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Sample records for monomer density profile

  1. Density limit in ASDEX discharges with peaked density profiles

    International Nuclear Information System (INIS)

    Staebler, A.; Niedermeyer, H.; Loch, R.; Mertens, V.; Mueller, E.R.; Soeldner, F.X.; Wagner, F.

    1989-01-01

    Results concerning the density limit in OH and NI-heated ASDEX discharges with the usually observed broad density profiles have been reported earlier: In ohmic discharges with high q a (q-cylindrical is used throughout this paper) the Murakami parameter (n e R/B t ) is a good scaling parameter. At the high densities edge cooling is observed causing the plasma to shrink until an m=2-instability terminates the discharge. When approaching q a =2 the density limit is no longer proportional to I p ; a minimum exists in n e,max (q a ) at q a ∼2.15. With NI-heating the density limit increases less than proportional to the heating power; the behaviour during the pre-disruptive phase is rather similar to the one of OH discharges. There are specific operating regimes on ASDEX leading to discharges with strongly peaked density profiles: the improved ohmic confinement regime, counter neutral injection, and multipellet injection. These regimes are characterized by enhanced energy and particle confinement. The operational limit in density for these discharges is, therefore, of great interest having furthermore in mind that high central densities are favourable in achieving high fusion yields. In addition, further insight into the mechanisms of the density limit observed in tokamaks may be obtained by comparing plasmas with rather different density profiles at their maximum attainable densities. 7 refs., 2 figs

  2. Use of Monomer Fraction Data in the Parametrization of Association Theories

    DEFF Research Database (Denmark)

    Kontogeorgis, Georgios; Tsivintzelis, Ioannis; von Solms, Nicolas

    2010-01-01

    the monomer fraction of hydrogen bonding compounds and their mixtures. Monomer fraction data are obtained from spectroscopic measurements and they are available for a few compounds such as pure water and alcohols as well as for some alcohol–alkane and similar mixtures. These data are useful...... “improved” model parameters can be obtained if monomer fraction data are included in the parameter estimation together with vapor pressures and liquid densities. The expression “improved” implies parameters which can represent several pure compound properties as well as monomer fraction data for pure......, liquid densities and monomer fractions of water and alcohols. The 4C scheme is the best choice for water, while for methanol there is small difference between the 2B and 3B association schemes....

  3. The virialization density of peaks with general density profiles under spherical collapse

    OpenAIRE

    Rubin, Douglas; Loeb, Abraham

    2013-01-01

    We calculate the non-linear virialization density, $\\Delta_c$, of halos under spherical collapse from peaks with an arbitrary initial and final density profile. This is in contrast to the standard calculation of $\\Delta_c$ which assumes top-hat profiles. Given our formalism, the non-linear halo density can be calculated once the shape of the initial peak's density profile and the shape of the virialized halo's profile are provided. We solve for $\\Delta_c$ for halos in an Einstein de-Sitter an...

  4. Computational studies at the density functional theory (DFT) level about the surface functionalization of hexagonal monolayers by chitosan monomer

    Science.gov (United States)

    Ebrahimi, Javad; Ahangari, Morteza Ghorbanzadeh; Jahanshahi, Mohsen

    2018-05-01

    Theoretical investigations based on density functional theory have been carried out to understand the underlying interactions between the chitosan monomer and several types of hexagonal monolayers consisting of pristine and defected graphene and boron-nitride nanosheets. Based on the obtained results, it was found that the type of the interaction for all the systems is of non-covalent nature and the chitosan monomer physically interacts with the surface of mentioned nanostructures. The interaction strength was evaluated by calculating the adsorption energies for the considered systems and it was found that the adsorption of chitosan monomer accompanies by the release of about -0.67 and -0.66 eV energy for pristine graphene and h-BN monolayer, respectively. The role of structural defect has also been considered by embedding a Stone-Wales defect within the structure of mentioned monolayers and it was found that the introduced defect enhances the interactions between the chitosan monomer and nanostructures. The role of dispersion interactions has also been taken into account and it was found that these long-range interactions play the dominating role in the attachment of chitosan monomer onto the graphene sheet, while having strong contribution together with the electrostatic interactions for the stabilization of chitosan onto the surface of h-BN monolayer. For all the cases, the adsorption of chitosan monomer did not change the inherent electronic properties of the nanostructures based on the results of charge transfer analysis and energy gap calculations. The findings of the present work would be very useful in future investigations to explore the potential applications of these hybrid materials in materials science and bio-related fields.

  5. The mutual diffusion coefficient for (meth)acrylate monomers as determined with a nuclear microprobe

    International Nuclear Information System (INIS)

    Leewis, Christian M.; Mutsaers, Peter H.A.; Jong, Arthur M. de; Ijzendoorn, Leo J. van; Voigt, Martien J.A. de; Ren, Min Q.; Watt, Frank; Broer, Dirk J.

    2004-01-01

    The value of the mutual diffusion coefficient D V of two acrylic monomers is determined with nuclear microprobe measurements on a set of polymer films. These films have been prepared by allowing the monomers to diffuse into each other for a certain time and subsequently applying fast ultraviolet photo-polymerization, which freezes the concentration profile. The monomer diffusion profiles are studied with a scanning 2.1 MeV proton microprobe. Each monomer contains a marker element, e.g., Cl and Si, which are easily detected with proton induced x-ray emission. From the diffusion profiles, it is possible to determine the mutual diffusion coefficient. The mutual diffusion coefficient is dependent of concentration, which is concluded from the asymmetry in the Cl- and Si-profiles. A linear dependence of the mutual diffusion coefficient on the composition is used as a first order approximation. The best fits are obtained for a value of b=(0.38±0.15), which is the ratio of the diffusion coefficient of 1,3-bis(3-methacryloxypropyl)-1, 1,3,3-tetramethyldisiloxane in pure 2-chloroethyl acrylate and the diffusion coefficient of 2-chloroethyl acrylate in pure 1,3-bis(3-methacryloxypropyl)-1,1,3,3-tetramethyldisiloxane. Under the assumption of a linear dependence of the mutual diffusion coefficient D V on monomer composition, it follows that D V =(2.9±0.6)·10 -10 m 2 /s at a 1:1 monomer ratio. With Flory-Huggins expressions for the monomer chemical potentials, one can derive approximate values for the individual monomer diffusion coefficients

  6. Radiation Induced Crosslinking of Polyethylene in the Presence of Bifunctional Vinyl Monomers

    DEFF Research Database (Denmark)

    Joshi, M. S.; Singer, Klaus Albert Julius; Silverman, J.

    1977-01-01

    Several reports have been published showing that the radiation induced grafting of bifunctional vinyl monomers to low density polyethylene results in a product with an unusually high density of crosslinks. The same grafting reactions are shown to reduce the incipient gel dose by more than a factor...... of fifty. This paper is concerned with the apparent crosslinking produced by the radiation grafting of two monomers to polyethylene: acrylic acid and acrylonitrile....

  7. Do CAD/CAM dentures really release less monomer than conventional dentures?

    Science.gov (United States)

    Steinmassl, Patricia-Anca; Wiedemair, Verena; Huck, Christian; Klaunzer, Florian; Steinmassl, Otto; Grunert, Ingrid; Dumfahrt, Herbert

    2017-06-01

    Computer-aided design (CAD)/computer-aided manufacturing (CAM) dentures are assumed to have more favourable material properties than conventionally fabricated dentures, among them a lower methacrylate monomer release. The aim of this study was to test this hypothesis. CAD/CAM dentures were generated from ten different master casts by using four different CAD/CAM systems. Conventional, heat-polymerised dentures served as control group. Denture weight and volume were measured; the density was calculated, and the denture surface area was assessed digitally. The monomer release after 7 days of water storage was measured by high-performance liquid chromatography. Whole You Nexteeth and Wieland Digital Dentures had significantly lower mean volume and weight than conventional dentures. Baltic Denture System and Whole You Nexteeth had a significantly increased density. Baltic Denture System had a significantly smaller surface area. None of the CAD/CAM dentures released significantly less monomer than the control group. All tested dentures released very low amounts of methacrylate monomer, but not significantly less than conventional dentures. A statistically significant difference might nevertheless exist in comparison to other, less recommendable denture base materials, such as the frequently used autopolymerising resins. CAD/CAM denture fabrication has numerous advantages. It enables the fabrication of dentures with lower resin volume and lower denture weight. Both could increase the patient comfort. Dentures with higher density might exhibit more favourable mechanical properties. The hypothesis that CAD/CAM dentures release less monomer than conventional dentures could, however, not be verified.

  8. Investigation on physical behavior of styrene wood-polymer in different concentrations of monomer

    Directory of Open Access Journals (Sweden)

    maryam ghorbani

    2016-09-01

    Full Text Available This research was conducted to study the effect of different concentrations of styrene lumen monomer on the physical properties of beech wood. Physical test samples were prepared according to ASTM-D1037 standard and treated with vacuum-pressure method at five concentration levels; 0, 40, 60, 80 and 100 percent of soluble monomer. For polymerization, treated samples were heated in oven for two 24-hour period at 90 and 103ºC respectively. Monomer and polymer absorption, density variation, water absorption, swelling and anti-swelling efficiency (ASE were determined. According to the results, Monomer and polymer absorption were increment by monomer concentration increase, and they were reported 38.2% and 26% in highest level. With polymer absorption enhancement, density of wood increased from 0/63g/cm³ in control to 0/91g/cm³ in the highest monomer concentration level that reduces pores in wood-polymer structure. Absorbed polymer enhancement decreased hydrophilicity and dimensional changes of treated samples, so that water absorption and swelling volume of the samples saturated with 100% concentration of monomer were decreased 64% and 45.3% after the longest immersion time. Highest Anti-swelling efficiency of Styrene-saturated samples was determined 56.15% in the maximum concentration level of treatment.

  9. Current density profile evolution in JET

    International Nuclear Information System (INIS)

    Stubberfield, P.M.; Balet, B.; Campbell, D.; Challis, C.D.; Cordey, J.G.; O'Rourke, J.; Hammett, G.; Schmidt, G.L.

    1989-01-01

    Simulation studies have been made of the current density profile evolution in discharges where the bootstrap current is expected to be significant. The changes predicted in the total current profile have been confirmed by comparison with experimental results. (author) 8 refs., 6 figs

  10. Optoelectronic and Photovoltaic Performances of Pyridine Based Monomer and Polymer Capped ZnO Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Singh, Satbir; Raj, Tilak; Singh, Amarpal; Kaur, Navneet

    2016-06-01

    The present research work describes the comparative analysis and performance characteristics of 4-pyridine based monomer and polymer capped ZnO dye-sensitized solar cells. The N, N-dimethyl-N4-((pyridine-4yl)methylene) propaneamine (4,monomer) and polyamine-4-pyridyl Schiff base (5, polymer) dyes were synthesized through one step condensation reaction between 4-pyridinecarboxaldehyde 1 and N, N-dimethylpropylamine 2/polyamine 3. Products obtained N, N-dimethyl-N4-((pyridine-4yl)methylene)propaneamine (4) and polyamine-4-pyridyl Schiff base (5) were purified and characterized using 1H, 13C NMR, mass, IR and CHN spectroscopy. Both the dyes 4 and 5 were further coated over ZnO nanoparticles and characterized using SEM, DLS and XRD analysis. Absorption profile and emission profile was monitored using fluorescence and UV-Vis absorption spectroscopy. A thick layer of these inbuilt dye linked ZnO nanoparticles of dyes (4) and (5) was pasted on one of the conductive side of ITO glass followed with a liquid electrolyte and counter electrode of the same conductive glass. Polyamine-4-pyridyl Schiff base polymer (5) decorated dye sensitized solar cell has shown better exciting photovoltaic properties in the form of short circuit current density (J(sc) = 6.3 mA/cm2), open circuit photo voltage (V(oc) = 0.7 V), fill factor (FF = 0.736) than monomer decorated dye sensitized solar cell. Polymer dye (5) based ZnO solar cell has shown a maximum solar power to electrical conversion efficiency of 3.25%, which is enhanced by 2.16% in case of monomer dye based ZnO solar cell under AM 1.5 sun illuminations.

  11. Monomers and Monomer Mixtures Used in Impregnation of Fibrous Materials

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1968-10-15

    Some important properties of monomers and polymers in relation to their use for reinforcement of fibrous materials are listed. Some monomers and their properties important in impregnation of fibrous materials are also listed. In general it is not advantageous to use a pure monomer for impregnation but rather a mixture of monomers or a mixture of a monomer and a low molecular weight polymer such as unsaturated polyester. Some of these mixtures which have been well studied in connection with WPC are listed together with some of their properties when used in WPC. Other monomer mixtures may well come in question and other monomers can probably be used. For instance, it is reported from Japan that the cheap monomer ethyleneoxide, which cannot be polymerized by gamma radiation as such, can be polymerized (in bulk) as a mixture with methylmethacrylate. Good results with WPC have generally been obtained without swelling agents but more is grafted if some swelling agent is used, and it is possible that a swelling agent might be useful in the case of fibre-boards. Solvents, plasticizers, crosslinkable natural resins, aromatic chlorinated hydrocarbons, and retardants can be added, and with their use the properties of WPC can be widely modified. For example, a chlorinated wax can act as retardant, can reduce the total dose of radiation and can increase the flame resistance simultaneously.

  12. NEW CONCEPTS AND TEST METHODS OF CURVE PROFILE AREA DENSITY IN SURFACE: ESTIMATION OF AREAL DENSITY ON CURVED SPATIAL SURFACE

    OpenAIRE

    Hong Shen

    2011-01-01

    The concepts of curve profile, curve intercept, curve intercept density, curve profile area density, intersection density in containing intersection (or intersection density relied on intersection reference), curve profile intersection density in surface (or curve intercept intersection density relied on intersection of containing curve), and curve profile area density in surface (AS) were defined. AS expressed the amount of curve profile area of Y phase in the unit containing surface area, S...

  13. Core fueling to produce peaked density profiles in large tokamaks

    International Nuclear Information System (INIS)

    Mikkelsen, D.R.; McGuire, K.M.; Schmidt, G.L.; Zweben, S.J.

    1994-06-01

    Peaking the density profile increases the usable bootstrap current and the average fusion power density; this could reduce the current drive power and increase the net output of power producing tokamaks. The use of neutral beams and pellet injection to produce peaked density profiles is assessed. We show that with radially ''hollow'' diffusivity profiles (and no particle pinch) moderately peaked density profiles can be produced by particle source profiles which are peaked off-axis. The fueling penetration requirements can therefore be relaxed and this greatly improves the feasibility of generating peaked density profiles in large tokamaks. In particular, neutral beam fueling does not require MeV particle energy. Even with beam voltages of ∼200 keV, however, exceptionally good particle confinement, τ p much-gt τ E is required to achieve net electrical power generation. In system with no power production requirement (e.g., neutron sources) neutral beam fueling should be capable of producing peaked density profiles in devices as large as ITER. Fueling systems with low energy cost per particle (such as cryogenic pellet injection) must be used in power producing tokamaks when τ p ∼ τ E . Simulations with pellet injection speeds of 7 km/sec show the peaking factor, n eo /left-angle n e right-angle, approaching 2

  14. Radiation-induced graft polymerization of amphiphilic monomers with different polymerization characteristics onto hydrophobic polysilane

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Hidenori; Iwasaki, Isao; Kunai, Yuichiro [Research Reactor Institute, Kyoto University, Asashironishi 2-1010, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Sato, Nobuhiro, E-mail: sato-n@rri.kyoto-u.ac.j [Research Reactor Institute, Kyoto University, Asashironishi 2-1010, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Matsuyama, Tomochika [Research Reactor Institute, Kyoto University, Asashironishi 2-1010, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan)

    2011-08-15

    The structures of poly(methyl-n-propylsilane) (PMPrS) amphiphilically modified through {gamma}-ray-induced graft polymerization were investigated with {sup 1}H NMR measurement. By the use of methyl methacrylate (MMA) or diethyl fumarate (DEF) as monomers for the graft polymerization, grafting yield rose with increasing total absorption dose and monomer concentrations, but decreased with increasing dose rate. This result means that grafting yield of modified PMPrS can be controlled by changing irradiation conditions. However, the number of PMMA or PDEF graft chains per PMPrS chain was estimated to be less than 1.0 by analysis of {sup 1}H NMR spectra, and this value was lower than that we had expected. To improve graft density, maleic anhydride (MAH), which is known as a non-homopolymerizable monomer in radical polymerization, was used as a monomer for grafting. As a result, high density grafting (one MAH unit for 4.2 silicon atoms) was attained. It demonstrates that the structure of {gamma}-ray-modified polysilane strongly depends on the polymerization characteristics of grafted monomers.

  15. Core fuelling to produce peaked density profiles in large tokamaks

    International Nuclear Information System (INIS)

    Mikkelsen, D.R.; McGuire, K.M.; Schmidt, G.L.; Zweben, S.J.

    1995-01-01

    Peaking the density profile increases the usable bootstrap current and the average fusion power density; this could reduce the current drive power and increase the net output of power producing tokamaks. The use of neutral beams and pellet injection to produce peaked density profiles is assessed. It is shown that with radially 'hollow' diffusivity profiles (and no particle pinch) moderately peaked density profiles can be produced by particle source profiles that are peaked off-axis. The fuelling penetration requirements can therefore be relaxed and this greatly improves the feasibility of generating peaked density profiles in large tokamaks. In particular, neutral beam fuelling does not require Megavolt particle energies. Even with beam voltages of ∼ 200 keV, however, exceptionally good particle confinement is needed to achieve net electrical power generation. The required ratio of particle to thermal diffusivities is an order of magnitude outside the range reported for tokamaks. In a system with no power production requirement (e.g., neutron sources) neutral beam fuelling should be capable of producing peaked density profiles in devices as large as ITER. Fuelling systems with low energy cost per particle - such as cryogenic pellet injection - must be used in power producing tokamaks when τ P ∼ τ E . Simulations with pellet injection speeds of 7 km/s show that the peaking factor, n e0 / e >, approaches 2. (author). 65 refs, 8 figs

  16. Thickness Evaluation of Pipeline Using Density Profile on a Radiograph

    International Nuclear Information System (INIS)

    Lee, Sung Sik; Jang, Byoung Gyu; Kim, Young H.

    2002-01-01

    The computer simulation has been done for non-insulated and insulated pipes which are vacant or half filled with liquid. The simulation results showed that the density profile on the radiography is continuous and symmetrical around the center of pipe in the case of vacant pipe. On the other hand the density profiles are not symmetrical and depend on geometrical setting for radiography in the case of half filled pipes. Finally, experimental testing on a non-insulated carbon steel pipe with artificial notches of different depth is carried out using Ir-192 and industrial film. Comparing the measured density profile on the radiograph to the calculated one, it has been shown that it is possible to evaluate thickness variation by measuring density profile on a radiograph

  17. Density profile analysis during an ELM event in ASDEX Upgrade H-modes

    International Nuclear Information System (INIS)

    Nunes, I.; Manso, M.; Serra, F.; Horton, L.D.; Conway, G.D.; Loarte, A.

    2005-01-01

    This paper reports results on measurements of the density profiles. Here we analyse the behaviour of the electron density for a set of experiments in type I ELMy H-mode discharges in ASDEX Upgrade where the plasma current, plasma density, triangularity and input power were varied. Detailed measurements of the radial extent of the perturbation on the density profiles caused by the edge localized mode (ELM) crash (ELM affected depth), the velocity of the radial propagation of the perturbation as well as the width and gradient of the density pedestal are determined. The effect of a type I ELM event on the density profiles affects the outermost 20-40% of the plasma minor radius. At the scrape-off layer (SOL) the density profile broadens while in the pedestal region the density decreases resulting in a smaller density gradient. This change in the density profile defines a pivot point around which the density profile changes. The average radial velocity at the SOL is in the range 125-150 ms -1 and approximately constant for all the density layers far from the pivot point. The width of the density pedestal is approximately constant for all the ELMy H-mode discharges analysed, with values between 2 and 3.5 cm. These results are then compared with an analytical model where the width of the density is predominantly set by ionization (neutral penetration model). The width of the density profiles for L-mode discharges is included, since L- and H-mode have different particle transport. No agreement between the experimental results and the model is found

  18. In-vitro transdentinal diffusion of monomers from adhesives.

    Science.gov (United States)

    Putzeys, Eveline; Duca, Radu Corneliu; Coppens, Lieve; Vanoirbeek, Jeroen; Godderis, Lode; Van Meerbeek, Bart; Van Landuyt, Kirsten L

    2018-06-01

    Biocompatibility of adhesives is important since adhesives may be applied on dentin near the pulp. Accurate knowledge of the quantity of monomers reaching the pulp is important to determine potential side effects. The aim of this study was to assess the transdentinal diffusion of residual monomers from dental adhesive systems using an in-vitro pulp chamber model. Dentin disks with a thickness of 300 µm were produced from human third molars. These disks were fixed between two open-ended glass tubes, representing an in-vitro pulp chamber. The etch-and-rinse adhesive OptiBond FL and the self-etch adhesive Clearfil SE Bond were applied to the dentin side of the disks, while on in the pulpal side, the glass tube was filled with 600 µL water. The transdentinal diffusion of different monomers was quantified using ultra-performance liquid chromatography-tandem mass spectrometry. The monomers HEMA, CQ, BisGMA, GPDM, 10-MDP and UDMA eluted from the dental materials and were able to diffuse through the dentin disks to a certain extent. Compounds with a lower molecular weight (uncured group: HEMA 7850 nmol and CQ 78.2 nmol) were more likely to elute and diffuse compared to monomers with a higher molecular weight (uncured group: BisGMA 0.42 nmol). When the adhesives were left uncured, diffusion was up to 10 times higher compared to the cured conditions. This in-vitro research resulted in the quantification of various monomers able to diffuse through dentin and therefore contributes to a more detailed understanding about the potential exposure of the dental pulp to monomers from dental adhesives. Biocompatibility of adhesives is important since adhesives may be applied on dentin near the pulp, where tubular density and diameter are greatest. Copyright © 2018. Published by Elsevier Ltd.

  19. Edge density profiles in high-performance JET plasmas

    International Nuclear Information System (INIS)

    Summers, D.D.R.; Viaccoz, B.; Vince, J.

    1997-01-01

    Detailed electron density profiles of the scrape-off layer in high-performance JET plasmas (plasma current, I p nbi ∝17 MW) have been measured by means of a lithium beam diagnostic system featuring high spatial resolution [Kadota (1978)[. Measurements were taken over a period of several seconds, allowing examination of the evolution of the edge profile at a location upstream from the divertor target. The data clearly show the effects of the H-mode transition - an increase in density near the plasma separatrix and a reduction in density scrape-off length. The profiles obtained under various plasma conditions are compared firstly with data from other diagnostics, located elsewhere in the vessel, and also with the predictions of an 'onion-skin' model (DIVIMP), which used, as initial parameters, data from an array of probes located in the divertor target. (orig.)

  20. Real-time feedback control of the plasma density profile on ASDEX Upgrade

    International Nuclear Information System (INIS)

    Mlynek, A.; Reich, M.; Giannone, L.; Treutterer, W.; Behler, K.; Blank, H.; Buhler, A.; Cole, R.; Eixenberger, H.; Fischer, R.; Lohs, A.; Lueddecke, K.; Merkel, R.; Neu, G.; Ryter, F.; Zasche, D.

    2011-01-01

    The spatial distribution of density in a fusion experiment is of significant importance as it enters in numerous analyses and contributes to the fusion performance. The reconstruction of the density profile is therefore commonly done in offline data analysis. In this paper, we present an algorithm which allows for density profile reconstruction from the data of the submillimetre interferometer and the magnetic equilibrium in real-time. We compare the obtained results to the profiles yielded by a numerically more complex offline algorithm. Furthermore, we present recent ASDEX Upgrade experiments in which we used the real-time density profile for active feedback control of the shape of the density profile.

  1. Electron density profile in multilayer systems

    International Nuclear Information System (INIS)

    Toekesi, K.

    2004-01-01

    Complete text of publication follows. Electron energy loss spectroscopy (EELS) has been used extensively to study the multilayer systems, where the thickness of layers are in the nanometer range. These studies has received considerable attention because of its technological interest, for example in the nanotechnology. On the most fundamental level, its importance is derived from the basic physics that is involved. One key quantities of interest is the response of a many-body system to an external perturbation: How act and how modify the interface between the solid-solid or solid-vacuum the excitations in the solid and in the vicinity of the interfaces. In this work, as a starting point of such investigations we calculated the electron density profile for multilayer systems. Our approach employs the time-dependent density functional theory (TDDFT), that is, the solution of a time-dependent Schroedinger equation in which the potential and forces are determined selfconsistently from the dynamics governed by the Schroedinger equation. We treat the problem in TDDFT at the level of the local-density approximation (LDA). Later, the comparison of experimentally obtained loss functions and the theory, based on our TDDFT calculations can provide deeper understanding of surface physics. We performed the calculations for half-infinite samples characterized by r s =1.642 and r s =1.997. We also performed the calculations for double layer systems. The substrate was characterized by r s =1.997 and the coverage by r s =1.642. Fig. 1. shows the obtained electron density profile in LDA approximation. Because of the sharp cutoff of electronic wave vectors at the Fermi surface, the densities in the interior exhibit slowly decaying Friedel oscillations. To highlight the Friedel oscillation we enlarged the electron density profile in Fig. 1a. and Fig. 1b. The work was supported by the Hungarian Scientific Research Found: OTKA No. T038016, the grant 'Bolyai' from the Hungarian Academy of

  2. Two Populations Mean-Field Monomer-Dimer Model

    Science.gov (United States)

    Alberici, Diego; Mingione, Emanuele

    2018-04-01

    A two populations mean-field monomer-dimer model including both hard-core and attractive interactions between dimers is considered. The pressure density in the thermodynamic limit is proved to satisfy a variational principle. A detailed analysis is made in the limit of one population is much smaller than the other and a ferromagnetic mean-field phase transition is found.

  3. Real-time control of the plasma density profile on ASDEX upgrade

    International Nuclear Information System (INIS)

    Mlynek, Alexander

    2010-01-01

    The tokamak concept currently is the most promising approach to future power generation by controlled thermonuclear fusion. The spatial distribution of the particle density in the toroidally confined fusion plasma is of particular importance. This thesis work therefore focuses on the question as to what extent the shape of the density profile can be actively controlled by a feedback loop in the fusion experiment ASDEX Upgrade. There are basically two essential requirements for such feedback control of the density profile, which has been experimentally demonstrated within the scope of this thesis work: On the one hand, for this purpose the density profile must be continuously calculated under real-time constraints during a plasma discharge. The calculation of the density profile is based on the measurements of a sub-millimeter interferometer, which provides the line-integrated electron density along 5 chords through the plasma. Interferometric density measurements can suffer from counting errors by integer multiples of 2π when detecting the phase difference between a probing and a reference beam. As such measurement errors have severe impact on the reconstructed density profile, one major part of this work consists in the development of new readout electronics for the interferometer, which allows for detection of such measurement errors in real-time with high reliability. A further part of this work is the design of a computer algorithm which reconstructs the spatial distribution of the plasma density from the line-integrated measurements. This algorithm has to be implemented on a computer which communicates the measured data to other computers in real-time, especially to the tokamak control system. On the other hand, a second fundamental requirement for the successful implementation of a feedback controller is the identification of at least one actuator which enables a modification of the density profile. Here, electron cyclotron resonance heating (ECRH) has been

  4. Electon density profiles of the topside ionosphere

    Directory of Open Access Journals (Sweden)

    D. Bilitza

    2002-06-01

    Full Text Available The existing uncertainties about the electron density profiles in the topside ionosphere, i.e., in the height region from h m F 2 to ~ 2000 km, require the search for new data sources. The ISIS and Alouette topside sounder satellites from the sixties to the eighties recorded millions of ionograms but most were not analyzed in terms of electron density profiles. In recent years an effort started to digitize the analog recordings to prepare the ionograms for computerized analysis. As of November 2001 about 350 000 ionograms have been digitized from the original 7-track analog tapes. These data are available in binary and CDF format from the anonymous ftp site of the National Space Science Data Center. A search site and browse capabilities on CDAWeb assist the scientific usage of these data. All information and access links can be found at http://nssdc.gsfc.nasa.gov/space/isis/isis-status. html. This paper describes the ISIS data restoration effort and shows how the digital ionograms are automatically processed into electron density profiles from satellite orbit altitude (1400 km for ISIS-2 down to the F peak. Because of the large volume of data an automated processing algorithm is imperative. The TOPside Ionogram Scaler with True height algorithm TOPIST software developed for this task is successfully scaling ~ 70% of the ionograms. An «editing process» is available to manually scale the more difficult ionograms. The automated processing of the digitized ISIS ionograms is now underway, producing a much-needed database of topside electron density profiles for ionospheric modeling covering more than one solar cycle.

  5. Atmospheric turbulence profiling with unknown power spectral density

    Science.gov (United States)

    Helin, Tapio; Kindermann, Stefan; Lehtonen, Jonatan; Ramlau, Ronny

    2018-04-01

    Adaptive optics (AO) is a technology in modern ground-based optical telescopes to compensate for the wavefront distortions caused by atmospheric turbulence. One method that allows to retrieve information about the atmosphere from telescope data is so-called SLODAR, where the atmospheric turbulence profile is estimated based on correlation data of Shack-Hartmann wavefront measurements. This approach relies on a layered Kolmogorov turbulence model. In this article, we propose a novel extension of the SLODAR concept by including a general non-Kolmogorov turbulence layer close to the ground with an unknown power spectral density. We prove that the joint estimation problem of the turbulence profile above ground simultaneously with the unknown power spectral density at the ground is ill-posed and propose three numerical reconstruction methods. We demonstrate by numerical simulations that our methods lead to substantial improvements in the turbulence profile reconstruction compared to the standard SLODAR-type approach. Also, our methods can accurately locate local perturbations in non-Kolmogorov power spectral densities.

  6. Surface density profile and surface tension of the one-component classical plasma

    International Nuclear Information System (INIS)

    Ballone, P.; Senatore, G.; Trieste Univ.; Tosi, M.P.; Oxford Univ.

    1982-08-01

    The density profile and the interfacial tension of two classical plasmas in equilibrium at different densities are evaluated in the square-density-gradient approximation. For equilibrium in the absence of applied external voltage, the profile is oscillatory in the higher-density plasma and the interfacial tension is positive. The amplitude and phase of these oscillations and the magnitude of the interfacial tension are related to the width of the background profile. Approximate representations of the equilibrium profile by matching of its asymptotic forms are analyzed. A comparison with computer simulation data and a critical discussion of a local-density theory are also presented. (author)

  7. Effect of solubility parameter of monomers on electron beam induced graft-polymerization onto polyethylene films

    International Nuclear Information System (INIS)

    Mori, Koji; Koshiishi, Kenji; Masuhara, Ken-ichi

    1991-01-01

    Electron beam induced graft-polymerization by the mutual irradiation technique of monomers with different solubility parameters δ onto low density polyethylene films (LDPE) and high density polyethylene films (HDPE) were investigated at high dose rates (25 Mrad per second). Graft-polymerization mechanisms were discussed on the basis of grafting rates, surface tensions, atomic ratios of surface by XPS, and SEM images of the grafted films. Grafting rates decreased with increasing δ of monomers, and grafting rates onto LDPE were larger than those onto HDPE. Graft chain contents on surface, which were evaluated in terms of surface tensions and atomic ratios of the surface, increased with increasing δ of monomers, and graft chain contents on surface of HDPE were higher than those of LDPE. It is assumed that mutual solubility of PE and monomers, i.e., infiltration of monomers into PE during graft-polymerization influence grafting rates and graft sites in films. In case of high mutual solubility, grafting rates were large and graft sites spread from the surface into bulk. On the other hand, in case of low mutual solubility, grafting rates were small and graft sites localized on the surface of films. (author)

  8. Reactivity of vinyl ethers and vinyl ribosides in UV-initiated free radical copolymerization with acceptor monomers.

    Science.gov (United States)

    Pichavant, Loic; Guillermain, Céline; Coqueret, Xavier

    2010-09-13

    The reactivity of various vinyl ethers and vinyloxy derivatives of ribose in the presence of diethyl fumarate or diethyl maleate was investigated for evaluating the potential of donor-acceptor-type copolymerization applied to unsaturated monomers derived from renewable feedstock. The photochemically induced polymerization of model monomer blends in the bulk state was monitored by infrared spectroscopy. The method allowed us to examine the influence of monomer pair structure on the kinetic profiles. The simultaneous consumption of both monomers was observed, supporting an alternating copolymerization mechanism. A lower reactivity of the blends containing maleates compared with fumarates was confirmed. The obtained kinetic data revealed a general correlation between the initial polymerization rate and the Hansen parameter δ(H) associated with the H-bonding aptitude of the donor monomer.

  9. Simple introduction of sulfonic acid group onto polyethylene by radiation-induced cografting of sodium styrenesulfonate with hydrophilic monomers

    International Nuclear Information System (INIS)

    Tsuneda, Satoshi; Saito, Kyoichi; Furusaki, Shintaro; Sugo, Takanobu; Makuuchi, Keizo

    1993-01-01

    The sulfonic acid (SO 3 H) group was readily introduced into a polyethylene (PE) membrane by radiation-induced cografting of sodium styrenesulfonate (SSS) with hydrophilic monomers such as acrylic acid (AAc) and hydroxyethyl methacrylate (HEMA). The density of SSS grafted onto the PE membrane was determined as a function of molar ratio of hydrophilic monomer to SSS in the monomer mixture. Immersion of the electron-beam-irradiated PE membrane into the mixture of SSS and HEMA for 5 h at 323 K provided to the SO 3 H density of 2.5 mol/kg of the H-type product

  10. Matter Density Profile Shape Effects at DUNE

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Kevin J. [Northwestern U.; Parke, Stephen J. [Fermilab

    2018-02-19

    Quantum mechanical interactions between neutrinos and matter along the path of propagation, the Wolfenstein matter effect, are of particular importance for the upcoming long-baseline neutrino oscillation experiments, specifically the Deep Underground Neutrino Experiment (DUNE). Here, we explore specifically what about the matter density profile can be measured by DUNE, considering both the shape and normalization of the profile between the neutrinos' origin and detection. Additionally, we explore the capability of a perturbative method for calculating neutrino oscillation probabilities and whether this method is suitable for DUNE. We also briefly quantitatively explore the ability of DUNE to measure the Earth's matter density, and the impact of performing this measurement on measuring standard neutrino oscillation parameters.

  11. 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

  12. Electron Density Profile Data Contains Virtual Height/Frequency Pairs from a Profile or Profiles (Composite Months) of Ionograms

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Electron Density Profile, N(h), data set contains both individual profiles and composite months. The data consist of virtual height/frequency pairs from a...

  13. Controlled grafting of vinylic monomers on polyolefins: a robust mathematical modeling approach.

    Science.gov (United States)

    Saeb, Mohammad Reza; Rezaee, Babak; Shadman, Alireza; Formela, Krzysztof; Ahmadi, Zahed; Hemmati, Farkhondeh; Kermaniyan, Tayebeh Sadat; Mohammadi, Yousef

    2017-01-01

    Experimental and mathematical modeling analyses were used for controlling melt free-radical grafting of vinylic monomers on polyolefins and, thereby, reducing the disturbance of undesired cross-linking of polyolefins. Response surface, desirability function, and artificial intelligence methodologies were blended to modeling/optimization of grafting reaction in terms of vinylic monomer content, peroxide initiator concentration, and melt-processing time. An in-house code was developed based on artificial neural network that learns and mimics processing torque and grafting of glycidyl methacrylate (GMA) typical vinylic monomer on high-density polyethylene (HDPE). Application of response surface and desirability function enabled concurrent optimization of processing torque and GMA grafting on HDPE, through which we quantified for the first time competition between parallel reactions taking place during melt processing: (i) desirable grafting of GMA on HDPE; (ii) undesirable cross-linking of HDPE. The proposed robust mathematical modeling approach can precisely learn the behavior of grafting reaction of vinylic monomers on polyolefins and be placed into practice in finding exact operating condition needed for efficient grafting of reactive monomers on polyolefins.

  14. Vibrational study and Natural Bond Orbital analysis of serotonin in monomer and dimer states by density functional theory

    Science.gov (United States)

    Borah, Mukunda Madhab; Devi, Th. Gomti

    2018-06-01

    The vibrational spectral analysis of Serotonin and its dimer were carried out using the Fourier Transform Infrared (FTIR) and Raman techniques. The equilibrium geometrical parameters, harmonic vibrational wavenumbers, Frontier orbitals, Mulliken atomic charges, Natural Bond orbitals, first order hyperpolarizability and some optimized energy parameters were computed by density functional theory with 6-31G(d,p) basis set. The detailed analysis of the vibrational spectra have been carried out by computing Potential Energy Distribution (PED, %) with the help of Vibrational Energy Distribution Analysis (VEDA) program. The second order delocalization energies E(2) confirms the occurrence of intramolecular Charge Transfer (ICT) within the molecule. The computed wavenumbers of Serotonin monomer and dimer were found in good agreement with the experimental Raman and IR values.

  15. A SURVEY OF CORONAL CAVITY DENSITY PROFILES

    International Nuclear Information System (INIS)

    Fuller, J.; Gibson, S. E.

    2009-01-01

    Coronal cavities are common features of the solar corona that appear as darkened regions at the base of coronal helmet streamers in coronagraph images. Their darkened appearance indicates that they are regions of lowered density embedded within the comparatively higher density helmet streamer. Despite interfering projection effects of the surrounding helmet streamer (which we refer to as the cavity rim), Fuller et al. have shown that under certain conditions it is possible to use a Van de Hulst inversion of white-light polarized brightness (pB) data to calculate the electron density of both the cavity and cavity rim plasma. In this article, we apply minor modifications to the methods of Fuller et al. in order to improve the accuracy and versatility of the inversion process, and use the new methods to calculate density profiles for both the cavity and cavity rim in 24 cavity systems. We also examine trends in cavity morphology and how departures from the model geometry affect our density calculations. The density calculations reveal that in all 24 cases the cavity plasma has a flatter density profile than the plasma of the cavity rim, meaning that the cavity has a larger density depletion at low altitudes than it does at high altitudes. We find that the mean cavity density is over four times greater than that of a coronal hole at an altitude of 1.2 R sun and that every cavity in the sample is over twice as dense as a coronal hole at this altitude. Furthermore, we find that different cavity systems near solar maximum span a greater range in density at 1.2 R sun than do cavity systems near solar minimum, with a slight trend toward higher densities for systems nearer to solar maximum. Finally, we found no significant correlation of cavity density properties with cavity height-indeed, cavities show remarkably similar density depletions-except for the two smallest cavities that show significantly greater depletion.

  16. Experimental profile evolution of a high-density field-reversed configuration

    International Nuclear Information System (INIS)

    Ruden, E. L.; Zhang, Shouyin; Intrator, T. P.; Wurden, G. A.

    2006-01-01

    A field-reversed configuration (FRC) gains angular momentum over time, eventually resulting in an n=2 rotational instability (invariant under rotation by π) terminating confinement. To study this, a laser interferometer probes the time history of line integrated plasma density along eight chords of the high-density (∼10 17 cm -3 ) field-reversed configuration experiment with a liner. Abel and tomographic inversions provide density profiles during the FRC's azimuthally symmetric phase, and over a period when the rotational mode has saturated and rotates with a roughly fixed profile, respectively. During the latter part of the symmetric phase, the FRC approximates a magnetohydrodynamic (MHD) equilibrium, allowing the axial magnetic-field profile to be calculated from pressure balance. Basic FRC properties such as temperature and poloidal flux are then inferred. The subsequent two-dimensional n=2 density profiles provide angular momentum information needed to set bounds on prior values of the stability relevant parameter α (rotational to ion diamagnetic drift frequency ratio), in addition to a view of plasma kinematics useful for benchmarking plasma models of higher order than MHD

  17. Stationary density profiles in the Alcator C-mod tokamak

    International Nuclear Information System (INIS)

    Kesner, J.; Ernst, D.; Hughes, J.; Mumgaard, R.; Shiraiwa, S.; Whyte, D.; Scott, S.

    2012-01-01

    In the absence of an internal particle source, plasma turbulence will impose an intrinsic relationship between an inwards pinch and an outwards diffusion resulting in a stationary density profile. The Alcator C-mod tokamak utilizes RF heating and current drive so that fueling only occurs in the vicinity of the separatrix. Discharges that transition from L-mode to I-mode are seen to maintain a self-similar stationary density profile as measured by Thomson scattering. For discharges with negative magnetic shear, an observed rise of the safety factor in the vicinity of the magnetic axis appears to be accompanied by a decrease of electron density, qualitatively consistent with the theoretical expectations.

  18. Monomers capable of forming four hydrogen bridges and supramolecular polymers formed by copolymerization of these monomers with regular monomers

    NARCIS (Netherlands)

    2004-01-01

    The invention relates to the synthesis of polymers containing self-complementary quadruple hydrogen groups by copolymerizing monomers containing a quadruple hydrogen bonding group with one or more monomers of choice. The resulting polymers show unique new characteristics due to the presence of

  19. Facile synthesis of allyl resinate monomer in an aqueous solution ...

    Indian Academy of Sciences (India)

    The synthesized monomer product appeared as a viscous liquid, with a viscosity of 460 mPa·s at 25◦C and a density of ... ated under high reaction temperature, which reduces the ... The use of DMF as an organic solvent also comes with.

  20. Response of temperature and density profiles to heat deposition profile and its impact on global scaling in LHD

    International Nuclear Information System (INIS)

    Yamada, H.

    2002-01-01

    Significant density dependence of the energy confinement time as described in the ISS95 scaling has been demonstrated in the extended parameter regimes in LHD. However, recent experiments have indicated that this density dependence is lost at a certain density under specific conditions. This paper discusses the cause of this saturation and related characteristics of anomalous transport. The saturation of the energy confinement time is observed in the density ramp-up phase of NBI heated plasmas. In contrast to the global energy confinement time, the local heat conduction coefficient still indicates the temperature dependence which is a companion to the density dependence of the energy confinement time. The apparent contradiction between the global confinement and the local transport can be attributed to the change of the heat deposition profile. Through this study, the response of temperature and density profiles to the heat deposition profile is highlighted, which is contrasted to the concept of stiffness or profile consistency observed in tokamaks. The major anomalous transport models based on ITG/TEM and interchange/ballooning modes are assessed. (author)

  1. Advances in the density profile evaluation from broadband reflectometry on ASDEX upgrade

    International Nuclear Information System (INIS)

    Varela, P.; Manso, M.; Conway, G.

    2001-01-01

    The high temporal and spatial resolutions provided by broadband microwave reflectometry make it an attractive diagnostic technique to measure the density profile in fusion plasmas. However, great problems have been encountered due to the plasma turbulence that difficult, and sometimes prevent, the routine evaluation of density profiles. Advanced broadband systems employ ultra-fast sweeping in an attempt to perform the profile measurement in a time window smaller than the temporal scale of the main plasma fluctuations but this is not sufficient. Indeed, abrupt plasma movements and/or spatial turbulence always affect the reflectometry signals, as shown by numerical studies (with both one- and two-dimensional codes), for the case of ultra-fast sweeping and pulse radar systems. For this reason not only the system performance is important but the software tools also play a crucial role for reflectometry to become a standard density profile diagnostic. Here we present the recent advances towards automatic evaluation of density profiles from broadband reflectometry on ASDEX Upgrade. For regimes with moderate levels of plasma turbulence, density profiles are obtained from single reflectometry samples (temporal resolution of 20 μs), and for higher turbulence levels average profiles are obtained from bursts of ultra-fast (20 μs), closely spaced (10 μs) sweeps. This method improved the accuracy and reliability of density profiles, which can now be obtained automatically from the edge to the bulk plasma - using reflectometry alone - in most plasma regimes of ASDEX Upgrade. New data processing capability has been implemented that allows the profiles to be available to the end-users 10-12 minutes after each discharge. These developments were possible due to the flexibility and high performance of the control and data acquisition systems and to the large number of measurements that can be performed with the diagnostic during each discharge (720 profiles both on the low- and

  2. Control-oriented modeling of the plasma particle density in tokamaks and application to real-time density profile reconstruction

    NARCIS (Netherlands)

    Blanken, T.C.; Felici, F.; Rapson, C.J.; de Baar, M.R.; Heemels, W.P.M.H.

    2018-01-01

    A model-based approach to real-time reconstruction of the particle density profile in tokamak plasmas is presented, based on a dynamic state estimator. Traditionally, the density profile is reconstructed in real-time by solving an ill-conditioned inversion problem using a measurement at a single

  3. Electron number density profiles derived from radio occultation on the CASSIOPE spacecraft

    DEFF Research Database (Denmark)

    Shume, E. B.; Vergados, P.; Komjathy, A.

    2017-01-01

    This paper presents electron number density profiles derived from high resolution Global Positioning System (GPS) radio occultation (RO) observations performed using the Enhanced Polar Outflow Probe (e-POP) payload on the high inclination CAScade, Smallsat and IOnospheric Polar Explorer (CASSIOPE...... good agreement with density profiles estimated from ionosonde data, measured over nearby stations to the latitude and longitude of the RO tangent points, (2) in good agreement with density profiles inferred from GPS RO measured by the Constellation Observing System for Meteorology, Ionosphere...

  4. Effects of monomer shape on the formation of aggregates from a power law monomer distribution

    International Nuclear Information System (INIS)

    Perry, J; Kimery, J; Matthews, L S; Hyde, T W

    2013-01-01

    The coagulation of dust aggregates is an important process in many physical systems such as the Earth's upper atmosphere, comet tails and protoplanetary discs. Numerical models which study the aggregation in these systems typically involve spherical monomers. There is evidence, however, via the polarization of sunlight in the interstellar medium, as well as optical and LIDAR observations of high-altitude particles in Earth's atmosphere (70–100 km), which indicate that dust monomers may not necessarily be spherical. This study investigates the influence of different ellipsoidal monomer shapes on the morphology of aggregates given various distributions of monomer sizes. Populations of aggregates are grown from a single monomer using a combination of ballistic particle–cluster aggregation and ballistic cluster–cluster aggregation regimes incorporating the rotation of monomers and aggregates. The resulting structures of the aggregates are then compared via the compactness factor, geometric cross-section and friction time. (paper)

  5. Electron density profile measurements by microwave reflectometry on Tore Supra

    International Nuclear Information System (INIS)

    Clairet, F.; Paume, M.; Chareau, J.M.

    1995-01-01

    A proposal is presented developing reflectometry diagnostic for electron density profile measurements as routine diagnostic without manual intervention as achieved at JET. Since density fluctuations seriously perturb the reflected signal and the measurement of the group delay, a method is described to overcome the irrelevant results with the help of an adaptive filtering technique. Accurate profiles are estimated for about 70% of the shots. (author) 3 refs.; 6 figs

  6. CO2 laser diagnostics for measurements of the plasma density profile and plasma density fluctuations on LHD

    International Nuclear Information System (INIS)

    Vyacheslavov, L.N.; Tanaka, K.; Kawahata, K.

    2001-04-01

    A CO 2 laser based diagnostics complimentary to the existing FIR interferometer is proposed. It combines interferometry for plasma density profile measurement under conditions of large density gradients, and both imaging and scattering techniques for observation of plasma fluctuations. Two-colour interferometer with a slablike probe beam and a single multichannel linear detector array provide observation of plasma density profile and density fluctuations at two locations along the probe beam. Basic characteristics of the diagnostics are considered as well as some effects that include dispersion and are critical for two colour imaging technique. The results of the bench-top experiments with the prototype of the interferometer are presented. (author)

  7. Scattering Studies of Hydrophobic Monomers in Liposomal Bilayers: An Expanding Shell Model of Monomer Distribution

    International Nuclear Information System (INIS)

    Richter, Andrew; Dergunov, Sergey; Ganus, Bill; Thomas, Zachary; Pingali, Sai Venkatesh; Urban, Volker S.; Liu, Yun; Porcar, Lionel; Pinkhassik, Eugene

    2011-01-01

    Hydrophobic monomers partially phase separate from saturated lipids when loaded into lipid bilayers in amounts exceeding a 1:1 monomer/lipid molar ratio. This conclusion is based on the agreement between two independent methods of examining the structure of monomer-loaded bilayers. Complete phase separation of monomers from lipids would result in an increase in bilayer thickness and a slight increase in the diameter of liposomes. A homogeneous distribution of monomers within the bilayer would not change the bilayer thickness and would lead to an increase in the liposome diameter. The increase in bilayer thickness, measured by the combination of small-angle neutron scattering (SANS) and small-angle X-ray scattering (SAXS), was approximately half of what was predicted for complete phase separation. The increase in liposome diameter, measured by dynamic light scattering (DLS), was intermediate between values predicted for a homogeneous distribution and complete phase separation. Combined SANS, SAXS, and DLS data suggest that at a 1.2 monomer/lipid ratio approximately half of the monomers are located in an interstitial layer sandwiched between lipid sheets. These results expand our understanding of using self-assembled bilayers as scaffolds for the directed covalent assembly of organic nanomaterials. In particular, the partial phase separation of monomers from lipids corroborates the successful creation of nanothin polymer materials with uniform imprinted nanopores. Pore-forming templates do not need to span the lipid bilayer to create a pore in the bilayer-templated films.

  8. Estimation and display of beam density profiles

    Energy Technology Data Exchange (ETDEWEB)

    Dasgupta, S; Mukhopadhyay, T; Roy, A; Mallik, C

    1989-03-15

    A setup in which wire-scanner-type beam-profile monitor data are collected on-line in a nuclear data-acquisition system has been used and a simple algorithm for estimation and display of the current density distribution in a particle beam is described.

  9. Current density profile inside q=1 on Tore Supra

    International Nuclear Information System (INIS)

    Joffrin, E.; Desgranges, C.; Sabot, R.; Dubois, M.A.

    1995-01-01

    The Tore Supra polarimeter used to measure the poloidal field distribution is described. The current density profiles are computed in two different ways using the interferometric and polarimetric data in conjunction with the magnetic data and the location of the inversion radius determined by the soft X-ray camera. The current density inside the q=1 surface is investigated for normal and monster sawteeth. Its variation are also measured by the polarimeter and compared with that predicted by the current diffusion equation assuming complete reconnection. Finally, the safety factor profile is compared with that obtained with the striation data of the pellet ablation. The results of the evolution of the q profile during sawteeth are in good agreement with those obtained in other devices. (author) 9 refs.; 4 figs

  10. Density profile evolution during dynamic processes in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Nunes, I.; Santos, J.; Salzedas, F.; Manso, M.; Serra, F.; Conway, G.D.; Horton, L.D.; Neuhauser, J.; Suttrop, W.

    2005-01-01

    The current understanding of edge localized modes (ELMs) and the trigger of major disruptions is largely based on phenomenology. The need to better understand the processes underlying these phenomena requires high temporal and spatial resolution diagnostics. Fast diagnostics for the temperature measurements exist, such as the ECE radiometer but, for the plasma density, the existing diagnostics such as Lithium Beam and Thomson Scattering do not have the required high temporal resolution for a period long enough to characterize the entire ELM event. The microwave reflectometry system on ASDEX Upgrade has the capability to measure electron density profiles simultaneously at the low-field and high-field sides, in broadband swept ultrafast (35μs) operation with a spatial resolution of 5mm. In this paper we report on recent results on the effects of type I ELMs on density profiles and on the density pedestal width and ELM affected depth. During the ELM event, three phases are identified: precursor, collapse and recovery. The density pedestal width is found to be approximately constant for all the ELMy H-mode discharges analyzed here, except for high input power discharges, where an increase of the density pedestal width is observed. Major disruptions limit the range of parameters used in the operation of a tokamak, especially density limit disruptions, that limit the maximum usable density. Very abrupt increases of density are observed before the onset of the electron temperature profile erosion, supporting the hypothesis that this erosion is due to convection of the magnetic field. In ITER, during the long steady state flat-top phase of the discharges magnetic measurements may accumulate significant drifts. Plasma position and shape control using reflectometry is being assessed in ASDEX Upgrade for ITER like scenarios with successful results, where it is shown that position measurements from reflectometry compared to magnetic data satisfy the ITER requirements

  11. Measurements of electron density profiles using an angular filter refractometer

    Energy Technology Data Exchange (ETDEWEB)

    Haberberger, D., E-mail: dhab@lle.rochester.edu; Ivancic, S.; Hu, S. X.; Boni, R.; Barczys, M.; Craxton, R. S.; Froula, D. H. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636 (United States)

    2014-05-15

    A novel diagnostic technique, angular filter refractometry (AFR), has been developed to characterize high-density, long-scale-length plasmas relevant to high-energy-density physics experiments. AFR measures plasma densities up to 10{sup 21} cm{sup −3} with a 263-nm probe laser and is used to study the plasma expansion from CH foil and spherical targets that are irradiated with ∼9 kJ of ultraviolet (351-nm) laser energy in a 2-ns pulse. The data elucidate the temporal evolution of the plasma profile for the CH planar targets and the dependence of the plasma profile on target radius for CH spheres.

  12. Measurements of electron density profiles using an angular filter refractometer

    International Nuclear Information System (INIS)

    Haberberger, D.; Ivancic, S.; Hu, S. X.; Boni, R.; Barczys, M.; Craxton, R. S.; Froula, D. H.

    2014-01-01

    A novel diagnostic technique, angular filter refractometry (AFR), has been developed to characterize high-density, long-scale-length plasmas relevant to high-energy-density physics experiments. AFR measures plasma densities up to 10 21  cm −3 with a 263-nm probe laser and is used to study the plasma expansion from CH foil and spherical targets that are irradiated with ∼9 kJ of ultraviolet (351-nm) laser energy in a 2-ns pulse. The data elucidate the temporal evolution of the plasma profile for the CH planar targets and the dependence of the plasma profile on target radius for CH spheres

  13. Density profiles of supernova matter and determination of neutrino parameters

    Science.gov (United States)

    Chiu, Shao-Hsuan

    2007-08-01

    The flavor conversion of supernova neutrinos can lead to observable signatures related to the unknown neutrino parameters. As one of the determinants in dictating the efficiency of resonant flavor conversion, the local density profile near the Mikheyev-Smirnov-Wolfenstein (MSW) resonance in a supernova environment is, however, not so well understood. In this analysis, variable power-law functions are adopted to represent the independent local density profiles near the locations of resonance. It is shown that the uncertain matter density profile in a supernova, the possible neutrino mass hierarchies, and the undetermined 1-3 mixing angle would result in six distinct scenarios in terms of the survival probabilities of νe and ν¯e. The feasibility of probing the undetermined neutrino mass hierarchy and the 1-3 mixing angle with the supernova neutrinos is then examined using several proposed experimental observables. Given the incomplete knowledge of the supernova matter profile, the analysis is further expanded to incorporate the Earth matter effect. The possible impact due to the choice of models, which differ in the average energy and in the luminosity of neutrinos, is also addressed in the analysis.

  14. Earth-mass haloes and the emergence of NFW density profiles

    Science.gov (United States)

    Angulo, Raul E.; Hahn, Oliver; Ludlow, Aaron D.; Bonoli, Silvia

    2017-11-01

    We simulate neutralino dark matter (χDM) haloes from their initial collapse, at ˜ earth mass, up to a few percent solar. Our results confirm that the density profiles of the first haloes are described by a ˜r-1.5 power law. As haloes grow in mass, their density profiles evolve significantly. In the central regions, they become shallower and reach on average ˜r-1, the asymptotic form of an NFW profile. Using non-cosmological controlled simulations, we observe that temporal variations in the gravitational potential caused by major mergers lead to a shallowing of the inner profile. This transformation is more significant for shallower initial profiles and for a higher number of merging systems. Depending on the merger details, the resulting profiles can be shallower or steeper than NFW in their inner regions. Interestingly, mergers have a much weaker effect when the profile is given by a broken power law with an inner slope of -1 (such as NFW or Hernquist profiles). This offers an explanation for the emergence of NFW-like profiles: after their initial collapse, r-1.5 χDM haloes suffer copious major mergers, which progressively shallows the profile. Once an NFW-like profile is established, subsequent merging does not change the profile anymore. This suggests that halo profiles are not universal but rather a combination of (1) the physics of the formation of the microhaloes and (2) their early merger history - both set by the properties of the dark matter particle - as well as (3) the resilience of NFW-like profiles to perturbations.

  15. CO{sub 2} laser diagnostics for measurements of the plasma density profile and plasma density fluctuations on LHD

    Energy Technology Data Exchange (ETDEWEB)

    Vyacheslavov, L.N. [Budker Institute of Nuclear Physics, Novosibirsk (Russian Federation); Tanaka, K.; Kawahata, K. [National Inst. for Fusion Science, Toki, Gifu (Japan)

    2001-04-01

    A CO{sub 2} laser based diagnostics complimentary to the existing FIR interferometer is proposed. It combines interferometry for plasma density profile measurement under conditions of large density gradients, and both imaging and scattering techniques for observation of plasma fluctuations. Two-colour interferometer with a slablike probe beam and a single multichannel linear detector array provide observation of plasma density profile and density fluctuations at two locations along the probe beam. Basic characteristics of the diagnostics are considered as well as some effects that include dispersion and are critical for two colour imaging technique. The results of the bench-top experiments with the prototype of the interferometer are presented. (author)

  16. Synthesis of the diazonium (perfluoroalkyl) benzenesulfonimide monomer from Nafion monomer for proton exchange membrane fuel cells

    Science.gov (United States)

    Mei, Hua; D'Andrea, Dan; Nguyen, Tuyet-Trinh; Nworie, Chima

    2014-02-01

    One diazonium (perfluoroalkyl) benzenesulfonimide monomer, perfluoro-3, 6-dioxa-4-methyl-7-octene benzenesulfonyl imide, has been synthesized from Nafion monomer for the first time. With trifluorovinyl ether and diazonium precursors, the partially-fluorinated diazonium PFSI monomer can be polymerized and will provide chemically bonding with carbon electrode in proton exchange membrane fuel cells. A systematic study of the synthesis and characterization of this diazonium PFSI monomer has been conducted by varying reaction conditions. The optimized synthesis method has been established in the lab.

  17. Semi-analytical model of laser resonance absorption in plasmas with a parabolic density profile

    International Nuclear Information System (INIS)

    Pestehe, S J; Mohammadnejad, M

    2010-01-01

    Analytical expressions for mode conversion and resonance absorption of electromagnetic waves in inhomogeneous, unmagnetized plasmas are required for laboratory and simulation studies. Although most of the analyses of this problem have concentrated on the linear plasma density profile, there are a few research works that deal with different plasma density profiles including the parabolic profile. Almost none of them could give clear analytical formulae for the electric and magnetic components of the electromagnetic field propagating through inhomogeneous plasmas. In this paper, we have considered the resonant absorption of laser light near the critical density of plasmas with parabolic electron density profiles followed by a uniform over-dense region and have obtained expressions for the electric and magnetic vectors of laser light propagating through the plasma. An estimation of the fractional absorption of laser energy has also been carried out. It has been shown that, in contrast to the linear density profile, the energy absorption depends explicitly on the value of collision frequency as well as on a new parameter, N, called the over-dense density order.

  18. Comparison of neutral density profiles measured using Dα and C5+ in NSTX-U

    Science.gov (United States)

    Bell, R. E.; Scotti, F.; Diallo, A.; Leblanc, B. P.; Podesta, M.; Sabbagh, S. A.

    2017-10-01

    Edge neutral density profiles determined from two different measurements are compared on NSTX-U plasmas. Neutral density measurements were not typical on NSTX plasmas. An array of fibers dedicated to the measurement of passive emission of C5+, used to subtract background emission for charge exchange recombination spectroscopy (CHERS), can be used to infer deuterium neutral density near the plasma edge. The line emission from C5+ is dominated by charge exchange with neutral deuterium near the plasma edge. An edge neutral density diagnostic consisting of a camera with a Dα filter was installed on NSTX-U. The line-integrated measurements from both diagnostics are inverted to obtain local emissivity profiles. Neutral density is then inferred using atomics rates from ADAS and profile measurements from Thomson scattering and CHERS. Comparing neutral density profiles from the two diagnostic measurements helps determine the utility of using the more routinely available C5+ measurements for neutral density profiles. Initial comparisons show good agreement between the two measurements inside the separatrix. Supported by US DoE Contracts DE-AC02-09CH11466 and DE-AC52-07NA27344.

  19. Measurement of the lunar neutron density profile

    International Nuclear Information System (INIS)

    Woolum, D.S.; Burnett, D.S.; Furst, M.; Weiss, J.R.

    1975-01-01

    An in situ measurement of the lunar neutron density from 20 to 400 g cm -2 depth below the lunar surface was made by the Apollo 17 Lunar Neutron Probe Experiment (LNPE) using particle tracks produced by the 10 B (n,α) 7 Li reaction. Both the absolute magnitude and the depth profile of the neutron density are in good agreement with theoretical calculations by Lingenfelter, Canfield, and Hampel. However, relatively small deviations between experiment and theory in the effect of Cd absorption on the neutron density and in the relative 149 Sm to 157 Gd capture rates reported previously (Russ et al., 1972) imply that the true lunar 157 Gd capture rate is about one half of that calculated theoretically. (Auth.)

  20. A Numerical Fit of Analytical to Simulated Density Profiles in Dark Matter Haloes

    Science.gov (United States)

    Caimmi, R.; Marmo, C.; Valentinuzzi, T.

    2005-06-01

    Analytical and geometrical properties of generalized power-law (GPL) density profiles are investigated in detail. In particular, a one-to-one correspondence is found between mathematical parameters (a scaling radius, r_0, a scaling density, rho_0, and three exponents, alpha, beta, gamma), and geometrical parameters (the coordinates of the intersection of the asymptotes, x_C, y_C, and three vertical intercepts, b, b_beta, b_gamma, related to the curve and the asymptotes, respectively): (r_0,rho_0,alpha,beta,gamma) (x_C,y_C,b,b_beta,b_gamma). Then GPL density profiles are compared with simulated dark haloes (SDH) density profiles, and nonlinear least-absolute values and least-squares fits involving the above mentioned five parameters (RFSM5 method) are prescribed. More specifically, the sum of absolute values or squares of absolute logarithmic residuals, R_i= log rhoSDH(r_i)-log rhoGPL(r_i), is evaluated on 10^5 points making a 5- dimension hypergrid, through a few iterations. The size is progressively reduced around a fiducial minimum, and superpositions on nodes of earlier hypergrids are avoided. An application is made to a sample of 17 SDHs on the scale of cluster of galaxies, within a flat LambdaCDM cosmological model (Rasia et al. 2004). In dealing with the mean SDH density profile, a virial radius, rvir, averaged over the whole sample, is assigned, which allows the calculation of the remaining parameters. Using a RFSM5 method provides a better fit with respect to other methods. The geometrical parameters, averaged over the whole sample of best fitting GPL density profiles, yield (alpha,beta,gamma) approx(0.6,3.1,1.0), to be compared with (alpha,beta,gamma)=(1,3,1), i.e. the NFW density profile (Navarro et al. 1995, 1996, 1997), (alpha,beta,gamma)=(1.5,3,1.5) (Moore et al. 1998, 1999), (alpha,beta,gamma)=(1,2.5,1) (Rasia et al. 2004); and, in addition, gamma approx 1.5 (Hiotelis 2003), deduced from the application of a RFSM5 method, but using a different

  1. Characterization of laser-produced plasma density profiles using grid image refractometry

    International Nuclear Information System (INIS)

    Craxton, R.S.; Turner, F.S.; Hoefen, R.; Darrow, C.; Gabl, E.F.; Busch, G.E.

    1993-01-01

    Grid image refractometry (GIR) is proposed as a technique for determining the two-dimensional density profiles of long scale-length laser-produced plasmas. Its distinctive feature is that an optical probe beam is broken up into ''rays'' by being passed through a grid before traversing the plasma. The refraction angles of the rays are measured by imaging the plasma at two or more object planes and are integrated to yield the phase front. For cylindrically symmetric plasmas the density profile is then determined using Abel inversion. The feasibility of GIR is illustrated by an experiment in which a thick CH target was irradiated with ∼100 J of 527 nm radiation and diagnosed with a 20 ps, 263 nm probe. The resulting density profile is substantially larger than any that have previously been reported using interferometry and compares quite closely with hydrodynamic simulations

  2. Exploration of one-dimensional plasma current density profile for K-DEMO steady-state operation

    Energy Technology Data Exchange (ETDEWEB)

    Kang, J.S. [Seoul National University, Seoul 151-742 (Korea, Republic of); Jung, L. [National Fusion Research Institute, Daejeon (Korea, Republic of); Byun, C.-S.; Na, D.H.; Na, Y.-S. [Seoul National University, Seoul 151-742 (Korea, Republic of); Hwang, Y.S., E-mail: yhwang@snu.ac.kr [Seoul National University, Seoul 151-742 (Korea, Republic of)

    2016-11-01

    Highlights: • One-dimensional current density and its optimization for the K-DEMO are explored. • Plasma current density profile is calculated with an integrated simulation code. • The impact of self and external heating profiles is considered self-consistently. • Current density is identified as a reference profile by minimizing heating power. - Abstract: Concept study for Korean demonstration fusion reactor (K-DEMO) is in progress, and basic design parameters are proposed by targeting high magnetic field operation with ITER-sized machine. High magnetic field operation is a favorable approach to enlarge relative plasma performance without increasing normalized beta or plasma current. Exploration of one-dimensional current density profile and its optimization process for the K-DEMO steady-state operation are reported in this paper. Numerical analysis is conducted with an integrated plasma simulation code package incorporating a transport code with equilibrium and current drive modules. Operation regimes are addressed with zero-dimensional system analysis. One-dimensional plasma current density profile is calculated based on equilibrium, bootstrap current analysis, and thermal transport analysis. The impact of self and external heating profiles on those parameters is considered self-consistently, where thermal power balance and 100% non-inductive current drive are the main constraints during the whole exploration procedure. Current and pressure profiles are identified as a reference steady-state profile by minimizing the external heating power with desired fusion power.

  3. Response of temperature and density profiles to heat deposition profile and its impact on global scaling in LHD

    International Nuclear Information System (INIS)

    Yamada, H.; Murakami, S.; Yamazaki, K.

    2002-01-01

    Energy confinement and heat transport of net current-free NBI-heated plasmas in the Large Helical Device (LHD) are discussed with an emphasis on density dependence. Although the apparent density dependence of the energy confinement time has been demonstrated in a wide parameter range in LHD, the loss of this dependence has been observed in the high density regime under the specific condition. Broad heat deposition due to off-axis alignment and shallow penetration of neutral beams degrades the global energy confinement while the local heat transport maintains a clear temperature dependence lying between Bohm and gyro-Bohm characteristics. The central heat deposition inclines towards an intrinsic density dependence like τ E ∝(n-bar e /P) 0.6 from the saturated state. The broadening of the temperature profile due to the broad heat deposition profile contrasts with the invariant property which has observed widely as profile consistency and stiffness in tokamak experiments. (author)

  4. Response of temperature and density profiles to heat deposition profile and its impact on global scaling in LHD

    International Nuclear Information System (INIS)

    Yamada, H.; Murakami, S.; Yamazaki, K.

    2003-01-01

    Energy confinement and heat transport of net current-free NBI-heated plasmas in the Large Helical Device (LHD) are discussed with an emphasis on density dependence. Although the apparent density dependence of the energy confinement time has been demonstrated in a wide parameter range in LHD, the loss of this dependence has been observed in the high density regime under the specific condition. Broad heat deposition due to off-axis alignment and shallow penetration of neutral beams degrades the global energy confinement while the local heat transport maintains a clear temperature dependence lying between Bohm and gyro-Bohm characteristics. The central heat deposition inclines towards an intrinsic density dependence like τ E ∝(n-bars e /P) 0.6 from the saturated state. The broadening of the temperature profile due to the broad heat deposition profile contrasts with the invariant property which has observed widely as profile consistency and stiffness in tokamak experiments. (author)

  5. Exact analytical density profiles and surface tension

    Indian Academy of Sciences (India)

    journal of. May 2005 physics pp. 785–801. Classical charged fluids at equilibrium near ... is provided by the excess surface tension for an air–water interface, which is determined ... the potential drop created by the electric layer which appears as soon as the fluid has ...... radii, by symmetry, the charge density profile is flat,.

  6. Copolymerization of Carbon–carbon Double-bond Monomer (Styrene with Cyclic Monomer (Tetrahydrofuran

    Directory of Open Access Journals (Sweden)

    Sari Fouad

    2012-12-01

    Full Text Available We reported in this work that the cationic copolymerization in one step takes place between carbon–carbon double-bond monomer styrene with cyclic monomer tetrahydrofuran. The comonomers studied belong to different families: vinylic and cyclic ether. The reaction is initiated with maghnite-H+ an acid exchanged montmorillonite as acid solid ecocatalyst. Maghnite-H+ is already used as catalyst for polymerization of many vinylic and heterocyclic monomers. The oxonium ion of tetrahydrofuran and carbonium ion of styrene propagated the reaction of copolymerization. The acetic anhydride is essential for the maintenance of the ring opening of tetrahydrofuran and the entry in copolymerization. The temperature was kept constant at 40°C in oil bath heating for 6 hours. A typical reaction product was analyzed by 1H-NMR, 13C-NMR and IR and the formation of the copolymer was confirmed. The reaction was proved by matched with analysis. The maghnite-H+ allowed us to obtain extremely pure copolymer in good yield by following a simples operational conditions. Copyright © 2012 by BCREC UNDIP. All rights reservedReceived: 29th October 2012; Revised: 29th November 2012; Accepted: 29th November 2012[How to Cite: S. Fouad, M.I. Ferrahi, M. Belbachir. (2012. Copolymerization of Carbon–carbon Double-bond Monomer (Styrene with Cyclic Monomer (Tetrahydrofuran. Bulletin of Chemical Reaction Engineering & Catalysis, 7(2: 165-171. (doi:10.9767/bcrec.7.2.4074.165-171][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.4074.165-171 ] | View in 

  7. Equatorial bottom and topside electron density profiles and comparison with IRI

    International Nuclear Information System (INIS)

    Reinisch, B.W.; Huang, X.; Conway, J.; Komjathy, A.

    2001-01-01

    A new technique of estimating the ionospheric topside profile from the information contained in the groundbased ionograms is described. The electron density profile above the F2 layer peak is approximated by an α-Chapman function with a constant scale height that is derived from the bottomside profile shape near the F2 peak. The scale height is obtained from the bottomside profile by representing the latter in terms of α-Chapman functions with scale heights H(h) that vary as a function of height. The scale height at the layer peak is then used for the topside profile. The bottomside and topside electron contents is obtained by integrating the electron density from h=0 to hmF2 and from hmF2 to ∞. The ionogram derived electron content values for Jicamarca in 1998 are compared with the respective IRI values. (author)

  8. Jellium-model calculation for monomer and dimer decays of some potassium clusters

    International Nuclear Information System (INIS)

    Saito, Susumu; Cohen, M.L.; Lawrence Berkeley Lab., CA

    1989-01-01

    We have studied several decay processes of potassium clusters and found that a dimer-decay mechanism can explain the observed lowest abundance of K 10 in the K n mass spectra. Total-energy curves for decay processes are calculated using a jellium-background model for positive-ion cores and the local-spin-density-functional approximation for valence electrons. The energy-barrier height for a dimer decay of K 10 from the energy-minimum point is found to be 0.18 eV, which is a reasonable magnitude for the decay to take place thermally in the experiment. The monomer decay of K 9 and the dimer decay of K 11 , which are expected to be the most favorable decays of K 9 and K 11 , are found to have high barriers. Monomer and dimer decays of K 8 are also studied and the monomer decay is found to be more favorable, in accord with the high-nozzle-temperature mass spectrum. (orig.)

