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Sample records for cavity formation solute

  1. Formation of cavities in Si and their chemisorption of metals

    International Nuclear Information System (INIS)

    Nanometer-size cavities formed in Si by He+ implantation and annealing are examined with cross-section TEM. During annealing at 700 C or above, He degasses from the specimens, leaving uhv cavities with reactive Si bonds on their walls. Cavity microstructures have been characterized in detail for an implanted fluence of 1 x 1017 He/cm2: cavity volume remains approximately constant (0.75 lattice sites/He) for anneals from 700 to ∼1000 C, while surface area (3 to 7 times the wafer area) decreases with temperature as the cavities coarsen. The cavities are found to getter up to ∼1 monolayer of Cu or Au from solution in Si without second-phase formation, thus identifying the trapping mechanism as chemisorption on the cavity walls

  2. Cavities Formation in Sedimentary Deposits

    Czech Academy of Sciences Publication Activity Database

    Kulaviak, Lukáš; Růžička, Marek; Drahoš, Jiří; Hladil, Jindřich

    Bratislava: Slovak Society of Chemical Engineering , 2008 - (Markoš, J.), s. 241 ISBN 978-80-227-2903-1. [35th International Conference of Slovak Society of Chemical Engineering . Tatranské Matliare (SK), 26.05.2008-30.05.2008] R&D Projects: GA ČR GA104/07/1110; GA ČR GA104/06/1418; GA AV ČR IAAX00130702; GA ČR GP104/06/P287 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z30130516 Keywords : suspension * cavities * stromatactis Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  3. Main features of nucleation in model solutions of oral cavity

    Science.gov (United States)

    Golovanova, O. A.; Chikanova, E. S.; Punin, Yu. O.

    2015-05-01

    The regularities of nucleation in model solutions of oral cavity have been investigated, and the induction order and constants have been determined for two systems: saliva and dental plaque fluid (DPF). It is shown that an increase in the initial supersaturation leads to a transition from the heterogeneous nucleation of crystallites to a homogeneous one. Some additives are found to enhance nucleation: HCO{3/-} > C6H12O6 > F-, while others hinder this process: protein (casein) > Mg2+. It is established that crystallization in DPF occurs more rapidly and the DPF composition is favorable for the growth of small (52.6-26.1 μm) crystallites. On the contrary, the conditions implemented in the model saliva solution facilitate the formation of larger (198.4-41.8 μm) crystals.

  4. Cavity formation by hydrogen injection in electron-irradiated austenitic stainless steel

    International Nuclear Information System (INIS)

    Thin foil specimens of solution annealed Type 316, 316L and Ti-modified 316L steels, cold worked Type 316 steel, and 1 MV electron-irradiated Type 316 steel are injected with hydrogen ions to 3x1021-9x1021 ions/m2 at 673 K. A number of cavities are formed not only in the matrix but also on grain boundaries in all the solution annealed steels. In the 5% cold worked 316 steel, the cavity number density is more reduced than in the solution annealed 316 steel. Cavity formation in 1 MV electron irradiated regions depends sensitively on electron predamage given prior to hydrogen ion injection. From a comparison of the cavity formations in electron irradiated regions with predamaged structures, it is noted that vacancy clusters interact strongly with hydrogen atoms and that tangled dislocation networks enable hydrogen atom transport to the foil surface. (orig.)

  5. Cavity formation by the impact of Leidenfrost spheres

    KAUST Repository

    Marston, Jeremy

    2012-05-01

    We report observations of cavity formation and subsequent collapse when a heated sphere impacts onto a liquid pool. When the sphere temperature is much greater than the boiling point of the liquid, we observe an inverted Leidenfrost effect where the sphere is encompassed by a vapour layer that prevents physical contact with the liquid. This creates the ultimate non-wetting scenario during sphere penetration through a free surface, producing very smooth cavity walls. In some cases during initial entry, however, the liquid contacts the sphere at the equator, leading to the formation of a dual cavity structure. For cold sphere impacts, where a contact line is observed, we reveal details of the contact line pinning, which initially forms a sawtooth pattern. We also observe surface waves on the cavity interface for cold spheres. We compare our experimental results to previous studies of cavity dynamics and, in particular, the influence of hydrophobicity on the entry of the sphere. © 2012 Cambridge University Press.

  6. Structural behavior of progressively mined solution cavities in salt

    International Nuclear Information System (INIS)

    The stress field and the time dependent deformation around a solution cavity in rock salt are shown to be sensitive to the details of the excavation process and to the prevailing tectonic stress field. An analysis procedure is developing whereby an incremental excavation procedure and a creep routine are incorporated simultaneously into an axisymmetric finite element code

  7. The structure of polaronic electron cavities in lithium-ammonia solutions

    International Nuclear Information System (INIS)

    Neutron diffraction has been used in conjunction with isotopic substitution of deuterium for hydrogen to study the structure of lithium-ammonia solutions, at concentrations spanning the metal-nonmetal transition. Detailed analysis and visualization of our experimental data has been carried out via iterative refinement of a three-dimensional molecular model, allowing us to obtain unique insight into the formation of polaronic electron cavities in the solutions. At low electron concentrations the solutions are nonmetallic, and the ammonia molecules are orientated around cavity centres to form Bjerrum-type defects. As the electron content is increased, the solutions become metallic, and we find evidence of percolation channels through the solvent. The dissociated electrons therefore play an active role in determining the structure of these solutions, and serve to disrupt the hydrogen bonding present in liquid ammonia

  8. Water entry without surface seal: Extended cavity formation

    KAUST Repository

    Mansoor, Mohammad M.

    2014-03-01

    We report results from an experimental study of cavity formation during the impact of superhydrophobic spheres onto water. Using a simple splash-guard mechanism, we block the spray emerging during initial contact from closing thus eliminating the phenomenon known as \\'surface seal\\', which typically occurs at Froude numbers Fr= V0 2/(gR0) = O(100). As such, we are able to observe the evolution of a smooth cavity in a more extended parameter space than has been achieved in previous studies. Furthermore, by systematically varying the tank size and sphere diameter, we examine the influence of increasing wall effects on these guarded impact cavities and note the formation of surface undulations with wavelength λ =O(10)cm and acoustic waves λa=O(D0) along the cavity interface, which produce multiple pinch-off points. Acoustic waves are initiated by pressure perturbations, which themselves are generated by the primary cavity pinch-off. Using high-speed particle image velocimetry (PIV) techniques we study the bulk fluid flow for the most constrained geometry and show the larger undulations ( λ =O (10cm)) have a fixed nature with respect to the lab frame. We show that previously deduced scalings for the normalized (primary) pinch-off location (ratio of pinch-off depth to sphere depth at pinch-off time), Hp/H = 1/2, and pinch-off time, τ α (R0/g) 1/2, do not hold for these extended cavities in the presence of strong wall effects (sphere-to-tank diameter ratio), ε = D 0/Dtank 1/16. Instead, we find multiple distinct regimes for values of Hp/H as the observed undulations are induced above the first pinch-off point as the impact speed increases. We also report observations of \\'kinked\\' pinch-off points and the suppression of downward facing jets in the presence of wall effects. Surprisingly, upward facing jets emanating from first cavity pinch-off points evolve into a \\'flat\\' structure at high impact speeds, both in the presence and absence of wall effects.

  9. Formation of dislocations, precipitates and cavities in He-implanted Mn-Cr austenitic steels

    Science.gov (United States)

    Ruedl, E.; Valdrè, G.

    1991-03-01

    Solution-annealed discs of three Mn-Cr austenitic steels containing different amounts of C and N were uniformly implanted at 310 K with 1000 appm He corresponding to ~ 0.2 dpa. The samples were subsequently aged at temperatures from 923 to 1073 K for various times and, after electropolishing, examined by TEM, EDS and EELS. A study was made of the dislocation loops developing on aging and of the compositional changes in their neighbourhood. The formation and growth of precipitates and He-filled cavities was also investigated together with the elemental segregation to the cavity surfaces. It was found that the microstructural evolution in the three materials can take various forms depending on many parameters.

  10. Source mechanisms of a collapsing solution mine cavity

    Science.gov (United States)

    Lennart Kinscher, Jannes; Cesca, Simone; Bernard, Pascal; Contrucci, Isabelle; Mangeney, Anne; Piguet, Jack Pierre; Bigarre, Pascal

    2016-04-01

    The development and collapse of a ~200 m wide salt solution mining cavity was seismically monitored in the Lorraine basin in northeastern France. Seismic monitoring and other geophysical in situ measurements were part of a large multi-parameter research project founded by the research "group for the impact and safety of underground works" (GISOS), whose database is being integrated in the EPOS platform (European Plate Observing System). The recorded microseismic events (~ 50,000 in total) show a swarm-like behaviour, with clustering sequences lasting from seconds to days, and distinct spatiotemporal migration. The majority of swarming signals are likely related to detachment and block breakage processes, occurring at the cavity roof. Body wave amplitude patterns indicate the presence of relatively stable source mechanisms, either associated with dip-slip and/or tensile faulting. However, short inter-event times, the high frequency geophone recordings, and the limited network station coverage often limits the application of classical source analysis techniques. In order to deal with these shortcomings, we examined the source mechanisms through different procedures including modelling of observed and synthetic waveforms and amplitude spectra of some well located events, as well as modelling of peak-to-peak amplitude ratios for most of the detected events. The latter approach was used to infer the average source mechanism of many swarming events at once by using a single three component station. To our knowledge this approach is applied here for the first time and represents an useful tool for source studies of seismic swarms and seismicity clusters. The results of the different methods are consistent and show that at least 50 % of the microseismic events have remarkably stable source mechanisms, associated with similarly oriented thrust faults, striking NW-SE and dipping around 35-55°. Consistent source mechanisms are probably related to the presence of a

  11. Solute-solvent cavity and bridge functions. I. Varying size of the solute

    International Nuclear Information System (INIS)

    In this work we present the results of the extensive molecular simulations of solute-solvent cavity and bridge functions. The mixtures of Lennard-Jones solvent with Lennard-Jones solute at infinite dilution are considered for different solute-solvent size ratios—up to 4:1. The Percus-Yevick and hypernetted chain closures deviate substantially from simulation results in the investigated temperature and density ranges. We also find that the behavior of the indirect and cavity correlation functions is non-monotonous within the hard-core region, but the latter can be successfully approximated by mean-field theory if the solute-solvent interaction energy is divided into repulsive and attractive contribution, according to Weeks-Chandler-Andersen theory. Furthermore, in spite of the non-monotonous behavior of logarithm of the cavity function and the indirect correlation function, their difference, i.e., the bridge function remains constant within the hard-core region. Such behavior of the bridge and indirect correlation functions at small distances and for small values of indirect correlation function is well known from the Duh-Haymet plots, where the non-unique relationship results in loops of the bridge function vs. indirect correlation function graphs. We show that the same pathological behavior appears also when distance is small and indirect correlation function is large. We further show that the unique functional behavior of the bridge function can be established when bridge is represented as a function of the renormalized, repulsive indirect correlation function

  12. Soliton-dark pulse pair formation in birefringent cavity fiber lasers through cross phase coupling.

    Science.gov (United States)

    Shao, Guodong; Song, Yufeng; Zhao, Luming; Shen, Deyuan; Tang, Dingyuan

    2015-10-01

    We report on the experimental observation of soliton-dark pulse pair formation in a birefringent cavity fiber laser. Temporal cavity solitons are formed in one polarization mode of the cavity. It is observed that associated with each of the cavity solitons a dark pulse is induced on the CW background of the orthogonal polarization mode. We show that the dark pulse formation is a result of the incoherent cross polarization coupling between the soliton and the CW beam and has a mechanism similar to that of the polarization domain formation observed in the fiber lasers. PMID:26480138

  13. Structural analysis of salt cavities formed by solution mining: I. Method of analysis and preliminary results for spherical cavities

    International Nuclear Information System (INIS)

    The primary objective of this effort is an analysis of the structural stability of cavities formed by solution mining in salt domes. In particular, the effects of depth (i.e. initial state of in situ stress), shape, volume (i.e. physical dimensions of the cavity), and sequence of salt excavation/fluid evacuation on the timewise structural stability of a cavity are of interest. It is anticipated that an assessment can be made of the interrelation between depth, cavern size, and cavern shape or of the practical limits therewith. In general, the cavity shape is assumed to be axisymmetric and the salt is assumed to exhibit nonlinear creep behavior. The primary emphasis is placed on the methodology of the finite element analysis, and the results of preliminary calculations for a spherically shaped cavity. It is common practice for engineers to apply elasticity theory to the behavior of rock in order to obtain near field stresses and displacements around an underground excavation in an effort to assess structural stability. Rock masses, particularly at depth, may be subjected to a rather complex state of initial stress, and may be nonhomogeneous and anisotropic. If one also includes complex geometrical excavation shape, the use of analytical techniques as an analysis tool is practically impossible. Thus, it is almost a necessity that approximate solution techniques be employed. In this regard, the finite element method is ideal as it can handle complex geometries and nonlinear material behavior with relative ease. An unusual feature of the present study is the incorporation into the finite element code of a procedure for handling the gradual creation or excavation of an underground cavity. During the excavation sequence, the salt is permitted to exhibit nonlinear stress-strain-time dependence. The bulk of this report will be devoted to a description of the analysis procedures, together with a preliminary calculation for a spherically shaped cavity

  14. Progress towards crab cavity solutions for the ILC

    Energy Technology Data Exchange (ETDEWEB)

    Burt, G.; Dexter, A.; /Lancaster U.; Bellantoni, L.; /Fermilab; Beard, C.; Goudket, P.; /Cockcroft Inst. Accel. Sci. Tech.

    2006-06-01

    In order to achieve acceptable luminosity for ILC crossing angles greater than 2 mrad, RF deflection cavities must be used to rotate electron and position bunches leading up to the IP. A bunch that passes through a deflection cavity at a phase where the deflection averages to zero, receives a crab kick leading to a finite rotation at the IP. For a beam energy of 500 GeV and a crossing angle of 20 mrad the required crab kick is about 11.4 MV at 1.3 GHz and 3.8 MV at 3.9 GHz. Cavities are needed on both beams and are likely to be positioned about 12 m before the IP. Any RF phase error between the bunch and the cavity leads to a deflection of the bunch in addition to a rotation of the bunch. Any differential phase error between the cavities leads to differing deflections and consequential loss in luminosity. An updated analysis of system requirements and phase tolerances with respect to original calculations [1] is given. Issues on cavity and frequency choice are discussed.

  15. Cavities

    Science.gov (United States)

    ... the bacteria produce acids that cause decay. Tooth pain occurs after decay reaches the inside of the tooth. Dentists can detect cavities by examining the teeth and taking x-rays periodically. Good oral hygiene and regular dental care plus a healthy diet can help prevent cavities. ...

  16. Analytical solutions for finite cylindrical dynamic cavity expansion in compressible elastic-plastic materials

    Institute of Scientific and Technical Information of China (English)

    甄明; 蒋志刚; 宋殿义; 刘飞

    2014-01-01

    Analytical solutions for the dynamic cylindrical cavity expansion in a com-pressible elastic-plastic cylinder with a finite radius are developed by taking into account of the effect of lateral free boundary, which are different from the traditional cavity expan-sion models for targets with infinite dimensions. The finite cylindrical cavity expansion process begins with an elastic-plastic stage followed by a plastic stage. The elastic-plastic stage ends and the plastic stage starts when the plastic wave front reaches the lateral free boundary. Approximate solutions of radial stress on cavity wall are derived by using the Von-Mise yield criterion and Forrestal’s similarity transformation method. The effects of the lateral free boundary and finite radius on the radial stress on the cavity wall are discussed, and comparisons are also conducted with the finite cylindrical cavity expansion in incompressible elastic-plastic materials. Numerical results show that the lateral free boundary has significant influence on the cavity expansion process and the radial stress on the cavity wall of metal cylinder with a finite radius.

  17. Precipitation and cavity formation in austenitic stainless steels during irradiation

    International Nuclear Information System (INIS)

    Microstructural evolution in austenitic stainless steels subjected to displacement damage at high temperature is strongly influenced by the interactions between helium atoms and second phase particles. Cavity nucleation occurs by the trapping of helium at partially coherent particle-matrix interfaces. The recent precipitate point defect collector theory describes the more rapid growth of precipitate-attached cavities compared to matrix cavities where the precipitate-matrix interface collects point defects to augment the normal point deflect flux to the cavitry. Data are presented which support these ideas. It is shown that during nickel ion irradiation of a titanium-modified stainless steel at 6750C the rate of injection of helium has a strong effect on the total swelling and also on the nature and distribution of precipitate phases

  18. Comparing the antibacterial activity of gaseous ozone and chlorhexidine solution on a tooth cavity model

    Science.gov (United States)

    Öztaş, Nurhan; Sümer, Zeynep

    2013-01-01

    Objective: To evaluate the antibacterial activity of gaseous ozone and chlorhexidine solution on a tooth cavity model. Study Design: Twenty-one human molars were divided into 3 groups. Cavities were then cut into the teeth (4 per tooth, 28 cavities per group). After sterilization, the teeth were left in broth cultures of 106 colony-forming units (CFU) ml-1 of Streptococcus mutans (S. mutans) at 36°C for 48 h. The appropriate treatment followed (group A, control; group B, 2% chlorhexidine solution; and group C, 80s of treatment with ozone, and the cavities were then filled with composite resin. After 72h, the restorations were removed, dentin chips were collected with an excavator, and the total number of microorganisms was determined. Results: Both of the treatments significantly reduced the number of S. mutans present compared with the control group and there was a significant difference between the all groups in terms of the amount of the microorganisms grown (p ozone group (p ozone application could be an anlternative cavity disinfection method because of ozone’s cavity disinfection activity. Key words:Antibacterial activity, chlorhexidine, ozone, streptococcus mutans, tooth cavity. PMID:24455068

  19. Open Cavity Solutions to the rf in Magnetic Field Problem

    CERN Document Server

    Palmer, R; Fernow, R; Gallardo, J C; Kirk, H

    2008-01-01

    It has been observed \\cite{break} that breakdown in an 805 MHz pill-box cavi ty occurs at much lower gradients as an external axial magnetic field is inc reased. This effect was not observed with on open iris cavity. It is propose d that this effect depends on the relative angles of the magnetic and maximu m electric fields: parallel in the pill-box case; at an angle in the open ir is case. If so, using an open iris structure with solenoid coils in the iris es should perform even better. A lattice, using this principle, is presented, for use in 6D cooling for a Muon Collider. Experimental layouts to test th is principle are proposed.

  20. Monitoring the formation of oxide apertures in micropillar cavities

    CERN Document Server

    Bakker, Morten P; Suntrup, Donald J; Truong, Tuan-Ahn; van Exter, Martin P; Bouwmeester, Dirk

    2013-01-01

    We present an imaging technique that enables us to monitor the wet thermal oxidation of a thin AlAs layer embedded between two distributed Bragg reflector (DBR) mirrors in a micropillar. Directly after oxidation, we confirm in situ, without any further fabrication steps, that high quality optical modes confined to a small volume are formed. The combination of these two optical techniques provides a reliable and efficient way of producing oxidation apertured micropillar cavities for which the wet thermal oxidation is a critical fabrication step.

  1. Prediction and prevention of adhesion formation of the abdominal cavity

    OpenAIRE

    Alisher, Zh; Zhandos, T.; Nurbolat, E.; Zarina, R.; Dinara, Shaki

    2015-01-01

    BACKGROUND The existence of adhesive disease was known in the middle of the XIX century, N.N. Blinov in the middle of the XX century in his monograph “Adhesive disease”, wrote that post-surgical adhesions in the abdominal cavity – is a defect of surgeon. At present time, it is known that adhesive disease is the adhesions of connective tissue between adjacent organs or the peritoneal surface resulting from damage of their walls (more often during a surgical intervention). As of today, there ar...

  2. Formation and growth of nanocavities and cavities induced by He+ implantation in silicon

    Science.gov (United States)

    Nguyen, My Anh; Ruault, Marie-Odile; Fortuna, Franck

    2012-03-01

    Nanocavities and cavities are known to be efficient gettering sites for metallic impurities in silicon. Here, we report results from implanted lang100rang silicon at room temperature with 50 keV helium ions at a dose of 3×1016 cm‑2. Due to its low solubility, He segregates in gas-vacancy complexes and forms nanobubbles. Then, during an N2 ambient annealing at 800 °C using either rapid thermal annealing (RTA) or conventional furnace annealing, nanobubbles grow and He is released from the nanobubbles by gas exodiffusion, leading to (nano)cavities' formation. (Nano)cavities and residual defects were observed by transmission electron microscopy (TEM). The fraction of retained helium was shown to decrease with annealing time according to the first-order gas release model. Two nucleation-growth mechanisms involved in the growth of these (nano)cavities have been studied. A remarkable result shows evidence about the balance-time dependence of the two mechanisms involved in the growth process of (nano)cavities. At the very beginning (30 s) of the annealing, the main mechanism is the migration-coalescence including nanobubbles and vacancy-helium complexes leading to the cavities' formation. Then, the Ostwald ripening mechanism, related to the helium exodiffusion, between the nanocavities and cavities appeared.

  3. Solution of the Navier-Stokes equations for a driven cavity

    Science.gov (United States)

    Semeraro, B. D.; Sameh, Ahmed

    1991-03-01

    The flow field in a lid driven cavity is determined by integration of the incompressible Navier-Stokes equations. The numerical integration is accomplished via an operator splitting method known as the theta-scheme. This splitting separates the problem into the solution of a quasi-stokes problem and a nonlinear convection problem. Some details of solution methods used for the two subproblems and results obtained for the driven cavity are described. The schemes developed for the quasi-Stokes problem are more advanced at this stage than those for the nonlinear problem. However, the approaches used for both parts are outlined. As a model problem, a two dimensional square cavity with sides of unit length and a lid moving with unit velocity from left to right is considered. The Navier-Stokes equations are discretized in space on a uniform staggered or MAC mesh. The time discretization is accomplished via the theta-scheme.

  4. Weighted-density functionals for cavity formation and dispersion energies in continuum solvation models

    Energy Technology Data Exchange (ETDEWEB)

    Sundararaman, Ravishankar; Gunceler, Deniz; Arias, T. A. [Department of Physics, Cornell University, Ithaca, New York 14853 (United States)

    2014-10-07

    Continuum solvation models enable efficient first principles calculations of chemical reactions in solution, but require extensive parametrization and fitting for each solvent and class of solute systems. Here, we examine the assumptions of continuum solvation models in detail and replace empirical terms with physical models in order to construct a minimally-empirical solvation model. Specifically, we derive solvent radii from the nonlocal dielectric response of the solvent from ab initio calculations, construct a closed-form and parameter-free weighted-density approximation for the free energy of the cavity formation, and employ a pair-potential approximation for the dispersion energy. We show that the resulting model with a single solvent-independent parameter: the electron density threshold (n{sub c}), and a single solvent-dependent parameter: the dispersion scale factor (s{sub 6}), reproduces solvation energies of organic molecules in water, chloroform, and carbon tetrachloride with RMS errors of 1.1, 0.6 and 0.5 kcal/mol, respectively. We additionally show that fitting the solvent-dependent s{sub 6} parameter to the solvation energy of a single non-polar molecule does not substantially increase these errors. Parametrization of this model for other solvents, therefore, requires minimal effort and is possible without extensive databases of experimental solvation free energies.

  5. Effect of H and He irradiation on cavity formation and blistering in ceramics

    International Nuclear Information System (INIS)

    Single- or poly-crystalline specimens of SiC, Si3N4, MgO, Al2O3 and MgAl2O4 were implanted with 0.4–1 MeV H+ or He+ ion beams at room temperature and 650 °C up to fluences of ∼1 × 1022/m2. This produced peak implanted gas and displacement damage levels as high as ∼50 at.% and 34 displacements per atom (dpa). The specimens were subsequently examined optically, and in cross-section using transmission electron microscopy. Subsurface blistering occurred for specimens irradiated to H or He fluences greater than about 3 × 1021/m2 (∼15 at.% peak implanted gas concentration), and surface exfoliation occurred for fluences above ∼1 × 1022/m2 (∼40 at.% implanted gas). Both helium and hydrogen had comparable effectiveness for inducing blistering and exfoliation on an atomic basis. The threshold blistering and exfoliation fluences for both ions were weakly dependent on temperature between 25 and 650 °C. Both H and He were found to be very effective in inducing matrix cavity formation, due to their low solubility in these ceramics. The implanted gas concentrations that resulted in visible cavity formation generally ranged from 1 to 5 at.%. Visible cavity formation was readily induced during room temperature irradiation despite the limited vacancy mobility in these ceramics at room temperature. Three general types of cavity morphologies were observed: isolated cavities, clusters of small cavities (typically associated with dislocation loops), and two-dimensional platelets. Cavity formation was observed to initiate at the periphery of dislocation loops in some cases. During elevated temperature irradiation, cavity formation was often observed to be preferentially associated with certain low-index habit planes, particularly if the habit plane was oriented nearly parallel to the irradiated surface: (0 0 0 1) and {11¯00} for Al2O3, (0 0 0 1) for α–SiC, {0 0 1} and {1 1 0} for MgO, and {1 1 0} and {1 1 1} for MgAl2O4. The bubble formation and blistering behavior

  6. Effect of H and He Irradiation on Cavity Formation and Blistering in Ceramics

    International Nuclear Information System (INIS)

    Single- or poly-crystalline specimens of SiC, Si3N4, MgO, Al2O3 and MgAl2O4 were implanted with 0.4-1 MeV H+ or He+ ion beams at room temperature and 650 C up to fluences of ∼1 x 1022/m2. This produced peak implanted gas and displacement damage levels as high as ∼50 at.% and 34 displacements per atom (dpa). The specimens were subsequently examined optically, and in cross-section using transmission electron microscopy. Subsurface blistering occurred for specimens irradiated to H or He fluences greater than about 3 x 1021/m2 (∼15 at.% peak implanted gas concentration), and surface exfoliation occurred for fluences above ∼1 x 1022/m2 (∼40 at.% implanted gas). Both helium and hydrogen had comparable effectiveness for inducing blistering and exfoliation on an atomic basis. The threshold blistering and exfoliation fluences for both ions were weakly dependent on temperature between 25 and 650 C. Both H and He were found to be very effective in inducing matrix cavity formation, due to their low solubility in these ceramics. The implanted gas concentrations that resulted in visible cavity formation generally ranged from 1 to 5 at.%. Visible cavity formation was readily induced during room temperature irradiation despite the limited vacancy mobility in these ceramics at room temperature. Three general types of cavity morphologies were observed: isolated cavities, clusters of small cavities (typically associated with dislocation loops), and two-dimensional platelets. Cavity formation was observed to initiate at the periphery of dislocation loops in some cases. During elevated temperature irradiation, cavity formation was often observed to be preferentially associated with certain low-index habit planes, particularly if the habit plane was oriented nearly parallel to the irradiated surface: (0001) and {1(bar 1)00} for Al2O3, (0001) for a-SiC, {001} and {110} for MgO, and {110} and {111} for MgAl2O4. The bubble formation and blistering behavior of the ceramics was

  7. Contact nuclei formation in aqueous dextrose solutions

    Science.gov (United States)

    Cerreta, Michael K.; Berglund, Kris A.

    1990-06-01

    A laser Raman microprobe was used in situ to observe the growth of alpha dextrose monohydrate on alpha anhydrous dextrose crystals. The Raman spectra indicate growth of the monohydrate below 28.1°C, but the presence of only the anhydrous form above 40.5°C. Contact nucleation experiments with parent anhydrous crystals yielded only monohydrate nuclei below 28.1°C, while contacts in solutions between 34.5 and 41.0°C produced both crystalline forms, and contacts in solutions above 43.5°C produced only anhydrous nuclei. The inability of the monohydrate to grow on anhydrous crystals in the same solution that forms the two crystalline phases with a single contact precludes a simple attrition mechanism of nuclei formation. For the same reason, the hypothetical mechanism involving parent crystal stabilization of pre-crystalline clusters, allowing the clusters to grow into nuclei, is also contradicted. A third, mechanism, which may be a combination of the two, is believed to apply.

  8. SDO/AIA DETECTION OF SOLAR PROMINENCE FORMATION WITHIN A CORONAL CAVITY

    Energy Technology Data Exchange (ETDEWEB)

    Berger, Thomas E. [National Solar Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Liu Wei [Lockheed Martin Solar and Astrophysics Laboratory, B/252 3251 Hanover Street, Palo Alto, CA 94304 (United States); Low, B. C. [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307 (United States)

    2012-10-20

    We report the first analyses of SDO/AIA observations of the formation of a quiescent polar crown prominence in a coronal cavity. The He II 304 A (log T{sub max} {approx} 4.8 K) data show both the gradual disappearance of the prominence due to vertical drainage and lateral transport of plasma followed by the formation of a new prominence 12 hr later. The formation is preceded by the appearance of a bright emission 'cloud' in the central region of the coronal cavity. The peak brightness of the cloud progressively shifts in time from the Fe XIV 211 A channel, through the Fe XII 193 A channel, to the Fe IX 171 A channel (log T{sub max} {approx} 6.2, 6.1, 5.8 K, respectively) while simultaneously decreasing in altitude. Filter ratio analysis estimates the initial temperature of the cloud to be approximately log T {approx} 6.25 K with evidence of cooling over time. The subsequent growth of the prominence is accompanied by darkening of the cavity in the 211 A channel. The observations imply prominence formation via in situ condensation of hot plasma from the coronal cavity, in support of our previously proposed process of magnetothermal convection in coronal magnetic flux ropes.

  9. Transverse Mode Structure and Pattern Formation in Oxide Confined Vertical Cavity Semiconductor Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Choquette, K.D.; Geib, K.M.; Hegarty, S.P.; Hou, H.Q.; Huyet, G.; McInerney, J.G.; Porta, P.

    1999-07-06

    We analyze the transverse profiles of oxide-confined vertical cavity laser diodes as a function of aperture size. For small apertures we demonstrate that thermal lensing can be the dominant effect in determining the transverse resonator properties. We also analyze pattern formation in lasers with large apertures where we observe the appearance of tilted waves.

  10. Numerical model for the solution of two-dimensional natural convection problems in arbitrary cavities

    International Nuclear Information System (INIS)

    In this research work a numerical model for the solution of two-dimensional natural convection problems in arbitrary cavities of a Boussinesq fluid is presented. The conservation equations are written in a general curvilinear coordinate system which matches the irregular boundaries of the domain. The nonorthogonal system is generated by a suitable system of elliptic equations. The momentum and continuity equations are transformed from the Cartesian system to the general curvilinear system keeping the Cartesian velocity components as the dependent variables in the transformed domain. Finite difference equations are obtained for the contravariant velocity components in the transformed domain. The numerical calculations are performed in a fixed rectangular domain and both the Cartesian and the contravariant velocity components take part in the solutiomn procedure. The dependent variables are arranged on the grid in a staggered manner. The numerical model is tested by solving the driven flow in a square cavity with a moving side using a nonorthogoanl grid. The natural convenction in a square cavity, using an orthogonal and a nonorthogonal grid, is also solved for the model test. Also, the solution for the buoyancy flow between a square cylinder placed inside a circular cylinder is presented. The results of the test problems are compared with those available in the specialized literature. Finally, in order to show the generality of the model, the natural convection problem inside a very irregular cavity is presented. (Author)

  11. Integral transform solution for natural convection in three-dimensional porous cavities: Aspect ratio effects

    Energy Technology Data Exchange (ETDEWEB)

    Luz Neto, H. [National Institute of Technology, INT/MCT Ministerio de Ciencia e Tecnologia, Rio de Janeiro, RJ (Brazil); Quaresma, J.N.N. [Chemical and Food Engineering Department, DEQAL/UFPA, Universidade Federal do Para Belem, PA (Brazil); Cotta, R.M. [Mechanical Engineering Department, POLI/COPPE/UFRJ, Cidade Universitaria, Federal University of Rio de Janeiro, Cx. Postal 68503, 21945-970 Rio de Janeiro, RJ (Brazil)

    2006-11-15

    Three-dimensional natural convection in box-like cavities filled with a porous material is revisited, by considering a transient formulation for the energy balance and a quasi-steady formulation for the flow problem. The Generalized Integral Transform Technique (GITT) is employed in the hybrid numerical-analytical solution of the Darcy law based model for vertical cavities (insulated vertical walls with differentially prescribed horizontal wall temperatures), employing the vorticity-vector potential formulation. Comparisons with previously reported numerical solutions are performed and the transition between conductive and convective states is illustrated, centering on the aspect ratio influence on the flow and heat transfer phenomena. A set of reference results for the steady-state behavior under different aspect ratio is provided for covalidation purposes. (author)

  12. DYNAMICAL FORMATION OF CAVITY FOR COMPOSED THERMAL HYPERELASTIC SPHERES IN NON-UNIFORM TEMPERATURE FIELDS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Dynamical formation and growth of cavity in a sphere composed of two incompressible thermal-hyperelastic Gent-Thomas materials were discussed under the case of a non-uniform temperature field and the surface dead loading. The mathematical model was first presented based on the dynamical theory of finite deformations. An exact differential relation between the void radius and surface load was obtained by using the variable transformation method. By numerical computation, critical loads and cavitation growth curves were obtained for different temperatures. The influence of the temperature and material parameters of the composed sphere on the void formation and growth was considered and compared with those for static analysis. The results show that the cavity occurs suddenly with a finite radius and its evolvement with time displays a non-linear periodic vibration and that the critical load decreases with the increase of temperature and also the dynamical critical load is lower than the static critical load under the same conditions.

  13. Environmental Chamber Study of Atmospheric Chemistry and Secondary Organic Aerosol Formation Using Cavity Enhanced Absorption Spectroscopy

    OpenAIRE

    Liu, Yingdi

    2011-01-01

    Air pollution and global climate change are important environmental issues that affect our society. Deeper understanding of atmospheric chemistry is required to understand these problems and to develop effective control strategies. Environmental chambers have been used for the past few decades to study atmospheric chemistry and investigate processes leading to secondary pollutant formation. This thesis work provides two different high sensitivity real time cavity enhance absorption spectrosco...

  14. On the formation of noise-like pulses in fiber ring cavity configurations

    Science.gov (United States)

    Jeong, Yoonchan; Vazquez-Zuniga, Luis Alonso; Lee, Seungjong; Kwon, Youngchul

    2014-12-01

    We give an overview of the current status of fiber-based noise-like pulse (NLP) research conducted over the past decade, together with presenting the newly conducted, systematic study on their temporal, spectral, and coherence characteristics in nonlinear polarization rotation (NPR)-based erbium-doped fiber ring cavity configurations. Firstly, our study includes experimental investigations on the characteristic features of NLPs both in the net anomalous dispersion regime and in the net normal dispersion regime, in comparison with coherent optical pulses that can alternatively be obtained from the same cavity configurations, i.e., with the conventional and dissipative solitons. Secondly, our study includes numerical simulations on the formation of NLPs, utilizing a simplified, scalar-field model based on the characteristic transfer function of the NPR mechanism in conjunction with the split-step Fourier algorithm, which offer a great help in exploring the interrelationship between the NLP formation and various cavity parameters, and eventually present good agreement with the experimental results. We stress that if the cavity operates with excessively high gain, i.e., higher than the levels just required for generating coherent mode-locked pulses, i.e., conventional solitons and dissipative solitons, it may trigger NLPs, depending on the characteristic transfer function of the NPR mechanism induced in the cavity. In particular, the NPR transfer function is characterized by the critical saturation power and the linear loss ratio. Finally, we also report on the applications of the fiber-based NLP sources, including supercontinuum generation in a master-oscillator power amplifier configuration seeded by a fiber-based NLP source, as one typical example. We expect that the NLP-related research area will continue to expand, and that NLP-based sources will also find more applications in the future.

  15. Integral transform solution of natural convection in a square cavity with volumetric heat generation

    Directory of Open Access Journals (Sweden)

    C. An

    2013-12-01

    Full Text Available The generalized integral transform technique (GITT is employed to obtain a hybrid numerical-analytical solution of natural convection in a cavity with volumetric heat generation. The hybrid nature of this approach allows for the establishment of benchmark results in the solution of non-linear partial differential equation systems, including the coupled set of heat and fluid flow equations that govern the steady natural convection problem under consideration. Through performing the GITT, the resulting transformed ODE system is then numerically solved by making use of the subroutine DBVPFD from the IMSL Library. Therefore, numerical results under user prescribed accuracy are obtained for different values of Rayleigh numbers, and the convergence behavior of the proposed eigenfunction expansions is illustrated. Critical comparisons against solutions produced by ANSYS CFX 12.0 are then conducted, which demonstrate excellent agreement. Several sets of reference results for natural convection with volumetric heat generation in a bi-dimensional square cavity are also provided for future verification of numerical results obtained by other researchers.

  16. SDO/AIA Detection of Solar Prominence Formation within a Coronal Cavity

    CERN Document Server

    Berger, Thomas E; Low, B C

    2012-01-01

    We report the first analyses of SDO/AIA observations of the formation of a quiescent polar crown prominence in a coronal cavity. The He II 304 \\AA (log T_{max} \\sim 4.8 K) data show both the gradual disappearance of the prominence due to vertical drainage and lateral transport of plasma followed by its reappearance some 12 hours later. The reformation of the prominence is preceded by the appearance of a bright emission "cloud" in the central region of the coronal cavity. The peak brightness of the cloud progressively shifts in time from the Fe XIV 211 \\AA channel, through the Fe XII 193 \\AA channel, to the Fe IX 171 \\AA channel (log T_{max} \\sim 6.2, 6.1, 5.8 K, respectively) while simultaneously decreasing in altitude. Filter ratio analysis estimates the initial temperature of the cloud in the cavity to be approximately log T \\sim 6.25 K with evidence of cooling over time. The subsequent growth of the prominence is accompanied by darkening of the cavity in the 211 \\AA channel. The observations imply the poss...

  17. First-principles calculations of niobium hydride formation in superconducting radio-frequency cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Denise C.; Cooley, Lance D.; Seidman, David N.

    2013-09-01

    Niobium hydride is suspected to be a major contributor to degradation of the quality factor of niobium superconducting radio-frequency (SRF) cavities. In this study, we connect the fundamental properties of hydrogen in niobium to SRF cavity performance and processing. We modeled several of the niobium hydride phases relevant to SRF cavities and present their thermodynamic, electronic, and geometric properties determined from calculations based on density-functional theory. We find that the absorption of hydrogen from the gas phase into niobium is exothermic and hydrogen becomes somewhat anionic. The absorption of hydrogen by niobium lattice vacancies is strongly preferred over absorption into interstitial sites. A single vacancy can accommodate six hydrogen atoms in the symmetrically equivalent lowest-energy sites and additional hydrogen in the nearby interstitial sites affected by the strain field: this indicates that a vacancy can serve as a nucleation center for hydride phase formation. Small hydride precipitates may then occur near lattice vacancies upon cooling. Vacancy clusters and extended defects should also be enriched in hydrogen, potentially resulting in extended hydride phase regions upon cooling. We also assess the phase changes in the niobium-hydrogen system based on charge transfer between niobium and hydrogen, the strain field associated with interstitial hydrogen, and the geometry of the hydride phases. The results of this study stress the importance of not only the hydrogen content in niobium, but also the recovery state of niobium for the performance of SRF cavities.

  18. Reversible cluster formation in concentrated monoclonal antibody solutions

    Science.gov (United States)

    Godfrin, P. Douglas; Porcar, Lionel; Falus, Peter; Zarraga, Isidro; Wagner, Norm; Liu, Yun

    2015-03-01

    Protein cluster formation in solution is of fundamental interest for both academic research and industrial applications. Recently, industrial scientists are also exploring the effect of reversible cluster formation on biopharmaceutical processing and delivery. However, despite of its importance, the understanding of protein clusters at concentrated solutions remains scientifically very challenging. Using the neutron spin echo technique to study the short time dynamics of proteins in solutions, we have recently systematically studied cluster formation in a few monoclonal antibody (mAb) solutions and their relation with solution viscosity. We show that the existence of anisotropic attraction can cause the formation of finite sized clusters, which increases the solution viscosity. Interestingly, once clusters form at relatively low concentrations, the average size of clusters in solutions remains almost constant over a wide range of concentrations similar to that of micelle formation. For a different mAb we have also investigated, the attraction is mostly induced by hydrophobic patches. As a result, these mAbs form large clusters with loosely linked proteins. In both cases, the formation of clusters all increases the solution viscosity substantially. However, due to different physics origins of cluster formation, solutions viscosities for these two different types of mAbs need to be controlled by different ways.

  19. Kinetic characteristics of crystallization from model solutions of the oral cavity

    Science.gov (United States)

    Golovanova, O. A.; Chikanova, E. S.

    2015-11-01

    The kinetic regularities of crystallization from model solutions of the oral cavity are investigated and the growth order and constants are determined for two systems: saliva and dental plaque fluid (DPF). It is found that the stage in which the number of particles increases occurs in the range of mixed kinetics and their growth occurs in the diffusion range. The enhancing effect of additives HCO- 3 > C6H12O6 > F- and the retarding effect of Mg2+ are demonstrated. The HCO- 3 and Mg2+ additives, taken in high concentrations, affect the corresponding rate constants. It is revealed the crystallization in DPF is favorable for the growth of small crystallites, while the model solution of saliva is, vice versa, favorable for the growth of larger crystals.

  20. Cosmological long-wavelength solutions and primordial black hole formation

    CERN Document Server

    Harada, Tomohiro; Nakama, Tomohiro; Koga, Yasutaka

    2015-01-01

    We construct cosmological long-wavelength solutions without symmetry in general gauge conditions compatible with the long-wavelength scheme. We then specify the relationship among the solutions in different time slicings. Nonspherical long-wavelength solutions are particularly important for primordial structure formation in the epoch of soft equations of state. Applying this framework to spherical symmetry, we show the equivalence between long-wavelength solutions in the constant mean curvature slicing and asymptotic quasi-homogeneous solutions in the comoving slicing. We derive the correspondence relation and compare the results of numerical simulations of primordial black hole (PBH) formation. In terms of $\\tilde{\\delta}_{c}$, the value which the averaged density perturbation at threshold in the comoving slicing would take at horizon entry in the first-order long-wavelength expansion, we find that the sharper the transition from the overdense region to the FRW universe is, the larger the $\\tilde{\\delta}_{c}...

  1. Complex formation of CdSe/ZnS/TOPO nanocrystal vs. molecular chaperone in aqueous solution by hydrophobic interaction

    International Nuclear Information System (INIS)

    Feasibilities to stabilize CdSe/ZnS/trioctylphosphineoxide (TOPO) nanocrystals (quantum dots, QDs) in aqueous solutions with prefoldin macromolecules in their bioactive states are reported. Prefoldin is a jellyfish-shaped hexameric co-chaperone of the group II chaperonins. As a protein folding intermediate is captured within its central cavity, so CdSe/ZnS/TOPO QDs would also be included within this cavity. It is also found the QDs can be much more dispersed in aqueous solutions and suspended for certain period of time by adding trace amount of t-butanol in the buffer prior to the mixing of the QDs mother solution. While biochemical procedures are evaluated with ordinary fluorescence measurements, possible complex formations are also evaluated with TIRFM single-molecule detection techniques

  2. Reactivity effects of void formations in a solution critical assembly

    Energy Technology Data Exchange (ETDEWEB)

    Walters, S.G.

    1994-01-01

    SHEBA II (Solution High Energy Burst Assembly) was constructed in order to better understand the neutronics of solutions of fissile materials. In order to estimate the effect on criticality from the formation of bubbles, models were devised in MCNP (Monte Carlo Neutron Photon transport code) and THREEDANT (THREE dimensional, Diffusion-Accelerated, Neutral-Particle Transport). It was found that the formation of voids in all but the outside bottom edge of the assembly cylinder tend to act as a negative insertion of reactivity. Also, an experiment has been designed which will verify the results of the codes.

  3. A Comprehensive study of Cavities on the Sun: Structure, Formation, and Evolution

    Science.gov (United States)

    Karna, Nishu; Zhang, Jie; Pesnell, William D.

    2016-05-01

    Coronal cavities are large-scale structures in the Sun's corona that are closely related with the long-term evolution of the magnetic field in the photosphere as well as associated with the energetic solar activity such as prominence eruptions and coronal mass ejections. They are observed as circular or elliptical-shaped relatively low-density dark regions above the solar limb in EUV, X-ray, and white-light coronal images. We used SDO/AIA limb synoptic maps, constructed from annuli above the solar limb, to systematically identify cavities. We observed 429 coronal prominence cavities between May 20, 2010 and Feb 1, 2015. We examined correlations between height, width, and length of the cavities. Based on the fitting of the shape of the cross section, we classified cavities in three types: prolate (38%), oblate (27%) and circular (35%). We found that the cavities of all shapes are common in shorter length while circular and oblate cavities are more common in the longer length. In general, we found that the overall 3-D topology of long stable cavities can be characterized as a long tube with an elliptical cross-section. Next, we investigated the pattern of cavity location and found that cavity systematically drifts towards the pole. We found that cavities form a belt by making a plot using SDO/HMI surface magnetogram similar to classical buttery diagram of sunspots, we call that the cavity belt. Our analysis showed that the cavity belts migrated towards higher latitude with time and the cavity belts disappeared after the polar magnetic field reversal. This result shows that cavity evolution provides new insight into the solar cycle. Moreover, we studied the underlying magnetic field of a circumpolar crown cavity (Mar 21, 2013- Oct 25, 2013) that was observed for several Carrington Rotations. Our results showed that the underlying polarity inversion line of cavities is formed between the trailing part of decayed active regions and the unipolar magnetic field in the

  4. Transport of reactive solutes in heterogeneous porous formation.

    NARCIS (Netherlands)

    Bosma, W.J.P.

    1994-01-01

    Transport and spreading behaviour of reactive solutes in heterogeneous porous formations is considered. Spatial variability is modeled by assuming a random space function (RSF) for the spatially variable properties. In the available literature, the effect of random spatial variability is mostly limi

  5. Structure formation in solution ionic polymers and colloidal particles

    CERN Document Server

    Ise, Norio

    2005-01-01

    This book is designed to critically review experimental findings on ionic polymers and colloidal particles and to prove a theoretical framework based on the Poisson-Boltzmann approach. Structure formation in ionic polymer solutions has attracted attention since the days of H. Staudinger and J. D. Bernal. An independent study on ionic colloidal dispersions with microscopy provided a compelling evidence of structure formation. Recent technical developments have made it possible to accumulate relevant information for both ionic polymers and colloidal particles in dilute systems. The outstanding phenomenon experimentally found is microscopic inhomogeneity in the solute distribution in macroscopically homogeneous systems.To account for the observation, the present authors have invoked the existence of the counterion-mediated attraction between similarly charged solute species, in addition to the widely accepted electrostatic repulsion.

  6. Thermal effects on fluid flow and hydraulic fracturing from wellbores and cavities in low-permeability formations

    Energy Technology Data Exchange (ETDEWEB)

    Yarlong Wang [Petro-Geotech Inc., Calgary, AB (Canada); Papamichos, Euripides [IKU Petroleum Research, Trondheim (Norway)

    1999-07-01

    The coupled heat-fluid-stress problem of circular wellbore or spherical cavity subjected to a constant temperature change and a constant fluid flow rate is considered. Transient analytical solutions for temperature, pore pressure and stress are developed by coupling conductive heat transfer with Darcy fluid flow in a poroelastic medium. They are applicable to lower permeability porous media suitable for liquid-waste disposal and also simulating reservoir for enhanced oil recovery, where conduction dominates the heat transfer process. A full range of solutions is presented showing separately the effects of temperature and fluid flow on pore pressure and stress development. It is shown that injection of warm fluid can be used to restrict fracture development around wellbores and cavities and generally to optimise a fluid injection operation. Both the limitations of the solutions and the convective flow effect are addressed. (Author)

  7. Radiolytic gas formation in high-level liquid waste solutions

    International Nuclear Information System (INIS)

    High-level fission product waste solutions originating from the first-cycle raffinate stream of spent fast breeder reactor fuel reprocessing have been investigated gas chromatographically for their radiolytic and chemical gas production. The solutions showed considerable formation of hydrogen, carbon dioxide and dinitrogen oxide, whereas atmospheric oxygen was consumed completely within a short time. In particular, carbon dioxide resulted from the radiolytic degradation of entrained organic solvent. After nearly complete degradation of the organic solvent, the influence of hydrazine and nitrogen dioxide on hydrogen formation was investigated. Hydrazinium hydroxide led to the formation of dinitrogen oxide and nitrogen. After 60 d, the concentration of dinitrogen oxide had reduced to zero, whereas the amount of nitrogen formed had reached a maximum. This may be explained by simultaneous chemical and radiolytic reactions leading to the formation of dinitrogen oxide and nitrogen and photolytic fission of dinitrogen oxide. Addition of sodium nitrite resulted in the rapid formation of dinitrogen oxide. The rate of hydrogen production was not changed significantly after the addition of hydrazine or nitrite. The results indicate that under normal operating conditions no dangerous hydrogen radiolysis yields should develop in the course of reprocessing and high-level liquid waste tank storage. Organic entrainment may lead to enhanced radiolytic decomposition and thus to considerable hydrogen production rates and pressure build-up in closed systems. (author)

  8. Spherical harmonic series solution of fields excited by vertical electric dipole in earth-ionosphere cavity

    Institute of Scientific and Technical Information of China (English)

    Yuanxin WANG; Wensheng FAN; Weiyan PAN; Hongqi ZHANG

    2008-01-01

    The spherical harmonic series expression of electromagnetic fields excited by ELF/SLF vertical electric dipole in the spherical earth-ionosphere cavity is derived when the earth and ionosphere are regarded as non-ideal conductors. A method of speeding numerical convergence has been presented. The electromagnetic fields in the cavity are calculated by this algorithm, and the results show that the electromagnetic fields between the earth and the ionosphere are the sum of two traveling waves in the SLF band. Moreover, the results are in complete agreement with that of the well-known spherical second-order approximation in the SLF band. The electromagnetic fields in the cavity are a type of standing wave in the ELF band and the variation of the amplitude versus frequency coincides with Schumann's resonance.

  9. Stationary bubble formation and cavity collapse in wedge-shaped hoppers

    Science.gov (United States)

    Yagisawa, Yui; Then, Hui Zee; Okumura, Ko

    2016-01-01

    The hourglass is one of the apparatuses familiar to everyone, but reveals intriguing behaviors peculiar to granular materials, and many issues are remained to be explored. In this study, we examined the dynamics of falling sand in a special form of hourglass, i.e., a wedge-shaped hopper, when a suspended granular layer is stabilized to a certain degree. As a result, we found remarkably different dynamic regimes of bubbling and cavity. In the bubbling regime, bubbles of nearly equal size are created in the sand at a regular time interval. In the cavity regime, a cavity grows as sand beads fall before a sudden collapse of the cavity. Bubbling found here is quite visible to a level never discussed in the physics literature and the cavity regime is a novel phase, which is neither continuous, intermittent nor completely blocked phase. We elucidate the physical conditions necessary for the bubbling and cavity regimes and develop simple theories for the regimes to successfully explain the observed phenomena by considering the stability of a suspended granular layer and clogging of granular flow at the outlet of the hopper. The bubbling and cavity regimes could be useful for mixing a fluid with granular materials. PMID:27138747

  10. Stationary bubble formation and cavity collapse in wedge-shaped hoppers.

    Science.gov (United States)

    Yagisawa, Yui; Then, Hui Zee; Okumura, Ko

    2016-01-01

    The hourglass is one of the apparatuses familiar to everyone, but reveals intriguing behaviors peculiar to granular materials, and many issues are remained to be explored. In this study, we examined the dynamics of falling sand in a special form of hourglass, i.e., a wedge-shaped hopper, when a suspended granular layer is stabilized to a certain degree. As a result, we found remarkably different dynamic regimes of bubbling and cavity. In the bubbling regime, bubbles of nearly equal size are created in the sand at a regular time interval. In the cavity regime, a cavity grows as sand beads fall before a sudden collapse of the cavity. Bubbling found here is quite visible to a level never discussed in the physics literature and the cavity regime is a novel phase, which is neither continuous, intermittent nor completely blocked phase. We elucidate the physical conditions necessary for the bubbling and cavity regimes and develop simple theories for the regimes to successfully explain the observed phenomena by considering the stability of a suspended granular layer and clogging of granular flow at the outlet of the hopper. The bubbling and cavity regimes could be useful for mixing a fluid with granular materials. PMID:27138747

  11. Cavity Formation in Aluminium Irradiated with a Pulsating Beam of 225 MeV Electrons

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Bilde-Sørensen, Jørgen; Leffers, Torben;

    1984-01-01

    High-purity aluminium was irradiated with a pulsating beam of 225 MeV electrons to a maximum dose of 0.035 dpa with a helium generation rate of up to 17 appm/dpa. The irradiated samples contained cavities in the size range 5 to 70 nm. In a zone of up to 14 μm from the grain boundaries cavity size...

  12. Stationary bubble formation and cavity collapse in wedge-shaped hoppers

    CERN Document Server

    Yagisawa, Yui; Okumura, Ko

    2016-01-01

    The hourglass is one of the apparatuses familiar to everyone, but reveals intriguing behaviors peculiar to granular materials, and many issues are remained to be explored. In this study, we examined the dynamics of falling sand in a special form of hourglass, i.e., a wedge-shaped hopper, when a suspended granular layer is stabilized to a certain degree. As a result, we found remarkably different dynamics, bubbling and cavity regimes. In the bubbling regime, bubbles of nearly equal size are created in the sand at a regular time interval. In the cavity regime, a cavity grows as sand beads fall before a sudden collapse of the cavity. Bubbling found here is quite visible to a level never discussed in the physics literature and the cavity regime is a novel phase, which is neither continuous, intermittent nor completely blocked phase. We elucidate the physical conditions necessary for the bubbling and cavity regimes and develop simple theories for the regimes to successfully explain the observed phenomena by consid...

  13. Effects of A Top SiO2 Surface Layer on Cavity Formation and Helium Desorption in Silicon

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Cz n-type Si (100) samples with and without a top SiO2 layer were implanted with 40 keV helium ions at the same dose of 5×1016 cm-2. Cross-sectional transmission electron microscopy (XTEM) and thermal desorption spectroscopy (THDS) were used to study the thermal evolution of cavities upon and helium thermal release, respectively. XTEM results show that the presence of the top SiO2 layer could suppress the thermal growth of cavities mainly formed in the region close to the SiO2/Si interface, which leads to the reduction in both the cavity band and cavity density. THDS results reveal that the top oxide layer could act as an effective barrier for the migration of helium atoms to the surface, and it thus gives rise to the formation of more overpresurrized bubbles and to the occurrence of a third release peak located at about 1100 K. The results were qualitively discussed by considering the role of the oxide surface layer in defect migration and evolution upon annealing.

  14. Anti-plane (SH) waves diffraction by an underground semi-circular cavity: analytical solution

    Institute of Scientific and Technical Information of China (English)

    Luo Hao; Vincent W. Lee; Liang Jianwen

    2010-01-01

    Diffraction of a two-dimensional (2D) semi-circular cavity in a half-space under incident SH-waves is studied using the classic wave function expansion method with a new de-coupling technique. This so-called "improved cosine half-range expansion" algorithm exhibits an excellent performance in reducing displacement residual errors at two rim points of concern. The governing equations are developed in a manner that minimizes the residues of the boundary conditions. Detailed derivation and analysis procedures as well as truncation of infinite linear governing equations are presented. The semi-circular cavity model presented in this paper, due to its simple profile, is expected to be used in seismic wave propagation studies as a benchmark for examining the accuracies of various analytical or numerical methods for mixed-boundary wave propagation problems.

  15. Numerical and analytical solution for the stationary behaviour of binary mixtures in a horizontal annular cavity heated from inside

    Energy Technology Data Exchange (ETDEWEB)

    Marcoux, M. [Universite Paul Sabatier (IMFT), UMR 5502 CNRS/INP/UPS, Groupe GEMP, 31 - Toulouse (France); Desrayaud, G. [Universite de Picardie Jules Verne, LETEM, INSSET, 80 - Amiens (France); Pagano, A.; Fichera, A. [Universita Degli Studi di Catania, DIIM (Italy)

    2005-07-01

    This work is a study of the behavior of a binary mixture filling a horizontal annulus and subjected to a radial thermal gradient, and therefore to thermo-gravitational diffusion. Numerical simulation of this problem has been carried out for a realistic case and gives a precise description of the mixture in the cavity at steady state. From these observations, a complete analytical resolution of the problem is developed. The solution obtained is validated by comparison with numerical results for a wide range of the non-dimensional parameters controlling the problem. Species separation appearing in this case is finally described, bringing out the influence of the geometry. (authors)

  16. Numerical and analytical solution for the stationary behaviour of binary mixtures in a horizontal annular cavity heated from inside

    International Nuclear Information System (INIS)

    This work is a study of the behavior of a binary mixture filling a horizontal annulus and subjected to a radial thermal gradient, and therefore to thermo-gravitational diffusion. Numerical simulation of this problem has been carried out for a realistic case and gives a precise description of the mixture in the cavity at steady state. From these observations, a complete analytical resolution of the problem is developed. The solution obtained is validated by comparison with numerical results for a wide range of the non-dimensional parameters controlling the problem. Species separation appearing in this case is finally described, bringing out the influence of the geometry. (authors)

  17. Dielectric properties of aqueous solutions of holmium formates

    International Nuclear Information System (INIS)

    SHF-dielectric properties in the range of free-quenches 7-23.5 GHz and electric conductivity of aqueous solutions of holmium formates in the temperature range from 10 to 40 deg C were studied. Parameters of the process of dipole relaxation of water molecules: static dielectric constant, relaxation time and parameters of relaxation time distribution have been ascertained. Activation characteristics of the dipole relaxation and specific electric conductivity have been calculated. The change in the structural-kinetic state of water H-bond net in solution under the action of Ho3+ and HCOO- ions is considered on the basis of the data obtained. 10 refs., 2 figs.; 3 tabs

  18. Formation of three-body entanglement via a vacuum optical cavity induction in Tavis-Cummings model

    Institute of Scientific and Technical Information of China (English)

    Li Yu-Liang; Li Xue-Mei

    2008-01-01

    After briefly introducing Akhtarshenas, concurrence vector and subvector for describing many-body entanglement,we investigate the entanglement formation for a system which contains three bodies, i.e. two identical atoms and a single model cavity field, in the Tavis-Cummings model by calculating the concurrences. The results show that the coupling strength between two atoms, the decay cavity and the atomic spontaneous emission can change the entanglement of formation according to different modes: these factors destroy periodicity and symmetry of all concurrences, and that the coupling strength of two atoms does not change the peak value of concurrence (C), but the strength of decay cavity and the atomic spontaneous emission decline in the peak value of concurrence (C) and the latter is more serious than the former under the same strengths. The concurrence vector and subvector are a useful measure of entanglement for a pure state of the many-body system, in that it can give novel pictures about the entanglements for the entire system and between its inner bodies.

  19. Formation of Cavities at and Away from Grain Boundaries during 600 MeV Proton Irradiation

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Leffers, Torben; Green, W. V.; Green, S. L.

    1982-01-01

    High-purity aluminium (99.9999%) was irradiated with 600 MeV protons at the Swiss Institute for Nuclear Research (SIN) with a damage rate of 3,5 x 10^-6 dpa/s. Irradiation with 600 MeV protons produces helium, hydrogen, and other impurities through mutational reactions. The irradiation experiments...... were carried out at 120 degree C (0,42*Tm where Tm is the melting temperature in K). Transmission electron microscopy on specimens irradiated to 0.2 and 0.6 dpa has shown the presence of (a) cavity-denuded zones (CDZ) along grain boundaries, (b) cavity-containing zones (CCZ) adjacent to the CDZ and (c...

  20. Vertical-Cavity Surface-Emitting Lasers: Advanced Modulation Formats and Coherent Detection

    DEFF Research Database (Denmark)

    Rodes Lopez, Roberto

    This thesis expands the state-of-the-art in coherent detection for optical fiber access networks employing vertical-cavity surface-emitting lasers (VCSELs) as light sources. Bit rates up to 10 Gb/s over 25 km single-mode fibre (SMF) transmission distance have been achieved supporting a passive...... experimentally demonstrated to increase the capacity for a given bandwidth and reduce the impact of optical fiber chromatic dispersion for a given capacity. Finally, 2 Gb/s bipolar impulse-radio ultra-wide band (IR-UWB) data communication over a combined distance of 25 km SMF optical fiber and 4 m air. These......-generation access networks and high- speed shortrange systems employing vertical-cavity surface-emitting lasers as light sources....

  1. Worming Their Way into Shape: Toroidal Formations in Micellar Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Cardiel Rivera, Joshua J.; Tonggu, Lige; Dohnalkova, Alice; de la Iglesia, Pablo; Pozzo, Danilo C.; Shen, Amy

    2013-11-01

    We report the formation of nanostructured toroidal micellar bundles (nTMB) from a semidilute wormlike micellar solution, evidenced by both cryogenicelectron microscopy and transmission electron microscopy images. Our strategy for creating nTMB involves a two-step protocol consisting of a simple prestraining process followed by flow through a microfluidic device containing an array of microposts, producing strain rates in the wormlike micelles on the order of 105 s^1. In combination with microfluidic confinement, these unusually large strain rates allow for the formation of stable nTMB. Electron microscopy images reveal a variety of nTMB morphologies and provide the size distribution of the nTMB. Small-angle neutron scattering indicates the underlying microstructural transition from wormlike micelles to nTMB. We also show that other flow-induced approaches such as sonication can induce and control the emergence of onion-like and nTMB structures, which may provide a useful tool for nanotemplating.

  2. Magnetite hollow spheres: solution synthesis, phase formation and magnetic property

    International Nuclear Information System (INIS)

    Polycrystalline magnetite hollow spheres with diameter of about 200 nm and shell thickness of 30–60 nm were prepared via a facile solution route. For the reaction, ethylene glycol (EG) served as the reducing agent and soldium acetate played the role of precipitator. In addition, polyvinylpyrrolidone (PVP) served as a surface stabilizer. The morphologies and structures were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The intermediate products at different stages were also studied to shed light on the evolution of phase formation. It revealed that the hollow structure formed via self-assembly of nanocrystallites (about 15 nm) using sodium acetate as mild precipitator. Evidences further pointed out that the Ostwald ripening process well explained the growth mechanism of the hollow structure. Magnetization measurements showed that the coercivity of magnetite hollow spheres at low temperature is about 200 Oe and the saturation magnetization is about 83 emu g−1, roughly 85% that of the bulk phase, close to the value of its solid counterpart. In addition, a freezing transition was observed at 25 K.

  3. Formation and reactivity of phenylperoxyl radicals in aqueous solutions

    International Nuclear Information System (INIS)

    The reaction of phenyl radicals with oxygen, to produce phenylperoxyl radicals, and the reactions of several phenylperoxyl radicals with a number of organic compounds in aqueous solutions have been studied by pulse radiolysis. Phenyl radicals were produced by reduction of aryl halides with hydrated electrons. The rate constant for the reaction of 4-carboxyphenyl with O2 was determined from the rate of buildup of the peroxyl radical absorption at 520 nm as a function of [O2] and found to be 1.6 x 109 L mol-1 s-1. Phenyl radicals react with 2-PrOH by H abstraction; a rate constants of 4 x 106 L mol-1 s-1 was determined for 4-carboxyphenyl by competition with the reaction of this radical with O2. Phenylperoxyl radicals react with 4-methoxyphenolate ions, trolox C(6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), ascorbate ions, chlorpromazine, and ABTS [2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate ion)] by one-electron oxidation. The rate constants for such reactions, determined from the rate of formation of the one-electron oxidation product as a function of substrate concentration, were found to be near 108-109 L mol-1 s-1. 24 refs., 4 figs., 1 tab

  4. Relativistic electron Wigner crystal formation in a cavity for electron acceleration

    CERN Document Server

    Thomas, Johannes; Pukhov, Alexander

    2014-01-01

    It is known that a gas of electrons in a uniform neutralizing background can crystallize and form a lattice if the electron density is less than a critical value. This crystallization may have two- or three-dimensional structure. Since the wake field potential in the highly-nonlinear-broken-wave regime (bubble regime) has the form of a cavity where the background electrons are evacuated from and only the positively charged ions remain, it is suited for crystallization of trapped and accelerated electron bunch. However, in this case, the crystal is moving relativistically and shows new three-dimensional structures that we call relativistic Wigner crystals. We analyze these structures using a relativistic Hamiltonian approach. We also check for stability and phase transitions of the relativistic Wigner crystals.

