WorldWideScience

Sample records for surface potential measurements

  1. Measuring surface flow velocity with smartphones: potential for citizen observatories

    Science.gov (United States)

    Weijs, Steven V.; Chen, Zichong; Brauchli, Tristan; Huwald, Hendrik

    2014-05-01

    Stream flow velocity is an important variable for discharge estimation and research on sediment dynamics. Given the influence of the latter on rating curves (stage-discharge relations), and the relative scarcity of direct streamflow measurements, surface velocity measurements can offer important information for, e.g., flood warning, hydropower, and hydrological science and engineering in general. With the growing amount of sensing and computing power in the hands of more outdoorsy individuals, and the advances in image processing techniques, there is now a tremendous potential to obtain hydrologically relevant data from motivated citizens. This is the main focus of the interdisciplinary "WeSenseIt" project, a citizen observatory of water. In this subproject, we investigate the feasibility of stream flow surface velocity measurements from movie clips taken by (smartphone-) cameras. First results from movie-clip derived velocity information will be shown and compared to reference measurements.

  2. Surface contact potential patches and Casimir force measurements

    International Nuclear Information System (INIS)

    Kim, W. J.; Sushkov, A. O.; Lamoreaux, S. K.; Dalvit, D. A. R.

    2010-01-01

    We present calculations of contact potential surface patch effects that simplify previous treatments. It is shown that, because of the linearity of Laplace's equation, the presence of patch potentials does not affect an electrostatic calibration of a two-plate Casimir measurement apparatus. Using models that include long-range variations in the contact potential across the plate surfaces, a number of experimental observations can be reproduced and explained. For these models, numerical calculations show that if a voltage is applied between the plates which minimizes the force, a residual electrostatic force persists, and that the minimizing potential varies with distance. The residual force can be described by a fit to a simple two-parameter function involving the minimizing potential and its variation with distance. We show the origin of this residual force by use of a simple parallel capacitor model. Finally, the implications of a residual force that varies in a manner different from 1/d on the accuracy of previous Casimir measurements is discussed.

  3. Surface characterization of hemodialysis membranes based on streaming potential measurements.

    Science.gov (United States)

    Werner, C; Jacobasch, H J; Reichelt, G

    1995-01-01

    Hemodialysis membranes made from cellulose (CUPROPHAN, HEMOPHAN) and sulfonated polyethersulfone (SPES) were characterized using the streaming potential technique to determine the zeta potential at their interfaces against well-defined aqueous solutions of varied pH and potassium chloride concentrations. Streaming potential measurements enable distinction between different membrane materials. In addition to parameters of the electrochemical double layer at membrane interfaces, thermodynamic characteristics of adsorption of different solved species were evaluated. For that aim a description of double layer formation as suggested by Börner and Jacobasch (in: Electrokinetic Phenomena, p. 231. Institut für Technologie der Polymere, Dresden (1989)) was applied which is based on the generally accepted model of the electrochemical double layer according to Stern (Z. Elektrochemie 30, 508 (1924)) and Grahame (Chem. Rev. 41, 441 (1947)). The membranes investigated show different surface acidic/basic and polar/nonpolar behavior. Furthermore, alterations of membrane interfaces through adsorption processes of components of biologically relevant solutions were shown to be detectable by streaming potential measurements.

  4. Surface Complexation Modeling of Calcite Zeta Potential Measurement in Mixed Brines for Carbonate Wettability Characterization

    Science.gov (United States)

    Song, J.; Zeng, Y.; Biswal, S. L.; Hirasaki, G. J.

    2017-12-01

    We presents zeta potential measurements and surface complexation modeling (SCM) of synthetic calcite in various conditions. The systematic zeta potential measurement and the proposed SCM provide insight into the role of four potential determining cations (Mg2+, SO42- , Ca2+ and CO32-) and CO2 partial pressure in calcite surface charge formation and facilitate the revealing of calcite wettability alteration induced by brines with designed ionic composition ("smart water"). Brines with varying potential determining ions (PDI) concentration in two different CO2 partial pressure (PCO2) are investigated in experiments. Then, a double layer SCM is developed to model the zeta potential measurements. Moreover, we propose a definition for contribution of charged surface species and quantitatively analyze the variation of charged species contribution when changing brine composition. After showing our model can accurately predict calcite zeta potential in brines containing mixed PDIs, we apply it to predict zeta potential in ultra-low and pressurized CO2 environments for potential applications in carbonate enhanced oil recovery including miscible CO2 flooding and CO2 sequestration in carbonate reservoirs. Model prediction reveals that pure calcite surface will be positively charged in all investigated brines in pressurized CO2 environment (>1atm). Moreover, the sensitivity of calcite zeta potential to CO2 partial pressure in the various brine is found to be in the sequence of Na2CO3 > Na2SO4 > NaCl > MgCl2 > CaCl2 (Ionic strength=0.1M).

  5. Probing surface charge potentials of clay basal planes and edges by direct force measurements.

    Science.gov (United States)

    Zhao, Hongying; Bhattacharjee, Subir; Chow, Ross; Wallace, Dean; Masliyah, Jacob H; Xu, Zhenghe

    2008-11-18

    The dispersion and gelation of clay suspensions have major impact on a number of industries, such as ceramic and composite materials processing, paper making, cement production, and consumer product formulation. To fundamentally understand controlling mechanisms of clay dispersion and gelation, it is necessary to study anisotropic surface charge properties and colloidal interactions of clay particles. In this study, a colloidal probe technique was employed to study the interaction forces between a silica probe and clay basal plane/edge surfaces. A muscovite mica was used as a representative of 2:1 phyllosilicate clay minerals. The muscovite basal plane was prepared by cleavage, while the edge surface was obtained by a microtome cutting technique. Direct force measurements demonstrated the anisotropic surface charge properties of the basal plane and edge surface. For the basal plane, the long-range forces were monotonically repulsive within pH 6-10 and the measured forces were pH-independent, thereby confirming that clay basal planes have permanent surface charge from isomorphic substitution of lattice elements. The measured interaction forces were fitted well with the classical DLVO theory. The surface potentials of muscovite basal plane derived from the measured force profiles were in good agreement with those reported in the literature. In the case of edge surfaces, the measured forces were monotonically repulsive at pH 10, decreasing with pH, and changed to be attractive at pH 5.6, strongly suggesting that the charge on the clay edge surfaces is pH-dependent. The measured force profiles could not be reasonably fitted with the classical DLVO theory, even with very small surface potential values, unless the surface roughness was considered. The surface element integration (SEI) method was used to calculate the DLVO forces to account for the surface roughness. The surface potentials of the muscovite edges were derived by fitting the measured force profiles with the

  6. Direct Measurement of Surface Dissolution Rates in Potential Nuclear Waste Forms: The Example of Pyrochlore.

    Science.gov (United States)

    Fischer, Cornelius; Finkeldei, Sarah; Brandt, Felix; Bosbach, Dirk; Luttge, Andreas

    2015-08-19

    The long-term stability of ceramic materials that are considered as potential nuclear waste forms is governed by heterogeneous surface reactivity. Thus, instead of a mean rate, the identification of one or more dominant contributors to the overall dissolution rate is the key to predict the stability of waste forms quantitatively. Direct surface measurements by vertical scanning interferometry (VSI) and their analysis via material flux maps and resulting dissolution rate spectra provide data about dominant rate contributors and their variability over time. Using pyrochlore (Nd2Zr2O7) pellet dissolution under acidic conditions as an example, we demonstrate the identification and quantification of dissolution rate contributors, based on VSI data and rate spectrum analysis. Heterogeneous surface alteration of pyrochlore varies by a factor of about 5 and additional material loss by chemo-mechanical grain pull-out within the uppermost grain layer. We identified four different rate contributors that are responsible for the observed dissolution rate range of single grains. Our new concept offers the opportunity to increase our mechanistic understanding and to predict quantitatively the alteration of ceramic waste forms.

  7. Surface potential measurement of negative-ion-implanted insulators by analysing secondary electron energy distribution

    International Nuclear Information System (INIS)

    Toyota, Yoshitaka; Tsuji, Hiroshi; Nagumo, Syoji; Gotoh, Yasuhito; Ishikawa, Junzo; Sakai, Shigeki.

    1994-01-01

    The negative ion implantation method we have proposed is a noble technique which can reduce surface charging of isolated electrodes by a large margin. In this paper, the way to specify the surface potential of negative-ion-implanted insulators by the secondary electron energy analysis is described. The secondary electron energy distribution is obtained by a retarding field type energy analyzer. The result shows that the surface potential of fused quartz by negative-ion implantation (C - with the energy of 10 keV to 40 keV) is negatively charged by only several volts. This surface potential is extremely low compared with that by positive-ion implantation. Therefore, the negative-ion implantation is a very effective method for charge-up free implantation without charge compensation. (author)

  8. Surface potential measurement of insulators in negative-ion implantation by secondary electron energy-peak shift

    International Nuclear Information System (INIS)

    Nagumo, Shoji; Toyota, Yoshitaka; Tsuji, Hiroshi; Gotoh, Yasuhito; Ishikawa, Junzo; Sakai, Shigeki; Tanjyo, Masayasu; Matsuda, Kohji.

    1993-01-01

    Negative-ion implantation is expected to realize charge-up free implantation. In this article, about a way to specify surface potential of negative-ion implanted insulator by secondary-electron-energy distribution, its principle and preliminary experimental results are described. By a measuring system with retarding field type energy analyzer, energy distribution of secondary electron from insulator of Fused Quartz in negative-carbon-ion implantation was measured. As a result the peak-shift of its energy distribution resulted according with the surface potential of insulator. It was found that surface potential of insulator is negatively charged by only several volts. Thus, negative-ion implanted insulator reduced its surface charge-up potential (without any electron supply). Therefore negative-ion implantation is considered to be much more effective method than conventional positive-ion implantation. (author)

  9. Surface potential measurement of the insulator with secondary electron caused by negative ion implantation

    International Nuclear Information System (INIS)

    Tsuji, Hiroshi; Toyota, Yoshitaka; Nagumo, Syoji; Gotoh, Yasuhito; Ishikawa, Junzo; Sakai, Shigeki; Tanjyo, Masayasu; Matsuda, Kohji.

    1994-01-01

    Ion implantation has the merit of the good controllability of implantation profile and low temperature process, and has been utilized for the impurity introduction in LSI production. However, positive ion implantation is carried out for insulator or insulated conductor substrates, their charged potential rises, which is a serious problem. As the requirement for them advanced, charge compensation method is not the effective means for resolving it. The negative ion implantation in which charging is little was proposed. When the experiment on the negative ion implantation into insulated conductors was carried out, it was verified that negative ion implantation is effective as the implantation process without charging. The method of determining the charged potential of insulators at the time of negative ion implantation by paying attention to the energy distribution of the secondary electrons emitted from substrates at the time was devised. The energy analyzer for measuring the energy distribution of secondary electrons was made, and the measurement of the charged potential of insulators was carried out. The principle of the measurement, the measuring system and the experimental results are reported. (K.I.)

  10. Potentials of surfaces in space

    International Nuclear Information System (INIS)

    Whipple, E.C.

    1981-01-01

    The potential of a body in space is determined by a balance between various charging currents such as the transfer of charge from plasma particles, photoemission, and secondary electron emission. These processes are evaluated for bodies in the solar system and in interstellar space under the headings; an overview of charging, survey of early work on charging, charging processes, effects of non-isotropic plasmas and magnetic and electric fields, calculation of surface potentials, differential charging, potential barriers and discharge processes, measurements of potential, potential modification and control on spacecraft, and astrophysical applications. (U.K.)

  11. The localization of focal heart activity via body surface potential measurements: tests in a heterogeneous torso phantom

    International Nuclear Information System (INIS)

    Wetterling, F; Liehr, M; Haueisen, J; Schimpf, P; Liu, H

    2009-01-01

    The non-invasive localization of focal heart activity via body surface potential measurements (BSPM) could greatly benefit the understanding and treatment of arrhythmic heart diseases. However, the in vivo validation of source localization algorithms is rather difficult with currently available measurement techniques. In this study, we used a physical torso phantom composed of different conductive compartments and seven dipoles, which were placed in the anatomical position of the human heart in order to assess the performance of the Recursively Applied and Projected Multiple Signal Classification (RAP-MUSIC) algorithm. Electric potentials were measured on the torso surface for single dipoles with and without further uncorrelated or correlated dipole activity. The localization error averaged 11 ± 5 mm over 22 dipoles, which shows the ability of RAP-MUSIC to distinguish an uncorrelated dipole from surrounding sources activity. For the first time, real computational modelling errors could be included within the validation procedure due to the physically modelled heterogeneities. In conclusion, the introduced heterogeneous torso phantom can be used to validate state-of-the-art algorithms under nearly realistic measurement conditions.

  12. The localization of focal heart activity via body surface potential measurements: tests in a heterogeneous torso phantom

    Science.gov (United States)

    Wetterling, F.; Liehr, M.; Schimpf, P.; Liu, H.; Haueisen, J.

    2009-09-01

    The non-invasive localization of focal heart activity via body surface potential measurements (BSPM) could greatly benefit the understanding and treatment of arrhythmic heart diseases. However, the in vivo validation of source localization algorithms is rather difficult with currently available measurement techniques. In this study, we used a physical torso phantom composed of different conductive compartments and seven dipoles, which were placed in the anatomical position of the human heart in order to assess the performance of the Recursively Applied and Projected Multiple Signal Classification (RAP-MUSIC) algorithm. Electric potentials were measured on the torso surface for single dipoles with and without further uncorrelated or correlated dipole activity. The localization error averaged 11 ± 5 mm over 22 dipoles, which shows the ability of RAP-MUSIC to distinguish an uncorrelated dipole from surrounding sources activity. For the first time, real computational modelling errors could be included within the validation procedure due to the physically modelled heterogeneities. In conclusion, the introduced heterogeneous torso phantom can be used to validate state-of-the-art algorithms under nearly realistic measurement conditions.

  13. Corrected body surface potential mapping.

    Science.gov (United States)

    Krenzke, Gerhard; Kindt, Carsten; Hetzer, Roland

    2007-02-01

    In the method for body surface potential mapping described here, the influence of thorax shape on measured ECG values is corrected. The distances of the ECG electrodes from the electrical heart midpoint are determined using a special device for ECG recording. These distances are used to correct the ECG values as if they had been measured on the surface of a sphere with a radius of 10 cm with its midpoint localized at the electrical heart midpoint. The equipotential lines of the electrical heart field are represented on the virtual surface of such a sphere. It is demonstrated that the character of a dipole field is better represented if the influence of the thorax shape is reduced. The site of the virtual reference electrode is also important for the dipole character of the representation of the electrical heart field.

  14. Potential photosynthesis of crop surfaces.

    NARCIS (Netherlands)

    Wit, de C.T.

    1959-01-01

    A formula for calculating the potential photosynthesis of a closed crop surface is proposed, assuming that the leaves of the crop are not arranged in any definite direction. In the Netherlands, values for potential photosynthesis vary from 290 kg. CH2O/ha./day in June to 50 kg./ha./day in December.

  15. Atom-surface potentials and atom interferometry

    International Nuclear Information System (INIS)

    Babb, J.F.

    1998-01-01

    Long-range atom-surface potentials characterize the physics of many actual systems and are now measurable spectroscopically in deflection of atomic beams in cavities or in reflection of atoms in atomic fountains. For a ground state, spherically symmetric atom the potential varies as -1/R 3 near the wall, where R is the atom-surface distance. For asymptotically large distances the potential is weaker and goes as -1/R 4 due to retardation arising from the finite speed of light. This diminished interaction can also be interpreted as a Casimir effect. The possibility of measuring atom-surface potentials using atomic interferometry is explored. The particular cases studied are the interactions of a ground-state alkali-metal atom and a dielectric or a conducting wall. Accurate descriptions of atom-surface potentials in theories of evanescent-wave atomic mirrors and evanescent wave-guided atoms are also discussed. (author)

  16. Surface potential measurement on contact resistance of amorphous-InGaZnO thin film transistors by Kelvin probe force microscopy

    Science.gov (United States)

    Han, Zhiheng; Xu, Guangwei; Wang, Wei; Lu, Congyan; Lu, Nianduan; Ji, Zhuoyu; Li, Ling; Liu, Ming

    2016-07-01

    Contact resistance plays an important role in amorphous InGaZnO (a-IGZO) thin film transistors (TFTs). In this paper, the surface potential distributions along the channel have been measured by using Kelvin probe force microscopy (KPFM) on operating a-IGZO TFTs, and sharp potential drops at the edges of source and drain were observed. The source and drain contact resistances can be extracted by dividing sharp potential drops with the corresponding drain to source current. It is found that the contact resistances could not be neglected compared with the whole channel resistances in the a-IGZO TFT, and the contact resistances decrease remarkably with increasing gate biased voltage. Our results suggest that the contact resistances can be controlled by tuning the gate biased voltage. Moreover, a transition from gradual channel approximation to space charge region was observed through the surface potential map directly when TFT operating from linear regime to saturation regime.

  17. Measurement of complex surfaces

    International Nuclear Information System (INIS)

    Brown, G.M.

    1993-05-01

    Several of the components used in coil fabrication involve complex surfaces and dimensions that are not well suited to measurements using conventional dimensional measuring equipment. Some relatively simple techniques that are in use in the SSCL Magnet Systems Division (MSD) for incoming inspection will be described, with discussion of their suitability for specific applications. Components that are submitted for MSD Quality Assurance (QA) dimensional inspection may be divided into two distinct categories; the first category involves components for which there is an approved drawing and for which all nominal dimensions are known; the second category involves parts for which 'reverse engineering' is required, the part is available but there are no available drawings or dimensions. This second category typically occurs during development of coil end parts and coil turn filler parts where it is necessary to manually shape the part and then measure it to develop the information required to prepare a drawing for the part

  18. Accurate surface potential determination in Schottky diodes by the use of a correlated current and capacitance voltage measurements. Application to n-InP

    International Nuclear Information System (INIS)

    Ahaitouf, Ali; Ahaitouf, Abdelaziz; Salvestrini, Jean Paul; Srour, Hussein

    2011-01-01

    Based on current voltage (I—V g ) and capacitance voltage (C—V g ) measurements, a reliable procedure is proposed to determine the effective surface potential V d (V g ) in Schottky diodes. In the framework of thermionic emission, our analysis includes both the effect of the series resistance and the ideality factor, even voltage dependent. This technique is applied to n-type indium phosphide (n-InP) Schottky diodes with and without an interfacial layer and allows us to provide an interpretation of the observed peak on the C—V g measurements. The study clearly shows that the depletion width and the flat band barrier height deduced from C—V g , which are important parameters directly related to the surface potential in the semiconductor, should be estimated within our approach to obtain more reliable information. (semiconductor devices)

  19. Scanning Surface Potential Microscopy of Spore Adhesion on Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ida [University of Tennessee, Knoxville (UTK); Chung, Eunhyea [Georgia Institute of Technology; Kweon, Hyojin [Georgia Institute of Technology; Yiacoumi, Sotira [Georgia Institute of Technology; Tsouris, Costas [ORNL

    2012-01-01

    The adhesion of spores of Bacillus anthracis - the cause of anthrax and a likely biological threat - to solid surfaces is an important consideration in cleanup after an accidental or deliberate release. However, because of safety concerns, directly studying B. anthracis spores with advanced instrumentation is problematic. As a first step, we are examining the electrostatic potential of Bacillus thuringiensis (Bt), which is a closely related species that is often used as a simulant to study B. anthracis. Scanning surface potential microscopy (SSPM), also known as Kelvin probe force microscopy (KPFM), was used to investigate the influence of relative humidity (RH) on the surface electrostatic potential of Bt that had adhered to silica, mica, or gold substrates. AFM/SSPM side-by-side images were obtained separately in air, at various values of RH, after an aqueous droplet with spores was applied on each surface and allowed to dry before measurements. In the SSPM images, a negative potential on the surface of the spores was observed compared with that of the substrates. The surface potential decreased as the humidity increased. Spores were unable to adhere to a surface with an extremely negative potential, such as mica.

  20. Measurement of surface roughness

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo

    This document is used in connection with two 3 hours laboratory exercises that are part of the course GEOMETRICAL METROLOGY AND MACHINE TESTING. The laboratories include a demonstration of the function of roughness measuring instruments plus a series of exercises illustrating roughness measurement...

  1. Armor Plate Surface Roughness Measurements

    National Research Council Canada - National Science Library

    Stanton, Brian; Coburn, William; Pizzillo, Thomas J

    2005-01-01

    ...., surface texture and coatings) that could become important at high frequency. We measure waviness and roughness of various plates to know the parameter range for smooth aluminum and rolled homogenous armor (RHA...

  2. Measurement of proton autoneutralization potential

    International Nuclear Information System (INIS)

    Garcia, M.

    1984-09-01

    A proton space charge having multi-MeV kinetic energy was injected through a thin ground plane to extract electrons and produce a time-dependent autoneutralization space potential. An electon-emitting floating-potential resistive divider was used to measure the space potential during 20 ns of the proton current pulse. During this time, proton kinetic energy fell from 10.6 MeV to 8.5 MeV and thus the space potential (taken as 1.09 x the floating potential) fell from 5.8 kV to 4.6 kV

  3. Artefacts for optical surface measurement

    Science.gov (United States)

    Robson, Stuart; Beraldin, J.-Angelo; Brownhill, Andrew; MacDonald, Lindsay

    2011-07-01

    Flexible manufacturing technologies are supporting the routine production of components with freeform surfaces in a wide variety of materials and surface finishes. Such surfaces may be exploited for both aesthetic and performance criteria for a wide range of industries, for example automotive, aircraft, small consumer goods and medial components. In order to ensure conformance between manufactured part and digital design it is necessary to understand, validate and promote best practice of the available measurement technologies. Similar, but currently less quantifiable, measurement requirements also exist in heritage, museum and fine art recording where objects can be individually hand crafted to extremely fine levels of detail. Optical 3D measurement systems designed for close range applications are typified by one or more illumination sources projecting a spot, line or structured light pattern onto a surface or surfaces of interest. Reflections from the projected light are detected in one or more imaging devices and measurements made concerning the location, intensity and optionally colour of the image. Coordinates of locations on the surface may be computed either directly from an understanding of the illumination and imaging geometry or indirectly through analysis of the spatial frequencies of the projected pattern. Regardless of sensing configuration some independent means is necessary to ensure that measurement capability will meet the requirements of a given level of object recording and is consistent for variations in surface properties and structure. As technologies mature, guidelines for best practice are emerging, most prominent at the current time being the German VDI/VDE 2634 and ISO/DIS 10360-8 guidelines. This considers state of the art capabilities for independent validation of optical non-contact measurement systems suited to the close range measurement of table top sized manufactured or crafted objects.

  4. Potential measurements in tandem mirrors

    International Nuclear Information System (INIS)

    Glowienka, J.C.

    1985-11-01

    The US mirror program has begun conducting experiments with a thermal barrier tandem mirror configuration. This configuration requires a specific axial potential profile and implies measurements of potential for documentation and optimization of the configuration. This report briefly outlines the motivation for the thermal barrier tandem mirror and then outlines the techniques used to document the potential profile in conventional and thermal barrier tandem mirrors. Examples of typical data sets from the world's major tandem mirror experiments, TMX and TMX-U at Lawrence Livermore National Laboratory (LLNL) and Gamma 10 at Tsukuba University in Japan, and the current interpretation of the data are discussed together with plans for the future improvement of measurements of plasma potential

  5. Computer simulation of pitting potential measurements

    International Nuclear Information System (INIS)

    Laycock, N.J.; Noh, J.S.; White, S.P.; Krouse, D.P.

    2005-01-01

    A deterministic model for the growth of single pits in stainless steel has been combined with a purely stochastic model of pit nucleation. Monte-Carlo simulations have been used to compare the predictions of this model with potentiodynamic experimental measurements of the pitting potential. The quantitative agreement between model and experiment is reasonable for both 304 and 316 stainless steel, and the effects of varying surface roughness, solution chloride concentration and potential sweep rate have been considered

  6. Surface flow measurements from drones

    Science.gov (United States)

    Tauro, Flavia; Porfiri, Maurizio; Grimaldi, Salvatore

    2016-09-01

    Drones are transforming the way we sense and interact with the environment. However, despite their increased capabilities, the use of drones in geophysical sciences usually focuses on image acquisition for generating high-resolution maps. Motivated by the increasing demand for innovative and high performance geophysical observational methodologies, we posit the integration of drone technology and optical sensing toward a quantitative characterization of surface flow phenomena. We demonstrate that a recreational drone can be used to yield accurate surface flow maps of sub-meter water bodies. Specifically, drone's vibrations do not hinder surface flow observations, and velocity measurements are in agreement with traditional techniques. This first instance of quantitative water flow sensing from a flying drone paves the way to novel observations of the environment.

  7. Streaming potential measurements of biosurfaces

    Science.gov (United States)

    Van Wagenen, R. A.; Andrade, J. D.; Hibbs, J. B., Jr.

    1976-01-01

    A technique based on the measurement of streaming potentials has been developed to evaluate the electrokinetic region of the cell periphery. This approach is feasible for cell lines propagated in in-vitro cell cultures in monolayer form. The advantage of this system is that cells may be evaluated in the living state atttached to a substrate; it is not necessary to subject the cells to enzymatic, chemical, or mechanical trauma required to obtain monodisperse suspensions which are then normally evaluated by microelectrophoresis. In this manner, it should be possible to study the influence of substrate and environmental factors on the charge density and potential at the cell periphery. The apparatus and procedure are described as well as some results concerning the electrokinetic potential of borosilicate capillaries as a function of ionic strength, pH, and temperature. The effect that turbulence and entrance flow conditions have on accurate streaming-potential measurements is discussed. The electrokinetic potential of BALB/c 3T12 fibroblasts has been quantified as a function of pH, ionic strength, glutaraldehyde fixation, and Giemsa staining.

  8. Method of measuring surface density

    International Nuclear Information System (INIS)

    Gregor, J.

    1982-01-01

    A method is described of measuring surface density or thickness, preferably of coating layers, using radiation emitted by a suitable radionuclide, e.g., 241 Am. The radiation impinges on the measured material, e.g., a copper foil and in dependence on its surface density or thickness part of the flux of impinging radiation is reflected and part penetrates through the material. The radiation which has penetrated through the material excites in a replaceable adjustable backing characteristic radiation of an energy close to that of the impinging radiation (within +-30 keV). Part of the flux of the characteristic radiation spreads back to the detector, penetrates through the material in which in dependence on surface density or thickness of the coating layer it is partly absorbed. The flux of the penetrated characteristic radiation impinging on the face of the detector is a function of surface density or thickness. Only that part of the energy is evaluated of the energy spectrum which corresponds to the energy of characteristic radiation. (B.S.)

  9. Optical measurements on contaminated surfaces

    Science.gov (United States)

    Bonham, T. E.; Schmitt, R. J.; Linford, R. M. F.

    1975-01-01

    A bidirectional reflectometer system was developed for in situ measurements of the changes in spectral reflectance of surfaces contaminated with films of organic materials. The system permits experiments with films of controlled thickness in an environment that simulates the thermal, radiation, and vacuum conditions of space. The mechanical and optical construction of the reflectometer are discussed in detail, and actual data curves are used to illustrate its operation and performance.

  10. Surface Potential of Polycrystalline Hematite in Aqueous Medium

    Directory of Open Access Journals (Sweden)

    Tajana Preočanin

    2011-01-01

    Full Text Available The surface potential of polycrystalline hematite in aqueous sodium perchlorate environment as a function of pH was examined. Surface potential of hematite was obtained from measured electrode potential of a nonporous polycrystalline hematite electrode. Acidic solution was titrated with base, and the backward titration with acid was performed. Substantial hysteresis was obtained which enabled location of the point of zero potential and equilibrium values of surface potentials. The theoretical interpretation of the equilibrium data was performed by applying the surface complexation model and the thermodynamic equilibrium constants for the first and the second step of surface protonation was obtained as logK1∘=11.3;logK2∘=2.8.

  11. Wettability Studies Using Zeta Potential Measurements

    Directory of Open Access Journals (Sweden)

    Ghada Bassioni

    2015-01-01

    Full Text Available Wettability studies have been carried out on reservoir rocks using different techniques such as the Amott-Harvey method, the USBM method, and the contact angle method, all with limitations. In this study, the wettability is studied by discussing the surface charge using zeta potential measurements. The study relies on the finding that carbonated reservoir rocks, consisting of CaCO3 mainly, are positively charged and their surface has the potential to adsorb significant quantities of anions. Moreover, heavy fractions such as asphaltenes are reported to remain afloat depending on dispersive forces present in the oil and its various fractions. Experiments are carried out on aqueous limestone suspension with the addition of crude oil. The experiment is repeated with the use of polymeric inhibitors, A and B. The zeta potential is found to alter depending on the sequence of polymeric inhibitor in oil/water addition. The inhibitor is found to adsorb on the limestone surface, with a net negative charge, causing repulsion between crude oil and the inhibitor and, hence, preventing the deposition of heavy fractions and particularly asphaltenes. This study gives a comprehensive insight on the mechanism of polymeric inhibitor interaction with the surface and the effect of wettability on its performance.

  12. Potential energy surface of alanine polypeptide chains

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Yakubovich, Alexander V.; Solov'yov, Andrey V.

    2006-01-01

    The multidimensional potential energy surfaces of the peptide chains consisting of three and six alanine (Ala) residues have been studied with respect to the degrees of freedom related to the twist of these molecules relative to the peptide backbone (these degrees of freedom are responsible...

  13. Probing Anisotropic Surface Properties of Molybdenite by Direct Force Measurements.

    Science.gov (United States)

    Lu, Zhenzhen; Liu, Qingxia; Xu, Zhenghe; Zeng, Hongbo

    2015-10-27

    Probing anisotropic surface properties of layer-type mineral is fundamentally important in understanding its surface charge and wettability for a variety of applications. In this study, the surface properties of the face and the edge surfaces of natural molybdenite (MoS2) were investigated by direct surface force measurements using atomic force microscope (AFM). The interaction forces between the AFM tip (Si3N4) and face or edge surface of molybdenite were measured in 10 mM NaCl solutions at various pHs. The force profiles were well-fitted with classical DLVO (Derjaguin-Landau-Verwey-Overbeek) theory to determine the surface potentials of the face and the edge surfaces of molybdenite. The surface potentials of both the face and edge surfaces become more negative with increasing pH. At neutral and alkaline conditions, the edge surface exhibits more negative surface potential than the face surface, which is possibly due to molybdate and hydromolybdate ions on the edge surface. The point of zero charge (PZC) of the edge surface was determined around pH 3 while PZC of the face surface was not observed in the range of pH 3-11. The interaction forces between octadecyltrichlorosilane-treated AFM tip (OTS-tip) and face or edge surface of molybdenite were also measured at various pHs to study the wettability of molybdenite surfaces. An attractive force between the OTS-tip and the face surface was detected. The force profiles were well-fitted by considering DLVO forces and additional hydrophobic force. Our results suggest the hydrophobic feature of the face surface of molybdenite. In contrast, no attractive force between the OTS-tip and the edge surface was detected. This is the first study in directly measuring surface charge and wettability of the pristine face and edge surfaces of molybdenite through surface force measurements.

  14. Effects on humans elicited by inhaling the fragrance of essential oils: sensory test, multi-channel thermometric study and forehead surface potential wave measurement on basil and peppermint.

    Science.gov (United States)

    Satoh, Tomoko; Sugawara, Yoshiaki

    2003-01-01

    The effects on humans inhaling the fragrance of essential oils were examined in terms of a sensory test, a multi-channel skin thermometer study and a portable forehead surface electroencephalographic (IBVA-EEG) measurement. The essential oils examined in this study were those of basil and peppermint, because our previous sensory test had indicated an opposite effect of these essential oils when mental work was undertaken; the inhalation of basil produced a more favorable impression after work than before work, whereas peppermint produced an unfavorable impression under these circumstances. For subjects administered basil or peppermint before and after mental work using an inhalator, a series of multi-channel skin thermometer studies and IBVA-EEG measurements were conducted. Using such paired odorants, our results showed that when compared between before and after mental work assigned to subjects: (1) the inhalation of basil, in which a favorable impression was predominant on the whole in terms of the sensory evaluation spectrum, was shown to be associated upward tendency in finger-tip skin temperature; (2) whereas these situations were opposite in the case of peppermint, in which the reversed (unfavorable) feature in sensory profiling was accompanied by a decrease in the magnitude of beta waves and a decrease in the finger-tip skin temperature both based on Welch's method, even at p < 0.01, implying a decreasing propensity of the aroused state and of the arousal response. The elucidation of such sensory and physiological endpoints of paired odorants would be of primary importance for human chemoreception science, because these are only rarely recorded during the same experiments, and this paradigm is highly informative about non-verbal responses to odorants.

  15. Surface potential domains on lamellar P3OT structures

    Energy Technology Data Exchange (ETDEWEB)

    Perez-GarcIa, B [Departamento Fisica, Facultad de Quimica (Campus Espinardo), Universidad de Murcia, E-30100 Murcia (Spain); Abad, J [Departamento Fisica, Facultad de Quimica (Campus Espinardo), Universidad de Murcia, E-30100 Murcia (Spain); Urbina, A [Departamento Electronica, TecnologIa de Computadoras y Proyectos, Universidad Politecnica de Cartagena, E-30202 Cartagena (Spain); Colchero, J [Departamento Fisica, Facultad de Quimica (Campus Espinardo), Universidad de Murcia, E-30100 Murcia (Spain); Palacios-Lidon, E [Departamento Fisica, Facultad de Quimica (Campus Espinardo), Universidad de Murcia, E-30100 Murcia (Spain)

    2008-02-13

    In this work the electrostatic properties of poly(3-octylthiophene) thin films have been studied on a nanometer scale by means of electrostatic force microscopy and Kelvin probe microscopy (KPM). The KPM images reveal that different surface contact potential domains coexist on the polymer surface. This result, together with additional capacitance measurements, indicates that the potential domains are related to the existence of dipoles due to different molecular arrangements. Finally, capacitance measurements as a function of the tip-sample bias voltage show that in all regions large band bending effects take place.

  16. Surface potential domains on lamellar P3OT structures

    International Nuclear Information System (INIS)

    Perez-GarcIa, B; Abad, J; Urbina, A; Colchero, J; Palacios-Lidon, E

    2008-01-01

    In this work the electrostatic properties of poly(3-octylthiophene) thin films have been studied on a nanometer scale by means of electrostatic force microscopy and Kelvin probe microscopy (KPM). The KPM images reveal that different surface contact potential domains coexist on the polymer surface. This result, together with additional capacitance measurements, indicates that the potential domains are related to the existence of dipoles due to different molecular arrangements. Finally, capacitance measurements as a function of the tip-sample bias voltage show that in all regions large band bending effects take place

  17. Potential energy surfaces for nucleon exchanging in dinuclear systems

    International Nuclear Information System (INIS)

    Li Jianfeng; Xu Hushan; Li Wenfei; Zuo Wei; Li Junqing; Wang Nan; Zhao Enguang

    2003-01-01

    The experimental measurements have provided the evidence that the suppression of fusion cross-section caused by quasi-fission is very important for the synthesis of super-heavy nuclei by heavy ion collisions. The potential energy surface due to the nucleon transfer in the collision process is the driven potential, which governs the nucleon transfer, so that governs the competition between the fusion and quasi-fission. The dinuclear system potential energy surface also gives the information about the optimum projectile-target combination, as well as the optimum excitation energy for the synthesis of super-heavy nuclei by heavy ion collisions

  18. The measurement of surface gravity.

    Science.gov (United States)

    Crossley, David; Hinderer, Jacques; Riccardi, Umberto

    2013-04-01

    This review covers basic theory and techniques behind the use of ground-based gravimetry at the Earth's surface. The orientation is toward modern instrumentation, data processing and interpretation for observing surface, land-based, time-variable changes to the geopotential. The instrumentation side is covered in some detail, with specifications and performance of the most widely used models of the three main types: the absolute gravimeters (FG5, A10 from Micro-g LaCoste), superconducting gravimeters (OSG, iGrav from GWR instruments), and the new generation of spring instruments (Micro-g LaCoste gPhone, Scintrex CG5 and Burris ZLS). A wide range of applications is covered, with selected examples from tides and ocean loading, atmospheric effects on gravity, local and global hydrology, seismology and normal modes, long period and tectonics, volcanology, exploration gravimetry, and some examples of gravimetry connected to fundamental physics. We show that there are only a modest number of very large signals, i.e. hundreds of µGal (10(-8) m s(-2)), that are easy to see with all gravimeters (e.g. tides, volcanic eruptions, large earthquakes, seasonal hydrology). The majority of signals of interest are in the range 0.1-5.0 µGal and occur at a wide range of time scales (minutes to years) and spatial extent (a few meters to global). Here the competing effects require a careful combination of different gravimeter types and measurement strategies to efficiently characterize and distinguish the signals. Gravimeters are sophisticated instruments, with substantial up-front costs, and they place demands on the operators to maximize the results. Nevertheless their performance characteristics such as drift and precision have improved dramatically in recent years, and their data recording ability and ruggedness have seen similar advances. Many subtle signals are now routinely connected with known geophysical effects such as coseismic earthquake displacements, post

  19. Soil and gas and radon entry potentials for substructure surfaces

    International Nuclear Information System (INIS)

    Harrison, J.; Sextro, R.G.

    1990-01-01

    This paper reports on measurement techniques and parameters that describe the potential for areas of a building substructure to have high soil gas and radon entry rates which have been developed. Flows and pressures measured at test holes in substructure surfaces while the substructure was intentionally depressurized were used in a highly simplified electrical circuit to model the substructure/soil network. Data from four New Jersey houses indicate that the soil was a factor of two to six times more resistant to soil gas flow than substructure surfaces, concrete slab floors, including perimeter gaps, cracks, and other penetrations, were approximately five times more resistant to soil gas movement than hollow block walls, and radon entry potentials were highest for slab floors. These indices of entry potential may be useful for characterizing the relative leakiness of below-grade substructure surfaces and for determining the selection and placement of radon control systems

  20. Theoretical studies of potential energy surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Harding, L.B. [Argonne National Laboratory, IL (United States)

    1993-12-01

    The goal of this program is to calculate accurate potential energy surfaces (PES) for both reactive and nonreactive systems. To do this the electronic Schrodinger equation must be solved. Our approach to this problem starts with multiconfiguration self-consistent field (MCSCF) reference wavefunctions. These reference wavefunctions are designed to be sufficiently flexible to accurately describe changes in electronic structure over a broad range of geometries. Electron correlation effects are included via multireference, singles and doubles configuration interaction (MRSDCI) calculations. With this approach, the authors are able to provide useful predictions of the energetics for a broad range of systems.

  1. Behaviour of a surface EMG based measure for motor control: Motor unit action potential rate in relation to force and muscle fatigue

    NARCIS (Netherlands)

    Kallenberg, L.A.C.; Hermens, Hermanus J.

    2008-01-01

    Surface electromyography parameters such as root-mean-square value (RMS) and median power frequency (FMED) are commonly used to assess the input of the central nervous system (CNS) to a muscle. However, RMS and FMED are influenced not only by CNS input, but also by peripheral muscle properties. The

  2. Comparative Measurement of Microcystins in Diverse Surface ...

    Science.gov (United States)

    The measurement of microcystins, cyanotoxins associated with cyanobacterial blooms which are increasingly prevalent in inland waters, is complicated by the diversity of congeners which have been observed in the environment. At present, more than 150 microcystin congeners have been identified, and this poses a significant challenge to analytical methods intended to assess human health risks in surface and drinking water systems. The most widely employed analytical method at present is the ADDA-ELISA technique which is potentially sensitive to all microcystins, but it is primarily intended as a semi-quantitative method, and questions have been raised regarding the potential for cross-reactivity and false positives. LC-MS/MS methods targeting specific congeners, such as US EPA Method 544, are intended for use as a secondary confirmation following a positive ELISA response, but these techniques can target only those congeners for which commercial standards are available. Accordingly, they are not suitable for ascertaining the safety of a given water sample, given the potential for omitting unknown microcystin congeners which might be present.An alternative approach involves oxidative transformation of microcystins to a common product, 2-methyl-3-methoxy-4-phenylbutyric acid, or MMPB. Measuring MMPB by LC-MS/MS can potentially provide a metric for the sum of all microcystin congeners present in a sample, subject to the efficiency and overall yield of conversion. The

  3. Revealing the effect of electrode materials on the performance of low-voltage pentacene thin film transistor by in-situ surface potential measurement

    International Nuclear Information System (INIS)

    Chen, Q L; Liu, Q C; Jin, H Y; Ouyang, M; Xie, W G

    2015-01-01

    We investigate the effect of contact potential between Au, CuO x and Au-CuO x , and pentacene thin films by Kevin Probe microscopy Compared to the Au contact, although the injection barrier is lower for CuO x contact, the extraction barrier is higher, and the total contact resistance is only slightly smaller. The better performance of CuO x contact device results from the doping effect from the p-type CuO x . The introduction of additional Au top layer deposited on the thin CuO x layer lowersthe extraction barrier and facilitates better carrier transfer, which further reduces the contact resistance. Therefore, both the apparent mobility and channel mobility are the best in the device with Au-CuO x double layer contact. (paper)

  4. Energy conservation potential of surface modification technologies

    Energy Technology Data Exchange (ETDEWEB)

    Le, H.K.; Horne, D.M.; Silberglitt, R.S.

    1985-09-01

    This report assesses the energy conservation impact of surface modification technologies on the metalworking industries. The energy conservation impact of surface modification technologies on the metalworking industries is assessed by estimating their friction and wear tribological sinks and the subsequent reduction in these sinks when surface modified tools are used. Ion implantation, coatings, and laser and electron beam surface modifications are considered.

  5. Contact area measurements on structured surfaces

    DEFF Research Database (Denmark)

    Kücükyildiz, Ömer Can; Jensen, Sebastian Hoppe Nesgaard; De Chiffre, Leonardo

    In connection with the use of brass specimens featuring structured surfaces in a tribology test, an algorithm was developed for automatic measurement of the contact area by optical means.......In connection with the use of brass specimens featuring structured surfaces in a tribology test, an algorithm was developed for automatic measurement of the contact area by optical means....

  6. Aspheric surface measurement using capacitive probes

    Science.gov (United States)

    Tao, Xin; Yuan, Daocheng; Li, Shaobo

    2017-02-01

    With the application of aspheres in optical fields, high precision and high efficiency aspheric surface metrology becomes a hot research topic. We describe a novel method of non-contact measurement of aspheric surface with capacitive probe. Taking an eccentric spherical surface as the object of study, the averaging effect of capacitive probe measurement and the influence of tilting the capacitive probe on the measurement results are investigated. By comparing measurement results from simultaneous measurement of the capacitive probe and contact probe of roundness instrument, this paper indicates the feasibility of using capacitive probes to test aspheric surface and proposes the compensation method of measurement error caused by averaging effect and the tilting of the capacitive probe.

  7. Computed potential energy surfaces for chemical reactions

    Science.gov (United States)

    Walch, Stephen P.

    1988-01-01

    The minimum energy path for the addition of a hydrogen atom to N2 is characterized in CASSCF/CCI calculations using the (4s3p2d1f/3s2p1d) basis set, with additional single point calculations at the stationary points of the potential energy surface using the (5s4p3d2f/4s3p2d) basis set. These calculations represent the most extensive set of ab initio calculations completed to date, yielding a zero point corrected barrier for HN2 dissociation of approx. 8.5 kcal mol/1. The lifetime of the HN2 species is estimated from the calculated geometries and energetics using both conventional Transition State Theory and a method which utilizes an Eckart barrier to compute one dimensional quantum mechanical tunneling effects. It is concluded that the lifetime of the HN2 species is very short, greatly limiting its role in both termolecular recombination reactions and combustion processes.

  8. Surface texture measurement for dental wear applications

    Science.gov (United States)

    Austin, R. S.; Mullen, F.; Bartlett, D. W.

    2015-06-01

    The application of surface topography measurement and characterization within dental materials science is highly active and rapidly developing, in line with many modern industries. Surface measurement and structuring is used extensively within oral and dental science to optimize the optical, tribological and biological performance of natural and biomimetic dental materials. Although there has historically been little standardization in the use and reporting of surface metrology instrumentation and software, the dental industry is beginning to adopt modern areal measurement and characterization techniques, especially as the dental industry is increasingly adopting digital impressioning techniques in order to leverage CAD/CAM technologies for the design and construction of dental restorations. As dental treatment becomes increasingly digitized and reliant on advanced technologies such as dental implants, wider adoption of standardized surface topography and characterization techniques will become evermore essential. The dental research community welcomes the advances that are being made in surface topography measurement science towards realizing this ultimate goal.

  9. Surface texture measurement for additive manufacturing

    Science.gov (United States)

    Triantaphyllou, Andrew; Giusca, Claudiu L.; Macaulay, Gavin D.; Roerig, Felix; Hoebel, Matthias; Leach, Richard K.; Tomita, Ben; Milne, Katherine A.

    2015-06-01

    The surface texture of additively manufactured metallic surfaces made by powder bed methods is affected by a number of factors, including the powder’s particle size distribution, the effect of the heat source, the thickness of the printed layers, the angle of the surface relative to the horizontal build bed and the effect of any post processing/finishing. The aim of the research reported here is to understand the way these surfaces should be measured in order to characterise them. In published research to date, the surface texture is generally reported as an Ra value, measured across the lay. The appropriateness of this method for such surfaces is investigated here. A preliminary investigation was carried out on two additive manufacturing processes—selective laser melting (SLM) and electron beam melting (EBM)—focusing on the effect of build angle and post processing. The surfaces were measured using both tactile and optical methods and a range of profile and areal parameters were reported. Test coupons were manufactured at four angles relative to the horizontal plane of the powder bed using both SLM and EBM. The effect of lay—caused by the layered nature of the manufacturing process—was investigated, as was the required sample area for optical measurements. The surfaces were also measured before and after grit blasting.

  10. Surface texture measurement for additive manufacturing

    International Nuclear Information System (INIS)

    Triantaphyllou, Andrew; Tomita, Ben; Milne, Katherine A; Giusca, Claudiu L; Macaulay, Gavin D; Roerig, Felix; Hoebel, Matthias; Leach, Richard K

    2015-01-01

    The surface texture of additively manufactured metallic surfaces made by powder bed methods is affected by a number of factors, including the powder’s particle size distribution, the effect of the heat source, the thickness of the printed layers, the angle of the surface relative to the horizontal build bed and the effect of any post processing/finishing. The aim of the research reported here is to understand the way these surfaces should be measured in order to characterise them. In published research to date, the surface texture is generally reported as an Ra value, measured across the lay. The appropriateness of this method for such surfaces is investigated here. A preliminary investigation was carried out on two additive manufacturing processes—selective laser melting (SLM) and electron beam melting (EBM)—focusing on the effect of build angle and post processing. The surfaces were measured using both tactile and optical methods and a range of profile and areal parameters were reported. Test coupons were manufactured at four angles relative to the horizontal plane of the powder bed using both SLM and EBM. The effect of lay—caused by the layered nature of the manufacturing process—was investigated, as was the required sample area for optical measurements. The surfaces were also measured before and after grit blasting. (paper)

  11. Measuring Light Reflectance of BGO Crystal Surfaces

    Science.gov (United States)

    Janecek, Martin; Moses, William W.

    2008-10-01

    A scintillating crystal's surface reflectance has to be well understood in order to accurately predict and optimize the crystal's light collection through Monte Carlo simulations. In this paper, we measure the inner surface reflectance properties for BGO. The measurements include BGO crystals with a mechanically polished surface, rough-cut surface, and chemically etched surface, and with various reflectors attached, both air-coupled and with coupling compound. The measurements are performed with a laser aimed at the center of a hemispherical shaped BGO crystal. The hemispherical shape eliminates any non-perpendicular angles for light entering and exiting the crystal. The reflected light is collected with an array of photodiodes. The laser can be set at an arbitrary angle, and the photodiode array is rotated to fully cover 2pi of solid angle. The current produced in the photodiodes is readout with a digital multimeter connected through a multiplexer. The two rows of photodiodes achieve 5-degree by 4-degree resolution, and the current measurement has a dynamic range of 105:1. The acquired data was not described by the commonly assumed linear combination of specular and diffuse (Lambertian) distributions, except for a very few surfaces. Surface roughness proved to be the most important parameter when choosing crystal setup. The reflector choice was of less importance and of almost no consequence for rough-cut surfaces. Pure specular reflection distribution for all incidence angles was measured for polished surfaces with VM2000 film, while the most Lambertian distribution for any surface finish was measured for titanium dioxide paint. The distributions acquired in this paper will be used to create more accurate Monte Carlo models for light reflection distribution within BGO crystals.

  12. Geometric Measure Theory and Minimal Surfaces

    CERN Document Server

    Bombieri, Enrico

    2011-01-01

    W.K. ALLARD: On the first variation of area and generalized mean curvature.- F.J. ALMGREN Jr.: Geometric measure theory and elliptic variational problems.- E. GIUSTI: Minimal surfaces with obstacles.- J. GUCKENHEIMER: Singularities in soap-bubble-like and soap-film-like surfaces.- D. KINDERLEHRER: The analyticity of the coincidence set in variational inequalities.- M. MIRANDA: Boundaries of Caciopoli sets in the calculus of variations.- L. PICCININI: De Giorgi's measure and thin obstacles.

  13. Four-point potential drop measurements for materials characterization

    International Nuclear Information System (INIS)

    Bowler, Nicola

    2011-01-01

    The technique of measuring the voltage difference (potential drop) between two of the four electrodes of a four-point probe, in order to determine conductivity or surface resistivity of a test piece, is well established in the direct-current (dc) or quasi-dc regime. The technique finds wide usage in the semiconductor industry for the purpose of measuring surface resistivity of semiconductors, and also in the measurement of conductivity of metals, particularly of ferromagnetic metals for which conductivity cannot be easily measured using eddy-current nondestructive evaluation (NDE). In these applications, the conductivity of the test piece is deduced from an analytic formula that depends on the geometry of the probe and test piece. Such a formula requires, as an input, the measured value of the potential drop. Several analytical expressions exist for a variety of test-piece geometries and probe arrangements. Recently, it has been shown that broadband measurements of the potential drop, known as 'alternating current potential drop' (ac PD) measurements, can be used not only to obtain the conductivity of a test piece, but also its linear permeability μ. The beauty of this measurement is that the two parameters are completely decoupled in the quasi-static regime. In fact, μ does not appear in the quasi-static expression for σ. Hence, σ may be obtained from low-frequency ac PD measurements and then μ may be deduced as the frequency increases beyond the quasi-static regime, once σ is known. In this review, both dc and ac solutions that are useful in determining the conductivity of metals and semiconductors, and the permeability of ferromagnetic conductors, are summarized. In particular, flat test pieces with arbitrary thickness are considered. At the next level of complexity, a solution for a half-space coated with a surface layer is given, along with a discussion of the use of the four-point potential drop method for determining thickness of a surface layer, such

  14. Measurement of human potential in organizations

    Directory of Open Access Journals (Sweden)

    Rosa María Fuchs Ángeles

    2015-09-01

    Full Text Available Companies around the world are concerned about talent management in their organizations. The concern is to retain talented employees and this may not be possible if they are not properly identified. Performance and potential evaluations become then important. Performance evaluations qualify the historical record of the employee, so their measurement is provided. However, measuring the potential performance assesses potential future charges, therefore it is not a simple task. In this paper, characteristics evaluated in potential employees and tools that are commonly used are presented. Also, the case of four companies operating in Peru is shown.

  15. Sound field separation with cross measurement surfaces.

    Directory of Open Access Journals (Sweden)

    Jin Mao

    Full Text Available With conventional near-field acoustical holography, it is impossible to identify sound pressure when the coherent sound sources are located on the same side of the array. This paper proposes a solution, using cross measurement surfaces to separate the sources based on the equivalent source method. Each equivalent source surface is built in the center of the corresponding original source with a spherical surface. According to the different transfer matrices between equivalent sources and points on holographic surfaces, the weighting of each equivalent source from coherent sources can be obtained. Numerical and experimental studies have been performed to test the method. For the sound pressure including noise after separation in the experiment, the calculation accuracy can be improved by reconstructing the pressure with Tikhonov regularization and the L-curve method. On the whole, a single source can be effectively separated from coherent sources using cross measurement.

  16. Nuclear momentum distribution and potential energy surface in hexagonal ice

    Science.gov (United States)

    Lin, Lin; Morrone, Joseph; Car, Roberto; Parrinello, Michele

    2011-03-01

    The proton momentum distribution in ice Ih has been recently measured by deep inelastic neutron scattering and calculated from open path integral Car-Parrinello simulation. Here we report a detailed investigation of the relation between momentum distribution and potential energy surface based on both experiment and simulation results. The potential experienced by the proton is largely harmonic and characterized by 3 principal frequencies, which can be associated to weighted averages of phonon frequencies via lattice dynamics calculations. This approach also allows us to examine the importance of quantum effects on the dynamics of the oxygen nuclei close to the melting temperature. Finally we quantify the anharmonicity that is present in the potential acting on the protons. This work is supported by NSF and by DOE.

  17. Potential measurement and radial transport in GAMMA 10 tandem mirror

    International Nuclear Information System (INIS)

    Ishii, K.; Katanuma, I.; Segawa, T.; Ohkawara, H.; Mase, A.; Miyoshi, S.

    1989-01-01

    GAMMA 10 is an effectively axisymmetric tandem mirror with thermal barriers. Potential information is important to investigate the plasma confinement. The barrier and central space potentials are determined by means of two gold neutral beam probes. Two-dimensional potential profiles have been measured in the barrier cell. In GAMMA 10, to assure magneto-hydrodynamic (MHD) stability, the nonaxisymmetric minimum-B mirror cells are contained between the central-solenoid and the plug/barrier cells at the ends of the machine. From the point of view of neoclassical resonant-plateau transport in circular equipotential contours, this effective axisymmetrization is successful. The measured potential profiles are slightly elongated during the onset of ω ce ECRH. In this paper we report the beam probe potential measurement, the neoclassical ion radial transport in the noncircular equipotential surface and the thermal barrier potential. (author) 6 refs., 5 figs

  18. Open questions in surface topography measurement: a roadmap

    International Nuclear Information System (INIS)

    Leach, Richard; Evans, Christopher; He, Liangyu; Davies, Angela; Duparré, Angela; Henning, Andrew; Jones, Christopher W; O’Connor, Daniel

    2015-01-01

    Control of surface topography has always been of vital importance for manufacturing and many other engineering and scientific disciplines. However, despite over one hundred years of quantitative surface topography measurement, there are still many open questions. At the top of the list of questions is ‘Are we getting the right answer?’ This begs the obvious question ‘How would we know?’ There are many other questions relating to applications, the appropriateness of a technique for a given scenario, or the relationship between a particular analysis and the function of the surface. In this first ‘open questions’ article we have gathered together some experts in surface topography measurement and asked them to address timely, unresolved questions about the subject. We hope that their responses will go some way to answer these questions, address areas where further research is required, and look at the future of the subject. The first section ‘Spatial content characterization for precision surfaces’ addresses the need to characterise the spatial content of precision surfaces. Whilst we have been manufacturing optics for centuries, there still isn’t a consensus on how to specify the surface for manufacture. The most common three methods for spatial characterisation are reviewed and compared, and the need for further work on quantifying measurement uncertainties is highlighted. The article is focussed on optical surfaces, but the ideas are more pervasive. Different communities refer to ‘figure, mid-spatial frequencies, and finish’ and ‘form, waviness, and roughness’, but the mathematics are identical. The second section ‘Light scattering methods’ is focussed on light scattering techniques; an important topic with in-line metrology becoming essential in many manufacturing scenarios. The potential of scattering methods has long been recognized; in the ‘smooth surface limit’ functionally significant relationships can be derived from first

  19. Surface resistivity measurement of plasma treated polymers

    International Nuclear Information System (INIS)

    Simon, D.; Pigram, P.J.; Liesegang, J.

    2000-01-01

    Full text: Resistivity of insulators is an important property of materials used within the integrated circuit and packaging industries. The measurement of electrical resistivity of insulator materials in the surface region in this work is interpreted through observations of surface charge decay. A self-field driven and diffusion charge transport theory is used to model the process and resistivity values obtained computationally. Data for the charge decay of surface charged samples are collected by suspending them inside a coaxial cylinder connected to an electrometer. Samples used have been low density polyethylene LDPE sheet, both pristine and surface treated. Some samples have been treated by air plasma at low vacuum pressures for different periods of time; others have been washed in ethyl acetate and then plasma treated before the resistivity measurement. The sets of resistivity measurements form the various treatments are compared below. X-ray photoelectron spectroscopy (XPS) has also been used to investigate and account for the observed variations in surface resistivity

  20. Measurement of gastrointestinal transmural electric potential difference in man.

    Science.gov (United States)

    Geall, M G; Code, C F; McIlrath, D C; Summerskill, W H

    1970-01-01

    Measurement, in man, of the electric potential difference between venous blood and the mucosal surface of the gastrointestinal tract gave identical values to the potential difference between mucosa and serosa. Various parts of the peritoneum were equipotential with venous blood. By contrast, skin-enteric potential difference varied with time and among different subjects because of a potential difference between skin and blood that is unpredictably reduced by skin injury. The results with electrolyte bridges of KCl in agar or of flowing KCl were identical.

  1. Surface Tension Measurements with a Smartphone

    Science.gov (United States)

    Goy, Nicolas-Alexandre; Denis, Zakari; Lavaud, Maxime; Grolleau, Adrian; Dufour, Nicolas; Deblais, Antoine; Delabre, Ulysse

    2017-01-01

    Smartphones are increasingly used in higher education and at university in mechanics, acoustics, and even thermodynamics as they offer a unique way to do simple science experiments. In this article, we show how smartphones can be used in fluid mechanics to measure surface tension of various liquids, which could help students understand the concept…

  2. Surface charge measurement using an electrostatic probe

    DEFF Research Database (Denmark)

    Crichton, George C; McAllister, Iain Wilson

    1998-01-01

    During the 1960s, the first measurements of charge on dielectric surfaces using simple electrostatic probes were reported. However it is only within the last 10 years that a proper understanding of the probe response has been developed. This situation arose as a consequence of the earlier studies...

  3. Optical measurement of surface roughness in manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Brodmann, R.

    1984-11-01

    The measuring system described here is based on the light-scattering method, and was developed by Optische Werke G. Rodenstock, Munich. It is especially useful for rapid non-contact monitoring of surface roughness in production-related areas. This paper outlines the differences between this system and the common stylus instrument, including descriptions of some applications in industry.

  4. Effect of surface roughness and surface modification of indium tin oxide electrode on its potential response to tryptophan

    International Nuclear Information System (INIS)

    Khan, Md. Zaved Hossain; Nakanishi, Takuya; Kuroiwa, Shigeki; Hoshi, Yoichi; Osaka, Tetsuya

    2011-01-01

    Highlights: → We examine factors affecting potential response of ITO electrode to tryptophan. → Surface roughness of ITO electrode affects the stability of its rest potential. → Surface modification is effective for ITO electrode with a certain roughness. → Optimum values of work function exist for potential response of ITO to tryptophan. - Abstract: The effect of surface modification of indium tin oxide (ITO) electrode on its potential response to tryptophan was investigated for ITO substrates with different surface roughness. It was found that a small difference in surface roughness, between ∼1 and ∼2 nm of R a evaluated by atomic force microscopy, affects the rest potential of ITO electrode in the electrolyte. A slight difference in In:Sn ratio at the near surface of the ITO substrates, measured by angle-resolved X-ray photoelectron spectrometry and Auger electron spectroscopy is remarkable, and considered to relate with surface roughness. Interestingly, successive modification of the ITO surface with aminopropylsilane and disuccinimidyl suberate, of which essentiality to the potential response to indole compounds we previously reported, improved the stability of the rest potential and enabled the electrodes to respond to tryptophan in case of specimens with R a values ranging between ∼2 and ∼3 nm but not for those with R a of ∼1 nm. It was suggested that there are optimum values of effective work function of ITO for specific potential response to tryptophan, which can be obtained by the successive modification of ITO surface.

  5. Surface dose extrapolation measurements with radiographic film

    International Nuclear Information System (INIS)

    Butson, Martin J; Cheung Tsang; Yu, Peter K N; Currie, Michael

    2004-01-01

    Assessment of surface dose delivered from radiotherapy x-ray beams for optimal results should be performed both inside and outside the prescribed treatment fields. An extrapolation technique can be used with radiographic film to perform surface dose assessment for open field high energy x-ray beams. This can produce an accurate two-dimensional map of surface dose if required. Results have shown that the surface percentage dose can be estimated within ±3% of parallel plate ionization chamber results with radiographic film using a series of film layers to produce an extrapolated result. Extrapolated percentage dose assessment for 10 cm, 20 cm and 30 cm square fields was estimated to be 15% ± 2%, 29% ± 3% and 38% ± 3% at the central axis and relatively uniform across the treatment field. The corresponding parallel plate ionization chamber measurements are 16%, 27% and 37%, respectively. Surface doses are also measured outside the treatment field which are mainly due to scattered electron contamination. To achieve this result, film calibration curves must be irradiated to similar x-ray field sizes as the experimental film to minimize quantitative variations in film optical density caused by varying x-ray spectrum with field size. (note)

  6. Green's functions potential fields on surfaces

    CERN Document Server

    Melnikov, Yuri A

    2017-01-01

    This book is comprehensive in its classical mathematical physics presentation, providing the reader with detailed instructions for obtaining Green's functions from scratch. Green's functions is an instrument easily accessible to practitioners who are engaged in design and exploitation of machines and structures in modern engineering practice. To date, there are no books available on the market that are devoted to the Green's function formalism for equations covered in this volume. The reader, with an undergraduate background in applied mathematics, can become an active user of the Green's function approach. For the first time, Green's functions are discussed for a specific class of problems dealing with potential fields induced in thin-wall structures and therefore, the reader will have first-hand access to a novel issue. This Work is accessible to researchers in applied mathematics, mechanics, and relevant disciplines such as engineering, as well as to upper level undergraduates and graduate students.

  7. Development of negative heavy ion sources for plasma potential measurement

    International Nuclear Information System (INIS)

    Sasao, M.; Okabe, Y.; Fujisawa, A.; Iguchi, H.; Fujita, J.; Yamaoka, H.; Wada, M.

    1991-10-01

    A plasma sputter negative ion source was studied for its applicability to the potential measurement of a fusion plasma. Both the beam current density and the beam energy spread are key issues. Energy spectra of a self extracted Au - beam from the source were measured under the condition of a constant work function of the production surface. The full width of half maximum (FWHM) increases from 3 eV to 9 eV monotonically as the target voltage increases from 50 V to 300 V, independently from the target surface work function of 2.2 - 3 eV. (author)

  8. Repulsive Casimir-Polder potential by a negative reflecting surface

    Science.gov (United States)

    Yuan, Qi-Zhang

    2015-07-01

    We present a scheme to generate an all-range long repulsive Casimir-Polder potential between a perfect negative reflecting surface and a ground-state atom. The repulsive potential is stable and does not decay with time. The Casimir-Polder potential is proportional to z-2 at short atom-surface distances and to z-4 at long atom-surface distances. Because of these advantages, this potential can help in building quantum reflectors, quantum levitating devices, and waveguides for matter waves.

  9. Summations over equilaterally triangulated surfaces and the critical string measure

    International Nuclear Information System (INIS)

    Smit, D.J.; Lawrence Berkeley Lab., CA

    1992-01-01

    We propose a new approach to the summation over dynamically triangulated Riemann surfaces which does not rely on properties of the potential in a matrix model. Instead, we formulate a purely algebraic discretization of critical string path integral. This is combined with a technique which assigns to each equilateral triangulation of a two-dimensional surface a Riemann surface defined over a certain finite extension of the field of rational numbers, i.e. an arithmetic surface. Thus we establish a new formulated in which the sum over randomly triangulated surfaces defines an invariant measure on the moduli space of arithmetic surfaces. It is shown that because of this it is far from obvious that this measure for large genera approximates the measure defined by the continuum theory, i.e. Liouville theory or critical string theory. In low genus this subtlety does not exist. In the case of critical string theory we explicitly compute the volume of the moduli space of arithmetic surfaces in terms of the modular height function and show that for low genus it approximates correctly the continuum measure. We also discuss a continuum limit which bears some resemblance with a double scaling limit in matrix models. (orig.)

  10. Surface aerosol measurements at Barrow during AGASP

    International Nuclear Information System (INIS)

    Bodhaine, B.A.; Dutton, E.G.; DeLuisi, J.J.

    1984-01-01

    Surface aerosol measurements were made at the Barrow GMCC Observatory during the AGASP flight series in March 1983. The condensation nucleus, scattering extinction coefficient, size distribution, and total aerosol optical depth measurements all clearly show conditions of background Arctic haze for March 9-11, a series of haze episodes during March 12-16, and a return to background haze for March 17-18. Angstrom exponents calculated from scattering coefficient data were low during March 9-11, relatively higher during March 12-14, and highest during March 15-18. Surface aerosol data and aerosol optical depth data are in good qualitative agreement for the 10-day period studied. Background haze was present when trajectories circled the Arctic basin, and haze episodes occurred when trajectories originated in western Asia and Europe

  11. Plasma measurements with surface barrier detectors

    International Nuclear Information System (INIS)

    Futch, A.H. Jr.; Bradley, A.E.

    1969-01-01

    A surface barrier detector system for measuring the loss rate of protons from a hydrogen plasma and their energy spectrum is described. A full width at half maximum (FWHM) resolution of 1.4 keV for 15-keV hydrogen atoms was obtained using a selected detector having a sensitive area of 3 mm 2 and a depletion depth of 700 microns

  12. Radioimmunoassay to quantitatively measure cell surface immunoglobulins

    International Nuclear Information System (INIS)

    Krishman, E.C.; Jewell, W.R.