  9. ICRF power-deposition profiles and heating in monster sawtooth and peaked-density profile discharges in JET

    International Nuclear Information System (INIS)

    Bhatnagar, V.P.; Taroni, A.; Ellis, J.J.; Jacquinot, J.; Stuart, D.F.

    1989-01-01

    In this paper, we compare experimental results of electron and ion-heating in discharges that feature monster sawtooth with those in pellet-produced peaked-density profile discharges which were heated with ICRF. Also we carry out a comprehensive analysis of ICRF-heated peaked-density profile discharges by a transport code to simulate the evolution of JET discharges and to provide an insight into the improved heating and confinement found in these discharges. In this analysis, the ICRF power-deposition profile in the minority-heating scenario is computed by the ray-tracing code BRAYCO that self-consistently takes the finite antenna geometry, its radiation spectrum and the hot-plasma damping into account. The power delivered to ions and electrons is calculated based on Stix model. (author) 10 refs., 5 figs

  10. Confinement properties of JET plasmas with different temperature and density profiles

    International Nuclear Information System (INIS)

    Watkins, M.L.; Balet, B.; Bhatnagar, V.P.

    1989-01-01

    The confinement properties of plasmas with substantially different temperature and density profiles have been analysed. The effects of fast particles and energy pedestals on the overall confinement of plasma energy in limiter (L-mode) and X-point (L- and H-modes) discharges heated by NBI or ICRF or both are determined. The importance of the bootstrap current when such energy pedestals are formed is noted. Using sets of consistent experimental data, including ion temperature profile measurements, the local transport properties are compared in the L- and H-phases of a single null X-point medium density NBI heated discharge, the ''enhanced'' confinement phase of a limiter high density pellet-fuelled and ICRF heated discharge, the hot-ion phase of a double null X-point low density NBI heated discharge and the hot-ion and H-phases of a double null X-point low density high temperature NBI heated discharge. (author)

  11. The role of monomer fraction data in association theories—Can we improve the performance for phase equilibrium calculations?

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Bøgh, David; Karakatsani, Eirini

    2014-01-01

    with different ethanol content as inhibitor. There are some differences in the performance of CPA with the two sets but on average the results are similar. This may indicate that monomer fraction data are not very useful in this case or that ethanol monomer fraction data are not accurate and both possibilities...... accurate and how useful are such data today and how successful is their use in the context of association models? In this work we attempt to answer these questions in the case of the CPA model and for ethanol. CPA has been already successfully used to describe thermodynamic properties of many ethanol...... containing mixtures, using an ethanol parameter set that was adjusted to experimental vapor pressure and liquid density data. We present in this work a new parameter set for ethanol which is estimated using experimental vapor pressure, liquid density data as well as the experimental monomer fractions...

  12. Measurement of electron density profiles by soft X-ray tomography on the RTP tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, D.F. da; Donne, A.J.H.; Lyadina, E.S.; Rutteman, R.H.; Tanzi, C.P. [FOM-Instituut voor Plasmafysica, Rijnhuizen (Netherlands)

    1993-12-31

    Tomographic diagnosis of the soft x-ray emissivity profile is a powerful method for studying several plasma parameters. The x-ray emissivity is a complicated function of plasma quantities like the electron density and temperature, and the impurity content in the plasma. These quantities can be studied separately provided that information is available on the remaining parameters. Soft x-ray emissivity profiles have already been used successfully in other machines to determine local values of impurity densities and the effective charge Z{sub eff}. In the RTP tokamak the electron density profile has been inferred from a modelling of the x-ray emissivity in situations where information is available on the electron temperature profile, the value of Z{sub eff}, and the relative proportion of the impurities. The method can be useful for the study of hollow density profiles that cannot be properly reconstructed by Abel inversion of interferometer or reflectometer data. (author) 7 refs., 2 figs.

  13. Measurement of electron density profiles by soft X-ray tomography on the RTP tokamak

    International Nuclear Information System (INIS)

    Cruz, D.F. da; Donne, A.J.H.; Lyadina, E.S.; Rutteman, R.H.; Tanzi, C.P.

    1993-01-01

    Tomographic diagnosis of the soft x-ray emissivity profile is a powerful method for studying several plasma parameters. The x-ray emissivity is a complicated function of plasma quantities like the electron density and temperature, and the impurity content in the plasma. These quantities can be studied separately provided that information is available on the remaining parameters. Soft x-ray emissivity profiles have already been used successfully in other machines to determine local values of impurity densities and the effective charge Z eff . In the RTP tokamak the electron density profile has been inferred from a modelling of the x-ray emissivity in situations where information is available on the electron temperature profile, the value of Z eff , and the relative proportion of the impurities. The method can be useful for the study of hollow density profiles that cannot be properly reconstructed by Abel inversion of interferometer or reflectometer data. (author) 7 refs., 2 figs

  14. Thermodynamics of monomer partitioning in polymer latices: effect of molar volume of the monomers

    NARCIS (Netherlands)

    Schoonbrood, H.A.S.; German, A.L.

    1994-01-01

    A model of the thermodn. of partitioning of moderately water-sol. monomers in polymer latex systems is developed to show deviations that occur when the molar vols. of the monomers are not similar. The model, as well as expts. with Me acrylate and cyclohexyl methacrylate in polystyrene latex systems,

  15. Environmental effects on the lignin model monomer, vanillyl alcohol, studied by raman spectroscopy

    DEFF Research Database (Denmark)

    Larsen, Kiki Lyster; Barsberg, Søren Talbro

    2011-01-01

    model monomer, vanillyl alcohol (G type), dissolved in different solvents were compared to investigate such effects on the Raman band shapes and positions. Density functional theory combined with the polarizable continuum model were applied to assign the observed bands and tested for prediction accuracy...

  16. Dark matter and gas density profiles - a consequence of entropy bifurcation

    International Nuclear Information System (INIS)

    Leubner, M. P.

    2006-01-01

    The radial profiles of dark matter and hot plasma density distributions of relaxed galaxies and clusters were hitherto commonly fitted by empirical functions. On the other hand, the fundamental concept of non-extensive statistics accounts for long-range interactions and correlations present in gravitationally coupled ensembles and plasmas. We provide a theoretical link of non-extensive statistics to large scale astrophysical structures and show that the underlying tandem character of the entropy results in a bifurcation of the density distribution. A kinetic dark matter and thermodynamic gas branch turn out as natural consequence within the theory and is controlled by one single parameter, measuring physically the degree of correlations in the system. The theoretically derived density profiles are shown to represent accurately the characteristics of both, DM and hot plasma distributions, as observed or generated in N-body and hydro-simulations. The significant advantage over empirical fitting functions is provided by the physical content of the non-extensive approach wherefore it is proposed to model observed density profiles of astrophysical structures within the fundamental context of entropy generalization, accounting for nonlocality and long-range interactions in gravitationally coupled systems

  17. Increase of the density of commercial graphite

    International Nuclear Information System (INIS)

    Tobias, H.; Meyerstein, D.

    1977-12-01

    The increase of the density of commercial graphite of the type ATJ by polymerization of an impregnated monomer, followed by pyrolysis, is described. The monomer which was either styrene or acrylonitrile, was irradiated by a 60 Co source and pyrolized in a standard vacuum system. The irradiation dose for the polymerization of the monomer was determined. Suggestions for the establishment of the optimum conditions are offered

  18. Electron temperature and density profiles measurement in the TJ-1 tokamak by Thomson scattering

    International Nuclear Information System (INIS)

    Pardo, C.; Zurro, B.

    1986-01-01

    Electron temperature and density profiles of ohmically heated hydrogen plasmas in the TJ-1 tokamak have been measured by Thomson scattering. The temperature profile peaks sharply in the central region while the density profile is very flat. Temperature values between 100 and 390 eV have been measured for densities in the range of 5.10 12 to 2.6.10 13 cm -3 . Parameters characterizing TJ-1 plasma, such as confinement times Z eff , have been deduced from experimental data. Energy confinement times are compared with experimental scaling laws. (author)

  19. A density functional theory study on the conversion of ethylene to carbon monomer on PdAu(1 0 0) surface

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Minhua; Yang, Bing [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin 300072 (China); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072 (China); Yu, Yingzhe, E-mail: yzhyu@tju.edu.cn [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin 300072 (China); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072 (China)

    2015-11-30

    Graphical abstract: - Highlights: • The successive decomposition of ethylene on PdAu(1 0 0) was studied with DFT method. • The C−H, C−C bond scission and a hydrogen-shift process were investigated. • The alloying of Au with Pd affects the studied reactions on PdAu(1 0 0) greatly. - Abstract: Calculations based on the first-principles density functional theory (DFT) were performed to study the possible transformation pathways of ethylene on PdAu(1 0 0) surface to investigate the effect of Au atom alloying with Pd on the formation of CHx (x = 0–2), which may eventually form carbon monomer and lead to the deactivation of catalysts. The energetic properties of reactions including the scission of the C−H, C−C bond and a hydrogen-shift process were determined. The C−H bond scission is confirmed to be prone to happen on the studied surface, while it is difficult for the C−C bond scission to occur due to relatively high barriers, the values of which are as high as 2.72–4.62 eV. The activation barriers for all related reactions except for the dehydrogenation of vinyl, vinylidene and acetenyl demonstrate that it is harder for the conversion of ethylene to occur on PdAu(1 0 0) surface than on Pd(1 0 0) surface, especially for the C−C bond scission. All the results indicate that the alloying of Au atom with pure Pd catalyst can prevent the formation of carbon monomer, which may notably affect properties of catalysts.

  20. Dwarf galaxy dark matter density profiles inferred from stellar and gas kinematics

    International Nuclear Information System (INIS)

    Adams, Joshua J.; Simon, Joshua D.; Fabricius, Maximilian H.; Bender, Ralf; Thomas, Jens; Van den Bosch, Remco C. E.; Van de Ven, Glenn; Barentine, John C.; Gebhardt, Karl; Hill, Gary J.; Murphy, Jeremy D.; Swaters, R. A.

    2014-01-01

    We present new constraints on the density profiles of dark matter (DM) halos in seven nearby dwarf galaxies from measurements of their integrated stellar light and gas kinematics. The gas kinematics of low-mass galaxies frequently suggest that they contain constant density DM cores, while N-body simulations instead predict a cuspy profile. We present a data set of high-resolution integral-field spectroscopy on seven galaxies and measure the stellar and gas kinematics simultaneously. Using Jeans modeling on our full sample, we examine whether gas kinematics in general produce shallower density profiles than are derived from the stars. Although two of the seven galaxies show some localized differences in their rotation curves between the two tracers, estimates of the central logarithmic slope of the DM density profile, γ, are generally robust. The mean and standard deviation of the logarithmic slope for the population are γ = 0.67 ± 0.10 when measured in the stars and γ = 0.58 ± 0.24 when measured in the gas. We also find that the halos are not under-concentrated at the radii of half their maximum velocities. Finally, we search for correlations of the DM density profile with stellar velocity anisotropy and other baryonic properties. Two popular mechanisms to explain cored DM halos are an exotic DM component or feedback models that strongly couple the energy of supernovae into repeatedly driving out gas and dynamically heating the DM halos. While such models do not yet have falsifiable predictions that we can measure, we investigate correlations that may eventually be used to test models. We do not find a secondary parameter that strongly correlates with the central DM density slope, but we do find some weak correlations. The central DM density slope weakly correlates with the abundance of α elements in the stellar population, anti-correlates with H I fraction, and anti-correlates with vertical orbital anisotropy. We expect, if anything, the opposite of these

  1. THE DARK MATTER DENSITY PROFILE OF THE FORNAX DWARF

    International Nuclear Information System (INIS)

    Jardel, John R.; Gebhardt, Karl

    2012-01-01

    We construct axisymmetric Schwarzschild models to measure the mass profile of the Local Group dwarf galaxy Fornax. These models require no assumptions to be made about the orbital anisotropy of the stars, as is the case for commonly used Jeans models. We test a variety of parameterizations of dark matter density profiles and find cored models with uniform density ρ c = (1.6 ± 0.1) × 10 –2 M ☉ pc –3 fit significantly better than the cuspy halos predicted by cold dark matter simulations. We also construct models with an intermediate-mass black hole, but are unable to make a detection. We place a 1σ upper limit on the mass of a potential intermediate-mass black hole at M . ≤ 3.2 × 10 4 M ☉ .

  2. Diagnostic development for current density profile control at KSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Ko, J., E-mail: jinseok@nfri.re.kr [National Fusion Research Institute, Daejeon 34133 (Korea, Republic of); University of Science and Technology, Daejeon 34113 (Korea, Republic of); Chung, J. [National Fusion Research Institute, Daejeon 34133 (Korea, Republic of); Messmer, M.C.C. [Department of Applied Physics, Eindhoven University of Technology, Eindhoven (Netherlands)

    2016-11-01

    Highlights: • The motional Stark effect (MSE) diagnostic installed at KSTAR. • Engineering challenges and solutions on the design and fabrication of the front optics housing and filter modules. • Characterization of the bandpass filters and the responses to polarized light. - Abstract: The current density profile diagnostics are critical for the control of the steady-state burning plasma operations. A multi-channel motional Stark effect (MSE) diagnostic system has been implemented for the measurements of the internal magnetic field structures that constrain the magnetic equilibrium reconstruction to accurately produce the tokamak safety factor and current density profiles for the Korea Superconducting Tokamak Advanced Research (KSTAR). This work presents the design and fabrication of the front optics and the filter modules and the calibration activities for the MSE diagnostic at KSTAR.

  3. Monomer-dependent secondary nucleation in amyloid formation.

    Science.gov (United States)

    Linse, Sara

    2017-08-01

    Secondary nucleation of monomers on the surface of an already existing aggregate that is formed from the same kind of monomers may lead to autocatalytic amplification of a self-assembly process. Such monomer-dependent secondary nucleation occurs during the crystallization of small molecules or proteins and self-assembled materials, as well as in protein self-assembly into fibrous structures. Indications of secondary nucleation may come from analyses of kinetic experiments starting from pure monomers or monomers supplemented with a low concentration of pre-formed aggregates (seeds). More firm evidence requires additional experiments, for example those employing isotope labels to distinguish new aggregates arising from the monomer from those resulting from fragmentation of the seed. In cases of amyloid formation, secondary nucleation leads to the formation of toxic oligomers, and inhibitors of secondary nucleation may serve as starting points for therapeutic developments. Secondary nucleation displays a high degree of structural specificity and may be enhanced by mutations or screening of electrostatic repulsion.

  4. Edge density profile measurements by X-mode reflectometry on Tore Supra

    International Nuclear Information System (INIS)

    Clairet, F.; Bottereau, C.; Chareau, J.M.; Paume, M.; Sabot, R.

    2000-10-01

    A broadband reflectometer operating in the frequency range 50-75 GHz has been developed on Tore Supra to measure electron density profiles at the edge. The system uses extraordinary mode polarization and performs routine measurements in 20 μs with a heterodyne detection to ensure a high dynamic range sensitivity. It allows separate phase and amplitude information of the signal. The density profiles are fully automatically calculated from the raw phase. The initialization is done with an automatic detection of the first cut-off from the amplitude of the reflected signal with accuracy up to ±0.5 cm. The profiles are now part of the public database of Tore Supra (TS) and can provide details of density structures better than the centimeter range. High reliability of the measurements for various plasma conditions make this diagnostic an ideal tool to study specific edge plasma physics with given examples on detached plasma behaviour and RF antenna-plasma coupling processes. It also is shown how the presence of suprathermal electrons may perturb the measurements. (authors)

  5. High precision measurement of fuel density profiles in nuclear fusion plasmas

    NARCIS (Netherlands)

    Svensson, J.; von Hellermann, M.; Konig, R.

    2002-01-01

    This paper presents a method for deducing fuel density profiles of nuclear fusion plasmas in realtime during an experiment. A Multi Layer Perceptron (MLP) neural network is used to create a mapping between plasma radiation spectra and indirectly deduced hydrogen isotope densities. By combining

  6. Non-power law behavior of the radial profile of phase-space density of halos

    International Nuclear Information System (INIS)

    Popolo, A. Del

    2011-01-01

    We study the pseudo phase-space density, ρ(r)/σ 3 (r), of ΛCDM dark matter halos with and without baryons (baryons+DM, and pure DM), by using the model introduced in Del Popolo (2009), which takes into account the effect of dynamical friction, ordered and random angular momentum, baryons adiabatic contraction and dark matter baryons interplay. We examine the radial dependence of ρ(r)/σ 3 (r) over 9 orders of magnitude in radius for structures on galactic and cluster of galaxies scales. We find that ρ(r)/σ 3 (r) is approximately a power-law only in the range of halo radius resolved by current simulations (down to 0.1% of the virial radius) while it has a non-power law behavior below the quoted scale, with inner profiles changing with mass. The non-power-law behavior is more evident for halos constituted both of dark matter and baryons while halos constituted just of dark matter and with angular momentum chosen to reproduce a Navarro-Frenk-White (NFW) density profile, are characterized by an approximately power-law behavior. The results of the present paper lead to conclude that density profiles of the NFW type are compatible with a power-law behavior of ρ(r)/σ 3 (r), while those flattening to the halo center, like those found in Del Popolo (2009) or the Einasto profile, or the Burkert profile, cannot produce radial profile of the pseudo-phase-space density that are power-laws at all radii. The results argue against universality of the pseudo phase-space density and as a consequence argue against universality of density profiles constituted by dark matter and baryons as also discussed in Del Popolo (2009)

  7. Electron density profile determination by means of laser blow-off injected neutral beam

    International Nuclear Information System (INIS)

    Kocsis, G.; Bakos, J.S.; Ignacz, P.N.; Kardon, B.; Koltai, L.; Veres, G.

    1992-01-01

    This paper is devoted to the experimental and theoretical studies of the determination of the electron density profiles by means of laser blow-off neutrals. For the determination of the density profile the time and spatial distributions of the spectral line radiation intensity of the injected neutrals are used. The method is compared to other previously proposed methods and the advantages and disadvantages of the different methods are discussed. The result of the comparison is that our method gives the most reliable result with the highest temporal resolution for the density profile of the edge plasma. The only disadvantage is the need of careful calibration of the sensitivity of the spatial channels. The advantage is the ability of the method as a standard diagnostic. (orig.)

  8. Role of substituents on the reactivity and electron density profile of ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 125; Issue 5. Role of substituents on the reactivity and electron density profile of diimine ligands: A density functional theory based study. Bhakti S Kulkarni Deepti Mishra Sourav Pal. Volume 125 Issue 5 September 2013 pp 1247-1258 ...

  9. Interaction of the modulated electron beam with inhomogeneous plasma: plasma density profile deformation and langmuir waves excitation

    International Nuclear Information System (INIS)

    Anisimov, I.O.; Kelnyk, O.I.; Soroka, S.V.; Siversky, T.V.

    2005-01-01

    Nonlinear deformation of the initially linear plasma density profile due to the modulated electron beam is studied via computer simulation. In the initial time period the field slaves to the instantaneous profile of the plasma density. Langmuir waves excitation is suppressed by the density profile deformation. The character of the plasma density profile deformation for the late time period depends significantly on the plasma properties. Particularly, for plasma with hot electrons quasi-periodic generation of ion-acoustic pulses takes place in the vicinity of the initial point of plasma resonance

  10. Preparation of supramolecular polymers by copolymerization of monomers containing quadruple hydrogen bonding units with regular monomers

    NARCIS (Netherlands)

    2004-01-01

    The invention relates to the synthesis of polymers containing self-complementary quadruple hydrogen groups by copolymerizing monomers containing a quadruple hydrogen bonding group with one or more monomers of choice. The resulting polymers show unique new characteristics due to the presence of

  11. Preparation of supramolecular polymers by copolymerization of monomers containing quadruple hydrogen bonding units with regular monomers

    NARCIS (Netherlands)

    2004-01-01

    The invention relates to the synthesis of polymers contg. self-complementary quadruple H groups by copolymg. monomers contg. a quadruple H bonding group with ³1 monomers of choice. The resulting polymers show unique new characteristics due to the presence of addnl. phys. interactions between the

  12. Electron density and temperature profile diagnostics for C-2 field reversed configuration plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Deng, B. H.; Kinley, J. S.; Schroeder, J. [Tri Alpha Energy, Inc., Rancho Santa Margarita, California 92688 (United States)

    2012-10-15

    The 9-point Thomson scattering diagnostic system for the C-2 field reversed configuration plasmas is improved and the measured electron temperature profiles are consistent with theoretical expectations. Rayleigh scattering revealed a finite line width of the ruby laser emission, which complicates density calibration. Taking advantage of the plasma wobble motion, density profile reconstruction accuracy from the 6-chord two-color CO{sub 2}/HeNe interferometer data is improved.

  13. Transport simulations of a density limit in radiation-dominated tokamak discharges: Profile effects

    International Nuclear Information System (INIS)

    Stotler, D.P.

    1988-06-01

    The density limit observed in tokamak experiments is thought to be due to a radiative collapse of the current channel. A transport code coupled with an MHD equilibrium routine is used to determine the detailed, self-consistent evolution of the plasma profiles in tokamak discharges with radiated power close to or equalling the input power. The present work is confined to ohmic discharges in steady state. It is found that the shape of the density profile can have a significant impact on the variation of the maximum electron density with plasma current. Analytic calculations confirm this result. 41 refs., 9 figs

  14. Transport simulations of a density limit in radiation-dominated tokamak discharges: profile effects

    International Nuclear Information System (INIS)

    Stotler, D.P.

    1988-01-01

    The density limit observed in tokamak experiments is thought to be due to a radiative collapse of the current channel. A transport code coupled with a magnetohydrodynamic (MHD) equilibrium routine is used to determine the detailed, self-consistent evolution of the plasma profiles in tokamak discharges with radiated power close to or equaling the input power. The present work is confined to Ohmic discharges in steady state. It is found that the shape of the density profile can have a significant impact on the variation of the maximum electron density with plasma current. Analytic calculations confirm this result

  15. Experimental electron density profiles of the mid-latitude lower ionosphere and winter anomaly

    International Nuclear Information System (INIS)

    Rapoport, Z.Ts.; Sinel'nikov, V.M.

    1996-01-01

    Summarized measurements of high-latitude electron density profiles of N e lower ionosphere, obtained at M100B meteorological rockets by precision method of coherent frequencies during 1979-1990 at the Volgograd test site (φ = 48 deg 41' N; λ = 44 deg 21 E), are presented. The profiles obtained represent average values of electron density at various altitudes of lower ionosphere (h = 70-100 km) during night and day time hours in winter and non winter periods. Increased electron density values during daytime hours in winter are related to winter anomaly phenomenon. 36 refs.; 1 fig

  16. Behavior of the bottomside electron density profile over Pruhonice

    Czech Academy of Sciences Publication Activity Database

    Mosert, M.; Burešová, Dalia; Ezquer, R.; Mansilla, G.

    2004-01-01

    Roč. 34, č. 9 (2004), s. 1982-1989 ISSN 0273-1177 R&D Projects: GA AV ČR IAA3042102 Institutional research plan: CEZ:AV0Z3042911 Keywords : Electron density profiles * Variability Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 0.548, year: 2004

  17. Interference of functional monomers with polymerization efficiency of adhesives.

    Science.gov (United States)

    Hanabusa, Masao; Yoshihara, Kumiko; Yoshida, Yasuhiro; Okihara, Takumi; Yamamoto, Takatsugu; Momoi, Yasuko; Van Meerbeek, Bart

    2016-04-01

    The degree of conversion (DC) of camphorquinone/amine-based adhesives is affected by acidic functional monomers as a result of inactivation of the amine co-initiator through an acid-base reaction. During bonding, functional monomers of self-etch adhesives chemically interact with hydroxyapatite (HAp). Here, we tested in how far the latter interaction of functional monomers with HAp counteracts the expected reduction in DC of camphorquinone/amine-based adhesives. The DC of three experimental adhesive formulations, containing either of the two functional monomers [10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) or 4-methacryloxyethyl trimellitic acid anhydride (4-META)] or no functional monomer (no-FM; control), was measured with and without HAp powder added to the adhesive formulations. Both the variables 'functional monomer' and 'HAp' were found to be significant, with the functional monomer reducing the DC and HAp counteracting this effect. It is concluded that the functional monomers 10-MDP and 4-META interfere with the polymerization efficiency of adhesives. This interference is less prominent in the presence of HAp, which would clinically correspond to when these two functional monomers of the adhesive simultaneously interact with HAp in tooth tissue. © 2016 Eur J Oral Sci.

  18. ICRF power-deposition profiles, heating and confinement of monster sawtooth and peaked-density profile discharges in JET

    International Nuclear Information System (INIS)

    Bhatnagar, V.P.; Taroni, A.; Ellis, J.J.; Jacquinot, J.; Start, D.F.H.

    1989-01-01

    The ion cyclotron resonance heating of monster sawtooth (period greater than the energy confinement time) and pellet-fueled peaked-density profiles in limiter discharges of JET Tokamak are studied. The monster sawtooth is a characteristic JET regime which is related to fast ions generated during the minority ion heating. In the ICRF heating of peaked-density profile discharges, we find typically the T i0 is higher roughly by a factor of 2 and T e0 roughly by 35% at a fixed P TOT /n e0 when compared to non-peaked profile cases. Here, T e0 and T i0 are central electron and ion temperatures, respectively, n e0 is the central electron density and P TOT is the total input power. The ion heating is improved in the pellet case, in part, due to a higher collisionality between the background ions and the energetic minority, but more significantly by a reduction of local ion energy transport in the central region. The transport-code simulation of these discharges reveals that there is a reduction of both χ e and χ i in the central region of the plasma in the ICRF heated peaked-profile discharges where χ e and χ i are the electron and ion heat conductivities, respectively. The improvement of confinement is not explained quantitatively by any of the existing η i -driven turbulence theories as the n i parameter (η i = d ln T i /d ln n i where T i is the ion temperature and n i is the ion density), instead of dropping below the critical value, remains above it for most of the duration of the improved confinement phase. The physical mechanism(s) that plays a role in this improvement is not yet clear. (author)

  19. Ionic Liquid Epoxy Resin Monomers

    Science.gov (United States)

    Paley, Mark S. (Inventor)

    2013-01-01

    Ionic liquid epoxide monomers capable of reacting with cross-linking agents to form polymers with high tensile and adhesive strengths. Ionic liquid epoxide monomers comprising at least one bis(glycidyl) N-substituted nitrogen heterocyclic cation are made from nitrogen heterocycles corresponding to the bis(glycidyl) N-substituted nitrogen heterocyclic cations by a method involving a non-nucleophilic anion, an alkali metal cation, epichlorohydrin, and a strong base.

  20. Oligonucleotides with 1,4-dioxane-based nucleotide monomers

    DEFF Research Database (Denmark)

    Madsen, Andreas S; Wengel, Jesper

    2012-01-01

    An epimeric mixture of H-phosphonates 5R and 5S has been synthesized in three steps from known secouridine 1. Separation of the epimers has been accomplished by RP-HPLC, allowing full characterization and incorporation of monomers X and Y into 9-mer oligonucleotides using H-phosphonates building...... blocks 5R and 5S, respectively. A single incorporation of either monomer X or monomer Y in the central position of a DNA 9-mer results in decreased thermal affinity toward both DNA and RNA complements (ΔT(m) = -3.5 °C/-3.5 °C for monomer X and ΔT(m) = -11.0 °C/-6.5 °C for monomer Y). CD measurements do...

  1. Surface active monomers synthesis, properties, and application

    CERN Document Server

    Borzenkov, Mykola

    2014-01-01

    This brief includes information on the background?of and development of synthesis of various types of surface active monomers. The authors explain the importance of utilization of surface active monomers for creation of surface active polymers? and the various biomedical applications of such compounds . This brief introduces techniques for the synthesis of novel types of surface active monomers, their colloidal and polymerizable properties and application for needs of medicine and biology.

  2. A two-dimensional regularization algorithm for density profile evaluation from broadband reflectometry

    International Nuclear Information System (INIS)

    Nunes, F.; Varela, P.; Silva, A.; Manso, M.; Santos, J.; Nunes, I.; Serra, F.; Kurzan, B.; Suttrop, W.

    1997-01-01

    Broadband reflectometry is a current technique that uses the round-trip group delays of reflected frequency-swept waves to measure density profiles of fusion plasmas. The main factor that may limit the accuracy of the reconstructed profiles is the interference of the probing waves with the plasma density fluctuations: plasma turbulence leads to random phase variations and magneto hydrodynamic activity produces mainly strong amplitude and phase modulations. Both effects cause the decrease, and eventually loss, of signal at some frequencies. Several data processing techniques can be applied to filter and/or interpolate noisy group delay data obtained from turbulent plasmas with a single frequency sweep. Here, we propose a more powerful algorithm performing two-dimensional regularization (in space and time) of data provided by multiple consecutive frequency sweeps, which leads to density profiles with improved accuracy. The new method is described and its application to simulated data corrupted by noise and missing data is considered. It is shown that the algorithm improves the identification of slowly varying plasma density perturbations by attenuating the effect of fast fluctuations and noise contained in experimental data. First results obtained with this method in ASDEX Upgrade tokamak are presented. copyright 1997 American Institute of Physics

  3. LPWA using supersonic gas jet with tailored density profile

    Science.gov (United States)

    Kononenko, O.; Bohlen, S.; Dale, J.; D'Arcy, R.; Dinter, M.; Erbe, J. H.; Indorf, G.; di Lucchio, L.; Goldberg, L.; Gruse, J. N.; Karstensen, S.; Libov, V.; Ludwig, K.; Martinez de La Ossa, A.; Marutzky, F.; Niroula, A.; Osterhoff, J.; Quast, M.; Schaper, L.; Schwinkendorf, J.-P.; Streeter, M.; Tauscher, G.; Weichert, S.; Palmer, C.; Horbatiuk, Taras

    2016-10-01

    Laser driven plasma wakefield accelerators have been explored as a potential compact, reproducible source of relativistic electron bunches, utilising an electric field of many GV/m. Control over injection of electrons into the wakefield is of crucial importance in producing stable, mono-energetic electron bunches. Density tailoring of the target, to control the acceleration process, can also be used to improve the quality of the bunch. By using gas jets to provide tailored targets it is possible to provide good access for plasma diagnostics while also producing sharp density gradients for density down-ramp injection. OpenFOAM hydrodynamic simulations were used to investigate the possibility of producing tailored density targets in a supersonic gas jet. Particle-in-cell simulations of the resulting density profiles modelled the effect of the tailored density on the properties of the accelerated electron bunch. Here, we present the simulation results together with preliminary experimental measurements of electron and x-ray properties from LPWA experiments using gas jet targets and a 25 TW, 25 fs Ti:Sa laser system at DESY.

  4. Properties of ion temperature gradient and trapped electron modes in tokamak plasmas with inverted density profiles

    Science.gov (United States)

    Du, Huarong; Jhang, Hogun; Hahm, T. S.; Dong, J. Q.; Wang, Z. X.

    2017-12-01

    We perform a numerical study of linear stability of the ion temperature gradient (ITG) mode and the trapped electron mode (TEM) in tokamak plasmas with inverted density profiles. A local gyrokinetic integral equation is applied for this study. From comprehensive parametric scans, we obtain stability diagrams for ITG modes and TEMs in terms of density and temperature gradient scale lengths. The results show that, for the inverted density profile, there exists a normalized threshold temperature gradient above which the ITG mode and the TEM are either separately or simultaneously unstable. The instability threshold of the TEM for the inverted density profile is substantially different from that for normal and flat density profiles. In addition, deviations are found on the ITG threshold from an early analytic theory in sheared slab geometry with the adiabatic electron response [T. S. Hahm and W. M. Tang, Phys. Fluids B 1, 1185 (1989)]. A possible implication of this work on particle transport in pellet fueled tokamak plasmas is discussed.

  5. Comparative study of the electron density profiles in the compact torus plasma merging experiments

    International Nuclear Information System (INIS)

    Hayashiya, Hitoshi; Asaka, Takeo; Katsurai, Makoto

    2003-01-01

    Following two previous papers on the comparative studies of the electron density distributions for a single compact torus (CT) and a spherical tokamak (ST), and for the a single ST and a merged ST, a comparative study on the dynamics of the electron density profile and after the CT and ST plasma merging process was performed. The sharpness of the peak in the electron density profile around the mid-plane just after the merging of CT with a low safety factor (q value) such as RFP or spheromak is found to be related to the speed of the magnetic axis during the plasma merging process. It is also found that the electron density gradient near the plasma edge in a high q ST is larger than that of a low q CT. High q ST is found to be provided with the magnetic structure which is able to sustain a large thermal pressure by a strong j x B force. Despite these differences in the electron density profile between CT and ST during merging, the confinement characteristics evaluated from the number of electrons confined within the magnetic separatrix after the completion of the merging is almost similar between in the merging CT and in the merging ST. For all configurations, the electron density profiles after the completion of the merging are analogous to those of the corresponding single configuration produced without the merging process. (author)

  6. 2D electron density profile measurement in tokamak by laser-accelerated ion-beam probe.

    Science.gov (United States)

    Chen, Y H; Yang, X Y; Lin, C; Wang, L; Xu, M; Wang, X G; Xiao, C J

    2014-11-01

    A new concept of Heavy Ion Beam Probe (HIBP) diagnostic has been proposed, of which the key is to replace the electrostatic accelerator of traditional HIBP by a laser-driven ion accelerator. Due to the large energy spread of ions, the laser-accelerated HIBP can measure the two-dimensional (2D) electron density profile of tokamak plasma. In a preliminary simulation, a 2D density profile was reconstructed with a spatial resolution of about 2 cm, and with the error below 15% in the core region. Diagnostics of 2D density fluctuation is also discussed.

  7. Synergetic interaction between neighbouring platinum monomers in CO2 hydrogenation

    Science.gov (United States)

    Li, Hongliang; Wang, Liangbing; Dai, Yizhou; Pu, Zhengtian; Lao, Zhuohan; Chen, Yawei; Wang, Menglin; Zheng, Xusheng; Zhu, Junfa; Zhang, Wenhua; Si, Rui; Ma, Chao; Zeng, Jie

    2018-05-01

    Exploring the interaction between two neighbouring monomers has great potential to significantly raise the performance and deepen the mechanistic understanding of heterogeneous catalysis. Herein, we demonstrate that the synergetic interaction between neighbouring Pt monomers on MoS2 greatly enhanced the CO2 hydrogenation catalytic activity and reduced the activation energy relative to isolated monomers. Neighbouring Pt monomers were achieved by increasing the Pt mass loading up to 7.5% while maintaining the atomic dispersion of Pt. Mechanistic studies reveal that neighbouring Pt monomers not only worked in synergy to vary the reaction barrier, but also underwent distinct reaction paths compared with isolated monomers. Isolated Pt monomers favour the conversion of CO2 into methanol without the formation of formic acid, whereas CO2 is hydrogenated stepwise into formic acid and methanol for neighbouring Pt monomers. The discovery of the synergetic interaction between neighbouring monomers may create a new path for manipulating catalytic properties.

  8. 21 CFR 888.4220 - Cement monomer vapor evacuator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cement monomer vapor evacuator. 888.4220 Section... (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4220 Cement monomer vapor evacuator. (a) Identification. A cement monomer vapor evacuator is a device intended for use during surgery to contain or remove...

  9. Effects of triangularity on confinement, density limit and profile stiffness of H-modes on ASDEX upgrade

    International Nuclear Information System (INIS)

    Stober, J.; Gruber, O.; Kallenbach, A.; Mertens, V.; Ryter, F.; Staebler, A.; Suttrop, W.; Treutterer, W.

    2000-01-01

    At ASDEX Upgrade the influence of triangularity on the H-mode performance has been studied intensively. It has been found that confinement increases with δ for a fixed line-averaged density. Though confinement decreases with increasing density for all analysed values of δ, H-factors (ITERH-98P) at the Greenwald density could be raised to 1 for the highest δ values achieved so far. The H-mode density limit could be increased by approx. 20%. There is a scatter of about 30% on the confinement data, which is anti-correlated to the average density in the scrape-off layer or the neutral fluxes outside the plasma. For nearly all discharges analysed so far, the temperature profiles are self-similar. This indication of profile stiffness could be verified by changing the heat-flux profile by changing the beam-voltage of the neutral-beam injection (NBI) at high density. At low density, first results indicate a deviation from this stiff behaviour. (author)

  10. Ion transition heights from topside electron density profiles

    International Nuclear Information System (INIS)

    Titheridge, J.E.

    1976-01-01

    Theoretical electron density profiles are calculated for the topside ionosphere to determine the major factors controlling the profile shape. Only the mean temperature, the vertical temperature gradient and the O + /H + ion transition height are important. Vertical proton fluxes alter the ion transition height but have no other effect on the profile shape. Diffusive equilibrium profiles including only these three effects fit observed profiles, at all latitudes, to within experimental accuracy. Values of plasma temperature, temperature gradient and ion transition height hsub(T) were determined by fitting theoretical models to 60,000 experimental profiles obtained from Alouette 1 ionograms, at latitudes of 75 0 S to 85 0 N near solar minimum. Inside the plasmasphere hsub(T) varies from about 500 km on winter nights to 850 km on summer days. Diurnal variations are caused primarily by the production and loss of O + in the ionosphere. The approximately constant winter night value of hsub(T) is close to the level for chemical equilibrium. In summer hsub(T) is always above the equilibrium level, giving a continual production of protons which travel along lines of force to aid in maintaining the conjugate winter night ionosphere. Outside the plasmasphere hsub(T) is 300 to 600 km above the equilibrium level at all times. This implies a continual near-limiting upwards flux of protons which persists down to latitudes of about 60 0 at night and 50 0 during the day. (author)

  11. High-flexibility combinatorial peptide synthesis with laser-based transfer of monomers in solid matrix material.

    Science.gov (United States)

    Loeffler, Felix F; Foertsch, Tobias C; Popov, Roman; Mattes, Daniela S; Schlageter, Martin; Sedlmayr, Martyna; Ridder, Barbara; Dang, Florian-Xuan; von Bojničić-Kninski, Clemens; Weber, Laura K; Fischer, Andrea; Greifenstein, Juliane; Bykovskaya, Valentina; Buliev, Ivan; Bischoff, F Ralf; Hahn, Lothar; Meier, Michael A R; Bräse, Stefan; Powell, Annie K; Balaban, Teodor Silviu; Breitling, Frank; Nesterov-Mueller, Alexander

    2016-06-14

    Laser writing is used to structure surfaces in many different ways in materials and life sciences. However, combinatorial patterning applications are still limited. Here we present a method for cost-efficient combinatorial synthesis of very-high-density peptide arrays with natural and synthetic monomers. A laser automatically transfers nanometre-thin solid material spots from different donor slides to an acceptor. Each donor bears a thin polymer film, embedding one type of monomer. Coupling occurs in a separate heating step, where the matrix becomes viscous and building blocks diffuse and couple to the acceptor surface. Furthermore, we can consecutively deposit two material layers of activation reagents and amino acids. Subsequent heat-induced mixing facilitates an in situ activation and coupling of the monomers. This allows us to incorporate building blocks with click chemistry compatibility or a large variety of commercially available non-activated, for example, posttranslationally modified building blocks into the array's peptides with >17,000 spots per cm(2).

  12. Fast electron current density profile and diffusion studies during LHCD in PBX-M

    International Nuclear Information System (INIS)

    Jones, S.E.; Kesner, J.; Luckhardt, S.; Paoletti, F.

    1993-08-01

    Successful current profile control experiments using lower hybrid current drive (LCHD) clearly require knowledge of (1) the location of the driven fast electrons and (2) the ability to maintain that location from spreading due to radial diffusion. These issues can be addressed by examining the data from the hard x-ray camera on PBX-M, a unique diagnostic producing two-dimensional, time resolved tangential images of fast electron bremsstrahlung. Using modeling, these line-of-sight images are inverted to extract a radial fast electron current density profile. We note that ''hollow'' profiles have been observed, indicative of off-axis current drive. These profiles can then be used to calculate an upper bound for an effective fast electron diffusion constant: assuming an extremely radially narrow lower hybrid absorption profile and a transport model based on Rax and Moreau, a model fast electron current density profile is calculated and compared to the experimentally derived profile. The model diffusion constant is adjusted until a good match is found. Applied to steady-state quiescent modes on PBX-M, we obtain an upper limit for an effective diffusion constant of about D*=1.1 m 2 /sec

  13. Automated Processing of ISIS Topside Ionograms into Electron Density Profiles

    Science.gov (United States)

    Reinisch, bodo W.; Huang, Xueqin; Bilitza, Dieter; Hills, H. Kent

    2004-01-01

    Modeling of the topside ionosphere has for the most part relied on just a few years of data from topside sounder satellites. The widely used Bent et al. (1972) model, for example, is based on only 50,000 Alouette 1 profiles. The International Reference Ionosphere (IRI) (Bilitza, 1990, 2001) uses an analytical description of the graphs and tables provided by Bent et al. (1972). The Alouette 1, 2 and ISIS 1, 2 topside sounder satellites of the sixties and seventies were ahead of their times in terms of the sheer volume of data obtained and in terms of the computer and software requirements for data analysis. As a result, only a small percentage of the collected topside ionograms was converted into electron density profiles. Recently, a NASA-funded data restoration project has undertaken and is continuing the process of digitizing the Alouette/ISIS ionograms from the analog 7-track tapes. Our project involves the automated processing of these digital ionograms into electron density profiles. The project accomplished a set of important goals that will have a major impact on understanding and modeling of the topside ionosphere: (1) The TOPside Ionogram Scaling and True height inversion (TOPIST) software was developed for the automated scaling and inversion of topside ionograms. (2) The TOPIST software was applied to the over 300,000 ISIS-2 topside ionograms that had been digitized in the fkamework of a separate AISRP project (PI: R.F. Benson). (3) The new TOPIST-produced database of global electron density profiles for the topside ionosphere were made publicly available through NASA s National Space Science Data Center (NSSDC) ftp archive at . (4) Earlier Alouette 1,2 and ISIS 1, 2 data sets of electron density profiles from manual scaling of selected sets of ionograms were converted fiom a highly-compressed binary format into a user-friendly ASCII format and made publicly available through nssdcftp.gsfc.nasa.gov. The new database for the topside ionosphere established

  14. Element-specific density profiles in interacting biomembrane models

    International Nuclear Information System (INIS)

    Schneck, Emanuel; Rodriguez-Loureiro, Ignacio; Bertinetti, Luca; Gochev, Georgi; Marin, Egor; Novikov, Dmitri; Konovalov, Oleg

    2017-01-01

    Surface interactions involving biomembranes, such as cell–cell interactions or membrane contacts inside cells play important roles in numerous biological processes. Structural insight into the interacting surfaces is a prerequisite to understand the interaction characteristics as well as the underlying physical mechanisms. Here, we work with simplified planar experimental models of membrane surfaces, composed of lipids and lipopolymers. Their interaction is quantified in terms of pressure–distance curves using ellipsometry at controlled dehydrating (interaction) pressures. For selected pressures, their internal structure is investigated by standing-wave x-ray fluorescence (SWXF). This technique yields specific density profiles of the chemical elements P and S belonging to lipid headgroups and polymer chains, as well as counter-ion profiles for charged surfaces. (paper)

  15. Relativistic self-focusing of intense laser beam in thermal collisionless quantum plasma with ramped density profile

    Directory of Open Access Journals (Sweden)

    S. Zare

    2015-04-01

    Full Text Available Propagation of a Gaussian x-ray laser beam has been analyzed in collisionless thermal quantum plasma with considering a ramped density profile. In this density profile due to the increase in the plasma density, an earlier and stronger self-focusing effect is noticed where the beam width oscillates with higher frequency and less amplitude. Moreover, the effect of the density profile slope and the initial plasma density on the laser propagation has been studied. It is found that, by increasing the initial density and the ramp slope, the laser beam focuses faster with less oscillation amplitude, smaller laser spot size and more oscillations. Furthermore, a comparison is made among the laser self-focusing in thermal quantum plasma, cold quantum plasma and classical plasma. It is realized that the laser self-focusing in the quantum plasma becomes stronger in comparison with the classical regime.

  16. Profiles of radiation power density in WEGA stellarator

    International Nuclear Information System (INIS)

    Zhang, D.; Otte, M.; Giannone, L.

    2005-01-01

    On the WEGA stellarator, a 12 channel bolometer camera has been used to measure the radiation power losses of the plasma, which is heated by ECR at 2.45 GHz with a maximum power of 26 kW. The typical electron temperatures achieved are around 10 eV. The bolometer is of the Au resistor type and is positioned on the mid-plane, viewing the plasma from the low-field side with a spatial resolution of about 6 cm. The viewing angle is opened to poloidally (±47 o ) and covers the whole cross-section. Angular profiles of radiation power density (emissivity) can be achieved using the measured fluxes to the channels, which are given by the integrals along the sight lines. Using Abel inversion with maximum entropy regularisation, radial profiles of emissivity could be obtained. It is found that the angular profile of emissivity depends on the magnetic configuration, the working gas (Ar, He) and the heating scenario. Peaked and hollow emissivity profiles have been obtained by using different types of heating antenna. By changing the magnetic configuration, strong edge radiation has been observed. The largest emissivity values are obtained in the upper SOL range of Ar-discharges. This edge radiation can be reduced by shifting the flux surfaces inwards or by changing their shape at the antenna. The reconstruction of the radial profile of the emissivity was carried out in the case of a peaked angular profile with minimum edge radiation. The total radiation power was estimated by linear extrapolation of the integrated radiation power in the viewing region to the torus volume. It is typically less than 30% of the ECRH input power, but depending on the ECRH input power, again the magnetic configuration, the working gas as well as the absolute field strength on the magnetic axis. Maximum radiation losses have been obtained around 0.6·B0, where B 0 =87.5 mT is the resonant field strength of the ECRH. No evidence for impurities was obtained from spectroscopic measurements, and thus the

  17. Highly Efficient Synthesis of Allopurinol Locked Nucleic Acid Monomer by C6 Deamination of 8-Aza-7-bromo-7-deazaadenine Locked Nucleic Acid Monomer

    DEFF Research Database (Denmark)

    Kosbar, Tamer Reda El-Saeed; Sofan, M.; Abou-Zeid, L.

    2013-01-01

    An allopurinol locked nucleic acid (LNA) monomer was prepared by a novel strategy through C6 deamination of the corresponding 8-aza-7-bromo-7-deazaadenine LNA monomer with aqueous sodium hydroxide. An 8-aza-7-deazaadenine LNA monomer was also synthesized by a modification of the new synthetic...... the required LNA monomers....

  18. An analytical calculation of the axial density profile for 1-d slab expansion

    International Nuclear Information System (INIS)

    Ho, D

    1999-01-01

    Obtaining an analytical expression for the axial density profile can provide us with a quick and convenient way to evaluate the density evolution for targets with different densities and dimensions. In this note, we show that such an analytical expression can be obtained based on the self-similar solutions and the method of characteristics for 1-D slab expansion

  19. Impact of measurement approach on the quality of gamma scanning density profile in a tray type lab-scale column

    International Nuclear Information System (INIS)

    Shahabinejad, H.; Feghhi, S.A.H.; Khorsandi, M.

    2014-01-01

    This article presents a study for investigating impact of the measurement approach on the quality of gamma scanning density profile in tray type columns using experimental and computational evaluations. Experimental density profiles from the total and the photopeak count measurements, as two approaches in gamma ray column scanning technique, has been compared with the computational density profile from Monte Carlo simulation results. We used a laboratory distillation column of 51 cm diameter as an illustrative example for this investigation. 137 Cs was used as a gamma ray source with the activity of 296 MBq (8 mCi), with a NaI(Tl) detector. MCNP4C Monte Carlo code has been used for simulations. The quality of the density profile in the photopeak count approach is relatively within 155–204% better than that of the total count approach for experimental results. The same comparison for simulation results leads to a relative difference within 100–135% for the density profile. - Highlights: • The quality of density profile in gamma scanning technique has been studied. • Quality of density profile depends on the measurement approach. • A laboratory distillation column has been used as an illustrative example. • MCNP4C Monte Carlo code has been used for simulations

  20. Influence of an axial magnetic field on the density profile of capillary plasma channels

    CERN Document Server

    Ivanov, V V; Toma, E S; Bijkerk, F

    2003-01-01

    A narrow capillary plasma channel, with a sizeable depletion of the electron density on the channel axis, has been proposed to guide a laser pulse over a length of several to several tens of centimetres. We discuss the possibility to significantly improve the wave-guiding properties of such a channel by applying an axial magnetic field. Our analytical and numerical studies show that a pulsed axial magnetic field of 10 T in a hydrogen capillary plasma at a pressure of 50 Torr will reduce the on-axis plasma density by a factor of three, and the full width at half maximum of the density profile by a factor of two. The resulting parabolic plasma density profile is expected to be more efficient in guiding laser pulses.

  1. Effect of polyfunctional monomers on properties of radiation crosslinked EPDM/waste tire dust blend

    International Nuclear Information System (INIS)

    Yasin, Tariq; Khan, Sajid; Nho, Young-Chang; Ahmad, Rashid

    2012-01-01

    In this study, waste tire dust is recycled as filler and blended with ethylene-propylene diene monomer (EPDM) rubber. Three different polyfuntional monomers (PFMs) are incorporated into the standard formulation and irradiated under electron beam at different doses up to maximum of 100 kGy. The combined effects of PFMs and absorbed dose on the physical properties of EPDM/WTD blend are measured and compared with sulfur crosslinked formulation. Thermogravimetric analysis showed that radiation developed better crosslinked network with higher thermal stability than sulfur crosslinked structure. The physical properties of radiation crosslinked blend are similar to the sulfur crosslinked blend. The absence of toxic chemicals/additives in radiation crosslinked blends made them an ideal candidate for many applications such as roof sealing sheets, water retention pond, playground mat, sealing profile for windows etc. - Highlights: ► We have recycled waste tire dust and blended it with EPDM. ► EB crosslinking is carried in the presence of polyfuntional monomers. ► Radiation gave better network with higher thermal stability than sulfur. ► The absence of toxic chemicals in EB blends will increase its acceptability.

  2. Segment density profiles of polyelectrolyte brushes determined by Fourier transform ellipsometry

    Science.gov (United States)

    Biesalski, Markus; Rühe, Jürgen; Johannsmann, Diethelm

    1999-10-01

    We describe a method for the explicit determination of the segment density profile φ(z) of surface-attached polymer brushes with multiple angle of incidence null-ellipsometry. Because the refractive index contrast between the brush layer and the solvent is weak, multiple reflections are of minor influence and the ellipsometric spectrum is closely related to the Fourier transform of the refractive index profile, thereby allowing for explicit inversion of the ellipsometric data. We chose surface-attached monolayers of polymethacrylic acid (PMAA), a weak polyelectrolyte, as a model system and determined the segment density profile of this system as a function of the pH value of the surrounding medium by the Fourier method. Complementary to the Fourier analysis, fits with error functions are given as well. The brushes were prepared on the bases of high refractive index prisms with the "grafting-from" technique. In water, the brushes swell by more than a factor of 30. The swelling increases with increasing pH because of a growing fraction of dissociated acidic groups leading to a larger electrostatic repulsion.

  3. Analysis of Total Electron Content and Electron Density Profile during Different Geomagnetic Storms

    Science.gov (United States)

    Chapagain, N. P.; Rana, B.; Adhikari, B.

    2017-12-01

    Total Electron content (TEC) and electron density are the key parameters in the mitigation of ionospheric effects on radio communication system. Detail study of the TEC and electron density variations has been carried out during geomagnetic storms, with longitude and latitude, for four different locations: (13˚N -17˚N, 88˚E -98˚E), (30˚N-50˚N, 120˚W -95˚W), (29˚S-26˚S, 167˚W-163˚W,) and (60˚S-45˚S, 120˚W-105˚W) using the Gravity Recovery and Climate Experiment (GRACE) satellite observations. In order to find the geomagnetic activity, the solar wind parameters such as north-south component of inter planetary magnetic field (Bz), plasma drift velocity (Vsw), flow pressure (nPa), AE, Dst and Kp indices were obtained from Operating Mission as Nodes on the Internet (OMNI) web system. The data for geomagnetic indices have been correlated with the TEC and electron density for four different events of geomagnetic storms on 6 April 2008, 27 March 2008, 4 September 2008, and 11 October 2008. The result illustrates that the observed TEC and electron density profile significantly vary with longitudes and latitudes. This study illustrates that the values of TEC and the vertical electron density profile are influenced by the solar wind parameters associated with solar activities. The peak values of electron density and TEC increase as the geomagnetic storms become stronger. Similarly, the electron density profile varies with altitudes, which peaks around the altitude range of about 250- 350 km, depending on the strength of geomagnetic storms. The results clearly show that the peak electron density shifted to higher altitude (from about 250 km to 350 km) as the geomagnetic disturbances becomes stronger.

  4. Effect of plasma density profile of tokamak on Kelvin-Helmholtz instability

    International Nuclear Information System (INIS)

    Tang Fulin

    1984-01-01

    The purpose of this paper is to study the effect of radial distribution of plasma density profile of tokamak on Kelvin-Helmholtz instability caused by toroidal rotation. The effect of radial distribution of plasma rotational velocity on stability is also examine for comparison. It is found that within the range of tokamak parameters the only radial distribution of plasma rotational velocity cannot induce Kelvin-Helmholtz instability. On the contrary, when there is a radial distribution of plasma density, i.e. P 01 =P 0 e -tx and V 0 1 = const, plasma becomes unstable, and instability will increase proportionally to the value of t. Meanwhile when the value of t remains constant, the instability growth rate will decrease if P 0 grows or the distance between plasma and wall of container decreases too. It shows that the Kelvin-Helmoltz instability is not only influenced by the steepness of density profile but also by the inertia of plasma in central region, which is helpful for depressing the instability. (author). 5 refs, 4 figs, 2 tabs

  5. Electron density profiles in the background of LF absorption during Forbush-decrease and PSE

    International Nuclear Information System (INIS)

    Satori, G.

    1989-01-01

    Based on the simulation of different Forbush decrease and particle precipitation effects in the D region, electron density profiles in the mid-latitudes the ionospheric absorption of low frequency (LF) radio waves was determined. The absorption variations at different frequenceis are strongly affected by the shape of the electron density profile. A structure appears which sometimes resembles the letter S (in a sloping form). Both the height (around 70 to 72 km) and the depth of the local minimum in the electron density contribute to the computed absorption changes of various degree at different frequencies. In this way several observed special absorption events can be interpreted

  6. Flare plasma density determination using observed temperature profiles

    International Nuclear Information System (INIS)

    Garcia, H.A.

    1986-01-01

    Observed electron temperature variations derived from flux intensity ratios of whole-disk continuum soft X-ray spectra recorded by GOES satellites are presently subjected to an analysis that is based on the nonequilibrium energy balance equation in order to obtain the physical properties of a large solar flare from onset through the gradual phase. A self-similar formalism which reduces the nonlinear, second-order PDE in length and time to a more tractable, nonlinear, first-order Ricatti equation is invoked. Plasma density is the principal unknown variable contained in the Ricatti equation, which also contains first-order time derivatives and first- and second-order spatial derivatives of temperature. This methodology is presently applied to the moderate size flare of January 28, 1982, for which a density profile is deduced under various parametric conditions. 37 references

  7. Step growth of two flexible ABf monomers

    DEFF Research Database (Denmark)

    Cameron, Colin; Fawcett, Allan H.; Hetherington, Cecil R.

    2000-01-01

    A three-dimensional lattice model was used to simulate the competition between the growth of hyperbranched structures and cycle formation that occurs when flexible ABf monomers undergo step growth. The monomers in the model are mapped onto several lattice sites. The effect of functionality...

  8. Thermodynamics of swelling of latex particles with two monomers

    NARCIS (Netherlands)

    Maxwell, I.A.; Kurja, J.; van Doremaele, G.H.J.; German, A.L.

    1992-01-01

    The partitioning of 2 monomers between the latex particle, monomer droplet, and aq. phases of an emulsion polymer latex are measured at satn. swelling of the latex particle phase (corresponding to intervals I and II of an emulsion polymn.). The monomer (Me acrylate, Bu acrylate, styrene) and polymer

  9. Real-time evaluation of electron and current density profile parameters on TEXTOR

    International Nuclear Information System (INIS)

    Bruessau, W.D.; Soltwisch, H.

    1985-08-01

    The shapes of electron and current density profiles are monitored in real-time mode in order to get rapid qualitative information on the development of a TEXTOR tokamak plasma. The profiles are described by form parameters which relate to the signals of a 9-channel FIR-polari/interferometer in simple mathematical formulae. These profile parameters are obtained by real-time conversion of measured quantities for display on a storage oscilloscope or on a chart recorder. The application of the parameters is demonstrated in some examples. (orig.)

  10. A thermodynamic perturbation theory for the surface tension and ion density profile of a liquid metal

    International Nuclear Information System (INIS)

    Evans, R.; Kumaravadivel, R.

    1976-01-01

    A simple scheme for determining the ion density profile and the surface tension of a liquid metal is described. Assuming that the interaction between metallic pseudo-ions is of the form introduced by Evans, an approximate expression for the excess free energy of the system is derived using the thermodynamic perturbation theory of Weeks, Chandler and Anderson. This excess free energy is then minimized with respect to a parameter which specifies the ion density profile, and the surface tension is given directly. From a consideration of the dependence of the interionic forces on the electron density it is predicted that the ions should take up a very steep density profile at the liquid metal surface. This behaviour is contrasted with that to be expected for rare-gas fluids in which the interatomic forces are density-independent. The values of the surface tension calculated for liquid Na, K and Al from a simplified version of the theory are in reasonable agreement with experiment. (author)

  11. Density profile effects on confinement and MHD stability of currentless NBI plasmas in Heliotron E

    International Nuclear Information System (INIS)

    Sudo, Shigeru; Zushi, Hideki; Kondo, Katsumi

    1993-01-01

    Density profile effects on confinement and MHD stability of currentless NBI plasmas in Heliotron E are studied. The peaked density profile produced by pellet injection increases the stored energy by 20-30% compared to the gas puffed plasmas which obey the empirical stellarator/heliotron scaling in a moderate density range. In contrast to confinement, the peaked pressure profile tends to destabilize the plasma. By limiter insertion, MHD instability occurs (seems to locate near ι/2π=1) even in case of low β (β 0 ≤1%, where β 0 is the central β value) plasmas. On the other hand, the mode of m/n=3/2 at ι/2π=2/3, seems to be a key parameter to the major MHD instability in case of high β (β 0 ≥2%) plasmas. (author)

  12. 1 / n Expansion for the Number of Matchings on Regular Graphs and Monomer-Dimer Entropy

    Science.gov (United States)

    Pernici, Mario

    2017-08-01

    Using a 1 / n expansion, that is an expansion in descending powers of n, for the number of matchings in regular graphs with 2 n vertices, we study the monomer-dimer entropy for two classes of graphs. We study the difference between the extensive monomer-dimer entropy of a random r-regular graph G (bipartite or not) with 2 n vertices and the average extensive entropy of r-regular graphs with 2 n vertices, in the limit n → ∞. We find a series expansion for it in the numbers of cycles; with probability 1 it converges for dimer density p diverges as |ln(1-p)| for p → 1. In the case of regular lattices, we similarly expand the difference between the specific monomer-dimer entropy on a lattice and the one on the Bethe lattice; we write down its Taylor expansion in powers of p through the order 10, expressed in terms of the number of totally reducible walks which are not tree-like. We prove through order 6 that its expansion coefficients in powers of p are non-negative.

  13. Bayesian modeling of JET Li-BES for edge electron density profiles using Gaussian processes

    Science.gov (United States)

    Kwak, Sehyun; Svensson, Jakob; Brix, Mathias; Ghim, Young-Chul; JET Contributors Collaboration

    2015-11-01

    A Bayesian model for the JET lithium beam emission spectroscopy (Li-BES) system has been developed to infer edge electron density profiles. The 26 spatial channels measure emission profiles with ~15 ms temporal resolution and ~1 cm spatial resolution. The lithium I (2p-2s) line radiation in an emission spectrum is calculated using a multi-state model, which expresses collisions between the neutral lithium beam atoms and the plasma particles as a set of differential equations. The emission spectrum is described in the model including photon and electronic noise, spectral line shapes, interference filter curves, and relative calibrations. This spectral modeling gets rid of the need of separate background measurements for calculating the intensity of the line radiation. Gaussian processes are applied to model both emission spectrum and edge electron density profile, and the electron temperature to calculate all the rate coefficients is obtained from the JET high resolution Thomson scattering (HRTS) system. The posterior distributions of the edge electron density profile are explored via the numerical technique and the Markov chain Monte Carlo (MCMC) samplings. See the Appendix of F. Romanelli et al., Proceedings of the 25th IAEA Fusion Energy Conference 2014, Saint Petersburg, Russia.

  14. Electron momentum density and Compton profile by a semi-empirical approach

    Science.gov (United States)

    Aguiar, Julio C.; Mitnik, Darío; Di Rocco, Héctor O.

    2015-08-01

    Here we propose a semi-empirical approach to describe with good accuracy the electron momentum densities and Compton profiles for a wide range of pure crystalline metals. In the present approach, we use an experimental Compton profile to fit an analytical expression for the momentum densities of the valence electrons. This expression is similar to a Fermi-Dirac distribution function with two parameters, one of which coincides with the ground state kinetic energy of the free-electron gas and the other resembles the electron-electron interaction energy. In the proposed scheme conduction electrons are neither completely free nor completely bound to the atomic nucleus. This procedure allows us to include correlation effects. We tested the approach for all metals with Z=3-50 and showed the results for three representative elements: Li, Be and Al from high-resolution experiments.

  15. Universal analytical scattering form factor for shell-, core-shell, or homogeneous particles with continuously variable density profile shape.

    Science.gov (United States)

    Foster, Tobias

    2011-09-01

    A novel analytical and continuous density distribution function with a widely variable shape is reported and used to derive an analytical scattering form factor that allows us to universally describe the scattering from particles with the radial density profile of homogeneous spheres, shells, or core-shell particles. Composed by the sum of two Fermi-Dirac distribution functions, the shape of the density profile can be altered continuously from step-like via Gaussian-like or parabolic to asymptotically hyperbolic by varying a single "shape parameter", d. Using this density profile, the scattering form factor can be calculated numerically. An analytical form factor can be derived using an approximate expression for the original Fermi-Dirac distribution function. This approximation is accurate for sufficiently small rescaled shape parameters, d/R (R being the particle radius), up to values of d/R ≈ 0.1, and thus captures step-like, Gaussian-like, and parabolic as well as asymptotically hyperbolic profile shapes. It is expected that this form factor is particularly useful in a model-dependent analysis of small-angle scattering data since the applied continuous and analytical function for the particle density profile can be compared directly with the density profile extracted from the data by model-free approaches like the generalized inverse Fourier transform method. © 2011 American Chemical Society

  16. Fast-scan monitor examines neutral-beam ion-density profile

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    All of the magnetic mirror confinement fusion experiments at LLL and at other laboratories depend on pulsed, energetic neutral-beam injection for fueling and imparting energy to the trapped plasma for density build-up and stability studies. It is vital to be able to monitor how well the injected ion beam is aimed and focused. To do this, we have designed an ion-beam current-density profile monitor that uses a commercial minimodular data acquisition system. Our prototype model monitors a single 20-kV, 50-A, 10-ms beam. However, the method is applicable to any number of beams with similar sampling target arrays. Also, the electronics can be switched to monitor any one of several target collectors

  17. Avalanche consumption and the stationary regions of the density profile around the droplets in the theory of condensation

    OpenAIRE

    Kurasov, V.

    1998-01-01

    The contradiction between the stationary aproach to the density profile and the avalanche character of the metastable phase consumption is investigated. The exact solution for the metastable phase profile is obtained. The reconsidered value for the special parameter responsible for the hierarchy in the structure of the density profile around the droplet is presented.

  18. New monomers for high performance polymers

    Science.gov (United States)

    Gratz, Roy F.

    1993-01-01

    This laboratory has been concerned with the development of new polymeric materials with high thermo-oxidative stability for use in the aerospace and electronics industries. Currently, there is special emphasis on developing matrix resins and composites for the high speed civil transport (HSCT) program. This application requires polymers that have service lifetimes of 60,000 hr at 350 F (177 C) and that are readily processible into void-free composites, preferably by melt-flow or powder techniques that avoid the use of high boiling solvents. Recent work has focused on copolymers which have thermally stable imide groups separated by flexible arylene ether linkages, some with trifluoromethyl groups attached to the aromatic rings. The presence of trifluoromethyl groups in monomers and polymers often improves their solubility and processibility. The goal of this research was to synthesize several new monomers containing pendant trifluoromethyl groups and to incorporate these monomers into new imide/arylene ether copolymers. Initially, work was begun on the synthesis of three target compounds. The first two, 3,5-dihydroxybenzo trifluoride and 3-amino 5-hydroxybenzo trifluoride, are intermediates in the synthesis of more complex monomers. The third, 3,5-bis (3-amino-phenoxy) benzotrifluoride, is an interesting diamine that could be incorporated into a polyimide directly.

  19. Measurements of density profile evolution during the stably-stratified filling of an open enclosure

    International Nuclear Information System (INIS)

    Tarawneh, Constantine M.; Homan, K.O.

    2008-01-01

    The stably-stratified filling of an open enclosure produces an interfacial gradient layer which is transported through the enclosure with the bulk flow. The evolution of this interfacial layer is strongly time-dependent and is driven by the nature of the interaction between the internal gravity waves and the inlet-driven interfacial shear. Measurements of density profile evolution have been completed for a rectangular enclosure with a single corner inlet and density variation produced by saline concentration. This system serves as a mass transfer analog to large-scale, thermally-stratified energy storage devices, preserving dynamic similitude in a laboratory-scale system. The experiments covered jet Reynolds numbers of 200-2200 and Froude numbers of 0.06-0.6 in an enclosure with a width 23 times the jet inlet height. The density profiles are seen to be strongly asymmetric and exhibit growth rates significantly different than due to simple one-dimensional molecular diffusion. In addition, shadowgraph and hydrogen bubble visualizations of the density and velocity fields in the gradient layer show the persistence of complex multi-dimensional flow structure even at relatively late stages of the filling process when the gradient layer has been transported well away from the enclosure inlet. The evolution of the vertical density profile has been compared quantitatively to a quasi one-dimensional model based upon empirical diffusivity coefficients

  20. The diverse density profiles of galaxy clusters with self-interacting dark matter plus baryons

    Science.gov (United States)

    Robertson, Andrew; Massey, Richard; Eke, Vincent; Tulin, Sean; Yu, Hai-Bo; Bahé, Yannick; Barnes, David J.; Bower, Richard G.; Crain, Robert A.; Dalla Vecchia, Claudio; Kay, Scott T.; Schaller, Matthieu; Schaye, Joop

    2018-05-01

    We present the first simulated galaxy clusters (M200 > 1014 M⊙) with both self-interacting dark matter (SIDM) and baryonic physics. They exhibit a greater diversity in both dark matter and stellar density profiles than their counterparts in simulations with collisionless dark matter (CDM), which is generated by the complex interplay between dark matter self-interactions and baryonic physics. Despite variations in formation history, we demonstrate that analytical Jeans modelling predicts the SIDM density profiles remarkably well, and the diverse properties of the haloes can be understood in terms of their different final baryon distributions.

  1. Density profile measurements from a two-gun plasma focus device

    International Nuclear Information System (INIS)

    Tzeng, C.C.; Yen, C.K.; Yeh, T.R.; Kuo, Y.Y.; Shang, D.J.; Yu, Y.Z.; Hou, W.S.

    1990-01-01

    The dynamics of the plasma evolution in a two-gun plasma focus device has been studied using the laser shadowgraphy as well as the laser interferometry. The experiments were carried out from a 700 kJ two-gun plasma focus device reported earlier, which consisted of a pair of Mather type coaxial electrodes connected muzzle to muzzle. Previous results indicated that the simultaneous formation of the two deuterium plasma foci occurred earlier and then after ∼ 100 ns a disk-shaped plasma of ∼ 1.5 cm in diameter appeared in the middle region between the anodes. It is, therefore, the authors' goal to study the density profiles in the plasma foci and the middle region in order to understand further the formation of the plasma foci and their time evolution. The laser shadowgraphy was done with a XeCl excimer pumped dye laser system which operated at 550 nm with pulse width of ∼ 10 ns. The laser interferometry, on the other hand, was carried out using a TEA-TEA oscillator-amplifier N 2 -laser system with 337.1 nm and subnano-second pulse width. Both results show that the maximum electron density is ≥2 x 10 19 cm -3 and, in addition, the growth of the hydrodynamic instabilities are observed. These results together with the detailed density profiles are presented and discussed

  2. Modification of K-line emission profiles in laser-created solid-density plasmas

    International Nuclear Information System (INIS)

    Sengebusch, A.; Reinholz, H.; Roepke, G.

    2010-01-01

    Complete text of publication follows. X-ray emissions in the keV energy range have shown to be suitable radiation to investigate the properties of laser-created solid-density plasmas. We use the modifications of inner shell transitions due to the environment to characterize these plasmas. A theoretical treatment of spectral line profiles based on a self-consistent ion sphere model is applied on moderately ionized mid-Z materials, such as titanium, silicon and chlorine. We observe large contributions of satellite transitions due to M-shell ionization and excitation. To determine the composition a mixture of various excited and ionized ionic states embedded in a plasma has to be considered. Plasma polarization effects that cause shifts of the emission and ionization energies are taken into account. K-line profiles are calculated for bulk temperatures up to 100 eV and free electron densities up to 10 24 cm -3 in order to analyze recent measurements with respect to the plasma parameters of electron heated target regions. Moreover, in high-intensity laser-matter interactions, inevitable prepulses are likely to create preplasma and shocks within the target before the main pulse arrives. We investigate the influence of density gradients due to prepulses on the spectral profiles. Further, radial bulk temperature distributions as well the composition of the created warm dense matter are inferred.

  3. Computational Modeling and Theoretical Calculations on the Interactions between Spermidine and Functional Monomer (Methacrylic Acid in a Molecularly Imprinted Polymer

    Directory of Open Access Journals (Sweden)

    Yujie Huang

    2015-01-01

    Full Text Available This paper theoretically investigates interactions between a template and functional monomer required for synthesizing an efficient molecularly imprinted polymer (MIP. We employed density functional theory (DFT to compute geometry, single-point energy, and binding energy (ΔE of an MIP system, where spermidine (SPD and methacrylic acid (MAA were selected as template and functional monomer, respectively. The geometry was calculated by using B3LYP method with 6-31+(d basis set. Furthermore, 6-311++(d, p basis set was used to compute the single-point energy of the above geometry. The optimized geometries at different template to functional monomer molar ratios, mode of bonding between template and functional monomer, changes in charge on natural bond orbital (NBO, and binding energy were analyzed. The simulation results show that SPD and MAA form a stable complex via hydrogen bonding. At 1 : 5 SPD to MAA ratio, the binding energy is minimum, while the amount of transferred charge between the molecules is maximum; SPD and MAA form a stable complex at 1 : 5 molar ratio through six hydrogen bonds. Optimizing structure of template-functional monomer complex, through computational modeling prior synthesis, significantly contributes towards choosing a suitable pair of template-functional monomer that yields an efficient MIP with high specificity and selectivity.

