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Sample records for alkaline salt solution

  1. Characterization of Laboratory Prepared Concrete Pastes Exposed to High Alkaline and High Sodium Salt Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-06-30

    The objective of this study was to identify potential chemical degradation mechanisms for the Saltstone Disposal Unit (SDU) concretes, which over the performance life of the structures may be exposed to highly alkaline sodium salt solutions containing sulfate, hydroxide, and other potentially corrosive chemicals in salt solution and saltstone flush water, drain water, leachate and / or pore solution. The samples analyzed in this study were cement pastes prepared in the SIMCO Technologies, Inc. concrete laboratory. They were based on the paste fractions of the concretes used to construct the Saltstone Disposal Units (SDUs). SDU 1 and 4 concrete pastes were represented by the PV1 test specimens. The paste in the SDU 2, 3, 5, and 6 concrete was represented by the PV2 test specimens. SIMCO Technologies, Inc. selected the chemicals and proportions in the aggressive solutions to approximate proportions in the saltstone pore solution [2, 3, 5, and 6]. These test specimens were cured for 56 days in curing chamber before being immersed in aggressive solutions. After exposure, the samples were frozen to prevent additional chemical transport and reaction. Selected archived (retrieved from the freezer) samples were sent to the Savannah River National Laboratory (SRNL) for additional characterization using x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x-ray (EDX) spectroscopy. Characterization results are summarized in this report. In addition, a correlation between the oxide composition of the pastes and their chemical durability in the alkaline salt solutions is provided.

  2. Elucidating how bamboo salt interacts with supported lipid membranes: influence of alkalinity on membrane fluidity.

    Science.gov (United States)

    Jeong, Jong Hee; Choi, Jae-Hyeok; Kim, Min Chul; Park, Jae Hyeon; Herrin, Jason Scott; Kim, Seung Hyun; Lee, Haiwon; Cho, Nam-Joon

    2015-07-01

    Bamboo salt is a traditional medicine produced from sea salt. It is widely used in Oriental medicine and is an alkalizing agent with reported antiinflammatory, antimicrobial and chemotherapeutic properties. Notwithstanding, linking specific molecular mechanisms with these properties has been challenging to establish in biological systems. In part, this issue may be related to bamboo salt eliciting nonspecific effects on components found within these systems. Herein, we investigated the effects of bamboo salt solution on supported lipid bilayers as a model system to characterize the interaction between lipid membranes and bamboo salt. The atomic composition of unprocessed and processed bamboo salts was first analyzed by mass spectrometry, and we identified several elements that have not been previously reported in other bamboo salt preparations. The alkalinity of hydrated samples was also measured and determined to be between pH 10 and 11 for bamboo salts. The effect of processed bamboo salt solutions on the fluidic properties of a supported lipid bilayer on glass was next investigated by fluorescence recovery after photobleaching (FRAP) analysis. It was demonstrated that, with increasing ionic strength of the bamboo salt solution, the fluidity of a lipid bilayer increased. On the contrary, increasing the ionic strength of near-neutral buffer solutions with sodium chloride salt diminished fluidity. To reconcile these two observations, we identified that solution alkalinity is critical for the effects of bamboo salt on membrane fluidity, as confirmed using three additional commercial bamboo salt preparations. Extended-DLVO model calculations support that the effects of bamboo salt on lipid membranes are due to the alkalinity imparting a stronger hydration force. Collectively, the results of this work demonstrate that processing of bamboo salt strongly affects its atomic composition and that the alkalinity of bamboo salt solutions contributes to its effect on membrane

  3. Physiological and Molecular Features of Puccinellia tenuiflora Tolerating Salt and Alkaline-Salt Stress

    Institute of Scientific and Technical Information of China (English)

    Xia Zhang; Liqin Wei; Zizhang Wang; Tai Wang

    2013-01-01

    Saline-alkali soil seriously threatens agriculture productivity; therefore,understanding the mechanism of plant tolerance to alkaline-salt stress has become a major challenge.Halophytic Puccinellia tenuiflora can tolerate salt and alkaline-salt stress,and is thus an ideal plant for studying this tolerance mechanism.In this study,we examined the salt and alkaline-salt stress tolerance of P.tenuiflora,and analyzed gene expression profiles under these stresses.Physiological experiments revealed that P.tenuiflora can grow normally with maximum stress under 600 mmol/L NaCl and 150 mmol/L Na2CO3 (pH 11.0)for 6 d.We identified 4,982 unigenes closely homologous to rice and barley.Furthermore,1,105 genes showed differentially expressed profiles under salt and alkaline-salt treatments.Differentially expressed genes were overrepresented in functions of photosynthesis,oxidation reduction,signal transduction,and transcription regulation.Almost all genes downregulated under salt and alkaline-salt stress were related to cell structure,photosynthesis,and protein synthesis.Comparing with salt stress,alkaline-salt stress triggered more differentially expressed genes and significantly upregulated genes related to H+ transport and citric acid synthesis.These data indicate common and diverse features of salt and alkalinesalt stress tolerance,and give novel insights into the molecular and physiological mechanisms of plant salt and alkaline-salt tolerance.

  4. Alkaline solution neutralization capacity of soil.

    Science.gov (United States)

    Asakura, Hiroshi; Sakanakura, Hirofumi; Matsuto, Toshihiko

    2010-10-01

    Alkaline eluate from municipal solid waste (MSW) incineration residue deposited in landfill alkalizes waste and soil layers. From the viewpoint of accelerating stability and preventing heavy metal elution, pH of the landfill layer (waste and daily cover soil) should be controlled. On the other hand, pH of leachate from existing MSW landfill sites is usually approximately neutral. One of the reasons is that daily cover soil can neutralize alkaline solution containing Ca(2+) as cation. However, in landfill layer where various types of wastes and reactions should be taken into consideration, the ability to neutralize alkaline solutions other than Ca(OH)(2) by soil should be evaluated. In this study, the neutralization capacities of various types of soils were measured using Ca(OH)(2) and NaOH solutions. Each soil used in this study showed approximately the same capacity to neutralize both alkaline solutions of Ca(OH)(2) and NaOH. The cation exchange capacity was less than 30% of the maximum alkali neutralization capacity obtained by the titration test. The mechanism of neutralization by the pH-dependent charge can explain the same neutralization capacities of the soils. Although further investigation on the neutralization capacity of the soils for alkaline substances other than NaOH is required, daily cover soil could serve as a buffer zone for alkaline leachates containing Ca(OH)(2) or other alkaline substances.

  5. Eco-physiological Characteristics of Alfalfa Seedlings in Response to Various Mixed Salt-alkaline Stresses

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Soil salinization and alkalization frequently co-occur in nature, but little is known about the mixed effects of salt-alkaline stresses on plants. An experiment with mixed salts (NaCl, Na2SO4, NaHCO3 and Na2CO3) and 30 salt-alkaline combinations(salinity 24-120 mmol/L and pH 7.03-10.32) treating Medicago sativa seedlings was conducted. The results demonstrated that salinity and alkalinity significantly affected total biomass and biomass components of seedlings. There were interactive effects of salt composition and concentration on biomass (P ≤ 0.001). The interactions between salinity and alkalinity stresses led to changes in the root activity along the salinity gradient (P ≤ 0.001). The effects of alkalinity on seedling survival rate were more significant than those of salinity, and the seedlings demonstrated some physiological responses(leaf electrolyte leakage rate and proline content) in order to adapt to mixed salt-alkaline stresses. It was concluded that the mixed salt-alkaline stresses, which differ from either salt or alkali stress, emphasize the significant interaction between salt concentration (salinity) and salt component (alkalinity). Further, the effects of the interaction between high alkalinity and salinity are more severe than those of either salt or alkali stress, and such a cooperative interaction results in more sensitive responses of ecological and physiological characteristics in plants.

  6. Coordination chemistry in fused-salt solutions

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    Gruen, D. M.

    1969-01-01

    Spectrophotometric work on structural determinations with fused-salt solutions is reviewed. Constraints placed on the method, as well as interpretation of the spectra, are discussed with parallels drawn to aqueous spectrophotometric curves of the same materials.

  7. Assimilation and Translocation of Dry Matter and Phosphorus in Rice Genotypes Affected by Salt-Alkaline Stress

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    Zhijie Tian

    2016-06-01

    Full Text Available Salt-alkaline stress generally leads to soil compaction and fertility decline. It also restricts rice growth and phosphorus acquisition. In this pot experiment, two relatively salt-alkaline tolerant (Dongdao-4 and Changbai-9 and sensitive (Changbai-25 and Tongyu-315 rice genotypes were planted in sandy (control and salt-alkaline soil to evaluate the characteristics of dry matter and phosphorus assimilation and translocation in rice. The results showed that dry matter and phosphorus assimilation in rice greatly decreased under salt-alkaline stress as the plants grew. The translocation and contribution of dry matter and phosphorus to the grains also increased markedly; different performances were observed between genotypes under salt-alkaline stress. D4 and C9 showed higher dry matter translocation, translocation efficiency and contribution of dry matter assimilation to panicles than those of C25 and T315. These changes in D4 and C9 indexes occurred at low levels of salt-alkaline treatment. Higher phosphorus acquisition efficiency of D4 and C9 were also found under salt-alkaline conditions. Additionally, the phosphorus translocation significantly decreased in C25 and T315 in the stress treatment. In conclusion, the results indicated that salt-alkaline-tolerant rice genotypes may have stronger abilities to assimilate and transfer biomass and phosphorus than sensitive genotypes, especially in salt-alkaline conditions.

  8. Scorpion toxins prefer salt solutions.

    Science.gov (United States)

    Nikouee, Azadeh; Khabiri, Morteza; Cwiklik, Lukasz

    2015-11-01

    There is a wide variety of ion channel types with various types of blockers, making research in this field very complicated. To reduce this complexity, it is essential to study ion channels and their blockers independently. Scorpion toxins, a major class of blockers, are charged short peptides with high affinities for potassium channels. Their high selectivity and inhibitory properties make them an important pharmacological tool for treating autoimmune or nervous system disorders. Scorpion toxins typically have highly charged surfaces and-like other proteins-an intrinsic ability to bind ions (Friedman J Phys Chem B 115(29):9213-9223, 1996; Baldwin Biophys J 71(4):2056-2063, 1996; Vrbka et al. Proc Natl Acad Sci USA 103(42):15440-15444, 2006a; Vrbka et al. J Phys Chem B 110(13):7036-43, 2006b). Thus, their effects on potassium channels are usually investigated in various ionic solutions. In this work, computer simulations of protein structures were performed to analyze the structural properties of the key residues (i.e., those that are presumably involved in contact with the surfaces of the ion channels) of 12 scorpion toxins. The presence of the two most physiologically abundant cations, Na(+) and K(+), was considered. The results indicated that the ion-binding properties of the toxin residues vary. Overall, all of the investigated toxins had more stable structures in ionic solutions than in water. We found that both the number and length of elements in the secondary structure varied depending on the ionic solution used (i.e., in the presence of NaCl or KCl). This study revealed that the ionic solution should be chosen carefully before performing experiments on these toxins. Similarly, the influence of these ions should be taken into consideration in the design of toxin-based pharmaceuticals.

  9. Mechanism of gold dissolving in alkaline thiourea solution

    Institute of Scientific and Technical Information of China (English)

    CHAI Li-yuan; WANG Yun-yan

    2007-01-01

    Reaction mechanism of gold dissolving in alkaline thiourea solution was studied by electrochemical methods, such as cyclic voltammetry, chronopotentiometry, AC impedance, linear sweep voltammetry. Apparent activation energy of anodic process of gold electrode dissolving in alkaline thiourea solution is 14.91 kJ/mol. Rate determining step is the process of gold thiourea complex diffusing away from electrode surface to solution. The results of AC impedance and chronopotentiometry indicate that thiourea adsorbs on gold electrode surface before dissolving in solution. There does not exist proceeding chemical reactions. Formamidine disulfide, the decomposed product of thiourea, does not participate the process of gold dissolution and thiourea complex. Species with electro-activity produced in the process of electrode reaction adsorbs on the electrode surface. In alkaline thiourea solution, gold dissolving mechanism undergoes the following courses: adsorption of thiourea on electrode surface; charge transfer from gold atom to thiourea molecule; Au[SC(NH2)2]ads+ receiving a thiourea molecule and forming stable Au[SC(NH2)2]2+; and then Au[SC(NH2)2]2+diffusing away from the electrode surface to solution, the last step is the rate-determining one.

  10. Salt-specific effects in lysozyme solutions

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    T. Janc

    2016-03-01

    Full Text Available The effects of additions of low-molecular-mass salts on the properties of aqueous lysozyme solutions are examined by using the cloud-point temperature, T_{cloud}, measurements. Mixtures of protein, buffer, and simple salt in water are studied at pH=6.8 (phosphate buffer and pH=4.6 (acetate buffer. We show that an addition of buffer in the amount above I_{buffer} = 0.6 mol dm^{-3} does not affect the T_{cloud} values. However, by replacing a certain amount of the buffer electrolyte by another salt, keeping the total ionic strength constant, we can significantly change the cloud-point temperature. All the salts de-stabilize the solution and the magnitude of the effect depends on the nature of the salt. Experimental results are analyzed within the framework of the one-component model, which treats the protein-protein interaction as highly directional and of short-range. We use this approach to predict the second virial coefficients, and liquid-liquid phase diagrams under conditions, where T_{cloud} is determined experimentally.

  11. A new electrochemical oscillatory system of bromate in alkaline solution

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new electrochemical oscillatory system of bromate in alkaline solution is reported. In PtBromate-Alkaline solution system, two different types of electrochemical oscillations (Type Ⅰ and Type Ⅱ) can be observed. Type Ⅰ appears before hydrogen evolution and Type Ⅱ involves periodic hydrogen evolution. Type Ⅰ relates to the adsorption/desorption of the hydrogen on platinum electrode, and Type Ⅱ with periodic oscillation stems from the coupling of electrochemical reactions (the reduction of bromate and evolution hydrogen reaction) with mass transfer (diffusion and convection). More over, under the right conditions, the two types appear in different oscillatory modes, for example,simple periodical mode and mixed one, etc,, Crossed cycle in the cyclic voltammograms, which is the basiccharacteristics for electrochemical oscillatory systems, has also been observed as expected.

  12. Solubilisation of lignite during oxydesulphurization in alkaline solutions

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    Yaman, S.; Kuecuekbayrak, S. [Istanbul Technical Univ., Chemical Engineering Dept. (Turkey)

    1997-12-31

    Some desulphurization processes such as oxydesulphurization in which dissolved oxygen is attached to coal particles are performed usually in alkaline solutions. Therefore, these processes are resulted in not only sulphur removal but also some solubilisation of the coal matrix. In this study three different Turkish lignite samples are subjected to various oxydesulphurization processes in which dilute solutions of NaOH, Na{sub 2}CO{sub 3}, NH{sub 4}OH or Na{sub 2}B{sub 4}O{sub 7} containing dissolved oxygen under pressure were applied. The experiments were performed in a magnetically stirred and electrically heated Parr autoclave. The extent of the solubilisation is varied depending on the type and concentration of the alkaline used, the applied temperature and the rank of the lignite sample used. (orig.)

  13. THE KINETICS OF SAPONIFICATION OF IODOACETIC ACID BY SODIUM HYDROXIDE AND BY CERTAIN ALKALINE BUFFER SOLUTIONS.

    Science.gov (United States)

    Brdicka, R

    1936-07-20

    1. The rate of the saponification of iodoacetic acid in sodium hydroxide and alkaline buffer solutions yielding glycollic acid was measured by means of Heyrovský's polarographic method. 2. From the bimolecular velocity constants, increasing with the ionic strength of the solution, the Brönsted factor, F, which characterizes the primary salt effect, was calculated. 3. In the borate buffer solutions the monomolecular constants of the saponification were determined which, at values above the pH of neutralization of boric acid, show a proportionality to the concentration of hydroxyl anions. Below the pH of neutralization of boric acid, they are proportional to the concentration of borate anions.

  14. SOLUTION MINING IN SALT DOMES OF THE GULF COAST EMBAYMENT

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    Griswold, G. B.

    1981-02-01

    Following a description of salt resources in the salt domes of the gulf coast embayment, mining, particularly solution mining, is described. A scenario is constructed which could lead to release of radioactive waste stored in a salt dome via inadvertent solution mining and the consequences of this scenario are analyzed.

  15. Identification of a major QTL allele from wild soybean (Glycine soja Sieb. & Zucc.) for increasing alkaline salt tolerance in soybean.

    Science.gov (United States)

    Tuyen, D D; Lal, S K; Xu, D H

    2010-07-01

    Salt-affected soils are generally classified into two main categories, sodic (alkaline) and saline. Our previous studies showed that the wild soybean accession JWS156-1 (Glycine soja) from the Kinki area of Japan was tolerant to NaCl salt, and the quantitative trait locus (QTL) for NaCl salt tolerance was located on soybean linkage group N (chromosome 3). Further investigation revealed that the wild soybean accession JWS156-1 also had a higher tolerance to alkaline salt stress. In the present study, an F(6) recombinant inbred line mapping population (n = 112) and an F(2) population (n = 149) derived from crosses between a cultivated soybean cultivar Jackson and JWS156-1 were used to identify QTL for alkaline salt tolerance in soybean. Evaluation of soybean alkaline salt tolerance was carried out based on salt tolerance rating (STR) and leaf chlorophyll content (SPAD value) after treatment with 180 mM NaHCO(3) for about 3 weeks under greenhouse conditions. In both populations, a significant QTL for alkaline salt tolerance was detected on the molecular linkage group D2 (chromosome 17), which accounted for 50.2 and 13.0% of the total variation for STR in the F(6) and the F(2) populations, respectively. The wild soybean contributed to the tolerance allele in the progenies. Our results suggest that QTL for alkaline salt tolerance is different from the QTL for NaCl salt tolerance found previously in this wild soybean genotype. The DNA markers closely associated with the QTLs might be useful for marker-assisted selection to pyramid tolerance genes in soybean for both alkaline and saline stresses.

  16. Apparent Dissolution Kinetics of Diatomite in Alkaline Solution

    Institute of Scientific and Technical Information of China (English)

    DU Gaoxiang; L(U) Guocheng; HE Xuwen

    2013-01-01

    The dissolution kinetics of diatomite in alkaline solution is the theoretical basis for the process optimization of alkali-diatomite reaction and its applications.In this study,the dissolution kinetics of diatomite in NaOH solution is investigated.The results indicate that the dissolution reaction fits well the unreacted shrinking core model for solid-liquid heterogeneous reactions.The apparent reaction order for NaOH is 2 and the apparent activation energy for the reaction (Ea) is 28.06 kJ.mol-1.The intra-particle diffusion through the sodium silicate layer is the rate-controlling step.When the dissolution reaction occurs at the interface of unreacted diatomite solid core,the diffusion in the trans-layer (the liquid film around the wetted particle) reduces the rate of whole dissolution process.

  17. SOLUTIONS TO ECOLOGICAL RECONSTRUCTION OF SALT LANDS

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    Elena Constantin

    2010-01-01

    Full Text Available The paper presents improvement solutions for the ecological reconstruction of salt land according to the characteristicsof their natural conditions. Agroameliorative, agrobiological, agrochemical and hydroameliorative methods may beused. Effectiveness of ecological restoration increases by applying complex ameliorative works. The main role of suchan undreground drainage facility is to collect the salt-loaded, leaching water. Drain distance is calculated for nonpermanentflow conditions, establishing a distance L that allows the lowering grounwater level from its highesthydraulic load to its best value, ht, withing a given time length. The sewer canals should have a depth of min. 1.2 if theland is not equipped with underground drains, and between 1.5 and 1.6 if underground drainage exists.The distancebetween the antenna and the sewer canal should be about 200 m or the length of the watering installation. Verticaldrainage consists in the use of wells with a depth of 25 m, equipped with selected gravel filter (Ø 2-7 mm and adecanter (1.5 m in length.

  18. Cu(II) complex formation with xylitol in alkaline solutions.

    Science.gov (United States)

    Norkus, Eugenijus; Vaiciūniene, Jūrate; Vuorinen, Tapani; Gaidamauskas, Ernestas; Reklaitis, Jonas; Jääskeläinen, Anna-Stiina; Crans, Debbie C

    2004-02-25

    The formation of four Cu(II)-xylitol complexes was observed in aqueous alkaline solutions (11.0 or =10), whereas dinuclear complex Cu2Xyl (log beta=29.2 +/- 0.3) is the predominant species at low ligand-to-metal ratio (L:M=0.5). Diffusion coefficients and molar absorptivities of the complex species were determined. pH variable 13C NMR suggested that pKa values of xylitol are rather similar and equal to 13.8 +/- 0.2, 13.9 +/- 0.1 and 13.9 +/- 0.2 for OH-groups adjacent to (C-1,C-5), (C-3) and (C-2,C-4) carbon atoms, respectively.

  19. Electrochemical kinetics of gold dissolving in alkaline thiourea solution

    Institute of Scientific and Technical Information of China (English)

    CHAI Li-yuan; WANG Yun-yan

    2006-01-01

    Kinetic parameters of the electrode reactions were measured by investigating steady-state current-potential behaviors. The results show that the apparent transfer coefficient of anodic process is 0.058 2, diffusion coefficient of thiourea gold complex is 6.04 × 10-6 cm2/s,anodic reaction order of thiourea is 2. 018 3, and anodic reaction order of OH- is 0. 016 6. The theoretical kinetics equation of gold dissolving in alkaline thiourea solution is deduced,which indicates that anodic reaction order of thiourea is 2, and anodic reaction order of OH- is 0. The theoretical values of the kinetic parameters are consistent with experimental values very well. The correctness of the mechanism is further demonstrated using apparent transfer coefficient according to the electrochemical dynamic equation of multi-electron reaction.

  20. Ion aggregation in high salt solutions. III. Computational vibrational spectroscopy of HDO in aqueous salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jun-Ho; Lim, Sohee; Chon, Bonghwan; Cho, Minhaeng, E-mail: mcho@korea.ac.kr [Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Seoul 136-713 (Korea, Republic of); Department of Chemistry, Korea University, Seoul 136-713 (Korea, Republic of); Kim, Heejae; Kim, Seongheun [Department of Chemistry, Korea University, Seoul 136-713 (Korea, Republic of)

    2015-05-28

    The vibrational frequency, frequency fluctuation dynamics, and transition dipole moment of the O—D stretch mode of HDO molecule in aqueous solutions are strongly dependent on its local electrostatic environment and hydrogen-bond network structure. Therefore, the time-resolved vibrational spectroscopy the O—D stretch mode has been particularly used to investigate specific ion effects on water structure. Despite prolonged efforts to understand the interplay of O—D vibrational dynamics with local water hydrogen-bond network and ion aggregate structures in high salt solutions, still there exists a gap between theory and experiment due to a lack of quantitative model for accurately describing O—D stretch frequency in high salt solutions. To fill this gap, we have performed numerical simulations of Raman scattering and IR absorption spectra of the O—D stretch mode of HDO in highly concentrated NaCl and KSCN solutions and compared them with experimental results. Carrying out extensive quantum chemistry calculations on not only water clusters but also ion-water clusters, we first developed a distributed vibrational solvatochromic charge model for the O—D stretch mode in aqueous salt solutions. Furthermore, the non-Condon effect on the vibrational transition dipole moment of the O—D stretch mode was fully taken into consideration with the charge response kernel that is non-local polarizability density. From the fluctuating O—D stretch mode frequencies and transition dipole vectors obtained from the molecular dynamics simulations, the O—D stretch Raman scattering and IR absorption spectra of HDO in salt solutions could be calculated. The polarization effect on the transition dipole vector of the O—D stretch mode is shown to be important and the asymmetric line shapes of the O—D stretch Raman scattering and IR absorption spectra of HDO especially in highly concentrated NaCl and KSCN solutions are in quantitative agreement with experimental results. We

  1. Marinade with alkaline solutions for the improvement of pork quality

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    Viviane Maria Oliveira dos Santos

    2012-11-01

    Full Text Available The objective of this work was to evaluate the effects of alkaline solution marinades on the characteristics of pork subjected to post-mortem pH decrease in pig muscle. The pH of carcasses was measured in a commercial slaughterhouse (n = 526, 45 min after slaughtering (pH45 and, then, the carcasses were divided into the groups with pH455.7. Ten samples of the longissimus dorsi muscles of each group were collected and distributed in an entirely randomized design, in a 2x4 factorial arrangement, with two conditions (pH455.7, and four marinade solutions: TC, no marinade; TM1, sodium bicarbonate and sodium chloride; TM2, sodium tripolyphosphate and sodium chloride; TM3, sodium bicarbonate, sodium tripolyphosphate and sodium chloride. There was no interaction between pH45 of the meat and the marinade treatments. Meat with pH45<5.7 showed higher values for lightness, and for purge loss (PL, exudate loss (EL, cooking loss (CL and shear force (SF. Marinating increased the pH, reduced the lightness, EL, CL and SF, and improved tenderness, juiciness and flavor of meat. Marinades with solutions containing chloride, bicarbonate, and sodium tripolyphosphate are effective in the improvement of pork quality, making physical characteristics of marinated meat similar to those of fresh pork, as a consequence of accelerated postmortem glycolysis.

  2. The solubility of toluene in aqueous salt solutions.

    Science.gov (United States)

    Poulson, S; Harrington, R; Drever, J

    1999-03-01

    The solubility of toluene has been measured in distilled water, and in various inorganic salt solutions. Values of the Setschenow constant, K(S), which quantify toluene solubility versus salt concentration, have been determined for each salt. Values of K(S) are compared to the activity of water for the salt solutions. Data from this study, consistent with earlier data, suggests that the effects of salts upon toluene solubility are non-additive. This contrasts the additive behavior of inorganic salts upon the solubility of nonpolar organic compounds, such as benzene and naphthalene, reported in the literature. Specific interaction between slightly polar toluene and ions in solution is suggested as a possible explanation for the non-additive effect of salts on the solubility of toluene.

  3. Catalytic actions of alkaline salts in reactions between 1,2,3,4-butanetetracarboxylic acid and cellulose: II. Esterification.

    Science.gov (United States)

    Ji, Bolin; Tang, Peixin; Yan, Kelu; Sun, Gang

    2015-11-05

    1,2,3,4-Butanetetracarboxylic acid (BTCA) reacts with cellulose in two steps with catalysis of alkaline salts such as sodium hypophosphite: anhydride formation and esterification of anhydride with cellulose. The alkali metal ions were found effective in catalyzing formation of BTCA anhydride in a previous report. In this work, catalytic functions of the alkaline salts in the esterification reaction between BTCA anhydride and cellulose were investigated. Results revealed that acid anions play an important role in the esterification reaction by assisting removal of protons on intermediates and completion of the esterification between cellulose and BTCA. Besides, alkaline salts with lower pKa1 values of the corresponding acids are more effective ones for the reaction since addition of these salts could lead to lower pH values and higher acid anion concentrations in finishing baths. The mechanism explains the results of FTIR and wrinkle recovery angles of the fabrics cured under different temperatures and times.

  4. Salt Effect on Osmotic Pressure of Polyelectrolyte Solutions: Simulation Study

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    Jan-Michael Y. Carrillo

    2014-07-01

    Full Text Available Abstract: We present results of the hybrid Monte Carlo/molecular dynamics simulations of the osmotic pressure of salt solutions of polyelectrolytes. In our simulations, we used a coarse-grained representation of polyelectrolyte chains, counterions and salt ions. During simulation runs, we alternate Monte Carlo and molecular dynamics simulation steps. Monte Carlo steps were used to perform small ion exchange between simulation box containing salt ions (salt reservoir and simulation box with polyelectrolyte chains, counterions and salt ions (polyelectrolyte solution. This allowed us to model Donnan equilibrium and partitioning of salt and counterions across membrane impermeable to polyelectrolyte chains. Our simulations have shown that the main contribution to the system osmotic pressure is due to salt ions and osmotically active counterions. The fraction of the condensed (osmotically inactive counterions first increases with decreases in the solution ionic strength then it saturates. The reduced value of the system osmotic coefficient is a universal function of the ratio of the concentration of osmotically active counterions and salt concentration in salt reservoir. Simulation results are in a very good agreement with osmotic pressure measurements in sodium polystyrene sulfonate, DNA, polyacrylic acid, sodium polyanetholesulfonic acid, polyvinylbenzoic acid, and polydiallyldimethylammonium chloride solutions.

  5. [Structure and Activity of Fungal Lipases in Bile Salt Solutions].

    Science.gov (United States)

    Bogdanova, L R; Bakirova, D R; Valiullina, Yu A; Idiyatullin, B Z; Faizullin, D A; Zueva, O S; Zuev, Yu F

    2016-01-01

    The changes in structure and catalytic properties of fungal lipases (Candida rugosa, Rhizomucor miehei, Mucor javanicus) were investigated in micellar solutions of bile salts that differ in hydrophilic-lypophilic balance and reaction medium properties. The methods of circular dichroism and tryptophan fluorescence were applied to estimate the changes in peptide structure within complexes with bile salt micelles. Bile salts do not exert a significant influence on the structure of the enzymes under study: in Rh. miehei and M. javanicus lipases the alpha helix content slightly decreased, the influence of bile salts on the C. rugosa structure was not revealed. Despite negligible structural modifications in the enzymes, in bile salt solutions a considerable change in their catalytic properties was observed: an abrupt decrease in catalytic effectiveness. Substrate-bile salts micelles complex formation was demonstrated by the NMR self-diffusion method. The model of a regulation of fungal lipase activity was proposed.

  6. Forces between Hydrophobic Solids in Concentrated Aqueous Salt Solution

    OpenAIRE

    Mastropietro, Dean J; Ducker, William A.

    2012-01-01

    Much research has focused on the discovery and description of long-ranged forces between hydrophobic solids immersed in water. Here we show that the force between high contact-angle solids in concentrated salt solution (1 M KCl) agrees very well with van der Waals forces calculated from Lifshitz theory for separations greater than 5 nm. The hydrophobic solids are octadecyltrichlorosilane-coated glass, with an advancing contact angle of 108 degrees. Thus, in 1 M salt solution, it is unnecessar...

  7. Solution-derived sodalite made with Si- and Ge-ethoxide precursors for immobilizing electrorefiner salt

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Brian J.; Lepry, William C.; Crum, Jarrod V.

    2016-01-01

    Chlorosodalite has the general form of Na8(AlSiO4)6Cl2 and this paper describes experiments conducted to synthesize sodalite to immobilize a mixed chloride salt using solution-based techniques. Sodalites were made using different Group IV contributions from either Si(OC2H5)4 or Ge(OC2H5)4, NaAlO2, and a simulated spent electrorefiner salt solution containing a mixture of alkali, alkaline earth, and lanthanide chlorides. Additionally, 6 glass binders at low loadings of 5 mass% were evaluated as sintering aids for the consolidation process. The approach of using the organic Group IV additives can be used to produce large quantities of sodalite at room temperature and shows promise over a method where colloidal silica is used as the silica source. However, the small particle sizes inhibited densification during pressure-less sintering.

  8. Behavior of gellan in aqueous-salt solutions and oilfield saline water

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    Zhanar Nurakhmetova

    2015-09-01

    Full Text Available The influence of storage time and temperature on the behavior of low acyl gellan (LAG was studied by viscometry and 1H NMR spectroscopy without salt addition. The viscometric results revealed that the effectiveness of salts to enhance gelation of gellan changes in the following order: BaСl2>CaCl2»MgCl2>KCl>NaCl. The sol-gel and liquid-solid phase transitions of gellan solutions were observed upon addition of oilfield water containing 73 g L-1 of alkaline and alkaline earth metal ions. The effectiveness of salts to induce the separation of liquid and solid phases changes in the sequence: NaCl>KCl>MgCl2»CaCl2»BaСl2. The hydrodynamic behavior of 0.5 wt.% gellan solution injected into the sand pack model with high (20 Darcy and lower (2 Darcy permeability is useful to model the oil reservoirs in the process of enhanced oil recovery.

  9. Decomposition Studies of Triphenylboron, Diphenylborinic Acid and Phenylboric Acid in Aqueous Alkaline Solutions Containing Copper

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C.L. [Westinghouse Savannah River Company, AIKEN, SC (United States); Peterson, R. A.

    1997-02-11

    This report documents the copper-catalyzed chemical kinetics of triphenylboron, diphenylborinic acid and phenylboric acid (3PB, 2PB and PBA) in aqueous alkaline solution contained in carbon-steel vessels between 40 and 70 degrees C.

  10. Development of alkaline solution separations for potential partitioning of used nuclear fuels

    Energy Technology Data Exchange (ETDEWEB)

    Jarvinen, Gordon D [Los Alamos National Laboratory; Runde, Wolfgang H [Los Alamos National Laboratory; Goff, George S [Los Alamos National Laboratory

    2009-01-01

    The processing of used nuclear fuel in alkaline solution provides potentially useful new selectivity for separating the actinides from each other and f rom the fission products. Over the ast decade, several research teams around the world have considered dissolution of used fuel in alkaline solution and further partitioning in this medium as an alternative to acid dissolution. The chemistry of the actinides and fission products in alkaline soilltion requires extensive investigation to more carefully evaluate its potential for developing useful separation methods for used nuclear fueI.

  11. Molecular Thermodynamic Model for Polyelectrolyte Solutions with Added Salts

    Institute of Scientific and Technical Information of China (English)

    ZHANGBo; CAIJun; 等

    2002-01-01

    A molecular thermodynamic model of polyelectrolyte developed previously was extended to polyelectrolyte solutions with added salts.Thermodynamic properties,such as activity coefficients of polyelectrolytes or added salts and osmotic coefficients of solvent, of a number of aqueous mixtures of polyelectrolytes and salts are analyzed with the proposed model.Successful correlation is obtained in the range of moderate or higher polyion concentration.For the same sample,thermodynamic properties of polyelectrolytes with and without simple electrolytes can be predicted mutually using parameters from regression data.

