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Sample records for system algainassb properties

  1. Mass properties measurement system dynamics

    NASA Technical Reports Server (NTRS)

    Doty, Keith L.

    1993-01-01

    The MPMS mechanism possess two revolute degrees-of-freedom and allows the user to measure the mass, center of gravity, and the inertia tensor of an unknown mass. The dynamics of the Mass Properties Measurement System (MPMS) from the Lagrangian approach to illustrate the dependency of the motion on the unknown parameters.

  2. Error analysis of system mass properties

    NASA Technical Reports Server (NTRS)

    Brayshaw, J.

    1984-01-01

    An attempt is made to verify the margin of system mass properties over values that are sufficient for the support of such other critical system requirements as those of dynamic control. System nominal mass properties are designed on the basis of an imperfect understanding of the mass and location of constituent elements; the effect of such element errors is to introduce net errors into calculated system mass properties. The direct measurement of system mass properties is, however, impractical. Attention is given to these issues in the case of the Galileo spacecraft.

  3. Ultrasonic System Measures Elastic Properties Of Composites

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Mal, Ajit K.

    1993-01-01

    Measurements with leaky Lamb waves yield data on properties and defects of panels. System nondestructively measures elastic properties of, and defects in, panel of laminated fiber/matrix material. Ultrasonic transducers operating in pitch/catch mode excite and detect leaky Lamb waves in specimen. Elastic properties of specimen and defects within it characterized from dispersion curves of Lamb waves.

  4. MyPropertyInfo - List of Systems

    EPA Pesticide Factsheets

    2016-02-22

    MyPropertyInfo provides a single, printable report based on individual address searches from numerous EPA databases. MyPropertyInfo's results come from EPA's Facility Registry System which contains information on over 2.6 million facilities or sites of interest to EPA.

  5. Wada property in systems with delay

    NASA Astrophysics Data System (ADS)

    Daza, Alvar; Wagemakers, Alexandre; Sanjuán, Miguel A. F.

    2017-02-01

    Delay differential equations take into account the transmission time of the information. These delayed signals may turn a predictable system into chaotic, with the usual fractalization of the phase space. In this work, we study the connection between delay and unpredictability, in particular we focus on the Wada property in systems with delay. This topological property gives rise to dramatic changes in the final state for small changes in the history functions.

  6. The review-of-particle-properties system

    NASA Astrophysics Data System (ADS)

    Trippe, Thomas G.

    1984-08-01

    The Berkeley Particle Data Group is engaged in a major modernization of its primary project, the Review of Particle Properties, a compilation of experimental data on elementary particles. The goal of this modernization is to develop an integrated system for data storage, manipulation, interactive access and publication using modern techniques for database management, text processing and phototypesetting. The existing system and the plans for modernization are described. The group's other projects and the computer systems used are also discussed.

  7. Quantum optical properties in plasmonic systems

    NASA Astrophysics Data System (ADS)

    Ooi, C. H. Raymond

    2015-04-01

    Plasmonic metallic particle (MP) can affect the optical properties of a quantum system (QS) in a remarkable way. We develop a general quantum nonlinear formalism with exact vectorial description for the scattered photons by the QS. The formalism enables us to study the variations of the dielectric function and photon spectrum of the QS with the particle distance between QS and MP, exciting laser direction, polarization and phase in the presence of surface plasmon resonance (SPR) in the MP. The quantum formalism also serves as a powerful tool for studying the effects of these parameters on the nonclassical properties of the scattered photons. The plasmonic effect of nanoparticles has promising possibilities as it provides a new way for manipulating quantum optical properties of light in nanophotonic systems.

  8. 48 CFR 3045.511 - Audit of property control system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 7 2011-10-01 2011-10-01 false Audit of property control... Government Property in the Possession of Contractors 3045.511 Audit of property control system. (a) The... contractor's property control system whenever there are indications that the contractor's property...

  9. 48 CFR 3045.511 - Audit of property control system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Audit of property control... Government Property in the Possession of Contractors 3045.511 Audit of property control system. (a) The... contractor's property control system whenever there are indications that the contractor's property...

  10. Remediation System Evaluation, Ellis Property Superfund Site

    EPA Pesticide Factsheets

    The Ellis Property Superfund Site is located in a rural area of Burlington County, New Jersey. Most ofthe land at the site has not been developed. However, there is a building in a fenced area that is used tohouse the remedial system..

  11. 10 CFR 600.323 - Property management system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Property management system. 600.323 Section 600.323 Energy....323 Property management system. The recipient's property management system must include the following... existence, current utilization, and continued need for the property. (d) A control system must be in...

  12. 48 CFR 245.105 - Contractors' property management system compliance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... contractor's failure to meet one or more of the property management system criteria in the clause at 252.245... the system criteria for an acceptable property management system as prescribed in the clause at...

  13. 48 CFR 1245.511 - Audit of property control system.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Audit of property control... 1245.511 Audit of property control system. (a) The property administrator (or other Government official authorized by the contracting officer) shall audit the contractor's property control system whenever...

  14. 48 CFR 1245.511 - Audit of property control system.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Audit of property control... 1245.511 Audit of property control system. (a) The property administrator (or other Government official authorized by the contracting officer) shall audit the contractor's property control system whenever...

  15. 48 CFR 1245.511 - Audit of property control system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Audit of property control... 1245.511 Audit of property control system. (a) The property administrator (or other Government official authorized by the contracting officer) shall audit the contractor's property control system whenever...

  16. 48 CFR 1245.511 - Audit of property control system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Audit of property control... 1245.511 Audit of property control system. (a) The property administrator (or other Government official authorized by the contracting officer) shall audit the contractor's property control system whenever...

  17. Properties of on-line social systems

    NASA Astrophysics Data System (ADS)

    Grabowski, A.; Kruszewska, N.; Kosiński, R. A.

    2008-11-01

    We study properties of five different social systems: (i) internet society of friends consisting of over 106 people, (ii) social network consisting of 3 × 104 individuals, who interact in a large virtual world of Massive Multiplayer Online Role Playing Games (MMORPGs), (iii) over 106 users of music community website, (iv) over 5 × 106 users of gamers community server and (v) over 0.25 × 106 users of books admirer website. Individuals included in large social network form an Internet community and organize themselves in groups of different sizes. The destiny of those systems, as well as the method of creating of new connections, are different, however we found that the properties of these networks are very similar. We have found that the network components size distribution follow the power-law scaling form. In all five systems we have found interesting scaling laws concerning human dynamics. Our research has shown how long people are interested in a single task, how much time they devote to it and how fast they are making friends. It is surprising that the time evolution of an individual connectivity is very similar in each system.

  18. Thermoelectric property measurements with computer controlled systems

    NASA Technical Reports Server (NTRS)

    Chmielewski, A. B.; Wood, C.

    1984-01-01

    A joint JPL-NASA program to develop an automated system to measure the thermoelectric properties of newly developed materials is described. Consideration is given to the difficulties created by signal drift in measurements of Hall voltage and the Large Delta T Seebeck coefficient. The benefits of a computerized system were examined with respect to error reduction and time savings for human operators. It is shown that the time required to measure Hall voltage can be reduced by a factor of 10 when a computer is used to fit a curve to the ratio of the measured signal and its standard deviation. The accuracy of measurements of the Large Delta T Seebeck coefficient and thermal diffusivity was also enhanced by the use of computers.

  19. Atmospheric propagation properties of various laser systems

    NASA Astrophysics Data System (ADS)

    Pitz, Greg A.; Glass, Sara; Kamer, Brian; Klennert, Wade L.; Hostutler, David A.

    2012-06-01

    Atmospheric propagation properties of various laser systems, including diode pumped alkali lasers (DPALs) and the Chemical Oxygen Iodine Laser (COIL), are of importance. However, there appears to be a lack of highly accurate transmission characteristics of these systems associated with their operating conditions. In this study laser propagation of the rubidium-based DPAL and the COIL has been simulated utilizing integrated cavity output spectroscopy. This technique allowed for the simulation of laser propagation approaching distances of 3 kilometers on a test stand only 35 cm long. The spectral output from these simulations was compared to the HITRAN database with excellent agreement. The spectral prole and proximity of the laser line to the atmospheric absorbers is shown. These low pressure spectral proles were then extrapolated to higher pressures using an in-house hyperne model. These models allowed for the comparison of proposed systems and their output spectral prole. The diode pumped rubidium laser at pressures under an atmosphere has been shown to interact with only one water absorption feature, but at pressures approaching 7 atmospheres the D1 transition may interact with more than 6 water lines depending on resonator considerations. Additionally, a low pressure system may have some slight control of the overlap of the output prole with the water line by changing the buer gases.

  20. Systems and methods for predicting materials properties

    DOEpatents

    Ceder, Gerbrand; Fischer, Chris; Tibbetts, Kevin; Morgan, Dane; Curtarolo, Stefano

    2007-11-06

    Systems and methods for predicting features of materials of interest. Reference data are analyzed to deduce relationships between the input data sets and output data sets. Reference data includes measured values and/or computed values. The deduced relationships can be specified as equations, correspondences, and/or algorithmic processes that produce appropriate output data when suitable input data is used. In some instances, the output data set is a subset of the input data set, and computational results may be refined by optionally iterating the computational procedure. To deduce features of a new material of interest, a computed or measured input property of the material is provided to an equation, correspondence, or algorithmic procedure previously deduced, and an output is obtained. In some instances, the output is iteratively refined. In some instances, new features deduced for the material of interest are added to a database of input and output data for known materials.

  1. 48 CFR 45.105 - Contractors' property management system compliance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contractors' property management system compliance. 45.105 Section 45.105 Federal Acquisition Regulations System FEDERAL... the contractor's property management policies, procedures, practices, and systems. This analysis...

  2. The Thermodynamic Properties of Some Integrable Systems.

    NASA Astrophysics Data System (ADS)

    Lee, Kong-Ju-Bock

    I discuss the thermodynamic properties of integrable quantum systems, in particular, generalizations of the Heisenberg chain and the one-dimensional Hubbard model, by making use of the Bethe-Ansatz technique. For the Heisenberg chain the following properties are obtained: (1) The critical behavior of the SU(2) invariant ferromagnet with spin S is studied, yielding critical exponents alpha = -1/2, nu = 1, and gamma = 2 for the specific heat, the correlation length, and the susceptibility, respectively. (2) An integrable SU(2) invariant model of the spin 1 Heisenberg chain interacting with an impurity of spin S is constructed. At low temperature for ferromagnetic coupling the impurity follows the critical behavior of the chain, i.e., alpha = -1/2 and gamma = 2. For antiferromagnetic coupling the impurity susceptibility for S = 1/2 diverges logarithmically as H to 0, while for S > 1 the impurity spin is partially compensated by the spins of the chain. (3) The linear coefficient gamma of the low temperature specific heat for the S = 1/2 Heisenberg antiferromagnetic chain is anomalous as H to 0, i.e.,limlimits _{Tto 0} limlimits _{Hto 0} gamma = 2/3 ne limlimits_{Hto 0 } limlimits_{Tto 0} gamma = [ 1+(e/pi) ^{1/2}]/3.. I obtained the following results for the one-dimensional Hubbard model: (1) The thermodynamic Bethe-Ansatz equations for the Hubbard chain with an attractive on-site interaction U are derived. The results are discussed in special limits, e.g., U to infty, U to 0, T to infty, and T to 0. (2) The thermodynamic integral equations for the attractive Hubbard chain are solved numerically at low temperature. At low T the dominant states consist of Cooper pairs and their excitations. A critical field is obtained at T = 0, which disappears for T ne 0. the dependence of the low temperature specific heat coefficient gamma on band filling and magnetic field is obtained. The excitation spectrum is discussed in the context of superconductivity and resonant valence

  3. Mechanical properties of thermal protection system materials.

    SciTech Connect

    Hardy, Robert Douglas; Bronowski, David R.; Lee, Moo Yul; Hofer, John H.

    2005-06-01

    An experimental study was conducted to measure the mechanical properties of the Thermal Protection System (TPS) materials used for the Space Shuttle. Three types of TPS materials (LI-900, LI-2200, and FRCI-12) were tested in 'in-plane' and 'out-of-plane' orientations. Four types of quasi-static mechanical tests (uniaxial tension, uniaxial compression, uniaxial strain, and shear) were performed under low (10{sup -4} to 10{sup -3}/s) and intermediate (1 to 10/s) strain rate conditions. In addition, split Hopkinson pressure bar tests were conducted to obtain the strength of the materials under a relatively higher strain rate ({approx}10{sup 2} to 10{sup 3}/s) condition. In general, TPS materials have higher strength and higher Young's modulus when tested in 'in-plane' than in 'through-the-thickness' orientation under compressive (unconfined and confined) and tensile stress conditions. In both stress conditions, the strength of the material increases as the strain rate increases. The rate of increase in LI-900 is relatively small compared to those for the other two TPS materials tested in this study. But, the Young's modulus appears to be insensitive to the different strain rates applied. The FRCI-12 material, designed to replace the heavier LI-2200, showed higher strengths under tensile and shear stress conditions. But, under a compressive stress condition, LI-2200 showed higher strength than FRCI-12. As far as the modulus is concerned, LI-2200 has higher Young's modulus both in compression and in tension. The shear modulus of FRCI-12 and LI-2200 fell in the same range.

  4. 48 CFR 2945.104 - Review and correction of contractors' property control systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... contractors' property control systems. 2945.104 Section 2945.104 Federal Acquisition Regulations System... contractors' property control systems. When the Government's property administrator determines that review and approval of the contractor's property control system rests with DOL, the Government's...

  5. 48 CFR 2945.104 - Review and correction of contractors' property control systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... contractors' property control systems. 2945.104 Section 2945.104 Federal Acquisition Regulations System... contractors' property control systems. When the Government's property administrator determines that review and approval of the contractor's property control system rests with DOL, the Government's...

  6. 25 CFR 900.52 - What type of property is the property management system required to track?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false What type of property is the property management system...-DETERMINATION AND EDUCATION ASSISTANCE ACT Standards for Tribal or Tribal Organization Management Systems Property Management System Standards § 900.52 What type of property is the property management...

  7. On the problem of discrete-event systems properties preservation

    NASA Astrophysics Data System (ADS)

    Nagul, Nadezhda; Bychkov, Igor

    2017-01-01

    The paper presents a novel approach to solving a problem generally arising in studying dynamical systems, namely the problem of a system's properties preservation under some transformation. Combining algebra, logic and dynamics, the method of logical-algebraic equations (LAE-method) is developed, serving to synthesize criteria for preservation properties of systems connected by special type of morphisms. The LAE-method is applicable to various systems, but we focus on the case of discrete-event systems (DES), which are the systems that evolve in time due to the occurrence of some event sequences. We consider the issues of the LAE-method application to the reduction of supervisor for DES, the problems of DES basic properties, such as observability and controllability, preservation when sensor readings provide information about system's state and it is available to a supervisor. Decentralized supervisory control is also addressed, in particular, the question whether local supervisors properties are inherited in a global supervisor.

  8. Tillage system affects microbiological properties of soil

    NASA Astrophysics Data System (ADS)

    Delgado, A.; de Santiago, A.; Avilés, M.; Perea, F.

    2012-04-01

    Soil tillage significantly affects organic carbon accumulation, microbial biomass, and subsequently enzymatic activity in surface soil. Microbial activity in soil is a crucial parameter contributing to soil functioning, and thus a basic quality factor for soil. Since enzymes remain soil after excretion by living or disintegrating cells, shifts in their activities reflect long-term fluctuations in microbial biomass. In order to study the effects of no-till on biochemical and microbiological properties in comparison to conventional tillage in a representative soil from South Spain, an experiment was conducted since 1982 on the experimental farm of the Institute of Agriculture and Fisheries Research of Andalusia (IFAPA) in Carmona, SW Spain (37o24'07''N, 5o35'10''W). The soil at the experimental site was a very fine, montomorillonitic, thermic Chromic Haploxerert (Soil Survey Staff, 2010). A randomized complete block design involving three replications and the following two tillage treatments was performed: (i) Conventional tillage, which involved mouldboard plowing to a depth of 50 cm in the summer (once every three years), followed by field cultivation to a depth of 15 cm before sowing; crop residues being burnt, (ii) No tillage, which involved controlling weeds before sowing by spraying glyphosate and sowing directly into the crop residue from the previous year by using a planter with double-disk openers. For all tillage treatments, the crop rotation (annual crops) consisted of winter wheat, sunflower, and legumes (pea, chickpea, or faba bean, depending on the year), which were grown under rainfed conditions. Enzymatic activities (ß-glucosidase, dehydrogenase, aryl-sulphatase, acid phosphatase, and urease), soil microbial biomass by total viable cells number by acridine orange direct count, the density of cultivable groups of bacteria and fungi by dilution plating on semi-selective media, the physiological profiles of the microbial communities by BiologR, and the

  9. System for testing properties of a network

    SciTech Connect

    Rawle, Michael; Bartholomew, David B.; Soares, Marshall A.

    2009-06-16

    A method for identifying properties of a downhole electromagnetic network in a downhole tool sting, including the step of providing an electromagnetic path intermediate a first location and a second location on the electromagnetic network. The method further includes the step of providing a receiver at the second location. The receiver includes a known reference. The analog signal includes a set amplitude, a set range of frequencies, and a set rate of change between the frequencies. The method further includes the steps of sending the analog signal, and passively modifying the signal. The analog signal is sent from the first location through the electromagnetic path, and the signal is modified by the properties of the electromagnetic path. The method further includes the step of receiving a modified signal at the second location and comparing the known reference to the modified signal.

  10. Fatigue properties of shuttle thermal protection system

    NASA Technical Reports Server (NTRS)

    Sawyer, J. W.; Cooper, P. A.

    1980-01-01

    Static and cyclic load tests were conducted to determine the static and fatigue strength of the RIS tile/SIP thermal protection system used on the orbiter of the space shuttle. The material systems investigated include the densified and undensified LI-900 tile system on the .40 cm thick SIP and the densified and undensified LI-2200 tile system on the .23 cm (.090 inch) thick SIP. The tests were conducted at room temperature with a fully reversed uniform cyclic loading at 1 Hertz. Cyclic loading causes a relatively large reduction in the stress level that each of the SIP/tile systems can withstand for a small number of cycles. For example, the average static strength of the .40 cm thick SIP/LI-900 tile system is reduced from 86 kPa to 62 kPa for a thousand cycles. Although the .23 cm thick SIP/LI-2200 tile system has a higher static strength, similar reductions in the fatigue strength are noted. Densifying the faying surface of the RSI tile changes the failure mode from the SIP/tile interface to the parent RSI or the SIP and thus greatly increases the static strength of the system. Fatigue failure for the densified tile system, however, occurs due to complete separation or excessive elongation of the SIP and the fatigue strength is only slightly greater than that for the undensified tile system.

  11. Groups graded by root systems and property (T)

    PubMed Central

    Ershov, Mikhail; Jaikin-Zapirain, Andrei; Kassabov, Martin; Zhang, Zezhou

    2014-01-01

    We establish property (T) for a large class of groups graded by root systems, including elementary Chevalley groups and Steinberg groups of rank at least 2 over finitely generated commutative rings with 1. We also construct a group with property (T) which surjects onto all finite simple groups of Lie type and rank at least two. PMID:25425669

  12. An ontology on property for physical, chemical, and biological systems.

    PubMed

    Dybkaer, René

    2004-01-01

    Current metrological literature, including the International vocabulary of basic and general terms in metrology (VIM 1993), presents a special language slowly evolved without consistent use of the procedures of terminological work; furthermore, nominal properties are excluded by definition. Both deficiencies create problems in fields, such as laboratory medicine, which have to report results of all types of property, preferably in a unified systematic format. The present text aims at forming a domain ontology around "property", with intensional definitions and systematic terms, mainly using the terminological tools--with some additions--provided by the International Standards ISO 704, 1087-1, and 10241. "System" and "component" are defined, "quantity" is discussed, and the generic concept "property" is given as 'inherent state- or process-descriptive feature of a system including any pertinent components'. Previously, the term 'kind-of-quantity' and quasi-synonyms have been used as primitives; the proposed definition of "kind-of-property" is 'common defining aspect of mutually comparable properties'. "Examination procedure", "examination method", "examination principle", and "examination" are defined, avoiding the term 'test'. The need to distinguish between instances of "characteristic", "property", "type of characteristic", "kind-of-property", and "property value" is emphasized; the latter is defined together with "property value scale". These fundamental concepts are presented in a diagram, and the effect of adding essential characteristics to give expanded definitions is exemplified. Substitution usually leads to unwieldy definitions, but reveals circularity as does exhaustive consecutive listing of defining concepts. The top concept <property> may be generically divided according to many terminological dimensions, especially regarding which operators are allowed among the four sets =, not equal to; <, >; +, -; and x, :. The coordinate concepts defined are

  13. Thermodynamic properties of a polydisperse system

    NASA Astrophysics Data System (ADS)

    Tutschka, Christian; Kahl, Gerhard

    2001-09-01

    We use the virial theorem to derive a closed analytic form of the Helmholtz free energy for a polydisperse system of sticky hard spheres (SHS) within the mean spherical model (MSM). To this end we calculate the free energy of the MSM for an N-component mixture of SHS via the virial route and apply to it-after imposing a Lorentz-Berthelot type rule on the interactions-the stochastic (i.e., polydisperse) limit. The resulting excess free energy of this polydisperse system is of the truncatable moment free energy format. We also discuss the compressibility and the energy routes.

  14. Extension of Generalized Fluid System Simulation Program's Fluid Property Database

    NASA Technical Reports Server (NTRS)

    Patel, Kishan

    2011-01-01

    This internship focused on the development of additional capabilities for the General Fluid Systems Simulation Program (GFSSP). GFSSP is a thermo-fluid code used to evaluate system performance by a finite volume-based network analysis method. The program was developed primarily to analyze the complex internal flow of propulsion systems and is capable of solving many problems related to thermodynamics and fluid mechanics. GFSSP is integrated with thermodynamic programs that provide fluid properties for sub-cooled, superheated, and saturation states. For fluids that are not included in the thermodynamic property program, look-up property tables can be provided. The look-up property tables of the current release version can only handle sub-cooled and superheated states. The primary purpose of the internship was to extend the look-up tables to handle saturated states. This involves a) generation of a property table using REFPROP, a thermodynamic property program that is widely used, and b) modifications of the Fortran source code to read in an additional property table containing saturation data for both saturated liquid and saturated vapor states. Also, a method was implemented to calculate the thermodynamic properties of user-fluids within the saturation region, given values of pressure and enthalpy. These additions required new code to be written, and older code had to be adjusted to accommodate the new capabilities. Ultimately, the changes will lead to the incorporation of this new capability in future versions of GFSSP. This paper describes the development and validation of the new capability.

  15. Masking properties of APD communication systems

    NASA Astrophysics Data System (ADS)

    Fernandez, J. G.; Larrondo, H. A.; Slavin, H. A.; Levin, D. G.; Hidalgo, R. M.; Rivera, R. R.

    2003-10-01

    In this paper, we explore the ability of wavelet multilevel analysis to unmask the information hidden in a chaotic mask. This digital filtering technique has been recently reported as particularly well suited for the detection of coherent structures. In a recent paper the capability of wavelets to unmask a message, in cases where a chaotic signal is just added to the information, has also been demonstrated. The case of an active passive decomposition scheme, where message is mixed with the chaotic signal, is studied here. A representative case employing Daubechies wavelets and a typical Rossler-oscillator-based communication system is reported. Using a time scaling parameter modifies the spectrum of the mask. The results show that wavelets are effective only in particular cases with poor masking. The fast Fourier transform analysis demonstrates that the spectrum of the chaotic mask shows no holes and then other digital filtering techniques such as Wiener filters or comb filters must also been disregarded.

  16. Chemosensory properties of the trigeminal system.

    PubMed

    Viana, Félix

    2011-01-19

    The capacity of cutaneous, including trigeminal endings, to detect chemicals is known as chemesthesis or cutaneous chemosensation. This sensory function involves the activation of nociceptor and thermoreceptor endings and has a protective or defensive function, as many of these substances are irritants or poisonous. However, humans have also developed a liking for the distinct sharpness or pungency of many foods, beverages, and spices following activation of the same sensory afferents. Our understanding of the cellular and molecular mechanisms of chemosensation in the trigeminal system has experienced enormous progress in the past decade, following the cloning and functional characterization of several ion channels activated by physical and chemical stimuli. This brief review attempts to summarize our current knowledge in this field, including a functional description of various sensory channels, especially TRP channels, involved in trigeminal chemosensitivy. Finally, some of these new findings are discussed in the context of the pathophysiology of trigeminal chemosensation, including pain, pruritus, migraine, cough, airway inflammation, and ophthalmic diseases.

  17. Stability properties of nonlinear dynamical systems and evolutionary stable states

    NASA Astrophysics Data System (ADS)

    Gleria, Iram; Brenig, Leon; Rocha Filho, Tarcísio M.; Figueiredo, Annibal

    2017-03-01

    In this paper we address the problem of stability in a general class of non-linear systems. We establish a link between the concepts of asymptotic stable interior fixed points of square Quasi-Polynomial systems and evolutionary stable states, a property of some payoff matrices arising from evolutionary games.

  18. Cryogenic compressive properties of basic epoxy resin systems

    SciTech Connect

    Markley, F.W.; Hoffman, J.A.; Muniz, D.P.

    1985-09-01

    The compressive properties of short cylindrical samples of many different epoxy resin systems have been measured at ambient temperature and at 77/sup 0/K. These are pure resin systems of known chemistry, without the inorganic fillers or fibrous reinforcements needed in final cryogenic systems. Of course, chemically incorporated modifiers such as flexibilizing resins have been included. This data should make possible inferences about cryogenic properties from molecular structures and provide specific data useful to formulators and end users. Measurements on some other plastics such as PTFE, Polyimides, and UHMWPE have been made for comparison purposes.

  19. Electronic Properties of Low-Dimensional Systems

    NASA Astrophysics Data System (ADS)

    Rodin, Aleksandr

    This work deals with transport and general electronic phenomena in low-dimensional systems. The first chapter is dedicated to Variable Range Hopping. It starts with a brief review of the general hopping formalism, based on previous work. Next, new methods and results are presented and discussed. In particular, studies of both Ohmic and non-Ohmic regime are performed and the stark differences between the two are elucidated. In addition, apparent power law dependence of current on voltage in disordered one-dimensional materials is analyzed. The results obtained compare favorably with the experiments. Finally, the behavior of the conducting network in d dimensions is discussed using the percolation approach. The second chapter deals with plasmonic effects in graphene. After giving a short introduction to graphene and plasmonic behavior, current work is presented. Charge oscillations in graphene half-plane are discussed and compared with experimental results obtained from near-field microscopy. In addition, plasmonic oscillations in a "narrow-flake" geometry are analyzed analytically and numerically, showing good agreement between the two methods.

  20. 48 CFR 252.245-7003 - Contractor Property Management System Administration.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... property system that complies with the system criteria in paragraph (c) of this clause. Property management... management system. Failure to maintain an acceptable property management system, as defined in this clause...) System criteria. The Contractor's property management system shall be in accordance with paragraph (f)...

  1. 41 CFR 101-1.101 - Federal Property Management Regulations System.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Management Regulations System. 101-1.101 Section 101-1.101 Public Contracts and Property Management Federal Property Management Regulations System FEDERAL PROPERTY MANAGEMENT REGULATIONS GENERAL 1-INTRODUCTION 1.1-Regulation System § 101-1.101 Federal Property Management Regulations System. The Federal Property...

  2. Electronic properties of graphene-based bilayer systems

    NASA Astrophysics Data System (ADS)

    Rozhkov, A. V.; Sboychakov, A. O.; Rakhmanov, A. L.; Nori, Franco

    2016-08-01

    This article reviews the theoretical and experimental work related to the electronic properties of bilayer graphene systems. Three types of bilayer stackings are discussed: the AA, AB, and twisted bilayer graphene. This review covers single-electron properties, effects of static electric and magnetic fields, bilayer-based mesoscopic systems, spin-orbit coupling, dc transport and optical response, as well as spontaneous symmetry violation and other interaction effects. The selection of the material aims to introduce the reader to the most commonly studied topics of theoretical and experimental research in bilayer graphene.

  3. "TPSX: Thermal Protection System Expert and Material Property Database"

    NASA Technical Reports Server (NTRS)

    Squire, Thomas H.; Milos, Frank S.; Rasky, Daniel J. (Technical Monitor)

    1997-01-01

    The Thermal Protection Branch at NASA Ames Research Center has developed a computer program for storing, organizing, and accessing information about thermal protection materials. The program, called Thermal Protection Systems Expert and Material Property Database, or TPSX, is available for the Microsoft Windows operating system. An "on-line" version is also accessible on the World Wide Web. TPSX is designed to be a high-quality source for TPS material properties presented in a convenient, easily accessible form for use by engineers and researchers in the field of high-speed vehicle design. Data can be displayed and printed in several formats. An information window displays a brief description of the material with properties at standard pressure and temperature. A spread sheet window displays complete, detailed property information. Properties which are a function of temperature and/or pressure can be displayed as graphs. In any display the data can be converted from English to SI units with the click of a button. Two material databases included with TPSX are: 1) materials used and/or developed by the Thermal Protection Branch at NASA Ames Research Center, and 2) a database compiled by NASA Johnson Space Center 9JSC). The Ames database contains over 60 advanced TPS materials including flexible blankets, rigid ceramic tiles, and ultra-high temperature ceramics. The JSC database contains over 130 insulative and structural materials. The Ames database is periodically updated and expanded as required to include newly developed materials and material property refinements.

  4. Delocalization and scaling properties of low-dimensional quasiperiodic systems

    NASA Astrophysics Data System (ADS)

    Guo, Ai-Min; Xie, X. C.; Sun, Qing-feng

    2014-02-01

    In this paper, we explore the localization transition and the scaling properties of both quasi-one-dimensional and two-dimensional quasiperiodic systems, which are constituted from coupling several Aubry-André (AA) chains along the transverse direction, in the presence of next-nearest-neighbor (NNN) hopping. The localization length, two-terminal conductance, and participation ratio are calculated within the tight-binding Hamiltonian. Our results reveal that a metal-insulator transition could be driven in these systems not only by changing the NNN hopping integral but also by the dimensionality effects. These results are general and hold by coupling distinct AA chains with various model parameters. Furthermore, we show from finite-size scaling that the transport properties of the two-dimensional quasiperiodic system can be described by a single parameter and the scaling function can reach the value 1, contrary to the scaling theory of localization of disordered systems. The underlying physical mechanism is discussed.

  5. Mass properties measurement system: Dynamics and statics measurements

    NASA Technical Reports Server (NTRS)

    Doty, Keith L.

    1993-01-01

    This report presents and interprets experimental data obtained from the Mass Properties Measurement System (MPMS). Statics measurements yield the center-of-gravity of an unknown mass and dynamics measurements yield its inertia matrix. Observations of the MPMS performance has lead us to specific design criteria and an understanding of MPMS limitations.

  6. Perceptual uncertainty is a property of the cognitive system.

    PubMed

    Perea, Manuel; Carreiras, Manuel

    2012-10-01

    We qualify Frost's proposals regarding letter-position coding in visual word recognition and the universal model of reading. First, we show that perceptual uncertainty regarding letter position is not tied to European languages-instead it is a general property of the cognitive system. Second, we argue that a universal model of reading should incorporate a developmental view of the reading process.

  7. Addiction as a function of action system properties.

    PubMed

    Loonis, E; Apter, M J; Sztulman, H

    2000-01-01

    Generalising from some previous analyses of addiction and introducing the concept of an action system which governs all actions which are focused on what Brown (1988) calls "hedonic management," we argue that addictions of every kind involve an action system that displays high salience, low variety, and low vicariance. Addictions also involve what Apter (1982) calls the "paratelic state." A study was carried out comparing 31 drug addicts with 29 control subjects in terms of action system variables. To measure these variables, we constructed a new instrument, the Activity-System Drawing Test, and also used the Telic Dominance Scale to measure frequency of paratelic states. Dysphoria was measured by means of the BATE (anxiety), IDA-13 (depression), SEI (self-esteem), and TAS-20 (alexithymia) instruments. Strong significant differences were found between groups for both action system variables and dysphoria. This supports the idea that addictions emerge from systemic properties of the action system.

  8. Soil properties mapping with the DIGISOIL multi-sensor system

    NASA Astrophysics Data System (ADS)

    Grandjean, G.

    2012-04-01

    The multidisciplinary DIGISOIL project aimed to integrate and improve in situ and proximal measurement technologies for the assessment of soil properties and soil degradation indicators, going from the sensing technologies to their integration and their application in (digital) soil mapping (DSM). In order to assess and prevent soil degradation and to benefit from the different ecological, economical and historical functions of the soil in a sustainable way, high resolution and quantitative maps of soil properties are needed. The core objective of the project is to explore and exploit new capabilities of advanced geophysical technologies for answering this societal demand. To this aim, DIGISOIL addresses four issues covering technological, soil science and economic aspects: (i) the validation of geophysical (in situ, proximal and airborne) technologies and integrated pedo-geophysical inversion techniques (mechanistic data fusion) (ii) the relation between the geophysical parameters and the soil properties, (iii) the integration of the derived soil properties for mapping soil functions and soil threats, (iv) the pre-evaluation, standardisation and sub-industrialization of the proposed methodologies, including technical and economical studies related to the societal demand. With respect to these issues, the DIGISOIL project allows to develop, test and validate the most relevant geophysical technologies for mapping soil properties. The system was tested on different field tests, and validated the proposed technologies and solutions for each of the identified methods: geoelectric, GPR, EMI, seismics, magnetic and hyperspectral. After data acquisition systems, sensor geometry, and advanced data processing techniques have been developed and validated, we present now the solutions for going from geophysical data to soil properties maps. For two test sites, located respectively in Luxembourg (LU) and Mugello (IT) a set of soil properties maps have been produced. They give

  9. Statistical properties of chaotic dynamical systems which exhibit strange attractors

    SciTech Connect

    Jensen, R.V.; Oberman, C.R.

    1981-07-01

    A path integral method is developed for the calculation of the statistical properties of turbulent dynamical systems. The method is applicable to conservative systems which exhibit a transition to stochasticity as well as dissipative systems which exhibit strange attractors. A specific dissipative mapping is considered in detail which models the dynamics of a Brownian particle in a wave field with a broad frequency spectrum. Results are presented for the low order statistical moments for three turbulent regimes which exhibit strange attractors corresponding to strong, intermediate, and weak collisional damping.

  10. Optoelectronic properties of nanostructured ensembles controlled by biomolecular logic systems.

    PubMed

    Pita, Marcos; Krämer, Melina; Zhou, Jian; Poghossian, Arshak; Schöning, Michael J; Fernández, Víctor M; Katz, Evgeny

    2008-10-28

    A nanostructured system composed of enzyme-functionalized silica microparticles, ca. 74 microm, and gold-coated magnetic nanoparticles, 18 +/- 3 nm, modified with pH-sensitive organic shells was used to process biochemical signals and transduce the output signal into the changes of the optoelectronic properties of the assembly. The enzymes (glucose oxidase, invertase, esterase) covalently bound to the silica microparticles performed Boolean logic operations AND/OR processing biochemical information received in the form of chemical input signals resulting in changes of the solution pH value. Dissociation state of the organic shells on the gold-coated magnetic nanoparticles was controlled by pH changes generated in situ by the enzyme logic systems. The charge variation on the organic shells upon the reversible protonation/dissociation process resulted in the changes of the gold layer localized surface plasmon resonance energy (LSPR), thus producing optical changes in the system. The proton transfer process allowed the functional coupling of the information processing enzyme systems with the signal transducing gold-coated magnetic nanoparticles providing their cooperative performance. Magnetic properties of the gold-coated magnetic nanoparticles allowed separation of the signal-transducing nanoparticles from the enzyme-modified signal processing silica microparticles. The reversible system operation was achieved by the Reset function, returning the pH value and optical properties of the system to the initial state. This process was biocatalyzed by another immobilized enzyme (urease) activated with a biochemical signal. The studied approach opens the way to novel optical biosensors logically processing multiple biochemical signals and "smart" multisignal responsive materials with logically switchable optical properties.

  11. Volume-controlled hydrologic property measurements in triaxial systems

    USGS Publications Warehouse

    Olsen, Harold W.; Willden, Arthur T.; Kiusalaas, Nicholas J.; Nelson, Karl R.; Poeter, Eileen P.

    1994-01-01

    New capabilities for hydrologic property measurements in triaxial systems include: (1) volume-controlled and simultaneous measurements of hydraulic conductivity and one-dimensional consolidation (or specific storage) of a saturated test specimen; and (2) volume-controlled measurements of hydraulic conductivity, matric potential, and the variation of these properties with the moisture content of an unsaturated test specimen. Data on saturated kaolinite demonstrate simultaneous hydraulic-conductivity and one-dimensional consolidation tests with continuous monitoring of both vertical and horizontal effective stresses. Data on well-graded silty sand demonstrate the feasibility of concurrent constant-flow hydraulic conductivity and mattic potential measurements, and the variation of these properties with moisture content, for undisturbed and unsaturated specimens mounted in triaxial cells. Refinements needed to realize the full potential of these capabilities include a more rigid triaxial cell to minimize compliance, and an improved technique for measuring hydraulic-head differences within an unsaturated test specimen.

  12. Engineering Biomaterial Properties for Central Nervous System Applications

    NASA Astrophysics Data System (ADS)

    Rivet, Christopher John

    Biomaterials offer unique properties that are intrinsic to the chemistry of the material itself or occur as a result of the fabrication process; iron oxide nanoparticles are superparamagnetic, which enables controlled heating in the presence of an alternating magnetic field, and a hydrogel and electrospun fiber hybrid material provides minimally invasive placement of a fibrous, artificial extracellular matrix for tissue regeneration. Utilization of these unique properties towards central nervous system disease and dysfunction requires a thorough definition of the properties in concert with full biological assessment. This enables development of material-specific features to elicit unique cellular responses. Iron oxide nanoparticles are first investigated for material-dependent, cortical neuron cytotoxicity in vitro and subsequently evaluated for alternating magnetic field stimulation induced hyperthermia, emulating the clinical application for enhanced chemotherapy efficacy in glioblastoma treatment. A hydrogel and electrospun fiber hybrid material is first applied to a rat brain to evaluate biomaterial interface astrocyte accumulation as a function of hybrid material composition. The hybrid material is then utilized towards increasing functional engraftment of dopaminergic progenitor neural stem cells in a mouse model of Parkinson's disease. Taken together, these two scenarios display the role of material property characterization in development of biomaterial strategies for central nervous system repair and regeneration.

  13. Modeling of rheological properties for entangled polymer systems

    NASA Astrophysics Data System (ADS)

    Banerjee, Nilanjana

    The study of entangled polymer rheology both in the field of medicine and polymer processing has their major importance. Mechanical properties of biomolecules are studied in order to better understand cellular behavior. Similarly, industrial processing of polymers needs thorough understanding of rheology so as to improve process techniques. Work in this dissertation has been organized into three major sections. Firstly, numerical/analytical models are reviewed for describing rheological properties and mechanical behaviors of cytoskeleton. The cytoskeleton models are classified into categories according to the length scales of the phenomena of interest. The main principles and characteristics of each model are summarized and discussed by comparison with each other, thus providing a systematic understanding of biopolymer network modeling. Secondly, a new constitutive "toy" Mead-Banerjee-Park (MBP) model is developed for monodisperse entangled polymer systems, by introducing the idea of a configuration dependent friction coefficient (CDFC) and entanglement dynamics (ED) into the MLD "toy" model. The model is tested against experimental data in steady and transient extensional and shear flows. The model simultaneously captures the monotonic thinning of the extensional flow curve of polystyrene (PS) melts and the extension hardening found in PS solutions. Thirdly, the monodisperse MBP model is accordingly modified into polydisperse MBP "toy" constitutive model to predict the nonlinear viscoelastic material properties of model polydisperse systems. The polydisperse MBP toy model accurately predicts the material properties in the forward direction for transient uniaxial extension and transient shear flow.

  14. Quasi-Three Body Systems: Properties and Scattering

    NASA Astrophysics Data System (ADS)

    Amusia, M. Ya.

    2017-03-01

    We investigate systems of three mutually interacting particles with masses m_e, m_μ , M that obey the following inequality m_e ≪ m_μ ≪ M. Then the three-body problem reduces to the two-body scattering or structure of m_e in the field of the pseudo-nucleus m_μ M. We calculate analytically the properties of considered systems, such as the scattering cross-sections, hyperfine splitting, Auger decay of exited states and Lamb shits, presenting them as expansions in powers of the parameter β = m_e/m_μ ≪ 1.

  15. The properties of probabilistic simple regular sticker system

    NASA Astrophysics Data System (ADS)

    Selvarajoo, Mathuri; Fong, Wan Heng; Sarmin, Nor Haniza; Turaev, Sherzod

    2015-10-01

    A mathematical model for DNA computing using the recombination behavior of DNA molecules, known as a sticker system, has been introduced in 1998. In sticker system, the sticker operation is based on the Watson-Crick complementary feature of DNA molecules. The computation of sticker system starts from an incomplete double-stranded sequence. Then by iterative sticking operations, a complete double-stranded sequence is obtained. It is known that sticker systems with finite sets of axioms and sticker rule (including the simple regular sticker system) generate only regular languages. Hence, different types of restrictions have been considered to increase the computational power of the languages generated by the sticker systems. In this paper, we study the properties of probabilistic simple regular sticker systems. In this variant of sticker system, probabilities are associated with the axioms, and the probability of a generated string is computed by multiplying the probabilities of all occurrences of the initial strings. The language are selected according to some probabilistic requirements. We prove that the probabilistic enhancement increases the computational power of simple regular sticker systems.

  16. Critical properties of dissipative quantum spin systems in finite dimensions

    NASA Astrophysics Data System (ADS)

    Takada, Kabuki; Nishimori, Hidetoshi

    2016-10-01

    We study the critical properties of finite-dimensional dissipative quantum spin systems with uniform ferromagnetic interactions. Starting from the transverse field Ising model coupled to a bath of harmonic oscillators with Ohmic spectral density, we generalize its classical representation to classical spin systems with O(n) symmetry and then take the large-n limit to reduce the system to a spherical model. The exact solution to the resulting spherical model with long-range interactions along the imaginary time axis shows a phase transition with static critical exponents coinciding with those of the conventional short-range spherical model in d+2 dimensions, where d is the spatial dimensionality of the original quantum system. This implies that the dynamical exponent is z = 2. These conclusions are consistent with the results of Monte Carlo simulations and renormalization group calculations for dissipative transverse field Ising and O(n) models in one and two dimensions. The present approach therefore serves as a useful tool for analytically investigating the properties of quantum phase transitions of the dissipative transverse field Ising and other related models. Our method may also offer a platform to study more complex phase transitions in dissipative finite-dimensional quantum spin systems, which have recently received renewed interest in the context of quantum annealing in a noisy environment.

  17. Geometric and asymptotic properties associated with linear switched systems

    NASA Astrophysics Data System (ADS)

    Chitour, Y.; Gaye, M.; Mason, P.

    2015-12-01

    Consider a continuous-time linear switched system on Rn associated with a compact convex set of matrices. When it is irreducible and its largest Lyapunov exponent is zero there always exists a Barabanov norm associated with the system. This paper deals with two types of issues: (a) properties of Barabanov norms such as uniqueness up to homogeneity and strict convexity; (b) asymptotic behavior of the extremal solutions of the linear switched system. Regarding Issue (a), we provide partial answers and propose four related open problems. As for Issue (b), we establish, when n = 3, a Poincaré-Bendixson theorem under a regularity assumption on the set of matrices. We then revisit a noteworthy result of N.E. Barabanov describing the asymptotic behavior of linear switched system on R3 associated with a pair of Hurwitz matrices { A , A + bcT }. After pointing out a gap in Barabanov's proof we partially recover his result by alternative arguments.

  18. Thermophysical and Thermomechanical Properties of Thermal Barrier Coating Systems

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    2000-01-01

    Thermal barrier coatings have been developed for advanced gas turbine and diesel engine applications to improve engine reliability and fuel efficiency. However, the issue of coating durability under high temperature cyclic conditions is still of major concern. The coating failure is closely related to thermal stresses and oxidation in the coating systems. Coating shrinkage cracking resulting from ceramic sintering and creep at high temperatures can further accelerate the coating failure process. The purpose of this paper is to address critical issues such as ceramic sintering and creep, thermal fatigue and their relevance to coating life prediction. Novel test approaches have been established to obtain critical thermophysical and thermomechanical properties of the coating systems under near-realistic temperature and stress gradients encountered in advanced engine systems. Emphasis is placed on the dynamic changes of the coating thermal conductivity and elastic modulus, fatigue and creep interactions, and resulting failure mechanisms during the simulated engine tests. Detailed experimental and modeling results describing processes occurring in the thermal barrier coating systems provide a framework for developing strategies to manage ceramic coating architecture, microstructure and properties.

  19. Fractal variability: An emergent property of complex dissipative systems

    NASA Astrophysics Data System (ADS)

    Seely, Andrew J. E.; Macklem, Peter

    2012-03-01

    The patterns of variation of physiologic parameters, such as heart and respiratory rate, and their alteration with age and illness have long been under investigation; however, the origin and significance of scale-invariant fractal temporal structures that characterize healthy biologic variability remain unknown. Quite independently, atmospheric and planetary scientists have led breakthroughs in the science of non-equilibrium thermodynamics. In this paper, we aim to provide two novel hypotheses regarding the origin and etiology of both the degree of variability and its fractal properties. In a complex dissipative system, we hypothesize that the degree of variability reflects the adaptability of the system and is proportional to maximum work output possible divided by resting work output. Reductions in maximal work output (and oxygen consumption) or elevation in resting work output (or oxygen consumption) will thus reduce overall degree of variability. Second, we hypothesize that the fractal nature of variability is a self-organizing emergent property of complex dissipative systems, precisely because it enables the system's ability to optimally dissipate energy gradients and maximize entropy production. In physiologic terms, fractal patterns in space (e.g., fractal vasculature) or time (e.g., cardiopulmonary variability) optimize the ability to deliver oxygen and clear carbon dioxide and waste. Examples of falsifiability are discussed, along with the need to further define necessary boundary conditions. Last, as our focus is bedside utility, potential clinical applications of this understanding are briefly discussed. The hypotheses are clinically relevant and have potential widespread scientific relevance.

  20. Model Checking Linear-Time Properties of Probabilistic Systems

    NASA Astrophysics Data System (ADS)

    Baier, Christel; Größer, Marcus; Ciesinski, Frank

    This chapter is about the verification of Markov decision processes (MDPs) which incorporate one of the fundamental models for reasoning about probabilistic and nondeterministic phenomena in reactive systems. MDPs have their roots in the field of operations research and are nowadays used in a wide variety of areas including verification, robotics, planning, controlling, reinforcement learning, economics and semantics of randomized systems. Furthermore, MDPs served as the basis for the introduction of probabilistic automata which are related to weighted automata. We describe the use of MDPs as an operational model for randomized systems, e.g., systems that employ randomized algorithms, multi-agent systems or systems with unreliable components or surroundings. In this context we outline the theory of verifying ω-regular properties of such operational models. As an integral part of this theory we use ω-automata, i.e., finite-state automata over finite alphabets that accept languages of infinite words. Additionally, basic concepts of important reduction techniques are sketched, namely partial order reduction of MDPs and quotient system reduction of the numerical problem that arises in the verification of MDPs. Furthermore we present several undecidability and decidability results for the controller synthesis problem for partially observable MDPs.

  1. Interfacial and mechanical properties of self-assembling systems

    NASA Astrophysics Data System (ADS)

    Carvajal, Daniel

    Self-assembly is a fascinating phenomena where interactions between small subunits allow them to aggregate and form complex structures that can span many length scales. These self-assembled structures are especially important in biology where they are necessary for life as we know it. This dissertation is a study of three very different self-assembling systems, all of which have important connections to biology and biological systems. Drop shape analysis was used to study the interfacial assembly of amphiphilic block copolymers at the oil/water interface. When biologically functionalyzed copolymers are used, this system can serve as a model for receptor-ligand interactions that are used by cells to perform many activities, such as interact with their surroundings. The physical properties of a self-assembling membrane system were quantified using membrane inflation and swelling experiments. These types of membranes may have important applications in medicine such as drug eluting (growth factor eluting) scaffolds to aid in wound healing. The factors affecting the properties of bis(leucine) oxalamide gels were also explored. We believe that this particular system will serve as an appropriate model for biological gels that are made up of fiber-like and/or rod-like structures. During the course of the research presented in this dissertation, many new techniques were developed specifically to allow/aid the study of these distinct self-assembling systems. For example, numerical methods were used to predict drop stability for drop shape analysis experiments and the methods used to create reproducibly create self-assembling membranes were developed specifically for this purpose. The development of these new techniques is an integral part of the thesis and should aid future students who work on these projects. A number ongoing projects and interesting research directions for each one of the projects is also presented.

  2. The paramagnetic properties of ferromagnetic mixed-spin chain system

    NASA Astrophysics Data System (ADS)

    Hu, Ai-Yuan; Wu, Zhi-Min; Cui, Yu-Ting; Qin, Guo-Ping

    2015-01-01

    The double-time Green's function method is used to investigate the paramagnetic properties of ferromagnetic mixed-spin chain system within the random-phase approximation and Anderson-Callen's decoupling approximation. The analytic expressions of the transverse susceptibility, longitudinal susceptibility and correlation length are obtained under transverse and longitudinal magnetic field. Using the analytic expressions of the transverse and longitudinal susceptibility to fit the experimental results, our results well agree with experimental data and the results from the high temperature series expansion within a simple Padé approximation.

  3. Transport properties of the Fermi hard-sphere system

    SciTech Connect

    Mecca, Angela; Lovato, Alessandro; Benhar, Omar; Polls, Artur

    2016-03-01

    The transport properties of neutron star matter play an important role in many astrophysical processes. We report the results of a calculation of the shear viscosity and thermal conductivity coefficients of the hard-sphere fermion system of degeneracy ν = 2, that can be regarded as a model of pure neutron matter. Our approach is based on the effective interaction obtained from the formalism of correlated basis functions and the cluster expansion technique. The resulting transport coefficients show a strong sensitivity to the quasiparticle effective mass, reflecting the effect of second-order contributions to the self-energy that are not taken into account in nuclear matter studies available in the literature.

  4. Control System Upgrade for a Mass Property Measurement Facility

    NASA Technical Reports Server (NTRS)

    Chambers, William; Hinkle, R. Kenneth (Technical Monitor)

    2002-01-01

    The Mass Property Measurement Facility (MPMF) at the Goddard Space Flight Center has undergone modifications to ensure the safety of Flight Payloads and the measurement facility. The MPMF has been technically updated to improve reliability and increase the accuracy of the measurements. Modifications include the replacement of outdated electronics with a computer based software control system, the addition of a secondary gas supply in case of a catastrophic failure to the gas supply and a motor controlled emergency stopping feature instead of a hard stop.

  5. 41 CFR 109-1.5205 - Personal property management system changes.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false Personal property management system changes. 109-1.5205 Section 109-1.5205 Public Contracts and Property Management Federal... Personal property management system changes. Any proposed significant change to a designated...

  6. 41 CFR 109-1.5205 - Personal property management system changes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Personal property management system changes. 109-1.5205 Section 109-1.5205 Public Contracts and Property Management Federal... Personal property management system changes. Any proposed significant change to a designated...

  7. Effects of carbon nanoparticles on properties of thermoset polymer systems

    NASA Astrophysics Data System (ADS)

    Movva, Siva Subramanyam

    Polymer nanocomposites are novel materials in which at least one of the dimensions of the reinforcing material is on the order of 100 nm or less. While thermoplastic nanocomposites have been studied very widely, there are fewer studies concerning the effect of nanoparticles on thermoset systems. Low temperature cure thermoset systems are very important for many important applications. In this study, the processing, mechanical and thermal properties and reaction kinetics of carbon nanofiber (CNF) and/or carbon nanotubes (CNT) reinforced low temperature vinyl ester and epoxy nanocomposites were studied. In the first part, the processing challenge of incorporating CNFs into conventional fiber reinforced composites made by Vacuum infusion resin transfer molding (VARTM) was addressed by a new technique. The CNFs are pre-bound on the long fiber mats, instead of mixing them in the polymer resin, thereby eliminating several processing drawbacks. The resulting hybrid nanocomposites showed significant improvements in tensile, flexural and thermal properties. The effect of CNFs on the mold filling in VARTM was also studied and shown to follow the Darcy's law. In the second part, the effect of CNFs on the low temperature cure kinetics of vinyl ester and epoxy resins is studied using a thermal analysis technique, namely Differential scanning calorimetry (DSC). The effect of CNFs on the free radical polymerization of vinyl esters was found to be very complex as the CNFs interact with the various curing ingredients in the formulation. Specifically, the interaction effects of CNFs and the inhibitor were studied and a reaction mechanism was proposed to explain the observed phenomenon. The effect of surface modification of the carbon nanoparticles on the cure kinetics of wind-blade epoxy was studied. The surface functionalization reduced the activation energy of the epoxy reaction and was found to have an acceleration effect on the cure kinetics of epoxy resin at room temperature

  8. Equilibration properties of a disordered interacting open quantum system

    NASA Astrophysics Data System (ADS)

    van Nieuwenburg, Evert; Huber, Sebastian

    The central question in the field of many body localization is if a closed interacting quantum system effectively thermalizes in the presence of disorder. However, any experimental test necessarily involves the opening of the ideally closed quantum system. Both from a fundamental point of view as well as for concrete experimental investigations of many body localization phenomena, a solid understanding of the effect of an attached bath is of significant importance. We study the equilibration properties of disordered interacting open quantum systems. On the one hand we consider the equilibration of such a many body localized system by coupling baths to the ends of a 1D spin chain. We find non-monotonous behaviour of the slowest relaxation time towards equilibrium. On the other hand, we take the bath itself to be a disordered interacting open quantum system and investigate the dephasing of a single qubit coupled to it. The model for the bath has a many body localization transition, affecting the dephasing of the single qubit.

  9. Thermodynamic properties for polycyclic systems by non-calorimetric methods

    SciTech Connect

    Steele, W.V.; Chirico, R.D.; Klots, T.D.

    1993-03-01

    A detailed vibrational spectroscopic study of furan, pyrrole, and thiophene has been completed. These compounds form part of the base of five-membered ring systems on which the rest of the research program will be built Several methyl-substituted derivatives were also studied. The results will be used to confirm the model for alkyl- substitution in the ring systems. Gas-phase spectra and fundamental- frequency assignments were completed for 2,3- and 2,5-dihydrofuran. Those compounds initiate work on ring-puckering within the research program. A paper describing the need for third virial estimation, when using the virial equation of state to derive thermodynamic properties at pressures greater than 1 bar was completed.

  10. Machine learning strategies for systems with invariance properties

    NASA Astrophysics Data System (ADS)

    Ling, Julia; Jones, Reese; Templeton, Jeremy

    2016-08-01

    In many scientific fields, empirical models are employed to facilitate computational simulations of engineering systems. For example, in fluid mechanics, empirical Reynolds stress closures enable computationally-efficient Reynolds Averaged Navier Stokes simulations. Likewise, in solid mechanics, constitutive relations between the stress and strain in a material are required in deformation analysis. Traditional methods for developing and tuning empirical models usually combine physical intuition with simple regression techniques on limited data sets. The rise of high performance computing has led to a growing availability of high fidelity simulation data. These data open up the possibility of using machine learning algorithms, such as random forests or neural networks, to develop more accurate and general empirical models. A key question when using data-driven algorithms to develop these empirical models is how domain knowledge should be incorporated into the machine learning process. This paper will specifically address physical systems that possess symmetry or invariance properties. Two different methods for teaching a machine learning model an invariance property are compared. In the first method, a basis of invariant inputs is constructed, and the machine learning model is trained upon this basis, thereby embedding the invariance into the model. In the second method, the algorithm is trained on multiple transformations of the raw input data until the model learns invariance to that transformation. Results are discussed for two case studies: one in turbulence modeling and one in crystal elasticity. It is shown that in both cases embedding the invariance property into the input features yields higher performance at significantly reduced computational training costs.

  11. Machine learning strategies for systems with invariance properties

    SciTech Connect

    Ling, Julia; Jones, Reese E.; Templeton, Jeremy Alan

    2016-05-06

    Here, in many scientific fields, empirical models are employed to facilitate computational simulations of engineering systems. For example, in fluid mechanics, empirical Reynolds stress closures enable computationally-efficient Reynolds-Averaged Navier-Stokes simulations. Likewise, in solid mechanics, constitutive relations between the stress and strain in a material are required in deformation analysis. Traditional methods for developing and tuning empirical models usually combine physical intuition with simple regression techniques on limited data sets. The rise of high-performance computing has led to a growing availability of high-fidelity simulation data, which open up the possibility of using machine learning algorithms, such as random forests or neural networks, to develop more accurate and general empirical models. A key question when using data-driven algorithms to develop these models is how domain knowledge should be incorporated into the machine learning process. This paper will specifically address physical systems that possess symmetry or invariance properties. Two different methods for teaching a machine learning model an invariance property are compared. In the first , a basis of invariant inputs is constructed, and the machine learning model is trained upon this basis, thereby embedding the invariance into the model. In the second method, the algorithm is trained on multiple transformations of the raw input data until the model learns invariance to that transformation. Results are discussed for two case studies: one in turbulence modeling and one in crystal elasticity. It is shown that in both cases embedding the invariance property into the input features yields higher performance with significantly reduced computational training costs.

  12. Machine learning strategies for systems with invariance properties

    DOE PAGES

    Ling, Julia; Jones, Reese E.; Templeton, Jeremy Alan

    2016-05-06

    Here, in many scientific fields, empirical models are employed to facilitate computational simulations of engineering systems. For example, in fluid mechanics, empirical Reynolds stress closures enable computationally-efficient Reynolds-Averaged Navier-Stokes simulations. Likewise, in solid mechanics, constitutive relations between the stress and strain in a material are required in deformation analysis. Traditional methods for developing and tuning empirical models usually combine physical intuition with simple regression techniques on limited data sets. The rise of high-performance computing has led to a growing availability of high-fidelity simulation data, which open up the possibility of using machine learning algorithms, such as random forests or neuralmore » networks, to develop more accurate and general empirical models. A key question when using data-driven algorithms to develop these models is how domain knowledge should be incorporated into the machine learning process. This paper will specifically address physical systems that possess symmetry or invariance properties. Two different methods for teaching a machine learning model an invariance property are compared. In the first , a basis of invariant inputs is constructed, and the machine learning model is trained upon this basis, thereby embedding the invariance into the model. In the second method, the algorithm is trained on multiple transformations of the raw input data until the model learns invariance to that transformation. Results are discussed for two case studies: one in turbulence modeling and one in crystal elasticity. It is shown that in both cases embedding the invariance property into the input features yields higher performance with significantly reduced computational training costs.« less

  13. Criticality in conserved dynamical systems: experimental observation vs. exact properties.

    PubMed

    Marković, Dimitrije; Gros, Claudius; Schuelein, André

    2013-03-01

    Conserved dynamical systems are generally considered to be critical. We study a class of critical routing models, equivalent to random maps, which can be solved rigorously in the thermodynamic limit. The information flow is conserved for these routing models and governed by cyclic attractors. We consider two classes of information flow, Markovian routing without memory and vertex routing involving a one-step routing memory. Investigating the respective cycle length distributions for complete graphs, we find log corrections to power-law scaling for the mean cycle length, as a function of the number of vertices, and a sub-polynomial growth for the overall number of cycles. When observing experimentally a real-world dynamical system one normally samples stochastically its phase space. The number and the length of the attractors are then weighted by the size of their respective basins of attraction. This situation is equivalent, for theory studies, to "on the fly" generation of the dynamical transition probabilities. For the case of vertex routing models, we find in this case power law scaling for the weighted average length of attractors, for both conserved routing models. These results show that the critical dynamical systems are generically not scale-invariant but may show power-law scaling when sampled stochastically. It is hence important to distinguish between intrinsic properties of a critical dynamical system and its behavior that one would observe when randomly probing its phase space.

  14. Miscibility and dynamical properties of cellulose acetate/plasticizer systems.

    PubMed

    Bao, Cong Yu; Long, Didier R; Vergelati, Caroll

    2015-02-13

    Due to its biodegradability and renewability, a great interest has been devoted to investigating cellulose acetate in order to expand its potential applications. In addition, secondary cellulose acetate (CDA) could also be considered as a model system for strongly polar polymer system. The dynamical behavior of CDA is supposed to be governed by H-bonding and dipolar interaction network. Due to their high glass transition temperature, cellulose acetate-based systems are processed when blended with plasticizers. It is thus of utmost importance to study the miscibility and plasticizing effects of various molecules. We prepared CDA films via solvent casting method with diethyl phthalate as the plasticizer. Miscibility diagrams were established by calorimetry and thermo-mechanical (DMTA) experiments. Dynamical properties were analyzed by DMTA and broadband dielectric spectroscopy. We could identify the α-relaxation of these CDA-plasticizer systems in the frequency range from 0.06 Hz to 10(6)Hz, which allowed for describing the dynamics in the so-called Williams-Landel-Ferry/Vogel-Fulcher-Tammann regime.

  15. Upscaling of Thermal Transport Properties in Enhanced Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Johnson, S.; Hao, Y.; Chiaramonte, L.

    2010-12-01

    : Engineered Geothermal Systems (EGS) have garnered significant attention as a possible source of geographically disperse, carbon-free energy without the environmental impact of many other renewable energy sources. However, a significant barrier to the adoption of EGS is the uncertainty in whether a specific site is amenable to engineering and how fluid injection rates can affect, either through stimulation of the fracture network or through deleterious channeling of the thermal fluid, the heat extraction rate possible in a specific reservoir. Because of the uncertainties involved in determining the exact fracture network topology extant in any particular reservoir, it is desirable to have a stochastic description (distribution) of the possible heat extraction rates that could be achieved. This work provides both an approach and application of the approach for simulating several synthetic fracture networks. The approach uses a coupled geomechanics and discrete fracture network (DFN) solver coupled uni-directionally with a reservoir scale, hydro-thermal transport code, the Non-isothermal Unsaturated-Saturated Flow and Transport simulation code (NUFT), to capture the coupled hydro-thermo-mechanical behavior of these synthetic networks. Particular attention is paid to the upscaling approach used to determine effective permeability and thermal transfer coefficients that are used in the dual porosity/permeability (DKM) model employed in NUFT. This upscaling is based on a multi-scale treatment of the domain, starting with the upscaling of permeability from explicitly represented fractures in the DFN model, which considers the fracture-scale effects of fluid injection, to a finely resolved, unstructured mesh representation of the subdomain. Effective properties of this subdomain are then determined for a variety of sub-sampled discrete fracture network topologies. The result catalog of spatially correlated thermal and fluid properties are then used to populate the

  16. Topological effects on properties of multicomponent polymer systems

    NASA Astrophysics Data System (ADS)

    Singla, Swati

    Multicomponent polymer systems comprised of two or more chemically different polymer moieties provide an effective way to attain the desired properties from a limited palette of commodity polymers. Variations in macromolecular topologies often result in unique and unusual properties leading to novel applications. This dissertation addresses the effect of topology on properties of two multicomponent polymers systems: blends and polyrotaxanes. Blends of cyclic and linear polymers were compared to their topological counterparts, polyrotaxanes, in which cyclic components are threaded onto the linear polymer chains. The first part of the dissertation focuses on the synthesis and purification of cyclic polymers derived from linear (polyoxyethylene) (POE). Cyclic POEs of different cycle sizes were synthesized and then purified from their linear byproducts by inclusion complexation with alpha-cyclodextrin. Polystyrene was threaded through the resulting cycles by in situ free radical polymerization of styrene monomer in the presence of an excess of POE cycles. A bulky free radical initiator was utilized to endcap the polystyrene molecule at the two ends to prevent dethreading of cyclic moieties. In the second part of the dissertation, phase behavior, morphology and dynamics of cyclic POE and polystyrene blends were compared to linear POE and polystyrene blends. Advanced solid-state NMR techniques and differential scanning calorimetry were employed for this purpose. Cyclic POE was found to be much more miscible with polystyrene when compared to linear POE, resulting in nanometer-sized domains and significantly reduced mobilities of the cyclic POE components in the blends. The unusual behavior of cyclic POE in the blends was attributed to topological as well as end-group effects with the topological effects being predominant. Polyrotaxanes composed of polystyrene and cyclic POE components exhibited cyclic POE domain sizes similar to that of physical blends. Cyclic POE

  17. Properties of numerical experiments in chaotic dynamical systems

    NASA Astrophysics Data System (ADS)

    Yuan, Guo-Cheng

    1999-10-01

    This dissertation contains four projects that I have worked on during my graduate study at University of Maryland at College Park. These projects are all related to numerical simulations of chaotic dynamical systems. In particular, the two conjectures in Chapter 1 are inspired by the numerical discoveries in Hunt and Ott [1, 2]. In Chapter 2, statistical properties of scalar transport in chaotic flows are investigated by using numerical simulations. In Chapters 3 and 4, I take a different angle and discuss the limitations of numerical simulations; i.e. for certain ``bad'' systems numerical simulations will yield incorrect or at least unreliable results no matter how many digits of precision are used. Chapter 1 discusses the properties of optimal orbits. Given a dynamical system and a function f from the state space to the real numbers, an optimal orbit for f is an orbit over which the average of f is maximal. In this chapter we discuss some basic mathematical aspects of optimal orbits: existence, sensitivity to perturbations of f, and approximability by periodic orbits with low period. For hyperbolic systems, we conjecture that (1)for (topologically) generic smooth functions, there exists an optimal periodic orbit, and (2)the optimal average can be approximated exponentially well by averages over certain periodic orbits with increasing period. In Chapter 2 we theoretically study the power spectrum of passive scalars transported in two dimensional chaotic fluid flows. Using a wave-packet method introduced by Antonsen et al. [3] [4], we numerically investigate several model flows, and confirm that the power spectrum has the k -l- scaling predicted by Batchelor [5]. In Chapter 3 we consider a class of nonhyperbolic systems, for which there are two fixed points in an attractor having a dense trajectory; the unstable manifold of one fixed point has dimension one and the other's is two dimensional. Under the condition that there exists a direction which is more expanding

  18. Impact of fuel properties on advanced power systems

    SciTech Connect

    Sondreal, E.A.; Jones, M.L.; Hurley, J.P.; Benson, S.A.; Willson, W.G.

