the avidity effect arising from the multivalent interaction of dimeric hFc with the capture surface, influences the pH dependence of dissociation from the capture surface. Therefore, further studies are needed to evaluate if the Sso7d mutants identified in this study are indeed useful as affinity ligands in chromatography.

  17. Severe symptoms of short tear break-up time dry eye are associated with accommodative microfluctuations

    Directory of Open Access Journals (Sweden)

    Kaido M

    2017-05-01

    Full Text Available Minako Kaido,1,2 Motoko Kawashima,1 Reiko Ishida,1,3 Kazuo Tsubota1 1Department of Ophthalmology, Keio University School of Medicine, Tokyo, 2Wada Eye Clinic, Chiba, 3Ishida Eye Clinic, Shizuoka, Japan Aim: Validating the hypothesis that accommodative microfluctuations (AMFs may be associated with severe symptoms in short tear break-up time (BUT dry eye (DE. Methods: This study included 12 subjects with short BUT DE (age: 49.6±18.3 years. Diagnoses were performed based on the presence of DE symptoms, BUT ≤5 s, Schirmer score >5 mm, and negative keratoconjunctival epithelial damage. Tear evaluation, AMF, and functional visual acuity (VA examinations were conducted before and after DE treatment. The AMF parameters evaluated were: total high-frequency component (HFC, HFC with low accommodation for the task of staring into the distance (HFC1, HFC with high accommodation for deskwork (HFC2. A subjective questionnaire of DE symptoms was also performed. Results: Mean BUT increased from 1.9±2.0 to 6.4±2.5 s after treatment (P<0.05. The mean logarithm of the minimum angle of resolution functional VA significantly improved (from 0.19±0.19 to 0.12±0.17; P<0.05. Mean power spectrum values for total HFC and HFC1 decreased (from 61.3±5.7 to 53.8±6.6 dB and from 62.9±10.5 to 52.4±6.2 dB, respectively; P<0.05, while the mean HFC2 power spectrum values did not differ before and after treatment (P>0.05. Subjective DE symptoms were reduced in nine patients. Conclusion: Along with the improvement of BUT after treatment, DE symptoms diminished and HFC1 and functional VA improved, suggesting that tear film instability is associated with deterioration of functional VA, AMF, and DE symptoms. Keywords: accommodative microfluctuation, ciliary muscle spasm, dry eye, ocular fatigue, tear break-up time, functional visual acuity 

  18. New SI-traceable reference gas mixtures for fluorinated gases at atmospheric concentration

    Science.gov (United States)

    Guillevic, Myriam; Wyss, Simon A.; Pascale, Céline; Vollmer, Martin K.; Niederhauser, Bernhard; Reimann, Stefan

    2016-04-01

    In order to better support the monitoring of greenhouse gases in the atmosphere, we develop a method to produce reference gas mixtures for fluorinated gases (F-gases, i.e. gases containing fluorine atoms) in a SI-traceable way, meaning that the amount of substance fraction in mole per mole is traceable to SI-units. These research activities are conducted in the framework of the HIGHGAS and AtmoChem-ECV projects. First, single-component mixtures in synthetic air at ~85 nmol/mol (ppb) are generated for HFC-125 (pentafluoroethane, a widely used HFC) and HFC-1234yf (2,3,3,3-tetrafluoropropene, a car air conditioner fluid of growing importance). These mixtures are first dynamically produced by permeation: a permeator containing the pure substance loses mass linearly over time under a constant gas flow, in the permeation chamber of a magnetic suspension balance, which is regularly calibrated. This primary mixture is then pressurised into Silconert2000-coated stainless steel cylinders by cryo-filling. In a second step these mixtures are dynamically diluted using 2 subsequent dilution steps piloted by mass flow controllers (MFC) and pressure controllers. The assigned mixture concentration is calculated mostly based on the permeator mass loss, on the carrier gas purity and on the MFCs flows. An uncertainty budget is presented, resulting in an expanded uncertainty of 2% for the HFC-125 reference mixture and of 2.5% for the HFC-1234yf mixture (95% confidence interval). The final gas, with near-atmospheric concentration (17.11 pmol/mol for HFC-125, 2.14 pmol/mol for HFC-1234yf) is then measured with Medusa-GC/MS technology against standards calibrated on existing reference scales. The assigned values of the dynamic standards are in excellent agreement with measurements vs the existing reference scales, SIO-14 from the Scripps Institution of Oceanography for HFC-125 and Empa-2013 for HFC-1234yf. Moreover, the Medusa-GC/MS measurements show the excellent purity of the SI

  19. The effects of composition on mechanical properties of W-4Re-Hf-C alloys

    Science.gov (United States)

    Witzke, W. R.

    1974-01-01

    Studies were made of the effects of alloy composition on the mechanical behavior of as-worked W-4Re-Hf-C alloys containing up to about 0.8 mol % Hfc. Extracted second-phase particles were analyzed and related to alloy composition and creep strength. While strengthening is attributed to HfC particles, the presence of excess hafnium or carbon (above the calculated amounts for stoichiometric HfC) in swaged W-4Re-Hf-C alloys generally causes a reduction of the high-temperature (1930 C) tensile strength; maximum creep strength is, however, indicated for alloys with a slight (about 0.05 to 0.1 at. %) excess of hafnium. Particle strengthening is reduced by WC in solid solution with HfC for allow compositions with an excess of carbon. The low-temperature ductility of worked W-4Re-Hf-C alloys appears to be far more dependent on the amount of excess C or Hf present than on the HfC particle content in the range studies.

  20. Frequencies of inaudible high-frequency sounds differentially affect brain activity: positive and negative hypersonic effects.

    Directory of Open Access Journals (Sweden)

    Ariko Fukushima

    Full Text Available The hypersonic effect is a phenomenon in which sounds containing significant quantities of non-stationary high-frequency components (HFCs above the human audible range (max. 20 kHz activate the midbrain and diencephalon and evoke various physiological, psychological and behavioral responses. Yet important issues remain unverified, especially the relationship existing between the frequency of HFCs and the emergence of the hypersonic effect. In this study, to investigate the relationship between the hypersonic effect and HFC frequencies, we divided an HFC (above 16 kHz of recorded gamelan music into 12 band components and applied them to subjects along with an audible component (below 16 kHz to observe changes in the alpha2 frequency component (10-13 Hz of spontaneous EEGs measured from centro-parieto-occipital regions (Alpha-2 EEG, which we previously reported as an index of the hypersonic effect. Our results showed reciprocal directional changes in Alpha-2 EEGs depending on the frequency of the HFCs presented with audible low-frequency component (LFC. When an HFC above approximately 32 kHz was applied, Alpha-2 EEG increased significantly compared to when only audible sound was applied (positive hypersonic effect, while, when an HFC below approximately 32 kHz was applied, the Alpha-2 EEG decreased (negative hypersonic effect. These findings suggest that the emergence of the hypersonic effect depends on the frequencies of inaudible HFC.

  1. Investigation into the fractionation of refrigerant blends. Final technical report, March 1994--December 1995

    Energy Technology Data Exchange (ETDEWEB)

    Biancardi, F.R.; Michels, H.; Sienel, T.; Pandy, D.

    1996-01-01

    As a means of complying with current and impending national and international environmental regulations restricting the use and disposal of conventional CFC and HCFC refrigerants which contribute to the global ozone depletion effects, the HVAC industry is vigorously evaluating and testing BFC refrigerant blends. While analyses and system performance tools have shown that BFC refrigerant blends offer certain performance, capacity and operational advantages, there are significant possible service and operational issues that are raised by the use of blends. Many of these issues occur due to the fractionation of the blends. Therefore, the objective of this program is to conduct analyses and experimental tests aimed at understanding these issues, develop approaches or techniques to predict these effects and convey to the industry safe and reliable approaches. As a result, analytical models, verified by laboratory data, have been developed that predict the fractionation effects of HFC refrigerant blends when (1) exposed to selected POE lubricants, (2) during the system charging process from large liquid containers, and (3) during system startup, operation and shutdown within various system components (where two-phase refrigerant exists), and during selected system and component leakage scenarios. Model predictions and experimental results are presented for HFC refrigerant blends containing HFC-32, HFC-134a, and HFC-125 and the data are generalized for various operating conditions and scenarios.

  2. Frequencies of inaudible high-frequency sounds differentially affect brain activity: positive and negative hypersonic effects.

    Science.gov (United States)

    Fukushima, Ariko; Yagi, Reiko; Kawai, Norie; Honda, Manabu; Nishina, Emi; Oohashi, Tsutomu

    2014-01-01

    The hypersonic effect is a phenomenon in which sounds containing significant quantities of non-stationary high-frequency components (HFCs) above the human audible range (max. 20 kHz) activate the midbrain and diencephalon and evoke various physiological, psychological and behavioral responses. Yet important issues remain unverified, especially the relationship existing between the frequency of HFCs and the emergence of the hypersonic effect. In this study, to investigate the relationship between the hypersonic effect and HFC frequencies, we divided an HFC (above 16 kHz) of recorded gamelan music into 12 band components and applied them to subjects along with an audible component (below 16 kHz) to observe changes in the alpha2 frequency component (10-13 Hz) of spontaneous EEGs measured from centro-parieto-occipital regions (Alpha-2 EEG), which we previously reported as an index of the hypersonic effect. Our results showed reciprocal directional changes in Alpha-2 EEGs depending on the frequency of the HFCs presented with audible low-frequency component (LFC). When an HFC above approximately 32 kHz was applied, Alpha-2 EEG increased significantly compared to when only audible sound was applied (positive hypersonic effect), while, when an HFC below approximately 32 kHz was applied, the Alpha-2 EEG decreased (negative hypersonic effect). These findings suggest that the emergence of the hypersonic effect depends on the frequencies of inaudible HFC.

  3. Numerical Simulation for Thermal Shock Resistance of Thermal Protection Materials Considering Different Operating Environments

    Directory of Open Access Journals (Sweden)

    Weiguo Li

    2013-01-01

    Full Text Available Based on the sensitivities of material properties to temperature and the complexity of service environment of thermal protection system on the spacecraft, ultrahigh-temperature ceramics (UHTCs, which are used as thermal protection materials, cannot simply consider thermal shock resistance (TSR of the material its own but need to take the external constraint conditions and the thermal environment into full account. With the thermal shock numerical simulation on hafnium diboride (HfB2, a detailed study of the effects of the different external constraints and thermal environments on the TSR of UHTCs had been made. The influences of different initial temperatures, constraint strengths, and temperature change rates on the TSR of UHTCs are discussed. This study can provide a more intuitively visual understanding of the evolution of the TSR of UHTCs during actual operation conditions.

  4. Structure and thermal cycling stability of a hafnium monocarbide reinforced directionally solidified cobalt-base eutectic alloy

    Science.gov (United States)

    Kim, Y. G.

    1975-01-01

    A nominal composition of Co-15Cr-20Ni-10.5Hf-0.7C was directionally solidified at 0.8 cm/hr growth rate to produce aligned HfC in a cobalt matrix alloy. The aligned HfC fibers were present as rod and plate types. The diameter of the aligned fibers was about 1 micron, with volume fraction in the range of 11 to 15 per cent. The growth direction of the fibers was parallel to the 100 direction. The alloy was subjected to thermal cycling between 425 and 1100 C, using a 2.5 minute cycle. No microstructural degradation of the HfC fibers in the alloy was observed after 2500 cycles.

  5. Compositional effects on mechanical properties of hafnium-carbide-strengthened molybdenum alloys

    Science.gov (United States)

    Witzke, W. R.

    1975-01-01

    The mechanical properties of swaged rod thermomechanically processed from arc melted Mo-2Re-Hf-C alloys containing as much as 0.9-mol% HfC were evaluated. The low-temperature ductilities of these alloys were not influenced by the amount of HfC present but by the amount of Hf in excess of stoichiometry. Maximum ductility occurred at 0.2- to 0.3-at.% excess Hf. At 0.3- to 0.5-mol% HfC, alloy strength varied directly with the Mo content of extracted carbide particles, both decreasing as the amount of excess Hf increased. Additions of 2-at.% Re had little effect on strength or ductility. Tensile and creep strengths of Mo-2Re-0.7Hf-0.5C alloy equaled or exceeded those of other high strength Mo alloys.

  6. Hiperlipidemia familiar combinada: documento de consenso

    Directory of Open Access Journals (Sweden)

    Pedro Mata

    2014-10-01

    Es frecuente la asociación con diabetes mellitus tipo 2, hipertensión arterial y obesidad central. Los pacientes con HFC se consideran de riesgo cardiovascular alto y el objetivo terapéutico es un colesterol-LDL < 100 mg/dl, y < 70 mg/dl en presencia de enfermedad cardiovascular establecida o diabetes mellitus. Los pacientes con HFC requieren tratamiento con estatinas potentes y, a veces, tratamiento combinado. La identificación y el manejo de otros factores de riesgo cardiovascular, como la diabetes y la hipertensión, son fundamentales para reducir la carga de enfermedad cardiovascular. Este documento proporciona recomendaciones para el diagnóstico y el tratamiento integral de los pacientes con HFC especialmente dirigidas a médicos de atención primaria.

  7. Formation of high-carbon abrasion-resistant surface layers when high-energy heating by high-frequency currents

    Science.gov (United States)

    Plotnikova, N. V.; Skeeba, V. Yu; Martyushev, N. V.; Miller, R. A.; Rubtsova, N. S.

    2016-11-01

    The paper shows the possibility of carburization of low-carbon steel surface layers using high-frequency currents. The mathematical modeling of carburization using high-energy heating by high-frequency currents (HEH HFC) has been carried out, the temperature fields formed during the given processing have been calculated, as well as the structural changes in the surface layers have been simulated. The features of the structure formation in the surface layers of low-carbon steel after carburizing via HEH HFC have been determined by optical and scanning microscopy, which is confirmed by the computational models. The rational mode of fusion via HEH HFC has also been determined (power density of the source qs = (1.5 ... 4.0) • 108 W m-2, (the relative travel speed of parts Vp = 5 ... 100 mm / sec), with forming the compressive retained stresses in the surface layer (σRS ≈ -300 ... -400 MPa).

  8. Infrared cross sections and global warming potentials of 10 alternative hydrohalocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Clerbaux, C.; Colin, R. [Universite Libre de Bruzelles, Brussels (Belgium); Simon, P.C. [Institut d`Aeronomie Spatiale de Belgique, Brussels (Belgium)] [and others

    1993-06-20

    Absorption cross sections have been obtained in the infrared atmospheric window, between 600 and 1500 cm{sup {minus}1}, for 10 alternative hydrohalocarbons: HCFC22, HCFC123, HCFC124, HCFC141b, HCFC142b, HCFC225ca, HCFC225cb, HFC125, HFC134a and HFC152a. The measurements were made at three temperatures (287 K, 270 K and 253 K) with a Fourier transform spectrometer operating at 0.03 cm{sup {minus}1} apodized resolution. Integrated cross sections have been introduced into a two-dimensional radiative-chemical-dynamical model in order to calculate the global warming potential (GWP) of each gas. 27 refs., 2 figs., 3 tabs.

  9. Experimental Study on Vapor Pressure of HFC—134a

    Institute of Scientific and Technical Information of China (English)

    Ming-ShanZhu; Yi-DongFu; 等

    1992-01-01

    As part of the study on thermophysical properties of HFC-134a,this paper concerns itself with vapor pressure of HFC-134a in the temperature range of 279.15K to 365.15K,A total of 43 measurement data were measured during the experiment which was conducted on a high precision pVTx test apparatus designed by the authors with slight modifications,Uncertainties of temperature was ±10mK and of pressure was±500Pa,purity of sample was either 99.95wt%,or 99.98wt%,Data resulting from this experiment matched closely with the newest data published internationalyy,Compared to our porposed equation for calculating vapor pressure of HFC-134a,the RMS deviation cfexperimental data was only 0.0531%,showing relatively high precision.

  10. Performance evaluation of R404A and R507A refrigerant mixtures in an experimental double-stage vapour compression plant

    Energy Technology Data Exchange (ETDEWEB)

    Llopis, R.; Cabello, R.; Sanchez, D. [Department of Mechanical Engineering and Construction, Campus de Riu Sec. Jaume I University, E-12071 Castellon (Spain); Torrella, E. [Department of Applied Thermodynamics, Camino de Vera, 14. Polytechnic University of Valencia, E-46022 Valencia (Spain)

    2010-05-15

    As a result of the ban of the CFC fluids in 2000 and the future limitation of HCFC fluids, which manufacture limit is the year 2010, refrigerant producers have been working to develop different mixtures, mainly based on HFC fluids, which emulate the properties of the former refrigerants used in refrigeration plants. At the moment, the HFC-404A and the HFC-507A are the more widely used fluids in Europe as replacement of the CFC-502 in plants operating at low temperatures. This work presents the experimental evaluation, from an energy point of view, of both refrigerants in the same refrigeration plant, which corresponds to a double-stage vapour compression plant driven by a compound compressor. The characterization was made for an evaporating temperature range between -36 and -20 C for a constant condensing temperature of 40 C. (author)

  11. Energy Efficient Commercial Refrigeration with Carbon Dioxide Refrigerant and Scroll Expanders

    Energy Technology Data Exchange (ETDEWEB)

    Dieckmann, John [TIAX LLC, Lexington, MA (United States)

    2013-04-04

    Current supermarket refrigeration systems are built around conventional fluorocarbon refrigerants – HFC-134a and the HFC blends R-507 and R404A, which replaced the CFC refrigerants, R-12 and R-502, respectively, used prior to the Montreal Protocol phase out of ozone depleting substances. While the HFC refrigerants are non-ozone depleting, they are strong greenhouse gases, so there has been continued interest in replacing them, particularly in applications with above average refrigerant leakage. Large supermarket refrigeration systems have proven to be particularly difficult to maintain in a leak-tight condition. Refrigerant charge losses of 15% of total charge per year are the norm, making the global warming impact of refrigerant emissions comparable to that associated with the energy consumption of these systems.

  12. Design and methodology of the NorthStar Study: NT-proBNP stratified follow-up in outpatient heart failure clinics -- a randomized Danish multicenter study

    DEFF Research Database (Denmark)

    Schou, Morten; Gustafsson, Finn; Videbaek, Lars;

    2008-01-01

    BACKGROUND: Randomized clinical trials have shown that newly discharged and symptomatic patients with chronic heart failure (CHF) benefit from follow-up in a specialized heart failure clinic (HFC). Clinical stable and educated patients are usually discharged from the HFC when on optimal therapy....... It is unknown if risk stratification using natriuretic peptides could identify patients who would benefit from longer-term follow-up. Furthermore, data on the use of natriuretic peptides for monitoring of stable patients with CHF are sparse. AIMS: The aims of this study are to test the hypothesis that clinical...... stable, educated, and medical optimized patients with CHF with N-terminal pro-brain natriuretic peptide (NT-proBNP) levels > or = 1,000 pg/mL benefit from long-term follow-up in an HFC and to assess the efficacy of NT-proBNP monitoring. METHODS: A total of 1,250 clinically stable, medically optimized...

  13. Development and characterization of metal-diboride-based composites toughened with ultra-fine SiC particulates

    Science.gov (United States)

    Monteverde, Frédéric; Bellosi, Alida

    2005-05-01

    Two metal-diboride-based ceramics containing up to 15 vol%. ultra-fine α-SiC particulates were developed from commercially available powders. The primary matrix of the composites was ZrB 2 or a mixture of ZrB 2 and HfB 2. With the assistance of 4.5 vol%. ZrN as a sintering aid, both the compositions achieved nearly full density after hot-pressing at 1,900 °C. The microstructure was characterized by fine diboride grains ( ≈3 μm average size) and SiC particles dispersed uniformly. Limited amounts of secondary phases like MO 2 and M(C,N), M=Zr or Zr/Hf, were found. The thermo-mechanical data of both the materials offered a promising combination of properties: about 16 GPa of micro-hardness, 5 MPa√ m of fracture toughness and Young's moduli exceeding 470 GPa. The ZrB 2sbnd SiC composite showed values of strength in air of 635 ± 60 and 175 ± 15 MPa at 25 and 1,500 °C, respectively. Likewise, the (ZrB 2 + HfB 2) sbnd SiC composite exhibited values of strength in air of 590 ± 25 and 190 ± 20 MPa at 25 and 1,500 °C, respectively. The composites also displayed good tolerance of conditions of repeated short exposures, 10 minutes each, at 1,700 °C in stagnant air. In such oxidizing conditions, the resistance to oxidation was provided by the formation of a protective silica-based glass coating, the primary oxidation product of SiC. Such a coating encapsulated the specimen coherently, and provided protection to the faces exposed to the hot atmosphere.

  14. Ozone Depletion by Hydrofluorocarbons

    Science.gov (United States)

    Hurwitz, M.; Fleming, E. L.; Newman, P. A.; Li, F.; Mlawer, E. J.; Cady-Pereira, K. E.; Bailey, R.

    2015-12-01

    Hydrofluorocarbons (HFCs) are second-generation replacements for the chlorofluorocarbons (CFCs), halons and other substances that caused the 'ozone hole'. Atmospheric concentrations of HFCs are projected to increase dramatically in the coming decades. Coupled chemistry-climate simulations forced by these projections show that HFCs will impact the global atmosphere in 2050. As strong radiative forcers, HFCs modulate atmospheric temperature, thereby changing ozone-destroying catalytic cycles and enhancing the stratospheric circulation. These changes lead to a weak depletion of stratospheric ozone. Sensitivity simulations with the NASA Goddard Space Flight Center (GSFC) 2D model show that HFC-125 is the most important contributor to atmospheric change in 2050, as compared with HFC-23, HFC-32, HFC-134a and HFC-143a. Incorporating the interactions between chemistry, radiation and dynamics, for a likely 2050 climate, ozone depletion potentials (ODPs) for HFCs range from 4.3x10-4 to 3.5x10-2; previously HFCs were assumed to have negligible ODPs since these species lack chlorine or bromine atoms. The ozone impacts of HFCs are further investigated with the Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM). The GEOSCCM is a three-dimensional, fully coupled ocean-atmosphere model with interactive stratospheric chemistry. Sensitivity simulations in which CO2, CFC-11 and HCFC-22 are enhanced individually are used as proxies for the atmospheric response to the HFC concentrations expected by the mid-21st century. Sensitivity simulations provide quantitative estimates of the impacts of these greenhouse gases on global total ozone, and can be used to assess their effects on the recovery of Antarctic ozone.

  15. 气相色谱-质谱联用法在线观测大气中的氢氟碳化物和全氟化碳%In-situ measurement of atmospheric hydrofluorocarbon and perfluorocarbons using a custom-made GC-MS system

    Institute of Scientific and Technical Information of China (English)

    姚波; 周凌晞; 李培昌; 许林

    2012-01-01

    利用组装的气相色谱-质谱联用系统(GC-MS)同时测定大气中6种氢氟碳化物(HFCs)和4种全氟化碳(PFCs),空气样品采样的时间分辨率120 min,精度范围0.15%—3.11%,准确度范围-1.52%—0.63%.对2011年2月在北京上甸子站的实验观测结果进行分析,获得HFC-23、HFC-32、HFC-134a、HFC-143a、HFC-125、HFC-152a、CF4、PFC-116、PFC-218、PFC-318的本底和非本底浓度,表明该系统适用于大气中HFCs和PFCs浓度在线观测.%A custom-made GC-MS system was designed for in-situ measurement of trace atmospheric hydrofluorocarbons(HFCs) and perfluorocarbons(PFCs).The time resolution of the air samples is 120 min.The precision and accuracy ranges are 0.15%—3.11% and-1.52%—0.63%,respectively.The field measurement results during 2011-02-01—2011-02-28 at the Shangdianzi background station show that the system is able to capture both the background and pollution signals and can be used for in-situ background atmospheric measurements of HFCs and PFCs.