  4. Plasma density profiles and finite bandwidth effects on electron heating

    International Nuclear Information System (INIS)

    Spielman, R.B.; Mizuno, K.; DeGroot, J.S.; Bollen, W.M.; Woo, W.

    1980-01-01

    Intense, p-polarized microwaves are incident on an inhomogeneous plasma in a cylindrical waveguide. Microwaves are mainly absorbed by resonant absorption near the critical surface (where the plasma frequency, ω/sub pe/, equals the microwave frequency, ω/sub o/). The localized plasma waves strongly modify the plasma density. Step-plateau density profiles or a cavity are created depending on the plasma flow speed. Hot electron production is strongly affected by the microwave bandwidth. The hot electron temperature varies as T/sub H/ is proportional to (Δ ω/ω) -0 25 . As the hot electron temperature decreases with increasing driver bandwidth, the hot electron density increases. This increase is such that the heat flux into the overdense region (Q is proportional to eta/sub H/T/sub H/ 3 2 ) is nearly constant

  5. The effect of monomer molecular weight on grafting reaction

    International Nuclear Information System (INIS)

    Wu Minghong; Ding Zhongli; Ma Zueteh

    1995-01-01

    In this paper, some condensed ethylene glycol acrylate monomers with different molecular weight being grafted to the PE film by means of pre-irradiation is reported. The effect of molecular weight of monomer on grafting reaction and the hydrophilicity of grafting sample have been discussed. The experimental results show: molar degrees of grafting decreased non-linearly with the increasement of molecular weight of monomer, the grafting reaction of polymer is greater effected by the swelling degree of PE film, the greater the swelling degree of grafting material, the higher the grating degree grafting is, the initial rate of grafting reaction decreased with the increasement of molecular weight of monomer. (author)

  6. Vacuum heating evaluation for plasmas of exponentially decreasing density profile

    International Nuclear Information System (INIS)

    Pestehe, S.J.; Mohammadnejad, M.

    2008-01-01

    Ultra-short pulse lasers have opened a regime of laser-plasma interaction where plasmas have scale lengths shorter than the laser wavelength and allow the possibility of generating near-solid density plasmas. The interaction of high-intensity laser beams with sharply bounded high-density and small scale length plasmas is considered. Absorption of the laser energy associated with the mechanism of dragging electrons out of the plasma into the vacuum and sending them back into the plasma with the electric field component along the density gradient, so called vacuum heating, is studied. An exponentially decreasing electron density profile is assumed. The vector potential of the electromagnetic field propagating through the plasma is calculated and the behaviour of the electric and magnetic components of the electromagnetic field is studied. The fraction of laser power absorbed in this process is calculated and plotted versus the laser beam incidence angle, illumination energy, and the plasma scale length

  7. Measurement of heat load density profile on acceleration grid in MeV-class negative ion accelerator.

    Science.gov (United States)

    Hiratsuka, Junichi; Hanada, Masaya; Kojima, Atsushi; Umeda, Naotaka; Kashiwagi, Mieko; Miyamoto, Kenji; Yoshida, Masafumi; Nishikiori, Ryo; Ichikawa, Masahiro; Watanabe, Kazuhiro; Tobari, Hiroyuki

    2016-02-01

    To understand the physics of the negative ion extraction/acceleration, the heat load density profile on the acceleration grid has been firstly measured in the ITER prototype accelerator where the negative ions are accelerated to 1 MeV with five acceleration stages. In order to clarify the profile, the peripheries around the apertures on the acceleration grid were separated into thermally insulated 34 blocks with thermocouples. The spatial resolution is as low as 3 mm and small enough to measure the tail of the beam profile with a beam diameter of ∼16 mm. It was found that there were two peaks of heat load density around the aperture. These two peaks were also clarified to be caused by the intercepted negative ions and secondary electrons from detailed investigation by changing the beam optics and gas density profile. This is the first experimental result, which is useful to understand the trajectories of these particles.

  8. Measurement of heat load density profile on acceleration grid in MeV-class negative ion accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Hiratsuka, Junichi, E-mail: hiratsuka.junichi@jaea.go.jp; Hanada, Masaya; Kojima, Atsushi; Umeda, Naotaka; Kashiwagi, Mieko; Yoshida, Masafumi; Nishikiori, Ryo; Ichikawa, Masahiro; Watanabe, Kazuhiro; Tobari, Hiroyuki [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka 311-0193 (Japan); Miyamoto, Kenji [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan)

    2016-02-15

    To understand the physics of the negative ion extraction/acceleration, the heat load density profile on the acceleration grid has been firstly measured in the ITER prototype accelerator where the negative ions are accelerated to 1 MeV with five acceleration stages. In order to clarify the profile, the peripheries around the apertures on the acceleration grid were separated into thermally insulated 34 blocks with thermocouples. The spatial resolution is as low as 3 mm and small enough to measure the tail of the beam profile with a beam diameter of ∼16 mm. It was found that there were two peaks of heat load density around the aperture. These two peaks were also clarified to be caused by the intercepted negative ions and secondary electrons from detailed investigation by changing the beam optics and gas density profile. This is the first experimental result, which is useful to understand the trajectories of these particles.

  9. Coupling of g proteins to reconstituted monomers and tetramers of the M2 muscarinic receptor.

    Science.gov (United States)

    Redka, Dar'ya S; Morizumi, Takefumi; Elmslie, Gwendolynne; Paranthaman, Pranavan; Shivnaraine, Rabindra V; Ellis, John; Ernst, Oliver P; Wells, James W

    2014-08-29

    G protein-coupled receptors can be reconstituted as monomers in nanodiscs and as tetramers in liposomes. When reconstituted with G proteins, both forms enable an allosteric interaction between agonists and guanylyl nucleotides. Both forms, therefore, are candidates for the complex that controls signaling at the level of the receptor. To identify the biologically relevant form, reconstituted monomers and tetramers of the purified M2 muscarinic receptor were compared with muscarinic receptors in sarcolemmal membranes for the effect of guanosine 5'-[β,γ-imido]triphosphate (GMP-PNP) on the inhibition of N-[(3)H]methylscopolamine by the agonist oxotremorine-M. With monomers, a stepwise increase in the concentration of GMP-PNP effected a lateral, rightward shift in the semilogarithmic binding profile (i.e. a progressive decrease in the apparent affinity of oxotremorine-M). With tetramers and receptors in sarcolemmal membranes, GMP-PNP effected a vertical, upward shift (i.e. an apparent redistribution of sites from a state of high affinity to one of low affinity with no change in affinity per se). The data were analyzed in terms of a mechanistic scheme based on a ligand-regulated equilibrium between uncoupled and G protein-coupled receptors (the "ternary complex model"). The model predicts a rightward shift in the presence of GMP-PNP and could not account for the effects at tetramers in vesicles or receptors in sarcolemmal membranes. Monomers present a special case of the model in which agonists and guanylyl nucleotides interact within a complex that is both constitutive and stable. The results favor oligomers of the M2 receptor over monomers as the biologically relevant state for coupling to G proteins. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Measurement of the density profile of pure and seeded molecular beams by femtosecond ion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Congsen [LaserLaB Amsterdam, VU University Amsterdam, de Boelelaan 1083, 1081 HV Amsterdam (Netherlands); Department of Physics, National University of Defense Technology, Changsha 410073 (China); Janssen, Maurice H. M. [LaserLaB Amsterdam, VU University Amsterdam, de Boelelaan 1083, 1081 HV Amsterdam (Netherlands)

    2015-02-15

    Here, we report on femtosecond ion imaging experiments to measure the density profile of a pulsed supersonic molecular beam. Ion images are measured for both a molecular beam and bulk gas under identical experimental conditions via femtosecond multiphoton ionization of Xe atoms. We report the density profile of the molecular beam, and the measured absolute density is compared with theoretical calculations of the centre line beam density. Subsequently, we discuss reasons accounting for the differences between measurements and calculations and propose that strong skimmer interference is the most probable cause for the differences. Furthermore, we report on experiments measuring the centre line density of seeded supersonic beams. The femtosecond ion images show that seeding the heavy Xe atom at low relative seed fractions (1%-10%) in a light carrier gas like Ne results in strong relative enhancements of up to two orders of magnitude.

  11. Radical Copolymerization Kinetics of Bio-Renewable Butyrolactone Monomer in Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Sharmaine B. Luk

    2017-10-01

    Full Text Available The radical copolymerization kinetics of acrylamide (AM and the water-soluble monomer sodium 4-hydroxy-4-methyl-2-methylene butanoate (SHMeMB, formed by saponification of the bio-sourced monomer γ-methyl-α-methylene-γ-butyrolactone (MeMBL, are investigated to explain the previously reported slow rates of reaction during synthesis of superabsorbent hydrogels. Limiting conversions were observed to decrease with increased temperature during SHMeMB homopolymerization, suggesting that polymerization rate is limited by depropagation. Comonomer composition drift also increased with temperature, with more AM incorporated into the copolymer due to SHMeMB depropagation. Using previous estimates for the SHMeMB propagation rate coefficient, the conversion profiles were used to estimate rate coefficients for depropagation and termination (kt. The estimate for kt,SHMeMB was found to be of the same order of magnitude as that recently reported for sodium methacrylate, with the averaged copolymerization termination rate coefficient dominated by the presence of SHMeMB in the system. In addition, it was found that depropagation still controlled the SHMeMB polymerization rate at elevated temperatures in the presence of added salt.

  12. Photopolymerizable silicone monomers, oligomers, and resins

    International Nuclear Information System (INIS)

    Jacobine, A.F.; Nakos, S.T.

    1992-01-01

    The purpose of this chapter is to acquaint the general photopolymer researcher with the historical development of the chemistry and technology of photopolymerizable silicone monomers, fluids, and resins. The current status of research in these areas is assessed. The focus of this chapter is not only on the polymer chemistry and application of this technology, but also on important aspects of the synthetic chemistry involved in the preparation of UV-curable silicone monomers, oligomers, and resins. 236 refs., 6 tabs

  13. The Splashback Feature around DES Galaxy Clusters: Galaxy Density and Weak Lensing Profiles

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chihway; et al.

    2017-10-18

    Splashback refers to the process of matter that is accreting onto a dark matter halo reaching its first orbital apocenter and turning around in its orbit. The cluster-centric radius at which this process occurs, r_sp, defines a halo boundary that is connected to the dynamics of the cluster, in contrast with other common halo boundary definitions such as R_200. A rapid decline in the matter density profile of the halo is expected near r_sp. We measure the galaxy number density and weak lensing mass profiles around RedMapper galaxy clusters in the first year Dark Energy Survey (DES) data. For a cluster sample with mean mass ~2.5 x 10^14 solar masses, we find strong evidence of a splashback-like steepening of the galaxy density profile and measure r_sp=1.16 +/- 0.08 Mpc/h, consistent with earlier SDSS measurements of More et al. (2016) and Baxter et al. (2017). Moreover, our weak lensing measurement demonstrates for the first time the existence of a splashback-like steepening of the matter profile of galaxy clusters. We measure r_sp=1.28 +/- 0.18 Mpc/h from the weak lensing data, in good agreement with our galaxy density measurements. Applying our analysis to different cluster and galaxy samples, we find that consistent with LambdaCDM simulations, r_sp scales with R_200m and does not evolve with redshift over the redshift range of 0.3--0.6. We also find that potential systematic effects associated with the RedMapper algorithm may impact the location of r_sp, in particular the choice of scale used to estimate cluster richness. We discuss progress needed to understand the systematic uncertainties and fully exploit forthcoming data from DES and future surveys, emphasizing the importance of more realistic mock catalogs and independent cluster samples.

  14. Comparison of the observed results of the electron density profiles with the IRI90

    International Nuclear Information System (INIS)

    Zhang Manlian; Radicella, S.M.; Dai Kailiang

    1996-01-01

    The daily and composite profiles and the thickness parameter of the electron density profiles are compared with the results of IRI90 for the stations of Ramey (15.8 deg. N, 292.9 deg. E), Wuchang (30.6 deg. N, 114.3 deg. E), Chongqing (29.5 deg. N, 106.4 deg. E) and Wrumchi (43.8 deg. N, 87.6 deg. E). It is found that the electron density profiles produced by IRI90, both with the old Standard B0 and the new Gulyaeva-B0 thickness parameter, are too thick below F2-peak compared with the observed results. It is also shown that the IRI90 results show a very poor agreement with the observed results for the intermediate (F1) layer of the ionosphere. (author). 1 ref., 4 figs,

  15. Dynamic conformations of nucleophosmin (NPM1 at a key monomer-monomer interface affect oligomer stability and interactions with granzyme B.

    Directory of Open Access Journals (Sweden)

    Wei D Duan-Porter

    Full Text Available Nucleophosmin (NPM1 is an abundant, nucleolar tumor antigen with important roles in cell proliferation and putative contributions to oncogenesis. Wild-type NPM1 forms pentameric oligomers through interactions at the amino-terminal core domain. A truncated form of NPM1 found in some hepatocellular carcinoma tissue formed an unusually stable oligomer and showed increased susceptibility to cleavage by granzyme B. Initiation of translation at the seventh methionine generated a protein (M7-NPM that shared all these properties. We used deuterium exchange mass spectrometry (DXMS to perform a detailed structural analysis of wild-type NPM1 and M7-NPM, and found dynamic conformational shifts or local "unfolding" at a specific monomer-monomer interface which included the β-hairpin "latch." We tested the importance of interactions at the β-hairpin "latch" by replacing a conserved tyrosine in the middle of the β-hairpin loop with glutamic acid, generating Y67E-NPM. Y67E-NPM did not form stable oligomers and further, prevented wild-type NPM1 oligomerization in a dominant-negative fashion, supporting the critical role of the β-hairpin "latch" in monomer-monomer interactions. Also, we show preferential cleavage by granzyme B at one of two available aspartates (either D161 or D122 in M7-NPM and Y67E-NPM, whereas wild-type NPM1 was cleaved at both sites. Thus, we observed a correlation between the propensity to form oligomers and granzyme B cleavage site selection in nucleophosmin proteins, suggesting that a small change at an important monomer-monomer interface can affect conformational shifts and impact protein-protein interactions.

  16. Polymerization of impregnated monomer in wood by microwave irradiation

    International Nuclear Information System (INIS)

    Kawase, Kaoru; Hayakawa, Kiyoshi

    1976-01-01

    The manufacturing of a wood-plastic combination (WPC) by irradiation of microwave (2,450 and 915 +- 50 MHz) or gamma-ray was carried out. After the impregnation of dry woods (Hinoki: Chamaecyparis obtusa Endl., Buna: Acer mono Maxim., and Kaede: Fagus crenata Blume) with the mixture of the vinyl monomers and chemical reagents, the monomer in wood was polymerized by irradiation. In case of polymerization with microwave (2,450 MHz) the effect of oxygen was not recognized, but in the case of gamma-ray the rate of polymerization remarkably decreased in the presence of oxygen. The polymerization of various monomers was carried out also in the air, and the conversions of styrene, methyl-, ethyl-, n-propyl-, and n-butyl-methacrylate were 51.8 -- 89.1%, but that of vinyl acetate was lower (4.3 -- 8.2%). The conversion of monomers with irradiation of 915 MHz microwave was very low (2.6 -- 33.5%). The conversion of monomers increased when toluylene diisocyanate was added in the monomers. The percentage of extraction with hot benzene of WPC (chip) decreased by the addition of toluylene diisocyanate. It was concluded from C.H.N. analyses that the reaction took place among the wood, toluylene diisocyanate and methyl methacrylate. (auth.)

  17. Electron density profile measurements from hydrogen line intensity ratio method in Versatile Experimental Spherical Torus

    Energy Technology Data Exchange (ETDEWEB)

    Kim, YooSung; Shi, Yue-Jiang, E-mail: yjshi@snu.ac.kr; Yang, Jeong-hun; Kim, SeongCheol; Kim, Young-Gi; Dang, Jeong-Jeung; Yang, Seongmoo; Jo, Jungmin; Chung, Kyoung-Jae [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Oh, Soo-Ghee [Division of Energy Systems Research, Ajou University, Suwon 442-749 (Korea, Republic of); Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Center for Advanced Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

    2016-11-15

    Electron density profiles of versatile experiment spherical torus plasmas are measured by using a hydrogen line intensity ratio method. A fast-frame visible camera with appropriate bandpass filters is used to detect images of Balmer line intensities. The unique optical system makes it possible to take images of H{sub α} and H{sub β} radiation simultaneously, with only one camera. The frame rate is 1000 fps and the spatial resolution of the system is about 0.5 cm. One-dimensional local emissivity profiles have been obtained from the toroidal line of sight with viewing dumps. An initial result for the electron density profile is presented and is in reasonable agreement with values measured by a triple Langmuir probe.

  18. Electron density profile reconstruction by maximum entropy method with multichannel HCN laser interferometer system on SPAC VII

    International Nuclear Information System (INIS)

    Kubo, S.; Narihara, K.; Tomita, Y.; Hasegawa, M.; Tsuzuki, T.; Mohri, A.

    1988-01-01

    A multichannel HCN laser interferometer system has been developed to investigate the plasma electron confinement properties in SPAC VII device. Maximum entropy method is applied to reconstruct the electron density profile from measured line integrated data. Particle diffusion coefficient in the peripheral region of the REB ring core spherator was obtained from the evolution of the density profile. (author)

  19. Influence of template/functional monomer/cross‐linking monomer ratio on particle size and binding properties of molecularly imprinted nanoparticles

    DEFF Research Database (Denmark)

    Yoshimatsu, Keiichi; Yamazaki, Tomohiko; Chronakis, Ioannis S.

    2012-01-01

    A series of molecularly imprinted polymer nanoparticles have been synthesized employing various template/functional monomer/crosslinking monomer ratio and characterized in detail to elucidate the correlation between the synthetic conditions used and the properties (e.g., particle size and templat...... tuning of particle size and binding properties are required to fit practical applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012...

  20. Impact of Te and ne on edge current density profiles in ELM mitigated regimes on ASDEX Upgrade

    Science.gov (United States)

    Dunne, M. G.; Rathgeber, S.; Burckhart, A.; Fischer, R.; Giannone, L.; McCarthy, P. J.; Schneider, P. A.; Wolfrum, E.; the ASDEX Upgrade Team

    2015-01-01

    ELM resolved edge current density profiles are reconstructed using the CLISTE equilibrium code. As input, highly spatially and temporally resolved edge electron temperature and density profiles are used in addition to data from the extensive set of external poloidal field measurements available at ASDEX Upgrade, flux loop difference measurements, and current measurements in the scrape-off layer. Both the local and flux surface averaged current density profiles are analysed for several ELM mitigation regimes. The focus throughout is on the impact of altered temperature and density profiles on the current density. In particular, many ELM mitigation regimes rely on operation at high density. Two reference plasmas with type-I ELMs are analysed, one with a deuterium gas puff and one without, in order to provide a reference for the behaviour in type-II ELMy regimes and high density ELM mitigation with external magnetic perturbations at ASDEX Upgrade. For type-II ELMs it is found that while a similar pedestal top pressure is sustained at the higher density, the temperature gradient decreases in the pedestal. This results in lower local and flux surface averaged current densities in these phases, which reduces the drive for the peeling mode. No significant differences between the current density measured in the type-I phase and ELM mitigated phase is seen when external perturbations are applied, though the pedestal top density was increased. Finally, ELMs during the nitrogen seeded phase of a high performance discharge are analysed and compared to ELMs in the reference phase. An increased pedestal pressure gradient, which is the source of confinement improvement in impurity seeded discharges, causes a local current density increase. However, the increased Zeff in the pedestal acts to reduce the flux surface averaged current density. This dichotomy, which is not observed in other mitigation regimes, could act to stabilize both the ballooning mode and the peeling mode at the

  1. Comparison of collisional radiative models for edge electron density reconstruction from Li I (2s-2p) emission profiles

    Energy Technology Data Exchange (ETDEWEB)

    Stoschus, H.; Hudson, B.; Munoz Burgos, J. M. [Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37831-0117 (United States); Thomas, D. M. [General Atomics, San Diego, California 92186-5608 (United States); Schweinzer, J. [Max-Planck-Institut fuer Plasmaphysik, Euratom Association, 85748 Garching (Germany)

    2012-10-15

    Four collisional radiative models (CRMs) for reconstruction of the edge electron density profile from the measured Li I (2s-2p) emission profile of an accelerated lithium beam are compared using experimental data from DIII-D. It is shown for both L- and H-mode plasmas that edge density profiles reconstructed with the CRMs DDD2, ABSOLUT, [Sasaki et al. Rev. Sci. Instrum. 64, 1699 (1993)] and a new model developed at DIII-D agree in a density scan from n{sub e}{sup ped}= (2.0-6.5) Multiplication-Sign 10{sup 19} m{sup -3} within 20%, 20%, <5%, and 40%, respectively, of the pedestal density measured with Thomson scattering. Profile shape and absolute density vary in a scan of the effective ion charge Z{sub eff}= 1-6 up to a factor of two but agree with Thomson data for Z{sub eff}= 1-2 within the error bars.

  2. On the choice of lens density profile in time delay cosmography

    Science.gov (United States)

    Sonnenfeld, Alessandro

    2018-03-01

    Time delay lensing is a mature and competitive cosmological probe. However, it is limited in accuracy by the well-known problem of the mass-sheet degeneracy: too rigid assumptions on the density profile of the lens can potentially bias the inference on cosmological parameters. I investigate the degeneracy between the choice of the lens density profile and the inference on the Hubble constant, focusing on double image systems. By expanding lensing observables in terms of the local derivatives of the lens potential around the Einstein radius, and assuming circular symmetry, I show that 3 degrees of freedom in the radial direction are necessary to achieve a few per cent accuracy in the time-delay distance. Additionally, while the time delay is strongly dependent on the second derivative of the potential, observables typically used to constrain lens models in time-delay studies, such as image position and radial magnification information, are mostly sensitive to the first and third derivatives, making it very challenging to accurately determine time-delay distances with lensing data alone. Tests on mock observations show that the assumption of a power-law density profile results in a 5 per cent average bias on H0, with a 6 per cent scatter. Using a more flexible model and adding unbiased velocity dispersion constraints allows me to obtain an inference with 1 per cent accuracy. A power-law model can still provide 3 per cent accuracy if velocity dispersion measurements are used to constrain its slope. Although this study is based on the assumption of axisymmetry, its main findings can be generalized to cases with moderate ellipticity.

  3. Partial swelling of latex particles by two monomers

    NARCIS (Netherlands)

    Noel, E.F.J.; Maxwell, I.A.; German, A.L.

    1993-01-01

    The swelling of polymeric latex particles with solvent and monomer is of great importance for the emulsion polymn. process in regard to compn. drift and rate of polymn. For the monomer combination, Me acrylate-vinyl acetate, both satn. and partial swelling were detd. exptl. Theories for satn.

  4. Novel analysis technique for measuring edge density fluctuation profiles with reflectometry in the Large Helical Device

    Science.gov (United States)

    Creely, A. J.; Ida, K.; Yoshinuma, M.; Tokuzawa, T.; Tsujimura, T.; Akiyama, T.; Sakamoto, R.; Emoto, M.; Tanaka, K.; Michael, C. A.

    2017-07-01

    A new method for measuring density fluctuation profiles near the edge of plasmas in the Large Helical Device (LHD) has been developed utilizing reflectometry combined with pellet-induced fast density scans. Reflectometer cutoff location was calculated by proportionally scaling the cutoff location calculated with fast far infrared laser interferometer (FIR) density profiles to match the slower time resolution results of the ray-tracing code LHD-GAUSS. Plasma velocity profile peaks generated with this reflectometer mapping were checked against velocity measurements made with charge exchange spectroscopy (CXS) and were found to agree within experimental uncertainty once diagnostic differences were accounted for. Measured density fluctuation profiles were found to peak strongly near the edge of the plasma, as is the case in most tokamaks. These measurements can be used in the future to inform inversion methods of phase contrast imaging (PCI) measurements. This result was confirmed with both a fixed frequency reflectometer and calibrated data from a multi-frequency comb reflectometer, and this method was applied successfully to a series of discharges. The full width at half maximum of the turbulence layer near the edge of the plasma was found to be only 1.5-3 cm on a series of LHD discharges, less than 5% of the normalized minor radius.

  5. Density and impurity profile behaviours in HL-2A tokamak with different gas fuelling methods

    International Nuclear Information System (INIS)

    Zheng-Ying, Cui; Yan, Zhou; Wei, Li; Bei-Bin, Feng; Ping, Sun; Chun-Feng, Dong; Yi, Liu; Wen-Yu, Hong; Qing-Wei, Yang; Xuan-Tong, Ding; Xu-Ru, Duan

    2009-01-01

    The electron density profile peaking and the impurity accumulation in the HL-2A tokamak plasma are observed when three kinds of fuelling methods are separately used at different fuelling particle locations. The density profile becomes more peaked when the line-averaged electron density approaches the Greenwald density limit n G and, consequently, impurity accumulation is often observed. A linear increase regime in the density range n e G and a saturation regime in n e > 0.6n G are obtained. There is no significant difference in achieved density peaking factor f ne between the supersonic molecular beam injection (SMBI) and gas puffing into the plasma main chamber. However, the achieved f ne is relatively low, in particular, in the case of density below 0.7n G , when the working gas is puffed into the divertor chamber. A discharge with a density as high as 1.2n G , i.e. n e = 1.2n G , can be achieved by SMBI just after siliconization as a wall conditioning. The metallic impurities, such as iron and chromium, also increase remarkably when the impurity accumulation happens. The mechanism behind the density peaking and impurity accumulation is studied by investigating both the density peaking factor versus the effective collisionality and the radiation peaking versus density peaking. (fluids, plasmas and electric discharges)

  6. Spectral and Temporal Properties of the Alpha and Beta Subunits and (alpha Beta) Monomer Isolated from Nostoc SP. Using Picosecond Laser Spectroscopy.

    Science.gov (United States)

    Dagen, Aaron J.

    1985-12-01

    The fluorescence decay profiles, relative quantum yield and transmission of the (alpha), (beta) and ((alpha)(beta)) complexes from phycoerythrin isolated from the photosynthetic antenna system of Nostoc sp. and measured by single picosecond laser spectroscopic techniques is studied. The fluorescence decay profiles of all three complexes are found to be intensity independent for the intensity range investigated ((TURN)4 x 10('13) to (TURN)4 x 10('15) photons-cm('-2) per pulse). The apparent decrease in the relative quantum yield of all three complexes as intensity increases is offset by a corresponding increase in the relative transmission. This evidence, along with the intensity independent fluorescence kinetics, suggests that exciton annihilation is absent in these complexes. The decay profiles are fit to models assuming energy transfer amongst fluorescing chromophores. The intraprotein transfer rate is found to be 100 ps in the (alpha) subunit, 666 ps in the (beta) subunit. Constraining these rates to be identical in the monomer results in explaining the monomer kinetics by an increase in the nonradiative rate of the f(,(beta)) chromophore, an apparent result of aggregation effects.

  7. GPCR homomers and heteromers: a better choice as targets for drug development than GPCR monomers?

    Science.gov (United States)

    Casadó, Vicent; Cortés, Antoni; Mallol, Josefa; Pérez-Capote, Kamil; Ferré, Sergi; Lluis, Carmen; Franco, Rafael; Canela, Enric I

    2009-11-01

    G protein-coupled receptors (GPCR) are targeted by many therapeutic drugs marketed to fight against a variety of diseases. Selection of novel lead compounds are based on pharmacological parameters obtained assuming that GPCR are monomers. However, many GPCR are expressed as dimers/oligomers. Therefore, drug development may consider GPCR as homo- and hetero-oligomers. A two-state dimer receptor model is now available to understand GPCR operation and to interpret data obtained from drugs interacting with dimers, and even from mixtures of monomers and dimers. Heteromers are distinct entities and therefore a given drug is expected to have different affinities and different efficacies depending on the heteromer. All these concepts would lead to broaden the therapeutic potential of drugs targeting GPCRs, including receptor heteromer-selective drugs with a lower incidence of side effects, or to identify novel pharmacological profiles using cell models expressing receptor heteromers.

  8. Midplane neutral density profiles in the National Spherical Torus Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Stotler, D. P., E-mail: dstotler@pppl.gov; Bell, R. E.; Diallo, A.; LeBlanc, B. P.; Podestà, M.; Roquemore, A. L.; Ross, P. W. [Princeton Plasma Physics Laboratory, Princeton University, P. O. Box 451, Princeton, New Jersey 08543-0451 (United States); Scotti, F. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

    2015-08-15

    Atomic and molecular density data in the outer midplane of NSTX [Ono et al., Nucl. Fusion 40, 557 (2000)] are inferred from tangential camera data via a forward modeling procedure using the DEGAS 2 Monte Carlo neutral transport code. The observed Balmer-β light emission data from 17 shots during the 2010 NSTX campaign display no obvious trends with discharge parameters such as the divertor Balmer-α emission level or edge deuterium ion density. Simulations of 12 time slices in 7 of these discharges produce molecular densities near the vacuum vessel wall of 2–8 × 10{sup 17 }m{sup −3} and atomic densities ranging from 1 to 7 × 10{sup 16 }m{sup −3}; neither has a clear correlation with other parameters. Validation of the technique, begun in an earlier publication, is continued with an assessment of the sensitivity of the simulated camera image and neutral densities to uncertainties in the data input to the model. The simulated camera image is sensitive to the plasma profiles and virtually nothing else. The neutral densities at the vessel wall depend most strongly on the spatial distribution of the source; simulations with a localized neutral source yield densities within a factor of two of the baseline, uniform source, case. The uncertainties in the neutral densities associated with other model inputs and assumptions are ≤50%.

  9. Magnetically filtered Faraday probe for measuring the ion current density profile of a Hall thruster

    International Nuclear Information System (INIS)

    Rovey, Joshua L.; Walker, Mitchell L.R.; Gallimore, Alec D.; Peterson, Peter Y.

    2006-01-01

    The ability of a magnetically filtered Faraday probe (MFFP) to obtain the ion current density profile of a Hall thruster is investigated. The MFFP is designed to eliminate the collection of low-energy, charge-exchange (CEX) ions by using a variable magnetic field as an ion filter. In this study, a MFFP, Faraday probe with a reduced acceptance angle (BFP), and nude Faraday probe are used to measure the ion current density profile of a 5 kW Hall thruster operating over the range of 300-500 V and 5-10 mg/s. The probes are evaluated on a xenon propellant Hall thruster in the University of Michigan Large Vacuum Test Facility at operating pressures within the range of 4.4x10 -4 Pa Xe (3.3x10 -6 Torr Xe) to 1.1x10 -3 Pa Xe (8.4x10 -6 Torr Xe) in order to study the ability of the Faraday probe designs to filter out CEX ions. Detailed examination of the results shows that the nude probe measures a greater ion current density profile than both the MFFP and BFP over the range of angular positions investigated for each operating condition. The differences between the current density profiles obtained by each probe are attributed to the ion filtering systems employed. Analysis of the results shows that the MFFP, operating at a +5 A solenoid current, provides the best agreement with flight-test data and across operating pressures

  10. Kinetic theory of neutrals in a bounded plasma slab with inhomogeneous temperature and density profile

    International Nuclear Information System (INIS)

    Tendler, M.B.; Agren, O.

    1982-01-01

    The transport of neutral hydrogen atoms in a hydrogen plasma slab is considered. The influence of the inhomogeneous ion temperature profile on the neutral density and distribution is discussed as well as the influence of the neutral edge energy, charge exchange, and ionization rates. The analytical solutions for the neutral density and distribution function are obtained and compared with the numerical results. The effects due to the inhomogeneous temperature profile are discussed. The recommen-dations from the viewpoint of the effects mentioned previously for the purposes of the cold-gas mantle system have been given

  11. Affinity proteomic profiling of plasma for proteins associated to area-based mammographic breast density.

    Science.gov (United States)

    Byström, Sanna; Eklund, Martin; Hong, Mun-Gwan; Fredolini, Claudia; Eriksson, Mikael; Czene, Kamila; Hall, Per; Schwenk, Jochen M; Gabrielson, Marike

    2018-02-14

    Mammographic breast density is one of the strongest risk factors for breast cancer, but molecular understanding of how breast density relates to cancer risk is less complete. Studies of proteins in blood plasma, possibly associated with mammographic density, are well-suited as these allow large-scale analyses and might shed light on the association between breast cancer and breast density. Plasma samples from 1329 women in the Swedish KARMA project, without prior history of breast cancer, were profiled with antibody suspension bead array (SBA) assays. Two sample sets comprising 729 and 600 women were screened by two different SBAs targeting a total number of 357 proteins. Protein targets were selected through searching the literature, for either being related to breast cancer or for being linked to the extracellular matrix. Association between proteins and absolute area-based breast density (AD) was assessed by quantile regression, adjusting for age and body mass index (BMI). Plasma profiling revealed linear association between 20 proteins and AD, concordant in the two sets of samples (p density and processes of tissue homeostasis, DNA repair, cancer development and/or progression in breast cancer. Further validation and follow-up studies of the shortlisted protein candidates in independent cohorts will be needed to infer their role in breast density and its progression in premenopausal and postmenopausal women.

  12. Analytical solution for the mode conversion equations with steep exponential density profiles

    International Nuclear Information System (INIS)

    Alava, M.J.; Heikkinen, J.A.

    1992-01-01

    A general analytical solution for the converted power from the fast magnetosonic wave to an ion Bernstein wave in a magnetized plasma with an exponential steeply increasing density profile is given in the closed form. The solution covers both the conversion at the lower-hybrid resonance and the conversion through the density gradient for small parallel wave numbers. As an application, the conversion coefficients at the scrape-off layer plasma are estimated in the context of ion cyclotron heating of a tokamak plasma

  13. Density profile of dark matter haloes and galaxies in the HORIZON-AGN simulation: the impact of AGN feedback

    Science.gov (United States)

    Peirani, Sébastien; Dubois, Yohan; Volonteri, Marta; Devriendt, Julien; Bundy, Kevin; Silk, Joe; Pichon, Christophe; Kaviraj, Sugata; Gavazzi, Raphaël; Habouzit, Mélanie

    2017-12-01

    Using a suite of three large cosmological hydrodynamical simulations, HORIZON-AGN, HORIZON–NOAGN (no AGN feedback) and HORIZON-DM (no baryons), we investigate how a typical sub-grid model for AGN feedback affects the evolution of the inner density profiles of massive dark matter haloes and galaxies. Based on direct object-to-object comparisons, we find that the integrated inner mass and density slope differences between objects formed in these three simulations (hereafter, HAGN, HnoAGN and HDM) significantly evolve with time. More specifically, at high redshift (z ∼ 5), the mean central density profiles of HAGN and HnoAGN dark matter haloes tend to be much steeper than their HDM counterparts owing to the rapidly growing baryonic component and ensuing adiabatic contraction. By z ∼ 1.5, these mean halo density profiles in HAGN have flattened, pummelled by powerful AGN activity ('quasar mode'): the integrated inner mass difference gaps with HnoAGN haloes have widened, and those with HDM haloes have narrowed. Fast forward 9.5 billion years, down to z = 0, and the trend reverses: HAGN halo mean density profiles drift back to a more cusped shape as AGN feedback efficiency dwindles ('radio mode'), and the gaps in integrated central mass difference with HnoAGN and HDM close and broaden, respectively. On the galaxy side, the story differs noticeably. Averaged stellar profile central densities and inner slopes are monotonically reduced by AGN activity as a function of cosmic time, resulting in better agreement with local observations.

  14. Radiation-initiated emulsion copolymerization of styrene and carboxylic acid monomers

    International Nuclear Information System (INIS)

    Egusa, S.; Makuuchi, K.

    1982-01-01

    The emulsion copolymerization of styrene and carboxylic acid monomers such as acrylic, methacrylic, and itaconic acids (AAc, MAAc, IAc) was studied by using 60 Co γ-rays as initiator and sodium dodecylsulfate as emulsifier. The polymerization behavior of these acid monomers was followed by simultaneous conductometric and potentiometric titrations for a latex sample taken in polymerization. The polymerization rate of these acid monomers increases in the following order of hydrophobicity: IAc < AAc < MAAc; this suggests that their polymerization sites are mainly the surface and/or subsurface regions of latex particles. The copolymerization rate of styrene and acid monomer increases with an increase in the acid monomer content for AAc and MAAc, whereas for IAc the rate decreases. The particle sizes determined by the stopped-flow method reveal that this variation of copolymerization rate cannot be explained by the number of growing particles and should be attributed to another factor; for instance, the transfer rate of styrene molecules from oil droplets to growing particles

  15. Mangrove tannins and their flavanoid monomers as alternative steel corrosion inhibitors in acidic medium

    Energy Technology Data Exchange (ETDEWEB)

    Rahim, Afidah A. [School of Chemical Sciences, University Sains Malaysia, 11800 Penang (Malaysia)]. E-mail: afidah@usm.my; Rocca, E. [Laboratoire de Chimie du Solide Mineral, Universite Henri Poincare, Nancy I BP 239, 54506 Vandoeuvre Les Nancy (France); Steinmetz, J. [Laboratoire de Chimie du Solide Mineral, Universite Henri Poincare, Nancy I BP 239, 54506 Vandoeuvre Les Nancy (France); Kassim, M.J. [School of Chemical Sciences, University Sains Malaysia, 11800 Penang (Malaysia); Adnan, R. [School of Chemical Sciences, University Sains Malaysia, 11800 Penang (Malaysia); Sani Ibrahim, M. [School of Chemical Sciences, University Sains Malaysia, 11800 Penang (Malaysia)

    2007-02-15

    The inhibitive behaviour on steel of flavanoid monomers that constitute mangrove tannins namely catechin, epicatechin, epigallocatechin and epicatechingallate was investigated in an aerated HCl solution via electrochemical methods. The monomers were found to be mainly cathodic inhibitors and the inhibition efficiency was dependent on concentration. To explain the adsorptive behaviour of the molecules on the steel surface, a semiempirical approach involving quantum chemical calculations using HyperChem 6.0 was undertaken. The HOMO electronic density of the molecule was used to explain the inhibiting mechanism. The most probable adsorption centers were found in the vicinity of the phenolic groups. In a second part, the use of mangrove tannin, extracted from the mangrove barks as steel corrosion inhibitors in acidic media was investigated and its inhibitive efficiency was compared with that of commercial mimosa, quebracho and chestnut tannins. The inhibitive performance of mangrove tannins was comparable to the other tannins investigated, indicating their potential in corrosion protection.

  16. Mangrove tannins and their flavanoid monomers as alternative steel corrosion inhibitors in acidic medium

    International Nuclear Information System (INIS)

    Rahim, Afidah A.; Rocca, E.; Steinmetz, J.; Kassim, M.J.; Adnan, R.; Sani Ibrahim, M.

    2007-01-01

    The inhibitive behaviour on steel of flavanoid monomers that constitute mangrove tannins namely catechin, epicatechin, epigallocatechin and epicatechingallate was investigated in an aerated HCl solution via electrochemical methods. The monomers were found to be mainly cathodic inhibitors and the inhibition efficiency was dependent on concentration. To explain the adsorptive behaviour of the molecules on the steel surface, a semiempirical approach involving quantum chemical calculations using HyperChem 6.0 was undertaken. The HOMO electronic density of the molecule was used to explain the inhibiting mechanism. The most probable adsorption centers were found in the vicinity of the phenolic groups. In a second part, the use of mangrove tannin, extracted from the mangrove barks as steel corrosion inhibitors in acidic media was investigated and its inhibitive efficiency was compared with that of commercial mimosa, quebracho and chestnut tannins. The inhibitive performance of mangrove tannins was comparable to the other tannins investigated, indicating their potential in corrosion protection

  17. Simulation study ε-Caprolactam monomer and metallic elements migration from irradiated polymeric packaging into food stimulants

    International Nuclear Information System (INIS)

    Rosa, Faena Machado Leite

    2008-01-01

    For decades migration study of chemical compounds from packaging into food, such as metals, residual monomers and additives, is a very important issue, concerning public health and minimize chemical contamination. In this work, it was done irradiations of packagings taken in contact with food simulant, and it was studied this migration through a mathematical model of the diffusion process, compiled in a computational simulation method in order to study the microscopic behavior of migration of metallic elements cadmium, chromium, antimony and cobalt, present in metallic plastics from dairy product packagings, and also the migration of - caprolactam monomer, present in nylon polymeric plastics used for package meat stuffs, to the food simulant acetic acid 3%. The results from simulations of the migration of -caprolactam monomer were compared with experimental results obtained from high resolution gas chromatography (HRGC) measurements, and the simulation of metallic elements migration were compared with the neutron activation analysis measurements (NAA). These experimental results were performed and kindly informed by another research groups, partners in this project. The food packaging system was discretized in one-dimension space and in time and the partial differential equation that defines the diffusive process, the second 'Fick's law', together with an equation of Arrhenius type dealing with the thermal influence, were solved using finite differences. The final step of the resolution was a tridiagonal linear system, solved using the Thomas algorithm. It was studied, and in some cases even foreseen, experimental quantities, like the diffusion coefficient, activation energy and concentration profile of migrant compounds, allowing the understanding of the diffusion process and the quantitative estimate of the migration of such compounds under ionizing radiation influence. Variation on the initial concentration levels (C 0 ) of the monomer inside the packaging

  18. Line profiles of hydrogenic ions from high-temperature and high-density plasmas

    International Nuclear Information System (INIS)

    Hou Qing; Li Jianming

    1991-01-01

    Applying the Hooper's first-order theory, the authors calculate the static micro-electric field distributions in plasmas containing various multiply-charged ions. The influences of the impurity concentrations on the micro electric field distributions and on the Lyman profiles (n→1) from hydrogenic ions are analysed. Based on the optical-thin line profiles, the radiation transfer equation in sphere plasmas with various optical depths is solved. The results confirm that the opacity-broadening of the line profiles has almost no effect on the separation of Lyman β splitted peaks. Such separation is determined by electric field at which the static micro-electric field distribution has a maximum. The separation can be utilized for spatially resolved and temporally resolved density diagnostic of fusion plasmas

  19. Determination of CT number and density profile of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using computed tomography imaging and electron density phantom

    Energy Technology Data Exchange (ETDEWEB)

    Yusof, Mohd Fahmi Mohd, E-mail: mfahmi@usm.my; Hamid, Puteri Nor Khatijah Abdul; Tajuddin, Abdul Aziz [School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Bauk, Sabar [School of Distance Education, Universiti Sains Malaysia, 11800 Penang (Malaysia); Hashim, Rokiah [School of Industrial Technologies, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2015-04-29

    Plug density phantoms were constructed in accordance to CT density phantom model 062M CIRS using binderless, pre-treated and tannin-based Rhizophora Spp. particleboards. The Rhizophora Spp. plug phantoms were scanned along with the CT density phantom using Siemens Somatom Definition AS CT scanner at three CT energies of 80, 120 and 140 kVp. 15 slices of images with 1.0 mm thickness each were taken from the central axis of CT density phantom for CT number and CT density profile analysis. The values were compared to water substitute plug phantom from the CT density phantom. The tannin-based Rhizophora Spp. gave the nearest value of CT number to water substitute at 80 and 120 kVp CT energies with χ{sup 2} value of 0.011 and 0.014 respectively while the binderless Rhizphora Spp. gave the nearest CT number to water substitute at 140 kVp CT energy with χ{sup 2} value of 0.023. The tannin-based Rhizophora Spp. gave the nearest CT density profile to water substitute at all CT energies. This study indicated the suitability of Rhizophora Spp. particleboard as phantom material for the use in CT imaging studies.

  20. Determination of CT number and density profile of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using computed tomography imaging and electron density phantom

    International Nuclear Information System (INIS)

    Yusof, Mohd Fahmi Mohd; Hamid, Puteri Nor Khatijah Abdul; Tajuddin, Abdul Aziz; Bauk, Sabar; Hashim, Rokiah

    2015-01-01

    Plug density phantoms were constructed in accordance to CT density phantom model 062M CIRS using binderless, pre-treated and tannin-based Rhizophora Spp. particleboards. The Rhizophora Spp. plug phantoms were scanned along with the CT density phantom using Siemens Somatom Definition AS CT scanner at three CT energies of 80, 120 and 140 kVp. 15 slices of images with 1.0 mm thickness each were taken from the central axis of CT density phantom for CT number and CT density profile analysis. The values were compared to water substitute plug phantom from the CT density phantom. The tannin-based Rhizophora Spp. gave the nearest value of CT number to water substitute at 80 and 120 kVp CT energies with χ 2 value of 0.011 and 0.014 respectively while the binderless Rhizphora Spp. gave the nearest CT number to water substitute at 140 kVp CT energy with χ 2 value of 0.023. The tannin-based Rhizophora Spp. gave the nearest CT density profile to water substitute at all CT energies. This study indicated the suitability of Rhizophora Spp. particleboard as phantom material for the use in CT imaging studies

  1. In situ polymerization of vinyl monomers in polyester yarns

    International Nuclear Information System (INIS)

    Avny, Y.; Rebenfeld, L.; Weigmann, H.D.

    1978-01-01

    The effects of a pretreatment of polyester (PET) yarns with a strongly interacting solvent such as dimethylformamide (DMF) on vinyl monomer incorporation were investigated. When the DMF pretreatment is carried out at high temperatures (above 120 0 C), the swollen PET structure is stabilized by solvent-induced secondary crystallization. This substrate is highly suitable for the incorporation of vinyl monomers. In situ polymerization of vinyl monomers in DMF-treated PET was investigated using chemical and γ-irradiation polymerization techniques, both in the presence and in the absence of excess monomer outside the PET fibers. When polymerization was carried out in a system in which a constant supply of free radicals was available from the outside of the PET fibers, lower initiator concentrations and smaller γ-irradiation doses were necessary. These results are attributed to a low efficiency of the initiator inside the PET fiber due to mobility restrictions. Water uptake and moisture regain of PET yarns containing poly(hydroxyethyl methacrylate) and poly(acrylic acid) were also investigated. When most of the vinyl polymer was inside the PET fiber, water absorption was limited. The changes in mechanical properties of the PET yarns resulting from the DMF pretreatment were partially reversed by in situ polymerization of vinyl monomers

  2. Base-catalyzed depolymerization of lignin : separation of monomers

    Energy Technology Data Exchange (ETDEWEB)

    Vigneault, A. [Sherbrooke Univ., PQ (Canada). Dept. of Chemical Engineering; Johnson, D.K. [National Renewable Energy Laboratory, Golden, CO (United States); Chornet, E. [Sherbrooke Univ., PQ (Canada). Dept. of Chemical Engineering; National Renewable Energy Laboratory, Golden, CO (United States)

    2007-12-15

    Biofuels produced from residual lignocellulosic biomass range from ethanol to biodiesel. The use of lignin for the production of alternate biofuels and green chemicals has been studied with particular emphasis on the structure of lignin and its oxyaromatic nature. In an effort to fractionate lignocellulosic biomass and valorize specific constitutive fractions, the authors developed a strategy for the separation of 12 added value monomers produced during the hydrolytic base catalyzed depolymerization (BCD) of a Steam Exploded Aspen Lignin. The separation strategy was similar to vanillin purification to obtain pure monomers, but combining more steps after the lignin depolymerization such as acidification, batch liquid-liquid-extraction (LLE), followed by vacuum distillation, liquid chromatography (LC) and crystallization. The purpose was to develop basic data for an industrial size process flow diagram, and to evaluate both the monomer losses during the separation and the energy requirements. Experimentally testing of LLE, vacuum distillation and flash LC in the laboratory showed that batch vacuum distillation produced up to 4 fractions. Process simulation revealed that a series of 4 vacuum distillation columns could produce 5 distinct monomer streams, of which 3 require further chromatography and crystallization operations for purification. 22 refs., 4 tabs., 8 figs.

  3. Studies on curing effect of phosphite monomer by EB radiation in the air

    International Nuclear Information System (INIS)

    Xiao, B.; Zhou, Y.; Li, S.; Luo, M.; Wang, X.; Zhao, P.

    2000-01-01

    A new type phosphite active monomer was synthesized. The resisting oxygen inhibition effect of this monomer and the effects of irradiation dose and concentration of phosphite active monomer on curing were studied. At the same time, curing results were analysed, through gel content and IR spectrum. The excellent resisting oxygen inhibition result of this phosphite active monomer was shown by experiments. EB radiation curing in the air was successfully carried out by the phosphite active monomer. (author)

  4. Fitting of the Thomson scattering density and temperature profiles on the COMPASS tokamak

    International Nuclear Information System (INIS)

    Stefanikova, E.; Peterka, M.; Bohm, P.; Bilkova, P.; Aftanas, M.; Urban, J.; Hron, M.; Panek, R.; Sos, M.

    2016-01-01

    A new technique for fitting the full radial profiles of electron density and temperature obtained by the Thomson scattering diagnostic in H-mode discharges on the COMPASS tokamak is described. The technique combines the conventionally used modified hyperbolic tangent function for the edge transport barrier (pedestal) fitting and a modification of a Gaussian function for fitting the core plasma. Low number of parameters of this combined function and their straightforward interpretability and controllability provide a robust method for obtaining physically reasonable profile fits. Deconvolution with the diagnostic instrument function is applied on the profile fit, taking into account the dependence on the actual magnetic configuration.

  5. Fitting of the Thomson scattering density and temperature profiles on the COMPASS tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Stefanikova, E. [Institute of Plasma Physics of the CAS, Za Slovankou 1782/3, 180 00 Prague (Czech Republic); Division of Fusion Plasma Physics, KTH Royal Institute of Technology, SE-10691 Stockholm (Sweden); Peterka, M. [Institute of Plasma Physics of the CAS, Za Slovankou 1782/3, 180 00 Prague (Czech Republic); MFF Charles University, V Holešovičkách 2, 180 00 Prague 8 (Czech Republic); Bohm, P., E-mail: bohm@ipp.cas.cz; Bilkova, P.; Aftanas, M.; Urban, J.; Hron, M.; Panek, R. [Institute of Plasma Physics of the CAS, Za Slovankou 1782/3, 180 00 Prague (Czech Republic); Sos, M. [Institute of Plasma Physics of the CAS, Za Slovankou 1782/3, 180 00 Prague (Czech Republic); Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Břehová 7, 115 19 Prague 1 (Czech Republic)

    2016-11-15

    A new technique for fitting the full radial profiles of electron density and temperature obtained by the Thomson scattering diagnostic in H-mode discharges on the COMPASS tokamak is described. The technique combines the conventionally used modified hyperbolic tangent function for the edge transport barrier (pedestal) fitting and a modification of a Gaussian function for fitting the core plasma. Low number of parameters of this combined function and their straightforward interpretability and controllability provide a robust method for obtaining physically reasonable profile fits. Deconvolution with the diagnostic instrument function is applied on the profile fit, taking into account the dependence on the actual magnetic configuration.

  6. Role of ion magnetization in formation of radial density profile in magnetically expanding plasma produced by helicon antenna

    Science.gov (United States)

    Yadav, Sonu; Ghosh, Soumen; Bose, Sayak; Barada, Kshitish K.; Pal, Rabindranath; Chattopadhyay, Prabal K.

    2018-04-01

    Experimentally, the density profile in the magnetic nozzle of a helicon antenna based plasma device is seen to be modified from being centrally peaked to that of hollow nature as the external magnetic field is increased. It occurs above a characteristic field value when the ions become magnetized in the expansion chamber. The density profile in the source chamber behind the nozzle, however, remains peaked on-axis irrespective of the magnetic field. The electron temperature there is observed to be hollow and this nature is carried to the expansion chamber along the field line. In the electron energy distribution near the off axis peak location, a high energy tail exists. Rotation of these tail electrons in the azimuthal direction due to the gradient-B drift in the expansion chamber leads to an additional off-axis ionization and forms the hollow density profile. It seems that if the ions are not magnetized, then the off-axially produced additional plasma is not confined and the density profile retains the on-axis peak nature. The present experiment successfully demonstrates how the knowledge of the ion magnetization together with tail electrons significantly contributes to the design of an efficient helicon plasma based thruster.

  7. Advanced density profile reflectometry; the state-of-the-art and measurement prospects for ITER

    Science.gov (United States)

    Doyle, E. J.

    2006-10-01

    Dramatic progress in millimeter-wave technology has allowed the realization of a key goal for ITER diagnostics, the routine measurement of the plasma density profile from millimeter-wave radar (reflectometry) measurements. In reflectometry, the measured round-trip group delay of a probe beam reflected from a plasma cutoff is used to infer the density distribution in the plasma. Reflectometer systems implemented by UCLA on a number of devices employ frequency-modulated continuous-wave (FM-CW), ultrawide-bandwidth, high-resolution radar systems. One such system on DIII-D has routinely demonstrated measurements of the density profile over a range of electron density of 0-6.4x10^19,m-3, with ˜25 μs time and ˜4 mm radial resolution, meeting key ITER requirements. This progress in performance was made possible by multiple advances in the areas of millimeter-wave technology, novel measurement techniques, and improved understanding, including: (i) fast sweep, solid-state, wide bandwidth sources and power amplifiers, (ii) dual polarization measurements to expand the density range, (iii) adaptive radar-based data analysis with parallel processing on a Unix cluster, (iv) high memory depth data acquisition, and (v) advances in full wave code modeling. The benefits of advanced system performance will be illustrated using measurements from a wide range of phenomena, including ELM and fast-ion driven mode dynamics, L-H transition studies and plasma-wall interaction. The measurement capabilities demonstrated by these systems provide a design basis for the development of the main ITER profile reflectometer system. This talk will explore the extent to which these reflectometer system designs, results and experience can be translated to ITER, and will identify what new studies and experimental tests are essential.

  8. Measuring Density Profiles of Electrons and Heavy Particles in a Stable Axially Blown Arc

    Science.gov (United States)

    Carstensen, J.; Stoller, P.; Galletti, B.; Doiron, C. B.; Sokolov, A.

    2017-08-01

    Two-color spatial carrier wave interferometry employing pulsed 532- and 671-nm lasers is used to measure the electron-density and heavy-particle-density profiles in the stagnation point of a stable, axially blown arc in argon for currents of 50 to 200 A and stagnation point pressures of 0.2 to 16 bar. This technique takes advantage of the fact that the free-electron contribution to the refractive index depends strongly on the wavelength, while that of the heavy particles does not. The high spatial resolution achieved allows the hot core of the arc to be readily distinguished from the surrounding boundary layer. A custom-built test device is used to ensure flow conditions that lead to a stable, axisymmetric arc; this permits the reconstruction of the density and temperature profiles using a single projection (interferometric image) of the refractive-index distribution through the arc (at two wavelengths). The arc radius determined from the heavy-particle density decreases with increasing stagnation pressure and increases with the current. These measurements are in good agreement with a simple axially blown arc model taking into account Ohmic heating, radiation losses, and enthalpy flow for core temperatures of approximately 16 500 K. The measured electron density at the center of the arc agrees well with a prediction based on local thermodynamic equilibrium.

  9. Note: Interpolation for evaluation of a two-dimensional spatial profile of plasma densities at low gas pressures

    International Nuclear Information System (INIS)

    Oh, Se-Jin; Kim, Young-Chul; Chung, Chin-Wook

    2011-01-01

    An interpolation algorithm for the evaluation of the spatial profile of plasma densities in a cylindrical reactor was developed for low gas pressures. The algorithm is based on a collisionless two-dimensional fluid model. Contrary to the collisional case, i.e., diffusion fluid model, the fitting algorithm depends on the aspect ratio of the cylindrical reactor. The spatial density profile of the collisionless fitting algorithm is presented in two-dimensional images and compared with the results of the diffusion fluid model.

  10. Analysis of plasma equilibrium based on orbit-driven current density profile in steady-state plasma on QUEST

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, K., E-mail: nakamura@triam.kyushu-u.ac.jp [RIAM, Kyushu University, Kasuga 816-8580 (Japan); Alam, M.M. [IGSES, Kyushu University, Kasuga 816-8580 (Japan); Jiang, Y.Z. [Tsinghua University, Beijing 100084 (China); Mitarai, O. [Tokai University, Kumamoto 862-8652 (Japan); Kurihara, K.; Kawamata, Y.; Sueoka, M.; Takechi, M. [Japan Atomic Energy Agency, Naka 311-0193 (Japan); Hasegawa, M.; Tokunaga, K.; Araki, K.; Zushi, H.; Hanada, K.; Fujisawa, A.; Idei, H.; Nagashima, Y.; Kawasaki, S.; Nakashima, H.; Higashijima, A.; Nagata, T. [RIAM, Kyushu University, Kasuga 816-8580 (Japan); and others

    2016-11-01

    Highlights: • High energy particle guiding center orbit is calculated as a contour plot of conserved variable. • Current density profile is analyzed based on the orbit-driven current. • Plasma equilibrium is reconstructed by considering the hollow current profile. - Abstract: In the present RF-driven (ECCD) steady-state plasma on QUEST (B{sub t} = 0.25 T, R = 0.68 m, a = 0.40 m), plasma current seems to flow in the open magnetic surface outside of the closed magnetic surface in the low-field region according to plasma current fitting (PCF) method. We consider that the current in the open magnetic surface is due to orbit-driven current by high-energy particles in RF-driven plasma. So based on the analysis of current density profile based on the orbit-driven current, plasma equilibrium is to be calculated. We calculated high energy particles guiding center orbits as a contour plot of conserved variable in Hamiltonian formulation and considered particles initial position with different levels of energy and pitch angles that satisfy resonance condition. Then the profile of orbit-driven current is estimated by multiplying the particle density on the resonance surface and the velocity on the orbits. This analysis shows negative current near the magnetic axis and hollow current profile is expected even if pressure driven current is considered. Considering the hollow current profile shifted toward the low-field region, the equilibrium is fitted by J-EFIT coded by MATLAB.

  11. In situ polymerization of monomers for polyphenylquinoxaline-graphite fiber composites

    Science.gov (United States)

    Serafini, T. T.; Delvigs, P.; Vannucci, R. D.

    1974-01-01

    In situ polymerization of monomers was used to prepare graphite-fiber-reinforced polyphenylquinoxaline composites. Six different monomer combinations were investigated. Composite mechanical property retention characteristics were determined at 316 C (600 F) over an extended time period.

  12. Ion acceleration in electrostatic collisionless shock: on the optimal density profile for quasi-monoenergetic beams

    Science.gov (United States)

    Boella, E.; Fiúza, F.; Stockem Novo, A.; Fonseca, R.; Silva, L. O.

    2018-03-01

    A numerical study on ion acceleration in electrostatic shock waves is presented, with the aim of determining the best plasma configuration to achieve quasi-monoenergetic ion beams in laser-driven systems. It was recently shown that tailored near-critical density plasmas characterized by a long-scale decreasing rear density profile lead to beams with low energy spread (Fiúza et al 2012 Phys. Rev. Lett. 109 215001). In this work, a detailed parameter scan investigating different plasma scale lengths is carried out. As result, the optimal plasma spatial scale length that allows for minimizing the energy spread while ensuring a significant reflection of ions by the shock is identified. Furthermore, a new configuration where the required profile has been obtained by coupling micro layers of different densities is proposed. Results show that this new engineered approach is a valid alternative, guaranteeing a low energy spread with a higher level of controllability.

  13. Kinetics of the monomer-dimer reaction of yeast hexokinase PI.

    Science.gov (United States)

    Hoggett, J G; Kellett, G L

    1992-10-15

    Kinetic studies of the glucose-dependent monomer-dimer reaction of yeast hexokinase PI at pH 8.0 in the presence of 0.1 M-KCl have been carried out using the fluorescence temperature-jump technique. A slow-relaxation effect was observed which was attributed from its dependence on enzyme concentration to the monomer-dimer reaction; the reciprocal relaxation times tau-1 varied from 3 s-1 at low concentrations of glucose to 42 s-1 at saturating concentrations. Rate constants for association (kass.) and dissociation (kdiss.) were determined as a function of glucose concentration using values of the equilibrium association constant of the monomer-dimer reaction derived from sedimentation ultracentrifugation studies under similar conditions, and also from the dependence of tau-2 on enzyme concentration. kass. was almost independent of glucose concentration and its value (2 x 10(5) M-1.s-1) was close to that expected for a diffusion-controlled process. The influence of glucose on the monomer-dimer reaction is entirely due to effects on kdiss., which increases from 0.21 s-1 in the absence of glucose to 25 s-1 at saturating concentrations. The monomer and dimer forms of hexokinase have different affinities and Km values for glucose, and the results reported here imply that there may be a significant lag in the response of the monomer-dimer reaction to changes in glucose concentrations in vivo with consequent hysteretic effects on the hexokinase activity.

  14. Data description and quality assessment of ionospheric electron density profiles for ARPA modeling project. Technical report

    International Nuclear Information System (INIS)

    Conkright, R.O.

    1977-03-01

    This report presents a description of the automated method used to produce electron density (N(h)) profiles from ionograms recorded on 35mm film and an assessment of the resulting data base. A large data base of about 30,000 profiles was required for an ionospheric modeling project. This motivated a search for an automated method of producing profiles. The automated method used is fully described, the resulting data are given a quality grade, and the noon and midnight profiles are presented. Selected portions of this data base are compared with profiles produced by the standard profiling method in use by the Environmental Data Service at Boulder, Colorado

  15. Edge electron density profiles and fluctuations measured by two-dimensional beam emission spectroscopy in the KSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Y. U., E-mail: yunam@nfri.re.kr; Wi, H. M. [National Fusion Research Institute, Daejeon (Korea, Republic of); Zoletnik, S.; Lampert, M. [Wigner RCP Institute for Particle and Nuclear Physics, Budapest (Hungary); Kovácsik, Ákos [Institute of Nuclear Techniques, Budapest Technical University, Budapest (Hungary)

    2014-11-15

    Beam emission spectroscopy (BES) system in Korea Superconducting Tokamak Advanced Research (KSTAR) has recently been upgraded. The background intensity was reduced from 30% to 2% by suppressing the stray lights. This allows acquisition of the relative electron density profiles on the plasma edge without background subtraction from the beam power modulation signals. The KSTAR BES system has its spatial resolution of 1 cm, the temporal resolution of 2 MHz, and a total 32 channel (8 radial × 4 poloidal) avalanche photo diode array. Most measurements were done on the plasma edge, r/a ∼ 0.9, with 8 cm radial measurement width that covers the pedestal range. High speed density profile measurements reveal temporal behaviors of fast transient events, such as the precursors of edge localized modes and the transitions between confinement modes. Low background level also allows analysis of the edge density fluctuation patterns with reduced background fluctuations. Propagation of the density structures can be investigated by comparing the phase delays between the spatially distributed channels.

  16. The LOMOsup(R) process: a solution for residual monomers

    International Nuclear Information System (INIS)

    Derbyshire, R.L.

    1979-01-01

    Regulatory activity over the last several years has addressed the potential problems associated with the migration of residual monomers from a number of commodity food packages. Regardless of the outcome of current debates, it will always be desirable to reduce monomer levels to as low a level as economically practicable so that they do not become indirect additives. The LOMO process is a body of technology inclusive of an ionizing radiation treatment which can result in sharp reduction of residual monomer levels in commodity plastic resins. The process may be applicable to factory intermediates, raw resins, or finished articles. Depending upon the individual system and its monomers, LOMO treatment can result in reductions to levels which press today's analytical test capability. Industrial radiation processing is normally accomplished with electron beam accelerators. Electron beam processing continues to gain in understanding and acceptance as one of the very few basic methods by which energy can be imparted to an industrial process system. Typically, whole factories are constructed around one accelerator. (author)

  17. Measurements of edge density profile modifications during IBW on TFTR

    International Nuclear Information System (INIS)

    Hanson, G.R.; Bush, C.E.; Wilgen, J.B.

    1997-01-01

    Ion Bernstein wave (IBW) antennas are known to have substantial localized effects on the plasma edge. To allow better understanding and measurement of these effects, the TFTR edge reflectometer has been relocated to the new IBW antenna. This move was facilitated by the incorporation of a diagnostic access tube in the IBW antenna identical to the original diagnostic tube in the fast-wave (FW) antenna. This allowed the reflectometer launcher to simply be moved from the old FW antenna to the new IBW antenna. Only a moderate extension of the waveguide transmission line was required to reconnect the reflectometer to the launcher in its new location. Edge density profile modification during IBW experiments has been observed. Results from IBW experiments will be presented and contrasted to the edge density modifications previously observed during FW heating experiments

  18. The effect of the polymerization initiator and light source on the elution of residual Bis-GMA and TEGDMA monomers: A study using liquid chromatography with UV detection.

    Science.gov (United States)

    Denis, Aline B; Diagone, Cristina A; Plepis, Ana M G; Viana, Rommel B

    2015-12-05

    A method for the extraction and quantification of two residual monomers, bisphenol glycidyl dimethacrylate (Bis-GMA) and triethylene glycol dimethacrylate (TEGDMA), that were evaluated using high efficiency liquid chromatography with UV detection was developed and validated in this study. Three types of solvents were applied in the extraction of the monomers (methanol, ethanol and acetonitrile), where the highest extraction efficiency was obtained using acetonitrile. The different resins were prepared by photoactivation of Bis-GMA and TEGDMA monomers. Additionally, the effects of the addition of two photoinitiators (camphorquinone (CQ) and phenyl propanodione (PPD) and that of a co-initiator (N,N-dimethyl-p-toluidine) were also analyzed. When only the CQ photoinitiator was used, a smaller amount of residual monomers was obtained, whereas a larger amount was obtained with PPD. When the two photoinitiators were used in the same matrix, however, no significant changes were observed in relation to the amount of residual TEGDMA monomers. For the addition of the co-initiator, there were no large changes in the extraction of residual monomers. The effect of the two photoactivation sources (halogen lamp and LED) led to small differences in the elution of the two monomers, although all of the resins differed significantly when photoactivated with a LED. Quantum chemical calculations using Density Functional Theory were carried out to characterize several molecular properties of each monomer. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. First observation of density profile in directly laser-driven polystyrene targets for ablative Rayleigh-Taylor instability research

    International Nuclear Information System (INIS)

    Fujioka, Shinsuke; Shiraga, Hiroyuki; Nishikino, Masaharu; Shigemori, Keisuke; Sunahara, Atsushi; Nakai, Mitsuo; Azechi, Hiroshi; Nishihara, Katsunobu; Yamanaka, Tatsuhiko

    2003-01-01

    The temporal evolution of the density profile of a directly laser-driven polystyrene target was observed for the first time using an x-ray penumbral imaging technique coupled with side-on x-ray backlighting at the GEKKO XII [C. Yamanaka et al., IEEE J. Quantum Electron. QE-17, 1639 (1981)]-High Intensity Plasma Experimental Research laser facility (I L =0.7x10 14 W/cm 2 , λ L =0.35 μm). This density measurement makes it possible to experimentally confirm all physical parameters [γ(k),k,g,m,ρ a ,L m ] appearing in the modified Takabe formula for the growth rate of the ablative Rayleigh-Taylor instability. The measured density profiles were well reproduced by a one-dimensional hydrodynamic simulation code. The density measurement contributes toward fully understanding the ablative Rayleigh-Taylor instability

  20. Solubility of mixed monomers of tetrafluoroethylene and propylene in water and latex

    International Nuclear Information System (INIS)

    Watanabe, Hiromasa; Okamoto, Jiro

    1978-03-01

    For kinetical analysis of the emulsion copolymerization of tetrafluoroethylene with propylene and selection of the optimum reaction conditions, the monomer concentrations and composition of the polymer particle were measured and the relations with reaction conditions were determined. Solubilities of tetrafluoroethylene and propylene in water increase with pressure. solubility of propylene is larger than that of tetrafluoroethylene. Solubility of the mixed monomers in water and latex increases with pressure and propylene concentration and decreases with temperature. Propylene concentration in the dissolved monomers is dependent on its concentration in the gas phase and independent of pressure and temperature. The monomer concentrations and the composition were estimated from measurements. Under propylene concentration in the gas phase of 0 to 40 wt % at 30 Kg/cm 2 G and 40 0 C, the monomer concentration and propylene fraction of the polymer particle are 17 -- 27% and 0 -- 62% respectively. The amount of propylene in the particle increases with its fraction in the gas phase, but the amount of tetrafluoroethylene is independent of its fraction in the gas phase. Monomer composition of the polymer particle is dependent on monomer composition of the gas phase and independent of temperature and pressure. The concentration in the polymer particle is 17% at propylene concentration 10 mole % in the gas phase. (auth.)

  1. Thermodynamics of swelling of latex particles with two monomers: a sensitivity analysis

    NARCIS (Netherlands)

    Maxwell, I.A.; Noel, E.F.J.; Schoonbrood, H.A.S.; German, A.L.

    1993-01-01

    A sensitivity anal. is performed to det. at what conditions the simplified model for swelling of latex particles by two monomers or two solvents is valid. This model proposes that, inter alia, the fractions of two monomers in the latex particles and in the monomer droplets are equal. The model is a

  2. Retrieval of Electron Density Profile for KOMPSAT-5 GPS Radio Occultation

    Directory of Open Access Journals (Sweden)

    Woo-Kyoung Lee

    2007-12-01

    Full Text Available The AOPOD (Atmosphere Occultation and Precision Orbit Determination system, the secondary payload of KOMPSAT (KOrea Multi-Purpose SATellite-5 scheduled to be launched in 2010, shall provide GPS radio occultation data. In this paper, we simulated the GPS radio occultation characteristic of KOMPSAT-5 and retrieved electron density profiles using KROPS (KASI Radio Occultation Processing Software. The electron density retrieved from CHAMP (CHAllenging Minisatellite Payload GPS radio occultation data on June 20, 2004 was compared with IRI (International Reference Ionosphere - 2001, PLP (Planar Langmuir Probe, and ionosonde measurements. When the result was compared with ionosonde measurements, the discrepancies were 5 km on the F_2 peak height (hmF_2 and 3×10^{10} el/m^3 on the electron density of the F_2 peak height (NmF_2. By comparing with the Langmuir Probe measurements of CHAMP satellite (PLP, both agrees with 1.6×10^{11} el/m^3 at the height of 365.6 km.

  3. Analytic expressions for mode conversion in a plasma with a parabolic density profile: Generalized results

    International Nuclear Information System (INIS)

    Hinkel-Lipsker, D.E.; Fried, B.D.; Morales, G.J.