    1995-12-01

    Advanced coal-fired combined-cycle power systems currently in development and demonstration have the goal of increasing generating efficiency to a level approaching 50% while reducing the cost of electricity from new plants by 20% and meeting stringent standards on emissions of SO{sub x} NO{sub x} fine particulates, and air toxic metals. Achieving these benefits requires that clean hot gas be delivered to a gas turbine at a temperature approaching 1350{degrees}C, while minimizing energy losses in the gasification, combustion, heat transfer, and/or gas cleaning equipment used to generate the hot gas. Minimizing capital cost also requires that the different stages of the system be integrated as simply and compactly as possible. Second-generation technologies including integrated gasification combined cycle (IGCC), pressurized fluidized-bed combustion (PFBC), externally fired combined cycle (EFCC), and other advanced combustion systems rely on different high-temperature combinations of heat exchange, gas filtration, and sulfur capture to meet these requirements. This paper describes the various properties of lignite and brown coals.

  19. Processing and Properties of a Phenolic Composite System

    NASA Technical Reports Server (NTRS)

    Hou, Tan-Hung; Bai, J. M.; Baughman, James M.

    2006-01-01

    Phenolic resin systems generate water as a reaction by-product via condensation reactions during curing at elevated temperatures. In the fabrication of fiber reinforced phenolic resin matrix composites, volatile management is crucial in producing void-free quality laminates. A commercial vacuum-bag moldable phenolic prepreg system was selected for this study. The traditional single-vacuum-bag (SVB) process was unable to manage the volatiles effectively, resulting in inferior voidy laminates. However, a double vacuum bag (DVB) process was shown to afford superior volatile management and consistently yielded void-free quality parts. The DVB process cure cycle (temperature /pressure profiles) for the selected composite system was designed, with the vacuum pressure application point carefully selected, to avoid excessive resin squeeze-outs and achieve the net shape and target resin content in the final consolidated laminate parts. Laminate consolidation quality was characterized by optical photomicrography for the cross sections and measurements of mechanical properties. A 40% increase in short beam shear strength, 30% greater flexural strength, 10% higher tensile and 18% higher compression strengths were obtained in composite laminates fabricated by the DVB process.

  20. Understanding and Exploiting Spatial Properties of System Failures on Extreme-Scale HPC Systems

    SciTech Connect

    Rogers, James H; Maxwell, Don E

    2015-01-01

    As we approach exascale, the scientific simulations are expected to experience more interruptions due to increased system failures. Designing better HPC resilience techniques requires understanding the key characteristics of system failures on these systems. While temporal properties of system failures on HPC systems have been well-investigated, there is limited understanding about the spatial characteristics of system failures and its impact on the resilience mechanisms. Therefore, we examine the spatial characteristics and behavior of system failures. We investigate the interaction between spatial and temporal characteristics of failures and its implications for system operations and resilience mechanisms on large-scale HPC systems. We show that system failures have spatial locality at different granularity in the system; study impact of different failure-types; and investigate the correlation among different failure-types. Finally, we propose a novel scheme that exploits the spatial locality in failures to improve application and system performance. Our evaluation shows that the proposed scheme significantly improves the system performance in a dynamic and production-level HPC system.

  1. Exploring the properties of the DDO system using synthetic colors

    NASA Astrophysics Data System (ADS)

    Tripicco, Michael J.; Bell, R. A.

    1991-08-01

    The properties of the David Dunlap Observatory (DDO) system (which uses bandpasses centered at about 3450, 3800, 4180, 4250, 4500, 4850, and 5150 A, referred to as 35, 38, 41, 42, 45, 48, and 51 filters) are explored by applying synthetic colors. Using DDO colors for a sample of stars for which spectrophotometric data were reported by Gunn and Stryker (1983), the correctness of the transmission profiles of the filters was established. It is shown that the presence of MgH lines in the 48 bandpass is an important reason why cool dwarfs and giants are separated in the C(45-48) vs C(42-45) diagram. It was found that including SiH lines in the spectra improved the agreement between observed and computed C(41-45) colors for dwarfs.

  2. Analysis of properties of thrust bearing in ship propulsion system

    NASA Astrophysics Data System (ADS)

    Wu, Zhu-Xin; Liu, Zheng-Lin

    2010-06-01

    Thrust bearing is a key component of the propulsion system of a ship. It transfers the propulsive forces from the propeller to the ship’s hull, allowing the propeller to push the ship ahead. The performance of a thrust bearing pad is critical. When the thrust bearing becomes damaged, it can cause the ship to lose power and can also affect its operational safety. For this paper, the distribution of the pressure field of a thrust pad was calculated with numerical method, applying Reynolds equation. Thrust bearing properties for loads were analyzed, given variations in outlet thickness of the pad and variations between the load and the slope of the pad. It was noticed that the distribution of pressure was uneven. As a result, increases of both the outlet thickness and the slope coefficient of the pad were able to improve load bearing capability.

  3. Rheological properties of aqueous Pluronic-alginate systems containing liposomes.

    PubMed

    Grassi, G; Crevatin, A; Farra, R; Guarnieri, G; Pascotto, A; Rehimers, B; Lapasin, R; Grassi, M

    2006-09-01

    Rheological and erosion studies regarding a liposome-containing polymeric blend that is propaedeutic to its use in paving techniques in tubular organs, such as blood vessels, are reported. Attention is focused on an aqueous polymeric blend composed of Pluronic (PF127) and alginate (Protanal LF 10/60) because both polymers, when dissolved in water at a sufficiently high concentration, are subjected to different structural mechanisms, which are driven by temperature increase and addition of bivalent cations, respectively, and both result in marked viscoelastic and plastic properties. After proving the compatibility between PF127 and alginate, we show that the structural transition temperature of the blend, T(ST), can be properly modulated. In particular, we found that T(ST) for an aqueous solution of pure Pluronic 20% w/w is about 21 degrees C and that even slight reductions in polymer concentration result in considerable T(ST) decrease. The addition of salts or alginate (provided as Na-alginate) provokes a substantial decrease of T(ST) and thus the alginate concentration in the blend should not exceed 1% w/w. In addition, liposomes slow down the structural transition but do not substantially affect the rheological properties of the system in the final state at higher temperatures, thus showing that they can be added to the polymeric blend without significant effects. Finally, erosion tests show that after contact with a source of bivalent cations, the polymeric blend containing PF127 and alginate shows an erosion resistance neatly improved with respect to the simple structured Pluronic system having the same polymer concentration. As a whole, all these results constitute the basis for future potential applications of the considered polymeric blend in tubular organs such as blood vessels.

  4. 7 CFR 1955.56 - Real property located in Coastal Barrier Resources System (CBRS).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 14 2011-01-01 2011-01-01 false Real property located in Coastal Barrier Resources... Management of Property § 1955.56 Real property located in Coastal Barrier Resources System (CBRS). (a... paragraphs (b) and (c) of this section, no maintenance or repair action may be taken for property...

  5. System Report for the Optical Properties Monitor (OPM) Experiment

    NASA Technical Reports Server (NTRS)

    Hummer, L.

    2001-01-01

    This systems report describes how the Optical Properties Monitor (OPM) experiment was developed. Pertinent design parameters are discussed, along with mission information and system requirements to successfully complete the mission. Environmental testing was performed on the OPM to certify it for spaceflight. This testing included vibration, thermal vacuum, electromagnetic interference and conductance, and toxicity tests. Instrument and monitor subsystem performances, including the reflectometer, vacuum ultraviolet, total integrated scatter, atomic oxygen monitor, irradiance monitor, and molecular contamination monitor during the mission are discussed. The OPM experiment was launched aboard the Space Shuttle on mission STS-81 in January 1997 and transferred to the Mir space station. An extravehicular activity (EVA) was performed in April 1997 to attach the OPM experiment to the outside of the Mir/Shuttle Docking Module for space environment exposure. The OPM conducted in situ measurements of a number of material samples. These data may be found in the OPM Science Report. OPM was retrieved during an EVA in January 1998 and was returned to Earth on board the Space Shuttle on mission STS-89.

  6. Management Academy LANL Business Systems: Property Management, Course #31036

    SciTech Connect

    Shepherd, Michael J.; Rinke, Helen Mae; Hanson, Todd; Wolfe, Randy P.

    2016-07-08

    Los Alamos National Laboratory (LANL) is responsible for the efficient economical management of all government property in its stewardship. This training explains the role LANL managers have in managing, controlling, and disposing of government property. The Laboratory's goal is good asset management. By properly managing property across the facility, Laboratory managers can help ASM improve government property utilization and extend asset life, while reducing asset-related operating costs and expenditures.

  7. Test system accurately determines tensile properties of irradiated metals at cryogenic temperatures

    NASA Technical Reports Server (NTRS)

    Levine, P. J.; Skalka, R. J.; Vandergrift, E. F.

    1967-01-01

    Modified testing system determines tensile properties of irradiated brittle-type metals at cryogenic temperatures. The system includes a lightweight cryostat, split-screw grips, a universal joint, and a special temperature control system.

  8. Optical properties of polymer microtips investigated with workshop tomographic system

    NASA Astrophysics Data System (ADS)

    Dudek, Michał; Kujawińska, Małgorzata; Makowski, Piotr; Jaroszewicz, Leszek R.; Parat, Vincent

    2016-04-01

    We present a novel methodology for optical fiber polymer microtip manufacturing ant testing, which supports the structure optimization process through utilization of an optical diffraction tomography system based on the lateral shear digital holographic microscope. The most important functional parameter of an optical fiber microtip is the output beam distribution in the far-field region, which depends on geometrical properties and refractive index distribution within the microtip. These factors, in turn, are determined by the optical power distribution of the actinic light and the exposition time during the photopolymerization process. In order to obtain a desired light field distribution we propose to govern the manufacturing process by a hybrid opto-numerical methodology, which constitutes a convenient feedback loop for modification of the fabrication parameters. A single cycle of the proposed scheme includes numerical modeling, tomographic measurements and modifications of fabrication process. We introduced the real values of three-dimensional refractive index distribution of microtips into the finite-difference time-domain (FDTD) simulations, which leaded to controlled modification of technology parameters and finally to improvement of a functional parameter of microtips.

  9. Properties of the stimulus router system, a novel neural prosthesis.

    PubMed

    Gan, Liu Shi; Prochazka, Arthur

    2010-02-01

    Various types of neural prostheses (NPs) have been developed to restore motor function after neural injury. Surface NPs are noninvasive and inexpensive, but are often poorly selective, activating nontargeted muscles and cutaneous sensory nerves that can cause discomfort or pain. Implantable NPs are highly selective, but invasive and costly. The stimulus router system (SRS) is a novel NP consisting of fully implanted leads that "capture" and route some of the current flowing between a pair of surface electrodes to the vicinity of a target nerve. An SRS lead consists of a "pick-up" terminal that is implanted subcutaneously under one of the surface electrodes and a "delivery" terminal that is secured on or near the target nerve. We have published a preliminary report on the basic properties of the SRS [L. S. Gan , "A new means of transcutaneous coupling for neural prostheses," IEEE Trans. Biomed. Eng., vol. 54, no. 3, pp. 509-517, Mar. 2007]. Here, we further characterize the SRS and identify aspects that maximize its performance as a motor NP. The surface current needed to activate nerves with an SRS, was found to depend on the proximity of the delivery terminal(s) to the nerve, electrode configurations, contact areas of the surface electrodes and implanted terminals, and the distance between the surface anode and the delivery terminal.

  10. 25 CFR 900.54 - Should the property management system prescribe internal controls?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... System Standards § 900.54 Should the property management system prescribe internal controls? Yes. Effective internal controls should include procedures: (a) For the conduct of periodic inventories; (b) To... 25 Indians 2 2011-04-01 2011-04-01 false Should the property management system prescribe...

  11. 25 CFR 900.54 - Should the property management system prescribe internal controls?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... System Standards § 900.54 Should the property management system prescribe internal controls? Yes. Effective internal controls should include procedures: (a) For the conduct of periodic inventories; (b) To... 25 Indians 2 2010-04-01 2010-04-01 false Should the property management system prescribe...

  12. Dust in the Solar System - Properties and Origins

    NASA Technical Reports Server (NTRS)

    Messenger, Scott; Keller, Lindsay; Nakamura-Messenger, Keiko

    2013-01-01

    include both amorphous and crystalline silicates. The organic matter in these samples also exhibits highly anomalous H, C, and N isotopic compositions that are consistent with formation in low temperature environments at the outermost regions of the solar nebula or presolar cold molecular cloud. The scientific frontiers for these samples include working toward a better understanding of the origins of the solar system amorphous and crystalline grains in IDPs and the very challenging task of determining the chemical composition of sub-micron organic grains. Laboratory studies of ancient and present-day dust in the Solar System thus reveal in exquisite detail the chemistry, mineralogy and isotopic properties of materials that derive from a range of astrophysical environments. These studies are an important complement to astronomical observations that help to place the laboratory observations into broader context.

  13. 32 CFR 34.23 - Property management system.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the Federal Government) and cost. (6) Information from which one can calculate the percentage of Federal participation in the cost of the property (not applicable to property furnished by the Federal... current fair market value where a recipient compensates the Federal Government for its share....

  14. PHOTOMETRIC PROPERTIES OF THE M33 STAR CLUSTER SYSTEM

    SciTech Connect

    San Roman, Izaskun; Sarajedini, Ata; Aparicio, Antonio E-mail: ata@astro.ufl.ed

    2010-09-10

    We present a catalog of 2990 extended sources in a 1{sup 0} x 1{sup 0} area centered on M33 using the MegaCam camera on the 3.6 m Canada-France-Hawaii Telescope. The catalog includes 599 new candidate stellar clusters, 204 previously confirmed clusters, 1969 likely background galaxies, and 218 unknown extended objects. We present ugriz integrated magnitudes of the candidates and confirmed star clusters (SCs) as well as the full width at half maximum, ellipticity, and stellarity. Based on the properties of the confirmed SCs, we select a sub-sample of highly probable clusters composed of 246 objects. The integrated photometry of the complete cluster catalog reveals a wide range of colors of -0.4 < (g - r) < 1.5 and -1.0 < (r - i) < 1.0 with no obvious cluster subpopulations. Comparisons with models of simple stellar populations suggest a large range of ages some as old as {approx}10 Gyr. In addition, we find a sequence in the color-color diagrams that deviates from the expected direction of evolution. This feature could be associated with very young clusters (<10{sup 7} yr) possessing significant nebular emission. Analysis of the radial density distribution suggests that the cluster system of M33 has suffered from significant depletion possibly due to interactions with M31. We also detect a gap in the cluster distribution in the color-color diagram at (g - r) {approx_equal} 0.3 and (u - g) {approx_equal} 0.8. This gap could be interpreted as an evolutionary effect. This complete catalog provides promising targets for deep photometry and high-resolution spectroscopy to study the structure and star formation history of M33.

  15. Organic cotton systems improved soil properties vis-a-vis the modern systems

    NASA Astrophysics Data System (ADS)

    Blaise, D.; Venugopalan, M. V.; Singh, J. V.; Narkhedkar, N. G.; Velmourougane, K.

    2012-04-01

    India is the largest cotton growing country in the world. Traditionally, cotton in India was grown with minimal inputs and resources available on farm were put to efficient use. Advent of hybrids and Bt cotton revolutionized cotton production in the country and lead to heavy reliance on external inputs. However, there is a growing awareness of the detrimental effects of excessive use of pesticides and fertilizers. This is leading to growing interest in organic cultivation of crops. An organic system (OS) was compared with the modern systems (MS) for changes in the soil physical, chemical and biological properties in field experiments conducted both on station and farmers fields in Maharashtra, India on rain dependent cotton grown on Vertisols. Soil samples of the organic plots had significantly greater C content than the MS plots relying on mineral fertilizers and pesticides. Similarly, other nutrients were also greater in the OS than the MS across locations. Most of the increases were noticed in the top 30 cm of the soil profile. Interestingly, enrichment of the soil at lower depths was noticed in the OS which could be due to the surface creep of soils through the cracks in the Vertisols. With regard to the physical properties, water-stable aggregates and mean weight diameter in the MS were significantly lesser than the OS. Differences were restricted to the top 20 cm. Soil biological properties of the two systems were compared through the enzyme assays such as the dehydrogenase, glucosidase, phosphatase, sulfatase periodically during the crop growing season. All the enzyme assays indicated greater activities in the OS than the MS. Further, microfauna (nematodes) monitored indicated less of plant parasitic nematodes in the OS than the MS. Excessive tillage followed in the MS did bring about a reduction in the nematode numbers. But the systems had more parasitic nematodes.

  16. Momentum and spin transport properties of spin polarized Fermi systems

    NASA Astrophysics Data System (ADS)

    Wei, Lijuan

    We carried out experiments on a spin polarized 3He- 4He mixture with 3He concentration x 3 = 6.26 x 10-4, and on pure 3He liquid. Spin polarization affects the transport properties of these Fermi systems. The effect on momentum transport was studied by using a vibrating-wire viscometer to measure viscosity of the 3He-4He mixture over the temperature range 6.09 mK--100 mK in 7.96 T and 1.00 T magnetic fields. A large viscosity increase was observed upon application of the 7.96 T magnetic field for temperature T < TF(TF = 19.5 mK is the Fermi temperature). The observed viscosity is in very good agreement with theoretical calculations for a dilute Fermi gas by Jeon and Mullin [1988, 1989] and Mullin and Jeon [1992]. The polarization effect on spin transport was investigated by measuring the transverse diffusion coefficient D ⊥ in pure 3He liquid at saturated vapor pressure and at 15.85 bar over the temperature range 4.5 mK--159 mK in a 7.96 T magnetic field. We used a pulsed NMR spin echo technique in a field gradient of 16.0 G/cm to do the measurements and fits to the Leggett equations [1970] to obtain D⊥. For T < 20 mK, we found D⊥ is less than measured in earlier experiments at lower magnetic fields. D⊥ does not increase with decreasing temperature as 1/T2, but appears to approach a constant as T → 0 while it is expected that the longitudinal spin diffusion coefficient D∥ ∝ 1/ T2. This is called spin diffusion anisotropy and it was observed for the first time in our 3He liquid experiments. The anisotropy temperature we determined for 3He liquid was Ta = 16.4 +/- 2.2 mK at saturated vapor pressure and in a 7.96 T magnetic field. The transverse spin diffusion in 3 He results agree qualitatively with theories proposed by Meyerovich and Musaeflan [1992, 1994]. They also agree qualitatively with theories proposed by Golosov and Ruckenstein [1995, 1998] by extrapolation of the dilute theory to a strongly interacting system.

  17. Electronic contributions to linear and nonlinear electric properties in fullerene-based molecular systems

    NASA Astrophysics Data System (ADS)

    Skwara, B.; Loboda, O.; Avramopoulos, A.; Luis, J.-M.; Reis, H.; Papadopoulos, M. G.

    2012-12-01

    Recent studies of the linear and nonlinear electric properties of various fullerene-based subsystems are reviewed. The electric properties of derivatives of C60 fullerene with carbazole, benzothiazole, benzothiazole-triphenyloamine and free-base porphyrin substituents at different levels of theory are summarized. In addition, the electronic and vibrational electric properties of endohedral Sc2@C72 system are reported.

  18. 7 CFR 1955.56 - Real property located in Coastal Barrier Resources System (CBRS).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE SERVICE, RURAL UTILITIES SERVICE, AND FARM SERVICE AGENCY, DEPARTMENT OF AGRICULTURE (CONTINUED) PROGRAM REGULATIONS (CONTINUED) PROPERTY MANAGEMENT Management of Property § 1955.56 Real property located in Coastal Barrier Resources System (CBRS)....

  19. Properties of hybrid resin composite systems containing prepolymerized filler particles.

    PubMed

    Blackham, Jason T; Vandewalle, Kraig S; Lien, Wen

    2009-01-01

    This study compared the properties of newer hybrid resin composites with prepolymerized-filler particles to traditional hybrids and a microfill composite. The following properties were examined per composite: diametral tensile strength, flexural strength/modulus, Knoop microhardness and polymerization shrinkage. Physical properties were determined for each Jason T Blackham, DMD, USAF, General Dentistry, Tyndall composite group (n = 8), showing significant differences between groups per property (p < 0.001). In general, the traditional hybrid composites (Z250, Esthet-X) had higher strength, composites containing pre-polymerized fillers (Gradia Direct Posterior, Premise) performed more moderately and the microfill composite (Durafill VS) had lower strength. Premise and Durafill VS had the lowest polymerization shrinkage.

  20. Property.

    ERIC Educational Resources Information Center

    Piele, Philip K.

    Several court cases involving acquisition, use, and disposal of property by institutions of higher education are briefly summarized in this chapter. Cases discussed touch on such topics as municipal annexation of university property; repurchase of properties temporarily allocated to faculty members; implications of zoning laws and zoning board…

  1. ORBITAL DEPENDENCE OF GALAXY PROPERTIES IN SATELLITE SYSTEMS OF GALAXIES

    SciTech Connect

    Hwang, Ho Seong; Park, Changbom E-mail: cbp@kias.re.k

    2010-09-01

    We study the dependence of satellite galaxy properties on the distance to the host galaxy and the orbital motion (prograde and retrograde orbits) using the Sloan Digital Sky Survey (SDSS) data. From SDSS Data Release 7, we find 3515 isolated satellite systems of galaxies at z < 0.03 that contain 8904 satellite galaxies. Using this sample, we construct a catalog of 635 satellites associated with 215 host galaxies whose spin directions are determined by our inspection of the SDSS color images and/or by spectroscopic observations in the literature. We divide satellite galaxies into prograde and retrograde orbit subsamples depending on their orbital motion with respect to the spin direction of the host. We find that the number of galaxies in prograde orbit is nearly equal to that of retrograde orbit galaxies: the fraction of satellites in prograde orbit is 50% {+-} 2%. The velocity distribution of satellites with respect to their hosts is found to be almost symmetric: the median bulk rotation of satellites is -1 {+-} 8 km s{sup -1}. It is found that the radial distribution of early-type satellites in prograde orbit is strongly concentrated toward the host while that of retrograde ones shows much less concentration. We also find the orbital speed of late-type satellites in prograde orbit increases as the projected distance to the host (R) decreases while the speed decreases for those in retrograde orbit. At R less than 0.1 times the host virial radius (R < 0.1r{sub vir,host}), the orbital speed decreases in both prograde and retrograde orbit cases. Prograde satellites are on average fainter than retrograde satellites for both early and late morphological types. The u - r color becomes redder as R decreases for both prograde and retrograde orbit late-type satellites. The differences between prograde and retrograde orbit satellite galaxies may be attributed to their different origin or the different strength of physical processes that they have experienced through

  2. Mechanical Properties of Normal and Diseased Cerebrovascular System

    PubMed Central

    Ebrahimi, Ali P.

    2009-01-01

    Background: Blood vessel mechanics has traditionally been of interest to researchers and clinicians. Changes in mechanical properties of arteries have been associated with various diseases. Objective: To provide a comprehensive review directed towards understanding the basic biomechanical properties of cerebral arteries under normal and diseased conditions. Methods: Literature review supplemented by personal knowledge. Results: The mechanical properties of vascular tissue may depend on several factors including macromolecular volume fraction, molecular orientation, and volume or number of cells such as smooth muscle cells. Mechanical properties of a blood vessel have been characterized using different methods such as in vitro tensile testing, non-invasive ultrasound examination, and mathematical models. Experiments are complicated by the variation in properties and content of materials that make up the vessel wall and more challenging as the size of the vessel of interest decreases. Therapeutic interventions aiming to alter the mechanical response are either pharmaceutical: including calcium channel blockers, angiotensin converting enzyme inhibitors (ACEI), angiotensin receptor blockers (ARB), and β-blockers; or, mechanical interventions such as angioplasty, stent placement, mechanical thrombectomy, or embolization procedures. Conclusion: It is apparent from the literature that macromolecular and cellular mechanics of blood vessels are not fully understood. Therefore, further studies are necessary to better understand contribution of these mechanisms to the overall mechanics of the vascular tissue. PMID:22518247

  3. Magnetic properties driven by local structure in quasi-1D Ising chain system cobaltate system

    NASA Astrophysics Data System (ADS)

    Kim, Bongjae; Kim, Beom Hyun; Kim, Kyoo; Choi, Hong Chul; Park, Sang-Yeon; Jeong, Y.-H.; Min, B. I.

    2012-02-01

    Using ab-initio band structure method and the microscopic model calculation, the origins of the large orbital magnetic moment and unique magnetic anisotropy in the quasi-1D magnetic cobaltate, α-CoV2O6, is investigated. Unique crystal electric field effect in α-CoV2O6 is combined with the strong spin-orbit coupling, results in intriguing magnetic properties of the system. Based on the estimated strengths of the intra- and the inter-chain exchange interaction, experimentally found 1/3 magnetization plateau in the MH curve can be attributed to spin-flop mechanism. Origin of the reduced magnetic entropy behavior is found to be the strong uniaxial magnetic anisotropy in the quasi-1D Ising chain system.

  4. Protocol dependence of mechanical properties in granular systems.

    PubMed

    Inagaki, S; Otsuki, M; Sasa, S

    2011-11-01

    We study the protocol dependence of the mechanical properties of granular media by means of computer simulations. We control a protocol of realizing disk packings in a systematic manner. In 2D, by keeping material properties of the constituents identical, we carry out compaction with various strain rates. The disk packings exhibit the strain rate dependence of the critical packing fraction above which the pressure becomes non-zero. The observed behavior contrasts with the well-studied jamming transitions for frictionless disk packings. We also observe that the elastic moduli of the disk packings depend on the strain rate logarithmically. Our results suggest that there exists a time-dependent state variable to describe macroscopic material properties of disk packings, which depend on its protocol.

  5. Augmentation of the In Vivo Elastic Properties Measurement System to Include Bulk Properties

    DTIC Science & Technology

    2014-09-30

    estimates based on measured displacement magnitudes. APPROACH The bulk properties measurement methods are intended to run concurrently with the...to better understand biomechanics of sound reception and production in cetaceans, and 2) to understand and hopefully mitigate any harmful effects of

  6. Electronic properties of crystalline fluorides of a cubic crystal system

    NASA Astrophysics Data System (ADS)

    Eremin, I. E.; Eremin, E. L.; Demchuk, V. A.; Moiseenko, V. G.

    2014-01-01

    The possibility of effective mathematical modeling of polarization characteristics of crystalline dielectrics is considered. It is shown that the generation of frequency dielectric spectra of the substances under consideration, which equivalent to their physically measured properties, gives the objective possibility of mediated visualization of their electron-atomic structure.

  7. Dielectric Properties of PMN-PZ-PT System

    DTIC Science & Technology

    2007-11-02

    acetylacetone. 0.1Pb(Mg1/3Nb2/3)O3-0.9Pb(ZrxTi(1-x))O3 thin films were deposited on Pt-coated substrate by spin - coating and crystallized at 700 deg C in air. And then their dielectric properties were investigated.

  8. Structure-Property Characterization of the Crinkle-Leaf Peach Wood Phenotype: A Future Model System for Wood Properties Research?

    NASA Astrophysics Data System (ADS)

    Wiedenhoeft, Alex C.; Arévalo, Rafael; Ledbetter, Craig; Jakes, Joseph E.

    2016-09-01

    Nearly 400 million years of evolution and field-testing by the natural world has given humans thousands of wood types, each with unique structure-property relationships to study, exploit, and ideally, to manipulate, but the slow growth of trees makes them a recalcitrant experimental system. Variations in wood features of two genotypes of peach ( Prunus persica L.) trees, wild-type and crinkle-leaf, were examined to elucidate the nature of weak wood in crinkle-leaf trees. Crinkle-leaf is a naturally-occurring mutation in which wood strength is altered in conjunction with an easily observed `crinkling' of the leaves' surface. Trees from three vigor classes (low growth rate, average growth rate, and high growth rate) of each genotype were sampled. No meaningful tendency of dissimilarities among the different vigor classes was found, nor any pattern in features in a genotype-by-vigor analysis. Wild-type trees exhibited longer vessels and fibers, wider rays, and slightly higher specific gravity. Neither cell wall mechanical properties measured with nanoindentation nor cell wall histochemical properties were statistically or observably different between crinkle-leaf and wild-type wood. The crinkle-leaf mutant has the potential to be a useful model system for wood properties investigation and manipulation if it can serve as a field-observable vegetative marker for altered wood properties.

  9. Property.

    ERIC Educational Resources Information Center

    Goldblatt, Steven M.; Piele, Philip K.

    This chapter reviews 1982 cases related to school property. Cases involving citizen efforts to overturn school board decisions to close schools dominate the property chapter, and courts continue to uphold school board authority to close schools, transfer students, and sell or lease the buildings. Ten cases involving detachment and attachment of…

  10. Property.

    ERIC Educational Resources Information Center

    Bickel, Robert D.; Zeller, Trisha A.

    A number of cases related to property issues involving institutions of higher education are examined in this chapter. Cases discussed touch on such topics as funding for property and equipment acquisition; opposition to building construction or demolition; zoning issues; building construction and equipment contracts; and lease agreements. Current…

  11. Property.

    ERIC Educational Resources Information Center

    Piele, Philip K.; Johnson, Margaret M.

    This chapter deals with 1981 cases involving disputes over property. Cases involving the detachment and attachment of land continue to dominate the property chapter with 11 cases reported, the same number summarized in last year's chapter. One case involving school board referenda raised the interesting question of whether or not a state could…

  12. Property.

    ERIC Educational Resources Information Center

    Piele, Philip K.

    Chapter 7 of a book on school law, this chapter deals with 1979 cases involving disputes over property. Cases involving taxpayer attempts to prevent the construction of school buildings dominate this year's property chapter, as they did last year's. Yet, paradoxically, there is also a significant increase in cases in which taxpayers tried to…

  13. Environmental Containment Property Estimation Using QSARs in an Expert System

    DTIC Science & Technology

    1993-01-15

    measure of the polar nature. After the regression equations were chosen the final calculations of the Analysis of Variance table and the graphs were...area. J. Phys. Chem., 1972. 76: p. 2754-2759. 14. Amidon, G.L., S.H. Yalkowsky, and S.Leung, Solubility of Nonelectroytes in Polar Solvents II...X)np is the index for the non- polar molecule and X is the index for the original molecule. Choosing the Properties After the MCIs have been

  14. Shocks in 2D Yukawa systems : thermodynamics and kinetic properties

    NASA Astrophysics Data System (ADS)

    Murillo, Michael S.; Marciante, Mathieu

    2016-10-01

    The study of shock propagation has become a common way to obtain statistical information on a medium, as one can relate properties of the undisturbed medium to the shock dynamics through the Rankine-Hugoniot relations. However, theoretical investigations of shock dynamics are often done through idealized fluid models, which neglect kinetic properties. In this poster we study the propagation of shock waves in plasmas at the particle level, using molecular dynamics simulations to model the propagation of stationary shock waves in a two-dimensional Yukawa plasma. Stationary shocks are generated by a piston moving at constant speed, and macroscopic thermodynamic quantities such as temperature and pressure are computed from statistical averages. This theoretical investigation comprises two parts. First, we present the thermodynamic equilibrium properties of Yukawa plasmas under shock dynamics. Next, we focus on the influence of the kinetic aspects of the plasma, showing how transport coefficients of fluid models are related to the microscopic dynamics in phase-space and apply it to the Yukawa plasma case. Contract DE-AC52-06NA25396.

  15. System and method to determine thermophysical properties of a multi-component gas

    DOEpatents

    Morrow, Thomas B.; Behring, II, Kendricks A.

    2003-08-05

    A system and method to characterize natural gas hydrocarbons using a single inferential property, such as standard sound speed, when the concentrations of the diluent gases (e.g., carbon dioxide and nitrogen) are known. The system to determine a thermophysical property of a gas having a first plurality of components comprises a sound velocity measurement device, a concentration measurement device, and a processor to determine a thermophysical property as a function of a correlation between the thermophysical property, the speed of sound, and the concentration measurements, wherein the number of concentration measurements is less than the number of components in the gas. The method includes the steps of determining the speed of sound in the gas, determining a plurality of gas component concentrations in the gas, and determining the thermophysical property as a function of a correlation between the thermophysical property, the speed of sound, and the plurality of concentrations.

  16. Thermodynamic properties of some metal oxide-zirconia systems

    NASA Technical Reports Server (NTRS)

    Jacobson, Nathan S.

    1989-01-01

    Metal oxide-zirconia systems are a potential class of materials for use as structural materials at temperatures above 1900 K. These materials must have no destructive phase changes and low vapor pressures. Both alkaline earth oxide (MgO, CaO, SrO, and BaO)-zirconia and some rare earth oxide (Y2O3, Sc2O3, La2O3, CeO2, Sm2O3, Gd2O3, Yb2O3, Dy2O3, Ho2O3, and Er2O3)-zirconia system are examined. For each system, the phase diagram is discussed and the vapor pressure for each vapor species is calculated via a free energy minimization procedure. The available thermodynamic literature on each system is also surveyed. Some of the systems look promising for high temperature structural materials.

  17. Common computational properties found in natural sensory systems

    NASA Astrophysics Data System (ADS)

    Brooks, Geoffrey

    2009-05-01

    Throughout the animal kingdom there are many existing sensory systems with capabilities desired by the human designers of new sensory and computational systems. There are a few basic design principles constantly observed among these natural mechano-, chemo-, and photo-sensory systems, principles that have been proven by the test of time. Such principles include non-uniform sampling and processing, topological computing, contrast enhancement by localized signal inhibition, graded localized signal processing, spiked signal transmission, and coarse coding, which is the computational transformation of raw data using broadly overlapping filters. These principles are outlined here with references to natural biological sensory systems as well as successful biomimetic sensory systems exploiting these natural design concepts.

  18. Vibrational properties of quasiregular systems with mirror symmetry

    NASA Astrophysics Data System (ADS)

    Montalbán, A.; Velasco, V. R.; Tutor, J.; Fernández-Velicia, F. J.

    2005-12-01

    We have studied the vibrational frequencies and atom displacements of one-dimensional systems formed by combinations of quasiregular stackings having mirror symmetry. The materials are described by nearest-neighbor force constants and the corresponding atom masses. Fibonacci, Thue-Morse and Rudin-Shapiro sequences are considered. These systems exhibit differences in the frequency spectrum as compared to the original systems with no mirror symmetry. Localized modes are found in the wide primary gaps and near the band edges of the Fibonacci structures. In the Rudin-Shapiro structures localized modes near the band edges are also found whereas in the Thue-Morse structures no such features are found. Besides this a selective confinement of the atom displacements in one of the sequences forming the total system is found for different frequency ranges in all the systems studied.

  19. Definition of Tire Properties Required for Landing System Analysis

    NASA Technical Reports Server (NTRS)

    Clark, S. K.; Dodge, R. N.; Luchini, J. R.

    1978-01-01

    The data bank constructed provided two basic advantages for the user of aircraft tire information. First, computerization of the data bank allowed mechanical property data to be stored, corrected, updated, and revised quickly and easily as more reliable tests and measurements were carried out. Secondly, the format of the book which can be printed from the computerized data bank can be easily adjusted to suit the needs of the users without the great expense normally associated with reprinting and editing books set by ordinary typography.

  20. Estimating coupling directions in the cardiorespiratory system using recurrence properties.

    PubMed

    Marwan, Norbert; Zou, Yong; Wessel, Niels; Riedl, Maik; Kurths, Jürgen

    2013-08-28

    The asymmetry of coupling between complex systems can be studied by conditional probabilities of recurrence, which can be estimated by joint recurrence plots. This approach is applied for the first time on experimental data: time series of the human cardiorespiratory system in order to investigate the couplings between heart rate, mean arterial blood pressure and respiration. We find that the respiratory system couples towards the heart rate, and the heart rate towards the mean arterial blood pressure. However, our analysis could not detect a clear coupling direction between the mean arterial blood pressure and respiration.

  1. Property Accounting for Local and State School Systems. State Educational Records and Reports Series--Handbook III.

    ERIC Educational Resources Information Center

    Reason, Paul L.; Tankard, George G., Jr.

    This handbook serves as a basic guide to property accounting for local and state school systems in the U.S. Information and guidelines are presented regarding--(1) classification of property accounts, (2) definitions of property accounts, (3) measures of school property, (4) supplies and equipment, (5) individual property records, and (6) summary…

  2. Flight control systems properties and problems, volume 1

    NASA Technical Reports Server (NTRS)

    Mcruer, D. T.; Johnston, D. E.

    1975-01-01

    This volume contains a delineation of fundamental and mechanization-specific flight control characteristics and problems gleaned from many sources and spanning a period of over two decades. It is organized to present and discuss first some fundamental, generic problems of closed-loop flight control systems involving numerator characteristics (quadratic dipoles, non-minimum phase roots, and intentionally introduced zeros). Next the principal elements of the largely mechanical primary flight control system are reviewed with particular emphasis on the influence of nonlinearities. The characteristics and problems of augmentation (damping, stability, and feel) system mechanizations are then dealt with. The particular idiosyncracies of automatic control actuation and command augmentation schemes are stressed, because they constitute the major interfaces with the primary flight control system and an often highly variable vehicle response.

  3. Intellectual property education exemplified by the patents on the CRISPR/Cas9 system.

    PubMed

    Fan, Xiangyu; Liao, Guojian; Xie, Jianping

    2014-12-01

    With the accelerated globalization of the world economies, the role of intellectual property in the the competition is increasingly important. The universities are important base to instill the intellectual property awareness to the young generation. However, current model of intellectual property education cannot meet the needs of undergraduates. In this paper, we take the first patent issued for CRISPR/Cas9 system as a teaching example, and together with personal teaching experience in biomedicine related intellectual property, we propose a new way for intellectual property education which consists of two stages: enlightenment stage and in-depth training stage. In the former stage, we integrate the intellectual property education with the basic major courses. In the latter stage, students are encouraged to devote into intellectual property related career. This model can somehow solve the the current shortage of qualified teachers for biotechnology related intellectual property education and will facilitate the popularization of intellectual property in college students. Since genetics plays a pivotal role in biomedicine, this effort is illustrated by the novel genome editing technology based on the CRISPR/Cas9 system, which is one hotspot of recent studies. The trajectory of CRISPR/Cas9 from basic microbial genetics discovery to major tools for genome editing exeplified the essence of biomedicine related intellectual property education.

  4. A Variational Property of the Velocity Distribution in a System of Material Particles

    ERIC Educational Resources Information Center

    Siboni, S.

    2009-01-01

    A simple variational property concerning the velocity distribution of a set of point particles is illustrated. This property provides a full characterization of the velocity distribution which minimizes the kinetic energy of the system for prescribed values of linear and angular momentum. Such a characterization is applied to discuss the kinetic…

  5. Impacts of an integrated crop-livestock system on soil properties to enhance precipitation capture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cropping/Livestock systems alter soil properties that are important in enhancing capture of precipitation by developing and maintaining water infiltration and storage. In this paper we will relate soil hydraulic conductivity and other physical properties on managed Old World Bluestem grassland, whea...

  6. Markov property and strong additivity of von Neumann entropy for graded quantum systems

    SciTech Connect

    Moriya, Hajime

    2006-03-15

    The quantum Markov property is equivalent to the strong additivity of von Neumann entropy for graded quantum systems. The additivity of von Neumann entropy for bipartite graded systems implies the statistical independence of states. However, the structure of Markov states for graded systems is different from that for tensor-product systems which have trivial grading. For three-composed graded systems we have U(1)-gauge invariant Markov states whose restriction to the marginal pair of subsystems is nonseparable.

  7. A Regenerable VOC Control System (RVCS) for Characterizing Properties of Sorbents Used in Separation Technologies

    NASA Technical Reports Server (NTRS)

    Nolek, Sara D.; Monje, Oscar A.

    2010-01-01

    This slide presentation reviews the design, method of operation, and testing of a regenerable Volatile Organic Compound (VOC) control system that characterizes properties of sorbents used in separation technologies.

  8. The analysis on optical property for stereo vision measurement system

    NASA Astrophysics Data System (ADS)

    Liu, Zong-ming; Ye, Dong; Zhang, Yu; Lu, Shan; Cao, Shu-qing

    2016-01-01

    In the relative measurement for the space non-cooperative target, the analysis to the optical property of the target is one of premises of the sensor design. The article is targeted on GEO satellites. From the perspective of photometry and based on the blackbody radiation law, we analyze the visible light energy of the sun outside the atmosphere, and consider the impact of satellite thermal control multilayer, model the luminosity feature related to the solar incident angle and the sensor observing angle. Finally we get the equivalent visual magnitude of the target satellite at the pupil of the camera. Our research could effectively direct the design and development of the visible relative measurement sensor.

  9. Thermal properties of composite materials: a complex systems approximation

    NASA Astrophysics Data System (ADS)

    Carrillo, J. L.; Bonilla, Beatriz; Reyes, J. J.; Dossetti, Victor

    We propose an effective media approximation to describe the thermal diffusivity of composite samples made of polyester resin and magnetite inclusions. By means of photoacoustic spectroscopy, the thermal diffusivity of the samples were experimentally measured. The volume fraction of the inclusions was systematically varied in order to study the changes in the effective thermal diffusivity of the composites. For some samples, a static magnetic field was applied during the polymerization process, resulting in anisotropic inclusion distributions. Our results show a significant difference in the thermal properties of the anisotropic samples, compared to the isotropic randomly distributed. We correlate some measures of the complexity of the inclusion structure with the observed thermal response through a multifractal analysis. In this way, we are able to describe, and at some extent predict, the behavior of the thermal diffusivity in terms of the lacunarity and other measures of the complexity of these samples Partial Financial Support by CONACyT México and VIEP-BUAP.

  10. Adaptive mechanical properties of topologically interlocking material systems

    NASA Astrophysics Data System (ADS)

    Khandelwal, S.; Siegmund, T.; Cipra, R. J.; Bolton, J. S.

    2015-04-01

    Topologically interlocked material systems are two-dimensional granular crystals created as ordered and adhesion-less assemblies of unit elements of the shape of platonic solids. The assembly resists transverse forces due to the interlocking geometric arrangement of the unit elements. Topologically interlocked material systems yet require an external constraint to provide resistance under the action of external load. Past work considered fixed and passive constraints only. The objective of the present study is to consider active and adaptive external constraints with the goal to achieve variable stiffness and energy absorption characteristics of the topologically interlocked material system through an active control of the in-plane constraint conditions. Experiments and corresponding model analysis are used to demonstrate control of system stiffness over a wide range, including negative stiffness, and energy absorption characteristics. The adaptive characteristics of the topologically interlocked material system are shown to solve conflicting requirements of simultaneously providing energy absorption while keeping loads controlled. Potential applications can be envisioned in smart structure enhanced response characteristics as desired in shock absorption, protective packaging and catching mechanisms.

  11. Properties and performance of grazing-incidence mirror systems

    NASA Astrophysics Data System (ADS)

    Aspnes, D. E.; Kelso, S. M.

    1982-04-01

    We investigate the performance of, and the origin of aberrations in, beam lines based on simple and the recently proposed CARSA mirror elements. New results include the identification of the sums of off-grazing angles and their squares as figures of merit for total reflectance and scattering losses in near-grazing-incidence systems, and the discovery that the usual image distortions and aberrations previously associated with simple elements can essentially be eliminated with pairs of elliptical mirrors having a common rotational symmetry axis. Slit throughput efficiencies and sensitivities to system stability are calculated for both horizontal and vertical dispersion for several representative beam lines using a ray-tracing program developed for CARSA systems. We find that high-resolution operation is possible with no entrance slit for CARSA combinations.

  12. System and methods to determine and monitor changes in microstructural properties

    DOEpatents

    Turner, Joseph A

    2014-11-18

    A system and methods with which changes in microstructure properties such as grain size, grain elongation, texture, and porosity of materials can be determined and monitored over time to assess conditions such as stress and defects. An example system includes a number of ultrasonic transducers configured to transmit ultrasonic waves towards a target region on a specimen, a voltage source configured to excite the first and second ultrasonic transducers, and a processor configured to determine one or more properties of the specimen.

  13. Investigations regarding the evaluation of specific intellectual property production risks within Quality Management System

    NASA Astrophysics Data System (ADS)

    Pakocs, R.; Lupulescu, N. B.

    2016-11-01

    This paper is a theoretical research concerning methods for risk assessment of specific intellectual property production risks that are identified in the product achievement stage within the Quality Management System. In order to realize this, we will start by identifying the specific intellectual property production risks and by proposing some new calculating formulas for minimalizing their negative effects. The theoretical model proposed assessment of specific intellectual property production risks, will be realized based on 3 hypothetical situations. This study intends to reduce the intellectual property risks identified in the production process of commercial societies that have an industrial profile.

  14. Viscoelastic Properties of Polymer Systems From Dissipative Particle Dynamics Simulations

    DTIC Science & Technology

    2008-11-01

    interacting particles, and t is the time step. Español and Warren (1995) showed that the system samples the canonical ensemble and obeys the...Sloan, J.; Napadensky, E.; Beyer, R.; Snyder, J.; Chung, P. W.; McKnight, S. 25th Army Science Conference, 2006. Español , P.; Warren, P. B

  15. An ultrasonic system for determining papaya physiological properties

    NASA Astrophysics Data System (ADS)

    Ibrahim, Sallehuddin; Ramli, Azlin; Yunus, Mohd Amri Md

    2015-05-01

    There is an increasing need for high quality fruit. As such it is important to have a fast, accurate and reliable method for measuring and monitoring the quality of fruit from the field to the consumer. This paper presents an investigation on the use of a non-destructive ultrasonic system which can be used to measure the quality of papaya.

  16. Computing physical properties with quantum Monte Carlo methods with statistical fluctuations independent of system size.

    PubMed

    Assaraf, Roland

    2014-12-01

    We show that the recently proposed correlated sampling without reweighting procedure extends the locality (asymptotic independence of the system size) of a physical property to the statistical fluctuations of its estimator. This makes the approach potentially vastly more efficient for computing space-localized properties in large systems compared with standard correlated methods. A proof is given for a large collection of noninteracting fragments. Calculations on hydrogen chains suggest that this behavior holds not only for systems displaying short-range correlations, but also for systems with long-range correlations.

  17. AC Breakdown Properties of Bamboo-Ice Composite System at Cryogenic Region

    NASA Astrophysics Data System (ADS)

    Shiji, Yuhei; Muramoto, Yuji; Shimizu, Noriyuki

    In recent years biomaterials attract attention in various fields to solve environmental problems. Bamboo is naturally decomposed and characterized by its excellent elasticity, split and water absorption property. We consider that bamboo-ice composite system can be used as a substitute of GFRP (Glass Fiber Reinforced Plastics), which is not decomposed, in electrical insulation system at cryogenic region. In this paper we will report the effect of water absorption on ac breakdown of bamboo-ice composite system in liquid nitrogen. Ac breakdown properties of bamboo-ice composite system depend on water absorption and structure of bamboo.

  18. The right of women in property sharing in Bangladesh: Can the islamic inheritance system eliminate discrimination?

    PubMed

    Khan, Issa; Abdullah, Md Faruk; Rahman, Noor Naemah Abdul; Nor, Mohd Roslan Bin Mohd; Yusoff, Mohd Yakub Zulkifli Bin Mohd

    2016-01-01

    This study seeks to discover the best solution for women's property sharing between Islamic and current social practices in Bangladesh. A qualitative method has been adopted to achieve this goal. It is found that the majority of the women are marginalised from their property in the social practice. On the other hand, in the Islamic solution, the property is fixed for all classes of women and is based on a property sharing system called fara'id that takes into account the roles and responsibilities of man and woman in the society. Men are responsible for providing maintenance to their wives and children. Men in Islamic society should bear expenditure related to marriage. The research concludes that the Islamic solution is fair and ensures just property sharing rights for women. It suggests that the Islamic solution for property sharing should be implemented to empower women in Bangladesh.

  19. Property.

    ERIC Educational Resources Information Center

    Piele, Philip K.

    Numerous cases in this year's chapter dealt with the same topics of previous years--contracts and bids for building construction, and detachment and annexation of a portion of a school district. The courts continued to attribute board discretionary authority to school boards in school property matters. Intergovernmental disputes over ownership or…

  20. Property.

    ERIC Educational Resources Information Center

    Piele, Philip K.; Forsberg, James R.

    This chapter summarizes and analyze all state supreme court and federal court decisions as well as other significant court decisions involving school property. The cases discussed are generally limited to those decided during 1974 and reported in the General Digest on or before March 1, 1975. In their discussion, the authors attempt to integrate…

  1. Property.

    ERIC Educational Resources Information Center

    Piele, Philip K.

    A review of cases involving higher education property matters shows that many are concerned with building construction, equipment installation, or repair contracts. A number of other cases involve routine conflicts between colleges or universities and other governmental entities over matters such as requests for special exceptions to zoning…

  2. Property.

    ERIC Educational Resources Information Center

    Piele, Philip K.; Forsberg, James R.

    This chapter summarizes recent state supreme court and federal court decisions involving school property. The cases discussed are generally limited to those decided during 1975 and reported in the General Digest as of March 1976. In their discussion, the authors attempt to integrate related cases and to illuminate any unifying legal principles…

  3. Property.

    ERIC Educational Resources Information Center

    Piele, Philip K.

    Reflecting widespread unhappiness with the growing tax burdens in this country, the most active area of litigation reported in the property chapter this year involves various attempts by taxpayers to prevent the construction or remodeling of public school facilities. While some taxpayers fought to keep schools from being built, others in New York…

  4. Property.

    ERIC Educational Resources Information Center

    Piele, Philip K.

    The author notes that controversies over construction bids and contracts continue to represent the largest number of property cases reported in this year's chapter. Most of these cases are routine disputes between colleges or universities and contractors over such issues as the return of bid bonds, recovery of additional costs for construction…

  5. Property.

    ERIC Educational Resources Information Center

    Piele, Philip K.; Johnson, Margaret M.

    While the number of cases dealing with school property issues was significantly lower than in previous years, a significant number of cases involving the detachment and attachment of land to school districts arose. Eight of the eleven cases dealing with land detachment come from Illinois. The cases concerned requests from parents that their…

  6. Property.

    ERIC Educational Resources Information Center

    Piele, Philip K.; Forsberg, James R.

    While the types of cases reported in this year's chapter are essentially the same as those reported in last year's, the number of certain types of cases have changed--in some instances significantly. For example, the number of cases raising constitutional issues in the areas of school construction, location, and property use have declined. On the…

  7. Biogeochemical Properties of Eddies in the California Current System

    NASA Astrophysics Data System (ADS)

    Chenillat, Fanny; Franks, Peter J. S.; Combes, Vincent

    2016-04-01

    The California Current System (CCS) is a coastal upwelling system characterized by intense mesoscale activity. This mesoscale activity plays a critical role in modulating biological production and exporting coastal biogeochemical materials offshore. To characterize and quantify the ability of mesoscale eddies to affect local and regional planktonic ecosystems in the CCS, we analyzed a 10-year-long physical-biological model simulation - with 5km horizontal resolution - using eddy detection and tracking to isolate the dynamics in cyclonic and anticyclonic eddies. At any given time, ~8% of the model domain was covered by eddies, and this small area belies ~50% of the cross-shelf biological transport. As they propagate westward across the shelf, cyclonic eddies efficiently transport coastal planktonic organisms, and maintain locally elevated production, Anticyclones, on the other hand, have a limited impact on local production.

  8. Evaluation of the electromechanical properties of the cardiovascular system

    NASA Technical Reports Server (NTRS)

    Bergman, S. A., Jr.; Hoffler, G. W.; Johnson, R. L.

    1974-01-01

    Cardiovascular electromechanical measurements were collected on returning Skylab crewmembers at rest and during both lower body negative pressure and exercise stress testing. These data were compared with averaged responses from multiple preflight tests. Systolic time intervals and first heart sound amplitude changes were measured. Clinical cardiovascular examinations and clinical phonocardiograms were evaluated. All changes noted returned to normal within 30 days postflight so that the processes appear to be transient and self limited. The cardiovascular system seems to adapt quite readily to zero-g, and more importantly it is capable of readaptation to one-g after long duration space flight. Repeated exposures to zero-g also appear to have no detrimental effects on the cardiovascular system.

  9. Biogeochemical properties of eddies in the California Current System

    NASA Astrophysics Data System (ADS)

    Chenillat, Fanny; Franks, Peter J. S.; Combes, Vincent

    2016-06-01

    The California Current System (CCS) has intense mesoscale activity that modulates and exports biological production from the coastal upwelling system. To characterize and quantify the ability of mesoscale eddies to affect the local and regional planktonic ecosystem of the CCS, we analyzed a 10 year-long physical-biological model simulation, using eddy detection and tracking to isolate the dynamics of cyclonic and anticyclonic eddies. As they propagate westward across the shelf, cyclonic eddies efficiently transport coastal planktonic organisms and maintain locally elevated production for up to 1 year (800 km offshore). Anticyclonic eddies, on the other hand, have a limited impact on local production over their ~6 month lifetime as they propagate 400 km offshore. At any given time ~8% of the model domain was covered by eddy cores. Though the eddies cover a small area, they explain ~50 and 20% of the transport of nitrate and plankton, respectively.

  10. Entropic properties of D-dimensional Rydberg systems

    NASA Astrophysics Data System (ADS)

    Toranzo, I. V.; Puertas-Centeno, D.; Dehesa, J. S.

    2016-11-01

    The fundamental information-theoretic measures (the Rényi Rp [ ρ ] and Tsallis Tp [ ρ ] entropies, p > 0) of the highly-excited (Rydberg) quantum states of the D-dimensional (D > 1) hydrogenic systems, which include the Shannon entropy (p → 1) and the disequilibrium (p = 2), are analytically determined by use of the strong asymptotics of the Laguerre orthogonal polynomials which control the wavefunctions of these states. We first realize that these quantities are derived from the entropic moments of the quantum-mechanical probability ρ(r →) densities associated to the Rydberg hydrogenic wavefunctions Ψ n , l , { μ }(r →) , which are closely connected to the Lp-norms of the associated Laguerre polynomials. Then, we determine the (n → ∞)-asymptotics of these norms in terms of the basic parameters of our system (the dimensionality D, the nuclear charge and the hyperquantum numbers (n , l , { μ }) of the state) by use of recent techniques of approximation theory. Finally, these three entropic quantities are analytically and numerically discussed in terms of the basic parameters of the system for various particular states.

  11. Structural Properties and Estimation of Delay Systems. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Kwong, R. H. S.

    1975-01-01

    Two areas in the theory of delay systems were studied: structural properties and their applications to feedback control, and optimal linear and nonlinear estimation. The concepts of controllability, stabilizability, observability, and detectability were investigated. The property of pointwise degeneracy of linear time-invariant delay systems is considered. Necessary and sufficient conditions for three dimensional linear systems to be made pointwise degenerate by delay feedback were obtained, while sufficient conditions for this to be possible are given for higher dimensional linear systems. These results were applied to obtain solvability conditions for the minimum time output zeroing control problem by delay feedback. A representation theorem is given for conditional moment functionals of general nonlinear stochastic delay systems, and stochastic differential equations are derived for conditional moment functionals satisfying certain smoothness properties.

  12. Systems properties of the Haemophilus influenzae Rd metabolic genotype.

    PubMed

    Edwards, J S; Palsson, B O

    1999-06-18

    Haemophilus influenzae Rd was the first free-living organism for which the complete genomic sequence was established. The annotated sequence and known biochemical information was used to define the H. influenzae Rd metabolic genotype. This genotype contains 488 metabolic reactions operating on 343 metabolites. The stoichiometric matrix was used to determine the systems characteristics of the metabolic genotype and to assess the metabolic capabilities of H. influenzae. The need to balance cofactor and biosynthetic precursor production during growth on mixed substrates led to the definition of six different optimal metabolic phenotypes arising from the same metabolic genotype, each with different constraining features. The effects of variations in the metabolic genotype were also studied, and it was shown that the H. influenzae Rd metabolic genotype contains redundant functions under defined conditions. We thus show that the synthesis of in silico metabolic genotypes from annotated genome sequences is possible and that systems analysis methods are available that can be used to analyze and interpret phenotypic behavior of such genotypes.

  13. Site-specific analysis of dielectric properties of finite systems.

    SciTech Connect

    Jackson, K.; Yang, M.; Jellinek, J.; Chemistry; Central Michigan Univ.

    2007-12-06

    A new scheme for decomposing the total dipole moment and polarizability of a system into site-specific contributions is presented. The scheme is based on partitioning the system volume into cells associated with its atoms or groups of atoms. The site-specific dipole moments and polarizabilities are computed from the charge densities within the individual cells and the responses of these densities to an external electric field. These dipole moments and polarizabilities are further partitioned into local/dipole and charge-transfer components. The utility of the scheme is illustrated through analysis of the structure-/shape- and size-specific aspects of the dipole moments and polarizabilities of silicon clusters. It is shown that the polarizabilities associated with the individual constituent Si atoms vary considerably with the structure/shape of the cluster and the location of the atom or site within a given structure. Surface atoms, and especially those at edges, have larger polarizabilities than interior atoms. The overall contribution of the charge-transfer components to the total cluster polarizability increases with the cluster size. Finally, the anisotropy of the total polarizability correlates with the anisotropy of the cluster shape, and the charge-transfer component is the part dominantly responsible for the polarizability anisotropy.

  14. Equilibrium properties of a one-dimensional kinetic system.

    NASA Technical Reports Server (NTRS)

    Williams, J. H.; Joyce, G.

    1973-01-01

    One-dimensional systems of N = 500 and 250 particles in equilibrium are numerically simulated utilizing the method of molecular dynamics. Periodic boundary conditions are imposed. The classical two-body interaction potential is short range, repulsive and has a corresponding finite force. The equations of state are determined for densities both less and greater than one. Corresponding theoretical isochores are determined from models based on nearest-neighbor interactions and on a truncated virial expansion, and a comparison is made with the experimental isochores. Time independent radial distributions are constructed numerically and discussed. A change of state from a solidlike state to a fluid-gas state based on the penetrability of the particles is predicted. The transition temperatures are estimated from the radial distribution functions and the nearest-neighbor model. Self-diffusion is observed and the corresponding constants are determined from the velocity autocorrelation functions.

  15. Thermodynamic properties of mesoscale convective systems observed during BAMEX

    SciTech Connect

    Correia, James; Arritt, R.

    2008-11-01

    Dropsonde observations from the Bow-echo and Mesoscale convective vortex EXperiment (BAMEX) are used to document the spatio-temporal variability of temperature, moisture and wind within mesoscale convective systems (MCSs). Onion type sounding structures are found throughout the stratiform region of MCSs but the temperature and moisture variability is large. Composite soundings were constructed and statistics of thermodynamic variability were generated within each sub-region of the MCS. The calculated air vertical velocity helped identify subsaturated downdrafts. We found that lapse rates within the cold pool varied markedly throughout the MCS. Layered wet bulb potential temperature profiles seem to indicate that air within the lowest several km comes from a variety of source regions. We also found that lapse rate transitions across the 0 C level were more common than isothermal, melting layers. We discuss the implications these findings have and how they can be used to validate future high resolution numerical simulations of MCSs.

  16. System for throttling and compensation for variable feedstock properties

    DOEpatents

    Meyer, J. W.

    1981-05-05

    Apparatus is shown for adjusting the feed rate of pulverized feed material into a pressurized container. The apparatus also has utility for compensating for variations in the permeability of the feed material. A rotor that includes sprues with provision for controlling the pressure distribution along the sprues is located within the pressurized container. The rotor hub is connected to a drive means and a material supply means which extend through the wall of the container. A line for controlling pressure along the sprues by gas injection is connected to a chamber between sections of the sprue for controlling gas pressure at that point. The gas pressure control line is connected to a pressurized gas source and a control system external to the rotor. 10 figs.

  17. System for throttling and compensation for variable feedstock properties

    DOEpatents

    Meyer, John W.

    1981-01-01

    Apparatus is shown for adjusting the feed rate of pulverized feed material into a pressurized container. The apparatus also has utility for compensating for variations in the permeability of the feed material. A rotor that includes sprues with provision for controlling the pressure distribution along the sprues is located within the pressurized container. The rotor hub is connected to a drive means and a material supply means which extend through the wall of the container. A line for controlling pressure along the sprues by gas injection is connected to a chamber between sections of the sprue for controlling gas pressure at that point. The gas pressure control line is connected to a pressurized gas source and a control system external to the rotor.

  18. Soil physical properties of agricultural systems in a large-scale study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A large-scale field study was performed to determine the effects of agricultural management systems on soil physical properties, including their spatial and temporal variations. Replicates were established in 1998 at the Center for Environmental Farming Systems, Goldsboro, North Carolina; replicates...

  19. Connecting the Silicate Dust and Gas Properties of Distant Galaxies Using Quasar Absorption Systems

    NASA Astrophysics Data System (ADS)

    Aller, Monique C.; Kulkarni, Varsha P.; York, Donald G.; Welty, Daniel E.; Vladilo, Giovanni; Som, Debopam; Lackey, Kyle; Dwek, Eli; Beiranvand, Nassim; Morrison, Sean

    2016-01-01

    We present recent results from our program investigating the silicate dust properties in distant galaxies using quasar absorption systems. The dust and gas properties of distant galaxies can be characterized by studying the absorption features produced by them along the sightlines to luminous background quasars. Based on our prior finding that silicate dust absorption in z<1.5 quasar absorption systems exhibits a range of optical depths and absorption feature substructures, suggestive of silicate grain property variations, we are investigating silicate dust absorption in quasar absorption systems toward quasars with archival Spitzer Space Telescope Infrared Spectrograph (IRS) spectra. We present our measurements of the 10 and/or 18 micron silicate dust absorption feature(s) in these systems, and discuss constraints on the grain properties, such as composition and crystallinity, based on the shape and substructure present in these features. We also investigate the correlations between the silicate dust properties and the reddening. Connections between the silicate dust and gas phase metal absorption properties can also be probed for some of our targets with archival ground-based spectra. These relationships will yield valuable insights into the star formation history and evolution of metals and dust. This work is supported by NASA through ADAP grant NNX14AG74G and by an award issued by JPL/Caltech, and from US-NSF grant AST-1108830 to the University of South Carolina.

  20. Optomechanical properties of a particle-waveguide system

    NASA Astrophysics Data System (ADS)

    Maslov, A. V.

    2014-09-01

    The balances of the electromagnetic powers and momentum flows for the system of a dielectric particle and a dielectric slab waveguide are studied. The emphasis is made on the regime when whispering gallery resonances in the particle are excited. The excitation is achieved by a guided mode that has either transverse electric or magnetic polarization. The scattering problem is solved by using an analytical representation of the solution with subsequent numerical approach to find the scattered fields with high accuracy. It accounts rigorously for the interaction between the particle and the waveguide. It is found that the propelling force on the particle can be comparable to or even exceed the value of the momentum flow of the incident mode. This is related to a highly anisotropic angular distribution of the bulk radiation that can carry some noticeable momentum in the longitudinal direction. The bulk radiation carries also nonvanishing momentum in the transverse direction giving rise to a difference in the transverse forces experienced by the particle and by the waveguide. The strong coupling between the particle and the waveguide operating in the single-mode regime is shown to upshift slightly the resonant frequencies with decreasing gap between the particle and the waveguide.

  1. Conservation properties and potential systems of vorticity-type equations

    SciTech Connect

    Cheviakov, Alexei F.

    2014-03-15

    Partial differential equations of the form divN=0, N{sub t}+curl M=0 involving two vector functions in R{sup 3} depending on t, x, y, z appear in different physical contexts, including the vorticity formulation of fluid dynamics, magnetohydrodynamics (MHD) equations, and Maxwell's equations. It is shown that these equations possess an infinite family of local divergence-type conservation laws involving arbitrary functions of space and time. Moreover, it is demonstrated that the equations of interest have a rather special structure of a lower-degree (degree two) conservation law in R{sup 4}(t,x,y,z). The corresponding potential system has a clear physical meaning. For the Maxwell's equations, it gives rise to the scalar electric and the vector magnetic potentials; for the vorticity equations of fluid dynamics, the potentialization inverts the curl operator to yield the fluid dynamics equations in primitive variables; for MHD equations, the potential equations yield a generalization of the Galas-Bogoyavlenskij potential that describes magnetic surfaces of ideal MHD equilibria. The lower-degree conservation law is further shown to yield curl-type conservation laws and determined potential equations in certain lower-dimensional settings. Examples of new nonlocal conservation laws, including an infinite family of nonlocal material conservation laws of ideal time-dependent MHD equations in 2+1 dimensions, are presented.

  2. Electric properties of the Beryllium-11 system in Halo EFT

    NASA Astrophysics Data System (ADS)

    Hammer, H.-W.; Phillips, D. R.

    2011-08-01

    We compute E1 transitions and electric radii in the Beryllium-11 nucleus using an effective field theory that exploits the separation of scales in this halo system. We fix the leading-order parameters of the EFT from measured data on the 1/2 and 1/2 levels in 11Be and the B(E1) strength for the transition between them. We then obtain predictions for the B(E1) strength for Coulomb dissociation of the 11Be nucleus to the continuum. We also compute the charge radii of the 1/2 and 1/2 states. Agreement with experiment within the expected accuracy of a leading-order computation in this EFT is obtained. We also discuss how next-to-leading-order (NLO) corrections involving both s-wave and p-wave 10Be-neutron interactions affect our results, and display the NLO predictions for quantities which are free of additional short-distance operators at this order. Information on neutron- 10Be scattering in the relevant channels is inferred.