  16. Opinion research with end-users and insurance providers on hydrogen and fuel cell technologies

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-09-18

    The hydrogen and fuel cell (HFC) technologies industry is an emerging market with several barriers to overcome. This paper provided details of a research project undertaken to better understand the needs of hydrogen end-users and suppliers with regard to insurance for their projects. A total of 14 interviews were conducted with end-users and insurance industry representatives. Results indicated that HFC industry respondents did not have enough knowledge or experience of the insurance industry to answer the questions asked of them, in any detail or at all. Insurance industry respondents were aware of the HFC industry's lack of understanding of the insurance industry. It was noted that both groups wish to resolve communication gaps between the 2 industries, and that the development of a mechanism for appropriate communications may resolve misunderstandings. It was suggested that the HFC industry needs to develop a general knowledge of insurance issues as they relate to their industry and a comprehensive understanding of the insurance industry's procedural needs. The HFC industry must also work to educate insurance providers about hydrogen and its safety record. It was suggested that the Canadian Transportation Fuel Cell Alliance (CTFCA) should take a role in educating the insurance industry about hydrogen. It was concluded that despite the lack of understanding and knowledge on the part of the HFC respondents, the study was useful in identifying the nature and depth of the problem, and had validated the input received from the insurance industry respondents. An appendix of study materials was included.

  17. Use of coffee pulp as feed ingredient for tilapia culture

    NARCIS (Netherlands)

    Ulloa Rojas, J.B.

    2002-01-01

    This research focused on the feasibility of using coffee pulp (CoP) in diets for tilapia ( Oreochromis aureus ). First, a literature survey analyzed the limitations of CoP as an animal foodstuff (several antinutritional factors: ANF's, and high fibre contents),

  18. Use of coffee pulp as feed ingredient for tilapia culture

    NARCIS (Netherlands)

    Ulloa Rojas, J.B.

    2002-01-01

    This research focused on the feasibility of using coffee pulp (CoP) in diets for tilapia ( Oreochromis aureus ). First, a literature survey analyzed the limitations of CoP as an animal foodstuff (several antinutritional factors: ANF's, and high fibre contents), different ways to upgrade the CoP nutr

  19. The Constraints on Strategy of an Organizational Structure

    DEFF Research Database (Denmark)

    Eriksen, Bo

    2007-01-01

     Artiklen diskuterer relationen mellem organisationens struktur og dens evne til at formulere og realisere sine strategier. Hovedargumentet er skelner mellem exploration og exploitation strategier og det anføres at der er en indbygget konflikt mellem disse. Fleksible (ambidextrous) organisationer...

  20. Antinutritional effects of legume seeds in piglets, rats and chickens.

    NARCIS (Netherlands)

    Huisman, J.

    1990-01-01

    There is a growing interest in Europe to be self-supporting with regard to the protein supply for animal diets. Peas and beans growing well under European climatic conditions could provide alternatives to soya. However, these legume seeds contain the same classes of antinutritional factors (ANFs) as

  1. 75 FR 6421 - Self-Regulatory Organizations; International Securities Exchange, LLC; Notice of Filing and...

    Science.gov (United States)

    2010-02-09

    ... Applied Materials Inc. AMR AMR Corp. ANF Abercrombie & Fitch Co. APC Anadarko Petroleum Corp. ATVI... Corp. OXY Occidental Petroleum Corp. PARD Poniard Pharmaceuticals Inc. PEP PepsiCo Inc/NC. PM Philip..., remove impediments to and perfect the mechanisms of a free and open market and a national market...

  2. 75 FR 6424 - Self-Regulatory Organizations; NYSE Amex LLC; Notice of Filing and Immediate Effectiveness of...

    Science.gov (United States)

    2010-02-09

    .... 166 ANF Abercrombie & 187 MMM 3M Co. Fitch Co. 172 APC Anadarko Petroleum 140 MU Micron Technology... Occidental Petroleum Corp. 190 BCRX BioCryst 158 PARD Poniard Pharmaceuticals Pharmaceuticals Inc. Inc. 218... principles of trade, remove impediments to and perfect the mechanisms of a free and open market and...

  3. Development of a voltage-dependent current noise algorithm for conductance-based stochastic modelling of auditory nerve fibres.

    Science.gov (United States)

    Badenhorst, Werner; Hanekom, Tania; Hanekom, Johan J

    2016-12-01

    This study presents the development of an alternative noise current term and novel voltage-dependent current noise algorithm for conductance-based stochastic auditory nerve fibre (ANF) models. ANFs are known to have significant variance in threshold stimulus which affects temporal characteristics such as latency. This variance is primarily caused by the stochastic behaviour or microscopic fluctuations of the node of Ranvier's voltage-dependent sodium channels of which the intensity is a function of membrane voltage. Though easy to implement and low in computational cost, existing current noise models have two deficiencies: it is independent of membrane voltage, and it is unable to inherently determine the noise intensity required to produce in vivo measured discharge probability functions. The proposed algorithm overcomes these deficiencies while maintaining its low computational cost and ease of implementation compared to other conductance and Markovian-based stochastic models. The algorithm is applied to a Hodgkin-Huxley-based compartmental cat ANF model and validated via comparison of the threshold probability and latency distributions to measured cat ANF data. Simulation results show the algorithm's adherence to in vivo stochastic fibre characteristics such as an exponential relationship between the membrane noise and transmembrane voltage, a negative linear relationship between the log of the relative spread of the discharge probability and the log of the fibre diameter and a decrease in latency with an increase in stimulus intensity.

  4. Einflüsse auf Husserl

    NARCIS (Netherlands)

    Ierna, Carlo; Luft, Sebastian; Wehrle, Maren

    2017-01-01

    Das vorliegende Kapitel setzt sich zum Ziel, die wichtigsten Einflüsse auf Edmund Husserls vor-transzendentale Philosophie darzustellen. Äußere Einflüsse spielen besonders in den Anfängen von Husserls Philosophie eine Rolle, in der späteren Weiterentwicklung der Phänomenologie zu einer

  5. Effects of Electrode Position on Spatiotemporal Auditory Nerve Fiber Responses: A 3D Computational Model Study

    Directory of Open Access Journals (Sweden)

    Soojin Kang

    2015-01-01

    Full Text Available A cochlear implant (CI is an auditory prosthesis that enables hearing by providing electrical stimuli through an electrode array. It has been previously established that the electrode position can influence CI performance. Thus, electrode position should be considered in order to achieve better CI results. This paper describes how the electrode position influences the auditory nerve fiber (ANF response to either a single pulse or low- (250 pulses/s and high-rate (5,000 pulses/s pulse-trains using a computational model. The field potential in the cochlea was calculated using a three-dimensional finite-element model, and the ANF response was simulated using a biophysical ANF model. The effects were evaluated in terms of the dynamic range, stochasticity, and spike excitation pattern. The relative spread, threshold, jitter, and initiated node were analyzed for single-pulse response; and the dynamic range, threshold, initiated node, and interspike interval were analyzed for pulse-train stimuli responses. Electrode position was found to significantly affect the spatiotemporal pattern of the ANF response, and this effect was significantly dependent on the stimulus rate. We believe that these modeling results can provide guidance regarding perimodiolar and lateral insertion of CIs in clinical settings and help understand CI performance.

  6. Determination of the moisture content in the fluoride oxide fluxes of electroslag remelting

    Science.gov (United States)

    Vdovin, K. N.; Feoktistov, N. A.; Pivovarova, K. G.; Deryabin, D. A.

    2016-12-01

    ANF-32 flux has been studied with regard to the moisture content both after storage and upon operation. A simple and reliable procedure for the determination of the moisture content in ESR fluxes is proposed, and recommendations are given on monitoring the moisture content in calcined fluxes. The main sources of crystallization water of hydration are hydrogen sources.

  7. Hepatic-intestinal disposal of endogenous human alpha atrial natriuretic factor99-126 in patients with cirrhosis

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik; Bendtsen, Flemming; Schütten, H J

    1990-01-01

    Hepatic-intestinal disposal of endogenous human alpha atrial natriuretic factor99-126 (ANF) was assessed in 13 patients with cirrhosis (six Child-Turcotte class A, five class B, and two class C) and eight control subjects. The Fick principle was applied during hepatic vein catheterization. Arterial...

  8. Cochlear Synaptopathy and Noise-Induced Hidden Hearing Loss

    Directory of Open Access Journals (Sweden)

    Lijuan Shi

    2016-01-01

    Full Text Available Recent studies on animal models have shown that noise exposure that does not lead to permanent threshold shift (PTS can cause considerable damage around the synapses between inner hair cells (IHCs and type-I afferent auditory nerve fibers (ANFs. Disruption of these synapses not only disables the innervated ANFs but also results in the slow degeneration of spiral ganglion neurons if the synapses are not reestablished. Such a loss of ANFs should result in signal coding deficits, which are exacerbated by the bias of the damage toward synapses connecting low-spontaneous-rate (SR ANFs, which are known to be vital for signal coding in noisy background. As there is no PTS, these functional deficits cannot be detected using routine audiological evaluations and may be unknown to subjects who have them. Such functional deficits in hearing without changes in sensitivity are generally called “noise-induced hidden hearing loss (NIHHL.” Here, we provide a brief review to address several critical issues related to NIHHL: (1 the mechanism of noise induced synaptic damage, (2 reversibility of the synaptic damage, (3 the functional deficits as the nature of NIHHL in animal studies, (4 evidence of NIHHL in human subjects, and (5 peripheral and central contribution of NIHHL.

  9. Coding deficits in noise-induced hidden hearing loss may stem from incomplete repair of ribbon synapses in the cochlea

    Directory of Open Access Journals (Sweden)

    Lijuan eShi

    2016-05-01

    Full Text Available Recent evidence has shown that noise-induced damage to the synapse between inner hair cells (IHCs and type I afferent auditory nerve fibers (ANFs may occur in the absence of permanent threshold shift (PTS, and that synapses connecting IHCs with low spontaneous rate (SR ANFs are disproportionately affected. Due to the functional importance of low-SR ANF units for temporal processing and signal coding in noisy backgrounds, deficits in cochlear coding associated with noise-induced damage may result in significant difficulties with temporal processing and hearing in noise (i.e., hidden hearing loss. However, significant noise-induced coding deficits have not been reported at the single unit level following the loss of low-SR units. We have found evidence to suggest that some aspects of neural coding are not significantly changed with the initial loss of low-SR ANFs, and that further coding deficits arise in association with the subsequent reestablishment of the synapses. This suggests that synaptopathy in hidden hearing loss may be the result of insufficient repair of disrupted synapses, and not simply due to the loss of low-SR units. These coding deficits include decreases in driven spike rate for intensity coding as well as several aspects of temporal coding: spike latency, peak-to-sustained spike ratio and the recovery of spike rate as a function of click-interval.

  10. Leide Heinrich Gösekeni sõnavaramust / Valve-Liivi Kingisepp

    Index Scriptorium Estoniae

    Kingisepp, Valve-Liivi, 1935-

    2009-01-01

    Analüüsitakse Heinrich Gösekeni käsiraamatu "Manuductio ad Linguam Oesthonicam, Anführung zur Öhstnischen Sprache" (1660) saksa-eesti sõnastikku, võrreldes sealseid leide teiste eesti varasemate ja hilisemate sõnastikega

  11. Dispersions of Aramid Nanofibers: A New Nanoscale Building Block

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ming; Cao, Keqin; Sui, Lang; Qi, Ying; Zhu, Jian; Waas, Anthony; Arruda, Ellen; Kieffer, John; Thouless, M. D.; Kotov, Nicholas A.

    2011-09-27

    Stable dispersions of nanofibers are virtually unknown for synthetic polymers. They can complement analogous dispersions of inorganic components, such as nanoparticles, nanowires, nanosheets, etc. as a fundamental component of a toolset for design of nanostructures and metamaterials via numerous solvent-based processing methods. As such, strong flexible polymeric nanofibers are very desirable for the effective utilization within composites of nanoscale inorganic components such as nanowires, carbon nanotubes, graphene, and others. Here stable dispersions of uniform high-aspect-ratio aramid nanofibers (ANFs) with diameters between 3 and 30 nm and up to 10 μm in length were successfully obtained. Unlike the traditional approaches based on polymerization of monomers, they are made by controlled dissolution of standard macroscale form of the aramid polymer, that is, well-known Kevlar threads, and revealed distinct morphological features similar to carbon nanotubes. ANFs are successfully processed into films using layer-by-layer (LBL) assembly as one of the potential methods of preparation of composites from ANFs. The resultant films are transparent and highly temperature resilient. They also display enhanced mechanical characteristics making ANF films highly desirable as protective coatings, ultrastrong membranes, as well as building blocks of other high performance materials in place of or in combination with carbon nanotubes.

  12. 75 FR 6239 - Self-Regulatory Organizations; The NASDAQ Stock Market LLC; Notice of Filing and Immediate...

    Science.gov (United States)

    2010-02-08

    ... months ending December 31, 2009. Nat'l ranking Symbol Company name Nat'l ranking Symbol Company name 131.... Inc 117 AMR AMR Corp 217 MET MetLife Inc. 166 ANF Abercrombie & 187 MMM 3M Co. Fitch Co 172 APC...

  13. 75 FR 6233 - Self-Regulatory Organizations; NASDAQ OMX PHLX, Inc.; Notice of Filing and Immediate...

    Science.gov (United States)

    2010-02-08

    .... Nat'l ranking Symbol Company name Nat'l ranking Symbol Company name 131 ABT Abbott 192 LEAP Leap... MetLife Inc. 166 ANF Abercrombie & Fitch 187 MMM 3M Co. Co. 172 APC Anadarko Petroleum 140 MU Micron...

  14. Wiener kernels of chinchilla auditory-nerve fibers : Verification using responses to tones, clicks, and noise and comparison with basilar-membrane vibrations

    NARCIS (Netherlands)

    Temchin, AN; Recio-Spinoso, A; van Dijk, P; Ruggero, MA

    2005-01-01

    Responses to tones, clicks, and noise were recorded from chinchilla auditory-nerve fibers (ANFs). The responses to noise were analyzed by computing the zeroth-, first-, and second-order Wiener kernels (h(0), h(1), and h(2)). The h(1) s correctly predicted the frequency tuning and phases of responses

  15. Principal dynamic mode analysis of neural mass model for the identification of epileptic states.

    Science.gov (United States)

    Cao, Yuzhen; Jin, Liu; Su, Fei; Wang, Jiang; Deng, Bin

    2016-11-01

    The detection of epileptic seizures in Electroencephalography (EEG) signals is significant for the diagnosis and treatment of epilepsy. In this paper, in order to obtain characteristics of various epileptiform EEGs that may differentiate different states of epilepsy, the concept of Principal Dynamic Modes (PDMs) was incorporated to an autoregressive model framework. First, the neural mass model was used to simulate the required intracerebral EEG signals of various epileptiform activities. Then, the PDMs estimated from the nonlinear autoregressive Volterra models, as well as the corresponding Associated Nonlinear Functions (ANFs), were used for the modeling of epileptic EEGs. The efficient PDM modeling approach provided physiological interpretation of the system. Results revealed that the ANFs of the 1st and 2nd PDMs for the auto-regressive input exhibited evident differences among different states of epilepsy, where the ANFs of the sustained spikes' activity encountered at seizure onset or during a seizure were the most differentiable from that of the normal state. Therefore, the ANFs may be characteristics for the classification of normal and seizure states in the clinical detection of seizures and thus provide assistance for the diagnosis of epilepsy.

  16. Modelling of heat treatment of soy

    NARCIS (Netherlands)

    Hout, van den R.

    1997-01-01


    Soybeans are used as raw material for human nutrition and animal feed because of their high nutritional value. Consumption of raw beans has negative effects on the growth and health of human beings and animals. These effects are caused by antinutritional. factors (ANFs). Trypsin

  17. Modelling of heat treatment of soy

    NARCIS (Netherlands)

    Hout, van den R.

    1997-01-01


    Soybeans are used as raw material for human nutrition and animal feed because of their high nutritional value. Consumption of raw beans has negative effects on the growth and health of human beings and animals. These effects are caused by antinutritional. factors (ANFs). Trypsin inhibitor

  18. 925-IJBCS-Article-Dr Deji Fasuyi

    African Journals Online (AJOL)

    DR GATSING

    Available online at http://ajol.info/index.php/ijbcs. Int. J. Biol. Chem. Sci. ... nutritional evaluation for TDLM as a potential non-ruminant feed ingredient. ANFs have been ..... conventional food/feed materials. With its rich ... under-utilized crop seeds in Nigeria. Food Chem. ... beans (Vicia faba L.) on the digestion of amino acids ...

  19. Stålkonstruktioner efter DS/EN 1993

    DEFF Research Database (Denmark)

    Jensen, Bjarne Christian; Bonnerup, Bent; Plum, Carsten Munk

    eksempler kan bruges som inspiration i det daglige arbejde. Bogen giver en grundig indføring i beregning af stålkonstruktioner efter DS/EN 1993, inkl. de danske annekser. Desuden er der flere steder anført almindeligt accepterede tilnærmede beregningsmetoder, som forfatterne har vurderet nyttige for de...

  20. Evaluation of growth, nutrient retention, health, and resistance to bacterial challenge in sunshine bass fed diets with new varieties of non-genetically modified soybeans

    Science.gov (United States)

    We evaluated the effects of meals made from new strains of soybeans with high protein and reduced anti-nutritional factors (ANFs) on hybrid striped bass ("Sunshine bass", Morone chrysops x M. saxatilis) nutrient availability, growth rates, nutrient retention, gut histology, non-specific immune respo...

  1. Pea proteins for piglets: effects on digestive processes.

    NARCIS (Netherlands)

    le Guen, M.P.

    1993-01-01

    White-flowered pea ( Pisum sativum ) contains 20 to 25% crude protein (Nx6.25). The pea proteins consist in globulins (60%) and albumins (25%). Because the pea albumin proteins have biological activities due to their metabolic roles in the seed, some of them are called antinutritional factors (ANFs)

  2. Kaupmehekirik Läänemereruumis / Paul Johansen ; tõlk. Jüri Kivimäe

    Index Scriptorium Estoniae

    Johansen, Paul

    2005-01-01

    Kaupmehekirik kui mõiste tähendas, et see kirik ei allunud piiskopile, vaid oli kaupmeeskonna käsutuses. Ilm.: Studien zu den Anfängen des europäischen Städtwesens. Lindau-Konstanze, 1958, lk. 499-525

  3. Hepatic-intestinal disposal of endogenous human alpha atrial natriuretic factor99-126 in patients with cirrhosis

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Bendtsen, F; Schütten, H J

    1990-01-01

    Hepatic-intestinal disposal of endogenous human alpha atrial natriuretic factor99-126 (ANF) was assessed in 13 patients with cirrhosis (six Child-Turcotte class A, five class B, and two class C) and eight control subjects. The Fick principle was applied during hepatic vein catheterization. Arterial...

  4. Optimization of soybean processing into kinema, a Bacillus-fermented alkaline food, with respect to a minimum level of antinutrients

    NARCIS (Netherlands)

    Sharma, A.; Kumari, S.; Wongputtisin, P.; Nout, M.J.R.; Sarkar, P.K.

    2015-01-01

    Aims Optimization of traditional processing of soybeans using response surface methodology (RSM) to achieve a minimum level of antinutritional factors (ANFs) in kinema. Methods and Results Central composite rotatable designs were used to optimize the processing stages of kinema preparation. In each

  5. Biological treatments affect the chemical composition of coffee pulp

    NARCIS (Netherlands)

    Ulloa Rojas, J.B.; Verreth, J.A.J.; Amato, S.; Huisman, E.A.

    2003-01-01

    Biological treatments were applied to fresh coffee pulp (CoP) to improve its nutritive value for monogastric animals by reducing its content of cellulose and antinutritional factors (ANFs) such as total phenols, tannins and caffeine. Treatments were: (1) ensiling with 0, 50 and 100 g kg¿1 molasses f

  6. Principal dynamic mode analysis of neural mass model for the identification of epileptic states

    Science.gov (United States)

    Cao, Yuzhen; Jin, Liu; Su, Fei; Wang, Jiang; Deng, Bin

    2016-11-01

    The detection of epileptic seizures in Electroencephalography (EEG) signals is significant for the diagnosis and treatment of epilepsy. In this paper, in order to obtain characteristics of various epileptiform EEGs that may differentiate different states of epilepsy, the concept of Principal Dynamic Modes (PDMs) was incorporated to an autoregressive model framework. First, the neural mass model was used to simulate the required intracerebral EEG signals of various epileptiform activities. Then, the PDMs estimated from the nonlinear autoregressive Volterra models, as well as the corresponding Associated Nonlinear Functions (ANFs), were used for the modeling of epileptic EEGs. The efficient PDM modeling approach provided physiological interpretation of the system. Results revealed that the ANFs of the 1st and 2nd PDMs for the auto-regressive input exhibited evident differences among different states of epilepsy, where the ANFs of the sustained spikes' activity encountered at seizure onset or during a seizure were the most differentiable from that of the normal state. Therefore, the ANFs may be characteristics for the classification of normal and seizure states in the clinical detection of seizures and thus provide assistance for the diagnosis of epilepsy.

  7. The effects of CYP1A inhibition on alkyl-phenanthrene metabolism and embryotoxicity in marine medaka (Oryzias melastigma).

    Science.gov (United States)

    Mu, Jingli; Jin, Fei; Wang, Juying; Wang, Ying; Cong, Yi

    2016-06-01

    Alkylated polycyclic aromatic hydrocarbons (alkyl-PAHs) are the predominant form of PAHs in crude oils, of which, 3-5 ring alkyl-PAH may cause dioxin-like toxicity to early life stages of fish. Retene (7-isopropyl-1-methylphenanthrene), a typical alkyl-phenanthrene compound, can be more toxic than phenanthrene, and the mechanism of retene toxicity is likely related to its rapid biotransformation by cytochrome P450 (CYP) enzymes to metabolites with a wide array of structures and potential toxicities. Here, we investigated how α-naphthoflavone (ANF), a cytochrome P450 1A (CYP1A) inhibitor, affected the embryotoxicity of retene and the role that CYP1A inhibition may play in the interactions. Marine medaka (Oryzias melastigma) embryos were exposed, separately or together, to 200 μg/L retene with 0, 5, 10, 100, and 200 μg/L ANF for 14 days. The results showed that ANF significantly inhibited the induction of CYP1A activity by retene; however, ANF interacted with retene to induce significant developmental toxicity and genotoxicity at 10, 100, and 200 μg/L (p embryotoxicity to marine medaka. Therefore, elevated toxicity of alkyl-phenanthrene under CYP1A inhibitor suggested that the ecotoxicity of PAHs in coastal water may have underestimated the threat of PAHs to fish or ecosystem.

  8. Kaupmehekirik Läänemereruumis / Paul Johansen ; tõlk. Jüri Kivimäe

    Index Scriptorium Estoniae

    Johansen, Paul

    2005-01-01

    Kaupmehekirik kui mõiste tähendas, et see kirik ei allunud piiskopile, vaid oli kaupmeeskonna käsutuses. Ilm.: Studien zu den Anfängen des europäischen Städtwesens. Lindau-Konstanze, 1958, lk. 499-525

  9. Non azeotrope mixing refrigerating fluids condensation outside of an horizontal tubes stack; Condensation de melanges non azeotropes de fluides frigorigenes a l'exterieur d'un faisceau de tubes horizontaux

    Energy Technology Data Exchange (ETDEWEB)

    Signe, J.Ch.

    1999-04-16

    The development of non-azeotrope mixing, as regular refrigerating fluids substitute, calls in question the experience for the design of refrigerating and cooling machinery. Studies to better understand these fluids behaviour are necessary. The aim of this thesis is the knowledge enlargement on the pure fluids and non azeotrope mixing condensation, outside of a tubes stack, and to simulate the heat transfers. The tubes stack is a condenser, type TEMA X often used in refrigerating machinery. The binary mixing HFC 134a-HFC23, allows a large sliding scale. (A.L.B.)

  10. Extended heart failure clinic follow-up in low-risk patients

    DEFF Research Database (Denmark)

    Schou, Morten; Gustafsson, Finn; Videbaek, Lars

    2013-01-01

    BackgroundOutpatient follow-up in specialized heart failure clinics (HFCs) is recommended by current guidelines and implemented in most European countries, but the optimal duration of HFC programmes has not been established. Nor is it known whether all or only high-risk patients, e.g. identified ......-up in a specialized HFC in a publicly funded universal access healthcare system. Heart failure patients on optimal medical therapy with mild or moderate symptoms are safely managed by their personal GP.Trial Registration: www.Centerwatch.com: 173491 (NorthStar)....

