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Sample records for solution temperature lcst

  1. Lower critical solution temperature (LCST) phase separation of glycol ethers for forward osmotic control.

    Science.gov (United States)

    Nakayama, Daichi; Mok, Yeongbong; Noh, Minwoo; Park, Jeongseon; Kang, Sunyoung; Lee, Yan

    2014-03-21

    Lower critical solution temperature (LCST) phase transition of glycol ether (GE)-water mixtures induces an abrupt change in osmotic pressure driven by a mild temperature change. The temperature-controlled osmotic change was applied for the forward osmosis (FO) desalination. Among three GEs evaluated, di(ethylene glycol) n-hexyl ether (DEH) was selected as a potential FO draw solute. A DEH-water mixture with a high osmotic pressure could draw fresh water from a high-salt feed solution such as seawater through a semipermeable membrane at around 10 °C. The water-drawn DEH-water mixture was phase-separated into a water-rich phase and a DEH-rich phase at around 30 °C. The water-rich phase with a much reduced osmotic pressure released water into a low-salt solution, and the DEH-rich phase was recovered into the initial DEH-water mixture. The phase separation behaviour, the residual GE concentration in the water-rich phase, the osmotic pressure of the DEH-water mixture, and the osmotic flux between the DEH-water mixture and salt solutions were carefully analysed for FO desalination. The liquid-liquid phase separation of the GE-water mixture driven by the mild temperature change between 10 °C and 30 °C is very attractive for the development of an ideal draw solute for future practical FO desalination.

  2. Simulation Studies of LCST-like Phase Transitions in Elastin-like Polypeptides (ELPs) and Conjugates of ELP with Rigid Macromolecules

    Science.gov (United States)

    Condon, Joshua; Martin, Tyler; Jayaraman, Arthi

    We use atomistic (AA) and coarse-grained (CG) molecular dynamics simulations to elucidate the thermodynamic driving forces governing lower critical solution temperature (LCST)-like phase transition exhibited by elastin-like peptides (ELPs) and conjugates of ELP with other macromolecules. In the AA simulations, we study ELP oligomers in explicit water, and mark the transition as the temperature at which they undergo a change in ``hydration'' state. While AA simulations are restricted to small systems of short ELPs and do not capture the chain aggregation observed in experiments of ELPs, they guide the phenomenological CG model development by highlighting the solvent induced polymer-polymer effective interactions with changing temperature. In the CG simulations, we capture the LCST polymer aggregation by increasing polymer-polymer effective attractive interactions in an implicit solvent. We examine the impact of conjugating a block of LCST polymer to another rigid unresponsive macromolecular block on the LCST-like transition. We find that when multiple LCST polymers are conjugated to a rigid polymer block, increased crowding of the LCST polymers shifts the onset of chain aggregation to smaller effective polymer-polymer attraction compared to the free LCST polymers. These simulation results provide guidance on the design of conjugated bio-mimetic thermoresponsive materials, and shape the fundamental understanding of the impact of polymer crowding on phase behavior in thermoresponsive LCST polymer systems.

  3. Urea decreases specific ion effects on the LCST of PMMA-block-PDMAEMA aggregates

    Directory of Open Access Journals (Sweden)

    João Carlos Perbone de Souza

    2014-12-01

    Full Text Available Urea is a well-known additive used as a mild protein denaturant. The effect of urea on proteins, micellar systems and other colloids is still under debate. In particular, urea has shown interesting effects on the ion binding in systems like charged micelles, vesicles or Langmuir-Blodgett films. The urea effect on polymeric aggregates in water is still an open field. For instance, the additive may affect properties such as cmc, LCST, UCST and others. In particular, LCST is a property that can be very convenient for designing smart systems that respond to temperature. Previous studies have indicated that the LCST of positive charged copolymers aggregates based on poly[N-dimethyl(ethylamine methacrylate], PDMAEMA, can be nicely modulated by anions in aqueous solution and such phenomenon depends on the nature of the anion present. In this work, it has been demonstrated that urea also affects the LCST of PMMA-block-PDMAEMA aggregates in aqueous solution. In addition, in the presence of high concentrations of the additive, the specific behavior of the anions is lost, supporting the general mechanism of urea reducing the differences on ion binding to surfaces in aqueous solutions. To the best of our knowledge, this is the first time those phenomena are shown in polymer micelles.

  4. Thermodynamic description of Hofmeister effects on the LCST of thermosensitive polymers.

    Science.gov (United States)

    Heyda, Jan; Dzubiella, Joachim

    2014-09-18

    Cosolvent effects on protein or polymer collapse transitions are typically discussed in terms of a two-state free energy change that is strictly linear in cosolute concentration. Here we investigate in detail the nonlinear thermodynamic changes of the collapse transition occurring at the lower critical solution temperature (LCST) of the role-model polymer poly(N-isopropylacrylamide) [PNIPAM] induced by Hofmeister salts. First, we establish an equation, based on the second-order expansion of the two-state free energy in concentration and temperature space, which excellently fits the experimental LCST curves and enables us to directly extract the corresponding thermodynamic parameters. Linear free energy changes, grounded on generic excluded-volume mechanisms, are indeed found for strongly hydrated kosmotropes. In contrast, for weakly hydrated chaotropes, we find significant nonlinear changes related to higher order thermodynamic derivatives of the preferential interaction parameter between salts and polymer. The observed non-monotonic behavior of the LCST can then be understood from a not yet recognized sign change of the preferential interaction parameter with salt concentration. Finally, we find that solute partitioning models can possibly predict the linear free energy changes for the kosmotropes, but fail for chaotropes. Our findings cast strong doubt on their general applicability to protein unfolding transitions induced by chaotropes.

  5. Recognition-Mediated Hydrogel Swelling Controlled by Interaction with a Negative Thermoresponsive LCST Polymer.

    Science.gov (United States)

    Belal, Khaled; Stoffelbach, François; Lyskawa, Joël; Fumagalli, Matthieu; Hourdet, Dominique; Marcellan, Alba; Smet, Lieselot De; de la Rosa, Victor R; Cooke, Graeme; Hoogenboom, Richard; Woisel, Patrice

    2016-11-02

    Most polymeric thermoresponsive hydrogels contract upon heating beyond the lower critical solution temperature (LCST) of the polymers used. Herein, we report a supramolecular hydrogel system that shows the opposite temperature dependence. When the non-thermosesponsive hydrogel NaphtGel, containing dialkoxynaphthalene guest molecules, becomes complexed with the tetra cationic macrocyclic host CBPQT 4+ , swelling occurred as a result of host-guest complex formation leading to charge repulsion between the host units, as well as an osmotic contribution of chloride counter-ions embedded in the network. The immersion of NaphtGel in a solution of poly(N-isopropylacrylamide) with tetrathiafulvalene (TTF) end groups complexed with CBPQT 4+ induced positive thermoresponsive behaviour. The LCST-induced dethreading of the polymer-based pseudorotaxane upon heating led to transfer of the CBPQT 4+ host and a concomitant swelling of NaphtGel. Subsequent cooling led to reformation of the TTF-based host-guest complexes in solution and contraction of the hydrogel. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  6. Effects of Hofmeister Anions on the LCST of PNIPAM as a Function of Molecular Weight

    Science.gov (United States)

    Zhang, Yanjie; Furyk, Steven; Sagle, Laura B.; Cho, Younhee; Bergbreiter, David E.; Cremer, Paul S.

    2008-01-01

    The effect of a series of sodium salts on the lower critical solution temperature (LCST) of poly(N-isopropylacrylamide), PNIPAM, was investigated as a function of molecular weight and polymer concentration with a temperature gradient microfluidic device under a dark-field microscope. In solutions containing sufficient concentrations of kosmotropic anions, the phase transition of PNIPAM was resolved into two separate steps for higher molecular weight samples. The first step of this two step transition was found to be sensitive to the polymer’s molecular weight and solution concentration, while the second step was not. Moreover, the binding of chaotropic anions to the polymer was also influenced by molecular weight. Both sets of results could be explained by the formation of intramolecular and intermolecular hydrogen-bonding between polymer chains. By contrast, the hydrophobic hydration of the isopropyl moieties and polymer backbone was found to be unaffected by either the polymer’s molecular weight or solution concentration. PMID:18820735

  7. Tough Al-alginate/poly(N-isopropylacrylamide) hydrogel with tunable LCST for soft robotics.

    Science.gov (United States)

    Zheng, Wen Jiang; An, Ning; Yang, Jian Hai; Zhou, Jinxiong; Chen, Yong Mei

    2015-01-28

    Tough Al-alginate/poly(N-isopropylacrylamide) (PNIPAM) hydrogel has been synthesized by introducing an interpenetrating network with hybrid physically cross-linked alginate and chemically cross-linked PNIPAM. Varying the concentration of AlCl3 regulates the mechanical properties of the tough hydrogel and tunes its lower critical solution temperature (LCST) as well. The tough Al-alginate/PNIPAM exhibits 6.3 ± 0.3 MPa of compressive stress and 9.95 of uniaxial stretch. Tunability of LCST is also achieved in a wide range within 22.5-32 °C. A bending beam actuator and a four-arm gripper made of bilayer (Na-alginate/PNIPAM)/(Al-alginate/PNIPAM) hydrogel as prototype of all-hydrogel soft robotics are demonstrated. A finite element (FE) simulation model is developed to simulate the deformation of the soft robotics. The FE simulation not only reproduces the deformation process of performed experiments but also predicts more complicated devices that can be explored in the future. This work broadens the application of temperature-responsive PNIPAM-based hydrogels.

  8. Influence of cyclodextrin on the UCST- and LCST-behavior of poly(2-methacrylamido-caprolactam-co-(N,N-dimethylacrylamide

    Directory of Open Access Journals (Sweden)

    Alexander Burkhart

    2014-08-01

    Full Text Available The monomer 2-methacrylamido-caprolactam (4 was synthesized from methacryloyl chloride (3 and racemic α-amino-ε-caprolactam (2. Copolymerization of 4 with N,N-dimethylacrylamide (5 was carried out by a free-radical mechanism using 2,2’-azobis(2-methylpropionitrile (AIBN as an initiator. The new copolymers show a lower critical solution temperature (LCST in water and an upper critical solution temperature (UCST in ethanol, 1-propanol, and 1-butanol. The solubility properties of the copolymers can be influenced significantly by the addition of randomly methylated β-cyclodextrin (CD. The complexation of the copolymers with CD, was confirmed by the use of ROESY-NMR-spectroscopy.

  9. Sequence Directionality Dramatically Affects LCST Behavior of Elastin-Like Polypeptides.

    Science.gov (United States)

    Li, Nan K; Roberts, Stefan; Quiroz, Felipe Garcia; Chilkoti, Ashutosh; Yingling, Yaroslava G

    2018-04-30

    Elastin-like polypeptides (ELP) exhibit an inverse temperature transition or lower critical solution temperature (LCST) transition phase behavior in aqueous solutions. In this paper, the thermal responsive properties of the canonical ELP, poly(VPGVG), and its reverse sequence poly(VGPVG) were investigated by turbidity measurements of the cloud point behavior, circular dichroism (CD) measurements, and all-atom molecular dynamics (MD) simulations to gain a molecular understanding of mechanism that controls hysteretic phase behavior. It was shown experimentally that both poly(VPGVG) and poly(VGPVG) undergo a transition from soluble to insoluble in aqueous solution upon heating above the transition temperature ( T t ). However, poly(VPGVG) resolubilizes upon cooling below its T t , whereas the reverse sequence, poly(VGPVG), remains aggregated despite significant undercooling below the T t . The results from MD simulations indicated that a change in sequence order results in significant differences in the dynamics of the specific residues, especially valines, which lead to extensive changes in the conformations of VPGVG and VGPVG pentamers and, consequently, dissimilar propensities for secondary structure formation and overall structure of polypeptides. These changes affected the relative hydrophilicities of polypeptides above T t , where poly(VGPVG) is more hydrophilic than poly(VPGVG) with more extended conformation and larger surface area, which led to formation of strong interchain hydrogen bonds responsible for stabilization of the aggregated phase and the observed thermal hysteresis for poly(VGPVG).

  10. Bio-inspired intelligent evaporation modulation in a thermo-sensitive nanogel colloid solution for self-thermoregulation.

    Science.gov (United States)

    Huang, Zhi; Liu, Kang; Feng, Yanhui; Zhou, Jun; Zhang, Xinxin

    2017-06-28

    Intelligent evaporation and temperature modulation plays an important role in self-regulation of living organisms and many industrial applications. Here we demonstrate that a poly(N-isopropylacrylamide) (PNIPAM) nanogel colloid solution can spontaneously and intelligently modulate its evaporation rate with temperature variation, which has a larger evaporation rate than distilled water at a temperature higher than its lower critical solution temperature (LCST) and a smaller evaporation rate at a temperature lower than its LCST. It performs just like human skin. Theoretical analysis based on the thermodynamic derivation reveals that the evaporation rate transition around the LCST may originate from the saturated vapor pressure transition caused by the status transformation of the PNIPAM additives. An intelligent thermoregulation system based on the PNIPAM colloid solution is also demonstrated, illustrating its potential for intelligent temperature control and acting as an artificial skin.

  11. Role of Side-Chain Molecular Features in Tuning Lower Critical Solution Temperatures (LCSTs) of Oligoethylene Glycol Modified Polypeptides.

    Science.gov (United States)

    Gharakhanian, Eric G; Deming, Timothy J

    2016-07-07

    A series of thermoresponsive polypeptides has been synthesized using a methodology that allowed facile adjustment of side-chain functional groups. The lower critical solution temperature (LCST) properties of these polymers in water were then evaluated relative to systematic molecular modifications in their side-chains. It was found that in addition to the number of ethylene glycol repeats in the side-chains, terminal and linker groups also have substantial and predictable effects on cloud point temperatures (Tcp). In particular, we found that the structure of these polypeptides allowed for inclusion of polar hydroxyl groups, which significantly increased their hydrophilicity and decreased the need to use long oligoethylene glycol repeats to obtain LCSTs. The thioether linkages in these polypeptides were found to provide an additional structural feature for reversible switching of both polypeptide conformation and thermoresponsive properties.

  12. Lower critical solution temperature behavior of alpha-substituted poly(acrylic acids)s, cyclopolymerization of N-vinylformamido-methylacrylates, and use of the World-Wide Web in polymer science education

    Science.gov (United States)

    Michalovic, Mark Stephen

    A series of alpha-substituted poly(acrylic acid)s was synthesized and characterized. Their aqueous solution properties were investigated with respect to lower critical solution temperature (LCST) behavior. Poly(alpha-methoxymethylacrylic acid) was found to have a lower critical solution temperature (LCST) of 46°C, poly(alpha-methoxyethoxymethylacrylic acid) showed an LCST of 26.5°C and poly(alpha-methoxyethoxyethoxymethylacrylic acid) showed an LCST of 66°C. The cloud points of the solutions of these polymers were found to be sensitive to pH, and to concentrations of additives such as urea, salts, and surfactants. Because of low molecular weight due to chain transfer, high molecular weight analogs of the ether-linked polymers were synthesized in which ester linkages joined the oligo-oxyethylene segment to the acrylate moiety. Poly(alpha-methoxyethoxyacetoxymethylacrylic acid) was the only one of this series to give an LCST with a value of 52.5°C. Copolymers of t-butyl alpha-methoxymethylacrylate (tBMMA) with alpha-(1H,1H- perfluorooctyloxymethyl)acrylic acid (PFOMA) were synthesized, deprotected and their lower critical solution temperatures (LCSTs) evaluated. At PFOMA feed ratios of 0.25 mol % or less, no observable change in the LCST was observed, while at PFOMA feed ratios of above 0.25 mol % to 1.125 mol %, a large linear decrease in the LCST was observed with increasing fluorocarbon content. t-Butyl alpha-(N-vinylformamidomethyl)acrylate (tBVFA) and ethyl alpha-(N-vinylformamidomethyl)acrylate (EVFA) were synthesized from t-butyl alpha-bromomethylacrylate and ethyl alpha-chloromethylacrylate, respectively. tBVFA was found to cyclopolymerize at 120°C in DMF, DMSO, and 1,2-dichlorobenzene at solvent:monomer ratios of 10:1 vol:wt. Molecular weights for poly(tBVFA) ranged from 10,000 to 13,000 as estimated by size-exclusion chromatography. At lower solvent monomer ratio (1:1), and at lower temperature (71°C), crosslinking occurred. EVFA was found to

  13. Comb-like temperature-responsive polyhydroxyalkanoate-graft-poly(2-dimethylamino-ethylmethacrylate) for controllable protein adsorption

    DEFF Research Database (Denmark)

    Yao, Hui; Wei, Daixu; Che, Xuemei

    2016-01-01

    %. Graft copolymer PHA-g-PDMAEMA showed enhanced thermal stability, biocompatibility and controllable hydrophilicity compared with non-grafted P(3HDD-co-3H9D). The grafted material presented an obvious tendency of increasing protein adsorptions over the lower critical solution temperature (LCST 47.5 °C...... controllable protein adsorption for biomedical usages....

  14. Perylene bisimide hydrogels and lyotropic liquid crystals with temperature-responsive color change† †Electronic supplementary information (ESI) available: Detailed procedures and results for all reported experiments, along with synthetic details for PBI 1. See DOI: 10.1039/c6sc02249a Click here for additional data file.

    Science.gov (United States)

    Görl, Daniel; Soberats, Bartolome; Herbst, Stefanie; Stepanenko, Vladimir

    2016-01-01

    The self-assembly of perylene bisimide (PBI) dyes bearing oligo ethylene glycol (OEG) units in water affords responsive functional nanostructures characterized by their lower critical solution temperature (LCST). Tuning of the LCST is realized by a supramolecular approach that relies on two structurally closely related PBI–OEG molecules. The two PBIs socially co-assemble in water and the resulting nanostructures exhibit a single LCST in between the transition temperatures of the aggregates formed by single components. This permits to precisely tune the transition from a hydrogel to a lyotropic liquid crystal state at temperatures between 26 and 51 °C by adjusting the molar fraction of the two PBIs. Owing to concomitant changes in PBI–PBI interactions this phase transition affords a pronounced color change with “fluorescence-on” response that can be utilized as a smart temperature sensory system. PMID:28451124

  15. Polymer Inverse Temperature-Dependent Solubility: A Visual Demonstration of the Importance of "T[Delta]S" in the Gibbs Equation

    Science.gov (United States)

    Bergbreiter, David E.; Mijalis, Alexander J.; Fu, Hui

    2012-01-01

    Reversible polymer dehydration and precipitation from water due to the unfavorable entropy of hydration is examined using a melting-point apparatus. The thermoresponsive lower critical solution temperature (LCST) behavior of poly(N-isopropylacrylamide) (PNIPAM) is responsible for these effects. An experiment is described that allows students to…

  16. Thermosensitive Triterpenoid-Appended Polymers with Broad Temperature Tunability Regulated by Host-Guest Chemistry.

    Science.gov (United States)

    Hao, Jie; Gao, Yuxia; Li, Ying; Yan, Qiang; Hu, Jun; Ju, Yong

    2017-09-05

    Thermoresponsive water-soluble polymers are of great importance since they typically show a lower critical solution temperature (LCST) in aqueous media. In this research, the LCST change in broad temperature ranges of copolymers composed of natural glycyrrhetinic acid (GA)-based methacrylate and N,N'-dimethylacrylamides (DMAs) was investigated as a function of the concentration and the content of GA pendants. By complexation of GA pendants with β-cyclodextrin (β-CD), a side-chain polypseudorotaxane was obtained, which exhibited a significant increase in the LCST of copolymers. Moreover, the precisely reversible control of the LCST behavior was realized through adding a competing guest molecule, sodium 1-admantylcarboxylate. This work illustrates a simple and effective approach to endow water-soluble polymers with broad temperature tunability and helps us further understand the effect of a biocompatible host-guest complementary β-CD/GA pair on the thermoresponsive process. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. The Krafft temperature of surfactant solutions

    OpenAIRE

    Manojlović Jelena Ž.

    2012-01-01

    Our main motivation to revisit the solution properties of cetyltrimethylammonium bromide is related to the clear requirement for better control of the adsorption parameters to form uniform self-assembled monolayers on muscovite mica substrates. To readily monitor the temporal evolution of structural details in cetyltrimethylammonium bromide solutions, we realized a rather simple conductivity experiment. Conductivity measurements were carried out as a function of temperature, to look clo...

  18. Crystal growth from low-temperature solutions

    International Nuclear Information System (INIS)

    Sangwal, K.

    1994-01-01

    The state of the art in crystal growth from solutions at low-temperatures has been done. The thermodynamic and kinetic parameters have been discussed in respect to different systems. The methods of crystal growth from water and organic solutions and different variants of their technical realizations have been reviewed. Also the growth by chemical reactions and gel growth have been described. The large number of examples have been shown. 21 refs, 30 figs, 3 tabs

  19. IPN hydrogels based on PNIPAAm and PVA-Ma networks: characterization through measure of LCST, swelling ratio and mechanical properties - doi: 10.4025/actascitechnol.v34i2.15019

    Directory of Open Access Journals (Sweden)

    Adriana Cristina Wenceslau

    2012-03-01

    Full Text Available IPN hydrogels based on chemically modified poly(vinyl alcohol (or PVA-Ma, with different degrees of substitution (DS, and poly(N-isopropylacrylamide (or PNIPAAm were obtained and characterized through measures of LCST, swelling ratio and mechanical properties. Linear PVA-Ma with several DS were obtained through the chemical reaction of PVA with glycidyl methacrylate (GMA. The DS of various PVA-Ma were determined through 1H NMR spectroscopy. Two steps were used for preparation the PVA-Ma/PNIPAAm membrane hydrogels. In the first step the PVA-Ma hydrogels (using PVA-Ma with different DS were prepared by reaction of double bonds on PVA-Ma, using the persulfate/TEMED system. Using a photoreaction pathway in the second step, PNIPAAm network was prepared within the parent PVA-Ma network at different PVA-Ma/NIPAAm ratios. The studies show that degree of swelling ratio (SR of PVA-Ma/PNIPAAm IPN hydrogels is dependent of temperature. The LCST for each IPN-hydrogel was determined by measuring the intensity of light transmitted through the hydrogel. The LCST of the IPN hydrogels ranged from 34.6 to 38.1oC. The elastic modules of swollen IPN hydrogels increased from 25 to 35oC but decreased by further warming to 45oC. The LCST, swelling ratio and mechanical properties of PVA-Ma/PNIPAAm IPN hydrogels can be tailored by tuning the PVA-Ma/NIPAAm ratio.

  20. Surface sulfonamide modification of poly(N-isopropylacrylamide)-based block copolymer micelles to alter pH and temperature responsive properties for controlled intracellular uptake.

    Science.gov (United States)

    Cyphert, Erika L; von Recum, Horst A; Yamato, Masayuki; Nakayama, Masamichi

    2018-06-01

    Two different surface sulfonamide-functionalized poly(N-isopropylacrylamide)-based polymeric micelles were designed as pH-/temperature-responsive vehicles. Both sulfadimethoxine- and sulfamethazine-surface functionalized micelles were characterized to determine physicochemical properties, hydrodynamic diameters, zeta potentials, temperature-dependent size changes, and lower critical solution temperatures (LCST) in both pH 7.4 and 6.8 solutions (simulating both physiological and mild low pH conditions), and tested in the incorporation of a proof-of-concept hydrophobic antiproliferative drug, paclitaxel. Cellular uptake studies were conducted using bovine carotid endothelial cells and fluorescently labeled micelles to evaluate if there was enhanced cellular uptake of the micelles in a low pH environment. Both variations of micelles showed enhanced intracellular uptake under mildly acidic (pH 6.8) conditions at temperatures slightly above their LCST and minimal uptake at physiological (pH 7.4) conditions. Due to the less negative zeta potential of the sulfamethazine-surface micelles compared to sulfadimethoxine-surface micelles, and the proximity of their LCST to physiological temperature (37°C), the sulfamethazine variation was deemed more amenable for clinically relevant temperature and pH-stimulated applications. Nevertheless, we believe both polymeric micelle variations have the capacity to be implemented as an intracellular drug or gene delivery system in response to mildly acidic conditions. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1552-1560, 2018. © 2018 Wiley Periodicals, Inc.

  1. Weak Solution and Weakly Uniformly Bounded Solution of Impulsive Heat Equations Containing “Maximum” Temperature

    Directory of Open Access Journals (Sweden)

    Oyelami, Benjamin Oyediran

    2013-09-01

    Full Text Available In this paper, criteria for the existence of weak solutions and uniformly weak bounded solution of impulsive heat equation containing maximum temperature are investigated and results obtained. An example is given for heat flow system with impulsive temperature using maximum temperature simulator and criteria for the uniformly weak bounded of solutions of the system are obtained.

  2. Solution hardening and strain hardening at elevated temperatures

    International Nuclear Information System (INIS)

    Kocks, U.F.

    1982-10-01

    Solutes can significantly increase the rate of strain hardening; as a consequence, the saturation stress, at which strain hardening tends to cease for a given temperature and strain rate, is increased more than the yield stress: this is the major effect of solutes on strength at elevated temperatures, especially in the regime where dynamic strain-aging occurs. It is shown that local solute mobility can affect both the rate of dynamic recovery and the dislocation/dislocation interaction strength. The latter effect leads to multiplicative solution strengthening. It is explained by a new model based on repeated dislocation unlocking, in a high-temperature limit, which also rationalizes the stress dependence of static and dynamic strain-aging, and may help explain the plateau of the yield stress at elevated temperatures. 15 figures

  3. Osmotic potential calculations of inorganic and organic aqueous solutions over wide solute concentration levels and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Cochrane, T. T., E-mail: agteca@hotmail.com [AGTECA S.A., 230 Oceanbeach Road, Mount Maunganui, Tauranga 3116 (New Zealand); Cochrane, T. A., E-mail: tom.cochrane@canterbury.ac.nz [Department of Civil and Natural Resources Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand)

    2016-01-15

    Purpose: To demonstrate that the authors’ new “aqueous solution vs pure water” equation to calculate osmotic potential may be used to calculate the osmotic potentials of inorganic and organic aqueous solutions over wide ranges of solute concentrations and temperatures. Currently, the osmotic potentials of solutions used for medical purposes are calculated from equations based on the thermodynamics of the gas laws which are only accurate at low temperature and solute concentration levels. Some solutions used in medicine may need their osmotic potentials calculated more accurately to take into account solute concentrations and temperatures. Methods: The authors experimented with their new equation for calculating the osmotic potentials of inorganic and organic aqueous solutions up to and beyond body temperatures by adjusting three of its factors; (a) the volume property of pure water, (b) the number of “free” water molecules per unit volume of solution, “N{sub f},” and (c) the “t” factor expressing the cooperative structural relaxation time of pure water at given temperatures. Adequate information on the volume property of pure water at different temperatures is available in the literature. However, as little information on the relative densities of inorganic and organic solutions, respectively, at varying temperatures needed to calculate N{sub f} was available, provisional equations were formulated to approximate values. Those values together with tentative t values for different temperatures chosen from values calculated by different workers were substituted into the authors’ equation to demonstrate how osmotic potentials could be estimated over temperatures up to and beyond bodily temperatures. Results: The provisional equations formulated to calculate N{sub f}, the number of free water molecules per unit volume of inorganic and organic solute solutions, respectively, over wide concentration ranges compared well with the calculations of N{sub f

  4. Osmotic potential calculations of inorganic and organic aqueous solutions over wide solute concentration levels and temperatures

    International Nuclear Information System (INIS)

    Cochrane, T. T.; Cochrane, T. A.

    2016-01-01

    Purpose: To demonstrate that the authors’ new “aqueous solution vs pure water” equation to calculate osmotic potential may be used to calculate the osmotic potentials of inorganic and organic aqueous solutions over wide ranges of solute concentrations and temperatures. Currently, the osmotic potentials of solutions used for medical purposes are calculated from equations based on the thermodynamics of the gas laws which are only accurate at low temperature and solute concentration levels. Some solutions used in medicine may need their osmotic potentials calculated more accurately to take into account solute concentrations and temperatures. Methods: The authors experimented with their new equation for calculating the osmotic potentials of inorganic and organic aqueous solutions up to and beyond body temperatures by adjusting three of its factors; (a) the volume property of pure water, (b) the number of “free” water molecules per unit volume of solution, “N f ,” and (c) the “t” factor expressing the cooperative structural relaxation time of pure water at given temperatures. Adequate information on the volume property of pure water at different temperatures is available in the literature. However, as little information on the relative densities of inorganic and organic solutions, respectively, at varying temperatures needed to calculate N f was available, provisional equations were formulated to approximate values. Those values together with tentative t values for different temperatures chosen from values calculated by different workers were substituted into the authors’ equation to demonstrate how osmotic potentials could be estimated over temperatures up to and beyond bodily temperatures. Results: The provisional equations formulated to calculate N f , the number of free water molecules per unit volume of inorganic and organic solute solutions, respectively, over wide concentration ranges compared well with the calculations of N f using recorded

  5. synthesis and characterisation of temperature responsive poly (2 ...

    African Journals Online (AJOL)

    DR. AMINU

    2010-06-01

    Jun 1, 2010 ... phase separation from solution while below LCST, the polymer is miscible in .... to remove impurities such as lutidinium salt that could interfere with the ... ppm was due to residual Acetonitrile that was used as polymerisation ...

  6. The effects of injected solution temperature on intravenous regional anaesthesia.

    Science.gov (United States)

    Paul, D L; Logan, M R; Wildsmith, J A

    1988-05-01

    Ten healthy volunteers received three standard Bier's blocks. Prilocaine 0.5%, 40 ml was injected at a solution temperature of 0 degrees C, 22 degrees C or 37 degrees C. Recordings were made of sensory block, motor block, intravenous pressure, limb temperature and pain on injection. There were no differences between the three treatments in the rate of development or in the quality of block but there was a significant difference in the comfort of injection. Cold solutions caused most, and warm solutions least discomfort.

  7. Effect of solvent and temperature on solution-crystallized terfenadine

    International Nuclear Information System (INIS)

    Leitao, M. Luisa P.; Canotilho, Joao; Ferreira, Simone C.R.; Sousa, Adriano T.; Simoes Redinha, J.

    2004-01-01

    The aim of this work was to understand the crystallization process of terfenadine in solution. Cooling of saturated solutions prepared at 50 deg. C at different temperatures, evaporating the solvent from nearly saturated solutions at a certain temperature, and exposing ethanol solutions of terfenadine to water vapour atmosphere were the techniques used for obtaining terfenadine specimens. The characterization of these specimens was carried out by thermal microscopy, differential thermal analysis, thermogravimetry and powder X-ray diffraction. Crystalline phases, amorphous solids, and solvates were identified. For the solvents used in the present study, the crystallinity degree of terfenadine decreases from ethanol-water to ethanol and from this to methanol. Decreasing the temperature promotes the formation of amorphous solid material; at low temperatures, methanol and ethanol solvates are also formed. Desolvation, following the terfenadine aggregation process in solution accounts for the different behaviour found for the solvents and for the effect of temperature on the structure. The role of the solvent as structure-mediator is explained on the grounds of the values previously published for the enthalpy of solution of terfenadine in the solvents under study

  8. Room temperature electrodeposition of actinides from ionic solutions

    Science.gov (United States)

    Hatchett, David W.; Czerwinski, Kenneth R.; Droessler, Janelle; Kinyanjui, John

    2017-04-25

    Uranic and transuranic metals and metal oxides are first dissolved in ozone compositions. The resulting solution in ozone can be further dissolved in ionic liquids to form a second solution. The metals in the second solution are then electrochemically deposited from the second solutions as room temperature ionic liquid (RTIL), tri-methyl-n-butyl ammonium n-bis(trifluoromethansulfonylimide) [Me.sub.3N.sup.nBu][TFSI] providing an alternative non-aqueous system for the extraction and reclamation of actinides from reprocessed fuel materials. Deposition of U metal is achieved using TFSI complexes of U(III) and U(IV) containing the anion common to the RTIL. TFSI complexes of uranium were produced to ensure solubility of the species in the ionic liquid. The methods provide a first measure of the thermodynamic properties of U metal deposition using Uranium complexes with different oxidation states from RTIL solution at room temperature.

  9. Hydration, phase separation and nonlinear rheology of temperature-sensitive water-soluble polymers

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Fumihiko; Koga, Tsuyoshi [Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510 (Japan); Kaneda, Isamu [Department of Food Science, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501 (Japan); Winnik, Francoise M, E-mail: ftanaka@phys.polym.kyoto-u.ac.jp [Department of Chemistry and Faculty of Pharmacy, University of Montreal, Montreal, H3C 3J7 (Canada)

    2011-07-20

    The collapse of a poly(N-isopropylacrylamide) (PNIPAM) chain upon heating and the phase diagrams of aqueous PNIPAM solutions with a very flat lower critical solution temperature (LCST) phase separation line are theoretically studied on the basis of cooperative dehydration (simultaneous dissociation of bound water molecules in a group of correlated sequence), and compared with the experimental observation of temperature-induced coil-globule transition by light scattering methods. The transition becomes sharper with the cooperativity parameter {sigma} of hydration. The reentrant coil-globule-coil transition and cononsolvency in a mixed solvent of water and methanol are also studied from the viewpoint of competitive hydrogen bonds between polymer-water and polymer-methanol. The downward shift of the cloud-point curves (LCST cononsolvency) with the mol fraction of methanol due to the competition is calculated and compared with the experimental data. Aqueous solutions of hydrophobically modified PNIPAM carrying short alkyl chains at both chain ends (telechelic PNIPAM) are theoretically and experimentally studied. The LCST of these solutions is found to shift downward along the sol-gel transition curve as a result of end-chain association (association-induced phase separation), and separate from the coil-globule transition line. Associated structures in the solution, such as flower micelles, mesoglobules, and higher fractal assembly, are studied by ultra small-angle neutron scattering with theoretical modeling of the scattering function. Dynamic-mechanical modulus, nonlinear stationary viscosity, and stress build-up in start-up shear flows of the associated networks are studied on the basis of the affine and non-affine transient network theory. The molecular conditions for thickening, strain hardening, and stress overshoot are found in terms of the nonlinear amplitude A of the chain tension and the tension-dissociation coupling constant g.

  10. Low temperature kinetics of In-Cd solid solution decomposition

    Czech Academy of Sciences Publication Activity Database

    Pal-Val, P.P.; Pal-Val, L.N.; Ostapovets, A.A.; Vaněk, Přemysl

    2008-01-01

    Roč. 137, - (2008), s. 35-42 ISSN 1012-0394 Institutional research plan: CEZ:AV0Z10100520 Keywords : low temperatures * In-based alloys * solid solutions * isothermal structure instability * Young's modulus * electrical resistivity * phase diagrams Subject RIV: BM - Solid Matter Physics ; Magnetism http://www.scientific.net/3-908451-53-1/35/

  11. Transitions in aqueous solutions of sucrose at subzero temperatures

    Czech Academy of Sciences Publication Activity Database

    Sikora, Antonín; Dupanov, V. O.; Kratochvíl, Jaroslav; Zámečník, J.

    2007-01-01

    Roč. 46, č. 1 (2007), s. 71-85 ISSN 0022-2348 R&D Projects: GA ČR(CZ) GA522/04/0384 Institutional research plan: CEZ:AV0Z40500505 Keywords : aqueous sucrose solutions * subzero temperature * glass transitions Subject RIV: BJ - Thermodynamics Impact factor: 0.809, year: 2007

  12. pH- and temperature-sensitive polymeric microspheres for drug delivery: the dissolution of copolymers modulates drug release.

    Science.gov (United States)

    Fundueanu, Gheorghe; Constantin, Marieta; Stanciu, Cristina; Theodoridis, Georgios; Ascenzi, Paolo

    2009-12-01

    Most pH-/temperature-responsive polymers for controlled release of drugs are used as cross-linked hydrogels. However, the solubility properties of the linear polymers below and above the lower critical solution temperature (LCST) are not exploited. Here, the preparation and characterization of poly (N-isopropylacrylamide-co-methacrylic acid-co-methyl methacrylate) (poly (NIPAAm-co-MA-co-MM)) and poly (N-isopropylacrylamide-co-acrylamide) (poly (NIPAAm-co-AAm)), known as "smart" polymers (SP), is reported. Both poly (NIPAAm-co-MA-co-MM) and poly (NIPAAm-co-AAm) display pH- and temperature-responsive properties. Poly (NIPAAm-co-MA-co-MM) was designed to be insoluble in the gastric fluid (pH = 1.2), but soluble in the intestinal fluid (pH = 6.8 and 7.4), at the body temperature (37 degrees C). Poly (NIPAAm-co-AAm) was designed to have a lower critical solution temperature (LCST) corresponding to 37 degrees C at pH = 7.4, therefore it is not soluble above the LCST. The solubility characteristics of these copolymers were exploited to modulate the rate of release of drugs by changing pH and/or temperature. These copolymers were solubilized with hydrophobic cellulose acetate butyrate (CAB) and vitamin B(12) (taken as a water soluble drug model system) in an acetone/methanol mixture and dispersed in mineral oil. By a progressive evaporation of the solvent, the liquid droplets were transformed into loaded CAB/SP microspheres. Differential scanning calorimetric studies and scanning electron microscopy analysis demonstrated that the polymeric components of the microspheres precipitated separately during solvent evaporation forming small microdomains. Moreover, vitamin B(12) was found to be molecularly dispersed in both microdomains with no specific affinity for any polymeric component of microspheres. The release of vitamin B(12) was investigated as a function of temperature, pH, and the CAB/SP ratio.

  13. Corrosion of silicon nitride in high temperature alkaline solutions

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Liyan, E-mail: liyan.qiu@cnl.ca; Guzonas, Dave A.; Qian, Jing

    2016-08-01

    The corrosion of silicon nitride (Si{sub 3}N{sub 4}) in alkaline solutions was studied at temperatures from 60 to 300 °C. Si{sub 3}N{sub 4} experienced significant corrosion above 100 °C. The release rates of silicon and nitrogen follow zero order reaction kinetics and increase with increasing temperature. The molar ratio of dissolved silicon and nitrogen species in the high temperature solutions is the same as that in the solid phase (congruent dissolution). The activation energy for silicon and nitrogen release rates is 75 kJ/mol which agrees well with that of silica dissolution. At 300 °C, the release of aluminum is observed and follows first order reaction kinetics while other minor constituents including Ti and Y are highly enriched on the corrosion films due to the low solubility of their oxides.

  14. Solute strengthening effects for 316 stainless steel at elevated temperature

    International Nuclear Information System (INIS)

    Park, Nam Ju; Lee, Sang Mae

    1986-01-01

    The inelastic behavior of 316 stainless steel is studied in order to investigate the solute strengthening effects. The Arrhenius-type rate equation with inclusion of the Voce-type evolution phenomenon is extended by addition of solute strengthening term to the isotropic work hardening effect. Changing of strain rate and temperature during the tension tests, we found that the strong work hardening for the inelastic of 316 stainless steel resulted from the vacancy-interstitial pair mechanism. Thus, the calculated results using the extended constitutive equations including solute effect due to the vacancy-interstitial pair mechanism were found to be in good agreement with the stress-strain curves obtained from the tension tests. (Author)

  15. Excitation temperature of a solution plasma during nanoparticle synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Genki, E-mail: genki@eng.hokudai.ac.jp; Nakasugi, Yuki; Akiyama, Tomohiro [Center for Advanced Research of Energy and Materials, Hokkaido University, Sapporo 060-8628 (Japan)

    2014-08-28

    Excitation temperature of a solution plasma was investigated by spectroscopic measurements to control the nanoparticle synthesis. In the experiments, the effects of edge shielding, applied voltage, and electrode material on the plasma were investigated. When the edge of the Ni electrode wire was shielded by a quartz glass tube, the plasma was uniformly generated together with metallic Ni nanoparticles. The emission spectrum of this electrode contained OH, H{sub α}, H{sub β}, Na, O, and Ni lines. Without an edge-shielded electrode, the continuous infrared radiation emitted at the edge created a high temperature on the electrode surface, producing oxidized coarse particles as a result. The excitation temperature was estimated from the Boltzmann plot. When the voltages were varied at the edge-shielded electrode with low average surface temperature by using different electrolyte concentrations, the excitation temperature of current-concentration spots increased with an increase in the voltage. The size of the Ni nanoparticles decreased at high excitation temperatures. Although the formation of nanoparticles via melting and solidification of the electrode surface has been considered in the past, vaporization of the electrode surface could occur at a high excitation temperature to produce small particles. Moreover, we studied the effects of electrodes of Ti, Fe, Ni, Cu, Zn, Zr, Nb, Mo, Pd, Ag, W, Pt, Au, and various alloys of stainless steel and Cu–Ni alloys. With the exception of Ti, the excitation temperatures ranged from 3500 to 5500 K and the particle size depended on both the excitation temperature and electrode-material properties.

  16. Solution-phase synthesis of nanomaterials at low temperature

    Science.gov (United States)

    Zhu, Yongchun; Qian, Yitai

    2009-01-01

    This paper reviews the solution-phase synthesis of nanoparticles via some routes at low temperatures, such as room temperature route, wave-assisted synthesis (γ-irradiation route and sonochemical route), directly heating at low temperatures, and hydrothermal/solvothermal methods. A number of strategies were developed to control the shape, the size, as well as the dispersion of nanostructures. Using diethylamine or n-butylamine as solvent, semiconductor nanorods were yielded. By the hydrothermal treatment of amorphous colloids, Bi2S3 nanorods and Se nanowires were obtained. CdS nanowires were prepared in the presence of polyacrylamide. ZnS nanowires were obtained using liquid crystal. The polymer poly (vinyl acetate) tubule acted as both nanoreactor and template for the CdSe nanowire growth. Assisted by the surfactant of sodium dodecyl benzenesulfonate (SDBS), nickel nanobelts were synthesized. In addition, Ag nanowires, Te nanotubes and ZnO nanorod arrays could be prepared without adding any additives or templates.

  17. A free-volume modification of GEM-QC to correlate VLE and LLE in polymer solutions

    International Nuclear Information System (INIS)

    Radfarnia, H.R.; Taghikhani, V.; Ghotbi, C.; Khoshkbarchi, M.K.

    2004-01-01

    The generalized quasi-chemical (GEM-QC) model proposed by Wang and Vera is modified to correlate better the phase equilibrium and to overcome the shortcoming of the original model to predict the lower critical solution temperature (LCST) of binary polymer solutions. This shortcoming is mainly because the GEM-QC model does not consider the effect of free-volume, which is important in systems containing molecules with large size differences. The proposed modification is based on replacing the combinatorial term of the GEM-QC model by a term proposed by Kontogerogis et al., which includes the effect of the free-volume. The main advantage of the free volume generalized quasi-chemical (GEM-QC-FV) model over the original GEM-QC is its ability to predict the phase behaviour of binary polymer solutions with LCST behaviour. In addition, the free volume UNIQUAC (UNIQUAC-FV) model is used to correlate VLE and LLE experimental data for binary polymer solutions. The comparison of the results obtained from the GEM-QC-FV model and the UNIQUAC-FV model shows the superiority of the GEM-QC-FV model in correlating the VLE and LLE experimental data for binary polymer solutions

  18. Radiation chemistry of aqueous solutions of hydrazine at elevated temperatures: Pt. 2. Solutions containing oxygen

    International Nuclear Information System (INIS)

    Buxton, G.V.; Stuart, C.R.

    1997-01-01

    Here, we investigate the effects of oxygen on the radiation chemistry of hydrazine at elevated temperatures. The chemistry of this system is important to reactor coolant chemistry, particularly under start-up conditions when hydrazine is added to suppress corrosion which would otherwise be caused by the ingress of oxygen. The radiation chemistry of aqueous solutions of hydrazine has been investigated previously in the presence of oxygen by Ershov et al., but only at room temperature. In those experiments, both steady-state γ-radiolysis and pulse radiolysis were used to deduce the mechanism of decomposition of hydrazine in the presence of oxygen. (author)

  19. Radiolysis of phenol in aqueous solution at elevated temperatures

    International Nuclear Information System (INIS)

    Miyazaki, Toyoaki; Katsumura, Yosuke; Lin Mingzhang; Muroya, Yusa; Kudo, Hisaaki; Taguchi, Mitsumasa; Asano, Masaharu; Yoshida, Masaru

    2006-01-01

    γ-Radiolysis and pulse radiolysis of phenol in aqueous solution up to supercritical condition have been carried out. G-values of phenol consumption and product formation have been determined. While dihydroxybenzenes were major products at room temperature, multi-ring compounds and benzene were formed above 300 deg. C. This indicates reaction mechanism was changed above 300 deg. C, where phenoxyl radical plays a predominant role. This is supported by the observation of phenoxyl radical in pulse radiolysis. In supercritical water, the G-values increased with decrease of density

  20. Radiolysis of Aqueous Benzene Solutions at higher temperatures

    International Nuclear Information System (INIS)

    Christensen, H.

    1964-07-01

    Aqueous solutions of benzene have been irradiated with Co γ-rays with doses of up to 2.3 Mrad in the temperature region 100 - 200 C. At 100 C a linear relationship between the phenol concentration and the absorbed dose was obtained, but at 150 C and at higher temperatures the rate of the phenol formation increased significantly after an initial constant period. With higher doses the rate decreased again, falling almost to zero at 200 C after a dose of 2.2 Mrad. The G value of phenol in the initial linear period increased from 2.8 at 100 C to 8.0 at 200 C. The reaction mechanism is discussed and reactions constituting a chain reaction are suggested. The result of the addition of iron ions and of a few inorganic oxides to the system is presented and briefly discussed

  1. Radiolysis of Aqueous Benzene Solutions at higher temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, H

    1964-07-15

    Aqueous solutions of benzene have been irradiated with Co {gamma}-rays with doses of up to 2.3 Mrad in the temperature region 100 - 200 C. At 100 C a linear relationship between the phenol concentration and the absorbed dose was obtained, but at 150 C and at higher temperatures the rate of the phenol formation increased significantly after an initial constant period. With higher doses the rate decreased again, falling almost to zero at 200 C after a dose of 2.2 Mrad. The G value of phenol in the initial linear period increased from 2.8 at 100 C to 8.0 at 200 C. The reaction mechanism is discussed and reactions constituting a chain reaction are suggested. The result of the addition of iron ions and of a few inorganic oxides to the system is presented and briefly discussed.

  2. Isotopic equilibria between sulphur solute species at high temperature

    International Nuclear Information System (INIS)

    Robinson, B.W.

    1978-01-01

    Sulphur solute species in ore solutions and geothermal discharges include HSO 4 - , SO 4 2- , H 2 S, and HS - , as well as the ion-paired species, NaHS 0 , NaHSO 4 - and Na 2 SO 4 0 . Observed sulphate-sulphide fractionation factors and the rates of attainment of isotopic equilibrium are likely to depend on the nature of the sulphur species actually taking part in these isotopic equilibria. Preliminary experiments in alkaline solution (pH 10.1 at 20 0 C) were carried out in a gold cell. No significant isotope fractionation was observed between the SO 4 2- and HS - in 29 days at 200 0 C, 63days at 300 0 C, or 90 days at 250 0 C. However, similar experiments at 350 0 C in sealed gold capsules at room temperature pH 8.5 showed slow exchange(t( 1 / 2 ) was calculated to be 510 days for the SO 4 2- -HS - exchange reaction using the theoretical fractionation of 20.2 0 / 00 ). The addition of NaCl appeared to have no affect on the exchange. However, pH strongly controls the reaction rate, and exchange probably involves H 2 S and the HSO 4 - ion. Additional preliminary experiments were conducted with a fivefold increase in the sulphur concentration; a decrease in t( 1 / 2 ) to 142 days resulted. Some inter-relationship between sulphur concentration and exchange rate thus exists. The important controlling parameters of isotope exchange (temperature, pH, and ΣS) can be seen to have influenced exchange in natural systems.(auth.)

  3. Low-Temperature Solution Processable Electrodes for Piezoelectric Sensors Applications

    Science.gov (United States)

    Tuukkanen, Sampo; Julin, Tuomas; Rantanen, Ville; Zakrzewski, Mari; Moilanen, Pasi; Lupo, Donald

    2013-05-01

    Piezoelectric thin-film sensors are suitable for a wide range of applications from physiological measurements to industrial monitoring systems. The use of flexible materials in combination with high-throughput printing technologies enables cost-effective manufacturing of custom-designed, highly integratable piezoelectric sensors. This type of sensor can, for instance, improve industrial process control or enable the embedding of ubiquitous sensors in our living environment to improve quality of life. Here, we discuss the benefits, challenges and potential applications of piezoelectric thin-film sensors. The piezoelectric sensor elements are fabricated by printing electrodes on both sides of unmetallized poly(vinylidene fluoride) film. We show that materials which are solution processable in low temperatures, biocompatible and environmental friendly are suitable for use as electrode materials in piezoelectric sensors.

  4. Temperature effects on solute diffusion and adsorption in differently compacted kaolin clay

    DEFF Research Database (Denmark)

    Mon, Ei Ei; Hamamoto, Shoichiro; Kawamoto, Ken

    2016-01-01

    Effects of soil temperature on the solute diffusion process in soils are important since subsurface temperature variation affects solute transport such as a fertilizer movement, leaching of salt, and pollutant movement to groundwater aquifers. However, the temperature dependency on the solute dif...

  5. Isopiestic studies of aqueous solutions at elevated temperatures

    International Nuclear Information System (INIS)

    Holmes, H.F.; Mesmer, R.E.

    1981-01-01

    Isopiestic measurements have been made on SrCl 2 (aq) and BaCl 2 (aq) over the temperature range 382.96 to 473.61 K with NaCl(aq) as the reference solution for the calculation of osmotic coefficients. The molalities corresponded to NaCl(aq) molalities ranging from 0.6 to 6.5 mol kg -1 . An ion-interaction model was fitted to the osmotic coefficients of SrCl 2 (aq) and BaCl 2 (aq) with a standard deviation of fit (in the osmotic coefficient) ranging from 0.0007 to 0.0048. Parameters derived from the fit were used to calculate the activity coefficients. The osmotic and activity coefficients decrease with increasing temperature and become less dependent on molality. Previous isopiestic results between 318 and 394 K agree with the present study. Activity coefficients from electrochemical measurements between 283.15 and 343.15 K are not consistent with the isopiestic results. (author)

  6. Stress corrosion cracking of austenitic stainless steel in glycerol solution and chloride solution at elevated temperature

    International Nuclear Information System (INIS)

    Haftirman; Maruhum Tua Lubis

    2009-01-01

    Stress Corrosion Cracking (SCC) is an environmentally assisted failure caused by exposure to a corrodant while under a sustained tensile stress. SCC is most often rapid, unpredictable and catastrophic. Failure can occur in as little as a few hours or take years to happen. Most alloys are susceptible to SCC in one or more environments requiring careful consideration of alloy type in component design. In aqueous chloride environments austenitic stainless steels and many nickel based alloys are known to perform poorly. One of products Oleo chemical is glycerol solution. Glycerol solution contains chloride with concentration 50 ppm - 150 ppm. Austenitic stainless steel is usually used in distillation construction tank and pipe line of glycerol. Material AISI 304 will be failure in this glycerol solution with this concentration in 5 years. In production process, concentration of chloride in glycerol becomes more than 150 ppm at temperature 150 degree Celsius. The reason is that the experiment I conducted in high chloride with concentration such as 6000 ppm, 9000 ppm, and 12000 ppm. The stress corrosion cracking of the austenitic stainless steels of types AISI 304, 316 and 316L in glycerol solution at elevated temperature 150 degree Celsius is investigated as a function variation of chloride concentration, namely 50, 6000, 9000 and 12000 ppm using a constant load method with two kinds of initial tensile stress as 50 % and 70 % yield strength. The experiment uses a spring loaded fixture type and is based on ASTM G49 for experiment method, and E292 for geometry of specimen. Pitting corrosion occurs on the surface specimen until the stress level reaches the ultimate strength. Pitting corrosion attack and depletion occur on the surface as initiation of SCC failure as the stress reaches the ultimate strength. Failure has occurred in catastrophic brittle fracture type of transgranular. AISI 304 was more susceptible for all conditions. In chloride solution with concentration of

  7. Temperature-Responsive Biocompatible Copolymers Incorporating Hyperbranched Polyglycerols for Adjustable Functionality

    Directory of Open Access Journals (Sweden)

    Alan J. House

    2011-08-01

    Full Text Available Temperature-triggered copolymers are proposed for a number of bio-applications but there is no ideal material platform, especially for injectable drug delivery. Options are needed for degradable biomaterials that not only respond to temperature but also easily accommodate linkage of active molecules. A first step toward realizing this goal is the design and synthesis of the novel materials reported herein. A multifunctional macromer, methacrylated hyperbranched polyglycerol (HPG-MA with an average of one acrylate unit per copolymer, was synthesized and copolymerized with N-isopropylacrylamide (NIPAAm, hydroxyethyl methacrylate-polylactide (HEMAPLA and acrylic acid (AAc. The potential to fully exploit the copolymers by modification of the multiple HPG hydroxyl groups will not be discussed here. Instead, this report focuses on the thermoresponsive, biocompatible, and degradation properties of the material. Poly(NIPAAm-co-HEMAPLA-co-AAc-co-HPG-MA displayed increasing lower critical solution temperatures (LCST as the HPG content increased over a range of macromer ratios. For the copolymer with the maximum HPG incorporation (17%, the LCST was ~30 °C. In addition, this sample showed no toxicity when human uterine fibroid cells were co-cultured with the copolymer for up to 72 h. This copolymer lost approximately 92% of its mass after 17 hours at 37 °C. Thus, the reported biomaterials offer attractive properties for the design of drug delivery systems where orthogonally triggered mechanisms of therapeutic release in relatively short time periods would be attractive.

  8. Effect of peritoneal lavage solution temperature on body temperature in anaesthetised cats and small dogs.

    Science.gov (United States)

    Barnes, D C; Leece, E A; Trimble, T A; Demetriou, J L

    2017-05-20

    A prospective, randomised, non-blinded, clinical study to assess the effect of peritoneal lavage using warmed fluid on body temperature in anesthetised cats and dogs of less than 10 kg body mass undergoing coeliotomy. A standardised anaesthetic protocol was used. Oesophageal and rectal temperatures were measured at various time points. At the end of surgery, group 1 patients (n=10) were lavaged with 200 ml/kg sterile isotonic saline at 34±1°C and group 2 (n=10) at 40±1°C. Groups were similar with respect to age, mass, body condition and surgical incision length. Duration of anaesthesia, surgical procedures and peritoneal lavage was similar between groups. Linear regression showed no significant change in oesophageal temperature during the lavage period for group 1 (P=0.64), but a significant increase for group 2 patients (Ptemperature changes of -0.5°C (from (36.3°C to 35.9°C) and +0.9°C (from 35.4°C to 36.3°C), respectively. Similar results were found for rectal temperature, with mean changes of -0.5°C and +0.8°C (P=0.922 and 0.045), respectively. The use of isotonic crystalloid solution for peritoneal lavage at a temperature of 40±1°C significantly warms small animal patients, when applied in a clinical setting, compared with lavage solution at 34±1°C. British Veterinary Association.

  9. EXACT SOLUTION TO FINITE TEMPERATURE SFDM: NATURAL CORES WITHOUT FEEDBACK

    International Nuclear Information System (INIS)

    Robles, Victor H.; Matos, T.

    2013-01-01

    Recent high-quality observations of low surface brightness (LSB) galaxies have shown that their dark matter (DM) halos prefer flat central density profiles. However, the standard cold dark matter model simulations predict a more cuspy behavior. One mechanism used to reconcile the simulations with the observed data is the feedback from star formation. While this mechanism may be successful in isolated dwarf galaxies, its success in LSB galaxies remains unclear. Additionally, the inclusion of too much feedback in the simulations is a double-edged sword—in order to obtain a cored DM distribution from an initially cuspy one, the feedback recipes usually require one to remove a large quantity of baryons from the center of the galaxies; however, some feedback recipes produce twice the number of satellite galaxies of a given luminosity and with much smaller mass-to-light ratios from those that are observed. Therefore, one DM profile that produces cores naturally and that does not require large amounts of feedback would be preferable. We find both requirements to be satisfied in the scalar field dark matter model. Here, we consider that DM is an auto-interacting real scalar field in a thermal bath at temperature T with an initial Z 2 symmetric potential. As the universe expands, the temperature drops so that the Z 2 symmetry is spontaneously broken and the field rolls down to a new minimum. We give an exact analytic solution to the Newtonian limit of this system, showing that it can satisfy the two desired requirements and that the rotation curve profile is no longer universal.

  10. Thermoresponsive copolymer-grafted SBA-15 porous silica particles for temperature-triggered topical delivery systems

    Directory of Open Access Journals (Sweden)

    S. A. Jadhav

    2017-02-01

    Full Text Available A series of poly(N-isopropylacrylamide-co-acrylamide thermoresponsive random copolymers with different molecular weights and composition were synthesized and characterized by attenuated total reflectance Fourier-transform infrared (ATR-FTIR, differential scanning calorimetry (DSC, size exclusion chromatography (SEC and proton nuclear magnetic resonance (NMR spectroscopy. The lower critical solution temperatures (LCST of the copolymers were tuned by changing the mole ratios of monomers. Copolymer with highest molecular weight and LCST (41.2 °C was grafted on SBA-15 type mesoporous silica particles by a two-step polymer grafting procedure. Bare SBA-15 and the thermoresponsive copolymergrafted (hybrid SBA-15 particles were fully characterized by scanning electron microscope (SEM, ATR-FTIR, thermogravimetric analysis (TGA and Brunauer-Emmett-Teller (BET analyses. The hybrid particles were tested for their efficiency as temperature-sensitive systems for dermal delivery of the antioxidant rutin (quercetin-3-O-rutinoside. Improved control over rutin release by hybrid particles was obtained which makes them attractive hybrid materials for drug delivery.

  11. Effect of solution saturation state and temperature on diopside dissolution

    Directory of Open Access Journals (Sweden)

    Carroll Susan A

    2007-03-01

    Full Text Available Abstract Steady-state dissolution rates of diopside are measured as a function of solution saturation state using a titanium flow-through reactor at pH 7.5 and temperature ranging from 125 to 175°C. Diopside dissolved stoichiometrically under all experimental conditions and rates were not dependent on sample history. At each temperature, rates continuously decreased by two orders of magnitude as equilibrium was approached and did not exhibit a dissolution plateau of constant rates at high degrees of undersaturation. The variation of diopside dissolution rates with solution saturation can be described equally well with a ion exchange model based on transition state theory or pit nucleation model based on crystal growth/dissolution theory from 125 to 175°C. At 175°C, both models over predict dissolution rates by two orders of magnitude indicating that a secondary phase precipitated in the experiments. The ion exchange model assumes the formation of a Si-rich, Mg-deficient precursor complex. Lack of dependence of rates on steady-state aqueous calcium concentration supports the formation of such a complex, which is formed by exchange of protons for magnesium ions at the surface. Fit to the experimental data yields Rate (moldiopsidecm−2s−1=k×10−Ea/2.303RT(aH+2aMg2+n MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaaieaacqWFsbGucqWFHbqycqWF0baDcqWFLbqzcqqGGaaicqGGOaakcqWFTbqBcqWFVbWBcqWFSbaBcqWFGaaicqWFKbazcqWFPbqAcqWFVbWBcqWFWbaCcqWFZbWCcqWFPbqAcqWFKbazcqWFLbqzcqWFGaaicqWFJbWycqWFTbqBdaahaaWcbeqaaiabgkHiTiabikdaYaaakiab=bcaGiab=nhaZnaaCaaaleqabaGaeyOeI0IaeGymaedaaOGaeiykaKIaeyypa0Jaem4AaSMaey41aqRaeeymaeJaeeimaaZaaWbaaSqabeaacqGHsislcqWGfbqrdaWgaaadbaGaemyyaegabeaaliabc+caViabikdaYiabc6caUiabioda

  12. Temperature effects on geotechnical and hydraulic properties of bentonite hydrated with inorganic salt solutions

    DEFF Research Database (Denmark)

    Rashid, H. M. A.; Kawamoto, K.; Saito, T.

    2015-01-01

    © 2015, International Journal of GEOMATE. This study investigated the combined effect of temperature and single-species salt solutions on geotechnical properties (swell index and liquid limit) and hydraulic conductivity of bentonite applying different cation types, concentrations, and temperatures...

  13. Dynamic microscale temperature gradient in a gold nanorod solution measured by diffraction-limited nanothermometry

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chengmingyue; Gan, Xiaosong; Li, Xiangping; Gu, Min, E-mail: mgu@swin.edu.au [Centre for Micro-Photonics, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Victoria 3122 (Australia)

    2015-09-21

    We quantify the dynamic microscale temperature gradient in a gold nanorod solution using quantum-dot-based microscopic fluorescence nanothermometry. By incorporating CdSe quantum dots into the solution as a nanothermometer, precise temperature mapping with diffraction-limited spatial resolution and sub-degree temperature resolution is achieved. The acquired data on heat generation and dissipation show an excellent agreement with theoretical simulations. This work reveals an effective approach for noninvasive temperature regulation with localized nanoheaters in microfluidic environment.

  14. Temperature field conduction solution by incomplete boundary condition

    Energy Technology Data Exchange (ETDEWEB)

    Novakovic, M; Petrasinovic, Lj; Djuric, M [Tehnoloski fakultet, Novi Sad (Yugoslavia); Perovic, N [Institut za Nuklearne Nauke Boris Kidric, Belgrade (Yugoslavia)

    1977-01-01

    The problem of determination of one part boundary conditions temperatures for Fourier partial differential equation when the other part of boundary condition and derivates (heat fluxes) are known is a practical interest as it enables one to determine and accessible temperature by measuring temperatures on other side, of the wall. Method developed and applied here consist of transforming the Fourier partial differential equation by time discretisation in sets of pairs of ordinary differential equations for temperature and heat flux. Such pair of differential equations of first order was solved by Runge-Kutta method. The integration proceeds along space interval simultaneosly for all time intervals. It is interesting to note that this procedure does not require the initial condition.

  15. Solution properties and taste behavior of lactose monohydrate in aqueous ascorbic acid solutions at different temperatures: Volumetric and rheological approach.

    Science.gov (United States)

    Sarkar, Abhijit; Sinha, Biswajit

    2016-11-15

    The densities and viscosities of lactose monohydrate in aqueous ascorbic acid solutions with several molal concentrations m=(0.00-0.08)molkg(-1) of ascorbic acid were determined at T=(298.15-318.15)K and pressure p=101kPa. Using experimental data apparent molar volume (ϕV), standard partial molar volume (ϕV(0)), the slope (SV(∗)), apparent specific volumes (ϕVsp), standard isobaric partial molar expansibility (ϕE(0)) and its temperature dependence [Formula: see text] the viscosity B-coefficient and solvation number (Sn) were determined. Viscosity B-coefficients were further employed to obtain the free energies of activation of viscous flow per mole of the solvents (Δμ1(0≠)) and of the solute (Δμ2(0≠)). Effects of molality, solute structure and temperature and taste behavior were analyzed in terms of solute-solute and solute-solvent interactions; results revealed that the solutions are characterized predominantly by solute-solvent interactions and lactose monohydrate behaves as a long-range structure maker. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Effects of Solution Annealing Temperature on the Galvanic Corrosion Behavior of the Super Duplex Stainless Steels

    Science.gov (United States)

    Lee, Jun-Seob; Jeon, Soon-Hyeok; Park, Yong-Soo

    2013-02-01

    This study investigated the active dissolution of super duplex stainless steel (SDSS) at various solution annealing temperatures. The active dissolutions of the α-phase and γ-phase were compared, and the effects of the surface area ratio on the active dissolutions of both phases were investigated. There were two peaks in the active-passive transition region in the potentiodynamic test in the modified green-death solution. The two peaks changed as the solution annealing temperature was increased from 1050 to 1150 °C. The solution annealing temperature difference affected the critical anodic current densities. This provides useful information for determining the appropriate solution annealing temperature in the modified green-death solution for SDSS.

  17. Immobilization of plutonium from solutions on porous matrices by the method of high temperature sorption

    Energy Technology Data Exchange (ETDEWEB)

    Nardova, A.K.; Filippov, E.A. [All Research Institute of Chemical Technologies, Moscow (Russian Federation); Glagolenko, Y.B. [and others

    1996-05-01

    This report presents the results of investigations of plutonium immobilization from solutions on inorganic matrices with the purpose of producing a solid waste form. High-temperature sorption is described which entails the adsorption of radionuclides from solutions on porous, inorganic matrices, as for example silica gel. The solution is brought to a boil with additional thermal process (calcination) of the saturated granules.

  18. γ-Radiolysis of benzophenone aqueous solution at elevated temperatures up to supercritical condition

    International Nuclear Information System (INIS)

    Miyazaki, Toyoaki; Katsumura, Yosuke; Lin Mingzhang; Muroya, Yusa; Kudo, Hisaaki; Asano, Masaharu; Yoshida, Masaru

    2006-01-01

    A product analysis study of γ-irradiated benzophenone aqueous solutions from room temperature to 400 deg. C has been carried out by the combination of a flow irradiation system and a liquid chromatographic method. At room temperature, the main decomposition products are phenol and hydroxybenzophenone isomers. In high temperature and supercritical water solutions, 9-fluorenone appears as an important product and the G-value of benzophenone consumption depends significantly on the water density under supercritical conditions

  19. Isopiestic studies of aqueous solutions at elevated temperatures

    International Nuclear Information System (INIS)

    Holmes, H.F.; Mesmer, R.E.

    1981-01-01

    Isopiestic measurements have been made for LiCl(aq) and CsCl(aq) over the temperature range 382.96 to 473.61 K. NcCl(aq) served as the reference electrolyte for the calculation of osmotic coefficients and the molalities ranged from about 0.6 to 6 mol kg -1 , for NaCl(aq). An ion-interaction model gave an excellent fit to the experimental osmotic coefficients with a standard error of fit ranging from 0.0004 to 0.0016 in the osmotic coefficient. Parameters obtained from the fit were used to calculate the activity coefficients. The osmotic and activity coefficients both decreased with increasing temperature over this temperature range. LiCl(aq) is somewhat unusual among the alkali-metal chlorides in that the osmotic (and activity) coefficient is much more dependent on molality at the higher molalities and there is no maximum between 273.15 and 373.15 K in the osmotic coefficient as a function of temperature. For both LiCl(aq) and CsCl(aq) there is an excellent correlation between the isopiestic results and the vapor pressures of Lindsay and Liu. Existing electrochemical results between 283.15 and 343.15 K are consistent with the calculated activity coefficients for CsCl(aq). (author)

  20. A Solution-Based Temperature Sensor Using the Organic Compound CuTsPc

    Directory of Open Access Journals (Sweden)

    Shahino Mah Abdullah

    2014-06-01

    Full Text Available An electrochemical cell using an organic compound, copper (II phthalocyanine-tetrasulfonic acid tetrasodium salt (CuTsPc, has been fabricated and investigated as a solution-based temperature sensor. The capacitance and resistance of the ITO/CuTsPc solution/ITO chemical cell has been characterized as a function of temperature in the temperature range of 25–80 °C. A linear response with minimal hysteresis is observed. The fabricated temperature sensor has shown high consistency and sensitive response towards a specific range of temperature values.

  1. Approximate solution of the Saha equation - temperature as an explicit function of particle densities

    International Nuclear Information System (INIS)

    Sato, M.

    1991-01-01

    The Saha equation for a plasma in thermodynamic equilibrium (TE) is approximately solved to give the temperature as an explicit function of population densities. It is shown that the derived expressions for the Saha temperature are valid approximations to the exact solution. An application of the approximate temperature to the calculation of TE plasma parameters is also described. (orig.)

  2. Corrosion behaviour of Alloy 800 in high temperature aqueous solutions: Electrochemical studies

    International Nuclear Information System (INIS)

    Olmedo, A.M.; Villegas, M.; Alvarez, M.G.

    1996-01-01

    The anodic behaviour and passivity breakdown of Alloy 800 in aqueous solutions of sodium chloride, sodium sulphate and sodium bicarbonate were studied by electrochemical techniques in the temperature range from 60 C to 280 C. The pitting resistance and pitting morphology of the alloy in chloride plus sulphate and chloride plus bicarbonate mixtures, at 60 C and 280 C, were also examined. Increasing bicarbonate or sulphate additions to chloride solutions shift the characteristic pitting potential of Alloy 800 to higher values, both at low and high temperatures. Changes in pitting morphology were observed in sulphate containing solutions while the morphology of the attack found in bicarbonate containing solutions was similar to that in pure chloride solutions. Finally, no localized or substantial generalized corrosion was detected in pure sulphate or bicarbonate solutions at any temperature. (orig.)

  3. Effects of Temperature on Solute Transport Parameters in Differently-Textured Soils at Saturated Condition

    Science.gov (United States)

    Hamamoto, S.; Arihara, M.; Kawamoto, K.; Nishimura, T.; Komatsu, T.; Moldrup, P.

    2014-12-01

    Subsurface warming driven by global warming, urban heat islands, and increasing use of shallow geothermal heating and cooling systems such as the ground source heat pump, potentially causes changes in subsurface mass transport. Therefore, understanding temperature dependency of the solute transport characteristics is essential to accurately assess environmental risks due to increased subsurface temperature. In this study, one-dimensional solute transport experiments were conducted in soil columns under temperature control to investigate effects of temperature on solute transport parameters, such as solute dispersion and diffusion coefficients, hydraulic conductivity, and retardation factor. Toyoura sand, Kaolin clay, and intact loamy soils were used in the experiments. Intact loamy soils were taken during a deep well boring at the Arakawa Lowland in Saitama Prefecture, Japan. In the transport experiments, the core sample with 5-cm diameter and 4-cm height was first isotropically consolidated, whereafter 0.01M KCl solution was injected to the sample from the bottom. The concentrations of K+ and Cl- in the effluents were analyzed by an ion chromatograph to obtain solute breakthrough curves. The solute transport parameters were calculated from the breakthrough curves. The experiments were conducted under different temperature conditions (15, 25, and 40 oC). The retardation factor for the intact loamy soils decreased with increasing temperature, while water permeability increased due to reduced viscosity of water at higher temperature. Opposite, the effect of temperature on solute dispersivity for the intact loamy soils was insignificant. The effects of soil texture on the temperature dependency of the solute transport characteristics will be further investigated from comparison of results from differently-textured samples.

  4. Tuning of thermally induced sol-to-gel transitions of moderately concentrated aqueous solutions of doubly thermosensitive hydrophilic diblock copolymers poly(methoxytri(ethylene glycol) acrylate)-b-poly(ethoxydi(ethylene glycol) acrylate-co-acrylic acid).

    Science.gov (United States)

    Jin, Naixiong; Zhang, Hao; Jin, Shi; Dadmun, Mark D; Zhao, Bin

    2012-03-15

    We report in this article a method to tune the sol-to-gel transitions of moderately concentrated aqueous solutions of doubly thermosensitive hydrophilic diblock copolymers that consist of two blocks exhibiting distinct lower critical solution temperatures (LCSTs) in water. A small amount of weak acid groups is statistically incorporated into the lower LCST block so that its LCST can be tuned by varying solution pH. Well-defined diblock copolymers, poly(methoxytri(ethylene glycol) acrylate)-b-poly(ethoxydi(ethylene glycol) acrylate-co-acrylic acid) (PTEGMA-b-P(DEGEA-co-AA)), were prepared by reversible addition-fragmentation chain transfer polymerization and postpolymerization modification. PTEGMA and PDEGEA are thermosensitive water-soluble polymers with LCSTs of 58 and 9 °C, respectively, in water. A 25 wt % aqueous solution of PTEGMA-b-P(DEGEA-co-AA) with a molar ratio of DEGEA to AA units of 100:5.2 at pH = 3.24 underwent multiple phase transitions upon heating, from a clear, free-flowing liquid (sol-to-gel transition temperature (T(sol-gel)) shifted to higher values, while the gel-to-sol transition (T(gel-sol)) and the clouding temperature (T(clouding)) of the sample remained essentially the same. These transitions and the tunability of T(sol-gel) originated from the thermosensitive properties of two blocks of the diblock copolymer and the pH dependence of the LCST of P(DEGEA-co-AA), which were confirmed by dynamic light scattering and differential scanning calorimetry studies. Using the vial inversion test method, we mapped out the C-shaped sol-gel phase diagrams of the diblock copolymer in aqueous buffers in the moderate concentration range at three different pH values (3.24, 5.58, and 5.82, all measured at ~0 °C). While the upper temperature boundaries overlapped, the lower temperature boundary shifted upward and the critical gelation concentration increased with the increase of pH. The AA content in PTEGMA-b-P(DEGEA-co-AA) was found to have a significant

  5. The effects of heated and room-temperature abdominal lavage solutions on core body temperature in dogs undergoing celiotomy.

    Science.gov (United States)

    Nawrocki, Michael A; McLaughlin, Ron; Hendrix, P K

    2005-01-01

    To document the magnitude of temperature elevation obtained with heated lavage solutions during abdominal lavage, 18 dogs were lavaged with sterile isotonic saline intraoperatively (i.e., during a celiotomy). In nine dogs, room-temperature saline was used. In the remaining nine dogs, saline heated to 43+/-2 degrees C (110+/-4 degrees F) was used. Esophageal, rectal, and tympanic temperatures were recorded every 60 seconds for 15 minutes after initiation of the lavage. Temperature levels decreased in dogs lavaged with room-temperature saline. Temperature levels increased significantly in dogs lavaged with heated saline after 2 to 6 minutes of lavage, and temperatures continued to increase throughout the 15-minute lavage period.

  6. Temperature Profile of the Solution Vessel of an Accelerator-Driven Subcritical Fissile Solution System

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Steven Karl [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Determan, John C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-14

    Dynamic System Simulation (DSS) models of fissile solution systems have been developed and verified against a variety of historical configurations. DSS techniques have been applied specifically to subcritical accelerator-driven systems using fissile solution fuels of uranium. Initial DSS models were developed in DESIRE, a specialized simulation scripting language. In order to tailor the DSS models to specifically meet needs of system designers they were converted to a Visual Studio implementation, and one of these subsequently to National Instrument’s LabVIEW for human factors engineering and operator training. Specific operational characteristics of subcritical accelerator-driven systems have been examined using a DSS model tailored to this particular class using fissile fuel.

  7. Temperature Profile of the Solution Vessel of an Accelerator-Driven Subcritical Fissile Solution System

    International Nuclear Information System (INIS)

    Klein, Steven Karl; Determan, John C.

    2015-01-01

    Dynamic System Simulation (DSS) models of fissile solution systems have been developed and verified against a variety of historical configurations. DSS techniques have been applied specifically to subcritical accelerator-driven systems using fissile solution fuels of uranium. Initial DSS models were developed in DESIRE, a specialized simulation scripting language. In order to tailor the DSS models to specifically meet needs of system designers they were converted to a Visual Studio implementation, and one of these subsequently to National Instrument's LabVIEW for human factors engineering and operator training. Specific operational characteristics of subcritical accelerator-driven systems have been examined using a DSS model tailored to this particular class using fissile fuel.