  3. The near-infrared properties of compact binary systems

    NASA Astrophysics Data System (ADS)

    Froning, Cynthia Suzanne

    I present H- and K-band light curves of the dwarf nova cataclysmic variable (CV), IP Peg, and the novalike CV, RW Tri, and an H-band light curve of the novalike CV, SW Sex. All three systems showed contributions from the late-type secondary star and the accretion disk, including a primary eclipse of the accretion disk by the secondary star and a secondary eclipse of the star by the disk. The ellipsoidal variations of the secondary star in IP Peg were modeled and subtracted from the data. The subtracted light curves show a pronounced double-hump variation, resembling those seen in the dwarf novae WZ Sge and AL Com. The primary eclipse was modeled using maximum entropy disk mapping techniques. The accretion disk has a flat intensity distribution and a low brightness temperature (Tbr ~= 3000-4000 K). Superimposed on the face of the disk is the bright spot, where the mass accretion stream impacts the disk; the position of the bright spot is different from the range of positions seen at visible wavelengths. The near-infrared accretion disk flux is dominated by optically thin emission. The eclipse depth is too shallow to be caused by a fully opaque accretion disk. The NIR light curves in RW Tri show a deep primary eclipse of the accretion disk, ellipsoidal variations from the secondary star, a secondary eclipse, and strong flickering in the disk flux. The depth of the secondary eclipse indicates that the accretion disk is opaque. The light curve also has a hump extending from φ = 0.1-0.9 which was successfully modeled as flux from the inner face of the secondary star when heated by a ~0.2 L Lsolar source. The radial brightness temperature profile of the outer disk is consistent with models of a disk in steady-state for a mass transfer rate of M~=5×10- 10 Msolaryr- 1 . At small disk radii, however, the brightness temperature profile is flatter than the steady-state model. The H-band light curve of SW Sex is dominated by emission from the accretion disk. As in RW Tri

  4. Mechanical and thermal properties of composite material system reinforced with micro glass balloons

    NASA Astrophysics Data System (ADS)

    Ozawa, Y.; Watanabe, M.; Kikuchi, T.; Ishiwatari, H.

    2010-06-01

    The mechanical and thermal properties of polymer composites reinforced with micro glass balloons are investigated in temperature conditions. The matrix resin of the composite is epoxy resin and its dispersion is micro glassy spherical shells of Sirasu Balloon. The composite system developed is a kind of micro porous materials with lightweight. From the experimental data of bending and tension tests, mechanical behaviours of the composites were clarified, and the effects of material properties and configurations on the mechanical properties of composites were discussed from the viewpoint of micromechanical study. A homogenization theory with multi-scale analytical method has been applied in order to evaluate the composite material system in temperature conditions. Numerical calculations were performed by using a model of micro porous materials and setting properties of each material at the temperature. Analytical results for the mechanical behaviour made a good agreement with experimental result of the composites in temperature conditions.

  5. Prediction of thermomagnetic and thermoelectric properties for novel materials and systems

    NASA Astrophysics Data System (ADS)

    Varlamov, A. A.; Kavokin, Alexey V.

    2013-08-01

    We express the link between conductivity and coefficients of Seebeck, Nernst-Ettingshausen, Peltier, and Thompson and Reghi-Leduc via the temperature derivative of the chemical potential of a system. These general expressions are applied to three-, two- and one-dimensional systems of charge carriers having a parabolic or Dirac spectrum. The method allows for predicting thermoelectric and thermomagnetic properties of novel materials and systems.

  6. Modelling and properties of a nonlinear autonomous switching system in fed-batch culture of glycerol

    NASA Astrophysics Data System (ADS)

    Wang, Juan; Sun, Qingying; Feng, Enmin

    2012-11-01

    A nonlinear autonomous switching system is proposed to describe the coupled fed-batch fermentation with the pH as the feedback parameter. We prove the non-Zeno behaviors of the switching system and some basic properties of its solution, including the existence, uniqueness, boundedness and regularity. Numerical simulation is also carried out, which reveals that the proposed system can describe the factual fermentation process properly.

  7. Focusing properties of a three-element quadrupole lens system and its stigmatic focusing behaviour

    NASA Astrophysics Data System (ADS)

    Zafar, Yu.

    The focusing properties of a three-element quadrupole lens system (triplet) have been studied in its general thick-lens form, and analytical expressions of corresponding matrix elements have been obtained. A graphical method has been utilized to determine the stigmatic focusing region of the triplet system generally, and in the special case of electrostatic triplet system installed in 'on-line SPIN-3 facility' in YASNAPP-2, JINR.

  8. Portable, Fiber-Based, Diffuse Reflection Spectroscopy (DRS) Systems for Estimating Tissue Optical Properties

    PubMed Central

    Vishwanath, Karthik; Chang, Kevin; Klein, Daniel; Deng, Yu Feng; Chang, Vivide; Phelps, Janelle E.; Ramanujam, Nimmi

    2010-01-01

    Steady-state diffuse reflection spectroscopy is a well-studied optical technique that can provide a noninvasive and quantitative method for characterizing the absorption and scattering properties of biological tissues. Here, we compare three fiber-based diffuse reflection spectroscopy systems that were assembled to create a light-weight, portable, and robust optical spectrometer that could be easily translated for repeated and reliable use in mobile settings. The three systems were built using a broadband light source and a compact, commercially available spectrograph. We tested two different light sources and two spectrographs (manufactured by two different vendors). The assembled systems were characterized by their signal-to-noise ratios, the source-intensity drifts, and detector linearity. We quantified the performance of these instruments in extracting optical properties from diffuse reflectance spectra in tissue-mimicking liquid phantoms with well-controlled optical absorption and scattering coefficients. We show that all assembled systems were able to extract the optical absorption and scattering properties with errors less than 10%, while providing greater than ten-fold decrease in footprint and cost (relative to a previously well-characterized and widely used commercial system). Finally, we demonstrate the use of these small systems to measure optical biomarkers in vivo in a small-animal model cancer therapy study. We show that optical measurements from the simple portable system provide estimates of tumor oxygen saturation similar to those detected using the commercial system in murine tumor models of head and neck cancer. PMID:21499501

  9. Structural and electronic properties of the graphene/Al/Ni(111) intercalation system

    NASA Astrophysics Data System (ADS)

    Voloshina, E. N.; Generalov, A.; Weser, M.; Böttcher, S.; Horn, K.; Dedkov, Yu S.

    2011-11-01

    Decoupling of the graphene layer from the ferromagnetic substrate via intercalation of sp metal has recently been proposed as an effective way to realize a single-layer graphene-based spin-filter. Here, the structural and electronic properties of the prototype system, graphene/Al/Ni(111), are investigated via a combination of electron diffraction and spectroscopic methods. These studies are accompanied by state-of-the-art electronic structure calculations. The properties of this prospective Al-intercalation-like system and its possible implementations in future graphene-based devices are discussed.

  10. An electronic system for measuring thermophysical properties of wind tunnel models

    NASA Technical Reports Server (NTRS)

    Corwin, R. R.; Kramer, J. S.

    1975-01-01

    An electronic system is described which measures the surface temperature of a small portion of the surface of the model or sample at high speeds using an infrared radiometer. This data is processed along with heating rate data from the reference heat gauge in a small computer and prints out the desired thermophysical properties, time, surface temperature, and reference heat rate. This system allows fast and accurate property measurements over thirty temperature increments. The technique, the details of the apparatus, the procedure for making these measurements, and the results of some preliminary tests are presented.

  11. Apollo Soyuz Test Project Weights and Mass Properties Operational Management System

    NASA Technical Reports Server (NTRS)

    Collins, M. A., Jr.; Hischke, E. R.

    1975-01-01

    The Apollo Soyuz Test Project (ASTP) Weights and Mass Properties Operational Management System was established to assure a timely and authoritative method of acquiring, controlling, generating, and disseminating an official set of vehicle weights and mass properties data. This paper provides an overview of the system and its interaction with the various aspects of vehicle and component design, mission planning, hardware and software simulations and verification, and real-time mission support activities. The effect of vehicle configuration, design maturity, and consumables updates is discussed in the context of weight control.

  12. Paraxial properties of three-element zoom systems for laser beam expanders.

    PubMed

    Mikš, Antonín; Novák, Pavel

    2014-09-08

    Our work is focused on the problem of theoretical analysis of paraxial properties of the three-element zoom optical system for laser beam expanders. Equations that enable to calculate mutual axial distances between individual elements of the system based on the axial position of the beam waist of the input Gaussian beam and the desired magnification of the system are derived. Finally, the derived equations are applied on an example of calculation of paraxial parameters of the three-element zoom system for the laser beam expander.

  13. Measuring the electrical properties of soil using a calibrated ground-coupled GPR system

    USGS Publications Warehouse

    Oden, C.P.; Olhoeft, G.R.; Wright, D.L.; Powers, M.H.

    2008-01-01

    Traditional methods for estimating vadose zone soil properties using ground penetrating radar (GPR) include measuring travel time, fitting diffraction hyperbolae, and other methods exploiting geometry. Additional processing techniques for estimating soil properties are possible with properly calibrated GPR systems. Such calibration using ground-coupled antennas must account for the effects of the shallow soil on the antenna's response, because changing soil properties result in a changing antenna response. A prototype GPR system using ground-coupled antennas was calibrated using laboratory measurements and numerical simulations of the GPR components. Two methods for estimating subsurface properties that utilize the calibrated response were developed. First, a new nonlinear inversion algorithm to estimate shallow soil properties under ground-coupled antennas was evaluated. Tests with synthetic data showed that the inversion algorithm is well behaved across the allowed range of soil properties. A preliminary field test gave encouraging results, with estimated soil property uncertainties (????) of ??1.9 and ??4.4 mS/m for the relative dielectric permittivity and the electrical conductivity, respectively. Next, a deconvolution method for estimating the properties of subsurface reflectors with known shapes (e.g., pipes or planar interfaces) was developed. This method uses scattering matrices to account for the response of subsurface reflectors. The deconvolution method was evaluated for use with noisy data using synthetic data. Results indicate that the deconvolution method requires reflected waves with a signal/noise ratio of about 10:1 or greater. When applied to field data with a signal/noise ratio of 2:1, the method was able to estimate the reflection coefficient and relative permittivity, but the large uncertainty in this estimate precluded inversion for conductivity. ?? Soil Science Society of America.

  14. Impact of Organic and Conventional Systems of Coffee Farming on Soil Properties and Culturable Microbial Diversity

    PubMed Central

    2016-01-01

    A study was undertaken with an objective of evaluating the long-term impacts of organic (ORG) and conventional (CON) methods of coffee farming on soil physical, chemical, biological, and microbial diversity. Electrical conductivity and bulk density were found to increase by 34% and 21%, respectively, in CON compared to ORG system, while water holding capacity was found decreased in both the systems. Significant increase in organic carbon was observed in ORG system. Major nutrients, nitrogen and potassium, levels showed inclination in both ORG and CON system, but the trend was much more pronounced in CON system. Phosphorus was found to increase in both ORG and CON system, but its availability was found to be more with CON system. In biological attributes, higher soil respiration and fluorescein diacetate activity were recorded in ORG system compared to CON system. Higher soil urease activity was observed in CON system, while dehydrogenase activity does not show significant differences between ORG and CON systems. ORG system was found to have higher macrofauna (31.4%), microbial population (34%), and microbial diversity indices compared to CON system. From the present study, it is accomplished that coffee soil under long-term ORG system has better soil properties compared to CON system. PMID:27042378

  15. Impact of Organic and Conventional Systems of Coffee Farming on Soil Properties and Culturable Microbial Diversity.

    PubMed

    Velmourougane, Kulandaivelu

    2016-01-01

    A study was undertaken with an objective of evaluating the long-term impacts of organic (ORG) and conventional (CON) methods of coffee farming on soil physical, chemical, biological, and microbial diversity. Electrical conductivity and bulk density were found to increase by 34% and 21%, respectively, in CON compared to ORG system, while water holding capacity was found decreased in both the systems. Significant increase in organic carbon was observed in ORG system. Major nutrients, nitrogen and potassium, levels showed inclination in both ORG and CON system, but the trend was much more pronounced in CON system. Phosphorus was found to increase in both ORG and CON system, but its availability was found to be more with CON system. In biological attributes, higher soil respiration and fluorescein diacetate activity were recorded in ORG system compared to CON system. Higher soil urease activity was observed in CON system, while dehydrogenase activity does not show significant differences between ORG and CON systems. ORG system was found to have higher macrofauna (31.4%), microbial population (34%), and microbial diversity indices compared to CON system. From the present study, it is accomplished that coffee soil under long-term ORG system has better soil properties compared to CON system.

  16. Barium titanate tape properties for MLCC application using different binder systems

    NASA Astrophysics Data System (ADS)

    Yoon, Dang-Hyok

    Most of multilayer ceramic capacitor (MLCC) industries are currently using solvent-based slip systems, although water-based slips have been receiving increasing attention due to reduced health and environmental hazards. The current work focuses on two main fields to meet the challenges in MLCC processing in aqueous media. One is the comparison between water- and solvent-based slip systems using design of experiments (DOE). The other is the understanding of Ba2+ ion leaching behavior in water and its effect on tape properties. For the first part, twenty four kinds of BaTiO3 slips were investigated using three different binder systems: one solvent-based, and two water-based systems. Tape casting, sintering and characterization were conducted. Slip viscosity and tape strength of the green tape depended significantly on the binder type. It was possible to achieve a higher green density for water-based system than that for a solvent-based one. Most of the green body properties from solvent-based system depended on the ceramic powder. On the other hand, the dispersant was the most significant factor for the green body properties of two water-based systems. Sintered properties such as microstructure and dielectric permittivity for three systems depended significantly on the type of ceramic powder. An optimization was performed for each system by means of a scorecard. By choosing the optimum condition, comparable results were drawn for the water-based system compared to a solvent-based one for MLCC application. For the second part, the amount of Ba2+ ion leaching from BaTiO3 in water was determined by an EDTA titration method. The greater extent and the faster rate of Ba2+ leaching were found at the lower solution pH. The excess free barium ions expressed by means of the Ba/Ti ratio adversely affected most tape properties. To passivate BaTiO 3 surface from Ba2+ ion leaching in water, passivation agent layer (PAL) was formed by drying the slurry after adding a commercial

  17. Atomistic Modeling of Surface and Bulk Properties of Cu, Pd and the Cu-Pd System

    NASA Technical Reports Server (NTRS)

    Bozzolo, Guillermo; Garces, Jorge E.; Noebe, Ronald D.; Abel, Phillip; Mosca, Hugo O.; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    The BFS (Bozzolo-Ferrante-Smith) method for alloys is applied to the study of the Cu-Pd system. A variety of issues are analyzed and discussed, including the properties of pure Cu or Pd crystals (surface energies, surface relaxations), Pd/Cu and Cu/Pd surface alloys, segregation of Pd (or Cu) in Cu (or Pd), concentration dependence of the lattice parameter of the high temperature fcc CuPd solid solution, the formation and properties of low temperature ordered phases, and order-disorder transition temperatures. Emphasis is made on the ability of the method to describe these properties on the basis of a minimum set of BFS universal parameters that uniquely characterize the Cu-Pd system.

  18. Thermal and mechanical interfacial properties of the DGEBA/PMR-15 blend system.

    PubMed

    Park, Soo-Jin; Lee, Hwa-Young; Han, Mijeong; Hong, Sung-Kwon

    2004-02-15

    In this work, the blend system of diglycidyl ether of bisphenol A and PMR-15 polyimide is investigated in terms of thermal and dynamic mechanical interfacial properties of the casting specimens. The thermal stabilities are studied by thermogravimetric and thermomechanical analyses, and the dynamic mechanical properties are carried out by dynamic mechanical analysis. The results show that the thermal stabilities based on the initial decomposition temperature, the integral procedural decomposition temperature, and the glass transition temperature are increased with increasing PMR-15 content. The crosslinking density (rho) of the blend system is increased at 10 phr of PMR-15, compared with that of neat epoxy. Mechanical interfacial properties measured in the context of critical stress intensity factor and critical strain energy release rate show similar behaviors with E(a) and rho, probably due to the increase in intermolecular interactions or hydrogen bondings in polymer chains.

  19. An electrodeless system for measurement of liquid sample dielectric properties in radio frequency band.

    PubMed

    Hartwig, V; Giovannetti, G; Vanello, N; Costantino, M; Landini, L; Benassi, A

    2006-01-01

    An electrodeless measurement system based on a resonant circuit is proposed for the measurement of dielectric properties of liquid samples at RF (radio frequency). Generally, properties as dielectric constant, loss factor and conductivity are measured by parallel plate capacitor cells: this method has several limitations in the case of particular liquid samples and in the range of radiofrequencies. Our method is based on the measurements of resonance frequency and quality factor of a LC resonant circuit in different measuring conditions, without and with the liquid sample placed inside a test tube around which the home made coil is wrapped. The measurement is performed using a network analyzer and a dual loop probe, inductively coupled with the resonant circuit. One of the advantages of this method is the contactless between the liquid sample and the measurement electrodes. In this paper the measurement system is described and test measurements of conventional liquids dielectric properties are reported.

  20. The Intrinsic Electrophysiological Properties of Mammalian Neurons: Insights into Central Nervous System Function

    NASA Astrophysics Data System (ADS)

    Llinas, Rodolfo R.

    1988-12-01

    This article reviews the electroresponsive properties of single neurons in the mammalian central nervous system (CNS). In some of these cells the ionic conductances responsible for their excitability also endow them with autorhythmic electrical oscillatory properties. Chemical or electrical synaptic contacts between these neurons often result in network oscillations. In such networks, autorhytmic neurons may act as true oscillators (as pacemakers) or as resonators (responding preferentially to certain firing frequencies). Oscillations and resonance in the CNS are proposed to have diverse functional roles, such as (i) determining global functional states (for example, sleep-wakefulness or attention), (ii) timing in motor coordination, and (iii) specifying connectivity during development. Also, oscillation, especially in the thalamo-cortical circuits, may be related to certain neurological and psychiatric disorders. This review proposes that the autorhythmic electrical properties of central neurons and their connectivity form the basis for an intrinsic functional coordinate system that provides internal context to sensory input.

  1. The intrinsic electrophysiological properties of mammalian neurons: insights into central nervous system function.

    PubMed

    Llinás, R R

    1988-12-23

    This article reviews the electroresponsive properties of single neurons in the mammalian central nervous system (CNS). In some of these cells the ionic conductances responsible for their excitability also endow them with autorhythmic electrical oscillatory properties. Chemical or electrical synaptic contacts between these neurons often result in network oscillations. In such networks, autorhythmic neurons may act as true oscillators (as pacemakers) or as resonators (responding preferentially to certain firing frequencies). Oscillations and resonance in the CNS are proposed to have diverse functional roles, such as (i) determining global functional states (for example, sleep-wakefulness or attention), (ii) timing in motor coordination, and (iii) specifying connectivity during development. Also, oscillation, especially in the thalamo-cortical circuits, may be related to certain neurological and psychiatric disorders. This review proposes that the autorhythmic electrical properties of central neurons and their connectivity form the basis for an intrinsic functional coordinate system that provides internal context to sensory input.

  2. Mechanical properties of the Shuttle Orbiter thermal protection system strain isolator pad

    NASA Technical Reports Server (NTRS)

    Sawyer, J. W.

    1982-01-01

    An experimental investigation conducted to determine the static and fatigue properties of the Strain Isolator Pad (SIP) used on the Shuttle Orbiter Thermal protection system is described. Static tension-compression and shear test results show that the SIP is highly nonlinear and that it possesses a large hysteresis, a large low modulus region for low stress levels, and stress-strain properties that are highly sensitive to strain rate and previous load history. In addition, the shear properties are also found to be sensitive to forces applied normal to the plane of the pad and to the orientation of the material. For the undensified tile/SIP system, static and fatigue failure takes place at the SIP/tile interface at low stress levels and for a small number of cycles.

  3. Navy Controls for Invoice, Receipt, Acceptance, and Property Transfer System Need Improvement

    DTIC Science & Technology

    2016-02-25

    model oversight organization in the Federal Government by leading change, speaking truth, and promoting excellence—a diverse organization, working ...Receipt, Acceptance, and Property Transfer (iR APT ) system (formerly called w ide area work f low) user organization controls administered by the...users more access than required to do their job duties because they created a work around to reject misrouted invoices. Nav y system management did not

  4. Growth of complex systems can be related to the properties of their underlying determinants

    PubMed Central

    Savageau, Michael A.

    1979-01-01

    Growth—increase in size, number, or amount—in many cases appears to follow simple empirical laws. Such laws have been noted in a wide variety of fields for many years. Until now these laws have never been related to the underlying determinants of these systems. By starting with fundamental properties of the component mechanisms in such systems, one can derive a basic growth equation for which the well-known laws of growth are special cases. PMID:16592715

  5. Synthesis of silver nanoparticles in textile finish aqueous system and their antimicrobial properties on cotton fibers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Silver nanoparticles (NPs) were synthesized by a simple and environmentally benign procedure using poly (ethylene glycol) (PEG) as reducing agent and stabilizer in the textile finish aqueous system, and their antimicrobial properties on greige (mechanically cleaned) and bleached cotton fibers were i...

  6. Sheep Grazing Effect on Dryland Soil Properties and Wheat Yield in the Wheat-Fallow System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheep (Ovis aries L.) grazing during fallow is an effective method of controlling weeds and pests in the wheat (Triticum aestivum L.)-fallow system. Little is known about the effect of sheep grazing on dryland soil properties and wheat yield. We evaluated the effects of fallow management for weed co...

  7. Sheep Grazing in the Wheat-Fallow System Affects Dryland Soil Properties and Grain Yield

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheep (Ovis aries L.) grazing during fallow is an effective method of controlling weeds and pests in the wheat (Triticum aestivum L.)-fallow system. Little is known about the effect of sheep grazing on dryland soil properties and wheat yield. We evaluated the effects of fallow management for weed co...

  8. Luminescence properties of Si-containing porous matrix–PbS nanoparticle systems

    SciTech Connect

    Tarasov, S. A. Aleksandrova, O. A.; Lamkin, I. A.; Maksimov, A. I.; Maraeva, E. V.; Mikhailov, I. I.; Moshnikov, V. A.; Musikhin, S. F.; Nalimova, S. S.; Permyakov, N. V.; Spivak, Yu. M.; Travkin, P. G.

    2015-12-15

    The luminescence properties of systems that contain lead-sulfide nanoparticles deposited onto substrates fabricated from porous silicon, oxidized porous silicon, and porous (tin-oxide)–(silicon-oxide) layers are studied. It is shown that the structure and composition of the matrix induce a strong effect on the luminescence spectra of colloidal quantum dots, defining their emission wavelength.

  9. Estimation of trunk mechanical properties using system identification: effects of experimental setup and modelling assumptions.

    PubMed

    Bazrgari, Babak; Nussbaum, Maury A; Madigan, Michael L

    2012-01-01

    The use of system identification to quantify trunk mechanical properties is growing in biomechanics research. The effects of several experimental and modelling factors involved in the system identification of trunk mechanical properties were investigated. Trunk kinematics and kinetics were measured in six individuals when exposed to sudden trunk perturbations. Effects of motion sensor positioning and properties of elements between the perturbing device and the trunk were investigated by adopting different models for system identification. Results showed that by measuring trunk kinematics at a location other than the trunk surface, the deformation of soft tissues is erroneously included into trunk kinematics and results in the trunk being predicted as a more damped structure. Results also showed that including elements between the trunk and the perturbing device in the system identification model did not substantially alter model predictions. Other important parameters that were found to substantially affect predictions were the cut-off frequency used when low-pass filtering raw data and the data window length used to estimate trunk properties.

  10. Time-averaged properties of unstable periodic orbits and chaotic orbits in ordinary differential equation systems.

    PubMed

    Saiki, Yoshitaka; Yamada, Michio

    2009-01-01

    It has recently been found in some dynamical systems in fluid dynamics that only a few unstable periodic orbits (UPOs) with low periods can give good approximations to the mean properties of turbulent (chaotic) solutions. By employing three chaotic systems described by ordinary differential equations, we compare time-averaged properties of a set of UPOs and those of a set of segments of chaotic orbits. For every chaotic system we study, the distributions of a time average of a dynamical variable along UPOs with lower and higher periods are similar to each other and the variance of the distribution is small, in contrast with that along chaotic segments. The distribution seems to converge to some limiting distribution with nonzero variance as the period of the UPO increases, although that along chaotic orbits inclines to converge to a delta -like distribution. These properties seem to lie in the background of why only a few UPOs with low periods can give good mean statistical properties in dynamical systems in fluid dynamics.

  11. Analytical model to relate DMFC material properties to optimum fuel efficiency and system size

    NASA Astrophysics Data System (ADS)

    Meyers, Jeremy P.; Bennett, Brent

    In the design of the direct methanol fuel cell and the evaluation of new materials and their appropriateness for inclusion, it is helpful to consider the impact of material properties on the performance of a complete system: to some degree, methanol crossover losses can be mitigated by proper system design. As such, an analytical model is developed to evaluate the methanol concentration profile across the anode backing layer and membrane of the direct methanol fuel cell. The model is integrated down the anode flow channel to determine fuel utilization as a function of the feed concentration, backing layer properties, and membrane properties. A minimum stoichiometric ratio is determined based on maintaining zero-order methanol kinetics, which allows the fuel efficiency to be optimized by controlling these physical properties. This analysis is then used to estimate the required flow rates and the size of system components such as the methanol storage tank, based on the minimum methanol flow rate that those components must produce to deliver a specified current; in this way, the system-level benefits of reduced membrane crossover can be evaluated.

  12. The Appearance of Equilibrium-like Properties in Driven Dissipative Systems in Complex Earth (and Other) Systems

    NASA Astrophysics Data System (ADS)

    Rundle, J. B.; Klein, W.

    2001-05-01

    Driven dissipative systems constitute some of the most important nonlinear systems in geophysics. Examples include earthquakes, mantle convection, and the geodynamo. A number of these systems also appear to show behavior that is very similar to equilibrium systems residing near a critical point, namely, the appearance of scaling laws and in some cases, nucleation. Examples of scaling laws include the Gutenberg-Richter magnitude-frequency relation, the Kolmogorov 5/3 law for turbulent fluid systems, and similar scaling laws (not named) for landslide frequency and wildfire occurrence. Examples of nucleation include earthquakes, the formation of hurricanes, and catastrophic landslides. A fundamental question is why such equilibrium-like scaling laws should be demonstrated in manifestly non-equilibrium systems, and why in many cases such systems seem to have ergodic properties. The answer to this question, at least in some cases, is evidently connected to the long-range nature of the interactions with which various parts of the system communicate. In recent years, a number of studies (JBR et al., Phys. Rev. Lett., 75, 1658, 1995; WK et al., Phys. Rev. Lett., 78, 3793, 1997; G. Morein et al., Geophys. J. Int., 131, 552, 1997; D. Fisher et al., Phys. Rev. Lett., 78, 4885, 1997; CD Ferguson et al., Phys. Rev. E., 60, 1359, 1999; DA Egolf, Science, 287, 101, 2000; IG Main et al., J. Geophys. Res., 105, 6105, 2000; A. Hunt, Geophys. Res. Lett., in press, 2001) have shown that when a system has mean field properties arising from long range interactions, together with a dynamical randomizing ("thermalizing") mechanisim, the system demonstrates ergodic behavior. In this lecture, I discuss these issues, along with recent examples that demonstrate how nucleation and critical phenomena arise, and how these processes can be physically understood. I also discuss how these results apply to other systems.

  13. 32 CFR 37.605 - What is the general policy on participants' financial, property, and purchasing systems?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT REGULATIONS TECHNOLOGY INVESTMENT AGREEMENTS... management, property management, and purchasing systems than they currently use for: (a)...

  14. Computational Tools for Predictive Modeling of Properties in Complex Actinide Systems

    SciTech Connect

    Autschbach, Jochen; Govind, Niranjan; Atta Fynn, Raymond; Bylaska, Eric J.; Weare, John H.; de Jong, Wibe A.

    2015-03-30

    In this chapter we focus on methodological and computational aspects that are key to accurately modeling the spectroscopic and thermodynamic properties of molecular systems containing actinides within the density functional theory (DFT) framework. Our focus is on properties that require either an accurate relativistic all-electron description or an accurate description of the dynamical behavior of actinide species in an environment at finite temperature, or both. The implementation of the methods and the calculations discussed in this chapter were done with the NWChem software suite (Valiev et al. 2010). In the first two sections we discuss two methods that account for relativistic effects, the ZORA and the X2C Hamiltonian. Section 1.2.1 discusses the implementation of the approximate relativistic ZORA Hamiltonian and its extension to magnetic properties. Section 1.3 focuses on the exact X2C Hamiltonian and the application of this methodology to obtain accurate molecular properties. In Section 1.4 we examine the role of a dynamical environment at finite temperature as well as the presence of other ions on the thermodynamics of hydrolysis and exchange reaction mechanisms. Finally, Section 1.5 discusses the modeling of XAS (EXAFS, XANES) properties in realistic environments accounting for both the dynamics of the system and (for XANES) the relativistic effects.

  15. [Physical imaging properties of a flat panel X-ray detector system].

    PubMed

    Yoshida, Akira; Nakamura, Satoru; Nishihara, Sadamitsu; Kohama, Chiyuki; Takahata, Akira; Fujikawa, Kouichi

    2002-01-01

    We report the physical imaging properties of a flat panel detector (FPD) designed for radiographic imaging applications (Revolution XQ/i digital chest imaging system, G.E. Medical Systems). The imaging properties of the detector were evaluated through measurements of the characteristic curve, modulation transfer function (MTF), and Wiener spectrum. The digital characteristic curves of the FPD system were measured for the two tube voltages (80 kV and 120 kV). They showed that the correlation between the pixel values of FPD and the incident exposure to the FPD was a linear correlation. The dynamic range of characteristic curves had a range from about 0.003 to 2 microC/kg at the exposure. The presampling MTFs for different tube voltage were almost the same, when we measured the MTFs at 80 kV and 120 kV. And also, there was no significant difference between the MTFs measured with the slit in the direction parallel to the horizontal direction and with the slit in the perpendicular direction. The relative resolution of the FPD system was a 46% higher than that of ST-V imaging plate of FCR (Fuji Computed Radiography) system at 2 cycles/mm. The digital Wiener spectrum of the FPD system was about 1/10 lower than that of the CR system. Thus the FPD system can provide superior imaging performance due to both high resolution and low noise.

  16. Lotka-Volterra systems satisfying a strong Painlevé property

    NASA Astrophysics Data System (ADS)

    Bountis, Tassos; Vanhaecke, Pol

    2016-12-01

    We use a strong version of the Painlevé property to discover and characterize a new class of n-dimensional Hamiltonian Lotka-Volterra systems, which turn out to be Liouville integrable as well as superintegrable. These systems are in fact Nambu systems, they posses Lax equations and they can be explicitly integrated in terms of elementary functions. We apply our analysis to systems containing only quadratic nonlinearities of the form aijxixj , i ≠ j, and require that all variables diverge as t-1. We also require that the leading terms depend on n - 2 free parameters. We thus discover a cocycle relation among the coefficients aij of the equations of motion and by integrating the cocycle equations we show that they are equivalent to the above strong version of the Painlevé property. We also show that these systems remain explicitly solvable even if a linear term bixi is added to the i-th equation, even though this violates the Painlevé property, as logarithmic singularities are introduced in the Laurent solutions, at the first terms following the leading order pole.

  17. Wave function properties of a single and a system of magnetic flux tube(s) oscillations

    NASA Astrophysics Data System (ADS)

    Esmaeili, Shahriar; Nasiri, Mojtaba; Dadashi, Neda; Safari, Hossein

    2016-10-01

    In this study, the properties of wave functions of the MHD oscillations for a single and a system of straight flux tubes are investigated. Magnetic flux tubes with a straight magnetic field and longitudinal density stratification were considered in zero-β approximation. A single three-dimensional wave equation (eigenvalue problem) is solved for longitudinal component of the perturbed magnetic field using the finite element method. Wave functions (eigenfunction of wave equation) of the MHD oscillations are categorized into sausage, kink, helical kink, and fluting modes. Exact recognition of the wave functions and the frequencies of oscillations can be used in coronal seismology and also helps to the future high-resolution instruments that would be designed for studying the properties of the solar loop oscillations in details. The properties of collective oscillations of nonidentical and identical system of flux tubes and their interactions are studied. The ratios of frequencies, the oscillation frequencies of a system of flux tubes to their equivalent monolithic tube (ω sys/ω mono), are obtained between 0.748 and 0.841 for a system of nonidentical tubes, whereas the related ratios of frequencies for a system of identical flux tubes are fluctuated around 0.761.

  18. Impact of future fuel properties on aircraft engines and fuel systems

    NASA Technical Reports Server (NTRS)

    Rudey, R. A.; Grobman, J. S.

    1978-01-01

    This paper describes and discusses the propulsion-system problems that will most likely be encountered if the specifications of hydrocarbon-based jet fuels must undergo significant changes in the future and, correspondingly, the advances in technology that will be required to minimize the adverse impact of these problems. Several investigations conducted are summarized. Illustrations are used to describe the relative effects of selected fuel properties on the behavior of propulsion-system components and fuel systems. The selected fuel properties are those that are most likely to be relaxed in future fuel specifications. Illustrations are also used to describe technological advances that may be needed in the future. Finally, the technological areas needing the most attention are described, and programs that are under way to address these needs are briefly discussed.

  19. Experimental Design for Determination of Effects of Superdisintegrant Combinations on Liquisolid System Properties.

    PubMed

    Vraníková, Barbora; Pavloková, Sylvie; Gajdziok, Jan

    2017-03-01

    The preparation of liquisolid systems presents a promising and innovative possibility for enhancing dissolution profiles and improving the bioavailability of poorly soluble drugs. This study aims to evaluate the differences in the properties of liquisolid systems containing combinations of 3 commercially used superdisintegrants (sodium starch glycolate, crospovidone, and croscarmellose sodium). Multiple regression models and contour plots were used to study how the amount and the type of superdisintegrant used affected the quality parameters of liquisolid tablets. The results revealed that an increased amount of crospovidone in the mixture improves disintegration and wetting time and enhances drug release from the prepared liquisolid tablets. Moreover, it was observed that a binary blend of crospovidone and sodium starch glycolate improved tablet disintegration. Considering the obtained results, it could be stated that crospovidone showed the best properties to be used as superdisintegrant for the preparation of liquisolid systems containing rosuvastatin.

  20. Sorbent Material Property Requirements for On-Board Hydrogen Storage for Automotive Fuel Cell Systems.

    SciTech Connect

    Ahluwalia, R. K.; Peng, J-K; Hua, T. Q.

    2015-05-25

    Material properties required for on-board hydrogen storage in cryogenic sorbents for use with automotive polymer electrolyte membrane (PEM) fuel cell systems are discussed. Models are formulated for physical, thermodynamic and transport properties, and for the dynamics of H-2 refueling and discharge from a sorbent bed. A conceptual storage configuration with in-bed heat exchanger tubes, a Type-3 containment vessel, vacuum insulation and requisite balance-of-plant components is developed to determine the peak excess sorption capacity and differential enthalpy of adsorption for 5.5 wt% system gravimetric capacity and 55% well-to-tank (WTT) efficiency. The analysis also determines the bulk density to which the material must be compacted for the storage system to reach 40 g.L-1 volumetric capacity. Thermal transport properties and heat transfer enhancement methods are analyzed to estimate the material thermal conductivity needed to achieve 1.5 kg.min(-1) H-2 refueling rate. Operating temperatures and pressures are determined for 55% WTT efficiency and 95% usable H-2. Needs for further improvements in material properties are analyzed that would allow reduction of storage pressure to 50 bar from 100 bar, elevation of storage temperature to 175-200 K from 150 K, and increase of WTT efficiency to 57.5% or higher.

  1. The geometry, controllability, and flatness property of the n-bar system

    NASA Astrophysics Data System (ADS)

    Li, Shun-Jie; Respondek, Witold

    2011-05-01

    We propose a kinematic model of a system moving in an (m + 1)-dimensional euclidean space and consisting of n rigid bars attached successively to each other and subject to the nonholonomic constraints that the instantaneous velocity of the source point of each bar is parallel to that bar. We prove that the associated control system is controllable and feedback equivalent to the m-chained form around any regular configuration. As a consequence, we deduce that the n-bar system is flat and show that the Cartesian position of the source point of the last (from the top) bar is a flat output. The n-bar system is a natural generalisation of the n-trailer system and we provide a comparison of flatness properties of both systems.

  2. A COAXIAL TE011 CAVITY AND A SYSTEM TO MEASURE DC AND RF PROPERTIES OF SUPERCONDUCTORS

    SciTech Connect

    Gianluigi Ciovati; Peter Kneisel; Ganapati Rao Myneni; Larry Turlington; Gary Slack; Michael Morrone; William Clemens; Richard Bundy; Thomas Elliott; Jayanta Mondal

    2008-01-23

    A coaxial niobium cavity has been designed and built where the center conductor consists of a removable sample. In addition, a system to measure properties such as magnetization, penetration depth, critical temperature and thermal conductivity on the same cylindrical sample has been designed and built. The purpose of this effort is to investigate possible correlations between DC and RF properties of superconductors. In this contribution, the design of the various components is discussed and the test results on a niobium sample obtained so far are presented.

  3. Porosity Dependence of Piezoelectric Properties for Porous Potassium Niobate System Ceramics

    NASA Astrophysics Data System (ADS)

    Wada, S.; Mase, Y.; Shimizu, S.; Maeda, K.; Fujii, I.; Nakashima, K.; Pulpan, P.; Miyajima, N.

    2011-10-01

    Porous potassium niobate (KNbO3, KN) system ceramics were prepared by a conventional sintering method using carbon black (CB) nanoparticles. First, KN nanoparticles with a size of 100 nm was mixed with CB nanoparticles and binder using ball milling with ethanol. The mixture was dried, and pressed into pellets using uniaxial pressing. After binder burnout, these ceramics was sintered in air. Their piezoelectric properties were measured and discussed a relationship between porosity and piezoelectric properties. As the results, with increasing porosity, piezoelectric g33 constant increased significantly, which suggested that porous ceramics were effective for stress sensor application.

  4. The influence of the semiconductor and dielectric properties on surface flashover in silicon-dielectric systems

    SciTech Connect

    Gradinaru, G.; Madangarli, V.P.; Sudarshan, T.S. . Dept. of Electrical and Computer Engineering)

    1994-07-01

    New experimental results on surface flashover are reported for high field silicon-dielectric systems. Different conditions of the lateral surface, contacts and ambient dielectrics have been studied. The strong influence of the semiconductor quality, and that of the dielectric properties, on the prebreakdown and breakdown response of the system, is demonstrated. All experimental results strongly support the conclusion that surface flashover in silicon systems is a physical process totally different from semiconductor surface breakdown. This conclusion has important practical application in the improvement of the performance of photoconductive power switches, severely limited by premature breakdown effects.

  5. Healing efficiency and dynamic mechanical properties of self-healing epoxy systems

    NASA Astrophysics Data System (ADS)

    Guadagno, Liberata; Raimondo, Marialuigia; Naddeo, Carlo; Longo, Pasquale; Mariconda, Annaluisa; Binder, Wolfgang H.

    2014-03-01

    Several systems to develop self-repairing epoxy resins have recently been formulated. In this paper the effect of matrix nature and curing cycle on the healing efficiency and dynamic mechanical properties of self-healing epoxy resins were investigated. We discuss several aspects by transferring self-healing systems from the laboratory scale to real applications in the aeronautic field, such as the possibility to choose systems with increased glass transition temperature, high storage modulus and high values in the healing functionality under real working conditions.

  6. Anisotropic dielectric properties of two-dimensional matrix in pseudo-spin ferroelectric system

    NASA Astrophysics Data System (ADS)

    Kim, Se-Hun

    2016-10-01

    The anisotropic dielectric properties of a two-dimensional (2D) ferroelectric system were studied using the statistical calculation of the pseudo-spin Ising Hamiltonian model. It is necessary to delay the time for measurements of the observable and the independence of the new spin configuration under Monte Carlo sampling, in which the thermal equilibrium state depends on the temperature and size of the system. The autocorrelation time constants of the normalized relaxation function were determined by taking temperature and 2D lattice size into account. We discuss the dielectric constants of a two-dimensional ferroelectric system by using the Metropolis method in view of the Slater-Takagi defect energies.

  7. Abasy Atlas: a comprehensive inventory of systems, global network properties and systems-level elements across bacteria

    PubMed Central

    Ibarra-Arellano, Miguel A.; Campos-González, Adrián I.; Treviño-Quintanilla, Luis G.; Tauch, Andreas; Freyre-González, Julio A.

    2016-01-01

    The availability of databases electronically encoding curated regulatory networks and of high-throughput technologies and methods to discover regulatory interactions provides an invaluable source of data to understand the principles underpinning the organization and evolution of these networks responsible for cellular regulation. Nevertheless, data on these sources never goes beyond the regulon level despite the fact that regulatory networks are complex hierarchical-modular structures still challenging our understanding. This brings the necessity for an inventory of systems across a large range of organisms, a key step to rendering feasible comparative systems biology approaches. In this work, we take the first step towards a global understanding of the regulatory networks organization by making a cartography of the functional architectures of diverse bacteria. Abasy (Across-bacteria systems) Atlas provides a comprehensive inventory of annotated functional systems, global network properties and systems-level elements (global regulators, modular genes shaping functional systems, basal machinery genes and intermodular genes) predicted by the natural decomposition approach for reconstructed and meta-curated regulatory networks across a large range of bacteria, including pathogenically and biotechnologically relevant organisms. The meta-curation of regulatory datasets provides the most complete and reliable set of regulatory interactions currently available, which can even be projected into subsets by considering the force or weight of evidence supporting them or the systems that they belong to. Besides, Abasy Atlas provides data enabling large-scale comparative systems biology studies aimed at understanding the common principles and particular lifestyle adaptions of systems across bacteria. Abasy Atlas contains systems and system-level elements for 50 regulatory networks comprising 78 649 regulatory interactions covering 42 bacteria in nine taxa, containing 3708

  8. Study of the optical properties of solid tissue phantoms using single and double integrating sphere systems

    NASA Astrophysics Data System (ADS)

    Monem, S.; Singh, A.; Karsten, A. E.; Amin, R.; Harith, M. A.

    2015-12-01

    Tissue simulators, the so-called tissue phantoms, have been used to mimic human tissue for spectroscopic applications. Phantoms' design depends on patterning the optical properties, namely absorption and scattering coefficients which characterize light propagation mechanisms inside the tissues. In this work, two calibration models based on measurements adopting integrating sphere systems have been used to determine the optical properties of the studied solid phantoms. Integrating sphere measurement results were fed into the calibration models using the multiple polynomial regression method and Newton-Raphson algorithm. The third-order polynomials have been used for optical properties predictions. Good agreement between the two models has been obtained. Role of solid phantoms' components, namely titanium dioxide as a scatterer and black carbon as an absorber, has been discussed. Both of the two components showed observable effects on the absorption and scattering of light inside the solid tissue phantoms.

  9. Pharmaceutical cocrystals, salts and multicomponent systems; intermolecular interactions and property based design.

    PubMed

    Berry, David J; Steed, Jonathan W

    2017-03-23

    As small molecule drugs become harder to develop and less cost effective for patient use, efficient strategies for their property improvement become increasingly important to global health initiatives. Improvements in the physical properties of Active Pharmaceutical Ingredients (APIs), without changes in the covalent chemistry, have long been possible through the application of binary component solids. This was first achieved through the use of pharmaceutical salts, within the last 10-15years with cocrystals and more recently coamorphous systems have also been consciously applied to this problem. In order to rationally discover the best multicomponent phase for drug development, intermolecular interactions need to be considered at all stages of the process. This review highlights the current thinking in this area and the state of the art in: pharmaceutical multicomponent phase design, the intermolecular interactions in these phases, the implications of these interactions on the material properties and the pharmacokinetics in a patient.

  10. REVIEWS OF TOPICAL PROBLEMS: Properties of high pressure phases in metal-hydrogen systems

    NASA Astrophysics Data System (ADS)

    Ponyatovskiĭ, E. G.; Antonov, Vladimir E.; Belash, I. T.

    1982-08-01

    The development of high-pressure technology has in recent years permitted obtaining extensive new information on the properties of hydrides of group VI-VIII transition metals. In this review, the experimental procedures for compressing macroscopic quantities of hydrogen to record high pressures, phase transitions, and structures of new high-pressure phases in Me-H systems are briefly described. Special attention is devoted to the magnetic properties of solid solutions of hydrogen in 3d metals and their alloys, whose study has yielded definite conclusions concerning the effect of hydrogen on the band structure and exchange interaction in these materials. The role of structural instabilities in the formation of superconducting properties of hydrogen solutions in 4d metal alloys based on palladium is examined.

  11. Materials properties numerical database system established and operational at CINDAS/Purdue University

    NASA Technical Reports Server (NTRS)

    Ho, C. Y.; Li, H. H.

    1989-01-01

    A computerized comprehensive numerical database system on the mechanical, thermophysical, electronic, electrical, magnetic, optical, and other properties of various types of technologically important materials such as metals, alloys, composites, dielectrics, polymers, and ceramics has been established and operational at the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) of Purdue University. This is an on-line, interactive, menu-driven, user-friendly database system. Users can easily search, retrieve, and manipulate the data from the database system without learning special query language, special commands, standardized names of materials, properties, variables, etc. It enables both the direct mode of search/retrieval of data for specified materials, properties, independent variables, etc., and the inverted mode of search/retrieval of candidate materials that meet a set of specified requirements (which is the computer-aided materials selection). It enables also tabular and graphical displays and on-line data manipulations such as units conversion, variables transformation, statistical analysis, etc., of the retrieved data. The development, content, accessibility, etc., of the database system are presented and discussed.

  12. Mechanical properties of particle systems using a molecular dynamics approach inspired by continuum homogenization

    NASA Astrophysics Data System (ADS)

    Andia, Pedro C.

    The topic of this dissertation is the study of the mechanical properties of solid material systems at the nanoscale. At such length scales, materials can be viewed as particle systems, and molecular dynamics (MD) simulations help one understand their behavior as well as quantify their properties. However, mechanical concepts such as strain, stress and moduli were originally developed in continuum models, which are typically applied in space scales that range from the microscopic to the macroscopic. For this reason, a careful translation of ideas from continuum scales to the nanoscale is necessary. In essence, this thesis reviews and refines the continuum notions of average mechanical properties, such as stress and strain, and the meaning of such notions when MD is used to compute them. A Lagrangian-based approach is utilized for the purpose of determining the stress-deformation behavior of continua as well as of particle systems. At the continuum level, the mentioned Lagrangian-based approach is applied within homogenization theory for developing a nonlinear continuum homogenization model, which includes a novel constitutive relation for the stress. At the nanoscale, an MD method is presented as the extension of the continuum homogenization model. This MD method is able to simulate the behavior of particle systems under a given type of deformation as well as to generate stress-strain curves. In the process of developing the MD method, some concepts and techniques commonly used in MD, such as the virial stress and the Parrinello-Rahman method, are clarified.

  13. Influence of the viscoelastic properties of the respiratory system on the energetically optimum breathing frequency.

    PubMed

    Bates, J H; Milic-Emili, J

    1993-01-01

    We hypothesized that the viscoelastic properties of the respiratory system should have significant implications for the energetically optimal frequency of breathing, in view of the fact that these properties cause marked dependencies of overall system resistance and elastance on frequency. To test our hypothesis we simulated two models of canine and human respiratory system mechanics during sinusoidal breathing and calculated the inspiratory work (WI) and pressure-time integral (PTI) per minute under both resting and exercise conditions. The two models were a two-compartment viscoelastic model and a single-compartment model. Requiring minute alveolar ventilation to be fixed, we found that both models predicted almost identical optimum breathing frequencies. The calculated PTI was very insensitive to increases in breathing frequency above the optimal frequencies, while WI was found to increase slowly with frequency above its optimum. In contrast, both WI and PTI increased sharply as frequency decreased below their respective optima. A sensitivity analysis showed that the model predictions were very insensitive to the elastance and resistance values chosen to characterize tissue viscoelasticity. We conclude that the WI criterion for choosing the frequency of breathing is compatible with observations in nature, whereas the optimal frequency predictions of the PTI are rather too high. Both criteria allow for a fairly wide margin of choice in frequency above the optimum values without incurring excessive additional energy expenditure. Furthermore, contrary to our expectations, the viscoelastic properties of the respiratory system tissues do not pose a noticeable problem to the respiratory controller in terms of energy expenditure.

  14. Study of Microfluidic System for Mechanical Property Measurement of Fluid-cell Interface

    NASA Astrophysics Data System (ADS)

    Moon, Ji Young; Lee, Jung Shin; Choi, Se Bin; Yoon, Hong Min; Tanner, Roger I.; Lee, Joon Sang

    2016-11-01

    The system for measuring the mechanical properties of active cell is studied through an integrated microfluidic system for cell separation, alignment and measurement of mechanical properties. A highly efficient lattice Boltzmann method (LBM) was employed to optimize the micro-fluidic system to investigate the interrelations between mechanical properties and various surrounding fluid ingredients which are difficult to observe using current experimental techniques. A combination model of the three dimensional LBM and the immersed boundary method (IBM) were used to simulate these systems. The LBM was used to determine incompressible fluid flow with a regular Eulerian grid. The IBM was used to solve the deformation of cells and matrix fluid interaction with a Lagrangian grid. Highly non-linear results such as cell-cell interactions, fluid-cell interactions, and optical force-cell interactions is studied. National Research Foundation of Korea (NRF) (Grant Number: NRF-2015R1A2A1A15056182, NRF-2015R1A5A1037668).

  15. The effect of the liquid-solid system properties on the interline heat transfer coefficient

    NASA Technical Reports Server (NTRS)

    Wayner, P. C., Jr.

    1977-01-01

    A theoretical procedure to determine the heat transfer characteristics of the interline region of an evaporating meniscus using the macroscopic optical and thermophysical properties of the system is outlined. The analysis is based on the premise that the interline transport processes are controlled by the London-van der Waals forces between condensed phases (solid and liquid). The procedure is used to compare the relative size of the interline heat sink of various systems using a constant heat flux model. This solution demonstrates the importance of the interline heat flow number which is evaluated for various systems. The heat transfer characteristics of the decane-steel system are numerically compared with those of the carbon tetrachloride-quartz system.

  16. Dynamical properties and complexity in fractional-order diffusionless Lorenz system

    NASA Astrophysics Data System (ADS)

    He, Shaobo; Sun, Kehui; Banerjee, Santo

    2016-08-01

    In this paper, dynamics and complexity of the fractional-order diffusionless Lorenz system which is solved by the developed discrete Adomian decomposition method are investigated numerically. Dynamical properties of the fractional-order diffusionless Lorenz system with the control parameter and derivative order varying is analyzed by using bifurcation diagrams, and period-doubling route to chaos in different cases is observed. The complexity of the system is investigated by means of Lyapunov characteristic exponents, multi-scale spectral entropy algorithm and multiscale Renyi permutation entropy algorithm. It can be observed that the three methods illustrate consistent results and the system has rich complex dynamics. Interestingly, complexity decreases with the increase of derivative order. It shows that the fractional-order diffusionless Lorenz system is a good model for real applications such as information encryption and secure communication.

  17. The psychology of potential threat: properties of the security motivation system.

    PubMed

    Hinds, Andrea L; Woody, Erik Z; Drandic, Ana; Schmidt, Louis A; Van Ameringen, Michael; Coroneos, Marie; Szechtman, Henry

    2010-10-01

    Results of three experiments support hypothesized properties of the security motivation system, a special motivational system for handling potential threats, as proposed by Szechtman and Woody (2004). First, mild stimuli suggesting potential harm produced a marked state of activation (evident in both objective and subjective measures), consistent with the hypothesis that the security motivation system is finely tuned for the detection of potential threat. Second, in the absence of corrective behavior, this evoked activation is persistent, supporting the hypothesis that once stimulated, the security motivation system produces an enduring motivational state involving the urge to engage in threat-reducing behavior. Third, engagement in corrective behavior was effective in returning activation levels to baseline, whereas cognitive reappraisal was not. These findings are consistent with the hypothesis that deactivation of the security motivation system depends on performance of security-related behaviors, rather than non-behavioral events such as cognitive re-evaluation of threat.

  18. Efficient implementation of a real-time estimation system for thalamocortical hidden Parkinsonian properties

    PubMed Central

    Yang, Shuangming; Deng, Bin; Wang, Jiang; Li, Huiyan; Liu, Chen; Fietkiewicz, Chris; Loparo, Kenneth A.

    2017-01-01

    Real-time estimation of dynamical characteristics of thalamocortical cells, such as dynamics of ion channels and membrane potentials, is useful and essential in the study of the thalamus in Parkinsonian state. However, measuring the dynamical properties of ion channels is extremely challenging experimentally and even impossible in clinical applications. This paper presents and evaluates a real-time estimation system for thalamocortical hidden properties. For the sake of efficiency, we use a field programmable gate array for strictly hardware-based computation and algorithm optimization. In the proposed system, the FPGA-based unscented Kalman filter is implemented into a conductance-based TC neuron model. Since the complexity of TC neuron model restrains its hardware implementation in parallel structure, a cost efficient model is proposed to reduce the resource cost while retaining the relevant ionic dynamics. Experimental results demonstrate the real-time capability to estimate thalamocortical hidden properties with high precision under both normal and Parkinsonian states. While it is applied to estimate the hidden properties of the thalamus and explore the mechanism of the Parkinsonian state, the proposed method can be useful in the dynamic clamp technique of the electrophysiological experiments, the neural control engineering and brain-machine interface studies. PMID:28065938

  19. Efficient implementation of a real-time estimation system for thalamocortical hidden Parkinsonian properties

    NASA Astrophysics Data System (ADS)

    Yang, Shuangming; Deng, Bin; Wang, Jiang; Li, Huiyan; Liu, Chen; Fietkiewicz, Chris; Loparo, Kenneth A.

    2017-01-01

    Real-time estimation of dynamical characteristics of thalamocortical cells, such as dynamics of ion channels and membrane potentials, is useful and essential in the study of the thalamus in Parkinsonian state. However, measuring the dynamical properties of ion channels is extremely challenging experimentally and even impossible in clinical applications. This paper presents and evaluates a real-time estimation system for thalamocortical hidden properties. For the sake of efficiency, we use a field programmable gate array for strictly hardware-based computation and algorithm optimization. In the proposed system, the FPGA-based unscented Kalman filter is implemented into a conductance-based TC neuron model. Since the complexity of TC neuron model restrains its hardware implementation in parallel structure, a cost efficient model is proposed to reduce the resource cost while retaining the relevant ionic dynamics. Experimental results demonstrate the real-time capability to estimate thalamocortical hidden properties with high precision under both normal and Parkinsonian states. While it is applied to estimate the hidden properties of the thalamus and explore the mechanism of the Parkinsonian state, the proposed method can be useful in the dynamic clamp technique of the electrophysiological experiments, the neural control engineering and brain-machine interface studies.

  20. Upper tropospheric cloud systems derived from IR sounders: properties of cirrus anvils in the tropics

    NASA Astrophysics Data System (ADS)

    Protopapadaki, Sofia E.; Stubenrauch, Claudia J.; Feofilov, Artem G.

    2017-03-01

    Representing about 30 % of the Earth's total cloud cover, upper tropospheric clouds play a crucial role in the climate system by modulating the Earth's energy budget and heat transport. When originating from convection, they often form organized systems. The high spectral resolution of the Atmospheric Infrared Sounder (AIRS) allows reliable cirrus identification, both from day and nighttime observations. Tropical upper tropospheric cloud systems have been analyzed by using a spatial composite technique on the retrieved cloud pressure of AIRS data. Cloud emissivity is used to distinguish convective core, cirrus and thin cirrus anvil within these systems. A comparison with simultaneous precipitation data from the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) shows that, for tropical upper tropospheric clouds, a cloud emissivity close to 1 is strongly linked to a high rain rate, leading to a proxy to identify convective cores. Combining AIRS cloud data with this cloud system approach, using physical variables, provides a new opportunity to relate the properties of the anvils, including also the thinner cirrus, to the convective cores. It also distinguishes convective cloud systems from isolated cirrus systems. Deep convective cloud systems, covering 15 % of the tropics, are further distinguished into single-core and multi-core systems. Though AIRS samples the tropics only twice per day, the evolution of longer-living convective systems can be still statistically captured, and we were able to select relatively mature single-core convective systems by using the fraction of convective core area within the cloud systems as a proxy for maturity. For these systems, we have demonstrated that the physical properties of the anvils are related to convective depth, indicated by the minimum retrieved cloud temperature within the convective core. Our analyses show that the size of the systems does in general increase with convective depth, though for

  1. Energy landscape analysis of the subcortical brain network unravels system properties beneath resting state dynamics.

    PubMed

    Kang, Jiyoung; Pae, Chongwon; Park, Hae-Jeong

    2017-04-01

    The configuration of the human brain system at rest, which is in a transitory phase among multistable states, remains unknown. To investigate the dynamic systems properties of the human brain at rest, we constructed an energy landscape for the state dynamics of the subcortical brain network, a critical center that modulates whole brain states, using resting state fMRI. We evaluated alterations in energy landscapes following perturbation in network parameters, which revealed characteristics of the state dynamics in the subcortical brain system, such as maximal number of attractors, unequal temporal occupations, and readiness for reconfiguration of the system. Perturbation in the network parameters, even those as small as the ones in individual nodes or edges, caused a significant shift in the energy landscape of brain systems. The effect of the perturbation on the energy landscape depended on the network properties of the perturbed nodes and edges, with greater effects on hub nodes and hubs-connecting edges in the subcortical brain system. Two simultaneously perturbed nodes produced perturbation effects showing low sensitivity in the interhemispheric homologous nodes and strong dependency on the more primary node among the two. This study demonstrated that energy landscape analysis could be an important tool to investigate alterations in brain networks that may underlie certain brain diseases, or diverse brain functions that may emerge due to the reconfiguration of the default brain network at rest.

  2. Computer-assisted analyses of the thermodynamic properties of slags in coal-combustion systems

    SciTech Connect

    Blander, M.; Pelton, A.D.

    1983-09-01

    Equations were developed for the analysis of the thermodynamic properties of molten silicate solutions; the equations take into account the unusual concentration and temperature dependence of the solution properties of ordered systems. For binary systems, these equations were coupled with an optimization computer program to analyze all reliable thermodynamic data, including phase diagrams, free energies and enthalpies of formation of compounds, activities of components, enthalpies of mixing, entropies of fusion, miscibility gaps, etc. In this manner, we analyzed data for five binary systems: CaO-SiO/sub 2/, Na/sub 2/O-SiO/sub 2/, CaO-Al/sub 2/O/sub 3/, Na/sub 2/O-Al/sub 2/O/sub 3/, and Al/sub 2/O/sub 3/-SiO/sub 2/. The results of the binary systems were combined, and an analysis done of three ternary systems: CaO-Al/sub 2/O/sub 3/-SiO/sub 2/, Na/sub 2/O-CaO-SiO/sub 2/, and Na/sub 2/O-Al/sub 2/O/sup 3/-SiO/sub 2/. A tentative analysis of the quaternary system, Na/sub 2/O-CaO-Al/sub 2/O/sub 3/-SiO/sub 2/, was also undertaken. 53 references, 51 figures, 3 tables.

  3. 26 CFR 1.167(l)-4 - Public utility property; election to use asset depreciation range system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... depreciation range system. 1.167(l)-4 Section 1.167(l)-4 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT... Individuals and Corporations § 1.167(l)-4 Public utility property; election to use asset depreciation range system. (a) Application of section 167(l) to certain property subject to asset depreciation range...

  4. 26 CFR 1.167(l)-4 - Public utility property; election to use asset depreciation range system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... depreciation range system. 1.167(l)-4 Section 1.167(l)-4 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT... Individuals and Corporations § 1.167(l)-4 Public utility property; election to use asset depreciation range system. (a) Application of section 167(l) to certain property subject to asset depreciation range...

  5. 26 CFR 1.167(l)-4 - Public utility property; election to use asset depreciation range system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... depreciation range system. 1.167(l)-4 Section 1.167(l)-4 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT... Individuals and Corporations § 1.167(l)-4 Public utility property; election to use asset depreciation range system. (a) Application of section 167(l) to certain property subject to asset depreciation range...

  6. 26 CFR 1.167(l)-4 - Public utility property; election to use asset depreciation range system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... depreciation range system. 1.167(l)-4 Section 1.167(l)-4 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT... Individuals and Corporations § 1.167(l)-4 Public utility property; election to use asset depreciation range system. (a) Application of section 167(l) to certain property subject to asset depreciation range...

  7. 26 CFR 1.167(l)-4 - Public utility property; election to use asset depreciation range system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... depreciation range system. 1.167(l)-4 Section 1.167(l)-4 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT... Individuals and Corporations § 1.167(l)-4 Public utility property; election to use asset depreciation range system. (a) Application of section 167(l) to certain property subject to asset depreciation range...

  8. Can observations inside the Solar System reveal the gravitational properties of the quantum vacuum?

    NASA Astrophysics Data System (ADS)

    Hajdukovic, Dragan Slavkov

    2013-02-01

    The understanding of the gravitational properties of the quantum vacuum might be the next scientific revolution. It was recently proposed that the quantum vacuum contains the virtual gravitational dipoles; we argue that this hypothesis might be tested within the Solar System. The key point is that the quantum vacuum ("enriched" with the gravitational dipoles) induces a retrograde precession of the perihelion. It is obvious that this phenomenon might eventually be revealed by more accurate studies of orbits of planets and orbits of the artificial Earth satellites. However, we suggest that potentially the best "laboratory" for the study of the gravitational properties of the quantum vacuum is the recently discovered dwarf planet Eris with its satellite named Dysnomia; the distance of nearly 100 AU from the Sun makes it the unique system in which the precession of the perihelion of Dysnomia (around Eris) is strongly dominated by the quantum vacuum.

  9. Solvent effects on the optical properties of two-level systems with permanent dipole moments

    NASA Astrophysics Data System (ADS)

    Mastrodomenico, A.; Izquierdo, M. A.; Paz, J. L.; Colmenares, P.

    2013-11-01

    The inclusion of the permanent dipole moments and the solvent on the optical conventional Bloch equations (OCBE) allowed us to obtain analytical expressions for the optical properties of a two-level molecular system. We employed the methodology developed by Colmenares et al.1, in which they model the collisional effect of the solvent through a stochastical function, ξ(t) = ω0 + σ(t), so the OCBE become a set of coupled integro-differential stochastical equations that we solved, up to third order in the incident field, employing the perturbation theory. Once obtained the analytical expressions for the density matrix elements, macroscopic polarization and effective susceptibility of the system, we studied the optical properties derived in the frequency space, inside and outside the rotating wave approximation.

  10. Synthesis and optical properties of isomeric branched pi-conjugated systems.

    PubMed

    Nierengarten, Jean-François; Zhang, Sheng; Gégout, Aline; Urbani, Maxence; Armaroli, Nicola; Marconi, Giancarlo; Rio, Yannick

    2005-09-16

    [structure: see text] Branched conjugated systems with a terminal alkyne function have been prepared starting from 4-(triisopropylsilylethynyl) phenylacetylene by applying the following iterative reaction sequence: (i) metal-catalyzed cross-coupling reaction of the terminal alkyne with 3,4-dibromobenzaldehyde or 2,5- dibromobenzaldehyde; (ii) Corey-Fuchs dibromoolefination and treatment with an excess of LDA. The building blocks thus prepared have been subjected to a Pd-catalyzed cross-coupling reaction with 1,4-diiodobenzene to yield isomeric branched pi-conjugated systems containing 7 (first generation) or 15 (second generation) phenyl units connected by ethynyl spacers. The different pi-conjugation patterns in those isomeric derivatives have a dramatic effect on their electronic properties, as attested by the differences observed in their absorption and emission spectra. Finally, theoretical calculations have been performed to rationalize the optical properties of these compounds.

  11. Evolutionary associations between nectar properties and specificity in bird pollination systems.

    PubMed

    Johnson, Steven D; Nicolson, Susan W

    2008-02-23

    A long-standing paradigm in biology has been that hummingbirds and passerine birds select for different nectar properties in the plants they pollinate. Here we show that this dichotomy is false and a more useful distinction is that between specialized and generalized bird pollination systems. Flowers adapted for sunbirds, which are specialized passerine nectarivores, have nectar similar to that of hummingbird flowers in terms of volume (approx. 10-30 microl), concentration (approx. 15-25% w/w) and sucrose content (approx. 40-60% of total sugar). In contrast, flowers adapted to generalized bird pollinators are characterized by large volumes (approx. 40-100 microl) of extremely dilute (approx. 8-12%) nectar with minimal sucrose (approx. 0-5%). These differences in nectar traits are highly significant even when statistical analyses are based on phylogenetically separate pairwise comparisons between taxa. We present several hypotheses for the association between nectar properties and specificity in bird pollination systems.

  12. System and methods to determine and monitor changes in microstructural properties

    DOEpatents

    Turner, Joseph Alan

    2011-05-17

    A system and methods with which changes in microstructure properties such as grain size, grain elongation, texture, and porosity of materials can be determined and monitored over time to assess conditions such as stress and defects. The present invention includes a database of data, wherein a first set of data is used for comparison with a second set of data to determine the conditions of the material microstructure.

  13. Effect of defoliant (butiphose) on morpho-physiological properties and enzyme systems of natural membranes.

    PubMed

    Mirakhmedov, A K; Ochilov, K R; Sagatova, G A; Khan, M Z; Khole, V

    1989-03-01

    Butiphose (Tributyltritiophosphate, (C4H9S)3PO) a commonly used defoliant in cotton growing regions of USSR, caused extensive alterations in morphological features of erythrocyte and nuclear membranes and affected the permeability properties of rat liver mitochondrial membrane. It disrupted Ca2+ transport system and other energy dependent processes in mitochondria. A reduction in the activity of cytochrome-c-oxidase and NAD.H-oxidase was also observed.

