Sample records for cassegrainian concentrators

  1. Cassegrainian concentrator solar array exploratory development module (United States)

    Patterson, R. E.; Crabtree, W. L.


    A miniaturized Cassegrainian concentrator solar array concept is under development to reduce the cost of multi-kW spacecraft solar arrays. A primary parabolic reflector directs incoming solar energy to a secondary, centrally mounted inverted hyperbolic reflector and down onto a solar cell mounted on an Mo heat spreader on a 0.25 mm thick Al heat fin. Each unit is 12.7 mm thick, which makes the concentrator assembly roughly as thick as a conventional panel. The output is 100 W/sq and 20 W/kg, considering 20% efficient Si cells at 100 suns. A tertiary light catcher is mounted around the cell to ameliorate optic errors. The primary reflector is electroformed Ni with protective and reflective coatings. The cells have back surface reflectors and a SiO antireflective coating. An optical efficiency of 80% is projected, and GaAs cells are being considered in an attempt to raise cell efficiencies to over 30%.

  2. Design, performance investigation and delivery of a miniaturized Cassegrainian concentrator solar array (United States)

    Patterson, R. E.


    A miniaturized Cassegrainian concentrator (MCC) solar array concept is being developed with the objective of significantly reducing the recurring cost of multikilowatt solar arrays. The desired cost reduction is obtained as a result of using very small high efficiency solar cells in conjunction with low-cost optics. In the MCC single element concept and panel concept, incident solar radiation is reflected from a primary parabolic reflector to a secondary hyperbolic reflector and finally to a 4-millimetr diameter solar cell. A light catcher cone is used to improve off-axis performance. An element is approximately 13-millimeters thick which permits efficient launch stowage of the concentrator system panels without complex optical component deployments or retractions. The MCC elements are packed in bays within graphite epoxy frames and are electrically connected into appropriate series-parallel circuits. A MCC single element with a 21 sq cm entrance aperture and a 20 percent efficient, 0.25 sq cm gallium arsenide solar cell has the same power output as 30-sq cm of 11-percent efficiency (at 68 C) silicon solar cells. The MCC concept provides the potential for a significant reduction in array cost due to a 99 percent reduction in required cell area and a 30 percent reduction in array area relative to planar array of equivalent power.

  3. Effects of illumination functions on the computation of gravity-dependent signal path variation models in primary focus and Cassegrainian VLBI telescopes (United States)

    Abbondanza, Claudio; Sarti, Pierguido


    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.

  4. Design requirements for high-efficiency high concentration ratio space solar cells (United States)

    Rauschenbach, H.; Patterson, R.


    A miniaturized Cassegrainian concentrator system concept was developed for low cost, multikilowatt space solar arrays. The system imposes some requirements on solar cells which are new and different from those imposed for conventional applications. The solar cells require a circular active area of approximately 4 mm in diameter. High reliability contacts are required on both front and back surfaces. The back area must be metallurgically bonded to a heat sink. The cell should be designed to achieve the highest practical efficiency at 100 AMO suns and at 80 C. The cell design must minimize losses due to nonuniform illumination intensity and nonnormal light incidence. The primary radiation concern is the omnidirectional proton environment.

  5. Tailored edge-ray concentrator for a solar furnace at the Plataforma Solar de Almeria (United States)

    Collares-Pereira, Manuel; Mendes, Joao F.; Rabl, Ari; Ries, Harald


    The use of two stage optical designs, with reasonably compact devices, is required for being close to the thermodynamic limit to optical concentration of solar collectors. In this work we will present the design and the first test results of a second stage concentrator to be added to the existing primary of the solar furnace of Plataforma Solar de Almeria (PSA), designed to improve the final concentration and to increase its working temperature. Different options have been considered, including CPC, CEC, Trumpet, Cassegrainian, and tailored edge-ray devices. For the geometry of the PSA solar furnace, the tailored edge ray comes closest to the thermodynamic limits. It also is the most suitable from a practical point of view.

  6. High-performance deployable structures for the support of high-concentration ratio solar array modules (United States)

    Mobrem, M.


    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.

  7. Low cost, high concentration ratio solar cell array for space applications (United States)

    Patterson, R. E.; Rauschenbach, H. S.; Cannady, M. D.; Whang, U. S.; Crabtree, W. L.


    A miniaturized Cassegrainian-type concentrator solar array concept for space applications is described. In-orbit cell operating temperatures near 80 C are achieved with purely passive cell cooling and a net concentration ratio of 100. A multiplicity of miniaturized, rigid solar cell concentrator subassemblies are electrically interconnected in conventional fashion and mounted into rigid frames to form concentrator solar panel assemblies approximately 14-mm thick. A plurality of such interconnected panels forms a stowable and deployable solar cell blanket. It is projected that for 20% efficient silicon cells an array of 500 kW beginning-of-life output capability, including orbiter cradle structures, can be transported by a single shuttle orbiter flight into low earth orbit. In-orbit array specific performance is calculated to be approximately 100 W/sq m and 20 W/kg, including all stowage, deployment and array figure control equipment designed for a 30-year orbital life. Higher efficiency gallium arsenide and multiple band gap solar cells will improve these performance factors correspondingly.

  8. Concentrated Ownership

    DEFF Research Database (Denmark)

    Rose, Caspar


    , 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....

  9. Concentrating Radioactivity (United States)

    Herrmann, Richard A.


    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. Cleaner concentrates

    Energy Technology Data Exchange (ETDEWEB)

    Boudechiche, S.; Hall, S. [University of Nottingham, Nottingham (United Kingdom)


    The desire for higher quality coal products in froth flotation has led to the introduction of a number of novel flotation techniques, including flotation columns, but the benefits of each in relation to the source of the slurry must be evaluated before plant is installed. It was to assess on a laboratory scale the quality of coal flotation concentrates from column flotation of fine coal (-500{mu}m) as an alternative to the traditional conventional agitated cell that this work was carried out. The column developed specifically for this purpose allowed the establishment of an approach to the examination of the flotation response of samples of UK coals (originating from Bolsover, Derbyshies; Rawdon, Leicestershire; and Bilsthorpe, Nottinghamshire). The work indicates the importance of the origin of the feed slurry, since each type of coal exhibits a different flotation response. The observations from the results described in this paper enable an assessment to be made of the merits of column flotation in fine coal treatment. 11 refs., 4 figs., 5 tabs.

  11. Performance limits of heliostat fields

    Energy Technology Data Exchange (ETDEWEB)

    Kribus, A.; Krupkin, V.; Yogev, A. [Weizmann Inst. of Science, Rehovot (Israel). Environmental Sciences and Energy Research Dept.; Spirkl, W. [Ludwig-Maximilians-Univ. Muenchen (Germany). Sektion Physik


    Geometric and thermodynamic arguments are used to derive upper limits on the performance of a solar energy collection system, consisting of an axisymmetric heliostat field, a solar tower, secondary optics and a black receiver. Performance limits on collected power, concentration, and work output are presented. Performance of tower systems with several secondary optics options is compared: tower-top Compound Parabolic Concentrator (CPC), Tailored Edge-Ray Concentrator (TERC) approximated by a cone, and Cassegrainian with ground-level CPC or Compound Elliptic Concentrator (CEC). Optimized ray tracing is used to generate the design parameters of the secondary concentrators that yield the highest optical efficiency. The results show that the tower-top Cone provides the best performance regarding both concentration and efficiency, except for very large fields. The Cassegrainian designs come in second, but become equal and even better than the Cone for large fields. The results for the Cassegrainian are sensitive to the value of the reflectivity, due to the additional reflections incurred. The choice of a CEC is better than a CPC for the terminal concentration in a Cassegrainian system, but the difference is small. The suitability of the different design options for high-temperature solar applications is discussed. The recommendations regarding optical configuration depend on field size, as well as on application-specific constraints.

  12. National Geochemical Database: Concentrate (United States)

    U.S. Geological Survey, Department of the Interior — Geochemistry of concentrates from the National Geochemical Database. Primarily inorganic elemental concentrations, most samples are from the continental US and...

  13. Photovoltaics. III - Concentrators (United States)

    Backus, C. E.


    Photovoltaic concentration systems that redirect sunlight falling on a surface to a smaller solar-cell surface concentrating the intensity of sunlight many times are examined. It is noted that solar cells for concentrating systems must be designed for low internal resistance as well as for high sunlight intensities. Two designs of silicon cells are presented that perform well at high concentrations; these are interdigitated back-contact cells and vertical multijunction cells. Attention is given to heat tapping of reemitted light.

  14. When is Concentration Beneficial?


    Liron-Espana, Carmen; Lopez, Rigoberto A.


    This paper separates market power and efficiency effects of concentration in a sample of 255 U.S. manufacturing industries and computes welfare changes from rises in concentration. The empirical findings reveal that in nearly two-third of the cases, consumers lose as efficiency gains are generally pocketed by the industries. From an aggregate welfare standpoint, concentration is found to be beneficial in nearly 70% of the cases, mostly for low and moderate levels of concentration being partic...

  15. Concentration of Hydrogen Peroxide (United States)

    Parrish, Clyde F. (Inventor)


    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.

  16. Concentrating photovoltaic solar panel (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


    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. Pollutant concentrations in placenta

    DEFF Research Database (Denmark)

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


    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...... 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...

  18. Interpreting serum risperidone concentrations. (United States)

    Boerth, Joel M; Caley, Charles F; Goethe, John W


    Risperidone is an atypical antipsychotic commonly used for treatment of schizophrenia and other psychotic disorders. Although therapeutic drug monitoring is not routine for any of the atypical antipsychotics, serum antipsychotic concentrations are measured routinely to assess treatment nonadherence. In humans, risperidone is metabolized by cytochrome P450 2D6 to 9-hydroxyrisperidone; together these constitute the active moiety. Dose-proportional increases in serum concentrations have not been reported for the parent drug, but have been reported for 9-hydroxyrisperidone and the active moiety (i.e., the combined concentrations of risperidone and 9-hydroxyrisperidone). We describe a 34-year-old Caucasian man of Sicilian descent with a history of schizophrenia, disorganized type. He was suspected to be noncompliant with his risperidone therapy. Initially, active moiety risperidone concentrations increased linearly with prescribed dosage increases. However, with continued increases, active moiety concentrations adjusted downward and remained 17-36% below anticipated levels. We propose a method for estimating target active moiety concentrations of risperidone based on dosage-a method that may be used to guide clinicians in assessing nonadherence to risperidone treatment.

  19. Photovoltaic solar concentrator

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  20. Thermal cloak-concentrator (United States)

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


    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.

  1. Hydrogen Peroxide Concentrator (United States)

    Parrish, Clyde F.


    A relatively simple and economical process and apparatus for concentrating hydrogen peroxide from aqueous solution at the point of use have been invented. The heart of the apparatus is a vessel comprising an outer shell containing tubular membranes made of a polymer that is significantly more permeable by water than by hydrogen peroxide. The aqueous solution of hydrogen peroxide to be concentrated is fed through the interstitial spaces between the tubular membranes. An initially dry sweep gas is pumped through the interiors of the tubular membranes. Water diffuses through the membranes and is carried away as water vapor mixed into the sweep gas. Because of the removal of water, the hydrogen peroxide solution flowing from the vessel at the outlet end is more concentrated than that fed into the vessel at the inlet end. The sweep gas can be air, nitrogen, or any other gas that can be conveniently supplied in dry form and does not react chemically with hydrogen peroxide.

  2. Photovoltaic solar concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Nielson, Gregory N.; Okandan, Murat; Resnick, Paul J.; Cruz-Campa, Jose Luis


    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.

  3. Vacancy Concentration in Ice

    DEFF Research Database (Denmark)

    Mogensen, O. E.; Eldrup, Morten Mostgaard


    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....

  4. Concentrated loads on concrete

    DEFF Research Database (Denmark)

    Lorenzen, Karen Grøndahl; Nielsen, Mogens Peter


    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 devel......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...

  5. Solar concentrator/absorber (United States)

    Von Tiesenhausen, G. F.


    Collector/energy converter, consisting of dual-slope optical concentrator and counterflow thermal energy absorber, is attached to multiaxis support structure. Efficient over wide range of illumination levels, device may be used to generate high temperature steam, serve as solar powered dryer, or power absorption cycle cooler.

  6. Drowning in concentrated syrup. (United States)

    Talwar, Vandana; Sood, Nishant; Verma, P K


    Drowning is one of the two leading causes of accidental death in children. Most of the cases can be attributed to fresh or salt water drowning. We report an unusual case of acute respiratory distress syndrome in a one year old child following drowning in concentrated sugar syrup, in whom timely intervention and early supportive therapy resulted in a favorable outcome.

  7. 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 describ...

  8. Scattering Solar Thermal Concentrators

    Energy Technology Data Exchange (ETDEWEB)

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


    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

  9. Concentric Split Flow Filter (United States)

    Stapleton, Thomas J. (Inventor)


    A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

  10. Electrolyte Concentrates Treat Dehydration (United States)


    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.

  11. Carbon Concentration of Austenite

    Directory of Open Access Journals (Sweden)

    Z. Ławrynowicz


    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.

  12. Concentrated Solar Thermoelectric Power

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  13. Censored correlated cytokine concentrations

    DEFF Research Database (Denmark)

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


    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...... for both homogeneous and inhomogeneous normal distributions. For skewed mixture and heavy-tailed distributions, they perform reasonably well if censoring is less than 30%. We recommend these methods to estimate GMRRs. At least one of the methods is available in Stata, R or SAS....

  14. Benchmarking concentrating photovoltaic systems (United States)

    Duerr, Fabian; Muthirayan, Buvaneshwari; Meuret, Youri; Thienpont, Hugo


    Integral to photovoltaics is the need to provide improved economic viability. To achieve this goal, photovoltaic technology has to be able to harness more light at less cost. A large variety of concentrating photovoltaic concepts has provided cause for pursuit. To obtain a detailed profitability analysis, a flexible evaluation is crucial for benchmarking the cost-performance of this variety of concentrating photovoltaic concepts. To save time and capital, a way to estimate the cost-performance of a complete solar energy system is to use computer aided modeling. In this work a benchmark tool is introduced based on a modular programming concept. The overall implementation is done in MATLAB whereas Advanced Systems Analysis Program (ASAP) is used for ray tracing calculations. This allows for a flexible and extendable structuring of all important modules, namely an advanced source modeling including time and local dependence, and an advanced optical system analysis of various optical designs to obtain an evaluation of the figure of merit. An important figure of merit: the energy yield for a given photovoltaic system at a geographical position over a specific period, can be calculated.

  15. 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.


    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

  16. Stress concentration at notches

    CERN Document Server

    Savruk, Mykhaylo P


    This book compiles solutions of linear theory of elasticity problems for isotropic and anisotropic bodies with sharp and rounded notches. It contains an overview of established and recent achievements, and presents the authors’ original solutions in the field considered with extensive discussion. The volume demonstrates through numerous, useful examples the effectiveness of singular integral equations for obtaining exact solutions of boundary problems of the theory of elasticity for bodies with cracks and notches. Incorporating analytical and numerical solutions of the problems of stress concentrations in solid bodies with crack-like defects, this volume is ideal for scientists and PhD students dealing with the problems of theory of elasticity and fracture mechanics. Stands as a modern and extensive compendium of solutions to the problems of linear theory of elasticity of isotropic and anisotropic bodies with sharp and rounded notches; Adopts a highly reader-friendly layout of tables, charts, approximation ...

  17. Concentrating solar thermal power. (United States)

    Müller-Steinhagen, Hans


    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.

  18. Conical electromagnetic radiation flux concentrator (United States)

    Miller, E. R.


    Concentrator provides method of concentrating a beam of electromagnetic radiation into a smaller beam, presenting a higher flux density. Smaller beam may be made larger by sending radiation through the device in the reverse direction.

  19. Concentration of Swiss Elite Orienteers. (United States)

    Seiler, Roland; Wetzel, Jorg


    A visual discrimination task was used to measure concentration among 43 members of Swiss national orienteering teams. Subjects were above average in the number of target objects dealt with and in duration of continuous concentration. For females only, ranking in orienteering performance was related to quality of concentration (ratio of correct to…

  20. High-efficiency solar concentrator (United States)

    Lansing, F. L.; Dorman, J.


    A new type of solar concentrator is presented using liquid lenses and simple translational tracking mechanism. The concentrator achieves a 100:1 nominal concentration ratio and is compared in performance with a flat-plate collector having two sheets of glazing and non-selective coating. The results of the thermal analysis show that higher temperatures can be obtained with the concentrator than is possible with the non-concentrator flat-plate type. Furthermore, the thermal efficiency far exceeds that of the comparative flat-plate type for all operating conditions.

  1. Low concentrator PV optics optimization (United States)

    Sharp, Leonard; Chang, Ben


    Purpose: Cost reduction is a major focus of the solar industry. Thin film technologies and concentration systems are viable ways to reducing cost, with unique strengths and weakness for both. Most of the concentrating PV work focuses on high concentration systems for reducing energy cost. Meanwhile, many believe that low concentrators provide significant cost reduction potential while addressing the mainstream PV market with a product that acts as a flat panel replacement. This paper analyzes the relative benefit of asymmetric vs. symmetric optics for low-concentrators in light of specific PV applications. Approach: Symmetric and asymmetric concentrating PV module performance is evaluated using computer simulation to determine potential value across various geographic locations and applications. The selected optic design is modeled against standard cSi flat panels and thin film to determine application fit, system level energy density and economic value. Results: While symmetric designs may seem ideal, asymmetric designs have an advantage in energy density. Both designs are assessed for aperture, optimum concentration ratio, and ideal system array configuration. Analysis of performance across climate specific effects (diffuse, direct and circumsolar) and location specific effects (sunpath) are also presented. The energy density and energy production of low concentrators provide a compelling value proposition. More significantly, the choice of optics for a low concentrating design can affect real world performance. With the goal of maximizing energy density and return on investment, this paper presents the advantages of asymmetric optic concentration and illustrates the value of this design within specific PV applications.


    Directory of Open Access Journals (Sweden)

    Sophia Nikolaevna Lyubyaschenko


    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:

  3. Market concentration and economic performance


    Sophia Nikolaevna Lyubyaschenko; Valery Ivanovich Mamonov


    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 prov...

  4. concentration

    Directory of Open Access Journals (Sweden)

    Seth F. Oppenheimer


    Full Text Available We consider a model for biochemical oxygen demand (BOD in a semi-infinite river where the BOD is prescribed by a time varying function at the left endpoint. That is, we study the problem with a time varying boundary loading. We obtain the well-posedness for the model when the boundary loading is smooth in time. We also obtain various qualitative results such as ordering, positivity, and boundedness. Of greatest interest, we show that a periodic loading function admits a unique asymptotically attracting periodic solution. For non-smooth loading functions, we obtain weak solutions. Finally, for certain special cases, we show how to obtain explicit solutions in the form of infinite series.

  5. School concentration and school travel

    NARCIS (Netherlands)

    De Boer, E.


    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

  6. Least cost cusp concentrator design

    Energy Technology Data Exchange (ETDEWEB)

    Nanda, S.K.; Mullick, S.C.; Annamalai, M.; Iyer, M.V.; Nirmala, K.A.; Venkatesh, P.; Prasad, C.R.; Subramani, C.


    Cusp concentrators require larger reflector areas, but can be designed for larger acceptance angles, allowing large mirror tolerances. Design procedures are outlined to compute the optimum combination of acceptance angle and maximum mirror slope for any required concentration ratio, taking into account the material as well as fabrication costs. The cusps are compared with the parabola.

  7. Flame Propagation Through Concentration Gradient

    Institute of Scientific and Technical Information of China (English)

    JunyaIINO; MitsuakiTANABE; 等


    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.

  8. Solar Concentrator Advanced Development Program (United States)

    Knasel, Don; Ehresman, Derik


    The Solar Concentrator Advanced Development Project has successfully designed, fabricated, and tested a full scale prototypical solar dynamic concentrator for space station applications. A Truss Hexagonal Panel reflector was selected as a viable solar concentrator concept to be used for space station applications. This concentrator utilizes a modular design approach and is flexible in attainable flux profiles and assembly techniques. The detailed design of the concentrator, which included structural, thermal and optical analysis, identified the feasibility of the design and specific technologies that were required to fabricate it. The needed surface accuracy of the reflectors surface was found to be very tight, within 5 mrad RMS slope error, and results in very close tolerances for fabrication. To meet the design requirements, a modular structure composed of hexagonal panels was used. The panels, made up of graphite epoxy box beams provided the strength, stiffness and dimensional stability needed. All initial project requirements were met or exceeded by hardware demonstration. Initial testing of structural repeatability of a seven panel portion of the concentrator was followed by assembly and testing of the full nineteen panel structure. The testing, which consisted of theodolite and optical measurements over an assembly-disassembly-reassembly cycle, demonstrated that the concentrator maintained the as-built contour and optical characteristics. The facet development effort within the project, which included developing the vapor deposited reflective facet, produced a viable design with demonstrated optical characteristics that are within the project goals.

  9. Fibrinogen concentrate in bleeding patients

    DEFF Research Database (Denmark)

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


    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...

  10. 10-kilowatt Photovoltaic Concentrator Array

    Energy Technology Data Exchange (ETDEWEB)

    Donovan, R.L.; Broadbent, S.


    Martin Marietta has designed a Photovoltaic Concentrator Array (PCA) for Sandia Laboratories, Kirtland AFB, New Mexico. The PCA is based on the use of an acrylic Fresnel lens to concentrate sunlight on high intensity solar cells. The objective of the development was to obtain economical photovoltaic power generation by replacing relatively high priced solar cells with low cost lenses. Consequently, a major task of the program was to optimize the design for minimum cost per unit power output. Major design aspects considered for optimization were the concentration ratio, size and shape of the Fresnel lens, array size and shape, structure minimization, tracking and control and the practical aspects of operation and maintenance. In addition to design of the complete array, several porototype photovoltaic concentrator module subassemblies were fabricated and delivered to Sandia for evaluation. These prototypes exceed the 9.0% efficiency requirement established for this program.

  11. Mitragynine concentrations in two fatalities. (United States)

    Domingo, Olwen; Roider, Gabriele; Stöver, Andreas; Graw, Matthias; Musshoff, Frank; Sachs, Hans; Bicker, Wolfgang


    Two cases of fatalities are reported of which the recreational use of Mitragyna speciosa ("kratom") could be confirmed. One of these cases presents with one of the highest postmortem mitragynine concentrations published to date. Our results show that even extremely high mitragynine blood concentrations following the consumption of kratom do not necessarily have to be the direct cause of death in such fatalities as a result of an acute overdose. The two cases are compared with regard to the differences in mitragynine concentrations detected and the role of mitragynine in the death of the subjects. Irrespective of the big differences in mitragynine concentrations in the postmortem blood samples, mitragynine was not the primary cause of death in either of the two cases reported here. Additionally, by rough estimation, a significant difference in ratio of mitragynine to its diastereomers in the blood and urine samples between the two cases could be seen.

  12. Generalized Entropy Concentration for Counts

    CERN Document Server

    Oikonomou, Kostas N


    We consider the phenomenon of entropy concentration under linear constraints in a discrete setting, using the "balls and bins" paradigm, but without the assumption that the number of balls allocated to the bins is known. Therefore instead of \\ frequency vectors and ordinary entropy, we have count vectors with unknown sum, and a certain generalized entropy. We show that if the constraints bound the allowable sums, this suffices for concentration to occur even in this setting. The concentration can be either in terms of deviation from the maximum generalized entropy value, or in terms of the norm of the difference from the maximum generalized entropy vector. Without any asymptotic considerations, we quantify the concentration in terms of various parameters, notably a tolerance on the constraints which ensures that they are always satisfied by an integral vector. Generalized entropy maximization is not only compatible with ordinary MaxEnt, but can also be considered an extension of it, as it allows us to address...

  13. Thermodynamic efficiency of solar concentrators. (United States)

    Shatz, Narkis; Bortz, John; Winston, Roland


    The optical thermodynamic efficiency is a comprehensive metric that takes into account all loss mechanisms associated with transferring flux from the source to the target phase space, which may include losses due to inadequate design, non-ideal materials, fabrication errors, and less than maximal concentration. We discuss consequences of Fermat's principle of geometrical optics and review étendue dilution and optical loss mechanisms associated with nonimaging concentrators. We develop an expression for the optical thermodynamic efficiency which combines the first and second laws of thermodynamics. As such, this metric is a gold standard for evaluating the performance of nonimaging concentrators. We provide examples illustrating the use of this new metric for concentrating photovoltaic systems for solar power applications, and in particular show how skewness mismatch limits the attainable optical thermodynamic efficiency.

  14. Design and development of a high-concentration photovoltaic concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Hodge, R C


    The design and development of a high concentration photovoltaic concentrator module is discussed. The design concept described herein incorporates a curved groove domed Fresnel lens, a high concentration etched multiple vertical junction (EMVJ) solar cell and a passively cooled direct-bonded copper cell mount all packaged in a plastic module. Two seven inch diameter 1200x domed Fresnel lenses were fabricated using single point diamond turning technology. Testing at both GE and Sandia confirmed optical transmission efficiencies of over 83%. Samples of the latest available EMVJ cells were mounted and installed, with a domed Fresnel lens, into a prototype module. Subsequent testing demonstrated net lens-cell efficiencies of 10 to 13%. As a result of this program, salient conclusions have been formulated as to this technology.

  15. Combined processing of lead concentrates (United States)

    Kubasov, V. L.; Paretskii, V. M.; Sidorin, G. N.; Travkin, V. F.


    A combined scheme of processing of lead concentrates with the production of pure metallic lead and the important components containing in these concentrates is considered. This scheme includes sulfating roasting of the lead concentrates and two-stage leaching of the formed cinder with the formation of a sulfate solution and lead sulfate. When transformed into a carbonate form, lead sulfate is used for the production of pure metallic lead. Silver, indium, copper, cadmium, nickel, cobalt, and other important components are separately extracted from a solution. At the last stage, zinc is extracted by either extraction followed by electrolytic extraction of a metal or the return of the forming solution of sulfuric acid to cinder leaching.

  16. Segmented holographic spectrum splitting concentrator (United States)

    Ayala, Silvana P.; Vorndran, Shelby; Wu, Yuechen; Chrysler, Benjamin; Kostuk, Raymond K.


    This paper presents a segmented parabolic concentrator employing holographic spectral filters that provide focusing and spectral bandwidth separation capability to the system. Strips of low band gap silicon photovoltaic (PV) cells are formed into a parabolic surface as shown by Holman et. al. [1]. The surface of the PV segments is covered with holographic elements formed in dichromated gelatin. The holographic elements are designed to transmit longer wavelengths to silicon cells, and to reflect short wavelength light towards a secondary collector where high-bandgap PV cells are mounted. The system can be optimized for different combinations of diffuse and direct solar illumination conditions for particular geographical locations by controlling the concentration ratio and filtering properties of the holographic elements. In addition, the reflectivity of the back contact of the silicon cells is used to increase the optical path length and light trapping. This potentially allows the use of thin film silicon for the low bandgap PV cell material. The optical design combines the focusing properties of the parabolic concentrator and the holographic element to control the concentration ratio and uniformity of the spectral distribution at the high bandgap cell location. The presentation concludes with a comparison of different spectrum splitting holographic filter materials for this application.

  17. 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...

  18. Benign concentric annular macular dystrophy

    Directory of Open Access Journals (Sweden)

    Luísa Salles de Moura Mendonça


    Full Text Available The purpose of the authors is to show clinical findings of a patient with benign concentric annular macular dystrophy, which is an unusual condition, and part of the "bull’s eye" maculopathy differential diagnosis. An ophthalmologic examination with color perception, fluorescein angiography, and ocular electrophysiology was performed.

  19. Gravimetric determination of phospholipid concentration. (United States)

    Tejera-Garcia, Roberto; Connell, Lisa; Shaw, Walter A; Kinnunen, Paavo K J


    Accurate determination of lipid concentrations is an obligatory routine in a research laboratory engaged in studies using this class of biomaterials. For phospholipids, this is frequently accomplished using the phosphate assay (Bartlett, G.R. Phosphorus Assay in Column Chromatography. J. Biol. Chem. 234, 466-468, 1959). Given the purity of the currently commercially available synthetic and isolated natural lipids, we have observed that determination of the dry weight of lipid stock solutions provides the fastest, most accurate, and generic method to assay their concentrations. The protocol described here takes advantage of the high resolution and accuracy obtained by modern weighing technology. We assayed by this technique the concentrations of a number of phosphatidylcholine samples, with different degrees of acyl chain saturation and length, and in different organic solvents. The results were compared with those from Bartlett assay, (31)P NMR, and Langmuir compression isotherms. The data obtained show that the gravimetric assay yields lipid concentrations with a resolution similar or better than obtained by the other techniques.

  20. City scale pollen concentration variability (United States)

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


    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.

  1. Radioiodine concentrated in a wetland. (United States)

    Kaplan, Daniel I; Zhang, Saijin; Roberts, Kimberly A; Schwehr, Kathy; Xu, Chen; Creeley, Danielle; Ho, Yi-Fang; Li, Hsiu-Ping; Yeager, Chris M; Santschi, Peter H


    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 (129)I 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 (129)I speciation (iodide (I(-)), iodate (IO3(-)), and organo-I). Groundwater (129)I concentrations in many locations in the wetlands (as high as 59.9 Bq L(-1)(129)I) were greatly elevated with respect to the source term (5.9 Bq L(-1)(129)I). (129)I concentration profiles in sediment cores were closely correlated to organic matter concentrations (r(2) = 0.992; n = 5). While the sediment organic matter promoted the uptake of (129)I to the wetland sediment, it also promoted the formation of a soluble organic fraction: 74% of the wetland groundwater (129)I could pass through a 1 kDa (wetlands may be highly effective at immobilizing aqueous (129)I, 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.

  2. 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


    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.

  3. Sandia concentrator array testing experiences (United States)

    Gerwin, H. J.; Rogers, C. B.; Beavis, L. C.

    An assortment of PV concentrator modules and arrays have been tested and evaluated at the Sandia outdoor test facility. These test items include actively-cooled parabolic reflector and linear Fresnel lens concentrators, and actively- and passively-cooled point focus collectors. Maximum power efficiencies were measured over a range of sunlight intensities and cell temperatures, then a linear equation relating efficiency to cell temperature and insolation was developed for each module and array by using a multiple linear regression analysis technique on the data. An evaluation of the suitability of Polyvinyl-Butyral (PVB) as a material used to laminate solar cells to glass is presented. Some general observations are made on the accuracy of tracking systems, and the maintenance of these systems.

  4. Concentrating Solar Power Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)



    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. Tactical Responses to Concentrated Artillery (United States)


    aerial artillery at General Heinz Guderian’s crossing of the Meuse in May 1940 is indicative of the operational effect of tactical concentration at the...of maneuver they wished to fight. Another former tsarist artilleryman, General Golovin , argued in a 1925 article that artillery was even more...important in maneuver warfare. According to Golovin , it is necessary in order to preserve one’s freedom to maneuver and to deny it to the enemy: "The initial

  6. Purification and concentration of alphavirus. (United States)

    Lundstrom, Kenneth


    The alphaviruses Semliki Forest virus and Sindbis virus have been used frequently as expression vectors in vitro and in vivo. Usually, these systems consist of replication-deficient vectors that require a helper vector for packaging of recombinant particles. Replication-proficient vectors have also been engineered. Alphaviral vectors can be used as nucleic-acid-based vectors (DNA and RNA) or infectious particles. High-titer viral production is achieved in alphaviruses facilitates studies in mammalian and nonmammalian cell lines, primary cells in culture, and in vivo. The strong preference for expression in neuronal cells has made alphaviruses particularly useful in neurobiological studies. Unfortunately, their strong cytotoxic effect on host cells, relatively short-term transient expression patterns, and the reasonably high cost of viral production remain drawbacks. However, novel mutant alphaviruses have showed reduced cytotoxicity and prolonged expression. Membrane proteins (which are generally difficult to express at high levels in recombinant systems) have generated high yields and facilitate applications in structural biology. Alphaviruses have also been applied in vaccine development and gene therapy. Generally, purification or concentration of alphaviruses is not necessary. However, for instance, the medium derived from baby hamster kidney cells is toxic to primary neurons in culture. Including a purification step substantially improves the survival of the transduced neurons. Viral concentration and purification may also be advantageous for in vivo studies in animal models and are mandatory for clinical applications. This protocol describes three methods for purification and concentration of alphavirus.

  7. Coupling leaching of sphalerite concentrate

    Institute of Scientific and Technical Information of China (English)

    彭鹏; 谢惠琴; 卢立柱


    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.

  8. Processing of rare earth concentrates

    Institute of Scientific and Technical Information of China (English)

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


    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.

  9. 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))


    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.

  10. Rebuilding sources of linear tracers after atmospheric concentration concentration

    Directory of Open Access Journals (Sweden)

    J.-P. Issartel


    Full Text Available The identification of widespread sources of passive tracers out of atmospheric concentration measurements has become an important challenge of modern meteorology. The paper proposes some mathematical tracks to address this reconstruction of the complex space-time geometry of the sources. The methods are based upon the use of retroplumes. The inverse problem is addressed in a deterministic non statistical frame. The information obtained by local measurements is spread by introducing the concept of illumination. The constraint that the source to be rebuilt is non negative is also addressed. The experimental source ETEX1 is rebuilt in order to evaluate an impulse response of the algorithms.

  11. Wave equation with concentrated nonlinearities


    Noja, Diego; Posilicano, Andrea


    In this paper we address the problem of wave dynamics in presence of concentrated nonlinearities. Given a vector field $V$ on an open subset of $\\CO^n$ and a discrete set $Y\\subset\\RE^3$ with $n$ elements, we define a nonlinear operator $\\Delta_{V,Y}$ on $L^2(\\RE^3)$ which coincides with the free Laplacian when restricted to regular functions vanishing at $Y$, and which reduces to the usual Laplacian with point interactions placed at $Y$ when $V$ is linear and is represented by an Hermitean m...

  12. Concentrated photovoltaics, a case study

    Directory of Open Access Journals (Sweden)

    Antonini Piergiorgio


    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.

  13. Concentrated photovoltaics, a case study (United States)

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


    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.

  14. Technology Roadmaps: Concentrating Solar Power

    Energy Technology Data Exchange (ETDEWEB)



    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.

  15. Freeze concentration of lime juice

    Directory of Open Access Journals (Sweden)

    Ampawan Tansakul


    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%.

  16. Natural convection between concentric spheres (United States)

    Garg, Vijay K.


    A finite-difference solution for steady natural convective flow in a concentric spherical annulus with isothermal walls has been obtained. The stream function-vorticity formulation of the equations of motion for the unsteady axisymmetric flow is used; interest lying in the final steady solution. Forward differences are used for the time derivatives and second-order central differences for the space derivatives. The alternating direction implicit method is used for solution of the discretization equations. Local one-dimensional grid adaptation is used to resolve the steep gradients in some regions of the flow at large Rayleigh numbers. The break-up into multi-cellular flow is found at high Rayleigh numbers for air and water, and at significantly low Rayleigh numbers for liquid metals. Excellent agreement with previous experimental and numerical data is obtained.

  17. Mercury concentration in bivalve molluscs

    Directory of Open Access Journals (Sweden)

    Szkoda Józef


    Full Text Available A total of 85 mussel samples of eight species were examined. Analysis of mercury in the freeze-dried samples was carried out by atomic absorption spectrometry method using direct mercury analyser AMA 254. The analytical procedure for determination of mercury was covered by the quality assurance programme of research and participation in national and international proficiency tests. Concentrations of total mercury in all investigated samples were found to be generally low, in the range of 0.033-0.577 mg/kg of dry weight and of 0.003-0.045 mg/kg of wet weight. The results indicate that obtained levels of mercury in bivalve molluscs are not likely to pose a risk to the health of consumers.

  18. The Rheology of Concentrated Suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Andreas Acrivos


    Research program on the rheological properties of flowing suspensions. The primary purpose of the research supported by this grant was to study the flow characteristics of concentrated suspensions of non-colloidal solid particles and thereby construct a comprehensive and robust theoretical framework for modeling such systems quantitatively. At first glance, this seemed like a modest goal, not difficult to achieve, given that such suspensions were viewed simply as Newtonian fluids with an effective viscosity equal to the product of the viscosity of the suspending fluid times a function of the particle volume fraction. But thanks to the research findings of the Principal Investigator and of his Associates, made possible by the steady and continuous support which the PI received from the DOE Office of Basic Energy Sciences, the subject is now seen to be more complicated and therefore much more interesting in that concentrated suspensions have been shown to exhibit fascinating and unique rheological properties of their own that have no counterpart in flowing Newtonian or even non-Newtonian (polymeric) fluids. In fact, it is generally acknowledged that, as the result of these investigations for which the PI received the 2001 National Medal of Science, our understanding of how suspensions behave under flow is far more detailed and comprehensive than was the case even as recently as a decade ago. Thus, given that the flow of suspensions plays a crucial role in many diverse physical processes, our work has had a major and lasting impact in a subject having both fundamental as well as practical importance.

  19. [Concentration or decline in Puebla?]. (United States)

    Cabrera Becerra, V


    Some doubts have been expressed over whether the slowing pace of urbanization suggested by the 1990 census of Mexico was an accurate reflection of changing conditions, or whether it resulted from some intentional or unintended bias. Comparison of data from succeeding censuses indicates that the growth rate of the city of Puebla declined from 6.32% in 1980 to 2.63% in 1990. This work argues that, in Puebla, a trend to deconcentration of the population within the city of Puebla during the 1980s was accompanied by rapid growth in smaller and medium sized nearby cities, resulting in increased overall concentration in Puebla's metropolitan area. The absolute population of the city of Puebla increased from 772,908 in 1980 to 1,007,170 in 1990. The central area of the state of Puebla, which surrounds the city, increased its share of the state population from 51.67% in 1980 to 52.21% in 1990. The number of places with over 5000 inhabitants in the area surrounding the city of Puebla increased from 27 in 1980 to 39 in 1990. Construction of the Puebla-Atlixco highway will undoubtedly attract growth to the area southwest of Puebla. Small cities to the east of Puebla have shown significant growth although their region remains strongly rural. The same process of deconcentration of population in Puebla and concentration in its surrounding metropolitan regions can probably also be detected in patterns of investment of public funds. The trend is likely to continue through the 1990s.

  20. Offset truss hex solar concentrator (United States)

    White, John E. (Inventor); Sturgis, James D. (Inventor); Erikson, Raymond J. (Inventor); Waligroski, Gregg A. (Inventor); Scott, Michael A. (Inventor)


    A solar energy concentrator system comprises an offset reflector structure made up of a plurality of solar energy reflector panel sections interconnected with one another to form a piecewise approximation of a portion of a (parabolic) surface of revolution rotated about a prescribed focal axis. Each panel section is comprised of a plurality of reflector facets whose reflective surfaces effectively focus reflected light to preselected surface portions of the interior sidewall of a cylindrically shaped solar energy receiver. The longitudinal axis of the receiver is tilted at an acute angle with respect to the optical axis such that the distribution of focussed solar energy over the interior surface of the solar engine is optimized for dynamic solar energy conversion. Each reflector panel section comprises a flat, hexagonally shaped truss support framework and a plurality of beam members interconnecting diametrically opposed corners of the hexagonal framework recessed within which a plurality of (spherically) contoured reflector facets is disposed. The depth of the framework and the beam members is greater than the thickness of a reflector facet such that a reflector facet may be tilted (for controlling the effective focus of its reflected light through the receiver aperture) without protruding from the panel section.