  8. Volumetric and viscometric studies of some drugs in aqueous solutions at different temperatures

    International Nuclear Information System (INIS)

    Dhondge, Sudhakar S.; Zodape, Sangesh P.; Parwate, Dilip V.

    2012-01-01

    Highlights: ► Study of aqueous solutions of biologically important compounds has been reported. ► MH is used for treating type II diabetes, RH is in treatment of peptic ulcer and TH is used to treat severe pain. ► All the compounds act as structure makers by volumetric studies. ► MH and RH act as weak structure breakers and TH acts as a weak structure maker by viscometric studies. - Abstract: Density and viscosity measurements are reported for aqueous solutions of the drugs like Metformin hydrochloride (MH), Ranitidine hydrochloride (RH) and Tramadol hydrochloride (TH) at different temperatures T = (288.15, 298.15, and 308.15) K within the concentration range (0 to 0.15) mol · kg −1 . The density and viscosity data are used to obtain apparent molar volume of solute (φ V ) and relative viscosity (η r ) of aqueous solutions at different temperatures. The limiting apparent molar volume of solute (φ V 0 ), limiting apparent molar expansivity (φ E 0 ), thermal expansion coefficient (α ∗ ), hydration number (n h ), Jones–Dole equation viscosity A and B coefficients, experimental slope (S V ) at different temperatures, and temperature coefficient of Bi.e.(dB/dT) at T = 298.15 K were also obtained. The results obtained have been interpreted in terms of solute–solvent and solute–solute interactions and structure making/breaking ability of solute in the aqueous solution.

  9. Effects of Temperature on Aggregation Kinetics of Graphene Oxide in Aqueous Solutions

    Science.gov (United States)

    Wang, M.; Gao, B.; Tang, D.; Sun, H.; Yin, X.; Yu, C.

    2017-12-01

    Temperature may play an important role in controlling graphene oxide (GO) stability in aqueous solutions, but it has been overlooked in the literature. In this work, laboratory experiments were conducted to determine the effects of temperature (6, 25, and 40 °C) on GO aggregation kinetics under different combinations of ionic strength, cation type, humic acid (HA) concentration by monitoring GO hydrodynamic radii and attachment efficiencies. The results showed that, without HA, temperature increase promoted GO aggregation in both monovalent (Na+ and K+) and divalent (Ca2+) solutions. This phenomenon might be caused by multiple processes including enhanced collision frequency, enhanced cation dehydration, and reduced electrostatic repulsion. The presence of HA introduced steric repulsion forces that enhanced GO stability and temperature showed different effects GO aggregation kinetics in monovalent and divalent electrolytes. In monovalent electrolytes, cold temperature diminished the steric repulsion of HA-coated GO. As a result, the fastest increasing rate of GO hydrodynamic radius and the smallest critical coagulation concentration value appeared at the lowest temperature (6 °C). Conversely, in divalent electrolyte solutions with HA, high temperate favored GO aggregation, probably because the interactions between Ca2+ and HA increased with temperature resulting in lower HA coating on GO. Findings of this work emphasized the importance of temperature as well as solution chemistry on the stability and fate of GO nanoparticles in aquatic environment.

  10. Twin solution calorimeter determines heats of formation of alloys at high temperatures

    Science.gov (United States)

    Darby, J. B., Jr.; Kleb, R.; Kleppa, O. J.

    1968-01-01

    Calvert-type, twin liquid metal solution calorimeter determines the heats of formation of transition metal alloys at high temperatures. The twin differential calorimeter measures the small heat effects generated over extended periods of time, has maximum operating temperature of 1073 degrees K and an automatic data recording system.

  11. Effect of temperature on the behavior of surface properties of alcohols in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Carmen M. [Facultad de Ciencias, Universidad Nacional de Colombia, Bogota (Colombia)], E-mail: cmromeroi@unal.edu.co; Jimenez, Eulogio [Facultade de Ciencias, Universidade da Coruna (Spain); Suarez, Felipe [Facultad de Ciencias, Universidad Nacional de Colombia, Bogota (Colombia)

    2009-04-15

    The influence of temperature on the behavior of surface properties of aqueous solutions has often been used to obtain information about solute structural effects on water. In this work, we present experimental results for surface tension of aqueous solutions of n-pentanol, n-hexanol, n-heptanol, and n-octanol at T = (283.15, 288.15, 293.15, 298.15, 303.15, and 308.15) K at several concentrations. The results were used to evaluate the limiting experimental slopes of surface tension with respect to mole fraction and the hydrophobicity constant of the Connors model at each temperature. The thermodynamic behavior of aqueous alcohol solutions is discussed in terms of the effect of the hydrocarbon chain on water structure. The temperature dependence of the limiting slopes of surface tension with respect to mole fraction, as well as the hydrophobicity constant derived from surface measurements, is interpreted in terms of alcohol hydration.

  12. Effect of temperature on the behavior of surface properties of alcohols in aqueous solution

    International Nuclear Information System (INIS)

    Romero, Carmen M.; Jimenez, Eulogio; Suarez, Felipe

    2009-01-01

    The influence of temperature on the behavior of surface properties of aqueous solutions has often been used to obtain information about solute structural effects on water. In this work, we present experimental results for surface tension of aqueous solutions of n-pentanol, n-hexanol, n-heptanol, and n-octanol at T = (283.15, 288.15, 293.15, 298.15, 303.15, and 308.15) K at several concentrations. The results were used to evaluate the limiting experimental slopes of surface tension with respect to mole fraction and the hydrophobicity constant of the Connors model at each temperature. The thermodynamic behavior of aqueous alcohol solutions is discussed in terms of the effect of the hydrocarbon chain on water structure. The temperature dependence of the limiting slopes of surface tension with respect to mole fraction, as well as the hydrophobicity constant derived from surface measurements, is interpreted in terms of alcohol hydration

  13. Temperature duality on Riemann surface and cosmological solutions for genus g = 1 and 2

    International Nuclear Information System (INIS)

    Yan Jun; Wang Shunjin

    1999-01-01

    A bosonic string model at finite temperature on the gravitation g μν and the dilaton φ background field is examined. Moreover, the duality relation of energy momentum tensor on high genus Riemann surface is derived. At the same time, the temperature duality invariance for the action of string gas matter is proved in 4-D Robertson-Walker metric, the string cosmological solutions and temperature duality of the equations of motion for genus g = 1 and 2 are also investigated

  14. Poly(N-isopropylacrylamide) hydrogel-based shape-adjustable polyimide films triggered by near-human-body temperature.

    Science.gov (United States)

    Huanqing Cui; Xuemin Du; Juan Wang; Tianhong Tang; Tianzhun Wu

    2016-08-01

    Hydrogel-based shape-adjustable films were successfully fabricated via grafting poly(N-isopropylacrylamide) (PNIPAM) onto one side of polyimide (PI) films. The prepared PI-g-PNIPAM films exhibited rapid, reversible, and repeatable bending/unbending property by heating to near-human-body temperature (37 °C) or cooling to 25 °C. The excellent property of PI-g-PNIPAM films resulted from a lower critical solution temperature (LCST) of PNIPAM at about 32 °C. Varying the thickness of PNIPAM hydrogel layer regulated the thermo-responsive shape bending degree and response speed of PI-g-PNIPAM films. The thermo-induced shrinkage of hydrogel layers can tune the curvature of PI films, which have potential applications in the field of wearable and implantable devices.

  15. Effects of sorption and temperature on solute transport in unsaturated steady flow

    International Nuclear Information System (INIS)

    Fuentes, H.R.; Polzer, W.L.; Essington, E.H.

    1986-01-01

    It is known that temperature affects physical and chemical processes and that these processes may alter the transport of solutes in the environment. Laboratory column studies were performed in unsaturated flow conditions with a composite pulse containing iodide, cobalt, cesium and strontium each at 10 -3 M. The experiments were performed with Bandelier Tuff and produced breakthrough curves that indicate significant changes in transport due to a temperature change from 25 0 C to 5 0 C for nonconservative solutes. Also, the interpretation of the temperature and sorption data suggest that the differences in transport between 5 0 C and 25 0 C for nonconservative solutes may be predicted in a qualitative manner from batch equilibrium and nonequilibrium sorption data and the theory of sorption used in deriving the modified Freundlich isotherm equation. These effects should be of concern in modeling and management of spills and waste disposal within this range of environmental temperatures

  16. High-temperature extraction of rhenium from sulfuric acid solutions with trialkylamines

    International Nuclear Information System (INIS)

    Gladyhev, V.P.; Andreeva, N.N.; Kim, E.M.; Kovaleva, S.V.

    1985-01-01

    This paper attempts to determine the possibility of conducting high-temperature extraction of rhenium from sulfuric acid solutions with trialkylamines (TAA) using higher hydrocarbon-paraffin mixtures as the diluent of the extraction system. Substitution of kerosene by paraffin in the extraction system would permit decreasing the danger of fire and explosions during he extraction process. In extracting rhenium from industrial solutions with a melt of higher paraffins containing TAA and alcohols, the extraction system can be continously heated in heat exchangers through which washing sulfuric acid passes and then goes to the extractor. This permits utilizing the heat and decreases the temperature of the solutions for extraction to the optimum temperatures. Extraction of rhenium with a melt of trioctylamine in paraffin obeys the same mechanisms as high-temperature extraction of ruthenium (IV) by amines in kerosene and aromatic hydrocarbons

  17. Probing Ionic Liquid Aqueous Solutions Using Temperature of Maximum Density Isotope Effects

    Directory of Open Access Journals (Sweden)

    Mohammad Tariq

    2013-03-01

    Full Text Available This work is a new development of an extensive research program that is investigating for the first time shifts in the temperature of maximum density (TMD of aqueous solutions caused by ionic liquid solutes. In the present case we have compared the shifts caused by three ionic liquid solutes with a common cation—1-ethyl-3-methylimidazolium coupled with acetate, ethylsulfate and tetracyanoborate anions—in normal and deuterated water solutions. The observed differences are discussed in terms of the nature of the corresponding anion-water interactions.

  18. Etching characteristics of a CR-39 track detector at room temperature in different etching solutions

    International Nuclear Information System (INIS)

    Dajko, G.

    1991-01-01

    Investigations were carried out to discover how the etching characteristics of CR-39 detectors change with varying conditions of the etching process. Measurements were made at room temperature in pure NaOH and KOH solutions; in different alcoholic KOH solutions (PEW solution, i.e. potassium hydroxide, ethyl alcohol, water); and in NaOH and KOH solutions containing different additives. The bulk etching rate of the detector (V B ) and the V (= V T /V B ) function, i.e. track to bulk etch rates ratio, for 6.1 MeV α-particles, were measured systematically. (author)

  19. The elastic solid solution model for minerals at high pressures and temperatures

    Science.gov (United States)

    Myhill, R.

    2018-02-01

    Non-ideality in mineral solid solutions affects their elastic and thermodynamic properties, their thermobaric stability, and the equilibrium phase relations in multiphase assemblages. At a given composition and state of order, non-ideality in minerals is typically modelled via excesses in Gibbs free energy which are either constant or linear with respect to pressure and temperature. This approach has been extremely successful when modelling near-ideal solutions. However, when the lattice parameters of the solution endmembers differ significantly, extrapolations of thermodynamic properties to high pressures using these models may result in significant errors. In this paper, I investigate the effect of parameterising solution models in terms of the Helmholtz free energy, treating volume (or lattice parameters) rather than pressure as an independent variable. This approach has been previously applied to models of order-disorder, but the implications for the thermodynamics and elasticity of solid solutions have not been fully explored. Solid solution models based on the Helmholtz free energy are intuitive at a microscopic level, as they automatically include the energetic contribution from elastic deformation of the endmember lattices. A chemical contribution must also be included in such models, which arises from atomic exchange within the solution. Derivations are provided for the thermodynamic properties of n-endmember solutions. Examples of the use of the elastic model are presented for the alkali halides, pyroxene, garnet, and bridgmanite solid solutions. Elastic theory provides insights into the microscopic origins of non-ideality in a range of solutions, and can make accurate predictions of excess enthalpies, entropies, and volumes as a function of volume and temperature. In solutions where experimental data are sparse or contradictory, the Helmholtz free energy approach can be used to assess the magnitude of excess properties and their variation as a function

  20. The chemistry of high temperature phosphate solutions in relation to steam generation

    International Nuclear Information System (INIS)

    Broadbent, D.; Lewis, G.G.; Wetton, E.A.M.

    1978-01-01

    The problems associated with the use of phosphate for chemical treatment of the P.W.R. secondary circuit have prompted renewed interest in the physical chemistry of these solutions. Solubility and phase studies have been carried out at 250, 300 and 350 0 C with solutions having sodium to phosphate ratios from 1.0 to above 3.0. A solid phase of ratio about 2.8 exists in equilibrium with a wide range of saturated solution compositions at each temperature. Invariant points at which three phases are in equilibrium have been identified and at the two higher temperatures a region of liquid-liquid immiscibility occurs. Phase diagrams have been constructed for each temperature from which it is possible to predict the compositional changes occurring during the isothermal evaporation process. The corrosivity of these phosphate solutions to a range of steel alloys is being studied, the results reported in the present work, however, are confined to mild steel in the temperature and phosphate composition ranges of the phase studies. The corrosion of mild steel is generally considerably less than in sodium hydroxide solutions of equivalent concentration. The dependence of corrosion rate on sodium and phosphate concentrations in not readily explicable in terms of the solubility and phase studies and it is thought that the solubility of iron in the phosphate solutions is an important rate-determining factor since several complex compounds containing sodium, phosphorus and ferrous iron are present in the corrosion films. (author)

  1. Corrosion studies of austenitic and duplex stainless steels in aqueous lithium bromide solution at different temperatures

    International Nuclear Information System (INIS)

    Igual Munoz, A.; Garcia Anton, J.; Lopez Nuevalos, S.; Guinon, J.L.; Perez Herranz, V.

    2004-01-01

    The corrosion behavior of three stainless steels EN 14311, EN 14429 (austenitic stainless steels) and EN 14462 (duplex stainless steel) was studied in a commercial LiBr solution (850 g/l LiBr solution containing chromate as inhibitor) at different temperatures (25, 50, 75 and 85 deg C) by electrochemical methods. Open circuit potentials shifted towards more active values as temperature increased, while corrosion potentials presented the opposite tendency. The most resistant alloys to general corrosion were EN 14429 and EN 14462 because they had the lowest corrosion current for all temperatures. In all the cases corrosion current increases with temperature. Pitting corrosion resistance is improved by the EN 14462, which presented the highest pitting potential, and the lowest passivation current for the whole range of temperatures studied. The duplex alloy also presents the worst repassivation behavior (in terms of the narrowest difference between corrosion potential and pitting potential); it does not repassivate from 50 deg C

  2. Critical pitting temperature for Type 254 SMO stainless steel in chloride solutions

    International Nuclear Information System (INIS)

    Abd El Meguid, E.A.; Abd El Latif, A.A.

    2007-01-01

    The variation with time of the open circuit potential of high molybdenum containing stainless steel (Type 254 SMO) was measured in 4% sodium chloride solution in the temperatures range 30-100 deg. C. The plot of steady state potentials as function of temperature showed an inflection at 50 deg. C, attributed to the decrease of oxygen solubility in test solution above 50 deg. C. Potentiodynamic cycling anodic polarization technique was used to determine the critical pitting potential (E pit ) and the critical protection potential (E prot ) of the steel in 4-30% NaCl solutions at temperatures between 30 and 100 deg. C. By plotting the two values versus solution temperature, the corresponding critical pitting (CPT) and the critical protection (CPrT) temperatures were determined. Both parameters decreased with increasing chloride content. Above the CPT, E pit and E prot decreased linearly with log[Cl - ]. The addition of bromide ions to the solution shifted both E pit and E prot towards positive values. In 4% NaCl, E pit increased linearly with pH in the range 1-10. The combined effect of chloride ion concentration and pH on the morphology of the pits was examined by scanning electron microscopy (SEM) following potentiodynamic cycling anodic polarization

  3. Volumetric and viscometric studies of glucose in binary aqueous solutions of urea at different temperatures

    International Nuclear Information System (INIS)

    Samanta, T.; Saharay, S.K.

    2010-01-01

    Densities and viscosities of glucose in (1.0, 2.5, and 5.0) mass% aqueous urea solutions have been measured at T = (298.15, 303.15, 308.15, and 313.15) K, respectively. Apparent molar volumes, limiting partial molar volume, and relative viscosity have been obtained from the density and viscosity results. Limiting partial molar expansibilities have also been calculated from the temperature dependence of limiting partial molar volumes. The viscosity data have been analyzed by using the modified Jones-Dole equation. The results are used to establish the nature of solute-solute and solute-solvent interactions. Transition state treatment of the relative viscosity was also used for the calculation of activation parameters of viscous flow. Pour findings show that the solute acts as a water structure former and provides strong solute-solvent interaction.

  4. Volumetric and viscometric studies of urea in binary aqueous solutions of glucose at different temperatures

    International Nuclear Information System (INIS)

    Samanta, T.; Ray, A.

    2010-01-01

    Densities and viscosities of urea in (1.0, 2.5, and 5.0) mass% of aqueous glucose solutions have been measured at T = (298.15, 303.15, 308.15, and 313.15) K, respectively. Apparent molar volumes, limiting partial molar volume, and relative viscosity have been obtained from the density and viscosity data. Limiting partial molar expansibilities have also been calculated from the temperature dependence of limiting partial molar volumes. The viscosity data has been analyzed using the Jones-Dole equation. The results are used to establish the nature of solute-solute and solute-solvent interactions. The activation parameters of viscous flow have also been calculated on the basis of transition state treatment of the relative viscosity. Result shows that the solute acts as water structure breaker and posses' weak solute-solvent interaction.

  5. Glass Transition Temperature of Saccharide Aqueous Solutions Estimated with the Free Volume/Percolation Model.

    Science.gov (United States)

    Constantin, Julian Gelman; Schneider, Matthias; Corti, Horacio R

    2016-06-09

    The glass transition temperature of trehalose, sucrose, glucose, and fructose aqueous solutions has been predicted as a function of the water content by using the free volume/percolation model (FVPM). This model only requires the molar volume of water in the liquid and supercooled regimes, the molar volumes of the hypothetical pure liquid sugars at temperatures below their pure glass transition temperatures, and the molar volumes of the mixtures at the glass transition temperature. The model is simplified by assuming that the excess thermal expansion coefficient is negligible for saccharide-water mixtures, and this ideal FVPM becomes identical to the Gordon-Taylor model. It was found that the behavior of the water molar volume in trehalose-water mixtures at low temperatures can be obtained by assuming that the FVPM holds for this mixture. The temperature dependence of the water molar volume in the supercooled region of interest seems to be compatible with the recent hypothesis on the existence of two structure of liquid water, being the high density liquid water the state of water in the sugar solutions. The idealized FVPM describes the measured glass transition temperature of sucrose, glucose, and fructose aqueous solutions, with much better accuracy than both the Gordon-Taylor model based on an empirical kGT constant dependent on the saccharide glass transition temperature and the Couchman-Karasz model using experimental heat capacity changes of the components at the glass transition temperature. Thus, FVPM seems to be an excellent tool to predict the glass transition temperature of other aqueous saccharides and polyols solutions by resorting to volumetric information easily available.

  6. Zirconium-cerin solid solutions: thermodynamic model and thermal stability at high temperature; Solutions solides de zirconium dans la cerine: modele thermodynamique et stabilite thermique a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Janvier, C.

    1998-04-02

    The oxides-gaseous dioxygen equilibria and the textural thermal stability of six zirconium-cerin solutions Ce{sub 1-x}Zr{sub x}O{sub 2} (0solutions and the gaseous oxygen by thermal gravimetric analysis at 600 degrees Celsius has shown that these solutions have not a ideal behaviour. A thermodynamic model where the point defects of solutions are included describe them the best. It becomes then possible to know the variations of the concentrations of the point defects in terms of temperature, oxygen pressure and zirconium concentration. A kinetic study (by calcination at 950 degrees Celsius of the solid solutions) of the specific surface area decrease has revealed a minima (0

  7. Spectroscopic investigation of solutions temperature effect on structure of americium(3) complexes with ethylenediaminetetraacetate and hydroxyethylethylenediaminetriacetate

    International Nuclear Information System (INIS)

    Nikitenko, S.I.; Martynenko, L.I.; Pechurova, N.I.

    1985-01-01

    Temperature dependence of absorption band intensity in spectra of solutions AmA - and AmX, where A 4- - ethylenediaminetetraacetate, X 3- - hydroxyethyl ethylenediaminetriacetate, has been studied spectrophotometrically. It is detected, that with the increase in solution temperature in the range 25-86 deg C a redistribution of absorption band intensities in AmA - X and AmX spectra is observed. Spectrum of Am 3+ never varies in the studied temperature range. It is assumed, that the observed phenomenon is explained by the change in the structure of Am 3+ complexonates during solution heating. Values of ΔH of the processes of internal coordination sphere rebuilding are calculated: 3.3+-0.9 (AmA - ), 2.2+-0.8 (AmX) kJ/mol

  8. High performance solution processed zirconium oxide gate dielectric appropriate for low temperature device application

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, Musarrat; Nguyen, Manh-Cuong; Kim, Hyojin; You, Seung-Won; Jeon, Yoon-Seok; Tong, Duc-Tai; Lee, Dong-Hwi; Jeong, Jae Kyeong; Choi, Rino, E-mail: rino.choi@inha.ac.kr

    2015-08-31

    This paper reports a solution processed electrical device with zirconium oxide gate dielectric that was fabricated at a low enough temperature appropriate for flexible electronics. Both inorganic dielectric and channel materials were synthesized in the same organic solvent. The dielectric constant achieved was 13 at 250 °C with a reasonably low leakage current. The bottom gate transistor devices showed the highest mobility of 75 cm{sup 2}/V s. The device is operated at low voltage with high-k dielectric with excellent transconductance and low threshold voltage. Overall, the results highlight the potential of low temperature solution based deposition in fabricating more complicated circuits for a range of applications. - Highlights: • We develop a low temperature inorganic dielectric deposition process. • We fabricate oxide semiconductor channel devices using all-solution processes. • Same solvent is used for dielectric and oxide semiconductor deposition.

  9. Stress Corrosion Cracking of Zircaloy-4 in Halide Solutions: Effect of Temperature

    Directory of Open Access Journals (Sweden)

    Farina S.B.

    2002-01-01

    Full Text Available Zircaloy-4 was found to be susceptible to stress corrosion cracking in 1 M NaCl, 1 M KBr and 1 M KI aqueous solutions at potentials above the pitting potential. In all the solutions tested crack propagation was initially intergranular and then changed to transgranular. The effect of strain rate and temperature on the SCC propagation was investigated. An increase in the strain rate was found to lead to an increase in the crack propagation rate. The crack propagation rate increases in the three solutions tested as the temperatures increases between 20 and 90 °C. The Surface-Mobility SCC mechanism accounts for the observation made in the present work, and the activation energy predicted in iodide solutions is similar to that found in the literature.

  10. Aroma volatility from aqueous sucrose solutions at low and subzero temperatures.

    Science.gov (United States)

    Covarrubias-Cervantes, Marco; Champion, Dominique; Debeaufort, Frédéric; Voilley, Andrée

    2004-11-17

    The gas-liquid partition coefficients of ethyl acetate and ethyl hexanoate have been measured in water and aqueous sucrose solutions from 25 to -10 degrees C by dynamic headspace. Experiments were carried out on sucrose solutions at temperatures where no ice formation was possible. Results showed that when sucrose concentration increased, aroma volatility increased except for ethyl hexanoate and in the highest sucrose concentration solution (57.5%). A quasi-linear temperature decrease on aroma volatility was observed in sucrose solutions from 25 to around 4 and 0 degrees C. Then, from 0 to -10 degrees C, aroma volatility did not decrease: ethyl acetate volatility remained constant but that of ethyl hexanoate increased. Enthalpy of vaporization and activity coefficients of the aroma compounds were calculated.

  11. Effect of solution treatment temperature and cooling rate on the mechanical properties of tungsten heavy alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Anjali, E-mail: anjalikumari1261@gmail.com; Prabhu, G.; Sankaranarayana, M.; Nandy, T.K.

    2017-03-14

    The present study investigates the effect of solution treatment temperature and cooling rate on mechanical properties of a tungsten heavy alloy (89.6W-6.2Ni-1.8Fe-2.4Co). In addition to water quenching, rapid argon quenching has been attempted in this study since it is a relatively cleaner process and it can be used in conjunction with vacuum treatment. Since in these alloys, there is a possibility of incomplete dissolution of intermetallics or segregation of impurities during heat treatment, which results in scatter in the mechanical properties, it was decided that the solution treatment temperature for both water and argon quenching would be varied from 1100 to 1250 °C in order to see its effect on the microstructure and mechanical properties. Solution treatment at varying temperatures followed by water quenching resulted in tensile strength ranging from 908 to 921 MPa and % elongation varied from 19% to 26%. On the other hand, the argon quenching heat treatment resulted in tensile strength in the range of 871–955 MPa and % elongation from 9% to 25%. No significant trend with respect to solution treatment temperature on tensile properties was seen in both argon and water quenched samples. % elongation to failure and impact values of water quenched specimens were better than those of argon quenched specimens for a given solution treatment temperature. The impact values appeared to improve with increasing solution treatment temperature in water quenched condition. The properties were correlated with underlying microstructure and fractographs of the failed specimens. The study showed the argon quenching may not be appropriate for the heat treatment of heavy alloys since it results in inferior mechanical properties as compared to water quenching.

  12. Global weak solutions for coupled transport processes in concrete walls at high temperatures

    OpenAIRE

    Beneš, Michal; Štefan, Radek

    2012-01-01

    We consider an initial-boundary value problem for a fully nonlinear coupled parabolic system with nonlinear boundary conditions modelling hygro-thermal behavior of concrete at high temperatures. We prove a global existence of a weak solution to this system on an arbitrary time interval. The main result is proved by an approximation procedure. This consists in proving the existence of solutions to mollified problems using the Leray-Schauder theorem, for which a priori estimates are obtained. T...

  13. Incoloy 800 anodic behavior in sulfate and chloride solutions at high temperature

    International Nuclear Information System (INIS)

    Lafont, C.; Alvarez, M.G.

    1992-01-01

    The anodic behavior and pitting corrosion resistance of Incoloy 800 in concentrated aqueous chloride and sulphate solutions has been studied by means of electrochemical techniques. The effect of different environmental variables, such as temperature (in the 100 0 C to 280 0 C range) and sulphate ion concentration (0.02 M to 2 M), was evaluated. In another set of experiments, the influence of sulphate ions additions on the pitting resistance and pitting morphology of Incoloy 800 in chloride solutions at high temperature was also examined. (author)

  14. Storage Duration and Temperature Effects of Strychnos potatorum Stock Solutions on its Coagulation Efficiency

    Directory of Open Access Journals (Sweden)

    Rekha R Warrier

    2014-12-01

    Full Text Available This study presents the effects of storage duration and temperature of Strychnos potatorum stock solution on its coagulation efficiency. Coagulation efficiency of the seed extracts on water samples depended on the initial turbidity of the water sample. The stock solutions could clarify only highly turbid solutions. The optimum dosage of the stock solutions was 5% and optimal time required was 50 minutes. S. potatorum stock solutions, which were kept at room temperature (28 °C, had a shelf life of only five days and were able to remove turbidity from high and low turbidity water samples and no coagulation activity was observed for medium turbidity. The highest turbidity removals were observed for stock solutions, which were kept for three days. For stock solutions which were stored in refrigerator, shelf life was extended upto seven days, and the turbidity removal efficiencies improved from 45.9 to 63.8 for low and 43.7 to 64.9 % for high turbidity water samples, respectively.

  15. A new variable temperature solution-solid interface scanning tunneling microscope.

    Science.gov (United States)

    Jahanbekam, Abdolreza; Mazur, Ursula; Hipps, K W

    2014-10-01

    We present a new solution-solid (SS) interface scanning tunneling microscope design that enables imaging at high temperatures with low thermal drift and with volatile solvents. In this new design, distinct from the conventional designs, the entire microscope is surrounded in a controlled-temperature and controlled-atmosphere chamber. This allows users to take measurements at high temperatures while minimizing thermal drift. By incorporating an open solution reservoir in the chamber, solvent evaporation from the sample is minimized; allowing users to use volatile solvents for temperature dependent studies at high temperatures. The new design enables the user to image at the SS interface with some volatile solvents for long periods of time (>24 h). An increase in the nonlinearity of the piezoelectric scanner in the lateral direction as a function of temperature is addressed. A temperature dependent study of cobalt(II) octaethylporphyrin (CoOEP) at the toluene/Au(111) interface has been performed with this instrument. It is demonstrated that the lattice parameters remain constant within experimental error from 24 °C to 75 °C. Similar quality images were obtained over the entire temperature range. We report the unit cell of CoOEP at the toluene/Au(111) interface (based on two molecules per unit cell) to be A = (1.36 ± 0.04) nm, B = (2.51 ± 0.04) nm, and α = 97° ± 2°.

  16. Thermoresponsive behavior of chitosan-g-N-isopropylacrylamide copolymer solutions.

    Science.gov (United States)

    Recillas, Maricarmen; Silva, Luisa L; Peniche, Carlos; Goycoolea, Francisco M; Rinaudo, Marguerite; Argüelles-Monal, Waldo M

    2009-06-08

    Chitosan-g-N-isopropylacrylamide (NIPAm) water-soluble copolymers were synthesized and characterized by FTIR and (1)H NMR spectroscopies combined with conductometric and potentiometric titrations. Their thermoresponsive, fully reversible, behavior in aqueous solutions was characterized by means of microcalorimetry and rheology. During heating of copolymer solutions there is a well-known endothermic effect, which coincides with a marked increase in G' and a moderate decrement in G'' due to the formation of a hydrophobic network at the expense of the net amount of sol fraction. It was also found that a straight dependence between the values of G' above the LCST and the enthalpies associated with the transition reflecting that the connectivity in the gel network is governed by the net number of formed enthalpic-hydrophobic driven-junctions. Both the LCST and the enthalpy change vary with the ionic strength of copolymer solutions, but no dependence was found with the neutralization of the polyelectrolyte chain.

  17. The effect of temperature on radiolysis of iodide ion diluted aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gorbovitskaya, T; Tiliks, J [Latvia Univ., Lab. of Radiation Chemistry, Riga (Latvia)

    1996-12-01

    To investigate the radiolysis of iodine containing aqueous solutions a flow type facility (ITF) has a possibility to irradiate aqueous solutions in the steel vessel with {sup 60}Co {gamma}-rays and continuously (on line) to analyze the products of radiolysis both in liquid and in gaseous phases. By means of ITF the formation of I{sub ox} (I{sub 2} + I{sub 3}{sup -} + HOI), IO{sub 3}{sup -}, H{sub 2}O{sub 2} was studied in 10{sup -5} - 10{sup -3} mol/dm{sup 3} CsI aqueous solutions by their radiolysis at dose rate 4.5 kGv/h for six hours in region of temperatures from 313 to 404 K. Some experiments in glass ampoules were also performed. The steady-state concentrations of I{sub ox} and IO{sub 3}{sup -} decreased with increasing temperature as linear function of inverted temperature. The effect decreased with decreasing concentration of iodide ion. As the result, at high temperatures (T{>=}380 K) the steady-state concentration of I{sub ox} does not depend essentially on the iodide ion initial concentration. Molecular iodine (I{sub 2}) released from the solution was the main radiolysis product in gaseous phase. Its steady-state concentration increased with increasing temperature because of iodine solubility in the water and decreased at the same time because the radiolytic iodine concentrations decreased. Therefore the most volatility of irradiated 10{sup -3} and 10{sup -4}M CsI solutions was observed at the temperature about 350 K. The volatility of 10{sup -5}M solutions gradually decreased with increasing temperature. The experimental data were explained on the base of the hypothesis that the reaction between I{sub 2} and radiolytic H{sub 2}O{sub 2} was the limit one determining the temperature dependence of I{sub ox} and IO{sub 3}{sup -}steady-state concentrations. Its activation energy was estimated to be 27,5 kcal.mol{sup -1}. The temperature dependence for reaction (IO{sup -} + H{sub 2}O{sub 2}) was also estimated. (author) 8 figs., 1 tab., 17 refs.

  18. The effect of temperature on radiolysis of iodide ion diluted aqueous solutions

    International Nuclear Information System (INIS)

    Gorbovitskaya, T.; Tiliks, J.

    1996-01-01

    In order to investigate the radiolysis of iodine containing aqueous solutions a flow type facility - Iodine Thermoradiation Facility (ITF) has been designed. It has a possibility to irradiate aqueous solutions in the steel vessel with 60 Co γ-rays and continuously (on line) to analyze the products of radiolysis both in liquid and in gaseous phases. By means of ITF the formation of I ox (I 2 + I 3 - + HOI), IO 3 - , H 2 O 2 was studied in 10 -5 - 10 -3 mol/dm 3 CsI aqueous solutions by their radiolysis at dose rate 4.5 kGv/h for six hours in region of temperatures from 313 to 404 K. Under similar conditions, some experiments in glass ampoules were also performed. The steady-state concentrations of I ox and IO 3 - decreased with increasing temperature as linear function of inverted temperature. The effect decreased with decreasing concentration of iodide ion. As the result, at high temperatures (T≥380 K) the steady-state concentration of I ox does not depend essentially on the iodide ion initial concentration. Molecular iodine (I 2 ) released from the solution was the main radiolysis product in gaseous phase. Its steady-state concentration increased with increasing temperature because of iodine solubility in the water and decreased at the same time because the radiolytic iodine concentrations decreased. Therefore the most volatility of irradiated 10 -3 and 10 -4 M CsI solutions was observed at the temperature about 350 K. The volatility of 10 -5 M solutions gradually decreased with increasing temperature. The experimental data were explained on the base of the hypothesis that the reaction between I 2 and radiolytic H 2 O 2 was the limit one determining the temperature dependence of I ox and IO 3 - steady-state concentrations. Its activation energy was estimated to be 27,5 kcal.mol -1 . The temperature dependence for reaction (IO - + H 2 O 2 ) was also estimated. (author) 8 figs., 1 tab., 17 refs

  19. Temperature influence on corrosion rate of armco iron in acid solutions

    International Nuclear Information System (INIS)

    Perboni, G.; Rocchini, G.

    1986-01-01

    An experimental study of the behaviour of Armco iron and several steels in acid solutions (HCl, H 2 SO 4 , H 3 PO 4 ) has been undertaken to determine the temperature effect on dissolution rate. The test temperatures were 30, 45, 60, 75 and 90 deg C. The activation heat was determined by application of the Arrhenius law from colorimetric and electrochemical data. Investigation results obtained by both methods were represented diagrammatically and showed a good agreement, though the discrepancy in the data increased with test temperature

  20. The relation between temperature and concentration gradients in superfluid sup 3 He- sup 4 He solutions

    CERN Document Server

    Zadorozhko, A A; Rudavskij, E Y; Chagovets, V K; Sheshin, G A

    2003-01-01

    The temperature and concentration gradients nabla T and nabla x in a superfluid sup 3 He- sup 4 He mixture with an initial concentration 9,8 % of sup 3 He are measured in a temperature range 70-500 mK. The gradients are produced by a steady thermal flow with heating from below. It is shown that the value of nabla x/nabla T observed in the experiment is in good agreement with the theoretical model derived from the temperature and concentration dependences of osmotic pressure. The experimental data permitted us to obtain a thermal diffusion ratio of the solution responsible for the thermal diffusion coefficient.

  1. Enhanced field emission of ZnO nanoneedle arrays via solution etching at room temperature

    DEFF Research Database (Denmark)

    Ma, Huanming; Qin, Zhiwei; Wang, Zaide

    2017-01-01

    ZnO nanoneedle arrays (ZnO nns) were synthesized by a facile two-step solution-phase method based on the etching of pre-synthesized ZnO nanowire arrays (ZnO nws) with flat ends at room temperature. Field emission measurement results showed that the turn-on electronic fields of ZnO nns and nws wer...

  2. Estimating the Soil Temperature Profile from a single Depth Observation: A simple Empirical Heatflow Solution

    NARCIS (Netherlands)

    Holmes, T.R.H.; Owe, M.; de Jeu, R.A.M.; Kooi, H.

    2008-01-01

    Two field data sets are used to model near-surface soil temperature profiles in a bare soil. It is shown that the commonly used solutions to the heat flow equations by Van Wijk perform well when applied at deeper soil layers, but result in large errors when applied to near surface layers, where more

  3. Effect of temperature and salting-out agents on the sorption of nitrophenols from aqueous solutions

    Directory of Open Access Journals (Sweden)

    E. V. Churilina

    2013-01-01

    Full Text Available Sorption of nitrophenols from aqueous media by сrosslinked N-vinylpyrrolidone-based polymer in static conditions are studied depending on the pH of the solution and the nature of the nitrophenols. It has been established that a temperature and the introduction of salting-out agents influence on the sorption of nitrophenols.

  4. Room temperature synthesis of protonated layered titanate sheets using peroxo titanium carbonate complex solution.

    Science.gov (United States)

    Sutradhar, Narottam; Sinhamahapatra, Apurba; Pahari, Sandip Kumar; Bajaj, Hari C; Panda, Asit Baran

    2011-07-21

    We report the synthesis of peroxo titanium carbonate complex solution as a novel water-soluble precursor for the direct synthesis of layered protonated titanate at room temperature. The synthesized titanates showed excellent removal capacity for Pb(2+) and methylene blue. Based on experimental observations, a probable mechanism for the formation of protonated layered dititanate sheets is also discussed.

  5. OSMOTIC COEFFICIENTS, SOLUBILITIES, AND DELIQUESCENCE RELATIONS IN MIXED AQUEOUS SALT SOLUTIONS AT ELEVATED TEMPERATURE

    International Nuclear Information System (INIS)

    M.S. Gruszkiewicz; D.A. Palmer

    2006-01-01

    While thermodynamic properties of pure aqueous electrolytes are relatively well known at ambient temperature, there are far fewer data for binary systems extending to elevated temperatures and high concentrations. There is no general theoretically sound basis for prediction of the temperature dependence of ionic activities, and consequently temperature extrapolations based on ambient temperature data and empirical equations are uncertain and require empirical verification. Thermodynamic properties of mixed brines in a wide range of concentrations would enhance the understanding and precise modeling of the effects of deliquescence of initially dry solids in humid air in geological environments and in modeling the composition of waters during heating, cooling, evaporation or condensation processes. These conditions are of interest in the analysis of waters on metal surfaces at the proposed radioactive waste repository at Yucca Mountain, Nevada. The results obtained in this project will be useful for modeling the long-term evolution of the chemical environment, and this in turn is useful for the analysis of the corrosion of waste packages. In particular, there are few reliable experimental data available on the relationship between relative humidity and composition that reveals the eutonic points of the mixtures and the mixture deliquescence RH. The deliquescence RH for multicomponent mixtures is lower than that of pure component or binary solutions, but is not easy to predict quantitatively since the solutions are highly nonideal. In this work we used the ORNL low-temperature and high-temperature isopiestic facilities, capable of precise measurements of vapor pressure between ambient temperature and 250 C for determination of not only osmotic coefficients, but also solubilities and deliquescence points of aqueous mixed solutions in a range of temperatures. In addition to standard solutions of CaCl 2 , LiCl, and NaCl used as references, precise direct

  6. Correction of MHS Viscosimetric Constants upon Numerical Simulation of Temperature Induced Degradation Kinetic of Chitosan Solutions

    Directory of Open Access Journals (Sweden)

    Vincenzo Maria De Benedictis

    2016-05-01

    Full Text Available The Mark–Houwink–Sakurada (MHS equation allows for estimation of rheological properties, if the molecular weight is known along with good understanding of the polymer conformation. The intrinsic viscosity of a polymer solution is related to the polymer molecular weight according to the MHS equation, where the value of the constants is related to the specific solvent and its concentration. However, MHS constants do not account for other characteristics of the polymeric solutions, i.e., Deacetilation Degree (DD when the solute is chitosan. In this paper, the degradation of chitosan in different acidic environments by thermal treatment is addressed. In particular, two different solutions are investigated (used as solvent acetic or hydrochloric acid with different concentrations used for the preparation of chitosan solutions. The samples were treated at different temperatures (4, 30, and 80 °C and time points (3, 6 and 24 h. Rheological, Gel Permeation Chromatography (GPC, Fourier Transform Infrared Spectroscopy (FT-IR, Differential Scanning Calorimetry (DSC and Thermal Gravimetric Analyses (TGA were performed in order to assess the degradation rate of the polymer backbones. Measured values of molecular weight have been integrated in the simulation of the batch degradation of chitosan solutions for evaluating MHS coefficients to be compared with their corresponding experimental values. Evaluating the relationship between the different parameters used in the preparation of chitosan solutions (e.g., temperature, time, acid type and concentration, and their contribution to the degradation of chitosan backbone, it is important to have a mathematical frame that could account for phenomena involved in polymer degradation that go beyond the solvent-solute combination. Therefore, the goal of the present work is to propose an integration of MHS coefficients for chitosan solutions that contemplate a deacetylation degree for chitosan systems or a more

  7. Effect of different ions on the anodic behaviour of alloy 800 chloride solutions at high temperature

    International Nuclear Information System (INIS)

    Lafont, C.J.; Alvarez, M.G.

    1993-01-01

    The anodic behaviour and passivity breakdown of alloy 800 in sodium bicarbonate and sodium phosphate aqueous solutions were studied in the temperature range from 100 degrees C to 280 degrees C by means of electrochemical techniques. The effect of phosphate or bicarbonate additions on the pitting susceptibility and pitting morphology of the alloy in chloride solutions was also examined. Experiments were performed in the following solutions: 0.1M NaHCO 3 , at 100 degrees C, 200 degrees C, 280 degrees C; 0.06M NaH 2 PO 4 + 0.04M Na 2 HPO 4 , at 100 degrees C, 200 degrees C and 280 degrees C, and 0.1M NaCl with different additions of bicarbonate ion (0.02M, 0.05M and 0.1M) and phosphate ion (0.01M, 0.05M and 0.1M) at 100 degrees C and 280 degrees C. The anodic polarization curves of alloy 800 in deaerated 0.1M NaHCO 3 and 0.06M NaH 2 PO 4 + 0.04M Na 2 HPO 4 solutions exhibited a similar shape at all the tested temperatures. No localized or generalized corrosion was detected on the metallic surface after polarization. The results obtained in chloride plus bicarbonate and chloride plus phosphate mixtures showed that the pitting potential of alloy 800 in chloride solutions was increased by the presence of bicarbonate or phosphate ions. In those solutions where the inhibitor concentration in the mixture is equal or higher than the chloride concentration , the behaviour of the alloy is similar to the one observed in the absence of chlorides. Changes in pitting morphology were found in phosphate containing solutions, while the pits found in bicarbonate containing solutions were similar to those formed in pure chloride solutions. (author). 3 refs., 4 figs

  8. Required developments towards ultra high pressure and temperature subsea tree system solutions

    Energy Technology Data Exchange (ETDEWEB)

    Queseth, Per-Olaf

    2010-07-01

    For the subsea High Pressure High Temperature oil and gas production systems, the primary challenge is to provide good, reliable solutions for HPHT reservoir exploitation based on an overview of parameters for already discovered potential fields. The paper will present a resume of Aker Solutions' previous development in this area exemplified with experiences from testing and operator observations during production start of HPHT fields in the North Sea. Further improvements are required to comply with the extreme pressures and temperatures sought to overcome. 'The Devil is in the details' is a very relevant proverb. A program to qualify subsea production X-mas trees for Ultra HPHT use will be presented with highlight on sealing systems, feed-through solutions and materials as well as impact on interfacing systems. Preliminary and intermediate analytical and test results will be presented and remaining activities summarised. (Author)

  9. Passivation behavior of SUS 304 stainless steel in neutral solutions at elevated temperature

    International Nuclear Information System (INIS)

    Tanno, Kazuo; Kato, Koji; Ohnaka, Noriyuki; Okajima, Yoshiaki; Minato, Akira.

    1981-01-01

    Cyclic voltammograms of SUS 304 stainless steel in various neutral solutions such as Na 2 SO 4 at high temperature were measured, as a successive study to previous report in which effects of temperature and pH on polarization behavior of stainless steel were studied. In this measurement Ag/AgCl reference electrode and platinum counter electrode were used in a static autoclave lined with inconel. Passive films formed in various conditions were analysed by electron diffraction and Auger spectroscopy. Results obtained were compared with anodic behavior of iron, chromium and nickel and with thermodynamical stabilities of their compounds. The main results are summarized as follows. (1) Stainless steel shows such electrochemical behavior as active dissolution, passivation and transpassivation in a deaerated neutral solution at 250 0 C after fully reductive treatment of the specimen. In air-saturated solution, the peak of active dissolution is not observed. In the passive range there are intermediate oxidation and reduction peaks, and it is assumed that dissolved ionic species are oxidized to form oxide of spinel type and higher oxidized state successively at these peaks. (2) Electrochemical behavior of specimens in 0.1 M sulfate, -phosphate and -carbonate solutions are almost the same and rather thick films form in these solutions. On the other hand, specimens are easy to passivate in borate and -nitrate solution, and their passive films are thin. (author)

  10. Fatigue behavior of alloy 600 in sodium chloride solution at room temperature

    International Nuclear Information System (INIS)

    Ho, J.-T.; Yu, G.-P.

    2004-01-01

    Fatigue crack growth (FCG) rates of mill annealed Alloy 600 in NaCI solution were studied by a fracture mechanics test method. Compact tension (CT) specimens were tested under load control with a sinusoidal wave form, in accordance with ASTM specification E647-83, to investigate the effects of environment, load frequency (f), load ratio (R=Pmin/Pmax). The FCG rates of Alloy 600, R=0.1, f=1Hz, were quite similar in air, distilled water, and NaCI (0.6 M, 0.1 M, and 0.001 M) solution at room temperature. Environmental enhancement effect on the FCG rate of Alloy 600 was not significant in NaCI solution. Variations of the load frequency (0.03Hz-3Hz) did not influence the FCG rates of Alloy 600 significantly in air and 0.1 M NaCI solution. The FCG rates of Alloy 600 in air and 0.1 M NaCI solution increased with increasing the load ratio. Compared with the corrosion effects, test results showed that the mechanical effects dominated on the FCG rates of Alloy 600 in chloride solution at room temperature. The SEM fractographs showed that significant striations and transgranular fracture modes were observed on tested specimens. (author)

  11. Solution of the neutron point kinetics equations with temperature feedback effects applying the polynomial approach method

    Energy Technology Data Exchange (ETDEWEB)

    Tumelero, Fernanda, E-mail: fernanda.tumelero@yahoo.com.br [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica; Petersen, Claudio Z.; Goncalves, Glenio A.; Lazzari, Luana, E-mail: claudiopeteren@yahoo.com.br, E-mail: gleniogoncalves@yahoo.com.br, E-mail: luana-lazzari@hotmail.com [Universidade Federal de Pelotas (DME/UFPEL), Capao do Leao, RS (Brazil). Instituto de Fisica e Matematica

    2015-07-01

    In this work, we present a solution of the Neutron Point Kinetics Equations with temperature feedback effects applying the Polynomial Approach Method. For the solution, we consider one and six groups of delayed neutrons precursors with temperature feedback effects and constant reactivity. The main idea is to expand the neutron density, delayed neutron precursors and temperature as a power series considering the reactivity as an arbitrary function of the time in a relatively short time interval around an ordinary point. In the first interval one applies the initial conditions of the problem and the analytical continuation is used to determine the solutions of the next intervals. With the application of the Polynomial Approximation Method it is possible to overcome the stiffness problem of the equations. In such a way, one varies the time step size of the Polynomial Approach Method and performs an analysis about the precision and computational time. Moreover, we compare the method with different types of approaches (linear, quadratic and cubic) of the power series. The answer of neutron density and temperature obtained by numerical simulations with linear approximation are compared with results in the literature. (author)

  12. Solution of the neutron point kinetics equations with temperature feedback effects applying the polynomial approach method

    International Nuclear Information System (INIS)

    Tumelero, Fernanda; Petersen, Claudio Z.; Goncalves, Glenio A.; Lazzari, Luana

    2015-01-01

    In this work, we present a solution of the Neutron Point Kinetics Equations with temperature feedback effects applying the Polynomial Approach Method. For the solution, we consider one and six groups of delayed neutrons precursors with temperature feedback effects and constant reactivity. The main idea is to expand the neutron density, delayed neutron precursors and temperature as a power series considering the reactivity as an arbitrary function of the time in a relatively short time interval around an ordinary point. In the first interval one applies the initial conditions of the problem and the analytical continuation is used to determine the solutions of the next intervals. With the application of the Polynomial Approximation Method it is possible to overcome the stiffness problem of the equations. In such a way, one varies the time step size of the Polynomial Approach Method and performs an analysis about the precision and computational time. Moreover, we compare the method with different types of approaches (linear, quadratic and cubic) of the power series. The answer of neutron density and temperature obtained by numerical simulations with linear approximation are compared with results in the literature. (author)

  13. Effect of dope solution temperature on the membrane structure and membrane distillation performance

    Science.gov (United States)

    Nawi, N. I. M.; Bilad, M. R.; Nordin, N. A. H. M.

    2018-04-01

    Membrane distillation (MD) is a non-isothermal process applicable to purify water using hydrophobic membrane. Membrane in MD is hydrophobic, permeable to water vapor but repels liquid water. MD membrane is expected to pose high flux, high fouling and scaling resistances and most importantly high wetting resistance. This study develops flat-sheet polyvinylidene fluoride (PVDF) membrane by exploring both liquid-liquid and liquid-solid phase inversion technique largely to improve its wetting resistance and flux performance. We hypothesize that temperature of dope solution play roles in solid-liquid separation during membrane formation and an optimum balance between liquid-liquid and liquid-solid (crystallization) separation leads to highly performance PVDF membrane. Findings obtained from differential scanning calorimeter test show that increasing dope solution temperature reduces degree of PVDF crystallinity and suppresses formation of crystalline structure. The morphological images of the resulting membranes show that at elevated dope solution temperature (40, 60, 80 and 100°C), the spherulite-like structures are formed across the thickness of membranes ascribed from due to different type of crystals. The performance of direct-contact MD shows that the obtained flux of the optimum dope temperature (60°C) of 10.8 L/m2h is comparable to commercial PTFE-based MD membrane.

  14. High temperature thermodynamics of solutions of oxygen in zirconium and hafnium

    International Nuclear Information System (INIS)

    Boureau, G.; Gerdanian, P.

    1984-01-01

    The Tian-Calvet microcalorimetric method has been applied to the determination at 1323 Kelvin of ΔH(O 2 ), the partial molar enthalpy of mixing of oxygen in zirconium and in hafnium. No measurable departure from Henry's law has been found for dilute solutions (ratio oxygen over metal smaller than 0.1). For concentrated solutions repulsive interactions are found in agreement with the existence of ordered structures at lower temperatures. The domain of homogeneity of zirconium has been found larger than previously assumed. (author)

  15. Exploring Poly(ethylene glycol-Polyzwitterion Diblock Copolymers as Biocompatible Smart Macrosurfactants Featuring UCST-Phase Behavior in Normal Saline Solution

    Directory of Open Access Journals (Sweden)

    Noverra M. Nizardo

    2018-03-01

    Full Text Available Nonionic-zwitterionic diblock copolymers are designed to feature a coil-to-globule collapse transition with an upper critical solution temperature (UCST in aqueous media, including physiological saline solution. The block copolymers that combine presumably highly biocompatible blocks are synthesized by chain extension of a poly(ethylene glycol (PEG macroinitiator via atom transfer radical polymerization (ATRP of sulfobetaine and sulfabetaine methacrylates. Their thermoresponsive behavior is studied by variable temperature turbidimetry and 1H NMR spectroscopy. While the polymers with polysulfobetaine blocks exhibit phase transitions in the physiologically interesting window of 30–50 °C only in pure aqueous solution, the polymers bearing polysulfabetaine blocks enabled phase transitions only in physiological saline solution. By copolymerizing a pair of structurally closely related sulfo- and sulfabetaine monomers, thermoresponsive behavior can be implemented in aqueous solutions of both low and high salinity. Surprisingly, the presence of the PEG blocks can affect the UCST-transitions of the polyzwitterions notably. In specific cases, this results in “schizophrenic” thermoresponsive behavior displaying simultaneously an UCST and an LCST (lower critical solution temperature transition. Exploratory experiments on the UCST-transition triggered the encapsulation and release of various solvatochromic fluorescent dyes as model “cargos” failed, apparently due to the poor affinity even of charged organic compounds to the collapsed state of the polyzwitterions.

  16. Behaviour of aqueous sulfamethizole solution and temperature effects in cold plasma oxidation treatment.

    Science.gov (United States)

    Sokolov, Alexander; Louhi-Kultanen, Marjatta

    2018-06-07

    The increase in volume and variety of pharmaceuticals found in natural water bodies has become an increasingly serious environmental problem. The implementation of cold plasma technology, specifically gas-phase pulsed corona discharge (PCD), for sulfamethizole abatement was studied in the present work. It was observed that sulfamethizole is easily oxidized by PCD. The flow rate and pH of the solution have no significant effect on the oxidation. Treatment at low pulse repetition frequency is preferable from the energy efficiency point of view but is more time-consuming. The maximum energy efficiency was around 120 g/kWh at half-life and around 50 g/kWh at the end of the treatment. Increasing the solution temperature from room temperature to 50 °C led to a significant reaction retardation of the process and decrease in energy efficiency. The pseudo-first order reaction rate constant (k 1 ) grows with increase in pulse repetition frequency and does not depend on pH. By contrast, decreasing frequency leads to a reduction of the second order reaction rate constant (k 2 ). At elevated temperature of 50 °C, the k 1 , k 2 values decrease 2 and 2.9 times at 50 pps and 500 pps respectively. Lower temperature of 10 °C had no effect on oxidation efficiency compared with room temperature.

  17. Temperature and concentration calibration of aqueous polyvinylpyrrolidone (PVP solutions for isotropic diffusion MRI phantoms.

    Directory of Open Access Journals (Sweden)

    Friedrich Wagner

    Full Text Available To use the "apparent diffusion coefficient" (Dapp as a quantitative imaging parameter, well-suited test fluids are essential. In this study, the previously proposed aqueous solutions of polyvinylpyrrolidone (PVP were examined and temperature calibrations were obtained. For example, at a temperature of 20°C, Dapp ranged from 1.594 (95% CI: 1.593, 1.595 μm2/ms to 0.3326 (95% CI: 0. 3304, 0.3348 μm2/ms for PVP-concentrations ranging from 10% (w/w to 50% (w/w using K30 polymer lengths. The temperature dependence of Dapp was found to be so strong that a negligence seems not advisable. The temperature dependence is descriptively modelled by an exponential function exp(c2 (T - 20°C and the determined c2 values are reported, which can be used for temperature calibration. For example, we find the value 0.02952 K-1 for 30% (w/w PVP-concentration and K30 polymer length. In general, aqueous PVP solutions were found to be suitable to produce easily applicable and reliable Dapp-phantoms.

  18. Temperature-responsive PLLA/PNIPAM nanofibers for switchable release

    Energy Technology Data Exchange (ETDEWEB)

    Elashnikov, Roman; Slepička, Petr [Department of Solid State Engineering, University of Chemistry and Technology, Prague 166 28 (Czech Republic); Rimpelova, Silvie; Ulbrich, Pavel [Department of Biochemistry and Microbiology, University of Chemistry and Technology, 16628 Prague (Czech Republic); Švorčík, Vaclav [Department of Solid State Engineering, University of Chemistry and Technology, Prague 166 28 (Czech Republic); Lyutakov, Oleksiy, E-mail: lyutakoo@vscht.cz [Department of Solid State Engineering, University of Chemistry and Technology, Prague 166 28 (Czech Republic)

    2017-03-01

    Smart antimicrobial materials with on-demand drug release are highly desired for biomedical applications. Herein, we report about temperature-responsive poly(N-isopropylacrylamide) (PNIPAM) nanospheres doped with crystal violet (CV) and incorporated into the poly-L-lactide (PLLA) nanofibers. The nanofibers were prepared by electrospinning, using different initial polymers ratios. The morphology of the nanofibers and polymers distribution in the nanofibers were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The interaction between PNIPAM and PLLA in the nanofibers was studied by Fourier transform infrared spectroscopy (FTIR) and its effect on the PNIPAM phase transition was also investigated. It was shown that by the changing of the environmental temperature across the lower critical solution temperature (LCST) of PNIPAM, the switchable wettability and controlled CV release can be achieved. The temperature-dependent release kinetics of CV from polymer nanofibers was investigated by ultraviolet-visible spectroscopy (UV–Vis). The temperature-responsive release of antibacterial CV was also tested for triggering of antibacterial activity, which was examined on Staphylococcus epidermidis (S. epidermidis) and Escherichia coli (E. coli). Thus, the proposed material is promising value for controllable drug-release.

  19. Solution of Point Reactor Neutron Kinetics Equations with Temperature Feedback by Singularly Perturbed Method

    Directory of Open Access Journals (Sweden)

    Wenzhen Chen

    2013-01-01

    Full Text Available The singularly perturbed method (SPM is proposed to obtain the analytical solution for the delayed supercritical process of nuclear reactor with temperature feedback and small step reactivity inserted. The relation between the reactivity and time is derived. Also, the neutron density (or power and the average density of delayed neutron precursors as the function of reactivity are presented. The variations of neutron density (or power and temperature with time are calculated and plotted and compared with those by accurate solution and other analytical methods. It is shown that the results by the SPM are valid and accurate in the large range and the SPM is simpler than those in the previous literature.

  20. Solution-Mediated Annealing of Polymer Optical Fiber Bragg Gratings at Room Temperature

    DEFF Research Database (Denmark)

    Fasano, Andrea; Woyessa, Getinet; Janting, Jakob

    2017-01-01

    In this letter, we investigate the response of poly(methylmethacrylate) (PMMA) microstructured polymer optical fiber Bragg gratings (POFBGs) after immersion inmethanol/water solutions at room temperature. As the glass transition temperature of solution-equilibrated PMMA differs from the one...... of solvent-free PMMA, different concentrations of methanol and water lead to various degrees of frozen-in stress relaxation in the fiber. After solvent evaporation, we observe a permanent blue-shift in the grating resonance wavelength. The main contribution in the resonance wavelength shift arises from...... a permanent change in the size of the fiber. The results are compared with conventional annealing. The proposed methodology is cost-effective as it does not require a climate chamber. Furthermore, it enables an easy-to-control tuning of the resonance wavelength of POFBGs....

  1. Effect of Mn Content and Solution Annealing Temperature on the Corrosion Resistance of Stainless Steel Alloys

    Directory of Open Access Journals (Sweden)

    Ihsan-ul-Haq Toor

    2014-01-01

    Full Text Available The corrosion behavior of two specially designed austenitic stainless steels (SSs having different Nickel (Ni and Manganese (Mn contents was investigated. Prior to electrochemical tests, SS alloys were solution-annealed at two different temperatures, that is, at 1030°C for 2 h and 1050°C for 0.5 h. Potentiodynamic polarization (PD tests were carried out in chloride and acidic chloride, whereas linear polarization resistance (LPR and electrochemical impedance spectroscopy (EIS was performed in 0.5 M NaCl solution at room temperature. SEM/EDS investigations were carried out to study the microstructure and types of inclusions present in these alloys. Experimental results suggested that the alloy with highest Ni content and annealed at 1050°C/0.5 hr has the highest corrosion resistance.

  2. On-line monitoring of resistance of aqueous solutions at high temperature

    International Nuclear Information System (INIS)

    Hu Shilin; Zhang Pingzhu; Shang Weiguo

    1999-01-01

    The coulostatic measurement is a fast speed electrochemical test method. By this technology, analyzing Δ E(t)- T curves recorded under coulostatic perturbation, the solution resistance R l , resistance of coated film R f , capacity of coated film C f , Polarization resistance R p and double layer capacity C d are obtained. The resistance variety of 0.05N KCl is measured from room temperature up to 255 deg. C under saturation steam pressure. (author)

  3. LOW TEMPERATURE PROCESS FOR THE REMOVAL AND RECOVERY OF CHLORIDES AND NITRATES FROM AQUEOUS NITRATE SOLUTIONS

    Science.gov (United States)

    Savolainen, J.E.

    1963-01-29

    A method is described for reducing the chloride content of a solution derived from the dissolution of a stainless steel clad nuclear fuel element with an aqua regia dissolution medium. The solutlon is adjusted to a nitric acid concentration in the range 5 to 10 M and is countercurrently contacted at room temperature with a gaseous oxide of nitrogen selected from NO, NO/sub 2/, N/sub 2/ O/sub 3/, and N/sub 2/O/sub 4/. Chlo ride is recovered from the contacted solution as nitrosyl chloride. After reduction of the chloride content, the solution is then contacted with gaseous NO to reduce the nitric acid molarity to a desired level. (AEC)

  4. Tunable Temperature Response of a Thermochromic Photonic Gel Sensor Containing N-Isopropylacrylamide and 4-Acryloyilmorpholine

    Directory of Open Access Journals (Sweden)

    Hwanam Kye

    2017-06-01

    Full Text Available In this study, thermochromic photonic gels were fabricated using 2-hydroxyethyl methacrylate (HEMA as a hydrogel building block, and 4-Acryloyl morpholine (ACMO and N-isopropylacrylamide (NIPAAM as thermoresponsive monomers with different critical solution temperature behaviors. Rapid photopolymerization of opal-templated monomer mixtures of varying ACMO contents formed five individual thermochromic inverse opal photonic gels integrated on a single substrate. With temperature variation from 10 °C to 80 °C, the changes in reflective colors and reflectance spectra of the respective thermochromic gels were noted, and λpeak changes were plotted. Because NIPAAM exhibits a lower critical solution temperature (LCST at 33 °C, the NIPAAM-only gel showed a steep slope for dλpeak/dT below 40 °C, whereas the slope became flatter at high temperatures. As the ACMO content increased in the thermochromic gel, the curve of dλpeak/dT turned out to be gradual within the investigated temperature range, exhibiting the entire visible range of colors. The incorporation of ACMO in NIPAAM-based thermochromic gels therefore enabled a better control of color changes at a relatively high-temperature regime compared to a NIPAAM-only gel. In addition, ACMO-containing thermochromic gels exhibited a smaller hysteresis of λpeak for the heating and cooling cycle.

  5. Development of Temperature Control Solutions for Non-Instrumented Nucleic Acid Amplification Tests (NINAAT

    Directory of Open Access Journals (Sweden)

    Tamás Pardy

    2017-06-01

    Full Text Available Non-instrumented nucleic acid amplification tests (NINAAT are a novel paradigm in portable molecular diagnostics. They offer the high detection accuracy characteristic of nucleic acid amplification tests (NAAT in a self-contained device, without the need for any external instrumentation. These Point-of-Care tests typically employ a Lab-on-a-Chip for liquid handling functionality, and perform isothermal nucleic acid amplification protocols that require low power but high accuracy temperature control in a single well-defined temperature range. We propose temperature control solutions based on commercially available heating elements capable of meeting these challenges, as well as demonstrate the process by which such elements can be fitted to a NINAAT system. Self-regulated and thermostat-controlled resistive heating elements were evaluated through experimental characterization as well as thermal analysis using the finite element method (FEM. We demonstrate that the proposed solutions can support various NAAT protocols, as well as demonstrate an optimal solution for the loop-mediated isothermal amplification (LAMP protocol. Furthermore, we present an Arduino-compatible open-source thermostat developed for NINAAT applications.

  6. Low-Temperature Solution-Processed Gate Dielectrics for High-Performance Organic Thin Film Transistors

    Directory of Open Access Journals (Sweden)

    Jaekyun Kim

    2015-10-01

    Full Text Available A low-temperature solution-processed high-k gate dielectric layer for use in a high-performance solution-processed semiconducting polymer organic thin-film transistor (OTFT was demonstrated. Photochemical activation of sol-gel-derived AlOx films under 150 °C permitted the formation of a dense film with low leakage and relatively high dielectric-permittivity characteristics, which are almost comparable to the results yielded by the conventionally used vacuum deposition and high temperature annealing method. Octadecylphosphonic acid (ODPA self-assembled monolayer (SAM treatment of the AlOx was employed in order to realize high-performance (>0.4 cm2/Vs saturation mobility and low-operation-voltage (<5 V diketopyrrolopyrrole (DPP-based OTFTs on an ultra-thin polyimide film (3-μm thick. Thus, low-temperature photochemically-annealed solution-processed AlOx film with SAM layer is an attractive candidate as a dielectric-layer for use in high-performance organic TFTs operated at low voltages.

  7. Chemistry in high temperature aqueous solutions application to the power industry

    International Nuclear Information System (INIS)

    Cohen, P.

    1990-01-01

    The power industry utilizes water (aqueous solutions) for two main functions: as a medium for heat transfer and transport and as a thermodynamic working fluid. These functions are performed in systems fabricated from a wide variety of materials, over a wide range of thermal and hydraulic conditions, and at medium temperatures and densities which determine the significant chemical properties. The major chemical interest is in the concentrated solutions derived from the dilute working fluid at selected sites defined by the physical arrangement and temperature and in their consequential effects on heat transfer and corrosion. Examples of these sites for typical fossil fired and nuclear steam generating equipment are described, as well as the extent and limit of the concentration process. The history of steam power plant water chemistry is discussed from the point of view of the chemical processes involved. The period covered is from the 1920s to the present state of the art, which is a major application of the subject of this symposium--chemistry in high temperature aqueous solution

  8. Can slow-diffusing solute atoms reduce vacancy diffusion in advanced high-temperature alloys?

    International Nuclear Information System (INIS)

    Goswami, Kamal Nayan; Mottura, Alessandro

    2014-01-01

    The high-temperature mechanical properties of precipitate-strengthened advanced alloys can be heavily influenced by adjusting chemical composition. The widely-accepted argument within the community is that, under certain temperature and loading conditions, plasticity occurs only in the matrix, and dislocations have to rely on thermally-activated climb mechanisms to overcome the barriers to glide posed by the hard precipitates. This is the case for γ′-strengthened Ni-based superalloys. The presence of dilute amounts of slow-diffusing solute atoms, such as Re and W, in the softer matrix phase is thought to reduce plasticity by retarding the climb of dislocations at the interface with the hard precipitate phase. One hypothesis is that the presence of these solutes must hinder the flow of vacancies, which are essential to the climb process. In this work, density functional theory calculations are used to inform two analytical models to describe the effect of solute atoms on the diffusion of vacancies. Results suggest that slow-diffusing solute atoms are not effective at reducing the diffusion of vacancies in these systems

  9. Temperature dependent absorption spectra of Br(-), Br2(•-), and Br3(-) in aqueous solutions.

    Science.gov (United States)

    Lin, Mingzhang; Archirel, Pierre; Van-Oanh, Nguyen Thi; Muroya, Yusa; Fu, Haiying; Yan, Yu; Nagaishi, Ryuji; Kumagai, Yuta; Katsumura, Yosuke; Mostafavi, Mehran

    2011-05-05

    The absorption spectra of Br(2)(•-) and Br(3)(-) in aqueous solutions are investigated by pulse radiolysis techniques from room temperature to 380 and 350 °C, respectively. Br(2)(•-) can be observed even in supercritical conditions, showing that this species could be used as a probe in pulse radiolysis at high temperature and even under supercritical conditions. The weak temperature effect on the absorption spectra of Br(2)(•-) and Br(3)(-) is because, in these two systems, the transition occurs between two valence states; for example, for Br(2)(-) we have (2)Σ(u) → (2)Σ(g) transition. These valence transitions involve no diffuse final state. However, the absorption band of Br(-) undergoes an important red shift to longer wavelengths. We performed classical dynamics of hydrated Br(-) system at 20 and 300 °C under pressure of 25 MPa. The radial distribution functions (rdf's) show that the strong temperature increase (from 20 to 300 °C) does not change the radius of the solvent first shell. On the other hand, it shifts dramatically (by 1 Å) the second maximum of the Br-O rdf and introduces much disorder. This shows that the first water shell is strongly bound to the anion whatever the temperature. The first two water shells form a cavity of a roughly spherical shape around the anion. By TDDFT method, we calculated the absorption spectra of hydrated Br(-) at two temperatures and we compared the results with the experimental data.

  10. The influence of precipitation temperature on the properties of ceria–zirconia solid solution composites

    International Nuclear Information System (INIS)

    Cui, Yajuan; Fang, Ruimei; Shang, Hongyan; Shi, Zhonghua; Gong, Maochu; Chen, Yaoqiang

    2015-01-01

    Highlights: • The crystallite size of precipitate increases as the precipitation temperature rises. • The stack of large crystallite can form nanoparticles with big pore size. • Big pore sizes are advantageous to improve the thermal stability. • Phase segregation is restricted in CZ solid solution precipitated at 70 °C. • The reducibility and OSC of the solid solution precipitated at 70 °C are improved. - Abstract: The ceria–zirconia composites (CZ) with a Ce/Zr mass ratio of 1/1 were synthesized by a back-titration method, in which the influence of precipitation temperature on the properties of ceria–zirconia precipitates was investigated. The resulting precipitation and mixed oxides at different precipitation temperatures were then characterized by a range of techniques, including textural properties, X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), H 2 -temperature programmed reduction (H 2 -TPR) as well as oxygen storage capacity (OSC) measurement. The results revealed that ceria–zirconia composites were formed as solid solution and such structure is favored of thermostability and texture properties. In particular, the composite CZ-70 synthesized at 70 °C exhibited prominent thermostability with a surface area of 32 m 2 /g as well as a pore volume of 0.15 cc/g after aging treatment at 1000 °C for 5 h. And this was found to be associated with the wider pore size distribution which maybe owed to the formation of large crystal at the primary stage of precipitation. Additionally, the composite CZ-70 showed excellent reduction property and OSC benefiting from stable texture and structure

  11. Temperature and pH driven association in uranyl aqueous solutions

    Directory of Open Access Journals (Sweden)

    M. Druchok

    2012-12-01

    Full Text Available An association behavior of uranyl ions in aqueous solutions is explored. For this purpose a set of all-atom molecular dynamics simulations is performed. During the simulation, the fractions of uranyl ions involved in dimer and trimer formations were monitored. To accompany the fraction statistics one also collected distributions characterizing average times of the dimer and trimer associates. Two factors effecting the uranyl association were considered: temperature and pH. As one can expect, an increase of the temperature decreases an uranyl capability of forming the associates, thus lowering bound fractions/times and vice versa. The effect of pH was modeled by adding H+ or OH- ions to a "neutral" solution. The addition of hydroxide ions OH- favors the formation of the associates, thus increasing bound times and fractions. The extra H+ ions in a solution produce an opposite effect, thus lowering the uranyl association capability. We also made a structural analysis for all the observed associates to reveal the mutual orientation of the uranyl ions.

  12. Straining electrode behavior and corrosion resistance of nickel base alloys in high temperature acidic solution

    International Nuclear Information System (INIS)

    Yamanaka, Kazuo

    1992-01-01

    Repassivation behavior and IGA resistance of nickel base alloys containing 0∼30 wt% chromium was investigated in high temperature acid sulfate solution. (1) The repassivation rate was increased with increasing chromium content. And so the amounts of charge caused by the metal dissolution were decreased with increasing chromium content. (2) Mill-annealed Alloy 600 suffered IGA at low pH environment below about 3.5 at the fixed potentials above the corrosion potential in 10%Na 2 SO 4 +H 2 SO 4 solution at 598K. On the other hand, thermally-treated Alloy 690 was hard to occur IGA at low pH environments which mill-annealed Alloy 600 occurred IGA. (3) It was considered that the reason, why nickel base alloys containing high chromium content such as Alloy 690 (60%Ni-30%Cr-10%Fe) had high IGA/SCC resistance in high temperature acidic solution containing sulfate ion, is due to both the promotion of the repassivation and the suppression of the film dissolution by the formation of the dense chromium oxide film

  13. Evolution of microstructures in nickel solid solution fatigued at high temperature: occurence of an intragranular cavitation

    International Nuclear Information System (INIS)

    Arnaud, B.

    1986-06-01

    We studied by T.E.M. the microstructures appearing in Nickel solid solution fatigued in push-pull between 0.4 Tm and 0.6 Tm (Tm=melting temperature), the maximum amplitude of stress was imposed: +- 100 MPa, three frequencies were used: 1.25 Hz, 2.5 Hz and 10 Hz. In Ni 6% at Ge the structure of dislocations evolves continuously with the number of cycles: homogeneous distribution of dislocations, cell structure, then development of sub-grains 5 times as big as the cell; these sub-grains are not stable, they break up into cells. This succession of structures suggests a cyclic evolution. The cavities appear for number of cycles greater than a threshold number depending on the temperature and the frequency. The cavities are not distributed uniformly, they are located in zone. According to the conditions of sollicitation, the shape (equiaxe of small stick) and the distribution (uniform, in band, in crown) of the cavities fluctuate. This cavitation exists equally in other materials (Ni 4% at Si, Ni). This intra-granular cavitation has been observed in the same domain of temperatures as the domain of swelling in the same material under bombardment with ions Ni + . Due to this similitude we searched for a segregation of solute (like the induced precipitation by irradiation) but this phenomenon did not occur with our experimental conditions [fr

  14. Asymptotic solutions of glass temperature profiles during steady optical fibre drawing

    KAUST Repository

    Taroni, M.

    2013-03-12

    In this paper we derive realistic simplified models for the high-speed drawing of glass optical fibres via the downdraw method that capture the fluid dynamics and heat transport in the fibre via conduction, convection and radiative heating. We exploit the small aspect ratio of the fibre and the relative orders of magnitude of the dimensionless parameters that characterize the heat transfer to reduce the problem to one- or two-dimensional systems via asymptotic analysis. The resulting equations may be readily solved numerically and in many cases admit exact analytic solutions. The systematic asymptotic breakdown presented is used to elucidate the relative importance of furnace temperature profile, convection, surface radiation and conduction in each portion of the furnace and the role of each in controlling the glass temperature. The models derived predict many of the qualitative features observed in real industrial processes, such as the glass temperature profile within the furnace and the sharp transition in fibre thickness. The models thus offer a desirable route to quick scenario testing, providing valuable practical information about the dependencies of the solution on the parameters and the dominant heat-transport mechanism. © 2013 Springer Science+Business Media Dordrecht.

  15. Practical Considerations for Determination of Glass Transition Temperature of a Maximally Freeze Concentrated Solution.