  14. ON THE COMPLETENESS AND QUASIPOWER BASIS PROPERTY OF SYSTEMS \\{z^nf(\\lambda_nz)\\}

    NASA Astrophysics Data System (ADS)

    Oskolkov, V. A.

    1990-02-01

    This paper discusses questions of completeness and the quasipower property in spaces A_R of systems of functions \\{z^nf(\\lambda_nz)\\} under some natural conditions on the Taylor coefficients of the function f(z), assumed regular in a disk \\vert z\\vert. The complex numbers \\lambda_n ( n=0,1,\\dots) are subject to the condition \\vert\\lambda_n\\vert\\leqslant1. Bibliography: 8 titles.

  15. Lactones. 21. Synthesis and odoriferous properties of lactones with the p-menthane system.

    PubMed

    Dams, Iwona; Bialoniska, Agata; Ciunik, Zbigniew; Wawrzenczyk, Czesław

    2004-03-24

    Starting from (R)-(+)- and (S)-(-)-pulegone, enantiomeric pairs of esters and lactones with the p-menthane system were obtained. The Claisen rearrangement of allylic alcohols and iodolactonization of gamma,delta-unsaturated acids were the key steps of syntheses presented. The structures of compounds were determined by both spectroscopic and crystallographic methods. Some of the synthesized compounds are characterized by interesting odoriferous properties.

  16. Comparing the properties of neuronal culture systems: a shopping guide for the cell biologist.

    PubMed

    Hollenbeck, Peter J; Bamburg, James R

    2003-01-01

    Cell biologists of many stripes may find that their question of interest can be studied to advantage in neurons. However, they will also find that "neurons" include many and diverse cell types among which perhaps just one or a few may be ideal for a particular experiment. This chapter discusses the properties, relative complexity, and cost of primary neurons and neuronal cell types from different species and parts of the nervous system and compares their utility for different kinds of cell biological experiments.

  17. Properties of solutions of certain control problems associated with the Navier-Stokes system

    NASA Astrophysics Data System (ADS)

    Fursikov, A. V.

    The paper examines the properties of solutions of certain problems involving the control of systems described by the Navier-Stokes equations with periodic boundary conditions and without constraints on the controlling parameter. The uniqueness of the solutions is considered; necessary and sufficient conditions of the absolute minimum are obtained; and the smoothness of the solutions is demonstrated. The corresponding Euler-Lagrange equations are also examined.

  18. Soil food web properties explain ecosystem services across European land use systems

    PubMed Central

    de Vries, Franciska T.; Thébault, Elisa; Liiri, Mira; Birkhofer, Klaus; Tsiafouli, Maria A.; Bjørnlund, Lisa; Bracht Jørgensen, Helene; Brady, Mark Vincent; Christensen, Søren; de Ruiter, Peter C.; d’Hertefeldt, Tina; Frouz, Jan; Hedlund, Katarina; Hemerik, Lia; Hol, W. H. Gera; Hotes, Stefan; Mortimer, Simon R.; Setälä, Heikki; Sgardelis, Stefanos P.; Uteseny, Karoline; van der Putten, Wim H.; Wolters, Volkmar; Bardgett, Richard D.

    2013-01-01

    Intensive land use reduces the diversity and abundance of many soil biota, with consequences for the processes that they govern and the ecosystem services that these processes underpin. Relationships between soil biota and ecosystem processes have mostly been found in laboratory experiments and rarely are found in the field. Here, we quantified, across four countries of contrasting climatic and soil conditions in Europe, how differences in soil food web composition resulting from land use systems (intensive wheat rotation, extensive rotation, and permanent grassland) influence the functioning of soils and the ecosystem services that they deliver. Intensive wheat rotation consistently reduced the biomass of all components of the soil food web across all countries. Soil food web properties strongly and consistently predicted processes of C and N cycling across land use systems and geographic locations, and they were a better predictor of these processes than land use. Processes of carbon loss increased with soil food web properties that correlated with soil C content, such as earthworm biomass and fungal/bacterial energy channel ratio, and were greatest in permanent grassland. In contrast, processes of N cycling were explained by soil food web properties independent of land use, such as arbuscular mycorrhizal fungi and bacterial channel biomass. Our quantification of the contribution of soil organisms to processes of C and N cycling across land use systems and geographic locations shows that soil biota need to be included in C and N cycling models and highlights the need to map and conserve soil biodiversity across the world. PMID:23940339

  19. A data acquisition system for longitudinal beam properties in a rapid cycling synchrotron

    SciTech Connect

    Steimel, J.; Tan, C.Y.; /Fermilab

    2011-03-01

    A longitudinal beam properties, data acquisition system has been commissioned to operate in the Fermilab booster ring. This system captures real time information including beam synchronous phase, bunch length, and coupled bunch instability amplitudes as the beam is accelerated from 400 MeV to 8 GeV in 33 ms. The system uses an off-the-shelf Tektronix oscilloscope running Labview software and a synchronous pulse generator. This paper describes the hardware configuration and the software configuration used to optimize the data processing rate. The Fermilab Booster is currently pushed to its intensity limit due to the high demand from different experiments for protons. This will continue into the era of the intensity frontier. While intensity is the most critical parameter, emittance must be controlled as well. Longitudinal emittance is an important parameter for optimizing the slip stacking process in the Main Injector. Longitudinal instabilities can spoil the emittance, so it is important to monitor bunch lengths and bunch phase oscillations in the Booster. The Booster presents a special challenge when it comes to measuring beam properties. The acceleration ramp is short (33ms), and the RF frequency varies from 38-52.8 MHz. Standard instrumentation like spectrum analyzers and network analyzers cannot effectively measure beam properties, because they cannot track the changing frequencies. Early instrumentation involved a series of tracking oscillators, mixers, and diode detectors that would require vigilant calibration. There was a demand for a more robust means of gathering beam parameters.

  20. Soil food web properties explain ecosystem services across European land use systems.

    PubMed

    de Vries, Franciska T; Thébault, Elisa; Liiri, Mira; Birkhofer, Klaus; Tsiafouli, Maria A; Bjørnlund, Lisa; Bracht Jørgensen, Helene; Brady, Mark Vincent; Christensen, Søren; de Ruiter, Peter C; d'Hertefeldt, Tina; Frouz, Jan; Hedlund, Katarina; Hemerik, Lia; Hol, W H Gera; Hotes, Stefan; Mortimer, Simon R; Setälä, Heikki; Sgardelis, Stefanos P; Uteseny, Karoline; van der Putten, Wim H; Wolters, Volkmar; Bardgett, Richard D

    2013-08-27

    Intensive land use reduces the diversity and abundance of many soil biota, with consequences for the processes that they govern and the ecosystem services that these processes underpin. Relationships between soil biota and ecosystem processes have mostly been found in laboratory experiments and rarely are found in the field. Here, we quantified, across four countries of contrasting climatic and soil conditions in Europe, how differences in soil food web composition resulting from land use systems (intensive wheat rotation, extensive rotation, and permanent grassland) influence the functioning of soils and the ecosystem services that they deliver. Intensive wheat rotation consistently reduced the biomass of all components of the soil food web across all countries. Soil food web properties strongly and consistently predicted processes of C and N cycling across land use systems and geographic locations, and they were a better predictor of these processes than land use. Processes of carbon loss increased with soil food web properties that correlated with soil C content, such as earthworm biomass and fungal/bacterial energy channel ratio, and were greatest in permanent grassland. In contrast, processes of N cycling were explained by soil food web properties independent of land use, such as arbuscular mycorrhizal fungi and bacterial channel biomass. Our quantification of the contribution of soil organisms to processes of C and N cycling across land use systems and geographic locations shows that soil biota need to be included in C and N cycling models and highlights the need to map and conserve soil biodiversity across the world.

  1. Participation in Decision Making as a Property of Complex Adaptive Systems: Developing and Testing a Measure

    PubMed Central

    Anderson, Ruth A.; Hsieh, Pi-Ching; Su, Hui Fang; Landerman, Lawrence R.; McDaniel, Reuben R.

    2013-01-01

    Objectives. To (1) describe participation in decision-making as a systems-level property of complex adaptive systems and (2) present empirical evidence of reliability and validity of a corresponding measure. Method. Study 1 was a mail survey of a single respondent (administrators or directors of nursing) in each of 197 nursing homes. Study 2 was a field study using random, proportionally stratified sampling procedure that included 195 organizations with 3,968 respondents. Analysis. In Study 1, we analyzed the data to reduce the number of scale items and establish initial reliability and validity. In Study 2, we strengthened the psychometric test using a large sample. Results. Results demonstrated validity and reliability of the participation in decision-making instrument (PDMI) while measuring participation of workers in two distinct job categories (RNs and CNAs). We established reliability at the organizational level aggregated items scores. We established validity of the multidimensional properties using convergent and discriminant validity and confirmatory factor analysis. Conclusions. Participation in decision making, when modeled as a systems-level property of organization, has multiple dimensions and is more complex than is being traditionally measured. Managers can use this model to form decision teams that maximize the depth and breadth of expertise needed and to foster connection among them. PMID:24349771

  2. Relevance of system size to the steady-state properties of tapped granular systems.

    PubMed

    Gago, Paula A; Maza, Diego; Pugnaloni, Luis A

    2015-03-01

    We investigate the steady-state packing fraction ϕ and force moment tensor Σ of quasi-two-dimensional granular columns subjected to tapping. Systems of different height h and width L are considered. We find that ϕ and Σ, which describe the macroscopic state of the system, are insensitive to L for L>50d (with d the grain diameter). However, results for granular columns of different heights cannot be conciliated. This suggests that comparison between results of different laboratories on this type of experiments can be done only for systems of same height. We show that a parameter ɛ=1+(Aω)2/(2gh), with A and ω the amplitude and frequency of the tap and g the acceleration of gravity, can be defined to characterize the tap intensity. This parameter is based on the effective flight of the granular bed, which takes into account the h dependency. When ϕ is plotted as a function of ɛ, the data collapses for systems of different h. However, this parameter alone is unable to determine the steady state to be reached since different Σ can be observed for a given ɛ if different column heights are considered.

  3. Conservation properties of numerical integration methods for systems of ordinary differential equations

    NASA Technical Reports Server (NTRS)

    Rosenbaum, J. S.

    1976-01-01

    If a system of ordinary differential equations represents a property conserving system that can be expressed linearly (e.g., conservation of mass), it is then desirable that the numerical integration method used conserve the same quantity. It is shown that both linear multistep methods and Runge-Kutta methods are 'conservative' and that Newton-type methods used to solve the implicit equations preserve the inherent conservation of the numerical method. It is further shown that a method used by several authors is not conservative.

  4. RIM as the data base management system for a material properties data base

    NASA Technical Reports Server (NTRS)

    Karr, P. H.; Wilson, D. J.

    1984-01-01

    Relational Information Management (RIM) was selected as the data base management system for a prototype engineering materials data base. The data base provides a central repository for engineering material properties data, which facilitates their control. Numerous RIM capabilities are exploited to satisfy prototype data base requirements. Numerical, text, tabular, and graphical data and references are being stored for five material types. Data retrieval will be accomplished both interactively and through a FORTRAN interface. The experience gained in creating and exercising the prototype will be used in specifying requirements for a production system.

  5. The study of data collection method for the plasma properties collection and evaluation system from web

    NASA Astrophysics Data System (ADS)

    Park, Jun-Hyoung; Song, Mi-Young; Plasma Fundamental Technology Research Team

    2015-09-01

    Plasma databases are necessarily required to compute the plasma parameters and high reliable databases are closely related with accuracy enhancement of simulations. Therefore, a major concern of plasma properties collection and evaluation system is to create a sustainable and useful research environment for plasma data. The system has a commitment to provide not only numerical data but also bibliographic data (including DOI information). Originally, our collection data methods were done by manual data search. In some cases, it took a long time to find data. We will be find data more automatically and quickly than legacy methods by crawling or search engine such as Lucene.

  6. Noncontact single-pulse optical method to measure interfacial properties in intact systems.

    PubMed

    Clark, David C; Kim, Myung K

    2012-12-15

    We introduce a noncontact purely optical approach to measuring the localized surface properties of an interface within a system using a single optical pressure pulse and a time-resolved digital holographic quantitative phase-imaging technique to track the propagating nanometric capillary disturbance. We demonstrate the proposed method's ability to measure the surface energy of deionized water, methanol, and chemical monolayers formed by surfactants with good agreement to published values. The development of this technique boasts immediate application to static and dynamic systems and near-future applications for living biological cell membranes.

  7. Evaluation of optical and chromatic properties under electrical and thermal coupling in solid state lighting systems

    NASA Astrophysics Data System (ADS)

    Fu, Han-Kuei; Peng, Yi-Ping; Wang, Chien-Ping; Chiang, Hsin-Chien; Chen, Tzung-Te; Chen, Chiu-Ling; Chou, Pei-Ting

    2013-09-01

    For energy-saving, high efficiency and low pollution, the lighting of LED systems is important for the future of green energy technology industry. The solid state lighting becomes the replacement of traditional lighting, such as, light bulbs and compact fluorescent lamps. Because of the semiconductor characteristics, the luminous efficiency of LEDs is sensitive to the operating temperature. Besides increasing the luminous efficiency, effective controlling electricity and thermal characteristics in the design of LED lighting products is the key point to achieve the best results. LED modules can be combined with multi-grain process or through a combination of multiple LED chips. Accurate analysis of this LED module for the electrical, thermal characteristics and high reliability is the critical knowledge of modular design. In this report, we studied the electrical and thermal coupling phenomenon in solid state lighting systems to analyze their reliability. By experiments and simulations, we obtained the apparent variation of temperature distribution of LED system due to differences of their forward voltages and thermal resistances. These events may reduce their reliability. Besides, the evaluation of optical and chromatic properties was based on the variation of temperature distribution and current of LED system. This is the key technology to predict the optical and chromatic properties of LED system in use.

  8. VizieR Online Data Catalog: Properties of Kepler multi-planet candidate systems (Wang+, 2014)

    NASA Astrophysics Data System (ADS)

    Wang, J.; Xie, J.-W.; Barclay, T.; Fischer, D. A.

    2016-05-01

    Our sample consists of bright host stars with multi-planet transiting systems from Kepler. Out of 5779 Kepler Objects of Interest (http://exoplanetarchive.ipac.caltech.edu/), we selected all the systems with a Kepler magnitude (KP) brighter than 13.5mag and with at least two planet candidates. The sample includes 343 planet candidates (see Table3) in 138 multi-planet candidate systems (see Table2) from the Kepler mission. For these systems, we used archival data from Kepler to characterize their stellar (see Table2) and orbital properties (see Table3). We used UKIRT images to calculate brightness contrast curves and to detect stellar companions around planet candidate host stars (see Table4). (3 data files).

  9. Newly Designed Tensile Test System for in vitro Measurement of Mechanical Properties of Cytoskeletal Filaments

    NASA Astrophysics Data System (ADS)

    Deguchi, Shinji; Ohashi, Toshiro; Sato, Masaaki

    A tensile test system for isolated cytoskeletal filaments, which enables to control strain rate, was newly designed. A pair of piezo-driven cantilevers were used to manipulate the specimen and to measure tensile load from the deflection of one of the cantilevers. The displacements of the cantilevers were optically and electrically detected. The specimen strain, determined from the cantilever displacements, was used as a feedback signal. We proposed a servo-system for strain rate control in which a desired path for the strain transition was designated. The path was chosen as a triangular-shape waveform against time, along which the strain rate is kept constant. We measured tensile properties of a single stress fiber isolated from a smooth muscle cell with this system to obtain a stretching stiffness of 45nN per strain. Performance evaluation and the tensile test demonstrated that the system enabled to carry out strain rate-controlled tensile test.

  10. Stability and dynamical properties of material flow systems on random networks

    NASA Astrophysics Data System (ADS)

    Anand, K.; Galla, T.

    2009-04-01

    The theory of complex networks and of disordered systems is used to study the stability and dynamical properties of a simple model of material flow networks defined on random graphs. In particular we address instabilities that are characteristic of flow networks in economic, ecological and biological systems. Based on results from random matrix theory, we work out the phase diagram of such systems defined on extensively connected random graphs, and study in detail how the choice of control policies and the network structure affects stability. We also present results for more complex topologies of the underlying graph, focussing on finitely connected Erdös-Réyni graphs, Small-World Networks and Barabási-Albert scale-free networks. Results indicate that variability of input-output matrix elements, and random structures of the underlying graph tend to make the system less stable, while fast price dynamics or strong responsiveness to stock accumulation promote stability.

  11. Physics of Life: A Model for Non-Newtonian Properties of Living Systems

    NASA Technical Reports Server (NTRS)

    Zak, Michail

    2010-01-01

    This innovation proposes the reconciliation of the evolution of life with the second law of thermodynamics via the introduction of the First Principle for modeling behavior of living systems. The structure of the model is quantum-inspired: it acquires the topology of the Madelung equation in which the quantum potential is replaced with the information potential. As a result, the model captures the most fundamental property of life: the progressive evolution; i.e. the ability to evolve from disorder to order without any external interference. The mathematical structure of the model can be obtained from the Newtonian equations of motion (representing the motor dynamics) coupled with the corresponding Liouville equation (representing the mental dynamics) via information forces. All these specific non-Newtonian properties equip the model with the levels of complexity that matches the complexity of life, and that makes the model applicable for description of behaviors of ecological, social, and economical systems. Rather than addressing the six aspects of life (organization, metabolism, growth, adaptation, response to stimuli, and reproduction), this work focuses only on biosignature ; i.e. the mechanical invariants of life, and in particular, the geometry and kinematics of behavior of living things. Living things obey the First Principles of Newtonian mechanics. One main objective of this model is to extend the First Principles of classical physics to include phenomenological behavior on living systems; to develop a new mathematical formalism within the framework of classical dynamics that would allow one to capture the specific properties of natural or artificial living systems such as formation of the collective mind based upon abstract images of the selves and non-selves; exploitation of this collective mind for communications and predictions of future expected characteristics of evolution; and for making decisions and implementing the corresponding corrections if

  12. Rheological Properties of Silica Nanoparticles in Brine and Brine-Surfactant Systems

    NASA Astrophysics Data System (ADS)

    Pales, Ashley; Kinsey, Erin; Li, Chunyan; Mu, Linlin; Bai, Lingyun; Clifford, Heather; Darnault, Christophe

    2016-04-01

    Rheological Properties of Silica Nanoparticles in Brine and Brine-Surfactant Systems Ashley R. Pales, Erin Kinsey, Chunyan Li, Linlin Mu, Lingyun Bai, Heather Clifford, and Christophe J. G. Darnault Department of Environmental Engineering and Earth Sciences, Laboratory of Hydrogeoscience and Biological Engineering, L.G. Rich Environmental Laboratory, Clemson University, Clemson, SC, USA Nanofluids are suspensions of nanometer sized particles in any fluid base, where the nanoparticles effect the properties of the fluid base. Commonly, nanofluids are water based, however, other bases such as ethylene-glycol, glycerol, and propylene-glycol, have been researched to understand the rheological properties of the nanofluids. This work aims to understand the fundamental rheological properties of silica nanoparticles in brine based and brine-surfactant based nanofluids with temperature variations. This was done by using variable weight percent of silica nanoparticles from 0.001% to 0.1%. Five percent brine was used to create the brine based nanofluids; and 5% brine with 2CMC of Tween 20 nonionic surfactant (Sigma-Aldrich) was used to create the brine-surfactant nanofluid. Rheological behaviors, such as shear rate, shear stress, and viscosity, were compared between these nanofluids at 20C and at 60C across the varied nanoparticle wt%. The goal of this work is to provide a fundamental basis for future applied testing for enhanced oil recovery. It is hypothesized that the addition of surfactant will have a positive impact on nanofluid properties that will be useful for enhance oil recovery. Differences have been observed in preliminary data analysis of the rheological properties between these two nanofluids indicating that the surfactant is having the hypothesized effect.

  13. The DIGISOIL multi-sensor system: from geophysical measurements to soil properties.

    NASA Astrophysics Data System (ADS)

    Grandjean, Gilles

    2010-05-01

    The purposes of the multidisciplinary DIGISOIL project are the integration and improvement of in situ and proximal measurement technologies for the assessment of soil properties and soil degradation indicators, going from the sensing technologies to their integration and their application in (digital) soil mapping (DSM). In order to assess and prevent soil degradation and to benefit from the different ecological, economical and historical functions of the soil in a sustainable way, high resolution and quantitative maps of soil properties are needed. The core objective of the project is to explore and exploit new capabilities of advanced geophysical technologies for answering this societal demand. To this aim, DIGISOIL addresses four issues covering technological, soil science and economic aspects: (i) the validation of geophysical (in situ, proximal and airborne) technologies and integrated pedo-geophysical inversion techniques (mechanistic data fusion) (ii) the relation between the geophysical parameters and the soil properties, (iii) the integration of the derived soil properties for mapping soil functions and soil threats, (iv) the pre-evaluation, standardisation and sub-industrialization of the proposed methodologies, including technical and economical studies related to the societal demand. With respect to these issues, the preliminary tasks of the DIGISOIL project were to develop, test and validate the most relevant geophysical technologies for mapping soil properties. The different field tests, realized at this time, allow focusing on technological suitable solutions for each of the identified methods: geoelectric, GPR, EMI, seismics, magnetic and hyperspectral. After data acquisition systems, sensor geometry, and advanced data processing techniques have been developed and validated, we present now the solutions for going from such data to soil properties maps.

  14. Contrasting Inherent Optical Properties and Carbon Metabolism Between Five Northeastern (USA) Estuary-plume Systems

    NASA Technical Reports Server (NTRS)

    Vandemark, Doug; Salisbury, Joe; Hunt, Chris; McGillis, Wade R.

    2004-01-01

    We have recently developed the ability to rapidly assess Surface inherent optical properties (IOP), oxygen concentration and pCO2 in estuarine-plume systems using flow-through instrumentation. During the summer of 2004, several estuarine-plume systems were surveyed which include the Pleasant (ME), Penobscot (ME), Kennebec-Androscoggin (ME), Merrimack (NH-MA) and Hudson (NY). Continuous measurements of surface chlorophyll and colored dissolved organic carbon (CDOM) fluorescence, beam attenuation, temperature, salinity, oxygen and pC02 were taken at each system along a salinity gradient from fresh water to near oceanic endmembers. CTD and IOP profiles were also taken at predetermined surface salinity intervals. These were accompanied by discrete determinations of chlorophyll (HPLC and fluorometric), total suspended solids (TSS), dissolved organic carbon (DOC) and alkalinity. IOP data were calibrated using chlorophyll, DOC and TSS data to enable the retrieval of these constituents from IOP data. Considerable differences in the data sets were observed between systems. These ranged from the DOC-enriched, strongly heterotrophic Pleasant River System to the high-chlorophyll autotrophic Merrimack River System. Using pCO2 and oxygen saturation measurements as proxies for water column metabolism, distinct relationships were found between trophic status and inherent optical properties. The nature of these relationships varies between systems and is likely a function of watershed and estuarine attributes including carbon and nutrient loading, in-situ production and related autochthonous inputs of DOC and alkalinity. Our results suggest that IOP data may contain significant information about the trophic status of estuarine and plume systems.

  15. Atomically modified thin interface in metal-dielectric hetero-integrated systems: control of electronic properties.

    PubMed

    Iida, Kenji; Nobusada, Katsuyuki

    2017-04-12

    We have performed first-principles studies of the electronic properties of Cu-diamond hetero-integrated systems, particularly placing emphasis on elucidating the effects of surface modification of diamond with H or O. It is found that the electronic properties crucially depend on the chemical compositions of the modified atomically thin interface region. The local density of states (LDOS) of the H-terminated diamond moiety near the Cu surface exhibits a clearly different distribution from that near the vacuum region, whereas the LDOS of the O-terminated diamond is almost independent of the Cu deposition. In other words, the effects of the electronic interactions between Cu and diamond on the electronic properties in the interface region are readily controlled by surface modification with only one atomic (i.e. H or O) layer. Electric field (EF) effects on the Cu-diamond systems also strongly depend on the electronic details, i.e. atomistic modification in the interface regions. In particular, at the interface between the H-terminated diamond moiety and the vacuum region, its conduction band energy is strongly affected by an applied EF much more than the valence band energy; that is, the band gap can be varied with an applied EF. The band gap variation is found to be attributed to an atomistic level difference in the spatial extension of the valence and conduction bands and thus is not explained with a macroscopic band diagram model. It has been demonstrated that the electronic properties of hetero-integrated systems are described and controlled well by carefully designing atomically thin interface regions.

  16. Atomically modified thin interface in metal-dielectric hetero-integrated systems: control of electronic properties

    NASA Astrophysics Data System (ADS)

    Iida, Kenji; Nobusada, Katsuyuki

    2017-04-01

    We have performed first-principles studies of the electronic properties of Cu-diamond hetero-integrated systems, particularly placing emphasis on elucidating the effects of surface modification of diamond with H or O. It is found that the electronic properties crucially depend on the chemical compositions of the modified atomically thin interface region. The local density of states (LDOS) of the H-terminated diamond moiety near the Cu surface exhibits a clearly different distribution from that near the vacuum region, whereas the LDOS of the O-terminated diamond is almost independent of the Cu deposition. In other words, the effects of the electronic interactions between Cu and diamond on the electronic properties in the interface region are readily controlled by surface modification with only one atomic (i.e. H or O) layer. Electric field (EF) effects on the Cu-diamond systems also strongly depend on the electronic details, i.e. atomistic modification in the interface regions. In particular, at the interface between the H-terminated diamond moiety and the vacuum region, its conduction band energy is strongly affected by an applied EF much more than the valence band energy; that is, the band gap can be varied with an applied EF. The band gap variation is found to be attributed to an atomistic level difference in the spatial extension of the valence and conduction bands and thus is not explained with a macroscopic band diagram model. It has been demonstrated that the electronic properties of hetero-integrated systems are described and controlled well by carefully designing atomically thin interface regions.

  17. First results of the DIGISOIL multi-sensor system for mapping soil properties

    NASA Astrophysics Data System (ADS)

    Grandjean, G.

    2009-04-01

    The purposes of the multidisciplinary DIGISOIL project are the integration and improvement of in situ and proximal measurement technologies for the assessment of soil properties and soil degradation indicators, going from the sensing technologies to their integration and their application in (digital) soil mapping (DSM). In order to assess and prevent soil degradation and to benefit from the different ecological, economical and historical functions of the soil in a sustainable way, high resolution and accurate maps of soil properties are needed. The core objective of the project is to explore and exploit new capabilities of advanced geophysical technologies for answering this societal demand. To this aim, DIGISOIL addresses four issues covering technological, soil science and economic aspects (Figure 1): (i) the validation of geophysical (in situ, proximal and airborne) technologies and integrated pedo-geophysical inversion techniques (mechanistic data fusion) (ii) the relation between the geophysical parameters and the soil properties, (iii) the integration of the derived soil properties for mapping soil functions and soil threats, (iv) the evaluation, standardisation and sub-industrialization of the proposed methodologies, including technical and economical studies. With respect to these issues, the preliminary tasks of the DIGISOIL project were to develop, test and validate the most relevant geophysical technologies for mapping soil properties. The different field tests, realized at this time, allow focusing on technological suitable solutions for each of identified methods: geoelectric, GPR, seismics, magnetic and hyperspectral. Data acquisition systems, sensor geometry, data processing are thus presented and discussed in the perspectives of producing information layers for Digital Soil Mapping. Next tasks will be dedicated to (i) establish correlations between the measured geophysical measurements and the soil properties involved in soil functions / threats

  18. Mechanical properties of polymer/carbon nanotube composite micro-electromechanical systems bridges

    NASA Astrophysics Data System (ADS)

    Sousa, P. M.; Chu, V.; Conde, J. P.

    2013-04-01

    Microelectromechanical systems with all-polymer structural layers are expected to allow novel MEMS applications due to their mechanical, optical, electronic, and chemical properties, which are tunable and distinct from the standard inorganic layers currently used. The mechanical properties of micro-electromechanical bridge resonators (pMEMS) based on a polymer/carbon-nanotubes (CNT) composite structural material are presented. The structural material of the electrostatically actuated pMEMS microresonators are multilayers of a conductive polymer based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) to which carboxylated multi-wall CNTs monolayers are electrostatically attached after surface functionalization. The effects of measurement pressure, temperature, and applied load on the resonance frequency and on the quality factor, Q, of the pMEMS are studied. The long term reliability of the pMEMS resonators is also investigated, and the resonators were subjected to above 1011 actuation cycles without significant performance deterioration. The mechanical properties of the pMEMS are systematically compared to those of a doped hydrogenated amorphous silicon (n+-a-Si:H) MEMS. While the CNT multilayers increase the rigidity (and hence the resonance frequency) as well as the electrical conductivity of the structural layer, they decrease the energy dissipation (and hence increase Q). Changes in CNT-polymer matrix adhesion result in reversible changes of the resonator properties during operation, requiring monitoring and control.

  19. The boron oxide{endash}boric acid system: Nanoscale mechanical and wear properties

    SciTech Connect

    Ma, X.; Unertl, W.N.; Erdemir, A.

    1999-08-01

    The film that forms spontaneously when boron oxide (B{sub 2}O{sub 3}) is exposed to humid air is a solid lubricant. This film is usually assumed to be boric acid (H{sub 3}BO{sub 3}), the stable bulk phase. We describe the nanometer-scale surface morphology, mechanical properties, and tribological properties of these films and compare them with crystals precipitated from saturated solutions of boric acid. Scanning force microscopy (SFM) and low-load indentation were the primary experimental tools. Mechanical properties and their variation with depth are reported. In all cases, the surfaces were covered with a layer that has different mechanical properties than the underlying bulk. The films formed on boron oxide showed no evidence of crystalline structure. A thin surface layer was rapidly removed, followed by slower wear of the underlying film. The thickness of this initial layer was sensitive to sample preparation conditions, including humidity. Friction on the worn surface was lower than on the as-formed surface in all cases. In contrast, the SFM tip was unable to cause any wear to the surface film on the precipitated crystals. Indentation pop-in features were common for precipitated crystals but did not occur on the films formed on boron oxide. The surface structures were more complex than assumed in models put forth previously to explain the mechanism of lubricity in the boron oxide{endash}boric acid{endash}water system. {copyright} {ital 1999 Materials Research Society.}

  20. 4d electron Ruthenate systems: their unique and new magnetic properties

    NASA Astrophysics Data System (ADS)

    Lee, Seungran; Shin, Yeongjae; Anwar, M. S.; Sugimoto, Yusuke; Lee, Mincheol; Kang, Sungjin; Yonezawa, Shingo; Maeno, Yoshiteru; Noh, Taewon

    The Ruddlesden-Popper series (PR) of Srn+1RunO3n+1 has attract much interest of their unique physical properties. Among them, SrRuO3 (n = ∞) (SRO) is the only ferromagnetic metallic oxide especially in Ru 4d transition metal oxides. Bulk SRO has orthorhombic structure showing the Curie temperature (TC) ~ 160 K. It is well known that RuO6 octahedral distortion plays critical roles in its mangetic properties. In film systems, such RuO6 octahedra can be easily controlled by strain-engineering. In this talk, with high quality SRO films fully strained (-1.7%-1%) using various substrates, we systematically studied their structural changes and associated magnetic properties. Compared to theoretical predictions, the structural changes can be explained, while the magnetic property changes cannot be understood. Surprisingly, when SRO113 is grown on its PR series of Sr2RuO4 (n=1) (SRO214) single crystal, the exact substrate of SRO214 magnetization results in strongly enhanced magnetization (M > 3 μB/Ru, TC ~ 160 K), which has never found SRO113 (001) since the low-spin configuration of SRO113 prevent M never exceed 2 μB/Ru. The mystery of M in SRO113 (especially SRO113/SRO214) will be further discussed.

  1. Physical properties of a two-component system at the Fermi and Sharvin length scales

    NASA Astrophysics Data System (ADS)

    Armstrong, Jason N.; Gande, Eric M.; Vinti, John W.; Hua, Susan Z.; Deep Chopra, Harsh

    2012-11-01

    Previously, we have reported the measurement of various physical properties at the Fermi and Sharvin length scales in pure elements (1-component systems). In the present study, the evolution of physical properties is mapped in a 2-component system at these length scales, using Au-Ag alloys. These alloys are well known to have complete solubility in each other at all compositions in the bulk and an ideal system to vary the surface energy of the alloy simply by changing the alloy composition. At sample sizes where surface effects dominate (less than ˜2-3 nm), varying the alloy composition is found to cause dramatic changes in force required to rupture the bonds (strength) as well as atomic cohesion (modulus) and can be directly attributed to segregation of higher surface energy Au from the lower surface energy Ag. In other words, the Au-Ag system with complete solubility in the bulk exhibits segregation at these length scales. This breakdown of bulk solubility rules for alloying (the so-called Hume-Rothery rules) even in near-ideal solid solutions has consequences for future atomic-scale devices.

  2. Physical Properties and Evolution of the Eclipsing Binary System XZ Canis Minoris

    NASA Astrophysics Data System (ADS)

    Poochaum, R.; Komonjinda, S.; Soonthornthum, B.; Rattanasoon, S.

    2010-07-01

    This research aims to study the eclipse binary system so that its physical properties and evolution can be determined and used as an example to teach high school astronomy. The study of an eclipsing binary system XZ Canis Minoris (XZ CMi) was done at Sirindhorn Observatory, Chiang Mai University using a 0.5-meter reflecting telescope with CCD photometric system (2184×1417 pixel) in B V and R bands of UVB System. The data obtained were used to construct the light curve for each wavelength band and to compute the times of its light minima. New elements were derived using observations with linear to all available minima. As a result, linear ephemeris is HDJmin I = .578 808 948+/-0.000 000 121+2450 515.321 26+/-0.001 07 E, and the new orbital period of XZ CMi is 0.578 808 948+/-0.000 000 121 day. The values obtained were used with the previously published times of minima to get O-C curve of XZ CMi. The result revealed that the orbital period of XZ CMi is continuously decreased at a rate of 0.007 31+/-0.000 57 sec/year. This result indicates that the binary stars are moving closer continuously. From the O-C residuals, there is significant change to indicate the existence of the third body or magnetic activity cycle on the star. However, further analysis of the physical properties of XZ CMi is required.

  3. Conductive properties of switchable photoluminescence thermosetting systems based on liquid crystals.

    PubMed

    Tercjak, Agnieszka; Gutierrez, Junkal; Ocando, Connie; Mondragon, Iñaki

    2010-03-16

    Conductive properties of different thermosetting materials modified with nematic 4'-(hexyl)-4-biphenyl-carbonitrile (HBC) liquid crystal and rutile TiO(2) nanoparticles were successfully studied by means of tunneling atomic force miscroscopy (TUNA). Taking into account the liquid crystal state of the HBC at room temperature, depending on both the HBC content and the presence of TiO(2) nanoparticles, designed materials showed different TUNA currents passed through the sample. The addition of TiO(2) nanoparticles into the systems multiply the detected current if compared to the thermosetting systems without TiO(2) nanoparticles and simultaneously stabilized the current passed through the sample, making the process reversible since the absolute current values were almost the same applying both negative and positive voltage. Moreover, thermosetting systems modified with liquid crystals with and without TiO(2) nanoparticles are photoluminescence switchable materials as a function of temperature gradient during repeatable heating/cooling cycle. Conductive properties of switchable photoluminescence thermosetting systems based on liquid crystals can allow them to find potential application in the field of photoresponsive devices, with a high contrast ratio between transparent and opaque states.

  4. Influence of the Ageing Process on the Resistive and Reactive Properties of the Respiratory System

    PubMed Central

    e Tramont, Caio Vinicius Villalón; Faria, Alvaro Camilo Dias; Lopes, Agnaldo José; Jansen, José Manoel; de Melo, Pedro Lopes

    2009-01-01

    INTRODUCTION In an increasingly old society, the study of the respiratory system changes and new techniques dedicated to older patients are of interest in physiologic studies as well as in the diagnosis of respiratory diseases. OBJECTIVES (1) To investigate the impact of ageing on the resistive and reactive properties of the respiratory system, and (2) to compare the easiness of accomplishment of spirometry and forced oscillation for assessing lung function. METHODS We conducted a cross-sectional study in which forced oscillation was used to investigate respiratory system resistive and reactive properties, while spirometry was used as a reference test to evaluate 80 normal subjects aged between 20 and 86 years. A questionnaire was used to evaluate the easiness of accomplishment of spirometry and forced oscillation. RESULTS There was a significant increase in the respiratory system resonance frequency (p<0.003) and a reduction in the mean reactance (p<0.004) with increasing age. Respiratory system resistance and dynamic compliance were not related to the ageing process. The easiness of accomplishment of forced oscillation measurements was greater than that of spirometry. This result was particularly relevant in subjects over 70 years old (p<0.05). CONCLUSIONS Respiratory system resistance and dynamic compliance are not modified with ageing. On the other hand, respiratory system homogeneity decreases during the ageing process. Forced oscillation is easy to perform and provides information complementary to spirometry. This technique may be a promising alternative and/or complement to other conventional exams used to evaluate older people who are unable to adequately perform spirometric tests. PMID:19936180

  5. Osmotic Properties of the Sealed Tubular System of Toad and Rat Skeletal Muscle

    PubMed Central

    Launikonis, Bradley S.; Stephenson, D. George

    2004-01-01

    A method was developed that allows conversion of changes in maximum Ca2+-dependent fluorescence of a fixed amount of fluo-3 into volume changes of the fluo-3–containing solution. This method was then applied to investigate by confocal microscopy the osmotic properties of the sealed tubular (t-) system of toad and rat mechanically skinned fibers in which a certain amount of fluo-3 was trapped. When the osmolality of the myoplasmic environment was altered by simple dilution or addition of sucrose within the range 190–638 mosmol kg−1, the sealed t-system of toad fibers behaved almost like an ideal osmometer, changing its volume inverse proportionally to osmolality. However, increasing the osmolality above 638 to 2,550 mosmol kg−1 caused hardly any change in t-system volume. In myoplasmic solutions made hypotonic to 128 mosmol kg−1, a loss of Ca2+ from the sealed t-system of toad fibers occurred, presumably through either stretch-activated cationic channels or store-operated Ca2+ channels. In contrast to the behavior of the t-system in toad fibers, the volume of the sealed t-system of rat fibers changed little (by <20%) when the osmolality of the myoplasmic environment changed between 210 and 2,800 mosmol kg−1. Results were also validated with calcein. Clear differences between rat and toad fibers were also found with respect to the t-system permeability for glycerol. Thus, glycerol equilibrated across the rat t-system within seconds to minutes, but was not equilibrated across the t-system of toad fibers even after 20 min. These results have broad implications for understanding osmotic properties of the t-system and reversible vacuolation in muscle fibers. Furthermore, we observed for the first time in mammalian fibers an orderly lateral shift of the t-system networks whereby t-tubule networks to the left of the Z-line crossover to become t-tubule networks to the right of the Z-line in the adjacent sarcomere (and vice versa). This orderly rearrangement can

  6. The Experience in Personal Social Systems Questionnaire (EXIS.pers): Development and Psychometric Properties.

    PubMed

    Hunger, Christina; Bornhäuser, Annette; Link, Leoni; Geigges, Julian; Voss, Andreas; Weinhold, Jan; Schweitzer, Jochen

    2017-03-01

    This study presents the theoretical background, development, and psychometric properties of the German and English versions of the Experience in Personal Social Systems Questionnaire (EXIS.pers). It assesses how the members of a personal social system experience their situation within that system. It is designed as a research tool for interventions in which only one member of the system participates (e.g., Family Constellation Seminars). The EXIS.pers was created to measure change on the individual level relating to one's own important personal social system. In Study 1, we used exploratory factor analysis (EFA) for latent variable identification of the original German EXIS.pers (n = 179). In Studies 2 and 3, we used confirmatory factor analysis (CFA) to examine the dimensionality of the German (n = 634) and English (n = 310) EXIS.pers. Internal consistencies and cross-cultural structural equivalence were assessed. EFA indicated that a four-factor model provided best fit for the German EXIS.pers. For both the German and English EXIS.pers, CFA provided the best fit for a five-factor bi-level model that included a general factor (Experience In Personal Social Systems) and four dimensions (Belonging, Autonomy, Accord, Confidence). Good internal consistencies, external associations, and cross-cultural structural equivalence were demonstrated. This study provides first evidence for the German and English EXIS.pers as an economical and reliable measure of an individual's experience within his or her personal social systems.

  7. Statistical distribution of mechanical properties for three graphite-epoxy material systems

    NASA Technical Reports Server (NTRS)

    Reese, C.; Sorem, J., Jr.

    1981-01-01

    Graphite-epoxy composites are playing an increasing role as viable alternative materials in structural applications necessitating thorough investigation into the predictability and reproducibility of their material strength properties. This investigation was concerned with tension, compression, and short beam shear coupon testing of large samples from three different material suppliers to determine their statistical strength behavior. Statistical results indicate that a two Parameter Weibull distribution model provides better overall characterization of material behavior for the graphite-epoxy systems tested than does the standard Normal distribution model that is employed for most design work. While either a Weibull or Normal distribution model provides adequate predictions for average strength values, the Weibull model provides better characterization in the lower tail region where the predictions are of maximum design interest. The two sets of the same material were found to have essentially the same material properties, and indicate that repeatability can be achieved.

  8. Optimal control of the Lotka-Volterra system: turnpike property and numerical simulations.

    PubMed

    Ibañez, Aitziber

    2017-12-01

    The Lotka-Volterra model is a differential system of two coupled equations representing the interaction of two species: a prey one and a predator one. We formulate an optimal control problem adding the effect of hunting both species as the control variable. We analyse the optimal hunting problem paying special attention to the nature of the optimal state and control trajectories in long time intervals. To do that, we apply recent theoretical results on the frame to show that, when the time horizon is large enough, optimal strategies are nearly steady-state. Such path is known as turnpike property. Some experiments are performed to observe such turnpike phenomenon in the hunting problem. Based on the turnpike property, we implement a variant of the single shooting method to solve the previous optimisation problem, taking the middle of the time interval as starting point.

  9. HOST STAR PROPERTIES AND TRANSIT EXCLUSION FOR THE HD 38529 PLANETARY SYSTEM

    SciTech Connect

    Henry, Gregory W.; Kane, Stephen R.; Von Braun, Kaspar; Ciardi, David R.; Hinkel, Natalie R.; Wang, Sharon X.; Wright, Jason T.; Mahadevan, Suvrath; Pilyavsky, Genady; Boyajian, Tabetha S.; Fischer, Debra A.; Dragomir, Diana; Farrington, Chris; Howard, Andrew W.; Jensen, Eric; Laughlin, Gregory

    2013-05-10

    The transit signature of exoplanets provides an avenue through which characterization of exoplanetary properties may be undertaken, such as studies of mean density, structure, and atmospheric composition. The Transit Ephemeris Refinement and Monitoring Survey is a program to expand the catalog of transiting planets around bright host stars by refining the orbits of known planets discovered with the radial velocity technique. Here we present results for the HD 38529 system. We determine fundamental properties of the host star through direct interferometric measurements of the radius and through spectroscopic analysis. We provide new radial velocity measurements that are used to improve the Keplerian solution for the two known planets, and we find no evidence for a previously postulated third planet. We also present 12 years of precision robotic photometry of HD 38529 that demonstrate the inner planet does not transit and the host star exhibits cyclic variations in seasonal mean brightness with a timescale of approximately six years.

  10. A Measurement Testing Setup of the Characteristic Properties for High Temperature Superconducting bearing Systems

    NASA Astrophysics Data System (ADS)

    Lin, Qunxu; Jiang, Donghui; Wang, Jiasu; Ma, Guangtong; Yen, Fei; Deng, Zigang; Zheng, Jun; Wang, Suyu

    A measurement testing setup of the characteristic properties for high temperature superconducting bearing (HTSB) systems is introduced in this paper. The equipment setup can measure the radial and axial forces, temperature, oscillation and rotary speed of the HTSB simultaneously, so the relation between these properties can be investigated. For example, the decrease of the radial and axial forces, and the increase of the temperature can be measured and analyzed during different rotary speeds of the permanent magnetic rotor. The measurement ranges for the radial and axial force will reach 5 kN and 10 kN. The temperature of the superconductors in HTSB can then be controlled by adjusting the air press inside the dewar which is an easier method compared with a cryocooler.

  11. An airjet actuator system for identification of the human arm joint mechanical properties.

    PubMed

    Xu YMj; Hunter, I W; Hollerbach, J M; Bennett, D J

    1991-11-01

    A system is described for determining the mechanical properties of the human arm during unconstrained posture and movement. An airjet perturbation device is attached to the wrist with a special cuff, and provides high-frequency stochastic perturbations in potentially three orthogonal directions. The airjet operates as a fluidic flip-flop utilizing the Coanda effect, and generates binary force sequences with a steady-state thrust of 4 N, a flat frequency response to 75 Hz, usable thrust to 150 Hz, and a rise time of 1 ms, when the static pressure at the nozzle inlet is 5.5 x 10(5) Pa (80 psi). These operating characteristics are adequate to identify the arm's mechanical properties efficiently and robustly.

  12. Properties of a Formal Method for Prediction of Emergent Behaviors in Swarm-based Systems

    NASA Technical Reports Server (NTRS)

    Rouff, Christopher; Vanderbilt, Amy; Hinchey, Mike; Truszkowski, Walt; Rash, James

    2004-01-01

    Autonomous intelligent swarms of satellites are being proposed for NASA missions that have complex behaviors and interactions. The emergent properties of swarms make these missions powerful, but at the same time more difficult to design and assure that proper behaviors will emerge. This paper gives the results of research into formal methods techniques for verification and validation of NASA swarm-based missions. Multiple formal methods were evaluated to determine their effectiveness in modeling and assuring the behavior of swarms of spacecraft. The NASA ANTS mission was used as an example of swarm intelligence for which to apply the formal methods. This paper will give the evaluation of these formal methods and give partial specifications of the ANTS mission using four selected methods. We then give an evaluation of the methods and the needed properties of a formal method for effective specification and prediction of emergent behavior in swarm-based systems.

  13. Spectral properties of a strongly coupled quantum-dot-metal-nanoparticle system

    NASA Astrophysics Data System (ADS)

    Hakami, Jabir; Wang, Ligang; Zubairy, M. Suhail

    2014-05-01

    We investigate the coherent control of the quantum optical properties of a quantum dot coupled to a metallic nanoparticle using a photon Green's function method, which is based on the exact quantization of the electromagnetic fields in a dissipative medium. The properties of the spontaneous emission spectra of such a system are studied in detail with and without involving the coherent field. The Rabi splitting effect in the spectrum emitted by the quantum dot under particular conditions is predicted for different sizes of the metal nanoparticles. We show that the spontaneous emission spectra of the transition coupled to surface plasmons may be further modified by adjusting the external coherent control on the adjacent transitions. Furthermore, the pronounced oscillatory behavior for the quantum-dot dynamics is demonstrated with the presence of the metal nanoparticle by the non-Markovian treatment. Our results may have potential applications in plasmonic-based quantum manipulation.

  14. Lasing properties of non-resonant single quantum dot-cavity system under incoherent excitation.

    PubMed

    Guan, Huan; Yao, Peijun; Yu, Wenhai; Wang, Pei; Ming, Hai

    2012-12-17

    Single quantum dot laser has earned extensive interest due to its peculiar properties, however, most of works are focused on the resonant case. In this paper, the lasing oscillation based on off-resonant quantum dot (QD)-cavity system is investigated detailedly through two-electrons QD model. By gradually increasing the pump rate, the typical lasing signatures are shown with and without detuning, include the spectral transition from multiple peaks to single peak, and antibunching to Poissonian distribution. It is also demonstrated how detuning factor strongly influence photon statistics and emission properties, specially, the side peak of spectra induced by the exchange energy (named "sub-peak") will go across the main peak from left to right when the detuning is gradually increased, and, furthermore, we find the "sub-peak cross of spectra" will facilitate the lasing oscillation because of the existence of exchange energy.

  15. Effects of repeated baking on the mechanical and physical properties of metal-ceramic systems.

    PubMed

    Nagasawa, Sakae; Yoshida, Takamitsu; Mizoguchi, Toshihide; Terashima, Nobuyoshi; Kamijyo, Kuni; Ito, Michio; Oshida, Yoshiki

    2004-06-01

    This study evaluates effects of repeated baking processes on the mechanical and physical properties of single and triple applications of opaque, body and enamel porcelains fused to three different metal substrates (precious metal, semi-precious metal and non-precious metal). The vintage halo porcelain system was employed and fused to metals. Fused samples were subjected to three-point bend tests to evaluate bend strength and modulus of elasticity. It was found that, by increasing repeated baking cycles, (1) body and enamel porcelains increased bend strengths but opaque porcelain did not show any changes, (2) all triple-layered porcelains fired to metals increased bend strengths, and (3) all three porcelains and metal substrates did not exhibit changes in thermal expansion percentage. It was concluded that repeating baking procedures up to 10 cycles did not exhibit any adverse effects on the final properties of porcelain-fired to metals, rather it was noticed that mechanical strengths increased by increasing cycles.

  16. Bulk and surface properties of ZnTe-ZnS system semiconductors

    NASA Astrophysics Data System (ADS)

    Kirovskaya, I. A.; Mironova, E. V.; Kosarev, B. A.; Nor, P. E.; Bukashkina, T. L.

    2016-10-01

    Physicochemical studies of a new ZnTe-ZnS semiconductor system are conducted. It is found that at certain ratios of binary components, substitutional solid solutions with a cubic sphalerite structure are formed in this system. Interrelated laws governing changes in the bulk (crystal chemical, structural) and surface (acid-base) properties with varying system composition are identified. It is assumed they can be attributed to the nature of the active (acid-base) sites. The presented data, observed patterns, and an interpretation of them are used not only to confirm earlier proposed mechanisms of atomic-molecular interaction on diamond-like semiconductors, but to search for promising materials for use in highly sensitive selective sensors for environmental and medical purposes as well.

  17. Realistic Many-Body Quantum Systems vs. Full Random Matrices: Static and Dynamical Properties

    NASA Astrophysics Data System (ADS)

    Torres-Herrera, Eduardo; Karp, Jonathan; Távora, Marco; Santos, Lea

    2016-10-01

    We study the static and dynamical properties of isolated many-body quantum systems and compare them with the results for full random matrices. In doing so, we link concepts from quantum information theory with those from quantum chaos. In particular, we relate the von Neumann entanglement entropy with the Shannon information entropy and discuss their relevance for the analysis of the degree of complexity of the eigenstates, the behavior of the system at different time scales and the conditions for thermalization. A main advantage of full random matrices is that they enable the derivation of analytical expressions that agree extremely well with the numerics and provide bounds for realistic many-body quantum systems.

  18. Fano effect dominance over Coulomb blockade in transport properties of parallel coupled quantum dot system

    NASA Astrophysics Data System (ADS)

    Brogi, Bharat Bhushan; Chand, Shyam; Ahluwalia, P. K.

    2015-06-01

    Theoretical study of the Coulomb blockade effect on transport properties (Transmission Probability and I-V characteristics) for varied configuration of coupled quantum dot system has been studied by using Non Equilibrium Green Function(NEGF) formalism and Equation of Motion(EOM) method in the presence of magnetic flux. The self consistent approach and intra-dot Coulomb interaction is being taken into account. As the key parameters of the coupled quantum dot system such as dot-lead coupling, inter-dot tunneling and magnetic flux threading through the system can be tuned, the effect of asymmetry parameter and magnetic flux on this tuning is being explored in Coulomb blockade regime. The presence of the Coulomb blockade due to on-dot Coulomb interaction decreases the width of transmission peak at energy level ɛ + U and by adjusting the magnetic flux the swapping effect in the Fano peaks in asymmetric and symmetric parallel configuration sustains despite strong Coulomb blockade effect.

  19. Pathogenicity phenomena in three model systems: from network mining to emerging system-level properties.

    PubMed

    Castelhano Santos, Nadine; Pereira, Maria Olívia; Lourenço, Anália

    2015-01-01

    Understanding the interconnections of microbial pathogenicity phenomena, such as biofilm formation, quorum sensing and antimicrobial resistance, is a tremendous open challenge for biomedical research. Progress made by wet-lab researchers and bioinformaticians in understanding the underlying regulatory phenomena has been significant, with converging evidence from multiple high-throughput technologies. Notably, network reconstructions are already of considerable size and quality, tackling both intracellular regulation and signal mediation in microbial infection. Therefore, it stands to reason that in silico investigations would play a more active part in this research. Drug target identification and drug repurposing could take much advantage of the ability to simulate pathogen regulatory systems, host-pathogen interactions and pathogen cross-talking. Here, we review the bioinformatics resources and tools available for the study of the gram-negative bacterium Pseudomonas aeruginosa, the gram-positive bacterium Staphylococcus aureus and the fungal species Candida albicans. The choice of these three microorganisms fits the rationale of the review converging into pathogens of great clinical importance, which thrive in biofilm consortia and manifest growing antimicrobial resistance.

  20. The complex distribution of arterial system mechanical properties, pulsatile hemodynamics, and vascular stresses emerges from three simple adaptive rules.

    PubMed

    Nguyen, Phuc H; Coquis-Knezek, Sarah F; Mohiuddin, Mohammad W; Tuzun, Egemen; Quick, Christopher M

    2015-03-01

    Arterial mechanical properties, pulsatile hemodynamic variables, and mechanical vascular stresses vary significantly throughout the systemic arterial system. Although the fundamental principles governing pulsatile hemodynamics in elastic arteries are widely accepted, a set of rules governing stress-induced adaptation of mechanical properties can only be indirectly inferred from experimental studies. Previously reported mathematical models have assumed mechanical properties adapt to achieve an assumed target stress "set point." Simultaneous prediction of the mechanical properties, hemodynamics, and stresses, however, requires that equilibrium stresses are not assumed a priori. Therefore, the purpose of this work was to use a "balance point" approach to identify the simplest set of universal adaptation rules that simultaneously predict observed mechanical properties, hemodynamics, and stresses throughout the human systemic arterial system. First, we employed a classical systemic arterial system model with 121 arterial segments and removed all parameter values except vessel lengths and peripheral resistances. We then assumed vessel radii increase with endothelial shear stress, wall thicknesses increase with circumferential wall stress, and material stiffnesses decrease with circumferential wall stress. Parameters characterizing adaptive responses were assumed to be identical in all arterial segments. Iteratively predicting local mechanical properties, hemodynamics, and stresses reproduced five trends observed when traversing away from the aortic root towards the periphery: decrease in lumen radii, wall thicknesses, and pulsatile flows and increase in wall stiffnesses and pulsatile pressures. The extraordinary complexity of the systemic arterial system can thus arise from independent adaptation of vessels to local stresses characterized by three simple adaptive rules.

  1. Impact of thermal energy storage properties on solar dynamic space power conversion system mass

    NASA Technical Reports Server (NTRS)

    Juhasz, Albert J.; Coles-Hamilton, Carolyn E.; Lacy, Dovie E.

    1987-01-01

    A 16 parameter solar concentrator/heat receiver mass model is used in conjunction with Stirling and Brayton Power Conversion System (PCS) performance and mass computer codes to determine the effect of thermal energy storage (TES) material property changes on overall PCS mass as a function of steady state electrical power output. Included in the PCS mass model are component masses as a function of thermal power for: concentrator, heat receiver, heat exchangers (source unless integral with heat receiver, heat sink, regenerator), heat engine units with optional parallel redundancy, power conditioning and control (PC and C), PC and C radiator, main radiator, and structure. Critical TES properties are: melting temperature, heat of fusion, density of the liquid phase, and the ratio of solid-to-liquid density. Preliminary results indicate that even though overall system efficiency increases with TES melting temperature up to 1400 K for concentrator surface accuracies of 1 mrad or better, reductions in the overall system mass beyond that achievable with lithium fluoride (LiF) can be accomplished only if the heat of fusion is at least 800 kJ/kg and the liquid density is comparable to that of LiF (1800 kg/cu m).

  2. Impact of thermal energy storage properties on solar dynamic space power conversion system mass

    NASA Technical Reports Server (NTRS)

    Juhasz, Albert J.; Coles-Hamilton, Carolyn E.; Lacy, Dovie E.

    1987-01-01

    A 16 parameter solar concentrator/heat receiver mass model is used in conjunction with Stirling and Brayton Power Conversion System (PCS) performance and mass computer codes to determine the effect of thermal energy storage (TES) material property changes on overall PCS mass as a function of steady state electrical power output. Included in the PCS mass model are component masses as a function of thermal power for: concentrator, heat receiver, heat exchangers (source unless integral with heat receiver, heat sink, regenerator), heat engine units with optional parallel redundancy, power conditioning and control (PC and C), PC and C radiator, main radiator, and structure. Critical TES properties are: melting temperature, heat of fusion, density of the liquid phase, and the ratio of solid-to-liquid density. Preliminary results indicate that even though overalll system efficiency increases with TES melting temperature up to 1400 K for concentrator surface accuracies of 1 mrad or better, reductions in the overall system mass beyond that achievable with lithium fluoride (LiF) can be accomplished only if the heat of fusion is at least 800 kJ/kg and the liquid density is comparable to that of LiF (1880 kg/cu m.

  3. Using SEVIRI radiances to retrieve cloud optical properties of convective cloud systems

    NASA Astrophysics Data System (ADS)

    Müller, Jennifer; Fischer, Jürgen; Hünerbein, Anja; Deneke, Hartwig; Macke, Andreas

    2013-05-01

    In this case study the development of cloud properties (cloud optical depth, effective radius and cloud top height) during the life-cycle of a convective cloud system over Europe was analyzed. To retrieve the properties we developed a retrieval scheme based on the radiative transfer code MOMO and an optimal estimation procedure. Input data are the visible to short-wavelength infrared channels from SEVIRI. In contrast to many other retrieval schemes we used 4 channels simultaneously. Especially the 3,9μm channel provides additional information due to the fact that it measures solar reflectance and thermal emission and allows the inclusion of cloud top height into the retrieval. By using a time series of SEVIRI measurements we want to provide and examine the microphysical development of the cloud over life-time. We monitored the growth of the system and found the most active parts of the convection with the highest water content and optical depth in those regions where the cloud top height is largest, too. The effective radius of the cloud particles is largest in older regions of the cloud system, where the cloud is already decaying.

  4. Geometric Properties of a Mechanical Forward Motion Compensation System Controlled by a Piezoelectric Drive

    NASA Astrophysics Data System (ADS)

    Collette, F.; Gline, S.; Losseau, J.; Lecharlier, L.

    2012-07-01

    Forward Motion Compensation (FMC) systems have been designed to ensure the radiometric quality of motion acquisition in airborne cameras. If the radiometric benefits of FMC have been acknowledged, what are its effects on the geometrical properties of the camera? This paper demonstrates that FMC significantly improves geometrical properties of a camera. Aspects of FMC theory are discussed, with a focus on the near-lossless implementation of this technology into digital aerial camera systems. Among mechanical FMC technologies, the piezoelectric drive is proving to excel in dynamic positioning in both accuracy and repeatability. The patented piezoelectric drive integrated into Optech aerial camera systems allows for continuous and precise sensor motion to ensure exact compensation of the aircraft's forward motion. This paper presents findings that demonstrate the validity of this assertion. The paper also discusses the physical principles involved in motion acquisition. Equations are included that define the motion effect at image level and illustrate how FMC acts to prevent motion effects. The residual motion effect or compensation error is formulated and a practical computation applied to the more restrictive camera case. The assessment concludes that, in the range of airborne camera utilization, the mechanical FMC technique is free of "visible" error at both human eye and computer assessment level. Lastly, the paper proceeds to a detailed technical discussion of piezoelectric drives and why they have proven to be so effective as nanopositioning devices for optical applications. The effectiveness of the patented piezoelectric drives used to achieve FMC in Optech cameras is conclusively demonstrated.

  5. Influence of Photoinitiator System on Physical-Chemical Properties of Experimental Self-Adhesive Composites.

    PubMed

    Bertolo, Marcus Vinicius Loureiro; Moraes, Rita de Cássia Martins; Pfeifer, Carmem; Salgado, Vinícius Esteves; Correr, Ana Rosa Costa; Schneider, Luis Felipe J

    2017-01-01

    The aim of this study was to determine the influence of photoinitiator systems on physical-chemical properties of flowable composites. Conventional (CFC), composed by bisphenol-glycidyl dimethacrylate (BisGMA)+triethyleneglycol dimethacrylate (TEGDMA), and self-adhesive (SAFC), composed by BisGMA+TEDGMA+bis{2-(methacryloyloxy) ethyl} phosphate (2MP), flowable composites were developed. Five photoinitiator systems were tested: camphorquinone (CQ), ethyl-4-dimethylaminobenzoate (EDMAB), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), phenylbis (2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), CQ+EDMAB+TPO and CQ+EDMAB+BAPO. A two-peak LED was used; degree of conversion (DC) and the maximum polymerization rate (RPmax) were determined by near infrared spectroscopy. For the yellowing degree a spectrophotometer was used. Water sorption (Wsp) was obtained after 30 days of water storage (n=5). Data were submitted to two-way analysis of variance and Tukey's test (a=0.05). BAPO presented the highest DC and RPmax values for both series. SAFCs presented lower DC and RPmax for CQ+EDMAB-based materials. Greater yellowing was observed for SAFCs compared with CFCs, except for BAPO. Greater Wsp was observed for SAFCs compared with CFCs. The photoinitiator did not influence Wsp for CFCs, but TPO and BAPO presented the highest Wsp in SAFCs. The photoinitiator system affected differently the physical-chemical properties of CFCs and SAFCs.

  6. Factors that influence properties of FOG deposits and their formation in sewer collection systems.

    PubMed

    Iasmin, Mahbuba; Dean, Lisa O; Lappi, Simon E; Ducoste, Joel J

    2014-02-01

    Understanding the formation of Fat, Oil, and Grease (FOG) deposits in sewer systems is critical to the sustainability of sewer collection systems since they have been implicated in causing sewerage blockages that leads to sanitary sewer overflows (SSOs). Recently, FOG deposits in sewer systems displayed strong similarities with calcium-based fatty acid salts as a result of a saponification reaction. The objective of this study was to quantify the factors that may affect the formation of FOG deposits and their chemical and rheological properties. These factors included the types of fats used in FSEs, environmental conditions (i.e. pH and temperature), and the source of calcium in sewer systems. The results of this study showed that calcium content in the calcium based salts seemed to depend on the solubility limit of the calcium source and influenced by pH and temperature conditions. The fatty acid profile of the calcium-based fatty acid salts produced under alkali driven hydrolysis were identical to the profile of the fat source and did not match the profile of field FOG deposits, which displayed a high fraction of palmitic, a long chain saturated fatty acid. It is hypothesized that selective microbial metabolism of fats and/or biologically induced hydrogenation may contribute to the FOG deposit makeup in sewer system. Therefore, selective removal of palmitic in pretreatment processes may be necessary prior to the discharge of FSE wastes into the sewer collection system.

  7. Research of aberration properties and passive athermalization of optical systems for infrared region

    NASA Astrophysics Data System (ADS)

    Romanova, Galina E.; Pyś, Grzegorz

    2015-09-01

    Infrared optical systems are widely used for surveillance, military and many other purposes. Image quality of such systems should be stable over wide working temperature range from - 40 up to +60°C. Due to temperature dependence of properties of optical materials and mechanical parts it is a difficult task to achieve the required stability. Passive and active methods exist to compensate the most significant aberration - so called thermal defocus. Passive compensation ways are the most attractive because complicated mechanical parts or devices are not required. The work is aimed at developing and improving of the IR system design methods. The analysis of thermoaberrations starts with analysis of possibilities of chromatic and thermal defocus correction in two and three component systems. Based on these results the development and improvement of the design method which was proposed earlier was implemented. Examples of designed systems are given. Results of the work may be helpful for designers to find optimal material combination for further designing of thermostabilized systems working in IR region.

  8. Analysis of nodal aberration properties in off-axis freeform system design.

    PubMed

    Shi, Haodong; Jiang, Huilin; Zhang, Xin; Wang, Chao; Liu, Tao

    2016-08-20

    Freeform surfaces have the advantage of balancing off-axis aberration. In this paper, based on the framework of nodal aberration theory (NAT) applied to the coaxial system, the third-order astigmatism and coma wave aberration expressions of an off-axis system with Zernike polynomial surfaces are derived. The relationship between the off-axis and surface shape acting on the nodal distributions is revealed. The nodal aberration properties of the off-axis freeform system are analyzed and validated by using full-field displays (FFDs). It has been demonstrated that adding Zernike terms, up to nine, to the off-axis system modifies the nodal locations, but the field dependence of the third-order aberration does not change. On this basis, an off-axis two-mirror freeform system with 500 mm effective focal length (EFL) and 300 mm entrance pupil diameter (EPD) working in long-wave infrared is designed. The field constant aberrations induced by surface tilting are corrected by selecting specific Zernike terms. The design results show that the nodes of third-order astigmatism and coma move back into the field of view (FOV). The modulation transfer function (MTF) curves are above 0.4 at 20 line pairs per millimeter (lp/mm) which meets the infrared reconnaissance requirement. This work provides essential insight and guidance for aberration correction in off-axis freeform system design.

  9. Assessment of the Sensitivity of Distributions of Climate System Properties to Methodology and Model Diagnostics

    NASA Astrophysics Data System (ADS)

    Libardoni, A. G.; Forest, C. E.