  1. Automated concentrator cell module assembly (United States)

    Olah, S.; Sampson, W.

    The performance and features of linear concentrator photovoltaic arrays fabricated partially by an automated soldering machine are detailed. Float zone Si cells were mounted in five linear modules each 1.2 m long containing 48 cells. The cell strings were made up of 4 12-cell segments encapsulated in polyvinyl butyral, with two bypass diodes for every segment. An efficiency of 16.4% was achieved at 55 C, and humidity tests showed no performance degradation or cracks in an Al3O3 coating. The automatic soldering machine comprised a ribbon feeding system, an interconnect punch die, a solar cell feeder and soldering mechanism, a ribbon separation mechanism with cut-off die and outfeed, and a program control. The machine operated with low-line voltage, compressed air, and vacuum, and the processing of the cells is outlined, including cell soldering by a point contact method with a controlled immersion heater. Standardization of cell sizes is recommended to ensure flexibility of cells which can be handled.

  2. Concentrating Solar Power. Technology Roadmap

    Energy Technology Data Exchange (ETDEWEB)



    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.

  3. Gabapentin concentrations and postmortem distribution. (United States)

    Hamm, Catherine E; Gary, Ray D; McIntyre, Iain M


    Gabapentin is a widely prescribed medication used primarily for the treatment of epilepsy and neuropathic pain. Gabapentin has a favorable adverse effect profile in therapeutic dosing with the most common reported effects being dizziness, fatigue, drowsiness, weight gain, and peripheral edema. Even with intentional self-poisonings, serious effects are generally rare. In this report, gabapentin analyses were performed on 30 postmortem cases that had peripheral blood, central blood and liver tissue. Overall the central to peripheral blood (C/P) ratio mean was 0.90±0.24 (mean±standard deviation), and a median of 0.97. The liver to peripheral blood (L/P) ratio mean was 0.68±0.26L/kg (mean±standard deviation), and a median of 0.65L/kg. An additional case, where both antemortem blood and postmortem peripheral blood specimens were available, revealed the same gabapentin concentration in both specimens. Taken together, the data presented suggests that gabapentin is unlikely to show postmortem redistribution.

  4. Summary of Dissolved Concentration Limits

    Energy Technology Data Exchange (ETDEWEB)

    Yueting Chen


    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.

  5. Solar concentrator with a toroidal relay module. (United States)

    Lin, Jhe-Syuan; Liang, Chao-Wen


    III-V multijunction solar cells require solar concentrators with a high concentration ratio to reduce per watt cost and to increase solar energy transforming efficiency. This paper discusses a novel solar concentrator design that features a high concentration ratio, high transfer efficiency, thin profile design, and a high solar acceptance angle. The optical design of the concentrator utilizes a toroidal relay module, which includes both the off-axis relay lens and field lens design in a single concentric toroidal lens shape. The optical design concept of the concentrator is discussed and the simulation results are shown. The given exemplary design has an aspect ratio of 0.24, a high averaged optical concentration ratio 1230×, a maximum efficiency of 76.8%, and the solar acceptance angle of ±0.9°.

  6. Medical Oxygen Concentrator for Microgravity Operation Project (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,...

  7. 2011 NATA - Risks and Annual Ambient Concentrations (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...

  8. Probiotic Yoghurts From Ultrafiltered Concentrated Milk


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


    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...

  9. 21 CFR 155.191 - Tomato concentrates. (United States)


    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Tomato concentrates. 155.191 Section 155.191 Food... Tomato concentrates. (a) Identity—(1) Definition. Tomato concentrates are the class of foods each of... tomato ingredients: (i) The liquid obtained from mature tomatoes of the red or reddish...

  10. 21 CFR 131.115 - Concentrated milk. (United States)


    ... 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...

  11. Solar steam generation: Steam by thermal concentration (United States)

    Shang, Wen; Deng, Tao


    The solar-driven generation of water steam at 100 °C under one sun normally requires the use of optical concentrators to provide the necessary energy flux. Now, thermal concentration is used to raise the vapour temperature to 100 °C without the need for costly optical concentrators.

  12. Effects of concentrated sunlight on organic photovoltaics

    DEFF Research Database (Denmark)

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


    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...

  13. Topaz concentrate desiliconization with ammonium bifluoride


    Andreev, V. A.; Buynovskiy, A. S.; Andreev, Artyom Andreevich; Dyachenko, Alexander Nikolaevich


    Fluoridizing agent for the process of topaz concentrate desiliconization has been selected, topaz thermodynamic potentials have been appraised, thermodynamic probabilities of fluorination reaction of topaz concentrate main constituents have been calculated. The results of studying the concentrate desiliconization process with ammonium bifluoride by the methods of thermogravimetry, RFA, microphotography are presented

  14. Heavy Metal Concentrations in Maltese Potable Water

    Directory of Open Access Journals (Sweden)

    Roberta Bugeja


    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. Metamaterial anisotropic flux concentrators and magnetic arrays

    CERN Document Server

    Bjørk, R; Bahl, C R H


    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.


    Directory of Open Access Journals (Sweden)



    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.

  17. Lubricant additive concentrate containing isomerized jojoba oil

    Energy Technology Data Exchange (ETDEWEB)

    Arndt, G.


    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.

  18. Causality Between Urban Concentration and Environmental Quality

    Directory of Open Access Journals (Sweden)

    Amin Pujiati


    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.

  19. Optimal concentration for sugar transport in plants


    Jensen, Kaare H; Savage, Jessica A; Holbrook, N. Michele


    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...

  20. Balo`s concentric sclerosis: MRI

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.J. [Department of Radiology, Chang Gung Memorial Hospital, 199 Tung Hwa North Road, Taipei (Taiwan, Province of China); Ro, L.S. [Department of Neurology, Chang Gung Memorial Hospital, Taipei (Taiwan, Province of China); Wang, L.J. [Department of Radiology, Chang Gung Memorial Hospital, 199 Tung Hwa North Road, Taipei (Taiwan, Province of China); Wong, Y.C. [Department of Radiology, Chang Gung Memorial Hospital, 199 Tung Hwa North Road, Taipei (Taiwan, Province of China)


    We report a case of Balo`s concentric sclerosis. In the past, the diagnosis was usually made post mortem. In this case, we found that CT demonstrated only low-density lesions, but not their concentric pattern. However, MRI showed a striking feature, reminiscent of histopathology of Balo`s concentric sclerosis, and played an important role in antemortem diagnosis of this rare demyelinating disease. (orig.). With 3 figs.

  1. Status of photovoltaic concentrator modules and systems

    Energy Technology Data Exchange (ETDEWEB)

    Maish, A.B.


    Several leading line- and point-focus photovoltaic concentrator system development programs are reviewed, including those by ENTECH, SEA Corporation, AMONIX, and Alpha Solarco. Concentrating collectors and trackers are gaining maturity and reaching product status as designs are made more manufacturable and reliable. Utilities are starting to take notice of this emerging technology, and several privately-funded utility installations are underway. Several advantages are offered by concentrators, including low system and capital cost and rapid production ramp-up. These are discussed along with issues generally raised concerning concentrator technology.

  2. Serum gold concentrations during treatment with auranofin. (United States)

    Van Riel, P L; Gribnau, F W; Van de Putte, L B; Arts, C W; Van Aernsbergen, A


    Serum gold concentrations were measured in rheumatoid arthritis patients during chronic treatment with the orally adsorbable gold compound auranofin. In agreement with data in the literature, the highest serum gold concentration was reached after 16 weeks of treatment with 6 mg auranofin daily. A striking finding in this study was that thereafter the serum gold concentrations did not appear to plateau but declined gradually. Statistically this resulted in a significantly lower concentration after one year as compared with week 16 (p less than 0.05, paired t-test). It is suggested that a shift from protein bound gold to cell-bound gold might be the explanation.

  3. A concentration inequality for product spaces


    Dodos, Pandelis; Kanellopoulos, Vassilis; Tyros, Konstantinos


    We prove a concentration inequality which asserts that, under some mild regularity conditions, every random variable defined on the product of sufficiently many probability spaces exhibits pseudorandom behavior.

  4. Alignment method for parabolic trough solar concentrators (United States)

    Diver, Richard B.


    A Theoretical Overlay Photographic (TOP) alignment method uses the overlay of a theoretical projected image of a perfectly aligned concentrator on a photographic image of the concentrator to align the mirror facets of a parabolic trough solar concentrator. The alignment method is practical and straightforward, and inherently aligns the mirror facets to the receiver. When integrated with clinometer measurements for which gravity and mechanical drag effects have been accounted for and which are made in a manner and location consistent with the alignment method, all of the mirrors on a common drive can be aligned and optimized for any concentrator orientation.

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

    NARCIS (Netherlands)

    Collombon MT; LER


    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

  6. Horizontally staggered lightguide solar concentrator with lateral displacement tracking for high concentration applications. (United States)

    Ma, Hongcai; Wu, Lin


    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.

  7. Phytochelatin concentrations in the equatorial Pacific (United States)

    Ahner, Beth A.; Lee, Jennifer G.; Price, Neil M.; Morel, François M. M.


    Phytochelatin, an intracellular metal-binding polypeptide synthesized in eucaryotic algae in response to metals such as Cd and Cu, was measured in particulate samples collected from the equatorial Pacific. The concentrations in these samples (normalized to total particulate chl a) were unexpectedly high compared to laboratory culture data and were on average slightly more than in coastal areas where the metal concentrations are typically much greater. In part, the high field concentrations can be explained by the low cellular concentrations of chlorophyll a resulting from very low ambient Fe, but laboratory experiments provide a possible explanation for the rest of the difference. At low concentrations of inorganic Cd (Cd'=3 pM), increasing amounts of phytochelatin were induced by decreasing Zn concentrations in the culture medium of two diatoms: Thalassiosira weissflogii, a coastal species, and T. parthenaia, an isolate from the equatorial Pacific. In all previous studies, phytochelatin production has been directly correlated with increasing metal concentrations. Decreasing Co also resulted in higher phytochelatin concentrations in T. weissflogii and Emiliania huxleyi. Replicating the field concentrations of Zn, Co, and Cd in the laboratory results in cellular concentrations (amol -1 cell) that are very similar to those estimated for the field. Contrary to the expectation that high metal concentrations in the equatorial upwelling would cause elevated phytochelatin concentrations, there was no increase in phytochelatin concentrations from 20° S to 10° N—near surface samples were roughly the same at all stations. Also, most of the depth profiles had a distinct subsurface maximum. Neither of these features is readily explained by the available Zn and Cd data. Incubations with additions of Cd and Cu performed on water sampled at four separate stations induced significantly higher concentrations of phytochelatins than those in controls in a majority of the samples

  8. 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.


    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

  9. Postmortem Femoral Blood Concentrations of Risperidone

    DEFF Research Database (Denmark)

    Linnet, Kristian; Johansen, Sys Stybe


    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 ...

  10. 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.


    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


    Institute of Scientific and Technical Information of China (English)


    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.

  12. Filterability and Sludge Concentration in Membrane Bioreactors

    NARCIS (Netherlands)

    Lousada-Ferreira, M.


    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 th

  13. Metamaterial anisotropic flux concentrators and magnetic arrays

    DEFF Research Database (Denmark)

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


    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...

  14. Stress Concentration around Holes in Anistropic Sheets

    DEFF Research Database (Denmark)

    Krenk, Steen


    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...

  15. Equilibrium bed-concentration of nonuniform sediment

    Institute of Scientific and Technical Information of China (English)


    Knowledge of the equilibrium bed-concentration is vital to mathematical modeling of the river-bed deformation associated with suspended load but previous investigations only dealt with the reference concentration of uniform sediment because of difficulties in observation of the bed-concentration. This work is a first attempt to develop a theoretical formula for the equilibrium bed-concentration of any fraction of nonuniform sediment defined at the bed-surface. The formula is based on a stochastic-mechanistic model for the exchange of nonuniform sediment near the bed, and described as a function of incipient motion probability, non-ceasing probability, pick-up probability, and the ratio of the average single-step continuous motion time to static time. Comparison of bed-concentration calculated from the proposed formula with the measured data showed satisfactory agreement, indicating the present formula can be used for solving the differential equation governing the motion of suspended load.

  16. Gentamicin concentrations in human subcutaneous tissue

    DEFF Research Database (Denmark)

    Lorentzen, Hanne; Kallehave, Finn Lasse; Kolmos, Hans Jørn Jepsen


    in human subcutaneous adipose tissue by a microdialysis technique. Seven healthy young volunteers each had four microdialysis probes placed in the fat (subcutaneous) layer of the abdominal skin. After the administration of a 240-mg gentamicin intravenous bolus, consecutive measurements of the drug......Wound infections frequently originate from the subcutaneous tissue. The effect of gentamicin in subcutaneous tissue has, however, normally been evaluated from concentrations in blood or wound fluid. The aim of the present study was to investigate the pharmacokinetic properties of gentamicin...... concentrations in serum and subcutaneous interstitial fluid were obtained simultaneously for 6 h. The tissue gentamicin concentration peaked after 10 to 30 min. The peak concentration in the tissue was 6.7 +/- 2.0 mg.liter-1 (standard deviation), equivalent to 39.1% of the peak concentration in serum. The area...

  17. Concentration inequalities for sums and martingales

    CERN Document Server

    Bercu, Bernard; Rio, Emmanuel


    The purpose of this book is to provide an overview of historical and recent results on concentration inequalities for sums of independent random variables and for martingales. The first chapter is devoted to classical asymptotic results in probability such as the strong law of large numbers and the central limit theorem. Our goal is to show that it is really interesting to make use of concentration inequalities for sums and martingales. The second chapter deals with classical concentration inequalities for sums of independent random variables such as the famous Hoeffding, Bennett, Bernstein and Talagrand inequalities. Further results and improvements are also provided such as the missing factors in those inequalities. The third chapter concerns concentration inequalities for martingales such as Azuma-Hoeffding, Freedman and De la Pena inequalities. Several extensions are also provided. The fourth chapter is devoted to applications of concentration inequalities in probability and statistics.

  18. Plasma fibronectin concentrations in morbidly obese patients

    DEFF Research Database (Denmark)

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


    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. Raised plasma...

  19. Optimal concentration for sugar transport in plants. (United States)

    Jensen, Kaare H; Savage, Jessica A; Holbrook, N Michele


    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 transport efficiency predicts optimal concentrations of 23.5 per cent (if the pressure differential driving the flow is independent of concentration) and 34.5 per cent (if the pressure is proportional to concentration). Data from more than 50 experiments (41 species) collected from the literature show an average concentration in the range from 18.2 per cent (all species) to 21.1 per cent (active loaders), suggesting that the phloem vasculature is optimized for efficient transport at constant pressure and that active phloem loading may have developed to increase transport efficiency.

  20. The concentrations of uranium in marine organisms

    Energy Technology Data Exchange (ETDEWEB)

    Matsuba, Mitsue; Ishii, Toshiaki; Nakahara, Motokazu; Nakamura, Ryoichi; Watabe, Teruhisa; Hirano, Shigeki [National Inst. of Radiological Sciences, Hitachinaka, Ibaraki (Japan). Laboratory for Radioecology


    Determination of uranium in sixty-one species of marine organisms was carried out by inductively coupled plasma mass spectrometry to obtain concentration factors and to estimate the internal radiation dose. The concentrations of uranium in soft tissues of marine animals were ranged from 0.077 to 5040 ng/g wet wt. Especially, the branchial heart of cephalopod molluscs showed the specific accumulation of uranium. The concentration factor of the branchial heart of Octopus vulgaris, which indicated the highest value, was calculated to be about 1.6 x 10{sup 3}, comparing with that (3.1 ng/ml) in coastal seawaters of Japan. The concentrations of uranium in hard tissues of marine invertebrates such as clam and sea urchin were similar to those in soft tissues. In contrast, hard tissues like bone, scale, fin, etc. of fishes showed much higher concentrations of uranium than soft tissues like muscle. The concentrations of uranium of twenty-two species of algae were ranged from 2 to 310 ng/g wet wt. Particularly, the brown alga Undaria pinnatifida showed the highest value of the uranium content in the algae and its concentration factor was calculated to be 10{sup 2}. (author)

  1. Parameterizing cloud condensation nuclei concentrations during HOPE (United States)

    Hande, Luke B.; Engler, Christa; Hoose, Corinna; Tegen, Ina


    An aerosol model was used to simulate the generation and transport of aerosols over Germany during the HD(CP)2 Observational Prototype Experiment (HOPE) field campaign of 2013. The aerosol number concentrations and size distributions were evaluated against observations, which shows satisfactory agreement in the magnitude and temporal variability of the main aerosol contributors to cloud condensation nuclei (CCN) concentrations. From the modelled aerosol number concentrations, number concentrations of CCN were calculated as a function of vertical velocity using a comprehensive aerosol activation scheme which takes into account the influence of aerosol chemical and physical properties on CCN formation. There is a large amount of spatial variability in aerosol concentrations; however the resulting CCN concentrations vary significantly less over the domain. Temporal variability is large in both aerosols and CCN. A parameterization of the CCN number concentrations is developed for use in models. The technique involves defining a number of best fit functions to capture the dependence of CCN on vertical velocity at different pressure levels. In this way, aerosol chemical and physical properties as well as thermodynamic conditions are taken into account in the new CCN parameterization. A comparison between the parameterization and the CCN estimates from the model data shows excellent agreement. This parameterization may be used in other regions and time periods with a similar aerosol load; furthermore, the technique demonstrated here may be employed in regions dominated by different aerosol species.

  2. Indoor radon concentration forecasting in South Tyrol. (United States)

    Verdi, L; Weber, A; Stoppa, G


    In this paper a modern statistical technique of multivariate analysis is applied to an indoor radon concentration data base. Several parameters are more or less significant in determining the radon concentration inside a building. The elaboration of the information available on South Tyrol makes it possible both to identify the statistically significant variables and to build up a statistical model that allows us to forecast the radon concentration in dwellings, when the values of the same variables involved are given. The results confirm the complexity of the phenomenon.

  3. Indoor characterization of reflective concentrator optics (United States)

    Schmid, Tobias; Frick, Manuel; Hornung, Thorsten; Nitz, Peter


    We report about the indoor characterization of small point focusing mirrors at Fraunhofer ISE. The goal is to determine the mean slope error of the concentrator. This is achieved by measuring the concentration distribution in the focal plane of such a mirror. We modified and expanded a test site which is used for Fresnel lens characterization [1]. A modified version of the method presented in [2] is employed to measure the concentration distribution. By comparing ray tracing simulation results of the ideal mirror to the measurement, the mean slope error can be deduced.

  4. Protein concentrate production by whey ultrafiltration

    Energy Technology Data Exchange (ETDEWEB)

    Madrid Vicente, A.; Madrid Vicente, R.


    This article describes an installation and process in which whey is ultrafiltered to give whey protein concentrate and deproteinized whey, both of which are then concentrated by evaporation and spray dried. Diagrams show the ultrafiltration plant and the complete processing line, including a line for bagging and pelletizing the dried protein concentrate (400 bags of 25 kg/hour). The Romicon fibre membranes can be cleaned by pumping the ultrafiltered liquid in the reverse direction and by closing the outlet for discharge of the deproteinized whey. The deproteinized whey powder can be used for animal feeding.

  5. Universal distortion-free entanglement concentration

    CERN Document Server

    Hayashi, M; Hayashi, Masahito; Matsumoto, Keiji


    Entanglement concentration from many copies of unknown pure states is discussed, and we propose the protocol which not only achieves entropy rate, but also produces the perfect maximally entangled state. Our protocol is induced naturally from symmetry of $n$-tensored pure state, and is optimal for all the protocols which concentrates entanglement from unknown pure states, in the sense of failure probability. In the proof of optimality, the statistical estimation theory plays a key role, for concentrated entanglement gives a natural estimate of the entropy of entanglement.

  6. Luminescent solar concentrators with fiber geometry. (United States)

    Edelenbosch, Oreane Y; Fisher, Martyn; Patrignani, Luca; van Sark, Wilfried G J H M; Chatten, Amanda J


    The potential of a fibre luminescent solar concentrator has been explored by means of both analytical and ray-tracing techniques. Coated fibres have been found to be more efficient than homogeneously doped fibres, at low absorption. For practical fibres concentration is predicted to be linear with fibre length. A 1 m long, radius 1 mm, fibre LSC doped with Lumogen Red 305 is predicted to concentrate the AM1.5 g spectrum up to 1100 nm at normal incidence by ~35 x. The collection efficiency under diffuse and direct irradiance in London has been analysed showing that, even under clear sky conditions, in winter the diffuse contribution equals the direct.

  7. Water concentrations in mantle peridotite minerals (United States)

    Warren, J. M.; Hauri, E. H.


    The concentration and distribution of volatiles in the mantle is important for constraining many key properties, including melting systematics at ridges and subduction zones. We present measurements of water concentrations in nominally anhydrous minerals from abyssal, orogenic and xenolith peridotites. Analyses of fresh and altered samples from a variety of locations are used to assess the extent to which mineral water concentrations reflect primary mantle compositions, versus diffusive loss and/or hydration due to secondary processes. Water concentrations were measured in olivine (Ol), orthopyroxene (Opx) and clinopyroxene (Cpx) by ion microprobe, using mineral specific standards and monitoring background concentrations by analysis of synthetic forsterite. Analytical reproducibility, based on 11 repeat analyses of an Ol grain, is 10%, while background H2O levels varied from 7-19 ppm. Samples include xenoliths from Pali Aike, Samoa and Spitsbergen, along with unusually fresh oceanic peridotites from the Gakkel Ridge and the Tonga Trench. In addition, samples were analyzed from the Southwest Indian Ridge (SWIR) and the Josephine Peridotite, both of which have moderate degrees of alteration. In olivine, water concentrations are Pali Aike xenoliths, which have water concentrations of 16-33 ppm. On average, peridotite Opx have 187 ppm and Cpx have 474 ppm. Pyroxenite veins from the Southwest Indian Ridge have systematically lower concentrations, with an average of 12 ppm in Opx and 55 ppm in Cpx. Water partition coefficients for Opx/Ol have an average value of 28 and Cpx/Ol of 57, significantly higher than previous estimates (e.g., Hirth and Kohlstedt, 1996). Excluding the pyroxenites, the average Cpx/Opx partition coefficient is 2, in agreement with published estimates. This suggests that Cpx and Opx preserve mantle water concentrations, whereas Ol has undergone hydrogen loss. Mineral rims have water concentrations that are within error of core concentrations. The

  8. 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


    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.

  9. Advancing Concentrating Solar Power Research (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)


    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.

  10. Modular Distributed Concentrator for Solar Furnace Project (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...

  11. Concentrating solar collector-performance tests (United States)


    Report summarizes test results from evaluation of concentrating solar collector thermal performance, from transient behavior, and incident-of-angle behavior. Tests were conducted using National Bureau of Standards recommedations and specifications.

  12. Fibrinogen concentrate for bleeding - a systematic review

    DEFF Research Database (Denmark)

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


    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...

  13. Concentration for noncommutative polynomials in random matrices



    We present a concentration inequality for linear functionals of noncommutative polynomials in random matrices. Our hypotheses cover most standard ensembles, including Gaussian matrices, matrices with independent uniformly bounded entries and unitary or orthogonal matrices.

  14. Production of high concentrations of yeast

    Energy Technology Data Exchange (ETDEWEB)


    A microbe is aerobically cultured using O/sub 2/ or a gas rich in O/sub 2/. The grown cells are washed, concentrated and a portion of the cells used as a seed culture. Thus, Saccharomyces cerevisiae (bakers' yeast) was cultured in a jar fermentor by flow down system maintaining the dissolved O/sub 2/ at 2-5 mg/L; volume of the initial medium containing 30% glucose was 350 mL and the initial washed cell concentration was 50 g dry cells/L. After 12 hours of cultivation, the volume of the medium increased to 750 mL and the cell concentration rose to 102 g dry cells/L; the yield was 49% with respect to glucose. The cells were washed and the cultivation was repeated by use of the washed cells; cell concentration reached 105 g dry cells/L.

  15. Chimistry and concentration of solar radiation

    Energy Technology Data Exchange (ETDEWEB)

    Vialaron, A.


    Some data concerning solar radiation and chemical thermodynamics are reviewed, taking into account technological considerations related to industrial reactors. Finally, the advantage of thermal or thermochemical solar devices working with concentrated fluxes is shown.

  16. Arctic and Southern Ocean Sea Ice Concentrations (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...

  17. Concentration phenomena in the semilinear parabolic equation

    Institute of Scientific and Technical Information of China (English)



    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→∞.

  18. Radon concentration measurements in bituminous coal mines. (United States)

    Fisne, Abdullah; Okten, Gündüz; Celebi, Nilgün


    Radon measurements were carried out in Kozlu, Karadon and Uzülmez 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.

  19. Forecasting residual herbicide concentrations in soil (United States)

    McGrath, Gavan; Scanlan, Craig; van Zwieten, Lukas; Rose, Mick; Rose, Terry


    High concentrations of herbicides remaining in soil at the time of planting can adversely impact agricultural production and lead to off-site impacts in streams and groundwater. Being able to forecast the likelihood of residual concentrations at specific times in the future offers the potential to improve environmental and economic outcomes. Here we develop a solution for the full transient probability density function for herbicide concentrations in soil as a function of rainfall variability. Quasi-analytical solutions that account for rainfall seasonality are also demonstrated. In addition, new rapid and relatively cost-effective bioassays to quantify herbicide concentrations in near real-time, offers opportunities for data assimilation approaches to improve forecast risks.

  20. High-dimensional entanglement concentration of twisted photon pairs High-dimensional entanglement concentration (United States)

    Chen, L. X.; Wu, Q. P.


    Recently, Dada et al. reported on the experimental entanglement concentration and violation of generalized Bell inequalities with orbital angular momentum (OAM) [Nat. Phys. 7, 677 (2011)]. Here we demonstrate that the high-dimensional entanglement concentration can be performed in arbitrary OAM subspaces with selectivity. Instead of violating the generalized Bell inequalities, the working principle of present entanglement concentration is visualized by the biphoton OAM Klyshko picture, and its good performance is confirmed and quantified through the experimental Shannon dimensionalities after concentration.

  1. Plasma catecholamine concentrations associated with cerebral vasospasm. (United States)

    Loach, A B; Benedict, C R


    Plasma concentrations of adrenaline and noradrenaline were measured sequentially over the immediate post-operative period following clipping of an intracranial aneurysm in 11 patients. Those patients who developed local cerebral vasospasm showed a sustained rise in plasma catecholamines, particularly noradrenaline, whilst those patients who developed generalised cerebral vasospasm showed early peaks of very high concentrations of adrenaline and noradrenaline which preceded radiological evidence of generalized vasospam.

  2. Concentration of a Cassegrain solar furnace (United States)

    Cobble, M. H.


    A solar furnace comprising a paraboloidal mirror for tracking the sun and a hyperboloidal reflector having one focus in common with the paraboloid is analyzed to determine the geometric concentration of the system. A numerical ray-trace analysis was carried out to study various geometrical configurations of the two reflectors. In particular, the geometric concentration is calculated for the case when the line joining the foci of the hyperboloid and the axis of revolution of the paraboloid are not coincident.

  3. Influence of emulsifier concentration on nanoemulsion gelation. (United States)

    Erramreddy, Vivek Vardhan; Ghosh, Supratim


    Nanoemulsion gels are a new class of soft materials that manifest stronger elasticity even at lower dispersed phase volume fraction. In this work, gelation in 40 wt % canola oil-in-water nanoemulsions was investigated as a function of emulsifier type (anionic sodium dodecyl sulfate (SDS) or nonionic Tween 20) and concentration. It was observed that the liquid nanoemulsions transformed into viscoelastic gels at a specific concentration range of SDS, whereas no gelation was observed for Tween 20. The apparent viscosity, yield stress, and storage modulus of the nanogels increased with SDS concentration until 15 times critical micelle concentration (CMC), thereafter decreased steadily as the gelation weakened beginning 20 CMC. Three regimes of colloidal interactions in the presence of emulsifier were proposed. (1) Repulsive gelation: at low SDS concentration (0.5-2 times CMC) the repulsive charge cloud around the nanodroplets acted as interfacial shell layer that significantly increased the effective volume fraction of the dispersed phase (ϕ(eff)). When ϕ(eff) became comparable to the volume fraction required for maximal random jamming, nanoemulsions formed elastic gels. (2) Attractive gelation: as the SDS concentration increased to 5-15 times CMC, ϕ(eff) dropped due to charge screening by more counterions from SDS, but depletion attractions generated by micelles in the continuous phase led to extensive droplet aggregation which immobilized the continuous phase leading to stronger gel formation. (3) Decline in gelation due to oscillatory structural forces (OSF): at very high SDS concentration (20-30 time CMC), structural forces were manifested due to the layered-structuring of excess micelles in the interdroplet regions resulting in loss of droplet aggregation. Tween 20 nanoemulsions, on the other hand, did not show repulsive gelation due to lack of charge cloud, while weak depletion attraction and early commencement of OSF regime leading to liquid-like behavior at

  4. Individual variability in human tibia lead concentration.


    Todd, A. C.; Parsons, P J; Tang, S.; Moshier, E L


    Our aims in this study were to determine proximal-distal variability in adult human tibia lead concentration via electrothermal atomization atomic absorption spectrometry (ETAAS) and to determine whether there were any differences between core and surface tibia lead concentrations. We analyzed duplicate core and surface tibia samples for lead at multiple proximal-distal sections on 10 adult human cadaver legs. Dried bone samples were digested in nitric acid using microwave-assisted heating, a...

  5. China Resumes Processing Trade of Copper Concentrate

    Institute of Scientific and Technical Information of China (English)


    <正>On December 31,2008,China’s Ministry of Commerce and General Administration of Cus- toms issued its year-2008 No.121 announce- ment,saying it will adjust the forbidden cate- gory of processing trade,which includes non- ferrous metal products such as copper concen- trate,nickel concentrate,cobalt concentrate, refined copper,nickel and nickel alloy.The above products will be exempt from being for- bidden to process starting from Feb.1,2009.

  6. Mercury Concentration in Environmental Samples of Malaysia


    SAKAMOTO, Hayao; Ichikawa, Toshihiro; TOMIYASU, Takashi; SATO, Masanori


    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...

  7. Producing a highly concentrated coal suspension

    Energy Technology Data Exchange (ETDEWEB)

    Mokudzu, K.; Atsudzima, T.; Kiyedzuka, Y.


    Coal from wet and dry grinding is loaded into a mixer with a mixer arm with the acquisition of a highly concentrated suspension. Foamers (for instance, alkylbenzolsulfonate) and foam stabilizers (for instance diethanolamide of lauric acid) are added in a ratio of 10 to (2 to 5). The high fluidity of the suspension is maintained by injecting air into the suspension and an 80 percent concentration of the suspension is achieved.

  8. Concentrated Photo Voltaics (CPV: a case study

    Directory of Open Access Journals (Sweden)

    Centro S.


    Full Text Available Concentrated PhotoVoltaic (CPV, among green energy solutions, nowadays has the ambition to reach grid-parity without subside. CPV substitutes large areas of expensive semiconductor solar cells, with concentrating optics made of cheap materials. Moreover the cells that are suitable for CPV exhibits an unprecedented efficiency and their technology is progressing every year. A case study project, TwinFocus®, will be presented in detail.

  9. Landownership concentration and the expansion of education



    This paper studies the effect of landownership concentration on school enrollment for nineteenth-century Prussia. Prussia is an interesting laboratory given its decentralized educational system and the presence of heterogeneous agricultural institutions. We find that landownership concentration, a proxy for the institution of serf labor, has a negative effect on schooling. This effect diminishes substantially in the second half of the century. Causality of this relationship is confirmed by in...

  10. Transformation thermodynamics: cloaking and concentrating heat flux. (United States)

    Guenneau, Sebastien; Amra, Claude; Veynante, Denis


    We adapt tools of transformation optics, governed by a (elliptic) wave equation, to thermodynamics, governed by the (parabolic) heat equation. We apply this new concept to an invibility cloak in order to thermally protect a region (a dead core) and to a concentrator to focus heat flux in a small region. We finally propose a multilayered cloak consisting of 20 homogeneous concentric layers with a piecewise constant isotropic diffusivity working over a finite time interval (homogenization approach).

  11. Platelet Concentrates: Past, Present and Future



    Platelets play a crucial role in hemostasis and wound healing, platelet growth factors are well known source of healing cytokines. Numerous techniques of autologous platelet concentrates have been developed and applied in oral and maxillofacial surgery. This review describes the evolution of the first and second generation of platelet concentrates (platelet rich plasma and platelet rich fibrin respectively) from their fore runner-fibrin sealants.

  12. Whole blood selenium concentrations in endurance horses. (United States)

    Haggett, Emily; Magdesian, K Gary; Maas, John; Puschner, Birgit; Higgins, Jamie; Fiack, Ciara


    Exercise causes an increase in the production of reactive oxygen species, which can result in oxidant/antioxidant disequilibrium. Deficiency of antioxidants can further alter this balance in favor of pro-oxidation. Selenium (Se) is one of many antioxidant catalysts, as a component of the glutathione peroxidase enzymes. Soils and forages vary widely in Se concentration and a deficient diet can lead to sub-clinical or clinical deficiency in horses. Endurance horses are prone to oxidative stress during long periods of aerobic exercise and their performance could be affected by Se status. This study investigated the blood Se concentration in a group of endurance horses (n=56) residing and competing in California, a state containing several regions that tend to produce Se-deficient forages. The rate of Se deficiency in this group of horses was low, with only one horse being slightly below the reference range. Higher blood Se concentrations were not associated with improved performance in terms of ride time. There was no significant difference in Se concentration between horses that completed the ride and those that were disqualified, although blood Se concentrations were significantly higher in horses that received oral Se supplementation. An increase in blood Se concentration was observed following exercise and this warrants further study.

  13. Normal and pathologic concentrations of uremic toxins. (United States)

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


    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-microglobulin, indoxyl sulfate, homocysteine, uric acid, and parathyroid hormone. We found most solutes (59%) in only one report. Compared with previous results, more recent articles reported higher uremic concentrations of many solutes, including carboxymethyllysine, cystatin C, and parathyroid hormone. However, five solutes had uremic concentrations less than 10% of the originally reported values. Furthermore, the uremic concentrations of four solutes did not exceed their respective normal concentrations, although they had been previously described as uremic retention solutes. In summary, this review extends the classification of uremic retention solutes and their normal and uremic concentrations, and it should aid the design of experiments to study the biologic effects of these solutes in CKD.

  14. Indoor radon concentrations in Adana, Turkey. (United States)

    Degerlier, M; Celebi, N


    The indoor radon concentration in Adana, Turkey was measured in living rooms of 52 houses during winter 2005 and 57 houses during summer 2005. Forty-four houses were selected for both winter and summer researches for estimating seasonal variations. Indoor radon concentrations were measured seasonally over hotter and colder 2 months over the whole year, using CR-39 passive nuclear track radon detectors. The radon concentrations were ranged from 15 to 97 Bq m(-3) on January-February 2005 for 60 d and from 5 to 70 Bq m(-3) on June-July 2005 for 60 d. The average summer concentration measured was 25.8 Bq m(-3) and the average winter concentration was 48.9 Bq m(-3) in 44 houses that observed seasonal variations. The differences between winter and summer periods were ranged from 1 to 77 Bq m(-3). The average value in both winter and summer periods is 37 Bq m(-3) in 44 houses that observed seasonal variations. This value is below the worldwide indoor radon concentration distribution of 46 Bq m(-3). The annual effective dose equivalent from (222)Rn was 0.9 mSv y(-1).

  15. The statistics of Λ CDM halo concentrations (United States)

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


    We use the Millennium Simulation (MS) to study the statistics of Λ cold dark matter (ΛCDM) halo concentrations at z = 0. Our results confirm that the average halo concentration declines monotonically with mass; the concentration-mass relation is well fitted by a power law over three decades in mass, up to the most massive objects that form in a ΛCDM universe (~ 1015h-1Msolar). 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, allows 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 >~ 3 × 1014h-1Msolar) have concentrations exceeding c200 = 7.5, a result that may be useful in interpreting the likelihood of unusually strong massive gravitational lenses, such as Abell 1689, in the ΛCDM cosmogony. A similar fraction of about 1 per cent of galaxy-sized haloes (M200 ~ 1012h-1Msolar) have c200 < 4.5 and this could be relevant to models that attempt to reconcile the ΛCDM cosmology with rotation curves of low surface brightness galaxies by appealing to haloes of unexpectedly low concentration. We find that halo concentrations are independent of spin once haloes manifestly out of equilibrium have been removed from the sample. Compared to their relaxed brethren, the concentrations of out-of-equilibrium haloes tend to be lower and have more scatter, while their spins tend to be higher. A number of previously noted trends within the halo population are induced primarily by these properties of unrelaxed systems. Finally, we compare the result of predicting halo concentrations using the mass assembly history of the main progenitor with predictions based on simple arguments regarding the assembly time of all progenitors

  16. Atmospheric relative concentrations in building wakes

    Energy Technology Data Exchange (ETDEWEB)

    Ramsdell, J.V. Jr.; Simonen, C.A.


    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.

  17. Equilibrium bed—concentration of nonuniform sediment

    Institute of Scientific and Technical Information of China (English)

    孙志林; 孙志锋; DONAHUEJohn


    Knowledge of the equilibrium bed-concentration is vital to mathematical modeling of the river-bed deformation associated with suspended load but previous investigations only daelt with the reference concentra-tion of uniform sediment because of difficulties in observation of the bed-concentration.This work is a first at-tempe to develop a theoretical formula for the equilibrium bed-concentration of any fraction of nonumiform sedi-ment defined at the bed-surface.The formula is based on a stochastic-mechanistic model for the exchange of nonumiform sediment near the bed,and described as a function of incipient motion probability,non-ceasing probability,pick-up probability,and the ratio of the average single-step continuous motion time to static time.Comparison of bed-concentration calculated from the proposed formula with the measured data showed satisfac-tory agreement,indicating the present formula can be used for solving the differential equation governing the notion of suspended load.

  18. 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


    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...

  19. 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


    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.

  20. A Review of Solar Photovoltaic Concentrators

    Directory of Open Access Journals (Sweden)

    Mehrdad Khamooshi


    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.

  1. 'Null method' determination of drug biophase concentration. (United States)

    Tallarida, Ronald J; Lamarre, Neil; Raffa, Robert B


    PK/PD modeling is enhanced by improvements in the accuracy of its metrics. For PK/PD modeling of drugs and biologics that interact with enzymes or receptors, the equilibrium constant of the interaction can provide critical insight. Methodologies such as radioliogand binding and isolated tissue preparations can provide estimates of the equilibrium constants (as the dissociation constant, K value) for drugs and endogenous ligands that interact with specific enzymes and receptors. However, an impediment to further precision for PK/PD modeling is that it remains a problem to convert the concentration of drug in bulk solution (A) into an estimate of receptor occupation, since A is not necessarily the concentration (C) of drug in the biophase that yields fractional binding from the law of mass action, viz., C/(C + K). In most experimental studies A is much larger than K, so the use of administered instead of biophase concentration gives fractional occupancies very close to unity. We here provide a simple way to obtain an estimate of the factor that converts the total drug concentration into the biophase concentration in isolated tissue preparation. Our approach is an extension of the now classic 'null method' introduced and applied by Furchgott to determination of drug-receptor dissociation constants.