  5. Dynamical formation of a Reissner-Nordstr\\"om black hole with scalar hair in a cavity

    CERN Document Server

    Sanchis-Gual, Nicolas; Herdeiro, Carlos; Font, José A; Montero, Pedro J

    2016-01-01

    In a recent letter, we presented numerical relativity simulations, solving the full Einstein--Maxwell--Klein-Gordon equations, of superradiantly unstable Reissner-Nordstr\\"om black holes (BHs), enclosed in a cavity. Low frequency, spherical perturbations of a charged scalar field, trigger this instability. The system's evolution was followed into the non-linear regime, until it relaxed into an equilibrium configuration, found to be a $\\textit{hairy}$ BH: a charged horizon in equilibrium with a scalar field condensate, whose phase is oscillating at the (final) critical frequency. Here, we investigate the impact of adding self-interactions to the scalar field. In particular, we find sufficiently large self-interactions suppress the exponential growth phase, known from linear theory, and promote a non-monotonic behaviour of the scalar field energy. Furthermore, we discuss in detail the influence of the various parameters in this model: the initial BH charge, the initial scalar perturbation, the scalar field char...

  6. Formation and characterization of nanoparticles via laser ablation in solution

    Science.gov (United States)

    Golightly, Justin Samuel

    The work presented in this thesis encompassed laser ablation of various transition metals within a liquid environment. Through an improved understanding of the ablation process, control over the properties of the resultant nanoparticles can be obtained, and thusly nanoparticles can be tailored with specific properties. Creation of nanoparticles via laser ablation in solution is a relatively youngtechnique for nanoparticle synthesis, and the work presented should prove useful in guiding further exploration in ablation processes in liquids for nanomaterial production. When a laser is focused onto a target under a liquid environment, the target material and its surrounding liquid are vaporized. The concoction of vapor is ejected normal to the surface as a bubble. The bubble has a temperature reaching the boiling point of the metal, and has a gradient to the boiling point of the solvent. The bubble expands until it reaches a critical volume, and then subsequently collapses. It is within this bubble that nanoparticle formation occurs. As the bubble expands, the vapor cools and nanoparticle growth transpires. During the bubble collapse, pressures reaching GigaPascals have been reported, and a secondary nanoparticle formation occurs as a result of these high pressures. Chapter 1 delves a little more into the nanoparticle formation mechanisms, as well as an introduction to the analytical techniques used for characterization. Ablation of titanium took place in isopropanol, ethanol, water, and n-hexane, under various fluences, with a 532 nm Nd:YAG operating at 10 Hz. It was found that a myriad of nanoparticles could be made with vastly different compositions that were both solvent and fluence dependent. Nanoparticles were made that incorporated carbon and oxygen from the solvent, showing how solvent choice is an important factor in nanoparticle creation. Chapter 3 discusses the results of the titanium work in great detail and demonstrates carbide production with ablation in

  7. Dosimetric consideration for patients with dental filling materials undergoing irradiation of oral cavity using RapidArc: challenges and solution

    Science.gov (United States)

    Mail, Noor; Albarakati, Y.; Khan, M. Ahmad; Saeedi, F.; Safadi, N.; Al-Ghamdi, S.; Saoudi, A.

    2012-03-01

    In this study, we investigate the effect of dental filling materials (DFM) on RapidArcTM treatment plans and delivery in a patient undergoing radiotherapy treatment. The presence of DFM creates uncertainties in CT number and causes long streaking artifacts in the reconstructed images which greatly affect the dose distribution inside the oral cavity. The influence of extensive dental filling artifacts on dose distribution was performed using a geometrically well defined head and neck IMRT verification phantom (PTW, Freiburg, Germany) together with inserts from DFM (Amalgam, 11.3 g/cm3). The phantom was scanned using Siemens SOMATOM Sensation CT simulator (Siemens AG, Germany) under standard head and neck imaging protocol (120 kV, 120 mAs, voxel size 1×1×2 mm3). Three RapidArcTM plans were created in the Varian Eclipse treatment planning System (TPS) to treat oral cavity using the same CT dataset including; 1) raw CT image, 2) streaking artifacts replaced with a mask of 10 HU and 3) 2 cm thick 6000 HU virtual filter (a volume around the teeth in TPS to mimic extra attenuation). The virtual filter thickness optimization was purely based on measured PDD data acquired with DFM and the calculation in Eclipse Planning System using direct beam. The dose delivery and distribution for the three plans was verified using Gafchromic EBT2 (International Specialty Product, Wayne, NJ, USA) film measurements. The artifact mask and virtual filter around the teeth in the planning was found very useful to reduce the discrepancies between the dose plan and delivery. From clinical point of view, these results can be helpful to understand the increase of mucositis in patient having DFM, and further investigation is underway for clinical solution.

  8. Formation mechanisms, structure, solution behavior, and reactivity of aminodiborane.

    Science.gov (United States)

    Li, Huizhen; Ma, Nana; Meng, Wenjuan; Gallucci, Judith; Qiu, Yongqing; Li, Shujun; Zhao, Qianyi; Zhang, Jie; Zhao, Ji-Cheng; Chen, Xuenian

    2015-09-30

    A facile synthesis of cyclic aminodiborane (NH2B2H5, ADB) from ammonia borane (NH3·BH3, AB) and THF·BH3 has made it possible to determine its important characteristics. Ammonia diborane (NH3BH2(μ-H)BH3, AaDB) and aminoborane (NH2BH2, AoB) were identified as key intermediates in the formation of ADB. Elimination of molecular hydrogen occurred from an ion pair, [H2B(NH3) (THF)](+)[BH4](-). Protic-hydridic hydrogen scrambling was proved on the basis of analysis of the molecular hydrogen products, ADB and other reagents through (2)H NMR and MS, and it was proposed that the scrambling occurred as the ion pair reversibly formed a BH5-like intermediate, [(THF)BH2NH2](η(2)-H2)BH3. Loss of molecular hydrogen from the ion pair led to the formation of AoB, most of which was trapped by BH3 to form ADB with a small amount oligomerizing to (NH2BH2)n. Theoretical calculations showed the thermodynamic feasibility of the proposed intermediates and the activation processes. The structure of the ADB·THF complex was found from X-ray single crystal analysis to be a three-dimensional array of zigzag chains of ADB and THF, maintained by hydrogen and dihydrogen bonding. Room temperature exchange of terminal and bridge hydrogens in ADB was observed in THF solution, while such exchange was not observed in diethyl ether or toluene. Both experimental and theoretical results confirm that the B-H-B bridge in ADB is stronger than that in diborane (B2H6, DB). The B-H-B bridge is opened when ADB and NaH react to form sodium aminodiboronate, Na[NH2(BH3)2]. The structure of the sodium salt as its 18-crown-6 ether adduct was determined by X-ray single crystal analysis. PMID:26335760

  9. Bistability and domain formation in driven-dissipative photon cavity arrays

    Science.gov (United States)

    Foss-Feig, Michael; Wilson, Ryan; Gorshkov, Alexey

    2016-05-01

    Atomic, molecular, and optical systems afford exciting opportunities to engineer simple, driven-dissipative quantum systems. Even when these systems reach a steady state, they generally remain far from thermal equilibrium, creating many difficulties in describing them theoretically. We confront some of these difficulties in a simple context by studying coupled arrays of non-linear optical cavities. In the limit of strong photon-photon interactions, and making a mean-field approximation, this system exhibits collective bistability between bright and dark states, in close analogy to single-mode quantum optical systems studied decades ago. While this mean-field picture hints at the existence of a first-order phase transition in the true steady state, we are unaware of any general arguments for whether, and if so in what spatial dimensions, such a transition actually exists; the answer depends upon the detailed dynamics of domains in the presence of both quantum and dissipative fluctuations. We study the effects of such fluctuations at various levels of approximation, and develop some simple qualitative pictures of what is going on in the true quantum steady state.

  10. Evaluation of Cavity Collapse and Surface Crater Formation for Selected Lawrence Livermore National Laboratory Underground Nuclear Tests - 2011, Part 2

    Energy Technology Data Exchange (ETDEWEB)

    Pawloski, G A

    2012-01-30

    This report evaluates collapse evolution for selected Lawrence Livermore National Laboratory (LLNL) underground nuclear tests at the Nevada National Security Site (NNSS, formerly called the Nevada Test Site). The work is being done to support several different programs that desire access to the ground surface above expended underground nuclear tests. The programs include: the Borehole Management Program, the Environmental Restoration Program, and the National Center for Nuclear Security Gas-Migration Experiment. Safety decisions must be made before a crater area, or potential crater area, can be reentered for any work. Evaluation of cavity collapse and crater formation is input into the safety decisions. Subject matter experts from the LLNL Containment Program who participated in weapons testing activities perform these evaluations. Information used included drilling and hole construction, emplacement and stemming, timing and sequence of the selected test and nearby tests, geology, yield, depth of burial, collapse times, surface crater sizes, cavity and crater volume estimations, ground motion, and radiological release information. Both classified and unclassified data were reviewed. The evaluations do not include the effects of erosion that may modify the collapse craters over time. They also do not address possible radiation dangers that may be present. Various amounts of information are available for these tests, depending on their age and other associated activities. Lack of data can hamper evaluations and introduce uncertainty. We make no attempt to quantify this uncertainty. Evaluation of Cavity Collapse and Surface Crater Formation for Selected Lawrence Livermore National Laboratory Underground Nuclear Tests - 2011 was published on March 2, 2011. This report, considered Part 2 of work undertaken in calendar year 2011, compiles evaluations requested after the March report. The following unclassified summary statements describe collapse evolution and crater

  11. External-Cavity Quantum Cascade Laser Spectroscopy for Mid-IR Transmission Measurements of Proteins in Aqueous Solution.

    Science.gov (United States)

    Alcaráz, Mirta R; Schwaighofer, Andreas; Kristament, Christian; Ramer, Georg; Brandstetter, Markus; Goicoechea, Héctor; Lendl, Bernhard

    2015-07-01

    In this work, we report mid-IR transmission measurements of the protein amide I band in aqueous solution at large optical paths. A tunable external-cavity quantum cascade laser (EC-QCL) operated in pulsed mode at room temperature allowed one to apply a path length of up to 38 μm, which is four times larger than that applicable with conventional FT-IR spectrometers. To minimize temperature-induced variations caused by background absorption of the ν2-vibration of water (HOH-bending) overlapping with the amide I region, a highly stable temperature control unit with relative temperature stability within 0.005 °C was developed. An advanced data processing protocol was established to overcome fluctuations in the fine structure of the emission curve that are inherent to the employed EC-QCL due to its mechanical instabilities. To allow for wavenumber accuracy, a spectral calibration method has been elaborated to reference the acquired IR spectra to the absolute positions of the water vapor absorption bands. Employing this setup, characteristic spectral features of five well-studied proteins exhibiting different secondary structures could be measured at concentrations as low as 2.5 mg mL(-1). This concentration range could previously only be accessed by IR measurements in D2O. Mathematical evaluation of the spectral overlap and comparison of second derivative spectra confirm excellent agreement of the QCL transmission measurements with protein spectra acquired by FT-IR spectroscopy. This proves the potential of the applied setup to monitor secondary structure changes of proteins in aqueous solution at extended optical path lengths, which allow experiments in flow through configuration. PMID:26059222

  12. Solution mining systems and methods for treating hydrocarbon containing formations

    Science.gov (United States)

    Vinegar, Harold J.; de Rouffignac, Eric Pierre; Schoeling, Lanny Gene

    2009-07-14

    A method for treating an oil shale formation comprising nahcolite is disclosed. The method includes providing a first fluid to a portion of the formation through at least two injection wells. A second fluid is produced from the portion through at least one injection well until at least two injection wells are interconnected such that fluid can flow between the two injection wells. The second fluid includes at least some nahcolite dissolved in the first fluid. The first fluid is injected through one of the interconnected injection wells. The second fluid is produced from at least one of the interconnected injection wells. Heat is provided from one or more heaters to the formation to heat the formation. Hydrocarbon fluids are produced from the formation.

  13. Coupled procedure of integral Psub(L) and differential Ssub(N) approximation of the transport equation for the solution of streaming problems for big cavities

    International Nuclear Information System (INIS)

    The transport equation is solved by means of the Psub(L)-approximation in the cavities and Ssub(N)-approximation in the surrounding materials. The coupling of these approximations is achieved by general boundary conditions of Psub(L)-approximation. Separate Legendre expansions in four directional quadrants take care of strong directional streaming through cavities. To solve the Psub(L)-approximation for particle transport a modular program has been developed. The coupling of this program with a well proved Ssub(N)-code leads to a user friendly program system. The results of the new method have been compared with exact solutions of different problems found in literature and for certain self-defined problems derived from streaming calculations through the top reflector of a high temperature reactor. It is shown, that for big cavities with great flux gradients along the boundaries the results of the coupled method are much better than those of Ssub(N)-calculations. (orig.)

  14. Evaluation of Cavity Collapse and Surface Crater Formation for Selected Lawrence Livermore National Laboratory Underground Nuclear Tests - 2006

    Energy Technology Data Exchange (ETDEWEB)

    Pawloski, G A; Raschke, K

    2006-03-16

    This report describes evaluation of collapse evolution for selected LLNL underground nuclear tests at the Nevada Test Site (NTS). The work is being done at the request of Bechtel Nevada and supports the Department of Energy National Nuclear Security Association Nevada Site Office Borehole Management Program (BMP). The primary objective of this program is to close (plug) weapons program legacy boreholes that are deemed no longer useful. Safety decisions must be made before a crater area, or potential crater area, can be reentered for any work. Our statements on cavity collapse and crater formation are input into their safety decisions. The BMP is an on-going program to address hundreds of boreholes at the NTS. Each year Bechtel Nevada establishes a list of holes to be addressed. They request the assistance of the Lawrence Livermore National Laboratory and Los Alamos National Laboratory Containment Programs to provide information related to the evolution of collapse history and make statements on completeness of collapse as relates to surface crater stability. These statements do not include the effects of erosion that may modify the collapse craters over time. They also do not address possible radiation dangers that may be present. Subject matter experts from the LLNL Containment Program and the Chemistry Biology and Nuclear Sciences Division who had been active in weapons testing activities performed these evaluations. Information used included drilling and hole construction, emplacement and stemming, timing and sequence of the selected test and nearby tests, geology, yield, depth of burial, collapse times, surface crater sizes, cavity and crater volume estimations, and ground motion. Both classified and unclassified data were reviewed. Various amounts of information are available for these tests, depending on their age and other associated activities. Lack of data can hamper evaluations and introduce uncertainty. We make no attempt to quantify this uncertainty.

  15. Evaluation of Cavity Collapse and Surface Crater Formation for Selected Lawrence Livermore National Laboratory Underground Nuclear Tests - 2007

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, S K; Pawloski, G A; Raschke, K

    2007-04-26

    This report describes evaluation of collapse evolution for selected LLNL underground nuclear tests at the Nevada Test Site (NTS). The work is being done at the request of NSTec and supports the Department of Energy National Nuclear Security Association Nevada Site Office Borehole Management Program (BMP). The primary objective of this program is to close (plug) weapons program legacy boreholes that are deemed no longer useful. Safety decisions must be made before a crater area, or potential crater area, can be reentered for any work. Our statements on cavity collapse and crater formation are input into their safety decisions. The BMP is an on-going program to address hundreds of boreholes at the NTS. Each year NSTec establishes a list of holes to be addressed. They request the assistance of the Lawrence Livermore National Laboratory and Los Alamos National Laboratory Containment Programs to provide information related to the evolution of collapse history and make statements on completeness of collapse as relates to surface crater stability. These statements do not include the effects of erosion that may modify the collapse craters over time. They also do not address possible radiation dangers that may be present. Subject matter experts from the LLNL Containment Program and the Chemical Sciences Division who had been active in weapons testing activities performed these evaluations. Information used included drilling and hole construction, emplacement and stemming, timing and sequence of the selected test and nearby tests, geology, yield, depth of burial, collapse times, surface crater sizes, cavity and crater volume estimations, and ground motion. Both classified and unclassified data were reviewed. Various amounts of information are available for these tests, depending on their age and other associated activities. Lack of data can hamper evaluations and introduce uncertainty. We make no attempt to quantify this uncertainty. The following unclassified summary

  16. Pattern formation in solutal convection: vermiculated rolls and isolated cells

    Science.gov (United States)

    Cartwright, Julyan H. E.; Piro, Oreste; Villacampa, Ana I.

    2002-11-01

    Observations of the peculiar behaviour of a drink of liqueur topped with cream led us to perform experiments showing that the instability is a convection phenomenon that arises through destabilizing surface-tension forces. The convection is solutal: driven by gradients of concentration of a solute, rather than by heat gradients as in the more commonly studied thermal convection. The convective patterns, vermiculated rolls and isolated cells, are quite unlike the usual planforms. They are associated with an elastic surface film, and the Marangoni number is high, characteristic of solutal convection. We have conducted further experiments that reproduce these patterns in simpler working fluids.

  17. Nanoscale lubricating film formation by linear polymer in aqueous solution

    Science.gov (United States)

    Liu, Shuhai; Guo, Dan; Xie, Guoxin

    2012-11-01

    Film-forming properties of polymer in aqueous solution flowing through a nanogap have been investigated by using a thin film interferometry. The film properties of linear polymer in aqueous solution flowing through a confined nanogap depend on the ratio of water film thickness to averaged radius of polymer chains H0/RPolymer. It was found that the lubrication film thickness of linear polymer in aqueous solution decreases as the polymer molecular weight increasing when H0/RPolymer < 2 ˜ 3. A new lubrication map was proposed, which includes the lubrication regime of weak confinement influence, the lubrication regime of strong confinement influence (LRSCI), and the transition regime of confinement influence. It is very difficult to increase the lubrication film thickness using the higher molecule weight in the LRSCI regime. The lubrication mechanism inferred from our experimental results may help to better understand the dynamic film properties of linear polymer in aqueous solution flowing through a nanogap.

  18. Formation of long-lived resonances in hexagonal cavities by strong coupling of superscar modes

    Science.gov (United States)

    Song, Qinghai; Ge, Li; Wiersig, Jan; Cao, Hui

    2013-08-01

    The recent progresses in single crystalline wide bandgap hexagonal disk have stimulated intense research attention on pursuing ultraviolet (UV) laser diodes with low thresholds. While whispering-gallery modes based UV lasers have been successfully obtained in GaN, ZnO nanorods, and nanopillars, the reported thresholds are still very high, due to the low-quality (Q) factors of the hexagonal resonances. Here we demonstrate resonances whose Q factors can be more than two orders of magnitude higher than the hexagonal modes, promising the reduction of the energy consumption. The key to our finding is the avoided resonance crossing between superscar states along two sets of nearly degenerated triangle orbits, which leads to the formation of hexagram modes. The mode couplings suppress the field distributions at the corners and the deviations from triangle orbits simultaneously and therefore enhance the Q factors significantly.

  19. Lipid Bilayer Formation in Aqueous Solutions of Ionic Liquids

    OpenAIRE

    Young, Taylor Tront

    2012-01-01

    The formation of lipid bilayer membranes between droplets of ionic liquid is presented as a means of forming functional bimolecular networks for use in sensor applications. Ionic liquids are salts that have a number of useful properties, such as low melting points making them liquid at room temperature and exceedingly low vapor pressure. Ionic liquids have seen recent popularity as environmentally friendly industrial solvent alternatives. Our research demonstrates that it is possible to cons...

  20. Role of cavity formation in SCC of cold worked carbon steel in high-temperature water. Part 2. Study of crack initiation behavior

    International Nuclear Information System (INIS)

    To consider the role of cavity formation in stress corrosion cracking (SCC) of cold worked (CW) carbon steel in high-temperature water, SCC and creep growth (part 1) and initiation (part 2) tests were performed. The part 2 crack initiation tests used blunt notched compact tension (CT) type specimens of CW carbon steel exposed under the static load condition in hydrogenated pure water and in air in the range of temperatures between 360 and 450°C. Inter-granular (IG) crack initiation was observed both in water and in air even in static load condition when steel specimens had been cold worked. 1/T type temperature dependencies of initiation times were observed for CW carbon steel, and the crack initiation times in an operating pressurized heavy water reactor, PHWR (Pt Lepreau) seemed to lie on the extrapolated line of the experimental results. Cavities were identified at the grain boundaries near the bottom of a notch (highly stressed location) before cracks initiated both in water and air. The cavities were probably formed by the condensation of vacancies and they affected the bond strength of the grain boundaries. To assess the mechanism of IGSCC initiation in high temperature water, the diffusion of vacancies driven by stress gradients was studied using a specially designed CT specimen. As a model for IGSCC in CW carbon steel in high temperature water, it was concluded that the formation of cavities from the collapse of vacancies offers the best interpretation of the present data. (author)

  1. Radiolysis of concentrated solution of nitrate and formate

    International Nuclear Information System (INIS)

    We have studied the influence of specific scavengers of solvated electron, the potassium nitrate and of OH radical, the sodium formate on the decomposition on water submitted to γ rays. By the analysis of the final products we have been able to determine the radical and molecular yields in function of the concentration of the scavengers and compare their evolution with the theoretical prediction of the spurs model. We have also studied the influence of oxygen and the importance of the direct effect of γ rays on the scavengers. The results show that the yields of the molecular products H2 and H2O2 and the atomic hydrogen yield decrease in function of the concentration of the scavengers in conformity with the prevision of the spurs model, while the yield of solvated electron and OH radical increases. The total yield of decomposition of water increases until the value of 4,6±0,3 (author)

  2. Stationary solution of a weak-driven open Jaynes-Cummings system of a degenerate two-level atom coupled to an arbitrary-polarized cavity field

    CERN Document Server

    Kang, Sungsam; Lim, Sooin; Kim, Wookrae; Lee, Jai-Hyung; An, Kyungwon

    2009-01-01

    Analytical solution for the stationary density matrix is derived, by using the Morris-Shore transformation, for an open Jaynes-Cummings system (JCM) of a two-level atom with Zeeman sublevel degeneracy coupled to an arbitrary-polarized cavity mode. In the limit of weak excitation with the number of quantum in the system not exceeding one, we have obtained the stationary solution of the master equation up to the first order of the driving field intensity. We have also derived the analytic expressions for the excitation spectra of atomic spontaneous emission and cavity transmission. Our results show that the system can be regarded as a non-degenerate two-level system with a single effective coupling constant which depends only on the elliptic angle of the driving field as long as the atom-cavity coupling is not too strong. A precise condition for this approximation is derived. This work provides a theoretical ground for experimentally realizing a JCM with a coupling constant continuously varied for various cavit...

  3. Verification of the NIKE3D structural analysis code by comparison against the analytic solution for a spherical cavity under a far-field uniaxial stress

    Energy Technology Data Exchange (ETDEWEB)

    Kansa, E.J.

    1989-01-01

    The original scope of this task was to simulate the stresses and displacements of a hard rock tunnel experimental design using a suitable three-dimensional finite element code. NIKE3D was selected as a suitable code for performing these primarily approximate linearly elastic 3D analyses, but it required modifications to include initial stress, shear traction boundary condition and excavation options. During the summer of 1988, such capabilities were installed in a special version of NIKE3D. Subsequently, we verified both the LLNL's commonly used version of NIKE3D and our private modified version against the analytic solution for a spherical cavity in an elastic material deforming under a far-field uniaxial stress. We find the results produced by the unmodified and modified versions of NIKE3D to be in good agreement with the analytic solutions, except near the cavity, where the errors in the stress field are large. As can be expected from a code based on a displacement finite element formulation, the displacements are much more accurate than the stresses calculated from the 8-noded brick elements. To reduce these errors to acceptable levels, the grid must be refined further near the cavity wall. The level of grid refinement required to simulate accurately tunneling problems that do not have spatial symmetry in three dimensions using the current NIKE3D code is likely to exceed the memory capacity of the largest CRAY 1 computers at LLNL. 8 refs., 121 figs.

  4. Verification of the NIKE3D structural analysis code by comparison against the analytic solution for a spherical cavity under a far-field uniaxial stress

    International Nuclear Information System (INIS)

    The original scope of this task was to simulate the stresses and displacements of a hard rock tunnel experimental design using a suitable three-dimensional finite element code. NIKE3D was selected as a suitable code for performing these primarily approximate linearly elastic 3D analyses, but it required modifications to include initial stress, shear traction boundary condition and excavation options. During the summer of 1988, such capabilities were installed in a special version of NIKE3D. Subsequently, we verified both the LLNL's commonly used version of NIKE3D and our private modified version against the analytic solution for a spherical cavity in an elastic material deforming under a far-field uniaxial stress. We find the results produced by the unmodified and modified versions of NIKE3D to be in good agreement with the analytic solutions, except near the cavity, where the errors in the stress field are large. As can be expected from a code based on a displacement finite element formulation, the displacements are much more accurate than the stresses calculated from the 8-noded brick elements. To reduce these errors to acceptable levels, the grid must be refined further near the cavity wall. The level of grid refinement required to simulate accurately tunneling problems that do not have spatial symmetry in three dimensions using the current NIKE3D code is likely to exceed the memory capacity of the largest CRAY 1 computers at LLNL. 8 refs., 121 figs

  5. Formation of quasi-free and bubble positronium states in water and aqueous solutions

    CERN Document Server

    Stepanov, Serge V; Byakov, Vsevolod M; Zvezhinskiy, D S; Subrahmanyam, V S

    2013-01-01

    It is shown that in aqueous solutions a positronium atom is first formed in the quasi-free state, and, after 50-100 ps, becomes localized in a nanobubble. Analysis of the annihilation spectra of NaNO3 aqueous solutions shows that the hydrated electron is not involved in the positronium (Ps) formation.

  6. Numerical Solution of Stokes Flow in a Circular Cavity Using Mesh-free Local RBF-DQ

    DEFF Research Database (Denmark)

    Kutanaai, S Soleimani; Roshan, Naeem; Vosoughi, A; Saghafi, S; Barari, Amin; Soleimani, Soheil

    2012-01-01

    This work reports the results of a numerical investigation of Stokes flow problem in a circular cavity as an irregular geometry using mesh-free local radial basis function-based differential quadrature (RBF-DQ) method. This method is the combination of differential quadrature approximation of der...

  7. Study of the formation of solute clusters under irradiation in model ferritic alloys

    International Nuclear Information System (INIS)

    Neutron irradiation results in the formation of a high number density (1023 to 1024 m-3) of ultrafine (2 nm in diameter) solute clusters in reactor vessel steels. These clusters contain a supersaturated element (copper), and some others solutes (Mn, Ni, Si and P) soluble at the temperature of irradiation (300 C). The aim of the work described in this report is to understand what are the basic processes at the origin of the formation of these clusters, and to obtain information about the effect of the different solutes. The microstructure of model alloys, after different irradiation experiments is characterised by atom probe. The comparison between experimental results and results obtained by mean field modelling (evolution of point defects under irradiation) suggests that the precipitation of the solute clusters is heterogeneous, on point defects clusters. Precipitation kinetic is slowed down by solutes other than copper. (author)

  8. Electrical conductivity of Jupiter's shallow interior and the formation of a resonant of a resonant planetary-ionospheric cavity

    International Nuclear Information System (INIS)

    The present consideration of hydrogenic atmospheric reactions on Jupiter, to a depth of 4000 km, notes the primary ion constituents at these depths to be both positive and negative ions of molecular hydrogen contributing less than 20 percent to total electrical conductivity by free electrons. An electrical surface defined by the boundary beneath which the interior is electrically conducting exists at depths which vary according to EM wave frequency, from 1100 km for 1 mHz to 3000 for 1 MHz. The presence of a lower electrical boundary within the shallow interior suggests that a planetary-ionosphere resonant cavity analogous to the earth-ionosphere cavity may exist. 36 refs

  9. Walk-off-induced modulation instability, temporal pattern formation, and frequency comb generation in cavity-enhanced second-harmonic generation

    CERN Document Server

    Leo, F; Ricciardi, I; De Rosa, M; Coen, S; Wabnitz, S; Erkintalo, M

    2016-01-01

    We derive a time-domain mean-field equation to model the full temporal and spectral dynamics of light in singly resonant cavity-enhanced second-harmonic generation systems. We show that the temporal walk-off between the fundamental and the second-harmonic fields plays a decisive role under realistic conditions, giving rise to rich, previously unidentified nonlinear behaviour. Through linear stability analysis and numerical simulations, we discover a new kind of quadratic modulation instability which leads to the formation of optical frequency combs and associated time-domain dissipative structures. Our numerical simulations show excellent agreement with recent experimental observations of frequency combs in quadratic nonlinear media [Phys. Rev. A 91, 063839 (2015)]. Thus, in addition to unveiling a new, experimentally accessible regime of nonlinear dynamics, our work enables predictive modeling of frequency comb generation in cavity-enhanced second-harmonic generation systems.

  10. Formation of solid solutions in the systems of calcium and lanthanum (samarium, europium) orthovanadates

    International Nuclear Information System (INIS)

    Phase ratios in the systems Ca3(VO4)2-MVO4, where M=La, Sm, Eu, have been studied. Formation of solid solutions Casub(3(1-x))Msub(2x)(VOsub(4))sub(2) at 0 3(VO4)2-LaVO4 in the range 0.27 3=(PO4)2 type is confirmed. It is established, that the formation of solid solutions on the basis of Ca3(VO4)2 structure takes place according to substitution-subtraction mechanism

  11. Modeling hydrate formation conditions in the presence of electrolytes and polar inhibitor solutions

    International Nuclear Information System (INIS)

    Highlights: • A new predictive model is proposed for prediction of hydrate formation pressures. • A new local composition model was used to evaluate water activity in the presence of electrolyte. • MEG, DEG and TEG were used to test ability of the proposed model in the presence of polar inhibitors. • Cage occupancies by methane for the small cage were higher than carbon dioxide for gas mixtures. • The proposed model gives better match with experimental data in mixed electrolyte solutions. - Abstract: In this paper, a new predictive model is proposed for prediction of gas hydrate formation conditions in the presence of single and mixed electrolytes and solutions containing both electrolyte and a polar inhibitor such as monoethylene glycol (MEG), diethylene glycol (DEG) and triethylene glycol (TEG). The proposed model is based on the γ–φ approach, which uses modified Patel–Teja equation of state (VPT EOS) for characterizing the vapor phase, the solid solution theory by van der Waals and Platteeuw for modeling the hydrate phase, the non-electrolyte NRTL-NRF local composition model and Pitzer–Debye–Huckel equation as short-range and long-range contributions to calculate water activity in single electrolyte solutions. Also, the Margules equation was used to determine the activity of water in solutions containing polar inhibitor (glycols). The model predictions are in acceptable agreement with experimental data. For single electrolyte solutions, the model predictions are similar to available models, while for mixtures of electrolytes and mixtures of electrolytes and inhibitors, the proposed model gives significantly better predictions. In addition, the absolute average deviation of hydrate formation pressures (AADP) for 144 experimental data in solutions containing single electrolyte is 5.86% and for 190 experimental data in mixed electrolytes solutions is 5.23%. Furthermore, the proposed model has an AADP of 14.13%, 5.82% and 5.28% in solutions

  12. Crab Cavities for Linear Colliders

    International Nuclear Information System (INIS)

    Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favour a 3.9 GHz superconducting, multi-cell cavity as the solution for ILC, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are fundamental issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders.

  13. Crab Cavities for Linear Colliders

    Energy Technology Data Exchange (ETDEWEB)

    Burt, G.; Ambattu, P.; Carter, R.; Dexter, A.; Tahir, I.; /Cockcroft Inst. Accel. Sci. Tech. /Lancaster U.; Beard, C.; Dykes, M.; Goudket, P.; Kalinin, A.; Ma, L.; McIntosh, P.; /Daresbury; Shulte, D.; /CERN; Jones, Roger M.; /Cockcroft Inst. Accel. Sci. Tech. /Manchester U.; Bellantoni, L.; Chase, B.; Church, M.; Khabouline, T.; Latina, A.; /Fermilab; Adolphsen, C.; Li, Z.; Seryi, Andrei; /SLAC

    2011-11-08

    Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favour a 3.9 GHz superconducting, multi-cell cavity as the solution for ILC, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are fundamental issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders.

  14. Crab cavities for linear colliders

    CERN Document Server

    Burt, G; Carter, R; Dexter, A; Tahir, I; Beard, C; Dykes, M; Goudket, P; Kalinin, A; Ma, L; McIntosh, P; Shulte, D; Jones, Roger M; Bellantoni, L; Chase, B; Church, M; Khabouline, T; Latina, A; Adolphsen, C; Li, Z; Seryi, Andrei; Xiao, L

    2008-01-01

    Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favour a 3.9 GHz superconducting, multi-cell cavity as the solution for ILC, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are fundamental issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders.

  15. The calcium oxide influence on formation of manganese, calcium pyrovanadate solid solutions

    International Nuclear Information System (INIS)

    The X-ray graphic, derivatographic, microscopic and chemical methods are used to study solid solutions of manganese, calcium pyrovanadates containing 1-10 mass% CaO and the products of interaction of reprocessing charges of vanadium-containing converter slags intended for he formation of manganese and calcium pyrovanadates with additions of calcium oxide within 10-90 mass%. It is established that in the case of 1-6 mass% CaO content in manganese pyrovanadate solid interstitial solutions appear, while at 6-20 mass% CaO - solid substitution solutions form. The results of calculating elementary cell parameters as well as melting temperatures and pyrovanadate solid solution solubility depending on CaO content are presented. The best solubility of introduction solid solutions during vanadium extraction according to the lime technology is found

  16. The kinetics of dye formation by pulse radiolysis of pararosaniline cyanide in aqueous or organic solution

    International Nuclear Information System (INIS)

    The radiation-induced conversion of the leucocyanide of pararosaniline dye to the highly colored salt-isomer of the dye in acidic aqueous solution (wavelength of maximum absorption lambda sub(max)=540 nm) or polar organic solution (lambda sub(max)=550 nm), takes place in two separate processes. The first is very fast (within 3 s-1 to 106 s-1, as the acidity or concentration of an oxidizing agent increases. In oxygen-free acidic aqueous or organic solutions (argon saturated) there is an unstable transient species (lambdasub(max)=380 nm). When using O2 or N2O-saturated aqueous or organic solution, there is no intermediate absorption band at 380 nm, but the slow process of dye formation at 540 or 550 nm is still sequential to the initial fast process having somewhat faster kinetics than in Ar-saturated solution. (author)

  17. Formation of non-equilibrium germanium-based solid solutions in al-ge-alloys

    Directory of Open Access Journals (Sweden)

    O.Yu. Bereza

    2012-08-01

    Full Text Available This article is devoted to the investigation of phase composition and microstructure of the higher cooled aluminum-germanium alloys. The formation of non-equilibrium germanium solid solutions is shown. The influence of the rate of cooling and the germanium percentage on the phase composition of alloys is shown.

  18. Solution of the square lid-driven cavity flow of a Bingham plastic using the finite volume method

    CERN Document Server

    Syrakos, Alexandros; Alexandrou, Andreas N

    2016-01-01

    We investigate the performance of the finite volume method in solving viscoplastic flows. The creeping square lid-driven cavity flow of a Bingham plastic is chosen as the test case and the constitutive equation is regularised as proposed by Papanastasiou [J. Rheol. 31 (1987) 385-404]. It is shown that the convergence rate of the standard SIMPLE pressure-correction algorithm, which is used to solve the algebraic equation system that is produced by the finite volume discretisation, severely deteriorates as the Bingham number increases, with a corresponding increase in the non-linearity of the equations. It is shown that using the SIMPLE algorithm in a multigrid context dramatically improves convergence, although the multigrid convergence rates are much worse than for Newtonian flows. The numerical results obtained for Bingham numbers as high as 1000 compare favourably with reported results of other methods.

  19. Crystal Ice Formation of Solution and Its Removal Phenomena From Cooled Solid Surface

    Science.gov (United States)

    Hirata, Tetsuo; Ishikawa, Masaaki; Nagasaka, Kouji

    Experimental studies for freezing phenomena of ethylene glycol solution on cooled plate have been performed. A polyvinyl chloride as well as an acrylic resin plates are used for the cooled plates. It is found that the crystal ice formed at the cooled plate is removed from the plate due to buoyancy force acting the crystal ice. It means that ice formation on a cooled plate without deposit ice layer is possible by the present method. It is shown that the cooled plate surface is under cooled about 1.0~1.5 degree below the freezing temperature of the solution during the crystal ice formation and its removal phenomena. The degree of under cooled temperature is unaffected by the cooling temperature of the plate. For higher concentration of solution, it is found that the number of the removed crystal ice per unit time is increased and the volume of each removed ice is decreased.

  20. Heat-induced formation of myosin oligomer-soluble filament complex in high-salt solution.

    Science.gov (United States)

    Shimada, Masato; Takai, Eisuke; Ejima, Daisuke; Arakawa, Tsutomu; Shiraki, Kentaro

    2015-02-01

    Heat-induced aggregation of myosin into an elastic gel plays an important role in the water-holding capacity and texture of meat products. Here, we investigated thermal aggregation of porcine myosin in high-salt solution over a wide temperature range by dynamic light scattering experiments. The myosin samples were readily dissolved in 1.0 M NaCl at 25 °C followed by dilution into various salt concentrations. The diluted solutions consistently contained both myosin monomers and soluble filaments. The filament size decreased with increasing salt concentration and temperature. High temperatures above Tm led to at least partial dissociation of soluble filaments and thermal unfolding, resulting in the formation of soluble oligomers and binding to the persistently present soluble filaments. Such a complex formation between the oligomers and filaments has never been observed. Our results provide new insight into the heat-induced myosin gelation in high-salt solution. PMID:25445683

  1. Variation in assimilable organic carbon formation during chlorination of Microcystis aeruginosa extracellular organic matter solutions.

    Science.gov (United States)

    Sun, Xingbin; Yuan, Ting; Ni, Huishan; Li, Yanpeng; Hu, Yang

    2016-07-01

    This study investigated the chlorination of Microcystis aeruginosa extracellular organic matter (EOM) solutions under different conditions, to determine how the metabolites produced by these organisms affect water safety and the formation of assimilable organic carbon (AOC). The effects of chlorine dosages, coagulant dosage, reaction time and temperature on the formation of AOC were investigated during the disinfection of M.aeruginosa metabolite solutions. The concentration of AOC followed a decreasing and then increasing pattern with increasing temperature and reaction time. The concentration of AOC decreased and then increased with increasing chlorination dosage, followed by a slight decrease at the highest level of chlorination. However, the concentration of AOC decreased continuously with increasing coagulant dosage. The formation of AOC can be suppressed under appropriate conditions. In this study, chlorination at 4mg/L, combined with a coagulant dose of 40mg/L at 20°C over a reaction time of 12hr, produced the minimum AOC. PMID:27372113

  2. Thermodynamics of the formation of copper(II) complexes with L-histidine in aqueous solution

    Science.gov (United States)

    Gorboletova, G. G.; Metlin, A. A.

    2015-02-01

    The heat effects from the reaction between L-histidine solutions and Cu(NO3)2 solutions at 298.15 K in the 0.2 to 1.0 (KNO3) range of ionic strength are measured by means of direct calorimetry. The experimental data is treated with allowance for the simultaneous proceeding of several processes. The heat effects of the formation of complexes Cu(His)+, Cu(His)2, CuHHis2+, CuH(His){2/+} and CuH2(His){2/2+} are calculated from calorimetric measurements. The standard enthalpies of formation for complexes of L-histidine with Cu2+ ions are obtained via extrapolation to zero ionic strength. The relationship between the thermodynamic characteristics of the formation of complexes of copper(II) with L-histidine and their structure is determined.

  3. On the Construction and Properties of Weak Solutions Describing Dynamic Cavitation

    KAUST Repository

    Miroshnikov, Alexey

    2014-08-21

    We consider the problem of dynamic cavity formation in isotropic compressible nonlinear elastic media. For the equations of radial elasticity we construct self-similar weak solutions that describe a cavity emanating from a state of uniform deformation. For dimensions d=2,3 we show that cavity formation is necessarily associated with a unique precursor shock. We also study the bifurcation diagram and do a detailed analysis of the singular asymptotics associated to cavity initiation as a function of the cavity speed of the self-similar profiles. We show that for stress free cavities the critical stretching associated with dynamically cavitating solutions coincides with the critical stretching in the bifurcation diagram of equilibrium elasticity. Our analysis treats both stress-free cavities and cavities with contents.

  4. Analysis and solution to the cavity defect of baked pruducts%焙烧品空头缺陷分析及解决措施

    Institute of Scientific and Technical Information of China (English)

    洪伟; 陈磊

    2014-01-01

    The cavity defect of baked products is one of the main quality problems in the first-baking process technology, which often happens in domestic manufactures. It has a significant influence on the first-baking production yield, and the quality index in-cluding the structure, strength, electric resistance and functional performance of finished products. According to years of experience in solving the cavity defects in first-baking products, the causes were analyzed and the solutions were put forward.%石墨电极一次焙烧过程中空头缺陷是主要质量问题之一,其对一次焙烧成品率,成品结构、强度、电阻率等质量指标及产品使用性能有明显影响。根据多年对一次焙烧空头问题解决经验对该问题进行分析及提出新的解决措施。

  5. Double layers and plasma-wave resistivity in extragalactic jets: Cavity formation and radio-wave emission

    Science.gov (United States)

    Borovsky, Joseph E.

    1987-01-01

    For estimated values of the currents carried by extragalactic jets, current-driven electrostatic-wave- and electromagnetic-wave-produced resistivities do not occur. Strong plasma double layers, however, may exist within self-maintained density cavities, the relativistic double-layer-emitted electron, and ion beams driving plasma-wave resistivities in the low- and high-potential plasma adjacent to the double layers. The double-layer-emitted electron beams may also emit polarized radio waves via a collective bremsstrahlung process mediated by electrostatic two-stream instabilities.

  6. Double layers and plasma-wave resistivity in extragalactic jets - Cavity formation and radio-wave emission

    Science.gov (United States)

    Borovsky, Joseph E.

    1987-01-01

    Current driven electrostatic-wave- and electromagnetic-wave-produced resistivities do not occur in extragalactic jets for estimated values of the carried currents. Strong plasma double layers, however, may exist within self-maintained density cavities. The relativistic double-layer-emitted electron and ion beams drive plasma-wave resistivities in the low- and high-potential plasma adjacent to the double layers. The double-layer-emitted electron beams may also emit polarized radio waves via a collective bremsstrahlung process mediated by electrostatic two-stream instabilities.

  7. Superconducting cavities

    International Nuclear Information System (INIS)

    The basic properties of superconducting cavities for electron accelerators are discussed with special emphasis on the following topics: technical motivation for the use of superconducting cavities; surface impedance; the critical field of superconductors; anomalous losses; materials other than niobium; technological achievements for accelerating cavities. (author)

  8. Finger-like pattern formation in dilute surfactant pentaethylene glycol monododecyl ether solutions

    Science.gov (United States)

    Kubo, Yoshihide; Yokoyama, Yasuhiro; Tanaka, Shinpei

    2013-04-01

    We report here peculiar finger-like patterns observed during the phase separation process of dilute micellar pentaethylene glycol monododecyl ether solutions. The patterns were composed of parallel and periodic threads of micelle-rich domains. Prior to this pattern formation, the phase separation always started with the appearance of water-rich domains rimmed by the micelle-rich domains. It was found that these rims played a significant role in the pattern formation. We explain this pattern formation using a simple simulation model with disconnectable springs. The simulation results suggested that the spatially inhomogeneous elasticity or connectivity of a transient gel of worm-like micelles was responsible for the rim formation. The rims thus formed lead rim-induced nucleation, growth, and elongation of the domains owing to their small mobility and the elastic frustration around them. These rim-induced processes eventually produce the observed finger-like patterns.

  9. Orientational structure formation of silk fibroin with anisotropic properties in solutions

    International Nuclear Information System (INIS)

    Key words:silk fibroin, dissolution, solution's model systems, gelation, orientational crystallization, optical polarization, longitudinal stream, α - β transition, structure formation, phase transformations, relaxation, anisotropy of swelling and desorption, thermo- and biodegradation. Subjects of the inquiry: silk fibroin is the main subject of investigation. Fibroin's solutions were obtained on the base of water and organic solvents, containing salts. Comparative investigations were carried out by using biosolution - secretion of silkworm, solutions of silk sericin, cotton cellulose, methylcellulose, polystyrene and (co) polycrylonitrile. Aim of the inquiry: the elucidation of the regularities of silk fibroin anisotropic structures formation in the direct generation of orientational ordering in solutions taking into account of influences of its the molecular structures, configuration information, α - β conformational transformations, and development jointly using polarization-optical and hydrodynamic methods to control of structure formation. And also definition of possibility fields for use biopolymers anisotropic structure formation principles. Method of inquiry: birefringence, dispersion optical rotation, circular dichroism, polarization- ultramicroscope, ultracentrifuge, viscosimetry, potentiometry, differential thermal analysis, chromatography, x-ray analysis, spectroscopy. The results achieved and their novelty: the physical regularity amorphous-crystalline fibroin dissolutions in salt-containing solvents based on chains melting, distribution and redistribution were recognized; fibroin statistical parameters, molecular-mass and conformational characteristics were established; It was shown that fibroin molecules turned into fully uncoiled and oriented state with the breakdown decay of α-spiral chain sections by I type phase transition mechanism, but in oriented state with α-spiral conservation by II type transition; the presence of longitudinal field

  10. Helium cavity formation research on oxide dispersed strengthening (ODS) ferritic steels utilizing dual-ion irradiation facility

    International Nuclear Information System (INIS)

    A dual-ion irradiation method is one of the most popular techniques for the research of microstructural evolution of materials under fusion environmental conditions. The application of oxide dispersion strengthened (ODS) ferritic steels is anticipated for realization of high temperature operation of fusion reactors above 600 deg. C. In this research, the investigation of the microstructural evolution of high corrosion resistant ODS steels was performed using the ion irradiation methods. Dual ion-irradiation experiments were performed at the DuET facility, Kyoto University using 6.4 MeV Fe self-ion and 1 MeV helium ion. The irradiation temperatures were 300 and 500 deg. C. The dose, dose rate, and helium over dpa ratio were 20 dpa, 5 x 10-4 dpa/s, and 15 appm/dpa, respectively. The post-irradiation experiments were performed using SEM, TEM and the nano-indentation methods. Significant microstructural evolution of grains and oxides were not observed after the single-ion irradiation at 20 dpa, 500 deg. C. Fine helium cavities were observed in the dual-ion irradiated 19Cr-2W-4Al ODS steel. Fine cavities of approximately several nanometers diameter were densely and uniformly formed in dual-ion irradiated range

  11. Aqueous Solution Preparation of Ruthenium Nanoparticles Using Ammonium Formate as the Reducing Agent

    Institute of Scientific and Technical Information of China (English)

    LIU Shaohong; CHEN Jialin; GUAN Weiming; BI Jun; CHEN Nanguang; CHEN Dengquan; LIU Manmen; SUN Xudong

    2012-01-01

    Ruthenium,one of the platinum group metals,has drawn much attention due to its catalytic behavior,hardness,electrical conductivity and density.Ruthenium particles are usually prepared on a small scale by the polyol process,however,the size of the obtained ruthenium nanoparticles is most below 10 nm.In this work,ruthenium particles about 200 nm in diameter were obtained in aqueous solution by using ammonium formate as the reducing agent.Tohave a better control of particle's size and shape,the effects of PVP,mixing mode,reaction temperature,solution pH and calcination temperature were investigated.

  12. Analytic solutions and Singularity formation for the Peakon b--Family equations

    OpenAIRE

    Coclite, Giuseppe Maria; Gargano, Francesco; Sciacca, Vincenzo

    2012-01-01

    Using the Abstract Cauchy-Kowalewski Theorem we prove that the $b$-family equation admits, locally in time, a unique analytic solution. Moreover, if the initial data is real analytic and it belongs to $H^s$ with $s > 3/2$, and the momentum density $u_0 - u_{0,{xx}}$ does not change sign, we prove that the solution stays analytic globally in time, for $b\\geq 1$. Using pseudospectral numerical methods, we study, also, the singularity formation for the $b$-family equations with the singularity t...

  13. Analytical solutions for flow of horizontal well in compressible, three-dimensional unconsolidated formations

    International Nuclear Information System (INIS)

    A novel mathematical model for single-phase fluid flow from unconsolidated formations to a horizontal well with the consideration of stress-sensitive permeability is presented. The model assumes the formation permeability is an exponential function of the pore pressure. Using a perturbation technique, the model is solved for either constant pressure or constant flux or infinite lateral boundary conditions with closed top and bottom boundaries. Through Laplace transformation, finite Fourier transformation and numerical inversion methods, the solutions are obtained and the pressure response curves are analyzed. The agreement between the analytical solutions in this paper and the numerical results from commercial software (Saphir) is excellent, which manifests the accuracy of the results derived in this paper. (paper)

  14. Indentation-induced formation of low-dimensional Si structures in KOH solution

    Science.gov (United States)

    Yang, Fuqian; Li, Ding

    2010-03-01

    Low-dimensional Si structures, including Si nanobelts and Si micropyramids, were formed on the surface of n-type silicon by microindentation and anisotropic etching in 30 wt% KOH solution at a temperature of 50 °C. The indentation was performed to create local plastic deformation and residual stresses. The residual stresses caused the formation of the Si nanobelts around the sites of indents on the surface of Si (1 1 1) and the Si micropyramids at the sites of indents on the surface of Si (1 0 0). The formation of the Si micropyramids was due to the local 'mask' created by the indentation and the residual stress around the indents. The residual hydrostatic stress at the tensile state increased the local etching rate, which resulted in a surface depression around the indents. The combination of indentation and wet etching process provides a maskless process to potentially produce low-dimensional Si structures in KOH solution at low temperatures.

  15. Indentation-induced formation of low-dimensional Si structures in KOH solution

    International Nuclear Information System (INIS)

    Low-dimensional Si structures, including Si nanobelts and Si micropyramids, were formed on the surface of n-type silicon by microindentation and anisotropic etching in 30 wt% KOH solution at a temperature of 50 0C. The indentation was performed to create local plastic deformation and residual stresses. The residual stresses caused the formation of the Si nanobelts around the sites of indents on the surface of Si (1 1 1) and the Si micropyramids at the sites of indents on the surface of Si (1 0 0). The formation of the Si micropyramids was due to the local 'mask' created by the indentation and the residual stress around the indents. The residual hydrostatic stress at the tensile state increased the local etching rate, which resulted in a surface depression around the indents. The combination of indentation and wet etching process provides a maskless process to potentially produce low-dimensional Si structures in KOH solution at low temperatures.

  16. Formation of solid solutions in the systems of calcium and lanthanum (samarium, europium) orthovanadates

    Energy Technology Data Exchange (ETDEWEB)

    Khodos, M.Ya.; Leonidov, I.A.; Fotiev, A.A. (AN SSSR, Sverdlovsk. Inst. Khimii)

    1984-09-01

    Phase ratios in the systems Ca/sub 3/(VO/sub 4/)/sub 2/-MVO/sub 4/, where M=La, Sm, Eu, have been studied. Formation of solid solutions Casub(3(1-x))Msub(2x) (VOsub(4))sub(2) at 0 < x <= 0.12, having the structure of calcium orthovanadate, is shown. In the system Ca/sub 3/(VO/sub 4/)/sub 2/-LaVO/sub 4/ in the range 0.27 <= x <= 0.33 existence of a phase with the structure of Sr/sub 3/=(PO/sub 4/)/sub 2/ type is confirmed. It is established that the formation of solid solutions on the basis of Ca/sub 3/(VO/sub 4/)/sub 2/ structure takes place according to substitution-subtraction mechanism.

  17. Slow light, open cavity formation, and large longitudinal electric field on slab waveguide made of indefinite-index metamaterials

    CERN Document Server

    Lu, W T

    2009-01-01

    The optical properties of slab waveguides made of indefinite-index metamaterials are considered. The transverse permittivity is negative while the longitudinal permittivity is positive. At any given frequency the waveguide supports an infinite number of transverse magnetic (TM) eigenmodes. For a slab waveguide with a fixed thickness, at most only one TM mode is forward-wave. The rest of them are backward waves which can have very large phase index. At a critical thickness, the waveguide supports degenerate forward- and backward-wave modes with zero group velocity. Above the critical thickness, the waveguide supports complex-conjugate decay modes instead of propagating modes. These slab waveguides can be used to make optical delay lines in optical buffers to slow down and trap light, to form open cavities, to generate strong longitudinal electric fields, and as phase shifters in optical integrated circuits.

  18. TT-GMRES: on solution to a linear system in the structured tensor format

    OpenAIRE

    Dolgov, Sergey V.

    2012-01-01

    A adapted tensor-structured GMRES method for the TT format is proposed and investigated. The Tensor Train (TT) approximation is a robust approach to high-dimensional problems. One class of problems is solution of a linear system. In this work we study the convergence of the GMRES method in the presence of tensor approximations and provide relaxation techniques to improve its performance. Several numerical examples are presented. The method is also compared with a projection TT linear solver b...

  19. Uranium (VI) complexing by macrocyclic or chelating ligands in aqueous solutions stability, formation kinetics, polarographic properties

    International Nuclear Information System (INIS)

    Stability of chelates (with EDTA,N,N ethylenediamine diacetic acid EDDA nitrilotriacetic acid NTA and iminodiacetic acid) of UO22+ and UO4 species of uranium VI is studied in aqueous solution (NaClO4 3M at 25 deg celcius). Structure in solution are proposed and discussed for mononuclear species. Only complexing kinetics (formation and acid hydrolysis) of UO4 with EDDA and NTA are studied by spectrophotometry (other reactions are too fast). Besides UO22+ complexes are formed with crown ethers I5C5 and I8C6 in aqueous solution (TEA ClO4 M/10 at 25 deg celcius. Complexes are probably stabilized by solvation. Results are confirmed by voltametry and reduction mechanisms of UO22+ and its complexes on mercury drop are proposed. 143 refs

  20. Toward Accurate Modeling of the Effect of Ion-Pair Formation on Solute Redox Potential.

    Science.gov (United States)

    Qu, Xiaohui; Persson, Kristin A

    2016-09-13

    A scheme to model the dependence of a solute redox potential on the supporting electrolyte is proposed, and the results are compared to experimental observations and other reported theoretical models. An improved agreement with experiment is exhibited if the effect of the supporting electrolyte on the redox potential is modeled through a concentration change induced via ion pair formation with the salt, rather than by only considering the direct impact on the redox potential of the solute itself. To exemplify the approach, the scheme is applied to the concentration-dependent redox potential of select molecules proposed for nonaqueous flow batteries. However, the methodology is general and enables rational computational electrolyte design through tuning of the operating window of electrochemical systems by shifting the redox potential of its solutes; including potentially both salts as well as redox active molecules. PMID:27500744

  1. Spherical and nonspherical models of primordial black hole formation: exact solutions

    CERN Document Server

    Harada, Tomohiro

    2015-01-01

    We construct spacetimes which provide spherical and nonspherical models of black hole formation in the flat Friedmann-Lemaitre-Robertson-Walker (FLRW) universe with the Lemaitre-Tolman-Bondi solution and the Szekeres quasispherical solution, respectively. These dust solutions may contain both shell-crossing and shell-focusing naked singularities. These singularities can be physically regarded as the breakdown of dust description, where strong pressure gradient force plays a role. We adopt the simultaneous big bang condition to extract a growing mode of adiabatic perturbation in the flat FLRW universe. If the density perturbation has a sufficiently homogeneous central region and a sufficiently sharp transition to the background FLRW universe, its central shell-focusing singularity is globally covered. If the density concentration is {\\it sufficiently large}, there appears no shell-crossing singularity and a black hole is formed. If the density concentration is {\\it not sufficiently large}, there appears shell-...

  2. Walk-Off-Induced Modulation Instability, Temporal Pattern Formation, and Frequency Comb Generation in Cavity-Enhanced Second-Harmonic Generation

    Science.gov (United States)

    Leo, F.; Hansson, T.; Ricciardi, I.; De Rosa, M.; Coen, S.; Wabnitz, S.; Erkintalo, M.

    2016-01-01

    We derive a time-domain mean-field equation to model the full temporal and spectral dynamics of light in singly resonant cavity-enhanced second-harmonic generation systems. We show that the temporal walk-off between the fundamental and the second-harmonic fields plays a decisive role under realistic conditions, giving rise to rich, previously unidentified nonlinear behavior. Through linear stability analysis and numerical simulations, we discover a new kind of quadratic modulation instability which leads to the formation of optical frequency combs and associated time-domain dissipative structures. Our numerical simulations show excellent agreement with recent experimental observations of frequency combs in quadratic nonlinear media [Phys. Rev. A 91, 063839 (2015)]. Thus, in addition to unveiling a new, experimentally accessible regime of nonlinear dynamics, our work enables predictive modeling of frequency comb generation in cavity-enhanced second-harmonic generation systems. We expect our findings to have wide impact on the study of temporal and spectral dynamics in a diverse range of dispersive, quadratically nonlinear resonators.

  3. Efficacy of antiadhesion barrier solution on periimplant capsule formation in a white rat model.

    Science.gov (United States)

    Lew, Dae Hyun; Yoon, Jung Ho; Hong, Jong Won; Tark, Kwan Chul

    2010-08-01

    Antiadhesive barrier solution (AABS) has been proven to prevent intraabdominal adhesion by reducing inflammation and fibrosis formation. Because this mechanism can also be applied to capsule formation after the breast implant insertion, we hypothesize that AABS can reduce capsular contraction and evaluate the efficacy of AABS on perisilastic implant capsule formation after submuscular insertion. A silicone block was inserted beneath the panniculus carnosus muscle in 10 rats. The experiment group received 0.1 mL of AABS (Guardix, Hanmi Medical Co.) instilled into the pocket, whereas the control group received 0.1 mL saline solution. Periimplant capsules were excised after 4 weeks and were evaluated for inflammatory cell count, capsular thickness, collagen pattern, and amount of myofibroblast. The inflammatory cell count and the capsular thickness were lower in the experiment group than in the control group (P < 0.05). The collagen pattern was loose and parallel in the experiment group, and the amount of myofibroblast was much less compared with the control group. AABS reduced the amount of inflammatory cells, myofibroblast, and capsular thickness. It also made the collagen fibers in the capsule loose and parallel. Therefore, AABS seemed to be effective in reducing the periimplant capsule formation. PMID:20606576

  4. Formation of fine solid particles from aqueous solutions of sodium chloropalladate by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Studies have been carried out on the radiation chemical formation of palladium fine particles in argon saturated aqueous solutions of sodium chloropalladate without organic stabilizer. The solutions were irradiated with gamma-rays from a cobalt gamma-ray source and the irradiated solutions were subjected to the dynamic light scattering analysis for the particle diameter measurements, and to the UV-visible optical absorption spectroscopy for the measurements of turbidity (absorption at 700 nm) and remaining chloropalladate ion concentrations in the solution. In the solution of pH = 1.95 by HCl, the turbidity increased after the irradiation and then decreased with time. The concentration of remaining palladate ion in the solution decreased by the irradiation, but it gradually increased with time after the irradiation. These phenomena were qualitatively explained by the reaction scheme in that a precursor to the solid particles still exists in the solution after the irradiation was terminated, and that intermediates including the precursor reacted with chloride ion to re-form chloropalladate ions. The average diameter of the particles after the irradiation was ca. 20 nm and it increased with time to 40 nm at 2.75 kGy, and to 80 nm at 8.25 kGy absorption of radiation. The solution of pH = 0.65 by HCl was found to give lower yields of particles than those observed for the solution of pH = 1.95, and to give the particles of diameters about 150-200 nm. In the solution containing HClO4 instead of HCl, palladium particles were also formed by the irradiation, whereas no backward reaction after the irradiation was observed due to the low concentration of chloride ion in the solution. The average diameter of the particles after the irradiation was about 300 nm and increased with time after the irradiation to a final values which was found to depend on pH of the solution and dose. (author)

  5. Interaction mode and nanoparticle formation of bovine serum albumin and anthocyanin in three buffer solutions

    International Nuclear Information System (INIS)

    Investigation of interaction mode of bovine serum albumin (BSA) and anthocyanin (ACN) in different solutions will help us understand the interaction mechanism and functional change of bioactive small molecule and biomacromolecule. This study investigated the binding mode, including binding constant, number of binding sites, binding force of BSA and ACN interaction in three buffer solutions of phosphate (PBS), sodium chloride (NaCl), and PBS-NaCl, using fluorescence spectroscopy and synchronous fluorescence spectroscopy. Formation and characteristics of BSA–ACN complex were also investigated using dynamic light scattering (DLS) and transmission electron microscopy (TEM). The results showed that ACN could interact with BSA at both tyrosine (Tyr) and tryptophan (Trp) residues through both hydrogen bonds and van der Waals force, and the same binding mode was seen in dH2O and three buffer solutions. The value of binding constant K was decreased as the temperature increased from 298 K to 308 K, and the decreasing degree was in the order of dH2O (9.0×104)>NaCl (2.64×104)/PBS (2.37×104)>PBS-NaCl (0.88×104), which was inversely correlated with the ionic strength of the buffer solutions of PBS-NaCl>NaCl>PBS. It indicated that stability of BSA–ACN complex was affected most in dH2O than in three buffer solutions. The BSA and ACN interaction led to formation of BSA–ACN nanoparticles. The sizes of BSA–ACN nanoparticles in dH2O were smaller than that in three buffer solutions, which correlated with stronger binding force between BSA and ACN in dH2O than in three buffer solutions at room temperature (25 °C, 298 K). - Highlights: • We report the influences of four solutions on the BSA–ACN interaction. • We report the relationship between BSA–ACN interaction and particle size of complex. • The stability of BSA–ACN complex was affected most in dH2O than in buffer solutions

  6. Interaction mode and nanoparticle formation of bovine serum albumin and anthocyanin in three buffer solutions

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Rui; Dong, Xueyan; Song, Lanlan; Jing, Hao, E-mail: hao.haojing@gmail.com

    2014-11-15

    Investigation of interaction mode of bovine serum albumin (BSA) and anthocyanin (ACN) in different solutions will help us understand the interaction mechanism and functional change of bioactive small molecule and biomacromolecule. This study investigated the binding mode, including binding constant, number of binding sites, binding force of BSA and ACN interaction in three buffer solutions of phosphate (PBS), sodium chloride (NaCl), and PBS-NaCl, using fluorescence spectroscopy and synchronous fluorescence spectroscopy. Formation and characteristics of BSA–ACN complex were also investigated using dynamic light scattering (DLS) and transmission electron microscopy (TEM). The results showed that ACN could interact with BSA at both tyrosine (Tyr) and tryptophan (Trp) residues through both hydrogen bonds and van der Waals force, and the same binding mode was seen in dH{sub 2}O and three buffer solutions. The value of binding constant K was decreased as the temperature increased from 298 K to 308 K, and the decreasing degree was in the order of dH{sub 2}O (9.0×10{sup 4})>NaCl (2.64×10{sup 4})/PBS (2.37×10{sup 4})>PBS-NaCl (0.88×10{sup 4}), which was inversely correlated with the ionic strength of the buffer solutions of PBS-NaCl>NaCl>PBS. It indicated that stability of BSA–ACN complex was affected most in dH{sub 2}O than in three buffer solutions. The BSA and ACN interaction led to formation of BSA–ACN nanoparticles. The sizes of BSA–ACN nanoparticles in dH{sub 2}O were smaller than that in three buffer solutions, which correlated with stronger binding force between BSA and ACN in dH{sub 2}O than in three buffer solutions at room temperature (25 °C, 298 K). - Highlights: • We report the influences of four solutions on the BSA–ACN interaction. • We report the relationship between BSA–ACN interaction and particle size of complex. • The stability of BSA–ACN complex was affected most in dH{sub 2}O than in buffer solutions.