    1975-01-01

    A radioimmunoassay techniques developed to quantitatively measure the presence of immunoglobulins on the surface of cells, is described. The amount of immunoglobulins found on different tumor cells varied from 200 to 1140 ng/10 6 cells. Determination of immunoglobulins on the peripheral lymphocytes obtained from different cancer patients varied between 340 to 1040 ng/10 6 cells. Cultured tumor cells, on the other hand, were found to contain negligible quantities of human IgG [pt

  13. Description of measurement techniques for surface contaminations

    International Nuclear Information System (INIS)

    Bourrez, E.

    2001-01-01

    The needs of evaluation of the surface contamination are numerous in the processes of production and management of radioactive waste. The market of radiation protection materials proposes a lot of devices answering to the almost all these needs. These device have however their conditions and particular limits for use. To realize correct measurements it is use the device, the technique and the methods adapted to the need, by taking into account the optimization of economical aspect. (N.C.)

  14. Doping profile measurement on textured silicon surface

    Science.gov (United States)

    Essa, Zahi; Taleb, Nadjib; Sermage, Bernard; Broussillou, Cédric; Bazer-Bachi, Barbara; Quillec, Maurice

    2018-04-01

    In crystalline silicon solar cells, the front surface is textured in order to lower the reflection of the incident light and increase the efficiency of the cell. This texturing whose dimensions are a few micrometers wide and high, often makes it difficult to determine the doping profile measurement. We have measured by secondary ion mass spectrometry (SIMS) and electrochemical capacitance voltage profiling the doping profile of implanted phosphorus in alkaline textured and in polished monocrystalline silicon wafers. The paper shows that SIMS gives accurate results provided the primary ion impact angle is small enough. Moreover, the comparison between these two techniques gives an estimation of the concentration of electrically inactive phosphorus atoms.

  15. Highly accurate surface maps from profilometer measurements

    Science.gov (United States)

    Medicus, Kate M.; Nelson, Jessica D.; Mandina, Mike P.

    2013-04-01

    Many aspheres and free-form optical surfaces are measured using a single line trace profilometer which is limiting because accurate 3D corrections are not possible with the single trace. We show a method to produce an accurate fully 2.5D surface height map when measuring a surface with a profilometer using only 6 traces and without expensive hardware. The 6 traces are taken at varying angular positions of the lens, rotating the part between each trace. The output height map contains low form error only, the first 36 Zernikes. The accuracy of the height map is ±10% of the actual Zernike values and within ±3% of the actual peak to valley number. The calculated Zernike values are affected by errors in the angular positioning, by the centering of the lens, and to a small effect, choices made in the processing algorithm. We have found that the angular positioning of the part should be better than 1?, which is achievable with typical hardware. The centering of the lens is essential to achieving accurate measurements. The part must be centered to within 0.5% of the diameter to achieve accurate results. This value is achievable with care, with an indicator, but the part must be edged to a clean diameter.

  16. Helicity and potential vorticity in the surface boundary layer turbulence

    Science.gov (United States)

    Chkhetiani, Otto; Kurgansky, Michael; Koprov, Boris; Koprov, Victor

    2016-04-01

    An experimental measurement of all three components of the velocity and vorticity vectors, as well as the temperature and its gradient, and potential vorticity, has been developed using four acoustic anemometers. Anemometers were placed at vertices of a tetrahedron, the horizontal base of which was a rectangular triangle with equal legs, and the upper point was exactly above the top of the right angle. The distance from the surface to the tetrahedron its base was 5.5 m, and the lengths of legs and a vertical edge were 5 m. The measurements were carried out of total duration near 100 hours both in stable and unstable stratification conditions (at the Tsimlyansk Scientific Station in a uniform area of virgin steppe 700 x 650 m, August 2012). A covariance-correlation matrix for turbulent variations in all measured values has been calculated. In the daytime horizontal and vertical components of the helicity are of the order of -0.03 and +0.01 m s-2, respectively. The nighttime signs remain unchanged, but the absolute values are several times smaller. It is confirmed also by statistics of a relative helicity. The cospectra and spectral correlation coefficients have been calculated for all helicity components. The time variations in the components of "instantaneous" relative helicity and potential vorticity are considered. Connections of helicity with Monin-Obukhov length and the wind vertical profile structure are discussed. This work was supported by the Russian Science Foundation (Project No 14-27-00134).

  17. Evaluation of Arctic broadband surface radiation measurements

    Science.gov (United States)

    Matsui, N.; Long, C. N.; Augustine, J.; Halliwell, D.; Uttal, T.; Longenecker, D.; Niebergall, O.; Wendell, J.; Albee, R.

    2012-02-01

    The Arctic is a challenging environment for making in-situ surface radiation measurements. A standard suite of radiation sensors is typically designed to measure incoming and outgoing shortwave (SW) and thermal infrared, or longwave (LW), radiation. Enhancements may include various sensors for measuring irradiance in narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are mounted on complex mechanical platforms (solar trackers) that keep sensors and shading devices trained on the sun along its diurnal path. High quality measurements require striking a balance between locating stations in a pristine undisturbed setting free of artificial blockage (such as from buildings and towers) and providing accessibility to allow operators to clean and maintain the instruments. Three significant sources of erroneous data in the Arctic include solar tracker malfunctions, rime/frost/snow deposition on the protective glass domes of the radiometers and operational problems due to limited operator access in extreme weather conditions. In this study, comparisons are made between the global and component sum (direct [vertical component] + diffuse) SW measurements. The difference between these two quantities (that theoretically should be zero) is used to illustrate the magnitude and seasonality of arctic radiation flux measurement problems. The problem of rime/frost/snow deposition is investigated in more detail for one case study utilizing both SW and LW measurements. Solutions to these operational problems that utilize measurement redundancy, more sophisticated heating and ventilation strategies and a more systematic program of operational support and subsequent data quality protocols are proposed.

  18. Frequency response in surface-potential driven electrohydrodynamics

    DEFF Research Database (Denmark)

    Ejsing, Louise Wellendorph; Smistrup, Kristian; Pedersen, Christian Møller

    2006-01-01

    Using a Fourier approach we offer a general solution to calculations of slip velocity within the circuit description of the electrohydrodynamics in a binary electrolyte confined by a plane surface with a modulated surface potential. We consider the case with a spatially constant intrinsic surface...... capacitance where the net flow rate is, in general, zero while harmonic rolls as well as time-averaged vortexlike components may exist depending on the spatial symmetry and extension of the surface potential. In general, the system displays a resonance behavior at a frequency corresponding to the inverse RC...

  19. Measurement of Redox Potential in Nanoecotoxicological Investigations

    Directory of Open Access Journals (Sweden)

    Ratna Tantra

    2012-01-01

    Full Text Available Redox potential has been identified by the Organisation for Economic Co-operation and Development (OECD as one of the parameters that should be investigated for the testing of manufactured nanomaterials. There is still some ambiguity concerning this parameter, i.e., as to what and how to measure, particularly when in a nanoecotoxicological context. In this study the redox potentials of six nanomaterials (either zinc oxide (ZnO or cerium oxide (CeO2 dispersions were measured using an oxidation-reduction potential (ORP electrode probe. The particles under testing differed in terms of their particle size and dispersion stability in deionised water and in various ecotox media. The ORP values of the various dispersions and how they fluctuate relative to each other are discussed. Results show that the ORP values are mainly governed by the type of liquid media employed, with little contributions from the nanoparticles. Seawater was shown to have reduced the ORP value, which was attributed to an increase in the concentration of reducing agents such as sulphites or the reduction of dissolved oxygen concentration. The lack of redox potential value contribution from the particles themselves is thought to be due to insufficient interaction of the particles at the Pt electrode of the ORP probe.

  20. Measurement of redox potential in nanoecotoxicological investigations.

    Science.gov (United States)

    Tantra, Ratna; Cackett, Alex; Peck, Roger; Gohil, Dipak; Snowden, Jacqueline

    2012-01-01

    Redox potential has been identified by the Organisation for Economic Co-operation and Development (OECD) as one of the parameters that should be investigated for the testing of manufactured nanomaterials. There is still some ambiguity concerning this parameter, i.e., as to what and how to measure, particularly when in a nanoecotoxicological context. In this study the redox potentials of six nanomaterials (either zinc oxide (ZnO) or cerium oxide (CeO(2))) dispersions were measured using an oxidation-reduction potential (ORP) electrode probe. The particles under testing differed in terms of their particle size and dispersion stability in deionised water and in various ecotox media. The ORP values of the various dispersions and how they fluctuate relative to each other are discussed. Results show that the ORP values are mainly governed by the type of liquid media employed, with little contributions from the nanoparticles. Seawater was shown to have reduced the ORP value, which was attributed to an increase in the concentration of reducing agents such as sulphites or the reduction of dissolved oxygen concentration. The lack of redox potential value contribution from the particles themselves is thought to be due to insufficient interaction of the particles at the Pt electrode of the ORP probe.

  1. Carbon potential measurement on some actinide carbides

    International Nuclear Information System (INIS)

    Anthonysamy, S.; Ananthasivan, K.; Kaliappan, I.; Chandramouli, V.; Vasudeva Rao, P.R.; Mathews, C.K.; Jacob, K.T.

    1994-01-01

    Uranium-Plutonium mixed carbides with a Pu/(U+Pu) ratio of 0.55 are to be used as the fuel in the Fast Breeder Test Reactor (FBTR) at Kalpakkam, India. Carburization of the stainless steel clad by this fuel is determined by its carbon potential. Because the carbon potential of this fuel composition is not available in the literature, it was measured by the methane-hydrogen gas equilibration technique. The sample was equilibrated with purified hydrogen and the equilibrium methane-to-hydrogen ratio in the gas phase was measured with a flame ionization detector. The carbon potential of the ThC-ThC 2 as well as Mo-Mo 2 C system, which is an important binary in the actinide-fission product-carbon systems, were also measured by this technique in the temperature range 973 to 1,173 K. The data for the Mo-Mo 2 C system are in agreement with values reported in the literature. The results for the ThC-ThC 2 system are different from estimated values with large uncertainty limits given in the literature. The data on (U, Pu) mixed carbides indicates the possibility of stainless steel clad attack under isothermal equilibrium conditions

  2. Influence of surface conductivity on the apparent zeta potential of calcite.

    Science.gov (United States)

    Li, Shuai; Leroy, Philippe; Heberling, Frank; Devau, Nicolas; Jougnot, Damien; Chiaberge, Christophe

    2016-04-15

    Zeta potential is a physicochemical parameter of particular importance in describing the surface electrical properties of charged porous media. However, the zeta potential of calcite is still poorly known because of the difficulty to interpret streaming potential experiments. The Helmholtz-Smoluchowski (HS) equation is widely used to estimate the apparent zeta potential from these experiments. However, this equation neglects the influence of surface conductivity on streaming potential. We present streaming potential and electrical conductivity measurements on a calcite powder in contact with an aqueous NaCl electrolyte. Our streaming potential model corrects the apparent zeta potential of calcite by accounting for the influence of surface conductivity and flow regime. We show that the HS equation seriously underestimates the zeta potential of calcite, particularly when the electrolyte is diluted (ionic strength ⩽ 0.01 M) because of calcite surface conductivity. The basic Stern model successfully predicted the corrected zeta potential by assuming that the zeta potential is located at the outer Helmholtz plane, i.e. without considering a stagnant diffuse layer at the calcite-water interface. The surface conductivity of calcite crystals was inferred from electrical conductivity measurements and computed using our basic Stern model. Surface conductivity was also successfully predicted by our surface complexation model. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Surface temperature measurement with radioactive kryptonates

    International Nuclear Information System (INIS)

    Pruzinec, J.; Piatrik, M.

    1976-01-01

    The preparation and use of radioactive kryptonates is described for measuring surface temperatures within the region of 45 to 70 degC. Two samples each were prepared of kryptonated beechwood and hydroquinone on a paper carrier. One sample served as the standard which during the experiment was placed in a thermostat at a constant temperature of 45 degC. The second sample was placed in another thermostat where the temperature changed from 45 to 70 degC. Both samples were in the thermostat for 30 mins. The temperature was raised in steps of 2.5 degC and the time of measurement was constant in both samples. The dependences are given of the drop in activity on temperature for both types of samples. The difference was determined of the drop in activity between the standard and the second sample and the relation for measuring the temperature of the sample was determined therefrom. (J.B.)

  4. Auditory evoked potential measurements in elasmobranchs

    Science.gov (United States)

    Casper, Brandon; Mann, David

    2005-04-01

    Auditory evoked potentials (AEP) were first used to examine hearing in elasmobranchs by Corwin and Bullock in the late 1970s and early 1980s, marking the first time AEPs had been measured in fishes. Results of these experiments identified the regions of the ear and brain in which sound is processed, though no actual hearing thresholds were measured. Those initial experiments provided the ground work for future AEP experiments to measure fish hearing abilities in a manner that is much faster and more convenient than classical conditioning. Data will be presented on recent experiments in which AEPs were used to measure the hearing thresholds of two species of elasmobranchs: the nurse shark, Ginglymostoma cirratum, and the yellow stingray, Urobatis jamaicencis. Audiograms were analyzed and compared to previously published audiograms obtained using classical conditioning with results indicating that hearing thresholds were similar for the two methods. These data suggest that AEP testing is a viable option when measuring hearing in elasmobranchs and can increase the speed in which future hearing measurements can be obtained.

  5. Experimental survey of the potential energy surfaces associated with fission

    International Nuclear Information System (INIS)

    Britt, H.C.

    1980-01-01

    Progress in the experimental determination of the properties of the potential energy surface associated with fission is reviewed. The importance of nuclear symmetry effects on the calculation of fission widths is demonstrated. Evidence is presented for the fragmentation of the mass-asymmetric second barrier in the thorium region and the axial asymmetric first barrier in the californium region. Detailed analyses of experimental data suggest the presence of two parallel second barriers; the normal mass-asymmetric, axial-symmetric barrier and a slightly higher mass-symmetric, axial-asymmetric barrier. Experimental barrier parameters are determined systematically and compared with calculations from various theoretical models. Techniques for expanding fission probability measurements to higher energies are discussed. (author)

  6. Measurement and removal of surface contamination

    International Nuclear Information System (INIS)

    Neider, M.; Tamberg, T.

    1990-01-01

    This is a critical reappraisal of the sampling factor which is important for indirect contamination measurement. The factor gives the radioactivity collected by means of a wipe sample as a fraction of the total loose radioactivity i.e. without firm adhesion. It is used in national and international standard specifications and stated, frequently with excessive conservatism, as 0.1. Secondly, the standard specifications for the testing and appraisal of surface materials in relation to their decontamination capacity and for testing the effect of decontamination agents hitherto bond and Co-60 and Cs-137 are to be expanded to include radioactive iodine, which is important in nuclear medicine. The selection of optimum surface materials will thus be put on an improved basis. (orig./DG) [de

  7. Measuring the Valence of Nanocrystal Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Owen, Jonathan Scharle [Columbia Univ., New York, NY (United States)

    2016-11-30

    The goal of this project is to understand and control the interplay between nanocrystal stoichiometry, surface ligand binding and exchange, and the optoelectronic properties of semiconductor nanocrystals in solution and in thin solid films. We pursued three research directions with this goal in mind: 1) We characterized nanocrystal stoichiometry and its influence on the binding of L-type and X-type ligands, including the thermodynamics of binding and the kinetics of ligand exchange. 2) We developed a quantitative understanding of the relationship between surface ligand passivation and photoluminescence quantum yield. 3) We developed methods to replace the organic ligands on the nanocrystal with halide ligands and controllably deposit these nanocrystals into thin films, where electrical measurements were used to investigate the electrical transport and internanocrystal electronic coupling.

  8. Surface motion and confinement potential for a microwave confined corona

    International Nuclear Information System (INIS)

    Ensley, D.L.

    1979-07-01

    Approximate time dependent solutions for surface velocities and potentials are given for a plane polarized microwave field confining a hot, over-dense plasma corona. Steady state solutions to Poissons' equation can be applied to the time dependent case, provided transit time effects are included. The product of ion pressure and potential wave (surface) velocity gives an average heating rate approx. 7/32 NKT 0 V/sub theta/ directly to the ions

  9. Characterization of electrical conductivity of carbon fiber reinforced plastic using surface potential distribution

    Science.gov (United States)

    Kikunaga, Kazuya; Terasaki, Nao

    2018-04-01

    A new method of evaluating electrical conductivity in a structural material such as carbon fiber reinforced plastic (CFRP) using surface potential is proposed. After the CFRP was charged by corona discharge, the surface potential distribution was measured by scanning a vibrating linear array sensor along the object surface with a high spatial resolution over a short duration. A correlation between the weave pattern of the CFRP and the surface potential distribution was observed. This result indicates that it is possible to evaluate the electrical conductivity of a material comprising conducting and insulating regions.

  10. Characterizing the surface charge of synthetic nanomembranes by the streaming potential method

    OpenAIRE

    Datta, Subhra; Conlisk, A. T.; Kanani, Dharmesh M.; Zydney, Andrew L.; Fissell, William H.; Roy, Shuvo

    2010-01-01

    The inference of the surface charge of polyethylene glycol (PEG)-coated and uncoated silicon membranes with nanoscale pore sizes from streaming potential measurements in the presence of finite electric double layer (EDL) effects is studied theoretically and experimentally. The developed theoretical model for inferring the pore wall surface charge density from streaming potential measurements is applicable to arbitrary pore cross-sectional shapes and accounts for the effect of finite salt conc...

  11. Evaluation of Arctic broadband surface radiation measurements

    Directory of Open Access Journals (Sweden)

    N. Matsui

    2012-02-01

    Full Text Available The Arctic is a challenging environment for making in-situ surface radiation measurements. A standard suite of radiation sensors is typically designed to measure incoming and outgoing shortwave (SW and thermal infrared, or longwave (LW, radiation. Enhancements may include various sensors for measuring irradiance in narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are mounted on complex mechanical platforms (solar trackers that keep sensors and shading devices trained on the sun along its diurnal path. High quality measurements require striking a balance between locating stations in a pristine undisturbed setting free of artificial blockage (such as from buildings and towers and providing accessibility to allow operators to clean and maintain the instruments. Three significant sources of erroneous data in the Arctic include solar tracker malfunctions, rime/frost/snow deposition on the protective glass domes of the radiometers and operational problems due to limited operator access in extreme weather conditions. In this study, comparisons are made between the global and component sum (direct [vertical component] + diffuse SW measurements. The difference between these two quantities (that theoretically should be zero is used to illustrate the magnitude and seasonality of arctic radiation flux measurement problems. The problem of rime/frost/snow deposition is investigated in more detail for one case study utilizing both SW and LW measurements. Solutions to these operational problems that utilize measurement redundancy, more sophisticated heating and ventilation strategies and a more systematic program of operational support and subsequent data quality protocols are proposed.

  12. SCANNING VOLTA POTENTIALS MEASUREMENTS OF METALS IN IRRADIATED AIR.

    Energy Technology Data Exchange (ETDEWEB)

    ISAACS, H.S.; ADZIC, G.; AND ENERGY SCIENCES AND TECHNOLOGY DEPARTMENT; JEFFCOATE, C.S.

    2000-10-22

    A method for direct dc measurement of the Volta potential is presented. High intensity synchrotron x-ray beams were used to locally irradiate the atmosphere adjacent to the metal surface and produce a conducting path between a sample and a reference probe. The direct measurements of potential in the ionized air could be made at probe heights of around 1 mm compared to less than 0.1 mm for the Kelvin probe. The measurements were similar to traditional Kelvin probe measurements, but had a poorer spatial resolution. In contrast to the Kelvin probe methods, the approach described allows observation of the current as a function of impressed voltage. Methods to improve the special resolution of the technique and applications to corrosion under coating will be presented.

  13. Calibration of areal surface topography measuring instruments

    Science.gov (United States)

    Seewig, J.; Eifler, M.

    2017-06-01

    The ISO standards which are related to the calibration of areal surface topography measuring instruments are the ISO 25178-6xx series which defines the relevant metrological characteristics for the calibration of different measuring principles and the ISO 25178-7xx series which defines the actual calibration procedures. As the field of areal measurement is however not yet fully standardized, there are still open questions to be addressed which are subject to current research. Based on this, selected research results of the authors in this area are presented. This includes the design and fabrication of areal material measures. For this topic, two examples are presented with the direct laser writing of a stepless material measure for the calibration of the height axis which is based on the Abbott- Curve and the manufacturing of a Siemens star for the determination of the lateral resolution limit. Based on these results, as well a new definition for the resolution criterion, the small scale fidelity, which is still under discussion, is presented. Additionally, a software solution for automated calibration procedures is outlined.

  14. LOFT fuel rod surface temperature measurement testing

    International Nuclear Information System (INIS)

    Eaton, A.M.; Tolman, E.L.; Solbrig, C.W.

    1978-01-01

    Testing of the LOFT fuel rod cladding surface thermocouples has been performed to evaluate how accurately the LOFT thermocouples measure the cladding surface temperature during a loss-of-coolant accident (LOCA) sequence and what effect, if any, the thermocouple would have on core performance. Extensive testing has been done to characterize the thermocouple design. Thermal cycling and corrosion testing of the thermocouple weld design have provided an expected lifetime of 6000 hours when exposed to reactor coolant conditions of 620 K and 15.9 MPa and to sixteen thermal cycles with an initial temperature of 480 K and peak temperatures ranging from 870 to 1200K. Departure from nucleate boiling (DNB) tests have indicated a DNB penalty (5 to 28% lower) during steady state operation and negligible effects during LOCA blowdown caused by the LOFT fuel rod surface thermocouple arrangement. Experience with the thermocouple design in Power Burst Facility (PBF) and LOFT nonnuclear blowdown testing has been quite satisfactory. Tests discussed here were conducted using both stainless steel and zircaloy-clad electrically heated rod in the LOFT Test Support Facility (LTSF) blowdown simulation loop

  15. Intelligent sampling for the measurement of structured surfaces

    International Nuclear Information System (INIS)

    Wang, J; Jiang, X; Blunt, L A; Scott, P J; Leach, R K

    2012-01-01

    Uniform sampling in metrology has known drawbacks such as coherent spectral aliasing and a lack of efficiency in terms of measuring time and data storage. The requirement for intelligent sampling strategies has been outlined over recent years, particularly where the measurement of structured surfaces is concerned. Most of the present research on intelligent sampling has focused on dimensional metrology using coordinate-measuring machines with little reported on the area of surface metrology. In the research reported here, potential intelligent sampling strategies for surface topography measurement of structured surfaces are investigated by using numerical simulation and experimental verification. The methods include the jittered uniform method, low-discrepancy pattern sampling and several adaptive methods which originate from computer graphics, coordinate metrology and previous research by the authors. By combining the use of advanced reconstruction methods and feature-based characterization techniques, the measurement performance of the sampling methods is studied using case studies. The advantages, stability and feasibility of these techniques for practical measurements are discussed. (paper)

  16. Potential utility of the thematic mapper for surface mine monitoring

    International Nuclear Information System (INIS)

    Irons, J.R.; Lachowski, H.M.

    1981-01-01

    One of many potential applications of the thematic mapper (TM) is surface mine monitoring. To assess this potential, data acquired by an aircraft multispectral scanner over Pennsylvania surface mines were preprocessed to simulate the anticipated spectral, spatial, and radiometric characteristics of TM data. False color imagery and thematic maps were derived from the simulated data and compared to imagery and maps derived from LANDSAT multispectral scanner subsystems data. On the basis of this comparison, TM data should definitely increase the detail and accuracy of remotely acquired surface mine information and may enable the remote determination of compliance with reclamation regulations

  17. Osteogenic potential of laser modified and conditioned titanium zirconium surfaces

    Directory of Open Access Journals (Sweden)

    P David Charles

    2016-01-01

    Full Text Available Statement of Problem: The osseointegration of dental implant is related to their composition and surface treatment. Titanium zirconium (TiZr has been introduced as an alternative to the commercially pure titanium and its alloys as dental implant material, which is attributed to its superior mechanical and biological properties. Surface treatments of TiZr have been introduced to enhance their osseointegration ability; however, reliable, easy to use surface modification technique has not been established. Purpose: The purpose of this study was to evaluate and compare the effect of neodymium-doped yttrium aluminum garnet (Nd-YAG laser surface treatment of TiZr implant alloy on their osteogenic potential. Materials and Methods: Twenty disc-shaped samples of 5 mm diameter and 2 mm height were milled from the TiZr alloy ingot. The polished discs were ultrasonically cleaned in distilled water. Ten samples each were randomly selected as Group A control samples and Group B consisted of Nd-YAG laser surface etched and conditioned test samples. These were evaluated for cellular response. Cellular adhesion and proliferation were quantified, and the results were statistically analyzed using nonparametric analysis. Cellular morphology was observed using electron and epiflurosence microscopy. Results: Nd-YAG laser surface modified and conditioned TiZr samples increased the osteogenic potential. Conclusion: Nd-YAG laser surface modification of TiZr, improves the cellular activity, surface roughness, and wettability, thereby increasing the osteogenic potential.

  18. Surface effects on mean inner potentials studied using density functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Pennington, Robert S., E-mail: robert.pennington@uni-ulm.de [Institute for Experimental Physics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm (Germany); Boothroyd, Chris B.; Dunin-Borkowski, Rafal E. [Ernst Ruska-Centre and Peter Grüneberg Institute, Forschungzentrum Jülich, 52425 Jülich (Germany)

    2015-12-15

    Quantitative materials characterization using electron holography frequently requires knowledge of the mean inner potential, but reported experimental mean inner potential measurements can vary widely. Using density functional theory, we have simulated the mean inner potential for materials with a range of different surface conditions and geometries. We use both “thin-film” and “nanowire” specimen geometries. We consider clean bulk-terminated surfaces with different facets and surface reconstructions using atom positions from both structural optimization and experimental data and we also consider surfaces both with and without adsorbates. We find that the mean inner potential is surface-dependent, with the strongest dependency on surface adsorbates. We discuss the outlook and perspective for future mean inner potential measurements. - Highlights: • Density functional theory (DFT) is used to simulate mean inner potentials (MIP). • Applications for MIP electron holography measurements are considered. • MIPs are found to be surface-dependent, for thin-film and nanowire geometries. • The DFT simulation precision is extensively tested for multiple materials. • Surface adsorbates can create a strong positive or negative effect.

  19. Biaxial potential of surface-stabilized ferroelectric liquid crystals

    Science.gov (United States)

    Kaznacheev, Anatoly; Pozhidaev, Evgeny; Rudyak, Vladimir; Emelyanenko, Alexander V.; Khokhlov, Alexei

    2018-04-01

    A biaxial surface potential Φs of smectic-C* surface-stabilized ferroelectric liquid crystals (SSFLCs) is introduced in this paper to explain the experimentally observed electric-field dependence of polarization P˜cell(E ) , in particular the shape of the static hysteresis loops. Our potential consists of three independent parts. The first nonpolar part Φn describes the deviation of the prime director n (which is the most probable orientation of the long molecular axes) from the easy alignment axis R , which is located in the boundary surface plane. It is introduced in the same manner as the uniaxial Rapini potential. The second part Φp of the potential is a polar term associated with the presence of the polar axis in a FLC. The third part Φm relates to the inherent FLC biaxiality, which has not been taken into consideration previously. The Φm part takes into account the deviations of the secondary director m (which is the most probable orientation of the short molecular axes) from the normal to the boundary surface. The overall surface potential Φs, which is a sum of Φn,Φp , and Φm, allows one to model the conditions when either one, two, or three minima of the SSFLC cell free energy are realized depending on the biaxiality extent. A monodomain or polydomain structure, as well as the bistability or monostability of SSFLC cells, depends on the number of free-energy minima, as confirmed experimentally. In this paper, we analyze the biaxiality impact on the FLC alignment. We also answer the question of whether the bistable or monostable structure can be formed in an SSFLC cell. Our approach is essentially based on a consideration of the biaxial surface potential, while the uniaxial surface potential cannot adequately describe the experimental observations in the FLC.

  20. Effects of water chemistry and potential distribution on electrochemical corrosion potential measurements in 553 K pure water

    International Nuclear Information System (INIS)

    Ishida, Kazushige; Wada, Yoichi; Tachibana, Masahiko; Ota, Nobuyuki; Aizawa, Motohiro

    2013-01-01

    The effects of water chemistry distribution on the potential of a reference electrode and of the potential distribution on the measured potential should be known qualitatively to obtain accurate electrochemical corrosion potential (ECP) data in BWRs. First, the effects of oxygen on a platinum reference electrode were studied in 553 K pure water containing dissolved hydrogen (DH) concentration of 26 - 10 5 μg kg -1 (ppb). The platinum electrode worked in the same way as the theoretical hydrogen electrode under the condition that the molar ratio of DH to dissolved oxygen (DO) was more than 10 and that DO was less than 100 ppb. Second, the effects of potential distribution on the measured potential were studied by using the ECP measurement part without platinum deposition on the surfaces connected to another ECP measurement part with platinum deposition on the surfaces in 553 K pure water containing 100 - 130 ppb of DH or 100 - 130 ppb of DH plus 400 ppb of hydrogen peroxide. Measured potentials for each ECP measurement part were in good agreement with literature data for each surface condition. The lead wire connecting point did not affect the measured potential. Potential should be measured at the nearest point from the reference electrode in which case it will be not affected by either the potential distribution or the connection point of the lead wire in pure water. (author)

  1. Quadrotor helicopter for surface hydrological measurements

    Science.gov (United States)

    Pagano, C.; Tauro, F.; Porfiri, M.; Grimaldi, S.

    2013-12-01

    Surface hydrological measurements are typically performed through user-assisted and intrusive field methodologies which can be inadequate to monitor remote and extended areas. In this poster, we present the design and development of a quadrotor helicopter equipped with digital acquisition system and image calibration units for surface flow measurements. This custom-built aerial vehicle is engineered to be lightweight, low-cost, highly customizable, and stable to guarantee optimal image quality. Quadricopter stability guarantees minimal vibrations during image acquisition and, therefore, improved accuracy in flow velocity estimation through large scale particle image velocimetry algorithms or particle tracking procedures. Stability during the vehicle pitching and rolling is achieved by adopting large arm span and high-wing configurations. Further, the vehicle framework is composed of lightweight aluminum and durable carbon fiber for optimal resilience. The open source Ardupilot microcontroller is used for remote control of the quadricopter. The microcontroller includes an inertial measurement unit (IMU) equipped with accelerometers and gyroscopes for stable flight through feedback control. The vehicle is powered by a 3 cell (11.1V) 3000 mAh Lithium-polymer battery. Electronic equipment and wiring are hosted into the hollow arms and on several carbon fiber platforms in the waterproof fuselage. Four 35A high-torque motors are supported at the far end of each arm with 10 × 4.7 inch propellers. Energy dissipation during landing is accomplished by four pivoting legs that, through the use of shock absorbers, prevent the impact energy from affecting the frame thus causing significant damage. The data capturing system consists of a GoPro Hero3 camera and in-house built camera gimbal and shock absorber damping device. The camera gimbal, hosted below the vehicle fuselage, is engineered to maintain the orthogonality of the camera axis with respect to the water surface by

  2. The Contribution of Surface Potential to Diverse Problems in Electrostatics

    International Nuclear Information System (INIS)

    Horenstein, M

    2015-01-01

    Electrostatics spans many different subject areas. Some comprise “good electrostatics,” where charge is used for desirable purposes. Such areas include industrial manufacturing, electrophotography, surface modification, precipitators, aerosol control, and MEMS. Other areas comprise “bad electrostatics,” where charge is undesirable. Such areas include hazardous discharges, ESD, health effects, nuisance triboelectrification, particle contamination, and lightning. Conference proceedings such as this one inevitably include papers grouped around these topics. One common thread throughout is the surface potential developed when charge resides on an insulator surface. Often, the charged insulator will be in intimate contact with a ground plane. At other times, the charged insulator will be isolated. In either case, the resulting surface potential is important to such processes as propagating brush discharges, charge along a moving web, electrostatic biasing effects in MEMS, non-contacting voltmeters, field-effect transistor sensors, and the maximum possible charge on a woven fabric. (paper)

  3. Sliding surface searching method for slopes containing a potential weak structural surface

    Directory of Open Access Journals (Sweden)

    Aijun Yao

    2014-06-01

    Full Text Available Weak structural surface is one of the key factors controlling the stability of slopes. The stability of rock slopes is in general concerned with set of discontinuities. However, in soft rocks, failure can occur along surfaces approaching to a circular failure surface. To better understand the position of potential sliding surface, a new method called simplex-finite stochastic tracking method is proposed. This method basically divides sliding surface into two parts: one is described by smooth curve obtained by random searching, the other one is polyline formed by the weak structural surface. Single or multiple sliding surfaces can be considered, and consequently several types of combined sliding surfaces can be simulated. The paper will adopt the arc-polyline to simulate potential sliding surface and analyze the searching process of sliding surface. Accordingly, software for slope stability analysis using this method was developed and applied in real cases. The results show that, using simplex-finite stochastic tracking method, it is possible to locate the position of a potential sliding surface in the slope.

  4. Time-dependent image potential at a metal surface

    International Nuclear Information System (INIS)

    Alducin, M.; Diez Muino, R.; Juaristi, J.I.

    2003-01-01

    Transient effects in the image potential induced by a point charge suddenly created in front of a metal surface are studied. The time evolution of the image potential is calculated using linear response theory. Two different time scales are defined: (i) the time required for the creation of the image potential and (ii) the time it takes to converge to its stationary value. Their dependence on the distance of the charge to the surface is discussed. The effect of the electron gas damping is also analyzed. For a typical metallic density, the order of magnitude of the creation time is 0.1 fs, whereas for a charge created close to the surface the convergence time is around 1-2 fs

  5. An adaptive interpolation scheme for molecular potential energy surfaces

    Science.gov (United States)

    Kowalewski, Markus; Larsson, Elisabeth; Heryudono, Alfa

    2016-08-01

    The calculation of potential energy surfaces for quantum dynamics can be a time consuming task—especially when a high level of theory for the electronic structure calculation is required. We propose an adaptive interpolation algorithm based on polyharmonic splines combined with a partition of unity approach. The adaptive node refinement allows to greatly reduce the number of sample points by employing a local error estimate. The algorithm and its scaling behavior are evaluated for a model function in 2, 3, and 4 dimensions. The developed algorithm allows for a more rapid and reliable interpolation of a potential energy surface within a given accuracy compared to the non-adaptive version.

  6. Reversible Compositional Control of Oxide Surfaces by Electrochemical Potentials

    KAUST Repository

    Mutoro, Eva

    2012-01-05

    Perovskite oxides can exhibit a wide range of interesting characteristics such as being catalytically active and electronically/ionically conducting, and thus, they have been used in a number of solid-state devices such as solid oxide fuel cells (SOFCs) and sensors. As the surface compositions of perovskites can greatly influence the catalytic properties, knowing and controlling their surface compositions is crucial to enhance device performance. In this study, we demonstrate that the surface strontium (Sr) and cobalt (Co) concentrations of perovskite-based thin films can be controlled reversibly at elevated temperatures by applying small electrical potential biases. The surface compositional changes of La 0.8Sr 0.2CoO 3-δ (LSC 113), (La 0.5Sr 0.5) 2CoO 4±δ (LSC 214), and LSC 214-decorated LSC 113 films (LSC 113/214) were investigated in situ by utilizing synchrotron-based X-ray photoelectron spectroscopy (XPS), where the largest changes of surface Sr were found for the LSC 113/214 surface. These findings offer the potential of reversibly controlling the surface functionality of perovskites. © 2011 American Chemical Society.

  7. Lunar Surface Potential Increases during Terrestrial Bow Shock Traversals

    Science.gov (United States)

    Collier, Michael R.; Stubbs, Timothy J.; Hills, H. Kent; Halekas, Jasper; Farrell, William M.; Delory, Greg T.; Espley, Jared; Freeman, John W.; Vondrak, Richard R.; Kasper, Justin

    2009-01-01

    Since the Apollo era the electric potential of the Moon has been a subject of interest and debate. Deployed by three Apollo missions, Apollo 12, Apollo 14 and Apollo 15, the Suprathermal Ion Detector Experiment (SIDE) determined the sunlit lunar surface potential to be about +10 Volts using the energy spectra of lunar ionospheric thermal ions accelerated toward the Moon. We present an analysis of Apollo 14 SIDE "resonance" events that indicate the lunar surface potential increases when the Moon traverses the dawn bow shock. By analyzing Wind spacecraft crossings of the terrestrial bow shock at approximately this location and employing current balancing models of the lunar surface, we suggest causes for the increasing potential. Determining the origin of this phenomenon will improve our ability to predict the lunar surface potential in support of human exploration as well as provide models for the behavior of other airless bodies when they traverse similar features such as interplanetary shocks, both of which are goals of the NASA Lunar Science Institute's Dynamic Response of the Environment At the Moon (DREAM) team.

  8. The potentially neglected culprit of DC surface flashover: electron migration under temperature gradients.

    Science.gov (United States)

    Li, Chuanyang; Hu, Jun; Lin, Chuanjie; He, Jinliang

    2017-06-12

    This report intends to reveal the role of electron migration and its effects in triggering direct current (DC) surface flashover under temperature gradient conditions when using epoxy-based insulating composites. The surface potential and the surface flashover voltage are both measured using insulators that are bridged between two thermo-regulated electrodes. The space charge injection and migration properties under different temperature are detected. The results show that the surface potential rises significantly because of electron migration near the high voltage (HV) electrode under high temperature conditions, thus creating an "analogous ineffective region". The expansion of this "analogous ineffective region" results in most of the voltage drop occurring near the ground electrode, which serves as an important factor triggering positive streamers across the insulation surface. This work is helpful in understanding of DC surface flashover mechanism from a new perspective and also has important significance in design of a suitable DC insulator to avoid surface flashover problem.

  9. Optimized surface-slab excited-state muffin-tin potential and surface core level shifts

    International Nuclear Information System (INIS)

    Rundgren, J.

    2003-01-01

    An optimized muffin-tin (MT) potential for surface slabs with preassigned surface core-level shifts (SCLS's) is presented. By using the MT radii as adjustable parameters the model is able to conserve the definition of the SCLS with respect to the bulk and concurrently to generate a potential that is continuous at the MT radii. The model is conceived for elastic electron scattering in a surface slab with exchange-correlation interaction described by the local density approximation. The model employs two data bases for the self-energy of the signal electron (after Hedin and Lundqvist or Sernelius). The potential model is discussed in detail with two surface structures Be(101-bar0), for which SCLS's are available, and Cu(111)p(2x2)Cs, in which the close-packed radii of the atoms are extremely different. It is considered plausible that tensor LEED based on an optimized MT potential can be used for determining SCLS's

  10. Streaming potential revisited: the influence of convection on the surface conductivity.

    Science.gov (United States)

    Saini, Rakesh; Garg, Abhinandan; Barz, Dominik P J

    2014-09-16

    Electrokinetic phenomena play an important role in the electrical characterization of surfaces. In terms of planar or porous substrates, streaming potential and/or streaming current measurements can be used to determine the zeta potential of the substrates in contact with aqueous electrolytes. In this work, we perform electrical impedance spectroscopy measurements to infer the electrical resistance in a microchannel with the same conditions as for a streaming potential experiment. Novel correlations are derived to relate the streaming current and streaming potential to the Reynolds number of the channel flow. Our results not only quantify the influence of surface conductivity, and here especially the contribution of the stagnant layer, but also reveal that channel resistance and therefore zeta potential are influenced by the flow in the case of low ionic strengths. We conclude that convection can have a significant impact on the electrical double layer configuration which is reflected by changes in the surfaces conductivity.

  11. Experimental measurements of negative hydrogen ion production from surfaces

    International Nuclear Information System (INIS)

    Graham, W.G.

    1977-09-01

    Experimental measurements of the production of H - from surfaces bombarded with hydrogen are reviewed. Some measurements of H + and H 0 production from surfaces are also discussed with particular emphasis on work which might be relevant to ion source applications

  12. Tuning the surface potential of Ag surfaces by chemisorption of oppositely-oriented thiolated carborane dipoles

    Czech Academy of Sciences Publication Activity Database

    Lübben, J.F.; Baše, Tomáš; Rupper, P.; Künniger, T.; Macháček, Jan; Guimond, S.

    2011-01-01

    Roč. 354, č. 1 (2011), s. 168-174 ISSN 0021-9797 R&D Projects: GA AV ČR(CZ) IAA400320901 Keywords : Adsorption * Thiolated carboranes * Silver surface * Surface potential * X-ray photoelectron spectroscopy Subject RIV: CA - Inorganic Chemistry Impact factor: 3.070, year: 2011

  13. A statistical nanomechanism of biomolecular patterning actuated by surface potential

    Science.gov (United States)

    Lin, Chih-Ting; Lin, Chih-Hao

    2011-02-01

    Biomolecular patterning on a nanoscale/microscale on chip surfaces is one of the most important techniques used in vitro biochip technologies. Here, we report upon a stochastic mechanics model we have developed for biomolecular patterning controlled by surface potential. The probabilistic biomolecular surface adsorption behavior can be modeled by considering the potential difference between the binding and nonbinding states. To verify our model, we experimentally implemented a method of electroactivated biomolecular patterning technology and the resulting fluorescence intensity matched the prediction of the developed model quite well. Based on this result, we also experimentally demonstrated the creation of a bovine serum albumin pattern with a width of 200 nm in 5 min operations. This submicron noncovalent-binding biomolecular pattern can be maintained for hours after removing the applied electrical voltage. These stochastic understandings and experimental results not only prove the feasibility of submicron biomolecular patterns on chips but also pave the way for nanoscale interfacial-bioelectrical engineering.

  14. Application of Volta potential mapping to determine metal surface defects

    International Nuclear Information System (INIS)

    Nazarov, A.; Thierry, D.

    2007-01-01

    As a rule, stress or fatigue cracks originate from various surface imperfections, such as pits, inclusions or locations showing a residual stress. It would be very helpful for material selection to be able to predict the likelihood of environment-assisted cracking or pitting corrosion. By using Scanning Kelvin Probe (the vibrating capacitor with a spatial resolution of 80 μm) the profiling of metal electron work function (Volta potential) in air is applied to the metal surfaces showing residual stress, MnS inclusions and wearing. The Volta potential is influenced by the energy of electrons at the Fermi level and drops generally across the metal/oxide/air interfaces. Inclusions (e.g. MnS) impair continuity of the passive film that locally decreases Volta potential. The stress applied gives rise to dislocations, microcracks and vacancies in the metal and the surface oxide. The defects decrease Volta and corrosion potentials; reduce the overvoltage for processes of passivity breakdown and anodic metal dissolution. These 'anodic' defects can be visualized in potential mapping that can help us to predict locations with higher risk of pitting corrosion or cracking

  15. Communication: Fitting potential energy surfaces with fundamental invariant neural network

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Kejie; Chen, Jun; Zhao, Zhiqiang; Zhang, Dong H., E-mail: zhangdh@dicp.ac.cn [State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People’s Republic of China and University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China. (China)

    2016-08-21

    A more flexible neural network (NN) method using the fundamental invariants (FIs) as the input vector is proposed in the construction of potential energy surfaces for molecular systems involving identical atoms. Mathematically, FIs finitely generate the permutation invariant polynomial (PIP) ring. In combination with NN, fundamental invariant neural network (FI-NN) can approximate any function to arbitrary accuracy. Because FI-NN minimizes the size of input permutation invariant polynomials, it can efficiently reduce the evaluation time of potential energy, in particular for polyatomic systems. In this work, we provide the FIs for all possible molecular systems up to five atoms. Potential energy surfaces for OH{sub 3} and CH{sub 4} were constructed with FI-NN, with the accuracy confirmed by full-dimensional quantum dynamic scattering and bound state calculations.

  16. Valence bond model potential energy surface for H4

    International Nuclear Information System (INIS)

    Silver, D.M.; Brown, N.J.

    1980-01-01

    Potential energy surfaces for the H 4 system are derived using the valence bond procedure. An ab initio evaluation of the valence bond energy expression is described and some of its numerical properties are given. Next, four semiempirical evaluations of the valence bond energy are defined and parametrized to yield reasonable agreement with various ab initio calculations of H 4 energies. Characteristics of these four H 4 surfaces are described by means of tabulated energy minima and equipotential contour maps for selected geometrical arrangements of the four nuclei

  17. Hydrologic Science and Satellite Measurements of Surface Water (Invited)

    Science.gov (United States)

    Alsdorf, D. E.; Mognard, N. M.; Lettenmaier, D. P.

    2010-12-01

    While significant advances continue to be made for satellite measurements of surface waters, important science and application opportunities remain. Examples include the following: (1) Our current methods of measuring floodwater dynamics are either sparsely distributed or temporally inadequate. As an example, flood depths are measured by using high water marks, which capture only the peak of the flood wave, not its temporal variability. (2) Discharge is well measured at individual points along stream networks using in-situ gauges, but these do not capture within-reach hydraulic variability such as the water surface slope changes on the rising and falling limbs of flood waves. (3) Just a 1.0 mm/day error in ET over the Congo Basin translates to a 35,000 m3/s discharge error. Knowing the discharge of the Congo River and its many tributaries should significantly improve our understanding of the water balance throughout the basin. The Congo is exemplary of many other basins around the globe. (4) Arctic hydrology is punctuated by millions of unmeasured lakes. Globally, there might be as many as 30 million lakes larger than a hectare. Storage changes in these lakes are nearly unknown, but in the Arctic such changes are likely an indication of global warming. (5) Well over 100 rivers cross international boundaries, yet the sharing of water data is poor. Overcoming this helps to better manage the entire river basin while also providing a better assessment of potential water related disasters. The Surface Water and Ocean Topography (SWOT, http://swot.jpl.nasa.gov/) mission is designed to meet these needs by providing global measurements of surface water hydrodynamics. SWOT will allow estimates of discharge in rivers wider than 100m (50m goal) and storage changes in water bodies larger than 250m by 250m (and likely as small as one hectare).

  18. Detecting rapid mass movements using electrical self-potential measurements

    Science.gov (United States)

    Heinze, Thomas; Limbrock, Jonas; Pudasaini, Shiva P.; Kemna, Andreas

    2017-04-01

    Rapid mass movements are a latent danger for lives and infrastructure in almost any part of the world. Often such mass movements are caused by increasing pore pressure, for example, landslides after heavy rainfall or dam breaking after intrusion of water in the dam. Among several other geophysical methods used to observe water movement, the electrical self-potential method has been applied to a broad range of monitoring studies, especially focusing on volcanism and dam leakage but also during hydraulic fracturing and for earthquake prediction. Electrical self-potential signals may be caused by various mechanisms. Though, the most relevant source of the self-potential field in the given context is the streaming potential, caused by a flowing electrolyte through porous media with electrically charged internal surfaces. So far, existing models focus on monitoring water flow in non-deformable porous media. However, as the self-potential is sensitive to hydraulic parameters of the soil, any change in these parameters will cause an alteration of the electric signal. Mass movement will significantly influence the hydraulic parameters of the solid as well as the pressure field, assuming that fluid movement is faster than the pressure diffusion. We will present results of laboratory experiments under drained and undrained conditions with fluid triggered as well as manually triggered mass movements, monitored with self-potential measurements. For the undrained scenarios, we observe a clear correlation between the mass movements and signals in the electric potential, which clearly differ from the underlying potential variations due to increased saturation and fluid flow. In the drained experiments, we do not observe any measurable change in the electric potential. We therefore assume that change in fluid properties and release of the load causes disturbances in flow and streaming potential. We will discuss results of numerical simulations reproducing the observed effect. Our

  19. Measurement of electric potential distribution in dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Veretel' nik, V I; Dergozubov, K A; Evdokimov, O B; Shevelev, G E [Tomskij Politekhnicheskij Inst. (USSR). Nauchno-Issledovatel' skij Inst. Ehlektronnoj Introskopii

    1976-05-01

    A radiation method of potential probing in a substance is described. The method is based upon the influence of the electric field upon the emission of secondary electrons expelled by ..gamma..-irradiation from the studied sample.

  20. Emotioncy: A Potential Measure of Readability

    Science.gov (United States)

    Pishghadamn, Reza; Abbasnejad, Hannaheh

    2016-01-01

    Given the deficiencies of readability formulae as reliable tools for measuring text readability in educational settings, this study aims to offer a new measure to improve the current methods of testing the readability levels of texts through the incorporation of the newly-developed concept of emotioncy. To this end, a group of 221 students were…

  1. He-, Ne-, and Ar-phosgene intermolecular potential energy surfaces

    DEFF Research Database (Denmark)

    Munteanu, Cristian R.; Henriksen, Christian; Felker, Peter M.

    2013-01-01

    Using the CCSD(T) model, we evaluated the intermolecular potential energy surfaces of the He-, Ne-, and Ar-phosgene complexes. We considered a representative number of intermolecular geometries for which we calculated the corresponding interaction energies with the augmented (He complex) and doub...... of the complexes, providing valuable results for future experimental investigations. Comparing our results to those previously available for other phosgene complexes, we suggest that the results for Cl2-phosgene should be revised....

  2. Electronic structure, molecular bonding and potential energy surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ruedenberg, K. [Ames Laboratory, IA (United States)

    1993-12-01

    By virtue of the universal validity of the generalized Born-Oppenheimer separation, potential energy surfaces (PES`) represent the central conceptual as well as quantitative entities of chemical physics and provide the basis for the understanding of most physicochemical phenomena in many diverse fields. The research in this group deals with the elucidation of general properties of PES` as well as with the quantitative determination of PES` for concrete systems, in particular pertaining to reactions involving carbon, oxygen, nitrogen and hydrogen molecules.

  3. Surface deformation during an action potential in pearled cells

    Science.gov (United States)

    Mussel, Matan; Fillafer, Christian; Ben-Porath, Gal; Schneider, Matthias F.

    2017-11-01

    Electric pulses in biological cells (action potentials) have been reported to be accompanied by a propagating cell-surface deformation with a nanoscale amplitude. Typically, this cell surface is covered by external layers of polymer material (extracellular matrix, cell wall material, etc.). It was recently demonstrated in excitable plant cells (Chara braunii) that the rigid external layer (cell wall) hinders the underlying deformation. When the cell membrane was separated from the cell wall by osmosis, a mechanical deformation, in the micrometer range, was observed upon excitation of the cell. The underlying mechanism of this mechanical pulse has, to date, remained elusive. Herein we report that Chara cells can undergo a pearling instability, and when the pearled fragments were excited even larger and more regular cell shape changes were observed (˜10 -100 μ m in amplitude). These transient cellular deformations were captured by a curvature model that is based on three parameters: surface tension, bending rigidity, and pressure difference across the surface. In this paper these parameters are extracted by curve-fitting to the experimental cellular shapes at rest and during excitation. This is a necessary step to identify the mechanical parameters that change during an action potential.

  4. Theoretical studies of potential energy surfaces and computational methods

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, R. [Argonne National Laboratory, IL (United States)

    1993-12-01

    This project involves the development, implementation, and application of theoretical methods for the calculation and characterization of potential energy surfaces involving molecular species that occur in hydrocarbon combustion. These potential energy surfaces require an accurate and balanced treatment of reactants, intermediates, and products. This difficult challenge is met with general multiconfiguration self-consistent-field (MCSCF) and multireference single- and double-excitation configuration interaction (MRSDCI) methods. In contrast to the more common single-reference electronic structure methods, this approach is capable of describing accurately molecular systems that are highly distorted away from their equilibrium geometries, including reactant, fragment, and transition-state geometries, and of describing regions of the potential surface that are associated with electronic wave functions of widely varying nature. The MCSCF reference wave functions are designed to be sufficiently flexible to describe qualitatively the changes in the electronic structure over the broad range of geometries of interest. The necessary mixing of ionic, covalent, and Rydberg contributions, along with the appropriate treatment of the different electron-spin components (e.g. closed shell, high-spin open-shell, low-spin open shell, radical, diradical, etc.) of the wave functions, are treated correctly at this level. Further treatment of electron correlation effects is included using large scale multireference CI wave functions, particularly including the single and double excitations relative to the MCSCF reference space. This leads to the most flexible and accurate large-scale MRSDCI wave functions that have been used to date in global PES studies.

  5. Etalon (standard) for surface potential distribution produced by electric activity of the heart.

    Science.gov (United States)

    Szathmáry, V; Ruttkay-Nedecký, I

    1981-01-01

    The authors submit etalon (standard) equipotential maps as an aid in the evaluation of maps of surface potential distributions in living subjects. They were obtained by measuring potentials on the surface of an electrolytic tank shaped like the thorax. The individual etalon maps were determined in such a way that the parameters of the physical dipole forming the source of the electric field in the tank corresponded to the mean vectorcardiographic parameters measured in a healthy population sample. The technique also allows a quantitative estimate of the degree of non-dipolarity of the heart as the source of the electric field.

  6. Yukawa Potential, Panharmonic Measure and Brownian Motion

    Directory of Open Access Journals (Sweden)

    Antti Rasila

    2018-05-01

    Full Text Available This paper continues our earlier investigation, where a walk-on-spheres (WOS algorithm for Monte Carlo simulation of the solutions of the Yukawa and the Helmholtz partial differential equations (PDEs was developed by using the Duffin correspondence. In this paper, we investigate the foundations behind the algorithm for the case of the Yukawa PDE. We study the panharmonic measure, which is a generalization of the harmonic measure for the Yukawa PDE. We show that there are natural stochastic definitions for the panharmonic measure in terms of the Brownian motion and that the harmonic and the panharmonic measures are all mutually equivalent. Furthermore, we calculate their Radon–Nikodym derivatives explicitly for some balls, which is a key result behind the WOS algorithm.

  7. The evaporative fraction as a measure of surface energy partitioning

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, W.E. [Pacific Northwest Lab., Richland, WA (United States); Cuenca, R.H. [Oregon State Univ., Corvallis, OR (United States)

    1990-12-31

    The evaporative fraction is a ratio that expresses the proportion of turbulent flux energy over land surfaces devoted to evaporation and transpiration (evapotranspiration). It has been used to characterize the energy partition over land surfaces and has potential for inferring daily energy balance information based on mid-day remote sensing measurements. The HAPEX-MOBILHY program`s SAMER system provided surface energy balance data over a range of agricultural crops and soil types. The databases from this large-scale field experiment was analyzed for the purpose of studying the behavior and daylight stability of the evaporative fraction in both ideal and general meteorological conditions. Strong linear relations were found to exist between the mid-day evaporative fraction and the daylight mean evaporative fraction. Statistical tests however rejected the hypothesis that the two quantities were equal. The relations between the evaporative fraction and the surface soil moisture as well as soil moisture in the complete vegetation root zone were also explored.

  8. The evaporative fraction as a measure of surface energy partitioning

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, W.E. (Pacific Northwest Lab., Richland, WA (United States)); Cuenca, R.H. (Oregon State Univ., Corvallis, OR (United States))

    1990-01-01

    The evaporative fraction is a ratio that expresses the proportion of turbulent flux energy over land surfaces devoted to evaporation and transpiration (evapotranspiration). It has been used to characterize the energy partition over land surfaces and has potential for inferring daily energy balance information based on mid-day remote sensing measurements. The HAPEX-MOBILHY program's SAMER system provided surface energy balance data over a range of agricultural crops and soil types. The databases from this large-scale field experiment was analyzed for the purpose of studying the behavior and daylight stability of the evaporative fraction in both ideal and general meteorological conditions. Strong linear relations were found to exist between the mid-day evaporative fraction and the daylight mean evaporative fraction. Statistical tests however rejected the hypothesis that the two quantities were equal. The relations between the evaporative fraction and the surface soil moisture as well as soil moisture in the complete vegetation root zone were also explored.

  9. Intermolecular potential energy surface and thermophysical properties of propane.

    Science.gov (United States)

    Hellmann, Robert

    2017-03-21

    A six-dimensional potential energy surface (PES) for the interaction of two rigid propane molecules was determined from supermolecular ab initio calculations up to the coupled cluster with single, double, and perturbative triple excitations level of theory for 9452 configurations. An analytical site-site potential function with 14 sites per molecule was fitted to the calculated interaction energies. To validate the analytical PES, the second virial coefficient and the dilute gas shear viscosity and thermal conductivity of propane were computed. The dispersion part of the potential function was slightly adjusted such that quantitative agreement with the most accurate experimental data for the second virial coefficient at room temperature was achieved. The adjusted PES yields values for the three properties that are in very good agreement with the best experimental data at all temperatures.

  10. Measuring Officer Potential Using the OER

    Science.gov (United States)

    2015-06-12

    States Army War College Press. Creswell , John . 2013. Qualitative Inquiry and Research Design : Choosing Among Five Approaches, 3rd ed. Los Angeles, CA...significance of this research study. In early 2014, the Army adopted a new officer evaluation report distinctly designed to capture the performance and...can inspire a person to reach her potential. — John C. Maxwell Purpose The purpose of this literature review is to answer the primary research

  11. Potential transportation demand management programs and measures

    Energy Technology Data Exchange (ETDEWEB)

    Litman, T. [Victoria Transport Policy Institute, Victoria, BC (Canada)

    1997-02-07

    The advantages of transportation demand management (TDM) programs were discussed. TDM includes several policies, programs and measures designed to change travel patterns. TDM programs include commute trip reductions, pricing policies, land use management strategies, and programs to support alternative modes of transportation such as public transit, carpooling, bicycling, walking and telecommuting. TDM programs are designed to reduce traffic congestion and air pollution. Some other TDM programs and measures include: enabling programs, alternative mode encouragement, driving disincentives, parking programs, marginalizing user costs, reducing automobile ownership, and land use management.

  12. ATLAS Potential for Beauty Physics Measurements

    International Nuclear Information System (INIS)

    Smizanska, M.

    2001-01-01

    The main focus of ATLAS b physics has traditionally been on the standard model. In the last few years also the aspects of new physics in B-decays has been addressed. Another new field of studies started recently is a beauty production. We give an overview of the older as well as more recent results. After an introduction outlining selected trigger and detector performance characteristics, we explain methods and goals of CP violation measurements in decay channels of B d 0 meson, physics of B s 0 system and of rare decays. Finally, the ATLAS program for beauty production measurements is presented. (author)

  13. Rocket potential measurements during electron beam injection into the ionosphere

    International Nuclear Information System (INIS)

    Gringauz, K.I.; Shutte, N.M.

    1981-01-01

    Electron flux measurements were made during pulsed injection of electron beams at a current of about 0.5 A and energy of 15 or 27 keV, using a retarding potential analyzer which was mounted on the lateral surface of the Eridan rocket during the ARAKS experiment of January 26, 1975. The general character of the retardation curves was found to be the same regardless of the electron injection energy, and regardless of the fact whether the plasma generator, injecting quasineutral cesium plasma with an ion current of about 10 A, was switched on. A sharp current increase in the interval between 10 to the -7th and 10 to the -6th A was observed with a decrease of the retarding potential. The rocket potential did not exceed approximately 150 V at about 130 to 190 km, and decreased to 20 V near 100 km. This was explained by the formation of a highly conducting region near the rocket, which was formed via intense plasma waves generated by the beam. Measurements of electron fluxes with energies of 1 to 3 keV agree well with estimates based on the beam plasma discharge theory

  14. The prediction of BRDFs from surface profile measurements

    International Nuclear Information System (INIS)

    Church, E.L.; Takacs, P.Z.; Leonard, T.A.

    1989-01-01

    This paper discusses methods of predicting the BRDF of smooth surfaces from profile measurements of their surface finish. The conversion of optical profile data to the BRDF at the same wavelength is essentially independent of scattering models, while the conversion of mechanical measurements, and wavelength scaling in general, are model dependent. Procedures are illustrated for several surfaces, including two from the recent HeNe BRDF round robin, and results are compared with measured data. Reasonable agreement is found except for surfaces which involve significant scattering from isolated surface defects which are poorly sampled in the profile data

  15. A new fiber optic sensor for inner surface roughness measurement

    Science.gov (United States)

    Xu, Xiaomei; Liu, Shoubin; Hu, Hong

    2009-11-01

    In order to measure inner surface roughness of small holes nondestructively, a new fiber optic sensor is researched and developed. Firstly, a new model for surface roughness measurement is proposed, which is based on intensity-modulated fiber optic sensors and scattering modeling of rough surfaces. Secondly, a fiber optical measurement system is designed and set up. Under the help of new techniques, the fiber optic sensor can be miniaturized. Furthermore, the use of micro prism makes the light turn 90 degree, so the inner side surface roughness of small holes can be measured. Thirdly, the fiber optic sensor is gauged by standard surface roughness specimens, and a series of measurement experiments have been done. The measurement results are compared with those obtained by TR220 Surface Roughness Instrument and Form Talysurf Laser 635, and validity of the developed fiber optic sensor is verified. Finally, precision and influence factors of the fiber optic sensor are analyzed.

  16. Physisorption of an electron in deep surface potentials off a dielectric surface

    International Nuclear Information System (INIS)

    Heinisch, R. L.; Bronold, F. X.; Fehske, H.

    2011-01-01

    We study phonon-mediated adsorption and desorption of an electron at dielectric surfaces with deep polarization-induced surface potentials where multiphonon transitions are responsible for electron energy relaxation. Focusing on multiphonon processes due to the nonlinearity of the coupling between the external electron and the acoustic bulk phonon triggering the transitions between surface states, we calculate electron desorption times for graphite, MgO, CaO, Al 2 O 3 , and SiO 2 and electron sticking coefficients for Al 2 O 3 , CaO, and SiO 2 . To reveal the kinetic stages of electron physisorption, we moreover study the time evolution of the image-state occupancy and the energy-resolved desorption flux. Depending on the potential depth and the surface temperature, we identify two generic scenarios: (i) adsorption via trapping in shallow image states followed by relaxation to the lowest image state and desorption from that state via a cascade through the second strongly bound image state in not too deep potentials, and (ii) adsorption via trapping in shallow image states but followed by a relaxation bottleneck retarding the transition to the lowest image state and desorption from that state via a one-step process to the continuum in deep potentials.

  17. Pharmaceutical and biomedical potential of surface engineered dendrimers.

    Science.gov (United States)

    Satija, Jitendra; Gupta, Umesh; Jain, Narendra Kumar

    2007-01-01

    Dendrimers are hyperbranched, globular, monodisperse, nanometric polymeric architecture, having definite molecular weight, shape, and size (which make these an inimitable and optimum carrier molecule in pharmaceutical field). Dendritic architecture is having immense potential over the other carrier systems, particularly in the field of drug delivery because of their unique properties, such as structural uniformity, high purity, efficient membrane transport, high drug pay load, targeting potential, and good colloidal, biological, and shelf stability. Despite their enormous applicability in different areas, the inherent cytotoxicity, reticuloendothelial system (RES) uptake, drug leakage, immunogenicity, and hemolytic toxicity restricted their use in clinical applications, which is primarily associated with cationic charge present on the periphery due to amine groups. To overcome this toxic nature of dendrimers, some new types of nontoxic, biocompatible, and biodegradable dendrimers have been developed (e.g., polyester dendrimer, citric acid dendrimer, arginine dendrimer, carbohydrate dendrimers, etc.). The surface engineering of parent dendrimers is graceful and convenient strategy, which not only shields the positive charge to make this carrier more biomimetic but also improves the physicochemical and biological behavior of parent dendrimers. Thus, surface modification chemistry of parent dendrimers holds promise in pharmaceutical applications (such as solubilization, improved drug encapsulation, enhanced gene transfection, sustained and controlled drug release, intracellular targeting) and in the diagnostic field. Development of multifunctional dendrimer holds greater promise toward the biomedical applications because a number of targeting ligands determine specificity in the same manner as another type of group would secure stability in biological milieu and prolonged circulation, whereas others facilitate their transport through cell membranes. Therefore, as a

  18. Inspection of freeform surfaces considering uncertainties in measurement, localization and surface reconstruction

    International Nuclear Information System (INIS)

    Mehrad, Vahid; Xue, Deyi; Gu, Peihua

    2013-01-01

    Inspection of a manufactured freeform surface can be conducted by building its surface model and comparing this manufactured surface model with the ideal design surface model and its tolerance requirement. The manufactured freeform surface model is usually achieved by obtaining measurement points on the manufactured surface, transforming these measurement points from the measurement coordinate system to the design coordinate system through localization, and reconstructing the surface model using the localized measurement points. In this research, a method was developed to estimate the locations and their variances of any selected points on the reconstructed freeform surface considering different sources of uncertainties in measurement, localization and surface reconstruction processes. In this method, first locations and variances of the localized measurement points are calculated considering uncertainties of the measurement points and uncertainties introduced in the localization processes. Then locations and variances of points on the reconstructed freeform surface are obtained considering uncertainties of the localized measurement points and uncertainties introduced in the freeform surface reconstruction process. Two case studies were developed to demonstrate how these three different uncertainty sources influence the quality of the reconstructed freeform curve and freeform surface in inspection. (paper)

  19. "Rapid Revisit" Measurements of Sea Surface Winds Using CYGNSS

    Science.gov (United States)

    Park, J.; Johnson, J. T.

    2017-12-01

    The Cyclone Global Navigation Satellite System (CYGNSS) is a space-borne GNSS-R (GNSS-Reflectometry) mission that launched December 15, 2016 for ocean surface wind speed measurements. CYGNSS includes 8 small satellites in the same LEO orbit, so that the mission provides wind speed products having unprecedented coverage both in time and space to study multi-temporal behaviors of oceanic winds. The nature of CYGNSS coverage results in some locations on Earth experiencing multiple wind speed measurements within a short period of time (a "clump" of observations in time resulting in a "rapid revisit" series of measurements). Such observations could seemingly provide indications of regions experiencing rapid changes in wind speeds, and therefore be of scientific utility. Temporally "clumped" properties of CYGNSS measurements are investigated using early CYGNSS L1/L2 measurements, and the results show that clump durations and spacing vary with latitude. For example, the duration of a clump can extend as long as a few hours at higher latitudes, with gaps between clumps ranging from 6 to as high as 12 hours depending on latitude. Examples are provided to indicate the potential of changes within a clump to produce a "rapid revisit" product for detecting convective activity. Also, we investigate detector design for identifying convective activities. Results from analyses using recent CYGNSS L2 winds will be provided in the presentation.