  2. Serum prolactin concentrations are elevated after syncope. (United States)

    Oribe, E; Amini, R; Nissenbaum, E; Boal, B


    The distinction between syncope and epileptic seizures is a common clinical diagnostic problem. Elevated serum prolactin (PRL) concentrations are used to help differentiate epileptic from nonepileptic attacks such as pseudoseizures. Reports of PRL concentrations following syncope have been variable. To determine whether PRL rises after syncope, we measured serum PRL concentrations during a 45-minute passive 60-degree head-up tilt in 21 patients with a history of near-fainting or syncope. Head-up tilt triggered hypotension (mean arterial pressure 51 mm Hg, 95% CI = 45-57) with syncope in 11 patients. PRL concentrations were elevated ( > 19 ng/mL) and reached a maximum within the first 30 minutes after tilt-induced syncope in nine patients (PRL supine: 11 ng/mL, 95% CI = 7-15, vs. PRL after syncope: 52 ng/mL, 95% CI = 36-67; a greater than fourfold rise), while they remained unchanged in 10 patients who had a normal response to head-up tilt (PRL supine: 6 ng/mL, 95% CI = 5-8, vs. maximum PRL while upright: 8 ng/mL, 95% CI = 6-10). The findings indicate that elevated PRL concentrations are present after hypotensive syncope and are of little use in differentiating such syncope from epileptic seizures.

  3. Hip implants - Paper VI - Ion concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Sargeant, A. [Department of Biological Sciences, Ohio Northern University, Ada, OH 45810 (United States); Goswami, T. [Department of Mechanical Engineering, Ohio Northern University, Ada, OH 45810 (United States)]. E-mail:


    Total hip-joint arthroplasty is performed in increasing numbers where it translates to about 0.16-0.2% of population per year in industrial countries. In most cases, an implant is a metallic component articulating with a metal, ceramic or poly-ethylene liner as seen in the case of hip, knee and spine. The metal implants release ions in vivo. Therefore, there is a need to study metallic implants and ions released as a result. Toxic concentrations of ions can lead to many adverse physiological effects, including cytotoxicity, genotoxicity, carcinogenicity, and metal sensitivity. There is a need to map ion concentrations establishing boundaries between normal and toxic levels; which however, does not exist. Reference levels of ion concentrations in body fluids and tissues determined by many studies are compiled, reviewed, and presented in this paper. The concentrations of ions released from different alloys, including cobalt, chromium, nickel, molybdenum titanium, aluminum, and vanadium, are presented in this paper. This paper reviews the literature pertaining to clinical data on metal ion concentrations in patients with metal joint prostheses, and laboratory data on the physiological effects of the metals.

  4. 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.

  5. Concentration and purification of plutonium or thorium (United States)

    Hayden, John A.; Plock, Carl E.


    In this invention a first solution obtained from such as a plutonium/thorium purification process or the like, containing plutonium (Pu) and/or thorium (Th) in such as a low nitric acid (HNO.sub.3) concentration may have the Pu and/or Th separated and concentrated by passing an electrical current from a first solution having disposed therein an anode to a second solution having disposed therein a cathode and separated from the first solution by a cation permeable membrane, the Pu or Th cation permeating the cation membrane and forming an anionic complex within the second solution, and electrical current passage affecting the complex formed to permeate an anion membrane separating the second solution from an adjoining third solution containing disposed therein an anode, thereby effecting separation and concentration of the Pu and/or Th in the third solution.

  6. A Cyclist's Guide to Ionic Concentration (United States)

    Last, Arthur M.


    A simple analogy to help students understand ionic concentration is presented. A common problem among beginning chemistry students is the failure to recognize that in a solution containing 0.1 mol L-1 sodium chloride, the concentration of chloride ion is 0.1 mol L-1, not 0.05 mol L-1. Similarly, many students do not understand that in a solution containing 0.1 mol L-1 magnesium chloride, the concentration of chloride ion is 0.2 mol L-1. To help students overcome such problems, an analogy has been developed in which a salt such as sodium chloride is compared to a unicycle, consisting of a frame and a wheel; magnesium chloride is compared to a bicycle, consisting of a frame and two wheels; and so on. Complete (i.e., 100%) dissociation is assumed throughout the discussion.

  7. Large scale water lens for solar concentration. (United States)

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


    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.

  8. A cellular glass substrate solar concentrator (United States)

    Bedard, R.; Bell, D.


    The design of a second generation point focusing solar concentration is discussed. The design is based on reflective gores fabricated of thin glass mirror bonded continuously to a contoured substrate of cellular glass. The concentrator aperture and structural stiffness was optimized for minimum concentrator cost given the performance requirement of delivering 56 kWth to a 22 cm diameter receiver aperture with a direct normal insolation of 845 watts sq m and an operating wind of 50 kmph. The reflective panel, support structure, drives, foundation and instrumentation and control subsystem designs, optimized for minimum cost, are summarized. The use of cellular glass as a reflective panel substrate material is shown to offer significant weight and cost advantages compared to existing technology materials.

  9. Urinary bisphenol A concentrations in pregnant women. (United States)

    Callan, Anna Carita; Hinwood, Andrea Lee; Heffernan, Amy; Eaglesham, Geoff; Mueller, Jochen; Odland, Jon Øyvind


    Bisphenol A is a chemical that is present in a number of products and types of food packaging. Prenatal exposure to bisphenol A may cause behavioural changes in young children. The aim of this study was to investigate exposure to bisphenol A in pregnant Australian women as a surrogate of neonatal exposure. First morning void urine samples were collected from 26 pregnant women at around week 38 of gestation. Bisphenol A was detectable in 85% of the samples analysed. The median concentration in this group of women was 2.41μg/L with a range of bisphenol A concentrations, as did women with a pre-pregnancy BMI of bisphenol A exposure in Australia and reveals that pregnant women have measured biological concentrations of urinary bisphenol A similar to those reported for pregnant women in other developed countries. Given the potential impacts of prenatal bisphenol A exposure, further research in this area is warranted.

  10. Seasonal Variation in Human Salivary Cortisol Concentration

    DEFF Research Database (Denmark)

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


    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...... 32 to 61 yrs of age engaged in active work. On one workday for 12 consecutive months, participants collected saliva at four time points for determination of cortisol: at awakening, +30 min, +8 h, and at 21:00 h. Data were analyzed by a repeated measures design with month (12 levels) and time...

  11. Scalar Casimir effect between two concentric spheres

    CERN Document Server

    Ozcan, Mustafa


    The Casimir effect giving rise to an attractive force between the closely spaced two concentric spheres that confine the massless scalar field is calculated by using a direct mode summation with contour integration in the complex plane of eigenfrequencies. We devoleped a new approach appropriate for the calculation of the Casimir energy for spherical boundary conditions. The Casimir energy for a massless scalar field between the closely spaced two concentric spheres coincides with the Casimir energy of the parallel plates for a massless scalar field in the limit when the dimensionless parameter {\\eta}, ({\\eta}=((a-b)/(\\surd(ab))) where a (b) is inner (outer) radius of sphere), goes to zero. The efficiency of new approach is demonstrated by calculation of the Casimir energy for a massless scalar field between the closely spaced two concentric half spheres. PACS number(s): 03.70.+k, 12.20.DS, 11.10.Gh

  12. Removal Of Volatile Impurities From Copper Concentrates

    Energy Technology Data Exchange (ETDEWEB)

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


    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)

  13. Regional Specialisation and Economic Concentration in Romania

    Directory of Open Access Journals (Sweden)

    Neagu Olimpia


    Full Text Available The purpose of the paper is to give an overview of the changes in the structure of industries in Romania, specifically on the questions (1 whether the industrial structures become more similar or more different in the Romanian regions and (2 whether the Romanian industries become more concentrated or more dispersed. EUROSTAT regional data on Gross Value Added and employed population for the period of 2000-2013 are used in order to calculate several statistical indices of specialization and concentration (Krugman, Entropy, Hirschman-Herfindahl, Lilien Index and Gini coefficient. By comparing the values of these different measurements, the main finding is that Romanian regions become less specialized, while industries become slightly more concentrated. The speed of structural changes in all Romanian regions registered a noticeable slowdown of the speed of sectoral changes after the economic crisis. Our conclusions provide useful information for the economic policy makers in investment funds allocation or employment measures designing.

  14. Organic Wheat Farming Improves Grain Zinc Concentration. (United States)

    Helfenstein, Julian; Müller, Isabel; Grüter, Roman; Bhullar, Gurbir; Mandloi, Lokendra; Papritz, Andreas; Siegrist, Michael; Schulin, Rainer; Frossard, Emmanuel


    Zinc (Zn) nutrition is of key relevance in India, as a large fraction of the population suffers from Zn malnutrition and many soils contain little plant available Zn. In this study we compared organic and conventional wheat cropping systems with respect to DTPA (diethylene triamine pentaacetic acid)-extractable Zn as a proxy for plant available Zn, yield, and grain Zn concentration. We analyzed soil and wheat grain samples from 30 organic and 30 conventional farms in Madhya Pradesh (central India), and conducted farmer interviews to elucidate sociological and management variables. Total and DTPA-extractable soil Zn concentrations and grain yield (3400 kg ha-1) did not differ between the two farming systems, but with 32 and 28 mg kg-1 respectively, grain Zn concentrations were higher on organic than conventional farms (t = -2.2, p = 0.03). Furthermore, multiple linear regression analyses revealed that (a) total soil zinc and sulfur concentrations were the best predictors of DTPA-extractable soil Zn, (b) Olsen phosphate taken as a proxy for available soil phosphorus, exchangeable soil potassium, harvest date, training of farmers in nutrient management, and soil silt content were the best predictors of yield, and (c) yield, Olsen phosphate, grain nitrogen, farmyard manure availability, and the type of cropping system were the best predictors of grain Zn concentration. Results suggested that organic wheat contained more Zn despite same yield level due to higher nutrient efficiency. Higher nutrient efficiency was also seen in organic wheat for P, N and S. The study thus suggests that appropriate farm management can lead to competitive yield and improved Zn concentration in wheat grains on organic farms.


    Directory of Open Access Journals (Sweden)

    Krzysztof Skotak


    Full Text Available Ozone in the lower part of the atmosphere (troposphere, strong photochemical oxidant, is not directly emitted to the atmosphere but formed through a series of complex reactions. Ozone concentrations depends on ozone precursors air contamination (mainly nitrogen dioxide and non-methane volatile organic compounds and meteorological conditions (temperature and solar radiation. The main sectors emitted ozone precursors are road transport, power and heat generation plants, household (heating, industry, and petrol storage and distribution. Ozone and some of its precursors are also transported long distances in the atmosphere and are therefore considered a transboundary problem. As a result, the ozone concentrations are often low in busy urban areas and higher in suburban and rural areas. Nowadays, instead of particulate matter, ozone is one of the most widespread global air pollution problems. In and around urban areas, relatively large gradients of ozone can be observed. Because of its high reactivity in elevated concentrations ozone causes serious health problems and damage to ecosystems, agricultural crops and materials. Main ill-health endpoints as a results of ozone concentrations can be characterised as an effect of pulmonary and cardiovascular system, time morbidity and mortality series, development of atherosclerosis and asthma and finally reduction in life expectancy. The associations with increased daily mortality due to ozone concentrations are confirmed by many researches and epidemiological studies. Estimation of the level selected ill-health endpoints (mortality in total and due to cardiovascular and respiratory causes as a result of the short-term ozone exposure in Poland was the main aim of the project. Final results have been done based on estimation method elaborated by WHO, ozone measurements from National Air Quality Monitoring System and statistical information such as mortality rate and populations. All analysis have been done in


    Directory of Open Access Journals (Sweden)

    Luiz Moreira Coelho Junior


    Full Text Available 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.

  17. Beryllium concentration in pharyngeal tonsils in children. (United States)

    Nogaj, Ewa; Kwapulinski, Jerzy; Misiołek, Maciej; Golusiński, Wojciech; Kowol, Jolanta; Wiechuła, Danuta


    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.

  18. Beryllium concentration in pharyngeal tonsils in children

    Directory of Open Access Journals (Sweden)

    Ewa Nogaj


    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.

  19. Time-series analysis for ambient concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Manteiga, W.; Prada-Sanchez, J.M.; Cao, R.; Garcia-Jurado, I.; Febrero-Bande, M.; Lucas-Dominguez, T. (Santiago de Compostela University, Santiago de Compostela (Spain). Dept. of Statistics and Operations Research)


    In this paper a dynamic system is presented which has been implemented to predict, every 5 min, the ambient concentrations of SO[sub 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[sub 2]. For forecasting a mixed model is used which has a parametric component and a nonparametric one. Confidence intervals are also constructed for future observations using bootstrap and classical techniques. 4 refs., 5 figs., 3 tabs.

  20. A time-varying magnetic flux concentrator (United States)

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


    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.

  1. Fundamentals of concentric lens systems synthesis (United States)

    Ezhova, Kseniia; Zverev, Victor; Tochilina, Tatiana; Tymoshchuk, Irina


    Introduction of coefficients defining the relationship of the radii of curvature of the surfaces of concentric optical systems, allowed the transformation of the obtained analytical relations in a system of two equations with two unknowns. It is shown that the existence of the solution of the system of equations determined by the optical constants of the selected lens material. The results of the analysis of the conditions of the chromatic aberration correction position and the sequence of obtaining of the system equations define the theoretical basis of the engineering method of parametric synthesis of concentric lens systems. Application of the developed method is illustrated by examples of calculation particular systems design build.

  2. Plasma lipid concentrations for some Brazilian lizards. (United States)

    Gillett, M P; Lima, V L; Costa, J C; Sibrian, A M


    1. Plasma concentrations of cholesterol, cholesteryl esters, phospholipids and triglycerides were determined for ten species of Brazilian lizards, Iguana iguana, Tropidurus torquatos and T. semitaeniatus (Iguanidae), Tupinambis teguixin, Ameiva ameiva and Cnemidophorus ocellifer (Teiidae), Mabuya maculata (Scincidae), Hemidactylus mabouia (Gekkonidae), Amphisbaenia vermicularis and Leposternon polystegum (Amphisbaenidae). 2. Considerable inter- and intra-species variations in plasma lipid concentrations were observed. 3. The percentage of total cholesterol esterified and the individual phospholipid composition of plasma were relatively constant for each species. 4. Over 60% of the cholesteryl esters present in plasma from three species each of iguanid and teiid lizards were polyenoic.

  3. Maximum phytoplankton concentrations in the sea

    DEFF Research Database (Denmark)

    Jackson, G.A.; Kiørboe, Thomas


    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 collected...... 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 predictions...

  4. Advertising and Concentration in the Brewing Industry

    DEFF Research Database (Denmark)

    Madsen, Erik Strøjer; Wu, Yanqing


    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 wo......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...

  5. Planar Micro-Optic Solar Concentration (United States)

    Karp, Jason Harris

    Solar radiation can be converted directly into electricity with materials exhibiting a photovoltaic response. Most photovoltaic arrays use crystalline silicon cells assembled in large modules which convert 80% optical efficiency at 300x geometric concentration. In addition, I develop a self-aligned fabrication process to assemble several small-scale prototypes using commercially-available components. These systems were experimentally measured at 52.3% optical efficiency. Lastly, I show how the waveguide geometry can be exploited to increase performance and add functionality within concentrator photovoltaic systems.

  6. 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


    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.

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

    NARCIS (Netherlands)

    Cunningham, S.; Werker, C.


    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

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

    CERN Document Server

    Maragliano, Carlo; Stefancich, Marco


    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...

  9. Sunflower meal concentrations in Massai grass silage

    Directory of Open Access Journals (Sweden)

    Máikal S. Borja


    Full Text Available Objetive. 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 high quality silage. The addition of sunflower meal showed a linear increase in crude protein, reaching 18% DM with the highest concentration of sunflower meal. The highest feed value index was obtained with the addition of 24% sunflower meal in the silage. The estimated total digestible nutrient of silage increased linearly with sunflower meal concentration. The silage pH values had a quadratic effect, reaching the lowest value (4.1 with 15% sunflower meal addition. Conclusions. Based on the chemical composition and forage quality, a concentration of 14% sunflower meal should be used for high-quality silage with good nutritional value.

  10. Oceanic Methane Concentrations in Three Mexican Regions (United States)

    The atmospheric concentration of methane has increased significantly over the last several decades. Methane is an important greenhouse gas, and it is important to better quantify methane sources and sinks. Dissolved methane in the ocean is produced by biological and hydrothermal ...

  11. Heat stability of concentrated skim milk.

    NARCIS (Netherlands)

    Nieuwenhuijse, J.A.


    Heat-induced coagulation of concentrated skim milk was studied. Heat-induced changes in partition between serum and colloidal particles of calcium and phosphate and of the various proteins were investigated as a function of heating time and conditions like pH, addition of phosphate and preheating. A

  12. Critical Concentration Ratio for Solar Thermoelectric Generators (United States)

    ur Rehman, Naveed; Siddiqui, Mubashir Ali


    A correlation for determining the critical concentration ratio (CCR) of solar concentrated thermoelectric generators (SCTEGs) has been established, and the significance of the contributing parameters is discussed in detail. For any SCTEG, higher concentration ratio leads to higher temperatures at the hot side of modules. However, the maximum value of this temperature for safe operation is limited by the material properties of the modules and should be considered as an important design constraint. Taking into account this limitation, the CCR can be defined as the maximum concentration ratio usable for a particular SCTEG. The established correlation is based on factors associated with the material and geometric properties of modules, thermal characteristics of the receiver, installation site attributes, and thermal and electrical operating conditions. To reduce the number of terms in the correlation, these factors are combined to form dimensionless groups by applying the Buckingham Pi theorem. A correlation model containing these groups is proposed and fit to a dataset obtained by simulating a thermodynamic (physical) model over sampled values acquired by applying the Latin hypercube sampling (LHS) technique over a realistic distribution of factors. The coefficient of determination and relative error are found to be 97% and ±20%, respectively. The correlation is validated by comparing the predicted results with literature values. In addition, the significance and effects of the Pi groups on the CCR are evaluated and thoroughly discussed. This study will lead to a wide range of opportunities regarding design and optimization of SCTEGs.

  13. Concentration polarization in nanochannel DNA electrophoresis

    NARCIS (Netherlands)

    Dubsky, Pavel; Das, Siddhartha; Berg, van den Albert; Eijkel, Jan C.T.


    We demonstrate that the large field electrophoresis of a single DNA molecule in nanofluidic systems is accompanied by concentration polarization. We illustrate this phenomena by utilizing our electrophoretic simulation tool SIMUL. First we in-vestigate a simple system with univalent strong electroly

  14. Monazite in concentrations from Idaho placer operations (United States)


    During the summer of 1947 the Atomic Energy Commission informally requested the Geological Survey collect sampled of concentrates from Idaho placer operations that might be useful for experimental study of monazite recovery. Some fourteen active gold-dredging operations were examined and sampled by Fred M. Chase during August and September 1947.

  15. Concentrating Solar Power Commercial Application Study

    Energy Technology Data Exchange (ETDEWEB)



    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.”


    Institute of Scientific and Technical Information of China (English)

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


    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.

  17. Formoterol concentrations in blood and urine

    DEFF Research Database (Denmark)

    Eibye, Kasper; Elers, Jimmi; Pedersen, Lars


    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....

  18. Neighborhood Variation in Gang Member Concentrations (United States)

    Katz, Charles M.; Schnebly, Stephen M.


    This study examines the relationship between neighborhood structure, violent crime, and concentrations of gang members at the neighborhood level. We rely on official police gang list data, police crime data, and two waves of decennial census data characterizing the socioeconomic and demographic conditions of 93 neighborhoods in Mesa, Arizona.…

  19. 40 CFR 264.94 - Concentration limits. (United States)


    ... present or potential hazard to human health or the environment as long as the alternate concentration... consider the following factors: (1) Potential adverse effects on ground-water quality, considering: (i) The... migration; (ii) The hydrogeological characteristics of the facility and surrounding land; (iii) The...

  20. Doxepin concentrations in plasma and cerebrospinal fluid. (United States)

    Schomburg, Robert; Remane, Daniela; Fassbender, Klaus; Maurer, Hans H; Spiegel, Jörg


    Doxepin--like other antidepressant drugs (ADs)--shows a variable antidepressant effect in clinical practice. The cause for this variability is as yet unclear; however, pharmacokinetic factors such as the variable permeability of doxepin into the cerebrospinal fluid (CSF), may contribute to the difference in therapeutic efficacy. We measured and correlated the concentration of doxepin and its active metabolite nordoxepin in both the plasma and CSF. Plasma and CSF samples were taken simultaneously from 21 patients who were treated with doxepin due to different clinical indications. The plasma concentration of both doxepin and nordoxepin correlated significantly with the oral dosage of doxepin (doxepin: r = +0.66, p < 0.001; nordoxepin: r = +0.78, p < 0.0001; Spearman's correlation). Furthermore, we found significant correlations between the plasma and CSF concentrations of both doxepin (r = +0.71; p < 0.001; Pearson's correlation) and nordoxepin (r = +0.74; p < 0.001). These highly significant correlations between the plasma and CSF concentrations indicate a constant CSF permeability of doxepin and its active metabolite nordoxepin.

  1. Risk in A Concentrated Export Market

    Institute of Scientific and Technical Information of China (English)


    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.


    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...

  3. Concentration of lemon pectin extract by ultrafiltration

    Directory of Open Access Journals (Sweden)

    Damián Stechina


    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.


    This paper presents an analysis of trends in atmospheric concentrations of sulfur dioxide (SO,) and particulate sulfate (SO42-) at rural monitoring sites in the Clean Air Act Status and Trends Monitoring Network (CASTNet) from 1990 to 1999. A two-stage approach is used to estimat...

  5. 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


    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.

  6. Self absorption in luminescent solar concentrators

    NARCIS (Netherlands)

    Krumer, Z.


    Luminescent solar concentrators are photovoltaic devices made of thin transparent material, in which luminescent particles are dispersed. The incident light enters the device through its large facets and is subsequently absorbed by the luminescent particles, which re-emit it whilst changing its dire


    Directory of Open Access Journals (Sweden)

    Sanja Sever Mališ


    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.

  8. Lightweight solar concentrator structures, phase 2 (United States)

    Williams, Brian E.; Kaplan, Richard B.


    This report summarizes the results of the program conducted by Ultramet under SBIR Phase 2 Contract NAS3-25418. The objective of this program was to develop lightweight materials and processes for advanced high accuracy Space Solar Concentrators using rigidized foam for the substrate structure with an integral optical surface.

  9. Electrodialysis for the concentration of ethanolamine salts

    NARCIS (Netherlands)

    Groot, de Matheus T.; Bos, Ardina A.C.M.; Peris Lazaro, Alicia; Rooij, de Ralph M.; Bargeman, Gerrald


    Monoethanolamine (MEA) is currently produced from oil-based chemicals in an energy intensive process. Fermentative MEA production from renewable sources is considered to be a more sustainable process option. In such a process MEA is likely to be produced in a relatively low concentration in protonat

  10. Magnetic flux concentrations from turbulent stratified convection

    CERN Document Server

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


    (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 ...


    Directory of Open Access Journals (Sweden)

    N. G. Kul’neva


    Full Text Available Summary. Producing high quality intermediate products in the boiling-crystallization station is an actual problem of sugar production. In the production of white sugar brown sugar syrup is not further purified that decreases the quality of the end product. Studies have been conducted using cellulose as an adsorbent for the purification of concentrated sugar solutions, having affinity to dyes and other impurities. Research have been carried out with the intermediate products of the Lebedyan sugar plant. Test results have shown cellulose ability to adsorb the dyes in sugar production. The influence of the adsorbent concentration and the mass fraction of solids in the syrup on the decolorization effect has been studied; rational process parameters have been obtained. It has been found that proceeding an additional adsorption purification of brown sugars syrup allows to reduce the solution color, increase the amount and quality of the end product. Adsorbing means, received from production wastes on the basis of organic resources, have many advantages: economical, environmentally friendly for disposal, safe to use, reliable and efficient in use. Conducted research on using cellulose as adsorbent for treatment of concentrated sugar solutions, having an affinity for colouring matter and other impurities. The experiments were carried out on the intermediates Lebedyanskiy sugar factory. The test results showed the ability of cellulose to adsorb coloring matter of sugar production. To evaluate the effect of bleaching depending on the mass fraction of dry substances prepared yellow juice filtration of sugar concentration of 55, 60, 65 % with subsequent adsorption purification of cellulose. The results of the experiment built adsorption isotherm of dyestuffs. The influence of the concentration of the adsorbent and a mass fraction of solids of juice filtration on the efficiency of decolorization obtained by rational parameters of the process. It is

  12. Concentrating Solar Power. Report April 2009

    Energy Technology Data Exchange (ETDEWEB)

    Pihl, Erik (Chalmers Univ. of Technology, Enery and Environment, Goeteborg (Sweden))


    Concentrating solar power (CSP) technologies offer ways to utilise solar radiation by concentrating the light. In a concentrated form, the light can be utilised more cost efficiently. It is focused with mirrors or lenses and used either as a heat source in thermal power cycles (thermal CSP) or as a light source for high efficiency photovoltaic cells (concentrating photovoltaics, CPV). All concentrating systems use tracking to follow the movement of the sun, in two or three dimensions, and require direct sunlight (no diffusing clouds). CSP plants are often more complex, component wise than those based on flat PV. The extra cost of complexity is generally more than offset by the larger scales, the less need for expensive materials such as purified silicon and a better fit with the current energy infrastructure. Some thermal CSP plants offer great possibilities to deal with the intermittency of solar energy, as the heat generated can be stored in the form of a heated liquid in large tanks for many hours with little additional cost, and drive the thermal power generation also during cloudy periods or at night. CSP is growing rapidly and can be an important portion of future low-carbon energy systems. A prerequisite is that expected cost reductions are, at least largely, realised. In regions with good solar conditions (Mediterranean countries, US Southwest, Middle East, Australia etc), CSP systems already in the short-term future can satisfy significant shares of the power demand, to decrease CO{sub 2} emissions. Less solar-intensive regions (Northern Europe, much of North America etc) can be supplied with CSP power from solar-rich regions by using long distance power grids, for instance the high voltage DC cables being deployed and developed today

  13. Concentration uniformity of extemporaneously prepared ranitidine suspension. (United States)

    Karnes, H T; Harris, S R; Garnett, W R; March, C


    The concentration uniformity of an extemporaneously prepared ranitidine suspension was studied. To prepare the ranitidine suspension, 36 150-mg tablets were pulverized and suspended in 180 mL of distilled water. This mixture was diluted with simple syrup to a total volume of 360 mL, resulting in a final ranitidine concentration of 150 mg/10 mL. Samples from each of three bottles that had been filled with 60 mL of the suspension were assayed for ranitidine content by high-performance liquid chromatography. The sedimentation of suspended ranitidine tablet particles was studied by visual observation of the setting process in 10-mL samples from the same batch. The overall mean concentrations (in milligrams per milliliter) of ranitidine were 14.53, 15.25, 13.92, 12.67, and 12.72 at 0, 3, 7, 14, and 21 days, respectively. Compared with baseline, the difference in the ranitidine concentration was not significant over days 0-7. The ranitidine concentration was significantly reduced during the following time intervals: days 0-14, days 0-21, and days 7-21. In the settling experiments, the mean time (+/- S.D.) for sediment to first appear on the test tube bottom was 14.67 +/- 5.35 seconds. Approximately 40-50% (mean level = 3.2 mm) of the total sedimentation level (mean level = 7.3 mm) was observed one minute after shaking. The uniformity of ranitidine suspensions compounded according to procedures described in this report possibly could be improved with sonication. The ranitidine suspension should be well shaken, the dosage should be measured immediately after shaking, and the suspension should be used within seven days of compounding.

  14. Concentrated insulins: the new basal insulins

    Directory of Open Access Journals (Sweden)

    Lamos EM


    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

  15. 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:;;


    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

  16. Concentration Places, Concentration Evolutions, and Online Information Retrieval Techniques for Calculating Them. (United States)

    Egghe, L.


    Presents a mathematical theory that can be used to define concentration places of objects within unordered classes. The application to research on the evolution of journals and subject areas is illustrated, and an online method of calculating concentration evolution is described. (1 references) (CLB)

  17. Maximum Permissible Concentrations and Negligible Concentrations for Rare Earth Elements (REEs)

    NARCIS (Netherlands)

    Sneller FEC; Kalf DF; Weltje L; Wezel AP van; CSR


    In this report maximum permissible concentrations (MPCs) and negligible concentrations (NCs) are derived for Rare Earth Elements (REEs), which are also known as lanthanides. The REEs selected for derivation of environmental risk limits in this report are Yttrium (Y), Lanthanum (La), Cerium (Ce), Pra

  18. 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.


    -swath synthetic aperture radar (SAR) scenes. The analysis is confined to the high-concentration Arctic sea ice, where the ice cover is near 100%. During winter the results indicate that the variability of the SSM/I concentration estimates is larger than the true variability of ice concentration. Results from...... a 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......[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...

  19. Stationary SMS lenses for concentrating photovoltaics (United States)

    Kotsidas, Panagiotis; Chatzi, Eleni; Modi, Vijay


    This paper presents a novel approach regarding the design of stationary, non imaging, refractive lenses with high acceptance angles. A lens lies on a stationary aperture and as the sun moves throughout the day, the concentrated focal spot is tracked by a moving solar cell. The purpose of this work is to replace the 2-axis tracking of the sun with internal motion of the miniaturized solar cell inside the module. We show families of linear lenses with wide acceptance angles 60. and 30. achieving moderate concentrations of 10 - 30 suns. The lens is designed with a variation of the simultaneous multiple surface (SMS) technique which is combined with a genetic algorithm to optimize the free variables of the problem.

  20. Spot Spraying Reduces Herbicide Concentrations in Runoff. (United States)

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


    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.

  1. A Quantum Algorithm Detecting Concentrated Maps. (United States)

    Beichl, Isabel; Bullock, Stephen S; Song, Daegene


    We consider an arbitrary mapping f: {0, …, N - 1} → {0, …, N - 1} for N = 2 (n) , n some number of quantum bits. Using N calls to a classical oracle evaluating f(x) and an N-bit memory, it is possible to determine whether f(x) is one-to-one. For some radian angle 0 ≤ θ ≤ π/2, we say f(x) is θ - concentrated if and only if [Formula: see text] for some given ψ 0 and any 0 ≤ x ≤ N - 1. We present a quantum algorithm that distinguishes a θ-concentrated f(x) from a one-to-one f(x) in O(1) calls to a quantum oracle function Uf with high probability. For 0 quantum algorithm outperforms random (classical) evaluation of the function testing for dispersed values (on average). Maximal outperformance occurs at [Formula: see text] rad.

  2. Generalized principles of unchanging total concentration. (United States)

    Kottke, Peter A; Fedorov, Andrei G


    We consider the transport of multiple reacting species under the continuum assumption in situations such as those that frequently arise in electroanalytical chemistry. Under certain limitations, it has been shown that the total species concentration (as defined by Oldham and Feldberg) of such a system is uniform and constant. In this work, we extend the limits of the previous analysis to enable greater applicability. This is accomplished by using either of two new dependent variables, which are generalizations of the concept of total concentration. Then, conditions are determined under which the dependent variable will be uniform and constant in time. From a practical viewpoint, the described formalism allows one to simplify the multispecies transport problem formulation by eliminating one equation from the system of governing equations.

  3. Measurement of solid concentration using Terahertz technique

    Institute of Scientific and Technical Information of China (English)

    Liu Yi'an; Huang Zhiyao; Ji Haifeng; Wang Baoliang; Li Haiqing


    Terahertz(THz)technique is a new measurement technique that has emerged in recent years. For the measurement of solid concentration, a radiation attenuation method and a phase delay method were developed, which are based on the Beer-Lambert law. Experimental work was carried out on a terahertz time-domain spectroscopy system (THz-TDS). Results obtained verify that the terahertz technique may provide a possible new solution to the problem of solid concentration measurement and the two proposed measurement methods are effective. Experiment results also indicate that the phase delay method is more accurate than the radiation attenuation method and the size of the particles affects the measurement results of both methods.

  4. Measurement of nutrient concentration in soybean seeds

    Directory of Open Access Journals (Sweden)

    Wellington de Azambuja Magalhães


    Full Text Available This work was to evaluate the concentration of mineral nutrients in soybean seeds of different sizes. The experiment was conducted in Lucas do Rio Verde, MT, at the Escola Técnica Estadual de Ensino Profissional e Tecnológica. The seeds used were the following varieties and size: GMT 132 with 5, 6 and 7 mm; Pioneer P98Y11 6, 7 and 8 mm; Nidera NS 8270 with 7 to 8 mm. The elements N, P and K have higher accumulation in seeds, regardless of the diameter thereof. The nitrogen tend to exhibit greater accumulation with increasing diameter of the seeds. The nutrients P, Ca, Mg and Mn concentration decreases with increasing diameter of the seeds.

  5. Methods and systems for concentrated solar power (United States)

    Ma, Zhiwen


    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.

  6. Big Crunch-based omnidirectional light concentrators

    CERN Document Server

    Smolyaninov, Igor I


    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.

  7. Cellulase Inhibition by High Concentrations of Monosaccharides

    DEFF Research Database (Denmark)

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


    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...... monosaccharides such as mannose and galactose (stereoisomers of glucose) decrease glucose yields as well. NMR relaxometry measurements showed direct correlations between the initial T 2 of the liquid phase in which hydrolysis takes place and the total glucose production during cellulose hydrolysis, indicating...... 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...

  8. 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: [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)


    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.

  9. Concentration Distribution in a Mixing Ventilated Room

    DEFF Research Database (Denmark)

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


    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...... 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....

  10. Magnetoresistive system with concentric ferromagnetic asymmetric nanorings

    Energy Technology Data Exchange (ETDEWEB)

    Avila, J. I., E-mail:; Tumelero, M. A.; Pasa, A. A.; Viegas, A. D. C. [Laboratório de Filmes Finos e Superfícies (LFFS), Departamento de Física, Universidade Federal de Santa Catarina, CP 476 Florianópolis (Brazil)


    A structure consisting of two concentric asymmetric nanorings, each displaying vortex remanent states, is studied with micromagnetic calculations. By orienting in suitable directions, both the asymmetry of the rings and a uniform magnetic field, the vortices chiralities can be switched from parallel to antiparallel, obtaining in this way the analogue of the ferromagnetic and antiferromagnetic configurations found in bar magnets pairs. Conditions on the thickness of single rings to obtain vortex states, as well as formulas for their remanent magnetization are given. The concentric ring structure enables the creation of magnetoresistive systems comprising the qualities of magnetic nanorings, such as low stray fields and high stability. A possible application is as contacts in spin injection in semiconductors, and estimations obtained here of magnetoresistance change for a cylindrical spin injection based device show significant variations comparable to linear geometries.

  11. Turbidimetry for measurement of radon concentration

    Energy Technology Data Exchange (ETDEWEB)

    Wang Huanqiang [HuBei Provincial Academy of Medical Sciences, WuHan (China). Inst. of Radioactive Protection


    This paper describes a turbidimetric technique counting the tracks registered on CR-39 foils exposed to radon. Instead of eyeview through microscope, by using the differential spectrophotometer, strong correlation between the radon cumulative concentration and track turbidence was observed(r=0.999). Under the etching condition of 7.07 mol{center_dot}L{sup -1} KOH water solution at 80{sup o}C for 16 hr, linear regression showed that the ratio of track turbidence and cumulative concentration of radon exposure was 1.99 x 10{sup -1} turbidence (KBq m{sup -1}h){sup -1} and the determination limit was 36 KBq m{sup -3}h. The details of the experiments are represented in this paper. (Author).

  12. Overflow Concentration and Sedimentation in Hoppers

    DEFF Research Database (Denmark)

    Hjelmager Jensen, Jacob; Saremi, Sina


    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...... stages can be captured using a sediment budget approach, i.e., by using continuity equations for water and sediment phases. In this study, the compositional transformation and the bed height inside the hopper are obtained by solving these equations, considering monodisperse, bidisperse, and polydisperse...... 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...

  13. Estimation of surface area concentration of workplace incidental nanoparticles based on number and mass concentrations (United States)

    Park, J. Y.; Ramachandran, G.; Raynor, P. C.; Kim, S. W.


    Surface area was estimated by three different methods using number and/or mass concentrations obtained from either two or three instruments that are commonly used in the field. The estimated surface area concentrations were compared with reference surface area concentrations (SAREF) calculated from the particle size distributions obtained from a scanning mobility particle sizer and an optical particle counter (OPC). The first estimation method (SAPSD) used particle size distribution measured by a condensation particle counter (CPC) and an OPC. The second method (SAINV1) used an inversion routine based on PM1.0, PM2.5, and number concentrations to reconstruct assumed lognormal size distributions by minimizing the difference between measurements and calculated values. The third method (SAINV2) utilized a simpler inversion method that used PM1.0 and number concentrations to construct a lognormal size distribution with an assumed value of geometric standard deviation. All estimated surface area concentrations were calculated from the reconstructed size distributions. These methods were evaluated using particle measurements obtained in a restaurant, an aluminum die-casting factory, and a diesel engine laboratory. SAPSD was 0.7-1.8 times higher and SAINV1 and SAINV2 were 2.2-8 times higher than SAREF in the restaurant and diesel engine laboratory. In the die casting facility, all estimated surface area concentrations were lower than SAREF. However, the estimated surface area concentration using all three methods had qualitatively similar exposure trends and rankings to those using SAREF within a workplace. This study suggests that surface area concentration estimation based on particle size distribution (SAPSD) is a more accurate and convenient method to estimate surface area concentrations than estimation methods using inversion routines and may be feasible to use for classifying exposure groups and identifying exposure trends.

  14. Degadation of semiconducting polymers by concentrated sunlight

    DEFF Research Database (Denmark)

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


    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....