    Science.gov (United States)

    Pansare, Swapnil K; Patel, Sajal Manubhai

    2016-08-01

    Glass transition temperature is a unique thermal characteristic of amorphous systems and is associated with changes in physical properties such as heat capacity, viscosity, electrical resistance, and molecular mobility. Glass transition temperature for amorphous solids is referred as (T g), whereas for maximally freeze concentrated solution, the notation is (T g'). This article is focused on the factors affecting determination of T g' for application to lyophilization process design and frozen storage stability. Also, this review provides a perspective on use of various types of solutes in protein formulation and their effect on T g'. Although various analytical techniques are used for determination of T g' based on the changes in physical properties associated with glass transition, the differential scanning calorimetry (DSC) is the most commonly used technique. In this article, an overview of DSC technique is provided along with brief discussion on the alternate analytical techniques for T g' determination. Additionally, challenges associated with T g' determination, using DSC for protein formulations, are discussed. The purpose of this review is to provide a practical industry perspective on determination of T g' for protein formulations as it relates to design and development of lyophilization process and/or for frozen storage; however, a comprehensive review of glass transition temperature (T g, T g'), in general, is outside the scope of this work.

  16. Room temperature synthesis of 2D CuO nanoleaves in aqueous solution

    International Nuclear Information System (INIS)

    Zhao Yan; Li Yunling; Wang Zichen; Zhao Jingzhe; Ma Dechong; Hou Shengnan; Li Linzhi; Hao Xinli

    2011-01-01

    A simple room temperature method was reported for the synthesis of CuO nanocrystals in aqueous solution through the sequence of Cu 2+ → Cu(OA) 2 → Cu(OH) 2 → Cu(OH) 4 2- → CuO. Sodium oleate (SOA) was used as the surfactant and shape controller. The as-prepared samples were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible absorption spectroscopy (UV-vis) and differential thermal analysis (DTA). It can be seen that 1D Cu(OH) 2 nanowires were first obtained from Cu(OA) 2 and, at room temperature, converted into 2D CuO nanoleaves (CuO NLs) in a short time under a weakly basic environment. On prolonging the reaction time, the top part of these 2D nanoleaves branched and separated along the long axis to form 1D rod-like nano-CuO because of the assistance of SOA. A possible transformation mechanism of Cu(OH) 2 to CuO nanostructures at room temperature in aqueous solution is discussed. The transformation velocity can be controlled by changing the pH value of the system. The prepared CuO NLs were used to construct an enzyme-free glucose sensor. The detecting results showed that the designed sensor exhibited good amperometric responses towards glucose with good anti-interferent ability.

  17. Extremophiles in Mineral Sulphide Heaps: Some Bacterial Responses to Variable Temperature, Acidity and Solution Composition

    Directory of Open Access Journals (Sweden)

    Helen R. Watling

    2015-07-01

    Full Text Available In heap bioleaching, acidophilic extremophiles contribute to enhanced metal extraction from mineral sulphides through the oxidation of Fe(II and/or reduced inorganic sulphur compounds (RISC, such as elemental sulphur or mineral sulphides, or the degradation of organic compounds derived from the ore, biota or reagents used during mineral processing. The impacts of variable solution acidity and composition, as well as temperature on the three microbiological functions have been examined for up to four bacterial species found in mineral sulphide heaps. The results indicate that bacteria adapt to sufficiently high metal concentrations (Cu, Ni, Co, Zn, As to allow them to function in mineral sulphide heaps and, by engaging alternative metabolic pathways, to extend the solution pH range over which growth is sustained. Fluctuating temperatures during start up in sulphide heaps pose the greatest threat to efficient bacterial colonisation. The large masses of ores in bioleaching heaps mean that high temperatures arising from sulphide oxidation are hard to control initially, when the sulphide content of the ore is greatest. During that period, mesophilic and moderately thermophilic bacteria are markedly reduced in both numbers and activity.

  18. Effect of solution annealing temperature on precipitation in 2205 duplex stainless steel

    International Nuclear Information System (INIS)

    Kashiwar, A.; Vennela, N. Phani; Kamath, S.L.; Khatirkar, R.K.

    2012-01-01

    In the present study, effect of solution annealing temperature (1050 °C and 1100 °C) and isothermal ageing (700 °C: 15 min to 6 h) on the microstructural changes in 2205 duplex stainless steel has been investigated systematically. Scanning electron microscopy and X-ray diffraction were adopted to follow the microstructural evolution, while an energy dispersive spectrometer attached to scanning electron microscope was used to obtain localised chemical information of various phases. The ferritic matrix of the two phase 2205 duplex stainless steel (∼ 45% ferrite and ∼ 55% austenite) undergoes a series of metallurgical transformations during ageing—formation of secondary austenite (γ 2 ) and precipitation of Cr and Mo rich intermetallic (chi-χ and sigma-σ) phases. For solution annealing at 1050 °C, significant amount of carbides were observed in the ferrite grains after 1 h of ageing at 700 °C. χ Phase precipitated after the precipitation of carbides—preferentially at the ferrite–ferrite and also at the ferrite–austenite boundaries. σ Phase was not observed in significant quantity even after 6 h of ageing. The sequence of precipitation in samples solution annealed at 1050 °C was found to be carbides → χ → σ. On the contrary, for samples solution annealed at 1100 °C, the precipitation of χ phase was negligible. χ Phase precipitated before σ phase, preferentially along the ferrite–ferrite grain boundaries and was later consumed in the σ phase precipitation. The σ phase precipitated via the eutectoid transformation of ferrite to yield secondary austenite γ 2 and σ phase in the ferrite and along the ferrite–austenite grain boundaries. An increase in the volume fraction of γ 2 and σ phase with simultaneous decrease in the ferrite was evidenced with ageing. - Highlights: ► Effect of solution annealing temperature on microstructural evolution is studied. ► χ Phase precipitated preferentially in the samples solution annealed at

  19. Effect of solution annealing temperature on precipitation in 2205 duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Kashiwar, A., E-mail: akashiwar@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur-440010, Maharashtra (India); Vennela, N. Phani, E-mail: phanivennela@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur-440010, Maharashtra (India); Kamath, S.L., E-mail: kamath@iitb.ac.in [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay (IITB), Powai, Mumbai-400076, Maharashtra (India); Khatirkar, R.K., E-mail: rajesh.khatirkar@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur-440010, Maharashtra (India)

    2012-12-15

    In the present study, effect of solution annealing temperature (1050 Degree-Sign C and 1100 Degree-Sign C) and isothermal ageing (700 Degree-Sign C: 15 min to 6 h) on the microstructural changes in 2205 duplex stainless steel has been investigated systematically. Scanning electron microscopy and X-ray diffraction were adopted to follow the microstructural evolution, while an energy dispersive spectrometer attached to scanning electron microscope was used to obtain localised chemical information of various phases. The ferritic matrix of the two phase 2205 duplex stainless steel ({approx} 45% ferrite and {approx} 55% austenite) undergoes a series of metallurgical transformations during ageing-formation of secondary austenite ({gamma}{sub 2}) and precipitation of Cr and Mo rich intermetallic (chi-{chi} and sigma-{sigma}) phases. For solution annealing at 1050 Degree-Sign C, significant amount of carbides were observed in the ferrite grains after 1 h of ageing at 700 Degree-Sign C. {chi} Phase precipitated after the precipitation of carbides-preferentially at the ferrite-ferrite and also at the ferrite-austenite boundaries. {sigma} Phase was not observed in significant quantity even after 6 h of ageing. The sequence of precipitation in samples solution annealed at 1050 Degree-Sign C was found to be carbides {yields} {chi} {yields} {sigma}. On the contrary, for samples solution annealed at 1100 Degree-Sign C, the precipitation of {chi} phase was negligible. {chi} Phase precipitated before {sigma} phase, preferentially along the ferrite-ferrite grain boundaries and was later consumed in the {sigma} phase precipitation. The {sigma} phase precipitated via the eutectoid transformation of ferrite to yield secondary austenite {gamma}{sub 2} and {sigma} phase in the ferrite and along the ferrite-austenite grain boundaries. An increase in the volume fraction of {gamma}{sub 2} and {sigma} phase with simultaneous decrease in the ferrite was evidenced with ageing. - Highlights

  20. Synthesis of Novel Temperature- and pH-Sensitive ABA Triblock Copolymers P(DEAEMA-co-MEO2MA-co-OEGMA-b-PEG-b-P(DEAEMA-co-MEO2MA-co-OEGMA: Micellization, Sol–Gel Transitions, and Sustained BSA Release

    Directory of Open Access Journals (Sweden)

    Yanan Han

    2016-11-01

    Full Text Available Novel temperature- and pH-responsive ABA-type triblock copolymers, P(DEAEMA-co-MEO2MA-co-OEGMA-b-PEG-b-P(DEAEMA-co-MEO2MA-co-OEGMA, composed of a poly(ethylene glycol (PEG middle block and temperature- and pH-sensitive outer blocks, were synthesized by atom transfer radical polymerization (ATRP. The composition and structure of the copolymer were characterized by 1H NMR and gel permeation chromatography (GPC. The temperature- and pH-sensitivity, micellization, and the sol–gel transitions of the triblock copolymers in aqueous solutions were studied using transmittance measurements, surface tension, viscosity, fluorescence probe technique, dynamic light scattering (DLS, zeta-potential measurements, and transmission electron microscopy (TEM. The lower critical solution temperature (LCST of the triblock copolymer, which contains a small amount of a weak base group, (N,N-diethylamino ethyl methacrylate (DEAEMA, can be tuned precisely and reversibly by changing the solution pH. When the copolymer concentration was sufficiently high, increasing temperature resulted in the free-flowing solution transformation into a micellar gel. The sol-to-gel transition temperature (Tsol–gel in aqueous solution will continue to decrease as solution concentration increases.

  1. Solution Properties of Water-Soluble “Smart” Poly(N-acryloyl-N′-ethyl piperazine-co-methyl methacrylate

    Directory of Open Access Journals (Sweden)

    G. Roshan Deen

    2012-01-01

    Full Text Available Water-soluble copolymers of N-acryloyl-N′-ethylpiperazine (AcrNEP with methyl methacrylate (MMA were synthesized to high conversion by free-radical solution polymerization. The composition of the copolymers was determined using Fourier Transform Infra-red Spectroscopy (FTIR. Copolymers containing AcrNEP content above 44 mol% were readily soluble in water and exhibited the critical solution temperature behavior. The copolymers were strongly responsive to changes in pH of the external medium due to the presence of tertiary amine functions that could be protonated at low pH. The influence of various factors such as copolymer composition, pH, temperature, salt and surfactant concentration on the LCST of the copolymers were systematically studied. The intrinsic viscosity of the copolymers in dimethyl formamide decreased with increase in temperature due to a decrease in thermodynamic affinity between polymer chains and solvent molecules. The viscosity behavior of the copolymers in sodium chloride solution was similar to that of classical polyelectrolytes and hydrophobically modified polyacrylate systems.

  2. Temperature and pH Responsive Microfibers for Controllable and Variable Ibuprofen Delivery

    Directory of Open Access Journals (Sweden)

    Toan Tran

    2015-01-01

    Full Text Available Electrospun microfibers (MFs composed of pH and temperature responsive polymers can be used for controllable and variable delivery of ibuprofen. First, electrospinning technique was employed to prepare poly(ε-caprolactone (PCL and poly(N-isopropylacrylamide-co-methacrylic acid (pNIPAM-co-MAA MFs containing ibuprofen. It was found that drug release rates from PCL MFs cannot be significantly varied by either temperature (22–40°C or pH values (1.7–7.4. In contrast, the ibuprofen (IP diffusion rates from pNIPAM-co-MAA MFs were very sensitive to changes in both temperature and pH. The IP release from pNIPAM-co-MAA MFs was highly linear and controllable when the temperature was above the lower critical solution temperature (LCST of pNIPAM-co-MAA (33°C and the pH was lower than the pKa of carboxylic acids (pH 2. At room temperature, however, the release rate was dramatically increased by nearly ten times compared to that at higher temperature and lower pH. Such a unique and controllable drug delivery system could be naturally envisioned to find many practical applications in biomedical and pharmaceutical sciences such as programmable transdermal drug delivery.

  3. Solvation behaviour of biologically active compounds in aqueous solutions of antibacterial drug amoxicillin at different temperatures

    International Nuclear Information System (INIS)

    Singla, Meenu; Kumar, Harsh; Jindal, Rajeev

    2014-01-01

    Highlights: • Densities and speeds of sound of amino acids in aqueous amoxicillin solutions. • Partial molar volumes and compressibility of transfer. • Group contribution have been calculated. • (Ion + hydrophilic) and (hydrophilic + hydrophilic) interactions are present. • Pair-wise interactions are dominant in the mixtures. - Abstract: The interactions of glycine (Gly), L-alanine (Ala), L-valine (Val) and L-Leucine (Leu) with drug amoxicillin (AMX) as a function of temperature have been investigated by combination of volumetric and acoustic measurements. Densities and speeds of sound of amino acids in aqueous solutions of amoxicillin have been measured at T = (305.15, 310.15 and 315.15) K and atmospheric pressure. The apparent molar volume (V ϕ ), the partial molar volume (V ϕ 0 ) and standard partial molar volumes of transfer (ΔV ϕ 0 ) for amino acids from water to aqueous amoxicillin solutions have been calculated from density data. Group contributions of amino acids to partial molar volume were determined. Partial molar isentropic compression (κ ϕ,s ) and partial molar isentropic compression of transfer (Δκ ϕ,S 0 ) have been calculated from speed of sound data. The pair and triplet interaction coefficient have been calculated from both the properties. The results have been explained based on competing patterns of interactions of co-solvents and the solute

  4. Fracture analysis of a transversely isotropic high temperature superconductor strip based on real fundamental solutions

    International Nuclear Information System (INIS)

    Gao, Zhiwen; Zhou, Youhe

    2015-01-01

    Highlights: • We studied fracture problem in HTS based on real fundamental solutions. • When the thickness of HTS strip increases the SIF decrease. • A higher applied field leads to a larger stress intensity factor. • The greater the critical current density is, the smaller values of the SIF is. - Abstract: Real fundamental solution for fracture problem of transversely isotropic high temperature superconductor (HTS) strip is obtained. The superconductor E–J constitutive law is characterized by the Bean model where the critical current density is independent of the flux density. Fracture analysis is performed by the methods of singular integral equations which are solved numerically by Gauss–Lobatto–Chybeshev (GSL) collocation method. To guarantee a satisfactory accuracy, the convergence behavior of the kernel function is investigated. Numerical results of fracture parameters are obtained and the effects of the geometric characteristics, applied magnetic field and critical current density on the stress intensity factors (SIF) are discussed

  5. The influence of temperature on the decomposition kinetics of peracetic acid in solutions

    Directory of Open Access Journals (Sweden)

    Kunigk L.

    2001-01-01

    Full Text Available Peracetic acid is a powerful sanitizer that has only recently been introduced in the Brazilian food industry. The main disadvantage of this sanitizer is its decomposition rate. The main purpose of this paper is to present results obtained in experiments carried out to study the decomposition kinetics of peracetic acid in aqueous solutions at 25, 35, 40 and 45 °C. The decompositon of peracetic acid is a first-order reaction. The decomposition rate constants are between 1.71x10-3 h -1 for 25 °C and 9.64x10-3 h-1 for 45 °C. The decomposition rate constant is affected by temperature according to the Arrhenius equation, and the activation energy for the decomposition of peracetic acid in aqueous solutions prepared from the commercial formulation used in this work is 66.20 kJ/mol.

  6. Simultaneous determination of nitric acid and uranium concentrations in aqueous solution from measurements of electrical conductivity, density, and temperature

    International Nuclear Information System (INIS)

    Spencer, B.B.

    1991-01-01

    Nuclear fuel reprocessing plants handle aqueous solutions of nitric acid and uranium in large quantities. Automatic control of process operations requires reliable measurements of these solutes concentration, but this is difficult to directly measure. Physical properties such as solution density and electrical conductivity vary with solute concentration and temperature. Conductivity, density and temperature can be measured accurately with relatively simple and inexpensive devices. These properties can be used to determine solute concentrations will good correlations. This paper provides the appropriate correlations for solutions containing 2 to 6 Molar (M) nitric acid and 0 to 300 g/L uranium metal at temperatures from 25--90 degrees C. The equations are most accurate below 5 M nitric acid, due to a broad maximum in the conductivity curve at 6 M. 12 refs., 9 figs., 6 tabs

  7. Fracture analysis of a transversely isotropic high temperature superconductor strip based on real fundamental solutions

    Science.gov (United States)

    Gao, Zhiwen; Zhou, Youhe

    2015-04-01

    Real fundamental solution for fracture problem of transversely isotropic high temperature superconductor (HTS) strip is obtained. The superconductor E-J constitutive law is characterized by the Bean model where the critical current density is independent of the flux density. Fracture analysis is performed by the methods of singular integral equations which are solved numerically by Gauss-Lobatto-Chybeshev (GSL) collocation method. To guarantee a satisfactory accuracy, the convergence behavior of the kernel function is investigated. Numerical results of fracture parameters are obtained and the effects of the geometric characteristics, applied magnetic field and critical current density on the stress intensity factors (SIF) are discussed.

  8. A new cell for temperature-dependent X-ray absorption spectroscopy of liquid solutions: application to PbBr2 solutions in diethylene glycol.

    Science.gov (United States)

    Lützenkirchen-Hecht, D; Oldag, T; Keil, P; Keller, H L; Frahm, R

    2005-03-01

    An in situ cell has been constructed for temperature-dependent X-ray absorption experiments (EXAFS and XANES) of lead bromine (PbBr2) solutions in diethylene glycol in the temperature range from room temperature up to about 433 K. The solution is kept in a thermostated container made of carbon-reinforced teflon between two thin chemically inert quartz glass windows with a high transmission for hard X-rays. The construction of the cell ensures that these X-ray windows are thermalized so that any possible precipitation of solid products from the solution is inhibited. The cell consists mainly of two hermetically sealed teflon containers for the thermostating fluid (silicon oil) that were fitted together in such a way that a small and variable volume (approximately 2-4 cm3) for the liquid under investigation was achieved. A small thermocouple in a glass enclosure was placed in the solution to maintain temperature control and feedback to the thermostat. The cell design and its performance for temperature-dependent in situ investigations with X-rays are reported. Some preliminary results obtained for PbBr2 solutions in diethylene glycol are given.

  9. Highly conductive p-type amorphous oxides from low-temperature solution processing

    International Nuclear Information System (INIS)

    Li Jinwang; Tokumitsu, Eisuke; Koyano, Mikio; Mitani, Tadaoki; Shimoda, Tatsuya

    2012-01-01

    We report solution-processed, highly conductive (resistivity 1.3-3.8 mΩ cm), p-type amorphous A-B-O (A = Bi, Pb; B = Ru, Ir), processable at temperatures (down to 240 °C) that are compatible with plastic substrates. The film surfaces are smooth on the atomic scale. Bi-Ru-O was analyzed in detail. A small optical bandgap (0.2 eV) with a valence band maximum (VBM) below but very close to the Fermi level (binding energy E VBM = 0.04 eV) explains the high conductivity and suggests that they are degenerated semiconductors. The conductivity changes from three-dimensional to two-dimensional with decreasing temperature across 25 K.

  10. Solution for laminar natural convection flows in a square cavity with temperature dependent viscosity

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, J.G. [Parsons Brinckerhoff, New York, NY (United States)

    1995-12-31

    This paper presents an examination of numerical results for the buoyancy-driven convection heat transfer problem, in a two-dimensional enclosure under steady-state, laminar, incompressible, and temperature dependent viscosity fluid flow conditions. The vertical walls are exposed to different temperatures and the top and bottom are insulated. Rayleigh numbers of 10{sup 4}, 10{sup 5}, and 10{sup 6} are considered. Specific heat, thermal conductivity, and the thermal expansion coefficient are assumed constant. Density variation is included using the Oberbeck-Boussinesq approximation. The results are obtained using the SIMPLEC solution technique based on a power-law, finite-volume discretization scheme. The hydrodynamic and thermal fields are presented at various locations in the enclosures.

  11. On a closed form solution of the point kinetics equations with reactivity feedback of temperature

    International Nuclear Information System (INIS)

    Silva, Jeronimo J.A.; Vilhena, Marco T.M.B.; Petersen, Claudio Z.; Bodmann, Bardo E.J.; Alvim, Antonio C.M.

    2011-01-01

    An analytical solution of the point kinetics equations to calculate reactivity as a function of time by the Decomposition method has recently appeared in the literature. In this paper, we go one step forward, by considering the neutron point kinetics equations together with temperature feedback effects. To accomplish that, we extended the point kinetics by a temperature perturbation, obtaining a second order nonlinear ordinary differential equation. This equation is then solved by the Decomposition Method, that is, by expanding the neutron density in a series and the nonlinear terms into Adomian Polynomials. Substituting these expansions into the nonlinear ordinary equation, we construct a recursive set of linear problems that can be solved by the methodology previously mentioned for the point kinetics equation. We also report on numerical simulations and comparisons against literature results. (author)

  12. Simple and accurate solution for convective-radiative fin with temperature dependent thermal conductivity using double optimal linearization

    International Nuclear Information System (INIS)

    Bouaziz, M.N.; Aziz, Abdul

    2010-01-01

    A novel concept of double optimal linearization is introduced and used to obtain a simple and accurate solution for the temperature distribution in a straight rectangular convective-radiative fin with temperature dependent thermal conductivity. The solution is built from the classical solution for a pure convection fin of constant thermal conductivity which appears in terms of hyperbolic functions. When compared with the direct numerical solution, the double optimally linearized solution is found to be accurate within 4% for a range of radiation-conduction and thermal conductivity parameters that are likely to be encountered in practice. The present solution is simple and offers superior accuracy compared with the fairly complex approximate solutions based on the homotopy perturbation method, variational iteration method, and the double series regular perturbation method. The fin efficiency expression resembles the classical result for the constant thermal conductivity convecting fin. The present results are easily usable by the practicing engineers in their thermal design and analysis work involving fins.

  13. Thermodynamics of protonation of amines in aqueous solutions at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Inna, E-mail: inna.kim@sintef.no [SINTEF Materials and Chemistry, N-7465 Trondheim (Norway); Jens, Christian M., E-mail: chrijens@stud.ntnu.no [Norwegian University of Science and Technology (NTNU), N-7491 Trondheim (Norway); Grimstvedt, Andreas, E-mail: andreas.grimstvedt@sintef.no [SINTEF Materials and Chemistry, N-7465 Trondheim (Norway); Svendsen, Hallvard F., E-mail: hallvard.svendsen@chemeng.ntnu.no [Norwegian University of Science and Technology (NTNU), N-7491 Trondheim (Norway)

    2011-11-15

    Highlights: > Effect of ionic strength and temperature on dissociation constants of amines. > Effect of ionic strength of temperature on enthalpies of protonation of amines. > Measured dissociation constants and enthalpies of protonation used for fitting. > Coefficients for thermodynamically consistent correlations given for 5 amines. - Abstract: The dissociation constants, pK{sub a}, of monoethanolamine (MEA), N-methyldiethanolamine (MDEA), 2-amino-2-methyl-1-propanol (AMP), 2(2-aminoethyl)etanolamine (AEEA), and piperazine (Pz) were measured by potentiometric titration over the temperature range (298.15 to 363.15) K. Enthalpies of protonation, {Delta}H{sub p}, were measured calorimetrically at temperatures from (298.15 to 393.15) K for MEA, MDEA, and AMP, and from (298.15 to 353.15) K for AEEA and Pz. In addition, the effect of the ionic strength of the solutions on the protonation of MDEA was studied using NaCl as background salt {l_brace}(0 to 5.5) mol/kg-H{sub 2}O){r_brace}. Correlations for the reaction equilibrium constants for proton dissociation are proposed for the studied amines based on the experimental data from literature and from this work. Both experimental enthalpy data and dissociation constants were used for fitting. The results from this work may be used for thermodynamic modeling of CO{sub 2} capture processes using amines.

  14. Effect of temperature on the dilution enthalpies of α,ω-amino acids in aqueous solutions

    International Nuclear Information System (INIS)

    Romero, C.M.; Cadena, J.C.; Lamprecht, I.

    2011-01-01

    Highlights: → The dilution of 3-amino propanoic acid, 4-amino butanoic acid, 5-amino pentanoic acid, and 6-amino hexanoic acid in water is an exothermic process at T = (293.15, 298.15, 303.15, and 308.15) K. → The limiting experimental slopes of the enthalpies of dilution with respect to the molality change Δm, are negative suggesting that the solutes interact with water primarily through their alkyl groups. → The value of the pairwise coefficient is positive at the temperatures considered, and the magnitude increases linearly with the number of methylene groups. → The comparison between the pairwise interaction coefficients for α,ω-amino acids and α-amino acids shows that the change in the enthalpic interaction coefficient is related to the relative position of the polar groups. - Abstract: Dilution enthalpies of aqueous solutions of 3-amino propanoic acid, 4-amino butanoic acid, 5-amino pentanoic acid, and 6-amino hexanoic acid were determined at T = (293.15, 298.15, 303.15, and 308.15) K using an LKB flow microcalorimeter. The homotactic interaction coefficients were obtained according to the McMillan-Mayer theory from the experimental data. For all the systems studied, the dilution of α,ω-amino acids in water is an exothermic process; the pair coefficients have positive values which increases with chain length. The obtained values of the interaction coefficients are interpreted in terms of solute-solvent and solute-solute interactions and are used as indicative of hydrophobic behavior of the amino acid studied.

  15. Correlation of high-temperature stability of alpha-chymotrypsin with 'salting-in' properties of solution.

    Science.gov (United States)

    Levitsky VYu; Panova, A A; Mozhaev, V V

    1994-01-15

    A correlation between the stability of alpha-chymotrypsin against irreversible thermal inactivation at high temperatures (long-term stability) and the coefficient of Setchenov equation as a measure of salting-in/out efficiency of solutes in the Hofmeister series has been found. An increase in the concentration of salting-in solutes (KSCN, urea, guanidinium chloride, formamide) leads to a many-fold decrease of the inactivation rate of the enzyme. In contrast, addition of salting-out solutes has a small effect on the long-term stability of alpha-chymotrypsin at high temperatures. The effects of solutes are additive with respect to their salting-in/out capacities; the stabilizing action of the solutes is determined by the calculated Setchenov coefficient of solution. The correlation is explained by a solute-driven shift of the conformational equilibrium between the 'low-temperature' native and the 'high-temperature' denatured forms of the enzyme within the range of the kinetic scheme put forward in the preceding paper in this journal: irreversible inactivation of the high-temperature form proceeds much more slowly compared with the low-temperature form.

  16. Effect of temperature on chlorproguanil and proguanil hydrochloride solutions: a chemical stability study.

    Science.gov (United States)

    Kolawole, J A; Mustapha, A; Abdul-Aguye, I; Ochekpe, N

    1996-04-01

    Chlorproguanil and proguanil hydrochloride solutions in 0.5 M hydrochloric acid, water and 1 M ammonium hydroxide were subjected to different temperatures (22-80 degrees C) for 68 h. The decomposition rate constants for chlorproguanil ranged from 1.60 to 47.6 x 10(3) h-1 in acid, 3.5 to 18 x 10(3) h-1 in water and 3.87 to 32.5 x 10(3) h-1 in base, between 50 degrees C and 80 degrees C. The activation energy Ea was 96.5, 52.12 and 62.1 kJ mol-1 in acid, water and base respectively. The proguanil decomposition rate constant ranged from 1.72 to 18.5 x 10(3) h-1 in acid, 1.58 to 9.67 x 10(3) h-1 in water and 2.34 to 15.77 x 10(3) h-1 in base, between 50 degrees C and 80 degrees C, with Ea values of 54.7, 73.3 and 62.5 kJ mol-1. Three unidentified degradation products were separated in the acid solution for each of the compounds. Chlorproguanil and proguanil are stable (t1/2 values over 30 days and up to 287 days respectively) in acid, water and base at temperatures below 22 degrees C.

  17. Pitting corrosion of Inconel 600 in chloride and sulfate solutions at low temperature

    International Nuclear Information System (INIS)

    Chang Mingyu; Yu Geping

    1993-01-01

    Pitting corrosion of Inconel 600 was examined in chloride and sulfate solutions through usage of potentiodynamic polarization techniques. The effects of chloride and sulfate concentration were investigated in the range of 0.0001 to 0.1 M. Increasing chloride concentrations resulted in active shifts of the pit nucleation potential. Immunity to pitting corrosion was evident at a chloride level below 0.005 M. Increasing sulfate concentrations resulted in improved pitting resistance of Inconel 600 in chloride solutions. Detrimental effects associated with pitting were evident with low-level sulfate being added to dilute chloride media. The density of pits increased with increasing chloride concentrations or temperature between room temperature and 70 C. Systematic trends for the depth of pits were not evident. The observations of pitting corrosion in open immersion were consistent with those in polarization methods. Corrosion products contained in the pits were enriched in nickel, chromium and iron with a small amount of titanium and silicon. The enrichment of chlorine or sulfur was still, however, not found. (orig.)

  18. Single molecule dynamics at a mechanically controllable break junction in solution at room temperature.

    Science.gov (United States)

    Konishi, Tatsuya; Kiguchi, Manabu; Takase, Mai; Nagasawa, Fumika; Nabika, Hideki; Ikeda, Katsuyoshi; Uosaki, Kohei; Ueno, Kosei; Misawa, Hiroaki; Murakoshi, Kei

    2013-01-23

    The in situ observation of geometrical and electronic structural dynamics of a single molecule junction is critically important in order to further progress in molecular electronics. Observations of single molecular junctions are difficult, however, because of sensitivity limits. Here, we report surface-enhanced Raman scattering (SERS) of a single 4,4'-bipyridine molecule under conditions of in situ current flow in a nanogap, by using nano-fabricated, mechanically controllable break junction (MCBJ) electrodes. When adsorbed at room temperature on metal nanoelectrodes in solution to form a single molecule junction, statistical analysis showed that nontotally symmetric b(1) and b(2) modes of 4,4'-bipyridine were strongly enhanced relative to observations of the same modes in solid or aqueous solutions. Significant changes in SERS intensity, energy (wavenumber), and selectivity of Raman vibrational bands that are coincident with current fluctuations provide information on distinct states of electronic and geometrical structure of the single molecule junction, even under large thermal fluctuations occurring at room temperature. We observed the dynamics of 4,4'-bipyridine motion between vertical and tilting configurations in the Au nanogap via b(1) and b(2) mode switching. A slight increase in the tilting angle of the molecule was also observed by noting the increase in the energies of Raman modes and the decrease in conductance of the molecular junction.

  19. Temperature-Responsive Smart Nanocarriers for Delivery Of Therapeutic Agents: Applications and Recent Advances.

    Science.gov (United States)

    Karimi, Mahdi; Sahandi Zangabad, Parham; Ghasemi, Alireza; Amiri, Mohammad; Bahrami, Mohsen; Malekzad, Hedieh; Ghahramanzadeh Asl, Hadi; Mahdieh, Zahra; Bozorgomid, Mahnaz; Ghasemi, Amir; Rahmani Taji Boyuk, Mohammad Reza; Hamblin, Michael R

    2016-08-24

    Smart drug delivery systems (DDSs) have attracted the attention of many scientists, as carriers that can be stimulated by changes in environmental parameters such as temperature, pH, light, electromagnetic fields, mechanical forces, etc. These smart nanocarriers can release their cargo on demand when their target is reached and the stimulus is applied. Using the techniques of nanotechnology, these nanocarriers can be tailored to be target-specific, and exhibit delayed or controlled release of drugs. Temperature-responsive nanocarriers are one of most important groups of smart nanoparticles (NPs) that have been investigated during the past decades. Temperature can either act as an external stimulus when heat is applied from the outside, or can be internal when pathological lesions have a naturally elevated termperature. A low critical solution temperature (LCST) is a special feature of some polymeric materials, and most of the temperature-responsive nanocarriers have been designed based on this feature. In this review, we attempt to summarize recent efforts to prepare innovative temperature-responsive nanocarriers and discuss their novel applications.

  20. Solution equilibrium behind the room-temperature synthesis of nanocrystalline titanium dioxide

    Science.gov (United States)

    Seisenbaeva, Gulaim A.; Daniel, Geoffrey; Nedelec, Jean-Marie; Kessler, Vadim G.

    2013-03-01

    Formation of nanocrystalline and monodisperse TiO2 from a water soluble and stable precursor, ammonium oxo-lactato-titanate, (NH4)8Ti4O4(Lactate)8.4H2O, often referred to as TiBALDH or TALH, is demonstrated to be due to a coordination equilibrium. This compound, individual in the solid state, exists in solution in equilibrium with ammonium tris-lactato-titanate, (NH4)2Ti(Lactate)3 and uniform crystalline TiO2 nanoparticles (anatase) stabilized by surface-capping with lactate ligands. This equilibrium can be shifted towards nano-TiO2via application of a less polar solvent like methanol or ethanol, dilution of the solution, introduction of salts or raising the temperature, and reverted on addition of polar and strongly solvating media such as dimethyl sulfoxide, according to NMR. Aggregation and precipitation of the particles were followed by DLS and could be achieved by a decrease in their surface charge by adsorption of strongly hydrogen-bonding cations, e.g. in solutions of ammonia, ethanolamine or amino acid arginine or by addition of ethanol. The observed equilibrium may be involved in formation of nano-titania on the surface of plant roots exerting chelating organic carboxylate ligands and thus potentially influencing plant interactions.Formation of nanocrystalline and monodisperse TiO2 from a water soluble and stable precursor, ammonium oxo-lactato-titanate, (NH4)8Ti4O4(Lactate)8.4H2O, often referred to as TiBALDH or TALH, is demonstrated to be due to a coordination equilibrium. This compound, individual in the solid state, exists in solution in equilibrium with ammonium tris-lactato-titanate, (NH4)2Ti(Lactate)3 and uniform crystalline TiO2 nanoparticles (anatase) stabilized by surface-capping with lactate ligands. This equilibrium can be shifted towards nano-TiO2via application of a less polar solvent like methanol or ethanol, dilution of the solution, introduction of salts or raising the temperature, and reverted on addition of polar and strongly solvating

  1. Estimation of influence of a solution of a boric acid and temperatures on a isolation material from basalt fibers

    International Nuclear Information System (INIS)

    Pyshnova, V.V.; Skobelkina, T.N.; Yurchenko, V.G.; Knot'ko, A.V.; Putlyaev, V.I.

    2006-01-01

    Paper presents the results of investigation into long-term simultaneous effect of a medium (boric acid solution) and temperature on a thermal-insulating basalt fiber material. The basalt fiber clothes used at the NPP were tested. When evaluating simultaneous effect of boric acid solution and temperature one kept watch on density, compressibility, elasticity and diameter of fiber. According to the results of 30 day tests, the basic technical parameters of the thermal-insulating material have changed insignificantly [ru

  2. Analytical solution and numerical simulation of the liquid nitrogen freezing-temperature field of a single pipe

    Science.gov (United States)

    Cai, Haibing; Xu, Liuxun; Yang, Yugui; Li, Longqi

    2018-05-01

    Artificial liquid nitrogen freezing technology is widely used in urban underground engineering due to its technical advantages, such as simple freezing system, high freezing speed, low freezing temperature, high strength of frozen soil, and absence of pollution. However, technical difficulties such as undefined range of liquid nitrogen freezing and thickness of frozen wall gradually emerge during the application process. Thus, the analytical solution of the freezing-temperature field of a single pipe is established considering the freezing temperature of soil and the constant temperature of freezing pipe wall. This solution is then applied in a liquid nitrogen freezing project. Calculation results show that the radius of freezing front of liquid nitrogen is proportional to the square root of freezing time. The radius of the freezing front also decreases with decreased the freezing temperature, and the temperature gradient of soil decreases with increased distance from the freezing pipe. The radius of cooling zone in the unfrozen area is approximately four times the radius of the freezing front. Meanwhile, the numerical simulation of the liquid nitrogen freezing-temperature field of a single pipe is conducted using the Abaqus finite-element program. Results show that the numerical simulation of soil temperature distribution law well agrees with the analytical solution, further verifies the reliability of the established analytical solution of the liquid nitrogen freezing-temperature field of a single pipe.

  3. Material degradation due to moisture and temperature. Part 1: mathematical model, analysis, and analytical solutions

    Science.gov (United States)

    Xu, C.; Mudunuru, M. K.; Nakshatrala, K. B.

    2016-11-01

    The mechanical response, serviceability, and load-bearing capacity of materials and structural components can be adversely affected due to external stimuli, which include exposure to a corrosive chemical species, high temperatures, temperature fluctuations (i.e., freezing-thawing), cyclic mechanical loading, just to name a few. It is, therefore, of paramount importance in several branches of engineering—ranging from aerospace engineering, civil engineering to biomedical engineering—to have a fundamental understanding of degradation of materials, as the materials in these applications are often subjected to adverse environments. As a result of recent advancements in material science, new materials such as fiber-reinforced polymers and multi-functional materials that exhibit high ductility have been developed and widely used, for example, as infrastructural materials or in medical devices (e.g., stents). The traditional small-strain approaches of modeling these materials will not be adequate. In this paper, we study degradation of materials due to an exposure to chemical species and temperature under large strain and large deformations. In the first part of our research work, we present a consistent mathematical model with firm thermodynamic underpinning. We then obtain semi-analytical solutions of several canonical problems to illustrate the nature of the quasi-static and unsteady behaviors of degrading hyperelastic solids.

  4. Copper(II) oxide solubility behavior in aqueous sodium phosphate solutions at elevated temperatures

    International Nuclear Information System (INIS)

    Ziemniak, S.E.; Jones, M.E.; Combs, K.E.S.

    1990-02-01

    A platinum-lined, flowing autoclave facility is used to investigate the solubility behavior of copper(II) oxide (CuO) in aqueous sodium phosphate solutions at temperatures between 292 and 535 K. Copper solubilities are observed to increase continuously with temperature and phosphate concentration. The measured solubility is examined via a Cu(II) ion hydrolysis/complexing model and thermodynamic functions for the hydrolysis/complexing reactions are obtained from a least- squares analysis of the data. Altogether, thermochemical properties are established for five anionic complexes: Cu(OH) 3 - , Cu(OH) 4 = , Cu(OH) 2 (HPO 4 ) = , Cu(OH) 3 (H 2 PO 4 ) = , and Cu(OH) 2 (PO 4 ) ≡ . Precise thermochemical parameters are also derived for the Cu(OH) + hydroxocomplex based on CuO solubility behavior previously observed in pure water (*) at elevated temperatures. The relative ease of Cu(II) ion hydrolysis is such that Cu(OH) 3 - species become the preferred hydroxocomplex for pH ≥ 9.4. 20 refs., 8 figs., 6 tabs

  5. Room-temperature solution synthesis of Ag nanoparticle functionalized molybdenum oxide nanowires and their catalytic applications

    International Nuclear Information System (INIS)

    Dong Wenjun; Huang Huandi; Zhu Yanjun; Li Xiaoyun; Wang Xuebin; Li Chaorong; Chen Benyong; Wang Ge; Shi Zhan

    2012-01-01

    A simple chemical solution route for the synthesis of large-scale high-quality Ag nanoparticle functionalized molybdenum oxide nanowire at room temperature has been developed. In the synthesis, the protonated amine was intercalated into the molybdenum bronze layers to reduce the electrostatic force of the lamellar structures, and then the Ag nanoparticle functionalized long nanowires could be easily induced by a redox reaction between a molybdenum oxide–amine intermediate and Ag + at room temperature. The intercalation lamellar structures improved the nucleation and growth of the Ag nanoparticles, with the result that uniform Ag nanoparticles occurred on the surface of the MoO 3 nanowire. In this way Ag nanoparticles with average sizes of around 6 nm, and high-purity nanowires with mean diameter of around 50 nm and with typical lengths of several tens to hundreds of micrometers were produced. The heteronanostructured nanowires were intricately and inseparably connected to each other with hydrogen bonds and/or bridge oxygen atoms and packed together, forming a paper-like porous network film. The Ag–MoO 3 nanowire film performs a promoted catalytic property for the epoxidation of cis-cyclooctene, and the heteronanostructured nanowire film sensor shows excellent sensing performance to hydrogen and oxygen at room temperature. (paper)

  6. Cathodic deposition of CdSe films from dimethyl formamide solution at optimized temperature

    Energy Technology Data Exchange (ETDEWEB)

    Datta, J. [Department of Chemistry, Bengal Engineering and Science University, Shibpur, Howrah 711 103, West Bengal (India)]. E-mail: jayati_datta@rediffmail.com; Bhattacharya, C. [Department of Chemistry, Bengal Engineering and Science University, Shibpur, Howrah 711 103, West Bengal (India); Visiting Research Associate, School of Materials Science and Engineering, UNSW (Australia); Bandyopadhyay, S. [School of Materials Science and Engineering, UNSW, Sydney 2052 (Australia)

    2006-12-15

    In the present paper, thin film CdSe compound semiconductors have been electroplated on transparent conducting oxide coated glass substrates from nonaqueous dimethyl formamide bath containing CdCl{sub 2}, KI and Se under controlled temperature ranging from 100 to 140 deg. C. Thickness of the deposited films as obtained through focussed ion beam technique as well as their microstructural and photoelectrochemical properties have been found to depend on temperature. The film growth was therefore optimized at a bath temperature {approx}125 deg. C. The formation of crystallites in the range of 100-150 nm size has been ascertained through atomic force microscopy and scanning electron microscopy. Energy dispersive analysis of X-rays for the as deposited film confirmed the 1:1 composition of CdSe compound in the matrix exhibiting band-gap energy of 1.74 eV. Microstructural properties of the deposited films have been determined through X-ray diffraction studies, high-resolution transmission electron microscopy and electron diffraction pattern analysis. Electrochemical impedance spectroscopy and current-potential measurements have been performed to characterize the electrochemical behavior of the semiconductor-electrolyte interface. The photo-activity of the films have been recorded in polysulphide solution under illumination and solar conversion efficiency {>=}1% was achieved.

  7. Characterization of Modified Tapioca Starch Solutions and Their Sprays for High Temperature Coating Applications

    Science.gov (United States)

    Naz, M. Y.; Sulaiman, S. A.; Ariwahjoedi, B.; Shaari, Ku Zilati Ku

    2014-01-01

    The objective of the research was to understand and improve the unusual physical and atomization properties of the complexes/adhesives derived from the tapioca starch by addition of borate and urea. The characterization of physical properties of the synthesized adhesives was carried out by determining the effect of temperature, shear rate, and mass concentration of thickener/stabilizer on the complex viscosity, density, and surface tension. In later stage, phenomenological analyses of spray jet breakup of heated complexes were performed in still air. Using a high speed digital camera, the jet breakup dynamics were visualized as a function of the system input parameters. The further analysis of the grabbed images confirmed the strong influence of the input processing parameters on full cone spray patternation. It was also predicted that the heated starch adhesive solutions generate a dispersed spray pattern by utilizing the partial evaporation of the spraying medium. Below 40°C of heating temperature, the radial spray cone width and angle did not vary significantly with increasing Reynolds and Weber numbers at early injection phases leading to increased macroscopic spray propagation. The discharge coefficient, mean flow rate, and mean flow velocity were significantly influenced by the load pressure but less affected by the temperature. PMID:24592165

  8. Room-temperature solution synthesis of Ag nanoparticle functionalized molybdenum oxide nanowires and their catalytic applications.

    Science.gov (United States)

    Dong, Wenjun; Huang, Huandi; Zhu, Yanjun; Li, Xiaoyun; Wang, Xuebin; Li, Chaorong; Chen, Benyong; Wang, Ge; Shi, Zhan

    2012-10-26

    A simple chemical solution route for the synthesis of large-scale high-quality Ag nanoparticle functionalized molybdenum oxide nanowire at room temperature has been developed. In the synthesis, the protonated amine was intercalated into the molybdenum bronze layers to reduce the electrostatic force of the lamellar structures, and then the Ag nanoparticle functionalized long nanowires could be easily induced by a redox reaction between a molybdenum oxide-amine intermediate and Ag(+) at room temperature. The intercalation lamellar structures improved the nucleation and growth of the Ag nanoparticles, with the result that uniform Ag nanoparticles occurred on the surface of the MoO(3) nanowire. In this way Ag nanoparticles with average sizes of around 6 nm, and high-purity nanowires with mean diameter of around 50 nm and with typical lengths of several tens to hundreds of micrometers were produced. The heteronanostructured nanowires were intricately and inseparably connected to each other with hydrogen bonds and/or bridge oxygen atoms and packed together, forming a paper-like porous network film. The Ag-MoO(3) nanowire film performs a promoted catalytic property for the epoxidation of cis-cyclooctene, and the heteronanostructured nanowire film sensor shows excellent sensing performance to hydrogen and oxygen at room temperature.

  9. High-Pressure-High-Temperature Processing Reduces Maillard Reaction and Viscosity in Whey Protein-Sugar Solutions

    NARCIS (Netherlands)

    Avila Ruiz, Geraldine; Xi, Bingyan; Minor, Marcel; Sala, Guido; Boekel, van Tiny; Fogliano, Vincenzo; Stieger, Markus

    2016-01-01

    The aim of the study was to determine the influence of pressure in high-pressure-high-temperature (HPHT) processing on Maillard reactions and protein aggregation of whey protein-sugar solutions. Solutions of whey protein isolate containing either glucose or trehalose at pH 6, 7, and 9 were

  10. Structural studies of aqueous solutions at high temperatures. Critical opalescence and hydration

    International Nuclear Information System (INIS)

    Sullivan, D.M.

    2000-09-01

    Neutron scattering techniques were used to study aspects of the static, or equilibrium, structure at microscopic scales in a number of aqueous solutions at non ambient conditions (Temperature, T > 300 K, and pressure, P > 1 bar). Critical opalescence was observed in both pure D 2 O and a NaCI-D 2 O mixture by means of small-angle neutron scattering (SANS), as described in Part I. The dependence of the correlation length, ξ, and the long wavelength limit, S(0), was measured at a number of state points on the critical isochore. The results are interpreted in terms of theories of critical phenomena; in particular the expected power law behaviour of ξ and S(0) with respect to reduced temperature, t, on the critical isochore. In the case of D 2 O, we observe the expected 3d-Ising behaviour with exponents (ν = 0.623 ± 0.030, γ = 1.14 ± 0.05) and amplitudes in agreement with theoretical and semi-empirical predictions. We performed measurements on aqueous sodium chloride, equivalent to those on pure 020, with the intention of classifying the critical behaviour. Although strong power-law divergence of the quantities ξ and S(0) was not observed, we find that the value of S(0) for a given ξ is strongly reduced in the ionic solution with respect to the pure solvent. Such behaviour is inconsistent with a thermodynamic model of aqueous sodium chloride, based on experimental thermodynamic data and the expected asymptotic 3d-Ising behaviour. Short-range structural correlations between solute and solvent atoms in aqueous solutions were studied by the technique of neutron diffraction and isotopic substitution (NDIS), as described in Part II. The anion hydration structure in 1.5 molal aqueous NaCl, was investigated at (T = 580 K, P = 800 bar) and (T = 380 K, P = 200 bar). Isotopic substitution was performed on the chloride ion, enabling the difference between scattering functions to be interpreted in terms of CI-H and CI-O correlation functions. The results show the chloride

  11. Structural studies of aqueous solutions at high temperatures. Critical opalescence and hydration

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, D.M

    2000-09-01

    Neutron scattering techniques were used to study aspects of the static, or equilibrium, structure at microscopic scales in a number of aqueous solutions at non ambient conditions (Temperature, T > 300 K, and pressure, P > 1 bar). Critical opalescence was observed in both pure D{sub 2}O and a NaCI-D{sub 2}O mixture by means of small-angle neutron scattering (SANS), as described in Part I. The dependence of the correlation length, {xi}, and the long wavelength limit, S(0), was measured at a number of state points on the critical isochore. The results are interpreted in terms of theories of critical phenomena; in particular the expected power law behaviour of {xi} and S(0) with respect to reduced temperature, t, on the critical isochore. In the case of D{sub 2}O, we observe the expected 3d-Ising behaviour with exponents ({nu} = 0.623 {+-} 0.030, {gamma} = 1.14 {+-} 0.05) and amplitudes in agreement with theoretical and semi-empirical predictions. We performed measurements on aqueous sodium chloride, equivalent to those on pure 020, with the intention of classifying the critical behaviour. Although strong power-law divergence of the quantities {xi} and S(0) was not observed, we find that the value of S(0) for a given {xi} is strongly reduced in the ionic solution with respect to the pure solvent. Such behaviour is inconsistent with a thermodynamic model of aqueous sodium chloride, based on experimental thermodynamic data and the expected asymptotic 3d-Ising behaviour. Short-range structural correlations between solute and solvent atoms in aqueous solutions were studied by the technique of neutron diffraction and isotopic substitution (NDIS), as described in Part II. The anion hydration structure in 1.5 molal aqueous NaCl, was investigated at (T = 580 K, P = 800 bar) and (T = 380 K, P = 200 bar). Isotopic substitution was performed on the chloride ion, enabling the difference between scattering functions to be interpreted in terms of CI-H and CI-O correlation functions

  12. IPN hydrogels based on PNIPAAm and PVA-Ma networks: characterization through measure of LCST, swelling ratio and mechanical properties - doi: 10.4025/actascitechnol.v34i2.15019

    OpenAIRE

    Wenceslau, Adriana Cristina; Universidade Estadual de Maringá - UEM; Rubira, Adley Forti; Universidade Estadual de Maringá - UEM; Muniz, Edvani Curti; UEM, Maringá, Paraná

    2011-01-01

    IPN hydrogels based on chemically modified poly(vinyl alcohol) (or PVA-Ma), with different degrees of substitution (DS), and poly(N-isopropylacrylamide) (or PNIPAAm) were obtained and characterized through measures of LCST, swelling ratio and mechanical properties. Linear PVA-Ma with several DS were obtained through the chemical reaction of PVA with glycidyl methacrylate (GMA). The DS of various PVA-Ma were determined through 1H NMR spectroscopy. Two steps were used for preparation the PVA-Ma...

  13. Surface properties of magnetite in high temperature aqueous electrolyte solutions: A review.

    Science.gov (United States)

    Vidojkovic, Sonja M; Rakin, Marko P

    2017-07-01

    Deposits and scales formed on heat transfer surfaces in power plant water/steam circuits have a significant negative impact on plant reliability, availability and performance, causing tremendous economic consequences and subsequent increases in electricity cost. Consequently, the improvement of the understanding of deposition mechanisms on power generating surfaces is defined as a high priority in the power industry. The deposits consist principally of iron oxides, which are steel corrosion products and usually present in colloidal form. Magnetite (Fe 3 O 4 ) is the predominant and most abundant compound found in water/steam cycles of all types of power plants. The crucial factor that governs the deposition process and influences the deposition rate of magnetite is the electrostatic interaction between the metal wall surfaces and the suspended colloidal particles. However, there is scarcity of data on magnetite surface properties at elevated temperatures due to difficulties in their experimental measurement. In this paper a generalized overview of existing experimental data on surface characteristics of magnetite at high temperatures is presented with particular emphasis on possible application in the power industry. A thorough analysis of experimental techniques, mathematical models and results has been performed and directions for future investigations have been considered. The state-of-the-art assessment showed that for the characterization of magnetite/aqueous electrolyte solution interface at high temperatures acid-base potentiometric titrations and electrophoresis were the most beneficial and dependable techniques which yielded results up to 290 and 200°C, respectively. Mass titrations provided data on magnetite surface charge up to 320°C, however, this technique is highly sensitive to the minor concentrations of impurities present on the surface of particle. Generally, fairly good correlation between the isoelectric point (pH iep ) and point of zero charge

  14. 9% Cr steel high temperature oxidation. Solutions investigated for improving corrosion resistance of the steel

    Energy Technology Data Exchange (ETDEWEB)

    Evin, Harold Nicolas; Heintz, Olivier; Chevalier, Sebastien [UMR 5209 CNRS-Bourgogne Univ. (France). Lab. Interdisciplinaire Carnot de Bourgogne; Foejer, Cecilia; Jakani, Saad; Dhont, Annick; Claessens, Serge [OCAS N.V. ArcelorMittal Global R and D, Gent (Belgium)

    2010-07-01

    The improvement of high temperature oxidation resistance of low chromium content steels, such as T/P91, is of great interest in regards with their application in thermal power generating plants. Indeed, they possess good creep properties, but are facing their limits of use at temperature higher than 600 C, due to accelerated corrosion phenomena. Good knowledge of the mechanisms involved during their oxidation process is needed to prevent the degradation of the materials and to extend life time of the power plants components. Oxide layers thermally grown, on 9% Cr steels (provided by OCAS N.V), during isothermal tests between 600 C and 750 C in laboratory air under atmospheric pressure were investigated, by Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). The oxidation behaviour appeared very limited at 750 C, due to the presence of a breakaway, which can be linked to iron porous oxide grown over the surface of the samples. ''In situ'' X-ray Photoelectron spectroscopy (XPS) analyses were performed in air at 600 C after short exposures (between 5 min and 25 h). A complex mixture of iron oxide, Cr{sub 2}O{sub 3} and Cr (VI) species were characterized in the scales. The in-situ analyses were compared and related to XPS analyses performed on thick oxide scales formed on samples oxidized in air at 600 C for 100h. An oxidation mechanism is then proposed to understand the oxide scale growth in the temperature range 600 - 750 C. The second step of this study consists in improving the high temperature corrosion resistance of these steels without modifying their mechanical properties. Thus several solutions were investigated such as MOCVD coatings, pack cementation coatings, and tested in cycle conditions prior. (orig.)

  15. In vivo non-invasive optical imaging of temperature-sensitive co-polymeric nanohydrogel

    Science.gov (United States)

    Chen, Haiyan; Zhang, Jian; Qian, Zhiyu; Liu, Fei; Chen, Xinyang; Hu, Yuzhu; Gu, Yueqing

    2008-05-01

    Assessment of hyperthermia in pathological tissue is a promising strategy for earlier diagnosis of malignant tumors. In this study, temperature-sensitive co-polymeric nanohydrogel poly(N-isopropylacrylamide-co-acrylic acid) (PNIPA-co-AA) was successfully synthesized by the precipitation polymerization method. The diameters of nanohydrogels were controlled to be less than 100 nm. Also the lower critical solution temperature (LCST, 40 °C) was manipulated above physiological temperature after integration of near-infrared (NIR) organic dye (heptamethine cyanine dye, HMCD) within its interior cores. NIR laser light (765 nm), together with sensitive charge coupled device (CCD) cameras, were designed to construct an NIR imaging system. The dynamic behaviors of PNIPA-co-AA-HMCD composites in denuded mice with or without local hyperthermia treatment were real-time monitored by an NIR imager. The results showed that the PNIPA-co-AA-HMCD composites accumulated in the leg treated with local heating and diffused much slower than that in the other leg without heating. The results demonstrated that the temperature-responsive PNIPA-co-AA-HMCD composites combining with an NIR imaging system could be an effective temperature mapping technique, which provides a promising prospect for earlier tumor diagnosis and thermally related therapeutic assessment.

  16. In vivo non-invasive optical imaging of temperature-sensitive co-polymeric nanohydrogel

    International Nuclear Information System (INIS)

    Chen Haiyan; Hu Yuzhu; Zhang Jian; Liu Fei; Chen Xinyang; Gu Yueqing; Qian Zhiyu

    2008-01-01

    Assessment of hyperthermia in pathological tissue is a promising strategy for earlier diagnosis of malignant tumors. In this study, temperature-sensitive co-polymeric nanohydrogel poly(N-isopropylacrylamide-co-acrylic acid) (PNIPA-co-AA) was successfully synthesized by the precipitation polymerization method. The diameters of nanohydrogels were controlled to be less than 100 nm. Also the lower critical solution temperature (LCST, 40 deg. C) was manipulated above physiological temperature after integration of near-infrared (NIR) organic dye (heptamethine cyanine dye, HMCD) within its interior cores. NIR laser light (765 nm), together with sensitive charge coupled device (CCD) cameras, were designed to construct an NIR imaging system. The dynamic behaviors of PNIPA-co-AA-HMCD composites in denuded mice with or without local hyperthermia treatment were real-time monitored by an NIR imager. The results showed that the PNIPA-co-AA-HMCD composites accumulated in the leg treated with local heating and diffused much slower than that in the other leg without heating. The results demonstrated that the temperature-responsive PNIPA-co-AA-HMCD composites combining with an NIR imaging system could be an effective temperature mapping technique, which provides a promising prospect for earlier tumor diagnosis and thermally related therapeutic assessment

  17. High temperature thermodynamics of solutions of oxygen in vanadium, niobium and tantalum

    International Nuclear Information System (INIS)

    Boureau, G.; Gerdanian, P.

    1981-01-01

    The Tian-Calvet microcalorimetric method has been applied to the determination at 1323 K of ΔH(O 2 ), the partial molar enthalpy of mixing of oxygen in vanadium, niobium and tantalum. The present results are in good agreement with earlier studies using e.m.f. techniques. Nevertheless in the first two solutions, ΔH(O 2 ) has been found somewhat more negative than previously reported. The partial molar entropies of mixing have been recalculated. The low values of the excess entropies are explained by a strong increase of the Debye temperature and a decrease of the electronic density of states at the Fermi level as the oxygen content increases. (author)

  18. The study on density change of carbon dioxide seawater solution at high pressure and low temperature

    International Nuclear Information System (INIS)

    Song, Y.; Chen, B.; Nishio, M.; Akai, M.

    2005-01-01

    It has been widely considered that the global warming, induced by the increasing concentration of carbon dioxide and other greenhouse gases in the atmosphere, is an environmental task affecting the world economic development. In order to mitigate the concentration of CO 2 in the atmosphere, the sequestration of carbon dioxide into the ocean had been investigated theoretically and experimentally over the last 10 years. In addition to ocean dynamics, ocean geological, and biological information on large space and long time scales, the physical-chemistry properties of seawater-carbon dioxide system at high pressure (P>5.0 MPa) and lower temperature (274.15 K 3 , which is approximately same with that of carbon dioxide freshwater solution, the slope of which is 0.275 g/cm 3

  19. Effect of Solution Temperature for Al Alloy Anodizing on Cavitation Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung-Jun [Kunsan National University, Kunsan (Korea, Republic of); Lee, Jung Hyung; Kim, Seong Jong [Mokpo National Maritime University, Haeyangdaehak-ro 91, Mokpo (Korea, Republic of)

    2015-06-15

    The commercialization of aluminum had been delayed than other metals because of its high oxygen affinity. Anodizing is a process in which oxide film is formed on the surface of a valve metal in an electrolyte solution by anodic oxidation reaction. Aluminum has thin oxide film on surface but the oxide film is inhomogeneous having a thickness only in the range of several nanometers. Anodizing process increases the thickness of the oxide film significantly. In this study, porous type oxide film was produced on the surface of aluminum in sulfuric acid as a function of electrolyte temperature, and the optimum condition were determined for anodizing film to exhibit excellent cavitation resistance in seawater environment. The result revealed that the oxide film formed at 10 ℃ represented the highest cavitation resistance, while the oxide film formed at 15 ℃ showed the lowest resistance to cavitation in spite of its high hardness.

  20. Evaluation of SCC test methods for Inconel 600 in low temperature aqueous solutions

    International Nuclear Information System (INIS)

    Newman, R.C.; Roberge, R.; Bandy, R.

    1982-04-01

    In late 1981, widespread leakage was encountered in Alloy 600 steam-generator tubing at the Three Mile Island Unit 1 nuclear power plant. The phenomenon was identified as low-temperature intergranular stress-corrosion cracking (SCC) initiated from the inner surfaces of the tubes exposed to the primary coolant. A testing program was initiated to examine the material and environmental factors relevant to these failures, which were found to be associated with sensitization of the material and contamination of the coolant by air and sodium thiosulfate. The test solutions contained 1.3% boric acid with various additions of sulfur compounds and lithium hydroxide. Constant extension rate testing was used as the primary tool to examine environmental effects such as the inhibition of cracking by lithium hydroxide. Important effects of crack-initiation frequency on the specimen potential (and therefore crack velocity) are demonstrated

  1. Surface tension anomalies in room temperature ionic liquids-acetone solutions

    Science.gov (United States)

    Abe, Hiroshi; Murata, Keisuke; Kiyokawa, Shota; Yoshimura, Yukihiro

    2018-05-01

    Surface tension anomalies were observed in room temperature ionic liquid (RTIL)-acetone solutions. The RTILs are 1-alkyl-3-methylimidazorium iodide with [Cnmim][I] in a [Cnmim][I]-x mol% acetone. The maximum value of the surface tension appeared at 40 mol% acetone, although density decreased monotonically with an increase in acetone concentration. A small alkyl chain length effect of the Cnmim+ cations was observed in the surface tension. By the Gibbs adsorption isotherm, it was found that I- anion-mediated surface structure became dominant above 40 mol%. In the different [Cnmim][TFSI]-acetone mixtures, normal decay of the surface tension was observed on the acetone concentration scale, where TFSI- is bis(trifluoromethanesulfonyl)imide.

  2. Effects of minor Si on microstructures and room temperature fracture toughness of niobium solid solution alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Bin, E-mail: kongbin@buaa.edu.cn; Jia, Lina, E-mail: jialina@buaa.edu.cn; Su, Linfen, E-mail: sulinfen@mse.buaa.edu.cn; Guan, Kai, E-mail: guankai@mse.buaa.edu.cn; Weng, Junfei, E-mail: wengjf@mse.buaa.edu.cn; Zhang, Hu, E-mail: zhanghu@buaa.edu.cn

    2015-07-15

    Controlling the elements content in the niobium solid solution (Nb{sub SS}) is significant for the better comprehensive performance of Nb-silicide-based alloys. In this paper, the effects of minor Si on the microstructures and room temperature fracture toughness of Nb–(0/0.5/1/2)Si–27.63Ti–12.92Cr–2.07Al–1.12Hf (at%, unless stated otherwise) solid solution alloys were investigated. The alloys were processed by vacuum arc-casting (AC), and then heat treated (HT) at 1425 °C for 10 h. In HT alloys, Nb{sub SS} grains are refined gradually with the increase of Si content. Meanwhile, the volume fraction of Cr{sub 2}Nb and silicides phases precipitates increases. The fracture toughness of HT alloys decreases at first but then increases in the range of 0 to 2% Si, because it is a combinatorial process of positive and negative effects caused by the addition of Si. The refinement of Nb{sub SS} grains displays positive effect on fracture toughness, while the increase of solid solubility of Si in Nb{sub SS} and brittle Cr{sub 2}Nb and Nb-silicides precipitate phases display negative effect.

  3. Temperature Dependence of Charge Localization in High-Mobility, Solution-Crystallized Small Molecule Semiconductors Studied by Charge Modulation Spectroscopy

    DEFF Research Database (Denmark)

    Meneau, Aurélie Y. B.; Olivier, Yoann; Backlund, Tomas

    2016-01-01

    In solution-processable small molecule semiconductors, the extent of charge carrier wavefunction localization induced by dynamic disorder can be probed spectroscopically as a function of temperature using charge modulation spectroscopy (CMS). Here, it is shown based on combined fi eld-effect tran......In solution-processable small molecule semiconductors, the extent of charge carrier wavefunction localization induced by dynamic disorder can be probed spectroscopically as a function of temperature using charge modulation spectroscopy (CMS). Here, it is shown based on combined fi eld......-effect transistor and CMS measurements as a function of temperature that in certain molecular semiconductors, such as solution-processible pentacene, charge carriers become trapped at low temperatures in environments in which the charges become highly localized on individual molecules, while in some other molecules...

  4. High-temperature superconductivity in solid solutions based on mixed yttrium and barium cuprate

    International Nuclear Information System (INIS)

    Bazuev, G.V.; Kirsanov, N.A.; Makarova, O.V.; Zubkov, V.G.; Shveikin, G.P.

    1990-01-01

    The discovery of high-temperature superconductivity (T c = 30-40 K) in mixed lanthanum and alkaline earth cuprates La 2-x M x CuO 4 , where M = Ba and Ca (1-3) stimulated an extensive search for new superconducting phases based on mixed oxides of these elements. The superconducting transition temperature T c in LnBa 2 Cu 3 O 7-z phases is practically independent of the REE and lies between 90-96 K. The crystal structure of superconducting YBa 2 Cu 3 O 7-z is similar to perovskite, has orthorhombic symmetry (4,5), and is related to the lanthanum barium cuprite tetragonal defect structure La 3 Ba 3 Cu 6 O 14.1 (8). A study of possible solid solutions (SS) based on YBa 2 Cu 3 O 7-z through iso- or heterovalent substitution for Y 3+ and Ba 2+ and of their electrical properties seems warranted. In the present work, the authors report the synthesis, x-ray diffraction study, and specific electric resistivity of SS Y 1-x M x (Ba 1-y M y ') 2 Cu 3 O 7-z , where M = La, Lu, Sc, In, K, Zr, and Ce and M' = Ca, Sr, Mg, K, and La

  5. Porous aluminum room temperature anodizing process in a fluorinated-oxalic acid solution

    Science.gov (United States)

    Dhahri, S.; Fazio, E.; Barreca, F.; Neri, F.; Ezzaouia, H.

    2016-08-01

    Anodizing of aluminum is used for producing porous insulating films suitable for different applications in electronics and microelectronics. Porous-type aluminum films are most simply realized by galvanostatic anodizing in aqueous acidic solutions. The improvement in application of anodizing technique is associated with a substantial reduction of the anodizing voltage at appropriate current densities as well as to the possibility to carry out the synthesis process at room temperature in order to obtain a self-planarizing dielectric material incorporated in array of super-narrow metal lines. In this work, the anodizing of aluminum to obtain porous oxide was carried out, at room temperature, on three different substrates (glass, stainless steel and aluminum), using an oxalic acid-based electrolyte with the addition of a relatively low amount of 0.4 % of HF. Different surface morphologies, from nearly spherical to larger porous nanostructures with smooth edges, were observed by means of scanning electron microscopy. These evidences are explained by considering the formation, transport and adsorption of the fluorine species which react with the Al3+ ions. The behavior is also influenced by the nature of the original substrate.

  6. Room temperature solution processed low dimensional CH3NH3PbI3 NIR detector

    Science.gov (United States)

    Besra, N.; Paul, T.; Sarkar, P. K.; Thakur, S.; Sarkar, S.; Das, A.; Chanda, K.; Sardar, K.; Chattopadhyay, K. K.

    2018-05-01

    Metal halide perovskites have recently drawn immense research interests among the worldwide scientific community due to their excellent light harvesting capabilities and above all, cost effectiveness. These new class of materials have already been used as efficient optoelectronic devices e.g. solar cells, photo detectors, etc. Here in this work, room temperature NIR (near infra red) response of organic-inorganic lead halide perovskite CH3NH3PbI3 (Methylammonium lead tri iodide) nanorods has been studied. A very simple solution process technique has been adopted to synthesize CH3NH3PbI3 nanostructures at room temperature. The NIR exposure upon the sample resulted in a considerable hike in its dark current with very good responsivity (0.37 mA/W). Along with that, a good on-off ratio (41.8) was also obtained when the sample was treated under a pulsed NIR exposure with operating voltage of 2 V. The specific detectivity of the device came in the order of 1010 Jone.

  7. Effects of different oxyanions in solution on the precipitation of jarosite at room temperature.

    Science.gov (United States)

    Yeongkyoo, Kim

    2018-04-09

    The effects of five different oxyanions, AsO 4 , SeO 3 , SeO 4 , MoO 4 , and CrO 4 , on the precipitation of jarosite at room temperature were investigated by X-ray diffraction, scanning electron microscopy, and chemical analysis. Different amounts (2, 5, and 10 mol%) of oxyanions in the starting solution and different aging times (1 h-40 days) were used for the experiment. In the initial stage, only the amorphous phase appears for all samples. With increasing aging time, jarosite and jarosite with oxyanions start precipitating at room temperature with different precipitation rates and crystallinities. Jarosite with AsO 4 shows the lowest precipitation rate and lowest crystallinity. With increasing amounts of oxyanions, the crystallization rate decreases, especially for jarosite with AsO 4 . The jarosite samples with CrO 4 and SeO 4 show the fastest precipitation and highest crystallinities. For the jarosite samples with a low precipitation rate and low crystallinity, the amorphous phase contains high concentrations of oxyanions, probably because of the fast precipitation of the amorphous iron oxyanion phase; however, the phase with fast jarosite precipitation contains fewer oxyanions. The results show that coprecipitation of jarosite can play a more important role in controlling the behavior of CrO 4 than AsO 4 in acid mine drainage. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Cyclic voltammetry of Monel 400 in lithium hydroxide solution at elevated temperatures

    International Nuclear Information System (INIS)

    MacDonald, D.D.

    1976-01-01

    The electrochemistry of Monel 400 in 1 mole/kg -1 LiOH solution at 25, 125 and 250 0 C has been investigated using the technique of cyclic voltammetry. The general electrochemical behaviour is found to most closely approximate to that of the major component, nickel, although expansion of the current scale reveals anodic and cathodic peaks which probably arise from redox processes involving copper. The general similarity to nickel can be rationalized in terms of either the d electron theory for cupronickel alloys or phase separation, the latter being favoured in the present study. At 25 0 C the majority of charge consumed on sweeping the potential in the positive direction is involved in the formation of an oxide film at potentials close to oxygen evolution. This process is no longer observed at 2500C, due to a sharp reduction in the oxygen evolution overpotential with temperature. The majority of charge consumed on cyclic sweeping at this temperature is attributed to active dissolution of the nickel component of the alloy to form HNiO 2 - (or Ni(OH) 3 - ) at potentials slightly positive to the hydrogen evolution region. (author)

  9. Analytical solution of transient temperature in continuous wave end-pumped laser slab: Reduction of temperature distribution and time of thermal response

    Directory of Open Access Journals (Sweden)

    Shibib Khalid S.

    2017-01-01

    Full Text Available An analytical solution of transient 3-D heat equation based on integral transform method is derived. The result are compared with numerical solution, and good agreements are obtained. Minimization of response time and temperature distribution through a laser slab are tested. It is found that the increasing in the lateral convection heat transfer coefficient can significantly reduce the response time and the temperature distribution while no effect on response time is observed when changing pumping profile from Gaussian to top hat beam in spite of the latter reduce the temperature distribution, also it is found that dividing the pumping power between two slab ends might reduce the temperature distribution and it has no effect on thermal response time.

  10. Apparent molal volumes of HMT and TATD in aqueous solutions around the temperature of maximum density of water

    International Nuclear Information System (INIS)

    Clavijo Penagos, J.A.; Blanco, L.H.

    2012-01-01

    Highlights: ►V φ for HMT and TATD in aqueous solutions around the temperature of maximum density of water are reported. ► V φ is linear in m form m = 0.025 for all the aqueous solutions investigated. ► Variation of V ¯ 2 ∞ with T obeys a second grade polynomial trend. ► The solutes are classified as structure breakers according to Hepler’s criterion. - Abstract: Apparent molal volumes V φ have been determined from density measurements for several aqueous solutions of 1,3,5,7-tetraazatricyclo[3.3.1.1(3,7)]decane (HMT) and 1,3,6,8-tetraazatricyclo[4.4.1.1(3,8)]dodecane (TATD) at T = (275.15, 275.65, 276.15, 276.65, 277.15, 277.65 and 278.15) K as function of composition. The infinite dilution partial molar volumes of solutes in aqueous solution are evaluated through extrapolation. Interactions of the solutes with water are discussed in terms of the effect of the temperature on the volumetric properties and the structure of the solutes. The results are interpreted in terms of water structure-breaking or structure forming character of the solutes.

  11. Low temperature solution synthesis of zinc antimonide, manganese antimonide, and strontium ruthenate compounds

    Science.gov (United States)

    Noblitt, Jennifer Lenkner

    2011-12-01

    Increasing energy demands are fueling research in the area of renewable energy and energy storage. In particular, Li-ion batteries and superconducting wires are attractive choices for energy storage. Improving safety, simplifying manufacturing processes, and advancing technology to increase energy storage capacity is necessary to compete with current marketed energy storage devices. These advancements are accomplished through the study of new materials and new morphologies. Increasing dependence on and rising demand for portable electronic devices has continued to drive research in the area of Li-ion batteries. In order to compete with existing batteries and be applicable to future energy needs such as powering hybrid vehicles, the drawbacks of Li-ion batteries must be addressed including (i) low power density, (ii) safety, and (iii) high manufacturing costs. These drawbacks can be addressed through new materials and morphologies for the anode, cathode, and electrolyte. New intermetallic anode materials such as ZnSb, MnSb, and Mn2Sb are attractive candidates to replace graphite, the current industry standard anode material, because they are safer while maintaining comparable theoretical capacity. Electrodeposition is an inexpensive method that could be used for the synthesis of these electrode materials. Direct electrodeposition allows for excellent electrical contact to the current collector without the use of a binder. To successfully electrodeposit zinc and manganese antimonides, metal precursors with excellent solubility in water were needed. To promote solubility, particularly for the antimony precursor, coordinating ligands were added to the deposition bath solutions. This work shows that the choice of coordinating ligand and metal-ligand speciation can alter both the electrochemistry and the film composition. This work focuses on the search for appropriate coordinating ligands, solution pH, and bath temperatures so that high quality films of ZnSb, MnSb, and

  12. Direct measurement of osmotic pressure of glycosaminoglycan solutions by membrane osmometry at room temperature.

    Science.gov (United States)

    Chahine, Nadeen O; Chen, Faye H; Hung, Clark T; Ateshian, Gerard A

    2005-09-01

    Articular cartilage is a hydrated soft tissue composed of negatively charged proteoglycans fixed within a collagen matrix. This charge gradient causes the tissue to imbibe water and swell, creating a net osmotic pressure that enhances the tissue's ability to bear load. In this study we designed and utilized an apparatus for directly measuring the osmotic pressure of chondroitin sulfate, the primary glycosaminoglycan found in articular cartilage, in solution with varying bathing ionic strength (0.015 M, 0.15 M, 0.5 M, 1 M, and 2 M NaCl) at room temperature. The osmotic pressure (pi) was found to increase nonlinearly with increasing chondroitin sulfate concentration and decreasing NaCl ionic bath environment. Above 1 M NaCl, pi changes negligibly with further increases in salt concentration, suggesting that Donnan osmotic pressure is negligible above this threshold, and the resulting pressure is attributed to configurational entropy. Results of the current study were also used to estimate the contribution of osmotic pressure to the stiffness of cartilage based on theoretical and experimental considerations. Our findings indicate that the osmotic pressure resulting from configurational entropy is much smaller in cartilage (based on an earlier study on bovine articular cartilage) than in free solution. The rate of change of osmotic pressure with compressive strain is found to contribute approximately one-third of the compressive modulus (H(A)(eff)) of cartilage (Pi approximately H(A)(eff)/3), with the balance contributed by the intrinsic structural modulus of the solid matrix (i.e., H(A) approximately 2H(A)(eff)/3). A strong dependence of this intrinsic modulus on salt concentration was found; therefore, it appears that proteoglycans contribute structurally to the magnitude of H(A), in a manner independent of osmotic pressure.

  13. Investigations to explore interactions in (polyhydroxy solute + L-ascorbic acid + H2O) solutions at different temperatures: Calorimetric and viscometric approach

    International Nuclear Information System (INIS)

    Banipal, Parampaul K.; Sharma, Mousmee; Aggarwal, Neha; Banipal, Tarlok S.