    1993-01-01

    This study provides an analytic solution to the general problem of mode conversion in an unmagnetized plasma. Specifically, an electromagnetic wave of frequency ω propagating through a plasma with a parabolic density profile of scale length L p is examined. The mode conversion points are located a distance Δ 0 from the peak of the profile, where the electron plasma frequency ω p (z) matches the wave frequency ω. The corresponding reflection, transmission, and mode conversion coefficients are expressed analytically in terms of parabolic cylinder functions for all values of Δ 0 . The method of solution is based on a source approximation technique that is valid when the electromagnetic and electrostatic scale lengths are well separated. For large Δ 0 , i.e., (cL p /ω) 1/2 much-lt Δ 0 p , the appropriately scaled result [D. E. Hinkel-Lipsker et al., Phys. Fluids B 4, 559 (1992)] for a linear density profile is recovered as the parabolic cylinder functions asymptotically become Airy functions. When Δ 0 →0, the special case of conversion at the peak of the profile [D. E. Hinkel-Lipsker et al., Phys. Fluids B 4, 1772 (1992)] is obtained

  4. Model-based Optimization and Feedback Control of the Current Density Profile Evolution in NSTX-U

    Science.gov (United States)

    Ilhan, Zeki Okan

    Nuclear fusion research is a highly challenging, multidisciplinary field seeking contributions from both plasma physics and multiple engineering areas. As an application of plasma control engineering, this dissertation mainly explores methods to control the current density profile evolution within the National Spherical Torus eXperiment-Upgrade (NSTX-U), which is a substantial upgrade based on the NSTX device, which is located in Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ. Active control of the toroidal current density profile is among those plasma control milestones that the NSTX-U program must achieve to realize its next-step operational goals, which are characterized by high-performance, long-pulse, MHD-stable plasma operation with neutral beam heating. Therefore, the aim of this work is to develop model-based, feedforward and feedback controllers that can enable time regulation of the current density profile in NSTX-U by actuating the total plasma current, electron density, and the powers of the individual neutral beam injectors. Motivated by the coupled, nonlinear, multivariable, distributed-parameter plasma dynamics, the first step towards control design is the development of a physics-based, control-oriented model for the current profile evolution in NSTX-U in response to non-inductive current drives and heating systems. Numerical simulations of the proposed control-oriented model show qualitative agreement with the high-fidelity physics code TRANSP. The next step is to utilize the proposed control-oriented model to design an open-loop actuator trajectory optimizer. Given a desired operating state, the optimizer produces the actuator trajectories that can steer the plasma to such state. The objective of the feedforward control design is to provide a more systematic approach to advanced scenario planning in NSTX-U since the development of such scenarios is conventionally carried out experimentally by modifying the tokamak's actuator

  5. Theoretical prediction and experimental determination of the effect of mold characteristics on temperature and monomer conversion fraction profiles during polymerization of a PMMA-based bone cement.

    Science.gov (United States)

    Vallo, Claudia I

    2002-01-01

    The present work is concerned with applications of a kinetic model for free-radical polymerization of a polymethylmethacrylate-based bone cement. Autocatalytic behavior at the first part of the reaction as well as a diffusion control phenomenon near vitrification are described by the model. Comparison of theoretical computations with experimental measurements for the temperature evolution during batch casting demonstrated the capacity of the proposed model to represent the kinetic behavior of the polymerization reaction. Temperature evolution and monomer conversion were simulated for the cure of the cement in molds made of different materials. The maximum monomer conversion fraction was markedly influenced by the physical properties of the mold material. The unreacted monomer acts as a plasticizer that influences the mechanical behavior of the cement. Hence, the same cement formulation cured in molds of different materials may result in different mechanical response because of the differences in the amounts of residual monomer. Standardization of the mold type to prepare specimens for the mechanical characterization of bone cements is recommended. Theoretical prediction of temperature evolution during hip replacement indicated that for cement thickness lower than 6 mm the peak temperature at the bone-cement interface was below the limit stated for thermal injury (50 degrees C for more than 1 min). The use of thin cement layers is recommended to diminish the risk of thermal injury; however, it is accompanied by an increase in the amount of unreacted monomer present in the cured material. Copyright 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 627-642, 2002

  6. Mars Global Surveyor Radio Science Electron Density Profiles: Interannual Variability and Implications for the Neutral Atmosphere

    Science.gov (United States)

    Bougher, S. W.; Engel, S.; Hinson, D. P.; Murphy, J. R.

    2003-01-01

    The Mars Global Surveyor (MGS) Radio Science (RS) experiment employs an ultrastable oscillator aboard the spacecraft. The signal from the oscillator to Earth is refracted by the Martian ionosphere, allowing retrieval of electron density profiles versus radius and geopotential. The present analysis is carried out on five sets of occultation measurements: (1) four obtained near northern summer solstice (Ls = 74-116, near aphelion) at high northern latitudes (64.7-77.6N), and (2) one set of profiles approaching equinox conditions (Ls = 135- 146) at high southern latitudes (64.7-69.1S). Electron density profiles (95 to 200 km) are examined over a narrow range of solar zenith angles (76.5-86.9 degrees) for local true solar times of (1) 3-4 hours and (2) 12.1 hours. Variations spanning 1-Martian year are specifically examined in the Northern hemisphere.

  7. A density functional theory-based investigation of adhesion of poly(butylene terephthalate) on aluminum

    International Nuclear Information System (INIS)

    David, Melanie; Roman, Tanglaw; Nakanishi, Hiroshi; Kasai, Hideaki; Ando, Naoki; Naritomi, Masanori

    2006-01-01

    We investigate the adhesion of PBT on aluminum using density functional theory-based calculations. The geometric structure of the PBT monomer is first relaxed then an aluminum atom is connected to the monomer in different orientations. We calculate their total energies and determine the orientation that gives the strongest binding between the monomer and the aluminum atom. Binding is strongest when the Al connects linearly with the carbonyl oxygen in the ester group. We present binding mechanisms and total energy relationships for the different orientations

  8. Polymerization of Polar Monomers from a Theoretical Perspective

    KAUST Repository

    Alghamdi, Miasser

    2016-10-11

    Density functional theory calculations have been used to investigate catalytic mechanism of polymer formation containing polar groups, from the synthesis of the monomer to the synthesis of the macromolecule. In the spirit of a sustainable and green chemistry, we initially focused attention on the coupling of CO2 as economically convenient and recyclable C1 source with C2H4 to form acrylate and/or butirro-lactone, two important polar monomers. In this process formation of a mettallolactone via oxidative coupling of CO2 and C2H4 is an important intermediate. Given this background, we explored in detail (chapter-3) several Ni based catalysts for CO2 coupling with C2H4 to form acrylate. In this thesis we report on the competitive reaction mechanisms (inner vs outer sphere) for the oxidative coupling of CO2 and ethylene for a set of 11 Ni-based complexes containing bisphosphine ligands. In another effort, considering incorporation of a C=C bond into a metal-oxygen-Functional-Group moiety is a challenging step in several polymerization reactions, we explored the details of this reaction (chapter4) using two different catalysts that are capable to perform this reaction in the synthesis of heterocycles. Specifically, the [Rh]-catalyzed intramolecular alkoxyacylation ([Rh] = [RhI(dppp)+] (dppp, 1,3-Bis-diphenylphosphino-propane), and the [Pd]/BPh3 intramolecular alkoxyfunctionalizations. Rest of the thesis we worked on understanding the details of the polymerization of polar monomers using organocatalysts based on N-heterocyclic carbenes (NHC) or N-heterocyclic olefins (NHO). In particular (chapter-5) we studied the polymerization of N-methyl N-carboxy- anhydrides, towards cyclic poly(N-substituted glycine)s, promoted by NHC catalysts. In good agreement with the experimental findings, we demonstrated that NHC promoted ring opening polymerization of N-Me N-Carboxyanhydrides may proceed via two different catalytic pathways. In a similar effort we studied polymerization of

  9. A Simultaneous Density-Integral System for Estimating Stem Profile and Biomass: Slash Pine and Willow Oak

    Science.gov (United States)

    Bernard R. Parresol; Charles E. Thomas

    1996-01-01

    In the wood utilization industry, both stem profile and biomass are important quantities. The two have traditionally been estimated separately. The introduction of a density-integral method allows for coincident estimation of stem profile and biomass, based on the calculus of mass theory, and provides an alternative to weight-ratio methodology. In the initial...

  10. Improved density profile measurements in the C-2U advanced beam-driven Field-Reversed Configuration (FRC) plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Beall, M., E-mail: mbeall@trialphaenergy.com; Deng, B. H.; Gota, H. [Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688 (United States)

    2016-11-15

    In the prior C-2 experiment, electron density was measured using a two-color 6-chord CO{sub 2}/HeNe interferometer. Analysis shows that high-frequency common mode phase noise can be reduced by a factor of 3 by constructing a reference chord. In the system upgrade from C-2 to C-2U a 4-chord far-infrared laser interferometer was developed, which demonstrated superior sensitivity (1 × 10{sup 16} m{sup −2} at >1 MHz bandwidth) and solved the under spatial sampling issue of the C-2 interferometer system. Improved density-profile measurement results are presented in this paper, including evidence of fast-ion modified density profile and stabilization of the n = 1 plasma wobble mode.

  11. Evaluation of level of impregnation monomers in hydrotalcite

    International Nuclear Information System (INIS)

    Carmo, Danieli M. do; Machado, Jacson S.C.; Oliveira, Marcelo F.L.; Oliveira, Marcia G.; Soares, Bluma G.

    2011-01-01

    To evaluate the impregnation degree of 1,6-hexamethylene diisocyanate and 1,4-butanediol monomers in hydrotalcite clays it was prepared dispersions with mixing ratio 1:100 (clay/monomer), using the Ultraturrax and Ultrasound. Subsequently the samples were characterized by Fourier Transform Infrared Spectroscopy and X-ray Diffraction. Swelling tests and Tyndall effect were used to illustrate the different dispersions. The results indicated a strong interaction between the hydrotalcite with 1,6-hexamethylene diisocyanate, favoring the formation of intercalated structures. (author)

  12. The Off-rate of Monomers Dissociating from Amyloid-β Protofibrils*

    Science.gov (United States)

    Grüning, Clara S. R.; Klinker, Stefan; Wolff, Martin; Schneider, Mario; Toksöz, Küpra; Klein, Antonia N.; Nagel-Steger, Luitgard; Willbold, Dieter; Hoyer, Wolfgang

    2013-01-01

    The interconversion of monomers, oligomers, and amyloid fibrils of the amyloid-β peptide (Aβ) has been implicated in the pathogenesis of Alzheimer disease. The determination of the kinetics of the individual association and dissociation reactions is hampered by the fact that forward and reverse reactions to/from different aggregation states occur simultaneously. Here, we report the kinetics of dissociation of Aβ monomers from protofibrils, prefibrillar high molecular weight oligomers previously shown to possess pronounced neurotoxicity. An engineered binding protein sequestering specifically monomeric Aβ was employed to follow protofibril dissociation by tryptophan fluorescence, precluding confounding effects of reverse or competing reactions. Aβ protofibril dissociation into monomers follows exponential decay kinetics with a time constant of ∼2 h at 25 °C and an activation energy of 80 kJ/mol, values typical for high affinity biomolecular interactions. This study demonstrates the high kinetic stability of Aβ protofibrils toward dissociation into monomers and supports the delineation of the Aβ folding and assembly energy landscape. PMID:24247242

  13. Step growth of an AB2 monomer, with cycle formation

    DEFF Research Database (Denmark)

    Cameron, Colin; Fawcett, Allan H.; Hetherington, Cecil R.

    1998-01-01

    A computer-based lattice model of the step growth reaction of an AB2 monomer, the next elaborate system after an AB monomer, has been devised that allows the simultaneous and explicit occurrence of inter- and intramolecular reactions of A and B groups of the flexible and moving molecules according...... with fractal characteristics. Growth stops when each molecule contains a cycle. For the model explored, in which six lattice sites are used for each monomer, the limiting value of the number average degree of polymerization, 〈x〉n,∞, is 14.6(±0.3) (after infinite time). The occurrence within the system of rings...... of m residues (m=1,2,3,...) is found to depend upon m and the extent of reaction of the A groups, pa, according to Rm=C0pm am-2.71, the constant C0 reflecting the structure of the lattice and the monomer, and being shown to determine the final degree of polymerization. The exponent of the integers m...

  14. Real-time control of the current density and pressure profiles in Jet

    International Nuclear Information System (INIS)

    Mazon, D.; Moreau, D.; Litaudon, X.; Joffrin, E.; Laborde, L.; Zabeo, L.; Crisanti, F.; Riva, M.; Felton, R.; Murari, A.; Tala, T.

    2003-01-01

    In order to ultimately control internal transport barriers during advanced operation scenarios, new algorithms using a truncated singular value decomposition of a linearized model operator have been implemented in the JET real-time controller, with the potentiality of retaining the distributed nature of plasma parameter profiles. First experiments using the simplest, lumped-parameter, version of this technique have been dedicated to the feedback control of the current density profile in a negative shear plasma using three heating and current drive actuators, namely neutral beam injection (NBI), ion cyclotron resonant frequency heating (ICRH) and lower hybrid current drive (LHCD). Successful control of the safety factor profile has been achieved on the time scale of the current redistribution time, first during an extended preheat phase with only LHCD as actuator and, then, in quasi steady-state conditions during the main heating phase of a discharge, using the three heating and current drive actuators

  15. Crystallization and preliminary crystallographic investigation of a low-pH native insulin monomer with flexible behaviour.

    Science.gov (United States)

    Zhang, Youshang; Whittingham, Jean L; Turkenburg, Johan P; Dodson, Eleanor J; Brange, Jens; Dodson, G Guy

    2002-01-01

    Insulin naturally aggregates as dimers and hexamers, whose structures have been extensively analysed by X-ray crystallography. Structural determination of the physiologically relevant insulin monomer, however, is an unusual challenge owing to the difficulty in finding solution conditions in which the concentration of insulin is high enough for crystallization yet the molecule remains monomeric. By utilizing solution conditions known to inhibit insulin assembly, namely 20% acetic acid, crystals of insulin in the monomeric state have been obtained. The crystals are strongly diffracting and a data set extending to 1.6 A has recently been collected. The crystals nominally belong to the space group I422, with unit-cell parameters a = b = 57.80, c = 54.61 A, giving rise to one molecule in the asymmetric unit. Preliminary electron-density maps show that whilst most of the insulin monomer is well ordered and similar in conformation to other insulin structures, parts of the B-chain C-terminus main chain adopt more than one conformation.

  16. 46 CFR 151.50-34 - Vinyl chloride (vinyl chloride monomer).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Vinyl chloride (vinyl chloride monomer). 151.50-34... chloride (vinyl chloride monomer). (a) Copper, aluminum, magnesium, mercury, silver, and their alloys shall... equipment that may come in contact with vinyl chloride liquid or vapor. (b) Valves, flanges, and pipe...

  17. Topside electron density: comparison of experimental and IRI model profiles during low solar activity period

    International Nuclear Information System (INIS)

    Alazo, K.; Coisson, P.; Radicella, S.M.

    2003-01-01

    The pattern of the topside electron density profiles is not yet very well represented by the IRI model. In this work the topside profiles obtained by the ISIS-2 satellite during low solar activity conditions are compared to those modeled by IRI. We take the quantitative parameter ε to measure the deviation of the model from the observed profiles. The results showed that the IRI overestimation of the topside profile is higher for low dip latitudes. The dispersion of the epsilon values is from 40 to 140%, more in equinoctial months and some lower for Winter. The best modeling is about 20% to 40% in middle and high latitudes of the North Hemisphere. (author)

  18. Constraining the Milky Way dark matter density profile with gamma-rays with Fermi-LAT

    International Nuclear Information System (INIS)

    Bernal, Nicolás; Palomares-Ruiz, Sergio

    2012-01-01

    We study the abilities of the Fermi-LAT instrument on board of the Fermi mission to simultaneously constrain the Milky Way dark matter density profile and some dark matter particle properties, as annihilation cross section, mass and branching ratio into dominant annihilation channels. A single dark matter density profile is commonly assumed to determine the capabilities of gamma-ray experiments to extract dark matter properties or to set limits on them. However, our knowledge of the Milky Way halo is far from perfect, and thus in general, the obtained results are too optimistic. Here, we study the effect these astrophysical uncertainties would have on the determination of dark matter particle properties and conversely, we show how gamma-ray searches could also be used to learn about the structure of the Milky Way halo, as a complementary tool to other type of observational data that study the gravitational effect caused by the presence of dark matter. In addition, we also show how these results would improve if external information on the annihilation cross section and on the local dark matter density were included and compare our results with the predictions from numerical simulations

  19. Novel lipoprotein density profiling in healthy dogs of various breeds, healthy miniature schnauzers, and miniature schnauzers with hyperlipidemia

    Science.gov (United States)

    2013-01-01

    Background Despite the importance of abnormalities in lipoprotein metabolism in clinical canine medicine, the fact that most previously used methods for lipoprotein profiling are rather laborious and time-consuming has been a major obstacle to the wide clinical application and use of lipoprotein profiling in this species. The aim of the present study was to assess the feasibility of a continuous lipoprotein density profile (CLPDP) generated within a bismuth sodium ethylenediaminetetraacetic acid (NaBiEDTA) density gradient to characterize and compare the lipoprotein profiles of healthy dogs of various breeds, healthy Miniature Schnauzers, and Miniature Schnauzers with primary hypertriacylglycerolemia. A total of 35 healthy dogs of various breeds with serum triacylglycerol (TAG) and cholesterol concentrations within their respective reference intervals were selected for use as a reference population. Thirty-one Miniature Schnauzers with serum TAG and cholesterol concentrations within their respective reference intervals and 31 Miniature Schnauzers with hypertriacylglyceridemia were also included in the study. Results The results suggest that CLPDP using NaBiEDTA provides unique diagnostic information in addition to measurements of serum TAG and cholesterol concentrations and that it is a useful screening method for dogs with suspected lipoprotein metabolism disorders. Using the detailed and continuous density distribution information provided by the CLPDP, important differences in lipoprotein profiles can be detected even among dogs that have serum TAG and cholesterol concentrations within the reference interval. Miniature Schnauzers with serum TAG and cholesterol concentrations within the reference interval had significantly different lipoprotein profiles than dogs of various other breeds. In addition, it was further established that specific lipoprotein fractions are associated with hypertriacylglyceridemia in Miniature Schnauzers. Conclusions The results of the

  20. Synthesis and characterization of novel organotin carboxylate maleimide monomers and copolymers

    Directory of Open Access Journals (Sweden)

    2009-06-01

    Full Text Available Two novel tributyltin carboxylate maleimide monomers, tributyltin(maleimidoacetate and tributyltin(4-maleimidobenzoate, were synthesized by condensation reaction of maleimidoacetic acid or 4-maleimidobenzoic acid with bis(tributyltin oxide. Copolymerization of these monomers with styrene was carried in dioxane at 70°C using asobisisobutyronitrile as free radical initiator. The structures of monomers and copolymers were confirmed by FT-IR (Fourier Transform Infrared, 1H and 13C NMR (nuclear magnetic resonance spectroscopy and elemental analysis. The copolymers were characterized by solubility and thermal analysis.

  1. Generalized saddle point condition for ignition in a tokamak reactor with temperature and density profiles

    International Nuclear Information System (INIS)

    Mitari, O.; Hirose, A.; Skarsgard, H.M.

    1989-01-01

    In this paper, the concept of a generalized ignition contour map, is extended to the realistic case of a plasma with temperature and density profiles in order to study access to ignition in a tokamak reactor. The generalized saddle point is found to lie between the Lawson and ignition conditions. If the height of the operation path with Goldston L-mode scaling is higher than the generalized saddle point, a reactor can reach ignition with this scaling for the case with no confinement degradation effect due to alpha-particle heating. In this sense, the saddle point given in a general form is a new criterion for reaching ignition. Peaking the profiles for the plasma temperature and density can lower the height of the generalized saddle point and help a reactor to reach ignition. With this in mind, the authors can judge whether next-generation tokamaks, such as Compact Ignition Tokamak, Tokamak Ignition/Burn Experimental Reactor, Next European Torus, Fusion Experimental Reactor, International Tokamak Reactor, and AC Tokamak Reactor, can reach ignition with realistic profile parameters and an L-mode scaling law

  2. Method of measuring a profile of the density of charged particles in a particle beam

    International Nuclear Information System (INIS)

    Hyman, L.G.; Jankowski, D.J.

    1975-01-01

    A profile of the relative density of charged particles in a beam is obtained by disposing a number of rods parallel to each other in a plane perpendicular to the beam and shadowing the beam. A second number of rods is disposed perpendicular to the first rods in a plane perpendicular to the beam and also shadowing the beam. Irradiation of the rods by the beam of charged particles creates radioactive isotopes in a quantity proportional to the number of charged particles incident upon the rods. Measurement of the radioactivity of each of the rods provides a measure of the quantity of radioactive material generated thereby and, together with the location of the rods, provides information sufficient to identify a profile of the density of charged particles in the beam

  3. Kinetics of monomer biodegradation in soil.

    Science.gov (United States)

    Siotto, Michela; Sezenna, Elena; Saponaro, Sabrina; Innocenti, Francesco Degli; Tosin, Maurizio; Bonomo, Luca; Mezzanotte, Valeria

    2012-01-01

    In modern intensive agriculture, plastics are used in several applications (i.e. mulch films, drip irrigation tubes, string, clips, pots, etc.). Interest towards applying biodegradable plastics to replace the conventional plastics is promising. Ten monomers, which can be applied in the synthesis of potentially biodegradable polyesters, were tested according to ASTM 5988-96 (standard respirometric test to evaluate aerobic biodegradation in soil by measuring the carbon dioxide evolution): adipic acid, azelaic acid, 1,4-butanediol, 1,2-ethanediol, 1,6-hexanediol, lactic acid, glucose, sebacic acid, succinic acid and terephthalic acid. Eight replicates were carried out for each monomer for 27-45 days. The numerical code AQUASIM was applied to process the CO₂ experimental data in order to estimate values for the parameters describing the different mechanisms occurring to the monomers in soil: i) the first order solubilization kinetic constant, K(sol) (d⁻¹); ii) the first order biodegradation kinetic constant, K(b) (d⁻¹); iii) the lag time in biodegradation, t(lag) (d); and iv) the carbon fraction biodegraded but not transformed into CO₂, Y (-). The following range of values were obtained: [0.006 d⁻¹, 6.9 d⁻¹] for K(sol), [0.1 d⁻¹, 1.2 d⁻¹] for K(b), and [0.32-0.58] for Y; t(lag) was observed for azelaic acid, 1,2-ethanediol, and terephthalic acid, with estimated values between 3.0 e 4.9 d. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Measurements of electron density and temperature profiles in a gas blanket experiment

    International Nuclear Information System (INIS)

    Kuthy, A.

    1979-02-01

    Radial profiles of electron density, temperature and H sub(β) intensity are presented for the rotating plasma device F-1. The hydrogen filling pressure, the average magnetic field strength at the midplane, and the power input to the discharge have been varied in the ranges 10-100 mTorr, 0.25-0.5 Tesla, and 0.1 to 1.5 MW, respectively. These experiments have been performed with the main purpose of studying the gas blanket (cold-mantle) state of the plasma. It is shown, that a simple spectroscopic method can be used to derive the radial distribution of the electron temperature in such plasmas. The observed peak temperatures and densities are in agreement with earlier theoretical estimates. (author)

  5. Characteristic of Polymer-Impregnated Cement Mortar: Composites: Bulk Density and Microstructure

    International Nuclear Information System (INIS)

    Younes, M.M.; Abo-El-Enein, S.A.; El-Saft, M.M.; Sadek, M.A.; Zohdy, K.M.

    2010-01-01

    The effect of radiation initiated polymerization of some monomers on the physical properties of polymer-incorporated mortar was studied. The monomers used were: castor oil (C.O.), 4, 4'-diphenylmethane diisocyanate (MDI) and methyl methacrylate (MMA). Polymerization was carried out by subjecting the monomer-impregnated mortar specimens to different doses of gamma radiation. Where polyurethane (pu) and polyurethane -methyl methacrylate copolymers were formed within the pore system. The influence of polymer impregnation on the various physico-mechanical characteristics of the resulting composites was studied with respect to bulk density and polymer loading. Scanning electron microscopy (SEM) was employed to study the micro-structural characteristics of the neat hardened Ordinary Portland Cement (OPC) mortar pastes and their polymer-impregnated composites

  6. Radial Surface Density Profiles of Gas and Dust in the Debris Disk around 49 Ceti

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, A. Meredith; Lieman-Sifry, Jesse; Flaherty, Kevin M.; Daley, Cail M. [Department of Astronomy, Van Vleck Observatory, Wesleyan University, 96 Foss Hill Drive, Middletown, CT 06459 (United States); Roberge, Aki [Exoplanets and Stellar Astrophysics Laboratory, NASA Goddard Space Flight Center, Code 667, Greenbelt, MD 20771 (United States); Kóspál, Ágnes; Moór, Attila; Ábrahám, Peter [Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, P.O. Box 67, 1525 Budapest (Hungary); Kamp, Inga [Kapteyn Astronomical Institute, University of Groningen, Postbus 800, 9700 AV Groningen (Netherlands); Wilner, David J.; Andrews, Sean M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51, Cambridge, MA 02138 (United States); Kastner, Joel H., E-mail: amhughes@astro.wesleyan.edu [Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States)

    2017-04-20

    We present ∼0.″4 resolution images of CO(3–2) and associated continuum emission from the gas-bearing debris disk around the nearby A star 49 Ceti, observed with the Atacama Large Millimeter/Submillimeter Array (ALMA). We analyze the ALMA visibilities in tandem with the broadband spectral energy distribution to measure the radial surface density profiles of dust and gas emission from the system. The dust surface density decreases with radius between ∼100 and 310 au, with a marginally significant enhancement of surface density at a radius of ∼110 au. The SED requires an inner disk of small grains in addition to the outer disk of larger grains resolved by ALMA. The gas disk exhibits a surface density profile that increases with radius, contrary to most previous spatially resolved observations of circumstellar gas disks. While ∼80% of the CO flux is well described by an axisymmetric power-law disk in Keplerian rotation about the central star, residuals at ∼20% of the peak flux exhibit a departure from axisymmetry suggestive of spiral arms or a warp in the gas disk. The radial extent of the gas disk (∼220 au) is smaller than that of the dust disk (∼300 au), consistent with recent observations of other gas-bearing debris disks. While there are so far only three broad debris disks with well characterized radial dust profiles at millimeter wavelengths, 49 Ceti’s disk shows a markedly different structure from two radially resolved gas-poor debris disks, implying that the physical processes generating and sculpting the gas and dust are fundamentally different.

  7. Binding interactions between suberin monomer components and pesticides

    Energy Technology Data Exchange (ETDEWEB)

    Olivella, M.À., E-mail: angels.olivella@udg.edu [Department of Chemical Engineering, Escola Politècnica Superior, Universitat de Girona, Maria Aurèlia Capmany, 61, 17071 Girona (Spain); Bazzicalupi, C.; Bianchi, A. [Department of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia, 3, 50019 Sesto Fiorentino (Italy); Río, J.C. del [Instituto de Recursos Naturales y Agrobiología de Sevilla, Consejo Superior de Investigaciones Científicas, P.O. Box 1052, 41080 Seville (Spain); Fiol, N.; Villaescusa, I. [Department of Chemical Engineering, Escola Politècnica Superior, Universitat de Girona, Maria Aurèlia Capmany, 61, 17071 Girona (Spain)

    2015-09-15

    Understanding the role of biomacromolecules and their interactions with pollutants is a key for elucidating the sorption mechanisms and making an accurate assessment of the environmental fate of pollutants. The knowledge of the sorption properties of the different constituents of these biomacromolecules may furnish a significant contribution to this purpose. Suberin is a very abundant biopolymer in higher plants. In this study, suberin monomers isolated from cork were analyzed by thermally-assisted methylation with tetramethylammonium hydroxide (TMAH) in a pyrolysis unit coupled to gas chromatography–mass spectrometry (GC/MS). The isolated monomer mixture was used to study the sorption of three pesticides (isoproturon, methomyl and oxamyl). The modes of pesticide–sorbent interactions were analyzed by means of two modeling calculations, the first one representing only the mixture of suberin monomers used in the sorption study, and the second one including glycerol to the mixture of suberin monomers, as a building block of the suberin molecule. The results indicated that the highest sorption capacity exhibited by the sorbent was for isoproturon (33%) being methomyl and oxamyl sorbed by the main suberin components to a lesser extent (3% and < 1%, respectively). In addition to van der Waals interactions with the apolar region of sorbent and isoproturon, modeling calculations evidenced the formation of a hydrogen bond between the isoproturon NH group and a carboxylic oxygen atom of a suberin monomer. In the case of methomyl and oxamyl only weak van der Waals interactions stabilize the pesticide–sorbent adducts. The presence of glycerol in the model provoked significant changes in the interactions with isoproturon and methomyl. - Highlights: • Suberin has low affinity to retain pesticides of aliphatic character. • Suberin has a moderate affinity to adsorb isoproturon. • Modeling calculations show that apolar portion of suberin interacts with isoproturon.

  8. Binding interactions between suberin monomer components and pesticides

    International Nuclear Information System (INIS)

    Olivella, M.À.; Bazzicalupi, C.; Bianchi, A.; Río, J.C. del; Fiol, N.; Villaescusa, I.

    2015-01-01

    Understanding the role of biomacromolecules and their interactions with pollutants is a key for elucidating the sorption mechanisms and making an accurate assessment of the environmental fate of pollutants. The knowledge of the sorption properties of the different constituents of these biomacromolecules may furnish a significant contribution to this purpose. Suberin is a very abundant biopolymer in higher plants. In this study, suberin monomers isolated from cork were analyzed by thermally-assisted methylation with tetramethylammonium hydroxide (TMAH) in a pyrolysis unit coupled to gas chromatography–mass spectrometry (GC/MS). The isolated monomer mixture was used to study the sorption of three pesticides (isoproturon, methomyl and oxamyl). The modes of pesticide–sorbent interactions were analyzed by means of two modeling calculations, the first one representing only the mixture of suberin monomers used in the sorption study, and the second one including glycerol to the mixture of suberin monomers, as a building block of the suberin molecule. The results indicated that the highest sorption capacity exhibited by the sorbent was for isoproturon (33%) being methomyl and oxamyl sorbed by the main suberin components to a lesser extent (3% and < 1%, respectively). In addition to van der Waals interactions with the apolar region of sorbent and isoproturon, modeling calculations evidenced the formation of a hydrogen bond between the isoproturon NH group and a carboxylic oxygen atom of a suberin monomer. In the case of methomyl and oxamyl only weak van der Waals interactions stabilize the pesticide–sorbent adducts. The presence of glycerol in the model provoked significant changes in the interactions with isoproturon and methomyl. - Highlights: • Suberin has low affinity to retain pesticides of aliphatic character. • Suberin has a moderate affinity to adsorb isoproturon. • Modeling calculations show that apolar portion of suberin interacts with isoproturon.

  9. Effects of low central fuelling on density and ion temperature profiles in reversed shear plasmas on JT-60U

    Energy Technology Data Exchange (ETDEWEB)

    Takenaga, H; Ide, S; Sakamoto, Y; Fujita, T [Japan Atomic Energy Agency, Naka Ibaraki 311-0193 (Japan)], E-mail: takenaga.hidenobu@jaea.go.jp

    2008-07-15

    Effects of low central fuelling on density and ion temperature profiles have been investigated using negative ion based neutral beam injection and electron cyclotron heating (ECH) in reversed shear plasmas on JT-60U. Strong internal transport barrier (ITB) was maintained in density and ion temperature profiles, when central fuelling was decreased by switching positive ion based neutral beam injection to ECH after the strong ITB formation. Similar density and ion temperature ITBs were formed for the low and high central fuelling cases during the plasma current ramp-up phase. Strong correlation between the density gradient and the ion temperature gradient was observed, indicating that particle transport and ion thermal transport are strongly coupled or the density gradient assists the ion temperature ITB formation through suppression of drift wave instabilities such as ion temperature gradient mode. These results support that the density and ion temperature ITBs can be formed under reactor relevant conditions.

  10. Effects of low central fuelling on density and ion temperature profiles in reversed shear plasmas on JT-60U

    Science.gov (United States)

    Takenaga, H.; Ide, S.; Sakamoto, Y.; Fujita, T.; JT-60 Team

    2008-07-01

    Effects of low central fuelling on density and ion temperature profiles have been investigated using negative ion based neutral beam injection and electron cyclotron heating (ECH) in reversed shear plasmas on JT-60U. Strong internal transport barrier (ITB) was maintained in density and ion temperature profiles, when central fuelling was decreased by switching positive ion based neutral beam injection to ECH after the strong ITB formation. Similar density and ion temperature ITBs were formed for the low and high central fuelling cases during the plasma current ramp-up phase. Strong correlation between the density gradient and the ion temperature gradient was observed, indicating that particle transport and ion thermal transport are strongly coupled or the density gradient assists the ion temperature ITB formation through suppression of drift wave instabilities such as ion temperature gradient mode. These results support that the density and ion temperature ITBs can be formed under reactor relevant conditions.

  11. Fluid and gyrokinetic modelling of particle transport in plasmas with hollow density profiles

    International Nuclear Information System (INIS)

    Tegnered, D; Oberparleiter, M; Nordman, H; Strand, P

    2016-01-01

    Hollow density profiles occur in connection with pellet fuelling and L to H transitions. A positive density gradient could potentially stabilize the turbulence or change the relation between convective and diffusive fluxes, thereby reducing the turbulent transport of particles towards the center, making the fuelling scheme inefficient. In the present work, the particle transport driven by ITG/TE mode turbulence in regions of hollow density profiles is studied by fluid as well as gyrokinetic simulations. The fluid model used, an extended version of the Weiland transport model, Extended Drift Wave Model (EDWM), incorporates an arbitrary number of ion species in a multi-fluid description, and an extended wavelength spectrum. The fluid model, which is fast and hence suitable for use in predictive simulations, is compared to gyrokinetic simulations using the code GENE. Typical tokamak parameters are used based on the Cyclone Base Case. Parameter scans in key plasma parameters like plasma β, R/L T , and magnetic shear are investigated. It is found that β in particular has a stabilizing effect in the negative R/L n region, both nonlinear GENE and EDWM show a decrease in inward flux for negative R/L n and a change of direction from inward to outward for positive R/L n . This might have serious consequences for pellet fuelling of high β plasmas. (paper)

  12. On the contact values of the density profiles in an electric double layer using density functional theory

    Directory of Open Access Journals (Sweden)

    L.B. Bhuiyan

    2012-06-01

    Full Text Available A recently proposed, local second contact value theorem [Henderson D., Boda D., J. Electroanal. Chem., 2005, Vol. 582, 16] for the charge profile of an electric double layer is used in conjunction with existing Monte Carlo data from the literature to assess the contact behavior of the electrode-ion distributions predicted by the density functional theory. The results for the contact values of the co- and counterion distributions and their product are obtained for the symmetric valency, restricted primitive model planar double layer for a range of electrolyte concentrations and temperatures. Overall the theoretical results satisfy the second contact value theorem reasonably well the agreement with the simulations being semi-quantitative or better. The product of the co- and counterion contact values as a function of the electrode surface charge density is qualitative with the simulations with increasing deviations at higher concentrations.

  13. High-resolution structure of a retroviral protease folded as a monomer

    International Nuclear Information System (INIS)

    Gilski, Miroslaw; Kazmierczyk, Maciej; Krzywda, Szymon; Zábranská, Helena; Cooper, Seth; Popović, Zoran; Khatib, Firas; DiMaio, Frank; Thompson, James; Baker, David; Pichová, Iva; Jaskolski, Mariusz

    2011-01-01

    The crystal structure of Mason–Pfizer monkey virus protease folded as a monomer has been solved by molecular replacement using a model generated by players of the online game Foldit. The structure shows at high resolution the details of a retroviral protease folded as a monomer which can guide rational design of protease dimerization inhibitors as retroviral drugs. Mason–Pfizer monkey virus (M-PMV), a D-type retrovirus assembling in the cytoplasm, causes simian acquired immunodeficiency syndrome (SAIDS) in rhesus monkeys. Its pepsin-like aspartic protease (retropepsin) is an integral part of the expressed retroviral polyproteins. As in all retroviral life cycles, release and dimerization of the protease (PR) is strictly required for polyprotein processing and virion maturation. Biophysical and NMR studies have indicated that in the absence of substrates or inhibitors M-PMV PR should fold into a stable monomer, but the crystal structure of this protein could not be solved by molecular replacement despite countless attempts. Ultimately, a solution was obtained in mr-rosetta using a model constructed by players of the online protein-folding game Foldit. The structure indeed shows a monomeric protein, with the N- and C-termini completely disordered. On the other hand, the flap loop, which normally gates access to the active site of homodimeric retropepsins, is clearly traceable in the electron density. The flap has an unusual curled shape and a different orientation from both the open and closed states known from dimeric retropepsins. The overall fold of the protein follows the retropepsin canon, but the C α deviations are large and the active-site ‘DTG’ loop (here NTG) deviates up to 2.7 Å from the standard conformation. This structure of a monomeric retropepsin determined at high resolution (1.6 Å) provides important extra information for the design of dimerization inhibitors that might be developed as drugs for the treatment of retroviral infections

  14. Synthesis and evaluation of novel siloxane-methacrylate monomers used as dentin adhesives.

    Science.gov (United States)

    Ge, Xueping; Ye, Qiang; Song, Linyong; Misra, Anil; Spencer, Paulette

    2014-09-01

    The objectives of this study were to synthesize two new siloxane-methacrylate (SM) monomers for application in dentin adhesives and to investigate the influence of different functionality of the siloxane-containing monomers on the adhesive photopolymerization, water sorption, and mechanical properties. Two siloxane-methacrylate monomers (SM1 and SM2) with four and eight methacrylate groups were synthesized. Dentin adhesives containing BisGMA, HEMA and the siloxane-methacrylate monomers were photo-polymerized. The experimental adhesives were compared with the control adhesive (HEMA/BisGMA, 45/55, w/w) and characterized with regard to degree of conversion (DC), water miscibility of the liquid resin, water sorption and dynamic mechanical analysis (DMA). The experimental adhesives exhibited improved water miscibility as compared to the control. When cured in the presence of 12 wt% water to simulate the wet environment of the mouth, the SM-containing adhesives showed DC comparable to the control. The experimental adhesives showed higher rubbery modulus than the control under dry conditions. Under wet conditions, the mechanical properties of the formulations containing SM monomer with increased functionality were comparable with the control, even with more water sorption. The concentration and functionality of the newly synthesized siloxane-methacrylate monomers affected the water miscibility, water sorption and mechanical properties of the adhesives. The experimental adhesives show improved water compatibility compared with the control. The mechanical properties were enhanced with an increase of the functionality of the siloxane-containing monomers. The results provide critical structure/property relationships and important information for future development of durable, versatile siloxane-containing dentin adhesives. Published by Elsevier Ltd.

  15. Density profiles of granular gases studied by molecular dynamics and Brownian bridges

    Science.gov (United States)

    Peñuñuri, F.; Montoya, J. A.; Carvente, O.

    2018-02-01

    Despite the inherent frictional forces and dissipative collisions, confined granular matter can be regarded as a system in a stationary state if we inject energy continuously. Under these conditions, both the density and the granular temperature are, in general, non-monotonic variables along the height of the container. In consequence, an analytical description of a granular system is hard to conceive. Here, by using molecular dynamics simulations, we measure the packing fraction profiles for a vertically vibrating three-dimensional granular system in several gaseous-like stationary states. We show that by using the Brownian bridge concept, the determined packing fraction profiles can be reproduced accurately and give a complete description of the distribution of the particles inside the simulation box.

  16. First density profile measurements using frequency modulation of the continuous wave reflectometry on JETa)

    Science.gov (United States)

    Meneses, L.; Cupido, L.; Sirinelli, A.; Manso, M. E.; Jet-Efds Contributors

    2008-10-01

    We present the main design options and implementation of an X-mode reflectometer developed and successfully installed at JET using an innovative approach. It aims to prove the viability of measuring density profiles with high spatial and temporal resolution using broadband reflectometry operating in long and complex transmission lines. It probes the plasma with magnetic fields between 2.4 and 3.0 T using the V band [~(0-1.4)×1019 m-3]. The first experimental results show the high sensitivity of the diagnostic when measuring changes in the plasma density profile occurring ITER relevant regimes, such as ELMy H-modes. The successful demonstration of this concept motivated the upgrade of the JET frequency modulation of the continuous wave (FMCW) reflectometry diagnostic, to probe both the edge and core. This new system is essential to prove the viability of using the FMCW reflectometry technique to probe the plasma in next step devices, such as ITER, since they share the same waveguide complexity.

  17. Control of the current density profile with lower hybrid current drive on PBX-M

    International Nuclear Information System (INIS)

    Bell, R.E.; Bernabei, S.; Chu, T.K.; Gettelfinger, G.; Greenough, N.; Hatcher, R.; Ignat, D.; Jardin, S.; Kaita, R.; Kaye, S.; Kozub, T.; Kugel, H.; LeBlanc, B.; Okabayashi, M.; Paul, S.; Sauthoff, N.; Sesnic, S.; Sun, Y.; Takahashi, H.; Tighe, W.; Valeo, E.; von Goeler, S.; Jones, S.; Kesner, J.; Luckhardt, S.; Paoletti, F.; Levinton, F.; Timini, F.

    1993-07-01

    Lower hybrid current drive (LHCD) is being explored as a means to control the current density profile on PBX-M with the goal of raising the central safety factor q(O) to values of 1.5-2 to facilitate access to a full-volume second stable regime. Initial experiments have been conducted with up to 400 kW of 4.6 GHz LH power in circular and indented plasmas with modest parameters. A tangential-viewing two-dimensional hard x-ray imaging diagnostic has been used to observe the bremsstrahlung emission from the suprathermal electrons generated during LHCD. Hollow hard x-ray images have indicated off-axis localization of the driven current. A serious obstacle to the control of the current density profile with LHCD is the concomitant generation of MHD activity, which can seriously degrade the confinement of suprathermal electrons. By combining neutral beam injection with LHCD, an MHD-free condition has been obtained where q(O) is raised above 1

  18. Reconstruction and analysis of temperature and density spatial profiles inertial confinement fusion implosion cores

    International Nuclear Information System (INIS)

    Mancini, R. C.

    2007-01-01

    We discuss several methods for the extraction of temperature and density spatial profiles in inertial confinement fusion implosion cores based on the analysis of the x-ray emission from spectroscopic tracers added to the deuterium fuel. The ideas rely on (1) detailed spectral models that take into account collisional-radiative atomic kinetics, Stark broadened line shapes, and radiation transport calculations, (2) the availability of narrow-band, gated pinhole and slit x-ray images, and space-resolved line spectra of the core, and (3) several data analysis and reconstruction methods that include a multi-objective search and optimization technique based on a novel application of Pareto genetic algorithms to plasma spectroscopy. The spectroscopic analysis yields the spatial profiles of temperature and density in the core at the collapse of the implosion, and also the extent of shell material mixing into the core. Results are illustrated with data recorded in implosion experiments driven by the OMEGA and Z facilities

  19. Observation of the skin-like profiles of electron temperature and density of turbulently heated plasmas in the TRIAM-1 tokamak

    International Nuclear Information System (INIS)

    Hiraki, Naoji; Nakamura, Kazuo; Toi, Kazuo; Itoh, Satoshi

    1980-01-01

    The time evolution of electron temperature and density profiles are measured on the turbulent heating experiment in the TRIAM-1 tokamak. The skin-like profiles of electron temperature and density are observed just after the application of the pulsed electric field for turbulent heating. The width of the skin layer of the electron temperature profile is about 1 cm, and agrees well with the theoretical value. The above mentioned skin heating of electrons just after the heating pulse is also spectroscopically confirmed by the remarkable decrease of the volume emission of visible lines which is localized at the outer plasma region. (author)

  20. Observation of the skin-like profiles of electron temperature and density of turbulently heated plasmas in the TRIAM-1 tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Hiraki, N; Nakamura, K; Toi, K; Itoh, S [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

    1980-07-01

    The time evolution of electron temperature and density profiles are measured on the turbulent heating experiment in the TRIAM-1 tokamak. The skin-like profiles of electron temperature and density are observed just after the application of the pulsed electric field for turbulent heating. The width of the skin layer of the electron temperature profile is about 1 cm, and agrees well with the theoretical value. The above mentioned skin heating of electrons just after the heating pulse is also spectroscopically confirmed by the remarkable decrease of the volume emission of visible lines which is localized at the outer plasma region.

  1. Effect of the hardener to epoxy monomer ratio on the water absorption behavior of the DGEBA/TETA epoxy system

    Directory of Open Access Journals (Sweden)

    Ayrton Alef Castanheira Pereira

    2016-02-01

    Full Text Available Abstract The water absorption behavior of the DGEBA/TETA epoxy system was evaluated as a function of the epoxy monomer to amine hardener ratio. Weight gain versus immersion time curves were obtained and the experimental points were fitted using Fickian and Non-Fickian diffusion models. The results obtained showed that for all epoxy monomer to hardener ratios analyzed water diffusion followed non-Fickian behavior. It was possible to correlate the water absorption behavior to the macromolecular structure developed when the epoxy/ hardener ratio was varied. All epoxy/hardener ratios present a two-phase macromolecular structure, composed of regions with high crosslink density and regions with lower crosslinking. Epoxy rich systems have a more open macromolecular structure with a lower fraction of the dense phase than the amine rich systems, which present a more compact two-phase structure.

  2. Self-assembly of actin monomers into long filaments: Brownian Dynamics simulations

    DEFF Research Database (Denmark)

    Shillcock, Julian C.

    2009-01-01

    Brownian dynamics simulations are used to study the dynamical process of self-assembly of actin monomers into long filaments containing up to 1000 actin protomers. In order to overcome the large separation of time scales between the diffusive motion of the freemonomers and the relatively slow....../detachment events. When a single filament is allowed to grow in a bath of constant concentration of free ADP-actin monomers, its growth rate increases linearly with the free monomer concentration in quantitative agreement with in vitro experiments. Theresults also show that the waiting time is governed by...

  3. Investigation of Electron Density Profile in the ionospheric D and E region by Kagoshima rocket experiment

    Science.gov (United States)

    Ashihara, Y.; Ishisaka, K.; Miyake, T.; Okada, T.; Nagano, I.; Abe, T.; Ono, T.

    2007-12-01

    The radio wave propagation characteristic in the lower ionosphere is important because of its effect on commercial radio communication, navigation, and broadcast services. The electron density is of primary interest in this region because the high ion-neutral collision frequencies result in radio wave absorption. In order to investigate the ionization structure in the ionospheric D and E region by using the propagation characteristics of MF-band and LF-band radio waves, S-310-37 and S-520-23 sounding rocket experiments have been carried out at Uchinoura Space Center (USC). S-310-37 sounding rocket was launched at 11:20 LT on January 16, 2007. The apex of rocket trajectory was about 138 km. Then S-520-23 sounding rocket was launched at 19:20 LT on September 2, 2007. The apex was about 279 km. As a common measurement, these sounding rockets measure the fields intensities and the waveform of radio waves from NHK Kumamoto broadcasting station (873kHz, 500kW) and JJY signals from Haganeyama LF radio station (60kHz, 50kW). The approximate electron density profile can be determined from the comparison between these experimental results and propagation characteristics calculated by the full wave method. We will get the most probable electron density profile in the ionosphere. In presentation, we will show the propagation characteristic of LF/MF radio waves measured by two sounding rocket experiments. Then we will discuss the analysis method and the estimated electron density profile in the ionosphere.

  4. Density profiles of the exclusive queuing process

    Science.gov (United States)

    Arita, Chikashi; Schadschneider, Andreas

    2012-12-01

    The exclusive queuing process (EQP) incorporates the exclusion principle into classic queuing models. It is characterized by, in addition to the entrance probability α and exit probability β, a third parameter: the hopping probability p. The EQP can be interpreted as an exclusion process of variable system length. Its phase diagram in the parameter space (α,β) is divided into a convergent phase and a divergent phase by a critical line which consists of a curved part and a straight part. Here we extend previous studies of this phase diagram. We identify subphases in the divergent phase, which can be distinguished by means of the shape of the density profile, and determine the velocity of the system length growth. This is done for EQPs with different update rules (parallel, backward sequential and continuous time). We also investigate the dynamics of the system length and the number of customers on the critical line. They are diffusive or subdiffusive with non-universal exponents that also depend on the update rules.

  5. Photokopolimerisasi monomer akrilat degan kulit kras sapi

    Directory of Open Access Journals (Sweden)

    Dwi Wahini Nurhajati

    1997-06-01

    Full Text Available The research on photocopolymerization of acrylate monomer with cow crust hide had object to observe the resulted copolymer onto cow crust hide. Crust hides, saturated with aqueous emulsions containing 25 wt % of n-butyl acrylate (n-BA or tripropylene glycol diacrylate (TPGDA were irradiated by cobalt – 60 gamma rays with doses ranges from 5 to 25 kGy. The irradiated hides were washed with water, dried in air and extracted in soxhlet apparatus for 48 hours to remove homopolymer. The highest yield of photocopolymerization of n – butyl acrylate monomer with crust hides was found 17,7878% at dose 25 kGy, and for photocopolymerization of tripropylene glycol diacrylate with crust hides was found 39,4245% at dose 20 kGy.

  6. Radical copolymerization in homogenous medium and emulsion system monomers acrylonitrile/styrene

    Directory of Open Access Journals (Sweden)

    Boussehel H.

    2013-09-01

    Full Text Available This study examines the radical copolymerization in homogeneous and emulsion of the monomer system acrylonitrile/styrene. These copolymers are of great interest to the plastics industry, because they combine the good mechanical properties and implementation provided by the styrene units in the very high solvent resistance and extreme gas impermeability provided by the acrylonitrile units. The properties of a copolymer are directly related to its composition and distribution of monomer units in its macromolecular chains. Based on the reports of the couple reactivity's of monomers (AN/S found in the literature, the objective of the work is to provide theoretical simulation (by analytical and numerical integration of the equation of copolymerization: The kinetics of the reaction copolymerization of AN/S in a homogeneous medium and emulsion (drift composition, azeotropic and the microstructure (distribution of monomer sequences and the glass transition property of the macromolecular chains instant formed throughout the copolymerization reaction.

  7. On-line measurement of residual monomer during polymerisation of acrylamide using ultrasonics

    International Nuclear Information System (INIS)

    Ponraju, D.; Sebastian, Letha; Viswanathan, S.; Natarajan, A.; Palanichamy, P.; Jayakumar, T.; Baldev Raj

    1996-01-01

    An ultrasonic technique for the estimation of residual acrylamide monomer during the polymerization of aqueous acrylamide solution has been investigated. Polyacrylamide gel medium serves as a sensitive medium for detection and dosimetry of fast and thermal neutrons. This technique is based on the fact that the velocity of ultrasonic wave increases with the increase in elasticity due to polymerization. The percentage of residual acrylamide monomer is estimated using ultraviolet spectrophotometric analysis. The ultrasonic velocity is correlated with the residual monomer concentration

  8. The radiation grafting of vinyl monomers to cotton fabrics

    International Nuclear Information System (INIS)

    Shiraishi, N.; Williams, J.L.; Stannett, V.

    1982-01-01

    Cobalt 60 γ and electron beam radiation were used to graft diethylphosphatoethyl methacrylate, pure and in 90:10 methanol solution, to cotton cloth. This monomer, with an 11.64% phosphorus content, was especially developed by the Scott Paper Co. to develop fire retardancy. A simple pad and squeeze application followed by direct irradiation under a nitrogen atmosphere was used. Although excess monomer could be removed by washing with water, no solvent for the polymer was found so only the total 'add-ons' could be measured. With 60 Co irradiation, total polymerization was obtained with more than 1 Mrad but with electron beam irradiation only about 50% conversion was obtained even with 10 Mrad. No acceleration in the rates could be achieved with the viscous pure monomer as opposed to in solution. Yields adequate to impart reasonable fire retardancy could, however, be obtained with about 3 Mrad with electrons. No noticeable degradation of the polymer occurred at the doses used. (author)

  9. Determination of density profiles of unevenly compressed wood of Po­pu­lus tremula using the X – RAY DENSE – LAB laboratory device

    Directory of Open Access Journals (Sweden)

    Aleš Dejmal

    2009-01-01

    Full Text Available The paper deals with the measuring of the density profile of unevenly pressed wood of European aspen (Populus tremula L.. The main aim of the work is to examine in an experimental way the possibilities of using the X – RAY DENSE – LAB laboratory equipment designed for the determination of density profiles of agglomerated and plied large-area materials. The work uses the X – RAY DENSE – LAB equipment to determine the density profile of the cross-section of unevenly pressed aspen wood, plasticized hydrothermically, without the presence of chemical substances. The work also presents calculations of the level of compression/densification in dependence on the density and it describes the factors that can influence the density profile of compressed/densified wood; at the same time, it presents the possible ways to determine the density profile in the cross-section. Further, it includes the creation of the methodology for sample preparation so that the results do not get distorted during measuring. It describes the preparation of sample pieces, the orientation of the anatomic structure, the methodology of pressing, air conditioning, sample preparation, their measuring and analysis. The paper also describes the theory and the principles of measuring with use of X – RAY DENSE – LAB and its calibration. The paper analyses the obtained results of density profiles and searches for and describes the causes of the uneven distribution of the density in the cross-section. It concludes by summarizing the results and recommending the procedure for future measuring.

  10. Elution of Monomers from Provisional Composite Materials

    Directory of Open Access Journals (Sweden)

    Simon Daniel Schulz

    2015-01-01

    Full Text Available The aim of this study was to evaluate the elution of substances from different materials used for the manufacturing of temporary indirect restorations, after storage in saliva and ethanol 75%. 10 samples of three chemically cured materials (Protemp 3 Garant, Systemp.c&b, and Trim and one light-cured material (Clip F were stored in saliva and ethanol 75% for 24 h, 7, and days 28 days. From the storage media at each time period, samples were prepared and analysed by LC-MS/MS, in order to access the elution of monomers. The results differed among the materials (P ≤ 0.05. No monomers were detected in the samples of Protemp 3 Garant and Clip F. Substances were detected only in ethanol samples of Systemp.c&b and Trim. The amount of BisGMA, TEGDMA, and UDMA 2 released from Systemp.c&b was higher compared to Trim. Storage time affected the release of substances (P ≤ 0.05. The highest release was observed within the first 24 h. It can be concluded that provisional resin composite materials do not show high release of monomers and this release is material dependent. However, the detection of additional peaks during the analysis, suggesting the formation of by-products of the eluted substances, may not be in favour of these materials with respect to their toxicity.

  11. Radiation curing of mixtures of diallylphthalate prepolymer and vinyl monomer, 9

    International Nuclear Information System (INIS)

    Gotoda, Masao; Kitada, Yoshinori.

    1975-01-01

    Radiation curing, mainly by electron beams was studied with mixtures of low molecular weight diallylphthalate prepolymer (DAPsub(p).L) and vinyl monomers with special reference to their workability. Among the vinyl monomers, acrylonitrile gave a solution of low viscosity and methyl acrylate gave a solution of low dose curing. Radiation curing of DAPsub(p).L/vinyl monomer mixtures impregnated in wood was also tried. To obtain uniform wood-polymer composites, γ-irradiation after impregnation at 10 kg/cm 2 was found to be required for thick plate (110 mm), while electron beam irradiation after impregnation at normal pressure was sufficient for thin plate. (author)

  12. Effect of monomer composition on the properties of high temperature polymer concretes

    Energy Technology Data Exchange (ETDEWEB)

    Zeldin, A.; Kukacka, L.E.; Carciello, N.

    1980-01-01

    The effects of organic monomer composition on the thermomechanical properties of polymer concrete (PC) containing sand-cement mixtures as an agregate filler were investigated. The effects of various monomer mixtures on compressive strength and hydrolytic stability are discussed. Composites were fabricated in the same way as ordinary concrete, with monomer solutions of various compositions and concentrations used to bind the sand-cement mixture. The compressive strengths of th composites before and after exposure to air and to brine solutions at 240/sup 0/C are discussed.

  13. Topside ionospheric vertical electron density profile reconstruction using GPS and ionosonde data: possibilities for South Africa

    Directory of Open Access Journals (Sweden)

    P. Sibanda

    2011-02-01

    Full Text Available Successful empirical modeling of the topside ionosphere relies on the availability of good quality measured data. The Alouette, ISIS and Intercosmos-19 satellite missions provided large amounts of topside sounder data, but with limited coverage of relevant geophysical conditions (e.g., geographic location, diurnal, seasonal and solar activity by each individual mission. Recently, methods for inferring the electron density distribution in the topside ionosphere from Global Positioning System (GPS-based total electron content (TEC measurements have been developed. This study is focused on the modeling efforts in South Africa and presents the implementation of a technique for reconstructing the topside ionospheric electron density (Ne using a combination of GPS-TEC and ionosonde measurements and empirically obtained Upper Transition Height (UTH. The technique produces reasonable profiles as determined by the global models already in operation. With the added advantage that the constructed profiles are tied to reliable measured GPS-TEC and the empirically determined upper transition height, the technique offers a higher level of confidence in the resulting Ne profiles.

  14. TIDAL STIRRING OF SATELLITES WITH SHALLOW DENSITY PROFILES PREVENTS THEM FROM BEING TOO BIG TO FAIL

    Energy Technology Data Exchange (ETDEWEB)

    Tomozeiu, Mihai; Mayer, Lucio [Institute for Computational Science, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland); Quinn, Thomas, E-mail: mihai@physik.uzh.ch [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195 (United States)

    2016-08-10

    The “too big to fail” problem is revisited by studying the tidal evolution of populations of dwarf satellites with different density profiles. The high-resolution cosmological ΛCDM “ErisMod” set of simulations is used. These simulations can model both the stellar and dark matter components of the satellites, and their evolution under the action of the tides of a Milky Way (MW)-sized host halo at a force resolution better than 10 pc. The stronger tidal mass loss and re-shaping of the mass distribution induced in satellites with γ = 0.6 dark matter density distributions, as those resulting from the effect of feedback in hydrodynamical simulations of dwarf galaxy formation, are sufficient to bring the circular velocity profiles in agreement with the kinematics of MW’s dSphs. In contrast, in simulations in which the satellites retain cusps at z = 0 there are several “massive failures” with circular velocities in excess of the observational constraints. Various sources of deviations in the conventionally adopted relation between the circular velocity at the half-light radius and the one-dimensional line of sight velocity dispersions are found. Such deviations are caused by the response of circular velocity profiles to tidal effects, which also varies depending on the initially assumed inner density profile and by the complexity of the stellar kinematics, which include residual rotation and anisotropy. In addition, tidal effects naturally induce large deviations in the stellar mass–halo mass relation for halo masses below 10{sup 9} M {sub ⊙}, preventing any reliable application of the abundance matching technique to dwarf galaxy satellites.

  15. Perturbation of the Monomer-Monomer Interfaces of the Benzoylformate Decarboxylase Tetramer

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, Forest H.; Rogers, Megan P.; Paul, Lake N.; McLeish, Michael J. [IUPUI; (Purdue)

    2014-08-14

    The X-ray structure of benzoylformate decarboxylase (BFDC) from Pseudomonas putida ATCC 12633 shows it to be a tetramer. This was believed to be typical of all thiamin diphosphate-dependent decarboxylases until recently when the structure of KdcA, a branched-chain 2-keto acid decarboxylase from Lactococcus lactis, showed it to be a homodimer. This lent credence to earlier unfolding experiments on pyruvate decarboxylase from Saccharomyces cerevisiae that indicated that it might be active as a dimer. To investigate this possibility in BFDC, we sought to shift the equilibrium toward dimer formation. Point mutations were made in the noncatalytic monomer–monomer interfaces, but these had a minimal effect on both tetramer formation and catalytic activity. Subsequently, the R141E/Y288A/A306F variant was shown by analytical ultracentrifugation to be partially dimeric. It was also found to be catalytically inactive. Further experiments revealed that just two mutations, R141E and A306F, were sufficient to markedly alter the dimer–tetramer equilibrium and to provide an ~450-fold decrease in kcat. Equilibrium denaturation studies suggested that the residual activity was possibly due to the presence of residual tetramer. The structures of the R141E and A306F variants, determined to <1.5 Å resolution, hinted that disruption of the monomer interfaces will be accompanied by movement of a loop containing Leu109 and Leu110. As these residues contribute to the hydrophobicity of the active site and the correct positioning of the substrate, it seems that tetramer formation may well be critical to the catalytic activity of BFDC.

  16. In situ polymerization of monomers for polyphenylquinoxaline/graphite

    Science.gov (United States)

    Serafini, T. T.; Delvigs, P.; Vannucci, R. D.

    1973-01-01

    Methods currently used to prepare fiber reinforced, high temperature resistant polyphenylquinoxaline (PPQ) composites employ extremely viscous, low solids content solutions of high molecular weight PPQ polymers. An improved approach, described in this report, consists of impregnating the fiber with a solution of the appropriate monomers instead of a solution of previously synthesized high molecular weight polymer. Polymerization of the monomers occurs in situ on the fiber during the solvent removal and curing stages. The in situ polymerization approach greatly simplifies the fabrication of PPQ graphite fiber composites. The use of low viscosity monomeric type solutions facilitates fiber wetting, permits a high solids content, and eliminates the need for prior polymer synthesis.

  17. A comment on water’s structure using monomer fraction data and theories

    DEFF Research Database (Denmark)

    Liang, Xiaodong; Maribo-Mogensen, Bjørn; Tsivintzelis, Ioannis

    2016-01-01

    Monomer fraction data for water (and other compounds) can provide useful information about their structure and can be used in “advanced” equations of state, which account explicitly for association phenomena. Recent findings about the performance of association theories in representing the monomer...... fraction of water are reviewed. Three such theories are considered and all of them perform qualitatively similar. They can all represent phase equilibria for water solutions qualitatively well but with parameters which are not in good agreement with Luck’s famous monomer fraction data. While this could set...... the theoretical basis of these theories in doubt, we also show in this work that the findings with these association models are in agreement with a recently presented theory which links monomer fraction to dielectric constants. This new theory, like the three thermodynamic models, predicts more hydrogen bonding...

  18. Vogel-Fulcher dependence of relaxation rates in a nematic monomer and elastomer

    Science.gov (United States)

    Shenoy, D.; Filippov, S.; Aliev, F.; Keller, P.; Thomsen, D.; Ratna, B.

    2000-12-01

    Dielectric relaxation spectroscopy is used to study the relaxation processes in a nematic monomer and the corresponding cross-linked polymer nematic liquid crystal (elastomer). In the frequency window 10 mHz to 2 GHz the monomer liquid crystal shows a single relaxation whereas the polymer exhibits three relaxation processes, two of which are quantitatively analyzed. The temperature dependence of relaxation times in both the monomer and polymer follows a Vogel-Fulcher behavior. The relaxation processes are identified with specific molecular motions and activation energies are calculated in a linear approximation for comparison with literature data.

  19. Measurement of the density profile of pure and seeded molecular beams by femtosecond ion imaging

    NARCIS (Netherlands)

    Meng, C.; Janssen, M.H.M.

    2015-01-01

    Here, we report on femtosecond ion imaging experiments to measure the density profile of a pulsed supersonic molecular beam. Ion images are measured for both a molecular beam and bulk gas under identical experimental conditions via femtosecond multiphoton ionization of Xe atoms. We report the

  20. X mode reflectometry for edge density profile measurements on Tore Supra

    International Nuclear Information System (INIS)

    Clairet, F.; Bottereau, C.; Chareau, J.M.; Paume, M.; Sabot, R.

    1999-01-01

    X mode heterodyne reflectometry associated with fast sweep capabilities demonstrates very precise measurement on Tore Supra and a high sensitivity (∼10 17 m -3 ) to density variations. Very good agreement with Thomson scattering measurement is observed. Fluctuations of the radial positions of the profile are no more than ± 0.5 cm. However, edge magnetic field ripple can be a concern since it is not easy to stand precisely for the wave trajectory into the plasma and for the toroidal position of the cutoff layer; nevertheless if the error can be estimated to be less than than 3 cm in the position of the whole profile, addition work is needed combining 3-D ray tracing and different antenna systems. Additional LH heating generates an ECE noise in the same frequency range of the reflectometer and is detected. This emission throughout the plasma is fortunately stopped by the upper X mode cutoff and is also reabsorbed by the electron cyclotron resonance. But at the very edge, due to a misalignment of the antenna to the plasma magnetic field and the low optical thickness of the plasma, the first cutoff frequency, i.e. the profile initialization, may be determined less precisely. (authors)

  1. Radiation power profiles and density limit with a divertor in the W7-AS stellarator

    International Nuclear Information System (INIS)

    Giannone, L.; Burhenn, R.; McCormick, K.; Brakel, R.; Feng, Y.; Grigull, P.; Igitkhanov, Y.

    2002-01-01

    The addition of a divertor into the W7-AS stellarator has allowed access to a high density regime where the radiation profiles reach a steady state. In earlier limiter discharges, the plasma suffered a radiative collapse at high densities. In contrast to limiter experiments, where the impurity confinement time measured by Al laser blow-off increased with increasing line integrated density, in divertor discharges, above a density threshold, the impurity confinement time decreased with increasing line integrated density. The observation that the divertor plasma radiates mainly at the plasma edge rather than the plasma centre is a further indication that changes to the impurity transport coefficients at these high densities are the basis for the achievement of steady state discharges in the divertor configuration of W7-AS. The maximum line integrated density reached with a divertor is compared to that reached with a limiter. The previously derived scaling law for the density limit with a limiter shows that the achieved densities do not exceed those predicted when the higher deposited power is taken into account. In a divertor the radiated power is located at the plasma edge and increasing the density, cooling the plasma edge and radiating sufficient power to cause plasma detachment determines the density limit. (author)

  2. The difference of acrylic resin residual monomer levels with various polymerization method

    Directory of Open Access Journals (Sweden)

    Sherman Salim

    2011-12-01

    Full Text Available Background: After polymerization process, heat cured acrylic resin denture base actually still contains residual monomers that can become potential irritants later in oral cavity. Polymerization process is essential to obtain acrylic resin which can meet the requirements of the biocompatible and good physical properties. To meet the requirements, there are several methods of polymerization process used. Purpose: The purpose of this study was to determine the differences of the residual monomer levels of acrylic resin processed by various polymerization methods. Methods: Acrylic resin powder and liquid were mixed based on the rules of factory, and sample was made with size of 30 mm × 50 mm × 3 mm and then polymerized by using microwave at 70° C for 24 hours based on the methods of Japan Industrial Standard (JIS. Each group of samples was cut with weight of ± 0.2 g, dissolved in 5 ml of methyl ethyl ketone in test tubes, and then stored at ± 5° C for four days. Residual monomer level was conducted by using gas chromatograph mass spectrometer. Data obtained were then analyzed by using One-Way ANOVA test with p < 0.05. Results: After the level of polymerizing residual monomer with JIS method was compared to that at 70° C for 24 hours using microwave, it is known that there were significant differences (p < 0.05. Conclusion: The highest level of residual monomer of acrylic resin was that polymerized at 70° C for 24 hours.Latar belakang: Basis gigi tiruan yang berbahan dasar resin akrilik jenis heat cured setelah proses polimerisasi selesai masih mengandung monomer sisa yang berpotensi sebagai bahan iritan dalam rongga mulut. Proses polimerisasi sangat penting untuk mendapatkan resin akrilik yang memenuhi persyaratan biokompatibilitas dan fisik yang baik. Untuk persyaratan tersebut digunakan berbagai macam proses polimerisasi. Tujuan: Penelitian ini bertujuan untuk menentukan kadar monomer sisa resin akrilik yang diproses dengan metode

  3. Effect of food simulating liquids on release of monomers from two dental resin composites

    Directory of Open Access Journals (Sweden)

    Ghavam M

    2010-06-01

    Full Text Available "nBackground and Aims: The elution of residual monomers from cured dental composites to oral cavity has a harmful effect on human health and can affect their clinical durability. The purpose of this study was to evaluate the amount of eluted monomers (Bis-GMA, TEGDMA, UDMA from two types of composites (Gradia and P60 after exposure to food simulating liquids such as ethanol (25, 50, 75 % and heptane 50 % for 24 hours and 7 days. "nMaterials and Methods: Forty specimens of each composite were prepared. Equal numbers of each composite were immersed in tubes containing 2cc volumes of 25, 50, 75 % ethanole and 50 % heptane. The amount of eluted monomers in standard condition such as Bis-GMA, TEGDMA and UDMA was measured by GC/MS (Gas Chromatography/Mass Spectroscopy and results were statistically analysed by three way and one way ANOVA. P<0.05 was considered as the level of significancy. "nResults: The results showed that Gradia released more TEGDMA than P60. In assessing the effect of environment, the result showed that ethanol caused releasing monomers more than heptane and the concentration rate of 75 % ethanole resulted in most releasing of monomers. In assessing the effect of time, the observation showed that more monomers were released 7 days compared to 24 hours. Bis-GMA and UDMA were not detected in any solutions in these conditions. "nConclusion: Ethanole caused more release of monomers than heptane and 75 % ethanole released the most amount of monomers. Gradia released more amount of TEGDMA than P60.

  4. Valve seat pores sealed with thermosetting monomer

    Science.gov (United States)

    Olmore, A. B.

    1966-01-01

    Hard anodic coating provides a smooth wear resistant value seating surface on a cast aluminum alloy valve body. Vacuum impregnation with a thermosetting monomer, diallyl phthalate, seals the pores on the coating to prevent galvanic corrosion.

  5. Density profiles and collective excitations of a trapped two-component Fermi vapour

    International Nuclear Information System (INIS)

    Amoruso, M.; Meccoli, I.; Minguzzi, A.; Tosi, M.P.

    1999-08-01

    We discuss the ground state and the small-amplitude excitations of a degenerate vapour of fermionic atoms placed in two hyperfine states inside a spherical harmonic trap. An equations-of-motion approach is set up to discuss the hydrodynamic dissipation processes from the interactions between the two components of the fluid beyond mean-field theory and to emphasize analogies with spin dynamics and spin diffusion in a homogeneous Fermi liquid. The conditions for the establishment of a collisional regime via scattering against cold-atom impurities are analyzed. The equilibrium density profiles are then calculated for a two-component vapour of 40 K atoms: they are little modified by the interactions for presently relevant values of the system parameters, but spatial separation of the two components will spontaneously arise as the number of atoms in the trap is increased. The eigenmodes of collective oscillation in both the total particle number density and the concentration density are evaluated analytically in the special case of a symmetric two-component vapour in the collisional regime. The dispersion relation of the surface modes for the total particle density reduces in this case to that of a one-component Fermi vapour, whereas the frequencies of all other modes are shifted by the interactions. (author)

  6. Growth of monodisperse mesoscopic metal-oxide colloids under constant monomer supply

    Science.gov (United States)

    Nozawa, Koh; Delville, Marie-Hélène; Ushiki, Hideharu; Panizza, Pascal; Delville, Jean-Pierre

    2005-07-01

    In closed systems, control over the size of monodisperse metal-oxide colloids is generally limited to submicrometric dimensions. To overcome this difficulty, we explore the formation and growth of silica particles under constant monomer supply. The monomer source is externally driven by the progressive addition into the system of one of the precursors. Monodisperse spherical particles are produced up to a mesoscopic size. We analyze their growth versus the monomer addition rate at different temperatures. Our results show that in the presence of a continuous monomer addition, growth is limited by diffusion over the investigated temporal window. Using the temperature variation of the growth rate, we prove that rescaling leads to a data reduction onto a single master curve. Contrary to the growth process, the final particle’s size reached after the end of the reagent supply strongly depends on the addition rate. The variation of the final particle size versus addition rate can be deduced from an analogy with crystal formation in jet precipitation. Within this framework, and using the temperature dependences of both the particle growth law and the final size, we determine the value of the molecular heat of dissolution associated to the silica solubility. These observations support the fact that classical theories of phase-ordering dynamics can be extended to the synthesis of inorganic particles. The emergence of a master behavior in the presence of continuous monomer addition also suggests the extension of these theories to open systems.