  15. Fermentative hydrogen production at high sulfate concentration

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chin-Chao [Environmental Resources Laboratory, Department of Landscape Architecture, Chungchou Institute of Technology, Changhwa 51022 (China); Chen, Hong-Pin; Wu, Jou-Hsien; Lin, Chiu-Yue [BioHydrogen Laboratory, Department of Water Resource Engineering, Feng Chia University, P.O. Box 25-123, Taichung 40724 (China)


    The hydraulic retention time (HRT) effects on fermentative hydrogen production from sucrose at high sulfate concentration of 3 g-SO{sub 4}{sup 2-}/l were studied using enriched mixed-microflora in a continuously fed reactor. The tested HRTs and organic loading rate ranged from 10 to 2 h and 48 to 240 g-COD/l-day, respectively, and the operating pH was 5.5. The experimental results indicate that hydrogen production could not be inhibited under high sulfate concentration and the efficiency was HRT-dependent with a short HRT of 4 h efficiently enhanced hydrogen production. At this HRT the biogas production rate and hydrogen gas content peaked with the hydrogen yield, hydrogen production rate and specific hydrogen production rate of 4.70 mol-H{sub 2}/mol-sucrose, 874 mmol-H{sub 2}/l-day and 432 mmol-H{sub 2}/g-VSS-day, respectively. These values were 50%, 80% and 300%, respectively, higher than those reported for 12 h HRT at the same sulfate concentration. The metabolite concentration fractions were butyrate 77.3%, acetate 15.6%, ethanol 4.4% and propionate 2.0% and changed to 55%, 27.3%, 11.2% and 6.5%, respectively, at HRT 2 h. Therefore, intimate HRT control is important to obtain efficient hydrogen production. Based on a biological growth comparison, pH 5.5 was considered to be the optimal value for operating a hydrogen-producing fermenter fed on sulfate-rich substrate. (author)

  16. Building a parabolic solar concentrator prototype

    Energy Technology Data Exchange (ETDEWEB)

    Escobar-Romero, J F M; Montiel, S Vazquez y; Granados-AgustIn, F; Rodriguez-Rivera, E; Martinez-Yanez, L [INAOE, Luis Enrique Erro 1, Tonantzintla, Pue., 72840 (Mexico); Cruz-Martinez, V M, E-mail: [Universidad Tecnologica de la Mixteca, Camino a Acatilma Km 2.5, Huajuapan de Leon, Oax., 69000 (Mexico)


    In order to not further degrade the environment, people have been seeking to replace non-renewable natural resources such as fossil fuels by developing technologies that are based on renewable resources. An example of these technologies is solar energy. In this paper, we show the building and test of a solar parabolic concentrator as a prototype for the production of steam that can be coupled to a turbine to generate electricity or a steam engine in any particular industrial process.

  17. Concentration of Resources and Economic Growth

    Directory of Open Access Journals (Sweden)

    David Castells-Quintana


    Full Text Available In this letter I summarise the main results and contributions from my Ph.D. thesis on concentration of resources and economic development. The empirical analysis performed in the thesis, and summarised here, focuses on two mayor world trends in modern economic development, namely increasing agglomeration and rising inequalities within countries. In particular, the impact of both trends on long-run economic growth is studied, and results are discussed in light of relevant policy debate.

  18. Concentration curves, inequality and tax reform


    Madden, David


    This paper applies the concept of welfare dominance using concentration curves to household data for Ireland. It identifies marginal tax reforms which would be welfare-enhancing for all social welfare functions satisfying weak restrictions. It also examines cases where stronger restrictions need to be imposed on the social welfare function to yield dominance. These stronger restrictions which we label limited third degree stochastic dominance extends the range of welfare-enhancing marginal ta...

  19. A Review of Solar Photovoltaic Concentrators


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


    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...

  20. Rennet coagulation of heated milk concentrates


    Schreiber, Regina; Hinrichs, Jörg


    International audience; The high temperature heating of cheese milk is a useful tool for preventing late fermentation during cheese ripening if the renneting properties remain unchanged. The aim of the investigations was to find heating conditions which guarantee the inactivation of clostridia spores but still enable rennet coagulation of the heated milk and milk concentrates respectively. The gel strength of the rennet gels increased the more the casein content increased. The native whey pro...

  1. 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


    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.

  2. Concentration-Independent Spontaneously Forming Biomimetric Vesicles (United States)

    Nieh, M.-P.; Harroun, T. A.; Raghunathan, V. A.; Glinka, C. J.; Katsaras, J.


    In this Letter we present small-angle neutron scattering data from a biomimetic system composed of the phospholipids dimyristoyl and dihexanoyl phosphorylcholine (DMPC and DHPC, respectively). Doping DMPC-DHPC multilamellar vesicles with either the negatively charged lipid dimyristoyl phosphorylglycerol (DMPG, net charge -1) or the divalent cation, calcium (Ca2+), leads to the spontaneous formation of energetically stabilized monodisperse unilamellar vesicles whose radii are concentration independent and in contrast with previous experimental observations.

  3. Oscillations of a string with concentrated masses

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, B J [Instituto de Fisica Rosario (CONICET-UNR), Bv. 27 de Febrero 210 Bis, 2000 Rosario (Argentina); Repetto, C E [Instituto de Fisica Rosario (CONICET-UNR), Bv. 27 de Febrero 210 Bis, 2000 Rosario (Argentina); Stia, C R [Instituto de Fisica Rosario (CONICET-UNR), Bv. 27 de Febrero 210 Bis, 2000 Rosario (Argentina); Welti, R [Dto. de Fisica, Esc. de Formacion Basica, Facultad de Ciencias Exactas, IngenierIa y Agrimensura, Universidad Nacional de Rosario, Av. Pellegrini 250, 2000 Rosario (Argentina)


    In this work, the oscillations of a homogeneous string fixed at both ends, and loaded with a finite number of masses, are studied. Through a simple device, the cases with one and two concentrated masses are analysed in detail. The normal modes are observed and the corresponding frequencies are recorded. The experimental results and the solutions of the wave equation that satisfy suitable boundary conditions are compared. The theoretical and experimental results are in very good agreement.

  4. Multilayer reflective coating for solar energy concentrators

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, Perla; Almanza, Rafael [Inst. de Ingenieria, Univ. Nacional Autonoma de Mexico, Mexico (Mexico); Cruz-Manjarrez, Hector [Inst. de Fisica, Univ. Nacional Autonoma de Mexico, Mexico (Mexico)


    The central objective of this work is determine the optimal parameters for the preparation of compound mirrors of first surface of high reflectance by the magnetron sputtering method that will have a direct application in parabolic trough solar concentrators to use in a hybrid solar-geothermal Geothermal Plant at Cerro Prieto, located to the South-eastern of Mexicali City at the Northwest of Mexico. (orig.)

  5. Neutral thermospheric temperature from ion concentration measurements (United States)

    Breig, E. L.; Donaldson, J. S.; Hanson, W. B.; Hoffman, J. H.; Power, R. A.; Kayser, D. C.; Spencer, N. W.; Wharton, L. E.


    A technique for extracting information on neutral temperature from in situ F region measurements of O(+) and H(+) ion concentrations is analyzed and evaluated. Advantage is taken of the condition of charge-exchange equilibrium of these species in the neighborhood of 320 km to infer the associated relative abundances of neutral oxygen and hydrogen. Results are shown to be generally consistent with other concurrent in situ measurements.

  6. Step tracking program for concentrator solar collectors (United States)

    Ciobanu, D.; Jaliu, C.


    The increasing living standards in developed countries lead to increased energy consumption. The fossil fuel consumption and greenhouse gas effect that accompany the energy production can be reduced by using renewable energy. For instance, the solar thermal systems can be used in temperate climates to provide heating during the transient period or cooling during the warmer months. Most used solar thermal systems contain flat plate solar collectors. In order to provide the necessary energy for the house cooling system, the cooling machine uses a working fluid with a high temperature, which can be supplied by dish concentrator collectors. These collectors are continuously rotated towards sun by biaxial tracking systems, process that increases the consumed power. An algorithm for a step tracking program to be used in the orientation of parabolic dish concentrator collectors is proposed in the paper to reduce the consumed power due to actuation. The algorithm is exemplified on a case study: a dish concentrator collector to be implemented in Brasov, Romania, a location with the turbidity factor TR equal to 3. The size of the system is imposed by the environment, the diameter of the dish reflector being of 3 meters. By applying the proposed algorithm, 60 sub-programs are obtained for the step orientation of the parabolic dish collector over the year. Based on the results of the numerical simulations for the step orientation, the efficiency of the direct solar radiation capture on the receptor is up to 99%, while the energy consumption is reduced by almost 80% compared to the continuous actuation of the concentrator solar collector.

  7. Multiphoton entanglement concentration and quantum cryptography. (United States)

    Durkin, Gabriel A; Simon, Christoph; Bouwmeester, Dik


    Multiphoton states from parametric down-conversion can be entangled both in polarization and photon number. Maximal high-dimensional entanglement can be concentrated postselectively from these states via photon counting. This makes them natural candidates for quantum key distribution, where the presence of more than one photon per detection interval has up to now been considered undesirable. We propose a simple multiphoton cryptography protocol for the case of low losses.

  8. Photovoltaic concentrator assembly with optically active cover (United States)

    Plesniak, Adam P


    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.

  9. White butterflies as solar photovoltaic concentrators (United States)

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


    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.

  10. Microfluidic distillation chip for methanol concentration detection. (United States)

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


    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.

  11. Hyaluronic acid concentration in liver diseases. (United States)

    Gudowska, Monika; Gruszewska, Ewa; Panasiuk, Anatol; Cylwik, Bogdan; Flisiak, Robert; Świderska, Magdalena; Szmitkowski, Maciej; Chrostek, Lech


    The aim of this study was to evaluate the effect of liver diseases of different etiologies and clinical severity of liver cirrhosis on the serum level of hyaluronic acid. The results were compared with noninvasive markers of liver fibrosis: APRI, GAPRI, HAPRI, FIB-4 and Forn's index. Serum samples were obtained from 20 healthy volunteers and patients suffering from alcoholic cirrhosis (AC)-57 patients, non-alcoholic cirrhosis (NAC)-30 and toxic hepatitis (HT)-22. Cirrhotic patients were classified according to Child-Pugh score. Hyaluronic acid concentration was measured by the immunochemical method. Non-patented indicators were calculated using special formulas. The mean serum hyaluronic acid concentration was significantly higher in AC, NAC and HT group in comparison with the control group. There were significant differences in the serum hyaluronic acid levels between liver diseases, and in AC they were significantly higher than those in NAC and HT group. The serum hyaluronic acid level differs significantly due to the severity of cirrhosis and was the highest in Child-Pugh class C. The sensitivity, specificity, accuracy, positive and negative predictive values and the area under the ROC curve for hyaluronic acid and all non-patented algorithms were high and similar to each other. We conclude that the concentration of hyaluronic acid changes in liver diseases and is affected by the severity of liver cirrhosis. Serum hyaluronic acid should be considered as a good marker for noninvasive diagnosis of liver damage, but the combination of markers is more useful.

  12. Concentration dependent hydrogen diffusion in tungsten (United States)

    Ahlgren, T.; Bukonte, L.


    The diffusion of hydrogen in tungsten is studied as a function of temperature, hydrogen concentration and pressure using Molecular Dynamics technique. A new analysis method to determine diffusion coefficients that accounts for the random oscillation of atoms around the equilibrium position is presented. The results indicate that the hydrogen migration barrier of 0.25 eV should be used instead of the presently recommended value of 0.39 eV. This conclusion is supported by both experiments and density functional theory calculations. Moreover, the migration volume at the saddle point for H in W is found to be positive: ΔVm ≈ 0.488 Å3, leading to a decrease in the diffusivity at high pressures. At high H concentrations, a dramatic reduction in the diffusion coefficient is observed, due to site blocking and the repulsive H-H interaction. The results of this study indicates that high flux hydrogen irradiation leads to much higher H concentrations in tungsten than expected.

  13. Low concentration ratio solar array structural configuration (United States)

    Nalbandian, S. J.


    The design and structural properties of a low concentration ratio solar array are discussed. The assembled module consists of six interconnected containers which are compactly stowed in a volume of 3.24 m(3) for delivery to orbit by the shuttle. The containers deploy in accordian fashion into a rectangular area of 19.4 x 68 meters and can be attached to the user spacecraft along the longitudinal centerline of the end container housing. Five rotary incremental actuators requiring about 8 watts each will execute the 180-degree rotation at each joint. Deployable masts (three per side) are used to extend endcaps from the housing in both directions. Each direction is extended by three masts requiring about 780 watts for about 27 minutes. Concentrator elements are extended by the endcaps and are supported by cable systems that are connected between the housings and endcaps. These power generating elements contain reflector panels which concentrate light onto the solar panels consisting of an aluminum radiator with solar cells positioned within the element base formed by the reflectors. A flat wire harness collects the power output of individual elements for transfer to the module container housing harnesses.


    Directory of Open Access Journals (Sweden)

    Aurelia Ionescu


    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.

  15. Local transient rheological behavior of concentrated suspensions

    CERN Document Server

    Blanc, Frédéric; Lemaire, Elisabeth


    This paper reports experiments on the shear transient response of concentrated non-Brownian suspensions. The shear viscosity of the suspensions is measured using a wide-gap Couette rheometer equipped with a Particle Image Velocimetry (PIV) device that allows measuring the velocity field. The suspensions made of PMMA particles (31$\\mu$m in diameter) suspended in a Newtonian index- and density-matched liquid are transparent enough to allow an accurate measurement of the local velocity for particle concentrations as high as 50%. In the wide-gap Couette cell, the shear induced particle migration is evidenced by the measurement of the time evolution of the flow profile. A peculiar radial zone in the gap is identified where the viscosity remains constant. At this special location, the local particle volume fraction is taken to be the mean particle concentration. The local shear transient response of the suspensions when the shear flow is reversed is measured at this point where the particle volume fraction is well ...

  16. A Wall of Funnels Concentrates Swimming Bacteria▿ (United States)

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


    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 concentration of nonswimming cells. Similarly, we show that a series of such funnel walls functions as a multistage pump and can increase the concentration of motile bacteria exponentially with the number of walls. The funnel wall can be arranged along arbitrary shapes and cause the bacteria to form well-defined patterns. The funnel effect may also have implications on the transport and distribution of motile microorganisms in irregular confined environments, such as porous media, wet soil, or biological tissue, or act as a selection pressure in evolution experiments. PMID:17890308

  17. Postnatal Testosterone Concentrations and Male Social Development

    Directory of Open Access Journals (Sweden)

    Gerianne M Alexander


    Full Text Available Converging evidence from over 40 years of behavioral research indicates that higher testicular androgens in prenatal life and at puberty contribute to the masculinization of human behavior. However, the behavioral significance of the transient activation of the hypothalamic-pituitary-gonadal (HPG axis in early postnatal life remains largely unknown. Although early research on nonhuman primates indicated suppression of the postnatal surge in testicular androgens had no measurable effects on the later expression of the male behavioral phenotype, recent research from our laboratory suggests that postnatal testosterone concentrations influence male infant preferences for larger social groups and temperament characteristics associated with the later development of aggression. In later assessment of gender-linked behavior in the second year of life, concentrations of testosterone at 3-4 months of age were unrelated to toy choices and activity levels during toy play. However, higher concentrations of testosterone predicted less vocalization in toddlers and higher parental ratings on an established screening measure for autism spectrum disorder. These findings suggest a role of the transient activation of the HPG axis in the development of typical and atypical male social relations and suggest that it may be useful in future research on the exaggerated rise in testosterone secretion in preterm infants or exposure to hormone disruptors in early postnatal life to include assessment of gender-relevant behavioral outcomes, including childhood disorders with sex-biased prevalence rates.

  18. Estimating atmospheric mercury concentrations with lichens. (United States)

    Vannini, Andrea; Nicolardi, Valentina; Bargagli, Roberto; Loppi, Stefano


    The uptake kinetics of elemental gaseous Hg (Hg(0)) in three species of epiphytic lichens (Pseudevernia furfuracea, Evernia prunastri, and Xanthoria parietina) were investigated under four different Hg concentrations (10, 15, 30, and 45 μg/m(3)) and three different temperatures (10, 20, and 30 °C) with the aim of evaluating the lichen efficiency for Hg(0) accumulation and their potential use in the estimate of atmospheric concentrations of this metal in the field. The results showed that under our experimental conditions the lichens accumulated Hg according to exposure time and that the metal is not released back to the atmosphere after Hg(0) was removed from the air (clearance). Pseudevernia furfuracea showed the highest Hg accumulation capacity and Evernia prunastri showed the lowest, but in these species the metal uptake kinetics was affected by temperature. Xanthoria parietina showed an intermediate metal accumulation capacity and a Hg accumulation rate independent of temperature (in the range 10-30 °C). The use of first-order kinetics equations for Hg uptake in X. parietina and available field data on Hg bioaccumulation in this species allowed reliable estimates of atmospheric Hg concentrations in the environment.

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

    Directory of Open Access Journals (Sweden)

    J. S. Pruthi


    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."

  20. A decomposing technique for scheelite concentrate and low-grade scheelite concentrate

    Institute of Scientific and Technical Information of China (English)

    HUO Guangsheng; SUN Peimei; LI Honggui; LI Yunjiao; ZHAO Zhongwei; SUN Zhaoming; LIU Maosheng


    The effect of different decomposition conditions on tungsten recovery for scheelite concentrate has been examined. The results show that tungsten recovery can be more than 98% under decomposing conditions as follows: the amount of caustic soda is 2.2 and 3.2 times of theoretical respectively, ratio of water and ore is 0.7-0.8, temperature is 160℃, and preservation time is 2.0 h for scheelite concentrate (63.21% WO3) and low grade scheelite concentrate (55.17% WO3).

  1. Fluorescence lifetime to image epidermal ionic concentrations (United States)

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


    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.

  2. Energy gap in concentrated spin glasses

    Energy Technology Data Exchange (ETDEWEB)

    Liao, S.B.; Bhagat, S.M.; Manheimer, M.A.; Moorjani, K.


    Using magnetic resonance data at several frequencies, we have obtained the temperature dependence of the field-induced magnetization (M) in three concentrated spin glasses. At every frequency, M is independent of T for Tapprox.

  3. Solar simulator for concentrator photovoltaic systems. (United States)

    Domínguez, César; Antón, Ignacio; Sala, Gabriel


    A solar simulator for measuring performance of large area concentrator photovoltaic (CPV) modules is presented. Its illumination system is based on a Xenon flash light and a large area collimator mirror, which simulates natural sun light. Quality requirements imposed by the CPV systems have been characterized: irradiance level and uniformity at the receiver, light collimation and spectral distribution. The simulator allows indoor fast and cost-effective performance characterization and classification of CPV systems at the production line as well as module rating carried out by laboratories.

  4. Concentrated sunlight for organic solar cells

    DEFF Research Database (Denmark)

    Tromholt, Thomas


    studies of polymers for organic solar cells. Degradation was monitored by the evolution of the UV-vis absorption over time. Varying the solar intensity from 1 to 200 suns, the degradation rates were increased by more than a factor of 100 relative to degradation at 1 simulated sun. 5 different 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....

  5. Double curvature mirrors for linear concentrators (United States)

    Lance, Tamir; Ackler, Harold; Finot, Marc


    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.

  6. Advertising and concentration in the brewing industry

    DEFF Research Database (Denmark)

    Madsen, Erik Strøjer; Wu, Yanqing

    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......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...

  7. Irreversible adsorption from concentrated polymer solutions (United States)

    Auvray, Loïc; Cruz, Margerida; Auroy, Philippe


    We study the adsorption of concentrated Poly(dimethylsiloxane) (PDMS) solutions in Dichloromethane on porous silica. We vary the plymerization index N and the chain volume fraction Φ from the overlap concentration to the melt. The adsorption of PDMS on silica by hydrogen bonding is very strong and a large amount of polymer remains bound to the surface after the washing of the silica with a good solvent of the chains. We measure this quantity Γ by small angle neutron scattering. If there is no chain desorption, Γ represents the weight of polymer attached to the solid in the initial solution, which varies as the product N^{1/2} Φ^{7/8} according to a recent prediction. This relation of proportionality indeed interprets our experimental results. When the size of the chains is comparable to the pore diameter (either 500, 1 200, or 3 000 Å depending on the samples) we observe confinement effects which lower the adsorbed amount. Nous étudions d'adsorption de solutions concentrées de Poly(dimethylsiloxane) (PDMS) dans le chlorure de méthylène sur de la silice poreuse. Nous varions le degré de polymérisation N et la fraction volumique Φ des chaînes depuis la concentration de recouvrement jusqu'au fondu. L'adsorption de PDMS sur la silice par liaison hydrogène est très forte et une grande quantité de polymère reste liée à la surface après lavage de la silice par du bon solvant. Nous mesurons cette quantité Γ par diffusion centrale des neutrons. S'il n'y a pas eu désorption des chaînes, Γ représente le poids de polymère attaché au solide dans la solution initiale qui varie selon une prédiction récente comme le produit N^{1/2} Φ^{7/8}. Cette relation de proportionnalité rend effectivement compte de nos résultats. Quand la taille des chaînes est du même ordre de grandeur que le diamètre des pores (qui prend les valeurs 500, 1 200 et 3 000 Å selon les échantillons), nous observons des effets de confinement abaissant la quantité adsorbée.

  8. Optical measurement of drug concentrations in tissue

    Energy Technology Data Exchange (ETDEWEB)

    Mourant, J.R.; Bigio, I.J.; Jack, D.A.; Johnson, T.M.; Miller, H.D. [Los Alamos National Lab., NM (United States). Chemical Sciences and Technology Div.


    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The aim of this project was to develop noninvasive fiber-optic methods for measuring drug concentrations in tissue. Such a system would make possible the study of chemotherapy drug kinetics at specific, targeted locations in the body after the drug is administered. The major result of this project is the development of techniques for measuring changes in absorption of a medium with unknown scattering properties. The developed method was verified by testing on several media with scattering properties in the range typically found for tissue.

  9. Particulate Concentration Levels in Chinatown, Oakland, California (United States)

    Chen, B.; Yeung, A.; Yu, J. F.


    Chinatown is located near the center of the busy business district of downtown Oakland, California. It is one of the most inhabited and congested areas in the City of Oakland, averaging 4,000 vehicles and 3,000 pedestrians per hour at a key intersection in the center of the neighborhood. Particles produced by automobiles and construction can settle into the bronchi of lungs and induce asthma attacks, irritate cardiovascular tissue, and possibly lead to lung cancer and death. Particulate pollution is a serious problem that is estimated to cause between 20,000 and 50,000 deaths per year in the US alone. Hence, evaluation of the air quality of the Chinatown neighborhood is important, because it helps to address issues that are of great concern to residents of the area. The primary goal of our project was to measure particulate concentration levels at various intersections in Oakland's Chinatown to determine if the air quality met U.S. EPA standards, and to take note of any trends that may occur over a period of months. We were primarily concerned with particles that are 2.5 micrometers diameter and smaller, as smaller particles are easily inhaled and directly affect the respiratory system. We were interested in identifying any intersections that may have had significantly higher levels than other intersections. Using a map of Chinatown, we chose 12 intersections and made measurements at these points over the course of six months, beginning in February and ending in July of 2007. Particulate matter measurements were made using a FLUKE 893 Particle Counter. Measurements recorded on the first day of our study, February 4, 2007, which was the day of an annual street festival, yielded the highest values for particulate matter concentration in our dataset. This was followed by a significant drop in concentration the following week, and then a gradual increase of concentration as the months progressed. No one location yielded values significantly higher than any other, and

  10. A Novel Method for Detergent Concentration Determination


    Kaufmann, Thomas C.; Engel, Andreas; Rémigy, Hervé-W.


    A fast and precise method for detergent concentration determination is presented. (Patent applications for the method described here have been submitted (EP05011904 and US60/702,261). Depending on the interest of the scientific community, the system will be commercialized. (For further information contact Hervé-W. Rémigy at the e-mail address below.) A small droplet of the detergent solution is deposited on a piece of Parafilm M and side views are recorded by two orthogonally arranged TV came...

  11. Suspension Hydrogen Reduction of Iron Oxide Concentrates

    Energy Technology Data Exchange (ETDEWEB)

    H.Y. Sohn


    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.

  12. Computer simulation of concentrated solid solution strengthening (United States)

    Kuo, C. T. K.; Arsenault, R. J.


    The interaction forces between a straight edge dislocation moving through a three-dimensional block containing a random array of solute atoms were determined. The yield stress at 0 K was obtained by determining the average maximum solute-dislocation interaction force that is encountered by edge dislocation, and an expression relating the yield stress to the length of the dislocation and the solute concentration is provided. The magnitude of the solid solution strengthening due to solute atoms can be determined directly from the numerical results, provided the dislocation line length that moves as a unit is specified.

  13. 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


    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. Late...... of HCG administration and the probability of clinical pregnancy in women undergoing ovarian stimulation with GnRH agonists and gonadotrophins for assisted reproduction treatment.Instead, late-follicular-phase progesterone concentration appears to be governed by the number of preovulatory follicles and LH...

  14. Equilibrium concentrations for pyruvate dehydrogenase and the citric acid cycle at specified concentrations of certain coenzymes. (United States)

    Alberty, Robert A


    It is of interest to calculate equilibrium compositions of systems of biochemical reactions at specified concentrations of coenzymes because these reactants tend to be in steady states. Thermodynamic calculations under these conditions require the definition of a further transformed Gibbs energy G" by use of a Legendre transform. These calculations are applied to the pyruvate dehydrogenase reaction plus the citric acid cycle, but steady-state concentrations of CoA, acetyl-CoA and succinyl-CoA cannot be specified because they are involved in the conservation of carbon atoms. These calculations require the use of linear algebra to obtain further transformed Gibbs energies of formation of reactants and computer programs to calculate equilibrium compositions. At specified temperature, pH, ionic strength and specified concentrations of several coenzymes, the equilibrium composition depends on the specified concentrations of the coenzymes and the initial amounts of reactants.

  15. Optical characterization of nonimaging dish concentrator for the application of dense-array concentrator photovoltaic system. (United States)

    Tan, Ming-Hui; Chong, Kok-Keong; Wong, Chee-Woon


    Optimization of the design of a nonimaging dish concentrator (NIDC) for a dense-array concentrator photovoltaic system is presented. A new algorithm has been developed to determine configuration of facet mirrors in a NIDC. Analytical formulas were derived to analyze the optical performance of a NIDC and then compared with a simulated result obtained from a numerical method. Comprehensive analysis of optical performance via analytical method has been carried out based on facet dimension and focal distance of the concentrator with a total reflective area of 120 m2. The result shows that a facet dimension of 49.8 cm, focal distance of 8 m, and solar concentration ratio of 411.8 suns is the most optimized design for the lowest cost-per-output power, which is US$1.93 per watt.

  16. Design and construction of non-imaging planar concentrator for concentrator photovoltaic system

    Energy Technology Data Exchange (ETDEWEB)

    Chong, K.K.; Siaw, F.L.; Wong, C.W.; Wong, G.S. [Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Off Jalan Genting Kelang, Setapak, 53300 Kuala Lumpur, Wilayah Persekutuan (Malaysia)


    A novel configuration of solar concentrator, which is the non-imaging planar concentrator, capable of producing much more uniform sunlight and reasonably high concentration ratio, is designed and constructed. This design is envisioned to be incorporated in concentrator photovoltaic (CPV) systems. The work presented here reports on the design, optical alignment and application of the prototype, which is installed at Universiti Tunku Abdul Rahman (UTAR), Malaysia. In the architecture of the prototype, 360 flat mirrors, each with a dimension of 4.0 cm x 4.0 cm, are arranged into 24 rows and 15 columns with a total reflection area of about 5760 cm{sup 2}. In addition to that, illumination distribution for the prototype is simulated and its results are then compared with the experiment result. (author)

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

    KAUST Repository

    Zhang, Ji


    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

  18. Hair and toenail arsenic concentrations of residents living in areas with high environmental arsenic concentrations.


    Hinwood, Andrea L; Sim, Malcolm R; Jolley, Damien; de Klerk, Nick; Bastone, Elisa B; Gerostamoulos, Jim; Drummer, Olaf H


    Surface soil and groundwater in Australia have been found to contain high concentrations of arsenic. The relative importance of long-term human exposure to these sources has not been established. Several studies have investigated long-term exposure to environmental arsenic concentrations using hair and toenails as the measure of exposure. Few have compared the difference in these measures of environmental sources of exposure. In this study we aimed to investigate risk factors for elevated hai...

  19. A Concentrator Photovoltaic System Based on a Combination of Prism-Compound Parabolic Concentrators

    Directory of Open Access Journals (Sweden)

    Ngoc Hai Vu


    Full Text Available We present a cost-effective concentrating photovoltaic system composed of a prism and a compound parabolic concentrator (P-CPC. In this approach, the primary collector consists of a prism, a solid compound parabolic concentrator (CPC, and a slab waveguide. The prism, which is placed on the input aperture of CPC, directs the incoming sunlight beam to be parallel with the main axes of parabolic rims of CPC. Then, the sunlight is reflected at the parabolic rims and concentrated at the focal point of these parabolas. A slab waveguide is coupled at the output aperture of the CPC to collect focused sunlight beams and to guide them to the solar cell. The optical system was modeled and simulated with commercial ray tracing software (LightTools™. Simulation results show that the optical efficiency of a P-CPC can achieve up to 89%. when the concentration ratio of the P-CPC is fixed at 50. We also determine an optimal geometric structure of P-CPC based on simulation. Because of the simplicity of the P-CPC structure, a lower-cost mass production process is possible. A simulation based on optimal structure of P-CPC was performed and the results also shown that P-CPC has high angular tolerance for input sunlight. The high tolerance of the input angle of sunlight allows P-CPC solar concentrator utilize a single sun tracking system instead of a highly precise dual suntracking system as cost effective solution.

  20. Dependency of soil activity concentration on soil -biota concentration ratio of radionuclides for earthworm

    Energy Technology Data Exchange (ETDEWEB)

    Keum, Dong Kwon; Kim, Byeong Ho; Jun, In; Lim, Kwang Muk; Choi, Yong Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)


    The transfer of radionuclides to wildlife (non-human biota) is normally quantified using an equilibrium concentration ratio (CR{sub eq}), defined as the radionuclide activity concentration in the whole organism (fresh weight) divided by that in the media (dry weight for soil). The present study describes the effect of soil radionuclide activity concentration on the transfer of {sup 137}Cs, {sup 85}Sr and {sup 65}Zn to a functionally important wildlife group, annelids, using a commonly studied experimental worm (E.andrei). Time-dependent whole body concentration ratios of {sup 137}Cs, {sup 85}Sr and {sup 65}Zn for the earthworm were experimentally measured for artificially contaminated soils with three different activity concentrations for each radionuclide which were considerably higher than normal background levels. Two parameters of a first order kinetic model, the equilibrium concentration ratio (CR{sub eq}) and the effective loss rate constant (k), were estimated by comparison of experimental CR results with the model prediction

  1. Pollution concentration estimates in ecologically important zones

    Energy Technology Data Exchange (ETDEWEB)

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


    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

  2. Cast Stone Formulation At Higher Sodium Concentrations

    Energy Technology Data Exchange (ETDEWEB)

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


    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

  3. Cast Stone Formulation At Higher Sodium Concentrations

    Energy Technology Data Exchange (ETDEWEB)

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


    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

  4. Direct seawater desalination by ion concentration polarization. (United States)

    Kim, Sung Jae; Ko, Sung Hee; Kang, Kwan Hyoung; Han, Jongyoon


    A shortage of fresh water is one of the acute challenges facing the world today. An energy-efficient approach to converting sea water into fresh water could be of substantial benefit, but current desalination methods require high power consumption and operating costs or large-scale infrastructures, which make them difficult to implement in resource-limited settings or in disaster scenarios. Here, we report a process for converting sea water (salinity approximately 500 mM or approximately 30,000 mg l(-1)) to fresh water (salinity water is divided into desalted and concentrated streams by ion concentration polarization, a phenomenon that occurs when an ion current is passed through ion-selective membranes. During operation, both salts and larger particles (cells, viruses and microorganisms) are pushed away from the membrane (a nanochannel or nanoporous membrane), which significantly reduces the possibility of membrane fouling and salt accumulation, thus avoiding two problems that plague other membrane filtration methods. To implement this approach, a simple microfluidic device was fabricated and shown to be capable of continuous desalination of sea water (approximately 99% salt rejection at 50% recovery rate) at a power consumption of less than 3.5 Wh l(-1), which is comparable to current state-of-the-art systems. Rather than competing with larger desalination plants, the method could be used to make small- or medium-scale systems, with the possibility of battery-powered operation.

  5. Simulation of an electrowetting solar concentration cell (United States)

    Khan, Iftekhar; Rosengarten, Gary


    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.

  6. Armoring confined bubbles in concentrated colloidal suspensions (United States)

    Yu, Yingxian; Khodaparast, Sepideh; Stone, Howard


    Encapsulation of a bubble with microparticles is known to significantly improve the stability of the bubble. This phenomenon has recently gained increasing attention due to its application in a variety of technologies such as foam stabilization, drug encapsulation and colloidosomes. Nevertheless, the production of such colloidal armored bubble with controlled size and particle coverage ratio is still a great challenge industrially. We study the coating process of a long air bubble by microparticles in a circular tube filled with a concentrated microparticles colloidal suspension. As the bubble proceeds in the suspension of particles, a monolayer of micro-particles forms on the interface of the bubble, which eventually results in a fully armored bubble. We investigate the phenomenon that triggers and controls the evolution of the particle accumulation on the bubble interface. Moreover, we examine the effects of the mean flow velocity, the size of the colloids and concentration of the suspension on the dynamics of the armored bubble. The results of this study can potentially be applied to production of particle-encapsulated bubbles, surface-cleaning techniques, and gas-assisted injection molding.

  7. Multiband solar concentrator using transmissive dichroic beamsplitting (United States)

    Karp, Jason H.; Ford, Joseph E.


    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.

  8. Cast Stone Formulation At Higher Sodium Concentrations

    Energy Technology Data Exchange (ETDEWEB)

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


    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

  9. NO concentration imaging in turbulent nonpremixed flames

    Energy Technology Data Exchange (ETDEWEB)

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


    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.


    Energy Technology Data Exchange (ETDEWEB)



    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.

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

    NARCIS (Netherlands)

    De Boer, D.K.G.


    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.

  12. Sedimentary cobalt concentrations track marine redox evolution (United States)

    Swanner, Elizabeth; Planavsky, Noah; Lalonde, Stefan; Robbins, Jamie; Bekker, Andrey; Rouxel, Olivier; Konhauser, Kurt O.; Mojzsis, Stephen J.


    Oxygen production by photosynthesis drove the redox evolution of the atmosphere and ocean. Primary productivity by oxygenic photosynthesizers in the modern surface ocean is limited by trace nutrients such as iron, but previous studies have also observed high Co uptake associated with natural cyanobacterial populations. Constraining the size and variation of the oceanic reservoir of Co through time will help to understand the regulation of primary productivity and hence oxygenation through time. In this study, Co concentrations from iron formations (IF), shales and marine pyrites deposited over nearly 4 billion years of Earth's history are utilized to reconstruct secular changes in the mechanisms of Co removal from the oceanic reservoir. The Co reservoir prior to ~2 Ga was dominated by hydrothermal inputs and Fe(III)oxyhydroxides were likely involved in the removal of Co from the water column. Fe(II) oxidation in the water column resulted in the deposition of IF in the Archean and Paleoproterozoic, and the Co inventory of IF records a large oceanic reservoir of Co during this time. Lower Co concentrations in sediments during the Middle Proterozoic signify a decrease in the oceanic reservoir due to the expansion euxinic environments, corresponding to the results of previous studies. A transition to an oxidized deep ocean in the Phanerozoic is evidenced by correlation between Co and manganese (Mn) concentrations in hydrothermal and exhalative deposits, and in marine pyrites. This relationship between Co and Mn, signifying deposition of Co in association with Mn(IV)oxides, does not occur in the Precambrian. Mn(II) oxidation occurs at higher redox potentials than that required for Fe(II) oxidation, and the extent of Mn redox cycling prior to full ventilation of the oceans at the end of the Neoproterozoic was likely limited to spatially restricted oxic surface waters. In this regard, Co is another valuable redox proxy for tracking the growth and decline in oxygenated

  13. Flow line asymmetric nonimaging concentrating optics (United States)

    Jiang, Lun; Winston, Roland


    Nonimaging Optics has shown that it achieves the theoretical limits by utilizing thermodynamic principles rather than conventional optics. Hence in this paper the condition of the "best" design are both defined and fulfilled in the framework of thermodynamic arguments, which we believe has profound consequences for the designs of thermal and even photovoltaic systems, even illumination and optical communication tasks. This new way of looking at the problem of efficient concentration depends on probabilities, geometric flux field and radiative heat transfer while "optics" in the conventional sense recedes into the background. Some of the new development of flow line designs will be introduced and the connection between the thermodynamics and flow line design will be officially formulated in the framework of geometric flux field. A new way of using geometric flux to design nonimaging optics will be introduced. And finally, we discuss the possibility of 3D ideal nonimaing optics.

  14. Luminescent solar concentrator improvement by stimulated emission (United States)

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


    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.

  15. Luminescent solar concentrators utilizing stimulated emission. (United States)

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


    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.

  16. Mechanically stacked concentrator tandem solar cells (United States)

    Andreev, V. M.; Rumyantsev, V. D.; Karlina, L. B.; Kazantsev, A. B.; Khvostikov, V. P.; Shvarts, M. Z.; Sorokina, S. V.


    Four-terminal mechanically stacked solar cells were developed for advanced space arrays with line-focus reflective concentrators. The top cells are based on AlGaAs/GaAs multilayer heterostructures prepared by low temperature liquid phase epitaxy. The bottom cells are based on heteroepitaxial InP/InGaAs liquid phase epitaxy or on homo-junction GaSb, Zn-diffused structures. The sum of the highest reached efficiencies of the top and bottom cells is 29.4 percent. The best four-terminal tandems have an efficiency of 27 to 28 percent. Solar cells were irradiated with 1 MeV electrons and their performances were determined as a function of fluence up to 10(exp 16) cm(exp-2). It was shown that the radiation resistance of developed tandem cells is similar to the most radiative stable AlGaAs/GaAs cells with a thin p-GaAs photoactive layer.

  17. Towards a flat 45%-efficient concentrator module

    Energy Technology Data Exchange (ETDEWEB)

    Mohedano, Rubén, E-mail:; 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)


    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.

  18. Assays for Determination of Protein Concentration. (United States)

    Olson, Bradley J S C


    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.

  19. Magnetohydrodynamic Flow Between Concentric Rotating Porous Cylinders

    Directory of Open Access Journals (Sweden)

    S. N. Dube


    Full Text Available An attempt has been made to study the steady laminar flow of a incompressible electrically conducting fluid between infinitely long concentric rotating porous cylinders under the influence of radial magnetic field. A solution has been obtained under the assumption of uniform conditions along the axis of the cylinders. The cylinders being porous, a hyperbolic radial velocity distribution has been superimposed over the circumferential velocity produced due to rotation. There is a Bernoulli type pressure variation in the radial in the direction. When the inner cylinder is at rest the shearing stress at it and the torque transmitted to it decrease as R (=v/Sub/1y/Sub1/v= v/Sub2y/Sub2/v increases and the magnetic parameter lambda (=4sigma mue/sube/sup2A/Sup2/Mue will further decrease them.

  20. Concentration Distribution in a Mixing Ventilated Room

    DEFF Research Database (Denmark)

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


    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......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 ensure that the ventilation system meets the demands it is important to know which parameters that influence the performance of the system. In this work the mixing ventilation principle was investigated. When the mixing ventilation principle is used for the design of a ventilation system it is assumed...

  1. Chloromethylation of asphyalthene concentrates of petroleum

    Energy Technology Data Exchange (ETDEWEB)

    Pokonova, Yu.V.; Proskuryakov, V.A.; Ashirov, A.; Mitrofanova, L.M.