  7. Oxide film formation on a microcrystalline Al alloy at various temperatures in neutral borate solution

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, S.C.; Birss, V.I. [Univ. of Calgary, Alberta (Canada). Dept. of Chemistry

    1997-10-01

    FVS0812 is a rapidly solidified Al alloy consisting of an intermetallic (dispersoid) phase, containing Al, Fe, V, and Si, surrounded by a predominantly Al matrix. The electrochemical behavior and the oxide film structure of FVS0812 were compared to that of its two phases, as well as pure Al, in neutral borate solution at a range of temperatures. While in acidic solution, FVS0812 is unable to form an adherent, thick, porous oxide film, in 60 C neutral solution, stable, although substantially thinner, porous oxides are formed on Al, FVS0812, and the matrix. In contrast to its dissolution in acidic medium, the dispersoid phase is retained within the porous film formed on the alloy in neutral solution. However, the dispersoid phase also causes the formation of a somewhat contorted porous oxide structure. Impedance measurements suggest that solution penetration into fine flaws in the barrier oxide at the barrier/porous oxide interface, a phenomenon exacerbated by increased temperature and time at applied potentials, is more prevalent for FVS0812 than for Al and the matrix.

  8. AGN jet power, formation of X-ray cavities, and FR I/II dichotomy in galaxy clusters

    Science.gov (United States)

    Fujita, Yutaka; Kawakatu, Nozomu; Shlosman, Isaac

    2016-04-01

    We investigate the ability of jets in active galactic nuclei to break out of the ambient gas with sufficiently large advance velocities. Using observationally estimated jet power, we analyze 28 bright elliptical galaxies in nearby galaxy clusters. Because the gas density profiles in the innermost regions of galaxies have not been resolved so far, we consider two extreme cases for temperature and density profiles. We also follow two types of evolution for the jet cocoons: being driven by the pressure inside the cocoon [Fanaroff-Riley (FR) type I], and being driven by the jet momentum (FR type II). Our main result is that regardless of the assumed form of the density profiles, jets with observed powers of ≲1044 erg s-1 are not powerful enough to evolve as FR II sources. Instead, they evolve as FR I sources and appear to be decelerated below the buoyant velocities of the cocoons when jets were propagating through the central dense regions of the host galaxies. This explains why FR I sources are more frequent than FR II sources in clusters. Furthermore, we predict the sizes of X-ray cavities from the observed jet powers and compare them with the observed ones-they are consistent within a factor of two if the FR I type evolution is realized. Finally, we find that the jets with a power ≳1044 erg s-1 are less affected by the ambient medium, and some of them, but not all, could serve as precursors of the FR II sources.

  9. Slow light, open-cavity formation, and large longitudinal electric field on a slab waveguide made of indefinite permittivity metamaterials

    Science.gov (United States)

    Lu, W. T.; Sridhar, S.

    2010-07-01

    The optical properties of slab waveguides made of indefinite permittivity (ɛ) materials (IEMs) are considered. In this medium, the real part of the transverse permittivity is negative while that of the longitudinal permittivity is positive. At any given frequency, the IEM waveguide supports an infinite number of transverse magnetic (TM) eigenmodes. For a slab waveguide with a fixed thickness, at most only one TM mode is forward wave. The remainder are backward waves which can have a very large phase index. At a critical thickness, the waveguide supports degenerate forward- and backward-wave modes with zero group velocity if loss is absent. Above the critical thickness, the waveguide supports complex-conjugate decay modes instead of propagating modes. The presence of loss in IEMs will lift the TM mode degeneracy, resulting in modes with finite group velocity. A feasible realization is proposed. The performance of the IEM waveguide is analyzed and possible applications are discussed, which are supported by numerical calculations. These slab waveguides can be used to make optical delay lines in optical buffers to slow down and trap light, to form open cavities, to generate strong longitudinal electric fields, and as phase shifters in optical integrated circuits. Although the presence of loss will hinder these applications, gain can be introduced to compensate the loss and enhance the performance.

  10. Dipole solution and angular-momentum minimization for two-satellite electromagnetic formation flight

    Science.gov (United States)

    Huang, Xian-lin; Zhang, Chun; Ban, Xiao-jun

    2016-02-01

    Electromagnetic formation flight is very attractive for no fuel expenditure, and may become an alternative to traditional propellant-based spacecraft formation flying. When electromagnetic forces are used to determine relative satellite positions, electromagnetic torques are created simultaneously and result in angular-momentum buildup. This paper investigates dipole computation and angular-momentum minimization for a two-satellite formation. Instead of using dipole vectors, a group of parameters are introduced to represent the relation between the electromagnetic force and torque. These parameters enable a certain freedom of allocating electromagnetic torques, and help find an analytical dipole solution to minimize total electromagnetic torque action. It is shown that an electromagnetic force is unconstrained only if associated torque ratios ranges from 0.5 to 2. The impact of formation configuration and control is also investigated. Torque-free formations are obtained where electromagnetic torques can be simply removed. A parameter optimization model is derived under the framework of sliding mode control to minimize angular-momentum buildup. Simulation results demonstrate the effect of the proposed angular-momentum minimization method.

  11. The formation of amino acid and dipeptide complexes with α-cyclodextrin and cucurbit[6]uril in aqueous solutions studied by titration calorimetry

    International Nuclear Information System (INIS)

    The complex stabilities and the thermodynamic data for the complexation of α-cyclodextrin and cucurbit[6]uril with some amino acids (glycine, L-alanine, L-valine, L-phenylalanine, 6-amino hexanoic acid, 8-amino octanoic acid, 11-amino undecanoic acid) and dipeptides (glycyl-glycine, glycyl-L-valine, glycyl-L-leucine and glycyl-L-phenylalanine) have been determined in aqueous solution by calorimetric titrations. The complex formation with α-cyclodextrin is mainly favoured by entropic contributions due to the release of water molecules from the cavity of the ligand. The values of the reaction enthalpies are small with the exception of 11-amino undecanoic acid. In case of the ligand cucurbit[6]uril, ion-dipole interactions between the protonated amino groups of the amino acids and the carbonyl groups take place. By steric reasons these interactions are lowered for native amino acids because the polar carboxylic groups are always located outside the hydrophobic cavity of cucurbit[6]uril. The complexes of both ligands with dipeptides in water are characterised by hydrophobic interactions and in case of cucurbit[6]uril by additional ion-dipole interactions

  12. Shear thickening and onion formation of non-ionic surfactant solution and the effect of charge

    International Nuclear Information System (INIS)

    A shear-induced lamellar to onion transition of a surfactant solution has attracted considerable attention in these decades. Diat and Roux have shown that shear flow induces a transformation from planer lamellar structure to multilamellar vesicles (onions) with a polyhedral shape, which fill all the space without excess water and lead shear thickening. In a nonionic surfactant aqueous solution, pentaethylene glycol monododecyl ether (C12E5) and D2O, onion formation associated with shear thickening is observed in 40 wt% C12E5 solution at T=55° C Effects of charge on the nonionic surfactant mixture were investigated by adding ionic surfactant and onion structure is induced by the suppression of Helfrich undulation of surfactant membranes. [3] Here we investigated the rheological behavior of a dilute solution of C12E5 (10 wt%) and D2O and the effect of charge. We have already shown that a disordered structure of C12E5 and D2O at T=59 °C transforms to an ordered lamellar structure by adding an antagonistic salt such as sodium tetraphenylborate (NaBPh4). An electrostatic interaction between surfactant membranes caused by a heterogeneous distribution of anions and cations originates the transformation as the effect of adding ionic surfactant sodium dodecyl sulfate (SDS). Figure 1 shows molar ratio between SDS and C12E5, S, dependence of viscosity as a function of shear rate. It is clear that shear thickening is observed for all the samples measured including SDS and a shoulder at 2 s-1 is observed for the sample without charged molecules. The present SANS experiment confirmed that the lamellar layers are oriented parallel to the flow direction at low shear rate, while onion structure is formed as evident by isotropic scattering pattern, which is eventually broken by further increase of shear rate. This is the first evidence of the shear thickening and the onion formation in the dilute solution of nonionic surfactant.

  13. Dynamics of Magnesite Formation at Low Temperature and High pCO2 in Aqueous Solution.

    Science.gov (United States)

    Qafoku, Odeta; Dixon, David A; Rosso, Kevin M; Schaef, Herbert T; Bowden, Mark E; Arey, Bruce W; Felmy, Andrew R

    2015-09-01

    Magnesite precipitation from aqueous solution, despite conditions of supersaturation, is kinetically hindered at low temperatures for reasons that remain poorly understood. The present study examines the products of Mg(OH)2 reaction in solutions saturated with supercritical CO2 at high pressures (90 and 110 atm) and low temperatures (35 and 50 °C). Solids characterization combined with in situ solution analysis reveal that the first reaction products are the hydrated carbonates hydromagnesite and nesquehonite, appearing simultaneously with brucite dissolution. Magnesite is not observed until it comprises a minor product at 7 days reaction at 50 °C. Complete transition to magnesite as the sole product at 35 °C (135 days) and at a faster rate at 50 °C (56 days) occurs as the hydrated carbonates slowly dissolve under the slightly acidic conditions generated at high pCO2. Such a reaction progression at high pCO2 suggests that over long term the hydrated Mg-carbonates functioned as intermediates in magnesite formation. These findings highlight the importance of developing a better understanding of the processes expected to occur during CO2 storage. They also support the importance of integrating magnesite as an equilibrium phase in reactive transport calculations of the effects of CO2 sequestration on geological formations at long time scale. PMID:26200317

  14. Eradication of colon cancer cells before tumour formation in the peritoneal cavity of mice treated with intraperitoneal Re-186 radioimmunotherapy

    International Nuclear Information System (INIS)

    A treatment adjuvant to surgical resection of the primary lesion has been proven to be beneficial in improving the prognosis of patients with high risks of peritoneal dissemination of colon cancer. This study was performed to determine the comparative efficacy of intraperitoneal radioimmunotherapy (RIT) using Re-186 or I-131 labeled murine antibodies in the extermination of cancer cells. A murine anti-colorectal IgG1, A7 monoclonal antibody, was radio-labeled either with I-131 (by the chloramine-T method) or Re-186 (by the MAG3 pre-chelated method). A total number of 16 mice were subjected to RIT with Re-186 A7 (N=8) or I-131 A7 (N=8) at equitoxic doses in Balb/c bu/nu mice 10 min after intraperitoneal injection of LS180 human colon cancer cells. A third group of mice were subjected to chemotherapy with 5-fluorouracil at 30 mg/kg for 4 consecutive days following the intraperitoneal injection of the same LS180 human colon cancer cells. There were 19 mice in the control group who were not subjected to any form of therapy. The results revealed that the mean survival of mice in the control (N-19), I-131 A7 RIT (N=8) and Chemotherapy (N=6) groups were 33.8 ± 1.0, 80.1 ± 2.5 and 49.3 ± 5.3 days respectively. The eight mice who were subjected to Re-186 A7 RIT showed much better survival compared to the other groups. Two of the eight mice from this group died at 105 and 111 days following Re-186 A7 RIT. Other six mice were sacrificed at 172 days, and autopsy revealed no macroscopic peritoneal tumor growth. Based on this pilot study we concluded that individual tumor cells in the peritoneal cavity would be effectively exterminated by intraperitoneal RIT with Re-186 A7. (author)

  15. Barium and strontium sulfate solid solution formation in relation to North Sea scaling problems

    International Nuclear Information System (INIS)

    This paper presents the results of laboratory experiments carried out to investigate barium sulphate and strontium sulphate solid solution formation in multi-pressure tapped cores. Two brines, one barium and strontium rich and the other sulphate rich, were mixed in a core plug. Pressure differentials were measured and the changing permeability distribution along the length of the core calculated. The morphology and chemical analysis of scaling crystals are presented based on Scanning electron Microsocpy (SEM) and Energy Dispersive X-ray Analysis (EDAX). The results show the large extent of permeability damage caused by (Ba, SR) SO/sub 4/ solid solution depositing on the rock pore surface. The rock permeability decline and morphology and size of the scaling crystals indicate the influence of the supersaturations of BaSO/sub 4/ and SrSO/sub 4/ as well as the concentration ratio of barium ions to strontium ions

  16. The sealing of excavation damaged zones in salt formations using sodium silicate solutions

    Energy Technology Data Exchange (ETDEWEB)

    Engelhardt, Hans-Joachim; Schmidt, Holger; Borstel, Lieselotte von [DBE TECHNOLOGY GmbH, Peine (Germany). Dept. of Repository Safety

    2015-07-01

    Since many decades, pressure grouting is an effective technique of civil engineering for sealing and stabilization purposes. Due to the potential contamination of fluids, grouting is of particular importance in repositories of radioactive waste. Traditional grouts for the sealing of fine fractures are sodium silicate solutions. Laboratory and field investigations prove that the particle-free solutions can be used to permanently seal excavation damaged zones (EDZ) in salt formations, because the solid reaction products are inert or almost insoluble. EDZ permeabilities of 10{sup -17} m{sup 2} can be achieved and were determined on the basis of the injection pressures and flow rates. High grouting pressures were realized as local test loadings. Laboratory tests show the fixation of Co{sup 2+}, Ni{sup 2+}, Sr{sup 2+}, Ba{sup 2+}, [UO{sub 2}]{sup 2+} and illustrate that sodium silicates may act additionally as a chemical barrier.

  17. Substitutional solute atom-vacancy complex formation in proton-irradiated Zirlo

    International Nuclear Information System (INIS)

    The role of substitutional alloying elements on the recovery processes associated with proton-induced defects in a new zirconium-based alloy (known as Zirlo) is investigated by positron annihilation studies. We observed that the atoms of the alloying elements when knocked out by protons from complexes with the vacancies generated by the removal of host Zr atoms. The formation of the solute atom-vacancy complexes is favoured by the fact that these atoms can migrate only substitutionally in the close-packed crystal structure. With increasing dose of irradiation, the usual defect agglomeration dominates but the growth of vacancy clusters is restricted by the octahedral oxygen atoms which diffuse to an appreciable number of Zr vacancies. Isochronal annealing of the defects took place in three stages and are respectively identified as the annealing of dislocation/vacancy loops, an antirecovery stage due to the dissociation of the solute atom-vacancy complexes and the final annealing of vacancy clusters. (author)

  18. The sealing of excavation damaged zones in salt formations using sodium silicate solutions

    International Nuclear Information System (INIS)

    Since many decades, pressure grouting is an effective technique of civil engineering for sealing and stabilization purposes. Due to the potential contamination of fluids, grouting is of particular importance in repositories of radioactive waste. Traditional grouts for the sealing of fine fractures are sodium silicate solutions. Laboratory and field investigations prove that the particle-free solutions can be used to permanently seal excavation damaged zones (EDZ) in salt formations, because the solid reaction products are inert or almost insoluble. EDZ permeabilities of 10-17 m2 can be achieved and were determined on the basis of the injection pressures and flow rates. High grouting pressures were realized as local test loadings. Laboratory tests show the fixation of Co2+, Ni2+, Sr2+, Ba2+, [UO2]2+ and illustrate that sodium silicates may act additionally as a chemical barrier.

  19. Formation of metal and dielectric liners using a solution process for deep trench capacitors.

    Science.gov (United States)

    Ham, Yong-Hyun; Kim, Dong-Pyo; Baek, Kyu-Ha; Park, Kun-Sik; Kim, Moonkeun; Kwon, Kwang-Ho; Shin, Hong-Sik; Lee, Kijun; Do, Lee-Mi

    2012-07-01

    We demonstrated the feasibility of metal and dielectric liners using a solution process for deep trench capacitor application. The deep Si trench via with size of 10.3 microm and depth of 71 microm were fabricated by Bosch process in deep reactive ion etch (DRIE) system. The aspect ratio was about 7. Then, nano-Ag ink and poly(4-vinylphenol) (PVPh) were used to form metal and dielectric liners, respectively. The thicknesses of the Ag and PVPh liners were about 144 and 830 nm, respectively. When the curing temperature of Ag film increased from 120 to 150 degrees C, the sheet resistance decreased rapidly from 2.47 to 0.72 Omega/sq and then slightly decreased to 0.6 Omega/sq with further increasing the curing temperature beyond 150 degrees C. The proposed liner formation method using solution process is a simple and cost effective process for the high capacity of deep trench capacitor. PMID:22966677

  20. Dithiothreitol-induced formation of thymine glycol in heated solutions of thymine or DNA

    International Nuclear Information System (INIS)

    Although it has been known for a number of years that autoxidation of thiols in solution generates hydroxyl radical ( . OH) through the iron-catalized and superoxide ion-dependent conversion of hydrogen peroxide, the magnitude of these effects on DNA and its constituent bases has yet to be determined. The authors measured thymine glycol (TG), a major product of thymine- . OH reactions, in phosphate-buffered (10 mM, pH 7) solutions of thymine and dithiothreitol (DTT, 0.01-20 mM) and in similar solutions containing single-stranded or double-stranded DNA. TG is readily produced in heated (450C) or refrigerated (50C) thymine-DTT mixtures. After 2 hr of heating (450C), TG yield is equivalent to that produced in thymine solutions irradiated to 50 Gy (in O/sub 2/). Disodium-EDTA (0.5 mM) produced a 7-fold increase in TG formation whereas diethylenetriaminepentaacetic acid (DTPA, 1 mM) inhibited TG production. The actions of these chelators strongly suggest that iron (present as a contaminant in the phosphate buffer) is required for the production of TG. Preliminary results show that TG yields in DTT-treated (10 mM) and heated DNA (450 x 4 hr) are reduced in comparison to the yields obtained with free thymine. This work provides additional - molecular-level - evidence that thiol autoxidation might explain the enhanced toxicity of thiols in heated cells

  1. Lack of Evidence for Prenucleation Aggregate Formation in Lysozyme Crystal Growth Solutions

    Science.gov (United States)

    Muschol, Martin; Rosenberger, Franz

    1996-01-01

    There have been numerous claims of large concentrations of prenucleation aggregates in supersaturated as well as undersaturated lysozyme solutions at high salt concentrations. The presence of these aggregates was derived from measurements of the light or neutron scattering intensity, ultracentrifugation and dialysis behavior, as well as over-simplified crystal growth kinetics considerations. In all these interpretations it has been assumed that lysozyme solutions are either ideal or that protein interactions are independent of salt concentration. Contrary to these presumptions, our static and dynamic light scattering experiments provide evidence that lysozyme forms highly non-ideal, strongly interacting solutions. At low salt concentrations, the scattering intensities fall well below the values expected for an ideal, monomeric solution at the same protein concentration, while diffusivities increase with increasing protein concentration. Upon increase in salt concentration, these trends are eventually reversed. This enhancement in scattering intensity and decrease in diffusivity was widely interpreted as sign of aggregate formation. Yet, a quantitative interpretation of the scattering behavior over the whole salt concentration range can only be given in terms of a transition from net repulsion to net attraction between lysozyme monomers. Increased salt screening of the electrostatic repulsion among the protein macro-ions, together with attractive protein interactions, such as van der Waals, hydrophobic and hydration forces, provide an unambiguous mechanism for the observed transition and a more physical interpretation of the various observations.

  2. Formation of 3He droplets in dilute 3He-4He solid solutions

    Science.gov (United States)

    Huan, Chao; Candela, Don; Kim, Sung; Yin, Liang; Xia, Jiang-Sheng; Sullivan, Neil

    2015-03-01

    We review the different stages of the formation of 3He droplets in dilute solid 3He-4He solutions. The studies are interesting because the phase separation in isotopic helium mixtures is a first-order transition with a conserved order parameter. The rate of growth of the droplets as observed in NMR studies is compared with the rates expected for homogeneous nucleation followed by a period of coarsening known as Ostwald ripening. Work suported by the National Science Foundation - DMR-1303599 and DMR- 1157490 (National High Magnetic Field Laboratory).

  3. Mechanism of Cl2- formation during pulsed radiolysis of neutral aqueous solutions of alkali metal chlorides

    International Nuclear Information System (INIS)

    The kinetics of accumulation and destruction of Cl2- in pulsed radiolysis of neutral aqueous solutions of KCl has been investigated. It is assumed that the process mechanism includes the reactions [H3O+...OH]+Cl- → Cl+2H2O (1). It is shown that reaction (2) is the rate-limiting stage of formation of Cl2-. Using a computer the authors calculated the rate constants of reactions (2) and (3), which were found to be equal to 7.6x105 l/molxsec and 1.7x1010 l/molxsec, respectively

  4. Oxygen formation in gamma-ray irradiation of Fe2+ -Cu2+ solutions

    DEFF Research Database (Denmark)

    Bjergbakke, Erling; Hart, E.J.

    1971-01-01

    The mechanism of O2 formation has been studied in 60 Co γ-ray-irradiated Fe(II) + Cu(II) solutions at 0.01 N HClO4 and at 0.01, 0.08, and 0.80 N H2 SO4. In the H2 SO4 system, ${\\rm G}({\\rm O}_{2})$ rises to plateau levels near 0.02 as the ${\\rm CuSO}_{4}/{\\rm FeSO}_{4}$ ratio increases. The plateau...

  5. Formation of deep destruction products during indirect radiation action on alcohols in aqueous solutions

    International Nuclear Information System (INIS)

    Formation of deep destruction products with the scission of C-C and C-O bonds during γ-radiolysis of the iso-propanol-water system in neutral and alkaline solutions depending on the electron part of alcohol is studied. Considerable positive deviations of the yield of certain products from additivity rule are detected. It is shown that in the presence of alkali the yields of all the products increase. Similar effects are established during radiolysis of the tert.- butanol-water system. The results obtained are compared with the data known for binary mixtures of methanol, ethanol and n-propanol with water

  6. Intertemporal Asset Allocation with Habit Formation in Preferences: An Approximate Analytical Solution

    DEFF Research Database (Denmark)

    Pedersen, Thomas Quistgaard

    In this paper we derive an approximate analytical solution to the optimal con- sumption and portfolio choice problem of an infinitely-lived investor with power utility defined over the difference between consumption and an external habit. The investor is assumed to have access to two tradable...... introduces an additional component that works as a hedge against changes in the investor's habit level. In an empirical application, we calibrate the model to U.S. data and show that habit formation has significant effects on both the optimal consumption and portfolio choice compared to a standard CRRA...

  7. Oligo-lysine Induced Formation of Silica Particles in Neutral Silicate Solution

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Oligo-(lysine)n (n = 1-4) containing different numbers of lysine residues was used to induce the condensation of silicic acid to form silica particles in neutral silicate solution. It was found that the condensation rate and the formation of silica particles are dependent on the number of lysine residues in an oligo-lysine. Oligo-lysine with more lysine residues can link more silicic acid together to form a matrix that promotes the effective aggregation of the condensed silica pieces to form large silica particles.

  8. Standard molar enthalpy of formation of Pr6UO12 by acid solution calorimetry

    International Nuclear Information System (INIS)

    Rare earth constitute major fraction of the fission product and reacts with the fuel during irradiation. Under transient conditions, compounds of formula, RE6UO12 (RE = Rare earths) with rhombohedral crystal structure are formed. The standard enthalpy of formation of La6UO12 and Nd6UO12 has been reported in our earlier publication. As there are no reported data on that of Pr6UO12, the experiments pertaining to the same was carried out in the present work. The experiments were carried out by using the indigenously developed semi-adiabatic isoperibol solution calorimeter

  9. Montmorillonite catalysis of RNA oligomer formation in aqueous solution. A model for the prebiotic formation of RNA

    Science.gov (United States)

    Ferris, J. P.; Ertem, G.

    1993-01-01

    Oligomers of adenylic acid of up to the 11-mer in length are formed by the reaction of the phosphorimidazolide of adenosine (ImpA) in pH 8 aqueous solution at room temperature in the presence of Na(+)-montmorillonite. These oligomers are joined by phosphodiester bonds in which the 3',5'-linkage predominates over the 2',5'-linkage by a 2:1 ratio. Reaction of a 9:1 mixture of ImpA, A5'ppA results in the formation of oligomers with a 3:1 ratio of 3',5'- to 2',5'-linked phosphodiester bonds. A high proportion of these oligomers contain the A5'ppA grouping. A5'ppA reacts much more rapidly with ImpA than does 5'-ADP (ppA) or 5'-ATP (pppA). The exchangeable cation associated with the montmorillonite effects the observed catalysis with Li+, Na+, NH4+, and Ca2+ being the more effective while Mg2+ and Al3+ are almost ineffective catalysts. 2',5'-Linked oligomers, up to the tetramer in length, are formed using UO2(2+)-montmorillonite. The structure analysis of individual oligomer fractions was performed by selective enzymatic and KOH hydrolytic studies followed by HPLC analysis of the reaction products. It is concluded from the composition of the oligomers that the rate of addition ImpA to a 3'-terminus containing a 2',5'-linkage is slower than the addition to a nucleoside joined by a 3',5'-linked phosphodiester bond. The potential importance of mineral catalysis of the formation of RNA and other oligomers on primitive Earth is discussed.

  10. Study of the sintering process and the formation of a (Th, U) O2 solid solution

    International Nuclear Information System (INIS)

    The effect of some variables in the (Th, U) O2 sintering process and solid solution formation was studied. ThO2, U3O8 and UO2 powder were prepared. The ThO2 powders were obtained by calcination of thorium at 500 and 750 deg C; the U3O8 powders were derived from the calcination of ADU at 660 and 750 deg C; the UO2 powder were prepared from ADU and from ATCU. The different characteristics of these materials were determined by measurements of surface area, by scanning electron microscopy, tap density tests, X-ray diffractometry and by measurements of the O/U ratios. The oxide mixtures were chosen in order to produce a final composition with 10 w/o of UO2. A mixture of thorium oxalate and ADU was also prepared by calcining these salts in air at 700 deg C, in order to obtain certain amount of solid solution prior to sintering. The sintering operations were developed in an argon atmosphere at temperatures between 1400 and 1700 deg C, during interval varying from 1 to 4 hours. The effect of the mixture characteristics on the sintering process and solid solution formation were studied considering the results of densification, microstructure development and X-ray diffractometry. The ThO2 powder characteristics have a main effect on the mixtures compactability and sinterability, the higher calcining temperatures increasing the green density, but decreasing the final density of the sintered pellets. In the sintering of mixtures containing U3O3, this oxide is reduced to UO2 and it is possible to obtain pellets with density and microstructures similar to those produced from mixtures containing UO2. But if oxygen in excess is present during sintering, the process is affected, occurring exaggerated grain growth. The densification results were related to the Coble's kinetics equation for second stage of sintering, valid for bulk diffusion, grain boundary acting as vacancy sinks. The sintering activation energy is independent from the powder starting characteristics, its value

  11. Laser cavity modelling

    OpenAIRE

    Damakoa, I.; Audounet, J.; Bouyssou, G.; Vassilieff, G.

    1993-01-01

    Two approachs of modelling nonhomogeneous cavity laser are presented. They are based on the beam propagation method which allows the use of fast Fourier transform (FFT). The resulting procedures provide selfconsistent solutions to the Maxwell and diffusion equations. Results are given to illustrate the two methods.


  12. Orientation of the peptide formation of N-phosphoryl amino acids in solution

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The peptide formation of N-phosphoryl aminoacids with amino acids proceeds in aqueous solution withoutany coupling reagents. After being separated in sephadex gelcolumn, the phosphoryl dipeptides were analyzed by theelectrospray ionization tandem mass spectrometry (ESIMS/MS). The result demonstrates that phosphoryl dipeptides were detected in all the reaction systems. It is found that theformation of N-phosphoryl dipeptides is oriented: theN-terminal amino acid residues of the N-phosphoryl dipep-tides are from N-phosphoryl amino acids, and the peptideelongation happened at the C-terminal. Only (-dipeptide, no(-dipeptide, is formed in the N-phosphoryl dipeptides,showing that ?-carboxylic group is activated selectively byN-phosphorylation. Theoretical calculation shows that the peptide formation of N-phosphoryl amino acids might hap-pen through a penta-coordinate carboxylic-phosphoric in-termediate in solution. These results might give some clues tothe study on the origin of proteins and protein biosynthesis.

  13. Cadmium(II) N-acetylcysteine complex formation in aqueous solution.

    Science.gov (United States)

    Jalilehvand, Farideh; Amini, Zahra; Parmar, Karnjit; Kang, Eun Young

    2011-12-21

    The complex formation between Cd(II) ions and N-acetylcysteine (H(2)NAC) in aqueous solution was investigated using Cd K- and L(3)-edge X-ray absorption and (113)Cd NMR spectroscopic techniques. Two series of 0.1 M Cd(II) solutions with the total N-acetylcysteine concentration c(H2NAC) varied between 0.2-2 M were studied at pH 7.5 and 11.0, respectively. At pH = 11 a novel mononuclear [Cd(NAC)(4)](6-) complex with the average Cd-S distance 2.53(2) Å and the chemical shift δ((113)Cd) = 677 ppm was found to dominate at a concentration of the free deprotonated ligand [NAC(2-)] > 0.1 M, consistent with our previous reports on cadmium tetrathiolate complex formation with cysteine and glutathione. At pH 7.5 much higher ligand excess ([HNAC(-)] > 0.6 M) is required to make this tetrathiolate complex the major species. The (113)Cd NMR spectrum of a solution containing c(Cd(II)) = 0.5 M and c(H2NAC) = 1.0 M measured at 288 K showed three broad signals at 421, 583 and 642 ppm, which can be attributed to CdS(3)O(3), CdS(3)O and CdS(4) coordination sites, respectively, in oligomeric Cd(II)-NAC species with single thiolate bridges between the cadmium ions. PMID:22012146

  14. Liquid-Liquid Phase Separation in Supersaturated Lysozyme Solutions and Associated Precipitate Formation/Crystallization

    Science.gov (United States)

    Muschol, Martin; Rosenberger, Franz

    1997-01-01

    Using cloud point determinations, the phase boundaries (binodals) for metastable liquid-liquid (L-L) separation in supersaturated hen egg white lysozyme solutions with 3%, 5%, and 7% (wlv) NaCl at pH= 4.5 and protein concentrations c between 40 and 400 mg/ml were determined. The critical temperature for the binodal increased approximately linearly with salt concentration. The coexisting liquid phases both remained supersaturated but differed widely in protein concentration. No salt repartitioning was observed between the initial and the two separated liquid phases. After the L-L separation, due to the presence of the high protein concentration phase, crystallization occurred much more rapidly than in the initial solution. At high initial protein concentrations, a metastable gel phase formed at temperatures above the liquid binodal. Both crystal nucleation and gel formation were accelerated in samples that had been cycled through the binodal. Solutions in the gel and L-L regions yielded various types of precipitates. Based on theoretical considerations, previous observations with other proteins, and our experimental results with lysozyme, a generic phase diagram for globular proteins is put forth. A limited region in the (T,c) plane favorable for the growth of protein single crystals is delineated.

  15. Complex formation between neptunium(V) and various thiosemicarbazide derivatives in aqueous solution

    International Nuclear Information System (INIS)

    Complex formation between neptunium(V) and various thiosemicarbazide derivatives in solution has been studied spectrophotometrically in the pH range 4-10. Stepwise formation of three types of complexes, with composition NpO2HA, NpO2A-, and NpOHA2-, has been demonstrated with salicylaldehyde thiosemicarbazone (H2L) and salicylaldehyde S-methyl-isothiosemicarbazone (H2Q) at t = 25 +/- 10C and μ = 0.05. The logarithmic stability constants of the first two complexes are 5.14 +/- 0.06, 11.85 +/- 0.04 and 8.42 +/- 0.09, 13.33 +/- 0.015 for H2L and H2Q, respectively; equilibrium constants for the formation of hydroxo complexes of the form NpO2OHL2- and NpO2OHQ2- were also determined, and found to be equal to (2.23 +/-0.37) x 10-5 and (5.02 +/- 0.9) x 10-5, respectively. In the case of S-methyl-N1,N4-bis(salicylidene)isothiosemicarbazide (H2Z), only one type of complex is formed under these experimental conditions, namely, NpO2Z-, with a logarithmic stability constant of 4.78 +/- 0.03. Dissociation constants for H2Q and H2Z were also determined

  16. Investigation into formation of nanoparticles of tetravalent neptunium in slightly alkaline aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Husar, Richard

    2015-08-20

    Considering the worldwide growing discharge of minor actinides and the current need for geological disposal facilities for radioactive waste, this work provides a contribution to the safety case concerning Np transport if it would be released from deep repository sites and moving from alkaline cement conditions (near-field) to more neutral environmental conditions (far-field). The reducing conditions in a nuclear waste repository render neptunium tetravalent, which is assumed to be immobile in aqueous environment due to the low solubility solution of Np(IV). For tetravalent actinide nuclides, the most significant transport should occur via colloidal particles. This work demonstrates the formation of intrinsic neptunium dioxide nanocrystals and amorphous Np(IV) silica colloids under environmentally relevant conditions. The dissociation of the initial soluble Np(IV) complex (i.e. [Np(IV)(CO{sub 3}){sub 5}]{sup 6-}) induces the intrinsic formation of nanocrystalline NpO{sub 2} in the solution phase. The resulting irregularly shaped nanocrystals with an average size of 4 nm exhibit a face-centered cubic (fcc), fluorite-type structure (space group Fm anti 3m). The NCs tend to agglomerate under ambient conditions due to the weakly charged hydrodynamic surface at neutral pH (zetapotential ζ ∝0 mV). The formation of micron-sized agglomerates, composed of nanocrystals of 2-5 nm in size, and the subsequent precipitation cause immobilization of the major amount of Np(IV) in the Np carbonate system. Agglomeration of NpO{sub 2} nanocrystals in dependence on time was indicated by PCS and UV-vis absorption spectroscopy with the changes of baseline characteristics and absorption maximum at 742 nm. Hitherto, unknown polynuclear species as intermediate species of NpO{sub 2} nanocrystal formation were isolated from solution and observed by HR-TEM. These polynuclear Np species appear as dimers, trimers and hexanuclear compounds in analogy with those reported for other actinides

  17. Dental cavities

    Science.gov (United States)

    ... leading to cavities. Treatment may involve: Fillings Crowns Root canals Dentists fill teeth by removing the decayed tooth ... gold, porcelain, or porcelain attached to metal. A root canal is recommended if the nerve in a tooth ...

  18. radiofrequency cavity

    CERN Multimedia

    1988-01-01

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  19. Standard enthalpy of formation of L-glutamine and the products of its dissociation in aqueous solutions

    Science.gov (United States)

    Kochergina, L. A.; Lytkin, A. I.; Krutova, O. N.; Damrina, K. V.

    2014-03-01

    Heat effects of the dissolution of crystalline L-glutamine in water and lithium hydroxide solutions were determined by direct calorimetry at 298.15 K. Standard enthalpies of formation of L-glutamine and the products of its dissociation in aqueous solution were calculated.

  20. A study of the formation of nanometer-scale cavities in helium-implanted 4H-SiC

    International Nuclear Information System (INIS)

    In this work, the annealing behavior of microstructures in 4H-SiC helium-implanted at about 500 K to moderate doses (2.5-5) x 1016 ions cm-2 is studied by combining transmission electron microscopy (TEM) and Rutherford backscattering spectrometry (RBS). It is found that a low concentration of planar clusters of helium bubbles in ring structures was formed in a narrow range of dose in a well-defined depth region of the specimens on annealing above 973 K. The formation of the bubble layer is associated with remarkable distortion and deformation in the matrix. A simple model based on the frozen matrix assumption was developed to study the production of defects in SiC below the temperature of vacancy mobility. We found that the main features of the depth distribution of the bubble layer can be understood using this model if assuming the planar clusters of bubbles evolve from vacancy clusters larger than a critical size through an intermediate stage of helium platelets

  1. Ox red-metric study of complex formation processes of manganese (II, III) in glycin aqueous solution

    International Nuclear Information System (INIS)

    Present article is devoted to ox red-metric study of complex formation processes of manganese (II, III) in glycin aqueous solution. The possibility of application of ox red-metric method for study of complex formation processes of manganese (II, III) was shown. The composition of complex compounds was determined.

  2. Effect of parenteral nutrition solutions on biofilm formation of coagulase-negative Staphylococci: An experimental study

    Directory of Open Access Journals (Sweden)

    J. Sedef Göçmen

    2012-12-01

    Full Text Available Objectives: In our study we investigated the effects ofparenteral nutrition (PN solutions on Coagulase negativestaphylococci (CoNS biofilm production.Materials and methods: Thirty nine CoNS strains isolatedfrom hemocultures and a reference strain (ATCC 12228Staphylococcus epidermidis were included. Bacterial dilutionswere made in Tryptic Soy Broth (TSB. The experimentalmediums were 1. Glucose, 2. Amino acid, 3. Lipid,4. Glucose+ Amino acid+ lipid, 5. Glucose+ Amino acid, 6.Glucose+ Lipid, 7. Amino acid+ Lipid, and 8. Control (TSB.Biofilm formation was evaluated by “quantitative microdilutionplaque test”. The values greater than cut off valueare considered as positive. Biofilm positivity was dividedinto 3 groups (mild, moderate and intensive and all otherstrains under cutoff value were accepted as negative. Thenumbers of biofilm positive strains derived from 1-7. mediumswere compared with each other, and with the resultsof control.Results: The three-component PN solution and two componentPN solutions containing glucose+ lipid and aminoacid+ lipid were found to increase the biofilm productionactivity of CoNS when compared to the control group.Slime positivity in medium 1 and 2 was lower than controlsignificantly, in medium 4, 6, and 7 slime positivity washigher considerably. The indifferent results were obtainedwithin the mediums 1, 2, 3 and within the mediums 4, 5, 6,and 7.Conclusions: In our study, it was found that, glucose, aminoacid and lipid solutions which were building structuresof PN decreased the biofilm production when used solitary.However use of the compounds increased the biofilmproduction. Therefore, we can conclude that PN solutionsgiven as mixtures in routine practice increase the risk ofcatheter infection. J Clin Exp Invest 2012; 3(4: 505-509Key words: Catheter-related infections, biofilm, parenteralnutrition

  3. On the formation, growth, and shapes of solution pipes - insights from numerical modeling

    Science.gov (United States)

    Szymczak, Piotr; Tredak, Hanna; Upadhyay, Virat; Kondratiuk, Paweł; Ladd, Anthony J. C.

    2015-04-01

    Cylindrical, vertical structures called solution pipes are a characteristic feature of epikarst, encountered in different parts of the world, both in relatively cold areas such as England and Poland (where their formation is linked to glacial processes) [1] and in coastal areas in tropical or subtropical climate (Bermuda, Australia, South Africa, Caribbean, Mediterranean) [2,3]. They are invariably associated with weakly cemented, porous limestones and relatively high groundwater fluxes. Many of them develop under the colluvial sandy cover and contain the fill of clayey silt. Although it is widely accepted that they are solutional in origin, the exact mechanism by which the flow becomes focused is still under debate. The hypotheses include the concentration of acidified water around stems and roots of plants, or the presence of pre-existing fractures or steeply dipping bedding planes, which would determine the points of entry for the focused groundwater flows. However, there are field sites where neither of this mechanisms was apparently at play and yet the pipes are formed in large quantities [1]. In this communication we show that the systems of solution pipes can develop spontaneously in nearly uniform matrix due to the reactive-infiltration instability: a homogeneous porous matrix is unstable with respect to small variations in local permeability; regions of high permeability dissolve faster because of enhanced transport of reactants, which leads to increased rippling of the front. This leads to the formation of a system of solution pipes which then advance into the matrix. We study this process numerically, by a combination of 2d- and 3d-simulations, solving the coupled flow and transport equations at the Darcy scale. The relative simplicity of this system (pipes developing in a uniform porous matrix, without any pre-existing structure) makes it very attractive from the modeling standpoint. We quantify the factors which control the pipe diameters and the

  4. Formation of hydroxyl radical from San Joaquin Valley particles extracted in a cell-free solution

    Science.gov (United States)

    Shen, H.; Anastasio, C.

    2011-06-01

    Previous studies have suggested that the adverse health effects from ambient particulate matter (PM) are linked to the formation of reactive oxygen species (ROS) by PM. While hydroxyl radical (•OH) is the most reactive of the ROS species, there are few quantitative studies of •OH generation from PM. Here we report on •OH formation from PM collected at an urban (Fresno) and rural (Westside) site in the San Joaquin Valley (SJV) of California. We quantified •OH in PM extracts using a cell-free, phosphate-buffered saline (PBS) solution with or without 50 μM ascorbate (Asc). The results show that generally the urban Fresno PM generates much more •OH than the rural Westside PM. The presence of Asc at a physiologically relevant concentration in the extraction solution greatly enhances •OH formation from all the samples. Fine PM (PM2.5) generally makes more •OH than the corresponding coarse PM (PMcf, i.e., 2.5 to 10 μm) normalized by air volume collected, while the coarse PM typically generates more •OH normalized by PM mass. •OH production by SJV PM is reduced on average by (97 ± 6) % when the transition metal chelator desferoxamine (DSF) is added to the extraction solution, indicating a dominant role of transition metals. By measuring calibration curves of •OH generation from copper and iron, and quantifying copper and iron concentrations in our particle extracts, we find that PBS-soluble copper is primarily responsible for •OH production by the SJV PM, while iron often makes a significant contribution. Extrapolating our results to expected burdens of PM-derived •OH in human lung lining fluid suggests that typical daily PM exposures in the San Joaquin Valley are unlikely to result in a high amount of pulmonary •OH, although high PM events could produce much higher levels of •OH, which might lead to cytotoxicity.

  5. Formation of hydroxyl radical from San Joaquin Valley particles extracted in a cell-free solution

    Directory of Open Access Journals (Sweden)

    H. Shen

    2011-06-01

    Full Text Available Previous studies have suggested that the adverse health effects from ambient particulate matter (PM are linked to the formation of reactive oxygen species (ROS by PM. While hydroxyl radical (OH is the most reactive of the ROS species, there are few quantitative studies of OH generation from PM. Here we report on OH formation from PM collected at an urban (Fresno and rural (Westside site in the San Joaquin Valley (SJV of California. We quantified OH in PM extracts using a cell-free, phosphate-buffered saline (PBS solution with or without 50 μM ascorbate (Asc. The results show that generally the urban Fresno PM generates much more OH than the rural Westside PM. The presence of Asc at a physiologically relevant concentration in the extraction solution greatly enhances OH formation from all the samples. Fine PM (PM2.5 generally makes more OH than the corresponding coarse PM (PMcf, i.e., 2.5 to 10 μm normalized by air volume collected, while the coarse PM typically generates more OH normalized by PM mass. OH production by SJV PM is reduced on average by (97 ± 6 % when the transition metal chelator desferoxamine (DSF is added to the extraction solution, indicating a dominant role of transition metals. By measuring calibration curves of OH generation from copper and iron, and quantifying copper and iron concentrations in our particle extracts, we find that PBS-soluble copper is primarily responsible for OH production by the SJV PM, while iron often makes a significant contribution. Extrapolating our results to expected burdens of PM-derived OH in human lung lining fluid suggests that typical daily PM exposures in the San Joaquin Valley are unlikely to result in a high amount of pulmonary OH, although high PM events could produce much higher levels

  6. Logic of historical development of the formation process of architectural and construction solutions

    Directory of Open Access Journals (Sweden)

    Baranov Valeriy Aleksandrovich

    2014-05-01

    necessary condition of its working implementation, and so-called "designing designing" becomes its necessary stage. Achievements of each of the revealed stages don't disappear, and pass into a new stage of development as a subordinated level, carrying out the certain function available to its opportunities. Each subsequent level differs from the previous one, first, in the wider covered subject content of activity of ACD formation, secondly, increase in the depth of penetration into ACD problem, and, thirdly, the contents, which is meant by the concept "architectural and construction solution" at each level.

  7. Formation of salbutamol sulphate microparticles using solution enhanced dispersion by supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    Abdolhossein Rouholamini Najafabadi

    2005-01-01

    Full Text Available Salbutamol sulphate (SS was precipitated by supercritical carbon dioxide (SC-CO2 using a homemade system at two different pressures. This process is characterized by spraying a methanolic solution of the drug into the supercritical fluid (SCF, extraction of the solvent by SC-CO2 and formation of drug particles. The morphology and size distribution of precipitated SS particles were characterized using scanning electron microscope and laser diffraction particle size analyzer respectively. FTIR spectra were used before and after processing to asses crystal modifications. Depending on the processing conditions, needle-like and flake-like particles with different size distributions were observed. The average size of the flake like particles was less than needle-like particles and the span parameter showed a narrower size distribution of the processed in comparison with the unprocessed materials. Analysis by FTIR showed that there was no significant effect on the structure of the drug under these processing conditions.

  8. Standard molar enthalpy of formation of TbPO4(s) using solution calorimeter

    International Nuclear Information System (INIS)

    Monazite, LnPO4 (Ln = La-Tb) is a promising waste form for immobilization of trivalent actinides such as PuIII, AmIII and CmIII with loading of actinides up to 25 wt%. The crystalline monazite ceramics are resistance to radiation damage and stable in aqueous medium. Hence, it can be used as matrix to store long lived minor actinides. Evaluation of the long-term stability and reactivity of rare-earth phosphates with environments requires determination of their thermodynamic properties. In continuation with our earlier work program to measure thermodynamic data of rare-earth phosphates at 298.15 K using isoperibol solution calorimeter we have measured the enthalpy of formation of TbPO4(s) in this study

  9. Photoinduced Formation of Colloidal Silver in Nitrocellulose Solutions Containing Titanium Alkoxides

    Science.gov (United States)

    Kulak, A. I.; Branitsky, G. A.

    2016-07-01

    The study shows the possibility of photo-induced reduction of silver nitrate and formation of stable colloidal silver particles in an isopropanol-N,N-dimethylacetamide solution of titanium alkoxide (polybutyl titanate) stabilized by nitrocellulose. It is established that titanium alkoxide and the products of its partial hydrolysis in the liquid composition play the role of a photocatalyst for the reduction of silver ions; the introduction of nitric or acetic acid additives to the composition significantly increases its photosensitivity. The films deposited from the liquid composition, previously irradiated with visible or UV light, consist of hydrated titanium dioxide and nitrocellulose with incorporated colloidal silver. Thermal treatment of the films at 150-245°C leads to the decomposition of nitrocellulose and an increase in the absorption by silver particles.

  10. Formation and Destruction of NDELA in 30 wt% MEA (Monoethanolamine) and 50 wt% DEA (Diethanolamine) Solutions

    International Nuclear Information System (INIS)

    The formation of nitrosodiethanolamine (NDELA) in a lab scale pilot was studied by feeding known amounts of nitrogen oxide and nitrogen dioxide into the gas entering the absorber. In the same pilot, the destruction by UV-irradiation of NDELA present in the solvent was studied. Two campaigns were performed, one with 30 wt% monoethanolamine (MEA) and one with 50 wt% diethanolamine (DEA). During the DEA campaign the destruction of NDELA in the water wash section was also tested. Additionally, degraded solution samples withdrawn from the pilot were tested for thermal degradation. The results show that NDELA was formed when nitrogen oxide and nitrogen dioxide were present. Destruction of NDELA with UV-light in the solvent loop was found to be slow. In the water wash section, the UV-light destroyed the NDELA effectively. NDELA was found to degrade during the thermal degradation studies at 135 deg. C. (authors)

  11. Influence of doping and solid solution formation on the thermoelectric properties of chalcopyrite semiconductors

    International Nuclear Information System (INIS)

    Highlights: • Zinc substituting on the cation site in CuInTe2 and CuGaTe2 is a p-type dopant. • Thermoelectric power factor optimized by 1% zinc doping. • CuInTe2–CuGaTe2 solid solution formation reduces the lattice thermal conductivity. • Optimized samples have dimensionless thermoelectric figure of merit in excess of unity over a wide temperature range. - Abstract: We have investigated the influence of zinc doping on the thermoelectric properties of CuInTe2–CuGaTe2 solid solution alloys. Undoped end-member compounds display typical p-type semiconducting behavior, with a negative temperature coefficient of resistivity and large Seebeck coefficient. With zinc substituting for indium or gallium, the hole concentration is increased and the electrical transport behavior evolves into that of a degenerate semiconductor, with both electrical resistivity and Seebeck coefficient increasing with temperature up to the highest temperature measured. For undoped samples the thermoelectric power factor is maximized close to 750 K, while in doped specimens the maximum occurs at much lower temperature. Substitution of gallium for indium induces significant phonon scattering and thermal conductivity reduction below 500 K. The dimensionless figure of merit rises to above unity over a range of compositions in these chalcopyrite compounds, with optimized samples reaching a figure of merit of 1.3

  12. Influence of doping and solid solution formation on the thermoelectric properties of chalcopyrite semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Carr, Winston D. [Department of Physics & Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Morelli, Donald T. [Department of Physics & Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing, MI 48824 (United States)

    2015-05-05

    Highlights: • Zinc substituting on the cation site in CuInTe{sub 2} and CuGaTe{sub 2} is a p-type dopant. • Thermoelectric power factor optimized by 1% zinc doping. • CuInTe{sub 2}–CuGaTe{sub 2} solid solution formation reduces the lattice thermal conductivity. • Optimized samples have dimensionless thermoelectric figure of merit in excess of unity over a wide temperature range. - Abstract: We have investigated the influence of zinc doping on the thermoelectric properties of CuInTe{sub 2}–CuGaTe{sub 2} solid solution alloys. Undoped end-member compounds display typical p-type semiconducting behavior, with a negative temperature coefficient of resistivity and large Seebeck coefficient. With zinc substituting for indium or gallium, the hole concentration is increased and the electrical transport behavior evolves into that of a degenerate semiconductor, with both electrical resistivity and Seebeck coefficient increasing with temperature up to the highest temperature measured. For undoped samples the thermoelectric power factor is maximized close to 750 K, while in doped specimens the maximum occurs at much lower temperature. Substitution of gallium for indium induces significant phonon scattering and thermal conductivity reduction below 500 K. The dimensionless figure of merit rises to above unity over a range of compositions in these chalcopyrite compounds, with optimized samples reaching a figure of merit of 1.3.

  13. Mechanism of formation of silver nanoparticles in MAG–DMAEMA copolymer aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Shvedchenko, Dmitry O. [A.V. Shubnikov Institute of Crystallography of Russian Academy of Sciences (Russian Federation); Nekrasova, Tatiana N.; Nazarova, Olga V. [Institute of Macromolecular Compounds of Russian Academy of Sciences (Russian Federation); Buffat, Philippe A. [Centre Interdisciplinaire de Microscopie Electronique, Station 12, Ecole Polytechnique Fédérale de Lausanne (Switzerland); Suvorova, Elena I., E-mail: elena.suvorova@epfl.ch, E-mail: suvorova@ns.crys.ras.ru [A.V. Shubnikov Institute of Crystallography of Russian Academy of Sciences (Russian Federation)

    2015-06-15

    Dispersed Ag nanoparticles were prepared in aqueous solutions in the presence of pure poly[2-(dimethylamino)ethyl methacrylate] (poly-DMAEMA), poly[2-deoxy-2-methacrylamido-d-glucose] (poly-MAG), and their copolymers of poly[MAG–DMAEMA] with different mole fractions. Polymers contributed to the silver reduction, formation of nanoparticles, and stabilization of suspensions. No agglomerations of nanoparticles are formed. For each sample, more than one thousand silver particles were measured by transmission and scanning transmission electron microscopy to determine their number vs diameter and volume versus diameter distributions. The samples with the smallest nanoparticle mode diameter of 2.3 nm were formed in DMAEMA homopolymer suspension, while the mode diameter increased up to 13.3 nm in copolymers depending on the mole fraction of DMAEMA. A model of Ag nanoparticles’ growth taking into account the structure of the copolymers and the amount of reducing centers per monomer is proposed. The volume fraction of large Ag particles (>15–20 nm) in the tail of distributions was determined to estimate the part of less efficient nanoparticles assuming that only surface atoms are active. The largest volume occupied by big particles is measured in the solution with pure poly-MAG. Figures of merit, as the ratio of particle area to total volume of particles, were compared for five systems of Ag NPs/polymer. They can be understood from an economical point of view as the total silver investment compared to efficiency.

  14. Exact solution for the hypergeometric Green's function describing spectral formation in x-ray pulsars

    International Nuclear Information System (INIS)

    An eigenfunction expansion method involving hypergeometric functions is used to solve the partial differential equation governing the transport of radiation in an x-ray pulsar accretion column containing a radiative shock. The procedure yields the exact solution for the Green's function, which describes the scattering of monochromatic radiation injected into the column from a source located near the surface of the star. Collisions between the injected photons and the infalling electrons cause the radiation to gain energy as it diffuses through the gas and gradually escapes by passing through the walls of the column. The presence of the shock enhances the energization of the radiation and creates a power-law spectrum at high energies, which is typical for a Fermi process. The analytical solution for the Green's function provides important physical insight into the spectral formation process in x-ray pulsars, and it also has direct relevance for the interpretation of spectral data for these sources. Additional interesting mathematical aspects of the problem include the establishment of a closed-form expression for the quadratic normalization integrals of the orthogonal eigenfunctions, and the derivation of a new summation formula involving products of hypergeometric functions. By taking various limits of the general expressions, we also develop new linear and bilinear generating functions for the Jacobi polynomials

  15. Controlled formation of ag nanoparticles by means of long-chain sodium polyacrylates in dilute solution.

    Science.gov (United States)

    Huber, Klaus; Witte, Thomas; Hollmann, Jutta; Keuker-Baumann, Susanne

    2007-02-01

    A new tool is presented to control formation of Ag nanoparticles. Small amounts of silver ions were added to dilute solutions of long-chain sodium polyacrylates (NaPA). Four NaPA samples covering a molar mass regime of 97 kD polyacrylate coils toward compact structures. Coil shrinking and aggregation was revealed by means of time-resolved static light scattering. If exposed to UV-radiation, small Ag particles formed within the shrunken anionic polyacrylate coils. The Ag nanoparticles were identified by means of an enhanced light scattering and a characteristic plasmon absorption band around 410 nm. No such Ag particle formation could be observed even at 5 times larger concentrations of Ag(+) and NaPA if the two smallest polyacrylate samples have been used under otherwise equal conditions. This molar mass sensitive response of NaPA to Ag(+)-addition suggests an interesting phenomenon: if the coil size of the NaPa chains, which act as Ag(+) collectors, is large enough, local Ag(+) concentration in these coil-shaped Ag(+) containers exceeds a critical value, and irradiation with UV generates Ag nanoparticles. PMID:17263389

  16. Uptake of oxo-anions by cements through solid-solution formation: experimental evidence and modelling

    International Nuclear Information System (INIS)

    Uptake experiments were carried out with selenate and chromate on fresh and leached Portland and high-alumina cements; and in addition with selenate and selenite on synthetic ettringite. In all experiments with cements, exceptionally high uptake could be observed under conditions where significant amounts of secondary ettringite were formed. Experimental data obtained for pure ettringite corroborated the important role of this mineral phase. However, uptake kinetics show opposite trends in these two systems, which can be viewed as end-members of the same process: Where a fast precipitation of secondary ettringite occurred, initial uptake was high, with Kd values in the range of ∼ 1-5 m3/kg for Se(VI), but decreased with time. Uptake by pre-formed (primary) ettringite initially gave lower Kd values (∼ 0.1 m3/kg), which increased with time. After prolonged equilibration times, the two systems started to approach each other. Concurrent measurements of sulphate concentrations allowed to extract a mean partition coefficient for the solid-solution formation of selenite and selenate with ettringite. Based on this simple solid-solution model, a pragmatic quantitative relation was developed that permits to estimate Kd for Se(VI) on whole cement as a function of the concentrations of sulphate in the cement and in the solution. A test against experimental data shows reasonably good agreement between measurements and calculations. This relation can also be directly applied to estimate Kd values of chromate (and perrhenate) by different cements, indicating the same uptake mechanism. The approach may be less well suited for Se(IV), whose uptake on cement appears to be related mainly to minerals other than ettringite. (orig.)

  17. Complex formation between neptunium(V) and various thiosemicarbazide derivatives in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Chuguryan, D.G.; Dzyubenko, V.I.; Gerbeleu, N.V.

    1987-01-01

    Complex formation between neptunium(V) and various thiosemicarbazide derivatives in solution has been studied spectrophotometrically in the pH range 4-10. Stepwise formation of three types of complexes, with composition NpO/sub 2/HA, NpO/sub 2/A/sup -/, and NpOHA/sup 2 -/, has been demonstrated with salicylaldehyde thiosemicarbazone (H/sub 2/L) and salicylaldehyde S-methyl-isothiosemicarbazone (H/sub 2/Q) at t = 25 +/- 1/sup 0/C and ..mu.. = 0.05. The logarithmic stability constants of the first two complexes are 5.14 +/- 0.06, 11.85 +/- 0.04 and 8.42 +/- 0.09, 13.33 +/- 0.015 for H/sub 2/L and H/sub 2/Q, respectively; equilibrium constants for the formation of hydroxo complexes of the form NpO/sub 2/OHL/sup 2 -/ and NpO/sub 2/OHQ/sup 2 -/ were also determined, and found to be equal to (2.23 +/-0.37) x 10/sup -5/ and (5.02 +/- 0.9) x 10/sup -5/, respectively. In the case of S-methyl-N/sub 1/,N/sub 4/-bis(salicylidene)isothiosemicarbazide (H/sub 2/Z), only one type of complex is formed under these experimental conditions, namely, NpO/sub 2/Z/sup -/, with a logarithmic stability constant of 4.78 +/- 0.03. Dissociation constants for H/sub 2/Q and H/sub 2/Z were also determined.

  18. Investigation into formation of nanoparticles of tetravalent neptunium in slightly alkaline aqueous solution

    International Nuclear Information System (INIS)

    Considering the worldwide growing discharge of minor actinides and the current need for geological disposal facilities for radioactive waste, this work provides a contribution to the safety case concerning Np transport if it would be released from deep repository sites and moving from alkaline cement conditions (near-field) to more neutral environmental conditions (far-field). The reducing conditions in a nuclear waste repository render neptunium tetravalent, which is assumed to be immobile in aqueous environment due to the low solubility solution of Np(IV). For tetravalent actinide nuclides, the most significant transport should occur via colloidal particles. This work demonstrates the formation of intrinsic neptunium dioxide nanocrystals and amorphous Np(IV) silica colloids under environmentally relevant conditions. The dissociation of the initial soluble Np(IV) complex (i.e. [Np(IV)(CO3)5]6-) induces the intrinsic formation of nanocrystalline NpO2 in the solution phase. The resulting irregularly shaped nanocrystals with an average size of 4 nm exhibit a face-centered cubic (fcc), fluorite-type structure (space group Fm anti 3m). The NCs tend to agglomerate under ambient conditions due to the weakly charged hydrodynamic surface at neutral pH (zetapotential ζ ∝0 mV). The formation of micron-sized agglomerates, composed of nanocrystals of 2-5 nm in size, and the subsequent precipitation cause immobilization of the major amount of Np(IV) in the Np carbonate system. Agglomeration of NpO2 nanocrystals in dependence on time was indicated by PCS and UV-vis absorption spectroscopy with the changes of baseline characteristics and absorption maximum at 742 nm. Hitherto, unknown polynuclear species as intermediate species of NpO2 nanocrystal formation were isolated from solution and observed by HR-TEM. These polynuclear Np species appear as dimers, trimers and hexanuclear compounds in analogy with those reported for other actinides. Intrinsic formation of NpO2 (fcc

  19. accelerating cavity

    CERN Multimedia

    On the inside of the cavitytThere is a layer of niobium. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment.

  20. Solution mining dawsonite from hydrocarbon containing formations with a chelating agent

    Science.gov (United States)

    Vinegar, Harold J.

    2009-07-07

    A method for treating an oil shale formation comprising dawsonite includes providing heat from one or more heaters to the formation to heat the formation. Hydrocarbon fluids are produced from the formation. At least some dawsonite in the formation is decomposed with the provided heat. A chelating agent is provided to the formation to dissolve at least some dawsonite decomposition products. The dissolved dawsonite decomposition products are produced from the formation.

  1. Explicit solution format for complex-valued natural frequency of beam with R-shunted piezoelectric laminate transducer

    DEFF Research Database (Denmark)

    Høgsberg, Jan Becker; Cöent, Adrien Le

    2014-01-01

    Analysis and design of resistive shunt circuits for piezoelectric damping of beam structures is often based on a representation in terms of the single target vibration mode of the beam, neglecting spill-over effects from the out-of-bandwidth or residual vibration modes. In this article, a solution...... format is derived for the complex-valued natural frequency of the beam with a shunted piezoelectric laminate transducer, where the influence from the residual modes is taken into account by a quasi-static representation. This explicit solution format contains system parameters that directly represent....... The accuracy of the explicit frequency solution format is verified by comparison with numerical results. It is found that the complex-valued natural frequency of the first vibration mode of a beam with a piezoelectric laminate transducer shunted to a resistance is estimated with sufficient accuracy...

  2. Formation of intermolecular crosslinks by the actinocin derivatives with DNA in interaction under conditions of semidilute solution

    International Nuclear Information System (INIS)

    Interaction of native calf thymus DNA (ctDNA) with the actinocin derivatives containing protonated diethylamino groups, dimethylamino groups and unsubstituted amino groups and having different length of the alkyl chain have been studied by the method of viscometry. An anomalous hydrodynamic behavior of solutions of DNA with very low amount of ligands prepared under conditions of semidilute solution was revealed. We assumed that such an anomalous behavior of solutions of DNA complexes with actinocin derivatives associated with the formation of intermolecular crosslinks while the preparation of the complex was in terms of overlapping of macromolecular coils in solution. Comparative study of the hydrodynamic behavior of the DNA complexes with various actinocin structures lead us to the conclusion of the formation of crosslinks by the compounds containing protonated diethylamino groups

  3. Alteration of non-metallic barriers and evolution of solution chemistry in salt formations in Germany

    International Nuclear Information System (INIS)

    Different Engineered Barrier Systems (EBS) materials considered in Germany for the sealing of repositories in salt formations are presented. Their long term behaviour in terms of interactions with salt solutions is discussed and evaluated. The discussed EBS materials are crushed salt, self sealing salt backfill, bentonite and salt concrete. Whereas the knowledge concerning the geochemical, geomechanical, hydrological and thermal behavior of crushed salt and salt concrete is well advanced further research is needed for other EBS materials. The self healing salt backfill has also been investigated in depth recently. In order to fully qualify this material large scale in situ experiments are still needed. The present knowledge on compacted bentonites in a salt environment is not yet sufficient for reliable predictions of the long-term performance in salt formations. The sealing concept of the low- and intermediate-level Radioactive Waste Repository Morsleben (ERAM) in a former rock salt and potash mine is presented. This concept is based on cementitious materials, i.e. salt concrete. The geochemical stability of different salt concretes in contact with brines expected in ERAM is addressed. It is shown how the results from leaching experiments and geochemical modelling are used in the safety analyses and how the chemical boundary conditions prevailing in the EBS influence the development of the permeability of the sealing system and thus control the radionuclide release. As a result of modelling the behaviour of the seals in the safety assessment it is shown, that the seals are corroded within a time span of about 20 000 years. The influence of the uncertainty in the model parameters on the safety of the repository was assessed by a variation of the initial permeability of the seal. The maximum dose rate resulting from the radionuclide release from ERAM is nearly independent of the variation of the initial permeability within four orders of magnitude. (authors)

  4. Self-motion of a phenanthroline disk on divalent metal ion aqueous solutions coupled with complex formation

    OpenAIRE

    Nakata, Satoshi; Arima, Yoshie

    2008-01-01

    The self-motion of a 1,10-phenanthroline disk on divalent metal ion aqueous solutions was investigated as a simple autonomous motor coupled with complex formation. The characteristic features of motion (continuous and oscillatory motion) and their concentration regions differed among metal ions, and the frequency of oscillatory motion depended on the temperature of the aqueous solution. The nature of the characteristic motion is discussed in relation to the stability constant of complex forma...

