OPTICAL PROPERTIES OF CARBAMIDE AQUEOUS SOLUTIONS

Directory of Open Access Journals (Sweden)

E. V. Avramenko

2016-03-01

Full Text Available Subject of Research. The paper presents the results of measurements of refractometric properties (refractive index n, its temperature factor dn/dt and the ultraviolet spectral absorption in carbonic acid diamide aqueous solutions (carbamide depending on solid residue mass fraction md = 0-50 % and on temperaturet = 10-70 °C.Method of Research. Laboratory methods ofliquid-phase medium refractometry and ultraviolet spectrophotometry were applied for the research. We carried out computational modeling of electronic states spectrum for the carbonic acid diamide molecule and theoretical calculation of the fundamental electronic absorption of the molecule in the ultraviolet wavelenght region.Main Results. We have established that the solution concentration md has a nonlinear character and may be represented by the quadratic polynomial with the error Δn= ± 0,0005. We have shown the refractive indexdependence on temperature n(t changes in linear fashion att = 10-70 °C.At that, the inclination of lines n(t increases at the increase of md; so, the temperature factor dn/dt may be approximated by the quadratic polynomial. Transmission spectra of solutions in the spectral region λ= 225-760 nm have no special features except for the sharp edge in the short-wavelength region; the fundamental electronic absorptionis responsible for it. We have established that dispersion dependences of the refraction index n(λ;md in aqueous solutions of carbamide at λ= 360-760 nm and at md = 0-50 % may be calculated with the satisfactory error without additional adjustable parameters from the ultraviolet absorption data in terms of the one-dimentional oscillator Lorentz model.PracticalRelevance. Representedmeasurements of carbonic acid diamide aqueous solutions optical properties may be applied for the adjustment and calibration of commercial refractometers at processing lines of the AdBlue reagent manufacture for the selective catalytic reduction (SCR of motor transport

Surface and conductivity properties of imidazoles solutions

International Nuclear Information System (INIS)

Rogalski, Marek; Domanska, Urszula; Czyrny, Dagmara; Dyczko, Dagmara

2002-01-01

The surface tension, σ, of the solutions of benzimidazole, 2-phenylimidazole and 2,4,5-triphenylimidazole in water, or water + 10 mol% of acetonitrile, or in other solvents as well as the solubilities and conductivity of benzimidazole and 2-phenylimidazole in water in function of concentration at 298.15 K were measured. The enthalpy of fusion, or solid-solid phase transition and the melting temperatures were determined for the substances under study by the scanning calorimetry (DSC). These solutions exhibit, in a wide range of concentrations, the normal linear, or parabolic decreasing dependencies and the maximum of surface tension at very low concentrations and show the S-shaped dependencies, being in function of the initial sample, never reported before. The results were confirmed by the conductivity measurements. The results were interpreted in terms of the changing structure of the interface. It was concluded that the observed phenomena were caused by an induced nucleation of benzimidazole, 2-phenylimidazole and especially by 2,4,5-triphenylimidazole by columnar discotic structures due to the initial concentration. The surface properties of these solutions reflect the interactions of hydrophobic parts of the guest molecules adsorbed at the interface, as a result of the hydrogen bonded structure of the solution

Fluctuation Solution Theory Properties from Molecular Simulation

DEFF Research Database (Denmark)

Abildskov, Jens; Wedberg, R.; O’Connell, John P.

2013-01-01

The thermodynamic properties obtained in the Fluctuation Solution Theory are based on spatial integrals of molecular TCFs between component pairs in the mixture. Molecular simulation, via either MD or MC calculations, can yield these correlation functions for model inter- and intramolecular...

Some Properties of Solutions for the Sixth-Order Cahn-Hilliard-Type Equation

Directory of Open Access Journals (Sweden)

Zhao Wang

2012-01-01

Full Text Available We study the initial boundary value problem for a sixth-order Cahn-Hilliard-type equation which describes the separation properties of oil-water mixtures, when a substance enforcing the mixing of the phases is added. We show that the solutions might not be classical globally. In other words, in some cases, the classical solutions exist globally, while in some other cases, such solutions blow up at a finite time. We also discuss the existence of global attractor.

Composite Properties of Polyimide Resins Made From "Salt-Like" Solution Precursors

Science.gov (United States)

Cano, Roberto J.; Weiser, Erik S.; SaintClair, Terry L.; Echigo, Yoshiaki; Kaneshiro, Hisayasu

1997-01-01

Recent work in high temperature materials at NASA Langley Research Center (LaRC (trademark)) have led to the development of new polyimide resin systems with very attractive properties. The majority of the work done with these resin systems has concentrated on determining engineering mechanical properties of composites prepared from a poly(amide acid) precursor. Three NASA Langley-developed polyimide matrix resins, LaRC (trademark) -IA, LaRC (trademark) -IAX, and LaRC (trademark) -8515, were produced via a salt-like process developed by Unitika Ltd. The 'salt-like' solutions (sixty-five percent solids in NMP) were prepregged onto Hexcel IM7 carbon fiber using the NASA LaRC Multipurpose Tape Machine. Process parameters were determined and composite panels fabricated. Mechanical properties are presented for these three intermediate modulus carbon fiber/polyimide matrix composites and compared to existing data on the same polyimide resin systems and IM7 carbon fiber manufactured via poly(amide acid) solutions (thirty-five percent solids in NMP). This work studies the effects of varying the synthetic route on the processing and mechanical properties of polyimide composites.

Properties of solutions of Bloch-type equations for the paraelectric phase of KDP

Energy Technology Data Exchange (ETDEWEB)

Glowacki, M; Paszkiewicz, T [Wroclaw Univ. (Poland). Inst. Fyziki Teoretycznej

1979-10-01

Exact solutions for two sets of Bloch-like equations describing the paraelectric phase of the model of KDP were studied. The general properties of both solutions are the same. However, in numerical calculations they differ significantly. A modification of the decay law connected with the soft mode frequency fluctuations is considered.

Characterization of Skeletonema costatum Intracellular Organic Matter and Study of Nanomechanical Properties under Different Solution Conditions

KAUST Repository

Gutierrez, Leonardo

2016-06-17

In the current investigation, a rigorous characterization of the high molecular weight (HMW) compounds of Skeletonema costatum (SKC) intracellular organic matter (IOM), including nanomechanical properties, was conducted. HMW SKC-IOM was characterized as a mixture of polysaccharides, proteins, and lipids. Atomic force microscopy (AFM) provided crucial information of this isolate at a nanoscale resolution. HMW SKC-IOM showed highly responsive to solution chemistry: fully extended chains at low ionic strength, and compressing structures with increasing electrolyte concentration in solution. Interestingly, two regions of different nanomechanical properties were observed: (a) Region #1: located farther from the substrate and showing extended polymeric chains, and (b) Region #2: located <10 nm above the substrate and presenting compressed structures. The polymer length, polymer grafting density, and compressibility of these two regions were highly influenced by solution conditions. Results suggest that steric interactions originating from HMW SKC-IOM polymeric structure would be a dominant interacting mechanism with surfaces. The current investigation has successfully applied models of polymer physics to describe the complex HMW SKC-IOM structural conformation at different solution conditions. The detailed methodology presented provides a tool to characterize and understand biopolymers interactions with surfaces, including filtration membranes, and can be extended to other environmentally relevant organic compounds.

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.

Effect of C content on the mechanical properties of solution treated as-cast ASTM F-75 alloys.

Science.gov (United States)

Herrera, M; Espinoza, A; Méndez, J; Castro, M; López, J; Rendón, J

2005-07-01

The mechanical properties of solution treated ASTM F-75 alloys with various carbon contents have been studied. Alloys cast under the same conditions were subjected to solution treatment for several periods and then their tensile properties were evaluated. In the as-cast conditions, the alloys exhibited higher strength values with increasing carbon content whereas their ductility was not significantly affected. For the solution treated alloys, the variation of the strength was characterized by a progressive increase for short treatment times until a maximum value was achieved, which was followed by a diminution in this property for longer treatment times. This behavior was more accentuated for the case of the alloys with medium carbon contents, which also exhibited the highest values of strength. Furthermore, the alloy's ductility was enhanced progressively with increasing solution treatment time. This improvement in ductility was significantly higher for the medium carbon alloys compared with the rest of the studied alloys. Thus, high and low carbon contents in solution treated ASTM F-75 alloys did not produced sufficiently high tensile properties.

Asymptotic properties of spherically symmetric, regular and static solutions to Yang-Mills equations

International Nuclear Information System (INIS)

Cronstrom, C.

1987-01-01

In this paper the author discusses the asymptotic properties of solutions to Yang-Mills equations with the gauge group SU(2), for spherically symmetric, regular and static potentials. It is known, that the pure Yang-Mills equations cannot have nontrivial regular solutions which vanish rapidly at space infinity (socalled finite energy solutions). So, if regular solutions exist, they must have non-trivial asymptotic properties. However, if the asymptotic behaviour of the solutions is non-trivial, then the fact must be explicitly taken into account in constructing the proper action (and energy) for the theory. The elucidation of the appropriate surface correction to the Yang-Mills action (and hence the energy-momentum tensor density) is one of the main motivations behind the present study. In this paper the author restricts to the asymptotic behaviour of the static solutions. It is shown that this asymptotic behaviour is such that surface corrections (at space-infinity) are needed in order to obtain a well-defined (classical) theory. This is of relevance in formulating a quantum Yang-Mills theory

Calorimetric Studies on Thermal Properties of Nano-Cryoprotectant Solutions during Vitrification.

Science.gov (United States)

Xu, H F; Hao, B T; Liu, L J; Tang, L L; Liu, B L

BACKGROUND: Vitrification, the ice-free cryopreservation, develops rapidly and can become an ideal method for long-term preservation of cells and tissues. But up to now it is not practical for samples with large size because of the ultra-rapid cooling rate required. It has been reported that nanoparticles improve heat conductivity of solutions. In this study, Hydroxyapatite (HA) nanoparticles（20, 40 or 60nm）at 0.1 %, 0.5 % or 1 % (w/w) were added into glycerol solutions. Glass transition temperature and devitrification temperature of aqueous glycerol solutions with/without HA nanoparticles were measured by a differential scanning calorimeter(DSC) at a cooling rate of 150 degree C/min and a warming rate of 10 degree C/ min. Glass-transition temperatures and devitrification temperatures of glycerol aqueous solutions increased after the incorporation of HA nanoparticles. In the study using slow cooling rate of 10 degree C/min and warming rate of 5 degree C/min, the fraction of unfrozen water in the 50 % (w/w) glycerol solution increases steadily with the addition of HA nanoparticles. The findings have significant implications for biomaterial cryopreservation.

Properties of meromorphic solutions to certain differential-difference equations

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Xiaoguang Qi

2013-06-01

Full Text Available We consider the properties of meromorphic solutions to certain type of non-linear difference equations. Also we show the existence of meromorphic solutions with finite order for differential-difference equations related to the Fermat type functional equation. This article extends earlier results by Liu et al [12].

Effect of different soil washing solutions on bioavailability of residual arsenic in soils and soil properties.

Science.gov (United States)

Im, Jinwoo; Yang, Kyung; Jho, Eun Hea; Nam, Kyoungphile

2015-11-01

The effect of soil washing used for arsenic (As)-contaminated soil remediation on soil properties and bioavailability of residual As in soil is receiving increasing attention due to increasing interest in conserving soil qualities after remediation. This study investigates the effect of different washing solutions on bioavailability of residual As in soils and soil properties after soil washing. Regardless of washing solutions, the sequential extraction revealed that the residual As concentrations and the amount of readily labile As in soils were reduced after soil washing. However, the bioassay tests showed that the washed soils exhibited ecotoxicological effects - lower seed germination, shoot growth, and enzyme activities - and this could largely be attributed to the acidic pH and/or excessive nutrient contents of the washed soils depending on washing solutions. Overall, this study showed that treated soils having lower levels of contaminants could still exhibit toxic effects due to changes in soil properties, which highly depended on washing solutions. This study also emphasizes that data on the As concentrations, the soil properties, and the ecotoxicological effects are necessary to properly manage the washed soils for reuses. The results of this study can, thus, be utilized to select proper post-treatment techniques for the washed soils. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of monohydric alcohols on structural properties of macromolecular solutions

International Nuclear Information System (INIS)

Giordano, R.; Wanderlingh, F.; Cordone, L.; Cupane, A.

1983-01-01

A report on the effects of monohydric alcohols on the thixotropic properties of a 1% (by weight) BSA solution is given. The presence of alcohols in the solution medium, even in a very small amount, weakens the structure responsible for the thixotropic properties: this effect increases with increasing alcohol concentration and alkyl group size. Indirect evidence relating the observed effects to the alteration, in the presence of alcohol, of protein-solvent hydrophobic interactions is also presented

Effects of solution treatment on mechanical properties and corrosion resistance of 4A duplex stainless steel

Energy Technology Data Exchange (ETDEWEB)

Lu, Panpan; Wang, Aiqin; Wang, Wenyan [Henan Univ. of Science and Technology, Luoyang (China). School of Material Science and Engineering; Xie, Jingpei [Henan Univ. of Science and Technology, Luoyang (China). Collaborative Innovation Center of Nonferrous Metals

2018-02-15

In this study, 4A duplex stainless steels were prepared via remelting in an intermediate frequency furnace and subsequently solution treated at different temperatures. The effects of solution treatment on the mechanical properties and corrosion resistance of 4A duplex stainless steel were investigated. Microstructures were characterized via optical microscopy and scanning electron microscopy. The mechanical properties were evaluated via hardness test, tensile test, and impact test experiments. The point corrosion resistance was studied via chemical immersion and potentiodynamic anodic polarization. The results showed that with increasing solution temperature in the range of 1223 - 1423 K, the tensile strength and hardness first decreased and then increased, and minimum values were obtained at 1323 K. The σ phase precipitated at the boundaries of the α/γ phases in samples solution treated at 1223 K, decreasing both impact energy and pitting potential of the experimental steels. When experimental steels were solution treated at 1373 K for 2 h, a suitable volume fraction of α/γ was uniformly distributed throughout the microstructure, and the steels exhibited optimal mechanical properties and pitting corrosion resistance.

Root-induced Changes in the Rhizosphere of Extreme High Yield Tropical Rice: 2. Soil Solution Chemical Properties

Directory of Open Access Journals (Sweden)

Mitsuru Osaki

2012-09-01

Full Text Available Our previous studies showed that the extreme high yield tropical rice (Padi Panjang produced 3-8 t ha-1 without fertilizers. We also found that the rice yield did not correlate with some soil properties. We thought that it may be due to ability of root in affecting soil properties in the root zone. Therefore, we studied the extent of rice root in affecting the chemical properties of soil solution surrounding the root zone. A homemade rhizobox (14x10x12 cm was used in this experiment. The rhizobox was vertically segmented 2 cm interval using nylon cloth that could be penetrated neither root nor mycorrhiza, but, soil solution was freely passing the cloth. Three soils of different origins (Kuin, Bunipah and Guntung Papuyu were used. The segment in the center was sown with 20 seeds of either Padi Panjang or IR64 rice varieties. After emerging, 10 seedlings were maintained for 5 weeks. At 4 weeks after sowing, some chemical properties of the soil solution were determined. These were ammonium (NH4+, nitrate (NO3-, phosphorus (P and iron (Fe2+ concentrations and pH, electric conductivity (EC and oxidation reduction potential (ORP. In general, the plant root changed solution chemical properties both in- and outside the soil rhizosphere. The patterns of changes were affected by the properties of soil origins. The release of exudates and change in ORP may have been responsible for the changes soil solution chemical properties.

Hydrothermal synthesis of pollucite, analcime and their solid solutions and analysis of their properties

Energy Technology Data Exchange (ETDEWEB)

Jing, Zhenzi, E-mail: zzjing@tongji.edu.cn [Key Laboratory of Advanced Civil Engineering Materials, Ministry of Education, Tongji University, 4800 Cao' an Road, Shanghai 201804 (China); Cai, Kunchuan; Li, Yan; Fan, Junjie; Zhang, Yi; Miao, Jiajun; Chen, Yuqian [Key Laboratory of Advanced Civil Engineering Materials, Ministry of Education, Tongji University, 4800 Cao' an Road, Shanghai 201804 (China); Jin, Fangming [School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)

2017-05-15

Pollucite, as a perfect long-term potential host for radioactive Cs immobilization, barely exists in pure form naturally but in an isomorphism form between pollucite and analcime due to coexistence of Cs and Na. Pollucite could be hydrothermally synthesized with Cs-polluted soil or clay minerals which contain Cs and Na, and it is necessary to study the properties of the synthesis if Cs and Na contained. Pure pollucite, analcime and their solid solutions were hydrothermally synthesized with chemicals, and it was found that the most formed pollucite analcime solid solutions with Cs/(Cs + Na) ratios of 2/6–5/6 had very similar properties in mineral composition, morphology and size, structural water (Cs cations) and coordination environment to pollucite. This also suggests that even coexistence of Cs and Na in nature, pollucite favors to form due to site preference for Cs over Na, which leads to the property and the structure of the most solid solutions similar to that of pollucite. - Highlights: •Pure pollucite barely exists in nature due to coexistence of Cs and Na. •Pollucite, analcime and their solid solutions could be hydrothermally synthesized. •Most formed solid solutions were found to have similar properties to pollucite. •Even coexistence in nature, pollucite favors to form due to site preference for Cs over Na.

Thermodynamic properties of fluids from Fluctuation Solution Theory

International Nuclear Information System (INIS)

O'Connell, J.P.

1990-01-01

Fluctuation Theory develops exact relations between integrals of molecular correlation functions and concentration derivatives of pressure and chemical potential. These quantities can be usefully correlated, particularly for mechanical and thermal properties of pure and mixed dense fluids and for activities of strongly nonideal liquid solutions. The expressions yield unique formulae for the desirable thermodynamic properties of activity and density. The molecular theory origins of the flucuation properties, their behavior for systems of technical interest and some of their successful correlations will be described. Suggestions for fruitful directions will be suggested

Rheological study of chitosan in solution

International Nuclear Information System (INIS)

Silva, Italo Guimaraes Medeiros da; Alves, Keila dos Santos; Balaban, Rosangela de Carvalho

2009-01-01

Chitosan is an abundant biopolymer with remarkable physicochemical and biological properties, usually employed in a wide range of applications. It acts as a cationic polyelectrolyte in aqueous acid solutions, leading to unique characteristics. In this work, chitosan was characterized by 1 H NMR and its rheological behavior were studied as function of chitosan sample, shear rate, polymer concentration, ionic strength, time and temperature. In order to calculate rheological parameters and to understand the macromolecular dynamic in solution, the Otswald-de Waele model was fitted. (author)

Zwitterionic polyacrylamides: synthesis, study of their properties in aqueous solution, study of their adsorption on clay particles; Derives zwitterioniques du polyacrylamide. Synthese et etude des proprietes en solution aqueuse et de l'adsorption sur argile

Energy Technology Data Exchange (ETDEWEB)

Carrette, P.L.

1998-12-10

Some zwitterionic polyacrylamides have been prepared and studied in aqueous solution. They are neutral polymers, whose charges are on the same lateral group: the positive charge is a quaternary ammonium and the negative charge is a phosphonate or a sulfonate group. Such poly-betaines have a zero net charge on a wide range of pH. They are prepared in salt-free aqueous solution by radical copolymerization of acrylamide with 3-[3-acrylamide-(propyl)dimethyl-ammonio] propane ethyl phosphate or 3-[3-acrylamide-(propyl)dimethyl-ammonio] propane sulfonate. The study has been restricted to copolymers with 1 to 10 % zwitterionic units and weight average molar masses between 1 and 2.10{sup 6} g/mol. The reactivity ratios have been determined. Their properties in solution and their adsorption on clay particles have been compared to the properties of polyacrylamide and partly hydrolyzed polyacrylamide. The use of the later polymers in petroleum industry is limited by the decrease of viscosity in presence of electrolytes, the precipitation with multi-valent cations and an important sensibility to the hydrolysis at basic pH and/or at high temperature. The rheological properties of zwitterionic polymers are controlled by electrostatic attractive forces between charges of opposite signs. Their viscosity increases as a function of ionic strength: the salts screen these attractive forces, increasing in this way the hydrodynamic volume (anti-polyelectrolyte behaviour). At high shear rates, their viscosity decreases less than in the case of usual polyacrylamide. Moreover, their resistance to hydrolysis is better and the precipitation by calcium salts is avoided unlike others charged polymers such as partly hydrolyzed polyacrylamides. Finally, their adsorption on clay particles (montmorillonite) is always twice higher than polyacrylamide adsorption whatever the salinity and the nature of salt (NaCl or KCl). In conclusion, even with small rates the incorporation of zwitterionic units in

Progress of research on the influence of alkaline cation and alkaline solution on bentonite properties

International Nuclear Information System (INIS)

Ye Weimin; Zheng Zhenji; Chen Bao; Chen Yonggui

2011-01-01

Based on the previous laboratory studies and numerical simulation on bentonite in alkaline environments, the effects of alkaline cation and alkaline solution on mineral composition, microstructure, swelling capacity and hydraulic properties of bentonite are emphasized in this paper, temperature, pH values and concentration are discussed as main affecting factors. When bentonite is exposed to alkaline cation or alkaline solution, microstructure of bentonite will be changed due to the dissolution of montmorillonite and the formation of secondary minerals, which results in the decrease of swelling pressure. The amount of the reduction of swelling pressure depends on the concentration of alkaline solution. Temperature, polyvalent cation, salinity and concentration are the main factors affecting hydraulic properties of bentonite under alkaline conditions. Therefore, future research should focus on the mechanism of coupling effects of weak alkaline solutions on the mineral composition, microstructure, swelling capacity and hydraulic properties of bentonite under different temperatures and different pH values. (authors)

Links between soil properties and steady-state solute transport through cultivated topsoil at the field scale

DEFF Research Database (Denmark)

Koestel, J. K.; Nørgaard, Trine; Loung, N. M.

2013-01-01

It is known that solute transport through soil is heterogeneous at all spatial scales. However, little data are available to allow quantification of these heterogeneities at the field scale or larger. In this study, we investigated the spatial patterns of soil properties, hydrologic state variables......, and tracer breakthrough curves (BTCs) at the field scale for the inert solute transport under a steady-state irrigation rate which produced near-saturated conditions. Sixty-five undisturbed soil columns approximately 20 cm in height and diameter were sampled from the loamy topsoil of an agricultural field...... to larger water saturation and the activation of larger macropores. Our study provides further evidence that it should be possible to estimate solute transport properties from soil properties such as soil texture or bulk density. We also demonstrated that estimation approaches established for the column...

Effects of solution treatment on the microstructure and mechanical properties of Al-Cu-Mg-Ag alloy

International Nuclear Information System (INIS)

Liu, Xiao Yan; Pan, Qing Lin; Lu, Zhi Lun; Cao, Su Fang; He, Yun Bin; Li, Wen Bin

2010-01-01

The effects of solution treatment on the microstructure and mechanical properties of Al-Cu-Mg-Ag alloy were studied by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), differential scanning calorimeter (DSC), transmission electron microscopy (TEM) and tensile test, respectively. The results show that the mechanical property increases and then decreases with increasing the solution temperature. And the residual phases are dissolved into the matrix gradually, the number fraction of the precipitation and the size of recrystallized grains increase. Compared to the solution temperature, the solution holding time has less effect on the microstructure and the mechanical properties of Al-Cu-Mg-Ag alloy. The overburnt temperature of Al-Cu-Mg-Ag alloy is 525 o C. The yield strength and the elongation get the best when the alloy is solution treated at 515 o C for 1.5 h, is 504 MPa and 12.2% respectively. The fracture mechanism of the samples is ductile fracture.

Dependence of osmotic pressure on solution properties

International Nuclear Information System (INIS)

Fritz, S.J.

1978-01-01

Hydrostatic pressure, temperature, salt concentration, and the chemical composition of the salt are parameters affecting solution properties. Pressure and temperature have little effect on osmosis, but osmotic pressure variations due to type of dissolved salt may be significant, especially at high concentrations. For a given salt solution, concentration variations cause large differences in osmotic pressure. A representative difference in concentration across a clay layer in a relatively shallow groundwater system might be 100 to 1,000 ppm. When expressed as ppm NaCl, this difference could cause a head difference of 0.8 to 8 meters of water if one of the rock bodies were closed to fluid escape

Morphology, thermal and mechanical properties of PVC/MMT nanocomposites prepared by solution blending and solution blending + melt compounding

DEFF Research Database (Denmark)

Madaleno, Liliana Andreia Oliveira; Schjødt-Thomsen, Jan; Pinto, José Cruz

2010-01-01

Two types of montmorillonite (MMT), natural sodium montmorillonite (Na-MMT) and organically modified montmorillonite (OMMT), in different amounts of 1, 2, 5, 10 and 25 phr (parts per hundred resin), were dispersed in rigid poly (vinyl chloride) by two different methods solution blending...... and solution blending + melt compounding The effects on morphology, thermal and mechanical properties of the PVC/MMT nanocomposites were studied by varying the amount of Na-MMT and OMMT in both methods SEM and XRD analysis revealed that possible intercalated and exfoliated structures were obtained in all...... prepared by solution blending + melt compounding method Experimental values for 1 and 2 phr are larger than the calculated values which directly suggest that the MMT particles are exfoliated (C) 2010 Elsevier Ltd All rights reserved...

ELECTRICAL AND THERMODYNAMIC PROPERTIES OF A COLLAGEN SOLUTION

Directory of Open Access Journals (Sweden)

Jaromír Štancl

2017-06-01

Full Text Available This paper focuses on measurements of the electrical properties, the specific heat capacity and the thermal conductivity of a collagen solution (7.19% mass fraction of native bovine collagen in water. The results of our experiments show that specific electrical conductivity of collagen solution is strongly dependent on temperature. The transition region of collagen to gelatin has been observed from the measured temperature dependence of specific electrical conductivity, and has been confirmed by specific heat capacity measurements by a differential scanning calorimetry.

[The study of antimicrobial properties of silver nanoparticles in the form of a colloidal solution in the matrix of finely dispersed silica].

Science.gov (United States)

Korchak, G I; Surmasheva, E V; Mikhienkova, A I; Nikonova, N A; Romanenko, L I; Oliĭnyk, Z A; Gorval', A K; Rosada, M A

2012-01-01

In the experimental study obtained with chemical method colloid solution of nanoparticles (NPs) of silver (Ag) and a composite on his base in the matrix of finely dispersed silica with particle size of 8-12 nm and NPs concentration in basic solution of 0,0016% (0,016 mg/cm3) were established to exhibit high antimicrobial activity against the test organisms: E. coli, P. aeruginosa, S. Aureus and C. Albicans, which depended on a set of factors. Antibacterial properties of tissue impregnated with Ag-NPs were studied. As stabilizing substances a mixture of surface-active substance sodium dodecyl sulfate and polymer polyvinylpyrrolidone was used Before the beginning of the study effective neutralizer was tailored. Times of preservation of antimicrobial activity of test samples have been established, and also their stability throughout long term of supervision (24 months) has been shown. Effect of organic pollution on antimicrobal activity of the samples has been studied. Based on obtained results the algorithm of the study of antimicrobial properties of nanopreparations has been elaborated.

Characterisation and solution properties of a galactomannan from Bauhinia monandra seeds.

Science.gov (United States)

Nwokocha, Louis M; Senan, Chandra; Williams, Peter A; Yadav, Madhav P

2017-08-01

This study reports on the chemical and physicochemical properties of the polysaccharide isolated from Bauhinia monandra seeds. The seeds were found to contain 17.8% polysaccharide which consisted predominantly of galactose and mannose. The Man/Gal ratio was found to be approximately 4:1and the average molar mass was 2.54×10 5 g/mol. The extracted material was also found to contain a small amount of protein (5.35%). The galactomannan produced highly viscous solution; the viscosity-shear rate profile was best described by the Williamson model. The mechanical spectrum of a 0.5wt% solution showed that G″ was greater than G' over the frequency range employed while at higher concentrations G' became greater than G″ above a critical frequency. The solutions obeyed the Cox-Merz rule at low concentrations, but there was some deviation at higher concentrations. Viscosity measurements were undertaken over a range of temperatures and the activation energy of viscous flow was found to be 20.75kJ/mol. The rheological properties of solutions of B. monandra galactomannan indicate that it has comparable characteristics to other commercially important galactomannans such as guar gum and locust bean gum and hence has potential as a thickener in the formulation of food and other related products. Copyright © 2017 Elsevier B.V. All rights reserved.

Neutron scattering study of dilute supercritical solutions

International Nuclear Information System (INIS)

Cochran, H.D.; Wignall, G.D.; Shah, V.M.; Londono, J.D.; Bienkowski, P.R.

1994-01-01

Dilute solutions in supercritical solvents exhibit interesting microstructures that are related to their dramatic macroscopic behavior. In typical attractive solutions, solutes are believed to be surrounded by clusters of solvent molecules, and solute molecules are believed to congregate in the vicinity of one another. Repulsive solutions, on the other hand, exhibit a local region of reduced solvent density around the solute with solute-solute congregation. Such microstructures influence solubility, partial molar volume, reaction kinetics, and many other properties. We have undertaken to observe these interesting microstructures directly by neutron scattering experiments on dilute noble gas systems including Ar. The three partial structure factors for such systems and the corresponding pair correlation functions can be determined by using the isotope substitution technique. The systems studied are uniquely suited for our objectives because of the large coherent neutron scattering length of the isotope 36 Ar and because of the accurate potential energy functions that are available for use in molecular simulations and theoretical calculations to be compared with the scattering results. We will describe our experiment, the unique apparatus we have built for it, and the neutron scattering results from our initial allocations of beam time. We will also describe planned scattering experiments to follow those with noble gases, including study of long-chain molecules in supercritical solvents. Such studies will involve hydrocarbon mixtures with and without deuteration to provide contrast

Ion-exchange properties of cesium and strontium into zeolites from sodium salt solutions

International Nuclear Information System (INIS)

Kanno, Takuji; Hashimoto, Hiroyuki; Ohtani, Tozo.

1978-01-01

The ion-exchange properties of cesium and strontium into zeolite from sodium salt solution has been studied in zeolite A, zeolite X, zeolite Y, mordenite and clinoptilolite. The distribution of cesium into mordenite from about 1 -- 2 M sodium chloride and sodium hydroxide solutions is considerably larger than that into zeolite A. The distribution coefficient for 2 M solution of sodium salts was about 300. Therefore, the separation of cesium from sodium salt solution is possible by using mordenite. The distribution of strontium into zeolites form 1 -- 2 M solutions of sodium chloride and sodium nitrate were in the order of zeolite A>zeolite X>zeolite Y asymptoticaly equals mordenite. The distribution coefficient of 230 was obtained for 1 M solutions of sodium salts. The anion in solutions had no effect on the distribution of cesium and strontium into zeolite from sodium salt solution. (author)

Colloidal silver solutions with antimicrobial properties

International Nuclear Information System (INIS)

Petica, A.; Gavriliu, S.; Lungu, M.; Buruntea, N.; Panzaru, C.

2008-01-01

Some colloidal silver solutions involving the electrochemical technique with 'sacrificial anode method and different stabilizers and co-stabilizers' have been prepared. A constant current pulse generator with stirrer at different working times has been used. To achieve stable colloidal silver solutions, a mix of different tensioactive agents namely [poly (N-vinylpyrrolidone)], Na-naphthalene sulphonate, Na-lauryl sulfate and Na-dodecyl sulphonate were tested. The effects of these various mixes of polymer and ionic surfactants upon the Ag concentration and UV-vis spectra of silver nanoparticles were determined by spectrophotometer techniques. The nanoparticles sizes have been analyzed through dynamic light scattering technique and the silver nanoparticle morphology has been evidenced by transmission electron microscopy (TEM). Micobiological analysis has been made by determining minimal inhibitorial concentration upon the following germs: Staphylococcus aureus (ATCC) (Gram-positive cocci), Pseudomonas aeruginosa (ATTC), Escherichia coli (ATCC) and Acinetobacter spp. (Gram-negative coccobacillus). To evaluate the antifungal effect, the antibiogram method involving various tests using a fungi mix of Aspergillus, Penicillium and Trichoderma species has been used. The presented method allows obtaining of some stable colloidal solutions containing up to 35 ppm of Ag with very good antimicrobial and antifungal properties

Colloidal silver solutions with antimicrobial properties

Energy Technology Data Exchange (ETDEWEB)

Petica, A. [INCDIE ICPE-Advanced Research, Bucharest (Romania)], E-mail: petica@icpe-ca.ro; Gavriliu, S.; Lungu, M.; Buruntea, N. [INCDIE ICPE-Advanced Research, Bucharest (Romania); Panzaru, C. [Institute of Medicine and Pharmacy, Iassy (Romania)

2008-08-25

Some colloidal silver solutions involving the electrochemical technique with 'sacrificial anode method and different stabilizers and co-stabilizers' have been prepared. A constant current pulse generator with stirrer at different working times has been used. To achieve stable colloidal silver solutions, a mix of different tensioactive agents namely [poly (N-vinylpyrrolidone)], Na-naphthalene sulphonate, Na-lauryl sulfate and Na-dodecyl sulphonate were tested. The effects of these various mixes of polymer and ionic surfactants upon the Ag concentration and UV-vis spectra of silver nanoparticles were determined by spectrophotometer techniques. The nanoparticles sizes have been analyzed through dynamic light scattering technique and the silver nanoparticle morphology has been evidenced by transmission electron microscopy (TEM). Micobiological analysis has been made by determining minimal inhibitorial concentration upon the following germs: Staphylococcus aureus (ATCC) (Gram-positive cocci), Pseudomonas aeruginosa (ATTC), Escherichia coli (ATCC) and Acinetobacter spp. (Gram-negative coccobacillus). To evaluate the antifungal effect, the antibiogram method involving various tests using a fungi mix of Aspergillus, Penicillium and Trichoderma species has been used. The presented method allows obtaining of some stable colloidal solutions containing up to 35 ppm of Ag with very good antimicrobial and antifungal properties.

Properties of concentrated plutonium nitrate solutions

International Nuclear Information System (INIS)

Gray, J.H.; Swanson, J.L.

1978-01-01

Selected properties were measured for solutions containing about 500 and 700 g/l plutonium (IV) in 4--5M nitric acid: density, viscosity, vapor pressure, boiling point, radiolytic gas (H 2 ) evolution rates, and corrosion rate on Ti and 304L stainless steel. Pu solubility was determined to be 550 to 800 g/l in 2.5 to 7M HNO 3 at ambient temperature and 820 to 860 g/l in 3M HNO 3 at 50 0 C

Effect of Na2CO3 degumming concentration on LiBr-formic acid-silk fibroin solution properties

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Liu Zhi

2016-01-01

Full Text Available Salt-acid system has been proved to be of high efficiency for silk fibroin dissolution. Using salt-acid system to dissolve silk, native silk fibrils can be preserved in the regenerated solution. Increasing experiments indicate that acquirement of silk fibrils in solution is strongly associated with the degumming process. In this study, the effect of sodium carbonate degumming concentration on solution properties based on lithium bromide-formic acid dissolution system was systematically investigated. Results showed that the morphology transformation of silk fibroin in solution from nanospheres to nanofibrils is determined by sodium carbonate concentration during the degumming process. Solutions containing different silk fibroin structure exhibited different rheological behaviors and different electrospinnability, leading to different electrospun nanofibre properties. The results have guiding significance for preparation and application of silk fibroin solutions.

Methylamine-hydrogen exchange Part III. Physicochemical properties of amide-amine solutions

International Nuclear Information System (INIS)

Srinivasa, K.; Dave, S.M.

1983-01-01

Different physicochemical properties of potassium methylamide/methylamine solutions have been compiled and reviewed. These properties will be quite useful in design calculations for plants based on amine-hydrogen exchange for the production of heavy water. (author)

Preformulation study of methazolamide for topical ophthalmic delivery: physicochemical properties and degradation kinetics in aqueous solutions.

Science.gov (United States)

Jiang, Sunmin; Wang, Fengzhen; Zhu, Shuning; Zhang, Xiumei; Guo, Zhigang; Li, Rui; Xu, Qunwei

2013-05-20

Methazolamide (MTZ) is an anti-glaucoma drug. The present paper aims to characterize the physicochemical properties and degradation kinetics of MTZ to provide a basis for topical ophthalmic delivery. With the increase in pH (pH 5.5-8.0) of aqueous solution, the solubility of the compound increased while the partition coefficient (Ko/w) which was estimated in the system n-octanol/aqueous solution decreased. The degradation of MTZ in aqueous solution followed pseudo-first-order kinetic. The degradation rate kpH is the rate in the absence of buffer catalysis. Plotting the natural logarithm of kpH versus the corresponding pH value gave a V-shaped pH-rate profile with a maximum stability at pH 5.0. The degradation rate constants as a function of the temperature obeyed the Arrhenius equation (R(2)=0.9995 at pH 7.0 and R(2)=0.9955 at pH 9.0, respectively). A decrease in ionic strength and buffer concentration displayed a stabilizing effect on MTZ. Buffer species also influenced the MTZ hydrolysis. Phosphate buffer system was more catalytic than tris and borate buffer systems. In brief, it is important to consider the physicochemical properties and the stability of MTZ during formulation. Copyright © 2013 Elsevier B.V. All rights reserved.

Microstructure, mechanical property and metal release of As-SLM CoCrW alloy under different solution treatment conditions.

Science.gov (United States)

Lu, Yanjin; Wu, Songquan; Gan, Yiliang; Zhang, Shuyuan; Guo, Sai; Lin, Junjie; Lin, Jinxin

2015-03-01

In the study, the microstructure, mechanical property and metal release behavior of selective laser melted CoCrW alloys under different solution treatment conditions were systemically investigated to assess their potential use in orthopedic implants. The effects of the solution treatment on the microstructure, mechanical properties and metal release were systematically studied by OM, SEM, XRD, tensile test, and ICP-AES, respectively. The XRD indicated that during the solution treatment the alloy underwent the transformation of γ-fcc to ε-hcp phase; the ε-hcp phase nearly dominated in the alloy when treated at 1200°C following the water quenching; the results from OM, SEM showed that the microstructural change was occurred under different solution treatments; solution at 1150°C with furnace cooling contributed to the formation of larger precipitates at the grain boundary regions, while the size and number of the precipitates was decreased as heated above 1100°C with the water quenching; moreover, the diamond-like structure was invisible at higher solution temperature over 1150°C following water quenching; compared with the furnace cooling, the alloy quenched by water showed excellent mechanical properties and low amount of metal release; as the alloy heated at 1200°C, the mechanical properties of the alloy reached their optimum combination at UTS=1113.6MPa, 0.2%YS=639.5MPa, and E%=20.1%, whilst showed the lower total quantity of metal release. It is suggested that a proper solution treatment is an efficient strategy for improving the mechanical properties and corrosion resistance of As-SLM CoCrW alloy that show acceptable tensile ductility. Copyright © 2015 Elsevier Ltd. All rights reserved.

Side Effect of Good's Buffers on Optical Properties of Gold Nanoparticle Solutions

DEFF Research Database (Denmark)

Engelbrekt, Christian; Wagner, Michal; Undall-Behrend Christiansen, Mikkel

2016-01-01

spectroscopy. Distinct absorption features at ca. 290 and 360 nm and fluorescence emission in the 408-484 nm range are observed in filtered AuNP-free solutions. Electrochemical oxidation of these buffers generates similar optical properties, suggesting that the degradation products of the buffers contribute...... to the optical properties of AuNP solutions. This work indicates deeper evaluation of fluorescence signals based on metal NPs or NCs is needed....

The Influence of the Osmotic Dehydration Process on Physicochemical Properties of Osmotic Solution.

Science.gov (United States)

Lech, Krzysztof; Michalska, Anna; Wojdyło, Aneta; Nowicka, Paulina; Figiel, Adam

2017-12-16

The osmotic dehydration (OD) process consists of the removal of water from a material during which the solids from the osmotic solution are transported to the material by osmosis. This process is commonly performed in sucrose and salt solutions. Taking into account that a relatively high consumption of those substances might have a negative effect on human health, attempts have been made to search for alternatives that can be used for osmotic dehydration. One of these is an application of chokeberry juice with proven beneficial properties to human health. This study aimed to evaluate the physicochemical properties of the OD solution (chokeberry juice concentrate) before and after the osmotic dehydration of carrot and zucchini. The total polyphenolics content, antioxidant capacity (ABTS, FRAP), dynamic viscosity, density, and water activity were examined in relation to the juice concentration used for the osmotic solution before and after the OD process. During the osmotic dehydration process, the concentration of the chokeberry juice decreased. Compounds with lower molecular weight and lower antioxidant capacity present in concentrated chokeberry juice had a stronger influence on the exchange of compounds during the OD process in carrot and zucchini. The water activity of the osmotic solution increased after the osmotic dehydration process. It was concluded that the osmotic solution after the OD process might be successfully re-used as a product with high quality for i.e. juice production.

Preliminary study on lithium-salt aqueous solution blanket

International Nuclear Information System (INIS)

Yoshida, Hiroshi; Naruse, Yuji; Yamaoka, Mitsuaki; Ohara, Atsushi; Ono, Kiyoshi; Kobayashi, Shigetada.

1992-06-01

Aqueous solution blanket using lithium salts such as LiNO 3 and LiOH have been studied in the US-TIBER program and ITER conceptual design activity. In the JAERI/LANL collaboration program for the joint operation of TSTA (Tritium Systems Test Assembly), preliminary design work of blanket tritium system for lithium ceramic blanket, aqueous solution blanket and liquid metal blanket, have been performed to investigate technical feasibility of tritium demonstration tests using the TSTA. Detail study of the aqueous solution blanket concept have not been performed in the Japanese fusion program, so that this study was carried out to investigate features of its concept and to evaluated its technical problems. The following are the major items studied in the present work: (i) Neutronics of tritium breeding ratio and shielding performance Lithium concentration, Li-60 enrichment, beryllium or lead, composition of structural material/beryllium/solution, heavy water, different lithium-salts (ii) Physicochemical properties of salts Solubility, corrosion characteristics and compatibility with structural materials, radiolysis (iii) Estimation of radiolysis in ITER aqueous solution blanket. (author)

Rheological properties of concentrated solutions of carboxymethyl starch

Directory of Open Access Journals (Sweden)

Stojanović Željko

2003-01-01

Full Text Available Carboxymethyl starch was synthesized by the esterification of starch with monochloroacetic acid in ethanol as a reaction medium. Three samples of carboxymethyl starch having different degrees of substitution were prepared. The influence of temperature on the viscosity of concentrated carboxymethyl starch solutions, as well as the dynamic-mechanical properties of the concentrated solutions were investigated. The activation energy of viscous flow was determined and it was found that it decreased with increasing degree of substitution. The results of the dynamic-mechanical measurements showed that solutions of starch and carboxymethyl starches with higher degrees of substitution behave as gels. Values of the storage modulus in the rubbery plateau were used to calculate the molar masses between two points of physical crosslinking, the density of crosslinking and the distance between two points of crosslinking.

Coupling between magnetic and optical properties of stable Au-Fe solid solution nanoparticles

Energy Technology Data Exchange (ETDEWEB)

De Julian Fernandez, C; Novak, R L; Bogani, L; Caneschi, A [INSTM RU at the Department of Chemistry of the University of Firenze, via della Lastruccia 3, 50019 Sesto Fiorentino (Italy); Mattei, G; Mazzoldi, P [Department of Physics, CNISM and University of Padova, via Marzolo 8, 35131 Padova (Italy); Paz, E; Palomares, F J [Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco, 28049 Madrid (Spain); Cavigli, L, E-mail: cesar.dejulian@unifi.it [Department of Physics-LENS, University of Florence, via Sansone 1, 50019 Sesto Fiorentino (Italy)

2010-04-23

Au-Fe nanoparticles constitute one of the simplest prototypes of a multifunctional nanomaterial that can exhibit both magnetic and optical (plasmonic) properties. This solid solution, not feasible in the bulk phase diagram in thermal equilibrium, can be formed as a nanostructure by out-of-equilibrium processes. Here, the novel magnetic, optical and magneto-optical properties of ion-implanted Au-Fe solid solution nanoparticles dispersed in a SiO{sub 2} matrix are investigated and correlated. The surface plasmon resonance of the Au-Fe nanoparticles with almost equicomposition is strongly damped when compared to pure Au and to Au-rich Au-Fe nanoparticles. In all cases, the Au atoms are magnetically polarized, as measured by x-ray magnetic circular dichroism, and ferromagnetically coupled with Fe atoms. Although the chemical stability of Au-Fe nanoparticles is larger than that of Fe nanoparticles, both the magnetic moment per Fe atom and the order temperature are smaller. These results suggest that electronic and magnetic properties are more influenced by the hybridization of the electronic bands in the Au-Fe solid solution than by size effects. On the other hand, the magneto-optical transitions allowed in the vis-nIR spectral regions are very similar. In addition, we also observe, after studying the properties of thermally treated samples, that the Au-Fe alloy is stabilized, not by surface effects, but by the combination of the out-of-equilibrium nature of the ion implantation technique and by changes in the properties due to size effects.

Coupling between magnetic and optical properties of stable Au-Fe solid solution nanoparticles

International Nuclear Information System (INIS)

De Julian Fernandez, C; Novak, R L; Bogani, L; Caneschi, A; Mattei, G; Mazzoldi, P; Paz, E; Palomares, F J; Cavigli, L

2010-01-01

Au-Fe nanoparticles constitute one of the simplest prototypes of a multifunctional nanomaterial that can exhibit both magnetic and optical (plasmonic) properties. This solid solution, not feasible in the bulk phase diagram in thermal equilibrium, can be formed as a nanostructure by out-of-equilibrium processes. Here, the novel magnetic, optical and magneto-optical properties of ion-implanted Au-Fe solid solution nanoparticles dispersed in a SiO 2 matrix are investigated and correlated. The surface plasmon resonance of the Au-Fe nanoparticles with almost equicomposition is strongly damped when compared to pure Au and to Au-rich Au-Fe nanoparticles. In all cases, the Au atoms are magnetically polarized, as measured by x-ray magnetic circular dichroism, and ferromagnetically coupled with Fe atoms. Although the chemical stability of Au-Fe nanoparticles is larger than that of Fe nanoparticles, both the magnetic moment per Fe atom and the order temperature are smaller. These results suggest that electronic and magnetic properties are more influenced by the hybridization of the electronic bands in the Au-Fe solid solution than by size effects. On the other hand, the magneto-optical transitions allowed in the vis-nIR spectral regions are very similar. In addition, we also observe, after studying the properties of thermally treated samples, that the Au-Fe alloy is stabilized, not by surface effects, but by the combination of the out-of-equilibrium nature of the ion implantation technique and by changes in the properties due to size effects.

Coupling between magnetic and optical properties of stable Au-Fe solid solution nanoparticles

Science.gov (United States)

de Julián Fernández, C.; Mattei, G.; Paz, E.; Novak, R. L.; Cavigli, L.; Bogani, L.; Palomares, F. J.; Mazzoldi, P.; Caneschi, A.

2010-04-01

Au-Fe nanoparticles constitute one of the simplest prototypes of a multifunctional nanomaterial that can exhibit both magnetic and optical (plasmonic) properties. This solid solution, not feasible in the bulk phase diagram in thermal equilibrium, can be formed as a nanostructure by out-of-equilibrium processes. Here, the novel magnetic, optical and magneto-optical properties of ion-implanted Au-Fe solid solution nanoparticles dispersed in a SiO2 matrix are investigated and correlated. The surface plasmon resonance of the Au-Fe nanoparticles with almost equicomposition is strongly damped when compared to pure Au and to Au-rich Au-Fe nanoparticles. In all cases, the Au atoms are magnetically polarized, as measured by x-ray magnetic circular dichroism, and ferromagnetically coupled with Fe atoms. Although the chemical stability of Au-Fe nanoparticles is larger than that of Fe nanoparticles, both the magnetic moment per Fe atom and the order temperature are smaller. These results suggest that electronic and magnetic properties are more influenced by the hybridization of the electronic bands in the Au-Fe solid solution than by size effects. On the other hand, the magneto-optical transitions allowed in the vis-nIR spectral regions are very similar. In addition, we also observe, after studying the properties of thermally treated samples, that the Au-Fe alloy is stabilized, not by surface effects, but by the combination of the out-of-equilibrium nature of the ion implantation technique and by changes in the properties due to size effects.

Physical Property Modeling of Concentrated Cesium Eluate Solutions, Part I - Derivation of Models

Energy Technology Data Exchange (ETDEWEB)

Choi, A.S.; Pierce, R. A.; Edwards, T. B.; Calloway, T. B.

2005-09-15

Major analytes projected to be present in the Hanford Waste Treatment Plant cesium ion-exchange eluate solutions were identified from the available analytical data collected during radioactive bench-scale runs, and a test matrix of cesium eluate solutions was designed within the bounding concentrations of those analytes. A computer model simulating the semi-batch evaporation of cesium eluate solutions was run in conjunction with a multi-electrolyte aqueous system database to calculate the physical properties of each test matrix solution concentrated to the target endpoints of 80% and 100% saturation. The calculated physical properties were analyzed statistically and fitted into mathematical expressions for the bulk solubility, density, viscosity, heat capacity and volume reduction factor as a function of temperature and concentration of each major analyte in the eluate feed. The R{sup 2} of the resulting physical property models ranged from 0.89 to 0.99.

Photoelectrochemical properties of CdSesub(x)Tesub(1-x) semiconducting solid solutions

International Nuclear Information System (INIS)

Kolbasov, G.Ya.; Karpov, I.I.; Pavelets, A.M.; Khanat, L.N.

1985-01-01

Photoelectrochemical properties of polycrystalline films of solid solutions CdSesub(x)Tesub(1-x) at x=0.5-0.8 are studied. Films from 5 to 30 μm thickness had hexagonal or mixed cubic and hexogonal structures depending on the compositions. All compositions had the electron type of conductivity. Alkali solutions of Na 2 S and S were used as electrolyte. Polarization characteristics of the CdSesub(0.5)Tesub(0.5) photoelectrode, curves of spectral dependence of photo electrochemical current and of the changes of photo-e.m.f. on electrode potential are plotted

Examination of rheological properties of aqueous solutions of sodium caseinate

OpenAIRE

Jolanta Gawałek; Piotr Wesołowski

2012-01-01

Application of sodium caseinate as a functional additive in manufacturing processes requires production of its concentrated aqueous solutions which, in industrial conditions, presents a number of difficulties. In order to develop an effective and optimal industrial process of mixing – manufacturing a concentrated solution of sodium caseinate, it is essential to know rheological properties in a definite range of concentrations changing in the course of the dissolving process. The materia...

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...

Nanometric solid solutions of the fluorite and perovskite type crystal structures: Synthesis and properties

Directory of Open Access Journals (Sweden)

Snežana Bošković

2012-09-01

Full Text Available In this paper a short review of our results on the synthesis of nanosized CeO2, CaMnO3 and BaCeO3 solid solutions are presented. The nanopowders were prepared by two innovative methods: self propagating room temperature synthesis (SPRT and modified glycine/nitrate procedure (MGNP. Different types of solid solutions with rare earth dopants in concentrations ranging from 0–0.25 mol% were synthesized. The reactions forming solid solutions were studied. In addition, the characteristics of prepared nanopowders, phenomena during sintering and the properties of sintered samples are discussed.

Solution Properties of Murine Leukemia Virus Gag Protein: Differences from HIV-1 Gag▿

Science.gov (United States)

Datta, Siddhartha A. K.; Zuo, Xiaobing; Clark, Patrick K.; Campbell, Stephen J.; Wang, Yun-Xing; Rein, Alan

2011-01-01

Immature retrovirus particles are assembled from the multidomain Gag protein. In these particles, the Gag proteins are arranged radially as elongated rods. We have previously characterized the properties of HIV-1 Gag in solution. In the absence of nucleic acid, HIV-1 Gag displays moderately weak interprotein interactions, existing in monomer-dimer equilibrium. Neutron scattering and hydrodynamic studies suggest that the protein is compact, and biochemical studies indicate that the two ends can approach close in three-dimensional space, implying the need for a significant conformational change during assembly. We now describe the properties of the Gag protein of Moloney murine leukemia virus (MLV), a gammaretrovirus. We found that this protein is very different from HIV-1 Gag: it has much weaker protein-protein interaction and is predominantly monomeric in solution. This has allowed us to study the protein by small-angle X-ray scattering and to build a low-resolution molecular envelope for the protein. We found that MLV Gag is extended in solution, with an axial ratio of ∼7, comparable to its dimensions in immature particles. Mutational analysis suggests that runs of prolines in its matrix and p12 domains and the highly charged stretch at the C terminus of its capsid domain all contribute to this extended conformation. These differences between MLV Gag and HIV-1 Gag and their implications for retroviral assembly are discussed. PMID:21917964

Study of the properties of dialkyl thiophosphoric acids. Application to the extraction of U, in phosphoric and nitric solutions

International Nuclear Information System (INIS)

Benjelloun, N.

1983-09-01

A study is made of complex formation and liquid-liquid extraction of uranium (VI) by dialkyl-thiophosphoric acids of formula (RO) 2 POSH and by the synergic mixtures: dialkylthiophosphoric acids-phosphine oxides. The aqueous phases studied consist of concentrated phosphoric acid solutions and nitric acid solutions. Several methods, including distribution coefficient measurements, U.V., visible and infrared absorption spectrophotometries and magnetic resonance, were used to study the extraction mechanisms and the structures of species formed in the organic phase. The influence of different parameters (partition of extraction agent, dimerisation, acid ligand-phosphine oxide association, extraction of inorganic acids...) on the uranium (VI) distribution coefficients enabled the constants of complex formation in the aqueous phase and extraction in the organic phase to be determined. These various properties were compared with those of dialkyl phosphoric and dithiophosphoric acids. The mechanisms established prove that sulfur donors ligands form stable complexes with UO 2 2+ ions although U(VI) is considered as a ''hard class a'' acceptor according to Ahrland's classification [fr

Properties of scintillator solutes

International Nuclear Information System (INIS)

Fluornoy, J.M.