    2016-01-01

    Highlights: • The hydrophilic-hydrophilic interactions predominate at low temperatures. • Enthalpy change for polyol is less exothermic than its parent saccharide. • Δ dil C o p,2,m values suggest structural increase in presence of L-ascorbic acid. • Solutes act as kosmotropes in L-ascorbic acid (aq) solutions as indicated by dB/dT. - Abstract: Isothermal titration micro-calorimeter has been used to measure the enthalpy change (q) of polyhydroxy solutes [(+)-D-xylose, xylitol, (+)-D-glucose, 2-deoxy-D-glucose, (+)-methyl-α-D-glucopyranoside, and (+)-maltose monohydrate] in water and in (0.05, 0.15, and 0.25) mol·kg −1 L-ascorbic acid (aq) solutions at (288.15, 298.15, 308.15, and 318.15) K. Limiting enthalpies of dilution (Δ dil H°) of these solutes were calculated from heat evolved/absorbed during calorimetric experiments. Further thermodynamic quantities such as limiting enthalpies of dilution of transfer (Δ tr Δ dil H°), change in heat capacity (Δ dil C o p,2,m ), and pair (h AB ) and triplet (h ABB ) enthalpic interaction coefficients were also calculated and used to explore the nature of interactions of solutes with cosolute (L-ascorbic acid). The Jones-Dole viscosity B-coefficients for (+)-D-xylose, xylitol, (+)-D-galactose, galactitol, (+)-D-glucose, 2-deoxy-D-glucose, (+)-methyl-α-D-glucopyranoside, and (+)-maltose monohydrate in water and in (0.05, 0.15, 0.25, and 0.35) mol·kg −1 L-ascorbic acid (aq) solutions have been determined from viscosity (η) data measured over temperature range (288.15–318.15) K and at pressure, P = 101.3 kPa. The temperature dependence of B-coefficients (dB/dT), and viscosity B-coefficients of transfer (Δ tr B) of solutes from water to cosolute have also been estimated. These parameters have been discussed in terms of structure-making (kosmotropic) or -breaking (chaotropic) behavior of solutes.

  14. Effects of solution temperature on localized corrosion of high nickel content stainless steels and nickel in chromated LiBr solution

    International Nuclear Information System (INIS)

    Munoz, A. Igual; Anton, J. Garcia; Guinon, J.L.; Perez Herranz, V.

    2006-01-01

    The potentiodynamic technique has been used to study the general and localized corrosion resistance of high-alloyed stainless steels (UNS N02031 and UNS R20033) and nickel (UNS N02205) at different temperatures (from 25 deg. C to 80 deg. C) in a heavy brine Lithium Bromide solution. The engineering question of concern is the compatibility of the LiBr fluid with the structural materials of refrigeration systems which use absorption technology. The results of potentiodynamic polarization studies indicate excellent corrosion resistance for stainless steels in LiBr solution at room temperature and no big differences at temperatures above 50 deg. C. In the temperature range of 25-80 deg. C, a linear relationship exists between logarithmic of corrosion rate and reciprocal of absolute temperature (Arrhenius plot). The linear plots showed that the mechanism of the corresponding passivation process is the same for the three investigated alloys, essentially due to the presence of nickel. Tests indicated that stainless steels UNS N02031 and UNS R20033 were the most suitable for use to be used in the construction of absorption units for refrigeration purposes

  15. Resistor capacitor, primitive variable solution of buoyant fluid flow within an enclosure with highly temperature dependent viscosity

    Energy Technology Data Exchange (ETDEWEB)

    Burns, S.P. [Texas Univ., Austin, TX (United States); Gianoulakis, S.E. [Sandia National Labs., Albuquerque, NM (United States)

    1995-07-01

    A numerical solution for buoyant natural convection within a square enclosure containing a fluid with highly temperature dependent viscosity is presented. Although the fluid properties employed do not represent any real fluid, the large variation in the fluid viscosity with temperature is characteristic of turbulent flow modeling with eddy-viscosity concepts. Results are obtained using a primitive variable formulation and the resistor method. The results presented include velocity, temperature and pressure distributions within the enclosure as well as shear stress and heat flux distributions along the enclosure walls. Three mesh refinements were employed and uncertainty values are suggested for the final mesh refinement. These solutions are part of a contributed benchmark solution set for the subject problem.

  16. Temperature field due to time-dependent heat sources in a large rectangular grid - Derivation of analytical solution

    International Nuclear Information System (INIS)

    Claesson, J.; Probert, T.

    1996-01-01

    The temperature field in rock due to a large rectangular grid of heat releasing canisters containing nuclear waste is studied. The solution is by superposition divided into different parts. There is a global temperature field due to the large rectangular canister area, while a local field accounts for the remaining heat source problem. The global field is reduced to a single integral. The local field is also solved analytically using solutions for a finite line heat source and for an infinite grid of point sources. The local solution is reduced to three parts, each of which depends on two spatial coordinates only. The temperatures at the envelope of a canister are given by a single thermal resistance, which is given by an explicit formula. The results are illustrated by a few numerical examples dealing with the KBS-3 concept for storage of nuclear waste. 8 refs

  17. Effects of Pregnant Leach Solution Temperature on the Permeability of Gravelly Drainage Layer of Heap Leaching Structures

    Directory of Open Access Journals (Sweden)

    mehdi amini

    2013-12-01

    Full Text Available In copper heap leaching structures, the ore is leached by an acidic solution. After dissolving the ore mineral, the heap is drained off in the acidic solution using a drainage system (consisting of a network of perforated polyethylene pipes and gravelly drainage layers and is, then, transferred to the leaching plant for copper extraction where the copper is extracted and the remaining solution is dripped over the ore heap for re-leaching. In this process, the reaction between the acidic solution and copper oxide ore is exothermal and the pregnant leach solution (PLS, which is drained off the leaching heap, has a higher temperature than the dripped acidic solution. The PLS temperature variations cause some changes in the viscosity and density which affect the gravelly drainage layer's permeability. In this research, a special permeability measuring system was devised for determining the effects of the PLS temperature variations on the permeability coefficient of the gravelly drainage layer of heap leaching structures. The system, consisting of a thermal acid resistant element and a thermocouple, controls the PLS temperature, which helps measure the permeability coefficient of the gravelly drainage layer. The PLS and gravelly drainage layer of Sarcheshmeh copper mine heap leaching structure No. 1 were used in this study. The permeability coefficient of the gravelly soil was measured against the PLS and pure water at temperatures varying between 3°C to 60°C. Also, the viscosity and density of the PLS and pure water were measured at these temperatures and, using existing theoretical relations, the permeability coefficient of the gravel was computed. A comparison between the experimental and theoretical results revealed a good conformity between the two sets of results. Finally, a case (Taft heap leaching structure, Yazd, Iran was studied and its gravelly drainage layer was designed based on the results of the present research.

  18. Catalytic destruction of perchlorate in ferric chloride and hydrochloric acid solution with control of temperature, pressure and chemical reagents

    Science.gov (United States)

    Gu, Baohua; Cole, David R.; Brown, Gilbert M.

    2004-10-05

    A method is described to decompose perchlorate in a FeCl.sub.3 /HCl aqueous solution such as would be used to regenerate an anion exchange resin used to remove perchlorate. The solution is mixed with a reducing agent, preferably an organic alcohol and/or ferrous chloride, and can be heated to accelerate the decomposition of perchlorate. Lower temperatures may be employed if a catalyst is added.

  19. Influence of yeast strain, priming solution and temperature on beer bottle conditioning.

    Science.gov (United States)

    Marconi, Ombretta; Rossi, Serena; Galgano, Fernanda; Sileoni, Valeria; Perretti, Giuseppe

    2016-09-01

    Recently, there has been a significant increase in the number of microbreweries. Usually, craft beers are bottle conditioned; however, few studies have investigated beer refermentation. One of the objectives of this study was to evaluate the impacts of different experimental conditions, specifically yeast strain, priming solution and temperature, on the standard quality attributes, the volatile compounds and the sensory profile of the bottle-conditioned beer. The other aim was to monitor the evolution of volatile compounds and amino acids consumption throughout the refermentation process to check if it is possible to reduce the time necessary for bottle conditioning. The results indicate that the volatile profile was mainly influenced by the strain of yeast, and this may have obscured the possible impacts of the other parameters. Our results also confirm that the two yeast strains showed different metabolic activity, particularly with respect to esters production. Moreover, we found the Safbrew S-33® strain when primed with Siromix® and refermented at 30 °C yielded the fastest formation of higher alcohols while maintaining low production of off-flavours. These results suggest a formulation that may reduce the time needed for bottle conditioning without affecting the quality of the final beer which may simultaneously improve efficiency and economic profits. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  20. Characterization of highly crystalline lead iodide nanosheets prepared by room-temperature solution processing

    Science.gov (United States)

    Frisenda, Riccardo; Island, Joshua O.; Lado, Jose L.; Giovanelli, Emerson; Gant, Patricia; Nagler, Philipp; Bange, Sebastian; Lupton, John M.; Schüller, Christian; Molina-Mendoza, Aday J.; Aballe, Lucia; Foerster, Michael; Korn, Tobias; Niño, Miguel Angel; Perez de Lara, David; Pérez, Emilio M.; Fernandéz-Rossier, Joaquín; Castellanos-Gomez, Andres

    2017-11-01

    Two-dimensional (2D) semiconducting materials are particularly appealing for many applications. Although theory predicts a large number of 2D materials, experimentally only a few of these materials have been identified and characterized comprehensively in the ultrathin limit. Lead iodide, which belongs to the transition metal halides family and has a direct bandgap in the visible spectrum, has been known for a long time and has been well characterized in its bulk form. Nevertheless, studies of this material in the nanometer thickness regime are rather scarce. In this article we demonstrate an easy way to synthesize ultrathin, highly crystalline flakes of PbI2 by precipitation from a solution in water. We thoroughly characterize the produced thin flakes with different techniques ranging from optical and Raman spectroscopy to temperature-dependent photoluminescence and electron microscopy. We compare the results to ab initio calculations of the band structure of the material. Finally, we fabricate photodetectors based on PbI2 and study their optoelectronic properties.

  1. Fabrication of a temperature-responsive and recyclable MoS2 nanocatalyst through composting with poly (N-isopropylacrylamide)

    Science.gov (United States)

    Liu, Yan; Chen, Pengpeng; Nie, Wangyan; Zhou, Yifeng

    2018-04-01

    A temperature-responsive, recyclable nanocatalyst was fabricated by composting the exfoliated molybdenum disulfide (MoS2) nanosheets with poly (N-isopropylacry lamide) (PNIPAM). The structure and morphology of MoS2/PNIPAM nanocatalyst was fully characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Thermogravimetry analysis (TGA), Scanning electron microscope (SEM) and Transmission electron microscopy (TEM). The temperature-responsive properties of the MoS2/PNIPAM nanocatalyst were confirmed by Dynamic Light Scattering (DLS) and Ultraviolet-visible ((UV-vis)) absorption spectroscopy. The catalytic activities of the MoS2/PNIPAM nanocatalyst were studied using the reduction reaction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) as the model reaction. Results showed that the catalytic activity of the MoS2/PNIPAM nanocatalyst could be regulated by temperature. Furthermore, when the temperature went higher than the low critical solution temperature (LCST) of PNIPAM, the MoS2/PNIPAM nanocatalyst tended to aggregated to form bulk materials from homogeneous suspension.

  2. Enthalpies of solution of methylcalix[4]resorcinarene in non-aqueous solvents as a function of concentration and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Riveros, Diana C. [Laboratorio de Termodinamica de Soluciones, Departamento de Quimica, Facultad de Ciencias, Universidad de los Andes, Bogota D.C. (Colombia); Martinez, Fleming [Grupo de Investigaciones Farmaceutico-Fisicoquimicas, Departamento de Farmacia, Facultad de Ciencias, Universidad Nacional de Colombia, Bogota D.C. (Colombia); Vargas, Edgar F., E-mail: edvargas@uniandes.edu.co [Laboratorio de Termodinamica de Soluciones, Departamento de Quimica, Facultad de Ciencias, Universidad de los Andes, Bogota D.C. (Colombia)

    2012-11-20

    Highlights: Black-Right-Pointing-Pointer The solution enthalpies of methylcalix[4]resorcinarene in alcohols have been measured. Black-Right-Pointing-Pointer The solution enthalpies of methylcalix[4]resorcinarene in alcohols are endothermic. Black-Right-Pointing-Pointer Enthalpies of transference are interpreted in terms of proton donor capacity of alcohols. - Abstract: Enthalpies of solution of 2,8,14,20-tetramethyl-4,6,10,12,16,18,22,24-octahydroxyresorci[4]arene in methanol, ethanol and propanol as a function of molal concentration at (288.15, 298.15 and 308.15) K were measured calorimetrically. The enthalpies of solvation were estimated. Using propanol as the referent solvent, transfer properties to other alcohols were also calculated. In addition, temperature dependence of the enthalpy of solution at infinite dilution was also obtained. The data were interpreted in terms of solute-solvent interactions.

  3. Single-Chain Conformation for Interacting Poly(N-isopropylacrylamide in Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Boualem Hammouda

    2015-04-01

    Full Text Available The demixing phase behavior of Poly(N-isopropylacrylamide (PNIPAM aqueous solution is investigated using small-angle neutron scattering. This polymer phase separates upon heating and demixes around 32 °C. The pre-transition temperature range is characterized by two scattering modes; a low-Q (large-scale signal and a high-Q dissolved chains signal. In order to get insight into this pre-transition region, especially the origin of the low-Q (large-scale structure, the zero average contrast method is used in order to isolate single-chain conformations even in the demixing polymers transition region. This method consists of measuring deuterated and non-deuterated polymers dissolved in mixtures of deuterated and non-deuterated water for which the polymer scattering length density matches the solvent scattering length density. A fixed 4% polymer mass fraction is used in a contrast variation series where the d-water/h-water fraction is varied in order to determine the match point. The zero average contrast (match point sample displays pure single-chain scattering with no interchain contributions. Our measurements prove that the large scale structure in this polymer solution is due to a transient polymer network formed through hydrophobic segment-segment interactions. Scattering intensity increases when the temperature gets close to the phase boundary. While the apparent radius of gyration increases substantially at the Lower Critical Solution Temperature (LCST transition due to strong interchain correlation, the single-chain true radius of gyration has been found to decrease slightly with temperature when approaching the transition.

  4. Numerical solution of fully developed heat transfer problem with constant wall temperature and application to isosceles triangle and parabolic ducts

    International Nuclear Information System (INIS)

    Karabulut, Halit; Ipci, Duygu; Cinar, Can

    2016-01-01

    Highlights: • A numerical method has been developed for fully developed flows with constant wall temperature. • The governing equations were transformed to boundary fitted coordinates. • The Nusselt number of parabolic duct has been investigated. • Validation of the numerical method has been made by comparing published data. - Abstract: In motor-vehicles the use of more compact radiators have several advantages such as; improving the aerodynamic form of cars, reducing the weight and volume of the cars, reducing the material consumption and environmental pollutions, and enabling faster increase of the engine coolant temperature after starting to run and thereby improving the thermal efficiency. For the design of efficient and compact radiators, the robust determination of the heat transfer coefficient becomes imperative. In this study the external heat transfer coefficient of the radiator has been investigated for hydrodynamically and thermally fully developed flows in channels with constant wall temperature. In such situation the numerical treatment of the problem results in a trivial solution. To find a non-trivial solution the problem is treated either as an eigenvalue problem or as a thermally developing flow problem. In this study a numerical solution procedure has been developed and the heat transfer coefficients of the fully developed flow in triangular and parabolic air channels were investigated. The governing equations were transformed to boundary fitted coordinates and numerically solved. The non-trivial solution was obtained by means of guessing the temperature of any grid point within the solution domain. The correction of the guessed temperature was performed via smoothing the temperature profile on a line passing through the mentioned grid point. Results were compared with literature data and found to be consistent.

  5. Solubility and solution thermodynamics of 2-methyl-6-nitroaniline in ten organic solvents at elevated temperatures

    International Nuclear Information System (INIS)

    Cong, Yang; Wang, Jian; Du, Cunbin; Han, Shuo; Zhao, Hongkun

    2016-01-01

    Highlights: • Solubility of 2-methyl-6-nitroaniline in ten solvents were determined. • The solubility were correlated with four thermodynamic models. • Standard dissolution enthalpy and excess enthalpy of the solutions were computed. - Abstract: Knowledge of solubility for 2-methyl-6-nitroaniline in different solvents is essential for its purification and further theoretical studies. In this paper, the solid-liquid equilibrium for 2-methyl-6-nitroaniline in ten pure organic solvents (methanol, ethanol, n-propanol, isopropanol, toluene, ethyl acetate, acetonitrile, acetone, cyclohexane and 1,4-dioxane) was established using the isothermal saturation method at temperatures T = (278.15–313.15) K under pressure of 101.2 kPa, and the solubility of 2-methyl-6-nitroaniline in these solvents were determined by a high-performance liquid chromatography (HPLC). In general, the mole fraction solubility followed the following order from high to low in different solvents: 1,4-dioxane (0.1799–0.3390) > acetone (0.1128–0.3010) > ethyl acetate (0.08414–0.2654) > acetonitrile (0.04179–0.2027) > toluene (0.02367–0.1104) > n-propanol (0.01080–0.04514) > ethanol (0.01020–0.04202) > isopropanol (0.008595–0.03763) > methanol (0.007391–0.03198) > cyclohexane (0.001027–0.005617). The modified Apelblat equation, λh equation, Wilson model and NRTL model were employed to correlate the measured solubility data of 2-methyl-6-nitroaniline in the selected solvents. Results indicated that the largest values of RAD and RMSD acquired by the four models were less than 0.76% and 9.13 × 10"−"4, respectively. The modified Apelblat equation provided better results than the other three models. Furthermore, the standard dissolution enthalpy and excess enthalpy of the solutions were computed from the solubility values. The standard dissolution enthalpies vary within the range from (14.88 to 45.57) kJ·mol"−"1 and are all positive, the dissolution process of 2-methyl-6

  6. Determination of Optimal Temperature for Biosorption of Heavy Metal Mixture from Aqueous Solution by Pretreated Biomass of Aspergillus niger

    Directory of Open Access Journals (Sweden)

    Javad Yousefi

    2012-01-01

    Full Text Available Biosorption is a novel technology that uses dead and inactive biomass for removal of heavy metals from aqueous solution. Some parameters such as temperature, contact time, solution pH, initial metal concentration, biosorbent dose and also agitating speed of solution and biosorbent mixing can affect the amount of metal sorption by biosorbent. The aim of this study was to investigate the effects of different treatments of temperatures (25, 35, 45 and 55oC on biosorption of metals mixture in order to determine optimal temperature for more metals removal from aqueous solution. This study uses dead and pretreated biomass of Aspergillus niger with 0.5N NaOH for removal of Zn(II, Co(II and Cd(II. In all temperature treatments and in the case of all of heavy metals, maximum amount of metal sorption and concentration decrease was occurred in first 5 minutes and achieved to equilibrium after 20 minute. The percent of metals sorption show growth trend with temperature increase. Between 4 experimental treatments, 55oC treatment was shown maximum sorption and 25oC was shown minimum sorption amount. The percent of Cr(II sorption was increase from 28.5% in 25oC to 44.7% in 55oC. Also, this increase was from 40% to 58% for Cd(II and from 37.7% to 65.6% for Zn(II. About 60% of increase in sorption by A. niger was due to increase in temperature. Therefore the amount of metals sorption can be increase, only with temperature increase and without any biomass addition.

  7. Influence of pH, temperature and thermal treatment on site corrosion of SAE 304 steel in chlorinated solutions

    International Nuclear Information System (INIS)

    Konrad, I.B.

    1982-01-01

    The electrochemical behaviour and fracture morphology of homogenized and sensitized type SAE 304 stainless steel U bent specimens, in 3% NaCl solution, at pH=2.0 and pH=7.0 both at room temperature and 100 0 C was studied. Polarization curves, galvanostatic and potentiostatic experiments were run. It could be observed that high temperature and low pH favour transgranular cracking and longer sensitization times lower fracture time and tend to give rise to intergranular fracture. Light sensitization can produce transgranular cracking even at room temperature, when the homogenized alloy does not present stress-corrosion cracking for the same condition. (Author) [pt

  8. High temperature solution-nitriding and low-temperature nitriding of AISI 316: Effect on pitting potential and crevice corrosion performance

    DEFF Research Database (Denmark)

    Bottoli, Federico; Jellesen, Morten Stendahl; Christiansen, Thomas Lundin

    2018-01-01

    in a 0.1M NaCl solution and crevice corrosion immersion tests in 3wt% FeCl3 solution were studied before and after the bulk and surface treatments.Nitrogen addition in the bulk proved to have a beneficial effect on the pitting resistance of the alloy. The formation of a zone of expanded austenite...... at the material surface through low-temperature nitriding resulted in a considerable improvement of the pitting potential and the crevice corrosion performance of the steels....

  9. The effect of temperature on nascent morphology of polyethylene polymerized over solution-phase flat model catalysts

    NARCIS (Netherlands)

    Jiang, S.D.; Kong, B.L.; Han, W.; Thune, P.C.; Yang, X.Z.; Loos, J.; Yan, S.K.

    2009-01-01

    The structure and morphology of polyethylene (PE) produced during solution polymerization using bis(imino)pyridyl metal catalysts supported by flat SiO2/Si(100) wafers were investigated by atomic force microscopy (AFM) and electron diffraction. Depending on the polymerization temperature, ranging

  10. Facile room-temperature solution-phase synthesis of a spherical covalent organic framework for high-resolution chromatographic separation.

    Science.gov (United States)

    Yang, Cheng-Xiong; Liu, Chang; Cao, Yi-Meng; Yan, Xiu-Ping

    2015-08-07

    A simple and facile room-temperature solution-phase synthesis was developed to fabricate a spherical covalent organic framework with large surface area, good solvent stability and high thermostability for high-resolution chromatographic separation of diverse important industrial analytes including alkanes, cyclohexane and benzene, α-pinene and β-pinene, and alcohols with high column efficiency and good precision.

  11. Structure and dynamics of POPC bilayers in water solutions of room temperature ionic liquids

    International Nuclear Information System (INIS)

    Benedetto, Antonio; Bingham, Richard J.; Ballone, Pietro

    2015-01-01

    Molecular dynamics simulations in the NPT ensemble have been carried out to investigate the effect of two room temperature ionic liquids (RTILs), on stacks of phospholipid bilayers in water. We consider RTIL compounds consisting of chloride ([bmim][Cl]) and hexafluorophosphate ([bmim][PF 6 ]) salts of the 1-buthyl-3-methylimidazolium ([bmim] + ) cation, while the phospholipid bilayer is made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). Our investigations focus on structural and dynamical properties of phospholipid and water molecules that could be probed by inelastic and quasi-elastic neutron scattering measurements. The results confirm the fast incorporation of [bmim] + into the lipid phase already observed in previous simulations, driven by the Coulomb attraction of the cation for the most electronegative oxygens in the POPC head group and by sizeable dispersion forces binding the neutral hydrocarbon tails of [bmim] + and of POPC. The [bmim] + absorption into the bilayer favours the penetration of water into POPC, causes a slight but systematic thinning of the bilayer, and further stabilises hydrogen bonds at the lipid/water interface that already in pure samples (no RTIL) display a lifetime much longer than in bulk water. On the other hand, the effect of RTILs on the diffusion constant of POPC (D POPC ) does not reveal a clearly identifiable trend, since D POPC increases upon addition of [bmim][Cl] and decreases in the [bmim][PF 6 ] case. Moreover, because of screening, the electrostatic signature of each bilayer is only moderately affected by the addition of RTIL ions in solution. The analysis of long wavelength fluctuations of the bilayers shows that RTIL sorption causes a general decrease of the lipid/water interfacial tension and bending rigidity, pointing to the destabilizing effect of RTILs on lipid bilayers

  12. Structure and dynamics of POPC bilayers in water solutions of room temperature ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Benedetto, Antonio [School of Physics, University College Dublin, Dublin 4 (Ireland); Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen (Switzerland); Bingham, Richard J. [York Centre for Complex Systems Analysis, University of York, York YO10 5GE (United Kingdom); Ballone, Pietro [Center for Life Nano Science @Sapienza, Istituto Italiano di Tecnologia (IIT), 00185 Roma (Italy); Department of Physics, Università di Roma “La Sapienza,” 00185 Roma (Italy)

    2015-03-28

    Molecular dynamics simulations in the NPT ensemble have been carried out to investigate the effect of two room temperature ionic liquids (RTILs), on stacks of phospholipid bilayers in water. We consider RTIL compounds consisting of chloride ([bmim][Cl]) and hexafluorophosphate ([bmim][PF{sub 6}]) salts of the 1-buthyl-3-methylimidazolium ([bmim]{sup +}) cation, while the phospholipid bilayer is made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). Our investigations focus on structural and dynamical properties of phospholipid and water molecules that could be probed by inelastic and quasi-elastic neutron scattering measurements. The results confirm the fast incorporation of [bmim]{sup +} into the lipid phase already observed in previous simulations, driven by the Coulomb attraction of the cation for the most electronegative oxygens in the POPC head group and by sizeable dispersion forces binding the neutral hydrocarbon tails of [bmim]{sup +} and of POPC. The [bmim]{sup +} absorption into the bilayer favours the penetration of water into POPC, causes a slight but systematic thinning of the bilayer, and further stabilises hydrogen bonds at the lipid/water interface that already in pure samples (no RTIL) display a lifetime much longer than in bulk water. On the other hand, the effect of RTILs on the diffusion constant of POPC (D{sub POPC}) does not reveal a clearly identifiable trend, since D{sub POPC} increases upon addition of [bmim][Cl] and decreases in the [bmim][PF{sub 6}] case. Moreover, because of screening, the electrostatic signature of each bilayer is only moderately affected by the addition of RTIL ions in solution. The analysis of long wavelength fluctuations of the bilayers shows that RTIL sorption causes a general decrease of the lipid/water interfacial tension and bending rigidity, pointing to the destabilizing effect of RTILs on lipid bilayers.

  13. High-temperature x-ray diffraction study of HfTiO4-HfO2 solid solutions

    International Nuclear Information System (INIS)

    Carpenter, D.A.

    1975-01-01

    High-temperature x-ray diffraction techniques were used to determine the axial thermal expansion curves of HfTiO 4 -HfO 2 solid solutions as a function of composition. Data show increasing anisotropy with increasing HfO 2 content. An orthorhombic-to-monoclinic phase transformation was detected near room temperature for compositions near the high HfO 2 end of the orthorhombic phase field and for compositions within the two-phase region (HfTiO 4 solid solution plus HfO 2 solid solution). An orthorhombic-to-cubic phase transformation is indicated by data from oxygen-deficient materials at greater than 1873 0 K. (U.S.)

  14. High-Pressure-High-Temperature Processing Reduces Maillard Reaction and Viscosity in Whey Protein-Sugar Solutions.

    Science.gov (United States)

    Avila Ruiz, Geraldine; Xi, Bingyan; Minor, Marcel; Sala, Guido; van Boekel, Martinus; Fogliano, Vincenzo; Stieger, Markus

    2016-09-28

    The aim of the study was to determine the influence of pressure in high-pressure-high-temperature (HPHT) processing on Maillard reactions and protein aggregation of whey protein-sugar solutions. Solutions of whey protein isolate containing either glucose or trehalose at pH 6, 7, and 9 were treated by HPHT processing or conventional high-temperature (HT) treatments. Browning was reduced, and early and advanced Maillard reactions were retarded under HPHT processing at all pH values compared to HT treatment. HPHT induced a larger pH drop than HT treatments, especially at pH 9, which was not associated with Maillard reactions. After HPHT processing at pH 7, protein aggregation and viscosity of whey protein isolate-glucose/trehalose solutions remained unchanged. It was concluded that HPHT processing can potentially improve the quality of protein-sugar-containing foods, for which browning and high viscosities are undesired, such as high-protein beverages.

  15. Influence of the temperature, volume and type of solution in the mercury vaporization of dental amalgam residue

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Raquel dalla [Department of Chemical Engineering, State University of Maringa, Maringa - PR (Brazil)], E-mail: raqueldc_eng@yahoo.com.br; Cossich, Eneida Sala; Tavares, Celia Regina Granhen [Department of Chemical Engineering, State University of Maringa, Maringa - PR (Brazil)

    2008-12-15

    One of the qualitative methods for the identification of mercury vapor is what it occurs as a way of chemical reaction between palladium chloride and metallic mercury. Palladium chloride ribbons with yellowish coloration put in contact with the vaporized mercury of dental amalgam residue, liberates palladium and forms mercury chloride in your surface, and starts to have black coloration; this form identify the presence of the mercury vapor in the system. This work studies the influence of temperature, volume and type of barrier-solution in the vaporization of mercury during the period of storage of dental amalgam residues, aiming to establish the best conditions for storage of these residues. It was found that for all tested solutions, the longest storage times without any occurrence of mercury vaporization were obtained in the lowest temperatures tested and the largest solution volumes of barrier-solution. The radiographic effluent presented bigger efficacy in the reduction of the volatilization, increasing the period when the residue was stored, however the analysis of this solution after the vaporization test showed the presence of organic mercury. These results show that water is the most efficient barrier against the vaporization of mercury, since it did not result in organic mercury formation in the effluent solution from the storage process.

  16. Influence of the temperature, volume and type of solution in the mercury vaporization of dental amalgam residue

    International Nuclear Information System (INIS)

    Costa, Raquel dalla; Cossich, Eneida Sala; Tavares, Celia Regina Granhen

    2008-01-01

    One of the qualitative methods for the identification of mercury vapor is what it occurs as a way of chemical reaction between palladium chloride and metallic mercury. Palladium chloride ribbons with yellowish coloration put in contact with the vaporized mercury of dental amalgam residue, liberates palladium and forms mercury chloride in your surface, and starts to have black coloration; this form identify the presence of the mercury vapor in the system. This work studies the influence of temperature, volume and type of barrier-solution in the vaporization of mercury during the period of storage of dental amalgam residues, aiming to establish the best conditions for storage of these residues. It was found that for all tested solutions, the longest storage times without any occurrence of mercury vaporization were obtained in the lowest temperatures tested and the largest solution volumes of barrier-solution. The radiographic effluent presented bigger efficacy in the reduction of the volatilization, increasing the period when the residue was stored, however the analysis of this solution after the vaporization test showed the presence of organic mercury. These results show that water is the most efficient barrier against the vaporization of mercury, since it did not result in organic mercury formation in the effluent solution from the storage process

  17. Complete Fiber/Copper Cable Solution for Long-Term Temperature and Pressure Measurement in Supercritical Reservoirs and EGS Wells

    Energy Technology Data Exchange (ETDEWEB)

    Pastouret, Alan [Draka Cableteq USA, Inc., North Dighton, MA (United States); Gooijer, Frans [Draka Cableteq USA, Inc., North Dighton, MA (United States); Overton, Bob [Draka Cableteq USA, Inc., North Dighton, MA (United States); Jonker, Jan [Draka Cableteq USA, Inc., North Dighton, MA (United States); Curley, Jim [Draka Cableteq USA, Inc., North Dighton, MA (United States); Constantine, Walter [Draka Cableteq USA, Inc., North Dighton, MA (United States); Waterman, Kendall Miller [Draka Cableteq USA, Inc., North Dighton, MA (United States)

    2015-11-13

    High Temperature insulated wire and optical fiber cable is a key enabling technology for the Geothermal Technologies Program (GTP). Without insulated electrical wires and optical fiber, downhole temperature and pressure sensors, flow meters and gauges cannot communicate with the surface. Unfortunately, there are currently no insulated electrical wire or fiber cable constructions capable of surviving for extended periods of deployment in a geothermal well (240-325°C) or supercritical (374°C) reservoir. This has severely hindered engineered reservoir creation, management and utilization, as hot zones and cool water intrusions cannot be understood over time. The lack of a insulated electrical wire and fiber cable solution is a fundamental limitation to the viability of this energy source. The High Temperature Downhole Tools target specification is development of tools and sensors for logging and monitoring wellbore conditions at depths of up to 10,000 meters and temperatures up to 374oC. It well recognized in the industry that no current electronic or fiber cable can be successfully deployed in a well and function successfully for more a few days at temperatures over 240oC. The goal of this project was to raise this performance level significantly. Prysmian Group’s objective in this project was to develop a complete, multi-purpose cable solution for long-term deployment in geothermal wells/reservoirs that can be used with the widest variety of sensors. In particular, the overall project objective was to produce a manufacturable cable design that can perform without serious degradation: • At temperatures up to 374°C; • At pressures up to 220 bar; • In a hydrogen-rich environment; and • For the life of the well (> 5 years). This cable incorporates: • Specialty optical fibers, with specific glass chemistry and high temperature and pressure protective coatings for data communication and distributed temperature and pressure sensing, and • High-temperature

  18. Volumetric properties of glucose in aqueous HCI solutions at temperatures from 278.15 to 318.15 K

    Institute of Scientific and Technical Information of China (English)

    ZHUO Kelei; ZHANG Qiufen; XUAN Xiaopeng; ZHANG Hucheng; WANG Jianji

    2007-01-01

    Densities have been measured for Glucose+HC1 +Water at 10-degree intervals from 278.15 to 318.15 K.The apparent molar volumes (Vφ,G) and standard partial molar volumes (V0φ,G) for Glucose in aqueous solution of 0.2,0.4,0.7,1.1,1.6,2.1 mol.kg-1 HCI have been calculated as well as volumetric interaction parameters (VEG) for Glucose-HC1 in water and standard partial molar expansion coefficients ((e)V0φ,G/(e)T)p.Results show that (1) the apparent molar volume for Glucose in aqueous HC1 solutions increases lineally with increasing molality of Glucose and HC1; (2) V0φ,Gfor Glucose in aqueous HC1 solutions increases lineally with increasing molality of HC1; (3) the volumetric interaction parameters for Glucose-HC1 pair in water are small positive and vary slightly with temperature; (4) the relation between V0φ,G and temperature exists as V0φ,G =α0+α1(T-273.15 K)2/3;(5)values of((e)V0φ,G/(e)T)p are positive and increase as temperatures rise,and at given temperatures decrease slightly with increasing molalities of HC1,indicating that the hydration of glucose decreases with increasing temperature and molality of HCI.These phenomena are interpreted successfully by the structure interaction model.

  19. Temperature and Recognition Dual Responsive Poly(N-Isopropylacrylamide) and Poly(N,N-Dimethylacrylamide) with Adamantyl Side Group.

    Science.gov (United States)

    Dong, Qiujing; Luo, Chunhua; Li, Na; Chi, Jiaxiang; Zhang, Qingqing

    2018-03-22

    A series of copolymers with an adamantyl side group (poly(NIPAM-co-AdMA) and poly(DMAM-co-AdMA)) were prepared by radical copolymerization of N -isopropylacrylamide (NIPAM) and N , N -dimethylacrylamide (DMAM) with a 2-methyl-2-adamantylmethacrylate (AdMA) monomer. The structure and composition of the as-synthesized copolymers were characterized by Fourier transform infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance (¹H NMR) spectroscopy, gel permeation chromatography (GPC), thermogravimetric analysis (TGA), and elemental analysis. Temperature and recognition dual responsivity of the copolymers was investigated by cloud point (T cp ) and dynamic light scattering (DLS), respectively. The results show that the as-synthesized copolymers are a kind of temperature-responsive polymer with a lower critical solution temperature (LCST). T cp was approximately consistent with the critical temperature of intermolecular copolymer association (T ass ) from DLS. For these copolymers, T cp decreases with increasing content of AdMA unit in the copolymers. After the addition of β-cyclodextrins (β-CD), T cp increases, and the increment of T cp values gradually became large with increasing content of AdMA in the copolymers. It is host-guest molecular recognition of β-CD and adamantyl groups that endows the as-synthesized copolymers with recognition-tunable thermosensitivity.

  20. Low-temperature metal-oxide thin-film transistors formed by directly photopatternable and combustible solution synthesis.

    Science.gov (United States)

    Rim, You Seung; Lim, Hyun Soo; Kim, Hyun Jae

    2013-05-01

    We investigated the formation of ultraviolet (UV)-assisted directly patternable solution-processed oxide semiconductor films and successfully fabricated thin-film transistors (TFTs) based on these films. An InGaZnO (IGZO) solution that was modified chemically with benzoylacetone (BzAc), whose chelate rings decomposed via a π-π* transition as result of UV irradiation, was used for the direct patterning. A TFT was fabricated using the directly patterned IGZO film, and it had better electrical characteristics than those of conventional photoresist (PR)-patterned TFTs. In addition, the nitric acid (HNO3) and acetylacetone (AcAc) modified In2O3 (NAc-In2O3) solution exhibited both strong UV absorption and high exothermic reaction. This method not only resulted in the formation of a low-energy path because of the combustion of the chemically modified metal-oxide solution but also allowed for photoreaction-induced direct patterning at low temperatures.

  1. Enthalpies of solution of methylcalix[4]resorcinarene in non-aqueous solvents as a function of concentration and temperature

    International Nuclear Information System (INIS)

    Riveros, Diana C.; Martínez, Fleming; Vargas, Edgar F.

    2012-01-01

    Highlights: ► The solution enthalpies of methylcalix[4]resorcinarene in alcohols have been measured. ► The solution enthalpies of methylcalix[4]resorcinarene in alcohols are endothermic. ► Enthalpies of transference are interpreted in terms of proton donor capacity of alcohols. - Abstract: Enthalpies of solution of 2,8,14,20-tetramethyl-4,6,10,12,16,18,22,24-octahydroxyresorci[4]arene in methanol, ethanol and propanol as a function of molal concentration at (288.15, 298.15 and 308.15) K were measured calorimetrically. The enthalpies of solvation were estimated. Using propanol as the referent solvent, transfer properties to other alcohols were also calculated. In addition, temperature dependence of the enthalpy of solution at infinite dilution was also obtained. The data were interpreted in terms of solute–solvent interactions.

  2. Low-temperature solution-processed zinc oxide field effect transistor by blending zinc hydroxide and zinc oxide nanoparticle in aqueous solutions

    Science.gov (United States)

    Shin, Hyeonwoo; Kang, Chan-mo; Baek, Kyu-Ha; Kim, Jun Young; Do, Lee-Mi; Lee, Changhee

    2018-05-01

    We present a novel methods of fabricating low-temperature (180 °C), solution-processed zinc oxide (ZnO) transistors using a ZnO precursor that is blended with zinc hydroxide [Zn(OH)2] and zinc oxide hydrate (ZnO • H2O) in an ammonium solution. By using the proposed method, we successfully improved the electrical performance of the transistor in terms of the mobility (μ), on/off current ratio (I on/I off), sub-threshold swing (SS), and operational stability. Our new approach to forming a ZnO film was systematically compared with previously proposed methods. An atomic forced microscopic (AFM) image and an X-ray photoelectron spectroscopy (XPS) analysis showed that our method increases the ZnO crystallite size with less OH‑ impurities. Thus, we attribute the improved electrical performance to the better ZnO film formation using the blending methods.

  3. Temperature dependence of the mechanical properties of equiatomic solid solution alloys with face-centered cubic crystal structures

    International Nuclear Information System (INIS)

    Wu, Z.; Bei, H.; Pharr, G.M.; George, E.P.

    2014-01-01

    Compared to decades-old theories of strengthening in dilute solid solutions, the mechanical behavior of concentrated solid solutions is relatively poorly understood. A special subset of these materials includes alloys in which the constituent elements are present in equal atomic proportions, including the high-entropy alloys of recent interest. A unique characteristic of equiatomic alloys is the absence of “solvent” and “solute” atoms, resulting in a breakdown of the textbook picture of dislocations moving through a solvent lattice and encountering discrete solute obstacles. To clarify the mechanical behavior of this interesting new class of materials, we investigate here a family of equiatomic binary, ternary and quaternary alloys based on the elements Fe, Ni, Co, Cr and Mn that were previously shown to be single-phase face-centered cubic (fcc) solid solutions. The alloys were arc-melted, drop-cast, homogenized, cold-rolled and recrystallized to produce equiaxed microstructures with comparable grain sizes. Tensile tests were performed at an engineering strain rate of 10 −3 s −1 at temperatures in the range 77–673 K. Unalloyed fcc Ni was processed similarly and tested for comparison. The flow stresses depend to varying degrees on temperature, with some (e.g. NiCoCr, NiCoCrMn and FeNiCoCr) exhibiting yield and ultimate strengths that increase strongly with decreasing temperature, while others (e.g. NiCo and Ni) exhibit very weak temperature dependencies. To better understand this behavior, the temperature dependencies of the yield strength and strain hardening were analyzed separately. Lattice friction appears to be the predominant component of the temperature-dependent yield stress, possibly because the Peierls barrier height decreases with increasing temperature due to a thermally induced increase of dislocation width. In the early stages of plastic flow (5–13% strain, depending on material), the temperature dependence of strain hardening is due

  4. Application of the expansion in Maxwellians to the solution of temperature relaxation problems

    International Nuclear Information System (INIS)

    Ender, A.Y.; Ender, I.A.

    1985-01-01

    This paper discusses the temperature relaxation problem: it is assumed that at an initial moment in a spatially uniform rarefied gas the distribution function is given in the form of two Maxwellians with arbitrary temperatures. It is required to determine the velocity distribution function for all moments of time. In the linear version of the problem at the initial time only one Maxwellian is considered whose temperature may differ by any amount from the background temperature. The authors note that in treating temperature relaxation problems it is not sufficient to determine the time dependence of energy assuming that the distribution function is a Maxwellian one at all times

  5. Temperature-dependent solute segregation in dilute Cu-Be under self-ion irradiation: a quantitative revision

    International Nuclear Information System (INIS)

    Koch, R.

    1993-01-01

    A reinvestigation of experimental data on solute precipitation behaviour in a Cu-1.35 at.%Be alloy subjected to Cu-ion irradiation has been carried out with regard to its strong dependence on the irradiation temperature in the range 400-700 K. A rate equation formalism presented in 1985 to describe the defect kinetics via mixed dumbbell formation and diffusion has been modified to take account of the redissolution of precipitated solutes into the matrix due to thermal vacancies. On the basis of the derived model this effect is shown to cause the observed reduction and disappearance of precipitation at high temperatures. Dumbbell dissociation and defect recombination with thermal vacancies become effective at still higher temperatures. The low-temperature decrease in precipitation is explained quantitatively by a marked change from the sink to the recombination case for point-defect annihilation. Moreover the whole temperature regime of precipitation is shown to shift to higher temperatures with increasing displacement rate. Both values of the activation enthalpies for migration and dissociation of the interstitial complex are given by analytical expressions and correspond to earlier estimates. (Author)

  6. Aqueous solutions of proline and NaCl studied by differential scanning calorimetry at subzero temperatures

    DEFF Research Database (Denmark)

    Rasmussen, Peter Have; Jørgensen, Bo; Nielsen, Jette

    1997-01-01

    The hydration properties of proline are studied by differential scanning calorimetry (DSC) in aqueous solutions during freezing to -60 degrees C and subsequent heating to +20 degrees C. The concentration of proline in the freeze concentrated solution was estimated to approximately 50 wt% (w/w) in...... plants and insects living under water stress conditions is discussed. (C) 1997 Elsevier Science B.V....

  7. Analysis and research on promising solutions of low temperature district heating without risk of legionella

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Li, Hongwei; Fog, Jette M.

    2014-01-01

    Most regulations of domestic hot water supply temperature is around 55-60 oC, which potentially requires higher district heating temperature. However, high supply temperature of district heating causes many problems, such as the high heating loss, and obstacles for applying renewable energy...... resources. The most crucial restriction for applying low temperature district heating is the worry about the breakout of legionella, which exists preferably in low temperature hot water systems. Several novel techniques such as electric tracing and flat station were investigated for such dilemma. The pros...... and cons were compared in this paper. Both the energy and economy saving ratios were analysed comparing with high temperature supply scenario. Furthermore, the viability of the applications in different types of buildings for low temperature district heating (LTDH) was also discussed by using dynamic...

  8. Effect of Aging Temperature on Corrosion Behavior of Sintered 17-4 PH Stainless Steel in Dilute Sulfuric Acid Solution

    Science.gov (United States)

    Szewczyk-Nykiel, Aneta; Kazior, Jan

    2017-07-01

    The general corrosion behavior of sintered 17-4 PH stainless steel processed under different processing conditions in dilute sulfuric acid solution at 25 °C was studied by open-circuit potential measurement and potentiodynamic polarization technique. The corrosion resistance was evaluated based on electrochemical parameters, such as polarization resistance, corrosion potential, corrosion current density as well as corrosion rate. The results showed that the precipitation-hardening treatment could significantly improve the corrosion resistance of the sintered 17-4 PH stainless steel in studied environment. As far as the influence of aging temperature on corrosion behavior of the sintered 17-4 PH stainless steel is concerned, polarization resistance and corrosion rate are reduced with increasing aging temperature from 480 up to 500 °C regardless of the temperature of solution treatment. It can be concluded that the highest corrosion resistance in 0.5 M H2SO4 solution exhibits 17-4 PH after solution treatment at 1040 °C followed by aging at 480 °C.

  9. Alternative solutions for inhibiting Legionella in domestic hot water systems based on low-temperature district heating

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Li, Hongwei; Svendsen, Svend

    2015-01-01

    Abstract District heating is a cost-effective way of providing heat to high heat density areas. Low-temperature district heating (LTDH) is a promising way to make district heating more energy-efficient and adaptable to well-insulated buildings with low heating demand in the future. However, one c...... systems. They have the additional benefit of reducing the heat loss of the hot water system. The alternative design solutions both enrich our options for water sanitation and improve the energy efficiency of our energy systems....... concern is the multiplication of Legionella due to insufficient temperature elevation with low-temperature supply. The aim of this study was to find optimal solutions to this dilemma for specific situations. The solutions were of two types: alternative system designs and various methods of sterilization...... methods, thermal treatment, ionization, chlorine, chlorine dioxide, ultraviolet light, photocatalysis and filtration are discussed as the most frequently used methods in hot water systems. The characteristics, efficacy and operation methods of LTDH using the solutions investigated are documented...

  10. Two cloud-point phenomena in tetrabutylammonium perfluorooctanoate aqueous solutions: anomalous temperature-induced phase and structure transitions.

    Science.gov (United States)

    Yan, Peng; Huang, Jin; Lu, Run-Chao; Jin, Chen; Xiao, Jin-Xin; Chen, Yong-Ming

    2005-03-24

    This paper reported the phase behavior and aggregate structure of tetrabutylammonium perfluorooctanoate (TBPFO), determined by differential scanning calorimeter, electrical conductivity, static/dynamic light scattering, and rheology methods. We found that above a certain concentration the TBPFO solution showed anomalous temperature-dependent phase behavior and structure transitions. Such an ionic surfactant solution exhibits two cloud points. When the temperature was increased, the solution turned from a homogeneous-phase to a liquid-liquid two-phase system, then to another homogeneous-phase, and finally to another liquid-liquid two-phase system. In the first homogeneous-phase region, the aggregates of TBPFO were rodlike micelles and the solution was Newtonian fluid. While in the second homogeneous-phase region, the aggregates of TBPFO were large wormlike micelles, and the solution behaved as pseudoplastic fluid that also exhibited viscoelastic behavior. We thought that the first cloud point might be caused by the "bridge" effect of the tetrabutylammonium counterion between the micelles and the second one by the formation of the micellar network.

  11. Analytical solution to convection-radiation of a continuously moving fin with temperature-dependent thermal conductivity

    Directory of Open Access Journals (Sweden)

    Moradi Amir

    2013-01-01

    Full Text Available In this article, the simultaneous convection-radiation heat transfer of a moving fin of variable thermal conductivity is studied. The differential transformation method (DTM is applied for an analytic solution for heat transfer in fin with two different profiles. Fin profiles are rectangular and exponential. The accuracy of analytic solution is validated by comparing it with the numerical solution that is obtained by fourth-order Runge-Kutta method. The analytical and numerical results are shown for different values of the embedding parameters. DTM results show that series converge rapidly with high accuracy. The results indicate that the fin tip temperature increases when ambient temperature increases. Conversely, the fin tip temperature decreases with an increase in the Peclet number, convection-conduction and radiation-conduction parameters. It is shown that the fin tip temperature of the exponential profile is higher than the rectangular one. The results indicate that the numerical data and analytical method are in a good agreement with each other.

  12. Extended shelf life of random donor platelets stored for 7 days in platelet additive solution at different temperatures

    Directory of Open Access Journals (Sweden)

    Tulika Chandra

    2014-08-01

    Full Text Available Background: Platelets are routinely stored in plasma for 5 days at an average temperature of 22°C. In the present study, the shelf life of random donor platelets was extended by storing for 7 days with and without additive solution at temperatures of 22°C, 18°C, and 16°C. Methods: Random donor platelets were stored in 100% plasma and 20%/80% platelet additive solution. The data were compared using paired "t"- test. The confidence limit was kept at 95%, hence a "p" < 0.05 was considered to be statistically significant. Results: Out of total 150 samples, 148 samples were analyzed and 2 were discarded due to the bacterial contamination on day 7 at 22°C without platelet additive solution. A significant difference in platelet count, platelet factor 3 (PF 3, glucose, lactate dehydrogenase (LDH, and platelet aggregation was observed on day 7 (p < 0.001 at 16°C in without platelet additive solution. In platelet additive solution, the mean values of platelet count, platelet distribution width (PDW, LDH, and pH showed no significant difference on day 7 at 22°C, 18°C, and 16°C. Only significant differences were observed in the levels of mean platelet volume (MPV, PF 3, glucose, and platelet aggregation on day 7 (p < 0.001 at 16°C of the storage period. Conclusion: Random donor platelets functions are better maintained in platelet additive solution as compared to plasma at a lower temperature of 18°C but not at 16°C, on the 7 th day.

  13. Effect of Temperature on the Removal of Cesium and Strontium Ions from Aqueous Solutions Using Zeolite A

    International Nuclear Information System (INIS)

    El-Kamash, A.M.; El-Naggar, M.R.; El-Dessouky, M.I.

    2008-01-01

    Ion exchange experiments between synthetic zeolite A and aqueous solutions of cesium and strontium ions were conducted at constant total ion concentrations of 0.1 N and at different temperatures in the range from 25 to 60 degree C. Thermodynamic equilibrium constants, calculated from the corresponding Kielland's plots, were used for the calculation of . δG degree δH degree and δS degree. The obtained data indicated that zeolite A exhibits higher affinity for Cs + and Sr +2 ions from solution than host Na + ions

  14. Quantitative analysis of the calorimetric parameters associated with the temperature induced aggregation of aqueous solutions of polyoxypropylene

    International Nuclear Information System (INIS)

    Armstrong, Jonathan K.; Chowdhry, Babur Z.; Snowden, Martin J.; Dong, Jingfeng; Leharne, Stephen A.

    2003-01-01

    High sensitivity differential scanning calorimetry (HSDSC)--coupled with the application of a previously outlined thermodynamic model [Patterson et al., Langmuir 13 (1997) 2219]--has been used to the obtain thermodynamic parameters that characterise thermal aggregation in aqueous solutions of polyoxypropylene (POP) of molecular mass 1000 g mol -1 over a range of concentrations (2.5-51.5 g dm -3 ). An important aspect of the derived thermodynamic values, which complements previously reported HSDSC data [Armstrong et al., J. Phys. Chem. 99 (1995) 4590], is the elaboration of heat capacity changes which accompany the aggregation transition. The concentration dependence of the POP thermodynamic data, obtained in this investigation, has been established. These observations provide the means for establishing functional relationships between enthalpy and temperature as well as heat capacity and temperature. The parameters describing the quadratic relationship between enthalpy change associated with aggregation and temperature are in close agreement with those describing the linear relationship between heat capacity change and temperature

  15. Temperature and anion responsive self-assembly of ionic liquid block copolymers coating gold nanoparticles

    Science.gov (United States)

    Li, Junbo; Zhao, Jianlong; Wu, Wenlan; Liang, Ju; Guo, Jinwu; Zhou, Huiyun; Liang, Lijuan

    2016-06-01

    In this paper, double hydrophilic ionic liquid block copolymers (ILBCs), poly poly[1-methyl-3-(2-methacryloyloxy propylimidazolium bromine)]- block-(N-isopropylacrylamide) (PMMPImB- b-PNIPAAm) was first synthesized by reversible additionfragmentation chain transfer (RAFT) and then attached on the surface of gold nanoparticles (Au NPs) via a strong gold-sulfur bonding for preparing hybrid nanoparticles (PMMPImB- b-PNIPAAm-@-Au NPs). The hybrid NPs had a three layers micelle-like structure, including a gold core, thermo-responsive inner shell and anion responsive outer corona. The self-assembling behavior of thermal- and anion-response from shell and corona were respectively investigated by change of temperature and addition of (CF3SO2)2N-. The results showed the hybrid NPs retained a stable dispersion beyond the lower critical solution temperature (LCST) because of the space or electrostatic protecting by outer PMMPImB. However, with increasing concentration of (CF3SO2)2N-, the micellization of self-assembling PMMPImB- b-PNIPAAm-@-Au NPs was induced to form micellar structure containing the core with hydrophobic PMMPImB-(CF3SO2)2N- surrounded by composite shell of Au NPs-PNIPAAm via the anionresponsive properties of ILBCs. These results indicated that the block copolymers protected plasmonic nanoparticles remain self-assembling properties of block copolymers when phase transition from outer corona polymer.

  16. Mechanical behaviour of substitutional body centered cubic Fe-Ti solid solutions at temperatures between 77 and 900 K; Plasticite des solutions solides cubiques centrees substitutionnelles fer-titane aux temperatures comprises entre 77 et 900 K

    Energy Technology Data Exchange (ETDEWEB)

    Dubots, Patrick

    1976-05-11

    Plastic behavior of body-centered cubic, interstitial free, Fe-Ti substitutional solid solutions has been characterised. We obtained the following results: at temperatures below 500 K, the thermal component τ* of the critical resolved shear stress τ greatly increases. Solute additions (c >0.12 wt pc) results in: softening at temperatures below 200 K, hardening at temperatures between 200 and 500 K. Results are discussed on Peierls mechanism. At temperatures below 200 K, screw dislocation motion is controlled.by the nucleation of dislocation pairs over the Peierls'hill. Substitutional solute favoring this process gives account of the softening. At temperatures above 200 K, edge dislocation motion controls the strain. The observed hardening is explained by the interaction occurring between edge-dislocations and foreign atoms. At temperatures between 500 and 800 K, a Portevin-Le Chatelier effect is observed. This effect is characterised by two types of serrations. The activation energy of the PLC effect has been determined (E = 1,4 eV). The origin of this phenomenon is the diffusion of solute towards dislocation by a vacancy-mechanism. Two maxima have been observed on the (σ{sub ε} - T) curves. These are due to superposition of overstraining (hardening) and creation of dislocations (softening). The athermal component τ{sub μ} is increased by titanium additions. This hardening has been explained by modulus and size effects. (author) [French] La caracterisation des mecanismes controlant la deformation plastique des solutions solides cubiques centrees substitutionnelles fer-titane, libres d'interstitiels pour les teneurs en solute superieures a 0,12pc pds, a donne les resultats suivants: aux temperatures inferieures a 500 K, la composante thermique τ* de la contrainte critique de cisaillement resolue τ augmente fortement. L'introduction du solute se traduit (pour c>0,12 pc pds): par un adoucissement pour θ < 200 K; par un durcissement pour 200 K< θ < 500 K. Le

  17. Contribution of a solute atoms in the relaxation phenomenon at high temperature in Cu-Al single crystal alloys

    Science.gov (United States)

    Belamri, C.; Belhas, S.; Rivière, A.

    2009-11-01

    Two Cu-Al single crystals with 7 and 14 at. % Al respectively have been studied using isothermal mechanical spectroscopy (IMS) technique. After a 1% cold work by torsion, the samples have been progressively heated to 1140 K and then cooled until room temperature. IMS experiments allow to compare the isothermal internal friction spectra obtained during the heating (in this case, the annealing temperature is equal to the temperature of measurement) with the measurements performed at various temperature during the cooling after the annealing at 1140 K. Three relaxation peaks were observed. The first one at about 0.4 TM (TM: melting point) is a Zener relaxation peak (PZ) due to the reorientation under constraint of pairs of aluminium atoms. The high temperature annealing does not influence PZ. At about 0.6TM, a peak (P1) related to a dislocation mechanism is evidenced. The relaxation strength of P1 peak decreases with the temperature and a new relaxation peak (P2) is progressively developed. The IMS spectra obtained during the cooling evidenced only P2. The relaxation parameters obtained by the Arrhenius plots and the evolution with the annealing temperature allow to assign P1 and P2 to an interaction between the dislocations and the solute atoms according to the Darinskiy model.

  18. 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.

  19. Salt weathering in Egyptian limestone after laboratory simulations with continuous flow of salt solutions at different temperatures

    Science.gov (United States)

    Aly, Nevin; Gomez-Heras, Miguel; Hamed, Ayman; Alvarez de Buergo, Monica

    2013-04-01

    weathering in Egyptian limestone after laboratory simulations with continuous flow of salt solutions at different temperatures Nevin Aly Mohamed (1), Miguel Gomez - Heras(2), Ayman Hamed Ahmed (1), and Monica Alvarez de Buergo(2). (1) Faculty of Pet. & Min. Engineering- Suez Canal University, Suez, Egypt, (2) Instituto de Geociencias (CSIC-UCM) Madrid. Spain. Limestone is one of the most frequent building stones in Egypt and is used since the time of ancient Egyptians and salt weathering is one of the main threats to its conservation. Most of the limestone used in historical monuments in Cairo is a biomicrite extracted from the Mid-Eocene Mokattam Group. During this work, cylindrical samples (2.4 cm diameter and approx. 4.8 cm length) were subjected, in a purpose-made simulation chamber, to simulated laboratory weathering tests with fixed salt concentration (10% weight NaCl solution), at different temperatures, which were kept constant throughout each test (10, 20, 30, 40 oC). During each test, salt solutions flowed continuously imbibing samples by capilarity. Humidity within the simulation chamber was reduced using silica gel to keep it low and constant to increase evaporation rate. Temperature, humidity inside the simulation chamber and samples weight were digitally monitored during each test. Results show the advantages of the proposed experimental methodology using a continuous flow of salt solutions and shed light on the effect of temperature on the dynamics of salt crystallization on and within samples. Research funded by mission sector of high education ministry, Egypt and Geomateriales S2009/MAT-1629.

  20. Closed-form solution of a two-dimensional fuel temperature model for TRIGA-type reactors

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, J B [Sandia Laboratories (United States)

    1974-07-01

    If azimuthal power density variations are ignored, the steady-state temperature distribution within a TRIGA-type fuel element is given by the solution of the Poisson equation in two dimensions (r and z) . This paper presents a closed-form solution of this equation as a function of the axial and radial power density profiles, the conductivity of the U-ZrH, the inlet temperature, specific heat and flow rate of the coolant, and the overall heat transfer coefficient. The method begins with the development of a system of linear ordinary differential equations describing mass and energy balances in the fuel and coolant. From the solution of this system, an expression for the second derivative of the fuel temperature distribution in the axial (z) direction is found. Substitution of this expression into the Poisson equation for T(r,z) reduces it from a partial differential equation to an ordinary differential equation in r, which is subsequently solved in closed-form. The results of typical calculations using the model are presented. (author)

  1. Effect of temperature on solvation behaviour of diclofenac sodium salt in aqueous glycine and L-proline solutions

    International Nuclear Information System (INIS)

    Ryshetti, Suresh; Gardas, Ramesh L; Tangeda, Savitha Jyostna

    2015-01-01

    Highlights: • Solvation behaviour of diclofenac drug studied in aqueous solutions. • Density and speed of sound of drug in aq. glycine and L-proline are measured. • Hydrophobic nature of diclofenac sodium salt is studied. • Effect of temperature on solvation of diclofenac sodium salt is analysed. - Abstract: Apparent molar volume (V 2,ϕ ) and apparent molar isentropic compressibility (K s,2,ϕ ) of diclofenac sodium salt (DSS) drug within the concentration range of (0.001 to 0.008) mol · kg −1 in (0.01, 0.03 and 0.05) mol · kg −1 aqueous glycine and L-proline solutions are computed from the experimental density (ρ) and speed of sound (u) values at T = (293.15 to 313.15) K and atmospheric pressure. Derived parameters such as partial molar properties, transfer partial molar properties, hydration numbers and Hepler’s constant are computed from the data of V 2,ϕ and K s,2,ϕ . These parameters have been used to understand the effect of temperature on interactions between DSS drug and aqueous glycine/L-proline solution. Furthermore, the structure making and breaking ability of DSS drug in probed solutions are analysed at experimental conditions

  2. Temperature prediction in a coal fired boiler with a fixed bed by fuzzy logic based on numerical solution

    International Nuclear Information System (INIS)

    Biyikoglu, A.; Akcayol, M.A.; Oezdemir, V.; Sivrioglu, M.

    2005-01-01

    In this study, steady state combustion in boilers with a fixed bed has been investigated. Temperature distributions in the combustion chamber of a coal fired boiler with a fixed bed are predicted using fuzzy logic based on data obtained from the numerical solution method for various coal and air feeding rates. The numerical solution method and the discretization of the governing equations of two dimensional turbulent flow in the combustion chamber and one dimensional coal combustion in the fixed bed are explained. Control Volume and Finite Difference Methods are used in the discretization of the equations in the combustion chamber and in the fixed bed, respectively. Results are presented as contours within the solution domain and compared with numerical ones. Comparison of the results shows that the difference between the numerical solution and fuzzy logic prediction throughout the computational domain is less than 1.5%. The statistical coefficient of multiple determinations for the investigated cases is about 0.9993 to 0.9998. This accuracy degree is acceptable in predicting the temperature values. So, it can be concluded that fuzzy logic provides a feasible method for defining the system properties

  3. Ultrasonic speed, densities and viscosities of xylitol in water and in aqueous tyrosine and phenylalanine solutions at different temperatures

    Science.gov (United States)

    Ali, A.; Bidhuri, P.; Uzair, S.

    2014-07-01

    Ultrasonic speed u, densities ρ and viscosities η of xylitol in water and in 0.001 m aqueous l-tyrosine (Tyr) and l-phenylalanine (Phe) have been measured at different temperatures. From the density and ultrasonic speed measurements apparent molar isentropic compression κ_{φ}, apparent molar isentropic compressions at infinite dilution κ_{{S,φ}}0 , experimental slope S K , hydration number n H , transfer partial molar isentropic compressibility Δ_{tr} κ_{{S,φ}}0 of xylitol from water to aqueous Tyr and Phe have been obtained. From the viscosity data, B-coefficient and B-coefficient of transfer Δ tr B of xylitol from water to aqueous Phe and Tyr at different temperatures have also been estimated. Gibbs free energies of activation of viscous flow per mole of solvent Δ μ 1 0# and per mole of solute Δ μ 2 0# have been calculated by using Feakins transition state theory for the studied systems. The calculated parameters have been interpreted in terms of solute-solute and solute-solvent interactions and hydration behavior of xylitol.

  4. Volumetric behaviour of amino acids and their group contributions in aqueous lactose solutions at different temperatures

    International Nuclear Information System (INIS)

    Pal, Amalendu; Chauhan, Nalin

    2011-01-01

    Densities, ρ, for glycine, L-alanine, L-valine, and L-leucine [(0.05 to 0.30) m] in aqueous lactose solutions ranging from pure water to 6 mass% lactose were determined at T = (293.15, 298.15, 303.15, and 308.15) K. The density was used to compute apparent molar volume, V φ , partial molar volume at infinite dilution, V φ o , and experimental slope, S V were obtained and interpreted in terms of solute-solvent and solute-solute interactions. These data were used to calculate the (∂V φ 0 /∂T) P values. The partial molar volume of transfer, ΔV φ 0 from water to aqueous lactose solutions at infinite dilution has also been calculated. In addition to this, the linear correlation of V φ 0 with number of carbon atoms in the alkyl chain of amino acids was utilized to determine the respective contributions of NH 3 + COO - , and CH 2 groups to V φ 0 .

  5. Volumetric behaviour of amino acids and their group contributions in aqueous lactose solutions at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Amalendu, E-mail: palchem@sify.co [Department of Chemistry, Kurukshetra University, Kurukshetra 136 119 (India); Chauhan, Nalin [Department of Chemistry, Kurukshetra University, Kurukshetra 136 119 (India)

    2011-02-15

    Densities, {rho}, for glycine, L-alanine, L-valine, and L-leucine [(0.05 to 0.30) m] in aqueous lactose solutions ranging from pure water to 6 mass% lactose were determined at T = (293.15, 298.15, 303.15, and 308.15) K. The density was used to compute apparent molar volume, V{sub {phi}}, partial molar volume at infinite dilution, V{sub {phi}}{sup o}, and experimental slope, S{sub V} were obtained and interpreted in terms of solute-solvent and solute-solute interactions. These data were used to calculate the ({partial_derivative}V{sub {phi}}{sup 0}/{partial_derivative}T){sub P} values. The partial molar volume of transfer, {Delta}V{sub {phi}}{sup 0} from water to aqueous lactose solutions at infinite dilution has also been calculated. In addition to this, the linear correlation of V{sub {phi}}{sup 0} with number of carbon atoms in the alkyl chain of amino acids was utilized to determine the respective contributions of NH{sub 3}{sup +}COO{sup -}, and CH{sub 2} groups to V{sub {phi}}{sup 0}.

  6. Numerical solution of the point reactor kinetics equations with fuel burn-up and temperature feedback

    International Nuclear Information System (INIS)

    Tashakor, S.; Jahanfarnia, G.; Hashemi-Tilehnoee, M.

    2010-01-01

    Point reactor kinetics equations are solved numerically using one group of delayed neutrons and with fuel burn-up and temperature feedback included. To calculate the fraction of one-group delayed neutrons, a group of differential equations are solved by an implicit time method. Using point reactor kinetics equations, changes in mean neutrons density, temperature, and reactivity are calculated in different times during the reactor operation. The variation of reactivity, temperature, and maximum power with time are compared with the predictions by other methods.

  7. Specific features of kinetics of He3-He4 solid solution transformations at superlow temperatures

    International Nuclear Information System (INIS)

    Mikheev, V.A.; Majdanov, V.A.; Mikhin, N.P.

    1986-01-01

    The NMR data on the phase transition kinetics of 3 He- 4 He solid solutions at T=100 mK are considered. Studied are solid helium samples of a molecular volume of 20.55 cm 2 /mol with a 3 He content of 0.54 %. An unusually long phase transition time is found which is dependent on the prehistory of sample. The spin diffusion of 3 He in the transformated solution concentrated phase is found to be of a quasi-one-dimensional nature with the diffusion coefficient value typical of liquid

  8. Measurement of the temperature of density maximum of water solutions using a convective flow technique

    OpenAIRE

    Cawley, M.F.; McGlynn, D.; Mooney, P.A.

    2006-01-01

    A technique is described which yields an accurate measurement of the temperature of density maximum of fluids which exhibit such anomalous behaviour. The method relies on the detection of changes in convective flow in a rectangular cavity containing the test fluid.The normal single-cell convection which occurs in the presence of a horizontal temperature gradient changes to a double cell configuration in the vicinity of the density maximum, and this transition manifests itself in changes in th...

  9. A Harsh Environment Wireless Pressure Sensing Solution Utilizing High Temperature Electronics

    Science.gov (United States)

    Yang, Jie

    2013-01-01

    Pressure measurement under harsh environments, especially at high temperatures, is of great interest to many industries. The applicability of current pressure sensing technologies in extreme environments is limited by the embedded electronics which cannot survive beyond 300 °C ambient temperature as of today. In this paper, a pressure signal processing and wireless transmission module based on the cutting-edge Silicon Carbide (SiC) devices is designed and developed, for a commercial piezoresistive MEMS pressure sensor from Kulite Semiconductor Products, Inc. Equipped with this advanced high-temperature SiC electronics, not only the sensor head, but the entire pressure sensor suite is capable of operating at 450 °C. The addition of wireless functionality also makes the pressure sensor more flexible in harsh environments by eliminating the costly and fragile cable connections. The proposed approach was verified through prototype fabrication and high temperature bench testing from room temperature up to 450 °C. This novel high-temperature pressure sensing technology can be applied in real-time health monitoring of many systems involving harsh environments, such as military and commercial turbine engines. PMID:23447006

  10. Effect of substrate temperature on corrosion performance of nitrogen doped amorphous carbon thin films in NaCl solution

    Energy Technology Data Exchange (ETDEWEB)

    Khun, N.W. [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Liu, E., E-mail: MEJLiu@ntu.edu.s [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2009-07-01

    Nitrogen doped amorphous carbon (a-C:N) thin films were deposited on p-Si substrates by DC magnetron sputtering at varying substrate temperature from room temperature (RT) to 300 {sup o}C. The bonding structure, surface morphology and adhesion strength of the a-C:N films were investigated by using X-ray photoelectron spectroscopy (XPS), micro-Raman spectroscopy, atomic force microscopy (AFM) and micro-scratch testing. The corrosion behavior of the a-C:N films was evaluated by potentiodynamic polarization test in a 0.6 M NaCl solution. The results indicated that the corrosion resistance of the films depended on the sp{sup 3}-bonded cross-link structure that was significantly affected by the substrate temperature.

  11. Effect of substrate temperature on corrosion performance of nitrogen doped amorphous carbon thin films in NaCl solution

    International Nuclear Information System (INIS)

    Khun, N.W.; Liu, E.

    2009-01-01

    Nitrogen doped amorphous carbon (a-C:N) thin films were deposited on p-Si substrates by DC magnetron sputtering at varying substrate temperature from room temperature (RT) to 300 o C. The bonding structure, surface morphology and adhesion strength of the a-C:N films were investigated by using X-ray photoelectron spectroscopy (XPS), micro-Raman spectroscopy, atomic force microscopy (AFM) and micro-scratch testing. The corrosion behavior of the a-C:N films was evaluated by potentiodynamic polarization test in a 0.6 M NaCl solution. The results indicated that the corrosion resistance of the films depended on the sp 3 -bonded cross-link structure that was significantly affected by the substrate temperature.

  12. Effect of temperature on hydration kinetics and polymerization of tricalcium silicate in stirred suspensions of CaO-saturated solutions

    International Nuclear Information System (INIS)

    Grant, Steven A.; Boitnott, Ginger E.; Korhonen, Charles J.; Sletten, Ronald S.

    2006-01-01

    Tricalcium silicate was hydrated at 274, 278, 283, 298, and 313 K in stirred suspensions of saturated CaO solutions under a nitrogen-gas atmosphere until the end of deceleratory period. The suspension conductivities and energy flows were measured continuously. The individual reaction rates for tricalcium silicate dissolution, calcium silicate hydrate precipitation, and calcium hydroxide precipitation were calculated from these measurements. The results suggest that the proportion of tricalcium silicate dissolved was determined by the rate of tricalcium silicate dissolution and the time to very rapid calcium hydroxide precipitation. The time to very rapid calcium hydroxide precipitation was more sensitive to changes in temperature than was the rate of tricalcium silicate dissolution, so that the proportion of tricalcium silicate hydration dissolved by the deceleratory period increased with decreasing temperature. The average chain length of the calcium silicate hydrate ascertained by magic-angle spinning nuclear magnetic resonance spectroscopy increased with increasing temperature

  13. Effect of temperature on the (liquid + liquid) equilibrium for aqueous solution of nonionic surfactant and salt: Experimental and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Foroutan, Masumeh [Physical Chemistry Department, School of Chemistry, College of Science, University of Tehran, 14155-6455 Enghelab Avenue, Tehran (Iran, Islamic Republic of)], E-mail: foroutan@khayam.ut.ac.ir; Heidari, Nosrat; Mohammadlou, Maryam [Chemistry Department, Faculty of Science, Uremia University, Uremia (Iran, Islamic Republic of); Sojahrood, Amin Jafari [Physics Department, Faculty of Science, Uremia University, Uremia (Iran, Islamic Republic of)

    2008-07-15

    The effect of temperature on the (liquid + liquid) equilibrium of the aqueous solution of surfactant polyoxyethylene cetylether (with abbreviation name Brij 58) and diammonium hydrogen phosphate has been investigated at T = (303.15, 313.15, 323.15, and 333.15) K. The Flory-Huggins equation with two electrostatic terms (Debye-Huckle and Pitzer-Debye-Huckle equations) was used to correlate the phase behavior of this system. Good agreement has been found between experimental and calculated data from both models. The results indicated that the enlargement of the two-phase region upon increasing the temperature. Additionally temperature dependency of the parameters of the Flory-Huggins model has been calculated.

  14. Densities of L-Glutamic Acid HCl Drug in Aqueous NaCl and KCl Solutions at Different Temperatures

    Science.gov (United States)

    Ryshetti, Suresh; Raghuram, Noothi; Rani, Emmadi Jayanthi; Tangeda, Savitha Jyostna

    2016-04-01

    Densities (ρ ) of (0.01 to 0.07) {mol}{\\cdot } {kg}^{-1} L-Glutamic acid HCl (L-HCl) drug in water, and in aqueous NaCl and KCl (0.5 and 1.0) {mol}{\\cdot } {kg}^{-1} solutions have been reported as a function of temperature at T = (298.15, 303.15, 308.15, and 313.15) K and atmospheric pressure. The accurate density (ρ ) values are used to estimate the various parameters such as the apparent molar volume (V_{2,{\\upphi }}), the partial molar volume (V2^{∞}), the isobaric thermal expansion coefficient (α 2), the partial molar expansion (E2^{∞}), and Hepler's constant (partial 2V2^{∞}/partial T2)P. The Cosphere overlap model is used to understand the solute-solvent interactions in a ternary mixture (L-HCl drug + NaCl or KCl + water). Hepler's constant (partial 2V2^{∞}/partial T2)_P is utilized to interpret the structure-making or -breaking ability of L-HCl drug in aqueous NaCl and KCl solutions, and the results are inferred that L-HCl drug acts as a structure maker, i.e., kosmotrope in aqueous NaCl solutions and performs as a structure breaker, i.e., chaotrope in aqueous KCl solutions.

  15. Effect of temperature and humidity on electrical properties of organic semiconductor orange dye films deposited from solution

    International Nuclear Information System (INIS)

    Karimov, K.S.; Babadzhanov, A.; Turaeva, M.A.; Marupov, R.; Ahmed, M.M.; Khalid, F.A.; Khan, M.N.; Zakaullah, Kh.; Moiz, S.A.