  5. Particle formation and characterization of mackerel reaction oil by gas saturated solution process.

    Science.gov (United States)

    Tanbirul Haque, A S M; Chun, Byung-Soo

    2016-01-01

    Most of the health benefits of fish oil can be attributed to the presence of omega-3 fatty acids like Docosahexenoic acid (DHA) and Eicosapentaenoic acid (EPA). There are few dietary sources of EPA and DHA other than oily fish. EPA and DHA have great potential effect on human health. In this research, Supercritical carbon dioxide (scCO2) extracted mackerel oil was reacted by enzyme at different systems to improve the EPA and DHA. Different types of immobilize enzyme TL-IM, RM-IM, Novozyme 435 were assessed for improving PUFAs. Best result was found at non-pressurized system using TL-IM. Reacted oil particle were obtained with polyethylene glycol by gas saturated solution process (PGSS). Different parameters like temperature, pressure, agitation speed and nozzle size effect on particle formulation were observed. SEM and PSA analysis showed, small size non spherical particles were obtained. It was found that after particle formation poly unsaturated fatty acids (PUFAs) were present in particle as same in oil. PUFAs release from particle was almost linear against constant time duration. Oil quality in particle not change significantly, in this contrast this study will be helpful for food and pharmaceutical industry to provide high EPA and DHA containing powder. PMID:26787949

  6. Magic number effect on cluster formation of polyhydroxylated fullerenes in water-alcohol binary solution

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Yuji; Ueno, Hiroshi; Kokubo, Ken, E-mail: kokubo@chem.eng.osaka-u.ac.jp; Ikuma, Naohiko; Oshima, Takumi [Osaka University, Division of Applied Chemistry, Graduate School of Engineering (Japan)

    2013-06-15

    Due to the spherical shape with a diameter of ca. 1 nm, the aggregation behaviour of fullerene C{sub 60} is very interesting in view of the possible formation of magic number particle in a similar manner as metal cluster in gas phase. Herein, we report for the first time the magic number aggregation behaviours of polyhydroxylated fullerenol C{sub 60}(OH){sub 36} in water-alcohol (methanol, ethanol and 1-propanol) binary solution with increasing alcohol component. The diameters of particle were ca. 6-8 nm depending on the alcohol used. The particle sizes were precisely measured by the novel-induced grating method which is superior for the particle-size measurement in single-nano region (1-10 nm). The magic number cluster was also detected by scanning probe microscopy observation. However, such aggregation behaviours were not found in DMSO-alcohol system or for the use of less hydroxylated C{sub 60}(OH){sub 10}.

  7. Formation of an 8-hydroxyguanine moiety in deoxyribonucleic acid on gamma-irradiation in aqueous solution

    International Nuclear Information System (INIS)

    Isolation and characterization of a novel radiation-induced product, i.e., the 8-hydroxyguanine residue, produced in deoxyribonucleic acid (DNA), 2'-deoxyguanosine, and 2'-deoxyguanosine 5'-monophosphate by gamma-irradiation in aqueous solution, are described. For this purpose, gamma-irradiated DNA was first hydrolyzed with a mixture of four enzymes, i.e., DNase I, spleen and snake venom exonucleases, and alkaline phosphatase. Analysis of the resulting mixture by capillary gas chromatography-mass spectrometry after trimethylsilylation revealed the presence of a product, which was identified as 8-hydroxy-2'-deoxyguanosine on the basis of the typical fragment ions of its trimethylsilyl (Me3Si) derivative. This product was then isolated by using reversed-phase high-performance liquid chromatography. The UV and proton nuclear magnetic resonance spectra taken from the isolated product confirmed the structure suggested by the mass spectrum of its Me3Si derivative. The yield of 8-hydroxyguanine was also measured. Its mechanism of formation is believed to involve OH radical addition to the C-8 position of guanine followed by oxidation of the radical adduct

  8. Solution mining and heating by oxidation for treating hydrocarbon containing formations

    Science.gov (United States)

    Vinegar, Harold J.; Stegemeier, George Leo

    2009-06-23

    A method for treating an oil shale formation comprising nahcolite includes providing a first fluid to a portion of the formation. A second fluid is produced from the portion. The second fluid includes at least some nahcolite dissolved in the first fluid. A controlled amount of oxidant is provided to the portion of the formation. Hydrocarbon fluids are produced from the formation.

  9. Design and Construction of Experiment for Direct Electron Irradiation of Uranyl Sulfate Solution: Bubble Formation and Thermal Hydraulics Studies

    Energy Technology Data Exchange (ETDEWEB)

    Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, Roman [Argonne National Lab. (ANL), Argonne, IL (United States); Makarashvili, Vakho [Argonne National Lab. (ANL), Argonne, IL (United States); Heltemes, Thad [Argonne National Lab. (ANL), Argonne, IL (United States); Sun, Zaijing [Argonne National Lab. (ANL), Argonne, IL (United States); Wardle, Kent E. [Argonne National Lab. (ANL), Argonne, IL (United States); Bailey, James [Argonne National Lab. (ANL), Argonne, IL (United States); Quigley, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States); Stepinski, Dominique [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George [Argonne National Lab. (ANL), Argonne, IL (United States)

    2014-10-01

    Argonne is assisting SHINE Medical Technologies in developing SHINE, a system for producing fission-product 99Mo using a D/T-accelerator to produce fission in a non-critical target solution of aqueous uranyl sulfate. We have developed an experimental setup for studying thermal-hydraulics and bubble formation in the uranyl sulfate solution to simulate conditions expected in the SHINE target solution during irradiation. A direct electron beam from the linac accelerator will be used to irradiate a 20 L solution (sector of the solution vessel). Because the solution will undergo radiolytic decomposition, we will be able to study bubble formation and dynamics and effects of convection and temperature on bubble behavior. These experiments will serve as a verification/ validation tool for the thermal-hydraulic model. Utilization of the direct electron beam for irradiation allows homogeneous heating of a large solution volume and simplifies observation of the bubble dynamics simultaneously with thermal-hydraulic data collection, which will complement data collected during operation of the miniSHINE experiment. Irradiation will be conducted using a 30-40 MeV electron beam from the high-power linac accelerator. The total electron-beam power will be 20 kW, which will yield a power density on the order of 1 kW/L. The solution volume will be cooled on the front and back surfaces and central tube to mimic the geometry of the proposed SHINE solution vessel. Also, multiple thermocouples will be inserted into the solution vessel to map thermal profiles. The experimental design is now complete, and installation and testing are in progress.

  10. Enthalpy of formation of quasicrystalline phase and ternary solid solutions in the Al-Fe-Cu system

    Institute of Scientific and Technical Information of China (English)

    I.A. Tomilin; S.D. Kaloshkin; V. V. Tcherdyntsev

    2006-01-01

    Standard enthalpies of formation of quasicrystalline phase and the ternary solid solutions in the Al-Fe-Cu system and the intermetallic compound FeAl were determined by the means of solution calorimetry. The quasicrystalline phase was prepared using two different methods. The first method (Ⅰ) consisted of ball milling the mixture of powders of pure aluminum copper and iron in a planetary mill with subsequent compacting by hot pressing and annealing. The second method (Ⅱ) consisted of arc melting of the components in argon atmosphere followed by annealing. The latter method was used for preparing the compound FeAl and the solid solutions. The phases were identified using the XRD method. The enthalpy of the formation was determined for the quasicrystalline phase of the composition Al62Cu25.5Fe12.5 and the ternary BCC solid solutions Al35Cu14Fe51, Al40Cu17Fe43, and Al50.4Cu19.6Fe30. The measured enthalpy of formation of the intermetallic com pound FeAl is in good agreement with the earlier published data. The enthaipies of formation of the quasicrystalline phases prepared using two different methods are close to each other, namely, -22.7±3.4 (method Ⅰ) and -21.3±2.1 (method Ⅱ)k J/mol.

  11. Analytical solutions of jam pattern formation on a ring for a class of optimal velocity traffic models

    DEFF Research Database (Denmark)

    Gaididei, Yuri Borisovich; Berkemer, Rainer; Caputo, Jean Guy;

    2009-01-01

    A follow-the-leader model of traffic flow on a closed loop is considered in the framework of the extended optimal velocity (OV) model where the driver reacts to both the following and the preceding car. Periodic wave train solutions that describe the formation of traffic congestion patterns are...

  12. Crystal structure and solution species of Ce(III) and Ce(IV) formates: from mononuclear to hexanuclear complexes.

    Science.gov (United States)

    Hennig, Christoph; Ikeda-Ohno, Atsushi; Kraus, Werner; Weiss, Stephan; Pattison, Philip; Emerich, Hermann; Abdala, Paula M; Scheinost, Andreas C

    2013-10-21

    Cerium(III) and cerium(IV) both form formate complexes. However, their species in aqueous solution and the solid-state structures are surprisingly different. The species in aqueous solutions were investigated with Ce K-edge EXAFS spectroscopy. Ce(III) formate shows only mononuclear complexes, which is in agreement with the predicted mononuclear species of Ce(HCOO)(2+) and Ce(HCOO)2(+). In contrast, Ce(IV) formate forms in aqueous solution a stable hexanuclear complex of [Ce6(μ3-O)4(μ3-OH)4(HCOO)x(NO3)y](12-x-y). The structural differences reflect the different influence of hydrolysis, which is weak for Ce(III) and strong for Ce(IV). Hydrolysis of Ce(IV) ions causes initial polymerization while complexation through HCOO(-) results in 12 chelate rings stabilizing the hexanuclear Ce(IV) complex. Crystals were grown from the above-mentioned solutions. Two crystal structures of Ce(IV) formate were determined. Both form a hexanuclear complex with a [Ce6(μ3-O)4(μ3-OH)4](12+) core in aqueous HNO3/HCOOH solution. The pH titration with NaOH resulted in a structure with the composition [Ce6(μ3-O)4(μ3-OH)4(HCOO)10(NO3)2(H2O)3]·(H2O)9.5, while the pH adjustment with NH3 resulted in [Ce6(μ3-O)4(μ3-OH)4(HCOO)10(NO3)4]·(NO3)3(NH4)5(H2O)5. Furthermore, the crystal structure of Ce(III) formate, Ce(HCOO)3, was determined. The coordination polyhedron is a tricapped trigonal prism which is formed exclusively by nine HCOO(-) ligands. The hexanuclear Ce(IV) formate species from aqueous solution is widely preserved in the crystal structure, whereas the mononuclear solution species of Ce(III) formate undergoes a polymerization during the crystallization process. PMID:24090406

  13. Thermochemical study of processes of complex formation of Cu2+ ions with L-glutamine in aqueous solutions

    Science.gov (United States)

    Gorboletova, G. G.; Gridchin, S. N.; Lutsenko, A. A.

    2010-11-01

    Heats of the interaction of Cu(NO3)2 solutions with L-glutamine solutions were measured directly by calorimetry at a temperature of 298.15 K and ionic strength values of 0.5, 1.0, and 1.5 (KNO3). Using RRSU universal software, the experimental data were subjected to rigorous mathematical treatment with allowances made for several concurrent processes in the system. The heats of formation of the CuL+ and CuL2 complexes were calculated from the calorimetric measurements. The standard heats of the complex formation of Cu2+ with L-glutamine were obtained by extrapolation to zero ionic strength. The complete thermodynamic characteristic (Δr H o, Δr G o, Δr S o) of the complex formation processes in a Cu2+—L-glutamine system was obtained.

  14. Rectangular Full Packed Format for Cholesky's Algorithm: Factorization, Solution, and Inversion

    DEFF Research Database (Denmark)

    Gustavson, Fred G.; Wasniewski, Jerzy; Dongarra, Jack J;

    2010-01-01

    We describe a new data format for storing triangular, symmetric, and Hermitian matrices called Rectangular Full Packed Format (RFPF). The standard two-dimensional arrays of Fortran and C (also known as full format) that are used to represent triangular and symmetric matrices waste nearly half...

  15. The genesis of solution pipes: Evidence from the Middle-Late Pleistocene Bridgewater Formation calcarenite, southeastern Australia

    Science.gov (United States)

    Lipar, Matej; Webb, John A.; White, Susan Q.; Grimes, Ken G.

    2015-10-01

    Solution pipes are abundant in Late Pleistocene aeolian calcarenites at Cape Bridgewater in southwestern Victoria, and were studied using field work, morphometric analysis, thin sections, mineralogical and chemical analyses, and OSL dating. The solution pipes are vertical tubes formed in aeolian limestone with matrix porosity. They are typically 0.1-1 m wide and 1-5 m deep, with rounded terminations and cemented rims up to 10 cm thick. They are overlain by palaeosols and filled mostly with palaeosol material; rhizoliths are commonly present in the solution pipe fills and the surrounding calcarenite. The solution pipes have formed by focused dissolution of aeolianite, relatively quickly after the sand deposition, and concurrently filled with soil as they developed. They most likely formed beneath trees (as a result of focused infiltration due to stemflow) or due to fingered flow (unstable wetting front that breaks into fingers as it moves downwards). Solution pipe formation was strongly dependent on climate; periods of solution pipe formation followed the deposition of aeolianites at the end of interglacials MIS 7, 9 and 11, when the dunes were stabilised by vegetation and there was sufficient rainfall for substantial subsoil dissolution. The cemented rims formed in the following drier glacial climates. Solution pipes are most abundant in the youngest aeolianite, probably reflecting the wetter climate at the end of MIS 7 that allowed a dense forest to cover the dunes. From MIS 5 to MIS 2 no deposition of calcareous sand occurred on Cape Bridgewater, and combined with a very wet interglacial period MIS 5e, resulted in additional karstification, allowing the pipes in the MIS 7 aeolianite to extend deeper and drill down into the underlying member. A well-developed calcrete layer drapes over these solution pipes, and probably formed during the dry, windy climate of the Last Glacial Maximum.

  16. Cavity magnomechanics

    Science.gov (United States)

    Zou, Chang-Ling; Zhang, Xufeng; Jiang, Liang; Tang, Hong

    2016-05-01

    Recently, cavity magnonics has attracted much attention for potential applications of coherent information transduction and hybrid quantum devices. The magnon is a collective spin wave excitation in ferromagnetic material. It is magnetically tunability, with long coherence time and non-reciprocical interaction with electro-magnetic fields. We report the coherent coupling between magnon, microwave photon and phonon. First, we demonstrate strong coupling and ultrastrong coupling between the magnon in YIG sphere and microwave photon in three-dimensional cavity. Then, based on the hybridized magnon-photon modes, we observe the triply resonant magnon-mcirowave photon-phonon coupling, where the ultrahigh-Q mechanical vibration of YIG sphere is dispersively coupled with the magnon via magnetostrictive interaction. We observe interesting phenomena, including electromagnetically induced transparency/absorption and parametric amplification. In particular, benefit from the large tunability of the magnon, we demonstrate a tunable microwave amplifier with gain as high as 30 dB. The single crystal YIG also has excellent optical properties, and thus provide a unique platform bridging MHz, GHz and THz information carriers. Finally, we present the latest progress towards coherent magnon to optical photon conversion.

  17. Formation and dissolution behaviour of niobium oxide in phosphoric acid solutions

    International Nuclear Information System (INIS)

    The effect of phosphoric acid concentration and temperature on the formation and dissolution process of niobium oxide was investigated using capacitance, potential and galvanostatic measurements. The formation rate of the niobium oxide increases with increasing phosphoric acid concentration and decreases with increasing temperature. The dissolution rate of the niobium oxide is accelerated by increasing phosphoric acid concentration and temperature. The activation energy was calculated for both the formation and dissolution process and found to be 8.93 and 16.65 kJ/mol respectively. The effect of formation voltage on the dissolution process of niobium oxide was also investigated. The oxide film formed at high-formation voltage has a more defective character than that formed at lower voltage. This enhances the dissolution process of the oxide. The effect of current density on the formation rate and the thickness during the oxide film growth was measured. (orig.)

  18. Cryogenic Electron Microscopy Studies: Structure and Formation of Self-assembled Nanostructures in Solution

    Science.gov (United States)

    Lee, Han Seung

    Cryogenic electron microscopy (Cryo-EM) techniques are among the most powerful to characterize self-assembling soft materials (colloids, polymers, and microemulsions, etc.) at the nanometer scale, without any need for implicit models or assumptions about the structure. We can even visualize structure under dynamic conditions, capturing each stage of development. In this thesis, cryo-EM has been used to investigate the formation and structure of a variety of self-assembling soft materials. Visualization is complemented by small angle X-ray scattering (SAXS), dynamic light scattering, and conductivity measurements. In each case, cryo-EM provides new insights, not otherwise available, into the nanostructure development. Self-assembly phenomena at the molecular level are critical to the performance of tremendous number of applied systems ranging from personal care products to industrial products. To evaluate these self-assembled materials, multiple characterization techniques are required. We investigated aggregation behavior of cesium dodecyl sulfate (CsDS) ionic surfactant in aqueous solution. Coupled with the real space data from cryogenic transmission electron microscopy (Cryo-TEM) and the inverse space data from SAXS, the experimental result of CsDS in aqueous solution gave a new insight in CsDS micellar structures and their development as a function of concentration. Cryo-TEM showed the presence of the liquid-like hydrocarbon core in the CsDS micelles and relatively thick shell structures at a low CsDS concentration. The core-shell sphere structure micelle shifted to core-shell cylindrical micelle structure at high concentration. The morphology and structure of paclitaxel silicate (PTX) prodrug, encapsulated with amphiphilic poly(ethylene glycol)-b-poly(lactic-co-glycolic acid) diblock copolymers were studied. The six different silicate PTX prodrug candidates were characterized with cryo-TEM. Direct imaging with cryo-TEM illustrated structure of prodrug

  19. Formation of chromium oxide nanoparticles by gamma irradiation of chromate solutions

    International Nuclear Information System (INIS)

    One of the operational and safety challenges of nuclear reactors is the corrosion of coolant system materials. Corrosion products released into the reactor coolant circulate through the reactor core and can be deposited on surfaces there where they can be neutron activated. If these radioactive species are then released into the coolant, they can migrate out of the core and deposit on piping and components located outside the biological shield of the reactor core. These activated corrosion products pose a radiological hazard to plant workers. The radiolysis of water produces redox-active radicals and molecules that can interact very effectively with metallic corrosion products, changing their oxidation states. The solubility of hydrated metal species varies considerably depending on their oxidation state. For example, ferrous iron is several orders of magnitude more soluble than ferric iron at acidic and neutral pHs, while CrVI species are much more soluble than CrIII species at all pHs. Conversion of more soluble metal ions to less soluble ions will promote precipitation of metal oxide colloidal particles. The conversion of a dissolved ion to a particle will change the transport behaviour of corrosion products and their removal efficiency from system surfaces or by a purification system. Hence, a well-founded understanding of the behaviour of corrosion product ions in a radiolytic environment is very important in assessing their transport behaviour in a reactor coolant system, and the effectiveness of measures to limit radioactive contamination of the coolant system. The formation of chromium oxide nanoparticles by gamma radiolysis of CrVI (aq) (CrO42- or Cr2O72-) solutions was investigated as a function of pH and CrVI (aq) concentration using a range of chemical and particle analysis techniques. The results show that CrVI (aq) is reduced to less soluble CrIII species by reducing radiolysis products (e.g., .eaq-). These insoluble CrIII species provide nucleation

  20. Current sheet formation near a hyperbolic magnetic neutral line in a variable-density plasma: An exact solution

    International Nuclear Information System (INIS)

    Current-sheet formation near a hyperbolic magnetic neutral line in the MHD model is investigated. In this model, the magnetic field lines are swept by the plasma flow toward the X-point. Effects of density-variation of the plasma are included. An exact analytic solution is given. This solution exhibits a finite-time singularity that is peculiar to the variable-density plasma case and this finite-time singularity occurs when there is a plasma density build-up near the magnetic neutral line

  1. Effects of Thaumasite Formation on the Performance of Portland-limestone Concrete Stored in Magnesium Sulfate Solution

    Institute of Scientific and Technical Information of China (English)

    GAO Lixiong; YAO Yan; WANG Ling

    2005-01-01

    The influence of thaumasite formation on the performance of Portland- limestone cement concrete stored in magnesium sulfate solution was studied. The experimental results show that the deterioration of Portlandlimestone cement concrete is higher than that of Portland cement concrete. The more the content of limestone, the more serious the deterioration of concrete, and also the lower the temperature, the earlier the deterioration of concrete. Thaumasite was detected to form in the Portland-limestone pastes when stored in 10wt% MgSO4 solution at 3- 10 ℃ and it was easy to form at lower temperatures.

  2. Complex formation in the system double charged metal cation-Stenhouse base in water-alcohol solution

    International Nuclear Information System (INIS)

    Using the method of potentiometric titration complex formation reaction of the system metal(II) salt cation (Me2+ = Fe2+, Cd2+, Hg2+, Zn2+, Mn2+, Co2+, Ni2+) Stenhouse base in water-alcohol solution has been studied. Compositions of equilibrium complexes, the constants of their formation and instability have been determined. CoCl2 x 6H2O, NiCl2 x 6H2O and Mn(NO3)2 x 6H2O have been shown to have the most stabilizing effect on Stenhouse base

  3. SRF Cavity Fabrication and Materials

    CERN Document Server

    Singer, W

    2014-01-01

    The technological and metallurgical requirements of material for highgradient superconducting cavities are described. High-purity niobium, as the preferred metal for the fabrication of superconducting accelerating cavities, should meet exact specifications. The content of interstitial impurities such as oxygen, nitrogen, and carbon must be below 10μg/g. The hydrogen content should be kept below 2μg/g to prevent degradation of the Q-value under certain cool-down conditions. The material should be free of flaws (foreign material inclusions or cracks and laminations) that can initiate a thermal breakdown. Defects may be detected by quality control methods such as eddy current scanning and identified by a number of special methods. Conventional and alternative cavity fabrication methods are reviewed. Conventionally, niobium cavities are fabricated from sheet niobium by the formation of half-cells by deep drawing, followed by trim machining and Electron-Beam Welding (EBW). The welding of half-cells is a delicate...

  4. Formation of 32P-labelled Polyphosphates in Reactor-irradiated Solutions of Orthophosphate

    DEFF Research Database (Denmark)

    Fenger, Jørgen Folkvard; Pagsberg, Palle Bjørn

    1973-01-01

    Aqueous solutions of potassium orthophosphate were reactor irradiated and analysed by electrophoresis. The resulting distributions of 32P-activity in phosphorus oxyanions resemble the ones obtained with reactor-irradiated solid phosphates. Even in dilute solutions, polymers are formed; their total...

  5. Ageing behaviour of unary hydroxides in trivalent metal salt solutions: Formation of layered double hydroxide (LDH)-like phases

    Indian Academy of Sciences (India)

    Michael Rajamathi; P Vishnu Kamath

    2000-10-01

    The hydroxides of Mg, Ni, Cu and Zn transform into layered double hydroxide (LDH)-like phases on ageing in solutions of Al or Cr salts. This reaction is similar to acid leaching and proceeds by a dissolution–reprecipitation mechanism offering a simple method of LDH synthesis, with implications for the accepted theories of formation of LDH minerals in the earth’s crust.

  6. Formation problems of solid solutions and intermetallic phases in Al-Ni system at high-intensity ion implantation

    International Nuclear Information System (INIS)

    Experimental study results are presented for microstructure and phase composition of surface alloyed layers formed in a nickel target under conditions of high-dose and high-intensity aluminium ion implantation using a vacuum-arc ion-plasma source of Raduga-5. It is established that in an ion-doped layer the formation of nanosized intermetallic phases and sol id solutions of Al-Ni system occurs, which possess high values of heat and wear resistance

  7. Formation of 32P-labelled Polyphosphates in Reactor-irradiated Solutions of Orthophosphate

    DEFF Research Database (Denmark)

    Fenger, Jørgen Folkvard; Pagsberg, Palle Bjørn

    1973-01-01

    Aqueous solutions of potassium orthophosphate were reactor irradiated and analysed by electrophoresis. The resulting distributions of 32P-activity in phosphorus oxyanions resemble the ones obtained with reactor-irradiated solid phosphates. Even in dilute solutions, polymers are formed; their total...... yield increases with the concentration of the irradiated solution and varies in a complicated way with the pH. These observations and some experiments with addition of radical scavengers indicate that oxidation of the 32P-recoils by OH-radicals is an important step in the polymerization. It is suggested...

  8. Controlling the oxygen potential to improve the densification and the solid solution formation of uranium-plutonium mixed oxides

    Science.gov (United States)

    Berzati, Ségolène; Vaudez, Stéphane; Belin, Renaud C.; Léchelle, Jacques; Marc, Yves; Richaud, Jean-Christophe; Heintz, Jean-Marc

    2014-04-01

    Diffusion mechanisms occurring during the sintering of oxide ceramics are affected by the oxygen content of the atmosphere, as it imposes the nature and the concentration of structural defects in the material. Thus, the oxygen partial pressure, p(O2), of the sintering gas has to be precisely controlled, otherwise a large dispersion in various parameters, critical for the manufacturing of ceramics such as nuclear oxides fuels, is likely to occur. In the present work, the densification behaviour and the solid solution formation of a mixed uranium-plutonium oxide (MOX) were investigated. The initial mixture, composed of 70% UO2 + 30% PuO2, was studied at p(O2) ranging from 10-15 to 10-4 atm up to 1873 K both with dilatometry and in situ high temperature X-ray diffraction. This study has shown that the initial oxides UO2+x and PuO2-x first densify during heating and then the solid solution formation starts at about 200 K higher. The densification and the formation of the solid solution both occur at a lower temperature when p(O2) increases. Based on this result, it is possible to better define the sintering atmosphere, eventually leading to optimized parameters such as density, oxygen stoichiometry and cations homogenization of nuclear ceramics and of a wide range of industrial ceramic materials.

  9. A Simple Cosmological Solution to the Higgs Instability Problem in the Chaotic Inflation and Formation of Primordial Black Holes

    CERN Document Server

    Kawasaki, Masahiro; Yanagida, Tsutomu T

    2016-01-01

    We revisit the compatibility between the chaotic inflation, which provides a natural solution to the initial condition problem, and the metastable electroweak vacuum, which is suggested by the results of LHC and the current mass measurements of top quark and Higgs boson. It is known that the chaotic inflation poses a threat to the stability of the electroweak vacuum because it easily generates large Higgs fluctuations during inflation or preheating and triggers the catastrophic vacuum decay. In this paper, we propose a simple cosmological solution in which the vacuum is stabilized during chaotic inflation, preheating and after that. This simple solution naturally predicts formation of primordial black holes. We find interesting parameter regions where the present dark matter density is provided by them. Also, the thermal leptogensis can be accommodated in our scenario.

  10. Formation of anhydrotetracycline in gamma irradiated aqueous tetracycline solutions (Preprint No. RC-12)

    International Nuclear Information System (INIS)

    Gamma radiolysis of antibiotic tetracycline in aqueous solutions has been studied under various conditions. Anhydrotetracycline, a potential toxic substance, was identified as a major radiation degradation product formed under deoxygenated conditions mainly because of H atom attack on tetracycline. (author)

  11. Singularity formation and blowup of complex-valued solutions of the modified KdV equation

    CERN Document Server

    Bona, Jerry L; Weissler, Fred B

    2012-01-01

    The dynamics of the poles of the two--soliton solutions of the modified Korteweg--de Vries equation $$ u_t + 6u^2u_x + u_{xxx} = 0 $$ are determined. A consequence of this study is the existence of classes of smooth, complex--valued solutions of this equation, defined for $-\\infty < x < \\infty$, exponentially decreasing to zero as $|x| \\to \\infty$, that blow up in finite time.

  12. Volume and accessibility of entrained (solution) methane in deep geopressured reservoirs - tertiary formations of the Texas Gulf Coast. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Gregory, A.R.; Dodge, M.M.; Posey, J.S.; Morton, R.A.

    1980-10-01

    The objective of this project was to appraise the total volume of in-place methane dissolved in formation waters of deep sandstone reservoirs of the onshore Texas Gulf Coast within the stratigraphic section extending from the base of significant hydrocarbon production (8000 ft)* to the deepest significant sandstone occurrence. The area of investigation is about 50,000 mi/sup 2/. Factors that determine the total methane resource are reservoir bulk volume, porosity, and methane solubility; the latter is controlled by the temperature, pressure, and salinity of formation waters. Regional assessment of the volume and the distribution of potential sandstone reservoirs was made from a data base of 880 electrical well logs, from which a grid of 24 dip cross sections and 4 strike cross sections was constructed. Solution methane content in each of nine formations or divisions of formations was determined for each subdivision. The distribution of solution methane in the Gulf Coast was described on the basis of five reservoir models. Each model was characterized by depositional environment, reservoir continuity, porosity, permeability, and methane solubility.

  13. Effect of the position of the condensed ring with pyridine on the possibility of formation of polynuclear V(3) complexes in alcohol solution

    International Nuclear Information System (INIS)

    The system VCl3-β,γ-benzopyridine (isoquinoline) in ethanol solution was examined by spectrophotometric, conductometric and magnetic methods. The formation of a violet, binuclear [V2(isoquin)6Cl5]+ type complex and a green, polynuclear complex of an analogous formula was found in solution and in the solid phase, respectively. The effect of the condensed ring position on the formation of polynuclear V(3) complexes in alcohol solutions is discussed. 5 figs., 6 tabs., 12 refs. (author)

  14. Finite-Difference Solutions of the Alternate Turbopump Development High-Pressure Oxidizer Turbopump Pump-End Ball-Bearing Cavity Flows

    Science.gov (United States)

    Benjamin, Theodore G.; Garcia, Roberto; Mcconnaughey, Paul K.; Wang, Ten-See; Vu, Bruce T.; Dakhoul, Youssef

    1993-01-01

    These analyses were undertaken to aid in the understanding of flow phenomena in the Alternate Turbopump Development (ATD) High-pressure Oxidizer Turbopump (HPOTP) Pump-end ball bearing (PEBB) cavities and their roles in turbopump vibration initiation and bearing distress. This effort was being performed to provide timely support to the program in a decision as to whether or not the program should be continued. In the first case, it was determined that a change in bearing through flow had no significant effect on axial preload. This was a follow-on to a previous study which had resulted in a redesign of the bearing exit cavity which virtually eliminated bearing axial loading. In the second case, a three-dimensional analysis of the inner-race-guided cage configuration was performed so as to determine the pressure distribution on the outer race when the shaft is 0.0002 inches off-center. The results indicate that there is virtually no circumferential pressure difference caused by the offset to contribute to bearing tilt. In the third case, axisymmetric analyses were performed on an outer-race guided cage configuration to determine the magnitude of tangential flow entering the bearing. The removed-shoulder case was analyzed as was the static diverter case. A third analysis where the preload spring was shielded by a sheet of metal for the baseline case was also performed. It was determined that the swirl entering the bearing was acceptable and the project decided to use the outer-race-guided cage configuration. In the fourth case, more bearing configurations were analyzed. These analyses included thermal modeling so as to determine the added benefit of injecting colder fluid directly onto the bearing inner-race contact area. The results of these analyses contributed to a programmatic decision to include coolant injection in the design.

  15. Cavity magnomechanics

    Science.gov (United States)

    Zhang, Xufeng; Zou, Changling; Jiang, Liang; Tang, Hong X.

    Mechanical oscillators have been recently widely utilized to couple with optical and microwave photons in a variety of hybrid quantum systems, but they all lack the tunability. The magnetostrictive force provides an alternative mechanism to allow phonon to couple with a different type of information carrier-magnon, the collective excitation of magnetization whose frequency can be tuned by a bias magnetic field. Here, we demonstrate an intriguing hybrid system that consists of a magnonic, a mechanical, and a microwave resonator. The magnon-phonon interaction results in hallmark coherent phenomena such as magnomechanically induced transparency/absorption and magnomechanical parametric amplification. The magnetic field dependence of magnon provides our system with unprecedented tunability. Moreover, the great flexibility of our system allows us to achieve triple resonance among magnon, phonon and photon, which drastically enhances the magnomechanical interaction. Our work demonstrates the fundamental principle of cavity magnetomechanics, opening up great opportunities in various applications, such as tunable microwave filter and amplifier, long-lifetime quantum memories, microwave-to-optics conversion.

  16. Solubility and colloid formation of Th(IV) in concentrated NaCl and MgCl2 solution

    International Nuclear Information System (INIS)

    The solubility of crystalline ThO2(cr) and amorphous hydrated Th(IV) oxyhydroxide ThOn(OH)4-2n.xH2O(am) has been measured in dilute to concentrated NaCl and MgCl2 solutions equilibrated with magnesium hydroxide or hydroxychloride at 22 ± 2 C. The contributions of colloids to the total thorium concentrations observed in both over- and undersaturation experiments with amorphous Th(IV) precipitates have been analysed by ultracentrifugation. The solubility increasing effect of long-time stable Th(IV) eigencolloids, previously investigated in 0.5 M NaCl solutions, is also observed in concentrated 5 M NaCl. Ionic strength and chloride concentration have no effect on the stability of these hydrophilic Th(IV) oxyhydroxide eigencolloids, which are the predominant species in solution. They cause relatively high total thorium concentration in neutral to alkaline steady state solutions, independent of ionic strength: log[Th]tot ∼ log[Th]coll = -6.3 ± 0.5. In concentrated MgCl2 solutions saturated with magnesium hydroxychloride colloids, the formation of pseudocolloids, i.e., Th(IV) sorbed onto Mg2(OH)3Cl.4H2O(coll), leads to a further increase of the total thorium concentration up to 10-5 M. The present results are discussed with regard to maximum Th(IV) and Pu(IV) concentrations in performance assessment calculations. (orig.)

  17. Controlled formation of 3D CdS nanocrystal superlattices in solution

    International Nuclear Information System (INIS)

    Highly ordered 3D superlattices comprised of monodisperse CdS nanocrystals are formed rapidly in solution using a simple procedure. Control over the instigation of the superlattice crystallization process is demonstrated by adjusting the concentration of sulfur in solution. Transmission electron microscopy shows that the CdS nanocrystals are 7 nm in size and form well-ordered structures. Selected area electron diffraction of the superlattices reveals that the CdS nanocrystals have their crystal axes partially aligned. This is further confirmed using a fast Fourier transform analysis of high-resolution transmission electron micrographs

  18. Dynamics of Magnesite Formation at Low-Temperature and High pCO2 in Aqueous Solution

    Energy Technology Data Exchange (ETDEWEB)

    Qafoku, Odeta; Dixon, David A.; Rosso, Kevin M.; Schaef, Herbert T.; Bowden, Mark E.; Arey, Bruce W.; Felmy, Andrew R.

    2015-09-17

    Like many metal carbonate minerals, despite conditions of supersaturation, precipitation of magnesite from aqueous solution is kinetically hindered at low temperatures, for reasons that remain poorly understood. The present study examines precipitation products from reaction of Mg(OH)2 in aqueous solutions saturated with supercritical CO2 at high pressures (90 atm and 110 atm) and low temperatures (35 °C and 50 °C). Traditional bulk characterization (X-ray diffraction) of the initial solid formed indicated the presence of hydrated magnesium carbonates (hydromagnesite and nesquehonite), thermodynamically metastable phases that were found to slowly react during ageing to the more stable anhydrous form, magnesite, at temperatures as low as 35 °C (135-140 days) and at a faster rate at 50 °C (56 days). Undetected by bulk measurements, detailed examination of the precipitates by scanning electron microscopy (SEM) showed that magnesite is present as a minor component at relatively early reaction times (7 days) at 50 °C. In addition to magnesite dominating the solid phases over time, we find that mangesite nucleation and growth occurs more quickly with increasing partial pressure of CO2, and in electrolyte solutions with high bicarbonate content. Furthermore, formation of magnesite was found to be enhanced in sulfate-rich solutions, compared to chloride-rich solutions. We speculate that much of this behavior is possibly due to sulfate serving as sink of protons generated during carbonation reactions. These results support the importance of integrating magnesite as an equilibrium phase in reactive transport calculations of the effects of carbon dioxide sequestration on subsurface formations at long time scales.

  19. The formation of ZnO-based coatings from solutions containing high-molecular polyvinylpyrrolidone

    Science.gov (United States)

    Evstrop'ev, S. K.; Soshnikov, I. P.; Khrebtov, A. I.

    2016-05-01

    A method for deposition of transparent nanosize ZnO-based coatings on the glass surface from solutions containing high-molecular polyvinylpyrrolidone is described. The method can be used to form transparent homogeneous coatings based on ZnO with an increased energy gap width. It does not require any intricate technological equipment.

  20. The mechanism of the initial step of germanosilicate formation in solution: a first-principles molecular dynamics study.

    Science.gov (United States)

    Trinh, Thuat T; Rozanska, Xavier; Delbecq, Françoise; Tuel, Alain; Sautet, Philippe

    2016-06-01

    The condensation reactions between Ge(OH)4 and Si(OH)4 units in solution are studied to understand the mechanism and stable species during the initial steps of the formation process of Ge containing zeolites under basic conditions. The free energy of formation of (OH)3Ge-O-Ge-(OH)2O(-), (OH)3Si-O-Si-(OH)2O(-), (OH)3Ge-O-Si-(OH)2O(-) and (OH)3Si-O-Ge-(OH)2O(-) dimers is calculated with ab initio molecular dynamics and thermodynamic integration, including an explicit description of the water solvent molecules. Calculations show that the attack of the conjugated base (Ge(OH)3O(-) and Si(OH)3O(-)) proceeds with a smaller barrier at the Ge center. In addition, the formation of the pure germanate dimer is more favorable than that of the germano-silicate structure. These results explain the experimental observation of Ge-Ge and Si-Ge dimer species in solutions, with a few Si-Si ones. PMID:27172391

  1. Impact of sodium polyacrylate on the amorphous calcium carbonate formation from supersaturated solution.

    Science.gov (United States)

    Liu, J; Pancera, S; Boyko, V; Gummel, J; Nayuk, R; Huber, K

    2012-02-21

    A detailed in situ scattering study has been carried out on the formation of amorphous calcium carbonate (ACC) particles modulated by the presence of small amounts of sodium polyacrylate chains. The work is aiming at an insight into the modulation of ACC formation by means of two polyacrylate samples differing in their molecular weight by a factor of 50. The ACC formation process was initiated by an in situ generation of CO(3)(2-) ions via hydrolysis of 10 mM dimethylcarbonate in the presence of 10 mM CaCl(2). Analysis of the formation process by means of time-resolved small-angle X-ray and light scattering in the absence of any additives provided evidence for a monomer addition mechanism for the growth of ACC particles. ACC formation under these conditions sets in after a lag-period of some 350 s. In the presence of sodium polyacrylate chains, calcium polyacrylate aggregates are formed during the lag-period, succeeded by a modulated ACC growth in a second step. The presence of anionic polyacrylate chains changed the shape of the growing particles toward loose and less homogeneous entities. In the case of low amounts (1.5-7.5 mg/L) of the long chain additive with 97 kDa, the size of the aggregates is comparable to the size of the successively formed hybrid particles. No variation of the lag-period has been observed in this case. Use of the short chain additive with 2 kDa enabled increase of the additive concentration up to 100 mg/L and resulted in a significant increase of the lag-period. This fact, together with the finding that the resulting hybrid particles remained stable in the latter case, identified short chain sodium polyacrylates as more efficient modulators than long chain polyacrylates. PMID:22256962

  2. Cocrystal formation in solution: Inducing phase transition by manipulating the amount of cocrystallizing agent

    Science.gov (United States)

    Gagniere, Emilie; Mangin, Denis; Puel, François; Valour, Jean-Pierre; Klein, Jean-Paul; Monnier, Olivier

    2011-02-01

    The purpose of this work was to assess the possibility of inducing solution mediated phase transition (SMPT) by manipulating the amount of the cocrystallizing agent. The cocrystal, composed of an active pharmaceutical ingredient (carbamazepine, CBZ) and its cocrystallizing agent (a vitamin—nicotinamide, NCT), was selected as a model compound. Batch experiments were performed in a stirred vessel. The solute concentrations of both CBZ and NCT were monitored using in situ ATR-FTIR spectroscopy. The introduction of NCT in dry form allowed a shift in the phase diagram, leading to an SMPT from CBZ crystals toward cocrystals. The concentration profiles gave information on the phase transition kinetics, i.e., the kinetics of nucleation, growth and dissolution mechanisms of the solid phases involved. Several situations were analyzed. This procedure could also be used to correct a process deviation that led to CBZ crystals instead of cocrystals.

  3. Cavities in molecular liquids and the theory of hydrophobic solubilities

    Science.gov (United States)

    Pohorille, A.; Pratt, L. R.; MacElroy, R. (Principal Investigator)

    1990-01-01

    Thermal configurational data on neat liquids are used to obtain the work of formation of hard spherical cavities of atomic size in six molecular solvents: n-hexane, n-dodecane, n-undecyl alcohol, chloroform, carbon tetrachloride, and water. These results are used to test a recent suggestion that the differences between nonaqueous solvents and liquid water in solvation of inert gases are not principally due to the hydrogen-bonded structure of liquid water but rather to the comparatively small size of the water molecule. The frequencies of occurrence of cavities in liquid water can be meaningfully distinguished from those in the organic solvents. Liquid water has a larger fractional free volume, but that free volume is distributed in smaller packets. With respect to cavity work, water is compared to a solvent of the same molecular density and composed of hard spheres of the same size as the water molecule. That comparison indicates that the hard-sphere liquid finds more ways to configure its free volume in order to accommodate an atomic solute of substantial size and thus, would be more favorable solvent for inert gases. The scaled particle model of inert gas solubility in liquid water predicts cavity works 20% below the numerical data for TIP4P water at 300 K and 1.0 g/cm3 for cavity radii near 2.0 angstroms. It is argued that the sign of this difference is just the sign that ought to be expected and that the magnitude of this difference measures structural differences between water and the directly comparable hard-sphere liquid. In conjunction with previous data, these results indicate that atomic sized cavities should be considered submacroscopic.

  4. Biomimetic apatite formation on different polymeric microspheres modified with calcium silicate solutions

    OpenAIRE

    Leonor, I. B.; Balas, F.; Kawashita, M.; Reis, R. L.; T Kokubo; Nakamura, T

    2006-01-01

    Bioactive polymeric microspheres can be produced by pre-coating them with a calcium silicate solution and the subsequent soaking in a simulated body fluid (SBF). Such combination should allow for the development of bioactive microspheres for several applications in the medical field including tissue engineering. In this work, three types of polymeric microspheres with different sizes were used: (i) ethylene-vinyl alcohol co-polymer (20-30 'm), (ii) polyamide 12 (10-30 'm) and (...

  5. Observation and characterization of cavity Rydberg polaritons

    Science.gov (United States)

    Ningyuan, Jia; Georgakopoulos, Alexandros; Ryou, Albert; Schine, Nathan; Sommer, Ariel; Simon, Jonathan

    2016-04-01

    We experimentally demonstrate the emergence of a robust quasiparticle, the cavity Rydberg polariton, when an optical cavity photon hybridizes with a collective Rydberg excitation of a laser-cooled atomic ensemble. Free-space Rydberg polaritons have recently drawn intense interest as tools for quantum information processing and few-body quantum science. Here, we explore the properties of their cavity counterparts in the single-particle sector, observing an enhanced lifetime and slowed dynamics characteristic of cavity dark polaritons. We measure the range of cavity frequencies over which the polaritons persist, corresponding to the spectral width available for polariton quantum dynamics, and the speed limit for quantum information processing. Further, we observe a cavity-induced suppression of inhomogeneous broadening channels and demonstrate the formation of Rydberg polaritons in a multimode cavity. In conjunction with recent demonstrations of Rydberg-induced cavity nonlinearities, our results point the way towards using cavity Rydberg polaritons as a platform for creating high-fidelity photonic quantum materials and, more broadly, indicate that cavity dark polaritons offer enhanced stability and control uniquely suited to optical quantum information processing applications beyond the Rydberg paradigm.

  6. Influence of shear on globule formation in dilute solutions of flexible polymers

    Science.gov (United States)

    Radhakrishnan, Rangarajan; Underhill, Patrick T.

    2015-04-01

    Polyelectrolytes, polymers in poor solvents, polymers mixed with particles, and other systems with attractions and repulsions show formation of globules/structures in equilibrium or in flow. To study the flow behavior of such systems, we developed a simple coarse-grained model with short ranged attractions and repulsions. Polymers are represented as charged bead-spring chains and they interact with oppositely charged colloids. Neglecting hydrodynamic interactions, we study the formation of compact polymer structures called globules. Under certain conditions, increase in shear rate decreases the mean first passage time to form a globule. At other conditions, shear flow causes the globules to breakup, similar to the globule-stretch transition of polymers in poor solvents.

  7. Cavity Solitons in VCSEL Devices

    Directory of Open Access Journals (Sweden)

    S. Barbay

    2011-01-01

    Full Text Available We review advances on the experimental study of cavity solitons in VCSELs in the past decade. We emphasize on the design and fabrication of electrically or optically pumped broad-area VCSELs used for CSs formation and review different experimental configurations. Potential applications of CSs in the field of photonics are discussed, in particular the use of CSs for all-optical processing of information and for VCSELs characterization. Prospects on self-localization studies based on vertical cavity devices involving new physical mechanisms are also given.

  8. A Numerical Renormalization Solution for Self-Similar Cosmic Structure Formation

    CERN Document Server

    Couchman, H M P

    1997-01-01

    We present results of a numerical renormalization approximation to the self- similar growth of clustering of pressureless dust out of a power-law spectrum of primeval Gaussian mass density fluctuations (index n) in an Einstein-de Sitter cosmological model. The self-similar two-point correlation function, xi, seems to be well established. The renormalization solutions for xi show a satisfying insensitivity to the parameters in the method, and at n=-1 and 0 are close to the Hamilton et al. formula for interpolation between the large-scale perturbative limit and stable small-scale clustering. The solutions are tested by comparing the mean relative peculiar velocity of particle pairs and the velocity derived from xi under the assumption of self-similar evolution. Both the renormalization and a comparison conventional N-body solution are in reasonable agreement with the test, although the conventional approach does slightly better at large separations and the renormalization approach slightly better at small sepa...

  9. Late formation of singularities in solutions to the Navier-Stokes equations

    Science.gov (United States)

    Ohkitani, Koji

    2016-01-01

    We study how late the first singularity can form in solutions of the Navier-Stokes equations and estimate the size of the potentially dangerous time interval, where it can possibly appear. According to Leray (1934), its size is estimated as O({R}8) when normalized by the local existence time, for a general blowup of the enstrophy Q(t)≥slant \\frac{c{ν }3/2}{{({t}*-t)}1/2} at t={t}*. Here R={(E(0)Q(0))}1/4/ν is the Reynolds number defined with initial energy E(0) and enstrophy Q(0). Applying dynamic scaling transformations, we give a general estimate parameterized by the behaviour of the scaled enstrophy. In particular, we show that the size is reduced to O({R}4), for a class of type II blow up of the form Q(t)≥slant \\frac{{c}\\prime {ν }3/2}{{({t}*-t)}\\frac{1{2}+0}}. On the basis on the structure theorem of Leray (1934), we note that the self-similar and asymptotically self-similar blowup are ruled out for any singularities of weak solutions. We also apply the dynamic scaling to weak solutions with more than one singularities to show that the size is estimated as O({R}4) for the type II blowup above.

  10. From solid solution to cluster formation of Fe and Cr in α-Zr

    Science.gov (United States)

    Burr, P. A.; Wenman, M. R.; Gault, B.; Moody, M. P.; Ivermark, M.; Rushton, M. J. D.; Preuss, M.; Edwards, L.; Grimes, R. W.

    2015-12-01

    To understand the mechanisms by which the re-solution of Fe and Cr additions increase the corrosion rate of irradiated Zr alloys, the solubility and clustering of Fe and Cr in model binary Zr alloys was investigated using a combination of experimental and modelling techniques - atom probe tomography (APT), x-ray diffraction (XRD), thermoelectric power (TEP) and density functional theory (DFT). Cr occupies both interstitial and substitutional sites in the α-Zr lattice; Fe favours interstitial sites, and a low-symmetry site that was not previously modelled is found to be the most favourable for Fe. Lattice expansion as a function of Fe and Cr content in the α-Zr matrix deviates from Vegard's law and is strongly anisotropic for Fe additions, expanding the c-axis while contracting the a-axis. Matrix content of solutes cannot be reliably estimated from lattice parameter measurements, instead a combination of TEP and APT was employed. Defect clusters form at higher solution concentrations, which induce a smaller lattice strain compared to the dilute defects. In the presence of a Zr vacancy, all two-atom clusters are more soluble than individual point defects and as many as four Fe or three Cr atoms could be accommodated in a single Zr vacancy. The Zr vacancy is critical for the increased apparent solubility of defect clusters; the implications for irradiation induced microstructure changes in Zr alloys are discussed.

  11. Investigation on the formation of Cu–Fe nano crystalline super-saturated solid solution developed by mechanical alloying

    International Nuclear Information System (INIS)

    Highlights: ► The deformation of the mechanically alloyed Cu–Fe powder is anisotropic. ► The Rietveld method is more proper and results in smaller crystallite size than the Scherer and Williamson–Hall methods. ► A dual phase super saturated solid solution achieved after 96 h of milling of the mixtures with 30, 50 and 70 wt.% of Iron. ► A final proportion of approximately 85% FCC and 15% BCC structure obtained in all of the applied compositions. - Abstract: In this study, the formation of super saturated solid solution in the binary Cu–Fe system was investigated. Three powder blends with 30, 50 and 70 wt.% of Fe were milled for different times to 96 h. The variations of lattice parameter and inter-planar spacing were calculated and analyzed using X-ray diffraction analysis (XDA). The anisotropy of lattice deformation in the FCC phase was studied and the obtained results were compared to milled pure Cu powder. Furthermore, crystallite size was calculated using Scherer formula in comparison with Rietveld full profile refinement method. Considering the previous studies about the formation of non-equilibrium FCC and BCC phases, the phase evolution has been discussed and the proportion of each phase was calculated using Rietveld refinement method. Supplementary studies on the evolution of microstructure and formation of solid solution were carried out using high resolution transmission electron microscopy (HRTEM). Finally, high angle annular dark field (HAADF) imaging was utilized to find out the level of homogeneity in the resulting phases. While true alloying takes place in each phase, the final structure consists of both FCC and BCC nano-crystallites.

  12. Nano-silver Colloidal Solution Formation by a Simple and Green Method

    Directory of Open Access Journals (Sweden)

    Hamid Reza Ghorbani

    2014-09-01

    Full Text Available Silver nanoparticles were obtained in aqueous medium, at room temperature, by simple and low cost route. The synthesis involves the use of silver nitrate, polyvinylpyrrolidone (pvp, dextrose and water as the silver precursor, stabilizing agent, reducing agent and solvent respectively. In order to identify and analyze nanoparticles, UV – Vis spectroscopy, transitional electron microscopy (TEM, and dynamic light scattering (DLS were used. All data showed evidence for the formation of silver nanoparticles, with the size of 6–12 nm.

  13. Printing holes by a dewetting solution enables formation of a transparent conductive film.

    Science.gov (United States)

    Layani, Michael; Berman, Ruth; Magdassi, Shlomo

    2014-11-12

    We present hereby a general approach for rapid fabrication of large scale, patterned transparent conductive coatings composed of nanoparticles. The approach is based on direct formation of "2D holes" with controllable diameter onto a thin film composed of metal nanoparticles. The holes are formed by inkjet printing a dewetting aqueous liquid, which pushes away the metal nanoparticles, thus forming a transparent array of interconnected conductive rings. PMID:25331032

  14. Reversible formation of gold nanoparticle–surfactant composite assemblies for the preparation of concentrated colloidal solutions

    OpenAIRE

    Shalkevich, Natallia; Shalkevich, Andrey; Si-Ahmed, Lynda; Bürgi, Thomas

    2010-01-01

    We have developed a simple method for the preparation of nearly mono-dispersed stable gold colloids with a fairly high concentration using a two step procedure. First we synthesize citrate capped gold nanoparticles and then exchange the citrate ions with triethyleneglycolmono-11-mercaptoundecylether (EGMUDE). This leads to the immediate precipitation and formation of composite assemblies. The gold nanoparticles were successfully self-redispersed after a few days. The prepared gold colloid can...

  15. The spectroscopic study of complex formation of rhodamine and oxazine dyes with rare-earth elements in solution

    International Nuclear Information System (INIS)

    The results of spectroscopic study of a complex formation of rhodamine and oxazine dyes with rare-earth ions in solutions are presented. Rhodamine dyes in the lactone form and oxazine dyes in the base form are found to form complex compounds of different compositions with metal ion in solution with cations of rare-earth metal. Besides, the spectral-luminescent characteristics of rhodamine and oxazine dyes, specific to their cationic form are restored. Methods of iso molar series and of the saturation curve the composition and stability of the formed complexes are determined. The monovalent metal ions form complexes with the dye molecules of composition 1:1, the divalent ions - 2:1 composition, and the trivalent ions - 3:1. (authors)

  16. Formation of magnetite (Fe3O4)in aqueous media and properties of the interface magnetite/solution

    International Nuclear Information System (INIS)

    The formation of Fe3O4 particles in aqueous media and the properties of the Fe3O4/aqueous solution interface are studied. This system is of particular interest in nuclear reactor chemistry, since Fe3O4 was identified as the main component of the corrosion products of nuclear power plants cooled with pressurized water, of the Atucha I and II, and Embalse type. Four methods for the synthesis of Fe3O4 are described: a) controlled oxidation of Fe(OH)2 in the presence of NaNO3 at 25 deg C; b) controlled oxidation of Fe(OH)2 in the presence of NaNO3 and N2H4 and at 100 deg C; c) alkalinization of a F2+ and Fe3+ solutions at 80 deg C; d) simultaneous oxidation and alkalinization of a Fe2+. The interfacial properties of Fe3O4 particles suspended in aqueous solutions of indifferent electrolytes are described. These properties are essential for the activity transport associated with the corrosion products. Finally, the adsorption of H3BO3, Hsub(n)PO4sup(n-3) and n Co(II) in the Fe3O4/solution interface at 30 deg C. It is concluded that the adsorbed species are chemically bonded to surface metal ions. (M.E.L.)

  17. Hydroxyl radical-induced strand break formation of poly(U) in anoxic solution. Effect of dithiothreitol and tetranitromethane

    International Nuclear Information System (INIS)

    The role of dithiothreitol (DTT) and tetranitromethane (TNM) on the yields of γ-radiation-induced strand break formation in polyuridylic acid (poly(U)) was studied in anoxic aqueous solutions at neutral pH by low-angle laser light-scattering. From G(single-strand breaks) as a function of DTT concentration it follows that two different processes lead to OH radical-induced single-strand break (ssb) formation. Only one of the two processes, which accounts for 80% of the ssb formation, is inhibited by DTT, the other one, 20% is not inhibited. The 'repair' process is attributed to H-donation to the C-6-yl radical of the uracil moiety. The C-6-yl radical is produced by OH addition to the C-5 position of the uracil moiety. It follows that the sugar radicals, in contrast to earlier suggestions, do not seem to be repaired by DTT at the low concentrations used. The strand break formation not inhibited by DTT is induced by radicals other than the uracil-6-yl radical, e.g. the uracil-5-yl or the OH radicals reacting with the sugar moiety. The strong reduction of G(ssb) from 2.3 to 0.2 on addition of TNM is also discussed. (author)

  18. Hydrodynamic Drag on Streamlined Projectiles and Cavities

    KAUST Repository

    Jetly, Aditya

    2016-04-19

    The air cavity formation resulting from the water-entry of solid objects has been the subject of extensive research due to its application in various fields such as biology, marine vehicles, sports and oil and gas industries. Recently we demonstrated that at certain conditions following the closing of the air cavity formed by the initial impact of a superhydrophobic sphere on a free water surface a stable streamlined shape air cavity can remain attached to the sphere. The formation of superhydrophobic sphere and attached air cavity reaches a steady state during the free fall. In this thesis we further explore this novel phenomenon to quantify the drag on streamlined shape cavities. The drag on the sphere-cavity formation is then compared with the drag on solid projectile which were designed to have self-similar shape to that of the cavity. The solid projectiles of adjustable weight were produced using 3D printing technique. In a set of experiments on the free fall of projectile we determined the variation of projectiles drag coefficient as a function of the projectiles length to diameter ratio and the projectiles specific weight, covering a range of intermediate Reynolds number, Re ~ 104 – 105 which are characteristic for our streamlined cavity experiments. Parallel free fall experiment with sphere attached streamlined air cavity and projectile of the same shape and effective weight clearly demonstrated the drag reduction effect due to the stress-free boundary condition at cavity liquid interface. The streamlined cavity experiments can be used as the upper bound estimate of the drag reduction by air layers naturally sustained on superhydrophobic surfaces in contact with water. In the final part of the thesis we design an experiment to test the drag reduction capacity of robust superhydrophobic coatings deposited on the surface of various model vessels.

  19. Crab Cavity Development

    CERN Document Server

    Calaga, R; Burt, G; Ratti, A

    2015-01-01

    The HL-LHC upgrade will use deflecting (or crab) cavities to compensate for geometric luminosity loss at low β* and non-zero crossing angle. A local scheme with crab cavity pairs across the IPs is used employing compact crab cavities at 400 MHz. Design of the cavities, the cryomodules and the RF system is well advanced. The LHC crab cavities will be validated initially with proton beam in the SPS.

  20. Temperature induced complex formation-deformation behavior of collagen model peptides and polyelectrolytes in aqueous solution

    OpenAIRE

    Terao, Ken; Kanenaga, Ryoko; Yoshida, Tasuku; Mizuno, Kazunori; Bächinger, Hans Peter

    2015-01-01

    Since the triple-helical collagen model peptides with a free N-terminus have three cationic groups at one end, it may have strong interactions with polyelectrolytes. In this study, complex formation behavior was investigated for sodium carboxymethyl amylose (NaCMA) + H-(Pro-Pro-Gly)10-OH (PPG10), a collagen model peptide, in aqueous NaCl with ionic strength of 10 mM and 100 mM by means of small-angle X-ray scattering (SAXS) and circular dichroism at different temperatures. The previously repo...

  1. Separation of californium from actinides and lanthanides in aqueous solution by electrochemical formation of amalgams

    International Nuclear Information System (INIS)

    The electrochemical reduction of transneptunium elements (Pu to Cf) and rare earths (Eu, Tm) from aqueous complexing solutions to amalgams was studied over a wide range of cathodic potentials in order to achieve optimal separation of californium. The reduction in acetate media (pH 4.5-4.6) at potentials around -1.7 to -1.9 V1 leads to a quantitative extraction of californium into the mercury phase, while more negative potentials are required for the reduction of the lighter transuranium elements and of the lanthanides. Hence, the optimal conditions for the separation of californium from the investigated actinides and lanthanides were determined. Separation factors α between 25 and 90 were found except in the case of Cf/Eu, where poor values (α varying from 7 to 12) were observed. More negative cathodic potentials decrease the selectivity of the reduction process. A similar study with lithium citrate solutions (pH ∝6) shows that satisfactory separation of californium from lighter and heavier actinides is achievable. A separation factor of 88 is obtained for Cf/Am at -1.98 V. The anodic stripping of mixed amalgams (Pu, Am, Cm, Bk, Tm and Cf) Hg in nitric and acetic acid soultions at potentials ranging from +0.1 to -0.7 V proceeds slowly and proved to be ineffective for the separation of californium from light actinides under conditions described. (orig.)

  2. Formation of hydrated layers in PMMA thin films in aqueous solution

    Science.gov (United States)

    Akers, Peter W.; Nelson, Andrew R. J.; Williams, David E.; McGillivray, Duncan J.

    2015-10-01

    Neutron reflectometry (NR) measurements have been made on thin (70-150 Å) poly(methylmethacrylate) (PMMA) films on Si/SiOx substrates in aqueous conditions, and compared with parameters measured using ellipsometry and X-Ray reflectometry (XRR) on dry films. All techniques show that the thin films prepared using spin-coating techniques were uniform and had low roughness at both the silicon and subphase interfaces, and similar surface energetics to thicker PMMA films. In aqueous solution, NR measurements at 25 °C showed that PMMA forms a partially hydrated layer at the SiOx interface 10 Å under the film, while the bulk film remains intact and contains around 4% water. Both the PMMA film layer and the sublayer showed minimal swelling over a period of 24 h. At 50 °C, PMMA films in aqueous solution roughen and swell, without loss of PMMA material at the surface. After cooling back to 25 °C, swelling and roughening increases further, with loss of material from the PMMA layer.

  3. THE NONISOTHERMAL STAGE OF MAGNETIC STAR FORMATION. I. FORMULATION OF THE PROBLEM AND METHOD OF SOLUTION

    International Nuclear Information System (INIS)

    We formulate the problem of the formation and subsequent evolution of fragments (or cores) in magnetically supported, self-gravitating molecular clouds in two spatial dimensions. The six-fluid (neutrals, electrons, molecular and atomic ions, positively charged, negatively charged, and neutral grains) physical system is governed by the radiation, nonideal magnetohydrodynamic equations. The magnetic flux is not assumed to be frozen in any of the charged species. Its evolution is determined by a newly derived generalized Ohm's law, which accounts for the contributions of both elastic and inelastic collisions to ambipolar diffusion and Ohmic dissipation. The species abundances are calculated using an extensive chemical-equilibrium network. Both MRN and uniform grain size distributions are considered. The thermal evolution of the protostellar core and its effect on the dynamics are followed by employing the gray flux-limited diffusion approximation. Realistic temperature-dependent grain opacities are used that account for a variety of grain compositions. We have augmented the publicly available Zeus-MP code to take into consideration all these effects and have modified several of its algorithms to improve convergence, accuracy, and efficiency. Results of magnetic star formation simulations that accurately track the evolution of a protostellar fragment from a density ≅103 cm-3 to a density ≅1015 cm-3, while rigorously accounting for both nonideal MHD processes and radiative transfer, are presented in a separate paper.

  4. Evidence for the Formation of Benzacridine Derivatives in Alkaline-Treated Sunflower Meal and Model Solutions

    Directory of Open Access Journals (Sweden)

    Verena Bongartz

    2016-01-01

    Full Text Available Sunflower extraction meal (SEM is an economically interesting protein source. During alkaline extraction of proteins, the presence of chlorogenic acid (CQA in the meal gives rise to the formation of o-quinones. Reactions with nucleophiles present in proteins can lead to green discoloration. Although such reactions have been known for a long time, there is a lack of information on the chemical nature of the reaction products. SEM and model systems consisting of amino acids and CQA were subjected to alkaline treatment and, for comparison, to oxidation of CQA by polyphenoloxidase (PPO. Several green trihydroxy benzacridine (TBA derivatives were tentatively identified in all samples by UHPLC-DAD-MS/MS. Surprisingly, in alkaline-treated samples of particular amino acids as well as in SEM, the same six TBA isomers were detected. In contrast, the enzymatically oxidized samples resulted in only three TBA derivatives. Contrary to previous findings, neither peptide nor amino acid residues were attached to the resultant benzacridine core. The results indicate that the formation of TBA derivatives is caused by the reaction between CQA quinones and free NH2 groups. Further research is necessary to elucidate the structure of the addition products for a comprehensive evaluation of food and feed safety aspects.