1998-06-01

This special report summarizes measurements of the spectroscopic and other properties of the solutes that were used in the preparation of several new liquid scintillators developed at EG and G/Energy Measurements/Santa Barbara Operations (the precursor to Bechtel Nevada/Special Technologies Laboratory) on the radiation-to-light converter program. The data on the individual compounds are presented in a form similar to that used by Prof. Isadore Berlman in his classic handbook of fluorescence spectra. The temporal properties and relative efficiencies of the new scintillators are presented in Table 1, and the efficiencies as a function of wavelength are presented graphically in Figure 1. In addition, there is a descriptive glossary of the abbreviations used herein. Figure 2 illustrates the basic structures of some of the compounds and of the four solvents reported in this summary. The emission spectra generally exhibit more structure than the absorption spectra, with the result that the peak emission wavelength for a given compound may lie several nm away from the wavelength, λ avg , at the geometric center of the emission spectrum. Therefore, the author has chosen to list absorption peaks, λ max , and emission λ avg values in Figures 3--30, as being most illustrative of the differences between the compounds. The compounds, BHTP, BTPB, ADBT, and DPTPB were all developed on this program. P-terphenyl, PBD, and TPB are commercially available blue emitters. C-480 and the other longer-wavelength emitters are laser dyes available commercially from Exciton Corporation. 1 ref., 30 figs

Ideal solution behaviour of glassy Cu–Ti, Zr, Hf alloys and properties of amorphous copper

International Nuclear Information System (INIS)

Ristić, R.; Cooper, J.R.; Zadro, K.; Pajić, D.; Ivkov, J.; Babić, E.

2015-01-01

Highlights: • Ideal solution behaviour (ISB) is established in all Cu–Ti, Zr, Hf glassy alloys. • ISB enables reliable estimates for various properties of amorphous Cu. • ISB also impacts glass forming ability in these and probably other similar alloys. - Abstract: A comprehensive study of selected properties of amorphous (a) Cu–TE alloys (TE = Ti, Zr and Hf) has been performed. Data for average atomic volumes of a-Cu–Hf, Ti alloys combined with literature data show that ideal solution behaviour (Vegard’s law) extends over the whole glass forming range (GFR) in all a-Cu–TE alloys. This enables one to obtain an insight into some properties and probable atomic arrangements for both, a-TEs (Ristić et al., 2010) and a-Cu by extrapolation of the data for alloys. Indeed the atomic volumes and other properties studied for all a-Cu–TE alloys extrapolate to the same values for a-Cu. Depending on the property, these values are either close to those of crystalline (c) Cu, or are close to those for liquid (L) Cu. In particular, the electronic transport properties of a-Cu seem close to those of L-Cu, whereas the static properties, such as the density of states, and Young’s modulus, converge to those of c-Cu. The possible impact of these results on our understanding of a-Cu–TE alloys, including glass forming ability, is discussed

EFFECTS OF INORGANIC SALT SOLUTION ON SOME PROPERTIES OF COMPACTED CLAY LINERS

Directory of Open Access Journals (Sweden)

KHALID R. MAHMOOD AL-JANABI

2017-12-01

Full Text Available Processed and natural clays are widely used to create impermeable liners in solid waste disposal landfills. The engineering properties of clay liners can be significantly affected by the leachate from the waste mass. In this study, the effect of inorganic salt solutions will be investigated. These solutions used at different concentrations. Two type of inorganic salt MnSO4 and FeCl3 are used at different concentration 2%,5%, 10%. Clay used in this study was the CL- clay (kaolinite. The results show that the consistency limits and unconfined compressive strength increased as the concentration of salts increased. While the permeability tends to decrease as salt concentration increased. Also, the compression index decreases as the concentration increased from 2% to 5%. The swelling index tends to increase slightly as the concentration of MnSO4 increased, while its decrease as the concentration of FeCl3. In this paper, it is aimed to investigate the performance of compacted clay liner exposed to the certain chemicals generated by the leachate and their effects on the geotechnical properties of compacted clay liner such consistency limits, permeability coefficient, compressibility characteristics and unconfined compressive strength.

Improvement of Physico-mechanical Properties of Partially Amorphous Acetaminophen Developed from Hydroalcoholic Solution Using Spray Drying Technique

Science.gov (United States)

Sadeghi, Fatemeh; Torab, Mansour; Khattab, Mostafa; Homayouni, Alireza; Afrasiabi Garekani, Hadi

2013-01-01

Objective(s): This study was performed aiming to investigate the effect of particle engineering via spray drying of hydroalcoholic solution on solid states and physico-mechanical properties of acetaminophen. Materials and Methods: Spray drying of hydroalcoholic solution (25% v/v ethanol/water) of acetaminophen (5% w/v) in the presence of small amounts of polyninylpyrrolidone K30 (PVP) (0, 1.25, 2.5 and 5% w/w based on acetaminophen weight) was carried out. The properties of spray dried particles namely morphology, surface characteristics, particle size, crystallinity, dissolution rate and compactibility were evaluated. Results: Spray drying process significantly changed the morphology of acetaminophen crystals from acicular (rod shape) to spherical microparticle. Differential scanning calorimetery (DSC) and x-ray powder diffraction (XRPD) studies ruled out any polymorphism in spray dried samples, however, a major reduction in crystallinity up to 65%, especially for those containing 5% w/w PVP was observed. Spray dried acetaminophen particles especially those obtained in the presence of PVP exhibited an obvious improvement of the dissolution and compaction properties. Tablets produced from spray dried samples exhibited excellent crushing strengths and no tendency to cap. Conclusions: The findings of this study revealed that spray drying of acetaminophen from hydroalcoholic solution in the presence of small amount of PVP produced partially amorphous particles with improved dissolution and excellent compaction properties. PMID:24379968

Solution, thermal and optical properties of bis(pyridinium salt)s as ionic liquids

International Nuclear Information System (INIS)

Jo, Tae Soo; Koh, Jung Jae; Han, Haesook; Bhowmik, Pradip K.

2013-01-01

Bis(pyridinium salt)s containing different alkyl chain lengths and various organic counterions were prepared by the ring-transmutation reaction of bis(pyrylium tosylate) with aliphatic amines in dimethyl sulfoxide at 130–135 °C for 18 h and their tosylate counterions were exchanged to other anions such as triflimide, methyl orange, and dioctyl sulfosuccinate by the metathesis reaction in a common organic solvent. Their chemical structures were established by using 1 H, 19 F, and 13 C NMR spectra. The thermal properties of bis(pyridinium salt)s were studied by DSC and TGA measurements. Some of the dicationic salts provided low melting points below 100 °C and some of them displayed amorphous properties. Polarized optical microscopy studies revealed the crystal structures prior to melting temperatures in some cases. Their optical properties were examined by using UV–Vis and photoluminescent spectrometers; and they emitted blue light both in the solution and solid states regardless of their microstructures, counterions, and the polarity of organic solvents. However, most of these salts exhibited hypsochromic shifts in their emission peaks in the solid state when compared with those of their solution spectra. Due to unique properties of methyl orange anion as a pH indicator, two of the salts showed different color change in varying concentrations of triflic acid in common organic solvents, demonstrating their potential use as an acid sensor in methanol, acetonitrile and acetone. Highlights: ► Luminescent dicationic salts were synthesized by ring-transmutation and metathesis reactions. ► Thermal and optical properties of dicationic salts are affected by the size of anion structures. ► Due to the methyl orange counterions, some dicationic salts showed pH- sensing property

Tuning the optical properties of carbon nanotube solutions using amphiphilic self-assembly

Science.gov (United States)

Arnold, Michael S.; Stupp, Samuel I.; Hersam, Mark C.

2003-07-01

Recently it has been shown that aqueous solutions of sodium dodecyl sulfate (SDS) encapsulated and polymer wrapped single-walled carbon nanotubes (SWNTs) fluoresce in the near infrared (NIR) in the regime of the E11 van Hove transitions for semiconducting SWNTs. For bundled SWNTs, fluorescence is observed to be quenched along with a shift and broadening of the absorbance spectrum. Here, we study two other commercially available surfactants, BRIJ-97 and Triton-X-100, by analysis of carbon nanotube fluorescence and absorptivity in the NIR. It is found that changing the surfactant alters the corresponding optical properties of the solubilized carbon nanotubes. The NIR absorbance spectra of BRIJ-97 and Triton-X-100 carbon nanotube solutions are also compared with the absorbance spectrum of NaCl destabilized SDS-SWNT solutions. By controlling the amount of NaCl added to an aqueous solution of SDS-SWNTs, the optical absorbance spectrum can be made to match that of BRIJ-97 and Triton-X-100 solutions. Lastly, a correlation is drawn between the amount of shift in the absorbance spectrum and the fluorescence intensity, independent of surfactant used. This shift and decrease in fluorescence intensity may be due to carbon nanotube bundling.

Factorization properties and spurious solutions in N-body scattering theories

International Nuclear Information System (INIS)

Vanzani, V.

1979-01-01

The origin of spurious solutions in N-body scattering equations is discussed. It is shown that spurious solutions are expected because of specific factorization properties of the homogeneous equations. The equations proposed by Rosenberg, by Mitra, Gillespie, Sugar and Panchapakesan, by Takahashi and Mishima, by Alessandrini, by Sasakawa, by Sloan, Bencze and Redish, by Weinberg and van Winter and by Avishai are considered. It is explicitly shown that spurious multipliers arise from repeated employment of resolvent equations or, equiValently, from generalized iteration procedure

Structural properties of glucose-dimethylsulfoxide solutions probed by Raman spectroscopy

Science.gov (United States)

Paolantoni, Marco; Gallina, Maria Elena; Sassi, Paola; Morresi, Assunta

2009-04-01

Raman spectroscopy was employed to achieve a molecular level description of solvation properties in glucose-dimethylsulfoxide (DMSO) solutions. The analysis of Raman spectra confirms the importance of the dipole-dipole interaction in determining structural properties of pure DMSO; the overall intermolecular structure is maintained in the whole 20-75 °C temperature range investigated. The blueshift of the CH stretching modes observed at higher temperatures points out that CH3⋯O contacts contribute to the cohesive energy of the DMSO liquid system. The addition of glucose perturbs the intermolecular ordering of DMSO owing to the formation of stable solute-solvent hydrogen bonds. The average number of OH⋯OS contacts (3.2±0.3) and their corresponding energy (˜20 kJ/mol) were estimated. Besides, the concentration dependence of the CH stretching bands and the behavior of the noncoincidence effect on the SO band, suggest that the dipole-dipole and CH3⋯O interactions among DMSO molecules are disfavored within the glucose solvation layer. These findings contribute to improve our understanding about the microscopic origin of solvent properties of DMSO toward more complex biomolecular systems.

Structure and dynamics of solutions

CERN Document Server

Ohtaki, H

2013-01-01

Recent advances in the study of structural and dynamic properties of solutions have provided a molecular picture of solute-solvent interactions. Although the study of thermodynamic as well as electronic properties of solutions have played a role in the development of research on the rate and mechanism of chemical reactions, such macroscopic and microscopic properties are insufficient for a deeper understanding of fast chemical and biological reactions. In order to fill the gap between the two extremes, it is necessary to know how molecules are arranged in solution and how they change their pos

Water movement through plant roots - exact solutions of the water flow equation in roots with linear or exponential piecewise hydraulic properties

Science.gov (United States)

Meunier, Félicien; Couvreur, Valentin; Draye, Xavier; Zarebanadkouki, Mohsen; Vanderborght, Jan; Javaux, Mathieu

2017-12-01

In 1978, Landsberg and Fowkes presented a solution of the water flow equation inside a root with uniform hydraulic properties. These properties are root radial conductivity and axial conductance, which control, respectively, the radial water flow between the root surface and xylem and the axial flow within the xylem. From the solution for the xylem water potential, functions that describe the radial and axial flow along the root axis were derived. These solutions can also be used to derive root macroscopic parameters that are potential input parameters of hydrological and crop models. In this paper, novel analytical solutions of the water flow equation are developed for roots whose hydraulic properties vary along their axis, which is the case for most plants. We derived solutions for single roots with linear or exponential variations of hydraulic properties with distance to root tip. These solutions were subsequently combined to construct single roots with complex hydraulic property profiles. The analytical solutions allow one to verify numerical solutions and to get a generalization of the hydric behaviour with the main influencing parameters of the solutions. The resulting flow distributions in heterogeneous roots differed from those in uniform roots and simulations led to more regular, less abrupt variations of xylem suction or radial flux along root axes. The model could successfully be applied to maize effective root conductance measurements to derive radial and axial hydraulic properties. We also show that very contrasted root water uptake patterns arise when using either uniform or heterogeneous root hydraulic properties in a soil-root model. The optimal root radius that maximizes water uptake under a carbon cost constraint was also studied. The optimal radius was shown to be highly dependent on the root hydraulic properties and close to observed properties in maize roots. We finally used the obtained functions for evaluating the impact of root maturation

General properties of solutions to inhomogeneous Black-Scholes equations with discontinuous maturity payoffs

Science.gov (United States)

O, Hyong-Chol; Jo, Jong-Jun; Kim, Ji-Sok

2016-02-01

We provide representations of solutions to terminal value problems of inhomogeneous Black-Scholes equations and study such general properties as min-max estimates, gradient estimates, monotonicity and convexity of the solutions with respect to the stock price variable, which are important for financial security pricing. In particular, we focus on finding representation of the gradient (with respect to the stock price variable) of solutions to the terminal value problems with discontinuous terminal payoffs or inhomogeneous terms. Such terminal value problems are often encountered in pricing problems of compound-like options such as Bermudan options or defaultable bonds with discrete default barrier, default intensity and endogenous default recovery. Our results can be used in pricing real defaultable bonds under consideration of existence of discrete coupons or taxes on coupons.

Electronic Properties of Functional Biomolecules at Metal/Aqueous Solution Interfaces

DEFF Research Database (Denmark)

Zhang, Jingdong; Chi, Qijin; Kuznetsov, A.M.

2002-01-01

in electronic properties and stochastic single-molecule features and can be probed by new methods which approach the single-molecule level. Olle of these is in situ scanning tunneling microscopy (STM) in which single-molecule electronic properties directly in aqueous solution are probed. In situ STM combined...... with physical electrochemistry, single-crystal electrodes, and spectroscopic methods is now a new dimension in interfacial bioelectrochemistry. We overview first same approaches to spectroscopic single-molecule imaging, including fluorescence spectroscopy, chemical reaction dynamics, atomic force microscopy...

Study of colloidal properties of natural and Al-pillared smectite and removal of copper ions from an aqueous solution.

Science.gov (United States)

Sartor, Lucas Resmini; de Azevedo, Antonio Carlos; Andrade, Gabriel Ramatis Pugliese

2015-01-01

In this study, an Al-pillared smectite was synthesized and changes in its colloidal properties were investigated. The pillaring solution was prepared by mixing 0.4 mol L(-1) NaOH and 0.2 mol L(-1) AlCl3.6H2O solutions. Intercalated clays were heated to obtain the pillared clay, and X-ray diffractometry (XRD), X-ray fluorescence (XRF), Fourier transform infrared (FTIR) spectroscopy and N2 sorption/desorption isotherms analysis were done to characterize the changes in clay properties. Moreover, adsorption experiments were carried out in order to evaluate the capacity of the pillared clays to remove Cu2+ from an aqueous solution and to characterize the interaction between adsorbent and adsorbate. The results indicate that the natural clay has a basal spacing of 1.26 nm, whereas the pillared clays reached 1.78 nm (500°C) and 1.80 nm (350°C) after calcination. XRF analysis revealed an increase in the Al3+ in the pillared clay as compared to the natural clay. The surface area and pore volume (micro and mesoporous) were higher for the pillared clays. Experimental data from the adsorption experiment were fit to Langmuir and Freundlich and Temkin adsorption models, and the former one was the best fit (highest r2 value) for all the clays and lower standard deviation (Δg%) for the natural clay. On the other hand, the Temkin model exhibited Δg% value lower for the pillared clays. Thermodynamics parameters demonstrate that the Cu2+ adsorption process is spontaneous for all the clays, but with higher values for the pillared materials. In addition, application of the Dubinin-Radushkevich model revealed that the bond between the metal and the clay are weak, characterizing a physisorption.

Properties and structures of electrolyte solutions for lithium batteries

Energy Technology Data Exchange (ETDEWEB)

Blomgren, G. E.

1985-01-15

Rules which have been employed to explain and predict solvent properties of lithium battery electrolytes are described and results reviewed. The equilibrium behavior of moderate to high concentration electrolyte solutions is also reviewed. Recent theoretical approaches to explain the behavior are discussed, and a new theory incorporating contact ion pair concepts into an advanced statistical theory for free ions is proposed.

Thermophysical properties of sodium nitrate and sodium chloride solutions and their effects on fluid flow in unsaturated media

International Nuclear Information System (INIS)

Xu, Tianfu; Pruess, Karsten

2001-01-01

Understanding movement of saline sodium nitrate (NaNO 3 ) waste solutions is important for assessing the contaminant migration near leaking waste storage tanks in the unsaturated zone at the Hanford site (Washington, USA). The purpose of this study is to contribute a basic understanding of effects of the thermophysical behavior of NaNO 3 solutions on fluid flow in unsaturated media. We first present mathematical expressions for the dependence of density, viscosity, solubility and vapor pressure of NaNO 3 solutions on both salt concentration and temperature, which were determined by fitting from published measured data. Because the previous studies of thermophysical behavior of sodium chloride (NaCl) solutions can provide a basis for those of NaNO 3 solutions, we also present a comparison of thermophysical properties of both salt solutions. We have implemented the functional thermophysical properties of NaNO 3 solutions into a new TOUGH2 equation-of-state module EWASG-NaNO 3 , which is modified from a previous TOUGH2 equation-of-state module EWASG for NaCl. Using the simulation tool, we have investigated effects of the thermophysical properties on fluid flow in unsaturated media. The effect of density and viscosity of saline solutions has been long recognized. Here we focus our attention on the effect of vapor pressure lowering due to salinity. We present simulations of a one-dimensional problem to study this salinity-driven fluid flow. A number of simulations were performed using different values of thermal conductivity, permeability, and temperature, to illustrate conditions and parameters controlling these processes. Results indicate that heat conduction plays a very important role in this salinity-driven vapor diffusion by maintaining a nearly constant temperature. The smaller the permeability, the more water is transferred into the saline environment. Effects of permeability on water flow are also complicated by effects of capillary pressure and tortuosity. The

Microstructure and mechanical properties of a novel Ti–Al–Cr–Fe titanium alloy after solution treatment

International Nuclear Information System (INIS)

Wang, Zhenguo; Cai, Haijiao; Hui, Songxiao

2015-01-01

Highlights: • Microstructure and mechanical properties of a novel Ti–3.0Al–3.7Cr–2.0Fe alloy were studied. • The effects of cooling rates and solution temperature were considered. • The strength–ductility combination were investigated through different heat treatment. - Abstract: The relationship between microstructure and mechanical properties of a novel Ti–3.0Al–3.7Cr–2.0Fe alloy were studied. The effects of cooling rates and solution temperature were considered. The analysis methods of optical microscope (OM), X-ray diffractometer (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) were used. The results indicate that β and α phase in this alloy are obtained after solution treated at 1183 K on the cooling ways of air cooling and furnace cooling; and β and α″ martensite are observed after quenching in water. Besides, the volume of α phase is decreased with increasing solution temperature. In the present study, the ultimate strength 1065 MPa with 12.0% in elongation of the alloy is acquired under the heat treatment condition of 1183 K/30 min/AC, and the strength–ductility combination in this case is also the best. Under the heat treatment condition of 1183 K/30 min/WQ, the elasticity modulus of the alloy is only 91.3 GPa, as a result of the lower elasticity modulus of β phase

Measurement of properties of a lithium bromide aqueous solution for the determination of the concentration for a prototype absorption machine

International Nuclear Information System (INIS)

Labra, L.; Juárez-Romero, D.; Siqueiros, J.; Coronas, A.; Salavera, D.

2017-01-01

Highlights: • Determination of concentration of absorption mixture for absorption heat transformers. • Measurement of physical properties for heat transformer assessment. • Comparative behavior of Electric conductivity, Refractive index, and density of LiBr-H_2O. - Abstract: An electrolyte solution of Lithium Bromide (LiBr) water was chosen for study because of its wide use in prototype absorption machines. The LiBr must be operated close to the temperature and mass fraction at which lithium bromide achieves the highest efficiency. For the purpose of establishing the concentration in a prototype absorption machines, measurements were made of the properties that vary with temperature and concentration. The selected properties are electrical conductivity, density, refractive indexes and sound velocity. The resulting measured properties values were compared with some values found in previous works. The properties of aqueous lithium bromide solutions were measured at the concentration range of 45–65% of LiBr and temperatures range of 20–80 °C. Semi-empirical correlations that determine the properties of lithium bromide are also proposed. The methods for measuring the properties of aqueous solutions were considered taking into account their reliability, simplicity and sampling time.

Water movement through plant roots – exact solutions of the water flow equation in roots with linear or exponential piecewise hydraulic properties

Directory of Open Access Journals (Sweden)

F. Meunier

2017-12-01

Full Text Available In 1978, Landsberg and Fowkes presented a solution of the water flow equation inside a root with uniform hydraulic properties. These properties are root radial conductivity and axial conductance, which control, respectively, the radial water flow between the root surface and xylem and the axial flow within the xylem. From the solution for the xylem water potential, functions that describe the radial and axial flow along the root axis were derived. These solutions can also be used to derive root macroscopic parameters that are potential input parameters of hydrological and crop models. In this paper, novel analytical solutions of the water flow equation are developed for roots whose hydraulic properties vary along their axis, which is the case for most plants. We derived solutions for single roots with linear or exponential variations of hydraulic properties with distance to root tip. These solutions were subsequently combined to construct single roots with complex hydraulic property profiles. The analytical solutions allow one to verify numerical solutions and to get a generalization of the hydric behaviour with the main influencing parameters of the solutions. The resulting flow distributions in heterogeneous roots differed from those in uniform roots and simulations led to more regular, less abrupt variations of xylem suction or radial flux along root axes. The model could successfully be applied to maize effective root conductance measurements to derive radial and axial hydraulic properties. We also show that very contrasted root water uptake patterns arise when using either uniform or heterogeneous root hydraulic properties in a soil–root model. The optimal root radius that maximizes water uptake under a carbon cost constraint was also studied. The optimal radius was shown to be highly dependent on the root hydraulic properties and close to observed properties in maize roots. We finally used the obtained functions for evaluating the impact

Optimization of foaming properties of sludge protein solution by 60Co γ-ray/H2O2 using response surface methodology

International Nuclear Information System (INIS)

Xiang, Yulin; Xiang, Yuxiu; Wang, Lipeng; Zhang, Zhifang

2016-01-01

Response surface methodology and Box-Behnken experimental design were used to model and optimize the operational parameters of foaming properties of the sludge protein solution by 60 Co γ-ray/H 2 O 2 treatment. The four variables involved in this research were the protein solution concentration, H 2 O 2 , pH and dose. In the range studied, statistical analysis of the results showed that selected variables had a significant effect on protein foaming properties. The optimized conditions contained: protein solution concentration 26.50% (v/v), H 2 O 2 concentration 0.30% (v/v), pH value 9.0, and dose 4.81 kGy. Under optimal conditions, the foamability and foam stability approached 23.3 cm and 21.3 cm, respectively. Regression analysis with R 2 value of 0.9923 (foamability) and 0.9922 (foam stability) indicated a satisfactory correlation between the experimental data and predicted values (response). In addition, based on a feasibility analysis, the 60 Co γ-ray/H 2 O 2 method can improve odor and color of the protein foaming solution. - Highlights: • Effects of 60 Co γ-ray/H 2 O 2 on foaming properties of sludge protein were studied. • Response surface methodology and Box-Behnken experimental design were applied. • 60 Co γ-ray/H 2 O 2 method can improve foaming properties of protein solution.

Influence of hydroxypropylmethyl cellulose-sodium laurylsulfate interaction on rheological properties of the solution

Directory of Open Access Journals (Sweden)

Šaletić Jelena V.

2004-01-01

Full Text Available Interactions between the polymers and surfactants in solution have widely been investigated because of their scientific and technological importance. These interactions can be utilized to modify the physicochemical properties of system in many food products, pharmaceutical formulations, personal care products, paints, pesticides, etc. Interaction between nonionic polymer - hydroxypropylmethyl cellulose (HPMC and anionic surfactant - sodium laurylsulfate (SDS in solution has been investigated in this paper by rheological measurements. Rheological measurements are performed by rotational viscometer at 20°C and changes of rheological characteristics of HPMC solutions (0.5-1.5% with increasing SDS concentrations (0-4.0% were determined. The results of these investigations showed that viscosity of the solution is dependant on HPMC-SDS interaction. At particular SDS concentration viscosity increases, reach maximum and after that decreases until reach constant value. From the viscosity changes the characteristic concentrations of SDS, critical aggregation concentration (cac and polymer saturation point (psp, were determined. These concentrations are in linear relationships with HPMC concentrations. Rheological properties of the solution are strong influenced by HPMC-SDS interaction and exhibits more or less pronounced pseudoplastic behavior, which changes to Newtonian one after the psp has been reached.

Thermodynamic nonequilibrium phase change behavior and thermal properties of biological solutions for cryobiology applications.

Science.gov (United States)

Han, Bumsoo; Bischof, John C

2004-04-01

Understanding the phase change behavior of biomaterials during freezing/thawing including their thermal properties at low temperatures is essential to design and improve cryobiology applications such as cryopreservation and cryosurgery. However, knowledge of phase change behavior and thermal properties of various biomaterials is still incomplete, especially at cryogenic temperatures (solutions--either water-NaCl or phosphate buffered saline (PBS)--with various chemical additives were investigated. The chemical additives studied are glycerol and raffinose as CPAs, an AFP (Type III, molecular weight = 6500), and NaCl as a cryosurgical adjuvant. The phase change behavior was investigated using a differential scanning calorimeter (DSC) and a cryomicroscope. The specific and latent heat of these solutions were also measured with the DSC. The saline solutions have two distinct phase changes--water/ice and eutectic phase changes. During freezing, eutectic solidification of both water-NaCl and PBS are significantly supercooled below their thermodynamic equilibrium eutectic temperatures. However, their melting temperatures are close to thermodynamic equilibrium during thawing. These eutectic phase changes disappear when even a small amount (0.1 M glycerol) of CPA was added, but they are still observed after the addition of an AFP. The specific heats of these solutions are close to that of ice at very low temperatures (< or = -100 degrees C) regardless of the additives, but they increase between -100 degrees C and -30 degrees C with the addition of CPAs. The amount of latent heat, which is evaluated with sample weight, generally decreases with the addition of the additives, but can be normalized to approximately 300 J/g based on the weight of water which participates in the phase change. This illustrates that thermal properties, especially latent heat, of a biomaterial should be evaluated based on the understanding of its phase change behavior. The results of the present

Molecular dynamics simulations of the dielectric properties of fructose aqueous solutions

International Nuclear Information System (INIS)

Sonoda, Milton T; Dolores Elola, M; Skaf, Munir S

2016-01-01

The static dielectric permittivity and dielectric relaxation properties of fructose aqueous solutions of different concentrations ranging from 1.0 to 4.0 mol l −1 are investigated by means of molecular dynamics simulations. The contributions from intra- and interspecies molecular correlations were computed individually for both the static and frequency-dependent dielectric properties, and the results were compared with the available experimental data. Simulation results in the time- and frequency-domains were analyzed and indicate that the presence of fructose has little effect on the position of the fast, high-frequency (>500 cm −1 ) components of the dielectric response spectrum. The low-frequency (<0.1 cm −1 ) components, however, are markedly influenced by sugar concentration. Our analysis indicates that fructose–fructose and fructose–water interactions strongly affect the rotational-diffusion regime of molecular motions in the solutions. Increasing fructose concentration not only enhances sugar–sugar and sugar-water low frequency contributions to the dielectric loss spectrum but also slows down the reorientational dynamics of water molecules. These results are consistent with previous computer simulations carried out for other disaccharide aqueous solutions. (paper)

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.

Methods for partial differential equations qualitative properties of solutions, phase space analysis, semilinear models

CERN Document Server

Ebert, Marcelo R

2018-01-01

This book provides an overview of different topics related to the theory of partial differential equations. Selected exercises are included at the end of each chapter to prepare readers for the “research project for beginners” proposed at the end of the book. It is a valuable resource for advanced graduates and undergraduate students who are interested in specializing in this area. The book is organized in five parts: In Part 1 the authors review the basics and the mathematical prerequisites, presenting two of the most fundamental results in the theory of partial differential equations: the Cauchy-Kovalevskaja theorem and Holmgren's uniqueness theorem in its classical and abstract form. It also introduces the method of characteristics in detail and applies this method to the study of Burger's equation. Part 2 focuses on qualitative properties of solutions to basic partial differential equations, explaining the usual properties of solutions to elliptic, parabolic and hyperbolic equations for the archetypes...

Bayesian estimation of the hydraulic and solute transport properties of a small-scale unsaturated soil column

NARCIS (Netherlands)

Moreira, Paulo H S; Van Genuchten, Martinus Th; Orlande, Helcio R B; Cotta, Renato M.

2016-01-01

In this study the hydraulic and solute transport properties of an unsaturated soil were estimated simultaneously from a relatively simple small-scale laboratory column infiltration/outflow experiment. As governing equations we used the Richards equation for variably saturated flow and a physical

Comparative study of the physicochemical properties of aqueous solutions of the hydrocarbon and fluorocarbon surfactants and their ternary mixtures

Energy Technology Data Exchange (ETDEWEB)

Szymczyk, Katarzyna, E-mail: katarzyna.szymczyk@poczta.umcs.lublin.pl

2014-03-03

Highlights: • Acoustic properties of hydrocarbon and fluorocarbon surfactants were studied. • Auerbach’s relation is not proper for mixtures with fluorocarbon surfactants. • Values of the hydration number decreases at concentrations higher than CMC. • FSO100 and its mixtures are the strongest chaotropes. - Abstract: Speed of sound and density of aqueous solutions of hydrocarbon p-(1,1,3,3-tetramethylbutyl) phenoxypoly(ethyleneglycols) (Triton X-100 (TX100), Triton X-165 (TX165)) and fluorocarbon (Zonyl FSN-100 (FSN100), Zonyl FSO-100 (FSO100)) surfactants as well as their ternary mixtures were measured at 293 K. Taking into account these values and the literature data of the surface tension and viscosity of the studied systems, the values of the isentropic compressibility, apparent specific adiabatic compressibility, hydration number, apparent specific volume and Jones Dole’s A and B-coefficients were determined. For the systems containing FSO100 also the values of dB/dT were determined on the basis of the values of viscosity measured at different temperatures. Next, the calculated thermodynamic properties have been discussed in the term of intermolecular interactions between the components of the mixtures.

Dielectric dispersion, relaxation dynamics and thermodynamic studies of Beta-Alanine in aqueous solutions using picoseconds time domain reflectometry

Science.gov (United States)

Vinoth, K.; Ganesh, T.; Senthilkumar, P.; Sylvester, M. Maria; Karunakaran, D. J. S. Anand; Hudge, Praveen; Kumbharkhane, A. C.

2017-09-01

The aqueous solution of beta-alanine characterised and studied by their dispersive dielectric properties and relaxation process in the frequency domain of 10×106 Hz to 30×109 Hz with varying concentration in mole fractions and temperatures. The molecular interaction and dielectric parameters are discussed in terms of counter-ion concentration theory. The static permittivity (ε0), high frequency dielectric permittivity (ε∞) and excess dielectric parameters are accomplished by frequency depended physical properties and relaxation time (τ). Molecular orientation, ordering and correlation factors are reported as confirmation of intermolecular interactions. Ionic conductivity and thermo dynamical properties are concluded with the behaviour of the mixture constituents. Solute-solvent, solute-solute interaction, structure making and breaking abilities of the solute in aqueous medium are interpreted. Fourier Transform Infrared (FTIR) spectra of beta- alanine single crystal and liquid state have been studied. The 13C Nuclear Magnetic Resonance (NMR) spectral studies give the signature for resonating frequencies and chemical shifts of beta-alanine.

Study of the Changes in Composition of Ammonium Diuranate with Progress of Precipitation, and Study of the Properties of Ammonium Diuranate and its Subsequent Products Produced from both Uranyl Nitrate and Uranyl Fluoride Solutions

Directory of Open Access Journals (Sweden)

Subhankar Manna

2017-04-01

Full Text Available Uranium metal used for fabrication of fuel for research reactors in India is generally produced by magnesio-thermic reduction of UF4. Performance of magnesio-thermic reaction and recovery and quality of uranium largely depends on properties of UF4. As ammonium diuranate (ADU is first product in powder form in the process flow-sheet, properties of UF4 depend on properties of ADU. ADU is generally produced from uranyl nitrate solution (UNS for natural uranium metal production and from uranyl fluoride solution (UFS for low enriched uranium metal production. In present paper, ADU has been produced via both the routes. Variation of uranium recovery and crystal structure and composition of ADU with progress in precipitation reaction has been studied with special attention on first appearance of the precipitate Further, ADU produced by two routes have been calcined to UO3, then reduced to UO2 and hydroflorinated to UF4. Effect of two different process routes of ADU precipitation on the characteristics of ADU, UO3, UO2 and UF4 were studied here.

Study of the changes in composition of ammonium diuranate with progress of precipitation, and study of the properties of ammonium diuranate and its subsequent products produced from both uranyl nitrate and uranyl fluoride solutions

International Nuclear Information System (INIS)

Manna, Subhankar; Kumar, Raj; Satpati, Santosh K.; Roy, Saswati B.; Joshi, Jyeshtharaj B.

2017-01-01

Uranium metal used for fabrication of fuel for research reactors in India is generally produced by magnesio-thermic reduction of UF 4 . Performance of magnesio-thermic reaction and recovery and quality of uranium largely depends on properties of UF 4 . As ammonium diuranate (ADU) is first product in powder form in the process flow-sheet, properties of UF 4 depend on properties of ADU. ADU is generally produced from uranyl nitrate solution (UNS) for natural uranium metal production and from uranyl fluoride solution (UFS) for low enriched uranium metal production. In present paper, ADU has been produced via both the routes. Variation of uranium recovery and crystal structure and composition of ADU with progress in precipitation reaction has been studied with special attention on first appearance of the precipitate Further, ADU produced by two routes have been calcined to UO 3 , then reduced to UO 2 and hydroflorinated to UF 4 . Effect of two different process routes of ADU precipitation on the characteristics of ADU, UO 3 , UO 2 and UF 4 were studied here

Swelling, mechanical and friction properties of PVA/PVP hydrogels after swelling in osmotic pressure solution.

Science.gov (United States)

Shi, Yan; Xiong, Dangsheng; Liu, Yuntong; Wang, Nan; Zhao, Xiaoduo

2016-08-01

The potential of polyvinyl alcohol/polyvinylpyrrolidone (PVA/PVP) hydrogels as articular cartilage replacements was in vitro evaluated by using a macromolecule-based solution to mimic the osmotic environment of cartilage tissue. The effects of osmotic pressure solution on the morphology, crystallinity, swelling, mechanical and friction properties of PVA/PVP hydrogels were investigated by swelling them in non-osmotic and osmotic pressure solutions. The results demonstrated that swelling ratio and equilibrium water content were greatly reduced by swelling in osmotic solution, and the swelling process was found to present pseudo-Fickian diffusion character. The crystallization degree of hydrogels after swelling in osmotic solution increased more significantly when it compared with that in non-osmotic solution. After swelling in osmotic solution for 28days, the compressive tangent modulus and storage modulus of hydrogels were significantly increased, and the low friction coefficient was reduced. However, after swelling in the non-osmotic solution, the compressive tangent modulus and friction coefficient of hydrogels were comparable with those of as-prepared hydrogels. The better material properties of hydrogels in vivo than in vitro evaluation demonstrated their potential application in cartilage replacement. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of sodium tetraborate (borax) on the thermal properties of frozen aqueous sugar and polyol solutions.

Science.gov (United States)

Izutsu, Ken-ichi; Rimando, Annie; Aoyagi, Nobuo; Kojima, Shigeo

2003-06-01

The effect of sodium tetraborate (Na(2)B(4)O(7), borax) on the thermal property of frozen aqueous sugar and polyol solutions was studied through thermal analysis. Addition of borax raised the thermal transition temperature (glass transition temperature of maximally freeze-concentrated solutes; T(g)') of frozen sucrose solutions depending on the borax/sucrose concentration ratios. Changes in the T(g)' of frozen mono- and disaccharide solutions suggested various forms of complexes, including those of a borate ion and two saccharide molecules. Borax exerted the maximum effect to raise the oligosaccharide and dextran T(g)'s at borax/saccharide molar ratios of approximately 1-2 (maltose and maltooligosaccharides), 2 (dextran 1060), 5 (dextran 4900), and 10 (dextran 10200). Further addition of borax lowered T(g)'s of the saccharide solutions. Borax also raised T(g) and T(g)' temperatures of frozen aqueous glycerol solutions. The decreased solute mobility in frozen solutions by the borate-polyol complexes suggested higher collapse temperature in the freeze-drying process and improved stability of biological systems in frozen solutions.

Links between soil properties and steady-state solute transport through cultivated topsoil at the field scale

Science.gov (United States)

Koestel, J. K.; Norgaard, T.; Luong, N. M.; Vendelboe, A. L.; Moldrup, P.; Jarvis, N. J.; Lamandé, M.; Iversen, B. V.; Wollesen de Jonge, L.

2013-02-01

It is known that solute transport through soil is heterogeneous at all spatial scales. However, little data are available to allow quantification of these heterogeneities at the field scale or larger. In this study, we investigated the spatial patterns of soil properties, hydrologic state variables, and tracer breakthrough curves (BTCs) at the field scale for the inert solute transport under a steady-state irrigation rate which produced near-saturated conditions. Sixty-five undisturbed soil columns approximately 20 cm in height and diameter were sampled from the loamy topsoil of an agricultural field site in Silstrup (Denmark) at a sampling distance of approximately 15 m (with a few exceptions), covering an area of approximately 1 ha (60 m × 165 m). For 64 of the 65 investigated soil columns, we observed BTC shapes indicating a strong preferential transport. The strength of preferential transport was positively correlated with the bulk density and the degree of water saturation. The latter suggests that preferential macropore transport was the dominating transport process. Increased bulk densities were presumably related with a decrease in near-saturated hydraulic conductivities and as a consequence to larger water saturation and the activation of larger macropores. Our study provides further evidence that it should be possible to estimate solute transport properties from soil properties such as soil texture or bulk density. We also demonstrated that estimation approaches established for the column scale have to be upscaled when applied to the field scale or larger.

Synchrotron SAXS Studies of Nanostructured Materials and Colloidal Solutions: A Review

Directory of Open Access Journals (Sweden)

Craievich A.F.

2002-01-01

Full Text Available Structural characterisations using the SAXS technique in a number of nanoheterogeneous materials and liquid solutions are reviewed. The studied systems are protein (lysozyme/water solutions, colloidal ZnO particles/water sols, nanoporous NiO-based xerogels, hybrid organic-inorganic siloxane-PEG and PPG nanocomposites and PbTe semiconductor nanocrystals embedded in a glass matrix. These investigations also focus on the transformations of time-varying structures and on structural changes related to variations in temperature and composition. The reviewed investigations aim at explaining the unusual and often interesting properties of nanostructured materials and solutions. Most of the reported studies were carried out using the SAXS beamline at the National Synchrotron Light Laboratory (LNLS, Campinas, Brazil.

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

International Nuclear Information System (INIS)

Regazzoni, A.E.

1984-01-01

The formation of Fe 3 O 4 particles in aqueous media and the properties of the Fe 3 O 4 /aqueous solution interface are studied. This system is of particular interest in nuclear reactor chemistry, since Fe 3 O 4 was identified as the main component of the corrosion products of nuclear power plants cooled with pressurized water, of the Atucha I and II, and Embalse type. Four methods for the synthesis of Fe 3 O 4 are described: a) controlled oxidation of Fe(OH) 2 in the presence of NaNO 3 at 25 deg C; b) controlled oxidation of Fe(OH) 2 in the presence of NaNO 3 and N 2 H 4 and at 100 deg C; c) alkalinization of a F 2+ and Fe 3+ solutions at 80 deg C; d) simultaneous oxidation and alkalinization of a Fe 2+ . The interfacial properties of Fe 3 O 4 particles suspended in aqueous solutions of indifferent electrolytes are described. These properties are essential for the activity transport associated with the corrosion products. Finally, the adsorption of H 3 BO 3 , Hsub(n)PO 4 sup(n-3) and n Co(II) in the Fe 3 O 4 /solution interface at 30 deg C. It is concluded that the adsorbed species are chemically bonded to surface metal ions. (M.E.L.) [es

The immiscible aqueous solutions of alkyl phosphates. Study for the purpose of uranium extraction from phosphoric acid solutions

International Nuclear Information System (INIS)

Mauborgne, Bernard

1979-01-01

Systems of immiscible aqueous solutions composed by a phase rich in mineral salt and by another phase almost totally containing an organic salt, have been studied for years, with quaternary ammonium salts with an organic cation. The objective of this research is to study systems symmetric to the previous ones, i.e. with organic anions such as alkyl phosphates, and then to try to understand mechanisms of extraction of metals in these environments. Based on properties of immiscible aqueous solutions, an original three-phase process of liquid-liquid extraction has been developed, and is used to separate uranium in phosphoric acids with better performance than the existing industrial processes [fr

Influence of lanthanum on the physico-chemical properties of solid solutions GeS0.5Se0.5

International Nuclear Information System (INIS)

Murquzov, M.I.; Alekperov, A.S.; Bayramov, R.B.

2010-01-01

By the methods of physical-chemical analysis (X-ray, MSA, as well as measurement of microhardness and density determination) the influence of La on the physico-chemical properties of solid solutions (GeS 0 .5Se 0 .5) 1 -x(La) x was studied and its microdiagram was plotted. At room temperature the GeS 0 .5Se 0 .5 based solid solution extent 4 at. percent of La. The dependence of lanthane microhardness was studied

Thermal and volumetric properties of complex aqueous electrolyte solutions using the Pitzer formalism - The PhreeSCALE code

Science.gov (United States)

Lach, Adeline; Boulahya, Faïza; André, Laurent; Lassin, Arnault; Azaroual, Mohamed; Serin, Jean-Paul; Cézac, Pierre

2016-07-01

The thermal and volumetric properties of complex aqueous solutions are described according to the Pitzer equation, explicitly taking into account the speciation in the aqueous solutions. The thermal properties are the apparent relative molar enthalpy (Lϕ) and the apparent molar heat capacity (Cp,ϕ). The volumetric property is the apparent molar volume (Vϕ). Equations describing these properties are obtained from the temperature or pressure derivatives of the excess Gibbs energy and make it possible to calculate the dilution enthalpy (∆HD), the heat capacity (cp) and the density (ρ) of aqueous solutions up to high concentrations. Their implementation in PHREEQC V.3 (Parkhurst and Appelo, 2013) is described and has led to a new numerical tool, called PhreeSCALE. It was tested first, using a set of parameters (specific interaction parameters and standard properties) from the literature for two binary systems (Na2SO4-H2O and MgSO4-H2O), for the quaternary K-Na-Cl-SO4 system (heat capacity only) and for the Na-K-Ca-Mg-Cl-SO4-HCO3 system (density only). The results obtained with PhreeSCALE are in agreement with the literature data when the same standard solution heat capacity (Cp0) and volume (V0) values are used. For further applications of this improved computation tool, these standard solution properties were calculated independently, using the Helgeson-Kirkham-Flowers (HKF) equations. By using this kind of approach, most of the Pitzer interaction parameters coming from literature become obsolete since they are not coherent with the standard properties calculated according to the HKF formalism. Consequently a new set of interaction parameters must be determined. This approach was successfully applied to the Na2SO4-H2O and MgSO4-H2O binary systems, providing a new set of optimized interaction parameters, consistent with the standard solution properties derived from the HKF equations.

Mechanical properties of regular porous biomaterials made from truncated cube repeating unit cells: Analytical solutions and computational models.

Science.gov (United States)

Hedayati, R; Sadighi, M; Mohammadi-Aghdam, M; Zadpoor, A A

2016-03-01

Additive manufacturing (AM) has enabled fabrication of open-cell porous biomaterials based on repeating unit cells. The micro-architecture of the porous biomaterials and, thus, their physical properties could then be precisely controlled. Due to their many favorable properties, porous biomaterials manufactured using AM are considered as promising candidates for bone substitution as well as for several other applications in orthopedic surgery. The mechanical properties of such porous structures including static and fatigue properties are shown to be strongly dependent on the type of the repeating unit cell based on which the porous biomaterial is built. In this paper, we study the mechanical properties of porous biomaterials made from a relatively new unit cell, namely truncated cube. We present analytical solutions that relate the dimensions of the repeating unit cell to the elastic modulus, Poisson's ratio, yield stress, and buckling load of those porous structures. We also performed finite element modeling to predict the mechanical properties of the porous structures. The analytical solution and computational results were found to be in agreement with each other. The mechanical properties estimated using both the analytical and computational techniques were somewhat higher than the experimental data reported in one of our recent studies on selective laser melted Ti-6Al-4V porous biomaterials. In addition to porosity, the elastic modulus and Poisson's ratio of the porous structures were found to be strongly dependent on the ratio of the length of the inclined struts to that of the uninclined (i.e. vertical or horizontal) struts, α, in the truncated cube unit cell. The geometry of the truncated cube unit cell approaches the octahedral and cube unit cells when α respectively approaches zero and infinity. Consistent with those geometrical observations, the analytical solutions presented in this study approached those of the octahedral and cube unit cells when �

Comparative study of polypyrrole films electrosynthesized in alkaline and acid solutions

International Nuclear Information System (INIS)

Lehr, I.L.; Quinzani, O.V.; Saidman, S.B.

2009-01-01

The influence of the pH of electropolymerization solutions on the properties of polypyrrole films has been studied using potentiodynamic techniques and faradaic impedance spectroscopy. Scanning electron microscopy (SEM), IR and Raman spectroscopies, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were also used for products characterization. Results indicate that, contrary to what happen with the polymer electrogenerated in acid solutions, the films prepared in alkaline media are stable and present good electrochemical activity in basic solutions. Possible explanations for the observed differences are discussed and it is proposed that the pH of electropolymerization medium directly affects chains organization. Electrosynthesis in solutions of increased basicity results in a more compact and closed polymer structure.

Synthesis and photoluminescence properties of CaSixOy:Tb3+ phosphors prepared using solution-combustion method

CSIR Research Space (South Africa)

Dejene, FB

2011-07-01

Full Text Available Effect of Tb3+ ion concentrations on the structural and persistence luminescence properties of CaSixOy:Tb3+ crystals were evaluated using powders grown by the solution combustion technique. The XRD study indicates the change of phase from CaSiO3...

Dielectric and Piezoelectric Properties of PZT Composite Thick Films with Variable Solution to Powder Ratios.

Science.gov (United States)

Wu, Dawei; Zhou, Qifa; Shung, Koping Kirk; Bharadwaja, Srowthi N; Zhang, Dongshe; Zheng, Haixing

2009-05-08

The use of PZT films in sliver-mode high-frequency ultrasonic transducers applications requires thick, dense, and crack-free films with excellent piezoelectric and dielectric properties. In this work, PZT composite solutions were used to deposit PZT films >10 μm in thickness. It was found that the functional properties depend strongly on the mass ratio of PZT sol-gel solution to PZT powder in the composite solution. Both the remanent polarization, P(r), and transverse piezoelectric coefficient, e(31,) (f), increase with increasing proportion of the sol-gel solution in the precursor. Films prepared using a solution-to-powder mass ratio of 0.5 have a remanent polarization of 8 μC/cm(2), a dielectric constant of 450 (at 1 kHz), and e(31,) (f) = -2.8 C/m(2). Increasing the solution-to-powder mass ratio to 6, the films were found to have remanent polarizations as large as 37 μC/cm(2), a dielectric constant of 1250 (at 1 kHz) and e(31,) (f) = -5.8 C/m(2).

Influence of starch origin on rheological properties of concentrated aqueous solutions

Directory of Open Access Journals (Sweden)

Stojanović Željko P.

2011-01-01

Full Text Available The rheological properties of corn and potato starch concentrated aqueous solutions were investigated at 25ºC. The starches were previously dispersed in water and the solutions were obtained by heating of dispersions at 115-120ºC for 20 minutes. The solutions of potato starch were transparent, while the corn starch solutions were opalescent. The results of dynamic mechanical measurements showed that the values of viscosity, h, storage modulus, G′, and loss modulus, G″, of the corn starch solutions increased with the storage time. This phenomenon was not observed for the potato starch solutions. It was assumed that the increase of h, G′ and G″ is the result of starch solutions retrogradation. The potato starch solutions retrogradation did not occur probably because of the phosphates presence. The viscosity of 2 mass % corn starch solution is less than the viscosity of 2 mass % potato starch solution. By increasing the concentration of corn starch solution the gel with elastic behavior was formed. The corn starch solutions formed gel as early as at 4 mass % concentration, while potato starch solutions achieved the gel state at the concentration of 5 mass %. The value of exponent m (G′ and G″ µ wm during the transition of potato starch solutions to gel is 0.414, which gives the fractal dimensions for corn starch of 2.10. The obtained value of fractal dimension corresponds to slow aggregation. The corn starch solutions with the starch concentrations higher than 4 mass % form weak gels. For these solutions the values of modulus in rubber plateau were determined. It was found that the modulus in rubber plateau increased with the concentration by the exponent of 4.36. Such high exponent value was obtained in the case when the tridimensional network is formed, i.e. when supermolecular structures like associates or crystal domains are formed.

Effect of sodium carbonate solution on self-setting properties of tricalcium silicate bone cement.

Science.gov (United States)

Zhiguang Huan; Jiang Chang

2008-11-01

In this study, the effects of sodium carbonate (Na(2)CO(3) ) solution with different concentrations (10, 15, 20, and 25 wt%) as liquid phase on the setting time and compressive strength of tricalcium silicate bone cements are investigated. The in vitro bioactivity and degradability of the resultant Ca(3)SiO(5)-Na(2)CO(3) solution paste was also studied. The results indicate that as the concentration of Na(2)CO(3) solution varies from 0 to 25 wt%, the initial and final setting time of the cement decrease significantly from 90 to 20 min and from 180 to 45 min, respectively. After setting for 24 h, the compressive strength of Ca(3)SiO(5)-Na(2)CO(3) solution paste reaches 5.1 MPa, which is significantly higher than that of Ca( 3)SiO(5)-water cement system. The in vitro bioactivity of the cements is investigated by soaking in simulated body fluid (SBF) for 7 days. The results show that the Ca(3)SiO(5)-Na(2)CO( 3) solution bone cement has a good bioactivity and can degrade in Ringer's solution. The results indicate that Na(2)CO(3) solution as a liquid phase significantly improves the self-setting properties of Ca( 3)SiO(5) cement as compared to water. The Ca(3)SiO( 5) cement paste prepared using Na(2)CO(3) solution shows good bioactivity and moderate degradability, and the Ca(3)SiO( 5)-Na(2)CO(3) solution system may be used as degradable and bioactive bone defect filling materials.

Mechanical properties of calcium phosphate cements obtained by solution combustion synthesis

Energy Technology Data Exchange (ETDEWEB)

Volkmer, Tiago M.; Barreiro, Oscar; Souza, Vania Caldas; Santos, Luis Alberto dos, E-mail: tiagovolkmer@gmail.com, E-mail: oscarbafer@hotmail.com, E-mail: vania.souza@ufrgs.br, E-mail: luis.santos@ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Laboratorio de Biomateriais

2009-07-01

Bioceramics based on calcium phosphates, especially hydroxyapatite and tricalcium phosphates (TCP) are the most used biomaterials as bone substitutes. The objective of this work is to evaluate the mechanical properties of α-tricalcium phosphate (α-TCP) synthesized by the solution combustion method. The solution combustion synthesis (SCS) can be considered as faster and simpler as other methods, furthermore it allows the obtainment of high purity α-TCP. In the calcium phosphates (CPC), α-TCP reacts with water forming needle like HA, which restrain the movement of grains, increasing mechanical resistance. In the present paper the influence of particle size on mechanical properties of α-TCP cements were evaluated. The α-TCP powder were characterized by XRD, TEM, BET and laser diffraction to asses particle size while the CPC bodies by SEM, Arquimedes method and compression tests. Increasing the milling time, the particle size decreases, resulting in samples with less porosity and consequently with higher compression resistance. (author)

Gammaradiation effect on spectral properties of oxyhemoglobin solutions of different pH in the presence of serotonin

International Nuclear Information System (INIS)

Artyukhov, V.G.

1979-01-01

Changes in spectral properties of oxyhemoglobin solutions (pH 3 to 12) of mice exposed to gammaradiation (6000R) in the presence of serotonin have been studied. It was established that serotonin (5x10 -5 M) exerts a radioprotective effect in respect of oxyhemoglobin solutions of pH 5 to 9. Serotonin fails to protect protein in the presence of catalase (1x10 -6 M). It is stated that the process of formation of hydrogen peroxide/serotonin complex appreciably contributes to the protective action of the radioprotective agent in respect of gammairradiated oxyhemoglobin solutions

Study of the physicochemical properties of the interface between titanium dioxide and various aqueous solutions

International Nuclear Information System (INIS)

Mazilier, C.

1988-01-01

The aim of this work is the study of ion exchange capacity of titanium dioxide in view of high temperature water purification and radioactive effluent processing because of its resistance to heat and radiations. Titanium dioxide is obtained by alkaline hydrolysis of an aqueous solution of Ti (IV) and is characterized by analytical physical chemistry methods. Interface between Ti0 2 and simple aqueous solutions (electrolytes) is more particularly studied by potentiometry [fr

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

Synchrotron SAXS studies of nanostructured materials and colloidal solutions: a review

International Nuclear Information System (INIS)

Craievich, A.F.

2002-01-01

Structural characterisations using the SAXS technique in a number of nano heterogeneous materials and liquid solutions are reviewed. The studied systems are protein (lysozyme)/water solutions, colloidal Zn O particles/water sols, nano porous Ni O-based xerogels, hybrid organic-inorganic siloxane-PEG and PPG nano composites and PbTe semiconductor nano crystals embedded in a glass matrix. These investigations also focus on the transformations of time-varying structures and on structural changes related to variations in temperature and composition. The reviewed investigations aim at explaining the unusual and often interesting properties of nano structured materials and solutions. Most of the reported studies were carried out using the SAXS beamline at the National Synchrotron Light Laboratory (LNLS), Campinas, Brazil.(author)

A Study on Anti – Fouling Behaviour and Mechanical Properties of PVA/Chitosan/TEOS Hybrid membrane in The Treatment of Copper Solution

Science.gov (United States)

Sulaiman, N. A.; Kassim Shaari, N. Z.; Rahman, N. Abdul

2018-05-01

In a wastewater treatment by using membrane filtration, fouling has been one of the major problems. In this study, the anti-fouling behaviour of the fabricated thin-film composite membrane were studied during the treatment of water containing copper ion. The membranes were prepared from a polymer blend of 2wt.% chitosan with 10 wt.% poly(vinyl alcohol) (PVA) and then it was cross – linked with tetraethylorthosilicate (TEOS) through sol-gel method. The membrane had been evaluated for its resistance against organic fouling where humic acid had been chosen as organic foulant model which represent the natural organic matter (NOM) in water or wastewater. The dead-end filtration experiments were carried out by using 50 ppm of copper solution with and without the presence of humic acid as feed solution, which was passed through two types of thin film composite membranes. The possible reversible fouling was evaluated by using relative flux decay (RFD) and relative flux recovery (RFR) calculations. The percentage of copper ion removal was evaluated by using Atomic Absorption Spectroscopy (AAS). Based on the results, with the presence of humic acid, the membrane incorporated with silica precursor (TEOS) showed lower flux decay (3%) and higher flux recovery (76%), which show that the formulated hybrid membrane possesses the anti fouling property. The same trend was observed in the mechanical properties of hybrid membrane, where the presence of TEOS has improved the tensile strength and flexibility of the membrane. Therefore, the fabricated thin film composite with the anti-fouling properties and good physical flexibility has potential to be used in the treatment of wastewater containing heavy metal as it could result in good saving in term of operational cost.

