WorldWideScience

Sample records for cassegrainian concentrators

  1. Coma of modified Gregorian and Cassegrainian mirror systems

    Science.gov (United States)

    Jones, R. T.

    1976-01-01

    The equivalence of the classical Newtonian, Cassegrainian, and Gregorian mirror systems with respect to the first two Seidel aberrations is rederived by means of a simple congruence. The effects of arbitrary small modifications of the two mirror systems are then studied and general formulas are derived for the effects of such modifications on the spherical aberration and coma. Spherical aberration is corrected to the third order if the amount of glass removed from one surface is replaced at the corresponding zone of the other surface. Modifications in which one surface is made spherical while the other is adjusted to eliminate spherical aberration result in large increases of coma for systems having the usual amplifying ratios.

  2. Effects of illumination functions on the computation of gravity-dependent signal path variation models in primary focus and Cassegrainian VLBI telescopes

    Science.gov (United States)

    Abbondanza, Claudio; Sarti, Pierguido

    2010-08-01

    This paper sets the rules for an optimal definition of precise signal path variation (SPV) models, revising and highlighting the deficiencies in the calculations adopted in previous studies and improving the computational approach. Hence, the linear coefficients that define the SPV model are rigorously determined. The equations that are presented depend on the dimensions and the focal lengths of the telescopes as well as on the feed illumination taper. They hold for any primary focus or Cassegrainian very long baseline interferometry (VLBI) telescope. Earlier investigations usually determined the SPV models assuming a uniform illumination of the telescope mirrors. We prove this hypothesis to be over-simplistic by comparing results derived adopting (a) uniform, (b) Gaussian and (c) binomial illumination functions. Numerical computations are developed for AZ-EL mount, 32 m Medicina and Noto (Italy) VLBI telescopes, these latter being the only telescopes which possess thorough information on gravity-dependent deformation patterns. Particularly, assuming a Gaussian illumination function, the SPV in primary focus over the elevation range [0°, 90°] is 10.1 and 7.2 mm, for Medicina and Noto, respectively. With uniform illumination function the maximal path variation for Medicina is 17.6 and 12.7 mm for Noto, thus highlighting the strong dependency on the choice of the illumination function. According to our findings, a revised SPV model is released for Medicina and a model for Noto is presented here for the first time. Currently, no other VLBI telescope possesses SPV models capable of correcting gravity-dependent observation biases.

  3. Parabolic concentrating collector: a tutorial

    Energy Technology Data Exchange (ETDEWEB)

    Truscello, V.C.

    1979-02-15

    A tutorial overview of point-focusing parabolic collectors is presented. Optical and thermal characteristics of such collectors are discussed. Data representing typical achievable collector efficiencies are presented and the importance of balancing collector cost with concentrator quality is argued through the development of a figure of merit for the collector. The impact of receiver temperature on performance is assessed and the general observation made that temperatures much in excess of 1500 to 2000/sup 0/F can actually result in decreased performance. Various types of two-axis tracking collectors are described, including the standard parabolic deep dish, Cassegrainian and Fresnel, as well as two forms of fixed mirrors with articulating receivers. The present DOE program to develop these devices is briefly discussed, as are present and projected costs for these collectors. Pricing information is presented for the only known commercial design available on the open market.

  4. Near-optimum design of GaAs-based concentrator space solar cells for 80 C operation

    Science.gov (United States)

    Goradia, C.; Ghalla-Goradia, M.; Curtis, H.

    Using a detailed computer simulation model and reasonable values of optical, geometrical and material parameters from current published literature, parameter optimization studies were performed on two cell geometries, namely, the circular geometry for a Cassegrainian concentrator with 100 AM0, 80 C operation and the rectangular geometry for a venetian blind concentrator with 20 AM0, 80 C operation. For each cell geometry, three cell configurations were considered: p/n AlGaAs/GaAs; n/p AlGaAs/GaAs; and, n/p GaAs shallow homojunction. The studies show the possibility of designing GaAs-based space solar cells with beginning-of-life efficiencies exceeding 22 percent at 20 to 100 AM0, 80 C and probable efficiency degradation of less than 15 percent after a 70 percent reduction in diffusion length in each cell region.

  5. High-performance deployable structures for the support of high-concentration ratio solar array modules

    Science.gov (United States)

    Mobrem, M.

    1985-01-01

    A study conducted on high-performance deployable structures for the support of high-concentration ratio solar array modules is discussed. Serious consideration is being given to the use of high-concentration ratio solar array modules or applications such as space stations. These concentrator solar array designs offer the potential of reduced cost, reduced electrical complexity, higher power per unit area, and improved survivability. Arrays of concentrators, such as the miniaturized Cassegrainian concentrator modules, present a serious challenge to the structural design because their mass per unit area (5.7 kg/square meters) is higher than that of flexible solar array blankets, and the requirement for accurate orientation towards the Sun (plus or minus 0.5 degree) requires structures with improved accuracy potentials. In addition, use on a space station requires relatively high structural natural frequencies to avoid deleterious interactions with control systems and other large structural components. The objective here is to identify and evaluate conceptual designs of structures suitable for deploying and accurately supporting high-concentration ratio solar array modules.

  6. Concentration device

    DEFF Research Database (Denmark)

    2013-01-01

    A concentration device (2) for filter filtration concentration of particles (4) from a volume of a fluid (6). The concentration device (2) comprises a filter (8) configured to filter particles (4) of a predefined size in the volume of the fluid (6). The concentration device (2) comprises...

  7. Concentrated Ownership

    DEFF Research Database (Denmark)

    Rose, Caspar

    2014-01-01

    This entry summarizes the main theoretical contributions and empirical findings in relation to concentrated ownership from a law and economics perspective. The various forms of concentrated ownership are described as well as analyzed from the perspective of the legal protection of investors......, especially minority shareholders. Concentrated ownership is associated with benefits and costs. Concentrated ownership may reduce agency costs by increased monitoring of top management. However, concentrated ownership may also provide dominating owners with private benefits of control....

  8. Concentrator Photovoltaics

    CERN Document Server

    Luque, Antonio L

    2007-01-01

    Photovoltaic solar-energy conversion is one of the most promising technologies for generating renewable energy, and conversion of concentrated sunlight can lead to reduced cost for solar electricity. In fact, photovoltaic conversion of concentrated sunlight insures an efficient and cost-effective sustainable power resource. This book gives an overview of all components, e.g. cells, concentrators, modules and systems, for systems of concentrator photovoltaics. The authors report on significant results related to design, technology, and applications, and also cover the fundamental physics and market considerations. Specific contributions include: theory and practice of sunlight concentrators; an overview of concentrator PV activities; a description of concentrator solar cells; design and technology of modules and systems; manufacturing aspects; and a market study.

  9. Concentrating Radioactivity

    Science.gov (United States)

    Herrmann, Richard A.

    1974-01-01

    By concentrating radioactivity contained on luminous dials, a teacher can make a high reading source for classroom experiments on radiation. The preparation of the source and its uses are described. (DT)

  10. Photovoltaic concentrator module technology

    Science.gov (United States)

    Richards, Elizabeth H.; Chamberlin, Jay L.; Boes, Eldon C.

    Significant developments in the development of photovoltaic (PV) concentrator technology are described. Concentrator cell research, advances in PV concentrator cell technology, and PV concentrator module development are described. Reliability issues currently of concern, including the applicability of wet insulation resistance tests to concentrator modules, correlation of accelerated thermal cycling tests with life expectancy in the field, and the importance of quality assurance during manufacture, are discussed. Two PV concentrator power systems installed in 1989 are discussed. A PV concentrator initiative program established by the DOE is given, and the results of the latest cost study are presented.

  11. RESTAURANT CONCENTRATION IN LOUISIANA

    OpenAIRE

    Schupp, Alvin R.; Dennis, Winston

    1990-01-01

    Growth of the franchise restaurant industry and merger activity among restaurants raise questions concerning concentration in the Louisiana restaurant industry. Firm employment data from the Louisiana Department of Labor for selected urban and rural parishes for 1975-86 and the concentration ratio, herfindahl index and the entropy measure were used for these concentration estimates. Concentration was, in general, low in urban parishes and higher in rural parishes. Concentration decreased from...

  12. Highly concentrating Fresnel lenses

    International Nuclear Information System (INIS)

    A new type of concave Fresnel lens capable of concentrating solar radiation very near the ultimate concentration limit is considered. The differential equations that describe the lens are solved to provide computed solutions which are then checked by ray tracing techniques. The performance (efficiency and concentration) of the lens is investigated and compared to that of a flat Fresnel lens, showing that the new lens is preferable for concentrating solar radiation. (author)

  13. Solar cell concentrating system

    International Nuclear Information System (INIS)

    This study reviews fabrication techniques and testing facilities for different solar cells under concentration which have been developed and tested. It is also aimed to examine solar energy concentrators which are prospective candidates for photovoltaic concentrator systems. This may provide an impetus to the scientists working in the area of solar cell technology

  14. Automated solvent concentrator

    Science.gov (United States)

    Griffith, J. S.; Stuart, J. L.

    1976-01-01

    Designed for automated drug identification system (AUDRI), device increases concentration by 100. Sample is first filtered, removing particulate contaminants and reducing water content of sample. Sample is extracted from filtered residue by specific solvent. Concentrator provides input material to analysis subsystem.

  15. Concentrating solar power

    International Nuclear Information System (INIS)

    This annual evaluation is a synthesis of works published in 2006. Comparisons are presented between the wind power performances and European Commission White Paper and Biomass action plan objectives. After having been blocked for a long time in its development, the concentrating solar power sector is undergoing a full revival today due to the falling costs, more effective technologies and policies sensitive to environmental questions. The USA concentrates today practically all of the installed concentrating solar power capacity in the world. But the sector is now also being carried by Spain. (A.L.B.)

  16. Concentrating photovoltaic solar panel

    Science.gov (United States)

    Cashion, Steven A; Bowser, Michael R; Farrelly, Mark B; Hines, Braden E; Holmes, Howard C; Johnson, Jr., Richard L; Russell, Richard J; Turk, Michael F

    2014-04-15

    The present invention relates to photovoltaic power systems, photovoltaic concentrator modules, and related methods. In particular, the present invention features concentrator modules having interior points of attachment for an articulating mechanism and/or an articulating mechanism that has a unique arrangement of chassis members so as to isolate bending, etc. from being transferred among the chassis members. The present invention also features adjustable solar panel mounting features and/or mounting features with two or more degrees of freedom. The present invention also features a mechanical fastener for secondary optics in a concentrator module.

  17. Concentration of Hydrogen Peroxide

    Science.gov (United States)

    Parrish, Clyde F. (Inventor)

    2006-01-01

    Methods for concentrating hydrogen peroxide solutions have been described. The methods utilize a polymeric membrane separating a hydrogen peroxide solution from a sweep gas or permeate. The membrane is selective to the permeability of water over the permeability of hydrogen peroxide, thereby facilitating the concentration of the hydrogen peroxide solution through the transport of water through the membrane to the permeate. By utilizing methods in accordance with the invention, hydrogen peroxide solutions of up to 85% by volume or higher may be generated at a point of use without storing substantial quantities of the highly concentrated solutions and without requiring temperatures that would produce explosive mixtures of hydrogen peroxide vapors.

  18. Concentration and content.

    Science.gov (United States)

    Fuentes-Arderiu, Xavier

    2013-01-01

    One of the more frequent activities in health sciences is the measurement of biological quantities. Frequently, when reading biomedical books and journals some confusion on the metrological meaning of biological quantities related to the concepts 'concentration' and 'content' may be observed. Classically, a concentration is an amount of any type per volume of liquid or gas system, whereas content is an amount of any type per mass of liquid or gas or solid system. However the concepts 'concentration' and 'content' alone are still ambiguous because, depending on the type of amount of the component (analyte) per volume or mass of a system, there are different types of concentrations and contents. This article attempts to give a clarification of these concepts, mainly based on international recommendations about nomenclature and terminology of metrology, chemistry and clinical laboratory sciences. PMID:23894859

  19. Censored correlated cytokine concentrations

    DEFF Research Database (Denmark)

    Andersen, Andreas; Benn, Christine Stabell; Jørgensen, Mathias J;

    2013-01-01

    Interest in cytokines as markers for the function of the immune system is increasing. Methods quantifying cytokine concentrations are often subject to detection limits, which lead to non-detectable observations and censored distributions. When distributions are skewed, geometric mean ratios (GMRs......) can be used to describe the relative concentration between two cytokines, and the GMR ratio (GMRR) can be used to compare two groups. The problem is how to estimate GMRRs from censored distributions.We evaluated methods, including simple deletion and substitution, in simulated and real data. One...... method applies Tobit directly to the censored difference between the two cytokine log-concentrations (Diff). However, censoring is correlated to the outcome and is therefore not independent. The correlation increases as the correlation between the two log-concentrations decreases. We propose a Tobit...

  20. Concentrator silicon cell research

    Energy Technology Data Exchange (ETDEWEB)

    Green, M.A.; Wenham, S.R.; Zhang, F.; Zhao, J.; Wang, A. [New South Wales Univ., Kensington (Australia). Solar Photovoltaic Lab.

    1992-04-01

    This project continued the developments of high-efficiency silicon concentrator solar cells with the goal of achieving a cell efficiency in the 26 to 27 percent range at a concentration level of 150 suns of greater. The target efficiency was achieved with the new PERL (passivated emitter, rear locally diffused) cell structure, but only at low concentration levels around 20 suns. The PERL structure combines oxide passivation of both top and rear surfaces of the cells with small area contact to heavily doped regions on the top and rear surfaces. Efficiency in the 22 to 23 percent range was also demonstrated for large-area concentrator cells fabricated with the buried contact solar cell processing sequence, either when combined with prismatic covers or with other innovative approaches to reduce top contact shadowing. 19 refs.

  1. Rheology of concentrated biomass

    Science.gov (United States)

    Samaniuk, J. R.; Wang, J.; Root, T. W.; Scott, C. T.; Klingenberg, D. J.

    2011-12-01

    Economic processing of lignocellulosic biomass requires handling the biomass at high solids concentration. This creates challenges because concentrated biomass behaves as a Bingham-like material with large yield stresses. Here we employ torque rheometry to measure the rheological properties of concentrated lignocellulosic biomass (corn stover). Yield stresses obtained using torque rheometry agree with those obtained using other rheometric methods, but torque rheometry can be used at much larger solids concentration (weight fractions of insoluble solids greater than 0.2). Yield stresses decrease with severity of hydrolysis, decrease when water-soluble polymers are added (for nonhydrolyzed biomass), and increase with particle length. Experimental results are qualitatively consistent with those obtained from particle-level simulations.

  2. Workplace Concentration of Immigrants

    OpenAIRE

    Monica I. Garcia-Perez; Fredrik Andersson; John Haltiwanger; Fredrik Kristin McCue; Seth Sanders

    2014-01-01

    To what extent do immigrants and the native-born work in separate workplaces? Do worker and firm characteristics explain the degree of workplace concentration? We explore these questions using a matched employer-employee database that extensively covers employers in selected MSAs. We find that immigrants are much more likely to have immigrant coworkers than are natives, and are particularly likely to work with their compatriots. We find much higher levels of concentration for small businesses...

  3. Test bed concentrator mirrors

    Science.gov (United States)

    Argoud, M. J.

    1980-05-01

    The test bed concentrator (TBC) was des point focusing distributed receiver (PFDR) systems. The reflective surface of the concentrator was fabricated using mirror facet designs and techniques. The facets are made by bonding mirrored glass to spherically-conducted substrates. Several aspects of earlier work were reevaluated for application to the TBC: optimum glass block size, material selection, environmental test, optical characteristics, and reliability. A detailed explanation of tooling, substrate preparation, testing techniques, and mirror assembly is presented.

  4. FK concentrator outdoor measurements

    OpenAIRE

    Hernández Sanz, Maikel; Vilaplana, J.; Benitez Gimenez, Pablo; Mohedano,, Rubén; Zamora Herranz, Pablo; Miñano Dominguez, Juan Carlos; Mendes Lopes, Joao

    2013-01-01

    The FK is a two-stage optical concentrator for CPV, composed by a Fresnel lens working as POE and a refractive element working as SOE. Both elements perform Köhler integration, for uniform irradiance purposes. The FK has demonstrated that compares very well with other Fresnel-based concentrator optics. Recent on-sun measurements carried out on an FK mono-module prototype have already shown outstanding results, achieving electrical efficiencies over 34%. Further optimization of optical design ...

  5. Concentrated poverty in Milwaukee

    OpenAIRE

    Jeremiah P. Boyle

    2009-01-01

    Hurricane Katrina and its aftermath created a renewed awareness of the unique isolation and vulnerability of people who live in communities where poverty concentrates and persists. The Federal Reserve’s Community Affairs staff partnered with the Brookings Institution to re-examine our understanding of concentrated poverty – defined as areas where at least 40 percent of the population lives below the poverty line.

  6. The Microwave Concentrator Design and Study on Concentrating Apple Juice

    OpenAIRE

    Geng Yuefeng; Ge Xinfeng

    2014-01-01

    Microwave concentrating device on fresh apple juice is designed in order to increase concentrating fresh apple juice efficiency and microwave concentrating process on fresh apple juice were studied. The designed microwave concentrator contains microwave generator, dehumidification system, electrical cabinet, parabolic waveguide, control system, microwave leakage inhibited mechanism and other components. The concentrating experiment is carried by the designed concentrator, from the setting-to-...

  7. Photovoltaic solar concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Nielson, Gregory N.; Gupta, Vipin P.; Okandan, Murat; Watts, Michael R.

    2016-03-15

    A photovoltaic solar concentrator is disclosed with one or more transverse-junction solar cells (also termed point contact solar cells) and a lens located above each solar cell to concentrate sunlight onto the solar cell to generate electricity. Piezoelectric actuators tilt or translate each lens to track the sun using a feedback-control circuit which senses the electricity generated by one or more of the solar cells. The piezoelectric actuators can be coupled through a displacement-multiplier linkage to provide an increased range of movement of each lens. Each lens in the solar concentrator can be supported on a frame (also termed a tilt plate) having three legs, with the movement of the legs being controlled by the piezoelectric actuators.

  8. Thermal cloak-concentrator

    Science.gov (United States)

    Shen, Xiangying; Li, Ying; Jiang, Chaoran; Ni, Yushan; Huang, Jiping

    2016-07-01

    For macroscopically manipulating heat flow at will, thermal metamaterials have opened a practical way, which possesses a single function, such as either cloaking or concentrating the flow of heat even though environmental temperature varies. By developing a theory of transformation heat transfer for multiple functions, here we introduce the concept of intelligent thermal metamaterials with a dual function, which is in contrast to the existing thermal metamaterials with single functions. By assembling homogeneous isotropic materials and shape-memory alloys, we experimentally fabricate a kind of intelligent thermal metamaterials, which can automatically change from a cloak (or concentrator) to a concentrator (or cloak) when the environmental temperature changes. This work paves an efficient way for a controllable gradient of heat, and also provides guidance both for arbitrarily manipulating the flow of heat and for efficiently designing similar intelligent metamaterials in other fields.

  9. Solar concentrator protective system

    Science.gov (United States)

    Selcuk, M. K. (Inventor)

    1984-01-01

    A mechanism that blocks concentrated sunlight from reaching a receiver, in the event of a tracking failure or loss of coolant is described. Sunlight is normally concentrated by a dish reflector onto the opening of a receiver. A faceplate surrounds the opening, and coolant carrying tubes, line the receiver. If the concentrated sunlight wanders so it begins to fall on the faceplate, then the sunlight will melt a portion of a fuse wire portion will break. The wire is attached to a flange on a shutter frame, and breaking of the fuse wire allows the frame to fall. Normally, the shutter frame supports shutter elements that are held open by cam followers that bear against cams.

  10. Pollutant concentrations in placenta

    DEFF Research Database (Denmark)

    Leino, O.; Kiviranta, H.; Karjalainen, A. K.;

    2013-01-01

    Unborn children are exposed to environmental pollutants via the placenta, and there is a causal relationship between maternal intake of pollutants and fetal exposure. Placental examination is an effective way for acquiring data for estimating fetal exposure. We analyzed the concentrations of 104...... congeners of persistent organic pollutants, seven organotin compounds, five heavy metals, and methylmercury in 130 randomly selected placentas. Additionally, we examined similarities between pollutant concentrations by analyzing correlations between their placental concentrations. Our results yield new...... information for conducting contaminant risk assessments for the prenatal period. Out of the 117 individual persistent organic pollutants or metals assayed, 46 could be detected in more than half of the placentas. Moreover, dichlorodiphenyldichloroethylene (p,p'-DDE) was found in all placentas. The data...

  11. Vacancy Concentration in Ice

    DEFF Research Database (Denmark)

    Mogensen, O. E.; Eldrup, Morten Mostgaard

    1977-01-01

    Based on the diffusion constant for self-diffusion in ice, which is believed to take place by a vacancy mechanism, we estimate the relative vacancy concentration near the melting point to be at least ∼ 10−6, i.e. much higher than previous estimates of about 10−10.......Based on the diffusion constant for self-diffusion in ice, which is believed to take place by a vacancy mechanism, we estimate the relative vacancy concentration near the melting point to be at least ∼ 10−6, i.e. much higher than previous estimates of about 10−10....

  12. Concentration among the rich

    OpenAIRE

    Atkinson, Anthony B.

    2006-01-01

    The aim of this paper is to examine the concentration of wealth among the group of top wealth holders, defined as those with wealth in excess of a high cut off. The paper begins by considering the definition of this cut off, analogous to the definition of a poverty line at the other end of the distribution. It then considers what can be learned about the proportion classified as ‘rich’ and about the concentration among the rich from four non-survey sources: journalists’ lists, estate data, we...

  13. Concentrated loads on concrete

    DEFF Research Database (Denmark)

    Lorenzen, Karen Grøndahl; Nielsen, Mogens Peter

    1997-01-01

    This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas are...

  14. Theory of Concentrated Vortices

    DEFF Research Database (Denmark)

    Alekseenko, Sergey; Kuibin, Pavel; Okulov, Valery

    This book presents comprehensive and authoritative coverage of the wide field of concentrated vortices observed in nature and technique. The methods for research of their kinematics and dynamics are considered. Special attention is paid to the flows with helical symmetry. The authors have described...

  15. Dilution, Concentration, and Flotation

    Science.gov (United States)

    Liang, Ling; Schmuckler, Joseph S.

    2004-01-01

    As both classroom teaching practice and literature show, many students have difficulties learning science concepts such as density. Here are some investigations that identify the relationship between density and floating through experimenting with successive dilution of a liquid, or the systematic change of concentration of a saltwater solution.…

  16. Scattering Solar Thermal Concentrators

    Energy Technology Data Exchange (ETDEWEB)

    Giebink, Noel C. [Pennsylvania State Univ., State College, PA (United States)

    2015-01-31

    This program set out to explore a scattering-based approach to concentrate sunlight with the aim of improving collector field reliability and of eliminating wind loading and gross mechanical movement through the use of a stationary collection optic. The approach is based on scattering sunlight from the focal point of a fixed collection optic into the confined modes of a sliding planar waveguide, where it is transported to stationary tubular heat transfer elements located at the edges. Optical design for the first stage of solar concentration, which entails focusing sunlight within a plane over a wide range of incidence angles (>120 degree full field of view) at fixed tilt, led to the development of a new, folded-path collection optic that dramatically out-performs the current state-of-the-art in scattering concentration. Rigorous optical simulation and experimental testing of this collection optic have validated its performance. In the course of this work, we also identified an opportunity for concentrating photovoltaics involving the use of high efficiency microcells made in collaboration with partners at the University of Illinois. This opportunity exploited the same collection optic design as used for the scattering solar thermal concentrator and was therefore pursued in parallel. This system was experimentally demonstrated to achieve >200x optical concentration with >70% optical efficiency over a full day by tracking with <1 cm of lateral movement at fixed latitude tilt. The entire scattering concentrator waveguide optical system has been simulated, tested, and assembled at small scale to verify ray tracing models. These models were subsequently used to predict the full system optical performance at larger, deployment scale ranging up to >1 meter aperture width. Simulations at an aperture widths less than approximately 0.5 m with geometric gains ~100x predict an overall optical efficiency in the range 60-70% for angles up to 50 degrees from normal. However, the

  17. Concentrated solar thermoelectric generators

    OpenAIRE

    Baranowski, Lauryn L.; Snyder, G. Jeffrey; Toberer, Eric S.

    2012-01-01

    Solar thermoelectric generators (STEGs) are solid state heat engines that generate electricity from concentrated sunlight. In this paper, we develop a novel detailed balance model for STEGs and apply this model to both state-of-the-art and idealized materials. This model uses thermoelectric compatibility theory to provide analytic solutions to device efficiency in idealized materials with temperature-dependent properties. The results of this modeling allow us to predict maximum theoretical ST...

  18. Chlorination of zirconyte concentrate

    International Nuclear Information System (INIS)

    Chlorination experiments with zirconyte concentrate were carried out in order to study the effects of temperature, percentage of reducing agent and porosity on the gasification of ZrO2 for 10 and 20 minutes of reaction. Factorial analysis was applied and the results indicated that temperature and percentage of reducing agent were the two only variables effecting the ZrO2 gasification. (author)

  19. Electrolyte Concentrates Treat Dehydration

    Science.gov (United States)

    2009-01-01

    Wellness Brands Inc. of Boulder, Colorado, exclusively licensed a unique electrolyte concentrate formula developed by Ames Research Center to treat and prevent dehydration in astronauts returning to Earth. Marketed as The Right Stuff, the company's NASA-derived formula is an ideal measure for athletes looking to combat dehydration and boost performance. Wellness Brands also plans to expand with products that make use of the formula's effective hydration properties to help treat conditions including heat stroke, altitude sickness, jet lag, and disease.

  20. Zirconia concentrate chlorination

    International Nuclear Information System (INIS)

    Chlorination experiments were conducted in order to study the kinetics of gasification of the zirconium oxide present in the zirconia concentrate. The variables studied are temperature (1173 to 1373 K), percentage of reducing agent (12 to 36%) and porosity (22 to 30%). The results indicated a greater influence of temperature and percentage of reducing agent as well as allowed the conclusion that a balance between the levels of these variables is an important factor in the appropriate chlorination conditions. (author)

  1. Carbon Concentration of Austenite

    Directory of Open Access Journals (Sweden)

    Z. Ławrynowicz

    2007-07-01

    Full Text Available The investigation was carried out to examine the influence of temperature and times of austempering process on the maximum extend towhich the bainite reaction can proceed and the carbon content in retained austenite. It should be noted that a small percentage change in theaustenite carbon content can have a significant effect on the subsequent austempering reaction changing the volume fraction of the phasespresent and hence, the resulting mechanical properties. Specimens were prepared from an unalloyed ductile cast iron, austenitised at 950oCfor 60 minutes and austempered by the conventional single-step austempering process at four temperatures between BS and MS, eg., 250,300, 350 and 400oC. The samples were austempered at these temperatures for 15, 30, 60, 120 and 240 minutes and finally quenched toambient temperature. Volume fractions of retained austenite and carbon concentration in the residual austenite have been observed byusing X-ray diffraction. Additionally, carbon concentration in the residual austenite was calculated using volume fraction data of austeniteand a model developed by Bhadeshia based on the McLellan and Dunn quasi-chemical thermodynamic model. The comparison ofexperimental data with the T0, T0' and Ae3' phase boundaries suggests the likely mechanism of bainite reaction in cast iron is displacive rather than diffusional. The carbon concentration in retained austenite demonstrates that at the end of bainite reaction the microstructure must consist of not only ausferrite but additionally precipitated carbides.

  2. Concentrated Solar Thermoelectric Power

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Gang [MIT; Ren, Zhifeng [University of Houston

    2015-07-09

    The goal of this project is to demonstrate in the lab that solar thermoelectric generators (STEGs) can exceed 10% solar-to-electricity efficiency, and STEGs can be integrated with phase-change materials (PCM) for thermal storage, providing operation beyond daylight hours. This project achieved significant progress in many tasks necessary to achieving the overall project goals. An accurate Themoelectric Generator (TEG) model was developed, which included realistic treatment of contact materials, contact resistances and radiative losses. In terms of fabricating physical TEGs, high performance contact materials for skutterudite TE segments were developed, along with brazing and soldering methods to assemble segmented TEGs. Accurate measurement systems for determining device performance (in addition to just TE material performance) were built for this project and used to characterize our TEGs. From the optical components’ side, a spectrally selective cermet surface was developed with high solar absorptance and low thermal emittance, with thermal stability at high temperature. A measurement technique was also developed to determine absorptance and total hemispherical emittance at high temperature, and was used to characterize the fabricated spectrally selective surfaces. In addition, a novel reflective cavity was designed to reduce radiative absorber losses and achieve high receiver efficiency at low concentration ratios. A prototype cavity demonstrated that large reductions in radiative losses were possible through this technique. For the overall concentrating STEG system, a number of devices were fabricated and tested in a custom built test platform to characterize their efficiency performance. Additionally, testing was performed with integration of PCM thermal storage, and the storage time of the lab scale system was evaluated. Our latest testing results showed a STEG efficiency of 9.6%, indicating promising potential for high performance concentrated STEGs.

  3. Concentration and content

    OpenAIRE

    Fuentes-Arderiu, Xavier

    2013-01-01

    One of the more frequent activities in health sciences is the measurement of biological quantities. Frequently, when reading biomedical books and journals some confusion on the metrological mea-ning of biological quantities related to the concepts ‘concentration’ and ‘content’ may be observed. Classically, a concentration is an amount of any type per volume of liquid or gas system, whereas content is an amount of any type per mass of liquid or gas or solid system. However the concepts ‘concen...

  4. Concentration and content

    OpenAIRE

    Fuentes-Arderiu, Xavier

    2013-01-01

    One of the more frequent activities in health sciences is the measurement of biological quantities. Frequently, when reading biomedical books and journals some confusion on the metrological meaning of biological quantities related to the concepts ‘concentration’ and ‘content’ may be observed. Classically, a concentration is an amount of any type per volume of liquid or gas system, whereas content is an amount of any type per mass of liquid or gas or solid system. However the concepts ‘concent...

  5. Boric acid concentration monitoring

    International Nuclear Information System (INIS)

    Boric acid concentration was measured by thermal neutron absorption in the study of the boric acid sorption and desorption curves on an anion exchange resin. Ra-Be 18.5 GBq and Am-Be 111 GBq sources and water as a moderator were used. The SNM 12 cylindrical corona detector with 10B placed in the middle of the measuring cell was used for neutron flux measurement. The HP 9600 E computer system was used for measured data collection and evaluation. (Ha)

  6. Membrane distillation for milk concentration

    NARCIS (Netherlands)

    Moejes, S.N.; Romero Guzman, Maria; Hanemaaijer, J.H.; Barrera, K.H.; Feenstra, L.; Boxtel, van A.J.B.

    2015-01-01

    Membrane distillation is an emerging technology to concentrate liquid products while producing high quality water as permeate. Application for desalination has been studied extensively the past years, but membrane distillation has also potential to produce concentrated food products like concentrate

  7. Plasma concentrations of misonidazole

    International Nuclear Information System (INIS)

    The plasma concentrations of misonidazole doses between 0.6 and 2.0 g/m2 were analyzed in respect to the variation within the same patient and between different patients. Peak plasma levels were observed after 2 hours. The mean plasma levels of misonidazole only at 3 hours were 23.8, 47.0 and 76.5 μg/ml after misonidazole doses of 0.6, 1.2 g/m2, respectively. The half-life of misonidazole only was found to be 8.2 hours for women and 10.5 for men. Good linearity between plasma levels and drug doses was observed after administration of different single doses to the same patient within the dose range 0.6 to 2.0 g/m2. (orig.)

  8. Concentration solar thermal power

    International Nuclear Information System (INIS)

    As the production of electricity by concentration solar power (CSP) installations is said to be a source of energy for the future, the author discusses past experiments (notably the French Thermis project), and the different techniques which are currently being used. He indicates the regions which appear to be the most appropriate for this technique. He presents the three main techniques: parabolic cylinder, tower, and Stirling cycle installations. He discusses the issue of intermittency. He proposes an assessment of prices and of their evolution, and indicates the investments made in different installations (in Italy, Spain, Germany and Portugal). He comments the case of hybrid installations (sun and gas), evokes the Desertec project proposed by the German industry which comprises a set of hybrid installations. He notices that there is no significant technological evolution for this process

  9. Concentrating solar thermal power.

    Science.gov (United States)

    Müller-Steinhagen, Hans

    2013-08-13

    In addition to wind and photovoltaic power, concentrating solar thermal power (CSP) will make a major contribution to electricity provision from renewable energies. Drawing on almost 30 years of operational experience in the multi-megawatt range, CSP is now a proven technology with a reliable cost and performance record. In conjunction with thermal energy storage, electricity can be provided according to demand. To date, solar thermal power plants with a total capacity of 1.3 GW are in operation worldwide, with an additional 2.3 GW under construction and 31.7 GW in advanced planning stage. Depending on the concentration factors, temperatures up to 1000°C can be reached to produce saturated or superheated steam for steam turbine cycles or compressed hot gas for gas turbine cycles. The heat rejected from these thermodynamic cycles can be used for sea water desalination, process heat and centralized provision of chilled water. While electricity generation from CSP plants is still more expensive than from wind turbines or photovoltaic panels, its independence from fluctuations and daily variation of wind speed and solar radiation provides it with a higher value. To become competitive with mid-load electricity from conventional power plants within the next 10-15 years, mass production of components, increased plant size and planning/operating experience will be accompanied by technological innovations. On 30 October 2009, a number of major industrial companies joined forces to establish the so-called DESERTEC Industry Initiative, which aims at providing by 2050 15 per cent of European electricity from renewable energy sources in North Africa, while at the same time securing energy, water, income and employment for this region. Solar thermal power plants are in the heart of this concept. PMID:23816910

  10. Workplace concentration of immigrants.

    Science.gov (United States)

    Andersson, Fredrik; García-Pérez, Mónica; Haltiwanger, John; McCue, Kristin; Sanders, Seth

    2014-12-01

    Casual observation suggests that in most U.S. urban labor markets, immigrants have more immigrant coworkers than native-born workers do. While seeming obvious, this excess tendency to work together has not been precisely measured, nor have its sources been quantified. Using matched employer-employee data from the U.S. Census Bureau Longitudinal Employer-Household Dynamics (LEHD) database on a set of metropolitan statistical areas (MSAs) with substantial immigrant populations, we find that, on average, 37 % of an immigrant's coworkers are themselves immigrants; in contrast, only 14 % of a native-born worker's coworkers are immigrants. We decompose this difference into the probability of working with compatriots versus with immigrants from other source countries. Using human capital, employer, and location characteristics, we narrow the mechanisms that might explain immigrant concentration. We find that industry, language, and residential segregation collectively explain almost all the excess tendency to work with immigrants from other source countries, but they have limited power to explain work with compatriots. This large unexplained compatriot component suggests an important role for unmeasured country-specific factors, such as social networks. PMID:25425452

  11. Geographic Concentration in China's Manufacturing

    Institute of Scientific and Technical Information of China (English)

    Zhang Tongsheng; Gan Guohui

    2006-01-01

    This paper empirically examines variations and changes in manufacturing concentration and their determinants in China over the 1980-2003period with a sample of 26 industries. The analysis indicates that average industrial concentration has increased during the 1990s. Studies show that scale economies and industry policies are important determinants for industries geographical concentration; factor endowments and the location of foreign direct investment are also found to have a positive effect on concentration.

  12. Bronchial secretion concentrations of tobramycin.

    Science.gov (United States)

    Alexander, M R; Schoell, J; Hicklin, G; Kasik, J E; Coleman, D

    1982-02-01

    The mean concentrations of tobramycin in bronchial secretions from patients with pneumonia were almost two times greater than secretions from patients free of lung infection. Mean tobramycin bronchial secretion to serum concentration ratios also were higher when obtained from infected lungs (0.66 versus 0.17) These data suggest that lung infection enhances the concentrations of tobramycin in bronchial secretions. PMID:7065524

  13. MARKET CONCENTRATION AND ECONOMIC PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Sophia Nikolaevna Lyubyaschenko

    2013-10-01

    Full Text Available In this paper, we describe the trend of market concentration, the formation of strategic groups in Russian industry, principles of integration of firms in strategic groups, and the reasons for increase of market concentration. Purpose - to propose the methods of measuring industry concentration in terms of coordination.   Methodology: methods of system analysis, economic analysis, the methodological approaches of the theory of industrial organization, regression analysis.Results: Authors provide the methods of measuring industry concentration in terms of coordination. Authors established laws of formation of strategic groups (coalitions. The relationship between the concentration rate and business cycle sensitivity of firms in Russian industry was described.Practical implications: The methods of measuring industry concentration is of interest to economists, business strategists, and government agencies.DOI: http://dx.doi.org/10.12731/2218-7405-2013-7-36

  14. School concentration and school travel

    NARCIS (Netherlands)

    De Boer, E.

    2010-01-01

    The purpose of the research as described in this Doctor’s thesis is twofold. Firstly it is to define in how far Dutch facilities for primary and secondary education were subjected to spatial concentration during recent decades. Secondly it is intended to assess what this concentration implied for th

  15. Radon concentration in The Netherlands

    International Nuclear Information System (INIS)

    In 1000 dwellings, which can be assumed to be an reasonable representation of the average Dutch dwellings, time averaged radon concentrations, radon daughter concentrations and gamma-exposure tempi are determined during a year with passive dosemeters. They are also determined outdoor at circa 200 measure points. (Auth.)

  16. Inflatable Solar Thermal Concentrator Delivered

    Science.gov (United States)

    Tolbert, Carol M.

    1999-01-01

    Space-based solar thermal power systems are very appealing as a space power source because they generate power efficiently. However, solar thermal (dynamic) systems currently incorporate rigid concentrators that are relatively heavy and require significant packaging volume and robust deployment schemes. In many ways, these requirements make these systems less appealing than photovoltaic systems. As an alternative to solar thermal power systems with rigid concentrators, solar thermal power systems with thin film inflation-deployed concentrators have low cost, are lightweight, and are efficiently packaged and deployed. Not only are inflatable concentrators suitable for low Earth orbit and geosynchronous orbit applications, but they can be utilized in deep space missions to concentrate solar energy to high-efficiency solar cells.

  17. Flame Propagation Through Concentration Gradient

    Institute of Scientific and Technical Information of China (English)

    JunyaIINO; MitsuakiTANABE; 等

    2000-01-01

    The experiment was carried out in homogeneous propane-air mixture and in several concentration gradient of mixture.Igniter is put on the upper side of the combustion chamber,In concentration gradient experiment.ixture was ignited from lean side.An experimental study was conducted in a combustion chamber.The combustion chamber has glass windows for optical measurements at any side.For the measurement of distribution of fuel concentration,infraed absorption method using 3.39μm He-Ne laser was used,and for the observation of proagating flams,Schlieren method was employed.As a measurment result of flame propagation velocity and flammable limit,for a mixture of an identical local equivalence ratio.flame propagation velocity in concentration gradient is faster than that in homogeneous mixture,and rich flammable limit in concentration gradient shows a tendency to be higher than that in homogeneous mixture.

  18. The Electrostatic Screening Length in Concentrated Electrolytes Increases with Concentration

    OpenAIRE

    Smith, Alexander M.; Lee, Alpha A.; Perkin, Susan

    2016-01-01

    According to classical electrolyte theories interactions in dilute (low ion density) electrolytes decay exponentially with distance, with the Debye screening length the characteristic length-scale. This decay length decreases monotonically with increasing ion concentration, due to effective screening of charges over short distances. Thus within the Debye model no long-range forces are expected in concentrated electrolytes. Here we reveal, using experimental detection of the interaction betwee...

  19. Tank waste concentration mechanism study

    International Nuclear Information System (INIS)

    This study determines whether the existing 242-A Evaporator should continue to be used to concentrate the Hanford Site radioactive liquid tank wastes or be replaced by an alternative waste concentration process. Using the same philosophy, the study also determines what the waste concentration mechanism should be for the future TWRS program. Excess water from liquid DST waste should be removed to reduce the volume of waste feed for pretreatment, immobilization, and to free up storage capacity in existing tanks to support interim stabilization of SSTS, terminal cleanout of excess facilities, and other site remediation activities

  20. Biodegradation kinetics at low concentrations (

    DEFF Research Database (Denmark)

    Toräng, Lars; Albrechtsen, Hans-Jørgen; Nyholm, Niels

    2000-01-01

    Aerobic biodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D) was studied in groundwater added sediment fines. At concentrations at or below 1 mu g/L of 2,4-D degradation kinetic was of true first order without significant growth of specific degraders and with half-life for mineralization in the...... order of 200 days. Higher concentrations of 2,4-D resulted in a grossly overestimate of the actual degradation rate for concentrations characteristic for Danish found in groundwater....

  1. Qualification testing of photovoltaic concentrators

    Science.gov (United States)

    Richards, E. H.; Barlow, R. S.

    Sandia has developed a revised set of specifications for qualification testing of passively-cooled photovoltaic concentrator modules. The purpose of the tests is to screen new concentrator designs and new production runs for susceptibility to known failure mechanisms; concentrator hardware must be qualified prior to array-level installation at Sandia's Photovoltaic Advanced System Test Facility (PASTF). Tests for cell assemblies and receiver sections, as well as for complete modules, are specified. They include ultraviolet radiation testing of materials, characterization of electrical performance checks to assure safety and structural integrity of modules, and accelerated environmental aging or cycling.

  2. Qualification testing of photovoltaic concentrators

    International Nuclear Information System (INIS)

    Sandia has developed a revised set of specifications for qualification testing of passively-cooled photovoltaic concentrator modules. The purpose of the tests is to screen new concentrator designs and new production runs for susceptibility to known failure mechanisms; concentrator hardware must be qualified prior to array-level installation at Sandia's Photovoltaic Advanced System Test Facility (PASTF). Tests for cell assemblies and receiver sections, as well as for complete modules, are specified. They include ultraviolet radiation testing of materials, characterization of electrical performance, checks to assure safety and structural integrity of modules, and accelerated environmental aging or cycling

  3. Process for purifying molybdenite concentrates

    Energy Technology Data Exchange (ETDEWEB)

    Austin, J.W.; Bradburn, R.G.; Cromwell, C.A.; Gratch, E.; Groiss, E.; Perkins, D.; Walker, R.A.

    1985-02-19

    An improved process is disclosed for the treatment of molybdenite concentrate to remove impurities, such as copper and lead therefrom. According to this process, ferrous chloride liquor is introduced into a reactor which is made of a material that can withstand leaching with the use of ferric chloride at elevated temperatures and pressures. Sodium or calcium chloride may also be added to the reactor which is then sealed and subjected to chlorination until the rise in temperature, due to the exothermicity of the reaction, produces the desired concentration of the ferric ion to leach the impurities present in the concentrate to a desired level. Upon completion of the chlorination, the molybdenite concentrate is introduced into the reactor and is leached therein. Finally, the resulting pulp is filtered and washed to obtain the desired purified product.

  4. Fibrinogen concentrate in bleeding patients

    DEFF Research Database (Denmark)

    Wikkelsø, Anne; Lunde, Jens; Johansen, Mathias;

    2013-01-01

    Hypofibrinogenaemia is associated with increased morbidity and mortality, but the optimal treatment level, the use of preemptive treatment and the preferred source of fibrinogen remain disputed. Fibrinogen concentrate is increasingly used and recommended for bleeding with acquired haemostatic...

  5. School concentration and school travel

    OpenAIRE

    Boer, E. de

    2010-01-01

    The purpose of the research as described in this Doctor’s thesis is twofold. Firstly it is to define in how far Dutch facilities for primary and secondary education were subjected to spatial concentration during recent decades. Secondly it is intended to assess what this concentration implied for the development of the minimum necessary travel distances to school, with its consequences for school choice and for school travel mode use. The phenomenon of ‘school concentration’ is explored and d...

  6. Teorell instability in concentration polarization.

    Science.gov (United States)

    Abu-Rjal, Ramadan; Prigozhin, Leonid; Rubinstein, Isaak; Zaltzman, Boris

    2015-08-01

    We investigate the development of electro-osmotic (Teorell) oscillations at a weakly charged microporous membrane without a preimposed transmembrane electrolyte concentration drop. This drop, necessary for the occurrence of oscillations, develops spontaneously as a result of concentration polarization in the solution layers adjacent to the membrane. A three-layer model comprising a membrane flanked by two diffusion layers is proposed and analyzed for galvano- and potentiostatic regimes of operation. PMID:26382404

  7. How Concentration Shields Against Distraction

    OpenAIRE

    Sörqvist, Patrik; Marsh, John E.

    2015-01-01

    In this article, we outline our view of how concentration shields against distraction. We argue that higher levels of concentration make people less susceptible to distraction for two reasons. One reason is that the undesired processing of the background environment is reduced. For example, when people play a difficult video game, as opposed to an easy game, they are less likely to notice what people in the background are saying. The other reason is that the locus of attention becomes more st...

  8. The Electrostatic Screening Length in Concentrated Electrolytes Increases with Concentration.

    Science.gov (United States)

    Smith, Alexander M; Lee, Alpha A; Perkin, Susan

    2016-06-16

    According to classical electrolyte theories interactions in dilute (low ion density) electrolytes decay exponentially with distance, with the Debye screening length the characteristic length scale. This decay length decreases monotonically with increasing ion concentration due to effective screening of charges over short distances. Thus, within the Debye model no long-range forces are expected in concentrated electrolytes. Here we reveal, using experimental detection of the interaction between two planar charged surfaces across a wide range of electrolytes, that beyond the dilute (Debye-Hückel) regime the screening length increases with increasing concentration. The screening lengths for all electrolytes studied-including aqueous NaCl solutions, ionic liquids diluted with propylene carbonate, and pure ionic liquids-collapse onto a single curve when scaled by the dielectric constant. This nonmonotonic variation of the screening length with concentration, and its generality across ionic liquids and aqueous salt solutions, demonstrates an important characteristic of concentrated electrolytes of substantial relevance from biology to energy storage. PMID:27216986

  9. High concentration linear Fresnel reflectors

    International Nuclear Information System (INIS)

    Highlights: • Linear Fresnel reflectors (LFRs) have great potential for cost reductions. • Concentration in the receiver central strip as high as in trough collectors. • Daily constant flux map in the receiver if the filling factor is adequately designed. • High concentration variation between summer and winter for N–S configurations. - Abstract: The late exponential development of Concentrating Solar Power (CSP) technology has driven to a very high power installed worldwide, but with no time for global optimization of the technology. High feed-in-tariffs have concentrated investments on trough collectors and central towers, previously studied during the 1980s. Linear Fresnel reflectors (LFRs) are regarded as a low efficiency technology, which is mainly due to very little previous research. However, the use of slightly bent mirrors drives to high concentration ratios, with obvious cost advantages over other CSP technologies. This paper studies the radiation flux obtained in a flat receiver using different mirror shapes, and analyzes its variation along the year. Linear Fresnel reflector design variables are reviewed, and a Ray Tracing model of the Fresdemo prototype is carried out. Results show higher performances than expected

  10. Concentration Bounds for Stochastic Approximations

    CERN Document Server

    Frikha, Noufel

    2012-01-01

    We obtain non asymptotic concentration bounds for two kinds of stochastic approximations. We first consider the deviations between the expectation of a given function of the Euler scheme of some diffusion process at a fixed deterministic time and its empirical mean obtained by the Monte-Carlo procedure. We then give some estimates concerning the deviation between the value at a given time-step of a stochastic approximation algorithm and its target. Under suitable assumptions both concentration bounds turn out to be Gaussian. The key tool consists in exploiting accurately the concentration properties of the increments of the schemes. For the first case, as opposed to the previous work of Lemaire and Menozzi (EJP, 2010), we do not have any systematic bias in our estimates. Also, no specific non-degeneracy conditions are assumed.

  11. Radioiodine concentrated in a wetland

    International Nuclear Information System (INIS)

    Most subsurface environmental radioactivity contamination is expected to eventually resurface in riparian zones, or wetlands. There are a number of extremely sharp biogeochemical interfaces in wetlands that could alter radionuclide speciation and promote accumulation. The objective of this study was to determine if a wetland concentrated 129I emanating from a former waste disposal basin located on the Savannah River Site (SRS) in South Carolina, USA. Additionally, studies were conducted to evaluate the role of sediment organic matter in immobilizing the radioiodine. Groundwater samples were collected along a 0.7-km transect away from the seepage basin and in the downstream wetlands. The samples were analyzed for 129I speciation (iodide (I−), iodate (IO3−), and organo-I). Groundwater 129I concentrations in many locations in the wetlands (as high as 59.9 Bq L−1129I) were greatly elevated with respect to the source term (5.9 Bq L−1129I). 129I concentration profiles in sediment cores were closely correlated to organic matter concentrations (r2 = 0.992; n = 5). While the sediment organic matter promoted the uptake of 129I to the wetland sediment, it also promoted the formation of a soluble organic fraction: 74% of the wetland groundwater 129I could pass through a 1 kDa (<1 nm) membrane and only 26% of the 129I was colloidal. Of that fraction that could pass through a 1 kDa membrane, 39% of the 129I was organo-I. Therefore, while wetlands may be highly effective at immobilizing aqueous 129I, they may also promote the formation of a low-molecular-weight organic species that does not partition to sediments. This study provides a rare example of radioactivity concentrations increasing rather than decreasing as it migrates from a point source and brings into question assumptions in risk models regarding continuous dilution of released contaminants. - Highlights: • 129I emanating from a former waste disposal basin is concentrating in a wetland located ∼700 m

  12. Positron flux concentrator - an update

    International Nuclear Information System (INIS)

    The type of concentrator that has been under study (on and off) for the last two years is shown. The work was started by Dave Sherden and Co., and the object of the study was (and still is) to determine the correct parameters which will give the correct field in the central region which captures the maximum number of e+'s from the target. This note contains two sections. The first is a simplified model which seems to agree with most of the measurements carried out. The second describes the set up, a typical example of the field's shape and amplitude and the electrical requirements for the final concentrator

  13. Eigenfunction concentration for polygonal billiards

    OpenAIRE

    Hassell, Andrew; Hillairet, Luc; Marzuola, Jeremy

    2008-01-01

    In this note, we extend the results on eigenfunction concentration in billiards as proved by the third author in \\cite{M1}. There, the methods developed in Burq-Zworski \\cite{BZ3} to study eigenfunctions for billiards which have rectangular components were applied. Here we take an arbitrary polygonal billiard $B$ and show that eigenfunction mass cannot concentrate away from the vertices; in other words, given any neighbourhood $U$ of the vertices, there is a lower bound $$ \\int_U |u|^2 \\geq c...

  14. Study on magnetic concentration of Nigerian Itakpe sinter concentrate to a Midrex-grade concentrate

    Directory of Open Access Journals (Sweden)

    Adewale O. Adeleke

    2009-10-01

    Full Text Available The sinter grade of the Nigerian Itakpe iron ore that assayed 63.63% Fe and 6.62% total acid gangue was subjected to both wet low-intensity magnetic separation (LIMS and wet high-intensity magnetic separation (WHIMS to upgrade it to Midrex-grade super-concentrate. Chemical analysis conducted on the super-concentrate samples from LIMS and WHIMS gave Fe content of 67.59% and 68.70%, and lower acid gangue of 1.55% and 3.22% respectively. However, screen distribution analysis results showed that the cumulative fractions passing 45-m sieve were 0.88% and 0.38% for LIMS and WHIMS super-concentrates respectively. These results indicate that the Fe and acid content determined for both LIMS and WHIMS meets the requirement for a Midrex-grade super-concentrate, while the fractions of the concentrate passing 45-m sieve are below the 30% upper limit for transportation to the reduction plant.

  15. City scale pollen concentration variability

    Science.gov (United States)

    van der Molen, Michiel; van Vliet, Arnold; Krol, Maarten

    2016-04-01

    Pollen are emitted in the atmosphere both in the country-side and in cities. Yet the majority of the population is exposed to pollen in cities. Allergic reactions may be induced by short-term exposure to pollen. This raises the question how variable pollen concentration in cities are in temporally and spatially, and how much of the pollen in cities are actually produced in the urban region itself. We built a high resolution (1 × 1 km) pollen dispersion model based on WRF-Chem to study a city's pollen budget and the spatial and temporal variability in concentration. It shows that the concentrations are highly variable, as a result of source distribution, wind direction and boundary layer mixing, as well as the release rate as a function of temperature, turbulence intensity and humidity. Hay Fever Forecasts based on such high resolution emission and physical dispersion modelling surpass traditional hay fever warning methods based on temperature sum methods. The model gives new insights in concentration variability, personal and community level exposure and prevention. The model will be developped into a new forecast tool to serve allergic people to minimize their exposure and reduce nuisance, coast of medication and sick leave. This is an innovative approach in hay fever warning systems.