  7. Anomalous plasma heating induced by modulation of the current-density profile

    International Nuclear Information System (INIS)

    Lopes Cardozo, N.J.

    1985-05-01

    The usual plasma heating in a tokamak needs additional heating to reach ignition temperature (approx. 10 8 K). The method used in the TORTUR III experiment is to induce anomalous plasma resistivity by applying a short (10 microseconds) high-voltage pulse. A sharp rise of the plasma temperature is found almost simultaneously, but this effect, though considerable, is too short-lived to be of interest for a thermonuclear chain reaction. A second pulse gives a second rise of temperature, but this time a slow one, extending over several milliseconds. The mechanism of this delayed heating and the reservoir within the plasma supplying the energy are subjects of investigation in the TORTUR III experiments. Some conclusions concerning the plasma heating mechanism are presented. The conclusion is reached that the application of the high-voltage pulse results in a modulation of the current-density profile: the (normally already peaked) profile sharpens, the current concentrates in the centre of the plasma column. This is a non-equilibrium situation. It relaxes to the noraml current distribution within approximately 2 milliseconds. As long as this relaxation process is not finished, the dissipation is on an enhanced level and anomalous plasma heating is observed. Many plasma parameters are surveyed and evaluated: temperature (both of the ions and the electrons), density, emission spectrum (from microwaves to hard X-rays) and the fluctuation spectrum. Main subject of this report is the measurement and interpretation of the X-rays of the emission spectrum. Experimental results are presented and discussed

  8. Density profiles in the Scrape-Off Layer interpreted through filament dynamics

    Science.gov (United States)

    Militello, Fulvio

    2017-10-01

    We developed a new theoretical framework to clarify the relation between radial Scrape-Off Layer density profiles and the fluctuations that generate them. The framework provides an interpretation of the experimental features of the profiles and of the turbulence statistics on the basis of simple properties of the filaments, such as their radial motion and their draining towards the divertor. L-mode and inter-ELM filaments are described as a Poisson process in which each event is independent and modelled with a wave function of amplitude and width statistically distributed according to experimental observations and evolving according to fluid equations. We will rigorously show that radially accelerating filaments, less efficient parallel exhaust and also a statistical distribution of their radial velocity can contribute to induce flatter profiles in the far SOL and therefore enhance plasma-wall interactions. A quite general result of our analysis is the resiliency of this non-exponential nature of the profiles and the increase of the relative fluctuation amplitude towards the wall, as experimentally observed. According to the framework, profile broadening at high fueling rates can be caused by interactions with neutrals (e.g. charge exchange) in the divertor or by a significant radial acceleration of the filaments. The framework assumptions were tested with 3D numerical simulations of seeded SOL filaments based on a two fluid model. In particular, filaments interact through the electrostatic field they generate only when they are in close proximity (separation comparable to their width in the drift plane), thus justifying our independence hypothesis. In addition, we will discuss how isolated filament motion responds to variations in the plasma conditions, and specifically divertor conditions. Finally, using the theoretical framework we will reproduce and interpret experimental results obtained on JET, MAST and HL-2A.

  9. The binding of glucose to yeast hexokinase monomers is independent of ionic strength.

    Science.gov (United States)

    Mayes, E L; Hoggett, J G; Kellett, G L

    1982-05-01

    Hoggett & Kellett [Eur. J. Biochem. 66, 65-77 (1976)] have reported that the binding of glucose to the monomer of hexokinase PII isoenzyme is independent of ionic strength, in contrast to the subsequent claim of Feldman & Kramp [Biochemistry 17, 1541-1547 (1978)] that the binding is strongly dependent on ionic strength. Since measurements with native hexokinase P forms are complicated by the fact that the enzyme exists in a monomer-dimer association-dissociation equilibrium, we have now studied the binding of glucose to the proteolytically-modified S forms which are monomeric. At pH 8.5, the affinity of glucose for both SI and SII monomers is independent of salt concentration over the range of KCl concentrations 0-1.0 mol . dm-3 and is in good agreement with that of the corresponding P forms in both low and high salt. These observations confirm that the binding of glucose to hexokinase P monomers is independent of ionic strength and that the affinity of glucose for the hexokinase PII monomer is about an order of magnitude greater than that for the dimer.

  10. Characterization of Electron Temperature and Density Profiles of Plasmas Produced by Nike KrF Laser for Laser Plasma Instability (LPI) Research

    Science.gov (United States)

    Oh, Jaechul; Weaver, J. L.; Phillips, L.; Obenschain, S. P.; Schmitt, A. J.; Kehne, D. M.; Chan, L.-Y.; Serlin, V.

    2011-10-01

    Previous experiments with Nike KrF laser (λ = 248 nm , Δν ~ 1 THz) observed LPI signatures near quarter critical density (nc / 4) in CH plasmas, however, detailed measurement of the temperature (Te) and density (ne) profiles was missing. The current Nike LPI campaign will perform experimental determination of the plasma profiles. A side-on grid imaging refractometer (GIR) is the main diagnostic to resolve Te and ne in space taking 2D snapshots of probe laser (λ = 266 nm , Δt = 8 psec) beamlets (50 μm spacing) refracted by the plasma at laser peak time. Ray tracing of the beamlets through hydrodynamically simulated (FASTRAD3D) plasma profiles estimates the refractometer may access densities up to ~ 0 . 2nc . With the measured Te and ne profiles in the plasma corona, we will discuss analysis of light data radiated from the plasmas in spectral ranges relevant to two plasmon decay and convective Raman instabilities. Validity of the (Te ,ne) data will also be discussed for the thermal transport study. Work supported by DoE/NNSA and ONR and performed at NRL.

  11. Density profile of nitrogen in cylindrical pores of MCM-41

    Science.gov (United States)

    Soper, Alan K.; Bowron, Daniel T.

    2017-09-01

    A straightforward approach using radiation scattering (X-ray or neutron) combined with atomistic modelling is used to accurately assess the pore dimensions in the porous silica, MCM-41. The method is used to calculate the density profile of nitrogen absorbed in this material at a variety of fractional pressures, p/p0, where p0 is the saturated vapour pressure, up to p/p0 = 0.36 at T = 87 K in the present instance. At this pressure two distinct layers of liquid nitrogen occur on the silica surface, with a relatively sharp gas-liquid interface. It is suggested surface tension effects at this interface strongly influence the growth of further layers.

  12. Structure of human insulin monomer in water/acetonitrile solution

    International Nuclear Information System (INIS)

    Bocian, Wojciech; Sitkowski, Jerzy; Bednarek, Elzbieta; Tarnowska, Anna; Kawecki, Robert; Kozerski, Lech

    2008-01-01

    Here we present evidence that in water/acetonitrile solvent detailed structural and dynamic information can be obtained for important proteins that are naturally present as oligomers under native conditions. An NMR-derived human insulin monomer structure in H 2 O/CD 3 CN, 65/35 vol%, pH 3.6 is presented and compared with the available X-ray structure of a monomer that forms part of a hexamer (Acta Crystallogr. 2003 Sec. D59, 474) and with NMR structures in water and organic cosolvent. Detailed analysis using PFGSE NMR, temperature-dependent NMR, dilution experiments and CSI proves that the structure is monomeric in the concentration and temperature ranges 0.1-3 mM and 10-30 deg. C, respectively. The presence of long-range interstrand NOEs, as found in the crystal structure of the monomer, provides the evidence for conservation of the tertiary structure. Starting from structures calculated by the program CYANA, two different molecular dynamics simulated annealing refinement protocols were applied, either using the program AMBER in vacuum (AMBER V C), or including a generalized Born solvent model (AMBER G B)

  13. Formulation of detector response function to calculate the power density profiles using in-core neutron detectors

    International Nuclear Information System (INIS)

    Ahmed, S. A.; Peter, J. K.; Semmler, W.; Shultis, J. K.

    2007-01-01

    By measuring neutron fluxes at different locations throughout a core, it's possible to derive the power-density profile P k (W cm - 3), at an axial depth z of fuel rod k. Micro-pocket fission detectors (MPFD) have been fabricated to perform such in-core neutron flux measurements. The purpose of this study is to develop a mathematical model to obtain axial power density distributions in the fuel rods from the in-core responses of the MPFDs

  14. Angular filter refractometry analysis using simulated annealing [An improved method for characterizing plasma density profiles using angular filter refractometry

    International Nuclear Information System (INIS)

    Angland, P.; Haberberger, D.; Ivancic, S. T.; Froula, D. H.

    2017-01-01

    Here, a new method of analysis for angular filter refractometry images was developed to characterize laser-produced, long-scale-length plasmas using an annealing algorithm to iterative converge upon a solution. Angular filter refractometry (AFR) is a novel technique used to characterize the density pro files of laser-produced, long-scale-length plasmas. A synthetic AFR image is constructed by a user-defined density profile described by eight parameters, and the algorithm systematically alters the parameters until the comparison is optimized. The optimization and statistical uncertainty calculation is based on a minimization of the χ2 test statistic. The algorithm was successfully applied to experimental data of plasma expanding from a flat, laser-irradiated target, resulting in average uncertainty in the density profile of 5-10% in the region of interest.

  15. Design of an O-mode frequency modulated reflectometry system for the measurement of Alborz Tokamak plasma density profile

    Energy Technology Data Exchange (ETDEWEB)

    Koohestani, Saeideh [Department of Energy Engineering and physics, Amirkabir University of Technology, Tehran, 15875-4413, Islamic Republic of Iran (Iran, Islamic Republic of); Amrollahi, Reza, E-mail: amrollahi@aut.ac.ir [Department of Energy Engineering and physics, Amirkabir University of Technology, Tehran, 15875-4413, Islamic Republic of Iran (Iran, Islamic Republic of); Moradi, Gholamreza [Department of Electrical Engineering, Amirkabir University of Technology, Tehran, 15875-4413, Islamic Republic of Iran (Iran, Islamic Republic of)

    2016-12-15

    Reflectometry is a common method for plasma diagnostic, in which microwaves are launched into the plasma and reflected at the critical surfaces. Comparing the reflected microwave signals with the launched waves would give rise to the plasma density profiles. In the present study, an ordinary mode (O-mode) frequency modulation (FM) reflectometry system has been designed for the electron density profile measurement of the Alborz Tokamak plasma. This system has been considered to operate at K-band (18–26.5 GHz) frequency range and scan the frequency band between 18 to 26 GHz in 40 μS. The density profile from major radius r = 47.9–51.55 cm can be measured in Alborz Tokamak plasma. Based on the Alborz Tokamak operational conditions, the characteristic frequencies, and some dimensional limitations, all parts of reflectometer have been designed so that an appropriate efficiency with minimum attenuation, especially in transmitting/receiving system would be achieved. A dual antenna and an oversized waveguide of X-band (8–12 GHz) for transmitting and receiving purposes and a balanced detector for absolute phase determination have been utilized. The details of the Alborz Tokamak FM reflectometry components focusing on the antenna and waveguide design and mounting are described in this paper. Additionally, the procedure of plasma profile reconstruction using the system output signal is discussed. This system uses signal phase shift to determine the position of the cutoff layer.

  16. pKa value and buffering capacity of acidic monomers commonly used in self-etching primers.

    Science.gov (United States)

    Salz, Ulrich; Mücke, Angela; Zimmermann, Jörg; Tay, Franklin R; Pashley, David H

    2006-06-01

    The aim of this investigation was to characterize acidic monomers used in self-etching primers/adhesives by determination of their pKa values and by calculation of their calcium dissolving capacity in comparison with phosphoric and hydrochloric acid. The following acidic monomers were included in this study: 4-methacryloyloxyethyl trimellitate anhydride (4-META), 10-methacryloyloxydecyl dihydrogen phosphate (MDP), dimethacryloyloxyethyl hydrogen phosphate (di-HEMA-phosphate), ethyl 2-[4-(dihydroxyphosphoryl)-2-oxabutyl]acrylate (EAEPA), 2-[4-(dihydroxyphosphoryl)-2-ox-abutyl]acrylic acid (HAEPA), and 2,4,6 trimethylphenyl 2-[4-(dihydroxyphosphoryl)-2-oxabutyl]acrylate (MAEPA). The pKa values were obtained by titration with 0.1 mol/l NaOH in aqueous solution. The inflection points of the resulting potentiometric titration curve were determined as pKa values. In the case of the sparingly water-soluble acidic monomers MAEPA and 4-META, the co-solvent method using different water/ethanol ratios for MAEPA or water/acetone ratios for 4-META was used. The dissolving capacity of each acidic monomer is defined as the amount of hydroxyapatite (HA) dissolved by 1 g of acid. For each monomer, the HA dissolving capacity was calculated bythe corresponding pKa value and the molecular weight. To confirm the calculated dissolving capacities, increasing amounts of HA powder (100 mg portions) were slowly added to 15 mmol/l aqueous solutions of the monomers to determine how much HA could be dissolved in the acidic solutions. For all the investigated acidic monomers, pKal values between 1.7 to 2.5 were observed. The pKa2 values for the phosphate/phosphonate derivatives are between 7.0 and 7.3, and are comparable to phosphoric acid. For dicarboxylic acid derivatives, the pKa2 values are in the range of 4.2 to 4.5. Due to their comparable molecular weights and pKal values, the three tested acids di-HEMA phosphate, MDP and 4-META all possess comparable dissolving capacities for HA (ie, 0

  17. Redesign of the monomer-monomer interface of Cre recombinase yields an obligate heterotetrameric complex.

    Science.gov (United States)

    Zhang, Chi; Myers, Connie A; Qi, Zongtai; Mitra, Robi D; Corbo, Joseph C; Havranek, James J

    2015-10-15

    Cre recombinase catalyzes the cleavage and religation of DNA at loxP sites. The enzyme is a homotetramer in its functional state, and the symmetry of the protein complex enforces a pseudo-palindromic symmetry upon the loxP sequence. The Cre-lox system is a powerful tool for many researchers. However, broader application of the system is limited by the fixed sequence preferences of Cre, which are determined by both the direct DNA contacts and the homotetrameric arrangement of the Cre monomers. As a first step toward achieving recombination at arbitrary asymmetric target sites, we have broken the symmetry of the Cre tetramer assembly. Using a combination of computational and rational protein design, we have engineered an alternative interface between Cre monomers that is functional yet incompatible with the wild-type interface. Wild-type and engineered interface halves can be mixed to create two distinct Cre mutants, neither of which are functional in isolation, but which can form an active heterotetramer when combined. When these distinct mutants possess different DNA specificities, control over complex assembly directly discourages recombination at unwanted half-site combinations, enhancing the specificity of asymmetric site recombination. The engineered Cre mutants exhibit this assembly pattern in a variety of contexts, including mammalian cells. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  18. Specific Modulus and Density Profile as Characterization Criteria of Prefabricated Wood Composite Materials

    Directory of Open Access Journals (Sweden)

    Pavel Král

    2015-01-01

    Full Text Available Wood based product industry has developed and modified a wide range of products to cater changing demands of construction industry. Development of a product necessitates characterization to ensure compliance to established standards. Traditionally a product was characterized by properties like bending properties, density and swelling factor etc. Whereas, advances in technology has introduced more sophisticated parameters which represent a combination of various classical factors and provide more practical and detailed information. In this study, we procured four different types of commercial products, viz. Gypsum board, cement board, oriented strand board and gypsum fiber board and tried to characterized them using density profile ratio and stiffness ratio. We observed some interesting empirical relations between various parameters as represented in various plots.

  19. Hollow density profile on electron cyclotron resonance heating JFT-2M plasma

    International Nuclear Information System (INIS)

    Yamauchi, Toshihiko; Hoshino, Katsumichi; Kawashima, Hisato; Ogawa, Toshihide; Kawakami, Tomohide; Shiina, Tomio; Ishige, Youichi

    1998-01-01

    The first hollow electron density profile in the central region on the JAERI Fusion Torus-2M (JFT-2M) is measured during electron cyclotron resonance heating (ECRH) with a TV Thomson scattering system (TVTS). The peripheral region is not hollow but is accumulated due to pump-out from the central region. The hollowness increases with time but is saturated at ∼40 ms and maintains a constant hollow ratio. The hollowness is strongly related to the steep temperature gradient of the heated zone. (author)

  20. Copolymerization parameters of N-Methacryloyloxy tetrabromophthalimide with different vinyl monomers

    International Nuclear Information System (INIS)

    Mahmoud, A.A.

    2005-01-01

    N-Methacryloyloxytetrabromophthalimide (NMTP) was synthesized by the reaction of N-hydroxytetrabromophthalimide with either methacryloyl chloride or methacrylic acid in the presence of triethylamine or N, Ndicyclohexylcarbodiimide respectively. Binary copolymerization reactions of the prepared monomer with ethyl acrylate (EA), n-butyl methacrylate (n.BMA), tertiary butylacrylate (t.BA) and vinyl acetate (VA) were performed in methylene chloride at 65 degree C using 1 mol % azobisisobutylronitrile (AIBN) as initiator. The structure of the prepared monomer was investigated by IR and 1H NMR spectroscopy. The copolymer compositions were determined from bromine analysis. Copolymerization parameters for each system were calculated by the Fineman-Ross and Kelen-Tudos methods. The monomer reactivity ratios for the systems NMTP-EA, NMTP-n.BMA, NMTP-t.BA and NMTP-VA were found to be r1 0.180, r2 = 0.893, r1 = 0.025, r2 = 0.680, r1 0.014, r2 0.956 and r1 1.002, r2 1.004 respectively

  1. Improved i-motif thermal stability by insertion of anthraquinone monomers

    DEFF Research Database (Denmark)

    Gouda, Alaa S; Amine, Mahasen S.; Pedersen, Erik Bjerregaard

    2017-01-01

    In order to gain insight into how to improve thermal stability of i-motifs when used in the context of biomedical and nanotechnological applications, novel anthraquinone-modified i-motifs were synthesized by insertion of 1,8-, 1,4-, 1,5- and 2,6-disubstituted anthraquinone monomers into the TAA...... loops of a 22mer cytosine-rich human telomeric DNA sequence. The influence of the four anthraquinone linkers on the i-motif thermal stability was investigated at 295 nm and pH 5.5. Anthraquinone monomers modulate the i-motif stability in a position-depending manner and the modulation also depends...... unlocked nucleic acid monomers or twisted intercalating nucleic acid. The 2,6-disubstituted anthraquinone linker replacing T10 enabled a significant increase of i-motif thermal melting by 8.2 °C. A substantial increase of 5.0 °C in i-motif thermal melting was recorded when both A6 and T16 were modified...

  2. Relativistic self-focusing of ultra-high intensity X-ray laser beams in warm quantum plasma with upward density profile

    International Nuclear Information System (INIS)

    Habibi, M.; Ghamari, F.

    2014-01-01

    The results of a numerical study of high-intensity X-ray laser beam interaction with warm quantum plasma (WQP) are presented. By means of an upward ramp density profile combined with quantum factors specially the Fermi velocity, we have demonstrated significant relativistic self-focusing (RSF) of a Gaussian electromagnetic beam in the WQP where the Fermi temperature term in the dielectric function is important. For this purpose, we have considered the quantum hydrodynamics model that modifies refractive index of inhomogeneous WQPs with the inclusion of quantum correction through the quantum statistical and diffraction effects in the relativistic regime. Also, to better illustration of the physical difference between warm and cold quantum plasmas and their effect on the RSF, we have derived the envelope equation governing the spot size of X-ray laser beam in Q-plasmas. In addition to the upward ramp density profile, we have found that the quantum effects would be caused much higher oscillation and better focusing of X-ray laser beam in the WQP compared to that of cold quantum case. Our computational results reveal the importance of the use of electrons density profile and Fermi speed in enhancing self-focusing of laser beam

  3. Guidelines To Select the N-Heterocyclic Carbene for the Organopolymerization of Monomers with a Polar Group

    KAUST Repository

    Falivene, Laura; Cavallo, Luigi

    2017-01-01

    be tuned by the hindrance of the NHC and the nature of the monomer. In addition to rationalize existing systems, the 45 NHC/monomer combinations we examined can be used as a guideline to predict the behavior of a new NHC/monomer combination.

  4. Ortho-substituted triptycene-based diamines, monomers, and polymers, methods of making and uses thereof

    KAUST Repository

    Ghanem, Bader Saleh

    2017-04-13

    Described herein are ortho-dimethyl-substituted and tetramethyi-substituted triptycene-containing diamine monomers and microporous triptycene-based poiyimides and poiyamides, and methods of making the monomers and polymers.

  5. Ortho-substituted triptycene-based diamines, monomers, and polymers, methods of making and uses thereof

    KAUST Repository

    Ghanem, Bader Saleh; Pinnau, Ingo

    2017-01-01

    Described herein are ortho-dimethyl-substituted and tetramethyi-substituted triptycene-containing diamine monomers and microporous triptycene-based poiyimides and poiyamides, and methods of making the monomers and polymers.

  6. Constraining Saturn's interior density profile from precision gravity field measurement obtained during Grand Finale

    Science.gov (United States)

    Movshovitz, N.; Fortney, J. J.; Helled, R.; Hubbard, W. B.; Mankovich, C.; Thorngren, D.; Wahl, S. M.; Militzer, B.; Durante, D.

    2017-12-01

    The external gravity field of a planetary body is determined by the distribution of mass in its interior. Therefore, a measurement of the external field, properlyinterpreted, tells us about the interior density profile, ρ(r), which in turn can be used to constrain the composition in the interior and thereby learn about theformation mechanism of the planet. Recently, very high precision measurements of the gravity coefficients for Saturn have been made by the radio science instrument on the Cassini spacecraft during its Grand Finale orbits. The resulting coefficients come with an associated uncertainty. The task of matching a given density profile to a given set of gravity coefficients is relatively straightforward, but the question of how to best account for the uncertainty is not. In essentially all prior work on matching models to gravity field data inferences about planetary structure have rested on assumptions regarding the imperfectly known H/He equation of state and the assumption of an adiabatic interior. Here we wish to vastly expand the phase space of such calculations. We present a framework for describing all the possible interior density structures of a Jovian planet constrained by a given set of gravity coefficients and their associated uncertainties. Our approach is statistical. We produce a random sample of ρ(a) curves drawn from the underlying (and unknown) probability distribution of all curves, where ρ is the density on an interior level surface with equatorial radius a. Since the resulting set of density curves is a random sample, that is, curves appear with frequency proportional to the likelihood of their being consistent with the measured gravity, we can compute probability distributions for any quantity that is a function of ρ, such as central pressure, oblateness, core mass and radius, etc. Our approach is also Bayesian, in that it can utilize any prior assumptions about the planet's interior, as necessary, without being overly

  7. Structure of human insulin monomer in water/acetonitrile solution

    Energy Technology Data Exchange (ETDEWEB)

    Bocian, Wojciech; Sitkowski, Jerzy; Bednarek, Elzbieta [National Medicines Institute (Poland); Tarnowska, Anna; Kawecki, Robert [Institute of Organic Chemistry Polish Academy of Sciences (Poland); Kozerski, Lech [National Medicines Institute (Poland)], E-mail: lkoz@icho.edu.pl

    2008-01-15

    Here we present evidence that in water/acetonitrile solvent detailed structural and dynamic information can be obtained for important proteins that are naturally present as oligomers under native conditions. An NMR-derived human insulin monomer structure in H{sub 2}O/CD{sub 3}CN, 65/35 vol%, pH 3.6 is presented and compared with the available X-ray structure of a monomer that forms part of a hexamer (Acta Crystallogr. 2003 Sec. D59, 474) and with NMR structures in water and organic cosolvent. Detailed analysis using PFGSE NMR, temperature-dependent NMR, dilution experiments and CSI proves that the structure is monomeric in the concentration and temperature ranges 0.1-3 mM and 10-30 deg. C, respectively. The presence of long-range interstrand NOEs, as found in the crystal structure of the monomer, provides the evidence for conservation of the tertiary structure. Starting from structures calculated by the program CYANA, two different molecular dynamics simulated annealing refinement protocols were applied, either using the program AMBER in vacuum (AMBER{sub V}C), or including a generalized Born solvent model (AMBER{sub G}B)

  8. Determination of unreacted monomers in restorative dental resins based on dimethacrylate by NMR hydrogen

    International Nuclear Information System (INIS)

    Correa, Ivo Carlos; Miranda Junior, Walter G.; Tavares, Maria Ines B.

    2001-01-01

    The presence of unreacted monomers after photo-activation of dental composites causes mechanical and biological properties to decrease and could be detected by NMR analysis. The aim of this study was to evaluate the percentage of leachable monomers of light-cured composites under the effect of variations of exposure time of photo activation by nuclear magnetic resonance of hydrogen in solution (NMR 1 H). The composite resins tested Z250 and Fill Magic obtained similar values of unreacted monomers (%) at photo curing time suggested by the manufacturer and values were also lower than Durafill and A110 concentrations. From the NMR results, one day extractable time was efficient to quantify the amount of residual monomers in the dental composites tested, unless for Durafill composite. (author)

  9. Photopolymerizable phosphate acrylates as comonomers in dental adhesives with or without triclosan monomer units

    International Nuclear Information System (INIS)

    Melinte, Violeta; Buruiana, Tinca; Aldea, Horia; Matiut, Simona; Silion, Mihaela; Buruiana, Emil C.

    2014-01-01

    Phosphate diacrylates (CO-DAP, TMP-DAP) based on castor oil or trimethylolpropane were synthesized and evaluated in dental adhesive formulations in comparison with 3-acryloyloxy-2-hydroxypropyl methacrylate phosphate (AMP-P). In an attempt to promote antibacterial activity, another photopolymerizable monomer (TCS-UMA) containing 5-chloro-2-(2,4-dichlorophenoxy)phenol moiety (triclosan) was prepared and incorporated in adhesive resins. Each of these monomers had a molecular structure confirmed by spectral methods. The photopolymerization rates for monomers (0.063–0.088 s −1 ) were lower than those determined in the monomer combinations (0.116–0.158 s −1 ) incorporating phosphate diacrylate (11 wt.%), BisGMA (33 wt.%), TEGDMA (10 wt.%), UDMA (10 wt.%) and HEMA (15 wt.%), the degree of conversion varying between 63.4 and 74.5%. The formed copolymers showed high values for water sorption (18.65–57.02 μg/mm 3 ) and water solubility (3.51–13.38 μg/mm 3 ), and the contact angle was dependent on the presence of CO-DAP (θ F1 : 66.67°), TMP-DAP (θ F2 : 55.05°) or AMP-P (θ F3 : 52.90°) in the photocrosslinked specimens compared to the sample without phosphate monomer (θ F4 : 82.14°). The scanning electron microscopy image of the dentin–resin composite interface after applying our F1 formulation (pH: 4.1) and its light-curing for 20 s supports the evidence of the formation of the hybrid layer with the tooth structure created by self-etching approach, with no gaps or cracks in the adhesive. A comparative analysis of the adhesion achieved with commercial adhesive systems (Single Bond Universal, C-Bond) rather indicates similarities than differences between them. The addition of triclosan methacrylate (1 wt.%) into the formulation inhibited the bacterial growth of the Streptococcus mutans and Escherichia coli in the direct contact area due to the covalently linked antibacterial monomer. - Highlights: • Synthesis of photopolymerizable phosphate acrylate

  10. Oligodeoxynucleotides containing 2'-amino-LNA nucleotides as constrained morpholino phosphoramidate and phosphorodiamidate monomers

    DEFF Research Database (Denmark)

    Kristensen, Kim Vejlegaard; Paul, Sibasish; Kosbar, Tamer

    2017-01-01

    Incorporation in a 2'→5' direction of a phosphorodiamidite 2'-amino-LNA-T nucleotide as the morpholino phosphoramidate and N,N-dimethylamino phosphorodiamidate monomers into six oligonucleotides is reported. Thermal denaturation studies showed that the novel 2'-amino-LNA-based morpholino monomers...

  11. Monomer-Polymer Chemistry and the Impregnation Process

    Energy Technology Data Exchange (ETDEWEB)

    Stannett, V. [North Carolina State University, Raleigh, NC (United States)

    1968-10-15

    A brief outline of early polymerization techniques is followed by a description of polymerization process chemistry, impregnation and polymerization methods and criteria for the choice of monomer. General considerations, including the effects of polymerization inhibitors, swelling agents, radiation dose rate and sample thickness, are enumerated. (author)

  12. Effects of gel composition on the radiation induced density change in PAG polymer gel dosimeters: a model and experimental investigations

    International Nuclear Information System (INIS)

    Hilts, M; Jirasek, A; Duzenli, C

    2004-01-01

    Due to a density change that occurs in irradiated polyacrylamide gel (PAG), x-ray computed tomography (CT) has emerged as a feasible method of performing polymer gel dosimetry. However, applicability of the technique is currently limited by low sensitivity of the density change to dose. This work investigates the effect of PAG composition on the radiation induced density change and provides direction for future work in improving the sensitivity of CT polymer gel dosimetry. A model is developed that describes the PAG density change (Δρ gel ) as a function of both polymer yield (%P) and an intrinsic density change, per unit polymer yield, that occurs on conversion of monomer to polymer (Δρ polymer ). %P is a function of the fraction of monomer consumed and the weight fraction of monomer in the unirradiated gel (%T). Applying the model to experimental CT and Raman spectroscopic data, two important fundamental properties of the response of PAG density to dose (Δρ gel dose response) are discovered. The first property is that Δρ polymer depends on PAG %C (cross-linking fraction of total monomer) such that low and high %C PAGs exhibit a higher Δρ polymer than do more intermediate %C PAGs. This relationship is opposite to the relationship of polymer yield to %C and is explained by the effect of %C on the type of polymer formed. The second property is that the Δρ gel dose response is linearly dependent on %T. From the model, the inference is that, at least for %T≤12%, monomer consumption and Δρ polymer depend solely on %C. In terms of optimizing CT polymer gel dosimetry for high sensitivity, these results indicate that Δρ polymer can be expected to vary with each polymer gel system and thus should be considered when choosing a polymer gel for CT gel dosimetry. However, Δρ polymer and %P cannot be maximized simultaneously and maximizing %P, by choosing gels with intermediate %C and high %T, is found to have the greatest impact on increasing the

  13. Dynamic mechanical properties of photopolymerizable poly(vinyl alcohol)-acrylate monomer blends

    International Nuclear Information System (INIS)

    Koshiba, M.; Yamaoka, T.; Tsunoda, T.

    1983-01-01

    Dynamic mechanical properties of photopolymerizable poly(vinyl alcohol) (PVA)-monoacrylate blends were investigated by measuring dynamic shear modulus G' and loss tangent, tan delta. The dynamic mechanical properties of the blends before being exposed to UV irradiation were governed by the weight percent of the monomers which act as plasticizers. On the other hand, the UV-irradiated blends seemed to be typical two-phase materials since they revealed two tan delta maxima whose positions were independent of the monomer content. Those two maxima were assigned to PVA and photopolymerized acrylates with reference to the dynamic mechanical data of PVA and a PVA-polyacrylamide polyblend. Those dynamic mechanical data suggested that insolubilization of the blend type photopolymers should be caused by a decrease in solubility due to graft polymerization of acrylate monomers onto PVA. 9 figures, 3 tables

  14. Macroradical initiated polymerisation of acrylic and methacrylic monomers.

    Science.gov (United States)

    Mijangos, Irene; Guerreiro, António; Piletska, Elena; Whitcombe, Michael J; Karim, Kal; Chianella, Iva; Piletsky, Sergey

    2009-10-01

    An approach has been developed for the grafting of monomers onto poly(trimethylolpropane trimethacrylate) (polyTRIM) particles using 2,2-diethyl dithiocarbamic acid benzyl ester (DDCABE) as an initiator. A set of polymers was prepared with this technique over different lengths of time and the kinetics of the reaction studied experimentally. It was found that the grafting of initiator to the polymeric support followed a second order reaction, while the subsequent addition of monomers from solution into the polyTRIM macroradicals followed a first order reaction. The living nature of the iniferter modified macroradicals permits easy consecutive grafting of multiple polymeric layers, allowing straightforward functionalisation of particles. However, the effectiveness of the grafted initiator decreased with each cycle of polymerisation. This technique can be used for a wide range of applications in analytical and biochemistry.

  15. Residual monomer content determination in some acrylic denture base materials and possibilities of its reduction

    Directory of Open Access Journals (Sweden)

    Kostić Milena

    2009-01-01

    Full Text Available Background/Aim. Polymethyl methacrylate is used for producing a denture basis. It is a material made by the polymerization process of methyl methacrylate. Despite of the polymerization type, there is a certain amount of free methyl methacrylate (residual monomer incorporated in the denture, which can cause irritation of the oral mucosa. The aim of this study was to determine the amount of residual monomer in four different denture base acrylic resins by liquid chromatography and the possibility of its reduction. Methods. After the polymerization, a postpolymerization treatment was performed in three different ways: in boiling water for thirty minutes, with 500 W microwaves for three minutes and in steam bath at 22º C for one to thirty days. Results. The obtained results showed that the amount of residual monomer is significantly higher in cold polymerizing acrylates (9.1-11%. The amount of residual monomer after hot polymerization was in the tolerance range (0.59- 0.86%. Conclusion. The obtained results denote a low content of residual monomer in the samples which have undergone postpolymerization treatment. A lower percent of residual monomer is established in samples undergone a hot polymerization.

  16. Guidelines To Select the N-Heterocyclic Carbene for the Organopolymerization of Monomers with a Polar Group

    KAUST Repository

    Falivene, Laura

    2017-02-13

    We report on the DFT stability of zwitterion and spirocycle adducts of five polar monomers with nine N-heterocyclic carbenes (NHC), covering the most typical classes of monomers and NHCs used in organopolymerization. Results indicate that the relative stability of the two adducts is dominated by the singlet-triplet energy gap of the free NHC, with low energy gaps favoring the spirocycle adduct, while high energy gaps favor the zwitterionic adduct. This basic structure/property relationship can be tuned by the hindrance of the NHC and the nature of the monomer. In addition to rationalize existing systems, the 45 NHC/monomer combinations we examined can be used as a guideline to predict the behavior of a new NHC/monomer combination.

  17. Quantum Hall states of atomic Bose gases: Density profiles in single-layer and multilayer geometries

    International Nuclear Information System (INIS)

    Cooper, N. R.; Lankvelt, F. J. M. van; Reijnders, J. W.; Schoutens, K.

    2005-01-01

    We describe the density profiles of confined atomic Bose gases in the high-rotation limit, in single-layer and multilayer geometries. We show that, in a local-density approximation, the density in a single layer shows a landscape of quantized steps due to the formation of incompressible liquids, which are analogous to fractional quantum Hall liquids for a two-dimensional electron gas in a strong magnetic field. In a multilayered setup we find different phases, depending on the strength of the interlayer tunneling t. We discuss the situation where a vortex lattice in the three-dimensional condensate (at large tunneling) undergoes quantum melting at a critical tunneling t c 1 . For tunneling well below t c 1 one expects weakly coupled or isolated layers, each exhibiting a landscape of quantum Hall liquids. After expansion, this gives a radial density distribution with characteristic features (cusps) that provide experimental signatures of the quantum Hall liquids

  18. Radiation cured and monomer modified silicon elastomers

    International Nuclear Information System (INIS)

    Eldred, R.J.

    1979-01-01

    A method is described for the production of a tear resistant silicone elastomer, which has improved elongation properties. This elastomer is the radiation induced reaction product of a noncured methyl vinyl silicone resin (VMQ) and uniformly dispersed therein a blend of a polyfunctional acrylic crosslinking monomer and a filler

  19. Softening and elution of monomers in ethanol

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Asmussen, Erik; Munksgaard, E Christian

    2009-01-01

    The purpose of this study was to investigate the effect of light-curing protocol on softening and elution of monomers in ethanol as measured on a model polymer. It was a further aim to correlate the measured values with previously reported data on degree of conversion and glass transition...

  20. Dislocation density and Burgers vector population in fiber-textured Ni thin films determined by high-resolution X-ray line profile analysis

    DEFF Research Database (Denmark)

    Csiszár, Gábor; Pantleon, Karen; Alimadadi, Hossein

    2012-01-01

    distribution are determined by high-resolution X-ray diffraction line profile analysis. The substructure parameters are correlated with the strength of the films by using the combined Taylor and Hall-Petch relations. The convolutional multiple whole profile method is used to obtain the substructure parameters......Nanocrystalline Ni thin films have been produced by direct current electrodeposition with different additives and current density in order to obtain 〈100〉, 〈111〉 and 〈211〉 major fiber textures. The dislocation density, the Burgers vector population and the coherently scattering domain size...

  1. Density and temperature profile modifications with electron cyclotron power injection in quiescent double barrier discharges on DIII-D

    International Nuclear Information System (INIS)

    Casper, T A; Burrell, K H; Doyle, E J; Gohil, P; Lasnier, C J; Leonard, A W; Moller, J M; Osborne, T H; Snyder, P B; Thomas, D M; Weiland, J; West, W P

    2006-01-01

    Quiescent double barrier (QDB) conditions often form when an internal transport barrier is created with high-power neutral-beam injection into a quiescent H-mode (QH) plasma. These QH-modes offer an attractive, high-performance operating scenario for burning plasma experiments due to their quasi-stationarity and lack of edge localized modes. Our initial experiments and modelling using ECH/ECCD in QDB shots were designed to control the current profile and, indeed, we have observed a strong dependence on the q-profile when EC-power is used inside the core transport barrier region. While strong electron heating is observed with EC power injection, we also observe a drop in the other core parameters, namely ion temperature and rotation, electron density and impurity concentration. At onset and termination of the EC pulse, dynamically changing conditions are induced that provide a rapid evolution of T e /T i profiles accessible with 0.3 e /T i ) axis e /T i ratio as the ion temperature and density profiles flatten with this change in transport. The change in transport is consistent with a destabilization of ITG turbulence as inferred from the reduction of the stability threshold due to the change in T e /T i

  2. Polyfunctional monomers as additives for enhancing the radiation copolymerization of styrene with polyethylene, polypropylene, and PVC

    International Nuclear Information System (INIS)

    Ang, C.H.; Garnett, J.L.; Levot, R.; Long, M.A.

    1982-01-01

    Additives which can increase the yield in the radiation grafting of monomers to polymers are useful. The use of polyfunctional monomers as additives (approx. = 1% v/v) are shown to enhance significantly the copolymerization yields of styrene in methanol to films of polyethylene and polypropylene under certain radiation conditions. The results obtained when the polyolefins are replaced by PVC as backbone polymer in these accelerated grafting reactions are reported. Divinylbenzene (DVB) and trimethylolpropane triacrylate (TMPTA) were used as representative polyfunctional monomers for the enhancement effect. When polypropylene was used as backbone polymer, the inclusion of DVB significantly enhanced the radiation grafting of styrene in methanol at all monomer concentrations studied above 35%. At certain monomer concentrations (50% , 60%), the yield of graft copolymer was almost doubled by the addition of DVB. 3 tables. (DP)

  3. Sustainable Poly(Ionic Liquids) for CO2 Capture Based on Deep Eutectic Monomers

    KAUST Repository

    Isik, Mehmet; Zulfiqar, Sonia; Edhaim, Fatimah; Ruiperez, Fernando; Rothenberger, Alexander; Mecerreyes, David

    2016-01-01

    The design of high performance solid sorbent materials for CO2 capture is a technology which has been employed to mitigate global warming. However, the covalent incorporation of functionalities into polymeric supports usually involves multistep energy-intensive chemical processes. This fact makes the net CO2 balance of the materials negative even though they possess good properties as CO2 sorbents. Here we show a new family of polymers which are based on amines, amidoximes, and natural carboxylic acids and can be obtained using sustainable low energy processes. Thus, deep eutectic monomers based on natural carboxylic acids, amidoximes, and amines have been prepared by just mixing with cholinium type methacrylic ammonium monomer. The formation of deep eutectic monomers was confirmed by differential scanning calorimetry measurements. In all cases, the monomers displayed glass transition temperatures well below room temperature. Computational studies revealed that the formation of eutectic complexes lengthens the distance between the cation and the anion causing charge delocalization. The liquid nature of the resulting deep eutectic monomers (DEMs) made it possible to conduct a fast photopolymerization process to obtain the corresponding poly(ionic liquids). Materials were characterized by means of nuclear magnetic resonance, differential scanning calorimetry, thermogravimetric analysis, and X-ray diffraction to evaluate the properties of the polymers. The polymers were then used as solid sorbents for CO2 capture. It has been shown that the polymers prepared with citric acid displayed better performance both experimentally and computationally. The current endeavor showed that sustainable poly(ionic liquids) based on deep eutectic monomers can be easily prepared to produce low-energy-cost alternatives to the materials currently being researched for CO2 capture. © 2016 American Chemical Society.

  4. Sustainable Poly(Ionic Liquids) for CO2 Capture Based on Deep Eutectic Monomers

    KAUST Repository

    Isik, Mehmet

    2016-10-05

    The design of high performance solid sorbent materials for CO2 capture is a technology which has been employed to mitigate global warming. However, the covalent incorporation of functionalities into polymeric supports usually involves multistep energy-intensive chemical processes. This fact makes the net CO2 balance of the materials negative even though they possess good properties as CO2 sorbents. Here we show a new family of polymers which are based on amines, amidoximes, and natural carboxylic acids and can be obtained using sustainable low energy processes. Thus, deep eutectic monomers based on natural carboxylic acids, amidoximes, and amines have been prepared by just mixing with cholinium type methacrylic ammonium monomer. The formation of deep eutectic monomers was confirmed by differential scanning calorimetry measurements. In all cases, the monomers displayed glass transition temperatures well below room temperature. Computational studies revealed that the formation of eutectic complexes lengthens the distance between the cation and the anion causing charge delocalization. The liquid nature of the resulting deep eutectic monomers (DEMs) made it possible to conduct a fast photopolymerization process to obtain the corresponding poly(ionic liquids). Materials were characterized by means of nuclear magnetic resonance, differential scanning calorimetry, thermogravimetric analysis, and X-ray diffraction to evaluate the properties of the polymers. The polymers were then used as solid sorbents for CO2 capture. It has been shown that the polymers prepared with citric acid displayed better performance both experimentally and computationally. The current endeavor showed that sustainable poly(ionic liquids) based on deep eutectic monomers can be easily prepared to produce low-energy-cost alternatives to the materials currently being researched for CO2 capture. © 2016 American Chemical Society.

  5. Profiles of plasma parameters and density of negative hydrogen ions by laser detachment measurements in RF-driven ion sources

    International Nuclear Information System (INIS)

    Christ-Koch, Sina

    2007-01-01

    This work shows the application of the Laserdetachment method for spatially resolved measurements of negative Hydrogen/Deuterium ion density. It was applied on a high power low pressure RF-driven ion source. The Laser detachment method is based on the measurement of electron currents on a positively biased Langmuir probe before and during/after a laser pulse. The density ratio of negative ions to electrons can be derived from the ratio of currents to the probe. The absolute density of negative ions can be obtained when the electron density is measured with the standard Langmuir probe setup. Measurements with the Langmuir probe additionally yield information about the floating and plasma potential, the electron temperature and the density of positive ions. The Laser detachment setup had to be adapted to the special conditions of the RF-driven source. In particular the existence of RF fields (1 MHz), high source potential (-20 kV), magnetic fields (∝ 7 mT) and caesium inside the source had to be considered. The density of negative ions could be identified in the range of n(H - )=1.10 17 1/m 3 , which is in the same order of magnitude as the electron density. Only the application of the Laser detachment method with the Langmuir probe measurements will yield spatially resolved plasma parameters and H- density profiles. The influence of diverse external parameters, such as pressure, RF-power, magnetic fields on the plasma parameters and their profiles were studied and explained. Hence, the measurements lead to a detailed understanding of the processes inside the source. (orig.)

  6. Functionalized Nanoporous Polymer Membranes with Well-Defined Pore Architectures via Lyotropic Liquid-Crystalline Monomers

    National Research Council Canada - National Science Library

    Gin, Douglas

    1997-01-01

    .... Two lyotropic liquid-crystalline monomer platforms have been synthesized. The interchannel separations in the polymerizable materials can be varied in the 30-40 A range by the choice of counterion on the ionic headgroup of the monomers...

  7. Photopolymerizable phosphate acrylates as comonomers in dental adhesives with or without triclosan monomer units

    Energy Technology Data Exchange (ETDEWEB)

    Melinte, Violeta [Petru Poni Institute of Macromolecular Chemistry, 41 A Gr. Ghica Voda Alley, 700487 Iasi (Romania); Buruiana, Tinca, E-mail: tbur@icmpp.ro [Petru Poni Institute of Macromolecular Chemistry, 41 A Gr. Ghica Voda Alley, 700487 Iasi (Romania); Aldea, Horia [Gr. T. Popa University of Medicine and Pharmacy, Faculty of Dentistry, Iasi (Romania); Matiut, Simona [Praxis Medical Investigations, 33 Independence, 700102 Iasi (Romania); Silion, Mihaela; Buruiana, Emil C. [Petru Poni Institute of Macromolecular Chemistry, 41 A Gr. Ghica Voda Alley, 700487 Iasi (Romania)

    2014-01-01

    Phosphate diacrylates (CO-DAP, TMP-DAP) based on castor oil or trimethylolpropane were synthesized and evaluated in dental adhesive formulations in comparison with 3-acryloyloxy-2-hydroxypropyl methacrylate phosphate (AMP-P). In an attempt to promote antibacterial activity, another photopolymerizable monomer (TCS-UMA) containing 5-chloro-2-(2,4-dichlorophenoxy)phenol moiety (triclosan) was prepared and incorporated in adhesive resins. Each of these monomers had a molecular structure confirmed by spectral methods. The photopolymerization rates for monomers (0.063–0.088 s{sup −1}) were lower than those determined in the monomer combinations (0.116–0.158 s{sup −1}) incorporating phosphate diacrylate (11 wt.%), BisGMA (33 wt.%), TEGDMA (10 wt.%), UDMA (10 wt.%) and HEMA (15 wt.%), the degree of conversion varying between 63.4 and 74.5%. The formed copolymers showed high values for water sorption (18.65–57.02 μg/mm{sup 3}) and water solubility (3.51–13.38 μg/mm{sup 3}), and the contact angle was dependent on the presence of CO-DAP (θ{sub F1}: 66.67°), TMP-DAP (θ{sub F2}: 55.05°) or AMP-P (θ{sub F3}: 52.90°) in the photocrosslinked specimens compared to the sample without phosphate monomer (θ{sub F4}: 82.14°). The scanning electron microscopy image of the dentin–resin composite interface after applying our F1 formulation (pH: 4.1) and its light-curing for 20 s supports the evidence of the formation of the hybrid layer with the tooth structure created by self-etching approach, with no gaps or cracks in the adhesive. A comparative analysis of the adhesion achieved with commercial adhesive systems (Single Bond Universal, C-Bond) rather indicates similarities than differences between them. The addition of triclosan methacrylate (1 wt.%) into the formulation inhibited the bacterial growth of the Streptococcus mutans and Escherichia coli in the direct contact area due to the covalently linked antibacterial monomer. - Highlights: • Synthesis of

  8. Thermodynamically stable amyloid-β monomers have much lower membrane affinity than the small oligomers

    Directory of Open Access Journals (Sweden)

    Bidyut eSarkar

    2013-04-01

    Full Text Available Amyloid beta (Aβ is an extracellular 39-43 residue long peptide present in the mammalian cerebrospinal fluid, whose aggregation is associated with Alzheimer’s disease. Small oligomers of Aβ are currently thought to be the key to toxicity. However, it is not clear why the monomers of Aβ are non-toxic, and at what stage of aggregation toxicity emerges. Interactions of Aβ with cell membranes is thought to be the initiator of toxicity, but membrane-binding studies with different preparations of monomers and oligomers have not settled this issue. We have earlier found that thermodynamically stable Aβ monomers emerge spontaneously from oligomeric mixtures upon long term incubation in physiological solutions (Nag et al, JBC, 2011. Here we show that the membrane-affinity of these stable Aβ monomers is much lower than that of a mixture of small oligomers (containing dimers to decamers, providing a clue to the emergence of toxicity. Fluorescently labeled Aβ40 monomers show negligible binding to cell membranes of a neuronal cell line (RN46A at physiological concentrations (250 nM, while oligomers at the same concentrations show strong binding within 30 minutes of incubation. The increased affinity most likely does not require any specific neuronal receptor, since this difference in membrane-affinity was also observed in a somatic cell-line (HEK 293T. Similar results are also obtained for Aβ42 monomers and oligomers. Minimal amount of cell death is observed at these concentrations even after 36 hours of incubation. It is likely that membrane binding precedes subsequent slower toxic events induced by Aβ. Our results a provide an explanation for the non-toxic nature of Aβ monomers, b suggest that Aβ toxicity emerges at the initial oligomeric phase, and c provide a quick assay for monitoring the benign-to-toxic transformation of Aβ.

  9. Do the monomers release from the composite resins after artificial aging?

    Science.gov (United States)

    Tokay, Ugur; Koyuturk, Alp Erdin; Aksoy, Abdurrahman; Ozmen, Bilal

    2015-04-01

    The aim of this study is to measure the effect of thermal cycling on the amount of monomer released from three different composite materials by HPLC analysis method. Three different composite materials, inlay composite, posterior composite and micro-hybrid composite were used. Sixty cylinder specimens each with a dimension of approximately 1 cm width and 3 mm depth, were prepared before experiments were carried out. Inlay composite material was polymerized according to manufacturers' instructions. Thermal cycling device was used to simulate thermal differences which occur in the mouth media. Monomers were analyzed using HPLC technic after thermal cycling process. The amount of ethoxylated Bis-GMA and urethane dimethacrylate (UDMA) in inlay composite material, the amount of ethoxylated Bis-GMA in posterior composite material, the amount of ethoxylated Bis-GMA and triethyleneglycol dimethacrylate (TEGDMA) in micro-hybrid composite material were investigated. Monomer release of thermal cycles levels showed a linear increase in UDMA and TEGDMA (P < 0.05). In terms of thermal cycles levels, Bis-EMA released from posterior composite showed a cubic change (P < 0.001). It was observed that use of additional polymerization processes might have positive effect on the decrease of residual monomer. In the light of the results, we suggest that indirect composite resins have more outstanding features than direct composite resins in terms of biocompatibility. © 2015 Wiley Periodicals, Inc.

  10. Inter-ELM evolution of the edge current density profile on the ASDEX Upgrade tokamak

    International Nuclear Information System (INIS)

    Dunne, Michael G.

    2014-01-01

    The sudden decrease of plasma stored energy and subsequent power deposition on the first wall of a tokamak device due to edge localised modes (ELMs) is potentially detrimental to the success of a future fusion reactor. Understanding and control of ELMs is critical for the longevity of these devices and also to maximise their performance. The commonly accepted picture of ELMs posits a critical pressure gradient and current density in the plasma edge, above which coupled magnetohydrodynamic (MHD) peeling-ballooning modes are driven unstable. Much analysis has been presented in recent years on the spatial and temporal evolution of the edge pressure gradient. However, the edge current density has typically been overlooked due to the difficulties in measuring this quantity. In this thesis, a novel method of current density recovery is presented, using the equilibrium solver CLISTE to reconstruct a high resolution equilibrium utilising both external magnetic and internal edge kinetic data measured on the ASDEX Upgrade (AUG) tokamak. The evolution of the edge current density relative to an ELM crash is presented, showing that a resistive delay in the buildup of the current density is unlikely. An uncertainty analysis shows that the edge current density can be determined with an accuracy consistent with that of the kinetic data used. A comparison with neoclassical theory demonstrates excellent agreement between the current density determined by CLISTE and the calculated profiles. Three ELM mitigation regimes are investigated: Type-II ELMs, ELMs suppressed by external magnetic perturbations (MPs), and Nitrogen seeded ELMs. In the first two cases, the current density is found to decrease as mitigation onsets, indicating a more ballooning-like plasma behaviour. In the latter case, the flux surface averaged current density can decrease while the local current density increases, thus providing a mechanism to suppress both the peeling and ballooning modes.

  11. Inter-ELM evolution of the edge current density profile on the ASDEX Upgrade tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Dunne, Michael G.

    2014-02-15

    The sudden decrease of plasma stored energy and subsequent power deposition on the first wall of a tokamak device due to edge localised modes (ELMs) is potentially detrimental to the success of a future fusion reactor. Understanding and control of ELMs is critical for the longevity of these devices and also to maximise their performance. The commonly accepted picture of ELMs posits a critical pressure gradient and current density in the plasma edge, above which coupled magnetohydrodynamic (MHD) peeling-ballooning modes are driven unstable. Much analysis has been presented in recent years on the spatial and temporal evolution of the edge pressure gradient. However, the edge current density has typically been overlooked due to the difficulties in measuring this quantity. In this thesis, a novel method of current density recovery is presented, using the equilibrium solver CLISTE to reconstruct a high resolution equilibrium utilising both external magnetic and internal edge kinetic data measured on the ASDEX Upgrade (AUG) tokamak. The evolution of the edge current density relative to an ELM crash is presented, showing that a resistive delay in the buildup of the current density is unlikely. An uncertainty analysis shows that the edge current density can be determined with an accuracy consistent with that of the kinetic data used. A comparison with neoclassical theory demonstrates excellent agreement between the current density determined by CLISTE and the calculated profiles. Three ELM mitigation regimes are investigated: Type-II ELMs, ELMs suppressed by external magnetic perturbations (MPs), and Nitrogen seeded ELMs. In the first two cases, the current density is found to decrease as mitigation onsets, indicating a more ballooning-like plasma behaviour. In the latter case, the flux surface averaged current density can decrease while the local current density increases, thus providing a mechanism to suppress both the peeling and ballooning modes.

  12. Inhibition of odontogenic differentiation of human dental pulp cells by dental resin monomers.

    Science.gov (United States)

    Kwon, Ji Hyun; Park, Hee Chul; Zhu, Tingting; Yang, Hyeong-Cheol

    2015-01-01

    Dental resin monomers that are leached from the resin matrix due to incomplete polymerization can affect the viability and various functions of oral tissues and cells. In this study, the effects of triethylene glycol dimethacrylate (TEGDMA) and 2-hydroxyethyl methacrylate (HEMA) on odontogenic differentiation of human dental pulp cells (HDPCs) were examined. To mimic clinical situations, dental pulp cells were treated with resin monomers for 24 h prior to the analysis of alkaline phosphatase (ALP) activity and mRNA expression of genes related to pulp cell differentiation. To elucidate the underlying signaling pathways, regulation of mitogen-activated protein (MAP) kinases by resin monomers was also investigated. The ALP activity of HDPCs was reduced by TEGDMA and HEMA at noncytotoxic concentrations. The mRNA expression of dentin sialophosphoprotein (DSPP), osteocalcin (OCN), and osteopontin (OPN) was also downregulated by resin monomers. However, DSPP expression was not affected by hydrogen peroxide (H2O2). Among the MAP kinases examined, ERK activation (ERK phosphorylation) was not affected by either resin monomers or H2O2, whereas JNK was phosphorylated by TEGDMA and HEMA. Phospho-p38 was upregulated by HEMA, while TEGDMA and H2O2 suppressed p38 phosphorylation. Exposure to TEGDMA and HEMA for a limited period suppresses differentiation of HDPCs via different signaling pathways.

  13. Net expansion of dried demineralized dentin matrix produced by monomer/alcohol saturation and solvent evaporation.

    Science.gov (United States)

    Agee, Kelli A; Becker, Thomas D; Joyce, Anthony P; Rueggeberg, Frederick A; Borke, James L; Waller, Jennifer L; Tay, Franklin R; Pashley, David H

    2006-11-01

    The purpose of this work was to determine if nonaqueous methacrylate monomer/alcohol mixtures could expand dried collapsed demineralized dentin matrix. Thin disks (ca. 200 microm) of human dentin were demineralized and placed in wells beneath contact probes of linear variable differential transformers. The probes were placed on water-saturated expanded matrices to record the shrinkage associated with drying. Monomer mixtures containing hydroxyethyl methacrylate, 2,2-bis[4-(2-hydroxy-3 methacryloyloxy)propoxyphenyl] propane, or triethyleneglycol dimethacrylate were mixed with methanol or ethanol at alcohol/monomer mass fraction % of 90/10, 70/30, 50/50, or 30/70. They were randomly applied to the dried matrices to determine the rate and magnitude of expansion; then shrinkage was recorded during evaporation of the alcohols. The results indicated that matrix expansion was positively correlated with the Hoy's solubility parameters for hydrogen bonding forces (delta(h)) of the monomer/solvent mixtures (p methanol-containing than with ethanol-containing monomer mixtures. For the test solutions, triethyleneglycol dimethacrylate-containing mixtures produced the slowest rate of matrix expansion and hydroxyethyl methacrylate-containing mixtures the most rapid expansion. When the solvents were evaporated, the matrix shrank in proportion to the solvent content and the delta(h) of the monomer-solvent mixtures. The results indicate that expansion of dried, collapsed dentin matrices requires that the delta(h) of the mixtures be larger than 17 (J/cm(3))(1/2). The greater the delta(h) of the monomer solutions, the greater the rate and extent of expansion.

  14. Synthesis of phosphate monomers and bonding to dentin: esterification methods and use of phosphorus pentoxide.

    Science.gov (United States)

    Ogliari, Fabrício Aulo; da Silva, Eduardo de Oliveira; Lima, Giana da Silveira; Madruga, Francine Cardozo; Henn, Sandrina; Bueno, Márcia; Ceschi, Marco Antônio; Petzhold, Cesar Liberato; Piva, Evandro

    2008-03-01

    The aim of this study was to synthesize an acidic monomer using an alternative synthetic pathway and to evaluate the influence of the acidic monomer concentration on the microtensile bond strength to dentin. The intermediary 5-hydroxypentyl methacrylate (HPMA) was synthesized through methacrylic acid esterification with 1,5-pentanediol, catalyzed by p-toluenesulfonic acid. To displace the reaction balance, the water generated by esterification was removed by three different methods: anhydrous sodium sulfate; molecular sieves or azeotropic distillation. In the next step, a phosphorus pentoxide (4.82 mmol) slurry was formed in cold acetone and 29 mmol of HPMA was slowly added by funnel addition. After the reaction ended, solvent was evaporated and the product was characterized by 1HNMR and FTIR. The phosphate monomer was introduced in a self-etch primer at concentrations of 0, 15, 30, 50, 70 and 100 wt%. Clearfil SE Bond was used as commercial reference. Microtensile bond strength to dentin was evaluated 24h after the bonding procedures, followed by fracture analysis (n=20). Data was submitted to ANOVA and Tukey's post hoc test. The highest yield was obtained (62%) when azeotropic distillation was used, while the reaction with molecular sieves was not feasible. The phosphoric moiety attachment to the monomer was successfully performed with a quantitative yield that reached around 100%. The acidic monomer concentration significantly affected the bond strength and the highest mean (55.1+/-12.8 MPa) was obtained when 50% of acidic monomer was used. The synthesis pathways described in the present study appear to be a viable alternative for developing phosphate monomers.

  15. Triptycene-based ladder monomers and polymers, methods of making each, and methods of use

    KAUST Repository

    Pinnau, Ingo; Ghanem, Bader; Swaidan, Raja

    2015-01-01

    Embodiments of the present disclosure provide for a triptycene-based A-B monomer, a method of making a triptycene-based A-B monomer, a triptycene-based ladder polymer, a method of making a triptycene-based ladder polymers, a method of using

  16. Density Profiles, Energy, and Oscillation Strength of a Quantum Dot in Two Dimensions with a Harmonic Oscillator External Potential using an Orbital-free Energy Functional Based on Thomas–Fermi Theory

    Directory of Open Access Journals (Sweden)

    Suhufa Alfarisa

    2016-03-01

    Full Text Available This research aims i to determine the density profile and calculate the ground state energy of a quantum dot in two dimensions (2D with a harmonic oscillator potential using orbital-free density functional theory, and ii to understand the effect of the harmonic oscillator potential strength on the electron density profiles in the quantum dot. This study determines the total energy functional of the quantum dot that is a functional of the density that depends only on spatial variables. The total energy functional consists of three terms. The first term is the kinetic energy functional, which is the Thomas–Fermi approximation in this case. The second term is the external potential. The harmonic oscillator potential is used in this study. The last term is the electron–electron interactions described by the Coulomb interaction. The functional is formally solved to obtain the electron density as a function of spatial variables. This equation cannot be solved analytically, and thus a numerical method is used to determine the profile of the electron density. Using the electron density profiles, the ground state energy of the quantum dot in 2D can be calculated. The ground state energies obtained are 2.464, 22.26, 90.1957, 252.437, and 496.658 au for 2, 6, 12, 20, and 56 electrons, respectively. The highest electron density is localized close to the middle of the quantum dot. The density profiles decrease with the increasing distance, and the lowest density is at the edge of the quantum dot. Generally, increasing the harmonic oscillator potential strength reduces the density profiles around the center of the quantum dot.

  17. Simulated X-ray galaxy clusters at the virial radius: Slopes of the gas density, temperature and surface brightness profiles

    Science.gov (United States)

    Roncarelli, M.; Ettori, S.; Dolag, K.; Moscardini, L.; Borgani, S.; Murante, G.

    2006-12-01

    Using a set of hydrodynamical simulations of nine galaxy clusters with masses in the range 1.5 × 1014 matter of tension between simulated and observed properties, and up to the virial radius and beyond, where present observations are unable to provide any constraints. We have modelled the radial profiles between 0.3R200 and 3R200 with power laws with one index, two indexes and a rolling index. The simulated temperature and [0.5-2] keV surface brightness profiles well reproduce the observed behaviours outside the core. The shape of all these profiles in the radial range considered depends mainly on the activity of the gravitational collapse, with no significant difference among models including extraphysics. The profiles steepen in the outskirts, with the slope of the power-law fit that changes from -2.5 to -3.4 in the gas density, from -0.5 to -1.8 in the gas temperature and from -3.5 to -5.0 in the X-ray soft surface brightness. We predict that the gas density, temperature and [0.5-2] keV surface brightness values at R200 are, on average, 0.05, 0.60, 0.008 times the measured values at 0.3R200. At 2R200, these values decrease by an order of magnitude in the gas density and surface brightness, by a factor of 2 in the temperature, putting stringent limits on the detectable properties of the intracluster-medium (ICM) in the virial regions.

  18. Constraining the interior density profile of a Jovian planet from precision gravity field data

    Science.gov (United States)

    Movshovitz, Naor; Fortney, Jonathan J.; Helled, Ravit; Hubbard, William B.; Thorngren, Daniel; Mankovich, Chris; Wahl, Sean; Militzer, Burkhard; Durante, Daniele

    2017-10-01

    The external gravity field of a planetary body is determined by the distribution of mass in its interior. Therefore, a measurement of the external field, properly interpreted, tells us about the interior density profile, ρ(r), which in turn can be used to constrain the composition in the interior and thereby learn about the formation mechanism of the planet. Planetary gravity fields are usually described by the coefficients in an expansion of the gravitational potential. Recently, high precision measurements of these coefficients for Jupiter and Saturn have been made by the radio science instruments on the Juno and Cassini spacecraft, respectively.The resulting coefficients come with an associated uncertainty. And while the task of matching a given density profile with a given set of gravity coefficients is relatively straightforward, the question of how best to account for the uncertainty is not. In essentially all prior work on matching models to gravity field data, inferences about planetary structure have rested on imperfect knowledge of the H/He equation of state and on the assumption of an adiabatic interior. Here we wish to vastly expand the phase space of such calculations. We present a framework for describing all the possible interior density structures of a Jovian planet, constrained only by a given set of gravity coefficients and their associated uncertainties. Our approach is statistical. We produce a random sample of ρ(a) curves drawn from the underlying (and unknown) probability distribution of all curves, where ρ is the density on an interior level surface with equatorial radius a. Since the resulting set of density curves is a random sample, that is, curves appear with frequency proportional to the likelihood of their being consistent with the measured gravity, we can compute probability distributions for any quantity that is a function of ρ, such as central pressure, oblateness, core mass and radius, etc. Our approach is also bayesian, in that

  19. Synthesis and characterization of copolymers from hindered amines and vinyl monomers

    Directory of Open Access Journals (Sweden)

    Marcelo Aparecido Chinelatto

    2014-01-01

    Full Text Available New copolymers from hindered amines and vinyl monomers were synthesized by radical chain polymerization. To obtain polymeric HALS, acrylamide-(1ATP and acrylate-(4ATP monomers, derivatives from 2,2,6,6-tetramethylpiperidine and 2,2,6,6-tetramethyl-4-piperidinol were synthesized. The radical chain polymerization of 1ATP with styrene (Sty using 1-butanethiol (BTN resulted in a copolymer with 95 units of Sty and 15 units of 1ATP. The radical chain polymerization of 1ATP and vinyl acetate (VAc has produced only 1ATP homopolymer. In the chain polymerization of 4ATP with Sty or VAc, the hydrogen atom bonded to the nitrogen of 4ATP is labile enough to originate another radical at this site. The steric hindrance imposed by methyl groups on this bonding site hampers its reaction with other propagating species and the formation of a copolymer or network structure will be dependent on the size of the pendent group in the vinyl monomer.

  20. Testing of residual monomer content reduction possibility on acrilic resins quality

    Directory of Open Access Journals (Sweden)

    Kostić Milena

    2011-01-01

    Full Text Available Poly (methyl methacrylate (PMMA is material widely used in dentistry. Despite the various methods used to initiate the polymerization of acrylic resins, the conversion of monomer to polymer is not complete thus leaving some unreacted methyl methacrylate (MMA, known as residual monomer (RM, in denture structure. RM in dental acrylic resins has deleterious effects on their mechanical properties and their biocompatibility. The objective of the work was to test the residual monomer reduction possibility by applying the appropriate postpolymerization treatment as well as to determine the effects of this reduction on pressure yields stress and surface structure characteristics of the acrylic resins. Postpolymerization treatments and water storage induced reduction of RM amount in cold-polymerized acrylic resins improved their mechanical properties and the homogenized surface structure. After the polymerization of heat-polymerized acrylic resins the post-polymerization treatments for improving the quality of this material type are not necessary.

  1. Chapter 7: High-Density H-Mode Operation in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Stober, Joerg Karl; Lang, Peter Thomas; Mertens, Vitus

    2003-01-01

    Recent results are reported on the maximum achievable H-mode density and the behavior of pedestal density and central density peaking as this limit is approached. The maximum achievable H-mode density roughly scales as the Greenwald density, though a dependence on B t is clearly observed. In contrast to the stiff temperature profiles, the density profiles seem to allow more shape variation and especially with high-field-side pellet-injection, strongly peaked profiles with good confinement have been achieved. Also, spontaneous density peaking at high densities is observed in ASDEX Upgrade, which is related to the generally observed large time constants for the density profile equilibration. The equilibrated density profile shapes depend strongly on the heat-flux profile in the sense that central heating leads to significantly flatter profiles

  2. Visualization of monomer and polymer inside porous stones by using X-ray tomography

    International Nuclear Information System (INIS)

    Brunetti, Antonio; Princi, Elisabetta; Vicini, Silvia; Pincin, Silvia; Bidali, Simone; Mariani, Alberto

    2004-01-01

    Estimate of sorption of liquid materials inside porous stones is an important parameter in industrial material testing and cultural heritage conservation. In the latter case, a suitable polymer can be used for both consolidation and conservation, it being applied either in the final form or as its parent monomer, which is subsequently allowed to polymerize in situ by the classical method or by frontal polymerization. However, the sorption of such materials through the stone is often difficult because of their viscosity and/or stone porosity. For this reason, the amount of monomer (or polymer) is a parameter of great interest in order to determine the extent of protection reachable by the treatment. In this paper a new methodology based on X-ray tomography is presented. The methodology makes use of a contrast agent added to the monomer that does not interact with its propagation inside the stone and allows to increase the absorption coefficient and so to observe the monomer inside the sample, which is finally frontally polymerized

  3. The influence of monomer concentration on the optical properties of electrochemically synthesized polypyrrole thin films

    International Nuclear Information System (INIS)

    Thombare, J. V.; Fulari, V. J.; Rath, M. C.; Han, S. H.

    2013-01-01

    Polypyrrole (PPy) thin films were deposited on stainless steel and ITO coated glass substrate at a constant deposition potential of 0.8 V versus saturated calomel electrode (SCE) by using the electrochemical polymerization method. The PPy thin films were deposited at room temperature at various monomer concentrations ranging from 0.1 M to 0.3 M pyrrole. The structural and optical properties of the polypyrrole thin films were investigated using an X-ray diffractometer (XRD), FTIR spectroscopy, scanning electron microscopy (SEM), and ultraviolet—visible (UV—vis) spectroscopy. The XRD results show that polypyrrole thin films have a semi crystalline structure. Higher monomer concentration results in a slight increase of crystallinity. The polypyrrole thin films deposited at higher monomer concentration exhibit high visible absorbance. The refractive indexes of the polypyrrole thin films are found to be in the range of 1 to 1.3 and vary with monomer concentration as well as wavelength. The extinction coefficient decreases slightly with monomer concentration. The electrochemically synthesized polypyrrole thin film shows optical band gap energy of 2.14 eV. (semiconductor materials)

  4. Measurements of Pfirsch-Schlueter current and pressure profile for the high density ECH plasmas in Heliotron DR

    International Nuclear Information System (INIS)

    Morimoto, S.; Yanagi, N.; Nakasuga, M.; Obiki, T.; Iiyoshi, A.; Uo, K.

    1988-01-01

    The Pfirsch-Schlueter current and pressure profiles are estimated from magnetic measurements for high density electron cyclotron heating (ECH) plasmas (n-bar e =(2-3)x10 13 cm -3 , T e0 =200-400 eV, (β) 0 (1-(r/a) 2 ) s , is about two in macroscopically stable plasmas. A fast loss of plasma energy from the centre to the periphery is observed during the onset of the MHD instability. This method of measuring the pressure profile shape is simple and useful for heliotron type devices. (author). 20 refs, 8 figs, 1 tab

  5. Improved thrombin binding aptamer by incorporation of a single unlocked nucleic acid monomer

    DEFF Research Database (Denmark)

    Pasternak, Anna; Hernandez, Frank J; Rasmussen, Lars Melholt

    2011-01-01

    A 15-mer DNA aptamer (named TBA) adopts a G-quadruplex structure that strongly inhibits fibrin-clot formation by binding to thrombin. We have performed thermodynamic analysis, binding affinity and biological activity studies of TBA variants modified by unlocked nucleic acid (UNA) monomers. UNA...... that a UNA monomer is allowed in many positions of the aptamer without significantly changing the thrombin-binding properties. The biological effect of a selection of the modified aptamers was tested by a thrombin time assay and showed that most of the UNA-modified TBAs possess anticoagulant properties......, and that the construct with a UNA-U monomer in position 7 is a highly potent inhibitor of fibrin-clot formation....

  6. High-speed atomic force microscopy reveals structural dynamics of α -synuclein monomers and dimers

    Science.gov (United States)

    Zhang, Yuliang; Hashemi, Mohtadin; Lv, Zhengjian; Williams, Benfeard; Popov, Konstantin I.; Dokholyan, Nikolay V.; Lyubchenko, Yuri L.