  5. Evidence for the Formation of Benzacridine Derivatives in Alkaline-Treated Sunflower Meal and Model Solutions.

    Science.gov (United States)

    Bongartz, Verena; Brandt, Lisa; Gehrmann, Mai Linh; Zimmermann, Benno F; Schulze-Kaysers, Nadine; Schieber, Andreas

    2016-01-01

    Sunflower extraction meal (SEM) is an economically interesting protein source. During alkaline extraction of proteins, the presence of chlorogenic acid (CQA) in the meal gives rise to the formation of o-quinones. Reactions with nucleophiles present in proteins can lead to green discoloration. Although such reactions have been known for a long time, there is a lack of information on the chemical nature of the reaction products. SEM and model systems consisting of amino acids and CQA were subjected to alkaline treatment and, for comparison, to oxidation of CQA by polyphenoloxidase (PPO). Several green trihydroxy benzacridine (TBA) derivatives were tentatively identified in all samples by UHPLC-DAD-MS/MS. Surprisingly, in alkaline-treated samples of particular amino acids as well as in SEM, the same six TBA isomers were detected. In contrast, the enzymatically oxidized samples resulted in only three TBA derivatives. Contrary to previous findings, neither peptide nor amino acid residues were attached to the resultant benzacridine core. The results indicate that the formation of TBA derivatives is caused by the reaction between CQA quinones and free NH2 groups. Further research is necessary to elucidate the structure of the addition products for a comprehensive evaluation of food and feed safety aspects. PMID:26784152

  6. Protostar Formation in Magnetic Molecular Clouds beyond Ion Detachment: II. Typical Axisymmetric Solution

    CERN Document Server

    Tassis, K; Tassis, Konstantinos; Mouschovias, Telemachos Ch.

    2007-01-01

    We follow the ambipolar-diffusion--driven formation and evolution of a fragment in a magnetically supported molecular cloud, until a hydrostatic protostellar core forms at its center. This problem was formulated in Paper I. We determine the density, velocity and magnetic field as functions of space and time, and the contribution of ambipolar diffusion and Ohmic dissipation to the resolution of the magnetic flux problem of star formation. The issue of whether the magnetic field ever decouples from the (neutral) matter is also addressed. We also find that the electrons do not decouple from the field lines before thermal ionization becomes important and recouples the magnetic field to the neutral matter. Ohmic dissipation becomes more effective than ambipolar diffusion as a flux reduction mechanism only at the highest densities (a few times 10^12 particles per cubic cm). In the high-density central parts of the core, the magnetic field acquires an almost spatially uniform structure, with a value that, at the end...

  7. Effect of solution pH on CO: formate formation rates during electrochemical reduction of aqueous CO2 at Sn cathodes

    International Nuclear Information System (INIS)

    The dependence of the molar ratios of CO:formate products formed by electrochemical reduction of CO2 at Sn electrodes was studied in aqueous buffer solutions as a function of pH, with values of those ratios ranging from 1 to 0.15 over the pH range 2.9 to 7.8. However, decreasing pH led to decreased charge yields of CO2 reduction, due to increasing rates of the competing hydrogen evolution reaction. A reaction scheme was proposed to explain the observed relationship and a mathematical model was developed to quantify the dependence of the product ratios on pH and to predict the observed partial current densities of product formation at different pHs and electrode potentials. The reaction scheme was based on multiple protonation states of the intermediate in CO2 reduction; the higher the protonation state, the higher was the tendency of the intermediate to form CO. A generalised reaction mechanism for other electrode materials was also proposed

  8. A model for trace metal sorption processes at the calcite surface: Adsorption of Cd2+ and subsequent solid solution formation

    Science.gov (United States)

    Davis, J.A.; Fuller, C.C.; Cook, A.D.

    1987-01-01

    The rate of Cd2+ sorption by calcite was determined as a function of pH and Mg2+ in aqueous solutions saturated with respect to calcite but undersaturated with respect to CdCO3. The sorption is characterized by two reaction steps, with the first reaching completion within 24 hours. The second step proceeded at a slow and nearly constant rate for at least 7 days. The rate of calcite recrystallization was also studied, using a Ca2+ isotopic exchange technique. Both the recrystallization rate of calcite and the rate of slow Cd2+ sorption decrease with increasing pH or with increasing Mg2+. The recrystallization rate could be predicted from the number of moles of Ca present in the hydrated surface layer. A model is presented which is consistent with the rates of Cd2+ sorption and Ca2+ isotopic exchange. In the model, the first step in Cd2+ sorption involves a fast adsorption reaction that is followed by diffusion of Cd2+ into a surface layer of hydrated CaCO3 that overlies crystalline calcite. Desorption of Cd2+ from the hydrated layer is slow. The second step is solid solution formation in new crystalline material, which grows from the disordered mixture of Cd and Ca carbonate in the hydrated surface layer. Calculated distribution coefficients for solid solutions formed at the surface are slightly greater than the ratio of equilibrium constants for dissolution of calcite and CdCO3, which is the value that would be expected for an ideal solid solution in equilibrium with the aqueous solution. ?? 1987.

  9. Diagnostics and modeling of yttria-stabilized zirconia formation in solution-precursor plasma-spray process

    Science.gov (United States)

    Ozturk, Alper

    Thermal barrier coatings produced by solution-precursor plasma-spray (SPPS) process have been shown to offer superior thermal properties and durability. The microstructure of these coatings combines favorable properties of conventional air plasma spray (APS) and electron beam physical vapor deposition (EB-PVD) coatings by providing evenly spaced, through-thickness vertical cracks and uniformly distributed porosity resulting in good strain tolerance and low thermal conductivity. This experimental and computational study aims at clarifying some of the key aspects of this process through diagnostics of the actual process, modeling of vaporization and precipitation within droplets and through model experiments which utilize a combustion flame instead of a plasma jet. The work also includes characterization of the combustion flame and study of the possibility of coating formation utilizing combustion processes instead of plasmas. Plasma-extracted sample indicate presence of spherical sintered polycrystalline particles of 100 nm to 1 micron. Characterization of the precursor spray show that the mean droplet size is about 40 micron suggesting droplet disintegration in the process. Modeling of the heat and mass transfer around the droplets and solute precipitation predict formation of shell type structures and ceno-spheres supported by the experimental evidence of shell type structures in the single pass plasma experiments. Combustion flame experiments were found to produce sintered polycrystalline tetragonal yttria-stabilized zirconia particles similar to the plasma-extracted samples. The microstructural and compositional evolution of the ceramic particles was characterized as a function of downstream distance in the flame jet.

  10. Analysis of solutes in groundwaters from the Rustler Formation at and near the Waste Isolation Pilot Plant site

    International Nuclear Information System (INIS)

    Between 1976 and 1986, groundwater samples from more than 60 locations in the vicinity of the Waste Isolation Pilot Plant site were collected and analyzed for a variety of major, minor, and trace solutes. Most of the samples were from the Rustler Formation (the Culebra Dolomite, the Magenta Dolomite, or the zone at the contact between the Rustler and underlying Salado Formations) or the Dewey Lake Red Beds. The analytical data from the laboratories are presented here with accompanying discussions of sample collection methods, supporting field measurements, and laboratory analytical methods. A comparison of four data sets and a preliminary evaluation of the data for the major solutes (Cl-, SO4-2, Na, K, Ca, and Mg) shows that the data for samples analyzed by UNC/Bendix for SNL seem to be the most reliable, but that at some locations, samples representative of the native, unperturbed groundwater have not been collected. At other locations, the water chemistry has apparently changed between sampling episodes

  11. Solution NMR structure of CsgE: Structural insights into a chaperone and regulator protein important for functional amyloid formation.

    Science.gov (United States)

    Shu, Qin; Krezel, Andrzej M; Cusumano, Zachary T; Pinkner, Jerome S; Klein, Roger; Hultgren, Scott J; Frieden, Carl

    2016-06-28

    Curli, consisting primarily of major structural subunit CsgA, are functional amyloids produced on the surface of Escherichia coli, as well as many other enteric bacteria, and are involved in cell colonization and biofilm formation. CsgE is a periplasmic accessory protein that plays a crucial role in curli biogenesis. CsgE binds to both CsgA and the nonameric pore protein CsgG. The CsgG-CsgE complex is the curli secretion channel and is essential for the formation of the curli fibril in vivo. To better understand the role of CsgE in curli formation, we have determined the solution NMR structure of a double mutant of CsgE (W48A/F79A) that appears to be similar to the wild-type (WT) protein in overall structure and function but does not form mixed oligomers at NMR concentrations similar to the WT. The well-converged structure of this mutant has a core scaffold composed of a layer of two α-helices and a layer of three-stranded antiparallel β-sheet with flexible N and C termini. The structure of CsgE fits well into the cryoelectron microscopy density map of the CsgG-CsgE complex. We highlight a striking feature of the electrostatic potential surface in CsgE structure and present an assembly model of the CsgG-CsgE complex. We suggest a structural mechanism of the interaction between CsgE and CsgA. Understanding curli formation can provide the information necessary to develop treatments and therapeutic agents for biofilm-related infections and may benefit the prevention and treatment of amyloid diseases. CsgE could establish a paradigm for the regulation of amyloidogenesis because of its unique role in curli formation. PMID:27298344

  12. 3D model of small-scale density cavities in the auroral magnetosphere with field-aligned current

    Science.gov (United States)

    Bespalov, P. A.; Misonova, V. G.; Savina, O. N.

    2016-09-01

    We propose a 3D model of small-scale density cavities stimulated by an auroral field-aligned current and an oscillating field-aligned current of kinetic Alfvén waves. It is shown that when the field-aligned current increases so that the electron drift velocity exceeds a value of the order of the electron thermal velocity, the plasma becomes unstable to the formation of cavities with low density and strong electric field. The condition of instability is associated with the value of the background magnetic field. In the case of a relatively weak magnetic field (where the electron gyro-radius is greater than the ion acoustic wavelength), the current instability can lead to the formation of one-dimensional cavities along the magnetic field. In the case of a stronger magnetic field (where the ion acoustic wavelength is greater than the electron gyro-radius, but still is less than the ion gyro-radius), the instability can lead to the formation of 3D density cavities. In this case, the spatial scales of the cavity, both along and across the background magnetic field, can be comparable, and at the earlier stage of the cavity formation they are of the order of the ion acoustic wavelength. Rarefactions of the cavity density are accompanied by an increase in the electric field and are limited by the pressure of bipolar electric fields that occur within them. The estimates of typical density cavity characteristics and the results of numerical solutions agree with known experimental data: small-scale structures with a sufficiently strong electric field are observed in the auroral regions with strong field-aligned current.

  13. On Catastrophe and Cavitation for Spherical Cavity

    Institute of Scientific and Technical Information of China (English)

    MingJIN; KefuHUANG; 等

    1999-01-01

    This work deals with catastrophe of a spherical cavity and cavitation of a spherical cavity for Hooke material with 1/2 Poisson's ratio.A nonlinear problem.which is the Cauchy traction problem,is solved analytically.The governing equations are written on the deformed region or on the present configuration.And the conditions are described on moving boundary.A closed form solution is found.Furthermore,a bifurcation solution in closed form is given from the trivial homogeneous solution of a solid sphere.The results indicate that there is a tangent bifurcation on the displacement-load curve for a sphere with a cavity.On the tangent bifurcation point,the cavity grows up suddenly,which is a kind of catastrophe,And there is a pitchfork bifurcation on the displacement-load curve for a solid sphere.On the pitchfork bifurcation point.there is a cavitation in the solid sphere.

  14. Formation and decay of the peroxy radicals in the oxidation process of Glyoxal, Methylglyoxal and Hydroxyacetone in aqueous solution

    Science.gov (United States)

    Schaefer, Thomas; Weller, Christian; Herrmann, Hartmut

    2013-04-01

    Volatile organic compounds (VOCs) are emitted into the atmosphere in large amounts from biogenic and anthropogenic sources. For example, the semivolatile carbonyl compounds glyoxal and methylglyoxal will be produced in the oxidation process of isoprene, while hydroxyacetone can be formed by the combustion of biomass. Additionally, these semivolatile carbonyl compounds might be important for the formation of secondary organic aerosol (SOA) by partitioning between gas- and liquid phase of pre-existing particles. In the gas phase as well as in the aqueous phase (cloud droplets, fog, rain and deliquescent particles) these compounds can be further oxidized, e.g., by radicals (OH and NO3) leading to peroxy radical and then to substitued organics. There are still uncertainties concerning the oxidation pathways of glyoxal, after H-atom abstraction by, e.g., OH radicals, via alkyl radical to the peroxy radical under addition of molecular oxygen. One concept[1] claims that for dilute solutions ( 1 mM the formation of the peroxy radicals is a minor reaction pathway because of a lower rate constant of k = 1 × 106 M-1 s-1 estimated after Guzman et al., 2006[3]. The difference in the rate constants of the oxygen addition is of about three orders of magnitude and thus leads to different oxidation products and yields in the aqueous solution. Laboratory studies of glyoxal oxidation under varying oxygen concentrations have been performed in order to investigate the importance of the peroxy radical formation and alkyl radical recombination in more detail. The formation and the decay of the formed glyoxyl radicals and glyoxyl peroxy radicals were studied in low and high concentrated oxygen solutions using a laser photolysis long path absorption setup (LP-LPA). Additionally, the Tdependent decay of the peroxy radicals formed in the oxidation of methyglyoxal and hydroxyacetone was also studied using the same experiment. 1 Buxton, G. V., Malone, T. N. und Salmon, G. A., J. Chem. Soc

  15. Radiolytic formation of Ag clusters in aqueous polyvinyl alcohol solution and hydrogel matrix

    International Nuclear Information System (INIS)

    Ag+ ions, in aqueous polyvinyl alcohol (PVA) solution and in PVA hydrogel matrix have been gamma radiolytically reduced to produce Ag clusters. UV-visible absorption spectral characteristics of Ag clusters obtained under different gamma dose, Ag+ concentration, PVA concentration and crosslinking density of the gel used have been studied. The effect of Ag+ ions on the radiation crosslinking of the PVA chains, have also been investigated by viscosity measurements. The radiation-induced Ag+ ion reduction was followed by crosslinking of the PVA chains. PVA was found to be a very efficient stabilizer to prevent aggregation of Ag clusters. The clusters produced in the hydrogel matrix were expected to be smaller than the pore size (∼2-20 nm) of the gels used in the study. These Ag clusters were unable to reduce methyl viologen (MV2+) chloride and were stable in air

  16. By-products formation during degradation of isoproturon in aqueous solution. I: Ozonation.

    Science.gov (United States)

    Mascolo, G; Lopez, A; James, H; Fielding, M

    2001-05-01

    The degradation of the herbicide isoproturon during its ozonation in aqueous solution has been investigated with the aim of identifying intermediate as well as final by-products formed. At ambient temperature, phosphate-buffered (pH = 7) isoproturon aqueous solutions (10, 10(-1) and 10(-3) mg/l) were ozonated in a semi-batch reactor, under a continuous flow of ozonated air whose ozone concentration was 9 and 0.9 mg O3/lair for the highest and the two lower herbicide concentrations respectively. Measured steady-state ozone concentrations during the two sets of experiments (i.e. the highest and the lower isoproturon concentration) were 1.9 and 0.7 mg O3/l. Under all of the above conditions, isoproturon was always completely removed in a period ranging between 5 and 15 min, essentially by reacting with molecular ozone. High-performance liquid chromatography-mass spectrometry (HPLC-MS) analyses indicate that primary degradation by-products are formed either by introducing OH groups in the aromatic ring and/or in the side-chain substituents, or by breaking down the isopropyl alkyl chain. The results also show that these primary intermediates are successively degraded yielding low molecular weight compounds such as aldehydes, simple organic acids and alpha-oxo-acids, which have been identified by gas chromatography-electron capture detection (GC-ECD), ion chromatography (IC) and GC-MS, respectively. On the basis of the analytical results, a pathway for the degradation of isoproturon by ozone has been proposed. PMID:11329671

  17. Formation and Stability of the 4-Methoxyphenonium Ion in Aqueous Solution

    OpenAIRE

    Tsuji, Yutaka; Hara, Daisuke; Hagimoto, Rui; Richard, John P.

    2011-01-01

    The reaction of 2-methoxyphenylethyl tosylate (MeO-1-Ts) is first-order in [N3−]. A carbon-13 NMR analysis of the products of the reactions of MeO-1-[α–13C]Ts shows the formation of MeO-1-[β–13C]OH and MeO-1-[β–13C]N3 from the trapping of a symmetrical 4-methoxyphenonium ion reaction intermediate 2+. An analysis of the rate and product data provides a value of kaz/ks = 83 M−1 for partitioning of 2+ between addition of azide ion and solvent. These data set a limit for the lifetime of 2+ in aqu...

  18. Formation Equilibria of Ternary Metal Complexes with Citric Acid and Glutamine (Alanine) in Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    王进平; 牛春吉; 杨魁跃; 倪嘉缵

    2004-01-01

    The species and their formation constants in the ternary systems were obtained by the Scogs2 software from potentiometric titration data. The Comics software was used to calculate the distribution of species in the ternary systems. MLXH, MLXH2 and MLXH3 are the common species in these systems. The coordination behaviors of the rare earths are very similar and their stability is closely matched. The ternary rare earth complexes are more stable than the corresponding ternary complexes of calcium. The ternary zinc complex with glutamine as the secondary ligand is more stable than the corresponding complexes of rare earths, but the ternary complex with alanine as the secondary ligand shows an inverse trend. The distributions of species in the ternary systems vary with pH changing. A prediction can be made that exogenous rare earths can affect the species of Ca and Zn in human body.

  19. A study of the film formation kinetics on zinc in different acidic corrosion inhibitor solutions by quartz crystal microbalance

    International Nuclear Information System (INIS)

    Chromates conversion coatings provide very effective corrosion protection for many metals. However, the high toxicity of chromate leads to an increasing interest in using non-toxic alternatives such as molybdates, silicates, rare earth metal ions and etc. In this work, quartz crystal microbalance (QCM) was applied as an in-situ technique to follow the film formation process on zinc (plated on gold) in acidic solutions containing an inorganic inhibitor, i.e. potassium chromate, sodium silicate, sodium molybdate or cerium nitrate. Using an equation derived in this work, the interfacial mass change during the film formation process under different conditions was calculated, indicating three different film formation mechanisms. In the presence of K2CrO4 or Na2SiO3, the film growth follows a mix-parabolic law, showing a process controlled by both ion diffusion and surface reaction. The apparent kinetic equations are 0.4t = -17.4 + 20Δm f + (Δm f)2 and 0.1t = 19.0 + 8.4Δm f + 10(Δm f)2 respectively (t and Δm are in seconds and μg/cm2). In solutions containing Na2MoO4, a logarithmic law of Δm f = -24.7 + 6.6 ln t was observed. Changing the inhibitor to Ce(NO3)3, the film growth was found to obey an asymptote law that could be fit into the equation of Δm f = 55.1(1 - exp(-2.6 x 10-3 t))

  20. Formation conditions and nature of solid solutions in the Fe2O3 - V2O3 system

    International Nuclear Information System (INIS)

    The phase composition of Fe2O3 and V2O3 interaction products is unvestigated at different pressures of gas phase and temperature in the air conditions. It is established, that at low temperature up to 900 deg C, Fesub(2-2x)Vsub(2x)Osub(3) solid solution is forming in the individual ampules and above this temperature partial dissociation of Fe2O3 and appearance of Fesub(3-2x)Vsub(2x)Osub(4) solid solution on the base of magnetite with the spinel defect structure is observed. The formation of three phases with different structure: Fesub(2-2x)Vsub(2x)Osub(3), Fesub(3-2x)Vsub(2x)Osub(4) and V3O5 is observed simultaneously at annealing of samples in the general ampule at 1000 deg C. Thermal behaviour of the forming solid solutions in the air is studied

  1. The formation of magnetic carboxymethyl-dextrane-coated iron-oxide nanoparticles using precipitation from an aqueous solution

    International Nuclear Information System (INIS)

    The formation of spinel iron-oxide nanoparticles during the co-precipitation of Fe3+/Fe2+ ions from an aqueous solution in the presence of carboxymethyldextrane (CMD) was studied. To follow the formation of the nanoparticles, a mixture of the Fe ions, CMD and ammonia was heated to different temperatures, while the samples were taken, quenched in liquid nitrogen, freeze-dried and characterized using transmission electron microscopy (TEM), X-ray diffractometry (XRD) and magnetometry. The CMD plays a role in the reactions of the Fe ions' precipitation by partially immobilizing the Fe3+ ions into a complex. At room temperature, the amorphous material is precipitated. Then, above approximately 30 °C, the spinel nanoparticles form inside the amorphous matrix, and at approximately 40 °C the matrix decomposes into the suspension of carboxymethyl-dextrane-coated iron-oxide nanoparticles. The CMD bonded to the nanoparticles' surfaces hinders the mass transport and thus prevents their growth. - Highlights: • The carboxymethyl-dextrane coated iron-oxide nanoparticles were synthesized. • The carboxymethyl-dextrane significantly modifies formation of the spinel nanoparticles. • The spinel nanoparticles are formed inside the amorphous matrix. • At approximately 40 °C the matrix decomposes into the suspension of carboxymethyl-dextrane-coated iron-oxide nanoparticles

  2. The formation of magnetic carboxymethyl-dextrane-coated iron-oxide nanoparticles using precipitation from an aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Makovec, Darko [Department for Materials Synthesis, Jožef Stefan Institute, Jamova ulica 39, SI-1000 Ljubljana (Slovenia); Gyergyek, Sašo, E-mail: saso.gyergyek@ijs.si [Department for Materials Synthesis, Jožef Stefan Institute, Jamova ulica 39, SI-1000 Ljubljana (Slovenia); Primc, Darinka [Department for Materials Synthesis, Jožef Stefan Institute, Jamova ulica 39, SI-1000 Ljubljana (Slovenia); Plantan, Ivan [Lek Pharmaceuticals d.d., Mengeš (Slovenia)

    2015-03-01

    The formation of spinel iron-oxide nanoparticles during the co-precipitation of Fe{sup 3+}/Fe{sup 2+} ions from an aqueous solution in the presence of carboxymethyldextrane (CMD) was studied. To follow the formation of the nanoparticles, a mixture of the Fe ions, CMD and ammonia was heated to different temperatures, while the samples were taken, quenched in liquid nitrogen, freeze-dried and characterized using transmission electron microscopy (TEM), X-ray diffractometry (XRD) and magnetometry. The CMD plays a role in the reactions of the Fe ions' precipitation by partially immobilizing the Fe{sup 3+} ions into a complex. At room temperature, the amorphous material is precipitated. Then, above approximately 30 °C, the spinel nanoparticles form inside the amorphous matrix, and at approximately 40 °C the matrix decomposes into the suspension of carboxymethyl-dextrane-coated iron-oxide nanoparticles. The CMD bonded to the nanoparticles' surfaces hinders the mass transport and thus prevents their growth. - Highlights: • The carboxymethyl-dextrane coated iron-oxide nanoparticles were synthesized. • The carboxymethyl-dextrane significantly modifies formation of the spinel nanoparticles. • The spinel nanoparticles are formed inside the amorphous matrix. • At approximately 40 °C the matrix decomposes into the suspension of carboxymethyl-dextrane-coated iron-oxide nanoparticles.

  3. Effects of superoxide dismutase and formate ions on the radiolytic oxidation of dithiothreitol in aerated solutions

    International Nuclear Information System (INIS)

    In the radiolysis of dithiothreitol, G(H2O2), G(-SH), G(disulphide) and G(H2S) have been determined. The results show good material balance for sulphur. At low DTT and pH=5.8, G(H2O2) = 3.6 = Gsub(H2O2)sup(m) + 1/2 Gsub(H) + Gsub(e-sub(aq)) + Gsub(OH) both in the presence and absence of HCOONa. This shows that all the primary species are converted to O2 which dimerise to give H2O2. It is of interest to note that in DTT-HCOONa-O2 system at pH=7.0, G(H2O2) = 6.5 Gsub(H2O2)sup(m) + Gsub(H) + Gsub(e-sub(aq)) + Gsub(OH). This indicates that O2- produced from the primary species reacts with DTT to give H2O2. The results show that there is a small chain reaction at high DTT and increase in O2 does not affect the product yields. The enzyme superoxide dismutase (SOD), when added to DTT solution before irradiation does not change the product yields at low DTT, but the yields are lowered at high DTT. This is because O2- ions are converted to H2O2 by SOD before it initiates a chain reaction at high DTT. (author)

  4. Formation of reflective and conductive silver film on ABS surface via covalent grafting and solution spray

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Dexin; Zhang, Yan [School of Mechanical and Automotive Engineering, South China University of Technology, 381 Wushan, Guangzhou 510640 (China); Bessho, Takeshi [Higashifuji Technical Center, Toyota Motor Corporation, 1200 Mishuku, Susono, Shizuoka 410-1193 (Japan); Kudo, Takahiro; Sang, Jing; Hirahara, Hidetoshi; Mori, Kunio [Faculty of Engineering, Iwate University, 4-3-5 Ueda, Morioka 020-8551 (Japan); Kang, Zhixin, E-mail: zxkang@scut.edu.cn [School of Mechanical and Automotive Engineering, South China University of Technology, 381 Wushan, Guangzhou 510640 (China)

    2015-09-15

    Highlights: • A pure and homogenous silver film was deposited by spray-style plating technique. • The mechanism of covalent bonding between coating and substrate was studied. • The silver coating is highly reflective and conductive. • UV light was used to activate the ABS surface with triazine azide derivative. - Abstract: Conductive and reflective silver layers on acrylonitrile butadiene styrene (ABS) plastics have been prepared by photo grafting of triazine azides upon ultraviolet activation, self-assembling of triazine dithiols and silver electroless plating by solution spray based on silver mirror reaction. The as-prepared silver film exhibited excellent adhesion with ABS owing to covalent bonds between coating and substrate, and the detailed bonding mechanism have been investigated by X-ray photoelectron spectroscopy (XPS). X-ray diffraction (XRD) result revealed that silver film on ABS was pure and with a nanocrystalline structure. Atomic force microscope (AFM) analysis demonstrated that massive silver particles with sizes varying from 80 to 120 nm were deposited on ABS and formed a homogenous and smooth coating, resulting in highly reflective surface. Furthermore, silver maintained its unique conductivity even as film on ABS surface in term of four-point probe method.

  5. Formation of reflective and conductive silver film on ABS surface via covalent grafting and solution spray

    International Nuclear Information System (INIS)

    Highlights: • A pure and homogenous silver film was deposited by spray-style plating technique. • The mechanism of covalent bonding between coating and substrate was studied. • The silver coating is highly reflective and conductive. • UV light was used to activate the ABS surface with triazine azide derivative. - Abstract: Conductive and reflective silver layers on acrylonitrile butadiene styrene (ABS) plastics have been prepared by photo grafting of triazine azides upon ultraviolet activation, self-assembling of triazine dithiols and silver electroless plating by solution spray based on silver mirror reaction. The as-prepared silver film exhibited excellent adhesion with ABS owing to covalent bonds between coating and substrate, and the detailed bonding mechanism have been investigated by X-ray photoelectron spectroscopy (XPS). X-ray diffraction (XRD) result revealed that silver film on ABS was pure and with a nanocrystalline structure. Atomic force microscope (AFM) analysis demonstrated that massive silver particles with sizes varying from 80 to 120 nm were deposited on ABS and formed a homogenous and smooth coating, resulting in highly reflective surface. Furthermore, silver maintained its unique conductivity even as film on ABS surface in term of four-point probe method

  6. The Aggregation Behavior and Formation of Nanoparticles of Oleoylchitosan in Dilute Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    LI Yanyan; CHEN Xiguang; SUN Gangzheng; XING Ke

    2008-01-01

    Oleoylchitosans (O-chitosans) with different degrees of substitution (DS) were synthesized by reacting chitosan with oleoyl chloride. The chemical structures of the products were characterized by 1H NMR and FT-IR. These results suggested the for-mation of an amide linkage between the amino groups of chitosan and the carboxyl groups of oleic acid. The viscosity of O-chitosan sharply increased with the increase of concentration, whereas that of unmodified chitosan rose only slightly. This increase became larger as the DS increased. All of the O-chitosans could reduce surface tension slightly. The critical aggregation concentration (CAC) of O-chitosans with DS 5%, 11%, and 27% were 79.43 mgL-1, 31.6 mgL-1, and 10mgL-1, respectively. Nanoparticles were prepared using an O/W emulsification method. The mean diameters of the polymeric amphiphilic nanoparticles of O-chitosans with DS 5% and 11% were around 327.4 nm and 275.3 nm, respectively.

  7. Phase equilibrium conditions for simulated landfill gas hydrate formation in aqueous solutions of tetrabutylammonium nitrate

    International Nuclear Information System (INIS)

    Highlights: • Hydrate equilibrium conditions for the simulated landfill gas (LFG) were reported. • Thermodynamic effect of tetrabutylammonium nitrate changes with its mass fraction. • The phase boundary was determined by employing an isochoric pressure-search method. -- Abstract: Hydrate phase equilibrium conditions for the simulated landfill gas (LFG) of methane and carbon dioxide (50 mol% methane, 50 mol% carbon dioxide) were investigated with the pressure range of (1.90 to 13.83) MPa and temperature range of (280.0 to 288.3) K at (0.050, 0.170, 0.340, and 0.394) mass fraction (w) of tetrabutylammonium nitrate (TBANO3). The phase boundary between liquid–vapor–hydrate (L–V–H) phases and liquid–vapor (L–V) phases was determined by employing an isochoric pressure-search method. The phase equilibrium data measured showed that TBANO3 appeared a remarkable promotion effect at wTBANO3 = 0.394, corresponding to TBANO3 · 26H2O, but inhibition effect at wTBANO3 = (0.050, or 0.170) on the semiclathrate hydrate formation. In addition, the application of TBANO3 at 0.340 mass fraction, corresponding to TBANO3 · 32H2O, displayed promotion effect at lower pressures (below 6.38 MPa) and inhibition effect at higher pressures (above 6.38 MPa)

  8. Effect of initial pH and temperature of iron salt solutions on formation of magnetite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Gnanaprakash, G. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Mahadevan, S. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Jayakumar, T. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Kalyanasundaram, P. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Philip, John [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)]. E-mail: philip@igcar.gov.in; Raj, Baldev [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)

    2007-05-15

    We report the effect of initial pH and temperature of iron salt solutions on formation of magnetite (Fe{sub 3}O{sub 4}) nanoparticles during co-precipitation. We synthesized nanoparticles by keeping the initial pH at 0.7, 1.5, 3.0, 4.7, 5.7, 6.7 for two different temperatures of 30 and 60 deg. C. When the initial pH (prior to alkali addition) of the salt solution was below 5, the nanoparticles formed were 100% spinel iron oxide. Average size of the magnetite particles increases with initial pH until ferrihydrite is formed at a pH of 3 and the size remains the same till 4.7 pH. The percentage of goethite formed along with non-stoichiometric magnetite was 35 and 78%, respectively, when the initial pH of the solution was 5.7 and 6.7. As the reaction temperature was increased to 60 deg. C, maintaining a pH of 6.7, the amount of goethite increased from 78 to 100%. These results show that the initial pH and temperature of the ferrous and ferric salt solution before initiation of the precipitation reaction are critical parameters controlling the composition and size of nanoparticles formed. We characterize the samples using X-ray diffraction, transmission electron microscopy and vibrating sample magnetometer. The results of the present work provide the right conditions to synthesis pure magnetite nanoparticles, without goethite impurities, through co-precipitation technique for ferrofluid applications.

  9. Numerical Solution of the Radiative Transfer Equation: X-Ray Spectral Formation from Cylindrical Accretion onto a Magnetized Neutron Star

    Science.gov (United States)

    Fairnelli, R.; Ceccobello, C.; Romano, P.; Titarchuk, L.

    2011-01-01

    Predicting the emerging X-ray spectra in several astrophysical objects is of great importance, in particular when the observational data are compared with theoretical models. This requires developing numerical routines for the solution of the radiative transfer equation according to the expected physical conditions of the systems under study. Aims. We have developed an algorithm solving the radiative transfer equation in the Fokker-Planck approximation when both thermal and bulk Comptonization take place. The algorithm is essentially a relaxation method, where stable solutions are obtained when the system has reached its steady-state equilibrium. Methods. We obtained the solution of the radiative transfer equation in the two-dimensional domain defined by the photon energy E and optical depth of the system pi using finite-differences for the partial derivatives, and imposing specific boundary conditions for the solutions. We treated the case of cylindrical accretion onto a magnetized neutron star. Results. We considered a blackbody seed spectrum of photons with exponential distribution across the accretion column and for an accretion where the velocity reaches its maximum at the stellar surface and at the top of the accretion column, respectively. In both cases higher values of the electron temperature and of the optical depth pi produce flatter and harder spectra. Other parameters contributing to the spectral formation are the steepness of the vertical velocity profile, the albedo at the star surface, and the radius of the accretion column. The latter parameter modifies the emerging spectra in a specular way for the two assumed accretion profiles. Conclusions. The algorithm has been implemented in the XPEC package for X-ray fitting and is specifically dedicated to the physical framework of accretion at the polar cap of a neutron star with a high magnetic field (approx > 10(exp 12) G). This latter case is expected to be of typical accreting systems such as X

  10. Solid solution formation and microstructure of UO2 added with Nb and Ca

    International Nuclear Information System (INIS)

    Preparation of UO2 fuels added with Nb and Ca has been done by mixing UO2 with Nb2O5 and CaUO4 oxides respectively and heating them at 1390degC in stream of helium. Characterization has been then carried out with aid of X-ray diffraction analysis and metallography. The results can be summarized as follows. Nb could dissolve and form solid solution in UO2 with y up to 0.01, where y = Nb/(Ub+U) atomic ratio. The effect of Ca on the change of lattice parameter of the UO2 could be explained well using the simple ionic model, and according to this model, Ca occupies uranium sublattice of the UO2 (substitutional mechanism). Observation of the microstructure of the fuels showed that Nb created large grains and pores. The pores enlarged whether a liquid second phase was present or not. However, the grains did not enlarge and tended to be spherical when the liquid second phase was present. The structure of the liquid second phase could not be determined, but it had a melting point of 1328degC as confirmed by DTA. The evaluation also showed that Ca created small grains and pores. The difference in the grain and pore structure between (Nb,U)O2+x and (Ca,U)O2+x fuels was considered to be strongly due to the different lattice defect created by Nb and Ca, where Nb created a uranium vacancy which is considered to enhance the grain and pore growth and Ca created an oxygen vacancy which is considered to be less effective to enhance grain and pore growth. (author)

  11. Detection Of Multilayer Cavities By Employing RC-DTH Air Hammer System And Cavity Auto Scanning Laser System

    Science.gov (United States)

    Luo, Yongjiang; Li, Lijia; Peng, Jianming; Yin, Kun; Li, Peng; Gan, Xin; Zhao, Letao; Su, Wei

    2015-12-01

    The subterranean cavities are seriously threatened to construction and mining safety, and it's important to obtain the exact localization and dimensions of subterranean cavities for the planning of geotechnical and mining activities. Geophysical investigation is an alternative method for cavity detection, but it usually failed for the uncertainly solution of information and data obtained by Geophysical methods. Drilling is considered as the most accurate method for cavity detection. However, the conventional drilling methods can only be used for single cavity detection, and there is no effective solution for multilayer cavities detection have been reported. In this paper, a reverse circulation (RC) down-the-hole (DTH) air hammer system with a special structured drill bit is built and a cavity auto scanning laser system based on laser range finding technique was employed to confirm the localization and dimensions of the cavities. This RC-DTH air hammer system allows drilling through the upper cavities and putting the cavity auto scanning laser system into the cavity area through the central passage of the drill tools to protect the detection system from collapsing of borehole wall. The RC-DTH air hammer system was built, and field tests were conducted in Lanxian County Iron Ore District, which is located in Lv Liang city of Shan Xi province, the northwest of china. Field tests show that employing the RC-DTH air hammer system assisted by the cavity auto scanning laser system is an efficiency method to detect multilayer cavities.

  12. Modeling of Flow, Transport and Controlled Sedimentation Phenomena during Mixing of Salt Solutions in Complex Porous Formations

    Science.gov (United States)

    Skouras, Eugene D.; Jaho, Sofia; Pavlakou, Efstathia I.; Sygouni, Varvara; Petsi, Anastasia; Paraskeva, Christakis A.

    2015-04-01

    -dimensional pore network, the dependence of the mass balance in all major directions is taken into account, either as a three-dimensional network of pores with specific geometry (cylinders, sinusoidal cells), or as a homogeneous random medium (Darcy description). The distribution of the crystals along the porous medium was calculated in the case of selective crystallization on the walls, which is the predominant effect to date in the experiments. The crystals distribution was also examined in the case where crystallization was carried out in the bulk solution. Salts sedimentation experiments were simulated both in an unsaturated porous medium and in a medium saturated with an oil phase. A comparison of the simulation results with corresponding experimental results was performed in order to design improved selective sedimentation of salts systems in porous formations. ACKNOWLEDGMENTS This research was partially funded by the European Union (European Social Fund-ESF) and Greek National Funds through the Operational program "Education and Lifelong Learning" under the action Aristeia II (Code No 4420).

  13. Natural Frequency Analysis of Two Nonlinear Panels Coupled with a Cavity Using the Approximate Elliptic Integral Solution and the Method of Harmonic Residual Minimization

    Directory of Open Access Journals (Sweden)

    Y. Y. Lee

    2015-01-01

    Full Text Available The nonlinear structural acoustic problem considered in this study is the nonlinear natural frequency analysis of flexible double panels using the elliptic integral solution method. There are very limited studies for this nonlinear structural-acoustic problem, although many nonlinear plate or linear double panel problems have been tackled and solved. A multistructural/acoustic modal formulation is derived from two coupled partial differential equations which represent the large amplitude structural vibrations of the flexible panels and acoustic pressure induced within the air gap. One is the von Karman’s plate equation and the other is the homogeneous wave equation. The results obtained from the proposed method approach are verified with those from a numerical method. The effects of vibration amplitude, gap width, aspect ratio, the numbers of acoustic modes and harmonic terms, and so forth on the resonant frequencies of the in-phase and out of phase modes are examined.

  14. The mechanism of solute-enriched clusters formation in neutron-irradiated pressure vessel steels: The case of Fe-Cu model alloys

    Science.gov (United States)

    Subbotin, A. V.; Panyukov, S. V.

    2016-08-01

    Mechanism of solute-enriched clusters formation in neutron-irradiated pressure vessel steels is proposed and developed in case of Fe-Cu model alloys. The suggested solute-drag mechanism is analogous to the well-known zone-refining process. We show that the obtained results are in good agreement with available experimental data on the parameters of clusters enriched with the alloying elements. Our model explains why the formation of solute-enriched clusters does not happen in austenitic stainless steels with fcc lattice structure. It also allows to quantify the method of evaluation of neutron irradiation dose for the process of RPV steels hardening.

  15. The mechanism of solute-enriched clusters formation in neutron-irradiated pressure vessel steels: the case of Fe-Cu model alloys

    CERN Document Server

    Subbotina, A V

    2016-01-01

    Mechanism of solute-enriched clusters formation in neutron-irradiated pressure vessel steels is proposed and developed in case of Fe-Cu model alloys. We show that the obtained results are in a good agreement with available experimental data on the parameters of clusters enriched with the alloying elements. The suggested solute-drag mechanism is analogous to the well-known zone-refining process. Our model explains why the formation of solute-enriched clusters does not happen in austenitic stainless steels with fcc lattice structure. It also allows to quantify the method of evaluation of neutron irradiation dose for the process of RPV steels hardening.

  16. Hydrogen peroxide formation photoinduced by near-UV radiation in aqueous solutions of adenine derivatives at 77 K

    Science.gov (United States)

    Lozinova, T. A.; Lobanov, A. V.; Lander, A. V.

    2015-08-01

    An estimate of the content of free radicals in aqueous solutions of adenosine (Ado), adenosine-5'-diphosphate (ADP) and guanosine-5'-monophosphate (GMP) irradiated with near-UV radiation at 77 K is obtained by interpreting EPR spectra. It is established that in the presence of NaCl (0.1 M), the total number of peroxyl radicals O{2/-·} and HO{2/·} in samples of the studied compounds was 15-45% of the total quantity of produced free radicals and was affected by the conditions of exposure. The estimates are compared with the results from hydrogen peroxide (H2O2) determination in the same samples after thawing. Although the number of peroxyl radicals in the samples of adenine derivatives (A) and GMP are comparable, the formation of H2O2 is observed only in the case of A derivatives, but not in GMP. Possible reasons for these differences are discussed.

  17. Model simulation of solute leaching and its application for estimating the net rate of nitrate formation under field conditions

    Science.gov (United States)

    Otoma, Suehiro; Kuboi, Toru

    1985-12-01

    A model of the discrete type was built to describe unsteady infiltrations and redistributions of water and solutes in soil. The model was evaluated by comparing the measurements of the changes in chloride concentration in the field soil amended with sewage sludge with those obtained by simulation. The simulations showed that the amount of chloride adsorbed in the field was as small as 60% of that measured in the flask of the batch test, and that most of the chloride leached quickly through the upper zone of soil (0-20 cm) but stagnated in the lower zone (20-100 cm). The model was applied for estimating the daily net rate of nitrate formation. The estimation results indicated that the rate was accelerated remarkably by rainfall and abruptly slowed down soon after.

  18. Superconducting crab cavity

    International Nuclear Information System (INIS)

    Complete overlapping of the electron and positron bunches at colliding point can be attained by using the strong time-depending electromagnetic RF field in the superconducting crab cavity. Commissioning of the crab cavities started in February 2007 at KEKB. Effective head-on collision of electron and positron has been achieved successfully. After introduction of crab crossing and crab cavity, the structure and the fabrication of the KEKB superconducting crab cavity are discussed. (author)

  19. RF Cavity Design

    CERN Document Server

    Jensen, E

    2014-01-01

    After a short overview of a general approach to cavity design, we sketch the derivation of waveguide modes from plane waves and of cavity fields from waveguide modes. The characteristic parameters describing cavities and their performance are defined and explained. An equivalent circuit is introduced and extended to explain beam loading and higher order modes. Finally travelling- and standing-wave multi-gap cavities are introduced using the Brillouin diagram.

  20. Biodegradable chitin conduit tubulation combined with bone marrow mesenchymal stem cell transplantation for treatment of spinal cord injury by reducing glial scar and cavity formation

    Directory of Open Access Journals (Sweden)

    Feng Xue

    2015-01-01

    Full Text Available We examined the restorative effect of modified biodegradable chitin conduits in combination with bone marrow mesenchymal stem cell transplantation after right spinal cord hemisection injury. Immunohistochemical staining revealed that biological conduit sleeve bridging reduced glial scar formation and spinal muscular atrophy after spinal cord hemisection. Bone marrow mesenchymal stem cells survived and proliferated after transplantation in vivo, and differentiated into cells double-positive for S100 (Schwann cell marker and glial fibrillary acidic protein (glial cell marker at 8 weeks. Retrograde tracing showed that more nerve fibers had grown through the injured spinal cord at 14 weeks after combination therapy than either treatment alone. Our findings indicate that a biological conduit combined with bone marrow mesenchymal stem cell transplantation effectively prevented scar formation and provided a favorable local microenvironment for the proliferation, migration and differentiation of bone marrow mesenchymal stem cells in the spinal cord, thus promoting restoration following spinal cord hemisection injury.

  1. Biodegradable chitin conduit tubulation combined with bone marrow mesenchymal stem cell transplantation for treatment of spinal cord injury by reducing glial scar and cavity formation

    Institute of Scientific and Technical Information of China (English)

    Feng Xue; Er-jun Wu; Pei-xun Zhang; Li-ya A; Yu-hui Kou; Xiao-feng Yin; Na Han

    2015-01-01

    We examined the restorative effect of modiifed biodegradable chitin conduits in combination with bone marrow mesenchymal stem cell transplantation after right spinal cord hemisection injury. Immunohistochemical staining revealed that biological conduit sleeve bridging reduced glial scar formation and spinal muscular atrophy after spinal cord hemisection. Bone marrow mesenchymal stem cells survived and proliferated after transplantationin vivo, and differentiated into cells double-positive for S100 (Schwann cell marker) and glial ifbrillary acidic protein (glial cell marker) at 8 weeks. Retrograde tracing showed that more nerve ifbers had grown through the injured spinal cord at 14 weeks after combination therapy than either treatment alone. Our ifndings indicate that a biological conduit combined with bone marrow mesenchymal stem cell transplantation effectively prevented scar formation and provided a favorable local microenvi-ronment for the proliferation, migration and differentiation of bone marrow mesenchymal stem cells in the spinal cord, thus promoting restoration following spinal cord hemisection injury.

  2. Formation of High Aspect Ratio TiO2 Nano tube Arrays by Anodization of Ti Foil in Organic Solution

    International Nuclear Information System (INIS)

    Titanium oxide (TiO2) nano tubes were successfully formed by anodization of pure titanium foil in a standard two-electrode bath consisting of ethylene glycol solution containing 5 wt % NH4F. The pH of the solution was ∼7 and the anodization voltage was 60 V. It was observed that such anodization condition results in ordered arrays of TiO2 nano tubes with smooth surface and a very high aspect ratio. It was observed that a minimum of 1 wt % water addition was required to form well ordered TiO2 nano tubes with length of approximately 18.5 μm. As-anodized sample, the self-organized TiO2 nano tubes have amorphous structure and annealing at 500 degree Celsius of the nano tubes promote formation of anatase and rutile phase. Photo catalytic activity of well ordered TiO2 nano tubes with two different lengths was evaluated by measuring the degradation of methyl orange (MO). The elaboration of this observation is described in detail in this paper. (author)

  3. Electrochemical formation of GaAs honeycomb structure using a fluoride-containing (NH4)2SO4 solution

    International Nuclear Information System (INIS)

    GaAs substrates were anodized in the (NH4)2SO4 electrolyte with various fluoride concentrations. Scanning electron microscope (SEM) observation showed that highly regular honeycomb hollows were formed on the substrates anodized in the (NH4)2SO4 electrolyte with a small amount of HF concentration. The regularity of hollows decreased with the increase of HF concentration. The average diameter of hollows increased with increasing anodizing voltage. The regularity of hollow diameters increased with the increase of anodizing time, irrespective of the anodizing voltage. Cross-sectional SEM image showed that the average depth of regular hollows was about 5 nm. In addition to the peak in the region of fundamental adsorption of GaAs with the peak wavelength at about 870 nm, photoluminescence spectra of samples anodized in the (NH4)2SO4 electrolyte with HF concentration of 0.5 ml showed several peaks at about 610, 635, 670 and 720 nm. - Highlights: • We report on the electrochemical formation of GaAs honeycomb structure. • High regular hollows were formed by anodization in HF-containing (NH4)2SO4 solution. • A thin porous layer was formed by anodization in HF-containing (NH4)2SO4 solution. • This process is useful for preparing patterned substrate with a thin porous layer

  4. Biodegradable chitin conduit tubulation combined with bone marrow mesenchymal stem cell transplantation for treatment of spinal cord injury by reducing glial scar and cavity formation

    OpenAIRE

    Feng Xue; Er-jun Wu; Pei-xun Zhang; Li-ya A; Yu-hui Kou; Xiao-feng Yin; Na Han

    2015-01-01

    We examined the restorative effect of modified biodegradable chitin conduits in combination with bone marrow mesenchymal stem cell transplantation after right spinal cord hemisection injury. Immunohistochemical staining revealed that biological conduit sleeve bridging reduced glial scar formation and spinal muscular atrophy after spinal cord hemisection. Bone marrow mesenchymal stem cells survived and proliferated after transplantation in vivo, and differentiated into cells double-positive fo...

  5. Thermodynamics of mixed-ligand complex formation of zinc nitrilotriacetate with amino acids and dipeptides in solution

    International Nuclear Information System (INIS)

    Highlights: • Stable mixed ligand complexes of ZnNta with amino acids and dipeptides. • Histamine-like coordination mode of His in the complex ZnNtaHis. • Glycine-like coordination of Lys and Orn in the complexes ZnNtaL and ZnNtaHL • NH2, CO-coordination mode of GlyGly in the complex ZnNtaGG. • NH2, N− or NH2, N−, COO-coordination modes of GlyGly in the complex ZnNtaGGH−1. - Abstract: The isothermal calorimetry, pH-potentiometric titration and 1H and 13C NMR methods has been used to study the mixed-ligand complex formation in the systems Zn2+–Nta3––L− (L = His, Orn, Lys, GlyGly, AlaAla) in aqueous solution at 298.15 K and the ionic strength of I = 0.5 (KNO3). The thermodynamic parameters of formation of the mixed complexes have been determined. The relationship between the probable coordination modes of the complexone and amino acid or dipeptide molecules in the mixed-ligand complex and the thermodynamic parameters has been discussed

  6. Layered double hydroxide stability. 2. Formation of Cr(III)-containing layered double hydroxides directly from solution

    Science.gov (United States)

    Boclair, J. W.; Braterman, P. S.; Jiang, J.; Lou, S.; Yarberry, F.

    1999-01-01

    Solutions containing divalent metal [M(II) = Mg2+, Zn2+, Co2+, Ni2+, Mn2+] chlorides and CrCl3 6H2O were titrated with NaOH to yield, for M(II) = Zn, Co, and Ni, hydrotalcite-like layered double hydroxides (LDHs), [[M(II)]1-z[Cr(III)]z(OH)2][Cl]z yH2O, in a single step, without intermediate formation of chromium hydroxide. Analysis of the resultant titration curves yields solubility constants for these compounds. These are in the order Zn < Ni approximately Co, with a clear preference for formation of the phase with z = 1/3. With Mg2+ as chloride, titration gives a mixture of Cr(OH)3 and Mg(OH)2, but the metal sulfates give Mg2Cr(OH)6 1/2(SO4) by a two-step process. Titrimetric and spectroscopic evidence suggests short-range cation order in the one-step LDH systems.

  7. Thermodynamics of mixed-ligand complex formation of zinc nitrilotriacetate with amino acids and dipeptides in solution

    Energy Technology Data Exchange (ETDEWEB)

    Pyreu, Dmitrii, E-mail: pyreu@mail.ru [Department of Inorganic and Analytic Chemistry, Ivanovo State UniversityErmak 39, Ivanovo 153025 (Russian Federation); Gruzdev, Matvey; Kumeev, Roman [G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, Ivanovo (Russian Federation); Gridchin, Sergei [Ivanovo State University of Chemistry and Technology, Ivanovo (Russian Federation)

    2014-10-20

    Highlights: • Stable mixed ligand complexes of ZnNta with amino acids and dipeptides. • Histamine-like coordination mode of His in the complex ZnNtaHis. • Glycine-like coordination of Lys and Orn in the complexes ZnNtaL and ZnNtaHL • NH{sub 2}, CO-coordination mode of GlyGly in the complex ZnNtaGG. • NH{sub 2}, N{sup −} or NH2, N{sup −}, COO-coordination modes of GlyGly in the complex ZnNtaGGH{sub −1}. - Abstract: The isothermal calorimetry, pH-potentiometric titration and {sup 1}H and {sup 13}C NMR methods has been used to study the mixed-ligand complex formation in the systems Zn{sup 2+}–Nta{sup 3–}–L{sup −} (L = His, Orn, Lys, GlyGly, AlaAla) in aqueous solution at 298.15 K and the ionic strength of I = 0.5 (KNO{sub 3}). The thermodynamic parameters of formation of the mixed complexes have been determined. The relationship between the probable coordination modes of the complexone and amino acid or dipeptide molecules in the mixed-ligand complex and the thermodynamic parameters has been discussed.

  8. γ-radiolysis of poly(A) in aqueous solution: efficiency of strand break formation by primary water radicals

    International Nuclear Information System (INIS)

    γ-radiation-induced single-strand break formation (ssb) in polyadenylic acid (poly(A)) was determined in Ar and N2O-saturated solution in the presence of various concentrations of t-butanol. The efficiencies for strand breakage caused by solvated electrons, hydrogen atoms and OH radicals were found to be 0.25, 0.20 and 7.8%, respectively. The efficiency of OH radicals depends only slightly on pH (pH 5.0, 7.5 and 9.0) and is independent of the presence of salt (0.01 mol dm-3 NaClO4) and of irradiation temperature (200C and 700C). The efficiency of OH for ssb formation obtained in this work with poly(A) is much smaller than that of poly(dA), explained by different molecular conformations of the sugar moiety of poly(A) (3'-endo) and poly(dA) (2'-endo). With increasing t-butanol concentration more strand breaks are formed than expected from simple homogeneous competition kinetics of poly(A) and t-butanol for OH radicals, considered to be due to non-homogeneous reaction kinetics. Rate constants for the reaction of OH and H with poly(A) have been determined. (author)

  9. Study of solvent effects on complex formation of tungsten (VI) with ethylenediaminediacetic acid in aqueous solutions of propanol

    International Nuclear Information System (INIS)

    Spectrophotometric and potentiometric techniques were used to determine the formation constants of the species formed in the systems H+ + W(VI) + ethylenediaminediacetic acid and H+ + ethylenediaminediacetic acid in aqueous solutions of propanol at 25 deg C and constant ionic strength 0.1 mol dm-3 of sodium perchlorate. The composition of the complex was determined by the continuous variations method. It was shown that tungsten (VI) forms a mononuclear 1 : 1 complex with ethylenediaminediacetic acid of the type WO3L3- at -log[H+] = 5.8. The formation constants in various media were analyzed in terms of Kamlet and Taft's parameters. Solvents have been parameterized by scales of dipolarity/polarizability π*, hydrogen-bond donor strength α, and hydrogen-bond acceptor strength β. Linear dependence on these solvent parameters are used to correlate and predict a wide variety of solvent effects, as well as to provide an analysis of them. Linear relationships are observed when logKS is plotted versus π*. Finally, the results are discussed in terms of the effect of solvent on complexation

  10. Formation of alteration products during dissolution of vitrified ILW in a high-pH calcium-rich solution

    International Nuclear Information System (INIS)

    To simulate the possible disposition of a vitrified intermediate-level waste (ILW) in a cementitious environment within a geological disposal facility (GDF), the durability of a laboratory simulant ILW vitrified in a borosilicate glass in a saturated Ca(OH)2 solution (pH ∼12.5) was measured. Both a low surface area to volume (SA/V) ratio (∼10 m−1) Materials Characterisation Center test 1 (MCC-1) and a high SA/V ratio (∼10,000 m−1) product consistency test type B (PCT-B) were used at 50 °C for up to 170 days. The formation of alteration layers and products was followed. The surfaces of the monoliths were analysed using SEM/EDX and showed the formation of magnesium-rich precipitates and distinct calcium silicate hydrate (CSH) precipitates. Cross sections showed the development of a calcium-rich alteration layer, which was observed from 14 days. The altered layer was up to 5 μm thick after 170 days and showed accumulation of zirconium, iron and magnesium and to a lesser extent aluminium, along with calcium and silicon. Based on comparison of the rate data, it is suggested that the presence of this layer may offer some protection to the underlying glass. However, the high SA/V ratio experiments showed resumed alteration after 56 days, indicating that the altered layer may not be protective in the long term (under accelerated conditions). The formation of a magnesium-containing smectite clay (likely saponite) in addition to CSH(II), a jennite-like CSH phase, were identified in the high SA/V experiment by X-ray diffraction after 170 days. These results suggest that calcium and magnesium have important roles in both the long and shorter-term durability of vitrified wastes exposed to high pH

  11. Polynomial Chaos Expansion of random coefficients and the solution of stochastic partial differential equations in the Tensor Train format

    KAUST Repository

    Dolgov, S.

    2015-03-11

    We apply the Tensor Train (TT) decomposition to construct the tensor product Polynomial Chaos Expansion (PCE) of a random field, to solve the stochastic elliptic diffusion PDE with the stochastic Galerkin discretization, and to compute some quantities of interest (mean, variance, exceedance probabilities). We assume that the random diffusion coefficient is given as a smooth transformation of a Gaussian random field. In this case, the PCE is delivered by a complicated formula, which lacks an analytic TT representation. To construct its TT approximation numerically, we develop the new block TT cross algorithm, a method that computes the whole TT decomposition from a few evaluations of the PCE formula. The new method is conceptually similar to the adaptive cross approximation in the TT format, but is more efficient when several tensors must be stored in the same TT representation, which is the case for the PCE. Besides, we demonstrate how to assemble the stochastic Galerkin matrix and to compute the solution of the elliptic equation and its post-processing, staying in the TT format. We compare our technique with the traditional sparse polynomial chaos and the Monte Carlo approaches. In the tensor product polynomial chaos, the polynomial degree is bounded for each random variable independently. This provides higher accuracy than the sparse polynomial set or the Monte Carlo method, but the cardinality of the tensor product set grows exponentially with the number of random variables. However, when the PCE coefficients are implicitly approximated in the TT format, the computations with the full tensor product polynomial set become possible. In the numerical experiments, we confirm that the new methodology is competitive in a wide range of parameters, especially where high accuracy and high polynomial degrees are required.

  12. Polynomial Chaos Expansion of Random Coefficients and the Solution of Stochastic Partial Differential Equations in the Tensor Train Format

    KAUST Repository

    Dolgov, Sergey

    2015-11-03

    We apply the tensor train (TT) decomposition to construct the tensor product polynomial chaos expansion (PCE) of a random field, to solve the stochastic elliptic diffusion PDE with the stochastic Galerkin discretization, and to compute some quantities of interest (mean, variance, and exceedance probabilities). We assume that the random diffusion coefficient is given as a smooth transformation of a Gaussian random field. In this case, the PCE is delivered by a complicated formula, which lacks an analytic TT representation. To construct its TT approximation numerically, we develop the new block TT cross algorithm, a method that computes the whole TT decomposition from a few evaluations of the PCE formula. The new method is conceptually similar to the adaptive cross approximation in the TT format but is more efficient when several tensors must be stored in the same TT representation, which is the case for the PCE. In addition, we demonstrate how to assemble the stochastic Galerkin matrix and to compute the solution of the elliptic equation and its postprocessing, staying in the TT format. We compare our technique with the traditional sparse polynomial chaos and the Monte Carlo approaches. In the tensor product polynomial chaos, the polynomial degree is bounded for each random variable independently. This provides higher accuracy than the sparse polynomial set or the Monte Carlo method, but the cardinality of the tensor product set grows exponentially with the number of random variables. However, when the PCE coefficients are implicitly approximated in the TT format, the computations with the full tensor product polynomial set become possible. In the numerical experiments, we confirm that the new methodology is competitive in a wide range of parameters, especially where high accuracy and high polynomial degrees are required.

  13. Beam cavity interaction

    CERN Document Server

    Gamp, A

    2011-01-01

    We begin by giving a description of the rf generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, rf feedback, and feed-forward are described. Examples of digital rf phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  14. Cavity turnover and equilibrium cavity densities in a cottonwood bottomland

    Science.gov (United States)

    Sedgwick, James A.; Knopf, Fritz L.

    1992-01-01

    A fundamental factor regulating the numbers of secondary cavity nesting (SCN) birds is the number of extant cavities available for nesting. The number of available cavities may be thought of as being in an approximate equilibrium maintained by a very rough balance between recruitment and loss of cavities. Based on estimates of cavity recruitment and loss, we ascertained equilibrium cavity densities in a mature plains cottonwood (Populus sargentii) bottomland along the South Platte River in northeastern Colorado. Annual cavity recruitment, derived from density estimates of primary cavity nesting (PCN) birds and cavity excavation rates, was estimated to be 71-86 new cavities excavated/100 ha. Of 180 active cavities of 11 species of cavity-nesting birds found in 1985 and 1986, 83 were no longer usable by 1990, giving an average instantaneous rate of cavity loss of r = -0.230. From these values of cavity recruitment and cavity loss, equilibrium cavity density along the South Platte is 238-289 cavities/100 ha. This range of equilibrium cavity density is only slightly above the minimum of 205 cavities/100 ha required by SCN's and suggests that cavity availability may be limiting SCN densities along the South Platte River. We submit that snag management alone does not adequately address SCN habitat needs, and that cavity management, expressed in terms of cavity turnover and cavity densities, may be more useful.

  15. Formation of solid particles from aqueous solutions of palladium sulfate and of palladium sulfate-silver sulfate by gamma ray irradiation

    International Nuclear Information System (INIS)

    Aqueous solutions containing (a) palladium sulfate (b) palladium sulfate and silver sulfate, and (c) silver sulfate saturated with nitrogen were irradiated with cobalt 60 gamma radiations (dose rate, 2.35 and 11.2 kGy/h; temperature: 10 and 29-45degC). The pH's of the most solutions were 1.43 or 0.43. Formation of fine particles was studied from the decrease of optical absorption of the metal ions, and from mass measurement of solid precipitate. It was found that (1) palladium ion decreased with dose in the solutions (a) and (b) with appearance of continuum spectra from 200-700nm range due to solid particles, and (2) silver ion decreased with increasing dose in solution (b) while it did not decrease in solution (c), and (3) electric conductive precipitate was formed in solution (a) and solution (b), but no precipitate was found in solution (c) by the irradiation. The results indicate that (1) palladium ion was reduced to form metallic precipitate in any condition studied, but (b) silver ion was reduced only in the presence of palladium ion, and (3) bimetallic particles were formed in solution (b). The amounts of the precipitates recovered from the irradiated solutions were 57% for solution (a) and 97% for (b) of the amounts of ions reacted. (author)

  16. Solute based Lagrangian scheme in modeling the drying process of soft matter solutions.

    Science.gov (United States)

    Meng, Fanlong; Luo, Ling; Doi, Masao; Ouyang, Zhongcan

    2016-02-01

    We develop a new dynamical model to study the drying process of a droplet of soft matter solutions. The model includes the processes of solute diffusion, gel-layer formation and cavity creation. A new scheme is proposed to handle the diffusion dynamics taking place in such processes. In this scheme, the dynamics is described by the motion of material points taken on solute. It is convenient to apply this scheme to solve problems that involve moving boundaries and phase changes. As an example, we show results of a numerical calculation for a drying spherical droplet, and discuss how initial concentration and evaporation rate affect the structural evolution of the droplet. PMID:26920525

  17. Structural and silver/vanadium ratio effects on silver vanadium phosphorous oxide solution formation kinetics: impact on battery electrochemistry.