  16. Biodegradation kinetics at low concentrations (

    DEFF Research Database (Denmark)

    Toräng, Lars; Albrechtsen, Hans-Jørgen; Nyholm, Niels

    Aerobic biodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D) was studied in groundwater added sediment fines. At concentrations at or below 1 mu g/L of 2,4-D degradation kinetic was of true first order without significant growth of specific degraders and with half-life for mineralization in the...

  17. Indoor radon concentration in Poland

    International Nuclear Information System (INIS)

    Preliminary survey of Rn concentration indoors by means of track detectors and y-ray dose rate with the use of TLD in almost 500 homes in selected areas of Poland was performed in the late 1980s. It was concluded that radon contributes 1.16 mSv i.e. about 46 per cent of the total natural environment ionizing radiation dose to the Polish population. Comparison of the average radon concentrations in 4 seasons of a year and in 3 groups of buildings: masonry, concrete and wood, revealed that the ground beneath the building structure is likely the dominant source of radon indoors. Since the National Atomic Energy Agency in its regulations of 1988-03-31 set up the permissible limit of the equilibrium equivalent concentration of radon in new buildings (equal 100 Bq/m3), the nation-scale survey project for radon in buildings has been undertaken. These regulations were supposed to take effect in 1995-01-01. The project has 3 objectives: to estimate the radiation exposure due to radon daughters received by Polish population to identify radon-prone areas in Poland to investigate dependence of the indoor radon concentrations on such parameters as: type of construction material, presence (or absence) of cellar under the building, number of floor

  18. Cesium Concentration in MCU Solvent

    International Nuclear Information System (INIS)

    During Modular Caustic-Side Solvent Extraction (CSSX) Unit (MCU) operations, Cs-137 concentrations in product streams will vary depending on the location in the process and on the recent process conditions. Calculations of cesium concentrations under a variety of operating conditions reveal the following: (1) Under nominal operations with salt solution feed containing 1.1 Ci Cs-137 per gallon, the maximum Cs-137 concentration in the process will occur in the strip effluent (SE) and equal 15-16.5 Ci/gal. (2) Under these conditions, the majority of the solvent will contain 0.005 to 0.01 Ci/gal, with a limited portion of the solvent in the contactor stages containing ∼4 Ci/gal. (3) When operating conditions yield product near 0.1 Ci Cs-137/gal in the decontaminated salt solution (DSS), the SE cesium concentration will be the same or lower than in nominal operations, but majority of the stripped solvent will increase to ∼2-3 Ci/gal. (4) Deviations in strip and waste stream flow rates cause the largest variations in cesium content: (a) If strip flow rates deviate by -30% of nominal, the SE will contain ∼23 Ci/gal, although the cesium content of the solvent will increase to only 0.03 Ci/gal; (b) If strip flow rate deviates by -77% (i.e., 23% of nominal), the SE will contain 54 Ci/gal and solvent will contain 1.65 Ci/gal. At this point, the product DSS will just reach the limit of 0.1 Ci/gal, causing the DSS gamma monitors to alarm; and (c) Moderate (+10 to +30%) deviations in waste flow rate cause approximately proportional increases in the SE and solvent cesium concentrations. Recovery from a process failure due to poor cesium stripping can achieve any low cesium concentration required. Passing the solvent back through the contactors while recycling DSS product will produce a ∼70% reduction during one pass through the contactors (assuming the stripping D value is no worse than 0.36). If the solvent is returned to the solvent hold tank (containing additional

  19. Study on magnetic concentration of Nigerian Itakpe sinter concentrate to a Midrex-grade concentrate

    OpenAIRE

    Adewale O. Adeleke

    2009-01-01

    The sinter grade of the Nigerian Itakpe iron ore that assayed 63.63% Fe and 6.62% total acid gangue was subjected to both wet low-intensity magnetic separation (LIMS) and wet high-intensity magnetic separation (WHIMS) to upgrade it to Midrex-grade super-concentrate. Chemical analysis conducted on the super-concentrate samples from LIMS and WHIMS gave Fe content of 67.59% and 68.70%, and lower acid gangue of 1.55% and 3.22% respectively. However, screen distribution analysis results showed tha...

  20. Uranium Ore and Concentrate Sampling

    International Nuclear Information System (INIS)

    The Grand Junction Office of the United States Atomic Energy Commission has been responsible for procuring large quantities of natural uranium in both ores and concentrates. The techniques used for sampling ores are necessarily different from those used for concentrates. Each step in the overall measurement and sampling systems for both ores and concentrates is discussed, giving particular attention to the accuracy and precision of that step. During the years 1948-1964, a total of 58 million tons of ore was sampled in about 40 different mechanical sampling plants in the western United States. All plants have been required to weigh, sample and analyse ore in accordance with practices satisfactory to the USAEC. The ordinary principles of ore sampling, as used for years in the mining industry, have been followed. However, sufficient check sampling and other tests were performed to ensure that the uranium content of the variety of ores sampled was as accurately determined as economically feasible. Concentrates containing about 129 000 t of U3O8 were purchased from domestic producers during the last 17 years. This uranium was contained in approximately 10 000 lots, each of which was weighed, sampled, and analysed in accordance with carefully controlled procedures. These lots were received at USAEC-owned sampling facilities at Grand Junction or Weldon Spring, Missouri, both of which are contractor operated. The average lot consists of about 50 drums (55-gallon size) and weighs approximately 35 000 lb. Because concentrate varies so much in both physical and chemical characteristics, it is necessary to sample each drum. Through the years, various sampling systems were used, such as pipes, open auger, enclosed augers, and falling stream sampling. Falling stream sampling is the most accurate, provided precautions are taken to prevent changes in weight due to exposure to the atmosphere. Because of the tendency of concentrates to sorb or desorb moisture, depending upon the

  1. Concentrated solar power: an overview

    International Nuclear Information System (INIS)

    Solar thermal power is a relatively new technology and a fine arrangement for the provision of Electrical Energy and Clean Energy in general .The concentrated solar offers a viable option for the Sunny Zones of the world. The efficiency of the System depends on a few factors like Area, Intensity of Sunlight, Type of receiver, Hybridisation etc. Solar Thermal Systems employ lenses or mirrors to focus a large area of sunlight onto a small area. Electrical power is produced when the concentrated light is impugned onto photovoltaic cell made surfaces or used to heat a transfer fluid for a conventional power plant. In this paper we give a brief overview of a baseline Solar Thermal Power Plant, Technological details, Cost and Benefit analysis, a glimpse of solar thermal power and future of solar thermal power. (author)

  2. Pelletizing of sulfide molybdenite concentrates

    Science.gov (United States)

    Palant, A. A.

    2007-04-01

    The results of a pelletizing investigation using various binding components (water, syrup, sulfite-alcohol distillery grains, and bentonite) of the flotation sulfide molybdenite concentrate (˜84% MoS2) from the Mongolian deposit are discussed. The use of syrup provides rather high-strength pellets (>3 N/pellet or >300 g/pellet) of the required size (2 3 mm) for the consumption of 1 kg binder per 100 kg concentrate. The main advantage of the use of syrup instead of bentonite is that the molybdenum cinder produced by oxidizing roasting of raw ore materials is not impoverished due to complete burning out of the syrup. This fact exerts a positive effect on the subsequent hydrometallurgical process, decreasing molybdenum losses related to dump cakes.

  3. Vertical distribution of sediment concentration

    Institute of Scientific and Technical Information of China (English)

    Sai-hua HUANG; Zhi-lin SUN; Dan XU; Shan-shan XIA

    2008-01-01

    A simple formula is proposed to predict the vertical distribution of a suspended load concentration in a 2D steady turbulent flow.The proposed formula significantly improves the well-known Rouse formula where sediment concentration has an infinitely large value at the channel bottom and a zero value at the water surface.Based on this formula and the logarithmic ve-locity profile,a theoretical elementary function for the transport rate of a suspended load is developed.This equation improves the Einstein equation in which the unit-width suspended sediment discharge must be solved by numerical integration and a contra-diction between the lower limit of the integral and that of velocity distribution exists.

  4. Concentrating Solar Power Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    None

    2015-12-01

    This fact sheet is an overview of the Concentrating Solar Power (CSP) subprogram at the U.S. Department of Energy SunShot Initiative. CSP is a dispatchable, renewable energy option that uses mirrors to focus and concentrate sunlight onto a receiver, from which a heat transfer fluid carries the intense thermal energy to a power block to generate electricity. CSP systems can store solar energy to be used when the sun is not shining. It will help meet the nation’s goal of making solar energy fully cost-competitive with other energy sources by the end of the decade. Worldwide, CSP activity is rapidly scaling, with approximately 10 gigawatts (GW) in various stages of operation or development. In the United States alone, nearly 2 GW of CSP are in operation.

  5. Cylindrical acoustic levitator/concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Kaduchak, Gregory (Los Alamos, NM); Sinha, Dipen N. (Los Alamos, NM)

    2002-01-01

    A low-power, inexpensive acoustic apparatus for levitation and/or concentration of aerosols and small liquid/solid samples having particulates up to several millimeters in diameter in air or other fluids is described. It is constructed from a commercially available, hollow cylindrical piezoelectric crystal which has been modified to tune the resonance frequency of the breathing mode resonance of the crystal to that of the interior cavity of the cylinder. When the resonance frequency of the interior cylindrical cavity is matched to the breathing mode resonance of the cylindrical piezoelectric transducer, the acoustic efficiency for establishing a standing wave pattern in the cavity is high. The cylinder does not require accurate alignment of a resonant cavity. Water droplets having diameters greater than 1 mm have been levitated against the force of gravity using; less than 1 W of input electrical power. Concentration of aerosol particles in air is also demonstrated.

  6. High-concentration tritium sensor

    Energy Technology Data Exchange (ETDEWEB)

    Paglieri, S. N. (Stephen N.); Richmond, S. (Scott); Snow, R. C. (Ronny C.); Morris, J. S. (John S.); Tuggle, D. G. (Dale Glenn)

    2004-01-01

    A bi-layer device was fabricated and tested for the direct collection of electrons emitted by tritium beta decay. The sensor functions at high pressures and concentrations where previously no simple and cost effective direct measurement technique existed for tritium. A polished KOVAR{trademark} (Fe-Ni-Co alloy) rod was coated with a 1-{mu}m thick insulating layer of alumina using electron-beam evaporation, physical vapor deposition (PVD) of aluminum with oxygen dosing. The alumina deposition process was optimized to minimize pinholes and obtain a stable coating with high resistivity. The detector exhibited a nanoampere electrical response over a few decades of tritium concentration, up to pure tritium at 200 kPa. The sensor has been in service for several months now without showing signs of degradation and no discernible physical damage or change in efficiency or linearity has been observed.

  7. High-concentration tritium sensor

    International Nuclear Information System (INIS)

    A bi-layer device was fabricated and tested for the direct collection of electrons emitted by tritium beta decay. The sensor functions at high pressures and concentrations where previously no simple and cost effective direct measurement technique existed for tritium. A polished KOVAR(trademark) (Fe-Ni-Co alloy) rod was coated with a 1-μm thick insulating layer of alumina using electron-beam evaporation, physical vapor deposition (PVD) of aluminum with oxygen dosing. The alumina deposition process was optimized to minimize pinholes and obtain a stable coating with high resistivity. The detector exhibited a nanoampere electrical response over a few decades of tritium concentration, up to pure tritium at 200 kPa. The sensor has been in service for several months now without showing signs of degradation and no discernible physical damage or change in efficiency or linearity has been observed.

  8. Experience in handling concentrated tritium

    International Nuclear Information System (INIS)

    The notes describe the experience in handling concentrated tritium in the hydrogen form accumulated in the Chalk River Nuclear Laboratories Tritium Laboratory. The techniques of box operation, pumping systems, hydriding and dehydriding operations, and analysis of tritium are discussed. Information on the Chalk River Tritium Extraction Plant is included as a collection of reprints of papers presented at the Dayton Meeting on Tritium Technology, 1985 April 30 - May 2

  9. Arsenic concentrations in Chinese coals

    International Nuclear Information System (INIS)

    The arsenic concentrations in 297 coal samples were collected from the main coal-mines of 26 provinces in China were determined by molybdenum blue coloration method. These samples were collected from coals that vary widely in coal rank and coal-forming periods from the five main coal-bearing regions in China. Arsenic content in Chinese coals range between 0.24 to 71 mg/kg. The mean of the concentration of Arsenic is 6.4 ± 0.5 mg/kg and the geometric mean is 4.0 ± 8.5 mg/kg. The level of arsenic in China is higher in northeastern and southern provinces, but lower in northwestern provinces. The relationship between arsenic content and coal-forming period, coal rank is studied. It was observed that the arsenic contents decreases with coal rank in the order: Tertiary > Early Jurassic > Late Triassic > Late Jurassic > Middle Jurassic > Late Permian > Early Carboniferous > Middle Carboniferous > Late Carboniferous > Early Permian; It was also noted that the arsenic contents decrease in the order: Subbituminous > Anthracite > Bituminous. However, compared with the geological characteristics of coal forming region, coal rank and coal-forming period have little effect on the concentration of arsenic in Chinese coal. The average arsenic concentration of Chinese coal is lower than that of the whole world. The health problems in China derived from in coal (arsenism) are due largely to poor local life-style practices in cooking and home heating with coal rather than to high arsenic contents in the coal

  10. REM-containing silicate concentrates

    Science.gov (United States)

    Pavlov, V. F.; Shabanova, O. V.; Pavlov, I. V.; Pavlov, M. V.; Shabanov, A. V.

    2016-01-01

    A new method of advanced complex processing of ores containing rare-earth elements (REE) is proposed to obtain porous X-ray amorphous aluminosilicate material with a stable chemical composition which concentrates oxides of rare-earth metals (REM). The ferromanganese oxide ores of Chuktukon deposit (Krasnoyarsk Region, RF) were used for the experiment. The obtained aluminosilicate material is appropriate for treatment with 5 - 15% solutions of mineral acids to leach REM.

  11. Luminescent solar concentrators employing phycobilisomes

    Energy Technology Data Exchange (ETDEWEB)

    Mulder, Carlijn L.; Theogarajan, Luke; Currie, Michael; Mapel, Jonathan K.; Baldo, Marc A. [Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Vaughn, Michael; Willard, Paul; Bruce, Barry D. [Biochemistry, Cellular and Molecular Biology and Chemical and Biomolecular Engineering University of Tennessee at Knoxville 125 Austin Peay Bldg., Knoxville, TN 37996 (United States); Moss, Mark W.; McLain, Clifford E.; Morseman, John P. [Columbia Biosciences Corporation 6440 Suite D Dobbin Road, Columbia, MD 21045 (United States)

    2009-08-21

    Phycobilisome-based luminescent solar concentrators (LSCs) take advantage of the photosynthetic antenna complexes of red algae and cyanobacteria. The phycobilisomes are successfully stabilized in a solid-state LSC matrix with minimal loss of performance. Comparison of samples with intact and decoupled complexes indicates that energy transfer within intact phycobilisomes results in a reduction of re-absorption losses by {proportional_to}50%. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  12. SQUID With Integral Flux Concentrator

    Science.gov (United States)

    Peters, Palmer N.; Sisk, Robert C.

    1989-01-01

    In improved superconducting quantum interference device (SQUID), change in size and shape of superconducting ring improves coupling to external signal coil and eases coil-positioning tolerances. More rugged and easier to manufacture than conventional SQUID's with comparable electrical characteristics. Thin-film superconducting flux concentrator utilizes Meissner effect to deflect magnetic field of signal coil into central hole of SQUID. Used in magnetometers, ammeters, analog-to-digital converters, and related electronic applications in which high signal-to-noise ratios required.

  13. Processing of rare earth concentrates

    Institute of Scientific and Technical Information of China (English)

    Pamela Alex; R. C. Hubli; A.K. Suri

    2005-01-01

    The paper describes process details for extraction of rare earths from an intermediate grade concentrate of Madhya Pradesh region in India and a South African slag. The xenotime concentrate obtained from the former place was an intermediate grade (47%) rare earth phosphate containing both monazite and xenotime. The South African slag was a low-grade waste product typically containing only 4% of rare earths. The rare earth resource concentrates have been treated individually by different methods such as alkali fusion and alkali leaching to convert them into their mixed oxides. Both types of materials have been processed and greater than 98% solubilization of metal values has been achieved in the intermediate grade xenotime and 80% from the South African slag. The residue of xenotime hydroxide has been washed thoroughly to collect the sodium phosphate, as by-product and the slurry pH have been adjusted to separate rare earths from thorium effectively. Other impurities such as uranium and iron have been removed by precipitation of rare earths by oxalic acid. It has been possible to recover >95% yttrium along with other rare earth oxides.

  14. Photovoltaic concentrator module improvements study

    Energy Technology Data Exchange (ETDEWEB)

    Levy, S.L.; Kerschen, K.A. (Black and Veatch, Kansas City, MO (United States)); Hutchison, G. (Solar Kinetics, Inc., Dallas, TX (United States)); Nowlan, M.J. (Spire Corp., Bedford, MA (United States))

    1991-08-01

    This report presents results of a project to design and fabricate an improved photovoltaic concentrator module. Using previous work as a baseline, this study conducted analyses and testing to select major module components and design features. The lens parquet and concentrator solar cell were selected from the highest performing, available components. A single 185X point-focus module was fabricated by the project team and tested at Sandia. Major module characteristics include a 6 by 4 compression-molded acrylic lens parquet (0.737 m{sup 2} area), twenty-four 0.2 ohms-cm, FZ, p-Si solar cells (1.56 cm{sup 2} area) soldered to ceramic substrates and copper heat spreaders, and an aluminized steel housing with corrugated bottom. This project marked the first attempt to use prismatic covers on solar cells in a high-concentration, point-focus application. Cells with 15 percent metallization were obtained, but problems with the fabrication and placement of prismatic covers on these cells lead to the decision not to use covers in the prototype module. Cell assembly fabrication, module fabrication, and module optical design activities are presented here. Test results are also presented for bare cells, cell assemblies, and module. At operating conditions of 981 watts/m{sup 2} DNI and an estimated cell temperature of 65{degrees}C, the module demonstrated an efficiency of 13.9 percent prior to stressed environmental exposure. 12 refs., 56 figs., 7 tabs.

  15. Coupling leaching of sphalerite concentrate

    Institute of Scientific and Technical Information of China (English)

    彭鹏; 谢惠琴; 卢立柱

    2004-01-01

    Coupling process of sphalerite concentrate leaching in H2 SO4-HNO3 and tetrachloroethylene extracting of sulfur was investigated. Effects of leaching temperature, leaching time, mass ratio of liquid to solid and tetrachloroethylene addition on zinc leaching processes were examined separately. SEM images of sphalerite concentrate and residues were performed by using JEM-6700F field emission scanning electron microscope. The relationship between the number of recycling and extraction ratio of zinc was studied. The results indicate that 99.6 % zinc is obtained after leaching for 3 h at 85 ℃ and pressure of 0.1 MPa O2, with 20 g sphalerite concentrate in 200 mL leaching solution containing 2.0 mol/L H2SO4 and 0.2 mol/L HNO3, in the presence of 10 mL C2Cl4. The leaching time of zinc is 50% shorter than that in the common leaching. The coupling effect is distinct. The recycled C2Cl4 exerts little influence on extraction ratio of zinc.

  16. Liquid radioactive waste concentration methods

    International Nuclear Information System (INIS)

    Methods for concentrating liquid radioactive wastes (LRW) - an important step in waste processing procedures aimed at reducing hazards to personnel and the public - are reviewed, and some of their advantages and drawbacks pointed out. Chemical LRW-treatment methods include coagulation (by aluminium sulfate, ferric chloride, etc.), soda-lime softening of water, as well as techniques based on specific reactions with particular nuclides. By addition of sorbents (clay, activated charcoal, etc.) the chemical scavenging effect is enhanced, while use of flocculating agents (sodium polyalginate, polyacrylamide, synthetic polymers, etc.) produces accelerated deposition of resulting precipitates. A second major LRW-concentration method is evaporation, which is relatively expensive and, moreover, inapplicable in the case of volatile radionuclides escaping into the fume-and-vapor phase. It is emphasized that to overcome difficulties due to presence of contaminants such as saponaceous, organic or mineral oil matter, use of defoaming agents is indicated. A third important LRW-concentration method is that by ion exchange; synthetic is well as natural organic ion exchan.gers are in use. There are a number of other methods that also find application, such as biological techniques, electrodialysis, embedding in bitumen or asphalt, sand filtration, etc. (A.B.)

  17. Radon Concentrations measurements in ENPD

    International Nuclear Information System (INIS)

    Various national and international surveys have demonstrated an increase in radon (222Rn) levels in environment and consequently there is a continuous growing concern about its health effects on the population. Inhalation of indoor radon has long been recognized as a risk to health. The major sources of the indoor radon and its daughters are building materials, natural gas and an underground-derived water supply. In the present work, a set of radon measurements was carried out, using CR-39 solid state nuclear track detector, in different sites in Experimental Nuclear Physics Department (ENPD), Nuclear Research Center (NRC), Atomic Energy Authority (AEA), Egypt. The results showed that the radon concentration and exhalation rate in these sites varied from 10.81 to 264.80 Bq.m-3 and 1.45 to 33.95 mBq.m-2. h-1, respectively. The mean values of radon concentration in meeting rooms, laboratories, stores and bathroom) were 31.211, 198.22, 221.64 and 168.34 Bq.m-3, respectively. The mean values of exhalation rate were (in the same locations) 4, 25, 28.42 and 21.58 mBq.m-2.h-1 respectively. This data showed that stores and laboratories had a significantly higher radon concentration and exhalation rate compared with other rooms.

  18. Citalopram concentrations in samples from autopsies and living persons

    DEFF Research Database (Denmark)

    Worm, Karen; Dragsholt, Claus; Simonsen, Kirsten Wiese;

    1998-01-01

    Retskemi,Citalopram,fatal concentrations,toxic concentrations,therapeutic concentrations,metabolites......Retskemi,Citalopram,fatal concentrations,toxic concentrations,therapeutic concentrations,metabolites...

  19. Light-trapping concentrator cells

    Science.gov (United States)

    Keavney, Christopher J.; Geoffroy, Leo M.; Sanfacon, Michael M.; Tobin, Stephen P.

    1989-11-01

    The objective was to develop a thin, light-trapping silicon concentrator solar cell using a new structure, the cross-grooved cell. A process was developed for fabricating V-grooves on both sides of thin silicon wafers, the grooves on one side being perpendicular to those on the other side. A way to minimize flat spots at the tops of the V-grooves was discovered. The theoretical light-trapping superiority of the cross-grooved structure was verified. A reduction was also demonstrated in grid line obscuration for grid lines running parallel to the V-grooves due to light reflection into the cell. High short-circuit current densities were achieved for p-i-n concentrator cells with the cross-grooved structure, proving the concept. The best efficiencies achieved were 18 percent at concentration, compared to 20 percent for a conventional planar low-resistivity cell. Recombination in the full-area emitter was identified as the major intrinsic loss mechanism in these thin, high-resistivity bifacial cells. Recombination on the emitter limits Voc and fill factor, and also leads to a large sublinearity of short-circuit current with light intensity. Reduction of the junction area is a major recommendation for future work. In addition, there were persistent problems with ohmic contacts and maintaining high minority-carrier lifetime during processing. It is believed that these problems can be solved, and that the cross-grooved cell is a viable approach to the limit-efficiency silicon solar cell. This report covers research conducted between March 1987 and July 1989.

  20. Parabolic dish photovoltaic concentrator development

    Science.gov (United States)

    Beninga, K.; Davenport, R.; Featherby, M.; Sandubrae, J.; Walcott, K.

    1991-05-01

    Science Applications International Corporation (SAIC) and Tactical Fabs, Inc. (TFI) have fabricated a prototype parabolic dish photovoltaic (PV) concentrator system to demonstrate the functionality of this approach. A 1.5 m diameter parabolic dish was fabricated of a polyester/fiberglass composite, with a silvered polymer reflective surface. An innovative receiver cooling system used outward radial flow of cooling water in a narrow passage. This configuration matches the heat transfer capability of the cooling system to the flux profile on the PV receiver, minimizing temperature variations across the receiver. The photovoltaic cells used in the system were a new, TFI-proprietary design. Interleaved contacts form a bi-polar, rear-contact cell configuration. Because the electrical contacts are made on the rear of the cells, cells can be close-packed to form receiver arrays of arbitrary shape and size. Optical testing of the dish concentrator was performed by SAIC, SERI, and Sandia National Labs. The dish concentrator, designed for solar thermal applications, had a tight focal spot but exhibited flux non-uniformities away from the focal plane. Thermal testing of the receiver cooling system was performed with excellent success. Single PV cells, 4-cell blocks, and 144-cell receiver modules were built and tested. The cells successfully demonstrated the TFI design concept, but due to cell processing problems their efficiency was very low. Sources of the processing problems were identified and solutions were proposed, but funding limitations precluded further cell production. Operation of the complete PV dish system was conducted, and the functionality of the system was demonstrated. However, low cell efficiencies and receiver plane flux non-uniformities caused the system performance to be very low. These problems are not generic to the concept, and solutions to them proposed.

  1. Turbulent flow in concentric annuli

    International Nuclear Information System (INIS)

    Fully developed turbulent flow through three concentric annuli was investigated experimentally for a Reynolds-number range Re = 2 x 104 / 2 x 105. Measurements were made of the pressure drop, the positions of zero shear stress and maximum velocity, and the velocity distribution in annuli of radius ratios α = 0.02, 0.04 and 0.1, respectively. The results for the key problem in the flow through annuli, the position of zero shear stress, showed that this position is not coincident with the position of maximum velocity. Furthermore, the investigation showed the strong influence of spacers on the velocity and shear-stress distributions. (orig./TK)

  2. Concentrated photovoltaics, a case study

    Directory of Open Access Journals (Sweden)

    Antonini Piergiorgio

    2014-01-01

    Full Text Available Concentrated Photovoltaics (CPV, once a niche technology, has now reached the maturity and reliability for large scale power generation. Especially in regions where temperatures are very high, the use of high efficiency triple junction solar cells with concentrating optics allows stable energy yield. Thus CPV can be seen as complementary and not in concurrence with silicon photovoltaics. The state of the art, the advantages and limitations of this technology will be shown. Among the main advantages of CPV is the possibility of a much higher energy supply, when compared to silicon photovoltaics, both comparing CPV and silicon with same area or the same installed power. The use of recycled and recyclable materials allows a more environmentally friendly production. The possibility to couple CPV with desalination facilities, energy storage will be analysed. As an example a case study of a CPV installation in Northern Italy is discussed. Here the use of mature technologies, derived from automotive and lighting sectors resulted in a simple and efficient module.

  3. Oxidation Mechanism of Molybdenite Concentrate

    Science.gov (United States)

    Utigard, T.

    2009-08-01

    The oxidation mechanism of a commercial molybdenum concentrate was investigated up to 650 °C using thermal analysis. Upon introduction of air, the molybdenite concentrate started to lose mass due to the oxidation of MoS2 to form molybdenum oxide and SO2. After a rapid mass loss, this was followed by a period of mass gain due to the oxidation of MoO2 to MoO3. The solid-state reaction between MoS2 and MoO3 to form MoO2 was also found to take place. Initially, as air is introduced, the rate is controlled by gas-phase diffusion of oxygen to the reaction surface. With time, as the surfaces of the MoS2 particles become oxidized and the rates start to slow, MoO3 starts to form. This generally leads to a mass gain as well as a slow down in oxidation rate due to the formation of a fairly dense MoO3 product layer. The timing of the various reactions was very dependent on the actual experimental conditions such as sample mass, gas flow rate, and heating rates.

  4. Concentrated photovoltaics, a case study

    Science.gov (United States)

    Antonini, Piergiorgio; Centro, Sandro; Golfetto, Stelvio; Saccà, Alessandro

    2014-12-01

    Concentrated Photovoltaics (CPV), once a niche technology, has now reached the maturity and reliability for large scale power generation. Especially in regions where temperatures are very high, the use of high efficiency triple junction solar cells with concentrating optics allows stable energy yield. Thus CPV can be seen as complementary and not in concurrence with silicon photovoltaics. The state of the art, the advantages and limitations of this technology will be shown. Among the main advantages of CPV is the possibility of a much higher energy supply, when compared to silicon photovoltaics, both comparing CPV and silicon with same area or the same installed power. The use of recycled and recyclable materials allows a more environmentally friendly production. The possibility to couple CPV with desalination facilities, energy storage will be analysed. As an example a case study of a CPV installation in Northern Italy is discussed. Here the use of mature technologies, derived from automotive and lighting sectors resulted in a simple and efficient module.

  5. Burnable gas concentration control system

    International Nuclear Information System (INIS)

    In a combustion gas concentration control system, the height from the upper end of a catalyst to an exit of a chimney is determined to twice or more the height of the catalyst, and the flow area of the exit of the chimney is determined to 25% or more of the flow rate area at the entrance of the chimney. Alternatively, a cover is formed above the exit of the chimney, the height from the upper end of the catalyst to the exit of the chimney is determined to three times or more the height of the catalyst, and the ratio between the flow channel area at a gap portion between the cover and the exit of the chimney and the flow channel area of the entrance of the chimney is determined to 60% or more. The area of the cover is made greater than the flow channel area at the exit of the chimney, and the area of the floor below the chimney is made greater than the cross sectional area at the lower portion of the chimney. In addition, a burnable gas concentration reducing device is disposed near a living body shielding walls and near the inner wall of a pressure suppression chamber. Burnable gases can be processed efficiently upon occurrence of an accident. (N.H.)

  6. Technology Roadmaps: Concentrating Solar Power

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    The emerging technology known as concentrating solar power, or CSP, holds much promise for countries with plenty of sunshine and clear skies. Its electrical output matches well the shifting daily demand for electricity in places where airconditioning systems are spreading. When backed up by thermal storage facilities and combustible fuel, it offers utilities electricity that can be dispatched when required, enabling it to be used for base, shoulder and peak loads. Within about one to two decades, it will be able to compete with coal plants that emit high levels of CO2. The sunniest regions, such as North Africa, may be able to export surplus solar electricity to neighbouring regions, such as Europe, where demand for electricity from renewable sources is strong. In the medium-to-longer term, concentrating solar facilities can also produce hydrogen, which can be blended with natural gas, and provide low-carbon liquid fuels for transport and other end-use sectors. For CSP to claim its share of the coming energy revolution, concerted action is required over the next ten years by scientists, industry, governments, financing institutions and the public. This roadmap is intended to help drive these indispensable developments.

  7. Congestion management utilizing concentric relaxation

    Directory of Open Access Journals (Sweden)

    Škokljev Ivan

    2007-01-01

    Full Text Available In the market-oriented power system environment, congestion management is a novel term connoting the power system steady state security functions. A large number of transmission transactions are dispatched in the regional day-ahead market and traverse the network adding to the power flow loading of the grid elements. Congestion is defined as a network security limit violation prospective due to transactions. Congestion management is a set of measures aimed at solving the congestion problem. This paper devises the concentric relaxation assisted approach to open access transmission network congestion management. The DC load flow symbolic simulator generates line power transfer functions. Congestion management is a systematic procedure based on linear programming. The DC load flow symbolic simulator generates all constraints and the black-box optimization library function is used to solve the problem of congestion on a sample IEEE RTS power system.

  8. Freeze concentration of lime juice

    Directory of Open Access Journals (Sweden)

    Ampawan Tansakul

    2008-11-01

    Full Text Available The main objective of this research was to study the effects of processing conditions, i.e. cooling medium temperature (-6, -12 and -18C and scraper blade rotational speed (50, 100 and 150 rpm on the freeze concentration of lime juice. The initial soluble solid content of lime juice was 7.6 Brix. Results showed that soluble solid content of lime juice increased as cooling medium temperature decreased while scraper blade rotational speed increased. It was also found that the processing condition with -18˚C cooling medium temperature and 150 rpm rotational speed of the scraper blade was the best among all studied conditions, although the loss of the soluble solids with ice crystals during ice separation was relatively high at 35%.

  9. Radon Concentration Intercomparison in Serbia

    International Nuclear Information System (INIS)

    According to Law on Ionizing Radiation Protection and on Nuclear Safety radioactivity testing in Serbia may be performed only by accredited laboratories. Accredited laboratories ought to participate in interlaboratory comparison or proficiency-testing programme for each accredited method. The participants in radon concentration intercomparison in 2012 in Serbia were three laboratories. The laboratories are practicing the same method for radon measurement using charcoal canisters US EPA protocol 520/5-87-005, 1987. The results of intercomparison were evaluated by using the u-test which was calculated according to the IAEA criteria. Measurements with u-score lower than or equal to 2.58 are considered acceptable. Eight canisters were exposed at two sites in Vinèa Institute, four canisters were used in each location simultaneously. Exposure times were between 2 and 3 days. Difference in masses before and after exposure was measured in order to perform the correction for humidity. Standard and background canisters are used for the calibration of the measurement equipment. Standard canister is a sealed canister with the same matrix and geometry as the canisters used for measurements, but with the known activity of radon. All eight charcoal canisters were measured in all three participating laboratories on HP Ge detectors. Each laboratory corrects the results with calibration factor and with adjustment factor obtained from canisters manufacturer. The activities of radon concentrations were calculated independently. From the comparison of the performance of these 3 laboratories, it can be seen that all of them had an excellent performance in this intercomparison, which indicates the stability of the performance of the analytical systems in these laboratories.(author)

  10. The concentration of retail in Poland

    Directory of Open Access Journals (Sweden)

    Michał Gazdecki

    2010-01-01

    Full Text Available The article discusses the processes of concentration taking place in retail in Poland. In spite of strong concentration processes, which took place after 2000, Poland still remains a country of dispersed retail structure. In the nearest years we can expect capital concentration (mainly takeovers in modern trade and contract concentration (for example, merchants’ societies in traditional trade.

  11. The distribution of Radon concentration in caves.

    OpenAIRE

    Cigna Arrigo A.

    2003-01-01

    Radon concentration in caves is known to vary within an extremely wide range. Here the distribution of the average values of radon concentration is examined and a power law describing is identified, i.e. radon concentration has a fractal dimension D=1.26. This fact means that concentrations are not grouped around a mean value, a characteristic common to many other phenomena.

  12. Analysis of Photovoltaic Concentrating Solar Energy Systems

    OpenAIRE

    Garo Pilawjian

    2012-01-01

    In this paper the photovoltaic concentrating solar energy systems are analyzed. Both the Fresnel lens light refraction and mirror light reflection concentrating optical systems are considered. The main parameters and properties of photovoltaic concentrating solar energy systems are outlined. It is shown that the multi-parameter cost optimization is necessary to conduct to reduce the cost of photovoltaic concentrating solar energy systems.

  13. Chloride sublimation of gold-arsenic concentrates

    International Nuclear Information System (INIS)

    Present article is devoted to chloride sublimation of gold-arsenic concentrates. The results of studies of chloride sublimation of gold-arsenic comprising concentrates of Chore deposit of Tajikistan are considered. It is found that by application sodium chloride for gold-arsenic comprising concentrates it is possible to extract gold and silver from flotation concentrates.

  14. Concentrators Enhance Solar Power Systems

    Science.gov (United States)

    2013-01-01

    "Right now, solar electric propulsion is being looked at very seriously," says Michael Piszczor, chief of the photovoltaic and power technologies branch at Glen Research Center. The reason, he explains, originates with a unique NASA mission from the late 1990s. In 1998, the Deep Space 1 spacecraft launched from Kennedy Space Center to test a dozen different space technologies, including SCARLET, or the Solar Concentrator Array with Refractive Linear Element Technology. As a solar array that focused sunlight on a smaller solar cell to generate electric power, SCARLET not only powered Deep Space 1 s instruments but also powered its ion engine, which propelled the spacecraft throughout its journey. Deep Space 1 was the first spacecraft powered by a refractive concentrator design like SCARLET, and also utilized multi-junction solar cells, or cells made of multiple layers of different materials. For the duration of its 38-month mission, SCARLET performed flawlessly, even as Deep Space 1 flew by Comet Borrelly and Asteroid Braille. "Everyone remembers the ion engine on Deep Space 1, but they tend to forget that the SCARLET array powered it," says Piszczor. "Not only did both technologies work as designed, but the synergy between the two, solar power and propulsion together, is really the important aspect of this technology demonstration mission. It was the first successful use of solar electric propulsion for primary propulsion." More than a decade later, NASA is keenly interested in using solar electric propulsion (SEP) for future space missions. A key issue is cost, and SEP has the potential to substantially reduce cost compared to conventional chemical propulsion technology. "SEP allows you to use spacecraft that are smaller, lighter, and less costly," says Piszczor. "Even though it might take longer to get somewhere using SEP, if you are willing to trade time for cost and smaller vehicles, it s a good trade." Potentially, SEP could be used on future science missions

  15. Concentrating Solar Power. Technology Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-10-15

    Concentrating solar power can contribute significantly to the world's energy supply. As shown in this roadmap, this decade is a critical window of opportunity during which CSP could become a competitive source of electrical power to meet peak and intermediate loads in the sunniest parts of the world. This roadmap identifies technology, economy and policy goals and milestones needed to support the development and deployment of CSP, as well as ongoing advanced research in CSF. It also sets out the need for governments to implement strong, balanced policies that favour rapid technological progress, cost reductions and expanded industrial manufacturing of CSP equipment to enable mass deployment. Importantly, this roadmap also establishes a foundation for greater international collaboration. The overall aim of this roadmap is to identify actions required - on the part of all stakeholders - to accelerate CSP deployment globally. Many countries, particularly in emerging regions, are only just beginning to develop CSP. Accordingly, milestone dates should be considered as indicative of urgency, rather than as absolutes. This roadmap is a work in progress. As global CSP efforts advance and an increasing number of CSP applications are developed, new data will provide the basis for updated analysis. The IEA will continue to track the evolution of CSP technology and its impacts on markets, the power sector and regulatory environments, and will update its analysis and set additional tasks and milestones as new learning comes to light.

  16. Summary of Dissolved Concentration Limits

    Energy Technology Data Exchange (ETDEWEB)

    Yueting Chen

    2001-06-11

    According to the Technical Work Plan titled Technical Work Plan for Waste Form Degradation Process Model Report for SR (CRWMS M&O 2000a), the purpose of this study is to perform abstractions on solubility limits of radioactive elements based on the process-level information and thermodynamic databases provided by Natural Environment Program Operations (NEPO) and Waste Package Operations (WPO). The scope of this analysis is to produce solubility limits as functions, distributions, or constants for all transported radioactive elements identified by the Performance Assessment Operations (PAO) radioisotope screening. Results from an expert elicitation for solubility limits of most radioactive elements were used in the previous Total System Performance Assessments (TSPAs). However, the elicitation conducted in 1993 does not meet the criteria set forth by the U.S. Nuclear Regulatory Commission (NRC) due to lack of documentation and traceability (Kotra et al. 1996, Section 3). Therefore, at the Waste Form Abstraction Workshop held on February 2-4, 1999, at Albuquerque, New Mexico, the Yucca Mountain Site Characterization Project (YMP) decided to develop geochemical models to study solubility for the proposed Monitored Geologic Repository. WPO/NEPO is to develop process-level solubility models, including review and compilation of relevant thermodynamic data. PAO's responsibility is to perform abstractions based on the process models and chemical conditions and to produce solubility distributions or response surfaces applicable to the proposed repository. The results of this analysis and conceptual model will feed the performance assessment for Total System Performance Assessment--Site Recommendation (TSPA-SR) and Total System Performance Assessment--License Application (TSPA-LA), and to the Waste Form Degradation Process Model Report section on concentration limits.

  17. 2011 NATA - Risks and Annual Ambient Concentrations

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset includes the modeled annual ambient concentrations and risks at the census tract level for the 2011 National Air Toxics Assessment. All concentrations...

  18. Medical Oxygen Concentrator for Microgravity Operation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We have all seen people carrying portable oxygen tanks or concentrators to provide critical life support respiratory oxygen. Heavy, bulky, and for O2 concentrators,...

  19. Inorganic sorbents for concentration of hydrogen sulfide

    International Nuclear Information System (INIS)

    Present work is devoted to application of inorganic sorbents for concentration of hydrogen sulfide. The elaboration of method is conducted under controlled concentrations of hydrogen sulphide from 1.00 til 0.01 mg/l.

  20. Aztreonam concentrations in human prostatic tissue.

    OpenAIRE

    Madsen, P O; Dhruv, R; Friedhoff, L T

    1984-01-01

    The concentrations of aztreonam in human prostatic tissue specimens obtained by transurethral resection were measured in nine patients after the intramuscular administration of a single 1-g dose. The average concentration of aztreonam was 7.8 microgram/g of prostate between 50 and 180 min after dosage. The average ratio of the drug concentration in prostate to that in serum was 0.25. The concentrations of aztreonam achieved were significantly higher than the MICs for most members of the famil...

  1. The concentration of poverty within metropolitan areas

    OpenAIRE

    Aliprantis, Dionissi; Fee, Kyle; Oliver, Nelson

    2013-01-01

    Not only has poverty recently increased in the United States, it has also become more concentrated. This Commentary documents changes in the concentration of poverty in metropolitan areas over the last decade. The analysis shows that the concentration of poverty tends to be highest in northern cities, and that wherever overall poverty or unemployment rates went up the most over the course of the decade, the concentration of poverty tended to increase there as well.

  2. Spatial Point Pattern Analysis and Industry Concentration

    OpenAIRE

    Kosfeld, Reinhold; Eckey, Hans-Friedrich; Lauridsen, Jørgen

    2009-01-01

    Traditional measures of spatial industry concentration are restricted to given areal units. They do not make allowance for the fact that concentration may be differently pronounced at various geographical levels. Methods of spatial point pattern analysis allow to measure industry concentration at a continuum of spatial scales. While common distance based methods are well applicable for sub-national study areas, they become inefficient in measuring concentration at various levels within indust...

  3. Analysis of Photovoltaic Concentrating Solar Energy Systems

    Directory of Open Access Journals (Sweden)

    Garo Pilawjian

    2012-03-01

    Full Text Available In this paper the photovoltaic concentrating solar energy systems are analyzed. Both the Fresnel lens light refraction and mirror light reflection concentrating optical systems are considered. The main parameters and properties of photovoltaic concentrating solar energy systems are outlined. It is shown that the multi-parameter cost optimization is necessary to conduct to reduce the cost of photovoltaic concentrating solar energy systems.

  4. Probiotic Yoghurts From Ultrafiltered Concentrated Milk

    OpenAIRE

    Kozludzhova Siyka; Goranov Bogdan; Boyanova Petya; Yanakieva Velichka; Dushkova Mariya; Dinkov Kolyo

    2015-01-01

    In this paper, yoghurts from ultrafiltered concentrated whole milk with a volume reduction ratio 0, 2 and 3 with three different probiotic yoghurt starters were obtained. Their physiological, microbiological and rheological properties were examined. The concentrated probiotic yoghurts had high concentration of viable cells of the probiotic strain Lactobacillus delbrueckii ssp. bulgaricus (over 1010cfu/cm3). For the preparation of concentrated probiotic yoghurts the most appropriate volume red...

  5. 21 CFR 131.115 - Concentrated milk.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Concentrated milk. 131.115 Section 131.115 Food... HUMAN CONSUMPTION MILK AND CREAM Requirements for Specific Standardized Milk and Cream § 131.115 Concentrated milk. (a) Description. Concentrated milk is the liquid food obtained by partial removal of...

  6. Executive Compensation Concentration and Institutional Ownership Power

    OpenAIRE

    Wei Li; Tingting Guo

    2015-01-01

    In this paper, we examine whether institutional shareholders prefer concentrated or dispersed executive compensation structure. To address this question, we study the relationship between executive compensation concentration and institutional ownership power because institutional investors can influence executive compensation more when they have more power. We measure institutional ownership power using institutional ownership level and institutional ownership concentration. We find a signifi...

  7. Color corrected Fresnel lens for solar concentration

    International Nuclear Information System (INIS)

    A new linear convex Fresnel lens with its groove side down is described. The design philosophy is similar to the highly concentrating two focal Fresnel lens but including a correction for chromatic aberration. A solar concentration ratio as high as 80 is achieved. For wide acceptance angles the concentration nears the theoretical maximum. (author)

  8. Effects of concentrated sunlight on organic photovoltaics

    DEFF Research Database (Denmark)

    Tromholt, Thomas; Katz, Eugene A.; Hirsch, Baruch;

    2010-01-01

    We report the effects of concentrated sunlight on key photovoltaic parameters and stability of organic photovoltaics (OPV). Sunlight collected and concentrated outdoors was focused into an optical fiber and delivered onto a 1 cm2 bulk-heterojunction cell. Sunlight concentration C was varied...

  9. Dense-array concentrator photovoltaic system using non-imaging dish concentrator and crossed compound parabolic concentrator

    Science.gov (United States)

    Chong, Kok-Keong; Yew, Tiong-Keat; Wong, Chee-Woon; Tan, Ming-Hui; Tan, Woei-Chong; Lai, An-Chow; Lim, Boon-Han; Lau, Sing-Liong; Rahman, Faidz Abdul

    2015-04-01

    Solar concentrating device plays an important role by making use of optical technology in the design, which can be either reflector or lens to deliver high flux of sunlight onto the Concentrator Photovoltaic (CPV) module receiver ranging from hundreds to thousand suns. To be more competitive compared with fossil fuel, the current CPV systems using Fresnel lens and Parabolic dish as solar concentrator that are widely deployed in United States, Australia and Europe are facing great challenge to produce uniformly focused sunlight on the solar cells as to reduce the cost of electrical power generation. The concept of non-imaging optics is not new, but it has not fully explored by the researchers over the world especially in solving the problem of high concentration solar energy, which application is only limited to be a secondary focusing device or low concentration device using Compound Parabolic Concentrator. With the current advancement in the computer processing power, we has successfully invented the non-imaging dish concentrator (NIDC) using numerical simulation method to replace the current parabolic dish as primary focusing device with high solar concentration ratio (more than 400 suns) and large collective area (from 25 to 125 m2). In this paper, we disclose our research and development on dense array CPV system based on non-imaging optics. The geometry of the NIDC is determined using a special computational method. In addition, an array of secondary concentrators, namely crossed compound parabolic concentrators, is also proposed to further focus the concentrated sunlight by the NIDC onto active area of solar cells of the concentrator photovoltaic receiver. The invention maximizes the absorption of concentrated sunlight for the electric power generation system.

  10. MARKET CONCENTRATION IN TURKISH JOURNALISM SECTOR

    Directory of Open Access Journals (Sweden)

    ADEM KALÇA

    2013-05-01

    Full Text Available Concentration is a situation in which market structure of a sector is controlled by a few firms. At the present time, many analyzing methods such as Herfindahl-Hirschman and N-Firm Concentration Indexes are used to determine market structure.According to market concentration indexes, higher concentration level means more monopolistic market structure, lower concentration level means more full competitive market structure. In this study concentration levels of media groups in Turkish journalism sector within the scope of traditional journalism and internet journalism was analyzed via N-Firm Concentration and H-H Indexes. As a result of the study, it’s seen that first four biggest media groups have monopolistic competition in internet journalism sector,and oligopol structure in traditional journalism sector. According to H-H index analyze, there is monopolistic competition in the sector.

  11. Metamaterial anisotropic flux concentrators and magnetic arrays

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Smith, Anders; Bahl, Christian R.H.

    2013-01-01

    A metamaterial magnetic flux concentrator is investigated in detail in combination with a Halbach cylinder of infinite length. A general analytical solution to the field is determined and the magnetic figure of merit is determined for a Halbach cylinder with a flux concentrator. It is shown that an...... ideal flux concentrator will not change the figure of merit of a given magnet design, while the non-ideal will always lower it. The geometric parameters producing maximum figure of merit, i.e., the most efficient devices, are determined. The force and torque between two concentric Halbach cylinders with...... flux concentrators is determined and the maximum torque is found. Finally, the effect of non-ideal flux concentrators and the practical use of flux concentrators, as well as demagnetization issues, is discussed. © 2013 AIP Publishing LLC....

  12. Concentration factors - Their use and abuse

    International Nuclear Information System (INIS)

    This report examines the use of concentration factors as an index of an aquatic organism's ability to concentrate constituents in its environment. The values of concentration factors can vary considerably depending on the method of their measurement. A 'true' concentration factor can be approximated by determining the ratio of the stable element concentration in a representative population to that of a representative water sample, or by determining the radionuclide concentration factor of a population in equilibrium with its biological exchangeable pool. Before concentration factors are used for the assessment of radioactive contamination of food chains, the method of measurement should be examined carefully to ascertain whether they are applicable to the situation under consideration. (author)

  13. Aqueous uranium concentrations in the natural environment

    International Nuclear Information System (INIS)

    Published geochemical data from groundwater and surface water throughout the world has been compiled in order to compare the concentration of naturally occurring dissolved uranium to lithology, sampling depth, pH, Eh, HCO3, SO4 and PO4 concentrations. The sole criterion used for the selection of data from the review articles was that each article contain raw data on naturally occurring uranium concentrations relative to other groundwater chemical components. A total of 1286 chemical data entries were used in the statistical comparisons. Although this database is not exhaustive, it is likely that the ranges of uranium concentrations in the data set are representative of the ranges occurring in nature. Finally, the observed uranium concentration distributions were compared with published results of model calculations and of used nuclear fuel leach tests. Models tend to predict a wider range of concentrations than observed (particularly the high values), and the leach test concentrations tend to fall within the upper half of the observations

  14. Heavy Metal Concentrations in Maltese Potable Water

    Directory of Open Access Journals (Sweden)

    Roberta Bugeja

    2015-05-01

    Full Text Available This study evaluates the levels of aluminum (Al, cadmium (Cd, chromium (Cr, copper (Cu, iron (Fe, lead (Pb, nickel (Ni and zinc (Zn in tap water samples of forty localities from around the Maltese Islands together with their corresponding service supply reservoirs. The heavy metal concentrations obtained indicated that concentrations of the elements were generally below the maximum allowed concentration established by the Maltese legislation. In terms of the Maltese and EU water quality regulations, 17.5% of the localities sampled yielded water that failed the acceptance criteria for a single metal in drinking water. Higher concentrations of some metals were observed in samples obtained at the end of the distribution network, when compared to the concentrations at the source. The observed changes in metal concentrations between the localities’ samples and the corresponding supply reservoirs were significant. The higher metal concentrations obtained in the samples from the localities can be attributed to leaching in the distribution network.

  15. Linear Fresnel concentrators for building integrated applications

    International Nuclear Information System (INIS)

    In this paper an exhaustive study of a stationary wide angle Fresnel lens combined with a moving compound parabolic concentrator to track the Sun during the year is presented. The concentrating optical systems is proposed for building integrated solar applications. In the first section, the sensitivity analysis of design key parameters and its relationships is addressed. The parameters under study are the lens curvature, the maximum concentration and the compactness or the related aspect ratio. In the second section, it is concluded that a concentration ratio of 12.5 suns is the optimum geometric concentration for the Fresnel lens to satisfy both architectural features and solar concentration requirements. In the third section, the combination of the optimum Fresnel two compound parabolic concentrator designs is evaluated. The deep analysis of the optical system presented offers useful results for future designers.

  16. Lubricant additive concentrate containing isomerized jojoba oil

    Energy Technology Data Exchange (ETDEWEB)

    Arndt, G.

    1987-05-12

    This patent describes a crankcase motor oil additive concentrate intended to be added to a conventional crankcase motor oil to improve its ability to lubricate and protect the engine. The additive concentrate comprises the following components: A petroleum base stock of lubricating quality and viscosity. The base stock comprises from about 13.5 to 90 weight percent of the additive concentrate; a detergent-inhibitor package. The package is present at from about 7 to about 40 weight percent of the concentrate; a supplemental antiwear additive selected from the salts of dialkyl dithiophosporic acids. The additive is present at a level of from about 1 to about 10 weight percent of the concentrate; and a supplemental antiwear additive selected from the class of sulfurized olefins. The additive is present at a level of from about 1 to about 10 weight percent of the concentrate.

  17. Causality Between Urban Concentration and Environmental Quality

    Directory of Open Access Journals (Sweden)

    Amin Pujiati

    2015-08-01

    Full Text Available Population is concentrated in urban areas can cause the external diseconomies on environment if it exceeds the carrying capacity of the space and the urban economy. Otherwise the quality of the environment is getting better, led to the concentration of population in urban areas are increasingly high. This study aims to analyze the relationship of causality between the urban concentration and environmental quality in urban agglomeration areas. The data used in the study of secondary data obtained from the Central Bureau of statistics and the City Government from 2000 to 2013. The analytical method used is the Granger causality and descriptive. Granger causality study results showed no pattern of reciprocal causality, between urban concentration and the quality of the environment, but there unidirectional relationship between the urban concentration and environmental quality. This means that increasing urban concentration led to decreased environmental quality.