    It was shown that chloromethylation of asphalthene concentrates is an extremely rapid reaction with a low energy barrier; polychloromethyl derivatives contain 16 to 30% chlorine. The activity of Friedel-Krafts catalysts in chloromethylation and the competing reaction of condensation of chloromethyl derivatives decreases in the order FeCl/sub 3/ > ZnCl/sub 2/ > SnCl/sub 2/ > SnCl/sub 4/ > AlCl/sub 3/ > TiCl/sub 3/ > TiCl/sub 4/ > SbCl/sub 3/ > SbCl/sub 5/. Strong and weak basic anion-exchange resins (powdered) were obtained by amination of chloromethylated products, these resins having a considerable rate of ion-exchange, high dynamic, kinetic characteristics and high radiation resistance. 2 figures, 2 tables.

  2. Entanglement Concentration with Quantum Non Demolition Hamiltonians

    CERN Document Server

    Tatham, Richard


    We devise and examine two procrustean entanglement concentration schemes using Quantum Non- Demolition (QND) interaction Hamiltonians in the continuous variable regime, applicable for light, for atomic ensembles or in a hybrid setting. We thus expand the standard entanglement distillation toolbox to the use of a much more general, versatile and experimentally feasible interaction class. The first protocol uses Gaussian ancillary modes and a non-Gaussian post-measurement, the second a non-Gaussian ancillary mode and a Gaussian post-measurement. We explicitly calculate the density matrix elements of the non-Gaussian mixed states resulting from these protocols using an elegant Wigner-function based method in a numerically efficient manner. We then quantify the entanglement increase calculating the Logarithmic Negativity of the output state and discuss and compare the performance of the protocols.


    Directory of Open Access Journals (Sweden)

    M. Ghiasseddin


    Full Text Available Hazards of soluable hexa and trivalent chromium have been documented by many investigators. But there was no information regarding safety of about 5000 workers at exposure risk to chromium in 600 primitive electroplating work shops of Tehran. During this study more than 70% of work shops were inactive due to some of their own problems. Out of active plants those that were relatively more cooperative 43 manual and 3 semi automatic were investigated for chromium concentration both by personal and environmental Sampling. The Samples were analyzed by AAS and cholormetry. In 30% of personal and 40% of environmental samples both total and Cr+6 were higher than ACGIH’S TLV. In one of semiautomatic plant Cr=6 was as high as 0.71 mg/m.3.Regarding injuries, following observations were made: Nasal wound 85%, skin irritation 73% , Dermatitis 35% and some other chromium related injuries including 2 cases of Septum perforations.

  4. Inverse Kinematics of Concentric Tube Steerable Needles (United States)

    Sears, Patrick; Dupont, Pierre E.


    Prior papers have introduced steerable needles composed of precurved concentric tubes. The curvature and extent of these needles can be controlled by the relative rotation and translation of the individual tubes. Under certain assumptions on the geometry and design of these needles, the forward kinematics problem can be solved in closed form by means of algebraic equations. The inverse kinematics problem, however, is not as straightforward owing to the nonlinear map between relative tube displacements and needle tip configuration as well as to the multiplicity of solutions as the number of tubes increases. This paper presents a general approach to solving the inverse kinematics problem using a pseudoinverse solution together with gradients of nullspace potential functions to enforce geometric and mechanical constraints. PMID:23685532

  5. Whey protein concentrate market enhancement. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, L.


    Whey protein concentrate (WPC) was studied to see whether or not there was sufficient depth in the marketplace to accommodate increased WPC production in the event more whey was converted into alcohol. It was concluded that the current market for WPC is still immature and ample room exists in the marketplace to produce and dispose of WPC. In addition, WPC literature was reviewed so as to evaluate the current state of the art producing WPC. Considerable evidence suggests that more product formulation work is needed to move WPC into the general marketplace. Concurrent to the market and ltierature study WPC was incorporated into select categories of foods where finished goods were enhanced by having WPC incorporated in their formulations. Formulations were produced to demonstrate the fact that products such as ice cream, breedings and batters for fish sticks, and orange juice can be enhanced by using WPC.

  6. Glass integrated nanochannel waveguide for concentration measurements (United States)

    Jardinier, E.; Bucci, D.; Couston, L.; Canto, F.; Magnaldo, A.; Broquin, J.-E.


    We present a new integrated optical sensor for absorption spectroscopy in a hostile environment, based on a nanochannel waveguide structure in glass. The nanochannel waveguide is made by bonding two ion-exchanged borosilicate glass wafers, one of them being etched by reactive ion etching to create a 100 nm deep fluidic channel. Typical fluid/light interaction factors of 2.3 % can be achieved inside a 7.4 pL volume of fluid, over a 550 nm bandwidth, surmounting evanescent wave sensors in terms of confinement efficiency and allowing spectrometric measurements. Absorption measurements have been performed on hexahydrate neodymium nitrate in nitric acid solutions of various concentrations leading to a minimum detectable absorption coefficient of 0.57 cm-1, which can be further decreased by implementing low bending-loss spiral-like nanochannel waveguides.

  7. Increased plasma fibronectin concentrations in obesity

    DEFF Research Database (Denmark)

    Andersen, T; Dejgaard, A; Astrup, A


    treated with an intermittent very-low-calorie formula diet sufficient in respect to protein, minerals and vitamins. They were investigated in weight-stable states. Before weight reduction, 14 patients (61%, 95% confidence limits 39-80%) had elevated plasma fibronectin levels. Plasma fibronectin decreased......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...... (medians 1.22 and 0.59 mumol/l before and after weight loss, p less than 0.01) and was after weight loss within the normal range in 14 patients. The change in plasma fibronectin was unassociated with the magnitude of the weight loss as well as with the reduction of overweight. The resulting plasma...

  8. Concentration Dependent Structure of Block Copolymer Solutions (United States)

    Choi, Soohyung; Bates, Frank S.; Lodge, Timothy P.


    Addition of solvent molecules into block copolymer can induce additional interactions between the solvent and both blocks, and therefore expands the range of accessible self-assembled morphologies. In particular, the distribution of solvent molecules plays a key role in determining the microstructure and its characteristic domain spacing. In this study, concentration dependent structures formed by poly(styrene-b-ethylene-alt-propylene) (PS-PEP) solution in squalane are investigated using small-angle X-ray scattering. This reveals that squalane is essentially completely segregated into the PEP domains. In addition, the conformation of the PS block changes from stretched to nearly fully relaxed (i.e., Gaussian conformation) as amounts of squalane increases. NRF

  9. Renewable Energy Essentials: Concentrating Solar Thermal Power

    Energy Technology Data Exchange (ETDEWEB)



    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.

  10. The concentration of health care expenditures, revisited. (United States)

    Berk, M L; Monheit, A C


    In two previous publications, we described the distribution of health care expenditures among the civilian, noninstitutionalized U.S. population, specifically in terms of the share of aggregate expenditures accounted for by the top spenders in the distribution. Our focus revealed considerably skewed distribution, with a relatively small proportion of the population accounting for a large share of expenditures. In this paper we update our previous tabulations (last computed using data more than a decade old) with new data from the 1996 Medical Expenditure Panel Survey (MEPS). Our findings show that the skewed concentration of health care expenditures has remained very stable; 5 percent of the population accounts for the majority of health expenditures.

  11. 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


    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.

  12. Modular off-axis solar concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Plesniak, Adam P; Hall, John C


    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. Aerobic growth at nanomolar oxygen concentrations

    DEFF Research Database (Denmark)

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


    known. These capabilities also provide a framework for reconstructing a critical period in the history of life, because low, but not negligible, atmospheric oxygen levels could have persisted before the "Great Oxidation" of the Earth's surface about 2.3 to 2.4 billion years ago. Here, we show......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...... that Escherichia coli K-12, chosen for its well-understood biochemistry, rapid growth rate, and low-oxygen-affinity terminal oxidase, grows at oxygen levels of ≤ 3 nM, two to three orders of magnitude lower than previously observed for aerobes. Our study expands both the environmental range and temporal history...

  14. Aerobic growth at nanomolar oxygen concentrations

    DEFF Research Database (Denmark)

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


    known. These capabilities also provide a framework for reconstructing a critical period in the history of life, because low, but not negligible, atmospheric oxygen levels could have persisted before the “Great Oxidation” of the Earth’s surface about 2.3 to 2.4 billion years ago. Here, we show......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...... that Escherichia coli K-12, chosen for its well-understood biochemistry, rapid growth rate, and low-oxygen-affinity terminal oxidase, grows at oxygen levels of ≤ 3 nM, two to three orders of magnitude lower than previously observed for aerobes. Our study expands both the environmental range and temporal history...

  15. Prediction Methods for Blood Glucose Concentration

    DEFF Research Database (Denmark)

    discussions which allowed to receive direct feedback from the point of view of different disciplines. This book is based on the contributions of that workshop and is intended to convey an overview of the different aspects involved in the prediction. The individual chapters are based on the presentations given...... EEG signals to predict upcoming hypoglycemic situations in real-time by employing artificial neural networks. The results of a 30-day long clinical study with the implanted device and the developed algorithm are presented. The chapter “Meta-Learning Based Blood Glucose Predictor for Diabetic...... 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...

  16. High estrogen concentrations in receiving river discharge from a concentrated livestock feedlot. (United States)

    Chen, Te-San; Chen, Ting-Chien; Yeh, Kuei-Jyum C; Chao, How-Ran; Liaw, Ean-Tun; Hsieh, Chi-Ying; Chen, Kuan-Chung; Hsieh, Lien-Te; Yeh, Yi-Lung


    Environmental estrogenic chemicals interrupt endocrine systems and generate reproductive abnormalities in wildlife, especially natural and synthetic estrogenic steroid hormones such as 17beta-estradiol (E2), estrone (E1), estriol (E3), 17alpha-ethynylestradiol (EE2), and diethylstilbestrol (DES). Concentrated animal feedlot operations (CAFOs) are of particular concern since large amounts of naturally excreted estrogens are discharged into aquatic environments. This study investigated E2, E1, E3, EE2, and DES with high performance liquid chromatography/tandem mass (HPLC-MS/MS) analyses along Wulo Creek in southern Taiwan, near a concentrated livestock feedlot containing 1,030,000 broiler chickens, 934,000 laying hens, 85,000 pigs, and 1500 cattle. Sampling was performed from December 2008 to May 2009, in which 54 samples were collected. Experimental results indicate that concentrations of EE2 were lower than the limit of detection (LOD), and concentrations of DES were only detected twice. Concentrations ranged from 7.4 to 1267 ng/L for E1, from not detected (ND) to 313.6 ng/L for E2, and from ND to 210 ng/L for E3. E1 had the highest average mass fraction (72.2 + or - 3.6%), which was significantly higher than E3 (16.2 + or - 1.7%) and E2 (11.5 + or - 2.6%). Additionally, the mean E2 equivalent quotient (EEQ) ranged from 17.3 to 137.9 ng-E2/L. Despite having a markedly lower concentration than E1, E2 more significantly contributed (52.4 + or - 6.0%) EEQ than E1 (19.7 + or - 3.5%). Moreover, the concentrations of E2, E1, and E3 upstream were significantly higher than concentrations downstream, suggesting a high attenuation effect and fast degradation in the study water. Most concentrations in winter season were higher than those of spring season due to the low dilution effect and low microbial activity in the winter season. Based on the results of this study, we recommend further treatment of the wastewater discharge from the feedlot.

  17. Toxicity Data to Determine Refrigerant Concentration Limits

    Energy Technology Data Exchange (ETDEWEB)

    Calm, James M.


    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.


    Energy Technology Data Exchange (ETDEWEB)

    P. Bernot


    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

  19. Diverse microbial species survive high ammonia concentrations (United States)

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


    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. Seismic Performance Evaluation of Concentrically Braced Frames (United States)

    Hsiao, Po-Chien

    Concentrically braced frames (CBFs) are broadly used as lateral-load resisting systems in buildings throughout the US. In high seismic regions, special concentrically braced frames (SCBFs) where ductility under seismic loading is necessary. Their large elastic stiffness and strength efficiently sustains the seismic demands during smaller, more frequent earthquakes. During large, infrequent earthquakes, SCBFs exhibit highly nonlinear behavior due to brace buckling and yielding and the inelastic behavior induced by secondary deformation of the framing system. These response modes reduce the system demands relative to an elastic system without supplemental damping. In design the re reduced demands are estimated using a response modification coefficient, commonly termed the R factor. The R factor values are important to the seismic performance of a building. Procedures put forth in FEMAP695 developed to R factors through a formalized procedure with the objective of consistent level of collapse potential for all building types. The primary objective of the research was to evaluate the seismic performance of SCBFs. To achieve this goal, an improved model including a proposed gusset plate connection model for SCBFs that permits accurate simulation of inelastic deformations of the brace, gusset plate connections, beams and columns and brace fracture was developed and validated using a large number of experiments. Response history analyses were conducted using the validated model. A series of different story-height SCBF buildings were designed and evaluated. The FEMAP695 method and an alternate procedure were applied to SCBFs and NCBFs. NCBFs are designed without ductile detailing. The evaluation using P695 method shows contrary results to the alternate evaluation procedure and the current knowledge in which short-story SCBF structures are more venerable than taller counterparts and NCBFs are more vulnerable than SCBFs.

  1. Microfluidic Paper-Based Sample Concentration Using Ion Concentration Polarization with Smartphone Detection

    Directory of Open Access Journals (Sweden)

    Xue Li


    Full Text Available A simple method for microfluidic paper-based sample concentration using ion concentration polarization (ICP with smartphone detection is developed. The concise and low-cost microfluidic paper-based ICP analytical device, which consists of a black backing layer, a nitrocellulose membrane, and two absorbent pads, is fabricated with the simple lamination method which is widely used for lateral flow strips. Sample concentration on the nitrocellulose membrane is monitored in real time by a smartphone whose camera is used to collect the fluorescence images from the ICP device. A custom image processing algorithm running on the smartphone is used to track the concentrated sample and obtain its fluorescence signal intensity for quantitative analysis. Two different methods for Nafion coating are evaluated and their performances are compared. The characteristics of the ICP analytical device especially with intentionally adjusted physical properties are fully evaluated to optimize its performance as well as to extend its potential applications. Experimental results show that significant concentration enhancement with fluorescence dye sample is obtained with the developed ICP device when a fast depletion of fluorescent dye is observed. The platform based on the simply laminated ICP device with smartphone detection is desired for point-of-care testing in settings with poor resources.

  2. Concentration of off-axis radiation by solar concentrators for space power (United States)

    Jefferies, Kent S.


    Four types of off-axis radiation are discussed. These are: (1) small off-axis angles during walk-off, (2) large off-axis angles, (3) an extended off-axis source such as Earth albedo, and (4) miscellaneous off-axis sources including radio frequency sources and local point sources. A code named OFFSET has been developed to represent the solar concentrator being developed for Space Station Freedom. It is a detailed, ray-tracing model which represents 50 ray originating points on the Sun and reflections from 10 points on each of the 456 concentrator facets. Results of this code are generally similar to the PIXEL results although there are small differences due to the more detailed representations of the Sun and concentrator that were used in the OFFSET code.

  3. 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)


    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)

  4. 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


    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...

  5. 21 CFR 169.178 - Concentrated vanilla flavoring. (United States)


    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Concentrated vanilla flavoring. 169.178 Section... Food Dressings and Flavorings § 169.178 Concentrated vanilla flavoring. (a) Concentrated vanilla... statement of ingredients prescribed for vanilla flavoring by § 169.177, except that it is concentrated...

  6. 21 CFR 169.176 - Concentrated vanilla extract. (United States)


    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Concentrated vanilla extract. 169.176 Section 169... Dressings and Flavorings § 169.176 Concentrated vanilla extract. (a) Concentrated vanilla extract conforms... ingredients prescribed for vanilla extract by § 169.175, except that it is concentrated to remove part of...

  7. 21 CFR 146.145 - Orange juice from concentrate. (United States)


    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Orange juice from concentrate. 146.145 Section 146... Juices and Beverages § 146.145 Orange juice from concentrate. (a) Orange juice from concentrate is the food prepared by mixing water with frozen concentrated orange juice as defined in § 146.146 or...

  8. Concentrated flow erosion processes under planned fire (United States)

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


    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

  9. Tracking-integrated systems for concentrating photovoltaics (United States)

    Apostoleris, Harry; Stefancich, Marco; Chiesa, Matteo


    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.

  10. Non-concentration of return times

    CERN Document Server

    Gurel-Gurevich, Ori


    We show that the distribution of the first return time tau to the origin, v, of a simple random walk on an infinite recurrent graph is heavy tailed and non-concentrated. More precisely, if d_v is the degree of v then for any t>1 we have P_v(tau \\ge t) > c d_v^{-1} t^{-1/2} and P_v(tau = t | tau \\ge t) < C log(d_v t) t^{-1}. The first bound is attained for all t when the underlying graph is Z, and as for the second bound, we construct an example of a recurrent graph G for which it is attained for infinitely many t's. Furthermore, we show that in the comb product of G with Z, two independent random walks collide infinitely many times almost surely. This answers negatively a question of Krishnapur and Peres who asked whether any comb product of two infinite recurrent graphs has the finite collision property.

  11. Blood glucose concentration in pediatric outpatient surgery. (United States)

    Somboonviboon, W; Kijmahatrakul, W


    Blood glucose concentration was measured in 84 pediatric patients who were scheduled for outpatient surgery at Chulalongkorn Hospital. They were allocated into 3 groups according to their ages, group 1:less than 1 year of age, group 2:1 to 5 years of age and group 3:over 5 years. The fasting times were approximately 8-12 hours. All patients received standard general anesthesia under mask. No glucose solution was given during operation. Preoperative mean blood glucose were 91.09 +/- 17.34, 89.55 +/- 18.69 and 82.14 +/- 16.14 mg/dl in group 1, 2 and 3 while the postoperative mean glucose values were 129.07 +/- 37.90, 115.62 +/- 29.63 and 111.53 +/- 23.07 mg/dl respectively. The difference between pre- and post-operative values were statistically significant difference (P postoperative glucose values may be due to stress response from surgery and anesthesia. We would suggest that the parents give the fluid to their children according to our instructions in order to prevent dehydration and hypoglycemia especially in small infants.

  12. Peanut cake concentrations in massai grass silage

    Directory of Open Access Journals (Sweden)

    Luciano S. Lima


    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.

  13. Luminescent Solar Concentrators in the Algal Industry (United States)

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


    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.

  14. 10-kilowatt photovoltaic concentrator array fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, J.A.; Donovan, R.L.; Broadbent, S.


    The PCA is based on the use of an acrylic Fresnel lens to concentrate sunlight on high intensity solar cells. The array with modified heat sinks was fabricated to determine the impact on electrical performance due to lower weight heat sinks and reduced thermal dissipation surfaces. The array with modified heat sinks was fabricated to determine the impact on electrical performance due to lower weight heat sinks and reduced thermal dissipation surfaces. The array fabrication proceeded with normal problems expected of preproduction prototypes. Three major problems occurred in the areas of the dimensional adequacy of the environmental housing for the Photovoltaic Modules, the cell/substrate assembly and the azimuth drive structural integrity. The cost optimization study identified a new lower weight heat sink design that would reduce the heat sink weight by 50% and the array cost by approximately 3.1% for a loss of only 7% in annularized electrical power generation. The production cost estimate provides an indicator that an overall 87% learning curve can be achieved and the cost of the 5000th unit could be $5.30 per watt in 1979 dollars. System level costs were also developed to project a busbar energy cost for a 10 MW system produced at the 500th unit. This system would provide energy at 24 cents per kilowatt hour average over a 30 year projected life. As a result of wind tunnel tests and the fabrication experience, an array has been designed for production. The key elements of the redesign are discussed. (MHR)

  15. Halo mass - concentration relation from weak lensing

    CERN Document Server

    Mandelbaum, Rachel; Hirata, Christopher M


    We perform a statistical weak lensing analysis of dark matter profiles around tracers of halo mass from galactic- to cluster-size halos. In this analysis we use 170,640 isolated ~L* galaxies split into ellipticals and spirals, 38,236 groups traced by isolated spectroscopic Luminous Red Galaxies (LRGs) and 13,823 MaxBCG clusters from the Sloan Digital Sky Survey (SDSS) covering a wide range of richness. Together these three samples allow a determination of the density profiles of dark matter halos over three orders of magnitude in mass, from 10^{12} M_{sun} to 10^{15} M_{sun}. The resulting lensing signal is consistent with an NFW or Einasto profile on scales outside the central region. We find that the NFW concentration parameter c_{200b} decreases with halo mass, from around 10 for galactic halos to 4 for cluster halos. Assuming its dependence on halo mass in the form of c_{200b} = c_0 [M/(10^{14}M_{sun}/h)]^{\\beta}, we find c_0=4.6 +/- 0.7 (at z=0.22) and \\beta=0.13 +/- 0.07, with very similar results for t...

  16. Arterial Stiffness and Dialysis Calcium Concentration

    Directory of Open Access Journals (Sweden)

    Fabrice Mac-Way


    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.

  17. Elevated hair cortisol concentrations in endurance athletes. (United States)

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


    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 (pathletes 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.

  18. Optimum Concentration Ratio Analysis Using Dynamic Thermal Model for Concentrated Photovoltaic System (United States)


    hplate = Hsil/tau_H ; Pc = hplate*(A)*(T-Tstream) ;% convective cooling of the cell by the ambient air % as it stands now, Pc remains constant...Iberoamericano de Estudiantes de Ingenieria Electrica, s.l. : Cibelec, 2005. 40. Brogren, Maria. Optical Effeciency of Low-Concentrating Solar Energy

  19. Sterile Filtration of Highly Concentrated Protein Formulations: Impact of Protein Concentration, Formulation Composition, and Filter Material. (United States)

    Allmendinger, Andrea; Mueller, Robert; Huwyler, Joerg; Mahler, Hanns-Christian; Fischer, Stefan


    Differences in filtration behavior of concentrated protein formulations were observed during aseptic drug product manufacturing of biologics dependent on formulation composition. The present study investigates filtration forces of monoclonal antibody formulations in a small-scale set-up using polyvinylidene difluoride (PVDF) or polyethersulfone (PES) filters. Different factors like formulation composition and protein concentration related to differences in viscosity, as well as different filtration rates were evaluated. The present study showed that filtration behavior was influenced by the presence or absence of a surfactant in the formulation, which defines the interaction between filter membrane and surface active formulation components. This can lead to a change in filter resistance (PES filter) independent on the buffer system used. Filtration behavior was additionally defined by rheological non-Newtonian flow behavior. The data showed that high shear rates resulting from small pore sizes and filtration pressure up to 1.0 bar led to shear-thinning behavior for highly concentrated protein formulations. Differences in non-Newtonian behavior were attributed to ionic strength related to differences in repulsive and attractive interactions. The present study showed that the interplay of formulation composition, filter material, and filtration rate can explain differences in filtration behavior/filtration flux observed for highly concentrated protein formulations thus guiding filter selection.

  20. Concentration and flux of bioaerosol and environmental factors

    Institute of Scientific and Technical Information of China (English)


    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.

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


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


    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...

  2. Rotary Apparatus Concentrates And Separates Micro-Organisms (United States)

    Noever, David A.


    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.

  3. Platelet concentration in platelet concentrates and periodontal regeneration-unscrambling the ambiguity (United States)

    Suchetha, A.; Lakshmi, P.; Bhat, Divya; Mundinamane, Darshan B.; Soorya, K. V.; Bharwani, G. Ashit


    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. PMID:26681857

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

    Directory of Open Access Journals (Sweden)

    A Suchetha


    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.

  5. Utility of cerebrospinal fluid drug concentration as a surrogate for unbound brain concentration in nonhuman primates. (United States)

    Nagaya, Yoko; Nozaki, Yoshitane; Kobayashi, Kazumasa; Takenaka, Osamu; Nakatani, Yosuke; Kusano, Kazutomi; Yoshimura, Tsutomu; Kusuhara, Hiroyuki


    In central nervous system drug discovery, cerebrospinal fluid (CSF) drug concentration (C(CSF)) has been widely used as a surrogate for unbound brain concentrations (C(u,brain)). However, previous rodent studies demonstrated that when drugs undergo active efflux by transporters, such as P-glycoprotein (P-gp), at the blood-brain barrier, the C(CSF) overestimates the corresponding C(u,brain). To investigate the utility of C(CSF) as a surrogate for interstitial fluid (ISF) concentration (C(ISF)) in nonhuman primates, this study simultaneously determined the C(CSF) and C(ISF) of 12 compounds, including P-gp substrates, under steady-state conditions in cynomolgus monkeys using intracerebral microdialysis coupled with cisternal CSF sampling. Unbound plasma concentrations of non- or weak P-gp substrates were within 2.2-fold of the C(ISF) or C(CSF), whereas typical P-gp substrates (risperidone, verapamil, desloratadine, and quinidine) showed ISF-to-plasma unbound (K(p,uu,ISF)) and CSF-to-plasma unbound concentration ratios (K(p,uu,CSF)) that were appreciably lower than unity. Although the K(p,uu,CSF) of quinidine, verapamil, and desloratadine showed a trend of overestimating the K(p,uu,ISF), K(p,uu,CSF) showed a good agreement with K(p,uu,ISF) within 3-fold variations for all compounds examined. C(u,brain) of some basic compounds, as determined using brain homogenates, overestimated the C(ISF) and C(CSF). Therefore, C(CSF) could be used as a surrogate for C(ISF) in nonhuman primates.

  6. Prevalence, concentration, spoilage, and mitigation of Alicyclobacillus spp. in tropical and subtropical fruit juice concentrates. (United States)

    Danyluk, Michelle D; Friedrich, Loretta M; Jouquand, Celine; Goodrich-Schneider, Renee; Parish, Mickey E; Rouseff, Russell


    The presence of Alicyclobacillus in fruit juices and concentrates poses a serious problem for the juice industry. This study was undertaken to determine the (i) prevalence, concentration, and species of Alicyclobacillus in tropical and subtropical concentrates; (ii) efficacy of aqueous chlorine dioxide in reducing Alicyclobacillus spp. spores on tropical and subtropical fruit surfaces; and (iii) fate of and off-flavor production by Alicyclobacillus acidoterrestris in mango and pineapple juices. One hundred and eighty tropical and subtropical juice concentrates were screened for the presence and concentration of Alicyclobacillus spp. If found, the species of Alicyclobacillus was determined by 16S rDNA sequencing and analysis with NCI BLAST. Of these samples, 6.1% were positive for Alicyclobacillus, and nine A. acidoterrestris strains and two Alicyclobacillus acidocaldarius strains were identified. A five-strain cocktail of Alicyclobacillus spp. was inoculated onto the surface of fruits (grapefruit, guava, limes, mangoes, oranges and pineapple), which were then washed with 0, 50, or 100 ppm aqueous chlorine dioxide. Significant reductions due to chlorine dioxide were only seen on citrus fruits. A five-strain cocktail of A. acidoterrestris was inoculated into mango and pineapple juices. Microbial populations were enumerated over a 16-day period. Aroma compounds in the juice were analyzed by GC-olfactometry (GC-O) and confirmed using GC-MS. GC-O of mango juice identified previously reported medicinal/antiseptic compounds. GC-O of pineapple juice revealed an unexpected "cheese" off-aroma associated with 2-methylbutyric acid and 3-methylbutyric acid.

  7. Plasma renin activities, angiotensin II concentrations, atrial natriuretic peptide concentrations and cardiopulmonary function values in dogs with severe heartworm disease. (United States)

    Kitagawa, H; Kitoh, K; Inoue, H; Ohba, Y; Suzuki, F; Sasaki, Y


    Relationships among plasma renin activities (PRA), plasma angiotensin II (ATII) concentrations, atrial natriuretic peptide (ANP) concentrations and cardiopulmonary function values were examined in dogs with ascitic pulmonary heartworm disease and acute- and chronic-vena caval syndrome (CS). PRA, plasma ATII concentration and plasma ANP concentration tended to be higher or were significantly higher in dogs with ascites, acute- and chronic-CS. PRA correlated significantly with plasma ATII concentration, WBC count, ALP activity, plasma concentrations of urea nitrogen, creatinine, sodium, potassium, and chloride, right ventricular endodiastolic pressure and right atrial pressure. Plasma ATII concentration correlated significantly with WBC count, plasma concentrations of urea nitrogen, sodium, and potassium, right ventricular endodiastolic pressure and right atrial pressure. Plasma ANP concentration did not correlate with PRA or ATII concentration, but correlated significantly only with pulmonary arterial pressure.

  8. 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


    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.


    Energy Technology Data Exchange (ETDEWEB)

    Zamecnik, J; Alex Cozzi, A


    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{reg_sign} 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.

  10. Concentrating Solar Power Gen3 Demonstration Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    Mehos, Mark [National Renewable Energy Lab. (NREL), Golden, CO (United States); Turchi, Craig [National Renewable Energy Lab. (NREL), Golden, CO (United States); Vidal, Judith [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wagner, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ma, Zhiwen [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ho, Clifford [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kolb, William [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Andraka, Charles [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kruizenga, Alan [Sandia National Lab. (SNL-CA), Livermore, CA (United States)


    Today's power-tower concentrating solar power (CSP) technology exists in large part as a result of Department of Energy (DOE) and utility industry funding of demonstration systems in the 1980s and 1990s. Today's most advanced towers are integrated with molten-salt thermal energy storage, delivering thermal energy at 565 degrees C for integration with conventional steam-Rankine cycles. The supercritical carbon dioxide power cycle has been identified as a likely successor to the steam-Rankine power cycle due to its potential for high efficiency when operating at elevated temperatures of 700 degrees C or greater. Over the course of the SunShot Initiative, DOE has supported a number of technology pathways that can operate efficiently at these temperatures and that hold promise to be reliable and cost effective. Three pathways - molten salt, particle, and gaseous - were selected for further investigation based on a two-day workshop held in August of 2016. The information contained in this roadmap identifies research and development challenges and lays out recommended research activities for each of the three pathways. DOE foresees that by successfully addressing the challenges identified in this roadmap, one or more technology pathways will be positioned for demonstration and subsequent commercialization within the next ten years. Based on current knowledge of the three power tower technologies, all three have the potential to achieve the SunShot goal of 6 cents/kilowatt-hour. Further development, modeling, and testing are now required to bring one or more of the technologies to a stage where integrated system tests and pilot demonstrations are feasible.

  11. Cadmium and Chrome Concentrations in Human Milk

    Directory of Open Access Journals (Sweden)

    Sima Nazarpour


    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.

  12. V-trough concentrator for low concentration photovoltaic systems; Cavidades tipo V para sistemas fotovoltaicos de baja concentracion

    Energy Technology Data Exchange (ETDEWEB)

    Alonso Abella, M.; Chenlo, F.; Valera, P.; Enrile, J.; Osmar, R.


    A 1.2 MWp photovoltaic (PV) plant, with double concentration and two axis solar tracking, will be installed in Seville. It is based on V-trough concentration with the objective of reduced energy generation cost. Low concentration (?2X) is required because of efficiency and reliability of standard manufactured PV modules. This work analyses the geometry and optical efficiency of the V-trough concentrator, and the electrical behavior of standard PV cells and modules operating at low level concentration. (Author)

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

    DEFF Research Database (Denmark)

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


    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 responses...... the cows preferred a mixture containing Barley and Oats. Also Wheat based concentrate appeared to be preferred to concentrate based on Maize or Barley and the cows did not like the Fat rich or the pure Artificially dried grass concentrate used in the experiment....

  14. 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


    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.

  15. Barium concentration in grain of Aegilops and Triticum species

    Directory of Open Access Journals (Sweden)

    Denčić Srbislav S.


    Full Text Available The aim of this study was to evaluate the concentration of barium in grain of various Aegilops and Triticum species with different genomes. The studied species differed significantly with respect to the concentration of barium. The grain of wild diploid Aegilops speltoides, the donor of B genome, contained significantly higher Ba concentration than all other analyzed genotypes. Wild and cultivated tetraploid wheats (Triticum diciccoides, Triticum dicoccon, Triticum turgidum and Triticum durum had the lowest Ba concentration in grain. The modern cultivated hexaploid varieties presented substantial variation in grain concentration of barium. The highest Ba concentration (3.42 mg/kg occurred in Serbian winter wheat variety Panonnia.

  16. Concentration phenomena in the semilinear parabolic equation

    Institute of Scientific and Technical Information of China (English)

    TAN; Zhong


    [1]Fujita, H., On the blowing up of solutions of the Chauch problem for u=Δu+u1+α, J. Fac. Sci. Univ. Tokyo Sect. I, 966, 3: 09.[2]Ni, W. -M., Sacks, P. E., Tavantzis, J., On the asymptotic behavior of solutions of certain quasilinear equations of parabolic type, J. Differential Equations, 984, 54: 97.[3]Cazenave, T., Lions, P. L., Solutions globales d'equations de la chaleur semilineaires, Comm. in Partial Differential Equations, 984, 9(0): 955.[4]Giga, Y., A bound for global solutions of semilinear heat equations, Commun. Math. Phys., 986, 03: 45.[5]Galaktionov, V., Vazquez, J. L., Continuation of blow-up solutions of nonlinear heat equations in several space dimensions, Comm. Pure Appl. Math., 997, 50: .[6]Rey, O., The role of the Green's function in a nonlinear elliptic equation involving the critical Sobolev exponent, J. Func. Anal., 990, 89: .[7]Wei Juncheng, Asymptotic behavior of least energy solution to a semilinear Dirichlet problem near the critical exponent, J. Math. Soc. Japan, 998, 50(): 39.[8]Lions, P. L., The concentration-compactness principle in the calculus of variations, The limit case ,2, Rev. Mat. Iberoamerioana, 985, : 45, 45.[9]Brezis, H., Elliptic equations with limiting Sobolev exponents——the impact of topology, Commun. Pure and Appl. Math., 986, XXXXIX: S7.[10]Sacks, J., Uhlenbeck, K., The existence of minimal immersions of 2-spheres, Ann. Math., 98, 3: .[11]Zhu Xiping, Nontrivial solutions of quasilinear elliptic equation involving critical growth, Science in China (in Chinese), Ser. A, 988, (3): 225.[12]Pohozaev, S. I., Eigenfunctions of the equation -Δu+λf(u)=0, Soviet. Math. Dold., 965, 6: 408.[13]Gidas, B., Ni, W. -M., Nirenberg, L., Symmetry and related properties via the maximum principle, Comm. Math. Phys., 979, 68: 209.[14]Ni, W. -M., Sacks, P. E., Singular behaviour in nonlinear parabolic equations, Tran. of the AMS, 985, 287(2): 657.[15]Ni, W. -M., Sacks, P. E

  17. Effects of high nitrogen concentrations on the growth of submersed macrophytes at moderate phosphorus concentrations. (United States)

    Yu, Qing; Wang, Hong-Zhu; Li, Yan; Shao, Jian-Chun; Liang, Xiao-Min; Jeppesen, Erik; Wang, Hai-Jun


    Eutrophication of lakes leading to loss of submersed macrophytes and higher turbidity is a worldwide phenomenon, attributed to excessive loading of phosphorus (P). However, recently, the role of nitrogen (N) for macrophyte recession has received increasing attention. Due to the close relationship between N and P loading, disentanglement of the specific effects of these two nutrients is often difficult, and some controversy still exists as to the effects of N. We studied the effects of N on submersed macrophytes represented by Vallisneria natans (Lour.) Hara in pots positioned at three depths (0.4 m, 0.8 m, and 1.2 m to form a gradient of underwater light conditions) in 10 large ponds having moderate concentrations of P (TP 0.03 ± 0.04 mg L(-1)) and five targeted concentrations of total nitrogen (TN) (0.5, 2, 10, 20, and 100 mg L(-1)), there were two ponds for each treatment. To study the potential shading effects of other primary producers, we also measured the biomass of phytoplankton (ChlaPhyt) and periphyton (ChlaPeri) expressed as chlorophyll a. We found that leaf length, leaf mass, and root length of macrophytes declined with increasing concentrations of TN and ammonium, while shoot number and root mass did not. All the measured growth indices of macrophytes declined significantly with ChlaPhyt, while none were significantly related to ChlaPeri. Neither ChlaPhyt nor ChlaPeri were, however, significantly negatively related to the various N concentrations. Our results indicate that shading by phytoplankton unrelated to the variation in N loading and perhaps toxic stress exerted by high nitrogen were responsible for the decline in macrophyte growth.


    Institute of Scientific and Technical Information of China (English)

    Fengqi Yan; Huanling Hu; Tong Yu


    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.

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

    Directory of Open Access Journals (Sweden)

    Jin-Hui Luo


    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.

  20. 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


    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...

  1. [Changes in platelet concentrates from dogs due to storage. II. Biochemical changes in concentrate plasma]. (United States)

    Klein, A; Adamik, A; Mischke, R


    Platelet concentrate (PC) obtained from dogs with an automatic cell separator was stored in C4-cell separation sets with low gasdiffusionable Polyvinylchlorid (PVC) storage containers or in C4L-sets developed for storage with high gasdiffusionable Polyolefin(PO) containers, respectively. PC were stored for 10 days under permanent agitation at 22 degrees C (C4/22 degrees C, n = 10; C4L/22 degrees C, n = 11) or at 4 degrees C (C4L/4 degrees C, n = 6), respectively. Measurements were carried out directly after production of the PC, after 6 hours and then daily during the 10-day storage period. In the second part of this paper the results of pH, the concentration of bicarbonate, glucose, lactate and potassium ions as well as the activity of lactate dehydrogenase (LDH) are presented. The varying duration and intensity of the energy metabolism of the platelets and different part of glycolysis became obvious by the consumption of glucose and production of lactate, which differed significantly between the different storage conditions. Resulting from this, the mean pH decreased under the limit prescribed for human PC (pH = 6.3) already after a storage period of 3 days due to the slight capacity of gas diffusion in PVC-containers (C4/22 degrees C). In the PO-containers the pH fell below this limit at 22 degrees C (C4L/22 degrees C) after a storage period of 5 days and at 4 degrees C (C4L/4 degrees C) after 10 days. The latter reflects the high gas diffusion capacity of the PO-containers and the decreased metabolism activity at 4 degrees C. The increase of activity of LDH and of the concentration of potassium ions, which are localized in the cytosol of platelets, depended also on the different storage conditions and, thereby, reflected the different rapidity of increasing membrane permeability or the destruction of the cell membrane, respectively. The results of this study nearly are in agreement with the changes of platelet function shown in part I. Biochemical changes occur

  2. Field methods for measuring concentrated flow erosion (United States)

    Castillo, C.; Pérez, R.; James, M. R.; Quinton, J. N.; Taguas, E. V.; Gómez, J. A.


    techniques (3D) for measuring erosion from concentrated flow (pole, laser profilemeter, photo-reconstruction and terrestrial LiDAR) The comparison between two- and three-dimensional methods has showed the superiority of the 3D techniques for obtaining accurate cross sectional data. The results from commonly-used 2D methods can be subject to systematic errors in areal cross section that exceed magnitudes of 10 % on average. In particular, the pole simplified method has showed a clear tendency to understimate areas. Laser profilemeter results show that further research on calibrating optical devices for a variety of soil conditions must be carried out to improve its performance. For volume estimations, photo-reconstruction results provided an excellent approximation to terrestrial laser data and demonstrate that this new remote sensing technique has a promising application field in soil erosion studies. 2D approaches involved important errors even over short measurement distances. However, as well as accuracy, the cost and time requirements of a technique must be considered.