Effect of number and washing solutions on functional properties of surimi-like material from duck meat.

Science.gov (United States)

Ramadhan, Kurnia; Huda, Nurul; Ahmad, Ruzita

2014-02-01

Duck meat is less utilized than other meats in processed products because of limitations of its functional properties, including lower water holding capacity, emulsion stability, and higher cooking loss compared with chicken meat. These limitations could be improved using surimi technology, which consists of washing and concentrating myofibrillar protein. In this study, surimi-like materials were made from duck meat using two or three washings with different solutions (tap water, sodium chloride, sodium bicarbonate, and sodium phosphate buffer). Better improvement of the meat's functional properties was obtained with three washings versus two washings. Washing with tap water achieved the highest gel strength; moderate elevation of water holding capacity, pH, lightness, and whiteness; and left a small amount of fat. Washing with sodium bicarbonate solution generated the highest water holding capacity and pH and high lightness and whiteness values, but it resulted in the lowest gel strength. Processing duck meat into surimi-like material improves its functional properties, thereby making it possible to use duck meat in processed products.

Spectroscopic properties of vitamin E models in solution

Science.gov (United States)

Oliveira, L. B. A.; Colherinhas, G.; Fonseca, T. L.; Castro, M. A.

2015-05-01

We investigate the first absorption band and the 13C and 17O magnetic shieldings of vitamin E models in chloroform and in water using the S-MC/QM methodology in combination with the TD-DFT and GIAO approaches. The results show that the solvent effects on these spectroscopic properties are small but a proper description of the solvent shift for 17O magnetic shielding of the hydroxyl group in water requires the use of explicit solute-solvent hydrogen bonds. In addition, the effect of the replacement of hydrogen atoms by methyl groups in the vitamin E models only affects magnetic shieldings.

Influence of solution annealing on microstructure and mechanical properties of Maraging 300 steel

Energy Technology Data Exchange (ETDEWEB)

Lima Filho, Venceslau Xavier; Barros, Isabel Ferreira; Abreu, Hamilton Ferreira Gomes de, E-mail: venceslau@ifce.edu.br [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Departamento de Engenharia Metalurgica e Materiais. Laboratorio de Caracterizacao de Materiais, Metalurgia Fisica e Grupo de Pesquisa de Transformacao de Fase

2017-01-15

Maraging 300 belongs to a family of metallic materials with extremely high mechanical strength and good toughness. Some works have been published about aging temperatures that improve ultimate strength resistance with acceptable toughness levels in this steel family, where the prior austenite grain size obtained by different solution annealing temperature influence in the final mechanical properties. Solution annealing temperatures ranging from 860 °C to 1150 deg C and were kept constant until the aging temperature. These treatments were used in order to investigate their influence on the microstructure and mechanical properties of maraging steel 300, especially with regard to toughness. The characterization of the microstructure was performed by optical microscopy, scanning electron microscope (SEM) and X-ray diffraction (XRD). Mechanical properties were evaluated by Rockwell C hardness and Charpy impact tests. The results showed that there is a temperature range where one can get some improvement in toughness without a large loss of mechanical strength. (author)

Study of the changes in composition of ammonium diuranate with progress of precipitation, and study of the properties of ammonium diuranate and its subsequent products produced from both uranyl nitrate and uranyl fluoride solutions

Energy Technology Data Exchange (ETDEWEB)

Manna, Subhankar; Kumar, Raj; Satpati, Santosh K.; Roy, Saswati B. [Bhabha Atomic Research Centre, Trombay, Mumbai (India); Joshi, Jyeshtharaj B. [Dept. of Chemical Engineering, Institute of Chemical Technology, Mumbai (India)

2017-04-15

Uranium metal used for fabrication of fuel for research reactors in India is generally produced by magnesio-thermic reduction of UF{sub 4}. Performance of magnesio-thermic reaction and recovery and quality of uranium largely depends on properties of UF{sub 4}. As ammonium diuranate (ADU) is first product in powder form in the process flow-sheet, properties of UF{sub 4} depend on properties of ADU. ADU is generally produced from uranyl nitrate solution (UNS) for natural uranium metal production and from uranyl fluoride solution (UFS) for low enriched uranium metal production. In present paper, ADU has been produced via both the routes. Variation of uranium recovery and crystal structure and composition of ADU with progress in precipitation reaction has been studied with special attention on first appearance of the precipitate Further, ADU produced by two routes have been calcined to UO{sub 3}, then reduced to UO{sub 2} and hydroflorinated to UF{sub 4}. Effect of two different process routes of ADU precipitation on the characteristics of ADU, UO{sub 3}, UO{sub 2} and UF{sub 4} were studied here.

Influence of lanthanium atoms on the physico-chemical properties of GeS0,5Se0,5 solid solutions

International Nuclear Information System (INIS)

Murguzov, M.I.; Alakbarov, A.S.; Bayramov, R.B.

2010-01-01

By the methods of physical-chemical analysis (DTA, X-ray, MSA, as well as measurement of microhardness and density determination) the influence of La on the physico-chemical properties of solid solutions (GeS 0 ,5Se 0 ,5) 1 -x(La) x was studied and its microdiagram was plotted. At room temperature the GeS 0 ,5Se 0 ,5 based solid solid solution extent to 4 at. percent La. The dependence of lanthane microhardness was studied

Kinetic Uptake Studies of Powdered Materials in Solution

Directory of Open Access Journals (Sweden)

Mohamed H. Mohamed

2015-06-01

Full Text Available Challenges exist for the study of time dependent sorption processes for heterogeneous systems, especially in the case of dispersed nanomaterials in solvents or solutions because they are not well suited to conventional batch kinetic experiments. In this study, a comparison of batch versus a one-pot setup in two variable configurations was evaluated for the study of uptake kinetics in heterogeneous (solid/solution systems: (i conventional batch method; (ii one-pot system with dispersed adsorbent in solution with a semi-permeable barrier (filter paper or dialysis tubing for in situ sampling; and (iii one-pot system with an adsorbent confined in a semi-permeable barrier (dialysis tubing or filter paper barrier with ex situ sampling. The sorbent systems evaluated herein include several cyclodextrin-based polyurethane materials with two types of phenolic dyes: p-nitrophenol and phenolphthalein. The one-pot kinetics method with in situ (Method ii or ex situ (Method iii sampling described herein offers significant advantages for the study of heterogeneous sorption kinetics of highly dispersed sorbent materials with particles sizes across a range of dimensions from the micron to nanometer scale. The method described herein will contribute positively to the development of advanced studies for heterogeneous sorption processes where an assessment of the relative uptake properties is required at different experimental conditions. The results of this study will be advantageous for the study of nanomaterials with significant benefits over batch kinetic studies for a wide range of heterogeneous sorption processes.

Study of influence of fuel on dielectric and ferroelectric properties of bismuth titanate ceramics synthesized using solution based combustion technique

International Nuclear Information System (INIS)

Subohi, Oroosa; Malik, M M; Kurchania, Rajnish; Kumar, G S

2015-01-01

The effect of fuel characteristics on the processing and properties of bismuth titanate (BIT) ceramics obtained by solution combustion route using different fuels are reported in this paper. Dextrose, urea and glycine were used as fuel in this study. The obtained bismuth titanate ceramics were characterized by using XRD, SEM at different stages of sample preparation. It was observed that BIT obtained by using dextrose as fuel shows higher dielectric constant and higher remnant polarization due to smaller grain size and lesser c-axis growth as compared to the samples with urea and glycine as fuel. The electrical behavior of the samples with respect to temperature and frequency was also investigated to understand relaxation phenomenon. (paper)

Biocorrosion properties of antibacterial Ti-10Cu sintered alloy in several simulated biological solutions.

Science.gov (United States)

Liu, Cong; Zhang, Erlin

2015-03-01

Ti-10Cu sintered alloy has shown strong antibacterial properties against S. aureus and E. coli and good cell biocompatibility, which displays potential application in dental application. The corrosion behaviors of the alloy in five different simulated biological solutions have been investigated by electrochemical technology, surface observation, roughness measurement and immersion test. Five different simulated solutions were chosen to simulate oral condition, oral condition with F(-) ion, human body fluids with different pH values and blood system. It has been shown that Ti-10Cu alloy exhibits high corrosion rate in Saliva pH 3.5 solution and Saliva pH 6.8 + 0.2F solution but low corrosion rate in Hank's, Tyrode's and Saliva pH 6.8 solutions. The corrosion rate of Ti-10Cu alloy was in a order of Hank's, Tyrode's, Saliva pH 6.8, Saliva-pH 3.5 and Saliva pH 6.8 + 0.2F from slow to fast. All results indicated acid and F(-) containing conditions prompt the corrosion reaction of Ti-Cu alloy. It was suggested that the Cu ion release in the biological environments, especially in the acid and F(-) containing condition would lead to high antibacterial properties without any cell toxicity, displaying wide potential application of this alloy.

Properties of gases, liquids, and solutions principles and methods

CERN Document Server

Mason, Warren P

2013-01-01

Physical Acoustics: Principles and Methods, Volume ll-Part A: Properties of Gases, Liquids, and Solutions ponders on high frequency sound waves in gases, liquids, and solids that have been proven as effective tools in examining the molecular, domain wall, and other types of motions. The selection first offers information on the transmission of sound waves in gases at very low pressures and the phenomenological theory of the relaxation phenomena in gases. Topics include free molecule propagation, phenomenological thermodynamics of irreversible processes, and simultaneous multiple relaxation pro

Dielectric properties of lead orthovanadate and orthophosphate and some solid solutions on theirs basis

International Nuclear Information System (INIS)

Dudnik, E.F.; Sinyakov, E.V.; Gene, V.V.

1977-01-01

The dielectric properties of the monocrystals of the ferroelastics Pb 3 (PO 4 ) 2 and Pb 3 (VO 4 ) 2 were investigated. The dependencies of dielectric permeability and double refraction upon temperature were measured. The domain structure and the effect of pressure upon it were studied. The influence of BaO, CaO and Cr 2 O 3 additions upon the properties of Pb 3 (V 4 ) 2 monocrystals and upon the system of monocrystalline solid solutions of Pb 3 (VO 4 ) 2 - Pb 3 (PO 4 ) 2 was also examined. Similar to the case of usual segnetoelectrics, introduction of additions into segnetoelastic crystals was found to lead to spreading of the phase transition

Carbohydrate modified polysiloxanes, 3 - Solution properties of carbohydrate-polysiloxane conjugates in toluene

NARCIS (Netherlands)

Loos, Katja; Jonas, Gerd; Stadler, Reimund

2001-01-01

High molecular weight poly(hydromethyl-co-dimethyl) siloxanes containing 0.6 and 3 mol-% of Si-H units are polar functionalized by the addition of various mono-, di- and oligosaccharides. Due to the hydrogen bond interaction between the carbohydrate moieties, the solution properties are strongly

Redox properties of phenosafranine at zeolite-modified electrodes-Effect of surface modification and solution pH

International Nuclear Information System (INIS)

Easwaramoorthi, S.; Natarajan, P.

2008-01-01

Redox properties of cationic dye phenosafranine (3,7-diamino-5-phenylphenazenium chloride) (PS + ) were studied at zeolite-modified electrodes using Zeolite-Y and NaZSM-5. The peak current and peak potential of phenosafranine-adsorbed zeolite were found to be influenced by the pH of the electrolyte solution. Observation of a second redox couple is suggested to be due to formation of new species at low concentration from the reduced phenosafranine at the zeolite-modified electrodes. Titanium dioxide nanoparticles encapsulated in the cavities of the zeolite or anchored on the external surface of the zeolite do not seem to affect the redox properties of adsorbed PS + . When the cyclic voltammograms are recorded immediately after the electrode is immersed into the solution, the redox potential of PS + is found to be sensitive to the nature of the zeolite surface. The peak potential shifts towards positive region under continuous cycles as the surface hydroxyl groups get protonated in acidic electrolyte solution thereby forcing the movement of dye molecules from the zeolite surface to the zeolite electrode solution interface. The electron transfer rate constants for the adsorbed dye at the electrode are calculated to be 2.5 ± 0.2 s -1 and 3.5 ± 0.2 s -1 for the zeolite-Y electrode and the ZSM-5 electrode, respectively by the Laviron equation

Decay Properties of Axially Symmetric D-Solutions to the Steady Navier-Stokes Equations

Science.gov (United States)

Weng, Shangkun

2018-03-01

We investigate the decay properties of smooth axially symmetric D-solutions to the steady Navier-Stokes equations. The achievements of this paper are two folds. One is improved decay rates of u_{θ } and \

Solid state synthesis, crystal growth and optical properties of urea and p-chloronitrobenzene solid solution

Energy Technology Data Exchange (ETDEWEB)

Rai, R.N., E-mail: rn_rai@yahoo.co.in [Department of Chemistry, Centre of Advanced Study, Banaras Hindu University, Varanasi 221005 (India); Kant, Shiva; Reddi, R.S.B. [Department of Chemistry, Centre of Advanced Study, Banaras Hindu University, Varanasi 221005 (India); Ganesamoorthy, S. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamilnadu (India); Gupta, P.K. [Laser Materials Development & Devices Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)

2016-01-15

Urea is an attractive material for frequency conversion of high power lasers to UV (for wavelength down to 190 nm), but its usage is hindered due to its hygroscopic nature, though there is no alternative organic NLO crystal which could be transparent up to 190 nm. The hygroscopic character of urea has been modified by making the solid solution (UCNB) of urea (U) and p-chloronitrobenzene (CNB). The formation of the solid solution of CNB in U is explained on the basis of phase diagram, powder XRD, FTIR, elemental analysis and single crystal XRD studies. The solubility of U, CNB and UCNB in ethanol solution is evaluated at different temperatures. Transparent single crystals of UCNB are grown from its saturated solution in ethanol. Optical properties e.g., second harmonic generation (SHG), refractive index and the band gap for UCNB crystal were measured and their values were compared with the parent compounds. Besides modification in hygroscopic nature, UCNB has also shown the higher SHG signal and mechanical hardness in comparison to urea crystal. - Highlights: • The hygroscopic character of urea was modified by making the solid solution • Solid solution formation is support by elemental, powder- and single crystal XRD • Crystal of solid solution has higher SHG signal and mechanical stability. • Refractive index and band gap of solid solution crystal have determined.

Impact of an Alkaline Solution on the Chemistry, Mineralogy, and Sorption Properties of a Typic Rhodudult Soil

Directory of Open Access Journals (Sweden)

Jaqueline Alves de Almeida Calábria

2017-11-01

Full Text Available Abstract The preferred option for disposal of short-lived low and intermediate level radioactive wastes is a near surface disposal facility in which soil is one of the barriers that avoid radionuclide migration outside the controlled area. For construction of that kind of facility, concrete is widely used, and its interaction with water induces its degradation, resulting in a high pH solution. The alkaline solution may affect the near-field environment of radioactive waste repositories, including the soil, promoting mineralogical alterations that result in significant changes in key properties of materials, compromising their performance as safety components. In this study, a sample of a Brazilian Typic Rhodudult soil, previously investigated concerning its performance for Cs sorption, was subjected to interaction with the alkaline solution for 24 h and for 7, 14, and 28 days in order to evaluate the impact on its chemical, mineralogical, and sorption properties. X-ray diffraction (XRD, energy dispersive X-ray spectroscopy (EDX, atomic absorption spectrometry (AAS, scanning electron microscopy (SEM, and electron microprobe analysis were performed before and after each alteration period. Results indicated dissolution of minerals, such as kaolinite and quartz, associated with incorporation of K and Ca from the alkaline solution, likely resulting in the formation of hydrated calcium silicate phases (CSH, which are expected to be worse sorbents for alkaline elements (e.g., Cs than the original minerals. The Kd values for Cs in the altered samples also decreased according to the alteration period, demonstrating that alkaline interaction effectively modifies the soil sorption properties for Cs.

NONSTANDARD PROBLEMS IN STUDYING THE PROPERTIES FUNCTIONS.

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V. I. Kuzmich

2010-06-01

Full Text Available In this paper we consider two non-standard problems that may be offered to students for independent solution in the study of fundamental properties of functions in the course of mathematical analysis. These tasks are wearing creativity and contribute to a better understanding of students to concepts such as monotonicity and continuity of the function.

Effect of Different Seed Solutions on the Morphology and Electrooptical Properties of ZnO Nanorods

OpenAIRE

Kashif, M.; Hashim, U.; Ali, M. E.; Usman Ali, Syed M.; Rusop, M.; Ibupoto, Zafar Hussain; Willander, Magnus

2012-01-01

The morphology and electrooptical properties of ZnO nanorods synthesized on monoethanolamine-based seed layer and KOH-based seed layer were compared. The seed solutions were prepared in monoethanolamine in 2-methoxyethanol and potassium hydroxide in methanol, respectively. Zinc acetate dihydrate was as a common precursor in both solutions. The nanorod-ZnOs were synthesized via the spin coating of two different seed solutions on silicon substrates followed by their hydrothermal growth. The sca...

Ions, solutes and solvents, oh my!

Energy Technology Data Exchange (ETDEWEB)

Kemp, Daniel David [Iowa State Univ., Ames, IA (United States)

2009-08-01

Modern methods in ab initio quantum mechanics have become efficient and accurate enough to study many gas-phase systems. However, chemists often work in the solution phase. The presence of solvent molecules has been shown to affect reaction mechanisms1, lower reaction energy barriers2, participate in energy transfer with the solute3 and change the physical properties of the solute4. These effects would be overlooked in simple gas phase calculations. Careful study of specific solvents and solutes must be done in order to fully understand the chemistry of the solution phase. Water is a key solvent in chemical and biological applications. The properties of an individual water molecule (a monomer) and the behavior of thousands of molecules (bulk solution) are well known for many solvents. Much is also understood about aqueous microsolvation (small clusters containing ten water molecules or fewer) and the solvation characteristics when bulk water is chosen to solvate a solute. However, much less is known about how these properties behave as the cluster size transitions from the microsolvated cluster size to the bulk. This thesis will focus on species solvated with water clusters that are large enough to exhibit the properties of the bulk but small enough to consist of fewer than one hundred solvent molecules. New methods to study such systems will also be presented.

Bayesian estimation of the hydraulic and solute transport properties of a small-scale unsaturated soil column

Directory of Open Access Journals (Sweden)

Moreira Paulo H. S.

2016-03-01

Full Text Available In this study the hydraulic and solute transport properties of an unsaturated soil were estimated simultaneously from a relatively simple small-scale laboratory column infiltration/outflow experiment. As governing equations we used the Richards equation for variably saturated flow and a physical non-equilibrium dual-porosity type formulation for solute transport. A Bayesian parameter estimation approach was used in which the unknown parameters were estimated with the Markov Chain Monte Carlo (MCMC method through implementation of the Metropolis-Hastings algorithm. Sensitivity coefficients were examined in order to determine the most meaningful measurements for identifying the unknown hydraulic and transport parameters. Results obtained using the measured pressure head and solute concentration data collected during the unsaturated soil column experiment revealed the robustness of the proposed approach.

Cheminformatics Modeling of Amine Solutions for Assessing their CO2 Absorption Properties.

Science.gov (United States)

Kuenemann, Melaine A; Fourches, Denis

2017-07-01

As stricter regulations on CO 2 emissions are adopted worldwide, identifying efficient chemical processes to capture and recycle CO 2 is of critical importance for industry. The most common process known as amine scrubbing suffers from the lack of available amine solutions capable of capturing CO 2 efficiently. Tertiary amines characterized by low heats of reaction are considered good candidates but their absorption properties can significantly differ from one analogue to another despite high structural similarity. Herein, after collecting and curating experimental data from the literature, we have built a modeling set of 41 amine structures with their absorption properties. Then we analyzed their chemical composition using molecular descriptors and non-supervised clustering. Furthermore, we developed a series of quantitative structure-property relationships (QSPR) to assess amines' CO 2 absorption properties from their structural characteristics. These models afforded reasonable prediction performances (e. g., Q 2 LOO =0.63 for CO 2 absorption amount) even though they are solely based on 2D chemical descriptors and individual machine learning techniques (random forest and neural network). Overall, we believe the chemical analysis and the series of QSPR models presented in this proof-of-concept study represent new knowledge and innovative tools that could be very useful for screening and prioritizing hypothetical amines to be synthesized and tested experimentally for their CO 2 absorption properties. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

Eosin Removal Properties of Organo-Local Clay from Aqueous Solution

OpenAIRE

Rawan Al-Faze; Fethi Kooli

2014-01-01

Local clay from Al-Madinah Al-Munawwarah was modified by a solution of cetyltrimethylammonium bromide (C16TMABr) at different initial concentrations. The organoclays were characterized by PXRD, TGA, FTIR and N2 adsorption isotherms. The ability of these samples to remove the dye eosin is evaluated. The removal properties of organoclays were dependent on the content of C16TMA cations, the initial concentrations of eosin, temperature of the removal process, the mass of the used organoclays. T...

Inorganic polymers from laterite using activation with phosphoric acid and alkaline sodium silicate solution: Mechanical and microstructural properties

Energy Technology Data Exchange (ETDEWEB)

Lassinantti Gualtieri, Magdalena, E-mail: magdalena.gualtieri@unimore.it [Dipartimento di Ingegneria " Enzo Ferrari" , Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy); Romagnoli, Marcello [Dipartimento di Ingegneria " Enzo Ferrari" , Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy); Pollastri, Simone; Gualtieri, Alessandro F. [Dipartimento di Scienze Chimiche e Geologiche, Università degli studi di Modena e Reggio Emilia, Via S. Eufemia 19I, I-41121 Modena (Italy)

2015-01-15

Geopolymers from laterite, an iron-rich soil available in developing countries, have great potential as building materials. In this work, laterite from Togo (Africa) was used to prepare geopolymers using both phosphoric acid and alkaline sodium silicate solution. Microstructural properties were investigated by scanning electron microscopy, X-ray powder diffraction and mercury porosimetry, whereas thermal properties were evaluated by thermal analyses. The local environment of iron was studied by X-ray Absorption Spectroscopy (XANES region). The mechanical properties were determined. Modulus of Rupture and Young's modulus fell in the ranges 3.3–4.5 MPa and 12–33 GPa, respectively, rendering the materials good candidates for construction purposes. Heating above 900 °C results in weight-gain, presumably due to iron redox reactions. X-ray Absorption Spectroscopy data evidence changes in the chemical and structural environments of iron following thermal treatment of geopolymers. These changes indicate interaction between the geopolymer structure and iron during heating, possibly leading to redox properties. -- Highlights: •Geopolymerization of laterite is promising for fabrication of building materials. •Both phosphoric acid and alkaline sodium silicate solution can be used for activation. •Thermally activated redox properties of the inorganic polymers were observed.

Inorganic polymers from laterite using activation with phosphoric acid and alkaline sodium silicate solution: Mechanical and microstructural properties

International Nuclear Information System (INIS)

Enzo Ferrari, Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy))" data-affiliation=" (Dipartimento di Ingegneria Enzo Ferrari, Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy))" >Lassinantti Gualtieri, Magdalena; Enzo Ferrari, Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy))" data-affiliation=" (Dipartimento di Ingegneria Enzo Ferrari, Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy))" >Romagnoli, Marcello; Pollastri, Simone; Gualtieri, Alessandro F.

2015-01-01

Geopolymers from laterite, an iron-rich soil available in developing countries, have great potential as building materials. In this work, laterite from Togo (Africa) was used to prepare geopolymers using both phosphoric acid and alkaline sodium silicate solution. Microstructural properties were investigated by scanning electron microscopy, X-ray powder diffraction and mercury porosimetry, whereas thermal properties were evaluated by thermal analyses. The local environment of iron was studied by X-ray Absorption Spectroscopy (XANES region). The mechanical properties were determined. Modulus of Rupture and Young's modulus fell in the ranges 3.3–4.5 MPa and 12–33 GPa, respectively, rendering the materials good candidates for construction purposes. Heating above 900 °C results in weight-gain, presumably due to iron redox reactions. X-ray Absorption Spectroscopy data evidence changes in the chemical and structural environments of iron following thermal treatment of geopolymers. These changes indicate interaction between the geopolymer structure and iron during heating, possibly leading to redox properties. -- Highlights: •Geopolymerization of laterite is promising for fabrication of building materials. •Both phosphoric acid and alkaline sodium silicate solution can be used for activation. •Thermally activated redox properties of the inorganic polymers were observed

Thermodynamic and structure-property study of liquid-vapor equilibrium for aroma compounds.

Science.gov (United States)

Tromelin, Anne; Andriot, Isabelle; Kopjar, Mirela; Guichard, Elisabeth

2010-04-14

Thermodynamic parameters (T, DeltaH degrees , DeltaS degrees , K) were collected from the literature and/or calculated for five esters, four ketones, two aldehydes, and three alcohols, pure compounds and compounds in aqueous solution. Examination of correlations between these parameters and the range values of DeltaH degrees and DeltaS degrees puts forward the key roles of enthalpy for vaporization of pure compounds and of entropy in liquid-vapor equilibrium of compounds in aqueous solution. A structure-property relationship (SPR) study was performed using molecular descriptors on aroma compounds to better understand their vaporization behavior. In addition to the role of polarity for vapor-liquid equilibrium of compounds in aqueous solution, the structure-property study points out the role of chain length and branching, illustrated by the correlation between the connectivity index CHI-V-1 and the difference between T and log K for vaporization of pure compounds and compounds in aqueous solution. Moreover, examination of the esters' enthalpy values allowed a probable conformation adopted by ethyl octanoate in aqueous solution to be proposed.

Myelography iodinated contrast media. I. Unraveling the atropisomerism properties in solution.

Science.gov (United States)

Fontanive, Luca; D'Amelio, Nicola; Cesàro, Attilio; Gamini, Amelia; Tavagnacco, Letizia; Paolantoni, Marco; Brady, John W; Maiocchi, Alessandro; Uggeri, Fulvio

2015-06-01

The present work reports a thorough conformational analysis of iodinated contrast media: iomeprol, iopamidol (the world's most utilized contrast agent), and iopromide. Its main aim is the understanding of the complex structural features of these atropisomeric molecules, characterized by the presence of many conformers with hindered rotations, and of the role of atropisomerism in the physicochemical properties of their aqueous solutions. The problem was tackled by using an extensive analysis of (13)C NMR data on the solutions of whole molecules and of simple precursors in addition to FT-IR investigation and molecular simulations. This analysis demonstrated that out of the many possible atropisomers, only a few are significantly populated, and their relative population is provided. The conformational analysis also indicated that the presence of a sterically hindered amidic bond, allowing a significant population of cis forms (E in iopromide and exo in iomeprol), may be the basis for an increased thermodynamic solubility of concentrated solutions of iomeprol.

Study of solute segregation at interfaces using Auger electron spectroscopy

International Nuclear Information System (INIS)

White, C.L.

1984-01-01

Interfacial segregation, often confined to within a few atomic distances of the interface, can strongly influence the processing and properties of metals and ceramics. The thinness of such solute-enriched regions can cause them to be particularly suitable for study using surface sensitive microanalytical techniques such as Auger electron spectroscopy (AES). The application of AES to studies of interfacial segregation in metals and ceramics is briefly reviewed, and several examples are presented. 43 references, 14 figures

Influence of Solution Properties and Process Parameters on the Formation and Morphology of YSZ and NiO Ceramic Nanofibers by Electrospinning

Directory of Open Access Journals (Sweden)

Gerard Cadafalch Gazquez

2017-01-01

Full Text Available The fabrication process of ceramic yttria-stabilized zirconia (YSZ and nickel oxide nanofibers by electrospinning is reported. The preparation of hollow YSZ nanofibers and aligned nanofiber arrays is also demonstrated. The influence of the process parameters of the electrospinning process, the physicochemical properties of the spinning solutions, and the thermal treatment procedure on spinnability and final microstructure of the ceramic fibers was determined. The fiber diameter can be varied from hundreds of nanometers to more than a micrometer by controlling the solution properties of the electrospinning process, while the grain size and surface roughness of the resulting fibers are mainly controlled via the final thermal annealing process. Although most observed phenomena are in qualitative agreement with previous studies on the electrospinning of polymeric nanofibers, one of the main differences is the high ionic strength of ceramic precursor solutions, which may hamper the spinnability. A strategy to control the effective ionic strength of precursor solutions is also presented.

Study of the thermoelectric properties of Pb{sub (1-x)} Sn{sub x} Te; Contribution a l'etude des proprietes thermoelectriques de solutions Pb{sub (1-x)}Sn{sub x} Te

Energy Technology Data Exchange (ETDEWEB)

Borde, D [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-04-15

The present work concerns the study of the electrical properties (thermoelectric power, electrical resistivity and Hall coefficient) of PbTe and SnTe crystals and of solid polycrystalline solutions of Pb{sub 1-x} Sn{sub x} Te (0.1 < x < 0.6) between 80 and 800 deg. K. From the temperature dependence of these properties and the effect of the addition, it has been possible to characterize the semiconductor nature of these solutions, and to approach their band structure; in particular the forbidden gap behaviour in these solutions has been analyzed and evidence for the existence of a double valence band has been obtained. (author) [French] Le present travail est relatif a l'etude des proprietes electriques, en particulier du pouvoir thermoelectrique de la resistivite electrique et du coefficient de Hall, de cristaux PbTe et SnTe, et de solutions solides polycristallines Pb{sub 1-x} Sn{sub x} Te (0,1 {<=} x {<=} 0,6) entre 80 et 800 deg. K. La variation de ces proprietes avec la temperature, ainsi que l'effet de l'addition de Sn sur celles-ci, ont permis de preciser le caractere semiconducteur de ces solutions, et contribue a la determination de leur structure de bandes, en particulier le comportement de la bande interdite dans ces solutions a ete analyse et l'existence d'une double bande de valence mise en evidence. (auteur)

Limit Properties of Solutions of Singular Second-Order Differential Equations

Directory of Open Access Journals (Sweden)

Weinmüller Ewa

2009-01-01

Full Text Available We discuss the properties of the differential equation , a.e. on , where , and satisfies the -Carathéodory conditions on for some . A full description of the asymptotic behavior for of functions satisfying the equation a.e. on is given. We also describe the structure of boundary conditions which are necessary and sufficient for to be at least in . As an application of the theory, new existence and/or uniqueness results for solutions of periodic boundary value problems are shown.

Investigation of Mechanical Properties and Fracture Simulation of Solution-Treated AA 5754

Science.gov (United States)

Kumar, Pankaj; Singh, Akhilendra

2017-10-01

In this work, mechanical properties and fracture toughness of as-received and solution-treated aluminum alloy 5754 (AA 5754) are experimentally evaluated. Solution heat treatment of the alloy is performed at 530 °C for 2 h, and then, quenching is done in water. Yield strength, ultimate tensile strength, impact toughness, hardness, fatigue life, brittle fracture toughness (K_{Ic} ) and ductile fracture toughness (J_{Ic} ) are evaluated for as-received and solution-treated alloy. Extended finite element method has been used for the simulation of tensile and fracture behavior of material. Heaviside function and asymptotic crack tip enrichment functions are used for modelling of the crack in the geometry. Ramberg-Osgood material model coupled with fracture energy is used to simulate the crack propagation. Fracture surfaces obtained from various mechanical tests are characterized by scanning electron microscopy.

Properties of altered soils by alkaline solution: contribution in the performance evaluation of repositories

International Nuclear Information System (INIS)

Calabria, Jaqueline Alves de Almeida

2015-01-01

evaluated samples (less than 20% after 10 days of equilibrium), being the best performance one, the nitosoil sample whose K_d values varied from 11.78 to 63.05 mL.g"-"1. In a subsequent step, the clay soil, was submitted to the alkaline solution interaction, in order to investigate possible alterations on the sorption properties and hydraulic conductivity of this soil. Using the sorption parameters, obtained from data fitted isotherms, the retardation factor, R, was estimated for the samples before and after the interaction. It was demonstrated that the alkaline alteration promotes damages to sorption properties of Cs, once the R became significantly smaller (about 1000 times) after the interaction. The hydraulic conductivity in turn increased slightly (3,91x10"-"8 cm.s"-"1 to 5,08 x 10"-"8 cm.s"-"1). It was concluded that these changes were due, mainly, to the dissolution of minerals present in the clay soil (kaolinite and quartz), associated with the incorporation of K and Ca from the alkaline solution, resulting, probably, in the formation of hydrated calcium silicate phases. Additionally, the effects of alkaline solution on the properties of a commercial bentonite were studied. Contrary to the clay soil, it was observed a gain in the sorption characteristics, with K_d (Cs) increasing from 760.05 mL.g"-"1to 1311.80 mL.g"-"1and Q_m_a_x from 36.32 mg.g"-"1to 52.13 mg.g"-"1, with the corresponding increase in the retardation coefficient, R. The dissolution of the clay minerals from the initial sample and the incorporation of Mg, K e Ca coming from the alkaline solution, generating smectite of different kinds, were considered as the main mineralogical changes responsible for the modifications in sorption parameters. The different behavior between the two evaluated samples, soil and bentonite, confirms that the nature and extension of changes observed, when mineral samples interact with alkaline solution, depend on the chemical/mineralogical composition of the solid material

Optical and photophysical properties of the chlorin-type photosensitizer photolon in aqueous solutions of different acidities

Science.gov (United States)

Bagrov, I. V.; Belousova, I. M.; Dadeko, A. V.; Krisko, T. K.; Kriukova, E. V.; Martynenko, I. V.; Savchenko, M. R.

2017-09-01

Photolon is a modern compound for fluorescence diagnostics and photodynamic therapy, which was relatively recently introduced into clinical practice. In the present work, we study its electronic-absorption spectra, fluorescence spectra (excited at different visible wavelengths), and fluorescence quantum yields. The characteristics are studied in aqueous solutions with pH 6.0-7.5 and compared under identical conditions with the corresponding characteristics of other chlorin- or porphyrin-type compounds (Photoditazin, Radachlorin, Dimegin) for photodynamic diagnostics and therapy. It is shown that the studied properties of Photolon are very close to those of Photoditazin and Radachlorin. At the same time, chlorin products are found to be more effective than Dimegin at pH 7.5, which is close to the pH of blood, while Dimegin is the most effective in solutions with lower pH, for example, in distilled water.

Dispersion of dielectric permittivity and magnetic properties of solid solution PZT–PFT

Directory of Open Access Journals (Sweden)

Skulski Ryszard

2015-09-01

Full Text Available In this paper we present the results of investigations into ceramic samples of solid solution (1-x(PbZr0.53Ti0.47O3- x(PbFe0.5Ta0.503 (i.e. (1-xPZT-xPFT with x = 0.25, 0.35 and 0.45. We try to find the relation between the character of dielectric dispersion at various temperatures and the composition of this solution. We also describe the magnetic properties of investigated samples. With increasing the content of PFT also mass magnetization and mass susceptibility increase (i.e. magnetic properties are more pronounced at every temperature. The temperature dependences of mass magnetization and re­ciprocal of mass susceptibility have similar runs for all the compositions. However, our magnetic investigations exhibit weak antiferromagnetic ordering instead of the ferromagnetic one at room temperature. We can also say that up to room tempera­ture any magnetic phase transition has not occurred. It may be a result of the conditions of the technological process during producing our PZT-PFT ceramics.

Surface properties of anatase TiO2 nanowire films grown from a fluoride-containing solution.

Science.gov (United States)

Berger, Thomas; Anta, Juan A; Morales-Flórez, Víctor

2013-06-03

Controlling the surface chemistry of nucleating seeds during wet-chemical synthesis allows for the preparation of morphologically well-defined nanostructures. Synthesis conditions play a key role in the surface properties, which directly affect the functional properties of the material. Therefore, it is important to establish post-synthesis treatments to facilitate the optimization of surface properties with respect to a specific application, without losing the morphological peculiarity of the nanostructure. We studied the surface properties of highly crystalline and porous anatase TiO2 nanowire (NW) electrodes, grown by chemical-bath deposition in fluoride-containing solutions, using a combined electrochemical and spectroscopic approach. As-deposited films showed low capacity for catechol adsorption and a poor photoelectrocatalytic activity for water oxidation. Mild thermal annealing at 200 °C resulted in a significant improvement of the electrode photoelectrocatalytic activity, whereas the bulk properties of the NWs (crystal structure, band-gap energy) remained unchanged. Enhancement of the functional properties of the material is discussed on the basis of adsorption capacity and electronic properties. The temperature-induced decrease of recombination centers, along with the concomitant increase of adsorption and reaction sites upon thermal annealing are called to be responsible for such improved performance. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A General Construction of Linear Differential Equations with Solutions of Prescribed Properties

Czech Academy of Sciences Publication Activity Database

Neuman, František

2004-01-01

Roč. 17, č. 1 (2004), s. 71-76 ISSN 0893-9659 R&D Projects: GA AV ČR IAA1019902; GA ČR GA201/99/0295 Institutional research plan: CEZ:AV0Z1019905 Keywords : construction of linear differential equations * prescribed qualitative properties of solutions Subject RIV: BA - General Mathematics Impact factor: 0.414, year: 2004

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

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....

COMPARATIVE STUDIES OF IMMUNOMODULATING PROPERTIES OF C HITOSAN AND ITS DERIVATIVES

Directory of Open Access Journals (Sweden)

L. A. Ivanushko

2007-01-01

Full Text Available Abstract. Comparative study was carried out, aiming to assess immunostimulatory properties of high-molecular chitosan (Ch-HM and its derivatives, i.e., low molecular weight chitosan (Ch-LM, N-3-hydroxymyristoyl (Ch-LM at a low acylation ratio, N-3-hydroxymyristoylchitooligosaccharides (N-acylchito-biose, -triose, -tetraose, N-, O-carboxyalkylchitosans (carboxymethyl, -ethyl, -propyl derivates. It was established, that the chemical modifications of chitosan influenced its biological activity. The derivatives of chitosan were found to have improved physical properties (good solubility in neutral and alkaline solutions, low viscosity in acidic solutions, good absorption from a gastrointestinal compartment, as compared with initial (high molecular weight chitosan formula. They possess immunomodulatory properties and may be regarded as promising substances for preparation of medical drugs and biologically active food additives (BAFA.

NIR spectroscopic properties of aqueous acids solutions.

Science.gov (United States)

Omar, Ahmad Fairuz; Atan, Hanafi; Matjafri, Mohd Zubir

2012-06-15

Acid content is one of the important quality attributes in determining the maturity index of agricultural product, particularly fruits. Despite the fact that much research on the measurement of acidity in fruits through non-destructive spectroscopy analysis at NIR wavelengths between 700 to 1,000 nm has been conducted, the same response towards individual acids is not well known. This paper presents NIR spectroscopy analysis on aqueous citric, tartaric, malic and oxalic solutions through quantitative analysis by selecting a set of wavelengths that can best be used to measure the pH of the solutions. The aquaphotomics study of the acid solutions has generated R² above 0.9 for the measurement of all acids. The most important wavelengths for pH are located at 918-925 nm and 990-996 nm, while at 975 nm for water.

Soil properties and preferential solute transport at the field scale

DEFF Research Database (Denmark)

Koestel, J K; Minh, Luong Nhat; Nørgaard, Trine

An important fraction of water flow and solute transport through soil takes place through preferential flow paths. Although this had been already observed in the nineteenth century, it had been forgotten by the scientific community until it was rediscovered during the 1970s. The awareness...... of the relevance of preferential flow was broadly re-established in the community by the early 1990s. However, since then, the notion remains widespread among soil scientists that the occurrence and strength of preferential flow cannot be predicted from measurable proxy variables such as soil properties or land...

Solution properties of targacanthin (water-soluble part of gum tragacanth exudate from Astragalus gossypinus).

Science.gov (United States)

Mohammadifar, Mohammad Amin; Musavi, Seyed Mohammad; Kiumarsi, Amir; Williams, Peter A

2006-02-28

Solution properties of tragacanthin (the water-soluble part of gum tragacanth) were studied by gel permeation chromatography (GPC) combined with multi-angle light scattering and viscometry at 25 degrees C. Photon correlation spectroscopy was used to determine the hydrodynamic radius. Ultrasonic degradation was applied to obtain biopolymer fractions of different molecular weights. The dependence of intrinsic viscosity [eta] and radius of gyration (s2)z(1/2) on weight average molecular mass M(w) for this biopolymer were found to be [eta] = 9.077 x 10(-5) M(w)(0.87) (dL g(-1)) and (s2)z(1/2) in the range of M(w) from 1.8 x 10(5) to 1.6 x 10(6). The conformational parameters of tragacanthin were calculated to be 1111 nm for molar mass per unit contour length (M(L)), 26 nm for persistence length (q) and 1.87 ratio of R(g)/R(h). It was found that the Smidsrød parameter B, the empirical stiffness parameter was 0.013, which is lower than that of several polysaccharides indicating the stiff backbone for tragacanthin. The rheological behavior of aqueous solutions of gum tragacanth and its insoluble and soluble fractions (bassorin and tragacanthin, respectively) were studied. For concentrations equal to 1%, at 25 degrees C and in the absence of salt, bassorin solution showed the highest viscosity and shear thinning behaviour. Power law and Williamson models were used to describe the rheological behaviour of bassorin and tragacanthin, respectively. Oscillatory shear experiments showed a gel like structure for the bassorin but for tragacanthin the oscillatory data were as would be expected for semi-dilute to concentrated solution of entangled, random coil polymers. NaCl changed the steady and oscillatory rheological properties of both fractions and in this way the final viscosity of bassorin was even less than tragacanthin. The calculated activation energy for bassorin and tragacanthin indicated a more rapid decrease in viscosity with temperature for tragacanthin. The plot of

Transport properties of dilute α -Fe (X ) solid solutions (X = C, N, O)

Science.gov (United States)

Schuler, Thomas; Nastar, Maylise

2016-06-01

We extend the self-consistent mean field (SCMF) method to the calculation of the Onsager matrix of Fe-based interstitial solid solutions. Both interstitial jumps and substitutional atom-vacancy exchanges are accounted for. A general procedure is introduced to split the Onsager matrix of a dilute solid solution into intrinsic cluster Onsager matrices, and extract from them flux-coupling ratios, mobilities, and association-dissociation rates for each cluster. The formalism is applied to vacancy-interstitial solute pairs in α -Fe (V X pairs, X = C, N, O), with ab initio based thermodynamic and kinetic parameters. Convergence of the cluster mobility contribution gives a controlled estimation of the cluster definition distance, taking into account both its thermodynamic and kinetic properties. Then, the flux-coupling behavior of each V X pair is discussed, and qualitative understanding is achieved from the comparison between various contributions to the Onsager matrix. Also, the effect of low-activation energy second-nearest-neighbor interstitial solute jumps around a vacancy on these results is addressed.

The Effect of Problem-Based Learning on Undergraduate Students' Learning about Solutions and Their Physical Properties and Scientific Processing Skills

Science.gov (United States)

Tosun, Cemal; Taskesenligil, Yavuz

2013-01-01

The aim of this study was to investigate the effect of Problem-Based Learning (PBL) on undergraduate students' learning about solutions and their physical properties, and on their scientific processing skills. The quasi experimental study was carried out through non-equivalent control and comparison groups pre-post test design. The data were…

Solution properties of solid and liquid potassium-indium alloys

International Nuclear Information System (INIS)

Takenaka, T.; Saboungi, M.L.

1987-01-01

It was recently shown by a combination of electrical resistivity, thermodynamic, and structural measurements that equiatomic alloys formed between K or Na and either Bi, Sb, Te, or Pb show pronounced deviations from ordinary metallic behavior and from ideal solution behavior, e.g., small values for the electrical conductivity and sharp peaks for the Darken excess stability function. Physical explanation of this behavior has been advanced on the basis of the formation of complex structural species similar to those reported for the corresponding solid alloys. The authors have chosen K-In alloys for several reasons. Phase diagram considerations coupled with small electronegativity differences between K and In would lead one to predict small deviations from ideal behavior, thus, this system would be suitable to test for oddities in alloy solution behavior in systems which deviate little from ideal behavior. Others have demonstrated that the position of the peak in the electrical resistivity changed in going from Li to Na and to K in the following sequence X/sub In/ ≅ 0.25, 0.40, and 0.50, respectively. The thermodynamic properties of these alloys would be expected to present similar trends

Synthesis, structural and semiconducting properties of Ba(Cu1/3 Sb2/3)O3-PbTiO3 solid solutions

Science.gov (United States)

Singh, Chandra Bhal; Kumar, Dinesh; Prashant, Verma, Narendra Kumar; Singh, Akhilesh Kumar

2018-05-01

We report the synthesis and properties of a new solid solution 0.05Ba(Cu1/3Sb2/3)O3-0.95PbTiO3 (BCS-PT) which shows the semiconducting properties. In this study, we have designed new perovskite-type (ABO3) solid solution of BCS-PT that have tunable optical band gap. BCS-PT compounds were prepared by conventional solid-state reaction method and their structural, micro-structural and optical properties were analyzed. The calcination temperature for BCS-PT solid solutions has been optimized to obtain a phase pure system. The Reitveld analysis of X-ray data show that all samples crystallize in tetragonal crystal structure with space group P4mm. X-ray investigation revealed that increase in calcination temperature led to increase of lattice parameter `a' while `c' parameter value lowered. The band gap of PbTiO3 is reduced from 3.2 eV to 2.8 eV with BCS doping and with increasing calcination temperature it further reduces to 2.56 eV. The reduced band gap indicated that the compounds are semiconducting and can be used for photovoltaic device applications.

Synthesis and properties of γ-Ga2O3-Al2O3 solid solutions

Science.gov (United States)

Afonasenko, T. N.; Leont'eva, N. N.; Talzi, V. P.; Smirnova, N. S.; Savel'eva, G. G.; Shilova, A. V.; Tsyrul'nikov, P. G.

2017-10-01

The textural and structural properties of mixed oxides Ga2O3-Al2O3, obtained via impregnating γ-Al2O3 with a solution of Ga(NO3)3 and subsequent heat treatment, are studied. According to the results from X-ray powder diffraction, gallium ions are incorporated into the structure of aluminum oxide to form a solid solution of spinel-type γ-Ga2O3-Al2O3 up to a Ga2O3 content of 50 wt % of the total weight of the sample, accompanied by a reduction in the specific surface area, volume, and average pore diameter. It is concluded that when the Ga2O3 content exceeds 50 wt %, the β-Ga2O3 phase is observed along with γ-Ga2O3-Al2O3 solid solution. 71Ga and 27Al NMR spectroscopy shows that gallium replaces aluminum atoms from the tetrahedral position to the octahedral coordination in the structure of γ-Ga2O3-Al2O3.

Composition, structure and electrical properties of alumina barrier layers grown in fluoride-containing oxalic acid solutions

Energy Technology Data Exchange (ETDEWEB)

Jagminas, A. [Institute of Chemistry, A. Gostauto 9, LT-01108 Vilnius (Lithuania)], E-mail: jagmin@ktl.mii.lt; Vrublevsky, I. [Department of Microelectricals, Belarusian State University of Informatics and Radioelectricals, 6 Brovka Street, Minsk 220013 (Belarus); Kuzmarskyte, J.; Jasulaitiene, V. [Institute of Chemistry, A. Gostauto 9, LT-01108 Vilnius (Lithuania)

2008-04-15

The composition, structure and electrical properties of alumina barrier layers grown by anodic oxidation in F{sup -}-containing (FC) and F{sup -}-free (FF) oxalic acid solutions were studied using the re-anodizing/dissolution technique, Fourier-transformed infrared and X-ray photoelectron spectroscopy. These results confirmed formation in FC anodizing solutions of films structurally different from ones grown in FF oxalic acid baths. It was found that the barrier layer of FC alumina films is composed of two layers differing in the dissolution rate. These differences are related to the formation in the FC electrolyte of a barrier layer composed of a more microporous outer part and a thin, non-porous and non-scalloped inner part consisting of aluminum oxide and aluminum fluoride.

Continuous properties of the data-to-solution map for a generalized μ-Camassa-Holm integrable equation

Science.gov (United States)

Yu, Shengqi

2018-05-01

This work studies a generalized μ-type integrable equation with both quadratic and cubic nonlinearities; the μ-Camassa-Holm and modified μ-Camassa-Holm equations are members of this family of equations. It has been shown that the Cauchy problem for this generalized μ-Camassa-Holm integrable equation is locally well-posed for initial data u0 ∈ Hs, s > 5/2. In this work, we further investigate the continuity properties to this equation. It is proved in this work that the data-to-solution map of the proposed equation is not uniformly continuous. It is also found that the solution map is Hölder continuous in the Hr-topology when 0 ≤ r < s with Hölder exponent α depending on both s and r.

Properties of filmogen solutions and films of hafnium compounds

International Nuclear Information System (INIS)

Sviridova, A.I.

1986-01-01

Study on hafnium hydrolizing compound solutions, used for hafnium oxide homogeneous layer formation, is conducted. In particular, electric conductivity, acidity and refractive index were investigated depending on the sal on ether concentration and the storage time. Oxyhafnium nitrate, hafnium chloride in ethanol, dichlorodiethoxyhafnium, hafnium oxychloride were used as initial compounds. Hydrolysis of hafnium compounds in solution occurs partially; further process occurs in the thin layer on the optical element surface; final decomposition is performed under heat treatment. It is ascertained, that alcoholic-aqueous solutions of inorganic salts can be filmogen only at definite acidity, density and viscosity (1.33-2.5 cp.). It is also ascertained that refractive index values and transmission spectral boundary of coatings, produced from alkoxy compound solutions and from chloride salt solutions, are practically the same. Transmittance boundary in ultraviolet region of spectrum of oxide films produced from nitrate and chloride solutions, varies with the heating temperature increase differently

Photophysical properties of betaxanthins: Vulgaxanthin I in aqueous and alcoholic solutions

Energy Technology Data Exchange (ETDEWEB)

Wendel, Monika [Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University in Poznan, Umultowska 85, Poznan 61-614 (Poland); Szot, Dominika; Starzak, Karolina; Tuwalska, Dorota [Faculty of Chemical Engineering and Technology, Institute C-1, Section of Analytical Chemistry, Cracow University of Technology, Warszawska 24, Cracow 31-155 (Poland); Gapinski, Jacek [Molecular Biophysics Department, Faculty of Physics, Adam Mickiewicz University in Poznan, Umultowska 85, Poznan 61-614 (Poland); Naskrecki, Ryszard [Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University in Poznan, Umultowska 85, Poznan 61-614 (Poland); Prukala, Dorota; Sikorski, Marek [Faculty of Chemistry, Adam Mickiewicz University in Poznan, Umultowska 89b, Poznan 61-614 (Poland); Wybraniec, Slawomir [Faculty of Chemical Engineering and Technology, Institute C-1, Section of Analytical Chemistry, Cracow University of Technology, Warszawska 24, Cracow 31-155 (Poland); Burdzinski, Gotard, E-mail: gotardb@amu.edu.pl [Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University in Poznan, Umultowska 85, Poznan 61-614 (Poland)

2015-11-15

Betaxanthins are yellow pigments present in Caryophyllales plants and some higher fungi. We characterize photophysical properties of vulgaxanthin I and extracts of Amanita muscaria L. Vulgaxanthin I photoexcitation at λ{sub exc}=476 nm leads to the S{sub 1} excited state with the S{sub 1}→S{sub n} absorption bands at ca. 390 and 920 nm in both aqueous and alcoholic solutions. The S{sub 1} state lifetimes (2.9 and 37 ps in water) imply that vulgaxanthin I exists in two stereoisomeric forms. An increase in the solvent viscosity extends the S{sub 1} lifetimes and fluorescence quantum yields, probably due to hindered internal rotations in the dye. Internal conversion is the major S{sub 1} state deactivation path, with fluorescence being a minor channel, and S{sub 1}→T{sub 1} intersystem crossing not observed. Betaxanthins extracted from A. muscaria L. have similar properties. Efficient dissipation of the absorbed light energy as heat supports the postulate of photoprotective role of betaxanthins in vivo. - Highlights: • Betaxanthin S{sub 1} state deactivation mechanism is mainly radiationless. • S{sub 1} state shows absorption band with maxima at about 390 nm and 920 nm. • Solvent viscosity affects S{sub 1} state lifetime and fluorescence quantum yield. • Addition of potassium iodide to solution enhances ISC in betaxanthin.

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.

Unraveling the Solution-State Supramolecular Structures of Donor-Acceptor Polymers and their Influence on Solid-State Morphology and Charge-Transport Properties.

Science.gov (United States)

Zheng, Yu-Qing; Yao, Ze-Fan; Lei, Ting; Dou, Jin-Hu; Yang, Chi-Yuan; Zou, Lin; Meng, Xiangyi; Ma, Wei; Wang, Jie-Yu; Pei, Jian

2017-11-01

Polymer self-assembly in solution prior to film fabrication makes solution-state structures critical for their solid-state packing and optoelectronic properties. However, unraveling the solution-state supramolecular structures is challenging, not to mention establishing a clear relationship between the solution-state structure and the charge-transport properties in field-effect transistors. Here, for the first time, it is revealed that the thin-film morphology of a conjugated polymer inherits the features of its solution-state supramolecular structures. A "solution-state supramolecular structure control" strategy is proposed to increase the electron mobility of a benzodifurandione-based oligo(p-phenylene vinylene) (BDOPV)-based polymer. It is shown that the solution-state structures of the BDOPV-based conjugated polymer can be tuned such that it forms a 1D rod-like structure in good solvent and a 2D lamellar structure in poor solvent. By tuning the solution-state structure, films with high crystallinity and good interdomain connectivity are obtained. The electron mobility significantly increases from the original value of 1.8 to 3.2 cm 2 V -1 s -1 . This work demonstrates that "solution-state supramolecular structure" control is critical for understanding and optimization of the thin-film morphology and charge-transport properties of conjugated polymers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Respiratory properties of blood and hemoglobin solutions from the piranha

DEFF Research Database (Denmark)

Wood, S.C.; Weber, Roy E.; Powers, D.