  18. Plasma concentrations of voriconazole in falcons.

    Science.gov (United States)

    Schmidt, V; Demiraj, F; Di Somma, A; Bailey, T; Ungemach, F R; Krautwald-Junghanns, M-E

    2007-08-25

    Doses of 12.5 mg voriconazole/kg bodyweight administered every 12 hours by crop gavage to six falcons for 14 days provided peak plasma concentrations of more than 1 microg/ml, but the trough concentrations were lower and sometimes undetectable. Administering the same doses incorporated into meat that was fed to one falcon for seven days and to three falcons for up to 91 days provided similar plasma concentrations. PMID:17720963

  19. The Price-Concentration Relationship in Banking.

    OpenAIRE

    Berger, Allen N.; Timothy H. Hannan

    1989-01-01

    The commonly observed positive correlation between market concentration and profitability may be explained by noncompetitive pricing behavior, as argued by the structure-performance hypothesis, or by the greater efficiency of firms with dominant market shares, as argued by the efficient-structure hypothesis. By examining the price-concentration relationship instead of the profit-concentration relationship, this paper tests the structure-performance hypothesis in a manner that excludes the eff...

  20. Optimal concentration for sugar transport in plants

    OpenAIRE

    Jensen, Kaare H.; Savage, Jessica A.; HOLBROOK, N. MICHELE

    2013-01-01

    Vascular plants transport energy in the form of sugars from the leaves where they are produced to sites of active growth. The mass flow of sugars through the phloem vascular system is determined by the sap flow rate and the sugar concentration. If the concentration is low, little energy is transferred from source to sink. If it is too high, sap viscosity impedes flow. An interesting question is therefore at which concentration is the sugar flow optimal. Optimization of sugar flow and transpor...

  1. A statistical proxy for sulphuric acid concentration

    OpenAIRE

    S. Mikkonen; S. Romakkaniemi; J. N. Smith; Korhonen, H.; Petäjä, T.; Plass-Duelmer, C.; M. Boy; P. H. McMurry; Lehtinen, K. E. J.; Joutsensaari, J.; Hamed, A.(Texas A&M University, College Station, TX, 77843, USA); R. L. Mauldin III; Birmili, W.; Spindler, G; Arnold, F.

    2011-01-01

    Gaseous sulphuric acid is a key precursor for new particle formation in the atmosphere. Previous experimental studies have confirmed a strong correlation between the number concentrations of freshly formed particles and the ambient concentrations of sulphuric acid. This study evaluates a body of experimental gas phase sulphuric acid concentrations, as measured by Chemical Ionization Mass Spectrometry (CIMS) during six intensive measurement campaigns and one long-term observational period. The...

  2. Solar concentrators with adjustable power density distributions

    Energy Technology Data Exchange (ETDEWEB)

    Kleinwaechter, J.

    1977-09-01

    Solar concentrators are described which provide given power density in the absorber. According to the invention, 'semi-optical' lenses and mirrors are used to concentrate the incident solar radiation; these elements image the solar disk not as a point but as an area of constant illumination intensity on the absorber. This is achieved by a functional locus-dependecy of refraction and reflection. For mirror concentration, a differential equation is given which satisfies this functional dependency.

  3. Concentration of 'forgotten' substances using the XAD concentration method. Suitability of the method for hydrophilic chemicals

    NARCIS (Netherlands)

    Collombon MT; LER

    2007-01-01

    Concentration of forgotten substances using the XAD concentration method In the nineties, RIVM developed a method to concentrate toxic substances on XAD (a synthetic resin). Using bioassays, the toxicity can be determined in the concentrate. 'Modern' toxic substances tend to be more polar then 'clas

  4. Air Force concentrating photovoltaic array program

    International Nuclear Information System (INIS)

    A summary is given of Air Force solar concentrator projects beginning with the Rockwell International study program in 1977. The Satellite Materials Hardening Programs (SMATH) explored and developed techniques for hardening planar solar cell array power systems to the combined nuclear and laser radiation threat environments. A portion of program dollars was devoted to developing a preliminary design for a hardened solar concentrator. The results of the Survivable Concentrating Photovoltaic Array (SCOPA) program, and the design, fabrication and flight qualification of a hardened concentrator panel are discussed

  5. Tritium concentrations in tree ring cellulose

    International Nuclear Information System (INIS)

    Measurements of tritium (tissue bound tritium; TBT) concentration in tree rings are presented and discussed. Such measurement is expected to provide a useful means of estimating the tritium level in the environment in the past. The concentration of tritium bound in the tissue (TBT) in a tree ring considered to reflect the environmental tritium level in the area at the time of the formation of the ring, while the concentration of tritium in the free water in the tissue represents the current environmental tritium level. First, tritium concentration in tree ring cellulose sampled from a cedar tree grown in a typical environment in Fukuoka Prefecture is compared with the tritium concentration in precipitation in Tokyo. Results show that the year-to-year variations in the tritium concentration in the tree rings agree well with those in precipitation. The maximum concentration, which occurred in 1963, is attibuted to atmospheric nuclear testing which was performed frequently during the 1961 - 1963 period. Measurement is also made of the tritium concentration in tree ring cellulose sampled from a pine tree grown near the Isotope Center of Kyushu University (Fukuoka). Results indicate that the background level is higher probably due to the release of tritium from the facilities around the pine tree. Thus, measurement of tritium in tree ring cellulose clearly shows the year-to-year variation in the tritium concentration in the atmosphere. (N.K.)

  6. Horizontally staggered lightguide solar concentrator with lateral displacement tracking for high concentration applications.

    Science.gov (United States)

    Ma, Hongcai; Wu, Lin

    2015-07-10

    We present the design of a horizontally staggered lightguide solar concentrator with lateral displacement tracking for high concentration applications. This solar concentrator consists of an array of telecentric primary concentrators, a horizontally staggered lightguide layer, and a vertically tapered lightguide layer. The primary concentrator is realized by two plano-aspheric lenses with lateral movement and maintains a high F-number over an angle range of ±23.5°. The results of the simulations show that the solar concentrator achieves a high concentration ratio of 500× with ±0.5° of acceptance angle by a single-axis tracker and dual lateral translation stages. PMID:26193396

  7. Status of concentrator collector and high-efficiency concentrator cell development

    Energy Technology Data Exchange (ETDEWEB)

    Gee, J.M.

    1990-01-01

    Photovoltaic concentrator collectors are an attractive option for utility-scale photovoltaic power plants. This paper reviews the current status of photovoltaic concentrator collector and cell development. Included in the review is a discussion of the economic motivation for concentrators, a summary of recent concentrator collector and cell development, and a description of a major new program to accelerate development and commercial introduction of concentrator collectors. 21 refs., 1 fig., 3 tabs.

  8. Measurements of natural 41Ca concentrations

    International Nuclear Information System (INIS)

    Atomic mass spectroscopic examinations on 41Ca were carried out in the UNILAC accelerator. A sensitivity of about 10-15 was achieved. This would allow the measurement of present natural 41Ca concentrations as soon as the problem of the transmission determination is solved. In this respect suggestions were worked out and their feasibility discussed. The detection of 41Ca-ions is especially free of background when high UNILAC-energies are applied. An estimation showed a background level corresponding with a 41Ca concentration of less then 10-17 referred to 40Ca. Besides an independent concept for the electromagnetic concentration of 41Ca with variable concentration factors was developed. After being concentrated up to 50 respectively 25 times the initial concentration in the GSI mass separator, the 41Ca concentration of three recent deer bones found in the Odenwald was measured by atomic mass spectroscopy in the 14UD-Pelletron Tandem in Rehovot (Israel). The measured 41Ca concentrations ranged between 10-14 to 10-13 with consideration of the concentration factor. A theoretical study of the 41Ca production in the earth's surface based on cosmic radiation illustrates the influence of trace elements on the neutron flux and thus on the 41Ca production. This influence might be a possible explanation for the observed amplitude of variation of the 41Ca concentration in recent bones which are of decisive importance for the feasibility of 41Ca-related dating. In this work a method is suggested that does not depend on the amplitude of variation mentioned above and which would allow the determination of the erosion rate of rocks by its 41Ca concentrations. (orig./HP)

  9. EXPERIMENTAL STUDIES ON FELDSPAR ORE CONCENTRATION

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A series of Fe2O3-elimination experiments were conducted on feldspar samples from Tangshan Stone-powder Plant. These experimental methods include scrubbing desliming, flotation, rod milling and high gradient magnetic separation. Some technical factors of feldspar concentration and a new technological flow-sheet of ceramics raw material concentration were put forward.

  10. Plutonium concentrations in forest fire smoke plumes

    International Nuclear Information System (INIS)

    Air filter samples from four forest logging slash burns were analyzed for plutonium. Although airborne concentrations were low, one fire definitely released fallout plutonium since the measured concentration in the smoke was one order of magnitude greater than ambient background measured upwind the same day

  11. Solar refractive secondary concentrator technology overview

    International Nuclear Information System (INIS)

    Refractive secondary concentrators, coupled with advanced primary concentrators, can efficiently convert solar energy to heat for a wide variety of space applications including power generation, thermal propulsion, and furnaces. These applications typically require very high temperatures (as high as 2000 K) and high concentration ratios (10,000 to 1). To enable concentration systems that meet these requirements, the NASA Glenn Research Center is developing the refractive secondary concentrator, which uses refraction and total internal reflection to concentrate and direct solar energy. Presented is an overview of the refractive secondary concentrator technology development effort, including a description of benefits, past accomplishments, and future plans. Highlighted is a recent proof-of-concept test of a prototype sapphire refractive secondary concentrator performed in a solar vacuum environment that demonstrated throughput efficiency of 87%. It is anticipated that the application of an optical coating to the inlet surface of the refractive secondary to reduce the reflection losses at this surface can improve the throughput efficiency to 93%. Plans to conduct additional solar thermal vacuum tests to demonstrate high temperatures and high throughput power are also presented (up to 2000 K and 5 kW)

  12. Refractive Secondary Concentrators for Solar Thermal Applications

    Science.gov (United States)

    Wong, Wayne A.; Macosko, Robert P.

    1999-01-01

    The NASA Glenn Research Center is developing technologies that utilize solar energy for various space applications including electrical power conversion, thermal propulsion, and furnaces. Common to all of these applications is the need for highly efficient, solar concentration systems. An effort is underway to develop the innovative single crystal refractive secondary concentrator, which uses refraction and total internal reflection to efficiently concentrate and direct solar energy. The refractive secondary offers very high throughput efficiencies (greater than 90%), and when used in combination with advanced primary concentrators, enables very high concentration ratios (10,0(X) to 1) and very high temperatures (greater than 2000 K). Presented is an overview of the refractive secondary concentrator development effort at the NASA Glenn Research Center, including optical design and analysis techniques, thermal modeling capabilities, crystal materials characterization testing, optical coatings evaluation, and component testing. Also presented is a discussion of potential future activity and technical issues yet to be resolved. Much of the work performed to date has been in support of the NASA Marshall Space Flight Center's Solar Thermal Propulsion Program. The many benefits of a refractive secondary concentrator that enable efficient, high temperature thermal propulsion system designs, apply equally well to other solar applications including furnaces and power generation systems such as solar dynamics, concentrated thermal photovoltaics, and thermionics.

  13. Electrochemical phosphate recovery from nanofiltration concentrates

    NARCIS (Netherlands)

    Kappel, C.; Yasadi, K.; Temmink, B.G.; Metz, S.J.; Kemperman, A.J.B.; Nijmeijer, K.; Zwijnenburg, A.; Witkamp, G.J.; Rijnaarts, H.

    2013-01-01

    The high total phosphorus content of raw domestic wastewater with its significant eutrophication potential offers an excellent possibility for phosphate recovery. Continuous recirculation of NF concentrate to an MBR and simultaneous phosphate recovery from the NF concentrate can be applied to produc

  14. Market power, industrial concentration and innovative activity

    NARCIS (Netherlands)

    Vossen, RW

    1999-01-01

    This paper discusses the paradox between the positive effect of industrial concentration on R & D spending, and its non-positive effect on the number of innovations. Also, I analyze whether concentration has different effects on small- and large-firm R & D. The analysis shows that the positive effec

  15. Concentration inequalities for random fields via coupling

    NARCIS (Netherlands)

    Chazottes, J. R.; Collet, P.; Kuelske, C.; Redig, F.

    2007-01-01

    We present a new and simple approach to concentration inequalities in the context of dependent random processes and random fields. Our method is based on coupling and does not use information inequalities. In case one has a uniform control on the coupling, one obtains exponential concentration inequ

  16. Fibrinogen Concentrate Therapy in Complex Cardiac Surgery

    NARCIS (Netherlands)

    Bilecen, Suleyman; Peelen, Linda M.; Kalkman, Cor J.; Spanjersberg, Alexander J.; Moons, Karel G. M.; Nierich, Arno P.

    2013-01-01

    Objectives: Fibrinogen concentrate increasingly is used to treat coagulopathic bleeding in cardiac surgery although its effectiveness and safety have not been shown. The authors conducted a cohort study to quantify the effects of fibrinogen concentrate on postoperative blood loss and transfusion and

  17. Stress Concentration around Holes in Anistropic Sheets

    DEFF Research Database (Denmark)

    Krenk, Steen

    1979-01-01

    The formulation of stress concentration problems of plane anisotropic elasticity in terms of integral equations is discussed. First the singular solutions of a concentrated force and a dislocation are formulated so that they remain valid in the case of double roots. The distribution of singularit...

  18. Maximum phytoplankton concentrations in the sea

    DEFF Research Database (Denmark)

    Jackson, G.A.; Kiørboe, Thomas

    2008-01-01

    A simplification of plankton dynamics using coagulation theory provides predictions of the maximum algal concentration sustainable in aquatic systems. These predictions have previously been tested successfully against results from iron fertilization experiments. We extend the test to data collect...... predictions. The results imply that physical processes control maximum particle concentrations in planktonic systems....

  19. Obtain of uranium concentrates from fertil liquids

    International Nuclear Information System (INIS)

    This research tried to encounter the form to remove uranium from the rock in the best way, for that it was used different process like leaching, extraction, concentration and precipitation. To leach the mineral was chosen basic leaching, using a mixture of carbonate-sodium bicarbonate, this method is more adequated for the basic nature of the mineral. In extraction was used specific uranium ionic interchanges, so was chosen a tertiary amine like Alamina 336. The concentration phase is intimately binding with the extraction by ionic interchange, for the capability of resine's extraction to obtain concentrated liquids. When the liquids were obtained with high concentration of uranium in the same time were purified and then were precipitated, for that we employed a precipitant agent like: Sodium hydroxide, Amonium hydroxide, Magnesium hydroxide, Hydrogen peroxide and phosphates. With all concentrates we obtain the YELLOW CAKE

  20. Postmortem Femoral Blood Concentrations of Risperidone

    DEFF Research Database (Denmark)

    Linnet, Kristian; Johansen, Sys Stybe

    2014-01-01

    Postmortem femoral blood concentrations of the antipsychotic drug risperidone and the active metabolite 9-hydroxyrisperidone were determined by an achiral LC-MS/MS method in 38 cases. The cause of death was classified as unrelated to risperidone in 30 cases, in which the sum of the concentration of...... the drug and metabolite ranged from below the limit of quantification to 0.058 mg/kg (median 0.0098 mg/kg). This concentration range, which largely corresponds to published in vivo plasmalevels under therapy, may serve as a reference for judgment of postmortem cases involving risperidone. In one case......, risperidone was judged to be a contributing factor to death, and the sum of concentrations was 0.29 mg/kg. This concentration is of the same order of magnitude as observed for plasma levels in clinical intoxication cases. For the remaining seven cases, the cause of death was unclear. The measurements observed...

  1. Plasma fibronectin concentrations in morbidly obese patients

    DEFF Research Database (Denmark)

    Dejgaard, A; Andersen, T; Christoffersen, Pernille Yde;

    1984-01-01

    Plasma fibronectin concentrations and liver morphology were investigated in 45 morbidly obese subjects (median overweight 88%) and in 42 normal weight controls, matched for sex and age. A significantly (P less than 0.01) raised plasma fibronectin concentration (median 464 mg/l, range 276-862 mg....../l) was found in the obese subjects when compared with concentrations in the controls (median 348 mg/l, range 164-536 mg/l). Plasma fibronectin concentrations of the obese patients correlated significantly to their degree of overweight (r = 0.33, P less than 0.05) as well as to the degree of fatty change...... found in their liver biopsies (r = 0.33, P less than 0.05). Significantly (P less than 0.05) elevated plasma fibronectin concentrations even in obese subjects without hepatic fatty change indicate that liver fat accumulation is no prerequisite of the obesity-related elevation of plasma fibronectin...

  2. Concentrated sunlight for organic solar cells

    DEFF Research Database (Denmark)

    Tromholt, Thomas

    2010-01-01

    Concentrated sunlight provides a novel approach to the study of the physical and electrical parameters of organic solar cells. The study of performance of organic solar cells at high solar concentrations provides insight into the physics, which cannot be studied with conventional solar simulators....... A high solar intensity study of inverted P3HT:PCBM solar cells is presented. Performance peak positions were found to be in the range of 1-5 suns, with smaller cells peaking at higher solar concentrations. Additionally, concentrated sunlight is demonstrated as a practical tool for accelerated...... polymers were degraded resulting in acceleration factors in the range of 19-55. This shows that concentrated sunlight can be used as qualitatively to determine the lifetime of polymers under highly accelerated conditions....

  3. Adaptive lens using liquid crystal concentration redistribution

    Science.gov (United States)

    Ren, Hongwen; Lin, Yi-Hsin; Wu, Shin-Tson

    2006-05-01

    An adaptive lens using electrically induced liquid crystal (LC)/monomer concentration redistribution is demonstrated. In the absence of an electric field, the LC/monomer mixture is homogeneously distributed. Application of an inhomogeneous electric field causes the LC molecules to diffuse towards the high field region and the liquid monomer towards the low field region. On the other hand, the LC molecules tend to diffuse from high to low concentration direction in order to balance the concentration change. A gradient LC concentration is thus obtained. Using the gradient LC concentration, we demonstrate a tunable-focus lens. Compared with a conventional LC lens, our lens has advantages in small astigmatism and without light scattering, but its response time is slower.

  4. Atmospheric relative concentrations in building wakes

    Energy Technology Data Exchange (ETDEWEB)

    Ramsdell, J.V. Jr.; Simonen, C.A.; Smyth, S.B. [Pacific Northwest Lab., Richland, WA (United States)

    1995-05-01

    This report documents the ARCON95 computer code developed for the U.S. Nuclear Regulatory Commission Office of Nuclear Regulatory Research for use in control room habitability assessments. The document includes a user`s guide to the code, a description of the technical basis for the code, and a programmer`s guide to the code. The ARCON95 code uses hourly meteorological data and recently developed methods for estimating dispersion in the vicinity of buildings to calculate relative concentrations at control room air intakes that would be exceeded no more five percent of the time. These concentrations are calculated for averaging periods ranging from one hour to 30 days in duration. Relative concentrations calculated by ARCON95 are significantly lower than concentrations calculated using the currently accepted procedure when winds are less than two meters per second. For higher wind speeds, ARCON95 calculates about the same concentrations as the current procedure.

  5. Atmospheric relative concentrations in building wakes

    International Nuclear Information System (INIS)

    This report documents the ARCON95 computer code developed for the U.S. Nuclear Regulatory Commission Office of Nuclear Regulatory Research for use in control room habitability assessments. The document includes a user's guide to the code, a description of the technical basis for the code, and a programmer's guide to the code. The ARCON95 code uses hourly meteorological data and recently developed methods for estimating dispersion in the vicinity of buildings to calculate relative concentrations at control room air intakes that would be exceeded no more five percent of the time. These concentrations are calculated for averaging periods ranging from one hour to 30 days in duration. Relative concentrations calculated by ARCON95 are significantly lower than concentrations calculated using the currently accepted procedure when winds are less than two meters per second. For higher wind speeds, ARCON95 calculates about the same concentrations as the current procedure

  6. Revealing source signatures in ambient BTEX concentrations

    International Nuclear Information System (INIS)

    Management of ambient concentrations of Volatile Organic Compounds (VOCs) is essential for maintaining low ozone levels in urban areas where its formation is under a VOC-limited regime. The significant decrease in traffic-induced VOC emissions in many developed countries resulted in relatively comparable shares of traffic and non-traffic VOC emissions in urban airsheds. A key step for urban air quality management is allocating ambient VOC concentrations to their pertinent sources. This study presents an approach that can aid in identifying sources that contribute to observed BTEX concentrations in areas characterized by low BTEX concentrations, where traditional source apportionment techniques are not useful. Analysis of seasonal and diurnal variations of ambient BTEX concentrations from two monitoring stations located in distinct areas reveal the possibility to identify source categories. Specifically, the varying oxidation rates of airborne BTEX compounds are used to allocate contributions of traffic emissions and evaporative sources to observed BTEX concentrations. - BTEX sources are identified from temporal variations of ambient concentration

  7. Soil dioxin concentrations in Baden-Wuerttemberg

    International Nuclear Information System (INIS)

    Soil dioxin levels in Baden-Wuerttemberg are generally low. Where high dioxin concentrations have been reported like in Rastatt, Rheinfelden, Crailsheim-Maulach and Eppingen these phenomena are local. Already at less than 100 metres distance, drastically lower concentrations are measured. At 1500 to 2000 metres distance the values are back to the ordinary background level. A programme for detecting sources of emission in the entire state revealed no further sites of heavy contamination. For this assessment of soil dioxin concentrations in Baden-Wuerttemberg 1275 soil samples were used, which is a vast amount also in comparison with nation-wide surveys. The average dioxin content in farmland is about 1 ng I-TEq/kg mT. Soil dioxin concentrations are the higher the greater the density of settlements and industry. In cities they are about three to five times higher than the ubiquitous background concentration. The highest concentrations measured were 5-20 ng I-TE/kg in garden soils in cities. Sewage sludge may be a significant source of dioxin contamination for farmland, far beyond the ubiquitous background concentration. Automobile exhaust gas caused higher soil contamination within 10 m along both sides of the roads as a function of traffic. Because scavengers in gasoline are now prohibited and catalysts are becoming more and more common the rate of additional dioxin and furan contamination due to traffic will decrease. Currently, traffic-related emissions in Baden-Wuerttemberg are well below 2 g I-TEq. (orig./EF)

  8. Concentrations of estrogens in patients with preeclampsia.

    Science.gov (United States)

    Zeisler, Harald; Jirecek, Stefan; Hohlagschwandtner, Maria; Knöfler, Martin; Tempfer, Clemens; Livingston, Jeffrey C

    2002-06-28

    The role of estrogens in the pathophysiology of preeclampsia remains to be determined. The aim of our study was to compare serum concentrations of 17 beta-estradiol and estriol in women with preeclampsia to normotensive pregnant controls. Serum concentrations of estrogens were measured in women with mild (n = 24) and severe (n = 24) preeclampsia as well as is normotensive pregnant controls (n = 24). Patients were matched for gestational age. Pregnancies complicated by early onset severe preeclampsia are associated with increased rates of maternal and fetal morbidity. Subsequently, we created further subgroups before and after 34 weeks of gestation (34 + 0). Serum estrogen concentrations were determined by standard ELISA technique. Compared to normotensive controls, the differences between the overall median serum concentrations of 17 beta-estradiol in women with mild (3811 v. 3730 pg/ml, P = 0.9) and severe (3811 v. 3630 pg/ml, P = 0.1) preeclampsia were statistically not significant. The differences between the overall median serum concentrations of estroil in controls and in patients with mild (121 v. 76 ng/ml, P = 0.6) and severe (121 v. 79 ng/ml, P = 0.4) preeclampsia were similar. The differences between the median concentrations of 17 beta-estradiol in patient with early onset severe preeclampsia compared to patients with mild preeclampsia (3061 v. 3715 pg/ml, P = 0.004) and controls (3061 v. 3807 pg/ml, P = 0.006) were statistically significant. In addition, the differences between the median concentrations of estriol in women with early onset severe preeclampsia compared to controls were statistically significant (20 v. 92 ng/ml, P = 0.02). The differences between the median concentrations of estrogens in those with late onset severe preeclampsia compared to women with mild preeclampsia were not significant. We found significantly lower concentrations of estrogens in women with early onset severe preeclampsia. PMID:12422581

  9. Computational algorithm for molybdenite concentrate annealing

    International Nuclear Information System (INIS)

    Computational algorithm is presented for annealing of molybdenite concentrate with granulated return dust and that of granulated molybdenite concentrate. The algorithm differs from the known analogies for sulphide raw material annealing by including the calculation of return dust mass in stationary annealing; the latter quantity varies form the return dust mass value obtained in the first iteration step. Masses of solid products are determined by distribution of concentrate annealing products, including return dust and benthonite. The algorithm is applied to computations for annealing of other sulphide materials. 3 refs

  10. Footprints on Ammonia Concentrations from Environmental Regulations

    DEFF Research Database (Denmark)

    Skjøth, Carsten Ambelas; Ellermann, Thomas; Hertel, Ole;

    2008-01-01

    ceilings but also to reduce the atmospheric nitrogen disposition to local ecosystems. Such measures to reduce the load of nitrogen to local ecosystems were introduced in Denmark in 1994. In this paper we demonstrate that this regulation is reflected in the NH3 concentrations in Denmark. The danish...... legislation forces farmers to manure to the fields during the cropgrowing seasons. We have analysed the seasonal variation in local NH3 concentrations over the time period of 1989-2003. During this period the seasonal variation has changed from having moderate spring and autum concentration peaks to having a...

  11. Theoretical modelling of solar dish concentrator

    International Nuclear Information System (INIS)

    Full text: Concentrating solar power (CSP) technologies could be one of the major contributor to worlds future energy needs and which would be cheap and clean sources of energy. This would improve energy utilization, higher conversion efficiency with reliable and affordable supply of electricity to the public. The proposed approach is using different size and depth of solar dish concentrators to improve solar fraction using the aluminium foil as reflector. In this paper, different measurement of solar concentrators is investigated and aims to aims to introducing an improved methodology for solar fraction on incoming solar energy in wet climate. (author)

  12. CSF and plasma vasopressin concentrations in dementia.

    OpenAIRE

    Sørensen, P S; Hammer, M.; Vorstrup, S; Gjerris, F.

    1983-01-01

    In 16 patients with primary degenerative dementia mean CSF vasopressin concentration was lower (0.9 +/- 0.1 pg/ml (mean +/- SEM)) than in 28 control patients (1.3 +/- 0.1 (mean +/- SEM)) (p less than 0.01). In 18 patients with normal pressure hydrocephalus and potentially reversible dementia mean CSF vasopressin concentration (1.2 pg/ml +/- 0.1 (mean +/- SEM)) was not different from that found in controls. Several of the demented patients had inappropriate plasma vasopressin concentrations su...

  13. Maximum permissible concentrations and negligible concentrations for antifouling substances. Irgarol 1051, dichlofluanid, ziram, chlorothalonil and TCMTB

    NARCIS (Netherlands)

    Wezel AP van; Vlaardingen P van; CSR

    2001-01-01

    This report presents maximum permissible concentrations and negligible concentrations that have been derived for various antifouling substances used as substitutes for TBT. Included here are Irgarol 1051, dichlofluanide, ziram, chlorothalonil and TCMTB.

  14. Effect of carbon dioxide concentration on the bioleaching of a pyrite-arsenopyrite ore concentrate

    Energy Technology Data Exchange (ETDEWEB)

    Nagpal, S.; Dahlstrom, D. (Univ. of Utah, Salt Lake City (United States)); Oolman, T. (Radian Corp., Austin, TX (United States))

    1993-02-20

    The effect of carbon dioxide concentration on the bacterial leaching of a pyrite-arsenopyrite ore concentrate was studied in continuous-flow reactors. Steady-state operation with two feed slurry densities, 6 wt% and 16wt% solids, were tested for the effect of carbon dioxide concentration. Bacterial growth rates were estimated via the measurement of carbon dioxide consumption rates. Aqueous-phase carbon dioxide concentrations in excess of 10 mg/L were found to be inhibitory to bacterial growth.

  15. Seasonal Composite Chlorophyll Concentrations - Gulf of Maine

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This personal geodatabase contains raster images of chlorophyll concentrations in the Gulf of Maine. These raster images are seasonal composites, and were...

  16. Uranium recovery from phosphate rocks concentrated

    International Nuclear Information System (INIS)

    The reserves, geological data, chemical data and technical flowsheet from COPEBRAS and Goiasfertil ores are described, including the process of mining ore concentration. Samples of Goiasfertil ores are analysed by gravimetric analysis, for phosphate, and spectrofluorimetry for uranium. (author)

  17. Arctic and Southern Ocean Sea Ice Concentrations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly sea ice concentration for Arctic (1901 to 1995) and Southern oceans (1973 to 1990) were digitized on a standard 1-degree grid (cylindrical projection) to...

  18. Building integrated concentrating photovoltaics: A review

    International Nuclear Information System (INIS)

    For building integration, Concentrating Photovoltaic (CPV) systems can offer a host of advantages over conventional flat panel devices, the most notable being: a higher electrical conversion efficiency in the PV cells, better use of space, ease of recycling of constituent materials, and reduced use of toxic products involved in the PV cells' production process. However, the viability of Building-Integrated Concentrating PV (BICPV) systems is dependent on their ability to offer a comparative economic advantage over flat panel photovoltaic technologies whose market prices are decreasing from day to day and which offer other advantages such as ease of replacement of structural elements. A comparative analysis is presented of the main existing CPV systems' suitability for use in buildings, in which the different challenges specific to integration of each system are discussed. The systems are categorized by type of concentration technology and concentration factor. (author)

  19. Indoor radon concentrations in Vushtrri, Kosovo

    International Nuclear Information System (INIS)

    Indoor air radon concentration was measured by exposing trac ketch detectors in the two elementary schools, one high school, a kindergarten and the hospital in the city of Vushtrri. Measurements were performed with the radon monitor PRM-145, which uses alpha scintillation cells and serves to determine the current concentration of radon. The results we obtained are in the range between the average values of radon for the interior spaces, and values that pose a potential risk for lung cancer. Measuring the concentration of radon was done in total of 34 rooms and came up with values which are between 28Bqm-3 and 398Bqm-3. In order to reduce the concentration of radon, we have built a ventilation pump, then we performed repeated measurements and finally came with results between 130-145Bqm-3.

  20. Concentration of stable elements in food products

    Energy Technology Data Exchange (ETDEWEB)

    Montford, M.A.; Shank, K.E.; Hendricks, C.; Oakes, T.W.

    1980-01-01

    Food samples were taken from commercial markets and analyzed for stable element content. The concentrations of most stable elements (Ag, Al, As, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Cu, Fe, Hf, I, K, La, Mg, Mn, Mo, Na, Rb, Sb, Sc, Se, Sr, Ta, Th, Ti, V, Zn, Zr) were determined using multiple-element neutron activation analysis, while the concentrations of other elements (Cd, Hg, Ni, Pb) were determined using atomic absorption. The relevance of the concentrations found are noted in relation to other literature values. An earlier study was extended to include the determination of the concentration of stable elements in home-grown products in the vicinity of the Oak Ridge National Laboratory. Comparisons between the commercial and local food-stuff values are discussed.

  1. Ownership Concentration, Top Management and Board Compensation

    Directory of Open Access Journals (Sweden)

    Marcos Barbosa Pinto

    2013-05-01

    Full Text Available The degree of ownership concentration may influence executive and board compensation (Bebchuk & Fried, 2003. This article analyzes this relationship. Detailed information about top management and board compensation became available starting in 2010 through new Securities Commission filings. Linear regression models applied to a sample of 315 Brazilian companies traded on the national exchange indicate a negative and statistically significant economic correlation between executive compensation and the degree of ownership concentration. Ceteris paribus, companies with a lower degree of ownership concentration pay higher compensation to top executives. Family controlled companies pay more to their chief executive, but not to the managerial team as a whole, and the compensation of directors increases with a greater proportion of control group members or their relatives on the board. There was support for the Managerial Power Hypothesis in companies with a lower degree of ownership concentration and for the extraction of private benefits in companies where it is greater.

  2. 75 FR 23764 - Correspondent Concentration Risks

    Science.gov (United States)

    2010-05-04

    ... management committee. Managing Correspondent Concentrations Institutions should establish prudent internal... prudent risk management practices. Institutions also should be aware of their affiliates' exposures to... prudent ] risk management policies and procedures.\\2\\ Credit (asset) risk is the potential that...

  3. Concentration variation of radon in the room

    International Nuclear Information System (INIS)

    The study was carried out to determine the variation of radon concentration in the room. Radon detector used was solid nuclear tracks detector (SSNTD) LR-115. From this result, suitable points to make radon measurement was determined

  4. Concentration phenomena in the semilinear parabolic equation

    Institute of Scientific and Technical Information of China (English)

    谭忠

    2001-01-01

    We prove the existence of the global, but unbounded solution of the semilinear heat equations with critical Sobolev exponent, and that under some assumptions, the global unbounded classical solution concentrates on origin as t→∞.

  5. Radon concentration measurements in bituminous coal mines

    International Nuclear Information System (INIS)

    Radon measurements were carried out in Kozlu, Karadon and Uezuelmez underground coal mines of Zonguldak bituminous coal basin in Turkey. Passive-time integrating method, which is the most widely used technique for the measurement of radon concentration in air, was applied by using nuclear etched track detectors (CR-39) in the study area. The radon concentration measurements were performed on a total of 42 points in those three mines. The annual exposure, the annual effective dose and lifetime fatality risk, which are the important parameters for the health of workers, were estimated based on chronic occupational exposure to the radon gas, which is calculated using UNCEAR-2000 and ICRP-65 models. The radon concentrations at several coal production faces are higher than the action level of 1000 Bq m-3. It is suggested that the ventilation rates should be rearranged to reduce the radon concentration. (authors)

  6. High plasma urea concentrations in collodion babies

    OpenAIRE

    1987-01-01

    We describe two infants born with a collodion membrane; both were treated with a product containing 10% urea and 5% lactic acid and as a consequence were found to have a raised plasma urea concentration.

  7. Modular Distributed Concentrator for Solar Furnace Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This research proposes to develop a lightweight approach to achieving the high concentrations of solar energy needed for a solar furnace achieving temperatures of...

  8. Advancing Concentrating Solar Power Research (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2014-02-01

    Researchers at the National Renewable Energy Laboratory (NREL) provide scientific, engineering, and analytical expertise to help advance innovation in concentrating solar power (CSP). This fact sheet summarizes how NREL is advancing CSP research.

  9. Concentration of stable elements in food products

    International Nuclear Information System (INIS)

    Food samples were taken from commercial markets and analyzed for stable element content. The concentrations of most stable elements (Ag, Al, As, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Cu, Fe, Hf, I, K, La, Mg, Mn, Mo, Na, Rb, Sb, Sc, Se, Sr, Ta, Th, Ti, V, Zn, Zr) were determined using multiple-element neutron activation analysis, while the concentrations of other elements (Cd, Hg, Ni, Pb) were determined using atomic absorption. The relevance of the concentrations found are noted in relation to other literature values. An earlier study was extended to include the determination of the concentration of stable elements in home-grown products in the vicinity of the Oak Ridge National Laboratory. Comparisons between the commercial and local food-stuff values are discussed

  10. Large-scale Fresnel lens solar concentrator

    Science.gov (United States)

    Allums, S. L.; Hastings, L. J.; Jensen, W. S.

    1977-01-01

    Sun tracking solar collector using lightweight inexpensive acrylic lenses to concentrate sun's energy yields efficiency range of 50 percent at average fluid temperature of 125 C to 26 percent at 300 C.

  11. Roasting of refractory gold and silver concentrate

    International Nuclear Information System (INIS)

    In processing of precious metal ores with high pyrite content, refractory concentrates are obtained, which are difficult to process. A refractory gold and silver concentrate was leached with sodium cyanide. Results show low extraction percentages, being 34 % of gold and 40 % of silver. A roasting method to oxidize the concentrate was used, making it more susceptible to cyanidation, hence a more efficient way to extract precious metals. The variables include roasting temperature and roasting and cyanidation time. In addition, the hot calcine was added to the leaching solution at room temperature to analyze the effect on particle size and recovery. The best results, although not entirely satisfactory (50 % of gold and 61 % of silver) were obtained by roasting the concentrate for 4 h at 600 degree centigrade, followed by cyanidation for 20 h. The lime consumption to raise the pH to about 11.3 was increased markedly to 25 kg/m3. (Author) 11 refs.

  12. Know Concentration Before Giving Acetaminophen to Infants

    Science.gov (United States)

    ... For Consumers Consumer Updates Know Concentration Before Giving Acetaminophen to Infants Share Tweet Linkedin Pin it More ... Consumer Updates RSS Feed Download PDF (221 K) Acetaminophen Safety (Podcast) On this page Overdosing Has Been ...

  13. Concentration inequalities and martingale inequalities: a survey

    OpenAIRE

    Chung, Fan; Lu, Linyuan

    2006-01-01

    We examine a number of generalized and extended versions of concentration inequalities and martingale inequalities. These inequalities are effective for analyzing processes with quite general conditions as illustrated in an example for an infinite Polya process and web graphs.

  14. Seasonal Variation in Human Salivary Cortisol Concentration

    DEFF Research Database (Denmark)

    Persson, Roger; Garde, Anne Helene; Hansen, Åse Marie;

    2008-01-01

    -of-day (4 levels) as categorical predictors. Cortisol concentrations were analyzed on a log scale. The diurnal pattern of cortisol was similar across months (interaction between month and time of day: p>0.4). The main effects of month and time-of-day were statistically significant (p......Measurement of cortisol concentration can contribute important information about an individual's ability to adjust to various environmental demands of both physical and psychosocial origin. However, one uncertainty that affects the possibilities of correctly interpreting and designing field studies...... is the lack of observations of the impact of seasonal changes on cortisol excretion. For this reason, the month-to-month changes in diurnal cortisol concentration, the awakening cortisol response (ACR), maximum morning concentration, and fall during the day were studied in a group of 24 healthy men and women...

  15. A Continuous Process for RO Concentrate Desupersaturation

    OpenAIRE

    Lei, Jack

    2016-01-01

    Reverse osmosis (RO) desalination of inland brackish water can replenish dwindling water supplies in various regions around the world. However, successful implementation of RO technology requires high product water recovery (>85%) in order to minimize the volume of generated concentrate brine. Therefore, brine management is a critical aspect of inland water desalination. At high water recovery, dissolved mineral salts (e.g. CaSO4, CaCO3) may concentrate above their solubility limits and may c...

  16. Framework for Concentrated Strain Deployable Trusses

    OpenAIRE

    Mejia-Ariza, Juan Manuel

    2008-01-01

    This research presents a simplified framework for the analysis of deployable trusses using the concentrated strain approach and uses it to provide key insights into the many design decisions to be made in the development of concentrated strain architectures. The framework uses Euler Column Theory to derive closed form solutions to estimate truss performance. The results are compared to a classical solution and shown to give similar results. A range of strut and hinge hierarchy choices are con...

  17. A reliable method to concentrate circulating DNA.

    Science.gov (United States)

    Bryzgunova, Olga; Bondar, Anna; Morozkin, Evgeniy; Mileyko, Vladislav; Vlassov, Valentin; Laktionov, Pavel

    2011-01-15

    Concentration of circulating DNA probes is required to increase the amount of DNA involved in subsequent study (by polymerase chain reaction, sequencing, and microarray). This work was dedicated to the comparison of five different methods used for concentration of DNA circulating in blood. Precipitation of circulating DNA with acetone in the presence of triethylamine provides minimal DNA loss, high reproducibility, and at least three times higher DNA yield in comparison with the standard ethanol protocol. PMID:20828533

  18. Spectral Selectivity Applied To Hybrid Concentration Systems

    Science.gov (United States)

    Hamdy, M. A.; Luttmann, F.; Osborn, D. E.; Jacobson, M. R.; MacLeod, H. A.

    1985-12-01

    The efficiency of conversion of concentrated solar energy can be improved by separating the solar spectrum into portions matched to specific photoquantum processes and the balance used for photothermal conversion. The basic approaches of spectrally selective beam splitters are presented. A detailed simulation analysis using TRNSYS is developed for a spectrally selective hybrid photovoltaic/photothermal concentrating system. The analysis shows definite benefits to a spectrally selective approach.

  19. Cyclone concentrator for radioactive effluent processing

    International Nuclear Information System (INIS)

    The concentrator includes a processing tank feeded at the base by the effluent to concentrate with a constant level device, the tank is surrounded by vertical pipes heated by electricity and connected to the processing tank at the bottom and for the upper part at the top but tangentially. Over the tank is a condenser for the recovery of the vapor phase. It is specially designed for effluents containing gases and foams

  20. Effects of changes in steel industry concentration

    OpenAIRE

    Bobenič, T.; A. Bobenič Hintošová; Hliboká, L.; I. Vasková

    2015-01-01

    The paper on a basis of completed mergers and acquisitions within global steel industry presents changes in steel industry concentration and analyzes its effects on world trade with steel products and on prices of input materials as well as of output products. The analyses performed for the 1990 - 2012 period revealed that increased concentration in global steel industry did not lead to more intensive world trade with steel products; however it is connected with increase of finished products ...

  1. Racial Harassment, Ethnic Concentration and Economic Conditions

    OpenAIRE

    Dustmann, Christian; Fabbri, Francesca; Preston, Ian

    2004-01-01

    In this paper, we analyse the association between the spatial concentration of ethnic minorities and racial harassment. Ethnic concentration relates to racial harassment through at least three channels: hostility in the attitudes of majority individuals that finds expression in harassment behaviour, the probability that minority individuals meet majority individuals, and the cost of expressing hostility aggressively. Thus, harassment cannot simply be modelled as a stronger form of hostility. ...

  2. Concentric Polycyclic Regrowth Pattern in Alopecia Areata

    Science.gov (United States)

    Delorenze, Lilian Mathias; Gavazzoni-Dias, Maria Fernanada Reis; Teixeira, Marcelo S; Aide, Marcia Kalil

    2016-01-01

    Alopecia areata (AA) is a common form of autoimmune nonscarring hair loss of scalp and/or body. Atypical hair regrowth in AA is considered a rare phenomenon. It includes atypical pattern of hair growth (sudden graying, perinevoid alopecia, Renbok phenomenon, castling phenomenon, and concentric or targetoid regrowth) and atypical dark color hair regrowth. We report a case of AA that resulted in a concentric targetoid hair regrowth and discuss the possible related theories regarding the significance of this phenomenon.

  3. White butterflies as solar photovoltaic concentrators

    OpenAIRE

    Katie Shanks; Senthilarasu, S.; ffrench-Constant, Richard H.; Mallick, Tapas K.

    2015-01-01

    Man’s harvesting of photovoltaic energy requires the deployment of extensive arrays of solar panels. To improve both the gathering of thermal and photovoltaic energy from the sun we have examined the concept of biomimicry in white butterflies of the family Pieridae. We tested the hypothesis that the V-shaped posture of basking white butterflies mimics the V-trough concentrator which is designed to increase solar input to photovoltaic cells. These solar concentrators improve harvesting efficie...

  4. Mercury Concentration in Environmental Samples of Malaysia

    OpenAIRE

    Sakamoto, Hayao; ICHIKAWA, Toshihiro; TOMIYASU, Takashi; Sato, Masanori

    2004-01-01

    The concentration and distribution of mercury in environmental samples (sea water, rock, sea sand, sediment, soil, fish and etc.) taken from various coastal sea areas and its ambient area in Malaysia were investigated. Mercury in environmental samples was subjected to the reduction-vaporization using of tin (II) chloride and heating-vaporization method. The mercury vapor was concentrated with a porous gold collector. Afterwards, mercury vapor evolved from the heated collector was determined b...

  5. Serum immunoreactive trypsin concentrations in diabetic children.

    OpenAIRE

    Moffat, A.; Marks, V.; Gamble, D. R.

    1980-01-01

    Serum immunoreactive trypsin (SIT) concentrations measured in 616 children with diabetes of recent onset were low, in both boys and girls, in comparison with reference ranges established in patients with non-diabetic, non-infectious illnesses. The mean SIT concentration was 60% of the mean reference level in children tested within three weeks of the onset of diabetes, and about 40% in patients tested six months after the onset of diabetes. Very low SIT levels were found in about 10% of patien...

  6. Nonlinear optical measurements of glucose concentration

    Science.gov (United States)

    Yakovlev, V. V.

    2008-02-01

    Diabetes mellitus is a metabolic disease that currently affects about 7% of the US population, or roughly about 20 million people. Effectively controlling diabetes requires regular measurements of the blood sugar levels to ensure the one time insulin injection when the concentration of glucose reaches a critical level. In this report, nonlinear Raman microspectroscopy is demonstrated to be a promising new way of continuous and noninvasive way of measuring the glucose concentration.

  7. Concentration of actinides in the food chain

    International Nuclear Information System (INIS)

    Considerable concern is now being expressed over the discharge of actinides into the environment. This report presents a brief review of the chemistry of the actinides and examines the evidence for interaction of the actinides with some naturally-occurring chelating agents and other factors which might stimulate actinide concentration in the food chain of man. This report also reviews the evidence for concentration of actinides in plants and for uptake through the gastrointestinal tract. (author)

  8. Geogenic heavy metal concentrations in German soils

    International Nuclear Information System (INIS)

    In the area of the German Federal Republic, 6,300 soil samples of 526 soil profiles were examined for the concentrations of lead, copper, zinc, cadmium, nickel, cobalt, mercury, antimony, arsenic and lithium. The soil profiles were selected so that the prevailing loose and solid rock floors of the German Federal Republic were represented. The analysis data of these samples formed the basis for the calculation of average geogenic heavy metal concentrations in the soils of the German Federal Republic. (orig.)

  9. Characterization of Fresnel-Köhler Concentrator

    OpenAIRE

    Cvetkovic, Aleksandra; Mohedano del Pozo, Raúl; Zamora Herranz, Pablo; Benitez Gimenez, Pablo; Miñano Dominguez, Juan Carlos; Chaves, Julio; Hernández Sanz, Maikel; Vilaplana, J.

    2010-01-01

    Getting a lower energy cost has always been a challenge for concentrated photovoltaic. The FK concentrator enhances the performance (efficiency, acceptance angle and manufacturing tolerances) of the conventional CPV system based on a Fresnel primary stage and a secondary lens, while keeping its simplicity and potentially low-cost manufacturing. This work presents some measured performance features of a FK prototype that show its skills and potential for the achievement of competitive electric...

  10. Clinical value of serum immunoreactive trypsin concentration

    OpenAIRE

    Ruddell, W S J

    1982-01-01

    The clinical value of estimation of serum concentrations of immunoreactive trypsin was evaluated by studying 46 healthy controls, 23 controls in hospital, 44 patients with chronic pancreatic disease, and 184 patients with non-pancreatic conditions in which pancreatic disease commonly enters into the differential diagnosis. Serum trypsin concentration had a log normal distribution in the controls, and the calculated normal range was considerably wider than that previously reported. The concent...

  11. A statistical proxy for sulphuric acid concentration

    Directory of Open Access Journals (Sweden)

    S. Mikkonen

    2011-07-01

    Full Text Available Gaseous sulphuric acid is a key precursor for new particle formation in the atmosphere. Previous experimental studies have confirmed a strong correlation between the number concentrations of freshly formed particles and the ambient concentrations of sulphuric acid. This study evaluates a body of experimental gas phase sulphuric acid concentrations, as measured by Chemical Ionization Mass Spectrometry (CIMS during six intensive measurement campaigns and one long-term observational period. The campaign datasets were measured in Hyytiälä, Finland, in 2003 and 2007, in San Pietro Capofiume, Italy, in 2009, in Melpitz, Germany, in 2008, in Atlanta, Georgia, USA, in 2002, and in Niwot Ridge, Colorado, USA, in 2007. The long term data were obtained in Hohenpeissenberg, Germany, during 1998 to 2000. The measured time series were used to construct proximity measures ("proxies" for sulphuric acid concentration by using statistical analysis methods. The objective of this study is to find a proxy for sulfuric acid that is valid in as many different atmospheric environments as possible. Our most accurate and universal formulation of the sulphuric acid concentration proxy uses global solar radiation, SO2 concentration, condensation sink and relative humidity as predictor variables, yielding a correlation measure (R of 0.87 between observed concentration and the proxy predictions. Interestingly, the role of the condensation sink in the proxy was only minor, since similarly accurate proxies could be constructed with global solar radiation and SO2 concentration alone. This could be attributed to SO2 being an indicator for anthropogenic pollution, including particulate and gaseous emissions which represent sinks for the OH radical that, in turn, is needed for the formation of sulphuric acid.

  12. A statistical proxy for sulphuric acid concentration

    Directory of Open Access Journals (Sweden)

    S. Mikkonen

    2011-11-01

    Full Text Available Gaseous sulphuric acid is a key precursor for new particle formation in the atmosphere. Previous experimental studies have confirmed a strong correlation between the number concentrations of freshly formed particles and the ambient concentrations of sulphuric acid. This study evaluates a body of experimental gas phase sulphuric acid concentrations, as measured by Chemical Ionization Mass Spectrometry (CIMS during six intensive measurement campaigns and one long-term observational period. The campaign datasets were measured in Hyytiälä, Finland, in 2003 and 2007, in San Pietro Capofiume, Italy, in 2009, in Melpitz, Germany, in 2008, in Atlanta, Georgia, USA, in 2002, and in Niwot Ridge, Colorado, USA, in 2007. The long term data were obtained in Hohenpeissenberg, Germany, during 1998 to 2000. The measured time series were used to construct proximity measures ("proxies" for sulphuric acid concentration by using statistical analysis methods. The objective of this study is to find a proxy for sulfuric acid that is valid in as many different atmospheric environments as possible. Our most accurate and universal formulation of the sulphuric acid concentration proxy uses global solar radiation, SO2 concentration, condensation sink and relative humidity as predictor variables, yielding a correlation measure (R of 0.87 between observed concentration and the proxy predictions. Interestingly, the role of the condensation sink in the proxy was only minor, since similarly accurate proxies could be constructed with global solar radiation and SO2 concentration alone. This could be attributed to SO2 being an indicator for anthropogenic pollution, including particulate and gaseous emissions which represent sinks for the OH radical that, in turn, is needed for the formation of sulphuric acid.

  13. Biologic Concentration Testing in Inflammatory Bowel Disease

    OpenAIRE

    Vaughn, Byron P; Sandborn, William J; Cheifetz, Adam S.

    2015-01-01

    Abstract: Anti-TNF medications have revolutionized the care of patients with inflammatory bowel disease. However, despite an initial robust effect, loss of response is common and long-term results are disappointing. Much of this lack of durability may be due to inadequate dose optimization, and recent studies suggest a correlation between serum drug concentrations and clinical outcomes. Currently, in clinical practice, measurement of drug concentrations and antibodies to drug are typically pe...

  14. Spectral converters and luminescent solar concentrators

    Energy Technology Data Exchange (ETDEWEB)

    Scudo, Petra F.; Abbondanza, Luigi; Fusco, Roberto; Caccianotti, Luciano [Eni S.p.A, Research Center for Non-Conventional Energies - Istituto ENI Donegani, Via G.Fauser 4, 28100 Novara (Italy)

    2010-07-15

    In this paper we present a comprehensive theoretical description of molecular spectral converters in the specific context of luminescent solar concentrators (LSCs). The theoretical model is an extension to a three-level system interacting with a solar radiation bath of the standard quantum theory of atomic radiative processes. We derive the equilibrium equations of the conversion process and provide specific examples of application of this principle to the development of solar concentration devices. (author)

  15. Spectral converters and luminescent solar concentrators

    OpenAIRE

    Scudo, Petra F.; Abbondanza, Luigi; Fusco, Roberto

    2009-01-01

    In this paper we present a comprehensive theoretical description of molecular spectral converters in the specific context of Luminescent Solar Concentrators (LSCs). The theoretical model is an extension to a three-level system interacting with a solar radiation bath of the standard quantum theory of atomic radiative processes. We derive the equilibrium equations of the conversion process and provide specific examples of application of this principle to the development of solar concentration d...

  16. Spectral converters and luminescent solar concentrators

    CERN Document Server

    Scudo, Petra F; Fusco, Roberto

    2009-01-01

    In this paper we present a comprehensive theoretical description of molecular spectral converters in the specific context of Luminescent Solar Concentrators (LSCs). The theoretical model is an extension to a three-level system interacting with a solar radiation bath of the standard quantum theory of atomic radiative processes. We derive the equilibrium equations of the conversion process and provide specific examples of application of this principle to the development of solar concentration devices.

  17. An Introduction to Matrix Concentration Inequalities

    OpenAIRE

    Tropp, Joel A.

    2015-01-01

    Random matrices now play a role in many areas of theoretical, applied, and computational mathematics. Therefore, it is desirable to have tools for studying random matrices that are flexible, easy to use, and powerful. Over the last fifteen years, researchers have developed a remarkable family of results, called matrix concentration inequalities, that achieve all of these goals. This monograph offers an invitation to the field of matrix concentration inequalities. It begins with some histo...