  3. Salivary Glucose Concentration and Excretion in Normal and Diabetic Subjects

    Directory of Open Access Journals (Sweden)

    Cedric Jurysta


    saliva glucose concentration was comparable, however, to that of blood glucose concentration. The relationship between these two variables was also documented in normal subjects and diabetic patients undergoing an oral glucose tolerance test.


    NARCIS (Netherlands)



    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

  5. 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


    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.


    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...

  7. Absolute Quantification of Individual Biomass Concentrations in a Methanogenic Coculture

    NARCIS (Netherlands)

    Junicke, H.; Abbas, B.; Oentoro, J.; Van Loosdrecht, M.; Kleerebezem, R.


    Identification of individual biomass concentrations is a crucial step towards an improved understanding of anaerobic digestion processes and mixed microbial conversions in general. The knowledge of individual biomass concentrations allows for the calculation of biomass specific conversion rates whic

  8. Use of a Concentration Game for Environmental Chemistry Class Review (United States)

    Nowosielski, Danica A.


    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.

  9. Luminescent Solar Concentrators – a low cost photovoltaics alternative

    NARCIS (Netherlands)

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


    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

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

    Energy Technology Data Exchange (ETDEWEB)


    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.

  11. 21 CFR 146.150 - Canned concentrated orange juice. (United States)


    ... of orange juice soluble solids in degrees Brix; for example, a 62° Brix concentrate in 1-gallon cans may be named on the label “canned concentrated orange juice, 62° Brix”. If the food does not...

  12. Measures of Buyer Concentration in the Australian Wool Market



    The study uses empirical measures of market concentration to examine buyer competition in wool between 1974 and 1992. Three measures of concentration are examined, concentration ratios, Herfindahl indices and Lorenz curves. Data from the Australian Council of Wool Exporters are used to obtain estimates of these measures over the sample period. The results indicate that the buying sector in the Australian wool market is relatively concentrated and calculation of Spearman correlation coefficien...

  13. Novel materials and devices for sunlight concentrating systems (United States)

    Hovel, H. J.


    An economic analysis of photovoltaic conversion under concentrated sunlight has been performed which demonstrates that solar cell efficiency, concentrator efficiency, and concentrator cost are the most important parameters in a concentrating photovoltaic system; solar cell cost is only of secondary importance. Six novel structures are described, including modified conventional Si cells Ga(1-x)Al(x)As/GaAs, interdigitated cells, vertical and horizontal multijunction cells and 'multicolor' devices.

  14. Maternal exposure to metals—Concentrations and predictors of exposure

    Energy Technology Data Exchange (ETDEWEB)

    Callan, A.C., E-mail: [Centre for Ecosystem Management, Edith Cowan University, 270 Joondalup Drive, Joondalup, WA 6027 (Australia); Hinwood, A.L.; Ramalingam, M.; Boyce, M. [Centre for Ecosystem Management, Edith Cowan University, 270 Joondalup Drive, Joondalup, WA 6027 (Australia); Heyworth, J. [School Population Health, The University of Western Australia, 35 Stirling Highway Crawley, WA 6009 (Australia); McCafferty, P. [ChemCentre, PO Box 1250, Bentley, WA 6983 (Australia); Odland, J.Ø. [Department of Community Medicine, University of Tromsø, N-9037 Tromsø (Norway)


    A variety of metals are important for biological function but have also been shown to impact health at elevated concentrations, whereas others have no known biological function. Pregnant women are a vulnerable population and measures to reduce exposure in this group are important. We undertook a study of maternal exposure to the metals, aluminium, arsenic, copper, cobalt, chromium, lithium, manganese, nickel, selenium, tin, uranium and zinc in 173 participants across Western Australia. Each participant provided a whole blood and urine sample, as well as drinking water, residential soil and dust samples and completed a questionnaire. In general the concentrations of metals in all samples were low with the notable exception of uranium (blood U mean 0.07 µg/L, range <0.01–0.25 µg/L; urinary U mean 0.018 µg/g creatinine, range <0.01–0.199 µg/g creatinine). Factors that influenced biological concentrations were consumption of fish which increased urinary arsenic concentrations, hobbies (including mechanics and welding) which increased blood manganese concentrations and iron/folic acid supplement use which was associated with decreased concentrations of aluminium and nickel in urine and manganese in blood. Environmental concentrations of aluminium, copper and lithium were found to influence biological concentrations, but this was not the case for other environmental metals concentrations. Further work is underway to explore the influence of diet on biological metals concentrations in more detail. The high concentrations of uranium require further investigation. -- Highlights: • High concentrations of uranium with respect to international literature. • Environmental concentrations of Al, Cu and Li influenced urinary concentrations. • Exposure to mechanics/welding hobbies increased blood Mn concentrations. • Iron/Folic acid supplements reduced biological concentrations of Al, Ni and Mn.

  15. Recent developments in refractive concentrators for space photovoltaic power systems (United States)

    Piszczor, Michael F.; Oneill, Mark J.


    Since SPRAT 11, significant progress has been made in the development of refractive concentrator elements and components designed specifically for space applications. The status of the mini-dome Fresnel lens concentrator array is discussed and then the results of work recently completed in the area of prismatic cell covers for concentrator systems are summarized. This is followed by a brief discussion of some work just starting in the area of line-focus refractive concentrators for space.

  16. Serum sialic acid and CEA concentrations in human breast cancer.


    Hogan-Ryan, A.; Fennelly, J J; Jones, M.; Cantwell, B; Duffy, M J


    The concentration of bound sialic acid in the sera of 56 normal subjects and 65 subjects with breast cancer was measured, in order to determine (1) whether serum sialic acid concentrations are raised in breast cancer and (2) whether the concentration of sialic acid in serum reflects tumour stage. The amount of sialic acid in serum was compared to serum carcinoembryonic antigen (CEA) values. Urinary hydroxyproline and serum alkaline phosphatase concentrations were used as indicators of bone an...

  17. Evaluation of ceruloplasmin concentration in prognosis of human cancer.

    Directory of Open Access Journals (Sweden)

    Chakravarty,Prabir Kishore


    Full Text Available The serum ceruloplasmin concentration was determined in cancer patients before and after radiotherapy, and after relapse of cancer, The ceruloplasmin concentration in patients who responded to therapy, decreased to the range of normal controls. In patients who did not respond to treatment, the ceruloplasmin concentration was more or less elevated. In patients with relapse of cancer, the ceruloplasmin concentration was higher than before treatment.

  18. Partial reflection. [electron concentration of the D region (United States)


    Differential-absorption electron concentration and drifts wind data were collected on a daily basis along with daily winds data. The daily winds data are compared with the daily electron concentration data on the meridional prevailing wind are compared with the electron concentration. Results are briefly discussed.

  19. Classroom Carbon Dioxide Concentration, School Attendance, and Educational Attainment (United States)

    Gaihre, Santosh; Semple, Sean; Miller, Janice; Fielding, Shona; Turner, Steve


    Background: We tested the hypothesis that classroom carbon dioxide (CO[subscript 2]) concentration is inversely related to child school attendance and educational attainment. Methods: Concentrations of CO[subscript 2] were measured over a 3-5?day period in 60 naturally ventilated classrooms of primary school children in Scotland. Concentrations of…

  20. 21 CFR 146.153 - Concentrated orange juice for manufacturing. (United States)


    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Concentrated orange juice for manufacturing. 146... Canned Fruit Juices and Beverages § 146.153 Concentrated orange juice for manufacturing. (a) Concentrated orange juice for manufacturing is the food that complies with the requirements of composition and...

  1. 21 CFR 184.1979c - Whey protein concentrate. (United States)


    ... derived from milk that has been pasteurized, or the whey protein concentrate shall be subjected to... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Whey protein concentrate. 184.1979c Section 184... Listing of Specific Substances Affirmed as GRAS § 184.1979c Whey protein concentrate. (a) Whey...

  2. Progress in phosphors and filters for luminescent solar concentrators

    NARCIS (Netherlands)

    De Boer, D.K.G.; Broer, D.J.; Debije, M.G.; Keur, W.C.; Meijerink, A.; Ronda, C.R.; Verbunt, P.P.C.


    Luminescent solar concentrators would allow for high concentration if losses by reabsorption and escape could be minimized. We introducea phosphor with close-to-optimal luminescent properties and hardlyany reabsorption. A problem for use in a luminescent concentrator isthe large scattering of this m

  3. 21 CFR 146.146 - Frozen concentrated orange juice. (United States)


    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Frozen concentrated orange juice. 146.146 Section 146.146 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... the food concentrated to a dilution ratio of 3 plus 1 is “frozen concentrated orange juice” or...

  4. Determination of Parameters of PV Concentrating System With Heliostat (United States)

    Vardanyan, R.; Norsoyan, A.; Dallakyan, V.


    The structure of PV concentrating system with heliostat is analyzed. The mathematical model of system consisting of PV concentrating module and heliostat is developed. With the use of developed mathematical model the optimal parameters of the system are determined. The results of this work can be used during the design of PV concentrating systems with heliostats.

  5. 27 CFR 25.296 - Record of beer concentrate. (United States)


    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Record of beer concentrate..., DEPARTMENT OF THE TREASURY LIQUORS BEER Records and Reports § 25.296 Record of beer concentrate. (a) Daily records. A brewer who produces concentrate or reconstitutes beer shall maintain daily records...

  6. Nitrate concentrations in soil solutions below Danish forests

    DEFF Research Database (Denmark)

    Callesen, Ingeborg; Raulund-Rasmussen, Karsten; Gundersen, Per;


    had higher concentrations than forest-type 'other woodland'), (3) soil-type (humus soils showed above average concentrations, and fine textured soils had higher concentrations than coarse textured soils), and (4) sampling time. Unlike other investigations, there was no significant effect of tree...

  7. BH4 treatment in BH4-responsive PKU patients: preliminary data on blood prolactin concentrations suggest increased cerebral dopamine concentrations. (United States)

    van Vliet, Danique; Anjema, Karen; Jahja, Rianne; de Groot, Martijn J; Liemburg, Geertje B; Heiner-Fokkema, M Rebecca; van der Zee, Eddy A; Derks, Terry G J; Kema, Ido P; van Spronsen, Francjan J


    In phenylketonuria (PKU), cerebral neurotransmitter deficiencies have been suggested to contribute to brain dysfunction. Present treatment aims to reduce blood phenylalanine concentrations by a phenylalanine-restricted diet, while in some patients blood phenylalanine concentrations also respond to cofactor treatment with tetrahydrobiopterin (BH4). Recently, a repurposing approach of BH4 was suggested to increase cerebral neurotransmitter synthesis. To investigate whether BH4 may improve cerebral dopamine concentrations in PKU patients beyond its effect through lowering blood phenylalanine concentrations, we investigated blood prolactin concentrations-as a parameter of brain dopamine availability. We retrospectively compared blood prolactin in relation to blood phenylalanine concentrations of nine (male) BH4-responsive PKU patients, when being treated without and with BH4. Blood prolactin concentrations positively correlated to blood phenylalanine concentrations (p=0.002), being significantly lower with than without BH4 treatment (p=0.047). In addition, even in this small number of male patients, blood prolactin concentrations tended to be lower at increasing BH4 dose (p=0.054), while taking blood phenylalanine concentrations into account (p=0.002). In individual BH4-responsive patients, median blood prolactin concentrations were significantly lower while using BH4 than before using BH4 treatment (p=0.024), whereas median blood phenylalanine concentrations tended to be lower, but this did not reach statistical significance (p=0.107). Therefore, these data show that high blood phenylalanine in BH4-responsive PKU male patients seems to be associated with increased blood prolactin concentrations, suggesting reduced cerebral dopamine availability. Moreover, these data suggest that BH4 treatment in itself could decrease blood prolactin concentrations in a dose-responsive way, independent of blood phenylalanine concentrations. We conclude that these preliminary data


    Energy Technology Data Exchange (ETDEWEB)



    Thermal energy storage (TES) is an integral part of a concentrated solar power (CSP) system. It enables plant operators to generate electricity beyond on sun hours and supply power to the grid to meet peak demand. Current CSP sensible heat storage systems employ molten salts as both the heat transfer fluid and the heat storage media. These systems have an upper operating temperature limit of around 400 C. Future TES systems are expected to operate at temperatures between 600 C to 1000 C for higher thermal efficiencies which should result in lower electricity cost. To meet future operating temperature and electricity cost requirements, a TES concept utilizing thermochemical cycles (TCs) based on multivalent solid oxides was proposed. The system employs a pair of reduction and oxidation (REDOX) reactions to store and release heat. In the storage step, hot air from the solar receiver is used to reduce the oxidation state of an oxide cation, e.g. Fe3+ to Fe2+. Heat energy is thus stored as chemical bonds and the oxide is charged. To discharge the stored energy, the reduced oxide is re-oxidized in air and heat is released. Air is used as both the heat transfer fluid and reactant and no storage of fluid is needed. This project investigated the engineering and economic feasibility of this proposed TES concept. The DOE storage cost and LCOE targets are $15/kWh and $0.09/kWh respectively. Sixteen pure oxide cycles were identified through thermodynamic calculations and literature information. Data showed the kinetics of re-oxidation of the various oxides to be a key barrier to implementing the proposed concept. A down selection was carried out based on operating temperature, materials costs and preliminary laboratory measurements. Cobalt oxide, manganese oxide and barium oxide were selected for developmental studies to improve their REDOX reaction kinetics. A novel approach utilizing mixed oxides to improve the REDOX kinetics of the selected oxides was proposed. It partially


    Energy Technology Data Exchange (ETDEWEB)



    Thermal energy storage (TES) is an integral part of a concentrated solar power (CSP) system. It enables plant operators to generate electricity beyond on sun hours and supply power to the grid to meet peak demand. Current CSP sensible heat storage systems employ molten salts as both the heat transfer fluid and the heat storage media. These systems have an upper operating temperature limit of around 400 C. Future TES systems are expected to operate at temperatures between 600 C to 1000 C for higher thermal efficiencies which should result in lower electricity cost. To meet future operating temperature and electricity cost requirements, a TES concept utilizing thermochemical cycles (TCs) based on multivalent solid oxides was proposed. The system employs a pair of reduction and oxidation (REDOX) reactions to store and release heat. In the storage step, hot air from the solar receiver is used to reduce the oxidation state of an oxide cation, e.g. Fe3+ to Fe2+. Heat energy is thus stored as chemical bonds and the oxide is charged. To discharge the stored energy, the reduced oxide is re-oxidized in air and heat is released. Air is used as both the heat transfer fluid and reactant and no storage of fluid is needed. This project investigated the engineering and economic feasibility of this proposed TES concept. The DOE storage cost and LCOE targets are $15/kWh and $0.09/kWh respectively. Sixteen pure oxide cycles were identified through thermodynamic calculations and literature information. Data showed the kinetics of re-oxidation of the various oxides to be a key barrier to implementing the proposed concept. A down selection was carried out based on operating temperature, materials costs and preliminary laboratory measurements. Cobalt oxide, manganese oxide and barium oxide were selected for developmental studies to improve their REDOX reaction kinetics. A novel approach utilizing mixed oxides to improve the REDOX kinetics of the selected oxides was proposed. It partially

  10. BH4 treatment in BH4-responsive PKU patients : Preliminary data on blood prolactin concentrations suggest increased cerebral dopamine concentrations

    NARCIS (Netherlands)

    van Vliet, Danique; Anjema, Karen; Jahja, Rianne; de Groot, Martijn J; Liemburg, Geertje B; Heiner-Fokkema, Rebecca; van der Zee, Eddy A; Derks, Terry G J; Kema, Ido P; van Spronsen, Francjan J


    In phenylketonuria (PKU), cerebral neurotransmitter deficiencies have been suggested to contribute to brain dysfunction. Present treatment aims to reduce blood phenylalanine concentrations by a phenylalanine-restricted diet, while in some patients blood phenylalanine concentrations also respond to c

  11. Image cytometer method for automated assessment of human spermatozoa concentration

    DEFF Research Database (Denmark)

    Egeberg, D L; Kjaerulff, S; Hansen, C


    to investigator bias. Here we show that image cytometry can be used to accurately measure the sperm concentration of human semen samples with great ease and reproducibility. The impact of several factors (pipetting, mixing, round cell content, sperm concentration), which can influence the read-out as well......In the basic clinical work-up of infertile couples, a semen analysis is mandatory and the sperm concentration is one of the most essential variables to be determined. Sperm concentration is usually assessed by manual counting using a haemocytometer and is hence labour intensive and may be subjected...... and easy measurement of human sperm concentration....

  12. Derivation of Rouse equation for sediment concentration using Shannon entropy (United States)

    Kumbhakar, Manotosh; Ghoshal, Koeli; Singh, Vijay P.


    Sediment concentration is fundamental for determining sediment transport in open channels. The Rouse equation, one of several methods for computing sediment concentration, has been derived using deterministic hydraulic principles. This study derives the Rouse equation using the Shannon entropy theory. The derivation requires a hypothesis on the cumulative probability distribution function of sediment concentration in terms of flow depth which is formulated in a general form and can specialize in several specific forms reported in the literature. The advantage of using the entropy theory is that it permits quantification of uncertainty associated with concentration and determination of parameters in terms of specified information, such as mean concentration.

  13. Prevention of febrile nonhemolytic transfusion reaction with leucocyte filtrated concentrates

    Institute of Scientific and Technical Information of China (English)

    ZHAO Shu-ming; XIANG Guo-chun; ZHANG Jia-si; CHENG Xiao-ling; LI Ru-qing


    Objective: To assess the clinical efficiency of the transfusion of leucocyte filtrated RBC concentrates to prevent febrile nonhemolytic transfusion reactions (FNHTRs). Methods: One hundred patients with liver cirrhosis, gastric ulcer or cancer were subjected to receive RBC concentrates after leucocyte filtration.Another 50 patients with similar diseases were selected to receive non-filtrated RBC concentrates. The incidence of FNHTRs in all patients was investigated. Results: There was no FNHTR in 100 transfusions with leucocyte filtrated RBC concentrates, while FNHTRs occurred in 8 of 50 patients with non-filtrated RBC concentrates, with the incidence of 160%. Conclusion: FNHTRs to RBC transfusion can be prevented with leucocyte filtration.

  14. Life at high salt concentrations, intracellular KCl concentrations, and acidic proteomes

    Directory of Open Access Journals (Sweden)

    Aharon eOren


    Full Text Available Extremely halophilic microorganisms that accumulate KCl for osmotic balance (the Halobacteriaceae, Salinibacter have a large excess of acidic amino acids in their proteins. This minireview explores the occurrence of acidic proteomes in halophiles of different physiology and phylogenetic affiliation. For fermentative bacteria of the order Halanaerobiales, known to accumulate KCl, an acidic proteome was predicted. However, this is not confirmed by genome analysis. The reported excess of acidic amino acids is due to a high content of Gln and Asn, which yield Glu and Asp upon acid hydrolysis. The closely related Halorhodospira halophila and Halorhodospira halochloris use different strategies to cope with high salt. The first has an acidic proteome and accumulates high KCl concentrations at high salt concentrations; the second does not accumulate KCl and lacks an acidic proteome. Acidic proteomes can be predicted from the genomes of some moderately halophilic aerobes that accumulate organic osmotic solutes (Halomonas elongata, Chromohalobacter salexigens and some marine bacteria. Based on the information on cultured species it is possible to understand the pI profiles predicted from metagenomic data from hypersaline environments.

  15. Compact Flyeye concentrator with improved irradiance uniformity on solar cell (United States)

    Zhuang, Zhenfeng; Yu, Feihong


    A Flyeye concentrator with improved irradiance distribution on the solar cell in a concentrator photovoltaic system is proposed. This Flyeye concentrator is composed of four surfaces: a refractive surface, mirror surface, freeform surface, and transmissive surface. Based on the principles of geometrical optics, the contours of the proposed Flyeye concentrator are calculated according to Fermat's principle, the edge-ray principle, and the ray reversibility principle without solving partial differential equations or using an optimization algorithm, therefore a slope angle control method is used to construct the freeform surface. The solid model is established by applying a symmetry of revolution around the optical axis. Additionally, the optical performance for the Flyeye concentrator is simulated and analyzed by Monte-Carlo method. Results show that the Flyeye concentrator optical efficiency of >96.2% is achievable with 1333× concentration ratio and ±1.3 deg acceptance angle, and 1.3 low aspect ratio (average thickness to entry aperture diameter ratio). Moreover, comparing the Flyeye concentrator specification to that of the Köhler concentrator and the traditional Fresnel-type concentrator, results indicate that this concentrator has the advantages of improved uniformity, reduced thickness, and increased tolerance to the incident sunlight.

  16. Selection of antibiotic resistance at very low antibiotic concentrations. (United States)

    Sandegren, Linus


    Human use of antibiotics has driven the selective enrichment of pathogenic bacteria resistant to clinically used drugs. Traditionally, the selection of resistance has been considered to occur mainly at high, therapeutic levels of antibiotics, but we are now beginning to understand better the importance of selection of resistance at low levels of antibiotics. The concentration of an antibiotic varies in different body compartments during treatment, and low concentrations of antibiotics are found in sewage water, soils, and many water environments due to natural production and contamination from human activities. Selection of resistance at non-lethal antibiotic concentrations (below the wild-type minimum inhibitory concentration) occurs due to differences in growth rate at the particular antibiotic concentration between cells with different tolerance levels to the antibiotic. The minimum selective concentration for a particular antibiotic is reached when its reducing effect on growth of the susceptible strain balances the reducing effect (fitness cost) of the resistance determinant in the resistant strain. Recent studies have shown that resistant bacteria can be selected at concentrations several hundred-fold below the lethal concentrations for susceptible cells. Resistant mutants selected at low antibiotic concentrations are generally more fit than those selected at high concentrations but can still be highly resistant. The characteristics of selection at low antibiotic concentrations, the potential clinical problems of this mode of selection, and potential solutions will be discussed.

  17. Salt Concentration Differences Alter Membrane Resistance in Reverse Electrodialysis Stacks

    KAUST Repository

    Geise, Geoffrey M.


    Membrane ionic resistance is usually measured by immersing the membrane in a salt solution at a single, fixed concentration. While salt concentration is known to affect membrane resistance when the same concentration is used on both sides of the membrane, little is known about membrane resistance when the membrane is placed between solutions of different concentrations, such as in a reverse electrodialysis (RED) stack. Ionic resistance measurements obtained using Selemion CMV and AMV that separated sodium chloride and ammonium bicarbonate solutions of different concentrations were greater than those measured using only the high-concentration solution. Measured RED stack resistances showed good agreement with resistances calculated using an equivalent series resistance model, where the membranes accounted for 46% of the total stack resistance. The high area resistance of the membranes separating different salt concentration solutions has implications for modeling and optimizing membranes used in RED systems.

  18. Biodegradation of PAHs in Soil: Influence of Initial PAHs Concentration (United States)

    Kamil, N. A. F. M.; Talib, S. A.


    Most studies on biodegradation of Polycyclic Aromatic Hydrocarbons (PAHs) evaluate the effect of initial PAHs concentration in liquid medium. There are limited studies on evaluation in solid medium such as contaminated soil. This study investigated the potential of the bacteria, Corynebacterium urealyticum isolated from municipal sludge in degrading phenanthrene contaminated soil in different phenanthrene concentration. Batch experiments were conducted over 20 days in reactors containing artificially contaminated phenanthrene soil at different concentration inoculated with a bacterial culture. This study established the optimum condition for phenanthrene degradation by the bacteria under nonindigenous condition at 500 mg/kg of initial phenanthrene concentration. High initial concentration required longer duration for biodegradation process compared to low initial concentration. The bacteria can survive for three days for all initial phenanthrene concentrations.

  19. Ownership concentration, choice of auditors, and firm performance

    DEFF Research Database (Denmark)

    Farooq, Omar; El Kacemi, Youssef


    How does ownership concentration effect firm performance in emerging markets? On one hand, concentrated ownership leads to higher agency problems, and on the other hand, it minimizes agency problems by removing the free-rider problem. Using a large dataset of ownership concentration from the MENA...... region during the period between 2004 and 2008, we document that ownership concentration, as itself, may not have a significant impact on firm performance. It is, rather, the way concentrated firms govern themselves that determine their performance. We argue that concentrated ownership firms, being aware...... of the agency problems embedded in their ownership structure, appoint one of big-four auditors as their external auditor to signal the market that they are disclosing reliable information. Our results also show a significantly positive relationship between ownership concentration and the choice of auditor. We...

  20. Working fluid concentration measurement in solar air conditioning systems

    Energy Technology Data Exchange (ETDEWEB)

    Romero, R.J.; Basurto-Pensado, M.A. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001. Col. Chamilpa, C.P. 62210, Cuernavaca, Morelos (Mexico); Jimenez-Heredia, A.H.; Sanchez-Mondragon, J.J. [Departamento de Optica, Instituto Nacional de Astrofisica Optica y Electronica, Luis Enrique Erro No. 1, Tonantzintla, Apartado Postal 51 y 216, C.P. 72000, Puebla (Mexico)


    In order to evaluate on-line corrosive electrolyte concentration in solar air conditioning systems, an optical technique to determine the concentration is being proposed. With this optical sensing method, it is possible to measure the percentage concentration of the aqueous corrosive lithium bromide solution at temperatures ranging from 25{sup o}C to 70{sup o}C and a maximum concentration of 60%. The measurement system is based on the refractive index of the solution and the data correlation, at several temperature and concentration values. The results of this work present a direct method for concentration measurement of corrosive liquids and also show the correlation among the three parameters: refractive index, temperature and weight concentration. This correlation can be used to develop the optical device for solar air conditioning systems to control and improve efficiency. (author)

  1. Refractive Secondary Solar Concentrator Demonstrated High-Temperature Operation (United States)

    Wong, Wayne A.


    Space applications that utilize solar thermal energy--such as electric power conversion systems, thermal propulsion systems, and furnaces--require highly efficient solar concentration systems. The NASA Glenn Research Center is developing the refractive secondary concentrator, which uses refraction and total internal reflection to efficiently concentrate and direct solar energy. When used in combination with advanced lightweight primary concentrators, such as inflatable thin films, the refractive secondary concentrator enables very high system concentration ratios and very high temperatures. Last year, Glenn successfully demonstrated a secondary concentrator throughput efficiency of 87 percent, with a projected efficiency of 93 percent using an antireflective coating. Building on this achievement, Glenn recently successfully demonstrated high-temperature operation of the secondary concentrator when it was used to heat a rhenium receiver to 2330 F. The high-temperature demonstration of the concentrator was conducted in Glenn's 68-ft long Tank 6 thermal vacuum facility equipped with a solar simulator. The facility has a rigid panel primary concentrator that was used to concentrate the light from the solar simulator onto the refractive secondary concentrator. NASA Marshall Space Flight Center provided a rhenium cavity, part of a solar thermal propulsion engine, to serve as the high-temperature receiver. The prototype refractive secondary concentrator, measuring 3.5 in. in diameter and 11.2 in. long, is made of single-crystal sapphire. A water-cooled splash shield absorbs spillage light outside of the 3.5-in. concentrator aperture. Multilayer foil insulation composed of tungsten, molybdenum, and niobium is used to minimize heat loss from the hightemperature receiver. A liquid-cooled canister calorimeter is used to measure the heat loss through the multilayer foil insulation.

  2. Effects of fruit thinning on fruit drop, leaf carbohydrates concentration, fruit carbohydrates concentration, leaf nutrient concentration and fruit quality in Pummelo cultivar Thong Dee

    Directory of Open Access Journals (Sweden)

    Pongnart Nartvaranant


    Full Text Available The effects of fruit thinning on fruit drop, leaf carbohydrates concentration, fruit carbohydrates concentration, leaf nutrient concentration and fruit quality in pummelo cultivar Thong Dee growing in Nakhon Pathom province, Thailand, were studied during January-August 2013. The results showed that 50% fruit thinning by hand at 1 month after fruit set increased percent of fruit retention throughout fruit development. At 2 month after fruit set, 50% fruit thinning gave 62% of fruit retention, which were significantly higher than no thinning (36.60%, whereas, 50% fruit thinning gave 40% of fruit retention at 6 month after fruit set, which significantly higher than no thinning (20.2%. A significant difference in leaf carbohydrate concentration was found in 3-6 month after fruit set. At 3 months after fruit set, 50% fruit thinning gave significantly higher leaf carbohydrate concentration (81.80 mg.g-1 than no thinning (73.56 mg.g-1, whereas, at 6 month after fruit set, 50% fruit thinning gave significantly higher leaf carbohydrate concentration (128.92 mg.g-1 than no thinning (102.90 mg.g-1. Although, 50% fruit thinning gave no effect on peel and pulp dry weight including peel and pulp carbohydrates concentration during fruit development. For plant nutrient analysis, 50% fruit thinning gave significantly higher leaf nitrogen (N, phosphorus (P and potassium (K concentration than no thinning during 3-6 month after fruit set. However, 50% fruit thinning had no effect on fruit weight, fruit circumstance, fruit diameter, titratable acidity (TA and total soluble solid (TSS. It was concluded that 50% fruit thinning increased percent of fruit retention and may have an effect on the accumulation of leaf carbohydrates, leaf N, leaf P and leaf K concentrations in pummelo cultivar Thong Dee.

  3. Critical Retrospect on Conventional and Luminescent Solar Concentration Devices

    Directory of Open Access Journals (Sweden)

    Hamzah Abdul-Rahman


    Full Text Available Problem statement: Conventional solar concentrators are only sensitive for the beam radiation and they function poorly in overcast sky conditions. Even under a clear sky condition, trackers are always needed for conventional solar concentrators. Static concentrators always come with a poor concentration rate without a tracker and the light concentrated by normal Luminescent Solar Concentrators (LSC could not be transported by optical fibers to a remote place since the light produced by LSCs is not a pointolite. Approach: Through a critical literature review and discussion, this article retrospects the merits and demerits of recent conventional solar concentrators and Luminescent Solar Concentrators (LSC. Results: Results summarized the limitations in current day lighting related solar concentration devices. As an approach for energy saving, daylight has a disadvantage of not being able to reach many areas of a building such as store rooms, basements and corridors and it also brings heat gain with the light. Light pipes were designed to transport daylight to unreached areas, but light pipes have their difficulties for wiring, so that optical fibers are considered as the best approach for the daylight transportation so far. However, the optical fiber needs a pointolite for the light transportation. Various solar concentrators that were designed using optical approaches such as using mirrors or lens for the solar energy concentration. Since they are only sensitive for the beam irradiation, they function poorly in the cloudy weather and the diffuse light conditions and even if they are under a clear sky condition, trackers are always needed. Luminescent Solar Concentrators (LSC and some static solar concentrators were then designed as the diffuse light solution and the static solution, respectively. Static concentrators always come with a low concentration rate without a tracker and the light concentrated by normal LSCs could not

  4. Simulation and development of a multi-leg homogeniser concentrating assembly for concentrated photovoltaic (CPV) system with electrical rating analysis

    KAUST Repository

    Burhan, Muhammad


    Concentrated photovoltaic (CPV) system utilizing multi-junction solar cells, is the main focus for current research, offering highest efficiency among all photovoltaic systems. The main aspect of CPV system is the design and performance of concentrating assembly, as it determines the performance of whole CPV system. However, the conventional design of CPV concentrating assembly dedicates one concentrator for each solar cell, in which single concentrator is capable to concentrate solar radiation onto single solar cell. This paper proposes a novel concentrating assembly for CPV system, which is designed to concentrate solar radiation onto four multi-junction solar cells with a single set of concentrators. The proposed design not only can reduce the number of concentrators and assembly efforts for CPV systems, but also achieved an acceptance angle of 1°. In this paper, the proposed multi-leg homogeniser CPV concentrating assembly is designed, developed, experimentally tested and verified through ray tracing simulation. The paper also discuss the development of mini, precise and accurate but cost effective two axis solar tracker for CPV system, which can be installed at any location even at rooftop of residential buildings, unlike conventional large scale CPV systems. Moreover, through the electrical rating analysis of the developed CPV system, its performance can be accurately estimated in any region. © 2016 Elsevier Ltd. All rights reserved.

  5. Influence of concentration polarization on DNA translocation through a nanopore (United States)

    Zhai, Shengjie; Zhao, Hui


    Concentration polarization can be induced by the unique ion-perm selectivity of small nanopores, leading to a salt concentration gradient across nanopores. This concentration gradient can create diffusio-osmosis and induce an electric field, affecting ionic currents on DNA that translocates through a nanopore. Here this influence is theoretically investigated by solving the continuum Poisson-Nernst-Planck model for different salt concentrations, DNA surface charge densities, and pore properties. By implementing the perturbation method, we can explicitly compute the contribution of concentration polarization to the ionic current. The induced electric field by concentration polarization is opposite to the imposed electric field and decreases the migration current, and the induced diffusio-osmosis can decrease the convection current as well. Our studies suggest that the importance of the concentration polarization can be determined by the parameter λ /G where λ is the double-layer thickness and G is the gap size. When λ /G is larger than a critical value, the influence of concentration polarization becomes more prominent. This conclusion is supported by the studies on the dependence of the ionic current on salt concentration and pore properties, showing that the difference between two models with and without accounting for concentration polarization is larger for low salts and small pores, which correspond to larger λ /G .

  6. Fine particulate concentrations on sidewalks in five Southern California cities (United States)

    Boarnet, Marlon G.; Houston, Douglas; Edwards, Rufus; Princevac, Marko; Ferguson, Gavin; Pan, Hansheng; Bartolome, Christian


    This research provides an exploratory examination of the factors associated with fine particle concentrations in intersection and sidewalk microenvironments in five study areas in the Los Angeles region. The study areas range from low-density, auto-oriented development patterns to dense urban areas with mid- and high-rise buildings. Average concentrations of FP DT (fine particle concentrations measured with DustTrak Aerosol Monitors) ranged from about 20 to 70 μg m -3 across study areas during stationary and mobile (walking) monitoring in morning, midday, and evening periods. Results suggest that fine particle concentrations are highly variable on urban sidewalks. A regression analysis shows that concentrations are associated with traffic and the proximate built environment characteristics after accounting for meteorological factors, time of day, and location in the region. Regressions show higher concentrations were associated with lower wind speeds and higher temperatures, higher adjacent passenger vehicle traffic, higher ambient concentrations, and street canyons with buildings of over five stories. Locations in street canyons with 2-5 story buildings and with more paving and open space had lower concentrations after accounting for other factors. The associations with traffic and built environment variables explained a small amount of the variation in FP DT concentrations, suggesting that future research should examine the relative role of localized traffic and built environment characteristics compared to regional ambient concentrations and meteorology.

  7. Increasing concentrations of arsenic and vanadium in (southern) Swedish streams

    Energy Technology Data Exchange (ETDEWEB)

    Waellstedt, Teresia, E-mail: [Department of Aquatic Sciences and Assessment, SLU (Swedish University of Agricultural Sciences), P.O. Box 7050, SE-750 07 Uppsala (Sweden); Bjoerkvald, Louise [Department of Aquatic Sciences and Assessment, SLU (Swedish University of Agricultural Sciences), P.O. Box 7050, SE-750 07 Uppsala (Sweden); Gustafsson, Jon Petter [Department of Land and Water Resources Engineering, KTH (Royal Institute of Technology), Teknikringen 76, SE-100 44 Stockholm (Sweden)


    The aim of this study was to investigate temporal trends and controlling factors of As and V in running waters throughout Sweden. For this purpose, data on stream water chemistry from 62 streams of varying catchment size and characteristics, included in the Swedish environmental monitoring programmes were evaluated. The geochemical software Visual MINTEQ was used to model the speciation and trend analyses were performed on total concentrations of As and V as well as modelled fractions (dissolved species as well as arsenate and vanadate adsorbed to ferrihydrite). The trend analyses showed increasing total concentrations of As and V in southern Sweden. Concentrations of As and V correlated significantly to Fe concentrations in 59 and 60 of the 62 streams respectively, indicating that Fe is an important determining factor for As and V concentrations in Swedish streams. This was confirmed by the geochemical modelling that indicated that the adsorbed fraction is the dominant form of As and V and that the concentrations of As and V in Swedish streams are thus highly determined by concentrations of colloidal or particulate Fe. It is therefore suggested that the increasing trends of As and V are to a large extent due to increasing concentrations of colloidal Fe, which is stabilised by increasing concentrations of DOC. Further the geochemical modelling indicates that the dissolved fraction of As and V generally is small, with the exception of a few streams with high pH and/or phosphate concentrations.

  8. Recovery of alicyclobacillus from inhibitory fruit juice concentrates. (United States)

    McNamara, Christopher J; Wiebe, Deborah; Gomez, Margarita


    Growth of Alicyclobacillus in low-pH fruit juices may result in off-odors and off-flavors due to the production of compounds such as guaiacol (2-methoxy phenol). An important step in preventing Alicyclobacillus contamination of fruit juices is the screening of incoming ingredients. Many fruit juice concentrates contain compounds that inhibit Alicyclobacillus growth, but beverages produced from the concentrates may not contain sufficient amounts of the active component to prevent spoilage. Therefore, accurate screening of juice concentrates is essential to prevent false-negative test results and product spoilage. The objective of this study was to evaluate isolation methods for detection of Alicyclobacillus in inhibitory juice concentrates. Recovery of Alicyclobacillus spores from inoculated and naturally contaminated concentrates was compared by using pour plate, spread plate, and filtration methods. Pour plates consistently recovered the lowest number of spores from inoculated concentrates. Spread plating was the most effective method used to recover spores from inoculated apple and pomegranate juice concentrates, while filtration resulted in the highest recovery from cranberry concentrate. When tested on naturally contaminated concentrates, the pour plate method failed to detect Alicyclobacillus in many samples. Filtration was much more effective. The filtration method increased the likelihood of detecting Alicyclobacillus contamination of fruit juice concentrates containing inhibitory compounds.

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

    Directory of Open Access Journals (Sweden)

    Stefanović Velimir P.


    Full Text Available 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 conversion of solar radiation into heat. The working fluid is water with laminar flow through a copper pipe surrounded by an evacuated glass layer. Based on the physical model, a mathematical model is introduced, which consists of energy balance equations for four collector components. In this paper, water temperatures in flow directions are numerically predicted, as well as temperatures of relevant P2CC collector components for various values of input temperatures and mass flow rates of the working fluid, and also for various values of direct sunlight radiation and for different collector lengths. The device which is used to transform solar energy to heat is referred to as solar collector. This paper gives numerical estimated changes of temperature in the direction of fluid flow for different flow rates, different solar radiation intensity and different inlet fluid temperatures. The increase in fluid flow reduces output temperature, while the increase in solar radiation intensity and inlet water temperature increases output temperature of water. Furthermore, the dependence on fluid output temperature is determined, along with the current efficiency by the number of nodes in the numerical calculation.