    2003-01-01

    In this study the effect of temperature and humidity on electrical properties of organic semiconductor orange dye (OD) have been examined. Thin films of OD (C/sub 17/H/sub 17/N/sub 5/O/sub 2/) were deposited from 10 wt. % aqueous solution on gold and conductive glass (SnO/sub 2/) substrates. The films were grown at room temperature under normal gravity conditions, i.e., 1 g and in a spin coater up to an angular speed of 1000 RPM. Two different types of structures: surface Ga/OD/Au and sandwich AVOD/SnO/sub 2/ were fabricated and their DC and low frequency AC characteristics were evaluated for the temperature range 30-70 deg. C at ambient humidity of 50-80 %. It was observed that the sandwich structure of OD films show rectification behavior whilst the conductivity of all devices are temperature and humidity dependent. Observed room temperature activation energy for OD films was 0.30 eV which showed an increase up to 0.51 eV as a function of temperature. It was found that certain sandwich structures are more sensitive to humidity than others and the observed resistance to humidity ratio for Au/OD/Au was 5.4 whereas for Au/OD/Ga samples it was 5.0. (author)

  16. Mean-field solution of the Potts glass near the transition temperature to the ordered phase

    Czech Academy of Sciences Publication Activity Database

    Janiš, Václav; Klíč, Antonín

    2011-01-01

    Roč. 84, č. 6 (2011), "064446-1"-"064446-10" ISSN 1098-0121 Institutional research plan: CEZ:AV0Z10100520 Keywords : Potts glass * hierarchic solutions with replicated spins * continuous replica-symmetry breaking Subject RIV: BE - Theoretical Physics Impact factor: 3.691, year: 2011

  17. Low-Temperature Nitriding of Deformed Austenitic Stainless Steels with Various Nitrogen Contents Obtained by Prior High-Temperature Solution Nitriding

    DEFF Research Database (Denmark)

    Bottoli, Federico; Winther, Grethe; Christiansen, Thomas Lundin

    2016-01-01

    In the past decades, high nitrogen steels (HNS) have been regarded as substitutes for conventional austenitic stainless steels because of their superior mechanical and corrosion properties. However, the main limitation to their wider application is their expensive production process....... As an alternative, high-temperature solution nitriding has been applied to produce HNS from three commercially available stainless steel grades (AISI 304L, AISI 316, and EN 1.4369). The nitrogen content in each steel alloy is varied and its influence on the mechanical properties and the stability of the austenite...... investigated. Both hardness and yield stress increase and the alloys remain ductile. In addition, strain-induced transformation of austenite to martensite is suppressed, which is beneficial for subsequent low-temperature nitriding of the surface of deformed alloys. The combination of high- and low...

  18. Effect of temperature on sequestration of Cu (II) from aqueous solution onto turmeric powder

    International Nuclear Information System (INIS)

    Qayoom, A.

    2010-01-01

    In this work effect of temperature on adsorption of Cu(II) onto turmeric powder was investigated in order to understand sequestrating behavior of turmeric powder. Langmuir, Freundlich and D-R equilibrium models were employed and changes in equilibrium parameters with changing temperature have been discussed. Various thermodynamic parameters such as delta H, delta G and delta S have been calculated. It was found that with increase in temperature maximum adsorption capacities of Cu(II) increase which showed that the adsorption of Cu(II) onto turmeric powder is endothermic. delta H and Ea values also confirmed the same trend. Entropy values showed increased in randomness with increasing temperature. Gibbs free energies were non spontaneous at all the temperatures studied. E values were in the range of 2.89-3.53 KJmol /sup -1/, which indicated that adsorption is essentially of physical nature. The value of S is much less than 1 indicating favourable sticking of adsorbate to adsorbent with physiosorption mechanism predominant. (author)

  19. Low-temperature solution processing of palladium/palladium oxide films and their pH sensing performance.

    Science.gov (United States)

    Qin, Yiheng; Alam, Arif U; Pan, Si; Howlader, Matiar M R; Ghosh, Raja; Selvaganapathy, P Ravi; Wu, Yiliang; Deen, M Jamal

    2016-01-01

    Highly sensitive, easy-to-fabricate, and low-cost pH sensors with small dimensions are required to monitor human bodily fluids, drinking water quality and chemical/biological processes. In this study, a low-temperature, solution-based process is developed to prepare palladium/palladium oxide (Pd/PdO) thin films for pH sensing. A precursor solution for Pd is spin coated onto pre-cleaned glass substrates and annealed at low temperature to generate Pd and PdO. The percentages of PdO at the surface and in the bulk of the electrodes are correlated to their sensing performance, which was studied by using the X-ray photoelectron spectroscope. Large amounts of PdO introduced by prolonged annealing improve the electrode's sensitivity and long-term stability. Atomic force microscopy study showed that the low-temperature annealing results in a smooth electrode surface, which contributes to a fast response. Nano-voids at the electrode surfaces were observed by scanning electron microscope, indicating a reason for the long-term degradation of the pH sensitivity. Using the optimized annealing parameters of 200°C for 48 h, a linear pH response with sensitivity of 64.71±0.56 mV/pH is obtained for pH between 2 and 12. These electrodes show a response time shorter than 18 s, hysteresis less than 8 mV and stability over 60 days. High reproducibility in the sensing performance is achieved. This low-temperature solution-processed sensing electrode shows the potential for the development of pH sensing systems on flexible substrates over a large area at low cost without using vacuum equipment. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Analysis of corrosion data for carbon steels in simulated salt repository brines and acid chloride solutions at high temperatures

    International Nuclear Information System (INIS)

    Diercks, D.R.; Hull, A.B.; Kassner, T.F.

    1988-03-01

    Carbon steel is currently the leading candidate material for fabrication of a container for isolation of high level nuclear waste in a salt repository. Since brine entrapped in the bedded salt can migrate to the container by several transport processes, corrosion is an important consideration in the long-term performance of the waste package. A detailed literature search was performed to compile relevant corrosion data for carbon steels in anoxic acid chloride solutions, and simulated salt repository brines at temperatures between ∼ 20 and 400 0 C. The hydrolysis of Mg 2+ ions in simulated repository brines containing high magnesium concentrations causes acidification at temperatures above 25 0 C, which, in turn, influences the protective nature of the magnetite corrosion product layer on carbon steel. The corrosion data for the steels were analyzed, and an analytical model for general corrosion was developed to calculate the amount of penetration (i.e., wall thinning) as a function of time, temperature, and the pressure of corrosion product hydrogen than can build up during exposure in a closed system (e.g., a sealed capsule). Both the temperature and pressure dependence of the corrosion rate of steels in anoxic acid chloride solutions indicate that the rate-controlling partial reaction is the cathodic reduction of water to form hydrogen. Variations in the composition and microstructure of the steels or the concentration of the ionic species in the chloride solutions (provided that they do not change the pH significantly) do not appear to strongly influence the corrosion rate

  1. Exact solution of thermal radiation on vertical oscillating plate with variable temperature and mass flux

    Directory of Open Access Journals (Sweden)

    Muthucumaraswamy R.

    2010-01-01

    Full Text Available Thermal radiation effects on unsteady flow past an infinite vertical oscillating plate in the presence of variable temperature and uniform mass flux is considered. The fluid considered here is a gray, absorbing-emitting radiation but a non-scattering medium. The plate temperature is raised linearly with time and the mass is diffused from the plate to the fluid at an uniform rate. The dimensionless governing equations are solved using the Laplace transform technique. The velocity, concentration and temperature are studied for different physical parameters like the phase angle, radiation parameter, Schmidt number, thermal Grashof number, mass Grashof number and time. It is observed that the velocity increases with decreasing phase angle ωt.

  2. Temperature dependent structure of the CoFe2O4 colloidal solutions investigated with SANS

    International Nuclear Information System (INIS)

    Balasoiu, M.; Kuklin, A.I.; Grabcev, B.; Bica, D.

    1997-01-01

    We present our preliminary results of the investigation of the modification of the structure of the CoFe 2 O 4 colloids due to the variation of the temperature by means of small angle neutron scattering. The modification of the radius of gyration of the system obtained in the Guinier's approximation, consequently of the hydrodynamic radius, with the variation of the temperature is explained by two phenomena: the Van der Waals attraction between the long tails of the oleic acid molecules adsorbed at the surface of the same particle, determining the surfactant layer to become thinner, and the interpretation of the surfactant shells due to the increasing of the dipole-dipole interaction between the particles with the lowering of the temperature

  3. EXACT SOLUTION FOR TEMPERATURE-DEPENDENT BUCKLING ANALYSIS OF FG-CNT-REINFORCED MINDLIN PLATES

    Directory of Open Access Journals (Sweden)

    Seyed Mohammad Mousavi

    2016-03-01

    Full Text Available This research deals with the buckling analysis of nanocomposite polymeric temperature-dependent plates reinforced by single-walled carbon nanotubes (SWCNTs. For the carbon-nanotube reinforced composite (CNTRC plate, uniform distribution (UD and three types of functionally graded (FG distribution patterns of SWCNT reinforcements are assumed. The material properties of FG-CNTRC plate are graded in the thickness direction and estimated based on the rule of mixture. The CNTRC is located in a elastic medium which is simulated with temperature-dependent Pasternak medium. Based on orthotropic Mindlin plate theory, the governing equations are derived using Hamilton’s principle and solved by Navier method. The influences of the volume fractions of carbon nanotubes, elastic medium, temperature and distribution type of CNTs are considered on the buckling of the plate. Results indicate that CNT distribution close to top and bottom are more efficient than those distributed nearby the mid-plane for increasing the stiffness of plates.

  4. Current sheets with inhomogeneous plasma temperature: Effects of polarization electric field and 2D solutions

    International Nuclear Information System (INIS)

    Catapano, F.; Zimbardo, G.; Artemyev, A. V.; Vasko, I. Y.

    2015-01-01

    We develop current sheet models which allow to regulate the level of plasma temperature and density inhomogeneities across the sheet. These models generalize the classical Harris model via including two current-carrying plasma populations with different temperature and the background plasma not contributing to the current density. The parameters of these plasma populations allow regulating contributions of plasma density and temperature to the pressure balance. A brief comparison with spacecraft observations demonstrates the model applicability for describing the Earth magnetotail current sheet. We also develop a two dimensional (2D) generalization of the proposed model. The interesting effect found for 2D models is the nonmonotonous profile (along the current sheet) of the magnetic field component perpendicular to the current sheet. Possible applications of the model are discussed

  5. Current sheets with inhomogeneous plasma temperature: Effects of polarization electric field and 2D solutions

    Energy Technology Data Exchange (ETDEWEB)

    Catapano, F., E-mail: menacata3@gmail.com; Zimbardo, G. [Dipartimento di Fisica, Università della Calabria, Rende, Cosenza (Italy); Artemyev, A. V., E-mail: ante0226@gmail.com; Vasko, I. Y. [Space Research Institute, RAS, Moscow (Russian Federation)

    2015-09-15

    We develop current sheet models which allow to regulate the level of plasma temperature and density inhomogeneities across the sheet. These models generalize the classical Harris model via including two current-carrying plasma populations with different temperature and the background plasma not contributing to the current density. The parameters of these plasma populations allow regulating contributions of plasma density and temperature to the pressure balance. A brief comparison with spacecraft observations demonstrates the model applicability for describing the Earth magnetotail current sheet. We also develop a two dimensional (2D) generalization of the proposed model. The interesting effect found for 2D models is the nonmonotonous profile (along the current sheet) of the magnetic field component perpendicular to the current sheet. Possible applications of the model are discussed.

  6. Gamma-radiolysis of methanol solutions of Mo(CO)/sub 6/ at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Dziegielewski, J O; Gil, R; Glowacki, P [Uniwersytet Slaski, Katowice (Poland)

    1982-02-04

    Radiation decomposition yields of Mo(CO)/sub 6/ in methanol solutions saturated with argon, N/sub 2/O and in alkaline solutions saturated with argon were measured. The results indicate the interaction of Mo(CO)/sub 6/ with esub(s)sup(-) and CH/sub 2/O/sup -/. The rate constants for these reactions were calculated to be 1.65x10/sup 9/ l x mol/sup -1/ x s/sup -1/ and 2.76x10/sup 7/ l x mol/sup -1/ x s/sup -1/, respectively. On the basis of the spectrophotometrical measurements in the UV-VIS and IR ranges, the stable products of radiolysis were determined.

  7. Corrosion of dissimilar metal crevices in simulated concentrated ground water solutions at elevated temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, B.M.; Quinn, M.J

    2003-01-01

    The disposal of high-level nuclear waste in the Yucca Mountain, Nevada is under consideration by the US Department of Energy. The proposed facility will be located in the unsaturated zone approximately 300 m below the surface and 300 m above the water table. The proposed waste container consists of an outer corrosion-resistant Alloy 22 shell surrounding a 316 NG stainless steel structural inner container that encapsulates the used nuclear fuel waste. A titanium drip shield is proposed to protect the waste container from ground water seepage arid rock-fail. A cycle of dripping/evaporation could result in the generation of concentrated aggressive solutions, which could contact the waste container. The waste container material could be susceptible to crevice corrosion from such solutions. The experiments described in this report support the modeling of waste package degradation processes. The intent was to provide parameter values that are required to model crevice corrosion chemistry, as it relates to hydrogen pick-up, and stress corrosion cracking for selected candidate waste package materials. The purpose of the experiments was to study the crevice corrosion behavior of various candidate materials under near freely corroding conditions and to determine the pH developed in crevice solutions. Experimental results of crevice corrosion of dissimilar metal pairs (Alloy 22, Grade-7 and -16 titanium and 316 stainless steel) immersed in a simulated concentrated ground water at {approx}90{sup o}C are reported. The corrosion potential was measured during exposure periods of between 330 and 630 h. Following the experiments, the pH of the crevice solution was measured. The results indicate that a limited degree of crevice acidification occurred during the experiment. The values for corrosion potential suggest that crevice corrosion may have initiated. The total corrosion was limited, with little visible evidence for crevice corrosion being observed on the sample coupon faces

  8. Temperature-induced phase transition in aqueous solutions of poly(N-isopropylacrylamide)-based block copolymer

    Czech Academy of Sciences Publication Activity Database

    Spěváček, Jiří; Konefal, Rafal; Dybal, Jiří

    2016-01-01

    Roč. 369, č. 1 (2016), s. 92-96 ISSN 1022-1360. [International IUPAC Conference on Polymer-Solvent Complexes and Intercalates /11./ - POLYSOLVAT-11. Kolkata, 27.01.2016-30.01.2016] R&D Projects: GA ČR(CZ) GA15-13853S Institutional support: RVO:61389013 Keywords : aqueous solutions * block copolymers * micelles Subject RIV: CD - Macromolecular Chemistry

  9. Corrosion of dissimilar metal crevices in simulated concentrated ground water solutions at elevated temperature

    International Nuclear Information System (INIS)

    Ikeda, B.M.; Quinn, M.J.

    2003-01-01

    The disposal of high-level nuclear waste in the Yucca Mountain, Nevada is under consideration by the US Department of Energy. The proposed facility will be located in the unsaturated zone approximately 300 m below the surface and 300 m above the water table. The proposed waste container consists of an outer corrosion-resistant Alloy 22 shell surrounding a 316 NG stainless steel structural inner container that encapsulates the used nuclear fuel waste. A titanium drip shield is proposed to protect the waste container from ground water seepage arid rock-fail. A cycle of dripping/evaporation could result in the generation of concentrated aggressive solutions, which could contact the waste container. The waste container material could be susceptible to crevice corrosion from such solutions. The experiments described in this report support the modeling of waste package degradation processes. The intent was to provide parameter values that are required to model crevice corrosion chemistry, as it relates to hydrogen pick-up, and stress corrosion cracking for selected candidate waste package materials. The purpose of the experiments was to study the crevice corrosion behavior of various candidate materials under near freely corroding conditions and to determine the pH developed in crevice solutions. Experimental results of crevice corrosion of dissimilar metal pairs (Alloy 22, Grade-7 and -16 titanium and 316 stainless steel) immersed in a simulated concentrated ground water at ∼90 o C are reported. The corrosion potential was measured during exposure periods of between 330 and 630 h. Following the experiments, the pH of the crevice solution was measured. The results indicate that a limited degree of crevice acidification occurred during the experiment. The values for corrosion potential suggest that crevice corrosion may have initiated. The total corrosion was limited, with little visible evidence for crevice corrosion being observed on the sample coupon faces. The

  10. Electrical properties of solution-deposited ZnO thin-film transistors by low-temperature annealing.

    Science.gov (United States)

    Lim, Chul; Oh, Ji Young; Koo, Jae Bon; Park, Chan Woo; Jung, Soon-Won; Na, Bock Soon; Chu, Hye Yong

    2014-11-01

    Flexible oxide thin-film transistors (Oxide-TFTs) have emerged as next generation transistors because of their applicability in electronic device. In particular, the major driving force behind solution-processed zinc oxide film research is its prospective use in printing for electronics. A low-temperature process to improve the performance of solution-processed n-channel ZnO thin-film transistors (TFTs) fabricated via spin-coating and inkjet-printing is introduced here. ZnO nanoparticles were synthesized using a facile sonochemical method that was slightly modified based on a previously reported method. The influence of the annealing atmosphere on both nanoparticle-based TFT devices fabricated via spin-coating and those created via inkjet printing was investigated. For the inkjet-printed TFTs, the characteristics were improved significantly at an annealing temperature of 150 degrees C. The field effect mobility, V(th), and the on/off current ratios were 3.03 cm2/Vs, -3.3 V, and 10(4), respectively. These results indicate that annealing at 150 degrees C 1 h is sufficient to obtain a mobility (μ(sat)) as high as 3.03 cm2/Vs. Also, the active layer of the solution-based ZnO nanoparticles allowed the production of high-performance TFTs for low-cost, large-area electronics and flexible devices.

  11. Inhibitive effect of N,N'-Dimethylaminoethanol on carbon steel corrosion in neutral sodium chloride solution, at different temperatures

    Directory of Open Access Journals (Sweden)

    Hassoune Mohammed

    2018-01-01

    Full Text Available The inhibition of carbon steel corrosion in neutral sodium chloride solution by N,N'- Dimethylaminoethanol (DMEA, at different temperatures, was investigated using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS techniques. The results obtained confirm that DMEA is a good organic corrosion inhibitor for carbon steel in 0.5M of NaCl (concentration encountered in the Mediterranean seawater, over the whole range of temperatures studied. The inhibition efficiency (IE% increases with increasing DMEA concentration; it reaches highest value for a concentration around 0.125 mol.L-1. Potentiodynamic polarization data show that, the compound studied in this research predominantly act as anodic-type inhibitor. The EIS study reveals that the addition of DMEA decreases the corrosion rate of carbon steel in neutral sodium chloride solution, due to the fact that the inhibitor molecules are strongly adsorbed on the active sites following Langmuir isotherm, thus leading to the formation of a stable protective film on the steel surface which is able to keep the metal/solution interface in a passive state. Furthermore, the values of the activation parameters, i.e. ΔHa and Ea obtained in this study indicate that the adsorption process of DMEA is endothermic and could be mainly attributed to chemisorption, respectively.

  12. Current Problems and Possible Solutions in High-Temperature Lead-Free Soldering

    Czech Academy of Sciences Publication Activity Database

    Kroupa, Aleš; Andersson, D.; Hoo, N.; Pearce, J.; Watson, A.; Dinsdale, A.; Mucklejohn, S.

    2012-01-01

    Roč. 21, č. 5 (2012), s. 629-637 ISSN 1059-9495 Institutional support: RVO:68081723 Keywords : lead-free soldering, * materials for high-temperature LF * new technologies for HT lead-free soldering Subject RIV: BJ - Thermodynamics Impact factor: 0.915, year: 2012

  13. A technique for accurate measurements of temperature variations in solution calorimetry and osmometry of actinide complexes

    International Nuclear Information System (INIS)

    Ponkshe, M.R.; Samuel, J.K.

    1982-01-01

    The temperature variations of the order of 10 3- to 10 -4 C are measured by means of matched pair of thermistors and constant current techniques. The factors deciding the sensitivity and accuracy are fully discussed. Also the factors which put restrictions on the practical detection limits are also described. (author)

  14. Effects of Iodide and Hydrogen Peroxide on Measuring High Temperature pH in Various Lithium Borate Buffer Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Jae Sik; Yun, Myung Hee; Yeon, Jei Won; Song, Kyu Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-10-15

    In a reactor coolant system of nuclear power plants, the need for reliable high temperature pH electrodes has resulted from interests in the corrosion and corrosion product behaviors of the structural materials in a high temperature coolant system. In developing the electrodes for measuring the high temperature pH of aqueous solutions, it is necessary to note two major problems: the chemical stability of an electrode against other chemical impurities, and an electrode's integrity as the temperature and pressure are varied between operational extremes. Over the past decade Macdonald et al. and Danielson et al. have developed many ceramic membrane pH electrodes based on a yttrium stabilized zirconium oxide. However, there are still many experimental difficulties associated with the problems in obtaining electrochemical information across different pressure boundaries and against many kinds of chemical impurities caused by the radiolysis of water and the leakage of a fuel clad. In the present work, we investigated the effects of the environmental factors on a high temperature pH. The selected environmental factors are as follows: system pressure, and chemical species such as iodide and hydrogen peroxide ions.

  15. A high-temperature high-pressure calorimeter for determining heats of solution up to 623 K.

    Science.gov (United States)

    Djamali, Essmaiil; Turner, Peter J; Murray, Richard C; Cobble, James W

    2010-07-01

    A high-temperature high-pressure isoperibol calorimeter for determining the heats of solution and reaction of very dilute substances in water (10(-4) m) at temperatures up to 623 K is described. The energies of vaporization of water at steam saturation pressure were measured as a function of temperature and the results agree with the corresponding values from steam tables to better than 0.08+/-0.18%. The novelties of the present instrument relative to flow type heat capacity calorimeters are that measurements can be made at orders of magnitude lower concentrations and that measurement of heat of reaction involving solids or gases or in the presence of high concentrations of supporting electrolytes, acids, and bases is possible. Furthermore, the advantage of using enthalpy data over heat capacity data for calculations of the standard state Gibbs free energies of electrolytes is that the experimental heat data of this research need only be integrated once to derive higher temperature free energy data from lower temperatures. The derived heat capacities can be used mathematically to obtain free energies by double integration. However, the resulting errors are much smaller than if experimental aqueous heat capacities were used for the integrations.

  16. Higher Temperature Thermal Barrier Coatings with the Combined Use of Yttrium Aluminum Garnet and the Solution Precursor Plasma Spray Process

    Science.gov (United States)

    Gell, Maurice; Wang, Jiwen; Kumar, Rishi; Roth, Jeffery; Jiang, Chen; Jordan, Eric H.

    2018-02-01

    Gas-turbine engines are widely used in transportation, energy and defense industries. The increasing demand for more efficient gas turbines requires higher turbine operating temperatures. For more than 40 years, yttria-stabilized zirconia (YSZ) has been the dominant thermal barrier coating (TBC) due to its outstanding material properties. However, the practical use of YSZ-based TBCs is limited to approximately 1200 °C. Developing new, higher temperature TBCs has proven challenging to satisfy the multiple property requirements of a durable TBC. In this study, an advanced TBC has been developed by using the solution precursor plasma spray (SPPS) process that generates unique engineered microstructures with the higher temperature yttrium aluminum garnet (YAG) to produce a TBC that can meet and exceed the major performance standards of state-of-the-art air plasma sprayed YSZ, including: phase stability, sintering resistance, CMAS resistance, thermal cycle durability, thermal conductivity and erosion resistance. The temperature improvement for hot section gas turbine materials (superalloys & TBCs) has been at the rate of about 50 °C per decade over the last 50 years. In contrast, SPPS YAG TBCs offer the near-term potential of a > 200 °C improvement in temperature capability.

  17. Higher Temperature Thermal Barrier Coatings with the Combined Use of Yttrium Aluminum Garnet and the Solution Precursor Plasma Spray Process

    Science.gov (United States)

    Gell, Maurice; Wang, Jiwen; Kumar, Rishi; Roth, Jeffery; Jiang, Chen; Jordan, Eric H.

    2018-04-01

    Gas-turbine engines are widely used in transportation, energy and defense industries. The increasing demand for more efficient gas turbines requires higher turbine operating temperatures. For more than 40 years, yttria-stabilized zirconia (YSZ) has been the dominant thermal barrier coating (TBC) due to its outstanding material properties. However, the practical use of YSZ-based TBCs is limited to approximately 1200 °C. Developing new, higher temperature TBCs has proven challenging to satisfy the multiple property requirements of a durable TBC. In this study, an advanced TBC has been developed by using the solution precursor plasma spray (SPPS) process that generates unique engineered microstructures with the higher temperature yttrium aluminum garnet (YAG) to produce a TBC that can meet and exceed the major performance standards of state-of-the-art air plasma sprayed YSZ, including: phase stability, sintering resistance, CMAS resistance, thermal cycle durability, thermal conductivity and erosion resistance. The temperature improvement for hot section gas turbine materials (superalloys & TBCs) has been at the rate of about 50 °C per decade over the last 50 years. In contrast, SPPS YAG TBCs offer the near-term potential of a > 200 °C improvement in temperature capability.

  18. Thermodynamic data for iron (II) in high-saline solutions at temperatures up to 90 C

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, Andres G.; Scharge, Tina; Moog, Helge C.

    2013-12-15

    For natural aqueous systems in general and for the near field of underground nuclear waste repositories in particular thermodynamic properties of iron species and solid phases are of predominant importance. Regardless of the question of the host rock, nuclear waste containment in Germany will be based on massive steel canisters. The total mass of iron present in a repository can be, dependent on the applied variant, sum up to more than 100 000 tons. The overall geochemical milieu including pH and EH will be dominated by the overall abundance of metallic, ferrous, and ferric iron, their aqueous speciation and solid iron-phases. This milieu is imposed on all other equilibria of interest, including those which determine radionuclide solubility. In addition to this, iron bearing corrosion phases due to their shear mass may exhibit a significant sink for radionuclides in terms of incorporation or sorption. As to the evolution of EH it is important to note that application of the Nernst equation requires knowing the electrochemical activities of the involved reactants. Iron is present in aqueous solutions in two oxidation states: +II (ferrous iron) and +III (ferric iron). Ferric iron exhibits a much more complex speciation behavior than ferrous iron, where from a conceptual point of view many species may be neglected. Ferric iron, on the contrary, is subject to considerable complex formation with chloride, sulfate, and - most importantly - with hydroxide. For this reason, experimental and theoretical treatment of ''iron'' at GRS in high saline solutions proceeded along two strings, one for each oxidation state, with the ultimate goal to deliver a thermodynamic model for ''iron'' in high saline solutions.

  19. High-temperature thermoelectric properties of the β-As2−xBixTe3 solid solution

    Directory of Open Access Journals (Sweden)

    J.-B. Vaney

    2016-10-01

    Full Text Available Bi2Te3-based compounds are a well-known class of outstanding thermoelectric materials. β-As2Te3, another member of this family, exhibits promising thermoelectric properties around 400 K when appropriately doped. Herein, we investigate the high-temperature thermoelectric properties of the β-As2−xBixTe3 solid solution. Powder X-ray diffraction and scanning electron microscopy experiments showed that a solid solution only exists up to x = 0.035. We found that substituting Bi for As has a beneficial influence on the thermopower, which, combined with extremely low thermal conductivity values, results in a maximum ZT value of 0.7 at 423 K for x = 0.017 perpendicular to the pressing direction.

  20. Stable Inverted Low-Bandgap Polymer Solar Cells with Aqueous Solution Processed Low-Temperature ZnO Buffer Layers

    Directory of Open Access Journals (Sweden)

    Chunfu Zhang

    2016-01-01

    Full Text Available Efficient inverted low-bandgap polymer solar cells with an aqueous solution processed low-temperature ZnO buffer layer have been investigated. The low-bandgap material PTB-7 is employed so that more solar light can be efficiently harvested, and the aqueous solution processed ZnO electron transport buffer layer is prepared at 150°C so that it can be compatible with the roll-to-roll process. Power conversion efficiency (PCE of the inverted device reaches 7.12%, which is near the control conventional device. More importantly, the inverted device shows a better stability, keeping more than 90% of its original PCE after being stored for 625 hours, while PCE of the conventional device is only 75% of what it was. In addition, it is found that the ZnO thin film annealed in N2 can obviously increase PCE of the inverted device further to 7.26%.

  1. Non-dissipative kinetic simulation and analytical solution of three-mode equations of ion temperature gradient instability

    International Nuclear Information System (INIS)

    Watanabe, T.-H.; Sugama, H.; Sato, T.

    1999-12-01

    A non-dissipative drift kinetic simulation scheme, which rigorously satisfies the time-reversibility, is applied to the three-mode coupling problem of the ion temperature gradient (ITG) instability. It is found from the simulation that the three-mode ITG system repeats growth and decay with a period which shows a logarithmic divergence for infinitesimal initial perturbations. Accordingly, time average of the mode amplitude vanishes, as the initial amplitude approaches to zero. An exact solution is analytically given for a class of initial conditions. An excellent agreement is confirmed between the analytical solution and numerical results. The results obtained here provide a useful reference for basic benchmarking of theories and simulation of the ITG modes. (author)

  2. Multigrid solution of the Navier-Stokes equations at low speeds with large temperature variations

    International Nuclear Information System (INIS)

    Sockol, Peter M.

    2003-01-01

    Multigrid methods for the Navier-Stokes equations at low speeds and large temperature variations are investigated. The compressible equations with time-derivative preconditioning and preconditioned flux-difference splitting of the inviscid terms are used. Three implicit smoothers have been incorporated into a common multigrid procedure. Both full coarsening and semi-coarsening with directional fine-grid defect correction have been studied. The resulting methods have been tested on four 2D laminar problems over a range of Reynolds numbers on both uniform and highly stretched grids. Two of the three methods show efficient and robust performance over the entire range of conditions. In addition, none of the methods has any difficulty with the large temperature variations

  3. The influence of temperature on the decomposition kinetics of peracetic acid in solutions

    OpenAIRE

    Kunigk, L.; Gomes, D.R.; Forte, F.; Vidal, K.P.; Gomes, L.F.; Sousa, P.F.

    2001-01-01

    Peracetic acid is a powerful sanitizer that has only recently been introduced in the Brazilian food industry. The main disadvantage of this sanitizer is its decomposition rate. The main purpose of this paper is to present results obtained in experiments carried out to study the decomposition kinetics of peracetic acid in aqueous solutions at 25, 35, 40 and 45 °C. The decompositon of peracetic acid is a first-order reaction. The decomposition rate constants are between 1.71x10-3 h -1 for 25 °C...

  4. Corrosion of titanium alloys in concentrated chloride solutions at temperature up to 160 deg C

    International Nuclear Information System (INIS)

    Ruskol, Yu.S.; Viter, L.I.; Balakin, A.I.; Fokin, M.N.

    1982-01-01

    Resistance of VT1-0 titanium and 4200, 4207 titanium alloys to pitting and total corrosion in chlorides of cadmium, potassium, nickel, ammonium, barium, calcium, lithium, magnesium in respect to pH value and temperature (120,140,160 deg C) is determined. The results obtained are presented as nomograms of stability. Possible reasons for corrosion behaviour of titanium in each of the chlorides are discussed

  5. Determination of Transport Properties From Flowing Fluid Temperature Logging In Unsaturated Fractured Rocks: Theory And Semi-Analytical Solution

    International Nuclear Information System (INIS)

    Mukhopadhyay, Sumit; Tsang, Yvonne W.

    2008-01-01

    Flowing fluid temperature logging (FFTL) has been recently proposed as a method to locate flowing fractures. We argue that FFTL, backed up by data from high-precision distributed temperature sensors, can be a useful tool in locating flowing fractures and in estimating the transport properties of unsaturated fractured rocks. We have developed the theoretical background needed to analyze data from FFTL. In this paper, we present a simplified conceptualization of FFTL in unsaturated fractured rock, and develop a semianalytical solution for spatial and temporal variations of pressure and temperature inside a borehole in response to an applied perturbation (pumping of air from the borehole). We compare the semi-analytical solution with predictions from the TOUGH2 numerical simulator. Based on the semi-analytical solution, we propose a method to estimate the permeability of the fracture continuum surrounding the borehole. Using this proposed method, we estimated the effective fracture continuum permeability of the unsaturated rock hosting the Drift Scale Test (DST) at Yucca Mountain, Nevada. Our estimate compares well with previous independent estimates for fracture permeability of the DST host rock. The conceptual model of FFTL presented in this paper is based on the assumptions of single-phase flow, convection-only heat transfer, and negligible change in system state of the rock formation. In a sequel paper (Mukhopadhyay et al., 2008), we extend the conceptual model to evaluate some of these assumptions. We also perform inverse modeling of FFTL data to estimate, in addition to permeability, other transport parameters (such as porosity and thermal conductivity) of unsaturated fractured rocks

  6. Beyond temperature: Clumped isotope signatures in dissolved inorganic carbon species and the influence of solution chemistry on carbonate mineral composition

    Science.gov (United States)

    Tripati, Aradhna K.; Hill, Pamela S.; Eagle, Robert A.; Mosenfelder, Jed L.; Tang, Jianwu; Schauble, Edwin A.; Eiler, John M.; Zeebe, Richard E.; Uchikawa, Joji; Coplen, Tyler B.; Ries, Justin B.; Henry, Drew

    2015-01-01

    “Clumped-isotope” thermometry is an emerging tool to probe the temperature history of surface and subsurface environments based on measurements of the proportion of 13C and 18O isotopes bound to each other within carbonate minerals in 13C18O16O22- groups (heavy isotope “clumps”). Although most clumped isotope geothermometry implicitly presumes carbonate crystals have attained lattice equilibrium (i.e., thermodynamic equilibrium for a mineral, which is independent of solution chemistry), several factors other than temperature, including dissolved inorganic carbon (DIC) speciation may influence mineral isotopic signatures. Therefore we used a combination of approaches to understand the potential influence of different variables on the clumped isotope (and oxygen isotope) composition of minerals.We conducted witherite precipitation experiments at a single temperature and at varied pH to empirically determine 13C-18O bond ordering (Δ47) and δ18O of CO32- and HCO3- molecules at a 25 °C equilibrium. Ab initio cluster models based on density functional theory were used to predict equilibrium 13C-18O bond abundances and δ18O of different DIC species and minerals as a function of temperature. Experiments and theory indicate Δ47 and δ18O compositions of CO32- and HCO3- ions are significantly different from each other. Experiments constrain the Δ47-δ18O slope for a pH effect (0.011 ± 0.001; 12 ⩾ pH ⩾ 7). Rapidly-growing temperate corals exhibit disequilibrium mineral isotopic signatures with a Δ47-δ18O slope of 0.011 ± 0.003, consistent with a pH effect.Our theoretical calculations for carbonate minerals indicate equilibrium lattice calcite values for Δ47 and δ18O are intermediate between HCO3− and CO32−. We analyzed synthetic calcites grown at temperatures ranging from 0.5 to 50 °C with and without the enzyme carbonic anhydrase present. This enzyme catalyzes oxygen isotopic exchange between DIC species and is present in many

  7. Beyond temperature: Clumped isotope signatures in dissolved inorganic carbon species and the influence of solution chemistry on carbonate mineral composition

    Science.gov (United States)

    Tripati, Aradhna K.; Hill, Pamela S.; Eagle, Robert A.; Mosenfelder, Jed L.; Tang, Jianwu; Schauble, Edwin A.; Eiler, John M.; Zeebe, Richard E.; Uchikawa, Joji; Coplen, Tyler B.; Ries, Justin B.; Henry, Drew

    2015-10-01

    ;Clumped-isotope; thermometry is an emerging tool to probe the temperature history of surface and subsurface environments based on measurements of the proportion of 13C and 18O isotopes bound to each other within carbonate minerals in 13C18O16O22- groups (heavy isotope ;clumps;). Although most clumped isotope geothermometry implicitly presumes carbonate crystals have attained lattice equilibrium (i.e., thermodynamic equilibrium for a mineral, which is independent of solution chemistry), several factors other than temperature, including dissolved inorganic carbon (DIC) speciation may influence mineral isotopic signatures. Therefore we used a combination of approaches to understand the potential influence of different variables on the clumped isotope (and oxygen isotope) composition of minerals. We conducted witherite precipitation experiments at a single temperature and at varied pH to empirically determine 13C-18O bond ordering (Δ47) and δ18O of CO32- and HCO3- molecules at a 25 °C equilibrium. Ab initio cluster models based on density functional theory were used to predict equilibrium 13C-18O bond abundances and δ18O of different DIC species and minerals as a function of temperature. Experiments and theory indicate Δ47 and δ18O compositions of CO32- and HCO3- ions are significantly different from each other. Experiments constrain the Δ47-δ18O slope for a pH effect (0.011 ± 0.001; 12 ⩾ pH ⩾ 7). Rapidly-growing temperate corals exhibit disequilibrium mineral isotopic signatures with a Δ47-δ18O slope of 0.011 ± 0.003, consistent with a pH effect. Our theoretical calculations for carbonate minerals indicate equilibrium lattice calcite values for Δ47 and δ18O are intermediate between HCO3- and CO32-. We analyzed synthetic calcites grown at temperatures ranging from 0.5 to 50 °C with and without the enzyme carbonic anhydrase present. This enzyme catalyzes oxygen isotopic exchange between DIC species and is present in many natural systems. The two

  8. Temperature gradient compatibility tests of some refractory metals and alloys in bismuth and bismuth--lithium solutions

    International Nuclear Information System (INIS)

    DiStefano, J.R.; Cavin, O.B.

    1976-11-01

    Quartz, T-111, and Mo thermal-convection loop tests were conducted at temperatures up to 700 0 C (100 0 C ΔT) to determine the compatibility of several refractory metals/alloys with bismuth and bismuth-lithium solutions for molten salt breeder reactor applications. Methods of evaluation included weight change measurements, metallographic examination, chemical and electron microprobe analysis, and mechanical properties tests. Molybdenum, T-111, and TA--10 percent W appear to be the most promising containment materials, while niobium and iron-based alloys are unacceptable

  9. Effect of alkyl chain length and temperature on the thermodynamic properties of ionic liquids 1-alkyl-3-methylimidazolium bromide in aqueous and non-aqueous solutions at different temperatures

    International Nuclear Information System (INIS)

    Sadeghi, Rahmat; Shekaari, Hemayat; Hosseini, Rahim

    2009-01-01

    The alkyl chain length of 1-alkyl-3-methylimidazolium bromide ([Rmim][Br], R = propyl (C 3 ), hexyl (C 6 ), heptyl (C 7 ), and octyl (C 8 )) was varied to prepare a series of room-temperature ionic liquids (RTILs), and experimental measurements of density and speed of sound at different temperatures ranging from (288.15 to 308.15) K for their aqueous and methanolic solutions in the dilute concentration region (0.01 to 0.30) mol . kg -1 were taken. The values of the compressibilities, expansivity and apparent molar properties for [C n mim][Br] in aqueous and methanolic solutions were determined at the investigated temperatures. The obtained apparent molar volumes and apparent molar isentropic compressibilities were fitted to the Redlich-Mayer and the Pitzer's equations from which the corresponding infinite dilution molar properties were obtained. The values of the infinite dilution molar properties were used to obtain some information about solute-solvent and solute-solute interactions. The thermodynamic properties of investigated ionic liquids in aqueous solutions have been compared with those in methanolic solutions. Also, the comparison between thermodynamic properties of investigated solutions and those of electrolyte solutions, polymer solutions, cationic surfactant solutions and tetraalkylammonium salt solutions have been made

  10. Effect of alkyl chain length and temperature on the thermodynamic properties of ionic liquids 1-alkyl-3-methylimidazolium bromide in aqueous and non-aqueous solutions at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, Rahmat [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)], E-mail: rahsadeghi@yahoo.com; Shekaari, Hemayat [Department of Chemistry, Faculty of Science, University of Mohaghegh Ardabili, Ardabil (Iran, Islamic Republic of); Hosseini, Rahim [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

    2009-02-15

    The alkyl chain length of 1-alkyl-3-methylimidazolium bromide ([Rmim][Br], R = propyl (C{sub 3}), hexyl (C{sub 6}), heptyl (C{sub 7}), and octyl (C{sub 8})) was varied to prepare a series of room-temperature ionic liquids (RTILs), and experimental measurements of density and speed of sound at different temperatures ranging from (288.15 to 308.15) K for their aqueous and methanolic solutions in the dilute concentration region (0.01 to 0.30) mol . kg{sup -1} were taken. The values of the compressibilities, expansivity and apparent molar properties for [C{sub n}mim][Br] in aqueous and methanolic solutions were determined at the investigated temperatures. The obtained apparent molar volumes and apparent molar isentropic compressibilities were fitted to the Redlich-Mayer and the Pitzer's equations from which the corresponding infinite dilution molar properties were obtained. The values of the infinite dilution molar properties were used to obtain some information about solute-solvent and solute-solute interactions. The thermodynamic properties of investigated ionic liquids in aqueous solutions have been compared with those in methanolic solutions. Also, the comparison between thermodynamic properties of investigated solutions and those of electrolyte solutions, polymer solutions, cationic surfactant solutions and tetraalkylammonium salt solutions have been made.

  11. Exact Solutions for Unsteady Free Convection Flow of Casson Fluid over an Oscillating Vertical Plate with Constant Wall Temperature

    Directory of Open Access Journals (Sweden)

    Asma Khalid

    2015-01-01

    Full Text Available The unsteady free flow of a Casson fluid past an oscillating vertical plate with constant wall temperature has been studied. The Casson fluid model is used to distinguish the non-Newtonian fluid behaviour. The governing partial differential equations corresponding to the momentum and energy equations are transformed into linear ordinary differential equations by using nondimensional variables. Laplace transform method is used to find the exact solutions of these equations. Expressions for shear stress in terms of skin friction and the rate of heat transfer in terms of Nusselt number are also obtained. Numerical results of velocity and temperature profiles with various values of embedded flow parameters are shown graphically and their effects are discussed in detail.

  12. A spectroscopic study of uranyl speciation in chloride-bearing solutions at temperatures up to 250 °C

    Science.gov (United States)

    Migdisov, A. A.; Boukhalfa, H.; Timofeev, A.; Runde, W.; Roback, R.; Williams-Jones, A. E.

    2018-02-01

    The speciation of U in NaCl-bearing solutions at temperatures up to 250 °C and concentrations of NaCl up to 1.5 m has been investigated using an in situ spectroscopic technique. The recorded spectra permit us to identify the species present in the solutions as UO22+, UO2Cl+, and UO2Cl2°. UO2Cl3- is also likely present at high temperatures and NaCl concentrations, but concentrations of this species are insufficient for derivation of the formation constants. No evidence was found for species of higher ligand (Cl-) number. Thermodynamic stability constants derived for these species show fair agreement with published data for 25 °C, but differ significantly from those predicted by an earlier high-temperature study (Dargent et al., 2013), which suggested that UO2Cl42- and UO2Cl53- contribute significantly to the mass balance of uranyl chloride complexes, especially at high temperature. In contrast, our data suggest that the main uranyl-chloride complex present in aqueous solutions at T > 150 °C and concentrations of NaCl relevant to natural hydrothermal systems is UO2Cl2°. The values of the logarithms of thermodynamic formation constants (β) for the reaction UO22+ + Cl- = UO2Cl+ are 0.02, 0.25, 0.55, 1.09, 1.59, and 2.28 derived at 25, 50, 100, 150, 200, and 250 °C, respectively. For the reaction UO22+ + 2Cl- = UO2Cl2° the values of log β derived at these temperatures are 0.4, 0.58, 0.74, 1.44, 2.18, and 3.42. Values of the formation constant estimated for uranyl-chloride species predict the high concentrations of U observed by Richard et al. (2011) in fluid inclusions of the giant McArthur River unconformity-type uranium deposit.

  13. Solution of a partial differential equation subject to temperature overspecification by He's homotopy perturbation method

    International Nuclear Information System (INIS)

    Dehghan, Mehdi; Shakeri, Fatemeh

    2007-01-01

    In this work, the solution of an inverse problem concerning a diffusion equation with source control parameters is presented. The homotopy perturbation method is employed to solve this equation. This method changes a difficult problem into a simple problem which can be easily solved. In this procedure, according to the homotopy technique, a homotopy with an embedding parameter p element of [0,1] is constructed, and this parameter is considered a 'small parameter', so the method is called the homotopy perturbation method, which can take full advantage of the traditional perturbation method and homotopy technique. The approximations obtained by the proposed method are uniformly valid not only for small parameters, but also for very large parameters. The fact that this technique, in contrast to the traditional perturbation methods, does not require a small parameter in the system, leads to wide applications in nonlinear equations

  14. Electrolytic conductivity and molar heat capacity of two aqueous solutions of ionic liquids at room-temperature: Measurements and correlations

    International Nuclear Information System (INIS)

    Lin Peiyin; Soriano, Allan N.; Leron, Rhoda B.; Li Menghui

    2010-01-01

    As part of our systematic study on physicochemical characterization of ionic liquids, in this work, we report new measurements of electrolytic conductivity and molar heat capacity for aqueous solutions of two 1-ethyl-3-methylimidazolium-based ionic liquids, namely: 1-ethyl-3-methylimidazolium dicyanamide and 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate, at normal atmospheric condition and for temperatures up to 353.2 K. The electrolytic conductivity and molar heat capacity were measured by a commercial conductivity meter and a differential scanning calorimeter (DSC), respectively. The estimated experimental uncertainties for the electrolytic conductivity and molar heat capacity measurements were ±1% and ±2%, respectively. The property data are reported as functions of temperature and composition. A modified empirical equation from another researcher was used to correlate the temperature and composition dependence of the our electrolytic conductivity results. An excess molar heat capacity expression derived using a Redlich-Kister type equation was used to represent the temperature and composition dependence of the measured molar heat capacity and calculated excess molar heat capacity of the solvent systems considered. The correlations applied represent the our measurements satisfactorily as shown by an acceptable overall average deviation of 6.4% and 0.1%, respectively, for electrolytic conductivity and molar heat capacity.

  15. Sunlight Induced Rapid Oil Absorption and Passive Room-Temperature Release: An Effective Solution toward Heavy Oil Spill Cleanup

    KAUST Repository

    Wu, Mengchun

    2018-05-18

    Rapid cleanup and easy recovery of spilled heavy oils is always a great challenge due to their high viscosity (>103 mPa s). One of the efficient methods to absorb highly viscous oils is to reduce their viscosity by increasing their temperature. In this work, the authors integrate the sunlight‐induced light‐to‐heat conversion effect of polypyrrole (PPy) and thermoresponsive property of poly(N‐isopropylacrylamide) (PNIPAm) into the melamine sponge, which successfully delivers a fast heavy oil absorption under sunlight and passive oil release underwater at room temperature. Thanks to the rationally designed functionalities, the PNIPAm/PPy functionalized sponges possess oleophilicity and hydrophobicity under sunlight. Due to the photothermal effect of PPy, the sponges locally heat up contacting heavy oil under sunlight and reduce its viscosity to a point where the oil voluntarily flow into the pores of the sponge. The material in this work is able to rapidly absorb the heavy oil with room temperature viscosity as high as ≈1.60 × 105 mPa s. The absorbed oil can be passively forced out the sponge underwater at room temperature due to the hydrophilicity of PNIPAm. The sunlight responsive and multifunctional sponge represents a meaningful attempt in coming up with a sustainable solution toward heavy oil spill.

  16. Sunlight Induced Rapid Oil Absorption and Passive Room-Temperature Release: An Effective Solution toward Heavy Oil Spill Cleanup

    KAUST Repository

    Wu, Mengchun; Shi, Yusuf; Chang, Jian; Li, Renyuan; Ong, Chi Siang; Wang, Peng

    2018-01-01

    Rapid cleanup and easy recovery of spilled heavy oils is always a great challenge due to their high viscosity (>103 mPa s). One of the efficient methods to absorb highly viscous oils is to reduce their viscosity by increasing their temperature. In this work, the authors integrate the sunlight‐induced light‐to‐heat conversion effect of polypyrrole (PPy) and thermoresponsive property of poly(N‐isopropylacrylamide) (PNIPAm) into the melamine sponge, which successfully delivers a fast heavy oil absorption under sunlight and passive oil release underwater at room temperature. Thanks to the rationally designed functionalities, the PNIPAm/PPy functionalized sponges possess oleophilicity and hydrophobicity under sunlight. Due to the photothermal effect of PPy, the sponges locally heat up contacting heavy oil under sunlight and reduce its viscosity to a point where the oil voluntarily flow into the pores of the sponge. The material in this work is able to rapidly absorb the heavy oil with room temperature viscosity as high as ≈1.60 × 105 mPa s. The absorbed oil can be passively forced out the sponge underwater at room temperature due to the hydrophilicity of PNIPAm. The sunlight responsive and multifunctional sponge represents a meaningful attempt in coming up with a sustainable solution toward heavy oil spill.

  17. Sulfate influx on band 3 protein of equine erythrocyte membrane (Equus caballus) using different experimental temperatures and buffer solutions.

    Science.gov (United States)

    Casella, S; Piccione, D; Ielati, S; Bocchino, E G; Piccione, G

    2013-06-01

    The aim of this study was to assess the anion transport in equine erythrocytes through the measurement of the sulfate uptake operating from band 3 using different experimental temperatures and buffer solutions. Blood samples of six clinically healthy horses were collected via jugular vein puncture, and an emochrome-citometric examination was performed. The blood was divided into four aliquots and by centrifugation and aspiration the plasma and buffy coat were carefully discarded. The red blood cells were washed with an isosmotic medium and centrifuged. The obtained cell suspensions were incubated with two different experimental buffer solutions (buffer A: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM glucose; and buffer B: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM MgCl2) in a water bath for 1 h at 25 °C and 37 °C. Normal erythrocytes, suspended at 3% hematocrit, were used to measure the SO4= influx by absorption spectrophotometry at 425 nm wavelength. Unpaired Student's t-test showed a statistically significant decrease (P buffer solutions. Comparing the buffer A with buffer B unpaired Student's t-test showed statistically lower values (P < 0.0001) for A solution versus B solution both at 25 °C and at 37 °C. The greater inhibition of SO4 (=) influx measured in equine erythrocytes indicates the increased formation of the sulfydryl bonds in band 3 and the modulation of the sulfydryl groups, culminating in the conformational changes in band 3. Copyright © 2012 John Wiley & Sons, Ltd.

  18. Creative design-by-analysis solutions applied to high-temperature components

    International Nuclear Information System (INIS)

    Dhalla, A.K.

    1993-01-01

    Elevated temperature design has evolved over the last two decades from design-by-formula philosophy of the ASME Boiler and Pressure Vessel Code, Sections I and VIII (Division 1), to the design-by-analysis philosophy of Section III, Code Case N-47. The benefits of design-by-analysis procedures, which were developed under a US-DOE-sponsored high-temperature structural design (HTSD) program, are illustrated in the paper through five design examples taken from two U.S. liquid metal reactor (LMR) plants. Emphasis in the paper is placed upon the use of a detailed, nonlinear finite element analysis method to understand the structural response and to suggest design optimization so as to comply with Code Case N-47 criteria. A detailed analysis is cost-effective, if selectively used, to qualify an LMR component for service when long-lead-time structural forgings, procured based upon simplified preliminary analysis, do not meet the design criteria, or the operational loads are increased after the components have been fabricated. In the future, the overall costs of a detailed analysis will be reduced even further with the availability of finite element software used on workstations or PCs

  19. A preliminary study of the influence of ions in the pore solution of hardened cement pastes on the porosity determination by low temperature calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Min, E-mail: miwu@byg.dtu.dk [Department of Civil Engineering, Technical University of Denmark, Building 118, 2800 Lyngby (Denmark); Johannesson, Björn [Department of Civil Engineering, Technical University of Denmark, Building 118, 2800 Lyngby (Denmark); Geiker, Mette [Department of Structural Engineering, Norwegian University of Science and Technology, Trondheim (Norway)

    2014-08-10

    Highlights: • Ionic concentrations in cement pore solution at freezing temperatures were simulated. • Effects of ions in determining pore sizes by low temperature calorimetry were studied. • Ions in cement pore solution affect the pore size determination to a limited extent. - Abstract: Thermodynamic modeling was used to predict the ionic concentrations in the pore solution of cement pastes at different temperatures during a freezing and melting measurement in low temperature calorimetry (LTC) studies. By using the predicted ionic concentrations, the temperature depressions caused by the ions presented in the pore solution were determined. The influence of the freezing/melting point depression caused by the ions on the determined pore size distribution by LTC was demonstrated. Thermodynamic modeling using the program PHREEQC was performed on the cylinder and powder samples of cement pastes prepared by two types of cements, i.e., CEM I 32.5 R and CEM III/B 42.5 N. Using the modeled ionic concentrations, the calculated differential pore size distributions for the studied samples with and without considering the temperature depression caused by the ions in the pore solution were compared. The results indicate that for the studied cement paste samples, the influence of the temperature depression caused by the presence of the ions in the pore solution on the determination of the pore size distribution by LTC is limited.

  20. A preliminary study of the influence of ions in the pore solution of hardened cement pastes on the porosity determination by low temperature calorimetry

    International Nuclear Information System (INIS)

    Wu, Min; Johannesson, Björn; Geiker, Mette

    2014-01-01

    Highlights: • Ionic concentrations in cement pore solution at freezing temperatures were simulated. • Effects of ions in determining pore sizes by low temperature calorimetry were studied. • Ions in cement pore solution affect the pore size determination to a limited extent. - Abstract: Thermodynamic modeling was used to predict the ionic concentrations in the pore solution of cement pastes at different temperatures during a freezing and melting measurement in low temperature calorimetry (LTC) studies. By using the predicted ionic concentrations, the temperature depressions caused by the ions presented in the pore solution were determined. The influence of the freezing/melting point depression caused by the ions on the determined pore size distribution by LTC was demonstrated. Thermodynamic modeling using the program PHREEQC was performed on the cylinder and powder samples of cement pastes prepared by two types of cements, i.e., CEM I 32.5 R and CEM III/B 42.5 N. Using the modeled ionic concentrations, the calculated differential pore size distributions for the studied samples with and without considering the temperature depression caused by the ions in the pore solution were compared. The results indicate that for the studied cement paste samples, the influence of the temperature depression caused by the presence of the ions in the pore solution on the determination of the pore size distribution by LTC is limited

  1. Accurate solid solution range of BiMnxFe3-xO6 and low temperature magnetism

    Science.gov (United States)

    Jiang, Pengfei; Yue, Mufei; Cong, Rihong; Gao, Wenliang; Yang, Tao

    2017-11-01

    BiMnxFe3-xO6 (x = 1) represents a new type of oxide structure containing Bi3+ and competing magnetic super-exchanges. In literature, multiple magnetic states were realized at low temperatures in BiMnFe2O6, and the hypothetical parent compounds (BiMn3O6, BiFe3O6) were predicted to be different in magnetism. Herein, we performed a careful study on the syntheses of BiMnxFe3-xO6 at ambient pressure, and the solid solution range was determined to be 0.9 ≤ x ≤ 1.3 by Rietveld refinements on high-quality powder X-ray diffraction data. Due to the very similar cationic size of Mn3+ and Fe3+, and possibly the structural rigidity, there was no significant structure change in the whole range of solid solution. The magnetic behavior of BiMnxFe3-xO6 (x = 1.2, 1.22, 1.26, 1.28 and 1.3) was generally similar to BiMnFe2O6, while the relative higher concentration of Mn3+ led to the decreasing of the antiferromagnetic ordering temperature.

  2. Effect of annealing temperature on physical properties of solution processed nickel oxide thin films

    Science.gov (United States)

    Sahoo, Pooja; Thangavel, R.

    2018-05-01

    In this report, NiO thin films were prepared at different annealing temperatures from nickel acetate precursor by sol-gel spin coating method. These films were characterized by different analytical techniques to obtain their structural, optical morphological and electrical properties using X-ray diffractometer (XRD), Field emission scanning electron microscopy (FESEM), UV-Vis NIR double beam spectrophotometer and Keithley 2450 source meter respectively. FESEM images clearly indicates the formation of a homogenous and porous films. Due to their porosity, they can be used in sensing applications. The optical absorption spectra elucidated that the films are highly transparent and have a suitable band gap which are in similar agreement with earlier reports. The current enhancement under illumination shows the suitability of nanostructured NiO thin films in its application in photovoltaics.

  3. Numerical solutions to the critical state in a magnet-high temperature superconductor interaction

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Alonso, D; Coombs, T A; Campbell, A M [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

    2005-02-01

    This paper presents an algorithm to simulate the electromagnetic behaviour of devices containing high temperature superconductors in axially symmetric problems. The numerical method is built within the finite element method. The electromagnetic properties of HTSCs are described through the critical-state model. Measurements of the axial force between a permanent magnet and a melt-textured YBCO puck are obtained in order to validate the method. This simple system is modelled so that the proposed method obtains the current distribution and electromagnetic fields in the HTSC. The forces in the interaction between the magnet and the HTSC puck can then be calculated. A comparison between experimental and simulation results shows good matching. The simplification of using the critical-state model and ignoring flux creep in this type of configuration is also explored.

  4. Resonance scattering and low-temperature electron mobility in HgTe-based gapless solid solutions

    International Nuclear Information System (INIS)

    Raikh, M.Eh.; Ehfros, A.L.

    1986-01-01

    Low-temperature electron mobility in a gapless semiconductor conditioned by electron resonance scattering on neutral acceptors, the levels of which are located in narrow vicinity near the Fermi level, is calculated. Mobility turns to be inverse proportional to density of acceptor states at the Fermi level. If donor concentration is rather high, then presence of a Coulomb gap at the Fermi level in the density of acceptor states conditioned by long-range character of Coulomb interaction should be taken into account for calculation of mobility. The Fermi level is placed in the tail of the acceptor state density at rather low donor concentration, and the Coulomb gap is absent at the Fermi level. A case of high acceptor concentration, when the acceptor states are delocalized at the Fermi level, is also considered

  5. Degradation behavior of PVC film in aqueous solution at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Shun-Myung; Kim, Jong-Hwa; Lee, Soo [Changwon National University, Changwon(Korea)

    2001-02-28

    The heat treatment of PVC film containing PVC 65%, DOP (Dioctyl Phthalate) 32% as plasticizer, Ca-Zn stearates and surface agent was performed under several conditions to study the dehydrochlorination of PVC and char production. In the case of H{sub 2}SO{sub 4}, the dehydrochlorination was ca.100% at 250 deg.C for 3h. The char involving the smaller pores was produced with hydrothermal treatment. The pore size became small with increasing the treatment time and temperature. In the case of treatment with Ca(OH){sub 2}, the sizes of pores produced in char were about sever {approx}10 {mu}m at 225 deg.C for 12h. In the case of H{sub 2}SO{sub 4}, the size of pores were about 1 {mu}m in 5M H{sub 2}SO{sub 4} for 12h. (author). 6 refs., 3 tabs., 11 figs.

  6. High-temperature thermodynamic data for species in aqueous solution. Final report

    International Nuclear Information System (INIS)

    Cobble, J.W.; Murray, R.C. Jr.; Turner, P.J.; Chen, K.

    1982-05-01

    This final report summarizes the results of experimental and theoretical research on the high temperature thermodynamic properties of aqueous species important to nuclear reactor water chemistry. Methods of predicting thermodynamic functions are included for electrolytes up to 300 0 C where experimental data are lacking. Data in the literature are evaluated and tables of important equilibrium constants for 78 reactions encountered in corrosion and precipitation in nuclear reactors are listed up to 300 0 C. Finally, tables of free energy functions from 0 to 300 0 C are given for 56 individual species. These data represented form a major compilation resulting from the most advanced experimental and theoretical methods. Illustrations of the use of the tables are given for problems involving pH control, precipitation, and corrosion. 11 figures, 100 tables

  7. Hydrogen bond network relaxation in aqueous polyelectrolyte solutions: the effect of temperature

    International Nuclear Information System (INIS)

    Sarti, S; Bordi, F; Truzzolillo, D

    2012-01-01

    Dielectric spectroscopy data over the range 100 MHz-40 GHz allow for a reliable analysis of two of the major relaxation phenomena for polyelectrolytes (PE) in water. Within this range, the dielectric relaxation of pure water is dominated by a near-Debye process at ν = 18.5 GHz corresponding to a relaxation time of τ = 8.4 ps at 25 °C. This mode is commonly attributed to the cooperative relaxation specific to liquids forming a hydrogen bond network (HBN) and arising from long range H-bond-mediated dipole-dipole interactions. The presence of charged polymers in water partially modifies the dielectric characteristics of the orientational water molecule relaxation due to a change of the dielectric constant of water surrounding the charges on the polyion chain. We report experimental results on the effect of the presence of a standard flexible polyelectrolyte (sodium polyacrylate) on the HBN relaxation in water for different temperatures, showing that the HBN relaxation time does not change by increasing the polyelectrolyte density in water, even if relatively high concentrations are reached (0.02 monomol l -1 ≤ C ≤ 0.4 monomol l -1 ). We also find that the effect of PE addition on the HBN relaxation is not even a broadening of its distribution, rather a decrease of the spectral weight that goes beyond the pure volume fraction effect. This extra decrease is larger at low T and less evident at high T, supporting the idea that the correlation length of the water is less affected by the presence of charged flexible chains at high temperatures. (paper)

  8. Inverted Organic Solar Cells with Low-Temperature Al-Doped-ZnO Electron Transport Layer Processed from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Qianni Zhang

    2018-01-01

    Full Text Available The aqueous-based Zn-ammine complex solutions represent one of the most promising routes to obtain the ZnO electron transport layer (ETL at a low temperature in inverted organic solar cells (OSCs. However, to dope the ZnO film processed from the Zn-ammine complex solutions is difficult since the introduction of metal ions into the Zn-ammine complex is a nontrivial process as ammonium hydroxide tends to precipitate metal salts due to acid-base neutralization reactions. In this paper, we investigate the inverted OSCs with Al-doped-ZnO ETL made by immersion of metallic Al into the Zn-ammine precursor solution. The effects of ZnO layer with different immersion time of Al on film properties and solar cell performance have been studied. The results show that, with the Al-doped-ZnO ETL, an improvement of the device performance could be obtained compared with the device with the un-doped ZnO ETL. The improved device performance is attributed to the enhancement of charge carrier mobility leading to a decreased charge carrier recombination and improved charge collection efficiency. The fabricated thin film transistors with the same ZnO or AZO films confirm the improved electrical characteristics of the Al doped ZnO film.

  9. Increasing parameter certainty and data utility through multi-objective calibration of a spatially distributed temperature and solute model

    Directory of Open Access Journals (Sweden)

    C. Bandaragoda

    2011-05-01

    Full Text Available To support the goal of distributed hydrologic and instream model predictions based on physical processes, we explore multi-dimensional parameterization determined by a broad set of observations. We present a systematic approach to using various data types at spatially distributed locations to decrease parameter bounds sampled within calibration algorithms that ultimately provide information regarding the extent of individual processes represented within the model structure. Through the use of a simulation matrix, parameter sets are first locally optimized by fitting the respective data at one or two locations and then the best results are selected to resolve which parameter sets perform best at all locations, or globally. This approach is illustrated using the Two-Zone Temperature and Solute (TZTS model for a case study in the Virgin River, Utah, USA, where temperature and solute tracer data were collected at multiple locations and zones within the river that represent the fate and transport of both heat and solute through the study reach. The result was a narrowed parameter space and increased parameter certainty which, based on our results, would not have been as successful if only single objective algorithms were used. We also found that the global optimum is best defined by multiple spatially distributed local optima, which supports the hypothesis that there is a discrete and narrowly bounded parameter range that represents the processes controlling the dominant hydrologic responses. Further, we illustrate that the optimization process itself can be used to determine which observed responses and locations are most useful for estimating the parameters that result in a global fit to guide future data collection efforts.

  10. Effect of Challenge Temperature and Solute Type on Heat Tolerance of Salmonella Serovars at Low Water Activity

    Science.gov (United States)

    Mattick, K. L.; Jørgensen, F.; Wang, P.; Pound, J.; Vandeven, M. H.; Ward, L. R.; Legan, J. D.; Lappin-Scott, H. M.; Humphrey, T. J.

    2001-01-01

    Salmonella spp. are reported to have an increased heat tolerance at low water activity (aw; measured by relative vapor pressure [rvp]), achieved either by drying or by incorporating solutes. Much of the published data, however, cover only a narrow treatment range and have been analyzed by assuming first-order death kinetics. In this study, the death of Salmonella enterica serovar Typhimurium DT104 when exposed to 54 combinations of temperature (55 to 80°C) and aw (rvp 0.65 to 0.90, reduced using glucose-fructose) was investigated. The Weibull model (LogS = −btn) was used to describe microbial inactivation, and surface response models were developed to predict death rates for serovar Typhimurium at all points within the design surface. The models were evaluated with data generated by using six different Salmonella strains in place of serovar Typhimurium DT104 strain 30, two different solutes in place of glucose-fructose to reduce aw, or six low-aw foods artificially contaminated with Salmonella in place of the sugar broths. The data demonstrate that, at temperatures of ≥70°C, Salmonella cells at low aw were more heat tolerant than those at a higher aw but below 65°C the reverse was true. The same patterns were generated when sucrose (rvp 0.80 compared with 0.90) or NaCl (0.75 compared with 0.90) was used to reduce aw, but the extent of the protection afforded varied with solute type. The predictions of thermal death rates in the low-aw foods were usually fail-safe, but the few exceptions highlight the importance of validating models with specific foods that may have additional factors affecting survival. PMID:11526015

  11. Investigation of optimal manufacturing process for freeze-dried formulations: Observation of frozen solutions by low temperature X-ray diffraction measurements

    International Nuclear Information System (INIS)

    Egawa, Hiroaki; Yonemochi, Etsuo; Terada, Katsuhide

    2005-01-01

    Freeze-drying is used for the production of sterile injections in the pharmaceutical industry. However, most pharmaceutical compounds are obtained as less stable amorphous form. Freeze crystallization by annealing is an effective method for pharmaceutical compounds that fail to crystallize in the freeze-drying process. Crystallization occurs in the frozen solution during the thermal treatment. In order to establish suitable annealing conditions efficiently, it is important to observe the crystallization process directly in the frozen solution. Recently, low temperature X-ray diffraction has been used to observe frozen solutions. In order to investigate the crystallization process kinetically, the temperature of the low temperature X-ray diffraction instrument must be accurately controlled. We calibrated the temperature of X-ray diffraction instrument by measuring eutectic temperatures of solutions for a series of compounds. Each eutectic crystal was observed in frozen solution with ice crystal below the eutectic temperature. Eutectic temperatures were detected by the decrease in diffraction intensity associated with heating from below the eutectic temperature. Good correlation was obtained between values in the literature and experimental values

  12. Highly efficient organic solar Cells based on a robust room-temperature solution-processed copper iodide hole transporter

    KAUST Repository

    Zhao, Kui

    2015-07-30

    Achieving high performance and reliable organic solar cells hinges on the development of stable and energetically suitable hole transporting buffer layers in tune with the electrode and photoactive materials of the solar cell stack. Here we have identified solution-processed copper(I) iodide (CuI) thin films with low-temperature processing conditions as an effective hole–transporting layer (HTL) for a wide range of polymer:fullerene bulk heterojunction (BHJ) systems. The solar cells using CuI HTL show higher power conversion efficiency (PCE) in standard device structure for polymer blends, up to PCE of 8.8%, as compared with poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL, for a broad range of polymer:fullerene systems. The CuI layer properties and solar cell device behavior are shown to be remarkably robust and insensitive to a wide range of processing conditions of the HTL, including processing solvent, annealing temperature (room temperature up to 200 °C), and film thickness. CuI is also shown to improve the overall lifetime of solar cells in the standard architecture as compared to PEDOT:PSS. We further demonstrate promising solar cell performance when using CuI as top HTL in an inverted device architecture. The observation of uncommon properties, such as photoconductivity of CuI and templating effects on the BHJ layer formation, are also discussed. This study points to CuI as being a good candidate to replace PEDOT:PSS in solution-processed solar cells thanks to the facile implementation and demonstrated robustness of CuI thin films.

  13. Highly efficient organic solar Cells based on a robust room-temperature solution-processed copper iodide hole transporter

    KAUST Repository

    Zhao, Kui; Ngongang Ndjawa, Guy Olivier; Jagadamma, Lethy Krishnan; El Labban, Abdulrahman; Hu, Hanlin; Wang, Qingxiao; Li, Ruipeng; Abdelsamie, Maged; Beaujuge, Pierre; Amassian, Aram

    2015-01-01

    Achieving high performance and reliable organic solar cells hinges on the development of stable and energetically suitable hole transporting buffer layers in tune with the electrode and photoactive materials of the solar cell stack. Here we have identified solution-processed copper(I) iodide (CuI) thin films with low-temperature processing conditions as an effective hole–transporting layer (HTL) for a wide range of polymer:fullerene bulk heterojunction (BHJ) systems. The solar cells using CuI HTL show higher power conversion efficiency (PCE) in standard device structure for polymer blends, up to PCE of 8.8%, as compared with poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL, for a broad range of polymer:fullerene systems. The CuI layer properties and solar cell device behavior are shown to be remarkably robust and insensitive to a wide range of processing conditions of the HTL, including processing solvent, annealing temperature (room temperature up to 200 °C), and film thickness. CuI is also shown to improve the overall lifetime of solar cells in the standard architecture as compared to PEDOT:PSS. We further demonstrate promising solar cell performance when using CuI as top HTL in an inverted device architecture. The observation of uncommon properties, such as photoconductivity of CuI and templating effects on the BHJ layer formation, are also discussed. This study points to CuI as being a good candidate to replace PEDOT:PSS in solution-processed solar cells thanks to the facile implementation and demonstrated robustness of CuI thin films.

  14. The existence of a temperature-driven solid solution in LixFePO4 for 0 <= x <= 1

    Science.gov (United States)

    Delacourt, Charles; Poizot, Philippe; Tarascon, Jean-Marie; Masquelier, Christian

    2005-03-01

    Lithium-ion batteries have revolutionized the powering of portable electronics. Electrode reactions in these electrochemical systems are based on reversible insertion/deinsertion of Li+ ions into the host electrode material with a concomitant addition/removal of electrons into the host. If such batteries are to find a wider market such as the automotive industry, less expensive positive electrode materials will be required, among which LiFePO4 is a leading contender. An intriguing fundamental problem is to understand the fast electrochemical response from the poorly electronic conducting two-phase LiFePO4/FePO4 system. In contrast to the well-documented two-phase nature of this system at room temperature, we give the first experimental evidence of a solid solution LixFePO4 (0 <= x <= 1) at 450 °C, and two new metastable phases at room temperature with Li0.75FePO4 and Li0.5FePO4 composition. These experimental findings challenge theorists to improve predictive models commonly used in the field. Our results may also lead to improved performances of these electrodes at elevated temperatures.

  15. Effect of temperature on the extraction of europium (III) bymixtures of neutral phosphoro-organic extractants from nitrate solutions

    International Nuclear Information System (INIS)

    Milchlin, E.B.; Khmuran, M.A.; Mikhailichenko, A.I.

    1986-01-01

    A study has been made of the distribution of microquantities of europium (III) on extraction with neutral phosphoorganic compounds-tri-n-butyl phosphate (TBP), diisooctylmethyl phosphonate (DIOMP),trialkylphosphine oxide with dissimilar radicals (PODR), or mixtures thereof-from a solution of 2 mole/liter NH 4 NO 3 and 0.01 mole/liter HNO 3 , in the temperature range 20-60 0 C. A temperature rise results in a decrease of the distribution coefficients of the europium on extraction by all of the extractants tested and their mixtures, and also in a reduction of the synergistic effect in extraction by mixtures of the extractants. Based on an investigation of the temperature dependences of the distribution constants of europium nitrate upon extraction by TBP, DIOMP, PODR, or their mixtures, values have been determined for the enthalpy, free energy, and entropy of extraction. It is shown that the enthalpy (-ΔH) increases in the order TBP< DIOMP< PODR. In an extraction with mixed extractants, the enthalpy has a value intermediate between those with the individual extractants. The entropy of extraction (-ΔS) increases in the reverse order PODR< DIOMP< TBP

  16. Effect of co-solute and gelation temperature on milk protein and gum tragacanth interaction in acidified gels.

    Science.gov (United States)

    Hatami, Masoud; Nejatian, Mohammad; Mohammadifar, Mohammad Amin

    2012-05-01

    The aim of this study was to investigate the role of process conditions and system composition on the acid-induced gelation of a mixture of milk protein and gum tragacanth. This was studied by determining the effects of co-solute (lactose) addition (3, 5 and 7%) and gelation temperature (25, 37 and 45°C) on the mixture's rheological properties and microstructure using a combination of techniques including small-deformation rheology and scanning electron microscopy. The presence of lactose played an important role in the microstructure formation of gels but did not change most rheological properties. The microstructure of gels formed in the presence of lactose was coarser and more particulate, but less interconnected; this can be explained by lactose's role in improving protein aggregation. Gels prepared at a lower temperature had a high structure strength, as indicated by their high storage modulus, τ(f) and G(f) values. Low gelation temperature also caused a more branched and homogenous microstructure. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Lignocellulosic Composites Prepared Utilizing Aqueous Alkaline/Urea Solutions with Cold Temperatures

    Directory of Open Access Journals (Sweden)

    Brent Tisserat

    2018-01-01

    Full Text Available Lignocellulosic composites (LCs were fabricated by partially dissolving cotton to create a matrix that was reinforced with osage orange wood (OOW particles and/or blue agave fibers (AF. LCs were composed of 15–35% cotton matrix and 65–85% OWW/AF reinforcement. The matrix was produced by soaking cotton wool in a cold aqueous alkaline/urea solvent and was stirred for 15 minutes at 350 rpm to create a viscous gel. The gel was then reinforced with lignocellulosic components, mixed, and then pressed into a panel mold. LC panels were soaked in water to remove the aqueous solvent and then oven dried to obtain the final LC product. Several factors involved in the preparation of these LCs were examined including reaction temperatures (−5 to −15°C, matrix concentration (15–35% cotton, aqueous solvent volume (45–105 ml/panel, and the effectiveness of employing various aqueous solvent formulations. The mechanical properties of LCs were determined and reported. Conversion of the cotton into a suitable viscous gel was critical in order to obtain LCs that exhibited high mechanical properties. LCs with the highest mechanical properties were obtained when the cotton wools were subjected to a 4.6% LiOH/15% urea solvent at −12.5°C using an aqueous solvent volume of 60 ml/panel. Cotton wool subjected to excessive cold alkaline solvents volumes resulted in irreversible cellulose breakdown and a resultant LC that exhibited poor mechanical properties.