  18. Filterability and Sludge Concentration in Membrane Bioreactors

    OpenAIRE

    Lousada-Ferreira, M

    2011-01-01

    The Thesis entitled “Filterability and Sludge Concentration in Membrane Bioreactors” aims at explaining the relation between Mixed Liquid Suspended Solids (MLSS) concentration, the amount of solids in the wastewater being treated, also designated as sludge, and filterability, being the ability of the sludge to be filtrated through a membrane, in a wastewater treatment system designated as Membrane Bioreactor (MBR). An MBR is a wastewater treatment system that combines an activated sludge proc...

  19. Serum Trace Element Concentrations in Rheumatoid Arthritis.

    Science.gov (United States)

    Sahebari, Maryam; Ayati, Razie; Mirzaei, Hamed; Sahebkar, Amirhossein; Hejazi, Sepideh; Saghafi, Massoud; Saadati, Nayyereh; Ferns, Gordon A; Ghayour-Mobarhan, Majid

    2016-06-01

    Rheumatoid arthritis (RA) is a condition that is associated with oxidative stress. Serum trace elements and their related transport proteins, e.g., albumin and ceruloplasmin, play an important role in the antioxidant defense. Trace element status may therefore be involved in the pathogenesis of RA or be affected by the disease activity of this chronic inflammatory condition. The study participants were 110 patients with RA and 100 sex- and age-matched healthy volunteers. Serum concentrations of albumin, ceruloplasmin, selenium, zinc, copper, and zinc/copper ratio were measured in all subjects. The relationship between these parameters and disease activity score was also assessed. Lower concentrations of serum Alb, Zn, and Se were independently related to disease activity index. High concentrations of serum copper were associated with the presence of RA. Serum Cu concentrations were positively related to disease activity as assessed by the disease activity score. Low serum concentrations of Zn and Se, and high serum Cu concentrations may be associated with the presence of RA or be a consequence of this condition. Of the trace elements that were investigated in the present study, only serum Cu was positively correlated with disease activity. PMID:26450515

  20. Concentration of trace elements in marine organisms

    International Nuclear Information System (INIS)

    Information on the quality and quantity of stable trace elements in marine environments is frequently required to analyze the radioecological behavior of radionuclides released from nuclear facilities into the sea. In the present work, special attention was concentrated in determination of stable Mn, Fe, Co, Zn, Rb and Cs in marine organisms to estimate the concentration factors for these elements and corresponding radionuclides. Marine organisms (fishes, marine invertebrates and seaweeds) were collected at the seashore of Ibaragi prefecture and provided for chemical analysis after dry-ashing and wet-ashing. Atomic absorption spectrophotometry and neutron activation analysis were applied to determine the concentration of elements. The concentration of stable elements in fish muscle was independent on species of the fishes though slightly higher trends were observed in ''Usumebaru'', Sebastes nivosus for Cs, ''Ishimochi'', Nibea mitsukurii for Zn and Fe compared with other species. The concentration of Co, Zn and Fe in muscle of marine invertebrates was one order of magnitude higher than fish muscles especially in shellfishes for Co. Seaweeds showed peculiar species specificity for the concentration of stable trace elements and remarkable differences was observed between the species even among the same genus. (auth.)

  1. Influence of aerosol concentration and multivariate processing on indication of radon progeny concentration in air

    International Nuclear Information System (INIS)

    Indication of concentration of radon progeny gauge in air is sensitive to aerosol concentration. Minimum detectable concentration and accuracy of the measurement is determined by random errors of the gauge. Multivariate data processing can be used to decrease random errors. To investigate influence of aerosol concentration on indication of radon progeny concentration in air, measurements of mining radiometer, operating on the principle of alpha radiation detection from radon progeny deposited on air filter, were carried out in radon chamber. Aerosol concentration and radon concentration in radon chamber were controlled and measurements of radon progeny concentration was measured by radon progeny monitor. Additionally count rate from the monitor detector originating from alpha activity deposited on air filter was measured in 1 min. intervals that were later used for three interval, and Principal Component Regression (PCR) data processing. It was found that for aerosol concentration in air from 40 p/cm3 to approx. 9 000 p/cm3 indications of the radon progeny monitor depends considerably on aerosol concentration. Radon daughters concentration normalized to radon concentration against aerosol concentration varied from 0.3-0.9. In mines where the aerosol concentration generally is high, this phenomenon has a little effect on the indication of the radon progeny monitor, but is has to be taken into account where aerosol concentration is low. Comparison of random errors when measured signal of the monitor (count rate against time) was processed employing three interval method and PCR data processing shows that PCR ensures 2-3 times lower random error than three interval data processing. (author)

  2. Study of the effect of total serum protein and albumin concentrations on canine fructosamine concentration.

    Science.gov (United States)

    Loste, A; Marca, M C

    1999-01-01

    The relationship among serum fructosamine concentration and total serum protein and albumin concentrations were evaluated in healthy and sick dogs (diabetics and dogs with insulinoma were not included). Fructosamine was determined using a commercial colorimetric nitroblue tetrazolium method applied to the Technicon RA-500 (Bayer). Serum fructosamine concentration was not correlated to total protein in normoproteinemic (r = 0.03) and hyperproteinemic dogs (r = 0.29), but there was a high correlation (r = 0.73) in hypoproteinemic dogs. Similar comparison between serum fructosamine and albumin concentrations showed middle correlation (r = 0.49) in normoalbuminemic dogs and high degree of correlation (r = 0.67) in hypoalbuminemic dogs. These results showed the importance of recognizing serum glucose concentration as well as total serum protein and albumin concentrations in the assay of canine serum fructosamine concentration. PMID:10369572

  3. The SMS3D photovoltaic concentrator

    Science.gov (United States)

    Cvetković, Aleksandra; Hernandez, Maikel; Benítez, Pablo; Miñano, Juan Carlos; Schwartz, Joel; Plesniak, Adam; Jones, Russ; Whelan, David

    2008-08-01

    A novel photovoltaic concentrator is presented. The goal is to achieve high concentration design with high efficiency and high acceptance angle that in the same time is compact and convenient for thermal and mechanical management [1]. This photovoltaic system is based on 1 cm2 multi-junction tandem solar cells and an XR concentrator. The XR concentrator in this system is an SMS 3D design formed by one reflective (X) and one refractive (R) free-form surfaces (i.e., without rotational or linear symmetry) and has been chosen for its excellent aspect ratio and for its ability to perform near the thermodynamic limit. It is a mirror-lens device that has no shadowing elements and has square entry aperture (the whole system aperture area is used for collecting light). This large acceptance angle relaxes the manufacturing tolerances of all the optical and mechanical components of the system included the concentrator itself and is one of the keys to get a cost competitive photovoltaic generator. For the geometrical concentration of 1000x the simulation results show the acceptance angle of +/-1.8 deg. The irradiance distribution on the cell is achieved with ultra-short homogenizing prism, whose size is optimised to keep the maximum values under the ones that the cell can accept. The application of the XR optics to high-concentration is being developed in a consortium leaded by The Boeing Company, which has been awarded a project by US DOE in the framework of the Solar America Initiative.

  4. Biologic concentration testing in inflammatory bowel disease.

    Science.gov (United States)

    Vaughn, Byron P; Sandborn, William J; Cheifetz, Adam S

    2015-06-01

    Anti-TNF medications have revolutionized the care of patients with inflammatory bowel disease. However, despite an initial robust effect, loss of response is common and long-term results are disappointing. Much of this lack of durability may be due to inadequate dose optimization, and recent studies suggest a correlation between serum drug concentrations and clinical outcomes. Currently, in clinical practice, measurement of drug concentrations and antibodies to drug are typically performed only when a patient presents with active inflammatory bowel disease symptoms or during a potential immune-mediated reaction to anti-TNF ("reactive" setting). However, proactive monitoring of anti-TNF concentrations with titration to a therapeutic window (i.e., therapeutic concentration monitoring) represents a new strategy with many potential clinical benefits including prevention of immunogenicity, less need for IFX rescue therapy, and greater durability of IFX treatment. This review will cover the salient features of anti-TNF pharmacokinetics and pharmacodynamics and provide a rational approach for the use of anti-TNF concentration testing in both the reactive and proactive settings. PMID:25590953

  5. The statistics of LCDM Halo Concentrations

    CERN Document Server

    Neto, Angelo F; Bett, Philip; Cole, Shaun; Navarro, Julio F; Frenk, Carlos S; White, Simon D M; Springel, Volker; Jenkins, Adrian

    2007-01-01

    We use the Millennium Simulation (MS) to study the statistics of LCDM halo concentrations at z = 0. Our results confirm that the average halo concentration declines monotonically with mass; a power-law fits well the concentration-mass relation for over 3 decades in mass, up to the most massive objects to form in a LCDM universe (~ 10^15 h^-1 Msol). This is in clear disagreement with the predictions of the model proposed by Bullock et al. for these rare objects, and agrees better with the original predictions of Navarro, Frenk, & White. The large volume surveyed, together with the unprecedented numerical resolution of the MS, allow us to estimate with confidence the distribution of concentrations and, consequently, the abundance of systems with unusual properties. About one in a hundred cluster haloes (M200 >~ 3x10^14 h^-1 Msol) have concentrations exceeding c200 = 7.5, a result that may be used to interpret the likelihood of unusually strong massive gravitational lenses, such as Abell 1689, in the LCDM co...

  6. Novel aplanatic designs for LED concentration

    Science.gov (United States)

    Ricketts, Melissa; Winston, Roland; Jiang, Lun

    2014-09-01

    Aplanats make great concentrators because of their near perfect imaging. Aplanatic conditions can be satisfied using two surface curves (generally mirrored surfaces) in two dimensions (see Figure 1) which are constructed by successive approximation to create a highly efficient concentrator for both concentration and illumination. For concentration purposes, having a two mirror system would be impossible because the front mirror would block incoming light (see figure 2) so the idea is to replace the front mirror with a "one-way" mirror. Light from a lower index can be transmitted, so if the aplanat surface is a higher index light is allowed to enter, and be trapped. In the Jellyfish design, TIR takes place except for light striking the surface within the range of critical angles. To combat that, a small area of reflective coating is applied to the central top part of the Jellyfish, where TIR fails (In the middle) to keep the light there from directly escaping (see figure 3). The design works in both forwards and reverse. Light entering can be focused to a collecter, or the collecter can be replaced with a light source to concentrate light out. In this case, LEDs are used for their highly efficienct properties.

  7. Atmospheric relative concentrations in building wakes

    International Nuclear Information System (INIS)

    This report documents the ARCON96 computer code developed for the U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation for potential use in control room habitability assessments. It includes a user's guide to the code, a description of the technical basis for the code, and a programmer's guide to the code. The ARCON96 code uses hourly meteorological data and recently developed methods for estimating dispersion in the vicinity of buildings to calculate relative concentrations at control room air intakes that would be exceeded no more than five percent of the time. The concentrations are calculated for averaging periods ranging from one hour to 30 days in duration. ARCON96 is a revised version of ARCON95, which was developed for the NRC Office of Nuclear Regulatory Research. Changes in the code permit users to simulate releases from area sources as well as point sources. The method of averaging concentrations for periods longer than 2 hours has also been changed. The change in averaging procedures increases relative concentrations for these averaging periods. In general, the increase in concentrations is less than a factor of two. The increase is greatest for relatively short averaging periods, for example 0 to 8 hours and diminishes as the duration of the averaging period increases

  8. Holographic lenses for building integrated concentrating photovoltaics

    International Nuclear Information System (INIS)

    Highlights: • A holographic solar concentrator has been designed, constructed and characterised. • The system configuration is suitable for building integration. • The holographic lens diffracts in the bandwidth to which the cell is more sensitive. • The system prevents the cell overheating. • The use of the holographic element increases the electrical efficiency of the system. - Abstract: A volume transmission phase holographic element was designed and constructed to perform as a building integrated photovoltaic concentrator. The holographic lens diffracts light in the spectral bandwidth to which the cell presents the highest sensitivity with a concentration factor of 3.6X. In this way, the cell is protected from overheating because the infrared for which the solar cell is not sensitive is not concentrated. In addition, based on the asymmetric angular selectivity of the volume hologram and based on the linear concentration, only single-axis tracking is needed. The use of the holographic element increases the efficiency of the PV cell by 3% and the fill factor by 8%

  9. Plasma Glutamine Concentrations in Liver Failure.

    Directory of Open Access Journals (Sweden)

    Gunnel Helling

    Full Text Available Higher than normal plasma glutamine concentration at admission to an intensive care unit is associated with an unfavorable outcome. Very high plasma glutamine levels are sometimes seen in both acute and chronic liver failure. We aimed to systematically explore the relation between different types of liver failure and plasma glutamine concentrations.Four different groups of patients were studies; chronic liver failure (n = 40, acute on chronic liver failure (n = 20, acute fulminant liver failure (n = 20, and post-hepatectomy liver failure (n = 20. Child-Pugh and Model for End-stage Liver Disease (MELD scores were assessed as indices of liver function. All groups except the chronic liver failure group were followed longitudinally during hospitalisation. Outcomes were recorded up to 48 months after study inclusion.All groups had individuals with very high plasma glutamine concentrations. In the total group of patients (n = 100, severity of liver failure correlated significantly with plasma glutamine concentration, but the correlation was not strong.Liver failure, regardless of severity and course of illness, may be associated with a high plasma glutamine concentration. Further studies are needed to understand whether high glutamine levels should be regarded as a biomarker or as a contributor to symptomatology in liver failure.

  10. Antifungal serum concentration monitoring: an update.

    Science.gov (United States)

    Goodwin, Megan L; Drew, Richard H

    2008-01-01

    Invasive fungal infections (IFIs) are occurring with increasing incidence and are associated with significant morbidity and mortality. Understanding the relationship between the pharmacokinetic and pharmacodynamic properties of antifungals is essential to optimize the potential for favourable clinical and microbiological outcomes while minimizing risks of treatment-related toxicity. Antifungal serum concentrations may aid in the determination of appropriate dosing in select circumstances. The polyene and echinocandin classes of antifungals lack sufficient data to justify serum concentration monitoring in routine clinical practice. In contrast, serum concentration monitoring of flucytosine may help to reduce the risk of treatment-related haematological toxicity. Determination of itraconazole serum concentrations is advised in situations where the drug is used for prolonged periods to treat serious IFIs (such as invasive aspergillosis or histoplasmosis) because of variability in absorption following oral administration (most notable for the capsule formulation). The use of serum concentration monitoring during therapy with the extended-spectrum triazoles (i.e. voriconazole and posaconazole) is still evolving, due primarily to inter-patient variability in drug exposure combined with sparse data regarding relationships with efficacy (posaconazole) and both safety and efficacy (voriconazole). PMID:17999982

  11. Seller Concentration in the Grain Milling Industry

    Directory of Open Access Journals (Sweden)

    Martin Charumbira

    2010-01-01

    Full Text Available Problem statement: The main purpose of the study was to explore the levels of concentration in Zimbabwe’s grain-milling industry during period 1985-2005. The study could not be extended to periods after 2005 because the situation in the country had become economically chaotic. Approach: The methodology adopted involved the calculation of the concentration indices such as the Herfindall-Hirschman index, Hannah and Kay index, the Entropy index and the Four-Firm Concentration ratio. Results: The study revealed that liberalisation of the industry reduced seller concentration levels. The response to deregulation in this particular sector confirms the theoretical expectation that liberalisation promotes competition and reduces market power of existing firms, which is also consistent with the world-wide trends. Conclusion: The policies adopted at the inception of Economic Structural Adjustment Programmed (ESAP should be pursued more vigorously to create a manufacturing base which is open to competition and which is insulated from adverse effects of possible manipulation by a few large firms. Policy should be aimed at maintaining affordability of the basic commodities to the consumers as well as ensuring viability to the manufacturers. With high levels of industrial concentration, producers are able to operate at a higher-cost system without losing market share, but this is to the detriment of the consumers.

  12. Acoustic estimation of suspended sediment concentration

    Institute of Scientific and Technical Information of China (English)

    朱维庆; 朱敏; 周忠来; 潘锋; 霍其增; 张向军

    2001-01-01

    In this paper, the acoustic estimation of suspended sediment concentration is discussed and two estimation methods of suspended sediment concentration are presented. The first method is curve fitting method, in which, according to the acoustic backscattering theory we assume that the fit-ting factor K1 (r) between the concentration M(r) obtained by acoustic observation and the concentra-tion M0(r) obtained by sampling water is a high order power function of distance r. Using least-square algorithm, we can determine the coefficients of the high order power function by minimizing the differ-ence between M(r) and M0(r) in the whole water profile. To the absorption coefficient of sound due to the suspension in water we do not give constraint in the first method. The second method is recur-sive fitting method, in which we take M0(r) as the conditions of initialization and decision and give ra-tional constraints to some parameters. The recursive process is stable. We analyzed the two methods with a lot of experimental data. The analytical results show that the estimate error of the first method is less than that of the second method and the latter can not only estimate the concentration of suspended sediment but also give the absorption coefficient of sound. Good results have been obtained with the two methods.

  13. A Review of Solar Photovoltaic Concentrators

    Directory of Open Access Journals (Sweden)

    Mehrdad Khamooshi

    2014-01-01

    Full Text Available Throughout the recent centuries, the limits of using energy resources due to the cost and environmental issues became one of the scientists’ concerns. Because of the huge amount of energy received by the Earth from the sun, the application of photovoltaic solar cells has become popular in the world. The photovoltaic (PV efficiency can be increased by several factors; concentrating photovoltaic (CPV system is one of the important tools for efficiency improvement and enables for a reduction in the cell area requirement. The limits of the PV area can reduce the amount of absorbing irradiation; CPV systems can concentrate a large amount of sunlight into a smaller one by applying lenses or curved and flat mirrors. However, the additional costs on concentrating optics and cooling systems made CPV less common than nonconcentrated photovoltaic. This paper reviews the different types of PV concentrators, their performance with advantages and disadvantages, concentration ratio, acceptance angle, brief comparison between their efficiencies, and appropriate cooling system.

  14. Rapid determination of radon daughter concentrations

    International Nuclear Information System (INIS)

    A technical evaluation of four radon 222 progeny measuring instruments has been conducted. The evaluation has been carried out under laboratory controlled conditions and at several locations in an underground uranium mine. The laboratory evaluation consisted of a thorough study of the behaviour and performance of the instruments under a wide variety of environmental conditions such as radon 222 gas concentration, radon 222 progeny concentration, temperature, relative humidity, aerosol concentration, and gamma-field exposure. The four instruments tested were: the Pylon WL-1000C, the MDA IWLM-811, the MIMIL IIM, and the EDA WLM-30. The readings of the instruments were compared with a widely accepted radon 222 progeny concentration measuring method, namely, the Thomas-Tsivoglou method. Two variables affected two instruments significantly, namely, under high aerosol concentration conditions, one of the instruments (EDA WLM-30) ceased to operate because of filter loading. The other variable was gamma-field exposure which affected another instrument (MDA-811) adversely. The instruments were rated according to several criteria. The overall best performer was the MIMIL IIM, although other instruments also fared quite well under a variety of experimental conditions

  15. Investigation of distribution of indoor radon concentration

    International Nuclear Information System (INIS)

    This paper reports the measured results of radon concentrations at different positions of a house with CSR solid track detector with and without electret. The results show that the radon concentration is different positions of even the same room, it is the highest at end of a bed close to the wall, where his/her head usually is when the resident is on bed, being 1.6-1.8 times that at the position 0.5 m below the ceiling, and that at the middle of the room the radon concentration is decreasing with increasing height from the floor, the radon concentration at the height of 0.88 m is about 1.3 - 1.5 times that of 2.4 m (0.5 m below the ceiling). Based on the investigation, the radiation dose to the residents estimated in accordance with the average measured radon concentration at the location 0.5 m below the ceiling should be multiplied by a correction factor of about 1.5 to obtain the realistic dose. (Author)

  16. Contaminant concentrations in manatees in Florida

    Science.gov (United States)

    O'Shea, T.J.; Moore, J.F.; Kochman, H.I.

    1984-01-01

    The status of the endangered manatee (Trichehus manatus) in relation to organochlorine pesticides, polychlorinated biphenyls, mercury, lead, cadmium, copper, iron, and selenium was investigated in Florida from 1977 to 1981. Concentrations of organochlorines in blubber, mercury in muscle and liver, lead in liver, and lead and cadmium in kidneys did not indicate high exposure to these contaminants. Only cadmium in kidneys showed a positivde correlation with relative age. Copper concentrations in livers of these aquatic herbivores were significantly elevated in areas of high herbicidal copper usage after adjustment for significant age-related effects. Liver copper concentrations comparable to those associated with toxic effects in some domestic species were found in manatees from areas of high copper herbicide use. The use of copper herbicides for control of aquatic plants should be carefully managed in areas used intensively by manatees.

  17. Wide range radioactive gas concentration detector

    Science.gov (United States)

    Anderson, David F.

    1984-01-01

    A wide range radioactive gas concentration detector and monitor which is capable of measuring radioactive gas concentrations over a range of eight orders of magnitude. The device of the present invention is designed to have an ionization chamber which is sufficiently small to give a fast response time for measuring radioactive gases but sufficiently large to provide accurate readings at low concentration levels. Closely spaced parallel plate grids provide a uniform electric field in the active region to improve the accuracy of measurements and reduce ion migration time so as to virtually eliminate errors due to ion recombination. The parallel plate grids are fabricated with a minimal surface area to reduce the effects of contamination resulting from absorption of contaminating materials on the surface of the grids. Additionally, the ionization chamber wall is spaced a sufficient distance from the active region of the ionization chamber to minimize contamination effects.

  18. Material properties of concentrated pectin networks.

    Science.gov (United States)

    Zsivanovits, Gabor; MacDougall, Alistair J; Smith, Andrew C; Ring, Stephen G

    2004-05-17

    We have examined the mechanical behaviour of different types of pectin at high concentrations (> 30% w/w), relevant to the behaviour of pectin in the plant cell wall, and as a film-forming agent. Mechanical properties were examined as a function of counterion type (K(+), Ca(2+), Mg(2+)), concentration and extent of hydration. Hydration was controlled in an osmotic stress experiment where pectin films were exposed to concentrated polyethylene glycol [PEG] solutions of known osmotic pressure. We investigated the mechanical behaviour under simple extension. The results show that the swelling and stiffness of the films are strongly dependent on pectin source and ionic environment. At a fixed osmotic stress, both Ca(2+) or Mg(2+) counterions reduce swelling and increase the stiffness of the film. PMID:15113669

  19. Fibrinogen concentrate for bleeding - a systematic review

    DEFF Research Database (Denmark)

    Lunde, J; Stensballe, J; Wikkelsø, A;

    2014-01-01

    Fibrinogen concentrate as part of treatment protocols increasingly draws attention. Fibrinogen substitution in cases of hypofibrinogenaemia has the potential to reduce bleeding, transfusion requirement and subsequently reduce morbidity and mortality. A systematic search for randomised controlled...... trials (RCTs) and non-randomised studies investigating fibrinogen concentrate in bleeding patients was conducted up to November 2013. We included 30 studies of 3480 identified (7 RCTs and 23 non-randomised). Seven RCTs included a total of 268 patients (165 adults and 103 paediatric), and all were...... mortality were lacking. Weak evidence from RCTs supports the use of fibrinogen concentrate in bleeding patients, primarily in elective cardiac surgery, but a general use of fibrinogen across all settings is only supported by non-randomised studies with serious methodological shortcomings. It seems pre...

  20. Optimization of bolt thread stress concentrations

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

    Designs of threaded fasteners are controlled by different standards, and the number of different thread definitions is large. The most commonly used thread is probably the metric ISO thread, and this design is therefore used in the present paper. Thread root design controls the stress concentration...... factor of threads and therefore indirectly the bolt fatigue life. The root shape is circular, and from shape optimization for minimum stress concentration it is well known that the circular shape is seldom optimal. An axisymmetric Finite Element formulation is used to analyze the bolted connection, and a...... study is performed to establish the need for contact modeling with regard to finding the correct stress concentration factor. Optimization is performed with a simple parameterization with two design variables. Stress reduction of up to 9% is found in the optimization process, and some similarities are...

  1. Overflow Concentration and Sedimentation in Hoppers

    DEFF Research Database (Denmark)

    Hjelmager Jensen, Jacob; Saremi, Sina

    2014-01-01

    result of different timescales in the segregation of the various sediment fractions. The heavier constituents in a mixture will have had time to settle, and overflowing sediments are therefore primarily composed of the finer and lighter constituents, whose concentrations potentially exceed those at the...... inflow. The hopper constitutes a complex system despite its geometrical regularity; the complexities are largely from the settling processes in concentrated polydisperse mixtures. These settling processes can, however, be captured by employing available settling formulas applicable for multifractional...... mixtures, the former analytically. Although assumptions tied to the mathematical model are fulfilled best for hoppers rigged with a multiple-inflow system, the model accurately predicts measured concentrations in the final stage of overflow for single-inflow systems. The model can be used as a...

  2. Removal Of Volatile Impurities From Copper Concentrates

    Energy Technology Data Exchange (ETDEWEB)

    Winkel, L.; Schuler, A.; Frei, A.; Sturzenegger, M.

    2005-03-01

    To study the removal of volatile impurities from two different copper concentrates they have been heated on a thermo balance to temperatures between 900 and 1500 C. This sample treatment revealed that both concentrates undergo strong weight losses at 500 and 700 C. They were attributed to the removal of sulfur. Elemental analyses of the residues by ICP spectrometry have shown that the thermal treatment efficiently removes the volatile impurities. Already below 900 C most of the arsenic is removed by evaporation, the largest fraction of lead and zinc is removed in the temperature interval of 1300-1500 C. It was observed that quartz in the concentrate leads to the formation of a silicon-enriched phase besides a metal rich sulfide phase. The former is interpreted as an early stage of a silicate slag. Elemental analysis showed that the formation of this distinct slag phase does not hinder the efficient removal of volatile impurities. (author)

  3. Stretched Lens Array Photovoltaic Concentrator Technology Developed

    Science.gov (United States)

    Piszczor, Michael F., Jr.; O'Neill, Mark J.

    2004-01-01

    Solar arrays have been and continue to be the mainstay in providing power to nearly all commercial and government spacecraft. Light from the Sun is directly converted into electrical energy using solar cells. One way to reduce the cost of future space power systems is by minimizing the size and number of expensive solar cells by focusing the sunlight onto smaller cells using concentrator optics. The stretched lens array (SLA) is a unique concept that uses arched Fresnel lens concentrators to focus sunlight onto a line of high-efficiency solar cells located directly beneath. The SLA concept is based on the Solar Concentrator Array with Refractive Linear Element Technology (SCARLET) design that was used on NASA's New Millennium Deep Space 1 mission. The highly successful asteroid/comet rendezvous mission (1998 to 2001) demonstrated the performance and long-term durability of the SCARLET/SLA solar array design and set the foundation for further improvements to optimize its performance.

  4. Mechanisms of urine concentration and dilution (1961)

    International Nuclear Information System (INIS)

    This paper is devoted to the analysis of a problem in the field of renal physiology which has shown many new developments during the course of the last few years. The following are treated successively: a) the data obtained from measurements of free water clearance and their interpretation; b) the data provided by nephron morphology and the comparative anatomy of the kidney ; c) the data relative to the existence of an intrarenal osmotic gradient; d) the principle of concentration multiplication by a counter current technique; e) the present day theory of counter current concentration of urine, and f) the physiological check on dilution and concentration mechanisms in urine. Lastly, the advantages of the modern theory and the unknown factors which remain are discussed. (authors)

  5. Large scale water lens for solar concentration.

    Science.gov (United States)

    Mondol, A S; Vogel, B; Bastian, G

    2015-06-01

    Properties of large scale water lenses for solar concentration were investigated. These lenses were built from readily available materials, normal tap water and hyper-elastic linear low density polyethylene foil. Exposed to sunlight, the focal lengths and light intensities in the focal spot were measured and calculated. Their optical properties were modeled with a raytracing software based on the lens shape. We have achieved a good match of experimental and theoretical data by considering wavelength dependent concentration factor, absorption and focal length. The change in light concentration as a function of water volume was examined via the resulting load on the foil and the corresponding change of shape. The latter was extracted from images and modeled by a finite element simulation. PMID:26072893

  6. Device for controlling burnable gas concentration

    International Nuclear Information System (INIS)

    Purpose: To provide the subject device wherein the reaction flow quantity of gas in a recombiner is reduced for controlling hydrogen and oxygen to less than the burnable threshold value, and iodine is effectively removed. Constitution: The recombiner is started in operation, and gas within the dry well is introduced into a heater by means of a circulating device, and steam exhausted from the recombiner and gas are cooled by a cooler, thereafter they being returned to a suppression chamber. When the pressure within the suppression chamber is increased, a vacuum break valve is opened and the concentrations of hydrogen and oxygen are elevated. By the increase of the concentrations of hydrogen and oxygen the recombiner is reoperated and the concentrations are reduced. (Aizawa, K.)

  7. Concentration of tritium in the atmosphere

    International Nuclear Information System (INIS)

    Concentration of tritium in the atmosphere was measured in Ibaraki, Japan. At first, sampled air was passed through a column of molecular sieve, and all the water vapour was removed. Hydrogen gas obtained by the electrolysis of water was added to the air, and oxidized by a Pd catalyst column, then the oxidized hydrogen was absorbed by a last column of molecular sieves. These columns of molecular sieves were dehydrated by heating at 400 deg C. The concentration range of atmospheric HTO and HT was 1-2 pCi/m3 in Ibaraki for a year. The concentration of atmospheric HTO varied depending on the content of water vapour in air. (J.P.N.)

  8. CONCENTRATION OF WORLD EXPORTS OF FOREST PRODUCTS

    Directory of Open Access Journals (Sweden)

    Luiz Moreira Coelho Junior

    2013-12-01

    Full Text Available http://dx.doi.org/10.5902/1980509812353This study analyzed the degree of concentration in worldwide exports of forest products in the period rangingfrom 1961 to 2008. The data used are available at the United Nations Food and Agriculture Organization(FAO. The concentration was determined by the concentration ratio [HR (k], the Herfindahl-HirschmanIndex (HHI, Theil Entropy Index (E and the Gini index (G. The main conclusions were: The aggregateBrazilian share in the world exports of forest products is increasing over time; the most important sectors inthe aggregate world exports of forest products, in decreasing order, were pulp, lumber, paper and cardboard,wooden panels, saw and fire wood. According to Bain, the concentration ratio of the four and eight largestexporters of forest products is moderately low; the HHI and Theil Entropy (E show a reduction in theconcentration of world exports of forest products and greater competition among the countries that sell suchproducts; the Gini index indicates that despite the increase in export of forest products over the period ofanalysis, a smaller number of competitors concentrate increasingly larger shares of international exports of these products; summary indices (HHI, E and G indicated that increased competition has not led to a moreequitable distribution of forest products so as to bring down inequalities and concentration of profits in thesector; despite the downward trend in CR (4 and CR (8, there is an increase in G, probably because theeconomies of scale in the international trade have been held by few competitors; caution is recommendedin the analysis of summary indices (HHI, E and G which had better be checked jointly with the partialindices [CR (k] in order to avoid wrong conclusions; countries with a significant share in total exports, suchas Brazil, should seek business strategies to retain competitive advantages, especially those arising fromeconomies of scale.

  9. Beryllium concentration in pharyngeal tonsils in children

    Directory of Open Access Journals (Sweden)

    Ewa Nogaj

    2014-06-01

    Full Text Available Power plant dust is believed to be the main source of the increased presence of the element beryllium in the environment which has been detected in the atmospheric air, surface waters, groundwater, soil, food, and cigarette smoke. In humans, beryllium absorption occurs mainly via the respiratory system. The pharyngeal tonsils are located on the roof of the nasopharynx and are in direct contact with dust particles in inhaled air. As a result, the concentration levels of beryllium in the pharyngeal tonsils are likely to be a good indicator of concentration levels in the air. The presented study had two primary aims: to investigate the beryllium concentration in pharyngeal tonsils in children living in southern Poland, and the appropriate reference range for this element in children’s pharyngeal tonsils. Pharyngeal tonsils were extracted from a total of 379 children (age 2–17 years, mean 6.2 ± 2.7 years living in southern Poland. Tonsil samples were mineralized in a closed cycle in a pressure mineralizer PDS 6, using 65% spectrally pure nitric acid. Beryllium concentration was determined using the ICP-AES method with a Perkin Elmer Optima 5300DVTM. The software Statistica v. 9 was used for the statistical analysis. It was found that girls had a significantly greater beryllium concentration in their pharyngeal tonsils than boys. Beryllium concentration varies greatly, mostly according to the place of residence. Based on the study results, the reference value for beryllium in pharyngeal tonsils of children is recommended to be determined at 0.02–0.04 µg/g.

  10. Policy and Concentration of Activities: The Case of Dutch Nanotechnology

    NARCIS (Netherlands)

    Cunningham, S.; Werker, C.

    2012-01-01

    Geographical concentration of economic activities has been widely discussed. However, the insights into other kinds of concentration such as technological and organizational concentration have been scarce. Here, we analyze organizational, technological and geographical concentration of nanotechnolog

  11. Measuring probe for radon concentration monitoring

    International Nuclear Information System (INIS)

    Variation of radon emanation in mining excavation is caused by changes of stress in geologic layer, coal or other minerals are extracted from. To investigate this phenomenon, a model of an instrument for continuous monitoring of radon concentration in mine environment was developed. The measuring head constructed in the form of a cylinder operates with modified mining radiometer RGR-40. The instrument can measure radon concentration employing the method of natural diffusion of radon to the measuring head, or forced air sampling by an membrane air pump. The measuring results are stored in internal memory of the instrument and are displayed on LCD screen. (author)

  12. Concentration of sulfamethazine in spray dried milk

    OpenAIRE

    Malik, Shahana

    1991-01-01

    A study was conducted to investigate the effect ofspray drying on concentration of sulfamethazine (SMZ) in fluid milk dried to powder «10% moisture). Antibiotic-free skim and whole (homogenized) milk were spiked at 5, 10, 50 and 100 ppb sulfamethazine levels, pasteurized and stored at 4°C till further processed. All samples were spray dried at an inlet temperature of 180 ± 2°C and outlet temperature of 100 ± 2°C and stored at -20°C until analyzed. Sulfamethazine concentration was determ...

  13. Influence of surfactant concentration on nanohydroxyapatite growth

    Indian Academy of Sciences (India)

    D Gopi; J Indira; S Nithiya; L Kavitha; U Kamachi Mudali; K Kanimozhi

    2013-10-01

    Nanohydroxyapatite particles with different morphologies were synthesized through a microwave coupled hydrothermal method using CTAB as a template. A successful synthesis of nanosized HAP spheres, rods and fibres is achieved through this method by controlling the concentration of the surfactant. The concentration of the surfactant was tuned in such a way that the desired HAP nanostructures were obtained. The resultant powders were sintered at 900 °C in order to obtain phase pure HAP particles. The results obtained by Fourier transform infrared spectroscopy (FT–IR), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques have substantiated the formation of nanosized HAP spheres and fibres.

  14. Time-series analysis for ambient concentrations

    Science.gov (United States)

    González-Manteiga, W.; Prada-Sánchez, J. M.; Cao, R.; García-Jurado, I.; Febrero-Bande, M.; Lucas-Domínguez, T.

    In this paper we present a dynamic system which has been implemented to predict, every 5 min, the ambient concentrations of SO 2 in the neighbourhood of a power station run by ENDESA, the National Electricity Company of Spain, in As Pontes. This prediction task is very important in order to prevent a high ground-level of concentration of SO 2. For forecasting we use a mixed model which has a parametric component and a nonparametric one. We also construct confidence intervals for future observations using bootstrap and classical techniques.

  15. Cellulase Inhibition by High Concentrations of Monosaccharides

    DEFF Research Database (Denmark)

    Hsieh, Chia-Wen; Cannella, David; Jørgensen, Henning;

    2014-01-01

    Biological degradation of biomass on an industrial scale culminates in high concentrations of end products. It is known that the accumulation of glucose and cellobiose, end products of hydrolysis, inhibit cellulases and decrease glucose yields. Aside from these end products, however, other...... that low free water availability contributes to cellulase inhibition. Of the hydrolytic enzymes involved, those acting on the cellulose substrate, that is, exo- and endoglucanases, were the most inhibited. The β -glucosidases were shown to be less sensitive to high monosaccharide concentrations except...

  16. High efficiency compound semiconductor concentrator photovoltaics

    Science.gov (United States)

    Borden, P.; Gregory, P.; Saxena, R.; Owen, R.; Moore, O.

    1980-01-01

    Special emphasis was given to the high yield pilot production of packaged AlGaAs/GaAs concentrator solar cells, using organometallic VPE for materials growth, the demonstration of a concentrator module using 12 of these cells which achieved 16.4 percent conversion efficiency at 50 C coolant inlet temperature, and the demonstration of a spectral splitting converter module that achieved in excess of 20 percent efficiency. This converter employed ten silicon and ten AlGaAs cells with a dichroic filter functioning as the beam splitter. A monolithic array of AlGaAs/GaAs solar cells is described.

  17. A time-varying magnetic flux concentrator

    Science.gov (United States)

    Kibret, B.; Premaratne, M.; Lewis, P. M.; Thomson, R.; Fitzgerald, P. B.

    2016-08-01

    It is known that diverse technological applications require the use of focused magnetic fields. This has driven the quest for controlling the magnetic field. Recently, the principles in transformation optics and metamaterials have allowed the realization of practical static magnetic flux concentrators. Extending such progress, here, we propose a time-varying magnetic flux concentrator cylindrical shell that uses electric conductors and ferromagnetic materials to guide magnetic flux to its center. Its performance is discussed based on finite-element simulation results. Our proposed design has potential applications in magnetic sensors, medical devices, wireless power transfer, and near-field wireless communications.

  18. Radon concentrations in Taipei metropolitan railway station

    International Nuclear Information System (INIS)

    For routine airborne radon monitoring, including use in field conditions, the technique based on electret ion chamber technology seems to be the most suitable choice in many applications. However, this simple and relatively inexpensive method has some specific drawbacks: poorer reproducibility at lower radon concentrations, some uncertainty in the use of manufacturer suggested gamma correction factors, and limited reusability. A modified electret ion chamber method has been proposed, but it is mainly for water borne radon measurement. Therefore, we still applied the simple method recommended by the manufacturer to survey radon concentrations in Taipei Railway Station. (author)

  19. Measurement of HD concentration by gas chromatography

    International Nuclear Information System (INIS)

    Gas chromatography has been used for the on-line measurement of deuterium hydride (HD) which is used in a Tritium Removal Pilot Facility for the demonstration of the removal of the tritium mainly generated in CANDU reactors. Two methods with different carrier gases, neon and hydrogen, are tested and compared each other. It was showed that both the methods could be possible to measure the concentration of H2 and HD. However, the method with a column packed with alumina showed difficulty in the application due to quite long measurement time and reproducibility. The other method using hydrogen as a carrier gas could measure the concentration accurately within comparably short period

  20. Low holographic concentration effects on CIGS

    Science.gov (United States)

    Castillo, Jose E.; Russo, Juan M.; Zhang, Deming; Kostuk, Raymond K.; Rosenberg, Glenn A.

    2010-08-01

    We present the results of combining copper indium gallium (di)selenide (CIGS) photovoltaic cells with holographic planar concentrating film over a broad range of illumination levels. The film, originally designed for silicon bifacial solar applications worked well with the CIGS cells. The Voc, cell efficiency and fill factor reached full operating values at lower light levels; with a significant boost in performance being recorded. The holographic regions of the concentrator act as extended heat transfer surfaces, allowing the CIGS cells to operate at lower operational temperatures than they normally would in a traditional PV application.

  1. Design package for concentrating solar collector panels

    Energy Technology Data Exchange (ETDEWEB)

    1978-08-01

    Information used to evaluate the design of the Northrup concentrating collector is presented. Included are the system performance specifications, the applications manual, and the detailed design drawings of the collector. The Northrup concentrating solar collector is a water/glycol/working fluid type, dipped galvanized steel housing, transparent acrylic Fresnel lens cover, copper absorber tube, fiber glass insulation and weighs 98 pounds. The gross collector area is about 29.4/sup 2/ per collector. A collector assembly includes four collector units within a tracking mount array.

  2. Point-focus spectral splitting solar concentrator for multiple cells concentrating photovoltaic system

    CERN Document Server

    Maragliano, Carlo; Stefancich, Marco

    2015-01-01

    In this paper we present and experimentally validate a low-cost design of a spectral splitting concentrator for the efficient conversion of solar energy. The optical device consists of a dispersive prismatic lens made of polycarbonate designed to simultaneously concentrate the solar light and split it into its spectral components. With respect to our previous implementation, this device concentrates the light along two axes and generates a light pattern compatible with the dimensions of a set of concentrating photovoltaic cells while providing a higher concentration ratio. The mathematical framework and the constructive approach used for the design are presented and the device performance is simulated using ray-tracing software. We obtain spectral separation in the visible range within a 3x1 cm2 area and a maximum concentration of 210x for a single wavelength. The device is fabricated by injection molding and its performance is experimentally investigated. We measure an optical transmissivity above 90% in the...

  3. Leaching of copper concentrates using NaCl and soluble copper contributed by the own concentrate

    International Nuclear Information System (INIS)

    Leaching of copper concentrates using cupric chloro complexes, generated in situ by the reaction between Cu(II), aported by the soluble copper content of the concentrate, and sodium chloride in acid media was studied. The concentrate samples were obtained from mineral processing plants from Antofagasta, Chile. Chemical and mineralogical characterization from original concentrates was made. Typical variable such as a chloride concentration, soluble copper concentration, leaching time, solid percentage and temperature were studied. DRX and EDS analyzed some of the residues. the experimental results indicated that it is possible to obtain solutions having high copper content (15 to 35 g/L) and 2 to 5 g/L free acid in order to submit this solution directly to a solvent extraction stage. The leaching tests use common reactive and low cost such as sodium chloride and sulfuric acid. (Author) 16 refs

  4. Analysis of cream formation in green tea concentrates with different solid concentrations

    OpenAIRE

    Xu, Yong-Quan; Chen, Su-Qin; Yuan, Hai-Bo; Tang, Ping; Yin, Jun-Feng

    2011-01-01

    The formation of tea cream in the green tea concentrates of different solid concentrations (5, 10, 20, 30, 40, 50 and 60°Brix) was investigated. The results showed a good positive correlation (γ = 0.98, p ≤ 0.05) between the amount of tea cream and the solid concentrations from 5 to 40°Brix, while the amount of tea cream in the tea concentrates of 50 and 60°Brix decreased acutely. Total sugar, caffeine and catechins were found to be the main chemical components of tea cream in the green tea c...

  5. Spin-Stabilized Microsatellites with Solar Concentrators

    Science.gov (United States)

    Timmerman, Paul; Shields, Virgil

    2008-01-01

    A document proposes the development of spin-stabilized microsatellites powered by solar photovoltaic cells aided by solar concentrators. Each such satellite would have a cylindrical or other axisymmetric main body with solar cells mounted in a circumferential belt-like array on its exterior surface. The solar concentrator would be a halo-like outrigger cylindrical Fresnel lens array that would be deployed from and would surround the main body, connected to the main body via spokes or similar structural members. The spacecraft would be oriented with its axis of symmetry perpendicular to the line of sight to the Sun and would be set into rotation about this axis. In effect, the solar cells and concentrator would be oriented and rotated in a "rotisserie" mode, making it possible to take advantage of the concentration of solar light while preventing localized overheating of the solar cells. In addition, the mechanical stabilization inherently afforded by the rotation could be exploited as a means of passive attitude control or, at least, of reducing the requirement for active attitude control.

  6. Electro-oxidation process for molybdenum concentrates

    Institute of Scientific and Technical Information of China (English)

    FU Jian-gang; ZHONG Hong; BU Xiang-ming; WANG Fu-li

    2005-01-01

    Sodium hypochlorite was used to treat the standard molybdenum concentrates; the oxidization conditions for sodium hypochlorite were investigated, and the electro-oxidation process was performed. The results indicate that in the suitable conditions, such as temperature around 25 ℃, NaCl concentration 4.0 mol/L, mass ratio of ore slurry liquid to solid (mL/mS) 20, electric charge per gram Mo 0.522 C, pH value of original slurry 8, anodic current density 700 A·m-2 (cell potential 2.7-2.9 V), the Mo leaching rate and the current efficiency reach 98% and 36%, respectively. In order to overcome some shortages of the electro-oxidation process, such as low current efficiency, low Mo concentration in the leaching solution, ultrasonic was adopted to intensify the leaching process. The results show that the Mo leaching rate exceeds 98%, current efficiency increases from 36% to 50% and the Mo concentration in the leaching solution reaches about 60 g/L at low mL/mS of 8 and low electric charge of 0.373 C.

  7. The hybrid holographic concentrator of solar energy

    International Nuclear Information System (INIS)

    The hybrid holographic concentrator of solar energy allowing one to rise efficiency of using a solar radiation and to enlarge the factor of the radiation transformation into electric energy by use of the reradiative organic dye, incorporated into medium of holographic grating, is designed. (authors)

  8. Flows of Wet Foamsand Concentrated Emulsions

    Science.gov (United States)

    Nemer, Martin B.

    2005-01-01

    The aim of this project was is to advance a microstructural understanding of foam and emulsion flows. The dynamics of individual surfactant-covered drops and well as the collective behavior of dilute and concentrated was explored using numerical simulations. The long-range goal of this work is the formulation of reliable microphysically-based statistical models of emulsion flows.

  9. Risk in A Concentrated Export Market

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The export destination of China’s home textile products are considered to be highly concentrated. This is reflected by the statistical data of the past couple of years when, the top export destination of the following products-bedding products, curtain and towel- is United States.

  10. Formoterol concentrations in blood and urine

    DEFF Research Database (Denmark)

    Eibye, Kasper; Elers, Jimmi; Pedersen, Lars;

    2013-01-01

    We examined urinary and serum concentrations of formoterol in asthmatic and healthy individuals after a single dose of 18 μg inhaled formoterol and after repeated inhaled doses in healthy individuals. Results were evaluated using the World Anti-Doping Agency (WADA) 2012 threshold for formoterol....

  11. Magnetic flux concentrations from turbulent stratified convection

    CERN Document Server

    Käpylä, P J; Kleeorin, N; Käpylä, M J; Rogachevskii, I

    2015-01-01

    (abridged) Context: The mechanisms that cause the formation of sunspots are still unclear. Aims: We study the self-organisation of initially uniform sub-equipartition magnetic fields by highly stratified turbulent convection. Methods: We perform simulations of magnetoconvection in Cartesian domains that are $8.5$-$24$ Mm deep and $34$-$96$ Mm wide. We impose either a vertical or a horizontal uniform magnetic field in a convection-driven turbulent flow. Results: We find that super-equipartition magnetic flux concentrations are formed near the surface with domain depths of $12.5$ and $24$ Mm. The size of the concentrations increases as the box size increases and the largest structures ($20$ Mm horizontally) are obtained in the 24 Mm deep models. The field strength in the concentrations is in the range of $3$-$5$ kG. The concentrations grow approximately linearly in time. The effective magnetic pressure measured in the simulations is positive near the surface and negative in the bulk of the convection zone. Its ...

  12. Concentration of lemon pectin extract by ultrafiltration

    Directory of Open Access Journals (Sweden)

    Damián Stechina

    2012-09-01

    Full Text Available Current annual lemon production in Argentina is about 900 thousand t. 75% is used industrially to obtain pasteurized juice concentrate. Since 40 - 45 % of citrus fruit content is peel and seeds, the annual lemon residue yield is 360 thousand t. Lemon peel contains about 30% (B.S. of peptic substances with an important commercial value due to its gelling and thickening properties for food, chemical, pharmacological and cosmetic products. Membrane processes have many applications in food manufacture. The objective of this study is to analyze the influence of ultrafiltration operating variables on instant permeate flow (Fp and on the energy requirement for pectin extract concentration from lemon peel. A DDS lab module was used, lab 20-772 model with synthetic material membranes, 9 kDa, shear force, the intrinsic membrane resistance (Rm being 3*1013 m -1 . Results show that Fp decrease caused by polarization induced resistance occurrence and the influence of operating variables on Fp offer relevant data to estimate the energy requirement in relation to feeding flow at constant temperature, which may be compared to pectin concentration increase in the retained flow in relation to initial extract concentration.

  13. Electronic design of air dust concentration gauge

    International Nuclear Information System (INIS)

    A new version of isotope dust concentration gauge for monitoring airborne dust pollution of air employs a ready made personal computer as the control and processing unit in the gauge instead of specialized electronics. That solution of the gauge reduces the needed specialized electronics to a simple computer interface coupling the computer to the measuring head. This also reduced electronics of the measuring head itself, i.e. GM detector circuit, power supplies and electronic circuits to switch on/off driving motors. The functioning and operation of the gauge is controlled by the computer program that can be easily modified if needed. The computer program for the gauge enables automatic measurements of dust concentration. Up to fifty measuring cycles can be easily programmed for a day. The results of measurements are presented in the form of data collection, diagram of dust concentration distribution during one day, diagram of dust distribution during 30 successive days or diagram of average dust concentration distribution during a day which may be computed by combining data of the selected number of measurements. Recalibration of the gauge and checking up of the gauge are also carried out under the program control. (author). 6 refs, 9 figs

  14. 233-S plutonium concentration facility hazards assessment

    International Nuclear Information System (INIS)

    This document establishes the technical basis in support of Emergency Planning activities for the 233-S Plutonium Concentration Facility on the Hanford Site. The document represents an acceptable interpretation of the implementing guidance document for DOE ORDER 5500.3A. Through this document, the technical basis for the development of facility specific Emergency Action Levels and the Emergency Planning Zone is demonstrated

  15. Aerobic growth at nanomolar oxygen concentrations

    DEFF Research Database (Denmark)

    Stolper, Daniel Aaron; Revsbech, Niels Peter; Canfield, Donald Eugene

    2010-01-01

    Molecular oxygen (O2) is the second most abundant gas in the Earth’s atmosphere, but in many natural environments, its concentration is reduced to low or even undetectable levels. Although low-oxygen-adapted organisms define the ecology of low-oxygen environments, their capabilities are not fully...

  16. EVALUATING CONCENTRATION PROFILES DURING UNSTEADY MIXING

    Energy Technology Data Exchange (ETDEWEB)

    Bamberger, Judith A.; Greenwood, Margaret S.; Lawler, Bruce D.; Sundaram, S. K.; Baer, Ellen BK; Hatchell, Brian K.; Hopkins, Derek F.; Kirihara, Leslie J.; Pekour, Mikhail S.; Sande, Susan; Yu, Xiao-Ying; Zuljevic, Nino

    2010-01-01

    Pulse jet mixing tests to suspend noncohesive solids in Newtonian liquid were conducted at three geometric scales. To understand the solids suspension process an ultrasonic concentration probe was used to measure the concentration of solids in the cloud during a pulse at various elevations and radial positions. The data are being analyzed to provide a model for predicting concentration as a function of elevation. This paper presents a simple single frequency ultrasonic measurement application that demonstrates the ability of ultrasonic sensors to measure slurry concentration based on signal attenuation. Sensor calibration data show that ultrasonic signal attenuation is proportional to the applied frequency and to the slurry volume fraction. Real-time measurements of ultrasonic signal attenuation were used to track the process of slurry mixing using single sensors and sensor arrays. Comparison of means of the ultrasonic measurements with means obtained from discrete extractive measurements show that the distributions overlap and cannot be statistically distinguished. The real-time ultrasonic sensor can be used as a primary measurement method or to reduce reliance upon extractive methods to measure slurry density.