    2012-12-01

    This study explores the sensitivity of probability distribution functions for climate sensitivity, the rate of ocean heat uptake, and the net anthropogenic aerosol forcing to multiple factors. First, the impact on the distributions of the method used when using surface temperatures to evaluate model performance is explored. Specifically, the treatment of missing data in the surface observations and how it is used to mask the model data is modified and its impact evaluated. Second, the sensitivity of the distributions to the reference climatology used to calculate surface temperature anomalies is explored. Third, the sensitivity of the distributions to the observational data sources is explored. In total, five different surface temperature datasets and three different ocean heat content datasets are used. Lastly, the impact of including more recent data in the surface and ocean heat content records is explored. Contained in this exploration is an evaluation of how using a longer surface temperature record (six decades versus five decades) in model evaluation impacts the resulting distributions. The probability distributions are derived using a two-step process consisting of: 1) running a single climate model while varying the parameter settings for each model run and 2) evaluating the performance of a given model through the comparison of model output to observed climate records. The MIT Integrated Assessment Model is used due to its efficiency and ability to easily modify the three climate system properties that are assessed. Model output for a given set of parameters is compared to historical surface temperature, ocean heat content, and upper-air temperature patterns and the resulting goodness-of-fit statistics are used to derive probability distributions for the system properties. Understanding the uncertainties that are attributable to each of the factors described above allows for a more thorough analysis of climate system properties and will help guide the

  10. Evolution and Mean Properties of Convective Systems in Southwestern Amazonia During TRMM-LBA

    NASA Technical Reports Server (NTRS)

    Rickenbach, Thomas M.; Ferreira, Rosana Nieto; Halverson, Jeffrey B.; deSilvaDias, Maria A. F.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    During the wet season TRMM field campaign in Rondonia, Brazil, a variety of convective systems were sampled by radar, sounding, and geostationary satellite for a 60 day period in early 1999. Local variations in the local wind and humidity field have been attributed in part by this study to synoptic scale phenomena, most conspicuously the establishment of stationary frontal systems penetrating into the tropics. These baroclinic systems induced periodic episodes low level moist, westerly flow across Rondonia during the experiment. This flow feature may be an important component of the South American climate system by playing a role in maintaining the South Atlantic Convergence Zone, which was active during these local westerly wind events. It is therefore important to understand the differences in mesoscale properties of convective systems between the westerly wind periods and intervening easterly wind periods. Differences in shear and moisture characteristics (Halverson et al. 2000, this meeting) are compared to structural and life-cycle characteristics of convective systems in Rondonia. Data from ground based radar and geostationary satellite provide a view of the evolution of the vertical structure and horizontal morphology of several large mesoscale convective systems in each regime. Preliminary statistics on the diurnal variation of precipitation intensity, areal coverage, and cloud top area are presented. Results suggest that long-lived, shallow convective systems with a large stratiform component of precipitation are characteristic of the westerly wind periods. A goal of this study is to establish a basis for which to parameterize the mesoscale effects of convection on large scale features of the South American climate system.

  11. Modeling and Properties of Nonlinear Stochastic Dynamical System of Continuous Culture

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Feng, Enmin; Ye, Jianxiong; Xiu, Zhilong

    The stochastic counterpart to the deterministic description of continuous fermentation with ordinary differential equation is investigated in the process of glycerol bio-dissimilation to 1,3-propanediol by Klebsiella pneumoniae. We briefly discuss the continuous fermentation process driven by three-dimensional Brownian motion and Lipschitz coefficients, which is suitable for the factual fermentation. Subsequently, we study the existence and uniqueness of solutions for the stochastic system as well as the boundedness of the Two-order Moment and the Markov property of the solution. Finally stochastic simulation is carried out under the Stochastic Euler-Maruyama method.

  12. Study of the Properties of Plessey's Electrocardiographic Capacitive Electrodes for Portable Systems

    NASA Astrophysics Data System (ADS)

    Uvarov, A. A.; Lezhnina, I. A.; Overchuk, K. V.; Starchak, A. S.; Akhmedov, Sh D.; Larioshina, I. A.

    2016-01-01

    Cardiac diseases are still most widely spread in all regions of the world. And more and more devices are invented to satisfy increasing requirements of the patients. One of the perspective technologies in cardiac diagnostics is capacitive sensing ECG electrodes. This article describes a study of the properties of electrocardiographic capacitive electrodes PS25255 from Plessey Semiconductors for portable systems as well as some undocumented parameters of these sensors. We developed special cardiograph using Plessey's electrodes and applied to the number of patients with ischemic heart disease. We paid our attention mostly to the correct transition of the ST segment as it has critical impact on the diagnostics of ischemic heart disease.

  13. Optical Properties of a Quantum Dot-Ring System Grown Using Droplet Epitaxy.

    PubMed

    Linares-García, Gabriel; Meza-Montes, Lilia; Stinaff, Eric; Alsolamy, S M; Ware, M E; Mazur, Y I; Wang, Z M; Lee, Jihoon; Salamo, G J

    2016-12-01

    Electronic and optical properties of InAs/GaAs nanostructures grown by the droplet epitaxy method are studied. Carrier states were determined by k · p theory including effects of strain and In gradient concentration for a model geometry. Wavefunctions are highly localized in the dots. Coulomb and exchange interactions are studied and we found the system is in the strong confinement regime. Microphotoluminescence spectra and lifetimes were calculated and compared with measurements performed on a set of quantum rings in a single sample. Some features of spectra are in good agreement.

  14. Analysis of corrugated cardboard influence on the protective properties of complex packaging system

    NASA Astrophysics Data System (ADS)

    Osowski, Przemyslaw; Piatkowski, Tomasz

    2017-03-01

    According to available literature, it is assumed that outer packaging container, which is usually made of corrugated cardboard, does not influence the mitigation of the impact effects, thus in the designing process of packaging system the outer packaging is skipped. The purpose of this paper is to verify the above assumption, including determination of the influence of the 5-layer cardboard on the properties of structures that consist of that cardboard and polyethylene foam. Verification is performed with the use of the finite element method. To apply this method the dynamic compression curve of cushioning material is required. Therefore in the paper it is also presented the modified method to determine the curve.

  15. Nonlinear electric properties in biological system for stochastic computing (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Sumida, Saki; Yamaguchi, Harumasa; Ohyama, Hiroshi; Otsuka, Yoichi; Che, Dock-Chil; Matsumoto, Takuya

    2016-09-01

    Nonlinearity is the vital factor for stochastic computing. Toward the realization of brain-mimetic function using molecular network, the nonlinear electric properties of molecular systems are investigated in nanoscale with atomic force microscopy and nano-gap electrodes. Nonlinear current-voltage characteristics were observed for {Mo154/152}-ring, cytochorome c, and cytochrome c/DNA networks where the conduction paths include electron injection into weakly coupled discrete energy levels, electron tunneling through potential well, and electron hopping via Coulomb-blockade network. Stochastic resonance was observed in Cytochrome c/DNA network.

  16. Eigen-Property of Single-j System and Seniority Conservation Condition

    NASA Astrophysics Data System (ADS)

    Wang, Xiaobao; Qi, Chong; Xu, Furong

    2012-05-01

    In this paper we study the system with three nucleons within a single-j shell, which can be described as the angular momentum coupling of a nucleon pair and the odd nucleon. The overlaps between these non-orthonormal states form a special matrix coincidental with the one obtained by Rowe and Rosensteel. They proposed a proposition related to the eigenvalue problems of that matrix and dimensions of the associated subspaces. We prove their proposition with the help of the symmetric properties of the six-j symbols. We also derive algebraic expressions for eigen energies as well as conditions for conservation of seniority through the decomposition of the angular momentum.

  17. Control of a wheeled system taking into account its inertial properties

    NASA Astrophysics Data System (ADS)

    Matyukhin, V. I.

    2013-05-01

    Mechanical wheeled systems (WS) such as a wheeled tractor, a motor car, a mobile robot, etc. are studied. The well-known trajectory problem, i.e., the problem of controlling the WS motion along a given trajectory, is considered. This problem was solved earlier in the framework of kinematic WS models. The present paper deals with general WS models that additionally take into account inertial properties such as the WS masses and/or moments of inertia. We establish that the WS are subjected to rather significant perturbing forces. A control law stabilizing the WS motion along a given trajectory is constructed.

  18. Motion properties of the sanals of the primo vascular system under a magnetic field.

    PubMed

    Lee, Sang Suk

    2013-12-01

    The motion properties of the sanals of the primo vascular system were investigated under a low static magnetic field of 100 Oe. Sanals of about 1 μm were selected and separated from the primo vessels and nodes on a rabbit's organ surface. The average velocity of five sanals in a physiologic saline solution parallel and perpendicular to the direction of the applied magnetic field was approximately 1.0 pixel/second in random directions, which implies that the rotating motion of sanals with nuclei composed of DNA containing many inorganic magnetic elements such as manganese and cobalt is monotonically weakened by increasing an applied magnetic field.

  19. An experimental test plan for the characterization of molten salt thermochemical properties in heat transport systems

    SciTech Connect

    Pattrick Calderoni

    2010-09-01

    Molten salts are considered within the Very High Temperature Reactor program as heat transfer media because of their intrinsically favorable thermo-physical properties at temperatures starting from 300 C and extending up to 1200 C. In this context two main applications of molten salt are considered, both involving fluoride-based materials: as primary coolants for a heterogeneous fuel reactor core and as secondary heat transport medium to a helium power cycle for electricity generation or other processing plants, such as hydrogen production. The reference design concept here considered is the Advanced High Temperature Reactor (AHTR), which is a large passively safe reactor that uses solid graphite-matrix coated-particle fuel (similar to that used in gas-cooled reactors) and a molten salt primary and secondary coolant with peak temperatures between 700 and 1000 C, depending upon the application. However, the considerations included in this report apply to any high temperature system employing fluoride salts as heat transfer fluid, including intermediate heat exchangers for gas-cooled reactor concepts and homogenous molten salt concepts, and extending also to fast reactors, accelerator-driven systems and fusion energy systems. The purpose of this report is to identify the technical issues related to the thermo-physical and thermo-chemical properties of the molten salts that would require experimental characterization in order to proceed with a credible design of heat transfer systems and their subsequent safety evaluation and licensing. In particular, the report outlines an experimental R&D test plan that would have to be incorporated as part of the design and operation of an engineering scaled facility aimed at validating molten salt heat transfer components, such as Intermediate Heat Exchangers. This report builds on a previous review of thermo-physical properties and thermo-chemical characteristics of candidate molten salt coolants that was generated as part of the

  20. Physical Properties of Lyman-alpha Forest and Damped Lyman-alpha Systems

    NASA Astrophysics Data System (ADS)

    Kulkarni, V. P.; Fall, S. M.

    1995-12-01

    We present a review of our results regarding various physical properties of quasar absorption line systems, in particular, the Lyman-alpha forest and the damped Lyman-alpha systems. We made the first detection of the quasar proximity effect at low redshifts, using HST Key Project data on the Ly-alpha forest for z < 1. This allowed the first empirical estimate of the intensity of the ionizing UV background at < z > ~ 0.5 and showed evidence for evolution of the ionizing UV background with redshift. We have also studied the implications of non-thermal motions inside Ly-alpha forest clouds for the statistics of these clouds. We showed that the distributions in H I column densities f(N) for systems with saturated Ly-alpha lines and the extent (and sign) of N-sigma correlations could differ from previous estimates, if the clouds possessed non-Maxwellian velocity distributions. We also present results of a study of the chemical properties of several damped Lyman-alpha systems, based on published high-sensitivity observations. In particular, we examine the total (gas + solid phase) metallicity and the dust content of these systems. Results will also be presented of an analysis of an 18 km s(-1) resolution spectrum of the Ly-alpha forest of the z = 2.1 quasar Q1331+170, performed in collaboration with Dr. D. G. York, Dr. D. E. Welty (U. Chicago), Dr. R. F. Green, Dr. K. Huang (NOAO) and Dr. J. Bechtold (U. Arizona). One of the main results is some evidence for small-scale clustering among the Ly-alpha forest clouds.

  1. Measurement of the biophysical properties of porcine adipose-derived stem cells by a microperfusion system.

    PubMed

    Wang, Jianye; Zhao, Gang; Zhang, Pengfei; Wang, Zhen; Zhang, Yunhai; Gao, Dayong; Zhou, Ping; Cao, Yunxia

    2014-12-01

    Adipose-derived stem cells (ADSCs), which are an accessible source of adult stem cells with capacities for self-renewal and differentiation into various cell types, have a promising potential in tissue engineering and regenerative medicine strategies. To meet the clinical demand for ADSCs, cryopreservation has been applied for long-term ADSC preservation. To optimize the addition, removal, freezing, and thawing of cryoprotective agents (CPAs) applied to ADSCs, we measured the transport properties of porcine ADSCs (pADSCs). The cell responses of pADSCs to hypertonic phosphate-buffered saline and common CPAs, dimethyl sulfoxide, ethylene glycol, and glycerol were measured by a microperfusion system at temperatures of 28, 18, 8, and -2°C. We determined the osmotically inactive cell volume (Vb), hydraulic conductivity (Lp), and CPA permeability (Ps) at various temperatures in a two-parameter model. Then, we quantitatively analyzed the effect of temperature on the transport properties of the pADSC membrane. Biophysical parameters were used to optimize CPA addition, removal, and freezing processes to minimize excessive shrinkage of pADSCs during cryopreservation. The biophysical properties of pADSCs have a great potential for effective optimization of cryopreservation procedures.

  2. Advances in star-shaped π-conjugated systems: properties and applications.

    PubMed

    Jarosz, Tomasz; Lapkowski, Mieczyslaw; Ledwon, Przemyslaw

    2014-06-01

    Until recently π-conjugated organic materials are based mainly on linear systems. Recent years, however, have brought about increasing interest in molecules boasting a dendritic, branched, or star-shaped architecture. This tendency is a direct result of the ongoing search for materials with progressively better properties. Such compounds, featuring novel, 3D architectures, exhibit a multitude of interesting qualities, making them stand out from well-known materials. The direction of star-shaped compound application is determined by whether they are able to form aggregates, π-stacks. This feature is a source of some astounding properties, coveted in numerous applications. Among this class of compounds high charge mobility, high fluorescence efficiency, and good charge separation are all found. Depending on the structure of the core, the molecule may adopt various types of symmetry. Similarly, the conjugation of orbitals may extend over the whole structure or be interrupted at chosen segments. The number of papers pertaining to star-shaped oligomers and polymers is ascending with each year, evidencing a growing interest in them. Consequently, this Review focuses particularly on the most recent reports concerning modification of the structure and properties of the aforementioned type of compounds, as well as on the development of devices based on them.

  3. Constraining the Evolution of Galaxy Properties in Interacting Systems with UV-FIR Observations and Simulations

    NASA Astrophysics Data System (ADS)

    Lanz, Lauranne; Zezas, A.; Brassington, N.; Smith, H. A.; Ashby, M. N.; da Cunha, E.; Hayward, C. C.; Jonsson, P.; Hernquist, L. E.; Fazio, G. G.

    2013-01-01

    The evolution of galaxies is greatly influenced by their interactions. As part of the Spitzer Interacting Galaxy Survey (SIGS), we imaged 48 nearby systems with Spitzer. We measured and modeled the spectral energy distributions (SEDs) at wavelengths from the ultraviolet (UV) to the far-infrared (FIR) of the set of these galaxies with publicly available Herschel SPIRE observations. We fit these SEDs with the Bayesian SED-fitting program MAGPHYS developed by da Cunha et al. (2008). In order to determine the reliability of the parameters extracted, we determined how well MAGPHYS recovers parameters of hydrodynamic simulations run with GADGET (Springel et al. 2005) and for which simulated photometry was calculated using the SUNRISE radiative transfer code (Jonsson et al. 2010). We present our conclusions on the variations with interaction stage of galaxy properties including: star formation histories; dust luminosities, temperatures, and masses; and stellar masses. We discuss how successfully MAGPHYS recovers galaxy properties and which instruments are most crucial for constraining masses, star formation histories, and dust properties. We compare the simulations directly to the observations, examining how unique a diagnostic an interacting galaxy SED can be. Finally, we compare and discuss how well the many simple star formation estimating relations (using 24 micron flux, for example) succeed and why.

  4. Development of an active food packaging system with antioxidant properties based on green tea extract.

    PubMed

    Carrizo, Daniel; Gullo, Giuseppe; Bosetti, Osvaldo; Nerín, Cristina

    2014-01-01

    A formula including green tea extract (GTE) was developed as an active food packaging material. This formula was moulded to obtain an independent component/device with antioxidant properties that could be easily coupled to industrial degassing valves for food packaging in special cases. GTE components (i.e., gallic acid, catechins and caffeine) were identified and quantified by HPLC-UV and UPLC-MS and migration/diffusion studies were carried out. Antioxidant properties of the formula alone and formula-valve were measured with static and dynamic methods. The results showed that the antioxidant capacity (scavenging of free radicals) of the new GTE formula was 40% higher than the non-active system (blank). This antioxidant activity increased in parallel with the GTE concentration. The functional properties of the industrial target valve (e.g., flexibility) were studied for different mixtures of GTE, and good results were found with 17% (w/w) of GTE. This new active formula can be an important addition for active packaging applications in the food packaging industry, with oxidative species-scavenging capacity, thus improving the safety and quality for the consumer and extending the shelf-life of the packaged food.

  5. ESTIMATION OF INHERENT OPTICAL PROPERTIES AND THE WATER QUALITY COMPONENTS IN THE NEUSE RIVER-PAMLICO SOUND ESTUARINE SYSTEM

    EPA Science Inventory

    Field observations carried out in the Neuse River-Pamlico Sound Estuarine System (NRE-PS), North Carolina, USA were used to develop optical algorithms for assessing inherent optical properties, IOPs (absorption and backscattering) associated with water quality components (WQC).

  6. Retrievals of Ice Cloud Microphysical Properties of Deep Convective Systems using Radar Measurements

    NASA Astrophysics Data System (ADS)

    Tian, J.; Dong, X.; Xi, B.; Wang, J.; Homeyer, C. R.

    2015-12-01

    This study presents innovative algorithms for retrieving ice cloud microphysical properties of Deep Convective Systems (DCSs) using Next-Generation Radar (NEXRAD) reflectivity and newly derived empirical relationships from aircraft in situ measurements in Wang et al. (2015) during the Midlatitude Continental Convective Clouds Experiment (MC3E). With composite gridded NEXRAD radar reflectivity, four-dimensional (space-time) ice cloud microphysical properties of DCSs are retrieved, which is not possible from either in situ sampling at a single altitude or from vertical pointing radar measurements. For this study, aircraft in situ measurements provide the best-estimated ice cloud microphysical properties for validating the radar retrievals. Two statistical comparisons between retrieved and aircraft in situ measured ice microphysical properties are conducted from six selected cases during MC3E. For the temporal-averaged method, the averaged ice water content (IWC) and median mass diameter (Dm) from aircraft in situ measurements are 0.50 g m-3 and 1.51 mm, while the retrievals from radar reflectivity have negative biases of 0.12 g m-3 (24%) and 0.02 mm (1.3%) with correlations of 0.71 and 0.48, respectively. For the spatial-averaged method, the IWC retrievals are closer to the aircraft results (0.51 vs. 0.47 g m-3) with a positive bias of 8.5%, whereas the Dm retrievals are larger than the aircraft results (1.65 mm vs. 1.51 mm) with a positive bias of 9.3%. The retrieved IWCs decrease from ~0.6 g m-3 at 5 km to ~0.15 g m-3 at 13 km, and Dm values decrease from ~2 mm to ~0.7 mm at the same levels. In general, the aircraft in situ measured IWC and Dm values at each level are within one standard derivation of retrieved properties. Good agreements between microphysical properties measured from aircraft and retrieved from radar reflectivity measurements indicate the reasonable accuracy of our retrievals.

  7. Transport, geometrical, and topological properties of stealthy disordered hyperuniform two-phase systems.

    PubMed

    Zhang, G; Stillinger, F H; Torquato, S

    2016-12-28

    Disordered hyperuniform many-particle systems have attracted considerable recent attention, since they behave like crystals in the manner in which they suppress large-scale density fluctuations, and yet also resemble statistically isotropic liquids and glasses with no Bragg peaks. One important class of such systems is the classical ground states of "stealthy potentials." The degree of order of such ground states depends on a tuning parameter χ. Previous studies have shown that these ground-state point configurations can be counterintuitively disordered, infinitely degenerate, and endowed with novel physical properties (e.g., negative thermal expansion behavior). In this paper, we focus on the disordered regime (0 < χ < 1/2) in which there is no long-range order and control the degree of short-range order. We map these stealthy disordered hyperuniform point configurations to two-phase media by circumscribing each point with a possibly overlapping sphere of a common radius a: the "particle" and "void" phases are taken to be the space interior and exterior to the spheres, respectively. The hyperuniformity of such two-phase media depends on the sphere sizes: While it was previously analytically proven that the resulting two-phase media maintain hyperuniformity if spheres do not overlap, here we show numerically that they lose hyperuniformity whenever the spheres overlap. We study certain transport properties of these systems, including the effective diffusion coefficient of point particles diffusing in the void phase as well as static and time-dependent characteristics associated with diffusion-controlled reactions. Besides these effective transport properties, we also investigate several related structural properties, including pore-size functions, quantizer error, an order metric, and percolation thresholds. We show that these transport, geometrical, and topological properties of our two-phase media derived from decorated stealthy ground states are distinctly

  8. Differential flatness properties and multivariable adaptive control of ovarian system dynamics

    NASA Astrophysics Data System (ADS)

    Rigatos, Gerasimos

    2016-12-01

    The ovarian system exhibits nonlinear dynamics which is modeled by a set of coupled nonlinear differential equations. The paper proposes adaptive fuzzy control based on differential flatness theory for the complex dynamics of the ovarian system. It is proven that the dynamic model of the ovarian system, having as state variables the LH and the FSH hormones and their derivatives, is a differentially flat one. This means that all its state variables and its control inputs can be described as differential functions of the flat output. By exploiting differential flatness properties the system's dynamic model is written in the multivariable linear canonical (Brunovsky) form, for which the design of a state feedback controller becomes possible. After this transformation, the new control inputs of the system contain unknown nonlinear parts, which are identified with the use of neurofuzzy approximators. The learning procedure for these estimators is determined by the requirement the first derivative of the closed-loop's Lyapunov function to be a negative one. Moreover, Lyapunov stability analysis shows that H-infinity tracking performance is succeeded for the feedback control loop and this assures improved robustness to the aforementioned model uncertainty as well as to external perturbations. The efficiency of the proposed adaptive fuzzy control scheme is confirmed through simulation experiments.

  9. Electrical properties of frog skeletal muscle fibers interpreted with a mesh model of the tubular system.

    PubMed Central

    Mathias, R T; Eisenberg, R S; Valdiosera, R

    1977-01-01

    This paper presents the construction, derivation, and test of a mesh model for the electrical properties of the transverse tubular system (T-system) in skeletal muscle. We model the irregular system of tubules as a random network of miniature transmission lines, using differential equations to describe the potential between the nodes and difference equations to describe the potential at the nodes. The solution to the equations can be accurately represented in several approximate forms with simple physical and graphical interpretations. All the parameters of the solution are specified by impedance and morphometric measurements. The effect of wide circumferential spacing between T-system openings is analyzed and the resulting restricted mesh model is shown to be approximated by a mesh with an access resistance. The continuous limit of the mesh model is shown to have the same form as the disk model of the T-system, but with a different expression for the tortuosity factor. The physical meaning of the tortuosity factor is examined, and a short derivation of the disk model is presented that gives results identical to the continuous limit of the mesh model. Both the mesh and restricted mesh models are compared with experimental data on the impedance of muscle fibers of the frog sartorius. The derived value for the resistivity of the lumen of the tubules is not too different from that of the bathing solution, the difference probably arising from the sensitivity of this value to errors in the morphometric measurements. Images FIGURE 4 PMID:831857

  10. Adapting the design of Anesthesia Information Management Systems to innovations depicted in Industrial Property documents.

    PubMed

    Spyropoulos, B; Tzavaras, A; Zogogianni, D; Botsivaly, M

    2013-01-01

    The purpose of this paper is to present the design and the current development status of an Anesthesia Information Management System (AIMS). For this system, the physical and technical advances, depicted in relevant, recently published Industrial Property documents, have been taken into account. Additional innovative sensors create further data-load to be managed. Novel wireless data-transmission modes demand eventually compliance to further proper standards, so that interoperability between AIMS and the existing Hospital Information Systems is being sustained. We attempted to define, the state-of-the-art concerning the functions, the design-prerequisites and the relevant standards and of an "emerging" AIMS that is combining hardware innovation, real-time data acquisition, processing and displaying and lastly enabling the necessary interoperability with the other components of the existing Hospital Information Systems. Finally, we report based on this approach, about the design and implementation status, of our "real-world" system under development and discuss the multifarious obstacles encountered during this still on-going project.

  11. Theoretical models of the spectrophotometric properties of atmosphereless bodies surfaces in the Solar System

    NASA Astrophysics Data System (ADS)

    Ciarniello, Mauro

    2012-01-01

    In space missions remote sensing represents one of the most powerful tools for the observations of planetary objects. It allows to infer physical and chemical properties both of surfaces and atmospheres by spectroscopic and photometric analysis. However data produced by remote sensing observations need to be interpreted by physical models which describe the interaction between light and observed media. In this work we have applied the Hapke's solution to the radiative transfer equation to data from the VIMS spectrometer onboard the Cassini spacecraft, orbiting in the Saturn's system. This allowed us to determine the spectrophotometric properties of the major icy moons. In particular the composition of Mimas, Tethys, Dione, Rhea and Enceladus has been investigated. For the two latter moons also photometric properties have been studied. It comes out that the surfaces of these satellites can be modeled with water ice particles (40-70 μm in size) e minimal amounts (generally < 1%) of organic contaminants, like tholins and amorphous carbon. A similar approach has been applied to the study of the Saturn's rings (A, B, C and Cassini Division), whose spectral characteristics can be obtained with the same paradigm of composition. At the same time we have applied the Hapke's model to laboratory spectra of pyroxenes powders with well-known composition and physical properties. The aim of this study is to investigate the spectral and photometric output of these minerals to be compared with data from space missions. Moreover it was investigated how geometric and compositional effects can modify spectral signatures (for example the band depth). A further step of this investigation was the application of the Hapke's model to retrieve medium optical constants. The last part of this thesis concerns the development of an IDL routine to simulate light scattering in particulate media with a Montecarlo method. Preliminary results are reported.

  12. First-Principles Study for Thermodynamic Properties of Solid {KNO}2 System

    NASA Astrophysics Data System (ADS)

    Peng, Qiang; Ding, Jing; Wei, Xiaolan; Jiang, Gan; Yang, Xiaoxi

    2015-11-01

    To enable us better understand the performance of molten salt energy storage in a solar thermal power system, thermodynamic properties of the solid {KNO}2 system at ambient pressure and temperatures between 0 K and 711 K are determined by first-principles simulation based on density functional perturbation theory calculations with plane waves and pseudopotentials. Thermodynamic parameters of the Debye temperature, specific heat capacity at constant volume, phonon transfer speed, phonon mean free path, and phonon thermal conductivity as a function of temperature are estimated. The results show that the calculated phonon thermal conductivity is in good agreement with experimental values, but the calculated specific heat capacity at constant volume is lower than measured values. The isometric specific heat capacity of {KNO}2 is 75.03 {J}{\\cdot }{mol}^{-1}{\\cdot }{K}^{-1}, and the phonon thermal conductivity is 2.37 {W}{\\cdot }{m}^{-1}{\\cdot }{K}^{-1} at ambient temperature.

  13. Impact of strain on the electronic properties of InAs/GaSb quantum well systems

    NASA Astrophysics Data System (ADS)

    Tiemann, L.; Mueller, S.; Wu, Q.-S.; Tschirky, T.; Ensslin, K.; Wegscheider, W.; Troyer, M.; Soluyanov, A. A.; Ihn, T.

    2017-03-01

    Electron-hole hybridization in InAs/GaSb double quantum well structures leads to the formation of a mini-band-gap. We experimentally and theoretically studied the impact of strain on the transport properties of this material system. Thinned samples were mounted to piezoelectric elements to exert strain along the [011] and [001] crystal directions. When the Fermi energy is tuned through the minigap, the resistivity at the charge neutrality point is found to be susceptible to external strain. In the electron and hole regimes, strain influences the Landau level structure. By analyzing the intrinsic strain from the epitaxial growth and the external strain from the piezo elements and combining our experimental results with numerical simulations of strained and unstrained quantum wells, we can illustrate why the InAs/GaSb material system is regularly found to be semimetallic.

  14. Self-organized criticality as a fundamental property of neural systems.

    PubMed

    Hesse, Janina; Gross, Thilo

    2014-01-01

    The neural criticality hypothesis states that the brain may be poised in a critical state at a boundary between different types of dynamics. Theoretical and experimental studies show that critical systems often exhibit optimal computational properties, suggesting the possibility that criticality has been evolutionarily selected as a useful trait for our nervous system. Evidence for criticality has been found in cell cultures, brain slices, and anesthetized animals. Yet, inconsistent results were reported for recordings in awake animals and humans, and current results point to open questions about the exact nature and mechanism of criticality, as well as its functional role. Therefore, the criticality hypothesis has remained a controversial proposition. Here, we provide an account of the mathematical and physical foundations of criticality. In the light of this conceptual framework, we then review and discuss recent experimental studies with the aim of identifying important next steps to be taken and connections to other fields that should be explored.

  15. Self-organized criticality as a fundamental property of neural systems

    PubMed Central

    Hesse, Janina; Gross, Thilo

    2014-01-01

    The neural criticality hypothesis states that the brain may be poised in a critical state at a boundary between different types of dynamics. Theoretical and experimental studies show that critical systems often exhibit optimal computational properties, suggesting the possibility that criticality has been evolutionarily selected as a useful trait for our nervous system. Evidence for criticality has been found in cell cultures, brain slices, and anesthetized animals. Yet, inconsistent results were reported for recordings in awake animals and humans, and current results point to open questions about the exact nature and mechanism of criticality, as well as its functional role. Therefore, the criticality hypothesis has remained a controversial proposition. Here, we provide an account of the mathematical and physical foundations of criticality. In the light of this conceptual framework, we then review and discuss recent experimental studies with the aim of identifying important next steps to be taken and connections to other fields that should be explored. PMID:25294989

  16. Study of the superconducting properties of the Bi-Ca-Sr-Cu-O system

    NASA Technical Reports Server (NTRS)

    Khan, Musheer H.; Qidwai, A. A.; Zia-Ul-haq, S. M.; Binsaif, Rashid

    1990-01-01

    High Temperature Superconductivity in the Bi-Ca-Sr-Cu-O System has been observed and has attracted considerable attention in 1988. The 80 K superconductivity phase has been identified to have a composition of Bi2CaSr2Cu2Ox, while the 110 K phase as reported in the literature has a possible composition of Bi2Ca2Sr2Cu3Ox. Researchers present here a study of the electrical properties of bulk samples of the slowly cooled and rapidly quenched 2:1:2:2 system. The samples used in this study were prepared from appropriate amounts of Bi2O3, CuO, SrCO3, CaCO3.

  17. Study of the superconducting properties of the Bi-Ca-Sr-Cu-O system

    NASA Technical Reports Server (NTRS)

    Khan, Musheer H.; Naqvi, S. M. M. R.; Zia-Ul-haq, S. M.

    1991-01-01

    High Temperature Superconductivity in the Bi-Ca-Sr-Cu-O System has been observed and has attracted considerable attention in 1988. The 80 K superconductivity phase has been identified to have a composition of Bi2CaSr2Cu2Ox, while the 110 K phase as reported in the literature has a possible composition of Bi2Ca2Sr2Cu3O(x). Researchers present here a study of the electrical properties of bulk samples of the slowly cooled and rapidly quenched 2:1:2:2 system. The samples used in this study were prepared from appropriate amounts of Bi2O3, CuO, SrCO3, CaCO3.

  18. Heat-flow properties of systems with alternate masses or alternate on-site potentials.

    PubMed

    Pereira, Emmanuel; Santana, Leonardo M; Ávila, Ricardo

    2011-07-01

    We address a central issue of phononics: the search of properties or mechanisms to manage the heat flow in reliable materials. We analytically study standard and simple systems modeling the heat flow in solids, namely, the harmonic, self-consistent harmonic and also anharmonic chains of oscillators, and we show an interesting insulating effect: While in the homogeneous models the heat flow decays as the inverse of the particle mass, in the chain with alternate masses it decays as the inverse of the square of the mass difference, that is, it decays essentially as the mass ratio (between the smaller and the larger one) for a large mass difference. A similar effect holds if we alternate on-site potentials instead of particle masses. The existence of such behavior in these different systems, including anharmonic models, indicates that it is a ubiquitous phenomenon with applications in the heat flow control.

  19. Stochastic system identification of skin properties: linear and wiener static nonlinear methods.

    PubMed

    Chen, Yi; Hunter, Ian W

    2012-10-01

    Wiener static nonlinear system identification was used to study the linear dynamics and static nonlinearities in the response of skin and underlying tissue under indentation in vivo. A device capable of measuring the dynamic mechanical properties of bulk skin tissue was developed and it incorporates a custom-built Lorentz force actuator that measures the dynamic compliance between the input force (<12 N) and the output displacement (<20 mm). A simple linear stochastic system identification technique produced a variance accounted for (VAF) of 75-81% and Wiener static nonlinear techniques increased the VAF by 5%. Localized linear techniques increased the VAF to 85-95% with longer tests. Indentation experiments were conducted on 16 test subjects to determine device sensitivity and repeatability. Using the device, the coefficient of variation of test metrics was found to be as low as 2% for a single test location. The measured tissue stiffness was 300 N/m near the surface and 4.5 kN/m for high compression. The damping ranged from 5 to 23 N s/m. The bulk skin properties were also shown to vary significantly with gender and body mass index. The device and techniques used in this research can be applied to consumer product analysis, medical diagnosis and tissue research.

  20. High-Pressure Induced New Phases and Properties in Typical Molecular Systems

    NASA Astrophysics Data System (ADS)

    Cui, Tian

    2013-06-01

    High pressure introduces new phases by the rearrangement of atoms and reconfigurations of electronic states in materials, often with new physical and chemical phenomena. Study of the new phases in typical molecular systems under high pressure is an interesting subject, such as energy storage materials of solid hydrogen and polymeric nitrogen, hydrogen-rich compound with high-Tc superconductivity under high pressure, high pressure induced metallization of hydrogen, etc. High-pressure structures and pressure-induced phase transitions in the typical molecular solids, such as solid iodine, CHBr3, N2/CN, HBr/HCl, hydrogen-rich compounds (H2S, ZrH2, AsH3, BaReH9, etc.), and group IVA hydrides (Si2H6, Ge2H6, Sn2H6, etc.) are investigated extensively by means of first-principles density functional theory and extensive prediction strategies (molecular dynamics simulation, simulated annealing, soft mode phase transition, random structure-searching method and evolutionary methodology etc.). The new structures and new properties derived from pressure-induced phase transitions in these typical molecular systems have been observed. It is showed that high pressure provides a path for producing new materials with new properties.

  1. Measuring the retina optical properties using a structured illumination imaging system

    NASA Astrophysics Data System (ADS)

    Basiri, A.; Nguyen, T. A.; Ibrahim, M.; Nguyen, Q. D.; Ramella-Roman, Jessica C.

    2011-03-01

    Patients with diabetic retinopathy (DR) may experience a reduction in retinal oxygen saturation (SO2). Close monitoring with a fundus ophthalmoscope can help in the prediction of the progression of disease. In this paper we present a noninvasive instrument based on structured illumination aimed at measuring the retina optical properties including oxygen saturation. The instrument uses two wavelngths one in the NIR and one visible, a fast acquisition camera, and a splitter system that allows for contemporaneous collection of images at two different wavelengths. This scheme greatly reduces eye movement artifacts. Structured illumination was achieved in two different ways, firstly several binary illumination masks fabricated using laser micro-machining were used, a near-sinusoidal projection pattern is ultimately achieved at the image plane by appropriate positioning of the binary masks. Secondarily a sinusoidal pattern printed on a thin plastic sheet was positioned at image plane of a fundus ophthalmoscope. The system was calibrated using optical phantoms of known optical properties as well as an eye phantom that included a 150μm capillary vessel containing different concentrations of oxygenated and deoxygenated hemoglobin.

  2. Block Copolymer Modified Epoxy Amine System for Reactive Rotational Molding: Structures, Properties and Processability

    NASA Astrophysics Data System (ADS)

    Lecocq, Eva; Nony, Fabien; Tcharkhtchi, Abbas; Gérard, Jean-François

    2011-05-01

    Poly(styrene-butadiene-methylmethacrylate) (SBM) and poly(methylmethacrylate-butyle-acrylate-methylmethacrylate) (MAM) triblock copolymers have been dissolved in liquid DGEBA epoxy resin which is subsequently polymerized by meta-xylene diamine (MXDA) or Jeffamine EDR-148. A chemorheology study of these formulations by plate-plate rheology and by thermal analysis has allowed to conclude that the addition of these copolymer blocks improve the reactive rotational moulding processability without affecting the processing time. Indeed, it prevents the pooling of the formulation at the bottom of the mould and a too rapid build up of resin viscosity of these thermosetting systems. The morphology of the cured blends examined by scanning electron microscopy (SEM) shows an increase of fracture surface area and thereby a potential increase of the toughness with the modification of epoxy system. Dynamic mechanical spectroscopy (DMA) and opalescence of final material show that the block PMMA, initially miscible, is likely to induce phase separation from the epoxy-amine matrix. Thereby, the poor compatibilisation between the toughener and the matrix has a detrimental effect on the tensile mechanical properties. The compatibilisation has to be increased to improve in synergy the processability and the final properties of these block copolymer modified formulations. First attempts could be by adapting the length and ratio of each block.

  3. Cryogenic Thermoelectric Properties of the Bismuth-Magnesium and Bismuth-Antimony-Magnesium Systems

    NASA Astrophysics Data System (ADS)

    Orovets, Christine; Jin, Hyungyu; Wiendlocha, Bartlomiej; Heremans, Joseph P.

    2012-02-01

    There is a need to increase the Figure of Merit of thermoelectric materials used in low temperature cooling applications. Band structure calculations show that substitutional magnesium in bismuth can form sharp density of states peaks, suggesting the presence of a resonant level. Single crystal samples of (Bi1-xSbx)1-yMgy (0 <= x <= 12% and 0 <= y <= 0.7% nominally) were synthesized in evacuated ampoules. The composition of each ingot was analyzed using x-ray diffraction, and transport properties were measured using a Thermal Transport Option (TTO) in a Physical Properties Measurement System (PPMS) from 300K to 2K. It is apparent that the addition of magnesium strongly influences thermopower; the data for Bi90Sb10Mg0.7 shows a second minimum in thermopower at 20K, in addition to the expected minimum at approximately 50-60K. This could be due to the resonant scattering at the cryogenic temperatures which arises from the excess density of states. The addition of magnesium also appears to decrease thermal conductivity below 30K. We present systematic experimental approaches and the results to elucidate the role of magnesium in bismuth and bismuth-antimony systems.

  4. Physical Properties and Behavior of a Dense, Viscous Brine in Porous Medium Systems

    NASA Astrophysics Data System (ADS)

    Murphy, L. M.; Johnson, D. N.; Pedit, J. A.; Farthing, M. W.; Miller, C. T.

    2006-12-01

    Dense nonaqueous phase liquids (DNAPLs) are both a long-term source of groundwater contamination and a health risk to humans at low concentrations. The challenges of DNAPL remediation have led to the study of a novel mobilization-based strategy known as Brine-Based Remediation Technology (BBRT), which utilizes a dense brine to control the mobilized contaminant phase. Due to the unique application of such brines in the subsurface, there are many open issues addressing the behavior and properties of these brines in porous medium systems. To begin to address some of the open issues, a three-dimensional laboratory experiment was performed to monitor in situ density during brine barrier establishment and removal. Using a calcium bromide solution, this experiment demonstrated that a brine barrier density could be effectively established, sufficiently maintained to support common DNAPLs, and substantially recovered through active flushing. This experiment also demonstrated that highly viscous brines mound around injection wells, suggesting that an understanding of the effects of viscosity is required in flow and transport modeling. Since many flow and transport models fail to account for the physical properties of these brines, constitutive relations describing density and viscosity as a function of solute concentration were defined and incorporated into SUTRA, a model for saturated-unsaturated, variable-density groundwater flow with solute transport, to predict flow and transport of calcium bromide in a porous medium system.

  5. Hopf bifurcation analysis for a dissipative system with asymmetric interaction: Analytical explanation of a specific property of highway traffic

    NASA Astrophysics Data System (ADS)

    Nomura, Yasuyuki; Saito, Satoshi; Ishiwata, Ryosuke; Sugiyama, Yuki

    2016-01-01

    A dissipative system with asymmetric interaction, the optimal velocity model, shows a Hopf bifurcation concerned with the transition from a homogeneous motion to the formation of a moving cluster, such as the emergence of a traffic jam. We investigate the properties of Hopf bifurcation depending on the particle density, using the dynamical system for the traveling cluster solution of the continuum system derived from the original discrete system of particles. The Hopf bifurcation is revealed as a subcritical one, and the property explains well the specific phenomena in highway traffic: the metastability of jamming transition and the hysteresis effect in the relation of car density and flow rate.

  6. Hopf bifurcation analysis for a dissipative system with asymmetric interaction: Analytical explanation of a specific property of highway traffic.

    PubMed

    Nomura, Yasuyuki; Saito, Satoshi; Ishiwata, Ryosuke; Sugiyama, Yuki

    2016-01-01

    A dissipative system with asymmetric interaction, the optimal velocity model, shows a Hopf bifurcation concerned with the transition from a homogeneous motion to the formation of a moving cluster, such as the emergence of a traffic jam. We investigate the properties of Hopf bifurcation depending on the particle density, using the dynamical system for the traveling cluster solution of the continuum system derived from the original discrete system of particles. The Hopf bifurcation is revealed as a subcritical one, and the property explains well the specific phenomena in highway traffic: the metastability of jamming transition and the hysteresis effect in the relation of car density and flow rate.

  7. V and V of Lexical, Syntactic and Semantic Properties for Interactive Systems Through Model Checking of Formal Description of Dialog

    NASA Technical Reports Server (NTRS)

    Brat, Guillaume P.; Martinie, Celia; Palanque, Philippe

    2013-01-01

    During early phases of the development of an interactive system, future system properties are identified (through interaction with end users in the brainstorming and prototyping phase of the application, or by other stakehold-ers) imposing requirements on the final system. They can be specific to the application under development or generic to all applications such as usability principles. Instances of specific properties include visibility of the aircraft altitude, speed… in the cockpit and the continuous possibility of disengaging the autopilot in whatever state the aircraft is. Instances of generic properties include availability of undo (for undoable functions) and availability of a progression bar for functions lasting more than four seconds. While behavioral models of interactive systems using formal description techniques provide complete and unambiguous descriptions of states and state changes, it does not provide explicit representation of the absence or presence of properties. Assessing that the system that has been built is the right system remains a challenge usually met through extensive use and acceptance tests. By the explicit representation of properties and the availability of tools to support checking these properties, it becomes possible to provide developers with means for systematic exploration of the behavioral models and assessment of the presence or absence of these properties. This paper proposes the synergistic use two tools for checking both generic and specific properties of interactive applications: Petshop and Java PathFinder. Petshop is dedicated to the description of interactive system behavior. Java PathFinder is dedicated to the runtime verification of Java applications and as an extension dedicated to User Interfaces. This approach is exemplified on a safety critical application in the area of interactive cockpits for large civil aircrafts.

  8. Sealing properties of different obturation systems applied over apically fractured rotary nickel-titanium files.

    PubMed

    Altundasar, Emre; Sahin, Cem; Ozcelik, Bahar; Cehreli, Zafer C

    2008-02-01

    This study investigated the sealing properties of cold laterally compacted gutta percha and Thermafil applied over different apically fractured rotary nickel-titanium files. Extracted human premolars were prepared by using ProTaper (Dentsply-Maillefer, Ballaigues, Switzerland) or ProFile (Dentsply-Maillefer) systems (n = 40 for each), after which half of the specimens in each subgroup were subjected to instrument separation at the apical level. For each rotary system, roots with and without apically separated instruments (n = 10 for each) were filled with the two obturation systems and the levels of fluid conductance were recorded. In the absence of instrument separation, the leakage of Thermafil (Dentsply Maillefer) was significantly less than that achieved with cold lateral compaction (p < 0.05), whereas Thermafil yielded similar amounts of leakage in roots prepared with the ProTaper and ProFile systems (p < 0.05). Roots with fractured ProTaper instruments displayed significantly less leakage than those filled without ProTaper fragments, regardless of the obturation technique used (p < 0.05). However, intracanal separation of ProFile instruments increased the leakage (p < 0.05), but the obturation method did not influence fluid conduction (p > 0.05). These results reveal the variability of leakage associated with apically fractured ProFile and ProTaper files and different obturation methods used.

  9. Does the Agaricus blazei Murill mushroom have properties that affect the immune system? An integrative review.

    PubMed

    Lima, Cristiane Urcina Joanna Oliveira; Cordova, Cláudio Olavo de Almeida; Nóbrega, Otávio de Tolêdo; Funghetto, Silvana Schwerz; Karnikowski, Margô Gomes de Oliveira

    2011-01-01

    There has been a significant increase in the use of mushrooms for therapeutic and medicinal purposes, in particular, use of the species Agaricus blazei Murrill, a basidiomycota of Brazilian origin. The objective of this study was to identify scientific evidence regarding the influence of A. blazei Murrill on the immune system. We undertook an integrative review of indexed publications published between 2000 and 2009, using the following question as a guideline: "What evidence can be found in the literature regarding the influence of A. blazei Murrill on the immune system?" Fourteen studies verified that there is in vitro and in vivo research demonstrating this mushroom's influence on the immune system. All research was characterized as evidence level 7 (preclinical study [animals/in vitro]). The research shows that A. blazei Murrill functions through bioactive compounds via mechanisms that are not yet entirely clear, although it has been shown that they promote action on the innate and adaptive immunological response, activation of the complement system, and synthesis of pro- and anti-inflammatory cytokines and even aid in diapedesis. Despite broad scientific evidence demonstrating relevant immunomodulatory properties of A. blazei Murrill, randomized clinical trials with human subjects are still needed in order for the mushroom to be put into clinical practice.

  10. Hydrogen release properties of lithium alanate for application to fuel cell propulsion systems

    NASA Astrophysics Data System (ADS)

    Corbo, P.; Migliardini, F.; Veneri, O.

    In this paper the results of an experimental study on LiAlH 4 (lithium alanate) as hydrogen source for fuel cell propulsion systems are reported. The compound examined in this work was selected as reference material for light metal hydrides, because of its high hydrogen content (10.5 wt.%) and interesting desorption kinetic properties at moderate temperatures. Thermal dynamic and kinetic of hydrogen release from this hydride were investigated using a fixed bed reactor to evaluate the effect of heating procedure, carrier gas flow rate and sample form. The aim of this study was to characterize the lithium alanate decomposition through the reaction steps leading to the formation of Li 3AlH 6 and LiH. A hydrogen tank was designed and realized to contain pellets of lithium alanate as feeding for a fuel cell propulsion system based on a 2-kW Polymeric Electrolyte Fuel Cell (PEFC) stack. The fuel cell system was integrated into the power train comprising DC-DC converter, energy storage systems and electric drive for moped applications (3 kW). The experiments on the power train were conducted on a test bench able to simulate the vehicle behaviour and road characteristics on specific driving cycles. In particular the efficiencies of individual components and overall power train were analyzed evidencing the energy requirements of the hydrogen storage material.

  11. Effect of makeup water properties on the condenser fouling in power planr cooling system

    SciTech Connect

    Safari, I.; Walker, M.; Abbasian, J.; Arastoopour, H.; Hsieh, M-K.; Dzombak, D.; Miller, D.

    2011-01-01

    The thermoelectric power industry in the U.S. uses a large amount of fresh water. As available freshwater for use in thermoelectric power production becomes increasingly limited, use of nontraditional water sources is of growing interest. Utilization of nontraditional water, in cooling systems increases the potential for mineral precipitation on heat exchanger surfaces. In that regard, predicting the accelerated rate of scaling and fouling in condenser is crucial to evaluate the condenser performance. To achieve this goal, water chemistry should be incorporated in cooling system modeling and simulation. This paper addresses the effects of various makeup water properties on the cooling system, namely pH and aqueous speciation, both of which are important factors affecting the fouling rate in the main condenser. Detailed modeling of the volatile species desorption (i.e. CO{sub 2} and NH{sub 3}), the formation of scale in the recirculating system, and the relationship between water quality and the corresponding fouling rates is presented.

  12. Terrestrial bodies orbiter, LUNAR - A system for detailed global measurements of a planet's properties

    NASA Technical Reports Server (NTRS)

    Burke, J. D.

    1976-01-01

    The NASA Lunar Polar Orbiter, to be launched by a Delta vehicle in 1980, is designed to perform a global exploration of such moon properties as the gravity field, figure, and surface composition, as well as a lunar resource survey. The paper reviews the mission, spacecraft, and data system concepts in terms of baseline mission sequence, choice of orbits, spacecraft configuration requirements, mission sequence requirements and data system and operations. Scientific experiments planned for the Orbiter mission include geophysical altimetry and gravity experiments, heat flow experiment, magnetic field experiments, measurements of the moon's natural gamma-ray spectrum, X-ray fluorescence of lunar surface materials, sunlight reflectance spectroscopy, and spectro-stereo imaging. Characteristics of instruments designed for use in these investigations are examined. Through the use of advanced sensors and data-system techniques, coupled with well-developed spacecraft systems, the mission promises to return a very large quantity and variety of lunar data at a cost comparable with that of simpler missions in the past.

  13. Electronic and Vibrational Properties of Low-Dimensional Heterogeneous Systems: Materials and Device Perspectives

    NASA Astrophysics Data System (ADS)

    Neupane, Mahesh Raj

    Due to the aggressive miniaturization of memory and logic devices, the current technologies based on silicon have nearly reached their ultimate size limit. One method to maintain the trend in device scaling observed by Moore's law is to create a heterostructure from existing materials and utilize the underlying electronic and optical properties. Another radical approach is the conceptualization of a new device design paradigm. The central objective of this thesis is to use both of these approaches to address issues associated with the aggressive scaling of memory and logic devices such as leakage current, leakage power, and minimizing gate oxide thickness and threshold voltage. In the first part of the dissertation, an atomistic, empirical tight binding method was used to perform a systematic investigation of the effect of physical (shape and size), and material dependent (heterogenity and strain) properties on the device related electronic and optical properties of the Germanium (Ge)/Silicon (Si) nanocrystal (NC) or quantum dot (QD). The device parameters pertaining to Ge-core/Si-shell NC-based floating gate memory and optical devices such as confinement energy, retention lifetimes and optical intensities are captured and analyzed. For both the memory and optical device applications, regardless of the shape and size, the Ge-core is found to play an important role in modifying the confinement energy and carrier dynamics. However, the variation in the thickness of outer Si-shell layer had no or minimal effect on the overall device parameters. In the second part of the dissertation, we present a systematic study of the effect of atomistic heterogeneity on the vibrational properties of quasi-2D systems and recently discovered 2D materials such as graphene, while investigating their applicabilities in future devices applications. At first, we investigate the vibrational properties of an experimentally observed misoriented bilayer graphene (MBG) system, a

  14. Improvement of mechanical properties of polymeric composites: Experimental methods and new systems

    NASA Astrophysics Data System (ADS)

    Nguyen, Felix Nhanchau

    Filler- (e.g., particulate or fiber) reinforced structural polymers or polymeric composites have changed the way things are made. Today, they are found, for example, in air/ground transportation vehicles, sporting goods, ballistic barrier applications and weapons, electronic packaging, musical instruments, fashion items, and more. As the demand increases, so does the desire to have not only well balanced mechanical properties, but also light weight and low cost. This leads to a constant search for novel constituents and additives, new fabrication methods and analytical techniques. To achieve new or improved composite materials requires more than the identification of the right reinforcements to be used with the right polymer matrix at the right loading. Also, an optimized adhesion between the two phases and a toughened matrix system are needed. This calls for new methods to predict, modify and assess the level of adhesion, and new developments in matrix tougheners to minimize compromises in other mechanical/thermal properties. Furthermore, structural optimization, associated with fabrication (e.g., avoidance of fiber-fiber touching or particle aggregation), and sometimes special properties, such as electrical conductivity or magnetic susceptibility are necessary. Finally, the composite system's durability, often under hostile conditions, is generally mandatory. The present study researches new predictive and experimental methods for optimizing and characterizing filler-matrix adhesion and develops a new type of epoxy tougheners. Specifically, (1) a simple thermodynamic parameter evaluated by UNIFAC is applied successfully to screen out candidate adhesion promoters, which is necessary for optimization of the physio-chemical interactions between the two phases; (2) an optical-acoustical mechanical test assisted with an acoustic emission technique is developed to de-convolute filler debonding/delamination among many other micro failure events, and (3) novel core

  15. Efficient Visible-Light Photocatalytic Properties in Low-Temperature Bi-Nb-O System Photocatalysts.

    PubMed

    Zhai, Haifa; Shang, Shuying; Zheng, Liuyang; Li, Panpan; Li, Haiqin; Luo, Hongying; Kong, Jizhou

    2016-12-01

    Low-temperature Bi-Nb-O system photocatalysts were prepared by a citrate method using homemade water-soluble niobium precursors. The structures, morphologies, and optical properties of Bi-Nb-O system photocatalysts with different compositions were investigated deeply. All the Bi-Nb-O powders exhibit appreciably much higher photocatalytic efficiency of photo-degradation of methyl violet (MV), especially for Bi-Nb-O photocatalysts sintered at 750 °C (BNO750), only 1.5 h to completely decompose MV, and the obtained first-order rate constant (k) is 1.94/h. A larger degradation rate of Bi-Nb-O photocatalysts sintered at 550 °C (BNO550) can be attributed to the synergistic effect between β-BiNbO4 and Bi5Nb3O15. Bi5Nb3O15 with small particle size on β-BiNbO4 surface can effectively short the diffuse length of electron. BNO750 exhibits the best photocatalytic properties under visible-light irradiation, which can be attributed to its better crystallinity and the synergistic effect between β-BiNbO4 and α-BiNbO4. The small amount of α-BiNbO4 loading on surface of β-BiNbO4 can effectively improve the electron and hole segregation and migration. Holes are the main active species of Bi-Nb-O system photocatalysts in aqueous solution under visible-light irradiation.

  16. The rheological properties of self-emulsifying systems, water and microcrystalline cellulose.

    PubMed

    Newton, J M; Bazzigialuppi, M; Podczeck, F; Booth, S; Clarke, A

    2005-10-01

    The rheological properties of mixtures of equal parts of a range of ratios of a self-emulsifying system (MP) and water (W) added to microcrystalline cellulose (MCC), have been measured by an extrusion capillary rheometer. These measurements allow assessment of both the shear and tension components of flow plus the elastic behaviour of the wet powder masses, although the results for the estimation of shear stress require careful interpretation due to the limitation of the measuring system and the assumptions made in their derivation. The results indicate that there are three regions of behaviour of the systems, which are all significantly different from the mixtures containing only W and MCC. At low MP contents (1.5--23%), the masses increase in their resistance to shear and elongational flow and have lower elasticity. These similarities in behaviour occur in spite of considerable increase in the viscosity of the MPW mixtures and a change to non-Newtonian flow of the fluid. The behaviour of the 46% MP system is intermediate between these systems and the high MP concentrations (69, 80 and 92%). These latter systems show less resistance to shear and elongational flow than the first group of concentrations, but show considerably higher levels of elasticity. As the resistance to shear decreases, so does the impairment of the surface of the extrudate. There is clear evidence of a systematic change in behaviour of the wet powder masses as the values for the angle of entry of the wet mass into the die when plotted against the ratio of the resistance to die entry (upstream pressure loss) to the shear stress within the die, is linear on a log/log scale. Also, the values of compliance of the systems as a function of shear stress fall on a common curve. Changes in the ratio of the MPW to MCC for a system for a single level of MP (46%) resulted in a change in the values of the rheological parameters but not the type of behaviour. As all these wet powder masses had been shown

  17. Antioxidant properties of carnosine re-evaluated with oxidizing systems involving iron and copper ions.

    PubMed

    Mozdzan, Monika; Szemraj, Janusz; Rysz, Jacek; Nowak, Dariusz

    2005-05-01

    Carnosine has antioxidant properties and is efficient in the treatment of chemically-induced inflammatory lesions in animals. However, some studies question its biological significance as antioxidant and show lack of protection and even pro-oxidant effect of carnosine in systems containing nickel and iron ions. The ability of carnosine to: (1) reduce Fe(3+) into Fe(2+) ions; (2) protect deoxyribose from oxidation by Fe(2+)-, Fe(3+)-, and Cu(2+)-H(2)O(2)-EDTA systems; (3) protect DNA from damage caused by Cu(2+)-, and Fe(2+)-H(2)O(2)-ascorbate systems; (4) inhibit HClO- and H(2)O(2)-peroxidase-induced luminol dependent chemiluminescence was tested in vitro. At concentration 10 mM carnosine reduced 16.6+/-0.5 nmoles of Fe(3+) into Fe(2+) ions during 20 min. incubation and added to plasma significantly increased its ferric reducing ability. Inhibition of deoxyribose oxidation by 10 mM carnosine reached 56+/-5, 40+/-11 and 30+/-11% for systems containing Fe(2+), Fe(3+) and Cu(2+) ions, respectively. The damage to DNA was decreased by 84+/-9 and 61+/-14% when Cu(2+)-, and Fe(2+)-H(2)O(2)-ascorbate systems were applied. Combination of 10 mM histidine with alanine or histidine alone (but not alanine) enhanced 1.3 and 2.3 times (P<0.05) the DNA damage induced by Fe(2+)-H(2)O(2)-ascorbate. These amino acids added to 10 mM carnosine decreased 3.1-fold (P<0.05) its protective effect on DNA. Carnosine at 10 and 20 mM decreased by more than 90% light emission from both chemiluminescent systems. It is concluded that carnosine has significant antioxidant activity especially in the presence of transition metal ions. However, hydrolysis of carnosine with subsequent histidine release may be responsible for some pro-oxidant effects.

  18. Cryogenic Property Measurements on Icy Compositions with Application to Solar System Ices

    NASA Astrophysics Data System (ADS)

    Hays, C.; Castillo-Rogez, J.; Barmatz, M.; Mitchell, K.

    2007-08-01

    grains). Post-synthesis microstructural characterization will be performed using Cryogenic Optical Microscopy integrating a cross-polarizer to analyze thin sections, and a Cryogenic Scanning Electron Microscope. Mechanical property measurements on solid specimens will be performed between 80 and 270 K with a cryogenically cooled Instron measurement system. Compression measurements will be conducted as a function of temperature, strain-rate, microstructural length scale and orientation. The time dependent viscous response will be measured by performing creep measurements over the same range of temperatures. Using low-frequency cyclic loading, the dissipation factor will be measured at frequencies approaching satellite orbital frequencies. We will report preliminary mechanical property measurements of Antarctic glacial specimens at cryogenic temperatures. Fluids. In order to improve our understanding of effusive cryovolcanism, the rheological properties of liquid and mixed (slurry) materials will be measured between 80 and 300 K using a cryogenically cooled Brookfield rotational rheometer. We will report preliminary measurements of the temperature dependence of the viscous response for several compositions in the Methanol-Water System. Also, we will describe an experiment designed to measure methane wetting on water ice. These experiments will be carried out in order to explore the effects of the presence of methane lakes on Titan's surface. We are developing the capability to investigate more complex materials relevant to surface processes on Titan, including methane-ethane phase studies, hydrocarbons such as acetylene and benzene, as well as tholins and clathrates, which should exhibit a range of rheological and mechanical properties from fast-moving fluids to glacial creep. Acknowledgements: Most of the research described in this presentation was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National

  19. Systems biology of the cell cycle of Saccharomyces cerevisiae: From network mining to system-level properties.

    PubMed

    Alberghina, Lilia; Coccetti, Paola; Orlandi, Ivan

    2009-01-01

    Following a brief description of the operational procedures of systems biology (SB), the cell cycle of budding yeast is discussed as a successful example of a top-down SB analysis. After the reconstruction of the steps that have led to the identification of a sizer plus timer network in the G1 to S transition, it is shown that basic functions of the cell cycle (the setting of the critical cell size and the accuracy of DNA replication) are system-level properties, detected only by integrating molecular analysis with modelling and simulation of their underlying networks. A detailed network structure of a second relevant regulatory step of the cell cycle, the exit from mitosis, derived from extensive data mining, is constructed and discussed. To reach a quantitative understanding of how nutrients control, through signalling, metabolism and transcription, cell growth and cycle is a very relevant aim of SB. Since we know that about 900 gene products are required for cell cycle execution and control in budding yeast, it is quite clear that a purely systematic approach would require too much time. Therefore lines for a modular SB approach, which prioritises molecular and computational investigations for faster cell cycle understanding, are proposed. The relevance of the insight coming from the cell cycle SB studies in developing a new framework for tackling very complex biological processes, such as cancer and aging, is discussed.

  20. Structure, attachment properties, and ecological importance of the attachment system of English ivy (Hedera helix)

    PubMed Central

    Melzer, Björn; Seidel, Robin; Steinbrecher, Tina; Speck, Thomas

    2012-01-01

    Root climbers such as English ivy (Hedera helix) rely on specialized adventitious roots for attachment, enabling the plants to climb on a wide range of natural and artificial substrates. Despite their importance for the climbing habit, the biomechanical properties of these specialized adventitious roots compared with standard roots and their performance in the attachment to different host species or inert substrates have not been studied. Here organs and tissues involved in the attachment are characterized and their significance in regard to a broader functional and ecological aspect is discussed. Depending on the substrate, the root clusters show different types of failure modes at various frequencies, demonstrating the close interaction between the climber and its substrates. With a Young’s Modulus of 109.2 MPa, the attachment roots are relatively stiff for non-woody roots. The central cylinders of the attachment roots show a high tensile strength of 38 MPa and a very high extensibility of 34%. In host trees naturally co-distributed with English ivy, a ‘balanced’ occurrence of failure of the attachment system of the climber and the bark of the host is found, suggesting a co-evolution of climber and host. Maximum loads of root clusters normalized by the number of roots match those of individually tested attachment roots. In comparison with most subterranean roots the properties and structure of the attachment roots of English ivy show distinct differences. There exist similarities to the properties found for roots of Galium aparine, suggesting a trend in not fully self-supporting plants towards a higher extensibility. PMID:21914660

  1. Quantifying mechanical properties in a murine fracture healing system using inverse modeling: preliminary work

    NASA Astrophysics Data System (ADS)

    Miga, Michael I.; Weis, Jared A.; Granero-Molto, Froilan; Spagnoli, Anna

    2010-03-01

    Understanding bone remodeling and mechanical property characteristics is important for assessing treatments to accelerate healing or in developing diagnostics to evaluate successful return to function. The murine system whereby mid-diaphaseal tibia fractures are imparted on the subject and fracture healing is assessed at different time points and under different therapeutic conditions is a particularly useful model to study. In this work, a novel inverse geometric nonlinear elasticity modeling framework is proposed that can reconstruct multiple mechanical properties from uniaxial testing data. To test this framework, the Lame' constants were reconstructed within the context of a murine cohort (n=6) where there were no differences in treatment post tibia fracture except that half of the mice were allowed to heal 4 days longer (10 day, and 14 day healing time point, respectively). The properties reconstructed were a shear modulus of G=511.2 +/- 295.6 kPa, and 833.3+/- 352.3 kPa for the 10 day, and 14 day time points respectively. The second Lame' constant reconstructed at λ=1002.9 +/-42.9 kPa, and 14893.7 +/- 863.3 kPa for the 10 day, and 14 day time points respectively. An unpaired Student t-test was used to test for statistically significant differences among the groups. While the shear modulus did not meet our criteria for significance, the second Lame' constant did at a value p<0.0001. Traditional metrics that are commonly used within the bone fracture healing research community were not found to be statistically significant.

  2. Thermal Properties of West Siberian Sediments in Application to Basin and Petroleum Systems Modeling

    NASA Astrophysics Data System (ADS)

    Romushkevich, Raisa; Popov, Evgeny; Popov, Yury; Chekhonin, Evgeny; Myasnikov, Artem; Kazak, Andrey; Belenkaya, Irina; Zagranovskaya, Dzhuliya

    2016-04-01

    Quality of heat flow and rock thermal property data is the crucial question in basin and petroleum system modeling. A number of significant deviations in thermal conductivity values were observed during our integral geothermal study of West Siberian platform reporting that the corrections should be carried out in basin models. The experimental data including thermal anisotropy and heterogeneity measurements were obtained along of more than 15 000 core samples and about 4 500 core plugs. The measurements were performed in 1993-2015 with the optical scanning technique within the Continental Super-Deep Drilling Program (Russia) for scientific super-deep well Tyumenskaya SG-6, parametric super-deep well Yen-Yakhinskaya, and deep well Yarudeyskaya-38 as well as for 13 oil and gas fields in the West Siberia. Variations of the thermal conductivity tensor components in parallel and perpendicular direction to the layer stratification (assessed for 2D anisotropy model of the rock studied), volumetric heat capacity and thermal anisotropy coefficient values and average values of the thermal properties were the subject of statistical analysis for the uppermost deposits aged by: T3-J2 (200-165 Ma); J2-J3 (165-150 Ma); J3 (150-145 Ma); K1 (145-136 Ma); K1 (136-125 Ma); K1-K2 (125-94 Ma); K2-Pg+Ng+Q (94-0 Ma). Uncertainties caused by deviations of thermal conductivity data from its average values were found to be as high as 45 % leading to unexpected errors in the basin heat flow determinations. Also, the essential spatial-temporal variations in the thermal rock properties in the study area is proposed to be taken into account in thermo-hydrodynamic modeling of hydrocarbon recovery with thermal methods. The research work was done with financial support of the Russian Ministry of Education and Science (unique identification number RFMEFI58114X0008).

  3. Roles of Wind Shear at Different Vertical Levels, Part I: Cloud System Organization and Properties

    SciTech Connect

    Chen, Qian; Fan, Jiwen; Hagos, Samson M.; Gustafson, William I.; Berg, Larry K.