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

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Tae Soo; Koh, Jung Jae; Han, Haesook [Department of Chemistry, University of Nevada at Las Vegas, 4505 Maryland Parkway, Box 454003, Las Vegas, NV 89154 (United States); Bhowmik, Pradip K., E-mail: pradip.bhowmik@unlv.edu [Department of Chemistry, University of Nevada at Las Vegas, 4505 Maryland Parkway, Box 454003, Las Vegas, NV 89154 (United States)

    2013-05-15

    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 {sup 1}H, {sup 19}F, and {sup 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.

  13. Forces between hydrophobic solids in concentrated aqueous salt solution.

    Science.gov (United States)

    Mastropietro, Dean J; Ducker, William A

    2012-03-09

    Much research has focused on the discovery and description of long-ranged forces between hydrophobic solids immersed in water. Here we show that the force between high contact-angle solids in concentrated salt solution (1 M KCl) agrees very well with van der Waals forces calculated from Lifshitz theory for separations greater than 5 nm. The hydrophobic solids are octadecyltrichlorosilane-coated glass, with an advancing contact angle of 108°. Thus, in 1 M salt solution, it is unnecessary to invoke the presence of a hydrophobic force at separations greater than 5 nm. Through measurement in salt solution, we avoid the necessity of accounting for large electrostatic forces that frequently occur in pure water and may obscure resolution of other forces.

  14. Syntheses, structure and properties of Alkaline-earth metal salts of 4-Nitrophenylacetic acid

    Indian Academy of Sciences (India)

    BIKSHANDARKOIL R SRINIVASAN; KIRAN T DHAVSKAR; CHRISTIAN NÄTHER

    2016-11-01

    The synthesis, crystal structure, spectral characteristics and thermal properties of alkaline-earth metal salts of 4-nitrophenylacetic acid (4-npaH) namely, [Mg(H₂O)₆](4-npa)₂·4H₂O (4-npa = 4-nitrophenylacetate) (1), [Ca(H₂O)₂(4-npa)₂] (2) and [Sr(H₂O)₃(4-npa)₂]·4.5H₂O(3) are reported. In 1, the 4-npa ion functions as a charge balancing counter anion for the octahedral [Mg(H₂O)6]²⁺ unit with the Mg(II) ion situated on a centre of inversion. The two unique lattice water molecules link the [Mg(H₂O)₆]²⁺ cations and 4-npa anions with the aid of O-H· · ·O interactions. Compounds 2 and 3 are one-dimensional (1-D) coordination polymers containing an eight coordinated Ca(II) situated in a general position and a nine coordinated Sr(II) located on a twofold axis. The μ₂-bridging tridentate binding modes of the crystallographically independent 4-npa ligands in 2 and the unique 4-npa ligand in 3 link the bivalent metal ions into an infinite chain with alternating Ca· · · Ca separations of 3.989 and 4.009 Å, respectively, and a single Sr· · · Sr separation of 4.194Å in the 1-D chain.

  15. Methane absorption and application of mixed organic aggregate prepared from Span80 and alkaline salt

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The water-based materials for mine gas absorption and explosion suppression were prepared, in which the mixed organic aggregate of Span80 and alkaline salt can be used as methane absorbent. Methane was used as a model of mine gas, and the absorptions of methane with different complex materials were studied using head space gas chromatography. Then the state of aqueous material was characterized with laser light scattering instrument and the effects of different complex materials on explosion suppression were preliminarily studied in explosion chamber which can simulate mine gas explosion. The research results showed that complex material could absorb methane and there was some corre- lation between the mean diameter of organic aggregate in aqueous material and the absorption effect. Additionally, the aqueous material could suppress the methane explosion to some degree. The material can absorb mine gas in atomization condition, therefore, degrease mine gas concentration and influence the distribution of mine gas in the space, and then suppress the mine gas explosion to some extent.

  16. Ion Recognition Approach to Volume Reduction of Alkaline Tank Waste by Separation of Sodium Salts

    Energy Technology Data Exchange (ETDEWEB)

    Moyer, Bruce A.; Bonnesen, Peter V.; Custelcean, Radu; Delmau, Laetitia H.; Engle, Nancy L.; Kang, Hyun-Ah; Keever, Tamara J.; Marchand, Alan P.; Gadthula, Srinivas; Gore, Vinayak K.; Huang, Zilin; Sivappa, Rasapalli; Tirunahari, Pavan K.; Levitskaia, Tatiana G.; Lumetta, Gregg J.

    2005-09-26

    The purpose of this research involving collaboration between Oak Ridge National Laboratory (ORNL) and Pacific Northwest National Laboratory (PNNL) is to explore new approaches to the separation of sodium hydroxide, sodium nitrate, and other sodium salts from high-level alkaline tank waste. The principal potential benefit is a major reduction in disposed waste volume, obviating the building of expensive new waste tanks and reducing the costs of vitrification. Principles of ion recognition are being researched toward discovery of liquid-liquid extraction systems that selectively separate sodium hydroxide and sodium nitrate from other waste components. The successful concept of pseudo hydroxide extraction using fluorinated alcohols and phenols is being developed at ORNL and PNNL toward a greater understanding of the controlling equilibria, role of solvation, and of synergistic effects involving crown ethers. Synthesis efforts are being directed toward enhanced sodium binding by crown ethers, both neutral and proton-ionizable. Studies with real tank waste at PNNL will provide feedback toward solvent compositions that have promising properties.

  17. Methane absorption and application of mixed organic aggregate prepared from Span80 and alkaline salt

    Institute of Scientific and Technical Information of China (English)

    ZHANG ZengZhi; GU Na; CAO Lei; SHU XinQian

    2009-01-01

    The water-based materials for mine gas absorption and explosion suppression were prepared,in which the mixed organic aggregate of SpanS0 and alkaline salt can be used as methane absorbent.Methane was used as a model of mine gas,and the absorptions of methane with different complex materials were studied using head space gas chromatography.Then the state of aqueous material was characterized with laser light scattering instrument and the effects of different complex materials on explosion suppression were preliminarily studied in explosion chamber which can simulate mine gas explosion.The research results showed that complex material could absorb methane and there was some correlation between the mean diameter of organic aggregate in aqueous material and the absorption effect.Additionally,the aqueous material could suppress the methane explosion to some degree.The material can absorb mine gas in atomization condition,therefore,degrease mine gas concentration and influence the distribution of mine gas in the space,and then suppress the mine gas explosion to some extent.

  18. Oxidative dissolution of spent nuclear fuel in aqueous alkaline solutions - An alternative to the Purex process?

    Energy Technology Data Exchange (ETDEWEB)

    Runde, Wolfgang; Peper, Shane; Brodnax, Lia; Crooks, William; Zehnder, Ralph; Jarvinen, Gordon

    2004-07-01

    As an alternative to acidic reprocessing of spent nuclear, oxidative dissolution of UO{sub 2} into aqueous alkaline solutions and subsequent separation of fission products is considered. The efficacy of such a method is limited by the kinetics of the UO{sub 2} dissolution and the capacity of alkaline solutions for dissolved U(VI) species. We performed a series of dissolution studies on UO{sub 2} and U{sub 3}O{sub 8} in aqueous alkaline solutions applying various oxidants. Among the oxidative agents commonly used to transform low-valence actinides into their higher oxidation states, H{sub 2}O{sub 2} has proven to be the most effective in basic media. Consequently, we investigated the dissolution of UO{sub 2} and U{sub 3}O{sub 8} in NaOH-H{sub 2}O{sub 2} and Na{sub 2}CO{sub 3}-H{sub 2}O{sub 2} solutions and determined the dissolution kinetics as a function of peroxide and hydroxide (carbonate) concentrations. Methods to remove fission products, e.g., Cs, Sr, Ba and Zr, from alkaline solutions will be evaluated based upon their decontamination factors. We will discuss the feasibility of using chemically oxidizing alkaline solutions as an alternative spent nuclear fuel reprocessing method based on results from experimental quantitative investigations. (authors)

  19. Anodic dissolution of gold in alkaline solutions containing thiourea, thiosulfate and sulfite ions

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Gold dissolves electrochemically in alkaline solutions containing ligands to form complex ions with gold ion. Therefore, selective leaching of noble metals is expected without dissolution of base metals such as steels, aluminum alloys in scrap treatment. Gold electrodes were investigated using linear sweep voltammetry, EQCM method and potentiostatic electrolysis in alkaline solutions containing thiourea, Na2SO3 and Na2S2O3. The solution composition, electrode potential affect gold dissolution rate and current efficiency. The gold dissolved from anode electrode forms complex ions, suspension particles as compound precipitates and deposits on cathode electrode as a metal. Anodic efficiency for gold dissolution is between 10% and 22%. This is caused by the oxidation decomposition of sulfite ions and thiourea. The stability of the alkaline solution containing these elements was also estimated by capillary electrophoresis technique.

  20. SWELLING EQUILIBRIUM OF NONIONIC POLYACRYLAMIDE HYDROGEL IN AQUEOUS SALT SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A series of nonionic polyacrylamide hydrogels, using acrylamide as monomer and N,N’-methylene diacrylamide as crosslinking agent, were prepared by the free radical polymerization in aqueous solution. Swelling equilibria for the gels were carried out in aqueous solutions of NaCl, KCl, CaCl2, Na2HPO4 and K2HPO4 with concentration ranging from 10-3 to 5mol/kgH2O at 25℃. Experimental results revealed that the chlorides and phosphates cause a different behavior at higher salt concentration. The swelling ratio increases with increasing concentration of chlorides salts, while decreases with the increased phosphates salt concentration. The phenomena seem to be related to the different interactions of chloride and hydrogen phosphate ions with the network groups. Furthermore, the effects of different concentration of crosslinking agent and total monomers on gel swelling performance were also investigated.

  1. Scattering of light by charged colloidal particles in salt solutions

    NARCIS (Netherlands)

    Vrij, A.; Overbeek, J.Th.G.

    1962-01-01

    In the interpretation of light scattering by colloidal electrolytes in salt solutions the interaction between the colloidal particles and the low molecular weight ions has to be taken into account. When fluctuation theory is applied for the derivation of a light-scattering equation, nonelectroneutra

  2. Modification of FGD gypsum in hydrothermal mixed salt solution

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-qin; WU Zhong-biao

    2006-01-01

    A novel utilization way of the sludge from wet calcium-based flue gas desulfurization (FGD) processes has been developed in this paper. This study focused on the conversion of the FGD gypsum into α-hemihydrate calcium sulfate by a hydrothermal salt solution method at atmospheric pressure. Experimental study has been carried out in a batch reactor. Qualitative and quantitative analyses were made by DSC/TG thermal analysis, SEM, XRD, metalloscope and chemical analysis. The experimental results showed that the modification of FGD gypsum was controlled by the dissolution and recrystallization mechanisms. With the introduction of FGD gypsum the salt solution was supersaturated, then crystal nucleus of α-hemihydrate calcium sulfate were produced in the solution. With the submicroscopic structure of FGD gypsum crystal changed, the crystal nucleus grew up into α-hemihydrate calcium sulfate crystals. Thus, the modification of FGD gypsum was fulfilled.

  3. Polyaniline Formed in Alkaline Solution -A New Luminous Material

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Electropolymerization of aniline in KOH solution and properties of the polymer are studied by using in situ reflex ellipsometry, cyclic voltammetry and fluorescence spectroscopic method. The change patterns of ellipsometric parameters and the thickness of film in the process of electropolymerization are investigated. The complex refractive indices and the fluorescence spectra of PAN indicate that the PAN is a new kind of luminous material.

  4. Passivation behavior of a ferritic stainless steel in concentrated alkaline solutions

    Directory of Open Access Journals (Sweden)

    Arash Fattah-alhosseini

    2015-10-01

    Full Text Available The passivation behavior of AISI 430 ferritic stainless steel was investigated in concentrated alkaline solutions in relation to several test parameters, using electrochemical techniques. Increasing solution pH (varying from 11.5 to 14.0 leads to an increase in the corrosion rate of the alloy. Mott–Schottky analysis revealed that passive films formed on AISI 430 ferritic stainless steel behave as n-type semiconductor and the donor densities increased with pH. Electrochemical impedance spectroscopy (EIS results showed that the reciprocal capacitance of the passive film is directly proportional to its thickness, which decreases with pH increase. The results revealed that for this ferritic stainless steel in concentrated alkaline solutions, decreasing the solution pH offers better conditions for forming passive films with higher protection behavior, due to the growth of a much thicker and less defective film.

  5. Hydrogen sorption in Pd monolayers in alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Martin, M.H. [Departement de chimie, Universite de Sherbrooke, 2500 blvd. de l' Universite, Sherbrooke, Quebec, J1K 2R1 (Canada); Lasia, A. [Departement de chimie, Universite de Sherbrooke, 2500 blvd. de l' Universite, Sherbrooke, Quebec, J1K 2R1 (Canada)], E-mail: a.lasia@usherbrooke.ca

    2009-09-01

    Hydrogen adsorption/absorption at palladium monolayers (ML) deposited on monocrystalline Au(1 1 1) electrode was studied in 0.1 M NaOH solution. H charge isotherms demonstrated that adsorption started at potentials more positive than at thicker nanometric Pd/Au(polycrystal) deposits. Due to 3-dimensional deposit growth, absorption could be seen at all deposits thicker than 1 ML. Besides, H sorption at Pd/Au(1 1 1) monolayers was more reversible than at nanometric Pd/Au(polycrystal) deposits. Strong geometric and electronic effects due to the Au substrate were observed up to 5 Pd ML. Influence of benzotriazole (BTA) on H sorption was also investigated. BTA blocked H adsorption above 250 mV vs. RHE. At less positive potentials adsorbed BTA layer seemed to undergo a reorientation allowing H adsorption. Stationary and dynamic electrochemical impedance spectroscopy was used to obtain double layer capacitance and charge transfer resistance. BTA also promoted kinetically H sorption into Pd/Au(1 1 1) monolayer and Pd/Au(polycrystal) nanometric deposits.

  6. Electrical conductivity of aqueous solutions of aluminum salts

    Science.gov (United States)

    Vila, J.; Rilo, E.; Segade, L.; Cabeza, O.; Varela, L. M.

    2005-03-01

    We present experimental measurements of the specific electrical conductivity (σ) in aqueous solutions of aluminum salts at different temperatures, covering all salt concentrations from saturation to infinite dilution. The salts employed were AlCl3 , AlBr3 , AlI3 , and Al(NO3)3 , which present a 1:3 relationship between the electrical charges of anion and cation. In addition, we have measured the density in all ranges of concentrations of the four aqueous electrolyte solutions at 298.15K . The measured densities show an almost linear behavior with concentration, and we have fitted it to a second order polynomial with very high degree of approximation. The measurement of the specific conductivity at constant temperature reveals the existence of maxima in the conductivity vs concentration curves at molar concentrations around 1.5M for the three halide solutions studied, and at approximately 2M for the nitrate. We present a theoretical foundation for the existence of these maxima, based on the classical Debye-Hückel-Onsager hydrodynamic mean-field framework for electrical transport and its high concentration extensions, and also a brief consideration of ionic frictional coefficients using mode-coupling theory. We also found that the calculated values of the equivalent conductance vary in an approximately linear way with the square root of the concentration at concentrations as high as those where the maximum of σ appears. Finally, and for completeness, we have measured the temperature dependence of the electrical conductivity at selected concentrations from 283to353K , and performed a fit to an exponential equation of the Vogel-Fulcher-Tamman type. The values of the calculated temperatures of null mobility of the four salts are reported.

  7. Methanol synthesis using a catalyst combination of alkali or alkaline earth salts and reduced copper chromite for methanol synthesis

    Science.gov (United States)

    Tierney, John W.; Wender, Irving; Palekar, Vishwesh M.

    1993-01-01

    The present invention relates to a novel route for the synthesis of methanol, and more specifically to the production of methanol by contacting synthesis gas under relatively mild conditions in a slurry phase with a catalyst combination comprising reduced copper chromite and basic alkali salts or alkaline earth salts. The present invention allows the synthesis of methanol to occur in the temperature range of approximately 100.degree.-160.degree. C. and the pressure range of 40-65 atm. The process produces methanol with up to 90% syngas conversion per pass and up to 95% methanol selectivity. The only major by-product is a small amount of easily separated methyl formate. Very small amounts of water, carbon dioxide and dimethyl ether are also produced. The present catalyst combination also is capable of tolerating fluctuations in the H.sub.2 /CO ratio without major deleterious effect on the reaction rate. Furthermore, carbon dioxide and water are also tolerated without substantial catalyst deactivation.

  8. A study on the mechanism of stress corrosion cracking of duplex stainless steels in hot alkaline-sulfide solution

    Science.gov (United States)

    Chasse, Kevin Robert

    Duplex stainless steels (DSS) generally have superior strength and corrosion resistance as compared to most standard austenitic and ferritic stainless grades owing to a balanced microstructure of austenite and ferrite. As a result of having favorable properties, DSS have been selected for the construction of equipment in pulp and paper, chemical processing, nuclear, oil and gas as well as other industries. The use of DSS has been restricted in some cases because of stress corrosion cracking (SCC), which can initiate and grow in either the ferrite or austenite phase depending on the environment. Thorough understanding of SCC mechanisms of DSS in chloride- and hydrogen sulfide-containing solutions has been useful for material selection in many environments. However, understanding of SCC mechanisms of DSS in sulfide-containing caustic solutions is limited, which has restricted the capacity to optimize process and equipment design in pulp and paper environments. Process environments may contain different concentrations of hydroxide, sulfide, and chloride, altering corrosion and SCC susceptibility of each phase. Crack initiation and growth behavior will also change depending on the relative phase distribution and properties of austenite and ferrite. The role of microstructure and environment on the SCC of standard grade UNS S32205 and lean grade UNS S32101 in hot alkaline-sulfide solution were evaluated in this work using electrochemical, film characterization, mechanical testing, X-ray diffraction, and microscopy techniques. Microstructural aspects, which included residual stress state, phase distribution, phase ratio, and microhardness, were related to the propensity for SCC crack initiation in different simulated alkaline pulping liquors at 170 °C. Other grades of DSS and reference austenitic and superferritic grades of stainless steel were studied using exposure coupons for comparison to understand compositional effects and individual phase susceptibility

  9. Cast iron deterioration with time in various aqueous salt solutions

    Indian Academy of Sciences (India)

    Rita Mehra; Aditi Soni

    2002-02-01

    The changes with time in the corrosion rate and corrosion current density on a cast iron electrode in various aqueous salt solutions have been carried out using total immersion test and potentiostatic polarization curves. The concentration of salts taken is expected to be present in potable water. The relative behaviour of these salts towards corrosion has also been studied, which is found to be different from previous studies. The total immersion test parameters viz. weight loss, corrosion rate as well as potentiostatic parameters, open circuit potential, corr, Tafel slopes, corrosion rate, have been calculated by standard methods. Besides these the relative increase in corrosion rate with time as well as the percentage to which corrosion rate should be decreased so as to provide protection towards corrosion have also been calculated. It was found that KCl and NaCl are major contributors than MnSO4, Pb(NO3)2, KI and KBr. The relative increase in corrosion is high in KBr, KI, NaNO3, CaCl2, and less in Pb(NO3)2, NaHCO3 and CaCO3 test solutions. For the reliability of results the data has been statistically analysed.

  10. Bioprecipitation of uranium from alkaline waste solutions using recombinant Deinococcus radiodurans

    Energy Technology Data Exchange (ETDEWEB)

    Kulkarni, Sayali; Ballal, Anand; Apte, Shree Kumar, E-mail: aptesk@barc.gov.in

    2013-11-15

    Highlights: • Deinococcus radiodurans was genetically engineered to overexpress alkaline phosphatase (PhoK). • Deino-PhoK bioprecipitated U efficiently over a wide range of input U concentration. • A maximal loading of 10.7 g U/g of biomass at 10 mM input U was observed. • Radioresistance and U precipitation by Deino-PhoK remained unaffected by γ radiation. • Immobilization of Deino-PhoK facilitated easy separation of precipitated U. -- Abstract: Bioremediation of uranium (U) from alkaline waste solutions remains inadequately explored. We engineered the phoK gene (encoding a novel alkaline phosphatase, PhoK) from Sphingomonas sp. for overexpression in the radioresistant bacterium Deinococcus radiodurans. The recombinant strain thus obtained (Deino-PhoK) exhibited remarkably high alkaline phosphatase activity as evidenced by zymographic and enzyme activity assays. Deino-PhoK cells could efficiently precipitate uranium over a wide range of input U concentrations. At low uranyl concentrations (1 mM), the strain precipitated >90% of uranium within 2 h while a high loading capacity of around 10.7 g U/g of dry weight of cells was achieved at 10 mM U concentration. Uranium bioprecipitation by Deino-PhoK cells was not affected in the presence of Cs and Sr, commonly present in intermediate and low level liquid radioactive waste, or after exposure to very high doses of ionizing radiation. Transmission electron micrographs revealed the extracellular nature of bioprecipitated U, while X-ray diffraction and fluorescence analysis identified the precipitated uranyl phosphate species as chernikovite. When immobilized into calcium alginate beads, Deino-PhoK cells efficiently removed uranium, which remained trapped in beads, thus accomplishing physical separation of precipitated uranyl phosphate from solutions. The data demonstrate superior ability of Deino-PhoK, over earlier reported strains, in removal of uranium from alkaline solutions and its potential use in

  11. Inhibition of Brass Corrosion by 2-Mercapto-1-methylimidazole in Weakly Alkaline Solution

    Science.gov (United States)

    Radovanovic, Milan B.; Antonijevic, Milan M.

    2016-03-01

    The electrochemical behavior of brass and anticorrosion effect of 2-mercapto-1-methylimidazole (2-MMI) in weakly alkaline solution with and without presence of chloride ions was investigated using electrochemical techniques in addition to SEM-EDS analysis. Results show that inhibition efficiency depended on inhibitor concentration and immersion time of brass electrode in inhibitor solution. Inhibition mechanism of 2-mercapto-1-methylimidazole includes adsorption of inhibitor on active sites on electrode surface which was confirmed by SEM-EDS analysis of the brass. Adsorption of the 2-MMI in sodium tetraborate solution obeys Flory-Huggins adsorption isotherm, while in the presence of chloride, ions adsorption of inhibitor obeys Langmuir adsorption isotherm.

  12. Recombination of Geminate (OH,eaq-) Pairs in Concentrated Alkaline Solutions: Lack of Evidence For Hydroxyl Radical Deprotonation

    CERN Document Server

    Lian, R; Shkrob, I A; Bartels, D M; Oulianov, D A; Gosztola, D J; Lian, Rui; Crowell, Robert A.; Shkrob, Ilya A.; Bartels, David M.; Oulianov, Dmitri A.; Gosztola, David

    2004-01-01

    Picosecond dynamics of hydrated electrons and hydroxyl radicals generated in 200 nm photodissociation of aqueous hydroxide and 400 nm (3-photon) ionization of water in concentrated alkaline solutions were obtained. No deprotonation of hydroxyl radicals was observed on sub-nanosecond time scale, even in 1-10 M KOH solutions. This result is completely at odds with the kinetic data for deprotonation of OH radical in dilute alkaline solutions. We suggest that the deprotonation of hydroxyl radical is slowed down dramatically in concentrated alkaline solutions.

  13. Effect of different alkaline solutions on crystalline structure of cellulose at different temperatures.

    Science.gov (United States)

    Keshk, Sherif M A S

    2015-01-22

    Effect of alkaline solutions such as 10% NaOH, NaOH/urea and NaOH/ethylene glycol solutions on crystalline structure of different cellulosic fibers (cotton linter and filter paper) was investigated at room temperature and -4°C. The highest dissolution of cotton linter and filter paper was observed in NaOH/ethylene glycol at both temperatures. X-ray patterns of treated cotton linter with different alkaline solutions at low temperature showed only two diffractions at 2θ=12.5° and 21.0°, which belonged to the crystalline structure of cellulose II. CP/MAS (13)C NMR spectra showed the doublet peaks at 89.2 ppm and 88.3 ppm representing C4 resonance for cellulose I at room temperature, Whereas, at low temperature the doublet peaks were observed at 89.2 ppm and 87.8 ppm representing C4 resonance for cellulose II. Degree of polymerization of cellulose plays an important role in cellulose dissolution in different alkaline solutions and temperatures, where, a low temperature gives high dissolutions percentage with change in crystalline structure from cellulose I to cellulose II forms.

  14. Alkaline unfolding and salt-induced folding of yeast alcohol dehydrogenase under high pH conditions.

    Science.gov (United States)

    Le, W P; Yan, S X; Li, S; Zhong, H N; Zhou, H M

    1996-06-01

    The conformational changes of yeast alcohol dehydrogenase during unfolding at alkaline pH have been followed by fluorescence emission and circular dichroism spectra. A result of comparison of inactivation and conformational changes shows that much lower values of alkaline pH are required to bring about inactivation than significant conformational change of the enzyme molecule. At pH 9.5, although the enzyme has been completely inactivated, no marked conformational changes can be observed. Even at pH 12, the apparently fully unfolded enzyme retains some ordered secondary structure. After removal of Zn2+ from the enzyme molecule, the conformational stability decreased. At pH 12 by adding the salt, the relatively unfolded state of denatured enzyme changes into a compact conformational state by hydrophobic collapsing. Folded states induced by salt bound ANS strongly, indicating the existence of increased hydrophobic surface. More extensive studies showed that although apo-YADH and holo-YADH exhibited similar behavior, the folding cooperative ability of apo-enzyme was lower than that of holo-enzyme. The above results suggest that the zinc ion plays an important role in helping the folding of YADH and in stabilizing its native conformation.

  15. Blending Of Radioactive Salt Solutions In Million Gallon Tanks

    Energy Technology Data Exchange (ETDEWEB)

    Leishear, Robert A.; Lee, Si Y.; Fowley, Mark D.; Poirier, Michael R.

    2012-12-10

    Research was completed at Savannah River National Laboratory (SRNL) to investigate processes related to the blending of radioactive, liquid waste, salt solutions in 4920 cubic meter, 25.9 meter diameter storage tanks. One process was the blending of large salt solution batches (up to 1135 ? 3028 cubic meters), using submerged centrifugal pumps. A second process was the disturbance of a settled layer of solids, or sludge, on the tank bottom. And a third investigated process was the settling rate of sludge solids if suspended into slurries by the blending pump. To investigate these processes, experiments, CFD models (computational fluid dynamics), and theory were applied. Experiments were performed using simulated, non-radioactive, salt solutions referred to as supernates, and a layer of settled solids referred to as sludge. Blending experiments were performed in a 2.44 meter diameter pilot scale tank, and flow rate measurements and settling tests were performed at both pilot scale and full scale. A summary of the research is presented here to demonstrate the adage that, ?One good experiment fixes a lot of good theory?. Experimental testing was required to benchmark CFD models, or the models would have been incorrectly used. In fact, CFD safety factors were established by this research to predict full-scale blending performance. CFD models were used to determine pump design requirements, predict blending times, and cut costs several million dollars by reducing the number of required blending pumps. This research contributed to DOE missions to permanently close the remaining 47 of 51 SRS waste storage tanks.

  16. MODELING AN ION EXCHANGE PROCESS FOR CESIUM REMOVAL FROM ALKALINE RADIOACTIVE WASTE SOLUTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Smith, F; Luther Hamm, L; Sebastian Aleman, S; Johnston Michael, J

    2008-08-26

    The performance of spherical Resorcinol-Formaldehyde ion-exchange resin for the removal of cesium from alkaline radioactive waste solutions has been investigated through computer modeling. Cesium adsorption isotherms were obtained by fitting experimental data using a thermodynamic framework. Results show that ion-exchange is an efficient method for cesium removal from highly alkaline radioactive waste solutions. On average, two 1300 liter columns operating in series are able to treat 690,000 liters of waste with an initial cesium concentration of 0.09 mM in 11 days achieving a decontamination factor of over 50,000. The study also tested the sensitivity of ion-exchange column performance to variations in flow rate, temperature and column dimensions. Modeling results can be used to optimize design of the ion exchange system.

  17. Electrochemical Reduction of Oxygen on Multi-walled Carbon Nanotubes Electrode in Alkaline Solution

    Institute of Scientific and Technical Information of China (English)

    You Qun CHU; Chun An MA; Feng Ming ZHAO; Hui HUANG

    2004-01-01

    The multi-walled carbon nanotubes (MWNTs) electrode was constructed using poly- tetrafluoroethylene as binder, and the electrochemical reductive behavior of oxygen in alkaline solution was first examined on this electrode. Compared with other carbon materials, MWNTs show higher electrocatalytic activity, and the reversibility of O2 reduction reaction is greatly improved. The experiments reveal that the electrochemical reduction of O2 to HO2- is controlled by adsorption. The preliminary results illustrate the potential application of MWNTs in fuel cells.

  18. CO2 Capture from Flue Gas using Amino Acid Salt Solutions

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai; Stenby, Erling Halfdan; Thomsen, Kaj

    2009-01-01

    difficult. Amino acid salt solutions have emerged as an alternative to the alkanolamine solutions. A number of advantages make amino acid salt solutions attractive solvents for CO2 capture from flue gas. In the present study CO2 absorption in aqueous solutions of 0.5 M potassium glycinate and 0.5 M...

  19. Optical Sensor for Characterizing the Phase Transition in Salted Solutions

    Science.gov (United States)

    Claverie, Rémy; Fontana, Marc D.; Duričković, Ivana; Bourson, Patrice; Marchetti, Mario; Chassot, Jean-Marie

    2010-01-01

    We propose a new optical sensor to characterize the solid-liquid phase transition in salted solutions. The probe mainly consists of a Raman spectrometer that extracts the vibrational properties from the light scattered by the salty medium. The spectrum of the O – H stretching band was shown to be strongly affected by the introduction of NaCl and the temperature change as well. A parameter SD defined as the ratio of the integrated intensities of two parts of this band allows to study the temperature and concentration dependences of the phase transition. Then, an easy and efficient signal processing and the exploitation of a modified Boltzmann equation give information on the phase transition. Validations were done on solutions with varying concentration of NaCl. PMID:22319327

  20. Direct Hydrothermal Precipitation of Pyrochlore-Type Tungsten Trioxide Hemihydrate from Alkaline Sodium Tungstate Solution

    Science.gov (United States)

    Li, Xiaobin; Li, Jianpu; Zhou, Qiusheng; Peng, Zhihong; Liu, Guihua; Qi, Tiangui

    2012-04-01

    Pyrochlore-type tungsten trioxide hemihydrate (WO3·0.5H2O) powder with the average particle size of 0.5 μm was prepared successfully from the weak alkaline sodium tungstate solution by using organic substances of sucrose or cisbutenedioic acid as the acidification agent. The influences of solution pH and acidification agents on the precipitation process were investigated. The results showed that organic acidification agents such as sucrose and cisbutenedioic acid could improve the precipitation of pyrochlore WO3·0.5H2O greatly from sodium tungstate solution compared with the traditional acidification agent of hydrochloric acid. In addition, the pH value of the hydrothermal system played a critical role in the precipitation process of WO3·0.5H2O, and WO3·0.5H2O precipitation mainly occured in the pH range of 7.0 to 8.5. The precipitation rate of tungsten species in the sodium tungstate solution could reach up to 98 pct under the optimized hydrothermal conditions. This article proposed also the hydrothermal precipitation mechanism of WO3·0.5H2O from the weak alkaline sodium tungstate solution. The novel method reported in this study has a great potential to improve the efficiency of advanced tungsten trioxide-based functional material preparation, as well as for the pollution-reducing and energy-saving tungsten extractive metallurgy.

  1. Pt-decorated nanoporous gold for glucose electrooxidation in neutral and alkaline solutions

    Directory of Open Access Journals (Sweden)

    Yan Xiuling

    2011-01-01

    Full Text Available Abstract Exploiting electrocatalysts with high activity for glucose oxidation is of central importance for practical applications such as glucose fuel cell. Pt-decorated nanoporous gold (NPG-Pt, created by depositing a thin layer of Pt on NPG surface, was proposed as an active electrode for glucose electrooxidation in neutral and alkaline solutions. The structure and surface properties of NPG-Pt were characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray powder diffraction (XRD, and cyclic voltammetry (CV. The electrocatalytic activity toward glucose oxidation in neutral and alkaline solutions was evaluated, which was found to depend strongly on the surface structure of NPG-Pt. A direct glucose fuel cell (DGFC was performed based on the novel membrane electrode materials. With a low precious metal load of less than 0.3 mg cm-2 Au and 60 μg cm-2 Pt in anode and commercial Pt/C in cathode, the performance of DGFC in alkaline is much better than that in neutral condition.

  2. Comparative study of polypyrrole films electrosynthesized in alkaline and acid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Lehr, I.L. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina); Quinzani, O.V. [Departamento de Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina); Saidman, S.B., E-mail: ssaidman@criba.edu.ar [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina)

    2009-09-15

    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.

  3. Detection of salt bridges to lysines in solution in barnase

    DEFF Research Database (Denmark)

    Hansen, Poul Erik; Williamson, Michael P.; Hounslow, Andrea M.

    2013-01-01

    We show that salt bridges involving lysines can be detected by deuterium isotope effects on NMR chemical shifts of the sidechain amine. Lys27 in the ribonuclease barnase is salt bridged, and mutation of Arg69 to Lys retains a partially buried salt bridge. The salt bridges are functionally important....