  17. Concentration of technetium by marine organisms

    International Nuclear Information System (INIS)

    Accumulation and excretion of technetium by marine organisms were observed in radioisotope tracer experiments to determine concentration factors for estimating radiation dose to humans from radioactive pollution of marine environments. Marine fish, crustaceans, mollusks, echinoderms, and seaweeds were reared in sea water labeled with 95mTc to observe uptake from sea water. The organisms were then transferred into unlabeled sea water for depuration experiments. Concentration factors were calculated from uptake and excretion rates. Also considered was the contribution of food-chain transfer of technetium, observed by administering labeled seaweeds to mollusks or echinoderms. Low accumulations were shown by fish, crustaceans, pelecypods and cephalopods, whereas high concentration factors were observed in gastropods and seaweeds. Species specificity or specific accumulation in special organs or tissues was not evident except in seaweed, where the difference was clearly species-associated. Relatively high rates of technetium retention were observed in the organisms administered labeled seaweed. The higher concentrations observed in gastropods, compared to those in pelecypods, were thought to result from different feed habits. The adaptability of some species as indicator organisms for monitoring 99Tc in sea water was recognized, but the contribution of technetium to radiation dose was considered insignificant

  18. INFLUENCE OF FILLING WATER ON AIR CONCENTRATION

    Institute of Scientific and Technical Information of China (English)

    WU Jian-hua; MA Fei; DAI Hui-chao

    2011-01-01

    The filling water inside the cavity below an aerator occurs for the flow of low Froude number or the small bottom slope of a spillway.The aerator may cease to protect against cavitation damages,and may even act as a generator of cavitation if it is fully filled by water.The experiments were conducted to investigate the influences of the geometric parameters,and then the filling water on the air concentration.The results show that the filling water,or the net cavity length,is closely related to the plunging jet length for a given aerator,and the air concentration at some section is proportional to the ratio Ln/Lj at a fixed Lj for different geometric parameters of aerators.Secondly,at the same ratio of Ln / Lj,the aerator with a larger height or a larger angle of ramp,or a larger bottom slope,would have a larger plunging jet length,and then a larger net cavity length based on the ratio of Ln / Lj.As a result,the large space of cavity,or the high air concentration of the flow could be obtained although the filling water increases also based on the fact that Lf=Lj- Ln.It is the space of the cavity that is the dominant factor to affect the air concentration of the flow.

  19. A facile surfactant critical micelle concentration determination

    OpenAIRE

    Cai, Lifeng; Gochin, Miriam; Liu, Keliang

    2011-01-01

    Liquid surface curvature variations in microplate wells due to different liquid surface tension cause significant signal change in spectroscopic measurement using a plate reader with a vertical detecting light beam. The signals have been quantitated and used to develop a method for facile surfactant critical micelle concentration determination.

  20. Effect of concentration polarization on permselectivity.

    Science.gov (United States)

    Abu-Rjal, Ramadan; Chinaryan, Vahe; Bazant, Martin Z; Rubinstein, Isaak; Zaltzman, Boris

    2014-01-01

    In this paper, the variation of permselectivity in the course of concentration polarization is systematically analyzed for a three-layer membrane system consisting of a nonperfectly permselective ion exchange membrane, homogeneous or heterogeneous, flanked by two diffusion layers of a binary univalent electrolyte. For a heterogeneous membrane, an ionic transport model is proposed, which is amenable to analytical treatment. In this model, assuming a constant fixed charge in the membrane and disregarding water splitting, the entire transport problem is reduced to solution of a single algebraic equation for the counterion transport number. It is concluded that for both types of membrane the concentration polarization may significantly affect the permselectivity of the system through the effects of the induced nonuniformity of the coion diffusion flux in the membrane (convexity of the coion concentration profile) and varying membrane-solution interface concentration. While the former is significant for low membrane fixed charge density, for a heterogeneous membrane, the latter might be considerably affected by the flux focusing effect at the permeable membrane segments. PMID:24580222

  1. 21 CFR 155.191 - Tomato concentrates.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Tomato concentrates. 155.191 Section 155.191 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION CANNED VEGETABLES Requirements for Specific Standardized Canned Vegetables §...

  2. Concentration Tests - Issues of Computer Adaptation

    Czech Academy of Sciences Publication Activity Database

    Květon, Petr; Klimusová, Helena

    Lanškroun: GOSC Group, s.r.o., 2001. s. 195. [The Tenth European Congress on Work and Organizational Psychology . 16.05.2001-19.05.2001, Praha] Institutional research plan: CEZ:AV0Z7025918 Keywords : Concentration Test * Computer Based Assessment Subject RIV: AN - Psychology

  3. 40 CFR 264.94 - Concentration limits.

    Science.gov (United States)

    2010-07-01

    ... 264.94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Releases From Solid Waste Management Units § 264.94 Concentration limits. (a) The Regional Administrator...

  4. Nucleation modes in sharp concentration gradients

    Energy Technology Data Exchange (ETDEWEB)

    Hodaj, F.; Desre, P.J. [LTPCM-UMR CNRS/INPG/UJF, Saint Martin d`Heres (France); Gusak, A.M.; Kovalchuk, A.O. [Cherkassy State Univ. (Ukraine). Dept. of Theoretical Physics

    1998-12-31

    Reaction kinetics in bimetallic multilayers have demonstrated that sharp unidirectional concentration gradient, which develop as interdiffusion proceeds at the interface are able to delay or to suppress nucleation of intermetallics. It has been found that the existence of a critical gradient beyond which nucleation is inhibited is strongly dependent on the mechanism of formation of the embryo. A mechanism of nucleation under concentration gradient ({gradient}c) is proposed and treated on the basis of the Fokker-Planck equation for the distribution in the size space. The influence of the aspect ratio of the embryo on the critical concentration gradient is also studied. Due to the fluctuations of the embryo shape, it is shown that the minimization of the thermodynamic potential leading to the aspect ratio of the embryo is only significant beyond a certain value of the concentration gradient. Application is presented to the nucleation of the compound Ni{sub 10}Zr{sub 7} in an amorphous layer Ni-Zr.

  5. RHEOLOGY OF CONCENTRATED SOLUTIONS OF HYPERBRANCHED POLYESTERS

    Science.gov (United States)

    The solution rheology of different generations of hyperbranched polyesters in N-methyl-2- pyrrolidinone (NMP) solvent was examined in this study. The solutions exhibited Newtonian behavior over a wide range of polyester concentrations. Also, the relative viscosities of poly(amido...

  6. 137Cs concentration in stingray (Dasyatis akajei)

    International Nuclear Information System (INIS)

    137Cs, which is of great interest and importance as an indicator of radioactive pollution in marine environments, is one of the long-lived artificial radio-nuclides introduced by the atmospheric deposition of debris from nuclear explosions mainly before 1962. For the estimation of effects of the effluents from nuclear facilities, it is necessary to know the natural variations in the concentration of 137Cs and factors affecting variations in marine organisms. We observed positive correlation between growth and 137Cs in 4 species among 14 major teleost species from fishing grounds along the coast of Japan. No increase in 137Cs concentration with increase of growth was observed in 2 species. In the remaining species no specific correlation is observed. These differences in the patterns were dependent on a change of feed habits with growth. As little is known of the 137Cs concentration in selachian we have investigated the natural variations of 137Cs in stingray. The correlation between growth and the concentration of 137Cs in stingray will be discussed. (author)

  7. KTH-1 tantalum and niobium concentration meter

    International Nuclear Information System (INIS)

    The KTH-1 tantalum and niobium concentration meter is intended for rapid analysis of technological samples in shop and works laboratories and for the automatic continuous determination of Ta or Nb concenration in flow technological solutions. The analysis time is less than 30 min, including sample preparation and processing of measurement results. The instrument is bases on absorption jump X-ray analysis

  8. AUDIT MARKET CONCENTRATION – EVIDENCE FROM CROATIA

    Directory of Open Access Journals (Sweden)

    Sanja Sever Mališ

    2015-12-01

    Full Text Available Statutory audit is designated to protect the public interest and has a significant impact on the overall economy. There are concerns that the Big Four audit firms have become too dominant and that the collapse of one of these firms would disrupt the whole financial system. In terms of revenues received, the total market share of the Big Four audit firms for listed companies exceeds 90% in a vast majority of European Union Member States. Prior studies have shown that high audit market concentration limits the choice of auditor for large companies and sets a high barrier of entry for mid-tier audit firms, while the effect on audit quality and audit fees is still unclear. Therefore, the regulators are considering reforms to dilute the Big Four’s dominance and improve competition in the audit market. The paper reviews the proposed and implemented measures that are the most common, together with their advantages and drawbacks. In addition, the characteristics of the audit market in Croatia are investigated, with a focus on market concentration measured by standard measures such as the Concentration rate, the Herfindahl Hirschman Index and the Gini coefficient. According to market shares based on total clients’ assets and revenues, the audit market for listed companies is moderately to highly concentrated, with a decrease in the five-year period (2013 compared to 2008.

  9. Advertising and Concentration in the Brewing Industry

    DEFF Research Database (Denmark)

    Madsen, Erik Strøjer; Wu, Yanqing

    2014-01-01

    The paper tracks the development in industry concentrations from 2002 to 2012, discusses some of the main drivers behind this development and points to economies of scale in advertising as a main pay-off from mergers and acquisitions. Using firm-level data both from the American market...

  10. Concentrating Solar Power Commercial Application Study

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2009-10-01

    This report has been prepared in response to section 603(b) of the Energy Independence and Security Act of 2007, (Pub. L. No. 110-140), which states that “…the Secretary of Energy shall transmit to Congress a report on the results of a study on methods to reduce the amount of water consumed by concentrating solar power systems.”

  11. Control of Concentration during Academic Tasks.

    Science.gov (United States)

    Collins, Karen W.; And Others

    1981-01-01

    Three strategies for controlling concentration during academic tasks were evaluated: (1) self-initiated relaxation; (2) self-coaching; and (3) a combination of the first two types. Results indicated that the third strategy, significantly facilitated some aspects of academic performance. (Author/GK)

  12. Maximum phytoplankton concentrations in the sea

    DEFF Research Database (Denmark)

    Jackson, G.A.; Kiørboe, Thomas

    2008-01-01

    in the North Atlantic as part of the Bermuda Atlantic Time Series program as well as data collected off Southern California as part of the Southern California Bight Study program. The observed maximum particulate organic carbon and volumetric particle concentrations are consistent with the...

  13. Concentrated insulins: the new basal insulins

    Directory of Open Access Journals (Sweden)

    Lamos EM

    2016-03-01

    Full Text Available Elizabeth M Lamos,1 Lisa M Younk,2 Stephen N Davis3 1Division of Endocrinology, Diabetes and Nutrition, 2Department of Medicine, University of Maryland School of Medicine, 3Department of Medicine, University of Maryland Medical Center, Baltimore, MD, USA Introduction: Insulin therapy plays a critical role in the treatment of type 1 and type 2 diabetes mellitus. However, there is still a need to find basal insulins with 24-hour coverage and reduced risk of hypoglycemia. Additionally, with increasing obesity and insulin resistance, the ability to provide clinically necessary high doses of insulin at low volume is also needed. Areas covered: This review highlights the published reports of the pharmacokinetic (PK and glucodynamic properties of concentrated insulins: Humulin-R U500, insulin degludec U200, and insulin glargine U300, describes the clinical efficacy, risk of hypoglycemic, and metabolic changes observed, and finally, discusses observations about the complexity of introducing a new generation of concentrated insulins to the therapeutic market. Conclusion: Humulin-R U500 has a similar onset but longer duration of action compared with U100 regular insulin. Insulin glargine U300 has differential PK/pharmacodynamic effects when compared with insulin glargine U100. In noninferiority studies, glycemic control with degludec U200 and glargine U300 is similar to insulin glargine U100 and nocturnal hypoglycemia is reduced. Concentrated formulations appear to behave as separate molecular entities when compared with earlier U100 insulin analog compounds. In the review of available published data, newer concentrated basal insulins may offer an advantage in terms of reduced intraindividual variability as well as reducing the injection burden in individuals requiring high-dose and large volume insulin therapy. Understanding the PK and pharmacodynamic properties of this new generation of insulins is critical to safe dosing, dispensing, and administration

  14. Radioimmunoassay of thyrotropin concentrated from serum

    Energy Technology Data Exchange (ETDEWEB)

    Nisula, B.C.; Louvet, J.P.

    1978-05-01

    A method for concentrating human TSH (hTSH) from serum for use in RIAs is described. The method takes advantage of the affinity of the plant lectin, concanavalin A, for the carbohydrate portion of the hTSH molecule. The hTSH from 2.5 ml serum was adsorbed to concanavalin A covalently linked to sepharose and then radioimmunoassayed using the hTSH antiserum and hTSH for iodination distributed by the National Pituitary Agency. For the RIA standard curve, the hTSH reference preparation was concentrated from a serum wwith undetectable hTSH in order to correct for recovery and to control for nonspecific effects. The percentage of serum hTSH extracted from 2.5 ml serum with the concentration procedure was 76.6 +- 3.4% (mean +- SD). The coefficient of correlation between serum hTSH, determined with the concentration procedure, and serum hTSH determined without was 0.979 (P < 0.001). Over 95% of normal adult men and women had detectable levels of serum hTSH, ranging from < 0.56 to 4.0 ..mu..U/ml. The mean of detectable serum hTSH levels in normal adult women (n = 11) was 1.54 +- 1.03 ..mu..U/ml (mean +- SD) and in normal men (n = 9) was 2.02 +- 1.15 ..mu..U/ml (mean +- SD). Clinically hyperthyroid patients with diffuse and nodular toxic goiters (n = 8) and patients with hypothyroidism secondary to pituitary disease (n = 6), four of whom were taking replacement doses of thyroid hormone, had undetectable serum hTSH levels. Serum hTSH in patients with primary hypothyroidism uniformly exceeded the normal range. This hTSH concentrating procedure enhances the effective sensitivity and, therefore, the clinical utility of the RIA for hTSH in serum.

  15. High Concentration Suspensions Under Strong Tidal Flows

    Science.gov (United States)

    Kineke, G. C.; Milligan, T. G.; Heath, K. M.; Law, B. A.

    2006-12-01

    An experiment investigating the influence of high-concentration suspensions of fine sediments (fluid muds) on a quasi-steady flow was carried out in the Petitcodiac River, Moncton, New Brunswick, Canada in August 2006. Concurrent measurements of fluid properties (salinity, temperature, density), suspended-sediment concentration, current velocity and shear were made throughout the water column over portions of several tidal cycles. The Petitcodiac was chosen because of consistently high suspended-sediment concentrations (0.5- >200 g/L) and large tidal range (>4 m) producing strong current velocities (> 1.5 m/s). Thus the Peticodiac serves as an ideal natural flume for examining the behavior of muddy suspensions under both accelerating and decelerating flows. Instrumentation included a profiling package with paired electromagnetic current meters mounted 0.6 m apart, a CTD, and an Optical Backscatterance Sensor with a pump system for in situ calibrations. Approximately 1.5 hours after the passage of the tidal bore and a fully mixed turbulent flow, the water column begins to stratify and a high concentration bottom layer forms persisting through the ensuing ebb. Measured suspended-sediment concentrations reached 286 g/L at the bottom and low shear rates of 0.13 s-1 in the upper water column increased to ~0.5 s-1 through the lutocline 1 m above the bed, and decreased to approximately 0 within the fluid mud. Analysis is in progress and the data set provides an excellent means to test threshold conditions regarding suppression of turbulence by sediment-induced stratification and the carrying capacity of turbulent flows.

  16. Radionuclides concentration in foods in Peninsular Malaysia

    International Nuclear Information System (INIS)

    The concentrations of natural radionuclides (U-238, Th-232, Ra-226, Ra-228 and K-40) and artificial radionuclides (Cs-137) in fresh, dried and cooked foodstuffs from 30 major towns in Peninsular Malaysia were determined by gamma spectrometry system and Instrumental Neutron Activation Analysis (INAA) technique. A total of 232 samples representing a typical Malaysian community diet were analysed. The results showed that most of the samples contained only natural radionuclides. The percentage of radionuclides detected in the samples were found about 2% for U-238, 9% for Th-232, 49% for Ra-226, 77% for Ra-228, 99% for K-40 and 15% for Cs-137. The radionuclide concentrations were in the ranges of <6.1 - 29.3, <2.0 - 55.8, <0.1 - 34.4, <0.1 - 41, <0.1- 2552.3 and < 0.1 - 6.6 Bq/Kg dry weight for U-238, Th-232, Ra-226, Ra-228 and K-40 and Cs-137 respectively. The study revealed that most of the foodstuffs did not contain U-238. Lentils were found to contain significant concentration of Th-232 (4 - 49 Bq/kg) and can be considered as thorium accumulators. The concentrations of Ra-226 and Ra-228 in leafy vegetables were higher than the fruit and root vegetables. These data can be used as a reference for future food radioactivity monitoring. As edible mushroom and fern had high concentrations of Cs-137, indicating their high ability to accumulate Cs-137, they could be used as indicator plants in the event of radioactive fall outs

  17. Magnetic flux concentrations from turbulent stratified convection

    Science.gov (United States)

    Käpylä, P. J.; Brandenburg, A.; Kleeorin, N.; Käpylä, M. J.; Rogachevskii, I.

    2016-04-01

    Context. The formation of magnetic flux concentrations within the solar convection zone leading to sunspot formation is unexplained. Aims: We study the self-organization of initially uniform sub-equipartition magnetic fields by highly stratified turbulent convection. Methods: We perform simulations of magnetoconvection in Cartesian domains representing the uppermost 8.5-24 Mm of the solar convection zone with the horizontal size of the domain varying between 34 and 96 Mm. The density contrast in the 24 Mm deep models is more than 3 × 103 or eight density scale heights, corresponding to a little over 12 pressure scale heights. We impose either a vertical or a horizontal uniform magnetic field in a convection-driven turbulent flow in set-ups where no small-scale dynamos are present. In the most highly stratified cases we employ the reduced sound speed method to relax the time step constraint arising from the high sound speed in the deep layers. We model radiation via the diffusion approximation and neglect detailed radiative transfer in order to concentrate on purely magnetohydrodynamic effects. Results: We find that super-equipartition magnetic flux concentrations are formed near the surface in cases with moderate and high density stratification, corresponding to domain depths of 12.5 and 24 Mm. The size of the concentrations increases as the box size increases and the largest structures (20 Mm horizontally near the surface) are obtained in the models that are 24 Mm deep. The field strength in the concentrations is in the range of 3-5 kG, almost independent of the magnitude of the imposed field. The amplitude of the concentrations grows approximately linearly in time. The effective magnetic pressure measured in the simulations is positive near the surface and negative in the bulk of the convection zone. Its derivative with respect to the mean magnetic field, however, is positive in most of the domain, which is unfavourable for the operation of the negative

  18. Effects of light intensity, oxygen concentration, and carbon dioxide concentration on photosynthesis in algae.

    Science.gov (United States)

    Pope, D H

    1975-03-01

    The effects of various combinations of light intensity, oxygen concentration, and CO2 concentration on photosynthesis and growth in several algal types were studied. The results suggest the following. (1) Different algae show different responses to high oxygen concentrations and high light intensities. (2) Inhibition of photosynthesis (CO2 fixation and growth), if seen, increases with increasing oxygen concentration and with increasing light intensity (at light intensities greater than saturation). (3) The inhibition of net photosynthesis observed cannot be attributed to high light intensity alone. (4) The inhibition cannot be attributed to increased rates of excretion of organic materials under conditions of high oxygen concentration and high light intensity. (5) Increased concentrations of CO2 can decrease the effect of high oxygen and light in some algae. (6) The decrease in net photosynthesis observed is probably the result of photorespiration. (7) The effect of light intensity, oxygen concentration, or CO2 concentration on algal photosynthesis should not be studied without considering the effect of the other factors. Some implications of these results, as related to primary productivity measurements, are also discussed. PMID:24241158

  19. Linear concentration system; Sistema de concentracion lineal

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Lugo, J.I; Leon Rovira, N; Aguayo Tellez, H [Instituto Tecnologico y de Estudios Superiores de Monterrey, Monterrey, Nuevo Leon (Mexico)]. E-mails: a00812662@itesm.mx; noel.leon@itesm.mx; haguayo@itesm.mx

    2013-03-15

    Solar linear concentration technologies to generate high temperatures are limited to the ranges of 200 to 500 degrees Celsius. While its performance has been tested through prototypes and pilot plants around the world, there are still areas of opportunity that can be exploited to obtain a linear concentration that achieves temperatures above this range in order to have a better use of the available solar energy. Because of this: It is possible to develop a linear concentration system that can track the sun with minimal movement of the absorber-receiver while maintaining temperatures above 850 degrees Celsius sufficient for industrial processes that require that temperature. The methodology consists of a series of stages (conceptual design, simulation, evaluation, development concept, results and validation) through which concepts are generated that allow design and evaluation of solar concentrator configurations with the help of simulation software. We have designed a linear parabolic concentrating system which comprises a set of mirrors segments with different focal lengths that works within the range of 600 degrees Celsius; however, it is advancing in the development of a double concentration to reach 850 degrees Celsius. [Spanish] Las tecnologias de concentracion lineal solar para generar altas temperaturas se ven limitadas a los rangos de 200 a 500 grados centigrados. Si bien su funcionamiento ha sido probado a traves de prototipos y plantas piloto alrededor del mundo, aun existen areas de oportunidad que pueden ser aprovechadas para obtener un sistema de concentracion lineal que permita alcanzar temperaturas mayores a este rango para asi tener un mejor aprovechamiento de la energia solar disponible. Debido a esto: Es posible desarrollar un sistema de concentracion lineal capaz de seguir la trayectoria del Sol con minimo movimiento del absorbedor-recibidor al mismo tiempo que mantiene temperaturas superiores a los 850 grados centigrados suficientes para

  20. On the pelletizing of sulfide molybdenite concentrate

    International Nuclear Information System (INIS)

    Investigation results are discussed on the process of pelletizing with the use of various binders (water, syrup, sulfite-alcoholic residue and bentonite) for flotation sulfide molybdenite concentrate (∼84 % MoS2) of the Mongolian deposit. It is established that with the use of syrup rather strong pellets (>300 g/p) of desired size (2-3 mm) can be obtained at a binder flowrate of 1 kg per 100 kg of concentrate. The main advantage of using syrup instead of bentonite lies in the fact that in this instance no depletion of a molybdenum calcine obtained by oxidizing roasting of raw ore takes place due to syrup complete burning out. This affects positively subsequent hydrometallurgical conversion because of decreasing molybdenum losses with waste cakes

  1. Environmental natural radioactivity concentrations of Tekirdag

    International Nuclear Information System (INIS)

    Full text: In this study, the environmental natural radioactivity concentrations of Tekirdag, a city in the region of Marmara in Turkey, have been measured. Gamma spectrometric analysis of the soil samples collected from 40 points of Tekirdag was performed by using an HPGe detector and the radionuclide concentrations of the decay products of 238U and 232Th series, 40K and 137Cs were determined. Gross alpha and gross beta activities of the water samples taken from municipal supplies, springs, wells and fountains were performed by using the Berthold, LB770-PC 10, a gas-flow proportional counter. Gamma exposure dose rates were measured by using an Eberline Smart Portable scintillation detector and the annual effective dose equivalents caused by exposure gamma dose rates were calculated

  2. Big Crunch-based omnidirectional light concentrators

    International Nuclear Information System (INIS)

    Omnidirectional light concentration remains an unsolved problem despite such important practical applications as the design of efficient mobile photovoltaic cells. Recently developed optical black hole designs offer partial solutions to this problem. However, even these solutions are not truly omnidirectional since they do not exhibit a horizon, and at large enough incidence angles the light may be trapped into quasi-stationary orbits around such imperfect optical black holes. Here, we propose and realize experimentally another gravity-inspired design of a broadband omnidirectional light concentrator based on the cosmological Big Crunch solutions. By mimicking the Big Crunch spacetime via a corresponding effective optical metric, we make sure that every photon world line terminates in a single point. (paper)

  3. Intracerebral source generators characterizing concentrative meditation.

    Science.gov (United States)

    Lavallee, Christina F; Hunter, Mathew D; Persinger, Michael A

    2011-05-01

    Previous researchers have studied meditation practices as a means to understand consciousness as well as altered states of consciousness. Various meditation techniques, such as Transcendental Meditation (TM) and Qigong, have been explored with source localization tools; however, the concentrative meditation technique has yet to be fully studied in this manner. The current study demonstrates findings, which outline differential activation in a self-referential default network during meditation in participants who espouse themselves as regular concentrative meditation practitioners, as well as comparisons with a control group practicing a modified version of the relaxation response. The results are compared with other putative experimental findings employing other meditation techniques, and the findings outlined in the current study are discussed with respect to changes in perceptual awareness often reported by meditators. PMID:21350845

  4. Characterization of a low concentrator photovoltaics module

    Energy Technology Data Exchange (ETDEWEB)

    Butler, B.A. [Department of Physics, Nelson Mandela Metropolitan University, P. O. Box 77000, Port Elizabeth 6031 (South Africa); Dyk, E.E. van, E-mail: ernest.vandyk@nmmu.ac.za [Department of Physics, Nelson Mandela Metropolitan University, P. O. Box 77000, Port Elizabeth 6031 (South Africa); Vorster, F.J.; Okullo, W.; Munji, M.K. [Department of Physics, Nelson Mandela Metropolitan University, P. O. Box 77000, Port Elizabeth 6031 (South Africa); Booysen, P. [Setsolar, P. O. Box 15934, Panorama 7506 (South Africa)

    2012-05-15

    Low concentration photovoltaic (LCPV) systems have the potential to reduce the cost per kWh of electricity compared to conventional flat-plate photovoltaics (PV) by up to 50%. The cost-savings are realised by replacing expensive PV cells with relatively cheaper optical components to concentrate incident solar irradiance onto a receiver and by tracking the sun along either 1 axis or 2 axes. A LCPV module consists of three interrelated subsystems, viz., the optical, electrical and the thermal subsystems, which must be considered for optimal module design and performance. Successful integration of these subsystems requires the balancing of cost, performance and reliability. In this study LCPV experimental prototype modules were designed, built and evaluated with respect to optimisation of the three subsystems and overall performance. This paper reports on the optical and electrical evaluation of a prototype LCPV module.

  5. Vacuum drying plant for evaporator concentrates

    International Nuclear Information System (INIS)

    Volume reduction systems applied to evaporator concentrates in PWR and BWR save a significant amount of drums. The concentration to dry product is a technique that reaches the maximum volume reduction, compared to conventional techniques (cementation, polymerisation). Four Spanish N.P.P. (3 PWR and 1 BWR) have selected ENSA's process by means of fixed ''in drum vacuum drying system''. A 130-litre steel drum is used for drying without any additional requirement except vacuum resistance. This steel drum is introduced into a standard 200-litre drum. Five centimeters concrete shielding cylinder exists between both drums. Final package is classified as 19 GO according to ENRESA's acceptance code (dry waste with 5 cm concrete between 130-l and 200-l drum). The generation of cemented waste in five N.P.P. versus dried waste will be reduced 83%. This reduction will save a considerable amount in disposal costs. (authors)

  6. Characterization of a low concentrator photovoltaics module

    International Nuclear Information System (INIS)

    Low concentration photovoltaic (LCPV) systems have the potential to reduce the cost per kWh of electricity compared to conventional flat-plate photovoltaics (PV) by up to 50%. The cost-savings are realised by replacing expensive PV cells with relatively cheaper optical components to concentrate incident solar irradiance onto a receiver and by tracking the sun along either 1 axis or 2 axes. A LCPV module consists of three interrelated subsystems, viz., the optical, electrical and the thermal subsystems, which must be considered for optimal module design and performance. Successful integration of these subsystems requires the balancing of cost, performance and reliability. In this study LCPV experimental prototype modules were designed, built and evaluated with respect to optimisation of the three subsystems and overall performance. This paper reports on the optical and electrical evaluation of a prototype LCPV module.

  7. Nonlinear interaction of the concentrated waves

    International Nuclear Information System (INIS)

    The nonlinear problem of the wave propagation is considered. In addition to Kerr nonlinearity the question of the existence of concentrated solutions is analyzed for the threshold and saturable nonlinearity. It is shown that both in the case of threshold nonlinearity, and in the case of saturable nonlinearity solitary waves – concentrated solutions of the corresponding wave equations exist. For the nonlocal nonlinearity, it is taken into account that the diffusion process transforms the interaction of the electromagnetic field with the environment. This phenomenon is described by the system of differential equations including the equation for the perturbation of the dielectric permittivity. The mathematical problem is reduced to the eigenvalue problem for nonlinear integro-differential equation of Hartree type. The computational procedure is constructed

  8. Concentration Distribution in a Mixing Ventilated Room

    DEFF Research Database (Denmark)

    Jensen, Rasmus Lund; Pedersen, D.N.; Nielsen, Peter V.;

    2001-01-01

    Today there is an increasing focus on the importance of a proper ventilation system to obtain good working conditions in the term of air and thermal quality to ensure high productivity. Different ventilation principles are used, e.g., mixing ventilation and displacement ventilation. In order to...... that the air is fully mixed. The objective of this work is to determine the influence of the location of a pollutant, temperature differences and whether the room is furnished or not. It is also investigated if it is sufficient to determine the mean concentration in the room to determine the personal...... exposure. Full scale experiments along with a breathing thermal manikin (BTM) have been used. The results show that the location of the sources is of great importance, just as well as temperature differences. Furthermore, the concentration in the breathing zone showed large differences throughout the room....

  9. Thin photovoltaic modules at ultra high concentration

    Science.gov (United States)

    Pérez-Higueras, Pedro; Ferrer-Rodríguez, Juan Pablo; Shanks, Katie; Almonacid, Florencia; Férnández, Eduardo F.

    2015-09-01

    A new design concept of high concentration photovoltaic (HCPV) module is studied both by ray-tracing simulation and by building a prototype. This set-up is based on the idea of concentrating sunlight from different optical units to a single commercial multi-junction solar cell, which is located in a different plane than that of the primary optics (e.g. Fresnel lenses). A two-optical-unit set-up, as a first approach, is built and measured with the solar simulator "Helios 3198". These results are compared to the measurement results of the single-unit of one Fresnel lens and the same solar cell. The feasibility of this new design has been confirmed theoretically and practically.

  10. Methods and systems for concentrated solar power

    Science.gov (United States)

    Ma, Zhiwen

    2016-05-24

    Embodiments described herein relate to a method of producing energy from concentrated solar flux. The method includes dropping granular solid particles through a solar flux receiver configured to transfer energy from concentrated solar flux incident on the solar flux receiver to the granular solid particles as heat. The method also includes fluidizing the granular solid particles from the solar flux receiver to produce a gas-solid fluid. The gas-solid fluid is passed through a heat exchanger to transfer heat from the solid particles in the gas-solid fluid to a working fluid. The granular solid particles are extracted from the gas-solid fluid such that the granular solid particles can be dropped through the solar flux receiver again.

  11. Big Crunch-based omnidirectional light concentrators

    CERN Document Server

    Smolyaninov, Igor I

    2014-01-01

    Omnidirectional light concentration remains an unsolved problem despite such important practical applications as design of efficient mobile photovoltaic cells. Optical black hole designs developed recently offer partial solution to this problem. However, even these solutions are not truly omnidirectional since they do not exhibit a horizon, and at large enough incidence angles light may be trapped into quasi-stationary orbits around such imperfect optical black holes. Here we propose and realize experimentally another gravity-inspired design of a broadband omnidirectional light concentrator based on the cosmological Big Crunch solutions. By mimicking the Big Crunch spacetime via corresponding effective optical metric we make sure that every photon world line terminates in a single point.

  12. Corona Discharge Influences Ozone Concentrations Near Rats

    Energy Technology Data Exchange (ETDEWEB)

    Goheen, Steven C.; Gaither, Kari A.; Anantatmula, Shantha M.; Mong, Gary M.; Sasser, Lyle B.; Lessor, Delbert L.

    2004-02-26

    Ozone is produced by corona discharge in air. Its production is enhanced near grounded water. Whether grounded animals behave like grounded water, producing more ozone was investigated. Rats were exposed to corona discharge in a plastic cage. The concentration of ozone in the gas phase was monitored. The ozone concentration exceeded ambient levels only in the presence of corona discharge and either rats or water. When water or rats were exposed to corona discharge, ozone levels were more than 10 times higher than controls. Ozone levels increased rapidly with applied voltage. There was also a correlation between the distance of the corona needle to the rats and the amount of ozone produced. As the distance increased, ozone production decreased. These results are discussed in relation to the potential exposure of mammals to ozone in the vicinity of corona discharge and electric fields.

  13. Radon concentration measurements in therapeutic spring water

    International Nuclear Information System (INIS)

    It is believed that people undergoing a curative cycle in a given spa, may receive a dose in the range of 400 mSv/year which is many times the average annual dose so that their risk of lung cancer may increase by 3% or more. To determine the risk due to the natural radioactivity, of the most frequented spas in Budapest (H), we selected four and some others located on the country side being of particular interest. Results of the radon concentration in spring water are presented, with the evidence that some spas have a high radon concentration. We conclude that patients receiving treatment may be exposed to an additional dose in the range of 29-76 mSv/year that at the bronchia could be between 445-1182 mSv/year. (authors). 6 refs., 2 figs., 2 tabs

  14. Thermal Nature of Concentration Limits of Combustion

    Science.gov (United States)

    Sabdenov, K. O.; Baitasov, T. M.

    2015-05-01

    An explanation is proposed for the concentration limits of slow combustion of gas mixtures due to the diffusional-thermal instability of a flame and the leading role of the thermal effect of mixture combustion. Basic to this explanation are the following experimental facts obtained for a wide class of mixtures: the concentration limits of slow combustion of a mixture and of its detonation are closely coinciding and depend strongly on the stoichiometric composition of mixture; there is an approximate symmetry relation between the upper and lower combustion limits. It is shown that the flame temperature of gas mixtures depends on their stoichiometric composition and that as their stoichiometric relation deviates from unity, the state of mixture combustion approaches the stability threshold beyond which a stationary flame cannot exist.

  15. Spot Spraying Reduces Herbicide Concentrations in Runoff.

    Science.gov (United States)

    Melland, Alice R; Silburn, D Mark; McHugh, Allen D; Fillols, Emilie; Rojas-Ponce, Samuel; Baillie, Craig; Lewis, Stephen

    2016-05-25

    Rainfall simulator trials were conducted on sugar cane paddocks across dry-tropical and subtropical Queensland, Australia, to examine the potential for spot spraying to reduce herbicide losses in runoff. Recommended rates of the herbicides glyphosate, 2,4-D, fluoroxypyr, atrazine, and diuron were sprayed onto 0, 20, 40, 50, 70, or 100% of the area of runoff plots. Simulated rainfall was applied 2 days after spraying to induce runoff at one plant cane and three ratoon crop sites. Over 50% of all herbicides were transported in the dissolved phase of runoff, regardless of the herbicide's sediment-water partition coefficient. For most sites and herbicides, runoff herbicide concentrations decreased with decreasing spray coverage and with decreasing herbicide load in the soil and cane residues. Importantly, sites with higher infiltration prior to runoff and lower total runoff had lower runoff herbicide concentrations. PMID:26479195

  16. Experimental Study on Concentrating Apple Juice by Microwave

    OpenAIRE

    Ge Xinfeng

    2014-01-01

    In order to use microwave in concentrating apple juice and find the law of the relationship between the microwave and the concentrating effect and apply microwave to concentrate the apple juice, studied the apple juice concentrating process by microwave. The results show, microwave can effectively remove the moisture in apple juice and the concentrating quality and concentrating effect would not be affected. The process provides the basis that the microwave is used in apple juice concentrating.

  17. Tipping point analysis of atmospheric oxygen concentration

    Energy Technology Data Exchange (ETDEWEB)

    Livina, V. N.; Forbes, A. B. [National Physical Laboratory, Teddington TW11 0LW (United Kingdom); Vaz Martins, T. M. [John Innes Centre, Norwich NR4 7UH (United Kingdom)

    2015-03-15

    We apply tipping point analysis to nine observational oxygen concentration records around the globe, analyse their dynamics and perform projections under possible future scenarios, leading to oxygen deficiency in the atmosphere. The analysis is based on statistical physics framework with stochastic modelling, where we represent the observed data as a composition of deterministic and stochastic components estimated from the observed data using Bayesian and wavelet techniques.

  18. Nitrate Concentration in Groundwater in Isfahan Province

    OpenAIRE

    S.F Mousavi; M. Afyuni; A. Jafari Malekabadi; Khosravi, A.

    2004-01-01

    In recent decades, the use of nitrogen fertilizers has increased irrespective of their effects on soil properties, agricultural products and, particularly, on environmental pollution. Nitrate easily leaches from soils into groundwater. The objective of this study was to determine temporal and spatial nitrate concentrations in groundwater in agricultural, industrial and urban regions in some parts of Isfahan Province. Water samples were collected monthly from 75 agricultural, industrial, and u...

  19. Structural Health Monitoring for Concentrated Solar Plants

    OpenAIRE

    Gómez Muñoz, Carlos Quiterio; Trapero Arenas, Juan Ramón; García Márquez, Fausto Pedro

    2014-01-01

    Renewable energy is being one of the options to cover the demand due to the environmental restrictions. One of the most relevant renewable energy sources is the solar energy, where the concentrated solar power is nowadays the source that is getting more importance. The correct performance of solar receiver is crucial because its failure can result in significant costs and availability of the energy service. Non-destructive testing is broadly used in structural health monitoring systems in ord...

  20. Photovoltaic concentrator assembly with optically active cover

    Science.gov (United States)

    Plesniak, Adam P

    2014-01-21

    A photovoltaic concentrator assembly that includes a housing that defines an internal volume and includes a rim, wherein the rim defines an opening into the internal volume, a photovoltaic cell positioned in the internal volume, and an optical element that includes an optically active body and a flange extending outward from the body, wherein the flange is sealingly engaged with the rim of the housing to enclose the internal volume.

  1. Le contrôle des concentrations

    OpenAIRE

    Laurence Idot

    2002-01-01

    Globalisation is not only characterized by an increasing number of international mergers and acquisitions, but also by a proliferation of national systems of competition law and of control of industrial concentration. The multitude of national systems of control, however similar in their principles, results in a diversity of laws both as regards substance and enforcement. Therefore, rather than compensating for the absence of international rules of competition law, the many national laws incr...

  2. Cadmium blood concentrations in relation to nutrition.

    Science.gov (United States)

    Krajcovicová-Kudládková, Marica; Ursínyová, Monika; Masánová, Vlasta; Béderová, Alzbeta; Valachovicová, Martina

    2006-09-01

    Cadmium is a toxic element ubiquitous in the environment, which damages biological systems in various ways. The major source of cadmium exposure is food. High cadmium content in the soil leads to high cadmium concentrations in certain plants such as grains (above all surface layers and germs), oil or non-oil seeds, fruit and vegetables. These food commodities are the crucial components of a vegetarian nutrition. Blood cadmium concentrations were measured in two non-smoking population groups: the vegetarian group (n = 80) and the non-vegetarian (control) group of general population on traditional mixed diet (n = 84). The significantly higher blood cadmium content (1.78 +/- 0.22 vs. 0.45 +/- 0.04 microg/l) was measured in vegetarian group. Healthy risk values > 5 microg/l were found in 6 vegetarians vs. no non-vegetarian. The highest cadmium concentration (3.15 +/- 0.77 microg/l) was measured in vegan subgroup (plant food only, n = 10) and that value decreased with increasing animal food consumption (1.75 +/- 0.36 microg/l, lactovegetarian and lactoovovegetarian subgroup/added dairy products and eggs, n = 41/, 1.34 +/- 0.21 microg/I, semivegetarian subgroup /as a previous subgroup and added white meat, n = 291). Risk vegetarians vs. non-risk vegetarians consume significantly higher amounts of whole grain products, grain sprouts and oil seeds. Blood cadmium content is directly influenced by age (r = 0.32, p vegetarianism (r = 0.5, p Vegetarians have significantly higher plasma concentrations of natural antioxidants. The sufficient antioxidative protection against cadmium induced free radical formation in vegetarians may inhibit the harmful effects of greater cadmium intake from plant food. PMID:17152224

  3. Determinants of Manufacturing Concentration Patterns in Mercosur

    OpenAIRE

    Traistaru, Iulia; Martincus, Christian Volpe

    2003-01-01

    Over the last fifteen years, Argentina, Brazil, Paraguay and Uruguay have implemented major economic reforms including unilateral trade liberalization programs and the constitution of a regional trade bloc, Mercosur. This trade policy change has led to a reallocation of resources across sectors and space. The impact of the trade liberalization on industrial production structures in Mercosur countries has been little investigated so far. How concentrated /dispersed are manufacturing activities...

  4. Managerial incentives, financial constraints and ownership concentration

    OpenAIRE

    Marco Protopapa

    2011-01-01

    This work investigates the role of equity ownership for the purpose of committing the management to the pursuit of shareholder value in the presence of separation between ownership and control. By rooting the conflicts of interests between managers and shareholders upon the control of internal funds, a simple model allows to analyse the link between profit uncertainty, growth options and decisional powers. Implications are derived for the optimal degree of equity concentration, the effect of ...

  5. Optimal control of sun tracking solar concentrators

    Science.gov (United States)

    Hughes, R. O.

    1979-01-01

    Application of the modern control theory to derive an optimal sun tracking control for a point focusing solar concentrator is presented. A standard tracking problem converted to regulator problem using a sun rate input achieves an almost zero steady state tracking error with the optimal control formulation. However, these control techniques are costly because optimal type algorithms require large computing systems, thus they will be used mainly as comparison standards for other types of control algorithms and help in their development.

  6. Concentration of lemon pectin extract by ultrafiltration

    OpenAIRE

    Damián Stechina; Miguel Pauletti; Claudia Lesa; Rodolfo Hugo Maffioly; Nicolas Bogdanoff; Oscar Iribarren

    2012-01-01

    Current annual lemon production in Argentina is about 900 thousand t. 75% is used industrially to obtain pasteurized juice concentrate. Since 40 - 45 % of citrus fruit content is peel and seeds, the annual lemon residue yield is 360 thousand t. Lemon peel contains about 30% (B.S.) of peptic substances with an important commercial value due to its gelling and thickening properties for food, chemical, pharmacological and cosmetic products. Membrane processes have many applications in food manuf...

  7. Smart badge for monitoring formaldehyde exposure concentration

    OpenAIRE

    Fathallah, Houssem,; Lecuire, Vincent; Rondeau, Eric; Le Calvé, Stéphane

    2015-01-01

    Formaldehyde is used by many industrial processes (e.g., paper, wood, textile). The World Health Organization classifies formaldehyde in the category 3 of carcinogenic substances and defines exposure limits in professional context. The objective of CAPFEIN project funded by the French National Research Agency is to develop smart systems enabling to estimate formaldehyde exposure concentrations of employers working in closed environment. This research project gathering researchers in chemistry...

  8. Design package for concentrating solar collector panels

    Science.gov (United States)

    1978-01-01

    Information used to evaluate the design of the Northrup concentrating collector is presented. Included are the system performance specifications, the applications manual, and the detailed design drawings of the collector. The collector is a water/glycol/working fluid type, with a dipped galvanized steel housing, transparent acrylic Fresnel lens cover, copper absorber tube, and fiber glass insulation. It weights 98 pounds. A collector assembly includes four collector units within a tracking mount array.

  9. Sunflower meal concentrations in Massai grass silage

    OpenAIRE

    Máikal S. Borja; Oliveira, Ronaldo L.; Luciano S. Lima; Adriana R. Bagaldo; Gleidson GP. Carvalho; Cláudio VDM Ribeiro

    2015-01-01

    ABSTRACTObjetive. This experiment was conducted to evaluate the best sunflower meal concentration in Massai grass silage. Materials and methods. The treatments were composed of 0, 8, 16, and 24% sunflower meal (natural matter basis) during ensiling of Massai grass, with four repetitions. Results. The regression equation showed that the inclusion of sunflower meal between 2.14% and 13.91% obtained a silage dry matter between 25 and 35%, which are the values recommended for the production of hi...

  10. RHEOLOGY OF CHICKPEA PROTEIN CONCENTRATE DISPERSIONS

    OpenAIRE

    Aurelia Ionescu; Iuliana Aprodu; Gabriela Gurau; Iuliana Banu

    2011-01-01

    Chickpea proteins are used as ingredients in comminuted sausage products and many oriental textured foods. Rheological behaviour of chickpea protein concentrate was studied using a controlled stress rheometer. The protein dispersion prepared with phosphate buffer at pH 7.0 presented non-Newtonian shear thinning behaviour and rheological data well fitted to the Sisko, Carreau and Cross models. The viscoelastic properties of the chickpea protein suspensions were estimated by measuring the stora...

  11. Distance Concentration-Based Artificial Immune Algorithm

    Institute of Scientific and Technical Information of China (English)

    LIU Tao; WANG Yao-cai; WANG Zhi-jie; MENG Jiang

    2005-01-01

    The diversity, adaptation and memory of biological immune system attract much attention of researchers. Several optimal algorithms based on immune system have also been proposed up to now. The distance concentration-based artificial immune algorithm (DCAIA) is proposed to overcome defects of the classical artificial immune algorithm (CAIA) in this paper. Compared with genetic algorithm (GA) and CAIA, DCAIA is good for solving the problem of precocity,holding the diversity of antibody, and enhancing convergence rate.

  12. Decomposition of s-Concentration Curves

    OpenAIRE

    Makdissi, Paul; Mussard, Stéphane

    2006-01-01

    For any given order of inverse stochastic dominance, standard concentration curves are decomposed into three components, called contribution curves. Those components correspond to within-group inequalities, between-group inequalities, and transvariational inequalities. We prove, for all orders, that contribution curve dominance implies systematically welfare-improving tax reforms and conversely. Accordingly, as welfare expansions may be costly in terms of particular inequalities, we propose t...

  13. Magnetization of concentrated polydisperse ferrofluids: Cluster expansion

    OpenAIRE

    Huke, B.; Luecke, M.

    2006-01-01

    The equilibrium magnetization of concentrated ferrofluids described by a system of polydisperse dipolar hard spheres is calculated as a function of the internal magnetic field using the Born--Mayer or cluster expansion technique. This paper extends the results of Phys. Rev. E 62, 6875 (2000) obtained for monodisperse ferrofluids. The magnetization is given as a power series expansion in two parameters related to the volume fraction and the coupling strength of the dipolar interaction, respect...

  14. Specific dietary patterns and concentrations of adiponectin

    OpenAIRE

    Vajihe Izadi; Leila Azadbakht

    2015-01-01

    Background: One of the adipokines mostly secreted from adipose tissue is adiponectin. Adiponectin is well known as the anti-diabetic, anti-obesity and cardio-protective factor. Present study focused on the review the previous studies about relationship between adherence to healthy dietary pattern, independent of one or two special dietary components, and concentration of adiponectin. Materials and Methods: We searched in PubMed search engine from 2003 to July 2014 using the following key word...

  15. The sharp quantitative Euclidean concentration inequality

    OpenAIRE

    Figalli, Alessio; Maggi, Francesco; Mooney, Connor

    2016-01-01

    The Euclidean concentration inequality states that, among sets with fixed volume, balls have $r$-neighborhoods of minimal volume for every $r>0$. On an arbitrary set, the deviation of this volume growth from that of a ball is shown to control the square of the volume of the symmetric difference between the set and a ball. This estimate is sharp and includes, as a special case, the sharp quantitative isoperimetric inequality proved in \\cite{fuscomaggipratelli}.

  16. A Review of Solar Photovoltaic Concentrators

    OpenAIRE

    Mehrdad Khamooshi; Hana Salati; Fuat Egelioglu; Ali Hooshyar Faghiri; Judy Tarabishi; Saeed Babadi

    2014-01-01

    Throughout the recent centuries, the limits of using energy resources due to the cost and environmental issues became one of the scientists’ concerns. Because of the huge amount of energy received by the Earth from the sun, the application of photovoltaic solar cells has become popular in the world. The photovoltaic (PV) efficiency can be increased by several factors; concentrating photovoltaic (CPV) system is one of the important tools for efficiency improvement and enables for a reduction i...

  17. Quantized Concentration Gradient in Picoliter Scale

    Science.gov (United States)

    Hong, Jong Wook

    2010-10-01

    Generation of concentration gradient is of paramount importance in the success of reactions for cell biology, molecular biology, biochemistry, drug-discovery, chemotaxis, cell culture, biomaterials synthesis, and tissue engineering. In conventional method of conducting reactions, the concentration gradients is achieved by using pipettes, test tubes, 96-well assay plates, and robotic systems. Conventional methods require milliliter or microliter volumes of samples for typical experiments with multiple and sequential reactions. It is a challenge to carry out experiments with precious samples that have strict limitations with the amount of samples or the price to pay for the amount. In order to overcome this challenge faced by the conventional methods, fluidic devices with micrometer scale channels have been developed. These devices, however, cause restrictions on changing the concentration due to the fixed gradient set based on fixed fluidic channels.ootnotetextJambovane, S.; Duin, E. C.; Kim, S-K.; Hong, J. W., Determination of Kinetic Parameters, KM and kcat, with a Single Experiment on a Chip. textitAnalytical Chemistry, 81, (9), 3239-3245, 2009.^,ootnotetextJambovane, S.; Hong, J. W., Lorenz-like Chatotic System on a Chip In The 14th International Conference on Miniaturized Systems for Chemistry and Life Sciences (MicroTAS), The Netherlands, October, 2010. Here, we present a unique microfluidic system that can generate quantized concentration gradient by using series of droplets generated by a mechanical valve based injection method.ootnotetextJambovane, S.; Rho, H.; Hong, J., Fluidic Circuit based Predictive Model of Microdroplet Generation through Mechanical Cutting. In ASME International Mechanical Engineering Congress & Exposition, Lake Buena Vista, Florida, USA, October, 2009.^,ootnotetextLee, W.; Jambovane, S.; Kim, D.; Hong, J., Predictive Model on Micro Droplet Generation through Mechanical Cutting. Microfluidics and Nanofluidics, 7, (3), 431-438, 2009

  18. Temperature-concentration diagram of polymer solutions

    International Nuclear Information System (INIS)

    A (T,C) diagram - were T is the temperature, C the monomer concentration - is described for polymer solutions, from a tricritical approach to the polymer theta point. Four different regions are defined in this diagram. For each of these regions the T, N, C, dependence of the mean square end to end distance of a chain, the screening length, the osmotic pressure, and the second virial coefficient are calculated. A scaling form is also given for the equation of state

  19. A Wall of Funnels Concentrates Swimming Bacteria▿

    OpenAIRE

    Galajda, Peter; Keymer, Juan; Chaikin, Paul; Austin, Robert

    2007-01-01

    Randomly moving but self-propelled agents, such as Escherichia coli bacteria, are expected to fill a volume homogeneously. However, we show that when a population of bacteria is exposed to a microfabricated wall of funnel-shaped openings, the random motion of bacteria through the openings is rectified by tracking (trapping) of the swimming bacteria along the funnel wall. This leads to a buildup of the concentration of swimming cells on the narrow opening side of the funnel wall but no concent...

  20. Normal and Pathologic Concentrations of Uremic Toxins

    OpenAIRE

    Duranton, Flore; Cohen, Gerald; De Smet, Rita; Rodriguez, Mariano; Jankowski, Joachim; Vanholder, Raymond; Argiles, Angel

    2012-01-01

    An updated review of the existing knowledge regarding uremic toxins facilitates the design of experimental studies. We performed a literature search and found 621 articles about uremic toxicity published after a 2003 review of this topic. Eighty-seven records provided serum or blood measurements of one or more solutes in patients with CKD. These records described 32 previously known uremic toxins and 56 newly reported solutes. The articles most frequently reported concentrations of β2-microgl...

  1. Serum ferritin concentration in sickle cell crisis.

    OpenAIRE

    Brownell, A; Lowson, S; Brozović, M

    1986-01-01

    Serum ferritin, aspartate aminotransferase (AST), alkaline phosphatase and hydroxybutyrate dehydrogenase (HBD) were studied during 21 vaso-occlusive crises in 12 adults with sickle cell disease (11 SS, 1 S beta degrees). The patients comprised three groups: those who had been untransfused (4), those who had received occasional exchange transfusion in crisis (3), and those who had been multiply transfused (5). Serum ferritin concentrations in crisis were compared with those of the steady state...

  2. Degadation of semiconducting polymers by concentrated sunlight

    DEFF Research Database (Denmark)

    Tromholt, Thomas; Manceau, Matthieu; Petersen, Martin Helgesen;

    2011-01-01

    A lens based sunlight concentration setup was used to accelerate the degradation of semiconducting polymers. Sunlight was collected outdoor and focused into an optical fiber bundle allowing for indoor experimental work. Photo-degradation of several polymers was studied by UV–vis absorbance...... was carried out in a materials study employing five different conjugated polymers relevant to polymer solar cells for which acceleration factors in the range 19–55 were obtained....

  3. Arsenic concentrations in groundwaters of Cyprus

    Science.gov (United States)

    Christodoulidou, M.; Charalambous, C.; Aletrari, M.; Nicolaidou Kanari, P.; Petronda, A.; Ward, N. I.