  18. The role of the temperature in the morphology and properties of zinc oxide structures obtained by electrosynthesis in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Jaffry, U.; Mazario, E. [Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Física Aplicada, 28049 Madrid (Spain); Lemus, J. [CICECO – Aveiro Institute of Materials, Chemistry Department, University of Aveiro, 3810-193 Aveiro (Portugal); Rivero, M.; Muñoz-Bonilla, A. [Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Física Aplicada, 28049 Madrid (Spain); Herrasti, P., E-mail: pilar.herrasti@uam.es [Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Física Aplicada, 28049 Madrid (Spain)

    2016-09-15

    Herein, ZnO micro and nanostructures were synthesized by an electrochemical method in aqueous solution employing NaCl as the electrolyte. Different parameters influencing the synthesis process, i.e. current intensity, reaction time and temperature, were investigated. From this, it was concluded that the productivity of the reaction increases with longer reaction time, whereas the use of higher current intensity augments the specific energy consumption. On the other hand, the increase in temperature seems to exert a negative effect. The characterization of the resulting materials by scanning electron microscopy, X-ray diffraction and thermogravimetric analysis demonstrated that a mixture of Zn(OH){sub 2} and ZnO crystalline structures is formed directly from the synthesis procedure. The content of Zn(OH){sub 2} phase in the sample decreases as the temperature of the synthesis increases, this fact indicates that the low productivity obtained at higher temperatures is related to the nature of the resulting material. Thermal annealing of the samples containing both phases prepared following synthesis allows the phase transformation from Zn(OH){sub 2} to pure ZnO structures. The band gap energies of the ZnO materials were determined by diffuse reflectance measurements according to the Kubelka Munk theory, revealing low values in all the cases which were highly dependent on the size of crystals within the materials. The photocatalytic properties of the pure ZnO samples post calcination were investigated by the decomposition of an organic dye under UV light irradiation. The results show the beneficial photocatalytic properties of the samples that had undergone calcination, these were superior in comparison to those prepared at room temperature which mainly consisted of Zn(OH){sub 2}. - Highlights: • ZnO micro and nanostructures were synthesized by an electrochemical method. • Increasing the applied current and synthesis temperature augments the specific energy

  19. Synthesis and evaluation of temperature- and glucose-sensitive nanoparticles based on phenylboronic acid and N-vinylcaprolactam for insulin delivery

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jun-zi [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai, 201620 (China); Bremner, David H. [School of Science, Engineering and Technology, Kydd Building, Abertay University, Dundee DD1 1HG, Scotland (United Kingdom); Li, He-yu; Sun, Xiao-zhu [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai, 201620 (China); Zhu, Li-Min, E-mail: lzhu@dhu.edu.cn [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai, 201620 (China)

    2016-12-01

    Poly N-vinylcaprolactam-co-acrylamidophenylboronic acid p(NVCL-co-AAPBA) was prepared from N-vinylcaprolactam (NVCL) and 3-acrylamidophenylboronic acid (AAPBA), using 2,2-azobisisobutyronitrile (AIBN) as initiator. The synthesis and structure of the polymer were examined by Fourier Transform infrared spectroscopy (FT-IR) and {sup 1}H-NMR. Dynamic light scattering (DLS), lower critical solution temperature (LCST) and transmission electron microscopy (TEM) were utilized to characterize the nanoparticles, CD spectroscopy was used to determine if there were any changes to the conformation of the insulin, and cell and animal toxicity were also investigated. The prepared nanoparticles were found to be monodisperse submicron particles and were glucose- and temperature-sensitive. In addition, the nanoparticles have good insulin-loading characteristics, do not affect the conformation of the insulin and show low-toxicity to cells and animals. These p(NVCL-co-AAPBA) nanoparticles may have some value for insulin or other hypoglycemic protein delivery. - Highlights: • A comprehensive study of a nanoparticles may have some value for insulin or other hypoglycemic protein delivery. • p(NVCL-co-AAPBA)'s synthetic method is simple, convenient to carry out. • NVCL is low toxic and safe. • The evaluation of acute toxicity and chronic toxicity is the most highlight.

  20. Controllable synthesis of spindle-like ZnO nanostructures by a simple low-temperature aqueous solution route

    International Nuclear Information System (INIS)

    Lu Hongxia; Zhao Yunlong; Yu Xiujun; Chen Deliang; Zhang Liwei; Xu Hongliang; Yang Daoyuan; Wang Hailong; Zhang Rui

    2011-01-01

    Spindle-like ZnO nanostructures were successfully synthesized through direct precipitation of zinc acetate aqueous solution at 60 deg. C. Phase structure, morphology and microstructure of the products were investigated by X-ray diffraction, TG-DTA, FTIR and field emission scanning electron microscopy (FESEM). Result showed that hexagonal wurtzite structure ZnO nanostructures with about 100 nm in diameter and 100-200 nm in length were obtained. HMTA acted as a soft template in the process and played an important role in the formation of spindle-like ZnO nanostructures. Meanwhile, different morphologies were also obtained by altering synthetic temperature, additional agents and the ratios of Zn 2+ /OH - . Possible mechanism for the variations of morphology with synthesis parameters was also discussed in this paper.

  1. SOLUBILITIES AND PHYSICAL PROPERTIES OF SATURATED SOLUTIONS IN THE COPPER SULFATE + SULFURIC ACID + SEAWATER SYSTEM AT DIFFERENT TEMPERATURES

    Directory of Open Access Journals (Sweden)

    F. J. Justel

    2015-09-01

    Full Text Available AbstractIn Chile, the most important economic activity is mining, concentrated in the north of the country. This is a desert region with limited water resources; therefore, the mining sector requires research and identification of alternative sources of water. One alternative is seawater, which can be a substitute of the limited fresh water resources in the region. This work determines the influence of seawater on the solid-liquid equilibrium for acid solutions of copper sulfate at different temperatures (293.15 to 318.15 K, and its effect on physical properties (density, viscosity, and solubility. Knowledge of these properties and solubility data are useful in the leaching process and in the design of copper sulfate pentahydrate crystallization plants from the leaching process using seawater by means of the addition of sulfuric acid.

  2. Room-Temperature H2 Gas Sensing Characterization of Graphene-Doped Porous Silicon via a Facile Solution Dropping Method

    Directory of Open Access Journals (Sweden)

    Nu Si A. Eom

    2017-11-01

    Full Text Available In this study, a graphene-doped porous silicon (G-doped/p-Si substrate for low ppm H2 gas detection by an inexpensive synthesis route was proposed as a potential noble graphene-based gas sensor material, and to understand the sensing mechanism. The G-doped/p-Si gas sensor was synthesized by a simple capillary force-assisted solution dropping method on p-Si substrates, whose porosity was generated through an electrochemical etching process. G-doped/p-Si was fabricated with various graphene concentrations and exploited as a H2 sensor that was operated at room temperature. The sensing mechanism of the sensor with/without graphene decoration on p-Si was proposed to elucidate the synergetic gas sensing effect that is generated from the interface between the graphene and p-type silicon.

  3. Analysis of the corrosion of carbon steels in simulated salt repository brines and acid chloride solutions at high temperatures

    International Nuclear Information System (INIS)

    Diercks, D.R.; Kassner, T.F.

    1988-04-01

    An analysis of literature data on the corrosion of carbon steels in anoxic brines and acid chloride solutions was performed, and the results were used to assess the expected life of high-level nuclear waste package containers in a salt repository environment. The corrosion rate of carbon steels in moderately acidic aqueous chloride environments obeys an Arrhenius dependence on temperature and a (pH 2 ) -1/2 dependence on hydrogen partial pressure. The cathodic reduction of water to produce hydrogen is the rate-controlling step in the corrosion process. An expression for the corrosion rate incorporating these two dependencies was used to estimate the corrosion life of several proposed waste package configurations. 42 refs., 11 figs., 2 tabs

  4. Calorimetric study at different temperatures of iodine adsorption from organic solutions on outgassed 'eta' alumina and bayerite

    International Nuclear Information System (INIS)

    Della Gatta, G.; Stradella, L.; Venturello, G.

    1977-01-01

    The adsorption of iodine from solution in n-pentane at 27 0 C and in cyclohexane at 35 0 C and 50 0 C on eta-Al 2 O 3 and bayerite outgassed at R.T. has been studied with a calorimetric technique. The measurements were performed by means of a Calvet type calorimeter using a new cell conceived for the adsorption from solution. The integral molar energies of adsorption show, at low coverages, a very strong interaction of iodine with surface hydroxyl groups, possibly leading to charge-transfer complexes and reactions. A peculiar exothermic effect has been also evidenced before the monolayer completion, in correspondence with a 'step' on the adsorption isotherms. This result is interpreted in terms of cooperative adsorption implying the possible formation of surface clusters around the strongly absorbed molecules. On non-porous samples (bayerite) the adsorption temperature rise decrease the total amounts adsorbed. But on porous ones (eta-Al 2 O 3 ) the adsorption is increased. (orig./HK) [de

  5. Poisson-Fermi modeling of ion activities in aqueous single and mixed electrolyte solutions at variable temperature

    Science.gov (United States)

    Liu, Jinn-Liang; Eisenberg, Bob

    2018-02-01

    The combinatorial explosion of empirical parameters in tens of thousands presents a tremendous challenge for extended Debye-Hückel models to calculate activity coefficients of aqueous mixtures of the most important salts in chemistry. The explosion of parameters originates from the phenomenological extension of the Debye-Hückel theory that does not take steric and correlation effects of ions and water into account. By contrast, the Poisson-Fermi theory developed in recent years treats ions and water molecules as nonuniform hard spheres of any size with interstitial voids and includes ion-water and ion-ion correlations. We present a Poisson-Fermi model and numerical methods for calculating the individual or mean activity coefficient of electrolyte solutions with any arbitrary number of ionic species in a large range of salt concentrations and temperatures. For each activity-concentration curve, we show that the Poisson-Fermi model requires only three unchanging parameters at most to well fit the corresponding experimental data. The three parameters are associated with the Born radius of the solvation energy of an ion in electrolyte solution that changes with salt concentrations in a highly nonlinear manner.

  6. A preliminary study of the influence of ions in the pore solution of hardened cement pastes on the porosity determination by low temperature calorimetry

    DEFF Research Database (Denmark)

    Wu, Min; Johannesson, Björn; Geiker, Mette

    2014-01-01

    Thermodynamic modeling was used to predict the ionic concentrations in the pore solution of cement pastes at different temperatures during a freezing and melting measurement in low temperature calorimetry (LTC) studies. By using the predicted ionic concentrations, the temperature depressions caused...... compared. The results indicate that for the studied cement paste samples, the influence of the temperature depression caused by the presence of the ions in the pore solution on the determination of the pore size distribution by LTC is limited. (C) 2014 Elsevier B.V. All rights reserved....... by the ions presented in the pore solution were determined. The influence of the freezing/melting point depression caused by the ions on the determined pore size distribution by LTC was demonstrated. Thermodynamic modeling using the program PHREEQC was performed on the cylinder and powder samples of cement...

  7. Electrochemical evaluation of zinc effect on the corrosion of nickel alloy in PWR solutions with increasing temperature

    International Nuclear Information System (INIS)

    Alvial M, Gaston; Neves, Celia F.C.; Schvartzman, Monica M.A.M.; Quinan, Marco Antonio D.

    2007-01-01

    The main objective for the addition of zinc acetate to the reactor coolant system of PWRs is to effect radiation dose rate reductions. However, zinc is also added as an approach to mitigate the occurrence or severity of primary water stress corrosion cracking of nickel alloy 600. The mechanism by which zinc affects the corrosion of austenitic nickel-base alloys is by incorporation of zinc into the spinel oxide corrosion films. The purpose of this work is to evaluate the influence of zinc on the corrosion behavior of the nickel alloy 600 in PWR chemical environment (1200 ppm B, 2.2 ppm Li, deoxygenated water) with increasing temperature at room pressure. Electrochemical tests (anodic potentiodynamic polarization and electrochemical impedance spectroscopy) were used to characterize the alloy 600. Two conditions were applied: 0 and 100 ppb zinc and the temperature range was 50 - 90 deg C, at ambient pressure. Potentiodynamic polarization was inefficient to present conclusive results. Impedance measurements showed single semicircle in the Nyquist plane suggesting reduction of the charge transference resistance in zinc-containing solutions. This effect is evident at 90 deg C suggesting prejudicial influence of zinc for the alloy 600 at room pressure. (author)

  8. Effects of meteorological models on the solution of the surface energy balance and soil temperature variations in bare soils

    Science.gov (United States)

    Saito, Hirotaka; Šimůnek, Jiri

    2009-07-01

    SummaryA complete evaluation of the soil thermal regime can be obtained by evaluating the movement of liquid water, water vapor, and thermal energy in the subsurface. Such an evaluation requires the simultaneous solution of the system of equations for the surface water and energy balance, and subsurface heat transport and water flow. When only daily climatic data is available, one needs not only to estimate diurnal cycles of climatic data, but to calculate the continuous values of various components in the energy balance equation, using different parameterization methods. The objective of this study is to quantify the impact of the choice of different estimation and parameterization methods, referred together to as meteorological models in this paper, on soil temperature predictions in bare soils. A variety of widely accepted meteorological models were tested on the dataset collected at a proposed low-level radioactive-waste disposal site in the Chihuahua Desert in West Texas. As the soil surface was kept bare during the study, no vegetation effects were evaluated. A coupled liquid water, water vapor, and heat transport model, implemented in the HYDRUS-1D program, was used to simulate diurnal and seasonal soil temperature changes in the engineered cover installed at the site. The modified version of HYDRUS provides a flexible means for using various types of information and different models to evaluate surface mass and energy balance. Different meteorological models were compared in terms of their prediction errors for soil temperatures at seven observation depths. The results obtained indicate that although many available meteorological models can be used to solve the energy balance equation at the soil-atmosphere interface in coupled water, vapor, and heat transport models, their impact on overall simulation results varies. For example, using daily average climatic data led to greater prediction errors, while relatively simple meteorological models may

  9. Regulating drug release from pH- and temperature-responsive electrospun CTS-g-PNIPAAm/poly(ethylene oxide) hydrogel nanofibers

    International Nuclear Information System (INIS)

    Yuan, Huihua; Li, Biyun; Liang, Kai; Lou, Xiangxin; Zhang, Yanzhong

    2014-01-01

    Temperature- and pH-responsive polymers have been widely investigated as smart drug release systems. However, dual-sensitive polymers in the form of nanofibers, which is advantageous in achieving rapid transfer of stimulus to the smart polymeric structures for regulating drug release behavior, have rarely been explored. In this study, chitosan-graft-poly(N-isopropylacrylamide) (CTS-g-PNIPAAm) copolymer was synthesized by using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxy succinimide (NHS) as grafting agents to graft carboxyl-terminated PNIPAAm (PNIPAAm-COOH) chains onto the CTS biomacromolecules, and then CTS-g-PNIPAAm with or without bovine serum albumin (BSA) was fabricated into nanofibers through electrospinning using poly(ethylene oxide) (PEO, 10 wt%) as a fiber-forming facilitating additive. The BSA laden CTS-g-PNIPAAm/PEO hydrogel nanofibers were tested to determine their drug release profiles by varying pH and temperature. Finally, cytotoxicity of the CTS-g-PNIPAAm/PEO hydrogel nanofibers was evaluated by assaying the L929 cell proliferation using the MTT method. It was found that the synthesized CTS-g-PNIPAAm possessed a temperature-induced phase transition and lower critical solution temperature (LCST) at 32° C in aqueous solutions. The rate of BSA release could be well modulated by altering the environmental pH and temperature of the hydrogel nanofibers. The CTS-g-PNIPAAm/PEO hydrogel nanofibers supported L929 cell growth, indicative of appropriate cytocompatibility. Our current work could pave the way towards developing multi-stimuli responsive nanofibrous smart materials for potential applications in the fields of drug delivery and tissue engineering. (paper)

  10. Real-time measurement system for tracking birefringence, weight, thickness, and surface temperature during drying of solution cast coatings and films

    Science.gov (United States)

    Unsal, E.; Drum, J.; Yucel, O.; Nugay, I. I.; Yalcin, B.; Cakmak, M.

    2012-02-01

    This paper describes the design and performance of a new instrument to track temporal changes in physical parameters during the drying behavior of solutions, as well as curing of monomers. This real-time instrument follows in-plane and out-of-plane birefringence, weight, thickness, and surface temperature during the course of solidification of coatings and films through solvent evaporation and thermal or photocuring in a controlled atmosphere. It is specifically designed to simulate behavior of polymer solutions inside an industrial size, continuous roll-to-roll solution casting line and other coating operations where resins are subjected to ultraviolet (UV) curing from monomer precursors. Controlled processing parameters include air speed, temperature, initial cast thickness, and solute concentration, while measured parameters are thickness, weight, film temperature, in-plane and out-of-plane birefringence. In this paper, we illustrate the utility of this instrument with solution cast and dried poly (amide-imide)/DMAc (Dimethylacetamide) solution, water based black paint, and organo-modified clay/NMP (N-Methylpyrrolidone) solution. In addition, the physical changes that take place during UV photo polymerization of a monomer are tracked. This instrument is designed to be generic and it can be used for tracking any drying/swelling/solidification systems including paper, foodstuffs such as; grains, milk as well as pharmaceutical thin paste and slurries.

  11. Experimental determination of contaminant metal mobility as a function of temperature, time and solution chemistry. 1997 annual progress report

    International Nuclear Information System (INIS)

    Bruton, C.; Carroll, S.; O'Day, P.; Sahai, N.

    1997-01-01

    'Strontium is significantly more mobile than other hazardous radioactive metals. Its partitioning between aqueous and solid phases is controlled by reactions that occur at the interface between natural waters and minerals. At a groundwater site in Hanford (200-BP-5), the aerial extent of the 90 Sr plume is 100 times larger than the aerial extent of the 137 Cs and the 239 Pu plumes. Similarly, contaminated, perched watertables at INEL have much higher aqueous concentrations of 90 Sr than 137 Cs, presumably because Cs is preferentially sorbed to solids (Duncan 1995). Under high physical flow conditions, such as those in the highly fractured rock at Hanford and INEL, 90 Sr present in plumes may spread off-site and cause contamination of aquifers or other water sources. Geochemical factors that may contribute to the overall mobility of Sr in natural waters are the solubilities of phases such as strontianite (SrCO 3 ) and formation of strong complexes with sulfate and nitrate. Although 90 Sr is mobilized in natural waters in these examples, significant concentrations may also be present in solid phases. Sorption experiments using a wide variety of substrates at room temperature have shown that Sr is removed from solution under certain conditions. Additionally, strontianite (SrCO 3 ) may precipitate at low Sr concentrations in the pH range of waters in contact with basaltic rocks, which varies between pH 8 and 10. Waters contain variable amounts of carbonate owing to atmospheric interactions; the partial pressure of CO 2 is about 10 x 3.5 atm in air and commonly as high as 10 x 2.5 atm in soils. The objective of this work is to determine the fundamental data needed to predict the behavior of strontium at temperature and time scales appropriate to thermal remediation. The authors approach combines macroscopic sorption/precipitation and desorption/dissolution kinetic experiments, which track changes in solution composition, with direct molecular characterization of

  12. Kinetic Rate Law Parameter Measurements on a Borosilicate Waste Glass: Effect of Temperature, pH, and Solution Composition on Alkali Ion Exchange

    International Nuclear Information System (INIS)

    Pierce, Eric M.; McGrail, B PETER.; Icenhower, J P.; Rodriguez, Elsa A.; Steele, Jackie L.; Baum, Steven R.

    2004-01-01

    The reaction kinetics of glass is controlled by matrix dissolution and ion exchange (IEX). Dissolution of an alkali-rich simulated borosilicate waste glass was investigated using single-pass flow-through (SPFT) experiments. Experiments were conducted as a function of temperature, pH, and solution composition by varying the SiO 2 (aq) activity in the influent solution. Results showed that under dilute conditions matrix dissolution increased with increasing pH and temperature, and decreased with increasing SiO 2 (aq) activity. IEX rates decreased with increasing pH and temperature, and increased with increasing SiO 2 (aq) activity. Over the solution composition range interrogated in this study the dominant dissolution mechanism changed from matrix dissolution to IEX. These results suggest that ''secondary'' reactions may become dominant under certain environmental conditions and emphasize the need to incorporate these reactions into dissolution rate models

  13. Estimation of Hydrazine Decomposition on Measuring the High-Temperature pH in Hydrazine/ETA Solutions at 553 K

    International Nuclear Information System (INIS)

    Hwang, Jae Sik; Yeon, Jei Won; Yun, Myung Hee; Song, Kyu Seok; Lee, Sang Ill

    2010-01-01

    Hydrazine is one of the most excellent oxygen scavengers used in the secondary circuit of nuclear power plants. Furthermore, in some pants, the hydrazine is used as a source of hydrogen required to suppress radiolysis of the coolant water in the primary loop. When hydrazine was exposed in the high temperature and high pressure water, it can be decomposed into the various products such as NH 3 , N 2 , H 2 , and NO 3 ions. As the result, the pH of solution containing hydrazine in the condition of the high temperature and high pressure can be changed by those decomposed products. In the present work, we investigated the decomposition behavior of hydrazine in ETA (ethanol amine) solution. In addition, we measured the high temperature pH at 553 K on the various hydrazine/ETA solutions for confirming the applicability of the yttria stabilized zirconia (YSZ)- based pH electrode in secondary circuit of the nuclear power plants

  14. Modelling of natural convection flows with large temperature differences: a benchmark problem for low Mach number solvers. Part. 1 reference solutions

    International Nuclear Information System (INIS)

    Le Quere, P.; Weisman, C.; Paillere, H.; Vierendeels, J.; Dick, E.; Becker, R.; Braack, M.; Locke, J.

    2005-01-01

    Heat transfer by natural convection and conduction in enclosures occurs in numerous practical situations including the cooling of nuclear reactors. For large temperature difference, the flow becomes compressible with a strong coupling between the continuity, the momentum and the energy equations through the equation of state, and its properties (viscosity, heat conductivity) also vary with the temperature, making the Boussinesq flow approximation inappropriate and inaccurate. There are very few reference solutions in the literature on non-Boussinesq natural convection flows. We propose here a test case problem which extends the well-known De Vahl Davis differentially heated square cavity problem to the case of large temperature differences for which the Boussinesq approximation is no longer valid. The paper is split in two parts: in this first part, we propose as yet unpublished reference solutions for cases characterized by a non-dimensional temperature difference of 0.6, Ra 10 6 (constant property and variable property cases) and Ra = 10 7 (variable property case). These reference solutions were produced after a first international workshop organized by Cea and LIMSI in January 2000, in which the above authors volunteered to produce accurate numerical solutions from which the present reference solutions could be established. (authors)

  15. Influence of Solution Treatment Temperature on Microstructural Properties of an Industrially Forged UNS S32750/1.4410/F53 Super Duplex Stainless Steel (SDSS Alloy

    Directory of Open Access Journals (Sweden)

    Vasile Dănuț Cojocaru

    2017-06-01

    Full Text Available In this present study, the influence of solution annealing temperature on microstructural properties of a forged Super Duplex Stainless Steel (SDSS was investigated by SEM-BSE (Scanning Electron Microscopy-Backscattered Electrons and SEM-EBSD (Scanning Electron Microscopy-Electron Backscatter Diffraction techniques. A brief solution treatment was applied to the forged super duplex alloy, at different temperatures between 800 °C and 1100 °C, with a constant holding time of 0.6 ks (10 min. Microstructural characteristics such as nature, weight fraction, distribution and morphology of constituent phases, average grain-size and grain misorientation were analysed in relation to the solution annealing temperature. Experimental results have shown that the constituent phases in the SDSS alloy are δ-Fe, γ-Fe and σ (Cr-Fe and that their properties are influenced by the solution treatment temperature. SEM examinations revealed microstructural modifications induced by the Cr rich precipitates along the δ/γ and δ/δ grain boundaries, which may significantly affect the toughness and the corrosion resistance of the alloy. Solution annealing at 1100 °C led to complete dissolution of σ (Cr-Fe phase, the microstructure being formed of primary δ-Fe and γ-Fe. The orientation relationship between δ/δ, γ/γ and δ/γ grains was determined by electron back scattering diffraction (EBSD. Both primary constituent phase’s microhardness and global microhardness were determined.

  16. Volumetric, ultrasonic and viscometric studies of solute–solute and solute–solvent interactions of l-threonine in aqueous-sucrose solutions at different temperatures

    International Nuclear Information System (INIS)

    Nain, Anil Kumar; Pal, Renu; Neetu

    2013-01-01

    Highlights: • The study reports density, ultrasonic speed and viscosity data of l-threonine in aqueous-sucrose solutions. • The study elucidates interactions of l-threonine with sucrose in aqueous media. • Provides data to estimate physicochemical properties of proteins in these media. • Correlates physicochemical properties of l-threonine with its behaviour in aqueous-sucrose solutions. -- Abstract: Densities, ρ of solutions of l-threonine in aqueous-sucrose solvents 5%, 10%, 15%, and 20% of sucrose, w/w in water at T = (293.15, 298.15, 303.15, 308.15, 313.15, and 318.15) K; and ultrasonic speeds, u and viscosities, η of these solutions at 298.15, 303.15, 308.15, 313.15, and 318.15 K were measured at atmospheric pressure. From these experimental results, the apparent molar volume, V ϕ , limiting apparent molar volume, V ϕ ∘ and the slope, S v , apparent molar compressibility, K s,ϕ , limiting apparent molar compressibility, K s,ϕ ∘ and the slope, S k , transfer volume, V ϕ,tr ∘ , transfer compressibility, K s,ϕ,tr ∘ , limiting apparent molar expansivity, E ϕ ∘ , Hepler’s constant, (∂ 2 V ϕ ∘ /dT 2 ), Falkenhagen coefficient, A, Jones–Dole coefficient, B and hydration number, n H have been calculated. The results have been interpreted in terms of solute–solvent and solute–solute interactions in these systems. The Gibbs energies of activation of viscous flow per mole of solvent, Δμ 1 ∘number sign and per mole of solute, Δμ 2 ∘number sign were also calculated and discussed in terms of transition state theory. It has been observed that there exist strong solute–solvent interactions in these systems and these interactions increase with increase in sucrose concentration in solution

  17. Kinetics of the oxidation of hydrogen sulfite by hydrogen peroxide in aqueous solution:. ionic strength effects and temperature dependence

    Science.gov (United States)

    Maaß, Frank; Elias, Horst; Wannowius, Klaus J.

    Conductometry was used to study the kinetics of the oxidation of hydrogen sulfite, HSO -3, by hydrogen peroxide in aqueous non-buffered solution at the low concentration level of 10 -5-10 -6 M, typically found in cloud water. The kinetic data confirm that the rate law reported for the pH range 3-6 at higher concentration levels, rate= kH·[H +]·[HSO -3]·[H 2O 2], is valid at the low concentration level and at low ionic strength Ic. At 298 K and Ic=1.5×10 -4 M, third-order rate constant kH was found to be kH=(9.1±0.5)×10 7 M -2 s -1. The temperature dependence of kH led to an activation energy of Ea=29.7±0.9 kJ mol -1. The effect of the ionic strength (adjusted with NaCl) on rate constant kH was studied in the range Ic=2×10 -4-5.0 M at pH=4.5-5.2 by conductometry and stopped-flow spectrophotometry. The dependence of kH on Ic can be described with a semi-empirical relationship, which is useful for the purpose of comparison and extrapolation. The kinetic data obtained are critically compared with those reported earlier.

  18. Solute grain boundary segregation during high temperature plastic deformation in a Cr-Mo low alloy steel

    International Nuclear Information System (INIS)

    Chen, X.-M.; Song, S.-H.; Weng, L.-Q.; Liu, S.-J.

    2011-01-01

    Highlights: → The segregation of P and Mo is evidently enhanced by plastic deformation. → The boundary concentrations of P and Mo increase with increasing strain. → A model with consideration of site competition in grain boundary segregation in a ternary system is developed. → Model predictions show a reasonable agreement with the observations. - Abstract: Grain boundary segregation of Cr, Mo and P to austenite grain boundaries in a P-doped 1Cr0.5Mo steel is examined using field emission gun scanning transmission electron microscopy for the specimens undeformed and deformed by 10% with a strain rate of 2 x 10 -3 s -1 at 900 deg. C, and subsequently water quenched to room temperature. Before deformation, there is some segregation for Mo and P, but the segregation is considerably increased after deformation. The segregation of Cr is very small and there is no apparent difference between the undeformed and deformed specimens. Since the thermal equilibrium segregation has been attained prior to deformation, the segregation produced during deformation has a non-equilibrium characteristic. A theoretical model with consideration of site competition in grain boundary segregation between two solutes in a ternary alloy is developed to explain the experimental results. Model predictions are made, which show a reasonable agreement with the observations.

  19. High temperature creep of single crystals of gold, silver and solid solution gold silver 50-50

    International Nuclear Information System (INIS)

    Dorizzi, Paul

    1973-01-01

    We have studied in compression creep along a direction, single crystals of gold, silver and a 50-50 gold-silver solid solution. The experiments were made at temperatures above 0.7 Tf. We have shown that under these conditions and for these three metals a new slip system is operating: the deformation is due to the slip of dislocations having a 1/2 burgers vector on the {110} planes. For gold the activation energy for creep is equal to the self-diffusion energy. We found the same result for silver when the contribution of divacancies to the self-diffusion energy is taken into account. For the alloy the activation energy for creep is very close to the self-diffusion energy of gold in a 50-50 gold-silver alloy, gold being the slower diffusing species in the alloy. The curves giving the creep rate versus the stress can be fitted with the following laws: ε 0 = σ 5 for gold; ε 0 = σ 2,2 for silver and ε 0 = σ 2,5 for the alloy. The dislocation substructure was studied using the crystalline contrast given by the electron microprobe. This new method gives images which are very sensitive to the sub-grains misorientation. The substructure is made of parallelepipedic cells divided by tilt boundaries that are perpendicular to the {110} slip planes. (author) [fr

  20. Effect of dipotassium hydrogen phosphate on thermodynamic properties of glycine and L-alanine in aqueous solutions at different temperatures

    International Nuclear Information System (INIS)

    Kumar, Harsh; Kaur, Kirtanjot

    2012-01-01

    Highlights: ► Densities and speeds of sound of amino acids in DKHP. ► Apparent molar volume and apparent molar compressibilities were calculated. ► The partial molar expansibilities at infinite dilution φ E 0 were obtained. ► Hydration number n H was calculated. ► The results are discussed in terms of solute–solvent interactions. - Abstract: Densities, ρ, speed of sound, u for glycine, L-alanine have been measured in aqueous solutions of dipotassium hydrogen phosphate (DKHP) ranging from 0.2, 0.4, 0.6 and 0.8 mol·kg −1 at temperatures T = (288.15, 298.15, 308.15 and 318.15) K. The different parameters such as apparent molar volume, limiting apparent molar volume, transfer volume, partial molar expansibility have been derived from density data. Experimental speeds of sound data were used to estimate apparent molar adiabatic compressibility, limiting apparent molar adiabatic compressibility, transfer parameter and hydration number. These parameters have been discussed in the light of ion-ion and ion-solvent interactions.

  1. Low temperature hydrolysis of laboratory tholins in ammonia-water solutions: Implications for prebiotic chemistry on Titan

    Science.gov (United States)

    Neish, Catherine D.; Somogyi, Árpád; Lunine, Jonathan I.; Smith, Mark A.

    2009-05-01

    Laboratory tholins react rapidly in 13 wt% ammonia-water at low temperature, producing complex organic molecules containing both oxygen and altered nitrogen functional groups. These reactions display first-order kinetics with half-lives between 0.3 and 14 days at 253 K. The reaction timescales are much shorter than the freezing timescales of impact melts and volcanic sites on Titan, providing ample time for the formation of oxygenated, possibly prebiotic, molecules on its surface. Comparing the rates of the hydrolysis reactions in ammonia-water to those measured in pure water [Neish, C.D, Somogyi, A., Imanaka, H., Lunine, J.I., Smith, M.A., 2008a. Astrobiology 8, 273-287], we find that incorporation of oxygen into the tholins is faster in the presence of ammonia. The rate increases could be due to the increased pH of the solution, or to the availability of new reaction pathways made possible by the presence of ammonia. Using labeled 15NH 3 water, we find that ammonia does incorporate into some products, and that the reactions with ammonia are largely independent of those with water. A related study in HO18 confirms water as the source of the oxygen incorporated into the oxygen containing products.

  2. Low-temperature transport properties of chemical solution deposited polycrystalline La0.7Sr0.3MnO3 ferromagnetic films under a magnetic field

    International Nuclear Information System (INIS)

    Zhu, Junyu; Chen, Ying; Xu, Wenfei; Yang, Jing; Bai, Wei; Wang, Genshui; Duan, Chungang; Tang, Zheng; Tang, Xiaodong

    2011-01-01

    Polycrystalline La 0.7 Sr 0.3 MnO 3 (LSMO) films were prepared on SiO 2 /Si (001) substrates by chemical solution deposition technique. Electrical and magnetic properties of LSMO were investigated. A minimum phenomenon in resistivity is found at the low temperature ( 0.7 Sr 0.3 MnO 3 films were grown by a modified chemical solution deposition route. → High quality LSMO thin films were prepared directly onto SiO 2 /Si substrates. → Abnormality in resistivity of LSMO films at low temperatures was studied in detail. → The abnormality was mainly attributed to Kondo-like spin dependent scattering.

  3. Effect of solution temperature, light intensity and light in combination with sunlight using mirror duct on growth of leaf lettuce (Lactuca savtiva L. cv. 'Greenwave')

    International Nuclear Information System (INIS)

    Shimizu, H.; Kushida, M.; Fujinuma, W.; Sekine, M.; Kaiho, K.; Arai, H.; Shibusawa, S.

    2004-01-01

    Leaf lettuce crops (Lactuca sativa L. cv. 'Greenwave') were grown in a plant production system using a Mirror Duct which intensified sunlight and transferred it to the inside of buildings. This system was expected to reduce the operational energy and lighting cost. The experiments were conducted under four photosynthetic photon flux densities (PPF) of 140,160, 180, and 200 micro mol mE-2 sE-1, in two light conditions, fluorescent light only and fluorescent light plus sunlight transferred with the Mirror Duct, and were repeated five times in total from August 2002 to July 2003. Five different solution temperatures were finally obtained through all the experiments due to temperature changes inside the experiment facility. Variance was analyzed to estimate the effect of these environmental factors on the growth of leaf lettuce. It was found that the fresh weight of leaf lettuce increased as PPF increased and the rate of increase of weight was 0.6 to 1.0 g per unit PPF in both 17.4 deg C and 23.5 deg C solution temperatures; the solution temperature had a significant effect upon the fresh weight; and a difference in fresh weight at harvest of between 40 and 60 g was observed between 17.4 deg C and 23.5 deg C solution temperatures. The light containing 10% sunlight was not effective for increasing fresh weight at harvest compared to the fluorescent lamp

  4. Effect of temperature on the partial molar volume, isentropic compressibility and viscosity of DL-2-aminobutyric acid in water and in aqueous sodium chloride solutions

    International Nuclear Information System (INIS)

    Romero, Carmen M.; Rodríguez, Diana M.; Ribeiro, Ana C.F.; Esteso, Miguel A.

    2017-01-01

    Highlights: • Apparent volumes, apparent compressibilities, viscosities of DL-2-aminobutyric acid. • Effect of temperature on the values for these properties. • Hydrophobic and hydrophilic interactions and the effect of sodium chloride. - Abstract: Density, sound velocity and viscosity of DL-2-aminobutyric acid in water and in aqueous sodium chloride solutions have been measured at temperatures of (293.15, 298.15, 303.15, 308.15 and 313.15) K. The experimental results were used to determine the apparent molar volume and the apparent molar compressibility as a function of composition at these temperatures. The limiting values of both the partial molar volume and the partial molar adiabatic compressibility at infinite dilution of DL-2-aminobutyric acid in water and in aqueous sodium chloride solutions were determined at each temperature. The experimental viscosity values were adjusted by a least-squares method to a second order equation as proposed by Tsangaris-Martin to obtain the viscosity B coefficient which depends on the size, shape and charge of the solute molecule. The influence of the temperature on the behaviour of the selected properties is discussed in terms of both the solute hydration and the balance between hydrophobic and hydrophilic interactions between the acids and water, and the effect of the sodium chloride concentration.

  5. Electronic setup for fluorescence emission measurements and long-time constant-temperature maintenance of Single-Walled Carbon Nano-Tubes in water solutions

    Directory of Open Access Journals (Sweden)

    De Rosa Matteo

    2017-03-01

    Full Text Available In our previous research we have observed that the fluorescence emission from water solutions of Single-Walled Carbon Nano-Tubes (SWCNT, excited by a laser with a wavelength of 830nm, diminishes with the time. We have already proved that such a fading is a function of the storage time and the storage temperature. In order to study the emission of the SWCNT as a function of these two parameters we have designed and realized a special measurement compartment with a cuvette holder where the SWCNT solutions can be measured and stored at a fixed constant temperature for periods of time as long as several weeks. To maintain the measurement setup under a constant temperature we have designed special experimental setup based on two Peltier cells with electronic temperature control.

  6. Effects of Fructose and Temperature on the Micellization of a Cationic Gemini Surfactant, Pentanediyl-1,5-bis(dimethylcetylammonium) Bromide in Aqueous Solutions

    Science.gov (United States)

    Alam, Md. Sayem; Mohammed Siddiq, A.; Mandal, Asit Baran

    2017-12-01

    By the conductivity measurements the effects of fructose and temperature (293-308 K) on the micellization of a cationic gemini surfactant (GS), pentanediyl-1,5-bis(dimethylcetylammonium) bromide in aqueous solutions have been investigated. The critical micelle concentration (CMC) of GS was measured at the different temperatures and fructose concentrations. An increasing trend of the CMC values is with addition of fructose. With increasing temperature, the CMC values are in a similar increasing trend. The CMC of GS by dye solubilization method at room temperature have been determined. The standard Gibbs energy, enthalpy and entropy of GS micellization have been evaluated. From these thermodynamic parameters, it was found that in presence of fructose, the stability of the GS aqueous solutions decreases.

  7. Density and viscosity study of nicotinic acid and nicotinamide in dilute aqueous solutions at and around the temperature of the maximum density of water

    International Nuclear Information System (INIS)

    Dhondge, Sudhakar S.; Dahasahasra, Prachi N.; Paliwal, Lalitmohan J.; Deshmukh, Dinesh W.

    2014-01-01

    Highlights: • Volumetric and transport behaviour of aqueous solutions of important vitamins are reported. • Various interactions of nicotinic acid and nicotinamide with water have been reported. • The temperature dependence of interactions between solute and solvent is discussed. • The study indicates that nicotinamide is more hydrated as compared to nicotinic acid. - Abstract: In the present study, we report experimental densities (ρ) and viscosities (η) of aqueous solutions of nicotinic acid and nicotinamide within the concentration range (0 to 0.1) mol · kg −1 at T = (275.15, 277.15 and 279.15) K. These parameters are then used to obtain thermodynamic and transport functions such as apparent molar volume of solute (V ϕ ), limiting apparent molar volume of solute (V ϕ 0 ), limiting apparent molar expansivity of solute (E ϕ 0 ), coefficient of thermal expansion (α ∗ ), Jones–Dole equation viscosity A, B and D coefficients, temperature derivative of B coefficient i.e. (dB/dT) and hydration number (n H ), etc. The activation parameters of viscous flow for the binary mixtures have been determined and discussed in terms of Eyring’s transition state theory. These significant parameters are helpful to study the structure promoting or destroying tendency of solute and various interactions present in (nicotinic acid + water) and (nicotinamide + water) binary mixtures

  8. Application of the van der Waals equation of state to polymers .4. Correlation and prediction of lower critical solution temperatures for polymer solutions

    DEFF Research Database (Denmark)

    Goncalves, Ana Saraiva; Kontogeorgis, Georgios; Harismiadis, Vassilis I.

    1996-01-01

    The van der Waals equation of state is used for the correlation and the prediction of the lower critical solution behavior or mixtures including a solvent and a polymer. The equation of state parameters for the polymer are estimated from experimental volumetric data at low pressures. The equation...

  9. Physical nature of structural and phase transformations in Cu-Al α solid solutions upon low-temperature irradiation and subsequent annealing

    Science.gov (United States)

    Petrenko, P. V.; Kulish, N. P.; Mel'nikova, N. A.; Grabovskii, Yu. E.

    2013-12-01

    Methods of X-ray diffraction analysis and measurements of residual resistivity have been used to study effects of electron irradiation in the temperature range of 250-330 K on the structural and phase state of the Cu-15 at % Al solid solution. The results obtained are explained by the presence in the Cu-Al alloys of an inhomogeneous short-range order of two types, i.e., low-temperature, α2 type; and high-temperature, γ2 type.

  10. Influence of temperature, chloride ions and chromium element on the electronic property of passive film formed on carbon steel in bicarbonate/carbonate buffer solution

    Energy Technology Data Exchange (ETDEWEB)

    Li, D.G. [School of Materials Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Tubular Goods Research Center of CNPC, Xi' an 710065 (China)], E-mail: dangguoli78@yahoo.com.cn; Feng, Y.R.; Bai, Z.Q. [Tubular Goods Research Center of CNPC, Xi' an 710065 (China); Zhu, J.W.; Zheng, M.S. [School of Materials Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

    2007-11-01

    The influences of temperature, chloride ions and chromium element on the electronic property of passive film formed on carbon steel in NaHCO{sub 3}/Na{sub 2}CO{sub 3} buffer solution are investigated by capacitance measurement and electrochemical impedance spectroscopy (EIS). The results show that the passive film appears n-type semiconductive character; with increasing the solution temperature, the addition of chromium into carbon steel and increasing the concentration of chloride ions, the slopes of Mott-Schottky plots decrease, which indicates the increment of the defect density in the passive film. EIS results show that the transfer impedance R{sub 1} and the diffusion impedance W decrease with increasing the solution temperature, with the addition of chromium into carbon steel and with increasing the chloride ions concentration. It can be concluded that the corrosion protection effect of passive film on the substrate decreases with increasing the solution temperature, adding chromium into carbon steel and increasing chloride ions concentration.

  11. Combined Effect of Temperature and pKa on the Kinetics of Absorption of Carbon Dioxide in Aqueous Alkanolamine and Carbonate Solutions with Carbonic Anhydrase

    NARCIS (Netherlands)

    Penders-Van Elk, Nathalie J M C; Oversteegen, S. Martijn; Versteeg, Geert F.

    2016-01-01

    In present work the absorption of carbon dioxide in aqueous N-methyldiethanolamine, N,N-dimethylethanolamine, and triisopropanolamine solutions with and without the enzyme carbonic anhydrase has been studied in a stirred cell reactor at temperatures varying between 278 and 313 K, at an alkanolamine

  12. Coexistence of room temperature ferroelectricity and ferrimagnetism in multiferroic BiFeO3-Bi0.5Na0.5TiO3 solid solution

    International Nuclear Information System (INIS)

    Tian, Z.M.; Wang, C.H.; Yuan, S.L.; Wu, M.S.; Ma, Z.Z.; Duan, H.N.; Chen, L.

    2011-01-01

    Highlights: → In this study, the coexistence of ferroelectrics and ferrimagnetism have been observed at room temperature for the (1 - x)BiFeO 3 -xBi 0.5 Na 0.5 TiO 3 (x = 0.37) solid solutions. → X-ray diffraction and Raman spectroscopy measurements show a single-phase perovskite structure with no impurities identified. → A magnetic transition from paramagnetic (PM) to ferrimagnetic (Ferri) ordering is observed for the solution with Curie temperature T C ∼ 330 K. - Abstract: The structure, ferroelectric and magnetic properties of (1 - x)BiFeO 3 -xBi 0.5 Na 0.5 TiO 3 (x = 0.37) solid solution fabricated by a sol-gel method have been investigated. X-ray diffraction and Raman spectroscopy measurements show a single-phase perovskite structure with no impurities identified. Compared with pure BiFeO 3 , the coexistence of ferroelectricity and ferrimagnetism have been observed at room temperature for the solution with remnant polarization P r = 1.41 μC/cm 2 and remnant magnetization M r = 0.054 emu/g. Importantly, a magnetic transition from ferrimagnetic (FM) ordering to paramagnetic (PM) state is observed, with Curie temperature T C ∼ 330 K, being explained in terms of the suppression of cycloid spin configuration by the structural distortion.

  13. Influence of pH, temperature, and concentration on stabilization of aqueous hornet silk solution and fabrication of salt-free materials.

    Science.gov (United States)

    Kameda, Tsunenori

    2015-01-01

    We found that an aqueous solution of silk from cocoons produced by hornet larvae (hornet silk) can be obtained when the solution is adjusted to basic conditions of pH > 9.2. It is known that native hornet cocoons can be dissolved in concentrated aqueous solution of salts, such as lithium bromide (LiBr) and calcium chloride (CaCl2). Upon the removal of these salts from solution by dialysis, solidification, gelation, or sedimentation of hornet silk is known to occur. In the present study, under basic conditions, however, no such solidification occurred, even after salt removal. In this study, ammonia was used for alkalization of solution because it is volatilized during the casting process and pure hornet silk materials can be obtained after drying. The effects of the concentrations of hornet silk and ammonia, as well as dialysis temperature, on preventing gelation during dialysis were investigated. Dialysis conditions that limit the degradation of hornet silk by hydrolysis in alkali solution were identified. Moreover, casting conditions to prepare flexible and transparent hornet silk film from aqueous ammonia solution were optimized. Molecular structural analysis of hornet silk in aqueous ammonia solution and cast film indicated the formation of α-helix conformations. © 2014 Wiley Periodicals, Inc.

  14. The analytical solution to the problem on the temperature field in a structural element of rectangular profile for third kind boundary conditions

    International Nuclear Information System (INIS)

    Kulich, N.V.; Nemtsev, V.A.

    1986-01-01

    The analytical solution to the problem on the stationary temperature field in an infinite structural element of rectangular profile characteristic of the conjugation points of a vessel and a tube sheet of a heat exchanger (or of a finned surface) at the third-kind boundary conditions has been obtained by the methods of the complex variable function theory. With the help of the obtained analytical dependences the calculations of the given element of the design and the comparison with the known data have been conducted. The proposed analytical solution can be effectively used in calculations of temperature fields in finned surfaces and structural elements of the power equipment of the considered profile and the method is applied for solution of the like problems

  15. Analytical solutions for the temperature field in a 2D incompressible inviscid flow through a channel with walls of solid fuel

    Directory of Open Access Journals (Sweden)

    Sorin BERBENTE

    2011-12-01

    Full Text Available A gas (oxidizer flows between two parallel walls of solid fuel. A combustion is initiated: the solid fuel is vaporized and a diffusive flame occurs. The hot combustion products are submitted both to thermal diffusion and convection. Analytical solutions can be obtained both for the velocity and temperature distributions by considering an equivalent mean temperature where the density and the thermal conductivity are evaluated. The main effects of heat transfer are due to heat convection at the flame. Because the detailed mechanism of the diffusion flame is not introduced the reference chemical reaction is the combustion of premixed fuel with oxidizer in excess. In exchange the analytical solution is used to define an ideal quasi-uniform combustion that could be realized by an n adequate control. The given analytical closed solutions prove themselves flexible enough to adjust the main data of some existing experiments and to suggest new approaches to the problem.

  16. Effect of sodium phosphate salts on the thermodynamic properties of aqueous solutions of poly(ethylene oxide) 6000 at different temperatures

    International Nuclear Information System (INIS)

    Sadeghi, Rahmat; Hosseini, Rahim; Jamehbozorg, Bahman

    2008-01-01

    Precise density, sound velocity, water activity, and phase diagram measurements have been carried out on polyethylene oxide (PEO) in aqueous solutions of sodium di-hydrogen phosphate, di-sodium hydrogen phosphate, and tri-sodium phosphate over a range of temperatures at atmospheric pressure. The experimental density and sound velocity data are used to calculate the apparent specific volume and isentropic compressibility as a function of temperature and concentration. It was found that both of the apparent specific volume and isentropic compressibility of PEO in aqueous solutions increase by increasing temperature and charge on the anion of electrolytes. The results show that the slope of constant water activity lines increased with increasing the temperature and charge on the anion of electrolytes and the vapour pressure depression for an aqueous (PEO + sodium phosphate) system is more than the sum of those for the corresponding binary solutions. Furthermore, the effect of temperature and type of anion of salt on the salting-out effect of polyethylene oxide by sodium phosphate salts has been studied

  17. Effect of sodium phosphate salts on the thermodynamic properties of aqueous solutions of poly(ethylene oxide) 6000 at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, Rahmat [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)], E-mail: rahsadeghi@yahoo.com; Hosseini, Rahim; Jamehbozorg, Bahman [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

    2008-09-15

    Precise density, sound velocity, water activity, and phase diagram measurements have been carried out on polyethylene oxide (PEO) in aqueous solutions of sodium di-hydrogen phosphate, di-sodium hydrogen phosphate, and tri-sodium phosphate over a range of temperatures at atmospheric pressure. The experimental density and sound velocity data are used to calculate the apparent specific volume and isentropic compressibility as a function of temperature and concentration. It was found that both of the apparent specific volume and isentropic compressibility of PEO in aqueous solutions increase by increasing temperature and charge on the anion of electrolytes. The results show that the slope of constant water activity lines increased with increasing the temperature and charge on the anion of electrolytes and the vapour pressure depression for an aqueous (PEO + sodium phosphate) system is more than the sum of those for the corresponding binary solutions. Furthermore, the effect of temperature and type of anion of salt on the salting-out effect of polyethylene oxide by sodium phosphate salts has been studied.

  18. High temperature aqueous potassium and sodium phosphate solutions: two-liquid-phase boundaries and critical phenomena, 275-4000C; potential applications for steam generators

    International Nuclear Information System (INIS)

    Marshall, W.L.

    1981-12-01

    Two-liquid-phase boundaries at temperatures between 275 and 400 0 C were determined for potassium phosphate and sodium phosphate aqueous solutions for compositions from 0 to 60 wt % dissolved salt. The stoichiometric mole ratios, K/PO 4 or Na/PO 4 , were varied from 1.00 to 2.12 and from 1.00 to 2.16 for the potassium and sodium systems, respectively. Liquid-vapor critical temperatures were also determined for most of the dilute liquid phases that formed. The minimum temperatures (below which a single solution existed) of two-liquid-phase formation were 360 0 C for the potassium system and 279 0 C for the sodium system at mole ratios of 2.00 and 2.16, respectively. For the sodium system at mole ratios greater than 2.16, solids crystallized at lower temperatures as expected from earlier studies. In contrast, potassium solutions that were explored at mole ratios from 2.12 to 3.16 and at temperatures below 360 0 C did not produce solid phases nor liquid-liquid immiscibilities. Aside from the generally unusual observations of two immiscible liquids in an aqueous inorganic salt system, the results could possibly be applied to the use of phosphate additives in steam power generators. 16 refs

  19. Experimental determination of the isothermal (vapour + liquid) equilibria of binary aqueous solutions of sec-butylamine and cyclohexylamine at several temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Chiali-Baba Ahmed, Nouria [LATA2M, Laboratoire de Thermodynamique Appliquee et Modelisation Moleculaire, University AbouBekr Belkaid of Tlemcen, Post Office Box 119, Tlemcen 13000 (Algeria); Negadi, Latifa, E-mail: latifanegadi@yahoo.fr [LATA2M, Laboratoire de Thermodynamique Appliquee et Modelisation Moleculaire, University AbouBekr Belkaid of Tlemcen, Post Office Box 119, Tlemcen 13000 (Algeria); Mokbel, Ilham [LSA, Laboratoire des Sciences Analytiques, CNRS-UMR 5280, Universite Claude Bernard - Lyon I, 43, Bd du 11 Novembre 1918, Villeurbanne Cedex 69622 (France); Kaci, Ahmed Ait [Laboratoire de Thermodynamique et Modelisation Moleculaire, Universite des Sciences et de la Technologie Houari Boumediene, Post Office Box 32, El Alia 16111, Bab Ezzouar (Algeria); Jose, Jacques [LSA, Laboratoire des Sciences Analytiques, CNRS-UMR 5280, Universite Claude Bernard - Lyon I, 43, Bd du 11 Novembre 1918, Villeurbanne Cedex 69622 (France)

    2012-01-15

    Highlights: > Vapour pressures of sec-butylamine or cyclohexylamine and their aqueous solutions. > The investigated temperatures are 273 K and 363 K. > The (cyclohexylamine + water) mixture shows positive azeotropic behaviour. > The (sec-butylamine + water) or (cyclohexylamine + water) exhibit positive G{sup E}. - Abstract: The vapour pressures of (sec-butylamine + water), (cyclohexylamine + water) binary mixtures, and of pure sec-butylamine and cyclohexylamine components were measured by means of two static devices at temperatures between 293 (or 273) K and 363 K. The data were correlated with the Antoine equation. From these data, excess Gibbs functions (G{sup E}) were calculated for several constant temperatures and fitted to a fourth-order Redlich-Kister equation using the Barker's method. The (cyclohexylamine + water) system shows positive azeotropic behaviour for all investigated temperatures. The two binary mixtures exhibit positive deviations in G{sup E} for all investigated temperatures over the whole composition range.

  20. Applicability test of glass lining material for high-temperature acidic solutions of sulfuric acid in thermochemical water-splitting IS process

    International Nuclear Information System (INIS)

    Iwatsuki, Jin; Tanaka, Nobuyuki; Terada, Atsuhiko; Onuki, Kaoru; Watanabe, Yutaka

    2010-01-01

    A key issue for realizing the thermochemical IS process for hydrogen production is the selection of materials for working with high-temperature acidic solutions of sulfuric acid and hydriodic acid. Glass lining material is a promising candidate, which is composed of steel having good strength and glass having good corrosion resistance. Since the applicability of glass lining material depends strongly on the service condition, corrosion tests using glass used in glass lining material and heat cycle tests using glass lining piping were carried out to examine the possibility of using the glass lining material with high-temperature acidic solutions of sulfuric acid. It was confirmed that the glass lining materials exhibited sufficient corrosion resistance and heat resistance in high-temperature sulfuric acid of the IS process. (author)

  1. Crystallization of urea from an evaporative aqueous solution sessile droplet at sub-boiling temperatures and surfaces with different wettability

    NARCIS (Netherlands)

    Schmid, J.; Zarikos, I.; Terzis, A.; Roth, N.; Weigand, B.

    The injection of urea-water-solution sprays in the exhaust pipe of modern diesel engines eliminates NOx emissions in a very great extent. However, as water evaporates from the solution, urea is crystallized and causes walldeposit formations hindering the performance of selective-catalytic-reaction.

  2. Room-temperature solution-processed and metal oxide-free nano-composite for the flexible transparent bottom electrode of perovskite solar cells

    Science.gov (United States)

    Lu, Haifei; Sun, Jingsong; Zhang, Hong; Lu, Shunmian; Choy, Wallace C. H.

    2016-03-01

    The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through an all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite composed of a silver nano-network and graphene oxide (GO) flawless film for the transparent bottom electrode of a PVSC. Our experimental results show that the amount of GO flakes play a critical role in forming the flawless anti-corrosive barrier in the silver nano-network through a self-assembly approach under ambient atmosphere, which can effectively prevent the penetration of liquid or gaseous halides and their corrosion against the silver nano-network underneath. Importantly, we simultaneously achieve good work function alignment and surface wetting properties for a practical bottom electrode by controlling the degree of reduction of GO flakes. Finally, flexible PVSC adopting the room-temperature and solution-processed nano-composite as the flexible transparent bottom electrode has been demonstrated on a polyethylene terephthalate (PET) substrate. As a consequence, the demonstration of our room-temperature solution-processed and metal oxide-free flexible transparent bottom electrode will contribute to the emerging large-area flexible PVSC technologies.The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through an all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite composed of a silver nano-network and graphene oxide (GO) flawless film for the transparent bottom electrode of a PVSC. Our experimental results show that the amount of GO flakes play a critical role in forming the flawless anti-corrosive barrier in the silver nano-network through a self

  3. Energy, economy and exergy evaluations of the solutions for supplying domestic hot water from low-temperature district heating in Denmark

    International Nuclear Information System (INIS)

    Yang, Xiaochen; Li, Hongwei; Svendsen, Svend

    2016-01-01

    Highlights: • Provided domestic hot water configurations for low-temperature district heating. • Various building typologies and district heating supply temperatures were included. • Different scenarios were evaluated from the energy, economy and exergy aspects. • The benefits of lower return temperature to district heating were investigated. - Abstract: District heating in Denmark is going through the transition from 3rd generation (80/40 °C) to 4th generation (50–55 °C/25 °C) systems in preparation for district heating based completely on renewable fuels by 2035. However, concern about Legionella growth and reduced comfort with low-temperature domestic hot water supply may be discouraging the implementation of low-temperature district heating. Aimed at providing possible solutions, this study modelled various proposals for district heating systems with supply temperatures of 65 °C, 50 °C and 35 °C and for two different building topologies. Evaluation models were built to investigate the energy, economy and exergy performances of the proposed domestic hot water systems in various configurations. The configurations of the devised domestic hot water substations were optimised to fit well with both low and ultra-low-temperature district heating and to reduce the return temperature to district heating. The benefits of lower return temperatures were also analysed compared with the current district heating situation. The evaluation results show that the decentralized substation system with instantaneous heat exchanger unit performed better under the 65 °C and 50 °C district heating scenarios, while the individual micro tank solution consumed less energy and cost less in the 35 °C district heating scenario.

  4. A study on in vitro culture of Trichuris ovis in different physiological solutions at constant temperature, 37°C.

    Science.gov (United States)

    Singh, Tikam; Lal, S S

    2011-06-01

    The primary aim of in vitro culture of whipworms (Trichuris ovis) is to provide artificial conditions under which the life cycle of the parasites completed outside the host under controlled conditions. The physiological solutions used for the present study were sodium chloride (0.64%), Ringer's solution, Tyrode's solution, and Lock-Lewis solution. Parasites were collected from freshly slaughtered intestine of the host. The recovered parasites were washed with running tap water after that with normal saline. After washing parasites were put in four petridishes containing different physiological solutions. Observations were recorded after interval of every 8 h. The hundred percent survival of Trichuris ovis was observed at 32, 40, and 48 h in NaCl (0.64%), Ringer's, Tyrode's, and Lock-Lewis solution, respectively in case of both male and female parasites. In sodium chloride solution (0.64%) cent percent mortality was observed after 64 h of incubation in males and in case of females it was observed 72 h. In Ringer's solution cent percent mortality was observed after 72 in males and in females it was observed 80 h. In Tyrode's solution cent percent mortality was observed after 88 h in males and 96 h in females. In Lock-Lewis solution cent percent mortality was observed after 96 h in case of both the male and female parasites. Present study could be used to understand the effects of various drugs on the above parasites and also other intra-intestinal parasites.

  5. Effect of temperature gradient in the solution on spiral growth of YBa2Cu3O7-x bulk single crystals

    International Nuclear Information System (INIS)

    Kanamori, Y.; Shiohara, Y.

    1996-01-01

    Bulk single crystals of Y123 are required to clarify the superconductivity phenomena and develop electronic devices using unique superconductive properties. Only the Solute Rich Liquid endash Crystal Pulling (SRL-CP) method has succeeded in continuous growth of the Y123 single crystal. In this paper, we investigated the growth of Y123 single crystals under different temperature gradients in the solution in order to understand the growth mechanism of Y123. It was revealed that Y123 single crystals grow with a spiral growth mode, which is in good agreement with the BCF theory. copyright 1996 Materials Research Society

  6. Isobaric specific heat capacity of water and aqueous cesium chloride solutions for temperatures between 298 K and 370 K at p = 0.1 MPa

    International Nuclear Information System (INIS)

    Lourenco, M.J.V.; Santos, F.J.V.; Ramires, M.L.V.; Nieto de Castro, C.A.

    2006-01-01

    There has been some controversy regarding the uncertainty of measurements of thermal properties using differential scanning calorimeters, namely heat capacity of liquids. A differential scanning calorimeter calibrated in enthalpy and temperature was used to measure the isobaric specific heat capacity of water and aqueous solutions of cesium chloride, in the temperature range 298 K to 370 K, for molalities up 3.2 mol . kg -1 , at p = 0.1 MPa, with an estimated uncertainty (ISO definition) better than 1.1%, at a 95% confidence level. The measurements are completely traceable to SI units of energy and temperature. The results obtained were correlated as a function of temperature and molality and compared with other authors, obtained by different methods and permit to conclude that a DSC calibrated by Joule effect is capable of very accurate measurements of the isobaric heat capacity of liquids, traceable to SI units of measurement

  7. Energy, economy and exergy evaluations of the solutions for supplying domestic hot water from low-temperature district heating in Denmark

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Li, Hongwei; Svendsen, Svend

    2016-01-01

    District heating in Denmark is going through the transition from 3rd generation (80/40 °C) to 4th generation (50-55 °C/25 °C) systems in,preparation for district heating based completely on renewable fuels by 2035. However, concern about Legionella growth and reduced comfort with low......-temperature domestic hot water supply may be discouraging the implementation of low-temperature district heating. Aimed at providing possible solutions, this study modelled various proposals for district heating systems with supply temperatures of 65 °C, 50 °C and 35 °C and for two different building topologies....... Evaluation models were built to investigate the energy, economy and exergy performances of the proposed domestic hot water systems in various configurations. The configurations of the devised domestic hot water substations were optimised to fit well with both low and ultra-low-temperature district heating...

  8. Density, thermal expansion coefficient and viscosity of sodium tetraborate (borax)-UO2 and of sodium metaborate-UO2 solutions at high temperatures

    International Nuclear Information System (INIS)

    Dalle Donne, M.; Dorner, S.; Roth, A.

    1983-01-01

    Measurements have been performed of the density, of the volumetric thermal expansion coefficient and of the viscosity of liquid sodium tetraborate (borax) and of sodium metaborate both pure and with two different amounts of UO 2 dissolved in each. The viscosity measurements have been performed for the solution of sodium tetraborate with UO 2 and CeO 2 , and with CeO 2 only as well. These data are required for the design of core-catchers based on sodium borates. The density measurements have been performed with the buoyancy method in the temperature range from 825 0 C to 1300 0 C, the viscosity measurements in the temperature range 700-1250 0 C with a modified Haake viscosity balance. The balance was previously calibrated at ambient temperature with a standard calibration liquid and at high temperatures, with data for pure borax available from the literature. (orig.)

  9. Effect of the synthesis temperature of sodium nona-titanate on batch kinetics of strontium-ion adsorption from aqueous solution

    International Nuclear Information System (INIS)

    Merceille, A.; Weinzaepfel, E.; Grandjean, A.; Merceille, A.; Weinzaepfel, E.; Barre, Y.

    2011-01-01

    Sodium titanate materials are promising inorganic ion exchangers for the adsorption of strontium from aqueous solutions. Sodium nona-titanate exhibits a layered structure consisting of titanate layers and exchangeable sodium ions between the layers. The materials used in this study include samples synthesized by a hydrothermal method at temperatures between 60 degrees C and 200 degrees C. Their structure, composition, and morphology were investigated with X-Ray diffraction measurements; thermogravimetric, compositional and surface area analyses, and scanning electron microscopy. The structure, composition, and morphology depended on the synthesis temperature. Batch kinetics experiments for the removal of strontium from aqueous solutions were performed, and the data were fitted by a pseudo-second-order reaction model and a diffusive model. The strontium extraction capacity also depended on the synthesis temperature and exhibited a maximum for samples synthesized at 100 degrees C. The sorption process occurs in one or two diffusion-controlled steps that also depend on the synthesis temperature. These diffusion-limited steps are the boundary-layer diffusion and intra-particle diffusion in the case of pure nona-titanate synthesized at temperatures lower than 170 degrees C, and only intra-particle diffusion in the case of nona-titanate synthesized at 200 degrees C. (authors)

  10. Fluid temperature at the corneal endothelium during phacoemulsification: comparison of an ophthalmic viscosurgical device and balanced salt solution using the finite element method.

    Science.gov (United States)

    Reepolmaha, Somporn; Limtrakarn, Wiroj; Uthaisang-Tanechpongtamb, Wanlaya; Dechaumphai, Pramote

    2010-01-01

    The purpose of this study was to estimate and compare the temperatures of two different anterior chamber solutions at the corneal endothelial level during phacoemulsification. An ophthalmic viscosurgical device (OVD) and balanced salt solution (BSS) were compared using the finite element method (FEM). The thermal properties of an OVD (IAL-F) and BSS were studied in an experimental setting. A computer-aided design model of ocular anatomy was created in two dimensions. The phaco needle was considered to be the only source of heat generation. Then, the FEM was used to demonstrate the transient temperature distribution in the two ocular models at 10, 20, 30, 40, 50 and 60 s. In these models, the anterior chamber was filled with IAL-F (IAL-F model) or BSS (BSS model). The heat generation rate of the phaco needle was 0.0004 cal/s/mm(2). The maximum corneal endothelial temperatures for the two models at 60 s were 52.67 and 41.57 degrees C, respectively. The experimental IAL-F model showed fewer changes in temperature for any given time and location. At larger distances from the heat source, less temperature variation was detected. Phacoemulsification is a potential heat-generating procedure performed between the delicate anterior chamber structures. During this procedure, IAL-F protects the endothelium against heat better than BSS. Copyright 2009 S. Karger AG, Basel.

  11. Temperature dependence of water-water and ion-water correlations in bulk water and electrolyte solutions probed by femtosecond elastic second harmonic scattering

    Science.gov (United States)

    Chen, Yixing; Dupertuis, Nathan; Okur, Halil I.; Roke, Sylvie

    2018-06-01

    The temperature dependence of the femtosecond elastic second harmonic scattering (fs-ESHS) response of bulk light and heavy water and their electrolyte solutions is presented. We observe clear temperature dependent changes in the hydrogen (H)-bond network of water that show a decrease in the orientational order of water with increasing temperature. Although D2O has a more structured H-bond network (giving rise to more fs-ESHS intensity), the relative temperature dependence is larger in H2O. The changes are interpreted in terms of the symmetry of H-bonds and are indicators of nuclear quantum effects. Increasing the temperature in electrolyte solutions decreases the influence of the total electrostatic field from ions on the water-water correlations, as expected from Debye-Hückel theory, since the Debye length becomes longer. The effects are, however, 1.9 times (6.3 times) larger than those predicted for H2O (D2O). Since fs-ESHS responses can be computed from known molecular coordinates, our observations provide a unique opportunity to refine quantum mechanical models of water.

  12. Temperature-assisted solute focusing with sequential trap/release zones in isocratic and gradient capillary liquid chromatography: Simulation and experiment

    Science.gov (United States)

    Groskreutz, Stephen R.; Weber, Stephen G.

    2016-01-01

    In this work we characterize the development of a method to enhance temperature-assisted on-column solute focusing (TASF) called two-stage TASF. A new instrument was built to implement two-stage TASF consisting of a linear array of three independent, electronically controlled Peltier devices (thermoelectric coolers, TECs). Samples are loaded onto the chromatographic column with the first two TECs, TEC A and TEC B, cold. In the two-stage TASF approach TECs A and B are cooled during injection. TEC A is heated following sample loading. At some time following TEC A’s temperature rise, TEC B’s temperature is increased from the focusing temperature to a temperature matching that of TEC A. Injection bands are focused twice on-column, first on the initial TEC, e.g. single-stage TASF, then refocused on the second, cold TEC. Our goal is to understand the two-stage TASF approach in detail. We have developed a simple yet powerful digital simulation procedure to model the effect of changing temperature in the two focusing zones on retention, band shape and band spreading. The simulation can predict experimental chromatograms resulting from spatial and temporal temperature programs in combination with isocratic and solvent gradient elution. To assess the two-stage TASF method and the accuracy of the simulation well characterized solutes are needed. Thus, retention factors were measured at six temperatures (25–75 °C) at each of twelve mobile phases compositions (0.05–0.60 acetonitrile/water) for homologs of n-alkyl hydroxylbenzoate esters and n-alkyl p-hydroxyphenones. Simulations accurately reflect experimental results in showing that the two-stage approach improves separation quality. For example, two-stage TASF increased sensitivity for a low retention solute by a factor of 2.2 relative to single-stage TASF and 8.8 relative to isothermal conditions using isocratic elution. Gradient elution results for two-stage TASF were more encouraging. Application of two-stage TASF

  13. Study of Temperature Effect on the Corrosion Inhibition of C38 Carbon Steel Using Amino-tris(Methylenephosphonic Acid in Hydrochloric Acid Solution

    Directory of Open Access Journals (Sweden)

    Najoua Labjar

    2011-01-01

    Full Text Available Tafel polarization method was used to assess the corrosion inhibitive and adsorption behaviours of amino-tris(methylenephosphonic acid (ATMP for C38 carbon steel in 1 M HCl solution in the temperature range from 30 to 60∘C. It was shown that the corrosion inhibition efficiency was found to increase with increase in ATMP concentration but decreased with temperature, which is suggestive of physical adsorption mechanism. The adsorption of the ATMP onto the C38 steel surface was found to follow Langmuir adsorption isotherm model. The corrosion inhibition mechanism was further corroborated by the values of kinetic and thermodynamic parameters obtained from the experimental data.

  14. Equilibrium solubility of CO{sub 2} in aqueous solutions of 1-amino-2-propanol as function of concentration, temperature, and pressure

    Energy Technology Data Exchange (ETDEWEB)

    Rebolledo-Morales, Miguel Angel; Rebolledo-Libreros, Maria Esther [Instituto Mexicano del Petroleo, Direccion de Investigacion y Posgrado, Programa de Ingenieria Molecular, Area de Investigacion de Termofisica, Eje Central Lazaro Cardenas Norte 152, 07730 Mexico, D.F. (Mexico); Trejo, Arturo, E-mail: atrejo@imp.m [Instituto Mexicano del Petroleo, Direccion de Investigacion y Posgrado, Programa de Ingenieria Molecular, Area de Investigacion de Termofisica, Eje Central Lazaro Cardenas Norte 152, 07730 Mexico, D.F. (Mexico)

    2011-05-15

    Research highlights: Gas solubility of CO{sub 2} in aqueous solutions of 1-amino-2-propanol was measured. Solubility increases as pressure and concentration of 1-amino-2-propanol increase. The Kent-Eisenberg model was used to correlate all the experimental results. Aqueous solutions of MIPA are an excellent alternative to use in gas purification. - Abstract: Using a dynamic method with recirculation of the vapour phase, experimental values for the gas solubility of carbon dioxide in aqueous solutions of 1-amino-2-propanol (MIPA) were measured at T = (313.15 and 393.15) K, over the pressure range of (0.2 to 2436.4) kPa. The concentrations of the studied aqueous MIPA solutions were (0.20, 0.30, 0.40, and 0.50) mass fraction. The results of gas solubility are given as the partial pressure of CO{sub 2}, p{sub CO{sub 2}}, against its mole ratio, {alpha}{sub CO{sub 2}} (mol CO{sub 2} {center_dot} mol{sup -1} MIPA), and its mole fraction, x{sub CO{sub 2}}. It is observed that the solubility of CO{sub 2} increases as the concentration of MIPA in solution increases, at a given temperature throughout the pressure range considered; also the solubility values increase, under constant temperature, as the pressure increases in the studied concentration range of MIPA. The physicochemical model of Kent and Eisenberg was used to correlate simultaneously all the experimental results of the solubility of CO{sub 2} in the studied aqueous solutions of MIPA. The model correlates satisfactorily the experimental results. The deviation for pressure was 96.9 kPa using 62 experimental solubility points. The solubility results of carbon dioxide presented in this work are compared with those reported in the literature for aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), diisopropanolamine (DIPA), and N-methyldiethanolamine (MDEA) and it is possible to conclude that the aqueous solutions of MIPA are an excellent alternative to use in gas purification processes, since the

  15. Perturbation Solutions for Hagen-Poiseuille Flow and Heat Transfer of Third-Grade Fluid with Temperature-Dependent Viscosities and Internal Heat Generation

    Directory of Open Access Journals (Sweden)

    B. Y. Ogunmola

    2016-01-01

    Full Text Available Regular perturbation technique is applied to analyze the fluid flow and heat transfer in a pipe containing third-grade fluid with temperature-dependent viscosities and heat generation under slip and no slip conditions. The obtained approximate solutions were used to investigate the effects of slip on the heat transfer characteristics of the laminar flow in a pipe under Reynolds’s and Vogel’s temperature-dependent viscosities. Also, the effects of parameters such as variable viscosity, non-Newtonian parameter, viscous dissipation, and pressure gradient at various values were established. The results of this work were compared with the numerical results found in literature and good agreements were established. The results can be used to advance the analysis and study of the behavior of third-grade fluid flow and steady state heat transfer processes such as those found in coal slurries, polymer solutions, textiles, ceramics, catalytic reactors, and oil recovery applications.

  16. Programmable pH buffers

    Science.gov (United States)

    Gough, Dara Van; Huber, Dale L.; Bunker, Bruce C.; Roberts, Mark E.

    2017-01-24

    A programmable pH buffer comprises a copolymer that changes pK.sub.a at a lower critical solution temperature (LCST) in water. The copolymer comprises a thermally programmable polymer that undergoes a hydrophobic-to-hydrophilic phase change at the LCST and an electrolytic polymer that exhibits acid-base properties that are responsive to the phase change. The programmable pH buffer can be used to sequester CO.sub.2 into water.

  17. The effect of temperature and concentration on the corrosion inhibition mechanism of an amphiphilic amido-amine in CO2 saturated solution

    OpenAIRE

    Desimone, Paula Mariela; Gordillo, Gabriel Jorge; Simison, Silvia Noemi

    2017-01-01

    The corrosion inhibition mechanism of the N-[2-[(2-aminoethyl)amino]ethyl]-9-octadecenamide on mild steel surface in CO2-saturated 5% NaCl solution has been studied. The inhibition efficiency decreases with increasing temperature. Adsorption of the inhibitor studied is found to follow the Frumkin adsorption isotherm. EIS results show that the mechanism of its corrosion inhibition at concentrations higher than critical micelle concentration is by forming a protective porous bi-layer. The a...

  18. Determination of Three-Dimensional Morphology and Inner Structure of Second-Phase Inclusions in Metals by Non-Aqueous Solution Electrolytic and Room Temperature Organic Methods

    OpenAIRE

    Jing Guo; Keming Fang; Hanjie Guo; Yiwa Luo; Shengchao Duan; Xiao Shi; Wensheng Yang

    2018-01-01

    The secondary-phase particles in metals, particularly those composed of non-metallic materials, are often detrimental to the mechanical properties of metals; thus, it is crucial to control inclusion formation and growth. One of the challenges is determining the three-dimensional morphology and inner structures of such inclusions. In this study, a non-aqueous solution electrolytic method and a room-temperature organic technique were developed based on the principle of electrochemistry to deter...

  19. A rapid method for measuring maximum density temperatures in water and aqueous solutions for the study of quantum zero point energy effects in these liquids

    International Nuclear Information System (INIS)

    Deeney, F A; O'Leary, J P

    2008-01-01

    The connection between quantum zero point fluctuations and a density maximum in water and in liquid He 4 has recently been established. Here we present a description of a simple and rapid method of determining the temperatures at which maximum densities in water and aqueous solutions occur. The technique is such as to allow experiments to be carried out in one session of an undergraduate laboratory thereby introducing students to the concept of quantum zero point energy

  20. Energy, economy and exergy evaluations of the solutions for supplying domestic hot water from low-temperature district heating in Denmark

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Li, Hongwei; Svendsen, Svend

    2016-01-01

    . Evaluation models were built to investigate the energy, economy and exergy performances of the proposed domestic hot water systems in various configurations. The configurations of the devised domestic hot water substations were optimised to fit well with both low and ultra-low-temperature district heating...... °C and 50 °C district heating scenarios, while the individual micro tank solution consumed less energy and cost less in the 35 °C district heating scenario....