    2015-07-07

    Understanding of critical processes that contribute to the organization of mesoscale convective systems is important for accurate weather forecast and climate prediction. In this study, we investigate the effects of wind shear at different vertical levels on the organization and properties of cloud systems using the Weather Research & Forecasting (WRF) model with a spectral-bin microphysical scheme. The sensitivity experiments are performed by increasing wind shear at the lower (0-5 km), middle (5-10 km), upper (> 10 km) and the entire troposphere, respectively, based on a control run for a mesoscale convective system (MCS) with weak wind shear. We find that increasing wind shear at the both lower and middle vertical levels reduces the domain-accumulated precipitation and the occurrence of heavy rain, while increasing wind shear at the upper levels changes little on precipitation. Although increasing wind shear at the lower-levels is favorable for a more organized quasi-line system which leads to enlarged updraft core area, and enhanced updraft velocities and vertical mass fluxes, the precipitation is still reduced by 18.6% compared with the control run due to stronger rain evaporation induced by the low-level wind shear. Strong wind shear in the middle levels only produces a strong super-cell over a narrow area, leading to 67.3% reduction of precipitation over the domain. By increasing wind shear at the upper levels only, the organization of the convection is not changed much, but the increased cloudiness at the upper-levels leads to stronger surface cooling and then stabilizes the atmosphere and weakens the convection. When strong wind shear exists over the entire vertical profile, a deep dry layer (2-9 km) is produced and convection is severely suppressed. There are fewer very-high (cloud top height (CTH) > 15 km) and very-deep (cloud thickness > 15 km) clouds, and the precipitation is only about 11.8% of the control run. The changes in cloud microphysical

  4. Complement-fixing properties of antinuclear antibodies distinguish drug-induced lupus from systemic lupus erythematosus.

    PubMed

    Rubin, R L; Teodorescu, M; Beutner, E H; Plunkett, R W

    2004-01-01

    The immunofluorescence antinuclear antibody (ANA) test has been widely used to monitor autoimmune disease, but its value for diagnostic purposes is compromised by low specificity and high prevalence in disease-free individuals. The capacity of autoantibodies to fix serum complement proteins when bound to antigen is an important effector function because this property is associated with acute and chronic inflammatory processes. The current study evaluates the complement-fixing properties of antinuclear antibodies (CANA) in three well-defined and clinically-related patient groups: systemic lupus erythematosus (SLE), drug-induced lupus (DIL) and drug-induced autoimmunity (DIA). Of 20 patients diagnosed with SLE, 90% displayed complement-fixing ANA while this feature was present in only two of 18 patients with DIL and no patients with DIA without associated disease even though the mean ANA titres were similar among these patient groups. CANA was significantly correlated with anti-Sm activity. Because SLE but not DIL or DIA can be a life-threatening disease associated with complement consumption in vivo, these results demonstrate that measurement of CANA is a diagnostically useful tool and may have immunopathologic implications.

  5. The Psychometric Properties of Classroom Response System Data: A Case Study

    NASA Astrophysics Data System (ADS)

    Kortemeyer, Gerd

    2016-08-01

    Classroom response systems (often referred to as "clickers") have slowly gained adoption over the recent decade; however, critics frequently doubt their pedagogical value starting with the validity of the gathered responses: There is concern that students simply "click" random answers. This case study looks at different measures of response reliability, starting from a global look at correlations between formative clicker responses and summative examination performance to how clicker questions are used in context. It was found that clicker performance is a moderate indicator of course performance as a whole, and that while the psychometric properties of clicker items are more erratic than those of examination data, they still have acceptable internal consistency and include items with high discrimination. It was also found that clicker responses and item properties do provide highly meaningful feedback within a lecture context, i.e., when their position and function within lecture sessions are taken into consideration. Within this framework, conceptual questions provide measurably more meaningful feedback than items that require calculations.

  6. The Sm-Ni-Fe System: Isothermal Section and Microwave Absorption Properties

    NASA Astrophysics Data System (ADS)

    Yao, Qingrong; Shen, Yihao; Yang, Pengcheng; Rao, Guanghui; Zhou, Huiying; Deng, Jianqiu; Wang, Zhongmin

    2017-04-01

    The Sm-Ni-Fe ternary system has been investigated at 773 K by means of powder x-ray diffraction, metallography and scanning electron microscopy equipped with energy dispersive x-ray spectroscopy. The isothermal section consists of 16 single-phase regions, 29 two-phase regions and 14 three-phase regions. The influence of Fe-doping on the structure and the microwave absorption properties of the SmNi5 compound has been systematically studied. The homogeneity range in Sm16.67Ni83.33- x Fe x was determined as x = 16.67. The lattice parameters were found to gradually increase and the particle size become much finer with the increase of Fe concentration. All the samples exhibited good microwave absorption properties in the X-band (8-12 GHz). The highest reflection loss of the Sm16.67Ni83.33- x Fe x ( x = 0.0, 5.0, 10.0,15.0, 16.67) alloys are -10.12 dB, -10.39 dB, -16.44 dB, -20.69 dB, and -43.05 dB at 6.96 GHz, 7.92 GHz, 8.56 GHz, 10.04 GHz, and 11.08 GHz, respectively. The absorption peak shifted towards the higher frequency region with the increasing amount of Fe substitution.

  7. The biomechanical properties of the cornea in patients with systemic lupus erythematosus

    PubMed Central

    Yazici, A T; Kara, N; Yüksel, K; Altinkaynak, H; Baz, O; Bozkurt, E; Demirok, A

    2011-01-01

    Pupose: The purpose of this study was to compare the biomechanical properties of the cornea and intraocular pressure (IOP) between patients with systemic lupus erythematosis (SLE) and age-matched controls. Patients and Methods: In this prospective study, 30 healthy individuals (control group) and 30 patients with SLE (study group) underwent Reichert ocular response analyzer (ORA) measurements. In the right eye of each participant, the corneal hysteresis (CH), corneal resistance factor (CRF), and Goldman-related IOP (IOPg) were recorded using the ORA. Results: Mean CH, CRF, IOPg were significantly different between groups. Mean CH was 10.2±0.6 mm Hg in the study group and 11.3±1.3 in the control group (P=0.02); mean CRF was 9.7±1.1 mm Hg and 11.9±1.5 mm Hg, respectively (P=0.001). Mean IOPg was 13.9±2.9 mm Hg in the study group and 16.9±2.6 mm Hg in the control group (P=0.001). Conclusion: The biomechanical properties of the cornea are altered in patients with SLE compared with normal controls. These findings should be taken into account when measuring IOP values in patients with SLE as IOP readings may be underestimated in SLE eyes. PMID:21546920

  8. Antioxidant and Ex Vivo Immune System Regulatory Properties of Boswellia serrata Extracts

    PubMed Central

    Roncada, Paola

    2017-01-01

    Boswellia serrata (BS) is an important traditional medicinal plant that currently represents an interesting topic for pharmaceutical research since it possesses several pharmacological properties (e.g., anti-inflammatory, antimicrobial, and antitumour). The safety and versatility of this dietary supplement should allow for its use in numerous pathological conditions; however the quality of the extracts needs to be standardized to increase the clinical success rate resulting from its use. In the present study, different commercially available B. serrata extracts were employed to compare their AKBA content and in vitro antioxidant power. Furthermore, their ability to modulate the immune system regulatory properties was investigated. Our results showed that the AKBA content varied from 3.83 ± 0.10 to 0.03 ± 0.004%, with one sample in which it was not detectable. The highest antioxidant power and phenolic content were shown by the same extract, which also exhibited the highest AKBA concentration. Finally, the BS extracts showed the ability to influence the regulatory and effector T-cell compartments. Our results suggest that frankincense should be further investigated for its promising potentiality to modulate not only inflammation/oxidative stress but also immune dysregulation, but attention should be paid to the composition of the commercial extracts. PMID:28386311

  9. EPDM-HDPE Blends with Different Cure Systems/Mechanical and Infra-Red Spectrometric Properties

    NASA Astrophysics Data System (ADS)

    Moldovan, Zenovia; Ionescu, Florica; Litescu, Simona; Vasilescu, Ioana; Lucian Radu, Gabriel

    The physico-mechanical properties and the Infra-red (IR) spectra (obtained by applying the Attenuated Total Reflectance (ATR) technique) of high density polyethylene (HDPE)/ethylene propylene diene terpolymer (EPDM) blends were investigated using a Zwick Tensile Testing machine and a Fourier Transform Infra-red (FTIR) spectrometer. Three kinds of cure systems were used: sulfur, tetramethylthiuram disulfide (TH) and 2-mercaptobenzothiazole (M); sulfur, tetramethylthiuram disulfide (TH) and zinc-diethyldithiocarbamate (ZDEC); sulfur, tetramethylthiuram disulfide (TH) and diphenylguanidine (D). The composition of HDPE and EPDM was fixed at 50/50 by weight and the ratio cure accelerators/sulfur was varied from 0.4 to 6.34 by weight. Results indicated that polymer alloys EPDM/HDPE containing as cure agents Sulfur, TH and M, in a ratio cure accelerators/sulfur = 6.34 and 1.85, respectively, showed improved physico-mechanical properties as compared to the other polymer blends. This behavior was confirmed by the recorded ATR-FTIR spectra of the studied samples.

  10. Antioxidant and Ex Vivo Immune System Regulatory Properties of Boswellia serrata Extracts.

    PubMed

    Beghelli, Daniela; Isani, Gloria; Roncada, Paola; Andreani, Giulia; Bistoni, Onelia; Bertocchi, Martina; Lupidi, Giulio; Alunno, Alessia

    2017-01-01

    Boswellia serrata (BS) is an important traditional medicinal plant that currently represents an interesting topic for pharmaceutical research since it possesses several pharmacological properties (e.g., anti-inflammatory, antimicrobial, and antitumour). The safety and versatility of this dietary supplement should allow for its use in numerous pathological conditions; however the quality of the extracts needs to be standardized to increase the clinical success rate resulting from its use. In the present study, different commercially available B. serrata extracts were employed to compare their AKBA content and in vitro antioxidant power. Furthermore, their ability to modulate the immune system regulatory properties was investigated. Our results showed that the AKBA content varied from 3.83 ± 0.10 to 0.03 ± 0.004%, with one sample in which it was not detectable. The highest antioxidant power and phenolic content were shown by the same extract, which also exhibited the highest AKBA concentration. Finally, the BS extracts showed the ability to influence the regulatory and effector T-cell compartments. Our results suggest that frankincense should be further investigated for its promising potentiality to modulate not only inflammation/oxidative stress but also immune dysregulation, but attention should be paid to the composition of the commercial extracts.

  11. Noise property of a four-level system in vee + ladder configuration

    NASA Astrophysics Data System (ADS)

    Ming, Ying; Liu, Hong-Yu; Yang, Rong-Can

    2016-11-01

    We present the results of a theoretical study of the output amplitude noises of a four-level atomic system in vee + ladder configuration. The difference and connection of electromagnetically induced transparency and Autler-Townes splitting effects are investigated theoretically. The output amplitude noise of the probe field of two effects were compared, the quantum properties of the input field of the thin medium and the thick medium under Autler-Townes splitting or electromagnetically induced transparency (EIT) condition are maintained, the higher fidelity is obtained in the storage of the thick medium under the condition of EIT in non-classical states. The noise characteristics of the squeezed vacuum field after four-level coherent medium are studied; the noise of the output field is lowest when the detection light is far away from detuning. The double split of EIT window was made by the dynamic Stark splitting on the ground state of control field, the quantum properties of the input field in the strong-control field and strong-coupling field were maintained. The output noise spectrum is divided with the increase in the field strength, the maximum output squeezing is far away from the resonance.

  12. Biodegradable PLGA- b-PEG polymeric nanoparticles: synthesis, properties, and nanomedical applications as drug delivery system

    NASA Astrophysics Data System (ADS)

    Locatelli, Erica; Comes Franchini, Mauro

    2012-12-01

    During the past decades many synthetic polymers have been studied for nanomedicine applications and in particular as drug delivery systems. For this purpose, polymers must be non-toxic, biodegradable, and biocompatible. Polylactic- co-glycolic acid (PLGA) is one of the most studied polymers due to its complete biodegradability and ability to self-assemble into nanometric micelles that are able to entrap small molecules like drugs and to release them into body in a time-dependent manner. Despite fine qualities, using PLGA polymeric nanoparticles for in vivo applications still remains an open challenge due to many factors such as poor stability in water, big diameter (150-200 nm), and the removal of these nanocarriers from the blood stream by the liver and spleen thus reducing the concentration of drugs drastically in tumor tissue. Polyethylene glycol (PEG) is the most used polymers for drug delivery applications and the first PEGylated product is already on the market for over 20 years. This is due to its stealth behavior that inhibits the fast recognition by the immune system (opsonization) and generally leads to a reduced blood clearance of nanocarriers increasing blood circulation time. Furthermore, PEG is hydrophilic and able to stabilize nanoparticles by steric and not ionic effects especially in water. PLGA-PEG block copolymer is an emergent system because it can be easily synthesized and it possesses all good qualities of PLGA and also PEG capability so in the last decade it arose as one of the most promising systems for nanoparticles formation, drug loading, and in vivo drug delivery applications. This review will discuss briefly on PLGA- b-PEG synthesis and physicochemical properties, together with its improved qualities with respect to the single PLGA and PEG polymers. Moreover, we will focus on but in particular will treat nanoparticles formation and uses as new drug delivery system for nanomedical applications.

  13. ORBITAL AND PHYSICAL PROPERTIES OF THE σ Ori Aa, Ab, B TRIPLE SYSTEM

    SciTech Connect

    Simón-Díaz, S.; Caballero, J. A.; Apellániz, J. Maíz; Lorenzo, J.; Negueruela, I.; Dorda, R.; Marco, A.; Schneider, F. R. N.; Barbá, R. H.; Montes, D.; Pellerin, A.; Sanchez-Bermudez, J.; Sota, A.

    2015-02-01

    We provide a complete characterization of the astrophysical properties of the σ Ori Aa, Ab, B hierarchical triple system and an improved set of orbital parameters for the highly eccentric σ Ori Aa, Ab spectroscopic binary. We compiled a spectroscopic data set comprising 90 high-resolution spectra covering a total time span of 1963 days. We applied the Lehman-Filhés method for a detailed orbital analysis of the radial velocity curves and performed a combined quantitative spectroscopic analysis of the σ Ori Aa, Ab, B system by means of the stellar atmosphere code FASTWIND. We used our own plus other available information on photometry and distance to the system for measuring the radii, luminosities, and spectroscopic masses of the three components. We also inferred evolutionary masses and stellar ages using the Bayesian code BONNSAI. The orbital analysis of the new radial velocity curves led to a very accurate orbital solution of the σ Ori Aa, Ab pair. We provided indirect arguments indicating that σ Ori B is a fast-rotating early B dwarf. The FASTWIND+BONNSAI analysis showed that the Aa, Ab pair contains the hottest and most massive components of the triple system while σ Ori B is a bit cooler and less massive. The derived stellar ages of the inner pair are intriguingly younger than the one widely accepted for the σ Orionis cluster, at 3 ± 1 Ma. The outcome of this study will be of key importance for a precise determination of the distance to the σ Orionis cluster, the interpretation of the strong X-ray emission detected for σ Ori Aa, Ab, B, and the investigation of the formation and evolution of multiple massive stellar systems and substellar objects.

  14. Composition dependences of thermodynamical properties associated with Pb-free ternary, quaternary, and quinary solder systems

    NASA Astrophysics Data System (ADS)

    Dogan, A.; Arslan, H.

    2016-05-01

    In the present study, Chou's General Solution Model (GSM) has been used to predict the enthalpy and partial enthalpies of mixing of the liquid Ag-In-Sn ternary, Ag-In-Sn-Zn quaternary, and Ag-Au-In-Sn-Zn quinary systems. These are of technical importance to optimize lead-free solder alloys, in selected cross-sections: x In/ x Sn = 0.5/0.5 (ternary), Au-In0.1-Sn0.8-Zn0.1, Ag-In0.1-Sn0.8-Zn0.1 (quaternary), and t = x Au/ x In = 1, x In = x Sn = x Zn (quinary) at 1173, 773, and 773 K, respectively. Moreover, the activity of In content in the ternary alloy system Ag-In-Sn has been calculated and its result is compared with that determined from the experiment, while the activities of Ag contents associated with the alloys mentioned above have been calculated. The other traditional models such as of Colinet, Kohler, Muggianu, Toop, and Hillert are also included in calculations. Comparing those calculated from the proposed GSM with those determined from experimental measurements, it is seen that this model becomes considerably realistic in computerization for estimating thermodynamic properties in multicomponent systems.

  15. A non-contacting vertical alignment system for mass properties measuring instruments

    SciTech Connect

    James, G.H. III; Suazo, J.E.; Varga, R.C.

    1993-11-01

    A non-contact system for alignment of objects on mass properties measuring instruments is described. Test parts can be aligned to within the capabilities of the user and the fixture to make the adjustments. The current implementation can align objects to less than .001 inches at two points with final requested adjustments of a few ten-thousands of an inch. The non-contact capability allows the alignment of objects which are too compliant or fragile for traditional contacting measurement methods. Also, this system allows the definition of a reference axis on objects which are not perfectly symmetric. The reference axis is defined at the top of the object by an appropriate marker and defined at the bottom by a best fit circle through the surface at a specified height. A general description of the hardware, procedures, and results are presented for the non-user. Appendices which contain a complete description of the software, usage, and mathematical implementation are provided for the reader who is interested in using or further developing the system.

  16. Thermal Property Analysis of Axle Load Sensors for Weighing Vehicles in Weigh-in-Motion System

    PubMed Central

    Burnos, Piotr; Gajda, Janusz

    2016-01-01

    Systems which permit the weighing of vehicles in motion are called dynamic Weigh-in-Motion scales. In such systems, axle load sensors are embedded in the pavement. Among the influencing factors that negatively affect weighing accuracy is the pavement temperature. This paper presents a detailed analysis of this phenomenon and describes the properties of polymer, quartz and bending plate load sensors. The studies were conducted in two ways: at roadside Weigh-in-Motion sites and at a laboratory using a climate chamber. For accuracy assessment of roadside systems, the reference vehicle method was used. The pavement temperature influence on the weighing error was experimentally investigated as well as a non-uniform temperature distribution along and across the Weigh-in-Motion site. Tests carried out in the climatic chamber allowed the influence of temperature on the sensor intrinsic error to be determined. The results presented clearly show that all kinds of sensors are temperature sensitive. This is a new finding, as up to now the quartz and bending plate sensors were considered insensitive to this factor. PMID:27983704

  17. Effect of permafrost properties on gas hydrate petroleum system in the Qilian Mountains, Qinghai, Northwest China.

    PubMed

    Wang, Pingkang; Zhang, Xuhui; Zhu, Youhai; Li, Bing; Huang, Xia; Pang, Shouji; Zhang, Shuai; Lu, Cheng; Xiao, Rui

    2014-12-01

    The gas hydrate petroleum system in the permafrost of the Qilian Mountains, which exists as an epigenetic hydrocarbon reservoir above a deep-seated hydrocarbon reservoir, has been dynamic since the end of the Late Pleistocene because of climate change. The permafrost limits the occurrence of gas hydrate reservoirs by changing the pressure-temperature (P-T) conditions, and it affects the migration of the underlying hydrocarbon gas because of its strong sealing ability. In this study, we reconstructed the permafrost structure of the Qilian Mountains using a combination of methods and measured methane permeability in ice-bearing sediment permafrost. A relationship between the ice saturation of permafrost and methane permeability was established, which permitted the quantitative evaluation of the sealing ability of permafrost with regard to methane migration. The test results showed that when ice saturation is >80%, methane gas can be completely sealed within the permafrost. Based on the permafrost properties and genesis of shallow gas, we suggest that a shallow "gas pool" occurred in the gas hydrate petroleum system in the Qilian Mountains. Its formation was related to a metastable gas hydrate reservoir controlled by the P-T conditions, sealing ability of the permafrost, fault system, and climatic warming. From an energy perspective, the increasing volume of the gas pool means that it will likely become a shallow gas resource available for exploitation; however, for the environment, the gas pool is an underground "time bomb" that is a potential source of greenhouse gas.

  18. Accelerating Image Reconstruction in Dual-Head PET System by GPU and Symmetry Properties

    PubMed Central

    Chou, Cheng-Ying; Kao, Yu-Jiun; Wang, Weichung; Kao, Chien-Min; Chen, Chin-Tu

    2012-01-01

    Positron emission tomography (PET) is an important imaging modality in both clinical usage and research studies. We have developed a compact high-sensitivity PET system that consisted of two large-area panel PET detector heads, which produce more than 224 million lines of response and thus request dramatic computational demands. In this work, we employed a state-of-the-art graphics processing unit (GPU), NVIDIA Tesla C2070, to yield an efficient reconstruction process. Our approaches ingeniously integrate the distinguished features of the symmetry properties of the imaging system and GPU architectures, including block/warp/thread assignments and effective memory usage, to accelerate the computations for ordered subset expectation maximization (OSEM) image reconstruction. The OSEM reconstruction algorithms were implemented employing both CPU-based and GPU-based codes, and their computational performance was quantitatively analyzed and compared. The results showed that the GPU-accelerated scheme can drastically reduce the reconstruction time and thus can largely expand the applicability of the dual-head PET system. PMID:23300527

  19. Investigation of Phase Equilibria and Some Properties of Alloys of Ti-Al-Fe and Ti-Al-V Systems,

    DTIC Science & Technology

    Some data on the structure and properties of Ti-Al-Fe alloys are presented. The phase equilibria in alloys in the system Ti-Al-V were studies...However, the data available in the literature on phase equilibria in the systems Ti-Al-Fe and Ti-Al-V require refinement, as they are insufficiently

  20. Thermosetting epoxy resin/thermoplastic system with combined shape memory and self-healing properties

    NASA Astrophysics Data System (ADS)

    Yao, Yongtao; Wang, Jingjie; Lu, Haibao; Xu, Ben; Fu, Yongqing; Liu, Yanju; Leng, Jinsong

    2016-01-01

    A novel and facile strategy was proposed to construct a thermosetting/thermoplastic system with both shape memory and self-healing properties based on commercial epoxy resin and poly(ɛ-caprolactone)-PCL. Thermoplastic material is capable of re-structuring and changing the stiffness/modulus when the temperature is above melting temperature. PCL microfiber was used as a plasticizer in epoxy resin-based blends, and served as a ‘hard segment’ to fix a temporary shape of the composites during shape memory cycles. In this study, the electrospun PCL membrane with a porous network structure enabled a homogenous PCL fibrous distribution and optimized interaction between fiber and epoxy resin. The self-healing capability is achieved by phase transition during curing of the composites. The mechanism of the shape memory effect of the thermosetting (rubber)/thermoplastic composite is attributed to the structural design of the thermoplastic network inside the thermosetting resin/rubber matrix.

  1. Low Band Gap Thiophene-Perylene Diimide Systems with Tunable Charge Transport Properties

    SciTech Connect

    Balaji, Ganapathy; Kale, Tejaswini S.; Keerthi, Ashok; Della Pelle, Andrea M.; Thayumanavan, S.; Vallyaveettil, Surech

    2010-11-30

    Perylenediimide-pentathiophene systems with varied architecture of thiophene units were synthesized. The photophysical, electrochemical, and charge transport behavior of the synthesized compounds were studied. Both molecules showed a low band gap of ~1.4 eV. Surprisingly, the molecule with pentathiophene attached via β-position to the PDI unit upon annealing showed a predominant hole mobility of 1 × 10-4 cm2 V-1 s-1 whereas the compound with branched pentathiophene attached via β-position showed an electron mobility of 9.8 × 10-7 cm2 V-1 s-1. This suggests that charge transport properties can be tuned by simply varying the architecture of pentathiophene units.

  2. Compositional dependence of physical properties in Se-Sb-In glassy system

    SciTech Connect

    Sharma, Shaveta Sharma, Rita; Kumar, Praveen; Chander, Ravi; Thangaraj, R.; Mian, M.

    2015-08-28

    The growing interest in the investigation of the properties of chalcogenide glasses stems from their potential application as phase change recording media and photoconductive elements in solid state devices.In the present work, the different theoretical parameters viz. coordination number, constraints, number of lone pair electrons, bond energy, heat of atomization, mean bond energy and glass transition temperature for Se{sub 75-x}Sb{sub 25}In{sub x} (x= 0, 1, 3, 5, 7, 9, 11) chalcogenide system have been calculated and their composition variation has been discussed. It has been found that average heat of atomization increases with In content. The glass transition temperature and mean bond energy increases with In. An attempt has been made to explain the varying trend of various parameters with increasing In content.

  3. Dilute-gas properties of some systems containing CO/sub 2/

    SciTech Connect

    Ameling, W.; Lucas, K.

    1987-05-01

    The SSR-MPA potential model is used to correlate and extrapolate the dilute-gas properties of some systems containing CO/sub 2/. With parameters determined from a consistent set of second virial and Joule-Thomson data, the third virial coefficient of CO/sub 2/ as well as the second virial coefficients of various mixtures containing CO/sub 2/ can be predicted very well. The Mason-Monchik approximation fails for a complicated molecule such as CO/sub 2/, although at least a viscosity prediction of technical accuracy is obtained. If parameters fitted to the CO/sub 2/ viscosity are used, excellent predictions can be made for the viscosity of gaseous mixtures containing CO/sub 2/.

  4. Concentration dependences of the physicochemical properties of a water-acetone system

    NASA Astrophysics Data System (ADS)

    Fedyaeva, O. A.; Poshelyuzhnaya, E. G.

    2017-01-01

    Concentration dependences of the UV spectrum, refractive index, specific electrical conductivity, boiling point, pH, surface tension, and heats of dissolution of a water-acetone system on the amount of acetone in the water are studied. It is found that the reversible protolytic interaction of the components occurs in all such solutions, resulting in the formation of hydroxyl and acetonium ions. It is shown that shifts of the equilibrium between the molecules and ions in the solution leads to extreme changes in their electrical properties. It is concluded that the formation of acetone solutions of water is accompanied by heat absorption, while the formation of aqueous solutions of acetone is accompanied by heat release.

  5. Comparison between extensional rheological properties of low density polyethylene melt in SER and RME rheometric systems

    NASA Astrophysics Data System (ADS)

    Narimissa, Esmaeil; Rolón-Garrido, Víctor Hugo; Wagner, Manfred Hermann

    2015-04-01

    Precise evaluation and notional prediction of extensional rheological behaviour of polymeric melts and solutions are of significant importance in polymer industry. This is evident in the well documentation of the dominance of elongational deformation of polymeric systems in processes such as melt spinning, blow moulding, biaxial stretching of extruded sheets, etc. The relevant commercial extensional rheometers thus far discussed in the literature are RME and SER. This research, for the first time, compares the extensional viscosity measurements of low density polyethylene at 140, 150, and 170 °C through RME and SER devices. Despite the observed similarities found in this comparative investigation, the main difference was laid in maximum Hencky strain, strain hardening viscosity, and the variation of those rheological properties with testing temperature of the samples.

  6. Solvent properties governing solute partitioning in polymer/polymer aqueous two-phase systems: nonionic compounds.

    PubMed

    Madeira, Pedro P; Reis, Celso A; Rodrigues, Alírio E; Mikheeva, Larissa M; Zaslavsky, Boris Y

    2010-01-14

    The solvatochromic solvent parameters characterizing the solvent polarity (pi*), solvent hydrogen-bond donor acidity (alpha), and solvent hydrogen-bond acceptor basicity (beta) of aqueous media were measured in the coexisting phases of nine different aqueous polymer/polymer two-phase systems (ATPS), containing 0.15 M NaCl in 0.01 M phosphate buffer, pH 7.4. Partitioning coefficients of six neutral compounds were measured in the nine ATPS at particular polymer concentrations. The solvatochromic equation was used to describe the partitioning of each compound. Three descriptors of the solvent properties of the phases could describe adequately the partitioning of the solutes in all the ATPS employed.

  7. Cellular and circuit properties supporting different sensory coding strategies in electric fish and other systems.

    PubMed

    Marsat, Gary; Longtin, André; Maler, Leonard

    2012-08-01

    Neural codes often seem tailored to the type of information they must carry. Here we contrast the encoding strategies for two different communication signals in electric fish and describe the underlying cellular and network properties that implement them. We compare an aggressive signal that needs to be quickly detected, to a courtship signal whose quality needs to be evaluated. The aggressive signal is encoded by synchronized bursts and a predictive feedback input is crucial in separating background noise from the communication signal. The courtship signal is accurately encoded through a heterogenous population response allowing the discrimination of signal differences. Most importantly we show that the same strategies are used in other systems arguing that they evolved similar solutions because they faced similar tasks.

  8. Optical-response properties in levitated optomechanical systems beyond the low-excitation limit

    NASA Astrophysics Data System (ADS)

    Nie, Wenjie; Chen, Aixi; Lan, Yueheng

    2016-02-01

    We investigate the optical-response properties of a levitated optomechanical cavity coupled to a higher order excited atomic medium. The cavity field driven through the atom-field interaction is responsible for trapping a dielectric nanosphere, whose steady-state position is biased by the Coulomb force between the nanosphere and the cavity wall. We show that the phenomena of optomechanically induced transparency (OMIT) and amplification can be generated from the output probe field in the presence of an effective optomechanical coupling between the nanosphere and the cavity field. Further, the width of the transparency window increases with increasing strength of the effective optomechanical coupling, which is controlled easily by varying the Coulomb interaction and the radius of the nanosphere. In particular, when the higher order excitation of the atomic medium is included, a large driving of the atomic ensemble but a relatively small atom-field detuning can be applied to help observe the OMIT behavior in the hybrid system.

  9. Optimization of the thermodynamic properties and phase diagrams of P2O5-containing systems

    NASA Astrophysics Data System (ADS)

    Hudon, Pierre; Jung, In-Ho

    2014-05-01

    P2O5 is an important oxide component in the late stage products of numerous igneous rocks such as granites and pegmatites. Typically, P2O5 combines with CaO and crystallizes in the form of apatite, while in volatile-free conditions, Ca-whitlockite is formed. In spite of their interest, the thermodynamic properties and phase diagrams of P2O5-containg systems are not well known yet. In the case of the pure P2O5 for example, no experimental thermodynamic data are available for the liquid and the O and O' solid phases. As a result, we re-evaluated all the thermodynamic and phase diagram data of the P2O5 unary system [1]. Optimization of the thermodynamic properties and phase diagrams of the binary P2O5 systems was then performed including the Li2O-, Na2O-, MgO-, CaO-, BaO-, MnO-, FeO-, Fe2O3-, ZnO-, Al2O3-, and SiO2-P2O5 [2] systems. All available thermodynamic and phase equilibrium data were simultaneously reproduced in order to obtain a set of model equations for the Gibbs energies of all phases as functions of temperature and composition. In particular, the Gibbs energy of the liquid solution was described using the Modified Quasichemical Model [3-5] implemented in the FactSage software [6]. Thermodynamic modeling of the Li2O-Na2O-K2O-MgO-CaO-FeO-Fe2O3-Al2O3-SiO2 system, which include many granite-forming minerals such as nepheline, leucite, pyroxene, melilite, feldspar and spinel is currently in progress. [1] Jung, I.-H., Hudon, P. (2012) Thermodynamic assessment of P2O5. J. Am. Ceram. Soc., 95 (11), 3665-3672. [2] Rahman, M., Hudon, P. and Jung, I.-H. (2013) A coupled experimental study and thermodynamic modeling of the SiO2-P2O5 system. Metall. Mater. Trans. B, 44 (4), 837-852. [3] Pelton, A.D. and Blander, M. (1984) Computer-assisted analysis of the thermodynamic properties and phase diagrams of slags. Proc. AIME Symp. Metall. Slags Fluxes, TMS-AIME, 281-294. [4] Pelton, A.D. and Blander, M. (1986) Thermodynamic analysis of ordered liquid solutions by a modified

  10. Scales and properties of cold filaments in the Benguela upwelling system off Lüderitz

    NASA Astrophysics Data System (ADS)

    Hösen, Elisabeth; Möller, Judith; Jochumsen, Kerstin; Quadfasel, Detlef

    2016-03-01

    The Benguela upwelling system is one of the four strongest upwelling systems in the world. Meso-scale and submeso-scale structures like eddies and filaments build up at the front between the cold upwelled water and the warm surface water offshore. From three and a half years of satellite data (MODIS) of sea surface temperature (SST) more than 450 filaments were identified and used for extensive statistics of the scales, the occurrence frequency and the location of filaments in the Lüderitz upwelling cell and its vicinity. In situ data of SST, sea surface salinity and profiles of temperature, salinity and velocity collected during six cruises between September 2011 and February 2014 provide information on the properties of filaments and on their vertical structure. The occurrence of the filaments shows a maximum in austral summer and a minimum in September similar to the seasonal intensity of the upwelling. Within the Lüderitz cell, filaments have a meridional extent between 5 km and 80 km, an offshore extent between 20 km and more than 500 km and a vertical extent between 70 m and 180 m. The temperature within the filaments is 0.25 - 2.5°C lower than the ambient temperature and their salinity is up to 0.6 lower than the ambient salinity. Within the filaments westerly currents with velocities up to 30 cm/s were observed. Mean filament properties and occurrence result in an offshore volume transport of 3 Sv and a heat transport anomaly of -3 × 1013W.

  11. Physical properties and antibacterial activity of chitosan/acemannan mixed systems.

    PubMed

    Escobedo-Lozano, Amada Yerén; Domard, Alain; Velázquez, Carlos A; Goycoolea, Francisco M; Argüelles-Monal, Waldo M

    2015-01-22

    The aim of the present study was to investigate the mechanical and thermal properties of mixed chitosan-acemannan (CS-AC) mixed gels and the antibacterial activity of dilute mixed solutions of both polysaccharides. Physical hydrogels of chitosan comprising varying amounts of non-gelling acemannan were prepared by controlled neutralization of chitosan using ammonia. As the overall acemannan concentration in the mixed hydrogel increased while fixing that of CS, the mechanical strength decreased. These results indicate that AC perturbs the formation of elastic junctions and overall connectivity as it occurs in the isolated CS network. Heterotypic associations between CS and AC leading to the formation of more compact microdomains may be at play in reducing the density of the gel network consolidated by CS, possibly due to shorter gel junctions. Micro-DSC studies at pH 12.0 seem consistent with the suggestion that molecular heterotypic associations between CS and AC may be at play in determining the overall physical properties of the mixed gel systems. In dilute solution, CS showed antimicrobial activity against Staphylococcus aureus but not against Escherichia coli; AC did not exert antimicrobial activity against any of the two bacterial species. In blended solutions of both polysaccharides, as the amount of AC increased, the antimicrobial activity of the system against S. aureus ceased. In conclusion, this study demonstrates that it is feasible to incorporate acemannan in chitosan-acemannan gels and that although the mechanical strength decreases due to the presence of AC, the gel network persists even at high amount of AC. This study anticipates that the CS-AC mixed gels may offer promise for the future development of biomaterials such as scaffolds to be used in wound therapy.

  12. Thermoelectric properties of Mg2X (X = Si, Ge) based bulk and quantum well systems

    NASA Astrophysics Data System (ADS)

    Yelgel, Övgü Ceyda

    2017-01-01

    Mg2X (X = Si, Ge) compounds are promising thermoelectric materials for middle temperature applications due to good thermoelectric properties, nontoxicity, and abundantly available constituent elements. So far, these materials used in applications have all been in bulk form. Herein we report a full theory of thermoelectric transport properties of 3D bulk and 2D quantum well systems. The main aim of this present work is to show the effect of quantum confinement on the enhancement of the thermoelectric figure of merit theoretically. Results are given for n-type Mg2 Si0.5 Ge0.5 solid solutions and n-type Mg2Si/Mg2Ge/Mg2Si quantum well systems where the values of well widths are taken as 10 nm, 15 nm, and 20 nm, respectively. The n-type doping is made by using Sb- and La-elements as dopants. Experimental results for solid solutions are included to provide demonstration of proof of principle for the theoretical model applied for 3D bulk structures. The maximum thermoelectric figure of merits of Lax Mg2 -x Si0.49 Ge0.5 Sb0.01 solid solutions are obtained to be 0.64 and 0.56 at 800 K for x = 0 and x = 0.01 sample, respectively. While, at the same temperature, due to the relatively low phonon thermal conductivity the state-of-the-art ZT values of 2.41 and 2.26 have been attained in the Mg2Si/Mg2Ge/Mg2Si quantum well samples with 0.01 wt. % Sb-doped and 0.01 wt. % Sb- and 0.01 wt. % La-doped, respectively.

  13. Ionizable Nitroxides for Studying Local Electrostatic Properties of Lipid Bilayers and Protein Systems by EPR

    PubMed Central

    Voinov, Maxim A.; Smirnov, Alex I.

    2016-01-01

    Electrostatic interactions are known to play one of the major roles in the myriad of biochemical and biophysical processes. In this Chapter we describe biophysical methods to probe local electrostatic potentials of proteins and lipid bilayer systems that is based on an observation of reversible protonation of nitroxides by EPR. Two types of the electrostatic probes are discussed. The first one includes methanethiosulfonate derivatives of protonatable nitroxides that could be used for highly specific covalent modification of the cysteine’s sulfhydryl groups. Such spin labels are very similar in magnetic parameters and chemical properties to conventional MTSL making them suitable for studying local electrostatic properties of protein-lipid interfaces. The second type of EPR probes is designed as spin-labeled phospholipids having a protonatable nitroxide tethered to the polar head group. The probes of both types report on their ionization state through changes in magnetic parameters and a degree of rotational averaging, thus, allowing one to determine the electrostatic contribution to the interfacial pKa of the nitroxide, and, therefore, determining the local electrostatic potential. Due to their small molecular volume these probes cause a minimal perturbation to the protein or lipid system while covalent attachment secure the position of the reporter nitroxides. Experimental procedures to characterize and calibrate these probes by EPR and also the methods to analyze the EPR spectra by least-squares simulations are also outlined. The ionizable nitroxide labels and the nitroxide-labeled phospholipids described so far cover an exceptionally wide pH range from ca. 2.5 to 7.0 pH units making them suitable to study a broad range of biophysical phenomena especially at the negatively charged lipid bilayer surfaces. The rationale for selecting proper electrostatically neutral interface for calibrating such probes and example of studying surface potential of lipid bilayer is

  14. Properties and Frequency Conversion of High-Brightness Diode-Laser Systems

    NASA Astrophysics Data System (ADS)

    Boller, Klaus-Jochen; Beier, Bernard; Wallenstein, Richard

    An overview of recent developments in the field of high-power, high-brightness diode-lasers, and the optically nonlinear conversion of their output into other wavelength ranges, is given. We describe the generation of continuous-wave (CW) laser beams at power levels of several hundreds of milliwatts to several watts with near-perfect spatial and spectral properties using Master-Oscillator Power-Amplifier (MOPA) systems. With single- or double-stage systems, using amplifiers of tapered or rectangular geometry, up to 2.85 W high-brightness radiation is generated at wavelengths around 810nm with AlGaAs diodes. Even higher powers, up to 5.2W of single-frequency and high spatial quality beams at 925nm, are obtained with InGaAs diodes. We describe the basic properties of the oscillators and amplifiers used. A strict proof-of-quality for the diode radiation is provided by direct and efficient nonlinear optical conversion of the diode MOPA output into other wavelength ranges. We review recent experiments with the highest power levels obtained so far by direct frequency doubling of diode radiation. In these experiments, 100mW single-frequency ultraviolet light at 403nm was generated, as well as 1W of single-frequency blue radiation at 465nm. Nonlinear conversion of diode radiation into widely tunable infrared radiation has recently yielded record values. We review the efficient generation of widely tunable single-frequency radiation in the infrared with diode-pumped Optical Parametric Oscillators (OPOs). With this system, single-frequency output radiation with powers of more than 0.5W was generated, widely tunable around wavelengths of 2.1,m and 1.65,m and with excellent spectral and spatial quality. These developments are clear indicators of recent advances in the field of high-brightness diode-MOPA systems, and may emphasize their future central importance for applications within a vast range of optical

  15. Ice Cloud Properties in Ice-Over-Water Cloud Systems Using TRMM VIRS and TMI Data

    NASA Technical Reports Server (NTRS)

    Minnis, Patrick; Huang, Jianping; Lin, Bing; Yi, Yuhong; Arduini, Robert F.; Fan, Tai-Fang; Ayers, J. Kirk; Mace, Gerald G.

    2007-01-01

    A multi-layered cloud retrieval system (MCRS) is updated and used to estimate ice water path in maritime ice-over-water clouds using Visible and Infrared Scanner (VIRS) and TRMM Microwave Imager (TMI) measurements from the Tropical Rainfall Measuring Mission spacecraft between January and August 1998. Lookup tables of top-of-atmosphere 0.65- m reflectance are developed for ice-over-water cloud systems using radiative transfer calculations with various combinations of ice-over-water cloud layers. The liquid and ice water paths, LWP and IWP, respectively, are determined with the MCRS using these lookup tables with a combination of microwave (MW), visible (VIS), and infrared (IR) data. LWP, determined directly from the TMI MW data, is used to define the lower-level cloud properties to select the proper lookup table. The properties of the upper-level ice clouds, such as optical depth and effective size, are then derived using the Visible Infrared Solar-infrared Split-window Technique (VISST), which matches the VIRS IR, 3.9- m, and VIS data to the multilayer-cloud lookup table reflectances and a set of emittance parameterizations. Initial comparisons with surface-based radar retrievals suggest that this enhanced MCRS can significantly improve the accuracy and decrease the IWP in overlapped clouds by 42% and 13% compared to using the single-layer VISST and an earlier simplified MW-VIS-IR (MVI) differencing method, respectively, for ice-over-water cloud systems. The tropical distribution of ice-over-water clouds is the same as derived earlier from combined TMI and VIRS data, but the new values of IWP and optical depth are slightly larger than the older MVI values, and exceed those of single-layered layered clouds by 7% and 11%, respectively. The mean IWP from the MCRS is 8-14% greater than that retrieved from radar retrievals of overlapped clouds over two surface sites and the standard deviations of the differences are similar to those for single-layered clouds. Examples

  16. New epoxy/episulfide resin system for electronic and coating applications: Curing mechanisms and properties

    NASA Astrophysics Data System (ADS)

    Tsuchida, Katsuyuki

    This work involves research on a new resin system useful for printed circuit board and protective coating applications. The system provides excellent adhesion to copper and corrosion resistance for copper. The research involved detailed studies of the reaction mechanisms, and correlation of these mechanisms with the observed properties. The epoxy/episulfide system, when used with a dicyandiamide (DICY) curing agent, exhibits better adhesion to copper substrate, a better pot life and prepreg storage life, a lower thermal expansion coefficient, a lower heat of reaction, a lower degradation temperature, and higher water absorption as compared with the standard epoxy system. From model compound studies, the sulfur of the opened episulfide ring reacts with copper, resulting in a durable bond between the copper and matrix resin even after water boiling. Since the S- formed by the reaction of the episulfide with the curing agent easily reacts with both the episulfide and the epoxy, a C-S-C bond is formed and more unreacted curing agent remains as compared to the standard epoxy system. The new bond formation causes a lower thermal expansion coefficient and somewhat lower degradation temperature. The unreacted curing agent causes slightly higher water absorption. Since the episulfide ring has less stress than the epoxy ring the epoxy/episulfide system shows lower heat of reaction, i.e., a lower exotherm. and lower shrinkage. The epoxy/episuffide system, when used with a polyamide curing agent, exhibits better corrosion protection for copper substrates, a lower thermal expansion coefficient and a lower degradation temperature. From model compound studies, the curing reactions are changed by changing curing temperature and the presence of copper: the episulfide homopolymerization and the S--epoxy reactions increase in the case of room temperature curing or in the presence of copper. In the presence of copper, the sulfur of the episulfide also reacts with copper, although the

  17. Foaming properties of monoglycerol fatty acid esters in nonpolar oil systems.

    PubMed

    Shrestha, Lok Kumar; Aramaki, Kenji; Kato, Hiroyuki; Takase, Yoshihiko; Kunieda, Hironobu

    2006-09-26

    Foaming properties of monoglycerol fatty acid esters that have different alkyl chain lengths were studied in different nonpolar oils, namely liquid paraffin (LP 70), squalane, and squalene. The effect of the hydrocarbon chain length of the surfactant, the concentration, the nature of the oil, and the temperature on the nonaqueous foam stability was mainly studied. Five weight percent of glycerol alpha-monododecanoate (monolaurin) formed highly stable foams in squalane at 25 degrees C, and the foams were stable for more than 14 h. Foam stability of the monolaurin/LP 70 and the monolaurin/squalene systems are almost similar, and the foams were stable for more than 12 h. Foam stability was decreased as the hydrocarbon chain length of the monoglyceride decreased. In the glycerol alpha-monodecanoate (monocaprin)-oil systems, the foams were stable only for 3-4 h, depending on the nature of the oil. However, the foams formed in the glycerol alpha-monooctanoate (monocaprylin)-oil systems coarsened very quickly, leading to the progressive destruction of foam films, and all of the foams collapsed within a few minutes. Foam stability decreased when the oil was changed from squalane to squalene, in both monocaprin and monolaurin systems. It was observed that, in the dilute regions, these monoglycerides form fine solid dispersions in the aforementioned oils at 25 degrees C. At higher temperatures, the solid melts to isotropic single-liquid or two-liquid phases and the foams formed collapsed within 5 min. Judging from the wide-angle X-ray scattering (WAXS) and the foaming test, it is concluded that the stable foams are mainly caused by the dispersion of the surfactant solids (beta-crystal) and foam stability is largely influenced by the shape and size of the dispersed solid particles.

  18. Computer program for investigating effects of nonlinear suspension-system elastic properties on parachute inflation loads and motions

    NASA Technical Reports Server (NTRS)

    Poole, L. R.

    1972-01-01

    A computer program is presented by which the effects of nonlinear suspension-system elastic characteristics on parachute inflation loads and motions can be investigated. A mathematical elastic model of suspension-system geometry is coupled to the planar equations of motion of a general vehicle and canopy. Canopy geometry and aerodynamic drag characteristics and suspension-system elastic properties are tabular inputs. The equations of motion are numerically integrated by use of an equivalent fifth-order Runge-Kutta technique.

  19. Multiplex fluorophore systems on DNA with new diverse fluorescence properties and ability to sense the hybridization dynamics.

    PubMed

    Lee, Dong Gyu; Kim, In Sun; Park, Jung Woo; Seo, Young Jun

    2014-07-14

    We developed a multiplexed fluorophore system on a DNA scaffold (MFD) that produced new and diverse fluorescence properties depending on the mixing pattern and sequence that could not be obtained from each monomer fluorophore. Our approach for producing new fluorescence properties is relatively facile: simply mixing fluorophores on a DNA scaffold provides large variations in the color and intensity using only one excitation wavelength with high "Stokes shifts" (~190 nm). Furthermore these special fluorescence properties could be controlled by the hybridization pattern and were therefore dependent on the structural changes in DNA.

  20. Variations of Cloud and Radiative Properties of Boundary-layer and Deep Convective Systems with Sea Surface Temperature Anomalies

    NASA Technical Reports Server (NTRS)

    Xu, Kuan-Man

    2010-01-01

    Gridded monthly-mean satellite data contain compositing information from different cloud system types and clear-sky environments. To isolate the variations of cloud physical properties of an individual cloud system type with its environment, orbital data are needed. In this study, we will analyze the variations of cloud and radiative properties of boundary-layer clouds and deep convective cloud systems with sea surface temperature (SST) anomalies. We use Terra-CERES (Clouds and the Earth s Radiant Energy System) Level 2 data to classify distinct cloud objects defined by cloud-system types (deep convection, boundary-layer cumulus, stratocumulus and overcast clouds), sizes, geographic locations, and matched large-scale environments. This analysis method identifies a cloud object as a contiguous region of the Earth with a single dominant cloud-system type. It determines the shape and size of the cloud object from the satellite data and the cloud-system selection criteria. The statistical properties of the identified cloud objects are analyzed in terms of probability density functions (PDFs) of a single property or joint PDFs between two properties. The SST anomalies are defined as the differences from five-year annual-cycle means. Individual cloud objects are sorted into one of five equal size subsets, with the matched SST anomalies ranging from the most negative to the most positive values, for a given size category of deep convective cloud objects, boundary-layer cumulus, stratocumulus and overcast cloud objects. The PDFs of cloud and radiative properties for deep convective cloud objects (between 30 S and 30 N) are found to largely similar among the five SST anomaly subsets except for the lowest SST anomaly subset. The different characteristics from this SST anomaly subset may be related to some cloud objects resulting from equatorward movement of extratropical cloud systems. This result holds true for all three different size categories (measured by equivalent

  1. Properties of quantum systems via diagonalization of transition amplitudes. I. Discretization effects.

    PubMed

    Vidanović, Ivana; Bogojević, Aleksandar; Belić, Aleksandar

    2009-12-01

    We analyze the method for calculation of properties of nonrelativistic quantum systems based on exact diagonalization of space-discretized short-time evolution operators. In this paper we present a detailed analysis of the errors associated with space discretization. Approaches using direct diagonalization of real-space discretized Hamiltonians lead to polynomial errors in discretization spacing Delta . Here we show that the method based on the diagonalization of the short-time evolution operators leads to substantially smaller discretization errors, vanishing exponentially with 1/Delta(2). As a result, the presented calculation scheme is particularly well suited for numerical studies of few-body quantum systems. The analytically derived discretization errors estimates are numerically shown to hold for several models. In the follow up paper [I. Vidanović, A. Bogojević, A. Balaz, and A. Belić, Phys. Rev. E 80, 066706 (2009)] we present and analyze substantial improvements that result from the merger of this approach with the recently introduced effective-action scheme for high-precision calculation of short-time propagation.

  2. Assessment of material, structural, and functional properties of the human skeleton by pQCT systems.

    PubMed

    Roldán, Emilio J A; Bogado, César E

    2009-07-01

    Peripheral quantitative computed tomography (pQCT) systems measure bone parameters noninvasively using low radiation doses. This limits image resolution but is practical for the diagnosis and quantitative monitoring of the properties of the peripheral human skeleton. pQCT determines volumetric bone mineral density separately in trabecular and cortical bone. It may combine densitometry determinations with geometric estimates and use strain-stress indexes, and it may be used to analyze muscle variables in some areas, allowing the study of regional fragility. Experimental and clinical ex vivo studies show that pQCT variables correlate with biomechanical predictors of fragility and/or fractures. Since pQCT was approved by the US Food and Drug Administration in 1997, new skeletal regions (human femur and mandible) have been considered in the development of the system. Basically, pQCT explores intraindividual and interindividual variations in greater detail and compares the impact of skeletal diseases, risk factors, and anabolic and catabolic treatments within a given bone cross section.

  3. Inexpensive, semi-automated system for measuring mechanical properties of soft tissues.

    PubMed

    Alexander, D E; Ratzlaff, K L; Roggero, R J; Hsieh, J S

    1999-09-01

    Stiffness and strength are important properties of many tissues, but standard material-testing equipment is expensive, often ill-suited for testing soft tissues, and rarely accessible to biologists. We describe a system built around a microcomputer and an electronic balance which is particularly well-suited for measuring stress and strain in small samples of soft tissue. We use a discarded floppy disk drive as a linear actuator to strain the sample, while an electronic balance measures the tension (used to calculate stress). We give an algorithm for a program to drive a microcomputer which controls the floppy disk drive via its parallel port and records the balance measurements via its serial port. We used this system to obtain stress-strain curves from a sample of latex rubber and a sample of soft insect cuticle. Three tests of the rubber sample gave nearly identical results, with smooth, J-shaped stress-strain curves. The stress-strain curves gave a modulus elasticity value of 1.72 Mpa over the steep, straight region, well within the range for natural latex rubber. We also tested a sample of abdominal cuticle from a caterpillar (Manduca sexta). The caterpillar cuticle had a J-shaped stress-strain curve with a modulus of elasticity of 2.11 Mpa over the steep part of the curve. J. Exp. Zool. 284:374-378, 1999.

  4. Evaluating the mucoadhesive properties of drug delivery systems based on hydrated thiolated alginate.

    PubMed

    Davidovich-Pinhas, Maya; Harari, Offer; Bianco-Peled, Havazelet

    2009-05-21

    Mucoadhesive polymers have been proposed as drug delivery carriers due to their ability to adhere to the mucus layer. A relatively new class of mucoadhesive polymers, termed thiomers, was suggested as an improved carrier capable of creating disulfide covalent bond with the mucus. Since the wet physiological environment is likely to cause any delivery system to adsorb water and arrive hydrated to its target, studying the performance of mucoadhesive systems in their hydrated form is of major importance. Model thiomer, alginate-thiol, were synthesized and characterized the product using Nuclear Magnetic Resonance (NMR), Fourier Transform Infra Red spectroscopy (FTIR). The swelling behavior was determined gravimetrically and found to be affected from the thiolation. Interactions between the alginate-thiol and mucin glycoproteins, which are believed to be an outcome of disulfide bonds, were verified using rheology experiments. Adhesion of hydrated tablets with different cross linking densities to porcine's fresh small intestine tissue were characterized using a Lloyd Tensile Machine. It was shown that the thiolation did not improve the adhesion properties of hydrated tablets. It appears that the benefit achieved by adding thiol group to the polymer in dry tablet form was flawed in hydrated form due to formation of inter-molecular disulfide junctions.

  5. Magnetic properties of a metal-organic coordination system MCl2(bpy)

    NASA Astrophysics Data System (ADS)

    Yuen, Tan; Lin, Chyanlong; Li, Jing

    2001-03-01

    Room-temperature crystal structure of the transition-metal coordination polymers MCl2(bpy) (M = Fe, Co, Ni, bpy = 4, 4'-bipyridine) belongs to the orthorhombic crystal system, space group Cmmm (#65). Magnetic susceptibility M(T)/H and isothermal magnetization M(H) have been measured. Spontaneous antiferromagnetic ordering was observed in M(T)/H of all compounds, with transition temperatures 10.0 K, 5.0 K, and 8.5 K, for M = Fe, Co, and Ni, respectively. A metamagnetic transition was found in M(H) of each compound. The metamagnetic-transition critical fields for Fe, Co, and Ni compounds are 3.5 kG, 2.5 kG, and 12 kG, respectively. High temperature M(T)/H data of all compounds were fit to a modified Curie-Weiss law. The values of effective moment yielded from the fitting indicate the high spin states for all M ions. The magnetic behaviors exhibited in this system are attributed to the ferromagnetic intra-chain M-M exchange interaction through the Cl2 bridges along the c axis and the antiferromagnetic inter-chain interaction between the M ions in other directions. Particularly, the result for FeCl2(bpy) is discussed in comparison with the magnetic properties of Fe(N3)2(bpy) and other related polymers.

  6. EXPERIMENTAL STUDY ON SHOCK RELIEF PROPERTY OF FALL PROTECTION SYSTEM BY IMPROVED SCAFFOLD SHEETING

    NASA Astrophysics Data System (ADS)

    Ohdo, Katsutoshi; Takanashi, Seiji; Hino, Yasumichi; Takahashi, Hiroki; Toyosawa, Yasuo

    The frequency of fall accidents is one of the most serious problems in construction industries, and the countermeasures, such as guidelines or regulation, etc., for falls from scaffolds have been tightened in Japan. These countermeasures particularly affect the decrease in the number of the fatal accidents by falls from scaffolds. However, the rate of such accidents from falls is still high in the construction industries. In order to reduce the falls, the scaffold sheeting, as a covering around the scaffolds to protect against falling construction materials (a method widely used in Japan), was improved for fall protection. In this study, the safety of the fall protection system by the improved sheeting and the regulation was compared by fall tests using a human dummy. Then, impact loads, which acted on the scaffolds, were measured and evaluated for the safety property. Form the results of the fall tests, it could be confirmed that the fall protection system by the improved scaffold sheeting was relieved the impact loads more than that by the Japanese regulation.

  7. Open system of interacting fermions: statistical properties of cross sections and fluctuations.

    PubMed

    Celardo, G L; Izrailev, F M; Zelevinsky, V G; Berman, G P

    2007-09-01

    Statistical properties of cross sections are studied for an open system of interacting fermions. The description is based on the effective non-Hermitian Hamiltonian that accounts for the existence of open decay channels preserving the unitarity of the scattering matrix. The intrinsic interaction is modeled by the two-body random ensemble of variable strength. In particular, the crossover region from isolated to overlapping resonances accompanied by the effect of the width redistribution creating superradiant and trapped states is studied in detail. The important observables, such as average cross section, its fluctuations, autocorrelation functions of the cross section, and scattering matrix, are very sensitive to the coupling of the intrinsic states to the continuum around the crossover. A detailed comparison is made of our results with standard predictions of statistical theory of cross sections, such as the Hauser-Feshbach formula for the average cross section and Ericson theory of fluctuations and correlations of cross sections. Strong deviations are found in the crossover region, along with the dependence on intrinsic interactions and the degree of chaos inside the system.

  8. Mean state and kinematic properties of mesoscale convective systems over West Africa

    NASA Astrophysics Data System (ADS)

    Ogungbenro, Stephen B.; Ajayi, V. O.; Adefolalu, D. O.

    2016-04-01

    A 17-year (1984 to 2000) dataset of brightness temperature (T b) was employed to study the spatial and temporal scales of mesoscale convective systems (MCS) over West Africa. The kinematic properties of MCS were tested using wind products. A threshold brightness temperature (T b) of ≤213 K and spatial coverage specifications of more than 5000 km2 were used as two set criteria for initiating MCS tracking. MCS occurrences vary in seasons and locations over West Africa, and their activities vary with different weather zones. They can appear at any time of the day, but this study revealed a significant preference for early morning hours and night hours over continental West Africa. The well-organized systems occur between July and September in the Sahel, and between May and September in the Savanna band. MCS activities in the Gulf of Guinea peak between March and April, while the Savanna and Sahel zones peak between June and August. The produced annual atlas gives a spatial account of areas of MCS dominance in West Africa. The presence of African Easterly Jet (AEJ) and Tropical Easterly Jet (TEJ), and deep monsoon depth all characterize an environment where MCS thrive. Kinematic study of a typical MCS reveals that the monsoon depth increases at the passage of MCS, with cyclonic vorticity dominating from the surface to 300 hpa while anticyclonic vorticity was observed around 200 hpa, and this confirms the importance of low level convergence and upper level divergence as the major requirements for storm mobilization and maintenance.

  9. Influence of reverse bias on the LEDs properties used as photo-detectors in VLC systems

    NASA Astrophysics Data System (ADS)

    Kowalczyk, Marcin; Siuzdak, Jerzy

    2015-09-01

    Continuous increasing share of light emitting diodes (LEDs) in a lighting market, which we observe during the last couple years, opens new possibilities. Especially, when we talk about practical realization the concept of visible light communications (VLC), which gains on popularity recently. The VLC concept presupposes utilization of illumination systems for a purpose of data transmission. It means, the emitters, in this case the LEDs, will not of a light source only, but also the data transmitters. Currently, most of the conducted researches in this area is concentrated on achievement of effective transmission methods. It means a transmission only in one direction. This is not enough, when we talk about the fully functional transmission system. Ensuring of feedback transmission channel is a necessary also. One of the ideas, which was postulated by authors of this article, is using for this purpose the LEDs in a double role. A utilization of LEDs as photo-detectors requires a reverse polarization, in contrast to a forward bias, which has a place when they work as light emitters. Ensuring of proper polarization get significant meaning. The article presents the investigations results on the influence of reverse bias on photo-receiving properties of LEDs used as light detectors. The conducted research proved that an improvement of sensitivity and bandwidth parameters are possible by application of appropriate value of the reverse voltage in a receiver.

  10. EMTA’s Evaluation of the Elastic Properties for Fiber Polymer Composites Potentially Used in Hydropower Systems

    SciTech Connect

    Nguyen, Ba Nghiep; Paquette, Joshua

    2010-08-01

    Fiber-reinforced polymer composites can offer important advantages over metals where lightweight, cost-effective manufacturing and high mechanical performance can be achieved. To date, these materials have not been used in hydropower systems. In view of the possibility to tailor their mechanical properties to specific applications, they now have become a subject of research for potential use in hydropower systems. The first step in any structural design that uses composite materials consists of evaluating the basic composite mechanical properties as a function of the as-formed composite microstructure. These basic properties are the elastic stiffness, stress-strain response, and strength. This report describes the evaluation of the elastic stiffness for a series of common discontinuous fiber polymer composites processed by injection molding and compression molding in order to preliminarily estimate whether these composites could be used in hydropower systems for load-carrying components such as turbine blades. To this end, the EMTA (Copyright © Battelle 2010) predictive modeling tool developed at the Pacific Northwest National Laboratory (PNNL) has been applied to predict the elastic properties of these composites as a function of three key microstructural parameters: fiber volume fraction, fiber orientation distribution, and fiber length distribution. These parameters strongly control the composite mechanical performance and can be tailored to achieve property enhancement. EMTA uses the standard and enhanced Mori-Tanaka type models combined with the Eshelby equivalent inclusion method to predict the thermoelastic properties of the composite based on its microstructure.

  11. Effects of chemical alteration on fracture mechanical properties in hydrothermal systems

    NASA Astrophysics Data System (ADS)

    Callahan, O. A.; Eichhubl, P.; Olson, J. E.

    2015-12-01

    Fault and fracture networks often control the distribution of fluids and heat in hydrothermal and epithermal systems, and in related geothermal and mineral resources. Additional chemical influences on conduit evolution are well documented, with dissolution and precipitation of mineral species potentially changing the permeability of fault-facture networks. Less well understood are the impacts of chemical alteration on the mechanical properties governing fracture growth and fracture network geometry. We use double-torsion (DT) load relaxation tests under ambient air conditions to measure the mode-I fracture toughness (KIC) and subcritical fracture growth index (SCI) of variably altered rock samples obtained from outcrop in Dixie Valley, NV. Samples from southern Dixie Valley include 1) weakly altered granite, characterized by minor sericite in plagioclase, albitization and vacuolization of feldspars, and incomplete replacement of biotite with chlorite, and 2) granite from an area of locally intense propylitic alteration with chlorite-calcite-hematite-epidote assemblages. We also evaluated samples of completely silicified gabbro obtained from the Dixie Comstock epithermal gold deposit. In the weakly altered granite KIC and SCI are 1.3 ±0.2 MPam1/2 (n=8) and 59 ±25 (n=29), respectively. In the propylitic assemblage KIC is reduced to 0.6 ±0.1 MPam1/2 (n=11), and the SCI increased to 75 ±36 (n = 33). In both cases, the altered materials have lower fracture toughness and higher SCI than is reported for common geomechanical standards such as Westerly Granite (KIC ~1.7 MPam1/2; SCI ~48). Preliminary analysis of the silicified gabbro shows a significant increase in fracture toughness, 3.6 ±0.4 MPam1/2 (n=2), and SCI, 102 ±45 (n=19), compared to published values for gabbro (2.9 MPam1/2 and SCI = 32). These results suggest that mineralogical and textural changes associated with different alteration assemblages may result in spatially variable rates of fracture

  12. Properties of superconducting Bi-Sr-Ca-Cu-O system remelted under higher gravity conditions

    NASA Astrophysics Data System (ADS)

    Volkov, M. P.; Melekh, B. T.; Parfeniev, R. V.; Kartenko, N. F.; Regel, L. L.; Turchaninov, A. M.

    1992-04-01

    The structure and magnetic properties of high Tc superconductor Bi-Sr-Ca-Cu-O samples remelted under 1 g0, 8 g0 and 12 g0 gravity levels have been investigated. Superconducting properties make a change along the ingots. The dependence of structural and superconducting properties on the gravity level and their time degradation have been observed.

  13. Physical Properties of the Saturnian Ring System Inferred from Cassini VIMS Opposition Observations

    NASA Astrophysics Data System (ADS)

    Hapke, B.; Nelson, R. M.; Brown, R. H.; Spilker, L. J.; Smythe, W. D.; Kamp, L.; Boryta, M.; Leader, F.; Matson, D. L.; Edgington, S.; Nicholson, P. D.; Filacchione, G.; Clark, R. N.; Bibring, J.; Baines, K. H.; Buratti, B. J.; Bellucci, G.; Capaccioni, F.; Cerroni, P.; Combes, M.; Coradini, A.; Cruikshank, D. P.; Drossart, P.; Formisano, V.; Jaumann, R.; Langevin, Y.; McCord, T.; Menella, V.; Sicardy, B.