  11. High Strength Carbide-Based Fibrous Monolith Materials for Solid Rocket Nozzles

    Science.gov (United States)

    2008-02-19

    3950°C and 3928°C, respectively. Compared to refractory metal candidates such as Rhenium (W) and Tungsten (W), these carbides offer significant...45HfC-10VC at 1538 W/cm² in the LHMEL Facility laser Sample gone within ~3 seconds, ablated and blew away; carbon foam backing remained intact for...Response of 45TaC-45HfC-10VC at 1529 W/cm² in the LHMEL Facility laser Sample gone within 6 seconds, ablated and blew away; carbon foam backing

  12. Extended heart failure clinic follow-up in low-risk patients

    DEFF Research Database (Denmark)

    Schou, Morten; Gustafsson, Finn; Videbaek, Lars

    2013-01-01

    BackgroundOutpatient follow-up in specialized heart failure clinics (HFCs) is recommended by current guidelines and implemented in most European countries, but the optimal duration of HFC programmes has not been established. Nor is it known whether all or only high-risk patients, e.g. identified ......-up in a specialized HFC in a publicly funded universal access healthcare system. Heart failure patients on optimal medical therapy with mild or moderate symptoms are safely managed by their personal GP.Trial Registration: www.Centerwatch.com: 173491 (NorthStar)....

  13. New use of ammonia in heat pumps; Nouvelle utilisation de l`ammoniac en pompe a chaleur

    Energy Technology Data Exchange (ETDEWEB)

    Hivet, B.; Ducruet, C. [Electricite de France, 77 - Moret sur Loing (France). Direction des Etudes et Recherches

    1996-12-31

    According to simple thermodynamic criteria and to pollution regulations, ammonia and HFC 134a are the only refrigerating fluids that can be used in heat pumps. Ammonia is particularly performing at high condensation temperatures. However, its use has become possible thanks to the use of industrial refrigerating compressors with a maximum operation pressure of 40 bars. Test results confirm the interesting thermal performances of this fluid. A comparison with the HFC 134a refrigerant indicates that ammonia leads to equal or better coefficients of performance for higher volume powers. Two applications taken in the agriculture and food industries are presented. (J.S.)

  14. Hiperlipidemia familiar combinada: documento de consenso

    OpenAIRE

    Pedro Mata; Rodrigo Alonso; Antonio Ruíz-Garcia; Jose L. Díaz-Díaz; Noemí González; Teresa Gijón-Conde; Ceferino Martínez-Faedo; Ignacio Morón; Ezequiel Arranz; Rocío Aguado; Rosa Argueso; Leopoldo Perez de Isla

    2014-01-01

    La hiperlipidemia familiar combinada (HFC) es un trastorno muy frecuente asociado a enfermedad coronaria prematura. Se transmite de forma autosómica dominante, aunque no existe un gen único asociado al trastorno. El diagnóstico se realiza mediante criterios clínicos, y son importantes la variabilidad del fenotipo lipídico y la historia familiar de hiperlipidemia. Es frecuente la asociación con diabetes mellitus tipo 2, hipertensión arterial y obesidad central. Los pacientes con HFC se cons...

  15. Avaliação do comportamento experimental do sistema de refrigeração de um tunel de congelamento com R-502 e R-408A

    OpenAIRE

    Flavio Vasconcelos da Silva

    1998-01-01

    Resumo: Com a implantação das restrições adotadas a partir do Protocolo de Montreal, torna-se importante a avaliação experimental do desempenho de novos fluidos refrigerantes. O R-502 (mistura azeotrópica HCFC-22 / CFC-115; 48,8% / 51,2%) é extensivamente utilizado como fluido refrigerante em equipamentos de refrigeração a baixas temperaturas. Já o R-408A (mistura quase azeotrópica composta de HCFC-22 / HFC-125 / HFC-143a; 47% / 7% / 46%) pode apresentar vantagens como substituto do R-502 em ...

  16. Differential modulation of transforming growth factor-betas and cyclooxygenases in the platelet lysates of male F344 rats by dietary lipids and piroxicam.

    Science.gov (United States)

    Raju, Jayadev; Bird, Ranjana P

    2002-02-01

    Platelets are implicated in the pathogenesis of various chronic diseases including cancer. The main objective of the present study was to determine if dietary fish oil and piroxicam, known modulators of colon tumorigenesis, effect transforming growth factor (TGF)-betas and cyclooxygenase (COX) isozymes in the platelets of colon tumor-bearing male F344 rats. TGF-betas and COXs are important in the development of chronic illnesses including colon cancer. Animals harboring preneoplastic colonic lesions were randomly allocated to a low fat diet (5% by weight--low corn oil, LFC) and three high fat diets (23% by weight--high corn oil, HFC; high corn oil containing 150-ppm piroxicam, HFC+P; and high fish oil, HFF) for 16 weeks. TGF-beta1, TGF-beta2, COX-1 and COX-2 protein levels were assessed in the platelets by Western blot analysis. Active TGF-beta1 (12.5 kDa) level was significantly lower in the platelets of the HFC+P group (p level was significantly lower in the platelets of the HFF group (p protein in the platelets. However a 29-kDa protein, potentially a precursor of TGF-beta2, was detected in the platelets of all the groups and was significantly lower in the HFC+P and HFF groups than in LFC and HFC (p level was significantly lower in the HFF group than the other three groups (p protein was detected in the platelets of all diet groups. Piroxicam in the presence of high corn oil (HFC+P) significantly lowered the level of COX-2 (p level. These findings conclusively show that LFC and HFC differ from HFF and HFC+P, and piroxicam differs from fish oil, in regulating the levels of TGF-betas and COX in the platelets. This supports the conjecture that the levels of bioactive constituents of the platelets are profoundly modulated by dietary lipids, which in turn could influence the pathogenesis of chronic illnesses.

  17. Alteraciones metabólicas de la Hiperlipemia Familiar Combinada y su asociación con la obesidad abdominal y la inflamación de bajo grado

    OpenAIRE

    Díaz Ruiz, María

    2015-01-01

    La HFC es un síndrome dislipémico descrito por Goldstein et al en 1973 identificado al estudiar a jóvenes supervivientes de un infarto agudo de miocardio y a sus familias. Observaron en ellos diferentes fenotipos metabólicos y lipoproteicos, con presencia de elevaciones de los niveles de colesterol total y/o triglicéridos, junto con elevación de lipoproteínas VLDL, de LDL, o de ambas lipoproteínas. La HFC presenta el desarrollo de arteriosclerosis como la manifestación clínica responsable de...

  18. Dietary fiber prevents obesity-related liver lipotoxicity by modulating sterol-regulatory element binding protein pathway in C57BL/6J mice fed a high-fat/cholesterol diet

    OpenAIRE

    2015-01-01

    Adequate intake of dietary fibers has proven metabolic and cardiovascular benefits, molecular mechanisms remain still limited. This study was aimed to investigate the effects of cereal dietary fiber on obesity-related liver lipotoxicity in C57BL/6J mice fed a high-fat/cholesterol (HFC) diet and underlying mechanism. Forty-eight adult male C57BL/6J mice were randomly given a reference chow diet, or a high fat/choleserol (HFC) diet supplemented with or without oat fiber or wheat bran fiber for ...

  19. Mass Potentials Recorded at the Round Window Enable the Detection of Low Spontaneous Rate Fibers in Gerbil Auditory Nerve

    Science.gov (United States)

    Batrel, Charlène; Huet, Antoine; Hasselmann, Florian; Wang, Jing; Desmadryl, Gilles; Nouvian, Régis

    2017-01-01

    Auditory nerve fibers (ANFs) transmit acoustic information from the sensory hair cells to the cochlear nuclei. In experimental and clinical audiology, probing the whole ANF population remains a difficult task, as the ANFs differ greatly in their threshold and onset response to sound. Thus, low spontaneous rate (SR) fibers, which have rather higher thresholds, delay and larger jitter in their first spike latency are not detectable in the far-field compound action potential of the auditory nerve. Here, we developed a new protocol of acoustic stimulation together with electrophysiological signal processing to track the steady state activity of ANFs. Mass potentials at the round window were recorded in response to repetitive 300-ms bursts of 1/3 octave band noise centered on a frequency probe. Analysis was assessed during the last 200-ms of the response to capture the steady-state response of ANFs. To eliminate the microphonic component reflecting the sensory cells activity, repetitive pairs of sounds of opposite polarities were used. The spectral analysis was calculated on the average of two consecutive responses, and the neural gain was calculated by dividing point-by-point the spectrum to sound over unstimulated condition. In response to low-sound-level stimulation, neural gain predominated in the low-frequency cochlear regions, while a second component of responses centered on higher cochlear frequency regions appeared beyond 30 dB SPL. At 60 dB SPL, neural gain showed a bimodal shape, with a notch near 5.6 kHz. In addition to correlate with the functional mapping of ANFs along the tonotopic axis, the deletion of low-SR fibers leads to a reduction in the high-frequency response, where the low-SR fibers are preferentially located. Thus, mass potentials at the round window may provide a useful tool to probe the SR-based distribution of ANFs in humans and in other species in which direct single-unit recordings are difficult to achieve or not feasible. PMID:28085968

  20. Dietary fiber prevents obesity-related liver lipotoxicity by modulating sterol-regulatory element binding protein pathway in C57BL/6J mice fed a high-fat/cholesterol diet.

    Science.gov (United States)

    Han, Shufen; Jiao, Jun; Zhang, Wei; Xu, Jiaying; Wan, Zhongxiao; Zhang, Weiguo; Gao, Xiaoran; Qin, Liqiang

    2015-10-29

    Adequate intake of dietary fibers has proven metabolic and cardiovascular benefits, molecular mechanisms remain still limited. This study was aimed to investigate the effects of cereal dietary fiber on obesity-related liver lipotoxicity in C57BL/6J mice fed a high-fat/cholesterol (HFC) diet and underlying mechanism. Forty-eight adult male C57BL/6J mice were randomly given a reference chow diet, or a high fat/cholesterol (HFC) diet supplemented with or without oat fiber or wheat bran fiber for 24 weeks. Our results showed mice fed oat or wheat bran fiber exhibited lower weight gain, lipid profiles and insulin resistance, compared with HFC diet. The two cereal dietary fibers potently decreased protein expressions of sterol regulatory element binding protein-1 and key factors involved in lipogenesis, including fatty acid synthase and acetyl-CoA carboxylase in target tissues. At molecular level, the two cereal dietary fibers augmented protein expressions of peroxisome proliferator-activated receptor alpha and gamma, liver X receptor alpha, and ATP-binding cassette transporter A1 in target tissues. Our findings indicated that cereal dietary fiber supplementation abrogated obesity-related liver lipotoxicity and dyslipidemia in C57BL/6J mice fed a HFC diet. In addition, the efficacy of oat fiber is greater than wheat bran fiber in normalizing these metabolic disorders and pathological profiles.

  1. Evaluation of non-azeotropic mixtures containing HFOs as potential refrigerants in refrigeration and high-temperature heat pump systems

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    With the increasing environmental concern on global warming, hydrofluoro-olefin (HFOs), possessing low GWP, has attracted great attention of many researchers recently. In this study, non-azeotropic mixtures composed of HFOs (HFO-1234yf, HFO-1234ze(z), HFO-1234ze(e) and HFO-1234zf) are developed to substitute for HFC-134a and CFC-114 in air-conditioning and high-temperature heat pump systems, respectively. The cycle performances were evaluated by an improved theoretical cy-cle evaluation methodology. The results showed that all the mixtures proposed herein were favorable refrigerants with excel-lent thermodynamic cycle performances. M1A presented lower discharge temperature and pressure ratio and higher COPc than that of HFC-134a. The volumetric cooling capacity was similar to HFC-134a. It can be served as a good environmentally friendly alternative to replace HFC-134a. M3H delivered similar discharge temperature as CFC-114 did. And the COPh was 3% higher. It exhibits excellent cycle performance in high-temperature heat pump and is a promising refrigerant to substitute for CFC-114. And the gliding temperature differences enable them to exhibit better coefficient of performance by matching the sink/source temperature in practice. Because the toxicity, flammability and other properties are not investigated in detail, ex-tensive toxicity and flammability testing needs to be conducted before they are used in a particular application.

  2. MISCIBILITY, SOLUBILITY, VISCOSITY, AND DENSITY MEASUREMENTS FOR R-236EA WITH FOUR DIFFERENT EXXON LUBRICANTS

    Science.gov (United States)

    The report discusses miscibility, solubility, viscosity, and density data for the refrigerant hydrofluorocarbon (HFC)-236ea (or R-236ea) and four lubricants supplied by Exxon Corporation. Such data are needed to determine the suitability of refrigerant/lubricant combinations for ...

  3. Emission quantification of refrigerant CFCs, HCFCs and HFCs in megacity Lahore (Pakistan) and contributed ODPs and GWPs

    Indian Academy of Sciences (India)

    Zia Ul-Haq; Muhammad Ali; Syeda Adila Batool; Salman Tariq; Zarmina Qayyum

    2016-08-01

    An integrated assessment of emissions of some important refrigerant ozone depleting substances (ODSs) (CFC-11, CFC-12, HCFC-141b and HFC-134a) and their contributed ozone depletion potentials (ODPs) and global warming potentials (GWPs) have been made in the megacity Lahore (Pakistan) for the periodfrom 2005 to 2013. During the production of 6.488 million refrigerator units, the cumulative estimated emissions of CFC-11, CFC-12, HCFC-141b and HFC-134a were 129.7, 6.8, 1257 and 104 mega grams (1 Mg = 106 grams). The estimated GWP (CO2-eq) and ODP (CFC 11-eq) associated with productionphase emissions of these four gases were 616.07, 73.52, 910.96, and 87.36 kilotonnes, and 129.7, 6.8, 139.4, and 0 tonnes, respectively. ODP of HFC-134a is considered to be zero. In addition, the repair and maintenance of 81.2 thousand units resulted in 10.8 Mg emissions of CFC-12 with 10.8 tonnes ODP(CFC11-eq) and 117,802 tonnes GWP (CO2-eq) that were higher than the HFC-134a emissions recorded at 4.3 Mg causing 4563 tonnes GWP(CO2-eq). A decrease in ODP (CFC 11-eq) and GWP (CO2-eq) at the rate of −8.3% and −8.2% per year is observed to be contributed by all the selected ODSs during the study period.

  4. 75 FR 74773 - Mandatory Reporting of Greenhouse Gases: Additional Sources of Fluorinated GHGs

    Science.gov (United States)

    2010-12-01

    ... greenhouse gas GWP global warming potential HAP hazardous air pollutant(s) HCFC hydrochlorofluorocarbon HFC... dioxide equivalent MRR mandatory greenhouse gas reporting rule MS mass spectrometry MVAC motor vehicle air... Protection Agency 40 CFR Part 98 Mandatory Reporting of Greenhouse Gases: Additional Sources of...

  5. An overview on non-CO2 greenhouse gases

    NARCIS (Netherlands)

    Pulles, T.; Amstel, van A.R.

    2010-01-01

    Non-CO2 greenhouse gases, included in the Kyoto Protocol, are methane (CH4), nitrous oxide (N2O), hexafluorocarbons (HFC), perfluorinated compounds (PFC) and sulphur hexafluoride (SF6). Together they account for about 25% of the present global greenhouse gas emissions. Reductions in emissions of the

  6. 40 CFR 98.158 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING HCFC-22 Production and HFC-23 Destruction § 98.158 Definitions. All terms used in... Service Emission factor(kg/hr/source) ≥10,000 ppmv Gas 0.0782 0.000131 Valves...

  7. 40 CFR 98.152 - GHGs to report.

    Science.gov (United States)

    2010-07-01

    ... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING HCFC-22 Production and HFC-23 Destruction § 98.152 GHGs to report. (a) You must report under subpart C of this part (General Stationary Fuel Combustion Sources) the emissions of...

  8. Investigating the highest melting temperature materials: A laser melting study of the TaC-HfC system

    Science.gov (United States)

    Cedillos-Barraza, Omar; Manara, Dario; Boboridis, K.; Watkins, Tyson; Grasso, Salvatore; Jayaseelan, Daniel D.; Konings, Rudy J. M.; Reece, Michael J.; Lee, William E.

    2016-12-01

    TaC, HfC and their solid solutions are promising candidate materials for thermal protection structures in hypersonic vehicles because of their very high melting temperatures (>4000 K) among other properties. The melting temperatures of slightly hypostoichiometric TaC, HfC and three solid solution compositions (Ta1‑xHfxC, with x = 0.8, 0.5 and 0.2) have long been identified as the highest known. In the current research, they were reassessed, for the first time in the last fifty years, using a laser heating technique. They were found to melt in the range of 4041–4232 K, with HfC having the highest and TaC the lowest. Spectral radiance of the hot samples was measured in situ, showing that the optical emissivity of these compounds plays a fundamental role in their heat balance. Independently, the results show that the melting point for HfC0.98, (4232 ± 84) K, is the highest recorded for any compound studied until now.

  9. 40 CFR Appendix D to Subpart G of... - Substitutes Subject to Use Restrictions and Unacceptable Substitutes

    Science.gov (United States)

    2010-07-01

    .... iii. The trade name, charge amount, and, when applicable, the ASHRAE refrigerant numerical designation... Comments Electronics Cleaning w/CFC-113 and MCF HFC-4310mee Acceptable Subject to a 200 ppm time-weighted... Electronics Cleaning w/CFC-113 and MCF Perfluoropolyethers Perfluoropolyethers are acceptable substitutes...

  10. Possible atmospheric lifetimes and chemical reaction mechanisms for selected HCFCs, HFCs, CH3CCl3, and their degradation products against dissolution and/or degradation in seawater and cloudwater

    Science.gov (United States)

    Wine, P. H.; Chameides, W. L.

    1990-01-01

    For a wide variety of atmospheric species including CO2, HNO3, and SO2, dissolution in seawater or cloudwater followed by hydrolysis or chemical reaction represents a primary pathway for removal from the atmosphere. In order to determine if this mechanism can also remove significant amounts of atmospheric chlorofluorocarbons (HCFC's), fluorocarbons (HFC's), and their degradation products, an investigation was undertaken as part of the Alternative Fluorocarbons Environmental Acceptability Study (AFEAS). In this investigation, the rates at which CHCl2CF3 (HCFC-123), CCl2FCH3 (HCFC-141b), CClF2CH3 (HCFC-142b), CHClF2 (HCFC-22), CHClFCF3 (HCFC-124) CH2FCF3 (HFC-134a) CHF2CH3 (HFC-152a), CHF2CF3 (HFC-125), and CH3CCl3 can be dissolved in the oceans and in cloudwater were estimated from the species' thermodynamic and chemical properties using simple mathematical formulations to simulate the transfer of gases from the atmosphere to the ocean or cloudwater. The ability of cloudwater and rainwater to remove gas phase degradation products of these compounds was also considered as was the aqueous phase chemistry of the degradation products. The results of this investigation are described.

  11. Bamboo shoot fiber prevents obesity in mice by modulating the gut microbiota

    Science.gov (United States)

    Li, Xiufen; Guo, Juan; Ji, Kailong; Zhang, Ping

    2016-01-01

    Dietary fiber has been shown to prevent high-fat diet induced obesity through modulating the gut microbiota; however, quality difference in fiber type is largely unknown. We performed a 6 week study on C57BL/6J mice fed a macronutrient matched high-fat diet with different fiber types including cellulose (HFC), bamboo shoot fiber (HFBS) and several other commonly consumed fibers. Our results showed that the HFBS group exhibited the lowest weight gain among all diet groups and had improved lipid profiles and glycemic control compared with the HFC group. As revealed by 16S rRNA gene sequencing, loss of diversity in the gut microbiota induced by the HFC diet was largely prevented by the HFBS diet. Moreover, compared with the HFC diet, the HFBS diet resulted in markedly increased relative abundance of Bacteroidetes and strong inhibition of Verrucomicrobia, two divisions strongly correlated with body weight. In conclusion, the present study provides evidence of a quality difference among different types of dietary fibers and shows that bamboo shoot fiber is the most effective in suppressing high-fat diet induced obesity. Our findings indicate that bamboo shoot fiber is a potential prebiotic fiber which modulates the gut microbiota and improves host metabolism. PMID:27599699

  12. Evaluating the Impact of a Connecticut Program to Reduce Availability of Unhealthy Competitive Food in Schools

    Science.gov (United States)

    Long, Michael W.; Henderson, Kathryn E.; Schwartz, Marlene B.

    2010-01-01

    Background: This article seeks to inform state and local school food policies by evaluating the impact of Connecticut's Healthy Food Certification (HFC), a program which provides monetary incentives to school districts that choose to implement state nutrition standards for all foods sold to students outside reimbursable school meals. Methods: Food…

  13. Carbon-Carbon High Melt Coating for Nozzle Extensions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The High Melt Coating system is applied to a carbon-carbon structure and embeds HfC, ZrB2 in the outer layers. ACC High Melt builds on the time tested base material...

  14. Rosuvastatin reduces plasma lipids by inhibiting VLDL production and enhancing hepatobiliary lipid excretion in ApoE*3-Leiden mice

    NARCIS (Netherlands)

    Delsing, DJM; Post, SM; Groenendijk, M; Solaas, K; van der Boom, H; van Duyvenvoorde, W; de Wit, ECM; Bloks, VW; Kuipers, F; Havekes, LM; Princen, HMG

    The present study was designed to investigate the lipid-lowering properties and mechanisms of action of a new HMG-CoA reductase inhibitor, rosuvastatin, in female ApoE*3-Leiden transgenic mice. Mice received a high fat/cholesterol (HFC) diet containing either rosuvastatin (0 [control], 0.00125%,

  15. Proceedings of the 1993 non-fluorocarbon insulation, refrigeration and air conditioning technology workshop

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

    Sessions included: HFC blown polyurethanes, carbon dioxide blown foam and extruded polystyrenes, plastic foam insulations, evacuated panel insulation, refrigeration and air conditioning, absorption and adsorption and stirling cycle refrigeration, innovative cooling technologies, and natural refrigerants. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  16. Kinetic studies of the thermal decomposition of KDNBF, a primer for explosives

    Energy Technology Data Exchange (ETDEWEB)

    Jones, D.E.G.; Feng, H.T.; Fouchard, R.C. [Natural Resources Canada, CANMET Canadian Explosives Research Laboratory, Ottawa, ON (Canada)

    2000-07-01

    The potassium salt of 4,6-dinitrobenzofuroxan (KDNBF) is used in primary explosive and propellant compositions, although very little is known about its thermal properties. This paper described an extensive thermal hazard assessment conducted using differential scanning calorimetry (DSC), thermal gravimetry (TG), accelerating rate calorimetry (ARC) and heat flux calorimetry (HFC) measurements. Dynamic and isothermal methods were used to determine kinetic parameters and activation energies. Results of the analyses indicated that KDNBF decomposed during a multi-step exothermic process that proceeded directly from the solid state. Decomposition was autocatalytic in a closed system. The decomposition process was not influenced by the surrounding atmosphere or gas environment except during the final stages of the TG decomposition in air, when remaining carbonaceous materials were converted into carbon dioxide (CO{sub 2}). The initial stage of decomposition was rapid enough for ignition to occur when too large a sample was used. The activation energy determined from the HFC analysis was lower than results obtained for the TG and ARC studies. It was concluded that mass to free volume ratios used in the HFC studies were more than double than the ratios used in the ARC measurements. It was concluded that higher pressures and an enhanced autocatalytic effect was observed in the gaseous decomposition products used in the HFC system. 9 refs., 1 tab., 13 figs.