  1. NMR study of temperature-induced phase separation and polymer-solvent interactions in poly(vinyl methyl ether)/D.sub.2./sub.O/ethanol solutions

    Czech Academy of Sciences Publication Activity Database

    Hanyková, L.; Labuta, J.; Spěváček, Jiří

    2006-01-01

    Roč. 47, č. 17 (2006), s. 6107-6116 ISSN 0032-3861 Grant - others:GA UK 294/2004/B Institutional research plan: CEZ:AV0Z40500505 Keywords : poly(vinyl methyl ether)/D2O/ ethanol solutions * temperature-induced phase separation * 1H and 13C NMR spectroscopy Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.773, year: 2006

  2. Reduction of the Curie temperature in the multiferroic Bi5Fe1+xTi3−xO15 solid solution

    International Nuclear Information System (INIS)

    Salazar-Kuri, U; Mendoza, M E; Silva, R; Siqueiros, J M; Gervacio-Arciniega, J J

    2014-01-01

    In this work, the phase diagram of the system Bi 4 Ti 3 O 12 -BiFeO 3 in the region of the solid solution Bi 5 Fe 1+x Ti 3−x O 15 was refined. The limit of solubility was determined to be at x = 0.1. The Curie temperature (T C ) of the ferroelectric phase transition was determined by dielectric permittivity measurements at 100 kHz for the phase Bi 5 FeTi 3 O 15 as well as for the solid solution. A decrease in T C from 750 °C to 742 °C (solid solution at x = 0.1) was found. These results can be explained in terms of the perturbation of the oxygen octahedral perovskite layers resulting from the substitution of Ti 4+ by Fe 3+ ions. (paper)

  3. Insight about electrical properties of low-temperature solution-processed Al-doped ZnO nanoparticle based layers for TFT applications

    Energy Technology Data Exchange (ETDEWEB)

    Diallo, Abdou Karim; Gaceur, Meriem; Fall, Sadiara; Didane, Yahia; Ben Dkhil, Sadok; Margeat, Olivier, E-mail: margeat@cinam.univ-mrs.fr; Ackermann, Jörg; Videlot-Ackermann, Christine, E-mail: videlot@cinam.univ-mrs.fr

    2016-12-15

    Highlights: • Al-doped ZnO (AZO) nanoparticles. • Impact of dispersion state and solid state on electrical properties. • Extrinsic doping with Al for high conducting AZO nanoparticle based layers. • Low-temperature operating nanoparticulate AZO TFTs. - Abstract: Aluminium-doped zinc oxide nanoparticles (NPs) with controlled Al doping contents (AZO{sub x} with x = 0–0.8 at% of Al) were explored as new oxide semiconductor materials to study the impact of doping on both solution and solid states. Polycrystalline AZO{sub x} thin films were produced by spin-coating the dispersions following by a thermal post-treatment at low-temperature (80 °C or 150 °C). The coated AZO{sub x} films were employed as active layer in thin-film transistors. Morphology and microstructure were studied by scanning electron microscopy and X-ray diffraction. The impact on the device performances (mobility, conductivity, charge carrier density) of Al-doping content together with the solution state was examined. Spin-coated films delivered an electron mobility up to 3 × 10{sup −2} cm{sup 2}/Vs for the highest Al-doping ratio AZO{sub 0.8}. Despite highly different morphologies, extrinsic doping with aluminium significantly increases the conductivity of low temperature solution-processed AZO{sub x} NPs series based layers by several orders of magnitude from AZO{sub 0} to AZO{sub 0.8}.

  4. Highly uniform resistive switching properties of amorphous InGaZnO thin films prepared by a low temperature photochemical solution deposition method.

    Science.gov (United States)

    Hu, Wei; Zou, Lilan; Chen, Xinman; Qin, Ni; Li, Shuwei; Bao, Dinghua

    2014-04-09

    We report on highly uniform resistive switching properties of amorphous InGaZnO (a-IGZO) thin films. The thin films were fabricated by a low temperature photochemical solution deposition method, a simple process combining chemical solution deposition and ultraviolet (UV) irradiation treatment. The a-IGZO based resistive switching devices exhibit long retention, good endurance, uniform switching voltages, and stable distribution of low and high resistance states. Electrical conduction mechanisms were also discussed on the basis of the current-voltage characteristics and their temperature dependence. The excellent resistive switching properties can be attributed to the reduction of organic- and hydrogen-based elements and the formation of enhanced metal-oxide bonding and metal-hydroxide bonding networks by hydrogen bonding due to UV irradiation, based on Fourier-transform-infrared spectroscopy, X-ray photoelectron spectroscopy, and Field emission scanning electron microscopy analysis of the thin films. This study suggests that a-IGZO thin films have potential applications in resistive random access memory and the low temperature photochemical solution deposition method can find the opportunity for further achieving system on panel applications if the a-IGZO resistive switching cells were integrated with a-IGZO thin film transistors.

  5. Temperature-assisted On-column Solute Focusing: A General Method to Reduce Pre-column Dispersion in Capillary High Performance Liquid Chromatography

    Science.gov (United States)

    Groskreutz, Stephen R.; Weber, Stephen G.

    2014-01-01

    Solvent-based on-column focusing is a powerful and well known approach for reducingthe impact of pre-column dispersion in liquid chromatography. Here we describe an orthogonal temperature-based approach to focusing called temperature-assisted on-column solute focusing (TASF). TASF is founded on the same principles as the more commonly used solvent-based method wherein transient conditions are created thatlead to high solute retention at the column inlet. Combining the low thermal mass of capillary columns and the temperature dependence of solute retentionTASF is used effectivelyto compress injection bands at the head of the column through the transient reduction in column temperature to 5 °C for a defined 7 mm segment of a 6 cm long 150 μm I.D. column. Following the 30 second focusing time, the column temperature is increased rapidly to the separation temperature of 60 °C releasing the focused band of analytes. We developed a model tosimulate TASF separations based on solute retention enthalpies, focusing temperature, focusing time, and column parameters. This model guides the systematic study of the influence of sample injection volume on column performance.All samples have solvent compositions matching the mobile phase. Over the 45 to 1050 nL injection volume range evaluated, TASF reducesthe peak width for all soluteswith k’ greater than or equal to 2.5, relative to controls. Peak widths resulting from injection volumes up to 1.3 times the column fluid volume with TASF are less than 5% larger than peak widths from a 45 nL injection without TASF (0.07 times the column liquid volume). The TASF approach reduced concentration detection limits by a factor of 12.5 relative to a small volume injection for low concentration samples. TASF is orthogonal to the solvent focusing method. Thus, it canbe used where on-column focusing is required, but where implementation of solvent-based focusing is difficult. PMID:24973805

  6. Development and Characterization of Improved NiTiPd High-Temperature Shape-Memory Alloys by Solid-Solution Strengthening and Thermomechanical Processing

    Science.gov (United States)

    Bigelow, Glen; Noebe, Ronald; Padula, Santo, II; Garg, Anita; Olson, David

    2006-01-01

    The need for compact, solid-state actuation systems for use in the aerospace, automotive, and other transportation industries is currently motivating research in high-temperature shape-memory alloys (HTSMA) with transformation temperatures greater than 100 C. One of the basic high-temperature alloys investigated to fill this need is Ni(19.5)Ti(50.5)Pd30. Initial testing has indicated that this alloy, while having acceptable work characteristics, suffers from significant permanent deformation (or ratcheting) during thermal cycling under load. In an effort to overcome this deficiency, various solid-solution alloying and thermomechanical processing schemes were investigated. Solid-solution strengthening was achieved by substituting 5at% gold or platinum for palladium in Ni(19.5)Ti(50.5)Pd30, the so-called baseline alloy, to strengthen the martensite and austenite phases against slip processes and improve thermomechanical behavior. Tensile properties, work behavior, and dimensional stability during repeated thermal cycling under load for the ternary and quaternary alloys were compared. The relative difference in yield strength between the martensite and austenite phases and the dimensional stability of the alloy were improved by the quaternary additions, while work output was only minimally impacted. The three alloys were also thermomechanically processed by cycling repeatedly through the transformation range under a constant stress. This so-called training process dramatically improved the dimensional stability in these samples and also recovered the slight decrease in work output caused by quaternary alloying. An added benefit of the solid-solution strengthening was maintenance of enhanced dimensional stability of the trained material to higher temperatures compared to the baseline alloy, providing a greater measure of over-temperature capability.

  7. Specific features of kinetics of He/sup 3/-He/sup 4/ solid solution transformations at superlow temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Mikheev, V A; Majdanov, V A; Mikhin, N P

    1986-06-01

    The NMR data on the phase transition kinetics of /sup 3/He-/sup 4/He solid solutions at T=100 mK are considered. Studied are solid helium samples of a molecular volume of 20.55 cm/sup 2//mol with a /sup 3/He content of 0.54%. An unusually long phase transition time is found which is dependent on the prehistory of sample. The spin diffusion of /sup 3/He in the transformated solution concentrated phase is found to be of a quasi-one-dimensional nature with the diffusion coefficient value typical of liquid.

  8. (p,V{sub m},T,x) measurements for aqueous LiNO{sub 3} solutions[Density; Concentration; Electrolyte solutions; Equation of state; Lithium nitrate; Saturated density; Saturated pressure; Temperature; Water

    Energy Technology Data Exchange (ETDEWEB)

    Abdulagatov, I.M. E-mail: ilmutdin@boulder.nist.govmangur@datacom.ru; Azizov, N.D. E-mail: Nazim_Azizov@yahoo.com

    2004-01-01

    (p,V{sub m},T,x) properties of four aqueous LiNO{sub 3} solutions (0.181, 0.526, 0.963, and 1.728) mol {center_dot} kg{sup -1} H{sub 2}O were measured in the liquid phase with a constant-volume piezometer immersed in a precision liquid thermostat. Measurements were made for 10 isotherms between (298 and 573) K. The range of pressure was from (2 to 40) MPa. The total uncertainty of density, pressure, temperature, and concentration measurements were estimated to be less than 0.06 %, 0.05 %, 10 mK, and 0.014 %, respectively. The values of saturated density were determined by extrapolating experimental (p,{rho}) data to the vapor-pressure at fixed temperature and composition using an interpolating equation. A polynomial type of equation of state for specific volume was obtained as a function of temperature, pressure, and composition by a least-squares method from the experimental data. The average absolute deviation (AAD) between measured and calculated values from this polynomial equation for density was 0.02 %. Measured values of solution density were compared with values calculated from Pitzer's ion-interaction equation. The agreement is within (0.2 to 0.4) % depending of concentration range.

  9. Synthesis of fast response crosslinked PVA-g-NIPAAm nanohydrogels by very low radiation dose in dilute aqueous solution

    International Nuclear Information System (INIS)

    Fathi, Marziyeh; Reza Farajollahi, Ali; Akbar Entezami, Ali

    2013-01-01

    Nanohydrogels of poly(vinyl alcohol)-g-N-isopropylacrylamide (PVA-g-NIPAAm) are synthesized by PVA and NIPAAm dilute aqueous solution using much less radiation dose of 1–20 Gy via intramolecular crosslinking at ambient temperature. The radiation synthesis of nanohydrogels is performed in the presence of tetrakis (hydroxymethyl) phosphonium chloride (THPC) due to its rapid oxygen scavenging abilities and hydrogen peroxide (H 2 O 2 ) as a source of hydroxyl radicals. The effect of radiation dose, feed composition ratio of PVA and H 2 O 2 is investigated on swelling properties such as temperature and pH dependence of equilibrium swelling ratio as well as deswelling kinetics. Experimental data exhibit high equilibrium swelling ratio and fast response time for the synthesized nanohydrogels. The average molecular weight between crosslinks (M c ) and crosslinking density (ρ x ) of the obtained nanohydrogels are calculated from swelling data as a function of radiation dose, H 2 O 2 and PVA amount. Fourier transform infrared spectroscopy (FT-IR), elemental analysis of nitrogen content and thermogravimetric analysis (TGA) are used to confirm the grafting reaction. Lower critical solution temperature (LCST) is measured around 33 °C by differential scanning calorimetry (DSC) for PVA-g-NIPAAm nanohydrogels. Dynamic light scattering (DLS) data demonstrate that the increase of radiation dose leads to the decreasing in dimension of nanohydrogels. Also, rheological studies are confirmed an improvement in the mechanical properties of the nanohydrogels with increasing the radiation dose. A cytotoxicity study exhibits a good biocompatibility for the obtained nanohydrogels. The prepared nanohydrogels show fast swelling/deswelling behavior, high swelling ratio, dual sensitivity and good cytocompatibility, which may find potential applications as biomaterial. - Highlights: ► A new radiation polymerization method is offered in dilute aqueous solution.► This method provides PVA

  10. Solution-Grown CsPbBr3 /Cs4 PbBr6 Perovskite Nanocomposites: Toward Temperature-Insensitive Optical Gain.

    Science.gov (United States)

    Wang, Yue; Yu, Dejian; Wang, Zeng; Li, Xiaoming; Chen, Xiaoxuan; Nalla, Venkatram; Zeng, Haibo; Sun, Handong

    2017-09-01

    With regards to developing miniaturized coherent light sources, the temperature-insensitivity in gain spectrum and threshold is highly desirable. Quantum dots (QDs) are predicted to possess a temperature-insensitive threshold by virtue of the separated electronic states; however, it is never observed in colloidal QDs due to the poor thermal stability. Besides, for the classical II-VI QDs, the gain profile generally redshifts with increasing temperature, plaguing the device chromaticity. Herein, this paper addresses the above two issues simultaneously by embedding ligands-free CsPbBr 3 nanocrystals in a wider band gap Cs 4 PbBr 6 matrix by solution-phase synthesis. The unique electronic structures of CsPbBr 3 nanocrystals enable temperature-insensitive gain spectrum while the lack of ligands and protection from Cs 4 PbBr 6 matrix ensure the thermal stability and high temperature operation. Specifically, a color drift-free stimulated emission irrespective of temperature change (20-150 °C) upon two-photon pumping is presented and the characteristic temperature is determined to be as high as ≈260 K. The superior gain properties of the CsPbBr 3 /Cs 4 PbBr 6 perovskite nanocomposites are directly validated by a vertical cavity surface emitting laser operating at temperature as high as 100 °C. The results shed light on manipulating optical gain from the advantageous CsPbBr 3 nanocrystals and represent a significant step toward the temperature-insensitive frequency-upconverted lasers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Acid-base buffering in organ preservation solutions as a function of temperature: new parameters for comparing buffer capacity and efficiency.

    Science.gov (United States)

    Baicu, Simona C; Taylor, Michael J

    2002-08-01

    Control of acidity and preventing intracellular acidosis are recognized as critical properties of an effective organ preservation solution. Buffer capacity and efficiency are therefore important for comparing the relative merits of preservation fluids for optimum hypothermic storage, but these parameters are not available for the variety of organ preservation solutions of interest in transplantation today. Moreover, buffer capacity is dependent upon both concentration and pH such that buffer capacity is not easily predicted for a complex solution containing multiple buffer species. Using standard electrometric methods to measure acid dissociation constants, this study was undertaken to determine the maximum and relative buffer capacities of a variety of new and commonly used hypothermic preservation solutions as a function of temperature. The reference data provided by these measurements show that comparative buffer capacity and efficiency vary widely between the commonly used solutions. Moreover, the fluids containing zwitterionic sulfonic acid buffers such as Hepes possess superior buffering for alpha-stat pH regulation in the region of physiological importance.

  12. A novel low-temperature chemical solution route for straight and dendrite-like ZnO nanostructures

    International Nuclear Information System (INIS)

    Zhang Hui; Du Ning; Wu Jianbo; Ma, Xiangyang; Yang Deren; Zhang Xiaobin; Yang Zhiqing

    2007-01-01

    The straight and dendrite-like growths of ZnO have been completely and simply controlled by the status of ZnO seed instead of surfactant, template, oriented attachment, and ZnO buffer layer on the substrate in the chemical reaction synthesis of ZnO nanostructures. The monodisperse ZnO seeds, which are prepared by in situ quickly injecting the cool mixed zinc acetate and potassium hydrate ethanol solution into the hot matrix aqueous solution of zinc nitrate hydrate and diethylenetriamine at 95 deg. C, improve the straight growth and lots of uniform, straight, and single-crystalline ZnO nanorods with about 20-30 nm in diameter and 300 nm in length are achieved. While, the aggregated ZnO seeds, which are prepared by dropwise adding potassium hydrate ethanol solution into zinc acetate ethanol solution at 60 deg. C for 3 h, result in the dendrite-like growth and the bur-like ZnO nanostructures consisting of hundreds of nanorods with about 30-50 nm in diameter and several micrometers in length are formed. Furthermore, the approach presented here provides a simple, low-cost, environmental-friendly and high efficiency route to synthesize the high quality ZnO nanorods and bur-like ZnO nanostructures

  13. Physicochemical Behavior of Some Amino Acids/Glycylglycine in Aqueous D-Galactose Solutions at Different Temperatures

    Science.gov (United States)

    Ali, Anwar; Patel, Rajan; Shahjahan; Ansari, Nizamul Haque

    2010-03-01

    The apparent molar volumes {(overline{V_2})} for glycine (Gly), l-alanine (Ala), phenylalanine (Phe), and glycylglycine (Gly-Gly) in 0.10 m aqueous d-galactose solutions have been determined from density measurements at (298.15, 303.15, 308.15, and 313.15) K. The data for {(overline{V_2})} were utilized to estimate the partial molar volume at infinite dilution {(overline{V_2^0})} , and experimental slope {(S_v^ast)} . The transfer volume, {(overline{V2^0}_(tr))} , and hydration number, ( n H) were also evaluated. The viscosity data were used to evaluate A- and B-coefficients of the Jones-Dole equation, the free energy of activation of viscous flow per mole of the solvent {left(Δ μ1^{0ast} right)} and the solute {left(Δ μ 2^{0ast} right)} . The molar refractivity ( R D) was calculated from refractive index data. The results were discussed in terms of hydrophilic-ionic, hydrophilic-hydrophobic, and hydrophobic-hydrophobic interactions, and structure-making/-breaking ability of the solute (AAs/peptide) in aqueous d-galactose solutions.

  14. EUV lithographic radiation grafting of thermo-responsive hydrogel nanostructures

    International Nuclear Information System (INIS)

    Farquet, Patrick; Padeste, Celestino; Solak, Harun H.; Guersel, Selmiye Alkan; Scherer, Guenther G.; Wokaun, Alexander

    2007-01-01

    Nanostructures of the thermoresponsive poly(N-isopropyl acrylamide) (PNIPAAm) and of PNIPAAm-block-poly(acrylic acid) copolymers were produced on poly(tetrafluoroethylene-co-ethyelene) (ETFE) films using extreme ultraviolet (EUV) lithographic exposure with subsequent graft-polymerization. The phase transition of PNIPAAm nanostructures at the low critical solution temperature (LCST) at 32 deg. C was imaged by atomic force microscopy (AFM) phase contrast measurements in pure water. Results show a higher phase contrast for samples measured below the LCST temperature than for samples above the LCST, proving that the soft PNIPAAm hydrogel transforms into a much more compact conformation above the LCST. EUV lithographic exposures were combined with the reversible addition-fragment chain transfer (RAFT)-mediated polymerization using cyanoisopropyl dithiobenzoate (CPDB) as chain transfer agent to synthesize PNIPAAm block-copolymer nanostructures

  15. Rate constants and temperature effects for reactions of Cl2sm-bullet- with unsaturated alcohols and hydrocarbons in aqueous and acetonitrile/water solutions

    International Nuclear Information System (INIS)

    Padmaja, S.; Neta, P.; Huie, R.E.

    1992-01-01

    Absolute rate constants for reactions of the dichlorine radical anion, Cl 2 sm-bullet- , with unsaturated alcohols and hydrocarbons have been measured at various temperatures. The alcohol reactions were measured in aqueous solutions and the hydrocarbon reactions in 1:1 aqueous acetonitirle (ACN) solutions. The rate constants for two alcohols and one hydrocarbon were also examined as a function of solvent composition. The room temperature rate constants varied between 10 6 and 10 9 M -1 s -1 . The pre-exponential factors, A, were about (1-5) x 10 9 M -1 s -1 for the alcohols in aqueous solutions and about (0.1-1) x 10 9 M -1 s -1 for the hydrocarbons in aqueous ACN solutions. The activation energies, E a , varied considerably, between 4 and 12 kJ mol -1 for the alcohols and between 2 and 8 kJ mol -1 for the hydrocarbons. The rate constants, k 298 , decrease with increasing ionization potential (IP) of the unsaturated compound, in agreement with an electrophilic addition mechanism. The activation energies for the unsaturated alcohols decrease when the IP decreases from 9.7 to 9.1 eV but appear to level off at lower IP. Most alkenes studied had IP a . Upon addition of ACN to the aqueous solution, the values of log k 298 decreased linearly by more than 1 order of magnitude with increasing ACN mole fraction. This decrease appears to result from a combination of changes in the activation energy and in the pre-exponential factor. The reason for these changes may lie in changes in the solvation shell of the Cl 2 sm-bullet- radical, which will affect the A factor, in combination with changes in solvation of Cl - , which will affect the energetics of the reactions as well. 20 refs., 7 figs., 6 tabs

  16. Thermodynamic study of Eu3+/Eu2+ redox reaction in aqueous solutions at elevated temperatures and pressures by means of cyclic voltametry

    International Nuclear Information System (INIS)

    Bilal, B.A.

    1991-01-01

    The redox potential of the couple Eu 3+ /E 2+ in aqueous NaCl, NaClO 4 and Na 2 SO 4 solutions of different strength and various pH values has been determined by means of cyclic voltammetry up to 458 K and 1 kbar. In all cases reversible voltammograms were obtained. Compared to the redox potential in ClO 4 - solutions of pH 2, no significant shift was observed in Cl-solutions of the same pH, whereas a drastic shift to more negative potentials in solutions of SO 4 2- and in Cl - solutions of higher pH (pH 3-5) was obtained. This indicates a negligible complexation of Eu 3+ by means of Cl - but a strong one by means of OH - and SO 4 2- . An isothermal pressure increase up to 1 kbar led to a shift of only few mV more negative, indicating a small pressure dependence of the change of the partial molar volume (ΔV el ) accompanying the redox reaction, which results in this case only due to the different degrees of electrostriction. A more drastic shift of the redox potential (in the positive direction) results with increasing temperature. The isobaric temperature dependence of the redox potential is described by a two parameter equation which remains valid up to the saturation pressure at 458 K, due to the small pressure effect. ΔS and ΔH of the redox reaction has been determined. (orig.)

  17. Phase equilibrium properties of binary aqueous solutions containing ethanediamine, 1,2-diaminopropane, 1,3-diaminopropane, or 1,4-diaminobutane at several temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Nouria Chiali-Baba [LATA2M, Laboratoire de Thermodynamique Appliquee et Modelisation Moleculaire, University AbouBekr Belkaid of Tlemcen, P.O. Box 119, Tlemcen 13000 (Algeria); Negadi, Latifa, E-mail: l_negadi@mail.univ-tlemcen.d [LATA2M, Laboratoire de Thermodynamique Appliquee et Modelisation Moleculaire, University AbouBekr Belkaid of Tlemcen, P.O. Box 119, Tlemcen 13000 (Algeria); Mokbel, Ilham; Jose, Jacques [LSA, Laboratoire des Sciences Analytiques, CNRS-UMR 5180, Universite Claude Bernard - Lyon I. 43, Bd du 11 Novembre 1918, Villeurbanne Cedex 69622 (France)

    2011-05-15

    Research highlights: Vapour pressures of ethanediamine (EDA), 1,2-diaminopropane, 1,3-diaminopropane (1,3-DAP), or 1,4-diaminobutane (1,4-DAB) aqueous solutions are reported between (293 and 363) K. The two first mixtures show negative azeotropic behaviour. The aqueous solutions of EDA, 1,2-DAP, or 1,3-DAP exhibit negative G{sup E} whereas the one containing 1,4-DAB shows either negative G{sup E} or sinusoidal shape for G{sup E}. - Abstract: The vapour pressures of {l_brace}ethanediamine (EDA) + water{r_brace}, {l_brace}1,2-diaminopropane (1,2-DAP) + water{r_brace}, {l_brace}1,3-diaminopropane (1,3-DAP) + water{r_brace} or {l_brace}1,4-diaminobutane (1,4-DAB) + water{r_brace} binary mixtures, and of pure EDA, 1,2-DAP, 1,3-DAP, 1,4-DAB, and water components were measured by means of two static devices at temperatures between (293 and 363) K. The data were correlated with the Antoine equation. From these data, the excess Gibbs function (G{sup E}) was calculated for several constant temperatures and fitted to a fourth-order Redlich-Kister equation using the Barker's method. The {l_brace}ethanediamine (EDA) + water{r_brace}, and {l_brace}1,2-diaminopropane (1,2-DAP) + water{r_brace} binary systems show negative azeotropic behaviour. The aqueous solutions of EDA, 1,2-DAP, or 1,3-DAP exhibit negative deviations in G{sup E} for all investigated temperatures over the whole composition range whereas the (1,4-DAB + water) binary mixture shows negative G{sup E} for temperatures (293.15 < T/K < 353.15) and a sinusoidal shape for G{sup E} at T = 363.15 K.

  18. High-temperature, Knudsen cell-mass spectroscopic studies on lanthanum oxide/uranium dioxide solid solutions

    International Nuclear Information System (INIS)

    Sunder, S.; McEachern, R.; LeBlanc, J.C.

    2001-01-01

    Knudsen cell-mass spectroscopic experiments were carried out with lanthanum oxide/uranium oxide solid solutions (1%, 2% and 5% (metal at.% basis)) to assess the volatilization characteristics of rare earths present in irradiated nuclear fuel. The oxidation state of each sample used was conditioned to the 'uranium dioxide stage' by heating in the Knudsen cell under an atmosphere of 10% CO 2 in CO. The mass spectra were analyzed to obtain the vapour pressures of the lanthanum and uranium species. It was found that the vapour pressure of lanthanum oxide follows Henry's law, i.e., its value is directly proportional to its concentration in the solid phase. Also, the vapour pressure of lanthanum oxide over the solid solution, after correction for its concentration in the solid phase, is similar to that of uranium dioxide. (authors)

  19. Crevice-corrosion kinetics on titanium and a Ti-Ni-Mo alloy in chloride solutions at elevated temperature

    International Nuclear Information System (INIS)

    McKay, P.

    1987-01-01

    The results of an electrochemical investigation of the crevice-corrosion kinetics on titanium and a dilute Ti-Ni-Mo alloy (0.8% Ni, 0.3% Mo), in concentrated chloride solutions at 150 0 C, are presented. The current-time transients, obtained on creviced electrodes under both potentiostatic and galvanic (coupling to a large area of uncreviced titanium) conditions, are interpreted in terms of crevice acidification leading to the formation of an active-passive cell, maintained by iR gradient in the electrolyte. The passivating effect of the Ni and Mo additions on the crevice corrosion of titanium are described, together with the results of an electrochemical study, carried out in bulk acid chloride solutions, that were used to substantiate a proposed mechanism of crevice passivation. (author)

  20. High temperature thermodynamics of H2 and D2 in titanium, and in dilute titanium oxygen solid solutions

    International Nuclear Information System (INIS)

    Dantzer, P.

    1983-01-01

    The Tian Calvet microcalorimetric method has been improved in order to determine ΔH-barsub(H)(D), the partial molar enthalpy of mixing of hydrogen (deuterium) in the Ti-H 2 (D 2 ) solid systems for compositions 0 2 solid solutions (y = (O/Ti)) at 745 K. The combined calorimetric and equilibrium method allows a precise evaluation of the partial molar entropies. The results of this study differ substantially from earlier published data. (author)

  1. SOLUBILITIES AND PHYSICAL PROPERTIES OF SATURATED SOLUTIONS IN THE COPPER SULFATE + SULFURIC ACID + SEAWATER SYSTEM AT DIFFERENT TEMPERATURES

    OpenAIRE

    Justel, F. J.; Claros, M.; Taboada, M. E.

    2015-01-01

    Abstract In Chile, the most important economic activity is mining, concentrated in the north of the country. This is a desert region with limited water resources; therefore, the mining sector requires research and identification of alternative sources of water. One alternative is seawater, which can be a substitute of the limited fresh water resources in the region. This work determines the influence of seawater on the solid-liquid equilibrium for acid solutions of copper sulfate at different...

  2. Effect of precursor solutions stirring on deep level defects concentration and spatial distribution in low temperature aqueous chemical synthesis of zinc oxide nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Alnoor, Hatim, E-mail: hatim.alnoor@liu.se; Chey, Chan Oeurn; Pozina, Galia; Willander, Magnus; Nur, Omer [Department of Science and Technology (ITN), Campus Norrköping, Linköping University, SE-601 74 Norrköping (Sweden); Liu, Xianjie; Khranovskyy, Volodymyr [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-583 81 Linköping (Sweden)

    2015-08-15

    Hexagonal c-axis oriented zinc oxide (ZnO) nanorods (NRs) with 120-300 nm diameters are synthesized via the low temperature aqueous chemical route at 80 °C on silver-coated glass substrates. The influence of varying the precursor solutions stirring durations on the concentration and spatial distributions of deep level defects in ZnO NRs is investigated. Room temperature micro-photoluminesnce (μ-PL) spectra were collected for all samples. Cathodoluminescence (CL) spectra of the as-synthesized NRs reveal a significant change in the intensity ratio of the near band edge emission (NBE) to the deep-level emission (DLE) peaks with increasing stirring durations. This is attributed to the variation in the concentration of the oxygen-deficiency with increasing stirring durations as suggested from the X-ray photoelectron spectroscopy analysis. Spatially resolved CL spectra taken along individual NRs revealed that stirring the precursor solutions for relatively short duration (1-3 h), which likely induced high super saturation under thermodynamic equilibrium during the synthesis process, is observed to favor the formation of point defects moving towards the tip of the NRs. In contrary, stirring for longer duration (5-15 h) will induce low super saturation favoring the formation of point defects located at the bottom of the NRs. These findings demonstrate that it is possible to control the concentration and spatial distribution of deep level defects in ZnO NRs by varying the stirring durations of the precursor solutions.

  3. In-situ Raman spectroscopic study of aluminate speciation in H2O-KOH solutions at high pressures and temperatures

    Science.gov (United States)

    Mookherjee, M.; Keppler, H.; Manning, C. E.

    2009-12-01

    The solubility of corundum in H2O is low even at high pressure and temperatures. Therefore, it is commonly assumed that alumina remains essentially immobile during fluid-rock interaction. However, field and experimental evidence suggests that alumina solubility is strongly enhanced in the presence of silica as well as in alkaline solutions. In order to understand what controls the alumina solubility and how it is enhanced as a function of fluid composition, we conducted Raman-spectroscopic study of Al speciation in aqueous fluids at high pressure and temperature. Experiments were carried out in an externally heated hydrothermal diamond-anvil cell equipped with low-fluorescence diamonds and iridium gaskets. Raman spectra were collected with a Horiba Jobin-Yvon Labram HR spectrometer using the 514 nm line of an argon laser for excitation. In a first series of experiments, the speciation of alumina was studied in a 1 M KOH solution in equilibrium with corundum up to 700 oC and ~1 GPa. The Raman spectra show a prominent band at 618 cm-1 interpreted to arise from Al-O stretching vibrations associated with the tetrahedral [Al(OH)4]1- species. At higher pressure and temperature, an additional vibrational mode appears in the spectra at 374 cm-1 (full width at half maximum ~ 20 cm-1). This feature is tentatively attributed to [(OH)3Al-O-Al(OH)3]2- (Moolenaar et al. 1970, Jour. Phys. Chem., 74, 3629-3636). No evidence for KAl(OH)4 was observed, consistent with piston cylinder experiments at 700 oC and 1 GPa (Wohlers & Manning, 2009, Chem. Geol., 262, 310). Upon cooling from high-pressure and high temperature, slow kinetics of corundum regrowth lead to oversaturation in the solutions, as evidenced by sharp peaks at 930 and 1066 cm-1 observed upon cooling. These features are probably due to colloidal aluminum hydroxide. The results provide the first evidence for aluminate polymerization at high pressure and temperature, and offer insights into the causes for enhancement of

  4. [Antimicrobial Effects of Iodine-Polyvinyl Alcohol Ophthalmic and Eye Washing Solution (PA * IODO) with Special Reference to its Temperature, Concentration and Time and its Preservation Stability].

    Science.gov (United States)

    Hatano, Hiroshi; Sakamoto, Masako; Hayashi, Kazuo; Kamiya, Seigo

    2015-08-01

    Temperature, concentration and time are the three factors that affect the inactivation capacity of iodine antiseptics. We investigated the effect of these factors on the microbe inactivation of Iodine-Polyvinyl Alcohol ophthalmic and eye washing solution (PA * IODO), and also investigated the preservation conditions on stability of the inactivation activity of the PA * IODO. Test microbes were mixed with PA * IODO, varying the three factors. The live microbes were counted after each reaction. The effects of plugging and preservation temperature were investigated to determine the preserving stability. The inactivation capacity of PA * IODO tended to decrease in almost all microbes tested at 4 degrees C. Twenty times or less diluted PA * IODO killed almost all microbes completely. The time effect was more marked in viruses. Plugging and low-temperature made iodine concentration in diluted PA * IODO remain relatively high. The concentration of PA * IODO affected the inactivation ability more than the temperature and time, although all the three factors correlated positively to the inactivation. For preservation the diluted PA * IODO needed plugging and low temperature.

  5. Densities and apparent molar volumes of aqueous LiI solutions at temperatures from (296 to 600) K and at pressures up to 30 MPa

    International Nuclear Information System (INIS)

    Abdulagatov, I.M.; Azizov, N.D.

    2004-01-01

    Densities of five aqueous LiI solutions (0.0906, 0.2832, 0.6621, 1.6046, and 3.0886) mol . kg -1 H 2 O were measured in the liquid phase with a constant-volume piezometer immersed in a precision liquid thermostat. Measurements were made along various isotherms between (296.95 and 600.25) K. The range of pressure was (0.1 to 30) MPa. The total uncertainty of density, pressure, temperature, and concentration measurements was estimated to be less than 0.06%, 0.05%, 15 mK, and 0.014%, respectively. To check and confirm the accuracy of the measurements, (p,V m ,T,x) data were taken for pure water at selected temperatures and pressures. Experimental and calculated (IAPWS formulation) densities for pure water show excellent agreement within their experimental uncertainties (average absolute deviation is 0.02%). Values of saturated densities were determined by extrapolating experimental p - ρ data to the vapour pressure at fixed temperature and composition using a linear interpolating equation. Apparent molar volumes were derived using measured values of density for solutions and pure water. The apparent molar volumes were extrapolated to zero concentration (m → 0) to yield partial molar volumes of electrolyte (LiI) at infinite dilution. The temperature, pressure, and concentration dependence of apparent and partial molar volumes was studied. The measured values of density, apparent and partial molar volume were compared with data reported in the literature by other authors. A polynomial type of equation of state for specific volume was obtained as a function of temperature, pressure, and composition by a least-squares method using the experimental data. The average absolute deviation (AAD) between measured and calculated values from this polynomial equation for density was 0.065%

  6. Temperature control of functionally graded plates using a feedforward-feedback controller based on the inverse solution and proportional-derivative controller

    International Nuclear Information System (INIS)

    Golbahar Haghighi, M.R.; Eghtesad, M.; Necsulescu, D.S.; Malekzadeh, P.

    2010-01-01

    As a first endeavor, an approach for the two- and three-dimensional temperature control of functionally graded (FG) plates by using the inverse solution and the proportional-differential (PD) controller is provided. For this purpose, firstly, having the desired temperatures at different locations and times, heat fluxes at the boundaries of the plates are estimated by inverse solution techniques offline. Then, the estimated heat fluxes as feedforward control inputs are combined with a PD controller to introduce a hybrid feedforward-feedback control input to the FG domain in the presence of disturbance and noise. In order to show the efficiency and accuracy of the proposed (inverse + PD) controller in two- and three-dimensional domains, different distinct examples, which include different boundary conditions, material properties and disturbance sources are presented. It is shown that the presented approach can adjust heat fluxes for control of the temperature accurately; also, the PD controller gains do not need to be re-adjusted for different problems.

  7. High-pressure densified solid solutions of alkaline earth hexaborides (Ca/Sr, Ca/Ba, Sr/Ba) and their high-temperature thermoelectric properties

    International Nuclear Information System (INIS)

    Gürsoy, M.; Takeda, M.; Albert, B.

    2015-01-01

    Solid solutions of alkaline earth hexaborides were synthesized and densified by spark plasma sintering at 100 MPa. The high-temperature thermoelectric properties (Seebeck coefficients, electrical and thermal diffusivities, heat capacities) were measured between room temperature and 1073 K. CaB 6 , SrB 6 , BaB 6 and the ternary hexaborides Ca x Sr 1−x B 6 , Ca x Ba 1−x B 6 , Sr x Ba 1−x B 6 (x = 0.25, 0.5, 0.75) are n-type conducting compounds over the whole compositional and thermal ranges. The values of the figure of merit ZT for CaB 6 (ca. 0.3 at 1073 K) were found to be significantly increased compared to earlier investigations which is attributed to the densification process. - Highlights: • Solid solutions of alkaline earth hexaborides were synthesized. • High-temperature thermoelectric properties of mixed calcium borides are excellent. • Spark plasma source densification results in high ZT values. • Borides are rare-earth free and refractory materials

  8. Temperature control of functionally graded plates using a feedforward-feedback controller based on the inverse solution and proportional-derivative controller

    Energy Technology Data Exchange (ETDEWEB)

    Golbahar Haghighi, M.R. [Department of Mechanical Engineering, School of Engineering, Persian Gulf University, Bushehr 75168 (Iran, Islamic Republic of); Eghtesad, M. [Department of Mechanical Engineering, School of Engineering, Shiraz University, Shiraz 71348-51154 (Iran, Islamic Republic of); Necsulescu, D.S. [Department of Mechanical Engineering, Faculty of Engineering, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada); Malekzadeh, P., E-mail: malekzadeh@pgu.ac.i [Department of Mechanical Engineering, School of Engineering, Persian Gulf University, Bushehr 75168 (Iran, Islamic Republic of); Center of Excellence for Computational Mechanics, Shiraz University, Shiraz (Iran, Islamic Republic of)

    2010-01-15

    As a first endeavor, an approach for the two- and three-dimensional temperature control of functionally graded (FG) plates by using the inverse solution and the proportional-differential (PD) controller is provided. For this purpose, firstly, having the desired temperatures at different locations and times, heat fluxes at the boundaries of the plates are estimated by inverse solution techniques offline. Then, the estimated heat fluxes as feedforward control inputs are combined with a PD controller to introduce a hybrid feedforward-feedback control input to the FG domain in the presence of disturbance and noise. In order to show the efficiency and accuracy of the proposed (inverse + PD) controller in two- and three-dimensional domains, different distinct examples, which include different boundary conditions, material properties and disturbance sources are presented. It is shown that the presented approach can adjust heat fluxes for control of the temperature accurately; also, the PD controller gains do not need to be re-adjusted for different problems.

  9. Impact of Initial pH and Pyrolysis Temperature on the Adsorption of Cr(Ⅵ from Aqueous Solutions on Corn Straw-based Materials

    Directory of Open Access Journals (Sweden)

    WANG Shuai

    2016-09-01

    Full Text Available Batch experiments were performed on Cr(Ⅵ adsorption using four straw-based materials including corn straw and three kinds of biochar pyrolysed at 300 ℃, 450 ℃ and 600 ℃, respectively. The results showed that the Cr(Ⅵ adsorption were significantly affected by initial pH and pyrolysis temperature. The data were described by kinetic and isotherm models, and showed that the adsorption of Cr(Ⅵ was increased with the decrease of initial pH. The removal rates of Cr(Ⅵ were decreased with the increase of the pyrolysis temperature at pH=3 or pH=5. The biochar pyrolysed at 300 ℃ had the best capability of removing Cr(Ⅵ from aqueous solution at pH=1, and the maxi-mum adsorption quantity was 141.24 mg·g-1 approximately. It observed that both the lower initial pH and the lower pyrolysis temperature had positive effects on the removal of Cr(Ⅵ from aqueous solution.

  10. High-temperature electrical properties of the Bi2.1Sr1.9(Ca1-xYx)Cu2Oy solid solution

    International Nuclear Information System (INIS)

    Hong, Byungsun; Mason, T.O.

    1993-01-01

    By a combination of conventional physical property measurements and high temperature electrical property studies, the solid solution limit, transport parameters, and potential defect regimes of the Bi 2.1 Sr 1.9 (Ca 1 - x Y x )Cu 2 O y solid solution were established. A continuous solid solution extends to x = 0.7 or 0.8. The electrical properties indicate that the product of the hole density-of-states and mobility for semiconducting compositions is approximately an order of magnitude smaller than for the other p-type superconducting cuprates. A pronounced drop in hole concentration accompanies the tetragonal-to-orthorhombic transition at x = 0.5, where after superconductivity disappears. The electrical properties also indicate that a composition x ≥ 0.7 is the appropriate ''reference'' compound for the solid solution series. Upon doping this yttrium-rich insulating composition with calcium, holes are introduced. With increased calcium content (decreased yttrium content) the system exhibits several defect regimes reminiscent of the behavior in the La 2 - x AE x CuO 4 (AE = Sr or Ba) system. Oxygen defects (interstitial and vacancies) are believed to play an important role in the defect structure

  11. Dielectric spectroscopy in aqueous solutions of paracetamol over the frequency range of 20 Hz to 2 MHz at 293.15 K temperature

    Science.gov (United States)

    Pandit, T. R.; Rana, V. A.

    2018-05-01

    Frequency domain dielectric relaxation spectroscopy plays an important role in the study of pharmaceutical drug molecules. The complex relative dielectric permittivity ɛ*(ω) = ɛ' - j ɛ" of aqueous solutions of paracetamol in the frequency range of 20 Hz to 2 MHz at a temperature range of 293.15 K are measured with the help of Agilent precision LCR meter E4980A along with four terminal liquid test fixture Agilent 16452A. Data of complex relative permittivity are used to calculate loss tangent for all concentrations of paracetamol in distilled water. Electrode polarization relaxation time has been calculated for all solutions. Effect of variation of concentrations of paracetamol in distilled water on these dielectric parameters is discussed.

  12. Investigation of six-membered carbocyclic compounds as a molecular switch block of room temperature phosphorescence in nondeoxygenated {beta}-cyclodextrin solution

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Hairong; Wei Yansheng; Jin Weijun; Liu Changsong

    2003-05-07

    An aerated aqueous solution, intense room temperature phosphorescence (RTP) of nitrogen heterocyclic compounds (NHCs) and polyaromatic hydrocarbons (PAHs) can be observed when micro amounts of six-membered carbocyclic compounds (6-MCCs) are introduced in {beta}-cyclodextrin ({beta}-CD) solution. In order to find the predominating factors of the enhanced phosphorescence observed with this novel approach, 22 typical phosphors of NHCs and PAHs were carefully screened and served as model compounds. The role of the inner heavy atom, the substituent group and the host-guest molecules space-matching on the RTP of different phosphors were investigated. The results demonstrated that the enhancement effects of cyclohexane, bromocyclohexane and cyclohexanol for the RTP of NHCs and PAHs have precedence over traditional halide alkanes such as 1,2-dibromoethane (DBE), exhibiting an obvious sequence as following: cyclohexane > bromocyclohexane > cyclohexanol. This new approach compared with other RTP methods is simple, convenient and fast.

  13. Investigation of six-membered carbocyclic compounds as a molecular switch block of room temperature phosphorescence in nondeoxygenated β-cyclodextrin solution

    International Nuclear Information System (INIS)

    Zhang Hairong; Wei Yansheng; Jin Weijun; Liu Changsong

    2003-01-01

    An aerated aqueous solution, intense room temperature phosphorescence (RTP) of nitrogen heterocyclic compounds (NHCs) and polyaromatic hydrocarbons (PAHs) can be observed when micro amounts of six-membered carbocyclic compounds (6-MCCs) are introduced in β-cyclodextrin (β-CD) solution. In order to find the predominating factors of the enhanced phosphorescence observed with this novel approach, 22 typical phosphors of NHCs and PAHs were carefully screened and served as model compounds. The role of the inner heavy atom, the substituent group and the host-guest molecules space-matching on the RTP of different phosphors were investigated. The results demonstrated that the enhancement effects of cyclohexane, bromocyclohexane and cyclohexanol for the RTP of NHCs and PAHs have precedence over traditional halide alkanes such as 1,2-dibromoethane (DBE), exhibiting an obvious sequence as following: cyclohexane > bromocyclohexane > cyclohexanol. This new approach compared with other RTP methods is simple, convenient and fast

  14. Lowering of the critical concentration for micelle formation in aqueous soap solutions by action of truly dissolved hydrocarbon at various temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Markina, Z.N.; Kostova, N.Z.; Rebinder, P.A.

    1970-03-01

    The effect of dissolved hydrocarbons (octane, benzene, and ethylbenzene) on critical micelle concentration of aqueous solutions of sodium salts of fatty acids from caproate to sodium myristate at various temperatures was studied. Experimental results showed that formation of micelles is promoted by presence of hydrocarbons dissolved in the water phase. Such solutions have below normal critical micelle concentration. The change in critical micelle concentration decreases with increase in length of hydrocarbon chain in the soap molecule and with decrease of hydrocarbon solubility in pure water. The nature of the hydrocarbon also affects the forms and dimension of the micelle. Aromatic hydrocarbons increase micelle volume and greatly decrease C.M.C., while aliphatic hydrocarbons decrease C.M.C. slightly. (12 refs.)

  15. P25-graphene hydrogels: room-temperature synthesis and application for removal of methylene blue from aqueous solution.

    Science.gov (United States)

    Hou, Chengyi; Zhang, Qinghong; Li, Yaogang; Wang, Hongzhi

    2012-02-29

    Herein we report a room-temperature synthesis of chemically bonded TiO2 (P25)-graphene composite hydrogels and their use as high performance visible light photocatalysts. The three-dimensional (3D) TiO2-carbon composite exhibits a significant enhancement in the reaction rate in the decontamination of methylene blue, compared to the bare P25. The 3D P25-graphene hydrogel is much easier to prepare and apply as a macroscopic device, compared to the 2D P25-graphene sheets. This work could provide new insights into the room-temperature synthesis of graphene-based materials. As a kind of the novel 3D graphene-based composite, the obtained high performance P25-graphene gel could be widely used in the environmental protection issues. Copyright © 2012. Published by Elsevier B.V.

  16. Many-electron electrochemical processes. Reactions in molten salts, room-temperature ionic liquids and ionic solutions

    Energy Technology Data Exchange (ETDEWEB)

    Andriiko, Aleksandr A. [National Technical Univ. Ukraine, Kyiv (Ukraine). Kyiv Polytechnic Inst.; Andriyko, Yuriy O. [CEST Centre of Electrochemical Surface Technology, Wiener Neustadt (Austria); Nauer, Gerhard E. [Vienna Univ. (Austria). Inst. of Physical Chemistry

    2013-02-01

    The authors provide a unified concept for understanding multi-electron processes in electrochemical systems such as molten salts, ionic liquids, or ionic solutions. A major advantage of this concept is its independence of assumptions like one-step many-electron transfers or 'discrete' discharge of complex species. This book contains the following main topics: 1. Many-electron electrochemical systems: Concepts and definitions. 2. Many-electron systems at equilibrium. 3. Phenomenology of electrochemical kinetics. 4. Electrode film systems: experimental evidences. 5. Dynamics of a non-equilibrium electrochemical system. 6. Electrochemistry of Ti(IV) in ionic liquids.

  17. High temperature effect on microflora of radish root-inhabited zone and nutrient solutions for radish growth

    Science.gov (United States)

    Borodina, E. V.; Tirranen, L. S.

    The effect of high temperatures (35 and 45 °C) on microflora of the root zone of radish plants grown in phytotron was evaluated by the response of microorganisms from 9 indicator groups. Phytotron air temperature elevated to 35 °C for 20 hours caused no significant changes in qualitative and quantitative composition of the root microflora in experimental plants. By the end of the experiment, the species diversity of microflora had changed. The amount of phytopathogenic microorganisms decreased which can be interpreted as more stable co-existence of microflora with plants. The numbers of microbes from other indicator groups was in dynamic equilibrium. The plants' condition did not deteriorate either. Exposure to the temperature of 45 °C for 7 hours have been found to change the numbers and species diversity in the radish root zone microflora. The microorganisms were observed to increase their total numbers at the expense of certain indicator groups. Bacteria increased spore forms at the stage of spores. Colon bacillus bacteria of increased their numbers by the end of experiment by an order. By the end of experiment the roots of experiment plants had microscopic fungi from Mucor, Aspergillus, Trichoderma, Cladosporium genera. The observed changes in the microbial complex seem to be associated with the changes of root emissions and general deterioration of the plants' condition. It is suggested that the response of the microorganisms can be indicative of the condition of plants under investigation.

  18. Effect of temperature and heat fluxes on the corrosion's damage nature for mild and stainless steels in neutral chloride solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kaluzhina, S.A. [Voronezh State University, University Sq.1, 394006 Voronezh (Russian Federation); Malygin, A.V. [JSC Voronezhsynthezkauchuk, Leninsky Av. 2, 394014 Voronezh (Russian Federation); Vigdorovitch, V.V. [Derzhavin State University, International St. 33, 392622 Tambov (Russian Federation)

    2004-07-01

    The detail research of the corrosion-electrochemical behavior of two types steels - mild steel (0.1%C) and stainless steel 12FeCr18Ni10Ti in series chloride solutions under elevated temperature and heat flux on interface has been carried out in the present work using the special plant and the complex electrochemical and microscopic methods. The comparative data has shown that the temperature increase is stimulating as the active alloy's corrosion (mild steel), so the passive alloy's corrosion (12FeCr18Ni10Ti).However at the last case the temperature effect is being higher because the thermal de-passivation of the stainless steel which undergoes pit corrosion under t > 50 deg C. The heat-transfer role in the studied systems is ambiguous. The corrosion rate of heat-transferring electrode from mild steel exceeds the thermo-equilibrium with solution electrode's corrosion rate because of intensification of the oxygen reduction cathodic process. The opposite effect has been established for steel 12FeCr18Ni10Ti where the oxygen flux's strengthening from cold solution to the heated surface transfers the alloy to the most stable passive state and increases its resistance to general and local corrosion. The experimental results demonstrates that the thermal condition's influence on the nature and corrosion intensity of the investigated steels is being commensurable by effect's degree with their composition and showing strictly individually. (authors)

  19. Low-temperature, solution-processed aluminum-doped zinc oxide as electron transport layer for stable efficient polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Qianqian [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Bao, Xichang, E-mail: baoxc@qibebt.ac.cn [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Yu, Jianhua [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Zhu, Dangqiang [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Zhang, Qian [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Gu, Chuantao [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Dong, Hongzhou [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Yang, Renqiang [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Dong, Lifeng, E-mail: DongLifeng@qust.edu.cn [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Department of Physics, Hamline University, St. Paul, MN 55104 (United States)

    2016-04-30

    A simple low-temperature solution-processed zinc oxide (ZnO) and aluminum-doped ZnO (AZO) were synthesized and investigated as an electron transport layer (ETL) for inverted polymer solar cells. A solar cell with a blend of poly(4,8-bis-alkyloxy-benzo[1,2-b:4,5-b′] dithiophene-alt-alkylcarbonyl-thieno [3,4-b] thiophene) and (6,6)-phenyl-C71-butyric acid methyl ester as an active layer and AZO as ETL demonstrates a high power conversion efficiency (PCE) of 7.36% under the illumination of AM 1.5G, 100 mW/cm{sup 2}. Compared to the cells with ZnO ETL (PCE of 6.85%), the PCE is improved by 7.45% with the introduction of an AZO layer. The improved PCE is ascribed to the enhanced short circuit current density, which results from the electron transport property of the AZO layer. Moreover, AZO is a more stable interfacial layer than ZnO. The PCE of the solar cells with AZO as ETL retain 85% of their original value after storage for 120 days, superior to the 39% of cells with ZnO ETL. The results above indicate that a simple low-temperature solution-processed AZO film is an efficient and economical ETL for high-performance inverted polymer solar cells. Due to its environmental friendliness, good electrical properties, and simple preparation approach, AZO has the potential to be applied in high-performance, large-scale industrialization of solar cells and other electronic devices. - Highlights: • ZnO and AZO were synthesized by a simple low-temperature solution-processed method. • AZO films show high transmittance and conductivity. • The photovoltaic performance can be improved with AZO as ETL. • AZO-based devices demonstrate excellent stability, with 85% retained after 120 days.

  20. Partial molar volumes and partial molar adiabatic compressibilities of a short chain perfluorosurfactant: Sodium heptafluorobutyrate in aqueous solutions at different temperatures

    International Nuclear Information System (INIS)

    Blanco, Elena; Ruso, Juan M.; Prieto, Gerardo; Sarmiento, Felix

    2005-01-01

    Density and ultrasound measurements of sodium heptafluorobutyrate in aqueous solutions at T = (283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K have been obtained. From these results partial molar volumes and isentropic partial molar adiabatic compressibilities were calculated. Deviations from the Debye-Hueckel limiting law provide evidence for limited association at lower concentrations. The change of the partial molar volume and isentropic partial molar adiabatic compressibility upon aggregation was calculated. Variations of the change of partial molar volumes and isentropic partial molar adiabatic compressibility upon aggregation are discussed in terms of temperature

  1. Partial molar volumes and partial molar adiabatic compressibilities of a short chain perfluorosurfactant: Sodium heptafluorobutyrate in aqueous solutions at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Blanco, Elena [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Ruso, Juan M. [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)]. E-mail: faruso@usc.es; Prieto, Gerardo [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Sarmiento, Felix [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)

    2005-12-15

    Density and ultrasound measurements of sodium heptafluorobutyrate in aqueous solutions at T = (283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K have been obtained. From these results partial molar volumes and isentropic partial molar adiabatic compressibilities were calculated. Deviations from the Debye-Hueckel limiting law provide evidence for limited association at lower concentrations. The change of the partial molar volume and isentropic partial molar adiabatic compressibility upon aggregation was calculated. Variations of the change of partial molar volumes and isentropic partial molar adiabatic compressibility upon aggregation are discussed in terms of temperature.

  2. Hole-transporting transistors and circuits based on the transparent inorganic semiconductor copper(I) thiocyanate (CuSCN) processed from solution at room temperature

    KAUST Repository

    Pattanasattayavong, Pichaya

    2012-12-27

    The wide bandgap and highly transparent inorganic compound copper(I) thiocyanate (CuSCN) is used for the first time to fabricate p-type thin-film transistors processed from solution at room temperature. By combining CuSCN with the high-k relaxor ferroelectric polymeric dielectric P(VDF-TrFE-CFE), we demonstrate low-voltage transistors with hole mobilities on the order of 0.1 cm2 V-1 s-1. By integrating two CuSCN transistors, unipolar logic NOT gates are also demonstrated. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Fast and low-temperature sintering of silver complex using oximes as a potential reducing agent for solution-processible, highly conductive electrodes

    International Nuclear Information System (INIS)

    Yoo, Ji Hoon; Park, Su Bin; Kim, Ji Man; Han, Dae Sang; Chae, Jangwoo; Kwak, Jeonghun

    2014-01-01

    Highly conductive, solution-processed silver thin-films were obtained at a low sintering temperature of 100 °C in a short sintering time of 10 min by introducing oximes as a potential reductant for silver complex. The thermal properties and reducibility of three kinds of oximes, acetone oxime, 2-butanone oxime, and one dimethylglyoxime, were investigated as a reducing agent, and we found that the thermal decomposition product of oximes (ketones) accelerated the conversion of silver complex into highly conductive silver at low sintering temperature in a short time. Using the acetone oxime, the silver thin-film exhibited the lowest surface resistance (0.91 Ω sq −1 ) compared to those sing other oximes. The silver thin-film also showed a high reflectance of 97.8%, which is comparable to evaporated silver films. We also demonstrated inkjet printed silver patterns with the oxime-added silver complex inks. (paper)

  4. Effect of Annealing Temperature on the Corrosion Protection of Hot Swaged Ti-54M Alloy in 2 M HCl Pickling Solutions

    Directory of Open Access Journals (Sweden)

    El-Sayed M. Sherif

    2017-01-01

    Full Text Available The corrosion of Ti-54M titanium alloy processed by hot rotary swaging and post-annealed to yield different grain sizes, in 2 M HCl solutions is reported. Two annealing temperatures of 800 °C and 940 °C, followed by air cooling and furnace cooling were used to give homogeneous grain structures of 1.5 and 5 μm, respectively. It has been found that annealing the alloy at 800 °C decreased the corrosion of the alloy, with respect to the hot swaged condition, through increasing its corrosion resistance and decreasing the corrosion current and corrosion rate. Increasing the annealing temperature to 940 °C further decreased the corrosion of the alloy.

  5. Precipitation in solid solution and structural transformations in single crystals of high rhenium ruthenium-containing nickel superalloys at high-temperature creep

    Energy Technology Data Exchange (ETDEWEB)

    Alekseev, A.A.; Petrushin, N.V.; Zaitsev, D.V.; Treninkov, I.A.; Filonova, E.V. [All-Russian Scientific Research Institute of Aviation Materials (VIAM), Moscow (Russian Federation)

    2010-07-01

    The phase composition and structure of single crystals of two superalloys (alloy 1 and alloy 2) were investigated in this work. For alloy 1 (Re - 9 wt%) the kinetics of precipitation in solid solution at heat treatment (HT) was investigated. TEM and X-Ray examinations have revealed that during HT rhombic phase (R-phase) precipitation (Immm class (BCR)) occurs. The TTT diagram is plotted, it contains the time-temperature area of the existence of R-phase particles. The element content of R-phase is identified (at. %): Re- 51.5; Co- 23.5; Cr- 14.8; Mo- 4.2; W- 3.3; Ta- 2.7. For alloy 2 (Re - 6.5 wt %, Ru - 4 wt %) structural transformations at high-temperature creep are investigated. By dark-field TEM methods it is established, that in alloy 2 the additional phase with a rhombic lattice is formed during creep. Particles of this phase precipitate in {gamma}-phase and their quantity increases during high-temperature creep. It is revealed that during creep 3-D dislocation network is formed in {gamma}-phase. At the third stage of creep the process of inversion structure formation is observed in the alloy, i.e. {gamma}'-phase becomes a matrix. Thus during modeling creep the volume fraction of {gamma}'-phase in the samples increases from 30% (at creep duration of 200 hrs) up to 55% (at 500 hrs). The processes of structure formation in Re and Ru-containing nickel superalloys are strongly affected by decomposition of solid solution during high-temperature creep that includes precipitation of additional TCP-phases. (orig.)

  6. Degradation kinetics of fisetin and quercetin in solutions affected by medium pH, temperature and co-existed proteins

    Directory of Open Access Journals (Sweden)

    Wang Jing

    2016-01-01

    Full Text Available Impacts of medium pH, temperature and coexisted proteins on the degradation of two flavonoids fisetin and quercetin were assessed by spectroscopic method in the present study. Based on the measured degradation rate constants (k, fisetin was more stable than quercetin in all cases. Increasing medium pH from 6.0 to 7.5 at 37°C enhanced respective k values of fisetin and quercetin from 8.30x10−3 and 2.81x10−2 to 0.202 and 0.375 h-1 (P<0.05. In comparison with their degradation at 37°C, fisetin and quercetin showed larger k values at higher temperature (0.124 and 0.245 h−1 at 50°C, or 0.490 and 1.42 h−1 at 65°C. Four protein products in medium could stabilize the two flavonoids (P<0.05, as these proteins at 0.10 g L-1 decreased respective k values of fisetin and quercetin to 2.28x10−2-2.98x10−2 and 4.37´10−2-5.97x10−2 h−1. Hydrophobic interaction between the proteins and the two flavonoids was evidenced responsible for the stabilization, as sodium dodecyl sulfate could destroy the stabilization significantly (P<0.05. Casein and soybean protein provided greater stabilization than whey protein isolate. It is thus concluded that higher temperature and alkaline pH can enhance flavonoid loss, whereas coexisted proteins as flavonoid stabilizers can inhibit flavonoid degradation.

  7. Reduced water vapor transmission rates of low-temperature solution-processed metal oxide barrier films via ultraviolet annealing

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seonuk; Jeong, Yong Jin; Baek, Yonghwa; Kim, Lae Ho; Jang, Jin Hyuk; Kim, Yebyeol [POSTECH Organic Electronics Laboratory, Polymer Research Institute, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); An, Tae Kyu [Department of Polymer Science & Engineering, Korea National University of Transportation, 50 Daehak-Ro, Chungju (Korea, Republic of); Nam, Sooji, E-mail: sjnam15@etri.re.kr [Information Control Device Section, Electronics and Telecommunications Research Institute, Daejeon, 305-700 (Korea, Republic of); Kim, Se Hyun, E-mail: shkim97@yu.ac.kr [School of Chemical Engineering, Yeungnam University, Gyeongsan, North Gyeongsang 712-749 (Korea, Republic of); Jang, Jaeyoung, E-mail: jyjang15@hanyang.ac.kr [Department of Energy Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Park, Chan Eon, E-mail: cep@postech.ac.kr [POSTECH Organic Electronics Laboratory, Polymer Research Institute, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of)

    2017-08-31

    Highlights: • Sol-gel-derived aluminum oxide thin films were prepared using ultraviolet (UV) annealing. • UV irradiation dramatically promoted the densification of AlO{sub x} during the annealing stage, thereby forming a close-packed AlO{sub x} film. • The resulting AlO{sub x} films deposited on polymer substrates exhibited good water vapor blocking properties with low water vapor transmission rates (WVTRs). - Abstract: Here, we report the fabrication of low-temperature sol-gel-derived aluminum oxide (AlO{sub x}) films via ultraviolet (UV) annealing and the investigation of their water vapor blocking properties by measuring the water vapor transmission rates (WVTRs). The UV annealing process induced the formation of a dense metal-oxygen-metal bond (Al-O-Al structure) at low temperatures (<200 °C) that are compatible with commercial plastic substrates. The density of the UV-annealed AlO{sub x} thin film at 180 °C was comparable to that of AlO{sub x} thin films that have been thermally annealed at 350 °C. Furthermore, the UV-annealed AlO{sub x} thin films exhibited a high optical transparency in the visible region (>99%) and good electrical insulating properties (∼10{sup −7} A/cm{sup 2} at 2 MV/cm). Finally, we confirmed that a dense AlO{sub x} thin film was successfully deposited onto the plastic substrate via UV annealing at low temperatures, leading to a substantial reduction in the WVTRs. The Ca corrosion test was used to measure the WVTRs of AlO{sub x} thin films deposited onto polyethylene naphthalate or polyimide substrates, determined to be 0.0095 g m{sup −2} day{sup −1} (25 °C, 50% relative humidity) and 0.26 g m{sup −2} day{sup −1}, respectively.

  8. Shape- and size-controlled synthesis of nanometre ZnO from a simple solution route at room temperature

    International Nuclear Information System (INIS)

    Cao, H L; Qian, X F; Gong, Q; Du, W M; Ma, X D; Zhu, Z K

    2006-01-01

    Single crystalline ZnO nanorods with a diameter of about 5 nm were synthesized without the presence of any surfactants in ethanol solvent at room temperature. Nanodots and nanorods with different size and shape could be observed by TEM via simply altering NaOH concentration and reaction time. The polar ZnO nanorod growth mechanism was discussed by the 'Ostwald ripening' mechanism. Optical absorption and photoluminescence properties of ZnO nanorods have been characterized. The UV absorption spectrum revealed a clear blue-shift with a single absorption peak centred at 350 nm

  9. Rare-earth elements and uranium in high-temperature solutions from East Pacific Rise hydrothermal vent field (130N)

    International Nuclear Information System (INIS)

    Michard, A.; Albarede, F.; Michard, G.; Minster, J.F.; Charlou, J.L.

    1983-01-01

    The mobility of rare-earth elements (REE) and U during hydrothermal alteration of the basalts at spreading centres has long been a matter of concern because of its bearing on the evolution and recycling of the oceanic crust. Previous approaches to this problem have been indirect, through studies on altered dredged basalts or ophiolites. Sampling of hydrothermal vent waters from the East Pacific Rise (EPR) at 13 0 N is reported. It provides the first direct evidence of REE-enriched solutions which, however, leave the budget of these elements in the crust and the ocean rather unmodified. In constrast, uranium, like magnesium, is quantitatively taken up from the seawater during the hydrothermal process. (author)

  10. Annealing effects on the optical and morphological properties of ZnO nanorods on AZO substrate by using aqueous solution method at low temperature.

    Science.gov (United States)

    Hang, Da-Ren; Islam, Sk Emdadul; Sharma, Krishna Hari; Kuo, Shiao-Wei; Zhang, Cheng-Zu; Wang, Jun-Jie

    2014-01-01

    Vertically aligned ZnO nanorods (NRs) on aluminum-doped zinc oxide (AZO) substrates were fabricated by a single-step aqueous solution method at low temperature. In order to optimize optical quality, the effects of annealing on optical and structural properties were investigated by scanning electron microscopy, X-ray diffraction, photoluminescence (PL), and Raman spectroscopy. We found that the annealing temperature strongly affects both the near-band-edge (NBE) and visible (defect-related) emissions. The best characteristics have been obtained by employing annealing at 400°C in air for 2 h, bringing about a sharp and intense NBE emission. The defect-related recombinations were also suppressed effectively. However, the enhancement decreases with higher annealing temperature and prolonged annealing. PL study indicates that the NBE emission is dominated by radiative recombination associated with hydrogen donors. Thus, the enhancement of NBE is due to the activation of radiative recombinations associated with hydrogen donors. On the other hand, the reduction of visible emission is mainly attributed to the annihilation of OH groups. Our results provide insight to comprehend annealing effects and an effective way to improve optical properties of low-temperature-grown ZnO NRs for future facile device applications.

  11. Effect of Cacl2 Solution at Different Temperatures on Qualitative and Quantitative Characteristics and Shelf Life of Peach Fruit, Cv. Anjiri Maliki

    Directory of Open Access Journals (Sweden)

    F. Karamnejad

    2014-04-01

    Full Text Available In order to study the effect of CaCl2 treatment on postharvest quality and storage behavior of peach fruit cv. Anjiri Maliki, the fruits were dipped in CaCl2 solution, at concentration of 0 as control and 60mM, in different temperatures (4, 8, 16, 32 and 64°C for 5 minutes. The trial was carried out as a factorial experiment if frame of complete randomized design (CRD with three replications. The fruits were stored at 2-3°C and 85-90% R.H for finally 28 days, and then the fruit parameters were measured weekly. Traits such as titratable acidity (TA, total soluble solids (TSS, vitamin C, weight loss, tissue firmness and calcium concentration were determined. Results showed that in total storage period (four measurements times, treatment with CaCl2, at temperature of 64°C was the best treatment according to maintaining flesh firmness, maintaining TSS, preventing the degradation of ascorbic acid, reducing the TA changes, modulation of weight loss and increasing the amount of calcium content in fruits. Also thermal treatments at temperatures of 32 and 64°C, alone end without CaCl2, had significant effects on maintaining fruit firmness, TA and acid ascorbic and caused to modulation in weight loss. On the other hand the application of calcium chloride at temperatures of 4 and 32°C had significant effect on quality parameters.

  12. Molecular dynamics study on the structural and dynamic properties of xanthan gum in a dilute solution under the effect of temperature

    Science.gov (United States)

    Ong, Ernest E. S.; O'Byrne, Sean; Liow, Jong-Leng

    2018-04-01

    Xanthan gum (XG) is considered one of the most industrially important polysaccharides, with applications ranging from food products such as ice creams and salad dressings to pharmaceuticals and oil well drilling fluids. The wide application of XG is due to its favourable rheological properties and its capability to resist degradation under a high shear or high temperature environment. It is generally accepted that both inter- and intramolecular interactions, including hydrogen bonding (HB), are responsible for its unique properties. To date, there is still a lack of comprehensive examination on the HB mechanism in polysaccharides. Therefore, the study proposed here was conducted using molecular dynamics (MD) simulations that are able to provide insights with an unparalleled temporal and spatial resolution. Since XG is used over a broad range of temperatures, the implications of thermal effect on the structure and molecular interactions of XG in an aqueous solution are discussed in this paper. MD simulations were run at an isobaric-isothermal condition with 1 atm target pressure and five temperatures ranging between 283K and 353K. From the simulation results, an increasingly extended conformation of XG is observed as the temperature rises, and this finding matches qualitatively with the results published in the literature. The radius of gyration, radial pair distribution functions and intramolecular HB of XG were also discussed. The outcomes of the present study may serve as a stepping stone for the future studies on polysaccharides using MD simulations.

  13. Determination of the optical properties of PNIPAAm gels used in biological applications

    CSIR Research Space (South Africa)

    Singh, A

    2009-07-01

    Full Text Available Poly(N-isopropylacrylamide) that is PNIPAAm is a temperature sensitive smart material which displays a lower critical solution temperature (LCST) at 33-35oC. At the lower critical solution temperature, the gel changes from hydrophilic to hydrophobic...

  14. Cathodic electrochemical deposition of Magnéli phases TinO2n−1 thin films at different temperatures in acetonitrile solution

    International Nuclear Information System (INIS)

    Ertekin, Zeliha; Tamer, Uğur; Pekmez, Kadir

    2015-01-01

    Highlights: • TiO x films were prepared by cathodic electrodeposition in acetonitrile. • One-step electrodeposition of TiO x films without heat treatment process. • Different crystalline Ti n O 2n−1 films (γTi 3 O 5 , λTi 3 O 5 , Ti 4 O 7 , Ti 5 O 9 ) were obtained. - Abstract: The Magnéli phase titanium oxide films prepared by cathodic electrodeposition on indium–tin-oxide coated glass substrates from saturated peroxo-titanium solution in acetonitrile. Electrodeposited brownish semi-conductor thin films were identified via X-ray diffraction, Raman spectroscopy, UV–vis spectroscopy and scanning electron microscopy (SEM). The effects of different potentials and temperatures on the crystallinity of the thin films have been discussed. Ti 3 O 5 , Ti 4 O 7 and Ti 5 O 9 as the most favorable forms of the Ti n O 2n−1 were electrodeposited on ITO electrode at electrochemical deposition potentials and different temperatures. The present investigation reveals that the electrochemical deposition of crystalline Ti n O 2n−1 films by a simple one-step electrodeposition method (without any heat treatment) in acetonitrile solution is possible and very promising as a preparation method for electrochemical applications

  15. Partial molar volumes of organic solutes in water. XXVIII. Three aliphatic poly(ethylene glycols) at temperatures T = 298 K–573 K and pressures up to 30 MPa

    International Nuclear Information System (INIS)

    Cibulka, Ivan

    2017-01-01

    Highlights: • Standard molar volumes of three poly(ethylene glycols) in water are presented. • Data were obtained in the range T from (298 to 573) K and p up to 30 MPa. • Data are analyzed and compared with those of similar solutes. - Abstract: Densities of dilute aqueous solutions of three poly(ethylene glycols): 3-oxapentane-1,5-diol (diethylene glycol), 3,6-dioxaoctane-1,8-diol (triethylene glycol), and 3,5,9-trioxaundecane-1,11-diol (tetraethylene glycol) measured in the temperature range from (298 to 573) K and at pressures up to 30 MPa using an automated flow vibrating-tube densimeter are reported. Standard molar volumes were evaluated from the measured data. Present data complement both the previous measurements performed at atmospheric pressure in the temperature range from (278 to 343) K and the data already available for the first member of the homologous series (ethylene glycol). A comparison with data previously measured for the homologous series of linear aliphatic polyethers (poly(ethylene glycol) dimethyl ethers, glymes), diethylene glycol monomethyl ether (3,6-dioxaheptan-1-ol), and selected alkane-α,ω-diols is presented.

  16. Room-Temperature and Solution-Processable Cu-Doped Nickel Oxide Nanoparticles for Efficient Hole-Transport Layers of Flexible Large-Area Perovskite Solar Cells.

    Science.gov (United States)

    He, Qiqi; Yao, Kai; Wang, Xiaofeng; Xia, Xuefeng; Leng, Shifeng; Li, Fan

    2017-12-06

    Flexible perovskite solar cells (PSCs) using plastic substrates have become one of the most attractive points in the field of thin-film solar cells. Low-temperature and solution-processable nanoparticles (NPs) enable the fabrication of semiconductor thin films in a simple and low-cost approach to function as charge-selective layers in flexible PSCs. Here, we synthesized phase-pure p-type Cu-doped NiO x NPs with good electrical properties, which can be processed to smooth, pinhole-free, and efficient hole transport layers (HTLs) with large-area uniformity over a wide range of film thickness using a room-temperature solution-processing technique. Such a high-quality inorganic HTL allows for the fabrication of flexible PSCs with an active area >1 cm 2 , which have a power conversion efficiency over 15.01% without hysteresis. Moreover, the Cu/NiO x NP-based flexible devices also demonstrate excellent air stability and mechanical stability compared to their counterpart fabricated on the pristine NiO x films. This work will contribute to the evolution of upscaling flexible PSCs with a simple fabrication process and high device performances.

  17. Low-temperature magnetic susceptibility of the solid solutions (ErxY1-x)3Al5O12

    International Nuclear Information System (INIS)

    Bagdasarov, Kh.S.; Dodokin, A.P.; Sorokin, A.A.

    1988-01-01

    Measurements of magnetic susceptibility of erbium-yttrium alumogarnets in the 0.04-4.2 K temperature range are carried out. (Er x I 1-x ) 3 Al 5 O 12 monocrystals were grown by the method of vertical directed crystallization. The specimens were produced as 5 cm high cylinders 0.63 cm in diameter; the axis of the cylinders coincided with the (100) direction of the crystals. Magnetic susceptibility was measured by the Harsthorn bridge method at the frequency of 33 Hz. The analysis of measurement results shows that susceptibility of the investigated crystals at T >or approx. 2T N is well described by the Curie-Weiss law. Existence of threshold concentration of the magnetic component testifies to an essential role of exchange interactions in establishment of the magnetic order in Er 3 Al 5 O 12

  18. Reactive Spark Plasma Sintering and Mechanical Properties of Zirconium Diboride–Titanium Diboride Ultrahigh Temperature Ceramic Solid Solutions

    Directory of Open Access Journals (Sweden)

    Karthiselva N. S.