  4. Study of the electrochemical oxidation mechanism of formaldehyde on gold electrode in alkaline solution

    Institute of Scientific and Technical Information of China (English)

    Rui-Wen Yan; Bao-Kang Jin

    2013-01-01

    The oxidation of formaldehyde in alkaline solution was studied by in situ rapid-scan time-resolved IR spectroelectrochemistry (RS-TR-FTIRS) method.In the potential range between-0.7 V and 0.2 V,the gem-diol anions were oxidized (according to the 2765 cm-1 ofvH-o and 1034 cm-1 ofvco downward IR bands) and the formate ions appeared (according to the 1588,1357 cm-1 of the asymmetric and symmetricvoco and 1380 cm-1 ofδc-H upward IR bands) in aqueous solution.It was also confirmed that gem-diol anion was oxidized (according to the 2026,1034 cm-1 downward IR bands) to formate ions (according to the 1595,1357,1380 cm-1 upward IR bands) and water (according to the 3427 cm-1 ofvH-o upward IR band) in heavy water solution.The results illustrated that formaldehyde formed gem-diol anion in alkaline solution and was absorbed on the electrode surface; then gem-diol anion was oxidized to formate ions and water.

  5. Comparison of Inactivation and Unfolding of Calf Intestinal Alkaline Phosphatase in Guanidinium Chloride Solution

    Institute of Scientific and Technical Information of China (English)

    张英侠; 闫淑莲; 刘永利; 席宏伟; 周海梦

    2002-01-01

    The changes in activity and unfolding of calf intestinal alkaline phosphatase (CIP) during denaturation in guanidinium chloride solutions of different concentrations were investigated using ultraviolet difference absorption spectra and fluorescence emission spectra. Unfolding and inactivation rate constants were measured and compared. The inactivation course is much faster than that of unfolding, which suggests that the active site of CIP containing two zinc ions and one magnesium ion is situated in a limited and flexible region of the enzyme molecule, which is more fragile to the denaturant than the protein as a whole.

  6. Preparation, characterization and application of alkaline leached CuNiZn ternary coatings for long-term electrolysis in alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Solmaz, Ramazan [Bingoel University, Science and Letters Faculty, Chemistry Department, 12000 Bingoel (Turkey); Doener, Ali; Kardas, Guelfeza [Cukurova University, Science and Letters Faculty, Chemistry Department, 01330 Balcali Adana (Turkey)

    2010-10-15

    The NiCuZn ternary coating was electrochemically deposited on a copper electrode. Then, it was etched in a concentrated alkaline solution (30% NaOH) to produce a porous and electrocatalytic surface suitable for use in the hydrogen evolution reaction (HER). The surface composition of coating before and after alkaline leaching was determined by energy dispersive X-ray (EDX) analysis. The surface morphologies were investigated by scanning electron microscopy (SEM). The long-term stability of electrode prepared for alkaline water electrolysis was investigated in 1 M KOH solution with the help of cathodic current-potential curves and electrochemical impedance spectroscopy (EIS) techniques. It was found that, the NiCuZn coating has a compact and porous structure with good physical stability. Alkaline leaching process further improved the activity of NiCuZn coating in comparison with binary NiCu deposit for the HER. The long-term operation at -100 mA cm{sup -2} showed good electrochemical stability over 120 h. (author)

  7. The effect of divalent salt in chondroitin sulfate solutions

    Science.gov (United States)

    Aranghel, D.; Badita, C. R.; Radulescu, A.; Moldovan, L.; Craciunescu, O.; Balasoiu, M.

    2016-03-01

    Chondroitin-4 sulfate (CS4) is the main glycosaminoglycan extracted from bovine trachea. CS4 play an important role in osteoarthritis treatment, anticoagulant activity, reduces the degradation of cartilage matrix components, reduces necrosis and apoptosis of chondrocytes and reduces the activity of collagenase. Chondroitin sulfate is also responsible for proteoglycans degradation. Chondroitin sulfate can bind calcium ions with different affinities, depending on their sulfation position. The purpose of this study was to determine the structural properties and the influence of Ca2+ cations. We carried out measurements on CS4 solutions and mixtures of liquid CS4 with Ca2+ by Small-Angle Neutron Scattering (SANS). CS4 have a mass fractal behavior and the addition of a salt (CaCl2) in CS4 solutions generates the appearance of a correlation peak due to local ordering between adjacent chains with inter-chain distances between 483 Å and 233 Å for a calcium concentration of 0.01% w/w.

  8. Effect of Additional Sulfide and Thiosulfate on Corrosion of Q235 Carbon Steel in Alkaline Solutions

    Directory of Open Access Journals (Sweden)

    Bian Li Quan

    2016-01-01

    Full Text Available This paper investigated the effect of additional sulfide and thiosulfate on Q235 carbon steel corrosion in alkaline solutions. Weight loss method, scanning electron microscopy (SEM equipped with EDS, X-ray photoelectron spectroscopy (XPS, and electrochemical measurements were used in this study to show the corrosion behavior and electrochemistry of Q235 carbon steel. Results indicate that the synergistic corrosion rate of Q235 carbon steel in alkaline solution containing sulfide and thiosulfate is larger than that of sulfide and thiosulfate alone, which could be due to redox reaction of sulfide and thiosulfate. The surface cracks and pitting characteristics of the specimens after corrosion were carefully examined and the corrosion products film is flake grains and defective. The main corrosion products of specimen induced by S2− and S2O32- are FeS, FeS2, Fe3O4, and FeOOH. The present study shows that the corrosion mechanism of S2− and S2O32- is different for the corrosion of Q235 carbon steel.

  9. Alkaline deoxygenated graphene oxide as adsorbent for cadmium ions removal from aqueous solutions.

    Science.gov (United States)

    Liu, Jun; Du, Hongyan; Yuan, Shaowei; He, Wanxia; Yan, Pengju; Liu, Zhanhong

    2015-01-01

    Alkaline deoxygenated graphene oxide (aGO) was prepared through alkaline hydrothermal treatment and used as adsorbent to remove Cd(II) ions from aqueous solutions for the first time. The characterization results of transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and Fourier transform infrared (FT-IR) spectra indicate that aGO was successfully synthesized. The batch adsorption experiments showed that the adsorption kinetics could be described by the pseudo-second-order kinetic model, and the isotherms equilibrium data were well fitted with the Langmuir model. The maximum adsorption capacity of Cd(II) on aGO was 156 mg/g at pH 5 and T=293 K. The adsorption thermodynamic parameters indicated that the adsorption process was a spontaneous and endothermic reaction. The mainly adsorption mechanism speculated from FT-IR results may be attributed to the electrostatic attraction between Cd2+ and negatively charged groups (-CO-) of aGO and cation-π interaction between Cd2+ and the graphene planes. The findings of this study demonstrate the potential utility of the nanomaterial aGO as an effective adsorbent for Cd(II) removal from aqueous solutions.

  10. On the complex structural diffusion of proton holes in nanoconfined alkaline solutions within slit pores

    Science.gov (United States)

    Muñoz-Santiburcio, Daniel; Marx, Dominik

    2016-08-01

    The hydroxide anion OH-(aq) in homogeneous bulk water, that is, the solvated proton hole, is known to feature peculiar properties compared with excess protons solvated therein. In this work, it is disclosed that nanoconfinement of such alkaline aqueous solutions strongly affects the key structural and dynamical properties of OH-(aq) compared with the bulk limit. The combined effect of the preferred hypercoordinated solvation pattern of OH-(aq), its preferred perpendicular orientation relative to the confining surfaces, the pronounced layering of nanoconfined water and the topology of the hydrogen bond network required for proton hole transfer lead to major changes of the charge transport mechanism, in such a way that the proton hole migration mechanism depends exquisitely on the width of the confined space that hosts the water film. Moreover, the anionic Zundel complex, which is of transient nature in homogeneous bulk solutions, can be dynamically trapped as a shallow intermediate species by suitable nanoconfinement conditions.

  11. Investigation of electrochemical synthesis of ferrate, Part I: Electrochemical behavior of iron and its several alloys in concentrated alkaline solutions

    Directory of Open Access Journals (Sweden)

    Čekerevac Milan I.

    2009-01-01

    Full Text Available In recent years, considerable attention has been paid to various applications of Fe(VI due to its unique properties such as oxidizing power, selective reactivity, stability of the salt, and non-toxic decomposition by-products of ferric ion. In environmental remediation processes, Fe(VI has been proposed as green oxidant, coagulant, disinfectant, and antifoulant. Therefore, it is considered as a promising multi-purpose water treatment chemical. Fe(VI has also potential applications in electrochemical energy source, as 'green cathode'. The effectiveness of ferrate as a powerful oxidant in the entire pH range, and its use in environmental applications for the removal of wide range of contaminants has been well documented by several researchers. There is scientific evidence that ferrate can effectively remove arsenic, algae, viruses, pharmaceutical waste, and other toxic heavy metals. Although Fe(VI was first discovered in early eighteen century, detailed studies on physical and chemical properties of Fe(VI had to wait until efficient synthetic and analytical methods of Fe(VI were developed by Schreyer et al. in the 1950s. Actually, there have been developed three ways for the preparation of Fe(VI compounds : the wet oxidation of Fe(II and Fe(III compounds, the dry oxidation of the same, and the electrochemistry method, mainly based on the trans passive oxidation of iron. High purity ferrates Fe(VI can be generated when electrode of the pure iron metal or its alloys are anodized in concentrated alkaline solution. It is known that the efficiency of electrochemical process of Fe(VI production depends on many factors such as current density, composition of anode material, types of electrolyte etc. In this paper, the electrochemical synthesis of ferrate(VI solution by the anodic dissolution of iron and its alloys in concentrated water solution of NaOH and KOH is investigated. The process of transpassive dissolution of iron to ferrate(VI was studied by

  12. Corrosion-wear behavior of nanocrystalline Fe88Si12 alloy in acid and alkaline solutions

    Science.gov (United States)

    Fu, Li-cai; Qin, Wen; Yang, Jun; Liu, Wei-min; Zhou, Ling-ping

    2017-01-01

    The corrosion-wear behavior of a nanocrystalline Fe88Si12 alloy disc coupled with a Si3N4 ball was investigated in acid (pH 3) and alkaline (pH 9) aqueous solutions. The dry wear was also measured for reference. The average friction coefficient of Fe88Si12 alloy in the pH 9 solution was approximately 0.2, which was lower than those observed for Fe88Si12 alloy in the pH 3 solution and in the case of dry wear. The fluctuation of the friction coefficient of samples subjected to the pH 9 solution also showed similar characteristics. The wear rate in the pH 9 solution slightly increased with increasing applied load. The wear rate was approximately one order of magnitude less than that in the pH 3 solution and was far lower than that in the case of dry wear, especially at high applied load. The wear traces of Fe88Si12 alloy under different wear conditions were examined and analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The results indicated that the tribo-chemical reactions that involve oxidation of the worn surface and hydrolysis of the Si3N4 ball in the acid solution were restricted in the pH 9 aqueous solution. Thus, water lubrication can effectively improve the wear resistance of nanocrystalline Fe88Si12 alloy in the pH 9 aqueous solution.

  13. Alkaline leaching of metal melting industry wastes dseparation of zinc and lead in the leach solution

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this work, a thorough examinations on the extractability of zinc and lead present in the steelmaking dusts using alkaline leaching process and the effectiveness of the zinc and lead separation in the resultant leaching solutions using sulfide precipitation method were made. It was found that only about 53% of zinc and over 70% of the lead could be leached out of the dusts, while the other 47% of zinc and 306 of lead were left in the leaching residues. The zinc and lead in the resultant leaching solution can be effectively and selectively separated. When the weight ratio of sodium sulfide (M. W. = 222-240) to Pb was kept at 1.8, the lead in the solution could be precipitated out quantitatively while all the zinc was remained in the solution. The zinc left in the solution can be further recovered by the addition of extra sodium sulfide with a weight ratio of sodium sulfide to the zinc over 2.6. The resultant filtrate can be recycled to the leaching of dust in the next leaching process.

  14. The mathematics of the total alkalinity-pH equation: pathway to robust and universal solution algorithms

    Science.gov (United States)

    Munhoven, G.

    2013-03-01

    The total alkalinity-pH equation, which relates total alkalinity and pH for a given set of total concentrations of the acid-base systems that contribute to total alkalinity in a given water sample, is reviewed and its mathematical properties established. We prove that the equation function is strictly monotone and always has exactly one positive root. Different commonly used approximations are discussed and compared. An original method to derive appropriate initial values for the iterative solution of the cubic polynomial equation based upon carbonate-borate-alkalinity is presented. We then review different methods that have been used to solve the total alkalinity-pH equation, with a main focus on biogeochemical models. The shortcomings and limitations of these methods are made out and discussed. We then present two variants of a new, robust and universally convergent algorithm to solve the total alkalinity-pH equation. This algorithm does not require any a priori knowledge of the solution. The iterative procedure is shown to converge from any starting value to the physical solution. The extra computational cost for the convergence security is only 10-15% compared to the fastest algorithm in our test series.

  15. Effect of salt solutions on chain structure of partially hydrolyzed polyacrylamide

    Institute of Scientific and Technical Information of China (English)

    张青; 周吉生; 翟永爱; 刘凤岐; 高歌

    2008-01-01

    The effect of salt solutions(NaCl,Na2SO4 and CaCl2) on the conformational properties of partially hydrolyzed polyacrylamide(HPAM) was investigated by using static laser light scattering(SLLS).The special interaction between CaCl2 solution and HPAM was also researched.Experimental results show that the chain structure of HPAM is interrelated with the charge density,the kind and the concentration of salt solutions.The mean-square radius of gyration(Rz) and the second virial coefficient(A2) of HPAM decrease with increasing concentration of salt solutions,and the salt effect tends towards the maximum when the concentration of salt solution is increased to some amount.

  16. Influence of Salts on Electrospinning of Aqueous and Nonaqueous Polymer Solutions

    Directory of Open Access Journals (Sweden)

    Fatma Yalcinkaya

    2015-01-01

    Full Text Available A roller electrospinning system was used to produce nanofibres by using different solution systems. Although the process of electrospinning has been known for over half a century, knowledge about spinning behaviour is still lacking. In this work, we investigated the effects of salt for two solution systems on spinning performance, fibre diameter, and web structure. Polyurethane (PU and polyethylene oxide (PEO were used as polymer, and tetraethylammonium bromide and lithium chloride were used as salt. Both polymer and salt concentrations had a noteworthy influence on the spinning performance, morphology, and diameter of the nanofibres. Results indicated that adding salt increased the spinnability of PU. Salt created complex bonding with dimethylformamide solvent and PU polymer. Salt added to PEO solution decreased the spinning performance of fibres while creating thin nanofibres, as explained by the leaky dielectric model.

  17. ISOPAR L Release Rates from Saltstone Using Simulated Salt Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Bronikowski, M

    2006-02-06

    The Modular Caustic-Side Solvent Extraction (CSSX) Unit (MCU) and the Salt Waste Processing Facility (SWPF) will produce a Deactivated Salt Solution (DSS) that will go to the Saltstone Production Facility (SPF). Recent information indicates that solvent entrainment in the DSS is larger than expected. The main concern is with Isopar{reg_sign} L, the diluent in the solvent mixture, and its flammability in the saltstone vault. If it is assumed that all the Isopar{reg_sign} L is released instantaneously into the vault from the curing grout before each subsequent pour; the Isopar{reg_sign} L in the vault headspace is well mixed; and each pour displaces an equivalent volume of headspace, the allowable concentration of Isopar{reg_sign} L in the DSS sent to SPF has been calculated at approximately 4 ppm. The amount allowed would be higher, if the release from grout were significantly less. The Savannah River National Laboratory was tasked with determining the release of Isopar{reg_sign} L from saltstone prepared with a simulated DSS with Isopar{reg_sign} L concentrations ranging from 50 mg/L to 200 mg/L in the salt fraction and with test temperatures ranging from ambient to 95 C. The results from the curing of the saltstone showed that the Isopar{reg_sign} L release data can be treated as a percentage of initial concentration in the concentration range studied. The majority of the Isopar{reg_sign} L that was released over the test duration was released in the first few days. The release of Isopar{reg_sign} L begins immediately and the rate of release decreases over time. At higher temperatures the immediate release is larger than at lower temperatures. In one test at 95 C essentially all of the Isopar{reg_sign} L was released in three months. Initial curing temperature was found to be very important as slight variations during the first few days affected the final Isopar{reg_sign} L amount released. Short scoping tests at 95 C with solvent containing all components (Isopar

  18. ISOPAR L RELEASE RATES FROM SALTSTONE USING SIMULATED SALT SOLUTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Zamecnik, J; Michael Bronikowski, M; Alex Cozzi, A; Russell Eibling, R; Charles Nash, C

    2008-07-31

    The Modular Caustic-Side Solvent Extraction (CSSX) Unit (MCU) and the Salt Waste Processing Facility (SWPF) will produce a Decontaminated Salt Solution (DSS) that will go to the Saltstone Production Facility (SPF). Recent information indicates that solvent entrainment in the DSS is larger than expected. The main concern is with Isopar{reg_sign} L, the diluent in the solvent mixture, and its flammability in the saltstone vault. If it is assumed that all the Isopar{reg_sign} L is released instantaneously into the vault from the curing grout before each subsequent pour, the Isopar{reg_sign} L in the vault headspace is well mixed, and each pour displaces an equivalent volume of headspace, the maximum concentration of Isopar{reg_sign} L in the DSS to assure 25% of the lower flammable limit is not exceeded has been determined to be about 4 ppm. The amount allowed would be higher if the release from grout were significantly less. The Savannah River National Laboratory was tasked with determining the release of Isopar{reg_sign} L from saltstone prepared with a simulated DSS with Isopar{reg_sign} L concentrations ranging from 50 to 200 mg/L in the salt fraction and with test temperatures ranging from ambient to 95 C. The results from the curing of the saltstone showed that the amount of Isopar{reg_sign} L released versus time can be treated as a percentage of initial amount present; there was no statistically significant dependence of the release rate on the initial concentration. The majority of the Isopar{reg_sign} L that was released over the test duration was released in the first few days. The release of Isopar{reg_sign} L begins immediately and the rate of release decreases over time. At higher temperatures the immediate release rate is larger than at lower temperatures. Initial curing temperature was found to be very important as slight variations during the first few hours or days had a significant effect on the amount of Isopar{reg_sign} L released. Short scoping

  19. Highly Dispersed Palladium Nanoparticles on Functional MWNT Surfaces for Methanol Oxidation in Alkaline Solutions

    Institute of Scientific and Technical Information of China (English)

    WANG zhe; ZHU Zan-Zan; LI You-Xiang; LI Hu-Lin

    2008-01-01

    Palladium nanoparticles were crystallized on 4-aminobenzoic acid monolayer-grafted multi-walled carbon nanotubes (MWNT) by diazotization. The structure and nature of the resulting Pd/MWNT composite were characterized by transmission electron microscopy and X-ray diffraction, the results show that the chemically synthesized Pd nanoparticles were homogeneously dispersed and well-separated from one another on the modified MWNT surfaces. Cyclic voltammogram showed that the Pd-MWNT composite materials performed higher electrocatalytic activity and better long-term stability toward methanol oxidation in alkaline solution than Pd-C. The results imply that the Pd-MWNT composite materials as a promising support material improve the excellent electrocatalytic activity for methanol oxidation greatly. So the Pd/MWNT composites have a good application potential to fuel cells.

  20. Gold leaching with elemental sulfur in alkaline solutions under oxygen pressure

    Institute of Scientific and Technical Information of China (English)

    方兆珩; 石伟

    2003-01-01

    A gold leaching process by using oxidation products of elemental sulfur in alkaline solutions was pro-posed and investigated. A gold concentrate and a residue from an arsenic refractory gold concentrate by acidic oxida-tion leaching were tested. The residue contains 16.3% elemental sulfur and no more elemental sulfur was added intests. For the concentrate elemental sulfur was added before leaching tests. The leaching ratio of gold depends main-ly on the initial equivalent ratio of elemental sulfur to hydroxyl ions, the consumption of oxygen and the reactiontemperature in the process. Analysis of the experimental results shows that thiosulfate is the majority complexingreagent for gold in the process. Over 90% gold was leached from the residue and 82%-87% from the concentrate byusing this process.

  1. Determination of Salt Impurities in MDEA Solution Used in Desulfurization of Highly Sulphurous Natural Gas

    Institute of Scientific and Technical Information of China (English)

    Liu Yucheng; Zhang Bo; Chen Mingyan; Wu Danni; Zhou Zheng

    2015-01-01

    The foaming phenomenon of N-methyldiethanolamine (MDEA) solution used in desulfurization process occurs frequently in the natural-gas puriifcation plant. The foaming phenomenon has a strong impact on operation of the process unit. The salt impurities are the main reason for causing the foaming of MDEA solution, so the full analysis of salt impuri-ties is necessary. A method for comprehensive analysis of salt impurities in MDEA solution used in desulfurization process was established. Anions and non-metallic cations of MDEA solution were determined by different conditions of ion chro-matograph, respectively. Metallic cations of the solution were detected by atomic absorption spectrophotometer with the N2O-C2H2 lfame absorption. The analytical results of salt impurities in the desulfurization solution can provide a theoretical basis for an accurate analysis of the factors affecting the foaming of MDEA to unveil further control measures.

  2. Effects of Various Mixed Salt-Alkaline Stress Conditions on Seed Germination and Early Seedling Growth of Leymus chinensis from Songnen Grassland of China

    Directory of Open Access Journals (Sweden)

    Jixiang LIN

    2014-06-01

    Full Text Available Soil salinization and alkalization always co-occur in grassland ecosystem, but little information exists concerning the mixed effects of salt-alkaline stresses on plants.Leymus chinensis is considered as one of the most promising grass species in Songnen Grassland of Northern China. In this study, we investigated the effects of 30 mixed salt-alkaline conditions (NaCl, Na2SO4, NaHCO3 and Na2CO3; pH 7.10-10.18 and salinity 50-250 mM on seed germination and seedling growth of L. chinensis. The results showed that germination percentage and rate were both decreased with increasing salinity and pH. Nongerminated seeds germinated well after being transferred to distilled water from treatment groups. Shoot and radicle growth were also affacted by salinity, pH and their interactions. However, radicle length decreased more markedly with increasing salinity and pH, and was strongly inhibited when pH reached 8.05. Stepwise regression analysis results showed that salinity was the dominant factor for seed germination under mixed salt-alkaline stress conditions. However, once radicle break through the seed coat, and pH changed into the dominant factor for seedling establishment. These results indicated that mixed salt-alkaline stresses had different impacts on germination and early seedling stages of L. chinensis. A better understanding of the germination and seedling processes should facilitate the effective utilization of this species under such complex environment.

  3. Americium/Lanthanide Separations in Alkaline Solutions for Advanced Nuclear Fuel Cycles

    Energy Technology Data Exchange (ETDEWEB)

    Goff, George S. [Los Alamos National Laboratory; Long, Kristy Marie [Los Alamos National Laboratory; Reilly, Sean D. [Los Alamos National Laboratory; Jarvinen, Gordon D. [Los Alamos National Laboratory; Runde, Wolfgang H. [Los Alamos National Laboratory

    2012-06-11

    Project goals: Can used nuclear fuel be partitioned by dissolution in alkaline aqueous solution to give a solution of uranium, neptunium, plutonium, americium and curium and a filterable solid containing nearly all of the lanthanide fission products and certain other fission products? What is the chemistry of Am/Cm/Ln in oxidative carbonate solutions? Can higher oxidation states of Am be stabilized and exploited? Conclusions: Am(VI) is kinetically stable in 0.5-2.0 M carbonate solutions for hours. Aliquat 336 in toluene has been successfully shown to extract U(VI) and Pu(VI) from carbonate solutions. (Stepanov et al 2011). Higher carbonate concentration gives lower D, SF{sub U/Eu} for = 4 in 1 M K{sub 2}CO{sub 3}. Experiments with Am(VI) were unsuccessful due to reduction by the organics. Multiple sources of reducing organics...more optimization. Reduction experiments of Am(VI) in dodecane/octanol/Aliquat 336 show that after 5 minutes of contact, only 30-40% of the Am(VI) has been reduced. Long enough to perform an extraction. Shorter contact times, lower T, and lower Aliquat 336 concentration still did not result in any significant extraction of Am. Anion exchange experiments using a strong base anion exchanger show uptake of U(VI) with minimal uptake of Nd(III). Experiments with Am(VI) indicate Am sorption with a Kd of 9 (10 minute contact) but sorption mechanism is not yet understood. SF{sub U/Nd} for = 7 and SF{sub U/Eu} for = 19 after 24 hours in 1 M K{sub 2}CO{sub 3}.

  4. Technetium in alkaline, high-salt, radioactive tank waste supernate: Preliminary characterization and removal

    Energy Technology Data Exchange (ETDEWEB)

    Blanchard, D.L. Jr.; Brown, G.N.; Conradson, S.D. [and others

    1997-01-01

    This report describes the initial work conducted at Pacific Northwest National Laboratory to study technetium (Tc) removal from Hanford tank waste supernates and Tc oxidation state in the supernates. Filtered supernate samples from four tanks were studied: a composite double shell slurry feed (DSSF) consisting of 70% from Tank AW-101, 20% from AP-106, and 10% from AP-102; and three complexant concentrate (CC) wastes (Tanks AN-107, SY-101, ANS SY-103) that are distinguished by having a high concentration of organic complexants. The work included batch contacts of these waste samples with Reillex{trademark}-HPQ (anion exchanger from Reilly Industries) and ABEC 5000 (a sorbent from Eichrom Industries), materials designed to effectively remove Tc as pertechnetate from tank wastes. A short study of Tc analysis methods was completed. A preliminary identification of the oxidation state of non-pertechnetate species in the supernates was made by analyzing the technetium x-ray absorption spectra of four CC waste samples. Molybdenum (Mo) and rhenium (Re) spiked test solutions and simulants were tested with electrospray ionization-mass spectrometry to evaluate the feasibility of the technique for identifying Tc species in waste samples.

  5. Reactivity of the cement-bentonite interface with alkaline solutions using transport cells

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Raul [Dpto. Quimica Agricola, Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Campus Cantoblanco, 28049 Madrid (Spain); Cuevas, Jaime [Dpto. Quimica Agricola, Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Campus Cantoblanco, 28049 Madrid (Spain)]. E-mail: jaime.cuevas@uam.es; Sanchez, Laura [Dpto. Quimica Agricola, Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Campus Cantoblanco, 28049 Madrid (Spain); Villa, Raquel Vigil de la [Dpto. Quimica Agricola, Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Campus Cantoblanco, 28049 Madrid (Spain); Leguey, Santiago [Dpto. Quimica Agricola, Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Campus Cantoblanco, 28049 Madrid (Spain)

    2006-06-15

    Clayey formations are considered as suitable host rocks to develop a Deep Geological Repository (DGR) for nuclear wastes. A concrete ring, located between the clayey formation and the bentonite barrier, is needed as structural support for the galleries. This material will act as a source of alkaline fluids when the formation's pore water saturates the system. This investigation evaluates the performance of the concrete-bentonite system by means of both geochemical codes and experimental results. A column made of compacted bentonite from La Serrata (Almeria, Spain) (1.4 g/cm{sup 3}, dry density) was held in contact with an ordinary Portland cement (OPC) mortar. Two alkaline solutions (Ca(OH){sub 2} saturated and NaOH 0.25 M) were injected from the mortar's side at 25, 60 and 120 deg. C. The permeability of the system and the effluent fluid composition were determined periodically. Finally, the solid phase was sampled and analyzed after 1 year of treatment. Ca(OH){sub 2} saturated fluids does not alter the mineralogy over the experiment time scale. NaOH fluids produced minor changes at 60-25 deg. C but at 120 deg. C a thin tobermorite layer of 1.5 mm precipitates in the clay aggregate surfaces at the interface. After this layer, analcime nucleates in heterogeneous patches affecting the whole compacted bentonite probe (2 cm thickness). The use of the PHREEQC code thermodynamic approach predicts the mineralogical transformations. However, it is necessary to introduce kinetic laws and to consider the existence of stagnant zones in the model in order to simulate the heterogeneous spatial alteration observed.

  6. Prediction of solid solution formation in a family of diastereomeric salts. A molecular modeling study

    NARCIS (Netherlands)

    Gervais, C.; Grimbergen, R.F.P.; Markovits, I.; Ariaans, G.J.A.; Kaptein, B.; Bruggink, A.; Broxterman, Q.B.

    2004-01-01

    The possibility of solid solution behavior of diastereomeric salts, containing multiple resolving agents of the same family (Dutch Resolution), is predicted by molecular modeling. Super-cells containing different ratios of resolving agents in the diastereomeric salt are constructed and optimized, an

  7. Oxygen reduction at platinum nanoparticles supported on carbon cryogel in alkaline solution

    Directory of Open Access Journals (Sweden)

    N. R. ELEZOVIC

    2007-07-01

    Full Text Available The oxygen reduction reaction was investigated in 0.1 M NaOH solution, on a porous coated electrode formed of Pt particles supported on carbon cryogel. The Pt/C catalyst was characterized by the X-ray diffraction (XRD, transmission electron microscopy (TEM and cyclic voltammetry techniques. The results demonstrated a successful reduction of Pt to metallic form and homogenous Pt particle size distribution with a mean particle size of about 2.7 nm. The ORR kinetics was investigated by linear sweep polarization at a rotating disc electrode. The results showed the existence of two E – log j regions, usually referred to polycrystalline Pt in acid and alkaline solution. At low current densities (lcd, the Tafel slope was found to be close to –2.3RT/F, while at high current densities (hcd it was found to be close to –2×2.3RT/F. It is proposed that the main path in the ORR mechanism on Pt particles was the direct four-electron process, with the transfer of the first electron as the rate determining step. If the activities are expressed through the specific current densities, a small enhancement of the catalytic activity for Pt/C was observed compared to that of polycrystalline Pt. The effect of the Pt particle size on the electrocatalysis of oxygen reduction was ascribed to the predominant (111 facets of the platinum crystallites.

  8. Stability of ZnMgO oxide in a weak alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Diler, E. [Laboratoire de Magnetisme de Bretagne, EA 4522, CNRS, Universite de Brest, UBO, 6 av. Le Gorgeu, 29285 Brest Cedex (France); Institut de la Corrosion, 220 rue Pierre Rivoalon, 29200 Brest (France); Rioual, S., E-mail: rioual@univ-brest.fr [Laboratoire de Magnetisme de Bretagne, EA 4522, CNRS, Universite de Brest, UBO, 6 av. Le Gorgeu, 29285 Brest Cedex (France); Lescop, B. [Laboratoire de Magnetisme de Bretagne, EA 4522, CNRS, Universite de Brest, UBO, 6 av. Le Gorgeu, 29285 Brest Cedex (France); Thierry, D. [Institut de la Corrosion, 220 rue Pierre Rivoalon, 29200 Brest (France); Rouvellou, B. [Laboratoire de Magnetisme de Bretagne, EA 4522, CNRS, Universite de Brest, UBO, 6 av. Le Gorgeu, 29285 Brest Cedex (France)

    2012-01-31

    Zinc oxide (ZnO) is a chemical compound of great interest used, for example, as photocatalyst in the purification of wastewater or polluted air. However, neither dissolution, nor photo-dissolution of ZnO is negligible: indeed, both processes reduce significantly the efficiency of photocatalysis and then lead to a secondary pollution by free Zn{sup 2+}. In the present study, the stability of ZnMgO thin films in weak alkaline solution is investigated. We demonstrate that the replacement of Zn{sup 2+} ion with Mg{sup 2+} ion results in the production of a Zn{sub 0.84}Mg{sub 0.16}O solid solution, whose stability is higher than that of the ZnO sample. This alloy, thus, constitutes an alternative to the use of ZnO in photocatalysis applications. To gain more insights into the higher resistance of such alloys to the dissolution process, X-Ray photoelectron spectroscopy measurements were performed. They highlighted the role of OH group adsorption in the experimentally observed enhancement of ZnMgO stability.

  9. Location of microseismic swarms induced by salt solution mining

    Science.gov (United States)

    Kinscher, J.; Bernard, P.; Contrucci, I.; Mangeney, A.; Piguet, J. P.; Bigarre, P.

    2015-01-01

    Ground failures, caving processes and collapses of large natural or man-made underground cavities can produce significant socio-economic damages and represent a serious risk envisaged by the mine managements and municipalities. In order to improve our understanding of the mechanisms governing such a geohazard and to test the potential of geophysical methods to prevent them, the development and collapse of a salt solution mining cavity was monitored in the Lorraine basin in northeastern France. During the experiment, a huge microseismic data set (˜50 000 event files) was recorded by a local microseismic network. 80 per cent of the data comprised unusual swarming sequences with complex clusters of superimposed microseismic events which could not be processed through standard automatic detection and location routines. Here, we present two probabilistic methods which provide a powerful tool to assess the spatio-temporal characteristics of these swarming sequences in an automatic manner. Both methods take advantage of strong attenuation effects and significantly polarized P-wave energies at higher frequencies (>100 Hz). The first location approach uses simple signal amplitude estimates for different frequency bands, and an attenuation model to constrain the hypocentre locations. The second approach was designed to identify significantly polarized P-wave energies and the associated polarization angles which provide very valuable information on the hypocentre location. Both methods are applied to a microseismic data set recorded during an important step of the development of the cavity, that is, before its collapse. From our results, systematic spatio-temporal epicentre migration trends are observed in the order of seconds to minutes and several tens of meters which are partially associated with cyclic behaviours. In addition, from spatio-temporal distribution of epicentre clusters we observed similar epicentre migration in the order of hours and days. All together, we

  10. Establishing the potential dependent equilibrium oxide coverage on platinum in alkaline solution and its influence on the oxygen reduction

    DEFF Research Database (Denmark)

    Wiberg, Gustav; Arenz, Matthias

    2012-01-01

    Publication year: 2012 Source:Journal of Power Sources, Volume 217 Gustav K.H. Wiberg, Matthias Arenz The oxidation process of polycrystalline platinum subjected to alkaline solution is re-examined using a combination of cyclic voltammetry and potential hold techniques in Ar, H2 and O2 purged 0.1 M...