    2018-03-01

    α-Synuclein (α-syn) is the major component of the intraneuronal inclusions called Lewy bodies, which are the pathological hallmark of Parkinson's disease. α-Syn is capable of self-assembly into many different species, such as soluble oligomers and fibrils. Even though attempts to resolve the structures of the protein have been made, detailed understanding about the structures and their relationship with the different aggregation steps is lacking, which is of interest to provide insights into the pathogenic mechanism of Parkinson's disease. Here we report the structural flexibility of α-syn monomers and dimers in an aqueous solution environment as probed by single-molecule time-lapse high-speed AFM. In addition, we present the molecular basis for the structural transitions using discrete molecular dynamics (DMD) simulations. α-Syn monomers assume a globular conformation, which is capable of forming tail-like protrusions over dozens of seconds. Importantly, a globular monomer can adopt fully extended conformations. Dimers, on the other hand, are less dynamic and show a dumbbell conformation that experiences morphological changes over time. DMD simulations revealed that the α-syn monomer consists of several tightly packed small helices. The tail-like protrusions are also helical with a small β-sheet, acting as a "hinge". Monomers within dimers have a large interfacial interaction area and are stabilized by interactions in the non-amyloid central (NAC) regions. Furthermore, the dimer NAC-region of each α-syn monomer forms a β-rich segment. Moreover, NAC-regions are located in the hydrophobic core of the dimer.

  7. Density profile and cholesterol concentration of serum lipoproteins in experimental animals and human subjects on hypercholesterolaemic diets

    NARCIS (Netherlands)

    Beynen, A.C.; Terpstra, A.H.M.

    1984-01-01

    1. 1. The density profile of Sudan black stained serum lipoproteins was studied in human subjects and various animal species on diets supplemented with cholesterol. 2. 2. In the animals studied (rabbits, calves, mice, chickens, rats and guinea-pigs), the feeding of cholesterol resulted in an

  8. Considerably Unfolded Transthyretin Monomers Preceed and Exchange with Dynamically Structured Amyloid Protofibrils

    DEFF Research Database (Denmark)

    Groenning, Minna; Campos, Raul I; Hirschberg, Daniel

    2015-01-01

    describe an unexpectedly dynamic TTR protofibril structure which exchanges protomers with highly unfolded monomers in solution. The protofibrils only grow to an approximate final size of 2,900 kDa and a length of 70 nm and a comparative HXMS analysis of native and aggregated samples revealed a much higher...... average solvent exposure of TTR upon fibrillation. With SAXS, we reveal the continuous presence of a considerably unfolded TTR monomer throughout the fibrillation process, and show that a considerable fraction of the fibrillating protein remains in solution even at a late maturation state. Together......, these data reveal that the fibrillar state interchanges with the solution state. Accordingly, we suggest that TTR fibrillation proceeds via addition of considerably unfolded monomers, and the continuous presence of amyloidogenic structures near the protofibril surface offers a plausible explanation...

  9. In situ polymerization of monomers for polyphenylquinoxaline/graphite fiber composites

    Science.gov (United States)

    Serafini, T. T.; Delvigs, P.; Vannucci, R. D.

    1974-01-01

    Methods currently used to prepare fiber reinforced, high temperature resistant polyphenylquinoxaline (PPQ) composites employ extremely viscous, low solids content solutions of high molecular weight PPQ polymers. An improved approach, described in this report, consists of impregnating the fiber with a solution of the appropriate monomers instead of a solution of previously synthesized high molecular weight polymer. Polymerization of the monomers occurs in situ on the fiber during the solvent removal and curing stages. The in situ polymerization approach greatly simplifies the fabrication of PPQ graphite fiber composites. The use of low viscosity monomeric type solutions facilitates fiber wetting, permits a high solids content, and eliminates the need for prior polymer synthesis.

  10. Calculation of vibrational spectra for dioxouranium monochloride monomer and dimers

    Science.gov (United States)

    Umreiko, D. S.; Shundalau, M. B.; Zazhogin, A. P.; Komyak, A. I.

    2010-09-01

    Structural models were built and spectral characteristics were calculated based on ab initio calculations for the monomer and dimers of dioxouranium monochoride UO2Cl. The calculations were carried out in the effective core potential LANL2DZ approximation for the uranium atom and all-electron basis sets using DFT methods for oxygen and chlorine atoms (B3LYP/cc-pVDZ). The monomer UO2Cl was found to possess an equilibrium planar (close to T-shaped) configuration with C2v symmetry. The obtained spectral characteristics were analyzed and compared with experimental data. The adequacy of the proposed models and the qualitative agreement between calculation and experiment were demonstrated.

  11. High-Latitude Topside Ionospheric Vertical Electron-Density-Profile Changes in Response to Large Magnetic Storms

    Science.gov (United States)

    Benson, Robert F.; Fainberg, Joseph; Osherovich, Vladimir A.; Truhlik, Vladimir; Wang, Yongli; Bilitza, Dieter; Fung, Shing F.

    2015-01-01

    Large magnetic-storm induced changes have been detected in high-latitude topside vertical electron-density profiles Ne(h). The investigation was based on the large database of topside Ne(h) profiles and digital topside ionograms from the International Satellites for Ionospheric Studies (ISIS) program available from the NASA Space Physics Data Facility (SPDF) at http://spdf.gsfc.nasa.gov/isis/isis-status.html. This large database enabled Ne(h) profiles to be obtained when an ISIS satellite passed through nearly the same region of space before, during, and after a major magnetic storm. A major goal was to relate the magnetic-storm induced high-latitude Ne(h) profile changes to solar-wind parameters. Thus an additional data constraint was to consider only storms where solar-wind data were available from the NASA/SPDF OMNIWeb database. Ten large magnetic storms (with Dst less than -100 nT) were identified that satisfied both the Ne(h) profile and the solar-wind data constraints. During five of these storms topside ionospheric Ne(h) profiles were available in the high-latitude northern hemisphere and during the other five storms similar ionospheric data were available in the southern hemisphere. Large Ne(h) changes were observed during each one of these storms. Our concentration in this paper is on the northern hemisphere. The data coverage was best for the northern-hemisphere winter. Here Ne(h) profile enhancements were always observed when the magnetic local time (MLT) was between 00 and 03 and Ne(h) profile depletions were always observed between 08 and 10 MLT. The observed Ne(h) deviations were compared with solar-wind parameters, with appropriate time shifts, for four storms.

  12. Prediction of monomer reactivity in radical copolymerizations from transition state quantum chemical descriptors

    Directory of Open Access Journals (Sweden)

    Zhengde Tan

    2013-01-01

    Full Text Available In comparison with the Q-e scheme, the Revised Patterns Scheme: the U, V Version (the U-V scheme has greatly improved both its accessibility and its accuracy in interpreting and predicting the reactivity of a monomer in free-radical copolymerizations. Quantitative structure-activity relationship (QSAR models were developed to predict the reactivity parameters u and v of the U-V scheme, by applying genetic algorithm (GA and support vector machine (SVM techniques. Quantum chemical descriptors used for QSAR models were calculated from transition state species with structures C¹H3 - C²HR³• or •C¹H2 - C²H2R³ (formed from vinyl monomers C¹H²=C²HR³ + H•, using density functional theory (DFT, at the UB3LYP level of theory with 6-31G(d basis set. The optimum support vector regression (SVR model of the reactivity parameter u based on Gaussian radial basis function (RBF kernel (C = 10, ε = 10- 5 and γ = 1.0 produced root-mean-square (rms errors for the training, validation and prediction sets being 0.220, 0.326 and 0.345, respectively. The optimal SVR model for v with the RBF kernel (C = 20, ε = 10- 4 and γ = 1.2 produced rms errors for the training set of 0.123, the validation set of 0.206 and the prediction set of 0.238. The feasibility of applying the transition state quantum chemical descriptors to develop SVM models for reactivity parameters u and v in the U-V scheme has been demonstrated.

  13. Simultaneous Conduction and Valence Band Quantization in Ultrashallow High-Density Doping Profiles in Semiconductors

    Science.gov (United States)

    Mazzola, F.; Wells, J. W.; Pakpour-Tabrizi, A. C.; Jackman, R. B.; Thiagarajan, B.; Hofmann, Ph.; Miwa, J. A.

    2018-01-01

    We demonstrate simultaneous quantization of conduction band (CB) and valence band (VB) states in silicon using ultrashallow, high-density, phosphorus doping profiles (so-called Si:P δ layers). We show that, in addition to the well-known quantization of CB states within the dopant plane, the confinement of VB-derived states between the subsurface P dopant layer and the Si surface gives rise to a simultaneous quantization of VB states in this narrow region. We also show that the VB quantization can be explained using a simple particle-in-a-box model, and that the number and energy separation of the quantized VB states depend on the depth of the P dopant layer beneath the Si surface. Since the quantized CB states do not show a strong dependence on the dopant depth (but rather on the dopant density), it is straightforward to exhibit control over the properties of the quantized CB and VB states independently of each other by choosing the dopant density and depth accordingly, thus offering new possibilities for engineering quantum matter.

  14. Step Density Profiles in Localized Chains

    Science.gov (United States)

    De Roeck, Wojciech; Dhar, Abhishek; Huveneers, François; Schütz, Marius

    2017-06-01

    We consider two types of strongly disordered one-dimensional Hamiltonian systems coupled to baths (energy or particle reservoirs) at the boundaries: strongly disordered quantum spin chains and disordered classical harmonic oscillators. These systems are believed to exhibit localization, implying in particular that the conductivity decays exponentially in the chain length L. We ask however for the profile of the (very slowly) transported quantity in the steady state. We find that this profile is a step-function, jumping in the middle of the chain from the value set by the left bath to the value set by the right bath. This is confirmed by numerics on a disordered quantum spin chain of 9 spins and on much longer chains of harmonic oscillators. From theoretical arguments, we find that the width of the step grows not faster than √{L}, and we confirm this numerically for harmonic oscillators. In this case, we also observe a drastic breakdown of local equilibrium at the step, resulting in a heavily oscillating temperature profile.

  15. Latent Profiles of Macronutrient Density and their Association with Mobility Limitations in an Observational Longitudinal Study of Older U.S. Adults.

    Science.gov (United States)

    Bishop, N J; Zuniga, K E; Lucht, A L

    2018-01-01

    Our first objective was to estimate empirically-derived subgroups (latent profiles) of observed carbohydrate, protein, and fat intake density in a nationally representative sample of older U.S. adults. Our second objective was to determine whether membership in these groups was associated with levels of, and short term change in, physical mobility limitations. Measures of macronutrient density were taken from the 2013 Health Care and Nutrition Study, an off-year supplement to the Health and Retirement Study, which provided indicators of physical mobility limitations and sociodemographic and health-related covariates. 3,914 community-dwelling adults age 65 years and older. Percent of daily calories from carbohydrate, protein, and fat were calculated based on responses to a modified Harvard food frequency questionnaire. Latent profile analysis was used to describe unobserved heterogeneity in measures of carbohydrate, protein, and fat density. Mobility limitation counts were based on responses to 11 items indicating physical limitations. Poisson regression models with autoregressive controls were used to identify associations between macronutrient density profile membership and mobility limitations. Sociodemographic and health-related covariates were included in all Poisson regression models. Four latent subgroups of macronutrient density were identified: "High Carbohydrate", "Moderate with Fat", "Moderate", and "Low Carbohydrate/High Fat". Older adults with the lowest percentage of daily calories coming from carbohydrate and the greatest percentage coming from fat ("Low Carbohydrate/High Fat") were found to have greater reported mobility limitations in 2014 than those identified as having moderate macronutrient density, and more rapid two-year increases in mobility limitations than those identified as "Moderate with Fat" or "Moderate". Older adults identified as having the lowest carbohydrate and highest fat energy density were more likely to report a greater number

  16. Monomer-dimer problem on random planar honeycomb lattice

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Haizhen [School of Mathematical Sciences, Xiamen University, Xiamen 361005, Fujian (China); Department of Mathematics, Qinghai Normal University, Xining 810008, Qinghai (China); Zhang, Fuji; Qian, Jianguo, E-mail: jqqian@xmu.edu.cn [School of Mathematical Sciences, Xiamen University, Xiamen 361005, Fujian (China)

    2014-02-15

    We consider the monomer-dimer (MD) problem on a random planar honeycomb lattice model, namely, the random multiple chain. This is a lattice system with non-periodic boundary condition, whose generating process is inspired by the growth of single walled zigzag carbon nanotubes. By applying algebraic and combinatorial techniques we establish a calculating expression of the MD partition function for bipartite graphs, which corresponds to the permanent of a matrix. Further, by using the transfer matrix argument we show that the computing problem of the permanent of high order matrix can be converted into some lower order matrices for this family of lattices, based on which we derive an explicit recurrence formula for evaluating the MD partition function of multiple chains and random multiple chains. Finally, we analyze the expectation of the number of monomer-dimer arrangements on a random multiple chain and the asymptotic behavior of the annealed MD entropy when the multiple chain becomes infinite in width and length, respectively.

  17. Anisotropy of the monomer random walk in a polymer melt: local-order and connectivity effects

    International Nuclear Information System (INIS)

    Bernini, S; Leporini, D

    2016-01-01

    The random walk of a bonded monomer in a polymer melt is anisotropic due to local order and bond connectivity. We investigate both effects by molecular-dynamics simulations on melts of fully-flexible linear chains ranging from dimers (M  =  2) up to entangled polymers (M  =  200). The corresponding atomic liquid is also considered a reference system. To disentangle the influence of the local geometry and the bond arrangements, and to reveal their interplay, we define suitable measures of the anisotropy emphasising either the former or the latter aspect. Connectivity anisotropy, as measured by the correlation between the initial bond orientation and the direction of the subsequent monomer displacement, shows a slight enhancement due to the local order at times shorter than the structural relaxation time. At intermediate times—when the monomer displacement is comparable to the bond length—a pronounced peak and then decays slowly as t −1/2 , becoming negligible when the displacement is as large as about five bond lengths, i.e. about four monomer diameters or three Kuhn lengths. Local-geometry anisotropy, as measured by the correlation between the initial orientation of a characteristic axis of the Voronoi cell and the subsequent monomer dynamics, is affected at shorter times than the structural relaxation time by the cage shape with antagonistic disturbance by the connectivity. Differently, at longer times, the connectivity favours the persistence of the local-geometry anisotropy, which vanishes when the monomer displacement exceeds the bond length. Our results strongly suggest that the sole consideration of the local order is not enough to understand the microscopic origin of the rattling amplitude of the trapped monomer in the cage of the neighbours. (paper)

  18. Measurements of Laser Plasma Instability (LPI) and Electron Density/Temperature Profiles in Plasmas Produced by the Nike KrF Laser

    Science.gov (United States)

    Oh, Jaechul; Weaver, J. L.; Serlin, V.; Obenschain, S. P.

    2016-10-01

    We will present results of simultaneous measurements of LPI-driven light scattering and density/temperature profiles in CH plasmas produced by the Nike krypton fluoride laser (λ = 248 nm). The primary diagnostics for the LPI measurement are time-resolved spectrometers with absolute intensity calibration in spectral ranges relevant to the optical detection of stimulated Raman scattering or two plasmon decay. The spectrometers are capable of monitoring signal intensity relative to thermal background radiation from plasma providing a useful way to analyze LPI initiation. For further understanding of LPI processes, the recently implemented grid image refractometer (Nike-GIR)a is used to measure the coronal plasma profiles. In this experiment, Nike-GIR is equipped with a 5th harmonic probe laser (λ = 213 nm) in attempt to probe into a high density region over the previous peak density with λ = 263 nm probe light ( 4 ×1021 cm-3). The LPI behaviors will be discussed with the measured data sets. Work supported by DoE/NNSA.

  19. Measurements of electron density and temperature profiles in plasma produced by Nike KrF laser for laser plasma instability research

    Science.gov (United States)

    Oh, Jaechul; Weaver, J. L.; Karasik, M.; Chan, L. Y.

    2015-08-01

    A grid image refractometer (GIR) has been implemented at the Nike krypton fluoride laser facility of the Naval Research Laboratory. This instrument simultaneously measures propagation angles and transmissions of UV probe rays (λ = 263 nm, Δt = 10 ps) refracted through plasma. We report results of the first Nike-GIR measurement on a CH plasma produced by the Nike laser pulse (˜1 ns FWHM) with the intensity of 1.1 × 1015 W/cm2. The measured angles and transmissions were processed to construct spatial profiles of electron density (ne) and temperature (Te) in the underdense coronal region of the plasma. Using an inversion algorithm developed for the strongly refracted rays, the deployed GIR system probed electron densities up to 4 × 1021 cm-3 with the density scale length of 120 μm along the plasma symmetry axis. The resulting ne and Te profiles are verified to be self-consistent with the measured quantities of the refracted probe light.

  20. Measurement of deuterium density profiles in the H-mode steep gradient region using charge exchange recombination spectroscopy on DIII-D.

    Science.gov (United States)

    Haskey, S R; Grierson, B A; Burrell, K H; Chrystal, C; Groebner, R J; Kaplan, D H; Pablant, N A; Stagner, L

    2016-11-01

    Recent completion of a thirty two channel main-ion (deuterium) charge exchange recombination spectroscopy (CER) diagnostic on the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] enables detailed comparisons between impurity and main-ion temperature, density, and toroidal rotation. In a H-mode DIII-D discharge, these new measurement capabilities are used to provide the deuterium density profile, demonstrate the importance of profile alignment between Thomson scattering and CER diagnostics, and aid in determining the electron temperature at the separatrix. Sixteen sightlines cover the core of the plasma and another sixteen are densely packed towards the plasma edge, providing high resolution measurements across the pedestal and steep gradient region in H-mode plasmas. Extracting useful physical quantities such as deuterium density is challenging due to multiple photoemission processes. These challenges are overcome using a detailed fitting model and by forward modeling the photoemission using the FIDASIM code, which implements a comprehensive collisional radiative model.

  1. Low-temperature radiation-induced polymerization of vinyl monomers in the crystal matrix of polydimethyl siloxane

    International Nuclear Information System (INIS)

    Mujdinov, M.R.; Kiryukhin, D.P.; Barkalov, I.M.; Gol'danskij, V.I.

    1979-01-01

    It is shown that in the process of the slow cooling of vinyl monomer solution in dimethyl siloxane rubber (SKT mark) crystallization of SKT takes place, at that, considerable part of vinyl monomers (up to 70 wt. % of rubber) is sorbed in the pores of crystal matrix and it does not form its proper crystal phase. Slight anomalies in heat capacity in the 120-140 K range, the melting of non-sorbed part of MA and the melting of SKT + MA ''complex'' have been observed on the calorimetric curve at the SKT - methylacrylate (MA) system heating. In the process of heating such samples, irradiated at 77 K by γ-rays of 60 Co, heat evolution connected with sorbed monomer polarization, has been observed starting from 125-130 K. In the 140-200 K range already before MA and SKT melting intense polymerization takes place, which results in practically full monomer consumption and formation of graft copolymer. Radiation-chemical yield of monomer reduction reaches G(-M) approximately equal to 2x10 5 molecules for 100 eV, radiation yield of postpolymerization of crystal MA does not exceed G(-M) approximately equal to 50 molecules for 100 eV

  2. Study on grafting of different types of acrylic monomers onto natural rubber by γ-rays

    International Nuclear Information System (INIS)

    Dafader, N.C.; Haque, M.E.; Akhtar, F.; Ahmad, M.U.

    2006-01-01

    A comparative study of various acrylic monomers for grafting onto natural rubber was done. The stability of natural rubber latex (NRL) against coagulum with monomer, mechanical properties of grafted rubbers and percent of grafting were investigated. The NRL with monomers, methylacrylate (MA), ethylacrylate (EA) and n-butylacrylate (n-BA), is unstable but it is stable with methyl methacrylate (MMA), n-butyl methacrylate (BMA) and cyclohexyl methacrylate (CHMA). The mechanical properties and degree of grafting attained a maximum at a total radiation dose of 4 kGy. The values of tensile properties of MMA and CHMA grafted rubbers are almost similar, and higher than those of BMA grafted rubbers. On the other hand, the degree of grafting for CHMA is higher than those of MMA and BMA grafted rubbers. The infrared (IR) spectra of monomer grafted natural rubber were also studied

  3. Effect of reactive monomer on PS-b-P2VP film.

    Science.gov (United States)

    Kim, H J; Shin, D M

    2014-08-01

    Poly(styrene-b-2-vinyl pyridine) (PS-b-P2VP) lamellar film which is hydrophobic block-hydrophilic polyelectrolyte block polymer of 52 kg/mol-b-57 kg/mol and PS-b-P2VP film with reactive monomer (RM257) were prepared for photonic gel films. The lamellar stacks, which is alternating layer of hydrophilic and hydrophobic moiety of PS-b-P2VP, were obtained by exposing the spin coated film under chloroform vapor. The lamellar films were quaternized with 5 wt% of iodomethane diluted by n-hexane. We reported about the influence of reactive monomer on those photonic gel films. Added reactive monomer photonic gel film had higher absorbance than pure photonic gel films. As a result the photonic gel film with RM had more clear color. The lamellar films were swollen by DI water, ethanol (aq) and calcium carbonate solution. The band gaps of the lamellar films were drastically shifted to longer wavelength swollen by calcium carbonate solution. And the lamellar films were shifted to shorter wave length swollen by ethanol. So each lamellar film showed different color.

  4. Hydrophobic Coatings on Cotton Obtained by in Situ Plasma Polymerization of a Fluorinated Monomer in Ethanol Solutions.

    Science.gov (United States)

    Molina, Ricardo; Teixidó, Josep Maria; Kan, Chi-Wai; Jovančić, Petar

    2017-02-15

    Plasma polymerization using hydrophobic monomers in the gas phase is a well-known technology to generate hydrophobic coatings. However, synthesis of functional hydrophobic coatings using plasma technology in liquids has not yet been accomplished. This work is consequently focused on polymerization of a liquid fluorinated monomer on cotton fabric initiated by atmospheric plasma in a dielectric barrier discharge configuration. Functional hydrophobic coatings on cotton were successfully achieved using in situ atmospheric plasma-initiated polymerization of fluorinated monomer dissolved in ethanol. Gravimetric measurements reveal that the amount of polymer deposited on cotton substrates can be modulated with the concentration of monomer in ethanol solution, and cross-linking reactions occur during plasma polymerization of a fluorinated monomer even without the presence of a cross-linking agent. FTIR and XPS analysis were used to study the chemical composition of hydrophobic coatings and to get insights into the physicochemical processes involved in plasma treatment. SEM analysis reveals that at high monomer concentration, coatings possess a three-dimensional pattern with a characteristic interconnected porous network structure. EDX analysis reveals that plasma polymerization of fluorinated monomers takes place preferentially at the surface of cotton fabric and negligible polymerization takes place inside the cotton fabric. Wetting time measurements confirm the hydrophobicity of cotton coatings obtained although equilibrium moisture content was slightly decreased. Additionally, the abrasion behavior and resistance to washing of plasma-coated cotton has been evaluated.

  5. 21 CFR 864.7300 - Fibrin monomer paracoagulation test.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Fibrin monomer paracoagulation test. 864.7300 Section 864.7300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7300 Fibrin...

  6. Finding evidence for density fluctuation effects on electron cyclotron heating deposition profiles on DIII-D

    International Nuclear Information System (INIS)

    Brookman, M. W.; Austin, M. E.; Petty, C. C.

    2015-01-01

    Theoretical work, computation, and results from TCV [J. Decker “Effect of density fluctuations on ECCD in ITER and TCV,” EPJ Web of Conf. 32, 01016 (2012)] suggest that density fluctuations in the edge region of a tokamak plasma can cause broadening of the ECH deposition profile. In this paper, a GUI tool is presented which is used for analysis of ECH deposition as a first step towards looking for this broadening, which could explain effects seen in previous DIII-D ECH transport studies [K.W. Gentle “Electron energy transport inferences from modulated electron cyclotron heating in DIII-D,” Phys. Plasmas 13, 012311 (2006)]. By applying an FFT to the T e measurements from the University of Texas’s 40-channel ECE Radiometer, and using a simplified thermal transport equation, the flux surface extent of ECH deposition is determined. The Fourier method analysis is compared with a Break-In-Slope (BIS) analysis and predictions from the ray-tracing code TORAY. Examination of multiple Fourier harmonics and BIS fitting methods allow an estimation of modulated transport coefficients and thereby the true ECH deposition profile. Correlations between edge fluctuations and ECH deposition in legacy data are also explored as a step towards establishing a link between fluctuations and deposition broadening in DIII-D

  7. Finding evidence for density fluctuation effects on electron cyclotron heating deposition profiles on DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Brookman, M. W., E-mail: brookmanmw@fusion.gat.com; Austin, M. E. [Institute for Fusion Studies, University of Texas at Austin, MS 13-505, 3483 Dunhill St, San Diego, CA 92121-1200 (United States); Petty, C. C. [General Atomics, PO Box 85608, San Diego, CA 92186-5608 (United States)

    2015-12-10

    Theoretical work, computation, and results from TCV [J. Decker “Effect of density fluctuations on ECCD in ITER and TCV,” EPJ Web of Conf. 32, 01016 (2012)] suggest that density fluctuations in the edge region of a tokamak plasma can cause broadening of the ECH deposition profile. In this paper, a GUI tool is presented which is used for analysis of ECH deposition as a first step towards looking for this broadening, which could explain effects seen in previous DIII-D ECH transport studies [K.W. Gentle “Electron energy transport inferences from modulated electron cyclotron heating in DIII-D,” Phys. Plasmas 13, 012311 (2006)]. By applying an FFT to the T{sub e} measurements from the University of Texas’s 40-channel ECE Radiometer, and using a simplified thermal transport equation, the flux surface extent of ECH deposition is determined. The Fourier method analysis is compared with a Break-In-Slope (BIS) analysis and predictions from the ray-tracing code TORAY. Examination of multiple Fourier harmonics and BIS fitting methods allow an estimation of modulated transport coefficients and thereby the true ECH deposition profile. Correlations between edge fluctuations and ECH deposition in legacy data are also explored as a step towards establishing a link between fluctuations and deposition broadening in DIII-D.

  8. Negative Ion Density Fronts

    International Nuclear Information System (INIS)

    Igor Kaganovich

    2000-01-01

    Negative ions tend to stratify in electronegative plasmas with hot electrons (electron temperature Te much larger than ion temperature Ti, Te > Ti ). The boundary separating a plasma containing negative ions, and a plasma, without negative ions, is usually thin, so that the negative ion density falls rapidly to zero-forming a negative ion density front. We review theoretical, experimental and numerical results giving the spatio-temporal evolution of negative ion density fronts during plasma ignition, the steady state, and extinction (afterglow). During plasma ignition, negative ion fronts are the result of the break of smooth plasma density profiles during nonlinear convection. In a steady-state plasma, the fronts are boundary layers with steepening of ion density profiles due to nonlinear convection also. But during plasma extinction, the ion fronts are of a completely different nature. Negative ions diffuse freely in the plasma core (no convection), whereas the negative ion front propagates towards the chamber walls with a nearly constant velocity. The concept of fronts turns out to be very effective in analysis of plasma density profile evolution in strongly non-isothermal plasmas

  9. A gravity study along a profile across the Sichuan Basin, the Qinling Mountains and the Ordos Basin (central China): Density, isostasy and dynamics

    Science.gov (United States)

    Zhang, Yongqian; Teng, Jiwen; Wang, Qianshen; Lü, Qingtian; Si, Xiang; Xu, Tao; Badal, José; Yan, Jiayong; Hao, Zhaobing

    2017-10-01

    In order to investigate the structure of the crust beneath the Middle Qinling Mountains (MQL) and neighboring areas in the North China Block and South China Block, a north-south gravity profile from Yuquan in the Sichuan Basin to Yulin in the Ordos Basin was conducted in 2011. The Bouguer gravity anomaly is determined from a high-quality gravity dataset collected between 31°N and 36°N of latitude, and varies between -200 and -110 mGal in the study region. Using accredited velocity density relationships, an initial crust-mantle density model is constructed for MQL and adjacent areas, which is later refined interactively to simulate the observed gravity anomaly. The present study reveals the features of the density and Bouguer gravity with respect to the tectonic units sampled by the profile. The lithosphere density model shows typical density values that depict a layered structure and allow differentiate the blocks that extend along the reference profile. The gravity field calculated by forward modeling from the final density distribution model correlates well with the measured gravity field within a standard deviation of 1.26 mGal. The density in the crystalline crust increases with depth from 2.65 g/cm3 up to the highest value of 2.95 g/cm3 near the bottom of the crust. The Conrad interface is identified as a density jump of about 0.05 g/cm3. The average density of the crust in MQL is clearly lower than the density in the formations on both sides. Starting from a combined Airy-Pratt isostatic compensation model, a partly compensated crust is found below MQL, suggesting future growth of the crust, unlike the Ordos and Sichuan basins that will remain stable. On the basis of the density and isostatic state of the crust and additional seismological research, such as the P-wave velocity model and Poisson's ratio, it is concluded that the lower crust delamination is a reasonable interpretation for the geophysical characteristics below the Qinling Orogen.

  10. FT-IR, FT-Raman, NMR spectra, density functional computations of the vibrational assignments (for monomer and dimer) and molecular geometry of anticancer drug 7-amino-2-methylchromone

    Science.gov (United States)

    Mariappan, G.; Sundaraganesan, N.

    2014-04-01

    Vibrational assignments for the 7-amino-2-methylchromone (abbreviated as 7A2MC) molecule using a combination of experimental vibrational spectroscopic measurements and ab initio computational methods are reported. The optimized geometry, intermolecular hydrogen bonding, first order hyperpolarizability and harmonic vibrational wavenumbers of 7A2MC have been investigated with the help of B3LYP density functional theory method. The calculated molecular geometry parameters, the theoretically computed vibrational frequencies for monomer and dimer and relative peak intensities were compared with experimental data. DFT calculations using the B3LYP method and 6-31 + G(d,p) basis set were found to yield results that are very comparable to experimental IR and Raman spectra. Detailed vibrational assignments were performed with DFT calculations and the potential energy distribution (PED) obtained from the Vibrational Energy Distribution Analysis (VEDA) program. Natural Bond Orbital (NBO) study revealed the characteristics of the electronic delocalization of the molecular structure. 13C and 1H NMR spectra have been recorded and 13C and 1H nuclear magnetic resonance chemical shifts of the molecule have been calculated using the gauge independent atomic orbital (GIAO) method. Furthermore, All the possible calculated values are analyzed using correlation coefficients linear fitting equation and are shown strong correlation with the experimental data.

  11. Effect of Laser-assisted and Conventional In-office Bleaching on Monomer Release from Microhybrid and Nanohybrid Composite.

    Science.gov (United States)

    Omrani, Ladan Ranjbar; Farjadfar, Shayan; Pedram, Parham; Sadray, Sima; Kamangar, Sedighe Sadat Hashemi; Chiniforoush, Nasim

    2017-06-30

    Bleaching might affect structural properties of composite materials, and lead to monomer release. This study aimed to evaluate the effect of Laser-assisted and conventional in-office bleaching on the release of BIS-GMA, TEGDMA, and UDMA monomers from a nanohybrid and a microhybrid BIS-GMA based composite. 32 samples of each composite, were divided into 4 subgroups; subgroup 1: Conventional in-office bleaching (CIB) with the Opalescence Boost PF 38% gel, subgroup 2: Laser-assisted bleaching (LBO) with the Opalescence Boost PF 38% gel, subgroup 3: Laser-assisted bleaching (LBH) with the JW Power bleaching gel, subgroup 4: (CO) control without bleaching. All the samples were immersed in tubes of 2cc Ethanol 75% medium. The released monomers were analyzed using the high performance liquid chromatography (HPLC) method 24 h, 7, and 28 days. Data's were analyzed by Univariate Analysis of Variance test followed by Tukeys HSD. The amount of TEGDMA monomer released was not significant. However, nanohybrid composites showed significantly more monomer release than microhybrid composites (P Bleaching by laser with JW Power Bleaching gel led to more monomer release in nanohybrid composite.

  12. Characterisation of polyhydroxyalkanoate copolymers with controllable four-monomer composition.

    Science.gov (United States)

    Dai, Yu; Lambert, Lynette; Yuan, Zhiguo; Keller, Jurg

    2008-03-20

    Polyhydroxyalkanoate (PHA) copolymers comprising the four monomers 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), 3-hydroxy-2-methylvalerate (3HMV) and 3-hydroxy-2-methylbutyrate (3HMB) were generated using the recently discovered Defluviicoccus vanus-related glycogen accumulating organisms (DvGAOs) under anaerobic conditions without applying any nutrient limitations. The composition could be manipulated in a defined range by modifying the ratio of propionate and acetate provided in the feed stream. The PHAs produced were characterised as random copolymers (from propionate alone) or a mixture of random copolymers (from mixture of propionate and acetate) through microstructure analysis using 13C NMR spectroscopy. The sequence distribution of all eight comonomer pairs in the carbonyl region of 3HB and 3HV was identified and assigned with confidence utilising two-dimensional heteronuclear multiple bond coherence (HMBC) spectroscopy. Weight average molecular weights were in the range 390-560 kg/mol. Differential scanning calorimetry (DSC) traces showed that the melting temperature (Tm) varied between 70 and 161 degrees C and glass transition temperature (Tg) ranged from -8 to 0 degrees C. The incorporation of considerable amounts of 3HMV and 3HMB monomer units introduced additional "defects" into the PHBV copolymer structure and hence greatly lowered the crystallinity. The data indicate the potential of these four-monomer PHAs to be employed for practical applications, considering their favourable properties and the cost-effective production process using a mixed culture and simple carbon sources.

  13. Design and Applications of Biodegradable Polyester Tissue Scaffolds Based on Endogenous Monomers Found in Human Metabolism

    Directory of Open Access Journals (Sweden)

    Devin G. Barrett

    2009-10-01

    Full Text Available Synthetic polyesters have deeply impacted various biomedical and engineering fields, such as tissue scaffolding and therapeutic delivery. Currently, many applications involving polyesters are being explored with polymers derived from monomers that are endogenous to the human metabolism. Examples of these monomers include glycerol, xylitol, sorbitol, and lactic, sebacic, citric, succinic, α-ketoglutaric, and fumaric acids. In terms of mechanical versatility, crystallinity, hydrophobicity, and biocompatibility, polyesters synthesized partially or completely from these monomers can display a wide range of properties. The flexibility in these macromolecular properties allows for materials to be tailored according to the needs of a particular application. Along with the presence of natural monomers that allows for a high probability of biocompatibility, there is also an added benefit that this class of polyesters is more environmentally friendly than many other materials used in biomedical engineering. While the selection of monomers may be limited by nature, these polymers have produced or have the potential to produce an enormous number of successes in vitro and in vivo.

  14. Distinct Internalization Pathways of Human Amylin Monomers and Its Cytotoxic Oligomers in Pancreatic Cells

    Science.gov (United States)

    Trikha, Saurabh; Jeremic, Aleksandar M.

    2013-01-01

    Toxic human amylin oligomers and aggregates are implicated in the pathogenesis of type 2 diabetes mellitus (TTDM). Although recent studies have shown that pancreatic cells can recycle amylin monomers and toxic oligomers, the exact uptake mechanism and trafficking routes of these molecular forms and their significance for amylin toxicity are yet to be determined. Using pancreatic rat insulinoma (RIN-m5F) beta (β)-cells and human islets as model systems we show that monomers and oligomers cross the plasma membrane (PM) through both endocytotic and non-endocytotic (translocation) mechanisms, the predominance of which is dependent on amylin concentrations and incubation times. At low (≤100 nM) concentrations, internalization of amylin monomers in pancreatic cells is completely blocked by the selective amylin-receptor (AM-R) antagonist, AC-187, indicating an AM-R dependent mechanism. In contrast at cytotoxic (µM) concentrations monomers initially (1 hour) enter pancreatic cells by two distinct mechanisms: translocation and macropinocytosis. However, during the late stage (24 hours) monomers internalize by a clathrin-dependent but AM-R and macropinocytotic independent pathway. Like monomers a small fraction of the oligomers initially enter cells by a non-endocytotic mechanism. In contrast a majority of the oligomers at both early (1 hour) and late times (24 hours) traffic with a fluid-phase marker, dextran, to the same endocytotic compartments, the uptake of which is blocked by potent macropinocytotic inhibitors. This led to a significant increase in extra-cellular PM accumulation, in turn potentiating amylin toxicity in pancreatic cells. Our studies suggest that macropinocytosis is a major but not the only clearance mechanism for both amylin’s molecular forms, thereby serving a cyto-protective role in these cells. PMID:24019897

  15. Modelling of the electron density height profiles in the mid-latitude ionospheric D-region

    Directory of Open Access Journals (Sweden)

    P. Y. Mukhtarov

    1996-06-01

    Full Text Available A new mid-latitude D-region (50-105 km model of the electron density is presented obtained on the basis of a full wave theory and by a trial-and-error inversion method. Daytime (at different solar zenith angles absorption measurements by A3-technique made in Bulgaria yielded data with the aid of which the seasonal and diurnal courses of the Ne(h-profiles were derived. Special attention is drawn to the event diurnal asymmetry, or uneven formation of the ionosphere as a function of insulation. The latter is probably connected with the influence of the diurnal fluctuations in the local temperature on the chemistry involved in the electron loss rate, as well as the diurnal variations of the main ionizing agent (NO in the D-region. That is why the Ne(h-profiles in the midlatitude D-region are modelled separately for morning and afternoon hours.

  16. Conformationally locked aryl C-nucleosides: synthesis of phosphoramidite monomers and incorporation into single-stranded DNA and LNA (locked nucleic acid)

    DEFF Research Database (Denmark)

    Babu, B. Ravindra; Prasad, Ashok K.; Trikha, Smriti

    2002-01-01

    . The phosphoramidite approach was used for automated incorporation of the LNA-type beta-configured C-aryl monomers 17a-17e into short DNA and 2'-OMe-RNA/LNA strands. It is shown that universal hybridization can be obtained with a conformationally restricted monomer as demonstrated most convincingly for the pyrene LNA...... monomer 17d, both in a DNA context and in an RNA-like context. Increased binding affinity of oligonucleotide probes for universal hybridization can be induced by combining the pyrene LNA monomer 17d with affinity-enhancing 2'-OMe-RNA/LNA monomers....

  17. Modulation of i-motif thermodynamic stability by the introduction of UNA (unlocked nucleic acid) monomers

    DEFF Research Database (Denmark)

    Pasternak, Anna; Wengel, Jesper

    2011-01-01

    The influence of acyclic RNA derivatives, UNA (unlocked nucleic acid) monomers, on i-DNA thermodynamic stability has been investigated. The 22 nt human telomeric fragment was chosen as the model sequence for stability studies. UNA monomers modulate i-motif stability in a position-depending manner...

  18. Graft copolymers of polyurethane with various vinyl monomers via radiation-induced miniemulsion polymerization: Influential factors to grafting efficiency and particle morphology

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hua [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China); Wang Mozhen [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China)], E-mail: pstwmz@ustc.edu.cn; Ge Xuewu [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China)], E-mail: xwge@ustc.edu.cn

    2009-02-15

    Graft copolymers of polyurethane (PU) with various vinyl monomers were synthesized through a one-pot but two-step miniemulsion polymerization process. Firstly, the polycondensation of isophorone diisocyanate (IPDI) with hydroxyl-terminated polybutadiene (HTPB) had been performed in aqueous miniemulsion at 40 deg. C in order to obtain PU dispersions. Consecutively, an in-situ graft copolymerization of the vinyl monomers with the synthesized PU was initiated by {gamma}-ray radiation at room temperature. The grafting efficiency of PU with vinyl monomer (G{sub PU/monomer}) was calculated from {sup 1}H NMR spectra and the particle morphology of the final hybrid latex was observed by transmission electron microscopy (TEM). As there was no monomer transferring in miniemulsion system, homogenous hybrid particles would be synthesized provided that the monomer was miscible with PU, such as styrene. With the increase of the polarity of the monomer, the compatibility of PU with monomer decreased. G{sub PU/monomer} varied as G{sub PU/styrene}(37%)>G{sub PU/butyl} {sub acrylate} {sub (BA)}(21%)>G{sub PU/methyl} {sub methacrylate} {sub (MMA)}(12%). The proportion of homogeneous nucleation would increase as the hydrophilicity of the monomer increased. High temperature would destabilize the miniemulsion so as to result in a less grafting efficiency. Compared to the phase separation during the seeded emulsion polymerization, the miniemulsion polymerization method facilitated the preparation of homogeneous materials owing to its monomer droplet nucleation mechanism.

  19. Penelitian penggunaan monomer n-butil akrilat untuk peningkatan mutu kulit secara iradiasi

    OpenAIRE

    Dwi Wahini Nurhajati; Suliestiyah Wiryodiningrat; Kadarijah Kadarijah; Penny Setyowati

    1996-01-01

    Research on the utilization of n-butyl acrylate monomer for quality improvement leather by irradiation cobalt-60 gamma-rays is carried out as follows: Javanese crust hide was impregnated with water emulsions of n-butyl acrylate monomer for 2 hours, packed in to poly ethylene bags, sealed, then irradiated by cobalt-60 gamma rays (doses : 5 to 25 kGy). The irradiated leather was washed by water, dried and then physical tested. The results of physical test of leather modified with n-butyl acryl...

  20. Measuring the stellar luminosity function and spatial density profile of the inner 0.5 pc of the Milky Way nuclear star cluster

    Science.gov (United States)

    Do, Tuan; Ghez, Andrea; Lu, Jessica R.; Morris, Mark R.; Yelda, Sylvana; Martinez, Gregory D.; Peter, Annika H. G.; Wright, Shelley; Bullock, James; Kaplinghat, Manoj; Matthews, K.

    2012-07-01

    We report on measurements of the luminosity function of early (young) and late-type (old) stars in the central 0.5 pc of the Milky Way nuclear star cluster as well as the density profiles of both components. The young (~ 6 Myr) and old stars (> 1 Gyr) in this region provide different physical probes of the environment around a supermassive black hole; the luminosity function of the young stars offers us a way to measure the initial mass function from star formation in an extreme environment, while the density profile of the old stars offers us a probe of the dynamical interaction of a star cluster with a massive black hole. The two stellar populations are separated through a near-infrared spectroscopic survey using the integral-field spectrograph OSIRIS on Keck II behind the laser guide star adaptive optics system. This spectroscopic survey is able to separate early-type (young) and late-type (old) stars with a completeness of 50% at K' = 15.5. We describe our method of completeness correction using a combination of star planting simulations and Bayesian inference. The completeness corrected luminosity function of the early-type stars contains significantly more young stars at faint magnitudes compared to previous surveys with similar depth. In addition, by using proper motion and radial velocity measurements along with anisotropic spherical Jeans modeling of the cluster, it is possible to measure the spatial density profile of the old stars, which has been difficult to constrain with number counts alone. The most probable model shows that the spatial density profile, n(r) propto r-γ, to be shallow with γ = 0.4 ± 0.2, which is much flatter than the dynamically relaxed case of γ = 3/2 to 7/4, but does rule out a 'hole' in the distribution of old stars. We show, for the first time, that the spatial density profile, the black hole mass, and velocity anisotropy can be fit simultaneously to obtain a black hole mass that is consistent with that derived from

  1. A study on radiation-induced graft copolymerization of monomer onto natural silk fabric

    International Nuclear Information System (INIS)

    Xiang Zhengyu; Wan Dairong; He Qian

    1995-02-01

    In order to improve the properties of natural silk fabric, the mechanism and method of the radiation induced graft copolymerization of monomers onto natural silk fabric were studied. Three monomers, acrylamide, methylacrylamide and hydroxymethyl acrylamide, were selected for grafting test according to requirements of graft processing. The processing conditions of monomer infusion were studied. The properties of grafted samples were measured. The results are as follows: the rate of weight increasing is 10%∼29%; the rate of thickness increasing is 5%∼20%; the abrupt elasticity rose by 30%; the retarded elasticity rose by 12%; wet elasticity rose by 40%; and the brightness of colour and lustre were improved. It is concluded that while the radiation grafted silk kept its natural characteristics, other properties were improved. It became even chubby and thicker. (4 refs., 3 figs., 3 tabs.)

  2. Radiation crosslinking of PVC with polyfunctional monomers

    International Nuclear Information System (INIS)

    Dobo, J.; Takacs, E.; Csato, P.

    1984-01-01

    The radiation crosslinking of PVC in the presence of ethylene glycol dimethacrylate (EGDM) and of trimethylol propane trimethacrylate (TMPTM) was investigated. The effect of PVC powders of different types on the polymerization rate of these monomers was studied by a Calvet-type microcalorimeter. In the milled PVC sheets containing 50 part EGDM a high concentration of trapped free radicals was found by ESR after 16 months storage. (author)

  3. Solid-support Electron Paramagnetic Resonance (EPR) Studies of Aβ40 Monomers Reveal a Structured State with Three Ordered Segments*

    Science.gov (United States)

    Gu, Lei; Ngo, Sam; Guo, Zhefeng

    2012-01-01

    Alzheimer disease is associated with the pathological accumulation of amyloid-β peptide (Aβ) in the brain. Soluble Aβ oligomers formed during early aggregation process are believed to be neurotoxins and causative agents in Alzheimer disease. Aβ monomer is the building block for amyloid assemblies. A comprehensive understanding of the structural features of Aβ monomer is crucial for delineating the mechanism of Aβ oligomerization. Here we investigated the structures of Aβ40 monomer using a solid-support approach, in which Aβ40 monomers are tethered on the solid support via an N-terminal His tag to prevent further aggregation. EPR spectra of tethered Aβ40 with spin labels at 18 different positions show that Aβ40 monomers adopt a completely disordered structure under denaturing conditions. Under native conditions, however, EPR spectra suggest that Aβ40 monomers adopt both a disordered state and a structured state. The structured state of Aβ40 monomer has three more ordered segments at 14–18, 29–30, and 38–40. Interactions between these segments may stabilize the structured state, which likely plays an important role in Aβ aggregation. PMID:22277652

  4. Inhibition of odontogenic differentiation of human dental pulp cells by dental resin monomers

    OpenAIRE

    Kwon, Ji Hyun; Park, Hee Chul; Zhu, Tingting; Yang, Hyeong-Cheol

    2015-01-01

    Background Dental resin monomers that are leached from the resin matrix due to incomplete polymerization can affect the viability and various functions of oral tissues and cells. In this study, the effects of triethylene glycol dimethacrylate (TEGDMA) and 2-hydroxyethyl methacrylate (HEMA) on odontogenic differentiation of human dental pulp cells (HDPCs) were examined. To mimic clinical situations, dental pulp cells were treated with resin monomers for 24?h prior to the analysis of alkaline p...

  5. Organocatalytic conjugate-addition polymerization of linear and cyclic acrylic monomers by N-heterocyclic carbenes: Mechanisms of chain initiation, propagation, and termination

    KAUST Repository

    Zhang, Yuetao

    2013-11-27

    This contribution presents a full account of experimental and theoretical/computational investigations into the mechanisms of chain initiation, propagation, and termination of the recently discovered N-heterocyclic carbene (NHC)-mediated organocatalytic conjugate-addition polymerization of acrylic monomers. The current study specifically focuses on three commonly used NHCs of vastly different nucleophilicity, 1,3-di-tert-butylimidazolin-2-ylidene (ItBu), 1,3- dimesitylimidazolin-2-ylidene (IMes), and 1,3,4-triphenyl-4,5-dihydro-1H-1,2,4- triazol-5-ylidene (TPT), and two representative acrylic monomers, the linear methyl methacrylate (MMA) and its cyclic analog, biomass-derived renewable γ-methyl-α-methylene-γ-butyrolactone (MMBL). For MMA, there exhibits an exquisite selectivity of the NHC structure for the three types of reactions it promotes: enamine formation (single-monomer addition) by IMes, dimerization (tail-to-tail) by TPT, and polymerization by ItBu. For MMBL, all three NHCs promote no dimerization but polymerization, with the polymerization activity being highly sensitive to the NHC structure and the solvent polarity. Thus, ItBu is the most active catalyst of the series and converts quantitatively 1000-3000 equiv of MMBL in 1 min or 10 000 equiv in 5 min at room temperature to MMBL-based bioplastics with a narrow range of molecular weights of Mn = 70-85 kg/mol, regardless of the [MMBL]/[ItBu] ratio employed. The ItBu-catalyzed MMBL polymerization reaches an exceptionally high turnover frequency up to 122 s -1 and a high initiator efficiency value up to 1600%. Unique chain-termination mechanisms have been revealed, accounting for the production of relative high-molecular-weight linear polymers and the catalytic nature of this NHC-mediated conjugate-addition polymerization. Computational studies have provided mechanistic insights into reactivity and selectivity between two competing pathways for each NHC-monomer zwitterionic adduct, namely enamine

  6. Organocatalytic conjugate-addition polymerization of linear and cyclic acrylic monomers by N-heterocyclic carbenes: Mechanisms of chain initiation, propagation, and termination

    KAUST Repository

    Zhang, Yuetao; Schmitt, Meghan L.; Falivene, Laura; Caporaso, Lucia; Cavallo, Luigi; Chen, Eugene You Xian

    2013-01-01

    This contribution presents a full account of experimental and theoretical/computational investigations into the mechanisms of chain initiation, propagation, and termination of the recently discovered N-heterocyclic carbene (NHC)-mediated organocatalytic conjugate-addition polymerization of acrylic monomers. The current study specifically focuses on three commonly used NHCs of vastly different nucleophilicity, 1,3-di-tert-butylimidazolin-2-ylidene (ItBu), 1,3- dimesitylimidazolin-2-ylidene (IMes), and 1,3,4-triphenyl-4,5-dihydro-1H-1,2,4- triazol-5-ylidene (TPT), and two representative acrylic monomers, the linear methyl methacrylate (MMA) and its cyclic analog, biomass-derived renewable γ-methyl-α-methylene-γ-butyrolactone (MMBL). For MMA, there exhibits an exquisite selectivity of the NHC structure for the three types of reactions it promotes: enamine formation (single-monomer addition) by IMes, dimerization (tail-to-tail) by TPT, and polymerization by ItBu. For MMBL, all three NHCs promote no dimerization but polymerization, with the polymerization activity being highly sensitive to the NHC structure and the solvent polarity. Thus, ItBu is the most active catalyst of the series and converts quantitatively 1000-3000 equiv of MMBL in 1 min or 10 000 equiv in 5 min at room temperature to MMBL-based bioplastics with a narrow range of molecular weights of Mn = 70-85 kg/mol, regardless of the [MMBL]/[ItBu] ratio employed. The ItBu-catalyzed MMBL polymerization reaches an exceptionally high turnover frequency up to 122 s -1 and a high initiator efficiency value up to 1600%. Unique chain-termination mechanisms have been revealed, accounting for the production of relative high-molecular-weight linear polymers and the catalytic nature of this NHC-mediated conjugate-addition polymerization. Computational studies have provided mechanistic insights into reactivity and selectivity between two competing pathways for each NHC-monomer zwitterionic adduct, namely enamine

  7. Roasting conditions for preserving cocoa flavan-3-ol monomers and oligomers: interesting behaviour of Criollo clones.

    Science.gov (United States)

    De Taeye, Cédric; Bodart, Marie; Caullet, Gilles; Collin, Sonia

    2017-09-01

    Cocoa bean roasting is important for creating the typical chocolate aroma through Maillard reactions, but it is also a key step deleterious to the polyphenol content and profile. Compared with usual roasting at 150 °C, keeping the beans for 30 min at 120 °C or for 1 h at 90 °C proved much better for preventing strong degradation of native P1, P2 and P3 flavan-3-ols in cocoa (shown for Forastero, Trinitatio and Criollo cultivars). Surprisingly, Cuban, Mexican and Malagasy white-seeded beans behaved atypically when roasted for 30 min at 150 °C, releasing a pool of catechin. Enantiomeric chromatographic separation proved that this pool contained mainly (-)-catechin issued from (-)-epicatechin by epimerisation. As the (-)-epicatechin content remained relatively constant through Criollo bean roasting, flavan-3-ol monomers must have been regenerated from oligomers. This emergence of (-)-catechin in Criollo beans only, reported here for the first time, could be due to increased flavan-3-ol monomer stability in the absence of anthocyanidin-derived products. The degradation rate of flavan-3-ols through roasting is higher in cocoa beans containing anthocyani(di)ns. The liberation of a pool of (-)-catechin when submitted to roasting at 150 °C allows to distinguish white-seeded cultivars. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  8. Triptycene-based ladder monomers and polymers, methods of making each, and methods of use

    KAUST Repository

    Pinnau, Ingo

    2015-02-05

    Embodiments of the present disclosure provide for a triptycene-based A-B monomer, a method of making a triptycene-based A-B monomer, a triptycene-based ladder polymer, a method of making a triptycene-based ladder polymers, a method of using triptycene-based ladder polymers, a structure incorporating triptycene-based ladder polymers, a method of gas separation, and the like.

  9. Initial Reactivity of Linkages and Monomer Rings in Lignin Pyrolysis Revealed by ReaxFF Molecular Dynamics.

    Science.gov (United States)

    Zhang, Tingting; Li, Xiaoxia; Guo, Li

    2017-10-24

    The initial conversion pathways of linkages and their linked monomer units in lignin pyrolysis were investigated comprehensively by ReaxFF MD simulations facilitated by the unique VARxMD for reaction analysis. The simulated molecular model contains 15 920 atoms and was constructed on the basis of Adler's softwood lignin model. The simulations uncover the initial conversion ratio of various linkages and their linked aryl monomers. For linkages and their linked monomer aryl rings of α-O-4, β-O-4 and α-O-4 & β-5, the C α /C β ether bond cracking dominates the initial pathway accounting for at least up to 80% of their consumption. For the linkage of β-β & γ-O-α, both the C α -O ether bond cracking and its linked monomer aryl ring opening are equally important. Ring-opening reactions dominate the initial consumption of other 4-O-5, 5-5, β-1, β-2, and β-5 linkages and their linked monomers. The ether bond cracking of C α -O and C β -O occurs at low temperature, and the aryl ring-opening reactions take place at relatively high temperature. The important intermediates leading to the stable aryl ring opening are the phenoxy radicals, the bridged five-membered and three-membered rings and the bridged six-membered and three-membered rings. In addition, the reactivity of a linkage and its monomer aryl ring may be affected by other linkages. The ether bond cracking of α-O-4 and β-O-4 linkages can activate its neighboring linkage or monomer ring through the formed phenoxy radicals as intermediates. The important intermediates revealed in this article should be of help in deepening the understanding of the controlling mechanism for producing aromatic chemicals from lignin pyrolysis.

  10. Synthesis and ATRP of novel fluorinated aromatic monomer with pendant sulfonate group

    DEFF Research Database (Denmark)

    Dimitrov, Ivaylo; Jankova Atanasova, Katja; Hvilsted, Søren

    2013-01-01

    Novel, fluorinated monomer with pendant sulfonate group was synthesized utilizing a two-step derivatization of 2,3,4,5,6-pentafluorostyrene (FS). The first step was a nucleophilic substitution of the fluorine atom in para position by hydroxyl group followed by sulfopropylation. The monomer...... was polymerized under aqueous ATRP conditions to yield phenyl-fluorinated aromatic homopolymer bearing pendant sulfonates on each repeating unit. Furthermore, this polymer was used as macroinitiator for the ATRP of poly(ethylene glycol) methacrylate. The polymers were characterized by 1H NMR, SEC and FTIR...

  11. Synthesis of New Vinyl Monomers for Chemical Agent Sensing Applications

    National Research Council Canada - National Science Library

    Hogen-Esch, Thieo

    2001-01-01

    The synthesis of styrene momomer p-vinylbenzoylacetophenone (monomer i) has been carried by the acetylation of 2- chloroethylbenzene and base elimination of the resulting 4-acetyl-2-chloroethylbenzene to give 4-acetylstyrene...

  12. Iterative noise removal from temperature and density profiles in the TJ-II Thomson scattering

    International Nuclear Information System (INIS)

    Farias, G.; Dormido-Canto, S.; Vega, J.; Santos, M.; Pastor, I.; Fingerhuth, S.; Ascencio, J.

    2014-01-01

    TJ-II Thomson Scattering diagnostic provides temperature and density profiles of plasma. The CCD camera acquires images that are corrupted with some kind of noise called stray-light. This noise degrades both image contrast and measurement accuracy, which could produce unreliable profiles of the diagnostic. So far, several approaches have been applied in order to decrease the noise in the TJ-II Thomson scattering images. Since the presence of the noise is not global but located in some particular regions of the image, advanced processing techniques are needed. However such methods require of manual fine-tuning of parameters to reach a good performance. In this contribution, an iterative image processing approach is applied in order to reduce the stray light effects in the images of the TJ-II Thomson scattering diagnostic. The proposed solution describes how the noise can be iteratively reduced in the images when a key parameter is automatically adjusted during the iterative process

  13. Iterative noise removal from temperature and density profiles in the TJ-II Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Farias, G., E-mail: gonzalo.farias@ucv.cl [Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso (Chile); Dormido-Canto, S., E-mail: sebas@dia.uned.es [Departamento de Informática y Automática, UNED, 28040 Madrid (Spain); Vega, J., E-mail: jesus.vega@ciemat.es [Asociación EURATOM/CIEMAT para Fusión, Avd. Complutense 22, 28040 Madrid (Spain); Santos, M., E-mail: msantos@ucm.es [Departamento de Arquitectura de Computadores y Automática, Universidad Complutense de Madrid, 28040 Madrid (Spain); Pastor, I., E-mail: ignacio.pastor@ciemat.es [Asociación EURATOM/CIEMAT para Fusión, Avd. Complutense 22, 28040 Madrid (Spain); Fingerhuth, S., E-mail: sebastian.fingerhuth@ucv.cl [Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso (Chile); Ascencio, J., E-mail: j_ascencio21@hotmail.com [Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso (Chile)

    2014-05-15

    TJ-II Thomson Scattering diagnostic provides temperature and density profiles of plasma. The CCD camera acquires images that are corrupted with some kind of noise called stray-light. This noise degrades both image contrast and measurement accuracy, which could produce unreliable profiles of the diagnostic. So far, several approaches have been applied in order to decrease the noise in the TJ-II Thomson scattering images. Since the presence of the noise is not global but located in some particular regions of the image, advanced processing techniques are needed. However such methods require of manual fine-tuning of parameters to reach a good performance. In this contribution, an iterative image processing approach is applied in order to reduce the stray light effects in the images of the TJ-II Thomson scattering diagnostic. The proposed solution describes how the noise can be iteratively reduced in the images when a key parameter is automatically adjusted during the iterative process.

  14. Concomitant sensitization to glutaraldehyde and methacrylic monomers among dentists and their patients

    Directory of Open Access Journals (Sweden)

    Maya Grigorievna Lyapina

    2016-06-01

    Full Text Available Background: A multitude of methacrylic monomers is used in dentistry. Glutaraldehyde (G is used in dental practice and consumer products as a broad-spectrum antimicrobial agent. The purpose of our study is to evaluate the frequency and the risk of concomitant sensitization to some methacrylic monomers (methyl methacrylate (MMA, triethyleneglycol dimethacrylate (TEGDMA, ethyleneglycol dimethacrylate (EGDMA, 2,2-bis-[4-(2-hydroxy-3-methacrylo-xypropoxyphenyl]-propane (Bis-GMA, 2-hydroxy-ethyl methacrylate (2-HEMA and tetrahydrofurfuryl methacrylate (THFMA and glutaraldehyde in students of dentistry, students from the dental technician school, dental professionals and dental patients. Material and Methods: A total of 262 participants were included in the study: students of dentistry, students from the dental technician school, dental professionals, and dental patients as a control group. All were patch-tested with methacrylic monomers and glutaraldehyde. The results were subject to the statistical analysis (p < 0.05. Results: Among the group of dental students, the highest frequency of concomitant sensitization was to TEGDMA and G (15.5%. In the group of patients the highest frequency of concomitant sensitization was to EGDMA and G (16.4%. The frequency of concomitant sensitization among dental professionals was much lower, with the highest rate to TEGDMA and G (7.7%, too. We consider the students from the dental technician school, where the exposure to glutaraldehyde is less likely, to be the group at a lesser risk of concomitant sensitization. Conclusions: Dental students and dental patients could be outlined as groups at the risk of concomitant sensitization to glutaraldehyde and methacrylic monomers. For dental professionals, we assumed an increased risk for concomitant sensitization to TEGDMA and aldehydes that are commonly used in dentistry. We consider the students from the dental technician school to be the group at a lesser risk of

  15. High-Latitude Topside Ionospheric Vertical Electron Density Profile Changes in Response to Large Magnetic Storms

    Science.gov (United States)

    Benson, Robert F.; Fainberg, Joseph; Osherovich, Vladimir A.; Truhlik, Vladimir; Wang, Yongli; Bilitza, Dieter; Fung, Shing F.

    2016-01-01

    Large magnetic-storm-induced changes were detected in high-latitude topside vertical electron density profiles Ne(h) in a database of profiles and digital topside ionograms, from the International Satellites for Ionospheric Studies (ISIS) program, that enabled Ne(h) profiles to be obtained in nearly the same region of space before, during, and after a major magnetic storm (Dst -100nT). Storms where Ne(h) profiles were available in the high-latitude Northern Hemisphere had better coverage of solar wind parameters than storms with available Ne(h) profiles in the high-latitude Southern Hemisphere. Large Ne(h) changes were observed during all storms, with enhancements and depletions sometimes near a factor of 10 and 0.1, respectively, but with substantial differences in the responses in the two hemispheres. Large spatial andor temporal Ne(h) changes were often observed during Dst minimum and during the storm recovery phase. The storm-induced Ne(h) changes were the most pronounced and consistent in the Northern Hemisphere in that large enhancements were observed during winter nighttime and large depletions during winter and spring daytime. The limited available cases suggested that these Northern Hemisphere enhancements increased with increases of the time-shifted solar wind velocity v, magnetic field B, and with more negative values of the B components except for the highest common altitude (1100km) of the profiles. There was also some evidence suggesting that the Northern Hemisphere depletions were related to changes in the solar wind parameters. Southern Hemisphere storm-induced enhancements and depletions were typically considerably less with depletions observed during summer nighttime conditions and enhancements during summer daytime and fall nighttime conditions.

  16. Molecular Model for HNBR with Tunable Cross-Link Density.

    Science.gov (United States)

    Molinari, N; Khawaja, M; Sutton, A P; Mostofi, A A

    2016-12-15

    We introduce a chemically inspired, all-atom model of hydrogenated nitrile butadiene rubber (HNBR) and assess its performance by computing the mass density and glass-transition temperature as a function of cross-link density in the structure. Our HNBR structures are created by a procedure that mimics the real process used to produce HNBR, that is, saturation of the carbon-carbon double bonds in NBR, either by hydrogenation or by cross-linking. The atomic interactions are described by the all-atom "Optimized Potentials for Liquid Simulations" (OPLS-AA). In this paper, first, we assess the use of OPLS-AA in our models, especially using NBR bulk properties, and second, we evaluate the validity of the proposed model for HNBR by investigating mass density and glass transition as a function of the tunable cross-link density. Experimental densities are reproduced within 3% for both elastomers, and qualitatively correct trends in the glass-transition temperature as a function of monomer composition and cross-link density are obtained.

  17. Restricted primitive model for electrical double layers: modified HNC theory of density profiles and Monte Carlo study of differential capacitance

    International Nuclear Information System (INIS)

    Ballone, P.; Pastore, G.; Tosi, M.P.

    1986-02-01

    Interfacial properties of an ionic fluid next to a uniformly charged planar wall are studied in the restricted primitive model by both theoretical and Monte Carlo methods. The system is a 1:1 fluid of equisized charged hard spheres in a state appropriate to 1M aqueous electrolyte solutions. The interfacial density profiles of counterions and coions are evaluated by extending the hypernetted chain approximation (HNC) to include the leading bridge diagrams for the wall-ion correlations. The theoretical results compare well with those of grand canonical Monte Carlo computations of Torrie and Valleau over the whole range of surface charge density considered by these authors, thus resolving the earlier disagreement between statistical mechanical theories and simulation data at large charge densities. In view of the importance of the model as a testing ground for theories of the diffuse layer, the Monte Carlo calculations are tested by considering alternative choices for the basic simulation cell and are extended so as to allow an evaluation of the differential capacitance of the model interface by two independent methods. These involve numerical differentiation of the mean potential drop as a function of the surface charge density or alternatively an appropriate use of a fluctuation theory formula for the capacitance. The results of these two Monte Carlo approaches consistently indicate an initially smooth increase of the diffuse layer capacitance followed by structure at large charge densities, this behaviour being connected with layering of counterions as already revealed in the density profiles reported by Torrie and Valleau. (author)

  18. TEGDMA and UDMA monomers released from composite dental material polymerized with diode and halogen lamps.

    Science.gov (United States)

    Wacławczyk, Agnieszka; Postek-Stefańska, Lidia; Pietraszewska, Daria; Birkner, Ewa; Zalejska-Fiolka, Jolanta; Wysoczańska-Jankowicz, Iwona

    2018-03-20

    More than 35 substances released from composite fillings have been identified. Among these, basic monomers and the so-called co-monomers are most often reported. The substances released from polymer-based materials demonstrate allergenic, cytotoxic, genotoxic, mutagenic, embryotoxic, teratogenic, and estrogenic properties. The aim of this study was to measure the amounts of triethylene glycol dimethacrylate (TEGDMA) and urethane dimethacrylate (UDMA) monomers released from composite dental fillings to citrate-phosphate buffer with the pH of 4, 6, 8 after 24 h and 6 months from the polymerization. Ten samples for each polymerization method had been made from the composite material (Filtek Supreme XT, 3M ESPE, St. Paul, USA), which underwent polymerization using the following lamps: halogen lamp (Translux CL, Heraeus Kulzer, Hanau, Germany) (sample H) and diode lamp (Elipar Freelight 2, 3M ESPE), with soft start function (group DS) and without that function (group DWS). It has been demonstrated that the type of light-curing units has a significant impact on the amount of TEGDMA and UDMA released. The amount of UDMA and TEGDMA monomers released from composite fillings differed significantly depending on the source of polymerization applied, as well as the pH of the solution and sample storage time. Elution of the monomers from composite material polymerized using halogen lamp was significantly greater as compared to curing with diode lamps.

  19. Photoligation of self-assembled DNA constructs containing anthracene-functionalized 2'-amino-LNA monomers

    DEFF Research Database (Denmark)

    Pasternak, Karol; Pasternak, Anna; Gupta, Pankaj

    2011-01-01

    Efficient synthesis of a novel anthracene-functionalized 2'-amino-LNA phosphoramidite derivative is described together with its incorporation into oligodeoxynucleotides. Two DNA strands with the novel 2'-N-anthracenylmethyl-2'-amino-LNA monomers can be effectively cross-linked by photoligation...... at 366nm in various types of DNA constructs. Successful application of three differently functionalized 2'-amino-LNA monomers in self-assembled higher ordered structures for simultaneous cross-linking and monitoring of assembly formation is furthermore demonstrated....

  20. Determination of dislocation density by electron backscatter diffraction and X-ray line profile analysis in ferrous lath martensite

    International Nuclear Information System (INIS)

    Berecz, Tibor; Jenei, Péter; Csóré, András; Lábár, János; Gubicza, Jenő

    2016-01-01

    The microstructure and the dislocation density in as-quenched ferrous lath martensite were studied by different methods. The blocks, packets and variants formed due to martensitic transformation were identified and their sizes were determined by electron backscatter diffraction (EBSD). Concomitant transmission electron microscopy (TEM) investigation revealed that the laths contain subgrains with the size between 50 and 100 nm. A novel evaluation procedure of EBSD images was elaborated for the determination of the density and the space distribution of geometrically necessary dislocations from the misorientation distribution. The total dislocation density obtained by X-ray diffraction line profile analysis was in good agreement with the value determined by EBSD, indicating that the majority of dislocations formed due to martensitic transformation during quenching are geometrically necessary dislocations.

  1. Syringyl Methacrylate, a Hardwood Lignin-Based Monomer for High-Tg Polymeric Materials.

    Science.gov (United States)

    Holmberg, Angela L; Reno, Kaleigh H; Nguyen, Ngoc A; Wool, Richard P; Epps, Thomas H

    2016-05-17

    As viable precursors to a diverse array of macromolecules, biomass-derived compounds must impart wide-ranging and precisely controllable properties to polymers. Herein, we report the synthesis and subsequent reversible addition-fragmentation chain-transfer polymerization of a new monomer, syringyl methacrylate (SM, 2,6-dimethoxyphenyl methacrylate), that can facilitate widespread property manipulations in macromolecules. Homopolymers and heteropolymers synthesized from SM and related monomers have broadly tunable and highly controllable glass transition temperatures ranging from 114 to 205 °C and zero-shear viscosities ranging from ∼0.2 kPa·s to ∼17,000 kPa·s at 220 °C, with consistent thermal stabilities. The tailorability of these properties is facilitated by the controlled polymerization kinetics of SM and the fact that one vs two o -methoxy groups negligibly affect monomer reactivity. Moreover, syringol, the precursor to SM, is an abundant component of depolymerized hardwood (e.g., oak) and graminaceous (e.g., switchgrass) lignins, making SM a potentially sustainable and low-cost candidate for tailoring macromolecular properties.

  2. MGS Radio Science Electron Density Profiles: Interannual Variability and Implications for the Martian Neutral Atmosphere

    Science.gov (United States)

    Bougher, S. W.; Engel, S.; Hinson, D. P.; Murphy, J. R.

    2004-01-01

    Martian electron density profiles provided by the Mars Global Surveyor (MGS) Radio Science (RS) experiment over the 95-200 km altitude range indicate what the height of the electron peak and the longitudinal structure of the peak height are sensitive indicators of the physical state of the Mars lower and upper atmospheres. The present analysis is carried out on five sets of occultation profiles, all at high solar zenith angles (SZA). Variations spanning 2 Martian years are investigated near aphelion conditions at high northern latitudes (64.7 - 77.6 N) making use of four of these data sets. A mean ionospheric peak height of 133.5 - 135 km is obtained near SZA = 78 - 82 deg.; a corresponding mean peak density of 7.3 - 8.5 x l0(exp 4)/ qu cm is also measured during solar moderate conditions at Mars. Strong wave number 2 - 3 oscillations in peak heights are consistently observed as a function of longitude over the 2 Martian years. These observed ionospheric features are remarkably similar during aphelion conditions 1 Martian year apart. This year-to-year repeatability in the thermosphere-ionosphere structure is consistent with that observed in multiyear aphelion temperature data of the Mars lower atmosphere. Coupled Mars general circulation model (MGCM) and Mars thermospheric general circulation model (MTGCM) codes are run for Mars aphelion conditions, yielding mean and longitude variable ionospheric peak heights that reasonably match RS observations. A tidal decomposition of MTGCM thermospheric densities shows that observed ionospheric wave number 3 features are linked to a non-migrating tidal mode with semidiurnal period (sigma = 2) and zonal wave number 1 (s = -1) characteristics. The height of this photochemically determined ionospheric peak should be monitored regularly.