    Science.gov (United States)

    Bock, David C; Takeuchi, Kenneth J; Marschilok, Amy C; Takeuchi, Esther S

    2015-01-21

    The detailed understanding of non-faradaic parasitic reactions which diminish battery calendar life is essential to the development of effective batteries for use in long life applications. The dissolution of cathode materials including manganese, cobalt and vanadium oxides in battery systems has been identified as a battery failure mechanism, yet detailed dissolution studies including kinetic analysis are absent from the literature. The results presented here provide a framework for the quantitative and kinetic analyses of the dissolution of cathode materials which will aid the broader community in more fully understanding this battery failure mechanism. In this study, the dissolution of silver vanadium oxide, representing the primary battery powering implantable cardioverter defibrillators (ICD), is compared with the dissolution of silver vanadium phosphorous oxide (Ag(w)VxPyOz) materials which were targeted as alternatives to minimize solubility. This study contains the first kinetic analyses of silver and vanadium solution formation from Ag0.48VOPO4·1.9H2O and Ag2VP2O8, in a non-aqueous battery electrolyte. The kinetic results are compared with those of Ag2VO2PO4 and Ag2V4O11 to probe the relationships among crystal structure, stoichiometry, and solubility. For vanadium, significant dissolution was observed for Ag2V4O11 as well as for the phosphate oxide Ag0.49VOPO4·1.9H2O, which may involve structural water or the existence of multiple vanadium oxidation states. Notably, the materials from the SVPO family with the lowest vanadium solubility are Ag2VO2PO4 and Ag2VP2O8. The low concentrations and solution rates coupled with their electrochemical performance make these materials interesting alternatives to Ag2V4O11 for the ICD application. PMID:25478865

  18. Formation mechanism of solute clusters under neutron irradiation in ferritic model alloys and in a reactor pressure vessel steel: clusters of defects

    International Nuclear Information System (INIS)

    The embrittlement of reactor pressure vessel (RPV) under irradiation is partly due to the formation of point defects (PD) and solute clusters. The aim of this work was to gain more insight into the formation mechanisms of solute clusters in low copper ([Cu] = 0.1 wt%) FeCu and FeCuMnNi model alloys, in a copper free FeMnNi model alloy and in a low copper French RPV steel (16MND5). These materials were neutron-irradiated around 300 C in a test reactor. Solute clusters were characterized by tomographic atom probe whereas PD clusters were simulated with a rate theory numerical code calibrated under cascade damage conditions using transmission electron microscopy analysis. The confrontation between experiments and simulation reveals that a heterogeneous irradiation-induced solute precipitation/segregation probably occurs on PD clusters. (author)

  19. Effects of superoxide dismutase, dithiothreitol and formate ion on the inactivation of papain by hydroxyl and superoxide radicals in aerated solutions

    International Nuclear Information System (INIS)

    Losses in enzyme activity and sulphydryl content have been studied in aerated papain solutions containing formate, superoxide dismutase and dithiothreitol. Both formate and dithiothreitol converted .OH to .02-, whereas superoxide dismutase completely suppressed the inactivation by .02-. Using results from all systems, the fraction of .02- reactions with papain that caused inactivation of the enzyme was 0.33+-0.07. The results also showed that the fraction of .OH reactions, which cause inactivation of papain, is significantly higher in aerated than in oxygen-free solutions. (author)

  20. The Modelling of the Solids Solution Formation Process in Systems In2O3-HfO2 at Heating in Air

    Directory of Open Access Journals (Sweden)

    A.E. Soloviova

    2010-01-01

    Full Text Available The ionic radiuses for cations, namely, for indium, hafnium, anion, and anion vacancy on the Templiton and Dauben scale, were calculated based on the mathematical models of the solid solution formation in In2O3-HfO2 system. The phase transition in indium oxide, which is connected with disorder of anion vacancies in the C-type lattice, was revealed. The formation of solid solutions in In2O3-HfO2 system occurs based on the disordered C1-type phase of indium oxide. It was established that the limited solid solutions of the subtraction-substitution and subtraction-substitution-interstitial types are formed during the sample sintering at 1450 °C and 1600 °C in the air medium. The type of solid solution in In2O3-HfO2 system depends on the sizes of indium and hafnium cations. The solid-solution formation energies in the system were determined. It was found that the conductivity, concentration and charge carrier mobility depend on the solid solution type and not on the cation valence of dissolved impurity

  1. Electromagnetic SCRF Cavity Tuner

    Energy Technology Data Exchange (ETDEWEB)

    Kashikhin, V.; Borissov, E.; Foster, G.W.; Makulski, A.; Pischalnikov, Y.; Khabiboulline, T.; /Fermilab

    2009-05-01

    A novel prototype of SCRF cavity tuner is being designed and tested at Fermilab. This is a superconducting C-type iron dominated magnet having a 10 mm gap, axial symmetry, and a 1 Tesla field. Inside the gap is mounted a superconducting coil capable of moving {+-} 1 mm and producing a longitudinal force up to {+-} 1.5 kN. The static force applied to the RF cavity flanges provides a long-term cavity geometry tuning to a nominal frequency. The same coil powered by fast AC current pulse delivers mechanical perturbation for fast cavity tuning. This fast mechanical perturbation could be used to compensate a dynamic RF cavity detuning caused by cavity Lorentz forces and microphonics. A special configuration of magnet system was designed and tested.

  2. Superconducting cavity development

    International Nuclear Information System (INIS)

    Design and development work of the superconducting cavities for the Neutron Science Project is being continued since 1995. In the cavity design work, RF and structural analyses were carried out in order to determine the cavity shape and to obtain the RF and structural parameters. In the cavity development work, preparation of the test facility, fabrication and tests of the two single-cell prototype cavities of β=0.5 were performed. Good performance of the cavity was demonstrated in the test; obtained surface peak electric field of 44 MV/m is much higher than the design value of 16 MV/m. Resonant frequency shifts due to the vacuum load and the Lorentz force were also measured in the test. (author)

  3. A comparison of the product formation induced by ultrasonic waves and γ-rays in aqueous D-glucose solution

    International Nuclear Information System (INIS)

    The oxidation products obtained in aerated, aqueous α-D-glucose solutions after irradiation with ultrasonic waves and γ-rays were compared. Separation and identification were performed by gas chromatography/mass spectrometry and three methods for the derivatization of the products were used: 1) Trimethylsilylation pf the OH groups; 2) methoximation of the carbonyl groups followed by trimethylsilylation of the OH groups; 3) reduction of the carbonyl and carboxyl groups to alcohols by sodium borodeuteride, followed by trimetylsilylation of the OH groups. When using ultrasound and γ-irradiation identical products were observed: D-glucono-1,4-lactone, D-glucono-1,5-lactone, D-arabino-hexos-2-ulose, D-ribo-hexos-3-ulose, D-xylo-hexos-4-ulose, D-xylo-hexos-5-ulose, D-glucohexodialdose and arabino-1,4-lactone. From the results it was concluded that in ultrasound and γ-irradiation the same primary species and consecutive reactions are involved in product formation. (orig.)

  4. Repassivation behavior of 316L stainless steel in borate buffer solution: Kinetics analysis of anodic dissolution and film formation

    Science.gov (United States)

    Xu, Haisong; Sun, Dongbai; Yu, Hongying

    2015-12-01

    The repassivation behavior of metals or alloys after oxide film damage determines the development of local corrosion and corrosion resistance. In this work, the repassivation kinetics of 316L stainless steel (316L SS) are investigated in borate buffer solution (pH 9.1) by using the abrading electrode technique. The current densities flowing from bare 316L SS surface are measured by potentiostatic method and analyzed to characterize repassivation kinetics. The initial stages of current decay (t Avrami kinetics. Then the two independent components are analyzed individually. The film formation rate and the thickness of film are compared in different applied potential. It is shown that anodic dissolution dominates the repassivation for a short time during the early times, and a higher applied potential will promote the anodic dissolution of metal. The film growth rate increases slightly with increasing in potential. Correspondingly, increase in applied potential from 0 VSCE to 0.8 VSCE results in thicker monolayer, which covers the whole bare surface at the time of θ = 1. The electric field strengths through the thin passive film could reach 3.97 × 106 V cm-1.

  5. Catalytic condensation of formaldehyde in aqueous solution initiated by UV irradiation as putative "prebiological" route of the monosaccharides formation

    Science.gov (United States)

    Pestunova, O. P.; Simonov, A. N.; Matvienko, L. G.; Snytnikov, V. N.; Parmon, V. N.; Snytnikova, O. A.; Tsentalovich, Yu. P.

    The condensation of formaldehyde into higher monosaccharides in aqueous alkaline solutions catalyzed by several metal ions in particular Ca 2 and Mg 2 named as formose reaction is considered as a probable source of carbohydrates in prebiotic conditions Formaldehyde is detected in significant amounts in molecular clouds in space Undoubtedly it was an important gas component of circumsolar protoplanet disk Naturally formaldehyde could be dissolved in water of the Protoearth Calcium and magnesium that are capable of creating an alkaline medium are the abundant elements Thus the basic conditions for the formose reaction and for formation of monosaccharides in nature could be met However the formose reaction is autocatalytic since it can be initiated only in the presence of carbohydrates In spite of the fact that Russian chemist Butlerov discovered the formose reaction almost 150 years ago the reason of autocatalytic character of the process and the mechanism of initiation till now remained not quite clear In our work regular investigation of the mechanism of the formose reaction was carried out Influence of various initiators on reaction kinetics and composition of products was studied The composition of the formose reaction products in presence of different initiators is practically invariable under steady-state conditions and is caused by an aldol condensation of the lowest N 2 - and C 3 -carbohydrates The ability of the C 4 -C 6 sugars to initiate the formose reaction is revealed to correlate with the

  6. LEP copper accelerating cavities

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    These copper cavities were used to generate the radio frequency electric field that was used to accelerate electrons and positrons around the 27-km Large Electron-Positron (LEP) collider at CERN, which ran from 1989 to 2000. The copper cavities were gradually replaced from 1996 with new superconducting cavities allowing the collision energy to rise from 90 GeV to 200 GeV by mid-1999.

  7. Optically measuring interior cavities

    Science.gov (United States)

    Stone, Gary Franklin

    2009-11-03

    A method of measuring the three-dimensional volume or perimeter shape of an interior cavity includes the steps of collecting a first optical slice of data that represents a partial volume or perimeter shape of the interior cavity, collecting additional optical slices of data that represents a partial volume or perimeter shape of the interior cavity, and combining the first optical slice of data and the additional optical slices of data to calculate of the three-dimensional volume or perimeter shape of the interior cavity.

  8. Effects of modulated electron beams and cavities on reditrons

    Science.gov (United States)

    Kwan, T. J. T.; Davis, H. A.; Fulton, R. D.; Sherwood, E. G.

    The virtual cathode, when formed in a cavity, can generate microwaves at different cavity modes depending on the geometry of the cavity. We found that the formation and the oscillation frequency of the virtual cathode in a reditron can be significantly influenced by cavity designs. The length of a cavity can play a role in frequency and mode selection. Our simulations showed that TM sub 012 and TM sub 033 were excited for cavity lengths of 15.0 cm and 22.5 cm, respectively. In addition to the cavity effects on reditrons, we discovered that highly modulated electron beams can be produced in reditrons. Full modulation (100 percent) of the transmitted electron beam current has been confirmed in our simulations. We further showed that incorporation of an inverse diode configuration can achieve microwave production efficiency of 26 percent.

  9. Effects of modulated electron beams and cavities on reditrons

    Energy Technology Data Exchange (ETDEWEB)

    Kwan, T.J.T.; Davis, H.A.; Fulton, R.D.; Sherwood, E.G.

    1988-01-01

    The virtual cathode, when formed in a cavity, can generate microwaves at different cavity modes depending on the geometry of the cavity. We found that the formation and the oscillation frequency of the virtual cathode in a reditron can be significantly influenced by cavity designs. The length of a cavity can play a role in frequency and mode selection. Our simulations showed that TM/sub 012/ and TM/sub 033/ were excited for cavity lengths of 15.0 cm and 22.5 cm, respectively. In addition to the cavity effects on reditrons, we discovered that highly modulated electron beams can be produced in reditrons. Full modulation (100/percent/) of the transmitted electron beam current has been confirmed in our simulations. We further showed that incorporation of an inverse diode configuration can achieve microwave production efficiency of 26/percent/. 11 refs., 8 figs.

  10. Quantum yield of triplet formation of riboflavin in aqueous solution and of flavin mononucleotide bound to the LOV1 domain of Phot1 from Chlamydomonas reinhardtii

    International Nuclear Information System (INIS)

    The quantum yields of triplet formation, phiT, of riboflavin, and of flavin mononucleotide (FMN) bound to wild-type LOV1 domain (LOV1-WT) or bound to a mutated LOV1 domain (LOV1-C57S, cysteine 57 replaced by serine) of the photo-receptor Phot1 from the green alga Chlamydomonas reinhardtii are determined by picosecond laser double-pulse excitation and time-resolved fluorescence detection. The determined quantum yields of triplet formation are phiT=0.375±0.05 for riboflavinin in aqueous solution at pH=7, phiT=0.225±0.04 for FMN in LOV1-C57S in aqueous solution at pH=8, and phiT=0.255±0.04 for FMN in LOV1-WT in aqueous solution at pH = 8

  11. Metal-carbonate formation from ammonia solution by addition of metal salts - An effective method for CO2 capture from landfill gas (LFG)

    International Nuclear Information System (INIS)

    The absorption of CO2 from LFG in different weight concentration ammonia solution and metal salts (Zinc and Barium) is investigated in this study. Addition of metal salts results in useful metal carbonates when LFG is passed through the solution. Barium salts show a better potential of removing CO2 as compared to Zinc salts. Addition of Barium salts to ammonia solution results in a new absorbent as no study has been focused on it till date. Also metal salts are added to alkaline wastewater which not only decreases the pH of the wastewater but also useful metal carbonates are obtained from wastewater when LFG is passed through it. Different parameters like CO2 loading, reaction rate and change in pH are investigated. Formation of carbonates is proved by using SEM and XRD analysis. Raman spectroscopy was performed on the discarded liquid after removal of carbonates to understand the formation of bicarbonates, carbonates and carbamates. (author)

  12. SPS accelerating cavity

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    One of the SPS accelerating cavities (200 MHz, travelling wave structure). The power that is fed into the upstream end of the cavity is extracted at the downstream end and sent into a dump load. See 7603195 for more details, 7411032 for the travelling wave structure, and also 8011289, 8302397.

  13. SPS accelerating cavity

    CERN Multimedia

    1980-01-01

    One of the SPS acceleration cavities (200 MHz, travelling wave structure). On the ceiling one sees the coaxial transmission line which feeds the power from the amplifier, located in a surface building above, to the upstream end of the cavity. See 7603195 for more details, 7411032 for the travelling wave structure, and also 8104138, 8302397.

  14. Superconducting RF cavities

    CERN Document Server

    Bernard, Philippe

    1999-01-01

    It was 20 years ago when the research and development programme for LEP superconducting cavities was initiated. It lasted about 10 years. Today, my aim is not to tell you in great detail about the many innovations made thanks to our research, but I would like to point out some milestones in the development of superconducting cavities where Emilio's influence was particularly important.

  15. Ferrite loaded rf cavity

    International Nuclear Information System (INIS)

    The mechanism of a ferrite-loaded rf cavity is explained from the point of view of its operation. Then, an analysis of the automatic cavity-tuning system is presented using the transfer function; and a systematic analysis of a beam-feedback system using transfer functions is also presented. (author)

  16. Superconducting cavities for LEP

    CERN Multimedia

    1983-01-01

    Above: a 350 MHz superconducting accelerating cavity in niobium of the type envisaged for accelerating electrons and positrons in later phases of LEP. Below: a small 1 GHz cavity used for investigating the surface problems of superconducting niobium. Albert Insomby stays on the right. See Annual Report 1983 p. 51.

  17. Kinetics of the reactions of isoprene-derived hydroxynitrates: gas phase epoxide formation and solution phase hydrolysis

    Directory of Open Access Journals (Sweden)

    M. I. Jacobs

    2014-05-01

    Full Text Available Isoprene, the most abundant non-methane volatile organic compound (VOC emitted into the atmosphere, is known to undergo gas phase oxidation to form eight different hydroxynitrate isomers in "high NOx" environments. These hydroxynitrates are known to affect the global and regional formation of ozone and secondary organic aerosol (SOA, as well as affect the distribution of nitrogen. In the present study, we have synthesized three of the eight possible hydroxynitrates: 4-hydroxy-3-nitroxy isoprene (4,3-HNI and E/Z-1-hydroxy-4-nitroxy isoprene (1,4-HNI. Oxidation of the 4,3-HNI isomer by the OH radical was monitored using a flow tube chemical ionization mass spectrometer (FT-CIMS, and its OH rate constant was determined to be (3.64 ± 0.41 × 10−11 cm3 molecule−1 s−1. The products of 4,3-HNI oxidation were monitored, and a mechanism to explain the products was developed. An isoprene epoxide (IEPOX – a species important in SOA chemistry and thought to originate only from "low NOx" isoprene oxidation – was found as a minor, but significant product. Additionally, hydrolysis kinetics of the three synthesized isomers were monitored with NMR. The bulk, neutral solution hydrolysis rate constants for 4,3-HNI and the 1,4-HNI isomers were (1.59±0.03 × 10−5 s−1 and (6.76 ± 0.09 × 10−3 s−1, respectively. The hydrolysis reactions of each isomer were found to be general acid-catalyzed. The reaction pathways, product yields and atmospheric implications for both the gas phase and aerosol-phase reactions are discussed.

  18. Kinetics of the reactions of isoprene-derived hydroxynitrates: gas phase epoxide formation and solution phase hydrolysis

    Science.gov (United States)

    Jacobs, M. I.; Burke, W. J.; Elrod, M. J.

    2014-09-01

    Isoprene, the most abundant non-methane volatile organic compound (VOC) emitted into the atmosphere, is known to undergo gas phase oxidation to form eight different hydroxynitrate isomers in "high-NOx" environments. These hydroxynitrates are known to affect the global and regional formation of ozone and secondary organic aerosol (SOA), as well as affect the distribution of nitrogen. In the present study, we have synthesized three of the eight possible hydroxynitrates: 4-hydroxy-3-nitroxy isoprene (4,3-HNI) and E / Z-1-hydroxy-4-nitroxy isoprene (1,4-HNI). Oxidation of the 4,3-HNI isomer by the OH radical was monitored using a flow tube chemical ionization mass spectrometer (FT-CIMS), and its OH rate constant was determined to be (3.64 ± 0.41) × 10-11 cm3 molecule-1 s-1. The products of 4,3-HNI oxidation were monitored, and a mechanism to explain the products was developed. An isoprene epoxide (IEPOX) - a species important in SOA chemistry and thought to originate only from "low-NOx" isoprene oxidation - was found as a minor, but significant, product. Additionally, hydrolysis kinetics of the three synthesized isomers were monitored with nuclear magnetic resonance (NMR). The bulk, neutral solution hydrolysis rate constants for 4,3-HNI and the 1,4-HNI isomers were (1.59 ± 0.03) × 10-5 s-1 and (6.76 ± 0.09) × 10-3 s-1, respectively. The hydrolysis reactions of each isomer were found to be general acid-catalyzed. The reaction pathways, product yields and atmospheric implications for both the gas phase and aerosol phase reactions are discussed.

  19. In situ study of the solid-state formation of U1-xAmxO2±δ solid solution

    International Nuclear Information System (INIS)

    In order to reduce the nuclear waste inventory and radiotoxicity, U1-xAmxO2±δ materials are promising fuels for heterogeneous transmutation. In this context, they are generally fabricated from UO2+δ and AmO2-δ dioxide powders. In the subsequent solid solution, americium is assumed to be trivalent whereas uranium exhibits a mixed-valence (+IV/+V) state. However, no formation mechanisms were ever evidenced and, more particularly, it was not possible to know whether the reduction of Am(IV) to Am(III) occurs before the solid-solution formation, or only once it is established. In this study, we used high-temperature X-ray diffraction on a UO2±δ/AmO2-δ (15 mol %) mixture to observe in situ the formation of the U1-xAmxO2±δ solid solution. We show that UO2+δ is, at relatively low temperature (≤700 K), oxidized to U4O9-δ, which is likely to be caused by oxygen release from the simultaneous AmO2-δ reduction to cubic Am2O3±δ. Cubic Am2O3+δ then transforms to hexagonal Am2O3 at 1300 K Thus, the initial Am(IV) is fully reduced to Am(III) before the solid solution starts forming at 1740 K The UO2 fluorite phase vanishes after 4 h at 1970 K, indicating that the formation of the solid solution is completed, which proves that this solid solution is formed after the complete reduction of Am(IV) to Am(III). (authors)

  20. Passivated niobium cavities

    Science.gov (United States)

    Myneni, Ganapati Rao; Hjorvarsson, Bjorgvin; Ciovati, Gianluigi

    2006-12-19

    A niobium cavity exhibiting high quality factors at high gradients is provided by treating a niobium cavity through a process comprising: 1) removing surface oxides by plasma etching or a similar process; 2) removing hydrogen or other gases absorbed in the bulk niobium by high temperature treatment of the cavity under ultra high vacuum to achieve hydrogen outgassing; and 3) assuring the long term chemical stability of the niobium cavity by applying a passivating layer of a superconducting material having a superconducting transition temperature higher than niobium thereby reducing losses from electron (cooper pair) scattering in the near surface region of the interior of the niobium cavity. According to a preferred embodiment, the passivating layer comprises niobium nitride (NbN) applied by reactive sputtering.

  1. Tracing the origin of water and solute transfers in deep groundwater from Oxfordian, Dogger and Trias formations in the east of the Paris Basin - France

    International Nuclear Information System (INIS)

    In order to assess the feasibility for long lived radioactive wastes storage facilities in deep geological formation, solute transport processes must be investigated in the vicinity of the host formation. In France, the Oxfordian and Dogger limestone layers surrounding the Callovo-Oxfordian (COx) argillite in the east of the Paris Basin are investigated for this purpose. More than 60 samples of Oxfordian and Dogger formation groundwater and one sample of Triassic formation groundwater, located at the bottom section of the investigated sedimentary cover, were collected over a 250 km2 area, and were analysed for major ions, δ18O and δ2H of water, 87Sr/86Sr/, and δ34S and δ18O of dissolved sulphate. Oxfordian and Dogger formation water is from meteoric origin, and no direct water flow between Oxfordian, Dogger, nor Triassic formations was evidenced. Mineralization processes of the Dogger limestone groundwater were fully investigated. These processes correspond to a series of geochemical reactions including: calcite dissolution, incongruent dissolution of dolomite, ion addition from upward vertical diffusion through the sedimentary pile inducing cation exchange and further dissolution due to the increased ionic strength of the solutions. A PHREEQC model was developed to simulate inferred chemical processes. The model output is consistent with observed data. (authors)

  2. Lagrangian theory of structure formation in relativistic cosmology III: gravitoelectric perturbation and solution schemes at any order

    CERN Document Server

    Alles, Alexandre; Roumi, Fosca Al; Wiegand, Alexander

    2015-01-01

    The relativistic generalization of the Newtonian Lagrangian perturbation theory is investigated. In previous works, the first-order trace solutions that are generated by the spatially projected gravitoelectric part of the Weyl tensor were given together with extensions and applications for accessing the nonperturbative regime. We here furnish construction rules to obtain from Newtonian solutions the gravitoelectric class of relativistic solutions, for which we give the complete perturbation and solution schemes at any order of the perturbations. By construction, these schemes generalize the complete hierarchy of solutions of the Newtonian Lagrangian perturbation theory.

  3. SPS RF Accelerating Cavity

    CERN Multimedia

    1979-01-01

    This picture shows one of the 2 new cavities installed in 1978-1979. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also increased: to the first 2 MW plant a second 2 MW plant was added and by end 1979 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412016X, 7412017X, 7411048X

  4. SPS RF Cavity

    CERN Multimedia

    1975-01-01

    The picture shows one of the two initially installed cavities. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also gradually increased: by end 1980 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412017X, 7411048X, 7505074.

  5. The formation of supercooled brines, viscous liquids, and low-temperature perchlorate glasses in aqueous solutions relevant to Mars

    Science.gov (United States)

    Toner, J. D.; Catling, D. C.; Light, B.

    2014-05-01

    Salt solutions on Mars can stabilize liquid water at low temperatures by lowering the freezing point of water. The maximum equilibrium freezing-point depression possible, known as the eutectic temperature, suggests a lower temperature limit for liquid water on Mars; however, salt solutions can supercool below their eutectic before crystallization occurs. To investigate the magnitude of supercooling and its variation with salt composition and concentration, we performed slow cooling and warming experiments on pure salt solutions and saturated soil-solutions of MgSO4, MgCl2, NaCl, NaClO4, Mg(ClO4)2, and Ca(ClO4)2. By monitoring solution temperatures, we identified exothermic crystallization events and determined the composition of precipitated phases from the eutectic melting temperature. Our results indicate that supercooling is pervasive. In general, supercooling is greater in more concentrated solutions and with salts of Ca and Mg. Slowly cooled MgSO4, MgCl2, NaCl, and NaClO4 solutions investigated in this study typically supercool 5-15 °C below their eutectic temperature before crystallizing. The addition of soil to these salt solutions has a variable effect on supercooling. Relative to the pure salt solutions, supercooling decreases in MgSO4 soil-solutions, increases in MgCl2 soil-solutions, and is similar in NaCl and NaClO4 soil-solutions. Supercooling in MgSO4, MgCl2, NaCl, and NaClO4 solutions could marginally extend the duration of liquid water during relatively warm daytime temperatures in the martian summer. In contrast, we find that Mg(ClO4)2 and Ca(ClO4)2 solutions do not crystallize during slow cooling, but remain in a supercooled, liquid state until forming an amorphous glass near -120 °C. Even if soil is added to the solutions, a glass still forms during cooling. The large supercooling effect in Mg(ClO4)2 and Ca(ClO4)2 solutions has the potential to prevent water from freezing over diurnal and possibly annual cycles on Mars. Glasses are also

  6. Hydroforming of elliptical cavities

    Science.gov (United States)

    Singer, W.; Singer, X.; Jelezov, I.; Kneisel, P.

    2015-02-01

    Activities of the past several years in developing the technique of forming seamless (weldless) cavity cells by hydroforming are summarized. An overview of the technique developed at DESY for the fabrication of single cells and multicells of the TESLA cavity shape is given and the major rf results are presented. The forming is performed by expanding a seamless tube with internal water pressure while simultaneously swaging it axially. Prior to the expansion the tube is necked at the iris area and at the ends. Tube radii and axial displacements are computer controlled during the forming process in accordance with results of finite element method simulations for necking and expansion using the experimentally obtained strain-stress relationship of tube material. In cooperation with industry different methods of niobium seamless tube production have been explored. The most appropriate and successful method is a combination of spinning or deep drawing with flow forming. Several single-cell niobium cavities of the 1.3 GHz TESLA shape were produced by hydroforming. They reached accelerating gradients Eacc up to 35 MV /m after buffered chemical polishing (BCP) and up to 42 MV /m after electropolishing (EP). More recent work concentrated on fabrication and testing of multicell and nine-cell cavities. Several seamless two- and three-cell units were explored. Accelerating gradients Eacc of 30 - 35 MV /m were measured after BCP and Eacc up to 40 MV /m were reached after EP. Nine-cell niobium cavities combining three three-cell units were completed at the company E. Zanon. These cavities reached accelerating gradients of Eacc=30 - 35 MV /m . One cavity is successfully integrated in an XFEL cryomodule and is used in the operation of the FLASH linear accelerator at DESY. Additionally the fabrication of bimetallic single-cell and multicell NbCu cavities by hydroforming was successfully developed. Several NbCu clad single-cell and double-cell cavities of the TESLA shape have been

  7. Cavity-enhanced spectroscopies

    CERN Document Server

    van Zee, Roger

    2003-01-01

    ""Cavity-Enhanced Spectroscopy"" discusses the use of optical resonators and lasers to make sensitive spectroscopic measurements. This volume is written by the researcchers who pioneered these methods. The book reviews both the theory and practice behind these spectroscopic tools and discusses the scientific discoveries uncovered by these techniques. It begins with a chapter on the use of optical resonators for frequency stabilization of lasers, which is followed by in-depth chapters discussing cavity ring-down spectroscopy, frequency-modulated, cavity-enhanced spectroscopy, intracavity spectr

  8. SPS RF cavity

    CERN Multimedia

    1974-01-01

    The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. A power of up to 790 kW can be supplied to each giving a total accelerating voltage of about 8 MV. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities.

  9. Laser plasma interactions in fused silica cavities

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Xianzhong; Mao, Xianglei; Mao, Samuel S.; Yoo, Jong H.; Greif, Ralph; Russo, Richard E.

    2003-06-24

    The effect of laser energy on formation of a plasma inside a cavity was investigated. The temperature and electron number density of laser-induced plasmas in a fused silica cavity were determined using spectroscopic methods, and compared with laser ablation on a flat surface. Plasma temperature and electron number density during laser ablation in a cavity with aspect ratio of 4 increased faster with irradiance after the laser irradiance reached a threshold of 5 GW/cm{sup 2}. The threshold irradiance of particulate ejection was lower for laser ablation in a cavity compared with on a flat surface; the greater the cavity aspect ratio, the lower the threshold irradiance. The ionization of silicon becomes saturated and the crater depths were increased approximately by an order of magnitude after the irradiance reached the threshold. Phase explosion was discussed to explain the large change of both plasma characteristics and mass removal when irradiance increased beyond a threshold value. Self-focusing of the laser beam was discussed to be responsible for the decrease of the threshold in cavities.

  10. The standard molar enthalpies of formation of Pb2Fe2O5(s) and PbFe5O8.5(s) by acid solution calorimetry

    International Nuclear Information System (INIS)

    Highlights: ► Acid solution calorimetry studies to determine the enthalpy of formation of ternary compounds in (Pb + Fe + O) system. ► Standard molar enthalpy of formation of lead ferrites at 298 K. ► The standard enthalpy of formation of Pb2Fe2O5(s) is −(1324.2 ± 11.1) kJ mol−1. ► The standard enthalpy of formation of PbFe5O8.5(s) is −(2347.8 ± 10.7) kJ mol−1. - Abstract: The standard molar enthalpies of formation, ΔfHm0 (298.15 K) of Pb2Fe2O5(s) and PbFe5O8.5(s) have been determined using acid solution calorimetry. The enthalpies of solution of the compounds Pb2Fe2O5(s) and PbFe5O8.5(s), as well as those of mixtures of Fe2O3(s) and Pb3O4(s) in HCl (aq, 6 mol·dm−3) at 298.15 K were measured. Using these values, the standard enthalpies of formation (ΔfHm0) of Pb2Fe2O5(s) and PbFe5O8.5(s) were determined as −(1324.2 ± 11.1) kJ·mol−1 and −(2347.8 ± 10.7) kJ·mol−1, respectively.

  11. Fac-mer equilibria of coordinated iminodiacetate (ida2-) in ternary CuII(ida)(H-1B)- complex formation (B = imidazole, benzimidazole) in aqueous solution

    Indian Academy of Sciences (India)

    Susmita Bandyopadhyay; G N Mukherjee

    2003-08-01

    pH potentiometric and spectrophotometric investigations on the complex formation equilibria of CuII with iminodiacetate (ida2-) and heterocyclic N-bases, viz. imidazole and benzimidazole (B), in aqueous solution in binary and ternary systems using different molar ratios of the reactants indicated the formation of complexes of the types, Cu(ida), Cu(ida)(OH)-, (ida)Cu(OH)Cu(ida)-, Cu(B)2+, Cu(H-1B)+, Cu(ida)(H-1B)-, (ida)Cu(B)Cu(ida) and (ida)Cu(H-1B)Cu(ida)-. Formation constants of the complexes at 25 ± 1° at a fixed ionic strength, = 0.1 mol dm-3 (NaNO3) in aqueous solution were evaluated and the complex formation equilibria were elucidated with the aid of speciation curves. Departure of the experimental values of the reproportionation constants (log Cu) of ternary Cu(ida)(H-1B)- complexes from the statistically expected values, despite their formation in appreciable amounts at equilibrium, were assigned to fac(f)-mer(m) equilibria of the ida2- ligand coordinated to CuII, as the N-heterocyclic donors, (H-1B)-, coordinate trans- to the N-(ida2-) atom in the binary Cu(ida) complex to form the ternary Cu(ida) (H-1B)- complexes.

  12. Effect of Atomic Size and Valence Electron Concentration on the Formation of fcc or bcc Solid Solid Solutions in High Entropy Alloys

    OpenAIRE

    Coreño-Alonso, O.; Coreño-Alonso, J.

    2015-01-01

    The possibility of solid solution formation in high entropy alloys (HEAs) has been calculated for alloys with four to seven elements, using a rule previously reported. Thirty elements were included: transition elements of the fourth, fifth and sixth periods of the periodic table, and aluminum. A total of 2,799,486 systems were analyzed. The percentage of solid solutions that would be formed in HEAs decreases from 35.9% to 26.4%, as the number of elements increases from four to seven. The stru...

  13. Internalization of Calcium Oxalate Calculi Developed in Narrow Cavities

    Directory of Open Access Journals (Sweden)

    Fèlix Grases

    2014-03-01

    Full Text Available We describe the case of a patient with calcium oxalate monohydrate and calcium oxalate dihydrate calculi occluded in cavities. All those calculi were located inside narrow cavities covered with a thin epithelium that permits their visualization. Urinary biochemical analysis showed high calciuria, not hypercalciuria, hypocitraturia, and a ratio [calcium]/[citrate] >0.33. The existence of cavities of very low urodynamic efficacy was decisive in the formation of such calculi. It is important to emphasize that we observed a thin epithelium covering such cavities, demonstrating that this epithelium may be formed after the development of the calculi through a re-epithelialization process.

  14. SPS accelerating cavity

    CERN Multimedia

    1983-01-01

    See photo 8202397: View towards the downstream end of one of the SPS accelerating cavities (200 MHz, travelling wave structure). See 7603195 and 8011289 for more details, 7411032 for the travelling wave structure, and also 8104138.

  15. SPS accelerating cavity

    CERN Multimedia

    1983-01-01

    View towards the downstream end of one of the SPS accelerating cavities (200 MHz, travelling wave structure). See 7603195 and 8011289 for more details, 7411032 for the travelling wave structure, and also 8104138.

  16. accelerating cavity from LEP

    CERN Multimedia

    This is an accelerating cavity from LEP, with a layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities are now used in LEP to double the energy of the particle beams.

  17. Moving Detectors in Cavities

    CERN Document Server

    Obadia, N

    2007-01-01

    We consider two-level detectors, coupled to a quantum scalar field, moving inside cavities. We highlight some pathological resonant effects due to abrupt boundaries, and decide to describe the cavity by switching smoothly the interaction by a time-dependent gate-like function. Considering uniformly accelerated trajectories, we show that some specific choices of non-adiabatic switching have led to hazardous interpretations about the enhancement of the Unruh effect in cavities. More specifically, we show that the emission/absorption ratio takes arbitrary high values according to the emitted quanta properties and to the transients undergone at the entrance and the exit of the cavity, {\\it independently of the acceleration}. An explicit example is provided where we show that inertial and uniformly accelerated world-lines can even lead to the same ``pseudo-temperature''.

  18. SPS accelerating cavity

    CERN Multimedia

    1976-01-01

    The SPS started up with 2 accelerating cavities (each consisting of 5 tank sections) in LSS3. They have a 200 MHz travelling wave structure (see 7411032 and 7802190) and 750 kW of power is fed to each of the cavities from a 1 MW tetrode power amplifier, located in a surface building above, via a coaxial transmission line. Clemens Zettler, builder of the SPS RF system, is standing at the side of one of the cavities. In 1978 and 1979 another 2 cavities were added and entered service in 1980. These were part of the intensity improvement programme and served well for the new role of the SPS as proton-antiproton collider. See also 7411032, 8011289, 8104138, 8302397.

  19. Melatonin and Oral Cavity

    OpenAIRE

    Murat İnanç Cengiz; Seda Cengiz; Hom-Lay Wang

    2012-01-01

    While initially the oral cavity was considered to be mainly a source of various bacteria, their toxins and antigens, recent studies showed that it may also be a location of oxidative stress and periodontal inflammation. Accordingly, this paper focuses on the involvement of melatonin in oxidative stress diseases of oral cavity as well as on potential therapeutic implications of melatonin in dental disorders. Melatonin has immunomodulatory and antioxidant activities, stimulates the proliferatio...

  20. Oral cavity and leprosy

    OpenAIRE

    Shambulingappa Pallagatti; Soheyl Sheikh; Anupreet Kaur; Amit Aggarwal; Ravinder Singh2

    2012-01-01

    Although leprosy involves the oral cavity in up to 60% of the patients, examination of the oral cavity in leprosy clinics or oral health science clinics is often neglected. Oral involvement in leprosy can broadly be divided into non-specific and specific lesions. In this review, we discuss various oral manifestations in leprosy patients so as to increase the awareness about this aspect among dermatologists and dental surgeons.

  1. Hydroforming of Elliptical Cavities

    OpenAIRE

    W. Singer; Singer, X.; Jelezov, I.; Kneisel, P.

    2015-01-01

    Activities of the past several years in developing the technique of forming seamless (weldless) cavity cells by hydroforming are summarized. An overview of the technique developed at DESY for the fabrication of single cells and multicells of the TESLA cavity shape is given and the major rf results are presented. The forming is performed by expanding a seamless tube with internal water pressure while simultaneously swaging it axially. Prior to the expansion the tube is necked at the iris area ...

  2. Hybrid vertical cavity laser

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2010-01-01

    A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide.......A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide....

  3. Stability analysis for bad cavity lasers with inhomogeneously broadened gain

    CERN Document Server

    Kazakov, Georgy A

    2016-01-01

    Bad cavity lasers are experiencing renewed interest in the context of active optical frequency standards, due to their enhanced robustness against fluctuations of the laser cavity. The gain medium would consist of narrow-linewidth atoms, either trapped inside the cavity or intersecting the cavity mode dynamically. A finite velocity distribution, atomic interactions, or interactions of realistic multilevel atoms with external field leads to an inhomogeneous broadening of the atomic gain profile. This can bring the bad cavity laser to operate in unstable regimes characterized by complex temporal patterns of the field amplitude. We present a new and efficient method for the stability analysis of bad cavity lasers with inhomogeneously broadened gain. We apply this method to identify the steady-state solutions for the metrology-relevant case of spin-1/2 atoms interacting with an external magnetic field.

  4. Fluoride-containing nanoporous calcium-silicate MTA cements for endodontics and oral surgery: Early fluorapatite formation in a phosphate-containing solution

    OpenAIRE

    Gandolfi, M.G.; Taddei, P.; Siboni, F.; Modena, E.; Ginebra Molins, Maria Pau; Prati, Claudio

    2011-01-01

    Gandolfi MG, Taddei P, Siboni F, Modena E, Ginebra MP, Prati C. Fluoride-containing nanoporous calcium-silicate MTA cements for endodontics and oral surgery: early fluorapatite formation in a phosphate-containing solution. International Endodontic Journal, 44, 938–949, 2011. Aim To test the chemical–physical properties and apatite-forming ability of experimental fluoride-doped calcium silicate cements designed to create novel bioactive materials for use in endodontics ...

  5. LC-MS analysis in the e-beam and gamma radiolysis of metoprolol tartrate in aqueous solution: Structure elucidation and formation mechanism of radiolytic products

    Energy Technology Data Exchange (ETDEWEB)

    Slegers, Catherine [Unite d' Analyse Chimique et Physico-chimique des Medicaments, Universite Catholique de Louvain, CHAM 72.30, Avenue E. Mounier, 72, B-1200, Brussels (Belgium)]. E-mail: catherine.slegers@skynet.be; Maquille, Aubert [Unite d' Analyse Chimique et Physico-chimique des Medicaments, Universite Catholique de Louvain, CHAM 72.30, Avenue E. Mounier, 72, B-1200, Brussels (Belgium); Deridder, Veronique [Unite d' Analyse Chimique et Physico-chimique des Medicaments, Universite Catholique de Louvain, CHAM 72.30, Avenue E. Mounier, 72, B-1200, Brussels (Belgium); Sonveaux, Etienne [Unite de Chimie Pharmaceutique et de Radiopharmacie, Universite Catholique de Louvain, Brussels (Belgium); Habib Jiwan, Jean-Louis [Laboratoire de Spectrometrie de Masse, Universite Catholique de Louvain, Louvain-La-Neuve (Belgium); Tilquin, Bernard [Unite d' Analyse Chimique et Physico-chimique des Medicaments, Universite Catholique de Louvain, CHAM 72.30, Avenue E. Mounier, 72, B-1200, Brussels (Belgium)

    2006-09-15

    E-beam and gamma products from the radiolysis of aqueous solutions of ({+-})-metoprolol tartrate, saturated in nitrogen, are analyzed by HPLC with on-line mass and UV detectors. The structures of 10 radiolytic products common to e-beam and gamma irradiations are elucidated by comparing their fragmentation pattern to that of ({+-})-metoprolol. Two of the radiolytic products are also metabolites. Different routes for the formation of the radiolytic products are proposed.

  6. LC MS analysis in the e-beam and gamma radiolysis of metoprolol tartrate in aqueous solution: Structure elucidation and formation mechanism of radiolytic products

    Science.gov (United States)

    Slegers, Catherine; Maquille, Aubert; Deridder, Véronique; Sonveaux, Etienne; Habib Jiwan, Jean-Louis; Tilquin, Bernard

    2006-09-01

    E-beam and gamma products from the radiolysis of aqueous solutions of (±)-metoprolol tartrate, saturated in nitrogen, are analyzed by HPLC with on-line mass and UV detectors. The structures of 10 radiolytic products common to e-beam and gamma irradiations are elucidated by comparing their fragmentation pattern to that of (±)-metoprolol. Two of the radiolytic products are also metabolites. Different routes for the formation of the radiolytic products are proposed.

  7. LC-MS analysis in the e-beam and gamma radiolysis of metoprolol tartrate in aqueous solution: Structure elucidation and formation mechanism of radiolytic products

    International Nuclear Information System (INIS)

    E-beam and gamma products from the radiolysis of aqueous solutions of (±)-metoprolol tartrate, saturated in nitrogen, are analyzed by HPLC with on-line mass and UV detectors. The structures of 10 radiolytic products common to e-beam and gamma irradiations are elucidated by comparing their fragmentation pattern to that of (±)-metoprolol. Two of the radiolytic products are also metabolites. Different routes for the formation of the radiolytic products are proposed

  8. Effective mode volumes for leaky optical cavities

    DEFF Research Database (Denmark)

    Kristensen, Philip Trøst; Van Vlack, Cole; Hughes, Stephen

    2011-01-01

    definition of an effective mode volume is ambiguous and not applicable. Instead, we propose an alternative effective mode volume which can be easily evaluated based on the mode calculation methods typically applied in the literature and which is directly applicable to a much wider range of physical systems.......We show that for optical cavities with any finite dissipation, the term “cavity mode” should be understood as a solution to the Helmholtz equation with outgoing wave boundary conditions. This choice of boundary condition renders the problem non-Hermitian, and we demonstrate that the common...

  9. Cavity parameters identification for TESLA control system development

    International Nuclear Information System (INIS)

    The control system modeling for the TESLA - TeV-Energy Superconducting Linear Accelerator project has been developed for the efficient stabilization of the pulsed, accelerating EM field of the resonator. The cavity parameters identification is an essential task for the comprehensive control algorithm. The TESLA cavity simulator has been successfully implemented by applying very high speed FPGA - Field Programmable Gate Array technology. The electromechanical model of the cavity resonator includes the basic features - Lorentz force detuning and beam loading. The parameters identification bases on the electrical model of the cavity. The model is represented by the state space equation for the envelope of the cavity voltage driven by the current generator and the beam loading. For a given model structure, the over-determined matrix equation is created covering the long enough measurement range with the solution according to the least squares method. A low degree polynomial approximation is applied to estimate the time-varying cavity detuning during the pulse. The measurement channel distortion is considered, leading to the external cavity model seen by the controller. The comprehensive algorithm of the cavity parameters identification has been implemented in the Matlab system with different modes of the operation. Some experimental results have been presented for different cavity operational conditions. The following considerations have lead to the synthesis of the efficient algorithm for the cavity control system predicted for the potential FPGA technology implementation. (orig.)

  10. Solution set on the natural satellite formation orbits under first-order earth's non-spherical perturbation

    Institute of Scientific and Technical Information of China (English)

    Humei Wang; Wei Yang; Junfeng Li

    2005-01-01

    Using the reference orbital element approach, the precise governing equations for the relative motion of formation flight are formulated. A number of ideal formations with respect to an elliptic orbit can be designed based on the relative motion analysis from the equations. The features of the oscillating reference orbital elements are studied by using the perturbation theory. The changes in the relative orbit under perturbation are divided into three categories, termed scale enlargement, drift and distortion respectively. By properly choosing the initial mean orbital elements for the leader and follower satellites, the deviations from originally regular formation orbit caused by the perturbation can be suppressed. Thereby the natural formation is set up. It behaves either like non-disturbed or need little control to maintain.The presented reference orbital element approach highlights the kinematics properties of the relative motion and is convenient to incorporate the results of perturbation analysis on orbital elements. This method of formation design has advantages over other methods in seeking natural formation and in initializing formation.

  11. Inhibition of precipitation of carbonate apatite by trisodium citrate analysed in base of the formation of chemical complexes in growth solution

    Science.gov (United States)

    Prywer, Jolanta; Olszynski, Marcin; Mielniczek-Brzóska, Ewa

    2015-11-01

    Effect of trisodium citrate on the precipitation of carbonate apatite is studied. The experimental series are performed in the solution of artificial urine. The investigations are related to infectious urinary stones formation as carbonate apatite is one of the main components of this kind of stones. To mimic a real infection in urinary tract the aqueous ammonia solution was added to the solution of artificial urine. The spectrophotometric results demonstrate that trisodium citrate increases induction time with respect to carbonate apatite formation and decreases the efficiency of carbonate apatite precipitation. The inhibitory effect of trisodium citrate on the precipitation of carbonate apatite is explained in base of chemical speciation analysis. Such an analysis demonstrates that the inhibitory effect is mainly related with the fact that trisodium citrate binds Ca2+ ions and causes the formation of CaCit- and Ca10(PO4)6CO3 complexes. Trisodium citrate binds Ca2+ ions in the range of pH from 6 to 9.5 for which carbonate apatite is favored to be formed.

  12. Dusty plasma cavities: probe-induced and natural

    CERN Document Server

    Harris, B J; Hyde, T W

    2014-01-01

    A comprehensive exploration of regional dust evacuation in complex plasma crystals is presented. Voids created in 3D crystals on the International Space Station have provided a rich foundation for experiments, but cavities in dust crystals formed in ground-based experiments have not received as much attention. Inside a modified GEC RF cell, a powered vertical probe was used to clear the central area of a dust crystal, producing a cavity with high cylindrical symmetry. Cavities generated by three mechanisms are examined. First, repulsion of micrometer-sized particles by a negatively charged probe is investigated. A model of this effect developed for a DC plasma is modified and applied to explain new experimental data in RF plasma. Second, the formation of natural cavities is surveyed; a radial ion drag proposed to occur due to a curved sheath is considered in conjunction with thermophoresis and a flattened confinement potential above the center of the electrode. Finally, cavity formation unexpectedly occurs up...

  13. Phase Shift Interferometer and Growth Set Up to Step Pattern Formation During Growth From Solutions. Influence of the Oscillatory solution Flow on Stability

    Science.gov (United States)

    Chernov, Alex A.; Booth, N. A.; Vekilov, P. G.; Murray, B. T.; McFadden, G. B.

    2000-01-01

    We have assembled an experimental setup based on Michelson interferometry with the growing crystal surface as one of the reflective surfaces. The crystallization part of the device allows optical monitoring of a face of a crystal growing at temperature stable within 0.05 C in a flow of solution of controlled direction and speed. The reference arm of the interferometer contains a liquid crystal element that allows controlled shifts of the phase of the interferograms. We employ an image-processing algorithm, which combines five images with a pi/2 phase difference between each pair of images. The images are transferred to a computer by a camera capable of capturing 60 frames per second. The device allows data collection on surface morphology and kinetics during the face layers growth over a relatively large area (approximately 4 sq. mm) in situ and in real time during growth. The estimated depth resolution of the phase shifting interferometry is approximately 50 Angstroms. The data will be analyzed in order to reveal and monitor step bunching during the growth process. The crystal chosen as a model for study in this work is KH2PO4 (KDP). This optically non-linear material is widely used in frequency doubling applications. There have been a number of studies of the kinetics of KDP crystallization that can serve as a benchmark for our investigations. However, so far, systematic quantitative characteristics of step interaction and bunching are missing. We intend to present our first quantitative results on the onset, initial stages and development of instabilities in moving step trains on vicinal crystal surfaces at varying supersaturation, flow rate, and flow direction. Behavior of a vicinal face growing from solution flowing normal to the steps and periodically changing its direction in time was considered theoretically. It was found that this oscillating flow reduces both stabilization and destabilization effects resulted from the unidirectional solution flow directed

  14. Reversible formation of CdSe nanoparticles in aqueous solutions by high-energy electron beam irradiation

    International Nuclear Information System (INIS)

    An unusual reversible effect was observed in the synthesis of CdSe nanoparticles in the aqueous tertiary butanol solutions containing equimolar Cd[NH3]4SO4 and Na2SeSO3 by the high-energy electron beam irradiation. These nanoparticles were found to be unstable in the aqueous solutions and decomposed upon exposure to air/oxygen. However, they were stable in the de-aerated aqueous solutions and both aerated and de-aerated organic solvents. The decomposed aqueous solutions again produced these nanoparticles upon irradiation with the electron beam. On the contrary, the cadmium selenide nanoparticles synthesized with the cobalt-60 γ-irradiation, were stable under ambient conditions and did not exhibit any reversible behavior. This was attributed to the vast differences in the dose rates involved in the two types of synthetic processes, leading to a remarkable variation in the crystal structure and size of the nanoparticles.

  15. An integrated study of uranyl mineral dissolution processes. Etch pit formation, effects of cations in solution, and secondary precipitation

    International Nuclear Information System (INIS)

    Understanding the mechanism(s) of uranium-mineral dissolution is crucial for predictive modeling of U mobility in the subsurface. In order to understand how pH and type of cation in solution may affect dissolution, experiments were performed on mainly single crystals of curite, Pb2+3(H2O)2[(UO2)4O4(OH)3]2, becquerelite, Ca(H2O)8[(UO2)6O4(OH)6], billietite, Ba(H2O)7[(UO2)6O4(OH)6], fourmarierite Pb2+1-x(H2O)4[(UO2)4O3-2x(OH)4+2x] (x= 0.00-0.50), uranophane, Ca(H2O)5[(UO2)(SiO3OH)]2, zippeite, K3(H2O)3[(UO2)4(SO4)2O3(OH)], and Na-substituted metaschoepite, Na1-x[(UO2)4O2-x(OH)5+x] (H2O)n. Solutions included: deionized water; aqueous HCl solutions at pH 3.5 and 2; 0.5 mol L-1 Pb(II)-, Ba-, Sr-, Ca-, Mg-, HCl solutions at pH 2; 1.0 mol L-1 Na- and K-HCl solutions at pH 2; and a 0.1 mol L-1 Na2CO3 solution at pH 10.5. Uranyl mineral basal surface microtopography, micromorphology, and composition were examined prior to, and after dissolution experiments on micrometer scale specimens using atomic force microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. Evolution of etch pit depth at different pH values and experimental durations can be explained using a stepwave dissolution model. Effects of the cation in solution on etch pit symmetry and morphology can be explained using an adsorption model involving specific surface sites. Surface precipitation of the following phases was observed: (a) a highly-hydrated uranyl-hydroxy-hydrate in ultrapure water (on all minerals), (b) a Na-uranyl-hydroxy-hydrate in Na2CO3 solution of pH 10.5 (on uranyl-hydroxy-hydrate minerals), (c) a Na-uranyl-carbonate on zippeite, (d) Ba- and Pb-uranyl-hydroxy-hydrates in Ba-HCl and Pb-HCl solutions of pH 2 (on uranophane), (e) a (SiOx(OH)4-2x) phase in solutions of pH 2 (uranophane), and (f) sulfate-bearing phases in solutions of pH 2 and 3.5 (on zippeite).

  16. Oxygen vacancy formation in CeO2 and Ce(1-x)Zr(x)O2 solid solutions: electron localization, electrostatic potential and structural relaxation.

    Science.gov (United States)

    Wang, Hai-Feng; Li, Hui-Ying; Gong, Xue-Qing; Guo, Yang-Long; Lu, Guan-Zhong; Hu, P

    2012-12-28

    Ceria (CeO(2)) and ceria-based composite materials, especially Ce(1-x)Zr(x)O(2) solid solutions, possess a wide range of applications in many important catalytic processes, such as three-way catalysts, owing to their excellent oxygen storage capacity (OSC) through the oxygen vacancy formation and refilling. Much of this activity has focused on the understanding of the electronic and structural properties of defective CeO(2) with and without doping, and comprehending the determining factor for oxygen vacancy formation and the rule to tune the formation energy by doping has constituted a central issue in material chemistry related to ceria. However, the calculation on electronic structures and the corresponding relaxation patterns in defective CeO(2-x) oxides remains at present a challenge in the DFT framework. A pragmatic approach based on density functional theory with the inclusion of on-site Coulomb correction, i.e. the so-called DFT + U technique, has been extensively applied in the majority of recent theoretical investigations. Firstly, we review briefly the latest electronic structure calculations of defective CeO(2)(111), focusing on the phenomenon of multiple configurations of the localized 4f electrons, as well as the discussions of its formation mechanism and the catalytic role in activating the O(2) molecule. Secondly, aiming at shedding light on the doping effect on tuning the oxygen vacancy formation in ceria-based solid solutions, we summarize the recent theoretical results of Ce(1-x)Zr(x)O(2) solid solutions in terms of the effect of dopant concentrations and crystal phases. A general model on O vacancy formation is also discussed; it consists of electrostatic and structural relaxation terms, and the vital role of the later is emphasized. Particularly, we discuss the crucial role of the localized structural relaxation patterns in determining the superb oxygen storage capacity in kappa-phase Ce(1-x)Zr(1-x)O(2). Thirdly, we briefly discuss some

  17. Formation of globules and aggregates of DNA chains in DNA/polyethylene glycol/monovalent salt aqueous solutions

    OpenAIRE

    Kawakita, H.; Uneyama, T.; Kojima, M; Morishima, K.; Masubuchi, Y.; Watanabe, H.(Max-Planck-Institut für Kernphysik, 69117, Heidelberg, Germany)

    2009-01-01

    It has been known that giant DNA shows structural transitions in aqueous solutions under the existence of counterions and other polymers. However, the mechanism of these transitions has not been fully understood. In this study, we directly observed structures of probed (dye-labeled), dilute DNA chains in unprobed DNA/polyethylene glycol (PEG)/monovalent salt (NaCl) aqueous solutions with fluorescent microscopy to examine this mechanism. Specifically, we varied the PEG molecular weight and sal...

  18. Impact of forming, welding, and electropolishing on pitting and the surface finish of SRF cavity niobium

    International Nuclear Information System (INIS)

    A broad range of coupon electropolishing experiments are described to ascertain the mechanism(s) by which large defects are formed near superconducting radiofrequency (SRF) cavity welds. Cold-worked vs. annealed metal, the presence of a weld, and several variations of electropolishing (EP) parameters were considered. Pitting is strongly promoted by cold work and agitation of the EP solution. Welding also promotes pitting, but less so compared with the other factors above. Temperature increase during EP did not strongly affect glossiness or pitting, but the reduced viscosity made the electrolyte more susceptible to agitation. The experiments suggest that several factors that are rather benign alone are combined by the cavity forming, welding, and processing sequence to promote the formation of defects such as pits. Process changes to mitigate these risks are discussed.

  19. Impact of forming, welding, and electropolishing on pitting and the surface finish of SRF cavity niobium

    Energy Technology Data Exchange (ETDEWEB)

    Cooley, L.D.; Burk, D.; Cooper, C.; Dhanaraj, N.; Foley, M.; Ford, D.; Gould, K.; Hicks, D.; Novitski, R.; Romanenko, A.; Schuessler, R.; /Fermilab

    2010-07-01

    A broad range of coupon electropolishing experiments are described to ascertain the mechanism(s) by which large defects are formed near superconducting radiofrequency (SRF) cavity welds. Cold-worked vs. annealed metal, the presence of a weld, and several variations of electropolishing (EP) parameters were considered. Pitting is strongly promoted by cold work and agitation of the EP solution. Welding also promotes pitting, but less so compared with the other factors above. Temperature increase during EP did not strongly affect glossiness or pitting, but the reduced viscosity made the electrolyte more susceptible to agitation. The experiments suggest that several factors that are rather benign alone are combined by the cavity forming, welding, and processing sequence to promote the formation of defects such as pits. Process changes to mitigate these risks are discussed.

  20. A Numerical Method for Cavity Identification in Beams on an Elastic Foundation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An analytical solution for the natural frequencies of a beam containing a cavity on an elastic foundation is presented. Based on the analytical solution, a numerical method for identifying cavities in the foundation is developed. The position and size of the cavities are identified by minimizing an objective function, which is formulated according to the difference between the computed and measured natural frequencies of the system. The conjugate gradient algorithm is adopted for minimizing the objective function. Some numerical examples are presented to demonstrate the applicability of the presented cavity determination method. The results show that the presented method can be used to identify the cavity position and size conveniently and efficiently.

  1. Experimental Results for Direct Electron Irradiation of a Uranyl Sulfate Solution: Bubble Formation and Thermal Hydraulics Studies

    International Nuclear Information System (INIS)

    In support of the development of accelerator-driven production of fission product Mo-99 as proposed by SHINE Medical Technologies, a 35 MeV electron linac was used to irradiate depleted-uranium (DU) uranyl sulfate dissolved in pH 1 sulfuric acid at average power densities of 6 kW, 12 kW, and 15 kW. During these irradiations, gas bubbles were generated in the solution due to the radiolytic decomposition of water molecules in the solution. Multiple video cameras were used to record the behavior of bubble generation and transport in the solution. Seven six-channel thermocouples were used to record temperature gradients in the solution from self-heating. Measurements of hydrogen and oxygen concentrations in a helium sweep gas were recorded by a gas chromatograph to estimate production rates during irradiation. These data are being used to validate a computational fluid dynamics (CFD) model of the experiment that includes multiphase flow and a custom bubble injection model for the solution region.

  2. Experimental Results for Direct Electron Irradiation of a Uranyl Sulfate Solution: Bubble Formation and Thermal Hydraulics Studies

    Energy Technology Data Exchange (ETDEWEB)

    Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Makarashvili, Vakhtang [Argonne National Lab. (ANL), Argonne, IL (United States); Heltemes, Thad [Argonne National Lab. (ANL), Argonne, IL (United States); Sun, Zaijing [Argonne National Lab. (ANL), Argonne, IL (United States); Wardle, Kent E. [Argonne National Lab. (ANL), Argonne, IL (United States); Bailey, James [Argonne National Lab. (ANL), Argonne, IL (United States); Stepinski, Dominique [Argonne National Lab. (ANL), Argonne, IL (United States); Jerden, James [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-01-30

    In support of the development of accelerator-driven production of fission product Mo-99 as proposed by SHINE Medical Technologies, a 35 MeV electron linac was used to irradiate depleted-uranium (DU) uranyl sulfate dissolved in pH 1 sulfuric acid at average power densities of 6 kW, 12 kW, and 15 kW. During these irradiations, gas bubbles were generated in the solution due to the radiolytic decomposition of water molecules in the solution. Multiple video cameras were used to record the behavior of bubble generation and transport in the solution. Seven six-channel thermocouples were used to record temperature gradients in the solution from self-heating. Measurements of hydrogen and oxygen concentrations in a helium sweep gas were recorded by a gas chromatograph to estimate production rates during irradiation. These data are being used to validate a computational fluid dynamics (CFD) model of the experiment that includes multiphase flow and a custom bubble injection model for the solution region.

  3. A possible solution to the [alpha/Fe]-sigma problem in early type galaxies within a hierarchical galaxy formation model

    CERN Document Server

    Calura, Francesco

    2011-01-01

    The most massive elliptical galaxies apparently formed the fastest, because the ratio of alpha elements (such as oxygen) to iron is the smallest. In fact, iron is mainly produced from type Ia supernovae on a timescale of ~ 0.1-1 billion years, while the alpha elements come from massive stars on timescales of a few tens of million years (Matteucci 1994). Reproducing such a alpha/Fe correlation has long been a severe problem for cosmological theories of galaxy formation, which envisage massive galaxies to assemble gradually from smaller progenitors, and to be characterized by a star formation history too much extended towards late cosmic times. While it has recently become clear that feedback from Active Galactic Nuclei (AGN) activity play a role in the late quenching of star formation (e.g. Cattaneo et al. 2009), and that early star formation history in the galaxy progenitors affect the alpha/Fe ratio (Calura & Menci 2009), major mergers alone cannot enhance the star formation in the high-redshift progenit...

  4. Numerical solution of the radiative transfer equation: X-ray spectral formation from cylindrical accretion onto a magnetized neutron star

    CERN Document Server

    Farinelli, R; Romano, P; Titarchuk, L

    2011-01-01

    Predicting the emerging X-ray spectra in several astrophysical objects is of great importance, in particular when the observational data are compared with theoretical models. To this aim, we have developed an algorithm solving the radiative transfer equation in the Fokker-Planck approximation when both thermal and bulk Comptonization take place. The algorithm is essentially a relaxation method, where stable solutions are obtained when the system has reached its steady-state equilibrium. We obtained the solution of the radiative transfer equation in the two-dimensional domain defined by the photon energy E and optical depth of the system tau using finite-differences for the partial derivatives, and imposing specific boundary conditions for the solutions. We treated the case of cylindrical accretion onto a magnetized neutron star. We considered a blackbody seed spectrum of photons with exponential distribution across the accretion column and for an accretion where the velocity reaches its maximum at the stellar...

  5. Prominence mass supply and the cavity

    International Nuclear Information System (INIS)

    A prevalent but untested paradigm is often used to describe the prominence-cavity system: the cavity is under-dense because it is evacuated by supplying mass to the condensed prominence. The thermal non-equilibrium (TNE) model of prominence formation offers a theoretical framework to predict the thermodynamic evolution of the prominence and the surrounding corona. We examine the evidence for a prominence-cavity connection by comparing the TNE model with diagnostics of dynamic extreme ultraviolet (EUV) emission surrounding the prominence, specifically prominence horns. Horns are correlated extensions of prominence plasma and coronal plasma which appear to connect the prominence and cavity. The TNE model predicts that large-scale brightenings will occur in the Solar Dynamics Observatory Atmospheric Imaging Assembly 171 Å bandpass near the prominence that are associated with the cooling phase of condensation formation. In our simulations, variations in the magnitude of footpoint heating lead to variations in the duration, spatial scale, and temporal offset between emission enhancements in the other EUV bandpasses. While these predictions match well a subset of the horn observations, the range of variations in the observed structures is not captured by the model. We discuss the implications of our one-dimensional loop simulations for the three-dimensional time-averaged equilibrium in the prominence and the cavity. Evidence suggests that horns are likely caused by condensing prominence plasma, but the larger question of whether this process produces a density-depleted cavity requires a more tightly constrained model of heating and better knowledge of the associated magnetic structure.

  6. Formation of mixed U(IV)·U(VI) hydroxide sol in aqueous solutions with pH 1.5-4

    International Nuclear Information System (INIS)

    Adding of Cs2UCl6 weighted sample to 1.5-4 pH solutions saturated with the argon and containing 1x10-4-0.1 mole/l of UO2(ClO4)2 results in the U(V) production, so that U(IV), U(V) and U(VI) are in the equilibrium. However, upon the completion of the induction period one observes the formation of the black color colloid particles consisting of U(VI) containing U(IV) polymer. As pH increases from 1.5 up to 4 or as the temperature rises the induction period is reduced. Under the anaerobic conditions the colloidal solution is stable within the time period longer than one month. The 8000 rot/min (5500g) centrifuging enables to separate the colloid particles from the liquid phase. The colloid vanishes slowly in the argon saturated mineral acids or in K2CO3 solution, while the precipitates of the separate freshly prepared U(IV) and U(VI) hydroxides dissolve rapidly. The UV light short-time irradiation of UO2(ClO4)2 solution saturated with the argon and containing (2.5 pH) ethanol results in the production of U(V) undergoing disproportionation subsequently, and U(IV) forms with U(VI) a black colloid similar to that observed when U(IV) solution is mixed with U(VI) one

  7. Structural effects and microheterogeneity in concentrated solutions and their role in the formation of chloride complexes of cadmium

    International Nuclear Information System (INIS)

    Processes of cadmium chloride complexes formation in the systems CdAn2-Nacl-H2O, where An = Cl-, ClO4-, NO3-, were studied by the methods of polythermal solubility, 1H NMR and Raman spectroscopy. It was ascertained that in the range of pre-eutectic concentrations of cadmium salts all possible forms of cadmium chloride complexes are formed, while in post-eutectic range the process of the complex formation is of structurally enforced character. Mechanisms of chloride complexes formation in perchlorate and nitrate systems are suggested. The conclusion is made that in contrast to chloride system the nitrate and perchlorate systems in the presence of NaCl are characterized by structural microheterogeneity

  8. The optimization of CdSe nanoparticles synthesis in the apoferritin cavity

    International Nuclear Information System (INIS)

    Cadmium selenide nanoparticles (CdSe NPs) were synthesized in the cavity of the cage-shaped protein, apoferritin, by designing a slow chemical reaction, which employs tetraamminecadmium ion and selenourea. The ammonia water concentration and solution pH were optimized and the suppression of the formation of selenium oxide was also studied by deoxydation of the reaction solution. At the concentration of 5 mM ammonia water and at pH 9.5, with N2 gas bubbling, the core formation ratio (CFR) of CdSe NPs reached 75% and yield of protein ratio (YPR) was as high as 98%. N2 gas bubbling of reaction solution was found to be critical for the high CFR and high YPR of the CdSe NPs synthesis in apoferritin cavity. Using this optimized conditions, high quality CdSe NPs were obtained by the bio-template, apoferritin protein method. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  9. The optimization of CdSe nanoparticles synthesis in the apoferritin cavity

    Energy Technology Data Exchange (ETDEWEB)

    Iwahori, Kenji [CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012 (Japan); Morioka, Takuya [Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192 (Japan); Yamashita, Ichiro [CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012 (Japan); Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192 (Japan); Advanced Technology Research Laboratories, Matsushita Electronic Industrial Company, Ltd., 3-4 Hikaridai, Seika, Kyoto, 619-0237 (Japan)

    2006-09-15

    Cadmium selenide nanoparticles (CdSe NPs) were synthesized in the cavity of the cage-shaped protein, apoferritin, by designing a slow chemical reaction, which employs tetraamminecadmium ion and selenourea. The ammonia water concentration and solution pH were optimized and the suppression of the formation of selenium oxide was also studied by deoxydation of the reaction solution. At the concentration of 5 mM ammonia water and at pH 9.5, with N{sub 2} gas bubbling, the core formation ratio (CFR) of CdSe NPs reached 75% and yield of protein ratio (YPR) was as high as 98%. N{sub 2} gas bubbling of reaction solution was found to be critical for the high CFR and high YPR of the CdSe NPs synthesis in apoferritin cavity. Using this optimized conditions, high quality CdSe NPs were obtained by the bio-template, apoferritin protein method. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  10. A spherical cavity model for quadrupolar dielectrics.