  20. Constructing Invariant Fairness Measures for Surfaces

    DEFF Research Database (Denmark)

    Gravesen, Jens; Ungstrup, Michael

    1998-01-01

    of the size of this vector field is used as the fairness measure on the family.Six basic 3rd order invariants satisfying two quadratic equations are defined. They form a complete set in the sense that any invariant 3rd order function can be written as a function of the six basic invariants together...

  1. Surface magnetic field measurement with magnetic shielding

    Czech Academy of Sciences Publication Activity Database

    Perevertov, Oleksiy

    2010-01-01

    Roč. 61, č. 7 (2010), 66-68 ISSN 1335-3632 Grant - others:AVČR(CZ) M100100906 Institutional research plan: CEZ:AV0Z10100520 Keywords : magnetic hysteresis * magnetic field measurement * magnetic shielding * extrapolation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.270, year: 2010

  2. Forces on nuclei moving on autoionizing molecular potential energy surfaces.

    Science.gov (United States)

    Moiseyev, Nimrod

    2017-01-14

    Autoionization of molecular systems occurs in diatomic molecules and in small biochemical systems. Quantum chemistry packages enable calculation of complex potential energy surfaces (CPESs). The imaginary part of the CPES is associated with the autoionization decay rate, which is a function of the molecular structure. Molecular dynamics simulations, within the framework of the Born-Oppenheimer approximation, require the definition of a force field. The ability to calculate the forces on the nuclei in bio-systems when autoionization takes place seems to rely on an understanding of radiative damages in RNA and DNA arising from the release of slow moving electrons which have long de Broglie wavelengths. This work addresses calculation of the real forces on the nuclei moving on the CPES. By using the transformation of the time-dependent Schrödinger equation, previously used by Madelung, we proved that the classical forces on nuclei moving on the CPES correlated with the gradient of the real part of the CPES. It was proved that the force on the nuclei of the metastable molecules is time independent although the probability to detect metastable molecules exponentially decays. The classical force is obtained from the transformed Schrödinger equation when ℏ=0 and the Schrödinger equation is reduced to the classical (Newtonian) equations of motion. The forces on the nuclei regardless on what potential energy surface they move (parent CPES or product real PESs) vary in time due to the autoionization process.

  3. Radioactivity Measurements on Glazed Ceramic Surfaces

    OpenAIRE

    Hobbs, Thomas G.

    2000-01-01

    A variety of commonly available household and industrial ceramic items and some specialty glass materials were assayed by alpha pulse counting and ion chamber voltage measurements for radioactivity concentrations. Identification of radionuclides in some of the items was performed by gamma spectroscopy. The samples included tableware, construction tiles and decorative tiles, figurines, and other products with a clay based composition. The concentrations of radioactivity ranged from near backgr...

  4. Grain size measurements by ultrasonic Rayleigh surface waves

    International Nuclear Information System (INIS)

    Palanichamy, P.; Jayakumar, T.

    1996-01-01

    The use of Rayleigh surface waves to determine average grain size nondestructively in an austenitic stainless steel AISI type 316 stainless is discussed. Two commercial type 4MHz frequency surface wave transducers, one as transmitter and the other as receiver were employed for the measurement of surface wave amplitudes. Relative amplitudes of the Rayleigh surface waves were correlated with the metallographically obtained grain sizes. Results indicate that surface/sub-surface average grain sizes of AISI type 316 austenitic stainless steel can be estimated with a confidence level of more than 80% in the grain size range 30-170 μm. (author)

  5. In situ surface roughness measurement using a laser scattering method

    Science.gov (United States)

    Tay, C. J.; Wang, S. H.; Quan, C.; Shang, H. M.

    2003-03-01

    In this paper, the design and development of an optical probe for in situ measurement of surface roughness are discussed. Based on this light scattering principle, the probe which consists of a laser diode, measuring lens and a linear photodiode array, is designed to capture the scattered light from a test surface with a relatively large scattering angle ϕ (=28°). This capability increases the measuring range and enhances repeatability of the results. The coaxial arrangement that incorporates a dual-laser beam and a constant compressed air stream renders the proposed system insensitive to movement or vibration of the test surface as well as surface conditions. Tests were conducted on workpieces which were mounted on a turning machine that operates with different cutting speeds. Test specimens which underwent different machining processes and of different surface finish were also studied. The results obtained demonstrate the feasibility of surface roughness measurement using the proposed method.

  6. Surface-wave potential for triggering tectonic (nonvolcanic) tremor

    Science.gov (United States)

    Hill, D.P.

    2010-01-01

    Source processes commonly posed to explain instances of remote dynamic triggering of tectonic (nonvolcanic) tremor by surface waves include frictional failure and various modes of fluid activation. The relative potential for Love- and Rayleigh-wave dynamic stresses to trigger tectonic tremor through failure on critically stressed thrust and vertical strike-slip faults under the Coulomb-Griffith failure criteria as a function of incidence angle is anticorrelated over the 15- to 30-km-depth range that hosts tectonic tremor. Love-wave potential is high for strike-parallel incidence on low-angle reverse faults and null for strike-normal incidence; the opposite holds for Rayleigh waves. Love-wave potential is high for both strike-parallel and strike-normal incidence on vertical, strike-slip faults and minimal for ~45?? incidence angles. The opposite holds for Rayleigh waves. This pattern is consistent with documented instances of tremor triggered by Love waves incident on the Cascadia mega-thrust and the San Andreas fault (SAF) in central California resulting from shear failure on weak faults (apparent friction, ????? 0.2). However, documented instances of tremor triggered by surface waves with strike-parallel incidence along the Nankai megathrust beneath Shikoku, Japan, is associated primarily with Rayleigh waves. This is consistent with the tremor bursts resulting from mixed-mode failure (crack opening and shear failure) facilitated by near-lithostatic ambient pore pressure, low differential stress, with a moderate friction coefficient (?? ~ 0.6) on the Nankai subduction interface. Rayleigh-wave dilatational stress is relatively weak at tectonic tremor source depths and seems unlikely to contribute significantly to the triggering process, except perhaps for an indirect role on the SAF in sustaining tremor into the Rayleigh-wave coda that was initially triggered by Love waves.

  7. Spatial distribution of potential near surface moisture flux at Yucca Mountain

    International Nuclear Information System (INIS)

    Flint, A.L.; Flint, L.E.

    1994-01-01

    An estimate of the areal distribution of present-day surface liquid moisture flux at Yucca Mountain was made using field measured water contents and laboratory measured rock properties. Using available data for physical and hydrologic properties (porosity, saturated hydraulic conductivity, moisture retention functions) of the volcanic rocks, surface lithologic units that are hydrologically similar were delineated. Moisture retention and relative permeability functions were assigned to each surface unit based on the similarity of the mean porosity and saturated hydraulic conductivity of the surface unit to laboratory samples of the same lithology. The potential flux into the mountain was estimated for each surface hydrologic unit using the mean saturated hydraulic conductivity for each unit and assuming all matrix flow. Using measured moisture profiles for each of the surface units, estimates were made of the depth at which seasonal fluctuations diminish and steady state downward flux conditions are likely to exist. The hydrologic properties at that depth were used with the current relative saturation of the tuff, to estimate flux as the unsaturated hydraulic conductivity. This method assumes a unit gradient. The range in estimated flux was 0.02 mm/yr for the welded Tiva Canyon to 13.4 mm/yr for the nonwelded Paintbrush Tuff. The areally averaged flux was 1.4 mm/yr. The major zones of high flux occur to the north of the potential repository boundary where the nonwelded tuffs are exposed in the major drainages

  8. Spatial distribution of potential near surface moisture flux at Yucca Mountain

    International Nuclear Information System (INIS)

    Flint, A.L.; Flint, L.E.

    1994-01-01

    An estimate of the areal distribution of present-day surface liquid moisture flux at Yucca Mountain was made using field measured water contents and laboratory measured rock properties. Using available data for physical and hydrologic properties (porosity, saturated hydraulic conductivity moisture retention functions) of the volcanic rocks, surface lithologic units that are hydrologically similar were delineated. Moisture retention and relative permeability functions were assigned to each surface unit based on the similarity of the mean porosity and saturated hydraulic conductivity of the surface unit to laboratory samples of the same lithology. The potential flux into the mountain was estimated for each surface hydrologic unit using the mean saturated hydraulic conductivity for each unit and assuming all matrix flow. Using measured moisture profiles for each of the surface units, estimates were made of the depth at which seasonal fluctuations diminish and steady state downward flux conditions are likely to exist. The hydrologic properties at that depth were used with the current relative saturation of the tuff, to estimate flux as the unsaturated hydraulic conductivity. This method assumes a unit gradient. The range in estimated flux was 0.02 mm/yr for the welded Tiva Canyon to 13.4 mm/yr for the nonwelded Paintbrush Tuff. The areally averaged flux was 1.4 mm/yr. The major zones of high flux occur to the north of the potential repository boundary where the nonwelded tuffs are exposed in the major drainages

  9. Surface potential of methyl isobutyl carbinol adsorption layer at the air/water interface.

    Science.gov (United States)

    Phan, Chi M; Nakahara, Hiromichi; Shibata, Osamu; Moroi, Yoshikiyo; Le, Thu N; Ang, Ha M

    2012-01-26

    The surface potential (ΔV) and surface tension (γ) of MIBC (methyl isobutyl carbinol) were measured on the subphase of pure water and electrolyte solutions (NaCl at 0.02 and 2 M). In contrast to ionic surfactants, it was found that surface potential gradually increased with MIBC concentration. The ΔV curves were strongly influenced by the presence of NaCl. The available model in literature, in which surface potential is linearly proportional to surface excess, failed to describe the experimental data. Consequently, a new model, employing a partial charge of alcohol adsorption layer, was proposed. The new model predicted the experimental data consistently for MIBC in different NaCl solutions. However, the model required additional information for ionic impurity to predict adsorption in the absence of electrolyte. Such inclusion of impurities is, however, unnecessary for industrial applications. The modeling results successfully quantify the influence of electrolytes on surface potential of MIBC, which is critical for froth stability.

  10. Image potential resonances of the aluminum (100) surface; Bildpotentialresonanzen der Aluminium-(100)-Oberflaeche

    Energy Technology Data Exchange (ETDEWEB)

    Winter, Matthias

    2011-07-08

    Image-potential resonances on the (100) surface of pure Aluminum are investigated experimentally and theoretically. The experiments are conducted both energy- and time-resolved using the method of two-photon photoemission spectroscopy. The main attention of the theoretical examination and extensive numerical calculations is devoted to the interaction between surface and bulk states. Image-potential resonances on Al(100) are a system in which a complete series of discrete Rydberg states strongly couples to a continuum of states. As a simple metal it also provides a good opportunity to test theoretical models of the structure of the potential at metal surfaces. This work represents the first high-resolution investigation of image-potential resonances with such strong resonance character. For the first time, it is demonstrated experimentally that isolated image-potential resonances exist on an Aluminum surface. On the (100) surface of Aluminum the second through fifth image-potential resonance are resolved and both, their energies and lifetimes are measured. The binding energies of the image-potential resonances form a Rydberg series of states {epsilon}{sub n}=-(0,85 eV)/((n+a){sup 2}). Within the accuracy of the measurement it is not necessary to introduce a quantum defect a (a=0.022{+-}0.035). Using angle-resolved two-photon photoemission spectroscopy the effective mass of electrons in the second image-potential resonance is measured to 1.01{+-}0.11 electron masses. The lifetimes of the resonances increase as {tau}{sub n} = (1.0{+-}0.2)fs.n{sup 3} starting from n=2. Calculations using the density matrix formalism show that the experimentally observed lifetimes can be explained well by electrons decaying into the bulk. The effect of resonance trapping leads to extended lifetimes in the process. Contrary to common theoretical models of image-potential states at metal surfaces the first image-potential resonance cannot be observed in two-photon photoemission on Al(100

  11. Development of material measures for performance verifying surface topography measuring instruments

    International Nuclear Information System (INIS)

    Leach, Richard; Giusca, Claudiu; Rickens, Kai; Riemer, Oltmann; Rubert, Paul

    2014-01-01

    The development of two irregular-geometry material measures for performance verifying surface topography measuring instruments is described. The material measures are designed to be used to performance verify tactile and optical areal surface topography measuring instruments. The manufacture of the material measures using diamond turning followed by nickel electroforming is described in detail. Measurement results are then obtained using a traceable stylus instrument and a commercial coherence scanning interferometer, and the results are shown to agree to within the measurement uncertainties. The material measures are now commercially available as part of a suite of material measures aimed at the calibration and performance verification of areal surface topography measuring instruments

  12. Entrance surface dose measurements in mammography using thermoluminescence technique

    International Nuclear Information System (INIS)

    Rivera, T.; Vega C, H.R.; Manzanares A, E; Azorin, J.; Gonzalez, P.R.

    2007-01-01

    Full text: Of the various techniques that can be used for personnel dosimetry, thermoluminescence dosimetry (TLD) has emerged as a superior technique due to its manifold advantages over other methods of dose estimation. Various phosphors have been therefore investigated regarding their suitability for dosimetry. In this paper, a dosimetry system based on thermally stimulated luminescence (TSL) from zirconium oxide phosphors embedded in polytetrafluorethylene (ZrO 2 +PTFE) was developed for entrance surface doses (ES) measurements in mammography. Small ZrO 2 pellets of 5 mm in diameter and 0.8 mm in thickness were used. The reproducibility of measurements and linearity of ZrO 2 were also studied. The results were compared with those obtained from LiF:Mg,Cu,P usually used for the determination of absorbed dose in mammography. Measurements both per unit air kerma and In vivo were performed using a mammography unit model DMR (General Electric). The results showed that ZrO 2 TLDs can be used for the same X-ray dosimetry applications as LiF:Mg,Cu,P, with each type having the disadvantage of a response dependent on energy, particularly at low energies. These results indicate a considerable potential for use in routine control and In vivo ES measurements in mammography. (Author)

  13. Guided selective deposition of nanoparticles by tuning of the surface potential

    Science.gov (United States)

    Eklöf, J.; Stolaś, A.; Herzberg, M.; Pekkari, A.; Tebikachew, B.; Gschneidtner, T.; Lara-Avila, S.; Hassenkam, T.; Moth-Poulsen, K.

    2017-07-01

    Guided deposition of nanoparticles onto different substrates is of great importance for a variety of applications such as biosensing, targeted cancer therapy, anti-bacterial coatings and single molecular electronics. It is therefore important to gain an understanding of what parameters are involved in the deposition of nanoparticles. In this work we have deposited 60 nm, negatively charged, citrate stabilized gold nanoparticles onto microstructures consisting of six different materials, (vanadium (V), silicon dioxide (SiO2), gold (Au), aluminum (Al), copper (Cu) and nickel (Ni)). The samples have then been investigated by scanning electron microscopy to extract the particle density. The surface potential was calculated from the measured surface charge density maps measured by atomic force microscopy while the samples were submerged in a KCl water solution. These values were compared with literature values of the isoelectric points (IEP) of different oxides formed on the metals in an ambient environment. According to measurements, Al had the highest surface potential followed by Ni and Cu. The same trend was observed for the nanoparticle densities. No particles were found on V, SiO2 and Au. The literature values of the IEP showed a different trend compared to the surface potential measurements concluding that IEP is not a reliable parameter for the prediction of NP deposition. Contribution to the Focus Issue Self-assemblies of Inorganic and Organic Nanomaterials edited by Marie-Paule Pileni.

  14. Determination of Surface Potential and Electrical Double-Layer Structure at the Aqueous Electrolyte-Nanoparticle Interface

    Directory of Open Access Journals (Sweden)

    Matthew A. Brown

    2016-01-01

    Full Text Available The structure of the electrical double layer has been debated for well over a century, since it mediates colloidal interactions, regulates surface structure, controls reactivity, sets capacitance, and represents the central element of electrochemical supercapacitors. The surface potential of such surfaces generally exceeds the electrokinetic potential, often substantially. Traditionally, a Stern layer of nonspecifically adsorbed ions has been invoked to rationalize the difference between these two potentials; however, the inability to directly measure the surface potential of dispersed systems has rendered quantitative measurements of the Stern layer potential, and other quantities associated with the outer Helmholtz plane, impossible. Here, we use x-ray photoelectron spectroscopy from a liquid microjet to measure the absolute surface potentials of silica nanoparticles dispersed in aqueous electrolytes. We quantitatively determine the impact of specific cations (Li^{+}, Na^{+}, K^{+}, and Cs^{+} in chloride electrolytes on the surface potential, the location of the shear plane, and the capacitance of the Stern layer. We find that the magnitude of the surface potential increases linearly with the hydrated-cation radius. Interpreting our data using the simplest assumptions and most straightforward understanding of Gouy-Chapman-Stern theory reveals a Stern layer whose thickness corresponds to a single layer of water molecules hydrating the silica surface, plus the radius of the hydrated cation. These results subject electrical double-layer theories to direct and falsifiable tests to reveal a physically intuitive and quantitatively verified picture of the Stern layer that is consistent across multiple electrolytes and solution conditions.

  15. Determination of Surface Potential and Electrical Double-Layer Structure at the Aqueous Electrolyte-Nanoparticle Interface

    Science.gov (United States)

    Brown, Matthew A.; Abbas, Zareen; Kleibert, Armin; Green, Richard G.; Goel, Alok; May, Sylvio; Squires, Todd M.

    2016-01-01

    The structure of the electrical double layer has been debated for well over a century, since it mediates colloidal interactions, regulates surface structure, controls reactivity, sets capacitance, and represents the central element of electrochemical supercapacitors. The surface potential of such surfaces generally exceeds the electrokinetic potential, often substantially. Traditionally, a Stern layer of nonspecifically adsorbed ions has been invoked to rationalize the difference between these two potentials; however, the inability to directly measure the surface potential of dispersed systems has rendered quantitative measurements of the Stern layer potential, and other quantities associated with the outer Helmholtz plane, impossible. Here, we use x-ray photoelectron spectroscopy from a liquid microjet to measure the absolute surface potentials of silica nanoparticles dispersed in aqueous electrolytes. We quantitatively determine the impact of specific cations (Li+ , Na+ , K+ , and Cs+ ) in chloride electrolytes on the surface potential, the location of the shear plane, and the capacitance of the Stern layer. We find that the magnitude of the surface potential increases linearly with the hydrated-cation radius. Interpreting our data using the simplest assumptions and most straightforward understanding of Gouy-Chapman-Stern theory reveals a Stern layer whose thickness corresponds to a single layer of water molecules hydrating the silica surface, plus the radius of the hydrated cation. These results subject electrical double-layer theories to direct and falsifiable tests to reveal a physically intuitive and quantitatively verified picture of the Stern layer that is consistent across multiple electrolytes and solution conditions.

  16. Fast Plasma Potential Measurements Using an Emissive Probe

    Science.gov (United States)

    Ready, Amanda; Clark, Michael; Endrizzi, Douglass; Forest, Cary; Peterson, Ethan

    2017-10-01

    A heated emissive probe was developed for making direct plasma potential (Vp) measurements in rapidly fluctuating plasmas. Previous experiments on the Big Red Ball (BRB) were hindered by sudden potential drops, making Langmuir measurements of the plasma potential difficult. DC heating of a tungsten filament to emission allowed for fast (4 MHz) floating potential measurements that closely matched Vp. Two BRB experiments currently use the emissive probe. The investigation of unmagnetized, collisionless shocks used plasma potential measurements to study the sub-structure of strong plasma shocks. A separate investigation of emulated magnetospheres in laboratory plasmas used the plasma potential to map the equilibria and instabilities in the electric field of such structures. Results showing electric field measurements and comparison with cold Langmuir measurements will be presented. Future plans for probe modifications and applications to other experiments on the BRB will also be shown.

  17. Two-dimensional potential and charge distributions of positive surface streamer

    International Nuclear Information System (INIS)

    Tanaka, Daiki; Matsuoka, Shigeyasu; Kumada, Akiko; Hidaka, Kunihiko

    2009-01-01

    Information on the potential and the field profile along a surface discharge is required for quantitatively discussing and clarifying the propagation mechanism. The sensing technique with a Pockels crystal has been developed for directly measuring the potential and electric field distribution on a dielectric material. In this paper, the Pockels sensing system consists of a pulse laser and a CCD camera for measuring the instantaneous two-dimensional potential distribution on a 25.4 mm square area with a 50 μm sampling pitch. The temporal resolution is 3.2 ns which is determined by the pulse width of the laser emission. The transient change in the potential distribution of a positive surface streamer propagating in atmospheric air is measured with this system. The electric field and the charge distributions are also calculated from the measured potential profile. The propagating direction component of the electric field near the tip of the propagating streamer reaches 3 kV mm -1 . When the streamer stops, the potential distribution along a streamer forms an almost linear profile with the distance from the electrode, and its gradient is about 0.5 kV mm -1 .

  18. Potential dependent adhesion forces on bare and underpotential deposition modified electrode surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Serafin, J.M.; Hsieh, S.J.; Monahan, J.; Gewirth, A.A. [Univ. of Illinois, Urbana, IL (United States)

    1998-12-03

    Adhesion force measurements are used to determine the potential dependence of the force of adhesion between a Si{sub 3}N{sub 4} cantilever and a Au(111) surface modified by the underpotential deposition (upd) of Bi or Cu in acid solution or by oxide formation. The measured work of adhesion is near zero for most of the potential region examined in Bi upd but rises after the formation of a full Bi monolayer. The work of adhesion is high at positive potentials for Cu upd but then decreases as the Cu partial and full monolayers are formed. The work of adhesion is low in the oxide region on Au(111) but rises following the sulfate disordering transition at 1.1 V vs NHE. These results are interpreted in terms of the degree of solvent order on the electrode surface.

  19. The electrical double layer on gold probed by electrokinetic and surface force measurements

    NARCIS (Netherlands)

    Giesbers, M.; Kleijn, J.M.; Cohen Stuart, M.A.

    2002-01-01

    Gold surfaces, obtained by vacuum deposition of 15-nm gold films on glass and silica wafers, were studied in aqueous solutions by streaming potential measurements and colloidal-probe AFM force measurements. In the force measurements both a bare and a gold-coated silica particle (6 m in diameter)

  20. Radioactivity Measurements on Glazed Ceramic Surfaces.

    Science.gov (United States)

    Hobbs, T G

    2000-01-01

    A variety of commonly available household and industrial ceramic items and some specialty glass materials were assayed by alpha pulse counting and ion chamber voltage measurements for radioactivity concentrations. Identification of radionuclides in some of the items was performed by gamma spectroscopy. The samples included tableware, construction tiles and decorative tiles, figurines, and other products with a clay based composition. The concentrations of radioactivity ranged from near background to about four orders of magnitude higher. Almost every nuclide identification test demonstrated some radioactivity content from one or more of the naturally occurring radionuclide series of thorium or uranium. The glazes seemed to contribute most of the activity, although a sample of unglazed pottery greenware showed some activity. Samples of glazing paints and samples of deliberately doped glass from the World War II era were included in the test, as was a section of foam filled poster board. A glass disc with known (232)Th radioactivity concentration was cast for use as a calibration source. The results from the two assay methods are compared, and a projection of sensitivity from larger electret ion chamber devices is presented.

  1. Measurement of the first ionization potential of lawrencium, element 103.

    Science.gov (United States)

    Sato, T K; Asai, M; Borschevsky, A; Stora, T; Sato, N; Kaneya, Y; Tsukada, K; Düllmann, Ch E; Eberhardt, K; Eliav, E; Ichikawa, S; Kaldor, U; Kratz, J V; Miyashita, S; Nagame, Y; Ooe, K; Osa, A; Renisch, D; Runke, J; Schädel, M; Thörle-Pospiech, P; Toyoshima, A; Trautmann, N

    2015-04-09

    The chemical properties of an element are primarily governed by the configuration of electrons in the valence shell. Relativistic effects influence the electronic structure of heavy elements in the sixth row of the periodic table, and these effects increase dramatically in the seventh row--including the actinides--even affecting ground-state configurations. Atomic s and p1/2 orbitals are stabilized by relativistic effects, whereas p3/2, d and f orbitals are destabilized, so that ground-state configurations of heavy elements may differ from those of lighter elements in the same group. The first ionization potential (IP1) is a measure of the energy required to remove one valence electron from a neutral atom, and is an atomic property that reflects the outermost electronic configuration. Precise and accurate experimental determination of IP1 gives information on the binding energy of valence electrons, and also, therefore, on the degree of relativistic stabilization. However, such measurements are hampered by the difficulty in obtaining the heaviest elements on scales of more than one atom at a time. Here we report that the experimentally obtained IP1 of the heaviest actinide, lawrencium (Lr, atomic number 103), is 4.96(+0.08)(-0.07) electronvolts. The IP1 of Lr was measured with (256)Lr (half-life 27 seconds) using an efficient surface ion-source and a radioisotope detection system coupled to a mass separator. The measured IP1 is in excellent agreement with the value of 4.963(15) electronvolts predicted here by state-of-the-art relativistic calculations. The present work provides a reliable benchmark for theoretical calculations and also opens the way for IP1 measurements of superheavy elements (that is, transactinides) on an atom-at-a-time scale.

  2. Compensation of the skin effect in low-frequency potential drop measurements

    OpenAIRE

    Corcoran, J; Nagy, PB

    2016-01-01

    Potential drop measurements are routinely used in the non-destructive evaluation of component integrity. Potential drop measurements use either direct current (DC) or alternating current (AC), the latter will have superior noise performance due to the ability to perform phase sensitive detection and the reduction of flicker noise. AC measurements are however subject to the skin effect where the current is electromagnetically constricted to the surface of the component. Unfortunately, the skin...

  3. Stabilized quasi-Newton optimization of noisy potential energy surfaces

    International Nuclear Information System (INIS)

    Schaefer, Bastian; Goedecker, Stefan; Alireza Ghasemi, S.; Roy, Shantanu

    2015-01-01

    Optimizations of atomic positions belong to the most commonly performed tasks in electronic structure calculations. Many simulations like global minimum searches or characterizations of chemical reactions require performing hundreds or thousands of minimizations or saddle computations. To automatize these tasks, optimization algorithms must not only be efficient but also very reliable. Unfortunately, computational noise in forces and energies is inherent to electronic structure codes. This computational noise poses a severe problem to the stability of efficient optimization methods like the limited-memory Broyden–Fletcher–Goldfarb–Shanno algorithm. We here present a technique that allows obtaining significant curvature information of noisy potential energy surfaces. We use this technique to construct both, a stabilized quasi-Newton minimization method and a stabilized quasi-Newton saddle finding approach. We demonstrate with the help of benchmarks that both the minimizer and the saddle finding approach are superior to comparable existing methods

  4. Stabilized quasi-Newton optimization of noisy potential energy surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Bastian; Goedecker, Stefan, E-mail: stefan.goedecker@unibas.ch [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Alireza Ghasemi, S. [Institute for Advanced Studies in Basic Sciences, P.O. Box 45195-1159, IR-Zanjan (Iran, Islamic Republic of); Roy, Shantanu [Computational and Systems Biology, Biozentrum, University of Basel, CH-4056 Basel (Switzerland)

    2015-01-21

    Optimizations of atomic positions belong to the most commonly performed tasks in electronic structure calculations. Many simulations like global minimum searches or characterizations of chemical reactions require performing hundreds or thousands of minimizations or saddle computations. To automatize these tasks, optimization algorithms must not only be efficient but also very reliable. Unfortunately, computational noise in forces and energies is inherent to electronic structure codes. This computational noise poses a severe problem to the stability of efficient optimization methods like the limited-memory Broyden–Fletcher–Goldfarb–Shanno algorithm. We here present a technique that allows obtaining significant curvature information of noisy potential energy surfaces. We use this technique to construct both, a stabilized quasi-Newton minimization method and a stabilized quasi-Newton saddle finding approach. We demonstrate with the help of benchmarks that both the minimizer and the saddle finding approach are superior to comparable existing methods.

  5. An AFM-based pit-measuring method for indirect measurements of cell-surface membrane vesicles

    International Nuclear Information System (INIS)

    Zhang, Xiaojun; Chen, Yuan; Chen, Yong

    2014-01-01

    Highlights: • Air drying induced the transformation of cell-surface membrane vesicles into pits. • An AFM-based pit-measuring method was developed to measure cell-surface vesicles. • Our method detected at least two populations of cell-surface membrane vesicles. - Abstract: Circulating membrane vesicles, which are shed from many cell types, have multiple functions and have been correlated with many diseases. Although circulating membrane vesicles have been extensively characterized, the status of cell-surface membrane vesicles prior to their release is less understood due to the lack of effective measurement methods. Recently, as a powerful, micro- or nano-scale imaging tool, atomic force microscopy (AFM) has been applied in measuring circulating membrane vesicles. However, it seems very difficult for AFM to directly image/identify and measure cell-bound membrane vesicles due to the similarity of surface morphology between membrane vesicles and cell surfaces. Therefore, until now no AFM studies on cell-surface membrane vesicles have been reported. In this study, we found that air drying can induce the transformation of most cell-surface membrane vesicles into pits that are more readily detectable by AFM. Based on this, we developed an AFM-based pit-measuring method and, for the first time, used AFM to indirectly measure cell-surface membrane vesicles on cultured endothelial cells. Using this approach, we observed and quantitatively measured at least two populations of cell-surface membrane vesicles, a nanoscale population (<500 nm in diameter peaking at ∼250 nm) and a microscale population (from 500 nm to ∼2 μm peaking at ∼0.8 μm), whereas confocal microscopy only detected the microscale population. The AFM-based pit-measuring method is potentially useful for studying cell-surface membrane vesicles and for investigating the mechanisms of membrane vesicle formation/release

  6. SGP Cloud and Land Surface Interaction Campaign (CLASIC): Measurement Platforms

    Energy Technology Data Exchange (ETDEWEB)

    MA Miller; R Avissar; LK Berg; SA Edgerton; ML Fischer; TJ Jackson; B. Kustas; PJ Lamb; G McFarquhar; Q Min; B Schmid; MS Torn; DD Tuner

    2007-06-01

    The Cloud and Land Surface Interaction Campaign (CLASIC) will be conducted from June 8 to June 30, 2007, at the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) Southern Great Plains (SGP) site. Data will be collected using eight aircraft equipped with a variety of specialized sensors, four specially instrumented surface sites, and two prototype surface radar systems. The architecture of CLASIC includes a high-altitude surveillance aircraft and enhanced vertical thermodynamic and wind profile measurements that will characterize the synoptic scale structure of the clouds and the land surface within the ACRF SGP site. Mesoscale and microscale structures will be sampled with a variety of aircraft, surface, and radar observations. An overview of the measurement platforms that will be used during the CLASIC are described in this report. The coordination of measurements, especially as it relates to aircraft flight plans, will be discussed in the CLASIC Implementation Plan.

  7. The Lunar Potential Determination Using Apollo-Era Data and Modern Measurements and Models

    Science.gov (United States)

    Collier, Michael R.; Farrell, William M.; Espley, Jared; Webb, Phillip; Stubbs, Timothy J.; Webb, Phillip; Hills, H. Kent; Delory, Greg

    2008-01-01

    Since the Apollo era the electric potential of the Moon has been a subject of interest and debate. Deployed by three Apollo missions, Apollo 12, Apollo 14 and Apollo 15, the Suprathermal Ion Detector Experiment (SIDE) determined the sunlit lunar surface potential to be about +10 Volts using the energy spectra of lunar ionospheric thermal ions accelerated toward the Moon. More recently, the Lunar Prospector (LP) Electron Reflectometer used electron distributions to infer negative lunar surface potentials, primarily in shadow. We will present initial results from a study to combine lunar surface potential measurements from both SIDE and the LP/Electron Reflectometer to calibrate an advanced model of lunar surface charging which includes effects from the plasma environment, photoemission, secondaries ejected by ion impact onto the lunar surface, and the lunar wake created downstream by the solar wind-lunar interaction.

  8. Measurements of radon progeny activity on typical indoor surfaces

    International Nuclear Information System (INIS)

    Knutson, E.O.; Gogolak, C.V.; Klemic, G.

    1992-01-01

    A number of studies aimed at defining how well radon progeny on surfaces can be measured, information that is needed in order to test physical/mathematical models governing indoor radon progeny behaviour, are described. One experiment compared the decomposition on to different surfaces. Only relatively small differences were found among metal, filter paper, broadcloth, corduroy fabric, vinyl wallpaper, glass, and latex paint, but polyethylene film collected two to four times as much as the others, due most likely to electrostatic charge on the plastic surface. Another experiment compared the gamma and gross alpha count methods of measuring surface activity for metal, filter paper, broadcloth and corduroy surfaces. No difference for the surfaces tested was found from which it is concluded that, even for rougher surfaces, progeny atoms deposit mainly on the outer layers. A final experiment compared in situ and surrogate-surface methods for measuring surface deposition. For most tests, the two methods agreed within 30%, and the average ratio was not significantly different from unity. 210 Po is a complication in the in situ method. An unexpected location effect was found in the experiments conducted in houses with high radon concentrations: the deposition on the ceiling was higher than on the surfaces. (author)

  9. Direct Measurement of the Surface Energy of Graphene.

    Science.gov (United States)

    van Engers, Christian D; Cousens, Nico E A; Babenko, Vitaliy; Britton, Jude; Zappone, Bruno; Grobert, Nicole; Perkin, Susan

    2017-06-14

    Graphene produced by chemical vapor deposition (CVD) is a promising candidate for implementing graphene in a range of technologies. In most device configurations, one side of the graphene is supported by a solid substrate, wheras the other side is in contact with a medium of interest, such as a liquid or other two-dimensional material within a van der Waals stack. In such devices, graphene interacts on both faces via noncovalent interactions and therefore surface energies are key parameters for device fabrication and operation. In this work, we directly measured adhesive forces and surface energies of CVD-grown graphene in dry nitrogen, water, and sodium cholate using a modified surface force balance. For this, we fabricated large (∼1 cm 2 ) and clean graphene-coated surfaces with smooth topography at both macro- and nanoscales. By bringing two such surfaces into contact and measuring the force required to separate them, we measured the surface energy of single-layer graphene in dry nitrogen to be 115 ± 4 mJ/m 2 , which was similar to that of few-layer graphene (119 ± 3 mJ/m 2 ). In water and sodium cholate, we measured interfacial energies of 83 ± 7 and 29 ± 6 mJ/m 2 , respectively. Our work provides the first direct measurement of graphene surface energy and is expected to have an impact both on the development of graphene-based devices and contribute to the fundamental understanding of surface interactions.

  10. Investigating transfer gate potential barrier by feed-forward effect measurement

    NARCIS (Netherlands)

    Xu, Y.; Ge, X.; Theuwissen, A.J.P.

    2015-01-01

    In a 4T pixel, the transfer gate (TG) “OFF” surface potential is one of the important parameters, which determines the pinned photodiode (PPD) full well capacity. The feed-forward effect measurement is a powerful tool to characterize the relationship of the PPD injection potential and the

  11. Automatic Measurement of Low Level Contamination on Concrete Surfaces

    International Nuclear Information System (INIS)

    Tachibana, M.; Itoh, H.; Shimada, T.; Yanagihara, S.

    2002-01-01

    Automatic measurement of radioactivity is necessary for considering cost effectiveness in final radiological survey of building structures in decommissioning nuclear facilities. The RAPID (radiation measuring pilot device for surface contamination) was developed to be applied to automatic measurement of low level contamination on concrete surfaces. The RAPID has a capability to measure contamination with detection limit of 0.14 Bq/cm2 for 60Co in 30 seconds of measurement time and its efficiency is evaluated to be 5 m2/h in a normal measurement option. It was confirmed that low level contamination on concrete surfaces could be surveyed by the RAPID efficiently compared with direct measurement by workers through its actual application

  12. Measurement of Dynamic Friction Coefficient on the Irregular Free Surface

    International Nuclear Information System (INIS)

    Yeom, S. H.; Seo, K. S.; Lee, J. H.; Lee, K. H.

    2007-01-01

    A spent fuel storage cask must be estimated for a structural integrity when an earthquake occurs because it freely stands on ground surface without a restriction condition. Usually the integrity estimation for a seismic load is performed by a FEM analysis, the friction coefficient for a standing surface is an important parameter in seismic analysis when a sliding happens. When a storage cask is placed on an irregular ground surface, measuring a friction coefficient of an irregular surface is very difficult because the friction coefficient is affected by the surface condition. In this research, dynamic friction coefficients on the irregular surfaces between a concrete cylinder block and a flat concrete slab are measured with two methods by one direction actuator

  13. Measurement of near neighbor separations of surface atoms

    International Nuclear Information System (INIS)

    Cohen, P.I.

    Two techniques are being developed to measure the nearest neighbor distances of atoms at the surfaces of solids. Both measures extended fine structure in the excitation probability of core level electrons which are excited by an incident electron beam. This is an important problem because the structures of most surface systems are as yet unknown, even though the location of surface atoms is the basis for any quantitative understanding of the chemistry and physics of surfaces and interfaces. These methods would allow any laboratory to make in situ determinations of surface structure in conjunction with most other laboratory probes of surfaces. Each of these two techniques has different advantages; further, the combination of the two will increase confidence in the results by reducing systematic error in the data analysis

  14. Surface deposition measurements of the TMI-2 gross decontamination experiment

    International Nuclear Information System (INIS)

    McIssac, C.V.; Hetzer, D.C.

    1982-01-01

    In order to measure the effectiveness of the gross decontamination experiment (principally a water spray technique) performed in the TMI-2 reactor building, the Technical Information and Examination Program's Radiation and Environment personnel made surface activity measurements before and after the experiment. In conjunction with surface sampling, thermoluminescent dosimeter (TLD) and gamma spectrometry measurements were also performed to distinguish between radiation fields and contamination. The surface sampler used to collect samples from external surfaces within the reactor building is a milling tool having four major components: a 1.27-cm constant-speed drill; a drill support assembly that allows setting sample penetration depth; filter cartridges for intake air purification and sample collection; and an air pump that forces air across the surface being sampled and through the sample filter cartridge

  15. Detection of a strongly negative surface potential at Saturn's moon Hyperion.

    Science.gov (United States)

    Nordheim, T A; Jones, G H; Roussos, E; Leisner, J S; Coates, A J; Kurth, W S; Khurana, K K; Krupp, N; Dougherty, M K; Waite, J H

    2014-10-28

    On 26 September 2005, Cassini conducted its only close targeted flyby of Saturn's small, irregularly shaped moon Hyperion. Approximately 6 min before the closest approach, the electron spectrometer (ELS), part of the Cassini Plasma Spectrometer (CAPS) detected a field-aligned electron population originating from the direction of the moon's surface. Plasma wave activity detected by the Radio and Plasma Wave instrument suggests electron beam activity. A dropout in energetic electrons was observed by both CAPS-ELS and the Magnetospheric Imaging Instrument Low-Energy Magnetospheric Measurement System, indicating that the moon and the spacecraft were magnetically connected when the field-aligned electron population was observed. We show that this constitutes a remote detection of a strongly negative (∼ -200 V) surface potential on Hyperion, consistent with the predicted surface potential in regions near the solar terminator.

  16. A computer-aided surface roughness measurement system

    International Nuclear Information System (INIS)

    Hughes, F.J.; Schankula, M.H.

    1983-11-01

    A diamond stylus profilometer with computer-based data acquisitions/analysis system is being used to characterize surfaces of reactor components and materials, and to examine the effects of surface topography on thermal contact conductance. The current system is described; measurement problems and system development are discussed in general terms and possible future improvements are outlined

  17. Measuring Forces between Oxide Surfaces Using the Atomic Force Microscope

    DEFF Research Database (Denmark)

    Pedersen, Henrik Guldberg; Høj, Jakob Weiland

    1996-01-01

    The interactions between colloidal particles play a major role in processing of ceramics, especially in casting processes. With the Atomic Force Microscope (AFM) it is possible to measure the inter-action force between a small oxide particle (a few micron) and a surface as function of surface...

  18. Drop shape visualization and contact angle measurement on curved surfaces.

    Science.gov (United States)

    Guilizzoni, Manfredo

    2011-12-01

    The shape and contact angles of drops on curved surfaces is experimentally investigated. Image processing, spline fitting and numerical integration are used to extract the drop contour in a number of cross-sections. The three-dimensional surfaces which describe the surface-air and drop-air interfaces can be visualized and a simple procedure to determine the equilibrium contact angle starting from measurements on curved surfaces is proposed. Contact angles on flat surfaces serve as a reference term and a procedure to measure them is proposed. Such procedure is not as accurate as the axisymmetric drop shape analysis algorithms, but it has the advantage of requiring only a side view of the drop-surface couple and no further information. It can therefore be used also for fluids with unknown surface tension and there is no need to measure the drop volume. Examples of application of the proposed techniques for distilled water drops on gemstones confirm that they can be useful for drop shape analysis and contact angle measurement on three-dimensional sculptured surfaces. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Simulated BRDF based on measured surface topography of metal

    Science.gov (United States)

    Yang, Haiyue; Haist, Tobias; Gronle, Marc; Osten, Wolfgang

    2017-06-01

    The radiative reflective properties of a calibration standard rough surface were simulated by ray tracing and the Finite-difference time-domain (FDTD) method. The simulation results have been used to compute the reflectance distribution functions (BRDF) of metal surfaces and have been compared with experimental measurements. The experimental and simulated results are in good agreement.

  20. Measurement of grassland evaporation using a surface-layer ...

    African Journals Online (AJOL)

    Measurement of grassland evaporation using a surface-layer scintillometer. ... Water SA. Journal Home · ABOUT THIS JOURNAL · Advanced Search ... of soil heat flux and net irradiance, evaporation rates were calculated as a residual of the ...

  1. Calibration technique for the neutron surface moisture measurement system

    International Nuclear Information System (INIS)

    Watson, W.T.; Shreve, D.C.

    1996-01-01

    A technique for calibrating the response of a surface neutron moisture measurement probe to material moisture concentration has been devised. Tests to ensure that the probe will function in the expected in-tank operating environment are also outlined

  2. Surface Resistance Measurements of LHC Dipole Beam Screen Samples

    CERN Document Server

    Caspers, Friedhelm; Ruggiero, F; Tan, J; Tsutsui, H

    2000-01-01

    An estimate of the resistive losses in the LHC dipole beam screen is given from cold surface resistance measurements using the shielded pair technique. Several beam screen samples have been evaluated, with different copper coating methods, including a sample with ribbed surface envisaged to reduce electron cloud losses thanks to its low reflectivity. Experimental data, derived by a proper analysis of the measured Q-factors and including error estimates are compared with theoretical predictions of the anomalous skin effect.

  3. On $L_p$ Affine Surface Area and Curvature Measures

    OpenAIRE

    Zhao, Yiming

    2015-01-01

    The relationship between $L_p$ affine surface area and curvature measures is investigated. As a result, a new representation of the existing notion of $L_p$ affine surface area depending only on curvature measures is derived. Direct proofs of the equivalence between this new representation and those previously known are provided. The proofs show that the new representation is, in a sense, "polar" to that of Lutwak's and "dual" to that of Sch\\"utt & Werner's.

  4. An improved potential drop method for measuring and monitoring defects in structures

    International Nuclear Information System (INIS)

    Oppermann, W.; Keller, H.P.

    1991-01-01

    In its advanced form, the direct-current potential probe measuring technique is a reliable and relatively exact procedure for measuring and monitoring surface defects. In addition, there is the possibility - important for practical purposes - of measuring cracks at the inaccessible side of a component part. The improved accuracy, in particular with regard to short defects, is based on advanced measuring techniques and calibration curves determined at the electrolytical tank. (orig./DG) [de

  5. Accuracy of Surface Plate Measurements - General Purpose Software for Flatness Measurement

    NARCIS (Netherlands)

    Meijer, J.; Heuvelman, C.J.

    1990-01-01

    Flatness departures of surface plates are generally obtained from straightness measurements of lines on the surface. A computer program has been developed for on-line measurement and evaluation, based on the simultaneous coupling of measurements in all grid points. Statistical methods are used to

  6. A noncontact laser system for measuring soil surface topography

    International Nuclear Information System (INIS)

    Huang, C.; White, I.; Thwaite, E.G.; Bendeli, A.

    1988-01-01

    Soil surface topography profoundly influences runoff hydrodynamics, soil erosion, and surface retention of water. Here we describe an optical noncontact system for measuring soil surface topography. Soil elevation is measured by projecting a laser beam onto the surface and detecting the position of the interception point. The optical axis of the detection system is oriented at a small angle to the incident beam. A low-power HeNe (Helium-Neon) laser is used as the laser source, a photodiode array is used as the laser image detector and an ordinary 35-mm single lens reflex camera provides the optical system to focus the laser image onto the diode array. A wide spectrum of measurement ranges (R) and resolutions are selectable, from 1 mm to 1 m. These are determined by the laser-camera distance and angle, the focal length of the lens, and the sensing length of the diode array and the number of elements (N) contained in the array. The resolution of the system is approximately R/2N. We show for the system used here that this resolution is approximately 0.2%. In the configuration selected, elevation changes of 0.16 mm could be detected over a surface elevation range of 87 mm. The sampling rate of the system is 1000 Hz, which permits soil surfaces to be measured at speeds of up to 1 m s −1 with measurements taken at 1-mm spacing. Measurements of individual raindrop impacts on the soil and of soil surfaces before and after rain show the versatility of the laser surface profiler, which has applications in studies of erosion processes, surface storage and soil trafficability

  7. Dynamic Bubble Surface Tension Measurements in Northwest Atlantic Seawater

    Science.gov (United States)

    Kieber, D. J.; Long, M. S.; Keene, W. C.; Kinsey, J. D.; Frossard, A. A.; Beaupre, S. R.; Duplessis, P.; Maben, J. R.; Lu, X.; Chang, R.; Zhu, Y.; Bisgrove, J.

    2017-12-01

    Numerous reports suggest that most organic matter (OM) associated with newly formed primary marine aerosol (PMA) originates from the sea-surface microlayer. However, surface-active OM rapidly adsorbs onto bubble surfaces in the water column and is ejected into the atmosphere when bubbles burst at the air-water interface. Here we present dynamic surface tension measurements of bubbles produced in near surface seawater from biologically productive and oligotrophic sites and in deep seawater collected from 2500 m in the northwest Atlantic. In all cases, the surface tension of bubble surfaces decreased within seconds after the bubbles were exposed to seawater. These observations demonstrate that bubble surfaces are rapidly saturated by surfactant material scavenged from seawater. Spatial and diel variability in bubble surface evolution indicate corresponding variability in surfactant concentrations and/or composition. Our results reveal that surface-active OM is found throughout the water column, and that at least some surfactants are not of recent biological origin. Our results also support the hypothesis that the surface microlayer is a minor to negligible source of OM associated with freshly produced PMA.

  8. Measurement for Surface Tension of Aqueous Inorganic Salt

    Directory of Open Access Journals (Sweden)

    Jiming Wen

    2018-03-01

    Full Text Available Bubble columns are effective means of filtration in filtered containment venting systems. Here, the surface tension has a significant influence on bubble size distribution and bubble deformation, which have a strong impact on the behavior of the bubble column. The influence of aqueous inorganic compounds on the surface tension depends on the electrolytic activity, Debye length, entropy of ion hydration, and surface deficiencies or excess. In this work, the surface tensions of same specific aqueous solutions have been measured by different methods including platinum plate method, platinum ring method, and maximum bubble pressure method. The measured surface tensions of both sodium hydroxide and sodium thiosulfate are less than that of water. As solution temperature ranges from 20 to 75°C, the surface tension of 0.5 mol/L sodium hydroxide solution decreases from 71 to 55 mN/m while that of 1 mol/L solution decreases from 60 to 45 mN/m. Similarly during the same temperature range, the surface tension of 0.5 mol/L sodium thiosulfate decreases from 70 to 38 mN/m, and that of 1 mol/L sodium thiosulfate is between 68 and 36 mN/m. The analysis for the influence mechanism of aqueous inorganic on surface tension is provided. In addition, experimental results show that the surface tension of solid aerosol suspension liquid has no obvious difference from that of distilled water.

  9. Efficient and Adaptive Methods for Computing Accurate Potential Surfaces for Quantum Nuclear Effects: Applications to Hydrogen-Transfer Reactions.

    Science.gov (United States)

    DeGregorio, Nicole; Iyengar, Srinivasan S

    2018-01-09

    We present two sampling measures to gauge critical regions of potential energy surfaces. These sampling measures employ (a) the instantaneous quantum wavepacket density, an approximation to the (b) potential surface, its (c) gradients, and (d) a Shannon information theory based expression that estimates the local entropy associated with the quantum wavepacket. These four criteria together enable a directed sampling of potential surfaces that appears to correctly describe the local oscillation frequencies, or the local Nyquist frequency, of a potential surface. The sampling functions are then utilized to derive a tessellation scheme that discretizes the multidimensional space to enable efficient sampling of potential surfaces. The sampled potential surface is then combined with four different interpolation procedures, namely, (a) local Hermite curve interpolation, (b) low-pass filtered Lagrange interpolation, (c) the monomial symmetrization approximation (MSA) developed by Bowman and co-workers, and (d) a modified Shepard algorithm. The sampling procedure and the fitting schemes are used to compute (a) potential surfaces in highly anharmonic hydrogen-bonded systems and (b) study hydrogen-transfer reactions in biogenic volatile organic compounds (isoprene) where the transferring hydrogen atom is found to demonstrate critical quantum nuclear effects. In the case of isoprene, the algorithm discussed here is used to derive multidimensional potential surfaces along a hydrogen-transfer reaction path to gauge the effect of quantum-nuclear degrees of freedom on the hydrogen-transfer process. Based on the decreased computational effort, facilitated by the optimal sampling of the potential surfaces through the use of sampling functions discussed here, and the accuracy of the associated potential surfaces, we believe the method will find great utility in the study of quantum nuclear dynamics problems, of which application to hydrogen-transfer reactions and hydrogen

  10. Intermolecular potential energy surface and thermophysical properties of ethylene oxide.

    Science.gov (United States)

    Crusius, Johann-Philipp; Hellmann, Robert; Hassel, Egon; Bich, Eckard

    2014-10-28

    A six-dimensional potential energy hypersurface (PES) for two interacting rigid ethylene oxide (C2H4O) molecules was determined from high-level quantum-chemical ab initio calculations. The counterpoise-corrected supermolecular approach at the MP2 and CCSD(T) levels of theory was utilized to determine interaction energies for 10178 configurations of two molecules. An analytical site-site potential function with 19 sites per ethylene oxide molecule was fitted to the interaction energies and fine tuned to agree with data for the second acoustic virial coefficient from accurate speed of sound measurements. The PES was validated by computing the second virial coefficient, shear viscosity, and thermal conductivity. The values of these properties are substantiated by the best experimental data as they tend to fall within the uncertainty intervals and also obey the experimental temperature functions, except for viscosity, where experimental data are insufficient. Due to the lack of reliable data, especially for the transport properties, our calculated values are currently the most accurate estimates for these properties of ethylene oxide.

  11. Potential Energy Surface of NO on Pt(997: Adsorbed States and Surface Diffusion

    Directory of Open Access Journals (Sweden)

    N. Tsukahara

    2012-01-01

    Full Text Available The potential energy surface (PES of NO on Pt(997 has been elucidated: the adsorption states and diffusion processes of NO on Pt(997 at low coverage were investigated by using infrared reflection absorption spectroscopy (IRAS and scanning tunneling microscopy (STM. When NO molecules adsorb on a surface at a low temperature (11 K, each molecule transiently migrates on the surface from the first impact point to a possible adsorption site. We found that there are four stable adsorption sites for NO on Pt(997: a bridge site of the upper step, an fcc- (or hcp- hollow site of the terrace, an on-top site of the terrace, and an fcc-hollow site of the lower step. At higher temperatures above 45 K, NO molecules start to migrate thermally to more stable adsorption sites on a terrace, and they are finally trapped at the bridge sites of the step, which are the most stable among the four sites.

  12. RZP 202 - a modular system for surface density measurement

    International Nuclear Information System (INIS)

    Severa, L.; Merinsky, J.

    The sensing element is an ionization chamber of the type that has maximum sensitivity to beta radiation of the used radionuclide ( 147 Pm, 85 Kr, 90 Sr- 90 Y) or to gamma radiation of radionuclide 241 Am. Collimation shields were developed for the said sources. Measurement of the ionization currents is made with an electrometer with a vibration capacitor. Invariable configuration is secured by a measuring arm. The modular units are of the CAMAC system design. The surface density meters measure deviations from the rated surface density. The scale for inputting surface density is linear. The configuration, functional continuity of the individual parts and the possibility of variant designs of surface density meters are described and the technical parameters of RZP 202 and its configuration and design are given

  13. Space potential, temperature, and density profile measurements on RENTOR

    International Nuclear Information System (INIS)

    Schoch, P.M.

    1983-05-01

    Radial profiles of the space potential, electron temperature, and density have been measured on RENTOR with a heavy-ion-beam probe. The potential profile has been compared to predictions from a stochastic magnetic field fluctuation theory, using the measured temperature and density profiles. The comparison shows strong qualitative agreement in that the potential is positive and the order of T/sub e//e. There is some quantitative disagreement in that the measured radial electric fields are somewhat smaller than the theoretical predictions. To facilitate this comparison, a detailed analysis of the possible errors has been completed

  14. Advances in the Surface Renewal Flux Measurement Method

    Science.gov (United States)

    Shapland, T. M.; McElrone, A.; Paw U, K. T.; Snyder, R. L.

    2011-12-01

    The measurement of ecosystem-scale energy and mass fluxes between the planetary surface and the atmosphere is crucial for understanding geophysical processes. Surface renewal is a flux measurement technique based on analyzing the turbulent coherent structures that interact with the surface. It is a less expensive technique because it does not require fast-response velocity measurements, but only a fast-response scalar measurement. It is therefore also a useful tool for the study of the global cycling of trace gases. Currently, surface renewal requires calibration against another flux measurement technique, such as eddy covariance, to account for the linear bias of its measurements. We present two advances in the surface renewal theory and methodology that bring the technique closer to becoming a fully independent flux measurement method. The first advance develops the theory of turbulent coherent structure transport associated with the different scales of coherent structures. A novel method was developed for identifying the scalar change rate within structures at different scales. Our results suggest that for canopies less than one meter in height, the second smallest coherent structure scale dominates the energy and mass flux process. Using the method for resolving the scalar exchange rate of the second smallest coherent structure scale, calibration is unnecessary for surface renewal measurements over short canopies. This study forms the foundation for analysis over more complex surfaces. The second advance is a sensor frequency response correction for measuring the sensible heat flux via surface renewal. Inexpensive fine-wire thermocouples are frequently used to record high frequency temperature data in the surface renewal technique. The sensible heat flux is used in conjunction with net radiation and ground heat flux measurements to determine the latent heat flux as the energy balance residual. The robust thermocouples commonly used in field experiments

  15. Measuring sea surface height with a GNSS-Wave Glider

    Science.gov (United States)

    Morales Maqueda, Miguel Angel; Penna, Nigel T.; Foden, Peter R.; Martin, Ian; Cipollini, Paolo; Williams, Simon D.; Pugh, Jeff P.

    2017-04-01

    A GNSS-Wave Glider is a novel technique to measure sea surface height autonomously using the Global Navigation Satellite System (GNSS). It consists of an unmanned surface vehicle manufactured by Liquid Robotics, a Wave Glider, and a geodetic-grade GNSS antenna-receiver system, with the antenna installed on a mast on the vehicle's deck. The Wave Glider uses the differential wave motion through the water column for propulsion, thus guaranteeing an, in principle, indefinite autonomy. Solar energy is collected to power all on-board instrumentation, including the GNSS system. The GNSS-Wave Glider was first tested in Loch Ness in 2013, demonstrating that the technology is capable of mapping geoid heights within the loch with an accuracy of a few centimetres. The trial in Loch Ness did not conclusively confirm the reliability of the technique because, during the tests, the state of the water surface was much more benign than would normally be expect in the open ocean. We now report on a first deployment of a GNSS-Wave Glider in the North Sea. The deployment took place in August 2016 and lasted thirteen days, during which the vehicle covered a distance of about 350 nautical miles in the north western North Sea off Great Britain. During the experiment, the GNSS-Wave Glider experienced sea states between 1 (0-0.1 m wave heights) and 5 (2.5-4 m wave heights). The GNSS-Wave Glider data, recorded at 5 Hz frequency, were analysed using a post-processed kinematic GPS-GLONASS precise point positioning (PPP) approach, which were quality controlled using double difference GPS kinematic processing with respect to onshore reference stations. Filtered with a 900 s moving-average window, the PPP heights reveal geoid patterns in the survey area that are very similar to the EGM2008 geoid model, thus demonstrating the potential use of a GNSS-Wave Glider for marine geoid determination. The residual of subtracting the modelled or measured marine geoid from the PPP signal combines information

  16. Nanoscale surface potential imaging of the photocatalytic TiO2 films on aluminum

    DEFF Research Database (Denmark)

    Daviðsdóttir, Svava; Dirscherl, Kai; Canulescu, Stela

    2013-01-01

    in the surface potential of TiO2 coatings upon UV-illumination are closely correlated to the band gap and thickness of the coatings. The inhomogeneity surface potential distribution of a 100 nm TiO2 film indicates a heterogeneous coating. Transition to a homogeneous surface potential distribution was observed...

  17. Stern potential and Debye length measurements in dilute ionic solutions with electrostatic force microscopy

    International Nuclear Information System (INIS)

    Kumar, Bharat; Crittenden, Scott R

    2013-01-01

    We demonstrate the ability to measure Stern potential and Debye length in dilute ionic solution with atomic force microscopy. We develop an analytic expression for the second harmonic force component of the capacitive force in an ionic solution from the linearized Poisson–Boltzmann equation. This allows us to calibrate the AFM tip potential and, further, obtain the Stern potential of sample surfaces. In addition, the measured capacitive force is independent of van der Waals and double layer forces, thus providing a more accurate measure of Debye length. (paper)

  18. Stern potential and Debye length measurements in dilute ionic solutions with electrostatic force microscopy.

    Science.gov (United States)

    Kumar, Bharat; Crittenden, Scott R

    2013-11-01

    We demonstrate the ability to measure Stern potential and Debye length in dilute ionic solution with atomic force microscopy. We develop an analytic expression for the second harmonic force component of the capacitive force in an ionic solution from the linearized Poisson-Boltzmann equation. This allows us to calibrate the AFM tip potential and, further, obtain the Stern potential of sample surfaces. In addition, the measured capacitive force is independent of van der Waals and double layer forces, thus providing a more accurate measure of Debye length.

  19. Surface processing: existing and potential applications of ultraviolet light.

    Science.gov (United States)

    Manzocco, Lara; Nicoli, Maria Cristina

    2015-01-01

    Solid foods represent optimal matrices for ultraviolet processing with effects well beyond nonthermal surface disinfection. UV radiation favors hormetic response in plant tissues and degradation of toxic compound on the product surface. Photoinduced reactions can also provide unexplored possibilities to steer structure and functionality of food biopolymers. The possibility to extensively exploit this technology will depend on availability of robust information about efficacious processing conditions and adequate strategies to completely and homogeneously process food surface.

  20. Outdoor surface temperature measurement: ground truth or lie?

    Science.gov (United States)

    Skauli, Torbjorn

    2004-08-01

    Contact surface temperature measurement in the field is essential in trials of thermal imaging systems and camouflage, as well as for scene modeling studies. The accuracy of such measurements is challenged by environmental factors such as sun and wind, which induce temperature gradients around a surface sensor and lead to incorrect temperature readings. In this work, a simple method is used to test temperature sensors under conditions representative of a surface whose temperature is determined by heat exchange with the environment. The tested sensors are different types of thermocouples and platinum thermistors typically used in field trials, as well as digital temperature sensors. The results illustrate that the actual measurement errors can be much larger than the specified accuracy of the sensors. The measurement error typically scales with the difference between surface temperature and ambient air temperature. Unless proper care is taken, systematic errors can easily reach 10% of this temperature difference, which is often unacceptable. Reasonably accurate readings are obtained using a miniature platinum thermistor. Thermocouples can perform well on bare metal surfaces if the connection to the surface is highly conductive. It is pointed out that digital temperature sensors have many advantages for field trials use.

  1. Measuring and modeling surface sorption dynamics of organophosphate flame retardants on impervious surfaces

    Data.gov (United States)

    U.S. Environmental Protection Agency — The data presented in this data file is a product of a journal publication. The dataset contains measured and model predicted OPFRs gas-phase and surface-phase...

  2. Measurement of nuclear potentials from fusion excitation functions

    International Nuclear Information System (INIS)

    Huizenga, J.R.; Birkelund, J.R.

    1984-01-01

    The basis for measuring nuclear potentials from fusion excitation functions at energies above barrier is reviewed. It is argued that because of experimental and conceptual problems fusion excitation functions at high energies cannot lead to model independent measurements of internuclear potential at small separations. The Al 27 + Ne 20 reaction previously analyzed by others is used as an example of problems arising from the inability to distinguish complete and incomplete fusion in experimental data

  3. Noise evaluation of a point autofocus surface topography measuring instrument

    Science.gov (United States)

    Maculotti, Giacomo; Feng, Xiaobing; Galetto, Maurizio; Leach, Richard

    2018-06-01

    In this work, the measurement noise of a point autofocus surface topography measuring instrument is evaluated, as the first step towards establishing a route to traceability for this type of instrument. The evaluation is based on the determination of the metrological characteristics for noise as outlined in draft ISO specification standards by using a calibrated optical flat. The static noise and repeatability of the autofocus sensor are evaluated. The influence of environmental disturbances on the measured surface topography and the built-in software to compensate for such influences are also investigated. The instrument was found to have a measurement noise of approximately 2 nm or, when expressed with the measurement bandwidth, 0.4 nm for a single-point measurement.

  4. Practical aspects of tritium measurement in ground and surface waters

    Energy Technology Data Exchange (ETDEWEB)

    Nitzsche, O [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Angewandte Physik; Hebert, D [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Angewandte Physik

    1997-03-01

    Tritium measurements are a powerful tool in hydrological and hydrogeological investigations for detecting mean residence times of several water reservoirs. Due to the low tritium activities in precipitation, ground and surface waters a low level measurement is necessary. Therefore often the liquid scintillation counting after an electrolytic enrichment of water is used. In this paper some practical aspects and problems of measurement are discussed and the problem of contamination in low level laboratories is shown. (orig.)

  5. Surface Moisture Measurement System Operation and Maintenance Manual

    International Nuclear Information System (INIS)

    Ritter, G.A.; Pearce, K.L.; Stokes, T.L.

    1995-12-01

    This operations and maintenance manual addresses deployment, equipment and field hazards, operating instructions, calibration verification, removal, maintenance, and other pertinent information necessary to safely operate and store the Surface Moisture Measurement System (SMMS) and Liquid Observation Well Moisture Measurement System (LOWMMS). These systems were developed primarily in support of Tank Waste Remediation System (TWRS) Safety Programs for moisture measurement in organic and ferrocyanide watch list tanks

  6. Surface Forces Apparatus measurements of interactions between rough and reactive calcite surfaces.

    Science.gov (United States)

    Dziadkowiec, Joanna; Javadi, Shaghayegh; Bratvold, Jon Einar; Nilsen, Ola; Røyne, Anja

    2018-05-28

    Nm-range forces acting between calcite surfaces in water affect macroscopic properties of carbonate rocks and calcite-based granular materials, and are significantly influenced by calcite surface recrystallization. We suggest that the repulsive mechanical effects related to nm-scale surface recrystallization of calcite in water could be partially responsible for the observed decrease of cohesion in calcitic rocks saturated with water. Using the Surface Forces Apparatus (SFA), we simultaneously followed the calcite reactivity and measured the forces in water in two surface configurations: between two rough calcite surfaces (CC), or between rough calcite and a smooth mica surface (CM). We used nm-scale rough, polycrystalline calcite films prepared by Atomic Layer Deposition (ALD). We measured only repulsive forces in CC in CaCO 3 -saturated water, which was related to roughness and possibly to repulsive hydration effects. Adhesive or repulsive forces were measured in CM in CaCO 3 -saturated water depending on calcite roughness, and the adhesion was likely enhanced by electrostatic effects. The pull-off adhesive force in CM became stronger with time and this increase was correlated with a decrease of roughness at contacts, which parameter could be estimated from the measured force-distance curves. That suggested a progressive increase of real contact areas between the surfaces, caused by gradual pressure-driven deformation of calcite surface asperities during repeated loading-unloading cycles. Reactivity of calcite was affected by mass transport across nm to µm-thick gaps between the surfaces. Major roughening was observed only for the smoothest calcite films, where gaps between two opposing surfaces were nm-thick over µm-sized areas, and led to force of crystallization that could overcome confining pressures of the order of MPa. Any substantial roughening of calcite caused a significant increase of the repulsive mechanical force contribution.

  7. Four-point probe measurements using current probes with voltage feedback to measure electric potentials

    Science.gov (United States)

    Lüpke, Felix; Cuma, David; Korte, Stefan; Cherepanov, Vasily; Voigtländer, Bert

    2018-02-01

    We present a four-point probe resistance measurement technique which uses four equivalent current measuring units, resulting in minimal hardware requirements and corresponding sources of noise. Local sample potentials are measured by a software feedback loop which adjusts the corresponding tip voltage such that no current flows to the sample. The resulting tip voltage is then equivalent to the sample potential at the tip position. We implement this measurement method into a multi-tip scanning tunneling microscope setup such that potentials can also be measured in tunneling contact, allowing in principle truly non-invasive four-probe measurements. The resulting measurement capabilities are demonstrated for \

  8. A Comparison of Streaming and Microelectrophoresis Methods for Obtaining the zeta Potential of Granular Porous Media Surfaces.