  3. Tidal Disruption of Milky Way Satellites with Shallow Dark Matter Density Profiles

    Directory of Open Access Journals (Sweden)

    Ewa L. Łokas

    2016-11-01

    Full Text Available Dwarf galaxies of the Local Group provide unique possibilities to test current theories of structure formation. Their number and properties have put the broadly accepted cold dark matter model into question, posing a few problems. These problems now seem close to resolution due to the improved treatment of baryonic processes in dwarf galaxy simulations which now predict cored rather than cuspy dark matter profiles in isolated dwarfs with important consequences for their subsequent environmental evolution. Using N-body simulations, we study the evolution of a disky dwarf galaxy with such a shallow dark matter profile on a typical orbit around the Milky Way. The dwarf survives the first pericenter passage but is disrupted after the second due to tidal forces from the host. We discuss the evolution of the dwarf’s properties in time prior to and at the time of disruption. We demonstrate that the dissolution occurs on a rather short timescale as the dwarf expands from a spheroid into a stream with non-zero mean radial velocity. We point out that the properties of the dwarf at the time of disruption may be difficult to distinguish from bound configurations, such as tidally induced bars, both in terms of surface density and line-of-sight kinematics.

  4. Joint refinement model for the spin resolved one-electron reduced density matrix of YTiO3 using magnetic structure factors and magnetic Compton profiles data.

    Science.gov (United States)

    Gueddida, Saber; Yan, Zeyin; Kibalin, Iurii; Voufack, Ariste Bolivard; Claiser, Nicolas; Souhassou, Mohamed; Lecomte, Claude; Gillon, Béatrice; Gillet, Jean-Michel

    2018-04-28

    In this paper, we propose a simple cluster model with limited basis sets to reproduce the unpaired electron distributions in a YTiO 3 ferromagnetic crystal. The spin-resolved one-electron-reduced density matrix is reconstructed simultaneously from theoretical magnetic structure factors and directional magnetic Compton profiles using our joint refinement algorithm. This algorithm is guided by the rescaling of basis functions and the adjustment of the spin population matrix. The resulting spin electron density in both position and momentum spaces from the joint refinement model is in agreement with theoretical and experimental results. Benefits brought from magnetic Compton profiles to the entire spin density matrix are illustrated. We studied the magnetic properties of the YTiO 3 crystal along the Ti-O 1 -Ti bonding. We found that the basis functions are mostly rescaled by means of magnetic Compton profiles, while the molecular occupation numbers are mainly modified by the magnetic structure factors.

  5. THE BOSS EMISSION-LINE LENS SURVEY. II. INVESTIGATING MASS-DENSITY PROFILE EVOLUTION IN THE SLACS+BELLS STRONG GRAVITATIONAL LENS SAMPLE

    Energy Technology Data Exchange (ETDEWEB)

    Bolton, Adam S.; Brownstein, Joel R.; Shu Yiping; Arneson, Ryan A. [Department of Physics and Astronomy, University of Utah, 115 South 1400 East, Salt Lake City, UT 84112 (United States); Kochanek, Christopher S. [Department of Astronomy and Center for Cosmology and Astroparticle Physics, Ohio State University, Columbus, OH 43210 (United States); Schlegel, David J. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Eisenstein, Daniel J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 20, Cambridge, MA 02138 (United States); Wake, David A. [Department of Astronomy, Yale University, New Haven, CT 06520 (United States); Connolly, Natalia [Department of Physics, Hamilton College, Clinton, NY 13323 (United States); Maraston, Claudia [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX (United Kingdom); Weaver, Benjamin A., E-mail: bolton@astro.utah.edu [Center for Cosmology and Particle Physics, New York University, New York, NY 10003 (United States)

    2012-09-20

    We present an analysis of the evolution of the central mass-density profile of massive elliptical galaxies from the SLACS and BELLS strong gravitational lens samples over the redshift interval z Almost-Equal-To 0.1-0.6, based on the combination of strong-lensing aperture mass and stellar velocity-dispersion constraints. We find a significant trend toward steeper mass profiles (parameterized by the power-law density model with {rho}{proportional_to}r {sup -{gamma}}) at later cosmic times, with magnitude d < {gamma} > /dz = -0.60 {+-} 0.15. We show that the combined lens-galaxy sample is consistent with a non-evolving distribution of stellar velocity dispersions. Considering possible additional dependence of <{gamma} > on lens-galaxy stellar mass, effective radius, and Sersic index, we find marginal evidence for shallower mass profiles at higher masses and larger sizes, but with a significance that is subdominant to the redshift dependence. Using the results of published Monte Carlo simulations of spectroscopic lens surveys, we verify that our mass-profile evolution result cannot be explained by lensing selection biases as a function of redshift. Interpreted as a true evolutionary signal, our result suggests that major dry mergers involving off-axis trajectories play a significant role in the evolution of the average mass-density structure of massive early-type galaxies over the past 6 Gyr. We also consider an alternative non-evolutionary hypothesis based on variations in the strong-lensing measurement aperture with redshift, which would imply the detection of an 'inflection zone' marking the transition between the baryon-dominated and dark-matter halo-dominated regions of the lens galaxies. Further observations of the combined SLACS+BELLS sample can constrain this picture more precisely, and enable a more detailed investigation of the multivariate dependences of galaxy mass structure across cosmic time.

  6. Profiles of plasma parameters and density of negative hydrogen ions by laser detachment measurements in RF-driven ion sources; Profile der Plasmaparameter und Dichte negativer Wasserstoffionen mittels Laserdetachmentmessungen in HF-angeregten Ionenquellen

    Energy Technology Data Exchange (ETDEWEB)

    Christ-Koch, Sina

    2007-12-20

    This work shows the application of the Laserdetachment method for spatially resolved measurements of negative Hydrogen/Deuterium ion density. It was applied on a high power low pressure RF-driven ion source. The Laser detachment method is based on the measurement of electron currents on a positively biased Langmuir probe before and during/after a laser pulse. The density ratio of negative ions to electrons can be derived from the ratio of currents to the probe. The absolute density of negative ions can be obtained when the electron density is measured with the standard Langmuir probe setup. Measurements with the Langmuir probe additionally yield information about the floating and plasma potential, the electron temperature and the density of positive ions. The Laser detachment setup had to be adapted to the special conditions of the RF-driven source. In particular the existence of RF fields (1 MHz), high source potential (-20 kV), magnetic fields ({proportional_to} 7 mT) and caesium inside the source had to be considered. The density of negative ions could be identified in the range of n(H{sup -})=1.10{sup 17} 1/m{sup 3}, which is in the same order of magnitude as the electron density. Only the application of the Laser detachment method with the Langmuir probe measurements will yield spatially resolved plasma parameters and H- density profiles. The influence of diverse external parameters, such as pressure, RF-power, magnetic fields on the plasma parameters and their profiles were studied and explained. Hence, the measurements lead to a detailed understanding of the processes inside the source. (orig.)

  7. Strong orientation dependence of surface mass density profiles of dark haloes at large scales

    Science.gov (United States)

    Osato, Ken; Nishimichi, Takahiro; Oguri, Masamune; Takada, Masahiro; Okumura, Teppei

    2018-06-01

    We study the dependence of surface mass density profiles, which can be directly measured by weak gravitational lensing, on the orientation of haloes with respect to the line-of-sight direction, using a suite of N-body simulations. We find that, when major axes of haloes are aligned with the line-of-sight direction, surface mass density profiles have higher amplitudes than those averaged over all halo orientations, over all scales from 0.1 to 100 Mpc h-1 we studied. While the orientation dependence at small scales is ascribed to the halo triaxiality, our results indicate even stronger orientation dependence in the so-called two-halo regime, up to 100 Mpc h-1. The orientation dependence for the two-halo term is well approximated by a multiplicative shift of the amplitude and therefore a shift in the halo bias parameter value. The halo bias from the two-halo term can be overestimated or underestimated by up to {˜ } 30 per cent depending on the viewing angle, which translates into the bias in estimated halo masses by up to a factor of 2 from halo bias measurements. The orientation dependence at large scales originates from the anisotropic halo-matter correlation function, which has an elliptical shape with the axis ratio of ˜0.55 up to 100 Mpc h-1. We discuss potential impacts of halo orientation bias on other observables such as optically selected cluster samples and a clustering analysis of large-scale structure tracers such as quasars.

  8. RELATIONSHIPS BETWEEN ANATOMICAL FEATURES AND INTRA-RING WOOD DENSITY PROFILES IN Gmelina arborea APPLYING X-RAY DENSITOMETRY

    Directory of Open Access Journals (Sweden)

    Mario Tomazelo-Filho

    2007-12-01

    Full Text Available Four annual tree-rings (2 of juvenile wood and 2 of mature wood were sampled from fast-growth plantations ofGmelina arborea in two climatic conditions (dry and wet tropical in Costa Rica. Each annual tree-ring was divided in equal parts ina radial direction. For each part, X-ray density as well as vessel percentage, length and width fiber, cell wall thickness and lumendiameter were measured. Wood density and profile patterns of cell dimension demonstrated inconsistency between juvenile andmature wood and climatic conditions. The Pearson correlation matrix showed that intra-ring wood density was positively correlatedwith the cell wall thickness and negatively correlated with vessel percentage, fiber length, lumen diameter and width. The forwardstepwise regressions determined that: (i intra-ring wood density variation could be predicted from 76 to 96% for anatomicalvariation; (ii cell wall thickness was the most important anatomical feature to produce intra-ring wood density variation and (iii thevessel percentage, fiber length, lumen diameter and width were the second most statically significant characteristics to intra-ring wooddensity, however, with low participation of the determination coefficient of stepwise regressions.

  9. A DFT based analysis of adsorption of Hg2+ ion on chitosan monomer and its citralidene and salicylidene derivatives: Prior to the removal of Hg toxicity.

    Science.gov (United States)

    Hassan, Basila; Rajan, Vijisha K; Mujeeb, V M Abdul; K, Muraleedharan

    2017-06-01

    A Density functional theory based study of adsorption of the toxic metal Hg (II) ion by chitosan monomer and two of its derivatives; citralidene and salicylidene chitosan, has been performed. The effect of structural features on the stability of studied complexes has been analyzed by using Gaussian03 software package. All the possible conformations of these adsorbents were studied using the global minimum geometries. All the adsorbing sites were studied by placing the metal ion on the centroid of the atoms and the stable conformer of the adsorbent-metal ion complex was identified. Interaction between Hg (II) and the adsorbents is found to be electrostatic. Metal ion binding with nitrogen atom is stronger than that with oxygen atoms in all the cases as the charge density of nitrogen is enhanced on Schiff base formation. The advantage of derivatives over chitosan monomer is their stability in acidic media. ΔE value of the complexes are in the order SC-Hg (II)>chitosan-Hg (II)>CC-Hg (II) which indicates that the stability of complexes increases with increase in energy gap. The study reveals that aromatic Schiff base derivatives of chitosan is better for Hg(II) intake than aliphatic derivatives. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Effect of pH and Monomer Dosing Rate in the Anionic Polymerization of Ethyl Cyanoacrylate in Semicontinuous Operation

    Directory of Open Access Journals (Sweden)

    Hened Saade

    2015-01-01

    Full Text Available Nanoparticles of poly(ethyl cyanoacrylate with more than 10% solids content were prepared by semicontinuous heterophase polymerization at monomer-starved conditions varying the initial pH in the interval of 1–1.75 and at two monomer dosing rates. Measurements by scanning-transmission electron microscopy allowed us to identify an inverse dependence of particle size on pH. Furthermore, all the polymerizations conducted at the slower monomer dosing rate rendered two particle populations, with the larger one formed from the aggregation of a fraction of the smaller particles. It was believed that the so slow addition of the monomer caused the formation of very small but instable particles, thereby a fraction of which aggregated to reduce the total interface particles-aqueous phase, increasing the latex stability. An increase in the monomer dosing rate led to larger and more stable particles in such way that only one population of nanoparticles with around 40 nm in average diameter was obtained.

  11. Fluorescent oligonucleotides containing a novel perylene 2′-amino-α-L-LNA monomer: Synthesis and analytical potential

    DEFF Research Database (Denmark)

    Astakhova, Irina; Kumar, Santhosh T.; Wengel, Jesper

    2011-01-01

    efficiency of the resulting perylene-2'-amino-alpha-L-LNA monomer (T*) into synthetic oligonucleotides was significantly improved by replacement of the typically used 1H-tetrazole activator with pyridine hydrochloride. Generally, oligonucleotides containing monomer T* showed high binding affinity towards...... incorporations of monomers T* was quenched (quantum yield Phi(F) = 0.21) relative to duplexes of this probe with complementary DNA and RNA (Phi(F) = 0.42 and 0.35, respectively). On the contrary, a strong fluorescence quenching upon target binding was demonstrated by two short oligonucleotides of analogues...... sequences containing monomers T* at 5'- and 3'-terminal positions. We explain the hybridization-induced light-up effect observed for double-labeled probe by a reduction of fluorescence quenching due to precise positioning of the fluorophores within the double-stranded complexes. Furthermore, we propose...

  12. Asymmetric Velocity Distributions from Halo Density Profiles in the Eddington Approach

    International Nuclear Information System (INIS)

    Vergados, J. D.

    2015-01-01

    We show how to obtain the energy distribution f(E) in our vicinity starting from WIMP density profiles in a self-consistent way by employing the Eddington approach and adding reasonable angular momentum dependent terms in the expression of the energy. We then show how we can obtain the velocity dispersions and the asymmetry parameter β in terms of the parameters describing the angular momentum dependence. From this expression, for f(E), we proceed to construct an axially symmetric WIMP a velocity distribution, which, for a gravitationally bound system, automatically has a velocity upper bound and is characterized by the same asymmetriy β. This approach is tested and clarified by constructing analytic expressions in a simple model, with adequate structure. We then show how such velocity distributions can be used in determining the event rates, including modulation, in both the standard and the directional WIMP searches.

  13. Sub-millisecond electron density profile measurement at the JET tokamak with the fast lithium beam emission spectroscopy system

    Science.gov (United States)

    Réfy, D. I.; Brix, M.; Gomes, R.; Tál, B.; Zoletnik, S.; Dunai, D.; Kocsis, G.; Kálvin, S.; Szabolics, T.; JET Contributors

    2018-04-01

    Diagnostic alkali atom (e.g., lithium) beams are routinely used to diagnose magnetically confined plasmas, namely, to measure the plasma electron density profile in the edge and the scrape off layer region. A light splitting optics system was installed into the observation system of the lithium beam emission spectroscopy diagnostic at the Joint European Torus (JET) tokamak, which allows simultaneous measurement of the beam light emission with a spectrometer and a fast avalanche photodiode (APD) camera. The spectrometer measurement allows density profile reconstruction with ˜10 ms time resolution, absolute position calculation from the Doppler shift, spectral background subtraction as well as relative intensity calibration of the channels for each discharge. The APD system is capable of measuring light intensities on the microsecond time scale. However ˜100 μs integration is needed to have an acceptable signal to noise ratio due to moderate light levels. Fast modulation of the beam up to 30 kHz is implemented which allows background subtraction on the 100 μs time scale. The measurement covers the 0.9 background subtraction, the relative calibration, and the comprehensive error calculation, runs a Bayesian density reconstruction code, and loads results to the JET database. The paper demonstrates the capability of the APD system by analyzing fast phenomena like pellet injection and edge localized modes.

  14. Using monomer vibrational wavefunctions to compute numerically exact (12D) rovibrational levels of water dimer

    Science.gov (United States)

    Wang, Xiao-Gang; Carrington, Tucker

    2018-02-01

    We compute numerically exact rovibrational levels of water dimer, with 12 vibrational coordinates, on the accurate CCpol-8sf ab initio flexible monomer potential energy surface [C. Leforestier et al., J. Chem. Phys. 137, 014305 (2012)]. It does not have a sum-of-products or multimode form and therefore quadrature in some form must be used. To do the calculation, it is necessary to use an efficient basis set and to develop computational tools, for evaluating the matrix-vector products required to calculate the spectrum, that obviate the need to store the potential on a 12D quadrature grid. The basis functions we use are products of monomer vibrational wavefunctions and standard rigid-monomer basis functions (which involve products of three Wigner functions). Potential matrix-vector products are evaluated using the F matrix idea previously used to compute rovibrational levels of 5-atom and 6-atom molecules. When the coupling between inter- and intra-monomer coordinates is weak, this crude adiabatic type basis is efficient (only a few monomer vibrational wavefunctions are necessary), although the calculation of matrix elements is straightforward. It is much easier to use than an adiabatic basis. The product structure of the basis is compatible with the product structure of the kinetic energy operator and this facilitates computation of matrix-vector products. Compared with the results obtained using a [6 + 6]D adiabatic approach, we find good agreement for the inter-molecular levels and larger differences for the intra-molecular water bend levels.

  15. High triglycerides and low high-density lipoprotein cholesterol lipid profile in rheumatoid arthritis: A potential link among inflammation, oxidative status, and dysfunctional high-density lipoprotein.

    Science.gov (United States)

    Rodríguez-Carrio, Javier; Alperi-López, Mercedes; López, Patricia; López-Mejías, Raquel; Alonso-Castro, Sara; Abal, Francisco; Ballina-García, Francisco J; González-Gay, Miguel Á; Suárez, Ana

    The interactions between inflammation and lipid profile in rheumatoid arthritis (RA) are poorly understood. The lipid profile study in RA has been biased toward lipoprotein levels, whereas those of triglycerides (TGs) and lipoprotein functionality have been underestimated. Since recent findings suggest a role for TG and TG-rich lipoproteins (TRL) on inflammation, we aimed to evaluate a combined lipid profile characterized by high TG and low high-density lipoprotein cholesterol levels (TG high HDL low ) in RA. Lipid profiles were analyzed in 113 RA patients, 113 healthy controls, and 27 dyslipemic subjects. Levels of inflammatory mediators, paraoxonase-1 (PON1) activity, and total antioxidant capacity were quantified in serum. PON1-rs662 status was evaluated by real-time polymerase chain reaction. The TG high HDL low profile was detected in 29/113 RA patients. Although no differences in prevalence compared with healthy controls or dyslipemic subjects were observed, this profile was associated with increased tumor necrosis factor α (P = .004), monocyte chemotactic protein (P = .004), interferon-gamma-inducible protein-10 (P = .018), and leptin (P < .001) serum levels in RA, where decreased PON1 activity and total antioxidant capacity were found. TG high HDL low prevalence was lower among anti-TNFα-treated patients (P = .004). When RA patients were stratified by PON1-rs662 status, these associations remained in the low-activity genotype (QQ). Finally, a poor clinical response on TNFα blockade was related to an increasing prevalence of the TG high HDL low profile over treatment (P = .021) and higher TRL levels at baseline (P = .042). The TG high HDL low profile is associated with systemic inflammation, decreased PON1 activity, and poor clinical outcome on TNFα blockade in RA, suggesting a role of TRL and HDL dysfunction as the missing link between inflammation and lipid profile. Copyright © 2017 National Lipid Association. Published by Elsevier Inc

  16. Effect of reactive monomer on PS-b-P2VP film with UV irradiation

    Science.gov (United States)

    Kim, H. J.; Shin, D. M.

    2012-03-01

    Poly(styrene-b-2-vinyl pyridine) (PS-b-P2VP) lamellar film which is hydrophobic block hydrophilic polyelectrolyte block polymer of 52 kg/mol -b- 57 kg/mol and PS-b-P2VP film with reactive monomer (RM257) were prepared for photonic gel films. The lamellar stacks, which is alternating layer of hydrophilic and hydrophobic part of PS-b-P2VP. We reported about the influence of reactive monomer on those photonic gel films. Added reactive monomer photonic gel film had higher absorbance than pure photonic gel films. And band gaps of the lamellar films shifted by the time of UV light irradiation. That Photonic gel films were measured with the UV spectrophotometer. As a result the photonic gel film with reactive monomer had more clear color. The lamellar films were swollen by DI water, Ethyl alcohol (aq) and calcium carbonate solution. Since the domain spacing of dried photonic gel films were not showing any color in visible wavelength. The band gap of the lamellar films were drastically shifted to longer wavelength swollen by calcium carbonate solution (absorbance peak 565nm-->617nm). And the lamellar films were shifted to shorter wave length swollen by ethanol (absorbance peak 565nm-->497nm). So each Photonic gel film showed different color.

  17. Inverse opal pH sensors with various protic monomers copolymerized with polyhydroxyethylmethacrylate hydrogel

    International Nuclear Information System (INIS)

    Shin, Jinsub; Han, Sung Gu; Lee, Wonmok

    2012-01-01

    Highlights: ► We polymerized four different inverse opal pH sensors by using vinyl monomers containing acidic or basic substituents. ► Stepwise swelling response from polyprotic acid sensor was investigated. ► Opposite color changing responses were obtained for acidic and basic sensors. ► Composite pH sensor with wide pH sensing range was fabricated by mixing different monomers. ► Both acid and base sensors show the response time as fast as ∼10 s. - Abstract: pH sensitive inverse opal sensors were synthesized using various vinyl monomers containing acidic or basic substituents. Acrylic acid (AA), vinylphosphonic acid (VPA), vinylimidazole (VI), and dimethylaminoethylmethacrylic acid (DMAEMA) were respectively copolymerized with hydroxyethylmethacrylate (HEMA), the building block monomer of the hydrogel via UV-initiated photopolymerization. Opal templating and subsequent template removal enabled the fabrication of four inverse opal (IO) hydrogel colorimetric sensors, which responded to pH in different fashions. pH-dependent swelling of the IO hydrogel induced the red-shift of the diffracted color. The sensors containing AA or VPA, the proton donating monomers showed the color shifts from green to red with pH increase due to the increased concentration of carboxylate anions bound to the hydrogel. Diprotic VPA sensor exhibited two-step increases of diffracted wavelengths at its pK a1 and pK a2 respectively. The sensors containing proton acceptors, VI and DMAEMA showed the pH-dependent color changes in an opposite way to the AA sensor and the VPA sensor since their ionizations take place by lowering pH due to the protonation at the amino groups. The shapes of pH response curves of VI and DMAEMA sensors were similar but pK b s were different from each other. Optical diffraction responses of four sensors were compared with the calculated concentration ratios of the ionized species to the total monomer with pH variation, and a deswelling effect in the

  18. Polymeric reaction of polymer-monomer system for pressure sensitive adhesives by low energy electron beam

    International Nuclear Information System (INIS)

    Takiguchi, R.; Uryu, T.

    1985-01-01

    Application of low-energy electron beam to non-solvent type pressure sensitive adhesives is investigated. The adhesive properties such as peel strength and holding time (dead-load strength) were closely related to the reaction of acrylate polymer-monomer systems. The reaction behavior is elucidated by combining the measurement of gel fraction, infrared spectrum of gel, and the molecular weight distribution detected by gel permeation chromatography. It was important for the production of pressure sensitive adhesives by electron beam that the adhesive with high peel strength and long holding time is composed of a proper combination of three factors, that is, about 35% gel fraction, 25% monomer units in gel, and 15% graft efficiency by irradiating the polymer-monomer system containing low molecular weight poly (butyl acrylate). (author)

  19. Absolute density measurements in the middle atmosphere

    Directory of Open Access Journals (Sweden)

    M. Rapp

    2001-05-01

    Full Text Available In the last ten years a total of 25 sounding rockets employing ionization gauges have been launched at high latitudes ( ~ 70° N to measure total atmospheric density and its small scale fluctuations in an altitude range between 70 and 110 km. While the determination of small scale fluctuations is unambiguous, the total density analysis has been complicated in the past by aerodynamical disturbances leading to densities inside the sensor which are enhanced compared to atmospheric values. Here, we present the results of both Monte Carlo simulations and wind tunnel measurements to quantify this aerodynamical effect. The comparison of the resulting ‘ram-factor’ profiles with empirically determined density ratios of ionization gauge measurements and falling sphere measurements provides excellent agreement. This demonstrates both the need, but also the possibility, to correct aerodynamical influences on measurements from sounding rockets. We have determined a total of 20 density profiles of the mesosphere-lower-thermosphere (MLT region. Grouping these profiles according to season, a listing of mean density profiles is included in the paper. A comparison with density profiles taken from the reference atmospheres CIRA86 and MSIS90 results in differences of up to 40%. This reflects that current reference atmospheres are a significant potential error source for the determination of mixing ratios of, for example, trace gas constituents in the MLT region.Key words. Middle atmosphere (composition and chemistry; pressure, density, and temperature; instruments and techniques

  20. Absolute density measurements in the middle atmosphere

    Directory of Open Access Journals (Sweden)

    M. Rapp

    Full Text Available In the last ten years a total of 25 sounding rockets employing ionization gauges have been launched at high latitudes ( ~ 70° N to measure total atmospheric density and its small scale fluctuations in an altitude range between 70 and 110 km. While the determination of small scale fluctuations is unambiguous, the total density analysis has been complicated in the past by aerodynamical disturbances leading to densities inside the sensor which are enhanced compared to atmospheric values. Here, we present the results of both Monte Carlo simulations and wind tunnel measurements to quantify this aerodynamical effect. The comparison of the resulting ‘ram-factor’ profiles with empirically determined density ratios of ionization gauge measurements and falling sphere measurements provides excellent agreement. This demonstrates both the need, but also the possibility, to correct aerodynamical influences on measurements from sounding rockets. We have determined a total of 20 density profiles of the mesosphere-lower-thermosphere (MLT region. Grouping these profiles according to season, a listing of mean density profiles is included in the paper. A comparison with density profiles taken from the reference atmospheres CIRA86 and MSIS90 results in differences of up to 40%. This reflects that current reference atmospheres are a significant potential error source for the determination of mixing ratios of, for example, trace gas constituents in the MLT region.

    Key words. Middle atmosphere (composition and chemistry; pressure, density, and temperature; instruments and techniques

  1. Bioaccumulation study of acrylate monomers in algae (Chlorella Kessleri) by PY-GC and PY-GC/MS

    International Nuclear Information System (INIS)

    Halas, L.; Orinak, A.; Adamova, M.; Ladomersky, J.

    2004-01-01

    Acrylate monomers methylmethacrylate (MMA) and cyclohexylmethacrylate (CHMA) bioaccumulation has been determined in aquatic organism, algae (Chlorella kessleri). Algae were collected in amount of 0.4 mg and directly injected to the paralytic cell. In algae bodies accumulated monomers were analysed by pyrolysis gas chromatography (Py-GC) and pyrolysis gas chromatography coupled with mass spectrometry (Py-GC/MS). Traces of the accumulated monomers in algae body can be determined after 1-, 2 -, 3-weeks of incubation. Maximum content of MMA was determined after 3-week of experiment, contrariwise in the case of CHMA after 2-week exposition. Relationship with pyrolysis temperature has also been studied. (authors)

  2. Effect of radiation combined with Chinese medicinal monomers on Me180 cells

    International Nuclear Information System (INIS)

    Geng Chuanying; Xu Bo; Li Hongyan; Chen Zhihua; Xia Qisheng; Xu Mei; Liu Xuan; Xiang Qing; Liu Yufeng

    2009-01-01

    Objective: To observe the effect of radiation treatment combined with Chinese medicinal monomers on the proliferation function, telomerase activity, expressions of apoptosis- and proliferation-related genes of Me180 cells. Methods: Me180 cells were cultured in the medium with oleanolic acid, curcumin and allicin. The survival rates of cells were detected by the methods of MTT, the telomerase activity by the method of telomeric repeat amplification protocol (TRAP) and the apoptosis -and proliferation-related genes by the method of reverse transeriptase-PCR. Me180 cells were cultured in the medium with Chinese medicinal monomers, and exposed to X-ray irradiation and the survival rates were detected. Results: The results of MTY showed that survival rates of tumor cells exposed to X rays in combination with oleanolic acid, curcumin and allicin were decreased significantly(t=2.81, 4.16, and 3.42, P<0.05). Chinese medicinal monomers inhibited the telomerase activity of MelS0 cells and the inhibiting function changed with time. At 16 h, the telomerase activities of MelS0 cells administered with oleanolic acid and allicin were reduced markedly (t=5.11 and 5.29, P<0.05). After 48 h, the telomerase activities returned to the normal level. The gene expressions of p21 and p16 in Me180 cells treated with oleanolic acid were 2.43 and 2.78 times higher than the control, respectively, while those of cyclin D1 and CDK4 were 56% and 41% of the control, respectively. Conclusions: Chinese medicinal monomers could effectively kill tumor cells, inhibit the telomerase activity and the expression of proliferation-related genes, and enhance the radiosensitivity of tumor cells. (authors)

  3. Sulfonated copolyimide membranes derived from a novel diamine monomer with pendant benzimidazole groups for fuel cells

    DEFF Research Database (Denmark)

    Li, Wei; Guo, Xiaoxia; Aili, David

    2015-01-01

    . A series of sulfonated copolyimides (SPI) are prepared via random copolymerizatio of 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA) with a new diamine monomer with pendant benzimidazole groups, 2,2'-bis(4-(1H-benzo[d]imidazol-2-yl)phenoxy)benzidine (BIPOB), and a sulfonated diamine monomer 4,4'-bis...

  4. Low temperature irradiation of vitrifiable mixtures of unsaturated monomers

    International Nuclear Information System (INIS)

    Kaetsu, I.; Ito, A.; Hayashi, K.

    1975-01-01

    A specific mixture containing at least one polymerizable unsaturated monomer which is not vitrifiable by itself can advantageously be polymerized by irradiating the mixture at a temperature not higher than 100 0 C above glass transition temperature of the mixture with an ionizing radiation and/or a light. 12 claims, 6 drawings, figures

  5. Regulation of the PI3K pathway through a p85a monomer-homodimer equilibrium

    KAUST Repository

    Aljedani, Safia Salim Eid

    2017-01-08

    The phosphatidylinositol-3-kinase a (PI3Ka) is heterodimeric enzyme that is composed of p85a regulatory subunit and a p110a catalytic subunit. PI3Ka plays a key role in cell survival, growth and differentation. Owing to its role as a key regulator, the PI3Ka pathway is the most frequently mutated pathway in human cancers, and is targeted by many viruses to insure their survival and successful reproduction. Previous studies have shown that the equilibrium of p85 monomers and dimers regulates the PI3K pathway, suggesting that interrupting this equilibrium could lead to disease development. Moreover, studies suggest that the p85a monomers and dimers have opposing effects on PI3Ka signaling as only the p85a dimers bind to the PTEN phosphatase, whereas p85a monomers bind to the catalytic p110 subunit. However, the mechanism for dimerisation is controversial, and it is unknown why PTEN or p110a bind only dimer or monomer. Therefore, we combine molecular biology, biophsical, computational and structural methods to investigate the suprosingly complex p85 dimerisation mechanism and its control by ligands. Results may inspire novel theraputic approaches.

  6. Spatial profiles of electron and metastable atom densities in positive polarity fast ionization waves sustained in helium

    International Nuclear Information System (INIS)

    Weatherford, Brandon R.; Barnat, E. V.; Xiong, Zhongmin; Kushner, Mark J.

    2014-01-01

    Fast ionization waves (FIWs), often generated with high voltage pulses over nanosecond timescales, are able to produce large volumes of ions and excited states at moderate pressures. The mechanisms of FIW propagation were experimentally and computationally investigated to provide insights into the manner in which these large volumes are excited. The two-dimensional structure of electron and metastable densities produced by short-pulse FIWs sustained in helium were measured using laser-induced fluorescence and laser collision-induced fluorescence diagnostics for times of 100–120 ns after the pulse, as the pressure was varied from 1 to 20 Torr. A trend of center-peaked to volume-filling to wall-peaked electron density profiles was observed as the pressure was increased. Instantaneous FIW velocities, obtained from plasma-induced emission, ranged from 0.1 to 3 × 10 9  cm s −1 , depending on distance from the high voltage electrode and pressure. Predictions from two-dimensional modeling of the propagation of a single FIW correlated well with the experimental trends in electron density profiles and wave velocity. Results from the model show that the maximum ionization rate occurs in the wavefront, and the discharge continues to propagate forward after the removal of high voltage from the powered electrode due to the potential energy stored in the space charge. As the pressure is varied, the radial distribution of the ionization rate is shaped by changes in the electron mean free path, and subsequent localized electric field enhancement at the walls or on the centerline of the discharge.

  7. Scaling laws for TEXT plasma profiles

    International Nuclear Information System (INIS)

    McCool, S.C.; Bravenec, R.V.; Chen, J.Y.; Foster, M.S.; Li, W.L.; Ouroura, A.; Phillips, P.E.; Richards, B.; Wenzel, K.W.; Zhang, Z.M.

    1994-01-01

    Regression analysis has been performed on a number of measured profiles including temperature and density vs. nominal macroscopic operating parameters for TEXT tokamak (pre-upgrade) ohmic plasmas. The resulting simple empirical model has enabled the authors to quickly approximate profiles of electron temperature and density, ion temperature, and soft x-ray brightness, as well as the scalar quantities: total radiated power, q=1 radius, sawtooth period and amplitude, and energy confinement time as a power law of toroidal field, plasma current, chord average density, and fueling gas atomic weight. The model profiles are only applicable to the plasma interior, i.e. within the limiter radius. In most cases the predicted model profiles are within the experimental error bars of measured profiles and are more accurate at predicting profile variation for small operating parameter changes than the measured profiles

  8. In depth fusion flame spreading with a deuterium—tritium plane fuel density profile for plasma block ignition

    International Nuclear Information System (INIS)

    Malekynia, B.; Razavipour, S. S.

    2012-01-01

    Solid-state fuel ignition was given by Chu and Bobin according to the hydrodynamic theory at x = 0 qualitatively. A high threshold energy flux density, i.e., E* = 4.3 × 10 12 J/m 2 , has been reached. Recently, fast ignition by employing clean petawatt—picosecond laser pulses was performed. The anomalous phenomena were observed to be based on suppression of prepulses. The accelerated plasma block was used to ignite deuterium—tritium fuel at solid-state density. The detailed analysis of the thermonuclear wave propagation was investigated. Also the fusion conditions at x ≠ 0 layers were clarified by exactly solving hydrodynamic equations for plasma block ignition. In this paper, the applied physical mechanisms are determined for nonlinear force laser driven plasma blocks, thermonuclear reaction, heat transfer, electron—ion equilibration, stopping power of alpha particles, bremsstrahlung, expansion, density dependence, and fluid dynamics. New ignition conditions may be obtained by using temperature equations, including the density profile that is obtained by the continuity equation and expansion velocity. The density is only a function of x and independent of time. The ignition energy flux density, E* t , for the x ≠ 0 layers is 1.95 × 10 12 J/m 2 . Thus threshold ignition energy in comparison with that at x = 0 layers would be reduced to less than 50 percent. (physics of gases, plasmas, and electric discharges)

  9. Recent measurements of electron density profiles of plasmas in PLADIS I, a plasma disruption simulator

    International Nuclear Information System (INIS)

    Bradley, J. III; Sharp, G.; Gahl, J.M. Kuznetsov, V.; Rockett, P.; Hunter, J.

    1995-01-01

    Tokamak disruption simulation experiments are being conducted at the University of New Mexico (UNM) using the PLADIS I plasma gun system. PLADIS I is a high power, high energy coaxial plasma gun configured to produce an intense plasma beam. First wall candidate materials are placed in the beam path to determine their response under disruption relevant energy densities. An optically thick vapor shield plasma has been observed to form above the target surface in PLADIS I. Various diagnostics have been used to determine the characteristics of the incident plasma and the vapor shielding plasma. The cross sectional area of the incident plasma beam is a critical characteristic, as it is used in the calculation of the incident plasma energy density. Recently, a HeNe interferometer in the Mach-Zehnder configuration has been constructed and used to probe the electron density of the incident plasma beam and vapor shield plasma. The object beam of the interferometer is scanned across the plasma beam on successive shots, yielding line integrals of beam density on different chords through the plasma. Data from the interferometer is used to determine the electron density profile of the incident plasma beam as a function of beam radius. This data is then used to calculate the effective beam area. Estimates. of beam area, obtained from other diagnostics such as damage targets, calorimeter arrays and off-axis measurements of surface pressure, will be compared with data from the interferometer to obtain a better estimate of the beam cross sectional area

  10. Fatty acid profile in patients with phenylketonuria and its relationship with bone mineral density.

    Science.gov (United States)

    Lage, Sergio; Bueno, María; Andrade, Fernando; Prieto, José Angel; Delgado, Carmen; Legarda, María; Sanjurjo, Pablo; Aldámiz-Echevarría, Luis Jose

    2010-12-01

    Patients with phenylketonuria (PKU) undergo a restrictive vegan-like diet, with almost total absence of n-3 fatty acids, which have been proposed as potential contributors to bone formation in the healthy population. The PKU diet might lead these patients to bone mass loss and, consequently, to the development of osteopenia/osteoporosis. Therefore, we proposed to analyze their plasma fatty acid profile status and its relationship with bone health. We recruited 47 PKU patients for this cross-sectional study and divided the cohort into three age groups (6-10 years, 11-18 years, 19-42 years). We measured their plasma fatty acid profile and bone mineral density (BMD) (both at the femoral neck and the lumbar spine). Seventy-seven healthy controls also participated as reference values of plasma fatty acids. Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) and total n-3 fatty acids were significantly diminished in PKU patients compared with healthy controls. DHA, EPA, and total n-3 fatty acids were also positively associated with bone mineral density (r = 0.83, p = 0.010; r = 0.57, p = 0.006; r = 0.73, p = 0.040, respectively). There was no association between phenylalanine (Phe), Index of Dietary Control (IDC), calcium, 25-hydroxivitamin D concentrations, daily calcium intake, and BMD. Our results suggest a possible influence of essential fatty acids over BMD in PKU patients. The lack of essential n-3 fatty acids intake in the PKU diet might affect bone mineralization. Further clinical trials are needed to confirm the effect of the n-3 essential fatty acids on bone accrual in a cohort of PKU patients.

  11. Vinyl Monomers Double as UV Stabilizers: 179th ACS Meeting Houston.

    Science.gov (United States)

    Chemical and Engineering News, 1980

    1980-01-01

    Synthesis and polymerization of vinyl monomers that double as stabilizers against degradation of plastics by ultraviolet light has been accomplished. Potential applications include protection of photovoltaic cells in solar power plants. (Author/RE)

  12. Effect of monomer concentration on the kinetics of emulsifier-free emulsion polymerization of Vinyl Acetate and Methyl Acrylate

    International Nuclear Information System (INIS)

    Mohammad Beigi, H. R.

    2001-01-01

    The effect of monomer concentration on the kinetics of the emulsifier-free emulsion polymerization of vinyl acetate and methyl acrylate were studied. The polymerizations were carried out using potassium persulfate as the initiator. Form the electron micrographs of the resulting lattices, monodisperse PVAc and PMA lattices with particle diameters varying between 149-443 mm and 112-497 nm, respectively were processed. Uniformity of particle size indicated that nucleation of stable particle occurs early in the polymerization process. The polymerization rate was found to be proportional to the 0.88 and 1.5 power of the initial monomer concentration of vinyl acetate and methyl acrylate, respectively. Higher monomer concentration results in fewer particles and larger final particle diameter. With increasing monomer solubility in water the size of particle decreases and its distribution broadens

  13. Enzyme-catalyzed hydrolysis of dentin adhesives containing a new urethane-based trimethacrylate monomer

    Science.gov (United States)

    Park, Jong-Gu; Ye, Qiang; Topp, Elizabeth M.; Spencer, Paulette

    2009-01-01

    A new trimethacrylate monomer with urethane-linked groups, 1,1,1-tri-[4-(methacryloxyethylamino-carbonyloxy)-phenyl]ethane (MPE), was synthesized, characterized, and used as a co-monomer in dentin adhesives. Dentin adhesives containing 2-hydroxyethyl methacrylate (HEMA, 45% w/w) and 2,2-bis[4(2-hydroxy-3-methacryloyloxy-propyloxy)-phenyl] propane (BisGMA, 30% w/w) in addition to MPE (25% w/w) were formulated with H2O at 0 (MPE0), 8 (MPE8) and 16 wt % water (MPE16) to simulate the wet demineralized dentin matrix and compared with controls [HEMA/BisGMA, 45/55 w/w, at 0 (C0), 8 (C8) and 16 wt% water (C16)]. The new adhesive showed a degree of double bond conversion and mechanical properties comparable with control, with good penetration into the dentin surface and a uniform adhesive/dentin interface. On exposure to porcine liver esterase, the net cumulative methacrylic acid (MAA) release from the new adhesives was dramatically (P < 0.05) decreased relative to the control, suggesting that the new monomer improves esterase resistance. PMID:19582843

  14. NGAL (Lcn2) monomer is associated with tubulointerstitial damage in chronic kidney disease.

    Science.gov (United States)

    Nickolas, Thomas L; Forster, Catherine S; Sise, Meghan E; Barasch, Nicholas; Solá-Del Valle, David; Viltard, Melanie; Buchen, Charles; Kupferman, Shlomo; Carnevali, Maria Luisa; Bennett, Michael; Mattei, Silvia; Bovino, Achiropita; Argentiero, Lucia; Magnano, Andrea; Devarajan, Prasad; Mori, Kiyoshi; Erdjument-Bromage, Hediye; Tempst, Paul; Allegri, Landino; Barasch, Jonathan

    2012-09-01

    The type and the extent of tissue damage inform the prognosis of chronic kidney disease (CKD), but kidney biopsy is not a routine test. Urinary tests that correlate with specific histological findings might serve as surrogates for the kidney biopsy. We used immunoblots and ARCHITECT-NGAL assays to define the immunoreactivity of urinary neutrophil gelatinase-associated lipocalin (NGAL) in CKD, and we used mass spectroscopy to identify associated proteins. We analyzed kidney biopsies to determine whether specific pathological characteristics associated with the monomeric NGAL species. Advanced CKD urine contained the NGAL monomer as well as novel complexes of NGAL. When these species were separated, we found a significant correlation between the NGAL monomer and glomerular filtration rate (r=-0.53, P<0.001), interstitial fibrosis (mild vs. severe disease; mean 54 vs. 167 μg uNGAL/g Cr, P<0.01), and tubular atrophy (mild vs. severe disease; mean 54 vs. 164 μg uNGAL/g Cr, P<0.01). Monospecific assays of the NGAL monomer demonstrated a correlation with histology that typifies progressive, severe CKD.

  15. Modification of polyethersulfone films by grafting hydrophilic monomers with 60Co γ-rays

    International Nuclear Information System (INIS)

    Hou Zhengchi; Deng Bo; Li Jing

    2006-01-01

    Polyethersulfone (PES), with its high strength, high temperature resistance, corrosion- resistance, oxidation resistance and applicability under wide pH range, is used extensively as ultrafiltration and nanofiltration membrane. However, PES membranes foul easily in such an application because of hydrophobic nature of PES raw materials. Improving the hydrophilicity of PES by grafting hydrophilic monomers onto it is of potential to solve the problem. At present, common approaches to improve hydrophilicity of PES membranes are UV grafting modification, plasma modification, and chemical modification, whereas grafting and modifying PES films by 60 Co γ-rays has rarely been reported. Studies have been carried out in our laboratory to graft hydrophilic monomers onto PES membranes directly or PES powders via simultaneous radiation grafting with the rays. Acrylic acid, methyl acrylic acid or acrylamide was used to study effects of the monomer concentration, irradiation dose and dose rate, solvent, inhibitor and pH of the grafting solution on the degree of grafting. The results showed that hydrophilicity of all the PES membranes could be improved, with the extent of improvement being dependent on the grafting conditions. (authors)

  16. Two Functionally Distinct Sources of Actin Monomers Supply the Leading Edge of Lamellipodia

    Science.gov (United States)

    Vitriol, Eric A.; McMillen, Laura M.; Kapustina, Maryna; Gomez, Shawn M.; Vavylonis, Dimitrios; Zheng, James Q.

    2015-01-01

    Summary Lamellipodia, the sheet-like protrusions of motile cells, consist of networks of actin filaments (F-actin) regulated by the ordered assembly from and disassembly into actin monomers (G-actin). Traditionally, G-actin is thought to exist as a homogeneous pool. Here, we show that there are two functionally and molecularly distinct sources of G-actin that supply lamellipodial actin networks. G-actin originating from the cytosolic pool requires the monomer binding protein thymosin β4 (Tβ4) for optimal leading edge localization, is targeted to formins, and is responsible for creating an elevated G/F-actin ratio that promotes membrane protrusion. The second source of G-actin comes from recycled lamellipodia F-actin. Recycling occurs independently of Tβ4 and appears to regulate lamellipodia homeostasis. Tβ4-bound G-actin specifically localizes to the leading edge because it doesn’t interact with Arp2/3-mediated polymerization sites found throughout the lamellipodia. These findings demonstrate that actin networks can be constructed from multiple sources of monomers with discrete spatiotemporal functions. PMID:25865895

  17. Emission spectra from super-critical rippled plasma density profiles illuminated by intense laser pulses

    International Nuclear Information System (INIS)

    Ondarza R, R.; Boyd, T.J.M.

    2000-01-01

    High-order harmonic emission from the interaction of intense femtosecond laser pulses with super-critical plasmas characterized by a rippled density profile at the vacuum-plasma interface has been observed from particle-in-cell (PIC) simulations. A plasma simulation box several laser wavelengths in extent was prepared with a rippled density of a fraction of a laser wavelength. Emission spectra at the very initial stage of the interaction were recorded with spectral characteristics dissimilar to those previously reported in the literature. The reflected light spectra were characterized by a strong emission at the plasma line and by a series of harmonics at multiples of the ripple frequency. Harmonic spectra were obtained for different values of the plasma ripple frequency. In all cases the harmonics were emitted at the precise multiple harmonic number of the ripple frequency. Another important feature apparent from the simulations was that the emission peaks appeared to havea complex structure as compared with those for unrippled plasmas. For the cases when the plasma was rippled the peaks that corresponded to the multiples of the rippled density typically showed a double peak for the first few harmonics. The reflected emission plots for the main laser pulse showed strong emission at the plasma frequency and at multiples of that frequency as reported by the authors in the literature. (Author)

  18. Complex-radical copolymerization of vinyl monomers on organoelemental initiators

    International Nuclear Information System (INIS)

    Grishin, D.F.

    1993-01-01

    Data on regularities of the initiation and growth of the (co)polymerization of polar vinyl series monomers on organo-elemental initiator, organo-boron in particular, are generalized. The effect of organo-metallic compounds and some phenol type inhibitors on the rate of acrylate (co)polymerization is analyzed from view of the change of electroacceptor properties (electrophilicity) of macroradicals

  19. N-Acetyl Cysteine Depletes Reactive Oxygen Species and Prevents Dental Monomer-Induced Intrinsic Mitochondrial Apoptosis In Vitro in Human Dental Pulp Cells.

    Directory of Open Access Journals (Sweden)

    Yang Jiao

    Full Text Available To investigate the involvement of intrinsic mitochondrial apoptosis in dental monomer-induced cytotoxicity and the influences of N-acetyl cysteine (NAC on this process.Human dental pulp cells (hDPCs were exposed to several dental monomers in the absence or presence of NAC, and cell viability, intracellular redox balance, morphology and function of mitochondria and key indicators of intrinsic mitochondrial apoptosis were evaluated using various commercial kits.Dental monomers exerted dose-dependent cytotoxic effects on hDPCs. Concomitant to the over-production of reactive oxygen species (ROS and depletion of glutathione (GSH, differential changes in activities of superoxide dismutase, glutathione peroxidase, and catalase were detected. Apoptosis, as indicated by positive Annexin V/propidium iodide (PI staining and activation of caspase-3, was observed after dental monomer treatment. Dental monomers impaired the morphology and function of mitochondria, and induced intrinsic mitochondrial apoptosis in hDPCs via up-regulation of p53, Bax and cleaved caspase-3, and down-regulation of Bcl-2. NAC restored cell viability, relieved oxidative stress and blocked the apoptotic effects of dental monomers.Dental monomers induced oxidative stress and mitochondrial intrinsic apoptosis in hDPCs. NAC could reduce the oxidative stress and thus protect hDPCs against dental monomer-induced apoptosis.

  20. Interactions between resin monomers and commercial composite resins with human saliva derived esterases.

    Science.gov (United States)

    Jaffer, F; Finer, Y; Santerre, J P

    2002-04-01

    Cholesterol esterase (CE) and pseudocholinesterase (PCE) have been reported to degrade commercial and model composite resins containing bisphenylglycidyl dimethacrylate (BisGMA), triethylene glycol dimethacrylate (TEGDMA) or the latter in combination with urethane modified BisGMA monomer systems. In addition, human saliva has been shown to contain esterase like activities similar to CE and PCE. Hence, it was the aim of the current study to determine to what extent human saliva could degrade two common commercial composite resins (Z250 from 3M Inc. and Spectrum TPH from L.D. Caulk) which contain the above monomer systems. Saliva samples from different volunteers were collected, processed, pooled, and freeze-dried. TEGDMA and BisGMA monomers were incubated with human saliva derived esterase activity (HSDEA) and their respective hydrolysis was monitored using high performance liquid chromatography (HPLC). Both monomers were completely hydrolyzed within 25 h by HSDEA. Photopolymerized composites were incubated with buffer or human saliva (pH 7.0 and 37 C) for 2, 8 and 16 days. The incubation solutions were analyzed using HPLC and mass spectrometry. Surface morphology characterization was carried out using scanning electron microscopy. Upon biodegradation, the Z250 composite yielded higher amounts of BisGMA and TEGDMA related products relative to the TPH composite. However, there were higher amounts of ethoxylated bis-phenol A released from the TPH material. In terms of total mass of products released, human saliva demonstrated a greater ability to degrade Z250. In summary, HSDEA has been shown to contain esterase activities that can readily catalyze the biodegradation of current commercial composite resins.

  1. Precision design of ethylene- and polar-monomer-based copolymers by organometallic-mediated radical polymerization

    Science.gov (United States)

    Kermagoret, Anthony; Debuigne, Antoine; Jérôme, Christine; Detrembleur, Christophe

    2014-03-01

    The copolymerization of ethylene with polar monomers is a major challenge when it comes to the manufacture of materials with potential for a wide range of commercial applications. In the chemical industry, free-radical polymerization is used to make a large proportion of such copolymers, but the forcing conditions result in a lack of fine control over the architecture of the products. Herein we introduce a synthetic tool, effective under mild experimental conditions, for the precision design of unprecedented ethylene- and polar-monomer-based copolymers. We demonstrate how an organocobalt species can control the growth of the copolymer chains, their composition and the monomer distribution throughout the chain. By fine tuning the ethylene pressure during polymerization and by exploiting a unique reactive mode of the end of the organometallic chain, novel block-like copolymer structures can be prepared. This highly versatile synthetic platform provides access to a diverse range of polymer materials.

  2. High monomer content batch microemulsion polymerization of butyl acrylate initiated with gamma ray

    Energy Technology Data Exchange (ETDEWEB)

    Chen Jun [Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China)]. E-mail: chjun04@mail.ustc.edu.cn; Zhang Zhicheng [Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China)]. E-mail: zczhang@ustc.edu.cn

    2007-05-15

    Radiation polymerization of butyl acrylate was performed in a microemulsion stabilized with a mixture of sodium of 12-acryloxy-9-octadecenoic acid and sodium dodecyl sulfate in a weight ratio of 2 at room temperature. BA content in microemulsion can be successfully improved up to 40 wt% with low surfactant concentration (lower than 10 wt%). The resulted stable, translucent microlatex contain particles with average diameter from 28.1 to 38.1 nm with different monomer content. Particle size depends on the dose rate and surfactant concentration. Effects of monomer content and dose rate on the maximum polymerization rate are discussed.

  3. Analysis of long-term monomer elution from bulk-fill and conventional resin-composites using high performance liquid chromatography.

    Science.gov (United States)

    Alshali, Ruwaida Z; Salim, Nesreen A; Sung, Rehana; Satterthwaite, Julian D; Silikas, Nick

    2015-12-01

    The aim of this study was to assess monomer elution from bulk-fill and conventional resin-composites stored in different media using high performance liquid chromatography (HPLC) for up to 3 months. Six bulk-fill (SureFil SDR, Venus Bulk Fill, X-tra base, Filtek Bulk Fill flowable, Sonic Fill, and Tetric EvoCeram Bulk Fill) and eight conventional resin-composites (Grandioso Flow, Venus Diamond Flow, X-Flow, Filtek Supreme XTE, Grandioso, Venus Diamond, TPH Spectrum, and Filtek Z250) were tested. Cylindrical samples (n=5) were immersed in water, 70% ethanol/water solution (70% E/W), and artificial saliva and stored at 37°C for 24h, 1 month, and 3 months. The storage solutions were analysed with HPLC. Data were analysed with repeated measures ANOVA, one-way ANOVA, and Tukey post hoc test at α=0.05. Monomers detected in water and artificial saliva were TEGDMA, DEGDMA, UDMA, and TCD-DI-HEA. No eluted monomers were detected from X-tra base and Sonic fill in these media. All monomers showed a variable extent of elution into 70% E/W with significantly higher amounts than those detected in water and artificial saliva. Significantly higher elution was detected from UDMA-BisEMA based composites compared to BisGMA and BisGMA-BisEMA based systems in 70% E/W. The rate of elution into different media varied between different monomers and was highly dependent on the molecular weight of the eluted compounds. Elution from bulk-fill resin-composites is comparable to that of conventional materials despite their increased increment thickness. Monomer elution is highly dependent on the hydrophobicity of the base monomers and the final network characteristics of the resin-matrix. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  4. Improving the circular economy via hydrothermal processing of high-density waste plastics.

    Science.gov (United States)

    Helmer Pedersen, Thomas; Conti, Federica

    2017-10-01

    Rising environmental concerns on climate changes are causing an increasing attention on circular economies. The plastic economy, in particular, is in focus due to the accelerating consumption of plastics, mainly derived from virgin feedstock, combined with the lack of plastic recycling strategies. This work presents a novel outlook on the potential of using supercritical hydrothermal processing of waste plastic fractions for tertiary recycling. The study investigates hydrothermal processing of nine different, high-density types of plastics into original resin monomers and other value-added chemical compounds. The outlook presents conversion yields, carbon balances, and chemical details on the products obtained. It is found that all the investigated resins are prone to hydrothermal treatment, and that high yields of monomers and high value compounds (up to nearly 100%), suitable for chemicals and fuels applications, can be obtained. For instance, for polycarbonate, styrene-butadiene, poly(lactic acid), poly(ethylene terephthalate), and poly(butylene terephthalate), original monomeric compounds can be reclaimed for manufacturing new resins. The promising results presented demonstrate that hydrothermal processing of high-density plastics is a prospective technology for increasing the circularity of the plastic economy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Luminal and parenteral TFF2 and TFF3 dimer and monomer in two models of experimental colitis in the rat

    DEFF Research Database (Denmark)

    Poulsen, Steen Seier; Kissow, Hannelouise; Hare, Kristine

    2005-01-01

    % dextran sodium sulphate in the drinking water or by one intraperitoneal injection of mitomycin C, 3.75 mg/kg. TFF peptides were administered as subcutaneous injections or directly into the lumen via a catheter placed in the proximal colon. Treatments were saline, TFF2, TFF3 monomer or TFF3 dimer 5 mg......2 had positive effect only in DSS-induced colitis. The TFF3 monomer was without any effects in both models. Treatment effect was most pronounced in the middle part of the colon, closest to the tip of the catheter. Injected TFF peptides, especially the TFF3 monomer, aggravated the colitis score...... in both colitis models. CONCLUSIONS: Intracolonic administration of TFF3 dimer and TFF2 improves experimentally induced colitis in rats. The TFF3 monomer has no effect. Parenteral administration of TFF peptides aggravates the colitis especially the TFF3 monomer....

  6. Effect of concentration of polyfunctional monomers on physical properties of acrylonitrile-butadiene rubber under electron-beam irradiation

    International Nuclear Information System (INIS)

    Yasin, T.; Ahmed, S.; Yoshii, F.; Makuuchi, K.

    2003-01-01

    The effect of concentration of different polyfunctional monomers (PFMs) on the physical properties of electron-beam irradiated acrylonitrile-butadiene rubber (NBR) has been investigated. The PFMs used were diethylene glycol dimethacrylate (2G), tetraethylene glycol dimethacrylate (4G), trimethylol propane triacrylate (A-TMPT), trimethylol propane trimethacrylate (TMPT) and tetramethylol methane tetraacrylate (A-TMMT). The physical properties of EB irradiated NBR sheets were evaluated by measurement of tensile strength, elongation %, hardness and gel fraction etc. The results show a remarkable increase in all physical properties as the concentration of PFMs increases from 1 phr to 5 phr in the NBR samples. The improvement in physical properties of radiation crosslinked NBR in the presence of PFMs may be attributed to its increased crosslinking density as observed by corresponding increase in gel content

  7. Proanthocyanidin profile of cowpea (Vigna unguiculata) reveals catechin-O-glucoside as the dominant compound.

    Science.gov (United States)

    Ojwang, Leonnard O; Yang, Liyi; Dykes, Linda; Awika, Joseph

    2013-08-15

    Proanthocyanidin (PA) profile and content can have important nutritional and health implications on plant foods. Six diverse cowpea phenotypes (black, red, green, white, light-brown and golden-brown) were investigated for PA composition using normal-phase HPLC and reversed-phase UPLC-TQD-MS. Catechin and (epi)afzelechin were the major flavan-3-ol units. Unusual composition was observed in all cowpea phenotypes with significant degrees of glycosylation in the monomers and dimers. The PA content of cowpea (dry basis) ranged between 2.2 and 6.3 mg/g. Monomeric flavan-3-ols were the largest group of PA (36-69%) in cowpea, with catechin-7-O-glucoside accounting for most (about 88%) of the monomers. The oligomers with degree of polymerization (DP) 2-4 ranged from 0.41 to 1.3 mg/g (15-20%), whereas DP>10 polymers accounted for only 13.5% of PA. Future studies that highlight the impact of the unusual cowpea PA profile on nutritional and bioactive properties of this important legume are warranted. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Pulse radiolysis study of monomer and dimer cations of styrene, 1-methylstyrene and 1,1'-diphenylethylene

    International Nuclear Information System (INIS)

    Mehnert, R.; Helmstreit, W.; Boes, J.; Brede, O.

    1977-01-01

    In pulse-irradiated solutions of styrene, 1-methylstyrene and 1,1'-diphenylethylene, the decay kinetics of the olefin monomer cations and the formation kinetics of the corresponding dimer cations have been studied at room temperature. The solutions were irradiated with 15-nsec 15-ampere pulses of 1-MeV electrons from an Elit-type accelerator. The total dose per pulse was approximately 10 krad. The monomer cations were generated with rate constants of about 10 11 M -1 sec -1 . From the time decay of the monomer light absorption and the growth in time of the dimer absorption rate constants for the dimer formation between 0.8x10 10 and 1.2x10 10 M -1 sec -1 have been determined. (T.I.)

  9. A New Inversion Routine to Produce Vertical Electron-Density Profiles from Ionospheric Topside-Sounder Data

    Science.gov (United States)

    Wang, Yongli; Benson, Robert F.

    2011-01-01

    Two software applications have been produced specifically for the analysis of some million digital topside ionograms produced by a recent analog-to-digital conversion effort of selected analog telemetry tapes from the Alouette-2, ISIS-1 and ISIS-2 satellites. One, TOPIST (TOPside Ionogram Scalar with True-height algorithm) from the University of Massachusetts Lowell, is designed for the automatic identification of the topside-ionogram ionospheric-reflection traces and their inversion into vertical electron-density profiles Ne(h). TOPIST also has the capability of manual intervention. The other application, from the Goddard Space Flight Center based on the FORTRAN code of John E. Jackson from the 1960s, is designed as an IDL-based interactive program for the scaling of selected digital topside-sounder ionograms. The Jackson code has also been modified, with some effort, so as to run on modern computers. This modification was motivated by the need to scale selected ionograms from the millions of Alouette/ISIS topside-sounder ionograms that only exist on 35-mm film. During this modification, it became evident that it would be more efficient to design a new code, based on the capabilities of present-day computers, than to continue to modify the old code. Such a new code has been produced and here we will describe its capabilities and compare Ne(h) profiles produced from it with those produced by the Jackson code. The concept of the new code is to assume an initial Ne(h) and derive a final Ne(h) through an iteration process that makes the resulting apparent-height profile fir the scaled values within a certain error range. The new code can be used on the X-, O-, and Z-mode traces. It does not assume any predefined profile shape between two contiguous points, like the exponential rule used in Jackson s program. Instead, Monotone Piecewise Cubic Interpolation is applied in the global profile to keep the monotone nature of the profile, which also ensures better smoothness

  10. Density Development During Erosion Experiments of Cohesive Sediments

    DEFF Research Database (Denmark)

    Johansen, Claus; Larsen, Torben

    1998-01-01

    The density development during erosion experiments was investigated. The calculation of the erosion rate requires the knowledge of the density profile with respect to the consolidation time(Parchure, 1984). At present, the basic assumption in the calculations is that the density profile is achiev...... in order to obtail time invariant sediment properties during the experiments....

  11. Permeability of different types of medical protective gloves to acrylic monomers.

    Science.gov (United States)

    Lönnroth, Emma-Christin; Wellendorf, Hanne; Ruyter, Eystein

    2003-10-01

    Dental personnel and orthopedic surgeons are at risk when manually handling products containing methyl methacrylate (MMA). Dental products may also contain cross-linking agents such as ethylene glycol dimethacrylate (EGDMA) or 1,4-butanediol dimethacrylate (1,4-BDMA). Skin contact with monomers can cause hand eczema, and the protection given by gloves manufactured from different types of material is not well known. The aim of this study was to determine the breakthrough time (BTT, min) as a measure of protection (according to the EU standard EN-374-3) for a mixture consisting of MMA, EGDMA and 1,4-BDMA. Fifteen different gloves representing natural rubber latex material, synthetic rubber material (e.g. nitrile rubbers), and synthetic polymer material were tested. The smallest monomer MMA permeated within 3 min through all glove materials. A polyethylene examination glove provided the longest protection period to EGDMA and 1, 4-BDMA (> 120 min and 25.0 min), followed by the surgical glove Tactylon (6.0 min and 8.7 min) and the nitrile glove Nitra Touch (5.0 min and 8.7 min). This study showed that the breakthrough time (based on permeation rate) cannot be regarded as a 'safe limit'. When the permeation rate is low, monomers may have permeated before BTT can be determined. Using double gloves with a synthetic rubber inner glove and a natural rubber outer glove provided longer protection when the inner glove was rinsed in water before placing the outer glove on top.

  12. Injection profiles with radiation induced copolymers

    International Nuclear Information System (INIS)

    Knight, B.L.; Rhudy, J.S.; Gogarty, W.B.

    1976-01-01

    The injectivity profile of a heterogeneous formation and/or vertical conformance is improved by injecting an aqueous solution into the formation, the solution containing a polymer obtained as a product of radiation-induced polymerization of acrylamide and/or methacrylamide and acrylic acid, methacrylic acid, and/or alkali metal salts thereof. The polymerization is preferably carried out in a 10 to 60 percent aqueous solution with gamma radiation; the aqueous monomer solution preferably contains 25 to 99 percent acrylamide and 1 to 75 percent sodium acrylate. Immiscible, miscible, or miscible-like displacing processes can be used in conjunction with this invention. 20 claims

  13. Dip-pen nanopatterning of photosensitive conducting polymer using a monomer ink

    Science.gov (United States)

    Su, Ming; Aslam, Mohammed; Fu, Lei; Wu, Nianqiang; Dravid, Vinayak P.

    2004-05-01

    Controlled patterning of conducting polymers at a micro- or nanoscale is the first step towards the fabrication of miniaturized functional devices. Here, we introduce an approach for the nanopatterning of conducting polymers using an improved monomer "ink" in dip-pen nanolithography (DPN). The nominal monomer "ink" is converted, in situ, to its conducting solid-state polymeric form after patterned. Proof-of-concept experiments have been performed with acid-promoted polymerization of pyrrole in a less reactive environment (tetrahydrofuran). The ratios of reactants are optimized to give an appropriate rate to match the operation of DPN. A similar synthesis process for the same polymer in its bulk form shows a high conductance and crystalline structure. The miniaturized conducting polymer sensors with light detection ability are fabricated by DPN using the improved ink formula, and exhibit excellent response, recovery, and sensitivity parameters.

  14. Dip-pen nanopatterning of photosensitive conducting polymer using a monomer ink

    International Nuclear Information System (INIS)

    Su Ming; Aslam, Mohammed; Fu Lei; Wu Nianqiang; Dravid, Vinayak P.

    2004-01-01

    Controlled patterning of conducting polymers at a micro- or nanoscale is the first step towards the fabrication of miniaturized functional devices. Here, we introduce an approach for the nanopatterning of conducting polymers using an improved monomer 'ink' in dip-pen nanolithography (DPN). The nominal monomer 'ink' is converted, in situ, to its conducting solid-state polymeric form after patterned. Proof-of-concept experiments have been performed with acid-promoted polymerization of pyrrole in a less reactive environment (tetrahydrofuran). The ratios of reactants are optimized to give an appropriate rate to match the operation of DPN. A similar synthesis process for the same polymer in its bulk form shows a high conductance and crystalline structure. The miniaturized conducting polymer sensors with light detection ability are fabricated by DPN using the improved ink formula, and exhibit excellent response, recovery, and sensitivity parameters

  15. Cyclic 3-alkyl pyridinium alkaloid monomers from a New Zealand Haliclona sp. marine sponge.

    Science.gov (United States)

    Damodaran, Vidhiya; Ryan, Jason L; Keyzers, Robert A

    2013-10-25

    Bioassay and NMR approaches have been used to guide the isolation of one known and two new cyclic 3-alkyl pyridinium alkaloid (3-APA) monomers from the New Zealand marine sponge Haliclona sp. The new compounds, dehydrohaliclocyclins C (3) and F (4), are the first reported examples of cyclic 3-APA monomers with unsaturation in the alkyl chain. The known compound haliclocyclin C (2) was also isolated from a mixture with 4. The structures of compounds 2-4 were elucidated using NMR spectroscopy, mass spectrometry, and chemical degradation.

  16. New aromatic activated dihalides and bisphenol monomers for the preparation of novel poly(arylene ethers)

    Science.gov (United States)

    Wolfe, James F.

    1993-01-01

    The goal of this research program was to synthesize a series of unique monomers of type I to be utilized at NASA-Langley in the preparation of new poly(arylene ether ketones), poly(arylene ether ketosulfones), and poly(arylene ether ketophosphine oxides). These A-A and A-B monomer systems, which possess activated aryl halide and/or phenolic end groups, are accessible via condensation reactions of appropriately substituted aryl acetonitrile carbanions with activated aryl dihalides followed by oxidative decyanation.

  17. Radiation initiated grafting of hydrophilic and reactive monomers on polyetherurethane for biomedical application

    International Nuclear Information System (INIS)

    Jansen, B.; Ellinghorst, G.

    1981-01-01

    Hydrogels such poly(hydroxyethylmethacrylate), poly (acrylamide) and poly(2,3-dihydroxypropylmethacrylate) are a class of well-known materials with good to excellent biomedical properties. Unfortunately the mechanical behaviour of the water-swollen gels is poor, and thus their application in pure state is limited. Much work has been done, especially by the grafting technique, on supporting the hydrogels by several techniques in order to improve their mechanical properties. In this work grafting of hydrogel forming or reactive monomers (which can be made hydrophilic by a following chemical process) onto a polyetherurethane was performed by a technique in which the trunk polymer is swollen in the graft monomer before irradiation. (author)

  18. Effect of microwave postpolymerization treatment on residual monomer content and the flexural strength of autopolymerizing reline resin

    Directory of Open Access Journals (Sweden)

    Patil Padmakar

    2009-01-01

    Full Text Available Background : Microwave postpolymerization has been suggested as a method to improve the flexural strength of an autopolymerizing denture reline resin. However, the effect of microwave postpolymerization on the residual monomer content and its influence on flexural strength have not been investigated. Objectives : This study analyzed the effect of microwave postpolymerization on the residual monomer content and its influence on the flexural strength of an autopolymerizing reline resin (Denture Liner. Materials and Methods : A total of 70 specimens (64 Χ 10 Χ 3.3 mm were polymerized according to the manufacturer′s instructions and divided into 7 groups (n = 10. Control group specimens were not subjectedto any further processing. Before testing, the specimens were subjected to postpolymerization in a microwave oven using different power (550 and 650 W and time (3, 4, and 5 min settings. Two specimens of each group were then manually ground into fine powder and samples extracted from the specimens using reflux method. The samples were then subjected to gas chromatography for residual monomer determination in area%. Eight specimens were subjected to a three-point bending device with a span of 50 mm and crosshead speed of 5 mm/min, and the flexural strength was determined in MPa. Data analyses included Student′s t-test and one-way analysis of variance. Results : For the Denture Liner reline resin, the residual monomer content decreased and the flexural strength increased significantly with the application of microwave irradiation using different time/power combinations. The specimens with the lowest residual monomer content were the similar specimens which presented with the highest flexural strength. Conclusion : Microwave postpolymerization irradiation can be an effective method for increasing the flexural strength of denture liner (at 650 W for 5 min by reducing the residual monomer content by further polymerization at free radical sites.

  19. Polyimide, dianhydride monomers, and polymers, methods of making and uses thereof

    KAUST Repository

    Pinnau, Ingo; Ghanem, Bader Saleh; Abdulhamid, Mahmoud Atef

    2017-01-01

    Embodiments of the present disclosure include, a dianhydride monomer, a polyimide, a method of making a dianhydride, a method of making a polyimide, and the like. Embodiments of the present disclosure can be used in membrane-based gas separation applications.

  20. Polyimide, dianhydride monomers, and polymers, methods of making and uses thereof

    KAUST Repository

    Pinnau, Ingo

    2017-11-16

    Embodiments of the present disclosure include, a dianhydride monomer, a polyimide, a method of making a dianhydride, a method of making a polyimide, and the like. Embodiments of the present disclosure can be used in membrane-based gas separation applications.

  1. Quantitative analysis of detailed lignin monomer composition by pyrolysis-gas chromatography combined with preliminary acetylation of the samples.

    Science.gov (United States)

    Sonoda, T; Ona, T; Yokoi, H; Ishida, Y; Ohtani, H; Tsuge, S

    2001-11-15

    Detailed quantitative analysis of lignin monomer composition comprising p-coumaryl, coniferyl, and sinapyl alcohol and p-coumaraldehyde, coniferaldehyde, and sinapaldehyde in plant has not been studied from every point mainly because of artifact formation during the lignin isolation procedure, partial loss of the lignin components inherent in the chemical degradative methods, and difficulty in the explanation of the complex spectra generally observed for the lignin components. Here we propose a new method to quantify lignin monomer composition in detail by pyrolysis-gas chromatography (Py-GC) using acetylated lignin samples. The lignin acetylation procedure would contribute to prevent secondary formation of cinnamaldehydes from the corresponding alcohol forms during pyrolysis, which are otherwise unavoidable in conventional Py-GC process to some extent. On the basis of the characteristic peaks on the pyrograms of the acetylated sample, lignin monomer compositions in various dehydrogenative polymers (DHP) as lignin model compounds were determined, taking even minor components such as cinnamaldehydes into consideration. The observed compositions by Py-GC were in good agreement with the supplied lignin monomer contents on DHP synthesis. The new Py-GC method combined with sample preacetylation allowed us an accurate quantitative analysis of detailed lignin monomer composition using a microgram order of extractive-free plant samples.