1979-01-01

1. Respiratory properties of piranha blood are distinguished from those of other fish primarily by the high CO2 buffering capacity (?HCO3/-?pH= 19.6mmol/l for oxygenated blood and 39.1 mmol/l for deoxygenated blood). 2. The concentration of nucleoside triphosphates (NTP) and the half-saturation t......) lowered the oxygen affinity of purified hemoglobin solutions, accounting for the size-dependent correlation ofP50 and NTP concentration in whole blood. 5. While similar in concentration in red cells, GTP is more potent than ATP as an allosteric modifier of hemoglobin function....

Unified scaling behavior of physical properties of clays in alcohol solutions.

Science.gov (United States)

Pujala, Ravi Kumar; Pawar, Nisha; Bohidar, H B

2011-12-15

This paper reports observation of universal scaling of physical properties of clay particles, Laponite (aspect ratio=30) (L) and Na Montmorillonite (MMT, aspect ratio=200), in aqueous alcohol solutions (methanol, ethanol and 1-propanol) with solvent polarity, defined through reaction field factor f(OH)(ɛ(0),n)=[(ɛ(0) - 1/ɛ(0) + 2) - (n(2) - 1/n(2) + 2)], at room temperature (20°C). Here, ɛ(0) and n are the static dielectric constant and refractive index of the solvent concerned. Physical properties (Z) such as zeta potential, effective aggregate size, viscosity and surface tension scaled with the relative solvent polarity as Z∼δf(α); δf=(f(w)(ɛ(0),n) - f(OH)(ɛ(0),n)), where f(w)(ɛ(0),n) is the reaction field factor for water, Z is the normalized physical property, and α is its characteristic scaling exponent. The value of this exponent was found to be invariant of aspect ratio of the clay but dependent on the solvent polarity only. Copyright © 2011 Elsevier Inc. All rights reserved.

Study of the confined solutions properties: case of gel formed during nuclear glass alteration

International Nuclear Information System (INIS)

Matar-Briman, I.

2012-01-01

In this study, we have investigated the thermodynamic properties, the structure and the dynamics of confined solutions in model gels and in a gel coming from glass alteration. The first step was to determine the structure and the dynamics of pure confined water in porous materials by using nuclear magnetic resonance and neutron scattering. Meso-porous silica was elaborated and grafted by sol-gel route to decrease the pore sizes from 2.7 to 2 nm and to modify pore surfaces to have Si-OH, Zr-OH and Al-OH. The second step involved determining the dynamics of water in leachate confined in the model gels and in the gel of altered glass by using neutron scattering. In the model gels and at a 10 -12 -10 -9 second timescale, two kinds of waters were highlighted: first, an interfacial water linked to the pore surfaces and second, a free water in the pore core. Their ratio depends on the pore size and pore surface composition. Whatever the pore surface, when the pore size decreases the free water ratio in the pore center also decreases. For pores smaller than 2.3 nm and pore surfaces with Zr-OH or Al-OH surfaces, water is strongly linked to the surface and few water molecules are mobile. This is due to the ability of alumina and zirconia to immobilize water molecules through chemical coordination bonds stronger than the physical bonds established between silica and water. The result also highlight that pore surface composition could be the predominant parameter affecting the fixed proton content. Moreover, the mobility of water confined in a leachate is not modified. The study of the water dynamics in a gel formed during alteration of glass constituted of SiO 2 , Al 2 O 3 and CaO, and having a porosity between 2 and 7 nm showed the same behavior as water confined in pores presenting an Al-OH surface. (author) [fr

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.

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

Thermodynamic properties of LiCl solutions in N-methylacetamide at 308.15-328.15 K

Science.gov (United States)

Manin, N. G.; Kolker, A. M.

2017-12-01

Enthalpies of dissolution of crystalline LiCl and enthalpies of dilution of LiCl solutions in N-methylacetamide (NMA) with electrolyte concentrations no greater than 0.32 m are measured on an isoperibolic calorimeter at 308.15, 318.15, and 328.5 K. Standard enthalpies of the dissolution of LiCl in NMA are calculated at different temperatures. The thermodynamic properties of the solution and its components are calculated and analyzed in the investigated range of concentrations and temperatures.

Sulfonated methyl esters of fatty acids in aqueous solutions: Interfacial and micellar properties.

Science.gov (United States)

Danov, Krassimir D; Stanimirova, Rumyana D; Kralchevsky, Peter A; Basheva, Elka S; Ivanova, Veronika I; Petkov, Jordan T

2015-11-01

The interest to sulfonated methyl esters of fatty acids (SME) has been growing during the last decade, because these surfactants are considered as an environmentally friendly and renewable alternative of the linear alkyl-benzene sulfonates (LAS). Here, we present a quantitative study on the properties of aqueous SME solutions, and especially on their surface tension isotherms, critical micelle concentration (CMC) and its dependence on the concentration of added NaCl. It is demonstrated that the CMC of an ionic surfactant determined by electrical conductivity is insensitive to the presence of a small nonionic admixture, so that the CMC values determined by conductivity represent the CMC of the pure surfactant. Using SME as an example, we have demonstrated the application of a new and powerful method for determining the physicochemical parameters of the pure ionic surfactant by theoretical data analysis ("computer purification") if the used surfactant sample contains nonionic admixtures, which are present as a rule. This method involves fits of the experimental data for surface tension and conductivity by a physicochemical model based on a system of mass-balance, chemical-equilibrium and electric-double-layer equations, which allows us to determine the adsorption and micellization parameters of C12-, C14-, C16- and C18-SME, as well the fraction of nonionic admixtures (if any). Having determined these parameters, we can further predict the interfacial and micellization properties of the surfactant solutions, such as surface tension, adsorption, degree of counterion binding, and surface electric potential at every surfactant, salt and co-surfactant concentrations. Copyright © 2015 Elsevier Inc. All rights reserved.

Size-dependent magnetic and structural properties of CoCrFeO4 nano-powder prepared by solution self-combustion

Science.gov (United States)

Sijo, A. K.; Dutta, Dimple P.

2018-04-01

The study reports the tuning of magnetic and structural properties of nano-sized CoCrFeO4 via post-annealing treatment. CoCrFeO4 nano-powder has been prepared by solution self-combustion method. The structural and magnetic properties have been studied over a range of annealing temperatures (300-900 °C). The formation of the phase pure CoCrFeO4 spinel has been confirmed from powder XRD analysis. The crystallite size is observed to increase with an increase in annealing temperature. On annealing, the value of magnetic parameters-remanence, coercivity and saturation magnetization have enhanced. All the samples exhibit irreversibility at low-temperature measurements.

Synthesis and spectral properties of preorganized BODIPYs in solutions and Langmuir-Schaefer films

Science.gov (United States)

Marfin, Yuriy S.; Usoltsev, Sergey D.; Kazak, Alexandr V.; Smirnova, Antonina I.; Rumyantsev, Evgeniy V.; Molchanov, Evgeniy E.; Kuznetsov, Vladimir V.; Chumakov, Alexey S.; Glukhovskoy, Evgeny G.

2017-12-01

In order to investigate the influence of molecular structure peculiarities of boron-dipyrrine dyes (BODIPYs) on their properties in solutions and supramolecular organization in Langmuir-Schaefer (LS) films, four new BODIPY dyes with various aliphatic, aromatic or mixed nature meso-subtituents were synthesized and investigated. Spectral characteristics (electronic absorption and fluorescence) of the synthesized compounds in organic solvents and LS-films were studied. Floating monolayers of the BODIPYs were formed from chloroform solutions placed onto water subphase in Langmuir-Blodgett through. Thin films were prepared using the Langmuir-Schaefer technique by the transfer of floating monolayers onto standard polished glass, ITO covered glass or pure silicon substrate. The variation of the dye structure we consider as a preorganization aiming to influence the structure of LS-films. The morphology and structure of the LS-films was examined by fluorescent microscopy, scanning electron microscopy, atomic force microscopy and small angle X-ray diffraction analysis. It was found that the introduced substituents have no substantial influence on the position of the absorption and fluorescence bands in dilute solutions. In contrast, the fluorescent characteristics of the LS-films significantly depend on the substituent nature. Therefore, this strategy could be used for the direct tuning of compounds fluorescent properties in LS-films. Concerning the LS-film surface characteristics it was proved that the films are homogeneous, without disruptions and only some widely-spaced microcrystals could be observed. With respect to the LS-film structure, the change of the substituents introduced to the BODIPY molecule did not influence the average given periodicity of layers (d = 0.3-0.4 nm). This value corresponds to a single-layer arrangement of BODIPY molecules located parallel to the substrate surface. Nevertheless, the diffraction peak intensities depended on the molecular

PRODUCTION, DIELECTRIC PROPERTY AND MICROWAVE ABSORPTION PROPERTY OF SiC(Fe SOLID SOLUTION POWDER BY SOL-GEL METHOD

Directory of Open Access Journals (Sweden)

XIAOLEI SU

2014-03-01

Full Text Available SiC(Fe solid solution powders were synthesized by sol–gel method under different reaction time, using methyltriethoxysilane as the silicon and carbon source and analytic ferric chloride as the dopant, respectively. The synthesized powders have been characterized by XRD, SEM and Raman spectra. Results show that the lattice constant decreases with increasing reaction time. The electric permittivities of SiC samples were determined in the frequency range of 8.2 ~ 12.4 GHz. Results show that the permittivity of SiC decreases with increasing reaction time. The SiC(Fe solid solution powder with reaction time of 4 h with 2 mm thickness exhibit the best microwave absorption property in X-band range (8.2 - 12.4 GHz. The microwave absorption mechanism has been discussed.

Decontamination solution development studies

International Nuclear Information System (INIS)

Allen, R.P.; Fetrow, L.K.; Kjarmo, H.E.; Pool, K.H.

1993-09-01

This study was conducted for the Westinghouse Hanford Company (WHC) by Pacific Northwest Laboratory (PNL) as part of the Hanford Grout Technology Program (HGTP). The objective of this study was to identify decontamination solutions capable of removing radioactive contaminants and grout from the Grout Treatment Facility (GTF) process equipment and to determine the impact of these solutions on equipment components and disposal options. The reference grout used in this study was prepared with simulated double-shell slurry feed (DSSF) and a dry blend consisting of 40 wt % limestone flour, 28 wt % blast furnace slag, 28 wt % fly ash, and 4 wt % type I/II Portland cement

Physico-chemical properties of aqueous drug solutions: From the basic thermodynamics to the advanced experimental and simulation results.

Science.gov (United States)

Bellich, Barbara; Gamini, Amelia; Brady, John W; Cesàro, Attilio

2018-04-05

The physical chemical properties of aqueous solutions of model compounds are illustrated in relation to hydration and solubility issues by using three perspectives: thermodynamic, spectroscopic and molecular dynamics simulations. The thermodynamic survey of the fundamental backgrounds of concentration dependence and experimental solubility results show some peculiar behavior of aqueous solutions with several types of similar solutes. Secondly, the use of a variety of experimental spectroscopic devices, operating under different experimental conditions of dimension and frequency, has produced a large amount of structural and dynamic data on aqueous solutions showing the richness of the information produced, depending on where and how the experiment is carried out. Finally, the use of molecular dynamics computational work is presented to highlight how the different types of solute functional groups and surface topologies organize adjacent water molecules differently. The highly valuable contribution of computer simulation studies in providing molecular explanations for experimental deductions, either of a thermodynamic or spectroscopic nature, is shown to have changed the current knowledge of many aqueous solution processes. While this paper is intended to provide a collective view on the latest literature results, still the presentation aims at a tutorial explanation of the potentials of the three methodologies in the field of aqueous solutions of pharmaceutical molecules. Copyright © 2018. Published by Elsevier B.V.

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.

Acid-base and coordination properties of Meso-substituted porphyrins in nonaqueous solutions

Science.gov (United States)

Pukhovskaya, S. G.; Nam, Dao Tkhe; Fien, Chan Ding; Domanina, E. N.; Ivanova, Yu. B.; Semeikin, A. S.

2017-09-01

Acid-base and coordination properties of alkyl and aryl meso-substituted porphyrins are studied spectrophotometrically in nonaqueous solutions. It is found that the nature of the substituent greatly affects the basicity of ligands for porphyrins characterized by a flat structure of macrocycle. The electronic effects of substituents have a much weaker influence on the kinetics of complexing. These effects could be due to the opposite orientation of some factors: an increase in the basicity and stability of the N-H bonds of porphyrin reaction centers. Dissociation constants p K b of the cationic forms of meso-substituted derivatives of porphyrin are measured. The values of p K b are in good agreement with classic concepts of the nature of substituents, particularly those indirectly included in the macrocycle through phenyl buffer rings.

Magnetic and electrical properties in BaNiS2-type solid solutions

International Nuclear Information System (INIS)

Irizawa, Akinori; Yoshimura, Kazuyoshi; Kosuge, Koji

2000-01-01

The magnetic and electrical properties are reported in the new solid solutions BaCo 1-x Cu x S 2 and BaNi 1-x Fe x S 2 . Both compounds show spin-glass-like behavior, although the type of spin frustrations is different with each other. BaCo 1-x Cu x S 2 shows a competition type spin-glass behavior with reentrant phenomenon from antiferromagnetic to spin-glass at low temperatures. BaNi 1-x Fe x S 2 shows a dilute type spin-glass behavior together with super-paramagnetic properties. The temperature variation of 57 Fe Moessbauer spectra in BaNi 0.8 Fe 0.2 S 2 is explicable in a framework of cluster-glass. (author)

Solution processing of polymer semiconductor: Insulator blends-Tailored optical properties through liquid-liquid phase separation control

KAUST Repository

Hellmann, Christoph; Treat, Neil D.; Scaccabarozzi, Alberto D.; Razzell Hollis, Joseph; Fleischli, Franziska D.; Bannock, James H.; de Mello, John; Michels, Jasper J.; Kim, Ji-Seon; Stingelin, Natalie

2014-01-01

© 2014 Wiley Periodicals, Inc. It has been demonstrated that the 0-0 absorption transition of poly(3-hexylthiophene) (P3HT) in blends with poly(ethylene oxide) (PEO) could be rationally tuned through the control of the liquid-liquid phase separation process during solution deposition. Pronounced J-like aggregation behavior, characteristic for systems of a low exciton band width, was found for blends where the most pronounced liquid-liquid phase separation occurred in solution, leading to domains of P3HT and PEO of high phase purity. Since liquid-liquid phase separation could be readily manipulated either by the solution temperature, solute concentration, or deposition temperature, to name a few parameters, our findings promise the design from the out-set of semiconductor:insulator architectures of pre-defined properties by manipulation of the interaction parameter between the solutes as well as the respective solute:solvent system using classical polymer science principles.

Solution processing of polymer semiconductor: Insulator blends-Tailored optical properties through liquid-liquid phase separation control

KAUST Repository

Hellmann, Christoph

2014-12-17

© 2014 Wiley Periodicals, Inc. It has been demonstrated that the 0-0 absorption transition of poly(3-hexylthiophene) (P3HT) in blends with poly(ethylene oxide) (PEO) could be rationally tuned through the control of the liquid-liquid phase separation process during solution deposition. Pronounced J-like aggregation behavior, characteristic for systems of a low exciton band width, was found for blends where the most pronounced liquid-liquid phase separation occurred in solution, leading to domains of P3HT and PEO of high phase purity. Since liquid-liquid phase separation could be readily manipulated either by the solution temperature, solute concentration, or deposition temperature, to name a few parameters, our findings promise the design from the out-set of semiconductor:insulator architectures of pre-defined properties by manipulation of the interaction parameter between the solutes as well as the respective solute:solvent system using classical polymer science principles.

Effect of Different Seed Solutions on the Morphology and Electrooptical Properties of ZnO Nanorods

Directory of Open Access Journals (Sweden)

M. Kashif

2012-01-01

Full Text Available The morphology and electrooptical properties of ZnO nanorods synthesized on monoethanolamine-based seed layer and KOH-based seed layer were compared. The seed solutions were prepared in monoethanolamine in 2-methoxyethanol and potassium hydroxide in methanol, respectively. Zinc acetate dihydrate was as a common precursor in both solutions. The nanorod-ZnOs were synthesized via the spin coating of two different seed solutions on silicon substrates followed by their hydrothermal growth. The scanning electron microscopy (SEM, X-ray diffraction (XRD, photoluminescence (PL, and Raman studies revealed that the ZnO nanorods obtained from monoethanolamine-based seed layer had fewer defects, better crystals, and better alignment than those realized via KOH-based seed layer. However, the current-voltage (I-V characteristics demonstrated better conductivity of the ZnO nanorods obtained via KOH-based seed layer. The current measured in forward bias was 4 mA and 40 μA for ZnO-nanorods grown on KOH-based seed layer and monoethanolamine-based with the turn on voltage of approximately 1.5 V and 2.5 V, respectively, showing the feasibility of using both structures in optoelectric devices.

Effect of heating rate on mechanical property, microstructure and texture evolution of Al–Mg–Si–Cu alloy during solution treatment

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiaofeng; Guo, Mingxing, E-mail: mingxingguo@skl.ustb.edu.cn; Cao, Lingyong; Luo, Jinru; Zhang, Jishan; Zhuang, Linzhong

2015-01-05

The effect of heating rate on the mechanical properties, microstructure and texture of Al–Mg–Si–Cu alloy during solution treatment was investigated through tensile testing, scanning electron microscope, scanning transmission electron microscope, metallographic observation and EBSD measurement. The experimental results reveal that there are great differences in the mechanical properties, microstructures and textures after the solution treatment with two different heating rates. Compared with the alloy sheet solution treated with slow heating rate, the alloy sheet solution treated with rapid heating rate possesses weak mechanical property anisotropy and higher average r value. The equiaxed grain is the main recrystallization microstructure for the case of rapid heating rate, while the elongated grain appears in the case of slow heating rate. The texture components are also quite different in the two cases, Cube{sub ND} orientation is the main texture component for the former case, while the latter one includes Cube, R, Goss, P and Brass orientations. The relationship between r value, texture components and microstructure has also been established in this paper.

Effect of heating rate on mechanical property, microstructure and texture evolution of Al–Mg–Si–Cu alloy during solution treatment

International Nuclear Information System (INIS)

Wang, Xiaofeng; Guo, Mingxing; Cao, Lingyong; Luo, Jinru; Zhang, Jishan; Zhuang, Linzhong

2015-01-01

The effect of heating rate on the mechanical properties, microstructure and texture of Al–Mg–Si–Cu alloy during solution treatment was investigated through tensile testing, scanning electron microscope, scanning transmission electron microscope, metallographic observation and EBSD measurement. The experimental results reveal that there are great differences in the mechanical properties, microstructures and textures after the solution treatment with two different heating rates. Compared with the alloy sheet solution treated with slow heating rate, the alloy sheet solution treated with rapid heating rate possesses weak mechanical property anisotropy and higher average r value. The equiaxed grain is the main recrystallization microstructure for the case of rapid heating rate, while the elongated grain appears in the case of slow heating rate. The texture components are also quite different in the two cases, Cube ND orientation is the main texture component for the former case, while the latter one includes Cube, R, Goss, P and Brass orientations. The relationship between r value, texture components and microstructure has also been established in this paper

Study of the formation of soluble complexes of sodium caseinate and xanthan in solution.

Science.gov (United States)

Bouhannache, Bouchra; HadjSadok, Abdelkader; Touabet, Abdelkrim

2017-09-01

The main objective of this work was to determinate the optimum conditions for the formation of soluble complexes between sodium caseinate and xanthan in solution at neutral pH, in the presence of the NaCl. The study of the influence of the concentrations of these three substances showed that salt was the most influent factor. It worsens the thermodynamic incompatibility of the two biopolymers in solution, when they are present at large amounts. However, it contributes to soluble complexes formation, when sodium caseinate concentration is below 5.5%. In this case, gels with enhanced rheological properties were obtained. Infrared spectroscopy confirmed that the complexes formation within these gels involves hydrophobic interactions. On the other hand, dynamic light scattering revealed that dilution cause their dissociation. These soluble complexes are promising ingredients to ensure new texturing properties.

Studying the Super-cooled Solid Solution Breakdown of V-1341 Aluminum Alloy

Directory of Open Access Journals (Sweden)

Yu. A. Puchkov

2017-01-01

Full Text Available Deformable alloys of the Al-Mg-Si system are widely used in aviation industry, rocket engineering, shipbuilding, as well as on railway and highway transport. These alloys are characterized by high stamping ability, weld-ability, and machinability with a comparatively high strength and corrosion resistance in a heat-strengthened state. A promising alloy of the Al-Mg-Si system with increased structural strength and manufacturability is on par with foreign analogues in properties is the V-1341 alloy [1, 2].The properties of heat-treatable aluminum alloys strongly depend on the cooling rate of the product during quenching [3-12], which determines the structure and level of residual stresses. Decrease in structural strength, tendency to pitting and inter-crystalline corrosion with slow cooling from the quenching temperature is caused by formation of coarse unequiaxed precipitate, precipitates-free zones, and also by decreasing proportion of inclusions of the strengthening phase [3-12].Thus, the relevant task is to study the effect of isothermal quenching modes on the structure of deformable V-1341 aluminum alloy thermally hardened.The paper studies the impact of isothermal time in quenching on the composition and morphology of breakdown products of the V-1341 alloy solid solution. It is shown that at isothermal time under the solid solution breakdown, at first on the dispersoid surface and then in the solid solution are formed and grow large needle-like crystals of the β'-phase which are structural concentrators of stresses. An increasing isothermal time leads to decreasing solid solution super-saturation by doping elements and vacancies. This leads to a decrease in the fraction of the coherent finely dispersed hardening β '' phase, and also to an increase in the width of the precipitates-free zone.

Microstructural and microchemical studies of phase stability in V-O solid solution

Energy Technology Data Exchange (ETDEWEB)

Ghosh, Chanchal, E-mail: chanchal@igcar.gov.in [Metallurgy & Materials Group, Indira Gandhi Centre for Atomic Research, HBNI, Kalpakkam 603102, Tamil Nadu (India); Singh, Akash [Metallurgy & Materials Group, Indira Gandhi Centre for Atomic Research, HBNI, Kalpakkam 603102, Tamil Nadu (India); Basu, Joysurya [Metallurgy & Materials Group, Indira Gandhi Centre for Atomic Research, HBNI, Kalpakkam 603102, Tamil Nadu (India); Department of Metallurgical Engineering, Indian Institute of Technology (BHU), Varanasi 221005, Uttar Pradesh (India); Ramachandran, Divakar; Mohandas, E [Metallurgy & Materials Group, Indira Gandhi Centre for Atomic Research, HBNI, Kalpakkam 603102, Tamil Nadu (India)

2017-02-15

Over the last couple of decades vanadium and V-based alloys have received significant attention as a potential structural material for fusion power applications because of their favourable mechanical properties under irradiation and at elevated temperatures. They are also considered as the advanced options of storage materials for hydrogen and its isotopes. However, the higher affinity of V for O, C and N poses critical challenges in its engineering applications since they lead to degradation of mechanical properties. They can further interact with the matrix to produce metallic oxy-carbo-nitride precipitates. To a certain limit, these precipitates are beneficial and can be exploited to enhance the mechanical behaviour of the alloy through suitable microstructural design. However, this requires a prior knowledge of the interaction between the alloy and the impurity solutes. In the present work vanadium specific experiments have been designed and carried out to bring out the V-interstitial solute interaction by charging oxygen in the near surface region of vanadium. Microstructural and microchemical behaviour of the V-O solid solution has been studied through HRTEM (high resolution transmission electron microscopy) and HAADF (high angle annular dark field) coupled with EELS. Quantitative electron microscopy has been carried out to study structural modification of the alloy in atomic level caused by O charging. - Highlights: •Controlled experiments were carried out in pulsed laser ablation set-up to promote V-O interaction. • As a consequence of O dissolution, V transformed into a bct structure which is otherwise a bcc structure. •In V-O solid solution, dissolved O in the V matrix introduces significant amount of lattice strain. • Present work can be extended for introducing interstitial O in other pure transition metals and their alloys.

An analytical longitudinal dielectric function of primitive electrolyte solutions and its application in predicting thermodynamic properties

International Nuclear Information System (INIS)

Xiao, Tiejun

2015-01-01

In this paper, the longitudinal dielectric function ϵ_l(k) of primitive electrolyte solutions is discussed. Starting from a modified mean spherical approximation, an analytical dielectric function in terms of two parameters is established. These two parameters can be related to the first two decay parameters k_1_,_2 of the dielectric response modes of the bulk system, and can be determined using constraints of k_1_,_2 from statistical theories. Furthermore, a combination of this dielectric function and the molecular Debye-Hückel theory[J. Chem. Phys. 135(2011)104104] leads to a self-consistent mean filed description of electrolyte solutions. Our theory reveals a relationship between the microscopic structure parameters of electrolyte solutions and the macroscopic thermodynamic properties, which is applied to concentrated electrolyte solutions.

Effects of addition glycerol co-product of biodiesel in the thermophysical properties of water-glycerol solution applied as secondary coolant

Energy Technology Data Exchange (ETDEWEB)

Medeiros, Pedro Samuel Gomes; Barbosa, Cleiton Rubens Formiga; Fontes, Francisco de Assis Oliveira [Federal University of Rio Grande do Norte, Natal, RN (Brazil). Energy Laboratory. Thermal Systems Studies Group], e-mail: cleiton@ufrnet.br

2010-07-01

This paper evaluates the effects of glycerol concentration on thermophysical properties of water-glycerol solution applied as a secondary coolant in refrigeration systems by expansion-indirect. The processing of triglycerides for biodiesel production generates glycerol as co-product and there are concerns of environmental and economic order on the surplus of glycerol. The addition of glycerol in water alters the colligative and thermophysical properties (melting point, mass, specific heat, thermal conductivity and dynamic viscosity). There are studies that prove the feasibility of using glycerol as an additive and this paper has the goal to verify the changes on properties compared with pure water. This comparison was made from data obtained by the software simulation and they analyzed using graphs and tables. It was shown that glycerol increases the density and dynamic viscosity, and reduces the specific heat and thermal conductivity. This behavior of water-glycerol solution is proportional to the mass concentration of glycerol and it is justified because the glycerol has low values of specific heat, thermal conductivity and high viscosity when compared with water. Despite the losses in the thermophysical properties, glycerol shows its potential application, because of the cryoscopic effect and it is a non-toxic substance at low cost. (author)

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

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.

Effect of gamma radiation on glucose and sodium chloride solutions for injection

International Nuclear Information System (INIS)

Lakoza, G.N.; Grigor'eva, O.L.; Mart'yanova, B.M.; Vorob'eva, E.N.; Kuznetsova, R.M.

1976-01-01

Irradiation of 40% glucose solution with 0.5-4.0 Mrads di not affect the detoxicating properties of glucose or its ability to raise blood sugar levels. Such doses had no effect on the toxicological properties of 40% glucose solution and on 0.9% sodium chloride solution. The biological and physicochemical properties of 40% solution and 0.9% sodium chloride solutions irradiated with sterilizing doses showed no significant alterations during storage for one and three years, respectively. It is concluded that the solutions studied may be sterilized by radiation. (auth.)

Local Properties of Solutions to Non-Autonomous Parabolic PDEs with State-Dependent Delays

Czech Academy of Sciences Publication Activity Database

Rezunenko, Oleksandr

2012-01-01

Roč. 2, č. 2 (2012), s. 56-71 ISSN 2158-611X R&D Projects: GA ČR(CZ) GAP103/12/2431 Institutional support: RVO:67985556 Keywords : partial differential equations * state-dependent delay * invariance principle Subject RIV: BC - Control Systems Theory http://library.utia.cas.cz/separaty/2012/AS/rezunenko- local properties of solutions to non-autonomous parabolic PDEs with state-dependent delay s.pdf

Structural analysis and magnetic properties of solid solutions of Co–Cr system obtained by mechanical alloying

International Nuclear Information System (INIS)

Betancourt-Cantera, J.A.; Sánchez-De Jesús, F.; Bolarín-Miró, A.M.; Betancourt, I.; Torres-Villaseñor, G.

2014-01-01

In this paper, a systematic study on the structural and magnetic properties of Co 100−x Cr x alloys (0 1−x Cr x (0 2 /kg) for the Co 90 Cr 10 , which decreases with the increasing of the Cr content up to x=80, as a consequence of the dilution effect of the magnetic moment which is caused by the Cr content and by the competition between ferromagnetic and antiferromagnetic exchange interactions. The coercivity increases up to 34 kA/m (435 Oe) for Co 40 Cr 60 . For Cr rich compositions, it is observed an important decrease reaching 21 kA/m (272 Oe) for Co 10 Cr 90, it is related to the grain size and the structural change. Besides, the magnetic anisotropy constant was determined for each composition. Magnetic thermogravimetric analysis allowed to obtain Curie temperatures corresponding to the formation of hcp-Co(Cr) and fcc-Co(Cr) solid solutions. - Highlights: • Mechanical alloying (MA) induces the formation of solid solutions of Co–Cr system in non-equilibrium. • We report the crystal structure and the magnetic behavior of Co–Cr alloys produced by MA. • MA improves the magnetic properties of Co–Cr system

Homogeneous solutions of stationary Navier-Stokes equations with isolated singularities on the unit sphere. II. Classification of axisymmetric no-swirl solutions

Science.gov (United States)

Li, Li; Li, YanYan; Yan, Xukai

2018-05-01

We classify all (- 1)-homogeneous axisymmetric no-swirl solutions of incompressible stationary Navier-Stokes equations in three dimension which are smooth on the unit sphere minus the south and north poles, parameterizing them as a four dimensional surface with boundary in appropriate function spaces. Then we establish smoothness properties of the solution surface in the four parameters. The smoothness properties will be used in a subsequent paper where we study the existence of (- 1)-homogeneous axisymmetric solutions with non-zero swirl on S2 ∖ { S , N }, emanating from the four dimensional solution surface.

Synthesis and Rheological Properties of an Associative Star Polymer in Aqueous Solutions

DEFF Research Database (Denmark)

Hietala, Sami; Mononen, Pekka; Strandman, Satu

2007-01-01

synthesised by atom transfer radical. polymerization (ATRP) was found to fonn hydrogels at room temperature at polymer concentrations. Cp, over 22 gIL due to the interpolymer drophobic association of the PS blocks. Increasing Cp leads to stronger elastic networks at room temperature that show a gel......Rheological properties of aqueous solutions and hydrogels fonned by an amphiphiIic star block copolymer poly(acrylic acid)-blockpolystyrene (PAAS4-b-PS6)4. were investigated as a function of the polymer concentration (Cp), temperature, and added saIt concentration. The water-soluble polymer......-to-solution transition with increasing temperature. Increase of ionic strength decreases the moduli compared with the pure hydrogel but did not affect the gel-sol transition temperature significantly. Small-angle X-ray experiments showed two distinct scattering correlation peaks for samples above the gelling Cp, which...

Thermoelectric properties of Bi2Te3 base solid solutions in the Bi2Te3-InS system

International Nuclear Information System (INIS)

Safarov, M.G.; Rustamov, P.G.; Alidzhanov, M.A.

1979-01-01

The rich Bi 2 Te 3 part ot the Bi 2 Te 3 -InS constitutional diagram has been studied with a view to produce new Bi 2 Te 3 -based solid solutions and to establish the maximum solubility of InS in Bi 2 Te 3 . The methods of differential-thermal, X-ray phase and microstructural analysis have been used. The alloys microhardness, density and thermal electric properties have been measured. A large region of Bi 2 Te 3 -based restricted solid solutions has been detected; it reaches 14.0 mol.% InS at room temperature. Studied have been the thermoelectromotive forces, electric and thermal conductivity of the alloys, containing up to 5 mol.% InS in the 300-700 K temperature range

Exposure to buffer solution alters tendon hydration and mechanics.

Science.gov (United States)

Safa, Babak N; Meadows, Kyle D; Szczesny, Spencer E; Elliott, Dawn M

2017-08-16

A buffer solution is often used to maintain tissue hydration during mechanical testing. The most commonly used buffer solution is a physiological concentration of phosphate buffered saline (PBS); however, PBS increases the tissue's water content and decreases its tensile stiffness. In addition, solutes from the buffer can diffuse into the tissue and interact with its structure and mechanics. These bathing solution effects can confound the outcome and interpretation of mechanical tests. Potential bathing solution artifacts, including solute diffusion, and their effect on mechanical properties, are not well understood. The objective of this study was to measure the effects of long-term exposure of rat tail tendon fascicles to several concentrations (0.9-25%) of NaCl, sucrose, polyethylene glycol (PEG), and SPEG (NaCl+PEG) solutions on water content, solute diffusion, and mechanical properties. We found that with an increase in solute concentration the apparent water content decreased for all solution types. Solutes diffused into the tissue for NaCl and sucrose, however, no solute diffusion was observed for PEG or SPEG. The mechanical properties changed for both NaCl solutions, in particular after long-term (8h) incubation the modulus and equilibrium stress decreased compared to short-term (15min) for 25% NaCl, and the cross sectional area increased for 0.9% NaCl. However, the mechanical properties were unchanged for both PEG and SPEG except for minor alterations in stress relaxation parameters. This study shows that NaCl and sucrose buffer solutions are not suitable for long-term mechanical tests. We therefore propose using PEG or SPEG as alternative buffer solutions that after long-term incubation can maintain tissue hydration without solute diffusion and produce a consistent mechanical response. Copyright © 2017 Elsevier Ltd. All rights reserved.

Changes in mechanical properties and morphology of elastomer coatings after immersion in salt solutions

Science.gov (United States)

Terán Arce, Fernando; Avci, Recep; Beech, Iwona; Cooksey, Keith; Wigglesworth-Cooksey, Barbara

2004-03-01

RTV11 (^TM GE Silicones) and Intersleek (^TM International Paints) are two elastomers of considerable significance to the navy and maritime industry for their application as fouling release coatings. Both materials are composed of polymeric matrices with embedded filler particles, which provide increased strength and durability to the elastomer. Using Atomic force microscopy (AFM), surface and bulk analysis techniques, we have found surface regions with microelastic properties, which correlate with the locations of filler particles inside the coatings. These particles are able to undergo elastic displacements of hundreds of nm inside the polymeric matrix during compression by the AFM tip. While elastic properties of Intersleek remain largely unchanged after immersion in salt solutions, roughening, embrittlement and stiffening occurs in RTV11 coatings depending on the amount of curing agent and humidity used during preparation and curing, respectively. Interestingly, such transformations are absent after immersion in pure water. In particle free regions, elastic moduli of RTV11 take values of 2 - 3 MPa before immersion in salt solutions. After immersion, those values increase 5 - 10 times.

Effect of temperature and ionic strength on volumetric and acoustic properties of solutions of urea alkyl derivatives in aqueous NaCl

International Nuclear Information System (INIS)

Krakowiak, Joanna; Wawer, Jarosław

2015-01-01

Highlights: • Urea and its alkyl derivatives in aqueous NaCl solutions were studied. • The density and the speed of sound were measured for presented systems. • The strongest impact of NaCl on obtained quantities is noticed for apparent molar compression. • Bigger hydrophobic character of the solute results in bigger changes of calculated quantities with concentration. • The geometry of the solute is a crucial condition for hydrophobic hydration to happen. - Abstract: The present work was undertaken to study volumetric and acoustic properties for diluted solutions of tetramethylurea in pure water and for urea, n-propylurea, n-butylurea and tetramethylurea in 0.5 or 1 mol · dm −3 aqueous solutions of sodium chloride. This paper presents measured values of densities and sound velocities at T = (288.15, 298.15 and 308.15) K. From these data the apparent molar volumes, V Φ , adiabatic compressibilities, κ S , and apparent molar adiabatic compressions, K S,Φ , were obtained. The values of apparent molar volumes for infinite dilution and limited apparent adiabatic compressions were calculated from extrapolation of the concentration dependence. Further, the corresponding transfer data as well as hydration number of urea and its derivatives in the studied systems were estimated. The obtained parameters are discussed in terms of various solute-solvent and solute-cosolute interactions

Preparation, Structural and Dielectric Properties of Solution Grown Polyvinyl Alcohol(PVA) Film

Science.gov (United States)

Nangia, Rakhi; Shukla, Neeraj K.; Sharma, Ambika

2017-08-01

Flexible dielectrics with high permittivity have been investigated extensively due to their applications in electronic industry. In this work, structural and electrical characteristics of polymer based film have been analysed. Poly vinyl alcohol (PVA) film was prepared by solution casting method. X-ray diffraction (XRD) characterization technique is used to investigate the structural properties. The semi-crystalline nature has been determined by the analysis of the obtained XRD pattern. Electrical properties of the synthesized film have been analysed from the C-V and I-V curves obtained at various frequencies and temperatures. Low conductivity values confirm the insulating behaviour of the film. However, it is found that conductivity increases with temperature. Also, the dielectric permittivity is found to be higher at lower frequencies and higher temperatures, that proves PVA to be an excellent dielectric material which can be used in interface electronics. Dielectric behaviour of the film has been explained based on dipole orientations to slow and fast varying electric field. However further engineering can be done to modulate the structural, electrical properties of the film.

Four Thermochromic o-Hydroxy Schiff Bases of α-Aminodiphenylmethane: Solution and Solid State Study

Directory of Open Access Journals (Sweden)

Marija Zbačnik

2017-01-01

Full Text Available More than a hundred years after the first studies of the photo- and thermochromism of o-hydroxy Schiff bases (imines, it is still an intriguing topic that fascinates several research groups around the world. The reasons for such behavior are still under investigation, and this work is a part of it. We report the solution-based and mechanochemical synthesis of four o-hydroxy imines derived from α-aminodiphenylmethane. The thermochromic properties were studied for the single crystal and polycrystalline samples of the imines. The supramolecular impact on the keto-enol tautomerism in the solid state was studied using SCXRD and NMR, while NMR spectroscopy was used for the solution state. All four imines are thermochromic, although the color changes of the single crystals are not as strong as of the polycrystalline samples. One of the imines shows negative thermochromism, and that one is in keto-amine tautomeric form, both in the solid state as in solution.

Structural and optical properties of Co-doped ZnO nanocrystallites prepared by a one-step solution route

International Nuclear Information System (INIS)

Li Ping; Wang Sha; Li Jibiao; Wei Yu

2012-01-01

Zinc oxide (ZnO) nanocrystallites with different Co-doping levels were successfully synthesized by a simple one-step solution route at low temperature (95 deg. C) in this study. The structure and morphology of the samples thus obtained were characterized by XRD, EDS, XPS and FESEM. Results show that cobalt ions, in the oxidation state of Co 2+ , replace Zn 2+ ions in the ZnO lattice without changing its wurtzite structure. The dopant content varies from 0.59% to 5.39%, based on Co-doping levels. The pure ZnO particles exhibit well-defined 3D flower-like morphology with an average size of 550 nm, while the particles obtained after Co-doping are mostly cauliflower-like nanoclusters with an average size of 120 nm. Both the flower-like pure ZnO and the cauliflower-like Co:ZnO nanoclusters are composed of densely arrayed nanorods. The optical properties of the ZnO nanocrystallites following Co-doping were also investigated by UV-Visible absorption and Photoluminescence spectra. Our results indicate that Co-doping can change the energy-band structure and effectively adjust the luminescence properties of ZnO nanocrystallites. - Highlights: → Co-doped ZnO nanocrystallites were synthesized via a simple one-step solution route. → Co 2+ ions incorporated into the ZnO lattice without changing its wurtzite structure. → Co-doping changed the energy band structure of ZnO. → Co-doping effectively adjusted the luminescence properties of ZnO nanocrystallites.

Structural and optical properties of Co-doped ZnO nanocrystallites prepared by a one-step solution route

Energy Technology Data Exchange (ETDEWEB)

Li Ping, E-mail: lipingchina@yahoo.com.cn [Provincial Key Laboratory of Inorganic Nanomaterials, School of Chemistry and Materials Science, Hebei Normal University, 113 Yuhua Road, Shijiazhuang 050016, Hebei (China); Wang Sha; Li Jibiao; Wei Yu [Provincial Key Laboratory of Inorganic Nanomaterials, School of Chemistry and Materials Science, Hebei Normal University, 113 Yuhua Road, Shijiazhuang 050016, Hebei (China)

2012-01-15

Zinc oxide (ZnO) nanocrystallites with different Co-doping levels were successfully synthesized by a simple one-step solution route at low temperature (95 deg. C) in this study. The structure and morphology of the samples thus obtained were characterized by XRD, EDS, XPS and FESEM. Results show that cobalt ions, in the oxidation state of Co{sup 2+}, replace Zn{sup 2+} ions in the ZnO lattice without changing its wurtzite structure. The dopant content varies from 0.59% to 5.39%, based on Co-doping levels. The pure ZnO particles exhibit well-defined 3D flower-like morphology with an average size of 550 nm, while the particles obtained after Co-doping are mostly cauliflower-like nanoclusters with an average size of 120 nm. Both the flower-like pure ZnO and the cauliflower-like Co:ZnO nanoclusters are composed of densely arrayed nanorods. The optical properties of the ZnO nanocrystallites following Co-doping were also investigated by UV-Visible absorption and Photoluminescence spectra. Our results indicate that Co-doping can change the energy-band structure and effectively adjust the luminescence properties of ZnO nanocrystallites. - Highlights: > Co-doped ZnO nanocrystallites were synthesized via a simple one-step solution route. > Co{sup 2+} ions incorporated into the ZnO lattice without changing its wurtzite structure. > Co-doping changed the energy band structure of ZnO. > Co-doping effectively adjusted the luminescence properties of ZnO nanocrystallites.

The influence of surface modification, coating agents and pH value of aqueous solutions on physical properties of magnetite nanoparticles investigated by ESR method

Energy Technology Data Exchange (ETDEWEB)

Dobosz, Bernadeta, E-mail: benia@amu.edu.pl [Medical Physics Division, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland); Krzyminiewski, Ryszard [Medical Physics Division, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland); Kurczewska, Joanna; Schroeder, Grzegorz [Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89B, 61-614 Poznań (Poland)

2017-05-01

The article presents the results of electron spin resonance (ESR) studies for aqueous solutions of functionalized superparamagnetic iron(II,III) oxide nanoparticles. The samples studied differed in type of organic ligands at the magnetite surface, type of coating agent and pH value of aqueous solutions. The ESR spectra of the samples were obtained at room temperature and at 230 K. The field cooling (FC) experiment was performed for selected samples, and the effective anisotropy field (H{sub K2}) and the first order magnetocrystalline anisotropy constant (K{sub 1}) was calculated. The process of the nanoparticles diffusion in different environments (human blood, human serum) forced by an inhomogeneous magnetic field was monitored and their interactions with different solvents have been discussed. It has been shown that ESR method is useful to observe the impact of organic ligands at the magnetite surface, type of coating agent and pH value of aqueous solutions on the properties of iron(II,III) oxide nanoparticles. - Highlights: • The influence of different organic ligands, coatings and pH values of aqueous solutions on the physical properties of the magnetite nanoparticles studied by ESR method. • Nanoparticles diffusion forced by inhomogeneous magnetic field monitored by ESR and explained. • A narrow line separated in ESR spectra by CREM. • The influence of different coatings and pH values of aqueous solutions on ESR spectra of TEMPO attached to the magnetite core.

Properties of solvated electrons, alkali anions and other species in metal solutions and kinetics of cation and electron exchange reactions. Final report

International Nuclear Information System (INIS)

Dye, J.L.

1979-01-01

The properties of solutions of alkali metals in amine solvents were studied by optical, ETR, NMR and electrochemical methods. Complexation of the alkali cations by crown ethers and cryptands permitted the preparation of concentrated solutions of alkali metals in amine and ether solvents. Extensive alkali metal NMR studies of the exchange of M + with crown-ethers and cryptands and of the alkali metal anion, M - , were made. The first crystalline salt of an alkali metal anion, Na + Cryptand [2.2.2]Na - was synthesized and characterized and led to the preparation of other alkali metal anion salts. This research provided the foundation for continuing studies of crystalline alkalide salts

Estimation of soil-soil solution distribution coefficient of radiostrontium using soil properties.

Science.gov (United States)

Ishikawa, Nao K; Uchida, Shigeo; Tagami, Keiko

2009-02-01

We propose a new approach for estimation of soil-soil solution distribution coefficient (K(d)) of radiostrontium using some selected soil properties. We used 142 Japanese agricultural soil samples (35 Andosol, 25 Cambisol, 77 Fluvisol, and 5 others) for which Sr-K(d) values had been determined by a batch sorption test and listed in our database. Spearman's rank correlation test was carried out to investigate correlations between Sr-K(d) values and soil properties. Electrical conductivity and water soluble Ca had good correlations with Sr-K(d) values for all soil groups. Then, we found a high correlation between the ratio of exchangeable Ca to Ca concentration in water soluble fraction and Sr-K(d) values with correlation coefficient R=0.72. This pointed us toward a relatively easy way to estimate Sr-K(d) values.

Orientational structure formation of silk fibroin with anisotropic properties in solutions

International Nuclear Information System (INIS)

Kholmuminov, A.A.

2008-06-01

on the boundary 'reservoir - withdrawing capillary' of gland, initiating the transition of α-spiral in β-structures as well as phase separation of fibroin and sericin in stream were discovered; the phase diagram of liquidus for secret in the framework of polymers orientation crystallization conception were suggested; the mechanism of fibroin orientational crystallization under the longitudinal flow of solutions and gels was conformed experimentally; the scientific principles of oriented-crystallized fibrillar biopolymer materials receipt were established on the base of fibroin model solutions with properties of anisotropy of moisture absorption, swelling, desorption, thermo- and biodegradation; the approach of jointly using polarization-optical and hydrodynamic methods to the investigation of fibrillar biopolymers structure formation and phase transformations in solution was developed. Practical value - the elucidated physical regularities of fibroin solution allow to formulate a new idea on fibrillar biopolymer solutions formation and to get on their late model systems for practical use; the established scientific principles of orientational structure-formation and phase transformation of fibroin will be the base for development of original methods of anisotropic biopolymer materials from solutions of the polarization-optical and developed hydrodynamic methods can be used for the investigation of structure and phase transformations of wide range of fibrillar biopolymer samples. Sphere of usage: physics of anisotropic polymer systems, macromolecular compounds solutions, gels, crystals, biopolymers materials science, optical polarization and hydrodynamics. (author)

Thermodynamic modeling of iodine and selenium retention in solutions with high salinity

International Nuclear Information System (INIS)

Hagemann, Sven; Moog, Helge C.; Herbert, Horst-Juergen; Erich, Agathe

2012-04-01

The report on iodine and selenium retention in saline solutions includes the following chapters: (1) Introduction and scope of the work. (2) Actual status of knowledge. (3) Experimental and numerical models. (4) Thermodynamic properties of selenite and hydrogen selenite in solutions of oceanic salts. (5) Thermodynamic properties of selenate in solutions of oceanic salts. (6) Thermodynamic properties of iodide in solutions of oceanic salts. (7) Experimental studies on the retention of iodine and selenium in selected sorbents. (8) Summary and conclusions.

Analytical solution for the electrical properties of a radio-frequency quadrupole (RFQ) with simple vanes

International Nuclear Information System (INIS)

Lancaster, H.

1982-01-01

Although the SUPERFISH program is used for calculating the design parameters of an RFQ structure with complex vanes, an analytical solution for electrical properties of an RFQ with simple vanes provides insight into the parametric behavior of these more complicated resonators. The fields in an inclined plane wave guide with proper boundary conditions match those in one quadrant of an RFQ. The principle of duality is used to exploit the solutions to a radial transmission line in solving the field equations. Calculated are the frequency equation, frequency sensitivity factors, electric field, magnetic field, stored energy (U), power dissipation, and quality factor

Properties of solutions in semi-hyperbolic patches for unsteady transonic small disturbance equations

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Ilija Jegdic

2015-09-01

Full Text Available We consider a two-dimensional Riemann problem for the unsteady transonic small disturbance equation resulting in diverging rarefaction waves. We write the problem in self-similar coordinates and we obtain a mixed type (hyperbolic-elliptic system. Resolving the one-dimensional discontinuities in the far field, where the system is hyperbolic, and using characteristics, we formulate the problem in a semi-hyperbolic patch that is between the hyperbolic and the elliptic regions. A semi-hyperbolic patch is known as a region where one family out of two nonlinear families of characteristics starts on a sonic curve and ends on a transonic shock. We obtain existence of a smooth local solution in this semi-hyperbolic patch and we prove various properties of global smooth solutions based on a characteristic decomposition using directional derivatives.

The Modification of Sodium Polyacrylate Water Solution Cooling Properties by AL2O3

Directory of Open Access Journals (Sweden)

Wojciech Gęstwa

2010-01-01

Based on cooling curves, it can be concluded that for the water solution of sodium polyacrylate with AL2O3 nanoparticles in comparison to water and 10% polymer water solution lower cooling speed is obtained. The cooling medium containing nanoparticles provides lower cooling speed in the smallest surface austenite occurance (500–600 C in the charts of the CTP for most nonalloy structural steels and low-alloy steels. However lower cooling temperature at the beginning of martensitic transformation causes the formation of smaller internal stresses, leading to smaller dimensional changes and hardening deformation. For the quenching media the wetting angle was appointed by the drop-shape method. These studies showed the best wettability of polymer water solution (sodium polyacrylate with the addition of AL2O3 nanoparticles, whose wetting angle was about 65 degrees. Obtaining the smallest wetting angle for the medium containing nanoparticles suggests that the heat transfer to the cooling medium is larger. This allows slower cooling at the same time ensuring its homogeneity. The obtained values of wetting angle confirm the conclusions drawn on the basis of cooling curves and allowus to conclude that in the case of the heat transfer rate it will have a lower value than for water and 10% polymer water solution. In the research on hardened carburized steel samples C10 and 16MnCr5 surface hardness, impact strength and changes in the size of cracks in Navy C-ring sample are examined. On this basis of the obtained results it can be concluded that polymer water solution with nanoparticles allows to obtain a better impact strength at comparable hardness on the surface. Research on the dimensional changes on the basis of the sample of Navy C-ring also shows small dimensional changes for samples carburized and hardened in 10% polymer water solution with the addition of nanoparticles AL2O3. Smaller dimensional changes were obtained for samples of steel 16MnCr5 thanfar C10. The

Stability studies of oxytetracycline in methanol solution

Science.gov (United States)

Wang, Wei; Wu, Nan; Yang, Jinghui; Zeng, Ming; Xu, Chenshan; Li, Lun; Zhang, Meng; Li, Liting

2018-02-01

As one kind of typical tetracycline antibiotics, antibiotic residues of oxytetracycline have been frequently detected in many environmental media. In this study, the stability of oxytetracycline in methanol solution was investigated by high-performance liquid chromatography combined with UV-vis (HPLC-UV). The results show that the stability of oxytetracycline in methanol solution is highly related to its initial concentration and the preserved temperature. Under low temperature condition, the solution was more stable than under room temperature preservation. Under the same temperature preservation condition, high concentrations of stock solutions are more stable than low concentrations. The study provides a foundation for preserving the oxytetracycline-methanol solution.

Theoretical investigations on the elastic and thermodynamic properties of Ti2AlC0.5N0.5 solid solution

International Nuclear Information System (INIS)

Du, Y.L.; Sun, Z.M.; Hashimoto, H.; Barsoum, M.W.

2009-01-01

We have performed theoretical studies on the elastic and thermodynamic properties of the solid solution: Ti 2 AlC 0.5 N 0.5 . The lattice parameters, elastic constants, bulk, shear, Young's moduli, Poisson's ratio and Debye temperature were calculated and compared with those of the end members, Ti 2 AlC and Ti 2 AlN. The temperature dependence of the bulk moduli, thermal expansion coefficient and specific heats of Ti 2 AlC 0.5 N 0.5 were obtained from the quasi-harmonic Debye model. The calculated elastic and thermodynamic properties were compared with experimental data.

Study of sandy soil grain-size distribution on its deformation properties

Science.gov (United States)

Antropova, L. B.; Gruzin, A. V.; Gildebrandt, M. I.; Malaya, L. D.; Nikulina, V. B.

2018-04-01

As a rule, new oil and gas fields' development faces the challenges of providing construction objects with material and mineral resources, for example, medium sand soil for buildings and facilities footings of the technological infrastructure under construction. This problem solution seems to lie in a rational usage of the existing environmental resources, soils included. The study was made of a medium sand soil grain-size distribution impact on its deformation properties. Based on the performed investigations, a technique for controlling sandy soil deformation properties was developed.

Geological constraints on the thermodynamic properties of the stilbite - stellerite solid solution in low-grade metabasalts

Science.gov (United States)

Fridriksson, Thráinn; Neuhoff, Philip S.; Arnórsson, Stefán; Bird, Dennis K.

2001-11-01

Standard state thermodynamic data for stilbite (Ca2NaAl5Si13O36∗16H2O) and stellerite (Ca2Al4Si14O36∗14H2O), together with mixing properties of the stilbite -stellerite solid solution (stilbite SS) are derived through assessment of geological observations of stilbite SS compositions in metabasalts, experimental phase equilibria, and calorimetric observations. Measured compositions of stilbite SS in Tertiary metabasalts in Iceland and Icelandic geothermal systems change systematically towards the stellerite endmember with increasing stratigraphic depth and temperature. Standard molal volumes, heat capacities, and entropies for the endmembers of the solid solution are derived through critical review of published crystallographic and calorimetric data for natural stilbite SS. Standard molal Gibbs energies of formation at 298.15 K and 1 bar for stilbite (-4,946,475cal mol-1) and stellerite (-4,762,036 cal mol-1) and the mixing properties of the solid solution are retrieved from observed phase- and compositional-relations in metabasalts at Berufjördur, Iceland, measured temperatures of zeolite mineral distribution in active geothermal systems, and published observations of reversed phase equilibria. Mixing in stilbite SS can be described with an athermal solid solution model. Thermodynamic data resulting from our analysis provide close correlation between compositions of stilbite SS in Icelandic geothermal systems predicted from compositions of geothermal solutions and observed compositions of these minerals in low-grade metabasalts of Iceland, as well as the observed temperature of the stilbite SS to laumontite (leonhardite) transition in Icelandic geothermal systems. Stilbite SS composition in metabasalts is a sensitive function of temperature, fluid composition, coexisting minerals (especially silica polymorphs) and geothermal gradient.