  11. 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 temperature...

  12. A Convenient and Environmentally Benign Method of Reducing Aryl Ketones or Aldehydes by Zinc Powder in an Aqueous Alkaline Solution

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Chao-Zhi; YANG,Hui; WU,De-Lin; LU,Guo-Yuan

    2007-01-01

    A convenient and environmentally benign method for reducing the carbonyl group in hydroxy- and amino-9,10-anthracenediones, ortho (or para) acyl phenols and acyl anilines to a methylene group by zinc powder in an aqueous sodium hydroxide solution was reported. Based on theoretical calculations using the density functional theory (DFT), the mechanism of these reduction reactions was postulated. This mechanism can be applied to help predicting the reduced products of aryl ketones (or aldehydes) in an alkaline solution.

  13. Structure of a model salt bridge in solution investigated with 2D-IR spectroscopy

    CERN Document Server

    Huerta-Viga, Adriana; Amirjalayer, Saeed; Woutersen, Sander

    2013-01-01

    Salt bridges are known to be important for the stability of protein conformation, but up to now it has been difficult to study their geometry in solution. Here we characterize the spatial structure of a model salt bridge between guanidinium (Gdm+) and acetate (Ac-) using two-dimensional vibrational (2D-IR) spectroscopy. We find that as a result of salt bridging the infrared response of Gdm+ and Ac- change significantly, and in the 2D-IR spectrum, salt bridging of the molecules appears as cross peaks. From the 2D-IR spectrum we determine the relative orientation of the transition-dipole moments of the vibrational modes involved in the salt bridge, as well as the coupling between them. In this manner we reconstruct the geometry of the solvated salt bridge.

  14. Amino acid salt solutions for carbon dioxide capture

    NARCIS (Netherlands)

    Majchrowicz, Magdalena Elzbieta

    2014-01-01

    Reactive absorption is a common process in the chemical industry and is used, among others, in the treatment of CO2 containing industrial gas streams. The current work was a part of a project with the aim to assess new reactive solvents based on amino acid salts for CO2 removal from industrial gas s

  15. The inhibition of the spongy electrocrystallization of zinc from doped flowing alkaline zincate solutions

    Science.gov (United States)

    Wen, Yue-hua; Cheng, Jie; Zhang, Li; Yan, Xu; Yang, Yu-sheng

    The effects of the presence of additives like lead and tungstate ions in flowing alkaline zincate solutions on suppressing spongy zinc electrogrowth are examined. The results show that the two additives with optimal concentrations in flowing electrolytes can suppress spongy zinc initiation and propagation. And, the two additives can bring about more uniform and compact deposits and, thereby, reduce spongy zinc growth. The influence of lead and tungstate ions on the zinc deposition/dissolution is evaluated by cyclic voltammetry. It also shows that the addition of the two additives is largely a blocking action, and the co-deposition of lead and zinc ions may occur. The performance of the zinc-air flow battery with zinc regeneration electrolysis is determined. It shows that by the addition of 0.6 M Na 2WO 4 or 10 -4 M to 10 -3 M lead, compact or mixed compact-spongy zinc deposits are created and the favorable charge/discharge performance of the battery is achieved with an energy efficiency of approximately 60%.

  16. Production of ultrafine zinc powder from wastes containing zinc by electrowinning in alkaline solution

    Directory of Open Access Journals (Sweden)

    Zhao Youcai

    2013-12-01

    Full Text Available Production of ultrafine zinc powder from industrial wastes by electrowinning in alkaline solution was studied. Stainless steel and magnesium electrodes were used as anode and cathode, respectively. Morphology, size distribution and composition of the Zn particles were characterized by Scanning Electron Microscopy, Laser Particle Size Analyzer, and Inductive Coupled Plasma Emission Spectrometer. The required composition of the electrolyte for ultrafine particles was found to be 25-35 g/L Zn, 200-220 g/L NaOH and 20-40 mg/L Pb. The optimal conditions were a current density of 1000-1200 A/m² and an electrolyte temperature of 30-40 °C. The results indicated that the lead additive exerted a beneficial effect on the refining of the particles, by increasing the cathodic polarization. Through this study, ultrafine zinc powder with a size distribution of around 10 μm could be produced, and considerably high current efficiencies (97-99 % were obtained.

  17. A membraneless microscale fuel cell using non-noble catalysts in alkaline solution

    Science.gov (United States)

    Sung, Woosuk; Choi, Jin-Woo

    This paper presents the development of a novel liquid-based microscale fuel cell using non-noble catalysts in an alkaline solution. The developed fuel cell is based on a membraneless structure. The operational complications of a proton exchange membrane lead the development of a fuel cell with the membraneless structure. Non-noble metals with relatively mild catalytic activity, nickel hydroxide and silver oxide, were employed as anode and cathode catalysts to minimize the effect of cross-reactions with the membraneless structure. Along with nickel hydroxide and silver oxide, methanol and hydrogen peroxide were used as a fuel at anode and an oxidant at cathode. With a fuel mixture flow rate of 200 μl min -1, a maximum output power density of 28.73 μW cm -2 was achieved. The developed fuel cell features no proton exchange membrane, inexpensive catalysts, and simple planar structure, which enables high design flexibility and easy integration of the microscale fuel cell into actual microfluidic systems and portable applications.

  18. CO2 Capture from Flue gas using Amino acid salt solutions

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai

    to storage. Typical solvents for the process are based on aqueous solutions of alkanolamines, such as mono-ethanolamine (MEA), but their use implies economic disadvantages and environmental complications. Amino acid salt solutions have emerged as an alternative to the alkanolamines, partlybecause....../or amino acid salt concentrations. The formation of solids poses challenges, but it also holds the promise for improving the efficiency of the capture process. This project focuses on phase equilibrium experiments of five systems CO2 + amino acid salt + H2O, at conditions relevant for the CO2 capture...... process. Also, attention is given to the chemical compositions of the precipitations, which forms as a result of CO2 absorption into the five amino acid salt solutions. Phase equilibrium data are needed to develop safe and economically viable capture processes. Two different experimental apparatuses were...

  19. Apatite formation on alkaline-treated dense TiO2 coatings deposited using the solution precursor plasma spray process.

    Science.gov (United States)

    Chen, Dianying; Jordan, Eric H; Gell, Maurice; Wei, Mei

    2008-05-01

    A dense titania (TiO2) coating was deposited from an ethanol-based solution containing titanium isopropoxide using the solution precursor plasma spray (SPPS) process. XRD and Raman spectrum analyses confirmed that the coating is exclusively composed of rutile TiO2. SEM micrographs show the as-sprayed coating is dense with a uniform thickness and there are no coarse splat boundaries. The as-sprayed coating was chemically treated in 5M NaOH solution at 80 degrees C for 48 h. The bioactivity of as-sprayed and alkaline-treated coatings was investigated by immersing the coatings in simulated body fluid (SBF) for 14-28 days, respectively. After 28 days immersion, there is a complete layer of carbonate-containing apatite formed on the alkaline-treated TiO2 coating surface, but none formed on the as-sprayed coating.

  20. Effect of alkaline solutions on the tensile properties of glass-polyester pipes

    Directory of Open Access Journals (Sweden)

    Putić Slaviša S.

    2011-01-01

    Full Text Available Construction materials, traditionally used in process equipment, are today successfully replaced by composite materials. Hence, many pipes are made of these materials. The subject of this study was the influence of liquids on the state of stresses and tensile strengths in the longitudinal and circumferential direction of glass-polyester pipes of a definite structure and known fabrication process. These analyses are of great importance for the use of glass-polyester pipes in the chemical industry. The tensile properties (the ultimate tensile strength and the modulus of elasticity were tested and determined for specimens cut out of the pipes; flat specimens for the tensile properties in the longitudinal direction and ring specimens for the tensile properties in the circumferential direction. First, the tension test was performed on virgin samples (without the influence of any liquid, to obtain knowledge about the original tensile properties of the material composite studied. Subsequently, the specimens were soaked in alkaline solutions: sodium hydroxide (strong alkali and ammonium hydroxide (weak alkali. These solutions were selected because of their considerable difference in pH values. The specimens and rings were left for 3, 10, 30 and 60 days in each liquid at room temperature. Then, the samples were tested on tension by the standard testing procedure. A comparison of the obtained results was made based on the pH values of the aggressive media in which the examined material had been soaked, as well as based on the original tensile properties and the number of days of treatment. Micromechanical analyses of sample breakage helped in the elucidation of the influence of the liquids on the structure of the composite pipe and enabled models and mechanisms that produced the change of strength to be proposed.

  1. [A Contrastive Study on Salt-alkaline Resistance and Removal Efficiency of Nitrogen and Phosphorus by Phragmites australis and Typha angustifolia in Coastal Estuary Area].

    Science.gov (United States)

    Chen, You-yuan; Sun, Ping; Chen, Guang-lin; Wang, Ning-ning

    2015-04-01

    The salt and alkali contents were so high that the ecological landscape was depressed in water body of a coastal estuary area. Screening some plants which could not only tolerate saline-alkaline but also effectively remove nitrogen and phosphorus was therefore in urgent need. The tolerance range and removal rate of nitrogen and phosphorus by Phragmites australis and Typha angustifolia under salt and pH stress were investigated by hydroponic experiments. The results showed that Phragmites australis could tolerate at least 10 per thousand salinity and pH 8.5, while Typha angustifolia tolerated 7.5 per thousand salinity and pH 8.0. Combined with the change of the growth and physiological indexes (relative conductivity, proline, chlorophyll and root activity), the salt resistance of Phragmites australis was stronger than that of Typha angustifolia. Under salt stress, the removal rate of ammonia nitrogen of Phragmites australis was higher. The removal rates of nitrate nitrogen and phosphorus of Typha angustifolia were 2.5% and 7.3% higher than those of Phragmites australis in average, respectively, because of the high biomass of Typha angustifolias. The total nitrogen removal rate was equivalent. Under pH stress, the removal rate of ammonia nitrogen and total phosphorus of Phragmites australis was a little higher than that of Typha angustifolia. However, Typha angustifolia had a higher removal rate of total nitrogen, which was 8.2% higher than that of Phragmites australis. All the analysis showed that both Phragmites australis and Typha angustifolia could be used as alternative plants to grow and remove nitrogen and phosphorus in the high salt-alkaline water body in coastal estuary area.

  2. First-principles molecular dynamics modeling of the molten fluoride salt with Cr solute

    Energy Technology Data Exchange (ETDEWEB)

    Nam, H.O.; Bengtson, A.; Vörtler, K.; Saha, S.; Sakidja, R.; Morgan, D., E-mail: ddmorgan@wisc.edu

    2014-06-01

    Fluoride salts and their interactions with metals are of wide interest for the nuclear community. In this work, first-principles molecular dynamics (FPMD) was employed to study both pure molten fluoride salt and fluoride salt with dissolved solute Cr ions (a common corrosion product) at high temperature (823–1423 K). Two types of molten fluoride salts, namely flibe (LiF–BeF{sub 2}) and flinak (LiF–NaF–KF), with the Cr{sup 0}, Cr{sup 2+} and Cr{sup 3+} ions were chosen as a target system for the FPMD modeling. The prediction of thermo-kinetic properties of pure fluoride salt, such as the equilibrium volume, density, bulk modulus, coefficient of thermal expansion, and self-diffusion coefficient, provide useful extensions of existing data and verify the accuracy of the FPMD simulation in modeling of fluoride salts. The FPMD modeling of solute Cr in fluoride salt shows the effect of Cr valence on diffusivity and local structure in the salt.

  3. Length Scale Dependence of the Dynamic Properties of Hyaluronic Acid Solutions in the Presence of Salt

    Energy Technology Data Exchange (ETDEWEB)

    Horkay, Ferenc; Falus, Peter; Hecht, Anne-Marie; Geissler, Erik (CNRS-UMR); (NIH); (ILL)

    2010-12-07

    In solutions of the charged semirigid biopolymer hyaluronic acid in salt-free conditions, the diffusion coefficient D{sub NSE} measured at high transfer momentum q by neutron spin echo is more than an order of magnitude smaller than that determined by dynamic light scattering, D{sub DLS}. This behavior contrasts with neutral polymer solutions. With increasing salt content, D{sub DLS} approaches D{sub NSE}, which is independent of ionic strength. Contrary to theoretical expectation, the ion-polymer coupling, which dominates the low q dynamics of polyelectrolyte solutions, already breaks down at distance scales greater than the Debye-Hueckel length.

  4. Influence of adding salt on ultrasonic atomization in an ethanol-water solution.

    Science.gov (United States)

    Hamai, Koumei; Takenaka, Norimichi; Nanzai, Ben; Okitsu, Kenji; Bandow, Hiroshi; Maeda, Yasuaki

    2009-01-01

    Ethanol was enriched by ultrasonic atomization. Enrichment ratios were increased by adding salt to the ethanol solution. Different enrichment ratios were observed for different types of salts in a range of low ethanol concentrations. The enrichment ratio was significantly improved by adding K(2)CO(3) or (NH(4))(2)SO(4). It is concluded that this is due to enhanced interfacial adsorption of the ethanol. Addition of Na(2)CO(3) to the ethanol solution also enhanced the interfacial adsorption of the ethanol, but the effect was relatively small. Addition of NaCl to the ethanol solution did not enhance the interfacial adsorption of the ethanol.

  5. Lanthanide salts solutions: representation of osmotic coefficients within the binding mean spherical approximation.

    Science.gov (United States)

    Ruas, Alexandre; Moisy, Philippe; Simonin, Jean-Pierre; Bernard, Olivier; Dufrêche, Jean-François; Turq, Pierre

    2005-03-24

    Osmotic coefficients of aqueous solutions of lanthanide salts are described using the binding mean spherical approximation (BIMSA) model based on the Wertheim formalism for association. The lanthanide(III) cation and the co-ion are allowed to form a 1-1 ion pair. Hydration is taken into account by introducing concentration-dependent cation size and solution permittivity. An expression for the osmotic coefficient, derived within the BIMSA, is used to fit data for a wide variety of lanthanide pure salt aqueous solutions at 25 degrees C. A total of 38 lanthanide salts have been treated, including perchlorates, nitrates, and chlorides. For most solutions, good fits could be obtained up to high ionic strengths. The relevance of the fitted parameters has been discussed, and a comparison with literature values has been made (especially the association constants) when available.

  6. Amino acid salt solutions as solvents in CO2 capture from flue gas

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai; Thomsen, Kaj; Stenby, Erling Halfdan

    solutions is their ability to form solid precipitates upon the absorption of CO2. The occurrence of crystallization offers the possibility of increasing the CO2 loading capacity of the solvent. However, precipitation can also have negative effect on the CO2 capture process. The chemical nature of the solid...... loading capacity of aqueous solutions of the potassium salts of selected amino-acids (glycine, taurine, lysine proline, and glutamic acid) were examined, and the relation between the initial amino acid salt concentration and precipitation ability of each solution were determined. Experiments were...... of glycine, taurine, and lysine, while in the case of proline, and glutamic acid, the precipitate was found to be bicarbonate. These results give an important contribution to further understanding the potential of amino acid salt solutions in CO2 capture from flue gas....

  7. Zinc(II) oxide stability in alkaline sodium phosphate solutions at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ziemniak, S.E.; Opalka, E.P.

    1993-04-01

    Zinc oxide (ZnO) is shown to transform into either of two phosphate-containing compounds in relatively dilute alkaline sodium phosphate solutions at elevated temperatures via ZnO(s) + Na{sup +} + H{sub 2}PO{sub 4}{sup {minus}} {r_reversible} NaZnPO{sub 4}(s) + H{sub 2}O or 2 ZnO(s) + H{sub 3}PO{sub 4}(aq) {r_reversible} Zn{sub 2}(OH)PO{sub 4}(s) + H{sub 2}O. X-ray diffraction analyses indicate that NaZnPO{sub 4} possesses an orthorhombic unit cell having lattice parameters a = 8.710 {+-} 0.013, b = 15.175 {+-} 0.010, and c = 8.027 {+-} 0.004 {angstrom}. The thermodynamic equilibria for these reactions were defined in the system ZnO-Na{sub 2}O-P{sub 2}O{sub 5}-H{sub 2}O for Na/P molar ratios between 2.1 and 3. Based on observed reaction threshold values for sodium phosphate concentration and temperature, the standard entropy (S{degrees}) and free energy of formation ({Delta}G{sub f}{degrees}) for NaZnPO{sub 4} were calculated to be 169.0 J/mol-K and {minus}1510.6 kJ/mol, respectively; similar values for Zn{sub 2}(OH)PO{sub 4} (tarbuttite) were 235.9 J/mol-K and {minus}1604.6 kJ/mol. Additions of sodium sulfite and sulfate did not alter the above reactions.

  8. Effect of Organic Inhibitors on Chloride Corrosion of Steel Rebars in Alkaline Pore Solution

    Directory of Open Access Journals (Sweden)

    Marina Cabrini

    2015-01-01

    Full Text Available The inhibition properties of aspartic and lactic acid salts are compared with nitrite ions with regard to their effect on critical chloride concentration. The tests were carried out on carbon steel specimens in simulated pore solutions with initial pH in the range of 12.6 to 13.8. The critical chloride concentrations were estimated through multiple specimen potentiostatic tests at potentials in the usual range for passive rebar in noncarbonated concrete structures. During tests, chloride ions were progressively added until all specimens showed localized attack, obtaining cumulative distribution curves reporting the fraction of corroded specimens as a function of chloride concentration. The presence of the organic inhibitors on the passivity film was detected by IR spectra. The results confirm that 0.1 M aspartate exhibits an inhibiting effect comparable with nitrite ions of the same concentration. Calcium lactate does not increase critical chloride concentration; however it appears to promote the formation of a massive scale, reducing the corrosion propagation.

  9. [Solubilization of nitrobenzene in micellar solutions of Tween 80 and inorganic salts].

    Science.gov (United States)

    Li, Sui; Zhao, Yong-sheng; Xu, Wei; Dai, Ning

    2008-04-01

    The solubilization of nitrobenzene by a nonionic surfactant Tween 80 was investigated at 10 degrees C. Experimental results indicated that the solubility of nitrobenzene in water was greatly enhanced by Tween 80 at surfactant concentration above CMC(critical micelle concentration) and a linear relationship was obtained between surfactant concentration and nitrobenzene concentration from the solubility curve. The molar solubilization ratio (MSR) value was 5.093 and IgKm was 3.499. The solubilization was attributed to the ethoxylation group in Tween 80 micellar. Effect of four inorganic salts such as NaCl, KCl, CaCl2 , MgCl2 on water solubilities of nitrobenzene in Tween 80 micellar solutions was also investigated by a matrix of batch experiments. Mix the Tween 80-inorganic salts at the total mass ratios of 2:1, 5:1 and 10:1. The results show that the inorganic salts at a high concentration( > or = 500 mg x L(-1)) can enhance the solubilization capacities of Tween 80 micellar solution and increase the value of MSR and IgKm . Because of the salting-out effect between the micellar of Tween 80 and inorganic salts, the volume of micelle turns bigger, which may provide larger solubility volume for nitrobenzene. The mixture of nonionic surfactant and inorganic salts can be used in subsurface remediation as a flushing solution.

  10. The rejection of anionic dyes and salt from water solutions using a polypropylene microfilter

    OpenAIRE

    Gomes, Arlindo Caniço; Porter, John Jefferson

    2010-01-01

    Previous work reported by this laboratory showed that inorganic membranes such as stainless steel and ceramic microfilters were capable of rejecting anionic dyes and sodium nitrate from water solutions. It was of interest of see if this were possible with organic membranes such as propylene micrifilters. Experimental data are presented showing that propylene microfilter will reject both salt and Direct Red 2 from aqueous solutions when the conductivity of the solution is below 500 microS. The...

  11. Dynamic flow method to study the CO2 loading capacity of amino acid salt solutions

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai; Stenby, Erling Halfdan; Thomsen, Kaj

    Due to a number of advantages amino acid salt solutions have emerged as alternatives to the alkanolamine solvents for the chemical absorption of CO2 from flue gas. The use of amino acids in CO2 capture is a bio-mimetic process, as it is similar to CO2 binding by proteins in the blood, such as hem......Due to a number of advantages amino acid salt solutions have emerged as alternatives to the alkanolamine solvents for the chemical absorption of CO2 from flue gas. The use of amino acids in CO2 capture is a bio-mimetic process, as it is similar to CO2 binding by proteins in the blood......, such as hemoglobin. Amino acid salt solutions have the same amine functionality as alkanolamines, and are thus expected to behave similar towards CO2 in flue gas. Despite rising interest, few studies have been performed so far on amino acids as CO2 absorbents....

  12. Early containment of high-alkaline solution simulating low-level radioactive waste stream in clay-bearing blended cement

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, A.A. [Westinghouse Hanford Co., Richland, WA (United States); Olson, R.A.; Tennis, P.D. [Northwestern Univ., Evanston, IL (United States). Center for Advanced Cement-Based Materials] [and others

    1995-04-01

    Portland cement blended with fly ash and attapulgite clay was mixed with high-alkaline solution simulating low-level radioactive waste stream at a one-to-one weight ratio. Mixtures were adiabatically and isothermally cured at various temperatures and analyzed for phase composition, total alkalinity, pore solution chemistry, and transport properties as measured by impedance spectroscopy. Total alkalinity is characterized by two main drops. The early one corresponds to a rapid removal of phosphorous, aluminum, sodium, and to a lesser extent potassium solution. The second drop from about 10 h to 3 days is mainly associated with the removal of aluminum, silicon, and sodium. Thereafter, the total alkalinity continues descending, but at a lower rate. All pastes display a rapid flow loss that is attributed to an early precipitation of hydrated products. Hemicarbonate appears as early as one hour after mixing and is probably followed by apatite precipitation. However, the former is unstable and decomposes at a rate that is inversely related to the curing temperature. At high temperatures, zeolite appears at about 10 h after mixing. At 30 days, the stabilized crystalline composition Includes zeolite, apatite and other minor amounts of CaCO{sub 3}, quartz, and monosulfate Impedance spectra conform with the chemical and mineralogical data. The normalized conductivity of the pastes shows an early drop, which is followed by a main decrease from about 12 h to three days. At three days, the permeability of the cement-based waste as calculated by Katz-Thompson equation is over three orders of magnitude lower than that of ordinary portland cement paste. However, a further decrease in the calculated permeability is questionable. Chemical stabilization is favorable through incorporation of waste species into apatite and zeolite.

  13. Continuous electrolytic decarbonation and recovery of a carbonate salt solution from a metal-contaminated carbonate solution.

    Science.gov (United States)

    Kim, Kwang-Wook; Kim, Yeon-Hwa; Lee, Se-Yoon; Lee, Eil-Hee; Song, Kyusuk; Song, Kee-Chan

    2009-11-15

    This work studied the characteristic changes of a continuous electrolytic decarbonation and recovery of a carbonate salt solution from a metal-contaminated carbonate solution with changes of operational variables in an electrolytic system which consisted of a cell-stacked electrolyzer equipped with a cation exchange membrane and a gas absorber. The system could completely recover the carbonate salt solution from a uranyl carbonato complex solution in a continuous operation. The cathodic feed rate could control the carbonate concentration of the recovered solution and it affected the most transient pH drop phenomenon of a well type within the gas absorber before a steady state was reached, which caused the possibility of a CO(2) gas slip from the gas absorber. The pH drop problem could be overcome by temporarily increasing the OH(-) concentration of the cathodic solution flowing down within the gas absorber only during the time required for a steady state to be obtained in the case without the addition of outside NaOH. An overshooting peak of the carbonate concentration in the recovered solution before a steady state was observed, which was ascribed to the decarbonation of the initial solution filled within the stacked cells by a redundant current leftover from the complete decarbonation of the feeding carbonate solution.

  14. Research of measurement errors caused by salt solution temperature drift in surface plasmon resonance sensors

    Institute of Scientific and Technical Information of China (English)

    Yingcai Wu; Zhengtian Gu; YifangYuan

    2006-01-01

    @@ Influence of temperature on measurement of surface plasmon resonance (SPR) sensor was investigated.Samples with various concentrations of NaCI were tested at different temperatures. It was shown that if the affection of temperature could be neglected, measurement precision of salt solution was 0.028 wt.-%.But measurement error of salinity caused by temperature was 0.53 wt.-% in average when the temperature drift was 1 ℃. To reduce the error, a double-cell SPR sensor with salt solution and distilled water flowing respectively and at the same temperature was implemented.

  15. Kinetics of oxidation of odorous sulfur compounds in aqueous alkaline solution with H2O2.

    Science.gov (United States)

    Feliers, C; Patria, L; Morvan, J; Laplanche, A

    2001-10-01

    Sulfur species oxidation is a crucial issue wastewater treatment. The production of sulfur compounds like H2S,CH3SH, C2H5SH, disulfides and dimethyle sulfide generates odorous nuisances for the neighborhood. The oxidation of these species by H2O2 in alkaline solution has been investigated. The results showed that thiols CH3SH and C2H5SH react with H202 only in their dissociated form RS- with rate constants respectively k = 8.81 +/- 0.48 M-1s-1 and 8.37 +/- 0.63 M-1.s-1. Mercaptans oxidation produces 100 % of dimethyldisulfide or diethyldisulfide. The oxidation of disulfides shows a difference of reactivity between H2O2 and HO2- towards sulfur species. Increasing the pH accelerates significantly the reactions in the case of CH3SSCH3. The oxidation rate can be described as: r = k[RSSR][H2O2][RSSR][H2O2] + k[RSSR][HO2-] [RSSR][HO2-] with k[RSSR][H2O2] = 1.2 x 10(-4) +/- 0.2 x 10(-4) M-1s-1 and k[RSSR][HO2-] = 3.4 x 10(-4) +/- 0.6 x 10(-4) M-1.s-1 for CH3SSCH3. Dimethyl sulfide presents a reactivity different from disulfides. The oxidation rate can also be described as: r = k[CH3SCH3][H2O21][CH3SCH3][H2O2] + k[CH3SCH3][HO-] [CH3SCH3][HO2-], however, oxidation rate decreases with pH increase. k[CH3SCH3][H2O2] = 12.8 x 10(-3) +/- 0.96 x 10(-3) M-1.s-1 and k[CH3SCH3][HO2-] = 4 x 10(-3) +/- 0.3 x 10(-3) M-1.s-1.

  16. Temperature and concentration effects on the solvophobic solvation of methane in aqueous salt solutions.

    Science.gov (United States)

    Holzmann, Jörg; Ludwig, Ralf; Geiger, Alfons; Paschek, Dietmar

    2008-12-22

    We perform molecular dynamics (MD) simulations of aqueous salt (NaCl) solutions using the TIP4P-Ew water model (Horn et al., J. Chem. Phys. 2004, 120, 9665) covering broad temperature and concentration ranges extending deeply into the supercooled region. In particular we study the effect of temperature and salt concentration on the solvation of methane at infinite dilution. The salt effect on methane's solvation free energy, solvation enthalpy and entropy, as well as their temperature dependence is found to be semi-quantitatively in accordance with the data of Ben-Naim and Yaacobi (J. Phys. Chem. 1974, 78, 170). To distinguish the influence of local (in close proximity to ions) and global effects, we partition the salt solutions into ion influenced hydration shell regions and bulk water. The chemical potential of methane is systematically affected by the presence of salt in both sub volumes, emphasizing the importance of the global volume contraction due to electrostriction effects. This observation is correlated with systematic structural alterations similar to water under pressure. The observed electrostriction effects are found to become increasingly pronounced under cold (supercooled) conditions. We find that the influence of temperature and salt induced global density changes on the solvation properties of methane is well recovered by simple scaling relation based on predictions of the information theory model of Garde et al. (Phys. Rev. Let. 1999, 77, 4966).

  17. Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt

    Directory of Open Access Journals (Sweden)

    Palash Sanphui

    2014-03-01

    Full Text Available Acemetacin (ACM is a non-steroidal anti-inflammatory drug (NSAID, which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM, isonicotinamide (INA, and picolinamide (PAM], caprolactam (CPR, p-aminobenzoic acid (PABA, and piperazine (PPZ. The structures of an ACM–INA cocrystal and a binary adduct ACM–PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM–PAM and ACM–CPR, and the piperazine salt ACM–PPZ were solved from high-resolution powder X-ray diffraction data. The ACM–INA cocrystal is sustained by the acid...pyridine heterosynthon and N—H...O catemer hydrogen bonds involving the amide group. The acid...amide heterosynthon is present in the ACM–PAM cocrystal, while ACM–CPR contains carboxamide dimers of caprolactam along with acid–carbonyl (ACM hydrogen bonds. The cocrystals ACM–INA, ACM–PAM and ACM–CPR are three-dimensional isostructural. The carboxyl...carboxyl synthon in ACM–PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM–PPZ salt and ACM–nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM–PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable

  18. Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt.

    Science.gov (United States)

    Sanphui, Palash; Bolla, Geetha; Nangia, Ashwini; Chernyshev, Vladimir

    2014-03-01

    Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR), p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACM-INA cocrystal and a binary adduct ACM-PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM-PAM and ACM-CPR, and the piperazine salt ACM-PPZ were solved from high-resolution powder X-ray diffraction data. The ACM-INA cocrystal is sustained by the acid⋯pyridine heterosynthon and N-H⋯O catemer hydrogen bonds involving the amide group. The acid⋯amide heterosynthon is present in the ACM-PAM cocrystal, while ACM-CPR contains carboxamide dimers of caprolactam along with acid-carbonyl (ACM) hydrogen bonds. The cocrystals ACM-INA, ACM-PAM and ACM-CPR are three-dimensional isostructural. The carboxyl⋯carboxyl synthon in ACM-PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM-PPZ salt and ACM-nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM-PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine salt of acemetacin exhibits superior

  19. Ion aggregation in high salt solutions. VI. Spectral graph analysis of chaotropic ion aggregates

    Science.gov (United States)

    Choi, Jun-Ho; Cho, Minhaeng

    2016-11-01

    Carrying out molecular dynamics simulations and graph theoretical analyses of high salt solutions, and comparing numerically calculated vibrational spectroscopic properties of water with femtosecond IR pump-probe experimental data, we have recently found that ions in high salt solutions can form two morphologically different ion aggregate structures. In the cases of NaCl solutions, Na+ and Cl- tend to form compact cluster-like ion aggregate in high NaCl solutions. In contrast, K+ and SCN- form spatially extended network-like ion aggregates that also exhibit a percolating network behavior. Interestingly, a variety of graph theoretical properties of ion network in high KSCN solutions were found to be very similar to those of water H-bonding network. It was shown that spatially extended ion networks in high KSCN solutions are completely intertwined with water H-bonding networks, which might be the key to understand the high solubility of thiocyanate salts in water. Here, we further consider two salts that have been extensively studied experimentally by using femtosecond IR pump-probe technique, which are NaClO4 and NaBF4. Note that ClO4 - and BF4 - are well-known chaotropic ions that have been believed to behave as water structure breaker. To understand how such chaotropic ions affect water H-bonding structure, we carried out spectral graph analyses of molecular dynamics simulation data of these aqueous solutions. Graph spectra and degree distribution of ion aggregates formed in high NaBF4 and NaClO4 solutions show that these chaotropic anions also have a strong propensity to form ion networks. The fact that salts containing chaotropic ions like SCN-, BF4 - , and ClO4 - have very high solubility limits in water could then be related to our observation that these chaotropic anions with counter cations in high salt solutions are capable of forming intricate ion networks intertwined with water H-bonding networks. We anticipate that the present graph theoretical analysis

  20. Effects of applied potential on the stress corrosion cracking behavior of 7003 aluminum alloy in acid and alkaline chloride solutions

    Science.gov (United States)

    Zhang, Xiao-yan; Song, Ren-guo; Sun, Bin; Lu, Hai; Wang, Chao

    2016-07-01

    Potentiodynamic polarization tests and slow strain rate test (SSRT) in combination with fracture morphology observations were conducted to investigate the stress corrosion cracking (SCC) behavior of 7003 aluminum alloy (AA7003) in acid and alkaline chloride solutions under various applied potentials ( E a). The results show that AA7003 is to a certain extent susceptible to SCC via anodic dissolution (AD) at open-circuit potential (OCP) and is highly susceptible to hydrogen embrittlement (HE) at high negative E a in the solutions with pH levels of 4 and 11. The susceptibility increases with negative shift in the potential when E a is less than -1000 mV vs. SCE. However, the susceptibility distinctly decreases because of the inhibition of AD when E a is equal to -1000 mV vs. SCE. In addition, the SCC susceptibility of AA7003 in the acid chloride solution is higher than that in the alkaline solution at each potential. Moreover, the effect of hydrogen on SCC increases with increasing hydrogen ion concentration.

  1. A new class of draw solutions for minimizing reverse salt flux to improve forward osmosis desalination.

    Science.gov (United States)

    Nguyen, Hau Thi; Nguyen, Nguyen Cong; Chen, Shiao-Shing; Ngo, Huu Hao; Guo, Wenshan; Li, Chi-Wang

    2015-12-15

    The applications of forward osmosis (FO) have been hindered because of the lack of an optimal draw solution. The reverse salt flux from the draw solution not only reduces the water flux but also increases the cost of draw solute replenishment. Therefore, in this study, Tergitol NP7 and NP9 with a long straight carbon chain and low critical micelle concentration (CMC) were coupled with highly charged ethylenediaminetetraacetic acid (EDTA) as an innovative draw solution to minimize reverse salt diffusion in FO for the first time. The results showed that the lowest reverse salt flux of 0.067 GMH was observed when 0.1M EDTA-2Na coupled with 15mM NP7 was used as a draw solution and deionized water was used as a feed solution in FO mode (active layer facing with the feed solution). This is due to the hydrophobic interaction between the tails of NP7 and the FO membrane, thus creating layers on the membrane surface and constricting the FO membrane pores. Moreover, 1M EDTA-2Na coupled with 15mM NP7 is promising as an optimal draw solution for brackish water and sea water desalination. Average water fluxes of 7.68, 6.78, and 5.95 LMH were achieved when brackish water was used as a feed solution (5, 10, and 20g/L NaCl), and an average water flux of 3.81 LMH was achieved when sea water was used as a feed solution (35g/L NaCl). The diluted draw solution was recovered using a nanofiltration (NF-TS80) membrane with a high efficiency of 95% because of the high charge and large size of the draw solution.