  17. Emission quantification of refrigerant CFCs, HCFCs and HFCs in megacity Lahore (Pakistan) and contributed ODPs and GWPs

    Science.gov (United States)

    Ul-Haq, Zia; Ali, Muhammad; Batool, Syeda Adila; Tariq, Salman; Qayyum, Zarmina

    2016-08-01

    An integrated assessment of emissions of some important refrigerant ozone depleting substances (ODSs) (CFC-11, CFC-12, HCFC-141b and HFC-134a) and their contributed ozone depletion potentials (ODPs) and global warming potentials (GWPs) have been made in the megacity Lahore (Pakistan) for the period from 2005 to 2013. During the production of 6.488 million refrigerator units, the cumulative estimated emissions of CFC-11, CFC-12, HCFC-141b and HFC-134a were 129.7, 6.8, 1257 and 104 mega grams (1 Mg = 106 grams). The estimated GWP (CO2-eq) and ODP (CFC 11-eq) associated with production phase emissions of these four gases were 616.07, 73.52, 910.96, and 87.36 kilotonnes, and 129.7, 6.8, 139.4, and 0 tonnes, respectively. ODP of HFC-134a is considered to be zero. In addition, the repair and maintenance of 81.2 thousand units resulted in 10.8 Mg emissions of CFC-12 with 10.8 tonnes ODP(CFC 11-eq) and 117,802 tonnes GWP (CO2-eq) that were higher than the HFC-134a emissions recorded at 4.3 Mg causing 4563 tonnes GWP(CO2-eq). A decrease in ODP (CFC 11-eq) and GWP (CO2-eq) at the rate of -8.3% and -8.2% per year is observed to be contributed by all the selected ODSs during the study period.

  18. Performance and energy saving analysis of a refrigerator using hydrocarbon mixture (HC-R134a) as working fluid

    Science.gov (United States)

    Mohtar, M. N.; Nasution, H.; Aziz, A. A.

    2015-12-01

    The use of hydrocarbon mixture as a working fluid in a refrigerator system is rarely explored. Almost all domestic refrigerators use hydroflourocarbon R134a (HFC-R134a) as refrigerants. In this study, hydrocarbon gas (HC-R134a) is used as the alternative refrigerant to replace HFC-R134a. It has a composition of R290 (56%), R600a (54.39%) and additive (0.1%wt) blended for the trials. The experiments were conducted with 105 g and 52.5 g refrigerant mass charge, subjected to internal heat load of 0, 1, 2, 3 and 4 kg respectively. The study investigates the coefficient of performance of the refrigerator (COPR) and energy consumption. The results show that the use of HC-R134a as the replaceable refrigerant can save energy ranging from 2.04% to 7.09%, as compared to the conventional HFC-R134a refrigerant. Naturally, the COPR improvement and temperature distribution using HC-R134a are much better than HFC-R134a

  19. 76 FR 15249 - Deferral for CO2

    Science.gov (United States)

    2011-03-21

    ... GWP Global warming potential HFC Hydrofluorocarbon ICR Information Collection Request IPCC... methodologies for estimating all anthropogenic sources and sinks of GHG emissions at the national scale... global GHG. Carbon dioxide emissions from a subset of bioenergy sources are reported as information...

  20. Chocolate flavanols and skin photoprotection: a parallel, double-blind, randomized clinical trial

    Science.gov (United States)

    2014-01-01

    Background Solar ultraviolet (UV) radiation has deleterious effects on the skin, including sunburn, photoaging and cancer. Chocolate flavanols are naturally-occurring antioxidant and anti-inflammatory molecules that could play a role in preventing cutaneous UV damage. We investigated the influence of 12-week high-flavanol chocolate (HFC) consumption on skin sensitivity to UV radiation, measured by minimal erythema dose (MED). We also evaluated skin elasticity and hydration. Methods In this 2-group, parallel, double-blind, randomized controlled trial, 74 women aged 20–65 years and Fitzpatrick skin phototypes I or II were recruited from the general community in Quebec City, for randomization to either HFC (n = 33) or low-flavanol chocolate (LFC) (n = 41). A blocked randomisation (4), considering date of entry, skin type and age as factors, generated a sequentially-numbered allocation list. Study participants and research assistants were blinded. Totally, 30 g of chocolate were consumed daily for 12 weeks, followed by a 3-week washout period. MED was assessed at baseline and at 6, 9, 12 and 15 weeks. Main outcome was changes in MED at week 12. Results 33 participants in the HFC group and 41 in the LFC group were analyzed with 15 weeks of follow-up. Both groups showed similarly-increased MED at 12 weeks (HFC: 0.0252 ± 0.1099 J/cm2 [mean ± standard deviation (SD)]; LFC: 0.0151 ± 0.1118; mean difference (MD): 0.0100 J/cm2; 95% confidence interval (CI): -0.0417 to 0.0618). However, after 3-week washout, the HFC group presented decreased MED (-0.0248 ± 0.1145) whereas no effect was seen in the LFC group (0.0168 ± 0.1698) (MD: -0.0417; 95% CI: -0.1106 to 0.0272). Net temple elasticity increased slightly but significantly by 0.09 ± 0.12 mm in the HFC group at 12 weeks compared to 0.02 ± 0.12 mm in the LFC group (MD: 0.06; 95% CI: 0.01 to 0.12 ). No significant adverse events were reported. Conclusion Our study failed to

  1. Analysis of Chinese emissions trends of major halocarbons in monitoring the impacts of the Montreal Protocol

    Science.gov (United States)

    Li, S.; Park, S.; Park, M.; Kim, J.; Muhle, J.; Fang, X.; Stohl, A.; Weiss, R. F.; Kim, K.

    2013-12-01

    In this study we estimate the emission rates of anthropogenic halocarbons, which include CFC-11, CFC-12, HCFC-22, HCFC-141b, HCFC-142b, HFC-23, HFC-134a, HFC-32, HFC-125 and HFC-152a for China during the period of 2008 and 2012 using an interspecies correlation method (Kim et al., 2010; Li et al., 2011), which is a unique 'top-down' approach using in situ high-precision measurements at Gosan, a remote station on Jeju Island, Korea. Mixing ratios of ambient halocarbons have been measured every two hours using a cryogenic pre-concentration system coupled with gas chromatograph and mass selective detector (GC-MSD) as part of the Advanced Global Atmospheric Gases Experiment network. We first separated air-mass segments originating from China using a back-trajectory analysis to identify Chinese emission from the observations, and found that the mixing ratios of most of compounds presented significant correlations against those of HCFC-22. Based on the correlations, we analyzed emission strengths of individual compounds, which correspond to their slopes against HCFC-22 since the slope can be a useful proxy to demonstrate their emission trends with an assumption of relatively constant emission of HCFC-22 during the analysis period. The analysis showed about 14% increase in the emissions strengths of CFCs (mainly due to CFC-12) between 2008 and 2012 in China. Interestingly, HCFC-141b and HCFC-142b that are commonly known to be used for foam blowing agents revealed opposite trends in their emission strengths: ca. 48% increase of HCFC-141b versus ca. 22% decrease of HCFC-142b, suggesting the possibility of other major sources in case of China. The emission strengths of HFCs have been increasing due to significant emissions of HFC-32, HFC-125 and HFC-134a during the analysis period. However, HFC-23 which is a well-known byproduct of HCFC-22 production processes, showed decrease by about 22% in the emission strength. Reduction in HFC-23 emissions is most likely due to the

  2. An extended Kalman-filter for regional scale inverse emission estimation

    Directory of Open Access Journals (Sweden)

    D. Brunner

    2012-04-01

    Full Text Available A Kalman-filter based inverse emission estimation method for long-lived trace gases is presented for use in conjunction with a Lagrangian particle dispersion model like FLEXPART. The sequential nature of the approach allows tracing slow seasonal and interannual changes rather than estimating a single period-mean emission field. Other important features include the estimation of a slowly varying concentration background at each measurement station, the possibility to constrain the solution to non-negative emissions, the quantification of uncertainties, the consideration of temporal correlations in the residuals, and the applicability to potentially large inversion problems. The method is first demonstrated for a set of synthetic observations created from a prescribed emission field with different levels of (correlated noise, which closely mimics true observations. It is then applied to real observations of the three halocarbons HFC-125, HFC-152a and HCFC-141b at the remote research stations Jungfraujoch and Mace Head for the quantification of emissions in Western European countries from 2006 to 2010. Estimated HFC-125 emissions are mostly consistent with national totals reported to UNFCCC in the framework of the Kyoto Protocol and show a generally increasing trend over the considered period. Results for HFC-152a are much more variable with estimated emissions being both higher and lower than reported emissions in different countries. The highest emissions of the order of 700–800 Mg yr−1 are estimated for Italy, which so far does not report HFC-152a emissions. Emissions of HCFC-141b show a continuing strong decrease as expected due to its controls in developed countries under the Montreal Protocol. Emissions from France, however, were still rather large, in the range of 700–1000 Mg yr−1 in the years 2006 and 2007 but strongly declined thereafter.

  3. An extended Kalman-filter for regional scale inverse emission estimation

    Directory of Open Access Journals (Sweden)

    D. Brunner

    2011-10-01

    Full Text Available A Kalman-filter based inverse emission estimation method for long-lived trace gases is presented for use in conjunction with a Lagrangian particle dispersion model like FLEXPART. The sequential nature of the approach allows tracing slow seasonal and interannual changes rather than estimating a single period-mean emission field. Other important features include the estimation of a slowly varying concentration background at each measurement station, the possibility to constrain the solution to non-negative emissions, the quantification of uncertainties, the consideration of temporal correlations in the residuals, and the applicability to potentially large inversion problems. The method is first demonstrated for a set of synthetic observations created from a prescribed emission field with different levels of (correlated noise, which closely mimics true observations. It is then applied to real observations of the three halocarbons HFC-125, HFC-152a and HCFC-141b at the remote research stations Jungfraujoch and Mace Head for the quantification of emissions in Western European countries from 2006 to 2010. Estimated HFC-125 emissions are mostly consistent with national totals reported to the Kyoto protocol and show a generally increasing trend over the considered period. Results for HFC-152a are much more variable with estimated emissions being both higher and lower in different countries. The highest emissions of the order of 1000 Mg yr−1 are estimated for Italy which so far does not report HFC-152a emissions. Emissions of HCFC-141b show a continuing strong decrease as expected due to its ban under the Montreal Protocol. Emissions from France, however, were still rather large (near 1000 Mg yr−1 in the years 2006 and 2007 but strongly declined thereafter.

  4. An extended Kalman-filter for regional scale inverse emission estimation

    Science.gov (United States)

    Brunner, D.; Henne, S.; Keller, C. A.; Reimann, S.; Vollmer, M. K.; O'Doherty, S.; Maione, M.

    2012-04-01

    A Kalman-filter based inverse emission estimation method for long-lived trace gases is presented for use in conjunction with a Lagrangian particle dispersion model like FLEXPART. The sequential nature of the approach allows tracing slow seasonal and interannual changes rather than estimating a single period-mean emission field. Other important features include the estimation of a slowly varying concentration background at each measurement station, the possibility to constrain the solution to non-negative emissions, the quantification of uncertainties, the consideration of temporal correlations in the residuals, and the applicability to potentially large inversion problems. The method is first demonstrated for a set of synthetic observations created from a prescribed emission field with different levels of (correlated) noise, which closely mimics true observations. It is then applied to real observations of the three halocarbons HFC-125, HFC-152a and HCFC-141b at the remote research stations Jungfraujoch and Mace Head for the quantification of emissions in Western European countries from 2006 to 2010. Estimated HFC-125 emissions are mostly consistent with national totals reported to UNFCCC in the framework of the Kyoto Protocol and show a generally increasing trend over the considered period. Results for HFC-152a are much more variable with estimated emissions being both higher and lower than reported emissions in different countries. The highest emissions of the order of 700-800 Mg yr-1 are estimated for Italy, which so far does not report HFC-152a emissions. Emissions of HCFC-141b show a continuing strong decrease as expected due to its controls in developed countries under the Montreal Protocol. Emissions from France, however, were still rather large, in the range of 700-1000 Mg yr-1 in the years 2006 and 2007 but strongly declined thereafter.

  5. Historia y filosofía de las ciencias en la educación polimodal: propuesta para su incorporación al aula History and philosophy of science in science curricula: a proposal for its incorporation in science classes

    Directory of Open Access Journals (Sweden)

    Verónica Guridi

    2004-12-01

    Full Text Available Durante los últimos años se viene enfatizando la necesidad de la incorporación de la Historia y Filosofía de las Ciencias (HFC, en adelante a los currículos de Ciencias. Mucho se ha avanzado respecto de la definición de los marcos teóricos que debieran orientar la incorporación de la HFC en la Enseñanza de las Ciencias, pero sin embargo son pocos los trabajos que muestran propuestas concretas de incorporación de la HFC en las clases de Ciencias. Este trabajo intenta realizar un aporte en el sentido antes mencionado, presentando una propuesta para el tratamiento de un núcleo temático específico correspondiente al primer año Polimodal (orientación Humanidades y Ciencias Sociales en el espacio curricular Físico - Química. El núcleo temático seleccionado corresponde al estudio de la evolución de los modelos atómicos (hasta el modelo atómico de Bohr.In the last few years the necessity of including History and Philosophy of Science (HFC, hereafter in Science Curricula has been emphasised. There have been important advances in theoretical frameworks, which should orient the incorporation of HFC into Science classes. However, there are only a few works that include proposals that show some ways of making this concrete. This work attempts to make a contribution in that direction, presenting a proposal for the treatment of a specific thematic nucleus of the curricular area "Physics-Chemistry". The proposal is designed for the first year of High School Education (with orientation in Humanities and Social Sciences. The selected content corresponds to the study of the evolution of atomic models (up to the model of Bohr.

  6. The impact of heart failure clinic in the improvement on quality of life of heart failure patients in Mexico.

    Science.gov (United States)

    Mendez, Gustavo F; Betancourt, Lidia; Galicia-Mora, Guillermo

    2007-02-07

    Heart failure clinic (HFC) has emerged as an innovative strategy to improve prognosis and Quality of Life (QOL) of Heart Failure (HF) patients. Unfortunately, there is no-evidence of such benefit on HF patients by HFC in Latin-America. We undertake a research to investigate the impact of HFC on QOL in HF patients in Mexico. From October 2004 to July 2005 all patients that attended for the first time the HFC of the Specialties Hospital No 14 in Veracruz, Mexico were analysed. The study group included patients with HF and left ventricular systolic dysfunction (LVSD). QOL was measured by the Minnesota Living with Heart Failure Questionnaire (MLHFQ). MLHFQ score was compared between basal vs 6 months follow-up. Every patient served as his/her own control. Forty-five HF patients were included and 34 completed 6 months follow-up. Four patients died within 6 months (mortality rate 12% [95% CI 2-22%]). Of the 30 remaining patients, median age was 61 years (range 37-74 years) and 47% was women with a mean left ventricular ejection fraction of 34%. The MLHFQ had a significant reduction at 6 months compared with basal condition from the first evaluation (Basal vs 6 months: mean [SD], 50 [26] vs 31 [19]; p = 0.0001) with a strong correlation between the MLHFQ score and NYHA functional class (p = 0.001; r = 0.59). HFC improves QOL of HF patients in Mexico. This disease management strategy would be considered for widely use in Latin-America countries.

  7. Notat vedr. By- og Landskabsstyrelsens anmodning om en foreløbig vurdering af mulige konsekvenser på udpegningsgrundlaget for Natura 2000 område nr. 162 ved etablering af sommerhuse på Agersø og Orø (Notat til Skov- og Naturstyrelsen)

    DEFF Research Database (Denmark)

    Wind, Peter

    2008-01-01

      By- og Landskabsstyrelsen har med brev af den 30. maj 2008 anmodet Danmarks Miljøundersøgelser om at foretage en screening af mulige konsekvenser på udpegningsgrundlaget som anført ovenfor på baggrund af eksisterende data og viden.   I notatet gør DMU rede for mulige konsekvenser for udpegnings......  By- og Landskabsstyrelsen har med brev af den 30. maj 2008 anmodet Danmarks Miljøundersøgelser om at foretage en screening af mulige konsekvenser på udpegningsgrundlaget som anført ovenfor på baggrund af eksisterende data og viden.   I notatet gør DMU rede for mulige konsekvenser...

  8. Epilepsie und Schwangerschaft

    Directory of Open Access Journals (Sweden)

    Luef G

    2009-01-01

    Full Text Available Epilepsien sind eine der häufigsten neurologischen Erkrankungen und umfassen eine Vielzahl von heterogenen Erkrankungen, welche epileptische Anfälle als gemeinsames Symptom besitzen. Schwangerschaften epilepsiekranker Frauen beschäftigen Neurologen und Gynäkologen gleich häufig, da sowohl epileptische Anfälle mit tonisch-klonischen Krämpfen, als auch deren medikamentöse Therapie teratogen sein können. Über 90 % der Schwangerschaften epilepsiekranker Frauen verlaufen weitgehend problemlos. Auch die Anfallsfrequenz ist nur bei sehr wenigen Patientinnen gesteigert. Trotzdem ist es wichtig, dass im speziellen Fall schwangerer Epilepsiepatientinnen verschiedene Fachkräfte zusammenarbeiten. Eine Epilepsie stellt also in der Regel keinen Grund dar, auf Kinder zu verzichten.

  9. Blood pressure and atherosclerosis

    Institute of Scientific and Technical Information of China (English)

    1993-01-01

    930082 Clinical administration of atrial natri-uretic factor in reno-vascular hypertension.ZHANG Weiguo(张卫国),et al.Cardiovasc In-stit & Fuwai Hosp,CAMS,Beijing.Chin Cir J1992;7(5):450-452.In order to evaluate the effects of atrial natri-uretic factor(ANF)on patients with reno-vas-cular hypertension,α-hANF(0.025μg/kg/min×60min)was administered to 7 patients byi.v.drip..The renin-angiotensin-aldosteronesystem,plasma catecholamine and arginine va-sopressin were suppressed with diuresis and na-triuresis and lowering of blood pressure.The

  10. Computerized tomography analysis of aceptic necrosis of the femoral head

    Energy Technology Data Exchange (ETDEWEB)

    Ichioka, Yoshiaki; Masuda, Takeshi; Matsuno, Takeo; Hasegawa, Isao; Sugano, Hiroki; Konno, Takushi.

    1988-03-01

    Computerized tomography (CT) findings of the normal femoral head in 14 patients with unilateral aceptic necrosis of the femoral head (ANF) and in healthy adults were analyzed for early diagnostic significance. CT appearance of the bone trabeculae fell into normal finding, diffuse sclerosis, and mottled sclerosis. The development of necrosis during the process was accompanied by diffuse sclerosis, suggesting that diffuse sclerosis is an early CT appearance in the case of ANF. In a three-dimensional quantification of the necrotic area for 20 patients before rotational osteotomy of the femoral head, deformation of the femoral head after the surgery was found to frequently result from 50 % or more of the necrotic area in the femoral head, irrespective of the size of necrosis on the surface of the femoral head. This suggested the influence of the three-dimensional spread of necrosis on the intensity of the femoral head. (Namekawa, K.).

  11. Notat vedr. By- og Landskabsstyrelsens anmodning om en foreløbig vurdering af mulige konsekvenser på udpegningsgrundlaget for Natura 2000 område nr. 162 ved etablering af sommerhuse på Agersø og Orø (Notat til Skov- og Naturstyrelsen)

    DEFF Research Database (Denmark)

    Wind, Peter

    2008-01-01

      By- og Landskabsstyrelsen har med brev af den 30. maj 2008 anmodet Danmarks Miljøundersøgelser om at foretage en screening af mulige konsekvenser på udpegningsgrundlaget som anført ovenfor på baggrund af eksisterende data og viden.   I notatet gør DMU rede for mulige konsekvenser for udpegnings......  By- og Landskabsstyrelsen har med brev af den 30. maj 2008 anmodet Danmarks Miljøundersøgelser om at foretage en screening af mulige konsekvenser på udpegningsgrundlaget som anført ovenfor på baggrund af eksisterende data og viden.   I notatet gør DMU rede for mulige konsekvenser...

  12. Efeitos da crioterapia, estimulação elétrica transcutânea e da sua associação na atividade elétrica do nervo femoral em ratos

    OpenAIRE

    Santuzzi,CH; Gonçalves,WLS; Rocha,SS; Castro,MEC; Gouvea,SA; Abreu,GR

    2008-01-01

    CONTEXTUALIZAÇÃO: Relatos clínicos sugerem que a associação terapêutica entre crioterapia (CRIO) e estimulação elétrica transcutânea (TENS) favorece analgesia local. OBJETIVO: Avaliar a atividade elétrica do nervo femoral (ANF), em repouso e durante a aplicação isolada, e associada de TENS e CRIO em ratos. MÉTODOS: Foram utilizados nove ratos (Wistar) adultos com peso de ±300g. Após anestesia (Uretana, 1mg/g i.p.), o nervo femoral direito foi isolado para registro da ANF basal e durante as mo...

  13. Preparation and characterization of recombinant Llama VHH-human IgGFc chimeric antibody against H5N1 hemagglutinin from avian influenza virus%羊驼抗H5N1血凝素重链可变区-人IgGFc段嵌合抗体的制备和鉴定

    Institute of Scientific and Technical Information of China (English)

    夏立亮; 吴标; 程亚庭; 蔡家麟; 王颖; 赵国屏

    2012-01-01

    To prepare and characterize llama variable domain of heavy chain of heavy-chain antibody-human IgGlFc (VHH-hFc) chimeric antibody against hemagglutinin from H5N1 avian influenza virus, recombinant expression vector pET-22b-VHH23-hFc was constructed and VHH23-hFc chimeric antibody was expressed in E. coli BL2KDE3) strain by IPTG induction. As VHH23-hFc antibody was accumulated in inclusion bodies, two different refolding methods, dialysis and on-column refolding, were compared for the refolding efficacy and the optimal method was adopted for preparation of VHH23-hFc chimeric antibody. The activity and thermal stability of VHH antibodies were tested by ELISA. By using dialysis refolding procedure, VHH23-hFc chimeric antibody has been obtained with higher yield and good quality. The affinity constant of VHH23-hFc chimeric antibody was 2. 24 × 106 mol/L as determined by ELISA. VHH23-hFc chimeric antibody also displayed good thermal stability. The half-life span of VHH23-hFc chimeric antibody in mice was up to 35 hrs, which is comparable to conventional chimeric antibodies. Taken together, our results indicated that VHH23-hFc chimeric antibody against hemagglutinin derived from H5N1 avian influenza virus has been obtained with high activity, good thermal stability as well as longer half-life span, which provides basis for future functional study both in vitro and in vivo.%本研究旨在制备羊驼抗H5N1禽流感病毒的重链抗体可变区-人Fc段嵌合体抗体制备,对所得嵌合抗体进行制备和功能鉴定,为临床应用奠定基础.用pET-22b表达载体构建抗H5N1禽流感病毒羊驼重链可变区(VHH)-人IgG1Fc嵌合基因,以包涵体形式表达VHH23-hFc嵌合抗体蛋白,采用优化的方法复性后,获得高纯度VHH23-hFc嵌合抗体,用ELISA法鉴定嵌合抗体亲和力、热稳定性和小鼠体内的半衰期.结果显示,透析复性后原核表达的抗H5N1禽流感病毒VHH23-hFc嵌合抗体亲和力为2.24×106 mol/L,具有较好

  14. El corazón endocrino y el proceso inflamatorio

    Directory of Open Access Journals (Sweden)

    Tsuneo Ogawa

    2013-12-01

    Full Text Available El corazón endocrino, a través de sus hormonas polipéptidas atrial natriuretic factor (ANF o ANP y brain natriuretic peptide (BNP, contribuye a regular la precarga y la poscarga cardiacas. Otras importantes funciones se han descubierto recientemente incluyendo interacciones con el sistema inmunológico. Los niveles plasmáticos de BNP, no así los de ANF, aumentan durante un episodio de rechazo agudo del corazón alotransplantado pero retornan a niveles anteriores al episodio de rechazo después de un tratamiento exitoso del tal rechazo. Este fue el primer indicio que involucró el BNP y el sistema inmunológico. Otras patologías que tienen componentes inflamatorios también se ven acompañadas con cambios en la producción del BNP. El aumento del BNP tiene como base el aumento de la actividad transcripcional del gen inducida por citoquinas y substancias relacionadas. In vitro se puede demostrar que este aumento tiende a modular la actividad inmunológica. Inflamación y cambios hemodinámicos co-existen en la mayoría de las enfermedades cardiovasculares y por ende, es posible que sea beneficioso medir las dos hormonas como biomarcadores de cambios de volumen intravascular (ANF y de estos cambios más inflamación (BNP. Cambios en plasma de ANF relativamente más grandes que aquellos de BNP podrían indicar un deterioro hemodinámico, mientras que cambios importantes en BNP podrían ser indicativos de recrudecimiento del proceso inflamatorio.