    Science.gov (United States)

    Johnson

    1999-01-01

    The electrokinetic behavior of granular quartz sand in aqueous solution is investigated by both microelectrophoresis and streaming potential methods. zeta potentials of surfaces composed of granular quartz obtained via streaming potential methods are compared to electrophoretic mobility zeta potential values of colloid-sized quartz fragments. The zeta values generated by these alternate methods are in close agreement over a wide pH range and electrolyte concentrations spanning several orders of magnitude. Streaming measurements performed on chemically heterogeneous mixtures of physically homogeneous sand are shown to obey a simple mixing model based on the surface area-weighted average of the streaming potentials associated with the individual end members. These experimental results support the applicability of the streaming potential method as a means of determining the zeta potential of granular porous media surfaces. Copyright 1999 Academic Press.

  9. Surface grafted polymer brushes: potential applications in dengue biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Baratela, Fernando Jose Costa; Higa, Olga Zazuco, E-mail: ozahiga@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Faria, Henrique Antonio Mendonca de; Queiroz, Alvaro Antonio Alencar de, E-mail: alencar@unifei.edu.br [Universidade Federal de Itajuba (UNIFEI), Itajuba, MG (Brazil). Instituto de Fisica e Quimica

    2013-07-01

    A polymer brush membrane-based ultrasensitive biosensor for dengue diagnosis was constructed using poly(hydroxyethyl methacrylate) (PHEMA) brushes immobilized onto low density polyethylene (LDPE) films. LDPE surface films were initially modified by Ar{sup +} ion irradiation to activate the polymer surface. Subsequently, graft polymerization of 2-hydroxyethyl methacrylate onto the activated LDPE surface was carried out under aqueous conditions to create patterned polymer brushes of PHEMA. The grafted PHEMA brushes were characterized by Fourier transform-infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and contact angle analysis. The SEM observations showed that selective surface activation with Ar+ implantation and graft polymerization on the selectively activated surface had occurred. The PHEMA brushes were electrically characterized in the presence of concentrations of human immunoglobulin (IgG). The proposed amperometric biosensor was successfully used for determination of IgG in physiologic samples with excellent responses. (author)

  10. Surface grafted polymer brushes: potential applications in dengue biosensors

    International Nuclear Information System (INIS)

    Baratela, Fernando Jose Costa; Higa, Olga Zazuco; Faria, Henrique Antonio Mendonca de; Queiroz, Alvaro Antonio Alencar de

    2013-01-01

    A polymer brush membrane-based ultrasensitive biosensor for dengue diagnosis was constructed using poly(hydroxyethyl methacrylate) (PHEMA) brushes immobilized onto low density polyethylene (LDPE) films. LDPE surface films were initially modified by Ar + ion irradiation to activate the polymer surface. Subsequently, graft polymerization of 2-hydroxyethyl methacrylate onto the activated LDPE surface was carried out under aqueous conditions to create patterned polymer brushes of PHEMA. The grafted PHEMA brushes were characterized by Fourier transform-infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and contact angle analysis. The SEM observations showed that selective surface activation with Ar+ implantation and graft polymerization on the selectively activated surface had occurred. The PHEMA brushes were electrically characterized in the presence of concentrations of human immunoglobulin (IgG). The proposed amperometric biosensor was successfully used for determination of IgG in physiologic samples with excellent responses. (author)

  11. Inverse analysis of inner surface temperature history from outer surface temperature measurement of a pipe

    International Nuclear Information System (INIS)

    Kubo, S; Ioka, S; Onchi, S; Matsumoto, Y

    2010-01-01

    When slug flow runs through a pipe, nonuniform and time-varying thermal stresses develop and there is a possibility that thermal fatigue occurs. Therefore it is necessary to know the temperature distributions and the stress distributions in the pipe for the integrity assessment of the pipe. It is, however, difficult to measure the inner surface temperature directly. Therefore establishment of the estimation method of the temperature history on inner surface of pipe is needed. As a basic study on the estimation method of the temperature history on the inner surface of a pipe with slug flow, this paper presents an estimation method of the temperature on the inner surface of a plate from the temperature on the outer surface. The relationship between the temperature history on the outer surface and the inner surface is obtained analytically. Using the results of the mathematical analysis, the inverse analysis method of the inner surface temperature history estimation from the outer surface temperature history is proposed. It is found that the inner surface temperature history can be estimated from the outer surface temperature history by applying the inverse analysis method, even when it is expressed by the multiple frequency components.

  12. Measuring Polanyi Potentials for Chemsorb 1000 and Chemsorb 3800

    Science.gov (United States)

    Monje, Oscar; Surma, Jan M.; Kayatin, Matthew J.; Perry, Jay L.

    2016-01-01

    Polanyi adsorption potential plots are used to predict the adsorptive capacities of volatile organic compounds onto activated carbons. The design and construction of a test rig for measuring equilibrium adsorption capacities suitable for constructing Polanyi adsorption potential plots for candidate sorbents suitable for use in ECLS systems is presented. The adsorptive capacities of Chemsorb(TradeMark) 1000 and Chemsorb(TradeMark) 800 for ethanol and acetone were measured. The capacities and Polanyi adsorption potential plots for these commercially-available sorbents were compared to that of Barnebey Sutcliffe Type 3032, an acid-impregnated activated carbon utilized aboard the International Space Station.

  13. An instrument for the measurement of road surface reflection properties

    DEFF Research Database (Denmark)

    Corell, Dennis Dan; Sørensen, K.

    2017-01-01

    surfaces in use have changed - for instance to road surface types with less noise from wheel passages. Because of this, a co-operation between the road administrations of the Nordic countries (abbreviated NMF) decided to construct a portable instrument to be used on selections of traffic roads within......Road surface reflection data in the form of standard r-tables serve as input for design calculations of road lighting installations on traffic roads. However, in several countries the use of the standard r-tables has not been verified by measurement in a long period of time, while the types of road...

  14. Accuracy and reliability of three-dimensional surface reconstruction measurement

    International Nuclear Information System (INIS)

    Mizukami, Chikashi; Yamamoto, Etsuo; Ohmura, Masaki; Oiki, Hiroyuki; Tsuji, Jun; Muneta, Yuki; Tanabe, Makito; Hakuba, Nobuhiro; Azemoto, Syougo.

    1993-01-01

    We are using a new three-dimensional (3-D) surface reconstruction system to measure the temporal bones. This system offers the advantage of observation of the external aperture of the vestibular aqueduct and the porus acusticus internus in living subjects. However, its accuracy has not been confirmed. To investigate the accuracy of this new system, we measured the length of an in situ ceramic ossicular replacement prosthesis (CORP) of known length of 6.0 mm using 3-D surface reconstruction, conventional plain X-ray and polytomography. The CORP was scanned in the axial, sagittal and oblique directions. The mean measured length obtained with the 3-D surface reconstruction images was 5.94±0.21 on vertical scans, 5.91±0.27 on horizontal scans, and 6.01±0.25 on oblique scans. There were no significant differences among the measured lengths obtained in the three directions. Therefore, this 3-D surface reconstruction measurement system is considered to be reliable. Conversely, the mean measured length obtained by plain X-ray was 7.98±0.20, and by polytomography it was 7.94±0.23. These conventional methods have the inherent disadvantage of magnification of size which consequently requires correction. (author)

  15. Field measurement of albedo for limited extent test surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Sailor, David J. [Portland State University, Department of Mechanical and Materials Engineering, P.O. Box 751-ME, Portland, OR 97207 (United States); Resh, Kyle; Segura, Del [Tulane University, Department of Mechanical Engineering, 400 Lindy Boggs Center, New Orleans, LA 70118 (United States)

    2006-05-15

    A new method is introduced for field measurement of surface albedo. This method consists of the use of a cylindrical shade ring made of opaque fabric with a known (low) albedo placed over a test surface. The albedo measurement is accomplished using two small pyranometers situated so that the downward-facing pyranometer receives radiation only from the test surface and the shade ring. The upward-facing pyranometer simultaneously records the incoming solar radiation. The radiation received by the downward-facing pyramometer is a combination of reflected radiation from shaded and unshaded portions of these two surfaces, requiring detailed accounting of the resulting view factor geometries. The method presented here improves upon past approaches by allowing for smaller sample sizes, minimizing errors associated with reflective properties of the surroundings, and allowing for accurate measurements even under partially cloudy skies. In addition to these methodological improvements we introduce an approach for estimating the uncertainty in the resulting albedo measurements. Results from field measurements are presented to validate the measurement protocol, and to compare its accuracy with the accuracy of a published standard. (author)

  16. Can foot anthropometric measurements predict dynamic plantar surface contact area?

    Directory of Open Access Journals (Sweden)

    Collins Natalie

    2009-10-01

    Full Text Available Abstract Background Previous studies have suggested that increased plantar surface area, associated with pes planus, is a risk factor for the development of lower extremity overuse injuries. The intent of this study was to determine if a single or combination of foot anthropometric measures could be used to predict plantar surface area. Methods Six foot measurements were collected on 155 subjects (97 females, 58 males, mean age 24.5 ± 3.5 years. The measurements as well as one ratio were entered into a stepwise regression analysis to determine the optimal set of measurements associated with total plantar contact area either including or excluding the toe region. The predicted values were used to calculate plantar surface area and were compared to the actual values obtained dynamically using a pressure sensor platform. Results A three variable model was found to describe the relationship between the foot measures/ratio and total plantar contact area (R2 = 0.77, p R2 = 0.76, p Conclusion The results of this study indicate that the clinician can use a combination of simple, reliable, and time efficient foot anthropometric measurements to explain over 75% of the plantar surface contact area, either including or excluding the toe region.

  17. Measurement of water potential in low-level waste management

    International Nuclear Information System (INIS)

    Jones, T.L.; Gee, G.W.; Kirkham, R.R.; Gibson, D.D.

    1982-08-01

    The measurement of soil water is important to the shallow land burial of low-level waste. Soil water flow is the principle mechanism of radionuclide transport, allows the establishment of stabilizing vegetation and also governs the dissolution and release rates of the waste. This report focuses on the measurement of soil water potential and provides an evaluation of several field instruments that are available for use to monitor waste burial sites located in arid region soils. The theoretical concept of water potential is introduced and its relationship to water content and soil water flow is discussed. Next, four major areas of soils research are presented in terms of their dependence on the water potential concept. There are four basic types of sensors used to measure soil water potential. These are: (1) tensiometers; (2) soil psychrometers; (3) electrical resistance blocks; and (4) heat dissipation probes. Tensiometers are designed to measure the soil water potential directly by measuring the soil water pressure. Monitoring efforts at burial sites require measurements of soil water over long time periods. They also require measurements at key locations such as waste-soil interfaces and within any barrier system installed. Electrical resistance blocks are well suited for these types of measurements. The measurement of soil water potential can be a difficult task. There are several sensors commercially available; however, each has its own limitations. It is important to carefully select the appropriate sensor for the job. The accuracy, range, calibration, and stability of the sensor must be carefully considered. This study suggests that for waste management activities, the choice of sensor will be the tensiometer for precise soil characterization studies and the electrical resistance block for long term monitoring programs

  18. Metrological Aspects of Surface Topographies Produced by Different Machining Operations Regarding Their Potential Functionality

    Directory of Open Access Journals (Sweden)

    Żak Krzysztof

    2017-06-01

    Full Text Available This paper presents a comprehensive methodology for measuring and characterizing the surface topographies on machined steel parts produced by precision machining operations. The performed case studies concern a wide spectrum of topographic features of surfaces with different geometrical structures but the same values of the arithmetic mean height Sa. The tested machining operations included hard turning operations performed with CBN tools, grinding operations with Al2O3 ceramic and CBN wheels and superfinish using ceramic stones. As a result, several characteristic surface textures with the Sa roughness parameter value of about 0.2 μm were thoroughly characterized and compared regarding their potential functional capabilities. Apart from the standard 2D and 3D roughness parameters, the fractal, motif and frequency parameters were taken in the consideration.

  19. Characteristic features of net information measures for constrained Coulomb potentials

    International Nuclear Information System (INIS)

    Patil, S H; Sen, K D; Watson, N A; Jr, H E Montgomery

    2007-01-01

    The dimensional analyses of the position and momentum variance based quantum mechanical Heisenberg uncertainty measure and the other useful net entropic information measures for the bound states of two constrained Coulomb potentials are reported for the first time. The potentials describe an electron moving in the central field due to a nucleus of charge Z with radius R defining the constraints as (a) the truncated potential given by -Z/(r n +R n ) 1/n , and (b) the radius of the impenetrable spherical wall. The net information measures for the two potentials are explicitly shown to be independent of the scaling of the set [Z, R] at a fixed value of ZR. Analytic proof is presented, for the first time, showing the presence of a characteristic extremum in the variation of the net information entropy as a function of the radius R with its location scaling as Z -1 . Numerical results are presented which support the validity of the scaling properties

  20. Surface potential on gold nanodisc arrays fabricated on silicon under light irradiation

    Science.gov (United States)

    Ezaki, Tomotarou; Matsutani, Akihiro; Nishioka, Kunio; Shoji, Dai; Sato, Mina; Okamoto, Takayuki; Isobe, Toshihiro; Nakajima, Akira; Matsushita, Sachiko

    2018-06-01

    This paper proposes Kelvin probe force microscopy (KFM) as a new measurement method of plasmon phenomenon. The surface potential of two arrays, namely, a monomeric array and a tetrameric array, of gold nanodiscs (600 nm diameter) on a silicon substrate fabricated by electron beam lithography was investigated by KFM with the view point of irradiation light wavelength change. In terms of the value of the surface potential, contrasting behaviour, a negative shift in the monomeric disc array and a positive shift in the tetrameric disc array, was observed by light irradiation. This interesting behaviour is thought to be related to a difference in localised plasmons caused by the disc arrangement and was investigated from various viewpoints, including Rayleigh anomalies. Finally, this paper reveals that KFM is powerful not only to investigate the plasmonic behaviour but also to predict the electron transportation.

  1. Reaction Mechanisms on Multiwell Potential Energy Surfaces in Combustion (and Atmospheric) Chemistry

    International Nuclear Information System (INIS)

    Osborn, David L.

    2017-01-01

    Chemical reactions occurring on a potential energy surface with multiple wells are ubiquitous in low temperature combustion and the oxidation of volatile organic compounds in earth’s atmosphere. The rich variety of structural isomerizations that compete with collisional stabilization make characterizing such complex-forming reactions challenging. This review describes recent experimental and theoretical advances that deliver increasingly complete views of their reaction mechanisms. New methods for creating reactive intermediates coupled with multiplexed measurements provide many experimental observables simultaneously. Automated methods to explore potential energy surfaces can uncover hidden reactive pathways, while master equation methods enable a holistic treatment of both sequential and well-skipping pathways. Our ability to probe and understand nonequilibrium effects and reaction sequences is increasing. These advances provide the fundamental science base for predictive models of combustion and the atmosphere that are crucial to address global challenges.

  2. Reaction Mechanisms on Multiwell Potential Energy Surfaces in Combustion (and Atmospheric) Chemistry

    Science.gov (United States)

    Osborn, David L.

    2017-05-01

    Chemical reactions occurring on a potential energy surface with multiple wells are ubiquitous in low-temperature combustion and in the oxidation of volatile organic compounds in Earth's atmosphere. The rich variety of structural isomerizations that compete with collisional stabilization makes characterizing such complex-forming reactions challenging. This review describes recent experimental and theoretical advances that deliver increasingly complete views of their reaction mechanisms. New methods for creating reactive intermediates coupled with multiplexed measurements provide many experimental observables simultaneously. Automated methods to explore potential energy surfaces can uncover hidden reactive pathways, and master equation methods enable a holistic treatment of both sequential and well-skipping pathways. Our ability to probe and understand nonequilibrium effects and reaction sequences is increasing. These advances provide the fundamental science base for predictive models of combustion and the atmosphere that are crucial to address global challenges.

  3. Surface temperature measurement of plasma facing components in tokamaks

    International Nuclear Information System (INIS)

    Amiel, Stephane

    2014-01-01

    During this PhD, the challenges on the non-intrusive surface temperature measurements of metallic plasma facing components in tokamaks are reported. Indeed, a precise material emissivity value is needed for classical infrared methods and the environment contribution has to be known particularly for low emissivities materials. Although methods have been developed to overcome these issues, they have been implemented solely for dedicated experiments. In any case, none of these methods are suitable for surface temperature measurement in tokamaks.The active pyrometry introduced in this study allows surface temperature measurements independently of reflected flux and emissivities using pulsed and modulated photothermal effect. This method has been validated in laboratory on metallic materials with reflected fluxes for pulsed and modulated modes. This experimental validation is coupled with a surface temperature variation induced by photothermal effect and temporal signal evolvement modelling in order to optimize both the heating source characteristics and the data acquisition and treatment. The experimental results have been used to determine the application range in temperature and detection wavelengths. In this context, the design of an active pyrometry system on tokamak has been completed, based on a bicolor camera for a thermography application in metallic (or low emissivity) environment.The active pyrometry method introduced in this study is a complementary technique of classical infrared methods used for thermography in tokamak environment which allows performing local and 2D surface temperature measurements independently of reflected fluxes and emissivities. (author) [fr

  4. Optimized Estimation of Surface Layer Characteristics from Profiling Measurements

    Directory of Open Access Journals (Sweden)

    Doreene Kang

    2016-01-01

    Full Text Available New sampling techniques such as tethered-balloon-based measurements or small unmanned aerial vehicles are capable of providing multiple profiles of the Marine Atmospheric Surface Layer (MASL in a short time period. It is desirable to obtain surface fluxes from these measurements, especially when direct flux measurements are difficult to obtain. The profiling data is different from the traditional mean profiles obtained at two or more fixed levels in the surface layer from which surface fluxes of momentum, sensible heat, and latent heat are derived based on Monin-Obukhov Similarity Theory (MOST. This research develops an improved method to derive surface fluxes and the corresponding MASL mean profiles of wind, temperature, and humidity with a least-squares optimization method using the profiling measurements. This approach allows the use of all available independent data. We use a weighted cost function based on the framework of MOST with the cost being optimized using a quasi-Newton method. This approach was applied to seven sets of data collected from the Monterey Bay. The derived fluxes and mean profiles show reasonable results. An empirical bias analysis is conducted using 1000 synthetic datasets to evaluate the robustness of the method.

  5. Potential barrier classification by short-time measurement

    International Nuclear Information System (INIS)

    Granot, Er'el; Marchewka, Avi

    2006-01-01

    We investigate the short-time dynamics of a delta-function potential barrier on an initially confined wave packet. There are mainly two conclusions: (A) At short times the probability density of the first particles that passed through the barrier is unaffected by it. (B) When the barrier is absorptive (i.e., its potential is imaginary) it affects the transmitted wave function at shorter times than a real potential barrier. Therefore, it is possible to distinguish between an imaginary and a real potential barrier by measuring its effect at short times only on the transmitting wave function

  6. Potential barrier classification by short-time measurement

    Science.gov (United States)

    Granot, Er'El; Marchewka, Avi

    2006-03-01

    We investigate the short-time dynamics of a delta-function potential barrier on an initially confined wave packet. There are mainly two conclusions: (A) At short times the probability density of the first particles that passed through the barrier is unaffected by it. (B) When the barrier is absorptive (i.e., its potential is imaginary) it affects the transmitted wave function at shorter times than a real potential barrier. Therefore, it is possible to distinguish between an imaginary and a real potential barrier by measuring its effect at short times only on the transmitting wave function.

  7. Gallium surface diffusion on GaAs (001) surfaces measured by crystallization dynamics of Ga droplets

    International Nuclear Information System (INIS)

    Bietti, Sergio; Somaschini, Claudio; Esposito, Luca; Sanguinetti, Stefano; Fedorov, Alexey

    2014-01-01

    We present accurate measurements of Ga cation surface diffusion on GaAs surfaces. The measurement method relies on atomic force microscopy measurement of the morphology of nano–disks that evolve, under group V supply, from nanoscale group III droplets, earlier deposited on the substrate surface. The dependence of the radius of such nano-droplets on crystallization conditions gives direct access to Ga diffusion length. We found an activation energy for Ga on GaAs(001) diffusion E A =1.31±0.15 eV, a diffusivity prefactor of D 0  = 0.53(×2.1±1) cm 2 s −1 that we compare with the values present in literature. The obtained results permit to better understand the fundamental physics governing the motion of group III ad–atoms on III–V crystal surfaces and the fabrication of designable nanostructures.

  8. Direct measurement of Cu surface self-diffusion on a checked surface

    International Nuclear Information System (INIS)

    Cousty, Jacques; Peix, Roger; Perraillon, Bernard.

    1976-01-01

    A radiotracer technique ( 64 Cu) was developed to measure surface diffusion on copper surfaces of total impurity concentration not exceeding some 10 -3 monolayers. The apparatus used consists of a slow electron diffraction device, an Auger analysis spectrometer (CMA), an ion gun and an evaporation device assembled in an ultra-vacuum chamber holding a residual pressure below 10 -10 Torr. A sample handler enables the surface studied to be positioned in front of each of these instruments. During the diffusion treatment the chemical composition of the surface is checked intermittently, and afterwards the spread of the deposit is measured outside the ultravacuum chamber. Slices several microns thick are removed and dissolved separately in dishes containing HNO 3 . The activity is then measured with a flow counter [fr

  9. Measurement of surface recombination velocity on heavily doped indium phosphide

    International Nuclear Information System (INIS)

    Jenkins, P.; Ghalla-Goradia, M.; Faur, M.; Bailey, S.

    1990-01-01

    The controversy surrounding the published low values of surface recombination velocity (SRV) in n-InP, solidified in recent years when modeling of existing n/p InP solar cells revealed that the front surface SRV had to be higher than 1 x 10 6 cm/sec in order to justify the poor blue response that is characteristic of all n/p InP solar cells. In this paper, SRV on heavily doped (>10 18 cm -3 )n-type and p-type InP is measured as a function of surface treatment. For the limited range of substrates and surface treatments studied, SRV and surface stability depend strongly on the surface treatment. SRVs of ∼10 5 cm/sec in both p-type and n-type InP are obtainable, but in n-type the low SRV surfaces were unstable, and the only stable surfaces on n-type had SRVs of >10 6 cm/sec

  10. Fermi surface measurements in actinide metals and compounds

    International Nuclear Information System (INIS)

    Arko, A.J.; Schirber, J.E.

    1978-01-01

    The various techniques of measuring Fermi Surface parameters are briefly discussed in terms f application to actinide systems. Particular emphasis is given the dHvA effect. Some general results found in the dHvA studies of actinide compounds are given. The dHvA effect has been measured in α-U and is presented in detail. None of the observed frequencies corresponds to closed surfaces. Results are compared to the calculations of Freeman, Koelling and Watson-Yang where qualitative agreement is observed

  11. LUNAR SURFACE AND DUST GRAIN POTENTIALS DURING THE EARTH’S MAGNETOSPHERE CROSSING

    Energy Technology Data Exchange (ETDEWEB)

    Vaverka, J.; Richterová, I.; Pavlu, J.; Šafránková, J.; Němeček, Z., E-mail: jana.safrankova@mff.cuni.cz [Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University in Prague, V Holešovičkách 2, 180 00 Prague (Czech Republic)

    2016-07-10

    Interaction between the lunar surface and the solar UV radiation and surrounding plasma environment leads to its charging by different processes like photoemission, collection of charged particles, or secondary electron emission (SEE). Whereas the photoemission depends only on the angle between the surface and direction to the Sun and varies only slowly, plasma parameters can change rapidly as the Moon orbits around the Earth. This paper presents numerical simulations of one Moon pass through the magnetospheric tail including the real plasma parameters measured by THEMIS as an input. The calculations are concentrated on different charges of the lunar surface itself and a dust grain lifted above this surface. Our estimations show that (1) the SEE leads to a positive charging of parts of the lunar surface even in the magnetosphere, where a high negative potential is expected; (2) the SEE is generally more important for isolated dust grains than for the lunar surface covered by these grains; and (3) the time constant of charging of dust grains depends on their diameter being of the order of hours for sub-micrometer grains. In view of these results, we discuss the conditions under which and the areas where a levitation of the lifted dust grains could be observed.

  12. Cold atoms near surfaces: designing potentials by sculpturing wires

    International Nuclear Information System (INIS)

    Della Pietra, Leonardo; Aigner, Simon; Hagen, Christoph vom; Lezec, Henri J; Schmiedmayer, Joerg

    2005-01-01

    The magnetic trapping potentials for atoms on atom chips are determined by the current flow pattern in the chip wires. By modifying the wire shape using focused ion beam nano-machining we can design specialized current flow patterns and therefore micro-design the magnetic trapping potentials. We give designs for a barrier, a quantum dot, and a double well or double barrier and show preliminary experiments with ultra cold atoms in these designed potentials

  13. Topography measurements for determining the decay factors in surface replication

    International Nuclear Information System (INIS)

    Song, J; Zheng, A; Vorburger, T V; Rubert, P

    2008-01-01

    The electro-forming technique is used at National Institute of Standards and Technology (NIST) for the production of standard reference material (SRM) 2461 standard casings to support nationwide ballistics measurement traceability and measurement quality control in the US. In order to ensure that the SRM casings are produced with virtually the same surface topography, it is necessary to test the decay factors of the replication process. Twenty-six replica casings are replicated from the same master casing for the decay factor tests. The NIST topography measurement system is used for measurements and correlations of surface topography. The topography decays are quantified by the cross-correlation function maximum CCF max . Based on the test, it is expected that 256 SRM casings can be replicated from the same master with CCF max values higher than 95%

  14. Measuring the Surface Temperature of the Cryosphere using Remote Sensing

    Science.gov (United States)

    Hall, Dorothy K.

    2012-01-01

    A general description of the remote sensing of cryosphere surface temperatures from satellites will be provided. This will give historical information on surface-temperature measurements from space. There will also be a detailed description of measuring the surface temperature of the Greenland Ice Sheet using Moderate-Resolution Imaging Spectroradiometer (MODIS) data which will be the focus of the presentation. Enhanced melting of the Greenland Ice Sheet has been documented in recent literature along with surface-temperature increases measured using infrared satellite data since 1981. Using a recently-developed climate data record, trends in the clear-sky ice-surface temperature (IST) of the Greenland Ice Sheet have been studied using the MODIS IST product. Daily and monthly MODIS ISTs of the Greenland Ice Sheet beginning on 1 March 2000 and continuing through 31 December 2010 are now freely available to download at 6.25-km spatial resolution on a polar stereographic grid. Maps showing the maximum extent of melt for the entire ice sheet and for the six major drainage basins have been developed from the MODIS IST dataset. Twelve-year trends of the duration of the melt season on the ice sheet vary in different drainage basins with some basins melting progressively earlier over the course of the study period. Some (but not all) of the basins also show a progressively-longer duration of melt. The consistency of this IST record, with temperature and melt records from other sources will be discussed.

  15. Electric field vector measurements in a surface ionization wave discharge

    International Nuclear Information System (INIS)

    Goldberg, Benjamin M; Adamovich, Igor V; Lempert, Walter R; Böhm, Patrick S; Czarnetzki, Uwe

    2015-01-01

    This work presents the results of time-resolved electric field vector measurements in a short pulse duration (60 ns full width at half maximum), surface ionization wave discharge in hydrogen using a picosecond four-wave mixing technique. Electric field vector components are measured separately, using pump and Stokes beams linearly polarized in the horizontal and vertical planes, and a polarizer placed in front of the infrared detector. The time-resolved electric field vector is measured at three different locations across the discharge gap, and for three different heights above the alumina ceramic dielectric surface, ∼100, 600, and 1100 μm (total of nine different locations). The results show that after breakdown, the discharge develops as an ionization wave propagating along the dielectric surface at an average speed of 1 mm ns −1 . The surface ionization wave forms near the high voltage electrode, close to the dielectric surface (∼100 μm). The wave front is characterized by significant overshoot of both vertical and horizontal electric field vector components. Behind the wave front, the vertical field component is rapidly reduced. As the wave propagates along the dielectric surface, it also extends further away from the dielectric surface, up to ∼1 mm near the grounded electrode. The horizontal field component behind the wave front remains quite significant, to sustain the electron current toward the high voltage electrode. After the wave reaches the grounded electrode, the horizontal field component experiences a secondary rise in the quasi-dc discharge, where it sustains the current along the near-surface plasma sheet. The measurement results indicate presence of a cathode layer formed near the grounded electrode with significant cathode voltage fall, ≈3 kV, due to high current density in the discharge. The peak reduced electric field in the surface ionization wave is 85–95 Td, consistent with dc breakdown field estimated from the Paschen

  16. Diffuse Reflectance Spectroscopy for Surface Measurement of Liver Pathology.

    Science.gov (United States)

    Nilsson, Jan H; Reistad, Nina; Brange, Hannes; Öberg, Carl-Fredrik; Sturesson, Christian

    2017-01-01

    Liver parenchymal injuries such as steatosis, steatohepatitis, fibrosis, and sinusoidal obstruction syndrome can lead to increased morbidity and liver failure after liver resection. Diffuse reflectance spectroscopy (DRS) is an optical measuring method that is fast, convenient, and established. DRS has previously been used on the liver with an invasive technique consisting of a needle that is inserted into the parenchyma. We developed a DRS system with a hand-held probe that is applied to the liver surface. In this study, we investigated the impact of the liver capsule on DRS measurements and whether liver surface measurements are representative of the whole liver. We also wanted to confirm that we could discriminate between tumor and liver parenchyma by DRS. The instrumentation setup consisted of a light source, a fiber-optic contact probe, and two spectrometers connected to a computer. Patients scheduled for liver resection due to hepatic malignancy were included, and DRS measurements were performed on the excised liver part with and without the liver capsule and alongside a newly cut surface. To estimate the scattering parameters and tissue chromophore volume fractions, including blood, bile, and fat, the measured diffuse reflectance spectra were applied to an analytical model. In total, 960 DRS spectra from the excised liver tissue of 18 patients were analyzed. All factors analyzed regarding tumor versus liver tissue were significantly different. When measuring through the capsule, the blood volume fraction was found to be 8.4 ± 3.5%, the lipid volume fraction was 9.9 ± 4.7%, and the bile volume fraction was 8.2 ± 4.6%. No differences could be found between surface measurements and cross-sectional measurements. In measurements with/without the liver capsule, the differences in volume fraction were 1.63% (0.75-2.77), -0.54% (-2.97 to 0.32), and -0.15% (-1.06 to 1.24) for blood, lipid, and bile, respectively. This study shows that it is possible to manage DRS

  17. Experimental Method for Measuring Dust Load on Surfaces in Rooms

    DEFF Research Database (Denmark)

    Lengweiler, Philip; Nielsen, Peter V.; Moser, Alfred

    A new experimental setup to investigate the physical process of dust deposition and resuspension on and from surfaces is introduced. Dust deposition can reduce the airborne dust concentration considerably. As a basis for developing methods to eliminate dust-related problems in rooms, there is a n......A new experimental setup to investigate the physical process of dust deposition and resuspension on and from surfaces is introduced. Dust deposition can reduce the airborne dust concentration considerably. As a basis for developing methods to eliminate dust-related problems in rooms......, there is a need for better understanding of the mechanism of dust deposition and resuspension. With the presented experimental setup, the dust load on surfaces in a channel can be measured as a function of the environmental and surface conditions and the type of particles under controlled laboratory conditions....

  18. Surface photovoltage measurements and finite element modeling of SAW devices.

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, Christine

    2012-03-01

    Over the course of a Summer 2011 internship with the MEMS department of Sandia National Laboratories, work was completed on two major projects. The first and main project of the summer involved taking surface photovoltage measurements for silicon samples, and using these measurements to determine surface recombination velocities and minority carrier diffusion lengths of the materials. The SPV method was used to fill gaps in the knowledge of material parameters that had not been determined successfully by other characterization methods. The second project involved creating a 2D finite element model of a surface acoustic wave device. A basic form of the model with the expected impedance response curve was completed, and the model is ready to be further developed for analysis of MEMS photonic resonator devices.

  19. Freeform surface measurement and characterisation using a toolmakers microscope

    International Nuclear Information System (INIS)

    Wong, Francis Seung-yin; Chauh, Kong-Bieng; Venuvinod, Patri K

    2014-01-01

    Current freeform surface (FFS) characterization systems mainly cover aspects related to computer-aided design/manufacture (CAD/CAM). This paper describes a new approach that extends into computer-aided inspection (CAI).The following novel features are addressed: - ◼ Feature recognition and extraction from surface data; - ◼ Characterisation of properties of the surface's M and N vectors at individual vertex; - ◼ Development of a measuring plan using a toolmakers microscope for the inspection of the FFS; - ◼ Inspection of the actual FFS produced by CNC milling; - ◼ Verification of the measurement results and comparison with the CAD design data; Tests have shown that the deviations between the CAI and CAD data were within the estimated uncertainty limits

  20. Thickness Measurement of Surface Attachment on Plate with Lamb Wave

    Science.gov (United States)

    Ma, Xianglong; Zhang, Yinghong; Wen, Lichao; He, Yehu

    2017-12-01

    Aiming at the thickness detection of the plate surface attachment, a nondestructive testing method based on the Lamb wave is presented. This method utilizes Lamb wave propagation characteristics of signals in a bi-layer medium to measure the surface attachment plate thickness. Propagation of Lamb wave in bi-layer elastic is modeled and analyzed. The two-dimensional simulation model of electromagnetic ultrasonic plate - scale is established. The simulation is conducted by software COMSOL for simulation analysis under different boiler scale thickness wave form curve. Through this study, the thickness of the attached material can be judged by analyzing the characteristics of the received signal when the thickness of the surface of the plate is measured.

  1. Potential Biosignificant Interest and Surface Activity of Efficient Heterocyclic Derivatives.

    Science.gov (United States)

    El-Sayed, Refat; Althagafi, Ismail

    2016-01-01

    Some functionalized pyridine and fused system derivatives were synthesized using enaminonitrile derivative 5 as a starting material for the reaction, with various reagents under different conditions. Propoxylation of these compounds using different moles of propylene oxide (3, 5 and 7 moles) leads to a novel group of surface active agents. The antimicrobial and surface activities of the synthesized compounds were investigated. Most of the evaluated compounds proved to be active as antibacterial and antifungal agents and showed good surface activity, which makes them suitable for diverse applications such as the manufacturing of emulsifiers, cosmetics, drugs, pesticides, etc. Additionally, biodegradation testing exhibits significant breakdown within six to seven days, and hence, lowers the toxicity to human beings and becomes environmentally friendly.

  2. Nuclear stimulated desorption as a potential tool for surface study

    International Nuclear Information System (INIS)

    Nir, Dror.

    1993-03-01

    The described research work constitutes a base for an experimental method to be implemented in the study of solid surfaces. Nuclear Stimulated Desorption (NSD) is a new mode of experimentation in thin film and surface physics. It Is based on the interplay between nuclear phenomena (reactions and spontaneous decays), and atomic - scale induced effects on surfaces and very thin films. One may distinguish between two generically different relationships between the two. First, the dynamics of the nuclear reaction -primarily the recoil of the nucleus - may effect the position of the atom or molecule containing it. Second, the nuclear reaction (or decay) may serve as an analytical indicator of the whereabouts of the atom, or molecule, in question. In nuclear stimulated desorption, both thee aspects combine in an essential way. Namely, one employs a series of two consecutive decays (normally weak decays or isomeric transition) . The first of these decays causes the nucleus to desorb from a surface onto which it had been placed; the second serves to determine the position of the daughter and thereby the characteristics of the primary desorption . The essential feature in NSD is that it occurs almost exclusively from the outermost surface layer. This is because we choose to work with nuclei whose recoil energy Is of the same order of magnitude of the binding energy of the atom to the surface . Furthermore, the desorption probability and its angular (and temporal) characteristics, depend on the features (topology, morphology) of its immediate neighborhood. This work describes experiments which were designed to give relevant, phenomenological information about the outgoing flux of the radioactive daughters (for specifically chosen nuclear species) , and in particular the magnitude of the flux, its time dependence and its charged state. In addition. the basic phenomena itself is being distinguished from competing processes (thermal desorption, in particular). We will now

  3. Surface moisture measurement system acceptance testing work plan

    International Nuclear Information System (INIS)

    Ritter, G.A.

    1996-01-01

    This work plan addresses testing of the Surface Moisture Measurement System (SMMS) at the Fuels and Materials Examination Facility (FMEF). The purpose of this plan is to define the scope of work, identify organizational responsibilities, describe test control requirements, and provide estimated costs and schedule associated with acceptance testing

  4. Silicon surface barrier detectors used for liquid hydrogen density measurement

    Science.gov (United States)

    James, D. T.; Milam, J. K.; Winslett, H. B.

    1968-01-01

    Multichannel system employing a radioisotope radiation source, strontium-90, radiation detector, and a silicon surface barrier detector, measures the local density of liquid hydrogen at various levels in a storage tank. The instrument contains electronic equipment for collecting the density information, and a data handling system for processing this information.

  5. An instrument for the measurement of road surface reflection properties

    DEFF Research Database (Denmark)

    Corell, Dennis Dan; Sørensen, K.

    2017-01-01

    Road surface reflection data in the form of standard r-tables serve as input for design calculations of road lighting installations on traffic roads. However, in several countries the use of the standard r-tables has not been verified by measurement in a long period of time, while the types of road...

  6. Potential drop crack measurement systems for CANDU components

    Energy Technology Data Exchange (ETDEWEB)

    Sahney, R [Carleton Univ., Ottawa, ON (Canada)

    1994-12-31

    A project to develop an automated crack measurement system for CANDU pressure tube burst testing is currently underway. The system will utilize either Direct Current Potential Drop (DCPD) or Alternating Current Potential Drop (ACPD) techniques for crack measurement. The preliminary stage of the project involves testing and comparison of both ACPD and DCPD methods on a Zr - 2.5% Nb alloy plate with saw cuts (used to simulate cracks). Preliminary results show that both ACPD and DCPD techniques are capable of detecting cracks; further testing is in progress to determine the ability of each of the two systems to make accurate crack depth measurements. This paper will describe the two potential drop techniques and will present test results from the experimental program. (author). 10 refs., 7 figs.

  7. Measuring the surface-heating of medical ultrasonic probes

    International Nuclear Information System (INIS)

    Kollmann, Chr; Vacariu, G; Fialka-Moser, V; Bergmann, H

    2004-01-01

    Due to converting losses the probe's surface itself is heated up, especially when emitting into air. Possible temperature increases in an ensemble of 15 different diagnostic and therapeutic ultrasound probes from 7 manufacturers in the frequency range between 0.05-7.5 MHz have been examined. Surface temperatures were detected by means of a calibrated IR-thermographic camera using a scheme of various power and pulse settings, as well as different imaging modalitites as used in clinical routine. Depending on the setup and the output power, the absolute surface temperatures of some of the probes emitting in air can be beyond 43 deg. C within 5-7 min.; a maximum surface temperature of 84 deg. C has been detected. Continuous mode or high pulse repetition frequencies on the therapeutic system side, small focused Doppler modes on the diagnostic system side combined with increased emitted acoustic intensities result in high surface temperatures. Within a worst case scenario a potential risk of negative skin changes (heat damage) or non-optimal therapeutic effects seems to be possible if a therapeutic system is used very often and if its emission continues unintentionally. In general the user should be aware that low emission intensities of e.g. 50 mW cm -2 could already produce hot surfaces

  8. Development of measurement standards for verifying functional performance of surface texture measuring instruments

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, A [Life and Industrial Product Development Department Olympus Corporation, 2951 Ishikawa-machi, Hachiouji-shi, Tokyo (Japan); Suzuki, H [Industrial Marketing and Planning Department Olympus Corporation, Shinjyuku Monolith, 3-1 Nishi-Shinjyuku 2-chome, Tokyo (Japan); Yanagi, K, E-mail: a_fujii@ot.olympus.co.jp [Department of Mechanical Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka-machi, Nagaoka-shi, Niigata (Japan)

    2011-08-19

    A new measurement standard is proposed for verifying overall functional performance of surface texture measuring instruments. Its surface is composed of sinusoidal surface waveforms of chirp signals along horizontal cross sections of the material measure. One of the notable features is that the amplitude of each cycle in the chirp signal form is geometrically modulated so that the maximum slope is kept constant. The maximum slope of the chirp-like signal is gradually decreased according to movement in the lateral direction. We fabricated the measurement standard by FIB processing, and it was calibrated by AFM. We tried to evaluate the functional performance of Laser Scanning Microscope by this standard in terms of amplitude response with varying slope angles. As a result, it was concluded that the proposed standard can easily evaluate the performance of surface texture measuring instruments.

  9. Seafloor geodesy: Measuring surface deformation and strain-build up

    Science.gov (United States)

    Kopp, Heidrun; Lange, Dietrich; Hannemann, Katrin; Petersen, Florian

    2017-04-01

    Seafloor deformation is intrinsically related to tectonic processes, which potentially may evolve into geohazards, including earthquakes and tsunamis. The nascent scientific field of seafloor geodesy provides a way to monitor crustal deformation at high resolution comparable to the satellite-based GPS technique upon which terrestrial geodesy is largely based. The measurements extract information on stress and elastic strain stored in the oceanic crust. Horizontal seafloor displacement can be obtained by acoustic/GPS combination to provide absolute positioning or by long-term acoustic telemetry between different beacons fixed on the seafloor. The GeoSEA (Geodetic Earthquake Observatory on the SEAfloor) array uses acoustic telemetry for relative positioning at mm-scale resolution. The transponders within an array intercommunicate via acoustic signals for a period of up to 3.5 years. The seafloor acoustic transponders are mounted on 4 m high tripod steel frames to ensure clear line-of-sight between the stations. The transponders also include high-precision pressure sensors to monitor vertical movements and dual-axis inclinometers in order to measure their level as well as any tilt of the seafloor. Sound velocity sensor measurements are used to correct for water sound speed variations. A further component of the network is GeoSURF, a self-steering autonomous surface vehicle (Wave Glider), which monitors system health and is able to upload the seafloor data to the sea surface and to transfer it via satellite. The GeoSEA array is capable of both continuously monitoring horizontal and vertical ground displacement rates along submarine fault zones and characterizing their behavior (locked or aseismically creeping). Seafloor transponders are currently installed along the Siliviri segment of the North Anatolian Fault offshore Istanbul for measurements of strain build-up along the fault. The first 18 month of baseline ranging were analyzed by a joint-least square inversion

  10. Actively stabilized optical fiber interferometry technique for online/in-process surface measurement

    International Nuclear Information System (INIS)

    Wang Kaiwei; Martin, Haydn; Jiang Xiangqian

    2008-01-01

    In this paper, we report the recent progress in optical-beam scanning fiber interferometry for potential online nanoscale surface measurement based on the previous research. It attempts to generate a robust and miniature measurement device for future development into a multiprobe array measurement system. In this research, both fiber-optic-interferometry and the wavelength-division-multiplexing techniques have been used, so that the optical probe and the optical interferometer are well spaced and fast surface scanning can be carried out, allowing flexibility for online measurement. In addition, this system provides a self-reference signal to stabilize the optical detection with high common-mode noise suppression by adopting an active phase tracking and stabilization technique. Low-frequency noise was significantly reduced compared with unstabilized result. The measurement of a sample surface shows an attained repeatability of 3.3 nm

  11. Influence of the Ambient Electric Field on Measurements of the Actively Controlled Spacecraft Potential by MMS

    Science.gov (United States)

    Torkar, K.; Nakamura, R.; Andriopoulou, M.; Giles, B. L.; Jeszenszky, H.; Khotyaintsev, Y. V.; Lindqvist, P.-A.; Torbert, R. B.

    2017-12-01

    Space missions with sophisticated plasma instrumentation such as Magnetospheric Multiscale, which employs four satellites to explore near-Earth space benefit from a low electric potential of the spacecraft, to improve the plasma measurements and therefore carry instruments to actively control the potential by means of ion beams. Without control, the potential varies in anticorrelation with plasma density and temperature to maintain an equilibrium between the plasma current and the one of photoelectrons produced at the surface and overcoming the potential barrier. A drawback of the controlled, almost constant potential is the difficulty to use it as convenient estimator for plasma density. This paper identifies a correlation between the spacecraft potential and the ambient electric field, both measured by double probes mounted at the end of wire booms, as the main responsible for artifacts in the potential data besides the known effect of the variable photoelectron production due to changing illumination of the surface. It is shown that the effect of density variations is too weak to explain the observed correlation with the electric field and that a correction of the artifacts can be achieved to enable the reconstruction of the uncontrolled potential and plasma density in turn. Two possible mechanisms are discussed: the asymmetry of the current-voltage characteristic determining the probe to plasma potential and the fact that a large equipotential structure embedded in an electric field results in asymmetries of both the emission and spatial distribution of photoelectrons, which results in an increase of the spacecraft potential.

  12. Remote measurement of surface roughness, surface reflectance, and body reflectance with LiDAR.

    Science.gov (United States)

    Li, Xiaolu; Liang, Yu

    2015-10-20

    Light detection and ranging (LiDAR) intensity data are attracting increasing attention because of the great potential for use of such data in a variety of remote sensing applications. To fully investigate the data potential for target classification and identification, we carried out a series of experiments with typical urban building materials and employed our reconstructed built-in-lab LiDAR system. Received intensity data were analyzed on the basis of the derived bidirectional reflectance distribution function (BRDF) model and the established integration method. With an improved fitting algorithm, parameters involved in the BRDF model can be obtained to depict the surface characteristics. One of these parameters related to surface roughness was converted to a most used roughness parameter, the arithmetical mean deviation of the roughness profile (Ra), which can be used to validate the feasibility of the BRDF model in surface characterizations and performance evaluations.

  13. Fasciculation potentials in high-density surface EMG.

    NARCIS (Netherlands)

    Drost, G.; Kleine, B.U.; Stegeman, D.F.; Engelen, B.G.M. van; Zwarts, M.J.

    2007-01-01

    Fasciculation potentials (FPs) are observed in healthy individuals, but also in patients with neurogenic disorders. The exact site of origin and the clinical relevance in distinguishing, for example, amyotrophic lateral sclerosis (ALS) from other neurogenic diseases based on specific characteristics

  14. An experimental method for making spectral emittance and surface temperature measurements of opaque surfaces

    International Nuclear Information System (INIS)

    Moore, Travis J.; Jones, Matthew R.; Tree, Dale R.; Daniel Maynes, R.; Baxter, Larry L.

    2011-01-01

    An experimental procedure has been developed to make spectral emittance and temperature measurements. The spectral emittance of an object is calculated using measurements of the spectral emissive power and of the surface temperature of the object obtained using a Fourier transform infrared (FTIR) spectrometer. A calibration procedure is described in detail which accounts for the temperature dependence of the detector. The methods used to extract the spectral emissive power and surface temperature from measured infrared spectra were validated using a blackbody radiator at known temperatures. The average error in the measured spectral emittance was 2.1% and the average difference between the temperature inferred from the recorded spectra and the temperature indicated on the blackbody radiator was 1.2%. The method was used to measure the spectral emittance of oxidized copper at various temperatures.

  15. Effect of potential attraction term on surface tension of ionic liquids

    Science.gov (United States)

    Vaziri, N.; Khordad, R.; Rezaei, G.

    2018-03-01

    In this work, we have studied the effect of attraction term of molecular potential on surface tension of ionic liquids (ILs). For this purpose, we have introduced two different potential models to obtain analytical expressions for the surface tension of ILs. The introduced potential models have different attraction terms. The obtained surface tensions in this work have been compared with other theoretical methods and also experimental data. Using the calculated surface tension, the sound velocity is also estimated. We have studied the structural effects on the surface tensions of imidazolium-based ionic liquids. It is found that the cation alkyl chain length and the anion size play important roles to the surface tension of the selected ionic liquids. The calculated surface tensions show a good harmony with experimental data. It is clear that the attraction term of molecular potential has an important role on surface tension and sound velocity of our system.

  16. Wireless Sensor Node for Surface Seawater Density Measurements

    Directory of Open Access Journals (Sweden)

    Roberto Saletti

    2012-03-01

    Full Text Available An electronic meter to measure surface seawater density is presented. It is based on the measurement of the difference in displacements of a surface level probe and a weighted float, which according to Archimedes’ law depends on the density of the water. The displacements are simultaneously measured using a high-accuracy magnetostrictive sensor, to which a custom electronic board provides a wireless connection and power supply so that it can become part of a wireless sensor network. The electronics are designed so that different kinds of wireless networks can be used, by simply changing the wireless module and the relevant firmware of the microcontroller. Lastly, laboratory and at-sea tests are presented and discussed in order to highlight the functionality and the performance of a prototype of the wireless density meter node in a Bluetooth radio network. The experimental results show a good agreement of the values of the calculated density compared to reference hydrometer readings.

  17. Wireless sensor node for surface seawater density measurements.

    Science.gov (United States)

    Baronti, Federico; Fantechi, Gabriele; Roncella, Roberto; Saletti, Roberto

    2012-01-01

    An electronic meter to measure surface seawater density is presented. It is based on the measurement of the difference in displacements of a surface level probe and a weighted float, which according to Archimedes' law depends on the density of the water. The displacements are simultaneously measured using a high-accuracy magnetostrictive sensor, to which a custom electronic board provides a wireless connection and power supply so that it can become part of a wireless sensor network. The electronics are designed so that different kinds of wireless networks can be used, by simply changing the wireless module and the relevant firmware of the microcontroller. Lastly, laboratory and at-sea tests are presented and discussed in order to highlight the functionality and the performance of a prototype of the wireless density meter node in a Bluetooth radio network. The experimental results show a good agreement of the values of the calculated density compared to reference hydrometer readings.

  18. Field Measurement of Surface Ship Magnetic Signature Using Multiple AUVs

    Science.gov (United States)

    2009-10-01

    been equipped with a tri-axial fluxgate magnetometer and used to perform preliminary magnetic field measurements. Measurements of this type will be...mounted on the AUVs, shown in Fig. 1, was a three-axis fluxgate type [16] magnetometer with a range of ±100,000 nT and a sensitivity of 100μV/nT. The...surface ship. The system will employ a formation of multiple AUVs, each equipped with a magnetometer . The objective is to measure total magnetic

  19. Measurement of annual dose on porcelain using surface TLD method

    International Nuclear Information System (INIS)

    Xia Junding; Wang Weida; Leung, P.L.

    2001-01-01

    In order to improve accuracy of TL authentication test for porcelain, a method of measurement of annual dose using ultrathin (CaSO 4 :Tm) dosage layer on porcelain was studied. The TLD was placed on the part of porcelain without glaze. A comparison of measurement of annual dose for surface TLD, inside TLD and alpha counting on porcelain was made. The results show that this technique is suitable for measuring annual dose and improving accuracy of TL authentication test for both porcelain and pottery

  20. In vivo measurement of vocal fold surface resistance.

    Science.gov (United States)

    Mizuta, Masanobu; Kurita, Takashi; Dillon, Neal P; Kimball, Emily E; Garrett, C Gaelyn; Sivasankar, M Preeti; Webster, Robert J; Rousseau, Bernard

    2017-10-01

    A custom-designed probe was developed to measure vocal fold surface resistance in vivo. The purpose of this study was to demonstrate proof of concept of using vocal fold surface resistance as a proxy of functional tissue integrity after acute phonotrauma using an animal model. Prospective animal study. New Zealand White breeder rabbits received 120 minutes of airflow without vocal fold approximation (control) or 120 minutes of raised intensity phonation (experimental). The probe was inserted via laryngoscope and placed on the left vocal fold under endoscopic visualization. Vocal fold surface resistance of the middle one-third of the vocal fold was measured after 0 (baseline), 60, and 120 minutes of phonation. After the phonation procedure, the larynx was harvested and prepared for transmission electron microscopy. In the control group, vocal fold surface resistance values remained stable across time points. In the experimental group, surface resistance (X% ± Y% relative to baseline) was significantly decreased after 120 minutes of raised intensity phonation. This was associated with structural changes using transmission electron microscopy, which revealed damage to the vocal fold epithelium after phonotrauma, including disruption of the epithelium and basement membrane, dilated paracellular spaces, and alterations to epithelial microprojections. In contrast, control vocal fold specimens showed well-preserved stratified squamous epithelia. These data demonstrate the feasibility of measuring vocal fold surface resistance in vivo as a means of evaluating functional vocal fold epithelial barrier integrity. Device prototypes are in development for additional testing, validation, and for clinical applications in laryngology. NA Laryngoscope, 127:E364-E370, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

  1. Influence of beverage composition on the results of erosive potential measurement by different measurement techniques

    NARCIS (Netherlands)

    Jager, D. H. J.; Vieira, A. M.; Ruben, J. L.; Huysmans, M. C. D. N. J. M.

    2008-01-01

    The influence of beverage composition on the measurement of erosive potential is unclear. The aim of this study was to evaluate whether beverage composition influences the measurement of erosive potential and to evaluate the influence of exposure in small and large volumes. Eleven beverages were

  2. Influence of beverage composition on the results of erosive potential measurement by different measurement techniques.

    NARCIS (Netherlands)

    Jager, D.H.; Vieira, A.M.; Ruben, J.L.; Huysmans, M.C.D.N.J.M.

    2008-01-01

    The influence of beverage composition on the measurement of erosive potential is unclear. The aim of this study was to evaluate whether beverage composition influences the measurement of erosive potential and to evaluate the influence of exposure in small and large volumes. Eleven beverages were

  3. DNA conformation on surfaces measured by fluorescence self-interference.

    Science.gov (United States)

    Moiseev, Lev; Unlü, M Selim; Swan, Anna K; Goldberg, Bennett B; Cantor, Charles R

    2006-02-21

    The conformation of DNA molecules tethered to the surface of a microarray may significantly affect the efficiency of hybridization. Although a number of methods have been applied to determine the structure of the DNA layer, they are not very sensitive to variations in the shape of DNA molecules. Here we describe the application of an interferometric technique called spectral self-interference fluorescence microscopy to the precise measurement of the average location of a fluorescent label in a DNA layer relative to the surface and thus determine specific information on the conformation of the surface-bound DNA molecules. Using spectral self-interference fluorescence microscopy, we have estimated the shape of coiled single-stranded DNA, the average tilt of double-stranded DNA of different lengths, and the amount of hybridization. The data provide important proofs of concept for the capabilities of novel optical surface analytical methods of the molecular disposition of DNA on surfaces. The determination of DNA conformations on surfaces and hybridization behavior provide information required to move DNA interfacial applications forward and thus impact emerging clinical and biotechnological fields.

  4. A new surface resistance measurement method with ultrahigh sensitivity

    International Nuclear Information System (INIS)

    Liang, Changnian.

    1993-01-01

    A superconducting niobium triaxial cavity has been designed and fabricated to study residual surface resistance of planar superconducting materials. The edge of a 25.4 mm or larger diameter sample in the triaxial cavity is located outside the strong field region. Therefore, the edge effects and possible losses between the thin film and the substrate have been minimized, ensuring that induced RF losses are intrinsic to the test material. The fundamental resonant frequency of the cavity is the same as the working frequency of CEBAF cavities. The cavity has a compact size compared to its TE 011 counterpart, which makes it more sensitive to the sample's loss. For even higher sensitivity, a calorimetry method has been used to measure the RF losses on the superconducting sample. At 2 K, a 2 μK temperature change can be resolved by using carbon resistor sensors. The temperature distribution caused by RF heating is measured by 16 carbon composition resistor sensors. A 0.05 μW heating power can be detected as such a resolution, which translates to a surface resistance of 0.02 nΩ at a surface magnetic field of 52 Oe. This is the most sensitive device for surface resistance measurements to date. In addition, losses due to the indium seal, coupling probes, field emission sites other than the sample, and all of the high field resonator surface, are excluded in the measurement. Surface resistance of both niobium and high-Tc superconducting thin films has been measured. A low R s of 35.2 μΩ was measured for a 25.4 mm diameter YBa 2 Cu 3 O 7 thin film at 1.5 GHz and at 2 K. The measurement result is the first result for a large area epitaxially grown thin film sample at such a low RF frequency. The abrupt disappearance of multipacting between two parallel plates has been observed and monitored with the 16 temperature mapping sensors. Field emission or some field dependent anomalous RF losses on the niobium plate have also been observed

  5. Measurements of the near-surface flow over a hill

    Science.gov (United States)

    Vosper, S. B.; Mobbs, S. D.; Gardiner, B. A.

    2002-10-01

    The near-surface flow over a hill with moderate slope and height comparable with the boundary-layer depth is investigated through field measurements of the mean flow (at 2 m), surface pressure, and turbulent momentum flux divergence between 8 and 15 m. The measurements were made along an east-west transect across the hill Tighvein (height 458 m, approximate width 8 km) on the Isle of Arran, south-west Scotland, during two separate periods, each of around three-weeks duration. Radiosonde ascents are used to determine the variation of a Froude number, FL = U/NL, where U is the wind speed at the middle-layer height, hm, N is the mean Brunt-Väisälä frequency below this height and L is a hill length-scale. Measurements show that for moderately stratified flows (for which FL 0.25) a minimum in the hill-induced surface-pressure perturbation occurs across the summit and this is accompanied by a maximum in the near-surface wind speed. In the more strongly stratified case (FL 0.25) the pressure field is more asymmetric and the lee-slope flow is generally stronger than on the windward slope. Such a flow pattern is qualitatively consistent with that predicted by stratified linear boundary-layer and gravity-wave theories. The near-surface momentum budget is analysed by evaluating the dominant terms in a Bernoulli equation suitable for turbulent flow. Measurements during periods of westerly flow are used to evaluate the dominant terms, and the equation is shown to hold to a reasonable approximation on the upwind slope of the hill and also on the downwind slope, away from the summit. Immediately downwind of the summit, however, the Bernoulli equation does not hold. Possible reasons for this, such as non-separated sheltering and flow separation, are discussed.

  6. Potential controls of isoprene in the surface ocean

    Science.gov (United States)

    Hackenberg, S. C.; Andrews, S. J.; Airs, R.; Arnold, S. R.; Bouman, H. A.; Brewin, R. J. W.; Chance, R. J.; Cummings, D.; Dall'Olmo, G.; Lewis, A. C.; Minaeian, J. K.; Reifel, K. M.; Small, A.; Tarran, G. A.; Tilstone, G. H.; Carpenter, L. J.

    2017-04-01

    Isoprene surface ocean concentrations and vertical distribution, atmospheric mixing ratios, and calculated sea-to-air fluxes spanning approximately 125° of latitude (80°N-45°S) over the Arctic and Atlantic Oceans are reported. Oceanic isoprene concentrations were associated with a number of concurrently monitored biological variables including chlorophyll a (Chl a), photoprotective pigments, integrated primary production (intPP), and cyanobacterial cell counts, with higher isoprene concentrations relative to all respective variables found at sea surface temperatures greater than 20°C. The correlation between isoprene and the sum of photoprotective carotenoids, which is reported here for the first time, was the most consistent across all cruises. Parameterizations based on linear regression analyses of these relationships perform well for Arctic and Atlantic data, producing a better fit to observations than an existing Chl a-based parameterization. Global extrapolation of isoprene surface water concentrations using satellite-derived Chl a and intPP reproduced general trends in the in situ data and absolute values within a factor of 2 between 60% and 85%, depending on the data set and algorithm used.

  7. Methods for direct measurement of the plasma potential

    DEFF Research Database (Denmark)

    Andersen, S. A.; Christoffersen, G. B.; Jensen, Vagn Orla

    1972-01-01

    Reports on a simple experimental technique which can be used for determination of the plasma where the plasma potential prevails; these ions are accepted by the analyser plate when phi c= phi pl. Part of this technique has been used by Andersen, Jensen, Michelsen and Nielsen (1971) in measurements...

  8. Simultaneous measurements of top surface and its underlying film surfaces in multilayer film structure.

    Science.gov (United States)

    Ghim, Young-Sik; Rhee, Hyug-Gyo; Davies, Angela

    2017-09-19

    With the growth of 3D packaging technology and the development of flexible, transparent electrodes, the use of multilayer thin-films is steadily increasing throughout high-tech industries including semiconductor, flat panel display, and solar photovoltaic industries. Also, this in turn leads to an increase in industrial demands for inspection of internal analysis. However, there still remain many technical limitations to overcome for measurement of the internal structure of the specimen without damage. In this paper, we propose an innovative optical inspection technique for simultaneous measurements of the surface and film thickness corresponding to each layer of multilayer film structures by computing the phase and reflectance over a wide range of wavelengths. For verification of our proposed method, the sample specimen of multilayer films was fabricated via photolithography process, and the surface profile and film thickness of each layer were measured by two different techniques of a stylus profilometer and an ellipsometer, respectively. Comparison results shows that our proposed technique enables simultaneous measurements of the top surface and its underlying film surfaces with high precision, which could not be measured by conventional non-destructive methods.

  9. Automatic measurement for monitoring crack growth with electric potential technique

    International Nuclear Information System (INIS)

    Nakajima, Nobuya; Kikuchi, Masaaki; Shima, Seishi

    1981-10-01

    In the study of fracture mechanics, it is one of the most important problems to monitor the crack growth phenomena. Recently, many experimental methods have been developed. In this report, the Direct Current (DC) potential method is employed for measuring the crack growth length in the pressuried high temperature water. The objective of the current investigation is to develop an experimental method to quantify the sensitivity of this method in the air environment using the Compact Tension (CT) specimen. The main results obtained are as follows: 1) It is ignored that the electrical potential changes with plastic deformation at the crack tip of the specimen. 2) Using the Reversible Direct Current (RDC) Method, the measurement system gives no effect on the electrical stability for a long time. 3) For the fatigue and statical crack growth length, good relation is observed between the crack length-to-specimen width ratio (a/W) and potential ratio (Va/Vo). (author)

  10. Airborne spectral measurements of surface anisotropy during SCAR-B

    Science.gov (United States)

    Tsay, Si-Chee; King, Michael D.; Arnold, G. Thomas; Li, Jason Y.

    1998-12-01

    During the Smoke, Clouds, and Radiation-Brazil (SCAR-B) deployment, angular distributions of spectral reflectance for vegetated surfaces and smoke layers were measured using the scanning cloud absorption radiometer (CAR) mounted on the University of Washington C-131A research aircraft. The CAR contains 13 narrowband spectral channels between 0.3 and 2.3 μm with a 190° scan aperture (5° before zenith to 5° past nadir) and 1° instantaneous field of view. The bidirectional reflectance is obtained by flying a clockwise circular orbit above the surface, resulting in a ground track ˜3 km in diameter within about 2 min. Although the CAR measurements are contaminated by minor atmospheric effects, results show distinct spectral characteristics for various types of surfaces. Spectral bidirectional reflectances of three simple and well-defined surfaces are presented: cerrado (August 18, 1995) and dense forest (August 25, 1995), both measured in Brazil under nearly clear-sky conditions, and thick smoke layers over dense forest (September 6 and 11, 1995). The bidirectional reflectances of cerrado and dense forest revealed fairly symmetric patterns along the principal plane, with varying maximal strengths and widths spectrally in the backscattering direction. In the shortwave-infrared region the aerosol effect is very small due to low spectral optical depth. Also, these backscattering maxima can be seen on the bidirectional reflectance of smoke layer over dense forest. These detailed measurements of the angular distribution of spectral reflectance can be parameterized by a few independent variables and utilized to retrieve either surface characteristics or aerosol microphysical and optical properties (e.g., size distribution and single-scattering parameters), if proper physical and radiation models are used. The spectral-hemispherical albedo of these surfaces is obtained directly by integrating all angular measurements and is compared with the measured nadir reflectance

  11. The size prediction of potential inclusions embedded in the sub-surface of fused silica by damage morphology

    Directory of Open Access Journals (Sweden)

    Gao Xiang

    2017-04-01

    Full Text Available A model for predicting the size ranges of different potential inclusions initiating damage on the surface of fused silica has been presented. This accounts for the heating of nanometric inclusions whose absorptivity is described based on Mie Theory. The depth profile of impurities has been measured by ICP-OES. By the measured temporal pulse profile on the surface of fused silica, the temperature and thermal stress has been calculated. Furthermore, considering the limit conditions of temperature and thermal stress strength for different damage morphologies, the size range of potential inclusions for fused silica is discussed.

  12. Surface chemistry dependent immunostimulative potential of porous silicon nanoplatforms.

    Science.gov (United States)

    Shahbazi, Mohammad-Ali; Fernández, Tahia D; Mäkilä, Ermei M; Le Guével, Xavier; Mayorga, Cristobalina; Kaasalainen, Martti H; Salonen, Jarno J; Hirvonen, Jouni T; Santos, Hélder A

    2014-11-01

    Nanoparticles (NPs) have been suggested for immunotherapy applications in order to optimize the delivery of immuno-stimulative or -suppressive molecules. However, low attention towards the impact of the NPs' physicochemical properties has presented a major hurdle for developing efficient immunotherapeutic agents. Here, the effects of porous silicon (PSi) NPs with different surface chemistries were evaluated on human monocyte-derived dendritic cells (MDDCs) and lymphocytes in order to highlight the importance of the NPs selection in immuno-stimulative or -suppressive treatment. Although all the PSi NPs showed high biocompatibility, only thermally oxidized PSi (TOPSi) and thermally hydrocarbonized PSi (THCPSi) NPs were able to induce very high rate of immunoactivation by enhancing the expression of surface co-stimulatory markers of the MDDCs (CD80, CD83, CD86, and HLA-DR), inducing T-cell proliferation, and also the secretion of interleukins (IL-1β, IL-4, IL-6, IL-10, IL-12, IFN-γ, and TNF-α). These results indicated a balanced increase in the secretion of Th1, Th2, and Treg cytokines. Moreover, undecylenic acid functionalized THCPSi, as well as poly(methyl vinyl ether-alt-maleic acid) conjugated to (3-aminopropyl)triethoxysilane functionalized thermally carbonized PSi and polyethyleneimine conjugated undecylenic acid functionalized THCPSi NPs showed moderate immunoactivation due to the mild increase in the above-mentioned markers. By contrast, thermally carbonized PSi (TCPSi) and (3-aminopropyl)triethoxysilane functionalized TCPSi NPs did not induce any immunological responses, suggesting that their application could be in the delivery of immunosuppressive molecules. Overall, our findings suggest all the NPs containing more nitrogen or oxygen on the outermost backbone layer have lower immunostimulatory effect than NPs with higher C-H structures on the surface. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Extension of a He-H2 potential energy surface

    International Nuclear Information System (INIS)

    Raczkowski, A.W.; Lester, W.A. Jr.