Study of the dosimetric properties using organometallic polymers in solution

International Nuclear Information System (INIS)

Fernandes, David Moreira

2012-01-01

This work aimed to study the dosimetric characteristics of the polymer of the polymer ''poly-[ 1, l-bis (ethynyl) -4,4-biphenyl (bis-tributylphosphine) Pt (11)]'' (Pt-DEBP) compared to radiation gamma. The Pt-DEBP polymer, containing ten monomer units, was then dissolved in organic solvents as chloroform and toluene. The samples were irradiated at four concentrations (0.0500, 0.0375, 0.0250, 0.0113 mg / mL) in duplicate, with radiation doses ranging from 1 to 90 Gy. The results were evaluated based on spectroscopic techniques such as optical absorption spectroscopy (UV -Vis), fluorescence (emission), time resolved fluorescence (FRT) and Fourier transform infrared (FTIR). For DEBP-Pt solutions in chloroform, there is a shift in the position of the main optical absorption band (πt - π*) to lower wavelength (blue-shift), allied to a decreasing absorption intensity with increasing radiation dose. In fluorescence spectroscopy, there was a shift to longer wavelengths (redshift) allied to an increasing emission intensity with increasing radiation dose. FRT experiments on irradiated samples dissolved in chloroform indicated the presence of a new emitter center. FTIR spectra show the incorporation of chlorine in the polymer chain, justifying the blue-shift observed in the absorption spectra and the new emission center. In addition, the behavior of linear results in the absorption and fluorescence studies was investigated based on the relationship between the wavelength of maximum absorption/emission and the radiation dose. For both cases, a linear behavior was observed in relation to the sample concentration. Repeatability and stability tests were also performed. For the samples dissolved in toluene, there was no significant shift of the spectrum of absorption or fluorescence for all doses. The results show that the Pt-DEBP polymer dissolved in chloroform can be used as a dosimeter for x-ray doses between 1 - 30 Gy based on the changes in absorption and/or emission

Effect of solution plasma process with bubbling gas on physicochemical properties of chitosan.

Science.gov (United States)

Ma, Fengming; Li, Pu; Zhang, Baiqing; Zhao, Xin; Fu, Qun; Wang, Zhenyu; Gu, Cailian

2017-05-01

In the present work, solution plasma process (SPP) with bubbling gas was used to prepare oligochitosan. The effect of SPP irradiation with bubbling gas on the degradation of chitosan was evaluated by the intrinsic viscosity reduction rate and the degradation kinetic. The formation of OH radical was studied. Changes of the physicochemical properties of chitosan were measured by scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis, as well as ultraviolet-visible, Fourier-transform infrared, and 13 C nuclear magnetic resonance spectroscopy. The results indicated an obvious decrease in the intrinsic viscosity reduction rate after SPP irradiation with bubbling gas, and that the rate with bubbling was higher than that without. The main chemical structure of chitosan remained intact after irradiation, but changes in the morphology, crystallinity, and thermal stability of oligochitosan were observed. In particular, the crystallinity and thermal stability tended to decrease. The present study indicated that SPP can be effectively used for the degradation of chitosan. Copyright © 2017. Published by Elsevier B.V.

A Study on the Management of Intellectual Property for the Pending Projects in KAERI

International Nuclear Information System (INIS)

Chung, W. S.; Yang, M. H.; Yun, S. W.; Lee, D. S.

2011-01-01

This study is to analysis legal status of intellectual property of the Jordan Researching and Training Reactor(JRTR). To get the goals, researching internal and international laws related with intellectual properties and reviewing the JRTR project are performed. Not only technology itself but also human resources joined the project are considered to find best solution for management. This study will be a good base for the JRTR project itself and other similar projects

Heat treatment versus properties studies associated with the Inconel 718 PBF acoustic filters

International Nuclear Information System (INIS)

Smolik, G.R.; Reuter, W.G.

1975-01-01

PBF acoustic filter Unit No. 1 cracked when heat treatment was attempted. The effects of prior thermal cycling, solution anneal temperature, and cooling rate from solution anneals were investigated. The investigations concerned influences of the above variables upon both 1400 0 F stress rupture solution-annealed properties and room temperature age-hardened properties. 1400 0 F stress rupture properties were of interest to assist the prevention of cracking during heat treatments. Room temperature age-hardened properties were needed to ensure that design requirement would be provided. Prior thermal cycling was investigated to determine if extra thermal cycles would be detrimental to the repaired filter. Slow furnace cools were considered as a means of reducing thermal stresses. Effects of solution annealing at 2000 and 1900 0 F were also determined. Test results showed that slow cooling rates would not only reduce thermal stresses but also improve 1400 0 F ductility. A modified aging treatment was established which provided the required 145 ksi room temperature yield strength for the slowly cooled material. Prior cooling did not degrade final age-hardened room temperature tensile or impact properties

Interactions between Surfactants in Solution and Electrospun Protein Fibers: Effects on Release Behavior and Fiber Properties

DEFF Research Database (Denmark)

Boutrup Stephansen, Karen; García-Díaz, María; Jessen, Flemming

2016-01-01

, and drug delivery. In the present study, we present a systematic investigation of how surfactants and proteins, as physiologically relevant components, interact with insulin-loaded fish sarcoplasmic protein (FSP) electrospun fibers (FSP-Ins fibers) in solution and thereby affect fiber properties...... such as accessible surface hydrophilicity, physical stability, and release characteristics of an encapsulated drug. Interactions between insulin-loaded protein fibers and five anionic surfactants (sodium taurocholate, sodium taurodeoxycholate, sodium glycocholate, sodium glycodeoxycholate, and sodium dodecyl sulfate......), a cationic surfactant (benzalkonium chloride), and a neutral surfactant (Triton X-100) were studied. The anionic surfactants increased the insulin release in a concentration-dependent manner, whereas the neutral surfactant had no significant effect on the release. Interestingly, only minute amounts...

Influence of pH of spray solution on optoelectronic properties of cadmium oxide thin films

International Nuclear Information System (INIS)

Hodlur, R. M.; Rabinal, M. K.

2015-01-01

Highly conducting transparent cadmium oxide thin films were prepared by the conventional spray pyrolysis technique. The pH of the spray solution is varied by adding ammonia/hydrochloric acid. The effect of pH on the morphology, crystallinity and optoelectronic properties of these films is studied. The structural analysis showed all the films in the cubic phase. For the films with pH < 7 (acidic condition), the preferred orientation is along the (111) direction and for those with pH >7 (alkaline condition), the preferred orientation is along the (200) direction. A lowest resistivity of 9.9 × 10 −4 Ω·cm (with carrier concentration = 5.1 × 10 20 cm −3 , mobility = 12.4 cm 2 /(V·s)) is observed for pH ≈ 12. The resistivity is tuned almost by three orders of magnitude by controlling the bath pH with optical transmittance more than 70%. Thus, the electrical conductivity of CdO films could be easily tuned by simply varying the pH of the spray solution without compromising the optical transparency. (paper)

Effect of Soaking Time in Sodium Metabisulfite Solution on the Physicochemical and Functional Properties of Durian Seed Flour

Directory of Open Access Journals (Sweden)

Kumoro Andri

2018-01-01

Full Text Available With regard to its high carbohydrate and gum contents, durian seed flour has been used as a substitute to wheat flour in butter cake and cookies manufactures. Unfortunately, processing of fruit seeds into flour may be hampered by discoloration, which may affect the nutrition and sensory quality of the food products. The objective of this study is to investigate the effect of soaking time on the physicochemical and functional properties of durian seed flour. Durian seed chips were soaked in 0.6% w/v sodium metabisulfite solution as anti-browning agent at 30°C for desired periods (40, 60, 80, 100, 120 minutes, followed by drying at 50°C for 17 hours, milling and sieving to obtain flour. The flour was analyzed for its moisture, ash, protein, fat and carbohydrate contents, sulfite residue, yield, gelatinization temperature, and water and oil absorption capacities (WAC and OAC. The results showed that longer soaking time reduced the moisture and ash content of durian seed flour, but increased most of the other studied parameters. The WAC, OAC and fat content were less affected by soaking time. It can be concluded that soaking of durian seed chips in sodium metabisulfite solution can improve the nutrition and functional properties of flour. Based on the residual sulfite content, durian seed flour obtained in this work is safe for consumption.

THERMODYNAMIC PROPERTIES OF NONAQUEOUS SINGLE SALT SOLUTIONS USING THE Q-ELECTROLATTICE EQUATION OF STATE

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A. Zuber

2015-09-01

Full Text Available AbstractThe correlation of thermodynamic properties of nonaqueous electrolyte solutions is relevant to design and operation of many chemical processes, as in fertilizer production and the pharmaceutical industry. In this work, the Q-electrolattice equation of state (EOS is used to model vapor pressure, mean ionic activity coefficient, osmotic coefficient, and liquid density of sixteen methanol and ten ethanol solutions containing single strong 1:1 and 2:1 salts. The Q-electrolattice comprises the lattice-based Mattedi-Tavares-Castier (MTC EOS, the Born term and the explicit MSA term. The model requires two adjustable parameters per ion, namely the ionic diameter and the solvent-ion interaction energy. Predictions of osmotic coefficient at 298.15 K and liquid density at different temperatures are also presented.

Influence of activating solution and the addition of NaF on metakaolin-based geopolymer physico-chemical properties

International Nuclear Information System (INIS)

Agullo, J.; Muzeau, B.; Trepy, N.; L'Hostis, V.; Lambertin, D.

2015-01-01

The technology of geo-polymerisation is attracting a lot of interest due to the wide variety of potential applications. Recently emerging and alternative cementitious systems based on geo-polymers have been reported in literature. Geo-polymer materials have been proposed as new binders for safe radioactive waste containment. Moreover, their good fluidity and fire resistance make them compatible with industrial processes for embedding wastes. The purpose of this work was to investigate the physico-chemical properties of meta-kaolin-based geo-polymer which could be used as mineral binder for encapsulation of metallic nuclear wastes. To improve the knowledge of this binder, its microstructure and its interstitial solution have been characterized during hydration (up to 28 days). Interstitial solutions were extracted at different hydration time and subsequent analyses allow us to determine their chemical composition. pH measurements confirm the high alkalinity of the interstitial pore solution. The influence of the activating solution (NaOH or KOH) and the addition of NaF as corrosion inhibitor in the geo-polymer composition were also studied. The nature of different crystalline phases was identified by X-ray diffraction. Water accessible porosity for these materials was estimated around 59%. The pore size distribution was determined by mercury intrusion porosity. Alkaline cations have proved to induce changes in the pore size distribution, these ones coming from whether the activating solution or the NaF addition. (authors)

Study of micelle formation in solutions of alkylammonium carboxylates in apolar solvents by positron annihilation techniques

International Nuclear Information System (INIS)

Fucugauchi, L.A.; Djermouni, B.; Handel, E.D.; Ache, H.J.

1979-01-01

The positron annihilation technique was applied to the study of the self-association process in solutions of alkylammonium carboxylates in apolar solvents, such as cyclohexane and benzene. The results indicate that the positronium formation probability responds very sensitively to changes in the microenvironment in these solutions. A distinct cooperative effect of the solution resulting in abrupt changes in the number of thermal ortho-positronium atoms formed was observed and studied as a function of the length and structure of the hydrocarbon chain in the cationic and anionic parts of the surfactant molecules. While the chain length in the cationic portion of the surfactant seems to have little effect on the positronium formation probability, distinct differences can be observed when the structure of the carboxylate is changed. Furthermore, a profound effect in the physical property of the solutions was recognized when cyclohexane was replaced by benzene as a solvent. The results are discussed in terms of the existing models for self-association. 4 figures

Conformation and arrangement of polyelectrolytes in semi-diluted solution. A study by small angle neutrons scattering; Conformation et arrangement des polyelectrolytes en solution semi-diluee. Etude par diffusion des neutrons aux petits angles

Energy Technology Data Exchange (ETDEWEB)

Spiteri, M N

1997-03-25

Polyelectrolytes have particular physical and chemical properties and can thus be used for instance for petroleum production. Some of their microscopic properties have been studied in this work. With the particular zero average contrast technique, the small angle neutron scattering allows to directly know the form factors in semi-diluted solutions of polyelectrolytes where the chains are mixed. Another measure leads to the crystal structure. The electrostatic screen effects when salt is added in aqueous solutions of completely charged PSSNa solutions (f=1) (sodium polystyrene sulfonate) are studied. It seems that the chains take a vermiform conformation. Their persistence length varies as I{sup -1/3} (I is the ionic force). The hydrophobicity effects in partially charged PSSNa solutions (f<1) are given too. They lead to a progressive collapse of the chains when their charge rates decrease. The screen and condensation effects when the charge rate f of the PSSNa (f>f(Manning)) varies in a polar solvent (DMSO) are studied. The vermiform chains have the same persistence length (for each f) which varies as I{sup -1/4}. Lastly, the f variation effects in the case of a weakly charged hydrophilic poly-ion (f

Study of two examples of non linear interaction of a laser wave with matter: laser-induced damage of dielectrics and non linear optical properties of organometallic molecules in solution

International Nuclear Information System (INIS)

Gaudry, Jean-Baptiste

2000-01-01

This research thesis reports the study of two mechanisms of non linear interaction of a laser wave with matter. More particularly, it reports the experimental investigation of non linear optical properties of organometallic molecules in solution, as well as the damage of perfect silica under laser irradiation by using simulation codes. As far as optical properties are concerned, the author highlights the influence of the electronic configuration of the metal present in the organometallic compound, and the influence of the ligand on the second-order non-linear response. As far as the simulation is concerned, some experimental results have been reproduced. This work can be useful for the investigation of the extrinsic damage of imperfect materials, and for the design of experiments of transient measurements of excited silica [fr

Hemoglobin bioconjugates with surface-protected gold nanoparticles in aqueous media: The stability depends on solution pH and protein properties.

Science.gov (United States)

Del Caño, Rafael; Mateus, Lucia; Sánchez-Obrero, Guadalupe; Sevilla, José Manuel; Madueño, Rafael; Blázquez, Manuel; Pineda, Teresa

2017-11-01

The identification of the factors that dictate the formation and physicochemical properties of protein-nanomaterial bioconjugates are important to understand their behavior in biological systems. The present work deals with the formation and characterization of bioconjugates made of the protein hemoglobin (Hb) and gold nanoparticles (AuNP) capped with three different molecular layers (citrate anions (c), 6-mercaptopurine (MP) and ω-mercaptoundecanoic acid (MUA)). The main focus is on the behavior of the bioconjugates in aqueous buffered solutions in a wide pH range. The stability of the bioconjugates have been studied by UV-visible spectroscopy by following the changes in the localized surface resonance plasmon band (LSRP), Dynamic light scattering (DLS) and zeta-potential pH titrations. It has been found that they are stable in neutral and alkaline solutions and, at pH lower than the protein isoelectric point, aggregation takes place. Although the surface chemical properties of the AuNPs confer different properties in respect to colloidal stability, once the bioconjugates are formed their properties are dictated by the Hb protein corona. The protein secondary structure, as analyzed by Attenuated total reflectance infrared (ATR-IR) spectroscopy, seems to be maintained under the conditions of colloidal stability but some small changes in protein conformation take place when the bioconjugates aggregate. These findings highlight the importance to keep the protein structure upon interaction with nanomaterials to drive the stability of the bioconjugates. Copyright © 2017 Elsevier Inc. All rights reserved.

Tensometrical properties of volumetric crystals of germanium-silicon solid solutions irradiated by fast electrons

International Nuclear Information System (INIS)

Abbasov, Sh.M.

2002-01-01

Full Text: In the present work the tensometrical properties of Ge1-xSix solid solution monocrystal contended of up to 15 at. % Si were investigated. The radiation-proof strain gauges of researched crystals were made. For this purpose the site was cutted out from a sample, perpendicularly or in parallel of a crystal axes. After polishing the samples had thickness of 30-40 microns, and length of 2 mm

Influence of complexing on physicochemical properties of polymer-salt solutions

International Nuclear Information System (INIS)

Ostroushko, A.A.; Yushkova, S.M.; Koridze, N.V.; Skobkoreva, N.V.; Zhuravleva, L.I.; Palitskaya, T.A.; Antropova, S.V.; Ostroushko, I.P.; AN SSSR, Moscow

1993-01-01

Using the methods of spectrophotometry, viscosimetry, conductometry the influence of salt-polymer complexing processes on physicochemical prperties of aqueous solutions of yttrium, barium, copper nitrates and formates with polyvinyl alcohol was studied. Change of dynamic viscosity, specific electric conductivity of solutions in the process of complexing was shown. Thermal effects of salt-polymer interaction were measured. It is shown that decrease of transition temperature of polymer to plastic state in films, temperature and effective activation energy of salt decomposition is also connected with complexing. Effective values of surface tension on the boundary with air are measured. Coefficients of cation diffusion in polymer-salt solutions are estimated

Aqueous solutions that model the cytosol : studies on polarity, chemical reactivity and enzyme kinetics

NARCIS (Netherlands)

Asaad, N.; den Otter, M.J.; Engberts, J.B.F.N.

2004-01-01

Concentrated solutions of a series of organic compounds have been prepared and the effects of these solutes on the properties of the solvent system assessed as a function of their concentration and nature. Polarity, as measured by Reichardt's E-T(30) probe, exhibits a linear variation with both

Solid solution barium–strontium chlorides with tunable ammonia desorption properties and superior storage capacity

Energy Technology Data Exchange (ETDEWEB)

Bialy, Agata [Amminex Emissions Technology A/S, Gladsaxevej 363, 2860 Soeborg (Denmark); Jensen, Peter B. [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Center for Atomic-scale Materials Design, Department of Physics, Technical University of Denmark, Fysikvej 311, DK-2800 Kgs. Lyngby (Denmark); Blanchard, Didier [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Vegge, Tejs, E-mail: teve@dtu.dk [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Quaade, Ulrich J., E-mail: ujq@amminex.com [Amminex Emissions Technology A/S, Gladsaxevej 363, 2860 Soeborg (Denmark)

2015-01-15

Metal halide ammines are very attractive materials for ammonia absorption and storage—applications where the practically accessible or usable gravimetric and volumetric storage densities are of critical importance. Here we present, that by combining advanced computational materials prediction with spray drying and in situ thermogravimetric and structural characterization, we synthesize a range of new, stable barium-strontium chloride solid solutions with superior ammonia storage densities. By tuning the barium/strontium ratio, different crystallographic phases and compositions can be obtained with different ammonia ab- and desorption properties. In particular it is shown, that in the molar range of 35–50% barium and 65–50% strontium, stable materials can be produced with a practically usable ammonia density (both volumetric and gravimetric) that is higher than any of the pure metal halides, and with a practically accessible volumetric ammonia densities in excess of 99% of liquid ammonia. - Graphical abstract: Thermal desorption curves of ammonia from Ba{sub x}Sr{sub (1−x)}Cl{sub 2} mixtures with x equal to 0.125, 0.25 and 0.5 and atomic structure of Sr(NH{sub 3}){sub 8}Cl{sub 2}. - Highlights: • Solid solutions of strontium and barium chloride were synthesized by spray drying. • Adjusting molar ratios led to different crystallographic phases and compositions. • Different molar ratios led to different ammonia ab-/desorption properties. • 35–50 mol% BaCl{sub 2} in SrCl{sub 2} yields higher ammonia density than any other metal halide. • DFT calculations can be used to predict properties of the mixtures.

Comparative acid-base properties of the surface of components of the CdTe-ZnS system in series of substitutional solid solutions and their analogs

Science.gov (United States)

Kirovskaya, I. A.; Kasatova, I. Yu.

2011-07-01

The acid-base properties of the surface of solid solutions and binary components of the CdTe-ZnS system are studied by hydrolytic adsorption, nonaqueous conductometric titration, mechanochemistry, IR spectroscopy, and Raman scattering spectroscopy. The strength, nature, and concentration of acid centers on the original surface and that exposed to CO are determined. The changes in acid-base properties in dependence on the composition of the system under investigation in the series of CdB6, ZnB6 analogs are studied.

Effect of indium on photovoltaic property of n-ZnO/p-Si heterojunction device prepared using solution-synthesized ZnO nanowire film

Science.gov (United States)

Kathalingam, Adaikalam; Kim, Hyun-Seok; Park, Hyung-Moo; Valanarasu, Santiyagu; Mahalingam, Thaiyan

2015-01-01

Preparation of n-ZnO/p-Si heterostructures using solution-synthesized ZnO nanowire films and their photovoltaic characterization is reported. The solution-grown ZnO nanowire film is characterized using scanning electron microscope, electron dispersive x-ray, and optical absorption studies. Electrical and photovoltaic properties of the fabricated heterostructures are studied using e-beam-evaporated aluminum as metal contacts. In order to use transparent contact and to simultaneously collect the photogenerated carriers, sandwich-type solar cells were fabricated using ZnO nanorod films grown on p-silicon and indium tin oxide (ITO) coated glass as ITO/n-ZnO NR/p-Si. The electrical properties of these structures are analyzed from current-voltage (I-V) characteristics. ZnO nanowire film thickness-dependent photovoltaic properties are also studied. Indium metal was also deposited over the ZnO nanowires and its effects on the photovoltaic response of the devices were studied. The results demonstrated that all the samples exhibit a strong rectifying behavior indicating the diode nature of the devices. The sandwich-type ITO/n-ZnO NR/p-Si solar cells exhibit improved photovoltaic performance over the Al-metal-coated n-ZnO/p-Si structures. The indium deposition is found to show enhancement in photovoltaic behavior with a maximum open-circuit voltage (Voc) of 0.3 V and short-circuit current (Isc) of 70×10-6 A under ultraviolet light excitation.

Prediction of thermodynamic properties of solute elements in Si solutions using first-principles calculations

International Nuclear Information System (INIS)

Iwata, K.; Matsumiya, T.; Sawada, H.; Kawakami, K.

2003-01-01

The method is presented to predict the activity coefficients and the interaction parameters of the solute elements in infinite dilute Si solutions by the use of first-principles calculations based on density functional theory. In this method, the regular solution model is assumed. The calculated activity coefficients in solid Si are converted to those in molten Si by the use of the solid-liquid partition coefficients. Furthermore, the interaction parameters in solid Si solutions are calculated and compared with reported experimental values of those in liquid Si solutions. The results show that the calculated activity coefficients and interaction parameters of Al, Fe, Ti and Pb in Si solutions are in good agreement with the tendency of the experiments. However, the calculations have some quantitative discrepancy from the experiments. It is expected that consideration of the excess entropy would reduce this discrepancy

Montmorillonite surface properties and sorption characteristics for heavy metal removal from aqueous solutions

International Nuclear Information System (INIS)

Ijagbemi, Christianah Olakitan; Baek, Mi-Hwa; Kim, Dong-Su

2009-01-01

Surface properties of montmorillonite (MMT) and its adsorption characteristics for heavy metals have been investigated with nickel and copper as sorbate from aqueous solutions. Employing the potentiometric and mass titration techniques in batch experimental methods, the point of zero charge (PZC) and point of zero net proton charge (PZNPC) of MMT edges at different ionic strengths present pH PZC and pH PZNPC to be 3.4 ± 0.2. A crossing point was observed for the proton adsorption vs. pH curves at different ionic strengths of KCl electrolyte and in investigating MMT remediation potentialities as sorbent for heavy metals polluted waters, the effects of heavy metal concentration, pH, MMT dosage, reaction time and temperature for Cu 2+ and Ni 2+ uptake were studied. The sorption of metal ions by MMT was pH dependent and the adsorption kinetics revealed sorption rate could be well fitted by the pseudo-second-order rate model. The data according to mass transfer and intraparticle diffusion models confirmed diffusion of solutes inside the clay particles as the rate-controlling step and more important for the adsorption rate than the external mass transfer. Adsorption isotherms showed that the uptake of Cu 2+ and Ni 2+ could be described by the Langmuir model and from calculations on thermodynamic parameters, the positive ΔG o values at different temperatures suggest that the sorption of both metal ions were non-spontaneous. Change in enthalpy (ΔH o ) for Ni 2+ and Cu 2+ were 28.9 and 13.27 kJ/mol K respectively, hence an endothermic diffusion process, as ion uptake increased with increase in temperature. Values of ΔS o indicate low randomness at the solid/solution interface during the uptake of both Cu 2+ and Ni 2+ by MMT. Montmorillonite has a considerable potential for the removal of heavy metal cationic species from aqueous solution and wastewater.

Rheological properties of poly-vinyl-chloride solutions in varioussolvents

International Nuclear Information System (INIS)

Kurbanaliev, M.K.; Narzullaev, B.N.; Dustov, I.K.; Marupov, R.M.

1976-01-01

The present article is the result of studying of curves process ofpoly-vinyl-chloride solutions in wide interval of tension and velocities ofshear in thermodynamically good and bad solvents at various temperatures

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.

An approach to the research on ion and water properties in the interphase between the plasma membrane and bulk extracellular solution.

Science.gov (United States)

Hibino, Hiroshi; Takai, Madoka; Noguchi, Hidenori; Sawamura, Seishiro; Takahashi, Yasufumi; Sakai, Hideki; Shiku, Hitoshi

2017-07-01

In vivo, cells are immersed in an extracellular solution that contains a variety of bioactive substances including ions and water. Classical electrophysiological analyses of epithelial cells in the stomach and small intestine have revealed that within a distance of several hundred micrometers above their apical plasma membrane, lies an extracellular layer that shows ion concentration gradients undetectable in the bulk phase. This "unstirred layer", which contains stagnant solutes, may also exist between the bulk extracellular solution and membranes of other cells in an organism and may show different properties. On the other hand, an earlier study using a bacterial planar membrane indicated that H + released from a transporter migrates in the horizontal direction along the membrane surface much faster than it diffuses vertically toward the extracellular space. This result implies that between the membrane surface and unstirred layer, there is a "nanointerface" that has unique ionic dynamics. Advanced technologies have revealed that the nanointerface on artificial membranes possibly harbors a highly ordered assembly of water molecules. In general, hydrogen bonds are involved in formation of the ordered water structure and can mediate rapid transfer of H + between neighboring molecules. This description may match the phenomenon on the bacterial membrane. A recent study has suggested that water molecules in the nanointerface regulate the gating of K + channels. Here, the region comprising the unstirred layer and nanointerface is defined as the interphase between the plasma membrane and bulk extracellular solution (iMES). This article briefly describes the physicochemical properties of ions and water in the iMES and their physiological significance. We also describe the methodologies that are currently used or will be applicable to the interphase research.

Open Access Intellectual Property Systems: A Comparison to Commercial Solutions in Competitive Intelligence

Directory of Open Access Journals (Sweden)

Jan Cerny

2016-07-01

Full Text Available ICT/IS management plays an important role within the framework of innovation management, and one of the key elements of this role is the support of Competitive Intelligence in the context of innovation processes. The strategic information needs of innovation management are also directed towards different kinds of intellectual property (IP information entities and commercialization. The purpose of this paper is to define these entities and IP information systems as an important part of a company’s Competitive Intelligence Unit for competitor analysis and technology trends. The open access IP information systems will be analysed together with commercial solutions.. The aim of this paper is to underline the importance of open access IP systems compared to added value commercial solutions for competitive intelligence purposes for SMEs. The comparison will be carried out using examples of patent searches within a concrete dataset.

Using Micromechanical Resonators to Measure Rheological Properties and Alcohol Content of Model Solutions and Commercial Beverages

Directory of Open Access Journals (Sweden)

Bart W. Hoogenboom

2012-05-01

Full Text Available Micromechanic resonators provide a small-volume and potentially high-throughput method to determine rheological properties of fluids. Here we explore the accuracy in measuring mass density and viscosity of ethanol-water and glycerol-water model solutions, using a simple and easily implemented model to deduce the hydrodynamic effects on resonating cantilevers of various length-to-width aspect ratios. We next show that these measurements can be extended to determine the alcohol percentage of both model solutions and commercial beverages such as beer, wine and liquor. This demonstrates how micromechanical resonators can be used for quality control of every-day drinks.

Study on the acid-base surface property of the magnetite graphene oxide and its usage for the removal of radiostrontium from aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Chen, H.; Li, J.X.; Zhang, S.W.; Ren, X.M.; Sun, Y.B.; Wen, T.; Wang, X.K. [Chinese Academy of Sciences, Hefei (China). Key Laboratory of Novel Thin Film Solar Cells

2013-07-01

Acid-base titrations of magnetite/graphene oxide (M/GO) and Sr(II) adsorption onto M/GO were operated to investigate surface properties of M/GO and surface complexation bonding interactions between Sr(II) and M/GO. Experimental results showed that Sr(II) adsorption onto M/GO was facilitated by a high pH value and a low ionic strength. Modeling results exhaustively explained the changes of adsorption morphological at different pH and ionic strengths. Thermodynamic parameters ({Delta}H , {Delta}S , and {Delta}G ) calculated from the adsorption isotherms showed the adsorption of Sr(II) onto M/GO composite was an endothermic and spontaneous process. M/GO could be separated by magnetic separation from aqueous solution in large scale. The adsorption performance suggests M/GO could be a promising adsorbent material for the preconcentration and separation of radiostrontium from aqueous solution in radionuclide pollution cleanup. (orig.)

On Some New Properties of the Fundamental Solution to the Multi-Dimensional Space- and Time-Fractional Diffusion-Wave Equation

Directory of Open Access Journals (Sweden)

Yuri Luchko

2017-12-01

Full Text Available In this paper, some new properties of the fundamental solution to the multi-dimensional space- and time-fractional diffusion-wave equation are deduced. We start with the Mellin-Barnes representation of the fundamental solution that was derived in the previous publications of the author. The Mellin-Barnes integral is used to obtain two new representations of the fundamental solution in the form of the Mellin convolution of the special functions of the Wright type. Moreover, some new closed-form formulas for particular cases of the fundamental solution are derived. In particular, we solve the open problem of the representation of the fundamental solution to the two-dimensional neutral-fractional diffusion-wave equation in terms of the known special functions.

Photochemical properties of Ysub(t) base in aqueous solution

International Nuclear Information System (INIS)

Paszyc, S.; Rafalska, M.

1979-01-01

Photoreactivity of Ysub(t) base (I) has been studied in aqueous solution (pH-6) saturated with oxygen. Two photoproducts (II,III), resulting from irradiation at lambda = 253.7 nm and lambda >= 290 nm were isolated and their structures determined. The quantum yield for Ysub(t) base disappearance (rho dis) is 0.002 (lambda = 313 nm). It was shown that dye- sensitised photo-oxidation of Ysub(t) base in aqueous solution occurs according to a Type I mechanism as well as with participation of singlet state oxygen. Quantum yields, fluorescence decay times and phosphorescence of Ysub(t) base have also been determined. (author)

Diffusion of aqueous solutions of ionic, zwitterionic, and polar solutes

Science.gov (United States)

Teng, Xiaojing; Huang, Qi; Dharmawardhana, Chamila Chathuranga; Ichiye, Toshiko

2018-06-01

The properties of aqueous solutions of ionic, zwitterionic, and polar solutes are of interest to many fields. For instance, one of the many anomalous properties of aqueous solutions is the behavior of water diffusion in different monovalent salt solutions. In addition, solutes can affect the stabilities of macromolecules such as proteins in aqueous solution. Here, the diffusivities of aqueous solutions of sodium chloride, potassium chloride, tri-methylamine oxide (TMAO), urea, and TMAO-urea are examined in molecular dynamics simulations. The decrease in the diffusivity of water with the concentration of simple ions and urea can be described by a simple model in which the water molecules hydrogen bonded to the solutes are considered to diffuse at the same rate as the solutes, while the remainder of the water molecules are considered to be bulk and diffuse at almost the same rate as pure water. On the other hand, the decrease in the diffusivity of water with the concentration of TMAO is apparently affected by a decrease in the diffusion rate of the bulk water molecules in addition to the decrease due to the water molecules hydrogen bonded to TMAO. In other words, TMAO enhances the viscosity of water, while urea barely affects it. Overall, this separation of water molecules into those that are hydrogen bonded to solute and those that are bulk can provide a useful means of understanding the short- and long-range effects of solutes on water.

Catalytic properties of lanthanide amide, imide and nitride formed by thermal degradation of liquid ammonia solutions of Eu and Yb metal

International Nuclear Information System (INIS)

Imamura, H.; Mizuno, K.; Ohishi, K.; Suda, E.; Kanda, K.; Sakata, Y.; Tsuchiya, S.

1998-01-01

The catalytic properties of lanthanide amide, imide and nitride prepared by the use of liquid ammonia solutions of lanthanide metals (Ln=Eu and Yb) were studied for catalytic hydrogenation. The reaction of Eu or Yb metal solutions in liquid ammonia with silica yielded SiO 2 -grafted lanthanide amide in the divalent state. The divalent amide showed catalytic activity for the selective hydrogenation of dienes and benzene. It was found that partial hydrogenation of benzene occurred with a very high selectivity for cyclohexene. Amides of calcium, strontium and barium were examined similarly in connection with catalytic studies on divalent amides. Imide and nitride, into which the lanthanide (Ln/AC) deposited by impregnation of active carbon (AC) with liquid ammonia solutions of lanthanide metals were converted thermally, were studied catalytically. It was concluded that imide or imide-like species generated during the thermal degradation of lanthanide amide to nitride were very active in the hydrogenation of ethene. Lanthanide nitride was virtually inactive, but the nitride highly dispersed on active carbon was activated when subjected to evacuation treatment above about 1000 K. (orig.)

Properties of ZnO:Al Films Prepared by Spin Coating of Aged Precursor Solution

International Nuclear Information System (INIS)

Shrestha, Shankar Prasad; Ghimire, Rishi; Nakarmi, Jeevan Jyoti; Kim, Young Sung; Shrestha, Sabita; Park, Chong Yun; Boo, Jin Hyo

2010-01-01

Transparent conducting undoped and Al impurity doped ZnO films were deposited on glass substrate by spin coat technique using 24 days aged ZnO precursor solution with solution of ethanol and diethanolamine. The films were characterized by UV-Visible spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), electrical resistivity (ρ), carrier concentration (n), and hall mobility (μ) measurements. XRD data show that the deposited film shows polycrystalline nature with hexagonal wurtzite structure with preferential orientation along (002) crystal plane. The SEM images show that surface morphology, porosity and grain sizes are affected by doping concentration. The Al doped samples show high transmittance and better resistivity. With increasing Al concentration only mild change in optical band gap is observed. Optical properties are not affected by aging of parent solution. A lowest resistivity (8.5 x 10 -2 ohm cm) is observed at 2 atomic percent (at.%) Al. With further increase in Al concentration, the resistivity started to increase significantly. The decrease resistivity with increasing Al concentration can be attributed to increase in both carrier concentration and hall mobility

The applications of small-angle X-ray scattering in studying nano-scaled polyoxometalate clusters in solutions

Science.gov (United States)

Li, Mu; Zhang, Mingxin; Wang, Weiyu; Cheng, Stephen Z. D.; Yin, Panchao

2018-05-01

Nano-scaled polyoxometalates (POMs) clusters with sizes ranging from 1 to 10 nm attract tremendous attention and have been extensively studied due to POMs' fascinating structural characteristics and prospects for wide-ranging applications. As a unique class of nanoparticles with well-defined structural topologies and monodispersed masses, the structures and properties of POMs in both bulk state and solutions have been explored with several well-developed protocols. Small-angle X-ray scattering (SAXS) technique, as a powerful tool for studying polymers and nanoparticles, has been recently extended to the investigating of solution behaviors of POMs. In this mini-review, the general principle and typical experimental procedures of SAXS are illustrated first. The applications of SAXS in characterizing POMs' morphology, counterion distribution around POMs, and short-range interactions among POMs in solutions are highlighted. [Figure not available: see fulltext.

Study of micellar solutions of the 'sodium lauryl sulphate-heavy water' system by using pulsed NMR

International Nuclear Information System (INIS)

Fouchet, C.

1972-01-01

This research thesis reports the study of the nuclear magnetic resonance of protons contained by micellar solutions of sodium lauryl sulphate and heavy water. Relaxation times have been measured with respect to various parameters: concentration, temperature, frequency. The author presents the main properties of micellar solutions and indicate the various possible movements. Then, he addresses the implemented technique, and shows that NMR is sensitive to short range interactions, and allows micellar movements to be studied over an extended rate range. Experimental results are then presented and interpreted [fr

Anisotropic surface hole-transport property of triphenylamine-derivative single crystal prepared by solution method

Energy Technology Data Exchange (ETDEWEB)

Umeda, Minoru, E-mail: mumeda@vos.nagaokaut.ac.jp [Nagaoka University of Technology, Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Katagiri, Mitsuhiko; Shironita, Sayoko [Nagaoka University of Technology, Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Nagayama, Norio [Nagaoka University of Technology, Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Ricoh Company, Ltd., Nishisawada, Numazu, Shizuoka 410-0007 (Japan)

2016-12-01

Highlights: • A hole transport molecule was investigated based on its electrochemical redox characteristics. • The solubility and supersolubility curves of the molecule were measured in order to prepare a large crystal. • The polarization micrograph and XRD results revealed that a single crystal was obtained. • An anisotropic surface conduction, in which the long-axis direction exceeds that of the amorphous layer, was observed. • The anisotropic surface conduction was well explained by the molecular stacked structure. - Abstract: This paper reports the anisotropic hole transport at the triphenylamine-derivative single crystal surface prepared by a solution method. Triphenylamine derivatives are commonly used in a hole-transport material for organic photoconductors of laser-beam printers, in which the materials are used as an amorphous form. For developing organic photovoltaics using the photoconductor’s technology, preparation of a single crystal seems to be a specific way by realizing the high mobility of an organic semiconductor. In this study, a single crystal of 4-(2,2-diphenylethenyl)-N,N-bis(4-methylphenyl)-benzenamine (TPA) was prepared and its anisotropic hole-transport property measured. First, the hole-transport property of the TPA was investigated based on its chemical structure and electrochemical redox characteristics. Next, a large-scale single crystal formation at a high rate was developed by employing a solution method based on its solubility and supersolubility curves. The grown TPA was found to be a single crystal based on the polarization micrograph observation and crystallographic analysis. For the TPA single crystal, an anisotropic surface conduction was found, which was well explained by its molecular stack structure. The measured current in the long-axis direction is one order of magnitude greater than that of amorphous TPA.

Self-assembly of block copolymer micelles: synthesis via reversible addition-fragmentation chain transfer polymerization and aqueous solution properties.

Science.gov (United States)

Mya, Khine Y; Lin, Esther M J; Gudipati, Chakravarthy S; Gose, Halima B A S; He, Chaobin

2010-07-22

Poly(hexafluorobutyl methacrylate) (PHFBMA) homopolymer was synthesized by reversible addition-fragmentation chain transfer (RAFT)-mediated living radical polymerization in the presence of cyano-2-propyl dithiobenzoate (CPDB) RAFT agent. A block copolymer of PHFBMA-poly(propylene glycol acrylate) (PHFBMA-b-PPGA) with dangling poly(propylene glycol) (PPG) side chains was then synthesized by using CPDB-terminated PHFBMA as a macro-RAFT agent. The amphiphilic properties and self-assembly of PHFBMA-b-PPGA block copolymer in aqueous solution were investigated by dynamic and static light scattering (DLS and SLS) studies, in combination with fluorescence spectroscopy and transmission electron microscopy (TEM). Although PPG shows moderately hydrophilic character, the formation of nanosize polymeric micelles was confirmed by fluorescence and TEM studies. The low value of the critical aggregation concentration exhibited that the tendency for the formation of copolymer aggregates in aqueous solution was very high due to the strong hydrophobicity of the PHFBMA(145)-b-PPGA(33) block copolymer. The combination of DLS and SLS measurements revealed the existence of micellar aggregates in aqueous solution with an association number of approximately 40 +/- 7 for block copolymer micelles. It was also found in TEM observation that there are 40-50 micelles accumulated into one aggregate and these micelles are loosely packed inside the aggregate.

Lagrangian theory with zero component. Application to the study of the polymers in solution (chains with exclued volume) and of the properties of electrons in a random potential

International Nuclear Information System (INIS)

Des Cloizeaux, J.

1976-01-01

The Lagrangian theory of a field with n components can be generalized for values of n which are not integers and in particular for n=0. This extension is made by introducing ordered Green's functions. It is shown how the zero components Lagrangian theory can be used to describe the behaviour of an isolated polymer or of a solution of polymers with large molecular masses. It is remarked that by analytic continuation with respect to the coupling constant, it should be possible to study the properties of electrons in a random potential and perhaps the nature of the mobility edges [fr

Phase Behaviour and Miscibility Studies of Collagen/Silk Fibroin Macromolecular System in Dilute Solutions and Solid State.

Science.gov (United States)

Ghaeli, Ima; de Moraes, Mariana A; Beppu, Marisa M; Lewandowska, Katarzyna; Sionkowska, Alina; Ferreira-da-Silva, Frederico; Ferraz, Maria P; Monteiro, Fernando J

2017-08-18

Miscibility is an important issue in biopolymer blends for analysis of the behavior of polymer pairs through the detection of phase separation and improvement of the mechanical and physical properties of the blend. This study presents the formulation of a stable and one-phase mixture of collagen and regenerated silk fibroin (RSF), with the highest miscibility ratio between these two macromolecules, through inducing electrostatic interactions, using salt ions. For this aim, a ternary phase diagram was experimentally built for the mixtures, based on observations of phase behavior of blend solutions with various ratios. The miscibility behavior of the blend solutions in the miscible zones of the phase diagram was confirmed quantitatively by viscosimetric measurements. Assessing the effects of biopolymer mixing ratio and salt ions, before and after dialysis of blend solutions, revealed the importance of ion-specific interactions in the formation of coacervate-based materials containing collagen and RSF blends that can be used in pharmaceutical, drug delivery, and biomedical applications. Moreover, the conformational change of silk fibroin from random coil to beta sheet, in solution and in the final solid films, was detected by circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR), respectively. Scanning electron microscopy (SEM) exhibited alterations of surface morphology for the biocomposite films with different ratios. Surface contact angle measurement illustrated different hydrophobic properties for the blended film surfaces. Differential scanning calorimetry (DSC) showed that the formation of the beta sheet structure of silk fibroin enhances the thermal stability of the final blend films. Therefore, the novel method presented in this study resulted in the formation of biocomposite films whose physico-chemical properties can be tuned by silk fibroin conformational changes by applying different component mixing ratios.

Effect of Solution Treatment on Precipitation Behaviors, Age Hardening Response and Creep Properties of Elektron21 Alloy Reinforced by AlN Nanoparticles.

Science.gov (United States)

Saboori, Abdollah; Padovano, Elisa; Pavese, Matteo; Dieringa, Hajo; Badini, Claudio

2017-12-02

In the present study, the solution and ageing treatments behavior of Mg-RE-Zr-Zn alloy (Elektron21) and its nano-AlN reinforced nanocomposites have been evaluated. The properties of the thermal-treated materials were investigated in terms of Vickers hardness, the area fraction of precipitates, microstructure and phase composition. The solution treatments were performed by treating at 520 °C, 550 °C and 580 °C in argon atmosphere. The outcomes show that the hardness of the solutionized alloys was slightly affected by the solution temperature. X-ray diffraction and image analysis revealed that the complete dissolution of precipitates was not possible, neither for Elektron21 (El21) nor for its AlN containing nanocomposites. The ageing treatment of El21 led to a significant improvement in hardness after 20 h, while for longer times, it progressively decreased. The effect of ageing on the hardness of El21-AlN composites was found to be much less than this effect on the hardness of the host alloy. Electron backscatter diffraction (EBSD) analysis of El21 and El21-1%AlN after solution treatment confirm the random orientation of grains with a typical texture of random distribution. The as-cast creep results showed that the incorporation of nanoparticles could effectively improve the creep properties, while the results after solution treatment at 520 °C for 12 h followed by ageing treatment at 200 °C for 20 h confirmed that the minimum creep rate of T6-El21 was almost equal to the as-cast El21-AlN.

Impact of vacancy-solute clusters on the aging of α-Fe solid solutions

International Nuclear Information System (INIS)

Schuler, Thomas

2015-01-01

Understanding and monitoring the aging of steels under vacancy supersaturation is a challenge of great practical interest for many industrial groups, and most of all for those related to nuclear energy. These steels always contain interstitial solutes, either as alloying elements or as impurities, and vacancies (V) that are equilibrium structural defects of materials. We have chosen the Fe-V -X system (X = C, N or O) as a model system for ferritic steels. Vacancy-solute clusters are likely to form in such systems because, despite the very low concentrations of their components, these cluster show very high attractive bonding. First of all, we have been working on the computation of intrinsic equilibrium properties of individual clusters, both thermodynamic (free binding energies) and kinetic (mobilities, dissociation coefficients, and their relationship with continuum diffusion) properties. Thanks to this atomic-scale characterization procedure, we have been able to highlight various effects of these clusters on a macroscopic system containing different cluster types: increase of solute solubility limits and total vacancy concentrations, flux couplings between interstitial solutes and vacancies, acceleration of solute precipitation kinetics and precipitate dissolution by solid solution stabilization due to vacancies. These results would not have been obtained without the development and/or extension of analytical methods in statistical physics which are able to describe cluster's components and their interactions at the atomic scale. Finally, we have also been working on cavities in α-iron, the study of which requires a different approach. Our study highlights the impact of the atomic discrete lattice on the equilibrium shape of cavities, and describes various kinetic mechanisms of these objects at the atomic scale. (author) [fr

Precise scanning calorimeter for studying thermal properties of biological macromolecules in dilute solution.

Science.gov (United States)

Privalov, G; Kavina, V; Freire, E; Privalov, P L

1995-11-20

A precise scanning calorimeter for studying the heat capacity of liquids in a broad temperature range has been developed. By its design and capabilities this calorimeter is the first of a new generation for this type of instrument. This new scanning calorimeter operates differentially, is equipped with a pair of gold capillary cells and semiconductor sensors, and is able to scan up and down in temperature at user-selected rates. This instrument is completely operated by an integrated computer which also provides a full thermodynamic analysis of the results. Its construction does not involve the use of organic compounds, thus eliminating a source of baseline noise that has affected previous calorimeters. The operational temperature range of the instrument can be varied between 0 and 120 degrees C. The gold capillary cells (operational volume 0.8 ml) minimize temperature gradients in the heated/cooled liquid sample and permit easy washing and reloading without air bubbles. These features are crucial for the accuracy of difference heat capacity measurements and determination of the absolute value of the partial heat capacity of solute molecules. The measurements can be performed under an excess constant pressure (up to 3 atm) to prevent formation of gas bubbles and boiling of aqueous solutions above 100 degrees C. The noise level of the recorded heating/cooling power difference is below 50 x 10(-9) W (i.e., below 10 ncal/s) with a response half-time of 5 s. The reproducibility of the baseline without refilling the capillary cells is on the order of 0.5 x 10(-6) W. Reproducibility of the baseline upon refilling the cell is of the same order of magnitude. This provides an accuracy in difference heat capacity determination on the order of 10 mu cal/degrees Kml at a heating rate of 1 degree K/min.

Study of the sorption properties of the peat for removal of heavy metals

International Nuclear Information System (INIS)

Hayrapetyan, S.S.; Gevorgyan, S.A.; Hayrapetyan, L.S.; Bareghamyan, S.F.; Pirumyan, G.P.

2016-01-01

The processes of sorption of several heavy metals on peat samples taken from basin of lake Sevan (near Vardenis Gegharkunik region of Armenia) were investigated. The peat samples were taken from different locations from 1 m depth. The sorption processes have been done in the static mode. The peat samples were used without any modification, i.e. the sorption properties of natural raw peat were studied. The studies were conducted on the basis of synthetic solution containing ions of these following metals - Ni, Co, As, U, Ba. The sorption properties of peat were estimated by ICP-MS. Thus, peat can be a very effective sorption medium for removal of heavy metals from water. Most of them are absorbed in the first minutes of peat exposure to aqueous solution. For the sorption of barium, uranium, arsenic peat exhibits very high sorption efficiency. For comparison, their relative sorption values about 10 times more than those of cobalt, nickel and zinc.

An Exact Solution of the Binary Singular Problem

Directory of Open Access Journals (Sweden)

Baiqing Sun

2014-01-01

Full Text Available Singularity problem exists in various branches of applied mathematics. Such ordinary differential equations accompany singular coefficients. In this paper, by using the properties of reproducing kernel, the exact solution expressions of dual singular problem are given in the reproducing kernel space and studied, also for a class of singular problem. For the binary equation of singular points, I put it into the singular problem first, and then reuse some excellent properties which are applied to solve the method of solving differential equations for its exact solution expression of binary singular integral equation in reproducing kernel space, and then obtain its approximate solution through the evaluation of exact solutions. Numerical examples will show the effectiveness of this method.

Electronic, elastic, thermodynamic properties and structure disorder of γ-AlON solid solution from ab initio calculations

International Nuclear Information System (INIS)

Wang, Yuezhong; Lu, Tiecheng; Zhang, Rongshi; Jiang, Shengli; Qi, Jianqi; Wang, Ying; Chen, Qingyun; Miao, Naihua; He, Duanwei

2013-01-01

Highlights: ► We reassess the chemical bonding character of γ-AlON which shows strong ionicity. ► γ-AlON single-crystals exhibit highly elastic anisotropy. ► The thermodynamic properties are investigated in a wider temperature/pressure range. ► γ-AlON is an O/N partially disordered structure. - Abstract: Spinel aluminium oxynitride (γ-AlON), as a kind of transparent ceramic material expectable, is studied using the ab initio density functional method, in terms of electronic, elastic, thermodynamic properties and structure disorder. The results show that γ-AlON exhibits strong ionicity, as quantitatively expressed by (Al O 2.43+ ) 15 (Al T 2.41+ ) 8 (O 1.64- ) 27 (N 2.27- ) 5 from our reassessment of the ionic character. We summarize and speculate that the considered oxynitride single-crystals exhibit highly elastic anisotropy. The interpretation of the thermodynamic properties of γ-AlON according to quasi-harmonic Debye model confirm the available experiments and are extended to a wider temperature/pressure range. This material holds high elastic strength under extreme environments, where dB/dT absolute value is less than 0.03 GPa/K, independent of the pressure. Finally, we study the O/N structure disorder character of γ-AlON solid solution by investigating nine possible crystal structures. It is found that γ-AlON should be partially disordered, and in fact, the O/N ordering has a significant effect on the properties.

Differences in efficacy of two commercial 0.2% chlorhexidine mouthrinse solutions: a 4-day plaque re-growth study.

NARCIS (Netherlands)

Arweiler, N.B.; Boehnke, N.; Sculean, A.; Hellwig, E.; Auschill, T.M.

2006-01-01

BACKGROUND: The purpose of this clinical cross-over study was to examine the antibacterial and plaque-inhibiting properties of two chlorhexidine solutions compared with a negative control. MATERIAL AND METHODS: Twenty-one volunteers refrained from all oral hygiene measures, but rinsed instead twice

Study on structural and optical properties of α-(AlxCr1-x)2O3 (0 ≤ x ≤ 1) solid solutions

Science.gov (United States)

Jangir, Ravindra; Kumar, Dharmendra; Srihari, Velaga; Ganguli, Tapas

2018-04-01

We report on structural and optical properties for ternary α-(AlxCr1-x)2O3 (0 ≤ x ≤ 1) solid solutions synthesized by using solid sate reaction method. Single R-3c phase was obtained for the Aluminum composition of 0 ≤ x ≤ 1. Due to difference in the ionic radia of Al3+ and Cr3+, in plane lattice parameter showed deviation from the vegard's law. Optical absorption spectra for the solid solutions showed a blue shift of ˜ 0.5 eV in the optical gap. It has also been observed that Cr 3d level shifted towards the O 2p level in the valance band which indicates the enhancement of hybridization in the d and p levels, which is related to the delocalization of hole states, responsible for p-type conduction in wide band gap semiconductors. The results suggests that ternary α-(AlxCr1-x)2O3 (0 ≤ x ≤ 1) can be useful in the field of UV transparent electronics and UV photodetectors.

Solution-printed organic semiconductor blends exhibiting transport properties on par with single crystals

KAUST Repository

Niazi, Muhammad Rizwan; Li, Ruipeng; Li, Erqiang; Kirmani, Ahmad R.; Abdelsamie, Maged; Wang, Qingxiao; Pan, Wenyang; Payne, Marcia M.; Anthony, John E.; Smilgies, Detlef-M.; Thoroddsen, Sigurdur T; Giannelis, Emmanuel P.; Amassian, Aram

2015-01-01

Solution-printed organic semiconductors have emerged in recent years as promising contenders for roll-to-roll manufacturing of electronic and optoelectronic circuits. The stringent performance requirements for organic thin-film transistors (OTFTs) in terms of carrier mobility, switching speed, turn-on voltage and uniformity over large areas require performance currently achieved by organic single-crystal devices, but these suffer from scale-up challenges. Here we present a new method based on blade coating of a blend of conjugated small molecules and amorphous insulating polymers to produce OTFTs with consistently excellent performance characteristics (carrier mobility as high as 6.7 cm2 V−1 s−1, low threshold voltages of<1 V and low subthreshold swings <0.5 V dec−1). Our findings demonstrate that careful control over phase separation and crystallization can yield solution-printed polycrystalline organic semiconductor films with transport properties and other figures of merit on par with their single-crystal counterparts.

Solution-printed organic semiconductor blends exhibiting transport properties on par with single crystals

KAUST Repository

Niazi, Muhammad Rizwan

2015-11-23

Solution-printed organic semiconductors have emerged in recent years as promising contenders for roll-to-roll manufacturing of electronic and optoelectronic circuits. The stringent performance requirements for organic thin-film transistors (OTFTs) in terms of carrier mobility, switching speed, turn-on voltage and uniformity over large areas require performance currently achieved by organic single-crystal devices, but these suffer from scale-up challenges. Here we present a new method based on blade coating of a blend of conjugated small molecules and amorphous insulating polymers to produce OTFTs with consistently excellent performance characteristics (carrier mobility as high as 6.7 cm2 V−1 s−1, low threshold voltages of<1 V and low subthreshold swings <0.5 V dec−1). Our findings demonstrate that careful control over phase separation and crystallization can yield solution-printed polycrystalline organic semiconductor films with transport properties and other figures of merit on par with their single-crystal counterparts.

Optical and Piezoelectric Study of KNN Solid Solutions Co-Doped with La-Mn and Eu-Fe

Directory of Open Access Journals (Sweden)

Jesús-Alejandro Peña-Jiménez

2016-09-01

Full Text Available The solid-state method was used to synthesize single phase potassium-sodium niobate (KNN co-doped with the La3+–Mn4+ and Eu3+–Fe3+ ion pairs. Structural determination of all studied solid solutions was accomplished by XRD and Rietveld refinement method. Electron paramagnetic resonance (EPR studies were performed to determine the oxidation state of paramagnetic centers. Optical spectroscopy measurements, excitation, emission and decay lifetime were carried out for each solid solution. The present study reveals that doping KNN with La3+–Mn4+ and Eu3+–Fe3+ at concentrations of 0.5 mol % and 1 mol %, respectively, improves the ferroelectric and piezoelectric behavior and induce the generation of optical properties in the material for potential applications.