  15. Designverifikation for fleksibel to-bladet mølle

    DEFF Research Database (Denmark)

    Vølund, P.; Rasmussen, Flemming

    1999-01-01

    konkurrenceforholdene mellem et sådant ekstremt koncept og meretraditionelle koncepter. Det skal anføres, at det omhandlede koncept er patentanmeldt af Risø. Det udførte arbejde er støttet af Energistyrelsen gennem EFP-95 projektet "Design af fleksibel rotor til dynamisk aktiv mølle" J.nr. 1363/95-0002, af EU gennemJOULE...

  16. Hidden Hearing Loss and Computational Models of the Auditory Pathway: Predicting Speech Intelligibility Decline

    Science.gov (United States)

    2016-11-28

    Title: Hidden Hearing Loss and Computational Models of the Auditory Pathway: Predicting Speech Intelligibility Decline Christopher J. Smalt...to utilize computational models of the auditory periphery and auditory cortex to study the effect of low spontaneous rate ANF loss on the cortical...clinical hearing thresholds is difficulty in understanding speech in noise. Recent animal studies have shown that noise exposure causes selective loss

  17. Wirksamkeit von impliziten und expliziten Lernprozessen : Aneignung taktischer Kompetenzen und motorischer Fertigkeiten im Basketball

    OpenAIRE

    Calábria Lopes, Mariana

    2011-01-01

    Das Hauptziel der vorliegenden Studie war die Untersuchung der Frage, welche Effekte implizite und explizite Lernprozesse und eine Kombination aus beiden auf technische Fertigkeiten und taktische Kompetenzen von Anfängern im Basketball haben. Zur Überprüfung dieser Fragestellung wurden 86 Probanden zwischen 9 und 12 Jahre in drei Interventionsgruppen (explizite, implizite und implizit-explizite Gruppe) und eine Kontrollgruppe aufgeteilt, die in einem Messwiederholungsdesign getestet wurden. D...

  18. Circulant Matrices and Affine Equivalence of Monomial Rotation Symmetric Boolean Functions

    Science.gov (United States)

    2015-01-01

    Received in revised form 15 October 2014 Accepted 17 May 2015 Keywords: Boolean functions Circulant matrices Affine equivalence Permutations a b s t... representation of f is called the algebraic normal form (ANF) of f . The number of variables in the highest order product term with nonzero... representation of f (not unique, since one can choose any representative in Gn(x1xi2 . . . xil)) is called the short algebraic normal form (SANF) of f

  19. Affine Equivalence of Quartic Monomial Rotation Symmetric Boolean Functions in Prime Power Dimension

    Science.gov (United States)

    2015-01-27

    ANF. This representation of f (not unique, since one can choose any representative in Gn(x1xi2 . . . xil)) is called the short algebraic normal form ...Affine Equivalence of Quartic Monomial Rotation Symmetric Boolean Functions in Prime Power Dimension Pantelimon Stănică Naval Postgraduate School...Boolean functions, circulant matrices, affine equivalence , permutations, prime powers. Mathematics Subject Classification [2010]: 94A60, 94C10, 06E30 1

  20. Effect of Dietary Exogenous Enzyme Supplementation on Enteric Mucosal Morphological Development and Adherent Mucin Thickness in Turkeys

    Directory of Open Access Journals (Sweden)

    Ayuub A. Ayoola

    2015-10-01

    Full Text Available Anti-nutritional factors in feed ingredients (ANF can challenge gut health and reduce nutrient utilization. Birds typically activate their innate immune system as a protective response against the adverse effects of ANF, which often involves the secretion of mucin. Although dietary supplementation of exogenous enzymes are commonly used to alleviate the adverse effects of ANF on apparent nutrient digestibility, little is known about how they affect gut health, particularly in relation to the morphological development and mucin secretion of enteric mucosa. We carried out two trials to examine the effect of dietary supplementation of different types of exogenous enzymes on gut health of by accessing the effect of jejunum morphological development and ileal enteric adherent mucin thickness layer in turkeys. Dietary β-mannanase supplementation reduced ileal adherent mucin thickness layer (804 µg/g vs 823 µg/g; p<0.05, while a commercial blend of Xylanase, Amylase and Protease (XAP reduced ileal adherent mucin layer thickness (589 µg/g vs 740 µg/g; p<0.05; thus reducing the apparent endogenous loss of nutrients. Both enzyme supplements also affected gut morphological characteristics. In comparison to the control treatment, dietary β-mannanase supplementation improved the jejunum tip width (219 vs 161; p<0.05, base width (367 vs 300; p<0.05, surface area (509,870 vs 380, 157; p<0.05 and villi height/crypt depth ratio (7.49 vs 5.70; p<0.05, and XAP improved the crypt depth (p<0.05. In conclusion dietary supplementation of exogenous enzymes may help alleviate the adverse effects of ANF on nutrient utilization by directly or indirectly removing the mucosal irritation that stimulates enteric mucin secretion.

  1. Diversity of Nitrogenase Systems in Diazotrophs

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Nitrogenase is a metalloprotein complex that catalyses the reaction of biological nitrogen fixation. At least three genetically distinct nitrogenase systems have been confirmed in diazotrophs, namely Nif, Vnf, and Anf, in which the active-site central metals are Mo, V, and Fe, respectively. The present review summarizes progress on the genetic, structural, and functional investigations into the three nitrogenases and discusses the possibility of the existence of other novel nitrogenases.

  2. Effects of moderate-level sound exposure on behavioral thresholds in chinchillas

    OpenAIRE

    Carbajal de Nava, Maria Sandra

    2015-01-01

    Normal audiometric thresholds following noise exposure have generally been considered as an indication of a recovered cochlea and intact peripheral auditory system, yet recent animal work has challenged this classic assumption. Moderately noise-exposed animals have been shown to have permanent loss of synapses on inner hair cells (IHCs) and permanent damage to auditory nerve fibers (ANFs), specifically the low-spontaneous rate fibers (low-SR), despite normal electrophysiological thresholds. L...

  3. Mutationsanalyse im KCNAB1-Gen bei Rolando-Epilepsie

    OpenAIRE

    2012-01-01

    Epilepsien gehören zu den häufigsten neurologischen Erkrankungen. Ätiologisch unterscheidet man symptomatische Epilepsien, bei denen das Anfallsgeschehen Ausdruck einer Läsion oder Vorerkrankung des Zentralnervensystems ist, von den idiopathischen (genetischen) Epilepsien, denen eine polygene genetische Disposition zugrunde liegt. In exemplarischen Großfamilien konnten vielfach Defekte in Ionenkanalgenen gefunden werden. Die klinische Charakteristik epileptischer Anfälle und der elektroenzep...

  4. Final Report for USDoD ARO Grant No. W911NF-05-1-0282 (University of Minnesota)

    Science.gov (United States)

    2009-08-14

    across bits. The constraints take into account not only the transmission energy but also the power consumed by the transceiver’s circuitry. Furthermore... efficent resource allocation in wireless relay transmissions In recent years, relay transmissions have attracted a lot of attention owing to the...the energy required for transmitting one information bit under three different relay schemes: amplify and forward (AnF), decode and forward (DnF

  5. A Report of Research on Detection of Deception

    Science.gov (United States)

    1952-09-15

    the circulatory system: Tho basic variablus 36 -nd th, i rJiati ons XIi W’ktods of wmasuring circulatory variables 49 XITI tr,aing rPpors..: Physiolo...shovnx in Tabla T. In all group, thero was anf icrao c-rf-o to look toward the guilty qundIrrnt. This incroase Ocakirred vih2.’hor subjocts wero

  6. Atrial natriuretic factor in the acute nephritic and nephrotic syndromes.

    Science.gov (United States)

    Rodríguez-Iturbe, B; Colic, D; Parra, G; Gutkowska, J

    1990-09-01

    Because the role of systemic hormones in the pathophysiology of edema in acute renal disease remains incompletely understood, we compared the levels of atrial natriuretic factor (ANF) and plasma renin activity (PRA) in patients with acute glomerulonephritis (AGN), nephrotic syndrome (NS), and normal individuals during salt deprivation and salt loading. Sixteen patients with AGN (10 males) and nine patients with NS and hypoalbuminemia (7 males) were studied on admission, and after recovery (12 AGN patients) or remission (4 NS patients). Eighteen normal controls were each studied after five days on a low (20 mEq Na/day), regular (120 mEq Na/day) and high (300 mEq Na/day) dietary salt intake. Patients with AGN and NS had comparable edema (AGN 2.8 +/- 0.53 kg; NS 3.36 +/- 0.47 kg; SE) and urinary Na excretion (mean +/- SEM: AGN 0.97 +/- 0.11 mEq/hr; NS 1.06 +/- 0.16 mEq/hr), but AGN patients had five times higher ANF (AGN 27.2 +/- 4.06 fmol/ml; NS 5.51 +/- 1.02 fmol/ml; P less than 0.001) and six times lower PRA ng/liter.sec levels (AGN 0.187 +/- 0.047; NS 1.144 +/- 0.222; P less than 0.001) than NS patients. The degree of edema was correlated with ANF levels in AGN patients (P less than 0.001) but not in NS patients. There was a strong exponential negative correlation (r = -0.773, P less than 0.0001) between ANF and PRA, in which AGN patients and Na-restricted controls were located in the opposite ends of the volume sensing-response, and NS patients in the middle, alongside controls with regular Na intake.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Weltkonjunktur im Herbst 2014

    OpenAIRE

    2014-01-01

    [Weltwirtschaftliche Expansion ohne Schwung] Die weltwirtschaftliche Expansion ist im Verlauf des Jahres 2014 erneut ins Stocken geraten. Von einem Aufschwung, der von allen Regionen getragen wird, ist die Weltwirtschaft weit entfernt. Sie bleibt anfällig für Störungen, sei es durch geopolitische Entwicklungen, sei es durch Turbulenzen an den Finanzmärkten. Wir erwarten zwar, dass sich die Weltkonjunktur im kommenden Jahr festigt, die Dynamik wird aber wohl vorerst moderat bleiben. Getragen w...

  8. Geschichte des ökologischen Landbaus im deutschsprachigen Raum [History of organic agriculture in the German-speaking region

    OpenAIRE

    2001-01-01

    Erste Ansätze zu ökologischer Landbewirtschaftung gab es bereits Ende des 19. Jahrhunderts. Neben den Anfängen des ökologischen Landbaus beleuchtet der Autor auch das Umfeld, in dem ökologischer Landbau entstanden ist. Themen: Entstehungskontext des ökologischen Landbaus Abfolge der ökologischen Landbausysteme Natürlicher Landbau Biologisch-dynamische Wirtschaftsweise Organisch-Biologischer Landbau Biologischer Landbau Ökologischer Lannbau der organisch-biologischen L...

  9. Kritik af gældende ret om udbetaling af forsikring og pension ved død samt forslag til nye regler

    DEFF Research Database (Denmark)

    Feldthusen, Rasmus Kristian; Mortensen, Anne Kjærhus

    2013-01-01

    Med afsæt i en analyse af gældende ret peger forfatterne i artiklen på en række uhensigtsmæssigheder ved det gældende system for udbetaling af forsikring og pension ved død. Det konkluderes, at de nugældende regler i forsikringsaftalelovens § 104 /pensionsopsparingslovens § 4 om anfægtelse af en ...

  10. Late pancreatic metastasis of renal cell carcinoma with absence of FDG-uptake in PET-CT

    Directory of Open Access Journals (Sweden)

    Elif Karadeli

    2016-03-01

    Full Text Available The primary tumors, which raise isolated pancreas metastases are frequently of renal origin, where colorectal cancer, melanoma, breast and lung cancers and sarcoma are the following causes of metastatic pancreas cancer . In this article, we present a case of pancreas-metastatic renal cell carcinoma with its radiological features, which did not exert anF-18 FDG-uptake in the whole-body positron emission tomography (PET. [Cukurova Med J 2016; 41(0.100: 92-94

  11. SNS ønsker DMUs (eventuelle) bemærkninger til de nye oplysninger i sagen. Dianthus caryophyllus (123.2.38/ 123.2.2). Supplerende materiale til Nellike-sagen. Modtaget 23-09-2005, deadline 13-10-2005, svar 13-10-2005

    DEFF Research Database (Denmark)

    Kjellsson, Gøsta; Damgaard, Christian

    2005-01-01

    bl.a. af manglen på forvildede nellikearter i dyrkningsområderne i Sydeuropa. 3. Risiko for genspredning ved krydsninger. Det anføres at der kan ske genspredning fra Florigene-nelliken ved krydsninger med dyrkede D. sylvestris i fx Sydeuropa. DMU er, som det også fremgår af vores tidligere...... derfor ingen indsigelser mod markedsføringen i EU af Florigene nelliken som afskårne blomster. "...

  12. A model of synaptic vesicle-pool depletion and replenishment can account for the interspike interval distributions and nonrenewal properties of spontaneous spike trains of auditory-nerve fibers.

    Science.gov (United States)

    Peterson, Adam J; Irvine, Dexter R F; Heil, Peter

    2014-11-05

    In mammalian auditory systems, the spiking characteristics of each primary afferent (type I auditory-nerve fiber; ANF) are mainly determined by a single ribbon synapse in a single receptor cell (inner hair cell; IHC). ANF spike trains therefore provide a window into the operation of these synapses and cells. It was demonstrated previously (Heil et al., 2007) that the distribution of interspike intervals (ISIs) of cat ANFs during spontaneous activity can be modeled as resulting from refractoriness operating on a non-Poisson stochastic point process of excitation (transmitter release events from the IHC). Here, we investigate nonrenewal properties of these cat-ANF spontaneous spike trains, manifest as negative serial ISI correlations and reduced spike-count variability over short timescales. A previously discussed excitatory process, the constrained failure of events from a homogeneous Poisson point process, can account for these properties, but does not offer a parsimonious explanation for certain trends in the data. We then investigate a three-parameter model of vesicle-pool depletion and replenishment and find that it accounts for all experimental observations, including the ISI distributions, with only the release probability varying between spike trains. The maximum number of units (single vesicles or groups of simultaneously released vesicles) in the readily releasable pool and their replenishment time constant can be assumed to be constant (∼4 and 13.5 ms, respectively). We suggest that the organization of the IHC ribbon synapses not only enables sustained release of neurotransmitter but also imposes temporal regularity on the release process, particularly when operating at high rates. Copyright © 2014 the authors 0270-6474/14/3415097-13$15.00/0.

  13. Effects of rates of spontaneous synaptic vesicle secretions in inner hair cells on information transmission in an auditory nerve fiber model.

    Science.gov (United States)

    Kumsa, Parichat; Mino, Hiroyuki

    2012-01-01

    In this article, we investigate how the rates of spontaneous synaptic vesicle secretions affect information transmission of the spike trains in response to the inner hair cell (IHC) synaptic currents in an auditory nerve fiber (ANF) model through computer simulations. The IHC synaptic currents were modeled by a filtered inhomogeneous Poisson process modulated with sinusoidal functions, while the stochastic ion channel model was incorporated into each node of Ranvier in the ANF model with spiral ganglion. The information rates were estimated from the entropies of the inter-spike intervals of the spike trains to evaluate information transmission in the ANF model. The results show that the information rates increased, reached a maximum, and then decreased as the rate of spontaneous secretion increased, implying a resonance phenomenon dependent on the rate of spontaneous IHC synaptic secretions. In conclusion, this phenomenon similar to the regular stochastic resonance may be observed due to that spontaneous IHC synaptic secretions may act as an origin of fluctuation or noise, and these findings may play a key role in the design of better auditory prostheses.

  14. An influence of spontaneous spike rates on information transmission in a spherical bushy neuron model with stochastic ion channels.

    Science.gov (United States)

    Arata, Hiroki; Mino, Hiroyuki

    2012-01-01

    This article presents an effect of spontaneous spike firing rates on information transmission of the spike trains in a spherical bushy neuron model of antero-ventral cochlear nuclei. In computer simulations, the synaptic current stimuli ascending from auditory nerve fibers (ANFs) were modeled by a filtered inhomogeneous Poisson process modulated with sinusoidal functions, while the stochastic sodium and stochastic high- and low-threshold potassium channels were incorporated into a single compartment model of the soma in spherical bushy neurons. The information rates were estimated from the entropies of the inter-spike intervals of the spike trains to quantitatively evaluate information transmission in the spherical busy neuron model. The results show that the information rates increased, reached a maximum, and then decreased as the rate of spontaneous spikes from the ANFs increased, implying a resonance phenomenon dependent on the rate of spontaneous spikes from ANFs. In conclusion, this phenomenon similar to the stochastic resonance would be observed due to that spontaneous random spike firings coming from auditory nerves may act as an origin of fluctuation or noise, and these findings may play a key role in the design of better auditory prostheses.

  15. Protective Effect of Chitin Urocanate Nanofibers against Ultraviolet Radiation

    Directory of Open Access Journals (Sweden)

    Ikuko Ito

    2015-12-01

    Full Text Available Urocanic acid is a major ultraviolet (UV-absorbing chromophore. Chitins are highly crystalline structures that are found predominantly in crustacean shells. Alpha-chitin consists of microfibers that contain nanofibrils embedded in a protein matrix. Acid hydrolysis is a common method used to prepare chitin nanofibrils (NFs. We typically obtain NFs by hydrolyzing chitin with acetic acid. However, in the present study, we used urocanic acid to prepare urocanic acid chitin NFs (UNFs and examined its protective effect against UVB radiation. Hos: HR-1 mice coated with UNFs were UVB irradiated (302 nm, 150 mJ/cm2, and these mice showed markedly lower UVB radiation-induced cutaneous erythema than the control. Additionally, sunburn cells were rarely detected in the epidermis of UNFs-coated mice after UVB irradiation. Although the difference was not as significant as UNFs, the number of sunburn cells in mice treated with acetic acid chitin nanofibrils (ANFs tended to be lower than in control mice. These results demonstrate that ANFs have a protective effect against UVB and suggest that the anti-inflammatory and antioxidant effects of NFs influence the protective effect of ANFs against UVB radiation. The combination of NFs with other substances that possess UV-protective effects, such as urocanic acid, may provide an enhanced protective effect against UVB radiation.

  16. Unbalance vibration suppression for AMBs system using adaptive notch filter

    Science.gov (United States)

    Chen, Qi; Liu, Gang; Han, Bangcheng

    2017-09-01

    The unbalance of rotor levitated by active magnetic bearings (AMBs) will cause synchronous vibration which greatly degrade the performance at high speeds in the rotating machinery. To suppress the unbalance vibration without angular velocity information, a novel modified adaptive notch filter (ANF) with phase shift in the AMBs system is presented in this study. Firstly, a 4-degree-of-freedom (DOF) radial unbalanced AMB rotor system is described and analyzed, and the solution of rotor vibration displacement is compared with the experimental data to verify the preciseness of the dynamic model. Then the principle and structure of the proposed notch filter used for the frequency estimation and online identification of synchronous component are presented. As well, the convergence property of the algorithm is investigated. In addition, the stability analysis of the closed-loop AMB system with the proposed ANF is conducted. Simulation and experiments on an AMB driveline system demonstrate the effectiveness and the adaptive characteristics of the proposed ANF on the elimination of synchronous controlled current in a widely operating speed range.

  17. Perforated appendiceal diverticulitis associated with appendiceal neurofibroma in neurofibromatosis type 1.

    Science.gov (United States)

    Ozaki, Akihiko; Tsukada, Manabu; Watanabe, Kazuo; Tsubokura, Masaharu; Kato, Shigeaki; Tanimoto, Tetsuya; Kami, Masahiro; Ohira, Hiromichi; Kanazawa, Yukio

    2015-09-07

    An appendiceal neurofibroma (ANF) is a rare neoplasm associated with neurofibromatosis type 1(NF-1), an inheritable neurocutaneous disorder that involves multiple systems including the intraabdominal organs. Appendiceal diverticulitis occasionally ruptures in the absence of intense abdominal pain, which can lead to serious consequences. Recent reports highlight the association between appendiceal diverticulum and appendiceal neoplasms; however, there is still little information on the association between appendiceal diverticulitis and ANF in NF-1. A 51-year-old Japanese male with NF-1 was referred to the division of surgery for mild right lower quadrant pain. It was suspected he had perforated acute appendicitis with periappendiceal abscess based on clinical manifestations and findings of computed tomography. An emergency appendectomy was conducted. The pathological examination revealed diffusely proliferated tumor cells of a neurofibroma, coexistent with multiple appendiceal diverticulums, leading to the diagnosis of perforated appendiceal diverticulitis associated with ANF. Although he developed a remnant abscess, he recovered with the conservative treatments of antibiotics and drainage. This case suggests that appendiceal diverticulitis might be a complication of appendiceal involvement of NF-1, and that it occasionally ruptures in the absence of intense abdominal pain. Clinicians should recognize that NF-1 can cause various abdominal manifestations.

  18. The heart as an endocrine organ.

    Science.gov (United States)

    Ogawa, Tsuneo; de Bold, Adolfo J

    2014-01-01

    The concept of the heart as an endocrine organ arises from the observation that the atrial cardiomyocytes in the mammalian heart display a phenotype that is partly that of endocrine cells. Investigations carried out between 1971 and 1983 characterised, by virtue of its natriuretic properties, a polypeptide referred to atrial natriuretic factor (ANF). Another polypeptide isolated from brain in 1988, brain natriuretic peptide (BNP), was subsequently characterised as a second hormone produced by the mammalian heart atria. These peptides were associated with the maintenance of extracellular fluid volume and blood pressure. Later work demonstrated a plethora of other properties for ANF and BNP, now designated cardiac natriuretic peptides (cNPs). In addition to the cNPs, other polypeptide hormones are expressed in the heart that likely act upon the myocardium in a paracrine or autocrine fashion. These include the C-type natriuretic peptide, adrenomedullin, proadrenomedullin N-terminal peptide and endothelin-1. Expression and secretion of ANF and BNP are increased in various cardiovascular pathologies and their levels in blood are used in the diagnosis and prognosis of cardiovascular disease. In addition, therapeutic uses for these peptides or related substances have been found. In all, the discovery of the endocrine heart provided a shift from the classical functional paradigm of the heart that regarded this organ solely as a blood pump to one that regards this organ as self-regulating its workload humorally and that also influences the function of several other organs that control cardiovascular function.

  19. Australian Nursing Informatics Competency Project.

    Science.gov (United States)

    Foster, Joanne; Bryce, Julianne

    2009-01-01

    A study of Australian nurses on their use of information technology in the workplace was undertaken by the Australian Nursing Federation (ANF) in 2007. This study of over 4000 nurses highlighted that nurses recognise benefits to adopting more information technology in the workplace although there are significant barriers to their use. It also identified gross deficits in the capacity of the nursing workforce to engage in the digital processing of information. Following the release of the study last year, the ANF commenced work on a number of key recommendations from the report in order to overcome identified barriers and provide opportunities for nurses to better utilise information technology and information management systems. One of these recommendations was to seek research funding to develop national information technology and information management competency standards for nurses. This project has now received Federal Government funding to undertake this development. This project is being developed in collaboration with the ANF and the Queensland University of Technology. This paper will discuss the methodology, development and publication of the Australian Nursing Informatics Competency Standards Project which is currently underway and due for completion in May 2009. The Australian Nursing Informatics Competencies will be presented at the conference.

  20. The role of cytochrome P4501A activity inhibition in three- to five-ringed polycyclic aromatic hydrocarbons embryotoxicity of marine medaka (Oryzias melastigma).

    Science.gov (United States)

    Mu, Jing-li; Wang, Xin-hong; Jin, Fei; Wang, Ju-ying; Hong, Hua-sheng

    2012-07-01

    The mode of action of PAHs that causes fish developmental malformations is unclear. The embryotoxicity of marine medaka (Oryzias melastigma) was investigated after individual exposure to three- to five-ring PAHs Phe, Py, and BaP or co-exposure with α-ANF for 18 days. We found that the relationships between EROD induction and developmental deformities of embryos showed a various pattern under different exposure scenarios of Phe, Py, and BaP, which suggested possibly different modes of action in determining the developmental toxicities. As for co-exposure scenarios of each PAH combined with ANF, it showed potentially synergistic effects. The inhibited CYP1A mediated enzyme activity by ANF after co-exposure did not effectively alleviate developmental toxicity of embryo. It showed potentially synergistic effects after co-exposure of marine fish embryos to CYP1A inhibitors and PAH-type CYP1A inducers. Heart deformities in the early life stages of marine medaka were recommended as a biomarker for indicating the extent of PAH pollution.