  2. Dimer monomer transition and dimer re-formation play important role for ATM cellular function during DNA repair

    International Nuclear Information System (INIS)

    Du, Fengxia; Zhang, Minjie; Li, Xiaohua; Yang, Caiyun; Meng, Hao; Wang, Dong; Chang, Shuang; Xu, Ye; Price, Brendan; Sun, Yingli

    2014-01-01

    Highlights: • ATM phosphorylates the opposite strand of the dimer in response to DNA damage. • The PETPVFRLT box of ATM plays a key role in its dimer dissociation in DNA repair. • The dephosphorylation of ATM is critical for dimer re-formation after DNA repair. - Abstract: The ATM protein kinase, is a serine/threonine protein kinase that is recruited and activated by DNA double-strand breaks, mediates responses to ionizing radiation in mammalian cells. Here we show that ATM is held inactive in unirradiated cells as a dimer and phosphorylates the opposite strand of the dimer in response to DNA damage. Cellular irradiation induces rapid intermolecular autophosphorylation of serine 1981 that causes dimer dissociation and initiates cellular ATM kinase activity. ATM cannot phosphorylate the substrates when it could not undergo dimer monomer transition. After DNA repair, the active monomer will undergo dephosphorylation to form dimer again and dephosphorylation is critical for dimer re-formation. Our work reveals novel function of ATM dimer monomer transition and explains why ATM dimer monomer transition plays such important role for ATM cellular activity during DNA repair

  3. Polar observations of electron density distribution in the Earth’s magnetosphere. 2. Density profiles

    Directory of Open Access Journals (Sweden)

    H. Laakso

    2002-11-01

    Full Text Available Using spacecraft potential measurements of the Polar electric field experiment, we investigate electron density variations of key plasma regions within the magnetosphere, including the polar cap, cusp, trough, plasmapause, and auroral zone. The statistical results were presented in the first part of this study, and the present paper reports detailed structures revealed by individual satellite passes. The high-altitude (> 3 RE polar cap is generally one of the most tenuous regions in the magnetosphere, but surprisingly, the polar cap boundary does not appear as a steep density decline. At low altitudes (1 RE in summer, the polar densities are very high, several 100 cm-3 , and interestingly, the density peaks at the central polar cap. On the noonside of the polar cap, the cusp appears as a dense, 1–3° wide region. A typical cusp density above 4 RE distance is between several 10 cm-3 and a few 100 cm-3 . On some occasions the cusp is crossed multiple times in a single pass, simultaneously with the occurrence of IMF excursions, as the cusp can instantly shift its position under varying solar wind conditions, similar to the magnetopause. On the nightside, the auroral zone is not always detected as a simple density cavity. Cavities are observed but their locations, strengths, and sizes vary. Also, the electric field perturbations do not necessarily overlap with the cavities: there are cavities with no field disturbances, as well as electric field disturbances observed with no clear cavitation. In the inner magnetosphere, the density distributions clearly show that the plasmapause and trough densities are well correlated with geomagnetic activity. Data from individual orbits near noon and midnight demonstrate that at the beginning of geomagnetic disturbances, the retreat speed of the plasmapause can be one L-shell per hour, while during quiet intervals the plasmapause can expand anti-earthward at the same speed. For the trough region, it is found

  4. Fueling with edge recycling to high-density in DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, A.W., E-mail: leonard@fusion.gat.com [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States); Elder, J.D. [University of Toronto Institute of Aerospace Studies, Toronto, Canada M3H 5T6 (Canada); Canik, J.M. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Groebner, R.J.; Osborne, T.H. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States)

    2013-07-15

    Pedestal fueling through edge recycling is examined with the interpretive OEDGE code for high-density discharges in DIII-D. A high current, high-density discharge is found to have a similar radial ion flux profile through the pedestal to a lower current, lower density discharge. The higher density discharge, however, has a greater density gradient indicating a pedestal particle diffusion coefficient that scales near linear with 1/I{sub p}. The time dependence of density profile is taken into account in the analysis of a discharge with low frequency ELMs. The time-dependent analysis indicates that the inferred neutral ionization source is inadequate to account for the increase in the density profile between ELMs, implying an inward density convection, or density pinch, near the top of the pedestal.

  5. Theory for the asymmetry in the auroral ionization density profile for the generation of auroral infrasonic waves

    International Nuclear Information System (INIS)

    Goodwin, P.A.

    1979-01-01

    Traveling pressure waves with periods from 10 to 100 seconds are generated in the lower ionosphere by auroral electrojet current filaments as they move supersonically in an equatorward direction. The infrasonic waves produced by the auroral motions propagate to the ground as highly directional bow waves that can be detected by infrasonic microphones on the surface. There is an asymmetry in the reception of auroral infrasonic waves (AIW) with respect to whether the auroral arcs are moving equatorward to poleward. In the literature it is suggested that the asymmetry may be due to anisotropic propagation conditions along the acoustic ray path from the E-region, where AIW are produced, to the surface. Some intrinsic property of the AIW generation mechanism itself has also been suggested as a possible explanation. In this thesis anisotropic propagation is eliminated as the cause of the AIW reception asymmetry. Theoretical calculations, beginning with a model of an auroral precipitation region, are presented to show that there can be a significant difference in the transverse ionization density profiles between an auroral arc that is moving equatorward and an arc that is moving poleward, for a given equatorward-directed E-region ambient electric field. The calculation has been accomplished by solving the equations of motion and continuity for the cross-sectional ionization density profile associated with the transverse motion of a filamentary auroral electrojet. Thus, it is shown that there is an asymmetry in the ionization profiles associated with moving arcs, and in their coupling, that is related to the relative direction of motion of the arc with respect to the ambient electric field, and that it is this asymmetry that is probably the cause of the observed AIW reception asymmetry

  6. Gamma irradiation effects on the grafting of low-density polyethylene with diethyl maleate

    International Nuclear Information System (INIS)

    Sanchez, Y.; Albano, C.; Karam, A.; Perera, R.; Silva, P.; Gonzalez, J.

    2005-01-01

    In this work, a low-density polyethylene (LDPE) was grafted with diethyl maleate (DEM) using gamma-rays from a Cobalt-60 source at different absorbed doses and monomer concentrations between 5 and 30 wt.%. This process was carried out in a decalin solution at 10 w/v% to obtain a homogeneous dispersion of the monomer into the polyethylene matrix. It was found that the grafting degree increases with the absorbed doses, as a consequence of the increased amount of energy given to the system, which made the grafting process more favorable. The grafting degree also increases with the concentration of DEM, because a higher concentration makes the insertion easier due to the increased availability of the free monomer. The highest grafting degree was obtained at 200 kGy of absorbed dose and with 30 wt.% of DEM. The melt flow index (MFI) values showed a decreasing trend as the absorbed dose was increased. This fact reveals that crosslinking and grafting are taking place simultaneously, this behavior being remarkable at higher irradiation doses. The results from thermogravimetric analysis (TGA) showed that the initial degradation temperatures remained almost unchanged with the absorbed dose

  7. Preparation of polyurethane foams using liquefied oil palm mesocarp fibre (OPMF) and renewable monomer from waste cooking oil

    Science.gov (United States)

    Kormin, Shaharuddin; Rus, Anika Zafiah M.; Azahari, M. Shafiq M.

    2017-09-01

    The aim of this research is the production of polyurethane (PU) foams with biopolyols from liquefied oil palm mesocarp fibre (OPMF) and renewable monomer. Liquefaction of OPMF was studied using polyhydric alcohol (PA) which is PEG-400 as liquefaction solvents in conventional glass flask. In the second part of this paper was obtained the PU foams which presented good results when compared with commercial foams and include polyols from of fossil fuels. PU foams were prepared by mixing liquefied OPMF biopolyol, renewable monomer from waste cooking, additives and methylene diphenyl diisocyanate (MDI). Water was used as an environmental friendly blowing agent. The factors that influence the cell structure of foams (i.e., catalyst, surfactant, dosage of blowing agent, and mass ratio of biopolyol to renewable monomer were studied. The synthesized PU foams were characterized by FTIR and SEM. The formulation of the PU foams should be improved, but the results show that is possible the use biopolyols and renewable monomer to produce industrial foams with lower cost.

  8. Kinetic behaviour of graft copolymerisation of nitrogenous heterocyclic monomer onto EB-irradiated ETFE films

    International Nuclear Information System (INIS)

    Paveswari Sithambaranathan; Arshad Ahmad; Mohamed Mahmoud Nasef; Universiti Teknologi Malaysia Campus, Kuala Lumpur

    2015-01-01

    Kinetic behaviour of graft copolymerisation of a nitrogenous heterocyclic monomer, 4-vinylpyridine (4-VP), onto electron beam irradiated poly(ethylene-co-tetrafluoroethylene) (ETFE) films was investigated in correlation with reaction parameters (absorbed dose, monomer concentration and reaction temperature). This was established by determination of initial polymerisation rate (r p0 ), characteristic radical recombination rate (γ) and delay time (t 0 ). The orders of the dependence of the initial rate of grafting on the absorbed dose and monomer concentration were found to be 2.28 and 3.49, respectively. The effect of temperature was investigated in the range of 50-70 deg C and the activation energy was determined. The incorporation of poly(4-VP) grafts and the accompanied chemical changes in the grafted ETFE films were monitored using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, respectively. The results of the present study showed that a quantitative kinetic description for grafting of 4-VP onto ETFE can be established and the degree of grafting can be tuned by controlling the reaction parameters. (author)

  9. Density structures inside the plasmasphere: Cluster observations

    DEFF Research Database (Denmark)

    Darrouzet, F.; Decreau, P.M.E.; De Keyser, J.

    2004-01-01

    The electron density profiles derived from the EFW and WHISPER instruments on board the four Cluster spacecraft reveal density structures inside the plasmasphere and at its outer boundary, the plasmapause. We have conducted a statistical study to characterize these density structures. We focus...... on the plasmasphere crossing on I I April 2002, during which Cluster observed several density irregularities inside the plasmasphere, as well as a plasmaspheric plume. We derive the density gradient vectors from simultaneous density measurements by the four spacecraft. We also determine the normal velocity...... of the boundaries of the plume and of the irregularities from the time delays between those boundaries in the four individual density profiles, assuming they are planar. These new observations yield novel insights about the occurrence of density irregularities, their geometry and their dynamics. These in...

  10. ON THE AVERAGE DENSITY PROFILE OF DARK-MATTER HALOS IN THE INNER REGIONS OF MASSIVE EARLY-TYPE GALAXIES

    International Nuclear Information System (INIS)

    Grillo, C.

    2012-01-01

    We study a sample of 39 massive early-type lens galaxies at redshift z ∼< 0.3 to determine the slope of the average dark-matter density profile in the innermost regions. We keep the strong-lensing and stellar population synthesis modeling as simple as possible to measure the galaxy total and luminous masses. By rescaling the values of the Einstein radius and dark-matter projected mass with the values of the luminous effective radius and mass, we combine all the data of the galaxies in the sample. We find that between 0.3 and 0.9 times the value of the effective radius the average logarithmic slope of the dark-matter projected density profile is –1.0 ± 0.2 (i.e., approximately isothermal) or –0.7 ± 0.5 (i.e., shallower than isothermal), if, respectively, a constant Chabrier or heavier, Salpeter-like stellar initial mass function is adopted. These results provide positive evidence of the influence of the baryonic component on the contraction of the galaxy dark-matter halos, compared to the predictions of dark-matter-only cosmological simulations, and open a new way to test models of structure formation and evolution within the standard ΛCDM cosmological scenario.

  11. The improved DGR analytical model of electron density height profile and total electron content in the ionosphere

    OpenAIRE

    Radicella, S. M.; Zhang, M. L.

    1995-01-01

    Tests of the analytical model of the electron density profile originally proposed by G, Di Giovanni and S.M. Radicella (DGR model) have shown the need to introduce improvements in order to obtain a model able to reproduce the ionosphere in a larger spectrum of geophysical and time conditions. The present paper reviews the steps toward such progress and presents the final formulation of the model. It gives also a brief re- view of tests of the improved model done by different authors.

  12. Influence of Monomer Concentration on the Morphologies and Electrochemical Properties of PEDOT, PANI, and PPy Prepared from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Shalini Kulandaivalu

    2016-01-01

    Full Text Available Poly(3,4-ethylenedioxyhiophene (PEDOT, polyaniline (PANI, and polypyrrole (PPy were prepared on indium tin oxide (ITO substrate via potentiostatic from aqueous solutions containing monomer and lithium perchlorate. The concentration of monomers was varied between 1 and 10 mM. The effects of monomer concentration on the polymers formation were investigated and compared by using Fourier transform infrared spectroscopy (FTIR, Raman spectroscopy, scanning electron microscopy (SEM, cyclic voltammetry (CV, and electrochemical impedance spectroscopy (EIS measurements. FTIR and Raman spectra showed no changes in the peaks upon the increment of the concentration. Based on the SEM images, the increment in monomer concentration gives significant effect on morphologies and eventually affects the electrochemical properties. PEDOT electrodeposited from 10 mM solution showed excellent electrochemical properties with the highest specific capacitance value of 12.8 mF/cm2.

  13. Immobilization of enzymes by radiation-induced polymerization of glass-forming monomers

    International Nuclear Information System (INIS)

    Yoshida, M.; Kumakura, M.; Kaetsu, I.

    1979-01-01

    The effect of cooling rate of a monomeric system on the porosity and activity of an immobilized enzyme prepared by radiation-induced polymerization of 2-hydroxyethyl methacrylate at low temperatures has been studied. Slow cooling gave the same effect on porosity of the polymer as decreasing the monomer concentration. A glass-forming solvent such as diethylene glycol was added to water to study the effect of the supercooling tendency of the solvent. Addition of diethylene glycol decreased porosity and also enzymic activity. Water was replaced by the miscible solvent p-dioxane and the immiscible solvent n-decane in order to clarify the effect of solvent. p-Dioxane had a similar effect to water on the relation between the monomer concentration, porosity and activity. On the other hand, polymer prepared from the system containing n-decane showed different immobilization properties owing to the presence of independent pores in the matrix. (author)

  14. Comparative study of the monomer grafting: ethylene, acetylene, 1,3-butadiene and estyrene in the matrix of recycled polytetrafluoroethylene (PTFE)

    International Nuclear Information System (INIS)

    Ikari, Carolina T.; Rosner, Gerhardyne O.; Oliveira, Ana C.F.; Ferreto, Helio F.R.; Lima, Luiz F.C.P.; Lugao, Ademar B.; Moreira, Otavio M.

    2009-01-01

    In this study it is used the recycled polytetrafluoroethylene (PTFE), that with the gamma radiation under inert atmosphere or in presence of air, it is obtained free radicals and a posterior the monomer grafting (ethylene, acetylene, styrene or 1.3 butadiene), obtaining the copolymer polytetrafluoroethylene-g-monomer. It is studied the obtention of the polymer by two methods: by direct way, via grafting, where the polymer is irradiated in presence of monomer, and via grafting when the polymer is irradiated in absence of monomer and under inert or air. The characterization of the copolymer was performed by the techniques of infrared region absorption spectroscopy with Fourier transformation (FTIR), thermogravimetric (TGA) and derivative thermogravimetry (DTG), and percentage of mass grafting (DOG)

  15. Graft copolymers of polypropylene films. 1. radiation induced grafting of mixed monomers. Vol. 3

    International Nuclear Information System (INIS)

    El-Salmawi, K.M.; El-Naggar, A.M.; Said, H.M.; Zahran, A.H.

    1996-01-01

    Radiation graft copolymerization of co monomer mixtures of acrylic acid (AAC), and styrene (S) onto polypropylene (PP) film by mutual method has been investigated. The effects of different factors that may affect the grafting yield such as inhibitor concentration (Mohr's salt), solvent composition (MeOH and H 2 O), radiation dose and dose rate were considered. It was found that the role of Mohr's salt is very effective when the ratio of AAC in the co monomer mixtures was at lower values. However, the addition of 1.25 Wt% of Mohr's salt reduced the homo polymer formation and enhances the grafting process. Graft copolymerization in presence of solvent mixture composed of methanol and water was found to afford higher grafting than in pure methanol regardless of the composition of the co monomer mixture used. However, the highest degree of grafting was obtained at a solvent composition of 20% H 2 O:80%MeOH and a co monomer mixture of 20%AAC:80%sty. An attempt was made to determine each PAAC and PS fractions in the total graft yield obtained. Two methods of analysis based on using the reactivity ratios reported in literature, elemental analysis and IR spectroscopy. The determination of poly (acrylic acid) and polystyrene fractions by elemental analysis is believed more accurate than these by reactivity ratio. The precise results obtained by elemental analysis with respect to the chemical structure of known polymer prepared under identical conditions. The results obtained by IR measurements go well with that obtained with the reactivity ratio methods. 5 figs., 3 tabs

  16. A new label dosimetry system based on pentacosa-diynoic acid monomer for low dose applications

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Fattah, A.A.; Abdel-Rehim, F. [National Center for Radiation Research and Technology, Atomic Energy Authority, P.O. Box 8029, Nasr City, Cairo (Egypt); Soliman, Y.S., E-mail: yasser_shabaan@hotmail.com [National Center for Radiation Research and Technology, Atomic Energy Authority, P.O. Box 8029, Nasr City, Cairo (Egypt)

    2012-01-15

    The dosimetric characteristics of {gamma}-radiation sensitive labels based on polyvinyl butyral (PVB) and a conjugated diacetylene monomer, 10,12-pentacosa-diynoic acid (PCDA) have been investigated using reflectance colorimeter. Two types of labels (colourless and yellow) based on PCDA monomer were prepared using an Automatic Film Applicator System. Upon {gamma}-ray exposure, the colourless label turns progressively blue, while the yellow colour label turns to green then to dark blue. The colour intensity of the labels is proportional to the radiation absorbed dose. The useful dose range was 15 Gy-2 kGy depending on PCDA monomer concentration. The expanded uncertainty of dose measurement of the colourless label was 6.06 (2{sigma}). - Highlights: > Using 10,12-pentacosa-diynoic acid (PCDA) in preparation of label dosimeter. > PCDA polymerises upon {gamma}-rays exposure producing a blue coloured polymer. > Useful dose range is 15 Gy to 2 kGy depending on concentration of PCDA. > Overall uncertainty of label dosimeter was 6.06 at 2{sigma}.

  17. Assembly of one-dimensional supramolecular objects: From monomers to networks

    Science.gov (United States)

    Sayar, Mehmet; Stupp, Samuel I.

    2005-07-01

    One-dimensional supramolecular aggregates can form networks at exceedingly low concentrations. Recent experiments in several laboratories, including our own, have demonstrated the formation of gels by these systems at concentrations well under 1% by weight. The systems of interest in our laboratory form either cylindrical nanofibers or ribbons as a result of strong noncovalent interactions among monomers. The stiffness and interaction energies among these thread-like objects can vary significantly depending on the chemical structure of the monomers used. We have used Monte Carlo simulations to study the structure of the threads and their ability to form networks through bundle formation. The persistence length of the threads was found to be strongly affected not only by stiffness, but also by the strength of attractive two-body interactions among thread segments. The relative values of stiffness and attractive two-body interaction strength determine if threads collapse or create bundles. Only in the presence of sufficiently long threads and bundle formation can these systems assemble into networks of high connectivity.

  18. Graft copolymerization of water soluble mixed monomers onto polyethylene by the pre-irradiation method

    International Nuclear Information System (INIS)

    Long Fu; Tang Liming; Zhao Jin; Gao Zhenyong

    1993-01-01

    Grafting of water soluble mixed monomers of acrylic acid (AA)/acrylamide (Am) and acrylic acid/methacrylic acid (MA) onto polyethylene film by the pre-irradiation grafting method was investigated. The results showed that the grafting proceeded successfully with the adding of ferric salt in the solution. In the case of AA/Am system, a synergistic effect was noticed. In the case of AA/MA system, the graft percent increased with the increase in the concentration of MA in the feed ratio. Furthermore, the effects of monomer concentration, radiation dose and temperature on the grafting were also studied

  19. Penelitian penggunaan monomer n-butil akrilat untuk peningkatan mutu kulit secara iradiasi

    Directory of Open Access Journals (Sweden)

    Dwi Wahini Nurhajati

    1996-06-01

    Full Text Available Research on the utilization of n-butyl acrylate monomer for quality improvement leather by irradiation cobalt-60 gamma-rays is carried out as follows: Javanese crust hide was impregnated with water emulsions of n-butyl acrylate monomer for 2 hours, packed in to poly ethylene bags, sealed, then irradiated by cobalt-60 gamma rays (doses : 5 to 25 kGy. The irradiated leather was washed by water, dried and then physical tested. The results of physical test of leather modified with n-butyl acrylate showed the increasing of tensile strength and elongation, decreasing of water absorption, resistance against the flexing test of 20,000 times, and PH was constant. Organoleptic test showed that the softly of the modified leather was no different with unmodified leather.

  20. Modeling the structure and vibrational spectra for oxouranium dichloride monomer and dimer

    Science.gov (United States)

    Umreiko, D. S.; Shundalau, M. B.; Trubina, O. V.

    2010-11-01

    Structural models are designed and spectral characteristics are computed for the monomer and dimer of the oxouranium dichloride (UOCl2) molecule based on ab initio calculations. The calculations were carried out in the LANL2DZ effective core potential approximation for the uranium atom and all-electron basis sets using DFT methods for oxygen and chlorine atoms (B3LYP/cc-pVDZ). A close-to-planar Y-shaped equilibrium configuration with Cs symmetry is obtained for the UOCl2 monomer. The formation of the dimer is accompanied by both significant changes in the structure of the monomeric fragments and the actual loss of their identities. The obtained spectral characteristics are analyzed and compared with experimental data. The adequacy of the proposed models and qualitative agreement between calculation and experiment are demonstrated.

  1. Effect of concentration of polyfunctional monomers on physical properties of acrylonitrile butadiene rubber under electron-beam irradiation

    Science.gov (United States)

    Yasin, Tariq; Ahmed, Shamshad; Ahmed, Munir; Yoshii, Fumio

    2005-06-01

    An investigation has been undertaken to find out the effect of concentration of different polyfunctional monomers (PFMs) on the physical properties of the acrylonitrile-butadiene rubber (NBR) crosslinked by electron beam (EB). The PFMs used were diethylene glycol dimethacrylate, trimethylol propane trimethacrylate and trimethylol propane triacrylate. The physical properties of EB-irradiated NBR sheets were evaluated by measuring the tensile strength, elongation percent at break, hardness and gel fraction. The results showed a remarkable increase in tensile strength, hardness and gel fraction as the concentration of PFMs was increased from 1 part per hundred (phr) to 5 phr in the NBR samples whereas elongation percent decreased in a steady manner. The improvement in physical properties of radiation crosslinked NBR in the presence of PFMs may be attributed to its increased crosslinking density as observed by the corresponding increase in gel content.

  2. Effect of concentration of polyfunctional monomers on physical properties of acrylonitrile-butadiene rubber under electron-beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yasin, Tariq [Polymer Processing and Radiation Technology Laboratory, Applied Chemistry Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan)]. E-mail: yasintariq@yahoo.com; Ahmed, Shamshad [Polymer Processing and Radiation Technology Laboratory, Applied Chemistry Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan); Ahmed, Munir [Polymer Processing and Radiation Technology Laboratory, Applied Chemistry Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan); Yoshii, Fumio [Takasaki Radiation Chemistry Research Establishment, JAERI, Takasaki, Gunma-Ken 370-12 (Japan)

    2005-06-01

    An investigation has been undertaken to find out the effect of concentration of different polyfunctional monomers (PFMs) on the physical properties of the acrylonitrile-butadiene rubber (NBR) crosslinked by electron beam (EB). The PFMs used were diethylene glycol dimethacrylate, trimethylol propane trimethacrylate and trimethylol propane triacrylate. The physical properties of EB-irradiated NBR sheets were evaluated by measuring the tensile strength, elongation percent at break, hardness and gel fraction. The results showed a remarkable increase in tensile strength, hardness and gel fraction as the concentration of PFMs was increased from 1 part per hundred (phr) to 5 phr in the NBR samples whereas elongation percent decreased in a steady manner. The improvement in physical properties of radiation crosslinked NBR in the presence of PFMs may be attributed to its increased crosslinking density as observed by the corresponding increase in gel content.

  3. Effect of concentration of polyfunctional monomers on physical properties of acrylonitrile-butadiene rubber under electron-beam irradiation

    International Nuclear Information System (INIS)

    Yasin, Tariq; Ahmed, Shamshad; Ahmed, Munir; Yoshii, Fumio

    2005-01-01

    An investigation has been undertaken to find out the effect of concentration of different polyfunctional monomers (PFMs) on the physical properties of the acrylonitrile-butadiene rubber (NBR) crosslinked by electron beam (EB). The PFMs used were diethylene glycol dimethacrylate, trimethylol propane trimethacrylate and trimethylol propane triacrylate. The physical properties of EB-irradiated NBR sheets were evaluated by measuring the tensile strength, elongation percent at break, hardness and gel fraction. The results showed a remarkable increase in tensile strength, hardness and gel fraction as the concentration of PFMs was increased from 1 part per hundred (phr) to 5 phr in the NBR samples whereas elongation percent decreased in a steady manner. The improvement in physical properties of radiation crosslinked NBR in the presence of PFMs may be attributed to its increased crosslinking density as observed by the corresponding increase in gel content

  4. Conformational alteration in alpha-toxin from Staphylococcus aureus concomitant with the transformation of the water-soluble monomer to the membrane oligomer.

    Science.gov (United States)

    Ikigai, H; Nakae, T

    1985-07-16

    The membrane-damaging alpha-toxin aggregate of Staphylococcus aureus was characterized physicochemically. The aggregate weight of the toxin formed by various methods appeared to be 6 times higher than the molecular weight of the monomer as determined by the laser light scattering technique, suggesting the presence of a hexamer in the membrane. The aggregates fluoresced 20 to 50% more than the monomer at 336 nm. Circular dichroism measurements revealed that both the monomer and the oligomer showed essentially beta-sheet structure with the maximum ellipticity about -8,400 deg.cm2.dmol-1 at 215 nm. Circular dichroism spectrum of the oligomers showed ellipticity difference of -6,600, -44 and +84 deg.cm2.dmol-1, at 200, 250 and 280 nm, respectively, compared with the monomer. All these results suggest that the conformational change in the toxin molecule occurs concomitant with the transformation of the water-soluble monomer to the membrane-embedded hexamer.

  5. Improving the Automatic Inversion of Digital Alouette/ISIS Ionogram Reflection Traces into Topside Electron Density Profiles

    Science.gov (United States)

    Benson, Robert F.; Truhlik, Vladimir; Huang, Xueqin; Wang, Yongli; Bilitza, Dieter

    2012-01-01

    The topside sounders of the International Satellites for Ionospheric Studies (ISIS) program were designed as analog systems. The resulting ionograms were displayed on 35 mm film for analysis by visual inspection. Each of these satellites, launched between 1962 and 1971, produced data for 10 to 20 years. A number of the original telemetry tapes from this large data set have been converted directly into digital records. Software, known as the Topside Ionogram Scalar With True-Height (TOPIST) algorithm, has been produced and used for the automatic inversion of the ionogram reflection traces on more than 100,000 ISIS-2 digital topside ionograms into topside vertical electron density profiles Ne(h). Here we present some topside ionospheric solar cycle variations deduced from the TOPIST database to illustrate the scientific benefit of improving and expanding the topside ionospheric Ne(h) database. The profile improvements will be based on improvements in the TOPIST software motivated by direct comparisons between TOPIST profiles and profiles produced by manual scaling in the early days of the ISIS program. The database expansion will be based on new software designed to overcome limitations in the original digital topside ionogram database caused by difficulties encountered during the analog-to-digital conversion process in the detection of the ionogram frame sync pulse and/or the frequency markers. This improved and expanded TOPIST topside Ne(h) database will greatly enhance investigations into both short- and long-term ionospheric changes, e.g., the observed topside ionospheric responses to magnetic storms, induced by interplanetary magnetic clouds, and solar cycle variations, respectively.

  6. Structural similarity between β(3)-peptides synthesized from β(3)-homo-amino acids and aspartic acid monomers.

    Science.gov (United States)

    Ahmed, Sahar; Sprules, Tara; Kaur, Kamaljit

    2014-07-01

    Formation of stable secondary structures by oligomers that mimic natural peptides is a key asset for enhanced biological response. Here we show that oligomeric β(3)-hexapeptides synthesized from L-aspartic acid monomers (β(3)-peptides 1, 5a, and 6) or homologated β(3)-amino acids (β(3)-peptide 2), fold into similar stable 14-helical secondary structures in solution, except that the former form right-handed 14-helix and the later form left-handed 14-helix. β(3)-Peptides from L-Asp monomers contain an additional amide bond in the side chains that provides opportunities for more hydrogen bonding. However, based on the NMR solution structures, we found that β(3)-peptide from L-Asp monomers (1) and from homologated amino acids (2) form similar structures with no additional side-chain interactions. These results suggest that the β(3)-peptides derived from L-Asp are promising peptide-mimetics that can be readily synthesized using L-Asp monomers as well as the right-handed 14-helical conformation of these β(3)-peptides (such as 1 and 6) may prove beneficial in the design of mimics for right-handed α-helix of α-peptides. © 2014 Wiley Periodicals, Inc.

  7. Monte Carlo neutral density calculations for ELMO Bumpy Torus

    International Nuclear Information System (INIS)

    Davis, W.A.; Colchin, R.J.

    1986-11-01

    The steady-state nature of the ELMO Bumpy Torus (EBT) plasma implies that the neutral density at any point inside the plasma volume will determine the local particle confinement time. This paper describes a Monte Carlo calculation of three-dimensional atomic and molecular neutral density profiles in EBT. The calculation has been done using various models for neutral source points, for launching schemes, for plasma profiles, and for plasma densities and temperatures. Calculated results are compared with experimental observations - principally spectroscopic measurements - both for guidance in normalization and for overall consistency checks. Implications of the predicted neutral profiles for the fast-ion-decay measurement of neutral densities are also addressed

  8. High-resolution structure of a retroviral protease folded as a monomer

    Czech Academy of Sciences Publication Activity Database

    Gilski, M.; Kazmierczyk, M.; Krzywda, S.; Zábranská, Helena; Cooper, S.; Popovic, Z.; Khatíb, F.; Dímaio, F.; Thompson, J.; Baker, D.; Pichová, Iva; Jaskolski, M.

    D67, č. 11 (2011), s. 907-914 ISSN 0907-4449 R&D Projects: GA MŠk 1M0508 Institutional research plan: CEZ:AV0Z40550506 Keywords : M-PMV protease * crystal structure * monomer * dimerization inhibitors Subject RIV: CE - Biochemistry Impact factor: 12.619, year: 2011

  9. Confinement bifurcation by current density profile perturbation in TUMAN-3M tokamak

    International Nuclear Information System (INIS)

    Lebedev, S.V.; Andreiko, M.V.; Askinazi, L.G.

    2001-01-01

    In the recent experiments performed on TUMAN-3M the possibility to switch on/off the H-mode by current density profile perturbations has been shown. The j(r) perturbations were created by fast Current Ramp Up/Down or by Magnetic Compression produced by a fast increase of the toroidal magnetic field. It was found that the Current Ramp Up (CRU) and Magnetic Compression (MC) are useful means for H-mode triggering. The Current Ramp Down (CRD) triggers H-L transition. The difference in the j(r) behavior in these experiments suggests the peripheral current density may not be the critical parameter controlling L-H and H-L transitions. Confinement bifurcation in the above experiments could be explained by the unified mechanism: variation of a turbulent transport resulting from radial electric field emerging near the edge in the conditions of alternating toroidal electric field Ej and different electron and ion collisionalities. According to the suggested model the toroidal field E φ arising in the periphery during the CRU and MC processes amplifies Ware drift, which mainly influences electron component. As a result the favorable for the transition negative (inward directed) E r emerges. In the CRD scenario, when E φ is opposite to the total plasma current direction, the mechanism should generate positive E r , which is thought to be unfavorable for the H-mode. The experimental data on L-H and H-L transitions in various scenarios and the results of the modeling of E r emerging in the CRU experiment are presented in the paper. (author)

  10. Graft copolymers of polypropylene films. 1. radiation induced grafting of mixed monomers. Vol. 3

    Energy Technology Data Exchange (ETDEWEB)

    El-Salmawi, K M; El-Naggar, A M; Said, H M; Zahran, A H [Radiation Chemistry Department, National Center for Radiation Research and Technology, Atomic Energy Authority, Cairo, (Egypt)

    1996-03-01

    Radiation graft copolymerization of co monomer mixtures of acrylic acid (AAC), and styrene (S) onto polypropylene (PP) film by mutual method has been investigated. The effects of different factors that may affect the grafting yield such as inhibitor concentration (Mohr`s salt), solvent composition (MeOH and H{sub 2} O), radiation dose and dose rate were considered. It was found that the role of Mohr`s salt is very effective when the ratio of AAC in the co monomer mixtures was at lower values. However, the addition of 1.25 Wt% of Mohr`s salt reduced the homo polymer formation and enhances the grafting process. Graft copolymerization in presence of solvent mixture composed of methanol and water was found to afford higher grafting than in pure methanol regardless of the composition of the co monomer mixture used. However, the highest degree of grafting was obtained at a solvent composition of 20% H{sub 2} O:80%MeOH and a co monomer mixture of 20%AAC:80%sty. An attempt was made to determine each PAAC and PS fractions in the total graft yield obtained. Two methods of analysis based on using the reactivity ratios reported in literature, elemental analysis and IR spectroscopy. The determination of poly (acrylic acid) and polystyrene fractions by elemental analysis is believed more accurate than these by reactivity ratio. The precise results obtained by elemental analysis with respect to the chemical structure of known polymer prepared under identical conditions. The results obtained by IR measurements go well with that obtained with the reactivity ratio methods. 5 figs., 3 tabs.

  11. An ionic force-field study of monomers, dimers and higher polymers in pentafluoride vapors

    Energy Technology Data Exchange (ETDEWEB)

    Cicek Onem, Z. [Department of Physics, Istanbul University, Istanbul (Turkey); Akdeniz, Z. [Department of Physics, Istanbul University, Istanbul (Turkey); Classe di Scienze, Scuola Normale Superiore, I-56126 Pisa (Italy)], E-mail: zakdeniz@istanbul.edu.tr; Tosi, M.P. [Classe di Scienze, Scuola Normale Superiore, I-56126 Pisa (Italy)], E-mail: tosim@sns.it

    2008-08-01

    Pentafluoride compounds such as NbF{sub 5} and TaF{sub 5} have been reported in the literature to admit various states of polymerization coexisting with monomers in their vapor phase, in relative concentrations that vary with temperature and pressure. We construct a microscopic interionic force-field model for the molecular monomer of these compounds (including VF{sub 5}, SbF{sub 5} and MoF{sub 5} in addition to NbF{sub 5} and TaF{sub 5}), the stable form of the monomer being in the shape of a D{sub 3h} trigonal bipyramid in all cases. The model emulates chemical bonds by allowing for electrical and short-range overlap polarizabilities of the fluorines, and is used to evaluate the structure and the stability of (MF{sub 5}){sub n} molecules with n running from 2 to 6. The dimer is formed by two distorted edge-sharing octahedral, while the trimer and the higher polymers can form rings of distorted corner-sharing octahedra. A chain-like configuration is also found for the trimer of NbF{sub 5}, which consists of a seven-fold coordinated Nb bonded to two distorted octahedra via edge sharing. Comparison of calculated vibrational frequencies and bond lengths with experimental data is made whenever possible. We find that there is a small net gain of energy in the formation of a dimer, while otherwise the static energy of the n-mer is very close to that of n separated monomers. High sensitivity of the state of molecular aggregation to the thermodynamic conditions of the vapor is clearly indicated by our calculations.

  12. Synthesis and spectroscopy of clay intercalated Cu(II) bio-monomer complexes: coordination of Cu(II) with purines and nucleotides

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Leeman, H.; Schoonheydt, R.A.

    1999-01-01

    The spectroscopic properties of Cu(bio-monomer)nm+ complexes [BM=bio-monomer (purine, adenine, guanine, hypoxanthine, 5-ADP and 5-GMP)] in saponite clays have been investigated by diffuse reflectance spectroscopy (DRS) in the UV-Vis-NIR region and electron paramagnetic resonance (EPR) at X-band.

  13. CLASH-VLT: The stellar mass function and stellar mass density profile of the z=0.44 cluster of galaxies MACS J1206.2-0847

    CERN Document Server

    Annunziatella, M; Mercurio, A.; Nonino, M.; Rosati, P.; Balestra, I.; Presotto, V.; Girardi, M.; Gobat, R.; Grillo, C.; Medezinski, E.; Kelson, D.; Postman, M.; Scodeggio, M.; Brescia, M.; Sartoris, B.; Demarco, R.; Fritz, A.; Koekemoer, A.; Lemze, D.; Lombardi, M.; Bradley, L.; Coe, D.; Donahue, M.; Regös, E.; Umetsu, K.; Vanzella, E.; Infante, L.; Kuchner, U.; Maier, C.; Verdugo, M.; Ziegler, B.

    2014-01-01

    Context. The study of the galaxy stellar mass function (SMF) in relation to the galaxy environment and the stellar mass density profile, rho(r), is a powerful tool to constrain models of galaxy evolution. Aims. We determine the SMF of the z=0.44 cluster of galaxies MACS J1206.2-0847 separately for passive and star-forming (SF) galaxies, in different regions of the cluster, from the center out to approximately 2 virial radii. We also determine rho(r) to compare it to the number density and total mass density profiles. Methods. We use the dataset from the CLASH-VLT survey. Stellar masses are obtained by SED fitting on 5-band photometric data obtained at the Subaru telescope. We identify 1363 cluster members down to a stellar mass of 10^9.5 Msolar. Results. The whole cluster SMF is well fitted by a double Schechter function. The SMFs of cluster SF and passive galaxies are statistically different. The SMF of the SF cluster galaxies does not depend on the environment. The SMF of the passive population has a signif...

  14. Effect of mineral acid on polymer produced during radiation-induced grafting of styrene monomer

    International Nuclear Information System (INIS)

    Garnett, J.L.; Jankiewicz, S.V.; Sangster, D.F.

    1982-01-01

    The inclusion of mineral acid in a solution of styrene in methanol subjected to 60 Co γ irradiation markedly enhances the yield of monomer grafted to cellulose and other radiation grafting systems. Results were reported from a preliminary investigation into the mechanism of this acid effect through a study of the action of acid during the solution polymerization process. It was found that the presence of acid in a monomer solution such as styrene in 1, 4-dioxan led to an enhancement in the homopolymer yield of styrene; and it was showed that the acid also effected the number-average molecular weight of this homopolymer. 1 figure, 4 tables

  15. Density limits in Tokamaks

    International Nuclear Information System (INIS)

    Tendler, M.

    1984-06-01

    The energy loss from a tokamak plasma due to neutral hydrogen radiation and recycling is of great importance for the energy balance at the periphery. It is shown that the requirement for thermal equilibrium implies a constraint on the maximum attainable edge density. The relation to other density limits is discussed. The average plasma density is shown to be a strong function of the refuelling deposition profile. (author)

  16. Derivation of the threshold condition for the ion temperature gradient mode with an inverted density profile from a simple physics picture

    Science.gov (United States)

    Jhang, Hogun

    2018-05-01

    We show that the threshold condition for the toroidal ion temperature gradient (ITG) mode with an inverted density profile can be derived from a simple physics argument. The key in this picture is that the density inversion reduces the ion compression due to the ITG mode and the electron drift motion mitigates the poloidal potential build-up. This condition reproduces the same result that has been reported from a linear gyrokinetic calculation [T. S. Hahm and W. M. Tang, Phys. Fluids B 1, 1185 (1989)]. The destabilizing role of trapped electrons in toroidal geometry is easily captured in this picture.

  17. Effects of nanoscale density inhomogeneities on shearing fluids

    DEFF Research Database (Denmark)

    Ben, Dalton,; Peter, Daivis,; Hansen, Jesper Schmidt

    2013-01-01

    It is well known that density inhomogeneities at the solid-liquid interface can have a strong effect on the velocity profile of a nanoconfined fluid in planar Poiseuille flow. However, it is difficult to control the density inhomogeneities induced by solid walls, making this type of system...... systems. Using the sinusoidal transverse force method to produce shearing velocity profiles and the sinusoidal longitudinal force method to produce inhomogeneous density profiles, we are able to observe the interactions between the two property inhomogeneities at the level of individual Fourier components....... This gives us a method for direct measurement of the coupling between the density and velocity fields and allows us to introduce various feedback control mechanisms which customize fluid behavior in individual Fourier components. We briefly discuss the role of temperature inhomogeneity and consider whether...

  18. A new label dosimetry system based on pentacosa-diynoic acid monomer for low dose applications

    International Nuclear Information System (INIS)

    Abdel-Fattah, A.A.; Abdel-Rehim, F.; Soliman, Y.S.

    2012-01-01

    The dosimetric characteristics of γ-radiation sensitive labels based on polyvinyl butyral (PVB) and a conjugated diacetylene monomer, 10,12-pentacosa-diynoic acid (PCDA) have been investigated using reflectance colorimeter. Two types of labels (colourless and yellow) based on PCDA monomer were prepared using an Automatic Film Applicator System. Upon γ-ray exposure, the colourless label turns progressively blue, while the yellow colour label turns to green then to dark blue. The colour intensity of the labels is proportional to the radiation absorbed dose. The useful dose range was 15 Gy-2 kGy depending on PCDA monomer concentration. The expanded uncertainty of dose measurement of the colourless label was 6.06 (2σ). - Highlights: → Using 10,12-pentacosa-diynoic acid (PCDA) in preparation of label dosimeter. → PCDA polymerises upon γ-rays exposure producing a blue coloured polymer. → Useful dose range is 15 Gy to 2 kGy depending on concentration of PCDA. → Overall uncertainty of label dosimeter was 6.06 at 2σ.

  19. Electron and current density measurements on tokamak plasmas

    International Nuclear Information System (INIS)

    Lammeren, A.C.A.P. van.

    1991-01-01

    The first part of this thesis describes the Thomson-scattering diagnostic as it was present at the TORTUR tokamak. For the first time with this diagnostic a complete tangential scattering spectrum was recorded during one single laser pulse. From this scattering spectrum the local current density was derived. Small deviations from the expected gaussian scattering spectrum were observed indicating the non-Maxwellian character of the electron-velocity distribution. The second part of this thesis describes the multi-channel interferometer/ polarimeter diagnostic which was constructed, build and operated on the Rijnhuizen Tokamak Project (RTP) tokamak. The diagnostic was operated routinely, yielding the development of the density profiles for every discharge. When ECRH (Electron Cyclotron Resonance Heating) is switched on the density profile broadens, the central density decreases and the total density increases, the opposite takes place when ECRH is switched off. The influence of MHD (magnetohydrodynamics) activity on the density was clearly observable. In the central region of the plasma it was measured that in hydrogen discharges the so-called sawtooth collapse is preceded by an m=1 instability which grows rapidly. An increase in radius of this m=1 mode of 1.5 cm just before the crash is observed. In hydrogen discharges the sawtooth induced density pulse shows an asymmetry for the high- and low-field side propagation. This asymmetry disappeared for helium discharges. From the location of the maximum density variations during an m=2 mode the position of the q=2 surface is derived. The density profiles are measured during the energy quench phase of a plasma disruption. A fast flattening and broadening of the density profile is observed. (author). 95 refs.; 66 figs.; 7 tabs

  20. Assessment risk of osteoporosis in Chinese people: relationship among body mass index, serum lipid profiles, blood glucose, and bone mineral density

    Directory of Open Access Journals (Sweden)

    Cui RT

    2016-07-01

    Full Text Available Rongtao Cui,1 Lin Zhou,2 Zuohong Li,2 Qing Li,2 Zhiming Qi,2 Junyong Zhang3 1Department of Orthopedic and Trauma Surgery, Surgical Research, Duisburg-Essen University Hospital, Essen, Germany; 2Department of Orthopedics, Dalian Central Hospital, Dalian, 3Department of Gastroenterology, Shandong Provincial Hospital, Jinan, People’s Republic of China Objective: The aim of our study was to investigate the relationship among age, sex, body mass index (BMI, serum lipid profiles, blood glucose (BG, and bone mineral density (BMD, making an assessment of the risk of osteoporosis.Materials and methods: A total of 1,035 male and 3,953 female healthy volunteers (aged 41–95 years were recruited by an open invitation. The basic information, including age, sex, height, weight, waistline, hipline, menstrual cycle, and medical history, were collected by a questionnaire survey and physical examination. Serum lipid profiles, BG, postprandial blood glucose, and glycosylated hemoglobin were obtained after 12 hours fasting. BMD in lumbar spine was measured by dual-energy X-ray absorptiometry scanning.Results: The age-adjusted BMD in females was significantly lower than in males. With aging, greater differences of BMD distribution exist in elderly females than in males (P<0.001, and the fastigium of bone mass loss was in the age range from 51 to 55 in females and from 61 to 65 years in males. After adjustment for sex, there were significant differences in BMD among BMI-stratified groups in both males and females. The subjects with a BMI of <18.5 had a higher incidence of osteoporosis than BMI ≥18.5 in both sexes. BMD in type 2 diabetes mellitus with a BG of >7.0 mmol/L was lower than in people with BG of ≤7.0 mmol/L (P<0.001. People with serum high-density lipoprotein cholesterol levels of ≥1.56 mmol/L had a greater prevalence of osteoporosis compared with high-density lipoprotein cholesterol ≤1.55 mmol/L. Logistic regression with odds ratios showed that

  1. 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.

  2. Vegetable oil-derived epoxy monomers and polymer blends: A comparative study with review

    Directory of Open Access Journals (Sweden)

    T. P. Schuman

    2013-03-01

    Full Text Available Glycidyl esters of epoxidized fatty acids derived from soybean oil (EGS and linseed oil (EGL have been synthesized to have higher oxirane content, more reactivity and lower viscosity than epoxidized soybean oil (ESO or epoxidized linseed oil (ELO. The EGS and ESO, for comparison, were used neat and in blends with diglycidyl ether of bisphenol A (DGEBA. Thermosetting resins were fabricated with the epoxy monomers and either BF3 catalyst or anhydride. The curing behaviors, glass transition temperatures, crosslink densities and mechanical properties were tested. The results indicated that polymer glass transition temperatures were mostly a function of oxirane content with additional influence of glycidyl versus internal oxirane reactivity, pendant chain content, and chemical structure and presence of saturated components. EGS provided better compatibility with DGEBA, improved intermolecular crosslinking and glass transition temperature, and yielded mechanically stronger polymerized materials than materials obtained using ESO. Other benefits of the EGS resin blend systems were significantly reduced viscosities compared to either DGEBA or ESO-blended DGEBA counterparts. Therefore, EGS that is derived from renewable sources has improved potential for fabrication of structural and structurally complex epoxy composites, e.g., by vacuum-assisted resin transfer molding.

  3. High performance dental resin composites with hydrolytically stable monomers.

    Science.gov (United States)

    Wang, Xiaohong; Huyang, George; Palagummi, Sri Vikram; Liu, Xiaohui; Skrtic, Drago; Beauchamp, Carlos; Bowen, Rafael; Sun, Jirun

    2018-02-01

    The objectives of this project were to: 1) develop strong and durable dental resin composites by employing new monomers that are hydrolytically stable, and 2) demonstrate that resin composites based on these monomers perform superiorly to the traditional bisphenol A glycidyl dimethacrylate/triethylene glycol dimethacrylate (Bis-GMA/TEGDMA) composites under testing conditions relevant to clinical applications. New resins comprising hydrolytically stable, ether-based monomer, i.e., triethylene glycol divinylbenzyl ether (TEG-DVBE), and urethane dimethacrylate (UDMA) were produced via composition-controlled photo-polymerization. Their composites contained 67.5wt% of micro and 7.5wt% of nano-sized filler. The performances of both copolymers and composites were evaluated by a battery of clinically-relevant assessments: degree of vinyl conversion (DC: FTIR and NIR spectroscopy); refractive index (n: optical microscopy); elastic modulus (E), flexural strength (F) and fracture toughness (K IC ) (universal mechanical testing); Knoop hardness (HK; indentation); water sorption (W sp ) and solubility (W su ) (gravimetry); polymerization shrinkage (S v ; mercury dilatometry) and polymerization stress (tensometer). The experimental UDMA/TEG-DVBE composites were compared with the Bis-GMA/TEGDMA composites containing the identical filler contents, and with the commercial micro hybrid flowable composite. UDMA/TEG-DBVE composites exhibited n, E, W sp , W su and S v equivalent to the controls. They outperformed the controls with respect to F (up to 26.8% increase), K IC (up to 27.7% increase), modulus recovery upon water sorption (full recovery vs. 91.9% recovery), and stress formation (up to 52.7% reduction). In addition, new composites showed up to 27.7% increase in attainable DC compared to the traditional composites. Bis-GMA/TEGDMA controls exceeded the experimental composites with respect to only one property, the composite hardness. Significantly, up to 18.1% lower HK values in

  4. Near-surface density profiling of Fe ion irradiated Si (100) using extremely asymmetric x-ray diffraction by variation of the wavelength

    Energy Technology Data Exchange (ETDEWEB)

    Khanbabaee, B., E-mail: khanbabaee@physik.uni-siegen.de; Pietsch, U. [Solid State Physics, University of Siegen, D-57068 Siegen (Germany); Facsko, S. [Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden (Germany); Doyle, S. [Synchrotron Light Source ANKA, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

    2014-10-20

    In this work, we report on correlations between surface density variations and ion parameters during ion beam-induced surface patterning process. The near-surface density variations of irradiated Si(100) surfaces were investigated after off-normal irradiation with 5 keV Fe ions at different fluences. In order to reduce the x-ray probing depth to a thickness below 5 nm, the extremely asymmetrical x-ray diffraction by variation of wavelength was applied, exploiting x-ray refraction at the air-sample interface. Depth profiling was achieved by measuring x-ray rocking curves as function of varying wavelengths providing incidence angles down to 0°. The density variation was extracted from the deviations from kinematical Bragg angle at grazing incidence angles due to refraction of the x-ray beam at the air-sample interface. The simulations based on the dynamical theory of x-ray diffraction revealed that while a net near-surface density decreases with increasing ion fluence which is accompanied by surface patterning, there is a certain threshold of ion fluence to surface density modulation. Our finding suggests that the surface density variation can be relevant with the mechanism of pattern formation.

  5. Axisymmetric instability of a self-pinched beam with rounded radial density profile

    International Nuclear Information System (INIS)

    Chen, H.C.; Uhm, H.S.

    1983-01-01

    The axisymmetric perturbations (sausage and hollowing modes) of an intense relativistic self-pinched electron beam propagating in a resistive plasma background are studied, especially for a beam with rounded radial density profile. The Bennett profiles are assumed for both the equilibrium beam current J/sub b/(r) = J/sub b/(0) (1+r 2 /R 2 /sub b/) -2 and plasma return current J/sub p/(r) = -fJ/sub b/(0) (1+r 2 /R 2 /sub p/) -2 , where R/sub b/ and R/sub p/ are the characteristic radii of the beam and plasma return currents, respectively. It is further assumed that the electric conductivity sigma(r) of the plasma channel is proportional to the return current. For a paraxial electron beam with complete space-charge neutralization by the ambient plasma, the axisymmetric modes can be destabilized by the phase lag between the magnetic field and beam current, even without the plasma return current. The plasma return current significantly modifies the growth rate of the instability such that the ratio of plasma current to beam current (-I/sub p//I/sub b/ = fR 2 /sub p// iR 2 /sub b/) largely determines the stability character of the beam. Furthermore, for the same fractional current neutralization f, the modes are highly unstable for a smaller ratio of plasma to beam radius R/sub p//R/sub b/. As compared to the resistive hose instability, the growth rates for the hollowing mode can be larger than those of the hose mode, while the sausage mode is much stabler than the hose mode. Stability properties are illustrated in detail for various system parameters

  6. Effect of increased exposure times on amount of residual monomer released from single-step self-etch adhesives.

    Science.gov (United States)

    Altunsoy, Mustafa; Botsali, Murat Selim; Tosun, Gonca; Yasar, Ahmet

    2015-10-16

    The aim of this study was to evaluate the effect of increased exposure times on the amount of residual Bis-GMA, TEGDMA, HEMA and UDMA released from single-step self-etch adhesive systems. Two adhesive systems were used. The adhesives were applied to bovine dentin surface according to the manufacturer's instructions and were polymerized using an LED curing unit for 10, 20 and 40 seconds (n = 5). After polymerization, the specimens were stored in 75% ethanol-water solution (6 mL). Residual monomers (Bis-GMA, TEGDMA, UDMA and HEMA) that were eluted from the adhesives (after 10 minutes, 1 hour, 1 day, 7 days and 30 days) were analyzed by high-performance liquid chromatography (HPLC). The data were analyzed using 1-way analysis of variance and Tukey HSD tests. Among the time periods, the highest amount of released residual monomers from adhesives was observed in the 10th minute. There were statistically significant differences regarding released Bis-GMA, UDMA, HEMA and TEGDMA between the adhesive systems (p<0.05). There were no significant differences among the 10, 20 and 40 second polymerization times according to their effect on residual monomer release from adhesives (p>0.05). Increasing the polymerization time did not have an effect on residual monomer release from single-step self-etch adhesives.

  7. Tractable flux-driven temperature, density, and rotation profile evolution with the quasilinear gyrokinetic transport model QuaLiKiz

    Science.gov (United States)

    Citrin, J.; Bourdelle, C.; Casson, F. J.; Angioni, C.; Bonanomi, N.; Camenen, Y.; Garbet, X.; Garzotti, L.; Görler, T.; Gürcan, O.; Koechl, F.; Imbeaux, F.; Linder, O.; van de Plassche, K.; Strand, P.; Szepesi, G.; Contributors, JET

    2017-12-01

    Quasilinear turbulent transport models are a successful tool for prediction of core tokamak plasma profiles in many regimes. Their success hinges on the reproduction of local nonlinear gyrokinetic fluxes. We focus on significant progress in the quasilinear gyrokinetic transport model QuaLiKiz (Bourdelle et al 2016 Plasma Phys. Control. Fusion 58 014036), which employs an approximated solution of the mode structures to significantly speed up computation time compared to full linear gyrokinetic solvers. Optimisation of the dispersion relation solution algorithm within integrated modelling applications leads to flux calculations × {10}6-7 faster than local nonlinear simulations. This allows tractable simulation of flux-driven dynamic profile evolution including all transport channels: ion and electron heat, main particles, impurities, and momentum. Furthermore, QuaLiKiz now includes the impact of rotation and temperature anisotropy induced poloidal asymmetry on heavy impurity transport, important for W-transport applications. Application within the JETTO integrated modelling code results in 1 s of JET plasma simulation within 10 h using 10 CPUs. Simultaneous predictions of core density, temperature, and toroidal rotation profiles for both JET hybrid and baseline experiments are presented, covering both ion and electron turbulence scales. The simulations are successfully compared to measured profiles, with agreement mostly in the 5%-25% range according to standard figures of merit. QuaLiKiz is now open source and available at www.qualikiz.com.

  8. Imprint of primordial non-Gaussianity on dark matter halo profiles

    Energy Technology Data Exchange (ETDEWEB)

    Dizgah, Azadeh Moradinezhad; Dodelson, Scott; Riotto, Antonio

    2013-09-01

    We study the impact of primordial non-Gaussianity on the density profile of dark matter halos by using the semi-analytical model introduced recently by Dalal {\\it et al.} which relates the peaks of the initial linear density field to the final density profile of dark matter halos. Models with primordial non-Gaussianity typically produce an initial density field that differs from that produced in Gaussian models. We use the path-integral formulation of excursion set theory to calculate the non-Gaussian corrections to the peak profile and derive the statistics of the peaks of non-Gaussian density field. In the context of the semi-analytic model for halo profiles, currently allowed values for primordial non-Gaussianity would increase the shapes of the inner dark matter profiles, but only at the sub-percent level except in the very innermost regions.

  9. The specific monomer/dimer equilibrium of the corticotropin-releasing factor receptor type 1 is established in the endoplasmic reticulum.

    Science.gov (United States)

    Teichmann, Anke; Gibert, Arthur; Lampe, André; Grzesik, Paul; Rutz, Claudia; Furkert, Jens; Schmoranzer, Jan; Krause, Gerd; Wiesner, Burkhard; Schülein, Ralf

    2014-08-29

    G protein-coupled receptors (GPCRs) represent the most important drug targets. Although the smallest functional unit of a GPCR is a monomer, it became clear in the past decades that the vast majority of the receptors form dimers. Only very recently, however, data were presented that some receptors may in fact be expressed as a mixture of monomers and dimers and that the interaction of the receptor protomers is dynamic. To date, equilibrium measurements were restricted to the plasma membrane due to experimental limitations. We have addressed the question as to where this equilibrium is established for the corticotropin-releasing factor receptor type 1. By developing a novel approach to analyze single molecule fluorescence cross-correlation spectroscopy data for intracellular membrane compartments, we show that the corticotropin-releasing factor receptor type 1 has a specific monomer/dimer equilibrium that is already established in the endoplasmic reticulum (ER). It remains constant at the plasma membrane even following receptor activation. Moreover, we demonstrate for seven additional GPCRs that they are expressed in specific but substantially different monomer/dimer ratios. Although it is well known that proteins may dimerize in the ER in principle, our data show that the ER is also able to establish the specific monomer/dimer ratios of GPCRs, which sheds new light on the functions of this compartment. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Fatty Acid-Based Monomers as Styrene Replacements for Liquid Molding Resins

    Science.gov (United States)

    2005-05-01

    fatty acid length and unsaturation level on resin and polymer properties. Fig. 2. The addition of fatty acids ( oleic acid ) to glycidyl methacylate to...the synthetic route used to form the methacrylated fatty acids (MFA). The carboxylic acid of fatty acids undergoes a simple addition reaction with... form methacrylated fatty acid monomer

  11. Preparation of poly (vinyl alcohol) membranes grafted with n-vinyl pyridine/ acrylic acid binary monomers

    International Nuclear Information System (INIS)

    Ajji, A.; Ali, A.

    2014-03-01

    Poly(vinyl alcohol) films were grafted with two monomers using gamma radiation, acrylic acid and N-vinyl pyridine. The influence of different parameters on the grafting yield was investigated as: the comonomer concentration and composition, and irradiation dose. The suitable conditions of the process had been determined to prepare PVA membranes have both properties of the two monomers, acrylic acid and vinyl pyridine as comonomer concentration and composition, and irradiation dose. Some properties of the membranes had been investigated as maximum swelling and grafting. Also the ability of the grafted films to adsorb some heavy metals and dyes was elaborated and discussed.(author)

  12. Slingshot mechanism for clusters: Gas density regulates star density in the Orion Nebula Cluster (M42)

    Science.gov (United States)

    Stutz, Amelia M.

    2018-02-01

    We characterize the stellar and gas volume density, potential, and gravitational field profiles in the central ∼0.5 pc of the Orion Nebula Cluster (ONC), the nearest embedded star cluster (or rather, protocluster) hosting massive star formation available for detailed observational scrutiny. We find that the stellar volume density is well characterized by a Plummer profile ρstars(r) = 5755 M⊙ pc- 3 (1 + (r/a)2)- 5/2, where a = 0.36 pc. The gas density follows a cylindrical power law ρgas(R) = 25.9 M⊙ pc- 3 (R/pc)- 1.775. The stellar density profile dominates over the gas density profile inside r ∼ 1 pc. The gravitational field is gas-dominated at all radii, but the contribution to the total field by the stars is nearly equal to that of the gas at r ∼ a. This fact alone demonstrates that the protocluster cannot be considered a gas-free system or a virialized system dominated by its own gravity. The stellar protocluster core is dynamically young, with an age of ∼2-3 Myr, a 1D velocity dispersion of σobs = 2.6 km s-1, and a crossing time of ∼0.55 Myr. This time-scale is almost identical to the gas filament oscillation time-scale estimated recently by Stutz & Gould. This provides strong evidence that the protocluster structure is regulated by the gas filament. The protocluster structure may be set by tidal forces due to the oscillating filamentary gas potential. Such forces could naturally suppress low density stellar structures on scales ≳ a. The analysis presented here leads to a new suggestion that clusters form by an analogue of the 'slingshot mechanism' previously proposed for stars.

  13. The Surface Density Profile of the Galactic Disk from the Terminal Velocity Curve

    Science.gov (United States)

    McGaugh, Stacy S.

    2016-01-01

    The mass distribution of the Galactic disk is constructed from the terminal velocity curve and the mass discrepancy-acceleration relation. Mass models numerically quantifying the detailed surface density profiles are tabulated. For R0 = 8 kpc, the models have stellar mass 5 spiral galaxy that obeys scaling relations like the Tully-Fisher relation, the size-mass relation, and the disk maximality-surface brightness relation. The stellar disk is maximal, and the spiral arms are massive. The bumps and wiggles in the terminal velocity curve correspond to known spiral features (e.g., the Centaurus arm is a ˜50% overdensity). The rotation curve switches between positive and negative over scales of hundreds of parsecs. The rms amplitude { }1/2≈ 14 {km} {{{s}}}-1 {{kpc}}-1, implying that commonly neglected terms in the Jeans equations may be nonnegligible. The spherically averaged local dark matter density is ρ0,DM ≈ 0.009 {M}⊙ {{pc}}-3 (0.34 {GeV} {{cm}}-3). Adiabatic compression of the dark matter halo may help reconcile the Milky Way with the c-V200 relation expected in ΛCDM while also helping to mitigate the too-big-to-fail problem, but it remains difficult to reconcile the inner bulge/bar-dominated region with a cuspy halo. We note that NGC 3521 is a near twin to the Milky Way, having a similar luminosity, scale length, and rotation curve.

  14. Semi-analytical study of the tokamak pedestal density profile in a single-null diverted plasma with puffing-recycling gas sources

    Science.gov (United States)

    Shi, Bingren

    2010-10-01

    The tokamak pedestal density structure is generally studied using a diffusion-dominant model. Recent investigations (Stacey and Groebner 2009 Phys. Plasmas 16 102504) from first principle based physics have shown a plausible existence of large inward convection in the pedestal region. The diffusion-convection equation with rapidly varying convection and diffusion coefficients in the near edge region and model puffing-recycling neutral particles is studied in this paper. A peculiar property of its solution for the existence of the large convection case is that the pedestal width of the density profile, qualitatively different from the diffusion-dominant case, depends mainly on the width of the inward convection and only weakly on the neutral penetration length and its injection position.

  15. Semi-analytical study of the tokamak pedestal density profile in a single-null diverted plasma with puffing-recycling gas sources

    Energy Technology Data Exchange (ETDEWEB)

    Shi Bingren, E-mail: shibr@swip.ac.c [Southwestern Institute of Physics, PO Box 432, Chengdu, Sichuan 610041 (China)

    2010-10-15

    The tokamak pedestal density structure is generally studied using a diffusion-dominant model. Recent investigations (Stacey and Groebner 2009 Phys. Plasmas 16 102504) from first principle based physics have shown a plausible existence of large inward convection in the pedestal region. The diffusion-convection equation with rapidly varying convection and diffusion coefficients in the near edge region and model puffing-recycling neutral particles is studied in this paper. A peculiar property of its solution for the existence of the large convection case is that the pedestal width of the density profile, qualitatively different from the diffusion-dominant case, depends mainly on the width of the inward convection and only weakly on the neutral penetration length and its injection position.

  16. New Vary-Chap Profile of the Topside Ionosphere Electron Density Distribution for use with the IRI Model and the GIRO Real-Time Data

    Science.gov (United States)

    Nsumei, Patrick; Reinisch, Bodo W.; Huang, Xueqin; Bilitza, Dieter

    2012-01-01

    A new Vary-Chap function is introduced for the empirical modeling of the electron density N(h) profile in the topside ionosphere that uses a shape function S(h) in the generalized Chapman function. The Vary-Chap profile extends the bottomside profile that is specified by the IRI model or measured by the Global Ionospheric Radio Observatory (GIRO) to the altitude of the ISIS-2 satellite. Some 80,000 topside profiles, measured by the topside sounder on the ISIS-2 satellite were analyzed, and the shape function S(h) was calculated for each profile. A parameterized function S*(h), composed of two sub-functions S1(h) and S2(h), is fitted to the measured S(h) profile using three free parameters. At altitudes just above the F2 layer peak height hmF2, the shape function S1 controls S(h), and at greater altitudes S2 controls S(h). The height of the intersection of S1 and S2 is defined as the transition height h(sub T) indicating the transition from an O(+) to an H(+)-dominated profile shape. The observed transition heights range from approx.500 km to 800 km.

  17. Biocatalytic synthesis and polymerization via ROMP of new biobased phenolic monomers: a greener process towards sustainable antioxidant polymers

    Science.gov (United States)

    Diot-Néant, Florian; Migeot, Loïs; Hollande, Louis; Reano, Felix A.; Domenek, Sandra; Allais, Florent

    2017-12-01

    Antioxidant norbornene-based monomers bearing biobased sterically hindered phenols (SHP) - NDF (norbornene dihydroferulate) and NDS (norbornene dihydrosinapate) - have been successfully prepared through biocatalysis from naturally occurring ferulic and sinapic acids, respectively, in presence of Candida antarctica Lipase B (Cal-B). The ring opening metathesis polymerization (ROMP) of these monomers was investigated according to ruthenium catalyst type (GI) vs. (HGII) and monomer to catalyst molar ratio ([M]/[C]). The co-polymerization of antioxidant functionalized monomer (NDF or NDS) and non-active norbornene (N) has also been performed in order to adjust the number of SHP groups present per weight unit and tune the antioxidant activity of the copolymers. The polydispersity of the resulting copolymers was readily improved by a simple acetone wash to provide antioxidant polymers with well-defined structures. After hydrogenation with p-toluenesulfonylhydrazine (p-TSH), the radical scavenging ability of the resulting saturated polymers was evaluated using α,α-diphenyl-β-picrylhydrazyl (DPPH) analysis. Results demonstrated that polymers bearing sinapic acid SHP exhibited higher antiradical activity than the polymer bearing ferulic acid SHP. In addition it was also shown that only a small SHP content was needed in the copolymers to exhibit a potent antioxidant activity.

  18. CO2 laser imaging heterodyne and phase contrast interferometer for density profile and fluctuation measurements in LHD

    International Nuclear Information System (INIS)

    Tanaka, K.; Michael, C.; Akiyama, T.; Kawahata, K.; Ito, Y.; Vyacheslavov, L.N.; Sanin, A.L.; Okajima, S.

    2007-01-01

    A CO 2 laser heterodyne imaging interferometer (CO 2 HI) and a CO 2 laser phase contrast imaging interferometer (CO 2 PCI) were installed in LHD. The purpose of CO 2 HI is to measure electron density profile at high density (>1x10 20 m -3 ), where the existing far infrared laser (wavelength 118.9 μm) interferometer suffers from fringe jump due to the reduction of signal intensity caused by refraction. In the beginning of 10th LHD experimental campaign (2006-2007), sixty three three of CO 2 HI with 10 channels of YAG HI for vibration compensation, and in the later of 10th LHD experimental campaign. Eighty one channels CO 2 HI and 15 channels YAG HI became available. The purpose of CO 2 PCI is to measure turbulent fluctuation, which can contribute to the energy and particle transport. In order to get local fluctuation information, magnetic shear technique was applied with use of 48 (6 by 8) channel two dimensional detector. (author)

  19. Density functional theory study on aqueous aluminum-fluoride complexes: exploration of the intrinsic relationship between water-exchange rate constants and structural parameters for monomer aluminum complexes.

    Science.gov (United States)

    Jin, Xiaoyan; Qian, Zhaosheng; Lu, Bangmei; Yang, Wenjing; Bi, Shuping

    2011-01-01

    Density functional theory (DFT) calculation is carried out to investigate the structures, (19)F and (27)Al NMR chemical shifts of aqueous Al-F complexes and their water-exchange reactions. The following investigations are performed in this paper: (1) the microscopic properties of typical aqueous Al-F complexes are obtained at the level of B3LYP/6-311+G**. Al-OH(2) bond lengths increase with F(-) replacing inner-sphere H(2)O progressively, indicating labilizing effect of F(-) ligand. The Al-OH(2) distance trans to fluoride is longer than other Al-OH(2) distance, accounting for trans effect of F(-) ligand. (19)F and (27)Al NMR chemical shifts are calculated using GIAO method at the HF/6-311+G** level relative to F(H(2)O)(6)(-) and Al(H(2)O)(6)(3+) references, respectively. The results are consistent with available experimental values; (2) the dissociative (D) activated mechanism is observed by modeling water-exchange reaction for [Al(H(2)O)(6-i)F(i)]((3-i)+) (i = 1-4). The activation energy barriers are found to decrease with increasing F(-) substitution, which is in line with experimental rate constants (k(ex)). The log k(ex) of AlF(3)(H(2)O)(3)(0) and AlF(4)(H(2)O)(2)(-) are predicted by three ways. The results indicate that the correlation between log k(ex) and Al-O bond length as well as the given transmission coefficient allows experimental rate constants to be predicted, whereas the correlation between log k(ex) and activation free energy is poor; (3) the environmental significance of this work is elucidated by the extension toward three fields, that is, polyaluminum system, monomer Al-organic system and other metal ions system with high charge-to-radius ratio.

  20. Design, synthesis and characterization of a highly luminescent Eu-complex monomer featuring thenoyltrifluoroacetone and 5-acryloxyethoxymethyl-8-hydroxyquinoline

    Energy Technology Data Exchange (ETDEWEB)

    Xu Cunjin [State Key Laboratory of Chemical Engineering, Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027 (China); College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036 (China); Li Bogeng, E-mail: bgli@zju.edu.cn [State Key Laboratory of Chemical Engineering, Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027 (China); Wan Jintao; Bu Zhiyang [State Key Laboratory of Chemical Engineering, Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027 (China)

    2011-08-15

    A multi-functional ligand, 5-acryloxyethoxymethyl-8-hydroxyquinoline (Hamq), was synthesized, which contained a polymerizable C=C double bond for the copolymerization with other vinyl monomers and acted as photon antenna able to transfer energy to Eu{sup 3+} ions effectively. The triplet state energy of Hamq was determined to be 22,370 cm{sup -1} via the phosphorescence spectra of Hamq and its gadolinium complex. The title complex monomer Eu(tta){sub 2}(amq) was prepared by coordination reaction of Hamq with europium isopropoxide and 2-thenoyltrifluoroacetone (Htta) in dry organic solvents under argon atmosphere and characterized by elemental analysis and IR spectrum. The photophysical properties of the complex were studied in detail with UV-vis, luminescence spectra, luminescence lifetime and quantum yield. The complex exhibited nearly monochromatic red emission at 612 nm, a remarkable luminescence quantum yield at room temperature (30.6%) upon ligand excitation and a long {sup 5}D{sub 0} lifetime (389 {mu}s), which indicated that the ligand Hamq could sensitize the luminescence of Eu(III) ion efficiently in Eu(tta){sub 2}(amq), resulting in a strong luminescence of its copolymer poly[MMA-co-Eu(TTA){sub 2}(amq)] under UV excitation. The excellent luminescence properties of the complex made it not only a promising light-conversion molecular device but also an excellent luminescent monomer. - Highlights: >iWe designed and synthesized a highly luminescent Eu-complex monomer. > Quantum yield and lifetime of the complex are 30.6% and 389 {mu}s, respectively. > Excellent luminescence of the complex made it an excellent luminescent monomer.