Environment-Friendly Post-Treatment of PEDOT-Tos Films by Aqueous Vitamin C Solutions for Tuning of Thermoelectric Properties

Science.gov (United States)

Khan, Ezaz Hasan; Thota, Sammaiah; Wang, Yiwen; Li, Lian; Wilusz, Eugene; Osgood, Richard; Kumar, Jayant

2018-04-01

Aqueous vitamin C solution has been used as an environment-friendly reducing agent for tuning the thermoelectric properties of p-toluenesulfonate-doped poly(3,4-ethylenedioxythiophene) (PEDOT-Tos) films. The de-doping of the PEDOT-Tos films by aqueous vitamin C solutions led to a decrease in the electrical conductivity of the films. The measured ultraviolet-visible-near-infrared and x-ray photoelectron spectra clearly indicated the reduction in the oxidation level from 37 to 23% when the PEDOT-Tos films were treated with 5% (w/v) aqueous vitamin C solutions. An increase in the Seebeck coefficient was measured, resulting in an increase in the figure-of-merit (ZT). A 42% increase in ZT was determined for the 5% aqueous vitamin C solution-treated PEDOT-Tos films with respect to that of the untreated films.

Effect of hydrocarbon chain length of aliphatic diluents on hydrodynamic properties of irradiated solutions of extractant

International Nuclear Information System (INIS)

Gumenyuk, V.E.; Pribush, A.G.; Egorov, G.F.

1990-01-01

To optimize the composition of n-paraffin mixtures with different molecular weight, used as a diluent (D) of extractant during extraction reprocessing of spent fuel, interrelation between D hydrocarbon chain length and change in hydrodynamic properties of extraction mixture on D basis depending on the dose has been considered. It is shown that the value of threshold dose loading (D crit ), at which a sharp change in hydrodynamic properties of tri-n-butyl phosphate solutions in D is observed, decreases with hydrocarbon chain length growth. Empiric ratio relating D crit value and the number of carbon atoms of D is obtained

A Comparative Study on Magnetostructural Properties of Barium Hexaferrite Powders Prepared by Polyethylene Glycol

OpenAIRE

Zehra Durmus

2014-01-01

Nanocrystalline particles of barium hexaferrite were synthesized by a sol-gel combustion route using nitrate-citrate gels prepared from metal nitrates and citric acid solutions with Fe/Ba molar ratio 12. The present paper aims to study the effect of addition of polyethylene glycol (PEG) solutions with different molecular weights (MW: 400, 2000, and 10.000 g/mol) on magnetostructural properties of barium hexaferrite. The formation of the barium hexaferrite was inspected using X-ray diffractio...

Surface and adsorptive properties of Moringa oleifera bark for removal of V(V) from aqueous solutions.

Science.gov (United States)

Mnisi, Robert Londi; Ndibewu, Peter Papoh

2017-11-04

The bark of Moringa oleifera, a cheap and readily available natural biopolymeric resource material, found to significantly reduce coliform load and turbidity in contaminated water is investigated in this paper. Its surface and adsorptive properties are investigated to explore its adsorptive potential in removing V(V) from aqueous solutions. Surface properties were investigated using FTIR, HRSEM/EDS, IC, and BET-N 2 adsorption techniques. Adsorptive properties were investigated by optimizing adsorption parameters such as pH, temperature, initial metal concentration, and adsorbent dosage, using V(V) as an adsorbate. The adsorption-desorption isotherms are typical of type II with a H3 hysteresis loop and is characteristic of a largely macroporous material. Bottle ink pores are observed, which can provide good accessibility of the active sites, even though the internal BET surface area is typically low (1.79 g/m 2 ). Solution pH significantly influences the adsorptive potential of the material. The low surface area negatively impacts on the adsorption capacity, but is compensated for by the exchangeable anions (Cl - , F - , PO 4 3- , NO 3 - , and SO 4 2- ) and cations (Ca 2+ , K + , Mg 2+ , and Al 3+ ) at the surface and the accessibility of the active sites. Adsorption isotherm modeling show that the surface is largely heterogeneous with complex multiple sites and adsorption is not limited to monolayer.

Studying the dynamics of colloidal particles with digital holographic microscopy and electromagnetic scattering solutions

Directory of Open Access Journals (Sweden)

V. N. Manoharan

2011-09-01

Full Text Available Digital holographic microscopy (DHM can measure the 3D positions as well as the scattering properties of colloidal particles in a single 2D image. We describe DHM and our analysis of recorded holograms with exact scattering solutions, which permit the measurement of 3D particle positions with ∼10 nm precision and millisecond time resolution, and discuss studies of the Brownian dynamics of clusters of spheres with DHM.

Pole solutions for flame front propagation

CERN Document Server

Kupervasser, Oleg

2015-01-01

This book deals with solving mathematically the unsteady flame propagation equations. New original mathematical methods for solving complex non-linear equations and investigating their properties are presented. Pole solutions for flame front propagation are developed. Premixed flames and filtration combustion have remarkable properties: the complex nonlinear integro-differential equations for these problems have exact analytical solutions described by the motion of poles in a complex plane. Instead of complex equations, a finite set of ordinary differential equations is applied. These solutions help to investigate analytically and numerically properties of the flame front propagation equations.

Structural analysis and magnetic properties of solid solutions of Co–Cr system obtained by mechanical alloying

Energy Technology Data Exchange (ETDEWEB)

Betancourt-Cantera, J.A. [Área Académica de Ciencias de la Tierra y Materiales, UAEH Carr., Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Sánchez-De Jesús, F., E-mail: fsanchez@uaeh.edu.mx [Área Académica de Ciencias de la Tierra y Materiales, UAEH Carr., Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Bolarín-Miró, A.M. [Área Académica de Ciencias de la Tierra y Materiales, UAEH Carr., Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Betancourt, I.; Torres-Villaseñor, G. [Departamento de Materiales Metálicos y Cerámicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, México D.F. 04510 (Mexico)

2014-03-15

In this paper, a systematic study on the structural and magnetic properties of Co{sub 100−x}Cr{sub x} alloys (0solutions based on Co-hcp, Co-fcc and Cr-bcc structures were obtained. The saturation polarization indicated a maximum value of 1.17 T (144 Am{sup 2}/kg) for the Co{sub 90}Cr{sub 10}, which decreases with the increasing of the Cr content up to x=80, as a consequence of the dilution effect of the magnetic moment which is caused by the Cr content and by the competition between ferromagnetic and antiferromagnetic exchange interactions. The coercivity increases up to 34 kA/m (435 Oe) for Co{sub 40}Cr{sub 60}. For Cr rich compositions, it is observed an important decrease reaching 21 kA/m (272 Oe) for Co{sub 10}Cr{sub 90,} it is related to the grain size and the structural change. Besides, the magnetic anisotropy constant was determined for each composition. Magnetic thermogravimetric analysis allowed to obtain Curie temperatures corresponding to the formation of hcp-Co(Cr) and fcc-Co(Cr) solid solutions. - Highlights: • Mechanical alloying (MA) induces the formation of solid solutions of Co–Cr system in non-equilibrium. • We report the crystal structure and the magnetic behavior of Co–Cr alloys produced by MA. • MA improves the magnetic properties of Co–Cr system.

Interactions between Surfactants in Solution and Electrospun Protein Fibers: Effects on Release Behavior and Fiber Properties

DEFF Research Database (Denmark)

Boutrup Stephansen, Karen; García-Díaz, María; Jessen, Flemming

2016-01-01

, and drug delivery. In the present study, we present a systematic investigation of how surfactants and proteins, as physiologically relevant components, interact with insulin-loaded fish sarcoplasmic protein (FSP) electrospun fibers (FSP-Ins fibers) in solution and thereby affect fiber properties...... such as accessible surface hydrophilicity, physical stability, and release characteristics of an encapsulated drug. Interactions between insulin-loaded protein fibers and five anionic surfactants (sodium taurocholate, sodium taurodeoxycholate, sodium glycocholate, sodium glycodeoxycholate, and sodium dodecyl sulfate......Intermolecular interaction phenomena occurring between endogenous compounds, such as proteins and bile salts, and electrospun compounds are so far unreported, despite the exposure of fibers to such biorelevant compounds when applied for biomedical purposes, e.g., tissue engineering, wound healing...

Effect of the hydrophilic block length on the surface-active and micellar thermodynamic properties of oxyethylene-oxybutylene diblock copolymers in aqueous solution

International Nuclear Information System (INIS)

Khan, A.; Usman, M.; Siddiq, M.; Fatima, G.; Harrison, W.

2009-01-01

The effect of hydrophilic block length on the surface and micellar thermodynamic properties of aqueous solution of E/sub 40/B/sub 8/, E/sub 80/B/sub 8/ and E/sub 120/B/sub 8/ diblock copolymers, were studied by surface tension measurements over a wide concentration and temperature range; where E stands for an oxyethylene unit and B for an oxybutylene unit. Like conventional surfactants, two breaks (change in the slope) were observed in the surface tension vs logarithm of concentration curve for all the three copolymers. Surface tension measurements were used to estimate surface excess concentrations (r m), area per molecule at air/water interface a and thermodynamic parameters for all adsorption of the pre-micellar region in the temperature range 20 to 50 degree C. Likewise the critical micelle concentration, CMC and thermodynamic parameters for micellization were also calculated for the post-micellar solutions at all temperatures. For comparison the thermodynamic parameters of adsorption and micellization are discussed in detail. The impact of varying E-block length and temperature on all calculated parameters are also discussed. This study shows the importance of hydrophobic-hydrophilic-balance (HHB) of copolymers on various surface and micellar properties. (author)

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.

Application of Solution NMR Spectroscopy to Study Protein Dynamics

Directory of Open Access Journals (Sweden)

Christoph Göbl

2012-03-01

Full Text Available Recent advances in spectroscopic methods allow the identification of minute fluctuations in a protein structure. These dynamic properties have been identified as keys to some biological processes. The consequences of this structural flexibility can be far‑reaching and they add a new dimension to the structure-function relationship of biomolecules. Nuclear Magnetic Resonance (NMR spectroscopy allows the study of structure as well as dynamics of biomolecules in a very broad range of timescales at atomic level. A number of new NMR methods have been developed recently to allow the measurements of time scales and spatial fluctuations, which in turn provide the thermodynamics associated with the biological processes. Since NMR parameters reflect ensemble measurements, structural ensemble approaches in analyzing NMR data have also been developed. These new methods in some instances can even highlight previously hidden conformational features of the biomolecules. In this review we describe several solution NMR methods to study protein dynamics and discuss their impact on important biological processes.

Thermoluminescence properties of zinc oxide obtained by solution combustion synthesis

Energy Technology Data Exchange (ETDEWEB)

Orante B, V. R.; Escobar O, F. M.; Cruz V, C. [Universidad de Sonora, Departamento de Investigacion en Polimeros y Materiales, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Bernal, R., E-mail: victor.orante@polimeros.uson.mx [Universidad de Sonora, Departamento de Investigacion en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico)

2014-08-15

High-dose thermoluminescence dosimetry properties of novel zinc oxide obtained by solution combustion synthesis in a glycine-nitrate process, with a non-stoichiometric value of the elemental stoichiometric coefficient (Φ{sub c}) are presented in this work. Zn O powder samples obtained were annealed afterwards at 900 grades C during 2 h in air. Sintered particles of sizes between ∼ 0.5 and ∼ 2 μm were obtained, according to scanning electron microscopy results. X-ray diffraction indicates the presence of the hexagonal phase of Zn O for the powder samples obtained, before and after thermal annealing, without any remaining nitrate peaks observed. Thermoluminescence glow curves of Zn O obtained after being exposed to beta radiation consists of two maxima; one located at ∼ 149 grades C and another at ∼ 308 grades C, being the latter the dosimetric component of the curve. Dosimetric characterization of non-stoichiometric zinc oxide provided experimental evidence like asymptotic behavior of the Tl signal fading for times greater than 16 h between irradiation and the corresponding Tl readout, as well as the linear behaviour of the dose response without saturation in the dose interval studied (from 12.5 up to 400 Gy). Such characteristics place Zn O phosphors obtained in this work as a promising material for high-dose radiation dosimetry applications (e.g., radiotherapy and food industry). (author)

Thermoluminescence properties of zinc oxide obtained by solution combustion synthesis

International Nuclear Information System (INIS)

Orante B, V. R.; Escobar O, F. M.; Cruz V, C.; Bernal, R.

2014-08-01

High-dose thermoluminescence dosimetry properties of novel zinc oxide obtained by solution combustion synthesis in a glycine-nitrate process, with a non-stoichiometric value of the elemental stoichiometric coefficient (Φ c ) are presented in this work. Zn O powder samples obtained were annealed afterwards at 900 grades C during 2 h in air. Sintered particles of sizes between ∼ 0.5 and ∼ 2 μm were obtained, according to scanning electron microscopy results. X-ray diffraction indicates the presence of the hexagonal phase of Zn O for the powder samples obtained, before and after thermal annealing, without any remaining nitrate peaks observed. Thermoluminescence glow curves of Zn O obtained after being exposed to beta radiation consists of two maxima; one located at ∼ 149 grades C and another at ∼ 308 grades C, being the latter the dosimetric component of the curve. Dosimetric characterization of non-stoichiometric zinc oxide provided experimental evidence like asymptotic behavior of the Tl signal fading for times greater than 16 h between irradiation and the corresponding Tl readout, as well as the linear behaviour of the dose response without saturation in the dose interval studied (from 12.5 up to 400 Gy). Such characteristics place Zn O phosphors obtained in this work as a promising material for high-dose radiation dosimetry applications (e.g., radiotherapy and food industry). (author)

Exact interior solutions in 2 + 1-dimensional spacetime

Energy Technology Data Exchange (ETDEWEB)

Rahaman, Farook; Bhar, Piyali [Jadavpur University, Department of Mathematics, Kolkata, West Bengal (India); Biswas, Ritabrata [Indian Institute of Engineering Sceince and Technology Shibpur, Howrah, West Bengal (India); Usmani, A.A. [Aligarh Muslim University, Department of Physics, Aligarh, Uttar Pradesh (India)

2014-04-15

We provide a new class of exact solutions for the interior in 2 + 1-dimensional spacetime. The solutions obtained for the perfect fluid model both with and without cosmological constant (Λ) are found to be regular and singularity free. It assumes very simple analytical forms that help us to study the various physical properties of the configuration. Solutions without Λ are found to be physically acceptable. (orig.)

Localized solutions for a nonlocal discrete NLS equation

International Nuclear Information System (INIS)

Ben, Roberto I.; Cisneros Ake, Luís; Minzoni, A.A.; Panayotaros, Panayotis

2015-01-01

We study spatially localized time-periodic solutions of breather type for a cubic discrete NLS equation with a nonlocal nonlinearity that models light propagation in a liquid crystal waveguide array. We show the existence of breather solutions in the limit where both linear and nonlinear intersite couplings vanish, and in the limit where the linear coupling vanishes with arbitrary nonlinear intersite coupling. Breathers of this nonlocal regime exhibit some interesting features that depart from what is seen in the NLS breathers with power nonlinearity. One property we see theoretically is the presence of higher amplitude at interfaces between sites with zero and nonzero amplitude in the vanishing linear coupling limit. A numerical study also suggests the presence of internal modes of orbitally stable localized modes. - Highlights: • Show existence of spatially localized solutions in nonlocal discrete NLS model. • Study spatial properties of localized solutions for arbitrary nonlinear nonlocal coupling. • Present numerical evidence that nonlocality leads to internal modes around stable breathers. • Present theoretical and numerical evidence for amplitude maxima at interfaces

Localized solutions for a nonlocal discrete NLS equation

Energy Technology Data Exchange (ETDEWEB)

Ben, Roberto I. [Instituto de Desarrollo Humano, Universidad Nacional de General Sarmiento, J.M. Gutiérrez 1150, 1613 Los Polvorines (Argentina); Cisneros Ake, Luís [Department of Mathematics, ESFM, Instituto Politécnico Nacional, Unidad Profesional Adolfo López Mateos Edificio 9, 07738 México D.F. (Mexico); Minzoni, A.A. [Depto. Matemáticas y Mecánica, I.I.M.A.S.-U.N.A.M., Apdo. Postal 20-726, 01000 México D.F. (Mexico); Panayotaros, Panayotis, E-mail: panos@mym.iimas.unam.mx [Depto. Matemáticas y Mecánica, I.I.M.A.S.-U.N.A.M., Apdo. Postal 20-726, 01000 México D.F. (Mexico)

2015-09-04

We study spatially localized time-periodic solutions of breather type for a cubic discrete NLS equation with a nonlocal nonlinearity that models light propagation in a liquid crystal waveguide array. We show the existence of breather solutions in the limit where both linear and nonlinear intersite couplings vanish, and in the limit where the linear coupling vanishes with arbitrary nonlinear intersite coupling. Breathers of this nonlocal regime exhibit some interesting features that depart from what is seen in the NLS breathers with power nonlinearity. One property we see theoretically is the presence of higher amplitude at interfaces between sites with zero and nonzero amplitude in the vanishing linear coupling limit. A numerical study also suggests the presence of internal modes of orbitally stable localized modes. - Highlights: • Show existence of spatially localized solutions in nonlocal discrete NLS model. • Study spatial properties of localized solutions for arbitrary nonlinear nonlocal coupling. • Present numerical evidence that nonlocality leads to internal modes around stable breathers. • Present theoretical and numerical evidence for amplitude maxima at interfaces.

Microspectroscopic imaging of solution plasma: How do its physical properties and chemical species evolve in atmospheric-pressure water vapor bubbles?

Science.gov (United States)

Yui, Hiroharu; Banno, Motohiro

2018-01-01

In this article, we review the development of scientific instruments for obtaining information on the evolution of physical properties and chemical species of solution plasma (SP). When a pulsed high voltage is applied between electrodes immersed in an aqueous solution, SP is formed in water vapor bubbles transiently generated in the solution under atmospheric pressure. To clarify how SP emerges in water vapor bubbles and is sustained in solutions, an instrument with micrometer spatial resolution and nanosecond temporal resolution is required. To meet these requirements, a microscopic system with a custom-made optical discharge cell was newly developed, where the working distance between the SP and the microscopic objective lens was minimized. A hollow electrode equipped in the discharge cell also enabled us to control the chemical composition in water vapor bubbles. To study the spatial and temporal evolutions of chemical species in micrometer and nano- to microsecond regions, a streak camera with a spectrometer and a CCD detector with a time-gated electronic device were combined with the microscope system. The developed instrument is expected to contribute to providing a new means of developing new schemes for chemical reactions and material syntheses.

Improvement of operational properties of shell limestone building materials by polysulfide solution impregnation

Directory of Open Access Journals (Sweden)

MASSALIMOV Ismail Alexandrovich

2017-06-01

Full Text Available The data of studies on the effectiveness of impregnation with polysulfide solutions of shell limestone used as facing and wall material, as well as for the manufacture of road products are presented. Modification of the limestone with the impregnating composition «Akvastat» created by the authors which is sulfur-containing water-based solution of calcium polysulfide containing alcohols and surfactants, can significantly reduce water absorption and increase durability of limestone. Impregnating composition on the basis of calcium polysulfide possesses density of 1.22–1.24 g/cm3, the infiltrant penetrates into the pore structure of limestone to a depth of 4 cm or more, depending on the density and structure of the sample. While the material is drying, sulfur nanoparticles are crystallized from the polysulfide solution in its pores. They partially fill pore space and form protective durable insoluble hydrophobic coating that impedes the penetration of water into the pores of the limestone, but preserves its vapor permeability, which is important for wall and decoration materials. The evaluation of protective coatings was performed with laser particle size analyzer, scanning probe microscope and a diffractometer. It showed that the average size of the particles forming the protective coating is in the range of 20–25 nm, the particles shape is spherical, the particles are elemental sulfur with orthorhombic structure of the crystal lattice. The processing of shell limestone with calcium polysulphide solution provides formation of coating based on nanosized sulfur on the surface of stone pores. The coating partially fills the pore space and, as it is hydrophobic, reduces the water absorption of the samples by a factor of 5–8, increases their average density by 22–27%, strength in 1,2–1,3 times, the softening factor by 6–19%, that makes possible to predict the increase of the durability of building materials based on shell limestone to 1

Study of liquids and solutions

International Nuclear Information System (INIS)

Bellissent-Funel, M.C.

1994-01-01

A critical review of what has been achieved on the structure of liquids and solutions and the capabilities and developments of neutron scattering in this domain, are presented. A great variety of simple to complex systems has been investigated with the aim of obtaining a full microscopic description of the structure. Selected examples demonstrate the neutron scattering determination of interaction potentials, intermolecular structures and partial structure factors of complex systems. The isotopic substitution method is illustrated by the application to the study of the solvation of ions in aqueous and non aqueous solutions. (author). 9 figs., 32 refs

Electronic, elastic, thermodynamic properties and structure disorder of {gamma}-AlON solid solution from ab initio calculations

Energy Technology Data Exchange (ETDEWEB)

Wang, Yuezhong, E-mail: wyzphysics@163.com [Department of Physics and Key Laboratory for Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Tianjin Jinhang Institute of Technical Physics, Tianjin 300192 (China); Lu, Tiecheng, E-mail: lutiecheng@scu.edu.cn [Department of Physics and Key Laboratory for Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); International Center for Material Physics, Chinese Academy of Sciences, Shenyang 110015 (China); Zhang, Rongshi [Tianjin Jinhang Institute of Technical Physics, Tianjin 300192 (China); Jiang, Shengli; Qi, Jianqi; Wang, Ying [Department of Physics and Key Laboratory for Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Chen, Qingyun [Department of Physics and Key Laboratory for Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); National Defense Key Discipline Laboratory of Nuclear Waste and Environmental Safety, Southwest University of Science and Technology, Mianyang 621010 (China); Miao, Naihua [Physique Theorique des Materiaux, Universite de Liege, Sart Tilman B-4000 (Belgium); He, Duanwei [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610064 (China)

2013-01-25

Highlights: Black-Right-Pointing-Pointer We reassess the chemical bonding character of {gamma}-AlON which shows strong ionicity. Black-Right-Pointing-Pointer {gamma}-AlON single-crystals exhibit highly elastic anisotropy. Black-Right-Pointing-Pointer The thermodynamic properties are investigated in a wider temperature/pressure range. Black-Right-Pointing-Pointer {gamma}-AlON is an O/N partially disordered structure. - Abstract: Spinel aluminium oxynitride ({gamma}-AlON), as a kind of transparent ceramic material expectable, is studied using the ab initio density functional method, in terms of electronic, elastic, thermodynamic properties and structure disorder. The results show that {gamma}-AlON exhibits strong ionicity, as quantitatively expressed by (Al{sub O}{sup 2.43+}){sub 15}(Al{sub T}{sup 2.41+}){sub 8}(O{sup 1.64-}){sub 27}(N{sup 2.27-}){sub 5} from our reassessment of the ionic character. We summarize and speculate that the considered oxynitride single-crystals exhibit highly elastic anisotropy. The interpretation of the thermodynamic properties of {gamma}-AlON according to quasi-harmonic Debye model confirm the available experiments and are extended to a wider temperature/pressure range. This material holds high elastic strength under extreme environments, where dB/dT absolute value is less than 0.03 GPa/K, independent of the pressure. Finally, we study the O/N structure disorder character of {gamma}-AlON solid solution by investigating nine possible crystal structures. It is found that {gamma}-AlON should be partially disordered, and in fact, the O/N ordering has a significant effect on the properties.

Conformations and solution properties of star-branched polyelectrolytes

NARCIS (Netherlands)

Borisov, O.V.; Zhulina, E.B.; Leermakers, F.A.M.; Ballauff, M.; Muller, A.H.E.

2011-01-01

Aqueous solutions of star-like polyelectrolytes (PEs) exhibit distinctive features that originate from the topological complexity of branched macromolecules. In a salt-free solution of branched PEs, mobile counterions preferentially localize in the intramolecular volume of branched macroions.

Study of Bovine Serum Albumin Solubility in Aqueous Solutions by Intrinsic Viscosity Measurements

Directory of Open Access Journals (Sweden)

Martin Alberto Masuelli

2013-01-01

Full Text Available The behavior of bovine serum albumin (BSA in water is scarcely studied, and the thermodynamic properties arising from the experimental measurements have not been reported. Intrinsic viscosity measurements are very useful in assessing the interaction between the solute and solvent. This work discussed in a simple determination of the enthalpy of BSA in aqueous solution when the concentration ranges from 0.2 to 36.71% wt. and the temperature from 35 to 40°C. The relationship between the concentration and intrinsic viscosity is determined according to the method of Huggins. The temperature increase reduces the ratio between inherent viscosity and concentration (ηi/c. This is reflected in the Van't Hoff curve. Furthermore, this work proposes hydrodynamic cohesion value as an indicator of the degree of affinity of protein with water and thermodynamic implications in conformational changes.

Nonelectrolyte NRTL-NRF model to study thermodynamics of strong and weak electrolyte solutions

Energy Technology Data Exchange (ETDEWEB)

Haghtalab, Ali, E-mail: haghtala@modares.ac.i [Department of Chemical Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Shojaeian, Abolfazl; Mazloumi, Seyed Hossein [Department of Chemical Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of)

2011-03-15

An electrolyte activity coefficient model is proposed by combining non-electrolyte NRTL-NRF local composition model and Pitzer-Debye-Hueckel equation as short-range and long-range contributions, respectively. With two adjustable parameters per each electrolyte, the present model is applied to correlation of the mean activity coefficients of more than 150 strong aqueous electrolyte solutions at 298.15 K. Also the results of the present model are compared with the other local composition models such as electrolyte-NRTL, electrolyte-NRTL-NRF and electrolyte-Wilson-NRF models. Moreover, the present model is used for prediction of the osmotic coefficient of several aqueous binary electrolytes systems at 298.15 K. Also the present activity coefficient model is adopted for representation of nonideality of the acid gases, as weak gas electrolytes, soluble in alkanolamine solutions. The model is applied for calculation of solubility and heat of absorption (enthalpy of solution) of acid gas in the two {l_brace}(H{sub 2}O + MDEA + CO{sub 2}) and (H{sub 2}O + MDEA + H{sub 2}S){r_brace} systems at different conditions. The results demonstrate that the present model can be successfully applied to study thermodynamic properties of both strong and weak electrolyte solutions.

MWCNTs/Cellulose Hydrogels Prepared from NaOH/Urea Aqueous Solution with Improved Mechanical Properties

Directory of Open Access Journals (Sweden)

Yingpu Zhang

2015-01-01

Full Text Available Novel high strength composite hydrogels were designed and synthesized by introducing multiwalled carbon nanotubes (MWCNTs into cellulose/NaOH/urea aqueous solution and then cross-linked by epichlorohydrin. MWCNTs were used to modify the matrix of cellulose. The structure and morphology of the hydrogels were characterized by Fourier transform infrared (FT-IR spectroscopy, high resolution transmission electron microscopy (HR-TEM, and scanning electron microscopy (SEM. The results from swelling testing revealed that the equilibrium swelling ratio of hydrogels decreased with the increment of MWCNTs content. Thermogravimetric analysis (TGA and dynamic mechanical analysis (DMA results demonstrated that the introduction of MWCNT into cellulose hydrogel networks remarkably improved both thermal and mechanical properties of the composite hydrogels. The preparation of MWCNTs modifiedcellulose-based composites with improved mechanical properties was the first important step towards the development of advanced functional materials.

Metric solution of a spinning mass

International Nuclear Information System (INIS)

Sato, H.

1982-01-01

Studies on a particular class of asymptotically flat and stationary metric solutions called the Kerr-Tomimatsu-Sato class are reviewed about its derivation and properties. For a further study, an almost complete list of the papers worked on the Tomimatsu-Sato metrics is given. (Auth.)

Study on time of flight property of electron optical systems by differential algebraic method

International Nuclear Information System (INIS)

Cheng Min; Tang Tiantong; Yao Zhenhua

2002-01-01

Differential algebraic method is a powerful and promising technique in computer numerical analysis. When applied to nonlinear dynamics systems, the arbitrary high-order transfer properties of the systems can be computed directly with high precision. In this paper, the principle of differential algebra is applied to study on the time of flight (TOF) property of electron optical systems and their arbitrary order TOF transfer properties can be numerically calculated out. As an example, TOF transfer properties of a uniform magnetic sector field analyzer have been studied by differential algebraic method. Relative errors of the first-order and second-order TOF transfer coefficients of the magnetic sector field analyzer are of the order 10 -11 or smaller compared with the analytic solutions. It is proved that differential algebraic TOF method is of high accuracy and very helpful for high-order TOF transfer property analysis of electron optical systems. (author)

Investigation of the main chemical properties of water-magnesium chloride solutions. Application to the understanding of stress corrosion phenomena in 17.12 Mo stainless steel

International Nuclear Information System (INIS)

Hasni, Abdellatif

1988-01-01

This research thesis reports the investigation of the main chemical properties of concentrated aqueous solutions of MgCl 2 and of their influence of stress corrosion of 17Cr-12Ni-2Mo stainless steel. It shows that the most important chemical properties are the equilibrium pH and the acidity range of MgCl 2 aqueous solutions, and that they strongly depend on solution temperature and concentration. The medium pH is governed by the increased acidity of water in presence of Mg ++ ions, while the acidity range is determined by a hydrolysis reaction of these ions which results in a precipitation of magnesium hydroxyl-chlorides. The investigation of stress corrosion behaviour of the steel in MgCl 2 solutions with varying temperature and concentration shows that this behaviour comes down to a prevailing pH effect which results from the variation of these both parameters, with a not negligible but less important effect of temperature. A study of cracking surfaces indicates that it is possible to pass from a transgranular to an intergranular mode by a variation of either media aggressiveness (pH, temperature, voltage) or strain rate. These results are explained by a concept of kinetic factor which limits stress corrosion [fr

Erbium(III) in aqueous solution: an ab initio molecular dynamics study.

Science.gov (United States)

Canaval, Lorenz R; Sakwarathorn, Theerathad; Rode, Bernd M; Messner, Christoph B; Lutz, Oliver M D; Bonn, Günther K

2013-12-05

Structural and dynamical properties of the erbium(III) ion in water have been obtained by means of ab initio quantum mechanical charge field molecular dynamics (QMCF-MD) simulations for the ground state and an excited state. The quality of the simulations has been monitored by recording UV/vis and Raman spectra of dilute solutions of ErCl3 and Er(NO3)3 in water and by comparison with EXAFS data from literature. Slight deviations between these data can be mainly attributed to relativistic effects, which are not sufficiently considered by the methodological framework. In both simulations, a mixture of coordination numbers eight and nine and a ligand exchange on the picosecond range are observed. The strength of the Er-ligand bond is considerably lower than that of trivalent transition metal ions but higher than that for La(III) and Ce(III) in aqueous solution. The main difference between ground state and excited state is the ligand exchange rate of the first shell. The second hydration shell is stable in both cases but with significantly different properties.

Physicochemical properties of binary solutions of propylene carbonate-acetonitrile in the range of 253.15-313.15 K

Science.gov (United States)

Tyunina, E. Yu.; Chekunova, M. D.

2017-05-01

The density, dynamic viscosity, and dielectric constant of propylene carbonate solutions with acetonitrile are measured over the composition of a mixed solvent at temperatures of 253.15, 273.15, 293.15, and 313.15 K. The molar volume, molar viscosity, and molar capacity of a mixture of propylene carbonate-acetonitrile and an excess amount of it are calculated. The effect the temperature and composition of the mixture have on the excess molar properties is discussed. A linear correlation is observed between the values of the molar fluidity, capacity, polarization, and molar volume of the studied system.

Physical Properties and Thermal Decomposition of Aqueous Solutions of 2-Amino-2-hydroxymethyl-1, 3-propanediol (AHPD)

Science.gov (United States)

Murshid, Ghulam; Shariff, Azmi Mohd; Lau, K. K.; Bustam, Mohammad Azmi; Ahmad, Faizan

2011-10-01

Physical properties such as density, viscosity, refractive index, surface tension, and thermal stability of 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD) were experimentally measured. All the experimental measurements were made over a wide range of temperatures from (298.15 to 333.15) K and AHPD concentrations of (1, 7, 13, 19, and 25) mass%. An overall decrease in all the measured physical properties was observed with increasing temperature. The experimental results are presented as a function of temperature and AHPD mass fraction. All the measured physical properties were correlated as a function of temperature. Thermal decomposition of pure and aqueous solutions of AHPD was investigated using a thermo-gravimetric analyzer (TGA) at a heating rate of 10 K · min-1.

Classical and Weak Solutions for Two Models in Mathematical Finance

Science.gov (United States)

Gyulov, Tihomir B.; Valkov, Radoslav L.

2011-12-01

We study two mathematical models, arising in financial mathematics. These models are one-dimensional analogues of the famous Black-Scholes equation on finite interval. The main difficulty is the degeneration at the both ends of the space interval. First, classical solutions are studied. Positivity and convexity properties of the solutions are discussed. Variational formulation in weighted Sobolev spaces is introduced and existence and uniqueness of the weak solution is proved. Maximum principle for weak solution is discussed.

Solute redistribution studies in oxidised zirconium alloys

Energy Technology Data Exchange (ETDEWEB)

Khera, S K; Kale, G B; Gadiyar, H S [Bhabha Atomic Research Centre, Bombay (India). Metallurgy Div.

1977-01-01

Electron microprobe studies on solute distribution in oxide layers and in the regions near oxide metal interface have been carried out in the case of zircaloy-2 and zirconium binary alloys containing niobium, tin, iron, copper, chromium and nickel and oxidised in steam at 550 deg C. In the case of alloys having higher oxidation rates, the oxide of solute element was found to dissolve in ZrO/sub 2/ without any composition variation. However, for solute addition with limited solubility like Cr, Cu and Fe, solute enrichment at metal/oxide interface and depletion of the same matrix has been observed. The intensity profiles for nickel distribution were also found to be identical to Fe or Cr distribution. The mode of solute distribution has been discussed in relation to oxidation behaviour of these alloys.

Statistical mechanics of protein solutions

NARCIS (Netherlands)

Prinsen, P.

2007-01-01

We study theoretically thermodynamic properties of spherical globular proteins in aqueous solution with added monovalent salt. We show how one can determine an effective interaction potential between the proteins from experimental data as a function of salt concentration and we apply this to the

Diffusion, swelling, cross linkage study and mechanical properties of ZnO doped PVA/NaAlg blend polymer nanocomposite

Science.gov (United States)

Guruswamy, B.; Ravindrachary, V.; Shruthi, C.; Hegde, Shreedatta; Sagar, Rohan N.

2018-04-01

ZnO nano particles were synthesized using a chemical precipitation method. Pure and ZnO nano particle doped PVA-NaAlg blend composite films were prepared using solution casing method. Structural information of these composites was studied using FTIR. Diffusion kinetics of these polymer blend composite were studied using Flory-Huggins theory. Using these diffusion studies, cross-linking density and swelling properties of the films were analyzed. Mechanical properties of these composite are also studied.

Effect of Solution Properties on Arsenic Adsorption by Drinking Water Treatment Residuals

Science.gov (United States)

Nagar, R.; Sarkar, D.; Datta, R.; Sharma, S.

2005-05-01

purpose of the present study is to investigate the effect of solution properties, such as pH, ionic strength and competing ions on the adsorption of As by WTRs and WTR amended soils. Three types of WTRs are being used, namely Fe- WTR, Al- WTR and Ca-WTR. Effect of pH is being studied by varying the pH values between 3 and 9. The solid/solution ratio has been fixed at 1:5 and a 24 h equilibration has been chosen based on the results of earlier adsorption experiments. Furthermore, As adsorption will be studied in presence of potentially competing ions such as phosphate, sulfate, and selenate. Keywords: Adsorption, water treatment residuals, oxyanions, in-situ remediation, Arsenic

CONDENSED MATTER: STRUCTURE, MECHANICAL AND THERMAL PROPERTIES: Molecular Dynamics Study of Stability of Solid Solutions and Amorphous Phase in the Cu-Al System

Science.gov (United States)

Yang, Bin; Lai, Wen-Sheng

2009-06-01

The relative stability of fcc and bcc solid solutions and amorphous phase with different compositions in the Cu-Al system is studied by molecular dynamics simulations with n-body potentials. For Cu1-xAlx alloys, the calculations show that the fcc solid solution has the lowest energies in the composition region with x 0.72, while the bee solid solution has the lowest energies in the central composition range, in agreement with the ball-milling experiments that a single bcc solid solution with 0.30 < x < 0.70 is obtained. The evolution of structures in solid solutions and amorphous phase is studied by the coordination number (CN) and bond-length analysis so as to unveil the underlying physics. It is found that the energy sequence among three phases is determined by the competition in energy change originating from the bond length and CNs (or the number of bonds).

Influence of Monomer Concentration on the Morphologies and Electrochemical Properties of PEDOT, PANI, and PPy Prepared from Aqueous Solution

Directory of Open Access Journals (Sweden)

Shalini Kulandaivalu

2016-01-01

Full Text Available Poly(3,4-ethylenedioxyhiophene (PEDOT, polyaniline (PANI, and polypyrrole (PPy were prepared on indium tin oxide (ITO substrate via potentiostatic from aqueous solutions containing monomer and lithium perchlorate. The concentration of monomers was varied between 1 and 10 mM. The effects of monomer concentration on the polymers formation were investigated and compared by using Fourier transform infrared spectroscopy (FTIR, Raman spectroscopy, scanning electron microscopy (SEM, cyclic voltammetry (CV, and electrochemical impedance spectroscopy (EIS measurements. FTIR and Raman spectra showed no changes in the peaks upon the increment of the concentration. Based on the SEM images, the increment in monomer concentration gives significant effect on morphologies and eventually affects the electrochemical properties. PEDOT electrodeposited from 10 mM solution showed excellent electrochemical properties with the highest specific capacitance value of 12.8 mF/cm2.

Sol-gel reaction stability studied: Influence in the formation temperature and properties of ferroelectric thin films

International Nuclear Information System (INIS)

Perez, J.; Vilarinho, P.M.; Kholkin, A.L.; Almeida, A.

2009-01-01

Lead zirconium titanate (PZT) sol-gel solutions were prepared based on distilled lead acetate precursor solutions. A detailed analysis of the distillation effect on the lead precursor and the final PZT solution were carried out by Infrared and Raman techniques. It was found that the increase in the number of distillation steps experienced by the lead precursor solutions removes the constitutional water and increases the lead acetate-2-methoxyethanol interconnectivity; thus improving stability and avoiding the aging effect of the resulting PZT solutions. The thermal decomposition process of the PZT solutions was analyzed based on the thermogravimetric (TG) and differential thermogravimetric analysis (DTA) measurements. It was found that as the number of distillation steps in the lead precursor solutions increases, the decomposition rate increases and the formation temperature of pure perovskite PZT films decreases. X-ray diffraction (XRD) technique was used to study the film phase formation. A pure perovskite phase at 500 deg. C was found by the XRD analysis after the second distillation step. Scanning electron microscope technique was used to carry out the microstructural analysis. Dense microstructure was found in all analyzed films and an incipient columnar grain growth was revealed in PZT films prepared based on lead precursor solution with more than three distillation steps. The dependence of the dielectric, ferroelectric and piezoelectric properties on the number of distillation steps was revealed and a correlation between the distillation process, film microstructure properties and electrical performance was established

Preparation and characterization of novel PVDF nanofiltration membranes with hydrophilic property for filtration of dye aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Nikooe, Naeme, E-mail: naeme.nikooe@stu.um.ac.ir; Saljoughi, Ehsan, E-mail: saljoughi@um.ac.ir

2017-08-15

Highlights: • Preparation of novel PVDF nanofiltration membranes with noticeable hydrophilicity. • Simultaneous achievement of hydrophilicity and dye removal via addition of Brij-58. • In situ modification and stability of hydrophilic property via addition of Brij-58. - Abstract: In the present research, for the first time PVDF/Brij-58 blend nanofiltration membranes with remarkable performance in filtration of dye aqueous solution were prepared via immersion precipitation. A noticeable improvement in water permeation and fouling resistance of the PVDF membranes was achieved by using Brij-58 surfactant as a hydrophilic additive. Scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR) and water contact angle were applied for the investigation of membrane morphology, detection of the surface chemical composition and relative hydrophilicity/hydrophobicity, respectively. The membrane performance was studied and compared by determination of pure water flux (PWF) and filtration of synthetic reactive dye aqueous solutions as well as bovine serum albumin (BSA) as foulant model. It was found out that addition of 4 wt.% Brij-58 to the casting solution results in formation of membrane with remarkable hydrophilicity and fouling resistance (contact angle of 46° and flux recovery ratio (FRR) = 90%), higher porosity and consequently noticeable PWF (31.2 L/m{sup 2} h) and recognized dye rejection value (90%) in comparison with the pristine PVDF nanofiltration membrane. Addition of Brij-58 surfactant to the casting solution resulted in formation of NF membrane with higher hydrophilicity and permeability as well as higher dye rejection value in comparison with the addition of PEG 400 additive.

Synthesis and spectral properties of axially substituted zirconium(IV) and hafnium(IV) water soluble phthalocyanines in solutions

International Nuclear Information System (INIS)

Gerasymchuk, Y.S.; Volkov, S.V.; Chernii, V.Ya.; Tomachynski, L.A.; Radzki, St.

2004-01-01

Methods of synthesis of novel water soluble axially substituted Zr(IV) and Hf(IV) phthalocyanines with gallic, 5-sulfosalicyllic, oxalic acids, and methyl ester of gallic acid as axial ligands coordinated to the central atom metal of phthalocyanine are presented. The absorption spectra of complex solutions in various solvents were characterized. The dependence of the spectral red shift from Reichardt's empirical polarity parameter is described. The deviation from the linearity of Beer-Bouguer-Lambert law was investigated for the range of concentration 5x10 -6 to 10x10 -5 M. Fluorescent properties of axially substituted phthalocyaninato metal complexes in DMSO solutions were investigated

Hurlbert Index of Sexual Assertiveness: a study of psychometric properties in a Spanish sample.

Science.gov (United States)

Santos-Iglesias, Pablo; Sierra, Juan Carlos

2010-08-01

The study analyzed psychometric properties of a Spanish version of the Hurlbert Index of Sexual Assertiveness in a Spanish sample of 400 men and 453 women who had had a partner for the last 6 mo. or longer at the time of the study. Exploratory and confirmatory factor analyses suggested a two-factor solution with the factors Initiation and No shyness/Refusal. Internal consistency values for total scores were .87 and .83 for the factors, respectively. Convergent validity tests were also satisfactory. It is therefore reasonable to conclude that the Spanish version of the scale has appropriate psychometric properties.

Synthesis and Solution Properties of Zwitterionic Copolymer of Acrylamide with 3-[(2-Acrylamido)dimethylammonio]propanesulfonate

Energy Technology Data Exchange (ETDEWEB)

Xiao, Hui; Hu, Jing; Jin, Shuailin; Li, Rui Hai [Sichuan Univ., Chengdu (China)

2013-09-15

A novel zwitterionic monomer 3-[(2-acrylamido)dimethylammonio]propanesulfonate (DMADAS) was designed and synthesized in this study. Then it was polymerized with acrylamide (AM) by free radical polymerization in 0.5 mol/L NaCl solution with ammonium persulfate ((NH{sub 4}){sub 2}S{sub 2}O{sub 8}) and sodium sulfate (NaHSO{sub 3}) as initiator. The structure and composition of DMADAS and acrylamide-3-[(2-acrylamido)-dimethylammonio]propanesulfonate copolymer (P-AM-DMADAS) were characterized by FT-IR spectroscopy, {sup 1}H NMR and elemental analyses. Isoelectric point (IEP) of P-AM-DMADAS was tested by nanoparticle size and potential analyzer. Solution properties of copolymer were studied by reduced viscosity. Antipolyelectrolyte behavior was observed and was found to be enhanced with increasing DMADAS content in copolymer. The results showed that the viscosity of P-AM-DMADAS is 5.472 dl/g in pure water. Electrolyte was added, which weakened the mutual attraction between sulfonic acid group and quaternary ammonium group. The conformation became loose, which led to the increase of reduced viscosity. The ability of monovalent and divalent cation influencing the viscosity of zwitterionic copolymer obeyed the following sequence: Li{sup +} < Na{sup +} < K{sup +}, Mg{sup 2+} < Ca{sup 2+} < Ba{sup 2+}, and that of anion is in the order: Cl{sup -} < Br{sup -} < I{sup -}, CO{sub 3}{sup 2-} > SO{sub 3}{sup 2-} ≅ SO{sub 4}{sup 2-}.

Studies of solution-processed organic light-emitting diodes and their materials

Energy Technology Data Exchange (ETDEWEB)

Hellerich, Emily [Iowa State Univ., Ames, IA (United States)

2013-01-01

A hitherto unexplored approach is presented in which a small molecule is used as a host to polymer guests in solution-processed OLEDs. We find that the small molecule host results in much more efficient devices than the often-used alternative polymer host when used for the guests presented. It is likely that nano- and microstructural differences between the hosts contribute to the improvements, which highlights some interesting characteristics that can help to better understand the nature of these mixtures. A number of the guests used in this study were newly synthesized benzobisoxazole-based copolymers. New organic copolymers are presented that are based on the chemical structure of benzobisoxazoles, which have been shown in the past to have good electron transporting properties. The novel concept in this publication pertains to a change in the direction of polymerization, also known as the conjugation pathway, which we show increases the emission efficiency. This work highlights a unique and useful property of organic semiconducting materials in that they can be synthesized to create the desired characteristics. Earlier work is described that kick-started in our research group the use of small molecules in solution-processed OLEDs. Originally these devices were to be used in magnetoresistance studies, but the project took a different path when the devices were more efficient than expected. The efficient use of small molecules in solution-processed OLEDs is highlighted, which at the time was not often the case. Also, the important observation of the effect of solvent choice on the resultant film is emphasized, with discussion of the likely cause of these effects. Microcavity OLEDs are introduced in which the transparent anode ITO is replaced with semi-transparent thin silver, which creates an optical cavity within the devices. The goal was to expand a previous work that created an on-chip spectrometer covering wavelengths 493 to 639 nm. In this case, a spin

Solid solution barium–strontium chlorides with tunable ammonia desorption properties and superior storage capacity

DEFF Research Database (Denmark)

Bialy, Agata; Jensen, Peter Bjerre; Blanchard, Didier

2015-01-01

with spray drying and in situ thermogravimetric and structural characterization, we synthesize a range of new, stable barium-strontium chloride solid solutions with superior ammonia storage densities. By tuning the barium/strontium ratio, different crystallographic phases and compositions can be obtained...... with different ammonia ab- and desorption properties. In particular it is shown, that in the molar range of 35–50% barium and 65–50% strontium, stable materials can be produced with a practically usable ammonia density (both volumetric and gravimetric) that is higher than any of the pure metal halides...

Self-association of analgesics in aqueous solution: micellar properties of dextropropoxyphene hydrochloride and methadone hydrochloride.

Science.gov (United States)

Attwood, D; Tolley, J A

1980-08-01

The solution properties of several analgesics including dextropropoxyphene hydrochloride, methadone hydrochloride, dextromoramide acid tartrate and dipipanone hydrochloride have been examined using light scattering, conductivity, vapour pressure osmometry and surface tension techniques. A micellar pattern of association was established for dextropropoxyphene hydrochloride and methadone hydrochloride and critical micelle concentrations and aggregation numbers are reported. The hydrophobic contribution to the free energy of micellization of dextropropoxyphene was determined from measurement of the critical micelle concentration in the presence of added electrolyte.

Preparation and tribological properties of inclusion complex of β-cyclodextrin/dialkyl pentasulfide as additive in PEG-600 aqueous solution

International Nuclear Information System (INIS)

Guan, Jiju; Xu, Xuefeng; Li, Gan; Peng, Wei

2014-01-01

The inclusion complex of β-cyclodextrin (β-CD) and dialkyl pentasulfide (DPS), in which DPS was incorporated into β-CD cavities, was prepared by a co-precipitation method. The tribological properties of the complex used as lubricant additive in PEG 600 aqueous solution were investigated by a four-ball tester. The complex exhibited better tribological properties than β-CD under different loads, and also showed better anti-friction performance than DPS in the latter half of the test duration. The tribological action mechanism of the complex on a steel surface was studied according to the X-ray photoelectron spectroscopy (XPS) analyses. The β-CD molecules of the complexes were decomposed into various molecular fragments and the DPS molecules were released under the friction condition. It revealed that thiolate and ferrous sulfide (FeS) films formed by DPS played a major role, and iron alkoxide and carbon deposition films formed by the friction fragments of β-CD mainly exhibited anti-friction property on FeS-to-FeS interface. The interactions among different films led to the formation of a mixed boundary lubrication film.

Influence of solvent polarization and non-uniform ion size on electrostatic properties between charged surfaces in an electrolyte solution

Science.gov (United States)

Sin, Jun-Sik

2017-12-01

In this paper, we study electrostatic properties between two similar or oppositely charged surfaces immersed in an electrolyte solution by using the mean-field approach accounting for solvent polarization and non-uniform size effects. Applying a free energy formalism accounting for unequal ion sizes and orientational ordering of water dipoles, we derive coupled and self-consistent equations to calculate electrostatic properties between charged surfaces. Electrostatic properties for similarly charged surfaces depend on the counterion size but not on the coion size. Moreover, electrostatic potential and osmotic pressure between similarly charged surfaces are found to be increased with increasing counterion size. On the other hand, the corresponding ones between oppositely charged surfaces are related to both sizes of positive and negative ions. For oppositely charged surfaces, the electrostatic potential, number density of solvent molecules, and relative permittivity of an electrolyte having unequal ion sizes are not symmetric about the centerline between the charged surfaces. For either case, the consideration of solvent polarization results in a decrease in the electrostatic potential and the osmotic pressure compared to the case without the effect.

Investigating conceptual models for physical property couplings in solid solution models of cement

International Nuclear Information System (INIS)

Benbow, Steven; Watson, Claire; Savage, David

2005-11-01

The long-term behaviour of cementitious engineered barriers is an important process to consider when modelling the migration of radionuclides from a geological repository for nuclear waste. The modelling of cement is complicated by the fact that the cement is dominated by the behaviour of calcium silicate hydrate (CSH) gel which is a complex solid exhibiting incongruent dissolution behaviour. In this report, we have demonstrated the implementation of a solid-solution CSH gel model within a geochemical transport modelling framework using the Raiden computer code to investigate cement/concrete-groundwater interactions. The modelling conducted here shows that it is possible to couple various conceptual models for the evolution of physical properties of concrete with a solid solution model for cement degradation in a fully coupled geochemical transport model to describe the interaction of cement/concrete engineered barriers with groundwater. The results show that changes to the conceptual models and flow rates can give rise to very different evolutions. Most simulations were carried out at a reduced 'experimental' scale rather than full repository scale. The work has shown the possibility to investigate also the changing physical properties of degrading cement. To further develop the model more emphasis is needed on kinetics and the detailed development of a nearly clogged pore space. Modelling of the full repository scale could be another way forward to understand the behaviour of degrading concrete. A general conclusion is that the combined effects of chemical evolution and physical degradation should be analysed in performance assessments of cementitious repositories. Moreover, the project results will be used as one basis in coming reviews of SKB's safety assessments of repositories for spent fuel and low-and intermediate level waste

Volumetric property of glycine, L-serine, L-alanine and L-proline in aqueous solutions of 1-phenylpiperazinium tetrafluoroborate

International Nuclear Information System (INIS)

Xie, Hujun; Zhao, Lijiang; Liu, Chengcheng; Cao, Yifan; Lu, Xiaoxing; Lei, Qunfang; Fang, Wenjun

2016-01-01

Highlights: • Volumetric property of four amino acids in aqueous solutions of [Phpi][BF_4] were measured. • The standard partial molar volume, transparent partial molar volume and hydration number were calculated. • [Phpi][BF_4] interacts strongly with four kinds of amino acids. • Hydrophilic–hydrophobic and hydrophobic–hydrophobic interactions play the dominant roles in ternary systems. • The ternary systems are generated via multiple hydrogen bond interactions. - Abstract: The densities of aqueous solutions of glycine, L-serine, L-alanine, L-proline with the ionic liquid (IL), 1-phenylpiperazinium tetrafluoroborate ([Phpi][BF_4]) at the IL concentrations of (0.025, 0.055 and 0.100) mol·kg"−"1 have been measured at the temperatures of (298.15, 303.15 and 308.15) K. On the basis of the experimental results, the apparent molar volume (V_Φ), standard partial molar volume (V_Φ"0), transfer partial molar volume (Δ_t_rV_Φ"0) and hydration number (n_H) have been calculated. The hydrophilic–hydrophilic, hydrophobic–hydrophilic and hydrophobic–hydrophobic interactions are involved in the studied systems of {[Phpi][BF_4] + amino acids + H_2O. These volumetric parameters can help to understand the mixing effects and other complex biological processes between amino acids and ionic liquid aqueous solution.

Solution properties of a heteropolysaccharide extracted from pumpkin (Cucurbita pepo, lady godiva).

Science.gov (United States)

Song, Yi; Zhao, Jing; Ni, Yuanying; Li, Quanhong

2015-11-05

A water-soluble galactoglucofucomannan was extracted from pumpkin (Cucurbita pepo, lady godiva variety). GC-MS analysis indicated that the polysaccharide was composed of 1,6-linked-glucosyl, 1,2,6-linked-mannosyl, 1,3,6-linked-mannosyl, 1,2,6-linked-galactosyl, 1,2,6-linked-galactosyl, terminal fucosyl and terminal glucose. The solution properties of the polysaccharide were studied systematically by using size-exclusion chromatography combined with multi-angle laser light scattering, viscometry and dynamic light scattering at 25 °C. The weight average molecular masses (Mw), intrinsic viscosity [η], radius of gyration (Rg) and hydrodynamic radius (Rh) were found to be 12.7 × 10(5)g/mol, 780 ml/g, 68 nm and 116 nm, respectively. The fraction dimension and value of ρ (Rg/Rh) of the polysaccharide revealed that it existed in a sphere-like conformation in distilled water. The dependence of zero shear specific viscosity on the coil overlap parameter was analyzed using different models. Furthermore, degradation of samples upon autoclaving has been observed and quantified by intrinsic viscosity determination and SEC-MALLS. Copyright © 2015 Elsevier Ltd. All rights reserved.

The effect of the solution flow rate on the properties of zinc oxide (ZnO) thin films deposited by ultrasonic spray

International Nuclear Information System (INIS)

Attaf, A.; Benkhetta, Y.; Saidi, H.; Bouhdjar, A.; Bendjedidi, H.; Nouadji, M.; Lehraki, N.