  1. An analytical inversion method for determining regional and global emissions of greenhouse gases: Sensitivity studies and application to halocarbons

    Directory of Open Access Journals (Sweden)

    A. Stohl

    2009-03-01

    Full Text Available A new analytical inversion method has been developed to determine the regional and global emissions of long-lived atmospheric trace gases. It exploits in situ measurement data from three global networks and builds on backward simulations with a Lagrangian particle dispersion model. The emission information is extracted from the observed concentration increases over a baseline that is itself objectively determined by the inversion algorithm. The method was applied to two hydrofluorocarbons (HFC-134a, HFC-152a and a hydrochlorofluorocarbon (HCFC-22 for the period January 2005 until March 2007. Detailed sensitivity studies with synthetic as well as with real measurement data were done to quantify the influence on the results of the a priori emissions and their uncertainties as well as of the observation and model errors. It was found that the global a posteriori emissions of HFC-134a, HFC-152a and HCFC-22 all increased from 2005 to 2006. Large increases (21%, 16%, 18%, respectively from 2005 to 2006 were found for China, whereas the emission changes in North America (−9%, 23%, 17%, respectively and Europe (11%, 11%, −4%, respectively were mostly smaller and less systematic. For Europe, the a posteriori emissions of HFC-134a and HFC-152a were slightly higher than the a priori emissions reported to the United Nations Framework Convention on Climate Change (UNFCCC. For HCFC-22, the a posteriori emissions for Europe were substantially (by almost a factor 2 higher than the a priori emissions used, which were based on HCFC consumption data reported to the United Nations Environment Programme (UNEP. Combined with the reported strongly decreasing HCFC consumption in Europe, this suggests a substantial time lag between the reported time of the HCFC-22 consumption and the actual time of the HCFC-22 emission. Conversely, in China where HCFC consumption is increasing rapidly according to the UNEP data, the a posteriori emissions are only about 40% of the a

  2. OD ESR detection of the radical anions of cyclic nitrones in liquid solutions

    Science.gov (United States)

    Barlukova, M. M.; Gritsan, N. P.; Bagryansky, V. A.; Starichenko, V. F.; Grigor'ev, I. A.; Molin, Yu. N.

    2005-01-01

    The radical anions of five-membered cyclic nitrone spin traps, 3,3,5,5-tetramethyl-1-pyrroline-1-oxide and 1,2,2,5,5-pentamethyl-3-imidazoline-3-oxide, formed under radiolysis of liquid squalane solutions at 250-268 K, were registered by the method of optically detected ESR, and the hfc constants and g-values of the radical anions were determined. The hfc constants of these radical anions were predicted by DFT calculations and were found to be in quantitative agreement with experiment. It was demonstrated that radical anions of the five-membered cyclic nitrones have non-planar geometry with the spin density localized in the C dbnd N sbnd O fragment.

  3. Thermal Expansion of Hafnium Carbide

    Science.gov (United States)

    Grisaffe, Salvatore J.

    1960-01-01

    Since hafnium carbide (HfC) has a melting point of 7029 deg. F, it may have many high-temperature applications. A literature search uncovered very little information about the properties of HfC, and so a program was initiated at the Lewis Research Center to determine some of the physical properties of this material. This note presents the results of the thermal expansion investigation. The thermal-expansion measurements were made with a Gaertner dilatation interferometer calibrated to an accuracy of +/- 1 deg. F. This device indicates expansion by the movement of fringes produced by the cancellation and reinforcement of fixed wave-length light rays which are reflected from the surfaces of two parallel quartz glass disks. The test specimens which separate these disks are three small cones, each approximately 0.20 in. high.

  4. Advanced rescue techniques: lessons learned from the collapse of a building in Nairobi, Kenya.

    Science.gov (United States)

    Rokach, Ariel; Nemet, Dani; Dudkiewicz, Mickey; Albalansi, Alberto; Pinkert, Moshe; Schwartz, Dagan; Bar-Dayan, Yaron

    2009-04-01

    This paper examines the collapse of a five-storey building in Nairobi, Kenya, on 23 January 2006. It draws on reports from local authorities and on debriefings by Israel's Home Front Command (HFC), including information on injury distribution, rescue techniques, and the mode of operation. Most of the 117 people found under the structure were evacuated on the first day to a public hospital, which was overwhelmed by the incident. HFC forces arrived 23 hours after the disaster. At that stage, two people were still buried under the building and special techniques (tunnelling and scalping) were required to secure their evacuation. The two people quickly recovered after a short stay in hospital. Local technology is the preferred option during such events because time is crucial. International cooperation is required when this technology is not available. All of the hospitals in the disaster area, including private facilities, should participate in treating casualties.

  5. 含二茂铁基β-二酮钌(Ⅲ)螯合物的合成和热分析%The Synthesis and Thermoanalysis for the Chelated Compounds of Ru (Ⅲ) β-Diketonates Containing Ferrocenyl Substituent

    Institute of Scientific and Technical Information of China (English)

    陆锦成; 张炎成; 卞君和; 卞君和

    1981-01-01

    @@ 含二茂铁基β-二酮的一些金属螯合物合成近年来已有研究[1,2],但有关它的钌螯合物合成迄今未见文献报导。我们对此进行了初步研究,首次合成了二茂铁甲酰丙酮(HFcA)(FcCOCH,COCH3)和二茂铁甲酰三氟丙酮HFcTA)(FcCOCH2COCF3)的金属钌(Ⅲ)螯合物,对它们的吸收光谱作了测定,用热重(TG)、热差(DTA)方法进行热性能分析,同时与乙酰丙酮钌(RuA3)作了对照。

  6. Wet-spinnability and crosslinked fibre properties of two collagen polypeptides with varied molecular weight

    CERN Document Server

    Tronci, Giuseppe; Arafat, M Tarik; Yin, Jie; Wood, David J; Russell, Stephen J

    2015-01-01

    The formation of naturally-derived materials with wet stable fibrous architectures is paramount in order to mimic the features of tissues at the molecular and microscopic scale. Here, we investigated the formation of wet-spun fibres based on collagen-derived polypeptides with comparable chemical composition and varied molecular weight. Gelatin and hydrolysed fish collagen (HFC) were selected as widely-available linear amino-acidic chains of high and low molecular weight, respectively, and functionalised in the wet-spun fibre state in order to preserve the material geometry in physiological conditions. Wet-spun fibre diameter and morphology were dramatically affected depending on the polypeptide molecular weight, wet-spinning solvent (i.e. 2,2,2-Trifluoroethanol and dimethyl sulfoxide) and coagulating medium (i.e. acetone and ethanol), resulting in either bulky or porous internal geometry. Dry-state tensile moduli were significantly enhanced in gelatin and HFC samples following covalent crosslinking with activ...

  7. Insertion of historical and philosophical components in disciplines of the natural sciences in the medium teaching: reflections from the historiographies controversies among Kuhn and Lakatos

    Directory of Open Access Journals (Sweden)

    Osmar Henrique Moura da Silv

    2010-12-01

    Full Text Available The incorporation of historical and philosophical elements in disciplines of natural sciences of the high school has been reaching defended in the specific literature and critics improved visions concerning the use of the History and Philosophy of the Science (HFC for didactic ends. In that sense, the discussions are important since ponder influences in the orientation of curricula of significant portion of the undergraduate teaching. Worrying about such discussions, this study put reflections about de historiographies controversies among Kuhn and Lakatos whose educational implications allow support to a tendency of the use of HFC as resources not to obtain completely authentic historical reconstructions, but to favor intentions of to develop and to project didactic solutions in that the pedagogy doesn't need to submit itself to the History.

  8. Adaptive digital access protocol: new features and performance improvements

    Science.gov (United States)

    Doshi, B. T.; Dravida, S.; Kustka, G. J.; Magill, Peter D.; Siller, Curtis A., Jr.; Kotikalapudi, Sriram

    1996-11-01

    This paper reports on a broadband multiple access protocol for bi-directional hybrid fiber-coax (HFC) networks. Referred to here as the enhanced adaptive digital access protocol (ADAPt+TM), it builds upon earlier work to define a medium access control (MAC) protocol amenable to a multiple service environment supporting subscriber access in HFC networks with tree and branch topologies. ADAPt+ efficiently supports different access modes such as synchronous transfer mode (STM), asynchronous transfer mode (ATM), and variable length (VL) native data (e.g., IP, IPX). This enhanced protocol adapts to changing demands for a mix of circuit- and packet-mode applications, and efficiently allocates upstream and downstream bandwidth to isochronous and bursty traffic sources. This paper describes: ADAPt+ for upstream communication and multiplexing/demultiplexing for downstream communication; its applicability to STM, ATM and other native data applications; and performance attributes such as bandwidth efficiency and latency.

  9. International research into chlorofluorocarbon (CFC) alternatives

    Energy Technology Data Exchange (ETDEWEB)

    Marseille, T.J.; Shankle, D.L.; Thurman, A.G.

    1992-05-01

    Selected researchers from 21 countries were queried through questionnaires about their current and planned research activities. The results of the survey show that the majority of research being conducted by the respondents is devoted to investigating the hydrogenated fluorocarbon HFC-134a as a replacement for CFC-12 in refrigeration applications. The main issue with this alternative is identifying compatible lubricants that do not reduce its effectiveness.

  10. Two-phase Flow Distribution in Heat Exchanger Manifolds

    OpenAIRE

    Vist, Sivert

    2004-01-01

    The current study has investigated two-phase refrigerant flow distribution in heat exchange manifolds. Experimental data have been acquired in a heat exchanger test rig specially made for measurement of mass flow rate and gas and liquid distribution in the manifolds of compact heat exchangers. Twelve different manifold designs were used in the experiments, and CO2 and HFC-134a were used as refrigerants.

  11. Alternative Refrigerant Evaluation for High-Ambient-Temperature Environments: R-22 and R-410A Alternatives for Rooftop Air Conditioners

    Energy Technology Data Exchange (ETDEWEB)

    Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shrestha, Som S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shen, Bo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Linkous, Randall Lee [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Goetzler, William [Navigant Consulting Inc., Burlington, MA (United States); Guernsey, Matt [Navigant Consulting Inc., Burlington, MA (United States); Bargach, Youssef [Navigant Consulting Inc., Burlington, MA (United States)

    2016-09-01

    The Oak Ridge National Laboratory (ORNL) High-Ambient-Temperature Evaluation Program for Low-Global Warming Potential (Low-GWP) Refrigerants aims to develop an understanding of the performance of low-GWP alternative refrigerants relative to hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants in packaged or Rooftop Unit (RTU) air conditioners under high-ambient-temperature conditions. This final report describes the parties involved, the alternative refrigerants selection process, the test procedures, and the final results.

  12. Reactive Spark Plasma Sintering (SPS) of Nitride Reinforced Titanium Alloy Composites (Postprint)

    Science.gov (United States)

    2014-08-15

    ies on in situ alloying and reactions during the SPS process. A recent study on SPS processing of hafnium carbide (HfC) starting from a blend of...AFRL-RX-WP-JA-2014-0177 REACTIVE SPARK PLASMA SINTERING (SPS) OF NITRIDE REINFORCED TITANIUM ALLOY COMPOSITES (POSTPRINT) Jaimie S...SINTERING (SPS) OF NITRIDE REINFORCED TITANIUM ALLOY COMPOSITES (POSTPRINT) 5a. CONTRACT NUMBER In-House 5b. GRANT NUMBER 5c. PROGRAM ELEMENT

  13. Deproteinase Effect of Hydrocolloid Flour Made of “Gembili Tuber” (Dioscorea esculenta L. on Chemical and Technical Functional Properties

    Directory of Open Access Journals (Sweden)

    Herlina Herlina

    2015-01-01

    Full Text Available Hydrocolloid flour extracted of gembili tuber studied in this research to know the chemical and technical functional properties. Hydrocolloid flour extracted directly with distilled water (HFC and hydrocolloid flour which has reduced protein (deproteinase by hydrolysis with 0.05% protease of Aspergillus oryzae (HFD. Compared to the chemical properties and technical functional properties covering proximate test, total sugars, solubility, power and emulsion stability, power and  foaming stability, water holding capacity (WHC, oil holding capacity (OHC, viscosity to changes in temperature and viscosity to changes in pH. The results showed that different test t-test (α = 0.05 moisture content, ash content and fat content between HFC and HFD not significant, while the levels of protein and carbohydrates are significant. Deproteinase the process of hydrocolloid  flour made of  gembili tuber with 0.05% protease enzyme use in the extraction able to lower protein content by 49.57% and increase of carbohydrates by 11.39%.   In addition, the process deproteinase effect the technical functional properties of hydrocolloid flour increase solubility, emulsion stability, foam stability, WHC and OHC. Increasing in the temperature by  10-90 °C lower the viscosity by 70%  (56.33 ± 0.19mp to 17.05 ± 0.03 mp of HFC and  73% (26.16 ± 1.28 mp to 7 , 08 ± 0.79 mp of HFD. The highest viscosity hydrocolloids flour (HFC and HFD contained at pH 7 and decrease with acidic or alkaline conditions.

  14. Carbon Dioxide as Secondary Refrigerant in Supermarkets

    DEFF Research Database (Denmark)

    Knudsen, Hans Jørgen Høgaard

    Resume I forbindelse med udfasning af HCFC- og HFC-kølemidlerne er opstået stor interesse for anvendelse af naturlige kølemidler samt indirekte køling i forbindelse med køling i supermarkeder. Som sekundært kølemiddel med faseskift kan kuldioxid anvendes. I supermarkeder med køleanlægget placeret...

  15. ETUDE ET CONCEPTION D'UN DISPOSITIF DE REFRIGERATION MAGNETIQUE BASE SUR L'EFFET MAGNETOCALORIQUE GEANT

    OpenAIRE

    Allab, Farid

    2008-01-01

    The various environmental agreements prohibit the use of usual refrigerants (protocol of Montreal: FC and HCFC and protocol of Kyoto: HFC). It is thus relevant to carry out, in parallel to the current work on the new refrigerating fluids, a research of new solutions of refrigeration ensuring high energy effectiveness and a weak environmental impact. The magnetic refrigeration constitutes one of the solutions. This technology is based on the magnetocaloric effect (MCE), an intrinsic property o...

  16. Carbon dioxide emission implications if hydrofluorocarbons are regulated: a refrigeration case study.

    Science.gov (United States)

    Blowers, Paul; Lownsbury, James M

    2010-03-01

    The U.S. is strongly considering regulating hydrofluorocarbons (HFCs) due to their global climate change forcing effects. A drop-in replacement hydrofluoroether has been evaluated using a gate-to-grave life cycle assessment of greenhouse gas emissions for the trade-offs between direct and indirect carbon dioxide equivalent emissions compared to a current HFC and a historically used refrigerant. The results indicate current regulations being considered may increase global climate change.

  17. New Technologies and Materials for Enhanced Damage and Fire Tolerance of Naval Vessels

    Science.gov (United States)

    2011-02-01

    toxicity, flammability and exposure potential. Gaseous agents on the list deemed feasible for use in normally occupied spaces include HFC-227ea...required to sustain the combustion process it will extinguish. Inert substances, such as talc (hydrated magnesium silicate) and chalk (calcium... exposure test * A minimum of five specimens from each of the warp and fill directions on materials of the same lot shall be tested and their results

  18. Alternative Refrigerant Evaluation for High-Ambient Temperature Environments: R-22 and R-410A Alternatives for Mini-Split Air Conditioners

    Energy Technology Data Exchange (ETDEWEB)

    Abdelaziz, Omar [ORNL; Munk, Jeffrey D [ORNL; Shrestha, Som S [ORNL; Linkous, Randall Lee [ORNL; Goetzler, William [Navigant Consulting Inc.; Guernsey, Matt [Navigant Consulting Inc.; Kassuga, Theo [Navigant Consulting Inc.

    2015-08-01

    The Oak Ridge National Laboratory (ORNL) High-Ambient Temperature Testing Program for Low-GWP Refrigerants aims to develop an understanding of the performance of low-Global Warming Potential (low-GWP) alternatives to Hydrochlorofluorocarbon (HCFC) and Hydrofluorocarbon (HFC) refrigerants in mini-split air conditioners under high ambient temperature conditions. This interim working paper describes the parties involved, the alternative refrigerants selection process, the test procedures, and the preliminary results.

  19. Alternative Refrigerant Evaluation for High-Ambient-Temperature Environments: R-22 and R-410A Alternatives for Mini-Split Air Conditioners

    Energy Technology Data Exchange (ETDEWEB)

    Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shrestha, Som S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Munk, Jeffrey D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Linkous, Randall Lee [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Goetzler, William [Navigant Consulting Inc., Burlington, MA (United States); Guernsey, Matt [Navigant Consulting Inc., Burlington, MA (United States); Kassuga, Theo [Navigant Consulting Inc., Burlington, MA (United States)

    2015-10-01

    The Oak Ridge National Laboratory (ORNL) High-Ambient-Temperature Evaluation Program for low– global warming potential (Low-GWP) Refrigerants aims to develop an understanding of the performance of low-GWP alternative refrigerants to hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants in mini-split air conditioners under high-ambient-temperature conditions. This final report describes the parties involved, the alternative refrigerant selection process, the test procedures, and the final results.

  20. Staudinger ketene-imine cycloaddition, RCM approach to macrocrocyclic bisazetidinones.

    Science.gov (United States)

    Ibrahim, Yehia A; Al-Azemi, Talal F; Abd El-Halim, Mohamed D; John, Elizabeth

    2009-06-05

    Application of Staudinger ketene-imine cycloaddition reaction to bis-o-allyloxyarylideneamines afforded the corresponding bisallyloxyazetidinones as the cis-cis diastereomers, exclusively obtained as a mixture of cis-syn-cis and cis-anti-cis. RCM of the latter using Grubbs' catalysts afforded the corresponding macrocyclic bisazetidinones in good yields. The cis-anti-cis bisazetidinones are readily identified by (1)H NMR using Eu(hfc)(3) chiral shift reagent.

  1. Development and Stability Verification of a Measuring Installation of Saturation Liquid Density%饱和液体密度测量装置的研制与可靠性验证

    Institute of Scientific and Technical Information of China (English)

    徐英杰; 李鹏; 高赞军; 闵旭伟; 韩晓红; 陈光明

    2013-01-01

    本文研制了一种用于测量制冷剂饱和液体密度的实验装置,该装置主要由恒温系统与测量系统组成,其中密度的测量精度为--0.5 kg/m3.本文以纯质制冷剂HCFC-22与混合制冷剂HFC-407C为例分别在该实验装置进行了实验测试.结果表明,无论是纯质还是混合制冷剂的液体密度实验测量结果都与文献值具有良好的一致性.在此基础上,本文还用该实验装置对HFC-407C在温度为244~337 K范围内的饱和液体密度进行更细致而又精确的测量,并分别采用VDNS型方程与Rackett型方程对HFC-407C实验数据进行了关联,得到各自的方程参数及适用于HFC-407C的预测模型.所有这些研究为纯质与混合工质在实际工程中的应用打下了坚实的基础.

  2. Greenhouse effect: an issue for the refrigeration and air conditioning sector; Effet de serre: quelle problematique pour le froid et le conditionnement de l`air?

    Energy Technology Data Exchange (ETDEWEB)

    Billiard, F. [Institut International du Froid, 75 - Paris (France)

    1997-12-31

    The principles of greenhouse effect and the greenhouse gas main direct and indirect emission sources due to refrigeration and air conditioning systems are first reviewed. Evolution scenarios from 1992 to 2020 and 2100 for the emissions of CFC, HCFC and HFC are presented and related to the Kyoto protocol project limitations; technical improvements in refrigerating and air conditioning systems (lower refrigerant utilization, fluid confinement, alternative technologies, natural refrigerant utilization, etc.) could lead to substantial diminutions of these greenhouse gases

  3. 中华轿车空调系统的检修

    Institute of Scientific and Technical Information of China (English)

    段明社

    2008-01-01

    中华轿车空调系统采用双向全流空气混合系统,具有独立的脸部空气送风功能和冷空气旁通功能,采用V50可变排量空调压缩机,R-134a(HFC-134a)制冷剂。

  4. 广电专业技术用语名词中、英文对照

    Institute of Scientific and Technical Information of China (English)

    杨保平; 杨雨竹

    2003-01-01

    Lightwave CATV System光纤有线电视系统 HFC Network ……光纤同轴电缆混合网 Photo-detector 光探测器 Optical Fiber AM CATV光纤调幅有线电视 Switching Power Supply开关电源 Uninterruptible Power Supply不间断电源 Set-Top Converter 机上变换器 CRT Color AnalyzerCRT色彩分析仪

  5. Reducing Hazardous Emissions at Anniston Army Depot

    Science.gov (United States)

    2012-05-01

    2800 Powder Mill Road,Adelphi,MD,20783-1197 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10...grease, dirt/sand, carbon and powder residue, copper, lead, and brass fouling, plating wax, and other contaminants  Up to two select...alkaline detergent DuPont Vertrel SDG Hydrofluorocarbon (HFC)-based immersion vapor degreaser with ultrasonics 3M HFE-72DE Hydrofluoroether (HFE

  6. Uptake of trifluoroacetate by Pinus ponderosa via atmospheric pathway

    Science.gov (United States)

    Benesch, J. A.; Gustin, M. S.

    Trifluoroacetate (TFA, CF 3COO -), a break down product of hydro(chloro)-fluorocarbons (HFC/HCFCs), has been suggested to contribute to forest decline syndrome. To investigate the possible effects, Pinus ponderosa was exposed to TFA applied as mist (150 and 10,000 ng l -1) to foliar surfaces. Needles accumulated TFA as a function of concentration and time. However, no adverse physiological responses, as plant morphology, photosynthetic and conductance rates, were observed at the TFA concentrations used in this study.

  7. Experimental study on crystallization process and formation rate of a mixed gas hydrate%混合气体水合物结晶生成过程及其反应速度的实验研究

    Institute of Scientific and Technical Information of China (English)

    赵永利; 郭开华; 曾丽; 樊拴狮

    2002-01-01

    对混合制冷剂气体水合物HCFC141b/HFC152a在不同外部条件下的结晶生成速度进行了实验研究,通过数据分析得到了水合物结晶生成速度和冷却介质温度、扰动速度、制冷剂比份的依变关系.

  8. Studies of Ultra High Temperature Ceramic Composite Components: Synthesis and Characterization of HfOxCy and Si Oxidation in Atomic Oxygen Containing Environments

    Science.gov (United States)

    2008-08-01

    protective coatings since either HfC was produced with either carbon vacancies or oxygen inclusion or the films had non-uniform properties. The preparation ...thin films prepared by laser ablation: material distribution and droplet problem, Mater. Sci. Eng., 1992, B13, 67-74. 13. Gyorgy E., Mihailescu...Adsorption of atomic oxygen and nitrogen at β- Cristobalite (100): a density functonal theory study, J. Phys. Chem. B, 2005, 109, 14954-14964. 8

  9. PRELIMINARY DATA ON FUMONISINS PRESENCE IN PIG LIVER

    Directory of Open Access Journals (Sweden)

    B. Lugoboni

    2009-12-01

    Full Text Available Mycotoxins are heterogeneous chemical compounds characterized by a low molecular weight and synthesized by the secondary metabolism of different molds. Fumonisins are water-soluble mycotoxins produced by Fusarium species spoiling corn and derived products. These mycotoxins can enter the food chain also through the consumption of meat of exposed animals. Fumonisins and their metabolites have been associated with several animal and human diseases. They are suspected risk factors for esophageal and liver cancers, neural tube defects and cardiovascular problems. Improved methods are needed to accurately assess fumonisin concentrations in food from vegetable and animal origin to prevent acute and chronic human exposure. The aim of the present work was to develop a sensitive and selective method for quantification and unambiguous identification of fumonisin B1 (FB1, fumonisin B2 (FB2 and their complete hydrolyzed products (HFB1 and HFB2, in order to determine their presence in pig liver. Furthermore, the developed method was applied, in order to test its efficacy, on liver samples of weaned piglets fed a diet in compliance with the FB1 and FB2 contamination limits set by EU. All the samples showed the presence of at least one of the analytes. In particular FB1 was found in 5 out of 7 samples and the average level of contamination found was 28 ppb.