    2005-12-01

    Much can be learned about the nature of Saturn's ring particles and their regoliths by studying the wavelength dependence of their reflectance as a function of phase angle. At small phase angles the reflectance of the rings exhibits the opposition effect (OE) a significant increase in reflectance as phase angle approaches zero degrees. The wavelength dependence of the width and the peak of the OE are indicators of important physical properties of the regoliths of the ring particles such as particle size, particle shape, packing density and albedo. The Cassini VIMS multi spectral imaging spectrometer obtained low phase observations of the Saturnian ring system from 0.4-5.2 microns during 2005. These data clearly show a pronounced (OE). Cassini VIMS opposition surge data indicate a wavelength dependence of the OE that relates to the size and separation of the scattering centers on the surface of the ring particles. Laboratory studies and theoretical models of the OE relate the size and shape of the reflectance increase to physical properties of the medium (Nelson et al, 2002; Spilker et al. 1995; Hapke et al., 1993)). The OE arises from two processes, shadow hiding (SH) and coherent backscattering (CB). The SHOE is observed because shadows cast by the particulate grains on one another are eliminated as phase angle approaches zero degrees. The CBOE is due to constructive interference between light rays traveling in opposite paths through the medium as the path length decreases with decreasing phase angle. The VIMS data at 1.9 microns, where the rings are highly reflective, indicate a strong CBOE effect, however, at 2.1 microns, where the rings are very absorbing, the shape of the phase curve is consistent with SHOE. Hapke et al. 1993,Science, 260, 509-511 Nelson, R. M. et al., 2002. Planetary and Space Science, 50, 849-856 Spilker aka Horn, L.J et al., 1995. IAU Colloquium #150 This work done at JPL under contract with NASA

  14. Generation of Individual Diversity: A Too Neglected Fundamental Property of Adaptive Immune System

    PubMed Central

    Muraille, Eric

    2014-01-01

    The fitness gains resulting from development of the adaptive immune system (AIS) during evolution are still the subject of hot debate. A large random repertoire of antigenic receptors is costly to develop and could be the source of autoimmune reactions. And yet, despite their drawbacks, AIS-like systems seem to have been independently acquired in several phyla of metazoans with very different anatomies, longevities, and lifestyles. This article is a speculative attempt to explore the selective pressures, which favored this striking convergent evolution. It is well known that the AIS enables an organism to produce a specific immune response against all natural or artificial antigenic structures. However, it is frequently neglected that this response is highly variable among individuals. In practice, each individual possesses a “private” adaptive immune repertoire. This individualization of immune defenses implies that invasion and escape immune mechanisms developed by pathogens will certainly not always be successful as the specific targets and organization of the immune response are somewhat unpredictable. In a population, where individuals display heterogeneous immune responses to infection, the probability that a pathogen is able to infect all individuals could be reduced compared to a homogeneous population. This suggests that the individual diversity of the immune repertoire is not a by-product of the AIS but of its fundamental properties and could be in part responsible for repeated selection and conservation of the AIS during metazoan evolution. The capacity of the AIS to improve the management of cooperative or parasitic symbiotic relationships at the individual level could be a secondary development due to its progressive integration into the innate immune system. This hypothesis constitutes a new scenario for AIS emergence and explains the selection of MHC restriction and MHC diversification. PMID:24860570

  15. Generation of individual diversity: a too neglected fundamental property of adaptive immune system.

    PubMed

    Muraille, Eric

    2014-01-01

    The fitness gains resulting from development of the adaptive immune system (AIS) during evolution are still the subject of hot debate. A large random repertoire of antigenic receptors is costly to develop and could be the source of autoimmune reactions. And yet, despite their drawbacks, AIS-like systems seem to have been independently acquired in several phyla of metazoans with very different anatomies, longevities, and lifestyles. This article is a speculative attempt to explore the selective pressures, which favored this striking convergent evolution. It is well known that the AIS enables an organism to produce a specific immune response against all natural or artificial antigenic structures. However, it is frequently neglected that this response is highly variable among individuals. In practice, each individual possesses a "private" adaptive immune repertoire. This individualization of immune defenses implies that invasion and escape immune mechanisms developed by pathogens will certainly not always be successful as the specific targets and organization of the immune response are somewhat unpredictable. In a population, where individuals display heterogeneous immune responses to infection, the probability that a pathogen is able to infect all individuals could be reduced compared to a homogeneous population. This suggests that the individual diversity of the immune repertoire is not a by-product of the AIS but of its fundamental properties and could be in part responsible for repeated selection and conservation of the AIS during metazoan evolution. The capacity of the AIS to improve the management of cooperative or parasitic symbiotic relationships at the individual level could be a secondary development due to its progressive integration into the innate immune system. This hypothesis constitutes a new scenario for AIS emergence and explains the selection of MHC restriction and MHC diversification.

  16. Solid solution directionally solidified eutectics: Model systems for structure-property relationships in interfacial fracture

    NASA Astrophysics Data System (ADS)

    Brewer, Luke Nathaniel

    The next generation of high temperature materials for application in aerospace and power generation systems will be required to withstand temperatures well in excess of 1200°C, often in oxidizing atmospheres. Oxide-oxide directionally solidified eutectics (DSE's) have shown promise as high temperature ceramic materials, only to be limited by their lack of fracture toughness at room temperature. In the case of DSE oxide materials, the interfacial fracture behavior has been blamed for the poor performance in the past and is the subject of interest in this work. In this thesis, the solid solution, directionally solidified quaternary eutectic (SS-DSE), Co1-xNixO/ZrO2(CaO), is developed as a model system for the study of interfacial fracture in oxide-oxide DSE's. A variety of structural and mechanical characterization techniques are applied to investigate structure-property relationships for interfacial fracture behavior. The optical floating zone technique was employed for growing both the eutectic crystals and their single crystal counterparts, Co1-x NixO. Co1-xNixO/ZrO2(CaO) was shown to possess the necessary structural elements to serve as a model system for interfacial fracture. Lamellar microstructures were observed for all compositions. The crystallographic relationships between phases evolved as a model solid solution. Interdiffusion of chemical species was minimal, allowing the layers to treated independently. The core of this thesis is dedicated to studying the nature of interfacial fracture behavior in oxide eutectics. This study is motivated by the novel observation of extensive interfacial delamination for the system CoO/ZrO 2(CaO). A transition from interfacial delamination to interfacial penetration is observed for compositions of Co1-xNixO/ZrO 2(CaO) with x > 0.2. The residual stress state in these materials was investigated using X-ray and neutron diffraction-based techniques. The role of plasticity in interfacial fracture was explored using a

  17. Sperry low-temperature geothermal conversion system. Volume 1: Organic-working-fluid properties

    NASA Astrophysics Data System (ADS)

    Carroll, C.; Hules, K. R.; Langley, R.; Toekes, B.; Wilson, D. P.

    1981-11-01

    Measurements of the physical properties of R-114 refrigerant in the compressed liquid and dense gas regions are reported. Included are: experimental studies of the thermodynamic properties of R-114, enthalpy measurement by throttling experiment, engineering model of the thermodynamic properties of R-114, feasibility study to dissociate R-114 with a four cycle gasoline engine, transport properties of R-114, analytical procedure to determine impurities in R-114, toxicological information on Freons, and a literature search of published properties of R-114, other refrigerants, and other potential working fluids.

  18. THERMODYNAMIC PROPERTIES OF THE METALLIC SYSTEM Au(111)-(3×3)R30∘-Pd

    NASA Astrophysics Data System (ADS)

    Chadli, R.; Kheffache, S.; Khater, A.

    2016-02-01

    This work constitutes an analysis of the thermodynamic properties in the ordered metallic surface alloy system Au(111)-(3×3)R30∘-Pd. The equilibrium structural characteristics as well as the thermodynamic functions are examined by the matching method, associated with real space Green’s function formalism, evaluated in the harmonic approximation. Our numerical results, for this metallic system of surface alloy, show in particular a significant dependence between the thermodynamic properties and the coordination number and the values of the force constants.

  19. Modeling of carbon fiber couch attenuation properties with a commercial treatment planning system.

    PubMed

    Mihaylov, I B; Corry, P; Yan, Y; Ratanatharathorn, V; Moros, E G

    2008-11-01

    The purpose of this work is to evaluate the modeling of carbon fiber couch attenuation properties with a commercial treatment planning system (TPS, Pinnacle3, v8.0d). A carbon fiber couch (Brain-Lab) was incorporated into the TPS by automatic contouring of all transverse CT slices. The couch shape and dimensions were set according to the vendor specifications. The couch composition was realized by assigning appropriate densities to the delineated contours. The couch modeling by the TPS was validated by absolute dosimetric measurements. A phantom consisting of several solid water slabs was CT scanned, the CT data set was imported into the TPS, and the carbon fiber couch was auto-contoured. Open (unblocked) field plans for different gantry angles and field sizes were generated. The doses to a point at 3 cm depth, placed at the linac isocenter, were computed. The phantom was irradiated according to the dose calculation setup and doses were measured with an ion chamber. In addition, percent depth dose (PDD) curves were computed as well as measured with radiographic film. The calculated and measured doses, transmissions, and PDDs were cross-compared. Doses for several posterior fields (0 degree, 30 degrees, 50 degrees, 75 degrees, 83 degrees) were calculated for 6 and 18 MV photon beams. For model validation a nominal field size of 10 x 10 cm2 was chosen and 100 MU were delivered for each portal. The largest difference between computed and measured doses for those posterior fields was within 1.7%. A comparison between computed and measured transmissions for the aforementioned fields was performed and the results were found to agree within 1.1%. The differences between computed and measured doses for different field sizes, ranging from 5 x 5 cm2 to 25 x 25 cm2 in 5 cm increments, were within 2%. Measured and computed PDD curves with and without the couch agree from the surface up to 30 cm depth. The PDDs indicate a surface dose increase resulting from the carbon fiber

  20. Vibroseismic-Streamer Systems to Image Sub-Ice Properties and Englacial Layering on Large Scales

    NASA Astrophysics Data System (ADS)

    Diez, A.; Eisen, O.; Lambrecht, A.; Christoph, M.; Hofstede, C. M.; Kristoffersen, Y.; Blenkner, R.; Hilmarsson, S.

    2014-12-01

    recommendation which set-up to use for which scientific questions and areas of interest. Our surveys demonstrate the potential to image englacial layering and sub-ice features and, thus, help increase our understanding of subglacial and englacial properties by the application of such an operational vibroseismic system.

  1. A critical appraisal of the zero-multipole method: Structural, thermodynamic, dielectric, and dynamical properties of a water system

    NASA Astrophysics Data System (ADS)

    Wang, Han; Nakamura, Haruki; Fukuda, Ikuo

    2016-03-01

    We performed extensive and strict tests for the reliability of the zero-multipole (summation) method (ZMM), which is a method for estimating the electrostatic interactions among charged particles in a classical physical system, by investigating a set of various physical quantities. This set covers a broad range of water properties, including the thermodynamic properties (pressure, excess chemical potential, constant volume/pressure heat capacity, isothermal compressibility, and thermal expansion coefficient), dielectric properties (dielectric constant and Kirkwood-G factor), dynamical properties (diffusion constant and viscosity), and the structural property (radial distribution function). We selected a bulk water system, the most important solvent, and applied the widely used TIP3P model to this test. In result, the ZMM works well for almost all cases, compared with the smooth particle mesh Ewald (SPME) method that was carefully optimized. In particular, at cut-off radius of 1.2 nm, the recommended choices of ZMM parameters for the TIP3P system are α ≤ 1 nm-1 for the splitting parameter and l = 2 or l = 3 for the order of the multipole moment. We discussed the origin of the deviations of the ZMM and found that they are intimately related to the deviations of the equilibrated densities between the ZMM and SPME, while the magnitude of the density deviations is very small.

  2. PROPERTIES OF THE CLOSE-IN TERTIARY IN THE QUADRUPLE SYSTEM V401 CYG

    SciTech Connect

    Zhu, L.-Y.; Qian, S.-B.; Zhou, X.; Li, L.-J.; Zhao, E.-G.; Liu, L.; Liu, N.-P.

    2013-08-01

    V401 Cyg is a quadruple system in which the spectroscopic signature of a close-in tertiary and a distant visual companion star were reported. Orbital properties of the close-in companion should provide valuable information on the formation of close binaries and stellar dynamical interaction. By analyzing new times of minimum light together with those collected from the literature, we discovered that the observed-calculated (O - C) curve of V401 Cyg shows a cyclic change with a short period of 3.5 yr and a semi-amplitude of 0.00436 days while it undergoes an upward parabolic variation. Those photoelectric and CCD data covered more than two cycles and were analyzed for the light-travel time effect via the presence of the tertiary companion. The mass of the third body was determined to be M{sub 3}sin i' = 0.65({+-} 0.08) M{sub Sun }, which is close to the value estimated from the spectroscopic data (M{sub 3} {approx} 0.64 M{sub Sun }). This reveals that the orbital inclination of the tertiary was about i' {approx} 90 Degree-Sign , indicating that the contact components of V401 Cyg have the possibility of being eclipsed by the tertiary at an orbital distance of about 3.0 AU, and it may be a triply eclipsing hierarchical triple system. The upward parabolic change indicates a period increase at a rate of (P-dot{sub 2} = 1.5 x 10{sup -7} revealing a mass transfer from the secondary to the primary (M-dot{sub 2} = 5.9 x 10{sup -8} M{sub Sun} yr{sup -1}). This is consistent with the predictions of the theory of thermal relaxation oscillation (TRO) suggesting that V401 Cyg is undergoing an expanding-orbit stage in the TRO cycles.

  3. Photochemical and microbial alterations of DOM spectroscopic properties in the estuarine system Ria de Aveiro.

    PubMed

    Santos, L; Santos, E B H; Dias, J M; Cunha, A; Almeida, A

    2014-08-01

    The influence of photochemical transformations of chromophoric dissolved organic matter (CDOM) on microbial communities was evaluated in the estuarine system Ria de Aveiro. Two sites, representative of the marine and brackish water zones of the estuary, were surveyed regularly in order to determine seasonal and vertical profiles of variation of CDOM properties. Optical parameters of CDOM indicative of aromaticity and molecular weight were used to establish CDOM sources, and microbial abundance and activity was characterized. Additionally, microcosm experiments were performed in order to simulate photochemical reactions of CDOM and to evaluate microbial responses to light-induced changes in CDOM composition. The CDOM of the two estuarine zones showed different spectral characteristics, with significantly higher values of the specific ultra-violet absorbance at 254 nm (SUVA254) (5.5 times) and of the absorption coefficient at 350 nm (a350) (12 times) and lower SR (S275-295/S350-400) ratio at brackish water compared with the marine zone, reflecting the different amounts and prevailing sources of organic matter, as well as distinct riverine and oceanic influences. At the marine zone, the abundance of bacteria and the activity of Leu-AMPase correlated with a350 and a254, suggesting a microbial contribution to the HMW CDOM pool. The irradiation of DOM resulted in a decrease of the values of a254 and a350 and an increase of the slope S275-295 and of the ratios E2 : E3 (a250/a365) and SR, which in turn increase its bioavailability. However, the extent of photoinduced transformations and microbial responses was dependent on the initial optical characteristics of CDOM. In Ria de Aveiro both photochemical and microbial processes yielded optical changes in CDOM and the overall results of these combined processes determine the fate of CDOM in the estuarine system and have an influence on local productivity and in adjacent coastal areas.

  4. Photophysical properties and photostability of novel benzothiazole-based D- π- A- π- D systems

    NASA Astrophysics Data System (ADS)

    Cigáň, Marek; Gáplovský, Anton; Gajdoš, Peter; Magdolen, Peter; Zahradník, Pavol; Vetríková, Zuzana

    2010-12-01

    The photophysical properties and photochemical stability of two novel D- π- A- π- D systems based on a benzothiazole core and terminal N, N-dimethylaminophenyl and N, N-diphenylaminophenyl groups were investigated. The quantum yield of photoreactions ( Φ) was determined for various oxygen concentrations in the solvent (CH 2Cl 2) and various irradiation wavelengths. Trans- cis photoisomerization is proposed as a photobleaching mechanism during irradiation at longer wavelength due to charge-transfer transitions. Solution deoxygenation led to an unusual decrease in the photostability of the compounds investigated, most likely because of cation radical formation. The population of higher excited states for short-wavelength irradiation opened another degradation pathway and the overall degradation percentage decreased in comparison with long-wavelength irradiation. We assume that photoisomerization of the second double bond and electron transfer to CH 2Cl 2 (and subsequent oxidation reactions) contribute to this slower degradation branch. Singlet oxygen contributes significantly, albeit to the smallest values of Φ, to the overall photodegradation for both types of irradiation.

  5. Circulating tumor cell is a common property of brain glioma and promotes the monitoring system

    PubMed Central

    Gao, Faliang; Cui, Yong; Jiang, Haihui; Sui, Dali; Wang, Yonggang; Jiang, Zhongli; Zhao, Jizong; Lin, Song

    2016-01-01

    Brain glioma is the most common primary intracranial tumor characterized by dismal prognosis and frequent recurrence, yet a real-time and reliable biological approach to monitor tumor response and progression is still lacking. Recently, few studies have reported that circulating tumor cells (CTCs) could be detected in glioblastoma multiform (GBM), providing the possibility of its application in brain glioma monitoring system. But its application limits still exist, because the detection rate of CTCs is still low and was exclusively limited to high- grade gliomas. Here, we adopted an advanced integrated cellular and molecular approach of SE-iFISH to detect CTCs in the peripheral blood (PB) of patients with 7 different subtypes of brain glioma, uncovering the direct evidences of glioma migration. We identified CTCs in the PB from 24 of 31 (77%) patients with glioma in all 7 subtypes. No statistical difference of CTC incidence and count was observed in different pathological subtypes or WHO grades of glioma. Clinical data revealed that CTCs, to some extent, was superior to MRI in monitoring the treatment response and differentiating radionecrosis from recurrence of glioma. Conclusively, CTCs is a common property of brain gliomas of various pathological subtypes, which has provided an ultimate paradox for the hypothesis “soil and seed”. It can be used to monitor the microenvironment of gliomas dynamically, which will be a meaningful complement to radiographic imaging. PMID:27517490

  6. The stabilities, electronic structures and elastic properties of Rb—As systems

    NASA Astrophysics Data System (ADS)

    Havva Bogaz, Ozisik; Kemal, Colakoglu; Engin, Deligoz; Haci, Ozisik

    2012-04-01

    The structural, electronic and elastic properties of Rb—As systems (RbAs in NaP, LiAs and AuCu structures, RbAs2 in the MgCu2 structure, Rb3As in Na3As, Cu3P and Li3Bi structures, and Rb5As4 in the A5B4 structure) are investigated with the generalized gradient approximation in the frame of density functional theory. The lattice parameters, cohesive energies, formation energies, bulk moduli and the first derivatives of the bulk moduli (to fit Murnaghan's equation of state) of the considered structures are calculated and reasonable agreement is obtained. In addition, the phase transition pressures are also predicted. The electronic band structures, the partial densities of states corresponding to the band structures and the charge density distributions are presented and analysed. The second-order elastic constants based on the stress-strain method and other related quantities such as Young's modulus, the shear modulus, Poisson's ratio, sound velocities, the Debye temperature and shear anisotropy factors are also estimated.

  7. Phase coexistence in a triolein-phosphatidylcholine system. Implications for lysosomal membrane properties.

    PubMed

    Pakkanen, Kirsi I; Duelund, Lars; Vuento, Matti; Ipsen, John Hjort

    2010-02-01

    The effects of tri- and monoglycerides on phospholipid (POPC) membranes were studied using spectroscopical methods. Triolein was found to form two types of POPC-rich membranes, both with POPC or as a three-component system with monopalmitin. These two membrane types were determined as co-existing phases based on their spontaneous and stable separation and named heavy and light phase according to their sedimentation behaviour. Marked differences were seen in the physical properties of these phases, even though only minor compositional variation was detected. The light, less polar phase was found to be less ordered and more fluid and seemed to allow significantly lower amount of water penetration into the membrane-water interface than pure POPC membrane. The heavy phase, apart from their slightly altered water penetration, resembled more a pure POPC membrane. As triglycerides are present in lysosomal membranes, the present results can be seen as an implication for polarity-based water permeability barrier possibly contributing to the integrity of lysosomes.

  8. Pharmacokinetic Properties of Adenosine Amine Congener in Cochlear Perilymph after Systemic Administration.

    PubMed

    Chang, Hao; Telang, Ravindra S; Sreebhavan, Sreevalsan; Tingle, Malcolm; Thorne, Peter R; Vlajkovic, Srdjan M

    2017-01-01

    Noise-induced hearing loss (NIHL) is a global health problem affecting over 5% of the population worldwide. We have shown previously that acute noise-induced cochlear injury can be ameliorated by administration of drugs acting on adenosine receptors in the inner ear, and a selective A1 adenosine receptor agonist adenosine amine congener (ADAC) has emerged as a potentially effective treatment for cochlear injury and resulting hearing loss. This study investigated pharmacokinetic properties of ADAC in rat perilymph after systemic (intravenous) administration using a newly developed liquid chromatography-tandem mass spectrometry detection method. The method was developed and validated in accordance with the USA FDA guidelines including accuracy, precision, specificity, and linearity. Perilymph was sampled from the apical turn of the cochlea to prevent contamination with the cerebrospinal fluid. ADAC was detected in cochlear perilymph within two minutes following intravenous administration and remained in perilymph above its minimal effective concentration for at least two hours. The pharmacokinetic pattern of ADAC was significantly altered by exposure to noise, suggesting transient changes in permeability of the blood-labyrinth barrier and/or cochlear blood flow. This study supports ADAC development as a potential clinical otological treatment for acute sensorineural hearing loss caused by exposure to traumatic noise.

  9. Experimental determination of the correlation properties of plasma turbulence using 2D BES systems

    NASA Astrophysics Data System (ADS)

    Fox, M. F. J.; Field, A. R.; van Wyk, F.; Ghim, Y.-c.; Schekochihin, A. A.; the MAST Team

    2017-04-01

    A procedure is presented to map from the spatial correlation parameters of a turbulent density field (the radial and binormal correlation lengths and wavenumbers, and the fluctuation amplitude) to correlation parameters that would be measured by a beam emission spectroscopy (BES) diagnostic. The inverse mapping is also derived, which results in resolution criteria for recovering correct correlation parameters, depending on the spatial response of the instrument quantified in terms of point-spread functions (PSFs). Thus, a procedure is presented that allows for a systematic comparison between theoretical predictions and experimental observations. This procedure is illustrated using the Mega-Ampere Spherical Tokamak BES system and the validity of the underlying assumptions is tested on fluctuating density fields generated by direct numerical simulations using the gyrokinetic code GS2. The measurement of the correlation time, by means of the cross-correlation time-delay method, is also investigated and is shown to be sensitive to the fluctuating radial component of velocity, as well as to small variations in the spatial properties of the PSFs.

  10. Pharmacokinetic Properties of Adenosine Amine Congener in Cochlear Perilymph after Systemic Administration

    PubMed Central

    Sreebhavan, Sreevalsan; Thorne, Peter R.

    2017-01-01

    Noise-induced hearing loss (NIHL) is a global health problem affecting over 5% of the population worldwide. We have shown previously that acute noise-induced cochlear injury can be ameliorated by administration of drugs acting on adenosine receptors in the inner ear, and a selective A1 adenosine receptor agonist adenosine amine congener (ADAC) has emerged as a potentially effective treatment for cochlear injury and resulting hearing loss. This study investigated pharmacokinetic properties of ADAC in rat perilymph after systemic (intravenous) administration using a newly developed liquid chromatography-tandem mass spectrometry detection method. The method was developed and validated in accordance with the USA FDA guidelines including accuracy, precision, specificity, and linearity. Perilymph was sampled from the apical turn of the cochlea to prevent contamination with the cerebrospinal fluid. ADAC was detected in cochlear perilymph within two minutes following intravenous administration and remained in perilymph above its minimal effective concentration for at least two hours. The pharmacokinetic pattern of ADAC was significantly altered by exposure to noise, suggesting transient changes in permeability of the blood-labyrinth barrier and/or cochlear blood flow. This study supports ADAC development as a potential clinical otological treatment for acute sensorineural hearing loss caused by exposure to traumatic noise. PMID:28194422

  11. Properties of the V-type ATPase from the excretory system of the usherhopper, Poekilocerus bufonius.

    PubMed

    Al-Fifi, Z I A; Al-Robai, A; Khoja, S M

    2002-09-01

    The bafilomycin A(1) and N-ethylmaleimide (NEM)-sensitive (V-type) ATPase was partially purified from the apical membrane-rich fractions of excretory system (Malpighian tubules and hind gut) of P. bufonius. Enzymatic activity was inhibited by bafilomycin A(1) (IC(50) = 1.3 nM) and NEM (IC(50) = 10.1 microM). The V-type ATPase activity is confined to the apical membrane fraction, while the activity of Na(+)/K(+) -ATPase forms the major part of the basal membrane fraction. The optimal pH required for maximal activity of V-type ATPase was pH 7.5. The effect of 30 mM of various salts on ATPase activity was investigated. NaCl and KCl caused increases of 175% and 184%, respectively. Other chloride salts also caused an increase in activity in the following ascending order: RbCl, LiCI, choline Cl, NaCI, KCl and tris-HCl. The activity of V-type ATPase was stimulated by a variety of different anions and cations, and HCO(3)(-) was found to be the most potent cationic activator of ATPase activity. The present results show that the properties of V-type ATPase of P. bufonius are similar to those reported for other insect tissues.

  12. Room temperature shear properties of the strain isolator pad for the shuttle thermal protection system

    NASA Technical Reports Server (NTRS)

    Sawyer, J. W.; Waters, W. A., Jr.

    1981-01-01

    Tests were conducted at room temperature to determine the shear properties of the strain isolator pad (SIP) material used in the thermal protection system of the space shuttle. Tests were conducted on both the .23 cm and .41 cm thick SIP material in the virgin state and after fifty fully reversed shear cycles. The shear stress displacement relationships are highly nonlinear, exhibit large hysteresis effects, are dependent on material orientation, and have a large low modulus region near the zero stress level where small changes in stress can result in large displacements. The values at the higher stress levels generally increase with normal and shear force load conditioning. Normal forces applied during the shear tests reduces the low modulus region for the material. Shear test techniques which restrict the normal movement of the material give erroneous stress displacement results. However, small normal forces do not significantly effect the shear modulus for a given shear stress. Poisson's ratio values for the material are within the range of values for many common materials. The values are not constant but vary as a function of the stress level and the previous stress history of the material. Ultimate shear strengths of the .23 cm thick SIP are significantly higher than those obtained for the .41 cm thick SIP.

  13. Influence of different crosslinking systems on the mechanical and morphological properties of thermoplastic vulcanizates

    NASA Astrophysics Data System (ADS)

    Patermann, Simone; Altstädt, Volker

    2015-05-01

    Thermoplastic vulcanizates (TPVs) combine the elastic properties of thermoset cross-linked rubbers with the melt processability of thermoplastics. The most representative examples of this class are the TPVs based on polypropylene (PP) and ethylene-propylene-diene terpolymer rubber (EPDM). The PP/EPDM blends were produced by dynamic vulcanization in a continuous extrusion process. The influence of different crosslinking systems was studied with regard to cross-link density, compression set, tensile strength/elongation at break and morphology. With increasing peroxide concentration, the cross-link density increases, leading to a reduction of the compression set by 50 %. The same improvement is only reachable with twice the concentration of phenolic resin. Only the peroxide cross-linked blends show smaller dispersed EPDM particles with increasing peroxide concentration. With a peroxide concentration between 0.2 and 0.5 wt. %, a maximum in tensile strength and elongation at break was found. For the phenolic resin cross-linked blends, the tensile strength stays almost constant with increasing phenolic resin concentration and the elongation at break shows best results at 0.5 wt. % phenolic resin. Compared to batch processes, the results show different values, but comparable trends.

  14. Vibrational properties at the ordered metallic surface alloy system Au(110)-1×2-Pd

    NASA Astrophysics Data System (ADS)

    Kheffache, Sedik; Chadli, Rabah; Khater, Antoine

    2016-06-01

    We present a calculation for the vibrational properties of the ordered surface alloy Au(110)-1×2-Pd on a crystalline substrate of Au. The surface phonon dispersion curves and the local vibrations densities of states (LDOS) are calculated in the harmonic approximation for the system, using the phase field matching theory (PFMT) method and associated real space Green’s functions. In particular, it is shown that the surface alloy presents optic vibrational modes above the Au bulk bands, along the directions of high-symmetry ΓX¯, XS¯, SY¯ and Y Γ¯ of the corresponding two-dimensional Brillouin zone. Measurements of the surface phonon dispersion branches can hence be made by different techniques such as helium atom scattering (HAS) to compare with. The calculated LDOS for Au and Pd atomic sites in the four top surface atomic layers span a wider range of frequencies than those for the individual Au(110) or Pd(110) metallic surfaces. These LDOS provide a spectral signature for the progressive transition from the surface dynamics to that of the Au crystal bulk. Knowledge of these LDOS for the surface alloy can also serve as an input for modeling the diffusion and reaction rates of chemical species at its surface.

  15. Structural and thermoelectric properties of SiGe/Al multilayer systems during metal induced crystallization

    NASA Astrophysics Data System (ADS)

    Lindorf, M.; Rohrmann, H.; Span, G.; Raoux, S.; Jordan-Sweet, J.; Albrecht, M.

    2016-11-01

    While the process of metal induced crystallization (MIC) is widely used in the fabrication of thin film electronic devices, its application to the field of thermoelectrics is fairly new. Especially, its implementation in the field of the classic thermoelectric material SiGe could lead to a low cost approach by combining the benefits of low thermal budget, self-doping, and thin film and sputter deposition compatibility. In this work, samples consisting of SiGe/Al multilayers deposited on aluminum oxide based substrates have been prepared. Special emphasis was put on the ratio of Al to SiGe and the resulting changes in transport properties during annealing. On one hand, a certain amount of Al is needed to ensure a complete MIC process for the SiGe, but on the other hand, an excess of Al results in a metallic system with low thermoelectric efficiency. In-situ characterization during annealing of the samples was carried out via x-ray diffraction, electrical resistivity, and Seebeck measurements.

  16. Statistical properties of nanosized clusters on a surface in overdamped stochastic reaction-Cattaneo systems

    NASA Astrophysics Data System (ADS)

    Kharchenko, Vasyl O.; Kharchenko, Dmitrii O.; Dvornichenko, Alina V.

    2014-12-01

    In this work we study an overdamped stochastic reaction-Cattaneo model describing nanosized pattern formation on a surface at monolayer deposition. We study and compare an influence of both primary and secondary mechanisms onto pattern formation processes. The primary mechanisms relate to the rates of chemical reactions and interaction strength of adsorbate; the secondary mechanisms are related to finite atomic disturbance propagation speed and stochastic contribution satisfying fluctuation-dissipation relation. Considering statistical properties of surface structures we discuss transitions between homogeneous phases related to low and high density states. We illustrate that these transitions are accompanied by a formation of adsorbate or vacancy islands. It was found that spherical adsorbate and vacancy islands are characterized by different distribution functions over their sizes for different symmetry of substrate lattice. We have shown that depending on system control parameters island size distributions can change their modality. The size of localized nano-clusters can be controlled by both primary and secondary mechanisms of pattern formation.

  17. Investigations on the usefulness of the Massively Parallel Processor for study of electronic properties of atomic and condensed matter systems

    NASA Technical Reports Server (NTRS)

    Das, T. P.

    1988-01-01

    The usefulness of the Massively Parallel Processor (MPP) for investigation of electronic structures and hyperfine properties of atomic and condensed matter systems was explored. The major effort was directed towards the preparation of algorithms for parallelization of the computational procedure being used on serial computers for electronic structure calculations in condensed matter systems. Detailed descriptions of investigations and results are reported, including MPP adaptation of self-consistent charge extended Hueckel (SCCEH) procedure, MPP adaptation of the first-principles Hartree-Fock cluster procedure for electronic structures of large molecules and solid state systems, and MPP adaptation of the many-body procedure for atomic systems.

  18. Different Properties of the \\varvec{bar{K}NN} and \\varvec{bar{K}bar{K}N} Systems

    NASA Astrophysics Data System (ADS)

    Shevchenko, N. V.

    2017-03-01

    A series of exact or accurate three-body calculations of different properties of the bar{K}NN and bar{K}bar{K}N systems is described. In particular, binding energies and widths of the quasi-bound states in the systems were calculated. Near-threshold elastic K^- d amplitudes were also found together with the 1 s level shift and width of kaonic deuterium. Different dependences of the three-body results on two-body inputs are discussed.

  19. Effect of c-f hybridization on electric and magnetic properties of some Heavy Fermion (HF) systems

    NASA Astrophysics Data System (ADS)

    Sahoo, J.; Nayak, P.

    2017-02-01

    Representing the heavy fermion systems by the Periodic Anderson Model (PAM), we have used Zubarev technique to see the effect of c-f hybridization on the temperature dependence of resistivity and magnetic susceptibility. The calculated resistivity and magnetic susceptibility show the general features observed in these materials experimentally. Further, we have shown how the strength of hybridization as well as the position of the f-level affects both the properties and the Kondo temperature of these systems.

  20. Effects of certain key metrics of hydroentanglement system on properties of nonwoven fabrics made with commercially cleaned greige cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research was conducted to determine the effects of certain key process metrics of a commercial-grade hydroentanglement system on properties of the nonwoven fabrics made with cleaned Upland greige cotton lint. The metrics studied, among others, were the hydroentangling water pressure, the strip orif...

  1. Quantification of the uncertainty in estimates of climate system properties due to differences in available reconstructions of historical data

    NASA Astrophysics Data System (ADS)

    Forest, C. E.; Libardoni, A.; Sokolov, A. P.

    2013-12-01

    Climate models of intermediate complexity have been used extensively to help determine climate system properties because of their efficiency and ability to easily adjust key climate system components. By comparing model output over a wide range of possible states of the climate with observations, probability distributions for climate system properties can be derived. Observational data for a number of climate variables are available, and in many cases multiple reconstructions are available for the same variable. This study first evaluates how differences in the estimated historical trends of upper-air temperatures translate into uncertainty in estimates of three climate system properties: climate sensitivity, the rate of ocean heat uptake, and net aerosol forcing. These results build upon previous work that explored similar estimates associated with trends in surface temperatures and ocean heat content. Also addressed in this study is quantifying uncertainties in the estimates of the three properties associated with how surface temperature observations are used in the estimation process. Other studies have estimated climate parameters using only global mean surface temperature trends. It is shown here that estimates of all parameters are dependent upon the spatial variation of surface temperature trends. In particular, lower estimates of climate sensitivity are shown to be inconsistent with most observational data sources when using latitude-dependent surface trends. Low climate sensitivity is also shown to lead to inconsistent patterns in ocean heat uptake. These results will be presented in the context of recent investigations using data from previous work by the authors.

  2. An efficient monte carlo method for calculating the equilibrium properties for a quantum system coupled strongly to a classical one

    NASA Astrophysics Data System (ADS)

    Carmeli, Benny; Metiu, Horia

    1987-02-01

    We calculate the equilibrium properties of a system consisting of two strongly interacting quantum and classical subsystems, by using a fast Fourier transform method to evaluate the quantum contribution and a Monte Carlo method to evaluate the contribution of the classical part. The method is applied to a model relevant to tunneling problems.

  3. Cancer cell growth and survival as a system-level property sustained by enhanced glycolysis and mitochondrial metabolic remodeling

    PubMed Central

    Alberghina, Lilia; Gaglio, Daniela; Gelfi, Cecilia; Moresco, Rosa M.; Mauri, Giancarlo; Bertolazzi, Paola; Messa, Cristina; Gilardi, Maria C.; Chiaradonna, Ferdinando; Vanoni, Marco

    2012-01-01

    Systems Biology holds that complex cellular functions are generated as system-level properties endowed with robustness, each involving large networks of molecular determinants, generally identified by “omics” analyses. In this paper we describe four basic cancer cell properties that can easily be investigated in vitro: enhanced proliferation, evasion from apoptosis, genomic instability, and inability to undergo oncogene-induced senescence. Focusing our analysis on a K-ras dependent transformation system, we show that enhanced proliferation and evasion from apoptosis are closely linked, and present findings that indicate how a large metabolic remodeling sustains the enhanced growth ability. Network analysis of transcriptional profiling gives the first indication on this remodeling, further supported by biochemical investigations and metabolic flux analysis (MFA). Enhanced glycolysis, down-regulation of TCA cycle, decoupling of glucose and glutamine utilization, with increased reductive carboxylation of glutamine, so to yield a sustained production of growth building blocks and glutathione, are the hallmarks of enhanced proliferation. Low glucose availability specifically induces cell death in K-ras transformed cells, while PKA activation reverts this effect, possibly through at least two mitochondrial targets. The central role of mitochondria in determining the two investigated cancer cell properties is finally discussed. Taken together the findings reported herein indicate that a system-level property is sustained by a cascade of interconnected biochemical pathways that behave differently in normal and in transformed cells. PMID:22988443

  4. 32 CFR 37.605 - What is the general policy on participants' financial, property, and purchasing systems?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT REGULATIONS TECHNOLOGY INVESTMENT AGREEMENTS... management, property management, and purchasing systems than they currently use for: (a) Expenditure-based... business, if they have no expenditure-based Federal procurement contracts and assistance awards....

  5. 32 CFR 37.605 - What is the general policy on participants' financial, property, and purchasing systems?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 1 2012-07-01 2012-07-01 false What is the general policy on participants' financial, property, and purchasing systems? 37.605 Section 37.605 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT REGULATIONS TECHNOLOGY INVESTMENT...

  6. Comparing slip behavior and hydromechanical properties of fault systems in the Nankai subduction zone

    NASA Astrophysics Data System (ADS)

    Ikari, M.; Saffer, D. M.; Marone, C.; Knuth, M. W.

    2010-12-01

    At subduction zones, the plate boundary system includes several active faults, including the master décollement and splay faults that branch from it and cut the overriding margin wedge. The partitioning of strain accumulation and slip on these structures may provide important information about the mechanical behavior of the plate boundary, and for earthquake rupture and tsunamigenesis. We conducted laboratory experiments to measure the frictional and hydrologic properties of fault and wall rock from three distinct fault zone systems sampled during IODP Expedition 316 and ODP Leg 190 to the Nankai Trough offshore Japan. These fault zones are: (1) a major out-of-sequence thrust fault that terminates ~25 km landward of the trench and extends for >120 km along-strike, termed the “megasplay”; (2) the frontal thrust, comprising a region of diffuse thrust faulting near the trench; and (3) the décollement zone sampled 2 km from the trench. We observe predominantly low friction (µ ≤ 0.46), and low permeability (k ≤ 7.00x10-19 m2) consistent with the clay-rich composition of the samples. Samples from the décollement zone are both consistently weaker (µ ≤ 0.30) and less permeable than those from the megasplay area and the frontal thrust system. Fault zone material from the megasplay is both significantly weaker and less permeable than the surrounding wall rocks, a pattern not observed in the frontal thrust and décollement. All samples exhibit velocity-strengthening frictional behavior over most of the experimental conditions we explored, consistent with aseismic slip at shallow depths. Slip stability does not vary between fault zone and wall rock in any of the three settings. A previously observed minimum in the friction rate parameter a-b at sliding velocities of ~1-3 µm/s (~0.1-0.3 m/d) for samples from the megasplay fault zone is also observed for both the frontal thrust and décollement, and our data suggests that this phenomenon may be controlled

  7. Scales and properties of cold filaments in the southern Benguela upwelling system

    NASA Astrophysics Data System (ADS)

    Hösen, Elisabeth; Möller, Judith; Jochumsen, Kerstin; Quadfasel, Detlef

    2015-04-01

    The Benguela upwelling system is one of the four most active upwelling systems in the world. Meso-scale and submeso-scale structures like eddies and filaments are build up, due to instabilities at the front between the cold upwelled water and the warm surface water offshore. The heat exchange across the front is carried out mainly by such structures, especially filaments due to their offshore extent. Therefore cold upwelling filaments play an important role in the heat budget of the south-east Atlantic. This study is focussed on the southern part of the Benguela upwelling system, especially on the upwelling cell off Lüderitz. We combine satellite data and ship-borne measurements to investigate the appearance of such filaments and their properties (vertical and horizontal extent, mean temperature anomaly, mean velocity etc.). We use infra-red measurements of the MODIS satellite from 2011 to 2014. Two cruises in the region of interest were carried out in August 2013 and February 2014 and provide highly resolved surface data of temperature and salinity as well as vertical information on temperature, salinity and velocity. The spatial and temporal distribution of the filaments including the meridional and longitudinal extent is determined using a frequency analysis (wavelet analysis) of our data sets. Most filaments occurred between 25°S and 27°S, corresponding to the position of the Lüderitz cell. The observed filaments have a meridional extent between 5km and 44km and propagate more than 20km offshore. The lifetime of a filament is between 2 and 12 days. The time series of satellite data provides information on the seasonal and year-to-year variability in the appearance of filaments. Additionally the variability of the forcing winds is analysed and results are connected to the appearance of filaments. The filament activity is highest in southern summer, corresponding to the main upwelling season. The ship-borne measurements allow a highly resolved analysis of the

  8. Ultracold fermionic few-body systems in reduced dimensions: Static and dynamic properties

    NASA Astrophysics Data System (ADS)

    Gharashi, Seyed Ebrahim

    Much progress has been made in the preparation and manipulation of tunable ultracold atomic samples over the last three decades. Small samples of ultracold 6Li atoms, e.g., have been prepared experimentally in effectively one-dimensional geometries. The study of few-atom samples is particularly interesting since they serve as building blocks of many-body systems. This thesis studies static and dynamic properties of ultracold fermionic few-body systems. A Lippmann-Schwinger equation based approach is utilized to obtain highly-accurate energies and eigenfunctions of two-component Fermi gases with interspecies zero-range interactions consisting of up to four particles under one-dimensional harmonic confinement. The resulting energy spectra agree quite well with the experimentally measured ones. For infinitely-strong repulsive interaction, the eigenfunctions of the system, which are populated by adiabatically increasing the interaction strength from 0 to infinity, differ from the eigenfunctions obtained through a generalized Fermi-Fermi mapping, indicating shortcomings of the generalized Fermi-Fermi mapping. The correlations of the "upper branch" reveal, in resemblance with Stoner ferromagnetism, a competition between the repulsive interspecies interaction and the effective repulsion due to the Pauli exclusion principle. Full three-dimensional calculations are performed to assess the applicability regime of strictly one-dimensional models. Moreover, the full three-dimensional energy spectra are utilized to determine the third-order virial coefficient, which plays an important role in determining the equation of state in the high-temperature regime as functions of the interaction strength and confinement geometry. Motivated by recent experiments, the tunneling dynamics of two interacting one-dimensional 6Li atoms is simulated within a full time-dependent framework. It is shown that a WKB based trap calibration is, in general, inaccurate and an alternative trap

  9. Physical properties of the WASP-67 planetary system from multi-colour photometry

    NASA Astrophysics Data System (ADS)

    Mancini, L.; Southworth, J.; Ciceri, S.; Calchi Novati, S.; Dominik, M.; Henning, Th.; Jørgensen, U. G.; Korhonen, H.; Nikolov, N.; Alsubai, K. A.; Bozza, V.; Bramich, D. M.; D'Ago, G.; Figuera Jaimes, R.; Galianni, P.; Gu, S.-H.; Harpsøe, K.; Hinse, T. C.; Hundertmark, M.; Juncher, D.; Kains, N.; Popovas, A.; Rabus, M.; Rahvar, S.; Skottfelt, J.; Snodgrass, C.; Street, R.; Surdej, J.; Tsapras, Y.; Vilela, C.; Wang, X.-B.; Wertz, O.

    2014-08-01

    Context. The extrasolar planet WASP-67 b is the first hot Jupiter definitively known to undergo only partial eclipses. The lack of the second and third contact points in this planetary system makes it difficult to obtain accurate measurements of its physical parameters. Aims: By using new high-precision photometric data, we confirm that WASP-67 b shows grazing eclipses and compute accurate estimates of the physical properties of the planet and its parent star. Methods: We present high-quality, multi-colour, broad-band photometric observations comprising five light curves covering two transit events, obtained using two medium-class telescopes and the telescope-defocusing technique. One transit was observed through a Bessel-R filter and the other simultaneously through filters similar to Sloan g'r'i'z'. We modelled these data using jktebop. The physical parameters of the system were obtained from the analysis of these light curves and from published spectroscopic measurements. Results: All five of our light curves satisfy the criterion for being grazing eclipses. We revise the physical parameters of the whole WASP-67 system and, in particular, significantly improve the measurements of the planet's radius (Rb = 1.091 ± 0.046 RJup) and density (ρb = 0.292 ± 0.036 ρJup), as compared to the values in the discovery paper (Rb = 1.4 -0.2+0.3 RJup and ρb = 0.16 ± 0.08 ρJup). The transit ephemeris was also substantially refined. We investigated the variation of the planet's radius as a function of the wavelength, using the simultaneous multi-band data, finding that our measurements are consistent with a flat spectrum to within the experimental uncertainties. Based on data collected with GROND at the MPG 2.2 m telescope and DFOSC at the Danish 1.54 m telescope.Full Table 2 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/568/A127

  10. Quantum theory of the electronic and optical properties of low-dimensional semiconductor systems

    NASA Astrophysics Data System (ADS)

    Lau, Wayne Heung

    This thesis examines the electronic and optical properties of low-dimensional semiconductor systems. A theory is developed to study the electron-hole generation-recombination process of type-II semimetallic semiconductor heterojunctions based on a 3 x 3 k·p matrix Hamiltonian (three-band model) and an 8 x 8 k·p matrix Hamiltonian (eight-band model). A novel electron-hole generation and recombination process, which is called activationless generation-recombination process, is predicted. It is demonstrated that the current through the type-II semimetallic semiconductor heterojunctions is governed by the activationless electron-hole generation-recombination process at the heterointerfaces, and that the current-voltage characteristics are essentially linear. A qualitative agreement between theory and experiments is observed. The numerical results of the eight-band model are compared with those of the threeband model. Based on a lattice gas model, a theory is developed to study the influence of a random potential on the ionization equilibrium conditions for bound electron-hole pairs (excitons) in III--V semiconductor heterostructures. It is demonstrated that ionization equilibrium conditions for bound electron-hole pairs change drastically in the presence of strong disorder. It is predicted that strong disorder promotes dissociation of excitons in III--V semiconductor heterostructures. A theory of polariton (photon dressed by phonon) spontaneous emission in a III--V semiconductor doped with semiconductor quantum dots (QDs) or quantum wells (QWs) is developed. For the first time, superradiant and subradiant polariton spontaneous emission phenomena in a polariton-QD (QW) coupled system are predicted when the resonance energies of the two identical QDs (QWs) lie outside the polaritonic energy gap. It is also predicted that when the resonance energies of the two identical QDs (QWs) lie inside the polaritonic energy gap, spontaneous emission of polariton in the polariton

  11. Near real-time tracking of dynamic properties for standalone structural health monitoring systems

    NASA Astrophysics Data System (ADS)

    Rainieri, C.; Fabbrocino, G.; Cosenza, E.

    2011-11-01

    Automated modal parameter identification of civil engineering structures has been analyzed in a previous paper. An original algorithm, named LEONIDA, working in frequency domain, has been presented and a number of test cases have been discussed in order to point out advantages and drawbacks. It has been demonstrated that LEONIDA represents a promising and reliable tool, in particular for modal testing. Conversely, integration of such a procedure into a fully automated structural health monitoring (SHM) system has shown that it can be used as modal information engine, but length of record durations, amount of computational burden and response time lead to recognize that serious drawbacks and limitations exist for a class of applications, such as continuous monitoring of structures in seismically prone areas. In fact, a fast assessment of relevant structure health conditions in the early post-earthquake phase is becoming of interest in different European areas. In such a context, the statistical treatment of measured dynamic properties could be certainly useful, but it requires the collection of an extensive amount of local and global data in a short time. As a consequence, availability of reliable, robust and fairly fast data processing procedures for modal tracking is fundamental whenever really effective and useful SHM systems are adopted to support civil protection activities during seismic sequences. This applies mainly to strategic structures, whose health conditions must be rapidly assessed after any seismic event, in order to securely manage rescue operations. In the present paper, the main issues related to a fast, robust and reliable modal tracking for emergency management are outlined. Then, an automated modal tracking strategy for SHM applications in earthquake prone regions is described. It is based on the knowledge of the experimental mode shapes and a revised concept of spatial filtering. Results of sample applications of the proposed procedure refer

  12. Geometries and focal properties of two electron-lens systems useful in low-energy electron or ion scattering

    NASA Technical Reports Server (NTRS)

    Chutjian, A.

    1979-01-01

    Geometries and focal properties are given for two types of electron-lens system commonly needed in electron scattering. One is an electron gun that focuses electrons from a thermionic emitter onto a fixed point (target) over a wide range of final energies. The other is an electron analyzer system that focuses scattered electrons of variable energy onto a fixed position (e.g., the entrance plane of an analyzer) at fixed energy with a zero final beam angle. Analyzer-system focusing properties are given for superelastically, elastically, and inelastically scattered electrons. Computer calculations incorporating recent accurate tube-lens focal properties are used to compute lens voltages, locations and diameters of all pupils and windows, filling factors, and asymptotic rays throughout each lens system. Focus voltages as a function of electron energy and energy change are given, and limits of operation of each system discussed. Both lens systems have been in routine use for several years, and good agreement has been consistently found between calculated and operating lens voltages.

  13. Dynamics of the human head-neck system in the horizontal plane: joint properties with respect to a static torque.

    PubMed

    Tangorra, James L; Jones, Lynette A; Hunter, Ian W

    2003-05-01

    The vestibular system has often been studied by perturbing the position of the head. This study was conducted to identify the dynamic properties of the head-neck system in response to horizontal plane perturbations. A quasilinear approach was used to quantify the dynamics of the head-neck system at different levels of static torque. An operating point was established by applying a static torque to the head with a helmet-based perturber. The head-neck dynamics were then probed with a rich spectrum, stochastic, torque perturbation. Impulse response functions (IRFs) were estimated from correlation measures, and parametric models were fit to the IRFs. The results indicated that when the mean torque was held constant, the head-neck system behaved like a second-order, underdamped, passive system between 0.5 and 10.0 Hz. The system was not strictly linear, however. The properties of the system were sensitive to the static component of the torque. As the mean torque increased, the effective stiffness and damping progressively increased, and did so such that the system's damping ratio remained essentially constant. The findings of the study will assist in designing stimuli that are well tolerated by subjects and can induce head motions that span the performance capabilities of the vestibular system.

  14. Hydraulic properties of the Madison aquifer system in the western Rapid City area, South Dakota

    USGS Publications Warehouse

    Greene, Earl A.

    1993-01-01

    Available information on hydrogeology, data from borehole geophysical logs, and aquifer tests were used to determine the hydraulic properties of the Madison aquifer. From aquifer-test analysis, transmissivity and storage coefficient were determined for the Minnelusa and Madison aquifers, and vertical hydraulic conductivity (Kv') along with specific storage (Ss') for the Minnelusa confining bed. Borehole geophysical well logs were used to determine the thickness and location of the Minnelusa aquifer, the lower Minnelusa confining bed, and the Madison aquifer within the Madison Limestone. Porosity values determined from quantitative analysis of borehole geophysical well logs were used in analyzing the aquifer-test data. The average porosity at the two aquifer-test sites is about 10 percent in the Minnelusa aquifer, 5 percent in the lower Minnelusa confining bed, and 35 percent in the Madison aquifer. The first aquifer test, which was conducted at Rapid City production well #6, produced measured drawdown in the Minnelusa and Madison aquifers. Neuman and Witherspoon's method of determining the hydraulic properties of leaky two-aquifer systems was used to evaluate the aquifer-test data by assuming the fracture and solution-opening network is equivalent to a porous media. Analysis of the aquifer test for the Minnelusa aquifer yielded a transmissivity value of 12,000 feet squared per day and a storage coefficient of 3 x 10-3. The specific storage of the Minnelusa confining bed was 2 x 10-7 per foot, and its vertical hydraulic conductivity was 0.3 foot per day. The transmissivity of the Madison aquifer at this site was 17,000 feet squared per day, and the storage coefficient was 2 x 10-3. The second aquifer test, which was conducted at Rapid City production well #5 (RC-5) produced measured drawdown only in the Madison aquifer. Hantush and Jacob's method of determining the hydraulic properties of leaky confined aquifers with no storage in the confining bed was used to

  15. Naturalizing semiotics: The triadic sign of Charles Sanders Peirce as a systems property.

    PubMed

    Kilstrup, Mogens

    2015-12-01

    process in molecular biological systems. It became clear, however, that the model is able to clarify many of the difficult explanations offered by Peirce about his sign model. I make no claim that Peirce used a similar type of three-dimensional model, because he explicitly used the chemical atom as naturalization (natural scientific explanation) for his sign model, an interesting but problematic analogy. In order to discuss common versus specific semiotic scaffolds for molecular biosemiotics, biosemiotics and semiotics proper, I start with a generic definition of the three-dimensional sign system, using human semiosis as examples. After this, the major part of the paper, I define the specific biochemical and evolutionary scaffolds that is used for obtaining the evolutionary memory that is needed for sign establishment. To exemplify semiosis according to the present model I present a typical situation where a Representamen (RE) and an object (OE) in the establishment phase are frequently encountered together by a sign interpreter. The process that links specific Representamens to specific Objects will first involve the recognition of the specific traits that distinguish the two sign elements. Subsequently the establishment process leads to the creation of a specific systems-state, called the Interpretant, which links the two traits in a way that allows retrieval of the information (a memory function). During a later interpretation phase, a hypothetical Object will be inferred by the interpreter when a Representamen (RI) harboring the required characteristics is encountered. This inference happens through a memory retrieval process, irrespective of the fact that relevant Objects of the sign may never be encountered after establishment. A simplified scheme for computer neural network algorithms is introduced as an example of such a system. Since the Peircean sign according to this definition is a systems property, there can be no sign without a sign interpreting systems or

  16. The Geographic Information System techniques impact analyze of Office's Properties in Barcelona

    NASA Astrophysics Data System (ADS)

    Garcia, P. A.; Biere, R. A.; Moix, M. B.

    2007-05-01

    The changes in the characteristics and needs in the cities structures means new challenges in the space to the economics activities. The increasing predominance of the tertiary industry, of offices or I+D buildings, like an effect of the economic transformation implies new forms, new technical characteristics and similar alternatives locations accordant with a changing demand. The project that is presented here, is developed by the Centre of Land Policy and Valuations of the University Polytechnic of Catalonia for the company "Servicios de Geo-marketing Inmobiliario S.L.' (SGMI, Real State Geo- marketing Services S.L.) The process consists in the generation of a geographic information system to the analyses of the characteristics office's buildings of Barcelona in the sense to introduce the property office's buildings of Barcelona into a database for the geo-marketing. This application allows the access to the necessary information of technical and constructive characteristics of the office's buildings, summoned by the most emblematic or central locations to the best technical level in their constructions towards facilitating the maximum knowledge the citizen in order to assure the choice according to the needs for every profile of demand. The work has consisted basically in defining the technical criteria of evaluation of the building, to systematize those characteristics in some indicators (variable) capable of expressing the level of quality of every variable, to establish a system measurement of greater to smaller value explained to the quality. Systematizing the collection of information of a total of 683 buildings of Barcelona and of some municipalities of its periphery, through a visit to every building, to process the data obtained to a database and to standardize the value of quality for every indicator and set of indicators towards determining a final qualification, obtained from the different physical, constructive and qualitative characteristics of

  17. Orbital alignment and star-spot properties in the WASP-52 planetary system

    NASA Astrophysics Data System (ADS)

    Mancini, L.; Southworth, J.; Raia, G.; Tregloan-Reed, J.; Mollière, P.; Bozza, V.; Bretton, M.; Bruni, I.; Ciceri, S.; D'Ago, G.; Dominik, M.; Hinse, T. C.; Hundertmark, M.; Jørgensen, U. G.; Korhonen, H.; Rabus, M.; Rahvar, S.; Starkey, D.; Calchi Novati, S.; Figuera Jaimes, R.; Henning, Th.; Juncher, D.; Haugbølle, T.; Kains, N.; Popovas, A.; Schmidt, R. W.; Skottfelt, J.; Snodgrass, C.; Surdej, J.; Wertz, O.

    2017-02-01

    We report 13 high-precision light curves of eight transits of the exoplanet WASP-52 b, obtained by using four medium-class telescopes, through different filters, and adopting the defocussing technique. One transit was recorded simultaneously from two different observatories and another one from the same site but with two different instruments, including a multiband camera. Anomalies were clearly detected in five light curves and modelled as star-spots occulted by the planet during the transit events. We fitted the clean light curves with the JKTEBOP code, and those with the anomalies with the PRISM+GEMC codes in order to simultaneously model the photometric parameters of the transits and the position, size and contrast of each star-spot. We used these new light curves and some from the literature to revise the physical properties of the WASP-52 system. Star-spots with similar characteristics were detected in four transits over a period of 43 d. In the hypothesis that we are dealing with the same star-spot, periodically occulted by the transiting planet, we estimated the projected orbital obliquity of WASP-52 b to be λ = 3.8° ± 8.4°. We also determined the true orbital obliquity, ψ = 20° ± 50°, which is, although very uncertain, the first measurement of ψ purely from star-spot crossings. We finally assembled an optical transmission spectrum of the planet and searched for variations of its radius as a function of wavelength. Our analysis suggests a flat transmission spectrum within the experimental uncertainties.

  18. Observational Properties of Type Ib/c Supernova Progenitors in Binary Systems

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Jeong; Yoon, Sung-Chul; Koo, Bon-Chul

    2015-08-01

    In several recent observational studies of Type Ib/c supernovae (SNe Ib/c), the inferred ejecta masses have a peak value of 2.0-4.0 {M}⊙ , in favor of the binary scenario for their progenitors rather than the Wolf-Rayet star scenario. To investigate the observational properties of relatively low-mass helium stars in binary systems as possible SN Ib/c progenitors, we constructed atmospheric models with the non-LTE radiative transfer code CMFGEN, using binary star evolution models. We find that these helium stars can be characterized by relatively narrow helium emission lines if the mass-loss rate during the final evolutionary phase is significantly enhanced as implied by many SN Ib/c observations. The optical brightness of helium star progenitors can be meaningfully enhanced with a strong wind for stars with M≳ 4.4 {M}⊙ , but is hardly affected or slightly weakened for relatively low-mass stars with ˜ 3.0 {M}⊙ , compared to the simple estimate using blackbody approximation. We further confirm the previous suggestion that the optical brightness would be generally higher for a less massive SN Ib/c progenitor. In good agreement with previous studies, our results indicate that the optical magnitudes and colors of the recently detected progenitor of the SN Ib iPTF13bvn can be well explained by a binary progenitor with a final helium star mass of about 3.0-4.4 {M}⊙ .

  19. Properties of amorphous silica nanoparticles colloid drug delivery system synthesized using the micelle formation method

    NASA Astrophysics Data System (ADS)

    Ab Wab, Hajarul Azwana; Abdul Razak, Khairunisak; Zakaria, Nor Dyana

    2014-02-01

    This study describes the formation and properties of a silica nanocolloid drug delivery system synthesized using micelle formation method. Previously, we have reported feasibility of using the same approach to entrap colorless water soluble drug (isoniazid). However, the entrapment of the drug inside nanoparticles (NPs) could not be observed due to its colorless nature. In this study, poor water soluble Rifampicin (RIF) was used as a drug model. Orange color of RIF enables observation and measurement using UV-Vis spectrophotometer. Several parameters were systematically studied: reaction temperature (25-70 °C) produced 28-97 nm, amount of surfactant (4-9 g) produced 44-66 nm, butanol volume (6-18 ml) produced 50-157 nm, and drug concentration. Particle size could be tuned from 28 to 157 nm by varying synthesis parameters. NP size was highly influenced by reaction temperature and butanol. Silica nanocolloid-entrapped RIF (50 and 70 nm SiRif) were synthesized and further analyzed for biological application. The stability of SiRif in biological media, such as in 0.1, 0.5, and 1.0 M NaCl solution and 5, 10, and 25 % mouse serum, was examined. RIF was successfully entrapped inside silica nanocolloids. Moreover, 50 and 70 nm SiRif exhibited almost similar stability in NaCl and mouse serum. The drug release profiles in 0.1 and 1.0 mM phosphate buffer solutions and different pH at 37 °C were examined for several days. Results indicate that 70 nm SiRif had higher drug loading and slower release profile than 50 nm SiRif. 70 nm SiRif was optimally released at pH 6.8.

  20. Testing fungistatic properties of soil-like substrate for growing plants in bioregenerative life support systems

    NASA Astrophysics Data System (ADS)

    Enzhu, Hu; Nesterenko, Elena; Liu, Professor Hong; Manukovsky, N. S.; Kovalev, Vladimir; Gurevich, Yu.; Kozlov, Vladimir; Khizhnyak, Serge; Xing, Yidong; Hu, Enzhu; Enzhu, Hu

    There are two ways of getting vegetable food in BLSS: in hydroponic culture and on soil substrates. In any case there is a chance that the plants will be affected by plant pathogenic microorganisms. The subject of the research was a soil-like substrate (SLS) for growing plants in a Bioregenerative Life Support System (BLSS). We estimated the fungistatic properties of SLS using test cultures of Bipolaris and Alternaria plant pathogenic fungi. Experiments were made with the samples of SLS, natural soil and sand (as control). We tested 2 samples of SLS produced by way of bioconversion of wheat and rice straw. We measured the disease severity of wheat seedlings and the incidence of common root rot in natural (non-infectious) background and man-made (infectious) conditions. The severity of disease on the SLS was considerably smaller both in non-infectious and infectious background conditions (8 and 12%) than on the natural soil (18 and 32%) and sand. It was the soil-like substrate that had the minimal value among the variants being compared (20% in non-infectious and 40% in infectious background conditions). This index in respect of the soil was 55 and 78%, correspondingly, and in respect of the sand - 60%, regardless of the background. It was found that SLS significantly suppressed conidia germination of Bipolaris soroikiniana (p<0.001). In the presence of SLS germination of conidia decreased to 9.9 - 12.2% of the control value. No significant differences were found between SLS samples obtained from wheat and rice straw.

  1. Drug-induced modification of the system properties associated with spontaneous human electroencephalographic activity

    NASA Astrophysics Data System (ADS)

    Liley, David T.; Cadusch, Peter J.; Gray, Marcus; Nathan, Pradeep J.

    2003-11-01

    The benzodiazepine (BZ) class of minor tranquilizers are important modulators of the γ-amino butyric acid (GABAA)/BZ receptor complex that are well known to affect the spectral properties of spontaneous electroencephalographic activity. While it is experimentally well established that the BZs reduce total alpha band (8 13 Hz) power and increase total beta band (13 30 Hz) power, it is unclear what the physiological basis for this effect is. Based on a detailed theory of cortical electrorhythmogenesis it is conjectured that such an effect is explicable in terms of the modulation of GABAergic neurotransmission within locally connected populations of excitatory and inhibitory cortical neurons. Motivated by this theory, fixed order autoregressive moving average (ARMA) models were fitted to spontaneous eyes-closed electroencephalograms recorded from subjects before and approximately 2 h after the oral administration of a single 1 mg dose of the BZ alprazolam. Subsequent pole-zero analysis revealed that BZs significantly transform the dominant system pole such that its frequency and damping increase. Comparisons of ARMA derived power spectra with fast Fourier transform derived spectra indicate an enhanced ability to identify benzodiazepine induced electroencephalographic changes. This experimental result is in accord with the theoretical predictions implying that alprazolam enhances inhibition acting on inhibitory neurons more than inhibition acting on excitatory neurons. Further such a result is consistent with reported cortical neuronal distributions of the various GABAA receptor pharmacological subtypes. Therefore physiologically specified fixed order ARMA modeling is expected to become an important tool for the systematic investigation and modeling of a wide range of cortically acting compounds.

  2. Drug-induced modification of the system properties associated with spontaneous human electroencephalographic activity.

    PubMed

    Liley, David T J; Cadusch, Peter J; Gray, Marcus; Nathan, Pradeep J

    2003-11-01

    The benzodiazepine (BZ) class of minor tranquilizers are important modulators of the gamma-amino butyric acid (GABA(A))/BZ receptor complex that are well known to affect the spectral properties of spontaneous electroencephalographic activity. While it is experimentally well established that the BZs reduce total alpha band (8-13 Hz) power and increase total beta band (13-30 Hz) power, it is unclear what the physiological basis for this effect is. Based on a detailed theory of cortical electrorhythmogenesis it is conjectured that such an effect is explicable in terms of the modulation of GABAergic neurotransmission within locally connected populations of excitatory and inhibitory cortical neurons. Motivated by this theory, fixed order autoregressive moving average (ARMA) models were fitted to spontaneous eyes-closed electroencephalograms recorded from subjects before and approximately 2 h after the oral administration of a single 1 mg dose of the BZ alprazolam. Subsequent pole-zero analysis revealed that BZs significantly transform the dominant system pole such that its frequency and damping increase. Comparisons of ARMA derived power spectra with fast Fourier transform derived spectra indicate an enhanced ability to identify benzodiazepine induced electroencephalographic changes. This experimental result is in accord with the theoretical predictions implying that alprazolam enhances inhibition acting on inhibitory neurons more than inhibition acting on excitatory neurons. Further such a result is consistent with reported cortical neuronal distributions of the various GABA(A) receptor pharmacological subtypes. Therefore physiologically specified fixed order ARMA modeling is expected to become an important tool for the systematic investigation and modeling of a wide range of cortically acting compounds.

  3. Chemical and kinematical properties of galactic bulge stars surrounding the stellar system Terzan 5

    SciTech Connect

    Massari, D.; Mucciarelli, A.; Ferraro, F. R.; Lanzoni, B.; Dalessandro, E.; Lovisi, L.; Rich, R. M.; Reitzel, D.; Ibata, R.

    2014-08-20

    As part of a study aimed at determining the kinematical and chemical properties of Terzan 5, we present the first characterization of the bulge stars surrounding this puzzling stellar system. We observed 615 targets located well beyond the tidal radius of Terzan 5 and found that their radial velocity distribution is well described by a Gaussian function peaked at (v {sub rad}) = +21.0 ± 4.6 km s{sup –1} with dispersion σ {sub v} = 113.0 ± 2.7 km s{sup –1}. This is one of the few high-precision spectroscopic surveys of radial velocities for a large sample of bulge stars in such a low and positive latitude environment (b = +1.°7). We found no evidence of the peak at (v {sub rad}) ∼ +200 km s{sup –1} found in Nidever et al. Strong contamination of many observed spectra by TiO bands prevented us from deriving the iron abundance for the entire spectroscopic sample, introducing a selection bias. The metallicity distribution was finally derived for a subsample of 112 stars in a magnitude range where the effect of the selection bias is negligible. The distribution is quite broad and roughly peaked at solar metallicity ([Fe/H] ≅ +0.05 dex) with a similar number of stars in the super-solar and in the sub-solar ranges. The population number ratios in different metallicity ranges agree well with those observed in other low-latitude bulge fields, suggesting (1) the possible presence of a plateau for |b| < 4° in the ratio between stars in the super-solar (0 < [Fe/H] <0.5 dex) and sub-solar (–0.5 < [Fe/H] <0 dex) metallicity ranges; (2) a severe drop in the metal-poor component ([Fe/H] <–0.5) as a function of Galactic latitude.