2015-01-01

In this work, we used a system based on ultrasonic spray pyrolysis technique. By witch, we have deposited thin films of zinc oxide (ZnO) with the variation of solution flow rate from 50 ml / h to 150 ml / h, and set other parameters such as the concentration of the solution, the deposition time, substrate temperature and the nozzel -substrate distance. In order to study the influence of the solution flow rate on the properties of the films produced, we have several characterization techniques such as X-ray diffraction to determine the films structure, the scanning electron microscopy SEM for the morphology of the surfaces, EDS spectroscopy for the chemical composition, UV-Visible-Nir spectroscopy for determination the optical proprieties of thin films.The experimental results show that: the films have hexagonal structure at the type (wurtzite), the average size of grains varies from 20.11 to 32.45 nm, the transmittance of the films equals 80% in visible rang and the band gap is varied between 3.274 and 3.282 eV, when the solution flow rate increases from 50 to 150 ml/h

The effect of the solution flow rate on the properties of zinc oxide (ZnO) thin films deposited by ultrasonic spray

Science.gov (United States)

Attaf, A.; Benkhetta, Y.; Saidi, H.; Bouhdjar, A.; Bendjedidi, H.; Nouadji, M.; Lehraki, N.

2015-03-01

In this work, we used a system based on ultrasonic spray pyrolysis technique. By witch, we have deposited thin films of zinc oxide (ZnO) with the variation of solution flow rate from 50 ml / h to 150 ml / h, and set other parameters such as the concentration of the solution, the deposition time, substrate temperature and the nozzel -substrate distance. In order to study the influence of the solution flow rate on the properties of the films produced, we have several characterization techniques such as X-ray diffraction to determine the films structure, the scanning electron microscopy SEM for the morphology of the surfaces, EDS spectroscopy for the chemical composition, UV-Visible-Nir spectroscopy for determination the optical proprieties of thin films.The experimental results show that: the films have hexagonal structure at the type (wurtzite), the average size of grains varies from 20.11 to 32.45 nm, the transmittance of the films equals 80% in visible rang and the band gap is varied between 3.274 and 3.282 eV, when the solution flow rate increases from 50 to 150 ml/h.

Application of thermodynamic models to study micellar properties of sodium perfluoroalkyl carboxylates in aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Gonzalez-Perez, Alfredo [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: alf@usc.es; 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); Romero, Maria J. [Department of Inorganic Chemistry, Faculty of Chemistry, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); 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); 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)

2005-06-27

Sodium perfluoroalkyl carboxylates (CnFONa) with n = 6, 9, 10 have been studied by conductivity measurements at different temperatures. The Krafft point was determined for C9FONa and C10FONa at the highest concentration studied by measuring the temperature dependence of the specific conductivity. The critical micelle concentration (cmc) and the ionization degree of the micelle ({beta}) were estimated from conductivity vs. molality plots at different temperatures. Using these data and previous results on temperature dependence of cmc and {beta} of sodium perfluoroheptanoate and perfluorooctanoate, different models were applied to obtain the thermodynamic properties of micellization. The results are discussed in terms of alkyl chain length.

Application of thermodynamic models to study micellar properties of sodium perfluoroalkyl carboxylates in aqueous solutions

International Nuclear Information System (INIS)

Gonzalez-Perez, Alfredo; Ruso, Juan M.; Romero, Maria J.; Blanco, Elena; Prieto, Gerardo; Sarmiento, Felix

2005-01-01

Sodium perfluoroalkyl carboxylates (CnFONa) with n = 6, 9, 10 have been studied by conductivity measurements at different temperatures. The Krafft point was determined for C9FONa and C10FONa at the highest concentration studied by measuring the temperature dependence of the specific conductivity. The critical micelle concentration (cmc) and the ionization degree of the micelle (β) were estimated from conductivity vs. molality plots at different temperatures. Using these data and previous results on temperature dependence of cmc and β of sodium perfluoroheptanoate and perfluorooctanoate, different models were applied to obtain the thermodynamic properties of micellization. The results are discussed in terms of alkyl chain length

Existence of bounded solutions of Neumann problem for a nonlinear degenerate elliptic equation

Directory of Open Access Journals (Sweden)

Salvatore Bonafede

2017-10-01

Full Text Available We prove the existence of bounded solutions of Neumann problem for nonlinear degenerate elliptic equations of second order in divergence form. We also study some properties as the Phragmen-Lindelof property and the asymptotic behavior of the solutions of Dirichlet problem associated to our equation in an unbounded domain.

Surface micro-dissolve method of imparting self-cleaning property to cotton fabrics in NaOH/urea aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Fan, Tao; Hu, Ruimin; Zhao, Zhenyun [College of Textile & Garment, Southwest University, 400716, Chongqing (China); Liu, Yiping [College of Textile & Garment, Southwest University, 400716, Chongqing (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, 400716, Chongqing (China); Lu, Ming, E-mail: lumingswu@163.com [College of Textile & Garment, Southwest University, 400716, Chongqing (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, 400716, Chongqing (China)

2017-04-01

Highlights: • A novel micro-dissolved process was carried out to embedding commercial titanium dioxide nanoparticles into cotton fabric with NaOH/urea aqueous solution. • X-ray diffraction pattern of modified fabrics shown that the cellulose structure of modified fabrics had not changed. • Modified cotton fabrics demonstrated favourable photocatalytic self-cleaning performance while tensile strength and whiteness of treated fabrics also expressed an increasement slightly. - Abstract: A simple and economical micro-dissolved process of embedding titanium dioxide (TiO{sub 2}) nanoparticles into surface zone of cotton fabrics was developed. TiO{sub 2} was coated on cotton fabrics in 7% wt NaOH/12% wt urea aqueous solution at low temperature. Photocatalytic efficiency of cotton fabrics treated with TiO{sub 2} nanoparticles was studied upon measuring the photocatalytic decoloration of Rhodamine B (RhB) under ultraviolet irradiation. Self-cleaning property of cotton fabric coated with TiO{sub 2} was evaluated with color depth of samples (K/S value). The treated fabrics were characterized using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), Fourier transform infrared spectroscopy (FITR), tensile strength, stiffness and whiteness. The results indicated, TiO{sub 2} nanoparticles could be embedded on the surface layer of cotton fabrics throuth surface micro-dissolve method. Treated cotton fabrics possessed distinct photocatalytic efficiency and self-cleaning properties. Tensile strength and whiteness of modified cotton fabrics appeared moderately increasement.

Thermoluminescence properties of Li2B4O7:Cu, B phosphor synthesized using solution combustion technique

International Nuclear Information System (INIS)

Ozdemir, A.; Altunal, V.; Kurt, K.; Depci, T.; Yu, Y.; Lawrence, Y.; Nur, N.; Guckan, V.; Yegingil, Z.

2017-01-01

To determine the effects of various concentrations of the activators copper (Cu) and boron (B) on the thermoluminescence (TL) properties of lithium tetraborate, the phosphor was first synthesized and doped with five different concentrations of copper (0.1–0.005 wt%) using solution combustion method. 0.01 wt% Cu was the concentration which showed the most significant increase in the sensitivity of the phosphor. The second sort of Li 2 B 4 O 7 :Cu material was prepared by adding B (0.001–0.03 wt%) to it. The newly developed copper-boron activated lithium tetraborate (Li 2 B 4 O 7 :Cu, B) material with 0.01 wt% Cu and 0.001 wt% B impurity concentrations was shown to have promise as a TL phosphor. The material formation was examined using powder x-Ray Diffraction (XRD) analysis and Scanning Electron Microscope (SEM) imaging. Fourier Transform Infrared (FT-IR) spectrum of the synthesized polycrystalline powder sample was also recorded. The TL glow curves were analyzed to determine various dosimetric characteristics of the synthesized luminophosphors. The dose response increased in a “linear” way with the beta-ray exposure between 0.1–20 Gy, a dose range being interested in medical dosimetry. The response with changing photon and electron energy was studied. The rate of decay of the TL signal was investigated both for dark storage and under direct sunlight. Li 2 B 4 O 7 :Cu, B showed no individual variation of response in 9 recycling measurements. The fluorescence spectrum was determined. The kinetic parameters were estimated by different methods and the results discussed. The studied properties of synthesized Li 2 B 4 O 7 :Cu, B were found all favorable for dosimetric purposes. - Highlights: • Li 2 B 4 O 7 :Cu, B synthesis using solution combustion method with various concentrations. • Structure analysis of Li 2 B 4 O 7 :Cu, B using XRD, SEM and FTIR methods. • Investigation of thermoluminescent properties of Li 2 B 4 O 7 :Cu, B. • Relatively good

Polarimetry as a tool for the study of solutions of chiral solutes.

Science.gov (United States)

Orlova, Anna V; Andrade, Renato R; da Silva, Clarissa O; Zinin, Alexander I; Kononov, Leonid O

2014-01-13

Optical rotation of aqueous solutions of D-levoglucosan was studied experimentally in the 0.03-4.0 mol L(-1) concentration range and a nonlinear concentration dependence of specific optical rotation (SR) was revealed. Discontinuities observed in the concentration plot of SR (at 0.1, 0.3, 0.5, 1.0, and 2.0 mol L(-1)) are well correlated with those found by static and dynamic light scattering and identify concentration ranges in which different solution domains (supramers) may exist. The average SR experimental value for a D-levoglucosan aqueous solution ([α]D(28) -58.5±8.7 deg dm(-1) cm(-3) g(-1)) was found to be in good agreement with values obtained by theoretical calculation (TD-DFT/GIAO) of SR for 15 different conformers revealed by conformational sampling at the PCM/B3LYP/6-311++G(2d,2p)//B3LYP/6-31+G(d,p) level, which were shown to be strongly affected by the solvation microenvironment (0, 1, 2, and 3 explicit solvent molecules considered) due to local geometrical changes induced in the solute molecule. This exceptionally high sensitivity of SR makes polarimetry a unique method capable of sensing changes in the structure of supramers detected in this study. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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}.

Structure-property relationships of new bismuth and lead oxide based perovskite ternary solid solutions

Science.gov (United States)

Dwivedi, Akansha

) performed on these compositions show subdomain modulation contrast suggesting the presence of localized and correlated spatial fluctuations in the spontaneous strain. In the xBMT-yBZT-zPT system, very small rhombohedral region in the room temperature phase diagram has been observed. Owing to the limited solid solubility, only a part of the phase diagram could be explored. Compositions on pseudobinary xPT-(1-x)[0.9BMT-0.1BZT] has been successfully fabricated and characterized. High c/a ratio of 1.04 has been observed for a surprisingly low tolerance factor of 0.9732. Transition temperature trends have been established from DSC and dielectric data along this pseudobinary line. The following trend in the TC has been observed with the increase in non PT end member that has been divided into three zones: in Zone I TC increases, in Zone II it decreases, and in the Zone III, two transition temperatures are observed. From the TEM investigation, it has been noted that these compositions exhibit subdomain modulations which reflects the presence of spontaneous strain. These modulations increase with the increase in non PT end member, and at certain composition along pseudobinary, both macro and micro domains structure can be observed. Compositions in the rhombohedral phase of xBMT-yBZT-zPT show dramatic changes in dielectric and piezoelectric properties when quenched from high temperature. Samples quenched from temperature range 650°C-900°C show classical ferroelectric switching behavior, which is not observed on either side of this temperature range. These quenched states are however, unstable in nature and lose their ferroelectric properties when heated to a temperature as low as 400°C. Structural analysis by TEM shows varied domain structures for samples quenched from different temperatures. Evidences of tilt transitions and intermediate phases have also been observed in the TEM study. New insights into solid solution development and defect metastability are gained and discussed

Electrochemically Controlled Ion-exchange Property of Carbon Nanotubes/Polypyrrole Nanocomposite in Various Electrolyte Solutions

Energy Technology Data Exchange (ETDEWEB)

Choi, Daiwon [Pacific Northwest National Laboratory, 902 Battelle Boulevard P.O. Box 999 Richland WA 99352 USA; Zhu, Chengzhou [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920 United States; Fu, Shaofang [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920 United States; Du, Dan [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920 United States; Engelhard, Mark H. [Pacific Northwest National Laboratory, 902 Battelle Boulevard P.O. Box 999 Richland WA 99352 USA; Lin, Yuehe [Pacific Northwest National Laboratory, 902 Battelle Boulevard P.O. Box 999 Richland WA 99352 USA; School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920 United States

2016-09-15

The electrochemically controlled ion-exchange properties of multi-wall carbon nanotube (MWNT)/electronically conductive polypyrrole (PPy) polymer composite in the various electrolyte solutions have been investigated. The ion-exchange behavior, rate and capacity of the electrochemically deposited polypyrrole with and without carbon nanotube (CNT) were compared and characterized using cyclic voltammetry (CV), chronoamperometry (CA), electrochemical quartz crystal microbalance (EQCM), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It has been found that the presence of carbon nanotube backbone resulted in improvement in ion-exchange rate, stability of polypyrrole, and higher anion loading capacity per PPy due to higher surface area, electronic conductivity, porous structure of thin film, and thinner film thickness providing shorter diffusion path. Chronoamperometric studies show that electrically switched anion exchange could be completed more than 10 times faster than pure PPy thin film. The anion selectivity of CNT/PPy film is demonstrated using X-ray photoelectron spectroscopy (XPS).

Fast solution combustion synthesis of porous NaFeTi3O8 with superior sodium storage properties

Science.gov (United States)

Zhao, Jin-Bao; Li, Xue; Xiao, Qian

2018-01-01

In this work, NaFeTi3O8 with three-dimensional porous net-like sheet morphology is firstly prepared by a simple and effective solution combustion method. Encouragingly, when being assessed as an anode electrode for sodium ion batteries, the NaFeTi3O8 net-like sheet composite exhibits superior electrochemical properties. We also study the effect of the combustion fuel glycine. The results indicate that the NaFeTi3O8 composite tends to be porous with glycine as the combustion fuel, which displays more excellent long cyclic stability (discharge capacity of 91 mA h g-1 after 1000 cycles at the current density of 0.5 A g-1) and superior rate performance (84.4 mA h g-1 even at 1.6 A g-1) than that of NaFeTi3O8 without glycine as the combustion agent. The enhanced electrochemical properties could be ascribed to the unique porous morphology, which achieves better electrolyte infiltration and faster ion diffusion. [Figure not available: see fulltext.

Thermochemical study of aqueous solutions of lithium diclofenac at 293.15-318.15 K

Science.gov (United States)

Manin, N. G.; Perlovich, G. L.; Fini, A.

2013-04-01

The enthalpies of solution and dilution of aqueous solutions of lithium diclofenac (LiDC) are measured in the concentration range of 0.002-0.047 m at 293.15, 298.15, 308.15, and 318.5 K using an isoperibolic calorimeter. The heat capacity of solid LiDC in the temperature range of 273.15-373.15 K is determined using a DSC 204 F1 Phoenix differential scanning calorimeter (NETZSCH, Germany). The virial coefficients of the enthalpy characteristics of a water-LiDC solution are derived in terms of the Pitzer model to calculate a wide range of thermodynamic properties of both the solution and its components. Changes in these characteristics as a function of concentration and temperature are discussed.

Volumetric properties of l-alanine, and l-valine in aqueous sucrose solutions at T=(288.15 and 308.15) K

International Nuclear Information System (INIS)

Pal, Amalendu; Kumar, Suresh

2005-01-01

Densities of l-alanine, and l-valine have been measured at T=(288.15 and 308.15) K in aqueous sucrose solutions ranging from pure water to 25 mass% of sucrose. From these densities, apparent molar volumes (V φ ) and limiting partial molar volumes (V φ 0 ) of each amino acid in various aqueous sucrose solutions have been evaluated. These data were combined with the earlier reported V φ 0 values of l-alanine, and l-valine in aqueous sucrose solutions at T=298.15 K to calculate the (-bar V φ 0 /-bar T) P values. The partial molar properties of transfer (ΔV φ 0 ) from water to aqueous sucrose solutions at infinite dilution has been calculated. Transfer parameters have been interpreted in terms of solute-cosolute interactions on the basis of a cosphere overlap model. Pair and triplet interaction coefficients have also been calculated from transfer volume data

A study of semiconducting properties of hydrogen containing passive films

International Nuclear Information System (INIS)

Zeng, Y.M.; Luo, J.L.; Norton, P.R.

2004-01-01

Mott-Schottky and photoelectrochemical measurements were used to explore the effects of hydrogen and chloride ions on the electronic properties of the passive film on X70 micro-alloyed steel in a solution of 0.5 M NaHCO 3 . Mott-Schottky analyses have shown that hydrogen increases the capacitance and donor density, and decreases the flat band potential and the space charge layer thickness of the passive film. The photocurrent of the film is remarkably increased by hydrogen. The effects of hydrogen become more pronounced with an increase in the hydrogen charging current densities. Hydrogen has no noticeable effect on the band gap energy E g and the process by which hole-electron pairs are photo-generated in the film. The presence of chloride ions in the solution produces some similar effects on the electronic properties of the passive film to those observed with hydrogen, but reduces the photocurrent and increases the band gap energy of the film. No significant synergistic effects on the electronic properties of the passive film were observed in the presence of hydrogen and Cl - . These results provide very useful information for elucidating the mechanism by which hydrogen changes the properties of passive film and then promotes localized corrosion

Thermodynamic stability of radioactivity standard solutions

International Nuclear Information System (INIS)

Iroulard, M.G.

2007-04-01

The basic requirement when preparing radioactivity standard solutions is to guarantee the concentration of a radionuclide or a radioelement, expressed in the form of activity concentration (Ac = A/m (Bq/g), with A: activity and m: mass of solution). Knowledge of the law of radioactive decay and the half-life of a radionuclide or radioelement makes it possible to determine the activity concentration at any time, and this must be confirmed subsequently by measurement. Furthermore, when radioactivity standard solutions are prepared, it is necessary to establish optimal conditions of thermodynamic stability of the standard solutions. Radioactivity standard solutions are prepared by metrology laboratories from original solutions obtained from a range of suppliers. These radioactivity standard solutions must enable preparation of liquid and/or solid radioactivity standard sources of which measurement by different methods can determine, at a given instant, the activity concentration of the radionuclide or radioelement present in the solution. There are a number of constraints associated with the preparation of such sources. Here only those that relate to the physical and chemical properties of the standard solution are considered, and therefore need to be taken into account when preparing a radioactivity standard solution. These issues are considered in this document in accordance with the following plan: - A first part devoted to the chemical properties of the solutions: - the solubilization media: ultra-pure water and acid media, - the carriers: concentration, oxidation state of the radioactive element and the carrier element. - A second part describing the methodology of the preparation, packaging and storage of standard solutions: - glass ampoules: the structure of glasses, the mechanisms of their dissolution, the sorption phenomenon at the solid-solution interface, - quartz ampoules, - cleaning and packaging: cleaning solutions, internal surface coatings and

Thermodynamic stability of radioactivity standard solutions

Energy Technology Data Exchange (ETDEWEB)

Iroulard, M.G

2007-04-15

The basic requirement when preparing radioactivity standard solutions is to guarantee the concentration of a radionuclide or a radioelement, expressed in the form of activity concentration (Ac = A/m (Bq/g), with A: activity and m: mass of solution). Knowledge of the law of radioactive decay and the half-life of a radionuclide or radioelement makes it possible to determine the activity concentration at any time, and this must be confirmed subsequently by measurement. Furthermore, when radioactivity standard solutions are prepared, it is necessary to establish optimal conditions of thermodynamic stability of the standard solutions. Radioactivity standard solutions are prepared by metrology laboratories from original solutions obtained from a range of suppliers. These radioactivity standard solutions must enable preparation of liquid and/or solid radioactivity standard sources of which measurement by different methods can determine, at a given instant, the activity concentration of the radionuclide or radioelement present in the solution. There are a number of constraints associated with the preparation of such sources. Here only those that relate to the physical and chemical properties of the standard solution are considered, and therefore need to be taken into account when preparing a radioactivity standard solution. These issues are considered in this document in accordance with the following plan: - A first part devoted to the chemical properties of the solutions: - the solubilization media: ultra-pure water and acid media, - the carriers: concentration, oxidation state of the radioactive element and the carrier element. - A second part describing the methodology of the preparation, packaging and storage of standard solutions: - glass ampoules: the structure of glasses, the mechanisms of their dissolution, the sorption phenomenon at the solid-solution interface, - quartz ampoules, - cleaning and packaging: cleaning solutions, internal surface coatings and

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.

Comparative study of the various methods of preparation of silicate solution and its effect on the geopolymerization reaction

Directory of Open Access Journals (Sweden)

N. Essaidi

Full Text Available This paper is based on the characterization of synthesized geopolymer binders based on either powder or solution silicate, and the amount of water contained in synthesized binders is determined to evaluate their possibility to coat a brick. The structural evolution of the formed geopolymers was investigated using FTIR spectroscopy. The mechanical properties were evaluated using compression tests. The structural evolution ensured that the solutions prepared from silicate powder or liquid had different degrees of polymerization, which modified the polycondensation reaction of the mixture. Nevertheless, the use of aluminosilicate solutions based on powder or liquid display similar behavior in a polycondensation reaction. The obtained materials show good mechanical properties, and it is possible to deposit this binder on the brick depending on the water content. Keywords: Silicate powder, Bricks, Alkaline solution, Binders, Depolymerization, Metakaolin reactivity

Oscillation of solutions to neutral nonlinear impulsive hyperbolic equations with several delays

Directory of Open Access Journals (Sweden)

Jichen Yang

2013-01-01

Full Text Available In this article, we study oscillatory properties of solutions to neutral nonlinear impulsive hyperbolic partial differential equations with several delays. We establish sufficient conditions for oscillation of all solutions.

The effect of Mn substitution on the structure and magnetic properties of Se(Cu1-xMnx)O3 solid solution

International Nuclear Information System (INIS)

Escamilla, R; Duran, A; Rosales, M I; Moran, E; Alario-Franco, M A

2003-01-01

The effects of Mn substitution on the structure and magnetic properties of the SeMO 3 (M = Cu 1-x Mn x ) solid solution have been studied. Rietveld refinements of the x-ray diffraction patterns of these samples indicate that the manganese ions occupy copper sites. This replacement induces significant changes in the M-O bond lengths that give rise to abrupt decreases of the [M-O 6 ] octahedral distortion. In contrast, the M-O(1)-M and M-O(2)-M bond angles remain essentially constant. The magnetic behaviour of this solid solution was studied in the temperature range of 2 K 3 . At about 10% of Mn there is a change from positive to negative Weiss constant θ W that is mainly due to the [M-O 6 ] octahedral distortion introduced by the substitution of the larger Mn ions in the structure. The M- H isotherms show a weak ferromagnetism at about 52 K in SeMnO 3

LASERS, ACTIVE MEDIA: The aqueous-polyelectrolyte dye solution as an active laser medium

Science.gov (United States)

Akimov, A. I.; Saletskii, A. M.

2000-11-01

The spectral, luminescent, and lasing properties of aqueous solutions of a cationic dye rhodamine 6G with additions of anion polyelectrolytes — polyacrylic and polymethacrylic acids — are studied. It is found that the energy and spectral properties of lasing of these solutions depend on the ratio of concentrations of polyelectrolyte and molecules. It is also found that the lasing parameters of aqueous-polyelectrolyte dye solutions can be controlled by changing the structure of the molecular system. The variation in the structure of aqueous-polyelectrolyte dye solutions of rhodamine 6G resulted in an almost five-fold increase in the lasing efficiency compared to that in aqueous dye solutions.

Investigating conceptual models for physical property couplings in solid solution models of cement

Energy Technology Data Exchange (ETDEWEB)

Benbow, Steven; Watson, Claire; Savage, David [Quintesssa Ltd., Henley-on-Thames (United Kingdom)

2005-11-15

The long-term behaviour of cementitious engineered barriers is an important process to consider when modelling the migration of radionuclides from a geological repository for nuclear waste. The modelling of cement is complicated by the fact that the cement is dominated by the behaviour of calcium silicate hydrate (CSH) gel which is a complex solid exhibiting incongruent dissolution behaviour. In this report, we have demonstrated the implementation of a solid-solution CSH gel model within a geochemical transport modelling framework using the Raiden computer code to investigate cement/concrete-groundwater interactions. The modelling conducted here shows that it is possible to couple various conceptual models for the evolution of physical properties of concrete with a solid solution model for cement degradation in a fully coupled geochemical transport model to describe the interaction of cement/concrete engineered barriers with groundwater. The results show that changes to the conceptual models and flow rates can give rise to very different evolutions. Most simulations were carried out at a reduced 'experimental' scale rather than full repository scale. The work has shown the possibility to investigate also the changing physical properties of degrading cement. To further develop the model more emphasis is needed on kinetics and the detailed development of a nearly clogged pore space. Modelling of the full repository scale could be another way forward to understand the behaviour of degrading concrete. A general conclusion is that the combined effects of chemical evolution and physical degradation should be analysed in performance assessments of cementitious repositories. Moreover, the project results will be used as one basis in coming reviews of SKB's safety assessments of repositories for spent fuel and low-and intermediate level waste.

Study of structural and optical properties of PbS thin films

Science.gov (United States)

Homraruen, T.; Sudswasd, Y.; Sorod, R.; Kayunkid, N.; Yindeesuk, W.

2018-03-01

This research aimed to synthesize lead sulfide (PbS) thin films on glass slides using the successive ion layer absorption and reaction (SILAR) method. We studied the optical properties and structure of PbS thin films by changing the number of dipping cycles and the concentration of precursor solution. The results of this experiment show that different conditions have a considerable influence on the thickness and absorbance of the films. When the number of dipping cycles and the concentration of the solution are increased, film thickness and absorbance tend to become higher. The xrays diffraction pattern showed all the diffraction peaks which confirmed the face center cubic and the structure of PbS had identified. Grain size computation was used to confirm how much these conditions could be affected.

Biological and analytical studies of peritoneal dialysis solutions

Directory of Open Access Journals (Sweden)

N. Hudz

2018-04-01

Full Text Available The purpose of our work was to conduct biological and analytical studies of the peritoneal dialysis (PD solutions containing glucose and sodium lactate and establish correlations between cell viability of the Vero cell line and values of analytical indexes of the tested solutions. The results of this study confirm the cytotoxicity of the PD solutions even compared with the isotonic solution of sodium chloride, which may be due to the low pH of the solutions, presence of glucose degradation products (GDPs and high osmolarity of the solutions, and unphysiological concentrations of glucose and sodium lactate. However, it is not yet known what factors or their combination and to what extent cause the cytotoxicity of PD solutions. In the neutral red (NR test the weak, almost middle (r = -0.496 and 0.498, respectively and unexpected correlations were found between reduced viability of monkey kidney cells and increased pH of the PD solutions and between increased cell viability and increased absorbance at 228 nm of the tested PD solutions. These two correlations can be explained by a strong correlation (r = -0.948 between a decrease in pH and an increase in the solution absorbance at 228 nm. The opposite effect was observed in the MTT test. The weak, but expected correlations (r = 0.32 and -0.202, respectively were found between increased cell viability and increased pH in the PD solutions and between decreased cell viability and increased absorbance at 228 nm of the tested PD solutions. The middle and weak correlations (r = 0.56 and 0.29, respectively were detected between increased cell viability and increased lactate concentration in the NR test and MTT test. The data of these correlations can be partially explained by the fact that a correlation with a coefficient r = -0.34 was found between decreased pH in the solutions and increased lactate concentration. The very weak correlations (0.138 and 0.196, respectively were found between increased cell

Synthesis, single crystal growth and thermodynamic properties of SrNdAlO4-CaNdAlO4 solid solutions

International Nuclear Information System (INIS)

Novoselov, A.; Ryumin, M.; Pushkina, G.; Spiridonov, F.; Komissarova, L.; Zimina, G.; Pajaczkowska, A.

2005-01-01

Continuous solid solutions in the SrNdAlO 4 -CaNdAlO 4 system are formed. Powder samples of Sr x Ca 1-x NdAlO 4 (0.0≤x≤1.0) were obtained using the carbonate coprecipitation method while single crystals of Sr x Ca 1-x NdAlO 4 (x=0.0,0.162,0.392,0.687,1.0) were grown by the Czochralski method. Structural parameters and thermodynamic properties of the samples were studied by X-ray diffraction and heat flux Calvet calorimetry. Composition dependence of lattice constants was observed to follow Vegard's low. Heat of solution of the Sr x Ca 1-x NdAlO 4 samples in molten 2PbO.B 2 O 3 were measured, and enthalpies of formation and mixing were calculated. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Structural properties and adsorption capacity of holocellulose aerogels synthesized from an alkali hydroxide-urea solution

Energy Technology Data Exchange (ETDEWEB)

Kwon, Gu-Joong; Kim, Dae-Young; Hwang, Jae-Hyun; Kang, Joo-Hyon [Dongguk University, Seoul (Korea, Republic of)

2014-05-15

A tulip tree was used to synthesize a holocellulose aerogel from an aqueous alkali hydroxide-urea solution with the substitution of an organic solvent followed by freeze-drying. For comparison, the synthesized holocellulose aerogels were divided into two groups according to the source of the hydrogel, an upper suspended layer and a bottom concentrated layer of the centrifuged solution of cellulose and NaOH/urea solvents. We investigated the effects of the temperature of the pre-cooled NaOH/urea solution (i.e., dissolution temperature) on the pore structure and the adsorption capacity of the holocellulose aerogel. A nano-fibrillar network structure of the holocellulose aerogel was observed, with little morphological difference in pore structure for different dissolution temperatures. Both micropores and mesopores were observed in the holocellulose aerogel. The specific surface area of the holocellulose aerogel was generally greater at lower dissolution temperatures. In a series of adsorption tests using methylene blue, the holocellulose aerogel showed the greatest adsorption capacity at the lowest dissolution temperature tested ( -2 .deg. C). However, the dissolution temperature generally had little effect on the adsorption capacity. The holocellulose aerogel produced from the upper suspended layer of the centrifuged hydrogel solution showed a greater porosity and adsorption capacity than the one produced from the bottom concentrated layer. Overall, the aerogel made by utilizing a delignified tulip tree display a high surface area and a high adsorption property, indicating its possible application in eco-friendly adsorption materials.

Structural properties and adsorption capacity of holocellulose aerogels synthesized from an alkali hydroxide-urea solution

International Nuclear Information System (INIS)

Kwon, Gu-Joong; Kim, Dae-Young; Hwang, Jae-Hyun; Kang, Joo-Hyon

2014-01-01

A tulip tree was used to synthesize a holocellulose aerogel from an aqueous alkali hydroxide-urea solution with the substitution of an organic solvent followed by freeze-drying. For comparison, the synthesized holocellulose aerogels were divided into two groups according to the source of the hydrogel, an upper suspended layer and a bottom concentrated layer of the centrifuged solution of cellulose and NaOH/urea solvents. We investigated the effects of the temperature of the pre-cooled NaOH/urea solution (i.e., dissolution temperature) on the pore structure and the adsorption capacity of the holocellulose aerogel. A nano-fibrillar network structure of the holocellulose aerogel was observed, with little morphological difference in pore structure for different dissolution temperatures. Both micropores and mesopores were observed in the holocellulose aerogel. The specific surface area of the holocellulose aerogel was generally greater at lower dissolution temperatures. In a series of adsorption tests using methylene blue, the holocellulose aerogel showed the greatest adsorption capacity at the lowest dissolution temperature tested ( -2 .deg. C). However, the dissolution temperature generally had little effect on the adsorption capacity. The holocellulose aerogel produced from the upper suspended layer of the centrifuged hydrogel solution showed a greater porosity and adsorption capacity than the one produced from the bottom concentrated layer. Overall, the aerogel made by utilizing a delignified tulip tree display a high surface area and a high adsorption property, indicating its possible application in eco-friendly adsorption materials.

The radial-hedgehog solution in Landau–de Gennes' theory for nematic liquid crystals

KAUST Repository

MAJUMDAR, APALA

2011-09-06

We study the radial-hedgehog solution in a three-dimensional spherical droplet, with homeotropic boundary conditions, within the Landau-de Gennes theory for nematic liquid crystals. The radial-hedgehog solution is a candidate for a global Landau-de Gennes minimiser in this model framework and is also a prototype configuration for studying isolated point defects in condensed matter physics. The static properties of the radial-hedgehog solution are governed by a non-linear singular ordinary differential equation. We study the analogies between Ginzburg-Landau vortices and the radial-hedgehog solution and demonstrate a Ginzburg-Landau limit for the Landau-de Gennes theory. We prove that the radial-hedgehog solution is not the global Landau-de Gennes minimiser for droplets of finite radius and sufficiently low temperatures and prove the stability of the radial-hedgehog solution in other parameter regimes. These results contain quantitative information about the effect of geometry and temperature on the properties of the radial-hedgehog solution and the associated biaxial instabilities. © Copyright Cambridge University Press 2011.

The radial-hedgehog solution in Landau–de Gennes' theory for nematic liquid crystals

KAUST Repository

MAJUMDAR, APALA

2011-01-01

We study the radial-hedgehog solution in a three-dimensional spherical droplet, with homeotropic boundary conditions, within the Landau-de Gennes theory for nematic liquid crystals. The radial-hedgehog solution is a candidate for a global Landau-de Gennes minimiser in this model framework and is also a prototype configuration for studying isolated point defects in condensed matter physics. The static properties of the radial-hedgehog solution are governed by a non-linear singular ordinary differential equation. We study the analogies between Ginzburg-Landau vortices and the radial-hedgehog solution and demonstrate a Ginzburg-Landau limit for the Landau-de Gennes theory. We prove that the radial-hedgehog solution is not the global Landau-de Gennes minimiser for droplets of finite radius and sufficiently low temperatures and prove the stability of the radial-hedgehog solution in other parameter regimes. These results contain quantitative information about the effect of geometry and temperature on the properties of the radial-hedgehog solution and the associated biaxial instabilities. © Copyright Cambridge University Press 2011.

Molecular thermodynamics using fluctuation solution theory

DEFF Research Database (Denmark)

Ellegaard, Martin Dela

. The framework relates thermodynamic variables to molecular pair correlation functions of liquid mixtures. In this thesis, application of the framework is illustrated using two approaches: 1. Solubilities of solid solutes in mixed solvent systems are determined from fluctuation solution theory application......Properties of chemicals and their mutual phase equilibria are critical variables in process design. Reliable estimates of relevant equilibrium properties, from thermodynamic models, can form the basis of good decision making in the development phase of a process design, especially when access...... to relevant experimental data is limited. This thesis addresses the issue of generating and using simple thermodynamic models within a rigorous statistical mechanical framework, the so-called fluctuation solution theory, from which relations connecting properties and phase equilibria can be obtained...

Effect of acidic aqueous solution on chemical and physical properties of polyamide NF membranes

Science.gov (United States)

Jun, Byung-Moon; Kim, Su Hwan; Kwak, Sang Kyu; Kwon, Young-Nam

2018-06-01

This work was systematically investigated the effects of acidic aqueous solution (15 wt% sulfuric acid as model wastewater from smelting process) on the physical and chemical properties of commercially available nanofiltration (NF) polyamide membranes, using piperazine (PIP)-based NE40/70 membranes and m-phenylene diamine (MPD)-based NE90 membrane. Surface properties of the membranes were studied before and after exposure to strong acid using various analytical tools: Scanning Electron Microscopy (SEM), Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), contact angle analyzer, and electrophoretic light scattering spectrophotometer. The characterization and permeation results showed piperazine-based NE40/70 membranes have relatively lower acid-resistance than MPD-based NE90 membrane. Furthermore, density functional theory (DFT) calculation was also conducted to reveal the different acid-tolerances between the piperazine-based and MPD-based polyamide membranes. The easiest protonation was found to be the protonation of oxygen in piperazine-based monomer, and the N-protonation of the monomer had the lowest energy barrier in the rate determining step (RDS). The calculations were well compatible with the surface characterization results. In addition, the energy barrier in RDS is highly correlated with the twist angle (τD), which determines the delocalization of electrons between the carbonyl πCO bond and nitrogen lone pair, and the tendency of the twist angle was also maintained in longer molecules (dimer and trimer). This study clearly explained why the semi-aromatic membrane (NE40/70) is chemically less stable than the aromatic membrane (NE90) given the surface characterizations and DFT calculation results.

Study of physical and sound absorbing property of epoxy blended coir dust biocomposite

Science.gov (United States)

Nath, G.; Mishra, S. P.

2016-09-01

Reinforcement biocomposite has gained more attention recently due to its low cost, abundantly availability, low density, specific properties, easy method of separation, enhanced energy recovery, CO2 neutrality, biodegradability and recyclable in nature. As a waste product of coconut fruit, the coconut coir dust (CCD) obtained from the coconut husk. The biocomposite material prepared from the CCD modified with the proper blended solution with the help of ultrasonic technique. The study of adiabatic compressibility of acetone / water (70/30) worth its blending property for bleaching of CCD. The biocomposite material of CCD was prepared with epoxy resin. The different physical properties such as sound absorption coefficient, thermal conductivity and electrical conductivity were measured. The morphological study of biocomposite and measurement of sound absorption coefficient shows good evidence of sound absorbing characteristics of biocomposite of CCD. The sound absorption property of composite material shows a significant result where as the thermal conductivity and electrical conductivity executes a weak result. Thus biocomposite of CCD can acts as a good sound absorber and band conductor of heat and electric current.

Opalescence in monoclonal antibody solutions and its correlation with intermolecular interactions in dilute and concentrated solutions.

Science.gov (United States)

Raut, Ashlesha S; Kalonia, Devendra S

2015-04-01

Opalescence indicates physical instability of a formulation because of the presence of aggregates or liquid-liquid phase separation in solution and has been reported for monoclonal antibody (mAb) formulations. Increased solution opalescence can be attributed to attractive protein-protein interactions (PPIs). Techniques including light scattering, AUC, or membrane osmometry are routinely employed to measure PPIs in dilute solutions, whereas opalescence is seen at relatively higher concentrations, where both long- and short-range forces contribute to overall PPIs. The mAb molecule studied here shows a unique property of high opalescence because of liquid-liquid phase separation. In this study, opalescence measurements are correlated to PPIs measured in diluted and concentrated solutions using light scattering (kD ) and high-frequency rheology (G'), respectively. Charges on the molecules were calculated using zeta potential measurements. Results indicate that high opalescence and phase separation are a result of the attractive interactions in solution; however, the presence of attractive interactions do not always imply phase separation. Temperature dependence of opalescence suggests that thermodynamic contribution to opalescence is significant and Tcloud can be utilized as a potential tool to assess attractive interactions in solution. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Reference interaction site model with hydrophobicity induced density inhomogeneity: An analytical theory to compute solvation properties of large hydrophobic solutes in the mixture of polyatomic solvent molecules

International Nuclear Information System (INIS)

Cao, Siqin; Sheong, Fu Kit; Huang, Xuhui

2015-01-01

Reference interaction site model (RISM) has recently become a popular approach in the study of thermodynamical and structural properties of the solvent around macromolecules. On the other hand, it was widely suggested that there exists water density depletion around large hydrophobic solutes (>1 nm), and this may pose a great challenge to the RISM theory. In this paper, we develop a new analytical theory, the Reference Interaction Site Model with Hydrophobicity induced density Inhomogeneity (RISM-HI), to compute solvent radial distribution function (RDF) around large hydrophobic solute in water as well as its mixture with other polyatomic organic solvents. To achieve this, we have explicitly considered the density inhomogeneity at the solute-solvent interface using the framework of the Yvon-Born-Green hierarchy, and the RISM theory is used to obtain the solute-solvent pair correlation. In order to efficiently solve the relevant equations while maintaining reasonable accuracy, we have also developed a new closure called the D2 closure. With this new theory, the solvent RDFs around a large hydrophobic particle in water and different water-acetonitrile mixtures could be computed, which agree well with the results of the molecular dynamics simulations. Furthermore, we show that our RISM-HI theory can also efficiently compute the solvation free energy of solute with a wide range of hydrophobicity in various water-acetonitrile solvent mixtures with a reasonable accuracy. We anticipate that our theory could be widely applied to compute the thermodynamic and structural properties for the solvation of hydrophobic solute

Nanostructured ZnO films: A study of molecular influence on transport properties by impedance spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Sappia, Luciano D.; Trujillo, Matias R. [Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET, Chacabuco 461, T4000ILI San Miguel de Tucumán (Argentina); Laboratorio de Medios e Interfases (LAMEIN), Departamento de Bioingeniería, Fac. de Cs. Exactas y Tecnología, Universidad Nacional de Tucumán, Av. Independencia 1800, 4000 San Miguel de Tucumán (Argentina); Lorite, Israel [Division of Superconductivity and Magnetism, Institute for Experimental Physics II, University of Leipzig, Linnéstrasse 5, 04103 Leipzig (Germany); Madrid, Rossana E., E-mail: rmadrid@herrera.unt.edu.ar [Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET, Chacabuco 461, T4000ILI San Miguel de Tucumán (Argentina); Laboratorio de Medios e Interfases (LAMEIN), Departamento de Bioingeniería, Fac. de Cs. Exactas y Tecnología, Universidad Nacional de Tucumán, Av. Independencia 1800, 4000 San Miguel de Tucumán (Argentina); Tirado, Monica [NanoProject and Laboratorio de Nanomateriales y Propiedades Dieléctricas, Departamento de Física, Universidad Nacional de Tucumán, Avenida Independencia 1800, Tucumán (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); and others

2015-10-15

Graphical abstract: - Highlights: • We study electrical transport in nanostructured ZnO films by impedance spectroscopy. • Bioaggregates on the surface produce strong changes in film transport properties. • This behavior is explained by modeling data with RC parallel circuits. • Electrical responses of ZnO films to aggregates are promising for biosensing. - Abstract: Nanomaterials based on ZnO have been used to build glucose sensors due to its high isoelectric point, which is important when a protein like Glucose Oxidase (GOx) is attached to a surface. It also creates a biologically friendly environment to preserve the activity of the enzyme. In this work we study the electrical transport properties of ZnO thin films (TFs) and single crystals (SC) in contact with different solutions by using impedance spectroscopy. We have found that the composition of the liquid, by means of the charge of the ions, produces strong changes in the transport properties of the TF. The enzyme GOx and phosphate buffer solutions have the major effect in the conduction through the films, which can be explained by the entrapment of carriers at the grain boundaries of the TFs. These results can help to design a new concept in glucose biosensing.

Electronic-property dependent interactions between tetracycline and graphene nanomaterials in aqueous solution.

Science.gov (United States)

He, Lin; Liu, Fei-Fei; Zhao, Mengyao; Qi, Zhen; Sun, Xuefei; Afzal, Muhammad Zaheer; Sun, Xiaomin; Li, Yanhui; Hao, Jingcheng; Wang, Shuguang

2018-04-01

Understanding the interactions between graphene nanomaterials (GNMs) and antibiotics in aqueous solution is critical to both the engineering applications of GNMs and the assessment of their potential impact on the fate and transport of antibiotics in the aquatic environment. In this study, adsorption of one common antibiotic, tetracycline, by graphene oxide (GO) and reduced graphene oxide (RGO) was examined with multi-walled carbon nanotubes (MWCNTs) and graphite as comparison. The results showed that the tetracycline adsorption capacity by the four selected carbonaceous materials on the unit mass basis followed an order of GO>RGO>MWCNTs>graphite. Upon normalization by surface area, graphite, RGO and MWCNTs had almost the same high tetracycline adsorption affinity while GO exhibited the lowest. We proposed π-electron-property dependent interaction mechanisms to explain the observed different adsorption behaviors. Density functional theory (DFT) calculations suggested that the oxygen-containing functional groups on GO surface reduced its π-electron-donating ability, and thus decreased the π-based interactions between tetracycline and GO surface. Comparison of adsorption efficiency at different pH indicated that electrostatic interaction also played an important role in tetracycline-GO interactions. Site energy analysis confirmed a highly heterogeneous distribution of the binding sites and strong tetracycline binding affinity of GO surface. Copyright © 2017. Published by Elsevier B.V.

Reactive solute transport in an asymmetrical fracture-rock matrix system

Science.gov (United States)

Zhou, Renjie; Zhan, Hongbin

2018-02-01

The understanding of reactive solute transport in a single fracture-rock matrix system is the foundation of studying transport behavior in the complex fractured porous media. When transport properties are asymmetrically distributed in the adjacent rock matrixes, reactive solute transport has to be considered as a coupled three-domain problem, which is more complex than the symmetric case with identical transport properties in the adjacent rock matrixes. This study deals with the transport problem in a single fracture-rock matrix system with asymmetrical distribution of transport properties in the rock matrixes. Mathematical models are developed for such a problem under the first-type and the third-type boundary conditions to analyze the spatio-temporal concentration and mass distribution in the fracture and rock matrix with the help of Laplace transform technique and de Hoog numerical inverse Laplace algorithm. The newly acquired solutions are then tested extensively against previous analytical and numerical solutions and are proven to be robust and accurate. Furthermore, a water flushing phase is imposed on the left boundary of system after a certain time. The diffusive mass exchange along the fracture/rock matrixes interfaces and the relative masses stored in each of three domains (fracture, upper rock matrix, and lower rock matrix) after the water flushing provide great insights of transport with asymmetric distribution of transport properties. This study has the following findings: 1) Asymmetric distribution of transport properties imposes greater controls on solute transport in the rock matrixes. However, transport in the fracture is mildly influenced. 2) The mass stored in the fracture responses quickly to water flushing, while the mass stored in the rock matrix is much less sensitive to the water flushing. 3) The diffusive mass exchange during the water flushing phase has similar patterns under symmetric and asymmetric cases. 4) The characteristic distance

The study of CO2 absorption intensification using porous media material in aqueous AMP solution

Directory of Open Access Journals (Sweden)

Min Xiao

2018-03-01

Full Text Available In this work, the performance of CO2 absorption into aqueous 2-amino-2-methyl-propanol (AMP solution was investigated by measuring the amount of CO2 in the liquid phase during CO2 absorption process to identify initial CO2 absorption rate. Then, the porous media material named as MCM41 was introduced into the amine solution to test its influence on CO2 absorption. It was found that MCM41 increased initial CO2 absorption rate and enhanced CO2 absorption process. The physico-chemical properties of MCM41 were characterized in terms of specific surface area, average pore diameter, total pore volume and chemical properties, the amount of acidic sites and the Brϕnsted/Lewis (B/L acid sites ratio. Results showed that MCM41 was a type of Lewis acid catalyst with large specific surface area and pore volume. In addition, the pKa of AMP solution with and without MCM41 was obtained using acid titration technology to help understand the effect brought by MCM41. A mechanism illustrating how MCM41 increases the CO2 absorption rate of the AMP solution was proposed and demonstrated that MCM41 is a potential material for enhancing CO2 absorption.

End-to-end self-assembly of gold nanorods in isopropanol solution: experimental and theoretical studies

Energy Technology Data Exchange (ETDEWEB)

Gordel, M., E-mail: marta.gordel@pwr.edu.pl [Wrocław University of Technology, Advanced Materials Engineering and Modelling Group, Faculty of Chemistry (Poland); Piela, K., E-mail: katarzyna.piela@pwr.edu.pl [Wrocław University of Technology, Department of Physical and Quantum Chemistry (Poland); Kołkowski, R. [Wrocław University of Technology, Advanced Materials Engineering and Modelling Group, Faculty of Chemistry (Poland); Koźlecki, T. [Wrocław University of Technology, Department of Chemical Engineering, Faculty of Chemistry (Poland); Buckle, M. [CNRS, École Normale Supérieure de Cachan, Laboratoire de Biologie et Pharmacologie Appliquée (France); Samoć, M. [Wrocław University of Technology, Advanced Materials Engineering and Modelling Group, Faculty of Chemistry (Poland)

2015-12-15

We describe here a modification of properties of colloidal gold nanorods (NRs) resulting from the chemical treatment used to carry out their transfer into isopropanol (IPA) solution. The NRs acquire a tendency to attach one to another by their ends (end-to-end assembly). We focus on the investigation of the change in position and shape of the longitudinal surface plasmon (l-SPR) band after self-assembly. The experimental results are supported by a theoretical calculation, which rationalizes the dramatic change in optical properties when the NRs are positioned end-to-end at short distances. The detailed spectroscopic characterization performed at the consecutive stages of transfer of the NRs from water into IPA solution revealed the features of the interaction between the polymers used as ligands and their contribution to the final stage, when the NRs were dispersed in IPA solution. The efficient method of aligning the NRs detailed here may facilitate applications of the self-assembled NRs as building blocks for optical materials and biological sensing.Graphical Abstract.

Sound velocity in potassium hydroxide aqueous solution

International Nuclear Information System (INIS)

Tsapuryan, Kh.D.; Aleksandrov, A.A.; Kochetkov, A.I.

1992-01-01

Measurements of ultrasonic velocities in potassium hydroxide aqueous solutions are carried out within the frames of studies on improvement of water chemistry in NPP cooling systems. Method of echo pulses superposition with acoustic path length of 41.447 mm is used for measurements. The measurements are performed at 2.6 MHz frequency. Complex temperature dependence of ultrasonic velocity is determined. Ultrasonic velocity dependence on pressure is close to linear one. The formula for calculation of thermodynamic properties of the studied solutions on the basis of experimental data obtained is proposed

Solution of diffusion equation in deformable spheroids

Energy Technology Data Exchange (ETDEWEB)

Ayyoubzadeh, Seyed Mohsen [Department of Energy Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Safari, Mohammad Javad, E-mail: iFluka@gmail.com [Department of Energy Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Vosoughi, Naser [Department of Energy Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of)

2011-05-15

Research highlights: > Developing an explicit solution for the diffusion equation in spheroidal geometry. > Proving an orthogonality relation for spheroidal eigenfunctions. > Developing a relation for the extrapolation distance in spheroidal geometry. > Considering the sphere and slab as limiting cases for a spheroid. > Cross-validation of the analytical solution with Monte Carlo simulations. - Abstract: The time-dependent diffusion of neutrons in a spheroid as a function of the focal distance has been studied. The solution is based on an orthogonal basis and an extrapolation distanced related boundary condition for the spheroidal geometry. It has been shown that spheres and disks are two limiting cases for the spheroids, for which there is a smooth transition for the systems properties between these two limits. Furthermore, it is demonstrated that a slight deformation from a sphere does not affect the fundamental mode properties, to the first order. The calculations for both multiplying and non-multiplying media have been undertaken, showing good agreement with direct Monte Carlo simulations.

Complete study of the existence and uniqueness of solutions for semilinear elliptic equations involving measures concentrated on boundary

KAUST Repository

Chen, Huyuan

2017-02-06

The purpose of this paper is to study the weak solutions of the fractional elliptic problem(Formula presented.) where (Formula presented.), (Formula presented.) or (Formula presented.), (Formula presented.) with (Formula presented.) is the fractional Laplacian defined in the principle value sense, (Formula presented.) is a bounded (Formula presented.) open set in (Formula presented.) with (Formula presented.), (Formula presented.) is a bounded Radon measure supported in (Formula presented.) and (Formula presented.) is defined in the distribution sense, i.e.(Formula presented.) here (Formula presented.) denotes the unit inward normal vector at (Formula presented.). In this paper, we prove that (0.1) with (Formula presented.) admits a unique weak solution when g is a continuous nondecreasing function satisfying(Formula presented.) Our interest then is to analyse the properties of weak solution when (Formula presented.) with (Formula presented.), including the asymptotic behaviour near (Formula presented.) and the limit of weak solutions as (Formula presented.). Furthermore, we show the optimality of the critical value (Formula presented.) in a certain sense, by proving the non-existence of weak solutions when (Formula presented.). The final part of this article is devoted to the study of existence for positive weak solutions to (0.1) when (Formula presented.) and (Formula presented.) is a bounded nonnegative Radon measure supported in (Formula presented.). We employ the Schauder’s fixed point theorem to obtain positive solution under the hypothesis that g is a continuous function satisfying(Formula presented.)-pagination

Physical properties of iodate solutions and the deliquescence of crystalline I2O5 and HIO3

Directory of Open Access Journals (Sweden)

B. J. Murray

2010-12-01

Full Text Available Secondary aerosol produced from marine biogenic sources in algal-rich coastal locations will initially be composed of iodine oxide species, most likely I2O5, or its hydrated form HIO3, formed as a result of iodine gas-phase chemistry. At present, there is no quantitative hygroscopic data for these compounds and very little data available for iodate solutions (HIO3 and I2O5 share a common aqueous phase. With increased interest in the role of such aerosol in the marine atmosphere, we have conducted studies of (i the deliquescence behaviour of crystalline HIO3 and I2O5 at 273–303 K, (ii the efflorescence behaviour of aqueous iodate solution droplets, and (iii properties (water activity, density, and viscosity of subsaturated and saturated iodate solutions. The deliquescence of I2O5 crystals at 293 K was observed to occur at a relative humidity (DRH of 80.8±1.0%, whereas for HIO3, a DRH of 85.0±1.0% was measured. These values are consistent with measured water activity values for saturated I2O5 and HIO3 solutions at 293 K of 0.80±0.01 and 0.84±0.01 respectively. At all temperatures, DRH values for HIO3 crystals were observed to be higher than for those of I2O5. The temperature-dependent DRH data, along with solubility and water activity data were used to evaluate the enthalpy of solution (ΔHsol for HIO3 and I2O5. A ΔHsol value of 8.3±0.7 kJ mol−1 was determined for HIO3 which is consistent with a literature value of 8.8 kJ mol−1. For I2O5, we report for the first time its solubility at various temperatures and ΔHsol = 12.4±0.6 kJ mol−1. The measured water activity values confirm that aqueous iodate solutions are strongly non-ideal, consistent with previous reports of complex ion formation and molecular aggregation.

Volumetric properties of itaconic acid aqueous solutions

International Nuclear Information System (INIS)

Nisenbaum, Alexander; Apelblat, Alexander; Manzurola, Emanuel

2012-01-01

Highlights: ► Densities of itaconic acid aqueous solutions in a wide range of concentrations and temperatures. ► The apparent molar volumes and the cubic expansion coefficients. ► The derivatives of isobaric heat capacities with respect to pressure. ► Changes in the structure of water when itaconic acid is dissolved. - Abstract: Densities of itaconic acid aqueous solutions were measured at 5 K intervals from T = (278.15 to 343.15) K. From the determined densities, the apparent molar volumes, the cubic expansion coefficients and the second derivatives of volume with respect to temperature which are interrelated with the derivatives of isobaric heat capacities with respect to pressure were evaluated. These derivatives were qualitatively correlated with the changes in the structure of water when itaconic acid is dissolved in it.