    2012-10-01

    SummaryCyprus being a Mediterranean island with long dry summers and mild winters suffers from water deficiency and over exploitation of its water resources. Groundwater in Cyprus is a valuable natural resource as approximately 50% of the total water needs come from underground water supplies. According to the Directive 118/2006/EC, groundwater should be protected from deterioration and chemical pollution, this is particularly important for groundwater dependent ecosystems and for the use of groundwater as a water supply for human consumption. During 2007 to 2009, as part of a national monitoring programme, 84 boreholes were sampled in Cyprus and subsequently analysed for total arsenic by inductively coupled plasma mass spectrometry (ICP-MS). The groundwater concentrations ranged from <0.3 to 41 μg/L As. Several boreholes located in a rural farming district near Nicosia had concentrations above the World Health Organisation (WHO) Drinking Water Guideline limit of 10 μg/L As. Evaluation of the groundwater sampling procedure for boreholes provided data recommending that water samples should be collected after an initial borehole washout for 5 min. Further sampling of these boreholes in 2010, revealed total arsenic concentrations of <0.3-64.2 μg/L As, with the predominant arsenic species (determined using a novel field-based methodology) being arsenate (AsV). The maximum total arsenic concentration is 6-fold higher than the WHO Drinking Water Guideline limit (10 μg/L As) and approximately half of the United Nations Food and Agriculture Organisation (UN-FAO) irrigational limit of 100 μg/L As.

  4. Measurement of Odour Concentration from Livestock Farm

    OpenAIRE

    Lukman Ismail; Zaini Sakawi; Mohamad Khalil Saipi

    2014-01-01

    Odourpollution originated from livestock farms is a form of harmful air pollution.Odour pollution causes health issues to the surrounding local communities. Yet, odour pollution issues have not been given deserving attention by the relevant authorities and the Malaysian public. To raise the awareness, this study highlights a case of odour pollution generated from cattle and buffalo farms in Bandar Baru Bangi, Selangor.Odour measurement was taken using an instrument called Concentration Meter ...

  5. Technological Concentration of Innovation in Agribusiness

    OpenAIRE

    Alfranca, Oscar

    2005-01-01

    The main objective of the paper is to examine and discuss the nature of technological relationships across agrifood sectors in order to understand better the pattern of technological changes in the Food and Beverage sector. We propose a new estimator to confirm the existence of linkages between technological sectors (the Technological Concentration Index). A central conclusion from this work is that the quality of data is a principal determinant in the measurement of technological flows, and ...

  6. Palatability of concentrates fed to sheep

    OpenAIRE

    Mereu, Alessandro

    2009-01-01

    Palatability of concentrates is important to avoid feed refusal and production losses in ruminants. Thus, the palatability of 14 feeds (soybean meal 44 and 49; soybean hulls; corn grains; canola meal; wheat grains; beet pulps; dehydrated alfalfa; sunflower meal; oat grains; pea grains; wheat brans; corn middlings; corn gluten meal) was measured in 6 min daily tests on 14 female lambs and 14 dry multiparous ewes. The palatability of the feeds fed to the lambs varied from high to...

  7. Pricing and Market Concentration in Oligopoly Markets

    OpenAIRE

    Vishal Singh; Ting Zhu

    2008-01-01

    This paper investigates the relationship between prices and market concentration in the auto rental industry. We assemble an original database that includes the number of auto rental operators and other exogenous demand and cost conditions at every commercial airport in the country. The data are interesting because we observe a large variation in market structure, ranging from more than 100 monopoly and duopoly markets to several competitive airports with more than eight firms. In addition, w...

  8. Auditing, Consulting, and Audit Market Concentration

    OpenAIRE

    Christopher Bleibtreu; Ulrike Stefani

    2011-01-01

    In its recently published Green Paper, the European Commission 2010 discusses various methods to enhance the reliability of audits and to re-establish trust in the financial market. The Commission primarily focuses on increasing auditor independence and on reducing the high level of audit market concentration. Based on a model in the tradition of the circular market matching models introduced by Salop 1979, we show that prohibiting non-audit services as a measure intended to improve auditor i...

  9. Cylinder light concentrator and absorber: theoretical description

    OpenAIRE

    Kildishev, Alexander V.; Prokopeva, Ludmila J.; Narimanov, Evgenii

    2010-01-01

    We present a detailed theoretical description of a broadband omnidirectional light concentrator and absorber with cylinder geometry. The proposed optical "trap" captures nearly all the incident light within its geometric cross-section, leading to a broad range of possible applications from solar energy harvesting to thermal light emitters and optoelectronic components. We have demonstrated that an approximate lamellar black-hole with a moderate number of homogeneous layers, while giving the d...

  10. Zirconium oxide obtainment from brazilian zircon concentrate

    International Nuclear Information System (INIS)

    This work presents the experimental results of studies about alkaline melting, acid leaching and sulfation steps for obtention of zirconium oxide and partially stabilized zirconia by yttrium and rare-earth coprecipitation in chlorine medium, starting from the brazilian zircon concentrate. Using statistical methods of factorial design and the Packett-Burman approach, the results are discussed and the optimal conditions of the production steps were determined. (author)

  11. Concentration Yield of Biopetrol from Oleic Acid

    Directory of Open Access Journals (Sweden)

    S.N. Hassan

    2009-01-01

    Full Text Available Biopetrol is defined as fuel which has the same characteristics with commercial petrol in terms of its molecular formula. The current petrol disaster and the valuable oleic acid loss by disposal to environment are the problematic reasons that the biopetrol should be synthesized from oleic acid. The objective of this study is to find the concentration of biopetrol (dominated by isooctane from oleic acid in palm oil waste. Catalytic cracking process is used to synthesize isooctane from oleic acid, using zeolite as catalyst. Oleic acid is naturally in liquid form, so oleic acid is directly heated until achieving isooctane’s boiling point of 98°C to form new arrangements of carbon compounds including isooctane. Various masses of catalyst are used, which are 1, 5, 10 and 20 g. After the cracking process is completed, the samples from oleic acid’s distillates were collected. The desired isooctane obtained is around 0.04-2.15% in the distilled oleic acid, with the presence of hexane as dilution solvent. After applying back calculation to obtain actual isooctane concentrations in both distillates with comparison to the pure isooctane, the highest concentration of the desired isooctane in oleic acid distillate is 7.886% for 20 g zeolite.

  12. White butterflies as solar photovoltaic concentrators

    Science.gov (United States)

    Shanks, Katie; Senthilarasu, S.; Ffrench-Constant, Richard H.; Mallick, Tapas K.

    2015-07-01

    Man’s harvesting of photovoltaic energy requires the deployment of extensive arrays of solar panels. To improve both the gathering of thermal and photovoltaic energy from the sun we have examined the concept of biomimicry in white butterflies of the family Pieridae. We tested the hypothesis that the V-shaped posture of basking white butterflies mimics the V-trough concentrator which is designed to increase solar input to photovoltaic cells. These solar concentrators improve harvesting efficiency but are both heavy and bulky, severely limiting their deployment. Here, we show that the attachment of butterfly wings to a solar cell increases its output power by 42.3%, proving that the wings are indeed highly reflective. Importantly, and relative to current concentrators, the wings improve the power to weight ratio of the overall structure 17-fold, vastly expanding their potential application. Moreover, a single mono-layer of scale cells removed from the butterflies’ wings maintained this high reflectivity showing that a single layer of scale cell-like structures can also form a useful coating. As predicted, the wings increased the temperature of the butterflies’ thorax dramatically, showing that the V-shaped basking posture of white butterflies has indeed evolved to increase the temperature of their flight muscles prior to take-off.

  13. On the application of concentration factor

    International Nuclear Information System (INIS)

    Concentration factor is used to estimate internal dose through consumption of fish and shellfish. The amount of nuclide intake is estimated as ''radioactivity in ambient water x concentration factor x consumption of fish and shellfish''. These parameters involved are usually treated as constants but these actually are variables. Here the significance of their variation on dose assessment is examined. Concentration factors are varied according to various environmental as well as biological factors. For example, Hg, Cs, and As in the muscle of Galeus nipponensis increase as total length increases and, on the contrary, Cu, Zn, Fe and Co show negative correlation with total length. We should examine these cases and determine what value should be used in dose assessment. More important is to build up models to interprete these phenomena totally. Significance of variation in ambient radioactivity was examined by a simulation of nuclide accumulation in biota exposed to intermittent release and compared with that to continuous release. Variations either within a day or within a year were not shown to have much effect. On the variations in sea food consumption, several examples were given. Problem to be solved is how to consider these variations on assessing internal dose due to fish consumption. In conclusion it is necessary to get more of such kind of informations on the variations of parameters. And also we should determine the precision of each parameter in the whole picture of dose assessment. (author)

  14. Industrial solar breeder project using concentrator photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, R; Wohlgemuth, J; Burkholder, J; Levine, A; Storti, G; Wrigley, C; McKegg, A

    1979-08-01

    The purpose of this program is to demonstrate the use of a concentrating photovoltaic system to provide the energy for operating a silicon solar cell production facility, i.e., to demonstrate a solar breeder. Solarex has proposed to conduct the first real test of the solar breeder concept by building and operating a 200 kW(e) (peak) concentrating photovoltaic system based on the prototype and system design developed during Phase I. This system will provide all of the electrical and thermal energy required to operate a solar cell production line. This demonstration would be conducted at the Solarex Rockville facility, with the photovoltaic array located over the company parking lot and on an otherwise unusable flood plain. Phase I of this program included a comprehensive analysis of the application, prototype fabrication and evaluation, system design and specification, and a detailed plan for Phases II and III. A number of prototype tracking concentrator solar collectors were constructed and operated. Extensive system analysis was performed to design the Phase II system as a stand-alone power supply for a solar cell production line. Finally, a detailed system fabrication proposal for Phase II and an operation and evaluation plan for Phase III were completed. These proposals included technical, management, and cost plans for the fabrication and exercise of the proposed system.

  15. Seasonal indoor radon concentration in Eskisehir, Turkey

    International Nuclear Information System (INIS)

    Indoor radon concentrations are subject to seasonal variation, which directly depends on weather conditions. The seasonal indoor radon concentrations were measured and the annual effective dose was estimated for the city centre of Eskisehir, Turkey. In order to reflect annual averages measurements were performed over all seasons (winter, spring, summer and autumn) including also the entire year. Measurements were carried out using Kodak-Pathe LR 115 Type II passive alpha track detectors in 220 different houses. A total of 534 measurements including measurements of different seasons were taken between 2010 and 2011. The radon concentrations for winter ranged from 34 to 531 Bq m-3, for spring ranged from 22 to 424 Bq m-3 , for summer ranged from 25 to 320 Bq m-3, and for autumn ranged from 19 to 412 Bq m-3. Yearly measurements ranged from 19 to 338 Bq m-3. In this study the average annual effective total dose from radon and its decay products was calculated to be 3.398 mSv y-1. (authors)

  16. Methods for macro concentration speciation (>106 M)

    International Nuclear Information System (INIS)

    The range of topics covered by the term 'speciation' varies from the determination of isotopic composition, through whether an element or nuclide is present and under which form, to the full identification of the molecular compound present or the isolation of species. Therefore, it is quite understandable that a rather large range of techniques may be applicable for speciation purposes and that none may be sufficient by itself to cover all purposes. We tried in this report to review on technologies available for speciation purposes in nuclear fuel cycle activities and to provide a reference document to guide researchers in choosing the most useful technique for his purposes by summarizing their characteristics. Particular attention was given to highlight the advantages and disadvantages/limitations of a given technique as well as, when suitable, expected or necessary future improvements. It was also attempted to indicate a 'recommended' application field, though this was not an easy task. In the present part, we concentrate on techniques available for macro concentration speciation with an arbitrary limit fixed around 10-6 M. However, one should be aware that some of the techniques discussed in the present may be also applicable for lower concentration (overlap with over Partim. of the whole report) and vice-versa. Then, we consider that the scope of the present can only be achieved considering the whole parts discussed at the OECD/NEA Workshop on evaluation of speciation technology held in October 1999 at JAERI/Tokai-mura. (author)

  17. Passive CO2 concentration in higher plants.

    Science.gov (United States)

    Sage, Rowan F; Khoshravesh, Roxana

    2016-06-01

    Photorespiratory limitations on C3 photosynthesis are substantial in warm, low CO2 conditions. To compensate, certain plants evolved mechanisms to actively concentrate CO2 around Rubisco using ATP-supported CO2 pumps such as C4 photosynthesis. Plants can also passively accumulate CO2 without additional ATP expenditure by localizing the release of photorespired and respired CO2 around Rubisco that is diffusively isolated from peripheral air spaces. Passive accumulation of photorespired CO2 occurs when glycine decarboxylase is localized to vascular sheath cells in what is termed C2 photosynthesis, and through forming sheaths of chloroplasts around the periphery of mesophyll cells. The peripheral sheaths require photorespired CO2 to re-enter chloroplasts where it can be refixed. Passive accumulation of respiratory CO2 is common in organs such as stems, fruits and flowers, due to abundant heterotrophic tissues and high diffusive resistance along the organ periphery. Chloroplasts within these organs are able to exploit this high CO2 to reduce photorespiration. CO2 concentration can also be enhanced passively by channeling respired CO2 from roots and rhizomes into photosynthetic cells of stems and leaves via lacunae, aerenchyma and the xylem stream. Through passive CO2 concentration, C3 species likely improved their carbon economy and maintained fitness during episodes of low atmospheric CO2. PMID:27058940

  18. Microfluidic distillation chip for methanol concentration detection.

    Science.gov (United States)

    Wang, Yao-Nan; Liu, Chan-Chiung; Yang, Ruey-Jen; Ju, Wei-Jhong; Fu, Lung-Ming

    2016-03-17

    An integrated microfluidic distillation system is proposed for separating a mixed ethanol-methanol-water solution into its constituent components. The microfluidic chip is fabricated using a CO2 laser system and comprises a serpentine channel, a boiling zone, a heating zone, and a cooled collection chamber filled with de-ionized (DI) water. In the proposed device, the ethanol-methanol-water solution is injected into the microfluidic chip and driven through the serpentine channel and into the collection chamber by means of a nitrogen carrier gas. Following the distillation process, the ethanol-methanol vapor flows into the collection chamber and condenses into the DI water. The resulting solution is removed from the collection tank and reacted with a mixed indicator. Finally, the methanol concentration is inversely derived from the absorbance measurements obtained using a spectrophotometer. The experimental results show the proposed microfluidic system achieves an average methanol distillation efficiency of 97%. The practicality of the proposed device is demonstrated by detecting the methanol concentrations of two commercial fruit wines. It is shown that the measured concentration values deviate by no more than 3% from those obtained using a conventional bench top system. PMID:26920777

  19. Determining concentration inhomogeneity inside liquid holding tanks

    International Nuclear Information System (INIS)

    Incorporating concentration measurements of special nuclear material (SNM) in a chemical processing accountability program requires uncertainty data for three types of errors: mixing, sampling, and analytical. Usually, the analytical measurement uncertainties - both random and systematic - are routinely determined for the laboratory instruments and procedures being used to measure the concentration of withdrawn liquid samples. However, little data currently exists to determine how representative the withdrawn liquid sample is in relation to the true average bulk concentration within the tank itself. This sample representativeness depends upon uncertainties associated with the tank mixing and sampling procedures. Both types of uncertainties are investigated. Mixing uncertainty or inhomogeneity has been found to be primarily a fluid mechanics problem while sampling uncertainty involves mostly chemistry. Experimental results are presented along with the early developments of a scaling analysis for future process design and accountability work. Tests were performed on full size pencil, double pencil, and annular tanks using saltwater solutions to achieve various levels of density stratifications within the tanks analogous to nitric acids solutions of different normalities

  20. Insurance risk of nuclear power plant concentrations

    International Nuclear Information System (INIS)

    The limited number of sites available in the Federal Republic of Germany for the erection of nuclear power plants has resulted in the construction of multiple nuclear generating units on a few sites, such as Biblis, Gundremmingen and Neckarwestheim. At a value invested of approximately DM 1,200/kW this corresponds to a property concentration on one site worth DM 2 - 3 billion and more. This raises the question whether a concentration of value of this magnitude does not already exceed the limits of bearable economic risks. The property risk of a nuclear power plant, as that of any other industrial plant, is a function of the property that can be destroyed in a maximum probable loss. Insurance companies subdivide plants into so-called complex areas in which fire damage or nuclear damage could spread. While in some foreign countries twin nuclear power plants are built, where the technical systems of both units are installed in one building without any physical separation, dual unit plants are built in the Federal Republic in which the complexes with a high concentration of valuable property are physically separate building units. As a result of this separation, property insurance companies have no grounds for assessing the risk and hence, the premium different from those of single unit plants. (orig.)

  1. Measurement of Odour Concentration from Livestock Farm

    Directory of Open Access Journals (Sweden)

    Lukman Ismail

    2014-08-01

    Full Text Available Odourpollution originated from livestock farms is a form of harmful air pollution.Odour pollution causes health issues to the surrounding local communities. Yet, odour pollution issues have not been given deserving attention by the relevant authorities and the Malaysian public. To raise the awareness, this study highlights a case of odour pollution generated from cattle and buffalo farms in Bandar Baru Bangi, Selangor.Odour measurement was taken using an instrument called Concentration Meter Xp-369 Series III. Measurement was taken during various weather and times, usually on normal days and after rains. Observationswere conducted at different times inthe mornings, evenings and nights. Ten stations were selected as locations for measuring the odour concentration within two kilometres from the livestock farms. The results indicated that after rain odour concentration gave higher readings compared to those of normal days.This phenomenon was caused by the meteorological factors such as temperature, comparative humidity; and variation in wind speed and directions on normal days and after rains.Enhancement of livestock management is suggested for mitigating the odour pollution.

  2. RHEOLOGY OF CHICKPEA PROTEIN CONCENTRATE DISPERSIONS

    Directory of Open Access Journals (Sweden)

    Aurelia Ionescu

    2011-12-01

    Full Text Available Chickpea proteins are used as ingredients in comminuted sausage products and many oriental textured foods. Rheological behaviour of chickpea protein concentrate was studied using a controlled stress rheometer. The protein dispersion prepared with phosphate buffer at pH 7.0 presented non-Newtonian shear thinning behaviour and rheological data well fitted to the Sisko, Carreau and Cross models. The viscoelastic properties of the chickpea protein suspensions were estimated by measuring the storage and loss moduli in oscillatory frequency conditions (0.1-10 Hz at 20°C. Moreover, thermally induced gelation of the chickpea proteins (16, 24 and 36% was studied at pH 7.0 and 4.5 in the temperature range 50 to 100oC and salt concentration ranging from 0 to 1 M. Gelling behaviour was quantified by means of dynamic rheological measurements. Gels formation was preceded by the decrease of storage modulus and loss moduli, coupled with the increase of the phase angle (delta. The beginning of thermal gelation was influenced by protein concentration, pH and salt level. In all studied cases, storage modulus increased rapidly in the temperature range 70-90°C. All rheological parameters measured at 90°C were significantly higher at pH 4.5 compared to pH 7.0.

  3. Point-focus spectral splitting solar concentrator for multiple cells concentrating photovoltaic system

    International Nuclear Information System (INIS)

    In this paper we present and experimentally validate a low-cost design of a spectral splitting concentrator for the efficient conversion of solar energy. The optical device consists of a dispersive prismatic lens made of polycarbonate designed to simultaneously concentrate solar light and split it into its spectral components. With respect to our previous implementation, this device concentrates light along two axes and generates a light pattern compatible with the dimensions of a set of concentrating photovoltaic cells, while providing a higher concentration ratio. The mathematical framework and the constructive approach used for the design are presented and the device performance is simulated using ray-tracing software. We obtain spectral separation in the visible range within a 3 × 1 cm2 area and a maximum concentration of 210× for a single wavelength. The device is fabricated by injection molding and its performance is experimentally investigated. We measure an optical transmissivity above 90% in the range 400–800 nm and we observe a spectral distribution in good accordance with simulations. Our results demonstrate the feasibility of the device for cost effective high efficiency concentrated photovoltaic systems. (paper)

  4. Point-focus spectral splitting solar concentrator for multiple cells concentrating photovoltaic system

    Science.gov (United States)

    Maragliano, Carlo; Chiesa, Matteo; Stefancich, Marco

    2015-10-01

    In this paper we present and experimentally validate a low-cost design of a spectral splitting concentrator for the efficient conversion of solar energy. The optical device consists of a dispersive prismatic lens made of polycarbonate designed to simultaneously concentrate solar light and split it into its spectral components. With respect to our previous implementation, this device concentrates light along two axes and generates a light pattern compatible with the dimensions of a set of concentrating photovoltaic cells, while providing a higher concentration ratio. The mathematical framework and the constructive approach used for the design are presented and the device performance is simulated using ray-tracing software. We obtain spectral separation in the visible range within a 3 × 1 cm2 area and a maximum concentration of 210× for a single wavelength. The device is fabricated by injection molding and its performance is experimentally investigated. We measure an optical transmissivity above 90% in the range 400-800 nm and we observe a spectral distribution in good accordance with simulations. Our results demonstrate the feasibility of the device for cost effective high efficiency concentrated photovoltaic systems.

  5. Physico-Chemical changes in valencia orange concentrate during commercial scale vacuum concentration

    Directory of Open Access Journals (Sweden)

    J. S. Pruthi

    1959-01-01

    Full Text Available "Changes in the refractometric solids (Brix, viscosity, spectral reflectance (color, pH, acidity, Brix/acid ratio, color, true ascorbic acid and carotene during commercial scale vacuum concentration of Valencia orange juice in a forced circulation, single-pass, falling-film Evaporator have been reported. With the advancing concentration, there was a gradual increase in Brix, acidity, viscosity, color, ascorbic acid and carotene, no change in Brix/acid ratio but a slight fall in pH. Upto 4-fold concentration of the Juice, the increase in viscosity was comparatively slight, but after 5-fold concentration, there was a steep rise in viscosity. There were negligible losses in carotene while the losses in true ascorbic acid were well within 5% during concentration up to 63Degree Brix. Use of mid-season, healthy ripe oranges for juice extraction and concentration of the flash-heated juice (195Degree-200DegreeF for 10-12 seconds upto 5-fold concentration are suggested."

  6. Preovulatory progesterone concentration associates significantly to follicle number and LH concentration but not to pregnancy rate

    DEFF Research Database (Denmark)

    Yding Andersen, Claus; Bungum, Leif; Nyboe Andersen, Anders;

    2011-01-01

    with pregnancy outcome. Progesterone concentration was measured on stimulation day 1 and on the day of HCG administration in 475 patients who underwent IVF/intracytoplasmic sperm injection treatment following ovarian stimulation with gonadotrophin-releasing hormone (GnRH) agonist and recombinant FSH...... with or without rLH administration from day 6 of stimulation. There was no significant association between the late-follicular-phase progesterone concentration and the clinical pregnancy rate. However, progesterone concentration was strongly associated with the number of follicles and retrieved oocytes...

  7. Validity of normalized Rietveld phase concentration estimates

    International Nuclear Information System (INIS)

    Full text: The well known normalization condition introduced by Hill and Howard (1987), Wj=Sj(ZMV)j/ Σi Sj(ZMV)i, is valid only if all Si and (ZMV)i are known. The relationship will provide systematic overestimates of phase concentration if there exists in the sample any unidentified phases or an amorphous content. This limitation can be overcome by adding an internal standard at known concentration as described by Hill and Howard, 1987. Sometimes it is impractical to add an internal standard. It would be advantageous to be able to check the validity of the normalized estimates. A check can be made using an external standard, measured or calculated mass absorption values and knowledge of the relationship between the value of the Rietveld scale factor for the external standard and the diffractometer conditions used. This relationship is described by Pratapa et. al., 1998, as Wk=Sk(ZMV)k μm/.[Ss (ZMV)s μms] Ws, where 'k' is in the sample of interest, 's' is in the external standard and the sample of interest and the external standard are measured under the same diffractometer conditions. The external standard does not have to be a pure phase. The restrictions on the external standard are that the phase on interest contains negligible amorphous content, the structure is known (ZMV) and the mass absorption value of external standard at the wavelength of interest can be measured or estimated accurately. Normalized Rietveld phase concentration estimates can be validated by comparing the normalized values against those produced using a previously well-defined external standard. Copyright (1999) Australian X-ray Analytical Association Inc

  8. Spacecraft Maximum Allowable Concentrations for Airborne Contaminants

    Science.gov (United States)

    James, John T.

    2008-01-01

    The enclosed table lists official spacecraft maximum allowable concentrations (SMACs), which are guideline values set by the NASA/JSC Toxicology Group in cooperation with the National Research Council Committee on Toxicology (NRCCOT). These values should not be used for situations other than human space flight without careful consideration of the criteria used to set each value. The SMACs take into account a number of unique factors such as the effect of space-flight stress on human physiology, the uniform good health of the astronauts, and the absence of pregnant or very young individuals. Documentation of the values is given in a 5 volume series of books entitled "Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants" published by the National Academy Press, Washington, D.C. These books can be viewed electronically at http://books.nap.edu/openbook.php?record_id=9786&page=3. Short-term (1 and 24 hour) SMACs are set to manage accidental releases aboard a spacecraft and permit risk of minor, reversible effects such as mild mucosal irritation. In contrast, the long-term SMACs are set to fully protect healthy crewmembers from adverse effects resulting from continuous exposure to specific air pollutants for up to 1000 days. Crewmembers with allergies or unusual sensitivity to trace pollutants may not be afforded complete protection, even when long-term SMACs are not exceeded. Crewmember exposures involve a mixture of contaminants, each at a specific concentration (C(sub n)). These contaminants could interact to elicit symptoms of toxicity even though individual contaminants do not exceed their respective SMACs. The air quality is considered acceptable when the toxicity index (T(sub grp)) for each toxicological group of compounds is less than 1, where T(sub grp), is calculated as follows: T(sub grp) = C(sub 1)/SMAC(sub 1) + C(sub 2/SMAC(sub 2) + ...+C(sub n)/SMAC(sub n).

  9. Fluorescence lifetime to image epidermal ionic concentrations

    Science.gov (United States)

    Behne, Martin J.; Barry, Nicholas P.; Moll, Ingrid; Gratton, Enrico; Mauro, Theodora M.

    2004-09-01

    Measurements of ionic concentrations in skin have traditionally been performed with an array of methods which either did not reveal detailed localization information, or only provided qualitative, not quantitative information. FLIM combines a number of advantages into a method ideally suited to visualize concentrations of ions such as H+ in intact, unperturbed epidermis and stratum corneum (SC). Fluorescence lifetime is dye concentration-independent, the method requires only low light intensities and is therefore not prone to photobleaching or phototoxic artifacts, and because multiphoton lasers of IR wavelength are used, light penetrates deep into intact tissue. The standard method to measure SC pH is the flat pH electrode, which provides reliable information only about surface pH changes, without further vertical or subcellular spatial resolution; i.e., specific microdomains such as the corneocyte interstices are not resolved, and the deeper SC is inaccessible without resorting to inherently disruptive stripping methods. Furthermore, the concept of a gradient of pH through the SC stems from such stripping experiments, but other confirmation for this concept is lacking. Our investigations into the SC pH distribution so far have revealed the crucial role of the Sodium/Hydrogen Antiporter NHE1 in generation of SC acidity, the colocalization of enzymatic lipid processing activity in the SC with acidic domains of the SC, and the timing and localization of emerging acidity in the SC of newborns. Together, these results have led to an improved understanding of the SC pH, its distribution, origin, and regulation. Future uses for this method include measurements of other ions important for epidermal processes, such as Ca2+, and a quantitative approach to topical drug penetration.

  10. Chemical reactions driven by concentrated solar energy

    Science.gov (United States)

    Levy, Moshe

    Solar energy can be used for driving endothermic reactions, either photochemically or thermally. The fraction of the solar spectrum that can be photochemically active is quite small. Therefore, it is desirable to be able to combine photochemical and thermal processes in order to increase the overall efficiency. Two thermally driven reactions are being studied: oil shale gasification and methane reforming. In both cases, the major part of the work was done in opaque metal reactors where photochemical reactions cannot take place. We then proceeded working in transparent quartz reactors. The results are preliminary, but they seem to indicate that there may be some photochemical enhancement. The experimental solar facilities used for this work include the 30 kW Schaeffer Solar Furnace and the 3 MW Solar Central Receiver in operation at the Weizmann Institute. The furnace consists of a 96 sq. m flat heliostat, that follows the sun by computer control. It reflects the solar radiation onto a spherical concentrator, 7.3 m in diameter, with a rim angle of 65 degrees. The furnace was characterized by radiometric and calorimetric measurements to show a solar concentration ratio of over 10,000 suns. The central receiver consists of 64 concave heliostats, 54 sq. m each, arranged in a north field and facing a 52 m high tower. The tower has five target levels that can be used simultaneously. The experiments with the shale gasification were carried out at the lowest level, 20 m above ground, which has the lowest solar efficiency and is assigned for low power experiments. We used secondary concentrators to boost the solar flux.

  11. Analysis and Countermeasures on EquityConcentration

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    This paper starts from the concept and distribution of Tunneling. The main reason of Tunneling is the concentration of Equity andthe incompletion of legal protection for small and medium-sized investors. Tunneling not only infringes small and medium-sizedshareholders' interest, but also violates company's benefit, and further damages the interest of creditors. Tunneling proceeds invariety of ways, one of them is Related Party Transaction, which severely erodes company's benefit. The suggestedcountermeasure for Tunneling is adjusting the property structure, completing the legislation and improving the independentdirector system.

  12. Solar thermal and concentrated solar power barometer

    International Nuclear Information System (INIS)

    After 2 years of sharp decline, the European solar thermal market is bottoming out. The EurObservev'ER survey findings are that the installation figure fell just 1.9% in comparison with 2010, giving a newly-installed collector area of 3.7 million m2. The concentrated solar power sector has been forging ahead alongside the heat production applications, and at the end of 2011 installed capacity passed the one gigawatt mark in Spain for the first time with 1157.2 MWe. (author)

  13. Learning Boolean functions with concentrated spectra

    Science.gov (United States)

    Mixon, Dustin G.; Peterson, Jesse

    2015-08-01

    This paper discusses the theory and application of learning Boolean functions that are concentrated in the Fourier domain. We first estimate the VC dimension of this function class in order to establish a small sample complexity of learning in this case. Next, we propose a computationally efficient method of empirical risk minimization, and we apply this method to the MNIST database of handwritten digits. These results demonstrate the effectiveness of our model for modern classification tasks. We conclude with a list of open problems for future investigation.

  14. Increased plasma fibronectin concentrations in obesity

    DEFF Research Database (Denmark)

    Andersen, T; Dejgaard, A; Astrup, A; Gluud, C

    1987-01-01

    In 23 morbidly obese patients we investigated the influence of a large weight loss (30.6 kg, range 17.5-90.8) on the plasma fibronectin concentrations. Further, changes in plasma fibronectin were related to serum insulin levels and to liver biochemistry. Between the measurements patients had been...... with the degree of hepatic fatty change, declined (p less than 0.01), but the individual change was unrelated with the change in plasma fibronectin. In conclusion, the elevated plasma fibronectin levels in morbidly obese subjects seem to normalize during weight loss. We suggest the normalization to be...

  15. Measuring concentrations of elements using neutron radiation

    International Nuclear Information System (INIS)

    An apparatus for measuring the concentrations of elements in a material by the capture gamma method is claimed. The apparatus comprises either an isotope source or a neutron generator as the neutron source, a semi-conductor detector as the gamma-radiation detector, and a moderator which is, at least in part, heavy water. The detector is adapted to be placed adjacent to or inside a specimen in the flux of slow neutrons so that sufficient moderator is disposed between the source and the sample-detector combination that only relatively few fast neutrons will reach the detector

  16. Natural radioactivity concentrations in building materials

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Kazuo [Building Materials Research Inst., Tokyo (Japan); Asano, Kenji

    1998-01-01

    As part of our study program on environmental radiation levels is buildings, we have undertaken to measure the natural radioactivity, such as radium-226, thorium-232, and potassium-40 in various inorganic building materials. The specimens of their materials include cements, aggregates, concretes, asbestos cement slates, tiles, gypsum boards, rock wool boards, bricks, wall clays, soils, phosphorous ore, zirconia, zircon flower and zircon sand that used in Japan. The ranges and mean values of natural radioactivity concentrations existing in their materials are tabulated and evaluated. (author)

  17. Ownership Concentration, Monitoring and Optimal Board Structure

    OpenAIRE

    Graziano, Clara; Luporini, Annalisa

    2005-01-01

    The paper analyzes the optimal structure of board of directors in a firm with ownership concentrated in the hands of a large shareholder who sits on the board. We focus our attention on the choice between one-tier board who performs all tasks and two-tier board where the management board is in charge of project selection and the supervisory board is in charge of monitoring. We consider the case in which the large shareholder sits on (and controls) the supervisory board but not the management ...

  18. Concentration Distribution in a Mixing Ventilated Room

    DEFF Research Database (Denmark)

    Jensen, Rasmus Lund; Pedersen, D. N.; Nielsen, Peter Vilhelm;

    2001-01-01

    that the air is fully mixed. The objective of this work is to determine the influence of the location of a pollutant, temperature differences and whether the room is furnished or not. It is also investigated if it is sufficient to determine the mean concentration in the room to determine the personal......Today there is an increasing focus on the importance of a proper ventilation system to obtain good working conditions in the term of air and thermal quality to ensure high productivity. Different ventilation principles are used, e.g., mixing ventilation and displacement ventilation. In order to...

  19. Concentration compactness for critical wave maps

    CERN Document Server

    Krieger, Joachim

    2009-01-01

    By means of the concentrated compactness method of Bahouri-Gerard and Kenig-Merle, we prove global existence and regularity for wave maps with smooth data and large energy from 2+1 dimensions into the hyperbolic plane. The argument yields an apriori bound of the Coulomb gauged derivative components of our wave map relative to a suitable norm (which holds the solution) in terms of the energy alone. As a by-product of our argument, we obtain a phase-space decomposition of the gauged derivative components analogous to the one of Bahouri-Gerard.

  20. Suspension Hydrogen Reduction of Iron Oxide Concentrates

    Energy Technology Data Exchange (ETDEWEB)

    H.Y. Sohn

    2008-03-31

    The objective of the project is to develop a new ironmaking technology based on hydrogen and fine iron oxide concentrates in a suspension reduction process. The ultimate objective of the new technology is to replace the blast furnace and to drastically reduce CO2 emissions in the steel industry. The goals of this phase of development are; the performance of detailed material and energy balances, thermochemical and equilibrium calculations for sulfur and phosphorus impurities, the determination of the complete kinetics of hydrogen reduction and bench-scale testing of the suspension reduction process using a large laboratory flash reactor.

  1. Acoustic concentration of particles in fluid flow

    Science.gov (United States)

    Ward, Michael D.; Kaduchak, Gregory

    2010-11-23

    An apparatus for acoustic concentration of particles in a fluid flow includes a substantially acoustically transparent membrane and a vibration generator that define a fluid flow path therebetween. The fluid flow path is in fluid communication with a fluid source and a fluid outlet and the vibration generator is disposed adjacent the fluid flow path and is capable of producing an acoustic field in the fluid flow path. The acoustic field produces at least one pressure minima in the fluid flow path at a predetermined location within the fluid flow path and forces predetermined particles in the fluid flow path to the at least one pressure minima.

  2. Radiotracer gadolinium pre-concentration and detection

    International Nuclear Information System (INIS)

    Radiotracer 153Gd is a low-energy γ-emitter with 8-months half-life, is used as line sources and in calibration phantoms, to ensure that nuclear medicine imaging systems operate correctly and produce useful images of radioisotope distribution inside the patient. The used radiotracer gadolinium is generally disposed as laboratory effluent in different testing experiments. Hence, this toxic radiotracer gadolinium is required to be eliminated from these effluents before disposal to nature. In this paper performance of a 'radiotracer gadolinium selective pre-concentrator' viz, polyacrylamide hydroxamate (PHOA) chelator has been studied for removal and recovery of gadolinium

  3. Scandium concentration from wastes of titanium production

    International Nuclear Information System (INIS)

    The results of investigations concerning the establishment of physical and chemical regularities of behaviour of scandium and its accompanying metals in sorption processes, extraction with hard extractants, deposition etc. are generalized. The row of technological schemes for scandium extraction out of processed melt of production of titanium tetrachloride with obtaining of scandium concentrates (up to 95% of scandium oxide) is developed. These schemes are tested in pilot-industrial conditions and put into practice. It is shown that improved deposition-sorption (extraction) technology for scandium extraction with accompanied utilization of iron, chromium and manganese compounds as commercial products is the most effective one

  4. Natural radioactivity concentrations in building materials

    International Nuclear Information System (INIS)

    As part of our study program on environmental radiation levels is buildings, we have undertaken to measure the natural radioactivity, such as radium-226, thorium-232, and potassium-40 in various inorganic building materials. The specimens of their materials include cements, aggregates, concretes, asbestos cement slates, tiles, gypsum boards, rock wool boards, bricks, wall clays, soils, phosphorous ore, zirconia, zircon flower and zircon sand that used in Japan. The ranges and mean values of natural radioactivity concentrations existing in their materials are tabulated and evaluated. (author)

  5. Extraction of Am3+ from concentrated solutions

    International Nuclear Information System (INIS)

    Diamond and coworkers published a series of valuable papers on the extraction and ion exchange behavior of metal cations in concentrated aqueous of mineral acids. The authors have extended such studies to the behavior of Am3+ in solutions of NX where N = H+, Li+, Na+, and X- = ClO4-, Cl- and NO3-. The variation of the extraction coefficient is interpreted in terms of ion exchange, complexation and salting out behavior. These effects on Am3+ extraction are contrasted with that on Ca2+ and Zn2+ extraction

  6. Double curvature mirrors for linear concentrators

    Science.gov (United States)

    Lance, Tamir; Ackler, Harold; Finot, Marc

    2012-10-01

    Skyline Solar's medium concentration photovoltaic system uses quasi-parabolic mirrors and one axis tracking. Improvements in levelized cost of energy can be achieved by effective management of non-uniformity of the flux line on the panels. To reduce non uniformity of the flux line due to mirror to mirror gaps, Skyline developed a dual curvature mirror that stretches the flux line along the panel. Extensive modeling and experiments have been conducted to analyze the impact of this new design and to optimize the design.

  7. Advertising and concentration in the brewing industry

    DEFF Research Database (Denmark)

    Madsen, Erik Strøjer; Wu, Yanqing

    The opening of the markets in East Asia and Eastern Europe in the 1990s changed the structure of the beer markets and in the following years a large wave of mergers and acquisitions took place. The paper tracks the development in industry concentrations from 2002 to 2012, discusses some of the main...... drivers behind this development and points to economies of scale in advertising as a main pay-off from mergers and acquisitions. Using firm-level data both from the American market and the world market, the estimations verify significant economies of scale in marketing and distribution costs. Based...

  8. Aquatic nitrogen transformations at low oxygen concentrations.

    OpenAIRE

    Downes, M T

    1988-01-01

    Nitrite and nitrous oxide made up 40% of the hypolimnetic dissolved inorganic nitrogen in mesotrophic Lake Rotoiti, New Zealand, prior to hypolimnetic anoxia. Up to 120 mg of N m-3 as nitrite and 20 mg of N m-3 as nitrous oxide accumulated, whereas dissolved-oxygen concentrations remained between 1.0 and 0.2 g m-3 and were totally consumed when the hypolimnion became completely anoxic. Assays of water column nitrification potentials, together with measurements of the relative rates of nitrate...

  9. Cylinder light concentrator and absorber: theoretical description.

    Science.gov (United States)

    Kildishev, Alexander V; Prokopeva, Ludmila J; Narimanov, Evgenii E

    2010-08-01

    We present a detailed theoretical description of a broadband omnidirectional light concentrator and absorber with cylinder geometry. The proposed optical "trap" captures nearly all the incident light within its geometric cross-section, leading to a broad range of possible applications--from solar energy harvesting to thermal light emitters and optoelectronic components. We have demonstrated that an approximate lamellar black-hole with a moderate number of homogeneous layers, while giving the desired ray-optical performance, can provide absorption efficiencies comparable to those of ideal devices with a smooth gradient in index. PMID:20721056

  10. Effects of ambient oxygen concentration on soot temperature and concentration for biodiesel and diesel spray combustion

    KAUST Repository

    Zhang, Ji

    2015-06-01

    Ambient oxygen concentration, a key variable directly related to exhaust gas recirculation (EGR) levels in diesel engines, plays a significant role in particulate matter (PM) and nitrogen oxides (NOx) emissions. The utilization of biodiesel in diesel engines has been investigated over the last decades for its renewable characteristics and lower emissions compared to diesel. In an earlier work, we demonstrated that the soot temperature and concentration of biodiesel were lower than diesel under regular diesel engine conditions without EGR. Soot concentration was quantified by a parameter called KL factor. As a continuous effort, this paper presents an experimental investigation of the ambient oxygen concentration on soot temperature and KL factor during biodiesel and diesel spray combustion. The experiment was implemented in a constant volume chamber system, where the ambient oxygen concentration varied from 21 to 10% and the ambient temperature was kept to 1,000 K. A high speed two-color pyrometry technique was used to measure transient soot temperature and the KL factor of the spray flame. The soot temperature of biodiesel is found to be lower than that of diesel under the same conditions, which follows the same trend from our previous results found when the ambient temperature changes to 21% oxygen conditions. A reduction in ambient oxygen concentration generally reduces the soot temperature for both fuels. However, this is a complicated effect on soot processes as the change of oxygen concentration greatly affects the balance between soot formation and oxidation. The KL factor is observed to be the highest at 12% O2 for diesel and 18% O2 for biodiesel, respectively. On the other hand, the 10% O2 condition shows the lowest KL factor for both fuels. These results can provide quantitative experimental evidences to optimize the ambient oxygen concentration for diesel engines using different fuels for better emissions characteristics. © 2014 American Society of

  11. Numerical simulation of concentrating solar collector P2CC with a small concentrating ratio

    OpenAIRE

    Stefanović Velimir P.; Pavlović Saša R.; Ilić Marko N.; Apostolović Nenad S.; Kuštrimović Dragan D.

    2012-01-01

    Solar energy may be practically utilized directly through transformation into heat, electrical or chemical energy. A physical and mathematical model is presented, as well as a numerical procedure for predicting thermal performances of the P2CC solar concentrator. The demonstrated prototype has the reception angle of 110° at concentration ratio CR = 1.38, with the significant reception of diffuse radiation. The solar collector P2CC is designed for the area of middle temperature conversio...

  12. Luminescent and Non-Luminescent Solar Concentrators: Challenges andd Progress

    NARCIS (Netherlands)

    De Boer, D.K.G.

    2012-01-01

    Luminescent concentrators would allow for high concentration if losses by reabsorption and escape could be minimized. We present new phosphors and filters that facilitate this. Another type of lightguide-based concentrators, diffraction-based, is discussed as well.

  13. DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

    Energy Technology Data Exchange (ETDEWEB)

    NA

    2004-11-22

    The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this modeling activity is to predict dissolved concentrations or solubility limits for 14 elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) important to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are in the form of tabulated functions with pH and log (line integral) CO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. The output data from this report are fundamental inputs for Total System Performance Assessment for the License Application (TSPA-LA) to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for all of the actinides. These models cover broad ranges of environmental conditions so that they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or otherwise addressed.

  14. Simulation of an electrowetting solar concentration cell

    Science.gov (United States)

    Khan, Iftekhar; Rosengarten, Gary

    2015-09-01

    Electrowetting control of liquid lenses has emerged as a novel approach for solar tracking and concentration. Recent studies have demonstrated the concept of steering sunlight using thin electrowetting cells without the use of any bulky mechanical equipment. Effective application of this technique may facilitate designing thin and flat solar concentrators. Understanding the behavior of liquid-liquid and liquid-solid interface of the electrowetting cell through trial and error experimental processes is not efficient and is time consuming. In this paper, we present a simulation model to predict the liquid-liquid and liquid-solid interface behavior of electrowetting cell as a function of various parameters such as applied voltage, dielectric constant, cell size etc. We used Comsol Multiphysics simulations incorporating experimental data of different liquids. We have designed both two dimensional and three dimensional simulation models, which predict the shape of the liquid lenses. The model calculates the contact angle using the Young-Lippman equation and uses a moving mesh interface to solve the Navier-stokes equation with Navier slip wall boundary condition. Simulation of the electric field from the electrodes is coupled to the Young-Lippman equation. The model can also be used to determine operational characteristics of other MEMS electrowetting devices such as electrowetting display, optical switches, electronic paper, electrowetting Fresnel lens etc.

  15. Cast Stone Formulation At Higher Sodium Concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M.; Edwards, T. A.; Roberts, K. B.

    2013-10-02

    A low temperature waste form known as Cast Stone is being considered to provide supplemental Low Activity Waste (LAW) immobilization capacity for the Hanford site. Formulation of Cast Stone at high sodium concentrations is of interest since a significant reduction in the necessary volume of Cast Stone and subsequent disposal costs could be achieved if an acceptable waste form can be produced with a high sodium molarity salt solution combined with a high water to premix (or dry blend) ratio. The objectives of this study were to evaluate the factors involved with increasing the sodium concentration in Cast Stone, including production and performance properties and the retention and release of specific components of interest. Three factors were identified for the experimental matrix: the concentration of sodium in the simulated salt solution, the water to premix ratio, and the blast furnace slag portion of the premix. The salt solution simulants used in this study were formulated to represent the overall average waste composition. The cement, blast furnace slag, and fly ash were sourced from a supplier in the Hanford area in order to be representative. The test mixes were prepared in the laboratory and fresh properties were measured. Fresh density increased with increasing sodium molarity and with decreasing water to premix ratio, as expected given the individual densities of these components. Rheology measurements showed that all of the test mixes produced very fluid slurries. The fresh density and rheology data are of potential value in designing a future Cast Stone production facility. Standing water and density gradient testing showed that settling is not of particular concern for the high sodium compositions studied. Heat of hydration measurements may provide some insight into the reactions that occur within the test mixes, which may in turn be related to the properties and performance of the waste form. These measurements showed that increased sodium

  16. Cast Stone Formulation At Higher Sodium Concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M.; Roberts, K. A.; Edwards, T. B.

    2013-09-17

    A low temperature waste form known as Cast Stone is being considered to provide supplemental Low Activity Waste (LAW) immobilization capacity for the Hanford site. Formulation of Cast Stone at high sodium concentrations is of interest since a significant reduction in the necessary volume of Cast Stone and subsequent disposal costs could be achieved if an acceptable waste form can be produced with a high sodium molarity salt solution combined with a high water to premix (or dry blend) ratio. The objectives of this study were to evaluate the factors involved with increasing the sodium concentration in Cast Stone, including production and performance properties and the retention and release of specific components of interest. Three factors were identified for the experimental matrix: the concentration of sodium in the simulated salt solution, the water to premix ratio, and the blast furnace slag portion of the premix. The salt solution simulants used in this study were formulated to represent the overall average waste composition. The cement, blast furnace slag, and fly ash were sourced from a supplier in the Hanford area in order to be representative. The test mixes were prepared in the laboratory and fresh properties were measured. Fresh density increased with increasing sodium molarity and with decreasing water to premix ratio, as expected given the individual densities of these components. Rheology measurements showed that all of the test mixes produced very fluid slurries. The fresh density and rheology data are of potential value in designing a future Cast Stone production facility. Standing water and density gradient testing showed that settling is not of particular concern for the high sodium compositions studied. Heat of hydration measurements may provide some insight into the reactions that occur within the test mixes, which may in turn be related to the properties and performance of the waste form. These measurements showed that increased sodium

  17. Cast Stone Formulation At Higher Sodium Concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M.; Roberts, K. A.; Edwards, T. B.

    2014-02-28

    A low temperature waste form known as Cast Stone is being considered to provide supplemental Low Activity Waste (LAW) immobilization capacity for the Hanford site. Formulation of Cast Stone at high sodium concentrations is of interest since a significant reduction in the necessary volume of Cast Stone and subsequent disposal costs could be achieved if an acceptable waste form can be produced with a high sodium molarity salt solution combined with a high water to premix (or dry blend) ratio. The objectives of this study were to evaluate the factors involved with increasing the sodium concentration in Cast Stone, including production and performance properties and the retention and release of specific components of interest. Three factors were identified for the experimental matrix: the concentration of sodium in the simulated salt solution, the water to premix ratio, and the blast furnace slag portion of the premix. The salt solution simulants used in this study were formulated to represent the overall average waste composition. The cement, blast furnace slag, and fly ash were sourced from a supplier in the Hanford area in order to be representative. The test mixes were prepared in the laboratory and fresh properties were measured. Fresh density increased with increasing sodium molarity and with decreasing water to premix ratio, as expected given the individual densities of these components. Rheology measurements showed that all of the test mixes produced very fluid slurries. The fresh density and rheology data are of potential value in designing a future Cast Stone production facility. Standing water and density gradient testing showed that settling is not of particular concern for the high sodium compositions studied. Heat of hydration measurements may provide some insight into the reactions that occur within the test mixes, which may in turn be related to the properties and performance of the waste form. These measurements showed that increased sodium

  18. Minimal inhibitory concentrations of modern topical antimicrobials

    Directory of Open Access Journals (Sweden)

    T. N. Vorontsova

    2014-01-01

    Full Text Available Aim. To measure minimal inhibitory concentration (MIC values for modern topical antimicrobials against common ocular pathogens.Methods.Antimicrobials most commonly used in ophthalmology (fluoroquinolones and aminoglycosides are dose-dependent drugs, i.e., the rate of microbial death increases in direct proportion to their concentrations. To determine MICs, we applied Hi Comb MIC Test (E-test. 105 patients aged 2 months through 7 years which were diagnosed with various inflammatory disorders of anterior segment were  xamined. MIC values for most commonly used antimicrobials, i.e., ciprofloxacin / Cipromed (Sentiss Pharma, Gurgaon, India, ofloxacin / Floxal (Baush & Lomb, Rochester, New-York, levofloxacin / Signicef (Sentiss Pharma, Gurgaon, India, moxifloxacin / Vigamox (Alcon, Fort Worth, Texas, gatifloxacin / Zymar (Allergan, Irvine, California, and tobramycin / Tobrex (Alcon, Fort Worth, Texas, were measured.Results. The analysis revealed that the most effective antibacterial drug against microbial isolates in children (i.e., Staphylococci spp. was levofloxacin. MIC for this agent against Streptococci spp. and Gram-negative microbes was low as well. Moxifloxacin is preferred for the treatment of ocular inflammation provoked by Streptococci spp. as MIC of this antimicrobial against Streptococci spp. was the lowest. MIC of ciprofloxacin against Gram-negative flora was the lowest. These data demonstrate generally recognized high efficacy of this drug. MIC value for tobramycin against all bacterial isolates was the highest.

  19. Specific dietary patterns and concentrations of adiponectin

    Directory of Open Access Journals (Sweden)

    Vajihe Izadi

    2015-01-01

    Full Text Available Background: One of the adipokines mostly secreted from adipose tissue is adiponectin. Adiponectin is well known as the anti-diabetic, anti-obesity and cardio-protective factor. Present study focused on the review the previous studies about relationship between adherence to healthy dietary pattern, independent of one or two special dietary components, and concentration of adiponectin. Materials and Methods: We searched in PubMed search engine from 2003 to July 2014 using the following key words: Healthy dietary pattern, mediterranean dietary pattern, dietary pattern, diet intervention and adiponectin and adipokines. Then, we recruited 10 articles to review in the present study. Results: Cohort studies that are examined this relationship among women showed the strong positive association in this regard. According to cross-sectional studies adherence to healthy dietary pattern like Mediterranian intervention with moderate weight loss had a positive association with concentration of adiponectin. Conclusion: It seems that adherents to the healthy dietary patterns have great levels of circulating adiponectin. However, it is not clear that whether the separate components of healthy dietary patterns like good sources of fats or protein or fibers mostly have important roles in these beneficial effects of such dietary patterns or not.