  10. Toxicity assessment of fumonisins using the brine shrimp (Artemia salina) bioassay.

    Science.gov (United States)

    Hartl, M; Humpf, H U

    2000-12-01

    The Fusarium mycotoxins fumonisin B(1) (FB(1)) (1) and B(2) (FB(2)) (2), their hydrolysed analogues HFB(1) (3) and HFB(2) (4) and the recently discovered fumonisin derivatives N-palmitoyl-HFB(1) (5) and N-carboxymethyl-FB(1) (6) were compared for their toxicity in a short term bioassay using brine shrimp (Artemia salina). The brine shrimp were hatched in artificial sea water and exposed to the fumonisins in microwell plates with a mortality endpoint after 48 hours. LC(50) values were calculated after Probit transformation of the resulting data. Of the substances tested, fumonisin B(1) emerged to be the most toxic whereas its N-carboxymethyl analogue was 100-fold less effective. The hydrolysed fumonisins showed a four- to sixfold reduced toxicity compared to FB(1). N-Palmitoyl-HFB(1) had a higher LC(50) value than its precursor HFB(1). The brine shrimp assay proved to be a convenient and rapid system for toxicity assessment of this group of mycotoxins.

  11. Multiscale Modeling of UHTC: Thermal Conductivity

    Science.gov (United States)

    Lawson, John W.; Murry, Daw; Squire, Thomas; Bauschlicher, Charles W.

    2012-01-01

    We are developing a multiscale framework in computational modeling for the ultra high temperature ceramics (UHTC) ZrB2 and HfB2. These materials are characterized by high melting point, good strength, and reasonable oxidation resistance. They are candidate materials for a number of applications in extreme environments including sharp leading edges of hypersonic aircraft. In particular, we used a combination of ab initio methods, atomistic simulations and continuum computations to obtain insights into fundamental properties of these materials. Ab initio methods were used to compute basic structural, mechanical and thermal properties. From these results, a database was constructed to fit a Tersoff style interatomic potential suitable for atomistic simulations. These potentials were used to evaluate the lattice thermal conductivity of single crystals and the thermal resistance of simple grain boundaries. Finite element method (FEM) computations using atomistic results as inputs were performed with meshes constructed on SEM images thereby modeling the realistic microstructure. These continuum computations showed the reduction in thermal conductivity due to the grain boundary network.

  12. Ultra High Temperature Ceramics' Processing Routes and Microstructures Compared

    Science.gov (United States)

    Gusman, Michael; Stackpoole, Mairead; Johnson, Sylvia; Gasch, Matt; Lau, Kai-Hung; Sanjurjo, Angel

    2009-01-01

    Ultra High Temperature Ceramics (UHTCs), such as HfB2 and ZrB2 composites containing SiC, are known to have good thermal shock resistance and high thermal conductivity at elevated temperatures. These UHTCs have been proposed for a number of structural applications in hypersonic vehicles, nozzles, and sharp leading edges. NASA Ames is working on controlling UHTC properties (especially, mechanical properties, thermal conductivity, and oxidation resistance) through processing, composition, and microstructure. In addition to using traditional methods of combining additives to boride powders, we are preparing UHTCs using coat ing powders to produce both borides and additives. These coatings and additions to the powders are used to manipulate and control grain-boundary composition and second- and third-phase variations within the UHTCs. Controlling the composition of high temperature oxidation by-products is also an important consideration. The powders are consolidated by hot-pressing or field-assisted sintering (FAS). Comparisons of microstructures and hardness data will be presented.

  13. Multiphase Nano-Composite Coatings for Achieving Energy Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Nainaparampil, Jose

    2012-03-26

    UES Inc. and ANL teamed in this work to develop novel coating systems for the protection of surfaces from thermal degradation mainly in two applications; Machining and Die casting. These coatings were specifically designed for the purpose by incorporating required material phases and the overall architecture, which led to reduce the energy usage and increase efficiency of the operations. Following the UES/ANL's feasibility work, the coatings were developed utilizing High power impulse magnetron sputtering (HiPMS) and Large area filtered arc deposition (LAFAD) techniques. Toughness, hardness and oxidation resistance: contrasting qualities have been mixed in the right proportion to attain the suitable material characteristic for the cause. Hafnium diboride (HfB2) based materials provided such a system and its properties were tamed to attain the right combination of toughness and hardness by working on the microstructure and architecture of coatings. An effective interfacing material (graded concentrations of topcoat) was also achieved in this work to provide the required adhesion between the substrate and the coating. Combination of an appropriate bond coat and a functional top coat provided the present thermal degradation resistant coating for cutting tools and die-casting applications. Laboratory level performance tests and industrial level application tests by partner companies (Beta Site Testing) were used for the development of these coatings.

  14. Masses, Deformations and Charge Radii--Nuclear Ground-State Properties in the Relativistic Mean Field Model

    CERN Document Server

    Geng, L S; Meng, J

    2005-01-01

    We perform a systematic study of the ground-state properties of all the nuclei from the proton drip line to the neutron drip line throughout the periodic table employing the relativistic mean field model. The TMA parameter set is used for the mean-field Lagrangian density, and a state-dependent BCS method is adopted to describe the pairing correlation. The ground-state properties of a total of 6969 nuclei with $Z,N\\ge 8$ and $Z\\le 100$ from the proton drip line to the neutron drip line, including the binding energies, the separation energies, the deformations, and the rms charge radii, are calculated and compared with existing experimental data and those of the FRDM and HFB-2 mass formulae. This study provides the first complete picture of the current status of the descriptions of nuclear ground-state properties in the relativistic mean field model. The deviations from existing experimental data indicate either that new degrees of freedom are needed, such as triaxial deformations, or that serious effort is ne...

  15. Experimental study and modelling of heat transfer during condensation of pure fluid and binary mixture on a bundle of horizontal finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Belghazi, M.; Marvillet, C. [Commissariat a l' Energie Atomique, Grenoble (France). Groupement pour la Recherche sur les Echangeurs thermiques; Bontemps, A. [Universite Joseph Fourier, Grenoble (France). LEGI/GRETh

    2003-03-01

    An experimental investigation was conducted to measure the local heat transfer coefficient for each row in a trapezoidal finned horizontal tube bundle during condensation of both pure fluid (HFC 134a) and several compositions of the non-azeotropic binary mixture HFC 23/HFC 134a. The test section is a 13x3 (rows x columns) tube bundle and the heat transfer coefficient is measured using the modified Wilson plot method. The inlet vapour temperature is fixed at 40{sup o}C and the water flow rate in each active row ranges from 170 to 600 l/h. The test series cover five different finned tubes all commercially available, K11 (11 fins/inch), K19 (19 fins/inch), K26 (26 fins/inch), K32 (32 fins/inch), K40 (40 fins/inch) and their performances were compared. The experimental results were checked against available models predicting the heat transfer coefficient during condensation of pure fluids on banks of finned tubes. Modelling of heat exchange during condensation of binary mixtures on bundles of finned tubes based on the curve condensation model is presented. (author)

  16. Substitutes for potent green house gases. HFCs, PFCs and SF{sub 6}. Status report

    Energy Technology Data Exchange (ETDEWEB)

    Pedersen, P.H. [Dansk Teknologisk Institut (Denmark)

    1997-12-31

    CFCs (halogenated chlorofluorocarbons), HCFCs (hydrochlorofluorocarbons), HFCs (hydrofluorocarbons), PFCs (fluorocarbons) and SF{sub 6} (sulphur hexafluoride) are all artificial substances which were not to be found in nature until recently. In 1995 the Danish consumption of HFC substances was approximately 740 tonnes, where the corresponding amount of SF{sub 6} was about 17 tonnes. If the entire amount of these substances was released to to the atmosphere, the resulting impact would correspond to an increased emission of greenhouse gases, corresponding to approximately 1.5 million tonnes of CO{sub 2}. HFC substances would account for 73%, SF{sub 6} with 25% and PFC for 1%. This corresponds to approximately 2.6% of the Danish CO{sub 2} emission (nearly 60 million tonnes per year). This corresponds to about half of the aimed 6% reduction of CO{sub 2} emission attained by introduction of mandatory green taxes on CO{sub 2}. According to experience from the CFC programme it is possible to recover some CFC and send it to controlled destruction. From 1993 to 1996 the refrigeration industry, for instance, has returned a total amount of 163 tonnes of CFC refrigerant through the KMO organization (Koelebranchens Miljoe Ordning). Most of this has been destroyed and a small amount has been purified and recycled afterwards. Similarly, it is likely to believe that some HFC refrigerant will be returned through the KMO organization. (au) 11 refs., also published in Danish

  17. Setting safe acute exposure limits for halon replacement chemicals using physiologically based pharmacokinetic modeling.

    Science.gov (United States)

    Vinegar, A; Jepson, G W; Cisneros, M; Rubenstein, R; Brock, W J

    2000-08-01

    Most proposed replacements for Halon 1301 as a fire suppressant are halogenated hydrocarbons. The acute toxic endpoint of concern for these agents is cardiac sensitization. An approach is described that links the cardiac endpoint as assessed in dogs to a target arterial concentration in humans. Linkage was made using a physiologically based pharmacokinetic (PBPK) model. Monte Carlo simulations, which account for population variability, were used to establish safe exposure times at different exposure concentrations for Halon 1301 (bromotrifluoromethane), CF(3)I (trifluoroiodomethane), HFC-125 (pentafluoroethane), HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane), and HFC-236fa (1,1,1,3,3,3-hexafluoropropane). Application of the modeling technique described here not only makes use of the conservative cardiac sensitization endpoint, but also uses an understanding of the pharmacokinetics of the chemical agents to better establish standards for safe exposure. The combined application of cardiac sensitization data and physiologically based modeling provides a quantitative approach, which can facilitate the selection and effective use of halon replacement candidates.

  18. High-global warming potential F-gas emissions in California: comparison of ambient-based versus inventory-based emission estimates, and implications of refined estimates.

    Science.gov (United States)

    Gallagher, Glenn; Zhan, Tao; Hsu, Ying-Kuang; Gupta, Pamela; Pederson, James; Croes, Bart; Blake, Donald R; Barletta, Barbara; Meinardi, Simone; Ashford, Paul; Vetter, Arnie; Saba, Sabine; Slim, Rayan; Palandre, Lionel; Clodic, Denis; Mathis, Pamela; Wagner, Mark; Forgie, Julia; Dwyer, Harry; Wolf, Katy

    2014-01-21

    To provide information for greenhouse gas reduction policies, the California Air Resources Board (CARB) inventories annual emissions of high-global-warming potential (GWP) fluorinated gases, the fastest growing sector of greenhouse gas (GHG) emissions globally. Baseline 2008 F-gas emissions estimates for selected chlorofluorocarbons (CFC-12), hydrochlorofluorocarbons (HCFC-22), and hydrofluorocarbons (HFC-134a) made with an inventory-based methodology were compared to emissions estimates made by ambient-based measurements. Significant discrepancies were found, with the inventory-based emissions methodology resulting in a systematic 42% under-estimation of CFC-12 emissions from older refrigeration equipment and older vehicles, and a systematic 114% overestimation of emissions for HFC-134a, a refrigerant substitute for phased-out CFCs. Initial, inventory-based estimates for all F-gas emissions had assumed that equipment is no longer in service once it reaches its average lifetime of use. Revised emission estimates using improved models for equipment age at end-of-life, inventories, and leak rates specific to California resulted in F-gas emissions estimates in closer agreement to ambient-based measurements. The discrepancies between inventory-based estimates and ambient-based measurements were reduced from -42% to -6% for CFC-12, and from +114% to +9% for HFC-134a.

  19. Emissions of halocarbons from mobile vehicle air conditioning system in Hong Kong.

    Science.gov (United States)

    Yan, H H; Guo, H; Ou, J M

    2014-08-15

    During the implementation of Montreal Protocol, emission inventories of halocarbons in different sectors at regional scale are fundamental to the formulation of relevant management strategy and inspection of the implementation efficiency. This study investigated the emission profile of halocarbons used in the mobile vehicle air conditioning system, the leading sector of refrigeration industry in terms of the refrigerant bank, market and emission, in the Hong Kong Special Administrative Region, using a bottom-up approach developed by 2006 IPCC Good Practice Guidance. The results showed that emissions of CFC-12 peaked at 53 tons ODP (Ozone Depletion Potential) in 1992 and then gradually diminished, whereas HFC-134a presented an increasing emission trend since 1990s and the emissions of HFC-134a reached 65,000 tons CO2-equivelant (CO2-eq) by the end of 2011. Uncertainty analysis revealed relatively high levels of uncertainties for special-purpose vehicles and government vehicles. Moreover, greenhouse gas (GHG) abatements under different scenarios indicated that potential emission reduction of HFC-134a ranged from 4.1 to 8.4 × 10(5)tons CO2-eq. The findings in this study advance our knowledge of halocarbon emissions from mobile vehicle air conditioning system in Hong Kong. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. More environment-friendly and safer working gas mixtures for Bakelite RPCs operated in streamer mode

    Science.gov (United States)

    Zhang, Qingmin; Lv, Zhipeng; Lv, Jinge; Zhang, Jiawen; Xu, Jilei; Ning, Zhe

    2017-08-01

    This paper presents experimental results of RPCs performances with different working gas mixtures. Owing to Freon's high global warming potential, its threat to RPCs aging and its large consumption in large particle physics experiments, studies to minimize the concentration of HFC-134A, and even its complete replacement, have been undertaken. In addition, the reduction of iso-butane is also a favorable strategy, due to the flammability level of the gas mixture. Freon-less working gas mixture of Ar/HFC-134A/i-C4H10/CO2=20/0/8/72 was chosen with plateau efficiency of 86.3% and noise rate of 0.61 Hz/cm2. For working gas with lower ratio of Freon, Ar/HFC-134A/i-C4H10/CO2=20/20/8/52 was suggested with plateau efficiency of 91.0% and noise rate of 0.19 Hz/cm2, in which Freon was decreased by 22% compared to the BESIII RPC gas mixture. Furthermore, iso-butane was decreased to 6% with RPC's efficiency of 90% and noise rate of 0.20 Hz/cm2 achieved. Finally, the explanation of RPC's different performances at various working gas mixtures has been validated by the investigation of secondary streamers. This study will be helpful for RPC's application in future large particle physics experiments, in which RPCs can run in streamer mode.

  1. Haptic-Multimodal Flight Control System Update

    Science.gov (United States)

    Goodrich, Kenneth H.; Schutte, Paul C.; Williams, Ralph A.

    2011-01-01

    The rapidly advancing capabilities of autonomous aircraft suggest a future where many of the responsibilities of today s pilot transition to the vehicle, transforming the pilot s job into something akin to driving a car or simply being a passenger. Notionally, this transition will reduce the specialized skills, training, and attention required of the human user while improving safety and performance. However, our experience with highly automated aircraft highlights many challenges to this transition including: lack of automation resilience; adverse human-automation interaction under stress; and the difficulty of developing certification standards and methods of compliance for complex systems performing critical functions traditionally performed by the pilot (e.g., sense and avoid vs. see and avoid). Recognizing these opportunities and realities, researchers at NASA Langley are developing a haptic-multimodal flight control (HFC) system concept that can serve as a bridge between today s state of the art aircraft that are highly automated but have little autonomy and can only be operated safely by highly trained experts (i.e., pilots) to a future in which non-experts (e.g., drivers) can safely and reliably use autonomous aircraft to perform a variety of missions. This paper reviews the motivation and theoretical basis of the HFC system, describes its current state of development, and presents results from two pilot-in-the-loop simulation studies. These preliminary studies suggest the HFC reshapes human-automation interaction in a way well-suited to revolutionary ease-of-use.

  2. Possibilities and limitations of current technologies for quantification of biological extracellular vesicles and synthetic mimics

    Science.gov (United States)

    Maas, Sybren L.N.; de Vrij, Jeroen; van der Vlist, Els J.; Geragousian, Biaina; van Bloois, Louis; Mastrobattista, Enrico; Schiffelers, Raymond M.; Wauben, Marca H.M.; Broekman, Marike L.D.; Nolte-'t Hoen, Esther N.M.

    2015-01-01

    Nano-sized extracelullar vesicles (EVs) released by various cell types play important roles in a plethora of (patho)physiological processes and are increasingly recognized as biomarkers for disease. In addition, engineered EV and EV-inspired liposomes hold great potential as drug delivery systems. Major technologies developed for high-throughput analysis of individual EV include nanoparticle tracking analysis (NTA), tunable resistive pulse sensing (tRPS) and high-resolution flow cytometry (hFC). Currently, there is a need for comparative studies on the available technologies to improve standardization of vesicle analysis in diagnostic or therapeutic settings. We investigated the possibilities, limitations and comparability of NTA, tRPS and hFC for analysis of tumor cell-derived EVs and synthetic mimics (i.e. differently sized liposomes). NTA and tRPS instrument settings were identified that significantly affected the quantification of these particles. Furthermore, we detailed the differences in absolute quantification of EVs and liposomes using the three technologies. This study increases our understanding of possibilities and pitfalls of NTA, tRPS and hFC, which will benefit standardized and large-scale clinical application of (engineered) EVs and EV-mimics in the future. PMID:25555362

  3. Chromosomal aberrations, sister-chromatid exchanges, cells with high frequency of SCE, micronuclei and comet assay parameters in 1, 3-butadiene-exposed workers.

    Science.gov (United States)

    Srám, R J; Rössner, P; Peltonen, K; Podrazilová, K; Mracková, G; Demopoulos, N A; Stephanou, G; Vlachodimitropoulos, D; Darroudi, F; Tates, A D

    1998-11-09

    The association of occupational exposure to 1,3-butadiene (BD) and induction of cytogenetic damage in peripheral lymphocytes was studied in 19 male workers from a monomer production unit and 19 control subjects from a heat production unit. The exposure to BD was measured by passive personal monitors. The following biomarkers were used: chromosomal aberrations (CA), sister chromatid exchanges (SCE), cells with a high frequency of SCE (HFC), micronuclei, comet assay parameters like tail length (TL) and percentage of DNA in tail [T (%)] and polymorphisms of GSTM1 and GSTT1 genotypes. BD exposure with a median value of 0.53 mg/m3 (range: 0.024-23.0) significantly increased (a) the percentage of cells with chromosomal aberrations in exposed vs. control groups (3.11% vs. 2.03%, P<0.01), (b) the frequency of SCE per cell (6.96 vs. 4.87, P<0.001), and (c) the percentage of HFC (19.9% vs. 4.1%, P<0.001). BD exposure had no significant effects on formation of micronuclei and on comet assay parameters. Effect of smoking was observed only for HFC in BD-exposed group. GSTM1 genotype affected chromosomal aberrations in exposed group, while GSTT1 genotype affected chromosomal aberrations in controls. No effect of GSTM1 or GSTT1 genotypes was observed on any other biomarkers used.

  4. The strength of the association between heterozygosity and probability of interannual local recruitment increases with environmental harshness in blue tits.

    Science.gov (United States)

    Ferrer, Esperanza S; García-Navas, Vicente; Sanz, Juan José; Ortego, Joaquín

    2016-12-01

    The extent of inbreeding depression and the magnitude of heterozygosity-fitness correlations (HFC) have been suggested to depend on the environmental context in which they are assayed, but little evidence is available for wild populations. We combine extensive molecular and capture-mark-recapture data from a blue tit (Cyanistes caeruleus) population to (1) analyze the relationship between heterozygosity and probability of interannual adult local recruitment and (2) test whether environmental stress imposed by physiologically suboptimal temperatures and rainfall influence the magnitude of HFC. To address these questions, we used two different arrays of microsatellite markers: 14 loci classified as neutral and 12 loci classified as putatively functional. We found significant relationships between heterozygosity and probability of interannual local recruitment that were most likely explained by variation in genomewide heterozygosity. The strength of the association between heterozygosity and probability of interannual local recruitment was positively associated with annual accumulated precipitation. Annual mean heterozygosity increased over time, which may have resulted from an overall positive selection on heterozygosity over the course of the study period. Finally, neutral and putatively functional loci showed similar trends, but the former had stronger effect sizes and seemed to better reflect genomewide heterozygosity. Overall, our results show that HFC can be context dependent, emphasizing the need to consider the role of environmental heterogeneity as a key factor when exploring the consequences of individual genetic diversity on fitness in natural populations.

  5. Ultrafast laser-triggered emission from hafnium carbide tips

    Science.gov (United States)

    Kealhofer, Catherine; Foreman, Seth M.; Gerlich, Stefan; Kasevich, Mark A.

    2012-07-01

    Electron emission from hafnium carbide (HfC) field emission tips induced by a sub-10-fs, 150-MHz repetition rate Ti:sapphire laser is studied. Two-photon emission is observed at low power with a moderate electric bias field applied to the tips. As the bias field and/or laser power is increased, the average current becomes dominated by thermally enhanced field emission due to laser heating: both the low thermal conductivity of HfC and the laser's high repetition rate can lead to a temperature rise of several hundred Kelvin at the tip apex. The contribution of current from a thermal transient at times shorter than the electron-phonon coupling time is considered in the context of the two-temperature model (TTM). Under the conditions of this experiment, the integrated current from the thermal transient is shown to be negligible in comparison with the two-photon emission. A finite element model of the laser heating and thermal conduction supports these conclusions and is also used to compare the nature of thermal effects in HfC, tungsten, and gold tips.

  6. Substitutes for potent green house gases. HFCs, PFCs and SF{sub 6}. Status report

    Energy Technology Data Exchange (ETDEWEB)

    Pedersen, P.H. [Dansk Teknologisk Institut (Denmark)

    1997-12-31

    CFCs (halogenated chlorofluorocarbons), HCFCs (hydrochlorofluorocarbons), HFCs (hydrofluorocarbons), PFCs (fluorocarbons) and SF{sub 6} (sulphur hexafluoride) are all artificial substances which were not to be found in nature until recently. In 1995 the Danish consumption of HFC substances was approximately 740 tonnes, where the corresponding amount of SF{sub 6} was about 17 tonnes. If the entire amount of these substances was released to to the atmosphere, the resulting impact would correspond to an increased emission of greenhouse gases, corresponding to approximately 1.5 million tonnes of CO{sub 2}. HFC substances would account for 73%, SF{sub 6} with 25% and PFC for 1%. This corresponds to approximately 2.6% of the Danish CO{sub 2} emission (nearly 60 million tonnes per year). This corresponds to about half of the aimed 6% reduction of CO{sub 2} emission attained by introduction of mandatory green taxes on CO{sub 2}. According to experience from the CFC programme it is possible to recover some CFC and send it to controlled destruction. From 1993 to 1996 the refrigeration industry, for instance, has returned a total amount of 163 tonnes of CFC refrigerant through the KMO organization (Koelebranchens Miljoe Ordning). Most of this has been destroyed and a small amount has been purified and recycled afterwards. Similarly, it is likely to believe that some HFC refrigerant will be returned through the KMO organization. (au) 11 refs., also published in Danish

  7. EXPERIMENTAL STUDY ON A NEW ALTERNATIVE REFRIGERANT TO HCFC-22%一种HCFC-22新型替代制冷剂的实验研究

    Institute of Scientific and Technical Information of China (English)

    宣永梅; 陈光明; 陈斌; 王勤

    2004-01-01

    本文提出采用三元混合工质HFC-161/HFC-125/HFC-32作为HCFC-22替代制冷剂.在空气-水热泵实验台上对该工质及HCFC-22、R407C进行对比实验,结果表明,在不改动任何系统部件的前提下,该新型制冷剂的COP值大于HGFC-22主要替代制冷剂R.407C,在较高的进风温度或较低的进水温度下,COP值接近甚至大于HCFC-22.此外,该三元混合物还具有GWF值小、排气温度低、温度滑移小的优点,是HCFC-22一种有前途的替代物.