Evolution of ZnS Nanoparticles via Facile CTAB Aqueous Micellar Solution Route: A Study on Controlling Parameters

Directory of Open Access Journals (Sweden)

Gradzielski Michael

2008-01-01

Full Text Available Abstract Synthesis of semiconductor nanoparticles with new photophysical properties is an area of special interest. Here, we report synthesis of ZnS nanoparticles in aqueous micellar solution of Cetyltrimethylammonium bromide (CTAB. The size of ZnS nanodispersions in aqueous micellar solution has been calculated using UV-vis spectroscopy, XRD, SAXS, and TEM measurements. The nanoparticles are found to be polydispersed in the size range 6–15 nm. Surface passivation by surfactant molecules has been studied using FTIR and fluorescence spectroscopy. The nanoparticles have been better stabilized using CTAB concentration above 1 mM. Furthermore, room temperature absorption and fluorescence emission of powdered ZnS nanoparticles after redispersion in water have also been investigated and compared with that in aqueous micellar solution. Time-dependent absorption behavior reveals that the formation of ZnS nanoparticles depends on CTAB concentration and was complete within 25 min.

Study of free acidity determinations in aqueous solution

International Nuclear Information System (INIS)

Kergreis, A.

1966-04-01

The object of this work is the study of the principal methods which can be applied to the measurement of 'free' acidity. In the first part, we define the various types of acidity which can exist in aqueous solution; then, after having studied some hydrolysis reactions, we compare the value of the neutralisation pH of the hydrated cation and that of the precipitation of the hydroxide. In the second part we have started to study the determination of the acidity of an aqueous solution. After having rapidly considered the 'total' acidity determination, we deal with the problem of the 'free' acidity titration. We have considered in particular certain methods: extrapolation of the equivalent point, colorimetric titrations with or without a complexing agent, and finally the use of ion-exchange resins with mixed aqueous and solvent solutions. (author) [fr

Quinary wurtzite Zn-Ga-Ge-N-O solid solutions and their photocatalytic properties under visible light irradiation

Science.gov (United States)

Xie, Yinghao; Wu, Fangfang; Sun, Xiaoqin; Chen, Hongmei; Lv, Meilin; Ni, Shuang; Liu, Gang; Xu, Xiaoxiang

2016-01-01

Wurtzite solid solutions between GaN and ZnO highlight an intriguing paradigm for water splitting into hydrogen and oxygen using solar energy. However, large composition discrepancy often occurs inside the compound owing to the volatile nature of Zn, thereby prescribing rigorous terms on synthetic conditions. Here we demonstrate the merits of constituting quinary Zn-Ga-Ge-N-O solid solutions by introducing Ge into the wurtzite framework. The presence of Ge not only mitigates the vaporization of Zn but also strongly promotes particle crystallization. Synthetic details for these quinary compounds were systematically explored and their photocatalytic properties were thoroughly investigated. Proper starting molar ratios of Zn/Ga/Ge are of primary importance for single phase formation, high particle crystallinity and good photocatalytic performance. Efficient photocatalytic hydrogen and oxygen production from water were achieved for these quinary solid solutions which is strongly correlated with Ge content in the structure. Apparent quantum efficiency for optimized sample approaches 1.01% for hydrogen production and 1.14% for oxygen production. Theoretical calculation reveals the critical role of Zn for the band gap reduction in these solid solutions and their superior photocatalytic acitivity can be understood by the preservation of Zn in the structure as well as a good crystallinity after introducing Ge.

Solution-blown nanofiber mats from fish sarcoplasmic protein

DEFF Research Database (Denmark)

Sett, S.; Boutrup Stephansen, Karen; Yarin, A.L.

2016-01-01

In the present work, solution-blowing was adopted to form nanofibers from fish sarcoplasmic proteins (FSPs). Nanofiber mats containing different weight ratios (up to 90/10) of FSP in the FSP/nylon 6 blended nanofibers were formed from formic acid solutions, and compared to electrospun fibers made...... that the production rate of solution-blowing was increased 30-fold in relation to electrospinning. Overall, this study reveals FSP as an interesting biopolymeric alternative to synthetic polymers, and the introduction of FSP to nylon 6 provides a composite with controlled properties....

A Comparative Study on Magnetostructural Properties of Barium Hexaferrite Powders Prepared by Polyethylene Glycol

Directory of Open Access Journals (Sweden)

Zehra Durmus

2014-01-01

Full Text Available Nanocrystalline particles of barium hexaferrite were synthesized by a sol-gel combustion route using nitrate-citrate gels prepared from metal nitrates and citric acid solutions with Fe/Ba molar ratio 12. The present paper aims to study the effect of addition of polyethylene glycol (PEG solutions with different molecular weights (MW: 400, 2000, and 10.000 g/mol on magnetostructural properties of barium hexaferrite. The formation of the barium hexaferrite was inspected using X-ray diffraction (XRD analysis, Fourier transform infrared (FT-IR analysis, thermogravimetric (TGA analysis, scanning electron microscopy (SEM analysis and vibrating sample magnetometer (VSM analysis for magnetic measurements.

Exact Solutions for Einstein's Hyperbolic Geometric Flow

International Nuclear Information System (INIS)

He Chunlei

2008-01-01

In this paper we investigate the Einstein's hyperbolic geometric flow and obtain some interesting exact solutions for this kind of flow. Many interesting properties of these exact solutions have also been analyzed and we believe that these properties of Einstein's hyperbolic geometric flow are very helpful to understanding the Einstein equations and the hyperbolic geometric flow

Study of chemical and physical properties of irradiated Guar Gum

International Nuclear Information System (INIS)

Hussein, H. A. S.

2012-07-01

This study was carried out to evaluate the effect of different gamma radiation doses to decontamination of micro-organisms present in Guar Gum powder. As well as to study the effect of radiation on the chemical and physical properties of the carbohydrate components of the Gum's material. Two types of samples were used in this study (powder and liquid). All samples were collected from commercially available Guar Gum (G G), which were obtained from the company (Sudanese Guar Gum ltd). Samples putted in polyethylene tightly closed container, then irradiated by applying different doses (2.5, 5, 7.5, 10, 20,30,40,and 50 kGy) from Co-60 source at room temperature in air. And take zero kGy as control. Irradiated powder samples of (2.5, 5, 7.5, 10 kGy) were investigated for contamination by using growth media agar and the result showed that 2.5 kGy is appropriate dose to remove the contamination of the samples. And then analyzed using fourier transform infrared (FTTR) x-ray fluorescence (X RF) and spectroscopy. The FTIR spectroscopy results suggested that there were no major chemical functional group transformation during irradiation. No change occurs by using low dose as 2.5 kGy. Also evaluation impact of radiation on liquid Samples (Aqueous solutions prepared in tow concentration of 1% and 5% wv that is by exposing the samples to the same dose of gamma rays) the effect of irradiation on it were investigated by using ultra violet spectroscopy ( UV.Vis), results showed that low dose has steeply effect in solutions specially in low concentration, it was more pronoun than that in high concentration, high dose has made change similar to that it made in powder. Also for both concentrations of liquid samples and for solutions made of irradiated powder pH measured and viscosity which used in investigations of molecular weight of liquid and powder, comparing the results of impact in the form of powder with the results of effects in the solutions found that the effects of

Quantized gauge invariant periodic TDHF solutions

International Nuclear Information System (INIS)

Kan, K.-K.; Griffin, J.J.; Lichtner, P.C.; Dworzecka, M.

1979-01-01

Time-dependent Hartree-Fock (TDHF) is used to study steady state large amplitude nuclear collective motions, such as vibration and rotation. As is well known the small amplitude TDHF leads to the RPA equation. The analysis of periodicity in TDHF is not trivial because TDHF is a nonlinear theory and it is not known under what circumstances a nonlinear theory can support periodic solutions. It is also unknown whether such periodic solution, if they exist, form a continuous or a discrete set. But, these properties may be important in obtaining the energy spectrum of the collective states from the TDHF description. The periodicity and Gauge Invariant Periodicity of solutions are investigated for that class of models whose TDHF solutions depend on time through two parameters. In such models TDHF supports a continuous family of periodic solutions, but only a discrete subset of these is gauge invariant. These discrete Gauge Invariant Periodic solutions obey the Bohr-Summerfeld quantization rule. The energy spectrum of the Gauge Invariant Periodic solutions is compared with the exact eigenergies in one specific example

A comparison study between sodium dodecyl sulfate and sodium dodecyl sulfonate with respect to the thermodynamic properties, micellization, and interaction with poly(ethylene glycol) in aqueous solutions

International Nuclear Information System (INIS)

Sadeghi, Rahmat; Shahabi, Somayyeh

2011-01-01

Graphical abstract: Apparent molar volume against molality: o, ·, and Δ, respectively in water, (1 and 4) wt% PEG solution at 293.15 K; x, Δ, and lozenge, respectively in water, (1 and 4) wt% PEG solution at 313.15 K. Research highlights: → C 12 H 25 SO 3 Na(SDSn) was seen to interact with PEG more weakly than C 12 H 25 SO 4 Na(SDS). → The constraints on molecular mobility of SDS micelles are larger than those of SDSn. → Entropy change on micellization for SDSn is larger than those for SDS. → Micelle formation of SDS is less endothermic and more spontaneous than that of SDSn. → Micelles of SDS have smaller aggregation number than that of SDSn. - Abstract: The density, sound velocity, and conductivity measurements were performed on aqueous solutions of sodium dodecyl sulfate (C 12 H 25 SO 4 Na) or sodium dodecyl sulfonate (C 12 H 25 SO 3 Na) in the absence and presence of poly(ethylene glycol) (PEG) at different temperatures. Changes in the apparent molar volumes and isentropic compressibilities upon micellization were derived using a pseudophase-transition approach and the infinite dilution apparent molar properties of the monomer and micellar form of C 12 H 25 SO 4 Na and C 12 H 25 SO 3 Na were determined. Variations of the critical micelle concentrations (CMCs) of both surfactants in the solutions investigated with temperature were obtained from which thermodynamic parameters of micellization were estimated. It was found that at low temperature the micelle formation process is endothermic and therefore, this process must be entropically driven. However, upon increasing the temperature, the enthalpic factor becomes more significant and, at temperatures higher than 303.15 K the micellization is enthalpy driven. The interactions between C 12 H 25 SO 4 Na/C 12 H 25 SO 3 Na and PEG were studied and it was found that sodium alkyl sulfonates were seen to interact more weakly than their sulfate analogues.

Preparation, structural, dielectric and magnetic properties of LaFeO3–PbTiO3 solid solutions

International Nuclear Information System (INIS)

Ivanov, S.A.; Tellgren, R.; Porcher, F.; Ericsson, T.; Mosunov, A.; Beran, P.; Korchagina, S.K.; Kumar, P. Anil; Mathieu, R.; Nordblad, P.

2012-01-01

Highlights: ► Solid-solutions of (1−x)LaFeO 3 –(x)PbTiO 3 were synthesized by solid-state reaction. ► XRPD and NPD evidence orthorhombic (x 0.8) crystal structures. ► LaFeO 3 -rich compositions order antiferromagnetically (x 3 -rich compositions exhibit ferroelectric order (x larger than 0.8). ► Magnetic and dielectric (relaxor) ordering coexist near room-temperature around x = 0.4. -- Abstract: Solid solutions of (1−x)LaFeO 3 –(x)PbTiO 3 (0 3+ cations in the B-site with propagation vector k = (0,0,0). Based on the obtained experimental data, a combined structural and magnetic phase diagram has been constructed. The factors governing the structural, dielectric and magnetic properties of (1−x)LaFeO 3 –(x)PbTiO 3 solid solutions are discussed, as well as their possible multiferroicity.

Influence of H/D isotope substitution on physicochemical properties of aqueous solutions of urea and thiourea

International Nuclear Information System (INIS)

Jelinska-Kazimierczuk, M.; Szydlowski, J.

2001-01-01

The influence of the H/D isotope substitution on excess volumes, partial molar volumes, viscosity and ultrasound speed in aqueous solutions of urea and thiourea are studied at 20 o C. The excess volume of the solutions studied is relatively small - however, it is negative in urea and positive in thiourea solutions. On the other hand, the deuteration affects the excess volume in both solutions in the same way: deuterated systems show smaller deviation from additivity than regular ones. The speed of sound in the systems studied increases monotonously with concentration , but its isotope effect decreases as the concentration increases. The curves of viscosity are monotonous too, but isotope effect of kinematic viscosity is practically the same in the whole concentration range studied. The present results for urea and thiourea aqueous solutions are compared with those previously obtained for amide- water systems. (author)

Dilute solution properties of canary seed (Phalaris canariensis) starch in comparison to wheat starch.

Science.gov (United States)

Irani, Mahdi; Razavi, Seyed M A; Abdel-Aal, El-Sayed M; Hucl, Pierre; Patterson, Carol Ann

2016-06-01

Dilute solution properties of an unknown starch are important to understand its performance and applications in food and non-food industries. In this paper, rheological and molecular properties (intrinsic viscosity, molecular weight, shape factor, voluminosity, conformation and coil overlap parameters) of the starches from two hairless canary seed varieties (CO5041 & CDC Maria) developed for food use were evaluated in the dilute regime (Starch dispersions in DMSO (0.5g/dl)) and compared with wheat starch (WS). The results showed that Higiro model is the best among five applied models for intrinsic viscosity determination of canary seed starch (CSS) and WS on the basis of coefficient of determination (R(2)) and root mean square error (RMSE). WS sample showed higher intrinsic viscosity value (1.670dl/g) in comparison to CSS samples (1.325-1.397dl/g). Berry number and the slope of master curve demonstrated that CSS and WS samples were in dilute domain without entanglement occurrence. The shape factor suggested spherical and ellipsoidal structure for CO5041 starch and ellipsoidal for CDC Maria starch and WS. The molecular weight, coil radius and coil volume of CSSs were smaller than WS. The behavior and molecular characterization of canary seed starch showed its unique properties compared with wheat starch. Copyright © 2016 Elsevier B.V. All rights reserved.

Timing Solution and Single-pulse Properties for Eight Rotating Radio Transients

Energy Technology Data Exchange (ETDEWEB)

Cui, B.-Y.; McLaughlin, M. A. [Department of Physics and Astronomy West Virginia University Morgantown, WV 26506 (United States); Boyles, J. [Department of Physics and Astronomy West Kentucky University Bowling Green, KY 42101 (United States); Palliyaguru, N. [Physics and Astronomy Department Texas Tech University Lubbock, TX 79409-1051 (United States)

2017-05-01

Rotating radio transients (RRATs), loosely defined as objects that are discovered through only their single pulses, are sporadic pulsars that have a wide range of emission properties. For many of them, we must measure their periods and determine timing solutions relying on the timing of their individual pulses, while some of the less sporadic RRATs can be timed by using folding techniques as we do for other pulsars. Here, based on Parkes and Green Bank Telescope (GBT) observations, we introduce our results on eight RRATs including their timing-derived rotation parameters, positions, and dispersion measures (DMs), along with a comparison of the spin-down properties of RRATs and normal pulsars. Using data for 24 RRATs, we find that their period derivatives are generally larger than those of normal pulsars, independent of any intrinsic correlation with period, indicating that RRATs’ highly sporadic emission may be associated with intrinsically larger magnetic fields. We carry out Lomb–Scargle tests to search for periodicities in RRATs’ pulse detection times with long timescales. Periodicities are detected for all targets, with significant candidates of roughly 3.4 hr for PSR J1623−0841 and 0.7 hr for PSR J1839−0141. We also analyze their single-pulse amplitude distributions, finding that log-normal distributions provide the best fits, as is the case for most pulsars. However, several RRATs exhibit power-law tails, as seen for pulsars emitting giant pulses. This, along with consideration of the selection effects against the detection of weak pulses, imply that RRAT pulses generally represent the tail of a normal intensity distribution.

Timing Solution and Single-pulse Properties for Eight Rotating Radio Transients

Science.gov (United States)

Cui, B.-Y.; Boyles, J.; McLaughlin, M. A.; Palliyaguru, N.

2017-05-01

Rotating radio transients (RRATs), loosely defined as objects that are discovered through only their single pulses, are sporadic pulsars that have a wide range of emission properties. For many of them, we must measure their periods and determine timing solutions relying on the timing of their individual pulses, while some of the less sporadic RRATs can be timed by using folding techniques as we do for other pulsars. Here, based on Parkes and Green Bank Telescope (GBT) observations, we introduce our results on eight RRATs including their timing-derived rotation parameters, positions, and dispersion measures (DMs), along with a comparison of the spin-down properties of RRATs and normal pulsars. Using data for 24 RRATs, we find that their period derivatives are generally larger than those of normal pulsars, independent of any intrinsic correlation with period, indicating that RRATs’ highly sporadic emission may be associated with intrinsically larger magnetic fields. We carry out Lomb-Scargle tests to search for periodicities in RRATs’ pulse detection times with long timescales. Periodicities are detected for all targets, with significant candidates of roughly 3.4 hr for PSR J1623-0841 and 0.7 hr for PSR J1839-0141. We also analyze their single-pulse amplitude distributions, finding that log-normal distributions provide the best fits, as is the case for most pulsars. However, several RRATs exhibit power-law tails, as seen for pulsars emitting giant pulses. This, along with consideration of the selection effects against the detection of weak pulses, imply that RRAT pulses generally represent the tail of a normal intensity distribution.

Classical solutions and extended supergravity

International Nuclear Information System (INIS)

de Alfaro, V.; Fubini, S.; Furlan, G.

1980-03-01

The existence and properties of classical solutions for gravity coupled to matter fields have been investigated previously with the limitation to conformally flat solutions. In the search for a guiding criterion to determine the form of the coupling among the fields, one is led to consider supersymmetric theories, and the question arises whether classical solutions persist in these models. It is found that a discrepancy persists between supergravity and standard meron solutions. Owing to the appearance of the scalar field, a new set of meron solutions exists for particular Lagrangian models. In conclusion, the form of solutions in Minkowski space is discussed

Meta-analysis of the effects of soil properties, site factors and experimental conditions on solute transport

Directory of Open Access Journals (Sweden)

J. K. Koestel

2012-06-01

Full Text Available Preferential flow is a widespread phenomenon that is known to strongly affect solute transport in soil, but our understanding and knowledge is still poor of the site factors and soil properties that promote it. To investigate these relationships, we assembled a database from the peer-reviewed literature containing information on 733 breakthrough curve experiments under steady-state flow conditions. Most of the collected experiments (585 of the 733 datasets had been conducted on undisturbed soil columns, although some experiments on repacked soil, clean sands, and glass beads were also included. In addition to the apparent dispersivity, we focused our attention on three indicators of preferential solute transport: namely the 5%-arrival time, the holdback factor, and the ratio of piston-flow and average transport velocities. Our results suggest that, in contrast to the 5%-arrival time and the holdback factor, the piston-flow to transport velocity ratio is not related to preferential macropore transport but rather to the exclusion or retardation of the applied tracer. Confirming that the apparent longitudinal dispersivity is positively correlated with the travel distance of the tracer, our results also illustrate that this relationship is refined if the normalized 5%-tracer arrival time is also taken into account. In particular, we found that the degree of preferential solute transport increases with apparent dispersivity and decreases with travel distance. A similar but weaker relationship was observed between apparent dispersivity, 5%-tracer arrival time, and lateral observation scale, such that the degree of preferential transport increases with lateral observation scale. However, we also found that the travel distance and the lateral observation scale in the investigated dataset are correlated, which makes it difficult to distinguish their influence on these transport characteristics. We also found that the strength of preferential transport

Magnetic and electrical properties of (FeIn2S4)1−x(CuIn5S8)x solid solutions

International Nuclear Information System (INIS)

Trukhanov, S.V.; Bodnar, I.V.; Zhafar, M.A.

2015-01-01

In this study, single crystals of FeIn 2 S 4 and CuIn 5 S 8 compounds, and (FeIn 2 S 4 ) 1−x (CuIn 5 S 8 ) x solid solutions were grown using the Bridgman method. The magnetic and electrical properties of the samples obtained were investigated at temperatures of 5–300 K and in a magnetic field range of 0–14 T. It was established that all of the solid solutions were paramagnets down to low temperatures of ~10 K. It was shown that the ground state of the magnetic phase of the samples was a spin glass state, where the freezing temperature increased monotonically with the increase in the concentration of Fe 2+ cations. All of the samples exhibited semiconductor characteristics in terms of electrical resistivity. The concentration-dependent critical magnetic temperatures, magnetic moment, and activation energy were plotted, which are probably explained by the magnetic state formation of the (FeIn 2 S 4 ) 1−x (CuIn 5 S 8 ) x solid solution single crystals based on the empirical Goodenough–Kanamori rules

Sorption of Pb2+ from Aqueous Solution unto Modified Rice Husk: Isotherms Studies

Directory of Open Access Journals (Sweden)

A. O. Dada

2013-01-01

Full Text Available Investigation of the sorption potential of rice husk, an agricultural waste, as an adsorbent was carried out. The rice husk was modified with orthophosphoric acid and was used for adsorption of lead (II ions (Pb2+ from aqueous solution. Physicochemical properties of the modified rice husk were determined. Equilibrium sorption data were confirmed with Langmuir, Freundlich and Temkin adsorption isotherms. On the basis of adsorption isotherm graphs, R2 values were determined to be 0.995, 0.916, and 0.797 for Langmuir, Temkin, and Freundlich isotherms, respectively, indicating that the data fitted well into the adsorption isotherms, but Langmuir isotherm is a better model. The maximum monolayer coverage from Langmuir studies, Qmax=138.89 mg/g, Langmuir isotherm constant, KL=0.699 L/mg, and the separation factor, RL=1.41×10−2 at 100 mg/L of lead(II ions indicating that the sorption process, was favourable. The suitability of modified rice husk as an adsorbent for the removal of lead ions from aqueous solution and its potential for pollution control is established.

Equilibriums of sorption of impurities of 3 d - cations by inorganic sorbents from phosphate and arsenate solutions

International Nuclear Information System (INIS)

Filatova, L.N.; Kurdyumova, T.N.; Bagrov, V.M.; Blyum, G.Z.

1986-01-01

Present article is devoted to equilibriums of sorption of impurities of 3 d - cations by inorganic sorbents from phosphate and arsenate solutions. Equilibriums of sorption of microquantities of iron, scandium, zink, copper, cobalt and manganese by inorganic sorbents on the basis of titanium and aluminium oxides from phosphate and arsenate solutions are studied. The influence of structural and chemical properties of matrix on sorption properties of oxides in phosphate and arsenate solutions is studied as well. It is defined that in concentrated solutions the sorption value of trace contaminant depends on a character of cation of alkaline metal.

Study of Asphaltene Solutions by Electrical Conductivity Measurements Conductivité électrique des solutions d'asphaltènes

Directory of Open Access Journals (Sweden)

Behar E.

2006-11-01

Full Text Available The asphaltene interactions in model solutions were studied using a technique based on the electrical conductivity measurement. Interactions with n-heptane, resins, surfactants, water, phenol and NaCI were investigated. The conclusions drawn from this study confirmed previous opinions on aggregation mechanism of asphaltenes in solutions. They confirmed also the interpretation of asphaltene behaviour in terms of colloidal solution theories. Les interactions des asphaltènes avec leur environnement moléculaire dans des solutions modèles ont été étudiées par la mesure de la conductivité électrique de ces solutions. Les interactions avec le n-heptane, des résines, des tensioactifs, l'eau, le phénol et le chlorure de sodium ont été explorées. Les conclusions tirées de cette étude ont confirmé certaines hypothèses faites sur les mécanismes d'agrégation des asphaltènes en solution, en particulier dans le cadre de la théorie des solutions colloïdales.

Corrosion Compatibility Studies on Inconel-600 in NP Decontamination Solution

Energy Technology Data Exchange (ETDEWEB)

Park, Sang Yoon; Jung, Jun Young; Won, Huijun; Choi, Wangkyu; Moon, Jeikwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-05-15

It is well known that corrosion and contamination process in the primary cooling circuit of nuclear reactors are essentially interrelated: the contaminant isotopes are mostly corrosion products activated in the reactor core, and the contamination takes place on the out-core of Inconel-600 surface. This radionuclide uptake takes place up to the inner oxide layer and oxide/metal interface. So, it is necessary to remove inner oxide layer as well as outer oxide layer for excellent decontamination effects. The outer oxide layers are composed of Fe{sub 3}O{sub 4} and NiFe{sub 2}O{sub 4}. On the other hand, the inner oxide layers are composed of Cr{sub 2}O{sub 3}, (Ni{sub 1-x}Ni{sub x})(Cr{sub 1-y}Fe{sub y}){sub 2}O{sub 4}, and FeCr{sub 2}O{sub 4}. Because of chromium in the trivalent oxidation state which is difficult to dissolve, the oxide layer has an excellent protectiveness and become hard to be decontaminated. Alkaline permanganate (AP) or nitric permanganate (NP) oxidative phase has been used to dissolve the chromium-rich oxide. A disadvantage of AP process is the generation of a large volume of secondary waste. On the other hand, that of NP process is the high corrosion rate for Ni-base alloys. Therefore, for the safe use of oxidative phase in PWR system decontamination, it is necessary to reformulate the NP chemicals for decrease of corrosion rate. This study describes the corrosion compatibility on Inconel-600 and type 304 stainless steel in NP decontamination solution for PWR applications. To evaluate the general corrosion properties, weight change of NP treated specimens was measured. NP treated specimen surface was observed using optical microscope (OM) and scanning electron microscopy (SEM) for the evaluation of the localized corrosion. The effect of additives on the corrosion of the specimens was also evaluated. This study describes the corrosion compatibility on Inconel-600 and type 304 stainless steel in NP decontamination solution for PWR applications

Corrosion Compatibility Studies on Inconel-600 in NP Decontamination Solution

International Nuclear Information System (INIS)

Park, Sang Yoon; Jung, Jun Young; Won, Huijun; Choi, Wangkyu; Moon, Jeikwon

2013-01-01

It is well known that corrosion and contamination process in the primary cooling circuit of nuclear reactors are essentially interrelated: the contaminant isotopes are mostly corrosion products activated in the reactor core, and the contamination takes place on the out-core of Inconel-600 surface. This radionuclide uptake takes place up to the inner oxide layer and oxide/metal interface. So, it is necessary to remove inner oxide layer as well as outer oxide layer for excellent decontamination effects. The outer oxide layers are composed of Fe 3 O 4 and NiFe 2 O 4 . On the other hand, the inner oxide layers are composed of Cr 2 O 3 , (Ni 1-x Ni x )(Cr 1-y Fe y ) 2 O 4 , and FeCr 2 O 4 . Because of chromium in the trivalent oxidation state which is difficult to dissolve, the oxide layer has an excellent protectiveness and become hard to be decontaminated. Alkaline permanganate (AP) or nitric permanganate (NP) oxidative phase has been used to dissolve the chromium-rich oxide. A disadvantage of AP process is the generation of a large volume of secondary waste. On the other hand, that of NP process is the high corrosion rate for Ni-base alloys. Therefore, for the safe use of oxidative phase in PWR system decontamination, it is necessary to reformulate the NP chemicals for decrease of corrosion rate. This study describes the corrosion compatibility on Inconel-600 and type 304 stainless steel in NP decontamination solution for PWR applications. To evaluate the general corrosion properties, weight change of NP treated specimens was measured. NP treated specimen surface was observed using optical microscope (OM) and scanning electron microscopy (SEM) for the evaluation of the localized corrosion. The effect of additives on the corrosion of the specimens was also evaluated. This study describes the corrosion compatibility on Inconel-600 and type 304 stainless steel in NP decontamination solution for PWR applications. It is revealed that Inconel-600 specimen is more

Physicochemical, bioactive, and sensory properties of persimmon-based ice cream: technique for order preference by similarity to ideal solution to determine optimum concentration.

Science.gov (United States)

Karaman, Safa; Toker, Ömer Said; Yüksel, Ferhat; Çam, Mustafa; Kayacier, Ahmed; Dogan, Mahmut

2014-01-01

In the present study, persimmon puree was incorporated into the ice cream mix at different concentrations (8, 16, 24, 32, and 40%) and some physicochemical (dry matter, ash, protein, pH, sugar, fat, mineral, color, and viscosity), textural (hardness, stickiness, and work of penetration), bioactive (antiradical activity and total phenolic content), and sensory properties of samples were investigated. The technique for order preference by similarity to ideal solution approach was used for the determination of optimum persimmon puree concentration based on the sensory and bioactive characteristics of final products. Increase in persimmon puree resulted in a decrease in the dry matter, ash, fat, protein contents, and viscosity of ice cream mix. Glucose, fructose, sucrose, and lactose were determined to be major sugars in the ice cream samples including persimmon and increase in persimmon puree concentration increased the fructose and glucose content. Better melting properties and textural characteristics were observed for the samples with the addition of persimmon. Magnesium, K, and Ca were determined to be major minerals in the samples and only K concentration increased with the increase in persimmon content. Bioactive properties of ice cream samples improved and, in general, acetone-water extracts showed higher bioactivity compared with ones obtained using methanol-water extracts. The technique for order preference by similarity to ideal solution approach showed that the most preferred sample was the ice cream containing 24% persimmon puree. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Studying Some of Electrical and Mechanical Properties for Kevlar Fiber Reinforced Epoxy

Science.gov (United States)

Rafeeq, Sewench N.; Hussein, Samah M.

2011-12-01

As ordinary known the ability of synthesizing electrical conducting polymer composites is possible but with poor mechanical properties, for the solution of this problem, we carried out this study in order to obtain that both properties. Three methods were applied for preparing the conductive polyaniline (PANI) composites using Kevlar fiber fabric as substrate for the deposition of the PANI at one time and the prepared composite (EP/Kevlar fiber) at others. The chemical oxidative method was adopted for polymerization of the aniline and simultaneously protonated of PANI with a hydrochloric acid at concentration (1M). Two kinds of oxidation agents (FeCl3.6H2O) and ((NH4)2S2O8) were used. The electrical measurements indicate the effect of each preparation method, kind of oxidant agent and the kind of mat erial which PANI deposited on the electrical results. The conductivity results showed that the prepared composites lie within semiconductors region. Temperature—dependence of electric conductivity results showed semiconductors and conductors behavior of this material within the applied temperature ranges. The mechan ical property (tensile strength) was studied. X-ray diffraction study showed the crystalline structure for EP/Kevlar fiber/PANI composites prepared by the three methods. These results gave optimism to the synthesis of conductive polymer composites with excellent mechanical properties..

Quantum chemical calculations and spectroscopic measurements of spectroscopic and thermodynamic properties of given uranyl complexes in aqueous solutions with possible environmental and industrial applications

Directory of Open Access Journals (Sweden)

Višňak Jakub

2016-01-01

Full Text Available A brief introduction into computational methodology and preliminary results for spectroscopic (excitation energies, vibrational frequencies in ground and excited electronic states and thermodynamic (stability constants, standard enthalpies and entropies of complexation reactions properties of some 1:1, 1:2 and 1:3 uranyl sulphato- and selenato- complexes in aqueos solutions will be given. The relativistic effects are included via Effective Core Potential (ECP, electron correlation via (TDDFT/B3LYP (dispersion interaction corrected and solvation is described via explicit inclusion of one hydration sphere beyond the coordinated water molecules. We acknowledge limits of this approximate description – more accurate calculations (ranging from semi-phenomenological two-component spin-orbit coupling up to four-component Dirac-Coulomb-Breit hamiltonian and Molecular Dynamics simulations are in preparation. The computational results are compared with the experimental results from Time-resolved Laser-induced Fluorescence Spectroscopy (TRLFS and UV-VIS spectroscopic studies (including our original experimental research on this topic. In case of the TRLFS and UV-VIS speciation studies, the problem of complex solution spectra decomposition into individual components is ill-conditioned and hints from theoretical chemistry could be very important. Qualitative agreement between our quantum chemical calculations of the spectroscopic properties and experimental data was achieved. Possible applications for geochemical modelling (e.g. safety studies of nuclear waste repositories, modelling of a future mining site and analytical chemical studies (including natural samples are discussed.

IR and NMR studies of hierarchical material obtained by the treatment of zeolite Y by ammonia solution

Science.gov (United States)

Gackowski, Mariusz; Kuterasiński, Łukasz; Podobiński, Jerzy; Sulikowski, Bogdan; Datka, Jerzy

2018-03-01

Ammonia treatment of ultrastable zeolite Y has a great impact on its features. XRD showed a partial loss of crystallinity coupled with a loss of long-distance zeolite ordering. However, a typical short-range zeolite ordering, in the light of 29Si NMR studies, was largely preserved. 27Al MAS NMR spectra evidenced that most of Al was located in zeolitic tetrahedral positions, but some of them adopted a distorted configuration. Evolution of zeolites acidity was followed quantitatively by using IR. In particular, such studies revealed the presence of strongly acidic Sisbnd OHsbnd Al groups. IR studies suggest also heterogeneity of these OH groups. The heterogeneity of Sisbnd OHsbnd Al groups was a consequence of the less ordered structure of zeolites treated with ammonia solutions. It was also found that the treatment with ammonia solutions yields hierarchical material. The samples revealed promising catalytic properties in the liquid phase isomerization of α-pinene. Zeolites desilicated with ammonia may constitute an inexpensive route yielding viable hierarchical catalysts.

Solution-printed organic semiconductor blends exhibiting transport properties on par with single crystals.

Science.gov (United States)

Niazi, Muhammad R; Li, Ruipeng; Qiang Li, Er; Kirmani, Ahmad R; Abdelsamie, Maged; Wang, Qingxiao; Pan, Wenyang; Payne, Marcia M; Anthony, John E; Smilgies, Detlef-M; Thoroddsen, Sigurdur T; Giannelis, Emmanuel P; Amassian, Aram

2015-11-23

Solution-printed organic semiconductors have emerged in recent years as promising contenders for roll-to-roll manufacturing of electronic and optoelectronic circuits. The stringent performance requirements for organic thin-film transistors (OTFTs) in terms of carrier mobility, switching speed, turn-on voltage and uniformity over large areas require performance currently achieved by organic single-crystal devices, but these suffer from scale-up challenges. Here we present a new method based on blade coating of a blend of conjugated small molecules and amorphous insulating polymers to produce OTFTs with consistently excellent performance characteristics (carrier mobility as high as 6.7 cm(2) V(-1) s(-1), low threshold voltages oforganic semiconductor films with transport properties and other figures of merit on par with their single-crystal counterparts.

Transition between vortex rings and MAP solutions for electrically charged magnetic solutions

Energy Technology Data Exchange (ETDEWEB)

Wong, Khai-Ming; Soltanian, Amin; Teh, Rosy [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia)

2014-03-05

We consider the bifurcation and transition of axially symmetric monopole-antimonopole pair (MAP) and vortex ring solutions in the presence of electric charge for the SU(2) Yang-Mills-Higgs field theory. Here we investigate the properties of MAP/vortex ring solutions with n = 3,η = 0.65, for different Higgs field strength λ. For λ < 4.93, there is only one fundamental branch of vortex ring solution, but at the critical value of λ{sub b} = 4.93, branching happens and 2 sets of new solutions appeared. The new branch with less energy is a full MAP solution while the branch with higher energy contains MAP at the beginning and separation between poles of MAP on the z-axis reduces gradually and at another critical value of λ{sub t} = 14.852, they merge together at z = 0. Beyond this point the solutions change to the vortex ring solutions and a transitions between MAP and vortex ring solutions happens at this branch.

Thermophysical Properties of Aqueous Solutions Used as Secondary Working Fluids

OpenAIRE

Melinder, Åke

2007-01-01

Secondary working fluids (secondary refrigerants, heat transfer fluids, antifreezes, brines) have long been used in various indirect re-frigeration and heat pump systems. Aqueous solutions (water solu-tions) have long been used as single phase (liquid only) secondary working fluids for cooling in supermarkets, ice rinks, heat recovery systems, heat pumps and other applications. However, aqueous solutions are increasingly used also for freezers in supermarkets and other applications in low tem...

Study of Bending Fatigue Properties of Al-Si Cast Alloy

Directory of Open Access Journals (Sweden)

Tillová E.

2017-09-01

Full Text Available Fatigue properties of casting Al-alloys are very sensitive to the microstructural features of the alloy (e.g. size and morphology of the eutectic Si, secondary dendrite arm spacing - SDAS, intermetallics, grain size and casting defects (porosity and oxides. Experimental study of bending fatigue properties of secondary cast alloys have shown that: fatigue tests up to 106-107cycles show mean fatigue limits of approx. 30-49 MPa (AlSi9Cu3 alloy - as cast state, approx. 65-76 MPa (AlSi9Cu3 alloy after solution treatment and 60-70 MPa (self-hardened AlZn10Si8Mg alloy in the tested casting condition; whenever large pore is present at or near the specimen’s surface, it will be the dominant cause of fatigue crack initiation; in the absence of large casting defects, the influence of microstructural features (Si morphology; Fe-rich phases on the fatigue performance becomes more pronounced.

Solute–Solute Interaction In α IRON: The Status QUO

Directory of Open Access Journals (Sweden)

Numakura H.

2015-09-01

Full Text Available An overview is presented on the interaction of substitutional solutes with carbon and nitrogen in α iron, which is an important factor in controlling the properties of steels. Starting from a simple model of trapping of the interstitial solute atoms by substitutional solute atoms, the principles of experimental methods for quantitative studies are described, focussing on the Snoek relaxation and solubility measurements, and the knowledge acquired by such experiments is reviewed. An account of recent theoretical approaches to the interaction is also given.

On Kasner solution in Bianchi I f( T) cosmology

Science.gov (United States)

Skugoreva, Maria A.; Toporensky, Alexey V.

2018-05-01

Recently the cosmological dynamics of an anisotropic Universe in f( T) gravity became an area of intense investigations. Some earlier papers devoted to this issue contain contradictory claims about the nature and propertied of vacuum solutions in this theory. The goal of the present paper is to clarify this situation. We compare properties of f( T) and f( R) vacuum solutions and outline differences between them. The Kasner solution appears to be an exact solution for the T=0 branch, and an asymptotic solution for the T ≠ 0 branch. It is shown that the Kasner solution is a past attractor if Tpast and future attractor for the T>0 branch.

Some Cavitation Properties of Liquids

Directory of Open Access Journals (Sweden)

K. D. Efremova

2016-01-01

Full Text Available Cavitation properties of liquid must be taken into consideration in the engineering design of hydraulic machines and hydro devices when there is a possibility that in their operation an absolute pressure in the liquid drops below atmospheric one, and for a certain time the liquid is in depression state. Cold boiling, which occurs at a comparatively low temperature under a reduced absolute pressure within or on the surface of the liquid is regarded as hydrostatic cavitation if the liquid is stationary or as hydrodynamic cavitation, if the liquid falls into conditions when in the flow cross-section there is a sharply increasing dynamic pressure and a dropping absolute pressure.In accordance with the theory of cavitation, the first phase of cavitation occurs when the absolute pressure of the degassed liquid drops to the saturated vapour pressure, and the air dissolved in the liquid, leaving the intermolecular space, is converted into micro-bubbles of combined air and becomes a generator of cavitation “nuclei”. A quantitative estimate of the minimum allowable absolute pressure in a real, fully or partially degassed liquid at which a hydrostatic cavitation occurs is of practical interest.Since the pressure of saturated vapour of a liquid is, to a certain extent, related to the forces of intermolecular interaction, it is necessary to have information on the cavitation properties of technical solutions, including air solution in a liquid, as a solute may weaken intermolecular bonds and affect the pressure value of the saturated solvent vapour. In the experiment to carry out vacuum degassing of liquids was used a hydraulic air driven vacuum pump.The paper presents hydrostatic and hydrodynamic degassing liquid processes used in the experiment.The experimental studies of the cavitation properties of technical liquids (sea and distilled water, saturated NaCl solution, and pure glycerol and as a 49/51% solution in water, mineral oil and jet fuel enabled

Improving the electrocatalytic properties of Pd-based catalyst for direct alcohol fuel cells: effect of solid solution.

Science.gov (United States)

Wen, Cuilian; Wei, Ying; Tang, Dian; Sa, Baisheng; Zhang, Teng; Chen, Changxin

2017-07-07

The tolerance of the electrode against the CO species absorbed upon the surface presents the biggest dilemma of the alcohol fuel cells. Here we report for the first time that the inclusion of (Zr, Ce)O 2 solid solution as the supporting material can significantly improve the anti-CO-poisoning as well as the activity of Pd/C catalyst for ethylene glycol electro-oxidation in KOH medium. In particular, the physical origin of the improved electrocatalytic properties has been unraveled by first principle calculations. The 3D stereoscopic Pd cluster on the surface of (Zr, Ce)O 2 solid solution leads to weaker Pd-C bonding and smaller CO desorption driving force. These results support that the Pd/ZrO 2 -CeO 2 /C composite catalyst could be used as a promising effective candidate for direct alcohol fuel cells application.

A study on the effect of solution heat treatment on the corrosion resistance of super duplex stainless steels

International Nuclear Information System (INIS)

Park, Jee Yong; Park, Yong Soo; Kim, Soon Tae

2001-01-01

High temperature solution heat treatment(typically higher than 1100 .deg. C) is known generally to reduces the resistance to localized corrosion on super duplex stainless. This is attributed to the formation of zone depleted of alloying elements. In this study, the corrosion properties were investigated on super duplex stainless steels with various solution heat treatments. The corrosion resistance of these steels was evaluated in terms of critical pitting temperature and cyclic potentiodynamic polarization test. Chemical composition of the austenite and ferrite phases were analyzed by SEM-EDS. The following results were obtained. (1) By conducting furnace cooling, critical pitting temperature and repassivation potential increased. (2) By omitting furnace cooling, solution heat treatment produced Cr and Mo depleted zone in the phase boundary. (3) During furnace cooling, Cr and Mo rediffused through the phase boundary. This increased the corrosion resistance of super duplex stainless steels

Influence of coal properties on mercury uptake from aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Lakatos, J.; Brown, S.D.; Snape, C.E. [Miskolc University, Miskolc-Egyetemvaros (Hungary). Research Inst. of Applied Chemistry

1999-10-01

The uptake of mercury (II) from aqueous solution by a range of coals has been studied and the results have been compared to those for a number of other sorbents, including commercial active carbons and cation-exchange resins. At pH 5 in a buffer medium, the capacities for mercury removal of the low-rank coals and the oxidized bituminous coals investigated are comparable to those of the other sorbents tested. For the lignites investigated, a high content of organic sulfur does not markedly affect the capacity for mercury uptake in relatively neutral and low chloride media, owing to redox reactions being the most likely mechanism involved. However, in highly acidic solutions, the capacities for mercury uptake are considerably greater for the high-sulfur coals investigated than for their low-sulfur counterparts due to chelation being the major sorption process involved. 36 refs., 4 figs., 7 tabs.

Computational studies of physical properties of Nb-Si based alloys

Energy Technology Data Exchange (ETDEWEB)

Ouyang, Lizhi [Middle Tennessee State Univ., Murfreesboro, TN (United States)

2015-04-16

The overall goal is to provide physical properties data supplementing experiments for thermodynamic modeling and other simulations such as phase filed simulation for microstructure and continuum simulations for mechanical properties. These predictive computational modeling and simulations may yield insights that can be used to guide materials design, processing, and manufacture. Ultimately, they may lead to usable Nb-Si based alloy which could play an important role in current plight towards greener energy. The main objectives of the proposed projects are: (1) developing a first principles method based supercell approach for calculating thermodynamic and mechanic properties of ordered crystals and disordered lattices including solid solution; (2) application of the supercell approach to Nb-Si base alloy to compute physical properties data that can be used for thermodynamic modeling and other simulations to guide the optimal design of Nb-Si based alloy.

Decoloration studies of some fluorescent dye solutions

International Nuclear Information System (INIS)

Zafar-uz-Zaman, M.; Ditta, A.

1997-01-01

Rhenium-186-(Sn)-l, l hydroxy ethylene diphosphonate (/sup 186/Re-HEDP) has been used for the palliation of metastatic bone pain. /sup 186/Re- has excellent physical properties that may be useful for the formulation of radiotherapeutic agents. It has a short half-life (90.6 hrs) with moderate energy particles (E /sub max/=1.07 MeV) that penetrate over a short range of tissue and gamma ray of 137 keV which is well suited to image. A number of samples of natural rhenium (metal) power were irradiated in PARR-I research reactor at a thermal neutrons flux of the order lx10/sup 14/ n.cm /sup -2/.s/sup -1/ for various time intervals in order to optimize the production yield of /sup 186/Re. The data indicated that 60 mCi/mg of radioactivity could be obtained for an irradiation time of 24 hours. The irradiated target was converted to its ammonium salt which was used for preparation of /sup 186/Re-HEDP complex. Labeling studies of dissolution salt of HEDP with /sup 186/Re were performed by varying the amounts of rhenium, HEDP and Sn. These studies were also carried out at different pH of the solutions. The quality control of /sup 186/Re-HEDP complex was checked by radio chromatographic techniques. These investigations indicated that the complex of optimum yield (approx. 95%) could be obtained by using amounts of Re (0.15 mg), HEDP (10 mg), stannous chloride dihydrate (4mg) and pH range of 4-6. The effect of antioxidant genetic acid was studied on the stability of the complex which was found to be stable up to five days in the presence of 3 mg of genetic acid. The biodistribution studies in rats showed optimum uptake by bone after 2.5 hours. (author)

Improving conditions for reuse of design solutions - by means of a context based solution library

DEFF Research Database (Denmark)

Mortensen, Niels Henrik; Grothe-Møller, Thorkild; Andreasen, Mogens Myrup

1997-01-01

Among the most important reasoning mechanisms in design is reasoning by analogy. One precondition for being able to reason about the properties and functionalitues of a product or subsystem is that the context of the solution is known. This paper presents a computer based solution library where...

Hydration patterns and salting effects in sodium chloride solution.

Science.gov (United States)

Li, Weifeng; Mu, Yuguang

2011-10-07

The salting effects of 2M sodium chloride electrolyte are studied based on a series of model solutes with properties ranging from hydrophobic to hydrophilic. Generally, hydrophobic solutes will be salted out and hydrophilic solutes will be salted in by NaCl solution. The solvation free energy changes are highly correlated with Kirkwood-Buff integrals. The underlying mechanism resorts to the preferential binding of ions and water to solutes. Our results demonstrate that the salting effect not only depends on the salt's position in Hofmeister series, but also on the solutes' specifics. Taking the hydration free energies of solutes and ions as independent variables, a schematic diagram of salting effects is suggested. The resolved multifaceted salting effects rely on the sensitive balance of the tripartite interaction among solutes, ions, and water. © 2011 American Institute of Physics

Study of some properties of partial differential equations by Lie algebra method

International Nuclear Information System (INIS)

Chongdar, A.K.; Ludu, A.

1990-05-01

In this note we present a system of optimal subalgebras of the Lie algebra obtained in course of investigating hypergeometric polynomial. In addition to this we have obtained some reduced equation and invariants of the P.D.E. obtained under certain transformation while studying hypergeometric polynomial by Weisner's method. Some topological properties of the solutions of P.D.E. are pointed out by using the extended jet bundle formalism. Some applications of our work on plasma physics and hydrodynamics are also cited. (author). 8 refs

Thermodynamic properties of ethanol solution of chiral camphors and its derivatives

Energy Technology Data Exchange (ETDEWEB)

Kimura, Takayoshi [Department of Chemistry, Kinki University, Kowakae, Higashi-Osaka 577-8502 (Japan)], E-mail: kimura@chem.kindai.ac.jp; Iwama, Sekai; Kido, Satoko; Khan, Mohammad Abdullah [Department of Chemistry, Kinki University, Kowakae, Higashi-Osaka 577-8502 (Japan)

2009-10-15

Enthalpies of mixing and the densities of ethanol solution of R- and S-enantiomers of camphor, 10-camphorsulfonamide, 10-camphorsulfonic acid, camphorquinone, and 10-camphorsulfonyl chloride have been measured for a wide range of mole fractions of heterochiral components at 298.15 K. Enthalpies of mixing were exothermic for all concentrations and heterochiral solutions were more stable than each of the homochiral solutions. Enthalpic stabilization of mixing of heterochiral solutions was increased with a decreasing concentration of all the camphor derivatives measured. The sequence of enthalpic stabilization on mixing was 10-camphorsulfonyl chloride, 10-camphorsulfonic acid, 10-camphorsulfonamide, camphor, and camphorquinone. Apparent molar volumes were determined and excess volumes of mixing of heterochiral solutions were small and negative. Enthalpic stabilizations were found to be dependent on dipole-dipole interaction between solutes and solvents.

Optical and rheological studies on weak gel-sol transition in aqueous solutions of poly(N-isopropylacrylamide-block-polystyrene

Directory of Open Access Journals (Sweden)

S. Sanjeevi Prasath

2017-07-01

Full Text Available The optical and rheological properties of aqueous solutions of block copolymer composed of low molecular weight poly(N-isopropylacrylamide-b-polystyrene are studied as a function of temperature. From light scattering measurements the block copolymer solution is found to form micelles at very low concentrations and the critical micellar concentration is identified as 0.005 wt%. Apart from the concentration dependence, a unique temperature dependent micelle formation is noted at 34 °C. Further, temperature dependent refractive index measurements shows that the refractive index increases with temperature (beyond the lower critical solution temperature, 31.6 °C of the polymer, and is attributed to the stable rearrangement of the proximal hydrophobic isopropyl-polystyrene chains in the collapsed polymer so as to overcome the steric hindrance effects offered by the hydrophobic chains. In the polymer concentrations investigated for rheological studies, the solution flows, yet manifested solid like behavior with G' > G" with the modulus being frequency dependent and the magnitude of G' two-fold higher than G" implying a weak gel state. Weak gel states are in general noted at high temperatures in most of the polymer systems, contrary to this, in our studies weak gel state is observed at lower temperature. Further, a transition from weak gel to sol state is observed at slightly elevated temperatures. The reason for the existence of weak gel state below the lower critical solution temperature is due to the micellar entanglements of poly(N-isopropylacrylamide-b-polystyrene with one another and whereas above the lower critical solution temperature disentanglement of the micelles makes the system behave like a viscoelastic liquid.

Exact solutions of the neutron slowing down equation

International Nuclear Information System (INIS)

Dawn, T.Y.; Yang, C.N.

1976-01-01

The problem of finding the exact analytic closed-form solution for the neutron slowing down equation in an infinite homogeneous medium is studied in some detail. The existence and unique properties of the solution of this equation for both the time-dependent and the time-independent cases are studied. A direct method is used to determine the solution of the stationary problem. The final result is given in terms of a sum of indefinite multiple integrals by which solutions of some special cases and the Placzek-type oscillation are examined. The same method can be applied to the time-dependent problem with the aid of the Laplace transformation technique, but the inverse transform is, in general, laborious. However, the solutions of two special cases are obtained explicitly. Results are compared with previously reported works in a variety of cases. The time moments for the positive integral n are evaluated, and the conditions for the existence of the negative moments are discussed

Solution processed pentacene thin films and their structural properties

International Nuclear Information System (INIS)

Tao Chunlan; Zhang Xuhui; Zhang Fujia; Liu Yiyang; Zhang Haoli

2007-01-01

The paper reported the solution process of pentacene thin films from organic solvent O-dichlorobenzene. The pentacene thin films obtained from different conditions were characterized by X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), and UV-vis spectroscopy. The result shows that the pentacene solution was successfully obtained at a minimum temperature of 40 deg. C. The optimum temperature of forming pentacene thin films was 100 deg. C

Thermophysical properties of ionic liquid, 1-hexyl-3-methylimidazolum bromide + N-N′bis(2-pyridylmethylidene)-1,2-diiminoethane (BPIE) Schiff base + N,N-dimethylformamide solutions

International Nuclear Information System (INIS)

Shekaari, Hemayat; Bezaatpour, Abolfazl; Khoshalhan, Maryam

2012-01-01

Highlights: ► Thermodynamic properties of ionic liquids + BPIE Schiff base + DMF were studied. ► There are preferential interactions between ionic liquid and BPIE molecules. ► The nonpolar–nonpolar interactions are dominant interactions between BPIE and ionic liquid. - Abstract: Effect of N-N′bis(2-pyridylmethylidene)-1,2-diiminoethane (BPIE) Schiff base on thermodynamic properties of ionic liquid, 1-hexyl-3-methylimidazolium bromide ([HMIm]Br) in N,N-dimethylformamide (DMF) solutions were determined at T = 298.15–313.15 K. The standard partial molar volumes, V φ 0 , partial molar volumes of transfer, Δ tr V φ 0 have been calculated using the measured density data. The cosphere overlap model was used to interpretate the partial molar volumes of transfer, Δ tr V φ 0 . The calculated Hepler's constants, ∂ 2 V φ 0 /∂ 2 T, indicate that the BPIE and ionic liquid have structure-breaking (chaotropic) tendency. Ion association constants, K a , and limiting molar conductivities, Λ 0 , viscosity B-coefficients and molar refractions, R D , have been used to confirm the conclusions obtained from the volumetric properties. The results were interpreted in terms of various solute–solvent interactions occuring in the investigated solutions and indicating an enhancement in the nonpolar–nonpolar interactions between the BPIE Schiff base and the ionic liquid with increasing BPIE concentration.

Physicochemical properties and radiolytic degradation studies on tri-iso-amyl phosphate (TiAP)

Energy Technology Data Exchange (ETDEWEB)

Sreenivasulu, B.; Sivaraman, Nagarajan [Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu (India). Homi Bhabha National Inst.; Suresh, A.; Rajeswari, S.; Ramanathan, N.; Antony, M.P.; Joseph, M. [Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu (India). Chemistry Group

2017-06-01

The solvent composed of tri-iso-amyl phosphate (TiAP) in n-dodecane (n-DD) is regarded as a promising candidate for reprocessing of spent fuel. In this context, the radiolytic degradation of a solution of TiAP in n-dodecane was investigated by irradiating the solvent to various absorbed dose levels of γ-radiation. The neat extractant or a solution of extractant in n-dodecane was irradiated in the presence of nitric acid. Physicochemical properties such as density, viscosity and interfacial tension (IFT) were measured for unirradiated and irradiated solutions. The extent of degradation was determined by measuring the variation in extraction behavior of U(VI) and Pu(IV) with irradiated solvent systems. Uranium and plutonium retention with irradiated solvents was also measured. The distribution ratio of uranium and plutonium increased with increase in absorbed dose. Effect of alpha degradation was studied by plutonium retention as a function of time using 1.1 M TiAP/n-DD. Laser desorption/ionization mass spectrometric technique was employed to identify the possible radiolytic degradation products. Similar studies were also carried out with tri-n-butyl phosphate (TBP) based solvent system under identical experimental conditions and the results are compared.

On the Construction and Properties of Weak Solutions Describing Dynamic Cavitation

KAUST Repository

Miroshnikov, Alexey

2014-08-21

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