  20. Pollution concentration estimates in ecologically important zones

    Energy Technology Data Exchange (ETDEWEB)

    Skiba, Y.N. [Mexico City Univ. (Mexico). Center for Atmospheric Sciences

    1995-12-31

    Method based on using the pollutant transport equation and the adjoint technique is described here for estimating the pollutant concentration level in ecologically important zones. The method directly relates the pollution level in such zones with the power of the pollution sources and the initial pollution field. Assuming that the wind or current velocities are known (from climatic data or dynamic model), the main and adjoint pollutant transport equations can be considered in a limited area to solve such theoretically and practically important problems as: (1) optimal location of new industries in a given region with the aim to minimize the pollution concentration in certain ecologically important zones, (2) optimization of emissions from operating industries, (3) detection of the plants violating sanitary regulations, (4) analysis of the emissions coming from the vehicle traffic (such emissions can be included in the model by means of the linear pollution sources located along the main roadways), (5) estimation of the oil pollution in various ecologically important oceanic (sea) zones in case of accident with the oil tanker, (6) evaluation of the sea water desalination level in estuary regions, and others. These equations considered in a spherical shell domain can also be applied to the problems of transporting the pollutants from a huge industrial complex, or from the zone of an ecological catastrophe similar to the Chernobyl one

  1. Erbium concentration dependent absorbance in tellurite glass

    International Nuclear Information System (INIS)

    Enhancing the optical absorption cross-section in topically important rare earth doped tellurite glasses is challenging for photonic devices. Controlled synthesis and detailed characterizations of the optical properties of these glasses are important for the optimization. The influence of varying concentration of Er3+ ions on the absorbance characteristics of lead tellurite glasses synthesized via melt-quenching technique are investigated. The UV-Vis absorption spectra exhibits six prominent peaks centered at 490, 526, 652, 800, 982 and 1520 nm ascribed to the transitions in erbium ion from the ground state to the excited states 4F7/2, 2H11/2, 4F9/2, 4I9/2, 2H11/2 and 4I13/2, respectively. The results are analyzed by means of optical band gap Eg and Urbach energy Eu. The values of the energy band gap are found decreased from 2.82 to 2.51 eV and the Urbach energy increased from 0.15 to 0.24 eV with the increase of the Er2O3 concentration from 0 to 1.5 mol%. The excellent absorbance of the prepared tellurite glasses makes them suitable for fabricating solid state lasers

  2. NO concentration imaging in turbulent nonpremixed flames

    Energy Technology Data Exchange (ETDEWEB)

    Schefer, R.W. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The importance of NO as a pollutant species is well known. An understanding of the formation characteristics of NO in turbulent hydrocarbon flames is important to both the desired reduction of pollutant emissions and the validation of proposed models for turbulent reacting flows. Of particular interest is the relationship between NO formation and the local flame zone, in which the fuel is oxidized and primary heat release occurs. Planar imaging of NO provides the multipoint statistics needed to relate NO formation to the both the flame zone and the local turbulence characteristics. Planar imaging of NO has been demonstrated in turbulent flames where NO was seeded into the flow at high concentrations (2000 ppm) to determine the gas temperature distribution. The NO concentrations in these experiments were significantly higher than those expected in typical hydrocarbon-air flames, which require a much lower detectability limit for NO measurements. An imaging technique based on laser-induced fluorescence with sufficient sensitivity to study the NO formation mechanism in the stabilization region of turbulent lifted-jet methane flames.

  3. Multiband solar concentrator using transmissive dichroic beamsplitting

    Science.gov (United States)

    Karp, Jason H.; Ford, Joseph E.

    2008-08-01

    Significant efficiency increases in photovoltaic power conversion are due to improved absorption over the broad spectrum of the sun. Semiconductors have an efficiency peak at a specific wavelength associated with the material band gap. The current trend towards high-efficiency photovoltaics involves multi-junction cells where several semiconductors are grown on top of one another creating a layered device with a broad spectral response. Fabrication is a difficult and expensive process that results in small area solar cells. An alternative approach uses dielectric mirrors to optically separate the incident light by reflecting one spectral band while transmitting another. Spectral splitting is simulated within a 10x non-imaging concentrator. The optical system may be concatenated into large arrays and incorporates two separated ray paths exiting at a common plane. Optimized photovoltaic cells can be interleaved on a single circuit board, improving packaging and thermal management compared to orthogonal arrangements. The entire concentrator can be molded from glass or acrylic and requires a dichroic coating as the only reflector. Average collection efficiencies above 84% are realized within 40°x16° angular acceptance.

  4. Elevated hair cortisol concentrations in endurance athletes.

    Science.gov (United States)

    Skoluda, Nadine; Dettenborn, Lucia; Stalder, Tobias; Kirschbaum, Clemens

    2012-05-01

    Engaging in intensive aerobic exercise, specifically endurance sports, is associated with HPA axis activation indicated by elevated cortisol levels. Whether the repeated short-term elevations in cortisol levels result in higher long-term cortisol exposure of endurance athletes has been difficult to examine since traditional methods of cortisol assessments (saliva, blood, urine) reflect only relatively short time periods. Hair segment analysis provides a new method to assess cumulative cortisol secretion over prolonged time periods in a retrospective fashion. The aim of this study was to investigate cumulative cortisol secretion over several months reflecting intensive training and competitive races by examining hair cortisol levels of endurance athletes. Hair samples were obtained from 304 amateur endurance athletes (long-distance runners, triathletes, cyclists) and 70 controls. Cortisol concentrations were determined in the first to third 3-cm hair segments most proximal to the scalp. In addition, self-report measures of training volume were obtained. Endurance athletes exhibited higher cortisol levels in all three hair segments compared to controls (p<.001). Positive correlations between the cortisol concentration in the first hair segment and each indicator of training volume were found (all p<.01). These data suggest that repeated physical stress of intensive training and competitive races among endurance athletes is associated with elevated cortisol exposure over prolonged periods of time. These findings may have important implications with regard to somatic and mental health of athletes which should be investigated in future research. PMID:21944954

  5. Study of Nitrogen Concentration in Silicon Carbide

    Science.gov (United States)

    Wang, Hui; Yan, Cheng-Feng; Kong, Hai-Kuan; Chen, Jian-Jun; Xin, Jun; Shi, Er-Wei; Yang, Jian-Hua

    2013-06-01

    This work focused on studying the nitrogen concentration ( C N) in SiC. The variations of C N in the synthesis of SiC powder as well as the transport during SiC crystal growth have been investigated for broad ranges of temperature and Ar pressure. Before SiC crystal growth, SiC powders were synthesized from high-purity silicon and carbon powders. The concentrations of nitrogen, free C, and free Si in the as-prepared powders were all measured. C N in the SiC source powder decreased with increasing temperature and decreasing Ar pressure, whereas it did not show a remarkable trend with the molar ratio of free Si to free C. SiC crystal was then grown by the physical vapor transport (PVT) technique using the as-prepared powder. The distribution of C N in the remaining material indirectly indicated the temperature field of crystal growth. In addition, compared with introducing N2 during SiC crystal growth, doping with nitrogen during synthesis of the SiC source powder might be a better method to control C N in SiC crystals.

  6. Future Avenues to Decrease Uremic Toxin Concentration.

    Science.gov (United States)

    Vanholder, Raymond C; Eloot, Sunny; Glorieux, Griet L R L

    2016-04-01

    In this article, we review approaches for decreasing uremic solute concentrations in chronic kidney disease and in particular, in end-stage renal disease (ESRD). The rationale to do so is the straightforward relation between concentration and biological (toxic) effect for most toxins. The first section is devoted to extracorporeal strategies (kidney replacement therapy). In the context of high-flux hemodialysis and hemodiafiltration, we discuss increasing dialyzer blood and dialysate flows, frequent and/or extended dialysis, adsorption, bioartificial kidney, and changing physical conditions within the dialyzer (especially for protein-bound toxins). The next section focuses on the intestinal generation of uremic toxins, which in return is stimulated by uremic conditions. Therapeutic options are probiotics, prebiotics, synbiotics, and intestinal sorbents. Current data are conflicting, and these issues need further study before useful therapeutic concepts are developed. The following section is devoted to preservation of (residual) kidney function. Although many therapeutic options may overlap with therapies provided before ESRD, we focus on specific aspects of ESRD treatment, such as the risks of too-strict blood pressure and glycemic regulation and hemodynamic changes during dialysis. Finally, some recommendations are given on how research might be organized with regard to uremic toxins and their effects, removal, and impact on outcomes of uremic patients. PMID:26500179

  7. A statistical evaluation of asbestos air concentrations

    International Nuclear Information System (INIS)

    Both area and personal air samples collected during an asbestos abatement project were matched and statistically analysed. Among the many parameters studied were fibre concentrations and their variability. Mean values for area and personal samples were 0.005 and 0.024 f cm--3 of air, respectively. Summary values for area and personal samples suggest that exposures are low with no single exposure value exceeding the current OSHA TWA value of 0.1 f cm-3 of air. Within- and between-worker analysis suggests that these data are homogeneous. Comparison of within- and between-worker values suggests that the exposure source and variability for abatement are more related to the process than individual practices. This supports the importance of control measures for abatement. Study results also suggest that area and personal samples are not statistically related, that is, there is no association observed for these two sampling methods when data are analysed by correlation or regression analysis. Personal samples were statistically higher in concentration than area samples. Area sampling cannot be used as a surrogate exposure for asbestos abatement workers. (author)

  8. Concentrations of lithium in Chinese coals

    Energy Technology Data Exchange (ETDEWEB)

    Yuzhuang Sun; Yanheng Li; Cunliang Zhao; Mingyue Lin; Jinxi Wang; Shenjun Qin [Hebei University of Engineering, Handan (China). Key Laboratory of Resource Exploration Research of Hebei Province

    2010-04-15

    Lithium is an important energy metal. Its concentrations in coals have been studied by many geologists. Its average content is only 14 mg/kg in the coals of the world. Lithium has never been reported as a coal associated deposit before. In order to study the concentrations in Chinese coals, 159 coal and gangue samples were taken from six coal mines and were determined by ICP-MS and the minerals in the samples were identified by X-ray powder diffraction. The results indicate that the Li contents in the coal samples from the Antaibao Coal Mine have reached the industry grade of coal associated deposits. In Tongxing Coal Mine, Li contents in the coal floor rock samples have reached the industry grade of independent lithium deposits. Main minerals are polylithionite, triphylite, zinnwaldite, lithionite and cookeite, which were transported into the peats. Therefore, lithium enriched is most likely in the synsedimentary stage in both coal mines. Furthermore, a revised average Li content in Chinese coals was given.

  9. Comparative survey of outdoor, residential and workplace radon concentrations

    OpenAIRE

    Barros, Nirmalla; Field, Dan W.; Steck, Daniel J.; Field, R. William

    2014-01-01

    This study investigated radon concentrations in above-ground (i.e. first floor) workplace in Missouri and compared them with above-ground radon concentrations in nearby homes and outdoor locations. This study also examined the potential utility of using home and outdoor radon concentrations to predict the radon concentration at a nearby workplace (e.g. county agencies and schools). Even though workplace radon concentrations were not statistically different from home radon concentrations, the ...

  10. Concentration ratio of radon progeny in air

    International Nuclear Information System (INIS)

    Investigations have been made on the concentration ratio of radon progeny in air. Data have been acquired intermittently since 1988 using alpha spectroscopic method around the author's office that is located in the northeastern part of Japan. Clarifying the behavior of radon progeny is an issue of wide importance to radiation protection, predicting earthquakes, etc. Let Rabc=ECRn(RaA)/{ECRn(RaB) + ECRn(RaC)}; the concentration ratio, Rabc, is relevant to the stability of the air. Statistical and time series analyses indicated several interesting results. To examine the log-normal distribution, Lilliefors test was made for logarithm of outdoor data every one year. Rabc passed the test 6 times for 9 years, while Radon progeny passed 8 times. Outdoor data indicated that the value of Rabc was lower in the morning, in other world, the air was more stable in the morning than in the afternoon. To see the seasonal variation, one-way layout analysis was made for four groups of data, i.e., spring (March to May), summer (June to August), autumn (September to November), and winter (December to February). Rabc indicated significantly higher level in spring and winter, in other word, air was stable in summer and autumn. Time series analysis was made for various variables; power spectra were estimated with autoregressive model that is equivalent to maximum entropy method. Power spectrum for Rabc was most similar to that of wind speed. One-year period, that is always remarkable for radon progeny, was not significant for Rabc. Three- to nine-day periods were often seen for Rabc, radon progeny, wind speed, and atmospheric pressure. These several-day periods are probably attributed to the passage of air masses. Twenty-day to thirty-day peak may be attributed to meteorological phenomena corresponding to the rotation period of the sun. Temperature indicated no significant periodicity except overwhelming one-year period. Wind speed is well known to affect the radon progeny concentration

  11. Polarimetric Retrievals of Cloud Droplet Number Concentrations

    Science.gov (United States)

    Sinclair, K.; Cairns, B.; Hair, J. W.; Hu, Y.; Hostetler, C. A.

    2014-12-01

    Cloud droplet number concentration (CDNC) is one of the most significant microphysical properties of liquid clouds and is essential for the understanding of aerosol-cloud interaction. It impacts radiative forcing, cloud evolution, precipitation, global climate and, through observation, can be used to monitor the cloud albedo effect, or the first indirect effect. The IPCC's Fifth Assessment Report continues to consider aerosol-cloud interactions as one of the largest uncertainties in radiative forcing of climate. The SABOR experiment, which was a NASA-led ship and air campaign off the east coast of the United States during July and August of 2014, provided an opportunity for the Research Scanning Polarimeter (RSP) to develop and cross-validate a new approach of sensing CDNC with the High Spectral Resolution Lidar (HSRL). The RSP is an airborne prototype of the Aerosol Polarimetry Sensor (APS) that was on-board the Glory satellite. It is a scanning sensor that provides high-precision measurements of polarized and full-intensity radiances at multiple angles over a wide spectral range. The distinctive feature of the polarimetric technique is that it does not make any assumption of the liquid water profile within the cloud. The approach involves (1) estimating the droplet size distribution from polarized reflectance observations in the rainbow, (2) using polarized reflectance to estimate above cloud water vapor and total reflectance to find how much near infra-red light is being absorbed in clouds, (3) finding cloud physical thickness from the absorption and cloud top pressure retrievals assuming a saturated mixing ratio for water vapor and (4) determining the cloud droplet number concentration from the physical thickness and droplet size distribution retrievals. An overview of the polarimetric technique will be presented along with the results of applying the new approach to SABOR campaign data. An analysis of the algorithm's performance when compared with the HSRL

  12. CFC concentrations in fresh groundwater in Latvia

    Science.gov (United States)

    Bikše, J.; DÄ`liĆa, A.; Babre, A.; RetiÄ·e, I.; Raga, B.; PÄ`rkone, E.

    2012-04-01

    One of the main issues in groundwater studies is groundwater age, also known as residence time. This is important for investigating the groundwater filtration rate and to solve variety issues of groundwater use, management and protection. Groundwater age studies in Latvia have been rare, and the latest study, which defined the new results of age of groundwater using CFC dating method, was during years 2002 - 2006 and it was carried out by Denmark and Greenland Geological Survey (GEUS) and the Latvian State Geological Survey as a joint study on the impact of agriculture on groundwater quality in Latvia. Within the project "Interdisciplinary research groups and model system for groundwater studies" (PUMA) the studies of groundwater age by CFCs and 3H methods is continued. The concentration of tritium will be determined in about 60 samples, but the CFC concentration is now analyzed in 39 samples because previous studies have shown that Latvian CFC method is appropriate for aquifers to an average depth of 30-50 m. CFCs concentrations were analyzed in the laboratory at GEUS after Busenberg and Plummer described method by gas chromatography equipped with an EDC detector. Interpretation of the results was carried out by laboratory expert Troels Laier. Samples are taken on both from the unconfined aquifer and the first confined aquifer, the sampling interval varies from 5-10 m up to 120-130 m for tritium analysis and up to 80 m depth for most CFC analysis except one sample that comes from 128 m depth. It is stated that most of determined groundwater from both - confined and unconfined aquifer - has residence time of 35-55 years. So far, the results suggest that groundwater movement is fairly rapid in places where fractured dolomite forms the aquifer as the water residence time at 60-70 m depth is only 35-55 years. On the other hand, the composition of overlying Quaternary deposits (clay, glacial till loam or sand, sand - gravel sediments) has great importance on variations

  13. Comparative survey of outdoor, residential and workplace radon concentrations

    International Nuclear Information System (INIS)

    This study investigated radon concentrations in above-ground (i.e. first floor) workplace in Missouri and compared them with above-ground radon concentrations in nearby homes and outdoor locations. This study also examined the potential utility of using home and outdoor radon concentrations to predict the radon concentration at a nearby workplace (e.g. county agencies and schools). Even though workplace radon concentrations were not statistically different from home radon concentrations, the radon concentration at a particular home, or outdoor location, was a poor predictor of the radon concentration at a nearby workplace. Overall, 9.6 and 9.9 % of homes and workplace, respectively, exhibited radon concentrations of ≥148 Bq m-3. Because of the percentage of workplace with elevated radon concentrations, the results suggest that additional surveys of workplace radon concentrations are needed, especially in areas of high radon potential, to assess the contribution of workplace radon exposure to an individual's overall radon exposure. (authors)

  14. Towards a flat 45%-efficient concentrator module

    Energy Technology Data Exchange (ETDEWEB)

    Mohedano, Rubén, E-mail: rmohedano@lpi-europe.com; Hernandez, Maikel; Vilaplana, Juan; Chaves, Julio; Sorgato, S.; Falicoff, Waqidi [LPI, Altadena, CA, USA and Madrid (Spain); Miñano, Juan C.; Benitez, Pablo [LPI, Altadena, CA, USA and Madrid (Spain); Universidad Politécnica de Madrid (UPM), Campus de Montegancedo, Madrid (Spain)

    2015-09-28

    The so-called CCS{sup 4}FK is an ultra-flat photovoltaic system of high concentration and high efficiency, with potential to convert, ideally, the equivalent of a 45% of direct solar radiation into electricity by optimizing the usage of sun spectrum and by collecting part of the diffuse radiation, as a flat plate does. LPI has recently finished a design based on this concept and is now developing a prototype based on this technology, thanks to the support of FUNDACION REPSOL-Fondo de Emprendedores, which promotes entrepreneur projects in different areas linked to energy. This works shows some details of the actual design and preliminary potential performance expected, according to accurate spectral simulations.

  15. Towards a flat 45%-efficient concentrator module

    Science.gov (United States)

    Mohedano, Rubén; Hernandez, Maikel; Vilaplana, Juan; Chaves, Julio; Miñano, Juan C.; Benitez, Pablo; Sorgato, S.; Falicoff, Waqidi

    2015-09-01

    The so-called CCS4FK is an ultra-flat photovoltaic system of high concentration and high efficiency, with potential to convert, ideally, the equivalent of a 45% of direct solar radiation into electricity by optimizing the usage of sun spectrum and by collecting part of the diffuse radiation, as a flat plate does. LPI has recently finished a design based on this concept and is now developing a prototype based on this technology, thanks to the support of FUNDACION REPSOL-Fondo de Emprendedores, which promotes entrepreneur projects in different areas linked to energy. This works shows some details of the actual design and preliminary potential performance expected, according to accurate spectral simulations.

  16. Caesium concentration in the Pakistani diet

    International Nuclear Information System (INIS)

    Daily dietary intakes of radioactive and non-radioactive caesium for the Pakistani population were measured. Food samples were collected on market basket method and were analysed using Instrumental Neutron Activation Analysis technique. The radioactive caesium (137Cs) in these samples was below the detectable limit, i.e. 1 mBq g-1. The geometric mean of the mass fraction of stable caesium was 9.56x1.53 ng g-1. The estimated daily dietary intake of caesium was 5.65x1.53 μg d-1 or 0.088 μg kg-1 of body weight of the reference Pakistani man weighing 64 kg. These values are 38.2% smaller than the recommended ICRP values for a 70 kg standard man. However, caesium concentration in the Pakistani diet is comparable with other reported values in the literature

  17. Urine protein concentration estimation for biomarker discovery.

    Science.gov (United States)

    Mistry, Hiten D; Bramham, Kate; Weston, Andrew J; Ward, Malcolm A; Thompson, Andrew J; Chappell, Lucy C

    2013-10-01

    Recent advances have been made in the study of urinary proteomics as a diagnostic tool for renal disease and pre-eclampsia which requires accurate measurement of urinary protein. We compared different protein assays (Bicinchoninic acid (BCA), Lowry and Bradford) against the 'gold standard' amino-acid assay in urine from 43 women (8 non-pregnant, 34 pregnant, including 8 with pre-eclampsia). BCA assay was superior to both Lowry and Bradford assays (Bland Altman bias: 0.08) compared to amino-acid assay, which performed particularly poorly at higher protein concentrations. These data highlight the need to use amino-acid or BCA assays for unprocessed urine protein estimation. PMID:26103798

  18. Complex concentrate pretreatment FY 1986 progress report

    International Nuclear Information System (INIS)

    After of the transuranic elements are removed from complex concentrate waste by the TRUEX process, the remaining waste will be grouted for final storage. The purpose of this project, conducted at the Pacific Northwest Laboratory (PNL), is to support a future decision to grout the complexant waste without destroying the organic contents. In work performed this year, it has been demonstrated that grouts with acceptable parameters for the Transportable Grout Facility can be made using actual waste. The acceptability of these grouts from a regulatory view seems to be less of a problem than was thought at this time last year. None of the organics found in the waste are included on the US Environmental Protection Agency's Hazardous Chemicals List. 7 refs., 12 figs., 4 tabs

  19. Reduction of radon daughter concentrations in structures

    International Nuclear Information System (INIS)

    A structure was identified in Salt Lake City wherein uranium mill tailings had been used in the construction and where unusually high levels of radon daughter concentrations (RDC's) existed. The physical and radiological characteristics of the structure were assessed. Ventilation techniques were investigated to assess their effectiveness in reducing RDC's. A preferred set of equipment was identified, installed in the structure and operated to reduce RDC's. Parametric studies were conducted to determine if supplying fresh air or recirculating air through electrostatic precipitators is more effective in reducing RDC's. Fresh air was found to be more effective in reducing RDC's. RDC's have been reduced to levels at or near the target of 0.03 working level under optimal ventilation conditions. Natural gas consumption with the new equipment is about 39% higher than with the original equipment. Electrical energy usage and electrical demand are respectively 50 and 44% higher with the new equipment than with the original equipment. 16 refs., 14 figs., 8 tabs

  20. Luminescent solar concentrator improvement by stimulated emission

    Science.gov (United States)

    Kaysir, Md Rejvi; Fleming, Simon; MacQueen, Rowan W.; Schmidt, Timothy W.; Argyros, Alexander

    2015-12-01

    Luminescent solar concentrators (LSCs) offer the prospect of reducing the cost of solar energy, and are a promising candidate for building integrated photovoltaic (PV) structures. However, the realization of commercially viable efficiency of LSCs is currently hindered by reabsorption losses. In this work, a method is introduced for reducing reabsorption as well as improving directional emission in LSCs by using stimulated emission. Light from a seed laser (potentially an inexpensive laser diode) passes through the entire length of the LSC panel, modifying the emission spectrum of excited dye molecules such that it is spectrally narrower, at wavelengths that minimize reabsorption, and directed by the seed laser towards a small target PV cell. A mathematical model of such a system is presented which identifies different physical parameters responsible for the power conversion efficiency and gives the net effective output power.

  1. Luminescent solar concentrators utilizing stimulated emission.

    Science.gov (United States)

    Kaysir, Md Rejvi; Fleming, Simon; MacQueen, Rowan W; Schmidt, Timothy W; Argyros, Alexander

    2016-03-21

    Luminescent solar concentrators (LSCs) are an emerging technology that aims primarily to reduce the cost of solar energy, with great potential for building integrated photovoltaic (PV) structures. However, realizing LSCs with commercially viable efficiency is currently hindered by reabsorption losses. Here, we introduce an approach to reducing reabsorption as well as improving directional emission in LSCs by using stimulated emission. Light from a seed laser (potentially an inexpensive laser diode) passes through the entire area of the LSC panel, modifying the emission spectrum of excited dye molecules such that it is spectrally narrower, at wavelengths that minimize reabsorption to allow net gain in the system, and directed towards a small PV cell. A mathematical model, taking into account thermodynamic considerations, of such a system is presented which identifies key parameters and allows evaluation in terms of net effective output power. PMID:27136870

  2. Renewable Energy Essentials: Concentrating Solar Thermal Power

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    Concentrated solar thermal power (CSP) is a re-emerging market. The Luz Company built 354 MWe of commercial plants in California, still in operations today, during 1984-1991. Activity re-started with the construction of an 11-MW plant in Spain, and a 64-MW plant in Nevada, by 2006. There are currently hundreds of MW under construction, and thousands of MW under development worldwide. Spain and the United States together represent 90% of the market. Algeria, Egypt and Morocco are building integrated solar combined cycle plants, while Australia, China, India, Iran, Israel, Italy, Jordan, Mexico, South Africa and the United Arab Emirates are finalising or considering projects. While trough technology remains the dominant technology, several important innovations took place over 2007-2009: the first commercial solar towers, the first commercial plants with multi-hour capacities, the first Linear Fresnel Reflector plants went into line.

  3. Recent advancements in ion concentration polarization.

    Science.gov (United States)

    Li, Min; Anand, Robbyn K

    2016-06-21

    In this minireview, we discuss advancements in ion concentration polarization (ICP)-based preconcentration, separation, desalination, and dielectrophoresis that have been made over the past three years. ICP as a means of controlling the distribution of the ions and electric field in a microfluidic device has rapidly expanded its areas of application. Recent advancements have focused on the development of ion-permselective materials with tunable dimensions and surface chemistry, adaptation to paper microfluidics, higher-throughput device geometries, and coupling ICP with other separation (isotachophoresis and dielectrophoresis) and fluidic (valve and droplet microfluidic) strategies. These studies have made great strides toward solving real-world problems such as low-cost and rapid analysis, accessible desalination technology, and single-cell research tools. PMID:26965754

  4. Droplet Number Concentration Value-Added Product

    Energy Technology Data Exchange (ETDEWEB)

    Riihimaki, L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McFarlane, S. [DOE ARM Climate Research Facility, Washington, DC (United States); Sivaraman, C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-06-01

    The ndrop_mfrsr value-added product (VAP) provides an estimate of the cloud droplet number concentration of overcast water clouds retrieved from cloud optical depth from the multi-filter rotating shadowband radiometer (MFRSR) instrument and liquid water path (LWP) retrieved from the microwave radiometer (MWR). When cloud layer information is available from vertically pointing lidar and radars in the Active Remote Sensing of Clouds (ARSCL) product, the VAP also provides estimates of the adiabatic LWP and an adiabatic parameter (beta) that indicates how divergent the LWP is from the adiabatic case. quality control (QC) flags (qc_drop_number_conc), an uncertainty estimate (drop_number_conc_toterr), and a cloud layer type flag (cloud_base_type) are useful indicators of the quality and accuracy of any given value of the retrieval. Examples of these major input and output variables are given in sample plots in section 6.0.

  5. Towards a flat 45%-efficient concentrator module

    International Nuclear Information System (INIS)

    The so-called CCS4FK is an ultra-flat photovoltaic system of high concentration and high efficiency, with potential to convert, ideally, the equivalent of a 45% of direct solar radiation into electricity by optimizing the usage of sun spectrum and by collecting part of the diffuse radiation, as a flat plate does. LPI has recently finished a design based on this concept and is now developing a prototype based on this technology, thanks to the support of FUNDACION REPSOL-Fondo de Emprendedores, which promotes entrepreneur projects in different areas linked to energy. This works shows some details of the actual design and preliminary potential performance expected, according to accurate spectral simulations

  6. Andrology laboratory review: Evaluation of sperm concentration.

    Science.gov (United States)

    Brito, Leonardo F C; Althouse, Gary C; Aurich, Christine; Chenoweth, Peter J; Eilts, Bruce E; Love, Charles C; Luvoni, Gaia C; Mitchell, Jere R; Peter, Augustine T; Pugh, David G; Waberski, Dagmar

    2016-06-01

    This article is the result of the work of the andrology task-force of the Association of Applied Animal Andrology, American College of Theriogenologists, European College of Animal Reproduction, Society for Theriogenology, and National Association of Animal Breeders. It is intended to serve as a comprehensive reference on methods to evaluate sperm concentration and to contribute to the adoption of best practices in veterinary andrology laboratories. The information covered in the article includes sample preparation and the use of manual counts, spectrophotometers, computer-assisted semen analysis, NucleoCounter, and flow cytometry. Emphasis is given to the principles of the methods and equipment, performing the evaluation, and common mistakes and/or pitfalls. In addition, the precision and accuracy of the different methods are also discussed. PMID:27045626

  7. A study of radon indoor concentration

    International Nuclear Information System (INIS)

    It was realized a study of radon concentration in houses of Mexico City and in a laboratory of the Nuclear Centre of Salazar, State of Mexico. The radon determination in air was realized with solid nuclear track detectors and with Honeywell and Alpha guard automatic equipment. The results show that the majority of houses have values under 148 Bq/m3 obtaining some housings with upper values located in the Lomas zone. A study in smokers houses and another of controls showed very similar distributions. It was studied the day time fluctuations finding that radon increases considerably during the dawn. Some upper values obtained in a laboratory of the Nuclear Centre were remedied with ventilation. (Author)

  8. Mineralogical characterization of uranium yellow cake concentrates

    International Nuclear Information System (INIS)

    Uranium yellow cake concentrates have been analyzed and characterized mineralogically by means of differential thermal analysis, X-ray diffraction, infrared spectra and wet chemical methods. On the basis of mineralogical methods of characterization, the following four major structural types of yellow cake may be classified: Uranyl Hydroxide Hydrate, UO2(OH)2nH2O; Basic Uranyl Sulfate Hydrate, (UO2)x(SO4)y(OH)s(x-y).nH2O; Sodium Para-Uranate, Na5U7O24 and Uranyl Peroxide Hydrate, UO4.nH2O. In this paper conditions of yellow cake preparation and characterization are described, along with discussion of significance of structural types to the physical and chemical properties of yellow cake production

  9. Prediction Methods for Blood Glucose Concentration

    DEFF Research Database (Denmark)

    Freckmann et al. discusses performance metrics used to characterize the accuracy of continuous glucose measurement devices. This topic is highly relevant for prediction models since many of them rely on the data given by the continuous sensors which are previously calibrated with blood glucose meter...... on the net effect of meals on the blood glucose concentration. By assuming that all major unexplained glycemic excursions can be vi Preface attributed to oral glucose ingestion, a meal vector is estimated which significantly improves the mathematical model. Results are shown on three patients during...... intrasubject variability by using the concept of interval pre-dictions. Instead of predicting a single blood glucose value in the future, a whole solution envelope is determined. With the presented theory it can be guaranteed that the real value is always inside of the envelope and moreover the envelope...

  10. Assays for Determination of Protein Concentration.

    Science.gov (United States)

    Olson, Bradley J S C

    2016-01-01

    Biochemical analysis of proteins relies on accurate quantification of protein concentration. Detailed in this appendix are some commonly used methods for protein analysis, e.g., Lowry, Bradford, bicinchoninic acid (BCA), UV spectroscopic, and 3-(4-carboxybenzoyl)quinoline-2-carboxaldehyde (CBQCA) assays. The primary focus of this report is assay selection, emphasizing sample and buffer compatibility. The fundamentals of generating protein assay standard curves and of data processing are considered, as are high-throughput adaptations of the more commonly used protein assays. Also included is a rapid, inexpensive, and reliable BCA assay of total protein in SDS-PAGE sample buffer that is used for equal loading of SDS-PAGE gels. © 2016 by John Wiley & Sons, Inc. PMID:27248579

  11. Tracking accuracy assessment for concentrator photovoltaic systems

    Science.gov (United States)

    Norton, Matthew S. H.; Anstey, Ben; Bentley, Roger W.; Georghiou, George E.

    2010-10-01

    The accuracy to which a concentrator photovoltaic (CPV) system can track the sun is an important parameter that influences a number of measurements that indicate the performance efficiency of the system. This paper presents work carried out into determining the tracking accuracy of a CPV system, and illustrates the steps involved in gaining an understanding of the tracking accuracy. A Trac-Stat SL1 accuracy monitor has been used in the determination of pointing accuracy and has been integrated into the outdoor CPV module test facility at the Photovoltaic Technology Laboratories in Nicosia, Cyprus. Results from this work are provided to demonstrate how important performance indicators may be presented, and how the reliability of results is improved through the deployment of such accuracy monitors. Finally, recommendations on the use of such sensors are provided as a means to improve the interpretation of real outdoor performance.

  12. Modular off-axis solar concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Plesniak, Adam P; Hall, John C

    2015-01-27

    A solar concentrator including a housing defining a vertical axis and including a receiving wall connected to a reflecting wall to define an internal volume and an opening into the internal volume, wherein the reflecting wall defines at least one primary optical element, and wherein at least a portion of the reflecting wall includes a layer of reflective material, the housing further including a cover connected to the receiving wall and the reflecting wall to seal the opening, and at least one receiver mounted on the receiving wall such that a vertical axis of the receiver is disposed at a non-zero angle relative to the vertical axis of the housing, the receiver including at least one photovoltaic cell.

  13. Electrostatic interactions in concentrated protein solutions

    CERN Document Server

    Mishra, Shradha

    2013-01-01

    We present an approximate method for calculating the electrostatic free energy of concentrated protein solutions. Our method uses a cell model and accounts for both the coulomb energy and the entropic cost of Donnan salt partitioning. The former term is calculated by linearizing the Poisson-Boltzmann equation around a nonzero average potential, while the second term is calculated using a jellium approximation that is empirically modified to reproduce the dilute solution limit. When combined with a short-ranged binding interaction, calculated using the mean spherical approximation, our model reproduces osmotic pressure measurements of bovine serum albumin solutions. We also use our free energy to calculate the salt-dependent shift in the critical temperature of lysozyme solutions and show why the predicted salt partitioning between the dilute and dense phases has proven experimentally elusive.

  14. Measuring protein concentration with entangled photons

    CERN Document Server

    Crespi, Andrea; Matthews, Jonathan C F; Politi, Alberto; Neal, Chris R; Ramponi, Roberta; Osellame, Roberto; O'Brien, Jeremy L

    2011-01-01

    Optical interferometry is amongst the most sensitive techniques for precision measurement. By increasing the light intensity a more precise measurement can usually be made. However, in some applications the sample is light sensitive. By using entangled states of light the same precision can be achieved with less exposure of the sample. This concept has been demonstrated in measurements of fixed, known optical components. Here we use two-photon entangled states to measure the concentration of the blood protein bovine serum albumin (BSA) in an aqueous buffer solution. We use an opto-fluidic device that couples a waveguide interferometer with a microfluidic channel. These results point the way to practical applications of quantum metrology to light sensitive samples.

  15. Clinical Use of Factor XIII Concentrates.

    Science.gov (United States)

    Lassila, Riitta

    2016-06-01

    Factor (F) XIII deficiency is a congenital rare bleeding disorder (RBD), with an estimated prevalence of 1 in 1 to 2 million individuals, and more than 1,200 patients have been diagnosed to date. In newborns, umbilical cord bleeding is typical, and later in life during trauma, surgery and even spontaneously prolonged bleeds, reproduction, and delivery complications occur frequently without appropriate replacement therapy. Also, an acquired form of FXIII deficiency may occur via massive bleeds or neutralizing antibodies. In the inherited form of FXIII deficiency, prophylaxis with FXIII concentrate is administered to prevent the very high risk of intracranial bleeds, the incidence being close to 30%. Laboratory diagnosis of FXIII deficiency is based on measuring plasma FXIII antigen and activity, and it is claimed that FXIII activity of around 5 IU/dL would suffice to protect from bleeds. However, at the low levels of detection, most FXIII methods are inaccurate, and quality controls and collaboration with reference laboratories are important to improve the accuracy of low-level FXIII measurements. The trough target for prophylaxis should be set to 10 to 20 IU/dL, which is achievable by administration of 25 to 35 IU/kg every 4 to 6 weeks. However, general risk factors influencing hemostasis should be carefully evaluated, including anemia and hypertension. Fibrin cross-linking by FXIII is of major importance and red cells bind to fibrin partially via platelets and FXIII to promote clot strength. Physiologically, platelets and macrophages contain FXIII providing cellular support; thus, the patients may benefit from platelet transfusion during problematic bleeds. Plasma-derived and recently a recombinant FXIII concentrate are available; however, the latter has mainly anecdotal data regarding management of bleeds and surgery, and its access is limited due to the high cost. The international registry RBD database, (RBDD) continues to gain cumulative knowledge, and

  16. Development of a commercial photovoltaic concentrator module

    Energy Technology Data Exchange (ETDEWEB)

    Saifee, S.T.; Hutchison, G. [Solar Kinetics, Inc., Dallas, TX (United States)

    1992-09-01

    The ojective of this work was to develop the design and prototype of a commercial high-concentration photovoltaic (PV) module. The design is for a 282-sun point-focus concentrating module. Most of the components, subassemblies, and design features incorporate simplifications and ease of manufacturing. The Solar Kinetics, Inc. (SKI) module is designed to incorporate high-efficiency, single-crystal silicon PV cells. The housing is made with aluminum laminated for voltage stand-off and simultaneously providing high thermal conductivity. The Fresnel lens injection molded by American Optical (AO) as singles. The cell assembly consists of a copper heat spreader, a photovoltaic cell soldered, a top and bottom contact, and a reflective secondary optical element (SOE). The cell assemblies passed all of the initial electrical characterization and high-potential tests. Under environmental cycling, the only bond that failed was the PV cell-to-heat spreader interface. The other components (top contact, bottom contact, SOE) passed all the environmental cycling tests. The cell assemblies were designed to be mounted onto the receiver section with a thermally conductive RTV. This geometry was subjected to environmental testing. There was no delamination of this bond nor was there electrical breakdown when the assemblies were subjected to the hi-pot test. A mock module was fabricated for environmental evaluation. This module was subjected to the humidity/freeze cycling to assess the performance of the lens mounting design. This module was also subjected to the rain test after the humidity/freeze cycling and checked for water leaks. The lens showed small displacement from its original position after the environmental cycling. One tablespoon of water did collect inside the module.

  17. DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

    Energy Technology Data Exchange (ETDEWEB)

    P. Bernot

    2005-07-13

    The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this activity is to predict dissolved concentrations or solubility limits for elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) relevant to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are provided in the form of tabulated functions with pH and log fCO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. Even though selection of an appropriate set of radionuclides documented in Radionuclide Screening (BSC 2002 [DIRS 160059]) includes actinium, transport of Ac is not modeled in the total system performance assessment for the license application (TSPA-LA) model because of its extremely short half-life. Actinium dose is calculated in the TSPA-LA by assuming secular equilibrium with {sup 231}Pa (Section 6.10); therefore, Ac is not analyzed in this report. The output data from this report are fundamental inputs for TSPA-LA used to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for the actinides discussed in this report. These models cover broad ranges of environmental conditions so they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or

  18. Dynamics of concentrated ferrofluid with labelled particles

    International Nuclear Information System (INIS)

    In the study of ferrofluid dynamics the separation of self and pair correlation is the essential problem at both intermediate and high concentrations of the magnetic phase. The neutron spin-echo (NSE) total scattering function St(q, t)=βSp(q, t)+(1-β)Ss(q, t) contains both contributions, where the parameter β=σp/(σp+σs) depends on the corresponding cross sections σs,p. To distinguish these different kinds of dynamics we eliminated one of them by using a mixture of magnetic particles with different scattering amplitudes and concentrations. The NSE experiments (LLB, CE-Saclay) at momentum transfer q1∼0.4 nm ∼1/Dp (Dp is the particle diameter) and q2∼0.7 nm1/Dp have been carried out for these opposite situations. The functions Sp(q, t), Ss(q, t), from these data behave quite differently. The autocorrelations reveal a stretched relaxation at low q: Ss(q, t)=exp[-q2Γ(t)/2], where Γ(t)=2Dtα is the squared particle displacement, the exponent α=0.5±0.1 at q1, and α=0.8±0.1 at q2. The magnitude α<1 indicates the strong influence of dipole forces on the motion of a particle. It resembles the segmental relaxation in a polymer chain. On the other hand, the pair correlations show the oscillations (period∼40 ns, amplitude∼1 nm) mixed with diffusion. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  19. Diverse microbial species survive high ammonia concentrations

    Science.gov (United States)

    Kelly, Laura C.; Cockell, Charles S.; Summers, Stephen

    2012-04-01

    Planetary protection regulations are in place to control the contamination of planets and moons with terrestrial micro-organisms in order to avoid jeopardizing future scientific investigations relating to the search for life. One environmental chemical factor of relevance in extraterrestrial environments, specifically in the moons of the outer solar system, is ammonia (NH3). Ammonia is known to be highly toxic to micro-organisms and may disrupt proton motive force, interfere with cellular redox reactions or cause an increase of cell pH. To test the survival potential of terrestrial micro-organisms exposed to such cold, ammonia-rich environments, and to judge whether current planetary protection regulations are sufficient, soil samples were exposed to concentrations of NH3 from 5 to 35% (v/v) at -80°C and room temperature for periods up to 11 months. Following exposure to 35% NH3, diverse spore-forming taxa survived, including representatives of the Firmicutes (Bacillus, Sporosarcina, Viridibacillus, Paenibacillus, Staphylococcus and Brevibacillus) and Actinobacteria (Streptomyces). Non-spore forming organisms also survived, including Proteobacteria (Pseudomonas) and Actinobacteria (Arthrobacter) that are known to have environmentally resistant resting states. Clostridium spp. were isolated from the exposed soil under anaerobic culture. High NH3 was shown to cause a reduction in viability of spores over time, but spore morphology was not visibly altered. In addition to its implications for planetary protection, these data show that a large number of bacteria, potentially including spore-forming pathogens, but also environmentally resistant non-spore-formers, can survive high ammonia concentrations.

  20. Intraindividual stability of hair cortisol concentrations.

    Science.gov (United States)

    Stalder, Tobias; Steudte, Susann; Miller, Robert; Skoluda, Nadine; Dettenborn, Lucia; Kirschbaum, Clemens

    2012-05-01

    The analysis of cortisol in human hair constitutes a promising method for the retrospective assessment of cumulative cortisol secretion over extended periods of time. An implicit assumption underlying the use of this method is that in the absence of major life changes hair cortisol concentrations show a high level of intraindividual stability, i.e. single hair cortisol assessments exhibit considerable trait-specificity and are only to a smaller extent influenced by state-dependent factors. Here, we present data from two independent studies examining patterns of intraindividual stability in hair cortisol levels. In study I, 45 participants were examined at two sampling points carried out one year apart from each other. In study II, 64 individuals provided data at three sampling points which occurred at two-month intervals. In both studies, at each time point hair was sampled and relevant psychosocial and hair-related variables were assessed. Results of both studies consistently revealed strong test-retest associations for repeated hair cortisol measurements ('r's between 0.68 and 0.79, 'p's <0.0001). Findings of structural equation modelling applied to data of study II showed that single hair cortisol assessments comprise a strong trait component, explaining between 59 and 82% of variance, and are only to a lesser extent influenced by state-related factors. Only inconsistent evidence for covariation of changes in hair cortisol concentrations and simultaneous changes in perceived stress or other relevant variables was seen across the two studies. The current findings suggest a considerable degree of intraindividual stability in hair cortisol levels which highlights the utility of this method for obtaining trait estimates of long-term cortisol secretion in psychoneuroendocrinological research. PMID:21917384

  1. Measurement of radon activity concentration in buildings

    International Nuclear Information System (INIS)

    Radon exposure, along with medical-related exposure, is the leading source of exposure to ionising radiation for the French population. Measurement campaigns are done in the action plan, drawn up by the French nuclear safety authority (ASN), in cooperation with the French directorate for housing, town planning and countryside (DHUP), the French radiation protection and nuclear safety institute (IRSN), the French health monitoring institute (InVS) and the French scientific and technical centre for construction (CSTB). The review of 2005-2008 measurement campaign shows that of the 7356 buildings screened, 84.8% had activity concentration levels below the 400 Bq/m3 action level. For the other buildings (15.2%), action will be required to reduce human exposure to radon, possibly including building renovation/redevelopment work. In the 1999-2002 measurement campaign,12% of the 13,000 buildings screened had a radon activity concentration level higher than 400 Bq/m3. In addition, the ASN and the French general directorate of labour (DGT) are continuing to work on drawing up regulations for occupational risk management. The second national health and environment plan (PNSE 2) was published on 26 June 2009. It follows on from the actions initiated in PNSE 1, a document provided for under the Public Health Act dated 9 August 2004 and under the French 'Grenelle' environmental agreements. On the basis of guidelines laid out in PNSE 2, a radon action plan for 2009-2012 will be drawn up, enabling some of the actions to be continued, particularly in the fields of new building projects and dwellings. (author)

  2. Toxicity Data to Determine Refrigerant Concentration Limits

    Energy Technology Data Exchange (ETDEWEB)

    Calm, James M.

    2000-09-30

    This report reviews toxicity data, identifies sources for them, and presents resulting exposure limits for refrigerants for consideration by qualified parties in developing safety guides, standards, codes, and regulations. It outlines a method to calculate an acute toxicity exposure limit (ATEL) and from it a recommended refrigerant concentration limit (RCL) for emergency exposures. The report focuses on acute toxicity with particular attention to lethality, cardiac sensitization, anesthetic and central nervous system effects, and other escape-impairing effects. It addresses R-11, R-12, R-22, R-23, R-113, R-114, R-116, R-123, R-124, R-125, R-134, R-134a, R-E134, R-141b, R-142b, R-143a, R-152a, R-218, R-227ea, R-236fa, R-245ca, R-245fa, R-290, R-500, R-502, R-600a, R-717, and R-744. It summarizes additional data for R-14, R-115, R-170 (ethane), R-C318, R-600 (n-butane), and R-1270 (propylene) to enable calculation of limits for blends incorporating them. The report summarizes the data a nd related safety information, including classifications and flammability data. It also presents a series of tables with proposed ATEL and RCL concentrations-in dimensionless form and the latter also in both metric (SI) and inch-pound (IP) units of measure-for both the cited refrigerants and 66 zerotropic and azeotropic blends. They include common refrigerants, such as R-404A, R-407C, R-410A, and R-507A, as well as others in commercial or developmental status. Appendices provide profiles for the cited single-compound refrigerants and for R-500 and R-502 as well as narrative toxicity summaries for common refrigerants. The report includes an extensive set of references.

  3. Denitrification of reprocessing concentrates of middle activity

    International Nuclear Information System (INIS)

    In order to reduce the releases from the Marcoule reprocessing plant, the treatment of liquid waste of low and medium level activity by chemical precipitation has been replaced by evaporation. Due to the high nitrate content of liquid waste, encapsulation in bitumen of the concentrate leads to considerable volumes of waste to be stored in geological formation. For safety reasons and so as to reduce the volume of waste, the elimination of the nitrates is essential: there exist various means: electrodialysis, biological denitration, chemical denitration and incineration. In view of the very high sodium nitrate content of the concentrate, electrodialysis and biological denitration were discarded. Preliminary experiments carried out at Cadarache led us to choose calcination in a fluidized bed rather than chemical denitration using a mixture of formic and phosphoric acids. Tests on a low temperature mock-up have determined the choice of an injection system that operates with liquid under pressure with the nozzle situated inside the fluidized layer. So as to avoid the vaporization of the liquid within, the injection piping also requires a cooling system using air, with a double casing. Under these conditions, liquid can be injected into the reactor without encountering any special difficulty: no plugging of the nozzle, a regular flow and liquid, stable temperature and pressure levels from top to bottom of the reactor. Differential thermogravimetric and heat analyses have led to the following conclusions: - at temperatures below 500 deg C, the nitric acid, then the aluminium nitrate decompose and produce alumina. -between approximately 570 deg C and 630 deg C, the sodium nitrate in turn decomposes and reacts with the alumina to produce a sodium aluminate. -finally, these tests enabled a reaction kinetics low of sodium nitrate decomposition in the temperature range of 500 deg C to 1000 deg C to be established. (author)

  4. DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

    International Nuclear Information System (INIS)

    The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this activity is to predict dissolved concentrations or solubility limits for elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) relevant to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are provided in the form of tabulated functions with pH and log fCO2 as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. Even though selection of an appropriate set of radionuclides documented in Radionuclide Screening (BSC 2002 [DIRS 160059]) includes actinium, transport of Ac is not modeled in the total system performance assessment for the license application (TSPA-LA) model because of its extremely short half-life. Actinium dose is calculated in the TSPA-LA by assuming secular equilibrium with 231Pa (Section 6.10); therefore, Ac is not analyzed in this report. The output data from this report are fundamental inputs for TSPA-LA used to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for the actinides discussed in this report. These models cover broad ranges of environmental conditions so they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or otherwise

  5. Molecular basis of high viscosity in concentrated antibody solutions: Strategies for high concentration drug product development.

    Science.gov (United States)

    Tomar, Dheeraj S; Kumar, Sandeep; Singh, Satish K; Goswami, Sumit; Li, Li

    2016-01-01

    Effective translation of breakthrough discoveries into innovative products in the clinic requires proactive mitigation or elimination of several drug development challenges. These challenges can vary depending upon the type of drug molecule. In the case of therapeutic antibody candidates, a commonly encountered challenge is high viscosity of the concentrated antibody solutions. Concentration-dependent viscosity behaviors of mAbs and other biologic entities may depend on pairwise and higher-order intermolecular interactions, non-native aggregation, and concentration-dependent fluctuations of various antibody regions. This article reviews our current understanding of molecular origins of viscosity behaviors of antibody solutions. We discuss general strategies and guidelines to select low viscosity candidates or optimize lead candidates for lower viscosity at early drug discovery stages. Moreover, strategies for formulation optimization and excipient design are also presented for candidates already in advanced product development stages. Potential future directions for research in this field are also explored. PMID:26736022

  6. Lime, agent to uranium concentration; La chaux comme agent de concentration de l'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Mouret, P.; Le Bris, J.; Kremer, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Gautier, R. [Etablissement Kuhlmann, Service d' Etudes et de Pilotages Industriels (France)

    1958-07-01

    Choice of the process according to health requirements. Description of the process: dissolution of uranium by sulfuric leaching of ores, precipitation of uranium by lime, re-dissolution of the concentrate with nitric ions, purification by T.B.P. finally resulting in pure uranyl nitrate solution containing 400 g/litre. (author)Fren. [French] Les raisons du choix du procede en fonction des imperatifs d'hygiene, sont exposees ainsi que le procede qui consiste en une dissolution de l'uranium des minerais par lixiviation sulfurique, precipitation de l'uranium par la chaux et redissolution du concentre en presence d'ions nitriques, purification par le T.B.P. et obtention d'un concentre final de nitrate d'uranyle pur a 400 g/litre. (auteur)

  7. Intercomparison of passive microwave sea ice concentration retrievals over the high-concentration Arctic sea ice

    DEFF Research Database (Denmark)

    andersen, susanne; Tonboe, R.; Kaleschke, L.; Heygster, G.; Pedersen, Leif Toudal

    [1] Measurements of sea ice concentration from the Special Sensor Microwave Imager (SSM/I) using seven different algorithms are compared to ship observations, sea ice divergence estimates from the Radarsat Geophysical Processor System, and ice and water surface type classification of 59 wide...... trusted subset of the SAR scenes across the central Arctic allow the separation of the ice concentration uncertainty due to emissivity variations and sensor noise from other error sources during the winter of 2003-2004. Depending on the algorithm, error standard deviations from 2.5 to 5.0% are found with...... sensor noise between 1.3 and 1.8%. This is in accord with variability estimated from analysis of SSM/I time series. Algorithms, which primarily use 85 GHz information, consistently give the best agreement with both SAR ice concentrations and ship observations. Although the 85 GHz information is more...

  8. Preovulatory progesterone concentration associates significantly to follicle number and LH concentration but not to pregnancy rate

    DEFF Research Database (Denmark)

    Yding Andersen, Claus; Bungum, Leif; Nyboe Andersen, Anders;

    2011-01-01

    Using data from a large prospective randomized controlled trial that evaluated the effect of recombinant LH (rLH)co-administration for ovarian stimulation, the present study assessed whether progesterone concentration on the day of human chorionic gonadotrophin (HCG) administration was associated...... with pregnancy outcome. Progesterone concentration was measured on stimulation day 1 and on the day of HCG administration in 475 patients who underwent IVF/intracytoplasmic sperm injection treatment following ovarian stimulation with gonadotrophin-releasing hormone (GnRH) agonist and recombinant FSH...

  9. DOES INDUSTRIAL CONCENTRATION RAISE PRODUCTIVITY IN FOOD INDUSTRIES?

    OpenAIRE

    Gopinath, Munisamy; Pick, Daniel H.; Li, Yonghai

    2002-01-01

    This manuscript investigates the productivity-industrial concentration relationship in U.S. food industries. We identify a critical level of industrial concentration beyond which its relationship with productivity growth becomes negative. The welfare effects of an increase in concentration - productivity growth and deadweight loss- are computed. Welfare loss from increasing concentration is substantially offset by gains from productivity growth.

  10. 21 CFR 146.150 - Canned concentrated orange juice.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Canned concentrated orange juice. 146.150 Section... Fruit Juices and Beverages § 146.150 Canned concentrated orange juice. (a) Canned concentrated orange... labeling of ingredients prescribed for frozen concentrated orange juice by § 146.146, except that it is...