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

    Energy Technology Data Exchange (ETDEWEB)

    Husar, Richard

    2015-08-20

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

  3. Rheological properties of salt-tolerant HPAM solutions with ultrahigh molecular weight

    Institute of Scientific and Technical Information of China (English)

    张敏革; 张吕鸿; 姜斌; 李鑫钢

    2008-01-01

    The rheological properties of salt-tolerant partially hydrolyzed polyacrylamide(HPAM)solutions with molecular of 2.5×107 g/mol at different concentrations were measured in steady-state shear flow mode by Haake Rheostress 150 rheometer.Three constitutive equations(Oldroyd four constant model,Guesekus model and FENE-P model) were used for describing the apparent viscosity and first normal stress difference.The apparent viscosity of salt-tolerant HPAM solutions appears a first Newtonian zone when the shear rate is approximately lower than 0.2 s-1.At high shear rate,the HPAM solutions show shear-thinning and elasticity.The results show that the FENE-P model has the best agreement between theoretical and experimental data within the available shear rate range.The material parameters are useful for numerical analysis of polymer solution flow fields.

  4. Catalysis and stability of an alkaline protease from a haloalkaliphilic bacterium under non-aqueous conditions as a function of pH, salt and temperature.

    Science.gov (United States)

    Pandey, Sandeep; Rakholiya, Kalpna D; Raval, Vikram H; Singh, Satya P

    2012-09-01

    A haloalkaliphilic bacterium, isolated from Coastal Gujarat (India) was identified as Oceanobacillus sp. (GQ162111) based on 16S rRNA gene sequence. The organism grew and secreted extra cellular protease in presence of various organic solvents. At 30% (v/v) concentration of hexane, heptane, isooctane, dodecane and decane, significant growth and protease production was evident. The alkaline protease was purified in a single step on phenyl sepharose 6 FF with 28% yield. The molecular mass as judged by SDS-PAGE was 30 kDa. The temperature optimum of protease was 50°C and the enzyme retained 70% activity in 10% (v/v) isooctane. Effect of salt and pH was investigated in combination to assess the effect of isooctane. In organic solvents, the enzyme was considerably active at pH 8-11, with optimum activity at pH 10. Salt at 2 M was optimum for activity and enzyme maintained significant stability up to 18 h even at 3 M salt concentration. Patters of growth, protease production, catalysis and stability of the enzyme are presented. The study resumes significance as limited information is available on the interaction of haloalkaliphilic bacteria and their enzymes with organic solvents.

  5. Additional disinfection with a modified salt solution in a root canal model

    NARCIS (Netherlands)

    S.V. van der Waal; C.A.M. Oonk; S.H. Nieman; P.R. Wesselink; J.J. de Soet; W. Crielaard

    2015-01-01

    Objectives The aim of this study is to investigate the disinfecting properties of a modified salt solution (MSS) and calcium hydroxide (Ca(OH)2) in a non-direct-contact ex-vivo model. Methods Seventy-four single-canal roots infected with Enterococcus faecalis were treated with 1% sodium hypochlorite

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

    OpenAIRE

    Zuber, A; R. F. Checoni; M. Castier

    2015-01-01

    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 comprise...

  7. Methods for predicting properties and tailoring salt solutions for industrial processes

    Science.gov (United States)

    Ally, Moonis R.

    1993-01-01

    An algorithm developed at Oak Ridge National Laboratory accurately and quickly predicts thermodynamic properties of concentrated aqueous salt solutions. This algorithm is much simpler and much faster than other modeling schemes and is unique because it can predict solution behavior at very high concentrations and under varying conditions. Typical industrial applications of this algorithm would be in manufacture of inorganic chemicals by crystallization, thermal storage, refrigeration and cooling, extraction of metals, emissions controls, etc.

  8. Halotolerant cyanobacterium Aphanothece halophytica contains NapA-type Na+/H+ antiporters with novel ion specificity that are involved in salt tolerance at alkaline pH.

    Science.gov (United States)

    Wutipraditkul, Nuchanat; Waditee, Rungaroon; Incharoensakdi, Aran; Hibino, Takashi; Tanaka, Yoshito; Nakamura, Tatsunosuke; Shikata, Masamitsu; Takabe, Tetsuko; Takabe, Teruhiro

    2005-08-01

    Aphanothece halophytica is a halotolerant alkaliphilic cyanobacterium which can grow at NaCl concentrations up to 3.0 M and at pH values up to 11. The genome sequence revealed that the cyanobacterium Synechocystis sp. strain PCC 6803 contains five putative Na+/H+ antiporters, two of which are homologous to NhaP of Pseudomonas aeruginosa and three of which are homologous to NapA of Enterococcus hirae. The physiological and functional properties of NapA-type antiporters are largely unknown. One of NapA-type antiporters in Synechocystis sp. strain PCC 6803 has been proposed to be essential for the survival of this organism. In this study, we examined the isolation and characterization of the homologous gene in Aphanothece halophytica. Two genes encoding polypeptides of the same size, designated Ap-napA1-1 and Ap-napA1-2, were isolated. Ap-NapA1-1 exhibited a higher level of homology to the Synechocystis ortholog (Syn-NapA1) than Ap-NapA1-2 exhibited. Ap-NapA1-1, Ap-NapA1-2, and Syn-NapA1 complemented the salt-sensitive phenotypes of an Escherichia coli mutant and exhibited strongly pH-dependent Na+/H+ and Li+/H+ exchange activities (the highest activities were at alkaline pH), although the activities of Ap-NapA1-2 were significantly lower than the activities of the other polypeptides. Only one these polypeptides, Ap-NapA1-2, complemented a K+ uptake-deficient E. coli mutant and exhibited K+ uptake activity. Mutagenesis experiments suggested the importance of Glu129, Asp225, and Asp226 in the putative transmembrane segment and Glu142 in the loop region for the activity. Overexpression of Ap-NapA1-1 in the freshwater cyanobacterium Synechococcus sp. strain PCC 7942 enhanced the salt tolerance of cells, especially at alkaline pH. These findings indicate that A. halophytica has two NapA1-type antiporters which exhibit different ion specificities and play an important role in salt tolerance at alkaline pH.

  9. On-site production of a dialysis bath from dry salts. Results of solute concentration control by routine clinical chemistry

    OpenAIRE

    Beige, Joachim; Lutter, Steffen; Martus, Peter

    2012-01-01

    Background. Dialysis bath production, at least in Europe, is currently based on pre-produced aqueous solutions of dialysis salts (concentrate), which are re-handled by dialysis machines to deliver the final dialysate concentrations. Because of the logistics of aqueous solution creation, a large amount of transportation capacity is needed. Therefore, we changed this process to use pre-produced dry salt containers and to undertake in-clinic dissolution of salts and concentration production. Bec...

  10. Explicit-water theory for the salt-specific effects and Hofmeister series in protein solutions

    Science.gov (United States)

    Kalyuzhnyi, Yuriy V.; Vlachy, Vojko

    2016-06-01

    Effects of addition of salts on stability of aqueous protein solutions are studied theoretically and the results are compared with experimental data. In our approach, all the interacting species, proteins, ions, and water molecules, are accounted for explicitly. Water molecules are modeled as hard spheres with four off-center attractive square-well sites. These sites serve to bind either another water or to solvate the ions or protein charges. The ions are represented as charged hard spheres, and decorated by attractive sites to allow solvation. Spherical proteins simultaneously possess positive and negative groups, represented by charged hard spheres, attached to the surface of the protein. The attractive square-well sites, mimicking the protein-protein van der Waals interaction, are located on the surface of the protein. To obtain numerical results, we utilized the energy route of Wertheim's associative mean spherical approximation. From measurable properties, we choose to calculate the second virial coefficient B2, which is closely related to the tendency of proteins to aggregate and eventually crystalize. Calculations are in agreement with experimental trends: (i) For low concentration of added salt, the alkali halide salts follow the inverse Hofmeister series. (ii) At higher concentration of added salt, the trend is reversed. (iii) When cations are varied, the salts follow the direct Hofmeister series. (iv) In contrast to the colloidal theories, our approach correctly predicts the non-monotonic behavior of B2 upon addition of salts. (v) With respect to anions, the theory predicts for the B2 values to follow different sequences below and above the iso-ionic point, as also confirmed experimentally. (vi) A semi-quantitative agreement between measured and calculated values for the second virial coefficient, as functions of pH of solution and added salt type and concentration, is obtained.

  11. Processing method for molten salt waste

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Shuichi; Sawa, Toshio; Hoshikawa, Tadahiro; Suzuoki, Akira

    1999-01-06

    The present invention concerns a processing method for selectively adsorbing and removing radioactive metal ingredients contained in high temperature molten salts by an inorganic ion exchanger and separating radioactive metal ingredients from the molten salts as high level radioactive wastes upon reprocessing of spent nuclear fuels by using molten salts. The molten salts occluded in the inorganic ion exchanger are desorbed with highly purified water. Successively, saturation adsorbed radioactive metal ingredients are desorbed by an aqueous solution of alkali metal salt or an aqueous solution of alkaline earth metal salt. The desorbed molten salts and radioactive metal ingredients are formed into at least two kinds of radioactive waste solidification materials depending on each of radioactivity level. As the inorganic ion exchanger, at least one of aluminosilicate and hydroxides is used. Then, molten salt wastes generated upon a dry-type reprocessing can be processed as a stable borosilicate glass solidification material or as a similar homogeneous solid material. (T.M.)

  12. [Isolation and functional analysis of GsTIFY11b relevant to salt and alkaline stress from Glycine soja].

    Science.gov (United States)

    Zhu, Dan; Bai, Xi; Zhu, Yan-Ming; Cai, Hua; Li, Yong; Ji, Wei; Chen, Chao; An, Lin; Zhu, Yi

    2012-02-01

    Using homologous cloning and RT-PCR technology, we isolated a novel TIFY family gene, GsTIFY11b, from Glycine soja L. G07256, a species that is tolerant to saline and alkaline environments. Phylogenetic analysis indicated that GsTIFY11b was closely related to AtTIFY11a with 56% similarity in amino acid identity. Protein sequence analysis showed that GsTIFY11b protein also had conserved TIFY domain, N-terminal domain, and a C-terminal Jas motif. Quantitative realtime PCR analysis indicated that the expression of GsTIFY11b was induced by both saline and alkaline stresses. Two homozygous GsTIFY11b over-expressing transgenic Arabidopsis lines were obtained. Phenotypic analysis of the transgenic and wild-type Arabidopsis indicated that over-expressing GsTIFY11b in Arabidopsis did not enhance plant tolerance to saline and alkaline stresses, whereas it showed an increased sensitivity to saline stress during seed germination and seedling development. Expression analysis of saline stress response marker genes in transgenic and wild-type plants under stress condition indicated that GsTIFY11b regulated the expression of RD29B, KIN1, and DREB. The transient expression of a GsTIFY11b-GFP fusion protein in onion epidermal cells showed that GsTIFY11b was localized to the nucleus, suggesting a role as a transcriptional regulator in the saline stress response pathway.

  13. The role of the interaction between oxygen and catechol in the pitting corrosion of steel in alkaline sulfide solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, S.; Kelly, R.G. [Univ. of Virginia, Charlottesville, VA (United States)

    1995-12-01

    Black liquor corrosivity is shown to depend on the interaction of the chemical species present. Specifically, an interaction between oxygen and 1,2-dihydroxybenzene compounds (catechols) in alkaline sulfide solutions leads to a distinct increase in the severity of the attack. This increased corrosivity is explained in terms of the oxidation of catechol leading to increased open circuit potentials for steel. The importance of the ratio of sulfide concentration to hydroxyl concentration in the initiation of pitting is stressed. The possible role of catechol in stabilizing metastable pits is also discussed.

  14. A preliminary study of the electro-oxidation of L-ascorbic acid on polycrystalline silver in alkaline solution

    Science.gov (United States)

    Majari Kasmaee, L.; Gobal, F.

    Electrochemical oxidation of L-ascorbic acid on polycrystalline silver in alkaline aqueous solutions is studied by cyclic voltammetry (CV), chronoamperometry (CA) and impedance spectroscopy (IS). The anodic electro-oxidation starts at -500 mV versus SCE and shows continued anodic oxidation in the cathodic half cycle in the CV regime signifying slowly oxidizing adsorbates. Diffusion coefficient of ascorbate ion measured under both voltammetric regimes is around 1.4 × 10 -5 cm 2 s -1. Impedance spectroscopy measures the capacitances associated with double layer and adsorption around 50 μF cm -2 and 4 mF cm -2 as well as the adsorption and decomposition resistances (rates).

  15. Modeling Solute Thermokinetics in LiCI-KCI Molten Salt for Nuclear Waste Separation

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, Dane; Eapen, Jacob

    2013-10-01

    Recovery of actinides is an integral part of a closed nuclear fuel cycle. Pyrometallurgical nuclear fuel recycling processes have been developed in the past for recovering actinides from spent metallic and nitride fuels. The process is essentially to dissolve the spent fuel in a molten salt and then extract just the actinides for reuse in a reactor. Extraction is typically done through electrorefining, which involves electrochemical reduction of the dissolved actinides and plating onto a cathode. Knowledge of a number of basic thermokinetic properties of salts and salt-fuel mixtures is necessary for optimizing present and developing new approaches for pyrometallurgical waste processing. The properties of salt-fuel mixtures are presently being studied, but there are so many solutes and varying concentrations that direct experimental investigation is prohibitively time consuming and expensive (particularly for radioactive elements like Pu). Therefore, there is a need to reduce the number of required experiments through modeling of salt and salt-fuel mixture properties. This project will develop first-principles-based molecular modeling and simulation approaches to predict fundamental thermokinetic properties of dissolved actinides and fission products in molten salts. The focus of the proposed work is on property changes with higher concentrations (up to 5 mol%) of dissolved fuel components, where there is still very limited experimental data. The properties predicted with the modeling will be density, which is used to assess the amount of dissolved material in the salt; diffusion coefficients, which can control rates of material transport during separation; and solute activity, which determines total solubility and reduction potentials used during electrorefining. The work will focus on La, Sr, and U, which are chosen to include the important distinct categories of lanthanides, alkali earths, and actinides, respectively. Studies will be performed using LiCl-KCl salt

  16. Mathematics of the total alkalinity-pH equation - pathway to robust and universal solution algorithms: the SolveSAPHE package v1.0.1

    Science.gov (United States)

    Munhoven, G.

    2013-08-01

    The total alkalinity-pH equation, which relates total alkalinity and pH for a given set of total concentrations of the acid-base systems that contribute to total alkalinity in a given water sample, is reviewed and its mathematical properties established. We prove that the equation function is strictly monotone and always has exactly one positive root. Different commonly used approximations are discussed and compared. An original method to derive appropriate initial values for the iterative solution of the cubic polynomial equation based upon carbonate-borate-alkalinity is presented. We then review different methods that have been used to solve the total alkalinity-pH equation, with a main focus on biogeochemical models. The shortcomings and limitations of these methods are made out and discussed. We then present two variants of a new, robust and universally convergent algorithm to solve the total alkalinity-pH equation. This algorithm does not require any a priori knowledge of the solution. SolveSAPHE (Solver Suite for Alkalinity-PH Equations) provides reference implementations of several variants of the new algorithm in Fortran 90, together with new implementations of other, previously published solvers. The new iterative procedure is shown to converge from any starting value to the physical solution. The extra computational cost for the convergence security is only 10-15% compared to the fastest algorithm in our test series.

  17. Solution behavior and activity of a halophilic esterase under high salt concentration.

    Directory of Open Access Journals (Sweden)

    Lang Rao

    Full Text Available BACKGROUND: Halophiles are extremophiles that thrive in environments with very high concentrations of salt. Although the salt reliance and physiology of these extremophiles have been widely investigated, the molecular working mechanisms of their enzymes under salty conditions have been little explored. METHODOLOGY/PRINCIPAL FINDINGS: A halophilic esterolytic enzyme LipC derived from archeaon Haloarcula marismortui was overexpressed from Escherichia coli BL21. The purified enzyme showed a range of hydrolytic activity towards the substrates of p-nitrophenyl esters with different alkyl chains (n = 2-16, with the highest activity being observed for p-nitrophenyl acetate, consistent with the basic character of an esterase. The optimal esterase activities were found to be at pH 9.5 and [NaCl] = 3.4 M or [KCl] = 3.0 M and at around 45 degrees C. Interestingly, the hydrolysis activity showed a clear reversibility against changes in salt concentration. At the ambient temperature of 22 degrees C, enzyme systems working under the optimal salt concentrations were very stable against time. Increase in temperature increased the activity but reduced its stability. Circular dichroism (CD, dynamic light scattering (DLS and small angle neutron scattering (SANS were deployed to determine the physical states of LipC in solution. As the salt concentration increased, DLS revealed substantial increase in aggregate sizes, but CD measurements revealed the maximal retention of the alpha-helical structure at the salt concentration matching the optimal activity. These observations were supported by SANS analysis that revealed the highest proportion of unimers and dimers around the optimal salt concentration, although the coexistent larger aggregates showed a trend of increasing size with salt concentration, consistent with the DLS data. CONCLUSIONS/SIGNIFICANCE: The solution alpha-helical structure and activity relation also matched the highest proportion of enzyme unimers

  18. Effect of perfusion of bile salts solutions into the oesophagus of hiatal hernia patients and controls.

    Science.gov (United States)

    Bachir, G S; Collis, J L

    1976-01-01

    Tests of the response to perfusion of the oesophagus were made in 54 patients divided into three groups. Group I consisted of patients with symptomatic hiatal hernia, group II hiatal hernia patients with peptic stricture, and group III normal individuals. Each individual oesophagus was perfused at a rate of 45-65 drops per minute over 25 minutes with six solutions: normal saline, N/10 HCl, taurine conjugates of bile salts in normal saline, taurine conjugates of bile salts in N/10 HCl, glycine conjugates of bile salts in normal saline, and taurine and glycine conjugates in a ratio of 1 to 2 in normal saline. It was found that acidified taurine solutions were more irritating than acid alone. With a 2mM/l solution of taurine in acid, symptoms are produced even in controls. With a 1 mM/l solution of the same conjugates, the majority of normal people feel slight heartburn or nothing, and therefore perfusion into the oesophagus of such a solution could be used as a test for oesophagitis. PMID:941112

  19. Fourteen-year survival of Pseudomonas cepacia in a salts solution preserved with benzalkonium chloride.

    Science.gov (United States)

    Geftic, S G; Heymann, H; Adair, F W

    1979-01-01

    A strain of Pseudomonas cepacia that survived for 14 years (1963 to 1977) as a contaminant in an inorganic salt solution which contained commercial 0.05% benzalkonium chloride (CBC) as an antimicrobial preservative, was compared to a recent clinical isolate of P. cepacia. Ammonium acetate was present in the concentrated stock CBC solution, and served as a carbon and nitrogen source for growth when carried over into the salts solution with the CBC. The isolate's resistance to pure benzalkonium chloride was increased step-wise to a concentration of 16%. Plate counts showed 4 x 10(3) colony-forming units per ml in the salts solution. Comparison of growth rates, mouse virulence, antibiotics resistance spectra, and substrate requirements disclosed no differences between the contaminant and a recently isolated clinical strain of P. cepacia. The results indicate that it is critical that pharmaceutical solutions containing benzalkonium chloride as an antimicrobial preservative be formulated without extraneous carbon and nitrogen sources or be preserved with additional antimicrobial agents. PMID:453827

  20. MD simulations of the formation of stable clusters in mixtures of alkaline salts and imidazolium-based ionic liquids.

    Science.gov (United States)

    Méndez-Morales, Trinidad; Carrete, Jesús; Bouzón-Capelo, Silvia; Pérez-Rodríguez, Martín; Cabeza, Óscar; Gallego, Luis J; Varela, Luis M

    2013-03-21

    Structural and dynamical properties of room-temperature ionic liquids containing the cation 1-butyl-3-methylimidazolium ([BMIM](+)) and three different anions (hexafluorophosphate, [PF6](-), tetrafluoroborate, [BF4](-), and bis(trifluoromethylsulfonyl)imide, [NTf2](-)) doped with several molar fractions of lithium salts with a common anion at 298.15 K and 1 atm were investigated by means of molecular dynamics simulations. The effect of the size of the salt cation was also analyzed by comparing these results with those for mixtures of [BMIM][PF6] with NaPF6. Lithium/sodium solvation and ionic mobilities were analyzed via the study of radial distribution functions, coordination numbers, cage autocorrelation functions, mean-square displacements (including the analysis of both ballistic and diffusive regimes), self-diffusion coefficients of all the ionic species, velocity and current autocorrelation functions, and ionic conductivity in all the ionic liquid/salt systems. We found that lithium and sodium cations are strongly coordinated in two different positions with the anion present in the mixture. Moreover, [Li](+) and [Na](+) cations were found to form bonded-like, long-lived aggregates with the anions in their first solvation shell, which act as very stable kinetic entities within which a marked rattling motion of salt ions takes place. With very long MD simulation runs, this phenomenon is proved to be on the basis of the decrease of self-diffusion coefficients and ionic conductivities previously reported in experimental and computational results.

  1. The solubility and properties of a purified ichthyocol in salt solutions of neutral pH.

    Science.gov (United States)

    GALLOP, P M; SEIFTER, S; MEILMAN, E

    1957-07-25

    1. Purified citrate-extracted ichthyocol obtained from carp swim bladders has been further characterized with respect to its content of certain amino acids and carbohydrate substances. 2. The degree of solubilization or dispersion of ichthyocol by solutions of certain salts maintained in the range of neutral pH and at a temperature of 0-2 degrees C. has been determined. 3. While a number of salts of monovalent cations had no significant solubilizing effects on ichthyocol, ammonium chloride in a concentration of 1 M did cause solution of the protein. 4. Sodium thiosulfate in a range of concentrations caused the solubilization of ichthyocol but was most effective in an intermediate concentration of 0.25 M. 5. Several salts of divalent cations, in particular the chlorides of calcium, magnesium, and barium, and magnesium thiosulfate in concentrations ranging from 0.3 to 1 M caused the immediate and complete solubilization of the ichthyocol. 6. Solutions of ichthyocol in calcium chloride, magnesium chloride, and sodium thiosulfate buffered or adjusted to pH 7.0, were studied with respect to intrinsic viscosity of the protein, optical rotation, ultracentrifugal sedimentation, and reconstitution into fibers. It was found in each case that the original characteristics of the collagen, as determined previously in acid solution, were maintained when the protein was dissolved in salt solutions of neutral pH. No evidence of denaturation or gelatinization could be found when ichthyocol was solubilized under the stated conditions. 7. Collagen in neutral solution with sodium thiosulfate, calcium chloride, or magnesium chloride was not attacked by trypsin as determined viscometrically at 20.0 degrees C., but was rapidly degraded by a purified bacterial collagenase.

  2. Changes in Soil Solution Cu and Zn Follogwing Application of Alkaline Stabilised Sewage Sludge and Gamma-Irradiation

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    A glasshouse pot experiment was conducted to study study changes in the solubility of copper and zinc in the soil-plant system follwing heavy application of sewage sludge and partial sterilisation of the sludge/soil mixture,A silghtly acid sandy loam was mixed with alkaline stabilised and composted urban sewage sludge solids ('Agri-Soil',180 t hm-2),and the soil/sludge mixture was γ-irradiated( 10 kGy).The contrasts without the application of sewage sludge and γ-irradiation were also included in the experiment.Perennial ryegrass(Lolium perenne,cv.Magella) was grown on irradiated and unirradiated soils for 50 days. Soil solution samples were obtained using soil suction samplers immediately before plant transplantation and every ten days thereafter.The soil solution smmples were used directly for determination of Cu and Zn,together with pH,electrical conductivity(EC) and absorbance at wavelength 360 nm(A360).Application of Agri-Soil led to a substantial increase in dissolved Cu and a significant derease in dissolved Zn in the soil solution and thess effect were accompanied by increased soil solution pH ,EC and A360 ,The alkaline sludge product(Agri-Soil) in combination with γ-irradiation also led to pronounced elevtion of Cu and A360 but a marked decline in EC, indicatig an increase in dissolvedorganic compounds and a decrease in the ionic strength of the soil solution ,The dissolved Cu and Zn,EC and A360 usually decreased while the ph increased fter plant growth for 50 days.

  3. Mössbauer spectroscopic studies of frozen aqueous solutions of Fe3+ salts

    DEFF Research Database (Denmark)

    Mørup, Steen; Knudsen, J. E.; Nielsen, M. K.

    1976-01-01

    Frozen aqueous solutions (FAS) of Fe3+ salts have been investigated by use of Mössbauer spectroscopy in order to study the conditions for formation of glasses. A general discussion of spin–spin relaxation in glasses is given, and we discuss how changes in the spin–spin relaxation time can...... concentration of the solution increases. At low temperatures the crystallization terminates and the remaining liquid solidifies into a glass. During exposure at 200 K, the dilute samples change irreversibly. This is discussed in terms of a metastable phase diagram. The properties of frozen solutions with other...

  4. Iron salts in solid state and in frozen solutions as dosimeters for low irradiation temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, T. [Facultad de Quimica UNAM, Ciudad Universitaria, D.F. Mexico (Mexico); Lartigue, J. [Facultad de Quimica UNAM, Ciudad Universitaria, D.F. Mexico (Mexico); Ramos-Bernal, S. [Instituto de Ciencias Nucleares, UNAM, A.P. 70-543 C.P.4510, Ciudad Universitaria, D.F. Mexico (Mexico); Ramos, A. [Instituto de Ciencias Nucleares, UNAM, A.P. 70-543 C.P.4510, Ciudad Universitaria, D.F. Mexico (Mexico); Mosqueira, G.F. [Direccion General de Divulgacion de la Ciencia de la UNAM, A.P. 70-487, C:P, D.F. Mexico 04510 (Mexico); Negron-Mendoza, A. [Instituto de Ciencias Nucleares, UNAM, A.P. 70-543 C.P.4510, Ciudad Universitaria, D.F. Mexico (Mexico)]. E-mail: negron@nuclecu.unam.mx

    2005-12-01

    The aim of this work is to study the irradiation of iron salts in solid state (heptahydrated ferrous sulfate) and in frozen acid solutions. The study is focused on finding their possible use as dosimeters for low temperature irradiations and high doses. The analysis of the samples was made by UV-visible and Moessbauer spectroscopies. The output signal was linear from 0 to 10 MGy for the solid samples, and 0-600 Gy for the frozen solutions. The obtained data is reproducible and easy to handle. For these reasons, heptahydrate iron sulfate is a suitable dosimeter for low temperature and high irradiation doses, in solid state, and in frozen solution.

  5. Fluoride exposure of East African consumers using alkaline salt deposits known as magadi (trona) as a food preparation aid

    DEFF Research Database (Denmark)

    Nielsen, Joan Maj; Dahi, E.

    2002-01-01

    The fluoride content of Tanzanian and Kenyan magadi has been estimated to be in the range 0.1-17.9 mg F- g(-1), which is comparable with that reported elsewhere, but indicating a considerable variation in levels. The median fluoride content of crystalline magadi harvested from the alkaline lakes...... was 2.1 mg g(-1), which was higher than the median of 1.4 mg g(-1) for scooped magadi harvested from the surface soil. The highest median fluoride contents of 3.2 and 2.9 mg g(-1) were found in magadi originating from Lake Magadi, Kenya, and Lake Natron, Tanzania, respectively. It was found...

  6. Effects of ion exchange on stream solute fluxes in a basin receiving highway deicing salts

    Science.gov (United States)

    Shanley, J.B.

    1994-01-01

    At Fever Brook, a 1260-ha forested basin in central Massachusetts, highway deicing salt application increased the solute flux in streamflow by 120% above background flux (equivalent basis) during a 2-yr period. Attempts to isolate the nonsalt component of stream solute fluxes have commonly subtracted salt contributions based on the net Cl flux (Cl output in streamflow minus Cl input in precipitation). In these studies, any net Na flux in excess of the amount needed to balance the net Cl flux has been attributed to weathering. At Fever Brook, however, the net output of Na was less than the net output of Cl, suggesting a loss of Na within the basin. The Na sink was inferred to be cation exchange of Na for Ca and Mg in the soil. A method was developed to quantify the exchange based on a Na budget, which included an independent estimate of the Na flux from weathering. The amount of exchange was apportioned to Ca and Mg based on their relative concentrations in the stream. The background fluxes of Ca and Mg (i.e., those that would occur in the absence of deicing salts) were calculated by subtracting the amounts from ion exchange plus the much smaller direct contributions in deicing salts from the observed fluxes. Ion exchange and direct salt contributions increased the net output fluxes of Ca and Mg, each by 44% above background. In basins that receive deicing salts, failure to account for cation exchange thus may result in an underestimate of the flux of Na from weathering and overestimates of the fluxes of Ca and Mg from weathering.

  7. Polyelectrolyte properties of biopolymers: conductivity and secondary structure of polyriboadenylic acid and its salts in solutions.

    Science.gov (United States)

    Kuznetsov, I A; Vorontsova, O V; Kozlov, A G

    1991-01-01

    Polyriboadenylates of alkali metals were obtained from (1) K(+)-poly(A) (salts 1) and (2) H(+)-poly(A) (salts II) by the ion-exchange method. The conductivity of these salts as well as of H(+)-poly(A) were studied. Salts I and II of the same counterion were shown to have significantly different conductivity coefficients (f) and polyion conductances (lambda 0p). the charge density parameter (xi) was 1.3 and 2.5, respectively, with lambda 0p equal to 44 and 83 ohm-1 cm2 mole-1 for poly(A)-I and poly(A)-II salts, respectively. This is credited to the difference in the conformations of corresponding polyions. The linear dependence of equivalent conductivity on the square root of polymer concentration (Kohlrausch coordinates), earlier obtained for DNA, is also satisfied for the studied polynucleotides. A comparison of the slopes of straight lines in Kohlrausch coordinates for poly(A), simple electrolytes, and for earlier studied polyribouridylic acid salts lends credence to the concepts, developed by a number of authors, that DNA can act as a "buffer" against the ion-ion interaction in concentrated electrolyte solutions. Using the approximation that the polyion conductance is independent of the counterion nature, parameter f (agreeing in this case with Eisenberg parameter phi) has been shown to decrease as the polynucleotide concentration is increased; the decrease is caused by the relaxation effect. The transference numbers of counterions, which have negative values in poly (A)-II solutions, grow with the increase in polymer concentration; the higher the xi, the more apparent is this increase. This is explained by the increase in the fraction of conductivity along the polyion chains ("surface" conductivity) with the growth of polyelectrolyte concentration.

  8. 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.

  9. Electrochemical studies of Zn underpotential/overpotential deposition on a nickel electrode from non-cyanide alkaline solution containing glycine

    Energy Technology Data Exchange (ETDEWEB)

    Ballesteros, J.C. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica (CIDETEQ), Parque Tecnologico Sanfandila, Pedro Escobedo, Queretaro, C.P. 76703 Queretaro (Mexico); Laboratoire d' Electrochimie et de Physicochimie des Materiaux et des Interfaces, LEPMI, UMR 5631 CNRS-INPG-UJF, BP 75, 38402 Saint-Martin d' Heres Cedex (France); Chainet, E.; Ozil, P. [Laboratoire d' Electrochimie et de Physicochimie des Materiaux et des Interfaces, LEPMI, UMR 5631 CNRS-INPG-UJF, BP 75, 38402 Saint-Martin d' Heres Cedex (France); Trejo, G., E-mail: gtrejo@cideteq.mx [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica (CIDETEQ), Parque Tecnologico Sanfandila, Pedro Escobedo, Queretaro, C.P. 76703 Queretaro (Mexico); Meas, Y., E-mail: yunnymeas@cideteq.mx [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica (CIDETEQ), Parque Tecnologico Sanfandila, Pedro Escobedo, Queretaro, C.P. 76703 Queretaro (Mexico)

    2011-06-30

    Highlights: > Zinc electrodeposition from non-cyanide alkaline solution containing glycine was analyzed. > We examine the underpotential (UPD) zinc process on nickel. > 2D instantaneous nucleation and growth mechanism was found for zinc electrodeposition. - Abstract: In this work we present an electrochemical study of the underpotential deposition (UPD) and overpotential deposition (OPD) of zinc onto nickel electrode (NE) from a non-cyanide alkaline solution containing glycine. The studied parameters were zinc concentration, glycine concentration and scanning rate. The analysis of the experimental data clearly showed the presence of UPD and OPD processes that started at -0.8 V vs. SCE and -1.4 V vs. SCE, respectively. The voltammetric studies also indicate diffusion control of the zinc UPD and OPD processes onto the NE. From the potentiostatic transients we found instantaneous nucleation (2D) mechanisms, which agree to that observed in the AFM study. In order to compare the effect of zinc/glycine concentration, we calculate thermodynamic parameters for the OPD process.