  10. Beam-Forming Concentrating Solar Thermal Array Power Systems (United States)

    Cwik, Thomas A. (Inventor); Dimotakis, Paul E. (Inventor); Hoppe, Daniel J. (Inventor)


    The present invention relates to concentrating solar-power systems and, more particularly, beam-forming concentrating solar thermal array power systems. A solar thermal array power system is provided, including a plurality of solar concentrators arranged in pods. Each solar concentrator includes a solar collector, one or more beam-forming elements, and one or more beam-steering elements. The solar collector is dimensioned to collect and divert incoming rays of sunlight. The beam-forming elements intercept the diverted rays of sunlight, and are shaped to concentrate the rays of sunlight into a beam. The steering elements are shaped, dimensioned, positioned, and/or oriented to deflect the beam toward a beam output path. The beams from the concentrators are converted to heat at a receiver, and the heat may be temporarily stored or directly used to generate electricity.

  11. Serum Vaccine Antibody Concentrations in Adolescents Exposed to Perfluorinated Compounds

    DEFF Research Database (Denmark)

    Grandjean, Philippe; Heilmann, Carsten; Weihe, Pal


    BACKGROUND: Postnatal exposure to perfluorinated alkylate substances (PFASs) is associated with lower serum concentrations of specific antibodies against certain childhood vaccines at age 7 years. OBJECTIVES: We prospectively followed a Faroese birth cohort to determine these associations at age 13...... of 202 children showed higher vaccine antibody concentrations at age 13 than at age 7. Separate analyses were therefore conducted after exclusion of these two subgroups. Diphtheria antibody concentrations decreased at elevated PFAS concentrations at ages 13 and 7 years, associations being statistically...... applied to determine the association between postnatal PFAS exposures and antibody concentrations. RESULTS: Serum concentrations of PFASs and antibodies generally declined from age 7 to age 13. However, 68 subjects had visited the emergency room and likely received a vaccination booster, and a total...

  12. Fresnel Concentrators for Space Solar Power and Solar Thermal Propulsion (United States)

    Bradford, Rodney; Parks, Robert W.; Craig, Harry B. (Technical Monitor)


    Large deployable Fresnel concentrators are applicable to solar thermal propulsion and multiple space solar power generation concepts. These concentrators can be used with thermophotovoltaic, solar thermionic, and solar dynamic conversion systems. Thin polyimide Fresnel lenses and reflectors can provide tailored flux distribution and concentration ratios matched to receiver requirements. Thin, preformed polyimide film structure components assembled into support structures for Fresnel concentrators provide the capability to produce large inflation-deployed concentrator assemblies. The polyimide film is resistant to the space environment and allows large lightweight assemblies to be fabricated that can be compactly stowed for launch. This work addressed design and fabrication of lightweight polyimide film Fresnel concentrators, alternate materials evaluation, and data management functions for space solar power concepts, architectures, and supporting technology development.

  13. Assessment of cadmium (Cd) concentration in arable soil in China. (United States)

    Zhang, Xiuying; Chen, Dongmei; Zhong, Taiyang; Zhang, Xiaomin; Cheng, Min; Li, Xinhui


    Cadmium (Cd) concentration in arable soil has drawn broad public attention due to its direct effect on Cd concentration in food. However, there have been few studies of surveying Cd accumulation on the national scale in China. This paper collected 486 studies of Cd concentrations in Chinese arable soil. The results showed that the average Cd concentration was 0.27 mg/kg, higher than its background value, indicating that Cd had been introduced into arable soil by human activity. The Cd concentrations in areas of mining and smelting, urban areas, and areas irrigated by wastewater were obviously higher than that in remote areas. Spatially, Cd concentrations were lower in the north than those in the south, and many hotspots existed throughout China due to mining and smelting activities. Most Cd in the arable soil were accumulated from external sources in all investigated provinces except Ningxia Hui Autonomous Region.

  14. Serum sialic acid and CEA concentrations in human breast cancer. (United States)

    Hogan-Ryan, A; Fennelly, J J; Jones, M; Cantwell, B; Duffy, M J


    The concentration of bound sialic acid in the sera of 56 normal subjects and 65 subjects with breast cancer was measured, in order to determine (1) whether serum sialic acid concentrations are raised in breast cancer and (2) whether the concentration of sialic acid in serum reflects tumour stage. The amount of sialic acid in serum was compared to serum carcinoembryonic antigen (CEA) values. Urinary hydroxyproline and serum alkaline phosphatase concentrations were used as indicators of bone and liver involvement. Erythrocyte sedimentation rate (ESR) was also measured. Significantly elevated serum sialic acid concentrations were found in breast cancer, and showed correlation with tumour stage. Serum sialic acid values did not correlate with CEA values. The results suggest that measurement of serum sialic acid concentrations may be of adjunctive value in assessing tumour stage.

  15. Forecasting ultrafine particle concentrations from satellite and in situ observations (United States)

    Crippa, P.; Castruccio, S.; Pryor, S. C.


    Recent innovations in remote sensing technologies and retrievals offer the potential for predicting ultrafine particle (UFP) concentrations from space. However, the use of satellite observations to provide predictions of near-surface UFP concentrations is limited by the high frequency of incomplete predictor values (due to missing observations), the lack of models that account for the temporal dependence of UFP concentrations, and the large uncertainty in satellite retrievals. Herein we present a novel statistical approach designed to address the first two limitations. We estimate UFP concentrations by using lagged estimates of UFP and concurrent satellite-based observations of aerosol optical properties, ultraviolet solar radiation flux, and trace gas concentrations, wherein an expectation maximization algorithm is used to impute missing values in the satellite observations. The resulting model of UFP (derived by using an autoregressive moving average model with exogenous inputs) explains 51 and 28% of the day-to-day variability in concentrations at two sites in eastern North America.

  16. Fundamental and practical limits of planar tracking solar concentrators. (United States)

    Grede, Alex J; Price, Jared S; Giebink, Noel C


    Planar microtracking provides an alternate paradigm for solar concentration that offers the possibility of realizing high-efficiency embedded concentrating photovoltaic systems in the form factor of standard photovoltaic panels. Here, we investigate the thermodynamic limit of planar tracking optical concentrators and establish that they can, in principal, achieve the sine limit of their orientationally-tracked counterparts provided that the receiver translates a minimum distance set by the field of view half-angle. We develop a phase space methodology to optimize practical planar tracking concentrators and apply it to the design of a two surface, catadioptric system that operates with > 90% optical efficiency over a 140° field of view at geometric gains exceeding 1000×. These results provide a reference point for subsequent developments in the field and indicate that planar microtracking can achieve the high optical concentration ratio required in commercial concentrating photovoltaic systems.

  17. Nonimaging fresnel lenses. Design and performance of solar concentrators

    Energy Technology Data Exchange (ETDEWEB)

    Leutz, R. [Tokyo Univ. of Agriculture and Technology, Koganei-shi (Japan). BASE; Suzuki, A. [UNESCO, Paris (France). Natural Science Sector


    This book offers a detailed and comprehensive account of the engineering of the world's first nonimaging Fresnel lens solar concentrator. The book closes a gap in solar concentrator design, and describes nonimaging refractive optics and its numerical mathematics. The contents follow a systems approach that is absent in standard handbooks of optics or solar energy. The reader is introduced to the principles, theories, and advantages of nonimaging optics from the standpoint of concentrating sunlight (the solar concentrator idea). The book shows the reader how to find his or her own optical solution using the rules and methodologies covering the design and the assessment of the nonimaging lens. This novel solar concentrator is developed within the natural constraints presented by the sun and in relation to competitive solutions offered by other concentrators. (orig.)

  18. Study of Cellulose Interaction with Concentrated Solutions of Sulfuric Acid


    Michael Ioelovich


    The effect of the concentration of sulfuric acid (SA) and temperature on structure and properties of cellulose (MCC) had been studied. Investigations showed that solubility of the initial sample at the room temperature increased gradually in the range of the acid concentration from 50 to 60 wt.% SA. When SA concentration reached 65 wt.%, then MCC sample dissolved completely. Cellulose regenerated from 65 wt.% SA had an amorphized structure and was characterized by high enzymatic digestibility...

  19. An Automatic High Efficient Method for Dish Concentrator Alignment


    Yong Wang; Song Li; Jinshan Xu; Yijiang Wang; Xu Cheng; Changgui Gu; Shengyong Chen; Bin Wan


    Alignment of dish concentrator is a key factor to the performance of solar energy system. We propose a new method for the alignment of faceted solar dish concentrator. The isosceles triangle configuration of facet’s footholds determines a fixed relation between light spot displacements and foothold movements, which allows an automatic determination of the amount of adjustments. Tests on a 25 kW Stirling Energy System dish concentrator verify the feasibility, accuracy, and efficiency of our...

  20. Does Market Concentration Preclude Risk Taking in Baking?


    Kaniska Dam; Santiago Sanchez Pages


    We analyse risk-taking behaviour of banks in the context of a model based on spatial competition. Banks mobilise deposits by offering deposit rates. We show that when the market concentration is low, banks invest in the gambling asset. On the other hand, for sufficiently high levels of market concentration, all banks choose the prudent asset to invest in, and some depositors may even be left out of the market. Our results suggest a discontinuous relation between market concentration and socia...

  1. Interpolation of steady-state concentration data by inverse modeling. (United States)

    Schwede, Ronnie L; Cirpka, Olaf A


    In most groundwater applications, measurements of concentration are limited in number and sparsely distributed within the domain of interest. Therefore, interpolation techniques are needed to obtain most likely values of concentration at locations where no measurements are available. For further processing, for example, in environmental risk analysis, interpolated values should be given with uncertainty bounds, so that a geostatistical framework is preferable. Linear interpolation of steady-state concentration measurements is problematic because the dependence of concentration on the primary uncertain material property, the hydraulic conductivity field, is highly nonlinear, suggesting that the statistical interrelationship between concentration values at different points is also nonlinear. We suggest interpolating steady-state concentration measurements by conditioning an ensemble of the underlying log-conductivity field on the available hydrological data in a conditional Monte Carlo approach. Flow and transport simulations for each conditional conductivity field must meet the measurements within their given uncertainty. The ensemble of transport simulations based on the conditional log-conductivity fields yields conditional statistical distributions of concentration at points between observation points. This method implicitly meets physical bounds of concentration values and non-Gaussianity of their statistical distributions and obeys the nonlinearity of the underlying processes. We validate our method by artificial test cases and compare the results to kriging estimates assuming different conditional statistical distributions of concentration. Assuming a beta distribution in kriging leads to estimates of concentration with zero probability of concentrations below zero or above the maximal possible value; however, the concentrations are not forced to meet the advection-dispersion equation.

  2. A viscometric method of measuring plasma fibrinogen concentrations.


    Ernst, E.; Resch, K L; Saradeth, T.; A. Maier; Matrai, A


    A technique based on deducing the viscosity of serum from that of plasma was compared with the commonly used Clauss method. The two methods correlated closely (r = 0.914). The reproducibility of the viscometric method was slightly poorer than the Clauss technique at low fibrinogen concentrations, equal to that at medium fibrinogen concentrations, and marginally better at high concentrations. Fibrinogen can therefore be measured reasonably accurately with the viscometric method, and can be rec...

  3. Distribution and concentration of cyclosporin in human blood.


    Atkinson, K.; Britton, K; Biggs, J.


    In patients receiving cyclosporin to minimise graft versus host disease after allogeneic bone marrow transplantation, whole blood cyclosporin concentration was roughly twice the serum concentration when blood was separated at 37 degrees C. In turn, blood separation at 37 degrees C resulted in a doubling of serum cyclosporin concentration compared with separation at room temperature. In vitro studies showed that the latter phenomenon was due to a temperature dependent partitioning of cyclospor...

  4. The concentration of ammonia regulates nitrogen metabolism in Saccharomyces cerevisiae.


    ter Schure, E G; Silljé, H H; Verkleij, A J; Boonstra, J; Verrips, C T


    Saccharomyces cerevisiae was grown in a continuous culture at a single dilution rate with input ammonia concentrations whose effects ranged from nitrogen limitation to nitrogen excess and glucose limitation. The rate of ammonia assimilation (in millimoles per gram of cells per hour) was approximately constant. Increased extracellular ammonia concentrations are correlated with increased intracellular glutamate and glutamine concentrations, increases in levels of NAD-dependent glutamate dehydro...

  5. Concentrations of boron, molybdenum, and selenium in chinook salmon (United States)

    Hamilton, Steven J.; Wiedmeyer, Raymond H.


    The concentrations of boron, molybdenum, and selenium in young chinook salmon Oncorhynchus tshawytscha were determined in three partial life cycle chronic toxicity studies. In each study, fish were exposed to a mixture of boron, molybdenum, selenate, and selenite in the proportions found in subsurface agricultural drainage water in the basin of the San Joaquin Valley, California. Tests were conducted in well water and in site-specific fresh and brackish waters. No boron or molybdenum was detected in fish exposed to concentrations as high as 6,046 μg boron/L and 193 μg molybdenum/L for 90 d in well water or fresh water; however, whole-body concentrations of selenium increased with increasing exposure concentrations in well water and fresh water, but not in brackish water. Concentrations of selenium in chinook salmon were strongly correlated with reduced survival and growth of fish in well water and with reduced survival in a 15-d seawater challenge test of fish from fresh water. Concentrations of selenium in fish seemed to reach a steady state after 60 d of exposure in well water or fresh water. Fish in brackish water had only background concentrations of selenium after 60 d of exposure, and no effects on survival and growth in brackish water or on survival in a 10-d seawater challenge test were exhibited. This lack of effect in brackish water was attributed to initiation of the study with advanced fry, which were apparently better able to metabolize the trace element mixture than were the younger fish used in studies with well water and fresh water. In all three experimental waters, concentration factors (whole-body concentration/waterborne concentration) for selenium decreased with increasing exposure concentrations, suggesting decreased uptake or increased excretion, or both, of selenium at the higher concentrations.

  6. Global trends in relative and absolute wealth concentrations



    This paper compares changes in relative and absolute wealth concentrations to establish if both processes have followed similar trajectories. The findings indicate that while the level of relative wealth concentration has increased recently, it is not extraordinarily high in an historical perspective. On the contrary, the level of absolute wealth concentration is most likely higher than that previously occurred because of the increase in the wealth holdings and population size of high net wor...

  7. Cervical Collagen Concentration within Fifteen Months after Delivery

    DEFF Research Database (Denmark)

    Sundtoft, Iben; Uldbjerg, Niels; Sommer, Steffe


    OBJECTIVE: Cervical collagen concentration decreases during pregnancy. The increased risk of preterm birth following a short interpregnancy interval may be explained by an incomplete remodeling of the cervix. The objective of this study was to describe the changes in cervical collagen concentration...... was statistically significant until month 9, but not between months 9 and 12. CONCLUSIONS: Low collagen concentrations in the uterine cervix may contribute to the association between a short interpregnancy interval and preterm birth....

  8. Advances in the design of solar concentrators for thermal applications


    Canavarro, Diogo


    This thesis presents advances in the design of solar concentrators. Based on the study of the Compact Linear Fresnel Re ector Concentrator "Etendue-Matched" (CLFREM), this thesis developed optical solutions based on the Simultaneous Multiple Surface method (SMS) and new approaches of analysis of the characterizing parameters of a solar concentrator. This thesis is organized into ve sections. In the rst section (Chapters 1 and 2) an introduction to the topics addressed in t...

  9. Hydrologic and biologic influences on stream network nutrient concentrations: Interactions of hydrologic turnover and concentration-dependent nutrient uptake (United States)

    Mallard, John; McGlynn, Brian; Covino, Tim


    Stream networks lie in a crucial landscape position between terrestrial ecosystems and downstream water bodies. As such, whether inferring terrestrial watershed processes from watershed outlet nutrient signals or predicting the effect of observed terrestrial processes on stream nutrient signals, it is requisite to understand how stream networks can modulate terrestrial nutrient inputs. To date integrated understanding and modeling of physical and biological influences on nutrient concentrations at the stream network scale have been limited. However, watershed scale groundwater - surface water exchange (hydrologic turnover), concentration-variable biological uptake, and the interaction between the two can strongly modify stream water nutrient concentrations. Stream water and associated nutrients are lost to and replaced from groundwater with distinct nutrient concentrations while in-stream nutrients can also be retained by biological processes at rates that vary with concentration. We developed an empirically based network scale model to simulate the interaction between hydrologic turnover and concentration-dependent nutrient uptake across stream networks. Exchange and uptake parameters were measured using conservative and nutrient tracer addition experiments in the Bull Trout Watershed, central Idaho. We found that the interaction of hydrologic turnover and concentration-dependent uptake combined to modify and subsequently stabilize in-stream concentrations, with specific concentrations dependent on the magnitude of hydrologic turnover, groundwater concentrations, and the shape of nutrient uptake kinetic curves. We additionally found that by varying these physical and biological parameters within measured ranges we were able to generate a spectrum of stream network concentration distributions representing a continuum of shifting magnitudes of physical and biological influences on in-stream concentrations. These findings elucidate the important and variable role of

  10. Essential oil extraction with concentrating solar thermal energy


    Veynandt, François


    Material complementari del cas estudi "Essential oil extraction with concentrating solar thermal energy”, part component del llibre "Case studies for developing globally responsible engineers" Peer Reviewed

  11. Concentration-temperature superposition of helix folding rates in gelatin. (United States)

    Gornall, J L; Terentjev, E M


    Using optical rotation as the primary technique, we have characterized the kinetics of helix renaturation in water solutions of gelatin. By covering a wide range of solution concentrations we identify a universal exponential dependence of folding rate on concentration and quench temperature. We demonstrate a new concentration-temperature superposition of data at all temperatures and concentrations, and build the corresponding master curve. The normalized rate constant is consistent with helix lengthening. Nucleation of the triple helix occurs rapidly and contributes less to the helical onset than previously thought.

  12. Generation of tunable and pulsatile concentration gradients via microfluidic network

    KAUST Repository

    Zhou, Bingpu


    We demonstrate a compact Polydimethylsiloxane microfluidic chip which can quickly generate ten different chemical concentrations simultaneously. The concentration magnitude of each branch can be flexibly regulated based on the flow rate ratios of the two injecting streams. The temporal/pulsatile concentration gradients are achieved by integrating on-chip pneumatic actuated valves controlled by the external signals. The temporal concentration gradients can also be tuned precisely by varying applied frequency and duty cycle of the trigger signal. It is believed that such microdevice will be potentially used for some application areas of producing stable chemical gradients as well as allowing fast, pulsatile gradient transformation in seconds.

  13. Method and system to remove water from coal flotation concentrates

    Energy Technology Data Exchange (ETDEWEB)

    Schouterden, E.; van de Mosselaer, F.; Straggier, C.; Schlebusch, L.; Schiele, H.; von Essen, U.


    In the process for the water removal from a coal flotation concentrate water is removed together with oil which is added after the flotation steps in a centrifuge. The oil is added to the coal flotation concentrate in an amount of 0.3 wt-% of the total solids content. The solids obtained in the centrifugate are sorted and concentrated in a secondary flotation step. Prior to the flotation step flotation agents can be added to the centrifugate. After the secondary flotation step the concentrate is introduced to a decanter or a filtering device.

  14. Radon concentration in houses over a closed Hungarian uranium mine

    Energy Technology Data Exchange (ETDEWEB)

    Somlai, Janos; Kovacs, Tibor [University of Veszprem Department of Radiochemistry, H-8200, Veszprem P.O.B.: 158 (Hungary); Gorjanacz, Zoran [Mecsek Ore Environmental Protection Co. H-7614, Pecs, P.O.B.: 121 (Hungary); Varhegyi, Andras [Mecsek-OEko Environmental Protection Co. H-7614, Pecs, P.O.B.: 121 (Hungary)


    High radon concentration (average 410 kBq m{sup -3}) has been measured in a tunnel of a uranium mine, located 15-55 m below the village of Kovagoszolos, Hungary. The mine was closed in 1997; the artificial ventilation of the tunnel was then terminated and recultivation works begun. In this paper, a study has been made as to whether the tunnel has an influence on the radon concentration of surface dwellings over the mining tunnel. At different distances from the surface projection of the mining tunnel, radon concentration, the gamma dose, radon exhalation and radon concentration of soil gas were measured. The average radon concentration in the dwellings was 483 Bq m{sup -3}. Significantly higher radon concentrations (average 667 Bq m{sup -3}) were measured in houses within +/-150 m from the surface projection of the mining tunnel +50 m, compared with the houses further than the 300-m belt (average 291 Bq m{sup -3}). The average radon concentration of the soil gas was 88.8 kBq m{sup -3}, the average radon exhalation was 71.4 Bq m{sup -2} s{sup -1} and higher values were measured over the passage as well. Frequent fissures crossing the passage and running up to the surface and the high radon concentration generated in the passage (average 410 kBq m{sup -3}) may influence the radon concentration of the houses over the mining tunnel. (author)

  15. Control of Oxygen Concentration by Using a Carbonaceous Substance

    Directory of Open Access Journals (Sweden)

    Mohanad Jadan


    Full Text Available The control of oxygen concentration in gas flow may be used in chemical industry, heat power engineering, ecology, automobile construction and other industrial branches. This control is realized over a broad range of oxygen concentrations. The control of the oxygen concentration is based on passing of gas flow through a measuring cavity of radio spectrometer and measurement of a magnetic resonance signal. A change in the magnetic resonance signal of a dispersed carbonaceous substance, placed into the cavity, indicates to the changes in oxygen concentrations. The dispersed anthracite and thermal treatment cellulose substance in the oxygen-free medium are proposed to use as a carbonaceous substance.

  16. Photovoltaic concentrator technology development project. Sixth project integration meeting

    Energy Technology Data Exchange (ETDEWEB)



    Thirty-three abstracts and short papers are presented which describe the current status of research, development, and demonstration of concentrator solar cell technology. Solar concentrators discussed include the parabolic trough, linear focus Fresnel lens, point focus Fresnel lens, and the parabolic dish. Solar cells studied include silicon, GaAs, and AlGaAs. Research on multiple junction cells, combined photovoltaic/thermal collectors, back contact solar cells, and beam splitter modules is described. Concentrator solar cell demonstration programs are reported. Contractor status summaries are given for 33 US DOE concentrator solar cell contracts; a description of the project, project status, and key results to date is included. (WHK)

  17. Metal concentrations in pelagic seabirds from the North Pacific Ocean. (United States)

    Honda, K; Marcovecchio, J E; Kan, S; Tatsukawa, R; Ogi, H


    Concentrations of four essential elements (Fe, Mn, Zn, and Cu) and two toxic metals (Cd and Hg) were measured in selected tissues of 19 pelagic seabird species collected in the North Pacific and neighboring waters. Essential metal concentrations were generally highest in the liver and less variable than toxic metals among species and also within each species. Fe concentrations in the muscle were higher in Alcidae than in the other families, whereas the opposite trend was found for Fe and Mn in the liver. Zn concentrations varied among species, depending on the Cd concentrations. On the other hand, toxic metal concentrations were highest in the liver or kidney and varied widely among species, greatly depending on differences in the diet among species. Extraordinarily high Hg concentrations were found in Black-footed Albatrosses,Diomedea nigripes, exceeding 300 μg/g wet weight in some, and seemed to be due to constraints on the elimination of Hg. Also, some geographical differences in Cd and Hg concentrations of the seabirds were observed. The concentrations of Cd and Hg reported here, however, seem to be natural rather than due to environmental pollution.

  18. Effect of Surface Topography on Stress Concentration Factor

    Institute of Scientific and Technical Information of China (English)

    CHENG Zhengkun; LIAO Ridong


    Neuber rule and Arola-Ramulu model are widely used to predict the stress concentration factor of rough specimens. However, the height parameters and effective valley radius used in these two models depend strongly on the resolution of the roughness-measuring instruments and are easily introduce measuring errors. Besides, it is difficult to find a suitable parameter to characterize surface topography to quantitatively describe its effect on stress concentration factor. In order to overcome these disadvantages, profile moments are carried out to characterize surface topography, surface topography is simulated by superposing series of cosine components, the stress concentration factors of different micro cosine-shaped surface topographies are investigated by finite element analysis. In terms of micro cosine-shaped surface topography, an equation using the second profile moment to estimate the stress concentration factor is proposed, predictions for the stress concentration factor using the proposed expression are within 10% error compared with the results of finite element analysis, which are more accurate than other models. Moreover, the proposed equation is applied to the real surface topography machined by turning. Predictions for the stress concentration factor using the proposed expression are within 10% of the maximum stress concentration factors and about 5% of the effective stress concentration factors estimated from the finite element analysis for three levels of turning surface topographies under different simulated scales. The proposed model is feasible in predicting the stress concentration factors of real machined surface topographies.

  19. Soybean tocopherol concentrations are affected by crop management. (United States)

    Seguin, Philippe; Tremblay, Gilles; Pageau, Denis; Liu, Wucheng


    Soybeans are an important source of tocopherols, which have health-beneficial properties. Previous studies have demonstrated that environmental factors may affect soybean tocopherol concentrations; the impact of specific crop management strategies, however, remains poorly understood. Experiments were conducted for 2 years at three sites in Quebec to determine the impact on soybean tocopherol concentrations of seeding rate, row spacing, seeding date, cultivar, and P and K fertilization. Total and alpha-, gamma-, and delta-tocopherol concentrations were determined by high-performance liquid chromatography. Overall, alpha-tocopherol was the most responsive to the factors evaluated; the response of other tocopherols was often lower or inconsistent across environments. The seeding rate affected alpha-tocopherol concentrations in three out of five environments; seeding at a rate of 40 seeds m(-2) resulted in 4% higher concentrations than seeding at a higher rate. Wide row spacing (more than 36 cm) resulted in two out of five environments in 6% higher alpha-tocopherol concentrations as compared to narrower row spacing. The seeding date had a greater impact; mid- to late-May seeding across four environments resulted in 45% greater alpha-tocopherol concentrations than seeding at later dates. Phosphorus and K fertilization had a negligible impact on tocopherol concentrations. Across experiments, large differences were observed between environments; plants grown in northern environments consistently had lower concentrations of alpha- and gamma-tocopherols but higher concentrations of delta-tocopherol. Differences between cultivars were also consistent, ranging between 10 and 30%, depending on the tocopherol. Results demonstrate that soybean tocopherol concentrations are affected by crop management and thus suggest that specific recommended agronomic practices may need to be established for the production of soybeans for the functional food market.

  20. PCB concentrations of lake whitefish (Coregonus clupeaformis) vary by sex (United States)

    Madenjian, Charles P.; Ebener, Mark P.; Sepulveda, Maria S.


    We determined whole-fish polychlorinated biphenyl (PCB) concentrations in 26 female lake whitefish (Coregonus clupeaformis) and 34 male lake whitefish from northern Lake Huron. In 5 of the 26 female lake whitefish, we also determined PCB concentrations in the somatic tissue and ovaries. In addition, bioenergetics modeling was used to determine the contribution of the growth dilution effect to the observed difference in PCB concentrations between the sexes. Whole-fish PCB concentrations for females and males averaged 60 ng/g and 80 ng/g, respectively; thus males were 34% higher in PCB concentration compared with females. Based on the PCB determinations in the somatic tissue and ovaries, we predicted that PCB concentration of females would increase by 2.5%, on average, immediately after spawning due to release of eggs. Thus, the change in PCB concentration due to release of eggs did not explain, to any degree, the higher PCB concentrations observed in males compared with females. Bioenergetics modeling results indicated that the growth dilution effect could account for males being only 0.7% higher in PCB concentration compared with females. Thus, the growth dilution effect contributed very little to the observed difference in PCB concentrations between the sexes. We conclude that males were higher than females in PCB concentration most likely due to a higher rate of energy expenditure, stemming from greater activity and a greater resting metabolic rate. A higher rate of energy expenditure leads to a higher rate of food consumption, which, in turn, leads to a higher PCB accumulation rate.

  1. The algorithms of chlorophyll-a concentration for CMODIS

    Institute of Scientific and Technical Information of China (English)


    The algorithms of extracting chlorophyll-a (Chl-a) concentration have been established for Chinese moderate resolution imaging spectrometer (CMODIS) mounted on Shenzhou-3 spaceship launched on 25 March 2002. The CMODIS is an ocean color sensor with 30 visible channels and 4 infrared channels, much different from other ocean color satellites and needs new algorithms to process data. Three models of Chl-a concentration were established based on Chl-a data retrieved from sea-viewing wide field-of-view sensor (SeaWiFS), with the average relative errors of 26.6%, 24%.0% and 33.5%, respectively. This practical and economic approach can be used for developing the algorithms of Chinese ocean color and temperature sensor (COCTS) on the satellite Haiyang-1 to derive the Chl-a concentration concentration distribution.The applicability of the algorithms was analyzed using some in situ measurements. Suspended sediment is the main factor influencing the accuracy of the spectral ratio algorithms of Chl-a concentration. The algorithms are suitable to using in the regions where suspended sediment concentrations (SSC) are less than 5 g/m3 under the condition of relative error of Chl-a concentration retrieval within 35%. High concentration of suspended sediment leads to the overestimate remote sensing retrieval of concentration of Chl-a, while low-middle SSCs lead to the low Chl-a concentration values using the spectral ratio algorithms. Since the accuracy of Chl-a concentration by the spectral ratio algorithms is limited to waters of Case 2, it is necessary to develop semi-analytical models to improve the performance of satellite ocean color remote sensing in turbid coastal waters.

  2. Effect of breed on plasma endothelin-1 concentration, plasma renin activity, and serum cortisol concentration in healthy dogs

    DEFF Research Database (Denmark)

    Höglund, K.; Lequarré, A.-S.; Ljungvall, I.


    BACKGROUND: There are breed differences in several blood variables in healthy dogs. OBJECTIVE: Investigate breed variation in plasma endothelin-1 (ET-1) concentration, plasma renin activity, and serum cortisol concentration. ANIMALS: Five-hundred and thirty-one healthy dogs of 9 breeds examined...... blood pressure measurement, echocardiography, ECG, blood and urine analysis. RESULTS: Median ET-1 concentration was 1.29 (interquartile range [IQR], 0.97-1.82) pg/mL, median cortisol concentration 46.0 (IQR, 29.0-80.8) nmol/L, and median renin activity 0.73 (IQR, 0.48-1.10) ng/mL/h in all dogs. Overall...

  3. Gender difference in walleye PCB concentrations persists following remedial dredging (United States)

    Madenjian, Charles P.; Jude, David J.; Rediske, Richard R.; O'Keefe, James P.; Noguchi, George E.


    Eleven male walleyes (Sander vitreus) and 10 female walleyes from the Saginaw Bay (Lake Huron) population were caught during the spawning run at Dow Dam (Midland, Michigan) in the Tittabawassee River during April 1996, and individual whole-fish polychlorinated biphenyl (PCB) determinations were made. Total PCB concentrations averaged 7.95 and 3.17??mg/kg for males and females, respectively. As part of the Natural Resource Damage Assessment remediation process, contaminated sediments from the Saginaw River, the main tributary to Saginaw Bay, were removed during 2000 and 2001. Total PCB concentrations of 10 male and 10 female walleyes caught at Dow Dam during April 2007 averaged 1.58 and 0.55??mg/kg, respectively. Thus, dredging of the Saginaw River appeared to be effective in reducing PCB concentrations of Saginaw Bay adult walleyes, as both males and females decreased in PCB concentration by more than 80% between 1996 and 2007. However, the ratio of male PCB concentration to female PCB concentration did not decline between 1996 and 2007. This persistent gender difference in PCB concentrations was apparently due to a gender difference in habitat utilization coupled with a persistent spatial gradient in prey fish PCB concentrations from the Saginaw River to Lake Huron.

  4. Differences in Swallowing between High and Low Concentration Taste Stimuli

    Directory of Open Access Journals (Sweden)

    Ahmed Nagy


    Full Text Available Taste is a property that is thought to potentially modulate swallowing behavior. Whether such effects depend on taste, intensity remains unclear. This study explored differences in the amplitudes of tongue-palate pressures in swallowing as a function of taste stimulus concentration. Tongue-palate pressures were collected in 80 healthy women, in two age groups (under 40, over 60, stratified by genetic taste status (nontasters, supertasters. Liquids with different taste qualities (sweet, sour, salty, and bitter were presented in high and low concentrations. General labeled magnitude scale ratings captured perceived taste intensity and liking/disliking of the test liquids. Path analysis explored whether factors of taste, concentration, age group, and/or genetic taste status impacted: (1 perceived intensity; (2 palatability; and (3 swallowing pressures. Higher ratings of perceived intensity were found in supertasters and with higher concentrations, which were more liked/disliked than lower concentrations. Sweet stimuli were more palatable than sour, salty, or bitter stimuli. Higher concentrations elicited stronger tongue-palate pressures independently and in association with intensity ratings. The perceived intensity of a taste stimulus varies as a function of stimulus concentration, taste quality, participant age, and genetic taste status and influences swallowing pressure amplitudes. High-concentration salty and sour stimuli elicit the greatest tongue-palate pressures.

  5. Novel Fiber Optic Fluorometer for the Measurement of Alga Concentration

    Institute of Scientific and Technical Information of China (English)


    A novel fluorometer based on fiber optics is briefly introduced for the measurement of alga concentration. Both the exciting light and the fluorescence from alga chlorophyll are transmitted along a fiber cable. By this way, we can get alga concentration by measuring its chlorophyll-a fluorescence intensity. The experiment results show that this instrument is characterized by good sensitivity, linearity and accuracy.

  6. Shape Modeling of a Concentric-tube Continuum Robot

    DEFF Research Database (Denmark)

    Bai, Shaoping; Xing, Charles Chuhao


    Concentric-tube continuum robots feature with simple and compact structures and have a great potential in medical applications. The paper is concerned with the shape modeling of a type of concentric-tube continuum robot built with a collection of super-elastic NiTiNol tubes. The mechanics...

  7. Assessment of bioaerosols at a concentrated dairy operation (United States)

    Increased bioaerosol loadings in downwind plumes from concentrated animal feeding operations (CAFOs) may increase the risk for allergy and infection in humans. In this study we monitored airborne concentrations of culturable bacteria and fungi at upwind (background) and downwind sites at a 10,000 m...

  8. Elevated circulating plasma endothelin-1 concentrations in cirrhosis

    DEFF Research Database (Denmark)

    Møller, S; Emmeluth, C; Henriksen, Jens Henrik Sahl


    As endothelin-1 (ET-1), a potent vasoconstricting peptide, may play a role in the circulatory derangement and renal impairment in cirrhosis, the aim of the present study was to investigate plasma concentrations of ET-1 in different vascular beds in relation to clinical and biochemical parameters.......70, P plasma concentration between the liver, renal, or femoral...

  9. Research on the Analysis Method of Micro Concentration of Uranium

    Institute of Scientific and Technical Information of China (English)


    Spectrophotometric method is used for the analysis of micro concentration of uraninum in aqueousand organic phase in order to test the feasibility of TBP/OK-dimethylbenzene-TTA method for assayingorganic phase and concentrated hydrochloric acid-arsenazo Ⅲ method for assaying aqueous phase. It is

  10. Enacting Attention: Concentration and Shared Focus in Montessori Classrooms (United States)

    Epstein, Paul


    Concentration is a "sine qua non," a hallmark, of a Montessori Casa program. Yet, it happens that some children do not concentrate. They do not engage with the materials in the classic pattern of normalization. They are not challenged by ADD, ADHD, or a variant of sensory integration spectrum disorder. Instead of working alone, they prefer the…

  11. New luminescent materials and filters for Luminescent Solar Concentrators

    NARCIS (Netherlands)

    De Boer, D.K.G.; Ronda, C.R.; Keur, W.C.; Meijerink, A.


    In a Luminescent Solar Concentrator (LSC), short-wavelength light isconverted by a luminescent material into long-wavelength light, which is guided towards a photovoltaic cell. In principle, an LSC allows for high concentration, but in practice this is prevented by lossmechanisms like limited sunlig

  12. In-line acid concentration measuring method and measuring probe

    Energy Technology Data Exchange (ETDEWEB)

    Kuno, Takehiko; Kurosawa, Akira; Sato, Soichi


    A measuring probe comprising an electrode for voltammetry, a supersonic sensor and a conductivity measuring electrode formed integrally is immersed in a solution for a reprocessing step. A relationship between an acid concentration of the solution having U and Pu concentrations as variable parameters and a propagation speed of supersonic waves in the solution is previously determined, and a propagation speed of the supersonic waves in the solution for the reprocessing step is measured. An acid concentration is determined by using U and Pu concentrations of the solution of the reprocessing step measured in-line by using voltammetry based on the relationship between the acid concentration at that U and Pu concentrations and the supersonic propagation speed. In addition, conductivity of the liquid for the step is measured by a solution conductivity meter, and an acid concentration is measured in-line based on the relationship between the acid concentration and the conductivity in the same manner. With such procedures, a reprocessing plant can be operated rapidly and smoothly, as well as the analysis operation can be simplified. (T.M.)

  13. Concentration Polarization in Translocation of DNA through Nanopores and Nanochannels

    NARCIS (Netherlands)

    Das, Siddhartha; Dubsky, Pavel; Berg, van den Albert; Eijkel, J.C.T.


    In this Letter we provide a theory to show that high-field electrokinetic translocation of DNA through nanopores or nanochannels causes large transient variations of the ionic concentrations in front and at the back of the DNA due to concentration polarization (CP). The CP causes strong local conduc

  14. Raltegravir cerebrospinal fluid concentrations in HIV-1 infection.

    Directory of Open Access Journals (Sweden)

    Aylin Yilmaz

    Full Text Available INTRODUCTION: Raltegravir is an HIV-1 integrase inhibitor currently used in treatment-experienced HIV-1-infected patients resistant to other drug classes. In order to assess its central nervous system penetration, we measured raltegravir concentrations in cerebrospinal fluid (CSF and plasma in subjects receiving antiretroviral treatment regimens containing this drug. METHODS: Raltegravir concentrations were determined by liquid chromatography tandem mass spectrometry in 25 paired CSF and plasma samples from 16 HIV-1-infected individuals. The lower limit of quantitation was 2.0 ng/ml for CSF and 10 ng/ml for plasma. RESULTS: Twenty-four of the 25 CSF samples had detectable raltegravir concentrations with a median raltegravir concentration of 18.4 ng/ml (range, <2.0-126.0. The median plasma raltegravir concentration was 448 ng/ml (range, 37-5180. CSF raltegravir concentrations correlated with CSF:plasma albumin ratios and CSF albumin concentrations. CONCLUSIONS: Approximately 50% of the CSF specimens exceeded the IC(95 levels reported to inhibit HIV-1 strains without resistance to integrase inhibitors. In addition to contributing to control of systemic HIV-1 infection, raltegravir achieves local inhibitory concentrations in CSF in most, but not all, patients. Blood-brain and blood-CSF barriers likely restrict drug entry, while enhanced permeability of these barriers enhances drug entry.

  15. An Automatic High Efficient Method for Dish Concentrator Alignment

    Directory of Open Access Journals (Sweden)

    Yong Wang


    for the alignment of faceted solar dish concentrator. The isosceles triangle configuration of facet’s footholds determines a fixed relation between light spot displacements and foothold movements, which allows an automatic determination of the amount of adjustments. Tests on a 25 kW Stirling Energy System dish concentrator verify the feasibility, accuracy, and efficiency of our method.