  11. Radionuclide Activity Concentrations in Spas of Argentina

    International Nuclear Information System (INIS)

    Geothermal waters have been used on a large scale for bathing, drinking and medical purposes. These waters often have a very high mineral content because solubility increases with temperature. Ground waters are in close contact with soil and rocks containing radium. Once formed by decay from radium, radon gas (Rn-222) may diffuse through rocks pores and geological discontinuities and may dissolve in these waters. Radon and other natural radionuclides are transported to the surface where radon can easily diffuse into the atmosphere. Then it may be possible to find out significant radon levels at places like geothermal spas. In this work the most important natural radionuclide activity concentrations in different thermal spas of Argentina were measured to characterize waters and to evaluate the exposure of workers and members of the public. Three passive methods were used to measure radon in air. One of them is an screening method based on the radon adsorption on activated charcoal. The other two methods are time integrated ones, CR-39 or Makrofol tracks detectors, which can be exposed between two and three months. To characterize waters other natural radionuclides have been also measured. Uranium concentration was measured by fluorimetry. Ra-226 and Pb-210 measurements were performed by radiochemical methods and liquid scintillation. The results obtained were compared with the guidelines values recommended by WHO and EPA for drinking waters and, in the case of radon in air, the results were compared with values established by BSS-115. In order to assess worker doses, the higher value measured for radon in air and real scenario data were taken into account. Moreover, in situ dose rate measurements were also performed and then compared with natural background values. In relation with water characterization, almost all values obtained for the geothermal waters analyzed were below the corresponding guidance levels. Taking into account the highest value measured of radon

  12. Concentrated flow erosion processes under planned fire

    Science.gov (United States)

    Langhans, Christoph; Noske, Phil; Van Der Sant, Rene; Lane, Patrick; Sheridan, Gary

    2016-04-01

    The role of wildfire in accelerating erosion rates for a certain period after fire has been well documented. Much less information is available on the erosion rates and processes after planned fires that typically burn at much lower intensity. Observational evidence, and some studies in southern and southeastern Australia suggest that erosion after planned fire can be significant if rainfall intensities exceed critical intensities and durations. Understanding erosion processes and rates under these event conditions is of critical importance for planning of burn locations away from critical human assets such as water supplies and infrastructure. We conducted concentrated flow experiments with the purpose to understand what critical conditions are required for significant erosion to occur on planned burn hillslopes. Concentrated flow runon was applied on pre-wetted, unbounded plots of 10 m at rates of 0.5, 1, 1.5 and 2 L/s, with three replicates for each rates applied at 1m distance of each other. The experiments were carried out at three sites within one burn perimeter with different burn severities ranging from low to high, with two replicates at each site. Runon was applied until an apparent steady state in runoff was reached at the lower plot boundary, which was typically between 0.7 and 2.5 minutes. The experiments were filmed and erosion depth was measured by survey methods at 1m intervals. Soil surface properties, including potential sediment trapping objects were measured and surveyed near the plots. We found that fire severity increased plot scale average erosion depth significantly even as experiments were typically much shorter on the high severity plots. Unit stream power was a good predictor for average erosion depth. Uncontrolled for variations in soil surface properties explained process behaviour: finer, ash rich surface material was much less likely to be trapped by fallen, charred branches and litter than coarser, ash-depleted material. Furthermore

  13. Concentration and flux of bioaerosol and environmental factors

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The concentration and flux transportation of bioaerosol are analyzed using the data observed in Nanjing in July 1998. Some results are obtained: (i) the concentration and flux transportation of bioaerosol vary periodically with the cycle of the solar radiation and atmospheric turbulent intensity, (ii) The bioaerosol concentration is affected by both the bioaerosol flux transportation and the environmental factors. The bacterial concentration is obviously affected by the solar radiation while the fungi concentration is significantly affected by temperature.

  14. Rotary Apparatus Concentrates And Separates Micro-Organisms

    Science.gov (United States)

    Noever, David A.

    1992-01-01

    Apparatus concentrates and separates swimming micro-organisms of different species into concentric rings in fluid. Fluid containing high concentration of desired species removed by use of small scoop placed into fluid at radius of one of rings formed by that species. Micro-organisms concentrated into concentric rings by combined dynamic effects of upward and horizontal components of swimming, rotation of dish, gravitation, and viscosity.

  15. Extraction and concentration of phenolic compounds from water and sediment

    Science.gov (United States)

    Goldberg, M.C.; Weiner, Eugene R.

    1980-01-01

    Continuous liquid-liquid extractors are used to concentrate phenols at the ??g l-1 level from water into dichloromethane; this is followed by Kuderna-Danish evaporative concentration and gas chromatography. The procedure requires 5 h for 18 l of sample water. Overall concentration factors around 1000 are obtained. Overall concentration efficiencies vary from 23.1 to 87.1%. Concentration efficiencies determined by a batch method suitable for sediments range from 18.9 to 73.8%. ?? 1980.

  16. Increased PIVKA-II concentrations in patients with cystic fibrosis.

    OpenAIRE

    de Montalembert, M; Lenoir, G; Saint-Raymond, A.; Rey, J.; Lefrère, J J

    1992-01-01

    Serum vitamin K concentrations and prothrombin induced by absence of vitamin K (PIVK-II) concentrations were assayed in 43 patients with cystic fibrosis. Twenty nine showed a normal PIVKA-II and vitamin K concentrations; 14 showed an increased PIVKA-II concentration, in one of whom serum vitamin K was decreased. Although their vitamin K concentrations were normal, some patients with cystic fibrosis still had an increased PIVKA-II. There was a significant correlation between PIVKA-II concentra...

  17. Intercomparison of aerosol instruments: number concentration

    International Nuclear Information System (INIS)

    An intercomparison of aerosol instruments conducted February 23-27, 1981, at the Environmental Measurements Laboratory (EML) focused on five instruments: the Pollak and TSI condensation nucleus counters; the Active Scattering Aerosol Spectrometer (ASAS-X); and two aerosol electrometers. Test aerosols of sodium chloride and ammonium fluorescein generated by nebulization/electrostatic classification were used to obtain 195 lines of comparison data. Concentrations measured by the ASAS-X and the TSI aerosol electrometer averaged respectively 1.388 and 1.581 times that measured by the Pollak. These ratios were very stable during the week and there was little effect of particle size or material. Most other comparisons were equally stable. However, a review of past work at EML and elsewhere led to the disturbing conclusion that these ratios may change from year to year, or from season to season. A filter sample was taken from microscopy, concurrent with readings from the ASAS-X and the TSI condensation nucleus counters. In this sample, the two instruments differed by 20%. Within its 20% uncertainty, the filter result matched both the TSI and ASAS-X readings

  18. Fallout Concentration Various Environmental Samples in Indonesia

    International Nuclear Information System (INIS)

    The testing of nuclear weapons have been carried out by the advanced countries, such as United States, Russian Federation, United Kingdom, France, China, India and Pakistan, since about 1945 until 1998. Nuclear weapons tests were conducted at various locations, on and above the earth's surface or underground or on and under the ocean's surface. Nuclear explosions caused the radionuclides of fission product, such as 131l, 89Sr, 90Sr, 134Cs, 137Cs, and 239Pu released to the atmospheric layer. In the atmospheric layer, the long-lived radionuclides, i.e, 90Sr dan 137Cs will be distributed into the environment as the fallout radionuclides, and deposited in the various environmental samples (soil, water, and biota). In general, at several locations in Indonesia the 90Sr and 137Cs in the various environmental samples still can be detected. The data of measurement results of 90Sr and 137Cs concentrations were generally lower than that from some countries in the northern hemisphere. (author)

  19. Solar thermal and concentrated solar power barometer

    International Nuclear Information System (INIS)

    The European concentrated solar power plant market is steeling itself for tough time ahead. The number of projects under construction is a pittance compared with 2012 that was an excellent year for installations (an additional 802.5 MW of capacity recorded). This drop is the result of the moratorium on renewable energy power plants introduced by the Spanish government. The European solar thermal market is hardly any more encouraging . EurObserv'ER holds that it slipped for the fourth year in a row (it dropped 5.5% between 2011 and 2012). The newly-installed solar thermal collector surface area in the EU now stands at 3.4 million m2, far short of its 2008 installation record of 4.6 million m2. The EU's solar thermal base to date at the end of 2012 is 29.6 GWth with 2.4 GWth installed during the year 2012. This article gives tables gathering the figures of the production for every European country for 2012 and describes the market and the general trend for every EU member

  20. Concentric scheme of monkey auditory cortex

    Science.gov (United States)

    Kosaki, Hiroko; Saunders, Richard C.; Mishkin, Mortimer

    2003-04-01

    The cytoarchitecture of the rhesus monkey's auditory cortex was examined using immunocytochemical staining with parvalbumin, calbindin-D28K, and SMI32, as well as staining for cytochrome oxidase (CO). The results suggest that Kaas and Hackett's scheme of the auditory cortices can be extended to include five concentric rings surrounding an inner core. The inner core, containing areas A1 and R, is the most densely stained with parvalbumin and CO and can be separated on the basis of laminar patterns of SMI32 staining into lateral and medial subdivisions. From the inner core to the fifth (outermost) ring, parvalbumin staining gradually decreases and calbindin staining gradually increases. The first ring corresponds to Kaas and Hackett's auditory belt, and the second, to their parabelt. SMI32 staining revealed a clear border between these two. Rings 2 through 5 extend laterally into the dorsal bank of the superior temporal sulcus. The results also suggest that the rostral tip of the outermost ring adjoins the rostroventral part of the insula (area Pro) and the temporal pole, while the caudal tip adjoins the ventral part of area 7a.

  1. Concentration limits from a technical standpoint

    International Nuclear Information System (INIS)

    The discharge of hazardous substances in an industrial waste water can cause a number of negative effects in the sewers and in the treatment plants. The most important of these effects are: - Corrosion of sewers, pumping stations and treatment plants. Risk for explosion and fire. - Disturbances in the physical, biological and chemical treatment processes. - Disturbances in the stabilization and dewatering of sludge and increase of toxic components of the sludge leading to reduced usability in agriculture. - Detrimental impact on the ecosystem of the receiving streams and lakes. - Disturbances of the working environment for the operation staff, health risks, nuisance and inconvenience. Swedish requirements governing the discharge of hazardous substances from industries into municipal sewerage systems have been put together in a list of limit values published by the Swedish Water and Sewage Works Association, VAV. The list specifies the maximum concentrations that can be accepted at the connection point between the industrial plant and municipal network with regard to the effect on the sewers, and at the inlet to the treatment plant with regard to the treatment processes

  2. Peanut cake concentrations in massai grass silage

    Directory of Open Access Journals (Sweden)

    Luciano S. Lima

    2013-03-01

    Full Text Available Objective. This experiment was conducted to evaluate the best concentration of peanut cake in the ensiling of massai grass of the chemical-bromatological composition, fermentative characteristics, forage value rate, ingestion estimates, and digestibility of dry matter in the silage. Materials and methods. The experiment was carried out at the Experimental Farm of São Gonçalo dos Campos at the Federal University of Bahia, Brazil. The treatments consisted of massai grass that was cut at 40 days and dehydrated, in addition to 0%, 8%, 16%, and 24% peanut cake in the fresh matter and treatment without cake. The material was compressed in experimental silos (7 liter that were opened after 76 days. Results. The addition of 8-24% peanut cake improved the silage’s chemical-bromatological parameters, increased the dry matter and non-fiber carbohydrates and reduced the fibrous components. There was a linear increase in the estimated values of digestibility and the ingestion of dry matter depending on the levels of peanut cake in the silage. There was an improvement in the fermentative characteristics, with a quadratic effect positive for levels of ammoniacal nitrogen. The forage value rate increased linearly with the inclusion of peanut cake. Conclusions. The inclusion of up to 24% peanut cake during ensiling of massai grass increases the nutritive value of silage and improves fermentation characteristics.

  3. Concentration of uranium in seawater by flotation

    International Nuclear Information System (INIS)

    A method has been developed for the concentration of uranium in seawater by precipitation flotation-carbonate extraction-ion flotation. Uranium in seawater was coprecipitated with hydrated iron (III) oxide by adjusting the pH to 5.5 after addition of 1.0 x 10-3 mol/l of iron (III) and agitating for 1 hr, and the precipitate was floated with 1.0 x 10-5 mol/l of sodium oleate and 5.0 x 10-5 mol/l of sodium lauryl sulfate by bubbling nitrogen through the seawater for 15 min. Uranium was extracted from the precipitate scum at the yield of 89 % with 100 ml of 1.8 % of ammonium carbonate solution by agitating for 2 hr, and floated with 1.2 x 10-3 mol/l of cetylpyridinium chloride by bubbling nitrogen through the extract diluted 5-fold for 30 min in the recovery of about 100 %. The fairly selective recovery of uranium was obtained from 4 l of seawater at the yield of 87 % throughout the entire process. (author)

  4. Intercomparison of soil radon concentration measurements

    International Nuclear Information System (INIS)

    In October last year the first intercomparison of measurements of the soil radon concentrations between various laboratories in Slovakia was realised. The organisation of this intercomparison was conducted by the Slovak Legal Metrology in Banska Bystrica together with the Slovak National Accreditation Service in Bratislava (SNAS). The scientific guarantee of the exercise was the State metrological Centre for radon quantities, which is working at the Research base of Slovak Medical University in Bratislava. The main objective of the intercomparison was to verify the correctness of the methods for the soil radon measurements of the authorised laboratories for radon volume activities in soil air. The intercomparison (signed as SLM ILC 3/03) was performed as a 'circular' metrology comparison, in accordance with a methodical directive MSA 0117-98, published by SNAS. Six laboratories were participating on the intercomparison and there have been two stages of the work one in the radon chamber of the State metrological Centre and the second in the real field conditions. The results of the exercise have confirmed the capability of the participating laboratories for licensing of their measurements as authorised laboratories. The achieved accuracy, as well as the level of technical skill of the participants are a significant step for quality assurance improvement and for optimisation of the soil radon measurements. (authors)

  5. Capacity Value of Concentrating Solar Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Madaeni, S. H.; Sioshansi, R.; Denholm, P.

    2011-06-01

    This study estimates the capacity value of a concentrating solar power (CSP) plant at a variety of locations within the western United States. This is done by optimizing the operation of the CSP plant and by using the effective load carrying capability (ELCC) metric, which is a standard reliability-based capacity value estimation technique. Although the ELCC metric is the most accurate estimation technique, we show that a simpler capacity-factor-based approximation method can closely estimate the ELCC value. Without storage, the capacity value of CSP plants varies widely depending on the year and solar multiple. The average capacity value of plants evaluated ranged from 45%?90% with a solar multiple range of 1.0-1.5. When introducing thermal energy storage (TES), the capacity value of the CSP plant is more difficult to estimate since one must account for energy in storage. We apply a capacity-factor-based technique under two different market settings: an energy-only market and an energy and capacity market. Our results show that adding TES to a CSP plant can increase its capacity value significantly at all of the locations. Adding a single hour of TES significantly increases the capacity value above the no-TES case, and with four hours of storage or more, the average capacity value at all locations exceeds 90%.

  6. Luminescent Solar Concentrators in the Algal Industry

    Science.gov (United States)

    Hellier, Katie; Corrado, Carley; Carter, Sue; Detweiler, Angela; Bebout, Leslie

    2013-03-01

    Today's industry for renewable energy sources and highly efficient energy management systems is rapidly increasing. Development of increased efficiency Luminescent Solar Concentrators (LSCs) has brought about new applications for commercial interests, including greenhouses for agricultural crops. This project is taking first steps to explore the potential of LSCs to enhance production and reduce costs for algae and cyanobacteria used in biofuels and nutraceuticals. This pilot phase uses LSC filtered light for algal growth trials in greenhouses and laboratory experiments, creating specific wavelength combinations to determine effects of discrete solar light regimes on algal growth and the reduction of heating and water loss in the system. Enhancing the optimal spectra for specific algae will not only increase production, but has the potential to lessen contamination of large scale production due to competition from other algae and bacteria. Providing LSC filtered light will reduce evaporation and heating in regions with limited water supply, while the increased energy output from photovoltaic cells will reduce costs of heating and mixing cultures, thus creating a more efficient and cost effective production system.

  7. Ammonia Solubility in High Concentration Salt Solutions

    Energy Technology Data Exchange (ETDEWEB)

    HEDENGREN, D.C.

    2000-02-01

    Solubility data for ammonia in water and various dilute solutions are abundant in the literature. However, there is a noticeable lack of ammonia solubility data for high salt, basic solutions of various mixtures of salts including those found in many of the Hanford Washington underground waste tanks. As a result, models based on solubility data for dilute salt solutions have been used to extrapolate to high salt solutions. These significant extrapolations need to be checked against actual laboratory data. Some indirect vapor measurements have been made. A more direct approach is to determine the ratio of solubility of ammonia in water to its solubility in high salt solutions. In various experiments, pairs of solutions, one of which is water and the other a high salt solution, are allowed to come to equilibrium with a common ammonia vapor pressure. The ratio of concentrations of ammonia in the two solutions is equal to the ratio of the respective ammonia solubilities (Henry's Law constants) at a given temperature. This information can then be used to refine the models that predict vapor space compositions of ammonia. Ammonia at Hanford is of concern because of its toxicity in the environment and its contribution to the flammability of vapor space gas mixtures in waste tanks.

  8. Tracking-integrated systems for concentrating photovoltaics

    Science.gov (United States)

    Apostoleris, Harry; Stefancich, Marco; Chiesa, Matteo

    2016-04-01

    Concentrating photovoltaic (CPV) systems, which use optical elements to focus light onto small-area solar cells, have the potential to minimize the costs, while improving efficiency, of photovoltaic technology. However, CPV is limited by the need to track the apparent motion of the Sun. This is typically accomplished using high-precision mechanical trackers that rotate the entire module to maintain normal light incidence. These machines are large, heavy and expensive to build and maintain, deterring commercial interest and excluding CPV from the residential market. To avoid this issue, some attention has recently been devoted to the development of tracking-integrated systems, in which tracking is performed inside the CPV module itself. This creates a compact system geometry that could be less expensive and more suitable for rooftop installation than existing CPV trackers. We review the basic tracking principles and concepts exploited in these systems, describe and categorize the existing designs, and discuss the potential impact of tracking integration on CPV cost models and commercial potential.

  9. Regulating Competing Supramolecular Interactions Using Ligand Concentration.

    Science.gov (United States)

    Teunissen, Abraham J P; Paffen, Tim F E; Ercolani, Gianfranco; de Greef, Tom F A; Meijer, E W

    2016-06-01

    The complexity of biomolecular systems inevitably leads to a degree of competition between the noncovalent interactions involved. However, the outcome of biological processes is generally very well-defined often due to the competition of these interactions. In contrast, specificity in synthetic supramolecular systems is usually based on the presence of a minimum set of alternative assembly pathways. While the latter might simplify the system, it prevents the selection of specific structures and thereby limits the adaptivity of the system. Therefore, artificial systems containing competing interactions are vital to stimulate the development of more adaptive and lifelike synthetic systems. Here, we present a detailed study on the self-assembly behavior of a C2v-symmetrical tritopic molecule, functionalized with three self-complementary ureidopyrimidinone (UPy) motifs. Due to a shorter linker connecting one of these UPys, two types of cycles with different stabilities can be formed, which subsequently dimerize intermolecularly via the third UPy. The UPy complementary 2,7-diamido-1,8-naphthyridine (NaPy) motif was gradually added to this mixture in order to examine its effect on the cycle distribution. As a result of the C2v-symmetry of the tritopic UPy, together with small differences in binding strength, the cycle ratio can be regulated by altering the concentration of NaPy. We show that this ratio can be increased to an extent where one type of cycle is formed almost exclusively. PMID:27163942

  10. Effective beam method for element concentrations

    International Nuclear Information System (INIS)

    A method to evaluate chemical element concentrations in samples by generating an effective polychromatic beam using as initial input real monochromatic beam data is presented. There is a great diversity of research being conducted at synchrotron facilities around the world and a diverse set of beamlines to accommodate this research. Time is a precious commodity at synchrotron facilities; therefore, methods that can maximize the time spent collecting data are of value. At the same time the incident radiation spectrum, necessary for some research, may not be known on a given beamline. A preliminary presentation of a method applicable to X-ray fluorescence spectrocopic analyses that overcomes the lack of information about the incident beam spectrum that addresses both of these concerns is given here. The method is equally applicable for other X-ray sources so long as local conditions are considered. It relies on replacing the polychromatic spectrum in a standard fundamental parameters analysis with a set of effective monochromatic photon beams. A beam is associated with each element and can be described by an analytical function allowing extension to elements not included in the necessary calibration measurement(s)

  11. Arterial Stiffness and Dialysis Calcium Concentration

    Directory of Open Access Journals (Sweden)

    Fabrice Mac-Way

    2011-01-01

    Full Text Available Arterial stiffness is the major determinant of isolated systolic hypertension and increased pulse pressure. Aortic stiffness is also associated with increased cardiovascular morbidity and mortality in patients with chronic kidney disease, hypertension, and general population. Hemodynamically, arterial stiffness results in earlier aortic pulse wave reflection leading to increased cardiac workload and decreased myocardial perfusion. Although the clinical consequence of aortic stiffness has been clearly established, its pathophysiology in various clinical conditions still remains poorly understood. The aim of the present paper is to review the studies that have looked at the impact of dialysis calcium concentration on arterial stiffness. Overall, the results of small short-term studies suggest that higher dialysis calcium is associated with a transient but significant increase in arterial stiffness. This calcium dependant increase in arterial stiffness is potentially explained by increased vascular smooth muscle tone of the conduit arteries and is not solely explained by changes in mean blood pressure. However, the optimal DCa remains to be determined, and long term studies are required to evaluate its impact on the progression of arterial stiffness.

  12. Ammonia Solubility in High Concentration Salt Solutions

    International Nuclear Information System (INIS)

    Solubility data for ammonia in water and various dilute solutions are abundant in the literature. However, there is a noticeable lack of ammonia solubility data for high salt, basic solutions of various mixtures of salts including those found in many of the Hanford Washington underground waste tanks. As a result, models based on solubility data for dilute salt solutions have been used to extrapolate to high salt solutions. These significant extrapolations need to be checked against actual laboratory data. Some indirect vapor measurements have been made. A more direct approach is to determine the ratio of solubility of ammonia in water to its solubility in high salt solutions. In various experiments, pairs of solutions, one of which is water and the other a high salt solution, are allowed to come to equilibrium with a common ammonia vapor pressure. The ratio of concentrations of ammonia in the two solutions is equal to the ratio of the respective ammonia solubilities (Henry's Law constants) at a given temperature. This information can then be used to refine the models that predict vapor space compositions of ammonia. Ammonia at Hanford is of concern because of its toxicity in the environment and its contribution to the flammability of vapor space gas mixtures in waste tanks

  13. Effective beam method for element concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Tolhurst, Thomas; Barbi, Mauricio, E-mail: barbi@uregina.ca [University of Regina (Canada); Tokaryk, Tim [Royal Saskatchewan Museum (Canada)

    2015-01-29

    A method to evaluate chemical element concentrations in samples by generating an effective polychromatic beam using as initial input real monochromatic beam data is presented. There is a great diversity of research being conducted at synchrotron facilities around the world and a diverse set of beamlines to accommodate this research. Time is a precious commodity at synchrotron facilities; therefore, methods that can maximize the time spent collecting data are of value. At the same time the incident radiation spectrum, necessary for some research, may not be known on a given beamline. A preliminary presentation of a method applicable to X-ray fluorescence spectrocopic analyses that overcomes the lack of information about the incident beam spectrum that addresses both of these concerns is given here. The method is equally applicable for other X-ray sources so long as local conditions are considered. It relies on replacing the polychromatic spectrum in a standard fundamental parameters analysis with a set of effective monochromatic photon beams. A beam is associated with each element and can be described by an analytical function allowing extension to elements not included in the necessary calibration measurement(s)

  14. The renal concentrating mechanism: fundamental theoretical concepts.

    Science.gov (United States)

    Stephenson, J L

    1983-05-15

    Five theoretical principles that follow from qualitative consideration of renal architecture and tubular permeabilities are proposed to explain the concentration of urine in the mammalian kidney. These are: 1) The medullary loop of the doubly folded S-shaped configuration of the nephron permits solute supplied by ascending Henle's limb (AHL) to extract water from descending Henle's limb (DHL) and collecting duct (CD). 2) The cortical loop allows the diluted AHL fluid to return to isotonicity with cortical plasma before returning to the medulla. 3) The folded vasa recta and surrounding interstitium (the central core) provide an expansion chamber for the performance of osmotic work and a mixing chamber for salt and urea. This mixing induces passive salt transport out of AHL. 4) Overall, the system acts as a solute cycling multiplier from the AHL to vascular core and the osmotically equilibrated DHL and CD. 5) The short-looped nephrons provide urea to drive salt transport out of AHL of long nephrons in the inner medulla. PMID:6840288

  15. Platelet concentration in platelet concentrates and periodontal regeneration-unscrambling the ambiguity

    Directory of Open Access Journals (Sweden)

    A Suchetha

    2015-01-01

    Full Text Available Context: Platelet-rich-plasma (PRP and Platelet-rich-fibrin (PRF are extensively used autologous platelet concentrates in periodontal regeneration, and PRF has a better efficacy as compared to PRP. The rationale for this difference has often been attributed to the difference in the structure of the fibrin matrix. However, the effect of concentration of platelets on the regenerative potential of these concentrates is obscure. Aims: The study was conducted to evaluate and compare, clinically and radiographically, the efficacy of PRF and PRP in the treatment of periodontal endosseous defects and to assess the effect of platelet concentration on periodontal regeneration. Materials and Methods: Twenty intrabony defects were selected and divided into two groups randomly by the coin toss method. Group I received PRP and Group II subjects were treated with PRF. The platelet counts in PRP and PRF were analyzed. Clinical and radiological parameters were assessed at baseline and 3, 6, and 9 months postoperatively. Statistical Analysis: Kruskal–Wallis Chi-square test, Wilcoxon signed rank test, t-test, and Spearman's rank correlation were used for statistical analysis of data. Results: There was statistically significant improvement in all the parameters in the two groups except in relation to gingival recession. There was a statistically significant difference between the platelet count in Group I and Group II (P = 0.002. Conclusion: PRP and PRF appear to have nearly comparable effects in terms of periodontal regeneration. The concentration of platelets appears to play a paradoxical role in regeneration. The regenerative potential of platelets appears to be optimal within a limited range.

  16. Colloid-Associated Radionuclide Concentration Limits: ANL

    International Nuclear Information System (INIS)

    The purpose and scope of this report is to describe the analysis of available colloidal data from waste form corrosion tests at Argonne National Laboratory (ANL) to extract characteristics of these colloids that can be used in modeling their contribution to the source term for sparingly soluble radioelements (e.g., Pu). Specifically, the focus is on developing a useful description of the following waste form colloid characteristics: (1) composition, (2) size distribution, and (3) quantification of the rate of waste form colloid generation. The composition and size distribution information are intended to support analysis of the potential transport of the sparingly soluble radionuclides associated with the waste form colloids. The rate of colloid generation is intended to support analysis of the waste form colloid-associated radionuclide concentrations. In addressing the above characteristics, available data are interpreted to address mechanisms controlling colloid formation and stability. This report was developed in accordance with the ''Technical Work Plan for Waste Form Degradation Process Model Report for SR'' (CRWMS M and O 2000). Because the end objective is to support the source term modeling we have organized the conclusions into two categories: (1) data analysis conclusions and (2) recommendations for colloid source term modeling. The second category is included to facilitate use of the conclusions from the data analysis in the abstraction of a colloid source term model. The data analyses and conclusions that are presented in this report are based on small-scale laboratory tests conducted on a limited number of waste glass compositions and spent fuel types

  17. Mercury concentration in coal - Unraveling the puzzle

    Science.gov (United States)

    Toole-O'Neil, B.; Tewalt, S.J.; Finkelman, R.B.; Akers, D.J.

    1999-01-01

    Based on data from the US Geological Survey's COALQUAL database, the mean concentration of mercury in coal is approximately 0.2 ??gg-1. Assuming the database reflects in-ground US coal resources, values for conterminous US coal areas range from 0.08 ??gg-1 for coal in the San Juan and Uinta regions to 0.22 ??gg-1 for the Gulf Coast lignites. Recalculating the COALQUAL data to an equal energy basis unadjusted for moisture differences, the Gulf Coast lignites have the highest values (36.4 lb of Hg/1012 Btu) and the Hams Fork region coal has the lowest value (4.8 lb of Hg/1012Btu). Strong indirect geochemical evidence indicates that a substantial proportion of the mercury in coal is associated with pyrite occurrence. This association of mercury and pyrite probably accounts for the removal of mercury with the pyrite by physical coal cleaning procedures. Data from the literature indicate that conventional coal cleaning removes approximately 37% of the mercury on an equal energy basis, with a range of 0% to 78%. When the average mercury reduction value is applied to in-ground mercury values from the COALQUAL database, the resulting 'cleaned' mercury values are very close to mercury in 'as-shipped' coal from the same coal bed in the same county. Applying the reduction fact or for coal cleaning to eastern US bituminous coal, reduces the mercury input load compared to lower-rank non-deaned western US coal. In the absence of analytical data on as-shipped coal, the mercury data in the COALQUAL database, adjusted for deanability where appropriate, may be used as an estimator of mercury contents of as-shipped coal. ?? 1998 Published by Elsevier Science Ltd. All rights reserved.

  18. Isothermal reduction of titanomagnetite concentrates containing coal

    Institute of Scientific and Technical Information of China (English)

    Tu Hu; Xue-wei Lü; Chen-guang Bai; Gui-bao Qiu

    2014-01-01

    The isothermal reduction of the Panzhihua titanomagnetite concentrates (PTC) briquette containing coal under argon atmosphere was investigated by thermogravimetry in an electric resistance furnace within the temperature range of 1250-1350°C. The samples reduced in argon at 1350°C for different time were examined by X-ray diffraction (XRD) analysis. Model-fitting and model-free methods were used to evaluate the apparent activation energy of the reduction reaction. It is found that the reduction rate is very fast at the early stage, and then, at a later stage, the reduction rate becomes slow and decreases gradually to the end of the reduction. It is also observed that the reduction of PTC by coal depends greatly on the temperature. At high temperatures, the reduction degree reaches high values faster and the final value achieved is higher than at low temperatures. The final phase composition of the reduced PTC-coal briquette consists in iron and fer-rous-pseudobrookite (FeTi2O5), while Fe2.75Ti0.25O4, Fe2.5Ti0.5O4, Fe2.25Ti0.75O4, ilmenite (FeTiO3) and wustite (FeO) are intermediate products. The reaction rate is controlled by the phase boundary reaction for reduction degree less than 0.2 with an apparent activation energy of about 68 kJ·mol-1 and by three-dimensional diffusion for reduction degree greater than 0.75 with an apparent activation energy of about 134 kJ·mol-1. For the reduction degree in the range of 0.2-0.75, the reaction rate is under mixed control, and the activation energy increases with the increase of the reduction degree.

  19. Treatment of radioactive wastes from uranium concentrating

    International Nuclear Information System (INIS)

    Radioactive wastes from uranium and thorium ore processing pose potential environmental and public health problems because of their radioactivity and chemical composition. The radionuclides exist in these wastes are those resulting from the uranium 238, uranium 235 and thorium 232 decay series. The most important radionuclide in U 238 decay series are uranium 234, thorium 230, radium 226 and some short lived radionuclides such as radon-222. Radium 226 is the nuclide of principal concern from the standpoint of the assessment and control of the radiological hazard associated with the wastes. Thus determination of uranium, thorium and radium concentration in wastes resulting from nuclear fuel cycle is very important because of its potential hazard. Various analytical methods such as fluorimetry, neutron activation analysis, radon emanation, spectrophotometry and spectroscopy are used for determination of these radionuclides. Uranium and thorium are separated from interfering element by ion exchange chromatography and measured by spectrophotometry method using arsenazo III and thorin as indicator. Radium is separated from interfering elements and α-emitters by coprecipitation of radium barium sulphate and measured by counting α-particles with surface barrier detector. Regarding to physical and chemical characteristic of waste being investigated, decontamination factors and treatment methods, chemical precipitation and coprecipitation procedure were carried out in this research work. By adding barium chloride, radium is separated from liquid waste and optimum condition were determined. Precipitation with lime and sodium-hydroxide were also studied and good result were obtained. The results show that by neutralization of waste by lime and sodium hydroxide more than 99.9% of activity was removed from stream. Advantage and disadvantage of each methods were studied and finally, effluent resulted from treatment were discharged after analysis with γ-spectroscopy and

  20. Cadmium and Chrome Concentrations in Human Milk

    Directory of Open Access Journals (Sweden)

    Sima Nazarpour

    2014-04-01

    Full Text Available Introduction: Nutrition of children has the highest priority in any program aimed at children's health care. Milk contaminated with various toxic elements can have adverse effects on children's health. This study aimed to determine the concentration of heavy metals including cadmium(Cd and chromium (Cr of breast feeding women’s milk in Varamin. Methods: This is a cross sectional study. In the present study, chromium and cadmium levels in milk of 100 mothers attending clinics in the city of Varamin were measured in four to eight weeks after delivery, using atomic absorption spectrometry. Results: The mean values (±SD of Cd and Cr in human milk were 5±6.9 μg/ml and 3±2.7 μg/ml respectively. Result of Linear regression showed that cadmium levels were higher in breast milk of people living close to the factory or industrial center. Also, the chromium levels were higher in the breast milk of women in cases of: Smoking by spouses, consumption of imported rice, consumption of mineral water, and living close to the factory or an industrial center. Conclusion: This study showed that the relationship of some factors such as living near a factory or an industrial center, smoking by spouse, the type of consumed rice and water, with the level of cadmium and chromium. Cadmium and chromium levels of breast milk in this study were higher than the levels of these elements mentioned in the reviewed articles and international standard. Because some variables, such as living near a factory or an industrial center, smoking by spouse, the type of consumed rice and water can affect the amount of entering elements in breast milk. Actions can be taken to reduce or eliminate these variables in order to decrease the mentioned elements in human milk.

  1. AMMONIA CONCENTRATION IN SALTSTONE HEADSPACE SUMMARY REPORT

    International Nuclear Information System (INIS)

    The Saltstone Facility Documented Safety Analysis (DSA) is under revision to accommodate changes in the Composite Lower Flammability Limit (CLFL) from the introduction of Isopar into Tank 50. Saltstone samples were prepared with an 'MCU' type salt solution spiked with ammonia. The ammonia released from the saltstone was captured and analyzed. The ammonia concentration found in the headspace of samples maintained at 95 C and 1 atm was, to 95% confidence, less than or equal to 3.9 mg/L. Tank 50 is fed by several influent streams. The salt solution from Tank 50 is pumped to the salt feed tank (SFT) in the Saltstone Production Facility (SPF). The premix materials cement, slag and fly ash are blended together prior to transfer to the grout mixer. The premix is fed to the grout mixer in the SPF and the salt solution is incorporated into the premix in the grout mixer, yielding saltstone slurry. The saltstone slurry drops into a hopper and then is pumped to the vault. The Saltstone Facility Documented Safety Analysis (DSA) is under revision to accommodate changes in the Composite Lower Flammability Limit (CLFL) from the introduction of Isopar(regsign) L into Tank 50. Waste Solidification-Engineering requested that the Savannah River National Laboratory (SRNL) perform testing to characterize the release of ammonia in curing saltstone at 95 C. The test temperature represents the maximum allowable temperature in the Saltstone Disposal Facility (SDF). Ammonia may be present in the salt solution and premix materials, or may be produced by chemical reactions when the premix and salt solution are combined. A final report (SRNS-STI-2008-00120, Rev. 0) will be issued that will cover in more depth the information presented in this report

  2. Mercury concentration in coal - unraveling the puzzle

    Energy Technology Data Exchange (ETDEWEB)

    Toole-O`Neil, B.; Tewalt, S.J.; Finkelman, R.B.; Akers, D.J. [Electric Power Research Institute, Palo Alto, CA (United States)

    1999-01-01

    Based on data from the US Geological Surveys COALQUAL database, the mean concentration of mercury in coal is approximately 0.2 {mu}g g{sup -1}. Assuming the database reflects in-ground US coal resources, values for conterminous US coal areas range from 0.08 {mu}g g{sup -1} for coal in the San Juan and Uinta regions to 0.22 {mu}g g{sup -1} for the Gulf Coast lignites. Recalculating the COALQUAL data to an equal energy basis unadjusted for moisture differences, the Gulf Coast lignites have the highest values (36.4 lb of Hg/10{sup 12} Btu) and the Hams Fork region coal has the lowest value (4.8 lb of Hg/10{sup 12} Btu). Strong indirect geochemical evidence indicates that a substantial proportion of the mercury in coal is associated with pyrite occurrence. This association of mercury and pyrite probably accounts for the removal of mercury with the pyrite by physical coal cleaning procedures. Data from the literature indicate that conventional coal cleaning removes approximately 37% of the mercury on an equal energy basis, with a range of 0% to 78%. When the average mercury reduction value is applied to in-ground mercury values from the COALQUAL database, the resulting `cleaned` mercury values are very close to mercury in `as-shipped` coal from the same coal bed in the same county. Applying the reduction factor for coal cleaning to eastern US bituminous coal, reduces the mercury input load compared to lower-rank non-cleaned western US coal. In the absence of analytical data on as-shipped coal, the mercury data in the COALQUAL database, adjusted for cleanability where appropriate, may be used as an estimator of mercury contents of as-shipped coal. 28 refs., 1 fig., 5 tabs.

  3. Concentrate composition for Automatic Milking Systems - Effect on milking frequency

    DEFF Research Database (Denmark)

    Madsen, J; Weisbjerg, Martin Riis; Hvelplund, Torben

    2010-01-01

    The purpose of this study was to investigate the potential of affecting milking frequency in an Automatic Milking System (AMS) by changing ingredient composition of the concentrate fed in the AMS. In six experiments, six experimental concentrates were tested against a Standard concentrate all...... the Standard concentrate. A marked effect was found on the number of visits of the cows in the AMS and the subsequent milk production in relation to composition of the concentrate. The composition of the concentrates also influenced the composition of the milk and the MR intake. Based on the overall...

  4. Concentration and purification of poliovirus by ultrafiltration and isopycnic centrifugation.

    Science.gov (United States)

    Guskey, L E; Wolff, D A

    1972-07-01

    A method is described by which poliovirus can be rapidly and simply concentrated by the use of a Diaflo XM-50 ultrafilter membrane. Freon-extracted ultrafilter concentrates banded in CsCl provided a 1,724-fold volumetric concentration of poliovirus. During concentration, trypsin-digested cellular material can pass through the ultrafilter membrane, thus providing a versatile means of degrading and eliminating extraneous contaminating proteins. The ultrafilter concentration system is compared with the CsCl cushion system of poliovirus concentration, and both systems are further compared by banding virus and virus capsid material in CsCl by use of isopycnic centrifugation. PMID:4341520

  5. Influence of Concentration of Vanadium in Zinc Oxide on Structural and Optical Properties with Lower Concentration

    Institute of Scientific and Technical Information of China (English)

    WANG Li-Wei; XU Zheng; MENG Li-Jian; Vasco Teixeira; SONG Shi-Geng; XU Xu-Rong

    2009-01-01

    ZnO films doped with different vanadium concentrations are deposited onto glass substrates by dc reactive magnetron sputtering using a zinc target doped with vanadium. The vanadium concentrations are examined by energy dispersive spectroscopy (EDS) and the charge state of vanadium in ZnO thin films is characterized by x-ray photoelectron spectroscopy. The results of x-ray diffraction (XRD) show that all the films have a wurtzite structure and grow mainly in the c-axis orientation. The grain size and residual stress in the deposited films are estimated by fitting the XRD results. The optical properties of the films are studied by measuring the transmittance. The optical constants (refractive index and extinction coefficient) and the film thickness are obtained by fitting the transmittance. All the results are discussed in relation with the doping of the vanadium.

  6. Millennial changes in North Atlantic oxygen concentrations

    Science.gov (United States)

    Hoogakker, B. A. A.; Thornalley, D. J. R.; Barker, S.

    2016-01-01

    Glacial-interglacial changes in bottom water oxygen concentrations [O2] in the deep northeast Atlantic have been linked to decreased ventilation relating to changes in ocean circulation and the biological pump (Hoogakker et al., 2015). In this paper we discuss seawater [O2] changes in relation to millennial climate oscillations in the North Atlantic over the last glacial cycle, using bottom water [O2] reconstructions from 2 cores: (1) MD95-2042 from the deep northeast Atlantic (Hoogakker et al., 2015) and (2) ODP (Ocean Drilling Program) Site 1055 from the intermediate northwest Atlantic. The deep northeast Atlantic core MD95-2042 shows decreased bottom water [O2] during millennial-scale cool events, with lowest bottom water [O2] of 170, 144, and 166 ± 17 µmol kg-1 during Heinrich ice rafting events H6, H4, and H1. Importantly, at intermediate depth core ODP Site 1055, bottom water [O2] was lower during parts of Marine Isotope Stage 4 and millennial cool events, with the lowest values of 179 and 194 µmol kg-1 recorded during millennial cool event C21 and a cool event following Dansgaard-Oeschger event 19. Our reconstructions agree with previous model simulations suggesting that glacial cold events may be associated with lower seawater [O2] across the North Atlantic below ˜ 1 km (Schmittner et al., 2007), although in our reconstructions the changes are less dramatic. The decreases in bottom water [O2] during North Atlantic Heinrich events and earlier cold events at the two sites can be linked to water mass changes in relation to ocean circulation changes and possibly productivity changes. At the intermediate depth site a possible strong North Atlantic Intermediate Water cell would preclude water mass changes as a cause for decreased bottom water [O2]. Instead, we propose that the lower bottom [O2] there can be linked to productivity changes through increased export of organic material from the surface ocean and its subsequent remineralization in the water column

  7. Analytical Methods for Uranium Concentration Measurements

    International Nuclear Information System (INIS)

    A survey of analytical procedures for the determination of uranium, as performed for NMM in the United States of America, is presented. Methods are outlined for the measurement of the element in a variety of materials, i.e. ores, concentrates, uranium metal, alloys, ceramics, compounds of uranium, scrap processing solutions, residues, and waste stream products. It is not intended as a complete résumé dealing with the subject, but it does offer measurement methods believed to give precise and accurate results of a high order. Because of the monetary value of the materials, and the transfer activities from one installation to another, involving payments or credits, burn-up charges, use charges, etc., it is essential that such methods are used. Methods of analysis to a large extent are dictated by the types of material to be analysed. The use of gravimetric methods are reviewed pertaining to product materials, which are generally defined as uranium metal, or compounds of the metal, such as oxides, halides, or nitrates. A pyro-hydrolysis technique is included under this heading. Non-volatile metallic impurities are determined spectroscopically, and the gravimetric results are corrected accordingly. Volumetric procedures, the ''workhorse'' methods for determining uranium, are thoroughly explored. The technique is applicable to all types of material, providing the uranium available for measurement is present in milligram quantities. Due to the valence states of uranium, reduction-oxidation schemes are particularly attractive. Dissolution problems, separation of interfering elements, reduction steps, and oxidation titrations of reduced uranium are discussed. The application of certain spectrophotometric and fluorometric procedures for analysing low-grade materials are included. Various separation steps incorporated in the procedures before the determination of uranium are reviewed. Along these lines the utilization of differential colorimetry is examined for determining

  8. Family-Concentrated Ownership in Chinese PLCs: Does Ownership Concentration Always Enhance Corporate Value?

    Directory of Open Access Journals (Sweden)

    Jin-Hui Luo

    2014-02-01

    Full Text Available In this paper we investigate the relationship between family ownership structure and corporate value across a sample of 1314 firm-year observations of China’s family publicly listed companies (PLCs, from 2004 to 2008. We find a significant inverse-U-shaped relationship between the controlling family’s ultimate cash-flow rights and corporate value; as measured by Tobin’s Q. That is, as family-ownership concentration increases, corporate value first increases and then decreases. This finding refreshes our understanding of the relationship between family-ownership concentration and corporate value in emerging economies such as found in China. We corroborate prior findings that when controlling families hold excess control over cash-flow rights, corporate value is significantly lowered, while multiple large shareholders structure is significantly associated with higher corporate value. In addition; board independence is found to significantly improve corporate value in the context of family-concentrated ownership. We also test for potential endogeneity between family ownership and corporate value and find our results to be robust.

  9. ANALYSIS OF PARTICULATE MASS CONCENTRATION, AEROSOL NUMBER CONCENTRATION AND VISIBILITY IN BEIJING

    Institute of Scientific and Technical Information of China (English)

    Fengqi Yan; Huanling Hu; Tong Yu

    2004-01-01

    Particulate mass concentration (PM10, PM2.5), aerosol number concentration (NOPC), aerosol size distribution and atmospheric visibility were simultaneously measured in Beijing in the summer and winter of 2001. From the profuse data collected, the following conclusions can be drown: (1) there are two peaks for the average diurnal variations of PM10 and NOPC in the summer, an obvious valley can be seen between 12:30 and 15:00 for their average diurnal variation in the winter; (2) there is one single peak for the average diurnal variation of atmospheric visibility in the summer,while there are two peaks in the winter; (3) PM10 and NOPC are usually smaller in the summer than those in the winter; (4)the average visibility is much lower during 00:00~09:00 in the summer than that in the winter, because of the very high relative humidity and higher concentration of the large particles (r>1.25 μm) in the summer during the period; (5) aerosol size distributions usually depend closely on season and relative humidity at the same place.

  10. Conversion of the chemical concentration of odorous mixtures into odour concentration and odour intensity: a comparison of methods

    CERN Document Server

    Wu, C; Zhao, P; Piringer, M; Schauberger, G

    2015-01-01

    Continuous odour measurements both of emissions as well as ambient concentrations are seldom realised, mainly because of their high costs. They are therefore often substituted by concentration measurements of odorous substances. Then a conversion of the chemical concentrations C (mg m-3) into odour concentrations COD (ouE m-3) and odour intensities OI is necessary. Four methods to convert the concentrations of single substances to the odour concentrations and odour intensities of an odorous mixture are investigated: (1) direct use of measured concentrations, (2) the sum of the odour activity value SOAV, (3) the sum of the odour intensities SOI, and (4) the equivalent odour concentration EOC, as a new method. The methods are evaluated with olfactometric measurements of seven substances as well as their mixtures. The results indicate that the SOI and EOC conversion methods deliver reliable values. These methods use not only the odour threshold concentration but also the slope of the Weber-Fechner law to include...

  11. Rising Background Odor Concentration Reduces Sensitivity of ON and OFF Olfactory Receptor Neurons for Changes in Concentration.

    Science.gov (United States)

    Hellwig, Maria; Tichy, Harald

    2016-01-01

    The ON and OFF ORNs on cockroach antennae optimize the detection and transfer of information about concentration increments and decrements by providing excitatory responses for both. It follows that the antagonism of the responses facilitates instantaneous evaluations of the odor plume to help the insect make tracking decisions by signaling "higher concentration than background" and "lower concentration than background". Here we analyzed the effect of the background concentration level of the odor of lemon oil on the responses of the ON and OFF ORNs to jumps and drops of that odor, respectively. Raising the background level decreases both the ON-ORN's response to concentration jumps and the OFF-ORN's response to concentration drops. Impulse frequency of the ON ORN is high when the concentration jump is large, but for a given jump, frequency tends to be higher when the background level is low. Conversely, impulse frequency of the OFF cell is high at large concentration drops, but higher still when the background level is low. Analyses of this double dependence revealed that the activity of both types of ORNs is raised more by increasing the change in concentration than by decreasing the background concentration by the same amount. This effect is greater in the OFF ORN than in the ON ORN, indicating a bias for falling concentrations. Given equal change in concentration, concentration drops evoke stronger responses in the OFF ORN than concentrations jumps in the ON ORN. This suggests that the OFF responses are used as alert information for accurately tracking. PMID:26973532

  12. Diurnal salivary cortisol concentrations in Parkinson’s disease: increased total secretion and morning cortisol concentrations

    Directory of Open Access Journals (Sweden)

    Skogar Ö

    2011-08-01

    Full Text Available Ö Skogar1,4, P-A Fall2, G Hallgren3, J Lökk4, B Bringer2, M Carlsson1, U Lennartsson3, H Sandbjork3, C-J Törnhage51Department of Geriatrics, Ryhov Hospital, Jonkoping, 2Department of Geriatrics, University Hospital, Linkoping, 3Department of Neurology, Skaraborg Hospital, Skovde, 4Institute of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, 5Department of Pediatrics, Skaraborg Hospital, Skövde, SwedenBackground: Parkinson’s disease (PD is a chronic neurodegenerative disorder. There is limited knowledge about the function of the hypothalamic-pituitary-adrenal axis in PD. The primary aim of this prospective study was to analyze diurnal salivary cortisol concentrations in patients with PD and correlate these with age, gender, body mass index (BMI, duration of PD, and pain. The secondary aim was to compare the results with a healthy reference group.Methods: Fifty-nine PD patients, 35 women and 24 men, aged 50–79 years, were recruited. The reference group comprised healthy individuals matched for age, gender, BMI, and time point for sampling. Salivary cortisol was collected at 8 am, 1 pm, and 8 pm, and 8 am the next day using cotton-based Salivette® tubes and analyzed using Spectria® Cortisol I125. A visual analog scale was used for estimation of pain.Results: The median cortisol concentration was 16.0 (5.8–30.2 nmol/L at 8 am, 5.8 (3.0–16.4 at 1 pm, 2.8 (1.6–8.0 at 8 pm, and 14.0 (7.5–28.7 at 8 am the next day. Total secretion and rate of cortisol secretion during the day (8 am–8 pm and the concentration of cortisol on the next morning were lower (12.5 nmol/L in the reference group. No significant correlations with age, gender, BMI, duration of PD, Hoehn and Yahr score, Unified Parkinson’s Disease Rating Scale III score, gait, pain, or cortisol concentrations were found.Conclusion: The neurodegenerative changes in PD does not seem to interfere with the

  13. GEOSTATISTICAL INTERPOLATION OF CHEMICAL CONCENTRATION. (R825689C037)

    Science.gov (United States)

    AbstractMeasurements of contaminant concentration at a hazardous waste site typically vary over many orders of magnitude and have highly skewed distributions. This work presents a practical methodology for the estimation of solute concentration contour maps and volume...

  14. GLUCOSE-CONCENTRATION IN SUBCUTANEOUS EXTRACELLULAR-SPACE

    NARCIS (Netherlands)

    SCHMIDT, FJ; SLUITER, WJ; SCHOONEN, AJM

    1993-01-01

    OBJECTIVE- To compare the subcutaneous glucose sensor measurements with two reference methods. Previous studies provide conflicting findings about the real glucose concentrations in subcutaneous tissue. Some suggest substantially lower concentration, whereas others measure proportionally higher gluc

  15. SEASONAL VARIATION IN PLASMA SEX STEROID CONCENTRATION IN JUVENILE ALLIGATORS

    Science.gov (United States)

    Seasonal variation in plasma sex steroid concentrations is common in mature vertebrates, and is occasionally seen in juvenile animals. In this study, we examine the seasonal pattern of sex hormone concentration in juvenile American alligators (Alligator mississippiensis) and make...

  16. Luminescent Solar Concentrators – a low cost photovoltaics alternative

    NARCIS (Netherlands)

    Sark, W.G.J.H.M. van

    2013-01-01

    The development and current status of luminescent solar concentrators is reviewed. These solar concentrators generally consist of transparent polymer sheets doped with luminescent species; presently mainly organic dye molecules are used as luminescent species, however semiconductor nanocrystals are

  17. Concentrating Solar Power Program Review 2013 (Book) (Revised)

    Energy Technology Data Exchange (ETDEWEB)

    2013-06-01

    This U.S. Department of Energy (DOE) Concentrating Solar Power Program Review Meeting booklet will be provided to attendees at the Concentrating Solar Power Review Meeting in Phoenix, Arizona on April 23-25, 2013.

  18. Performance analysis of solar cell arrays in concentrating light intensity

    Institute of Scientific and Technical Information of China (English)

    Xu Yongfeng; Li Ming; Wang Liuling; Lin Wenxian; Xiang Ming; Zhang Xinghua; Wang Yunfeng; Wei Shengxian

    2009-01-01

    tage in concentrating light intensity. The output power has a -20 W/V coefficient and so cooling fluid must be used. Both heat energy and electrical power are then obtained with a solar trough concentrating photovoltaic/thermal system.

  19. Use of a Concentration Game for Environmental Chemistry Class Review

    Science.gov (United States)

    Nowosielski, Danica A.

    2007-01-01

    The concentration game can be used as a complete class or a portion of it to help reinforce the material being presented or for review sessions. An environmental chemistry class review is presented with the use of the concentration game.

  20. Optimization of salt concentration in PEG-based crystallization solutions

    OpenAIRE

    Yamanaka, Mari; Inaka, Koji; Furubayashi, Naoki; Matsushima, Masaaki; Takahashi, Sachiko; Tanaka, Hiroaki; Sano, Satoshi; Sato, Masaru; Kobayashi, Tomoyuki; Tanaka, Tetsuo

    2010-01-01

    Although polyethylene glycol (PEG) is the most widely used precipitant in protein crystallization, the concentration of co-existing salt in the solution has not been well discussed. To determine the optimum salt concentration range, several kinds of protein were crystallized in a 30% PEG 4000 solution at various NaCl concentrations with various pH levels. It was found that, if crystallization occurred, the lowest effective salt concentration depended on the pH of the protein solution and the ...