  10. Molecular thermodynamics for swelling of a mesoscopic ionomer gel in 1 : 1 salt solutions.

    Science.gov (United States)

    Victorov, A; Radke, C; Prausnitz, J

    2006-01-14

    For a microphase-separated diblock copolymer ionic gel swollen in salt solution, a molecular-thermodynamic model is based on the self-consistent field theory in the limit of strongly segregated copolymer subchains. The geometry of microdomains is described using the Milner generic wedge construction neglecting the packing frustration. A geometry-dependent generalized analytical solution for the linearized Poisson-Boltzmann equation is obtained. This generalized solution not only reduces to those known previously for planar, cylindrical and spherical geometries, but is also applicable to saddle-like structures. Thermodynamic functions are expressed analytically for gels of lamellar, bicontinuous, cylindrical and spherical morphologies. Molecules are characterized by chain composition, length, rigidity, degree of ionization, and by effective polymer-polymer and polymer-solvent interaction parameters. The model predicts equilibrium solvent uptakes and the equilibrium microdomain spacing for gels swollen in salt solutions. Results are given for details of the gel structure: distribution of mobile ions and polymer segments, and the electric potential across microdomains. Apart from effects obtained by coupling the classical Flory-Rehner theory with Donnan equilibria, viz. increased swelling with polyelectrolyte charge and shrinking of gel upon addition of salt, the model predicts the effects of microphase morphology on swelling.

  11. Synthesis and infrared spectra of alkaline earth metal carbonates formed by the reaction of metal salts with urea at high temperature

    Indian Academy of Sciences (India)

    S M Teleb; D El-Sayed Nassr; E M Nour

    2004-12-01

    The metal carbonate, MCO3 (M = Ca, Sr and Ba), was synthesized by a novel method of reacting aqueous solution of each of Ca2+, Sr2+ and Ba2+ salts with urea at high temperature, ∼ 80°C. The reaction products were characterized through elemental analysis and infrared spectra. The infrared spectra of the products are the same as those of the corresponding commercially obtained carbonates. A general reaction describing the formation of MCO3 is proposed.

  12. Titanium Nitride Nanoparticle Electrocatalysts for Oxygen Reduction Reaction in Alkaline Solution

    KAUST Repository

    Ohnishi, R.

    2013-03-12

    Monodispersed TiN nanoparticles with a narrow size distribution (7–23 nm) were synthesized using mesoporous graphitic (mpg)-C3N4 templates with different pore sizes. The nano-materials were examined as electrocatalysts for oxygen reduction reaction (ORR) in alkaline media. The TiN nanoparticles were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 sorption, transmission electron microscopy (TEM), and C-H-N elemental analysis. The ORR current increased as the TiN particle size decreased, and hence the surface area of TiN nanoparticles reactive to ORR increased. Rotating ring disk electrode (RRDE) measurements revealed that the ORR on TiN surfaces proceeded mainly via a two-electron pathway, producing H2O2 as the main product. Mechanistic aspects of ORR on TiN surfaces are discussed.

  13. External application of hypertonic salt solution for treatment of posttraumatic oedema.

    Science.gov (United States)

    Atalar, Hakan; Yavuz, Osman Y; Uras, Ismail; Selek, Hakan; Erakar, Aziz; Sayli, Ugur

    2005-08-01

    In 20 New Zealand rabbits (two groups of 10 rabbits each), hind limb circumference and anterior compartment pressure were measured following ketamin anaesthesia (time zero). During the same anaesthesia, closed transverse proximal tibial shaft fractures were created in both groups. Twenty-four hours after the fractures, during a second anaesthesia, limb circumference and compartment pressure were measured as before, and fractured limbs were fixed to the rabbits' bodies. At the same time, treatment was started: one group received external application of saturated salt solution and the other group received intermittent ice application. During 48 hours of treatment (from 24 to 72 hours) in the saturated salt solution group, the mean limb circumference decreased from 125.70 +/- 9.93 mm to 115.70 +/- 8.78 mm (p = 0.005) and the mean compartment pressure decreased from 18.30 +/- 1.70 mmHg to 12.40 +/- 1.77 mmHg (p = 0.005). In the control group, the mean limb circumference decreased from 127.85 +/- 7.47 mm to 122.00 +/- 6.83 mm (not significant) and the mean compartment pressure decreased from 19.57 +/- 1.27 mmHg to 17.85 +/- 2.67 mmHg (not significant). In short, differences in compartment pressure and limb circumference before and after treatment were statistically significant in the saturated salt solution group (p = 0.005) but not in the control group.

  14. Inefficacy of osmotic backwash induced by sodium chloride salt solution in controlling SWRO membrane fouling

    Science.gov (United States)

    Farooque, A. Mohammed; Al-Jeshi, Subhi; Saeed, Mohamed O.; Alreweli, Ali

    2014-12-01

    A study was conducted to evaluate the efficacy of osmotic backwash induced by high salt (NaCl) concentration solution on feed side of seawater reverse osmosis (SWRO) membranes, online and offline, in controlling membrane fouling and therefore minimizing/eliminating the need for chemical cleaning. SWRO membranes were deliberately fouled by feeding seawater from an open intake located on the Arabian Gulf Coast without dosing chemicals. The fouled membranes were subjected to offline cleaning with the salt solution of up to 25 % concentration. Despite the partial removal of foulants from the membrane surface, SWRO membrane performance could not be restored, indicating the ineffectiveness of osmotic backwash in aiding offline salt cleaning. Similarly, online osmotic backwash was found to be not only ineffective in removing foulants from membrane surfaces but actually increased the fouling rate, as indicated by faster fouling rates compared to other cases. Although the driving force required for the osmotic backwash existed, the generated back flow proved to be insufficient to detach foulants from membrane surfaces. During the study period, the average SWRO membrane flux was maintained between 19 and 23 LMH, whereas the average generated back flow flux by high salt concentration solution was only 11 LMH, which was not adequate to remove foulants from membrane surfaces. Moreover, it seems that the membrane configuration as well as inherent microstructure of SWRO membrane places certain constraints on the osmotic backwash process and renders osmotic backwash ineffective in tackling SWRO membrane fouling. Hence, chemical cleaning is essential to restore SWRO membrane performance whenever fouling occurs, and the use of highly concentrated salt solution does not have any significant benefit. Membrane autopsy revealed only an insignificant accumulation of biofouling layer despite the absence of disinfection. However, it was shown that culturable biofilm bacteria species

  15. Silica precipitation in acidic solutions: mechanism, pH effect, and salt effect.

    Science.gov (United States)

    Gorrepati, Elizabeth A; Wongthahan, Pattanapong; Raha, Sasanka; Fogler, H Scott

    2010-07-06

    This study is the first to show that silica precipitation under very acidic conditions ([HCl] = 2-8 M) proceeds through two distinct steps. First, the monomeric form of silica is quickly depleted from solution as it polymerizes to form primary particles approximately 5 nm in diameter. Second, the primary particles formed then flocculate. A modified Smoluchowski equation that incorporates a geometric population balance accurately describes the exponential growth of silica flocs. Variation of the HCl concentration between 2 and 8 M further showed that polymerization to form primary particles and subsequent particle flocculation become exponentially faster with increasing acid concentration. The effect of salt was also studied by adding 1 M chloride salts to the solutions; it was found that salts accelerated both particle formation and growth rates in the order: AlCl(3) > CaCl(2) > MgCl(2) > NaCl > CsCl > no salt. It was also found that ionic strength, over cation identity, determines silica polymerization and particle flocculation rates. This research reveals that precipitation of silica products from acid dissolution of minerals can be studied apart from the mineral dissolution process. Thus, silica product precipitation from mineral acidization follows a two-step process--formation of 5 nm primary particles followed by particle flocculation--which becomes exponentially faster with increasing HCl concentration and with salts accelerating the process in the above order. This result has implications for any study of acid dissolution of aluminosilicate or silicate material. In particular, the findings are applicable to the process of acidizing oil-containing rock formations, a common practice of the petroleum industry where silica dissolution products encounter a low-pH, salty environment within the oil well.

  16. Rheological properties and thickening mechanism of aqueous diutan gum solution: Effects of temperature and salts.

    Science.gov (United States)

    Xu, Long; Gong, Houjian; Dong, Mingzhe; Li, Yajun

    2015-11-05

    Rheological properties of a new microbial polysaccharide, diutan gum in aqueous solution have been systematically investigated. It is found that molecular aggregates of diutan gum can be formed at a very low concentration (0.12 g/L), and the mechanism of thickening by diutan gum is proposed. The viscosity retention rate of diutan gum changes little when increasing the temperature from 298 K to 348 K or in a high salinity solution (55.5 g L(-1)). Gel structure can be formed in the diutan gum solution, owing to the finding that the dynamic modulus has an exponential relationship with the concentration. The gel properties of diutan gum are not sensitive to temperature, and are virtually independent of cationic environment (Na(+) and Ca(2+)). The temperature/salt tolerance of the diutan gum solution is mainly attributed to its perfect double helix molecular conformation, the location of the side chains of its molecules, and its water retention capacity.

  17. Adding salt to a surfactant solution: Linear rheological response of the resulting morphologies

    Energy Technology Data Exchange (ETDEWEB)

    Gaudino, Danila; Pasquino, Rossana, E-mail: r.pasquino@unina.it; Grizzuti, Nino [DICMaPI, Università degli Studi di Napoli Federico II, P.le Tecchio 80, 80125 Napoli (Italy)

    2015-11-15

    The micellar system composed of Cetylpyridinium Chloride-Sodium Salicylate (CPyCl-NaSal) in brine aqueous solutions has been studied by systematically changing the salt concentration, in order to investigate the rheology of the arising morphologies. In particular, the zero-shear viscosity and the linear viscoelastic response have been measured as a function of the NaSal concentration (with [CPyCl] = 100 mM). The Newtonian viscosity shows a nonmonotonic dependence upon concentration, passing through a maximum at NaSal/CPyCl ≈ 0.6, and eventually dropping at higher salt concentrations. The progressive addition of salt determines first a transition from a Newtonian to a purely Maxwell-like behavior as the length of the micelles significantly increases. Beyond the peak viscosity, the viscoelastic data show two distinct features. On the one hand, the main relaxation time of the system strongly decreases, while the plateau modulus remains essentially constant. Calculations based on the rheological data show that, as the binding salt concentration increases, there is a decrease in micelles breaking rate and a decrease in their average length. On the other hand, in the same concentration region, a low-frequency elastic plateau is measured. Such a plateau is considered as the signature of a tenuous, but persistent branched network, whose existence is confirmed by cryo-transmission electron microscopy images.

  18. Analytical Results from Salt Solution Feed Tank (SSFT) Samples HTF-16-6 and HTF-16-40

    Energy Technology Data Exchange (ETDEWEB)

    Peters, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-09-23

    Two samples from the Salt Solution Feed Tank (SSFT) were analyzed by SRNL, HTF-16-6 and HTF-16-40. Multiple analyses of these samples indicate a general composition almost identical to that of the Salt Batch 8-B feed and the Tank 21H sample results.

  19. Dependence of the solubility of atmospheric oxygen in weakly alkaline aqueous solutions on surfactant concentration

    Science.gov (United States)

    Chistyakova, G. V.; Koksharov, S. A.; Vladimirova, T. V.

    2012-11-01

    The solubility of atmospheric oxygen in solutions of surfactants of different natures at 293 K and pH 8 is determined by gas chromatography. It is found that additives of nonionic surfactants decrease the oxygen content in the solution in the premicellar region and increase its solubility in the micellar region. It is shown that, for anionic surfactants, a decrease in the solubility of O2 is observed over the entire concentration range.

  20. On the kinetics of the hydrogen evolution reaction on Ni-MoOx composite catalysts in alkaline solutions

    Directory of Open Access Journals (Sweden)

    Jović Borka M.

    2012-01-01

    Full Text Available MoO3 particles were co-deposited with Ni onto smooth or rough Ni supports from modified Watt’s baths of different compositions. Morphology and composition of the electrodeposits were characterized by means of cyclic voltammetry, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. The electrocatalytic activity of the composite catalysts for H2 evolution in alkaline solutions was determined by quasi-stationary polarization curves. Activity increases with MoOx content in the Ni deposit up to a limiting value. Composite Ni-MoOx catalyst performed high catalytic activity, similar to that of commercial Ni-RuO2 catalyst. Stability tests showed that Ni-MoOx codeposits are stable under condition of constant current and exhibit excellent tolerance to repeated short-circuiting.

  1. Study on Gold(Ⅰ) Solvent Extraction from Alkaline Cyanide Solution by TBP with Addition of Surfactant

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The new solvent extraction system for gold(Ⅰ) from alkaline cyanide solution by TBP with addition of surfactant in aqueous phase was studied. The effect of various factors, such as equilibrium pH, constitution of organic phase, molar ratio of CPB∶Au(CN)2-, extraction time, aqueous/organic phase ratio, different initial gold concentration, equilibrium temperature, different diluent, different types of extractants and surfactants etc., was inspected. The results show that gold(Ⅰ) can be extracted quantitatively by controlling the quantity of surfactant (CPB); both the equilibrium pH and diluent hardly influence percent extraction. Gold(Ⅰ) percent extraction reaches more than 98% under the optimal experimental conditions. 30% vol TBP diluted by sulphonating kerosene can load gold(Ⅰ) to rather high levels. Loading capacity is in excess of 38 g/L. The extraction mechanism is discussed and the overall extraction reaction is deduced.

  2. Separating nano graphene oxide from the residual strong-acid filtrate of the modified Hummers method with alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xuebing, E-mail: xuebinghu2010@gmail.com [Key Laboratory of Inorganic Membrane, Jingdezhen Ceramic Institute, Jingdezhen 333001 (China); Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 201800 (China); Yu, Yun, E-mail: yunyush@mail.sic.ac.cn [Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 201800 (China); Wang, Yongqing; Zhou, Jianer [Key Laboratory of Inorganic Membrane, Jingdezhen Ceramic Institute, Jingdezhen 333001 (China); Song, Lixin [Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 201800 (China)

    2015-02-28

    Graphical abstract: By adding an alkaline (NaOH or KOH) solution, the unprecipitated nano graphene oxide undergoes fast aggregation from the residual strong-acid filtrate of the modified Hummers method and forms the stable floccules when the pH value of the filtrate is about 1.7. The acid–base interaction with the surface functional groups of the carbon layers plays a role in the aggregation of the unprecipitated nano graphene oxide. - Highlights: • The novel and high-efficient method for separating graphene oxide was showed. • Graphene oxide undergoes aggregation and forms the floccules when pH value is ∼1.7. • The acid–base interaction plays a role in the aggregation of graphene oxide. - Abstract: In the modified Hummers method for preparing graphene oxide, the yellow slurry can be obtained. After filtering through a quantitative filter paper, the strong-acid filtrate containing the unprecipitated nano graphene oxide was gained. The corresponding filtrate was added gradually with an alkaline (NaOH or KOH) solution at room temperature. The unprecipitated nano graphene oxide could undergo fast aggregation when the pH value of the filtrate was about 1.7 and formed the stable floccules. X-ray diffraction analysis shows the dominant peak of the floccules is about 11°, which accords to the peak of graphene oxide. Spectra of X-ray photoelectron spectroscopy confirm the presence in the floccules of an abundance of oxygen functional groups and the purified graphene oxide floccules can be obtained. Atomic force microscopy measurement shows the graphene oxide floccules consists of sheet-like objects, mostly containing only a few layers (about 5 layers). Zeta potential analysis demonstrates the surface charge of the graphene oxide is pH-sensitive and its isoelectric point is ∼1.7. The flocculation mechanism of graphene oxide ascribes to the acid–base interaction with the surface functional groups of the carbon layers.

  3. Molecular Thermodynamics for Swelling of a Mesoscopic Ionomer Gelin 1:1 Salt Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Victorov, Alexey; Radke, Clayton; Prausnitz,John

    2005-06-15

    For a microphase-separated diblock copolymer ionic gel swollen in salt solution, a molecular-thermodynamic model is based on the self-consistent field theory in the limit of strongly segregated copolymer subchains. The geometry of microdomains is described using the Milner generic wedge construction neglecting the packing frustration. Thermodynamic functions are expressed analytically for gels of lamellar, bicontinuous, cylindrical and spherical morphologies. Molecules are characterized by chain composition, length, rigidity, degree of ionization, and by effective polymer-polymer and polymer-solvent interaction parameters. The model predicts equilibrium solvent uptakes and the equilibrium microdomain spacing for gels swollen in salt solutions. Results are given for details of the gel structure: distribution of mobile ions and polymer segments, and the electric potential across microdomains. Apart from effects obtained by coupling classical Flory-Rehner theory with Donnan equilibria, viz., increased swelling with polyelectrolyte charge and shrinking of gel upon addition of salt, the model predicts the effects of microphase morphology on swelling.

  4. Viscosity-Reducing Bulky-Salt Excipients Prevent Gelation of Protein, but Not Carbohydrate, Solutions.

    Science.gov (United States)

    Kumar, Awanish; Klibanov, Alexander M

    2017-01-23

    The problem of gelation of concentrated protein solutions, which poses challenges for both downstream protein processing and liquid formulations of pharmaceutical proteins, is addressed herein by employing previously discovered viscosity-lowering bulky salts. Procainamide-HCl and the salt of camphor-10-sulfonic acid with L-arginine (CSA-Arg) greatly retard gelation upon heating and subsequent cooling of the model proteins gelatin and casein in water: Whereas in the absence of additives the proteins form aqueous gels within several hours at room temperature, procainamide-HCl for both proteins and also CSA-Arg for casein prevent gel formation for months under the same conditions. The inhibition of gelation by CSA-Arg stems exclusively from the CSA moiety: CSA-Na was as effective as CSA-Arg, while Arg-HCl was marginally or not effective. The tested bulky salts did not inhibit (and indeed accelerated) temperature-induced gel formation in aqueous solutions of all examined carbohydrates-starch, agarose, alginate, gellan gum, and carrageenan.

  5. Study on Properties of Microemulsion AEO-9/Butanol/Cyclohexane/Salt Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    Qiu Guanming; Chen Yongjie; Tian Yiguang; Fang Li; Xiao Linjiu; Sun Yanbin

    2004-01-01

    The microemulsion AEO-9/butanol/cyclohexane/nitrate aqueous solution (or ammonium salt aqueous solution) was studied, which was used as 'micro-reactor' in preparing long afterglow phosphor materials SrAl2O4: Eu2+ ,Dy3+. The phase behavior of microemulsion was investigated. The radius of inner water droplet Rw and the change of standard free energy ΔG*o→i were obtained by means of dilution method and theoretical calculation. The result shows that with the increase of W/S, the area of microemulsion region decreases, Rw and ΔG*o→i increase and the microemulsion stability decreases. The structure change and formation area of microemulsion AEO-9/butanol/cyclohexane/nitrate aqueous solution ( or ammonium salt aqueous solution) were offered for the adoption of a synthesis method with newly high efficiency and utility. The particular size and its distribution theory gist, fluorescence life-span, and quenching concentration parameter data were expected. A new approach was explored for finding a new preparation method of rare earths afterglow materials and increasing luminescence intensity without crashing.

  6. Mechanism of conversion of cellulosic wastes to liquid fuels in alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Molton, P.M.; Demmitt, T.F.; Donovan, J.M.; Miller, R.K.

    1978-01-01

    Conversion of cellulosic wastes into liquid oils is being practiced on a pilot plant scale at Albany, OR, but the fundamental chemistry of the process is poorly understood. We report our findings on the aqueous alkaline digestion of pure cellulose, on a laboratory scale, in a closely related system. Our intent is to elucidate the reaction mechanisms involved in oil and tar formation, and to identify products of potential value. A 30 wt % aqueous slurry of pure cellulose in up to 1.2 N alkali (sodium hydroxide or carbonate), heated to 350/sup 0/C over a 3.5 hour period showed a sharp discontinuity in heating rate at 265 to 270/sup 0/C, indicating the onset of a discrete liquefaction reaction not hitherto observed. A series of 129 autoclave experiments analyzed by statistical methods indicated that carbon monoxide, while it promotes the attainment of high yields as claimed by the Bureau of Mines, is not necessary for the reaction to proceed. Analysis of the products by /sup 13/C-NMR, GC/MS, and gel permeation chromatography indicated that the nonvolatile fraction of the oil consists of 44% aromatic carbon and 7% aromatic hydrogen, corresponding to a benzenoid polyaromatic with a substitution ratio of 5:1. However, oxygen content of the nonvolatile fraction and distillable oil is approximately the same. Since the oil contains a series of polyalkylated furans, this suggests that the char is a poly-furan rather than a conventional asphaltene derivative. Volatile products from the oil fraction consist of furans, cyclic ketones, linear and branched alkenes, and phenolics. The high proportion of phenolics relative to normal crude oil could explain the observed highly corrosive nature of the biomass-derived oils.

  7. Phase behavior of concentrated hydroxypropyl methylcellulose solution in the presence of mono and divalent salt.

    Science.gov (United States)

    Almeida, Nalinda; Rakesh, Leela; Zhao, Jin

    2014-01-01

    Thermo reversible sol-gel transitions of hydroxypropylmethylcellulose (HPMC) are critical for many pharmaceutical, cosmetic, and food applications. This study examined the effects of salt (NaCl and CaCl₂) on the viscoelastic properties of concentrated low molecular weight HPMC solutions and found that the gelation temperature decreased linearly as a function of salt concentrations, independent of valency of cations and the mole concentration of anions. Thermal analysis showed that the depression of melting temperature can be fitted for both NaCl and CaCl₂ as a function of the total number of ions by a single linear curve, which was consistent with the melting point depression of pure water by NaCl and CaCl₂, but with a higher linear slope.

  8. A Chronoamperometric Screen Printed Carbon Biosensor Based on Alkaline Phosphatase Inhibition for W(VI Determination in Water, Using 2-Phospho-l-Ascorbic Acid Trisodium Salt as a Substrate

    Directory of Open Access Journals (Sweden)

    Ana Lorena Alvarado-Gámez

    2015-01-01

    Full Text Available This paper presents a chronoamperometric method to determine tungsten in water using screen-printed carbon electrodes modified with gold nanoparticles and cross linked alkaline phosphatase immobilized in the working electrode. Enzymatic activity over 2-phospho-l-ascorbic acid trisodium salt, used as substrate, was affected by tungsten ions, which resulted in a decrease of chronoamperometric current, when a potential of 200 mV was applied on 10 mM of substrate in a Tris HCl buffer pH 8.00 and 0.36 M of KCl. Calibration curves for the electrochemical method validation, give a reproducibility of 5.2% (n = 3, a repeatability of 9.4% (n = 3 and a detection limit of 0.29 ± 0.01 µM. Enriched tap water, purified laboratory water and bottled drinking water, with a certified tungsten reference solution traceable to NIST, gave a recovery of 97.1%, 99.1% and 99.1% respectively (n = 4 in each case and a dynamic range from 0.6 to 30 µM. This study was performed by means of a Lineweaver–Burk plot, showing a mixed kinetic inhibition.

  9. A chronoamperometric screen printed carbon biosensor based on alkaline phosphatase inhibition for W(IV) determination in water, using 2-phospho-L-ascorbic acid trisodium salt as a substrate.

    Science.gov (United States)

    Alvarado-Gámez, Ana Lorena; Alonso-Lomillo, María Asunción; Domínguez-Renedo, Olga; Arcos-Martínez, María Julia

    2015-01-22

    This paper presents a chronoamperometric method to determine tungsten in water using screen-printed carbon electrodes modified with gold nanoparticles and cross linked alkaline phosphatase immobilized in the working electrode. Enzymatic activity over 2-phospho-l-ascorbic acid trisodium salt, used as substrate, was affected by tungsten ions, which resulted in a decrease of chronoamperometric current, when a potential of 200 mV was applied on 10 mM of substrate in a Tris HCl buffer pH 8.00 and 0.36 M of KCl. Calibration curves for the electrochemical method validation, give a reproducibility of 5.2% (n = 3), a repeatability of 9.4% (n = 3) and a detection limit of 0.29 ± 0.01 µM. Enriched tap water, purified laboratory water and bottled drinking water, with a certified tungsten reference solution traceable to NIST, gave a recovery of 97.1%, 99.1% and 99.1% respectively (n = 4 in each case) and a dynamic range from 0.6 to 30 µM. This study was performed by means of a Lineweaver-Burk plot, showing a mixed kinetic inhibition.

  10. A Chronoamperometric Screen Printed Carbon Biosensor Based on Alkaline Phosphatase Inhibition for W(VI) Determination in Water, Using 2-Phospho-l-Ascorbic Acid Trisodium Salt as a Substrate

    Science.gov (United States)

    Alvarado-Gámez, Ana Lorena; Alonso-Lomillo, María Asunción; Domínguez-Renedo, Olga; Arcos-Martínez, María Julia

    2015-01-01

    This paper presents a chronoamperometric method to determine tungsten in water using screen-printed carbon electrodes modified with gold nanoparticles and cross linked alkaline phosphatase immobilized in the working electrode. Enzymatic activity over 2-phospho-l-ascorbic acid trisodium salt, used as substrate, was affected by tungsten ions, which resulted in a decrease of chronoamperometric current, when a potential of 200 mV was applied on 10 mM of substrate in a Tris HCl buffer pH 8.00 and 0.36 M of KCl. Calibration curves for the electrochemical method validation, give a reproducibility of 5.2% (n = 3), a repeatability of 9.4% (n = 3) and a detection limit of 0.29 ± 0.01 μM. Enriched tap water, purified laboratory water and bottled drinking water, with a certified tungsten reference solution traceable to NIST, gave a recovery of 97.1%, 99.1% and 99.1% respectively (n = 4 in each case) and a dynamic range from 0.6 to 30 μM. This study was performed by means of a Lineweaver–Burk plot, showing a mixed kinetic inhibition. PMID:25621602

  11. Light emission of singlet oxygen electrogenerated in alkaline aqueous solutions%碱性水溶液中的单线态氧电致化学发光

    Institute of Scientific and Technical Information of China (English)

    王伟; 郭吉兆; 崔华

    2008-01-01

    Light emission was observed in a simple aqueous solution containing an alkaline salt such as K2HPO4, Na2CO3 or Na2B4O7 when a double-step potential was applied to the electrode. The light emitter was identified to be singlet oxygen by both spectral features and its responses to singlet oxygen quenchers and enhancers. The Haber-Weiss reaction of hydrogen peroxide electrogenerated from dissolved oxygen with superoxide anion formed by the electro-oxidation of hydrogen peroxide was validated to be responsible for this light emission.%研究发现:当在碱性无机盐(如K2HPO4,Na2CO3或Na2 B4O7)水溶液中施加适当调制的双脉冲电信号时,可以在电极表面观察到发光.通过研究发光光谱以及各种单线态氧抑制/增强荆对化学发光强度的影响规律,确定该体系的发光体为单线态氧.其发光机理为负电位下溶解氧被电还原为过氧化氢,在随后的正脉冲下产生超氧基阴离子,两者以Haber-Weiss反应机理生成单线态氧并产生光发射.

  12. Investigation of the passive behaviour of AZ31B alloy in alkaline solutions

    OpenAIRE

    A. Fattah-alhosseini; M. Sabaghi Joni

    2014-01-01

    In this work, the passivity of AZ31B alloy in NaOH solutions was studied by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and Mott–Schottky analysis. Potentiodynamic polarization results indicated that decreasing NaOH concentration leads to decrease the corrosion rate of this alloy. EIS results showed that the reciprocal capacitance (1/C) of the passive film is directly proportional to its thickness which increases with decreasing NaOH concentration. Therefore, it...

  13. Preparation and Characterization of Organic-Inorganic Hybrid Hydrogel Electrolyte Using Alkaline Solution

    Directory of Open Access Journals (Sweden)

    Masanobu Chiku

    2011-09-01

    Full Text Available Organic-inorganic hybrid hydrogel electrolytes were prepared by mixing hydrotalcite, cross-linked potassium poly(acrylate and 6 M KOH solution. The organic-inorganic hybrid hydrogel electrolytes had high ionic conductivity (0.456–0.540 S cm−1 at 30 °C. Moreover, the mechanical strength of the hydrogel electrolytes was high enough to form a 2–3 mm thick freestanding membrane because of the reinforcement with hydrotalcite.

  14. Enzymatic methods for the determination of pollution in seawater using salt resistant alkaline phosphatase from eggs of the sea urchin Strongylocentrotus intermedius.

    Science.gov (United States)

    Menzorova, Natalie I; Seitkalieva, Alexandra V; Rasskazov, Valerу A

    2014-02-15

    A new salt resistant alkaline phosphatase from eggs of the sea urchin Strongylocentrotus intermedius (StAP) has been shown to have a unique property to hydrolyze substrate in seawater without loss of enzymatic activity. The enzyme has pH optimum at 8.0-8.5. Model experiments showed various concentrations of copper, zinc, cadmium and lead added to seawater or a standard buffer mixture to inhibit completely the enzyme activity at the concentrations of 15-150 μg/l. StAP sensitivity to the presence in seawater of metals, pesticides, detergents and oil products appears to be considerably less. Samples of seawater taken from aquatic areas of the Troitsy Bay of the Peter the Great Bay, Japan Sea have been shown to inhibit the enzyme activity; the same was shown for the samples of fresh waters. The phosphatase inhibition assay developed proved to be highly sensitive, technically easy-to use allowing to test a great number of samples.

  15. Equilibrium, kinetic and thermodynamic study of cesium adsorption onto nanocrystalline mordenite from high-salt solution.

    Science.gov (United States)

    Lee, Keun-Young; Park, Minsung; Kim, Jimin; Oh, Maengkyo; Lee, Eil-Hee; Kim, Kwang-Wook; Chung, Dong-Yong; Moon, Jei-Kwon

    2016-05-01

    In this study, the equilibrium, kinetics and thermodynamics of cesium adsorption by nanocrystalline mordenite were investigated under cesium contamination with high-salt solution, simulating the case of an operation and decommissioning of nuclear facilities or an accident during the processes. The adsorption rate constants were determined using a pseudo second-order kinetic model. The kinetic results strongly demonstrated that the cesium adsorption rate of nano mordenite is extremely fast, even in a high-salt solution, and much faster than that of micro mordenite. In the equilibrium study, the Langmuir isotherm model fit the cesium adsorption data of nano mordenite better than the Freundlich model, which suggests that cesium adsorption onto nano mordenite is a monolayer homogeneous adsorption process. The obtained thermodynamic parameters indicated that the adsorption involved a very stable chemical reaction. In particular, the combination of rapid particle dispersion and rapid cesium adsorption of the nano mordenite in the solution resulted in a rapid and effective process for cesium removal without stirring, which may offer great advantages for low energy consumption and simple operation.

  16. Hydraulic conductivity in response to exchangeable sodium percentage and solution salt concentration

    Directory of Open Access Journals (Sweden)

    Jefferson Luiz de Aguiar Paes

    2014-10-01

    Full Text Available Hydraulic conductivity is determined in laboratory assays to estimate the flow of water in saturated soils. However, the results of this analysis, when using distilled or deionized water, may not correspond to field conditions in soils with high concentrations of soluble salts. This study therefore set out to determine the hydraulic conductivity in laboratory conditions using solutions of different electrical conductivities in six soils representative of the State of Pernambuco, with the exchangeable sodium percentage adjusted in the range of 5-30%. The results showed an increase in hydraulic conductivity with both decreasing exchangeable sodium percentage and increasing electrical conductivity in the solution. The response to the treatments was more pronounced in soils with higher proportion of more active clays. Determination of hydraulic conductivity in laboratory is routinely performed with deionized or distilled water. However, in salt affected soils, these determinations should be carried out using solutions of electrical conductivity different from 0 dS m-1, with values close to those determined in the saturation extracts.

  17. Spectroscopic study of Mg(II) ion influence on the autoxidation of gallic acid in weakly alkaline aqueous solutions

    Science.gov (United States)

    Nikolić, G. M.; Veselinović, A. M.; Nikolić, R. S.; Mitić, S. S.

    2011-12-01

    Gallic acid autoxidation in weakly alkaline aqueous solutions was studied by UV-Vis spectrophotometry and ESR spectroscopy under various conditions. Lowering the pH value from 10 to 8.5 probably changes the mechanism of the autoxidation reaction as evidenced by the different time variations of UV-Vis spectra of solutions. The presence of Mg(II) ions greatly influences the autoxidation reaction at pH 8.5. Although the UV-Vis spectral changes with time follow the similar pattern during the gallic acid autoxidation at pH 10 and at pH 8.5 in the presence of Mg(II) ions, some small differences indicate that Mg(II) ions not only affect the electron density of absorbing species but also influence the overall mechanism of the autoxidation reaction. ESR spectra of free radials formed during the initial stage of gallic acid autoxidation at pH 8.5 in the presence of Mg(II) ions were recorded. Computer simulation of ESR spectra allows partial characterization of these free radicals.

  18. Experimental and theoretical investigation on corrosion inhibition of AA5052 aluminium alloy by L-cysteine in alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dapeng; Gao, Lixin [School of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Zhang, Daquan, E-mail: zhangdaquan@shiep.edu.cn [School of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Yang, Dong [School of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Wang, Hongxia; Lin, Tong [Institute for Frontier Materials, Deakin University, Geelong, VIC 3216 (Australia)

    2016-02-01

    The corrosion inhibition of L-cysteine on AA5052 aluminium alloy in 4 mol/L NaOH solution was investigated by hydrogen gas evolution experiment, polarisation curve, galvanostatic discharge, electrochemical impedance spectroscopy measurements and quantum chemical calculations. The adsorption of L-cysteine on aluminium alloy surface obeyed the amended Langmuir's adsorption isotherm. The polarisation curves indicated that L-cysteine acted as a cathodic inhibitor to inhibit cathodic reaction. The inhibition mechanism was dominated by the geometric covering effect. The galvanostatic discharge shows that the additives restrain the hydrogen evolution and increase the anodic utilization rate. Quantum chemical calculations indicated that L-cysteine molecules mainly interacted with on the carboxyl groups on the aluminium alloy surface. A strong hybridization occurred between the s-orbital and p-orbital of reactive sites in the L-cysteine molecule and the sp-orbital of Aluminium. - Highlights: • L-cysteine was used as corrosion inhibitor for Al alloy in alkaline solution. • Adsorption of L-cysteine on Al alloy surface obeyed the amended Langmuir's isotherm. • L-cysteine molecules interacted with the carboxyl groups on the Al alloy surface. • A strong orbital hybridization occurred between the reactive sites in L-cysteine and Al.