    Science.gov (United States)

    Dimitrova, Iglika M; Slavchov, Radomir I; Ivanov, Tzanko; Mosbach, Sebastian

    2016-03-21

    The dielectric properties of a fluid composed of molecules possessing both dipole and quadrupole moments are studied based on a model of the Onsager type (molecule in the centre of a spherical cavity). The dielectric permittivity ε and the macroscopic quadrupole polarizability αQ of the fluid are related to the basic molecular characteristics (molecular dipole, polarizability, quadrupole, quadrupolarizability). The effect of αQ is to increase the reaction field, to bring forth reaction field gradient, to decrease the cavity field, and to bring forth cavity field gradient. The effects from the quadrupole terms are significant in the case of small cavity size in a non-polar liquid. The quadrupoles in the medium are shown to have a small but measurable effect on the dielectric permittivity of several liquids (Ar, Kr, Xe, CH4, N2, CO2, CS2, C6H6, H2O, CH3OH). The theory is used to calculate the macroscopic quadrupolarizabilities of these fluids as functions of pressure and temperature. The cavity radii are also determined for these liquids, and it is shown that they are functions of density only. This extension of Onsager's theory will be important for non-polar solutions (fuel, crude oil, liquid CO2), especially at increased pressures. PMID:27004882

  11. Model studies for the direct effect of high-energy irradiation on DNA. Mechanism of strand break formation induced by laser photoionization of poly U in aqueous solution

    International Nuclear Information System (INIS)

    Laser flash photolysis of polyuridylic acid (poly U) in anoxic aqeuous solutions leads to biphotonic photoionization of the uracil moiety followed by the formation of single strand breaks (ssb). The rate constant for ssb formation (1.0 s-1, obtained from the slow component of conductivity increase at 230C and pH 6.8) increases with decreasing pH to 235 s-1 at pH 3.5. The activation energy (pre-exponential factor) was measured to be 66 kJ mol-1 (5 x 1011 s-1) at pH 6.8. Addition of dithiothreitol (DTT) or glutathione (GSH) prevents ssb formation by reacting with a poly U intermediate (rate constant = 1.2 x 106 and 0.16 x 106 dm3 mol-1 s-1, respectively). Since with OH radicals as initiators very similar data have been obtained for the kinetics of ssb formation and for the reaction with DTT, it is concluded that photoionization of the uracil moiety in poly U leads eventually to the same chemical pathway for ssb formation as that induced by OH radicals. Furthermore, it is proposed that protection by DTT and GSH occurs via H donation to the C-4' radicals of the sugar moiety of DNA and to the C-4' and the C-2' radicals of poly U. (author)

  12. Investigating and Modeling the Thermo-dynamic Impact of Electrolyte Solutions of Sodium Chloride and Sodium Sulfate on Prevention of the Formation of Methane Hydrate

    Directory of Open Access Journals (Sweden)

    M. Manteghian

    2013-07-01

    Full Text Available Devising methods to prevent hydrate formation is of the important issues in natural gas industry. Since a great deal of money is annually spent on using hydrate inhibitors, identification of new inhibitors with higher degrees of efficacy is economically justifiable. Bearing in mind the significant role of hydrate inhibitors in prevention of natural gas pipelines’ getting blocked, the present study attempts to investigate two compounds of NaCl and Na2SO4 as inhibitors of hydrate methane’s formation so as to respond to “what is the inhibitive thermo-dynamic impact of electrolyte compounds of NaCl and Na2SO4 on the formation of methane hydrate?” To do so, this study not only measures the equilibrium temperature and pressure of methane hydrate formation in the presence of electrolyte solutions of NaCl and Na2SO4 and compares the results obtained with the state lacking such inhibitors, but it also assesses the regression and mathematical modeling are utilized within a basic virtual environment in order to propose a model for prediction of thermo-dynamic equilibrium temperature and pressure of methane hydrate formation.

  13. Metasurface external cavity laser

    Science.gov (United States)

    Xu, Luyao; Curwen, Christopher A.; Hon, Philip W. C.; Chen, Qi-Sheng; Itoh, Tatsuo; Williams, Benjamin S.

    2015-11-01

    A vertical-external-cavity surface-emitting-laser is demonstrated in the terahertz range, which is based upon an amplifying metasurface reflector composed of a sub-wavelength array of antenna-coupled quantum-cascade sub-cavities. Lasing is possible when the metasurface reflector is placed into a low-loss external cavity such that the external cavity—not the sub-cavities—determines the beam properties. A near-Gaussian beam of 4.3° × 5.1° divergence is observed and an output power level >5 mW is achieved. The polarized response of the metasurface allows the use of a wire-grid polarizer as an output coupler that is continuously tunable.

  14. Metasurface external cavity laser

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Luyao, E-mail: luyaoxu.ee@ucla.edu; Curwen, Christopher A.; Williams, Benjamin S. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); California NanoSystems Institute, University of California, Los Angeles, California 90095 (United States); Hon, Philip W. C.; Itoh, Tatsuo [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Chen, Qi-Sheng [Northrop Grumman Aerospace Systems, Redondo Beach, California 90278 (United States)

    2015-11-30

    A vertical-external-cavity surface-emitting-laser is demonstrated in the terahertz range, which is based upon an amplifying metasurface reflector composed of a sub-wavelength array of antenna-coupled quantum-cascade sub-cavities. Lasing is possible when the metasurface reflector is placed into a low-loss external cavity such that the external cavity—not the sub-cavities—determines the beam properties. A near-Gaussian beam of 4.3° × 5.1° divergence is observed and an output power level >5 mW is achieved. The polarized response of the metasurface allows the use of a wire-grid polarizer as an output coupler that is continuously tunable.

  15. Estimation of Abraham solvation equation coefficients for hydrogen bond formation from Abraham solvation parameters for solute acidity and basicity.

    Science.gov (United States)

    van Noort, Paul

    2013-01-01

    Abraham solvation equations find widespread use in environmental chemistry and pharmaco-chemistry. The coefficients in these equations, which are solvent (system) descriptors, are usually determined by fitting experimental data. To simplify the determination of these coefficients in Abraham solvation equations, this study derives equations, based on Abraham solvation parameters for hydrogen acidity and basicity of the solvents involved, to estimate the value of the coefficients for hydrogen bond formation. These equations were applied to calculate Abraham solvation parameters for hydrogen acidity and basicity for polyoxymethylene, polyacrylate, sodium dodecylsulfate, some ionic liquids, alkanoyl phosphatidyl cholines, and lipids for which fitted values for Abraham coefficients for hydrogen bond formation were available. PMID:22892357

  16. Experimental investigation of cavity flows

    Energy Technology Data Exchange (ETDEWEB)

    Loeland, Tore

    1998-12-31

    This thesis uses LDV (Laser Doppler Velocimetry), PIV (Particle Image Velocimetry) and Laser Sheet flow Visualisation to study flow inside three different cavity configurations. For sloping cavities, the vortex structure inside the cavities is found to depend upon the flow direction past the cavity. The shape of the downstream corner is a key factor in destroying the boundary layer flow entering the cavity. The experimental results agree well with numerical simulations of the same geometrical configurations. The results of the investigations are used to find the influence of the cavity flow on the accuracy of the ultrasonic flowmeter. A method to compensate for the cavity velocities is suggested. It is found that the relative deviation caused by the cavity velocities depend linearly on the pipe flow. It appears that the flow inside the cavities should not be neglected as done in the draft for the ISO technical report on ultrasonic flowmeters. 58 refs., 147 figs., 2 tabs.

  17. Solubility and speciation of actinides in salt solutions and migration experiments of intermediate level waste in salt formations

    International Nuclear Information System (INIS)

    A comprehensive study into the solubility of the actinides americium and plutonium in concentrated salt solutions, the release of radionuclides from various forms of conditioned ILW and the migration behaviour of these nuclides through geological material specific to the Gorleben site in Lower Saxony is described. A detailed investigation into the characterization of four highly concentrated salt solutions in terms of their pH, Eh, inorganic carbon contents and their densities is given and a series of experiments investigating the solubility of standard americium(III) and plutonium(IV) hydroxides in these solutions is described. Transuranic mobility studies for solutions derived from the standard hydroxides through salt and sand have shown the presence of at least two types of species present of widely differing mobility; one migrating with approximately the same velocity as the solvent front and the other strongly retarded. Actinide mobility data are presented and discussed for leachates derived from the simulated ILW in cement and data are also presented for the migration of the fission products in leachates derived from real waste solidified in cement and bitumen. Relatively high plutonium mobilities were observed in the case of the former and in the case of the real waste leachates, cesium was found to be the least retarded. The sorption of ruthenium was found to be largely associated with the insoluble residues of the natural rock salt rather than the halite itself. (orig./RB)

  18. Formation of a 25 mol% Fe2O3-Al2O3 solid solution prepared by ball milling

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Mørup, Steen; Linderoth, Søren

    1996-01-01

    The phase transformation process of a 25 mol% Fe2O3-Al2O3 powder mixture during high-energy ball milling has been studied by x-ray diffraction and Mossbauer spectroscopy. A metastable solid solution of 25 mol % Fe2O3 in Al2O3 with corundum structure has successfully been prepared after a milling...

  19. Cadmium(II) complex formation with selenourea and thiourea in solution: an XAS and 113Cd NMR study.

    Science.gov (United States)

    Jalilehvand, Farideh; Amini, Zahra; Parmar, Karnjit

    2012-10-15

    The complexes formed in methanol solutions of Cd(CF(3)SO(3))(2) with selenourea (SeU) or thiourea (TU), for thiourea also in aqueous solution, were studied by combining (113)Cd NMR and X-ray absorption spectroscopy. At low temperature (~200 K), distinct (113)Cd NMR signals were observed, corresponding to CdL(n)(2+) species (n = 0-4, L = TU or SeU) in slow ligand exchange. Peak integrals were used to obtain the speciation in the methanol solutions, allowing stability constants to be estimated. For cadmium(II) complexes with thione (C═S) or selone (C═Se) groups coordinated in Cd(S/Se)O(5) or Cd(S/Se)(2)O(4) (O from MeOH or CF(3)SO(3)(-)) environments, the (113)Cd chemical shifts were quite similar, within 93-97 ppm and 189-193 ppm, respectively. However, the difference in the chemical shift for the Cd(SeU)(4)(2+) (578 pm) and Cd(TU)(4)(2+) (526 ppm) species, with CdSe(4) and CdS(4) coordination, respectively, shows less chemical shielding for the coordinated Se atoms than for S, in contrast to the common trend with increasing shielding in the following order: O > N > Se > S. In solutions dominated by mono- and tetra-thiourea/selenourea complexes, their coordination and bond distances could be evaluated by Cd K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy. At ~200 K and high excess of thiourea, a minor amount (up to ~30%) of [Cd(TU)(5-6)](2+) species was detected by an upfield shift of the (113)Cd NMR signal (up to 423 ppm) and an amplitude reduction of the EXAFS oscillation. The amount was estimated by fitting linear combinations of simulated EXAFS spectra for [Cd(TU)(4)](2+) and [Cd(TU)(6)](2+) complexes. At room temperature, [Cd(TU)(4)](2+) was the highest complex formed, also in aqueous solution. Cd L(3)-edge X-ray absorption near edge structure (XANES) spectra of cadmium(II) thiourea solutions in methanol were used to follow changes in the CdS(x)O(y) coordination. The correlations found from the current and previous studies between (113

  20. Enthalpies of formation of CaAl4O7 and CaAl12O19 (hibonite) by high temperature, alkali borate solution calorimetry

    Science.gov (United States)

    Geiger, C. A.; Kleppa, O. J.; Grossman, L.; Mysen, B. O.; Lattimer, J. M.

    1988-01-01

    Enthalpies of formation were determined for two calcium aluminate phases, CaAl4O7 and CaAl12O19, using high-temperature alkali borate solution calorimetry. The aluminates were synthesized by multiple-cycle heating and grinding stoichiometric mixtures of CaCO3 and Al2O3, and the products were characteized by X-ray diffraction and SEM microbeam analysis. The data on impurities (CaAl4O7 was found to be about 89.00 percent pure by weight and the CaAl12O19 samples about 91.48 percent pure) were used to correct the heat of solution values of the synthetic products. The enthalpies of formation, at 1063 K, from oxides, were found to be equal to -(25.6 + or - 4.7) kJ/g.f.w. for CaAl4O7 and -(33.0 + or - 9.7) kJ/g.f.w. for CaAl12O19; the respective standard enthalpies of formation from elements, at 298 K, were estimated to be -4007 + or - 5.2 kJ/g.f.w. and -10,722 + or - 12 kJ/g.f.w.

  1. Standard partial molar heat capacities and enthalpies of formation of aqueous aluminate under hydrothermal conditions from integral heat of solution measurements

    International Nuclear Information System (INIS)

    Highlights: • Heats of solution of NaAlO2(s) were measured at five temperatures up to 250 °C. • Standard molar enthalpies of solution were determined from the measured heats of solution. • Standard molar enthalpies of solution were correlated with the density model. • The density model allows us to determine the standard molar heat capacities of reaction. - Abstract: Heats of solution of sodium aluminum oxide, NaAlO2(s), were measured in aqueous sodium hydroxide solutions using a Tian–Calvet heat-flow calorimeter (Setaram, Model C80) with high pressure “batch cells” made of hastelloy C-276, at five temperatures from (373.15 to 523.15) K, steam saturation pressure, and concentrations from (0.02 to 0.09) mol · kg−1. Standard molar enthalpies of solution, ΔsolnH∘, and relative standard molar enthalpies, [H∘(T) − H∘(298.15 K)], of NaAl(OH)4(aq) were determined from the measured heats of solution. The results were fitted with the “density” model. The temperature dependence of ΔsolnH∘ from the model yielded the standard molar heat capacities of reaction, ΔsolnCp∘, from which standard partial molar heat capacities for aqueous aluminate, Cp∘[A1(OH)4−,aq], were calculated. Standard partial molar enthalpies of formation, ΔfH∘, and entropies, S∘, of A1(OH)4−(aq) were also determined. The values for Cp∘[A1(OH)4−,aq] agree with literature data determined up to T = 413 K from enthalpy of solution and heat capacity measurements to within the combined experimental uncertainties. They are consistent with differential heat capacity measurements up to T = 573 K from Schrödle et al. (2010) [29] using the same calorimeter, but this method has the advantage that measurements could be made at much lower concentrations in the presence of an excess concentration of ligand. To our knowledge, these are the first standard partial molar heat capacities measured under hydrothermal conditions by the integral heat of solution method in a

  2. XI International conference Problems of solvation and complex formation in solutions, and VI Conference of young scientists Theoretical and experimental chemistry of liquid-phase systems (Krestovsky readings). Summary of reports

    International Nuclear Information System (INIS)

    The collection contains materials of plenary, sectional and poster sessions, presented at the XI International conference Problems of solvation and complex formation in solutions, and VI Conference of young scientists Theoretical and experimental chemistry of liquid-phase systems (Krestovsky readings). Theoretical questions and new experimental methods of chemistry of solutions, structure and dynamics of molecular and ion-molecular systems in solution and at the phase boundary; modern aspects of applied chemistry of solutions are discussed

  3. An on-line data acquisition system of oscilloscope-embedded input/output controller for cavity BPM measurement

    International Nuclear Information System (INIS)

    Cavity beam position monitor (BPM) is widely used in a precise electron beam position measurement. Based on high performance oscilloscope-embedded EPICS input/output controller, we developed an on-line cavity BPM signal processing system for fast data acquisition solution when designing a cavity BPM. Also, methods for extracting the position information from cavity pickup signals and calibration algorithm are included in this solution. (authors)

  4. Spinning process variables and polymer solution effects in the die-swell phenomenon during hollow fiber membranes formation

    Directory of Open Access Journals (Sweden)

    Pereira C.C.

    2000-01-01

    Full Text Available During hollow fiber spinning many variables are involved whose effects are still not completely clear. However, its understanding is of great interest because the control of these variables may originate membranes with the desired morphologies and physical properties. In this work, the phase inversion process induced by the immersion precipitation technique was applied to prepare hollow fibers membranes. It was verified that some of the variables involved, can promote a visco-elastic polymer solution expansion, called die-swell phenomenon, which is undesired since it may lead to low reproducibility of the permeation properties. The effects of the distance between spinneret and precipitation bath, the bore liquid composition, and the polymer solution composition were analyzed and discussed in order to avoid this phenomenon. According to the results, it was verified that the parameters investigated might promote a delay precipitation, which restrained the visco-elastic expansion.

  5. Formation and Dynamics of Ion-Stabilized Gas Nanobubble Phase in the Bulk of Aqueous NaCl Solutions.

    Science.gov (United States)

    Bunkin, Nikolai F; Shkirin, Alexey V; Suyazov, Nikolay V; Babenko, Vladimir A; Sychev, Andrey A; Penkov, Nikita V; Belosludtsev, Konstantin N; Gudkov, Sergey V

    2016-02-25

    Ion-stabilized gas nanobubbles (the so-termed "bubstons") and their clusters are investigated in bulk aqueous solutions of NaCl at different ion concentrations by four independent laser diagnostic methods. It turned out that in the range of NaCl concentration 10(-6) stirrer at different stirring rates. Different regimes of the bubston generation, resulting from various techniques of processing the liquid samples, were explored. PMID:26849451

  6. Formation of porous SnS nanoplate networks from solution and their application in hybrid solar cells.

    Science.gov (United States)

    Rath, T; Gury, L; Sánchez-Molina, I; Martínez, L; Haque, S A

    2015-06-25

    Herein, we present a facile solution-based route towards nanostructured, hybrid absorber layers based on tin mono-sulfide (SnS), an emerging, non-toxic absorber material for low-cost and large-scale PV applications. Charge photogeneration properties in the hybrid system are studied using transient absorption spectroscopy and fabricated solar cells show efficient photocurrent generation over a broad spectral range. PMID:26016404

  7. SPS accelerating cavity

    CERN Multimedia

    1983-01-01

    See photo 8302397: View from the downstream end of one of the SPS accelerating cavities (200 MHz, travelling wave structure). See 7603195 and 8011289 for more details, 7411032 for the travelling wave structure, and also 8104138. Giacomo Primadei stands on the left.

  8. LEP superconducting cavity

    CERN Multimedia

    1995-01-01

    Engineers work in a clean room on one of the superconducting cavities for the upgrade to the LEP accelerator, known as LEP-2. The use of superconductors allow higher electric fields to be produced so that higher beam energies can be reached.

  9. Cavity launchers for ICRF

    International Nuclear Information System (INIS)

    A type of resonant coil cavity is analyzed as a launcher for ICRF. This approach offers the advantages of: (1) convenient and flexible sizing, (2) ease of operation and maintenance, and (3) high power handling capability. We present results for resonance conditions, mode structures, power handling capabilities, and sensitivity to variation in plasma parameters

  10. Statistical electromagnetics: Complex cavities

    NARCIS (Netherlands)

    Naus, H.W.L.

    2008-01-01

    A selection of the literature on the statistical description of electromagnetic fields and complex cavities is concisely reviewed. Some essential concepts, for example, the application of the central limit theorem and the maximum entropy principle, are scrutinized. Implicit assumptions, biased choic

  11. What's a Cavity?

    Science.gov (United States)

    ... and deeper over time. Cavities are also called dental caries (say: KARE-eez), and if you have a ... made up mostly of the germs that cause tooth decay. The bacteria in your mouth make acids and when plaque clings to your teeth, the acids can eat away at the outermost ...

  12. Niobium superconducting cavity

    CERN Multimedia

    1980-01-01

    This 5-cell superconducting cavity, made from bulk-Nb, stems from the period of general studies, not all directed towards direct use at LEP. This one is dimensioned for 1.5 GHz, the frequency used at CEBAF and also studied at Saclay (LEP RF was 352.2 MHz). See also 7908227, 8007354, 8209255, 8210054, 8312339.

  13. Continuous formation of N-chloro-N,N-dialkylamine solutions in well-mixed meso-scale flow reactors.

    Science.gov (United States)

    Blacker, A John; Jolley, Katherine E

    2015-01-01

    The continuous flow synthesis of a range of organic solutions of N,N-dialkyl-N-chloramines is described using either a bespoke meso-scale tubular reactor with static mixers or a continuous stirred tank reactor. Both reactors promote the efficient mixing of a biphasic solution of N,N-dialkylamine in organic solvent, and aqueous sodium hypochlorite to achieve near quantitative conversions, in 72-100% in situ yields, and useful productivities of around 0.05 mol/h with residence times from 3 to 20 minutes. Initial calorimetric studies have been carried out to inform on reaction exotherms, rates and safe operation. Amines which partition mainly in the organic phase require longer reaction times, provided by the CSTR, to compensate for low mass transfer rates in the biphasic system. The green metrics of the reaction have been assessed and compared to existing procedures and have shown the continuous process is improved over previous procedures. The organic solutions of N,N-dialkyl-N-chloramines produced continuously will enable their use in tandem flow reactions with a range of nucleophilic substrates. PMID:26734089

  14. Continuous formation of N-chloro-N,N-dialkylamine solutions in well-mixed meso-scale flow reactors

    Directory of Open Access Journals (Sweden)

    A. John Blacker

    2015-12-01

    Full Text Available The continuous flow synthesis of a range of organic solutions of N,N-dialkyl-N-chloramines is described using either a bespoke meso-scale tubular reactor with static mixers or a continuous stirred tank reactor. Both reactors promote the efficient mixing of a biphasic solution of N,N-dialkylamine in organic solvent, and aqueous sodium hypochlorite to achieve near quantitative conversions, in 72–100% in situ yields, and useful productivities of around 0.05 mol/h with residence times from 3 to 20 minutes. Initial calorimetric studies have been carried out to inform on reaction exotherms, rates and safe operation. Amines which partition mainly in the organic phase require longer reaction times, provided by the CSTR, to compensate for low mass transfer rates in the biphasic system. The green metrics of the reaction have been assessed and compared to existing procedures and have shown the continuous process is improved over previous procedures. The organic solutions of N,N-dialkyl-N-chloramines produced continuously will enable their use in tandem flow reactions with a range of nucleophilic substrates.

  15. Formation of fractals by the self-assembly of interpolymer adducts of polymethacrylic acid with complementary polymers in aqueous solution

    Indian Academy of Sciences (India)

    Kandhasamy Durai Murugan; Arlin Jose Amali; Paramasivam Natarajan

    2012-03-01

    Interpolymer adducts of poly(methacrylic acid), (PMAA), with poly(vinylpyrrolidone) in presence of sodium chloride or potassium chloride form highly ordered fractal patterns in films on glass surface on drying at ambient temperature. The structure, morphology and the conditions under which the formation of fractal patterns occurs were investigated by SEM, EDX and confocal microscopic techniques. Self-organization of PMAA with complementary polymers such as poly(vinylpyrrolidone) is well-known and in the presence of sodium chloride formation of the fractals in films of the adducts is a novel observation. Fractal formation occurs due to the aggregation of interpolymer adducts. The composition of the fractals in the film is studied by EDX and confocal microscopic images of the fluorophores covalently bound to PMAA. In presence of salts, sodium chloride or potassium chloride, micellar like entities of 80 nm size were formed which further aggregate to form fractal patterns. It is suggested that the fractals result from the interpolymer adduct by Diffusion Limited Aggregation mechanism.

  16. Modeling the competition between solid solution formation and cation exchange on the retardation of aqueous radium in an idealized bentonite column

    International Nuclear Information System (INIS)

    Clays and clay rocks are considered viable geotechnical barriers in radioactive waste disposal. One reason for this is the propensity for cation exchange reactions in clay minerals to retard the migration of radionuclides. Although another retardation mechanism, namely the incorporation of radionuclides into sulfate or carbonate solid solutions, has been known for a long time, only recently has it been examined systematically. In this work, we investigate the competitive effect of both mechanisms on the transport of radium (Ra) in the near-field of a low- and intermediate level nuclear waste repository. In our idealized geochemical model, numerical simulations show that barium (Ba) and strontium (Sr) needed for Ra sulfate solid solutions also partition to the cation exchange sites of montmorillonite (Mont), which is the major mineral constituent of bentonite that is used for tunnel backfill. At high Mont content, most Ra tends to attach to Mont, while incorporation of Ra in sulfate solid solutions is more important at low Monte content. To explore the effect of the Mont content on the transport of radium, a multi-component reactive transport model was developed and implemented in the scientific software OpenGeoSys-GEM. It was found that a decrease of fixation capacity due to low Mont content is compensated by the formation of solid solutions and that the migration distance of aqueous Ra is similar at different Mont/water ratios. (author)

  17. Implosion of the small cavity and large cavity cannonball targets

    International Nuclear Information System (INIS)

    Recent results of cannonball target implosion research are briefly reviewed with theoretical predictions for GEKKO XII experiments. The cannonball targets are classified into two types according to the cavity size ; small cavity and large cavity. The compression mechanisms of the two types are discussed. (author)

  18. Flow measurement in a Joule-heating cavity with sloping bottom by using ultrasonic velocity profiler

    International Nuclear Information System (INIS)

    Flow behavior in a sloping bottom cavity is observed to study the effect of cavity shape on flow behavior. In the post study, a simple cubic cavity is applied to study the chaotic flow behavior of Joule-heating convection due to simplification. In this study, a sloping bottom cavity of the dimension one-fifth of the actual melter is applied to study the detail flow behavior. Carbon electrodes and top cooling surface are placed to make Joule-heating and the chaotic flow behavior. The working fluid is 80%wt Glycerol-water solution with LiCl as electrolyte. To observe the chaotic flow behavior spatio-temporally, Ultrasonic Velocity Profiler (UVP) is applied in this experiment to obtain the one-dimensional continuous velocity profiles in the center line of cavity. Particle Image Velocity (PIV) method is also applied to observe the two-dimensional flow behavior and to examine the cross-check between UVP and PIV for the chaotic flow behavior with temperature distribution. The flow profile between past cubic cavity and sloping bottom cavity when voltage magnitude or the temperature of cooling side are changed is compared to analyze the effect of cavity shape in Joule-heating cavity. The flow behavior in the sloping bottom cavity is similar to that in the cubic cavity in the experiment in whole cavity, but just observe the top of the sloping cavity, the range down-flow achieved is larger than the cubic cavity. (author)

  19. Seamless/bonded niobium cavities

    Science.gov (United States)

    Singer, W.

    2006-07-01

    Technological aspects and performance of seamless cavities produced by hydroforming are presented. Problems related to the fabrication of seamless cavities from bulk niobium are mainly solved thanks to the progress of the last years. The highest achieved accelerating gradients are comparable for both seamless and welded versions (ca. 40 MV/m) Nevertheless further development of seamless cavities is desirable in order to avoid the careful preparation of parts for welding and get reliable statistic. Fabrication of NbCu clad cavities from bimetallic tubes is an interesting option that gives new opportunity to the seamless technique. On the one hand it allows reducing the niobium costs contribution; on the other hand it increases the thermal stability of the cavity. The highest accelerating gradient achieved on seamless NbCu clad single cell cavities (ca. 40 MV/m) is comparable to the one reached on bulk Nb cavities. Fabrication of multi-cell NbCu cavities by hydroforming was recently proven.

  20. The electromagnetic Casimir effect of spherical cavity

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The Casimir effect results from the zero-point energy of vacuum. A spherical cavity can be divided into three regions, and we make an analysis of every region and then give a formal solution of Casimir energy. The zeta-function regularization is also used to dispel the divergence of the summation. At the end, we can see the Casimir effect of a single sphere is included in our results.

  1. Formation of cage-like particles by poly(amino acid)-based block copolymers in aqueous solution.

    OpenAIRE

    Cudd, A; Bhogal, M; O'Mullane, J; Goddard, P.

    1991-01-01

    When dissolved in N,N-dimethylformamide and then dialyzed against phosphate-buffered saline, A-B-A block copolymers composed of poly [N5-(2-hydroxyethyl)-L-glutamine]-block-poly(gamma-benzyl-L-glutamate)- block-poly [N5-(2-hydroxyethyl)-L-glutamine] form particles. The particles are cage-like structures with average diameters of 300 nm (average polydispersity, 0.3-0.5). They are stable in aqueous solution at 4 degrees C for up to 3 weeks, at which time flocculation becomes apparent. Negative ...

  2. Changeability of Oral Cavity Environment

    OpenAIRE

    Surdacka, Anna; Strzyka³a, Krystyna; Rydzewska, Anna

    2007-01-01

    Objectives In dentistry, the results of in vivo studies on drugs, dental fillings or prostheses are routinely evaluated based on selected oral cavity environment parameters at specific time points. Such evaluation may be confounded by ongoing changes in the oral cavity environment induced by diet, drug use, stress and other factors. The study aimed to confirm oral cavity environment changeability. Methods 24 healthy individuals aged 20–30 had their oral cavity environment prepared by having p...

  3. EFFECTS OF NATURAL ORIFICE SECRETIONS IN PERITONEAL CAVITY IN THE BACKGROUND OF NATURAL ORIFICE TRANSLUMINAL ENDOSCOPIC SURGERY (NOTES AN EXPERIMENTAL STUDY IN ANIMALS

    Directory of Open Access Journals (Sweden)

    Devendra

    2015-03-01

    Full Text Available Natural Orifice Transluminal Endoscopic Surgery (NOTES is a new form of minimally invasive surgery which eliminates traditional skin incisions by accessing internal body cavities through natural orifices. In our experimental animal study, we compared the incidences intraperitoneal abscess formation , culture swab of peritoneal cavity positive for organism, intraperitoneal adhesion formation and mean adhesion score before and after lavaging the portal of entry of albino rat , i.e. transgastric and transvaginal. On vaginal route as a portal of entry into peritoneal cavity , on the 7th day , 66% rats developed abscesses , 88% rats had culture swab positive and 88% rats developed intraperitoneal adhesion (grade - 2 before any cleansing of vaginal cavity with antiseptic solution . Now after lavage with povidone iodine solution, only 11% developed abscesses , 22% were peritoneal swab culture positive and 33% had interbowel and parietal adhesion of (grade 0 - 1. On 21 st day , the complication observed was adhesion formation in pre lavage group of 66% incidence and 16% after vaginal lavage. The incidence of complications were reduced significantly after lavage with antiseptic solution as shown by p values (p<0.01 for abscess formation, p< 0.01 for culture positivity and p< 0.01 for adhesions formation. Also the mean adhesion scoring was significantly reduced (p <0.02 after vaginal lavage on the 7 th day. Gastric route as the portal of entry into the peritoneal cavity, again the same variables were compared on the 7th and the 21st day , but wash was given with antibiotic solution (Cefazolin. On the 7th day , 44% had abscesses, 77% were culture positive and 66% had adhesions (Grade 1 - 2 before gastric lavage with antibiotic solution . After wash of stomach, 11% were culture positive and 44% developed adhesions (Grade 0 - 1. Here, abscess formation (p<0.02 and mean adhesion scoring (p<0.05 were significantly reduced after stomach wash. On the 21st day

  4. Hollow waveguide cavity ringdown spectroscopy

    Science.gov (United States)

    Dreyer, Chris (Inventor); Mungas, Greg S. (Inventor)

    2012-01-01

    Laser light is confined in a hollow waveguide between two highly reflective mirrors. This waveguide cavity is used to conduct Cavity Ringdown Absorption Spectroscopy of loss mechanisms in the cavity including absorption or scattering by gases, liquid, solids, and/or optical elements.

  5. Mechanism simulation of H2O2 formation by γ-rays irradiation in boric acid solution

    International Nuclear Information System (INIS)

    The mechanism reaction analysis of boric aid solutions up to temperature of 150oC was done to understand the reaction mechanism, so the further action for reducing the diluted oxygen in cooling system can be determined. The analysis was done by using fitting method between experimental and simulation results by Facsimilesoftware. The inputs data is one of the probable scheme reactions in aeration boric acid which is irradiated by using γ-rays including the rate constants, G-value, doses and the temperature dependence systems concentration. The unknown rate constant at high temperature is calculated by using the activation energy of 3 kcal. From the fitting simulation, it is known that the presence of proton and oxygen in the solution will in crease the oxidizer of H2O2 production 10 times, but higher oxygen concentration of 1μM will not give the significant effect anymore. The most reactive species for oxygen degradation is H radical at 25oC. The fraction reaction of H atom and oxygen increase 10 times higher at 150oC. The degradation reaction of oxygen by hydrated electron at 150oC become significant. From the fitting simulation, it is known that the reaction between boric acid and hydrogen peroxide degradation species such OH and H was assumed to be occurred with the rate constants of 6 magnitude

  6. Electrochemical deposition of cadmium sulfide thin films from organic solution I. Sulfur reduction and cadmium-polysulfide complex formation

    Energy Technology Data Exchange (ETDEWEB)

    Mondon, F.

    1985-02-01

    The reduction of sulfur in an aprotic solvent (DMSO) is known to be a two-stage process; each stage involves a bielectronic electrochemical step followed by a chemical dismutation reaction. When reduction is performed at a rotating electrode, it is shown that the electrochemical steps alone are involved in the electrode process. The voltammetric waves then correspond to the simple scheme 1st wave: S/sub 8/ + 2e/sup -/ ..-->.. S/sub 8//sup 2 -/ 2nd wave: S/sub 8//sup 2 -/ + 2e/sup -/ ..-->.. 2S/sub 4//sup 2 -/ The slower dismutation reactions appear only in the bulk of solution. They lead to electron number which differ from 2 when S/sub 8/ is electrolyzed. The addition of Cd/sup 2 -/ ions to a polysulfide ion solution yields soluble polysulfide-cadmium 2:1 complexes (Cd(S /SUB x/ )/sub 2/)/sup 2 -/ with /chi/ = 8, 6, and 4. The stability of the complex is increased when /chi/ decreases from 8 to 4, which leads to dismutation and exchange reactions between complexes, polysulfide ions, and sulfur.

  7. Mineral catalysis of the formation of the phosphodiester bond in aqueous solution - The possible role of montmorillonite clays

    Science.gov (United States)

    Ferris, James P.; Ertem, Gozen; KAMALUDDIN; Agarwal, Vipin; Hua, Lu Lin

    1989-01-01

    The possible role of montmorillonite clays in the spontaneous formation on the primitive earth of the phosphodiester bond in the presence of water was investigated in experiments measuring the binding of various nucleosides and nucleotides with Na(+)-montmorillonite 22A and the reactions of these compounds with a water-soluble carbodiimide. It was found that, at neutral pH, adenine derivatives bind stronger than the corresponding uracil derivatives, consistent with the protonation of the adenine by the acidic clay surface and a cationic binding of the protonated ring to the anionic clay surface. The reaction of the 5-prime-AMP with carbodiimide resulted in the formation of 2-prime,5-prime-pApA (18.9 percent), 3-prime,5-prime-pApA (11 percent), and AppA (4.8 percent). The yields of these oligomers obtained when poly(U) was used in place of the clay were 15.5 percent, 3.7 percent, and 14.9 percent AppA, respectively.

  8. Protostar Formation in Magnetic Molecular Clouds beyond Ion Detachment: I. Formulation of the Problem and Method of Solution

    CERN Document Server

    Tassis, K; Tassis, Konstantinos; Mouschovias, Telemachos Ch.

    2007-01-01

    We formulate the problem of the formation of magnetically supercritical cores in magnetically subcritical parent molecular clouds, and the subsequent collapse of the cores to high densities, past the detachment of ions from magnetic field lines and into the opaque regime. We employ the six-fluid MHD equations, accounting for the effects of grains (negative, positive and neutral) including their inelastic collisions with other species. We do not assume that the magnetic flux is frozen in any of the charged species. We derive a generalized Ohm's law that explicitly distinguishes between flux advection (and the associated process of ambipolar diffusion) and Ohmic dissipation, in order to assess the contribution of each mechanism to the increase of the mass-to-flux ratio of the central parts of a collapsing core and possibly to the resolution of the magnetic flux problem of star formation. We show how our formulation is related to and can be transformed into the traditional, directional formulation of the general...

  9. Difference in surface reactions between titanium and zirconium in Hanks' solution to elucidate mechanism of calcium phosphate formation on titanium using XPS and cathodic polarization

    Energy Technology Data Exchange (ETDEWEB)

    Tsutsumi, Y.; Nishimura, D.; Doi, H.; Nomura, N. [Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062 (Japan); Hanawa, T., E-mail: hanawa.met@tmd.ac.jp [Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062 (Japan)

    2009-06-01

    Titanium and zirconium were immersed in Hanks' solution with and without calcium and phosphate ions, and the surfaces were characterized with X-ray photoelectron spectroscopy (XPS) to determine the mechanism of calcium phosphate formation on titanium in simulated body fluids and in a living body. In addition, they were cathodically polarized in the above solutions. XPS characterization and cathodic polarization revealed differences in the surface properties in the ability of calcium phosphate formation between titanium and zirconium. The surface oxide film on titanium is not completely oxidized and is relatively reactive; that on zirconium is more passive and protective than that on titanium. Neither calcium nor phosphate stably exists alone on titanium, and calcium phosphate is naturally formed on it; calcium phosphate formed on titanium is stable and protective. On the other hand, calcium is never incorporated on zirconium, while zirconium phosphate, which is easily formed on zirconium, is highly stable and protective. Our study presents new information regarding the surface property of titanium and demonstrates that the characteristics of titanium and zirconium may be applied to various medical devices and new surface modification techniques.

  10. Difference in surface reactions between titanium and zirconium in Hanks' solution to elucidate mechanism of calcium phosphate formation on titanium using XPS and cathodic polarization

    International Nuclear Information System (INIS)

    Titanium and zirconium were immersed in Hanks' solution with and without calcium and phosphate ions, and the surfaces were characterized with X-ray photoelectron spectroscopy (XPS) to determine the mechanism of calcium phosphate formation on titanium in simulated body fluids and in a living body. In addition, they were cathodically polarized in the above solutions. XPS characterization and cathodic polarization revealed differences in the surface properties in the ability of calcium phosphate formation between titanium and zirconium. The surface oxide film on titanium is not completely oxidized and is relatively reactive; that on zirconium is more passive and protective than that on titanium. Neither calcium nor phosphate stably exists alone on titanium, and calcium phosphate is naturally formed on it; calcium phosphate formed on titanium is stable and protective. On the other hand, calcium is never incorporated on zirconium, while zirconium phosphate, which is easily formed on zirconium, is highly stable and protective. Our study presents new information regarding the surface property of titanium and demonstrates that the characteristics of titanium and zirconium may be applied to various medical devices and new surface modification techniques.

  11. In situ synchrotron X-ray diffraction study of scale formation during CO2 corrosion of carbon steel in sodium and magnesium chloride solutions

    International Nuclear Information System (INIS)

    Highlights: ► We studied the scale formation processes of carbon steel in CO2 saturated brine at 80 °C. ► Protective scales were formed in all tests. ► Only FeCO3 formed in saturated brine while Fe(OH)2CO3 detected with presence of MgCl2. ► MgCl2 accelerates the onset of siderite precipitation. - Abstract: In situ synchrotron X-ray diffraction was used to follow the formation of corrosion products on carbon steel in CO2 saturated NaCl solution and mixed NaCl/magnesium chloride (MgCl2) at 80 °C. Siderite (FeCO3) was the only phase formed in NaCl solution, while Fe(OH)2CO3 was also detected when MgCl2 was present. The proposed model is that siderite precipitation, occurring once the critical supersaturation was exceeded within a defined boundary layer, caused local acidification which accelerated the anodic dissolution of iron. The current fell once a complete surface scale was formed. It is suggested that MgCl2 addition decreased the required critical supersaturation for precipitation.

  12. Femtosecond X-ray solution scattering reveals that bond formation mechanism of a gold trimer complex is independent of excitation wavelength.

    Science.gov (United States)

    Kim, Kyung Hwan; Kim, Jong Goo; Oang, Key Young; Kim, Tae Wu; Ki, Hosung; Jo, Junbeom; Kim, Jeongho; Sato, Tokushi; Nozawa, Shunsuke; Adachi, Shin-Ichi; Ihee, Hyotcherl

    2016-07-01

    The [Au(CN)2 (-)]3 trimer in water experiences a strong van der Waals interaction between the d(10) gold atoms due to large relativistic effect and can serve as an excellent model system to study the bond formation process in real time. The trimer in the ground state (S0) exists as a bent structure without the covalent bond between the gold atoms, and upon the laser excitation, one electron in the antibonding orbital goes to the bonding orbital, thereby inducing the formation of a covalent bond between gold atoms. This process has been studied by various time-resolved techniques, and most of the interpretation on the structure and dynamics converge except that the structure of the first intermediate (S1) has been debated due to different interpretations between femtosecond optical spectroscopy and femtosecond X-ray solution scattering. Recently, the excitation wavelength of 267 nm employed in our previous scattering experiment was suggested as the culprit for misinterpretation. Here, we revisited this issue by performing femtosecond X-ray solution scattering with 310 nm excitation and compared the results with our previous study employing 267 nm excitation. The data show that a linear S1 structure is formed within 500 fs regardless of excitation wavelength and the structural dynamics observed at both excitation wavelengths are identical to each other within experimental errors. PMID:27191012

  13. Positronium formation and reactions in water, ice and aqueous solutions seen by positron age-momentum correlation

    International Nuclear Information System (INIS)

    The high counting rate correlation measurements between the positron age at the instant of annihilation and the momentum of the center of mass of the positron-electron pair were carried out in pure water, ice and some aqueous solutions of MnSO4, KMnO4 and FeCl3. The self annihilation of initially formed para-positronium, the self annihilation of the converted para-positronium from ortho-positronium, the pick-off annihilation of ortho-positronium and the free annihilation of positrons were clearly separated. It was found that the momentum distribution of the self annihilation of converted positronium is significantly narrower than that of initially formed para-positronium. This fact means that initially formed para-positroniums are not completely thermalized but converted ones undergo a complete thermalization. (Auth.)

  14. Colloquium: cavity optomechanics

    CERN Multimedia

    2011-01-01

    Monday 14 November 2011, 17:00 Ecole de Physique, Auditoire Stueckelberg Université de Genève Cavity optomechanics: controlling micro mechanical oscillators with laser light Prof. Tobias Kippenberg EPFL, Lausanne Laser light can be used to cool and to control trapped ions, atoms and molecules at the quantum level. This has lead to spectacular advances such as the most precise atomic clocks. An outstanding frontier is the control with lasers of nano- and micro-mechancial systems. Recent advances in cavity optomechanics have allowed such elementary control for the first time, enabling mechanical systems to be ground state cooled leading to readout with quantum limited sensitivity and permitting to explore new device concepts resulting from radiation pressure.  

  15. Formation of hexagonal boron nitride nanoscrolls induced by inclusion and exclusion of self-assembling molecules in solution process

    Science.gov (United States)

    Hwang, Da Young; Suh, Dong Hack

    2014-05-01

    Unlike nanoscrolls of 2D graphene, those of 2D h-BN have not been demonstrated, except for only a few experimental reports. Nanoscrolls of h-BN with high yields and reproducibility are first synthesized by a simple solution process. Inner-tube diameters of BNSs including LCAs, N-(2-aminoethyl)-3α-hydroxy-5β-cholan-24-amide, a bile acid derivative and self-assembling material, can be controlled by adjusting the diameter of the LCA fiber which is grown by self-assembly. TEM and SEM images show that BNSs have a tube-like morphology and the inner-tube diameter of BNSs can be controlled in the range from 20 to 60 nm for a smaller diameter, up to 300 nm for a larger diameter by LCA fiber growth inside the BNSs. Finally, open cylindrical BNSs with hollow cores were obtained by dissolving LCAs inside BNSs.Unlike nanoscrolls of 2D graphene, those of 2D h-BN have not been demonstrated, except for only a few experimental reports. Nanoscrolls of h-BN with high yields and reproducibility are first synthesized by a simple solution process. Inner-tube diameters of BNSs including LCAs, N-(2-aminoethyl)-3α-hydroxy-5β-cholan-24-amide, a bile acid derivative and self-assembling material, can be controlled by adjusting the diameter of the LCA fiber which is grown by self-assembly. TEM and SEM images show that BNSs have a tube-like morphology and the inner-tube diameter of BNSs can be controlled in the range from 20 to 60 nm for a smaller diameter, up to 300 nm for a larger diameter by LCA fiber growth inside the BNSs. Finally, open cylindrical BNSs with hollow cores were obtained by dissolving LCAs inside BNSs. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00897a

  16. Bifurcation structure of an optical ring cavity

    DEFF Research Database (Denmark)

    Kubstrup, C.; Mosekilde, Erik

    1996-01-01

    One- and two-dimensional continuation techniques are applied to determine the basic bifurcation structure for an optical ring cavity with a nonlinear absorbing element (the Ikeda Map). By virtue of the periodic structure of the map, families of similar solutions develop in parameter space. Within...... the individual family, the organization of the solutions exhibit an infinite number of regulatory arranged domains, the so-called swallow tails. We discuss the origin of this structure which has recently been observed in a variety of other systems as well....

  17. Formation of poly(butyl 2-cyanoacrylate) microcapsules and the microencapsulation of aqueous solutions of [125I]-labelled proteins

    International Nuclear Information System (INIS)

    Some featrues of the polymerization reaction of butyl 2-cyanoacrylate at different aqueous/organic solvent interfaces have been investigated. In particular, the effects of pH and the presence of protein on the formation of microcapsules by in situ interfacial polymerization of butyl 2-cyanoacrylate in w/o emulsions have been studied. [125I]-labelled proteins have been used to study the procedure as a method of microencapsulating enzymes or other proteins within potentially biodegradable membranes. Preliminary in vitro degradation studies suggest that degradation of the microcapsules is inhibited by low levels of their breakdown products, thus allowing the storage of the microcapsules as aqueous suspensions for prolonged periods in sealed containers. (Auth.)

  18. Complex formation equilibria of some beta-amino-alcohols with lead(II) and cadmium(II) in aqueous solution.

    Science.gov (United States)

    Canepari, S; Carunchio, V; Castellano, P; Messina, A

    1998-12-01

    A study of complex formation equilibria of some beta-amino-alcohols with lead(II) and cadmium(II) ions at 25 degrees C and in 0.5 M KNO(3) is reported. The amino-alcohols considered are 2-amino-1-propanol, 2-amino-1-butanol, 2-amino-1-pentanol and 2-amino-1,3-propanediol. sec-Buthylamine and 2-amino-1-methoxy-propane have been also considered for comparison. The results are discussed in terms of ligand structure, paying attention to the number of hydroxyl groups and to the length of the alkyl residual. A weak contribution of the alcoholic oxygen in the coordination of cadmium(II) and the presence of a mixed hydroxyl species in lead(II) containing systems are hypothesized. PMID:18967412

  19. SANS study of micelle formation in aqueous mixed solutions of sodium and magnesium dodecylsulfates with added salts

    International Nuclear Information System (INIS)

    Complete text of publication follows. Mixtures of two anionic surfactants -sodium and magnesium didecyl sulphates- in heavy water were studied by small-angle neutron scattering (SANS) at various relative and total concentrations of the surfactants and various salt contents (NaCl and MgCl2). The average aggregation number and the effective fractional charge of mixed micelles were determined by fitting the data with the spherical or ellipsoidal shape model for the form factor and with the rescaled mean spherical approximation (RMSA) model for the structural factor. There are differences in the dependence of the characteristics of the mixed micelles formation on the relative concentration of the surfactants for the cases of their small and high total concentration. The changes in the micelle structure under salt addition are affected by the king of the salt. (author)

  20. Thermodynamics of complexes formation by ITC in methanol/water = 9/1 (v/v) solution: A case study

    Energy Technology Data Exchange (ETDEWEB)

    Fisicaro, Emilia, E-mail: emilia.fisicaro@unipr.it [University of Parma, Department of Pharmacy, Parco Area delle Scienze, 27/A, 43124 Parma (Italy); Compari, Carlotta; Bacciottini, Franco; Contardi, Laura [University of Parma, Department of Pharmacy, Parco Area delle Scienze, 27/A, 43124 Parma (Italy); Carcelli, Mauro; Rispoli, Gabriele; Rogolino, Dominga [University of Parma, Department of Chemistry, Parco Area delle Scienze, 17/A, 43124 Parma (Italy)

    2014-06-01

    Graphical abstract: Integrase strand transfert inhibitors chelate the metal ions in the active site of HIV integrase. - Highlights: • Development of inhibitors acting against those viral enzymes operating via a cooperative two-metal ion mechanism, such as HIV integrase (IN), requires optimizing the binding affinity to the target. • We have defined an experimental procedure for obtaining reliable thermodynamic data by ITC in methanol/water = 9/1 (v/v) as solvent. • Formation heats in mixed solvent of the complexes formed by a ligand, model of Raltegravir, with Mg(II), Mn(II), Co(II) and Zn(II) are here reported. - Abstract: Most enzymes that participate in the biochemistry of nucleic acids require divalent metal ion cofactors to promote activity. Development of potent inhibitors, acting against those viral enzymes operating via a cooperative two-metal ion mechanism, such as HIV integrase (IN) and RNase H, hepatitis C virus polymerase and influenza endonuclease, requires optimizing the binding affinity to the target, which is dictated by the binding free energy composed of both enthalpic and entropic contributions. They can be obtained by using isothermal titration microcalorimetry. We have defined an experimental procedure for obtaining reliable thermodynamic data in methanol/water = 9/1 0.1 M KCl as solvent, used to overcome solubility problems. In this way we have measured the heats of formation of the complexes formed by N-(4-fluorobenzyl)-5-hydroxy-2-isopropyl-1-methyl-6-oxo-1, 6-dihydroxypyrimidine-4-carboxylate (HL, a model of Raltegravir, the antiretroviral drug produced by Merck and Co.), and a series of divalent metal ions of biological interest (Mg(II), Mn(II), Co(II) and Zn(II)), whose speciation was previously determined by potentiometry.

  1. Irrigation of the abdominal cavity in the treatment of experimentally induced microbial peritonitis: Efficacy of ozonated saline

    Energy Technology Data Exchange (ETDEWEB)

    Ozmen, V.; Thomas, W.O.; Healy, J.T.; Fish, J.M.; Chambers, R.; Tacchi, E.; Nichols, R.L.; Flint, L.M.; Ferrara, J.J. (Tulane Univ. School of Medicine, New Orleans, LA (United States))

    1993-05-01

    Ozone is an oxidizing agent possessing potent in vitro microbicidal capacity. This study was designed to address the extent to which irrigation of the contaminated abdominal cavity using a saline solution primed with ozone is effective in reducing morbidity and mortality. Gelatin capsules containing different quantities of a premixed slurry of filtered human fecal material were implanted in the peritoneal cavities of a preliminary series of rats. Three inocula concentrations were selected for later experiments, based upon their ability to produce morbid consequences: (1) high (100% 1-day mortality), (2) medium (70% 3-day mortality, 100% abscess rate in survivors), and (3) low (100% 10-day survival, 100% abscess rate). Fecal and abscess bacteriology were similar in all rats. The peritoneal cavities of 240 rats then underwent fecal-capsule implantation (three groups of 80 rats/inoculum concentration). At celiotomy 4 hours later, equal numbers of rats from each group were randomly assigned to one of four protocols: (1) no irrigation, (2) normal saline irrigation, (3) saline-cephalothin irrigation, and (4) ozonated saline irrigation. Each treatment lasted 5 minutes, using 100 ml of irrigation fluid. Mortality was significantly reduced when, in lieu of no irrigation, any of the irrigation solutions were used. Additionally, ozonated saline statistically proved the most effective irrigating solution for reducing abscess formation in survivors.

  2. RF superconducting cavities

    CERN Document Server

    Kojima, Y

    1980-01-01

    The history and present activity in research on RF superconducting cavities in various countries are reviewed. The program of the July 1980 Karlsruhe workshop is reproduced and research activity in this field at Stanford HEPL and SLAC, Cornell, Oregon, Brookhaven, KEK (Japan), Weismann (Israel), Genoa, CERN and Karlsruhe (KfK) listed. The theoretical basis of surface resistance and intracavity magnetic field, multipacing and non-resonant electron loading are outlined. (20 refs).

  3. Suppression of extraneous thermal noise in cavity optomechanics

    OpenAIRE

    Zhao, Yi; Wilson, Dalziel J.; Ni, Kang-Kuen; Kimble, H. Jeff

    2012-01-01

    Extraneous thermal motion can limit displacement sensitivity and radiation pressure effects, such as optical cooling, in a cavity-optomechanical system. Here we present an active noise suppression scheme and its experimental implementation. The main challenge is to selectively sense and suppress extraneous thermal noise without affecting motion of the oscillator. Our solution is to monitor two modes of the optical cavity, each with different sensitivity to the oscillator's motion but similar ...

  4. Entangling atoms in bad cavities

    OpenAIRE

    Sorensen, Anders S.; Molmer, Klaus

    2002-01-01

    We propose a method to produce entangled spin squeezed states of a large number of atoms inside an optical cavity. By illuminating the atoms with bichromatic light, the coupling to the cavity induces pairwise exchange of excitations which entangles the atoms. Unlike most proposals for entangling atoms by cavity QED, our proposal does not require the strong coupling regime g^2/\\kappa\\Gamma>> 1, where g is the atom cavity coupling strength, \\kappa is the cavity decay rate, and \\Gamma is the dec...

  5. Cavity Backed Slot Antenna

    Directory of Open Access Journals (Sweden)

    Sarang Masani, Ila Parmar, Hitendra Jadeja

    2013-05-01

    Full Text Available Among the current driving forces in wireless communications, there is a need for compact, efficient, inexpensive and reproducible antennas. In some instances, particularly long-distance applications, radiators with directive, high-gain characteristics are necessary. This paper proposes a cavity-backed slot antenna to that end. This antenna will enhance the gain, directivity and can also be easily flush mounted to the flying object. The shape and size of the slot can be effectively utilized to get the desired result. The proposed antenna is feed by waveguide which facilitate it to be applicable at high power operation where coaxial cable fails due to skin effect. Present antenna is verified using Numerical Technique called Finite Element Method FEM. The conception of this antenna is realized by the software HFSS “Ansoft-High Frequency Structure Simulator”. By properly selecting shapes, dimensions of the slots and number of slot affects the parameters like return loss, gain along Θ, Ø directions, Cartesian plot and radiation pattern .The Backing of cavity to the slot antenna provide the basics of the gain enhancement and the slot loading effect and the cavity volume plays an important role in achieving the desired return loss at the specific frequency.The simulated antenna shows the 7.0944 db of gain and return loss of -28.60. The proposed antenna works at 6 GHz.

  6. Surgical Approaches to the Nasal Cavity and Sinuses.

    Science.gov (United States)

    Weeden, Alyssa Marie; Degner, Daniel Alvin

    2016-07-01

    The nasal cavity and sinuses may be exposed primarily via a dorsal or ventral surgical approach. Surgical planning involves the use of advanced imaging, such as computed tomography or MRI. Surgical treatment of lesions of the nasal cavity usually is limited to benign lesions or can also be used in combination with adjunctive therapy, such as radiation therapy. Extreme caution must be exercised with a dorsal approach to the nasal cavity to avoid complications of inadvertent penetration into the brain case. Gentle tissue handling and careful closure of the mucoperiosteum must be exercised following a ventral approach to minimize the risk of oronasal fistula formation. PMID:27217006

  7. Effect of ultrasonic frequency on H2O2 sonochemical formation rate in aqueous nitric acid solutions in the presence of oxygen.

    Science.gov (United States)

    Dalodière, Elodie; Virot, Matthieu; Moisy, Philippe; Nikitenko, Sergey I

    2016-03-01

    The influence of the ultrasonic frequency (20 kHz, 207 kHz, and 615 kHz) towards the formation kinetics of H2O2 under Ar and Ar/(20 vol.%)O2 atmospheres was evaluated in pure water and aqueous nitric solutions. Results obtained at low frequency ultrasound demonstrate that hydrogen peroxide formation is enhanced under an Ar/O2 gas mixture whatever the sonicated medium. Nevertheless, H2O2 yields are higher in aqueous nitric solutions whatever the nature of the saturating gas. These observations are consistent at high frequency ultrasound under Ar gas notwithstanding higher yields for H2O2. Surprisingly, an inverse tendency is observed for high frequency sonolysis carried out under an Ar/O2 atmosphere: higher yields of H2O2 are measured in pure water. Further studies in the presence of pure Ar revealed a more important decomposition of nitric acid under high frequency ultrasound leading to higher yields of both HNO2 in the liquid phase and NO in the gas phase. In the presence of Ar/O2 mixture, the intrabubble oxidation of NO causes cavitation bubble depletion in O2 leading to the drop of H2O2 yield. On the other hand, it was found that for Ar/(20 vol.%)O2 mixture there is no influence of oxygen on HNO2 yield whatever the ultrasonic frequency; this is most likely explained by two processes: (i) HNO2 formation results from nitrate-ion thermolysis in the liquid reaction zone surrounding the cavitation bubble, and (ii) effective intrabubble oxidation of NOx species by oxygen to nitrate-ion. PMID:26584999

  8. Indications of the formation of an oversaturated solid solution during hydrogenation of Mg-Ni based nanocomposite produced by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Guzman, D. [Departamento de Ingenieria en Metalurgia, Facultad de Ingenieria, Universidad de Atacama y Centro Regional de Investigacion y Desarrollo Sustentable de Atacama, CRIDESAT, Av. Copayapu 485, Copiapo (Chile); Ordonez, S. [Departamento de Ingenieria Metalurgica, Facultad de Ingenieria, Universidad de Santiago de Chile, Av. Lib. Bernardo O' Higgins 3363, Santiago (Chile); Fernandez, J.F.; Sanchez, C. [Departamento de Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain); Serafini, D. [Departamento de Fisica, Facultad de Ciencias, Universidad de Santiago de Chile and Center for Interdisciplinary Research in Materials, CIMAT, Av. Lib. Bernardo O' Higgins 3363, Santiago (Chile); Rojas, P.A. [Escuela de Ingenieria Mecanica, Facultad de Ingenieria, Av. Los Carrera 01567, Quilpue, Pontificia Universidad Catolica de Valparaiso, PUCV (Chile); Aguilar, C. [Instituto de Materiales y Procesos Termomecanicos, Facultad de Ciencias de la Ingenieria, Universidad Austral de Chile, Av. General Lagos 2086, Valdivia (Chile)

    2009-07-15

    An oversaturated solid solution of H in a nanocomposite material formed mainly by nanocrystalline Mg{sub 2}Ni, some residual nanocrystalline Ni and an Mg rich amorphous phase has been found for the first time. The nanocomposite was produced by mechanical alloying starting from Mg and Ni elemental powders, using a SPEX 8000D mill. The hydriding characterization of the nanocomposite was carried out by solid-gas reaction method in a Sievert's type apparatus. The maximum hydrogen content reached in a period of 21 Ks without prior activation was 2.00 wt.% H under hydrogen pressure of 2 MPa at 363 K. The X-ray diffraction analysis showed the presence of an oversaturated solid solution between nanocrystalline Mg{sub 2}Ni and H without any sign of Mg{sub 2}NiH{sub 4} hydride formation. The dehydriding behaviour was studied by differential scanning calorimetry and thermogravimetry. The results showed the existence of two desorption peaks, the first one associated with the transformation of the oversaturated solid solution into Mg{sub 2}NiH{sub 4}, and the second one with the Mg{sub 2}NiH{sub 4} desorption. (author)

  9. [Use of autologous blood for elimination of the residual pleural cavity after pneumonectomy].

    Science.gov (United States)

    Kariev, T M; Ibragimov, M A

    1987-09-01

    The authors describe a method of liquidation of a postresectional residual cavity by the introduction of the patient's autoblood with antibiotics. When using this method all the factors of the coagulating system of blood are involved in the formation of fibrin and the following formation of fibrothorax, which accelerates the formation of fibrothorax. The proposed method was used in 26 patients with residual pleural cavities after resection of the lungs and facilitated their liquidation and formation of fibrothorax. PMID:3441966

  10. Optical cavity resonator in an expanding universe

    Science.gov (United States)

    Kopeikin, Sergei M.