  4. Novel multiphase systems based on thermoplastic chitosan: Analysis of the structure-properties relationships

    NASA Astrophysics Data System (ADS)

    Avérous, Luc; Pollet, Eric

    2016-03-01

    In the last years, biopolymers have attracted great attention. It is for instance the case of chitosan, a linear polysaccharide. It is a deacetylated derivative of chitin, which is the second most abundant polysaccharide found in nature after cellulose. Chitosan has been found to be nontoxic, biodegradable, biofunctional, and biocompatible in addition to having antimicrobial and antifungal properties, and thus has a great potential for environmental (packaging,) or biomedical applications.For preparing chitosan-based materials, only solution casting or similar methods have been used in all the past studies. Solution casting have the disadvantage in low efficiency and difficulty in scaling-up towards industrial applications. Besides, a great amount of environmentally unfriendly chemical solvents are used and released to the environment in this method. The reason for not using a melt processing method like extrusion or kneading in the past studies is that chitosan, like many other polysaccharides such as starch, has very low thermal stability and degrade prior to melting. Therefore, even if the melt processing method is more convenient and highly preferred for industrial production, its adaptation for polysaccharide-based materials remains very difficult. However, our recently published studies has demonstrated the successful use of an innovative melt processing method (internal mixer, extrusion,) as an alternative route to solution casting, for preparing materials based on thermoplastic chitosan. These promising thermoplastic materials, obtained by melt processing, have been the main topic of recent international projects, with partners from different countries Multiphase systems based on various renewable plasticizers have been elaborated and studied. Besides, different blends, and nano-biocomposites based on nanoclays, have been elaborated and fully analyzed. The initial consortium of this vast project was based on an international consortium (Canada, Australia

  5. Detecting tissue optical and mechanical properties with an ultrasound modulated optical imaging system in reflection detection geometry

    PubMed Central

    Cheng, Yi; Li, Sinan; Eckersley, Robert J.; Elson, Daniel S.; Tang, Meng-Xing

    2014-01-01

    Tissue optical and mechanical properties are correlated to tissue pathologic changes. This manuscript describes a dual-mode ultrasound modulated optical imaging system capable of sensing local optical and mechanical properties in reflection geometry. The optical characterisation was achieved by the acoustic radiation force assisted ultrasound modulated optical tomography (ARF-UOT) with laser speckle contrast detection. Shear waves generated by the ARF were also tracked optically by the same system and the shear wave speed was used for the elasticity measurement. Tissue mimicking phantoms with multiple inclusions buried at 11 mm depth were experimentally scanned with the dual-mode system. The inclusions, with higher optical absorption and/or higher stiffness than background, were identified based on the dual results and their stiffnesses were quantified. The system characterises both optical and mechanical properties of the inclusions compared with the ARF-UOT or the elasticity measurement alone. Moreover, by detecting the backward scattered light in reflection detection geometry, the system is more suitable for clinical applications compared with transmission geometry. PMID:25657875

  6. Test system for evaluating the influence of polymer properties on primary human keratinocytes and fibroblasts in mono- and coculture.

    PubMed

    Trescher, Karoline; Roch, Toralf; Cui, Jing; Kratz, Karl; Lendlein, Andreas; Jung, Friedrich

    2013-06-20

    Interactions of cells with polymer-based biomaterials are influenced by properties of the substrate. Polymers, which are able to induce cell specific effects, gain increasing importance for biotechnology and regenerative therapies. A test system was developed, which allows studying primary human keratinocytes and fibroblasts in mono- and cocultures to analyze and operate the effect of polymer properties. This system offers to identify polymers for keratinocyte cultivation or wound dressings, since adherence, viability and functionality can be analyzed. Especially the coculture system enables the characterization of potential cell specific effects of polymer-based biomaterials. To establish a coculture test system, it is challenging to find a suitable culture medium, to identify initial seeding densities for comparable cell growth and to develop methods to distinguish and characterize both cell types. Poly(n-butyl acrylate) networks (cPnBAs) as model biomaterials were used to demonstrate the applicability of our newly developed coculture screening system for differential cell growth. The apparent Young's modulus of the cPnBAs differentially regulated fibroblasts and keratinocytes. Particularly, cPnBA73 with an apparent Young's modulus of 930±140 kPa measured in phosphate buffered saline (PBS) solution at ambient temperature seemed to have favoring properties for keratinocyte adhesion, while fibroblast adhesion was not affected. For keratinocytes the concentration of some pro-inflammatory cytokines was lower on cPnBA73 and a decreased deposition of collagen, elastin and fibronectin was observed in the coculture.

  7. Systematic ab initio study of the electronic and magnetic properties of different pure and mixed iron systems

    SciTech Connect

    Izquierdo, J.; Vega, A.; Balbas, L. C.; Sanchez-Portal, Daniel; Junquera, Javier; Artacho, Emilio; Soler, Jose M.; Ordejon, Pablo

    2000-05-15

    We present a theoretical study of the electronic and magnetic properties of iron systems in different environments: pure iron systems [dimer, bcc bulk, (100) surface, and free-standing iron monolayer], and low-dimensional iron systems deposited on Ag (100) surface (monoatomic linear wires, iron monolayer, planar, and three-dimensional clusters). Electronic and magnetic properties have been calculated using a recently developed total-energy first-principles method based on density-functional theory with numerical atomic orbitals as a basis set for the description of valence electrons and nonlocal pseudopotentials for the atomic core. The Kohn-Sham equations are solved self-consistently within the generalized gradient approximation for the exchange-correlation potential. Tests on the pseudopotential, the basis set, grid spacing, and k sampling are carefully performed. This technique, which has been proved to be very efficient for large nonmagnetic systems, is applied in this paper to calculate electronic and magnetic properties of different iron nanostructures. The results compare well with previous ab initio all-electron calculations and with experimental data. The method predicts the correct trends in the magnetic moments of Fe systems for a great variety of environments and requires a smaller computational effort than other ab initio methods. (c) 2000 The American Physical Society.

  8. Preparation of nanoporous systems for the study of the mechanical properties of silica aerogels by Molecular Dynamics simulations

    NASA Astrophysics Data System (ADS)

    Rivas Murillo, John S.; Bachlechner, Martina E.; Barbero, Ever J.

    2009-03-01

    This presentation focuses on the application of the Molecular Dynamics technique to study the mechanical properties of silica aerogels through the simulation of a tension test. It covers multiple areas, including aspects related to the preparation of a well-relaxed nanoporous system from the expansion of an amorphous bulk sample and the influence of the initial configuration of the system on the final results of the simulated tension test. The results presented here will help to develop a more complete procedure to prepare a proper sample for the study of the mechanical properties of a nanoporous system by using Molecular Dynamics. Comparison of the simulation results and previously published experimental data is provided

  9. The connection between typological complexes of properties of the nervous system, temperaments, and personality types in the professions and sports.

    PubMed

    Drozdovski, Aleksandr K

    2015-01-01

    Based on experimental studies in education, professions and sports, an attempt was made to combine the following two historically disconnected research directions in the study of the natural human traits into a single coordinate system: Pavlov's theory on the properties of the nervous system, as well as the types of higher nervous activity, and Jung's theory on psychological types. It is noted that Pavlov's school of thought was developed by his followers in Russia within the scientific school of differential psychophysiology, while Yung's theory was developed through the works of well-known American researchers Myers and Keirsey. The spatial model that is presented here rests on the knowledge of the properties of the human nervous system and enables the prediction of psychological characteristics, temperament, and psychological types of individuals belonging to a wide age range.

  10. Optical and electrical properties of stainless steel oxynitride thin films deposited in an in-line sputtering system

    NASA Astrophysics Data System (ADS)

    Carretero, E.; Alonso, R.; Pelayo, C.

    2016-08-01

    The optical and electrical properties of stainless steel oxynitride thin films have been studied for different flow rates of the reactive gases during the deposition process. Films were deposited in an in-line magnetron sputtering system under similar conditions as those found in large area industrial systems. The study of the optical properties was performed by IR-VIS spectrophotometry, DC conductivity measurements were performed by the four point method and the microstructural study and chemical analysis were performed by XRD, FESEM and XPS. The results show the transition of sample films from metal to semiconductor, as well as the feasibility of obtaining visible absorbing coatings with low DC conductivity from low-cost materials. The deposited films show the typical growth structure for samples produced in in-line deposition systems commonly used in the large area coatings industry.

  11. The connection between typological complexes of properties of the nervous system, temperaments, and personality types in the professions and sports

    PubMed Central

    Drozdovski, Aleksandr K

    2015-01-01

    Based on experimental studies in education, professions and sports, an attempt was made to combine the following two historically disconnected research directions in the study of the natural human traits into a single coordinate system: Pavlov’s theory on the properties of the nervous system, as well as the types of higher nervous activity, and Jung’s theory on psychological types. It is noted that Pavlov’s school of thought was developed by his followers in Russia within the scientific school of differential psychophysiology, while Yung’s theory was developed through the works of well-known American researchers Myers and Keirsey. The spatial model that is presented here rests on the knowledge of the properties of the human nervous system and enables the prediction of psychological characteristics, temperament, and psychological types of individuals belonging to a wide age range. PMID:26056499

  12. Fracture Toughness, Mechanical Property, And Chemical Characterization Of A Critical Modification To The NASA SLS Solid Booster Internal Material System

    NASA Technical Reports Server (NTRS)

    Pancoast, Justin; Garrett, William; Moe, Gulia

    2015-01-01

    A modified propellant-liner-insulation (PLI) bondline in the Space Launch System (SLS) solid rocket booster required characterization for flight certification. The chemical changes to the PLI bondline and the required additional processing have been correlated to mechanical responses of the materials across the bondline. Mechanical properties testing and analyses included fracture toughness, tensile, and shear tests. Chemical properties testing and analyses included Fourier transform infrared (FTIR) spectroscopy, cross-link density, high-performance liquid chromatography (HPLC), gas chromatography (GC), gel permeation chromatography (GPC), and wave dispersion X-ray fluorescence (WDXRF). The testing identified the presence of the expected new materials and found the functional bondline performance of the new PLI system was not significantly changed from the old system.

  13. Procedure for implementation of temperature-dependent mechanical property capability in the Engineering Analysis Language (EAL) system

    NASA Technical Reports Server (NTRS)

    Glass, David E.; Robinson, James C.

    1990-01-01

    A procedure is presented to allow the use of temperature dependent mechanical properties in the Engineering Analysis Language (EAL) System for solid structural elements. This is accomplished by including a modular runstream in the main EAL runstream. The procedure is applicable for models with multiple materials and with anisotropic properties, and can easily be incorporated into an existing EAL runstream. The procedure (which is applicable for EAL elastic solid elements) is described in detail, followed by a description of the validation of the routine. A listing of the EAL runstream used to validate the procedure is included in the Appendix.

  14. Paraxial properties of three-element zoom system for laser beam expanders based on tunable-focus lenses.

    PubMed

    Mikš, Antonín; Novák, Pavel

    2015-06-15

    The paper is focused on the problem of a theoretical analysis of paraxial imaging properties and initial optical design of the three-element zoom optical system for laser beam expanders using lenses with a tunable focal length. Equations which allow calculation of required optical powers of individual elements of the three-element zoom optical system for laser beam expander depending on the value of the axial position of the beam waist of the input Gaussian beam and the required magnification of the system are derived.

  15. Can percolation model describe the evolution of mechanical properties of compacts of binary systems?

    NASA Astrophysics Data System (ADS)

    Evesque, Pierre; Busignies, Virginie; Porion, Patrice; Leclerc, Bernard; Tchoreloff, Pierre

    2009-06-01

    In pharmaceutical field, the percolation theory is used to describe the change of tablet's properties with the relative density. It defines critical tablet densities from which the mechanical properties start to change. The exponent in the law is expected to be universal for a mechanical property and numerical values are proposed in the literature. In this work, the percolation model was applied to the tensile strength and the reduced modulus of elasticity of three compacted pharmaceutical excipients. This work showed that the exponent seems not universal and that the model must be used carefully.

  16. On classes of integrable systems and the Painlevé property

    NASA Astrophysics Data System (ADS)

    Weiss, John

    1984-01-01

    The Caudrey-Dodd-Gibbon equation is found to possess the Painlevé property. Investigation of the Bäcklund transformations for this equation obtains the Kuperschmidt equation. A certain transformation between the Kuperschmidt and Caudrey-Dodd-Gibbon equation is obtained. This transformation is employed to define a class of p.d.e.'s that identically possesses the Painlevé property. For equations within this class Bäcklund transformations and rational solutions are investigated. In particular, the sequences of higher order KdV, Caudrey-Dobb-Gibbon, and Kuperschmidt equations are shown to possess the Painlevé property.

  17. FORTRAN 4 computer program for calculation of thermodynamic and transport properties of complex chemical systems

    NASA Technical Reports Server (NTRS)

    Svehla, R. A.; Mcbride, B. J.

    1973-01-01

    A FORTRAN IV computer program for the calculation of the thermodynamic and transport properties of complex mixtures is described. The program has the capability of performing calculations such as:(1) chemical equilibrium for assigned thermodynamic states, (2) theoretical rocket performance for both equilibrium and frozen compositions during expansion, (3) incident and reflected shock properties, and (4) Chapman-Jouguet detonation properties. Condensed species, as well as gaseous species, are considered in the thermodynamic calculation; but only the gaseous species are considered in the transport calculations.

  18. Soil Microbial Substrate Properties and Microbial Community Responses under Irrigated Organic and Reduced-Tillage Crop and Forage Production Systems

    PubMed Central

    Ghimire, Rajan; Norton, Jay B.; Stahl, Peter D.; Norton, Urszula

    2014-01-01

    Changes in soil microbiotic properties such as microbial biomass and community structure in response to alternative management systems are driven by microbial substrate quality and substrate utilization. We evaluated irrigated crop and forage production in two separate four-year experiments for differences in microbial substrate quality, microbial biomass and community structure, and microbial substrate utilization under conventional, organic, and reduced-tillage management systems. The six different management systems were imposed on fields previously under long-term, intensively tilled maize production. Soils under crop and forage production responded to conversion from monocropping to crop rotation, as well as to the three different management systems, but in different ways. Under crop production, four years of organic management resulted in the highest soil organic C (SOC) and microbial biomass concentrations, while under forage production, reduced-tillage management most effectively increased SOC and microbial biomass. There were significant increases in relative abundance of bacteria, fungi, and protozoa, with two- to 36-fold increases in biomarker phospholipid fatty acids (PLFAs). Under crop production, dissolved organic C (DOC) content was higher under organic management than under reduced-tillage and conventional management. Perennial legume crops and organic soil amendments in the organic crop rotation system apparently favored greater soil microbial substrate availability, as well as more microbial biomass compared with other management systems that had fewer legume crops in rotation and synthetic fertilizer applications. Among the forage production management systems with equivalent crop rotations, reduced-tillage management had higher microbial substrate availability and greater microbial biomass than other management systems. Combined crop rotation, tillage management, soil amendments, and legume crops in rotations considerably influenced soil

  19. Soil microbial substrate properties and microbial community responses under irrigated organic and reduced-tillage crop and forage production systems.

    PubMed

    Ghimire, Rajan; Norton, Jay B; Stahl, Peter D; Norton, Urszula

    2014-01-01

    Changes in soil microbiotic properties such as microbial biomass and community structure in response to alternative management systems are driven by microbial substrate quality and substrate utilization. We evaluated irrigated crop and forage production in two separate four-year experiments for differences in microbial substrate quality, microbial biomass and community structure, and microbial substrate utilization under conventional, organic, and reduced-tillage management systems. The six different management systems were imposed on fields previously under long-term, intensively tilled maize production. Soils under crop and forage production responded to conversion from monocropping to crop rotation, as well as to the three different management systems, but in different ways. Under crop production, four years of organic management resulted in the highest soil organic C (SOC) and microbial biomass concentrations, while under forage production, reduced-tillage management most effectively increased SOC and microbial biomass. There were significant increases in relative abundance of bacteria, fungi, and protozoa, with two- to 36-fold increases in biomarker phospholipid fatty acids (PLFAs). Under crop production, dissolved organic C (DOC) content was higher under organic management than under reduced-tillage and conventional management. Perennial legume crops and organic soil amendments in the organic crop rotation system apparently favored greater soil microbial substrate availability, as well as more microbial biomass compared with other management systems that had fewer legume crops in rotation and synthetic fertilizer applications. Among the forage production management systems with equivalent crop rotations, reduced-tillage management had higher microbial substrate availability and greater microbial biomass than other management systems. Combined crop rotation, tillage management, soil amendments, and legume crops in rotations considerably influenced soil

  20. Soil biochemical properties and microbial resilience in agroforestry systems: effects on wheat growth under controlled drought and flooding conditions.

    PubMed

    Rivest, David; Lorente, Miren; Olivier, Alain; Messier, Christian

    2013-10-01

    Agroforestry is increasingly viewed as an effective means of maintaining or even increasing crop and tree productivity under climate change while promoting other ecosystem functions and services. This study focused on soil biochemical properties and resilience following disturbance within agroforestry and conventional agricultural systems and aimed to determine whether soil differences in terms of these biochemical properties and resilience would subsequently affect crop productivity under extreme soil water conditions. Two research sites that had been established on agricultural land were selected for this study. The first site included an 18-year-old windbreak, while the second site consisted in an 8-year-old tree-based intercropping system. In each site, soil samples were used for the determination of soil nutrient availability, microbial dynamics and microbial resilience to different wetting-drying perturbations and for a greenhouse pot experiment with wheat. Drying and flooding were selected as water stress treatments and compared to a control. These treatments were initiated at the beginning of the wheat anthesis period and maintained over 10 days. Trees contributed to increase soil nutrient pools, as evidenced by the higher extractable-P (both sites), and the higher total N and mineralizable N (tree-based intercropping site) found in the agroforestry compared to the conventional agricultural system. Metabolic quotient (qCO2) was lower in the agroforestry than in the conventional agricultural system, suggesting higher microbial substrate use efficiency in agroforestry systems. Microbial resilience was higher in the agroforestry soils compared to soils from the conventional agricultural system (windbreak site only). At the windbreak site, wheat growing in soils from agroforestry system exhibited higher aboveground biomass and number of grains per spike than in conventional agricultural system soils in the three water stress treatments. At the tree

  1. A quantitative risk-based model for reasoning over critical system properties

    NASA Technical Reports Server (NTRS)

    Feather, M. S.

    2002-01-01

    This position paper suggests the use of a quantitative risk-based model to help support reeasoning and decision making that spans many of the critical properties such as security, safety, survivability, fault tolerance, and real-time.

  2. JV Task 117 - Impact of Lignite Properties on Powerspan's NOx Oxidation System

    SciTech Connect

    Scott Tolbert; Steven Benson

    2008-02-29

    Powerspan's multipollutant control process called electrocatalytic oxidation (ECO) technology is designed to simultaneously remove SO{sub 2}, NO{sub x}, PM{sub 2.5}, acid gases (such as hydrogen fluoride [HF], hydrochloric acid [HCl], and sulfur trioxide [SO{sub 3}]), Hg, and other metals from the flue gas of coal-fired power plants. The core of this technology is a dielectric barrier discharge reactor composed of cylindrical quartz electrodes residing in metal tubes. Electrical discharge through the flue gas, passing between the electrode and the tube, produces reactive O and OH radicals. The O and OH radicals react with flue gas components to oxidize NO to NO{sub 2} and HNO{sub 3} and a small portion of the SO{sub 2} to SO{sub 3} and H{sub 2}SO{sub 4}. The oxidized compounds are subsequently removed in a downstream scrubber and wet electrostatic precipitator. A challenging characteristic of selected North Dakota lignites is their high sodium content. During high-sodium lignite combustion and gas cooling, the sodium vaporizes and condenses to produce sodium- and sulfur-rich aerosols. Based on past work, it was hypothesized that the sodium aerosols would deposit on and react with the silica electrodes and react with the silica electrodes, resulting in the formation of sodium silicate. The deposit and reacted surface layer would then electrically alter the electrode, thus impacting its dielectric properties and NO{sub x} conversion capability. The purpose of this project was to determine the impact of lignite-derived flue gas containing sodium aerosols on Powerspan's dielectric barrier discharge (DBD) reactor with specific focus on the interaction with the quartz electrodes. Partners in the project were Minnkota Power Cooperative; Basin Electric Power Cooperative; Montana Dakota Utilities Co.; Minnesota Power; the North Dakota Industrial Commission, the Lignite Energy Council, and the Lignite Research Council; the Energy & Environmental Research Center (EERC); and

  3. Microstructure-property correlations in the Bi(Pb)-Sr-Ca-Cu-O superconducting system

    SciTech Connect

    Ramesh, R.; Green, S. M.; Mei, Y.; Manzi, A. E.; Luo, H. L.

    1989-08-01

    The microstructure of solid-state processed (Bi,Pb)-Sr-Ca-Cu-O ceramics was characterized using transmission electron microscopy techniques. A strong sensitivity of the transport properties to small deviations in the nominal Bi-Ca ratio is evidenced. Significant differences in the microstructure are shown to correlate to the changes in the transport properties. It is suggested that the microstructure can be predicted by combining the results of resistivity, Meissner, and shielding experiments.

  4. Probing volumetric properties of biomolecular systems by pressure perturbation calorimetry (PPC)--the effects of hydration, cosolvents and crowding.

    PubMed

    Suladze, Saba; Kahse, Marie; Erwin, Nelli; Tomazic, Daniel; Winter, Roland

    2015-04-01

    Pressure perturbation calorimetry (PPC) is an efficient technique to study the volumetric properties of biomolecules in solution. In PPC, the coefficient of thermal expansion of the partial volume of the biomolecule is deduced from the heat consumed or produced after small isothermal pressure-jumps. The expansion coefficient strongly depends on the interaction of the biomolecule with the solvent or cosolvent as well as on its packing and internal dynamic properties. This technique, complemented with molecular acoustics and densimetry, provides valuable insights into the basic thermodynamic properties of solvation and volume effects accompanying interactions, reactions and phase transitions of biomolecular systems. After outlining the principles of the technique, we present representative examples on protein folding, including effects of cosolvents and crowding, together with a discussion of the interpretation, and further applications.

  5. External insulation systems for cryogenic storage systems. Volume 1: Optical properties of Kapton and report of process variable study

    NASA Technical Reports Server (NTRS)

    Frank, A. M.

    1974-01-01

    Investigations are conducted into the optical properties of the glass and Kapton substrate materials, and three variables were chosen: deposition rate, sputter gas pressure, and film contamination time. Substrate tests have shown that fabrication of an dielectric broadband reflector would require an extremely complex and expensive filter design.

  6. Estimated hydraulic properties for the surficial-and bedrock-aquifer system, Meddybemps, Maine

    USGS Publications Warehouse

    Lyford, Forest P.; Garabedian, Stephen P.; Hansen, Bruce P.

    1999-01-01

    Analytical and numerical-modeling methods were used to estimate hydraulic properties of the aquifer system underlying the Eastern Surplus Company Superfund Site in Meddybemps, Maine. Estimates of hydraulic properties are needed to evaluate pathways for contaminants in ground water and to support evaluation and selection of remediation measures for contaminated ground water at this site. The hydraulic conductivity of surficial materials, determined from specific-capacity tests, ranges from 17 to 78 feet per day for wells completed in coarse-grained glaciomarine sediments, and from about 0.1 to 1.Ofoot per day for wells completed in till. The transmissivity of fractured bedrock determined from specific-capacity tests and aquifer tests in wells completed in less than 200 feet of bedrock ranges from about 0.09 to 130 feet squared per day. Relatively high values of transmissivity at the south end of the study area appear to be associated with a high-angle fracture or fracture zone that hydraulically connects two wells completed in bedrock. Transmissivities at six low-yielding (less than 0.5 gallon per minute) wells, which appear to lie within a poorly transmissive block of the bedrock, are consistently in a range of about 0.09 to 0.5 foot squared per day. The estimates of hydraulic conductivity and transmissivity in the southern half of the study area are supported by results of steady-state calibration of a numerical model and simulation of a 24-hour pumping test at a well completed in bedrock. Hydraulic conductivity values for the surficial aquifer used in the model were 30 feet per day for coarse-grained glaciomarine sediments, 0.001 to 0.01 foot per day for fine-grained glaciomarine sediments, and 0.1 to 0.5 foot per day for till. As part of model calibration, a relatively transmissive zone in the surficial aquifer was extended beyond the hypothesized extent of coarse-grained sediments eastward to the Dennys River. Hydraulic conductivity values used for bedrock in

  7. Interfacial Properties of a Hydrophobic Dye in the Tetrachloroethylene-Water-Glass Systems

    SciTech Connect

    Tuck, D.M.

    1999-02-23

    Interfacial effects play an important role in governing multiphase fluid behavior in porous media. Strongly hydrophobic organic dyes, used in many experimental studies to facilitate visual observation of the phase distributions, have generally been implicitly assumed to have no influence on the interfacial properties of the various phases in porous media. Sudan IV is the most commonly used dye for non-aqueous phase liquids (NAPLs) in laboratory experiments. It has also been used in at least one field experiment. The effects of this dye on the tetrachloroethylene (PCE)-water-glass system were investigated to test the assumption that the dye does not effect the interfacial properties and therefore PCE mobility. The results indicate that the dye does indeed change the interfacial relationships.The effect of the dye on the interfacial relationships is a complex function of the dye concentration, the solid phase composition, and the dynamic rate of new interface formation. The dye caused a slight (<10 percent) increase in interfacial tension at low concentrations (<0.1 g/L) and high rates of new interface formation. The dye reduced interfacial tension between PCE and water at low rates of new interface formation for all dye concentrations tested (0.00508 to 5.08 g/L). At the highest dye concentration, the PCE-water interfacial tension was significantly reduced regardless of the rate of new interface formation. The apparent interfacial tension increase at low dye concentrations is suspected to be an artifact of a low measured IFT value for the undyed PCE caused by leaching of rubber o-rings by the PCE prior to testing in the final drop-volume configuration.In addition to reducing interfacial tension, the dye was found to significantly alter the wetting relationship between PCE and water on a glass surface at and above the range of reported dye concentrations cited in the literature (1.1 to 1.7 g/L). The wetting relationship was rendered neutral from a water-wet initial

  8. a Molecular Approach to Electrolyte Solutions: Predicting Phase Behavior and Thermodynamic Properties of Single and Binary-Solvent Systems

    NASA Astrophysics Data System (ADS)

    Gering, Kevin Leslie

    A molecular formulation based on modern liquid state theory is applied to the properties and phase behavior of electrolyte systems containing volatile species. An electrolyte model based on the exponential modification of the Mean Spherical Approximation (EXP-MSA) is used to describe the cation-cation, cation-anion, and anion-anion distributions of the ionic species. This theory represents an improvement over the nonmodified MSA approach, and goes beyond the usual Debye-Huckel theory and Pitzer correlation for treating concentrated solutions. Electrolyte solutions such as water-salt, ammonia-salt, mixed salts, and mixed -solvent systems are investigated over a wide range of temperatures, pressures, and compositions. The usual salt properties, such as osmotic and mean activity coefficients and other thermodynamic properties (enthalpies), are calculated. The predictions are accurate to saturation limits. In addition, an iterative method is presented that is used to predict vapor-liquid equilibria (VLE) and thermodynamic properties of single-salt multisolvent electrolytes of the form solvent-cosolvent-salt. In this method, a local composition model (LCM) and EXP-MSA theory are combined with traditional phase equilibria relations to estimate the pressures and compositions of a vapor phase in equilibrium with a binary-solvent electrolyte. Also, a pseudo-solvent model is proposed as a means of obtaining a variety of averaged liquid phase electrolyte properties. To predict preferential solvation in mixed solvents, a general framework is developed that is based on predicted solvation numbers of each solvent. Preferential solvation will be shown to influence VLE. Results show that phase equilibria is accurately predicted by the above iterative method. Three mixed-solvent electrolyte systems are investigated: water -ethylene glycol-LiBr, ammonia-water-LiBr, and methanol -water-LiCl. Finally, the above electrolyte model is utilized in predicting design criteria for a single

  9. Mammalian photoperiodic system: formal properties and neuroendocrine mechanisms of photoperiodic time measurement.

    PubMed

    Goldman, B D

    2001-08-01

    Photoperiodism is a process whereby organisms are able to use both absolute measures of day length and the direction of day length change as a basis for regulating seasonal changes in physiology and behavior. The use of day length cues allows organisms to essentially track time-of-year and to "anticipate" relatively predictable annual variations in important environmental parameters. Thus, adaptive types of seasonal biological changes can be molded through evolution to fit annual environmental cycles. Studies of the formal properties of photoperiodic mechanisms have revealed that most organisms use circadian oscillators to measure day length. Two types of paradigms, designated as the external and internal coincidence models, have been proposed to account for photoperiodic time measurement by a circadian mechanism. Both models postulate that the timing of light exposure, rather than the total amount of light, is critical to the organism's perception of day length. In mammals, a circadian oscillator(s) in the suprachiasmatic nucleus of the hypothalamus receives photic stimuli via the retinohypothalamic tract. The circadian system regulates the rhythmic secretion of the pineal hormone, melatonin. Melatonin is secreted at night, and the duration of secretion varies in inverse relation to day length; thus, photoperiod information is "encoded" in the melatonin signal. The melatonin signal is presumably "decoded" in melatonin target tissues that are involved in the regulation of a variety of seasonal responses. Variations in photoperiodic response are seen not only between species but also between breeding populations within a species and between individuals within single breeding populations. Sometimes these variations appear to be the result of differences in responsiveness to melatonin; in other cases, variations in photoperiod responsiveness may depend on differences in patterns of melatonin secretion related to circadian variation. Sites of action for melatonin in

  10. Alongcoast structure and interannual variability of seasonal midshelf water properties and velocity in the Northern California Current System

    NASA Astrophysics Data System (ADS)

    Hickey, B.; Geier, S.; Kachel, N.; Ramp, S.; Kosro, P. M.; Connolly, T.

    2016-10-01

    Moored sensors were maintained for ˜5 years on the northern California Current System (CCS) midshelf. The alongcoast sensor array spanned the area of influence of the plume from the Columbia River, several submarine canyons, as well as a coastal promontory where the equatorward coastal jet frequently separates from the shelf. Upwelling-favorable wind stress magnitude decreases poleward by more than a factor of three over the latitudinal range and shelf width varies by a factor of two. In spite of the alongcoast structure in setting, both seasonal and interannual patterns in subsurface layer water properties were remarkably similar at all sites. Higher in the water column, freshwater forcing was substantial. Because of the near surface freshwater input, seasonal sea surface and subsurface temperatures were almost perfectly out of phase in the northernmost CCS, with a mid water column inversion in winter. Year to year differences in subsurface layer wintertime water properties were similar to spatial and temporal patterns of wind stress variability: little alongcoast structure except in salinity, but pronounced interannual differences strongly related to local wind stress. Summertime wind and subsurface property patterns were the opposite of those in winter: pronounced alongcoast wind stress structure, but little or no alongcoast or interannual variability in water properties, and only a weak relationship to local wind stress. Summertime interannual water property variability, including source waters, was shown to be more consistent with "remote forcing" via larger scale wind stress rather than with local wind stress, particularly in the northernmost CCS.

  11. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Effect of Co-Substitution on Magnetic Properties in Spinels GeNi2O4 Systems

    NASA Astrophysics Data System (ADS)

    Masrourl, R.; Hamedoun, M.; Benyoussef, A.; Hourmatallah, A.; Bouslykhane, K.; Benzakour, N.

    2008-11-01

    The magnetic properties of spinel GeNi2-2xCo2xO4 systems in the range 0 <= x <= 1 are studied by mean Geld theory and high-temperature series expansions. The nearest neighbouring and the next-neighbouring super-exchange interactions J1(x) and J2(x) are evaluated for these systems in the range 0 <= x <= 1, by using the first theory. The intra-planar and the inter-planar interactions and the exchange energy are deduced. The second theory is applied in the spinel GeNi2-2xCo2xO4 systems, combined with the Padé approximants method, to determine the magnetic phase diagrams (Tn versus dilution x) in the range 0 <= x <= 1. The obtained theoretical results are in agreement with experimental data obtained by magnetic measurements. The critical exponents associated with the magnetic susceptibility γ and the correlation lengths v are deduced.

  12. Structure-property relationships in multilayered polymeric system and olefinic block copolymers

    NASA Astrophysics Data System (ADS)

    Khariwala, Devang

    Chapter 1. The effect of tie-layer thickness on delamination behavior of polypropylene/tie-layer/Nylon-6 multilayers is examined in this study. Various maleated polypropylene resins were compared for their effectiveness as tie-layers. Delamination failure occurred cohesively in all the multilayer systems. Two adhesion regimes were defined based on the change in slope of the linear relationship between the delamination toughness and the tie-layer thickness. The measured delamination toughness of the various tie-layers was quantitatively correlated to the damage zone length formed at the crack tip. In addition, the effect of tie-layer thickness on the multilayer tensile properties was correlated with the delamination behavior. The fracture strain of the multilayers decreased with decreasing tie-layer thickness. Examination of the prefracture damage mechanism of stretched multilayers revealed good correlation with the delamination toughness of the tie-layers. In thick tie-layers (>2microm) the delamination toughness of the tie-layers was large enough to prevent delamination of multilayers when they were stretched. In the thin tie-layers (<2microm) the delamination toughness of all the tie-layers is low and consequently delamination led to premature fracture in stretched multilayers. Chapter 2. The kinetics of interdiffusion in the layer multiplying coextrusion process was studied between the miscible Nylon-6 and EVOH pair. The interdiffusion was followed by studying multilayer films of alternating Nylon-6 and EVOH layers that were coextruded with increasing number of layers. The AFM confirmed that the layers interdiffused with increasing number of layers and were forced to a homogeneous blend after several multiplications. The oxygen permeability of Nylon-6/EVOH multilayers was strongly affected by the amount of interdiffusion. The symmetry of the multilayers made it possible to model the composition profile through the layer thickness by application of Fick's law of

  13. Determination of three-dimensional imaging properties of a light microscope system. Partial confocal behavior in epifluorescence microscopy.

    PubMed Central

    Hiraoka, Y; Sedat, J W; Agard, D A

    1990-01-01

    We have determined the three-dimensional image-forming properties of an epifluorescence microscope for use in obtaining very high resolution three-dimensional images of biological structures by image processing methods. Three-dimensional microscopic data is collected as a series of two-dimensional images recorded at different focal planes. Each of these images contains not only in-focus information from the region around the focal plane, but also out-of-focus contributions from the remainder of the specimen. Once the imaging properties of the microscope system are characterized, powerful image processing methods can be utilized to remove the out-of-focus information and to correct for image distortions. Although theoretical calculations for the behavior of an aberration-free microscope system are available, the properties of real lenses under the conditions used for biological observation are often far from an ideal. For this reason, we have directly determined the image-forming properties of an epifluorescence microscope under conditions relevant to biological observations. Through-focus series of a point object (fluorescently-coated microspheres) were recorded on a charge-coupled device image detector. From these images, the three-dimensional point spread function and its Fourier transform, the optical transfer function, were derived. There were significant differences between the experimental results and the theoretical models which have important implications for image processing. The discrepancies can be explained by imperfections of the microscope system, nonideal observation conditions, and partial confocal effects found to occur with epifluorescence illumination. Understanding the optical behavior of the microscope system has indicated how to optimize specimen preparation, data collection, and processing protocols to obtain significantly improved images. Images FIGURE 2 FIGURE 4 FIGURE 5 FIGURE 7 PMID:2317554

  14. Many-body GW calculations of ground-state properties: quasi-2D electron systems and van der Waals forces.

    PubMed

    García-González, P; Godby, R W

    2002-02-04

    We present GW many-body results for ground-state properties of two simple but very distinct families of inhomogeneous systems in which traditional implementations of density-functional theory (DFT) fail drastically. The GW approach gives notably better results than the well-known random-phase approximation, at a similar computational cost. These results establish GW as a superior alternative to standard DFT schemes without the expensive numerical effort required by quantum Monte Carlo simulations.

  15. Characterization of cure in model photocrosslinking acrylate systems: Relationships among tensile properties, Tg and ultraviolet dose

    SciTech Connect

    Rakas, M.A.

    1996-10-01

    The extent of cure of a thermosetting polymer is governed largely by polymerization kinetics and the difference between the polymerization temperature and the material`s ultimate glass transition temperature (Tg). For prepolymers which cure when exposed to ultraviolet (UV) radiation, other factors which strongly determine the extent of cure are the UV intensity and exposure time, and the interrelationship between the optical absorbance of the photoinitiator (PI) and the rate of formation of excited state PI radicals. Beers` Law can be used to understand the relationship between the PI`s molar absorptivity, its concentration, and adhesive film thickness. Many adhesives users are more concerned with bulk properties such as tensile modulus and Tg rather than a numerical measurement of degree of cure. Therefore, this research employed model acrylate formulations and determined changes in tensile properties and Tg as a function of film thickness and UV dose. These results enabled correlation of bulk and photoinitiator properties.

  16. Mechanical properties of a mature biofilm from a wastewater system: from microscale to macroscale level.

    PubMed

    Safari, Ashkan; Tukovic, Zeljko; Walter, Maik; Casey, Eoin; Ivankovic, Alojz

    2015-01-01

    A fundamental understanding of biofilm mechanical stability is critical in order to describe detachment and develop biofouling control strategies. It is thus important to characterise the elastic deformation and flow behaviour of the biofilm under different modes of applied force. In this study, the mechanical properties of a mature wastewater biofilm were investigated with methods including macroscale compression and microscale indentation using atomic force microscopy (AFM). The mature biofilm was found to be mechanically isotropic at the macroscale level as its mechanical properties did not depend on the scales and modes of loading. However, the biofilm showed a tendency for mechanical inhomogeneity at the microscale level as indentation progressed deeper into the matrix. Moreover, it was observed that the adhesion force had a significant influence on the elastic properties of the biofilm at the surface, subjected to microscale tensile loading. These results are expected to inform a damage-based model for biofilm detachment.

  17. Cellular and network properties in the functioning of the nervous system: from central pattern generators to cognition.

    PubMed

    Arshavsky, Yuri I

    2003-03-01

    The relation between individual neurons and neuronal networks in performing brain functions is one of the central questions in modern neuroscience. Most of the current literature suggests that the role of individual neurons is negligible and neural networks play a dominant role in the functioning of the nervous system. Individual neurons are usually viewed as network elements whose functions are limited to generating electrical signals and releasing neurotransmitters. Here I summarize experimental evidence that challenges this concept and argue that the unique, intrinsic properties of highly specialized individual neurons are as important for the functioning of the brain as the network properties. I first discuss the studies of relatively 'simple' functions of the nervous system, such as the control of rhythmic 'automatic' movements and generation of circadian rhythm, which indicate that individual neurons may continue performing their functions after being separated from corresponding networks. I then argue that the complex cognitive functions, such as declarative memory, language processing, and face recognition, are likely to be underlain by the properties of groups of highly specialized neurons. These neurons appear to be genetically predisposed to perform cognitive functions and their dysfunctions cannot be compensated by other elements of the nervous system. Under this concept, the electrical signals circulating within and between neural networks are considered to be a means of forming coordinated dynamic ensembles of neurons involved in performing specific functions. While still speculative, this hypothesis may provoke new approaches to studies of neural mechanisms underpinning cognitive functions of the brain.

  18. Characterization and prediction of haploinsufficiency using systems-level gene properties in yeast.

    PubMed

    Norris, Matthew; Lovell, Simon; Delneri, Daniela

    2013-11-06

    Variation in gene copy number can significantly affect organism fitness. When one allele is missing in a diploid, the phenotype can be compromised because of haploinsufficiency. In this work, we identified associations between Saccharomyces cerevisiae gene properties and genome-scale haploinsufficiency phenotypes from previous work. We compared the haploinsufficiency profiles against 23 gene properties and found that genes with higher level of connectivity (degree) in a protein-protein interaction network, higher genetic interaction degree, greater gene sequence conservation, and higher protein expression were significantly more likely to be haploinsufficient. Additionally, haploinsufficiency showed negative relationships with cell cycle regulation and promoter sequence conservation.

  19. Negative differential gain in quantum dot systems: Interplay of structural properties and many-body effects

    SciTech Connect

    Goldmann, E. Jahnke, F.; Lorke, M.; Frauenheim, T.

    2014-06-16

    The saturation behaviour of optical gain with increasing excitation density is an important factor for laser device performance. For active materials based on self-organized InGaAs/GaAs quantum dots, we study the interplay between structural properties of the quantum dots and many-body effects of excited carriers in the optical properties via a combination of tight-binding and quantum-kinetic calculations. We identify regimes where either phase-space filling or excitation-induced dephasing dominates the saturation behavior of the optical gain. The latter can lead to the emergence of a negative differential material gain.

  20. Structural analysis and optical properties of the Bi2–xYxWO6 system

    PubMed Central

    Pasternak, S.; Levy, D.; Paz, Y.

    2016-01-01

    Photocatalytic conversion of solar energy into chemical energy has attracted considerable interest for several decades. One compound already reported as a visible-light-active photocatalyst for water splitting is BiYWO6, a member of the Bi2–xYxWO6 family of compounds. The structural and optical properties of other members of this family have not been reported to date. In this work, we synthesized various compositions of Bi2–xYxWO6, studied their optical properties, and report their structural parameters obtained by utilizing powder diffraction coupled with Rietveld refinement. PMID:28066155

  1. Dynamical Spin Properties of Confined Fermi and Bose Systems in the Presence of Spin-Orbit Coupling

    NASA Astrophysics Data System (ADS)

    Ambrosetti, A.; Salasnich, L.; Silvestrelli, P. L.

    2016-10-01

    Due to the recent experimental progress, tunable spin-orbit (SO) interactions represent ideal candidates for the control of polarization and dynamical spin properties in both quantum wells and cold atomic systems. A detailed understanding of spin properties in SO-coupled systems is thus a compelling prerequisite for possible novel applications or improvements in the context of spintronics and quantum computers. Here, we analyze the case of equal Rashba and Dresselhaus couplings in both homogeneous and laterally confined two-dimensional systems. Starting from the single-particle picture and subsequently introducing two-body interactions we observe that periodic spin fluctuations can be induced and maintained in the system. Through an analytical derivation, we show that the two-body interaction does not involve decoherence effects in the bosonic dimer, and, in the repulsive homogeneous Fermi gas, it may be even exploited in combination with the SO coupling to induce and tune standing currents. By further studying the effects of a harmonic lateral confinement—a particularly interesting case for Bose condensates—we evidence the possible appearance of nontrivial spin textures, whereas the further application of a small Zeeman-type interaction can be exploited to fine-tune the system's polarizability.

  2. Sensitivity of emergent sociohydrologic dynamics to internal system properties and external sociopolitical factors: Implications for water management

    NASA Astrophysics Data System (ADS)

    Elshafei, Y.; Tonts, M.; Sivapalan, M.; Hipsey, M. R.

    2016-06-01

    It is increasingly acknowledged that effective management of water resources requires a holistic understanding of the coevolving dynamics inherent in the coupled human-hydrology system. One of the fundamental information gaps concerns the sensitivity of coupled system feedbacks to various endogenous system properties and exogenous societal contexts. This paper takes a previously calibrated sociohydrology model and applies an idealized implementation, in order to: (i) explore the sensitivity of emergent dynamics resulting from bidirectional feedbacks to assumptions regarding (a) internal system properties that control the internal dynamics of the coupled system and (b) the external sociopolitical context; and (ii) interpret the results within the context of water resource management decision making. The analysis investigates feedback behavior in three ways, (a) via a global sensitivity analysis on key parameters and assessment of relevant model outputs, (b) through a comparative analysis based on hypothetical placement of the catchment along various points on the international sociopolitical gradient, and (c) by assessing the effects of various direct management intervention scenarios. Results indicate the presence of optimum windows that might offer the greatest positive impact per unit of management effort. Results further advocate management tools that encourage an adaptive learning, community-based approach with respect to water management, which are found to enhance centralized policy measures. This paper demonstrates that it is possible to use a place-based sociohydrology model to make abstractions as to the dynamics of bidirectional feedback behavior, and provide insights as to the efficacy of water management tools under different circumstances.

  3. [Activity of antioxidant system of Aspergillus versicolor with radioadaptive properties under conditions of exposure to radiation].

    PubMed

    Tuhaĭ, T I

    2011-01-01

    Melanin pigments were revealed for the first time in Aspergillus versicolor strains. Ionizing irradiation practically did not influence melanin synthesis in A. versicolor strains with radioadaptive properties and stimulated its synthesis in the control strain, which did not show such properties. High level of superoxide dismutase activity (from 100 up to 720 U/mg of protein) was revealed in the investigated strains. The irradiation in exponential phase of growth did not practically influence or raised activity of superoxide dismutase (SOD) in the strains with radioadaptive properties and oppressed its activity in the control strain. The irradiation in a stationary phase was accompanied by a decrease of SOD activity in the strains with radioadaptive properties, and essential (2 times) increase of SOD activity in the control strain and strain A. versicolor 101, which did not show radiotropism. The extracellular catalase activity (1.52-37.04 mmol x min(-1) x mg(-1) protein) exceeded by more than an order the intracellular one (8-230 mol x min(-1) x mg(-1) protein) in the investigated strains.

  4. Photophysical and antibacterial properties of complex systems based on smectite, a cationic surfactant and methylene blue.

    PubMed

    Donauerová, Alena; Bujdák, Juraj; Smolinská, Miroslava; Bujdáková, Helena

    2015-10-01

    Solid or colloidal materials with embedded photosensitizers are promising agents from the medical or environmental perspective, where the direct use of photoactive solutions appears to be problematic. Colloids based on layered silicates of the saponite (Sap) and montmorillonite (Mon) type, including those modified with dodecylammonium cations (C12) and photosensitizer--methylene blue (MB) were studied. Two representatives of bacteria, namely Enterobacter cloacae and Escherichia coli, were selected for this work. A spectral study showed that MB solutions and also colloids with Sap including C12 exhibited the highest photoactivities. The antimicrobial properties of the smectite colloids were not directly linked to the photoactivity of the adsorbed MB cations. They were also influenced by other parameters, such as light vs. dark conditions, the spectrum, power and duration of the light used for the irradiation; growth phases, and the pre-treatment of microorganisms. Both the photoactivity and antimicrobial properties of the colloids were improved upon pre-modification with C12. Significantly higher antimicrobial properties were observed for the colloids based on Mon with MB in the form of molecular aggregates without significant photoactivities. The MB/Mon colloids, both modified and non-modified with C12 cations, exhibited higher antimicrobial effects than pure MB solution. Besides the direct effect of photosensitization, the surface properties of the silicate particles likely played a crucial role in the interactions with microorganisms.

  5. Hydraulic properties affected by topsoil thickness in switchgrass and corn-soybean cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Loss of productive topsoil by soil erosion over time can reduce the productive capacity of soil and can significantly affect soil hydraulic properties. This study evaluated the effects of reduced topsoil thickness and perennial switchgrass (Panicum virgatum L.) versus corn (Zea mays L.)/soybean [Gly...

  6. A "Uniform" Education: Reform of Local Property Tax School Finance Systems through State Constitutions.

    ERIC Educational Resources Information Center

    Kaster, James H.

    1979-01-01

    Examines Wisconsin's school finance system in light of recent legislation and the education clause in the state constitution. Argues for judicial involvement to correct the finance system. Available from Marquette Law Review, 1103 West Wisconsin Ave., Milwaukee, WI 53233. (IRT)

  7. Software Requirements Specification of A Proposed Plant Property Management Information System for the Naval Postgraduate School.

    DTIC Science & Technology

    1982-12-01

    information system (MIS) to support Plant Account equipment related functions could eliminate data handling redundancy and improved Plant Account...system users and accountability for more than 2000 individual equipment items worth over seven million dollars. Implementation of a management

  8. Influence of anharmonic effects on the structural-mechanical and thermophysical properties of filled polymer systems

    SciTech Connect

    Bordyuk, N.A.; Nikitchuk, V.I.; Voloshin, O.M.

    1995-08-01

    The force constants of anharmonicity, the total energy, and the force of interaction between structural elements of PVC systems are determined from the values of the quasielastic constants of filled polymer systems.

  9. Influence of anharmonic effects on the structural-mechanical and thermophysical properties of filled polymer systems

    NASA Astrophysics Data System (ADS)

    Bordyuk, N. A.; Nikitchuk, V. I.; Voloshin, O. M.; Lipatov, Yu. S.; Kolupaev, B. S.

    1995-01-01

    The force constants of anharmonicity, the total energy, and the force of interaction between structural elements of PVC systems are determined from the values of the quasielastic constants of filled polymer systems.

  10. Chemical and biological properties of supramolecular polymer systems based on oligocaprolactones.

    PubMed

    Dankers, Patricia Y W; van Leeuwen, Ellen N M; van Gemert, Gaby M L; Spiering, A J H; Harmsen, Martin C; Brouwer, Linda A; Janssen, Henk M; Bosman, Anton W; van Luyn, Marja J A; Meijer, E W

    2006-11-01

    We show that materials with a diverse range of mechanical and biological properties can be obtained using a modular approach by simply mixing different ratios of oligocaprolactones that are either end-functionalized or chain-extended with quadruple hydrogen bonding ureido-pyrimidinone (UPy) moieties. The use of two UPy-synthons allows for easy synthesis of UPy-modified polymers resulting in high yields. Comparison of end-functionalized UPy-polymers with chain-extended UPy-polymers shows that these polymers behave distinctively different regarding their material and biological properties. The end-modified UPy-polymer is rather stiff and brittle due to its high crystallinity. Disks made of this material fractures after subcutaneous implantation. The material shows a low inflammatory response which is accompanied by the formation of a fibrous capsule, reflecting the inertness of the material. The chain-extended UPy-material on the contrary is practically free of crystalline domains and shows clear flexible properties. This material deforms after in-vivo implantation, accompanied with cellular infiltration. By mixing both polymers, materials with intermediate properties concerning their mechanical and biological behaviour can be obtained. Surprisingly, a 20:80 mixture of both polymers with the chain-extended UPy-polymer in excess shows flexible properties without visible deformation upon implantation for 42 days. This mixture, a blend formed by intimate mixing through UPy-UPy interaction, also shows a mild tissue response accompanied with the formation of a thin capsule. The material does not become more crystalline upon implantation. Hence, this mixture might be an ideal scaffold material for soft tissue engineering due to its flexibility and diminished fibrous tissue formation, and illustrates the strength of the modular approach.

  11. How do the physical properties of ice influence the habitability of outer solar system satellites? (Invited)

    NASA Astrophysics Data System (ADS)

    Nimmo, F.

    2009-12-01

    A possible definition of a habitable environment is one that has liquid water, a range of suitable prebiotic compounds (however defined), and a source of energy. An ocean-bearing icy satellite can provide the first two quite easily, as well as giving protection from radiation. The third requirement is most readily provided by redox reactants, which may arise from hydrothermal activity, solar ultraviolet radiation, or impacts [1-4]. Reactants produced at the surface must thus be transported through the ice shell to the underlying liquid, while hydrothermal activity requires contact between hot silicates and the ocean. Large satellites, such as Ganymede, possessing denser ice phases beneath the ocean are thus less plausibly habitable. As far as ice properties are concerned, there are two key issues. The first is the ability of ice to insulate an underlying ocean, thus controlling its lifetime. This depends on whether the ice is convecting (which in turn depends on grain size, shell thickness, basal temperature etc. [5]), the extent to which the ice shell is tidally heated, and the thermal conductivity of the ice (clathrates are good insulators [6]). For instance, Enceladus is sufficiently small that its putative ocean is expected to freeze on timescales of tens of Myr [7], reducing its potential habitability. On the other hand, ice shells above ammonia-rich oceans are likely to have lower basal temperatures and thus freeze more slowly [8]. The second issue is the extent to which the ice allows communication between the surface and subsurface. Getting material from the surface to the ocean, or vice versa, is difficult because convecting ice typically has a thick, stagnant lid [9]. But there may be situations in which this stagnant lid does not occur, for instance if the ice has a low yield strength. Brittle failure might also allow communication between the ocean and the surface [9] (as appears to happen at Enceladus [10]), while melt production due to shear heating

  12. Quantitative electron spin resonance (ESR) analysis of antioxidative properties using the acetaldehyde/xanthine oxidase system

    NASA Astrophysics Data System (ADS)

    Souchard, J.-P.; Nepveu, F.

    1998-05-01

    We present a method for the quantitative ESR analysis of the antioxidant properties of drugs using the acetaldhehyde/xanthine oxidase (AC/XOD) superoxide generating system and 5,5-dimethyl-l-pyrroline-N-oxide (DMPO) as spin trap. In stoichiometric conditions (AC/XOD, 60 mM/0.018 U), the resulting paramagnetic DMPO adduct disappeared with superoxide dismutase and remained when catalase or DMSO were used. That adduct was dependent only on superoxide and resulted from the trapping of a carboxyl radical by DMPO (aN = 15.2 G, aH = 18.9 G). Similar results were obtained using 4-pyridyl-l-oxide-N-t-butyl nitrone (POBN) as spin trap. The ESR signal of the DMPO-CO2- adduct was very stable and allowed quantitative analysis of the antioxidative activity of redox molecules from an IC{50} value representing the concentration causing 50% inhibition of its intensity. Among the tested compounds, manganese(II), complexes were the most effective, 25 times as active as ascorbic acid or (+)catechin and 500-fold more antioxidative than Trolox^R. Nous présentons une méthode d'analyse quantitative de l'activité antioxydante de composés d'intérêt pharmaceutique basée sur le système acétaldéhyde/xanthine oxydase (AC/XOD), l'utilisation de la RPE et du piégeage de spin avec le 5,5-diméthyl-l-pyrroline-N-oxyde (DMPO). Dans les conditions stoechiométriques {AC/XOD, 60 mM/0,018 U/ml}, l'adduit radicalaire résultant de ce système disparaît en présence de superoxyde dismutase et persiste en présence de catalase ou de DMSO. Cet adduit ne dépend que de la présence de l'anion superoxyde et provient du piégeage d'un radical carboxyle CO2- sur le DMPO (aN = 15.2 G, aH = 18.9 G). Des résultats similaires ont été obtenus avec le piégeur de spin 4-pyridyl-l-oxyde-N-t-butyl nitrone (POBN). Le signal RPE de l'adduit DMPO-CO2- est très stable et permet la quantification de l'activité antioxydante de pharmacophores redox par la détermination de la CI{50}, concentration qui

  13. Optical devices having flakes suspended in a host fluid to provide a flake/fluid system providing flakes with angularly dependent optical properties in response to an alternating current electric field due to the dielectric properties of the system

    SciTech Connect

    Kosc, Tanya Z.; Marshall, Kenneth L.; Jacobs, Stephen D.

    2006-05-09

    Optical devices utilizing flakes (also called platelets) suspended in a host fluid have optical characteristics, such as reflective properties, which are angular dependent in response to an AC field. The reflectivity may be Bragg-like, and the characteristics are obtained through the use of flakes of liquid crystal material, such as polymer liquid crystal (PLC) materials including polymer cholesteric liquid crystal (PCLC) and polymer nematic liquid crystal (PNLC) material or birefringent polymers (BP). The host fluid may be propylene carbonate, poly(ethylene glycol) or other fluids or fluid mixtures having fluid conductivity to support conductivity in the flake/host system. AC field dependent rotation of 90.degree. can be obtained at rates and field intensities dependent upon the frequency and magnitude of the AC field. The devices are useful in providing displays, polarizers, filters, spatial light modulators and wherever switchable polarizing, reflecting, and transmission properties are desired.

  14. Transport of the aromatic amino acids into isolated rat liver cells. Properties of uptake by two distinct systems.

    PubMed Central

    Salter, M; Knowles, R G; Pogson, C I

    1986-01-01

    The transport of the aromatic amino acids into isolated rat liver cells was studied. There was a rapid and substantial binding of the aromatic amino acids, L-alanine and L-leucine to the plasma membrane. This has important consequences for the determination of rates of transport and intracellular concentrations of the amino acids. Inhibition studies with a variety of substrates of various transport systems gave results consistent with aromatic amino acid transport being catalysed by two systems: a 2-aminobicyclo(2,2,1)heptane-2-carboxylic acid (BCH)-insensitive aromatic D- and L-amino acid-specific system, and the L-type system (BCH-sensitive). The BCH-insensitive component of transport was Na+-independent and facilitated non-concentrative transport of the aromatic amino acids; it was unaffected by culture of liver cells for 24 h, by 48 h starvation, dexamethasone phosphate or glucagon. Kinetic properties of the BCH-inhibitable component were similar to those previously reported for the L2-system in liver cells. The BCH-insensitive component was a comparatively low-Km low-Vmax. transport system that we suggest is similar to the T-transport system previously seen only in human red blood cells. The results are discussed with reference to the importance of the T- and L-systems in the control of aromatic L-amino acid degradation in the liver. PMID:3954748

  15. Seismic properties of fluid bearing formations in magmatic geothermal systems: can we directly detect geothermal activity with seismic methods?

    NASA Astrophysics Data System (ADS)

    Grab, Melchior; Scott, Samuel; Quintal, Beatriz; Caspari, Eva; Maurer, Hansruedi; Greenhalgh, Stewart

    2016-04-01

    Seismic methods are amongst the most common techniques to explore the earth's subsurface. Seismic properties such as velocities, impedance contrasts and attenuation enable the characterization of the rocks in a geothermal system. The most important goal of geothermal exploration, however, is to describe the enthalpy state of the pore fluids, which act as the main transport medium for the geothermal heat, and to detect permeable structures such as fracture networks, which control the movement of these pore fluids in the subsurface. Since the quantities measured with seismic methods are only indirectly related with the fluid state and the rock permeability, the interpretation of seismic datasets is difficult and usually delivers ambiguous results. To help overcome this problem, we use a numerical modeling tool that quantifies the seismic properties of fractured rock formations that are typically found in magmatic geothermal systems. We incorporate the physics of the pore fluids, ranging from the liquid to the boiling and ultimately vapor state. Furthermore, we consider the hydromechanics of permeable structures at different scales from small cooling joints to large caldera faults as are known to be present in volcanic systems. Our modeling techniques simulate oscillatory compressibility and shear tests and yield the P- and S-wave velocities and attenuation factors of fluid saturated fractured rock volumes. To apply this modeling technique to realistic scenarios, numerous input parameters need to be indentified. The properties of the rock matrix and individual fractures were derived from extensive literature research including a large number of laboratory-based studies. The geometries of fracture networks were provided by structural geologists from their published studies of outcrops. Finally, the physical properties of the pore fluid, ranging from those at ambient pressures and temperatures up to the supercritical conditions, were taken from the fluid physics

  16. Frequency domain photothermoacoustic signal amplitude dependence on the optical properties of water: turbid polyvinyl chloride-plastisol system.

    PubMed

    Spirou, Gloria M; Mandelis, Andreas; Vitkin, I Alex; Whelan, William M

    2008-05-10

    Photoacoustic (more precisely, photothermoacoustic) signals generated by the absorption of photons can be related to the incident laser fluence rate. The dependence of frequency domain photoacoustic (FD-PA) signals on the optical absorption coefficient (micro(a)) and the effective attenuation coefficient (micro(eff)) of a turbid medium [polyvinyl chloride-plastisol (PVCP)] with tissuelike optical properties was measured, and empirical relationships between these optical properties and the photoacoustic (PA) signal amplitude and the laser fluence rate were derived for the water (PVCP system with and without optical scatterers). The measured relationships between these sample optical properties and the PA signal amplitude were found to be linear, consistent with FD-PA theory: micro(a)=a(A/Phi)-b and micro(eff)=c(A/Phi)+d, where Phi is the laser fluence, A is the FD-PA amplitude, and a, ...,d are empirical coefficients determined from the experiment using linear frequency-swept modulation and a lock-in heterodyne detection technique. This quantitative technique can easily be used to measure the optical properties of general turbid media using FD-PAs.

  17. Associations Between the Molecular and Optical Properties of Dissolved Organic Matter in the Florida Everglades, a Model Coastal Wetland System

    PubMed Central

    Wagner, Sasha; Jaffé, Rudolf; Cawley, Kaelin; Dittmar, Thorsten; Stubbins, Aron

    2015-01-01

    Optical properties are easy-to-measure proxies for dissolved organic matter (DOM) composition, source, and reactivity. However, the molecular signature of DOM associated with such optical parameters remains poorly defined. The Florida coastal Everglades is a subtropical wetland with diverse vegetation (e.g., sawgrass prairies, mangrove forests, seagrass meadows) and DOM sources (e.g., terrestrial, microbial, and marine). As such, the Everglades is an excellent model system from which to draw samples of diverse origin and composition to allow classically-defined optical properties to be linked to molecular properties of the DOM pool. We characterized a suite of seasonally- and spatially-collected DOM samples using optical measurements (EEM-PARAFAC, SUVA254, S275−295, S350−400, SR, FI, freshness index, and HIX) and ultrahigh resolution mass spectrometry (FTICR-MS). Spearman's rank correlations between FTICR-MS signal intensities of individual molecular formulae and optical properties determined which molecular formulae were associated with each PARAFAC component and optical index. The molecular families that tracked with the optical indices were generally in agreement with conventional biogeochemical interpretations. Therefore, although they represent only a small portion of the bulk DOM pool, absorbance, and fluorescence measurements appear to be appropriate proxies for the aquatic cycling of both optically-active and associated optically-inactive DOM in coastal wetlands. PMID:26636070

  18. Associations between the molecular and optical properties of dissolved organic matter in the Florida Everglades, a model coastal wetland system

    NASA Astrophysics Data System (ADS)

    Wagner, Sasha; Jaffe, Rudolf; Cawley, Kaelin; Dittmar, Thorsten; Stubbins, Aron

    2015-11-01

    Optical properties are easy-to-measure proxies for dissolved organic matter (DOM) composition, source and reactivity. However, the molecular signature of DOM associated with such optical parameters remains poorly defined. The Florida coastal Everglades is a subtropical wetland with diverse vegetation (e.g., sawgrass prairies, mangrove forests, seagrass meadows) and DOM sources (e.g., terrestrial, microbial and marine). As such, the Everglades is an excellent model system from which to draw samples of diverse origin and composition to allow classically-defined optical properties to be linked to molecular properties of the DOM pool. We characterized a suite of seasonally- and spatially-collected DOM samples using optical measurements (EEM-PARAFAC, SUVA254, S275-295, S350-400, SR, FI, freshness index and HIX) and ultrahigh resolution mass spectrometry (FTICR-MS). Spearman’s rank correlations between FTICR-MS signal intensities of individual molecular formulae and optical properties determined which molecular formulae were associated with each PARAFAC component and optical index. The molecular families that tracked with the optical indices were generally in agreement with conventional biogeochemical interpretations. Therefore, although they represent only a small portion of the bulk DOM pool, absorbance and fluorescence measurements appear to be appropriate proxies for the aquatic cycling of both optically-active and associated optically-inactive DOM in coastal wetlands.

  19. Caramel as a Model System for Evaluating the Roles of Mechanical Properties and Oral Processing on Sensory Perception of Texture.

    PubMed

    Wagoner, Ty B; Luck, Paige J; Foegeding, E Allen

    2016-03-01

    Food formulation can have a significant impact on texture perception during oral processing. We hypothesized that slight modifications to caramel formulations would significantly alter mechanical and masticatory parameters, which can be used to explain differences in texture perception. A multidisciplinary approach was applied by evaluating relationships among mechanical properties, sensory texture, and oral processing. Caramels were utilized as a highly adhesive and cohesive model system and the formulation was adjusted to generate distinct differences in sensory hardness and adhesiveness. Descriptive analysis was used to determine sensory texture, and mechanical properties were evaluated by oscillatory rheology, creep recovery, and pressure sensitive tack measurements. Oral processing was measured by determining activity of anterior temporalis and masseter muscles via electromyography and tracking jaw movement during chewing. The substitution of agar or gelatin for corn syrup at 0.6% w/w of the total formulation resulted in increased sensory hardness and decreased adhesiveness. Creep recovery and pressure sensitive tack testing were more effective at differentiating among treatments than oscillatory rheology. Hardness correlated inversely with creep compliance, and both stickiness and tooth adhesiveness correlated with pressure sensitive adhesive force. Harder samples, despite being less adhesive, were associated with increased muscle activity and jaw movement during mastication. Tooth packing, not linked with any mechanical property, correlated with altered jaw movement. The combination of material properties and oral processing parameters were able to explain all sensory texture differences in a highly adhesive food.

  20. Correlation between structure and physical properties of chalcogenide glasses in the AsxSe1-x system

    NASA Astrophysics Data System (ADS)

    Yang, Guang; Bureau, Bruno; Rouxel, Tanguy; Gueguen, Yann; Gulbiten, Ozgur; Roiland, Claire; Soignard, Emmanuel; Yarger, Jeffery L.; Troles, Johann; Sangleboeuf, Jean-Christophe; Lucas, Pierre

    2010-11-01

    Physical properties of chalcogenide glasses in the AsxSe1-x system have been measured as a function of composition including the Young’s modulus E , shear modulus G , bulk modulus K , Poisson’s ratio ν , the density ρ , and the glass transition Tg . All these properties exhibit a relatively sharp extremum at the average coordination number ⟨r⟩=2.4 . The structural origin of this trend is investigated by Raman spectroscopy and nuclear magnetic resonance. It is shown that the reticulation of the glass structure increases continuously until x=0.4 following the “chain crossing model” and then undergoes a transition toward a lower dimension pyramidal network containing an increasing number of molecular inclusions at x>0.4 . Simple theoretical estimates of the network bonding energy confirm a mismatch between the values of mechanical properties measured experimentally and the values predicted from a continuously reticulated structure, therefore corroborating the formation of a lower dimension network at high As content. The evolution of a wide range of physical properties is consistent with this sharp structural transition and suggests that there is no intermediate phase in these glasses at room temperature.