  19. Thermodynamic Model for ThO2(am) Solubility in Alkaline Silica Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Rai, D [Rai Enviro-Chem, LLC, Yachats, OR (United States); Yui, Mikazu [Japan Atomic Energy Agency, Tokai (Japan); Moore, Dean A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lumetta, Gregg J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rosso, Kevin M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xia, Yuanxian [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Felmy, Andrew R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Skomurski, Frances N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2008-10-11

    literature, agreed closely with the extensive experimental data and showed that under alkaline conditions aqueous Si makes very strong complexes with Th.

  20. Investigation of the passive behaviour of AZ31B alloy in alkaline solutions

    Directory of Open Access Journals (Sweden)

    A. Fattah-alhosseini

    2014-06-01

    Full Text Available In this work, the passivity of AZ31B alloy in NaOH solutions was studied by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS and Mott–Schottky analysis. Potentiodynamic polarization results indicated that decreasing NaOH concentration leads to decrease the corrosion rate of this alloy. EIS results showed that the reciprocal capacitance (1/C of the passive film is directly proportional to its thickness which increases with decreasing NaOH concentration. Therefore, it is clear that dilute NaOH solutions offer better conditions for forming the passive films with higher protection behaviour, due to the growth of a much thicker and less defective films. The Mott–Schottky analysis revealed that the passive films displayed n-type semiconductive characteristics, where the oxygen vacancies and interstitials (over the cation vacancies preponderated. Also, Mott–Schottky results showed that the donor densities evaluated from Mott–Schottky plots are in the range of 1020 cm−3 and decreased with decreasing NaOH concentration.

  1. Electrochemical Behavior of Nano-grained Pure Copper in Dilute Alkaline Solution with Chloride Ion Trace

    Science.gov (United States)

    Fattah-Alhosseini, Arash; Imantalab, Omid; Attarzadeh, Farid Reza

    2016-10-01

    Effect of nano-grained structure on the interface behavior of pure copper in 0.01M KOH solution with chloride ion trace is investigated by various electrochemical techniques. Nano-grained structure was achieved by accumulative roll bonding (ARB) technique. Before any electrochemical measurements, microstructure was evaluated by means of optical microscopy and transmission electron microscopy (TEM). TEM observations showed that nano-grains (with an average size of below 100 nm) appeared after eight passes of ARB. Polarization curves revealed that increasing chloride ion concentration leads to a decrease in the corrosion and pitting potentials of both annealed and nano-grained pure copper samples. Electrochemical impedance spectroscopy revealed that chloride ion trace lowers passive film resistance and charge-transfer resistance in both annealed and nano-grained samples. Mott-Schottky analysis showed that the surface films formed on annealed and nano-grained samples in KOH solution with and without NaCl addition are of p-type semiconducting behavior. Moreover, this analysis showed that the acceptor density increases by increasing chloride ion concentration.

  2. Modeling pitting corrosion of iron exposed to alkaline solutions containing nitrate and nitrite

    Science.gov (United States)

    Chen, Lifeng

    2001-07-01

    Pitting corrosion could be extremely serious for dilute high-level radioactive waste stored or processed in carbon steel tanks at the Savannah River Site. In these solutions, nitrate is an aggressive ion with respect to pitting of carbon steel while nitrite can be used as an inhibitor. Excessive additions of nitrite increase the risk of generating unstable nitrogen compounds during waste processing, and insufficient additions of nitrite could increase the risk of corrosion-induced failure. Thus there are strong incentives to obtain a fundamental understanding of the role of nitrite in pitting corrosion prevention with these solution chemistries. In this dissertation, both a 1-D and a 2-D model are used to study the pitting mechanism as a function of nitrite/nitrate ratios. The 1-D model used BAND(J) to test a reaction mechanism for the passivation behavior by comparing the predicted Open Circuit Potential (OCP) with OCP data from experiments at different NO2-/NO3- ratio. The model predictions are compared with Cyclic Potentiodynamic Polarization (CPP) experiments. A 2-D model was developed for the propagation of a pit in iron by writing subroutines for finite element software of GAMBIT and FIDAP. Geometrically distributed anodic and cathodic reactions are assumed. The results show three partial explanations describing the inhibition influence of nitrite to iron corrosion: the competing reduction reaction of nitrate to nitrite, the formation of Fe(OH)+, and the function of the porous film. The current distributions and the effect of porosity of the film on pH are also explained. The calculation results also show that rate of pit growth decreases as the pit diameter increases until it reaches a constant value. The profile of the local current density on the pit wall is parabolic for small pits and it changes to a linear distribution for large pits. The model predicts that addition of nitrite will decrease the production of ferrous ions and those can prevent iron from

  3. Hydrogen evolution at catalytically-modified nickel foam in alkaline solution

    Science.gov (United States)

    Pierozynski, Boguslaw; Mikolajczyk, Tomasz; Kowalski, Ireneusz M.

    2014-12-01

    This work reports on hydrogen evolution reaction (HER) studied at catalytically modified nickel foam material. The HER was examined in 0.1 M NaOH solution on as received, as well as for Pd and Ru-activated nickel foam catalyst materials, produced via spontaneous deposition of trace amounts of these elements. Catalytic modification of nickel foam results in significant facilitation of the HER kinetics, as manifested through considerably reduced, a.c. impedance-derived values of charge-transfer resistance parameter and substantially altered Tafel polarization slopes. The presence of catalytic additives is clearly revealed through hydrogen underpotential deposition (H UPD) phenomenon, as well as spectroscopically from SEM (Scanning Electron Microscopy) analysis.

  4. Red-emitting alkaline-earth rare-earth pentaoxometallates powders prepared by metal carboxylates solution

    Indian Academy of Sciences (India)

    Kyu-Seog Hwang; Sung-Dae Kim; Seung Hwangbo; Jin-Tae Kim

    2013-06-01

    Moisture-insensitive metal carboxylates that are mostly liquids at room temperature have been first applied to the preparation of strontium europium aluminate (Sr2EuAlO5) powders for red-emitting phosphor under near ultraviolet radiation. Strontium naphthenate, aluminium-2-ethylhexanoate and europium-2-ethylhexanoate were dissolved with toluene to prepare starting solution. Precursor pyrolyzed at 500 °C for 240 min was finally annealed at 900–1200 °C for 240 min in Ar. X-ray diffraction analysis, field emission–scanning electron microscope and fluorescent spectrophotometer were used to evaluate structural and optical properties. For the 1000 °C-annealed powders with regular shape and narrow size distribution confirmed by FE–SEM observation, strong red emission at 615nm under the excitation of 395nm maximum was reached, then the higher annealed samples at above 1100 °C gave the lower emission intensities.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-01

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

  6. Determination of Stoichiometry of Solutes in Molten Salt Solvents by Correlations of Relative Raman Band Intensities

    DEFF Research Database (Denmark)

    Boghosian, Soghomon; Berg, Rolf W.

    1999-01-01

    Raman spectroscopy has been used to determine the stoichiometry of solute complexes in molten salts at high temperatures under static equilibrium conditions, A simple formalism is derived for correlating relative Raman band intensities with stoichiometric coefficients. The experimental procedures......); (2) Nb2O5 + nS(2)O(7)(2-) (1) --> Y2n- (1); (3) MoO3 + nS(2)O(7)(2-) (1) --> Z(2n)- (1). It is shown that the solute complex species formed in the studied reactions have, respectively, the following stoichiometries: (1) n = 2, (VO)(2)O(SO4)(4)(4-); (2) n = 3, NbO(SO4)(3)(3-); (3) n = 1, MoO(SO4)(2)(2-)....

  7. Oxygen effect in bacteriophages irradiated in different media. 1. Irradiation in salt solution

    Energy Technology Data Exchange (ETDEWEB)

    Korystov, Yu.N.; Veksler, F.B. (AN SSSR, Pushchino-na-Oke. Inst. Biologicheskoj Fiziki)

    1983-09-14

    The oxygen effect (OE) on bacteriophage T4 in a salt solution was studied. It is shown that the sign and magnitude of OE depend on the conditions of the postirradiation incubation of the phage in irradiated medium. The direct OE is due to postirradiation lesion of the phage by hydrogen peroxide which is formed in greater amounts after irradiation in oxygen than in anoxia. The addition of catalase is shown to eliminate the postirradiation inactivation of the phage. In this case an opposite OE is observed. The mechanism of this effect is a scavenge of hydrogen atoms which damage the phage by oxygen. In the presence of catalase the OE depends also on pH of the solution. It is suggested that the hydroxyl radical arising from the reaction of H/sub 2/O/sub 2/ with Fe/sup 2 +/ is responsible for the damaging effect of H/sub 2/O/sub 2/.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. Evaluation of poly (aspartic acid sodium salt) as a draw solute for forward osmosis.

    Science.gov (United States)

    Gwak, Gimun; Jung, Bokyung; Han, Sungsoo; Hong, Seungkwan

    2015-09-01

    Poly (aspartic acid sodium salt) (PAspNa) was evaluated for its potential as a novel draw solute in forward osmosis (FO). The inherent advantages of PAspNa, such as good water solubility, high osmotic pressure, and nontoxicity, were first examined through a series of physicochemical analyses and atomic-scale molecular dynamics simulations. Then, lab-scale FO tests were performed to evaluate its suitability in practical processes. Compared to other conventional inorganic solutes, PAspNa showed comparable water flux but significantly lower reverse solute flux, demonstrating its suitability as a draw solute. Moreover, fouling experiments using synthetic wastewater as a feed solution demonstrated that PAspNa reversely flowed to the feed side reduced inorganic scaling on the membrane active layer. The recyclability of PAspNa was studied using both nanofiltration (NF) and membrane distillation (MD) processes, and the results exhibited its ease of recovery. This research reported the feasibility and applicability of FO-NF or FO-MD processes using PAspNa for wastewater reclamation and brackish water desalination.

  10. Electroreduction of oxygen on Pt nanoparticle/carbon nanotube nanocomposites in acid and alkaline solutions

    Energy Technology Data Exchange (ETDEWEB)

    Alexeyeva, N. [Institute of Chemistry, University of Tartu, Jakobi 2, 51014 Tartu (Estonia); Tammeveski, K., E-mail: kaido@chem.ut.e [Institute of Chemistry, University of Tartu, Jakobi 2, 51014 Tartu (Estonia); Lopez-Cudero, A.; Solla-Gullon, J.; Feliu, J.M. [Instituto de Electroquimica, Universidad de Alicante, Apartado 99, 03080 Alicante (Spain)

    2010-01-01

    The kinetics of O{sub 2} reduction on novel electrocatalyst materials deposited on carbon substrates were studied in 0.5 M H{sub 2}SO{sub 4} and in 0.1 M NaOH solutions using the rotating disk electrode (RDE) technique. Pt nanoparticles (PtNP) supported on single-walled (PtNP/SWCNT) and multi-walled carbon nanotubes (PtNP/MWCNT) were prepared using two different synthetic routes. Before use, the CNTs were cleaned to minimize the presence of metal impurities coming from the catalyst used in the synthesis of this material, which can interfere in the electrochemical response of the supported Pt nanoparticles. The composite catalyst samples were characterised by transmission electron microscopy (TEM) showing a good dispersion of the particles at the surface of the carbon support and an average Pt particle size of 2.4 +- 0.7 nm in the case of Pt/CNTs prepared in the presence of citrate and of 3.8 +- 1.1 nm for Pt/CNTs prepared in microemulsion. The values of specific activity (SA) and other kinetic parameters were determined from the Tafel plots taking into account the real electroactive area of each electrode. The electrodes exhibited a relatively high electrocatalytic activity for the four-electron oxygen reduction reaction to water.

  11. Development of nano indium tin oxide (ITO) grains by alkaline hydrolysis of In(III) and Sn(IV) salts

    Indian Academy of Sciences (India)

    Nimai Chand Pramanik; Prasanta Kumar Biswas

    2002-11-01

    Indium tin oxide (ITO) nano powders of different compositions (In : Sn = 90 : 10, 70 : 30 and 50 : 50) were prepared by heat treatment (300–450°C) of mixed hydroxides of In(III) and Sn(IV). The hydroxides were obtained by the reaction of aq. NH3 with mixed aq. solutions of In(NO3)3 and SnCl4. FTIR and TG/DTA studies revealed that powders existed as In(OH)3 H2O−SnO3H2 H2O in the solid state and then they transformed to In2O3–SnO2 via some metastable intermediates after 300°C. Cubic phase of In2O3 was identified by XRD for the oxides up to 30% of Sn. Particle size measurements of the solid dispersed in acetone and SEM study for microstructure showed that the oxides were in the nano range (55–75 nm) whereas the size range determined from Debye–Scherrer equation were 11–24 nm.

  12. Determining the Enthalpy of Vaporization of Salt Solutions Using the Cooling Effect of a Bubble Column Evaporator

    Science.gov (United States)

    Fan, Chao; Pashley, Richard M.

    2016-01-01

    The enthalpy of vaporization (?H[subscript vap]) of salt solutions is not easily measured, as a certain quantity of pure water has to be evaporated from a solution, at constant composition, and at a fixed temperature and pressure; then the corresponding heat input has to be measured. However, a simple bubble column evaporator (BCE) was used as a…

  13. [Electric conductivity changes in salt-free solutions in connection with the formation of polyriboadenylic and polyribouridylic acid complexes].

    Science.gov (United States)

    Filippov, S M; Vorontsova, O V; Kuznetsov, I A

    1984-01-01

    Conductometric and spectrophotometric investigations of concentrated salt-free solutions of poly(A) -- poly(U) demonstrated the 1:1 complex formation. It was accomplished by the increase of solution conductivity in contrast to the situation when DNA redenaturation takes place.

  14. On-site production of a dialysis bath from dry salts. Results of solute concentration control by routine clinical chemistry.

    Science.gov (United States)

    Beige, Joachim; Lutter, Steffen; Martus, Peter

    2012-06-01

    BACKGROUND.: Dialysis bath production, at least in Europe, is currently based on pre-produced aqueous solutions of dialysis salts (concentrate), which are re-handled by dialysis machines to deliver the final dialysate concentrations. Because of the logistics of aqueous solution creation, a large amount of transportation capacity is needed. Therefore, we changed this process to use pre-produced dry salt containers and to undertake in-clinic dissolution of salts and concentration production. Because no preclinical control for solute concentrations is available so far using this new process, we employed routine clinical chemistry analytics. METHODS.: We report the controls of solute concentrations created by these methods for 746 samples of concentrates and 151 dissolution processes. For analysis, absolute and relative deviations from prescriptions and associations between the solute concentrations and the density controls of the concentrates were computed. RESULTS.: A total of 98% of all the concentrates were found to be within a 10% margin of error from the prescriptions. The mean relative deviation of the solute concentrations from the prescriptions was -0.635 ± 3.83%. Among particular solutes, sodium had the highest maximum deviation of 26 mmol/L from the prescription. Calcium and magnesium (small concentration solutes) exhibited small systematic errors of 1.37 and 1.22%, respectively. Other solute concentrations showed random errors only and no associations with the mean relative deviations of all the solutes within a production batch or with the density controls. CONCLUSIONS.: Single solute concentration control by routine clinical chemistry after dry salt production of concentrates is a valuable additional tool for monitoring clinical risk with dialysate concentrates. The analytical random error of clinical chemistry exceeds the weight tolerance of production; therefore, such analytics cannot be used for precision production and control of dry salt containers.

  15. Extraction of Zinc and Manganese from Alkaline and Zinc-Carbon Spent Batteries by Citric-Sulphuric Acid Solution

    Directory of Open Access Journals (Sweden)

    Francesco Ferella

    2010-01-01

    Full Text Available The paper is focused on the recovery of zinc and manganese from alkaline and zinc-carbon spent batteries. Metals are extracted by sulphuric acid leaching in the presence of citric acid as reducing agent. Leaching tests are carried out according to a 24 full factorial design, and empirical equations for Mn and Zn extraction yields are determined from experimental data as a function of pulp density, sulphuric acid concentration, temperature, and citric acid concentration. The highest values experimentally observed for extraction yields were 97% of manganese and 100% of zinc, under the following operating conditions: temperature 40∘C, pulp density 20%, sulphuric acid concentration 1.8 M, and citric acid 40 g L-1. A second series of leaching tests is also performed to derive other empirical models to predict zinc and manganese extraction. Precipitation tests, aimed both at investigating precipitation of zinc during leaching and at evaluating recovery options of zinc and manganese, show that a quantitative precipitation of zinc can be reached but a coprecipitation of nearly 30% of manganese also takes place. The achieved results allow to propose a battery recycling process based on a countercurrent reducing leaching by citric acid in sulphuric solution.

  16. Graphene-based non-noble-metal Co/N/C catalyst for oxygen reduction reaction in alkaline solution

    Science.gov (United States)

    Niu, Kexing; Yang, Baoping; Cui, Jinfeng; Jin, Jutao; Fu, Xiaogang; Zhao, Qiuping; Zhang, Junyan

    2013-12-01

    This study develops a promising catalyst for oxygen reduction reaction (ORR) via a simple two-step heat treatment of a mixture of cobalt(II) nitrate hexahydrate (Co(NO3)2·6H2O), polyethyleneimine (PEI), and graphene oxide (GO), firstly in argon atmosphere and then in ammonia atmosphere. X-ray photoemission spectroscopy (XPS) result reveals that the catalyst has pyridinic N-dominant (46% atomic concentration among all N components) on the surface. The kinetics measurement of the catalyst in 0.1 M KOH solution using a rotating disk electrode (RDE) reveals that the catalyst (Co/N/rGO(NH3)) has high activity. Furthermore, the number of electrons exchanged during the ORR with the catalyst is determined to be ˜3.9, suggesting that the ORR is dominated by a 4e- reduction of O2 to H2O. The catalyst has good stability, and its performance is superior to the commercial Pt/C(20%) catalyst in alkaline condition, making the material a promising substitute to noble metal ORR electrocatalyst on the cathode side of fuel cells.

  17. Ni nanoparticles supported on graphene layers: An excellent 3D electrode for hydrogen evolution reaction in alkaline solution

    Science.gov (United States)

    Wang, Lixin; Li, Yao; Xia, Meirong; Li, Zhiping; Chen, Zhouhao; Ma, Zhipeng; Qin, Xiujuan; Shao, Guangjie

    2017-04-01

    Metal Ni is a plentiful resource that can actively split water toward hydrogen evolution reaction (HER) in alkaline solution, but exploiting high-efficiency Ni-based composite catalysts is still a significant assignment. Therefore, we design a catalytic material with one-step approach to co-electrodeposit Ni nanoparticles and reduced graphene oxide (rGO) sheets on a three-dimensional Ni foam. When the carbon content existed in Ni-rGO composite catalyst is 3.335 at%, the catalyst exhibits excellent activity on HER with a low Tafel slope (b = 77 mV dec-1), a high exchange current density (j0 = 3.408 mA cm-2), small overpotentials of only 36, 129, and 183 mV to drive 10, 60, and 100 mA cm-2 respectively, and high stability under the different current densities. Such remarkable hydrogen evolution performance is attributed to good electrical conductivity, large specific surface area and harmonious synergistic effect between Ni particles and rGO sheets. In addition, density functional theory (DFT) calculations explain that Ni-rGO composite material presents superior interfacial activity in adsorption/desorption of H* compared with pure Ni and rGO sheet.

  18. Electroreduction of oxygen on Vulcan carbon supported Pd nanoparticles and Pd-M nanoalloys in acid and alkaline solutions

    Energy Technology Data Exchange (ETDEWEB)

    Alexeyeva, N. [Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu (Estonia); Sarapuu, A., E-mail: ave.sarapuu@ut.ee [Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu (Estonia); Tammeveski, K. [Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu (Estonia); Vidal-Iglesias, F.J.; Solla-Gullon, J.; Feliu, J.M. [Instituto de Electroquimica, Universidad de Alicante, Apartado 99, 03080 Alicante (Spain)

    2011-07-30

    Highlights: > Electroreduction of O{sub 2} on carbon-supported Pd, PdCo and PdFe nanoparticles is studied. > Pd-based catalysts were prepared by reduction in the presence of citrate and in microemulsion. > Four-electron reduction of O{sub 2} proceeds in both acid and alkaline media. > Specific activity of PdCo and PdFe nanocatalysts was similar to that of Pd nanoparticles. - Abstract: The kinetics of O{sub 2} reduction on novel electrocatalyst materials deposited on carbon substrates were studied using the rotating disk electrode (RDE) technique. Palladium nanoparticles and Pd-M (PdCo and PdFe) nanoalloys supported on Vulcan XC-72R were prepared using two different synthetic routes. The catalyst samples were examined by transmission electron microscopy (TEM) and the average size of metal nanoparticles was determined. Electrochemical measurements were performed in 0.5 M H{sub 2}SO{sub 4} and in 0.1 M NaOH solutions. The influence of different synthetic conditions on the values of specific activity and other kinetic parameters was investigated. These parameters were determined from the Tafel plots taking into account the real electroactive area for each electrode. Pd nanoparticles and Pd-M nanoalloys exhibit significantly high electrocatalytic activity for the four-electron reduction of oxygen to water.

  19. Effect of Protein-Lipid-Salt Interactions on Sodium Availability in the Mouth and Consequent Perception of Saltiness: In Solutions.

    Science.gov (United States)

    Yucel, Umut; Peterson, Devin G

    2015-09-01

    The influence of protein-sodium interactions on the availability of sodium in the aqueous phase of liquid samples and consequently on the perception of saltiness was investigated. The aqueous effluents of casein and casein emulsion-salt solutions were monitored for sodium availability from a tongue column system. In the aqueous protein-salt solutions, increasing the protein/salt ratio from 1:1 to 5:1 or 10:1 significantly decreased the initial salt concentration in the effluent and resulted in a higher salt concentration in the effluent over time. Sensory analysis was in agreement. Samples with increased protein were rated as having significantly lower initial saltiness and a higher salty aftertaste. However, when casein was formulated as an emulsion, the initial release of sodium in the effluent was enhanced (compared to nonemulsified protein). Increasing the emulsion interfacial area (more hydrophilic segments of the protein were structured into the aqueous phase) resulted in a higher salt concentration in the aqueous phase and greater perceived saltiness intensity. In summary, protein interactions, specifically ionic, were reported as food interactions that influence salt perception and provide a basis to develop higher flavor quality low-sodium food products.

  20. Conductivity and Viscosity Measurements for Binary Lysozyme Chloride Aqueous Solution and Ternary Lysozyme-Salt-Water Solution

    CERN Document Server

    Buzatu, D; Buzatu, F D

    2004-01-01

    We use the conductimetric method, adequate to electrolytes, to determine the lysozyme charge in lys-water and ternary lys-salt-water systems. We measured also the viscosities for the above binary and ternary systems in the same conditions at pH$=4.5$ and T$=298$ K, measurements that allow us to see any effect of viscosity on cations mobilities and implicitly on the lysozyme charge. The method is illustrated for the lysozyme chloride aqueous solution system at 25$^o$ C, using the data reported here for pH$=4.5$ at 0.15, 0.6, 0.8, 1., 1.5, 2., 2.5, 3., 3.5 mM (mg/mL) lysozyme chloride concentrations. The method was also applied to ternary lys-salt-water systems in the same conditions at pH$=4.5$ and T$=25^o$ C. Ternary conductivities are reported for a mean concentration 0.6 mM of lysozyme chloride in all systems and a mean concentration 0.01, 0.025, 0.05, 0.1, 0.175, 0.2, 0.5, 0.7, 0.9, 1.2, 1.3 and 1.4 M for NaCl; 0.005, 0.01, 0.05, 0.1, 0.175, 0.2, 0.5, 0.7, 0.9, 1.2, 1.3, 1.4 and 1.5 M for KCl; 0.005, 0.01,...

  1. KARAKTERISASI FISIKOKIMIA NANOKALSIUM HASIL EKSTRAKSI TULANG IKAN NILA MENGGUNAKAN LARUTAN BASA DAN ASAM [Physicochemical Characterization of Nano Calcium from Tilapia Bone Extracted by Alkaline and Acid Solution

    Directory of Open Access Journals (Sweden)

    Vanessa Lekahena*

    2014-06-01

    Full Text Available The utilization of tilapia (Oreochromis niloticus bones as a source of natural calcium was done by alkaline (NaOH and acid (HCl extraction. The extraction process aims to soften the bones are milled using disc mill into nano sized calcium powder or nanocalcium. The objective of this research was to study the physicochemical properties of nanocalcium obtained from alkaline and acid extraction of tilapia bones. The results of physicochemical analysis properties of nanocalcium sample showed that nanocalcium extracted by alkaline solution had better properties than that of the untreated sample and nanocalcium extracted by acid solution. The results was indicated by the higher yield, brighter colors, smaller particle size, and calcium content (20.67% and phosphorus (10.09% with a ratio of Ca/P = 2.0. The Fourier Transform Infrared (FTIR spectra profile indicated the presence of phosphate group (PO43- at the bands of 469, 563, 603, 961 and 1035 cm-1, and the presence of apatite carbonate group (CO32- was indicated by intense bands at 873, 1416, 1456 and 1563 cm-1. The morphology of the sampel surface of the alkaline extracted sample was smoother, denser, and the grain size formed were relatively larger. The formed crystalline phases were HAp (hydroxyapatite, carbonate apatite type A [Ca10(PO46CO3] and B [Ca10(PO43(CO33(OH2] with crystalline degree of 78.4%.

  2. Results for the Fourth Quarter Calendar Year 2015 Tank 50H Salt Solution Sample

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-01-11

    In this memorandum, the chemical and radionuclide contaminant results from the Fourth Quarter Calendar Year 2015 (CY15) sample of Tank 50H salt solution are presented in tabulated form. The Fourth Quarter CY15 Tank 50H samples were obtained on October 29, 2015 and received at Savannah River National Laboratory (SRNL) on October 30, 2015. The information from this characterization will be used by Defense Waste Processing Facility (DWPF) & Saltstone Facility Engineering for the transfer of aqueous waste from Tank 50H to the Salt Feed Tank in the Saltstone Production Facility, where the waste will be treated and disposed of in the Saltstone Disposal Facility. This memorandum compares results, where applicable, to Saltstone Waste Acceptance Criteria (WAC) limits and targets. Data pertaining to the regulatory limits for Resource Conservation and Recovery Act (RCRA) metals will be documented at a later time per the Task Technical and Quality Assurance Plan (TTQAP) for the Tank 50H saltstone task. The chemical and radionuclide contaminant results from the characterization of the Fourth Quarter Calendar Year 2015 (CY15) sampling of Tank 50H were requested by SRR personnel and details of the testing are presented in the SRNL Task Technical and Quality Assurance Plan.

  3. Hydrogen generation in microbial reverse-electrodialysis electrolysis cells using a heat-regenerated salt solution.

    Science.gov (United States)

    Nam, Joo-Youn; Cusick, Roland D; Kim, Younggy; Logan, Bruce E

    2012-05-01

    Hydrogen gas can be electrochemically produced in microbial reverse-electrodialysis electrolysis cells (MRECs) using current derived from organic matter and salinity-gradient energy such as river water and seawater solutions. Here, it is shown that ammonium bicarbonate salts, which can be regenerated using low-temperature waste heat, can also produce sufficient voltage for hydrogen gas generation in an MREC. The maximum hydrogen production rate was 1.6 m(3) H(2)/m(3)·d, with a hydrogen yield of 3.4 mol H(2)/mol acetate at a salinity ratio of infinite. Energy recovery was 10% based on total energy applied with an energy efficiency of 22% based on the consumed energy in the reactor. The cathode overpotential was dependent on the catholyte (sodium bicarbonate) concentration, but not the salinity ratio, indicating high catholyte conductivity was essential for maximizing hydrogen production rates. The direction of the HC and LC flows (co- or counter-current) did not affect performance in terms of hydrogen gas volume, production rates, or stack voltages. These results show that the MREC can be successfully operated using ammonium bicarbonate salts that can be regenerated using conventional distillation technologies and waste heat making the MREC a useful method for hydrogen gas production from wastes.

  4. Hydrogen Generation in Microbial Reverse-Electrodialysis Electrolysis Cells Using a Heat-Regenerated Salt Solution

    KAUST Repository

    Nam, Joo-Youn

    2012-05-01

    Hydrogen gas can be electrochemically produced in microbial reverse-electrodialysis electrolysis cells (MRECs) using current derived from organic matter and salinity-gradient energy such as river water and seawater solutions. Here, it is shown that ammonium bicarbonate salts, which can be regenerated using low-temperature waste heat, can also produce sufficient voltage for hydrogen gas generation in an MREC. The maximum hydrogen production rate was 1.6 m3 H2/m3·d, with a hydrogen yield of 3.4 mol H2/mol acetate at a salinity ratio of infinite. Energy recovery was 10% based on total energy applied with an energy efficiency of 22% based on the consumed energy in the reactor. The cathode overpotential was dependent on the catholyte (sodium bicarbonate) concentration, but not the salinity ratio, indicating high catholyte conductivity was essential for maximizing hydrogen production rates. The direction of the HC and LC flows (co- or counter-current) did not affect performance in terms of hydrogen gas volume, production rates, or stack voltages. These results show that the MREC can be successfully operated using ammonium bicarbonate salts that can be regenerated using conventional distillation technologies and waste heat making the MREC a useful method for hydrogen gas production from wastes. © 2012 American Chemical Society.

  5. The Influence of Calcium Chloride Salt Solution on the Transport Properties of Cementitious Materials

    Directory of Open Access Journals (Sweden)

    Yaghoob Farnam

    2015-01-01

    Full Text Available The chemical interaction between calcium chloride (CaCl2 and cementitious binder may alter the transport properties of concrete which are important in predicting the service life of infrastructure elements. This paper presents a series of fluid and gas transport measurements made on cementitious mortars before and after exposure to various solutions with concentrations ranging from 0% to 29.8% CaCl2 by mass. Fluid absorption, oxygen diffusivity, and oxygen permeability were measured on mortar samples prepared using Type I and Type V cements. Three primary factors influence the transport properties of mortar exposed to CaCl2: (1 changes in the degree of saturation, (2 calcium hydroxide leaching, and (3 formation of chemical reaction products (i.e., Friedel’s salt, Kuzel’s salt, and calcium oxychloride. It is shown that an increase in the degree of saturation decreases oxygen permeability. At lower concentrations (~12%, the formation of chemical reaction products (mainly calcium oxychloride is a dominant factor decreasing the fluid and gas transport in concrete.

  6. Isolation and characterization of coagulant extracted from Moringa oleifera seed by salt solution.

    Science.gov (United States)

    Okuda, T; Baes, A U; Nishijima, W; Okada, M

    2001-02-01

    It is known that M. oleifera contains a natural coagulant in the seeds. In our previous research, the method using salt water to extract the active coagulation component from M. oleifera seeds was developed and compared with the conventional method using water. In this research, the active coagulation component was purified from a NaCl solution crude extract of Moringa oleifera seeds. The active component was isolated and purified from the crude extract through a sequence of steps that included salting-out by dialysis, removal of lipids and carbohydrates by homogenization with acetone, and anion exchange. Specific coagulation activity of the active material increased up to 34 times more than the crude extract after the ion exchange. The active component was not the same as that of water extract. The molecular weight was about 3000 Da. The Lowry method and the phenol-sulfuric acid method indicated that the active component was neither protein nor polysaccharide. The optimum pH of the purified active component for coagulation of turbidity was pH 8 and above. Different from the conventional water extracts, the active component can be used for waters with low turbidity without increase in the dissolved organic carbon concentration.

  7. Geobacter sp. SD-1 with enhanced electrochemical activity in high-salt concentration solutions.

    Science.gov (United States)

    Sun, Dan; Call, Douglas; Wang, Aijie; Cheng, Shaoan; Logan, Bruce E

    2014-12-01

    An isolate, designated strain SD-1, was obtained from a biofilm dominated by Geobacter sulfurreducens in a microbial fuel cell. The electrochemical activity of strain SD-1 was compared with type strains, G. sulfurreducens PCA and Geobacter metallireducens GS-15, and a mixed culture in microbial electrolysis cells. SD-1 produced a maximum current density of 290 ± 29 A m−3 in a high-concentration phosphate buffer solution (PBS-H, 200 mM). This current density was significantly higher than that produced by the mixed culture (189 ± 44 A m−3) or the type strains (Geobacter strains and mixed cultures in terms of its salt tolerance.

  8. Solubility and reactivity of peroxyacetyl nitrate (PAN) in dilute aqueous salt solutions and in sulphuric acid

    Science.gov (United States)

    Frenzel, A.; Kutsuna, S.; Takeuchi, K.; Ibusuki, T.

    The loss rates of PAN in several dilute aqueous salt solutions (NaBr, Na 2SO 3, KI, NaNO 2, FeCl 3, and FeSO 4) and in sulphuric acid were measured at 279 K with a simple bubbler experiment. They are little different from that in pure water. For 5 M sulphuric acid hydrolysis and solubility were determined in the temperature range of 243-293 K. The hydrolysis rate kh=3.2×10 -4 s -1 at 293 K is close to that in water. The observed temperature dependence of the Henry's Law constant H=10- 6.6±0.6exp((4780±420)/T) M atm -1 leads to enthalpy and entropy of solvation Δ Hsolv=-39.7±3.5 kJ mol -1 and Δ Ssolv=-126±11 J mol -1 K -1, respectively.