    1977-01-01

    The CI surface of Tsapline and Kutzelnigg is extended to smaller H 2 -He separations. Defining R as the H 2 -He distance, r as the H 2 separation, and γ as the angle between them, the ab initio values are fit to a Legendre series in cosγ retaining the first three (even) terms with the coefficients given as analytic functions of R and r to facilitate semiclassical scattering computations. The fit is quantitative for 1.0 approximately r/2+1. (Auth.)

  14. THE EFFECTS OF CRACKING ON THE SURFACE POTENTIAL OF ICY GRAINS IN SATURN’S E-RING: LABORATORY STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Caixia; Bahr, David A.; Dukes, Catherine A.; Baragiola, Raúl A., E-mail: cb8nw@virginia.edu [Laboratory for Astrophysics and Surface Physics, Materials Science and Engineering, University of Virginia, Charlottesville, VA 22904 (United States)

    2016-07-10

    Within Saturn's E-ring, dust grains are coated by water vapor co-released with ice grains from the geyser-like eruptions of Enceladus. These ice-coated grains have intrinsic surface potential and interact synergistically with the ions and electrons of Saturn's magnetospheric plasmas. We perform laboratory experiments to investigate the effects of water-ice growth on the surface potential, using amorphous solid water (ASW) films. We estimate the growth of the surface potential to be ∼ 2.5 mV (Earth) yr{sup 1} and 112 mV yr{sup 1} for E-ring grains at ∼4.5 R {sub s} and 3.95 R {sub s} outside Enceladus’s plume, respectively. In addition, our measurements show that the linear relationship between the surface potential and the film thickness, as described in previous studies, has an upper limit, where the film spontaneously cracks above a porosity-dependent critical thickness. Heating of the cracked films with (and without) deposited charge shows that significant positive (and negative) surface potentials are retained at temperatures above 110 K, contrary to the minimal values (roughly zero) for thin, transparent ASW films. The significant surface potentials observed on micron-scale cracked ice films after thermal cycling, (5–20) V, are consistent with Cassini measurements, which indicate a negative charge of up to 5 V for E-ring dust particles at ∼5 R {sub s}. Therefore, the native grain surface potential resulting from water-vapor coating must be included in modeling studies of interactions between E-ring icy surfaces and Saturn's magnetospheric plasma.

  15. An accurate global potential energy surface, dipole moment surface, and rovibrational frequencies for NH3

    Science.gov (United States)

    Huang, Xinchuan; Schwenke, David W.; Lee, Timothy J.

    2008-12-01

    A global potential energy surface (PES) that includes short and long range terms has been determined for the NH3 molecule. The singles and doubles coupled-cluster method that includes a perturbational estimate of connected triple excitations and the internally contracted averaged coupled-pair functional electronic structure methods have been used in conjunction with very large correlation-consistent basis sets, including diffuse functions. Extrapolation to the one-particle basis set limit was performed and core correlation and scalar relativistic contributions were included directly, while the diagonal Born-Oppenheimer correction was added. Our best purely ab initio PES, denoted "mixed," is constructed from two PESs which differ in whether the ic-ACPF higher-order correlation correction was added or not. Rovibrational transition energies computed from the mixed PES agree well with experiment and the best previous theoretical studies, but most importantly the quality does not deteriorate even up to 10300cm-1 above the zero-point energy (ZPE). The mixed PES was improved further by empirical refinement using the most reliable J =0-2 rovibrational transitions in the HITRAN 2004 database. Agreement between high-resolution experiment and rovibrational transition energies computed from our refined PES for J =0-6 is excellent. Indeed, the root mean square (rms) error for 13 HITRAN 2004 bands for J =0-2 is 0.023cm-1 and that for each band is always ⩽0.06cm-1. For J =3-5 the rms error is always ⩽0.15cm-1. This agreement means that transition energies computed with our refined PES should be useful in the assignment of new high-resolution NH3 spectra and in correcting mistakes in previous assignments. Ideas for further improvements to our refined PES and for extension to other isotopolog are discussed.

  16. Magnetic flux surface measurements at the Wendelstein 7-X stellarator

    Energy Technology Data Exchange (ETDEWEB)

    Otte, Matthias; Andreeva, Tamara; Biedermann, Christoph; Bozhenkov, Sergey; Geiger, Joachim; Sunn Pedersen, Thomas [Max-Planck-Institut fuer Plasmaphysik, Greifswald (Germany); Lazerson, Samuel [Princeton Plasma Physics Laboratory, Princeton (United States)

    2016-07-01

    Recently the first plasma operation phase of the Wendelstein 7-X stellarator has been started at IPP Greifswald. Wendelstein 7-X is an optimized stellarator with a complex superconducting magnet system consisting of 50 non-planar and 20 planar field coils and further 10 normal conducting control and 5 trim coils. The magnetic confinement and hence the expected plasma performance are decisively determined by the properties of the magnet system, especially by the existence and quality of the magnetic flux surfaces. Even small error fields may result in significant changes of the flux surface topology. Therefore, measurements of the vacuum magnetic flux surfaces have been performed before plasma operation. The first experimental results confirm the existence and quality of the flux surfaces to the full extend from low field up to the nominal field strength of B=2.5T. This includes the dedicated magnetic limiter configuration that is exclusively used for the first plasma operation. Furthermore, the measurements are indicating that the intrinsic error fields are within the tolerable range and can be controlled utilizing the trim coils as expected.

  17. Surface albedo measurements in Mexico City metropolitan area

    Energy Technology Data Exchange (ETDEWEB)

    Castro, T; Mar, B; Longoria, R; Ruiz Suarez, L. G [Centro de Ciencias de la Atmosfera, UNAM, Mexico, D.F. (Mexico); Morales, L [Instituto de Geografia, UNAM, Mexico, D.F. (Mexico)

    2001-04-01

    Optical and thermal properties of soils are important input data for the meteorological and photochemical modules of air quality models. As development of these models increase on spatial resolution good albedo data become more important. In this paper measurements of surface albedo of UV (295-385 nm) and visible (450-550 nm) radiation are reported for different urban and rural surfaces in the vicinity of Mexico City. It was found for the downtown zone and average albedo value of 0.05 which is in very good agreement with reported values for urban surfaces. Our albedo values measured in UV region for grey cement and green grass are of 0.10 and 0.009, respectively, and quite similar to those found at the literature of 0.11 and 0.008 for those type of surfaces. [Spanish] Las propiedades opticas y termicas de suelos son datos importantes para los modulos meteorologicos y fotoquimicos de los modelos de calidad del aire. Conforme aumenta la resolucion espacial del modelo se vuelve mas importante contar con buenos datos de albedo. En este articulo se presentan mediciones de albedo superficial de radiacion Ultravioleta (295-385 nm) y visible (450-550 nm) para diferentes superficies urbanas. Los valores medidos de albedo en la region UV para cemento gris y pasto verde son de 0.10 y 0.009, respectivamente, y son muy similares a los reportados en la literatura, 0.11 y 0.008 para este tipo de superficies.

  18. Calculation of surface potentials at the silica–water interface using molecular dynamics: Challenges and opportunities

    Science.gov (United States)

    Lowe, Benjamin M.; Skylaris, Chris-Kriton; Green, Nicolas G.; Shibuta, Yasushi; Sakata, Toshiya

    2018-04-01

    Continuum-based methods are important in calculating electrostatic properties of interfacial systems such as the electric field and surface potential but are incapable of providing sufficient insight into a range of fundamentally and technologically important phenomena which occur at atomistic length-scales. In this work a molecular dynamics methodology is presented for interfacial electric field and potential calculations. The silica–water interface was chosen as an example system, which is highly relevant for understanding the response of field-effect transistors sensors (FET sensors). Detailed validation work is presented, followed by the simulated surface charge/surface potential relationship. This showed good agreement with experiment at low surface charge density but at high surface charge density the results highlighted challenges presented by an atomistic definition of the surface potential. This methodology will be used to investigate the effect of surface morphology and biomolecule addition; both factors which are challenging using conventional continuum models.

  19. Change of the work function and potential barrier transparency of W(100) and GaAs(110) single crystals during removing the inherent surface oxide layer

    International Nuclear Information System (INIS)

    Asalkhanov, Yu.I.; Saneev, Eh.L.

    2002-01-01

    Changes of current voltage characteristics of slow monoenergetic electron beam through the surfaces of W(100) and GaAs(100) single crystals have been measured in the process of surface oxide layers elimination. It is shown that work function is decreased and transparency coefficient of surface potential barrier is increased under increasing the temperature of vacuum annealing. Peculiarities of surface potential change under oxide layer elimination in metals and semiconductors are discussed [ru

  20. Surface and zeta-potentials of silver halide single crystals: pH-dependence in comparison to particle systems

    International Nuclear Information System (INIS)

    Selmani, Atiða; Kallay, Nikola; Preočanin, Tajana; Lützenkirchen, Johannes

    2014-01-01

    We have carried out surface and zeta-potential measurements on AgCl and AgBr single crystals. As for particle systems we find that, surprisingly and previously unnoted, the zeta-potential exhibits pH-dependence, while the surface potential does not. A possible interpretation of these observations is the involvement of water ions in the interfacial equilibria and in particular, stronger affinity of the hydroxide ion compared to the proton. The pH-dependence of the zeta-potential can be suppressed at sufficiently high silver concentrations, which agrees with previous measurements in particle systems where no pH-dependence was found at high halide ion concentrations. The results suggest a subtle interplay between the surface potential determining the halide and silver ion concentrations, and the water ions. Whenever the charge due to the halide and silver ions is sufficiently high, the influence of the proton/hydroxide ion on the zeta-potential vanishes. This might be related to the water structuring at the relevant interfaces which should be strongly affected by the surface potential. Another interesting observation is accentuation of the assumed water ion effect on the zeta-potential at the flat single crystal surfaces compared to the corresponding silver halide colloids. Previous generic MD simulations have indeed predicted that hydroxide ion adsorption is accentuated on flat/rigid surfaces. A thermodynamic model for AgI single crystals was developed to describe the combined effects of iodide, silver and water ions, based on two independently previously published models for AgI (that only consider constituent and background electrolyte ions) and inert surfaces (that only consider water and background electrolyte ions). The combined model correctly predicts all the experimentally observed trends. (paper)

  1. Attention effects at auditory periphery derived from human scalp potentials: displacement measure of potentials.

    Science.gov (United States)

    Ikeda, Kazunari; Hayashi, Akiko; Sekiguchi, Takahiro; Era, Shukichi

    2006-10-01

    It is known in humans that electrophysiological measures such as the auditory brainstem response (ABR) are difficult to identify the attention effect at the auditory periphery, whereas the centrifugal effect has been detected by measuring otoacoustic emissions. This research developed a measure responsive to the shift of human scalp potentials within a brief post-stimulus period (13 ms), that is, displacement percentage, and applied it to an experiment to retrieve the peripheral attention effect. In the present experimental paradigm, tone pips were exposed to the left ear whereas the other ear was masked by white noise. Twelve participants each conducted two conditions of either ignoring or attending to the tone pips. Relative to averaged scalp potentials in the ignoring condition, the shift of the potentials was found within early component range during the attentive condition, and displacement percentage then revealed a significant magnitude difference between the two conditions. These results suggest that, using a measure representing the potential shift itself, the peripheral effect of attention can be detected from human scalp potentials.

  2. Effective aerosol optical depth from pyranometer measurements of surface solar radiation (global radiation) at Thessaloniki, Greece

    OpenAIRE

    Lindfors, A. V.; Kouremeti, N.; Arola, A.; Kazadzis, S.; Bais, A. F.; Laaksonen, A.

    2013-01-01

    Pyranometer measurements of the solar surface radiation (SSR) are available at many locations worldwide, often as long time series covering several decades into the past. These data constitute a potential source of information on the atmospheric aerosol load. Here, we present a method for estimating the aerosol optical depth (AOD) using pyranometer measurements of the SSR together with total water vapor column information. The method, which is based on radiative transfer simulations, w...

  3. Surface moisture measurement system hardware acceptance test report

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, G.A., Westinghouse Hanford

    1996-05-28

    This document summarizes the results of the hardware acceptance test for the Surface Moisture Measurement System (SMMS). This test verified that the mechanical and electrical features of the SMMS functioned as designed and that the unit is ready for field service. The bulk of hardware testing was performed at the 306E Facility in the 300 Area and the Fuels and Materials Examination Facility in the 400 Area. The SMMS was developed primarily in support of Tank Waste Remediation System (TWRS) Safety Programs for moisture measurement in organic and ferrocyanide watch list tanks.

  4. System design description for surface moisture measurement system (SMMS)

    Energy Technology Data Exchange (ETDEWEB)

    Vargo, G.F.

    1996-09-23

    The SMMS has been developed to measure moisture in the top few centimeters of tank waste. The SMMS development was initiated by the preliminary findings of SAR-033, and does not necessarily fulfill any established DQO. After the SAR-033 is released, if no significant changes are made, moisture measurements in the organic waste tanks will rapidly become a DQO. The SMMS was designed to be installed in any 4 inch or larger riser, and to allow maximum adjustability for riser lengths, and is used to deploy a sensor package on the waste surface within a 6 foot radius about the azimuth. The first sensor package will be a neutron probe.

  5. Quantitative nanoscale surface voltage measurement on organic semiconductor blends

    International Nuclear Information System (INIS)

    Cuenat, Alexandre; Muñiz-Piniella, Andrés; Muñoz-Rojo, Miguel; Murphy, Craig E; Tsoi, Wing C

    2012-01-01

    We report on the validation of a method based on Kelvin probe force microscopy (KPFM) able to measure the different phases and the relative work function of polymer blend heterojunctions at the nanoscale. The method does not necessitate complex ultra-high vacuum setup. The quantitative information that can be extracted from the topography and the Kelvin probe measurements is critically analysed. Surface voltage difference can be observed at the nanoscale on poly(3-hexyl-thiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) blends and dependence on the annealing condition and the regio-regularity of P3HT is observed. (paper)

  6. Surface moisture measurement system hardware acceptance test procedure

    International Nuclear Information System (INIS)

    Ritter, G.A.

    1996-01-01

    The purpose of this acceptance test procedure is to verify that the mechanical and electrical features of the Surface Moisture Measurement System are operating as designed and that the unit is ready for field service. This procedure will be used in conjunction with a software acceptance test procedure, which addresses testing of software and electrical features not addressed in this document. Hardware testing will be performed at the 306E Facility in the 300 Area and the Fuels and Materials Examination Facility in the 400 Area. These systems were developed primarily in support of Tank Waste Remediation System (TWRS) Safety Programs for moisture measurement in organic and ferrocyanide watch list tanks

  7. Acetone n-radical cation internal rotation spectrum: The torsional potential surface

    International Nuclear Information System (INIS)

    Shea, Dana A.; Goodman, Lionel; White, Michael G.

    2000-01-01

    The one color REMPI and two color ZEKE-PFI spectra of acetone-d 3 have been recorded. The 3p x Rydberg state of acetone-d 3 lies at 59 362.3 cm-1 and both of the torsional modes are visible in this spectrum. The antigearing Rydberg (a 2 ) mode, v 12 * , has a frequency of 62.5 cm-1, while the previously unobserved gearing (b 1 ) mode, v 17 * , is found at 119.1 cm-1. An ionization potential of 78 299.6 cm-1 for acetone-d 3 has been measured. In acetone-d 3 n-radical cation ground state, the fundamentals of both of the torsional modes have been observed, v 12 + at 51.0 cm-1 and v 17 + at 110.4 cm-1, while the first overtone of v 12 + has been measured at 122.4 cm-1. Deuterium shifts show that v 12 + behaves like a local C 3v rotor, but that v 17 + is canonical. Combining this data with that for acetone-d 0 and aacetone-d 6 has allowed us to fit the observed frequencies to a torsional potential energy surface based on an ab initio C 2v cation ground state geometry. This potential energy surface allows for prediction of the v 17 vibration in acetone-d 0 and acetone-d 6 . The barrier to synchronous rotation is higher in the cation ground state than in the neutral ground state, but significantly lower than in the 3s Rydberg state. The 3p x Rydberg and cation ground state potential energy surfaces are found to be very similar to each other, strongly supporting the contention that the 3p x Rydberg state has C 2v geometry and is a good model for the ion core. The altered 3s Rydberg state potential surface suggests this state has significant valence character. (c) 2000 American Institute of Physics

  8. Detection of microbial contaminations in drinking water using ATP measurements – evaluating potential for online monitoring

    DEFF Research Database (Denmark)

    Vang, Óluva Karin; Corfitzen, Charlotte B.; Albrechtsen, Hans-Jørgen

    2011-01-01

    There is an increasing call for fast and reliable methods for continuous monitoring of microbial drinking water quality in order to protect public health. The potential for Adenosine triphosphate (ATP) measurements as a real-time analysis for continuous monitoring of microbial drinking water...... quality was investigated through simulation of two contamination scenarios, i.e. drinking water contaminated with waste water and surface water at various concentrations. With ATP measurements it was possible to detect waste water diluted 1000-10,000 times in drinking water depending on sensitivity...... of reagent kit. Surface water diluted 100-1000 times was detected in drinking water with ATP measurements. ATP has the potential as an early warning tool, especially in the period when the contamination concentration is high. 2011 © American Water Works Association AWWA WQTC Conference Proceedings All Rights...

  9. Dynamic potential and surface morphology study of sertraline membrane sensors

    Science.gov (United States)

    Khater, M.M.; Issa, Y.M.; Hassib, H.B.; Mohammed, S.H.

    2014-01-01

    New rapid, sensitive and simple electrometric method was developed to determine sertraline hydrochloride (Ser-Cl) in its pure raw material and pharmaceutical formulations. Membrane sensors based on heteropolyacids as ion associating material were prepared. Silicomolybdic acid (SMA), silicotungstic acid (STA) and phosphomolybdic acid (PMA) were used. The slope and limit of detection are 50.00, 60.00 and 53.24 mV/decade and 2.51, 5.62 and 4.85 μmol L−1 for Ser-ST, Ser-PM and Ser-SM membrane sensors, respectively. Linear range is 0.01–10.00 for the three sensors. These new sensors were used for the potentiometric titration of Ser-Cl using sodium tetraphenylborate as titrant. The surface morphologies of the prepared membranes with and without the modifier (ion-associate) were studied using scanning and atomic force microscopes. PMID:26257944

  10. Reliability of surface EMG measurements from the suprahyoid muscle complex

    DEFF Research Database (Denmark)

    Kothari, Mohit; Stubbs, Peter William; Pedersen, Asger Roer

    2017-01-01

    of using the suprahyoid muscle complex (SMC) using surface electromyography (sEMG) to assess changes to neural pathways by determining the reliability of measurements in healthy participants over days. Methods: Seventeen healthy participants were recruited. Measurements were performed twice with one week...... on stimulus type/intensity) had significantly different MEP values between day 1 and day 2 for single pulse and paired pulse TMS. A large stimulus artefact resulted in MEP responses that could not be assessed in four participants. Conclusions: The assessment of the SMC using sEMG following TMS was poorly...... reliable for ≈50% of participants. Although using sEMG to assess swallowing musculature function is easier to perform clinically and more comfortable to patients than invasive measures, as the measurement of muscle activity using TMS is unreliable, the use of sEMG for this muscle group is not recommended...

  11. Photometric imaging in particle size measurement and surface visualization.

    Science.gov (United States)

    Sandler, Niklas

    2011-09-30

    The aim of this paper is to give an insight into photometric particle sizing approaches, which differ from the typical particle size measurement of dispersed particles. These approaches can often be advantageous especially for samples that are moist or cohesive, when dispersion of particles is difficult or sometimes impossible. The main focus of this paper is in the use of photometric stereo imaging. The technique allows the reconstruction of three-dimensional images of objects using multiple light sources in illumination. The use of photometric techniques is demonstrated in at-line measurement of granules and on-line measurement during granulation and dry milling. Also, surface visualization and roughness measurements are briefly discussed. Copyright © 2010 Elsevier B.V. All rights reserved.

  12. Electrohydrodynamics of binary electrolytes driven by modulated surface potentials

    DEFF Research Database (Denmark)

    Mortensen, Asger; Olesen, Laurits Højgaard; Belmon, L.

    2005-01-01

    We study the electrohydrodynamics of the Debye screening layer that arises in an aqueous binary solution near a planar insulating wall when applying a spatially modulated ac voltage. Combining this with first order perturbation theory we establish the governing equations for the full nonequilibrium...... problem and obtain analytic solutions in the bulk for the pressure and velocity fields of the electrolyte and for the electric potential. We find good agreement between the numerics of the full problem and the analytics of the linear theory. Our work provides the theoretical foundations of circuit models...

  13. Oxathiiranes 8 On the OCS2 Singlet Potential Energy Surface

    DEFF Research Database (Denmark)

    Carlsen, Lars

    1982-01-01

    The reaction between atomic oxygen and carbon disulfide is predicted to lead to at least two primary products, which are the dithiiranone (1) and the oxathiirane-thione (2) and/or the carbon disulfide S-oxide (4). The possible intramolecular equilibria 1 ⇄ 2, 1 ⇄ 3, 2 ⇄ 4, and 2 ⇄ 5 as well...... as the fragmentations of the possible intermediates 1–5 have been studied theoretically within the semiempirical cndo/B framework as conceivable ground-state reactions. On the basis of mo correlations and potential energy changes along the reaction paths, supplementary with previously reported experimental data...

  14. Commencement measurements giving fundamental surface tension determinations in tensiometry

    International Nuclear Information System (INIS)

    Carbery, D; Morrin, D; O'Rourke, B; McMillan, N D; O'Neill, M; Riedel, S; Pringuet, P; Smith, S R P

    2011-01-01

    This study provides experimental testing of a ray-tracing model of the tensiotrace that explores the measurement potential of a well-defined optical position in the tensiotrace signal known as the 'commencement'. This point is defined as the first measureable optical coupling in the fiber drophead between source and collector fibers for light injected inside a growing drop. Tensiotrace ray-tracing model is briefly introduced. Empirical relationships of commencement measures from a wide-ranging study are presented. A number of conclusions can be drawn from the successful linking of computer predictions to these experimental relationships.

  15. Measuring the inward FDI potential of South African regions

    Directory of Open Access Journals (Sweden)

    W. Krugell

    2008-12-01

    Full Text Available Purpose: The purpose of this paper is to construct an index that captures the factors expected to affect a local economy's attractiveness to foreign investors. Problem statement: Following South Africa's reintegration into the world economy in 1994, foreign direct investment has been seen as a potential driver of growth and development. Concerns about the low investment rate in South Africa raise the possibility of augmenting domestic with foreign investment expenditure. The potential of technology spillovers and skills transfer from foreign direct investment have also been emphasised. As a result, Trade and Investment South Africa is involved in identifying, packaging and promoting investment opportunities. However, investments tend to be place-specific and this has lead to the decentralisation of foreign direct investment promotion. Currently the nine provincial development agencies are competing to attract investors and the larger local governments are also getting involved in the fray. This paper argues that some places have better potential to attract foreign investment than others. A first step to use scarce investment promotion resources more efficiently would be to measure the inward FDI potential of South African regions. Approach: This paper uses principal components analysis to construct an index that captures the factors expected to affect a local economy's attractiveness to foreign investors. This approach draws on UNCTAD's Inward FDI Potential Index and applies it to 354 magisterial districts in South Africa for the periods 1996, 2001 and 2006. The index creates a summary measure of FDI potential. Findings: The results show that different places present differential potential in urbanization and localization economies and market size. The high-potential locations are typically found in or around the major agglomerations, but there are a few smaller places on the periphery that offer FDI potential. Contribution: The index should aid

  16. An induced current method for measuring zeta potential of electrolyte solution-air interface.

    Science.gov (United States)

    Song, Yongxin; Zhao, Kai; Wang, Junsheng; Wu, Xudong; Pan, Xinxiang; Sun, Yeqing; Li, Dongqing

    2014-02-15

    This paper reports a novel and very simple method for measuring the zeta potential of electrolyte solution-air interface. When a measuring electrode contacts the electrolyte solution-air interface, an electrical current will be generated due to the potential difference between the electrode-air surface and the electrolyte solution-air interface. The amplitude of the measured electric signal is linearly proportional to this potential difference; and depends only on the zeta potential at the electrolyte solution-air interface, regardless of the types and concentrations of the electrolyte. A correlation between the zeta potential and the measured voltage signal is obtained based on the experimental data. Using this equation, the zeta potential of any electrolyte solution-air interface can be evaluated quickly and easily by inserting an electrode through the electrolyte solution-air interface and measuring the electrical signal amplitude. This method was verified by comparing the obtained results of NaCl, MgCl2 and CaCl2 solutions of different pH values and concentrations with the zeta potential data reported in the published journal papers. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Measurement of event-related potentials and placebo

    Directory of Open Access Journals (Sweden)

    Sovilj Platon

    2014-01-01

    Full Text Available ERP is common abbreviation for event-related brain potentials, which are measured and used in clinical practice as well as in research practice. Contemporary studies of placebo effect are often based on functional neuromagnetic resonance (fMRI, positron emission tomography (PET, and event related potentials (ERP. This paper considers an ERP instrumentation system used in experimental researches of placebo effect. This instrumentation system can be divided into four modules: electrodes and cables, conditioning module, digital measurement module, and PC module for stimulations, presentations, acquisition and data processing. The experimental oddball paradigm is supported by the software of the instrumentation. [Projekat Ministarstva nauke Republike Srbije, br. TR32019 and Provincial Secretariat for Science and Technological Development of Autonomous Province of Vojvodina (Republic of Serbia under research grant No. 114-451-2723

  18. Potential effects of groundwater and surface water contamination in an urban area, Qus City, Upper Egypt

    Science.gov (United States)

    Abdalla, Fathy; Khalil, Ramadan

    2018-05-01

    The potential effects of anthropogenic activities, in particular, unsafe sewage disposal practices, on shallow groundwater in an unconfined aquifer and on surface water were evaluated within an urban area by the use of hydrogeological, hydrochemical, and bacteriological analyses. Physicochemical and bacteriological data was obtained from forty-five sampling points based on33 groundwater samples from variable depths and 12 surface water samples. The pollution sources are related to raw sewage and wastewater discharges, agricultural runoff, and wastewater from the nearby Paper Factory. Out of the 33 groundwater samples studied, 17 had significant concentrations of NO3-, Cl- and SO42-, and high bacteria counts. Most of the water samples from the wells contained high Fe, Mn, Pb, Zn, Cd, and Cr. The majority of surface water samples presented high NO3- concentrations and high bacteria counts. A scatter plot of HCO3- versus Ca indicates that 58% of the surface water samples fall within the extreme contamination zone, while the others are within the mixing zone; whereas 94% of groundwater samples showed evidence of mixing between groundwater and wastewater. The bacteriological assessment showed that all measured surface and groundwater samples contained Escherichia coli and total coliform bacteria. A risk map delineated four classes of contamination, namely, those sampling points with high (39.3%), moderate (36.3%), low (13.3%), and very low (11.1%) levels of contamination. Most of the highest pollution points were in the middle part of the urban area, which suffers from unmanaged sewage and industrial effluents. Overall, the results demonstrate that surface and groundwater in Qus City are at high risk of contamination by wastewater since the water table is shallow and there is a lack of a formal sanitation network infrastructure. The product risk map is a useful tool for prioritizing zones that require immediate mitigation and monitoring.

  19. FAIR VALUE MEASUREMENT IN AGRICULTURE AND THE POTENTIAL TO MISLEAD

    Directory of Open Access Journals (Sweden)

    VLADU ALINA BEATTRICE

    2013-08-01

    Full Text Available Applying fair value measurement to tangible and intangible assets in agriculture cannot be risk free. Twofoldreasons can be brought into attention for the above statement: fair value estimation and the specific of agriculturefield. The purpose of this discussion paper is to underline potential creative accounting demarches that can appear inthis context. The paper concludes based on the discussions approached in the literature. Further avenues of researchare discussed.

  20. Classifying Floating Potential Measurement Unit Data Products as Science Data

    Science.gov (United States)

    Coffey, Victoria; Minow, Joseph

    2015-01-01

    We are Co-Investigators for the Floating Potential Measurement Unit (FPMU) on the International Space Station (ISS) and members of the FPMU operations and data analysis team. We are providing this memo for the purpose of classifying raw and processed FPMU data products and ancillary data as NASA science data with unrestricted, public availability in order to best support science uses of the data.

  1. A healthy lifestyle composite measure: Significance and potential uses.

    Science.gov (United States)

    Adams, Mary L; Katz, David L; Shenson, Douglas

    2016-03-01

    Our objective was to create and explore potential uses of a composite "Healthy Lifestyle" measure based on Healthy People 2020 (HP2020) Objectives for behaviors shown to be associated with morbidity and mortality. Data were from the 2013 Behavioral Risk Factor Surveillance System (N=412,942) on five modifiable behaviors with HP2020 Objectives (leisure time exercise, eating fruits and vegetables 5 or more times/day, getting ≥7h of sleep/24h, not smoking and not drinking excessively). These indicators were combined to form an all-or-none composite Healthy Lifestyle (HLS) measure. Associations between the HLS measure and demographic and other measures, plus details of component measures, were reported. Results indicated that only 7.7% of adults reported a HLS with wide variation among states and demographic groups. Both unadjusted and logistic regression results found associations between a HLS and better health, lower rates of chronic disease and better access to health care. Over one fourth of all respondents (28.0%) needed to only improve fruit and vegetable consumption to be practicing a HLS. In conclusion, few adults were practicing five behaviors that are generally recognized as healthy. All-or-none metrics like this HLS measure offer a fresh perspective on modifiable behaviors and the need for improvement. Examination of measure components can help explain demographic differences and identify strategies for improvement. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. 3D Printed Potential and Free Energy Surfaces for Teaching Fundamental Concepts in Physical Chemistry

    Science.gov (United States)

    Kaliakin, Danil S.; Zaari, Ryan R.; Varganov, Sergey A.

    2015-01-01

    Teaching fundamental physical chemistry concepts such as the potential energy surface, transition state, and reaction path is a challenging task. The traditionally used oversimplified 2D representation of potential and free energy surfaces makes this task even more difficult and often confuses students. We show how this 2D representation can be…

  3. Ab Initio and DFT Potential Energy Surfaces for Cyanuric Chloride Reactions

    National Research Council Canada - National Science Library

    Pai, Sharmila

    1998-01-01

    ... on the potential energy surface were calculated using the 6-31G and 6-311 +Gbasis sets. DFT(B3LYP) geometry optimizations and zero-point corrections for critical points on the potential energy surface were calculated with the 6-31G, 6-311...

  4. Hot-electron-mediated desorption rates calculated from excited-state potential energy surfaces

    DEFF Research Database (Denmark)

    Olsen, Thomas; Gavnholt, Jeppe; Schiøtz, Jakob

    2009-01-01

    We present a model for desorption induced by (multiple) electronic transitions [DIET (DIMET)] based on potential energy surfaces calculated with the delta self-consistent field extension of density-functional theory. We calculate potential energy surfaces of CO and NO molecules adsorbed on variou...

  5. Potential environmental effects of energy conservation measures in northwest industries

    Energy Technology Data Exchange (ETDEWEB)

    Baechler, M C; Gygi, K F; Hendrickson, P L

    1992-01-01

    The Bonneville Power Administration (Bonneville) has identified 101 plants in the Pacific Northwest that account for 80% of the region's industrial electricity consumption. These plants offer a precise target for a conservation program. PNL determined that most of these 101 plants were represented by 11 major industries. We then reviewed 36 major conservation technologies used in these 11 industrial settings to determine their potential environmental impacts. Energy efficiency technologies designed for industrial use may result in direct or indirect environmental impacts. Effects may result from the production of the conservation measure technology, changes in the working environment due to different energy and material requirements, or changes to waste streams. Industry type, work-place conditions, worker training, and environmental conditions inside and outside the plant are all key variables that may affect environmental outcomes. To address these issues this report has three objectives: Describe potential conservation measures that Bonneville may employ in industrial programs and discuss potential primary impacts. Characterize industrial systems and processes where the measure may be employed and describe general environmental issues associated with each industry type. Review environmental permitting, licensing, and other regulatory actions required for industries and summarize the type of information available from these sources for further analysis.

  6. Radiotherapy high energy surface dose measurements: effects of chamber polarity

    International Nuclear Information System (INIS)

    Cheung, T.; Yu, P.K.N.; Butson, M.J.; Cancer Services, Wollongong, NSW

    2004-01-01

    Full text: The effects of chamber polarity have been investigated for the measurement of 6MV and 18MV x-ray surface dose using a parallel plate ionization chamber. Results have shown that a significant difference in measured ionization is recorded between to polarities at 6MV and 18MV at the phantom surface. A polarity ratio ranging from 1 062 to 1 005 is seen for 6MV x-rays at the phantom surface for field sizes 5cm x 5cm to 40cm x 40cm when comparing positive to negative polarity. These ratios range from 1.024 to 1.004 for 18MV x-rays with the same field sizes. When these charge reading are compared to the D max readings of the same polarity it is found that these polarity effects are minimal for the calculation of percentage dose results with variations being less than 1% of maximum. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

  7. Surface Current Measurements In Terra Nova Bay By Hf Radar

    Science.gov (United States)

    Flocco, D.; Falco, P.; Wadhams, P.; Spezie, G.

    We present the preliminary results of a field experiment carried out within frame- work of the CLIMA project of the Italian National Programme for Antarctic Research (PNRA) and in cooperation with the Scott Polar Research Institute of Cambridge. Dur- ing the second period (02/12/1999-23/01/2000) of the XV Italian expedition a coastal radar was used to characterize the current field in the area of Terra Nova Bay (TNB). One of the aims of the CLIMA (Climatic Long-term Interactions for the Mass balance in Antarctica) project is to determine the role of the polynya in the sea ice mass bal- ance, water structure and local climate. The OSCR-II experiment was planned in order to provide surface current measurements in the area of TNB polynya, one of the most important coastal polynya of the Ross Sea. OSCR (Ocean Surface Current Radar) is a shore based, remote sensing system designed to measure sea surface currents in coastal waters. Two radar sites (a master and a slave) provide with radial current mea- surements; data combined from both sites yield the total current vector. Unfortunately the master and slave stations did not work together throughout the whole period of the experiment. A description of the experiment and a discussion of the results, will be proposed.

  8. Measuring the potential utility of seasonal climate predictions

    Science.gov (United States)

    Tippett, Michael K.; Kleeman, Richard; Tang, Youmin

    2004-11-01

    Variation of sea surface temperature (SST) on seasonal-to-interannual time-scales leads to changes in seasonal weather statistics and seasonal climate anomalies. Relative entropy, an information theory measure of utility, is used to quantify the impact of SST variations on seasonal precipitation compared to natural variability. An ensemble of general circulation model (GCM) simulations is used to estimate this quantity in three regions where tropical SST has a large impact on precipitation: South Florida, the Nordeste of Brazil and Kenya. We find the yearly variation of relative entropy is strongly correlated with shifts in ensemble mean precipitation and weakly correlated with ensemble variance. Relative entropy is also found to be related to measures of the ability of the GCM to reproduce observations.

  9. Mars' Surface Radiation Environment Measured with the Mars Science Laboratory's Curiosity Rover

    Science.gov (United States)

    Hassler, Donald M.; Zeitlin, Cary; Wimmer-Schweingruber, Robert F.; Ehresmann, Bent; Rafkin, Scot; Eigenbrode, Jennifer L.; Brinza, David E.; Weigle, Gerald; Böttcher, Stephan; Böhm, Eckart; Burmeister, Soenke; Guo, Jingnan; Köhler, Jan; Martin, Cesar; Reitz, Guenther; Cucinotta, Francis A.; Kim, Myung-Hee; Grinspoon, David; Bullock, Mark A.; Posner, Arik; Gómez-Elvira, Javier; Vasavada, Ashwin; Grotzinger, John P.; MSL Science Team; Kemppinen, Osku; Cremers, David; Bell, James F.; Edgar, Lauren; Farmer, Jack; Godber, Austin; Wadhwa, Meenakshi; Wellington, Danika; McEwan, Ian; Newman, Claire; Richardson, Mark; Charpentier, Antoine; Peret, Laurent; King, Penelope; Blank, Jennifer; Schmidt, Mariek; Li, Shuai; Milliken, Ralph; Robertson, Kevin; Sun, Vivian; Baker, Michael; Edwards, Christopher; Ehlmann, Bethany; Farley, Kenneth; Griffes, Jennifer; Miller, Hayden; Newcombe, Megan; Pilorget, Cedric; Rice, Melissa; Siebach, Kirsten; Stack, Katie; Stolper, Edward; Brunet, Claude; Hipkin, Victoria; Léveillé, Richard; Marchand, Geneviève; Sánchez, Pablo Sobrón; Favot, Laurent; Cody, George; Steele, Andrew; Flückiger, Lorenzo; Lees, David; Nefian, Ara; Martin, Mildred; Gailhanou, Marc; Westall, Frances; Israël, Guy; Agard, Christophe; Baroukh, Julien; Donny, Christophe; Gaboriaud, Alain; Guillemot, Philippe; Lafaille, Vivian; Lorigny, Eric; Paillet, Alexis; Pérez, René; Saccoccio, Muriel; Yana, Charles; Armiens-Aparicio, Carlos; Rodríguez, Javier Caride; Blázquez, Isaías Carrasco; Gómez, Felipe Gómez; Hettrich, Sebastian; Malvitte, Alain Lepinette; Jiménez, Mercedes Marín; Martínez-Frías, Jesús; Martín-Soler, Javier; Martín-Torres, F. Javier; Jurado, Antonio Molina; Mora-Sotomayor, Luis; Caro, Guillermo Muñoz; López, Sara Navarro; Peinado-González, Verónica; Pla-García, Jorge; Manfredi, José Antonio Rodriguez; Romeral-Planelló, Julio José; Fuentes, Sara Alejandra Sans; Martinez, Eduardo Sebastian; Redondo, Josefina Torres; Urqui-O'Callaghan, Roser; Mier, María-Paz Zorzano; Chipera, Steve; Lacour, Jean-Luc; Mauchien, Patrick; Sirven, Jean-Baptiste; Manning, Heidi; Fairén, Alberto; Hayes, Alexander; Joseph, Jonathan; Squyres, Steven; Sullivan, Robert; Thomas, Peter; Dupont, Audrey; Lundberg, Angela; Melikechi, Noureddine; Mezzacappa, Alissa; Berger, Thomas; Matthia, Daniel; Prats, Benito; Atlaskin, Evgeny; Genzer, Maria; Harri, Ari-Matti; Haukka, Harri; Kahanpää, Henrik; Kauhanen, Janne; Kemppinen, Osku; Paton, Mark; Polkko, Jouni; Schmidt, Walter; Siili, Tero; Fabre, Cécile; Wray, James; Wilhelm, Mary Beth; Poitrasson, Franck; Patel, Kiran; Gorevan, Stephen; Indyk, Stephen; Paulsen, Gale; Gupta, Sanjeev; Bish, David; Schieber, Juergen; Gondet, Brigitte; Langevin, Yves; Geffroy, Claude; Baratoux, David; Berger, Gilles; Cros, Alain; d'Uston, Claude; Forni, Olivier; Gasnault, Olivier; Lasue, Jérémie; Lee, Qiu-Mei; Maurice, Sylvestre; Meslin, Pierre-Yves; Pallier, Etienne; Parot, Yann; Pinet, Patrick; Schröder, Susanne; Toplis, Mike; Lewin, Éric; Brunner, Will; Heydari, Ezat; Achilles, Cherie; Oehler, Dorothy; Sutter, Brad; Cabane, Michel; Coscia, David; Israël, Guy; Szopa, Cyril; Dromart, Gilles; Robert, François; Sautter, Violaine; Le Mouélic, Stéphane; Mangold, Nicolas; Nachon, Marion; Buch, Arnaud; Stalport, Fabien; Coll, Patrice; François, Pascaline; Raulin, François; Teinturier, Samuel; Cameron, James; Clegg, Sam; Cousin, Agnès; DeLapp, Dorothea; Dingler, Robert; Jackson, Ryan Steele; Johnstone, Stephen; Lanza, Nina; Little, Cynthia; Nelson, Tony; Wiens, Roger C.; Williams, Richard B.; Jones, Andrea; Kirkland, Laurel; Treiman, Allan; Baker, Burt; Cantor, Bruce; Caplinger, Michael; Davis, Scott; Duston, Brian; Edgett, Kenneth; Fay, Donald; Hardgrove, Craig; Harker, David; Herrera, Paul; Jensen, Elsa; Kennedy, Megan R.; Krezoski, Gillian; Krysak, Daniel; Lipkaman, Leslie; Malin, Michael; McCartney, Elaina; McNair, Sean; Nixon, Brian; Posiolova, Liliya; Ravine, Michael; Salamon, Andrew; Saper, Lee; Stoiber, Kevin; Supulver, Kimberley; Van Beek, Jason; Van Beek, Tessa; Zimdar, Robert; French, Katherine Louise; Iagnemma, Karl; Miller, Kristen; Summons, Roger; Goesmann, Fred; Goetz, Walter; Hviid, Stubbe; Johnson, Micah; Lefavor, Matthew; Lyness, Eric; Breves, Elly; Dyar, M. Darby; Fassett, Caleb; Blake, David F.; Bristow, Thomas; DesMarais, David; Edwards, Laurence; Haberle, Robert; Hoehler, Tori; Hollingsworth, Jeff; Kahre, Melinda; Keely, Leslie; McKay, Christopher; Wilhelm, Mary Beth; Bleacher, Lora; Brinckerhoff, William; Choi, David; Conrad, Pamela; Dworkin, Jason P.; Floyd, Melissa; Freissinet, Caroline; Garvin, James; Glavin, Daniel; Harpold, Daniel; Jones, Andrea; Mahaffy, Paul; Martin, David K.; McAdam, Amy; Pavlov, Alexander; Raaen, Eric; Smith, Michael D.; Stern, Jennifer; Tan, Florence; Trainer, Melissa; Meyer, Michael; Voytek, Mary; Anderson, Robert C.; Aubrey, Andrew; Beegle, Luther W.; Behar, Alberto; Blaney, Diana; Calef, Fred; Christensen, Lance; Crisp, Joy A.; DeFlores, Lauren; Ehlmann, Bethany; Feldman, Jason; Feldman, Sabrina; Flesch, Gregory; Hurowitz, Joel; Jun, Insoo; Keymeulen, Didier; Maki, Justin; Mischna, Michael; Morookian, John Michael; Parker, Timothy; Pavri, Betina; Schoppers, Marcel; Sengstacken, Aaron; Simmonds, John J.; Spanovich, Nicole; Juarez, Manuel de la Torre; Webster, Christopher R.; Yen, Albert; Archer, Paul Douglas; Jones, John H.; Ming, Douglas; Morris, Richard V.; Niles, Paul; Rampe, Elizabeth; Nolan, Thomas; Fisk, Martin; Radziemski, Leon; Barraclough, Bruce; Bender, Steve; Berman, Daniel; Dobrea, Eldar Noe; Tokar, Robert; Vaniman, David; Williams, Rebecca M. E.; Yingst, Aileen; Lewis, Kevin; Leshin, Laurie; Cleghorn, Timothy; Huntress, Wesley; Manhès, Gérard; Hudgins, Judy; Olson, Timothy; Stewart, Noel; Sarrazin, Philippe; Grant, John; Vicenzi, Edward; Wilson, Sharon A.; Hamilton, Victoria; Peterson, Joseph; Fedosov, Fedor; Golovin, Dmitry; Karpushkina, Natalya; Kozyrev, Alexander; Litvak, Maxim; Malakhov, Alexey; Mitrofanov, Igor; Mokrousov, Maxim; Nikiforov, Sergey; Prokhorov, Vasily; Sanin, Anton; Tretyakov, Vladislav; Varenikov, Alexey; Vostrukhin, Andrey; Kuzmin, Ruslan; Clark, Benton; Wolff, Michael; McLennan, Scott; Botta, Oliver; Drake, Darrell; Bean, Keri; Lemmon, Mark; Schwenzer, Susanne P.; Anderson, Ryan B.; Herkenhoff, Kenneth; Lee, Ella Mae; Sucharski, Robert; Hernández, Miguel Ángel de Pablo; Ávalos, Juan José Blanco; Ramos, Miguel; Malespin, Charles; Plante, Ianik; Muller, Jan-Peter; Navarro-González, Rafael; Ewing, Ryan; Boynton, William; Downs, Robert; Fitzgibbon, Mike; Harshman, Karl; Morrison, Shaunna; Dietrich, William; Kortmann, Onno; Palucis, Marisa; Sumner, Dawn Y.; Williams, Amy; Lugmair, Günter; Wilson, Michael A.; Rubin, David; Jakosky, Bruce; Balic-Zunic, Tonci; Frydenvang, Jens; Jensen, Jaqueline Kløvgaard; Kinch, Kjartan; Koefoed, Asmus; Madsen, Morten Bo; Stipp, Susan Louise Svane; Boyd, Nick; Campbell, John L.; Gellert, Ralf; Perrett, Glynis; Pradler, Irina; VanBommel, Scott; Jacob, Samantha; Owen, Tobias; Rowland, Scott; Atlaskin, Evgeny; Savijärvi, Hannu; García, César Martín; Mueller-Mellin, Reinhold; Bridges, John C.; McConnochie, Timothy; Benna, Mehdi; Franz, Heather; Bower, Hannah; Brunner, Anna; Blau, Hannah; Boucher, Thomas; Carmosino, Marco; Atreya, Sushil; Elliott, Harvey; Halleaux, Douglas; Rennó, Nilton; Wong, Michael; Pepin, Robert; Elliott, Beverley; Spray, John; Thompson, Lucy; Gordon, Suzanne; Newsom, Horton; Ollila, Ann; Williams, Joshua; Vasconcelos, Paulo; Bentz, Jennifer; Nealson, Kenneth; Popa, Radu; Kah, Linda C.; Moersch, Jeffrey; Tate, Christopher; Day, Mackenzie; Kocurek, Gary; Hallet, Bernard; Sletten, Ronald; Francis, Raymond; McCullough, Emily; Cloutis, Ed; ten Kate, Inge Loes; Kuzmin, Ruslan; Arvidson, Raymond; Fraeman, Abigail; Scholes, Daniel; Slavney, Susan; Stein, Thomas; Ward, Jennifer; Berger, Jeffrey; Moores, John E.

    2014-01-01

    The Radiation Assessment Detector (RAD) on the Mars Science Laboratory's Curiosity rover began making detailed measurements of the cosmic ray and energetic particle radiation environment on the surface of Mars on 7 August 2012. We report and discuss measurements of the absorbed dose and dose equivalent from galactic cosmic rays and solar energetic particles on the martian surface for ~300 days of observations during the current solar maximum. These measurements provide insight into the radiation hazards associated with a human mission to the surface of Mars and provide an anchor point with which to model the subsurface radiation environment, with implications for microbial survival times of any possible extant or past life, as well as for the preservation of potential organic biosignatures of the ancient martian environment.

  10. Mars' surface radiation environment measured with the Mars Science Laboratory's Curiosity rover.

    Science.gov (United States)

    Hassler, Donald M; Zeitlin, Cary; Wimmer-Schweingruber, Robert F; Ehresmann, Bent; Rafkin, Scot; Eigenbrode, Jennifer L; Brinza, David E; Weigle, Gerald; Böttcher, Stephan; Böhm, Eckart; Burmeister, Soenke; Guo, Jingnan; Köhler, Jan; Martin, Cesar; Reitz, Guenther; Cucinotta, Francis A; Kim, Myung-Hee; Grinspoon, David; Bullock, Mark A; Posner, Arik; Gómez-Elvira, Javier; Vasavada, Ashwin; Grotzinger, John P

    2014-01-24

    The Radiation Assessment Detector (RAD) on the Mars Science Laboratory's Curiosity rover began making detailed measurements of the cosmic ray and energetic particle radiation environment on the surface of Mars on 7 August 2012. We report and discuss measurements of the absorbed dose and dose equivalent from galactic cosmic rays and solar energetic particles on the martian surface for ~300 days of observations during the current solar maximum. These measurements provide insight into the radiation hazards associated with a human mission to the surface of Mars and provide an anchor point with which to model the subsurface radiation environment, with implications for microbial survival times of any possible extant or past life, as well as for the preservation of potential organic biosignatures of the ancient martian environment.

  11. Estimating regional methane surface fluxes: the relative importance of surface and GOSAT mole fraction measurements

    Directory of Open Access Journals (Sweden)

    A. Fraser

    2013-06-01

    Full Text Available We use an ensemble Kalman filter (EnKF, together with the GEOS-Chem chemistry transport model, to estimate regional monthly methane (CH4 fluxes for the period June 2009–December 2010 using proxy dry-air column-averaged mole fractions of methane (XCH4 from GOSAT (Greenhouse gases Observing SATellite and/or NOAA ESRL (Earth System Research Laboratory and CSIRO GASLAB (Global Atmospheric Sampling Laboratory CH4 surface mole fraction measurements. Global posterior estimates using GOSAT and/or surface measurements are between 510–516 Tg yr−1, which is less than, though within the uncertainty of, the prior global flux of 529 ± 25 Tg yr−1. We find larger differences between regional prior and posterior fluxes, with the largest changes in monthly emissions (75 Tg yr−1 occurring in Temperate Eurasia. In non-boreal regions the error reductions for inversions using the GOSAT data are at least three times larger (up to 45% than if only surface data are assimilated, a reflection of the greater spatial coverage of GOSAT, with the two exceptions of latitudes >60° associated with a data filter and over Europe where the surface network adequately describes fluxes on our model spatial and temporal grid. We use CarbonTracker and GEOS-Chem XCO2 model output to investigate model error on quantifying proxy GOSAT XCH4 (involving model XCO2 and inferring methane flux estimates from surface mole fraction data and show similar resulting fluxes, with differences reflecting initial differences in the proxy value. Using a series of observing system simulation experiments (OSSEs we characterize the posterior flux error introduced by non-uniform atmospheric sampling by GOSAT. We show that clear-sky measurements can theoretically reproduce fluxes within 10% of true values, with the exception of tropical regions where, due to a large seasonal cycle in the number of measurements because of clouds and aerosols, fluxes are within 15% of true fluxes. We evaluate our

  12. Measurement of solar radiation at the Earth's surface

    Science.gov (United States)

    Bartman, F. L.

    1982-01-01

    The characteristics of solar energy arriving at the surface of the Earth are defined and the history of solar measurements in the United States presented. Radiation and meteorological measurements being made at solar energy meteorological research and training sites and calibration procedures used there are outlined. Data illustrating the annual variation in daily solar radiation at Ann Arbor, Michigan and the diurnal variation in radiation at Albuquerque, New Mexico are presented. Direct normal solar radiation received at Albuquerque is contrasted with that received at Maynard, Massachusetts. Average measured global radiation for a period of one year for four locations under clear skies, 50% cloud cover, and 100% cloud cover is given and compared with the solar radiation at the top of the atmosphere. The May distribution of mean daily direct solar radiation and mean daily global solar radiation over the United States is presented. The effects of turbidity on the direct and circumsolar radiation are shown.

  13. Potential surfaces in symmetric heavy-ion reactions

    International Nuclear Information System (INIS)

    Royer, G.; Piller, C.; Mignen, J.; Raffray, Y.

    1989-01-01

    The entrance channel in symmetric heavy-ion reactions is studied in the liquid-drop model approach including the nuclear proximity energy and allowing ellipsoidal deformations of the colliding nuclei. In the whole mass range a sudden transition occurs from oblate to prolate shapes when the proximity forces become important. This strongly affects the effective moment of inertia. The ellipsoidal deformations reduce the fusion barrier width for light systems and lower the potential barrier height for medium and heavy nuclei. The results are in agreement with the empirical effective barrier shift determined by Aguiar et al for the 58 Ni + 58 Ni, 74 Ge + 74 Ge and 80 Se + 80 Se systems. The sub-barrier fusion enhancement in heavy-ion reactions might be explained by the slowness of the process. Below the static fusion barrier, the reaction time is long; allowing some adiabaticity and deformations of the colliding ions. Above the barrier, the reaction is more sudden and the deformation degree of freedom is frozen

  14. Measurements of flux surfaces in the ATF torsatron

    International Nuclear Information System (INIS)

    England, A.C.; Colchin, R.J.; Harris, J.H.; Hillis, D.L.; Jernigan, T.C.; Anderson, F.S.B.

    1989-01-01

    Flux surfaces in the advanced toroidal facility (ATF) torsatron have been measured using electron-beam techniques. The beam was injected toroidally and impinged on a phosphor-coated screen located ∼ 180 degrees from the gun. The gun was mounted on a drive mechanism that enabled the beam to scan the entire cross section of the last closed flux surface in ATF. The screen material was st. steel, coated with ZnO:Zn (P-15 or P-24) phosphor, and the transparency was ∼ 90%. The emitted light was detected with an image-intensified CCD camera that viewed the mesh through a nearby port. The images were displayed directly on a TV monitor and stored on video tape. Frames from the video tape were transferred to a computer, where the image was enhanced and transformed to remove spatial distortions due to the lens and the viewing angle of the camera

  15. Measuring and interpreting X-ray fluorescence from planetary surfaces.

    Science.gov (United States)

    Owens, Alan; Beckhoff, Burkhard; Fraser, George; Kolbe, Michael; Krumrey, Michael; Mantero, Alfonso; Mantler, Michael; Peacock, Anthony; Pia, Maria-Grazia; Pullan, Derek; Schneider, Uwe G; Ulm, Gerhard

    2008-11-15

    As part of a comprehensive study of X-ray emission from planetary surfaces and in particular the planet Mercury, we have measured fluorescent radiation from a number of planetary analog rock samples using monochromatized synchrotron radiation provided by the BESSY II electron storage ring. The experiments were carried out using a purpose built X-ray fluorescence (XRF) spectrometer chamber developed by the Physikalisch-Technische Bundesanstalt, Germany's national metrology institute. The XRF instrumentation is absolutely calibrated and allows for reference-free quantitation of rock sample composition, taking into account secondary photon- and electron-induced enhancement effects. The fluorescence data, in turn, have been used to validate a planetary fluorescence simulation tool based on the GEANT4 transport code. This simulation can be used as a mission analysis tool to predict the time-dependent orbital XRF spectral distributions from planetary surfaces throughout the mapping phase.

  16. BOREAS RSS-20 POLDER C-130 Measurements of Surface BRDF

    Science.gov (United States)

    Leroy, Marc; Hall, Forrest G. (Editor); Nickerson, Jaime (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    This Boreal Ecosystem-Atmosphere Study (BOREAS) Remote Sensing Science (RSS)-20 data set contains measurements of surface bidirectional reflectance distribution function (BRDF) made by the polarization and Directionality of Earth reflectances (POLDER) instrument over several surface types (pine, spruce, fen) of the BOREAS southern study area (SSA) during the 1994 intensive field campaigns (IFCs). Single-point BRDF values were acquired either from the NASA Ames Research Center (ARC) C-130 aircraft or from a NASA Wallops Flight Facility (WFF) helicopter. A related data set collected from the helicopter platform is available as is POLDER imagery acquired from the C-130. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884) or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  17. Rating of roofs’ surfaces regarding their solar potential and suitability for PV systems, based on LiDAR data

    International Nuclear Information System (INIS)

    Lukač, Niko; Žlaus, Danijel; Seme, Sebastijan; Žalik, Borut; Štumberger, Gorazd

    2013-01-01

    Highlights: ► A new method for estimating and rating buildings roofs’ solar potential is presented. ► Considering LiDAR geospatial data together with pyranometer measurements. ► Use of multi-resolution shadowing model with new heuristic vegetation shadowing. ► High correlation between estimated solar potential and onsite measurements. -- Abstract: The roof surfaces within urban areas are constantly attracting interest regarding the installation of photovoltaic systems. These systems can improve self-sufficiency of electricity supply, and can help to decrease the emissions of greenhouse gases throughout urban areas. Unfortunately, some roof surfaces are unsuitable for installing photovoltaic systems. This presented work deals with the rating of roof surfaces within urban areas regarding their solar potential and suitability for the installation of photovoltaic systems. The solar potential of a roof’s surface is determined by a new method that combines extracted urban topography from LiDAR data with the pyranometer measurements of global and diffuse solar irradiances. Heuristic annual vegetation shadowing and a multi-resolution shadowing model, complete the proposed method. The significance of different influential factors (e.g. shadowing) was analysed extensively. A comparison between the results obtained by the proposed method and measurements performed on an actual PV power plant showed a correlation agreement of 97.4%.

  18. Characterization of the thrombogenic potential of surface oxides on stainless steel for implant purposes

    International Nuclear Information System (INIS)

    Shih, C.-C.; Shih, C.-M.; Su, Y.-Y.; Chang, M.-S.; Lin, S.-J.

    2003-01-01

    Marketed stents are manufactured from various metals and passivated with different degrees of surface oxidation. The functional surface oxides on the degree of antithrombotic potential were explored through a canine femoral extracorporeal circuit model. Related properties of these oxide films were studied by open-circuit potential, current density detected at open-circuit potential, the electrochemical impedance spectroscopy, transmission electron microscopy, Auger spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy. Experimental evidences showed that blood clot weight after a 30-min follow-up was significantly lower for the stainless steel wire passivated with amorphous oxide (AO) compared to the wire passivated with polycrystalline oxide (PO) or commercial as-received wire coils (AS). Surface characterizations showed that a stable negative current density at open-circuit potential and a significant lower potential were found for the wire surface passivated with AO than for the surface passivated with PO. Time constant of AO is about 25 times larger than that of polycrystalline oxide. Significant difference in oxide grain sizes was found between PO and AO. Surface chemistries revealed by the AES and XPS spectra indicated the presence of a Cr- and oxygen-rich surface oxide for AO, and a Fe-rich and oxygen-lean surface oxide for PO. These remarkable characteristics of AO surface film might have a potential to provide for excellent antithrombotic characteristics for the 316L stainless steel stents

  19. Electrical properties of Titan's surface from Cassini RADAR scatterometer measurements

    Science.gov (United States)

    Wye, Lauren C.; Zebker, Howard A.; Ostro, Steven J.; West, Richard D.; Gim, Yonggyu; Lorenz, Ralph D.; The Cassini Radar Team

    2007-06-01

    albedo feature Shangri-La is best fit by a Hagfors model with a dielectric constant close to 2.4 and an rms slope near 9.5°. From the modeled backscatter curves, we find the average radar albedo in the same linear (SL) polarization to be near 0.34. We constrain the total-power albedo in order to compare the measurements with available groundbased radar results, which are typically obtained in both senses of circular polarization. We estimate an upper limit of 0.4 on the total-power albedo, a value that is significantly higher than the 0.21 total albedo value measured at 13 cm [Campbell, D., Black, G., Carter, L., Ostro, S., 2003. Science 302, 431-434]. This is consistent with a surface that has more small-scale structure and is thus more reflective at 2-cm than 13-cm. We compare results across overlapping observations and observe that the reduction and analysis are repeatable and consistent. We also confirm the strong correlations between radar and near-infrared images.

  20. Electrochemical corrosion potential and noise measurement in high temperature water

    International Nuclear Information System (INIS)

    Fong, Clinton; Chen, Yaw-Ming; Chu, Fang; Huang, Chia-Shen

    2000-01-01

    Hydrogen water chemistry (HWC) is one of the most important methods in boiling water reactor(BWR) system to mitigate and prevent stress corrosion cracking (SCC) problems of stainless steel components. Currently, the effectiveness of HWC in each BWR is mainly evaluated by the measurement of electrochemical corrosion potentials (ECP) and on-line monitoring of SCC behaviors of stainless steels. The objective of this work was to evaluate the characteristics and performance of commercially available high temperature reference electrodes. In addition, SCC monitoring technique based on electrochemical noise analysis (ECN) was also tested to examine its crack detection capability. The experimental work on electrochemical corrosion potential (ECP) measurements reveals that high temperature external Ag/AgCl reference electrode of highly dilute KCl electrolyte can adequately function in both NWC and HWC environments. The high dilution external Ag/AgCl electrode can work in conjunction with internal Ag/AgCl reference electrode, and Pt electrode to ensure the ECP measurement reliability. In simulated BWR environment, the electrochemical noise tests of SCC were carried out with both actively and passively loaded specimens of type 304 stainless steel with various electrode arrangements. From the coupling current and corrosion potential behaviors of the passive loading tests during immersion test, it is difficult to interpret the general state of stress corrosion cracking based on the analytical results of overall current and potential variations, local pulse patterns, statistical characteristics, or power spectral density of electrochemical noise signals. However, more positive SCC indication was observed in the power spectral density analysis. For aqueous environments of high solution impedance, successful application of electrochemical noise technique for SCC monitoring may require further improvement in specimen designs and analytical methods to enhance detection sensitivity

  1. Interatomic potentials from rainbow scattering of keV noble gas atoms under axial surface channeling

    International Nuclear Information System (INIS)

    Schueller, A.; Wethekam, S.; Mertens, A.; Maass, K.; Winter, H.; Gaertner, K.

    2005-01-01

    For grazing scattering of keV Ne and Ar atoms from a Ag(1 1 1) and a Cu(1 1 1) surface under axial surface channeling conditions we observe well defined peaks in the angular distributions for scattered projectiles. These peaks can be attributed to 'rainbow-scattering' and are closely related to the geometry of potential energy surfaces which can be approximated by the superposition of continuum potentials along strings of atoms in the surface plane. The dependence of rainbow angles on the scattering geometry provides stringent tests on the scattering potentials. From classical trajectory calculations based on universal (ZBL), adjusted Moliere (O'Connor and Biersack), and individual interatomic potentials we obtain corresponding rainbow angles for comparison with the experimental data. We find good overall agreement with the experiments for a description of trajectories based on adjusted Moliere and individual potentials, whereas the agreement is poorer for potentials with ZBL screening

  2. Design parameters for measurements of local catalytic activity on surfaces

    DEFF Research Database (Denmark)

    Johansson, Martin; Johannessen, Tue; Jørgensen, Jan Hoffmann

    2006-01-01

    Computational fluid dynamics in combination with experiments is used to characterize a gas sampling device for measurements of the local catalytic activity on surfaces. The device basically consists of a quartz capillary mounted concentrically inside an aluminum tube. Reactant gas is blown toward......, the limits of the range in reaction rate, which can be Studied are estimated. (c) 2005 Elsevier B.V. All rights reserved.......Computational fluid dynamics in combination with experiments is used to characterize a gas sampling device for measurements of the local catalytic activity on surfaces. The device basically consists of a quartz capillary mounted concentrically inside an aluminum tube. Reactant gas is blown toward...... limit for the lateral resolution of the measurement, and that a flow rate of the order of 240 (ml/min)(n) is sufficient to achieve this resolution. The sensitivity is reasonable also with high flow rates, due to the presence of a pocket of stagnant gas under the tip of the capillary. Furthermore...

  3. Surface Fitting for Quasi Scattered Data from Coordinate Measuring Systems.

    Science.gov (United States)

    Mao, Qing; Liu, Shugui; Wang, Sen; Ma, Xinhui

    2018-01-13

    Non-uniform rational B-spline (NURBS) surface fitting from data points is wildly used in the fields of computer aided design (CAD), medical imaging, cultural relic representation and object-shape detection. Usually, the measured data acquired from coordinate measuring systems is neither gridded nor completely scattered. The distribution of this kind of data is scattered in physical space, but the data points are stored in a way consistent with the order of measurement, so it is named quasi scattered data in this paper. Therefore they can be organized into rows easily but the number of points in each row is random. In order to overcome the difficulty of surface fitting from this kind of data, a new method based on resampling is proposed. It consists of three major steps: (1) NURBS curve fitting for each row, (2) resampling on the fitted curve and (3) surface fitting from the resampled data. Iterative projection optimization scheme is applied in the first and third step to yield advisable parameterization and reduce the time cost of projection. A resampling approach based on parameters, local peaks and contour curvature is proposed to overcome the problems of nodes redundancy and high time consumption in the fitting of this kind of scattered data. Numerical experiments are conducted with both simulation and practical data, and the results show that the proposed method is fast, effective and robust. What's more, by analyzing the fitting results acquired form data with different degrees of scatterness it can be demonstrated that the error introduced by resampling is negligible and therefore it is feasible.

  4. The Measurement and Interpretation of Surface Wave Group Arrival Times

    Science.gov (United States)

    Masters, G.; Kane, D.; Morrow, J.; Zhou, Y.; Tromp, J.

    2005-12-01

    We have recently developed an efficient technique for measuring the relative group arrival times of surface waves by using cross-correlation and cluster analysis of waveform envelope functions. Applying the analysis to minor arc Love and Rayleigh waves in the frequency band 7 to 35 mHz for all events over magnitude 5.5 results in a dataset of over 200,000 measurements at each frequency for long period Rayleigh waves (frequency less than 25 mHz) and about 100,000 measurements at the shorter periods. Analysis of transverse components results in about half as many Love wave measurements. Simple ray theory inversions of the relative arrival times for apparent group velocity produce maps which are accurate representations of the data (often over 90% variance reduction of the relative arrival times) and which show features strongly correlated with tectonics and crustal thickness. The apparent group velocity variations can be extremely large: 30% velocity variations for 20 mHz Rayleigh waves and 40% variations for 30 mHz Rayleigh waves and can have abrupt lateral changes. This raises the concern that non-ray theory effects could be important. Indeed, a recent analysis by Dahlen and Zhou (personal communication) suggests that the group arrival times should be a functions of both the group velocity AND the phase velocity. The simplest way to test the interpretation of the measurements is to perform the analysis on synthetic seismograms computed for a realistic model of the Earth. Here, we use the SEM with a model which incorporates realistic crust and mantle structure. We are currently computing synthetics for a suite of roughly 1000 events recorded globally that extend to a period of 18 seconds. We shall present the results of applying both ray-based and finite frequency inversions to the synthetic data as well as evaluating the effects of off path propagation at short periods using surface wave ray tracing.