  16. Urine and serum concentrations of inhaled and oral terbutaline

    DEFF Research Database (Denmark)

    Elers, Jimmi; Hostrup, Morten; Pedersen, Lars


    We examined urine and serum concentrations after therapeutic use of single and repetitive doses of inhaled and supratherapeutic oral use of terbutaline. We compared the concentrations in 10 asthmatics and 10 healthy subjects in an open-label, cross-over study with 2 mg inhaled and 10 mg oral terb...... therapeutic and prohibited use based on doping tests with urine and blood samples....

  17. Blood and urinary concentrations of salbutamol in asthmatic subjects

    DEFF Research Database (Denmark)

    Elers, Jimmi; Pedersen, Lars; Henninge, John;


    Data on blood and urinary concentrations of salbutamol after inhalation and oral administration in healthy subjects are scarce. Accordingly, we examined the pharmacokinetics of inhaled and oral salbutamol in asthmatic subjects.......Data on blood and urinary concentrations of salbutamol after inhalation and oral administration in healthy subjects are scarce. Accordingly, we examined the pharmacokinetics of inhaled and oral salbutamol in asthmatic subjects....

  18. Modeling the Factors Impacting Pesticide Concentrations in Groundwater Wells. (United States)

    Aisopou, Angeliki; Binning, Philip J; Albrechtsen, Hans-Jørgen; Bjerg, Poul L


    This study examines the effect of pumping, hydrogeology, and pesticide characteristics on pesticide concentrations in production wells using a reactive transport model in two conceptual hydrogeologic systems; a layered aquifer with and without a stream present. The pumping rate can significantly affect the pesticide breakthrough time and maximum concentration at the well. The effect of the pumping rate on the pesticide concentration depends on the hydrogeology of the aquifer; in a layered aquifer, a high pumping rate resulted in a considerably different breakthrough than a low pumping rate, while in an aquifer with a stream the effect of the pumping rate was insignificant. Pesticide application history and properties have also a great impact on the effect of the pumping rate on the concentration at the well. The findings of the study show that variable pumping rates can generate temporal variability in the concentration at the well, which helps understanding the results of groundwater monitoring programs. The results are used to provide guidance on the design of pumping and regulatory changes for the long-term supply of safe groundwater. The fate of selected pesticides is examined, for example, if the application of bentazone in a region with a layered aquifer stops today, the concentration at the well can continue to increase for 20 years if a low pumping rate is applied. This study concludes that because of the rapid response of the pesticide concentration at the drinking water well due to changes in pumping, wellhead management is important for managing pesticide concentrations.

  19. Concentrations, cumulative exposure and critical levels of ozone in Ireland

    NARCIS (Netherlands)

    Kluizenaar, Y. de; Aherne, J.; Farrell, E.P.


    Concentrations of tropospheric ozone (O3) and exceedance of critical levels to vegetation have been investigated and mapped for Ireland. Hourly ozone concentration data (1995–1997) at 7 seven monitoring stations and the CORINE landcover database, supported by a Geographical Information System, were

  20. 10000 Tonnes Of Copper Concentrate Arrived At Nanjing Port

    Institute of Scientific and Technical Information of China (English)


    On March 20,a cargo ship loaded with 10000tonnes of copper concentrate docked at Nanjing Port,signaling that the biggest overseas acquisition project of China’s metal industry received concrete result.On that day,the first batch shipment of 11330tonnes of copper concentrate from Peru Las Bambas Copper Mine,a project jointly

  1. Concentration Fluctuations in Smoke Plumes Released Near the Ground

    DEFF Research Database (Denmark)

    Ejsing Jørgensen, Hans; Mikkelsen, Torben; Pécseli, H.L.


    results are tested against these hypotheses. We find strong evidence for a simple scaling of the standard deviation, skewness and kurtosis with the average concentrations at the downwind distances observed in our experiments. Near-ground concentration fluctuations in fixed as well as moving frames...

  2. 40 CFR 761.274 - Reporting PCB concentrations in samples. (United States)


    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Reporting PCB concentrations in... COMMERCE, AND USE PROHIBITIONS Cleanup Site Characterization Sampling for PCB Remediation Waste in Accordance with § 761.61(a)(2) § 761.274 Reporting PCB concentrations in samples. (a) Report all...

  3. China Sets the Standards for Copper Concentrates Import

    Institute of Scientific and Technical Information of China (English)


    <正>In order to safeguard the people’s health and the environment as well as the State interests, China’s related government authorities recently released a notice limiting the import of copper concentrates containing harmful elements. Based on the regulations, the imported copper concentrates (Code No. 2603000010 and 2603000090) will not be allowed to enter into

  4. Respiratory ammonia output and blood ammonia concentration during incremental exercise

    NARCIS (Netherlands)

    Ament, W; Huizenga, [No Value; Kort, E; van der Mark, TW; Grevink, RG; Verkerke, GJ


    The aim of this study was to investigate whether the increase of ammonia concentration and lactate concentration in blood was accompanied by an increased expiration of ammonia during graded exercise. Eleven healthy subjects performed an incremental cycle ergometer test. Blood ammonia, blood lactate

  5. Perihelion Concentration of Comets; III, Physics and Astrophysics

    CERN Document Server

    Klacka, J


    The problem of concentration of cometary perihelia on the sphere is discussed from the point of view of physics and astronomy. The important facts which may be crucial in understanding the observed concentration of cometary perihelia in the direction of solar apex are presented.

  6. Modelling anaerobic biomass growth kinetics with a substrate threshold concentration

    NARCIS (Netherlands)

    Ribes, J.; Keesman, K.J.; Spanjers, H.


    Abstract Many bacteria have been observed to stop growing below a certain substrate threshold concentration. In this study, a modification of the Monod kinetics expression has been proposed to take into account this substrate threshold concentration observed in bacterial growth. Besides the threshol

  7. Numerical Study of Concentration Characteristics of Linear Fresnel Reflector System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Jin [Kookmin Univ., Seoul (Korea, Republic of); Kim, Jong Kyu; Lee, Sang Nam [Korea Institute of Energy Research, Daejeon (Korea, Republic of)


    In this study, we numerically investigated the concentration characteristics of a linear Fresnel reflector system that can drive a solar thermal absorption refrigeration system to be installed in Saudi Arabia. Using an optical modeling program based on the Monte Carlo ray-tracing method, we simulated the concentrated solar flux, concentration efficiency, and concentrated solar energy on four representative days of the year - the vernal equinox, summer solstice, autumnal equinox, and winter solstice. Except the winter solstice, the concentrations were approximately steady from 9 AM to 15 PM, and the concentration efficiencies exceed 70%. Moreover, the maximum solar flux around the solar receiver center changes only within the range of 13.0 - 14.6 kW/m{sup 2}. When we investigated the effects of the receiver installation height, reflector width, and reflector gap, the optimal receiver installation height was found to be 5 m. A smaller reflector width had a greater concentration efficiency. However, the design of the reflector width should be based on the capacity of the refrigeration system because it dominantly affects the concentrated solar energy. The present study was an essential prerequisite for thermal analyses of the solar receiver. Thus, an optical-thermal integration study in the future will assist with the performance prediction and design of the entire system.

  8. Mercury concentrations of bluegill (Lepomis macrochirus) vary by sex (United States)

    Madenjian, Charles P.; Francis, James T.; Braunscheidel, Jeffrey J.; Bohr, Joseph R.; Geiger, Matthew J.; Knottnerus, G. Mark


    Patterns in relative differences in contaminant concentrations between the sexes across many species of fish may reveal clues for important behavioral and physiological differences between the sexes, and may also be useful in developing fish consumption advisories and efficient designs for programs meant to monitor contaminant levels in fish. We determined skin-off fillet and whole-fish total mercury (Hg) concentrations of 28 adult female and 26 adult male bluegills (Lepomis macrochirus) from Squaw Lake, Oakland County, Michigan (MI), USA. Bioenergetics modeling was used to quantify the effect of growth dilution on the difference in Hg concentrations between the sexes. On average, skin-off fillet and whole-fish Hg concentrations were 25.4% higher and 26.6% higher, respectively, in females compared with males. Thus, the relative difference in Hg concentrations between the sexes for skin-off fillets was nearly identical to that for whole fish. However, mean skin-off fillet Hg concentration (363 ng/g) was 2.3 times greater than mean whole-fish Hg concentration (155 ng/g). Males grew substantially faster than females, and bioenergetics modeling results indicated that the growth dilution effect could account for females having 14.4% higher Hg concentrations than males. Our findings should be useful in revising fish consumption advisories.

  9. Long-term optical stability of fluorescent solar concentrator plates

    NARCIS (Netherlands)

    Slooff, Lenneke H.; Bakker, Nicolaas J.; Sommeling, Paul M.; Büchtemann, Andreas; Wedel, Armin; Van Sark, Wilfried G J H M


    Fluorescent solar concentrators offer an alternative approach for low-cost photovoltaic energy conversion. For successful application, not only the power conversion efficiency and cost are important, but also lifetime or stability of the devices. As today's concentrator is made of polymer sheets con

  10. Calculation of the debris flow concentration based on clay content

    Institute of Scientific and Technical Information of China (English)

    CHEN Ningsheng; CUI Peng; LIU Zhonggang; WEI Fangqiang


    The debris flow clay content has very tremendous influence on its concentration (γC). It is reported that the concentration can be calculated by applying the relative polynomial based on the clay content. Here one polynomial model and one logarithm model to calculate the concentration based on the clay content for both the ordinary debris flow and viscous debris flow are obtained. The result derives from the statistics and analysis of the relationship between the debris flow concentrations and clay content in 45 debris flow sites located in the southwest of China. The models can be applied for the concentration calculation to those debris flows that are impossible to observe. The models are available to calculate the debris flow concentration, the principles of which are in the clay content affecting on the debris flow formation, movement and suspending particle diameter. The mechanism of the relationship of the clay content and concentration is clear and reliable. The debris flow is usually of micro-viscous when the clay content is low (<3%), by analyzing the developing tendency on the basics of the relationship between the clay content and debris flow concentration. Indeed, the less the clay content, the less the concentration for most debris flows. The debris flow tends to become the water rock flow or the hyperconcentrated flow with the clay content decrease. Through statistics it is apt to transform the soil into the viscous debris flow when the clay content of ranges is in 3%-18%. Its concentration increases with the increasing of the clay content when the clay content is between 5% and 10%. But the value decreases with the increasing of the clay content when the clay content is between 10% and 18%. It is apt to transform the soil into the mudflow, when the clay content exceeds 18%. The concentration of the mudflow usually decreases with the increase of the clay content, and this developing tendency reverses to that of the micro-viscous debris flow. There is

  11. Histopathological changes in relation to cadmium concentration in horse kidneys

    Energy Technology Data Exchange (ETDEWEB)

    Elinder, C.G.; Jonsson, L.; Piscator, M.; Rahnster, B.


    Histopathological changes in kidney cortex, as observed by light microscopy, are related to cadmium concentration in kidney cortex from 69 normal Swedish horses. Cadmium concentrations in kidney ranged from 11 to 186 Cd/g wet wt with an average of 60 Cd/g, which is considerably higher than those normally found in humans. The microscopical changes were rated and related to cadmium concentrations in kidneys by dose-response curves. A relationship existed between frequency of morphological changes and cadmium concentration in the renal cortex. There was no obvious relationship between age and frequency of histopathological changes. This indicates that in horse kidneys morphological changes occur at cadmium concentrations which are lower than the tentative critical level for humans of 200 Cd/g. It is concluded that horses constitute a population at risk for environmental cadmium contamination.

  12. Photovoltaic concentrator module reliability: Failure modes and qualification

    Energy Technology Data Exchange (ETDEWEB)

    Richards, E.H.


    The purpose of this paper is to discuss the current issues of interest in PV concentrator module reliability. Before describing in detail the reliability concerns about PV concentrator modules, it should be emphasized that, with proper design and attention to quality control, there is nothing to prevent concentrator modules from being as reliable as crystalline-silicon flat-plate modules have proven to be. Concentrator modules tested outdoors, as well as in the first-generation systems, have generally been reliable, and no degradation in cell output has been observed. Also, although they are not included in this paper, there are a few items currently of concern with the reliability of other PV module technologies that are not issues with PV concentrator technology, such as the stability of amorphous-silicon efficiencies and concerns about EVA encapsulation.

  13. Particle size- and concentration-dependent separation of magnetic nanoparticles (United States)

    Witte, Kerstin; Müller, Knut; Grüttner, Cordula; Westphal, Fritz; Johansson, Christer


    Small magnetic nanoparticles with a narrow size distribution are of great interest for several biomedical applications. When the size of the particles decreases, the magnetic moment of the particles decreases. This leads to a significant increase in the separation time by several orders of magnitude. Therefore, in the present study the separation processes of bionized nanoferrites (BNF) with different sizes and concentrations were investigated with the commercial Sepmag Q system. It was found that an increasing initial particle concentration leads to a reduction of the separation time for large nanoparticles due to the higher probability of building chains. Small nanoparticles showed exactly the opposite behavior with rising particle concentration up to 0.1 mg(Fe)/ml. For higher iron concentrations the separation time remains constant and the measured Z-average decreases in the supernatant at same time intervals. At half separation time a high yield with decreasing hydrodynamic diameter of particles can be obtained using higher initial particle concentrations.

  14. Concentration in Knowledge Output: A case of Economics Journals

    Directory of Open Access Journals (Sweden)

    Paul Gopuran Devassy Bino


    Full Text Available This paper assesses the degree of author concentration in seven economics journals, which were published in India during 1990-2002. To measure the degree of author concentration, Lotka's Law was used. Moreover, we also make an exploratory analysis of the geographic, economics subfield and institutional concentration in 704 economics journals. An important finding of this paper is that specialized journals in the sample report the highest degree of author concentration. This result is quite similar to the findings by Cox and Chung (1991. Furthermore, there are several instances showing that the journals lean towards certain norms; this may affect the flow of innovative ideas into economics. We conclude that a knowledge activity, involving the high degree of concentration and a biased publication process, may affect the flow of new ideas into the discipline.


    Nakagawa, Kei; Tsuzuki, Megumi; Asakura, Hiroshi

    It seems important to examine heavy metal concentration in playgrounds, to evaluate potential risk for heavy metal ingestion by children. In this study, heavy metal concentrations of soil samples in 40 playgrounds in K-city were investigated by the voltammetric method. To visualize heavy metal concentration distribution in playgrounds, free GIS software MANDARA was used. According to the comparison between the 1 N HCl dissolved concentration and the PTWI (Provisional Tolerable Weekly Intake), playgrounds in K-city may not have intake risk of lead. Even if the possibility of the risk was very low, there are differences of the intensities. As for the specific playground where concentration is high, investigating continuously may be desirable hereafter.

  16. Update of the Solar Concentrator Advanced Development Project (United States)

    Corrigan, Robert D.; Peterson, Todd T.; Ehresman, Derik T.


    The Solar Concentrator Advanced Development Project, which has achieved the successful design, fabrication, and testing of a full-scale prototypical solar dynamic concentrator, is discussed. The design and fabrication process are summarized, and the test results for the reflective facet optical performance and the concentrator structural repeatability are reported. Initial testing of structural repeatability of a seven panel portion of the concentrator was followed by assembly and testing of the full nineteen-panel structure. The testing, which consisted of theodolite and optical measurements over an assembly-disassembly-reassembly cycle, demonstrated that the concentrator maintained the as-built contour and optical characteristics. The facet development effort, which entailed developing a vapor-deposited reflective facet, produced a viable design with demonstrated optical characteristics that are within the project goals.

  17. Model for Predicting Roadside Concentrations of Traffic Pollutants

    Institute of Scientific and Technical Information of China (English)

    YANG Zhongzhen; MIAO Guoqiang; WANG Lu


    An analytical model is presented to estimate traffic pollutant concentrations based on an artificial neural network (ANN) approach. The model can analyze the highly nonlinear relationship between the traffic flow attributes, meteorological conditions, road spatial characteristics, and the traffic pollutant concentrations.This study analyzes the multiple factors that affect the pollutant concentration and establishes the model structure using the ANN technique. Collected data for the pollutant concentrations as functions of variant factors was used to train the ANN model. A method was developed to automatically measure the traffic flow attributes, such as traffic flow, vehicle speed, and flow composition from video data. The results indicate that the model can reliably forecast CO2 concentrations along the roads.

  18. The Flow Behavior of Poly(m-Phenyleneisophthalamide) Concentrated Solution

    Institute of Scientific and Technical Information of China (English)


    By means of HAAKE RS105L cone and plate rheometer theflow behavior of poly (m-phenyleneisophthalamide ) (PMIA)concentrated solution, including viscous flow activation energy, non-Newtonian index, structural viscosity index and relaxation time of the PMIA solution were studied. The effect of concentration and temperature of the solution and molecular weight of the polymer on its non-Newtonian behavior was investigated. The results showed that PMIA concentrated solutien prepared via low temperature condensation was of non-Newtonian fluid. With the decrease of trmperature,increase of solution concentration and PMIA molecular weight, the deviation of the solution from Newtonian behavior decreased. The molecular weight of the polymer and the concentration of the solution affected the nonNewtonian behavior more intensively.

  19. Ergodic to non-ergodic transition in low concentration Laponite

    Energy Technology Data Exchange (ETDEWEB)

    Ruzicka, B; Zulian, L; Ruocco, G [INFM and Dipartimento di Fisica, Universita di Roma ' La Sapienza' , I-00185 Rome (Italy)


    At variance with previous determinations, recent investigations on water suspension of a synthetic clay (Laponite) have shown the presence of an arrested phase also at very low clay concentrations (down to C{sub w} = 0.003). This surprising behaviour has been studied in a wide clay concentration range. As a result the existence of two different routes towards the arrested phase, applying to low and high Laponite concentrations, has been found. We can speculate that at high clay concentration the system would form a Wigner glass whose elementary units are single Laponite platelets, as already indicated in previous works. At low clay concentrations, in contrast, the Wigner glass is supposed to be composed of clusters of Laponite platelets; in this case the clusters would be stabilized by the competition of long-range electrostatic repulsion and short-range attractive interactions. A similar behaviour has been recently found in a simulation work (Sciortino et al 2003 Preprint cond-mat/0312161)

  20. Optimization of Secondary Concentrators with the Continuous Information Entropy Strategy (United States)

    Schmidt, Tobias Christian; Ries, Harald


    In this contribution, a method for global optimization of noisy functions, the Continuous Information Entropy Strategy (CIES), is explained and its applicability for the optimization of solar concentrators is shown. The CIES is efficient because all decisions made during optimizations are based on criteria that are derived from the concept of information entropy. Two secondary concentrators have been optimized with the CIES. The optimized secondary concentrators convert circular light distributions of round focal spots to square light distributions to match with the shape of square PV cells. The secondary concentrators are highly efficient and have geometrical concentration ratios of 2.25 and 8 respectively. Part of this material has been published in: T. C. Schmidt, "Information Entropy-Based Decision Making in Optimization", Ph.D. Thesis, Philipps University Marburg, 2010.

  1. Long-memory property in air pollutant concentrations (United States)

    Chelani, Asha


    In the present paper, long-memory in air pollutant concentrations is reviewed and outcome of the past studies is analyzed to provide the possible mechanism behind temporal evolution of air pollutant concentrations. It is observed that almost all the studies show air pollutant concentrations over time possess persistence up to a certain limit. Self-organized criticality of air pollution, multiplicative process of pollutant concentrations, and uniformity in emission sources leading to self-organized criticality are few of the phenomena behind the persistent property of air pollutant concentrations. The self-organized criticality of air pollution is linked to atmosphere's self-cleansing mechanism. This demonstrates that inspite of increasing anthropogenic emissions, self-organized criticality of air pollution is sustained and has low influence of human interventions. In the future, this property may, however, be perturbed due to continuous air pollution emissions, which may influence the accuracy in predictions.


    Institute of Scientific and Technical Information of China (English)

    Guangqian WANG; Xudong FU


    In steady, solid-liquid two-phase turbulent flows, there exist two typical patterns of the vertical distribution of particle concentration. The pattern I shows a maximum concentration at an elevation above the bed. The pattern II shows an increase of the particle concentration downward over the whole vertical,with the maximum at the bed. Most of the theories on particle concentration distribution have been done with the pattern II, and it is lack of a successful theory coveting both of the two patterns. This paper reviews the particle distribution theories, including the diffusion theory, the mixture theory, the energy theory, the similarity theory, the stochastic theory and the kinetic theory. The kinetic theory is also applied to describe the vertical distribution of particle concentration in both dilute and dense flows.

  3. Barrier, mechanical and optical properties of whey protein concentrate films

    Directory of Open Access Journals (Sweden)

    Viviane Machado Azevedo


    Full Text Available Whey is recognized as a valuable source of high quality protein and, when processed as protein concentrate, may be used in the production of biodegradable films. The objective of the study was to develop films of whey protein concentrate 80% (WPC at concentrations of 6, 8, 10 and 12% and evaluate the influence of this factor in the barrier, mechanical and optical properties of the films. Treatments showed moisture content with a mean value of 22.10% ± 0.76and high solubility values between 56.67 to 62.42%. Thus, there is little or no influence of varying the concentration of WPC in these properties and high hydrophilicity of the films. With increasing concentration of WPC, increases the water vapor permeability of the films (7.42 x 10-13 to 3.49 x 10-12 g.m-1.s-1.Pa-1. The treatment at the concentration of 6% of WPC showed a higher modulus of elasticity (287.90 ± 41.79 MPa. Thegreater rigidity in films with higher concentrations is possibly due to the greater number of bonds between molecules of the polymeric matrix. The films have the same puncture resistance. The increased concentration of WPC promotes resistance to the action of a localized force. In general, films of whey protein concentrate in the tested concentrations exhibited slightly yellowish color and transparency, and can be used in food packaging that requiring intermediate permeability to water vapor, to keep moisture and texture desired.

  4. Riparian zone controls on base cation concentrations in boreal streams

    Directory of Open Access Journals (Sweden)

    J. L. J. Ledesma


    Full Text Available Forest riparian zones are a major in control of surface water quality. Base cation (BC concentrations, fluxes, and cycling in the riparian zone merit attention because of increasing concern of negative consequences for re-acidification of surface waters from future climate and forest harvesting scenarios. We present a two-year study of BC and silica (Si flow-weighted concentrations from 13 riparian zones and 14 streams in a boreal catchment in northern Sweden. The Riparian Flow-Concentration Integration Model (RIM was used to estimate riparian zone flow-weighted concentrations and tested to predict the stream flow-weighted concentrations. Spatial variation in BC and Si concentrations as well as in flow-weighted concentrations was related to differences in Quaternary deposits, with the largest contribution from lower lying silty sediments and the lowest contribution from wetland areas higher up in the catchment. Temporal stability in the concentrations of most elements, a remarkably stable Mg / Ca ratio in the soil water and a homogeneous mineralogy suggest that the stable patterns found in the riparian zones are a result of distinct mineralogical upslope groundwater signals integrating the chemical signals of biological and chemical weathering. Stream water Mg / Ca ratio indicates that the signal is subsequently maintained in the streams. RIM gave good predictions of Ca, Mg, and Na flow-weighted concentrations in headwater streams. The difficulty in modelling K and Si suggests a stronger biogeochemical influence on these elements. The observed chemical dilution effect with flow in the streams was related to variation in groundwater levels and element concentration profiles in the riparian zones. This study provides a first step toward specific investigations of the vulnerability of riparian zones to changes induced by forest management or climate change, with focus on BC or other compounds.

  5. Riparian zone control on base cation concentration in boreal streams

    Directory of Open Access Journals (Sweden)

    J. L. J. Ledesma


    Full Text Available Riparian zones (RZ are a major factor controlling water chemistry in forest streams. Base cations' (BC concentrations, fluxes, and cycling in the RZ merit attention because a changing climate and increased forest harvesting could have negative consequences, including re-acidification, for boreal surface waters. We present a two-year study of BC and silica (Si flow-weighted concentrations from 13 RZ and 14 streams in different landscape elements of a boreal catchment in northern Sweden. The spatial variation in BC and Si dynamics in both RZ and streams was explained by differences in landscape element type, with highest concentrations in silty sediments and lowest concentrations in peat-dominated wetland areas. Temporal stability in BC and Si concentrations in riparian soil water, remarkably stable Mg/Ca ratios, and homogeneous mineralogy suggest that patterns found in the RZ are a result of a distinct mineralogical upslope signal in groundwater. Stream water Mg/Ca ratios indicate that the signal is subsequently maintained in the streams. Flow-weighted concentrations of Ca, Mg, and Na in headwater streams were represented by the corresponding concentrations in the RZ, which were estimated using the Riparian Flow-Concentration Integration Model (RIM approach. Stream and RZ flow-weighted concentrations differed for K and Si, suggesting a stronger biogeochemical influence on these elements, including K recirculation by vegetation and retention of Si within the RZ. Potential increases in groundwater levels linked to forest harvesting or changes in precipitation regimes would tend to reduce BC concentrations from RZ to streams, potentially leading to episodic acidification.

  6. Starch source in high concentrate rations does not affect rumen pH, histamine and lipopolysaccharide concentrations in dairy cows

    NARCIS (Netherlands)

    Pilachai, R.; Schonewille, J.T.; Thamrongyoswittayakul, C.; Aiumlamai, S.; Wachirapakom, C.; Everts, H.; Hendriks, W.H.


    The replacement of ground corn by cassava meal on rumen pH, lipopolysaccharide (LPS) and histamine concentrations under typical Thai feeding conditions (high concentrate diets and rice straw as the sole source of roughage) was investigated. Four rumen-fistulated crossbred Holstein, non-pregnant, dry

  7. Butanol production from concentrated lactose/whey permeate: Use of pervaporation membrane to recover and concentrate product (United States)

    In these studies butanol (acetone butanol ethanol, or ABE) was produced from concentrated lactose/whey permeate containing 211 gL-1 lactose. Fermentation of such a highly concentrated lactose solution was possible due to simultaneous product removal using a pervaporation membrane. In this system a p...

  8. Breaker concentrations required to improve the permeability of proppant packs damaged by concentrated linear and borate-crosslinked fracturing fluids

    Energy Technology Data Exchange (ETDEWEB)

    Brannon, H. (BJ Services (United States)); Pulsinelli, R.J. (Dowell Schlumberger, Tulsa, OK (United States))


    This paper reports on the concentrations of an oxidative breaker required to reduce significantly the proppant-pack permeability damage caused by aqueous hydraulic fracturing fluids. Long-term, proppant-pack permeability testing was used to evaluate linear and borate-crosslinked gels. Results indicate that increasing the breaker concentration can reduce proppant-pack permeability damage very effectively.

  9. Influence of Bleaching on Flavor of 34% Whey Protein Concentrate and Residual Benzoic Acid Concentration in Dried Whey Proteins (United States)

    Previous studies have shown that bleaching negatively affects the flavor of 70% whey protein concentrate (WPC70), but bleaching effects on lower-protein products have not been established. Benzoyl peroxide (BP), a whey bleaching agent, degrades to benzoic acid (BA) and may elevate BA concentrations...

  10. Influence of bleaching on flavor of 34% whey protein concentrate and residual benzoic acid concentration in dried whey products (United States)

    Previous studies have shown that bleaching negatively affects the flavor of 70% whey protein concentrate (WPC70), but bleaching effects on lower-protein products have not been established. Benzoyl peroxide (BP), a whey bleaching agent, degrades to benzoic acid (BA) and may elevate BA concentrations...

  11. Diagnostic system for measuring temperature, pressure, CO2 concentration and H2O concentration in a fluid stream

    Energy Technology Data Exchange (ETDEWEB)

    Partridge, Jr., William P.; Jatana, Gurneesh Singh; Yoo, Ji-Hyung; Parks, II, James E.


    A diagnostic system for measuring temperature, pressure, CO.sub.2 concentration and H.sub.2O concentration in a fluid stream is described. The system may include one or more probes that sample the fluid stream spatially, temporally and over ranges of pressure and temperature. Laser light sources are directed down pitch optical cables, through a lens and to a mirror, where the light sources are reflected back, through the lens to catch optical cables. The light travels through the catch optical cables to detectors, which provide electrical signals to a processer. The processer utilizes the signals to calculate CO.sub.2 concentration based on the temperatures derived from H.sub.2O vapor concentration. A probe for sampling CO.sub.2 and H.sub.2O vapor concentrations is also disclosed. Various mechanical features interact together to ensure the pitch and catch optical cables are properly aligned with the lens during assembly and use.

  12. Estimation of the indoor radon concentration by the analysis of relationship between the radon concentration and the meteorological parameters

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. H. [Kyunghee Univ., Yongin (Korea, Republic of); Lee, W. K.; Jang, S. Y. [KAERI, Taejon (Korea, Republic of)


    Theoretical equation to estimate the indoor radon concentration can be derived from the multi-regression analysis method for the relationship between the indoor radon concentration and the meteorological variables such as the temperature, pressure and pressure difference at same indoor. The result of multi-regression analysis showed that the indoor radon concentration has been mostly influenced by the variation of the indoor temperature, while not so much influence by the indoor pressure difference. The indoor radon concentration theoretically estimated in this study agreed well with that really measured at same indoor within the range of statistical error. Therefore, it is possible to estimate the indoor rabon concentration by using the theoretical equation adopting the temperature and pressure difference at the same indoor.

  13. Scientific substantination of maximum allowable concentration of fluopicolide in water

    Directory of Open Access Journals (Sweden)

    Pelo I.М.


    Full Text Available In order to substantiate fluopicolide maximum allowable concentration in the water of water reservoirs the research was carried out. Methods of study: laboratory hygienic experiment using organoleptic and sanitary-chemical, sanitary-toxicological, sanitary-microbiological and mathematical methods. The results of fluopicolide influence on organoleptic properties of water, sanitary regimen of reservoirs for household purposes were given and its subthreshold concentration in water by sanitary and toxicological hazard index was calculated. The threshold concentration of the substance by the main hazard criteria was established, the maximum allowable concentration in water was substantiated. The studies led to the following conclusions: fluopicolide threshold concentration in water by organoleptic hazard index (limiting criterion – the smell – 0.15 mg/dm3, general sanitary hazard index (limiting criteria – impact on the number of saprophytic microflora, biochemical oxygen demand and nitrification – 0.015 mg/dm3, the maximum noneffective concentration – 0.14 mg/dm3, the maximum allowable concentration - 0.015 mg/dm3.

  14. Concentration polarization of atherogenic lipids in the arterial system

    Institute of Scientific and Technical Information of China (English)

    DENG; Xiaoyan; (邓小燕); WANG; Guixue; (王贵学)


    The transport of atherogenic lipids (LDL) in a straight segment of an artery with a semi-permeable wall was simulated numerically. The numerical analysis predicted that a mass transport phenomenon called 'concentration polarization' of LDL might occur in the arterial system. Under normal physiological flow conditions, the luminal surface LDL concentration was 5%-14% greater than the bulk concentration in a straight segment of an artery. The luminal surface LDL concentration at the arterial wall was flow-dependent, varying linearly with the filtration rate across the arterial wall and inversely with wall shear rate. At low wall shear rate, the luminal surface LDL concentration was very sensitive to changes in flow conditions, decreasing sharply as wall shear rate increased. In order to verify the numerical analysis, the luminal surface concentration of bovine serum albumin (as a tracer macromolecule) in the canine carotid artery was measured in vitro by directly taking liquid samples from the luminal surface of the artery. The experimental result was in very good agreement with the numerical analysis. The authors believe that the mass transport phenomenon of 'concentration polarization' may indeed exist in the human circulation and play an important role in the localization of atherosclerosis.

  15. Radon concentrations in drinking water in Wakasa area, Fukui Prefecture

    Energy Technology Data Exchange (ETDEWEB)

    Tokuyama, Hideki; Igarashi, Shuichi [Fukui Prefectural Environmental Radiation Research and Monitoring Center, Tsuruga (Japan)


    Radon concentration in drinking water was surveyed to make basic data for the investigation of radiation dose due to natural radioisotopes in the general public. Here, the survey data in the Wakasa region were reported. Sampling was carried out at 126 points in this region (ca. 70x50 km{sup 2}). A total of 167 samples were taken from the tap of private wells, and small and large public water supplies. The radon concentration was determined by direct measuring method. The mean concentration of ground water from the wells was 28.5 Bq/l, significantly higher than those of the tap water from small and large water supplies, 5.0 and 11.2 Bq/l, respectively. Rn concentration of ground water was dependent on geological features and it was comparatively high in the granite region. Ground water containing a high concentration of Rn was mixed into the water of some large water supply in the cities, showing that its Rn concentration was higher compared to those for the small water supply. This survey was conducted only in the winter seasons from 1989 to 1993. Therefore, there are no data concerning seasonal changes in Rn concentration to drinking water. (M.N.)

  16. Phenylketonuria: brain phenylalanine concentrations relate inversely to cerebral protein synthesis. (United States)

    de Groot, Martijn J; Sijens, Paul E; Reijngoud, Dirk-Jan; Paans, Anne M; van Spronsen, Francjan J


    In phenylketonuria, elevated plasma phenylalanine concentrations may disturb blood-to-brain large neutral amino acid (LNAA) transport and cerebral protein synthesis (CPS). We investigated the associations between these processes, using data obtained by positron emission tomography with l-[1-(11)C]-tyrosine ((11)C-Tyr) as a tracer. Blood-to-brain transport of non-Phe LNAAs was modeled by the rate constant for (11)C-Tyr transport from arterial plasma to brain tissue (K1), while CPS was modeled by the rate constant for (11)C-Tyr incorporation into cerebral protein (k3). Brain phenylalanine concentrations were measured by magnetic resonance spectroscopy in three volumes of interest (VOIs): supraventricular brain tissue (VOI 1), ventricular brain tissue (VOI 2), and fluid-containing ventricular voxels (VOI 3). The associations between k3 and each predictor variable were analyzed by multiple linear regression. The rate constant k3 was inversely associated with brain phenylalanine concentrations in VOIs 2 and 3 (adjusted R(2)=0.826, F=19.936, P=0.021). Since brain phenylalanine concentrations in these VOIs highly correlated with each other, the specific associations of each predictor with k3 could not be determined. The associations between k3 and plasma phenylalanine concentration, K1, and brain phenylalanine concentrations in VOI 1 were nonsignificant. In conclusion, our study shows an inverse association between k3 and increased brain phenylalanine concentrations.

  17. Experimental study of chemical concentration variation of ASP flooding

    Institute of Scientific and Technical Information of China (English)


    A physical modeling system of long slim tube was established. Several pressure measuring and sampling points were laid out at different positions along the tube. Through real-time measurements of pressures and chemical concentrations at different points, the mass transfer and chemical concentration of ASP flooding in porous media are studied. The concentration of chemicals declines gradually during the fluid flow from the inlet to the outlet of the model. The concentration increases in the front edge of the slug faster than the concentration decreases in the rear edge of the slug. The concentration variation of the chemicals is an asymmetrical and offset process. The order of motion velocities of the chemicals from fast to slow is polymer, alkali and surfactant. The motion lag and comprehensive diffusion are strong in the vicinity of the inlet, the motion velocities of the chemicals are high, the difference of flow velocities among the three chemicals is significant and the chromatographic separation of the chemicals is obvious. In the area near the outlet, the comprehensive diffusion and motion lag become weak, the concentrations of the chemicals decrease, the motion velocities of the chemicals are slow, the difference among the motion velocities of the chemicals becomes small, the chromatographic separation is not obvious, the adsorption and retention of chemicals gradually increase as the chemical slug moves further along the tube, the adsorption and retention of polymer is the most serious.

  18. High Black Carbon (BC) Concentrations along Indian National Highways (United States)

    Kumar, S.; Singh, A. K.; Singh, R. P.


    Abstract:Black carbon (BC), the optically absorbing component of carbonaceous aerosol, has direct influence on radiation budget and global warming. Vehicular pollution is one of the main sources for poor air quality and also atmospheric pollution. The number of diesel vehicles has increased on the Indian National Highways during day and night; these vehicles are used for the transport of goods from one city to another city and also used for public transport. A smoke plume from the vehicles is a common feature on the highways. We have made measurements of BC mass concentrations along the Indian National Highways using a potable Aethalometer installed in a moving car. We have carried out measurements along Varanasi to Kanpur (NH-2), Varanasi to Durgapur (NH-2), Varanasi to Singrauli (SH-5A) and Varanasi to Ghazipur (NH-29). We have found high concentration of BC along highways, the average BC mass concentrations vary in the range 20 - 40 µg/m3 and found high BC mass concentrations up to 600 μg/m3. Along the highways high BC concentrations were characteristics of the presence of industrial area, power plants, brick kilns and slow or standing vehicles. The effect of increasing BC concentrations along the National Highways and its impact on the vegetation and human health will be presented. Key Words: Black Carbon; Aethalometer; mass concentration; Indian National Highways.

  19. Taurine concentrations in fetal, neonatal and pregnant rats.

    Directory of Open Access Journals (Sweden)



    Full Text Available The concentrations of taurine in the fetal and neonatal organs, and the maternal organs, plasma and urine of rats between the 15th day of gestation and the 21st day after birth were determined using an automatic amino acid analyzer. In the fetal liver and brain and in the placenta, the taurine concentration was the highest of all ninhydrin positive compounds. In the fetal liver and placenta, the concentrations of taurine increased significantly with the gestational days. Concentrations of taurine in the brain were much higher in the fetus and neonate than that in the adult. Moreover, the total amount of taurine per fetus increased markedly after the 15th day of gestation, and near term, reached almost the same amount as in the adult rat liver. In contrast to this, a significant decrease was observed in the taurine concentration in the maternal liver and muscle near term. The concentration of taurine in the urine of pregnant rats decreased near term, but in the plasma of pregnant rats the concentration of taurine did not change during pregnancy.

  20. Background phosphorus concentrations in Danish groundwater and surface water bodies (United States)

    Kronvang, Brian; Bøgestrand, Jens; Windolf, Jørgen; Ovesen, Niels; Troldborg, Lars


    Quantitative information on the background concentration and loading of phosphorus is important when establishing the pressure-impact pathway for Danish streams, lakes and estuaries The background phosphorus loading thus determines present day lowest phosphorus loadings without influence from point sources and agriculture. We have mapped the background concentration of phosphorus in Danish groundwater and streams based on monitoring in 3000 groundwater wells, 7 small streams draining undisturbed catchments (1990-2010) and 19 streams draining small undisturbed catchments being monitored during 2004-2005. The concentration particulate P (PP) was found to be nearly constant within eight major georegions of Denmark (0.018 mg ± 0.010 mg P L-1. On contrary, the concentration of total dissolved P (TDP) was found to vary between 0.011-0.071 mg P L-1 within the eight georegions. We have also time series of background total P concentrations from 7 small undisturbed catchments covering the period 1990-2010. No significant trends have been observed in total P concentrations from these streams during the period 1990-2010. The average annual background loss of total phosphorus amounts to 730 tonnes P or 29% of the total loading of phosphorus from the Danish land to sea during the period 2007-2011. The measured TDP concentration in groundwater was much higher under reduced conditions (median: 0.10-0.15 mg P L-1) than in oxidized groundwater (Journal of Hydrology (280) 52-71.