    2015-02-01

    We study the cosmological evolution of frequency of a standing electromagnetic wave in a resonant optical cavity placed to the expanding manifold described by the Robertson-Walker metric. Because of the Einstein principle of equivalence (EEP), one can find a local coordinate system (a local freely falling frame), in which spacetime is locally Minkowskian. However, due to the conformal nature of the Robertson-Walker metric the conventional transformation to the local inertial coordinates introduces ambiguity in the physical interpretation of the local time coordinate, . Therefore, contrary to a common-sense expectation, a straightforward implementation of EEP alone does not allow us to unambiguously decide whether atomic clocks based on quantum transitions of atoms, ticks at the same rate as the clocks based on electromagnetic modes of a cavity. To resolve this ambiguity we have to analyse the cavity rigidity and the oscillation of its electromagnetic modes in an expanding universe by employing the full machinery of the Maxwell equations irrespectively of the underlying theory of gravity. We proceed in this way and found out that the size of the cavity and the electromagnetic frequency experience an adiabatic drift in conformal (unphysical) coordinates as the universe expands in accordance with the Hubble law. We set up the oscillation equation for the resonant electromagnetic modes, solve it by the WKB approximation, and reduce the coordinate-dependent quantities to their counterparts measured by a local observer who counts time with atomic clock. The solution shows that there is a perfect mutual cancellation of the adiabatic drift of cavity's frequency by space transformation to local coordinates and the time counted by the clocks based on electromagnetic modes of cavity has the same rate as that of atomic clocks. We conclude that if general relativity is correct and the local expansion of space is isotropic there should be no cosmological drift of frequency of a

  11. Seismic wave interaction with underground cavities

    Science.gov (United States)

    Schneider, Felix M.; Esterhazy, Sofi; Perugia, Ilaria; Bokelmann, Götz

    2016-04-01

    Realization of the future Comprehensive Nuclear Test Ban Treaty (CTBT) will require ensuring its compliance, making the CTBT a prime example of forensic seismology. Following indications of a nuclear explosion obtained on the basis of the (IMS) monitoring network further evidence needs to be sought at the location of the suspicious event. For such an On-Site Inspection (OSI) at a possible nuclear test site the treaty lists several techniques that can be carried out by the inspection team, including aftershock monitoring and the conduction of active seismic surveys. While those techniques are already well established, a third group of methods labeled as "resonance seismometry" is less well defined and needs further elaboration. A prime structural target that is expected to be present as a remnant of an underground nuclear explosion is a cavity at the location and depth the bomb was fired. Originally "resonance seismometry" referred to resonant seismic emission of the cavity within the medium that could be stimulated by an incident seismic wave of the right frequency and observed as peaks in the spectrum of seismic stations in the vicinity of the cavity. However, it is not yet clear which are the conditions for which resonant emissions of the cavity could be observed. In order to define distance-, frequency- and amplitude ranges at which resonant emissions could be observed we study the interaction of seismic waves with underground cavities. As a generic model for possible resonances we use a spherical acoustic cavity in an elastic full-space. To solve the forward problem for the full elastic wave field around acoustic spherical inclusions, we implemented an analytical solution (Korneev, 1993). This yields the possibility of generating scattering cross-sections, amplitude spectrums and synthetic seismograms for plane incident waves. Here, we focus on the questions whether or not we can expect resonant responses in the wave field scattered from the cavity. We show

  12. Nanostructured gadolinium-doped ceria microsphere synthesis from ion exchange resin: Multi-scale in-situ studies of solid solution formation

    International Nuclear Information System (INIS)

    In the current nano-sized material revolution, the main limitations to a large-scale deployment of nanomaterials involve health concerns related to nano-dissemination via air. Developing new chemical routes benefiting from nano-size advantages while avoiding their hazards could overcome these limitations. Addressing this need, a chemical route leading to soft nano-particle agglomerates, i.e., macroscopic precursors presenting the ability to be decomposed into nano-sized materials, was developed and applied to Ce0.8Gd0.2O2−δ. Using cerium/gadolinium-loaded ion exchange resin, the Ce0.8Gd0.2O2−δ solid solution formation as a function of temperature was studied in-situ through X-ray diffraction, X-ray absorption spectroscopy and Raman spectroscopy. Temperatures corresponding to the organic skeleton decomposition and to the mixed oxide crystallization were identified. An optimal heat treatment, leading to nanostructured soft agglomerates, was established. Microsphere processing capabilities were evaluated and particle size distribution measurements were recorded. A very low fracture strength was calculated, and a nanometric particle size distribution (170 nm) was determined. - Graphical abstract: The elaboration of micro-spherical precursors leading to the formation of nano-oxide soft agglomerates was studied and approved through the use of ion exchange resin loaded with cerium and gadolinium. The formation of the solid solution was followed through in-situ measurements such as XAS, XRD, Raman, TGA and DSC. Key temperatures were identified for the formation of the mixed-oxide. Following this study, the microstructure and particle size of oxide microspheres formed highlight the formation of soft nano-arrangments. - Highlights: • Soft microspherical agglomerates able to be decomposed into nano-sized materials. • In situ study of cerium/gadolinium-loaded ion exchange resin conversion in oxide. • In situ multi-scale study through Raman spectroscopy, XAS and HT

  13. Nanostructured gadolinium-doped ceria microsphere synthesis from ion exchange resin: Multi-scale in-situ studies of solid solution formation

    Energy Technology Data Exchange (ETDEWEB)

    Caisso, Marie [CEA, DEN, DTEC/SDTC/LEMA, F-30207 Bagnols-sur-Cèze Cedex (France); Institut Européen des Membranes, UMR 5635 CNRS-ENSCM-UM2, CC047, Université Montpellier 2, F-34095 Montpellier Cedex 5 (France); Lebreton, Florent; Horlait, Denis [CEA, DEN, DTEC/SDTC/LEMA, F-30207 Bagnols-sur-Cèze Cedex (France); Picart, Sébastien [CEA, DEN, DRCP/SERA/LCAR, F-30207 Bagnols-sur-Cèze Cedex (France); Martin, Philippe M.; Bès, René [CEA, DEN, DEC/SESC/LLCC, F-13108 Saint-Paul-Lez-Durance Cedex (France); Renard, Catherine; Roussel, Pascal [Unité de Catalyse et Chimie du Solide, UMR 8012 CNRS, Ecole Nationale Supérieure de Chimie de Lille BP 90108, 59652 Villeneuve d’Ascq Cedex (France); Neuville, Daniel R. [Institut de Physique du Globe de Paris-CNRS, Géochimie and Cosmochimie, 1 rue Jussieu, 75005 Paris (France); Dardenne, Kathy; Rothe, Jörg [Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal (KIT-INE), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Delahaye, Thibaud, E-mail: thibaud.delahaye@cea.fr [CEA, DEN, DTEC/SDTC/LEMA, F-30207 Bagnols-sur-Cèze Cedex (France); Ayral, André [Institut Européen des Membranes, UMR 5635 CNRS-ENSCM-UM2, CC047, Université Montpellier 2, F-34095 Montpellier Cedex 5 (France)

    2014-10-15

    In the current nano-sized material revolution, the main limitations to a large-scale deployment of nanomaterials involve health concerns related to nano-dissemination via air. Developing new chemical routes benefiting from nano-size advantages while avoiding their hazards could overcome these limitations. Addressing this need, a chemical route leading to soft nano-particle agglomerates, i.e., macroscopic precursors presenting the ability to be decomposed into nano-sized materials, was developed and applied to Ce{sub 0.8}Gd{sub 0.2}O{sub 2−δ}. Using cerium/gadolinium-loaded ion exchange resin, the Ce{sub 0.8}Gd{sub 0.2}O{sub 2−δ} solid solution formation as a function of temperature was studied in-situ through X-ray diffraction, X-ray absorption spectroscopy and Raman spectroscopy. Temperatures corresponding to the organic skeleton decomposition and to the mixed oxide crystallization were identified. An optimal heat treatment, leading to nanostructured soft agglomerates, was established. Microsphere processing capabilities were evaluated and particle size distribution measurements were recorded. A very low fracture strength was calculated, and a nanometric particle size distribution (170 nm) was determined. - Graphical abstract: The elaboration of micro-spherical precursors leading to the formation of nano-oxide soft agglomerates was studied and approved through the use of ion exchange resin loaded with cerium and gadolinium. The formation of the solid solution was followed through in-situ measurements such as XAS, XRD, Raman, TGA and DSC. Key temperatures were identified for the formation of the mixed-oxide. Following this study, the microstructure and particle size of oxide microspheres formed highlight the formation of soft nano-arrangments. - Highlights: • Soft microspherical agglomerates able to be decomposed into nano-sized materials. • In situ study of cerium/gadolinium-loaded ion exchange resin conversion in oxide. • In situ multi-scale study

  14. On the formation and structure of rare-earth element complexes in aqueous solutions under hydrothermal conditions with new data on gadolinium aqua and chloro complexes

    Science.gov (United States)

    Mayanovic, Robert A.; Anderson, Alan J.; Bassett, William A.; Chou, I.-Ming

    2007-01-01

    (III) chloro complexes increases steadily with temperature from 0.4 ?? 0.2 to 1.7 ?? 0.3 in the 0.006m chloride solution and from 0.9 ?? 0.7 to 1.8 ?? 0.7 in the 0.1m GdCl3 aqueous solution in the 300-500????C range. Conversely, the number of H2O ligands of Gd(H2O)??-nCln+3-n complexes decreases steadily from 8.9 ?? 0.4 to 5.8 ?? 0.7 in the 0.006m GdCl3 aqueous solution and from 9.0 ?? 0.5 to 5.3 ?? 1.0 in the 0.1m GdCl3 aqueous solution at temperatures from 25 to 500????C. Analysis of our results shows that the chloride ions partially displace the inner-shell water molecules during Gd(III) complex formation under hydrothermal conditions. The Gd-OH2 bond of the partially-hydrated Gd(III) chloro complexes exhibits slightly smaller rates of length contraction (??? 0.005??A??/100????C) for both solutions. The structural aspects of chloride speciation of Gd(III) as measured from this study and of Yb(III) as measured from our previous experiments are consistent with the solubility of these and other REE in deep-sea hydrothermal fluids. ?? 2006 Elsevier B.V. All rights reserved.

  15. Pulse radiolysis of poly(vinyl methyl ether) in aqueous solution. Formation and structure of primary radicals

    International Nuclear Information System (INIS)

    The reactivity of a temperature-sensitive polymer poly(vinyl methyl ether) (PVME) towards OH, e-aq, and H atoms in aqueous solution has been investigated by pulse radiolysis. The rate constant for reaction of OH with PVME (1.2 x 105 Da) has been determined as 2.2 x 108 dm3 mol-1 s-1 by competition kinetics at 296 K. Hydrogen atoms are less reactive. The rate constant of the reaction of hydrated electrons with PVME is lower than 1.9 x 107 dm3 mol-1 s-1. Radicals of PVME formed in the reaction with OH have a featureless absorption spectrum with increasing absorption towards shorter wavelengths. Upon OH attack three kinds of radicals are generated: two at different α-positions and one at a β-position with respect to the oxygen atom. The α-radicals rapidly reduce tetranitromethane yielding the stable nitroform anion. From the yield of the latter species it is calculated that ca. 54% of the PVME radicals are formed at α-positions. Results are compared with earlier data on low-molecular-weight ethers and simple water-soluble polymers

  16. Kinetics of the formation of 2D-hexagonal silica nanostructured materials by nonionic block copolymer templating in solution.

    Science.gov (United States)

    Manet, Sabine; Schmitt, Julien; Impéror-Clerc, Marianne; Zholobenko, Vladimir; Durand, Dominique; Oliveira, Cristiano L P; Pedersen, Jan Skov; Gervais, Christel; Baccile, Niki; Babonneau, Florence; Grillo, Isabelle; Meneau, Florian; Rochas, Cyrille

    2011-10-01

    The different steps of the self-assembly in solution of several 2D-hexagonal silica nanostructured SBA-15 materials have been investigated by SAXS and SANS in situ experiments. Unique quantitative information about the shape and size evolution upon time of the micellar aggregates throughout the self-assembly process is obtained using a complete model that describes well the scattering data for the various synthesis conditions. In all cases, before the precipitation of the material, the micelles shape changes from spherical to rod-like, where the structure of the rod-like micelles is linked to the structure of the 2D-hexagonal precipitated material. In addition, the kinetics of hydrolysis of the inorganic precursor (TEOS) has been determined by in situ Raman spectroscopy. More specifically, by comparing synthesis made with different acids (HNO(3), HBr, HCl, H(2)SO(4), and H(3)PO(4)), it is found that materials prepared using the "salting-out" anions (SO(4)(2-) and H(2)PO(4)(-)) are much better ordered than with the "salting-in" anions (NO(3)(-) and Br(-)). PMID:21863844

  17. Strand break formation in plasmid DNA irradiated in aqueous solution. Effect of medium temperature and hydroxyl radical scavenger concentration

    International Nuclear Information System (INIS)

    Plasmid pBR322 DNA (4363 base pairs) in aerobic aqueous solution was irradiated with 60Co γ-radiation. The change of diffusion coefficients (D) of chemical species, rate constants (k) of radical-DNA interaction and solubilities of O2 in water cannot be ignored when a temperature varies more than a few tens of centigrade. It is important to examine the variation of the yields of DNA strand breaks as a function of temperature in order to analyze the mechanisms of DNA strand breaks from the chemical point of view. Hence, we observed the change of the yield of strand breaks with temperatures between -20 and 42degC by agarose gel electrophoresis. We also observed the change of the yield of strand breaks with the concentration of OH scavenger (Tris) from 1 mmol dm-3 to 100 mmol dm-3 and summarized it with previous experiments. This summarization indicated that the order of the lifetime of OH radical in cellular environment is several nanosecond. This value is consistent with the measurement of the lifetime of 8.7 nanosecond for OH radical in mammalian cell. (author)

  18. Density functional theory-based prediction of the formation constants of complexes of ammonia in aqueous solution: indications of the role of relativistic effects in the solution chemistry of gold(I).

    Science.gov (United States)

    Hancock, Robert D; Bartolotti, Libero J

    2005-10-01

    A prediction of the formation constants (log K1) for complexes of metal ions with a single NH3 ligand in aqueous solution, using quantum mechanical calculations, is reported. DeltaG values at 298 K in the gas phase for eq 1 (DeltaG(DFT)) were calculated for 34 metal ions using density functional theory (DFT), with the expectation that these would correlate with the free energy of complex formation in aqueous solution (DeltaG(aq)). [M(H2O)6]n+(g) + NH(3)(g) = [M(H2O)5NH3]n+(g) + H2O(g) (eq 1). The DeltaG(aq) values include the effects of complex changes in solvation on complex formation, which are not included in eq 1. It was anticipated that such changes in solvation would be constant or vary systematically with changes in the log K(1) value for different metal ions; therefore, simple correlations between DeltaG(DFT) and DeltaG(aq) were sought. The bulk of the log K1(NH3) values used to calculate DeltaG(aq) were not experimental, but estimated previously (Hancock 1978, 1980) from a variety of empirical correlations. Separate linear correlations between DeltaG(DFT) and DeltaG(aq) for metal ions of different charges (M2+, M3+, and M4+) were found. In plots of DeltaG(DFT) versus DeltaG(aq), the slopes ranged from 2.201 for M2+ ions down to 1.076 for M4+ ions, with intercepts increasing from M2+ to M4+ ions. Two separate correlations occurred for the M3+ ions, which appeared to correspond to small metal ions with a coordination number (CN) of 6 and to large metal ions with a higher CN in the vicinity of 7-9. The good correlation coefficients (R) in the range of 0.97-0.99 for all these separate correlations suggest that the approach used here may be the basis for future predictions of aqueous phase chemistry that would otherwise be experimentally inaccessible. Thus, the log K1(NH3) value for the transuranic Lr3+, which has a half-life of 3.6 h in its most stable isotope, is predicted to be 1.46. These calculations should also lead to a greater insight into the factors

  19. Effect of total aluminum concentration on the formation and transformation of nanosized Al13 and Al30 in hydrolytic polymeric aluminum aqueous solutions

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhaoyang; LIU Changjun; LUAN Zhaokun; ZHANG Zhongguo; LI Yanzhong; JIA Zhiping

    2005-01-01

    Influence of total aluminum concentration (CAlT) on the generation and transformation of nanosized Al13 and Al30 in hydrolytic polyaluminum aqueous solutions was investigated using high field 27Al NMR and time-developed Al-Ferron complex colorimetry. When prepared at the optimal basicity (B) of Al13 generation and 80℃, the Al13 species in polyaluminum solution tends to further polymerize and convert to Al30 and higher polymers when CAlT >0.2 mol·L-1, but Al13 does not convert to Al30 quantificationally, as the formation of Alu from Al13 and Al30 is accelerated in the same way. The conversion rate of Al13 is accelerated by the increase in CAlT. When CAlT >0.75 mol·L-1, Al13 content decreases rapidly, and Al30 content increases continuously and becomes the dominant nanometer polynuclear aluminum species. Alm is one of prerequisites of Al13 conversion to Al30. When CAlT increases and B reduces, the polymerization rate between Al13 and Alm increases, and at the same time, the dissociation reaction rate of Al13 and Al30 by H+ also increases. The latter becomes the dominant reaction in polyaluminum solution with low B value, so Al30 decreases with the increasing CAlT. The hydrolytic polyaluminum solution with Al13 content beyond 80% can only be prepared under the condition of CAlT<0.5 mol·L-1 and optimal B value.

  20. Formation of solid solutions of gallium in Fe–Cr and Fe–Co alloys: Mössbauer studies and first-principles calculations

    International Nuclear Information System (INIS)

    Highlights: • Structure features of the formation of quasibinary solid solutions Fe–Co–Ga and Fe–Cr–Ga are found. • The first-principles calculation of mixing and solubility energies for Ga in an Fe–X alloy are given. • Ga handicaps the processes of phase separation in the Fe–Cr system and ordering in the Fe–Co system. • Preference of Ga entering in the neighborhood of a second element can help study multielement alloys. - Abstract: Investigation of Ga influence on the structure of Fe–Cr and Fe–Co alloys was performed with the use of Mössbauer spectroscopy and X-ray diffraction methods. The experimental results are compared with results of first-principles calculations of the mixing and solubility energies for Ga in an Fe–X (X = Co, Cr) alloy both in ferromagnetic and paramagnetic states. It is shown that Ga mainly goes into the solid solutions of the base alloys. In the alloys of the Fe–Cr system, doping with Ga handicaps the decomposition of solid solutions, observed in the binary alloys, and increases its stability. In the alloys with Co, Ga also favors the uniformity of solid solutions. The results of the first-principles calculations testify in favor of a preferable dissolution of Ga in the FeCo regions of a multicomponent structure rather than FeCr regions, both types of regions being in the ferromagnetic state at the temperature of annealing. The analysis of Mössbauer experiments gives some grounds to conclude that if, owing to liquation, clusterization, or initial stages of phase separation, there exist regions enriched in iron, some amount of Ga atoms prefer to enter the nearest surroundings of iron atoms, thus forming binary Fe–Ga regions (or phases)

  1. In situ morphology studies of the mechanism for solution additive effects on the formation of bulk heterojunction films

    KAUST Repository

    Richter, Lee J.

    2014-09-29

    The most successful active film morphology in organic photovoltaics is the bulk heterojunction (BHJ). The performance of a BHJ arises from a complex interplay of the spatial organization of the segregated donor and acceptor phases and the local order/quality of the respective phases. These critical morphological features develop dynamically during film formation, and it has become common practice to control them by the introduction of processing additives. Here, in situ grazing incidence X-ray diffraction (GIXD) and grazing incidence small angle X-ray scattering (GISAXS) studies of the development of order in BHJ films formed from the donor polymer poly(3-hexylthiophene) and acceptor phenyl-C61-butyric acid methyl ester under the influence of two common additives, 1,8-octanedithiol and 1-chloronaphthalene, are reported. By comparing optical aggregation to crystallization and using GISAXS to determine the number and nature of phases present during drying, two common mechanisms by which the additives increase P3HT crystallinity are identified. Additives accelerate the appearance of pre-crystalline nuclei by controlling solvent quality and allow for extended crystal growth by delaying the onset of PCBM-induced vitrification. The glass transition effects vary system-to-system and may be correlated to the number and composition of phases present during drying. Synchrotron X-ray scattering measurements of nanoscale structure evolution during the drying of polymer-fullerene photovoltaic films are described. Changes in the number and nature of phases, as well as the order within them, reveals the mechanisms by which formulation additives promote structural characteristics leading to higher power conversion efficiencies.

  2. ISR RF cavities

    CERN Multimedia

    1983-01-01

    In each ISR ring the radiofrequency cavities were installed in one 9 m long straight section. The RF system of the ISR had the main purpose to stack buckets of particles (most of the time protons)coming from the CPS and also to accelerate the stacked beam. The installed RF power per ring was 18 kW giving a peak accelerating voltage of 20 kV. The system had a very fine regulation feature allowing to lower the voltage down to 75 V in a smooth and well controlled fashion.

  3. Reaction of dithiothreitol and para-nitroacetophenone with different radical precursors of .OH radical-induced strand break formation of single-stranded DNA in anoxic aqueous solution

    International Nuclear Information System (INIS)

    The yields of single-strand breakage (ssb) in single-stranded calf thymus DNA (ssDNA) have been determined after 60Co γ-irradiation of aqueous anoxic solutions in the presence of different concentrations of dithiothreitol (DTT), ascorbate or trans-4,5-dihydroxy-1,2-dithiane, using low-angle laser light scattering. The influence of DTT on the kinetics of ssb formation has been determined by conductivity measurements in pulse radiolysis. The results suggest that strand breakage in ssDNA proceeds via two modes of about equal contribution and with half-lives of about 7 ms and 0.8 s, respectively. Both modes reflect reactions of at least two DNA radicals, which react with DTT by hydrogen-atom transfer reactions with similar rate constants of about 5-9 x 105dm3mol-1s-1. (Author)

  4. Formation of OH radicals from radical cations of some substituted benzenes in aqueous solutions at 800 C and at room temperature: effect of oxygen

    International Nuclear Information System (INIS)

    The reactions of a number of simple substituted-benzene radical cations with water at 800 C and at room temperature have been investigated. The radical cations were produced by thermal decomposition of Na2S2O8. The authors searched for the formation of OH radicals, which they identified by their reaction with nitrobenzene to give nitrophenols. The thermal decomposition of peroxydisulfate in deoxygenated, nitrobenzene-saturated aqueous solutions of chlorobenzene, bromobenzene, and tert-butylbenzene gave o- and p-nitrophenols, whereas fluorobenzene, iodobenzene, phenol, and chlorophenols gave no nitrophenols. With nitrobenzene alone, no nitrophenols were obtained. The structural requirements for the reaction of aromatic radical cations with water to produce OH radicals are discussed. In the presence of oxygen, the yield of chlorophenols and bromophenols increased dramatically, producing mainly the para isomer, but in the bromobenzene case also significant amounts of m-bromophenol. The mechanism of this oxidation is discussed. 3 tables

  5. The free radical chemistry of tert-butyl formate: rate constants for hydroxyl radical, hydrated electron and hydrogen atom reaction in aqueous solution

    International Nuclear Information System (INIS)

    Transients generated in situ by advanced oxidation technologies (AOTs) to destroy organic contaminants in ground and drinking water often give large concentrations of chemical by-products. These by-products may have adverse health effects, and can also interfere with the desired chemical removal by competing for the generated transients, thus lowering the overall efficiency of the remediation process. To allow for a quantitative evaluation of the influence of tert-butyl formate (TBF), a major by-product formed in the AOT destruction of methyl tert-butyl ether, rate constants for TBF reaction with the hydroxyl radical, the hydrated electron and the hydrogen atom in aqueous solution were measured in this study. Absolute values of (5.23±0.07)x108, (5.48±0.09)x108 and (3.58±0.07)x106 M-1 s-1, were determined at 22 deg. C, respectively

  6. Parametric instabilities in the LCGT arm cavity

    Science.gov (United States)

    Yamamoto, K.; Uchiyama, T.; Miyoki, S.; Ohashi, M.; Kuroda, K.; Numata, K.

    2008-07-01

    We evaluated the parametric instabilities of LCGT (Japanese interferometric gravitational wave detector project) arm cavity. The number of unstable modes of LCGT is 10-times smaller than that of Advanced LIGO (USA). Since the strength of the instabilities of LCGT depends on the mirror curvature more weakly than that of Advanced LIGO, the requirement of the mirror curvature accuracy is easier to be achieved. The difference in the parametric instabilities between LCGT and Advanced LIGO is because of the thermal noise reduction methods (LCGT, cooling sapphire mirrors; Advanced LIGO, fused silica mirrors with larger laser beams), which are the main strategies of the projects. Elastic Q reduction by the barrel surface (0.2 mm thickness Ta2O5) coating is effective to suppress instabilities in the LCGT arm cavity. Therefore, the cryogenic interferometer is a smart solution for the parametric instabilities in addition to thermal noise and thermal lensing.

  7. Parametric instabilities in the LCGT arm cavity

    CERN Document Server

    Yamamoto, K; Miyoki, S; Ohashi, M; Kuroda, K; Numata, K

    2008-01-01

    We evaluated the parametric instabilities of LCGT (Japanese interferometric gravitational wave detector project) arm cavity. The number of unstable modes of LCGT is 10-times smaller than that of Advanced LIGO (U.S.A.). Since the strength of the instabilities of LCGT depends on the mirror curvature more weakly than that of Advanced LIGO, the requirement of the mirror curvature accuracy is easier to be achieved. The difference in the parametric instabilities between LCGT and Advanced LIGO is because of the thermal noise reduction methods (LCGT, cooling sapphire mirrors; Advanced LIGO, fused silica mirrors with larger laser beams), which are the main strategies of the projects. Elastic Q reduction by the barrel surface (0.2 mm thickness Ta$_2$O$_5$) coating is effective to suppress instabilities in the LCGT arm cavity. Therefore, the cryogenic interferometer is a smart solution for the parametric instabilities in addition to thermal noise and thermal lensing.

  8. Postirradiation flap infection about the oral cavity

    International Nuclear Information System (INIS)

    Postirradiation alteration of oral flora is well documented in the literature. Infection as a complication leading to partial or complete loss of a flap used to reconstruct a defect in the oral cavity is a worrisome outcome. We describe how a flap that was judged clinically to be viable became overwhelmingly infected with the Klebsiella oxytoca, an oral cavity pathogen encountered in this patient following irradiation. Local and systemic changes led to detachment of the flap. This complication may be explained, in view of the absence of venous congestion or arterial ischemia both clinically and pathologically, by the proven contamination of the flap by the Klebsiella pathogen. Local factors resulted in lower resistance and subsequent overwhelming infection. Discussion of the case, review of pertinent literature, and proposed solutions are presented

  9. Absorption spectrum of monomeric pseudoisocyanine: A new perspective and its implications for formation and spectral response of J-aggregates in solution and in thin films

    International Nuclear Information System (INIS)

    We argued against the current spectral assignment for absorption spectrum of monomeric PIC which is widely accepted since the pioneering works of Scheibe and Jelley [G. Scheibe, Angew. Chem. 49 (1936) 563; E.E. Jelly, Nature 138 (1936) 1009]. A new spectrum is presented along with its conceptual basis. The hypothesized spectrum attributes the previous 0-0 (∼525 nm) and 0-1 (∼490 nm) assignments, respectively, to intermediates acting as the precursor of J-aggregates and to the 0-0 transition of monomeric PIC and brings the spectrum in accord with the seemingly universal spectral fingerprint of cyanines. The hypothesis is used to analyze and interpret the temperature dependence of the UV-vis absorption of PIC aggregates in saline aqueous solution by incorporating the J-band simulations within frenkel exciton formalism. Its implications for aggregate formation kinetics are given on the basis of current spectroscopic evidence. The hypothesis readily answers several long-standing questions: Why compared to many other cyanines at least an order of magnitude higher dye concentration is needed to form J-aggregates of PIC? Why are there no precursors, since aggregation is expected to be a consecutive process? A large number of observations on steady-state and time-resolved spectral properties, and aggregation kinetics in solution/thin films are likely to find reasonable explanations within this hypothesis

  10. Absorption spectrum of monomeric pseudoisocyanine: A new perspective and its implications for formation and spectral response of J-aggregates in solution and in thin films

    Energy Technology Data Exchange (ETDEWEB)

    Guelen, Demet [Physics Department, Middle East Technical University (METU), 06531 Ankara (Turkey)], E-mail: dgul@metu.edu.tr; Ozcelik, Serdar [Chemistry Department, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)

    2008-05-15

    We argued against the current spectral assignment for absorption spectrum of monomeric PIC which is widely accepted since the pioneering works of Scheibe and Jelley [G. Scheibe, Angew. Chem. 49 (1936) 563; E.E. Jelly, Nature 138 (1936) 1009]. A new spectrum is presented along with its conceptual basis. The hypothesized spectrum attributes the previous 0-0 ({approx}525 nm) and 0-1 ({approx}490 nm) assignments, respectively, to intermediates acting as the precursor of J-aggregates and to the 0-0 transition of monomeric PIC and brings the spectrum in accord with the seemingly universal spectral fingerprint of cyanines. The hypothesis is used to analyze and interpret the temperature dependence of the UV-vis absorption of PIC aggregates in saline aqueous solution by incorporating the J-band simulations within frenkel exciton formalism. Its implications for aggregate formation kinetics are given on the basis of current spectroscopic evidence. The hypothesis readily answers several long-standing questions: Why compared to many other cyanines at least an order of magnitude higher dye concentration is needed to form J-aggregates of PIC? Why are there no precursors, since aggregation is expected to be a consecutive process? A large number of observations on steady-state and time-resolved spectral properties, and aggregation kinetics in solution/thin films are likely to find reasonable explanations within this hypothesis.

  11. Frequency control of radiofrequency cavity

    OpenAIRE

    Menart, Jure

    2014-01-01

    This work describes the design, development and application of the system for frequency control of EMMA accelerator radiofrequency cavity. The problem with the radiofrequency cavities is, that because of various factors (change in the environmental temperature, mechanical stress, ...), they are continuously frequency detuning. The consequence of the frequency detuning is that electromagnetic field in the cavity is not optimal for the acceleration of the particles. For this reason the resonant...

  12. Formation of Microcracks During Micro-Arc Oxidation in a Phytic Acid-Containing Solution on Two-Phase AZ91HP

    Science.gov (United States)

    Zhang, R. F.; Chang, W. H.; Jiang, L. F.; Qu, B.; Zhang, S. F.; Qiao, L. P.; Xiang, J. H.

    2016-04-01

    Micro-arc oxidation (MAO) is an effective method to produce ceramic coatings on magnesium alloys and can considerably improve their corrosion resistance. The coating properties are closely related with microcracks, which are always inevitably developed on the coating surface. In order to find out the formation and development regularity of microcracks, anodic coatings developed on two-phase AZ91HP after different anodizing times were fabricated in a solution containing environmentally friendly organic electrolyte phytic acid. The results show that anodic film is initially developed on the α phase. At 50 s, anodic coatings begin to develop on the β phase, evidencing the formation of a rough area. Due to the coating successive development, the microcracks initially appear at the boundary between the initially formed coating on the α phase and the subsequently developed coating on the β phase. With the prolonging treatment time, the microcracks near the β phase become evident. After treating for 3 min, the originally rough area on the β phase disappears and the coatings become almost uniform with microcracks randomly distributed on the sample surface. Inorganic phosphates are found in MAO coatings, suggesting that phytate salts are decomposed due to the high instantaneous temperature on the sample surface resulted from spark discharge.

  13. The properties of squeezed optical states created in lossy cavities

    CERN Document Server

    Seifoory, Hossein; Dignam, Marc M; Sipe, J E

    2016-01-01

    We investigate theoretically the properties of squeezed states generated using degenerate parametric down conversion in lossy cavities. We show that the Lindblad master equation, which governs the evolution of this system, has as its solution a squeezed thermal state with an effective temperature and squeezing parameter that depends on time. We derive analytical solutions for the time-evolution of quadrature noise, thermal photon number, squeezing parameter, and total photon number under different pumping regimes. We also find the steady state limits of the quadrature noises and discuss the $ g^{(2)} $ factor of the generated light inside the cavity in the steady state.

  14. Fresnel reflection from a cavity with net roundtrip gain

    International Nuclear Information System (INIS)

    A planewave incident on an active etalon with net roundtrip gain may be expected to diverge in field amplitude, yet applying the Fresnel formalism to Maxwell's equations admits a convergent solution. We describe this solution mathematically and provide additional insight by demonstrating the response of such a cavity to an incident beam of light. Cavities with net roundtrip gain have often been overlooked in the literature, and a clear understanding of their behavior yields insight to negative refraction in nonmagnetic media, a duality between loss and gain, amplified total internal reflection, and the negative-index lens

  15. Fresnel reflection from a cavity with net roundtrip gain

    Energy Technology Data Exchange (ETDEWEB)

    Mansuripur, Tobias S., E-mail: mansuripur@physics.harvard.edu [Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States); Mansuripur, Masud [College of Optical Sciences, The University of Arizona, Tucson, Arizona 85721 (United States)

    2014-03-24

    A planewave incident on an active etalon with net roundtrip gain may be expected to diverge in field amplitude, yet applying the Fresnel formalism to Maxwell's equations admits a convergent solution. We describe this solution mathematically and provide additional insight by demonstrating the response of such a cavity to an incident beam of light. Cavities with net roundtrip gain have often been overlooked in the literature, and a clear understanding of their behavior yields insight to negative refraction in nonmagnetic media, a duality between loss and gain, amplified total internal reflection, and the negative-index lens.

  16. Single ion cavity QED experiments

    International Nuclear Information System (INIS)

    Full text: We have set up a spherical Paul trap for a storing a single Ca+ ion placed in the center of a high finesse near confocal resonator. We report on experiments demonstrating the coupling of the narrow S1/2-D5/2 transition to the cavity internal light field. Due to the coupling, the ion acts as sensitive probe for the cavity internal field. We are able to map the field distribution by measuring the excitation probability. Scanning the cavity over the resonance imprints a Doppler frequency shift on the cavity field which leads to a spectral shift and a asymmetric broadening of the S-D transition. (author)

  17. Cavity coalescence in superplastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Stowell, M.J.; Livesey, D.W.; Ridley, N.

    1984-01-01

    An analysis of the probability distribution function of particles randomly dispersed in a solid has been applied to cavitation during superplastic deformation and a method of predicting cavity coalescence developed. Cavity size distribution data were obtained from two microduplex nickel-silver alloys deformed superplastically to various extents at elevated temperature, and compared to theoretical predictions. Excellent agreement occurred for small void sizes but the model underestimated the number of voids in the largest size groups. It is argued that the discrepancy results from a combination of effects due to non-random cavity distributions and to enhanced growth rates and incomplete spheroidization of the largest cavities.

  18. Surface state photonic bandgap cavities

    OpenAIRE

    Rahachou, A. I.; Zozoulenko, I. V.

    2005-01-01

    We propose and analyze a new type of a resonant high-Q cavity for lasing, sensing or filtering applications, which is based on a surface states of a finite photonic crystal. We demonstrate that such the cavity can have a Q factor comparable with that one of conventional photonic band-gap defect mode cavities. At the same time, the distinguished feature of the surface mode cavity is that it is situated directly at the surface of the photonic crystal. This might open up new possibilities for de...

  19. Nanofriction in Cavity Quantum Electrodynamics.

    Science.gov (United States)

    Fogarty, T; Cormick, C; Landa, H; Stojanović, Vladimir M; Demler, E; Morigi, Giovanna

    2015-12-01

    The dynamics of cold trapped ions in a high-finesse resonator results from the interplay between the long-range Coulomb repulsion and the cavity-induced interactions. The latter are due to multiple scatterings of laser photons inside the cavity and become relevant when the laser pump is sufficiently strong to overcome photon decay. We study the stationary states of ions coupled with a mode of a standing-wave cavity as a function of the cavity and laser parameters, when the typical length scales of the two self-organizing processes, Coulomb crystallization and photon-mediated interactions, are incommensurate. The dynamics are frustrated and in specific limiting cases can be cast in terms of the Frenkel-Kontorova model, which reproduces features of friction in one dimension. We numerically recover the sliding and pinned phases. For strong cavity nonlinearities, they are in general separated by bistable regions where superlubric and stick-slip dynamics coexist. The cavity, moreover, acts as a thermal reservoir and can cool the chain vibrations to temperatures controlled by the cavity parameters and by the ions' phase. These features are imprinted in the radiation emitted by the cavity, which is readily measurable in state-of-the-art setups of cavity quantum electrodynamics. PMID:26684118

  20. Weak Langmuir optical turbulence in a fiber cavity

    Science.gov (United States)

    Xu, G.; Garnier, J.; Mussot, A.; Trillo, S.; Churkin, D.; Tarasov, N.; Turitsyn, S.; Picozzi, A.

    2016-07-01

    We study theoretically and numerically the dynamics of a passive optical fiber ring cavity pumped by a highly incoherent wave: an incoherently injected fiber laser. The theoretical analysis reveals that the turbulent dynamics of the cavity is dominated by the Raman effect. The forced-dissipative nature of the fiber cavity is responsible for a large diversity of turbulent behaviors: Aside from nonequilibrium statistical stationary states, we report the formation of a periodic pattern of spectral incoherent solitons, or the formation of different types of spectral singularities, e.g., dispersive shock waves and incoherent spectral collapse behaviors. We derive a mean-field kinetic equation that describes in detail the different turbulent regimes of the cavity and whose structure is formally analogous to the weak Langmuir turbulence kinetic equation in the presence of forcing and damping. A quantitative agreement is obtained between the simulations of the nonlinear Schrödinger equation with cavity boundary conditions and those of the mean-field kinetic equation and the corresponding singular integrodifferential reduction, without using adjustable parameters. We discuss the possible realization of a fiber cavity experimental setup in which the theoretical predictions can be observed and studied.

  1. Modeling Coupled Evaporation and Seepage in Ventilated Cavities

    International Nuclear Information System (INIS)

    Cavities excavated in unsaturated geological formations are important to activities such as nuclear waste disposal and mining. Such cavities provide a unique setting for simultaneous occurrence of seepage and evaporation. Previously, inverse numerical modeling of field liquid-release tests and associated seepage into cavities were used to provide seepage-related large-scale formation properties by ignoring the impact of evaporation. The applicability of such models was limited to the narrow range of ventilation conditions under which the models were calibrated. The objective of this study was to alleviate this limitation by incorporating evaporation into the seepage models. We modeled evaporation as an isothermal vapor diffusion process. The semi-physical model accounts for the relative humidity, temperature, and ventilation conditions of the cavities. The evaporation boundary layer thickness (BLT) over which diffusion occurs was estimated by calibration against free-water evaporation data collected inside the experimental cavities. The estimated values of BLT were 5 to 7 mm for the open underground drifts and 20 mm for niches closed off by bulkheads. Compared to previous models that neglected the effect of evaporation, this new approach showed significant improvement in capturing seepage fluctuations into open cavities of low relative humidity. At high relative-humidity values (greater than 85%), the effect of evaporation on seepage was very small

  2. Two-cavity gyroklystron with self-excited input cavity

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, E.V.; Zasypkin, E.V. [Inst. of Applied Physics, Novgorod (Russian Federation)

    1995-12-31

    A new type of gyro-oscillator-two cavity gyroklystron with self-excited input cavity (or, for simplicity, two-cavity gyrokylstron oscillator) is proposed. In this device, the autooscillations excited in the first cavity modulate electrons by energy, electrons are bunched in the drift space, and then the bunches excite powerful oscillations in the second (output) cavity. Since, as in gyroklystron, the optimal second cavity length L{sub 2} does not exceed 2-2.5 {lambda} ({lambda} is the operating wavelength), its Q-factor Q{sub 2} {approximately} (L{sub 2}/{lambda}){sup 2} should be essentially lower than cavity Q-factor of a traditional gyrotron. It allows to diminish the RF ohmic losses in the second cavity and to enhance the output power without the efficiency reduction. A simplest theory of such oscillator has been developed. Predicted by theory, the output power enhancement (in comparison with that for an ordinary gyrotron) has been demonstrated experimentally.

  3. Frequency Tuning for a DQW Crab Cavity

    CERN Document Server

    Verdú-Andrés, Silvia; Ben-Zvi, Ilan; Calaga, Rama; Capatina, Ofelia; Leuxe, Raphael; Skaritka, John; Wu, Qiong; Xiao, Binping; Zanoni, Carlo

    2016-01-01

    The nominal operating frequency for the HL-LHC crab cavities is 400.79 MHz within a bandwidth of ±60kHz. Attaining the required cavity tune implies a good understanding of all the processes that influence the cavity frequency from the moment when the cavity parts are being fabricated until the cavity is installed and under operation. Different tuning options will be available for the DQW crab cavity of LHC. This paper details the different steps in the cavity fabrication and preparation that may introduce a shift in the cavity frequency and introduces the different tuning methods foreseen to bring the cavity frequency to meet the specifications.

  4. A Scanning Cavity Microscope

    CERN Document Server

    Mader, Matthias; Hänsch, Theodor W; Hunger, David

    2014-01-01

    Imaging of the optical properties of individual nanosystems beyond fluorescence can provide a wealth of information. However, the minute signals for absorption and dispersion are challenging to observe, and only specialized techniques requiring sophisticated noise rejection are available. Here we use signal enhancement in a scanning optical microcavity to demonstrate ultra-sensitive imaging. Harnessing multiple interactions of probe light with a sample within an optical resonator, we achieve a 1700-fold signal enhancement compared to diffraction-limited microscopy. We demonstrate quantitative imaging of the extinction cross section of gold nanoparticles with a sensitivity below 1 nm2, we show a method to improve spatial resolution potentially below the diffraction limit by using higher order cavity modes, and we present measurements of the birefringence and extinction contrast of gold nanorods. The demonstrated simultaneous enhancement of absorptive and dispersive signals promises intriguing potential for opt...

  5. Plasmonic mediated nucleation of resonant nano-cavities in metallic layers

    OpenAIRE

    Karpov, V. G.; Nardone, M.; Subashiev, A. V.

    2012-01-01

    We predict plasmonic mediated nucleation of pancake shaped resonant nano-cavities in metallic layers that are penetrable to laser fields. The underlying physics is that the cavity provides a narrow plasmonic resonance that maximizes its polarizability in an external field. The resonance yields a significant energy gain making the formation of such cavities highly favorable. Possible implications include nano-optics and generation of the dielectric bits in conductive films that underlie the ex...

  6. Superconducting cavity model for LEP

    CERN Multimedia

    1979-01-01

    A superconducting cavity model is being prepared for testing in a vertical cryostat.At the top of the assembly jig is H.Preis while A.Scharding adjusts some diagnostic equipment to the cavity. See also photo 7912501X.

  7. Fiber cavities for atom chips

    OpenAIRE

    Klappauf, B.G.; Horak, P.; Kazansky, P. G.

    2003-01-01

    We present experimental realizations of several micro-cavities, constructed from standard fiber optic components, which meet the theoretical criteria for single atom detection from laser-cooled samples. We discuss integration of these cavities into state-of-the-art 'atom chips'.

  8. Design of a cavity filter

    International Nuclear Information System (INIS)

    A cavity filter was developed for the SSRF 0-mode beam feedback. The filter is used to pick up the 500 MHz signal from the storage ring beam. The Superfish was used to simulate the model of the cavity bandpass filter. The design method, parameters of the filter and results of beam measurements are described in this paper. (authors)

  9. Study on superconducting accelerating cavities

    International Nuclear Information System (INIS)

    A test cavity of cylindrical shape has been designed and constructed to study superconducting accelerating cavities for TRISTAN e+e- Ring. Higher order modes have been calculated by using SUPERFISH program and an analytical method, and measured. The measured resonant frequencies well agree with the calculated results. (author)

  10. Technical tasks in superconducting cavities

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Kenji [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

    1997-11-01

    The feature of superconducting rf cavities is an extremely small surface resistance on the wall. It brings a large energy saving in the operation, even those are cooled with liquid helium. That also makes possible to operate themselves in a higher field gradient comparing to normal conducting cavities, and brings to make accelerators compact. These merits are very important for the future accelerator engineering which is planed at JAERI for the neutron material science and nuclear waste transmutation. This machine is a high intensity proton linac and uses sc cavities in the medium and high {beta} sections. In this paper, starting R and D of proton superconducting cavities, several important technical points which come from the small surface resistance of sc cavities, are present to succeed it and also differences between the medium and high - {beta} structures are discussed. (author)

  11. Mechanical Properties of Niobium Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Dhakal, Pashupati [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Matalevich, Joseph R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Myneni, Ganapati Rao [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2015-09-01

    The mechanical stability of bulk Nb cavity is an important aspect to be considered in relation to cavity material, geometry and treatments. Mechanical properties of Nb are typically obtained from uniaxial tensile tests of small samples. In this contribution we report the results of measurements of the resonant frequency and local strain along the contour of single-cell cavities made of ingot and fine-grain Nb of different purity subjected to increasing uniform differential pressure, up to 6 atm. Measurements have been done on cavities subjected to different heat treatments. Good agreement between finite element analysis simulations and experimental data in the elastic regime was obtained with a single set of values of Young’s modulus and Poisson’s ratio. The experimental results indicate that the yield strength of medium-purity ingot Nb cavities is higher than that of fine-grain, high-purity Nb.

  12. Natural convection in three-dimensional porous cavities: integral transform method

    Energy Technology Data Exchange (ETDEWEB)

    Luz Neto, H. [Instituto Nacional de Tecnologia, INT/MCT, Ministerio de Ciencia e Tecnologia, Rio de Janeiro (Brazil); Quaresma, J.N.N. [Universidade Federal do Para (Brazil). Chemical Engineering Dept.; Cotta, R.M. [Universidade Federal do Rio de Janeiro (Brazil). Mechanical Engineering Dept.

    2002-07-01

    A transient three-dimensional Darcy model of natural convection in porous medium filled cavities is studied, using a vorticity-vector potential formulation and the generalized integral transform technique (GITT). A general formulation and solution methodology for vertical cavities (insulated vertical walls with differential horizontal wall temperatures) is developed. Results for cubic cavities are presented while evaluating the Rayleigh number effects for stable situations, observing the transient evolution of the heat transfer process. The convergence behavior of the proposed eigenfunction expansion solution is investigated and comparisons with previously reported steady-state solutions are critically performed. (author)

  13. Machining of cavities for travelling wave LINAC

    International Nuclear Information System (INIS)

    A Traveling Wave (T.W.), 2π/3 mode electron linear accelerator of 2856 MHz is under development at CAT for radiation processing of agricultural products. This LINAC consists of a thermionic triode electron gun, TW buncher section and Regular Section. Machining of input/output couplers, regular section cells and disc were carried out using CNC lathe LAL- 2 BT and CNC milling machine BMV - 40. This paper highlights the dimensional and geometrical requirements of cavities, problems encountered during machining of OFE copper and their solutions to achieve high precision with ultrahigh surface finish. The performance of Linac depends upon a number of factors such as operating vacuum level, accuracies of cavity dimensions, materials, and surface finish of cavities comprising the LINAC. Each of these depends upon material and fabrication techniques used for manufacturing OFE copper of higher purity has been used since they offer lower surface resistivity and lower power losses. With CNC tuning and milling machines, the high surface finish has been achieved with higher dimensional and geometrical accuracies

  14. Solution Conditions Affect the Ability of the K30D Mutation To Prevent Amyloid Fibril Formation by Apolipoprotein C-II: Insights from Experiments and Theoretical Simulations.

    Science.gov (United States)

    Mao, Yu; Todorova, Nevena; Zlatic, Courtney O; Gooley, Paul R; Griffin, Michael D W; Howlett, Geoffrey J; Yarovsky, Irene

    2016-07-12

    Apolipoproteins form amphipathic helical structures that bind lipid surfaces. Paradoxically, lipid-free apolipoproteins display a strong propensity to form cross-β structure and self-associate into disease-related amyloid fibrils. Studies of apolipoprotein C-II (apoC-II) amyloid fibrils suggest that a K30-D69 ion pair accounts for the dual abilities to form helix and cross-β structure. Consistent with this is the observation that a K30D mutation prevents fibril formation under standard fibril forming conditions. However, we found that fibril formation by K30D apoC-II proceeded readily at low pH and a higher salt or protein concentration. Structural analysis demonstrated that K30D apoC-II fibrils at pH 7 have a structure similar to that of the wild-type fibrils but are less stable. Molecular dynamics simulations of the wild-type apoC-II fibril model at pH 7 and 3 showed that the loss of charge on D69 at pH 3 leads to greater separation between residues K30 and D69 within the fibril with a corresponding reduction in β-strand content around residue 30. In contrast, in simulations of the K30D mutant model at pH 7 and 3, residues D30 and D69 moved closer at pH 3, accompanied by an increase in β-strand content around residue 30. The simulations also demonstrated a strong dominance of inter- over intramolecular contacts between ionic residues of apoC-II and suggested a cooperative mechanism for forming favorable interactions between the individual strands under different conditions. These observations demonstrate the important role of the buried K30-D69 ion pair in the stability and solution properties of apoC-II amyloid fibrils. PMID:27311794

  15. Admissible thermal loading in geological formations. Consequences on radioactive waste disposal methods

    International Nuclear Information System (INIS)

    The thermal loading in salt formation is studied for the disposal of high-level radioactive waste embedded in glass. Temperature effect on glass leaching, stability of gel layer on glass surface, quantity of leaching solution available in the borehole and corrosion resistance of materials used for containers are examined. The geological storage medium must satisfy particularly complex requirements: stratigraphy, brine migration, permeability, fissuring, mechanical strength, creep, thermal expansion, cavity structure ..

  16. Neptunium(V, VI) and plutonium(V, VI) interaction with malonate and phthalate ions in neutral aqueous solutions; crystalline compound formation

    International Nuclear Information System (INIS)

    Full text of publication follows: Carbonic acids are essential components of numerous natural liquids. Therefore, the study of their interaction with actinides is an important issue for general understanding of migration processes of transuranium elements in the environment. Here we present the results of our recent work on complexing reactions between AnO2n+ (An Np, Pu; n = 1, 2) and anions of malonic acid (CH2(COO)22- Lmlnt2-) and ortho-phthalic acid (C6H4(COO)22- = Lphthl2-). Np(VI) and Pu(VI) reduction by these organics has also been in the focus of the study. Based on the obtained data on the stability of solutions and on complex formation data in neutral media, the conditions of solid phase isolation have been determined. The crystal compound PuO2Lmlnt.3H2O was prepared and found to be isostructural to the known UO2Lmlnt.3H2O. It was impossible to isolate the NpO22+ analogue due to its rapid reduction to pentavalent state by malonate ions. Under the same conditions, the PuO22+ reduction rate was found to be several times lower. Novel plutonium(V) compounds MPuO2Lmlnt.nH2O (M = Na, NH4 and Cs) have been synthesized. It has been shown that the mono-phthalate complex compounds of Np(VI) and Pu(VI) can be isolated - AnO2Lphthl.2H2O and AnO2Lphthl.1.33H2O (the latter from hot solution). Neptunium and plutonium di-hydrates have different structures: NpO2Lphthl.2H2O crystallizes in triclinic and PuO2Lphthl.2H2O in monoclinic modification. The AnO2Lphthl.1.33H2O compounds were found to be isostructural. Hydrogen peroxide addition to a neutral plutonyl(VI) phthalate solution stabilizes plutonium in pentavalent oxidation state. Plutonium(V) bi-phthalate complex can be precipitated as [Co(NH3)6][PuO2Lphthl2].2H2O isostructural with its Np analogue. All novel crystalline solids have been characterized by XRD, TG/DTA methods, IR and UV-Vis absorption spectroscopy. (authors)

  17. Photon statistical properties of the cavity field in the two-atom Jaynes-Cummings model

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The model that two two-level atoms interact with a singel-mode cavity is studied. The exact solution of the time evolution operator for the two-atom Jaynes-Cummings model is presented by the bare-states approach. Furthermore, we investigate the dynamical properties of the photon statistics of the cavity field, and obtain a number of novel features.

  18. Motion control of a rotor with a cavity with a viscous fluid

    NARCIS (Netherlands)

    Gurchenkov, A. A.; Esenkov, A. S.; Tsurkov, V. I.

    2007-01-01

    A formulation and solution procedure of optimal control problems for perturbed relative uniform motion of a body with a cavity filled with a viscous incompressible fluid are proposed. In this paper, the case with a cylinder is considered; however, this approach is basically true for the a cavity of

  19. Frequency-feedback cavity enhanced spectrometer

    Science.gov (United States)

    Hovde, David Christian; Gomez, Anthony

    2015-08-18

    A spectrometer comprising an optical cavity, a light source capable of producing light at one or more wavelengths transmitted by the cavity and with the light directed at the cavity, a detector and optics positioned to collect light transmitted by the cavity, feedback electronics causing oscillation of amplitude of the optical signal on the detector at a frequency that depends on cavity losses, and a sensor measuring the oscillation frequency to determine the cavity losses.

  20. Computed tomography of the normal feline nasal cavity and paranasal sinuses

    International Nuclear Information System (INIS)

    Computed tomography (CT) images of the feline nasal cavity and paranasal sinuses were acquired from normal adult cats, Good resolution and anatomic detail were obtained from the CT images using soft tissue formatting. A description of normal feline nasal cavity and paranasal sinus anatomy using CT is presented

  1. Plasmonic-cavity model for radiating nano-rod antennas

    DEFF Research Database (Denmark)

    Peng, Liang; Mortensen, N. Asger

    2014-01-01

    In this paper, we propose the analytical solution of nano-rod antennas utilizing a cylindrical harmonics expansion. By treating the metallic nano-rods as plasmonic cavities, we derive closed-form expressions for both the internal and the radiated fields, as well as the resonant condition and the...

  2. Conductance Studies on Complex Formation between c-Methylcalix[4]resorcinarene and Titanium (III in Acetonitrile-H2O Binary Solutions

    Directory of Open Access Journals (Sweden)

    Naghmeh Saadati

    2013-09-01

    Full Text Available Calixresorcinarenes have proved to be unique molecules for molecular recognition via hydrogen bonding, hydrophobic and ionic interactions with suitable substrates such as cations. The study of the interactions involved in the complexation of different cations with calixresorcinarenes in solvent mixtures is important for a better understanding of the mechanism of biological transport, molecular recognition, and other analytical applications. This article summarizes different aspects of the complexes of the Ti3+ metal cation with c-methylcalix[4]resorcinarene (CMCR as studied by conductometry in acetonitrile (AN–water (H2O binary mixtures at different temperatures. Conductance data show that the metal cation/ligand (ML stoichiometry of the complexes in solution is 1:1 in all cases. Non-linear behaviour was observed for the variation of logKf of the complexes vs. the composition of the binary solvent mixtures. Selectivity of CMCR for the Ti3+ cation is sensitive to solvent composition; in some cases and at certain compositions of the mixed solvent systems, the selectivity order is changed. Values of thermodynamic parameters (, for formation of the CMCR–Ti3+ complexes in AN–H2O binary systems were obtained from the temperature dependence of stability constants, and the results show that the thermodynamics of complexation reactions are affected by the nature and composition of the mixed solvents.

  3. Dynamic studies of H-Ras•GTPγS interactions with nucleotide exchange factor Sos reveal a transient ternary complex formation in solution.

    Science.gov (United States)

    Vo, Uybach; Vajpai, Navratna; Embrey, Kevin J; Golovanov, Alexander P

    2016-01-01

    The cycling between GDP- and GTP- bound forms of the Ras protein is partly regulated by the binding of Sos. The structural/dynamic behavior of the complex formed between activated Sos and Ras at the point of the functional cycle where the nucleotide exchange is completed has not been described to date. Here we show that solution NMR spectra of H-Ras∙GTPγS mixed with a functional fragment of Sos (Sos(Cat)) at a 2:1 ratio are consistent with the formation of a rather dynamic assembly. H-Ras∙GTPγS binding was in fast exchange on the NMR timescale and retained a significant degree of molecular tumbling independent of Sos(Cat), while Sos(Cat) also tumbled largely independently of H-Ras. Estimates of apparent molecular weight from both NMR data and SEC-MALS revealed that, at most, only one H-Ras∙GTPγS molecule appears stably bound to Sos. The weak transient interaction between Sos and the second H-Ras∙GTPγS may provide a necessary mechanism for complex dissociation upon the completion of the native GDP → GTP exchange reaction, but also explains measurable GTP → GTP exchange activity of Sos routinely observed in in vitro assays that use fluorescently-labelled analogs of GTP. Overall, the data presents the first dynamic snapshot of Ras functional cycle as controlled by Sos. PMID:27412770

  4. Formation of size and shape tunable gold nanoparticles in solution by bio-assisted synthesis with bovine serum albumin in native and denaturated state

    International Nuclear Information System (INIS)

    Highlights: → We investigate the ability of bovine serum albumin to synthesize gold nanoparticles. → Bovine serum albumin protein acts as both reducing and stabilizing agent. → The size of nanoparticles can be varied by adjusting the protein concentration. → The shape of nanoparticles can be tuned by reaction temperature. → The obtained nanoparticles can be used as bio-substrates for SERS applications. - Abstract: We have successfully controlled the size and shape of gold nanoparticles (GNPs) through a one-step bio-assisted procedure by using bovine serum albumin (BSA) protein as both reducing and stabilizing agent. We found that the growing process of GNPs can be directly manipulated by simply controlling the BSA concentration in solution and the reaction temperature. The GNPs formation was followed both experimentally by UV-vis-NIR spectroscopy and transmission electron microscopy (TEM) and theoretically by finite difference time domain (FDTD) simulations. The surface plasmon resonance of as-prepared GNPs suits the needs of many biological applications.

  5. Cavity beam position monitors

    International Nuclear Information System (INIS)

    Beam-based alignment and feedback systems are essential for the operation of future linear colliders and free electron lasers. A certain number of beam position monitors with a resolution in the submicron range are needed at selected locations. Most beam position monitors detect the electric or the magnetic field excited by a beam of charged particles at different locations around the beam pipe. In resonant monitors, however, the excitation of special field configurations by an off-center beam is detected. These structures offer a large signal per micron displacement. This paper is an attempt to summarize the fundamental characteristics of resonant monitors, their advantages and shortcomings. Emphasis will be on the design of cylindrical cavities, in particular on the estimation of expected signals, of resolution limits and the resulting beam distortion. This includes also a short introduction into numerical methods. Fabrication, tuning, and other practical problems will be reviewed briefly. Finally, some resonant devices used for beam position diagnostics will be discussed and listed

  6. Differential diagnosis of pelvic cavities containing gas and fluids

    International Nuclear Information System (INIS)

    Since untreated intra-abdominal abscesses are associated with a high mortality rate, early diagnosis is important. In abscesses involving gas formation, plain radiographs of the abdomen in various projections are sufficient for diagnosis. In this article, differential diagnosis of cavities containing gas and fluids is discussed. (orig.)

  7. Internally Pressurized Spherical and Cylindrical Cavities in Rock Salt

    DEFF Research Database (Denmark)

    Krenk, Steen

    1978-01-01

    -linear zone and the volume reduction. Results are given for cavities in rock salt, and a comparison with measured stress concentrations is used to support the assumption of a hydrostatic stress state in undisturbed salt formations. Finally a method to estimate convergence due to creep is outlined....

  8. Three-dimensional cavity calculations

    International Nuclear Information System (INIS)

    The existence of a code that solves for the resonant electromagnetic modes of oscillation in arbitrarily-shaped three-dimensional cavities opens new possibilities in rf-structure analysis and research. The URMEL-3D code, the product of a multi-year collaboration between DESY, KFA-Juelich, and Los Alamos, has been used in some exploratory studies to determine the feasibility of using a 3-D code to calculate the properties of several practical rf structures. The results are reported here for three cases: the jungle gym, two coupled cavities, and a waveguide-cavity coupling problem

  9. Beam - cavity interaction beam loading

    International Nuclear Information System (INIS)

    The interaction of a beam with a cavity and a generator in cyclic accelerators or storage rings is investigated. Application of Maxwell's equations together with the nonuniform boundary condition allows one to get an equivalent circuit for a beam-loaded cavity. The general equation for beam loading is obtained on the basis of the equivalent circuit, and the beam admittance is calculated. Formulas for power consumption by a beam-loaded cavity are derived, and the optimal tuning and coupling factor are analyzed. (author)

  10. Fluid flow in cavity solved by finite element method

    OpenAIRE

    Burda, P.; Novotný, J.; Šístek, J. (Jakub)

    2010-01-01

    The problem of singularities caused by boundary conditions is studied in the flow of lid driven cavity. The asymptotic behaviour near the singularity points is used together with the apriori error estimates of the finite element solution, in order to design the finite element mesh adjusted to singularity. A posteriori error estimates are used as the principal tool for error analysis. Thus we obtain very precise solution in the vicinity of the singularity. Numerical results are presented.

  11. Transferring a cavity field entangled state in cavity QED

    Energy Technology Data Exchange (ETDEWEB)

    Ye Liu [Anhui Key Laboratory of Information Material and Devices, School of Physics and Material Science, Anhui University, Hefei 230039 (China); Guo Guangcan [Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026 (China)

    2005-08-01

    We propose a scheme for transferring an entanglement of zero- and one-photon states from one cavity to another. The scheme, which has 100% success probability, is mainly based on a two-mode cavity dispersively interacting with a three-level atom in the {lambda} configuration and does not involve Bell-state measurement. This scheme can also be used to teleport an unknown atomic state.

  12. Cavity-coupled molecular vibrational spectra and dynamics

    Science.gov (United States)

    Owrutsky, Jeffrey; Dunkelberger, Adam; Long, James; Fears, Kenan; Dressick, Walter; Compton, Ryan; Spann, Bryan; Simpkins, Blake

    Coherent coupling between an optical transition and confined optical mode, when sufficiently strong, gives rise to new modes separated by the vacuum Rabi splitting. Such systems have been investigated for electronic-state transitions, for quantum wells and dots, however, only very recently have vibrational transitions been explored. Both static and dynamic results are described for vibrational bands strongly coupled to optical cavities. First, we experimentally and numerically describe coupling between a Fabry-Perot cavity and carbonyl stretch (~1730 cm1) in poly-methylmethacrylate as a function of several parameters of the system including absorber strength and concentration as well as cavity length. Similar studies are carried out for anions both in solution and exchanged into cationic polymers. Ultrafast pump-probe studies are performed on W(CO)6 in solution which reveals changes to the transient spectra and modified relaxation rates. We believe these modified relaxation rates are a consequence of the energy separation between the vibration-cavity polariton modes and excited state transitions. Cavity-modified vibrational states and energy transfer may provide a new avenue for systematic control of molecular processes and chemistry. The work supported by the Office of Naval Research through the Naval Research Laboratory.

  13. Niobium LEP 2 accelerating cavities

    CERN Multimedia

    An accelerating cavity from LEP. This could be cut open to show the layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities were used in an upgrade of the LEP accelerator to double the energy of the particle beams.

  14. Geometry-Invariant Resonant Cavities

    CERN Document Server

    Liberal, Iñigo; Engheta, Nader

    2015-01-01

    Resonant cavities are one of the basic building blocks in various disciplines of science and technology, with numerous applications ranging from abstract theoretical modeling to everyday life devices. The eigenfrequencies of conventional cavities are a function of its geometry, and, thus, the size and shape of a resonant cavity is selected in order to operate at a specific frequency. Here, we demonstrate theoretically the existence of geometry-invariant resonant cavities, i.e., resonators whose eigenfrequency is invariant with respect to geometrical deformations. This effect is obtained by exploiting the unusual properties of zero-index metamaterials, which enable decoupling of the time and spatial field variations. This new class of resonators may inspire alternative design concepts, and it might lead to the first generation of deformable resonant devices.

  15. CRAB Cavity in CERN SPS

    International Nuclear Information System (INIS)

    Beam collisions with a crossing angle at the interaction point are often necessary in colliders to reduce the effects of parasitic collisions which induce emittance growth and decrease beam lifetime. The crossing angle reduces the geometrical overlap of the beams and hence the luminosity. Crab cavity offer a promising way to compensate the crossing angle and to realize effective head-on collisions. Moreover, the crab crossing mitigates the synchro-betatron resonances due to the crossing angle. A crab cavity experiment in SPS is proposed as a proof of principle before deciding on a full crab-cavity implementation in the LHC. In this paper, we investigate the effects of a single crab cavity on beam dynamics in the SPS and life time.

  16. Standard enthalpies of formation for L-tyrosine, DL-norleucine, DL-tryptophan, DL-α-alanyl-DL-norleucine, and products of their dissociation in an aqueous solution

    Science.gov (United States)

    Kochergina, L. A.; Krutova, O. N.; Damrina, K. V.

    2015-05-01

    Enthalpies of dissolution are determined for a series of crystal amino acids (L-tyrosine, DL-norleucine, and DL-tryptophan) and a DL-α-alanyl-DL-norleucine dipeptide in aqueous solutions of KOH at 298.15 K by means of direct calorimetry. Standard enthalpies of formation are determined for bioligands and products of their dissociation.

  17. LEP Radio Frequency Copper Cavities

    CERN Multimedia

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  18. Single and Coupled Nanobeam Cavities

    DEFF Research Database (Denmark)

    Ivinskaya, Aliaksandra; Lavrinenko, Andrei; Shyroki, Dzmitry M.; A. Sukhorukov, Andrey

    This book collects chapters on different theoretical and experimental aspects of photonics crystals for Nanophotonics applications. It is divided in two parts - a theoretical section and an experimental and applicative section. The first part includes chapters developing several numerical methods...... for analysis and design of photonic crystal devices, such as 2D ring resonators for filters, single and coupled nanobeam cavities, birefringence in photonic crystal cavities, threshold analysis in photonic crystal lasers, gap solitons in photonic crystals, novel photonic atolls, dynamic...

  19. RRR Characteristics for SRF Cavities

    OpenAIRE

    Jung, Yoochul; Hyun, Myungook; Joung, Mijoung

    2015-01-01

    The first heavy ion accelerator is being constructed by the rare isotope science project (RISP) launched by the Institute of Basic Science (IBS) in South Korea. Four different types of superconducting cavities were designed, and prototypes were fabricated such as a quarter wave resonator (QWR), a half wave resonator (HWR) and a single spoke resonator (SSR). One of the critical factors determining performances of the superconducting cavities is a residual resistance ratio (RRR). The RRR values...

  20. Apparatus for sealing access holes to cavities within the earth with rock glass

    International Nuclear Information System (INIS)

    An apparatus is described for sealing access holes to cavities within the earth which may be used for the disposal of radioactive waste. The method provides a fused seal integral with the rock formation. (U.K.)