  5. Four-point probe measurements of a direct current potential drop on layered conductive cylinders

    International Nuclear Information System (INIS)

    Lu, Yi; Bowler, John R

    2012-01-01

    We have determined the steady state electric field due to direct current flowing via point contacts at the cylindrical surface of a uniformly layered conductive rod of finite length. The solution allows one to use four-point probe potential drop measurements to estimate the conductivity or thickness of the layer assuming that the other parameters are known. The electrical potential in the rod has a zero radial derivative at its surface except at the injection and extractions points. This means that the required solution can be expressed in terms of a Green’s function satisfying a Neumann boundary condition. Four-point measurements have been made to demonstrate the validity of theoretical results. (paper)

  6. Four-point probe measurements of a direct current potential drop on layered conductive cylinders

    Science.gov (United States)

    Lu, Yi; Bowler, John R.

    2012-11-01

    We have determined the steady state electric field due to direct current flowing via point contacts at the cylindrical surface of a uniformly layered conductive rod of finite length. The solution allows one to use four-point probe potential drop measurements to estimate the conductivity or thickness of the layer assuming that the other parameters are known. The electrical potential in the rod has a zero radial derivative at its surface except at the injection and extractions points. This means that the required solution can be expressed in terms of a Green’s function satisfying a Neumann boundary condition. Four-point measurements have been made to demonstrate the validity of theoretical results.

  7. UNMANNED AIRCRAFT SYSTEMS FOR RAPID NEAR SURFACE GEOPHYSICAL MEASUREMENTS

    Directory of Open Access Journals (Sweden)

    J. B. Stoll

    2013-08-01

    Full Text Available This paper looks at some of the unmanned aircraft systems (UAS options and deals with a magnetometer sensor system which might be of interest in conducting rapid near surface geophysical measurements. Few of the traditional airborne geophysical sensors are now capable of being miniaturized to sizes and payload within mini UAS limits (e.g. airborne magnetics, gamma ray spectrometer. Here the deployment of a fluxgate magnetometer mounted on an UAS is presented demonstrating its capability of detecting metallic materials that are buried in the soil. The effectiveness in finding ferrous objects (e.g. UXO, landslides is demonstrated in two case studies.

  8. Measurement of a surface heat flux and temperature

    Science.gov (United States)

    Davis, R. M.; Antoine, G. J.; Diller, T. E.; Wicks, A. L.

    1994-04-01

    The Heat Flux Microsensor is a new sensor which was recently patented by Virginia Tech and is just starting to be marketed by Vatell Corp. The sensor is made using the thin-film microfabrication techniques directly on the material that is to be measured. It consists of several thin-film layers forming a differential thermopile across a thermal resistance layer. The measured heat flux q is proportional to the temperature difference across the resistance layer q= k(sub g)/delta(sub g) x (t(sub 1) - T(sub 2)), where k(sub g) is the thermal conductivity and delta (sub g) is the thickness of the thermal resistance layer. Because the gages are sputter coated directly onto the surface, their total thickness is less than 2 micrometers, which is two orders of magnitude thinner than previous gages. The resulting temperature difference across the thermal resistance layer (delta is less than 1 micrometer) is very small even at high heat fluxes. To generate a measurable signal many thermocouple pairs are put in series to form a differential thermopile. The combination of series thermocouple junctions and thin-film design creates a gage with very attractive characteristics. It is not only physically non-intrusive to the flow, but also causes minimal disruption of the surface temperature. Because it is so thin, the response time is less than 20 microsec. Consequently, the frequency response is flat from 0 to over 50 kHz. Moreover, the signal of the Heat Flux Microsensor is directly proportional to the heat flux. Therefore, it can easily be used in both steady and transient flows, and it measures both the steady and unsteady components of the surface heat flux. A version of the Heat Flux Microsensor has been developed to meet the harsh demands of combustion environments. These gages use platinum and platinum-10 percent rhodium as the thermoelectric materials. The thermal resistance layer is silicon monoxide and a protective coating of Al2O3 is deposited on top of the sensor. The

  9. Measurement of Streaming Potential in Downhole Application: An Insight for Enhanced Oil Recovery Monitoring

    Directory of Open Access Journals (Sweden)

    Tengku Mohd Tengku Amran

    2017-01-01

    Full Text Available Downhole monitoring using streaming potential measurement has been developing in order to respond to actual reservoir condition. Most studies have emphasized on monitoring water flooding at various reservoir condition and improving the approaches of measurement. Enhanced Oil Recovery (EOR could significantly improve oil recovery and the efficiency of the process should be well-monitored. Alkaline-surfactant-polymer (ASP flooding is the most promising chemical EOR method due to its synergy of alkaline, surfactant and polymer, which could enhance the extraction of residual oil. However, limited studies have been focused on the application of streaming potential in EOR processes, particularly ASP. Thus, this paper aims to review the streaming potential measurement in downhole monitoring with an insight for EOR application and propose the potential measurement in monitoring ASP flooding. It is important for a preliminary study to investigate the synergy in ASP and the effects on oil recovery. The behaviour of streaming potential should be investigated when the environment of porous media changes with respect to ASP flooding. Numerical model can be generated from the experimental data to forecast the measured streaming potential signal during production associated with ASP flooding. Based on the streaming potential behaviour on foam assisted water alternate gas (FAWAG and water alternate gas (WAG processes, it is expected that the streaming potential could change significantly when ASP flooding alters the environment and surface properties of porous media. The findings could provide new prospect and knowledge in the relationship between streaming potential and ASP mechanisms, which could be a potential approach in monitoring the efficiency of the process.

  10. Layer-dependent surface potential of phosphorene and anisotropic/layer-dependent charge transfer in phosphorene-gold hybrid systems.

    Science.gov (United States)

    Xu, Renjing; Yang, Jiong; Zhu, Yi; Yan, Han; Pei, Jiajie; Myint, Ye Win; Zhang, Shuang; Lu, Yuerui

    2016-01-07

    The surface potential and the efficiency of interfacial charge transfer are extremely important for designing future semiconductor devices based on the emerging two-dimensional (2D) phosphorene. Here, we directly measured the strong layer-dependent surface potential of mono- and few-layered phosphorene on gold, which is consistent with the reported theoretical prediction. At the same time, we used an optical way photoluminescence (PL) spectroscopy to probe charge transfer in the phosphorene-gold hybrid system. We firstly observed highly anisotropic and layer-dependent PL quenching in the phosphorene-gold hybrid system, which is attributed to the highly anisotropic/layer-dependent interfacial charge transfer.

  11. Potentially hazardous substances in surface waters. II. Cholinesterase inhibitors in Dutch surface waters

    NARCIS (Netherlands)

    Greve, P.A.; Freudenthal, J.; Wit, S.L.

    1972-01-01

    Several analytical methods were employed to determine the concentrations of cholinesterase inhibitors in several Dutch surface waters. An Auto-Analyzer method was used for screening purposes; thin-layer chromatography and gas-liquid chromatography-mass spectrometry were used for identification and

  12. Contact angle measurements at the colemanite and realgar surfaces

    Science.gov (United States)

    Koca, Sabiha; Savas, Mehmet

    2004-03-01

    Colemanite is one of the most important boron minerals and covers an important part of Turkey's boron mineral deposits. The friable nature of the colemanite tends to produce a large amount of fines. Flotation appears to be a promising technique to recover colemanite from such fines. During flotation process, selectivity problem arises between colemanite and associated gangue minerals such as realgar. There is a close relationship between floatability of minerals and contact angle. Therefore, surface hydrophobicity of colemanite and realgar minerals were investigated by receding contact angle measurements in the absence and presence of flotation reagents. The water contact angle values at the colemanite surface remained almost unchanged at 32-35° in the solutions of potassium amyl xanthate (KAX), potassium ethyl xanthate (KEX) and petroleum sulphanate (R825) while another petroleum sulphanate (R840), sodium oleate and tallow amine (Armac-T) affected hydrophobicity of colemanite, and the contact angle values increased up to 47°. The contact angle values of 62, 63, 45, 46, 39, and 43° at the realgar surface were obtained in the solutions of KAX, KEX, sodium oleate, R825, R840 and Armac-T, respectively.

  13. Measurements of the potential ozone production rate in a forest

    Science.gov (United States)

    Crilley, L.; Sklaveniti, S.; Kramer, L.; Bloss, W.; Flynn, J. H., III; Alvarez, S. L.; Erickson, M.; Dusanter, S.; Locoge, N.; Stevens, P. S.; Millet, D. B.; Alwe, H. D.

    2017-12-01

    Biogenic volatile organic compounds (BVOC) are a significant source of organic compounds globally and alongside NOx play a key role in the formation of ozone in the troposphere. Understanding how changes in NOx concentrations feed through to altered ozone production in BVOC dominated environments will aid our understanding of future atmospheric composition, notably as developing nations transition from NOx dominated to NOx limited chemistry as a result of mitigation strategies. Here we empirically investigate this ambient ozone formation potential. We report deployment of a custom built instrument to measure in near real time the potential for in situ chemical ozone production, using an artificial light source. Our results are thus indicative of the ozone formation potential for a sampled ambient air mixture, including full VOC complexity, i.e. independent of characterization of individual organic compounds. Ground level measurements were performed as part of the PROPHET-AMOS 2016 field campaign, at a site located within a Northern Michigan forest that has typically low NOx abundance, but high isoprene and terpenoid loadings. As the ambient NOx concentrations were low during the campaign, experiments were performed in which NO was artificially added to the sampled ambient air mixture, to quantify changes in the potential ozone production rate as a function of NOx, and hence the ozone forming characteristics of the ambient air. Preliminarily results from these experiments are presented, and indicate that while ozone production increases with added NO, significant variation was observed for a given NO addition, reflecting differences in the ambient VOC chemical reactivity and ozone formation tendency.

  14. Measurement of Tritium Surface Distribution on TFTR Bumper Limiter Tiles

    International Nuclear Information System (INIS)

    Sugiyama, K.; Tanabe, T.; Skinner, C.H.; Gentile, C.A.

    2004-01-01

    The tritium surface distribution on graphite tiles used in the Tokamak Fusion Test Reactor (TFTR) bumper limiter and exposed to TFTR deuterium-tritium (D-T) discharges from 1993 to 1997 was measured by the Tritium Imaging Plate Technique (TIPT). The TFTR bumper limiter shows both re-/co-deposition and erosion. The tritium images for all tiles measured are strongly correlated with erosion and deposition patterns, and long-term tritium retention was found in the re-/co-depositions and flakes. The CFC tiles located at erosion dominated areas clearly showed their woven structure in their tritium images owing to different erosion yields between fibers and matrix. Significantly high tritium retention was observed on all sides of the erosion tiles, indicating carbon transport via repetition of local erosion/deposition cycles

  15. The potential of ground gravity measurements to validate GRACE data

    Directory of Open Access Journals (Sweden)

    D. Crossley

    2003-01-01

    Full Text Available New satellite missions are returning high precision, time-varying, satellite measurements of the Earth’s gravity field. The GRACE mission is now in its calibration/- validation phase and first results of the gravity field solutions are imminent. We consider here the possibility of external validation using data from the superconducting gravimeters in the European sub-array of the Global Geodynamics Project (GGP as ‘ground truth’ for comparison with GRACE. This is a pilot study in which we use 14 months of 1-hour data from the beginning of GGP (1 July 1997 to 30 August 1998, when the Potsdam instrument was relocated to South Africa. There are 7 stations clustered in west central Europe, and one station, Metsahovi in Finland. We remove local tides, polar motion, local and global air pressure, and instrument drift and then decimate to 6-hour samples. We see large variations in the time series of 5–10µgal between even some neighboring stations, but there are also common features that correlate well over the 427-day period. The 8 stations are used to interpolate a minimum curvature (gridded surface that extends over the geographical region. This surface shows time and spatial coherency at the level of 2– 4µgal over the first half of the data and 1–2µgal over the latter half. The mean value of the surface clearly shows a rise in European gravity of about 3µgal over the first 150 days and a fairly constant value for the rest of the data. The accuracy of this mean is estimated at 1µgal, which compares favorably with GRACE predictions for wavelengths of 500 km or less. Preliminary studies of hydrology loading over Western Europe shows the difficulty of correlating the local hydrology, which can be highly variable, with large-scale gravity variations.Key words. GRACE, satellite gravity, superconducting gravimeter, GGP, ground truth

  16. Measurement of Spectral Functions of Ultracold Atoms in Disordered Potentials

    Science.gov (United States)

    Volchkov, Valentin V.; Pasek, Michael; Denechaud, Vincent; Mukhtar, Musawwadah; Aspect, Alain; Delande, Dominique; Josse, Vincent

    2018-02-01

    We report on the measurement of the spectral functions of noninteracting ultracold atoms in a three-dimensional disordered potential resulting from an optical speckle field. Varying the disorder strength by 2 orders of magnitude, we observe the crossover from the "quantum" perturbative regime of low disorder to the "classical" regime at higher disorder strength, and find an excellent agreement with numerical simulations. The method relies on the use of state-dependent disorder and the controlled transfer of atoms to create well-defined energy states. This opens new avenues for experimental investigations of three-dimensional Anderson localization.

  17. Quantum Mechanical Determination of Potential Energy Surfaces for TiO and H2O

    Science.gov (United States)

    Langhoff, Stephen R.

    1996-01-01

    We discuss current ab initio methods for determining potential energy surfaces, in relation to the TiO and H2O molecules, both of which make important contributions to the opacity of oxygen-rich stars. For the TiO molecule we discuss the determination of the radiative lifetimes of the excited states and band oscillator strengths for both the triplet and singlet band systems. While the theoretical radiative lifetimes for TiO agree well with recent measurements, the band oscillator strengths differ significantly from those currently employed in opacity calculations. For the H2O molecule we discuss the current results for the potential energy and dipole moment ground state surfaces generated at NASA Ames. We show that it is necessary to account for such effects as core-valence Correlation energy to generate a PES of near spectroscopic accuracy. We also describe how we solve the ro-vibrational problem to obtain the line positions and intensities that are needed for opacity sampling.

  18. Preliminary GRS Measurement of Chlorine Distribution on Surface of Mars

    Science.gov (United States)

    Keller, J. M.; Boynton, W. V.; Taylor, G. J.; Hamara, D.; Janes, D. M.; Kerry, K.

    2003-12-01

    Ongoing measurements with the Gamma Ray Spectrometer (GRS) aboard Mars Odyssey provide preliminary detection of chlorine at the surface of Mars. Summing all data since boom deployment and using a forward calculation model, we estimate values for chlorine concentration at 5° resolution. Rebinning this data and smoothing with a 15-degree-radius boxcar filter reveal regions of noticeable chlorine enrichment at scales larger than the original 5° resolution and allow for preliminary comparison with previous Mars datasets. Analyzing chlorine concentrations within 30 degrees of the equator, we find a negative correlation with thermal inertia (R2=0.55) and positive correlation with albedo (R2=0.52), indicating that chlorine is associated with fine, non-rock surface materials. Although possibly a smoothing artifact, the spatial correlation is more noticeable in the region covering Tharsis and Amazonis than around Arabia and Elysium. Additionally, a noticeable region of chlorine enrichment appears west of Tharsis Montes ( ˜0 to 20N, ˜110 to 150W) and chlorine concentration is estimated to vary in the equatorial region by over a factor of two. A simplified two-component model involving chlorine-poor rocks and a homogenous chlorine-rich fine material requires rock abundance to vary from zero to over 50%, a result inconsistent with previous measurements and models. In addition to variations in rock composition and distribution, substantial variations in chlorine content of various types of fine materials including dust, sand, and duricrust appear important in explaining this preliminary observation. Surprisingly, visual comparison of surface units mapped by Christensen and Moore (1992) does not show enrichment in chlorine associated with regions of indurated surfaces, where cementation has been proposed. Rather, Tharsis, a region of active deposition with proposed mantling of 0.1 to 2 meters of recent dust (Christensen 1986), shows the greatest chlorine signal. In light of

  19. Autonomous target recognition using remotely sensed surface vibration measurements

    Science.gov (United States)

    Geurts, James; Ruck, Dennis W.; Rogers, Steven K.; Oxley, Mark E.; Barr, Dallas N.

    1993-09-01

    The remotely measured surface vibration signatures of tactical military ground vehicles are investigated for use in target classification and identification friend or foe (IFF) systems. The use of remote surface vibration sensing by a laser radar reduces the effects of partial occlusion, concealment, and camouflage experienced by automatic target recognition systems using traditional imagery in a tactical battlefield environment. Linear Predictive Coding (LPC) efficiently represents the vibration signatures and nearest neighbor classifiers exploit the LPC feature set using a variety of distortion metrics. Nearest neighbor classifiers achieve an 88 percent classification rate in an eight class problem, representing a classification performance increase of thirty percent from previous efforts. A novel confidence figure of merit is implemented to attain a 100 percent classification rate with less than 60 percent rejection. The high classification rates are achieved on a target set which would pose significant problems to traditional image-based recognition systems. The targets are presented to the sensor in a variety of aspects and engine speeds at a range of 1 kilometer. The classification rates achieved demonstrate the benefits of using remote vibration measurement in a ground IFF system. The signature modeling and classification system can also be used to identify rotary and fixed-wing targets.

  20. Measuring surface energy and evapotranspiration across Caribbean mangrove forests

    Science.gov (United States)

    Lagomasino, D.; Fatoyinbo, T. E.; Price, R.

    2014-12-01

    Coastal mangroves lose large amounts of water through evapotranspiration (ET) that can be equivalent to the amount of annual rainfall in certain years. Satellite remote sensing has been used to estimate surface energy and ET variability in many forested ecosystems, yet has been widely overlooked in mangrove forests. Using a combination of long-term datasets (30-year) acquired from the NASA Landsat 5 and 7 satellite databases, the present study investigated ET and surface energy balance variability between two mangrove forest sites in the Caribbean: 1) Everglades National Park (ENP; Florida, USA) and 2) Sian Ka'an Biosphere Reserve (SKBR; Quintana Roo, Mexico). A satellite-derived surface energy balance model was used to estimate ET in tall and scrub mangroves environments at ENP and SKBR. Results identified significant differences in soil heat flux measurements and ET between the tall and scrub mangrove environments. Scrub mangroves exhibited the highest soil heat flux coincident with the lowest biophysical indices (i.e., Fractional Vegetation Cover, Normalized Difference Vegetation Index, and Soil-Adjusted Vegetation Index) and ET rates. Mangrove damage and mortality was observed on the satellite images following strong tropical storms and associated with anthropogenic modifications and resulted in low values in spectral vegetation indices, higher soil heat flux, and higher ET. Recovery of the spectral characteristics, soil heat flux and ET was within 1-2 years following hurricane disturbance while, degradation caused by human disturbance persisted for many years. Remotely sensed ET of mangrove forests can provide estimates over a few decades and provide us with some understanding of how these environments respond to disturbances to the landscape in periods where no ground data exists or in locations that are difficult to access. Moreover, relationships between energy and water balance components developed for the coastal mangroves of Florida and Mexico could be

  1. Surface potential-governed cellular osteogenic differentiation on ferroelectric polyvinylidene fluoride trifluoroethylene films.

    Science.gov (United States)

    Tang, Bolin; Zhang, Bo; Zhuang, Junjun; Wang, Qi; Dong, Lingqing; Cheng, Kui; Weng, Wenjian

    2018-05-02

    Surface potential of biomaterials can dramatically influence cellular osteogenic differentiation. In this work, a wide range of surface potential on ferroelectric polyvinylidene fluoride trifluoroethylene (P(VDF-TrFE)) films was designed to get insight into the interfacial interaction of cell-charged surface. The P(VDF-TrFE) films poled by contact electric poling at various electric fields obtained well stabilized surface potential, with wide range from -3 to 915 mV. The osteogenic differentiation level of cells cultured on the films was strongly dependent on surface potential and reached the optimum at 391 mV in this system. Binding specificity assay indicated that surface potential could effectively govern the binding state of the adsorbed fibronectin (FN) with integrin. Molecular dynamic (MD) simulation further revealed that surface potential brought a significant difference in the relative distance between RGD and synergy PHSRN sites of adsorbed FN, resulting in a distinct integrin-FN binding state. These results suggest that the full binding of integrin α5β1 with both RGD and PHSRN sites of FN possesses a strong ability to activate osteogenic signaling pathway. This work sheds light on the underlying mechanism of osteogenic differentiation behavior on charged material surfaces, and also provides a guidance for designing a reasonable charged surface to enhance osteogenic differentiation. The ferroelectric P(VDF-TrFE) films with steady and a wide range of surface potential were designed to understand underlying mechanism of cell-charged surface interaction. The results showed that the charged surface well favored upregulation of osteogenic differentiation of MC3T3-E1 cells, and more importantly, a highest level occurred on the film with a moderate surface potential. Experiments and molecular dynamics simulation demonstrated that the surface potential could govern fibronectin conformation and then the integrin-fibronectin binding. We propose that a full binding

  2. Lean Principles’Potential Measurement Framework for Service Organization

    Directory of Open Access Journals (Sweden)

    M. D. Vadhvani

    2016-06-01

    Full Text Available Role of service sector can be considered vital as these industries are accountable for accelerating the major functions of the secondary organizations. Hence it is a very important element of economy in enhancing competitive dimensions- quality, flexibility, cost and delivery. Improvement initiatives such as Total Quality Management, Lean Practices, and Leansigma focus on increasing the competitive dimensions. Among these Lean Practices are having the inherent principles of reducing the cost and increasing the quality by focusing the non value added activities from the value chain of the service or product. Lean Principles (LPs are being practiced since long by the organizations of secondary sectors and followed by that of the tertiary sectors. Albeit the reported improvement achieved are limited by the drawbacks such as lack of proper set of guidelines, partial features of measurable characteristics, lack of guideline for measurement. Present work proposes a measurement frame work with aids of flowchart and questionnaire for measuring the potential of LPs in service organization which help them to take accompanying initiatives to implement the LPs.

  3. An Analysis of Fundamental Mode Surface Wave Amplitude Measurements

    Science.gov (United States)

    Schardong, L.; Ferreira, A. M.; van Heijst, H. J.; Ritsema, J.

    2014-12-01

    Seismic tomography is a powerful tool to decipher the Earth's interior structure at various scales. Traveltimes of seismic waves are widely used to build velocity models, whereas amplitudes are still only seldomly accounted for. This mainly results from our limited ability to separate the various physical effects responsible for observed amplitude variations, such as focussing/defocussing, scattering and source effects. We present new measurements from 50 global earthquakes of fundamental-mode Rayleigh and Love wave amplitude anomalies measured in the period range 35-275 seconds using two different schemes: (i) a standard time-domain amplitude power ratio technique; and (ii) a mode-branch stripping scheme. For minor-arc data, we observe amplitude anomalies with respect to PREM in the range of 0-4, for which the two measurement techniques show a very good overall agreement. We present here a statistical analysis and comparison of these datasets, as well as comparisons with theoretical calculations for a variety of 3-D Earth models. We assess the geographical coherency of the measurements, and investigate the impact of source, path and receiver effects on surface wave amplitudes, as well as their variations with frequency in a wider range than previously studied.

  4. Charging effects and surface potential variations of Cu-based nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, D., E-mail: daniela.gomes@fct.unl.pt [i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica (Portugal); Calmeiro, T.R.; Nandy, S.; Pinto, J.V.; Pimentel, A.; Barquinha, P. [i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica (Portugal); Carvalho, P.A. [SINTEF Materials and Chemistry, PB 124 Blindern, NO-0314, Oslo (Norway); CeFEMA, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisboa (Portugal); Walmsley, J.C. [SINTEF Materials and Chemistry, Materials and Nanotechnology, Høgskoleringen 5, 7034 Trondheim (Norway); Fortunato, E., E-mail: emf@fct.unl.pt [i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica (Portugal); Martins, R., E-mail: rm@uninova.pt [i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica (Portugal)

    2016-02-29

    The present work reports charging effects and surface potential variations in pure copper, cuprous oxide and cupric oxide nanowires observed by electrostatic force microscopy (EFM) and Kelvin probe force microscopy (KPFM). The copper nanowires were produced by wet synthesis, oxidation into cuprous oxide nanowires was achieved through microwave irradiation and cupric oxide nanowires were obtained via furnace annealing in atmospheric conditions. Structural characterization of the nanowires was carried out by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. During the EFM experiments the electrostatic field of the positive probe charged negatively the Cu-based nanowires, which in turn polarized the SiO{sub 2} dielectric substrate. Both the probe/nanowire capacitance as well as the substrate polarization increased with the applied bias. Cu{sub 2}O and CuO nanowires behaved distinctively during the EFM measurements in accordance with their band gap energies. The work functions (WF) of the Cu-based nanowires, obtained by KPFM measurements, yielded WF{sub CuO} > WF{sub Cu} > WF{sub Cu{sub 2O}}. - Highlights: • Charge distribution study in Cu, Cu{sub 2}O and CuO nanowires through electrostatic force microscopy • Structural/surface defect role on the charge distribution along the Cu nanowires • Determination of the nanowire work functions by Kelvin probe force microscopy • Three types of nanowires give a broad idea of charge behavior on Cu based-nanowires.

  5. Characterization of gloss properties of differently treated polymer coating surfaces by surface clarity measurement methodology.

    Science.gov (United States)

    Gruber, Dieter P; Buder-Stroisznigg, Michael; Wallner, Gernot; Strauß, Bernhard; Jandel, Lothar; Lang, Reinhold W

    2012-07-10

    With one measurement configuration, existing gloss measurement methodologies are generally restricted to specific gloss levels. A newly developed image-analytical gloss parameter called "clarity" provides the possibility to describe the perceptual result of a broad range of different gloss levels with one setup. In order to analyze and finally monitor the perceived gloss of products, a fast and flexible method also for the automated inspection is highly demanded. The clarity parameter is very fast to calculate and therefore usable for fast in-line surface inspection. Coated metal specimens were deformed by varying degree and polished afterwards in order to study the clarity parameter regarding the quantification of varying surface gloss types and levels. In order to analyze the correlation with the human gloss perception a study was carried out in which experts were asked to assess gloss properties of a series of surface samples under standardized conditions. The study confirmed clarity to exhibit considerably better correlation to the human perception than alternative gloss parameters.

  6. Influence of Surface Adsorption on Work Function Measurements on Gold-Platinum Interface Using Scanning Kelvin Probe Microscopy

    International Nuclear Information System (INIS)

    Mugo, Simon; Yuan Jun

    2012-01-01

    Surface potential difference (SPD) on freshly coated gold and platinum electrodes have been found to be much smaller than bulk work functions consideration and to be dependent on time. We show these discrepancies arise due to formation of surface dipoles caused by adsorbed contaminants in ambient environments. The process is reversible by gentle annealing consistent with contaminant hypothesis. Examination of potential changes on individual electrodes suggest that the Pt surface is more sensitive to ambient conditions than the Au surface in accordance with their relative chemical activities. The result has great implication for interpretation of Kelvin probe measurements obtained on practical devices exposed to ambient environments.

  7. Online monitoring of Mezcal fermentation based on redox potential measurements.

    Science.gov (United States)

    Escalante-Minakata, P; Ibarra-Junquera, V; Rosu, H C; De León-Rodríguez, A; González-García, R

    2009-01-01

    We describe an algorithm for the continuous monitoring of the biomass and ethanol concentrations as well as the growth rate in the Mezcal fermentation process. The algorithm performs its task having available only the online measurements of the redox potential. The procedure combines an artificial neural network (ANN) that relates the redox potential to the ethanol and biomass concentrations with a nonlinear observer-based algorithm that uses the ANN biomass estimations to infer the growth rate of this fermentation process. The results show that the redox potential is a valuable indicator of the metabolic activity of the microorganisms during Mezcal fermentation. In addition, the estimated growth rate can be considered as a direct evidence of the presence of mixed culture growth in the process. Usually, mixtures of microorganisms could be intuitively clear in this kind of processes; however, the total biomass data do not provide definite evidence by themselves. In this paper, the detailed design of the software sensor as well as its experimental application is presented at the laboratory level.

  8. Measurements of the sheath potential in low density plasmas

    International Nuclear Information System (INIS)

    Bradley, J.W.; Khamis, R.A.; Sanduk, M.I.; Elliott, J.A.; Rusbridge, M.G.

    1992-01-01

    We have measured the sheath potential around a probe in a range of different plasma conditions in the UMIST, University of Manchester Institute of Science and Technology, quadrupole GOLUX and in a related experiment in which the plasma expands freely to supersonic velocity. In the latter case, the sheath potential agrees well with an appropriately modified form of the usual expression for a field-free plasma, for both hydrogen and argon plasmas. In GOLUX, however, the sheath potential is found to be significantly less than the accepted value, even when the magnetic field is taken into account. For the slow moving plasma in the outer part of the quadrupole confining field, we present both theoretical and experimental results showing that the reduction is due to truncation of the electron velocity distribution as the probe drains electrons from a closed flux tube faster than they can be replaced. In the central hot plasma, however, this explanation cannot apply. Here, the plasma is moving at about sonic speed and magnetic effects are weak. Nevertheless, the results are significantly different from both in the field free experiment. (author)

  9. Accurate fluid force measurement based on control surface integration

    Science.gov (United States)

    Lentink, David

    2018-01-01

    Nonintrusive 3D fluid force measurements are still challenging to conduct accurately for freely moving animals, vehicles, and deforming objects. Two techniques, 3D particle image velocimetry (PIV) and a new technique, the aerodynamic force platform (AFP), address this. Both rely on the control volume integral for momentum; whereas PIV requires numerical integration of flow fields, the AFP performs the integration mechanically based on rigid walls that form the control surface. The accuracy of both PIV and AFP measurements based on the control surface integration is thought to hinge on determining the unsteady body force associated with the acceleration of the volume of displaced fluid. Here, I introduce a set of non-dimensional error ratios to show which fluid and body parameters make the error negligible. The unsteady body force is insignificant in all conditions where the average density of the body is much greater than the density of the fluid, e.g., in gas. Whenever a strongly deforming body experiences significant buoyancy and acceleration, the error is significant. Remarkably, this error can be entirely corrected for with an exact factor provided that the body has a sufficiently homogenous density or acceleration distribution, which is common in liquids. The correction factor for omitting the unsteady body force, {{{ {ρ f}} {1 - {ρ f} ( {{ρ b}+{ρ f}} )}.{( {{{{ρ }}b}+{ρ f}} )}}} , depends only on the fluid, {ρ f}, and body, {{ρ }}b, density. Whereas these straightforward solutions work even at the liquid-gas interface in a significant number of cases, they do not work for generalized bodies undergoing buoyancy in combination with appreciable body density inhomogeneity, volume change (PIV), or volume rate-of-change (PIV and AFP). In these less common cases, the 3D body shape needs to be measured and resolved in time and space to estimate the unsteady body force. The analysis shows that accounting for the unsteady body force is straightforward to non

  10. Surface Potential and Particle Size Effect on the Rate of Perikinetic Coagulation

    International Nuclear Information System (INIS)

    Molina-Bolivar, J. A.; Galisteo-Gonzalez, F.; Cabrerizo-Vilchez, M.; Hidalgo-alvarez, R.

    1998-01-01

    The diffusion-controlled rapid coagulation rate of monodisperse polystyrene particles in aqueous solutions has been measured with a low angle scattering apparatus (nephelometer). We have refined this technique by using a narrow scattering flow cell and a pneumatic addicting-mixing device to introduce the salt solution and the latex sample in the cell. Coagulation rate constants were determined from analysis of the scattered light intensity dependence with time at an angle of 4.5 degree centigrade ± 1 degree centigrade. Experiments were designed to check the effects of particle size, surface potential and counterion valency on rapid coagulation constant. The particle ranged in diameter from 151 nm to 530 nm. The results are compared with the predictions of Smoluchowski's theory. Experiments to obtain the stability diagrams and the critical coagulation concentration of latexes have been performed. (Author) 31 refs

  11. 2D Analytical Modeling of Magnetic Vector Potential in Surface Mounted and Surface Inset Permanent Magnet Machines

    Directory of Open Access Journals (Sweden)

    A. Jabbari

    2017-12-01

    Full Text Available A 2D analytical method for magnetic vector potential calculation in inner rotor surface mounted and surface inset permanent magnet machines considering slotting effects, magnetization orientation and winding layout has been proposed in this paper. The analytical method is based on the resolution of Laplace and Poisson equations as well as Maxwell equation in quasi- Cartesian coordinate by using sub-domain method and hyperbolic functions. The developed method is applied on the performance computation of two prototypes surface mounted permanent magnet motors and two prototypes surface inset permanent magnet motors. A radial and a parallel magnetization orientation is considered for each type of motor. The results of these models are validated through FEM method.

  12. Junction Potentials Bias Measurements of Ion Exchange Membrane Permselectivity.

    Science.gov (United States)

    Kingsbury, Ryan S; Flotron, Sophie; Zhu, Shan; Call, Douglas F; Coronell, Orlando

    2018-04-17

    Ion exchange membranes (IEMs) are versatile materials relevant to a variety of water and waste treatment, energy production, and industrial separation processes. The defining characteristic of IEMs is their ability to selectively allow positive or negative ions to permeate, which is referred to as permselectivity. Measured values of permselectivity that equal unity (corresponding to a perfectly selective membrane) or exceed unity (theoretically impossible) have been reported for cation exchange membranes (CEMs). Such nonphysical results call into question our ability to correctly measure this crucial membrane property. Because weighing errors, temperature, and measurement uncertainty have been shown to not explain these anomalous permselectivity results, we hypothesized that a possible explanation are junction potentials that occur at the tips of reference electrodes. In this work, we tested this hypothesis by comparing permselectivity values obtained from bare Ag/AgCl wire electrodes (which have no junction) to values obtained from single-junction reference electrodes containing two different electrolytes. We show that permselectivity values obtained using reference electrodes with junctions were greater than unity for CEMs. In contrast, electrodes without junctions always produced permselectivities lower than unity. Electrodes with junctions also resulted in artificially low permselectivity values for AEMs compared to electrodes without junctions. Thus, we conclude that junctions in reference electrodes introduce two biases into results in the IEM literature: (i) permselectivity values larger than unity for CEMs and (ii) lower permselectivity values for AEMs compared to those for CEMs. These biases can be avoided by using electrodes without a junction.

  13. Measurement of pressure on a surface using bubble acoustic resonances

    International Nuclear Information System (INIS)

    Aldham, Ben; Manasseh, Richard; Liffman, Kurt; Šutalo, Ilija D; Illesinghe, Suhith; Ooi, Andrew

    2010-01-01

    The frequency response of gas bubbles as a function of liquid ambient pressure was measured and compared with theory. A bubble size with equivalent spherical radius of 2.29 mm was used over a frequency range of 1000–1500 Hz. The ultimate aim is to develop an acoustic sensor that can measure static pressure and is sensitive to variations as small as a few kPa. The classical bubble resonance frequency is known to vary with ambient pressure. Experiments were conducted with a driven bubble in a pressurizable tank with a signal processing system designed to extract the resonant peak. Since the background response of the containing tank is significant, particularly near tank-modal resonances, it must be carefully removed from the bubble response signal. A dual-hydrophone method was developed to allow rapid and reliable real-time measurements. The expected pressure dependence was found. In order to obtain a reasonable match with theory, the classical theory was modified by the introduction of a 'mirror bubble' to account for the influence of a nearby surface. (technical design note)

  14. Quantum Nuclear Extension of Electron Nuclear Dynamics on Folded Effective-Potential Surfaces

    DEFF Research Database (Denmark)

    Hall, B.; Deumens, E.; Ohrn, Y.

    2014-01-01

    A perennial problem in quantum scattering calculations is accurate theoretical treatment of low energy collisions. We propose a method of extracting a folded, nonadiabatic, effective potential energy surface from electron nuclear dynamics (END) trajectories; we then perform nuclear wave packet...

  15. On quantum motion of particle in linear potential bounded by perfectly reflecting plane and parabolic surfaces

    International Nuclear Information System (INIS)

    Pokotilovskij, Yu.N.

    1999-01-01

    The motion of a particle in the linear potential bounded by an inclined plane or parabolic surfaces is considered. The quantization of energy and wave functions is obtained numerically by the separation of the variables method

  16. Helicon plasma potential measurements using a heavy ion beam probe

    International Nuclear Information System (INIS)

    P. Schoch; K. Connor; J. Si

    2005-01-01

    A Heavy Ion Beam Probe, HIBP, has been installed on a helicon plasma device. The objective was to measure plasma fluctuations at the 13.55MHz RF frequency. This offers a unique challenge for the HIBP, because the transit time of the probing ion is long compared to the fluctuations of interest. For previous HIBPs, the transit time has been short compared to the period of the fluctuations which permits one to assume that the magnetic and electric fields are static. Modeling has shown that the diagnostic will still accurately measure the average potential. The fluctuating potential was to be detected but the absolute magnitude is difficult to determine with signal from a single point. However, modeling indicates multipoint measurements will allow one to resolve the absolute fluctuation magnitude. Work supported by DOE Grant No. DE-FG02-99ER5452985 During the funding of this grant, a helicon plasma discharge device was built and operated. A Heavy Ion Beam Probe primary system was installed and operated. A primary beam detector was installed and primary beam was detected both with and without plasma. Attempts were made to detect secondary ions using the primary beam detector, without success. Given the lack of a detectable signal, the energy analyzer of the HIBP system was never installed. It is available for installation if there is a reason to do so in the future. Analysis of the system indicated that the plasma electron temperature, estimated to be a few eV, was the likely reason for the lack of detectable secondary ions. A change of ion species to either Boron or Magnesium would greatly increase the signal, but neither of these ions have been used in a HIBP system. The ion source used in this system is made by using a charge exchange process to create a zeolite loaded with the desired ion. Attempts were made to use charge exchange to load Magnesium into a zeolite, and were not successful. It is felt that Magnesium and/or Boron zeolite sources could be created, but

  17. Surface Acoustic Wave Vibration Sensors for Measuring Aircraft Flutter

    Science.gov (United States)

    Wilson, William C.; Moore, Jason P.; Juarez, Peter D.

    2016-01-01

    Under NASA's Advanced Air Vehicles Program the Advanced Air Transport Technology (AATT) Project is investigating flutter effects on aeroelastic wings. To support that work a new method for measuring vibrations due to flutter has been developed. The method employs low power Surface Acoustic Wave (SAW) sensors. To demonstrate the ability of the SAW sensor to detect flutter vibrations the sensors were attached to a Carbon fiber-reinforced polymer (CFRP) composite panel which was vibrated at six frequencies from 1Hz to 50Hz. The SAW data was compared to accelerometer data and was found to resemble sine waves and match each other closely. The SAW module design and results from the tests are presented here.

  18. Ion-step method for surface potential sensing of silicon nanowires

    NARCIS (Netherlands)

    Chen, S.; van Nieuwkasteele, Jan William; van den Berg, Albert; Eijkel, Jan C.T.

    2016-01-01

    This paper presents a novel stimulus-response method for surface potential sensing of silicon nanowire (Si NW) field-effect transistors. When an "ion-step" from low to high ionic strength is given as a stimulus to the gate oxide surface, an increase of double layer capacitance is therefore expected.

  19. Delta self-consistent field method to obtain potential energy surfaces of excited molecules on surfaces

    DEFF Research Database (Denmark)

    Gavnholt, Jeppe; Olsen, Thomas; Engelund, Mads

    2008-01-01

    is a density-functional method closely resembling standard density-functional theory (DFT), the only difference being that in Delta SCF one or more electrons are placed in higher lying Kohn-Sham orbitals instead of placing all electrons in the lowest possible orbitals as one does when calculating the ground......-state energy within standard DFT. We extend the Delta SCF method by allowing excited electrons to occupy orbitals which are linear combinations of Kohn-Sham orbitals. With this extra freedom it is possible to place charge locally on adsorbed molecules in the calculations, such that resonance energies can...... be estimated, which is not possible in traditional Delta SCF because of very delocalized Kohn-Sham orbitals. The method is applied to N2, CO, and NO adsorbed on different metallic surfaces and compared to ordinary Delta SCF without our modification, spatially constrained DFT, and inverse...

  20. Method and apparatus for determining the spontaneous earth potential log from downhole gradient measurements

    International Nuclear Information System (INIS)

    Maciejewski, W. J.

    1985-01-01

    A method and apparatus for measuring the differential or gradient of an earth variable within a well bore (e.g., the spontaneous earth potential) and producing improved logs of this gradient or differential and its integral variable essentially free of any accumulated instrument and base line drift or error. The differential spontaneous potential of an earth formation traversed by a well bore is measured at repeated multiple depths by moving a pair of closely spaced electrodes through the well bore wherein each electrode is electrically insulated externally from the other and from a third downhole local ground (such as the well tool cable) to which each is internally resistively referenced. The measured electrical potential across the closely spaced electrodes is amplified and digitized before being transmitted to the earth's surface, whereupon an averaged value of such differential measurements within a traveling data window of predetermined length and adjacent to each successive measurement is used to adjust for base line drift, noise and instrument induced error. The resulting compensated differential logs are integrated, resulting in spontaneous potential logs of improved character

  1. Hoof accelerations and ground reaction forces of Thoroughbred racehorses measured on dirt, synthetic, and turf track surfaces.

    Science.gov (United States)

    Setterbo, Jacob J; Garcia, Tanya C; Campbell, Ian P; Reese, Jennifer L; Morgan, Jessica M; Kim, Sun Y; Hubbard, Mont; Stover, Susan M

    2009-10-01

    To compare hoof acceleration and ground reaction force (GRF) data among dirt, synthetic, and turf surfaces in Thoroughbred racehorses. 3 healthy Thoroughbred racehorses. Forelimb hoof accelerations and GRFs were measured with an accelerometer and a dynamometric horseshoe during trot and canter on dirt, synthetic, and turf track surfaces at a racecourse. Maxima, minima, temporal components, and a measure of vibration were extracted from the data. Acceleration and GRF variables were compared statistically among surfaces. The synthetic surface often had the lowest peak accelerations, mean vibration, and peak GRFs. Peak acceleration during hoof landing was significantly smaller for the synthetic surface (mean + or - SE, 28.5g + or - 2.9g) than for the turf surface (42.9g + or - 3.8g). Hoof vibrations during hoof landing for the synthetic surface were dirt and turf surfaces. Peak GRF for the synthetic surface (11.5 + or - 0.4 N/kg) was 83% and 71% of those for the dirt (13.8 + or - 0.3 N/kg) and turf surfaces (16.1 + or - 0.7 N/kg), respectively. The relatively low hoof accelerations, vibrations, and peak GRFs associated with the synthetic surface evaluated in the present study indicated that synthetic surfaces have potential for injury reduction in Thoroughbred racehorses. However, because of the unique material properties and different nature of individual dirt, synthetic, and turf racetrack surfaces, extending the results of this study to encompass all track surfaces should be done with caution.

  2. The potential of continuous, local atomic clock measurements for earthquake prediction and volcanology

    Directory of Open Access Journals (Sweden)

    Bondarescu Mihai

    2015-01-01

    Full Text Available Modern optical atomic clocks along with the optical fiber technology currently being developed can measure the geoid, which is the equipotential surface that extends the mean sea level on continents, to a precision that competes with existing technology. In this proceeding, we point out that atomic clocks have the potential to not only map the sea level surface on continents, but also look at variations of the geoid as a function of time with unprecedented timing resolution. The local time series of the geoid has a plethora of applications. These include potential improvement in the predictions of earthquakes and volcanoes, and closer monitoring of ground uplift in areas where hydraulic fracturing is performed.

  3. Channel Storage change: a new remote sensed surface water measurement

    Science.gov (United States)

    Coss, S. P.; Durand, M. T.; Yi, Y.; Guo, Q.; Shum, C. K.; Allen, G. H.; Pavelsky, T.

    2017-12-01

    Here we present river channel storage change (CSC) measurements for 17 major world rivers from 2002-2016. We combined interpolated daily 1 km resolution Global River Radar Altimeter Time Series (GRRATS) river surface elevation data with static widths from the global river Global River Widths from Landsat (GRWL) dataset, to generate preliminary channel storage measurements. CSC is a previously unmeasured component of the terrestrial water balance It is a fundamental Earth science quantity with global bearing on floodplains, ecology, and geochemistry. CSC calculations require only remote sensed data, making them an ideal tool for studying remote regions where hydrological data is not easily accessible. CSC is uniquely suited to determine the role of hydrologic and hydraulic controls in basins with strong seasonal cycles (freeze-up and break-up). The cumulative CSC anomaly can impart spatial details that discharge measurements cannot. With this new measurement, we may be able to determine critical hydrological and hydraulic controls on rapidly changing systems like Arctic rivers. Results for Mississippi River indicate that peak CSC anomaly was the highest in 2011 (12.6 km3) and minimum CSC anomaly was in 2012 (-12.2 km3). Peak CSC has most frequently occurs in May (5 years), but has come as late in the year as July, and as early as January. Results for the Yukon River indicate that peak CSC anomaly was the highest in 2013 (13.9 km3) and minimum CSC anomaly was in 2010 (-14.2 km3). Peak CSC has most frequently come in early to mid-June (4-18), but has occurred in May (19-31) four years in the study period (three of the last 6 years) and once on April 30th.

  4. Spontaneous potential and telluric measurements on Rainier Mesa relaed to the NPE

    Energy Technology Data Exchange (ETDEWEB)

    Sweeney, J.J. [Lawrence Livermore National Lab., CA (United States)

    1994-12-31

    We made measurements of spontaneous potential (SP) on Rainier Mesa to see if changes in subsurface electrical properties of rock related to the Non-Proliferation Experiment (NPE) explosion can be detected at the surface. A north-south line, repeated 3 times and running within 50 m of surface ground zero (SGZ) of Hunter`s Trophy and within 20 m of SGZ of the NPE, was measured before and after the NPE. An east-west line, with one end within 20 m of SGZ of the NPE was also run before and after the NPE. High values of surface potential along the north-south line in the vicinity of the NPE apparently moved northward after the detonation. A similar change was not noted on the east-west line. A telluric line (0.025-0.1 Hz and 8.0 Hz) was also run prior to the NPE along the same north-south line as the SP measurement, but farther to the west of SGZ for Hunter`s Trophy. There is a prominent high in the 8 Hz data in the northern part that may be related to a former nuclear test, but it could also be related to local geology. Results from these geophysical methods, while showing some promise for use in an on-site monitoring regime, also emphasize the need for repeatable background reference data.

  5. Modeling uranium(VI) adsorption onto montmorillonite under varying carbonate concentrations: A surface complexation model accounting for the spillover effect on surface potential

    Science.gov (United States)

    Tournassat, C.; Tinnacher, R. M.; Grangeon, S.; Davis, J. A.

    2018-01-01

    The prediction of U(VI) adsorption onto montmorillonite clay is confounded by the complexities of: (1) the montmorillonite structure in terms of adsorption sites on basal and edge surfaces, and the complex interactions between the electrical double layers at these surfaces, and (2) U(VI) solution speciation, which can include cationic, anionic and neutral species. Previous U(VI)-montmorillonite adsorption and modeling studies have typically expanded classical surface complexation modeling approaches, initially developed for simple oxides, to include both cation exchange and surface complexation reactions. However, previous models have not taken into account the unique characteristics of electrostatic surface potentials that occur at montmorillonite edge sites, where the electrostatic surface potential of basal plane cation exchange sites influences the surface potential of neighboring edge sites ('spillover' effect). A series of U(VI) - Na-montmorillonite batch adsorption experiments was conducted as a function of pH, with variable U(VI), Ca, and dissolved carbonate concentrations. Based on the experimental data, a new type of surface complexation model (SCM) was developed for montmorillonite, that specifically accounts for the spillover effect using the edge surface speciation model by Tournassat et al. (2016a). The SCM allows for a prediction of U(VI) adsorption under varying chemical conditions with a minimum number of fitting parameters, not only for our own experimental results, but also for a number of published data sets. The model agreed well with many of these datasets without introducing a second site type or including the formation of ternary U(VI)-carbonato surface complexes. The model predictions were greatly impacted by utilizing analytical measurements of dissolved inorganic carbon (DIC) concentrations in individual sample solutions rather than assuming solution equilibration with a specific partial pressure of CO2, even when the gas phase was

  6. Estimating costs and potentials of different methods to reduce the Swedish phosphorus load from agriculture to surface water.

    Science.gov (United States)

    Malmaeus, J M; Karlsson, O M

    2010-01-01

    This paper reviews 17 measures to reduce phosphorus leakage from Swedish agriculture to surface waters. Our aim is to evaluate the possible contribution from agriculture to achieve environmental goals including the Baltic Sea Action Plan. Using a regional approach integrating the variability in field specific characteristics, typical costs and national potential for the included measures may be estimated without identifying, e.g., suitable individual fields for implementation. The result may be helpful to select suitable measures but may also influence the design of environmental targets before they are determined. We find that the cheapest measures are reduced phosphorus content in animal food and fertilizer application supervision in pig farms, both measures with annual potentials of around 50t each, and costs of euro7 to euro11 kg(-1)yr(-1). The total potential of the listed measures is an annual phosphorus reduction to surface waters of 242t. If the most expensive measures are excluded (>euro1000 kg(-1)yr(-1)) and including retention in lakes the phosphorus transport to the sea could be reduced by 165 t yr(-1). This amount can be compared with the Swedish commitment in the Baltic Sea Action Plan (BSAP) to reduce input to the Baltic Proper by 290 t yr(-1).

  7. Nonlinear Growth Models as Measurement Models: A Second-Order Growth Curve Model for Measuring Potential.

    Science.gov (United States)

    McNeish, Daniel; Dumas, Denis

    2017-01-01

    Recent methodological work has highlighted the promise of nonlinear growth models for addressing substantive questions in the behavioral sciences. In this article, we outline a second-order nonlinear growth model in order to measure a critical notion in development and education: potential. Here, potential is conceptualized as having three components-ability, capacity, and availability-where ability is the amount of skill a student is estimated to have at a given timepoint, capacity is the maximum amount of ability a student is predicted to be able to develop asymptotically, and availability is the difference between capacity and ability at any particular timepoint. We argue that single timepoint measures are typically insufficient for discerning information about potential, and we therefore describe a general framework that incorporates a growth model into the measurement model to capture these three components. Then, we provide an illustrative example using the public-use Early Childhood Longitudinal Study-Kindergarten data set using a Michaelis-Menten growth function (reparameterized from its common application in biochemistry) to demonstrate our proposed model as applied to measuring potential within an educational context. The advantage of this approach compared to currently utilized methods is discussed as are future directions and limitations.

  8. Surface force measurements and simulations of mussel-derived peptide adhesives on wet organic surfaces.

    Science.gov (United States)

    Levine, Zachary A; Rapp, Michael V; Wei, Wei; Mullen, Ryan Gotchy; Wu, Chun; Zerze, Gül H; Mittal, Jeetain; Waite, J Herbert; Israelachvili, Jacob N; Shea, Joan-Emma

    2016-04-19

    Translating sticky biological molecules-such as mussel foot proteins (MFPs)-into synthetic, cost-effective underwater adhesives with adjustable nano- and macroscale characteristics requires an intimate understanding of the glue's molecular interactions. To help facilitate the next generation of aqueous adhesives, we performed a combination of surface forces apparatus (SFA) measurements and replica-exchange molecular dynamics (REMD) simulations on a synthetic, easy to prepare, Dopa-containing peptide (MFP-3s peptide), which adheres to organic surfaces just as effectively as its wild-type protein analog. Experiments and simulations both show significant differences in peptide adsorption on CH3-terminated (hydrophobic) and OH-terminated (hydrophilic) self-assembled monolayers (SAMs), where adsorption is strongest on hydrophobic SAMs because of orientationally specific interactions with Dopa. Additional umbrella-sampling simulations yield free-energy profiles that quantitatively agree with SFA measurements and are used to extract the adhesive properties of individual amino acids within the context of MFP-3s peptide adhesion, revealing a delicate balance between van der Waals, hydrophobic, and electrostatic forces.

  9. Skin denervation does not alter cortical potentials to surface concentric electrode stimulation: A comparison with laser evoked potentials and contact heat evoked potentials.

    Science.gov (United States)

    La Cesa, S; Di Stefano, G; Leone, C; Pepe, A; Galosi, E; Alu, F; Fasolino, A; Cruccu, G; Valeriani, M; Truini, A

    2018-01-01

    In the neurophysiological assessment of patients with neuropathic pain, laser evoked potentials (LEPs), contact heat evoked potentials (CHEPs) and the evoked potentials by the intraepidermal electrical stimulation via concentric needle electrode are widely agreed as nociceptive specific responses; conversely, the nociceptive specificity of evoked potentials by surface concentric electrode (SE-PREPs) is still debated. In this neurophysiological study we aimed at verifying the nociceptive specificity of SE-PREPs. We recorded LEPs, CHEPs and SE-PREPs in eleven healthy participants, before and after epidermal denervation produced by prolonged capsaicin application. We also used skin biopsy to verify the capsaicin-induced nociceptive nerve fibre loss in the epidermis. We found that whereas LEPs and CHEPs were suppressed after capsaicin-induced epidermal denervation, the surface concentric electrode stimulation of the same denervated skin area yielded unchanged SE-PREPs. The suppression of LEPs and CHEPs after nociceptive nerve fibre loss in the epidermis indicates that these techniques are selectively mediated by nociceptive system. Conversely, the lack of SE-PREP changes suggests that SE-PREPs do not provide selective information on nociceptive system function. Capsaicin-induced epidermal denervation abolishes laser evoked potentials (LEPs) and contact heat evoked potentials (CHEPs), but leaves unaffected pain-related evoked potentials by surface concentric electrode (SE-PREPs). These findings suggest that unlike LEPs and CHEPs, SE-PREPs are not selectively mediated by nociceptive system. © 2017 European Pain Federation - EFIC®.

  10. Development of a potential screening measure for adolescent depression.

    Science.gov (United States)

    Taouk, Mona; Meiser, Bettina; Hadzi-Pavlovic, Dusan; Dudley, Michael; Mitchell, Philip B

    2017-06-01

    Few adolescent-specific depression screening instruments have been developed in recent years using multi-method approaches (qualitative and quantitative), and some of those available have limitations with an adolescent audience. We describe the development of a potential measure - the Taouk Scale for Adolescent Depression. Draft items were informed by findings from focus groups and reviews by adolescents and healthcare professionals, resulting in a provisional 97-item scale. This was administered to a nation-wide sample of 3087 secondary students. Exploratory factor analysis was used in a development subset to examine dimensionality of items and reduce their number, with the final item set evaluated in a validation subset. Four reliable factors - negative outlook, emotional distress, behavioural changes and cognitive and somatic disturbances - were obtained from the exploratory factor analysis, resulting in a 28-item instrument, which was corroborated by confirmatory factor analysis. The final scale includes a number of novel items not included in current measures, i.e., whether respondents wear more black clothing than usual, deliberately damage property, take more risks, 'space out' at school and are engaged in substance abuse and/or increased sexual activity. The Taouk Scale for Adolescent Depression demonstrated sound psychometric properties and may have utility for future screening and future epidemiological purposes. It appears to be a valid and reliable screening instrument for adolescent depression that includes a number of novel items. Further research is necessary to confirm its criterion validity in clinically depressed samples.

  11. Measurement of the first ionization potential of lawrencium (element 103)

    CERN Document Server

    Sato, T K; Borschevsky, A; Stora, T; Sato, N; Kaneya, Y; Tsukada, K; Düllmann, Ch E; Eberhardt, K; Eliav, E; Ichikawa, S; Kaldor, U; Kratz, J V; Miyashita, S; Nagame, Y; Ooe, K; Osa, A; Renisch, D; Runke, J; Schädel, M; Thörle-Pospiech, P; Toyoshima, A; Trautmann, N

    2015-01-01

    The chemical properties of an element are primarily governed by the configuration of electrons in the valence shell. Relativistic effects influence the electronic structure of heavy elements in the sixth row of the periodic table, and these effects increase dramatically in the seventh row—including the actinides—even affecting ground-state configurations. Atomic s and p1/2 orbitals are stabilized by relativistic effects, whereas p3/2, d and f orbitals are destabilized, so that ground-state configurations of heavy elements may differ from those of lighter elements in the same group. The first ionization potential (IP1) is a measure of the energy required to remove one valence electron from a neutral atom, and is an atomic property that reflects the outermost electronic configuration. Precise and accurate experimental determination of IP1 gives information on the binding energy of valence electrons, and also, therefore, on the degree of relativistic stabilization. However, such measurements are hampered by ...

  12. Defining Tsunami Magnitude as Measure of Potential Impact

    Science.gov (United States)

    Titov, V. V.; Tang, L.

    2016-12-01

    The goal of tsunami forecast, as a system for predicting potential impact of a tsunami at coastlines, requires quick estimate of a tsunami magnitude. This goal has been recognized since the beginning of tsunami research. The work of Kajiura, Soloviev, Abe, Murty, and many others discussed several scales for tsunami magnitude based on estimates of tsunami energy. However, difficulties of estimating tsunami energy based on available tsunami measurements at coastal sea-level stations has carried significant uncertainties and has been virtually impossible in real time, before tsunami impacts coastlines. The slow process of tsunami magnitude estimates, including collection of vast amount of available coastal sea-level data from affected coastlines, made it impractical to use any tsunami magnitude scales in tsunami warning operations. Uncertainties of estimates made tsunami magnitudes difficult to use as universal scale for tsunami analysis. Historically, the earthquake magnitude has been used as a proxy of tsunami impact estimates, since real-time seismic data is available of real-time processing and ample amount of seismic data is available for an elaborate post event analysis. This measure of tsunami impact carries significant uncertainties in quantitative tsunami impact estimates, since the relation between the earthquake and generated tsunami energy varies from case to case. In this work, we argue that current tsunami measurement capabilities and real-time modeling tools allow for establishing robust tsunami magnitude that will be useful for tsunami warning as a quick estimate for tsunami impact and for post-event analysis as a universal scale for tsunamis inter-comparison. We present a method for estimating the tsunami magnitude based on tsunami energy and present application of the magnitude analysis for several historical events for inter-comparison with existing methods.

  13. Multi-station synthesis of early twentieth century surface atmospheric electricity measurements for upper tropospheric properties

    Directory of Open Access Journals (Sweden)

    R. G. Harrison

    2007-07-01

    Full Text Available The vertical columnar current density in the global atmospheric electrical circuit depends on the local columnar resistance. A simple model for the columnar resistance is suggested, which separates the local boundary layer component from the upper troposphere cosmic ray component, and calculates the boundary layer component from a surface measurement of air conductivity. This theory is shown to provide reasonable agreement with observations. One application of the simple columnar model theory is to provide a basis for the synthesis of surface atmospheric electrical measurements made simultaneously at several European sites. Assuming the ionospheric potential to be common above all the sites, the theoretical air-earth current density present in the absence of a boundary layer columnar resistance can be found by extrapolation. This is denoted the free troposphere limit air-earth current density, J0. Using early surface data from 1909 when no ionospheric potential data are available for corroboration, J0 is found to be ~6 pA m−2, although this is subject to uncertainties in the data and limitations in the theory. Later (1966–1971 European balloon and surface data give J0=2.4 pA m−2.

  14. A Classical Potential to Model the Adsorption of Biological Molecules on Oxidized Titanium Surfaces.

    Science.gov (United States)

    Schneider, Julian; Ciacchi, Lucio Colombi

    2011-02-08

    The behavior of titanium implants in physiological environments is governed by the thin oxide layer that forms spontaneously on the metal surface and mediates the interactions with adsorbate molecules. In order to study the adsorption of biomolecules on titanium in a realistic fashion, we first build up a model of an oxidized Ti surface in contact with liquid water by means of extensive first-principles molecular dynamics simulations. Taking the obtained structure as reference, we then develop a classical potential to model the Ti/TiOx/water interface. This is based on the mapping with Coulomb and Lennard-Jones potentials of the adsorption energy landscape of single water and ammonia molecules on the rutile TiO2(110) surface. The interactions with arbitrary organic molecules are obtained via standard combination rules to established biomolecular force fields. The transferability of our potential to the case of organic molecules adsorbing on the oxidized Ti surface is checked by comparing the classical potential energy surfaces of representative systems to quantum mechanical results at the level of density functional theory. Moreover, we calculate the heat of immersion of the TiO2 rutile surface and the detachment force of a single tyrosine residue from steered molecular dynamics simulations, finding good agreement with experimental reference data in both cases. As a first application, we study the adsorption behavior of the Arg-Gly-Asp (RGD) peptide on the oxidized titanium surface, focusing particularly on the calculation of the free energy of desorption.

  15. Potential energy surfaces of adsorbates on periodic substrates: Application of the Morse theory

    Czech Academy of Sciences Publication Activity Database

    Pick, Štěpán

    2009-01-01

    Roč. 79, č. 4 (2009), 045403-1-5 ISSN 1098-0121 Institutional research plan: CEZ:AV0Z40400503 Keywords : adsorbed layers * Morse potential * potential energy surfaces * substrates Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.475, year: 2009

  16. Potential energy surface from spectroscopic data in the photodissociation of polyatomic molecules

    International Nuclear Information System (INIS)

    Kim, Hwa Joong; Kim, Young Sik

    2001-01-01

    The time-dependent tracking inversion method is studied to extract the potential energy surface of the electronic excited state in the photodissociation of triatomic molecules. Based on the relay of the regularized inversion procedure and time-dependent wave packet propagation, the algorithm extracts the underlying potential energy surface piece by tracking the time-dependent data, which can be synthesized from Raman excitation profiles. We have demonstrated the algorithm to extract the potential energy surface of electronic excited state for NO 2 molecule where the wave packet split on a saddle-shaped surface. Finally, we describe the merits of the time-dependent tracking inversion method compared with the time-dependent inversion method and discussed several extensions of the algorithm

  17. A Method for Dimensional and Surface Optical Measurements Uncertainty Assessment on Micro Structured Surfaces Manufactured by Jet-ECM

    DEFF Research Database (Denmark)

    Quagliotti, Danilo; Tosello, Guido; Islam, Aminul

    2015-01-01

    Surface texture and step height measurements of electrochemically machined cavities have been compared among optical and tactile instruments. A procedure is introduced for correcting possible divergences among the instruments and, ultimately, for evaluating the measurement uncertainty according t...

  18. Laser Cooling and Trapping of Neutral Strontium for Spectroscopic Measurements of Casimir-Polder Potentials

    Science.gov (United States)

    Cook, Eryn C.

    Casimir and Casimir-Polder effects are forces between electrically neutral bodies and particles in vacuum, arising entirely from quantum fluctuations. The modification to the vacuum electromagnetic-field modes imposed by the presence of any particle or surface can result in these mechanical forces, which are often the dominant interaction at small separations. These effects play an increasingly critical role in the operation of micro- and nano-mechanical systems as well as miniaturized atomic traps for precision sensors and quantum-information devices. Despite their fundamental importance, calculations present theoretical and numeric challenges, and precise atom-surface potential measurements are lacking in many geometric and distance regimes. The spectroscopic measurement of Casimir-Polder-induced energy level shifts in optical-lattice trapped atoms offers a new experimental method to probe atom-surface interactions. Strontium, the current front-runner among optical frequency metrology systems, has demonstrated characteristics ideal for such precision measurements. An alkaline earth atom possessing ultra-narrow intercombination transitions, strontium can be loaded into an optical lattice at the "magic" wavelength where the probe transition is unperturbed by the trap light. Translation of the lattice will permit controlled transport of tightly-confined atomic samples to well-calibrated atom-surface separations, while optical transition shifts serve as a direct probe of the Casimir-Polder potential. We have constructed a strontium magneto-optical trap (MOT) for future Casimir-Polder experiments. This thesis will describe the strontium apparatus, initial trap performance, and some details of the proposed measurement procedure.

  19. Biofilm formation by Listeria monocytogenes on stainless steel surface and biotransfer potential

    Directory of Open Access Journals (Sweden)

    Maíra Maciel Mattos de Oliveira

    2010-03-01

    Full Text Available An experimental model was proposed to study biofilm formation by Listeria monocytogenes ATCC 19117 on AISI 304 (#4 stainless steel surface and biotransfer potential during this process. In this model, biofilm formation was conducted on the surface of stainless steel coupons, set on a stainless steel base with 4 divisions, each one supporting 21 coupons. Trypic Soy Broth was used as bacterial growth substrate, with incubation at 37 ºC and stirring of 50 rpm. The number of adhered cells was determined after 3, 48, 96, 144, 192 and 240 hours of biofilm formation and biotransfer potential from 96 hours. Stainless steel coupons were submitted to Scanning Electron Microscopy (SEM after 3, 144 and 240 hours. Based on the number of adhered cells and SEM, it was observed that L. monocytogenes adhered rapidly to the stainless steel surface, with mature biofilm being formed after 240 hours. The biotransfer potential of bacterium to substrate occurred at all the stages analyzed. The rapid capacity of adhesion to surface, combined with biotransfer potential throughout the biofilm formation stages, make L. monocytogenes a potential risk to the food industry. Both the experimental model developed and the methodology used were efficient in the study of biofilm formation by L. monocytogenes on stainless steel surface and biotransfer potential.