    2016-09-01

    Full Text Available Ultrahigh temperature ceramics (UHTCs such as diborides of zirconium, hafnium tantalum and their composites are considered to be the candidate materials for thermal protection systems of hypersonic vehicles due to their exceptional combination of physical, chemical and mechanical properties. A composite of ZrB2-TiB2 is expected to have better properties. In this study, an attempt has been made to fabricate ZrB2-TiB2 ceramics using mechanically activated elemental powders followed by reactive spark plasma sintering (RSPS at 1400 °C. Microstructure and phase analysis was carried out using X-ray diffractometer (XRD and electron microscopy to understand microstructure evolution. Fracture toughness and hardness were evaluated using indentation methods. Nanoindentation was used to measure elastic modulus. Compressive strength of the composites has been reported.

  19. Liquid-liquid miscibility and volumetric properties of aqueous solutions of ionic liquids as a function of temperature

    International Nuclear Information System (INIS)

    Wang Silu; Jacquemin, Johan; Husson, Pascale; Hardacre, Christopher; Costa Gomes, Margarida F.

    2009-01-01

    The volumetric properties of seven {water + ionic liquid} binary mixtures have been studied as a function of temperature from (293 to 343) K. The phase behaviour of the systems was first investigated using a nephelometric method and excess molar volumes were calculated from densities measured using an Anton Paar densimeter and fitted using a Redlich-Kister type equation. Two ionic liquids fully miscible with water (1-butyl-3-methylimidazolium tetrafluoroborate ([C 1 C 4 Im][BF 4 ]) and 1-ethyl-3-methylimidazolium ethylsulfate ([C 1 C 2 Im][EtSO 4 ])) and five ionic liquids only partially miscible with water (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C 1 C 2 Im][NTf 2 ]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C 1 C 4 Im][NTf 2 ]), 1-butyl-3-methylimidazolium hexafluorophosphate ([C 1 C 4 Im][PF 6 ]), 1-butyl-3-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C 1 C 4 Pyrro][NTf 2 ]), and butyltrimethylammonium bis(trifluoromethylsulfonyl)imide ([N 4111 ][NTf 2 ])) were chosen. Small excess volumes (less than 0.5 cm 3 . mol -1 at 298 K) are obtained compared with the molar volumes of the pure components (less than 0.3% of the molar volume of the pure ionic liquid). For all the considered systems, except for {[C 1 C 2 Im][EtSO 4 ] + water}, positive excess molar volumes were calculated. Finally, an increase of the non-ideality character is observed for all the systems as temperature increases.

  20. Fluorescence and room temperature phosphorescence of 6-bromo-2-naphthol in {beta}-cyclodextrin solution and its selective molecular recognition for cyclohexane

    Energy Technology Data Exchange (ETDEWEB)

    Zhai Yanqiang; Zhang Shuzhen; Xie Jianwei; Liu Changsong

    2003-10-08

    The room temperature phosphorescence (RTP) and fluorescence behavior of 6-bromo-2-naphthol (BN) in water and {beta}-cyclodextrin ({beta}-CD) aerated aqueous solution was investigated. The study of fluorescence behavior at different pH values indicated that three kinds of species of BN (protonated, uncharged and anionic species) formed 1:1 inclusion complexes with {beta}-CD, and RTP and fluorescence emission depended on the pH of the solution. The inclusion complex constants were 430{+-}25 l mol{sup -1} (pH 1.80), 840{+-}25 l mol{sup -1} (pH 5.80), 1850{+-}75 l mol{sup -1} (pH 11.50), respectively. Experimental results elucidated that RTP of the BN/{beta}-CD/cyclohexane solution came from the protonated and uncharged species of BN, but not from the anionic species, though the inclusion constant of the anionic species of BN with {beta}-CD was larger than that of the other two species of BN Selective molecular recognition of BN/{beta}-CD as an RTP sensor for 28 small organic molecules was studied, it was shown that BN/{beta}-CD could be develop as a new RTP sensor with high selectivity molecular recognition ability for cyclohexane.

  1. Fluorescence and room temperature phosphorescence of 6-bromo-2-naphthol in β-cyclodextrin solution and its selective molecular recognition for cyclohexane

    International Nuclear Information System (INIS)

    Zhai Yanqiang; Zhang Shuzhen; Xie Jianwei; Liu Changsong

    2003-01-01

    The room temperature phosphorescence (RTP) and fluorescence behavior of 6-bromo-2-naphthol (BN) in water and β-cyclodextrin (β-CD) aerated aqueous solution was investigated. The study of fluorescence behavior at different pH values indicated that three kinds of species of BN (protonated, uncharged and anionic species) formed 1:1 inclusion complexes with β-CD, and RTP and fluorescence emission depended on the pH of the solution. The inclusion complex constants were 430±25 l mol -1 (pH 1.80), 840±25 l mol -1 (pH 5.80), 1850±75 l mol -1 (pH 11.50), respectively. Experimental results elucidated that RTP of the BN/β-CD/cyclohexane solution came from the protonated and uncharged species of BN, but not from the anionic species, though the inclusion constant of the anionic species of BN with β-CD was larger than that of the other two species of BN Selective molecular recognition of BN/β-CD as an RTP sensor for 28 small organic molecules was studied, it was shown that BN/β-CD could be develop as a new RTP sensor with high selectivity molecular recognition ability for cyclohexane

  2. Transpassive dissolution of alloy 625, chromium, nickel, and molybdenum in high-temperature solutions containing hydrochloric acid and oxygen

    International Nuclear Information System (INIS)

    Kritzer, P.; Boukis, N.; Dinjus, E.

    2000-01-01

    Coupons of nickel, molybdenum, chromium, and the nickel-based Alloy 625 (UNS 06625) were corroded in strongly oxidizing hydrochloric acid (HCl) solutions at 350 C and a pressure (p) of 24 MPa, with reaction times between 0.75 h and 50 h. For Alloy 625, the effect of surface roughness also was investigated. Nickel and molybdenum showed strong material loss after only 5 h of reaction as a result of the instability of the solid oxides formed under experimental conditions. The attack on chromium started at the grain boundaries. At longer reaction times, thick, spalling oxide layers formed on the surface. The attack on Alloy 625 also started at the grain boundaries and at inclusions leading to the formation of small pits. On polished surfaces, the growth of these pits occurred faster than on nonpolished surfaces, but fewer pits grew. Corrosion products formed at the surface consisted of oxygen and chromium. On isolated spots, nickel- and chlorine-containing products also were found

  3. Effect of molecular topology on the transport properties of dendrimers in dilute solution at Θ temperature: A Brownian dynamics study

    Science.gov (United States)

    Bosko, Jaroslaw T.; Ravi Prakash, J.

    2008-01-01

    Structure and transport properties of dendrimers in dilute solution are studied with the aid of Brownian dynamics simulations. To investigate the effect of molecular topology on the properties, linear chain, star, and dendrimer molecules of comparable molecular weights are studied. A bead-spring chain model with finitely extensible springs and fluctuating hydrodynamic interactions is used to represent polymer molecules under Θ conditions. Structural properties as well as the diffusivity and zero-shear-rate intrinsic viscosity of polymers with varied degrees of branching are analyzed. Results for the free-draining case are compared to and found in very good agreement with the Rouse model predictions. Translational diffusivity is evaluated and the difference between the short-time and long-time behavior due to dynamic correlations is observed. Incorporation of hydrodynamic interactions is found to be sufficient to reproduce the maximum in the intrinsic viscosity versus molecular weight observed experimentally for dendrimers. Results of the nonequilibrium Brownian dynamics simulations of dendrimers and linear chain polymers subjected to a planar shear flow in a wide range of strain rates are also reported. The flow-induced molecular deformation of molecules is found to decrease hydrodynamic interactions and lead to the appearance of shear thickening. Further, branching is found to suppress flow-induced molecular alignment and deformation.

  4. Passivation behaviour of stainless steel (UNS N-08028) in industrial or simplified phosphoric acid solutions at different temperatures

    International Nuclear Information System (INIS)

    Ben Salah, M.; Sabot, R.; Refait, Ph.; Liascukiene, I.; Méthivier, C.; Landoulsi, J.; Dhouibi, L.

    2015-01-01

    Highlights: • Industrial phosphoric acid is less aggressive than simulated industrial acid. • Polyphosphate film in Industrial acid is reinforced by calcium and sulfate. • Passive film thickness is obtained by the power law model from EIS measurements. • Passive film of Sanicro28 becomes more resistive towards corrosion with exposure time in industrial acid. • XPS measurements coupled to Raman spectroscopy reveal the corrosion products formed in simulated acid. - Abstract: The corrosion behaviour of Sanicro28, in industrial phosphoric acid and simplified solution of pure H_3PO_4 containing sulphates and chlorides, is investigated during 48 h between 20 and 80 °C. Results show higher corrosion resistance in the industrial medium. Film thickness evaluated by EIS remains constant in industrial acid due to polyphosphate that promotes crystallisation of the Cr_2O_3 inner layer. Conversely, the passive film is partially destroyed at 80 °C in simplified acid. XPS and Raman analysis show that phosphate and molybdenum are both present in the passive film and in corrosion products. The role of Ca present in the industrial acid is discussed.

  5. Effect of precursor solutions stirring on deep level defects concentration and spatial distribution in low temperature aqueous chemical synthesis of zinc oxide nanorods

    Directory of Open Access Journals (Sweden)

    Hatim Alnoor

    2015-08-01

    Full Text Available Hexagonal c-axis oriented zinc oxide (ZnO nanorods (NRs with 120-300 nm diameters are synthesized via the low temperature aqueous chemical route at 80 °C on silver-coated glass substrates. The influence of varying the precursor solutions stirring durations on the concentration and spatial distributions of deep level defects in ZnO NRs is investigated. Room temperature micro-photoluminesnce (μ-PL spectra were collected for all samples. Cathodoluminescence (CL spectra of the as-synthesized NRs reveal a significant change in the intensity ratio of the near band edge emission (NBE to the deep-level emission (DLE peaks with increasing stirring durations. This is attributed to the variation in the concentration of the oxygen-deficiency with increasing stirring durations as suggested from the X-ray photoelectron spectroscopy analysis. Spatially resolved CL spectra taken along individual NRs revealed that stirring the precursor solutions for relatively short duration (1-3 h, which likely induced high super saturation under thermodynamic equilibrium during the synthesis process, is observed to favor the formation of point defects moving towards the tip of the NRs. In contrary, stirring for longer duration (5-15 h will induce low super saturation favoring the formation of point defects located at the bottom of the NRs. These findings demonstrate that it is possible to control the concentration and spatial distribution of deep level defects in ZnO NRs by varying the stirring durations of the precursor solutions.

  6. Room temperature synthesis of PbSe quantum dots in aqueous solution: Stabilization by interactions with ligands

    Science.gov (United States)

    Primera-Pedrozo, Oliva M.; Arslan, Zikri; Rasulev, Bakhtiyor; Leszczynski, Jerzy

    2011-01-01

    An aqueous route of synthesis is described for rapid synthesis of lead selenide quantum dots (PbSe QDs) at room temperature in an attempt to produce water-soluble and stable nanocrystals. Several thiol-ligands, including thioglycolic acid (TGA), thioglycerol (TGC), 3-mercaptopropionic acid (MPA), 2-mercaptoethyleamine hydrochloride (MEA), 6-mercaptohexanoic acid (MHA), and L-cysteine (L-cys), were used for capping/stabilization of PbSe QDs. The effects of the ligands on the stability of PbSe QDs were evaluated for a period of two months at room temperature under normal light conditions and at 4 °C in dark. The TGA- and MEA-capped QDs exhibited the highest stability prior to purification, almost two months when kept in dark at 4 °C. However, the stability of TGA-capped QDs was reduced substantially after purification to about 5 days under same conditions, while MEA-capped QDs did not show any significant instability. The stabilization energies of Pb-thiolate complexes determined by theoretical DFT simulations supported the experimental results. The PbSe QDs capped with TGA, MPA and MEA were successfully purified and re-dispersed in water, while those stabilized with TGC, MHA and L-cys aggregated during purification attempts. The purified PbSe QDs possess very susceptible surface resulting in poor stability for about 30 – 45 min after re-dispersion in water. In the presence of an excess of free ligand, the stability increased up to 5 days for TGA-capped QDs at pH 7.19, 9 –12 days for MPA-capped QDs at pH 7.3–7.5 and 45–47 days for MEA-capped QDs at pH 7.35. X-Ray Diffraction (XRD) results showed that the QDs possess a cubic rock salt structure with the most intense peaks located at 2θ = 25.3° (200) and 2θ = 29.2° (100). TEM images showed that the size of the QDs ranges between 5 and 10 nm. ICP-MS results revealed that Pb:Se ratio was 1.26, 1.28, 3.85, 1.18, and 1.31 for the QDs capped with TGA, MPA, MEA, L-Cys, and TGC, respectively. The proposed method

  7. Intergranular corrosion of 13Cr and 17Cr martensitic stainless steels in accelerated corrosive solution and high-temperature, high-purity water

    International Nuclear Information System (INIS)

    Ozaki, Toshinori; Ishikawa, Yuichi

    1988-01-01

    Intergranular corrosion behavior of 13Cr and 17Cr martensitic stainless steels was studied by electrochemical and immersing corrosion tests. Effects of the mEtallurgical and environmental conditions on the intergranular corrosion of various tempered steels were examined by the following tests and discussed. (a) Anodic polarization measurement and electrolytical etching test in 0.5 kmol/m 3 H 2 SO 4 solution at 293 K. (b) Immersion corrosion test in 0.88 kmol/m 3 HNO 3 solution at 293 K. (c) Long-time immersion test for specimens with a crevice in a high purity water at 473 K∼561 K. It was found from the anodic polarization curves in 0.5 kmol/m 3 H 2 SO 4 solution-at 293 K that the steels tempered at 773∼873 K had susceptibility to intergranular corrosion in the potential region indicating a second current maximum (around-0.1 V. vs. SCE). But the steel became passive in the more noble potential region than the second current peak potential, while in the less noble potential region general corrosion occurred independent of its microstructure. The intergranular corrosion occurred due to the localized dissolution along the pre-austenitic grain boundary and the martensitic lath boundary. It could be explained by the same dissolution model of the chromium depleted zone as proposed for the intergranular corrosion of austenitic and ferritic stainless steels. The intergranular corrosion occurred entirely at the free surface in 0.88 kmol/m 3 HNO 3 solution, while in the high temperature and high purity water only the entrance of the crevice corroded. It was also suggested that this intergranular corrosion might serve as the initiation site for stress corrosion cracking of the martensitic stainless steel. (author)

  8. Rheological behaviour of some saccharides in aqueous potassium chloride solutions over temperature range (288.15 to 318.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Banipal, Parampaul K., E-mail: pkbanipal@yahoo.co [Department of Chemistry, Guru Nanak Dev University, Amritsar 143005 (India); Chahal, Amanpreet K.; Singh, Vickramjeet [Department of Chemistry, Guru Nanak Dev University, Amritsar 143005 (India); Banipal, Tarlok S. [Department of Applied Chemistry, Guru Nanak Dev University, Amritsar 143005 (India)

    2010-08-15

    The viscosities, {eta} of mono-, di-, tri-saccharides and methylglycosides, viz., D(+)-xylose (XYL), D(-)-arabinose (ARA), D(-)-ribose (RIB), D(-)-fructose (FRU), D(+)-galactose (GAL), D(+)-mannose (MAN), D(+)-glucose (GLU), D(+)-melibiose (MEL), D(+)-cellobiose (CEL), D(+)-lactose monohydrate (LAC), D(+)-maltose monohydrate (MAL), D(+)-trehalose dihydrate (TRE), sucrose (SUC), D(+)-raffinose pentahydrate (RAF), {alpha}-methyl-D(+)-glucoside ({alpha}-Me-GLU), methyl-{alpha}-D-xylopyranoside (Me-{alpha}-XYL), and methyl-{beta}-D-xylopyranoside (Me-{beta}-XYL) in water and in (0.5, 1.0, 2.0, and 3.0) mol . kg{sup -1} aqueous solutions of potassium chloride (KCl) have been determined at T = (288.15, 298.15, 308.15, and 318.15) K from efflux time measurements by using a capillary viscometer. Densities used to determine viscosities have been reported earlier. The viscosity data have been utilized to determine the viscosity B-coefficients employing the Jones-Dole equation at different temperatures. From these data, the viscosity B-coefficients of transfer, {Delta}{sub t}B have been estimated for the transfer of various saccharides/methylglycosides from water to aqueous potassium chloride solutions. The {Delta}{sub t}B values have been found to be positive, whose magnitude increases with the increase in concentration of potassium chloride in all cases. The dB/dT coefficients, pair, {eta}{sub AB} and triplet, {eta}{sub ABB} viscometric interaction coefficients have also been determined. Gibbs free energies of activation and related thermodynamic parameters of activation of viscous flow have been determined employing Feakin's transition-state theory. The signs and magnitudes of various parameters have been discussed in terms of solute-solute and solute-solvent interactions occurring in these solutions. The effect of substitution of -OH by methoxy group, -OCH{sub 3} has also been discussed.

  9. Room-temperature synthesis of Zn(0.80)Cd(0.20)S solid solution with a high visible-light photocatalytic activity for hydrogen evolution.

    Science.gov (United States)

    Wang, Dong-Hong; Wang, Lei; Xu, An-Wu

    2012-03-21

    Visible light photocatalytic H(2) production from water splitting is of great significance for its potential applications in converting solar energy into chemical energy. In this study, a series of Zn(1-x)Cd(x)S solid solutions with a nanoporous structure were successfully synthesized via a facile template-free method at room temperature. The obtained solid solutions were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS) and N(2) adsorption-desorption analysis. The solid solutions show efficient photocatalytic activity for H(2) evolution from aqueous solutions containing sacrificial reagents S(2-) and SO(3)(2-) under visible-light irradiation without a Pt cocatalyst, and loading of the Pt cocatalyst further improves the visible-light photocatalytic activity. The optimal photocatalyst with x = 0.20 prepared at pH = 7.3 displays the highest activity for H(2) evolution. The bare and 0.25 wt% Pt loaded Zn(0.80)Cd(0.20)S nanoparticles exhibit a high H(2) evolution rate of 193 μmol h(-1) and 458 μmol h(-1) under visible-light irradiation (λ ≥ 420 nm), respectively. In addition, the bare and 0.25 wt% Pt loaded Zn(0.80)Cd(0.20)S catalysts show a high H(2) evolution rate of 252 and 640 μmol h(-1) under simulated solar light irradiation, respectively. Moreover, the Zn(0.80)Cd(0.20)S catalyst displays a high photocatalytic stability for H(2) evolution under long-term light irradiation. The incorporation of Cd in the solid solution leads to the visible light absorption, and the high content of Zn in the solid solution results in a relatively negative conduction band, a modulated band gap and a rather wide valence bandwidth, which are responsible for the excellent photocatalytic performance of H(2) production and for the high photostability

  10. Ionic liquids as electrolytes for non-aqueous solutions electrochemical supercapacitors in a temperature range of 20 °C-80 °C

    Science.gov (United States)

    Zhang, Lei; Tsay, Ken; Bock, Christina; Zhang, Jiujun

    2016-08-01

    To increase the operating temperature of the supercapacitors (SCs) without compromising their high cycle-life, several typical fluoro- and non-fluoro containing ionic liquids (EMI-mesylate, EMI-hydrogen sulfate, PP13-triflate, PP13-TFSI, and EMI-TFSI, as shown in Fig. 1) are studied as the electrolytes to prepare organic solutions for SC performance measurements using a two-electrode cell. Both cyclic voltammograms and charge/discharge curves at various temperatures such as 20, 40, 60 and 80 °C are collected. At 60 °C, the increased performance order in both rating and cyclability measurements are found to be as follows: 1) EMI-hydrogen sulfate < PP13-TFSI < EMI-mesylate < PP13-triflate < EMI-TFSI for rating; and 2) EMI-hydrogen sulfate < EMI-mesylate < PP13-Triflate < PP13-TFSI < EMI-TFSI for life-time. The fluoro-containing group of ILs, i.e., PP13-Triflate, PP13-TFSI and EMI-TFSI can give a specific capacitance between 100 and 170 F/g for various scan rates for a conventional carbon electrode, and an extended lifetime test of 10, 000 cycles with a capacitance degradation of less than 10%, indicating that these two ion liquids can be used for SC electrolytes operated at high temperature.

  11. Partial molar volumes of organic solutes in water. XXVII. Two aliphatic polyethers (triglyme, tetraglyme) at temperatures T = 298–573 K and pressures up to 30 MPa

    International Nuclear Information System (INIS)

    Cibulka, Ivan

    2016-01-01

    Highlights: • Standard molar volumes of two linear aliphatic polyethers in water are presented. • Data were obtained in the range T from (298 to 573) K and p up to 30 MPa. • Data combined with those obtained previously are analyzed and compared with standard molar volumes of cyclic ethers. - Abstract: Densities of dilute aqueous solutions of two linear aliphatic polyethers: 2,5,8,11-tetraoxadodecane (triethylene glycol dimethyl ether, triglyme) and 2,5,8,11,14-pentaoxapentadecane (tetraethylene glycol dimethyl ether, tetraglyme), measured in the temperature range from (298 to 573) K and at pressures up to 30 MPa using an automated flow vibrating-tube densimeter are reported. Standard molar volumes were evaluated from the measured data. The present values complement previous measurements performed for the title polyethers at atmospheric pressure in the temperature range from (278 to 343) K and extend the knowledge to temperature and pressure ranges in which the data on standard molar volumes for lower members of the homologous series (monoglyme, diglyme) are already available.

  12. Effect of Low-Temperature Environment on Stress Corrosion Cracking Behavior of X80 Pipeline Steel in Simulated Alkaline Soil Solution

    Science.gov (United States)

    Xie, Fei; Wang, Dan; Wu, Ming; Yu, Chengxiang; Sun, Dongxu; Yang, Xu; Xu, Changhao

    2018-04-01

    The stress corrosion cracking (SCC) of X80 pipeline steel in simulated alkaline soil solution under different temperatures was investigated by slow-strain-rate testing, scanning electron microscopy and energy-dispersive spectroscopy. Results showed that the fracture was transgranular and brittle at 273 K to 278 K (0 °C to 5 °C), and the metal surface was dissolved by a large number of chloride ions. Furthermore, hydrogen embrittlement was caused by the hydrogen atom extended to the high-stress region. The fracture process was controlled by hydrogen-induced cracking, and SCC was highly sensitive at this stage. At 288 K to 298 K (15 °C to 25 °C), the fracture morphology was attributed to the mixed mode of ductile and brittle fractures, the fracture process was controlled by the mechanism of hydrogen-induced cracking and anodic dissolution, and the susceptibility to SCC decreased. When the temperature reached 308 K to 318 K (35 °C to 45 °C), the fracture was mainly intergranular and ductile, the fracture process was controlled by anodic dissolution, and SCC sensitivity was the smallest in this temperature range.

  13. Lanthanide doped BaTiO{sub 3}−SrTiO{sub 3} solid-solution phosphors: Structure, optical spectroscopy and upconverted temperature sensing behavior

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Daqin, E-mail: dqchen@hdu.edu.cn; Xu, Wei; Zhou, Yang; Chen, Yan, E-mail: chenyan@hdu.edu.cn

    2016-08-15

    Lanthanide doped Ba{sub 1-x}Sr{sub x}TiO{sub 3} (x = 0–1) solid-solution phosphors were successfully prepared by a conventional solid-state reaction. Using Eu{sup 3+} dopants as the structural probe, the variation of {sup 5}D{sub 0} → {sup 7}F{sub 2}/{sup 5}D{sub 0} → {sup 7}F{sub 1} emission intensity ratio with increase of Eu{sup 3+} content and the excitation-wavelength-dependent luminescence in the Ba{sub 1-x}Sr{sub x}TiO{sub 3} sample were demonstrated to be originated from the different emission behaviors of Eu{sup 3+} in Ba{sup 2+}/Sr{sup 2+} site and Ti{sup 4+} site. Furthermore, upconversion luminescence for the Yb{sup 3+}/Er{sup 3+} co-doped Ba{sub 1-x}Sr{sub x}TiO{sub 3} samples were investigated, and it was found that the emission intensity of Yb{sup 3+}/Er{sup 3+}: Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3} phosphor was about 5 and 2 times as high as those of Yb{sup 3+}/Er{sup 3+}: BaTiO{sub 3} and Yb{sup 3+}/Er{sup 3+}: SrTiO{sub 3} ones. Using the investigated Yb{sup 3+}/Er{sup 3+}: Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3} solid-solution as the optical thermometric medium, the temperature sensitivity was determined to be 0.76% K{sup −1} at the temperature of 610 K based on the temperature-dependent fluorescence intensity ratio of the thermally coupled {sup 2}H{sub 11/2} and {sup 4}S{sub 3/2} emitting-states of Er{sup 3+}. - Highlights: • Lanthanide doped Ba{sub 1-x}Sr{sub x}TiO{sub 3} (x = 0–1) solid-solutions were fabricated. • Excitation-wavelength-dependent Eu{sup 3+} emissions were recorded. • Enhanced Er{sup 3+} luminescence was realized by partial substitution of Ba{sup 2+} by Sr{sup 2+}. • T-sensitive emissions of two Er{sup 3+} thermally coupled states were observed. • The upconversion phosphor exhibited a high sensitivity of 0.76% K{sup −1}.

  14. Standard molar volumes and heat capacities of aqueous solutions of sodium trifluoromethanesulfonate at temperatures up to 573 K and pressures to 28 MPa

    International Nuclear Information System (INIS)

    Pourtier, Emilie; Ballerat-Busserolles, Karine; Majer, Vladimir; Šedlbauer, Josef

    2013-01-01

    Highlights: ► Original HT/HP data for NaTr(aq) obtained using non-commercial instruments. ► First heat capacity data for NaTr(aq) at conditions remote from ambient. ► Correction for association when calculating stand. therm. properties of Tr(aq) anion. - Abstract: Densities and heat capacities of aqueous solutions of sodium trifluoromethanesulfonate (sodium triflate) of concentrations from 0.025 to 0.3 mol · kg −1 were measured with high temperature, high pressure custom-made instruments at temperatures up to 573 K and at pressures up to 28 MPa. Standard molar volumes and standard molar heat capacities were obtained via extrapolation of the apparent molar properties to infinite dilution. The results for volumetric properties are consistent with earlier literature data, but no previous measurements exist for heat capacities of sodium triflate at superambient conditions. The new data were used for calculating the standard molar volumes and heat capacities for the triflate anion and compared with the results for triflic acid that should be essentially identical within the expected error margins. At temperatures above 473 K an effort was made to refine the processing of literature data for HCl(aq), taking into account its partial association, and subsequently to modify the value for Na + ion calculated from the standard thermodynamic values of NaCl(aq) where its ion pairing was already considered. This approach yields reasonable agreement at high temperatures between the values for triflate ion calculated from its salt and those for triflic acid.

  15. Volumetric, acoustic and viscometric behaviour of dipotassium hydrogen phosphate and disodium hydrogen phosphate in aqueous solution of N-acetyl glycine at different temperatures

    International Nuclear Information System (INIS)

    Kumar, Harsh; Singla, Meenu; Mittal, Heena

    2016-01-01

    Highlights: • Densities, speeds of sound, viscosities of phosphate salts in aqueous N-acetyl glycine. • Large values of partial molar volume for dipotassium hydrogen phosphate. • Partial molar volume of transfer are positive for phosphate salts. • Positive B-coefficient values indicate ion–solvent interactions. - Abstract: Densities, speeds of sound and viscosities of dipotassium hydrogen phosphate (DPHP) and disodium hydrogen phosphate (DSHP) in aqueous solutions of N-acetyl glycine (AcGly) are reported at different temperatures. Densities and speeds of sound have been used to calculate apparent molar volume, apparent molar isentropic compression, partial molar volume, partial molar isentropic compression, partial molar volume of transfer, partial molar isentropic compression of transfer and partial molar expansivity. Pair and triplet interaction coefficients have also been calculated. Experimental viscosities have been used to determine B-coefficients. Further pair and triplet interaction coefficients have also been calculated. The results are discussed in terms of solute–solvent interactions.

  16. Solution of the point kinetics equations in the presence of Newtonian temperature feedback by Pade approximations via the analytical inversion method

    International Nuclear Information System (INIS)

    Aboanber, A E; Nahla, A A

    2002-01-01

    A method based on the Pade approximations is applied to the solution of the point kinetics equations with a time varying reactivity. The technique consists of treating explicitly the roots of the inhour formula. A significant improvement has been observed by treating explicitly the most dominant roots of the inhour equation, which usually would make the Pade approximation inaccurate. Also the analytical inversion method which permits a fast inversion of polynomials of the point kinetics matrix is applied to the Pade approximations. Results are presented for several cases of Pade approximations using various options of the method with different types of reactivity. The formalism is applicable equally well to non-linear problems, where the reactivity depends on the neutron density through temperature feedback. It was evident that the presented method is particularly good for cases in which the reactivity can be represented by a series of steps and performed quite well for more general cases

  17. Physical, optical and electrical properties of copper selenide (CuSe) thin films deposited by solution growth technique at room temperature

    International Nuclear Information System (INIS)

    Gosavi, S.R.; Deshpande, N.G.; Gudage, Y.G.; Sharma, Ramphal

    2008-01-01

    Copper selenide (CuSe) thin films are grown onto amorphous glass substrate from an aqueous alkaline medium using solution growth technique (SGT) at room temperature. The preparative parameters were optimized to obtain good quality of thin films. The as-deposited films were characterized for physical, optical and electrical properties. X-ray diffraction (XRD) pattern reveals that the films are polycrystalline in nature. Energy dispersive analysis by X-ray (EDAX) shows formation of stoichiometric CuSe compound. Uniform deposition of CuSe thin films on glass substrate was observed from scanning electron microscopy (SEM) and atomic force microscopy (AFM) micrographs. Average grain size was determined to 144.53 ± 10 nm using atomic force microscopy. The band gap was found to be 2.03 eV with direct band-to-band transition. Semi-conducting behaviour was observed from resistivity measurements. Ohmic behaviour was seen from I-V curve with good electrical conductivity

  18. Effect of Solution Molarity, Substrate Temperature and Spray Time on The Structural and Optical Properties Of ZnO Thin Films Deposited By Spray Pyrolysis

    International Nuclear Information System (INIS)

    Ramadan, A.A.; Hashem, H. M.; El-Sayed, S. M.; Ashour, A.H.; Abdel-Haleem, S.M.

    2013-01-01

    Zinc oxide thin films were deposited on a glass substrate by spray pyrolysis technique using solution of zinc acetate and air as the carrier gas. Effects of solution molarity, substrate temperature and spray time on films properties were investigated. All films deposited were characterized using X-ray diffraction for structural characterization and UV-VIS transmission spectrophotometry for optical properties. According to the analytical method, the type of crystal lattice was found to be hexagonal and X-ray diffraction (XRD) patterns showed that the films deposited were polycrystalline with (002) plane as preferential orientation. The values of lattice constant, grain size, micro strain and dislocation density of all samples were calculated. In addition, Optical behaviors of film samples were analyzed by obtaining transmission spectra, in the wavelength range of 350-800 nm. The UV-VIS spectroscopy shows the high transparency of ZnO films in the UV region. An optimization of the films has been carried out to determine the best preparation conditions.

  19. Stress corrosion cracking of Inconel 600 in aqueous solutions at elevated temperature. Pt. II. Effects of chloride and sulphate ions on the electrochemical behaviour of Inconel 600

    International Nuclear Information System (INIS)

    Ashour, E.A.; Schneider, F.; Mummert, K.

    1997-01-01

    For pt.I see ibid., p.151-6, 1997. The influencing effects of temperature, potential and electrolyte composition on the electrochemical behaviour of Inconel 600 in aqueous solutions are presented. Considering these effects the connection between the data have been obtained from chemo-mechanical fracture investigation on CT-samples in Part I of this paper and pitting corrosion are discussed. The results have shown that chloride ions depassivate the surfaces of cracks locally and hinder the formation of a new protective oxide layer on the fracture surfaces. Furthermore, chloride promotes the dissolution of metal and initiates the cracking, respectively. The resulting crevice corrosion promotes an increase of hydrogen absorption by the metal. The increase of the hydrogen content of the metal influences the mechanical fracture behaviour. Contrary, sulphate ions inhibit the initiation of corrosion mainly due to a hinderance of chloride ions adsorption on active sites of the fracture surfaces. The initiation of localized corrosion in the crevice region may be stimulated by chromate ions formed by oxidation of chromium from the oxide layer or the base metal in oxygen containing solutions. (orig.)

  20. Effect of storage temperature and osmotic pre-treatment with alternative solutes on the shelf-life of gilthead seabream (Sparus aurata fillets

    Directory of Open Access Journals (Sweden)

    Theofania N. Tsironi

    2017-01-01

    Osmotic pre-treatment led to significant shelf-life extension of fillets, in terms of microbial growth, chemical changes and organoleptic deterioration. The pre-treatment with the alternative solutes led to depression of the freezing point (−1.8, −2.6, −3.2 and −3.5 °C for the untreated samples and the osmotically pre-treated with HDM, HDM + treh and HDM + gluc, respectively. TVB-N values were higher in untreated samples, followed by osmotically treated fillets, mainly at higher storage temperatures (i.e. 10 and 15 °C. Based on the mathematical models for sensory evaluation scoring, the shelf-life was 12, 19, 22 and 22 days at 0 °C for untreated and osmotically pre-treated with HDM, HDM + treh and HDM + gluc fish slices, respectively, while the respective values at −3 °C were 21, 35, 38 and 38 days. The alternative solutes had no significant effect on the quality and shelf-life of pre-treated fish fillet during storage at refrigerated conditions.

  1. The effect of temperature and concentration on the corrosion inhibition mechanism of an amphiphilic amido-amine in CO2 saturated solution

    International Nuclear Information System (INIS)

    Desimone, M.P.; Gordillo, G.; Simison, S.N.

    2011-01-01

    Highlights: → Behaviour of N-[2-[(2-aminoethyl)amino]ethyl]-9-octadecenamide (AAOA) as CO 2 corrosion inhibitor. → The adsorption of the AAOA corrosion inhibitor obeys a Frumkin adsorption isotherm. → The inhibition efficiency of the AAOA depends on temperature and concentration. → There is a change in the adsorption mode of the inhibitor with concentration. → AAOA is mainly physi- or chemisorbed for low or high concentrations, respectively. - Abstract: The corrosion inhibition mechanism of the N-[2-[(2-aminoethyl)amino]ethyl]-9-octadecenamide on mild steel surface in CO 2 -saturated 5% NaCl solution has been studied. The inhibition efficiency decreases with increasing temperature. Adsorption of the inhibitor studied is found to follow the Frumkin adsorption isotherm. EIS results show that the mechanism of its corrosion inhibition at concentrations higher than critical micelle concentration is by forming a protective porous bi-layer. The activation energy, thermodynamic parameters and electrochemical results reveal a change in the adsorption mode of the inhibitor studied: the inhibitor could primarily be physically adsorbed at low concentrations, while chemisorption is favoured as concentration increases.

  2. Low-temperature CO oxidation over Cu/Pt co-doped ZrO2 nanoparticles synthesized by solution combustion.

    Science.gov (United States)

    Singhania, Amit; Gupta, Shipra Mital

    2017-01-01

    Zirconia (ZrO 2 ) nanoparticles co-doped with Cu and Pt were applied as catalysts for carbon monoxide (CO) oxidation. These materials were prepared through solution combustion in order to obtain highly active and stable catalytic nanomaterials. This method allows Pt 2+ and Cu 2+ ions to dissolve into the ZrO 2 lattice and thus creates oxygen vacancies due to lattice distortion and charge imbalance. High-resolution transmission electron microscopy (HRTEM) results showed Cu/Pt co-doped ZrO 2 nanoparticles with a size of ca. 10 nm. X-ray diffraction (XRD) and Raman spectra confirmed cubic structure and larger oxygen vacancies. The nanoparticles showed excellent activity for CO oxidation. The temperature T 50 (the temperature at which 50% of CO are converted) was lowered by 175 °C in comparison to bare ZrO 2 . Further, they exhibited very high stability for CO reaction (time-on-stream ≈ 70 h). This is due to combined effect of smaller particle size, large oxygen vacancies, high specific surface area and better thermal stability of the Cu/Pt co-doped ZrO 2 nanoparticles. The apparent activation energy for CO oxidation is found to be 45.6 kJ·mol -1 . The CO conversion decreases with increase in gas hourly space velocity (GHSV) and initial CO concentration.

  3. Seven harmonic susceptibility in oxygen and hydrogen loading of sintered YBCO by μs pulsed electrolysis in an aqueous solution at room temperature

    International Nuclear Information System (INIS)

    Tripodi, P.; Di Gioacchino, D.; Celani, F.

    1996-09-01

    The complex AC susceptibility of high T c superconducting materials has been described in terms of the first seven harmonic component of Fourier series. Has been measured the χ' n and χ n (n=1,7) of sintered YBa 2 Cu 3 O 7-x (YBCO) bulk oxygen and hydrogen loaded samples versus amplitude and frequency of AC magnetic field at fixed temperature. The sample have been loaded by μs current pulses electrolysis in an aqueous solution (0.3N LiOH+H 2 O) at room temperature. In addition to the simplicity of the experimental setup, this procedure allows to obtain extremely high equivalent hydrogen/oxygen gas pressure on the surface of the electrodes. The YBCO electrode is polarized by short pulse width (0.5-10 μs) and high power (120 W) peaks with a variable repetition rate (0.1-10000 Hz). The pulses are obtained by an home.made pulse generator. The difference in the behavior of the susceptibilities harmonic component between the deficiency and oxygen or hydrogen loaded samples give us the possibility to connect the susceptibilities with variations of the flux pinning in respect to normal losses in the superconducting materials. The loading can be a good probe to have information on the mechanism of the processes that sustain the critical current density Jc in this situation these affects appear strongly dependent on the loading conditions. By comparison of this measurements has been observed drastic change in behavior of susceptibility

  4. Manufacture of pooled platelets in additive solution and storage in an ELX container after an overnight warm temperature hold of platelet-rich plasma.

    Science.gov (United States)

    Alhumaidan, Hiba; Cheves, Tracey; Holme, Stein; Sweeney, Joseph D

    2011-10-01

    The processing of whole blood-derived platelet-rich plasma (PRP) to a platelet concentrate and platelet-poor plasma is currently performed within 8 hours to comply with the requirements to manufacture fresh frozen plasma. Maintaining PRP at room temperature for a longer period can have the advantage of shifting the completion of component manufacture onto day shifts. Pairs of ABO-identical prepooled platelets were manufactured by the PRP method, using the current approach with platelet storage in a CLX HP container (Pall Medical, Covina, CA) and plasma, or a novel approach with an 18- to a 24-hour room temperature hold of the PRP and the manufacture of pooled platelets in a glucose-containing additive solution (AS) and storage in a new ELX container (Pall Medical). Standard in vitro assays were performed on days 2, 5, and 7. The results showed that the AS platelets in ELX have in vitro characteristics that are equivalent or superior to those of the standard product.

  5. Corrosion behaviour of sensitized and unsensitized Alloy 900 (UNS 1.4462) in concentrated aqueous lithium bromide solutions at different temperatures

    International Nuclear Information System (INIS)

    Leiva-Garcia, R.; Munoz-Portero, M.J.; Garcia-Anton, J.

    2010-01-01

    Duplex stainless steels can undergo microstructural changes if they are heated improperly. When that happens, duplex stainless steels are sensitized and intermetallic phases appear. The high Chromium and Molybdenum content promotes the formation of secondary phases as a consequence of the heat treatment. These secondary phases, which are rich in alloying elements, such as Cr and Mo, deplete these elements from the neighbouring phases, leading to a reduction in corrosion resistance. In order to study the influence of the secondary phases on the corrosion parameters, samples of duplex stainless steel, Alloy 900 (UNS 1.4462), have been heated in argon atmosphere at 825 deg. C for 1 h. The corrosion behaviour of sensitized and unsensitized Alloy 900 has been analyzed in a concentrated aqueous lithium bromide (LiBr) solution of 992 g/L by means of cyclic potentiodynamic curves. Secondary phase presence reduces the pitting potential value of Alloy 900. Besides, the pitting potential decreases with temperature. On the other hand, the corrosion potential and open circuit potential values increase with temperature and sensitization.

  6. Investigation of the Effects of Solution Temperature on the Corrosion Behavior of Austenitic Low-Nickel Stainless Steels in Citric Acid using Impedance and Polarization Measurements

    Directory of Open Access Journals (Sweden)

    Mulimbayan Francis M.

    2015-01-01

    Full Text Available Stainless steels may be classified according to alloy microstructure – ferritic, austenitic, martensitic, duplex, and precipitation hardening grades. Among these, austenitic grade has the largest contribution to market due to the alloy’s numerous industrial and domestic applications. In this study, the corrosion behavior of low-Nickel stainless steel in citric acid was investigated using potentiodynamic polarization techniques and Electrochemical Impedance Spectroscopy (EIS. The corrosion current density which is directly related to corrosion rate was extracted from the generated anodic polarization curve. Increasing the temperature of the citric acid resulted to increased corrosion current densities indicating higher corrosion rates at initial corrosion condition. EIS was performed to generate Nyquist plots whose shape and size depicts the corrosion mechanism and corrosion resistance of the alloy in citric acid, respectively. All the generated Nyquist plots have depressed semi-circle shapes implying that corrosion process takes place with charge-transfer as the rate-determining step. Based from the extracted values of polarization resistance (Rp, the temperature of the solution has negative correlation with the corrosion resistance of the studied alloy.

  7. One-step synthesis of lightly doped porous silicon nanowires in HF/AgNO3/H2O2 solution at room temperature

    International Nuclear Information System (INIS)

    Bai, Fan; Li, Meicheng; Song, Dandan; Yu, Hang; Jiang, Bing; Li, Yingfeng

    2012-01-01

    One-step synthesis of lightly doped porous silicon nanowire arrays was achieved by etching the silicon wafer in HF/AgNO 3 /H 2 O 2 solution at room temperature. The lightly doped porous silicon nanowires (pNWs) have circular nanopores on the sidewall, which can emit strong green fluorescence. The surface morphologies of these nanowires could be controlled by simply adjusting the concentration of H 2 O 2 , which influences the distribution of silver nanoparticles (Ag NPs) along the nanowire axis. A mechanism based on Ag NPs-induced lateral etching of nanowires was proposed to explain the formation of pNWs. The controllable and widely applicable synthesis of pNWs will open their potential application to nanoscale photoluminescence devices. - Graphical abstract: The one-step synthesis of porous silicon nanowire arrays is achieved by chemical etching of the lightly doped p-type Si (100) wafer at room temperature. These nanowires exhibit strong green photoluminescence. SEM, TEM, HRTEM and photoluminescence images of pNWs. The scale bars of SEM, TEM HRTEM and photoluminescence are 10 μm, 20 nm, 10 nm, and 1 μm, respectively. Highlights: ► Simple one-step synthesis of lightly doped porous silicon nanowire arrays is achieved at RT. ► Etching process and mechanism are illustrated with etching model from a novel standpoint. ► As-prepared porous silicon nanowire emits strong green fluorescence, proving unique property.

  8. Free radical formation in deoxyguanosine-5'-monophosphate γ-irradiated in frozen solution. A computer-assisted analysis of temperature-dependent ESR spectra

    International Nuclear Information System (INIS)

    Gregoli, S.; Olast, M.; Bertinchamps, A.

    1977-01-01

    Deoxyguanosine-5'-monophosphate (dGMP) was γ-irradiated at 77 K in frozen aqueous solution and then annealed in a stepwise fashion up to the melting point. During this process, the primary radicals formed in DGMP at 77 K are progressively converted into secondary radical species. This is observed as changes in the spectrum intensity and conformation. Computer-assisted analysis of these temperature-dependent spectra permitted us to identify the transient radical species involved and to draw up single-radical concentration kinetics vs temperature. The radiation chemical behavior of dGMP was found to be quite similar to that of dAMP, investigated previously. In both these purine derivatives, radical anions are converted into radicals of H-addition to C-8, and radical cations are converted into radicals of OH-addition to the same position. In dGMP, however, the cationic channel is only induced under certain experimental conditions (alkaline pH, presence of electron scavengers). At neutral pH, G + radicals are quite stable and finally become deactivated without being converted into secondary GOH radicals. Specific deuterium substitution at carbon C-8, and irradiation in H 2 O or in D 2 O, confirmed that both H + and OH - attachments do occur at C-8, and that both the H + and OH - groups come from the aqueous medium

  9. Increased photocatalytic activity of NiO and ZnO in photodegradation of a model drug aqueous solution: Effect of coupling, supporting, particles size and calcination temperature

    Energy Technology Data Exchange (ETDEWEB)

    Derikvandi, Hadis [Department of Chemistry, Shahreza Branch, Islamic Azad University, P.O. Box 311-86145, Shahreza, Isfahan, Iran (Iran, Islamic Republic of); Young Researchers and Elite Club, Shahreza Branch, Islamic Azad University, Shahreza (Iran, Islamic Republic of); Nezamzadeh-Ejhieh, Alireza, E-mail: arnezamzadeh@iaush.ac.ir [Department of Chemistry, Shahreza Branch, Islamic Azad University, P.O. Box 311-86145, Shahreza, Isfahan, Iran (Iran, Islamic Republic of); Young Researchers and Elite Club, Shahreza Branch, Islamic Azad University, Shahreza (Iran, Islamic Republic of); Razi Chemistry Research Center (RCRC), Shahreza Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of)

    2017-01-05

    Highlights: • Increased photoactivity of hybridized/supported NiO-ZnO whit respect to monocomponent one. • Strong dependence of photocatalytic activity of NiO-ZnO to calcination temperature. • Calcination temperature varied the crystallite forms of the semiconductors. • Red shifts in band gaps of the supported coupled semiconductors whit respect to monocomponent one. - Abstract: Mechanically ball-mill prepared clinoptilolite nanoparticles (NC) were used for increasing photocatalytic activity of NiO and ZnO as alone and binary systems. The semiconductors were supported onto the zeolite during calcination of Ni(II)-Zn(II)-exchanged NC at different calcinations temperatures. XRD, FTIR, SEM-EDX, X-ray mapping, DRS, TEM and BET techniques were used for characterization of the samples. The calcined catalysts at 400 °C for 4 h showed the best photocatalytic activity for metronidazole (MNZ) in aqueous solution. The mole ratio of ZnO/NiO affected the photodegradation efficiency because activity of the coupled catalysts depends to the both e/h production and electron scavenging processes. In the used system, NiO acted as e/h production source and ZnO as an electron sink. Red shifts in band gaps of the supported coupled semiconductors was observed whit respect to monocomponent one, confirming formation of nanoparticles of the semiconductors onto the zeolitic bed. The best activities were obtained for the NiO{sub 1.3}–ZnO{sub 1.5}/NC (NZ-NC) and NiO{sub 0.7}–ZnO{sub 4.3}/NC (NZ{sub 3}-NC) catalysts at pH 3, 1.2 g L{sup −1} of the catalysts and 1 g L{sup −1} of MNZ.

  10. Effect of annealing temperature on a single step processed Cu{sub 2}ZnSnS{sub 4} thin film via solution method

    Energy Technology Data Exchange (ETDEWEB)

    Prabeesh, P.; Selvam, I. Packia; Potty, S.N.

    2016-05-01

    Cu{sub 2}ZnSnS{sub 4} (CZTS) is a promising material for thin film solar cell applications because of its excellent photovoltaic properties, high abundance and non-toxicity. Thin films of CZTS are generally fabricated by vacuum based techniques or by using toxic solvents and these routes reduce its attention as a low cost and environmental friendly material. In this study, we have prepared CZTS through a solution based single step approach using non-toxic chemicals by spin coating and studied the effect of annealing temperature in the range 350–550 °C in nitrogen atmosphere on structural, optical and electrical properties. XRD results revealed the formation of kesterite phase at all annealing temperatures, while the Raman studies indicated Cu{sub 2}SnS{sub 2} impurity phase in the film annealed at 550 °C. Band gap of the films annealed in nitrogen varies from 1.46 eV to 1.56 eV, depending on the annealing temperature. Optimum properties, such as, good crystallinity, dense structure, ideal band gap (1.49 eV) and good absorption coefficient (10{sup 4} cm{sup −1}), were obtained for the film annealed at 500 °C for 30 min in nitrogen. - Highlights: • Prepared CZTS film through one-step liquid based approach using non-toxic chemicals. • Studied the effect of N{sub 2} annealing on structural, optical and electrical properties. • The phase pure CZTS absorber film exhibited excellent photovoltaic properties • The film annealed at 500 °C for 30 min in nitrogen exhibited optimum properties.

  11. Liquid-liquid phase separation in dilute solutions of poly(styrene sulfonate) with multivalent cations: Phase diagrams, chain morphology, and impact of temperature

    Science.gov (United States)

    Hansch, Markus; Hämisch, Benjamin; Schweins, Ralf; Prévost, Sylvain; Huber, Klaus

    2018-01-01

    The dilute solution behavior of sodium poly(styrene sulfonate) is studied in the presence of trivalent Al3+ and bivalent Ba2+ cations at various levels of excess NaCl. The study evaluates the phase behavior and the morphology of the polyelectrolyte chains with increasing extent of decoration with the Al3+ and Ba2+ cations and analyses the effect of temperature on these decorated chains. The phase behavior is presented in the form of the cation concentration versus the respective poly(styrene sulfonate) concentration, recorded at the onset of precipitation. Whereas poly(styrene sulfonate) with Al3+ exhibits a linear phase boundary, denoted as the "threshold line," which increases with increasing poly(styrene sulfonate) concentration, Ba2+ cations show a threshold line which is independent of the poly(styrene sulfonate) concentration. An additional re-entrant phase, at considerably higher cation content than those of the threshold lines, is observed with Al3+ cations but not with Ba2+ cations. The threshold line and the re-entrant phase boundary form parts of the liquid-liquid phase boundary observed at the limit of low polymer concentration. The dimensions of the polyelectrolyte chains shrink considerably while approaching the respective threshold lines on increase of the Al3+ and Ba2+ cation content. However, subtle differences occur between the morphological transformation induced by Al3+ and Ba2+. Most strikingly, coils decorated with Al3+ respond very differently to temperature variations than coils decorated with Ba2+ do. As the temperature increases, the poly(styrene sulfonate) chains decrease their size in the presence of Al3+ cations but increase in size in the presence of Ba2+ cations.

  12. Studies on volumetric properties of some saccharides in aqueous potassium chloride solutions over temperature range (288.15 to 318.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Banipal, Parampaul K. [Department of Chemistry, Guru Nanak Dev University, Amritsar 143 005 (India)], E-mail: pkbanipal@yahoo.com; Chahal, Amanpreet K. [Department of Chemistry, Guru Nanak Dev University, Amritsar 143 005 (India); Banipal, Tarlok S. [Department of Applied Chemistry, Guru Nanak Dev University, Amritsar 143 005 (India)

    2009-04-15

    The standard partial molar volumes, V{sub 2}{sup {infinity}} at infinite dilution of monosaccharides; D(+)-xylose, D(-)-arabinose, D(-)-ribose, D(+)-mannose, D(+)-galactose, D(-)-fructose and D(+)-glucose, disaccharides; D(+)-melibiose, D(+)-cellobiose, D(+)-maltose monohydrate, D(+)-trehalose dihydrate, D(+)-lactose monohydrate and sucrose, trisaccharide; D(+)-raffinose pentahydrate, methylglycosides; {alpha}-methyl-D(+)-glucoside, methyl-{alpha}-D-xylopyranoside and methyl-{beta}-D-xylopyranoside have been determined in water and in aqueous solutions of potassium chloride (0.5, 1.0, 2.0, and 3.0) mol . kg{sup -1} at T = (288.15, 298.15, 308.15, and 318.15) K from density measurements employing a vibrating-tube densimeter. These results have been utilized to determine the corresponding standard partial molar volumes of transfer, {delta}{sub t}V{sub 2}{sup {infinity}} for the transfer of various saccharides from water to aqueous potassium chloride solutions. The standard transfer volumes have been found to be positive (except for {alpha}- and {beta}-methyl xylopyranosides in 0.5 mol . kg{sup -1} solutions of potassium chloride) whose magnitude increase with the concentration of potassium chloride as well as temperature for all the saccharides. Partial molar expansion coefficients, ({partial_derivative}V{sub 2}{sup {infinity}}/{partial_derivative}T){sub p} and the second derivative ({partial_derivative}{sup 2}V{sub 2}{sup {infinity}}/{partial_derivative}T{sup 2}){sub p} values have been estimated. Pair and higher order volumetric interaction coefficients have also been calculated from {delta}{sub t}V{sub 2}{sup {infinity}} by using the McMillan-Mayer theory. These parameters have been discussed in terms of the solute-cosolute interactions and are used to understand various mixing effects due to these interactions. The effect of substitution of -OH by glycosidic group, -OCH{sub 3} is also discussed. Attempt has also been made to discuss the stereochemical effects

  13. Density, speed of sound, viscosity and refractive index properties of aqueous solutions of vitamins B1.HCl and B6.HCl at temperatures (278.15, 288.15, and 298.15) K

    International Nuclear Information System (INIS)

    Dhondge, Sudhakar S.; Deshmukh, Dinesh W.; Paliwal, Lalitmohan J.

    2013-01-01

    Highlights: ► Study of aqueous solutions of vitamins B 1 .HCl and B 6 .HCl at different temperatures has been presented. ► These are important vitamins. ► Different interactions among solute and solvents have been investigated. ► The results are interpreted in terms of water structure making and breaking effects due to cations. -- Abstract: The experimental values of density (ρ), speed of sound (u), absolute viscosity (η) and refractive index (n D ) properties are reported for aqueous solutions of thiamine hydrochloride (vitamin B 1 .HCl) and pyridoxine hydrochloride (vitamin B 6 .HCl) within the concentration range (0.01 to 0.55) mol ⋅ kg −1 at three different temperatures, viz. T/K = 278.15, 288.15, and 298.15. Using experimental data, different derived parameters such as the apparent molar volume of solute (ϕ V ), isentropic compressibility of solution (β S ), apparent molar isentropic compressibility of solute (ϕ KS ) and relative viscosity of solution (η r ) have been computed. The limiting values of apparent molar volume (ϕ V 0 ) and apparent molar isentropic compressibility (ϕ KS 0 ) have been obtained. The limiting apparent molar expansivity (ϕ E 0 ) of solute, coefficient of thermal expansion (α ∗ ) and hydration numbers (n h ) of above vitamins in the aqueous medium have also been estimated. The experimental values of relative viscosity are used to calculate the Jones–Dole equation viscosity A and B coefficients for the hydrochlorides. The temperature coefficients of B i.e. (dB/dT) for these solutes have been used to study water structure making and breaking effects due to cations. Further, a discussion is made on the basis of solute–solute and solute–solvent interactions

  14. Fabrication of Nb3Al superconducting wires by utilizing the mechanically alloyed Nb(Al)ss supersaturated solid-solution with low-temperature annealing

    International Nuclear Information System (INIS)

    Pan, X.F.; Yan, G.; Qi, M.; Cui, L.J.; Chen, Y.L.; Zhao, Y.; Li, C.S.; Liu, X.H.; Feng, Y.; Zhang, P.X.; Liu, H.J.

    2014-01-01

    Highlights: • This paper reported superconducting properties of the powder-in-tube Nb 3 Al wires. • The Nb 3 Al wires were made by using Nb(Al) ss supersaturated solid solution powders. • The Cu-matrix Nb 3 Al superconducting wires have been successfully fabricated. • The transport J c of Nb 3 Al wires at 4.2 K, 10 T is up to 12,700 A/cm 2 . - Abstract: High-performance Nb 3 Al superconducting wire is a promising candidate to the application of high-field magnets. However, due to the production problem of km-grade wires that are free from low magnetic field instability, the Nb 3 Al wires made by rapid heating, quenching and transformation (RHQT) are still not available to the large-scale engineering application. In this paper, we reported the properties of the in situ powder-in-tube (PIT) Nb 3 Al superconducting wires, which were made by using the mechanically alloyed Nb(Al) ss supersaturated solid solution, as well as the low temperature heat-treatment at 800 °C for 10 h. The results show that Nb 3 Al superconductors in this method possess very fine grains and well superconducting properties, though a little of Nb 2 Al and Nb impurities still keep being existence at present work. At the Nb 3 Al with a nominal 26 at.% Al content, the onset T c reaches 15.8 K. Furthermore, a series of Nb 3 Al wires and tapes with various sizes have been fabricated; for the 1.0 mm-diameter wire, the J c at 4.2 K, 10 T and 14 T have achieved 12,700 and 6900 A/cm 2 , respectively. This work suggests it is possible to develop high-performance Cu-matrix Nb 3 Al superconducting wires by directly using the Nb(Al) ss supersaturated solid-solution without the complex RHQT heat-treatment process

  15. Effect of the borax mass and pre-spray medium temperature on droplet size and velocity vector distributions of intermittently sprayed starchy solutions.

    Science.gov (United States)

    Naz, Muhammad Yasin; Sulaiman, Shaharin Anwar; Ariwahjoedi, Bambang

    2015-02-07

    Spray coating technology has demonstrated great potential in the slow release fertilizers industry. The better understanding of the key spray parameters benefits both the environment and low cost coating processes. The use of starch based materials to coat the slow release fertilizers is a new development. However, the hydraulic spray jet breakup of the non-Newtonian starchy solutions is a complex phenomenon and very little known. The aim of this research was to study the axial and radial distributions of the Sauter Mean Diameter (SMD) and velocity vectors in pulsing spray patterns of native and modified tapioca starch solutions. To meet the objective, high speed imaging and Phase Doppler Anemometry (PDA) techniques were employed to characterize the four compositions of the starch-urea-borax complex namely S0, S1, S2 and S3. The unheated solutions exhibited very high viscosities ranging from 2035 to 3030 cP. No jet breakup was seen at any stage of the nozzle operation at an injection pressure of 1-5 bar. However, at 80 °C temperature and 5 bar pressure, the viscosity was reduced to 455 to 638 cP and dense spray patterns emerged from the nozzle obscuring the PDA signals. The axial size distribution revealed a significant decrease in SMD along the spray centreline. The smallest axial SMD (51 to 79 μm) was noticed in S0 spray followed by S1, S2 and S3. Unlikely, the radial SMD in S0 spray did not vary significantly at any stage of the spray injection. This trend was attributed to the continuous growth of the surface wave instabilities on the native starch sheet. However, SMD obtained with S1, S2 and S3 varied appreciably along the radial direction. The mean velocity vector profiles followed the non-Gaussian distribution. The constant vector distributions were seen in the near nozzle regions, where the spray was in the phase of development. In far regions, the velocity vectors were poly-dispersed and a series of ups and downs were seen in the respective radial

  16. Fabrication of Nb{sub 3}Al superconducting wires by utilizing the mechanically alloyed Nb(Al){sub ss} supersaturated solid-solution with low-temperature annealing

    Energy Technology Data Exchange (ETDEWEB)

    Pan, X.F. [National Engineering Laboratory for Superconducting Material, Western Superconducting Technologies (WST) Co., Ltd., Xi’an 710018 (China); Superconducting Materials Center, Northwest Institute for Nonferrous Metal Research, Xi’an 710016 (China); Yan, G., E-mail: gyan@c-nin.com [National Engineering Laboratory for Superconducting Material, Western Superconducting Technologies (WST) Co., Ltd., Xi’an 710018 (China); Superconducting Materials Center, Northwest Institute for Nonferrous Metal Research, Xi’an 710016 (China); Qi, M. [Superconducting Materials Center, Northwest Institute for Nonferrous Metal Research, Xi’an 710016 (China); Cui, L.J. [National Engineering Laboratory for Superconducting Material, Western Superconducting Technologies (WST) Co., Ltd., Xi’an 710018 (China); Chen, Y.L.; Zhao, Y. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of China), Superconductivity and New Energy R and D Center, Southwest Jiaotong University, Chengdu 610031 (China); Li, C.S. [Superconducting Materials Center, Northwest Institute for Nonferrous Metal Research, Xi’an 710016 (China); Liu, X.H. [National Engineering Laboratory for Superconducting Material, Western Superconducting Technologies (WST) Co., Ltd., Xi’an 710018 (China); Feng, Y.; Zhang, P.X. [National Engineering Laboratory for Superconducting Material, Western Superconducting Technologies (WST) Co., Ltd., Xi’an 710018 (China); Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of China), Superconductivity and New Energy R and D Center, Southwest Jiaotong University, Chengdu 610031 (China); Liu, H.J. [Institute of Plasma Physics, Chinese Academy of Sciences (CAS), Hefei 230031 (China); and others

    2014-07-15

    Highlights: • This paper reported superconducting properties of the powder-in-tube Nb{sub 3}Al wires. • The Nb{sub 3}Al wires were made by using Nb(Al){sub ss} supersaturated solid solution powders. • The Cu-matrix Nb{sub 3}Al superconducting wires have been successfully fabricated. • The transport J{sub c} of Nb{sub 3}Al wires at 4.2 K, 10 T is up to 12,700 A/cm{sup 2}. - Abstract: High-performance Nb{sub 3}Al superconducting wire is a promising candidate to the application of high-field magnets. However, due to the production problem of km-grade wires that are free from low magnetic field instability, the Nb{sub 3}Al wires made by rapid heating, quenching and transformation (RHQT) are still not available to the large-scale engineering application. In this paper, we reported the properties of the in situ powder-in-tube (PIT) Nb{sub 3}Al superconducting wires, which were made by using the mechanically alloyed Nb(Al){sub ss} supersaturated solid solution, as well as the low temperature heat-treatment at 800 °C for 10 h. The results show that Nb{sub 3}Al superconductors in this method possess very fine grains and well superconducting properties, though a little of Nb{sub 2}Al and Nb impurities still keep being existence at present work. At the Nb{sub 3}Al with a nominal 26 at.% Al content, the onset T{sub c} reaches 15.8 K. Furthermore, a series of Nb{sub 3}Al wires and tapes with various sizes have been fabricated; for the 1.0 mm-diameter wire, the J{sub c} at 4.2 K, 10 T and 14 T have achieved 12,700 and 6900 A/cm{sup 2}, respectively. This work suggests it is possible to develop high-performance Cu-matrix Nb{sub 3}Al superconducting wires by directly using the Nb(Al){sub ss} supersaturated solid-solution without the complex RHQT heat-treatment process.

  17. Seven harmonic susceptibility in oxygen and hydrogen loading of sintered YBCO by {mu}s pulsed electrolysis in an aqueous solution at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Tripodi, P.; Di Gioacchino, D.; Celani, F. [Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati

    1996-09-01

    The complex AC susceptibility of high T{sub c} superconducting materials has been described in terms of the first seven harmonic component of Fourier series. Has been measured the {chi}{sub n} (n=1,7) of sintered YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) bulk oxygen and hydrogen loaded samples versus amplitude and frequency of AC magnetic field at fixed temperature. The sample have been loaded by {mu}s current pulses electrolysis in an aqueous solution (0.3N LiOH+H{sub 2}O) at room temperature. In addition to the simplicity of the experimental setup, this procedure allows to obtain extremely high equivalent hydrogen/oxygen gas pressure on the surface of the electrodes. The YBCO electrode is polarized by short pulse width (0.5-10 {mu}s) and high power (120 W) peaks with a variable repetition rate (0.1-10000 Hz). The pulses are obtained by an home.made pulse generator. The difference in the behavior of the susceptibilities harmonic component between the deficiency and oxygen or hydrogen loaded samples give us the possibility to connect the susceptibilities with variations of the flux pinning in respect to normal losses in the superconducting materials. The loading can be a good probe to have information on the mechanism of the processes that sustain the critical current density Jc in this situation these affects appear strongly dependent on the loading conditions. By comparison of this measurements has been observed drastic change in behavior of susceptibility.

  18. Measurement of Thermal Conductivities of Two Cryoprotective Agent Solutions for Vitreous Cryopreservation of Organs at the Temperature Range of 77 K-300 K Using a Thermal Sensor Made of Microscale Enamel Copper Wire.

    Science.gov (United States)

    Li, Yufang; Zhao, Gang; Hossain, S M Chapal; Panhwar, Fazil; Sun, Wenyu; Kong, Fei; Zang, Chuanbao; Jiang, Zhendong

    2017-06-01

    Biobanking of organs by cryopreservation is an enabling technology for organ transplantation. Compared with the conventional slow freezing method, vitreous cryopreservation has been regarded to be a more promising approach for long-term storage of organs. The major challenges to vitrification are devitrification and recrystallization during the warming process, and high concentrations of cryoprotective agents (CPAs) induced metabolic and osmotic injuries. For a theoretical model based optimization of vitrification, thermal properties of CPA solutions are indispensable. In this study, the thermal conductivities of M22 and vitrification solution containing ethylene glycol and dimethyl sulfoxide (two commonly used vitrification solutions) were measured using a self-made microscaled hot probe with enameled copper wire at the temperature range of 77 K-300 K. The data obtained by this study will further enrich knowledge of the thermal properties for CPA solutions at low temperatures, as is of primary importance for optimization of vitrification.

  19. Soliton solutions and chaotic motion of the extended Zakharov-Kuznetsov equations in a magnetized two-ion-temperature dusty plasma

    Energy Technology Data Exchange (ETDEWEB)

    Zhen, Hui-Ling; Tian, Bo, E-mail: tian-bupt@163.com; Wang, Yu-Feng; Sun, Wen-Rong; Liu, Li-Cai [State Key Laboratory of Information Photonics and Optical Communications, and School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China)

    2014-07-15

    The extended Zakharov-Kuznetsov (eZK) equation for the magnetized two-ion-temperature dusty plasma is studied in this paper. With the help of Hirota method, bilinear forms and N-soliton solutions are given, and soliton propagation is graphically analyzed. We find that the soliton amplitude is positively related to the nonlinear coefficient A, while inversely related to the dispersion coefficients B and C. We obtain that the soliton amplitude will increase with the mass of the jth dust grain and the average charge number residing on the dust grain decreased, but the soliton amplitude will increase with the equilibrium number density of the jth dust grain increased. Upon the introduction of the periodic external forcing term, both the weak and developed chaotic motions can occur. Difference between the two chaotic motions roots in the inequality between the nonlinear coefficient l{sub 2} and perturbed term h{sub 1}. The developed chaos can be weakened with B or C decreased and A increased. Periodic motion of the perturbed eZK equation can be observed when there is a balance between l{sub 2} and h{sub 1}.

  20. Removal of radiocobalt from aqueous solutions by kaolinite affected by solid content, pH, ionic strength, contact time and temperature

    International Nuclear Information System (INIS)

    Kan Li; Zhengjie Liu; Lei Chen; Yunhui Dong; Jun Hu; Chinese Academy of Sciences, Hefei

    2013-01-01

    The kaolinite sample was characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray powder diffraction, and was applied as adsorbent for the removal of radiocobalt ions from radioactive wastewater. The results demonstrated that the sorption of Co(II) was strongly dependent on pH and ionic strength at low pH values, and independent of pH and ionic strength at high pH values. The sorption of Co(II) was dominated by outer-sphere surface complexation or ion exchange at low pH values, whereas inner-sphere surface complexation was the main sorption mechanism at high pH values. The sorption isotherms were well described by Langmuir, Freundlich and Dubinin-Radushkevich models. The thermodynamic parameters (i.e., ΔGdeg, ΔSdeg, ΔHdeg) calculated from the temperature-dependent sorption isotherms indicated that the sorption of Co(II) on kaolinite was an endothermic and spontaneous process. The results of high sorption capacity of kaolinite suggested that the kaolinite sample was a suitable material for the preconcentration of Co(II) from large volumes of aqueous solutions and as backfill materials in nuclear waste management. (author)

  1. Low-temperature fabrication of an HfO2 passivation layer for amorphous indium-gallium-zinc oxide thin film transistors using a solution process.

    Science.gov (United States)

    Hong, Seonghwan; Park, Sung Pyo; Kim, Yeong-Gyu; Kang, Byung Ha; Na, Jae Won; Kim, Hyun Jae

    2017-11-24

    We report low-temperature solution processing of hafnium oxide (HfO 2 ) passivation layers for amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs). At 150 °C, the hafnium chloride (HfCl 4 ) precursor readily hydrolyzed in deionized (DI) water and transformed into an HfO 2 film. The fabricated HfO 2 passivation layer prevented any interaction between the back surface of an a-IGZO TFT and ambient gas. Moreover, diffused Hf 4+ in the back-channel layer of the a-IGZO TFT reduced the oxygen vacancy, which is the origin of the electrical instability in a-IGZO TFTs. Consequently, the a-IGZO TFT with the HfO 2 passivation layer exhibited improved stability, showing a decrease in the threshold voltage shift from 4.83 to 1.68 V under a positive bias stress test conducted over 10,000 s.

  2. Solution-chemical route to generalized synthesis of metal germanate nanowires with room-temperature, light-driven hydrogenation activity of CO2 into renewable hydrocarbon fuels.

    Science.gov (United States)

    Liu, Qi; Zhou, Yong; Tu, Wenguang; Yan, Shicheng; Zou, Zhigang

    2014-01-06

    A facile solution-chemical route was developed for the generalized preparation of a family of highly uniform metal germanate nanowires on a large scale. This route is based on the use of hydrazine monohydrate/H2O as a mixed solvent under solvothermal conditions. Hydrazine has multiple effects on the generation of the nanowires: as an alkali solvent, a coordination agent, and crystal anisotropic growth director. Different-percentage cobalt-doped Cd2Ge2O6 nanowires were also successfully obtained through the addition of Co(OAc)2·4H2O to the initial reaction mixture for future investigation of the magnetic properties of these nanowires. The considerably negative conduction band level of the Cd2Ge2O6 nanowire offers a high driving force for photogenerated electron transfer to CO2 under UV-vis illumination, which facilitates CO2 photocatalytic reduction to a renewable hydrocarbon fuel in the presence of water vapor at room temperature.

  3. Thermodynamic properties of solutions of sodium di-hydrogen phosphate in (1-propanol + water) mixed-solvent media over the temperature range of (283.15 to 303.15) K

    International Nuclear Information System (INIS)

    Sadeghi, Rahmat; Parhizkar, Hana

    2008-01-01

    The apparent molar volume and apparent molar isentropic compressibility of solutions of sodium di-hydrogen phosphate (NaH 2 PO 4 ) in (1-propanol + water) mixed-solvent media with alcohol mass fractions of 0.00, 0.05, 0.10, and 0.15 are reported over the range of temperature (283.15 to 303.15) K at 5 K intervals. The results were fitted to a Redlich-Mayer type equation from which the apparent molar volume and apparent molar isentropic compressibility of the solutions at the infinite dilution were also calculated at the working temperature. The results show a positive transfer volume of NaH 2 PO 4 from an aqueous solution to an aqueous 1-propanol solution. The apparent molar isentropic compressibility of NaH 2 PO 4 in aqueous 1-propanol solutions is negative and it increases with increasing the concentration of NaH 2 PO 4 , 1-propanol, and temperature. Electrical conductivity and refractive index of the solutions are also studied at T = 298.15 K. The effects of the electrolyte concentration and relative permittivity of the medium on the molar conductivity were also investigated

  4. Comparison of inter-diffusion coefficients for Ni/Cu thin films determined from classical heating analysis and linear temperature ramping analysis by means of profile reconstruction and a numerical solution of Fick's law

    International Nuclear Information System (INIS)

    Joubert, H.D.; Terblans, J.J.; Swart, H.C.

    2009-01-01

    Classical inter-diffusion studies assume a constant time of annealing when samples are annealed in a furnace. It is assumed that the sample temperature reaches the annealing temperature immediately after insertion, while the sample temperature immediately drops to room temperature after removal, the annealing time being taken as the time between insertion and removal. Using the above assumption, the diffusion coefficient can be calculated in a number of ways. In reality, the sample temperature does not immediately reach the annealing temperature; instead it rises at a rate governed by several heat transfer mechanisms, depending on the annealing procedure. For short annealing times, the sample temperature may not attain the annealing temperature, while for extended annealing times the sample temperature may reach the annealing temperature only for a fraction of the annealing time. To eliminate the effect of heat transfer mechanisms, a linear temperature ramping regime is proposed. Used in conjunction with a suitable profile reconstructing technique and a numerical solution of Fick's second law, the inter-diffusion parameters obtained from a linear ramping of Ni/Cu thin film samples can be compared to those obtained from calculations performed with the so-called Mixing-Roughness-Information model or any other suitable method used to determine classical diffusion coefficients.

  5. Waterborne Electrospinning of Poly(N-isopropylacrylamide) by Control of Environmental Parameters.

    Science.gov (United States)

    Schoolaert, Ella; Ryckx, Paulien; Geltmeyer, Jozefien; Maji, Samarendra; Van Steenberge, Paul H M; D'hooge, Dagmar R; Hoogenboom, Richard; De Clerck, Karen

    2017-07-19

    With increasing toxicity and environmental concerns, electrospinning from water, i.e., waterborne electrospinning, is crucial to further exploit the resulting nanofiber potential. Most water-soluble polymers have the inherent limitation of resulting in water-soluble nanofibers, and a tedious chemical cross-linking step is required to reach stable nanofibers. An interesting alternative route is the use of thermoresponsive polymers, such as poly(N-isopropylacrylamide) (PNIPAM), as they are water-soluble beneath their lower critical solution temperature (LCST) allowing low-temperature electrospinning while the obtained nanofibers are water-stable above the LCST. Moreover, PNIPAM nanofibers show major potential to many application fields, including biomedicine, as they combine the well-known on-off switching behavior of PNIPAM, thanks to its LCST, with the unique properties of nanofibers. In the present work, based on dedicated turbidity and rheological measurements, optimal combinations of polymer concentration, environmental temperature, and relative humidity are identified allowing, for the first time, the production of continuous, bead-free PNIPAM nanofibers electrospun from water. More specifically, PNIPAM gelation was found to occur well below its LCST at higher polymer concentrations leading to a temperature regime where the viscosity significantly increases without compromising the polymer solubility. This opens up the ecological, water-based production of uniform PNIPAM nanofibers that are stable in water at temperatures above PNIPAM's LCST, making them suitable for various applications, including drug delivery and switchable cell culture substrates.

  6. Solid Adsorbents for Low-Temperature CO{sub 2} Capture with Low-Energy Penalties Leading to More Effective Integrated Solutions for Power Generation and Industrial Processes

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Nannan [Chinese Academy of Sciences Key Laboratory of Low-Carbon Conversion Science and Engineering, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai (China); Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham (United Kingdom); Tang, Zhiyong; Wei, Wei [Chinese Academy of Sciences Key Laboratory of Low-Carbon Conversion Science and Engineering, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai (China); Snape, Colin Edward [Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham (United Kingdom); Sun, Yuhan, E-mail: sunyh@sari.ac.cn [Chinese Academy of Sciences Key Laboratory of Low-Carbon Conversion Science and Engineering, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai (China)

    2015-03-09

    CO{sub 2} capture represents the key technology for CO{sub 2} reduction within the framework of CO{sub 2} capture, utilization, and storage (CCUS). In fact, the implementation of CO{sub 2} capture extends far beyond CCUS since it will link the CO{sub 2} emission and recycling sectors, and when renewables are used to provide necessary energy input, CO{s