  8. Foaming characteristics of refigerant/lubricant mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Goswami, D.Y.; Shah, D.O.; Jotshi, C.K.; Bhagwat, S.; Leung, M.; Gregory, A.

    1997-04-01

    The air-conditioning and refrigeration industry has moved to HFC refrigerants which have zero ozone depletion and low global warming potential due to regulations on CFC and HCFC refrigerants and concerns for the environment. The change in refrigerants has prompted the switch from mineral oil and alkylbenzene lubricants to polyolester-based lubricants. This change has also brought about a desire for lubricant, refrigerant and compressor manufacturers to understand the foaming properties of alternative refrigerant/ lubricant mixtures, as well as the mechanisms which affect these properties. The objectives of this investigation are to experimentally determine the foaming absorption and desorption rates of HFC and blended refrigerants in polyolester lubricant and to define the characteristics of the foam formed when the refrigerant leaves the refrigerant/ lubricant mixture after being exposed to a pressure drop. The refrigerants being examined include baseline refrigerants: CFC-12 (R-12) and HCFC-22 (R-22); alternative refrigerants: HFC-32 (R-32), R-125, R-134a, and R-143a; and blended refrigerants: R-404A, R-407C, and R-410A. The baseline refrigerants are tested with ISO 32 (Witco 3GS) and ISO 68 (4GS) mineral oils while the alternative and blended refrigerants are tested with two ISO 68 polyolesters (Witco SL68 and ICI RL68H).

  9. Characterization of RPC operation with new environmental friendly mixtures for LHC application and beyond

    Science.gov (United States)

    Guida, R.; Capeans, M.; Mandelli, B.

    2016-07-01

    The large muon trigger systems based on Resistive Plate Chambers (RPC) at the LHC experiments are currently operated with R134a based mixture. Unfortunately R134a is considered a greenhouse gas with high impact on the enviroment and therefore will be subject to regulations aiming in strongly reducing the available quantity on the market. The immediat effects might be instability on the price and incertitude in the product availability. Alternative gases (HFO-1234yf and HFO-1234ze) have been already identified by industry for specific applications as replacement of R134a. Moreover, HFCs similar to the R134a but with lower global warming potential (GWP) are already available (HFC-245fa, HFC-32, HFC-152a). The present contribution describes the results obtained with RPCs operated with new enviromemtal friendly gases. A particular attention has been addressed to the possibility of maintening the current operation conditions (i.e. currently used applied voltage and front-end electronics) in order to be able to use a new mixture for RPC systems even where the common infrastructure (i.e. high voltage and detector components) cannot be replaced for operation at higher applied voltages.

  10. Aberrant functional connectivity in Papez circuit correlates with memory performance in cognitively intact middle-aged APOE4 carriers.

    Science.gov (United States)

    Li, Wenjun; Antuono, Piero G; Xie, Chunming; Chen, Gang; Jones, Jennifer L; Ward, B Douglas; Singh, Suraj P; Franczak, Malgorzata B; Goveas, Joseph S; Li, Shi-Jiang

    2014-08-01

    The main objective of this study is to detect the early changes in resting-state Papez circuit functional connectivity using the hippocampus as the seed, and to determine the associations between altered functional connectivity (FC) and the episodic memory performance in cognitively intact middle-aged apolipoprotein E4 (APOE4) carriers who are at risk of Alzheimer's disease (AD). Forty-six cognitively intact, middle-aged participants, including 20 APOE4 carriers and 26 age-, sex-, and education-matched noncarriers were studied. The resting-state FC of the hippocampus (HFC) was compared between APOE4 carriers and noncarriers. APOE4 carriers showed significantly decreased FC in brain areas that involve learning and memory functions, including the frontal, cingulate, thalamus and basal ganglia regions. Multiple linear regression analysis showed significant correlations between HFC and the episodic memory performance. Conjunction analysis between neural correlates of memory and altered HFC showed the overlapping regions, especially the subcortical regions such as thalamus, caudate nucleus, and cingulate cortices involved in the Papez circuit. Thus, changes in connectivity in the Papez circuit may be used as an early risk detection for AD.

  11. The use of a radiotelemetric ruminal bolus to detect body temperature changes in lactating dairy cattle.

    Science.gov (United States)

    Alzahal, O; Alzahal, H; Steele, M A; Van Schaik, M; Kyriazakis, I; Duffield, T F; McBride, B W

    2011-07-01

    The objective of this study was to validate the efficacy of a radiotelemetric bolus (RTB) to detect changes in ruminal temperature resulting from (1) systemic illnesses that are associated with febrile responses and (2) subacute ruminal acidosis (SARA). Eight rumen-fistulated, lactating Holstein cows (586±37 kg of body weight, 106±18 d in milk) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement. Each period consisted of 21 d. The factors were 2 diets, a moderate forage:concentrate [MFC; 52:48; % of dry matter (DM)] or a high forage:concentrate (HFC; 65:35, % of DM) total mixed ration, and a challenge with a single intramammary injection of lipopolysaccharide (LPS; 100 μg derived from Escherichia coli 0111:B4) or no LPS (sterile saline). Thus, the 4 resulting treatments were (1) MFC with LPS challenge, (2) MFC with saline, (3) HFC with LPS challenge, and (4) HFC with saline. Cows were fed at 0800 and 1400 h daily. Cows received the intramammary injections at 0900 h of d 21. Ruminal pH and ruminal temperature were also measured on d 21 every minute via an indwelling logging system that resided in the ventral sac of the rumen and via a radiotelemetric bolus that resided in the reticulum. Vaginal temperature was also recorded every minute via temperature loggers. Prior to LPS injection, the duration of rumen pH below 5.6 (indicative of SARA) was higher in cows receiving MFC than cows receiving HFC (148±24 and 62±24 min/d, respectively). The temperature measured at the same time via RTB was higher for MFC than HFC cows (167±21 vs. 104 vs. 21 min/d above 38.8°C, respectively). The following day, cows challenged with LPS showed signs of mastitis within the injected quarters, depressed DM intake, decreased milk yield, and a peak vaginal temperature of 41.3±0.1°C 5.5h after the LPS injection. The RTB system successfully detected a fever response parallel to that measured by the vaginal loggers but temperature peak detected by

  12. Medium-chain triglyceride ameliorates insulin resistance and inflammation in high fat diet-induced obese mice.

    Science.gov (United States)

    Geng, Shanshan; Zhu, Weiwei; Xie, Chunfeng; Li, Xiaoting; Wu, Jieshu; Liang, Zhaofeng; Xie, Wei; Zhu, Jianyun; Huang, Cong; Zhu, Mingming; Wu, Rui; Zhong, Caiyun

    2016-04-01

    The aim of the present study was to investigate the in vivo effects of dietary medium-chain triglyceride (MCT) on inflammation and insulin resistance as well as the underlying potential molecular mechanisms in high fat diet-induced obese mice. Male C57BL/6J mice (n = 24) were fed one of the following three diets for a period of 12 weeks: (1) a modified AIN-76 diet with 5 % corn oil (normal diet); (2) a high-fat control diet (17 % w/w lard and 3 % w/w corn oil, HFC); (3) an isocaloric high-fat diet supplemented with MCT (17 % w/w MCT and 3 % w/w corn oil, HF-MCT). Glucose metabolism was evaluated by fasting blood glucose levels and intraperitoneal glucose tolerance test. Insulin sensitivity was evaluated by fasting serum insulin levels and the index of homeostasis model assessment-insulin resistance. The levels of serum interleukin-6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor-α were measured by ELISA, and hepatic activation of nuclear factor κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways was determined using western blot analysis. Compared to HFC diet, consumption of HF-MCT did not induce body weight gain and white adipose tissue accumulation in mice. HFC-induced increases in serum fasting glucose and insulin levels as well as glucose intolerance were prevented by HF-MCT diet. Meanwhile, HF-MCT resulted in significantly lower serum IL-6 level and higher IL-10 level, and lower expression levels of inducible nitric oxide synthase and cyclooxygenase-2 protein in liver tissues when compared to HFC. In addition, HF-MCT attenuated HFC-triggered hepatic activation of NF-κB and p38 MAPK. Our study demonstrated that MCT was efficacious in suppressing body fat accumulation, insulin resistance, inflammatory response, and NF-κB and p38 MAPK activation in high fat diet-fed mice. These data suggest that MCT may exert beneficial effects against high fat diet-induced insulin resistance and inflammation.

  13. The herbal formula KH-204 is protective against erectile dysfunction by minimizing oxidative stress and improving lipid profiles in a rat model of erectile dysfunction induced by hypercholesterolaemia.

    Science.gov (United States)

    Jang, Hoon; Bae, Woong Jin; Kim, Su Jin; Cho, Hyuk Jin; Yuk, Seung Mo; Han, Dong Seok; Youn, Chang Shik; Kwon, Eun Bi; Hwang, Sung Yeoun; Kim, Sae Woong

    2017-02-24

    Hypercholesterolaemia (HC) is a major risk factor for ischemic heart disease and is also known to be a risk factor for erectile dysfunction (ED). ED caused by HC is thought to be related to HC-induced oxidative stress damage in the vascular endothelium and erectile tissue. KH-204 is an herbal formula with a strong antioxidant effect. We evaluated the effects of KH-204 on erectile function in a rat model of HC-induced ED. Male Sprague-Dawley rats (6 weeks old) were divided into normal control, high-fat and cholesterol diet (HFC), and HFC with KH-204 treatment (HFC + KH) groups (n = 12 each). Normal control group rats were fed normal chow diet. HFC and HFC + KH group rats were fed high-fat and cholesterol diets and treated with or without daily oral doses of KH-204 for 12 weeks. Subsequently, intracavernous pressure (ICP) and mean arterial pressure (MAP) were measured, and lipid profiles, expression of endothelial (eNOS) and neuronal (nNOS) nitric oxide synthase, oxidative stress (8-hydroxy-2-deoxyguanosine), and ratio of smooth muscle cells and collagen fibres were evaluated in the serum and corpora tissue. Compared to the HFC group, the HFC + KH group showed statistically significant increases in peak ICP and ICP/MAP ratio, expression of eNOS and nNOS, and ratio of smooth muscle cells and collagen fibres (p < 0.05). The HFC + KH group also showed statistically significant decreases in oxidative stress (p < 0.05). Further the lipid profiles of this group were ameliorated compared to those of the HFC group (p < 0.05). The current study shows that the antioxidant and hypolipidemic effects of KH-204 are effective in ameliorating ED by restoring endothelial dysfunction and suggests that KH-204 may be a potential therapeutic agent for ED by correcting the fundamental cause of ED.

  14. 硫酸镉与α-萘黄酮对斑马鱼发育的个体毒性与联合毒性研究%Individual and joint toxic effects of cadmium sulfate andα-naphthoflavone on the development of zebrafish embryo

    Institute of Scientific and Technical Information of China (English)

    Jian YIN; Jian-ming YANG; Feng ZHANG; Peng MIAO; Ying LIN; Ming-li CHEN

    2014-01-01

    研究目的:研究硫酸镉与α-萘黄酮对斑马鱼发育的个体毒性与联合毒性,并探讨其中的联合毒性机制。  创新要点:首次对硫酸镉与α-萘黄酮的联合毒性进行了研究,并探索了氧化应激、ATP结合盒式(ABC)转运蛋白及细胞色素P450蛋白(CYP)1A在化合物联合毒性中的作用。  研究方法:在不同时间点,依据形态学指标检测硫酸镉与α-萘黄酮单独使用与联合使用时对斑马鱼胚胎的致死与致畸性毒性。取样品,采用试剂盒检测不同处理状态下斑马鱼胚胎中谷胱甘肽(GSH)、超氧化物歧化酶(SOD)及丙二醛(MDA)三个氧化还原指标的改变,聚合酶链式反应(PCR)检测样品中多药耐药蛋白(mrp)1及cyp1a基因表达水平的改变。  重要结论:硫酸镉与α-萘黄酮的联用能够产生远大于个体且显著增强各自的毒性,而这种增强作用机理在于氧化应激压力的产生,以及两者合用下mrp1及cyp1a基因表达水平的改变。%This paper aims to evaluate the individual and joint toxicities of cadmium sulfate (CdSO4) andα-naphthoflavone (ANF) in zebrafish embryos. As a result, CdSO4 caused both lethal and sub-lethal effects, such as 24 h post-fertilization (hpf) death and 72 hpf delayed hatching. However, ANF only caused sub-lethal effects, including 48 hpf cardiac edema and 72 hpf delayed hatching. Taking 24 hpf death and 48 hpf cardiac edema as endpoints, the toxicities of CdSO4 and ANF were significantly enhanced by each other. Consistently, both CdSO4 and ANF caused significant oxidative stress, including decreases in the reduced glutathione (GSH) level, inhibition of superoxide dis-mutase (SOD) activity, as wel as increases in malondialdehyde (MDA) content in zebrafish embryos, but these mix-tures produced much more significant alterations on the biomarkers. Co-treatment of CdSO4 and ANF significantly down-regulated the mRNA level of

  15. Simulation of the electrically stimulated cochlear neuron: modeling adaptation to trains of electric pulses.

    Science.gov (United States)

    Woo, Jihwan; Miller, Charles A; Abbas, Paul J

    2009-05-01

    The Hodgkin-Huxley (HH) model does not simulate the significant changes in auditory nerve fiber (ANF) responses to sustained stimulation that are associated with neural adaptation. Given that the electric stimuli used by cochlear prostheses can result in adapted responses, a computational model incorporating an adaptation process is warranted if such models are to remain relevant and contribute to related research efforts. In this paper, we describe the development of a modified HH single-node model that includes potassium ion ( K(+)) concentration changes in response to each action potential. This activity-related change results in an altered resting potential, and hence, excitability. Our implementation of K(+)-related changes uses a phenomenological approach based upon K(+) accumulation and dissipation time constants. Modeled spike times were computed using repeated presentations of modeled pulse-train stimuli. Spike-rate adaptation was characterized by rate decrements and time constants and compared against ANF data from animal experiments. Responses to relatively low (250 pulse/s) and high rate (5000 pulse/s) trains were evaluated and the novel adaptation model results were compared against model results obtained without the adaptation mechanism. In addition to spike-rate changes, jitter and spike intervals were evaluated and found to change with the addition of modeled adaptation. These results provide one means of incorporating a heretofore neglected (although important) aspect of ANF responses to electric stimuli. Future studies could include evaluation of alternative versions of the adaptation model elements and broadening the model to simulate a complete axon, and eventually, a spatially realistic model of the electrically stimulated nerve within extracochlear tissues.

  16. Multiple amino acid sequence alignment nitrogenase component 1: insights into phylogenetics and structure-function relationships.

    Science.gov (United States)

    Howard, James B; Kechris, Katerina J; Rees, Douglas C; Glazer, Alexander N

    2013-01-01

    Amino acid residues critical for a protein's structure-function are retained by natural selection and these residues are identified by the level of variance in co-aligned homologous protein sequences. The relevant residues in the nitrogen fixation Component 1 α- and β-subunits were identified by the alignment of 95 protein sequences. Proteins were included from species encompassing multiple microbial phyla and diverse ecological niches as well as the nitrogen fixation genotypes, anf, nif, and vnf, which encode proteins associated with cofactors differing at one metal site. After adjusting for differences in sequence length, insertions, and deletions, the remaining >85% of the sequence co-aligned the subunits from the three genotypes. Six Groups, designated Anf, Vnf , and Nif I-IV, were assigned based upon genetic origin, sequence adjustments, and conserved residues. Both subunits subdivided into the same groups. Invariant and single variant residues were identified and were defined as "core" for nitrogenase function. Three species in Group Nif-III, Candidatus Desulforudis audaxviator, Desulfotomaculum kuznetsovii, and Thermodesulfatator indicus, were found to have a seleno-cysteine that replaces one cysteinyl ligand of the 8Fe:7S, P-cluster. Subsets of invariant residues, limited to individual groups, were identified; these unique residues help identify the gene of origin (anf, nif, or vnf) yet should not be considered diagnostic of the metal content of associated cofactors. Fourteen of the 19 residues that compose the cofactor pocket are invariant or single variant; the other five residues are highly variable but do not correlate with the putative metal content of the cofactor. The variable residues are clustered on one side of the cofactor, away from other functional centers in the three dimensional structure. Many of the invariant and single variant residues were not previously recognized as potentially critical and their identification provides the bases for

  17. Multiple amino acid sequence alignment nitrogenase component 1: insights into phylogenetics and structure-function relationships.

    Directory of Open Access Journals (Sweden)

    James B Howard

    Full Text Available Amino acid residues critical for a protein's structure-function are retained by natural selection and these residues are identified by the level of variance in co-aligned homologous protein sequences. The relevant residues in the nitrogen fixation Component 1 α- and β-subunits were identified by the alignment of 95 protein sequences. Proteins were included from species encompassing multiple microbial phyla and diverse ecological niches as well as the nitrogen fixation genotypes, anf, nif, and vnf, which encode proteins associated with cofactors differing at one metal site. After adjusting for differences in sequence length, insertions, and deletions, the remaining >85% of the sequence co-aligned the subunits from the three genotypes. Six Groups, designated Anf, Vnf , and Nif I-IV, were assigned based upon genetic origin, sequence adjustments, and conserved residues. Both subunits subdivided into the same groups. Invariant and single variant residues were identified and were defined as "core" for nitrogenase function. Three species in Group Nif-III, Candidatus Desulforudis audaxviator, Desulfotomaculum kuznetsovii, and Thermodesulfatator indicus, were found to have a seleno-cysteine that replaces one cysteinyl ligand of the 8Fe:7S, P-cluster. Subsets of invariant residues, limited to individual groups, were identified; these unique residues help identify the gene of origin (anf, nif, or vnf yet should not be considered diagnostic of the metal content of associated cofactors. Fourteen of the 19 residues that compose the cofactor pocket are invariant or single variant; the other five residues are highly variable but do not correlate with the putative metal content of the cofactor. The variable residues are clustered on one side of the cofactor, away from other functional centers in the three dimensional structure. Many of the invariant and single variant residues were not previously recognized as potentially critical and their identification

  18. Neuropsychologische und psychiatrische Komorbiditäten bei Epilepsien

    Directory of Open Access Journals (Sweden)

    Lehner-Baumgartner E

    2009-01-01

    Full Text Available Neuropsychologische Beeinträchtigungen stellen ein gravierendes Problem für viele Epilepsiepatienten dar und werden im Wesentlichen durch die 3 folgenden Faktoren verursacht und beeinflusst: (1 Morphologische Faktoren – Lokalisation und Art der epileptogenen Läsion. Zudem können umschriebene Läsionen auch zu funktionellen Beeinträchtigungen in von der Läsion entfernten Hirnregionen führen, was durch eine Störung von funktionellen Netzwerken erklärt werden kann. (2 Klinische und demographische Faktoren (Alter zu Erkrankungsbeginn, Erkrankungsdauer, Anfallsfrequenz und -schwere, Geschlecht. (3 Funktionelle Faktoren (antikonvulsive Medikation, allfällige psychiatrische Komorbiditäten, Effekte von Anfällen und interiktale epileptiforme Entladungen. Psychiatrische Erkrankungen (Depressionen, Psychosen und Angststörungen treten bei Epilepsiepatienten signifikant häufiger auf als in der Allgemeinbevölkerung und als bei anderen chronischen Erkrankungen. Psychiatrische Störungen können entweder in einer fixen zeitlichen Beziehung zu den Anfällen auftreten (präiktale, iktale und postiktale psychiatrische Störungen oder sich unabhängig vom Auftreten der Anfälle manifestieren (interiktale psychiatrische Störung. Die Depression stellt die häufigste psychiatrische Begleiterkrankung bei Epilepsie dar, zudem ist eine Depression ein Risikofaktor für das Neu- Auftreten einer Epilepsie. Diese bidirektionale Beziehung könnte durch gemeinsame Pathomechanismen beider Erkrankungen erklärt werden. Obwohl das Vorliegen und der Schweregrad einer Depression die wichtigsten Prädiktoren für die Lebensqualität bei Epilepsiepatienten darstellen, werden Depressionen bei Epilepsiepatienten unterdiagnostiziert und unterbehandelt. Eine psychopharmakologische Behandlung sollte bei Vorliegen einer Begleitdepression unverzüglich initiiert werden, das epileptogene Potenzial von Antidepressiva stellt dabei ein vernachlässigbares Risiko dar.

  19. Endokrinologie in der Lebensmitte: Die Perimenopause.

    Directory of Open Access Journals (Sweden)

    Seifert-Klauss V

    2012-01-01

    Full Text Available Anhand dreier Kasuistiken aus der gynäkologischen Hormonsprechstunde werden beispielhaft besondere Situationen und eine darauf individuell abgestimmte Hormontherapie während der Perimenopause vorgestellt. Der erste Fall beschreibt eine 47-jährige Patientin mit ausgeprägter perimenopausaler Symptomatik und Östrogen-Dominanz. Die Dokumentation über 5 Jahre illustriert die Probleme, die perimenopausal durch die endogene Überstimulation der Ovarien entstehen können. Über die Unvorhersehbarkeit der perimenopausalen Hormonschwankungen, die sich in Brustspannen und Wassereinlagerungen bei hohen Östrogenspiegeln sowie Hitzewallungen und Schweißausbrüchen bei Abfall der endogenen Östrogenspiegel äußern, sollten Patientinnen aufgeklärt werden. Durch eine zyklische Gestagensubstitution kann bei Östrogendominanz unter Umständen mehr Beschwerdeerleichterung erreicht werden als durch eine hochdosierte Östrogentherapie. Fall 2 stellt eine 47-jährige Patientin mit Epilepsie vor, deren perimenopausal bedingte Hormonschwankungen zu vermehrten Anfällen führen. Hier gilt es abzuklären, ob die Anfälle durch stark erhöhte Estradiolspiegel, die zum Ende des Zyklus hin abfallen, begünstigt werden oder aber die Art und Entstehungsgeschichte der Epilepsie nicht auf eine andere Interaktion zwischen Perimenopause und Anfällen hindeuten. In der dritten Kasuistik geht es um eine 54- jährige Patientin mit Morbus Basedow, bei der die ausgeprägte Interaktion zwischen der Schilddrüseneinstellung und den steigenden FSH-, LHsowie unvorhersehbar wechselnden Östrogenspiegeln aufgezeigt und eine individuelle symptombezogene Hormontherapie erforderlich ist.

  20. Retinoid X receptor alpha represses GATA-4-mediated transcription via a retinoid-dependent interaction with the cardiac-enriched repressor FOG-2.

    Science.gov (United States)

    Clabby, Martha L; Robison, Trevor A; Quigley, Heather F; Wilson, David B; Kelly, Daniel P

    2003-02-21

    Dietary vitamin A and its derivatives, retinoids, regulate cardiac growth and development. To delineate mechanisms involved in retinoid-mediated control of cardiac gene expression, the regulatory effects of the retinoid X receptor alpha (RXR alpha) on atrial naturietic factor (ANF) gene transcription was investigated. The transcriptional activity of an ANF promoter-reporter in rat neonatal ventricular myocytes was repressed by RXR alpha in the presence of 9-cis-RA and by the constitutively active mutant RXR alpha F318A indicating that liganded RXR confers the regulatory effect. The RXR alpha-mediated repression mapped to the proximal 147 bp of the rat ANF promoter, a region lacking a consensus retinoid response element but containing several known cardiogenic cis elements including a well characterized GATA response element. Glutathione S-transferase "pull-down" assays revealed that RXR alpha interacts directly with GATA-4, in a ligand-independent manner, via the DNA binding domain of RXR alpha and the second zinc finger of GATA-4. Liganded RXR alpha repressed the activity of a heterologous promoter-reporter construct containing GATA-response element recognition sites in cardiac myocytes but not in several other cell types, suggesting that additional cardiac-enriched factors participate in the repression complex. Co-transfection of liganded RXR alpha and the known cardiac-enriched GATA-4 repressor, FOG-2, resulted in additive repression of GATA-4 activity in ventricular myocytes. In addition, RXR alpha was found to bind FOG-2, in a 9-cis-RA-dependent manner. These data reveal a novel mechanism by which retinoids regulate cardiogenic gene expression through direct interaction with GATA-4 and its co-repressor, FOG-2.