  20. Biofilm formation by Listeria monocytogenes on stainless steel surface and biotransfer potential.

    Science.gov (United States)

    de Oliveira, Maíra Maciel Mattos; Brugnera, Danilo Florisvaldo; Alves, Eduardo; Piccoli, Roberta Hilsdorf

    2010-01-01

    An experimental model was proposed to study biofilm formation by Listeria monocytogenes ATCC 19117 on AISI 304 (#4) stainless steel surface and biotransfer potential during this process. In this model, biofilm formation was conducted on the surface of stainless steel coupons, set on a stainless steel base with 4 divisions, each one supporting 21 coupons. Trypic Soy Broth was used as bacterial growth substrate, with incubation at 37 °C and stirring of 50 rpm. The number of adhered cells was determined after 3, 48, 96, 144, 192 and 240 hours of biofilm formation and biotransfer potential from 96 hours. Stainless steel coupons were submitted to Scanning Electron Microscopy (SEM) after 3, 144 and 240 hours. Based on the number of adhered cells and SEM, it was observed that L. monocytogenes adhered rapidly to the stainless steel surface, with mature biofilm being formed after 240 hours. The biotransfer potential of bacterium to substrate occurred at all the stages analyzed. The rapid capacity of adhesion to surface, combined with biotransfer potential throughout the biofilm formation stages, make L. monocytogenes a potential risk to the food industry. Both the experimental model developed and the methodology used were efficient in the study of biofilm formation by L. monocytogenes on stainless steel surface and biotransfer potential.

  1. Disordered electrical potential observed on the surface of SiO2 by electric field microscopy

    International Nuclear Information System (INIS)

    GarcIa, N; Yan Zang; Ballestar, A; Barzola-Quiquia, J; Bern, F; Esquinazi, P

    2010-01-01

    The electrical potential on the surface of ∼300 nm thick SiO 2 grown on single-crystalline Si substrates has been characterized at ambient conditions using electric field microscopy. Our results show an inhomogeneous potential distribution with fluctuations up to ∼0.4 V within regions of 1 μm. The potential fluctuations observed at the surface of these usual dielectric holders of graphene sheets should induce strong variations in the graphene charge densities and provide a simple explanation for some of the anomalous behaviors of the transport properties of graphene.

  2. Leidenfrost drops cooling surfaces: theory and interferometric measurement

    OpenAIRE

    Van Limbeek, Michiel A. J.; Klein Schaarsberg, Martin H.; Sobac, Benjamin; Rednikov, Alexey; Sun, Chao; Colinet, Pierre; Lohse, Detlef

    2017-01-01

    When a liquid drop is placed on a highly superheated surface, it can be levitated by its own vapour. This remarkable phenomenon is referred to as the Leidenfrost effect. The thermally insulating vapour film results in a severe reduction of the heat transfer rate compared to experiments at lower surface temperatures, where the drop is in direct contact with the solid surface. A commonly made assumption is that this solid surface is isothermal, which is at least questionable for materials of lo...

  3. Measurement of residual radioactive surface contamination by 2-D laser heated TLD

    International Nuclear Information System (INIS)

    Jones, S.C.

    1997-06-01

    The feasibility of applying and adapting a two-dimensional laser heated thermoluminescence dosimetry system to the problem of surveying for radioactive surface contamination was studied. The system consists of a CO 2 laser-based reader and monolithic arrays of thin dosimeter elements. The arrays consist of 10,201 thermoluminescent phosphor elements of 40 micron thickness, covering a 900 cm 2 area. Array substrates are 125 micron thick polyimide sheets, enabling them to easily conform to regular surface shapes, especially for survey of surfaces that are inaccessible for standard survey instruments. The passive, integrating radiation detectors are sensitive to alpha and beta radiation at contamination levels below release guideline limits. Required contact times with potentially contaminated surfaces are under one hour to achieve detection of transuranic alpha emission at 100 dpm/100 cm 2 . Positional information obtained from array evaluation is useful for locating contamination zones. Unique capabilities of this system for survey of sites, facilities and material include measurement inside pipes and other geometrical configurations that prevent standard surveys, and below-surface measurement of alpha and beta emitters in contaminated soils. These applications imply a reduction of material that must be classified as radioactive waste by virtue of its possibility of contamination, and cost savings in soil sampling at contaminated sites

  4. LOGISMOS-B for primates: primate cortical surface reconstruction and thickness measurement

    Science.gov (United States)

    Oguz, Ipek; Styner, Martin; Sanchez, Mar; Shi, Yundi; Sonka, Milan

    2015-03-01

    Cortical thickness and surface area are important morphological measures with implications for many psychiatric and neurological conditions. Automated segmentation and reconstruction of the cortical surface from 3D MRI scans is challenging due to the variable anatomy of the cortex and its highly complex geometry. While many methods exist for this task in the context of the human brain, these methods are typically not readily applicable to the primate brain. We propose an innovative approach based on our recently proposed human cortical reconstruction algorithm, LOGISMOS-B, and the Laplace-based thickness measurement method. Quantitative evaluation of our approach was performed based on a dataset of T1- and T2-weighted MRI scans from 12-month-old macaques where labeling by our anatomical experts was used as independent standard. In this dataset, LOGISMOS-B has an average signed surface error of 0.01 +/- 0.03mm and an unsigned surface error of 0.42 +/- 0.03mm over the whole brain. Excluding the rather problematic temporal pole region further improves unsigned surface distance to 0.34 +/- 0.03mm. This high level of accuracy reached by our algorithm even in this challenging developmental dataset illustrates its robustness and its potential for primate brain studies.

  5. Potentiating the antibacterial effect of silver nanospheres by surface-capping with chlorhexidine gluconate

    Energy Technology Data Exchange (ETDEWEB)

    Priyadarshini, Balasankar Meera; Fawzy, Amr S., E-mail: denasfmf@nus.edu.sg [National University of Singapore, Discipline of Oral Sciences, Faculty of Dentistry (Singapore)

    2017-04-15

    In this work, the commercial polyvinylpyrrolidone (PVP)-capped silver nanospheres (Ag-NSP) were surface decorated with chlorhexidine gluconate (CHXg) for potentiating the antibacterial properties of Ag-NSP. Different formulations of CHXg-loaded Ag-NSP (Ag-NSP/CHXg) were prepared by varying the incubation times (0.5, 1.5, and 3 h). A thorough characterization of Ag-NSP/CHXg nanospheres has been carried out by dynamic light scattering (DLS), transmission electron microscopy (TEM), energy-dispersive surface elemental composition spectral analysis (SEM/EDX), Fourier transform infrared spectroscopy (FTIR), percentage (%) CHXg loading efficiency (LE), in vitro CHXg and Ag{sup +} ion release, antibacterial/biofilm inhibition assay, and human mesenchymal stem cells (hMSCs) cytotoxicity evaluation. DLS measured nanospheres to be <160 nm and indicated that CHXg treatment drastically shifted the surface charge from negative to high positive values, with homogenous distribution. TEM revealed spherical Ag-NSP/CHXg nanospheres with a clearly visible surface coating of CHXg. FTIR confirmed association of CHXg with Ag-NSP nanospheres, whereas SEM/EDX data verified presence of spectral peaks specific to silver (Ag), CHXg, and PVP. The %LE gradually increased with increasing incubation times. In vitro CHXg release exhibited a bi-phasic fashion showing maximum release of ~74.83 ± 20.67% from Ag-NSP/CHXg-3h at 14 days. A slow release of Ag{sup +} ions was detected; however, the surface decoration of Ag-NSP substantially hampered/restricted the liberation of ions. Agar well diffusion, MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl) -2H–tetrazolium), and crystal violet assay suggested good antibacterial/antibiofilm activity of Ag-NSP/CHXg that correlated with the increasing %LE of nanospheres. hMSCs cytotoxicity study showed low toxicity properties of all nanosphere formulations, except for Ag-NSP/CHXg-3h, affecting the cell viability at all

  6. Low-Cost Alternative for the Measurement of Water Levels in Surface Water Streams

    Directory of Open Access Journals (Sweden)

    Luis E. PEÑA

    2017-11-01

    Full Text Available Flood risk management and water resources planning involve a deep knowledge of surface streams so that mitigation strategies and climate change adaptations can be implemented. Commercially, there is a wide range of technologies for the measurement of hydroclimatic variables; however, many of these technologies may not be affordable for institutions with limited budgets. This paper has two main objectives: 1 Present the design of an ultrasound-based water level measurement system, and 2 Propose a methodological alternative for the development of instruments, according to the needs of institutions conducting monitoring of surface waterbodies. To that end, the proposed methodology is based on selection processes defined according to the specific needs of each waterbody. The prototype was tested in real-world scale, with the potential to obtain accurate measurements. Lastly, we present the design of the ultrasound-based water level measurement instrument, which can be built at a low cost. Low-cost instruments can potentially contribute to the sustainable instrumental autonomy of environmental entities and help define measurement and data transmission standards based on the specific requirements of the monitoring.

  7. Experimental measurements of thermoelectric and electrochemical potentials in sandstones saturated with NaCl electrolyte

    Science.gov (United States)

    Leinov, E.; Jackson, M.

    2013-12-01

    evident. Moreover, the contribution of the exclusion potential increases as the permeability of the rock samples decreases. Our results demonstrate that the relative contribution of exclusion and diffusion potentials, expressed in terms of the macroscopic Hittorf transport number, is the same regardless of whether ion transport is in response to temperature or concentration gradients. Hence, it is possible to predict the contribution of TE potentials from EC potential measurements, and vice-versa. Moreover, it is often not valid to ignore the contribution of exclusion potentials, as has been assumed in previous studies; the relative contribution of exclusion and diffusion potentials depends upon the surface charge, the mobility contrast between the co- and counter ions, and the thickness of the electrical double layer relative to the pore-radius, and is predicted reasonably well by the simple model of Westermann-Clark and Christoforou [1986]. Finally, EC and TE potentials may be large in magnitude and make a significant contribution to the measured SP in many natural settings. Westermann-Clark, G.B. and C.C. Christoforou, (1986), The exclusion-diffusion potential in charged porous membranes, J. Electroanal. Chem. 198, 213-231.

  8. Field Measurements of PCB emissions from Building Surfaces Using a New Portable Emission Test Cell

    DEFF Research Database (Denmark)

    Lyng, Nadja; Haven, Rune; Gunnarsen, Lars Bo

    2016-01-01

    The purpose of the study was to measure PCB-emission rates from indoor surfaces on-site in contaminated buildings using a newly developed portable emission test cell. Emission rates were measured from six different surfaces; three untreated surfaces and three remediated surfaces in a contaminated...

  9. Entrance surface dose measurements in pediatric radiological examinations

    International Nuclear Information System (INIS)

    Ribeiro, L.A.; Yoshimura, E.M.

    2008-01-01

    A survey of pediatric radiological examinations was carried out in a reference pediatric hospital of the city of Sao Paulo, in order to investigate the doses to children undergoing conventional X-ray examinations. The results showed that the majority of pediatric patients are below 4 years, and that about 80% of the examinations correspond to chest projections. Doses to typical radiological examinations were measured in vivo with thermoluminescent dosimeters (LiF: Mg, Ti and LiF: Mg, Cu, P) attached to the skin of the children to determine entrance surface dose (ESD). Also homogeneous phantoms were used to obtain ESD to younger children, because the technique uses a so small kVp that the dosimeters would produce an artifact image in the patient radiograph. Four kinds of pediatric examinations were investigated: three conventional examinations (chest, skull and abdomen) and a fluoroscopic procedure (barium swallow). Relevant information about kVp and mAs values used in the examinations was collected, and we discuss how these parameters can affect the ESD. The ESD values measured in this work are compared to reference levels published by the European Commission for pediatric patients. The results obtained (third-quartile of the ESD distribution) for chest AP examinations in three age groups were: 0.056 mGy (2-4 years old); 0.068 mGy (5-9 years old); 0.069 mGy (10-15 years old). All of them are below the European reference level (0.100 mGy). ESD values measured to the older age group in skull and abdomen AP radiographs (mean values 3.44 and 1.20 mGy, respectively) are above the European reference levels (1.5 mGy to skull and 1.0 mGy to abdomen). ESD values measured in the barium swallow examination reached 10 mGy in skin regions corresponding to thyroid and esophagus. It was noticed during this survey that some technicians use, improperly, X-ray fluoroscopy in conventional examinations to help them in positioning the patient. The results presented here are a

  10. Measurements of the streaming potential of clay soils from tropical and subtropical regions using self-made apparatus.

    Science.gov (United States)

    Li, Zhong-Yi; Li, Jiu-Yu; Liu, Yuan; Xu, Ren-Kou

    2014-09-01

    The streaming potential has been wildly used in charged parallel plates, capillaries, and porous media. However, there have been few studies involving the ζ potential of clay soils based on streaming potential measurements. A laboratory apparatus was developed in this study to measure the streaming potential (ΔE) of bulk clay soils' coupling coefficient (C) and cell resistance (R) of saturated granular soil samples. Excellent linearity of ΔE versus liquid pressure (ΔP) ensured the validity of measurements. The obtained parameters of C and R can be used to calculate the ζ potential of bulk soils. The results indicated that the ζ potentials measured by streaming potential method were significantly correlated with the ζ potentials of soil colloids determined by electrophoresis (r (2) = 0.960**). Therefore, the streaming potential method can be used to study the ζ potentials of bulk clay soils. The absolute values of the ζ potentials of four soils followed the order: Ultisol from Jiangxi > Ultisol from Anhui > Oxisol from Guangdong > Oxisol from Hainan, and this was consistent with the cation exchange capacities of these soils. The type and concentration of electrolytes affected soil ζ potentials. The ζ potential became less negative with increased electrolyte concentration. The ζ potentials were more negative in monovalent than in divalent cationic electrolyte solutions because more divalent cations were distributed in the shear plane of the diffuse layer as counter-cations on the soil surfaces than monovalent cations at the same electrolyte concentration.

  11. FJ-2207 measuring instrument detection pipe surface a level of pollution method

    International Nuclear Information System (INIS)

    Wang Jiangong

    2010-01-01

    On the pipe surface contamination were detected α level of pollution is a frequently encountered dose-detection work. Because the pipeline surface arc, while the measuring probe for the plane, which for accurate measurement difficult. In this paper, on the FJ-2207-type pipe surface contamination measuring instrument measuring pollution levels in the α method was studied. Introduced the FJ-2207 measuring instrument detection pipe surface α pollution levels. Studied this measuring instrument on the same sources of surface, plane α level of radioactivity measured differences in the results obtained control of the apparatus when the direct measurement of the surface correction factor, and gives 32-216 specifications commonly used pipe direct measurement of the amendment factor. Convenient method, test results are reliable for the accurate measurement of pipe pollution levels in the surface of α as a reference and learning. (authors)

  12. Effects of drop size and measuring condition on static contact angle measurement on a superhydrophobic surface with goniometric technique

    International Nuclear Information System (INIS)

    Seo, Kwangseok; Kim, Minyoung; Kim, Do Hyun; Ahn, Jeong Keun

    2015-01-01

    It is not a simple task to measure a contact angle of a water drop on a superhydrophobic surface with sessile drop method, because a roll-off angle is very low. Usually contact angle of a water drop on a superhydrophobic surface is measured by fixing a drop with intentional defects on the surface or a needle. We examined the effects of drop size and measuring condition such as the use of a needle or defects on the static contact angle measurement on superhydrophobic surface. Results showed that the contact angles on a superhydrophobic surface remain almost constant within intrinsic measurement errors unless there is a wetting transition during the measurement. We expect that this study will provide a deeper understanding on the nature of the contact angle and convenient measurement of the contact angle on the superhydrophobic surface.

  13. An improved potential drop method for measuring and monitoring defects in metallic structures

    International Nuclear Information System (INIS)

    Oppermann, W.; Keller, H.P.

    1993-01-01

    In the developed form described the direct current potential drop method is a reliable and relatively accurate procedure for the measuring and surveillance of surface cracks in metallic materials. There are also significant possibilities in practice of surveying cracks on the inaccessible side of the structure. The basis for the improvement in accuracy, in particular for short cracks, is firstly an improved measuring technique and secondly calibration curves determined using an electrolytic tank. Practical experience gained in conventional plants is to date positive. The opportunity exists of benefitting from the advantages that would be brought about by an increased use of the potential drop method in plant surveillance. In nuclear plants specifically this would achieve a reduction in the testing personnel's exposure to radiation. (orig.)

  14. Surface temperature measurements on superconducting cavities in superfluid helium

    International Nuclear Information System (INIS)

    Fouaidy, T.; Junquera, T.; Caruette, A.

    1991-01-01

    Two thermometry systems have been developed: a scanning thermometer system routinely used for the 1.5 GHz monocell cavity studies and a fixed thermometer array used to investigate spatial surface resistance distribution on various SC removable endplates of a cylindrical TE011mode cavity. Thermometers used in these systems are thermally insulated from the surrounding HeII bath by an epoxy housing ('epoxy'thermometers). Accurate calibration of the fixed thermometers was conducted by using different test cells and the experimental results were compared to model calculations performed with a finite element computational code. Measured thermometer efficiency and linearity are in good agreement with numerical results. Some typical temperature maps of different Nb samples obtained with the TE011 array (40 epoxy thermometers) are discussed. On the basis of numerical modelling results, a new type of thermometer with an improved efficiency has been designed. The thermal insulation against Helium II has been drastically improved by placing the sensitive part of the thermometer in a small vacuum jacket ('vacuum' thermometers). Two main goals have been reached with the first prototypes: improved efficiency by a factor of 2.5 - 3, and a bath temperature dependence of the thermal response in good agreement with the expected Kapitza conductance behaviour. Fitting experimental results with numerical modelling data, allow us to estimate the Kapitza conductance. The obtained values are in good agreement with the previous results reported by several authors using a different measurement method. The 'vacuum' thermometers are currently used on the TE011 mode cavity with Nb and NbTiN plates and the first results are presented

  15. Crack Growth Monitoring in Harsh Environments by Electric Potential Measurements

    International Nuclear Information System (INIS)

    Lloyd, Wilson Randolph; Reuter, Walter Graham; Weinberg, David Michael

    1999-01-01

    Electric potential measurement (EPM) technology offers an attractive alternative to conventional nondestructive evaluation (NDE) for monitoring crack growth in harsh environments. Where conventional NDE methods typically require localized human interaction, the EPM technique developed at the Idaho National Engineering and Environmental Laboratory (INEEL) can be operated remotely and automatically. Once a crack-like defect is discovered via conventional means, EPM can be applied to monitor local crack size changes. This is of particular interest in situations where an identified structural defect is not immediately rejectable from a fitness-for-service viewpoint, but due to operational and environmental conditions may grow to an unsafe size with continuing operation. If the location is in a harsh environment where periodic monitoring by normal means is either too costly or not possible, a very expensive repair may be immediately mandated. However, the proposed EPM methodology may offer a unique monitoring capability that would allow for continuing service. INEEL has developed this methodology, supporting equipment, and calibration information to apply EPM in a field environment for just this purpose. Laboratory and pilot scale tests on full-size engineering structures (pressure vessels and piping) have been successfully performed. The technique applicable is many severe environments because the sensitive equipment (electronics, operators) can be situated in a remote location, with only current and voltage probe electrical leads entering into the harsh environment. Experimental results showing the utility of the methodology are presented, and unique application concepts that have been examined by multiple experiments are discussed

  16. Electrocardiogram: his bundle potentials can be recorded noninvasively beat by beat on surface electrocardiogram.

    Science.gov (United States)

    Wang, Gaopin; Liu, Renguang; Chang, Qinghua; Xu, Zhaolong; Zhang, Yingjie; Pan, Dianzhu

    2017-03-15

    The micro waveform of His bundle potential can't be recorded beat-to-beat on surface electrocardiogram yet. We have found that the micro-wavelets before QRS complex may be related to atrioventricular conduction system potentials. This study is to explore the possibility of His bundle potential can be noninvasively recorded on surface electrocardiogram. We randomized 65 patients undergoing radiofrequency catheter ablation of paroxysmal superventricular tachycardia (exclude overt Wolff-Parkinson-White syndrome) to receive "conventional electrocardiogram" and "new electrocardiogram" before the procedure. His bundle electrogram was collected during the procedure. Comparative analysis of PA s (PA interval recorded on surface electrocardiogram), AH s (AH interval recorded on surface electrocardiogram) and HV s (HV interval recorded on surface electrocardiogram) interval recorded on surface "new electrocardiogram" and PA, AH, HV interval recorded on His bundle electrogram was investigated. There was no difference (P > 0.05) between groups in HV s interval (49.63 ± 6.19 ms) and HV interval (49.35 ± 6.49 ms). Results of correlational analysis found that HV S interval was significantly positively associated with HV interval (r = 0.929; P electrocardiogram. Noninvasive His bundle potential tracing might represent a new method for locating the site of atrioventricular block and identifying the origin of a wide QRS complex.

  17. Surface Flux Measurements at King Sejong Station in West Antarctica

    Science.gov (United States)

    Choi, T.; Lee, B.; Lee, H.; Shim, J.

    2004-12-01

    The Antarctic Peninsula is important in terms of global warming research due to pronounced increase of air temperature over the last century. The first eddy covariance system was established and turbulent fluxes of heat, water vapor, CO2 and momentum have been measured at King Sejong Station (62 \\deg 13øØS, 58 \\deg 47øØW) located in the northern edge of the Antarctic Peninsula since December in 2002. Our objectives are to better understand the interactions between the Antarctic land surface and the atmosphere and to test the feasibility of the long-term operation of eddy covariance system under extreme weather conditions. Various lichens cover the study area and the dominant species is Usnea fasciata-Himantormia. Based on the analyses on turbulent statistics such as integral turbulence characteristics of vertical velocity (w) and heat (T), stationarity test and investigation of correlation coefficient, they follow the Monin-Obukhov similarity and eddy covariance flux data were reliable. About 50 % of total retrieved sensible heat flux data could be used for further analysis. We will report on seasonal variations of energy and mass fluxes and environmental variables. In addition, factors controlling these fluxes will be presented. Acknowledgement: This study was supported by ¡rEnvironmental Monitoring on Human Impacts at the King Sejong Station, Antarctica¡_ (Project PP04102 of Korea Polar Research Institute) and ¡rEco-technopia 21 project¡_ (Ministry of Environment of Korea).

  18. UAV BASED BRDF-MEASUREMENTS OF AGRICULTURAL SURFACES WITH PFIFFIKUS

    Directory of Open Access Journals (Sweden)

    G. J. Grenzdörffer

    2012-09-01

    Full Text Available BRDF is a common problem in remote sensing and also in oblique photogrammetry. Common approaches of BRDF-measurement with a field goniometer are costly and rather cumbersome. UAVs may offer an interesting alternative by using a special flight pattern of oblique and converging images. The main part of this paper is the description of a photogrammetric workflow in order to determine the anisotropic reflection properties of a given surface. Due to the relatively low flying heights standard procedures from close range photogrammetry were adopted for outdoor usage. The photogrammetric processing delivered automatic and highly accurate orientation information with the aid of coded targets. The interior orientation of the consumer grade camera is more or less stable. The radiometrically corrected oblique images are converted into ortho photos. The azimuth and elevation angle of every point may then be computed. The calculated anisotropy of a winter wheat plot is shown. A system four diagonally-looking cameras (Four Vision and an additional nadir looking camera is under development. The multi camera system especially designed for a Micro- UAV with a payload of min 1 kg. The system is composed of five industrial digital frame cameras (1.3 Mpix CCD-chips, 15 fp/s with fixed lenses. Also special problems with the construction of a light weight housing of the multi camera solution are covered in the paper.

  19. Streaming Potential and Electroosmosis Measurements to Characterize Porous Materials

    NARCIS (Netherlands)

    Luong, D.T.; Sprik, R.

    2013-01-01

    Characterizing the streaming potential and electroosmosis properties of porous media is essential in applying seismoelectric and electroseismic phenomena for oil exploration. Some parameters such as porosity, permeability, formation factor, pore size, the number of pores, and the zeta potential of

  20. Stability of silver nanoparticle monolayers determined by in situ streaming potential measurements

    International Nuclear Information System (INIS)

    Morga, Maria; Adamczyk, Zbigniew; Oćwieja, Magdalena

    2013-01-01

    A silver particle suspension obtained by a chemical reduction was used in this work. Monolayers of these particles (average size 28 nm) on mica modified by poly(allylamine hydrochloride) were produced under diffusion-controlled transport. Monolayer coverages, quantitatively determined by atomic force microscopy (AFM) and SEM, was regulated by adjusting the nanoparticle deposition time and the suspension concentration. The zeta potential of the monolayers was determined by streaming potential measurements carried out under in situ (wet) conditions. These measurements performed for various ionic strengths and pH were interpreted in terms of the three-dimensional (3D) electrokinetic model. The stability of silver monolayers was also investigated using streaming potential and the AFM methods. The decrease in the surface coverage of particles as a function of time and ionic strength varied between 10 −1 and 10 −4  M was investigated. This allowed one to determine the equilibrium adsorption constant K a and the binding energy of silver particles (energy minima depth). Energy minima depth were calculated that varied between −18 kT for I = 10 −1  M and −19 kT for I = 10 −4 for pH 5.5 and T = 298 K. Our investigations suggest that the interactions between surface and nanoparticles are controlled by the electrostatic interactions among ion pairs. It was also shown that the in situ electrokinetic measurements are in accordance with those obtained by more tedious ex situ AFM measurements. This confirmed the utility of the streaming potential method for direct kinetic studies of nanoparticle deposition/release processes.Graphical Abstract

  1. Comparison of Degrees of Potential-Energy-Surface Anharmonicity for Complexes and Clusters with Hydrogen Bonds

    Science.gov (United States)

    Kozlovskaya, E. N.; Doroshenko, I. Yu.; Pogorelov, V. E.; Vaskivskyi, Ye. V.; Pitsevich, G. A.

    2018-01-01

    Previously calculated multidimensional potential-energy surfaces of the MeOH monomer and dimer, water dimer, malonaldehyde, formic acid dimer, free pyridine-N-oxide/trichloroacetic acid complex, and protonated water dimer were analyzed. The corresponding harmonic potential-energy surfaces near the global minima were constructed for series of clusters and complexes with hydrogen bonds of different strengths based on the behavior of the calculated multidimensional potential-energy surfaces. This enabled the introduction of an obvious anharmonicity parameter for the calculated potential-energy surfaces. The anharmonicity parameter was analyzed as functions of the size of the analyzed area near the energy minimum, the number of points over which energies were compared, and the dimensionality of the solved vibrational problem. Anharmonicity parameters for potential-energy surfaces in complexes with strong, medium, and weak H-bonds were calculated under identical conditions. The obtained anharmonicity parameters were compared with the corresponding diagonal anharmonicity constants for stretching vibrations of the bridging protons and the lengths of the hydrogen bridges.

  2. An Analytical Model of Nanometer Scale Viscoelastic Properties of Polymer Surfaces Measured Using an Atomic Force Microscope

    Science.gov (United States)

    2011-03-01

    have been developed ranging from measuring surface details to modifying surface structures . This chapter focuses on aspects of AFM modeling the- ory and...how far apart they are. An example of a poten- tial function is the Lennard-Jones potential, which is also called the 6-12 potential. It can be...γ1 + γ2 + γ12, (31) where γ1 and γ2 are the surface energies of the two adhering spheres, and γ12 is the interfacial energy between the two spheres

  3. Monophasic action potentials and activation recovery intervals as measures of ventricular action potential duration: experimental evidence to resolve some controversies

    NARCIS (Netherlands)

    Coronel, Ruben; de Bakker, Jacques M. T.; Wilms-Schopman, Francien J. G.; Opthof, Tobias; Linnenbank, André C.; Belterman, Charly N.; Janse, Michiel J.

    2006-01-01

    BACKGROUND: Activation recovery intervals (ARIs) and monophasic action potential (MAP) duration are used as measures of action potential duration in beating hearts. However, controversies exist concerning the correct way to record MAPs or calculate ARIs. We have addressed these issues

  4. The sea surface currents as a potential factor in the estimation and monitoring of wave energy potential

    Science.gov (United States)

    Zodiatis, George; Galanis, George; Nikolaidis, Andreas; Stylianoy, Stavros; Liakatas, Aristotelis

    2015-04-01

    The use of wave energy as an alternative renewable is receiving attention the last years under the shadow of the economic crisis in Europe and in the light of the promising corresponding potential especially for countries with extended coastline. Monitoring and studying the corresponding resources is further supported by a number of critical advantages of wave energy compared to other renewable forms, like the reduced variability and the easier adaptation to the general grid, especially when is jointly approached with wind power. Within the framework, a number of countries worldwide have launched research and development projects and a significant number of corresponding studies have been presented the last decades. However, in most of them the impact of wave-sea surface currents interaction on the wave energy potential has not been taken into account neglecting in this way a factor of potential importance. The present work aims at filling this gap for a sea area with increased scientific and economic interest, the Eastern Mediterranean Sea. Based on a combination of high resolution numerical modeling approach with advanced statistical tools, a detailed analysis is proposed for the quantification of the impact of sea surface currents, which produced from downscaling the MyOcean-FO regional data, to wave energy potential. The results although spatially sensitive, as expected, prove beyond any doubt that the wave- sea surface currents interaction should be taken into account for similar resource analysis and site selection approaches since the percentage of impact to the available wave power may reach or even exceed 20% at selected areas.

  5. Evaluation of ATP measurements to detect microbial ingress by wastewater and surface water in drinking water.

    Science.gov (United States)

    Vang, Óluva K; Corfitzen, Charlotte B; Smith, Christian; Albrechtsen, Hans-Jørgen

    2014-11-01

    Fast and reliable methods are required for monitoring of microbial drinking water quality in order to protect public health. Adenosine triphosphate (ATP) was investigated as a potential real-time parameter for detecting microbial ingress in drinking water contaminated with wastewater or surface water. To investigate the ability of the ATP assay in detecting different contamination types, the contaminant was diluted with non-chlorinated drinking water. Wastewater, diluted at 10(4) in drinking water, was detected with the ATP assay, as well as 10(2) to 10(3) times diluted surface water. To improve the performance of the ATP assay in detecting microbial ingress in drinking water, different approaches were investigated, i.e. quantifying microbial ATP or applying reagents of different sensitivities to reduce measurement variations; however, none of these approaches contributed significantly in this respect. Compared to traditional microbiological methods, the ATP assay could detect wastewater and surface water in drinking water to a higher degree than total direct counts (TDCs), while both heterotrophic plate counts (HPC 22 °C and HPC 37 °C) and Colilert-18 (Escherichia coli and coliforms) were more sensitive than the ATP measurements, though with much longer response times. Continuous sampling combined with ATP measurements displays definite monitoring potential for microbial drinking water quality, since microbial ingress in drinking water can be detected in real-time with ATP measurements. The ability of the ATP assay to detect microbial ingress is influenced by both the ATP load from the contaminant itself and the ATP concentration in the specific drinking water. Consequently, a low ATP concentration of the specific drinking water facilitates a better detection of a potential contamination of the water supply with the ATP assay. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. On the measurement of the surface energy budget over a land ...

    Indian Academy of Sciences (India)

    The measurement of surface energy balance over a land surface in an open area in Bangalore is reported. Measurements of all variables needed to calculate the surface energy balance on time scales longer than a week are made. Components of radiative fluxes are measured while sensible and latent heat fluxes are ...

  7. Land surface temperature as potential indicator of burn severity in forest Mediterranean ecosystems

    Science.gov (United States)

    Quintano, C.; Fernández-Manso, A.; Calvo, L.; Marcos, E.; Valbuena, L.

    2015-04-01

    Forest fires are one of the most important causes of environmental alteration in Mediterranean countries. Discrimination of different degrees of burn severity is critical for improving management of fire-affected areas. This paper aims to evaluate the usefulness of land surface temperature (LST) as potential indicator of burn severity. We used a large convention-dominated wildfire, which occurred on 19-21 September, 2012 in Northwestern Spain. From this area, a 1-year series of six LST images were generated from Landsat 7 Enhanced Thematic Mapper (ETM+) data using a single channel algorithm. Further, the Composite Burn Index (CBI) was measured in 111 field plots to identify the burn severity level (low, moderate, and high). Evaluation of the potential relationship between post-fire LST and ground measured CBI was performed by both correlation analysis and regression models. Correlation coefficients were higher in the immediate post-fire LST images, but decreased during the fall of 2012 and increased again with a second maximum value in summer, 2013. A linear regression model between post-fire LST and CBI allowed us to represent spatially predicted CBI (R-squaredadj > 85%). After performing an analysis of variance (ANOVA) between post-fire LST and CBI, a Fisher's least significant difference test determined that two burn severity levels (low-moderate and high) could be statistically distinguished. The identification of such burn severity levels is sufficient and useful to forest managers. We conclude that summer post-fire LST from moderate resolution satellite data may be considered as a valuable indicator of burn severity for large fires in Mediterranean forest ecosytems.

  8. Self-consistent density functional calculation of the image potential at a metal surface

    International Nuclear Information System (INIS)

    Jung, J; Alvarellos, J E; Chacon, E; GarcIa-Gonzalez, P

    2007-01-01

    It is well known that the exchange-correlation (XC) potential at a metal surface has an image-like asymptotic behaviour given by -1/4(z-z 0 ), where z is the coordinate perpendicular to the surface. Using a suitable fully non-local functional prescription, we evaluate self-consistently the XC potential with the correct image behaviour for simple jellium surfaces in the range of metallic densities. This allows a proper comparison between the corresponding image-plane position, z 0 , and other related quantities such as the centroid of an induced charge by an external perturbation. As a by-product, we assess the routinely used local density approximation when evaluating electron density profiles, work functions, and surface energies by focusing on the XC effects included in the fully non-local description

  9. Self-consistent density functional calculation of the image potential at a metal surface

    Energy Technology Data Exchange (ETDEWEB)

    Jung, J [Departamento de Fisica Fundamental, Universidad Nacional de Educacion a Distancia, Apartado 60141, 28080 Madrid (Spain); Alvarellos, J E [Departamento de Fisica Fundamental, Universidad Nacional de Educacion a Distancia, Apartado 60141, 28080 Madrid (Spain); Chacon, E [Instituto de Ciencias de Materiales de Madrid, Consejo Superior de Investigaciones CientIficas, E-28049 Madrid (Spain); GarcIa-Gonzalez, P [Departamento de Fisica Fundamental, Universidad Nacional de Educacion a Distancia, Apartado 60141, 28080 Madrid (Spain)

    2007-07-04

    It is well known that the exchange-correlation (XC) potential at a metal surface has an image-like asymptotic behaviour given by -1/4(z-z{sub 0}), where z is the coordinate perpendicular to the surface. Using a suitable fully non-local functional prescription, we evaluate self-consistently the XC potential with the correct image behaviour for simple jellium surfaces in the range of metallic densities. This allows a proper comparison between the corresponding image-plane position, z{sub 0}, and other related quantities such as the centroid of an induced charge by an external perturbation. As a by-product, we assess the routinely used local density approximation when evaluating electron density profiles, work functions, and surface energies by focusing on the XC effects included in the fully non-local description.

  10. Modeling Solar-Wind Heavy-Ions' Potential Sputtering of Lunar KREEP Surface

    Science.gov (United States)

    Barghouty, A. F.; Meyer, F. W.; Harris, R. P.; Adams, J. H., Jr.

    2012-01-01

    Recent laboratory data suggest that potential sputtering may be an important weathering mechanism that can affect the composition of both the lunar surface and its tenuous exosphere; its role and implications, however, remain unclear. Using a relatively simple kinetic model, we will demonstrate that solar-wind heavy ions induced sputtering of KREEP surfaces is critical in establishing the timescale of the overall solar-wind sputtering process of the lunar surface. We will also also show that potential sputtering leads to a more pronounced and significant differentiation between depleted and enriched surface elements. We briefly discuss the impacts of enhanced sputtering on the composition of the regolith and the exosphere, as well as of solar-wind sputtering as a source of hydrogen and water on the moon.

  11. High volume hydraulic fracturing operations: potential impacts on surface water and human health.

    Science.gov (United States)

    Mrdjen, Igor; Lee, Jiyoung

    2016-08-01

    High volume, hydraulic fracturing (HVHF) processes, used to extract natural gas and oil from underground shale deposits, pose many potential hazards to the environment and human health. HVHF can negatively affect the environment by contaminating soil, water, and air matrices with potential pollutants. Due to the relatively novel nature of the process, hazards to surface waters and human health are not well known. The purpose of this article is to link the impacts of HVHF operations on surface water integrity, with human health consequences. Surface water contamination risks include: increased structural failure rates of unconventional wells, issues with wastewater treatment, and accidental discharge of contaminated fluids. Human health risks associated with exposure to surface water contaminated with HVHF chemicals include increased cancer risk and turbidity of water, leading to increased pathogen survival time. Future research should focus on modeling contamination spread throughout the environment, and minimizing occupational exposure to harmful chemicals.

  12. Reconstruction of the Tip-Surface Interaction Potential by Analysis of the Brownian Motion of an Atomic Force Microscope Tip

    NARCIS (Netherlands)

    Willemsen, O.H.; Kuipers, L.; van der Werf, Kees; de Grooth, B.G.; Greve, Jan

    2000-01-01

    The thermal movement of an atomic force microscope (AFM) tip is used to reconstruct the tip-surface interaction potential. If a tip is brought into the vicinity of a surface, its movement is governed by the sum of the harmonic cantilever potential and the tip-surface interaction potential. By

  13. MRD-CI potential surfaces using balanced basis sets. IV. The H2 molecule and the H3 surface

    International Nuclear Information System (INIS)

    Wright, J.S.; Kruus, E.

    1986-01-01

    The utility of midbond functions in molecular calculations was tested in two cases where the correct results are known: the H 2 potential curve and the collinear H 3 potential surface. For H 2 , a variety of basis sets both with and without bond functions was compared to the exact nonrelativistic potential curve of Kolos and Wolniewicz [J. Chem. Phys. 43, 2429 (1965)]. It was found that optimally balanced basis sets at two levels of quality were the double zeta single polarization plus sp bond function basis (BF1) and the triple zeta double polarization plus two sets of sp bond function basis (BF2). These gave bond dissociation energies D/sub e/ = 4.7341 and 4.7368 eV, respectively (expt. 4.7477 eV). Four basis sets were tested for basis set superposition errors, which were found to be small relative to basis set incompleteness and therefore did not affect any conclusions regarding basis set balance. Basis sets BF1 and BF2 were used to construct potential surfaces for collinear H 3 , along with the corresponding basis sets DZ*P and TZ*PP which contain no bond functions. Barrier heights of 12.52, 10.37, 10.06, and 9.96 kcal/mol were obtained for basis sets DZ*P, TZ*PP, BF1, and BF2, respectively, compared to an estimated limiting value of 9.60 kcal/mol. Difference maps, force constants, and relative rms deviations show that the bond functions improve the surface shape as well as the barrier height

  14. Interface bonding in silicon oxide nanocontacts: interaction potentials and force measurements

    Science.gov (United States)

    Wierez-Kien, M.; Craciun, A. D.; Pinon, A. V.; Le Roux, S.; Gallani, J. L.; Rastei, M. V.

    2018-04-01

    The interface bonding between two silicon-oxide nanoscale surfaces has been studied as a function of atomic nature and size of contacting asperities. The binding forces obtained using various interaction potentials are compared with experimental force curves measured in vacuum with an atomic force microscope. In the limit of small nanocontacts (typically contact area which is altered by stretching speeds. The mean unbinding force is found to decrease as the contact spends time in the attractive regime. This contact weakening is featured by a negative aging coefficient which broadens and shifts the thermal-induced force distribution at low stretching speeds.

  15. Technical Note: Out-of-field dose measurement at near surface with plastic scintillator detector.

    Science.gov (United States)

    Bourgouin, Alexandra; Varfalvy, Nicolas; Archambault, Louis

    2016-09-08

    Out-of-field dose depends on multiple factors, making peripheral dosimetry com-plex. Only a few dosimeters have the required features for measuring peripheral dose. Plastic scintillator dosimeters (PSDs) offer numerous dosimetric advantages as required for out-of-field dosimetry. The purpose of this study is to determine the potential of using PSD as a surface peripheral dosimeter. Measurements were performed with a parallel-plate ion chamber, a small volume ion chamber, and with a PSD. Lateral-dose measurements (LDM) at 0.5 cm depth and depth-dose curve (PDD) were made and compared to the dose calculation provided by a treatment planning system (TPS). This study shows that a PSD can measure a dose as low as 0.51 ± 0.17 cGy for photon beam and 0.58 ± 0.20 cGy for electron beam with a difference of 0.2 and 0.1 cGy compared to a parallel-plate ion chamber. This study demonstrates the potential of using PSD as an out-of-field dosimeter since measure-ments with PSD avoid averaging over a too-large depth, at 1 mm diameter, and can make precise measurement at very low dose. Also, electronic equilibrium is easier to reach with PSD due to its small sensitive volume and its water equivalence. © 2016 The Authors.

  16. Permutation invariant potential energy surfaces for polyatomic reactions using atomistic neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Kolb, Brian [Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Zhao, Bin; Guo, Hua, E-mail: hguo@unm.edu [Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Li, Jun [School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331 (China); Jiang, Bin [Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2016-06-14

    The applicability and accuracy of the Behler-Parrinello atomistic neural network method for fitting reactive potential energy surfaces is critically examined in three systems, H + H{sub 2} → H{sub 2} + H, H + H{sub 2}O → H{sub 2} + OH, and H + CH{sub 4} → H{sub 2} + CH{sub 3}. A pragmatic Monte Carlo method is proposed to make efficient choice of the atom-centered mapping functions. The accuracy of the potential energy surfaces is not only tested by fitting errors but also validated by direct comparison in dynamically important regions and by quantum scattering calculations. Our results suggest this method is both accurate and efficient in representing multidimensional potential energy surfaces even when dissociation continua are involved.

  17. Permutation invariant potential energy surfaces for polyatomic reactions using atomistic neural networks

    International Nuclear Information System (INIS)

    Kolb, Brian; Zhao, Bin; Guo, Hua; Li, Jun; Jiang, Bin

    2016-01-01

    The applicability and accuracy of the Behler-Parrinello atomistic neural network method for fitting reactive potential energy surfaces is critically examined in three systems, H + H 2 → H 2 + H, H + H 2 O → H 2 + OH, and H + CH 4 → H 2 + CH 3 . A pragmatic Monte Carlo method is proposed to make efficient choice of the atom-centered mapping functions. The accuracy of the potential energy surfaces is not only tested by fitting errors but also validated by direct comparison in dynamically important regions and by quantum scattering calculations. Our results suggest this method is both accurate and efficient in representing multidimensional potential energy surfaces even when dissociation continua are involved.

  18. Investigation of human body potential measured by a non-contact measuring system.

    Science.gov (United States)

    Ichikawa, Norimitsu

    2016-12-07

    A human body is occasionally electrified in a room. This charged object will be a source of electrostatic accidents, including the malfunction of electronic equipment. Hence, prevention of these accidents is required. Accidents occasionally occur, even though antistatic clothes and shoes are used. One of the causes for these accidents is that there is a lack of the preventive measures. This situation occurs when using, for example, unconductive wax. In this study, human body potential (voltage) is measured using a non-contact measuring system. An investigation of the human body's voltage when using this system is conducted. The result demonstrates that the voltage of a human body wearing antistatic clothes and shoes or light clothes and slippers exceeds a malfunctioning voltage of a microelectronics device when the body walks on floors. Thus, accidents may occur even if a human body wearing the antistatic clothes walks on flooring. These results will be useful in estimating determination whether electrostatic accidents occur or not.

  19. Biofilm formation by Listeria monocytogenes on stainless steel surface and biotransfer potential

    OpenAIRE

    Oliveira,Maíra Maciel Mattos de; Brugnera,Danilo Florisvaldo; Alves,Eduardo; Piccoli,Roberta Hilsdorf

    2010-01-01

    An experimental model was proposed to study biofilm formation by Listeria monocytogenes ATCC 19117 on AISI 304 (#4) stainless steel surface and biotransfer potential during this process. In this model, biofilm formation was conducted on the surface of stainless steel coupons, set on a stainless steel base with 4 divisions, each one supporting 21 coupons. Trypic Soy Broth was used as bacterial growth substrate, with incubation at 37 ?C and stirring of 50 rpm. The number of adhered cells was de...

  20. Near-surface geothermal potential assessment of the region Leogang - Saalbach-Hinterglemm in Salzburg, Austria

    Science.gov (United States)

    Bottig, Magdalena; Rupprecht, Doris; Hoyer, Stefan

    2017-04-01

    Within the EU-funded Alpine Space project GRETA (Near-surface Geothermal Resources in the Territory of the Alpine space), a potential assessment for the use of near-surface geothermal energy is being performed. The focus region for Austria is represented by the two communities Leogang and Saalbach-Hinterglemm where settlements are located in altitudes of about 800 - 1.000 m. In these communities, as well as in large parts of the alpine space region in Austria, winter sports tourism is an important economic factor. The demand for heating and domestic hot water in this region of about 6.000 inhabitants rises significantly in the winter months due to around 2 million guest nights per year. This makes clear why the focus is on touristic infrastructure like alpine huts or hotels. It is a high-altitude area with a large number of remote houses, thus district-heating is not ubiquitous - thus, near-surface geothermal energy can be a useful solution for a self-sufficient energy supply. The objective of detailed investigation within the project is, to which extent the elevation, the gradient and the orientation of the hillside influence the geothermal usability of the shallow underground. To predict temperatures in depths of up to 100 m and therefore make statements on the geothermal usability of a certain piece of land, it is necessary to attain a precise ground-temperature map which reflects the upper model boundary. As there are no ground temperature measurement stations within the region, the GBA has installed four monitoring stations. Two are located in the valley, at altitudes of about 800 m, and two in higher altitudes of about 1.200 m, one on a south- and one on a north-slope. Using a software invented by the University of Soil Sciences in Vienna a ground-temperature map will be calculated. The calculation is based on climatic data considering parameters like soil composition. Measured values from the installed monitoring stations will help to validate or to

  1. Potential-induced structural transitions of DL-homocysteine monolayers on Au(111) electrode surfaces

    DEFF Research Database (Denmark)

    Zhang, Jingdong; Demetriou, Anna; Welinder, Anne Christina

    2005-01-01

    Monolayers of homocysteine on Au(111)-surfaces have been investigated by voltammetry, in situ scanning tunnelling microscopy (STM) and subtractively normalised interfacial Fourier transform spectroscopy (SNIFTIRS). A pair of sharp voltammetric peaks build up in the potential range 0 to -0.1 V (vs...... potentials at pH 7.7. The molecules pack into highly ordered domains around the peak potential. High-resolution in situ STM reveals a (root 3 x 5) R30 degrees lattice with three homocysteine molecules in each unit cell. The adlayer changes into disordered structures on either side of the peak potential...

  2. Potential of near-surface geothermal heat - Experiences from the planning practice; Potential der oberflaechennahen Geothermie. Erfahrungen aus der Planungspraxis

    Energy Technology Data Exchange (ETDEWEB)

    Kuebert, Markus; Kuntz, David; Walker-Hertkorn, Simone [systherma GmbH, Planungsbuero fuer Erdwaermesysteme, Starzach-Felldorf (Germany)

    2010-07-01

    Near-surface geothermal applications as a heat source for ground source heat pump systems are an approved energy source in the area of residential buildings. Within the commercial range, the near-surface geothermal energy also can supply coldness in order to cool buildings. In the contribution under consideration, a flow chart of a geothermal project is presented by examining the feasibility up to the acceptance of work. With this approach it is possible to exhaust optimally the geothermal potential at a location including the trades and planners involved. In particular, the significance of the preliminary design for the entire later smooth course of the project is to be stated. Practical examples for possible operational areas of the geothermal energy and to their borders are described.

  3. MEASURING PROTOPLANETARY DISK GAS SURFACE DENSITY PROFILES WITH ALMA

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Jonathan P.; McPartland, Conor, E-mail: jpw@ifa.hawaii.edu [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)

    2016-10-10

    The gas and dust are spatially segregated in protoplanetary disks due to the vertical settling and radial drift of large grains. A fuller accounting of the mass content and distribution in disks therefore requires spectral line observations. We extend the modeling approach presented in Williams and Best to show that gas surface density profiles can be measured from high fidelity {sup 13}CO integrated intensity images. We demonstrate the methodology by fitting ALMA observations of the HD 163296 disk to determine a gas mass, M {sub gas} = 0.048 M {sub ⊙}, and accretion disk characteristic size R {sub c} = 213 au and gradient γ = 0.39. The same parameters match the C{sup 18}O 2–1 image and indicate an abundance ratio [{sup 12}CO]/[C{sup 18}O] of 700 independent of radius. To test how well this methodology can be applied to future line surveys of smaller, lower mass T Tauri disks, we create a large {sup 13}CO 2–1 image library and fit simulated data. For disks with gas masses 3–10 M {sub Jup} at 150 pc, ALMA observations with a resolution of 0.″2–0.″3 and integration times of ∼20 minutes allow reliable estimates of R {sub c} to within about 10 au and γ to within about 0.2. Economic gas imaging surveys are therefore feasible and offer the opportunity to open up a new dimension for studying disk structure and its evolution toward planet formation.

  4. Theoretical and practical aspects of measuring market potential

    Directory of Open Access Journals (Sweden)

    Bešlagić Mirza

    2016-01-01

    Full Text Available The area of research in this paper refers to the theoretical, practical and methodological aspects of the assessment of market potential. It presents the main factors relevant to assessing market potential. The process of evaluating the market potential is important, first of all, for optimal adoption of future strategic decisions in business. Planning of business processes is one of the main reasons for the assessment of the market potential and managers often face, when planning, the environmental factors that can not be influenced. Realistic and quality assessment of market potential and sales forecasting in companies becomes not only a means of gaining competitive advantage, but also a necessary condition for long-term development and survival in the market. Knowledge of the potential market increases the efficiency of business operations. To this end, the theoretical, methodological and practical problems of assessment of market potential were analyzed. The need for this is all the more pronounced because of objective, reliable and valid assessment of the market potential is a prerequisite of business improvement and long-term development of enterprises. The aim was to explain the characteristics of the market potential as one of the primary market sizes in order to carry out its assessment. In this context, it was necessary to identify the main factors influencing the assessment of market potential. Results of the study showed that factors of macro and micro environment of the company, competition and purchasing power determine the market potential of edible oil in Bosnia and Herzegovina. In the empirical part of the paper are applied most common methods of assessment of market potential.

  5. Fluorescence quenching studies of potential-dependent DNA reorientation dynamics at glassy carbon electrode surfaces.

    Science.gov (United States)

    Li, Qin; Cui, Chenchen; Higgins, Daniel A; Li, Jun

    2012-09-05

    The potential-dependent reorientation dynamics of double-stranded DNA (ds-DNA) attached to planar glassy carbon electrode (GCE) surfaces were investigated. The orientation state of surface-bound ds-DNA was followed by monitoring the fluorescence from a 6-carboxyfluorescein (FAM6) fluorophore covalently linked to the distal end of the DNA. Positive potentials (i.e., +0.2 V vs open circuit potential, OCP) caused the ds-DNA to align parallel to the electrode surface, resulting in strong dipole-electrode quenching of FAM6 fluorescence. Switching of the GCE potential to negative values (i.e., -0.2 V vs OCP) caused the ds-DNA to reorient perpendicular to the electrode surface, with a concomitant increase in FAM6 fluorescence. In addition to the very fast (submilliseconds) dynamics of the initial reorientation process, slow (0.1-0.9 s) relaxation of FAM6 fluorescence to intermediate levels was also observed after potential switching. These dynamics have not been previously described in the literature. They are too slow to be explained by double layer charging, and chronoamperometry data showed no evidence of such effects. Both the amplitude and rate of the dynamics were found to depend upon buffer concentration, and ds-DNA length, demonstrating a dependence on the double layer field. The dynamics are concluded to arise from previously undetected complexities in the mechanism of potential-dependent ds-DNA reorientation. The possible origins of these dynamics are discussed. A better understanding of these dynamics will lead to improved models for potential-dependent ds-DNA reorientation at electrode surfaces and will facilitate the development of advanced electrochemical devices for detection of target DNAs.

  6. Calculation of high-dimensional fission-fusion potential-energy surfaces in the SHE region

    International Nuclear Information System (INIS)

    Moeller, Peter; Sierk, Arnold J.; Ichikawa, Takatoshi; Iwamoto, Akira

    2004-01-01

    We calculate in a macroscopic-microscopic model fission-fusion potential-energy surfaces relevant to the analysis of heavy-ion reactions employed to form heavy-element evaporation residues. We study these multidimensional potential-energy surfaces both inside and outside the touching point.Inside the point of contact we define the potential on a multi-million-point grid in 5D deformation space where elongation, merging projectile and target spheroidal shapes, neck radius and projectile/target mass asymmetry are independent shape variables. The same deformation space and the corresponding potential-energy surface also describe the shape evolution from the nuclear ground-state to separating fragments in fission, and the fast-fission trajectories in incomplete fusion.For separated nuclei we study the macroscopic-microscopic potential energy, that is the ''collision surface'' between a spheroidally deformed target and a spheroidally deformed projectile as a function of three coordinates which are: the relative location of the projectile center-of-mass with respect to the target center-of-mass and the spheroidal deformations of the target and the projectile. We limit our study to the most favorable relative positions of target and projectile, namely that the symmetry axes of the target and projectile are collinear

  7. Potential Denitrification: Concept and Conditions of its Measurement ...

    African Journals Online (AJOL)

    Denitrification plays important roles in nitrogen cycling and management affecting both the environment and agricultural systems. Potential denitrification has a role in comparison of denitrification magnitudes in different soils. This paper discusses the concept of potential denitrification in relation to denitrification rate and ...

  8. Edge effects in four-point direct current potential drop measurements on metal plates

    International Nuclear Information System (INIS)

    Lu, Y; Bowler, N; Bowler, J R; Huang, Y

    2009-01-01

    Four-point direct current potential drop (DCPD) measurements are commonly used to measure the conductivity (or resistivity) of semiconductors and ferrous or non-ferrous metals. The measured electrical potential difference is often interpreted in terms of analytic expressions developed for large plates that are either 'thin' or 'thick' relative to the probe length. It is well known that the presence of the back surface of a plate leads to a solution expressed in terms of an infinite series representing the current source and its images. This approach can be generalized to account for multiple surfaces in order to obtain a solution for a finite plate, but convergence of the series is poor when the plate dimensions are similar to or smaller than the separation of the current injection and extraction points. Here, Fourier series representations of the infinite sums are obtained. It is shown that the Fourier series converge with many fewer terms than the series obtained from image theory, for plates with dimensions similar to or smaller than the separation of the current injection and extraction points. Comparing calculated results for the potential drop obtained by a four-point probe centred on finite plates of varying dimension, with those for a probe in contact with a large (laterally infinite) plate, estimates are given of the uncertainty due to edge effects in measurements on small plates interpreted using analytic formulae developed for large plates. It is also shown that these uncertainties due to edge effects are reduced, for a given plate size, if the probe pick-up points are moved closer to the current injection points, rather than adopting the common arrangement in which the four probe points are equally spaced. Calculated values of DCPD are compared with experimental data taken on aluminium and spring-steel plates of various sizes and excellent agreement is obtained.

  9. Edge effects in four-point direct current potential drop measurements on metal plates

    Science.gov (United States)

    Lu, Y.; Bowler, N.; Bowler, J. R.; Huang, Y.

    2009-07-01

    Four-point direct current potential drop (DCPD) measurements are commonly used to measure the conductivity (or resistivity) of semiconductors and ferrous or non-ferrous metals. The measured electrical potential difference is often interpreted in terms of analytic expressions developed for large plates that are either 'thin' or 'thick' relative to the probe length. It is well known that the presence of the back surface of a plate leads to a solution expressed in terms of an infinite series representing the current source and its images. This approach can be generalized to account for multiple surfaces in order to obtain a solution for a finite plate, but convergence of the series is poor when the plate dimensions are similar to or smaller than the separation of the current injection and extraction points. Here, Fourier series representations of the infinite sums are obtained. It is shown that the Fourier series converge with many fewer terms than the series obtained from image theory, for plates with dimensions similar to or smaller than the separation of the current injection and extraction points. Comparing calculated results for the potential drop obtained by a four-point probe centred on finite plates of varying dimension, with those for a probe in contact with a large (laterally infinite) plate, estimates are given of the uncertainty due to edge effects in measurements on small plates interpreted using analytic formulae developed for large plates. It is also shown that these uncertainties due to edge effects are reduced, for a given plate size, if the probe pick-up points are moved closer to the current injection points, rather than adopting the common arrangement in which the four probe points are equally spaced. Calculated values of DCPD are compared with experimental data taken on aluminium and spring-steel plates of various sizes and excellent agreement is obtained.

  10. Which potentials have to be surface peaked to reproduce large angle proton scattering at high energy?

    International Nuclear Information System (INIS)

    Raynal, J.

    1990-01-01

    Corrections to the usual form factors of the optical potential are studied with a view to getting a better fit for proton elastic scattering at large angles on 40 Ca at 497 and 800 MeV. When a real surface form factor is added to the central potential in the Schrodinger formalism, the experimental data are as well reproduced as in the standard Dirac formalism. Coupling to the strong 3 - collective state gives a better fit. The use of surface corrections to the imaginary Dirac potential also gives improved results. A slightly better fit is obtained by coupling to the 3 - state with, at the same time, a weakening of these corrections. Further corrections to the potential do not give significant improvements

  11. Spatial potential ripples of azimuthal surface modes in topological insulator Bi2Te3 nanowires.

    Science.gov (United States)

    Muñoz Rojo, Miguel; Zhang, Yingjie; Manzano, Cristina V; Alvaro, Raquel; Gooth, Johannes; Salmeron, Miquel; Martin-Gonzalez, Marisol

    2016-01-11

    Topological insulators (TI) nanowires (NW) are an emerging class of structures, promising both novel quantum effects and potential applications in low-power electronics, thermoelectrics and spintronics. However, investigating the electronic states of TI NWs is complicated, due to their small lateral size, especially at room temperature. Here, we perform scanning probe based nanoscale imaging to resolve the local surface potential landscapes of Bi2Te3 nanowires (NWs) at 300 K. We found equipotential rings around the NWs perimeter that we attribute to azimuthal 1D modes. Along the NW axis, these modes are altered, forming potential ripples in the local density of states, due to intrinsic disturbances. Potential mapping of electrically biased NWs enabled us to accurately determine their conductivity which was found to increase with the decrease of NW diameter, consistent with surface dominated transport. Our results demonstrate that TI NWs can pave the way to both exotic quantum states and novel electronic devices.

  12. Influence of Surface Charge/Potential of a Gold Electrode on the Adsorptive/Desorptive Behaviour of Fibrinogen

    International Nuclear Information System (INIS)

    Dargahi, Mahdi; Konkov, Evgeny; Omanovic, Sasha

    2015-01-01

    . It was suggested that the driving force for the adsorption of FG on a negatively charged surface represents a positive gain in the entropy of the system, whereas the adsorption on a positively charged gold surface was found to be controlled by electrostatic forces. FG desorption measurements revealed that when the gold surface is polarized within the electrochemical double-layer region during the desorption process, the protein desorption kinetics is rather slow. However, within the regions of hydrogen and oxygen evolution, the FG desorption kinetics accelerates significantly, due to the physical removal of the adsorbed protein layer by gas bubbles evolving from the substrate surface, which enables a complete removal of the pre-adsorbed FG layer. The latter could potentially be employed for electrochemical cleaning of electrically-conducting surfaces fouled by adsorbed protein layers (heat exchangers, filtration membranes, etc.)

  13. Toward accurate prediction of potential energy surfaces and the spectral density of hydrogen bonded systems

    International Nuclear Information System (INIS)

    Rekik, Najeh

    2014-01-01

    Despite the considerable progress made in quantum theory and computational methods, detailed descriptions of the potential energy surfaces of hydrogen-bonded systems have not yet been achieved. In addition, the hydrogen bond (H-bond) itself is still so poorly understood at the fundamental level that it remains unclear exactly what geometry constitutes a “real” H-bond. Therefore, in order to investigate features essential for hydrogen bonded complexes, a simple, efficient, and general method for calculating matrix elements of vibrational operators capable of describing the stretching modes and the H-bond bridges of hydrogen-bonded systems is proposed. The derived matrix elements are simple and computationally easy to evaluate, which makes the method suitable for vibrational studies of multiple-well potentials. The method is illustrated by obtaining potential energy surfaces for a number of two-dimensional systems with repulsive potentials chosen to be in Gaussian form for the stretching mode and of the Morse-type for the H-bond bridge dynamics. The forms of potential energy surfaces of weak and strong hydrogen bonds are analyzed by varying the asymmetry of the Gaussian potential. Moreover, the choice and applicability of the selected potential for the stretching mode and comparison with other potentials used in the area of hydrogen bond research are discussed. The approach for the determination of spectral density has been constructed in the framework of the linear response theory for which spectral density is obtained by Fourier transform of the autocorrelation function of the dipole moment operator of the fast mode. The approach involves anharmonic coupling between the high frequency stretching vibration (double well potential) and low-frequency donor-acceptor stretching mode (Morse potential) as well as the electrical anharmonicity of the dipole moment operator of the fast mode. A direct relaxation mechanism is incorporated through a time decaying exponential

  14. Measuring the role of seagrasses in regulating sediment surface elevation

    KAUST Repository

    Potouroglou, Maria; Bull, James C.; Krauss, Ken W.; Kennedy, Hilary A.; Fusi, Marco; Daffonchio, Daniele; Mangora, Mwita M.; Githaiga, Michael N.; Diele, Karen; Huxham, Mark

    2017-01-01

    in varying hydrogeomorphological conditions over long periods. In contrast, similar evidence for seagrasses is sparse; the present study is a contribution towards filling this gap. Surface elevation change pins were deployed in four locations, Scotland, Kenya

  15. Surface pressure retrieval from SCIAMACHY measurements in the O2 A Band: validation of the measurements and sensitivity on aerosols

    Directory of Open Access Journals (Sweden)

    B. van Diedenhoven

    2005-01-01

    Full Text Available We perform surface pressure retrievals from cloud-free Oxygen A band measurements of SCIAMACHY. These retrievals can be well validated because surface pressure is a quantity that is, in general, accurately known from meteorological models. Therefore, surface pressure retrievals and their validation provide important insight into the quality of the instrument calibration. Furthermore, they can provide insight into retrievals which are affected by similar radiation transport processes, for example the retrieval of total columns of H2O, CO, CO2 and CH4. In our retrieval aerosols are neglected. Using synthetic measurements, it is shown that for low to moderate surface albedos this leads to an underestimation of the retrieved surface pressures. For high surface albedos this generally leads to an overestimation of the retrieved surface pressures. The surface pressures retrieved from the SCIAMACHY measurements indeed show this dependence on surface albedo, when compared to the corresponding pressures from a meteorological database. However, an offset of about 20 hPa was found, which can not be caused by neglecting aerosols in the retrieval. The same offset was found when comparing the retrieved surface pressures to those retrieved from co-located GOME Oxygen A band measurements. This implies a calibration error in the SCIAMACHY measurements. By adding an offset of 0.86% of the continuum reflectance at 756 nm to the SCIAMACHY reflectance measurements, this systematic bias vanishes.

  16. Measuring the surface inhomogeneity of metals on accreting white dwarfs

    International Nuclear Information System (INIS)

    Montgomery, M H; Hippel, T von; Thompson, S E

    2009-01-01

    Due to the short settling times of metals in DA white dwarf atmospheres, any white dwarfs with photospheric metals must be actively accreting. It is therefore natural to expect that the metals may not be deposited uniformly on the surface of the star. We present calculations showing how the temperature variations associated with white dwarf pulsations lead to an observable diagnostic of the surface metal distribution, and we show what constraints current data sets are able to provide.

  17. Image potential effect on the specular reflection coefficient of alkali ions scattered from a nickel surface at low energy

    International Nuclear Information System (INIS)

    Zemih, R.; Boudjema, M.; Benazeth, C.; Boudouma, Y.; Chami, A.C.

    2002-01-01

    The resonant charge exchange in the incoming path of alkali ions scattered at low energy from a polycrystalline nickel surface is studied by using the image effect occurring at glancing incidence (2-10 deg. from the surface plane) and for specular reflection. The part of the experimental artefacts (geometrical factor, surface roughness ...) is extracted from the reflection coefficient of almost completely neutralised projectiles (He + or Ne + ) compared with the coefficient obtained from numerical simulations (TRIM and MARLOWE codes). The present model explains very well the lowering of the reflection coefficient measured at grazing incidence (below 4 deg.). Furthermore, the optimised values of the charge fraction in the incoming path and the image potential are in agreement with the theoretical calculations in the case of Na + /Ni at 4 keV

  18. Structural dependence of the 5d-metal surface energies as deduced from surface core-level shift measurements

    International Nuclear Information System (INIS)

    Mrartensson, N.; Saalfeld, H.B.; Kuhlenbeck, H.; Neumann, M.

    1989-01-01

    Surface core-level shift measurements performed at the BESSY storage ring yield -0.41(2) eV for Os(0001) and 0.00(10) eV for Re(0001). An analysis of the surface shifts in the 5d transition series shows that the surface energy as a function of Z has a maximum at lower Z for the bcc phase than for the fcc-hcp phases, at W and between Re and Os, respectively

  19. Depletion region surface effects in electron beam induced current measurements

    Energy Technology Data Exchange (ETDEWEB)

    Haney, Paul M.; Zhitenev, Nikolai B. [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Yoon, Heayoung P. [Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112 (United States); Gaury, Benoit [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Maryland NanoCenter, University of Maryland, College Park, Maryland 20742 (United States)

    2016-09-07

    Electron beam induced current (EBIC) is a powerful characterization technique which offers the high spatial resolution needed to study polycrystalline solar cells. Current models of EBIC assume that excitations in the p-n junction depletion region result in perfect charge collection efficiency. However, we find that in CdTe and Si samples prepared by focused ion beam (FIB) milling, there is a reduced and nonuniform EBIC lineshape for excitations in the depletion region. Motivated by this, we present a model of the EBIC response for excitations in the depletion region which includes the effects of surface recombination from both charge-neutral and charged surfaces. For neutral surfaces, we present a simple analytical formula which describes the numerical data well, while the charged surface response depends qualitatively on the location of the surface Fermi level relative to the bulk Fermi level. We find that the experimental data on FIB-prepared Si solar cells are most consistent with a charged surface and discuss the implications for EBIC experiments on polycrystalline materials.

  20. Self-assembled monolayers of semi-fluorinated thiols and disulfides with a potentially antibacterial terminal fragment on gold surfaces

    International Nuclear Information System (INIS)

    Thebault, P.; Taffin de Givenchy, E.; Guittard, F.; Guimon, C.; Geribaldi, S.

    2008-01-01

    Attempts to elaborate the best organized cationic self-assembled monolayers (SAMs) with sulfur derivatives containing potentially bactericidal quaternary ammonium salt moieties have been performed on gold with the final aim to obtain contact-active antibacterial surfaces. Four molecules bearing two hydrocarbon spacers with different lengths between the sulfur atom and the quaternized nitrogen atom, and two different terminal semi-fluorinated alkyl chains have been synthesised and used in view to evaluate their capacity for leading to the highest densities and the highest organization of potentially active molecules on the metal surface. The formation and quality of SAMs characterized by X-ray photoelectron spectroscopy, Internal Reflexion Infra Red Imaging, contact angle and blocking factor measurements depend on the lengths of both the hydrocarbon spacer and terminal perfluorinated chain

  1. Potential of non-invasive esophagus cancer detection based on urine surface-enhanced Raman spectroscopy

    Science.gov (United States)

    Huang, Shaohua; Wang, Lan; Chen, Weisheng; Feng, Shangyuan; Lin, Juqiang; Huang, Zufang; Chen, Guannan; Li, Buhong; Chen, Rong

    2014-11-01

    Non-invasive esophagus cancer detection based on urine surface-enhanced Raman spectroscopy (SERS) analysis was presented. Urine SERS spectra were measured on esophagus cancer patients (n = 56) and healthy volunteers (n = 36) for control analysis. Tentative assignments of the urine SERS spectra indicated some interesting esophagus cancer-specific biomolecular changes, including a decrease in the relative content of urea and an increase in the percentage of uric acid in the urine of esophagus cancer patients compared to that of healthy subjects. Principal component analysis (PCA) combined with linear discriminant analysis (LDA) was employed to analyze and differentiate the SERS spectra between normal and esophagus cancer urine. The diagnostic algorithms utilizing a multivariate analysis method achieved a diagnostic sensitivity of 89.3% and specificity of 83.3% for separating esophagus cancer samples from normal urine samples. These results from the explorative work suggested that silver nano particle-based urine SERS analysis coupled with PCA-LDA multivariate analysis has potential for non-invasive detection of esophagus cancer.

  2. Potential of non-invasive esophagus cancer detection based on urine surface-enhanced Raman spectroscopy

    International Nuclear Information System (INIS)

    Huang, Shaohua; Wang, Lan; Feng, Shangyuan; Lin, Juqiang; Huang, Zufang; Chen, Guannan; Li, Buhong; Chen, Rong; Chen, Weisheng

    2014-01-01

    Non-invasive esophagus cancer detection based on urine surface-enhanced Raman spectroscopy (SERS) analysis was presented. Urine SERS spectra were measured on esophagus cancer patients (n = 56) and healthy volunteers (n = 36) for control analysis. Tentative assignments of the urine SERS spectra indicated some interesting esophagus cancer-specific biomolecular changes, including a decrease in the relative content of urea and an increase in the percentage of uric acid in the urine of esophagus cancer patients compared to that of healthy subjects. Principal component analysis (PCA) combined with linear discriminant analysis (LDA) was employed to analyze and differentiate the SERS spectra between normal and esophagus cancer urine. The diagnostic algorithms utilizing a multivariate analysis method achieved a diagnostic sensitivity of 89.3% and specificity of 83.3% for separating esophagus cancer samples from normal urine samples. These results from the explorative work suggested that silver nano particle-based urine SERS analysis coupled with PCA–LDA multivariate analysis has potential for non-invasive detection of esophagus cancer. (letter)

  3. Design and surface modification of potential luminomagnetic nanocarriers for biomedical applications

    International Nuclear Information System (INIS)

    Dutta, Ranu K.; Sharma, Prashant K.; Pandey, Avinash C.

    2010-01-01

    Targeted delivery of therapeutics possesses the potential to localize therapeutic agents to a specific tissue as a mechanism to enhance treatment efficacy and mitigate side effects. Moeities that combine imaging and therapeutic modalities in a single macromolecular construct may confer advantages in the development and applications of nanomedicine. Here is an insight into the synthesis of luminomagnetic (luminescent and magnetic, simultaneously) nanocarriers of ZnO:Fe, synthesized by a simple co-precipitation method and surface modified by the ligand folate. This functionalized luminomagnetic nanocarrier system is a bioconjugation approach which combines the specificity of folate receptors on cancer cells with the excellent optical and magnetic properties of the nanoparticles so as to develop biocompatible molecular imaging agents, drug delivery systems, and hyperthermia agents. The vibrating sample magnetometer (VSM) studies showed clear hysteresis loops having coercivity 5.1 mT with corresponding magnetization of remanence 7.6 x 10 -3 emu/g, indicating strong magnetic character of the samples. X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements show that these nanoparticles are spherical with 6-9 nm size and hence are quite appropriate for in vivo applications as well. The immobilization of folic acid was confirmed by fourier transform infrared (FTIR) analysis. All these properties make these luminomagnetic nanocarriers one of the most feasible candidates for folate receptor-mediated biomedical applications.

  4. A probability measure for random surfaces of arbitrary genus and bosonic strings in 4 dimensions

    International Nuclear Information System (INIS)

    Albeverio, S.; Hoeegh-Krohn, R.; Paycha, S.; Scarlatti, S.

    1989-01-01

    We define a probability measure describing random surfaces in R D , 3≤D≤13, parametrized by compact Riemann surfaces of arbitrary genus. The measure involves the path space measure for scalar fields with exponential interaction in 2 space time dimensions. We show that it gives a mathematical realization of Polyakov's heuristic measure for bosonic strings. (orig.)

  5. Study of surface potential contamination in radioisotope and radiopharmaceutical production facilities and alternative solutions

    International Nuclear Information System (INIS)

    Suhaedi Muhammad; Rimin Sumantri; Farida Tusafariah; Djarwanti Rahayu Pipin Soedjarwo

    2013-01-01

    Radioisotope and radiopharmaceutical production facilities that exist in their operations around the world in the form of radiological impacts of radiation exposure, contamination of surface and air contamination. Given the number of existing open source in radioisotope and radiopharmaceutical production facility, then the possibility of surface contamination in the work area is quite high. For that to protect the safety and health of both workers, the public and the environment, then the licensee must conduct an inventory of some of the potential that could result in contamination of surfaces in radioisotope and radiopharmaceutical production facilities. Several potential to cause surface contamination in radioisotope and radiopharmaceutical production facilities consist of loss of resources, the VAC system disorders, impaired production facilities, limited resources and lack of work discipline and radioactive waste handling activities. From the study of some potential, there are several alternative solutions that can be implemented by the licensee to address the contamination of the surface so as not to cause adverse radiological impacts for both radiation workers, the public or the environment. (author)

  6. Apparatus and procedure to characterize the surface quality of conductors by measuring the rate of cathode emission as a function of surface electric field strength

    Science.gov (United States)

    Mestayer, Mac; Christo, Steve; Taylor, Mark

    2014-10-21

    A device and method for characterizing quality of a conducting surface. The device including a gaseous ionizing chamber having centrally located inside the chamber a conducting sample to be tested to which a negative potential is applied, a plurality of anode or "sense" wires spaced regularly about the central test wire, a plurality of "field wires" at a negative potential are spaced regularly around the sense, and a plurality of "guard wires" at a positive potential are spaced regularly around the field wires in the chamber. The method utilizing the device to measure emission currents from the conductor.

  7. Quantitative method of measuring cancer cell urokinase and metastatic potential

    Science.gov (United States)

    Morrison, Dennis R. (Inventor)

    1993-01-01

    The metastatic potential of tumors can be evaluated by the quantitative detection of urokinase and DNA. The cell sample selected for examination is analyzed for the presence of high levels of urokinase and abnormal DNA using analytical flow cytometry and digital image analysis. Other factors such as membrane associated urokinase, increased DNA synthesis rates and certain receptors can be used in the method for detection of potentially invasive tumors.

  8. Spatially telescoping measurements for improved characterization of groundwater-surface water interactions

    Science.gov (United States)

    Kikuchi, Colin; Ferre, Ty P.A.; Welker, Jeffery M.

    2012-01-01

    The suite of measurement methods available to characterize fluxes between groundwater and surface water is rapidly growing. However, there are few studies that examine approaches to design of field investigations that include multiple methods. We propose that performing field measurements in a spatially telescoping sequence improves measurement flexibility and accounts for nested heterogeneities while still allowing for parsimonious experimental design. We applied this spatially telescoping approach in a study of ground water-surface water (GW-SW) interaction during baseflow conditions along Lucile Creek, located near Wasilla, Alaska. Catchment-scale data, including channel geomorphic indices and hydrogeologic transects, were used to screen areas of potentially significant GW-SW exchange. Specifically, these data indicated increasing groundwater contribution from a deeper regional aquifer along the middle to lower reaches of the stream. This initial assessment was tested using reach-scale estimates of groundwater contribution during baseflow conditions, including differential discharge measurements and the use of chemical tracers analyzed in a three-component mixing model. The reach-scale measurements indicated a large increase in discharge along the middle reaches of the stream accompanied by a shift in chemical composition towards a regional groundwater end member. Finally, point measurements of vertical water fluxes -- obtained using seepage meters as well as temperature-based methods -- were used to evaluate spatial and temporal variability of GW-SW exchange within representative reaches. The spatial variability of upward fluxes, estimated using streambed temperature mapping at the sub-reach scale, was observed to vary in relation to both streambed composition and the magnitude of groundwater contribution from differential discharge measurements. The spatially telescoping approach improved the efficiency of this field investigation. Beginning our assessment

  9. On the influence of the intermolecular potential on the wetting properties of water on silica surfaces

    Science.gov (United States)

    Pafong, E.; Geske, J.; Drossel, B.

    2016-09-01

    We study the wetting properties of water on silica surfaces using molecular dynamics (MD) simulations. To describe the intermolecular interaction between water and silica atoms, two types of interaction potential models are used: the standard BródkA and Zerda (BZ) model and the Gulmen and Thompson (GT) model. We perform an in-depth analysis of the influence of the choice of the potential on the arrangement of the water molecules in partially filled pores and on top of silica slabs. We find that at moderate pore filling ratios, the GT silica surface is completely wetted by water molecules, which agrees well with experimental findings, while the commonly used BZ surface is less hydrophilic and is only partially wetted. We interpret our simulation results using an analytical calculation of the phase diagram of water in partially filled pores. Moreover, an evaluation of the contact angle of the water droplet on top of the silica slab reveals that the interaction becomes more hydrophilic with increasing slab thickness and saturates around 2.5-3 nm, in agreement with the experimentally found value. Our analysis also shows that the hydroaffinity of the surface is mainly determined by the electrostatic interaction, but the van der Waals interaction nevertheless is strong enough that it can turn a hydrophobic surface into a hydrophilic surface.

  10. Recent characterization activities of Midway Valley as a potential repository surface facility site

    International Nuclear Information System (INIS)

    Gibson, J.D.; Wesling, J.R.; Swan, F.H.; Bullard, T.F.

    1992-01-01

    Midway Valley, located at the eastern base of Yucca Mountain, Nye County, Nevada, has been identified as a possible location for the surface facilities of a potential high-level nuclear-waste repository. This structural and topographic valley is bounded by two north- trending, down-to-the-west normal faults: the Paintbrush Canyon fault on the east and the Bow Ridge fault on the west. Surface and near-surface geological data have been acquired from Midway Valley during the past three years with particular emphasis on evaluating the existence of Quaternary faults. A detailed (1:6000) surficial geological map has been prepared based on interpretation of new and existing aerial photographs, field mapping, soil pits, and trenches. No evidence was found that would indicate displacement of these surficial deposits along previously unrecognized faults. However, given the low rates of Quaternary faulting and the extensive areas that are covered by late Pleistocene to Holocene deposits south of Sever Wash, Quaternary faulting between known faults cannot be precluded based on surface evidence alone. Middle to late Pleistocene alluvial fan deposits (Unit Q3) exist at or near the surface throughout Midway Valley. Confidence is increased that the potential for surface fault rupture in Midway Valley can be assessed by excavations that expose the deposits and soils associated with Unit Q3 or older units (middle Pleistocene or earlier)

  11. Lunar Surface Electric Potential Changes Associated with Traversals through the Earth's Foreshock

    Science.gov (United States)

    Collier, Michael R.; Hills, H. Kent; Stubbs, Timothy J.; Halekas, Jasper S.; Delory, Gregory T.; Espley, Jared; Farrell, William M.; Freeman, John W.; Vondrak, Richard

    2011-01-01

    We report an analysis of one year of Suprathermal Ion Detector Experiment (SIDE) Total Ion Detector (TID) resonance events observed between January 1972 and January 1973. The study includes only those events during which upstream solar wind conditions were readily available. The analysis shows that these events are associated with lunar traversals through the dawn flank of the terrestrial magnetospheric bow shock. We propose that the events result from an increase in lunar surface electric potential effected by secondary electron emission due to primary electrons in the Earth's foreshock region (although primary ions may play a role as well). This work establishes (1) the lunar surface potential changes as the Moon moves through the terrestrial bow shock, (2) the lunar surface achieves potentials in the upstream foreshock region that differ from those in the downstream magnetosheath region, (3) these differences can be explained by the presence of energetic electron beams in the upstream foreshock region and (4) if this explanation is correct, the location of the Moon with respect to the terrestrial bow shock influences lunar surface potential.

  12. Dipyridamole Body Surface Potential Mapping: Noninvasive Differentiation of Syndrome X from Coronary Artery Disease

    Czech Academy of Sciences Publication Activity Database

    Boudík, F.; Anger, Z.; Aschermann, M.; Vojáček, J.; Tomečková, Marie

    2002-01-01

    Roč. 35, č. 3 (2002), s. 181-191 ISSN 0022-0736 R&D Projects: GA MZd IZ4038 Keywords : body surface potential mapping * dipyridamole * coronary artery disease * syndrome X Subject RIV: BD - Theory of Information Impact factor: 0.599, year: 2002

  13. Modified-surface-energy methods for deriving heavy-ion potentials

    International Nuclear Information System (INIS)

    Sierk, A.J.

    1977-01-01

    The use of a modified-surface-energy approach for the calculation of heavy-ion interaction potentials is discussed. It is not possible to simultaneously fit elastic scattering, ion interaction barriers, and fission barriers with the same set of constants in this model. Possible explanations of this deficiency are discussed

  14. A new analytical potential energy surface for the adsorption systemk CO/Cu(100)

    NARCIS (Netherlands)

    Marquardt, R.; Cuvelier, F.; Olsen, R.A.; Baerends, E.J.; Tremblay, J.C.; Saalfrank, P.

    2010-01-01

    Electronic structure data and analytical representations of the potential energy surface for the adsorption of carbon monoxide on a crystalline copper Cu(100) substrate are reviewed. It is found that a previously published and widely used analytical hypersurface for this process [J. C. Tully, M.

  15. Potential of public transit as a transportation control measure: Case studies

    Energy Technology Data Exchange (ETDEWEB)

    Sillings, M.

    1998-07-01

    This report is the final product of the Clean Air Project of the National Association of Regional Councils/NARC. It documents a nationwide study of transit projects and programs initiated in the wake of the 1990 Clean Air Act Amendments/CAAA and the Intermodal Surface Transportation Efficiency Act of 1991/ISTEA. The study purpose was to assess the experience, limitations, and value of public transit as a potential transportation control measure/TCM, i.e., generates significant air quality benefits by eliminating or reducing emissions from motor vehicles. Four in-depth case studies and six additional projects featured as innovations in transportation are offered as examples investigating the potential of transit as a TCM. These case studies and innovations highlight the efforts of ten metropolitan areas and transit agencies which have succeed in developing and implementing innovative transit strategies.

  16. Impact of organic overlayers on a-Si:H/c-Si surface potential

    KAUST Repository

    Seif, Johannes P.

    2017-04-11

    Bilayers of intrinsic and doped hydrogenated amorphous silicon, deposited on crystalline silicon (c-Si) surfaces, simultaneously provide contact passivation and carrier collection in silicon heterojunction solar cells. Recently, we have shown that the presence of overlaying transparent conductive oxides can significantly affect the c-Si surface potential induced by these amorphous silicon stacks. Specifically, deposition on the hole-collecting bilayers can result in an undesired weakening of contact passivation, thereby lowering the achievable fill factor in a finished device. We test here a variety of organic semiconductors of different doping levels, overlaying hydrogenated amorphous silicon layers and silicon-based hole collectors, to mitigate this effect. We find that these materials enhance the c-Si surface potential, leading to increased implied fill factors. This opens opportunities for improved device performance.

  17. Surface potential at a ferroelectric grain due to asymmetric screening of depolarization fields

    Energy Technology Data Exchange (ETDEWEB)

    Genenko, Yuri A., E-mail: genenko@mm.tu-darmstadt.de; Hirsch, Ofer [Technische Universität Darmstadt, Darmstadt (Germany); Erhart, Paul [Chalmers University of Technology, Gothenburg (Sweden)

    2014-03-14

    Nonlinear screening of electric depolarization fields, generated by a stripe domain structure in a ferroelectric grain of a polycrystalline material, is studied within a semiconductor model of ferroelectrics. It is shown that the maximum strength of local depolarization fields is rather determined by the electronic band gap than by the spontaneous polarization magnitude. Furthermore, field screening due to electronic band bending and due to presence of intrinsic defects leads to asymmetric space charge regions near the grain boundary, which produce an effective dipole layer at the surface of the grain. This results in the formation of a potential difference between the grain surface and its interior of the order of 1 V, which can be of either sign depending on defect transition levels and concentrations. Exemplary acceptor doping of BaTiO{sub 3} is shown to allow tuning of the said surface potential in the region between 0.1 and 1.3 V.

  18. Construction of an interatomic potential for zinc oxide surfaces by high-dimensional neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Artrith, Nongnuch; Morawietz, Tobias; Behler, Joerg [Lehrstuhl fuer Theoretische Chemie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

    2011-07-01

    Zinc oxide (ZnO) is a technologically important material with many applications, e.g. in heterogeneous catalysis. For theoretical studies of the structural properties of ZnO surfaces, defects, and crystal structures it is necessary to simulate large systems over long time-scales with sufficient accuracy. Often, the required system size is not accessible by computationally rather demanding density-functional theory (DFT) calculations. Recently, artificial Neural Networks (NN) trained to first principles data have shown to provide accurate potential-energy surfaces (PESs) for condensed systems. We present the construction and analysis of a NN PES for ZnO. The structural and energetic properties of bulk ZnO and ZnO surfaces are investigated using this potential and compared to DFT calculations.

  19. Impact of organic overlayers on a-Si:H/c-Si surface potential

    KAUST Repository

    Seif, Johannes P.; Niesen, Bjoern; Tomasi, Andrea; Ballif, Christophe; De Wolf, Stefaan

    2017-01-01

    Bilayers of intrinsic and doped hydrogenated amorphous silicon, deposited on crystalline silicon (c-Si) surfaces, simultaneously provide contact passivation and carrier collection in silicon heterojunction solar cells. Recently, we have shown that the presence of overlaying transparent conductive oxides can significantly affect the c-Si surface potential induced by these amorphous silicon stacks. Specifically, deposition on the hole-collecting bilayers can result in an undesired weakening of contact passivation, thereby lowering the achievable fill factor in a finished device. We test here a variety of organic semiconductors of different doping levels, overlaying hydrogenated amorphous silicon layers and silicon-based hole collectors, to mitigate this effect. We find that these materials enhance the c-Si surface potential, leading to increased implied fill factors. This opens opportunities for improved device performance.

  20. Potential dependence of surface crystal structure of iron passive films in borate buffer solution

    International Nuclear Information System (INIS)

    Deng, Huihua; Nanjo, Hiroshi; Qian, Pu; Santosa, Arifin; Ishikawa, Ikuo; Kurata, Yoshiaki

    2007-01-01

    The effect of passivation potential on surface crystal structure, apparent thickness and passivity of oxide films formed on pure iron prepared by plasma sputter deposition was investigated. The crystallinity was improved with passivation potential and the width of atomically flat terraces was expanded to 6 nm when passivating at 750 mV for 15 min, as observed by ex situ scanning tunneling microscopy (STM) after aging in air (<30% RH). Apparent thickness and passivity are linearly dependent on passivation potential. The former weakly depends on passivation duration, the latter strongly depends on passivation duration. This is well explained by the correlation between crystal structure and passivity

  1. Refined potentials for rare gas atom adsorption on rare gas and alkali-halide surfaces

    Science.gov (United States)

    Wilson, J. W.; Heinbockel, J. H.; Outlaw, R. A.

    1985-01-01

    The utilization of models of interatomic potential for physical interaction to estimate the long range attractive potential for rare gases and ions is discussed. The long range attractive force is calculated in terms of the atomic dispersion properties. A data base of atomic dispersion parameters for rare gas atoms, alkali ion, and halogen ions is applied to the study of the repulsive core; the procedure for evaluating the repulsive core of ion interactions is described. The interaction of rare gas atoms on ideal rare gas solid and alkali-halide surfaces is analyzed; zero coverage absorption potentials are derived.

  2. Monitoring of Cyclic Steam Stimulation by Inversion of Surface Tilt Measurements

    Science.gov (United States)

    Maharramov, M.; Zoback, M. D.

    2014-12-01

    Temperature and pressure changes associated with the cyclic steam simulation (CSS) used in heavy oil production from sands are accompanied by significant deformation. Inversion of geomechanical data may provide a potentially powerful reservoir monitoring tool where geomechanical effects are significant. Induced pore pressure changes can be inverted from measurable surface deformations by solving an inverse problem of poroelasticity. In this work, we apply this approach to estimating pore pressure changes from surface tilt measurements at a heavy oil reservoir undergoing cyclic steam simulation. Steam was injected from November 2007 through January 2008. Surface tilt measurements were collected from 25 surface tilt stations during this period. The injection ran in two overlapping phases: Phase 1 ran from the beginning of the injection though mid-December, and Phase 2 overlapped with Phase 1 and ran through the beginning of January. During Phase 1 steam was injected in the western part of the reservoir, followed by injection in the eastern part in Phase 2. The pore pressure evolution was inverted from daily tilt measurements using regularized constrained least squares fitting, the results are shown on the plot. Estimated induced pore pressure change (color scale), observed daily incremental tilts (green arrows) and modeled daily incremental tilts (red arrows) are shown in three panels corresponding to two and five weeks of injection, and the end of injection period. DGPS measurements available for a single location were used as an additional inversion constraint. The results indicate that the pore pressure increase in the reservoir follows the same pattern as the steam injection, from west to east. This qualitative behaviour is independent of the amount of regularization, indirectly validating our inversion approach. Patches of lower pressure appear to be stable with regard to regularization and may provide valuable insight into the efficiency of steam injection

  3. Measuring the role of seagrasses in regulating sediment surface elevation

    KAUST Repository

    Potouroglou, Maria

    2017-09-13

    Seagrass meadows provide numerous ecosystem services and their rapid global loss may reduce human welfare as well as ecological integrity. In common with the other \\'blue carbon\\' habitats (mangroves and tidal marshes) seagrasses are thought to provide coastal defence and encourage sediment stabilisation and surface elevation. A sophisticated understanding of sediment elevation dynamics in mangroves and tidal marshes has been gained by monitoring a wide range of different sites, located in varying hydrogeomorphological conditions over long periods. In contrast, similar evidence for seagrasses is sparse; the present study is a contribution towards filling this gap. Surface elevation change pins were deployed in four locations, Scotland, Kenya, Tanzania and Saudi Arabia, in both seagrass and unvegetated control plots in the low intertidal and shallow subtidal zone. The presence of seagrass had a highly significant, positive impact on surface elevation at all sites. Combined data from the current work and the literature show an average difference of 31 mm per year in elevation rates between vegetated and unvegetated areas, which emphasizes the important contribution of seagrass in facilitating sediment surface elevation and reducing erosion. This paper presents the first multi-site study for sediment surface elevation in seagrasses in different settings and species.

  4. Measuring the role of seagrasses in regulating sediment surface elevation

    Science.gov (United States)

    Potouroglou, Maria; Bull, James C.; Krauss, Ken W.; Kennedy, Hilary A.; Fusi, Marco; Daffonchio, Daniele; Mangora, Mwita M.; Githaiga, Michael N.; Diele, Karen; Huxham, Mark

    2017-01-01

    Seagrass meadows provide numerous ecosystem services and their rapid global loss may reduce human welfare as well as ecological integrity. In common with the other ‘blue carbon’ habitats (mangroves and tidal marshes) seagrasses are thought to provide coastal defence and encourage sediment stabilisation and surface elevation. A sophisticated understanding of sediment elevation dynamics in mangroves and tidal marshes has been gained by monitoring a wide range of different sites, located in varying hydrogeomorphological conditions over long periods. In contrast, similar evidence for seagrasses is sparse; the present study is a contribution towards filling this gap. Surface elevation change pins were deployed in four locations, Scotland, Kenya, Tanzania and Saudi Arabia, in both seagrass and unvegetated control plots in the low intertidal and shallow subtidal zone. The presence of seagrass had a highly significant, positive impact on surface elevation at all sites. Combined data from the current work and the literature show an average difference of 31 mm per year in elevation rates between vegetated and unvegetated areas, which emphasizes the important contribution of seagrass in facilitating sediment surface elevation and reducing erosion. This paper presents the first multi-site study for sediment surface elevation in seagrasses in different settings and species.

  5. Measurement campaign for wind power potential in west Greenland

    Science.gov (United States)

    Rønnow Jakobsen, Kasper

    2013-04-01

    Experiences and results from a wind resource exploring campaign 2003- in west Greenland. Like many other countries, Greenland is trying to reduce its dependency of fossil fuel by implementing renewable energy. The main challenge is that the people live on the coast in scattered settlements, without power infrastructure. Based on this a wind power potential project was established in 2002, funded by the Greenlandic government and the Technical University of Denmark. We present results and experiences of the campaign. 1 Field campaign There were only a few climate stations in or close to settlements and due to their positioning and instrumentation, they were not usable for wind resource estimation. To establish met stations in Arctic areas with complex topography, there are some challenges to face; mast positioning in complex terrain, severe weather conditions, instrumentation, data handling, installation and maintenance budget. The terrain in the ice free and populated part, mainly consists of mountains of different heights and shapes, separated by deep fjords going from the ice cap to the sea. With a generally low wind resource the focus was on the most exposed positions close to the settlements. Data from the nearest existing climate stations was studied for background estimations of predominant wind directions and extreme wind speeds, and based on that the first 10m masts were erected in 2003. 2 Instruments The first installations used standard NRG systems with low cost NRG instruments. For most of the sites this low cost setup did a good job, but there were some problems with the first design, including instrument and boom strains. In subsequent years, the systems were updated several times to be able to operate in the extreme conditions. Different types of instruments, data logger and boom systems were tested to get better data quality and reliability. Today 11 stations with heights ranging from 10-50m are installed and equipped according to the IEC standard

  6. Image-potential states on the metallic (111) surface of bismuth

    International Nuclear Information System (INIS)

    Muntwiler, Matthias; Zhu, X-Y

    2008-01-01

    An extended series (up to n=6, in quantum beats) of image-potential states (IPS) is observed in time-resolved two-photon photoelectron (TR-2PPE) spectroscopy of the Bi(111) surface. Although mainly located in the vacuum, these states probe various properties of the electronic structure of the surface as reflected in their energetics and dynamics. Based on the observation of IPS a projected gap in the surface normal direction is inferred in the region from 3.57 to 4.27 eV above the Fermi level. Despite this band gap, the lifetimes of the IPS are shorter than on comparable metals, which is an indication of the metallic character of the Bi(111) surface.

  7. Antarctic Ice Shelf Potentially Stabilized by Export of Meltwater in Surface River

    Science.gov (United States)

    Bell, Robin E.; Chu, Winnie; Kingslake, Jonathan; Das, Indrani; Tedesco, Marco; Tinto, Kirsty J.; Zappa, Christopher J.; Frezzotti, Massimo; Boghosian, Alexandra; Lee, Won Sang

    2017-01-01

    Meltwater stored in ponds and crevasses can weaken and fracture ice shelves, triggering their rapid disintegration. This ice-shelf collapse results in an increased flux of ice from adjacent glaciers and ice streams, thereby raising sea level globally. However, surface rivers forming on ice shelves could potentially export stored meltwater and prevent its destructive effects. Here we present evidence for persistent active drainage networks-interconnected streams, ponds and rivers-on the Nansen Ice Shelf in Antarctica that export a large fraction of the ice shelf's meltwater into the ocean. We find that active drainage has exported water off the ice surface through waterfalls and dolines for more than a century. The surface river terminates in a 130-metre-wide waterfall that can export the entire annual surface melt over the course of seven days. During warmer melt seasons, these drainage networks adapt to changing environmental conditions by remaining active for longer and exporting more water. Similar networks are present on the ice shelf in front of Petermann Glacier, Greenland, but other systems, such as on the Larsen C and Amery Ice Shelves, retain surface water at present. The underlying reasons for export versus retention remain unclear. Nonetheless our results suggest that, in a future warming climate, surface rivers could export melt off the large ice shelves surrounding Antarctica-contrary to present Antarctic ice-sheet models, which assume that meltwater is stored on the ice surface where it triggers ice-shelf disintegration.

  8. Development of an Urban Multilayer Radiation Scheme and Its Application to the Urban Surface Warming Potential

    Science.gov (United States)

    Aoyagi, Toshinori; Takahashi, Shunji

    2012-02-01

    To investigate how a three-dimensional structure such as an urban canyon can affect urban surface warming, we developed an urban multilayer radiation scheme. The complete consideration of multiple scattering of shortwave and longwave radiation using the radiosity method is an important feature of the present scheme. A brief description of this scheme is presented, followed by evaluations that compare its results with observations of the effective albedo and radiative temperature for urban blocks. Next, we calculate the urban surface warming potential (USWP), defined as the difference between the daily mean radiative temperature of urban surfaces (which are assumed to be black bodies), including their canyon effects and the daily mean temperature of a flat surface with the same material properties, under a radiative equilibrium state. Assuming standard material properties (albedo and emissivity of 0.4 and 0.9, respectively), we studied the sensitivity of the USWP to various aspect ratios of building heights to road widths. The results show that the temporally-averaged surface temperature of an urban area can be higher than that of a flat surface. In addition, we determined the overestimation of the effective temperature of urban surfaces induced by the overestimation of the radiation distribution to the walls when one uses a single-layer scheme for urban block arrays that have a low sky-view factor less than around 0.5.

  9. Monolayer alignment on azobenzene surfaces during UV light irradiation: Analysis of optical polarized absorption measurement results and theoretical treatment

    International Nuclear Information System (INIS)

    Zakharov, A.V.; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa

    2006-01-01

    The influence of the charge separation during the trans-cis conformational change on the surface of azobenzene 6Az10PVA monolayer on the polar liquid-crystal monolayer film, such as 4-n-pentyl-4 ' -cyanobiphenyl(5CB), is investigated. The effective anchoring energy (in the Rapini-Papolar form) is phenomenologically described in the framework of the molecular model, which takes into account the interaction between the surface polarization and surface electric field, for number of conformational states of the boundary surface. It is shown, using the experimental data for the voltage across the 6Az10PVA+5CB film, provided by the surface-potential technique, that the charge separation during the conformational changing, caused by the UV irradiation, may lead to changing of the surface alignment of liquid-crystalline molecules. The influence of the photoisomerization process on the orientational order parameter S 2 (t) using the optical polarized absorption measurement is also investigated

  10. Numerical simulations of electric potential field for alternating current potential drop associated with surface cracks in low-alloy steel nuclear material

    Science.gov (United States)

    Yeh, Chun-Ping; Huang, Jiunn-Yuan

    2018-04-01

    Low-alloy steels used as structural materials in nuclear power plants are subjected to cyclic stresses during power plant operations. As a result, cracks may develop and propagate through the material. The alternating current potential drop technique is used to measure the lengths of cracks in metallic components. The depth of the penetration of the alternating current is assumed to be small compared to the crack length. This assumption allows the adoption of the unfolding technique to simplify the problem to a surface Laplacian field. The numerical modelling of the electric potential and current density distribution prediction model for a compact tension specimen and the unfolded crack model are presented in this paper. The goal of this work is to conduct numerical simulations to reduce deviations occurring in the crack length measurements. Numerical simulations were conducted on AISI 4340 low-alloy steel with different crack lengths to evaluate the electric potential distribution. From the simulated results, an optimised position for voltage measurements in the crack region was proposed.

  11. Estimation of daily global solar radiation as a function of the solar energy potential at soil surface

    International Nuclear Information System (INIS)

    Pereira, A.B.; Vrisman, A.L.; Galvani, E.

    2002-01-01

    The solar radiation received at the surface of the earth, apart from its relevance to several daily human activities, plays an important role in the growth and development of plants. The aim of the current work was to develop and gauge an estimation model for the evaluation of the global solar radiation flux density as a function of the solar energy potential at soil surface. Radiometric data were collected at Ponta Grossa, PR, Brazil (latitude 25°13' S, longitude 50°03' W, altitude 880 m). Estimated values of solar energy potential obtained as a function of only one measurement taken at solar noon time were confronted with those measured by a Robitzsch bimetalic actinograph, for days that presented insolation ratios higher than 0.85. This data set was submitted to a simple linear regression analysis, having been obtained a good adjustment between observed and calculated values. For the estimation of the coefficients a and b of Angström's equation, the method based on the solar energy potential at soil surface was used for the site under study. The methodology was efficient to assess the coefficients, aiming at the determination of the global solar radiation flux density, whith quickness and simplicity, having also found out that the criterium for the estimation of the solar energy potential is equivalent to that of the classical methodology of Angström. Knowledge of the available solar energy potential and global solar radiation flux density is of great importance for the estimation of the maximum atmospheric evaporative demand, of water consumption by irrigated crops, and also for building solar engineering equipment, such as driers, heaters, solar ovens, refrigerators, etc [pt

  12. Oxidation of clean silicon surfaces studied by four-point probe surface conductance measurements

    DEFF Research Database (Denmark)

    Petersen, Christian Leth; Grey, Francois; Aono, M.

    1997-01-01

    We have investigated how the conductance of Si(100)-(2 x 1) and Si(111)-(7 x 7) surfaces change during exposure to molecular oxygen. A monotonic decrease in conductance is seen as the (100) surfaces oxidizes. In contract to a prior study, we propose that this change is caused by a decrease in sur...

  13. Mechanical Q-factor measurements on a test mass with a structured surface

    Energy Technology Data Exchange (ETDEWEB)

    Nawrodt, R [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany); Zimmer, A [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany); Koettig, T [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany); Clausnitzer, T [Institut fuer Angewandte Physik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany); Bunkowski, A [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Institut fuer Gravitationsphysik, Leibniz Universitaet Hannover, Callinstr. 38, D-30167 Hannover (Germany); Kley, E B [Institut fuer Angewandte Physik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany); Schnabel, R [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Institut fuer Gravitationsphysik, Leibniz Universitaet Hannover, Callinstr. 38, D-30167 Hannover (Germany); Danzmann, K [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Institut fuer Gravitationsphysik, Leibniz Universitaet Hannover, Callinstr. 38, D-30167 Hannover (Germany); Nietzsche, S [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany); Vodel, W [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany); Tuennermann, A [Institut fuer Angewandte Physik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany); Seidel, P [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Helmholtzweg 5, D-07743 Jena (Germany)

    2007-07-15

    We present mechanical Q-factors (quality factors) of a crystalline quartz test mass with a nano-structured surface, measured in the temperature regime from 5 to 300 K. The nano-structure was a grating with a period of 2 {mu}m and a depth of about 0.1 {mu}m. Comparative measurements were performed on the plain substrate and on the structured test mass with different numbers of SiO{sub 2}/Ta{sub 2}O{sub 5} coating layers. The measurements at different stages of the test mass fabrication process show that the surface distortion induced by the nanostructure does not severely lower the mechanical Q-factor of the substrate. Damping due to a multi-layer coating stack was found to be orders of magnitude higher. The results provide vital information concerning the potential usage of low-thermal noise nano-structured test masses in future generations of high-precision laser interferometers and in current attempts to measure quantum effects of macroscopic mirror oscillators.

  14. Hole-to-surface resistivity measurements at Gibson Dome (drill hole GD-1) Paradox basin, Utah

    Science.gov (United States)

    Daniels, J.J.

    1984-01-01

    Hole-to-surface resistivity measurements were made in a deep drill hole (GD-1), in San Juan County, Utah, which penetrated a sequence of sandstone, shale, and evaporite. These measurements were made as part of a larger investigation to study the suitability of an area centered around the Gibson Dome structure for nuclear waste disposal. The magnitude and direction of the total electric field resulting from a current source placed in a drill hole is calculated from potential difference measurements for a grid of closely-spaced stations. A contour map of these data provides a detailed map of the distribution of the electric field away from the drill hole. Computation of the apparent resistivity from the total electric field helps to interpret the data with respect to the ideal situation of a layered earth. Repeating the surface measurements for different source depths gives an indication of variations in the geoelectric section with depth. The quantitative interpretation of the field data at Gibson Dome was hindered by the pressure of a conductive borehole fluid. However, a qualitative interpretation of the field data indicates the geoelectric section around drill hole GD-1 is not perfectly layered. The geoelectric section appears to dip to the northwest, and contains anomalies in the resistivity distribution that may be representative of localized thickening or folding of the salt layers.

  15. Leidenfrost drops cooling surfaces: theory and interferometric measurement

    NARCIS (Netherlands)

    Van Limbeek, Michiel A. J.; Klein Schaarsberg, Martin H.; Sobac, Benjamin; Rednikov, Alexey; Sun, Chao; Colinet, Pierre; Lohse, Detlef

    2017-01-01

    When a liquid drop is placed on a highly superheated surface, it can be levitated by its own vapour. This remarkable phenomenon is referred to as the Leidenfrost effect. The thermally insulating vapour film results in a severe reduction of the heat transfer rate compared to experiments at lower

  16. Automated system for measuring the surface dilational modulus of liquid–air interfaces

    International Nuclear Information System (INIS)

    Stadler, Dominik; Shamonin, Mikhail; Hofmann, Matthias J; Motschmann, Hubert

    2016-01-01

    The surface dilational modulus is a crucial parameter for describing the rheological properties of aqueous surfactant solutions. These properties are important for many technological processes. The present paper describes a fully automated instrument based on the oscillating bubble technique. It works in the frequency range from 1 Hz to 500 Hz, where surfactant exchange dynamics governs the relaxation process. The originality of instrument design is the consistent combination of modern measurement technologies with advanced imaging and signal processing algorithms. Key steps on the way to reliable and precise measurements are the excitation of harmonic oscillation of the bubble, phase sensitive evaluation of the pressure response, adjustment and maintenance of the bubble shape to half sphere geometry for compensation of thermal drifts, contour tracing of the bubbles video images, removal of noise and artefacts within the image for improving the reliability of the measurement, and, in particular, a complex trigger scheme for the measurement of the oscillation amplitude, which may vary with frequency as a result of resonances. The corresponding automation and programming tasks are described in detail. Various programming strategies, such as the use of MATLAB ® software and native C++ code are discussed. An advance in the measurement technique is demonstrated by a fully automated measurement. The instrument has the potential to mature into a standard technique in the fields of colloid and interface chemistry and provides a significant extension of the frequency range to established competing techniques and state-of-the-art devices based on the same measurement principle. (paper)

  17. Influence of crack length on crack depth measurement by an alternating current potential drop technique

    International Nuclear Information System (INIS)

    Raja, Manoj K; Mahadevan, S; Rao, B P C; Behera, S P; Jayakumar, T; Raj, Baldev

    2010-01-01

    An alternating current potential drop (ACPD) technique is used for sizing depth of surface cracks in metallic components. Crack depth estimations are prone to large deviations when ACPD measurements are made on very shallow and finite length cracks, especially in low conducting materials such as austenitic stainless steel (SS). Detailed studies have been carried out to investigate the influence of crack length and aspect ratio (length to depth) on depth estimation by performing measurements on electric discharge machined notches with the aspect ratio in the range of 1 to 40 in SS plates. In notches with finite length, an additional path for current to flow through the surface along the length is available causing the notch depths to be underestimated. The experimentally observed deviation in notch depth estimates is explained from a simple mathematical approach using the equivalent resistive circuit model based on the additional path available for the current to flow. A scheme is proposed to accurately measure the depth of cracks with finite lengths in SS components

  18. Surface and Flow Field Measurements on the FAITH Hill Model

    Science.gov (United States)

    Bell, James H.; Heineck, James T.; Zilliac, Gregory; Mehta, Rabindra D.; Long, Kurtis R.

    2012-01-01

    A series of experimental tests, using both qualitative and quantitative techniques, were conducted to characterize both surface and off-surface flow characteristics of an axisymmetric, modified-cosine-shaped, wall-mounted hill named "FAITH" (Fundamental Aero Investigates The Hill). Two separate models were employed: a 6" high, 18" base diameter machined aluminum model that was used for wind tunnel tests and a smaller scale (2" high, 6" base diameter) sintered nylon version that was used in the water channel facility. Wind tunnel and water channel tests were conducted at mean test section speeds of 165 fps (Reynolds Number based on height = 500,000) and 0.1 fps (Reynolds Number of 1000), respectively. The ratio of model height to boundary later height was approximately 3 for both tests. Qualitative techniques that were employed to characterize the complex flow included surface oil flow visualization for the wind tunnel tests, and dye injection for the water channel tests. Quantitative techniques that were employed to characterize the flow included Cobra Probe to determine point-wise steady and unsteady 3D velocities, Particle Image Velocimetry (PIV) to determine 3D velocities and turbulence statistics along specified planes, Pressure Sensitive Paint (PSP) to determine mean surface pressures, and Fringe Imaging Skin Friction (FISF) to determine surface skin friction (magnitude and direction). This initial report summarizes the experimental set-up, techniques used, data acquired and describes some details of the dataset that is being constructed for use by other researchers, especially the CFD community. Subsequent reports will discuss the data and their interpretation in more detail

  19. Global potential energy surface of ground state singlet spin O4

    Science.gov (United States)

    Mankodi, Tapan K.; Bhandarkar, Upendra V.; Puranik, Bhalchandra P.

    2018-02-01

    A new global potential energy for the singlet spin state O4 system is reported using CASPT2/aug-cc-pVTZ ab initio calculations. The geometries for the six-dimensional surface are constructed using a novel point generation scheme that employs randomly generated configurations based on the beta distribution. The advantage of this scheme is apparent in the reduction of the number of required geometries for a reasonably accurate potential energy surface (PES) and the consequent decrease in the overall computational effort. The reported surface matches well with the recently published singlet surface by Paukku et al. [J. Chem. Phys. 147, 034301 (2017)]. In addition to the O4 PES, the ground state N4 PES is also constructed using the point generation scheme and compared with the existing PES [Y. Paukku et al., J. Chem. Phys. 139, 044309 (2013)]. The singlet surface is constructed with the aim of studying high energy O2-O2 collisions and predicting collision induced dissociation cross section to be used in simulating non-equilibrium aerothermodynamic flows.

  20. Potential energy surface, dipole moment surface and the intensity calculations for the 10 μm, 5 μm and 3 μm bands of ozone

    Science.gov (United States)

    Polyansky, Oleg L.; Zobov, Nikolai F.; Mizus, Irina I.; Kyuberis, Aleksandra A.; Lodi, Lorenzo; Tennyson, Jonathan

    2018-05-01

    Monitoring ozone concentrations in the Earth's atmosphere using spectroscopic methods is a major activity which undertaken both from the ground and from space. However there are long-running issues of consistency between measurements made at infrared (IR) and ultraviolet (UV) wavelengths. In addition, key O3 IR bands at 10 μm, 5 μm and 3 μm also yield results which differ by a few percent when used for retrievals. These problems stem from the underlying laboratory measurements of the line intensities. Here we use quantum chemical techniques, first principles electronic structure and variational nuclear-motion calculations, to address this problem. A new high-accuracy ab initio dipole moment surface (DMS) is computed. Several spectroscopically-determined potential energy surfaces (PESs) are constructed by fitting to empirical energy levels in the region below 7000 cm-1 starting from an ab initio PES. Nuclear motion calculations using these new surfaces allow the unambiguous determination of the intensities of 10 μm band transitions, and the computation of the intensities of 10 μm and 5 μm bands within their experimental error. A decrease in intensities within the 3 μm is predicted which appears consistent with atmospheric retrievals. The PES and DMS form a suitable starting point both for the computation of comprehensive ozone line lists and for future calculations of electronic transition intensities.

  1. Potential fields on the ventricular surface of the exposed dog heart during normal excitation.

    Science.gov (United States)

    Arisi, G; Macchi, E; Baruffi, S; Spaggiari, S; Taccardi, B

    1983-06-01

    We studied the normal spread of excitation on the anterior and posterior ventricular surface of open-chest dogs by recording unipolar electrograms from an array of 1124 electrodes spaced 2 mm apart. The array had the shape of the ventricular surface of the heart. The electrograms were processed by a computer and displayed as epicardial equipotential maps at 1-msec intervals. Isochrone maps also were drawn. Several new features of epicardial potential fields were identified: (1) a high number of breakthrough points; (2) the topography, apparent widths, velocities of the wavefronts and the related potential drop; (3) the topography of positive potential peaks in relation to the wavefronts. Fifteen to 24 breakthrough points were located on the anterior, and 10 to 13 on the posterior ventricular surface. Some were in previously described locations and many others in new locations. Specifically, 3 to 5 breakthrough points appeared close to the atrioventricular groove on the anterior right ventricle and 2 to 4 on the posterior heart aspect; these basal breakthrough points appeared when a large portion of ventricular surface was still unexcited. Due to the presence of numerous breakthrough points on the anterior and posterior aspect of the heart which had not previously been described, the spread of excitation on the ventricular surface was "mosaic-like," with activation wavefronts spreading in all directions, rather than radially from the two breakthrough points, as traditionally described. The positive potential peaks which lay ahead of the expanding wavefronts moved along preferential directions which were probably related to the myocardial fiber direction.

  2. Critical insight into the influence of the potential energy surface on fission dynamics

    International Nuclear Information System (INIS)

    Mazurek, K.; Schmitt, C.; Wieleczko, J. P.; Ademard, G.; Nadtochy, P. N.

    2011-01-01

    The present work is dedicated to a careful investigation of the influence of the potential energy surface on the fission process. The time evolution of nuclei at high excitation energy and angular momentum is studied by means of three-dimensional Langevin calculations performed for two different parametrizations of the macroscopic potential: the Finite Range Liquid Drop Model (FRLDM) and the Lublin-Strasbourg Drop (LSD) prescription. Depending on the mass of the system, the topology of the potential throughout the deformation space of interest in fission is observed to noticeably differ within these two approaches, due to the treatment of curvature effects. When utilized in the dynamical calculation as the driving potential, the FRLDM and LSD models yield similar results in the heavy-mass region, whereas the predictions can be strongly dependent on the Potential Energy Surface (PES) for medium-mass nuclei. In particular, the mass, charge, and total kinetic energy distributions of the fission fragments are found to be narrower with the LSD prescription. The influence of critical model parameters on our findings is carefully investigated. The present study sheds light on the experimental conditions and signatures well suited for constraining the parametrization of the macroscopic potential. Its implication regarding the interpretation of available experimental data is briefly discussed.

  3. Potential energy surfaces for N = Z, 20Ne-112Ba nuclei

    International Nuclear Information System (INIS)

    Mehta, M.S.; Gupta, Raj K.; Jha, T.K.; Patra, S.K.

    2004-01-01

    We have calculated the potential energy surfaces for N = Z, 20 Ne- 112 Ba nuclei in an axially deformed relativistic mean field approach. A quadratic constraint scheme is applied to determine the complete energy surface for a wide range of the quadrupole deformation. The NL3, NL-RAl and TM1 parameter sets are used. The phenomenon of (multiple) shape coexistence is studied and the calculated ground and excited state binding energies, quadrupole deformation parameters and root mean square (rms) charge radii are compared with the available experimental data and other theoretical predictions. (author)

  4. Surface-active biopolymers from marine bacteria for potential biotechnological applications

    Directory of Open Access Journals (Sweden)

    Karina Sałek

    2016-03-01

    Full Text Available Surface-active agents are amphiphilic chemicals that are used in almost every sector of modern industry, the bulk of which are produced by organo-chemical synthesis. Those produced from biological sources (biosurfactants and bioemulsifiers, however, have gained increasing interest in recent years due to their wide structural and functional diversity, lower toxicities and high biodegradability, compared to their chemically-synthesised counterparts. This review aims to present a general overview on surface-active agents, including their classification, where new types of these biomolecules may lay awaiting discovery, and some of the main bottlenecks for their industrial-scale production. In particular, the marine environment is highlighted as a largely untapped source for discovering new types of surface-active agents. Marine bacteria, especially those living associated with micro-algae (eukaryotic phytoplankton, are a highly promising source of polymeric surface-active agents with potential biotechnological applications. The high uronic acids content of these macromolecules has been linked to conferring them with amphiphilic qualities, and their high structural diversity and polyanionic nature endows them with the potential to exhibit a wide range of functional diversity. Production yields (e.g. by fermentation for most microbial surface-active agents have often been too low to meet the volume demands of industry, and this principally remains as the most important bottleneck for their further commercial development. However, new developments in recombinant and synthetic biology approaches can offer significant promise to alleviate this bottleneck. This review highlights a particular biotope in the marine environment that offers promise for discovering novel surface-active biomolecules, and gives a general overview on specific areas that researchers and the industry could focus work towards increasing the production yields of microbial surface

  5. Dynamic Electron Correlation Effects on the Ground State Potential Energy Surface of a Retinal Chromophore Model.

    Science.gov (United States)

    Gozem, Samer; Huntress, Mark; Schapiro, Igor; Lindh, Roland; Granovsky, Alexander A; Angeli, Celestino; Olivucci, Massimo

    2012-11-13

    The ground state potential energy surface of the retinal chromophore of visual pigments (e.g., bovine rhodopsin) features a low-lying conical intersection surrounded by regions with variable charge-transfer and diradical electronic structures. This implies that dynamic electron correlation may have a large effect on the shape of the force fields driving its reactivity. To investigate this effect, we focus on mapping the potential energy for three paths located along the ground state CASSCF potential energy surface of the penta-2,4-dieniminium cation taken as a minimal model of the retinal chromophore. The first path spans the bond length alternation coordinate and intercepts a conical intersection point. The other two are minimum energy paths along two distinct but kinetically competitive thermal isomerization coordinates. We show that the effect of introducing the missing dynamic electron correlation variationally (with MRCISD) and perturbatively (with the CASPT2, NEVPT2, and XMCQDPT2 methods) leads, invariably, to a stabilization of the regions with charge transfer character and to a significant reshaping of the reference CASSCF potential energy surface and suggesting a change in the dominating isomerization mechanism. The possible impact of such a correction on the photoisomerization of the retinal chromophore is discussed.

  6. Accelerating electrostatic surface potential calculation with multi-scale approximation on graphics processing units.

    Science.gov (United States)

    Anandakrishnan, Ramu; Scogland, Tom R W; Fenley, Andrew T; Gordon, John C; Feng, Wu-chun; Onufriev, Alexey V

    2010-06-01

    Tools that compute and visualize biomolecular electrostatic surface potential have been used extensively for studying biomolecular function. However, determining the surface potential for large biomolecules on a typical desktop computer can take days or longer using currently available tools and methods. Two commonly used techniques to speed-up these types of electrostatic computations are approximations based on multi-scale coarse-graining and parallelization across multiple processors. This paper demonstrates that for the computation of electrostatic surface potential, these two techniques can be combined to deliver significantly greater speed-up than either one separately, something that is in general not always possible. Specifically, the electrostatic potential computation, using an analytical linearized Poisson-Boltzmann (ALPB) method, is approximated using the hierarchical charge partitioning (HCP) multi-scale method, and parallelized on an ATI Radeon 4870 graphical processing unit (GPU). The implementation delivers a combined 934-fold speed-up for a 476,040 atom viral capsid, compared to an equivalent non-parallel implementation on an Intel E6550 CPU without the approximation. This speed-up is significantly greater than the 42-fold speed-up for the HCP approximation alone or the 182-fold speed-up for the GPU alone. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  7. Accelerating Electrostatic Surface Potential Calculation with Multiscale Approximation on Graphics Processing Units

    Science.gov (United States)

    Anandakrishnan, Ramu; Scogland, Tom R. W.; Fenley, Andrew T.; Gordon, John C.; Feng, Wu-chun; Onufriev, Alexey V.

    2010-01-01

    Tools that compute and visualize biomolecular electrostatic surface potential have been used extensively for studying biomolecular function. However, determining the surface potential for large biomolecules on a typical desktop computer can take days or longer using currently available tools and methods. Two commonly used techniques to speed up these types of electrostatic computations are approximations based on multi-scale coarse-graining and parallelization across multiple processors. This paper demonstrates that for the computation of electrostatic surface potential, these two techniques can be combined to deliver significantly greater speed-up than either one separately, something that is in general not always possible. Specifically, the electrostatic potential computation, using an analytical linearized Poisson Boltzmann (ALPB) method, is approximated using the hierarchical charge partitioning (HCP) multiscale method, and parallelized on an ATI Radeon 4870 graphical processing unit (GPU). The implementation delivers a combined 934-fold speed-up for a 476,040 atom viral capsid, compared to an equivalent non-parallel implementation on an Intel E6550 CPU without the approximation. This speed-up is significantly greater than the 42-fold speed-up for the HCP approximation alone or the 182-fold speed-up for the GPU alone. PMID:20452792

  8. A theoretical study on the effect of piezoelectric charges on the surface potential and surface depletion region of ZnO nanowires

    International Nuclear Information System (INIS)

    Purahmad, Mohsen; Stroscio, Michael A; Dutta, Mitra

    2013-01-01

    The electrostatic potential and depletion width in piezoelectric semiconductor nanowires are derived by considering a non-depleted region and a surface depleted region and solving the Poisson equation. By determining the piezoelectric-induced charge density, in terms of equivalent density of charges, the effect of piezoelectric charges on the surface depletion region and the distributed electric potential in nanowire have been investigated. The numerical results demonstrate that the ZnO NWs with a smaller radius have a larger surface depletion region which results in a stronger surface potential and depletion region perturbation by induced piezoelectric charges. (paper)

  9. Effects of photovoltaic module soiling on glass surface resistance and potential-induced degradation

    DEFF Research Database (Denmark)

    Hacke, Peter; Burton, Patrick; Hendrickson, Alexander

    2015-01-01

    The sheet resistance of three soil types (Arizona road dust, soot, and sea salt) on glass were measured by the transmission line method as a function of relative humidity (RH) between 39% and 95% at 60°C. Sea salt yielded a 3.5 orders of magnitude decrease in resistance on the glass surface when ...

  10. Current Options for Measuring the Surface Temperature of Dairy Cattle in a Stable Technology: Review

    Directory of Open Access Journals (Sweden)

    Kateřina Švejdová

    2016-05-01

    Full Text Available Regular measurement of the body surface temperature can help to assess the health status of animals. There are many technological possibilities of contactless temperature measurement of body surface. The important thing is to find the right part of the body whose temperature will point to the first possible symptoms and immediately react to the first signs of the disease. Disagreements about how to measure body surface temperature and accuracy of the method can occur when different measures are used. We review work showing possibilities of contactless surface temperature measurements using 1 thermography, 2 electronic transponders and 3 other possibilities of measuring the body surface temperature of dairy cattle. For example, when we scan the surface temperature with the thermal imager there can operate in individual animals confounding factors such as the nature or degree of muscular coat, which may significantly affect the results.

  11. New potential for the Leitz Infinity Coordinate Measuring Machine

    CERN Document Server

    Sanz, Claude; MAINAUD DURAND , Hélène; Schneider, Jurgen; Steffens, Norbert; Morantz , Paul; Shore , Paul

    2015-01-01

    The following study is realised within the frame of the PACMAN project: a study on Particle Accelerator Components Metrology and Alignment to the Nanometre scale, which is a Marie Curie program supported by the European commission and hosted by CERN (European Organisation for Nuclear Research). The aim of this program is to develop and build a pre-alignment bench on which each component is aligned to the required level in one single step using a stretched wire. During the operation, the centre of the stretched wire is aligned with the magnetic axis of the magnet. Then, the position of the wire is measured to the highest possible accuracy using a 3D Coordinate Measuring Machine (CMM) Leitz PMM-C Infinity from HEXAGON Metrology. The research described in this paper is two-fold: on one hand we apply a strong magnetic field to the head of the CMM and evaluate its influence on the measurement accuracy; on the other hand we measure the position

  12. Potential of energy efficiency measures in the world steel industry.

    NARCIS (Netherlands)

    Galama, Tjebbe

    2013-01-01

    SUMMARY The world steel industry plays a major role in energy use and Greenhouse Gas (GHG) emissions now and in the future. Implementing energy efficiency measures is among one of the most cost-effective investments that the industry could make in improv

  13. Energy and Momentum Relaxation Times of 2D Electrons Due to Near Surface Deformation Potential Scattering

    Science.gov (United States)

    Pipa, Viktor; Vasko, Fedor; Mitin, Vladimir

    1997-03-01

    The low temperature energy and momentum relaxation rates of 2D electron gas placed near the free or clamped surface of a semi-infinit sample are calculated. To describe the electron-acoustic phonon interaction with allowance of the surface effect the method of elasticity theory Green functions was used. This method allows to take into account the reflection of acoustic waves from the surface and related mutual conversion of LA and TA waves. It is shown that the strength of the deformation potential scattering at low temperatures substantially depends on the mechanical conditions at the surface: relaxation rates are suppressed for the free surface while for the rigid one the rates are enhanced. The dependence of the conductivity on the distance between the 2D layer and the surface is discussed. The effect is most pronounced in the range of temperatures 2 sl pF < T < (2 hbar s_l)/d, where pF is the Fermi momentum, sl is the velocity of LA waves, d is the width of the quantum well.

  14. Bohm potential effect on the propagation of electrostatic surface wave in semi-bounded quantum plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Myoung-Jae [Department of Physics, Hanyang University, Seoul 04763 (Korea, Republic of); Research Institute for Natural Sciences, Hanyang University, Seoul 04763 (Korea, Republic of); Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr [Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 15588 (Korea, Republic of); Department of Electrical and Computer Engineering, MC 0407, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0407 (United States)

    2017-02-12

    High frequency electrostatic wave propagation in a dense and semi-bounded electron quantum plasma is investigated with consideration of the Bohm potential. The dispersion relation for the surface mode of quantum plasma is derived and numerically analyzed. We found that the quantum effect enhances the frequency of the wave especially in the high wave number regime. However, the frequency of surface wave is found to be always lower than that of the bulk wave for the same quantum wave number. The group velocity of the surface wave for various quantum wave number is also obtained. - Highlights: • High frequency electrostatic wave propagation is investigated in a dense semi-bounded quantum plasma. • The dispersion relation for the surface mode of quantum plasma is derived and numerically analyzed. • The quantum effect enhances the frequency of the wave especially in the high wave number regime. • The frequency of surface wave is found to be always lower than that of the bulk wave. • The group velocity of the surface wave for various quantum wave number is also obtained.

  15. Potential energy surfaces for alkali plus noble gas pairs: a systematic comparison

    Science.gov (United States)

    Blank, L. Aaron; Kedziora, Gary S.; Weeks, David E.

    2010-02-01

    Optically Pumped Alkali Lasers (OPAL) involve interactions of alkali atoms with a buffer gas typically consisting of a noble gas together with C2H4. Line broadening mechanisms are of particular interest because they can be used to match a broad optical pumping source with relatively narrow alkali absorption spectra. To better understand the line broadening processes at work in OPAL systems we focus on the noble gas collisional partners. A matrix of potential energy surfaces (PES) has been generated at the multi-configurational self consistent field (MCSCF) level for M + Ng, where M=Li, Na, K, Rb, Cs and Ng=He, Ne, Ar. The PES include the X2Σ ground state surface and the A2II, B2Σ excited state surfaces. In addition to the MCSCF surfaces, PES for Li+He have been calculated at the multi-reference singles and doubles configuration interaction (MRSDCI) level with spin-orbit splitting effects included. These surfaces provide a way to check the qualitative applicability of the MCSCF calculations. They also exhibit the avoided crossing between the B2Σ and A2II1/2 surfaces that is partially responsible for collision induced relaxation from the 2P3/2 to the 2P1/2 atomic levels.

  16. Measurement of the surface susceptibility and the surface conductivity of atomically thin by spectroscopic ellipsometry

    KAUST Repository

    Jayaswal, Gaurav; Dai, Zhenyu; Zhang, Xixiang; Bagnarol, Mirko; Martucci, Alessandro; Merano, Michele

    2017-01-01

    We show how to correctly extract from the ellipsometric data the surface susceptibility and the surface conductivity that describe the optical properties of monolayer $\\rm MoS_2$. Theoretically, these parameters stem from modelling a single-layer two-dimensional crystal as a surface current, a truly two-dimensional model. Currently experimental practice is to consider this model equivalent to a homogeneous slab with an effective thickness given by the interlayer spacing of the exfoliating bulk material. We prove that the error in the evaluation of the surface susceptibility of monolayer $\\rm MoS_2$, owing to the use of the slab model, is at least 10% or greater, a significant discrepancy in the determination of the optical properties of this material.

  17. Measurement of the surface susceptibility and the surface conductivity of atomically thin by spectroscopic ellipsometry

    KAUST Repository

    Jayaswal, Gaurav

    2017-10-01

    We show how to correctly extract from the ellipsometric data the surface susceptibility and the surface conductivity that describe the optical properties of monolayer $\\ m MoS_2$. Theoretically, these parameters stem from modelling a single-layer two-dimensional crystal as a surface current, a truly two-dimensional model. Currently experimental practice is to consider this model equivalent to a homogeneous slab with an effective thickness given by the interlayer spacing of the exfoliating bulk material. We prove that the error in the evaluation of the surface susceptibility of monolayer $\\ m MoS_2$, owing to the use of the slab model, is at least 10% or greater, a significant discrepancy in the determination of the optical properties of this material.

  18. Measurement noise of a point autofocus surface topography instrument

    DEFF Research Database (Denmark)

    Feng, Xiaobing; Quagliotti, Danilo; Maculotti, Giacomo

    Optical instruments for areal topography measurement can be especially sensitive to noise when scanning is required. Such noise has different sources, including those internally generated and external sources from the environment.......Optical instruments for areal topography measurement can be especially sensitive to noise when scanning is required. Such noise has different sources, including those internally generated and external sources from the environment....

  19. Study of clean and ion bombardment damaged silver single crystal surfaces by work function measurements

    International Nuclear Information System (INIS)

    Chelvayohan, N.

    1982-06-01

    Work function values of the (110), (100) and (111) faces of silver single crystal were measured by the photoelectric emission method and found to be 4.14 +- 0.04 eV, 4.22 +-0.04 eV and 4.46 +- 0.02 eV respectively. Oxygen adsorption on the faces were studied by surface potential measurement. Strong oxygen adsorption was observed on (110) and (100) faces, whereas the (111) face was found to be inert for oxygen adsorption. Oxygen adsorption on the (111) face damaged by argon ion bombardment was also investigated. The above results were compared with those of early reported work function and oxygen adsorption values. (U.K.)

  20. Pure and Oxidized Copper Materials as Potential Antimicrobial Surfaces for Spaceflight Activities

    Science.gov (United States)

    Hahn, C.; Hans, M.; Hein, C.; Mancinelli, R. L.; Mücklich, F.; Wirth, R.; Rettberg, P.; Hellweg, C. E.; Moeller, R.

    2017-12-01

    Microbial biofilms can lead to persistent infections and degrade a variety of materials, and they are notorious for their persistence and resistance to eradication. During long-duration space missions, microbial biofilms present a danger to crew health and spacecraft integrity. The use of antimicrobial surfaces provides an alternative strategy for inhibiting microbial growth and biofilm formation to conventional cleaning procedures and the use of disinfectants. Antimicrobial surfaces contain organic or inorganic compounds, such as antimicrobial peptides or copper and silver, that inhibit microbial growth. The efficacy of wetted oxidized copper layers and pure copper surfaces as antimicrobial agents was tested by applying cultures of Escherichia coli and Staphylococcus cohnii to these metallic surfaces. Stainless steel surfaces were used as non-inhibitory control surfaces. The production of reactive oxygen species and membrane damage increased rapidly within 1 h of exposure on pure copper surfaces, but the effect on cell survival was negligible even after 2 h of exposure. However, longer exposure times of up to 4 h led to a rapid decrease in cell survival, whereby the survival of cells was additionally dependent on the exposed cell density. Finally, the release of metal ions was determined to identify a possible correlation between copper ions in suspension and cell survival. These measurements indicated a steady increase of free copper ions, which were released indirectly by cells presumably through excreted complexing agents. These data indicate that the application of antimicrobial surfaces in spaceflight facilities could improve crew health and mitigate material damage caused by microbial contamination and biofilm formation. Furthermore, the results of this study indicate that cuprous oxide layers were superior to pure copper surfaces related to the antimicrobial effect and that cell density is a significant factor that influences the time dependence of