  9. Characteristics and quantitative of negative ion in salt aqueous solution by Raman spectroscopy at -170℃

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The results from Raman spectroscopy analysis of salt aqueous solutions at -170℃ demonstrate that for those clearly sharp iron peaks whose Raman wavenumber is close to each other such as and , their original shape could be restorable by the stripping technique, and that ice's sharp characteristic peak (3090-3109 cm-1) is steady, while the spectrum band of the complex compound (nCl--[H+-OH-]n) chlorine ion combined chemically with water molecule is 3401-3413 cm-1. On the other hand, the research shows that the higher the negative iron concentration, the stronger its Raman characteristic peak intensity and the smaller the ice's. Based on the number of data and theoretical work, the strong correlation of the molar concentration of negative ion with the band area ratio is built up. Moreover, the developed Raman method is successfully used in the component analysis of the field fluid inclusions from Silurian sandstone in Tarim basin.

  10. Modeling of Dielectric Properties of Aqueous Salt Solutions with an Equation of State

    DEFF Research Database (Denmark)

    Maribo-Mogensen, Bjørn; Kontogeorgis, Georgios; Thomsen, Kaj

    2013-01-01

    The static permittivity is the most important physical property for thermodynamic models that account for the electrostatic interactions between ions. The measured static permittivity in mixtures containing electrolytes is reduced due to kinetic depolarization and reorientation of the dipoles...... in the electrical field surrounding ions. Kinetic depolarization may explain 25–75% of the observed decrease in the permittivity of solutions containing salts, but since this is a dynamic property, this effect should not be included in the thermodynamic modeling of electrolytes. Kinetic depolarization has, however...... to associating mixtures. Wertheim’s association model as formulated in the statistical associating fluid theory is used to account for hydrogen-bonding molecules and ion–solvent association. Finally, we compare the Debye–Hückel Helmholtz energy obtained using an empirical model with the new physical model...

  11. Electrochemical quartz crystal microbalance study on Au-supported Pt adlayers for electrocatalytic oxidation of methanol in alkaline solution

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Underpotential deposition(UPD) of Cu on an Au electrode followed by redox replacement reaction(RRR) of CuUPD with a Pt source(H2PtCl6 or K2PtCl4) yielded Au-supported Pt adlayers(for short,Pt(CuUPD-Pt4+)n/Au for H2PtCl6,or Pt(CuUPD-Pt2+)n/Au for K2PtCl4,where n denotes the number of UPD-redox replacement cycles).The electrochemical quartz crystal microbalance(EQCM) technique was used for the first time to quantitatively study the fabricated electrodes and estimate their mass-normalized specific electrocatalytic activity(SECA) for methanol oxidation in alkaline solution.In comparison with Pt(CuUPD-Pt2+)n/Au,Pt(CuUPD-Pt4+)n/Au exhibited a higher electrocatalytic activity,and the maximum SECA was obtained to be as high as 35.7 mA ?g?1 at Pt(CuUPD-Pt4+)3/Au.The layer-by-layer architecture of Pt atoms on Au is briefly discussed based on the EQCM-revealed redox replacement efficiency,and the calculated distribution percentages of bare Au sites agree with the experimental results deduced from the charge under the AuOx-reduction peaks.The EQCM is highly recommended as an efficient technique to quantitatively examine various electrode-supported catalyst adlayers,and the highly efficient catalyst adlayers of noble metals are promising in electrocatalysis relevant to biological,energy and environmental sciences and technologies.

  12. Impedance measurements in different alkaline solutions on an oxygen-evolving Lasub(0. 5)Srsub(0. 5)CoO/sub 3/ electrode

    Energy Technology Data Exchange (ETDEWEB)

    Willems, H.; Moers, M.; Broers, G.H.J.; Wit, J.H.W. de

    1985-10-25

    It was found that the oxygen evolution reaction on Lasub(0.5)Srsub(0.5)CoO/sub 3/ in strong alkaline solutions has a Tafel slope of proportional 60 mV/dec and a reaction order at constant overpotential with respect to the KOH activity of 0.6-0.8. From impedance measurements differential Tafel slopes were calculated and were found to be proportional 60 mV/dec at overpotentials >250 mV. Effective capacitances having a broad maximum at an overpotential of about 200 mV in all alkaline solutions were calculated. The effective capacitance increased with increasing KOH concentration. Furthermore, the material decomposed at the surface when exposed to strong oxygen evolution. From the results a modified Krasil'shchikov reaction path is analysed. (orig.).

  13. Complex electronic waste treatment - An effective process to selectively recover copper with solutions containing different ammonium salts.

    Science.gov (United States)

    Sun, Z H I; Xiao, Y; Sietsma, J; Agterhuis, H; Yang, Y

    2016-11-01

    Recovery of valuable metals from electronic waste has been highlighted by the EU directives. The difficulties for recycling are induced by the high complexity of such waste. In this research, copper could be selectively recovered using an ammonia-based process, from industrially processed information and communication technology (ICT) waste with high complexity. A detailed understanding on the role of ammonium salt was focused during both stages of leaching copper into a solution and the subsequent step for copper recovery from the solution. By comparing the reactivity of the leaching solution with different ammonium salts, their physiochemical behaviour as well as the leaching efficiency could be identified. The copper recovery rate could reach 95% with ammonium carbonate as the leaching salt. In the stage of copper recovery from the solution, electrodeposition was introduced without an additional solvent extraction step and the electrochemical behaviour of the solution was figured out. With a careful control of the electrodeposition conditions, the current efficiency could be improved to be 80-90% depending on the ammonia salts and high purity copper (99.9wt.%). This research provides basis for improving the recyclability and efficiency of copper recovery from such electronic waste and the whole process design for copper recycling.

  14. Excellent dynamic stability under saturated salt solution for aqueous quantum dots capped by multi-branched ligands

    Science.gov (United States)

    Xu, Jingkun; Xu, Shuhong; Lv, Changgui; Wang, Chunlei; Cui, Yiping

    2016-09-01

    Preparing quantum dots (QDs) with strong stability against salts is extremely important in some environments with ultrahigh salts concentration, such as the oil exploitation, wastewater treatment and biological markers. In this paper, we reported a simple new method to prepared highly stable QDs by using multi-branched ligands. Our results suggested that multi-branched ligands-capped QDs have extremely good dynamic stability even in salt-saturated solution. Unlike to traditional dynamic stability theory, which considers the electrostatic repulsion of QDs dominant QD stability, the current work found a new determined factor: the steric hindrance of ligand structure. The high steric hindrance effect of multi-branched ligands can maintain the single dispersity of QDs even at extremely low electrostatic repulsion. As a result, QDs with ultrahigh stability against salts can be realized.

  15. Enzymatically mediated bioprecipitation of heavy metals from industrial wastes and single ion solutions by mammalian alkaline phosphatase.

    Science.gov (United States)

    Chaudhuri, Gouri; Shah, Gaurav A; Dey, Pritam; S, Ganesh; Venu-Babu, P; Thilagaraj, W Richard

    2013-01-01

    The study was aimed at investigating the potential use of calf intestinal alkaline phosphatase (CIAP) enzyme in the removal of heavy metals (Cd(2+), Ni(2+), Co(2+) and Cr(3+/6+)) from single ion solutions as well as tannery and electroplating effluents. CIAP mediated bioremediation (white biotechnology) is a novel technique that is eco-friendly and cost effective unlike the conventional chemical technologies. Typical reactions containing the enzyme (CIAP) and p-nitrophenyl phosphate (pNPP) as substrate in Tris-HCl buffer (pH 8 and 11) and either single ion metal solutions (250 ppm and 1000 ppm) or effluents from tannery or electroplating industry were incubated at 37°C for 30 min, 60 min and 120 min. The inorganic phosphate (P(i)) generated due to catalytic breakdown of pNPP complexes free metal ions as metal-phosphate and the amount of metal precipitated was derived by estimating the reduction in the free metal ion present in the supernatant of reactions employing atomic absorption spectrophotometer (AAS). Better precipitation of metal was obtained at pH 11 than at pH 8 and between the two concentrations of different metals tested, an initial metal concentration of 250 ppm in the reaction gave more precipitation than with 1000 ppm. Experimental data showed that at pH 11, the percentage of removal of metal ions (for an initial concentration of 250 ppm) was in the following order: Cd(2+) (80.99%) > Ni(2+) (64.78%) > Cr(3+) > (46.15%) > Co(2+) (36.47%) > Cr(6+) (32.33%). The overall removal of Cr(3+) and Cr(6+) from tannery effluent was 32.77% and 37.39% respectively in 120 min at pH 11. Likewise, the overall removal of Cd(2+), Co(2+) and Ni(2+) from electroplating effluent was 50.42%, 13.93% and 38.64% respectively in 120 min at pH 11. The study demonstrates that bioprecipitation by CIAP may be a viable and environmental friendly method for clean-up of heavy metals from tannery and electroplating effluents.

  16. Can mothers safely prepare labon-gur salt-sugar solution after demonstration in a diarrhoeal hospital?

    DEFF Research Database (Denmark)

    Islam, M A; Kofoed, Poul-Erik; Begum, S

    1992-01-01

    and the attendants at ICDDR, Bangladesh. To evaluate performances, 150 mothers were asked to measure labon and gur by finger pinch and first method and 100 mothers measured half a seer of water to prepare labon-gur SSS, shortly after the demonstration sessions. 4.0% of the samples exceeded the upper safety limit......Home-based salt-sugar solution (SSS) prepared with labon (locally produced sea salt) and gur (unrefined brown sugar) has been recommended as a cheap, locally available and a simple tool to prevent and treat diarrhoeal dehydration. Preparation of labon-gur SSS is demonstrated to the patients...... while 1.3% exceeded the upper danger limit for salt and 98.7% samples of gur were within safe and effective range. Mothers' performances were not different with regard to their educational status and prior practice at home. 80% knew about the solution before coming to the hospital and 45% had utilized...

  17. Line emissions from sonoluminescence in aqueous solutions of halide salts without noble gases

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Jinfu, E-mail: liang.shi2007@163.com [The Key Laboratory of Modern Acoustics, Ministry of Education, Institution of Acoustics, Nanjing University, Nanjing 210093 (China); School of Physics and Electronic Science, Guizhou Normal University, Guiyang 550001 (China); Chen, Weizhong, E-mail: wzchen@nju.edu.cn [The Key Laboratory of Modern Acoustics, Ministry of Education, Institution of Acoustics, Nanjing University, Nanjing 210093 (China); Zhou, Chao; Cui, Weicheng; Chen, Zhan [The Key Laboratory of Modern Acoustics, Ministry of Education, Institution of Acoustics, Nanjing University, Nanjing 210093 (China)

    2015-02-20

    Line emissions of trivalent terbium (Tb{sup 3+}) ion were observed from single-bubble sonoluminescence (SL) in an aqueous solution of terbium chloride (TbCl{sub 3}) that contained no noble gas. In addition, sodium (Na) lines were observed in multi-bubble SL in aqueous solutions of various halide salts that contained no noble gas. These observations show that the halide ions, such as Cl{sup −}, Br{sup −}, and I{sup −}, help for line emissions as the noble gases. The intensity of a line emission depends on both the chemical species produced by cavitation bubbles and the temperature of SL bubble that responds to the driving ultrasound pressure. With the increase of driving pressure, some line emissions attached to the continuous spectrum may become increasingly clear, while other line emissions gradually become indistinct. - Highlights: • Line emissions of Tb(III) ions were observed without the presence of noble gases. • The halide ions help to generate a line emission during sonoluminescence. • The intensity of a line emission mainly depends on the bubble's temperature. • The definition of a line emission is related to the temperature of caviation bubble and the kind of host liquid.

  18. Surface-induced liquid-gas transition in salt-free solutions of model charged colloids.

    Science.gov (United States)

    Budkov, Yu A; Frolov, A I; Kiselev, M G; Brilliantov, N V

    2013-11-21

    We report a novel phenomenon of a surface-induced phase transition in salt-free solutions of charged colloids. We develop a theory of this effect and confirm it by Molecular Dynamics simulations. To describe the colloidal solution we apply a primitive model of electrolyte with a strong asymmetry of charge and size of the constituent particles - macroions and counterions. To quantify interactions of the colloidal particles with the neutral substrate we use a short-range potential which models dispersion van der Waals forces. These forces cause the attraction of colloids to the surface. We show that for high temperatures and weak attraction, only gradual increase of the macroion concentration in the near-surface layer is observed with increase of interaction strength. If however temperature drops below some threshold value, a new dense (liquid) phase is formed in the near-surface layer. It can be interpreted as a surface-induced first-order phase transition with a critical point. Using an appropriately adopted Maxwell construction, we find the binodal. Interestingly, the observed near-surface phase transition can occur at the absence of the bulk phase transition and may be seemingly classified as prewetting transition. The reported effect could be important for various technological applications where formation of colloidal particle layers with the desired properties is needed.

  19. Influence of acid and alkaline sources on optical, structural and photovoltaic properties of CdSe nanoparticles precipitated from aqueous solution

    Science.gov (United States)

    Coria-Monroy, C. Selene; Sotelo-Lerma, Mérida; Hu, Hailin

    2016-06-01

    CdSe is a widely researched material for photovoltaic applications. One of the most important parameters of the synthesis is the pH value, since it determines the kinetics and the mechanism of the reaction and in consequence, the optical and morphological properties of the products. We present the synthesis of CdSe in solution with strict control of pH and the comparison of ammonia and KOH as alkaline sources and diluted HCl as acid medium. CdSe formation was monitored with photoluminescence emission spectra (main peak in 490 nm, bandgap of CdSe nanoparticles). XRD patterns indicated that CdSe nanoparticles are mainly of cubic structure for ammonia and HCl, but the hexagonal planes appear with KOH. Product yield decreases with pH and also decreases with KOH at constant pH value since ammonia has a double function, as complexing agent and alkaline source. Changes in morphology were observed in SEM images as well with the different alkaline source. The effect of alkaline sources on photovoltaic performance of hybrid organic solar cells with CdSe and poly(3-hexylthiophene) as active layers was clearly observed, indicating the importance of synthesis conditions on optoelectronic properties of promising semiconductor nanomaterials for solar cell applications.

  20. Assessment of drug salt release from solutions, suspensions and in situ suspensions using a rotating dialysis cell

    DEFF Research Database (Denmark)

    Parshad, Henrik; Frydenvang, Karla; Liljefors, Tommy

    2003-01-01

    A rotating dialysis cell consisting of a small (10 ml) and a large compartment (1000 ml) was used to study the release of drug salt (bupivacaine 9-anthracene carboxylate) from (i). solutions, (ii). suspensions and (iii). in situ formed suspensions. Initial release experiments from suspensions...

  1. Chemical equilibrium of hydrogen and aqueous solutions of 1 : 1 bicarbonate and formate salts with a common cation

    NARCIS (Netherlands)

    Engel, D.C.; Versteeg, G.F.; Swaaij, W.P.M. van

    1997-01-01

    The chemical equilibrium of hydrogen and aqueous solutions of 1:1 bicarbonate and formate salts with a common cation has been investigated in an intensively stirred batch reactor: MHCO3(aq) + H2(aq) ↔ MOOCH(aq) + H2O(l) This was accomplished for the sodium (M = Na), potassium (M = K) and ammonium (M

  2. A new method for preparation of magnetite from iron oxyhydroxide or iron oxide and ferrous salt in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Kahani, S.A. [Department of Chemistry, Faculty of Science, University of Kashan, Kashan 87317-51167 (Iran, Islamic Republic of)], E-mail: Kahani@kashanu.ac.ir; Jafari, M. [Department of Chemistry, Faculty of Science, University of Kashan, Kashan 87317-51167 (Iran, Islamic Republic of)

    2009-07-15

    In this study, a new method is proposed for the preparation of Fe{sub 3}O{sub 4} from iron oxyhydroxides (goethite, akaganeite, lepidocrocite, feroxyhyte and ferrihydrite) or iron oxide (hematite) and ferrous salt in aqueous solution. The product is magnetite with various particle sizes. Products are characterized by X-ray powder diffraction, IR spectra and vibrating sample magnetometery.

  3. On the feasibility of near infrared spectroscopy to detect contaminants in water using single salt solutions as model systems.

    Science.gov (United States)

    Gowen, A A; Marini, F; Tsuchisaka, Y; De Luca, S; Bevilacqua, M; O'Donnell, C; Downey, G; Tsenkova, R

    2015-01-01

    This research work evaluates the feasibility of NIRS to detect contaminants in water using single salt solutions as model systems. Previous research has indicated the potential of near infrared spectroscopy (NIRS) for detecting solutes in water; however, a comprehensive investigation of the limit of detection of this technique has not been carried out. Near infrared transmittance spectra of aqueous salt solutions in the concentration range 0.002-0.1 mol L(-1) (equivalent to 117-13,334 ppm or 0.0001-0.01% mass/mass) were investigated. The first overtone region of the near infrared spectrum (1300-1600 nm) was found to be the most effective wavelength range for prediction of salt concentration in aqueous solutions. Calibration models built using this wavelength range and employing the extended multiplicative scatter spectral pre-treatment resulted in root mean squared error of prediction values ranging from 0.004 to 0.01 mol L(-1). The limit of detection (LOD) was estimated to be of the order of 0.1% (mass/mass) or 1000 ppm. Within the framework of Aquaphotomics, it was possible to examine the effect of different salts on the NIR spectra of water in the first overtone range. Our results were confirmed through test experiments at various geographical locations employing dispersive and Fourier transform type NIRS instruments.

  4. Salt-enhanced removal of 2-ethyl-1-hexanol from aqueous solutions by adsorption on activated carbon.

    Science.gov (United States)

    Chang, Ganggang; Bao, Zongbi; Zhang, Zhiguo; Xing, Huabin; Su, Baogen; Yang, Yiwen; Ren, Qilong

    2013-12-15

    2-Ethyl-1-hexanol has extensive industrial applications in solvent extraction, however, in view of its potential pollution to environment, the removal and recovery of 2-ethyl-1-hexanol is considered an essential step toward its sustainable use in the future. In this work, we report the removal of 2-ethyl-1-hexanol from aqueous solutions containing salts in high concentrations by adsorption on a coal-based activated carbon. Adsorption thermodynamics showed that the experimental isotherms were conformed well to the Langmuir equation. Also it was found that inorganic salts, i.e. MgCl2 and CaCl2 in high concentration significantly enhanced the adsorption capacity from 223 mg/g in the deionized water to 277 mg/g in a saline water. This phenomenon of adsorption enhancement could be ascribed to the salt-out effect. Kinetic analysis indicated that adsorption kinetics follows the pseudo-second-order equation and the adsorption rate constants increase with the salt concentration. The dynamic breakthrough volume and adsorbed amount of 2-ethyl-1-hexanol were significantly elevated when the salt is present in the water. The dynamic saturated adsorption amount increased from 218.3mg/g in the deionized water to 309.5mg/g in a salt lake brine. The Tomas model was well applied to predict the breakthrough curves and determine the characteristics parameters of the adsorption column.

  5. SAVANNAH RIVER SITE INCIPIENT SLUDGE MIXING IN RADIOACTIVE LIQUID WASTE STORAGE TANKS DURING SALT SOLUTION BLENDING

    Energy Technology Data Exchange (ETDEWEB)

    Leishear, R.; Poirier, M.; Lee, S.; Steeper, T.; Fowley, M.; Parkinson, K.

    2011-01-12

    This paper is the second in a series of four publications to document ongoing pilot scale testing and computational fluid dynamics (CFD) modeling of mixing processes in 85 foot diameter, 1.3 million gallon, radioactive liquid waste, storage tanks at Savannah River Site (SRS). Homogeneous blending of salt solutions is required in waste tanks. Settled solids (i.e., sludge) are required to remain undisturbed on the bottom of waste tanks during blending. Suspension of sludge during blending may potentially release radiolytically generated hydrogen trapped in the sludge, which is a safety concern. The first paper (Leishear, et. al. [1]) presented pilot scale blending experiments of miscible fluids to provide initial design requirements for a full scale blending pump. Scaling techniques for an 8 foot diameter pilot scale tank were also justified in that work. This second paper describes the overall reasons to perform tests, and documents pilot scale experiments performed to investigate disturbance of sludge, using non-radioactive sludge simulants. A third paper will document pilot scale CFD modeling for comparison to experimental pilot scale test results for both blending tests and sludge disturbance tests. That paper will also describe full scale CFD results. The final paper will document additional blending test results for stratified layers in salt solutions, scale up techniques, final full scale pump design recommendations, and operational recommendations. Specifically, this paper documents a series of pilot scale tests, where sludge simulant disturbance due to a blending pump or transfer pump are investigated. A principle design requirement for a blending pump is UoD, where Uo is the pump discharge nozzle velocity, and D is the nozzle diameter. Pilot scale test results showed that sludge was undisturbed below UoD = 0.47 ft{sup 2}/s, and that below UoD = 0.58 ft{sup 2}/s minimal sludge disturbance was observed. If sludge is minimally disturbed, hydrogen will not be

  6. Diclofenac Salts, VIII. Effect of the Counterions on the Permeation through Porcine Membrane from Aqueous Saturated Solutions

    Directory of Open Access Journals (Sweden)

    Cristina Cavallari

    2012-09-01

    Full Text Available The following bases: monoethylamine (EtA, diethylamine (DEtA, triethylamine (TEtA, monoethanolamine (MEA, diethanolamine (DEA, triethanolamine (TEA, pyrrolidine (Py, piperidine (Pp, morpholine (M, piperazine (Pz and their N-2-hydroxyethyl (HE analogs were employed to prepare 14 diclofenac salts. The salts were re-crystallized from water in order to obtain forms that are stable in the presence of water. Vertical Franz-type cells with a diffusional surface area of 9.62 cm2 were used to study the permeation of these diclofenac salts from their saturated solutions through an internal pig ear membrane. The receptor compartments of the cells contained 100 mL of phosphate buffer (pH 7.4; a saturated solution (5 mL of each salt was placed in the donor compartment, thermostated at 37 °C. Aliquots were withdrawn at predetermined time intervals over 8 h and then immediately analyzed by HPLC. Fluxes were determined by plotting the permeated amount, normalized for the membrane surface area versus time. Permeation coefficients were obtained dividing the flux values J by the concentration of the releasing phase—that is, water solubility of each salt. Experimental results show that fluxes could be measured when diclofenac salts with aliphatic amines are released from a saturated aqueous solution. Different chemical species (acid, anion, ion pairs contribute to permeation of the anti-inflammatory agent even though ion-pairs could be hypothesized to operate to a greater extent. Permeation coefficients were found higher when the counterion contains a ring; while hydroxy groups alone do not appear to play an important role, the ring could sustain permeation, disrupting the organized domains of the membrane.

  7. Development of chemiluminescence method for determination of 10-hydroxycamptothecin based on luminol-[Ag(HIO₆)₂]⁵⁻ reaction in alkaline solution.

    Science.gov (United States)

    Sun, Hanwen; Chen, Peiyun; Shi, Shasha; Li, Liqing

    2011-01-01

    A novel chemiluminescence (CL) method was developed for the determination of 10-hydroxycamptothecin(HCPT) based on the CL reaction between [Ag(HIO₆)₂]⁵⁻ and luminol in alkaline solution. CL emission of Ag(III) complex-luminol in alkaline medium was very different from that in acidic medium. A possible mechanism of enhanced CL emission was suggested. The enhanced effect of HCPT on CL emission of the [Ag(HIO₆)₂]⁵⁻-luminol system was found. The enhanced degree of CL emission was proportional to HCPT concentration. The effect of the reaction conditions on CL emission was examined. Under optimal conditions, the limit of detection was 6.5 × 10⁻⁹ g mL⁻¹. The proposed method was applied for the determination of HCPT in real samples with the recoveries of 93.2-109% with the RSD of 1.7-3.3%.

  8. G eobacter sp. SD-1 with enhanced electrochemical activity in high-salt concentration solutions

    KAUST Repository

    Sun, Dan

    2014-07-16

    © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd. Summary: An isolate, designated strain SD-1, was obtained from a biofilm dominated by Geobacter sulfurreducens in a microbial fuel cell. The electrochemical activity of strain SD-1 was compared with type strains, G.sulfurreducensPCA and Geobacter metallireducensGS-15, and a mixed culture in microbial electrolysis cells. SD-1 produced a maximum current density of 290±29Am-3 in a high-concentration phosphate buffer solution (PBS-H, 200mM). This current density was significantly higher than that produced by the mixed culture (189±44Am-3) or the type strains (<70Am-3). In a highly saline water (SW; 50mM PBS and 650mM NaCl), current by SD-1 (158±4Am-3) was reduced by 28% compared with 50mM PBS (220±4Am-3), but it was still higher than that of the mixed culture (147±19Am-3), and strains PCA and GS-15 did not produce any current. Electrochemical tests showed that the improved performance of SD-1 was due to its lower charge transfer resistance and more negative potentials produced at higher current densities. These results show that the electrochemical activity of SD-1 was significantly different than other Geobacter strains and mixed cultures in terms of its salt tolerance.

  9. The structure and terahertz dynamics of water confined in nanoscale pools in salt solutions.

    Science.gov (United States)

    Turton, David A; Corsaro, Carmelo; Candelaresi, Marco; Brownlie, Angela; Seddon, Ken R; Mallamace, Francesco; Wynne, Klaas

    2011-01-01

    The behaviour of liquid water below its melting point is of great interest as it may hold clues to the properties of normal liquid water and of water in and on the surfaces of biomolecules. A second critical point, giving rise to a polyamorphic transition between high and low density water, may be hidden in the supercooled region but cannot be observed directly. Here it is shown that water can be locked up in nano-pools or worm-like structures using aqueous LiCl salt solutions and can be studied with terahertz spectroscopies. Very high dynamic range ultrafast femtosecond optical Kerr effect (OKE) spectroscopy is used to study the temperature-dependent behaviour of water in these nano-pools on timescales from 10 fs to 4 ns. These experiments are complemented by temperature-dependent nuclear magnetic resonance (NMR) diffusion measurements, concentration-dependent Fourier-transform infrared (FTIR) measurements, and temperature-dependent rheology. It is found that liquid water in the nanoscale pools undergoes a fragile-to-strong transition at about 220 K associated with a sharp increase in the inhomogeneity of translational dynamics.

  10. Cations extraction of sandy-clay soils from cavado valley, portugal, using sodium salts solutions

    Directory of Open Access Journals (Sweden)

    Silva João Eudes da

    2002-01-01

    Full Text Available Cases of contamination by metals in the water wells of the Cavado Valley in north-west Portugal can be attributed to the heavy leaching of clay soils due to an excess of nitrogen resulting from the intensive use of fertilisers in agricultural areas. This work focuses on the natural weathering characteristics of soils, particularly the clay material, through the study of samples collected near the River Cavado. Samples taken from various sites, after physico-chemical characterisation, were subjected to clay dissolution tests, using sodium salts of different ionic forces, to detect the relationship between certain physico-chemical parameters of water, such as pH, nitrate, chloride and sulphate content, in the dissolution of clay and the subsequent extraction of such cations as Al, Fe and K. In acidic sandy clay soils, the mineralogical composition of which was characterised by a predominance of quartz, micas, kaolinite and K-feldspars, decreases of the clay material/water pH ratio increases dissolution of the micaceous and K-feldspars phases. The presence of nitrates in the aqueous solution apparently advanced the extraction of all three cations Al, Fe and K. The specific surface area of the clay material showed a significant correlation with the main kinetic parameters of cation extraction.

  11. Salting-Out of Methane in the Aqueous Solutions of Urea and Glycine-Betaine.

    Science.gov (United States)

    Dixit, Mayank Kumar; Siddique, Asrar A; Tembe, B L

    2015-08-27

    We have studied the hydrophobic association and solvation of methane molecules in aqueous solutions of urea and glycine betaine (GB). We have calculated the potentials of mean force (PMFs) between methane molecules in water, aqueous GB, aqueous urea and aqueous urea-GB mixtures. The PMFs and equilibrium constants indicate that both urea and GB increase the hydrophobic association of methane. Calculation of thermodynamic parameters shows that the association of methane is stabilized by entropy whereas solvation is favored by enthalpy. In the case of the water-urea-GB mixture, both hydrophobic association and solvation are stabilized by entropy. From the investigation of radial distribution functions, running coordination numbers and excess coordination numbers, we infer that both urea and GB are preferentially excluded from methane surface in the mixtures of osmolytes and methane is preferentially solvated by water molecules in all the mixtures. The favorable exclusion of both urea and GB from the methane surface suggests that both urea and GB increase the interaction between methane molecules, i.e., salting-out of methane. We observe that addition of both urea and GB to water enhances local water structure. The calculated values of diffusion constants of water also suggest enhanced water-water interactions in the presence of urea and GB. The calculated free energies of methane in these mixtures show that methane is less soluble in the mixtures of urea and GB than in water. The data on solvation free energies support the observations obtained from the PMFs of methane molecules.

  12. In vitro corrosion of ZEK100 plates in Hank's Balanced Salt Solution

    Directory of Open Access Journals (Sweden)

    Waizy Hazibullah

    2012-03-01

    Full Text Available Abstract Background In recent years magnesium alloys have been intensively investigated as potential resorbable materials with appropriate mechanical and corrosion properties. Particularly in orthopedic research magnesium is interesting because of its mechanical properties close to those of natural bone, the prevention of both stress shielding and removal of the implant after surgery. Methods ZEK100 plates were examined in this in vitro study with Hank's Balanced Salt Solution under physiological conditions with a constant laminar flow rate. After 14, 28 and 42 days of immersion the ZEK100 plates were mechanically tested via four point bending test. The surfaces of the immersed specimens were characterized by SEM, EDX and XRD. Results The four point bending test displayed an increased bending strength after 6 weeks immersion compared to the 2 week group and 4 week group. The characterization of the surface revealed the presence of high amounts of O, P and Ca on the surface and small Mg content. This indicates the precipitation of calcium phosphates with low solubility on the surface of the ZEK100 plates. Conclusions The results of the present in vitro study indicate that ZEK100 is a potential candidate for degradable orthopedic implants. Further investigations are needed to examine the degradation behavior.

  13. Salting-out of methane in the aqueous solutions of urea and sarcosine

    Indian Academy of Sciences (India)

    M K Dixit; Anupam Chatterjee; B L Tembe

    2016-04-01

    Hydrophobic association and solvation of methane molecules in aqueous solutions of urea and sarcosine (sa) have been studied using MD simulations. The potentials of mean force (PMFs) between methane molecules in water, water-sa, water-urea and water-urea-sa mixtures show an enhancement of methane association on the addition of these osmolytes. These observations are well supported by calculation of equilibrium constants. Calculation of thermodynamic parameters shows that the association of methane is stabilized by entropy and favored by enthalpy. The hydrophobic solvation of methane is stabilized by enthalpy and destabilized by entropy. The calculated solvation free energies of methane in these mixtures show that methane is less soluble in the mixtures of urea and sarcosine than in water. The solubility is the least in the water-urea-sa mixture. Analysis of distributions of solvent and co-solvent around methane suggests that the local densities of both urea and sarcosine are diminished around the methane in the mixtures of these osmolytes. The selective reduction of both urea and sarcosine from methane surface suggests that both urea and sarcosine push methane molecules towards water and increase the interaction between methane molecules i.e., salting-out of methane.

  14. SANS from Salt-Free Aqueous Solutions of Hydrophilic and Highly Charged Star-Branched Polyelectrolytes

    Directory of Open Access Journals (Sweden)

    François Boué

    2016-06-01

    Full Text Available Scattering functions of sodium sulfonated polystyrene (NaPSS star-branched polyelectrolytes with high sulfonation degrees were measured from their salt-free aqueous solutions, using the Small Angle Neutron Scattering (SANS technique. Whatever the concentration c, they display two maxima. The first, of abscissa q1*, is related to a position order between star cores and scales as q1* ∝ c1/3. The second, of abscissa q2*, is also observed in the scattering function of a semi-dilute solution of NaPSS linear polyelectrolytes. In the dilute regime (c < c*, non-overlapping stars, peak abscissa does not depend on concentration c and is just an intramolecular characteristic associated with the electrostatic repulsion between arms of the same star. In the semi-dilute regime, due to the star interpenetration, the scattering function – through the peak position, reflects repulsion between arms of the same star or of different stars. The c threshold between these distinct c-dependencies of q2* in the dilute and semi-dilute regimes is estimated as c*. Just as simple is the measurement of the geometrical radius R of the star obtained from the q1* value at c* through the relation 2R = 2π/q1*. By considering NaPSS stars of the same functionality with different degrees of polymerization per arm Na, we find R scaling linearly with Na, suggesting an elongated average conformation of the arms. This is in agreement with theoretical predictions and simulations. Meanwhile the value of q2* measured in the dilute regime does not allow any inhomogeneous counterion distribution inside the stars to be revealed.

  15. Self-assembly of micelles in organic solutions of lecithin and bile salt: Mesoscale computer simulation

    Science.gov (United States)

    Markina, A.; Ivanov, V.; Komarov, P.; Khokhlov, A.; Tung, S.-H.

    2016-11-01

    We propose a coarse-grained model for studying the effects of adding bile salt to lecithin organosols by means of computer simulation. This model allows us to reveal the mechanisms of experimentally observed increasing of viscosity upon increasing the bile salt concentration. We show that increasing the bile salt to lecithin molar ratio induces the growth of elongated micelles of ellipsoidal and cylindrical shape due to incorporation of disklike bile salt molecules. These wormlike micelles can entangle into transient network displaying perceptible viscoelastic properties.

  16. Characterization and precipitation mechanism of α-calcium sulfate hemihydrate growing out of FGD gypsum in salt solution

    Institute of Scientific and Technical Information of China (English)

    YANG LiuChun; GUAN BaoHong; WU ZhongBiao

    2009-01-01

    Alpha-calcium sulfate hemihydrate (α-HH) has been prepared from flue gas desulfurization (FGD)gypsum with salt solution method under atmospheric pressure. X-ray diffraction (XRD), thermogra-vimetry and differential scanning calorimetry (TG-DSC), optical micrograph, X-ray photoelectron spec-troscopy (XPS), energy dispersive spectrometry (EDS), and scanning electron microscopy (SEM) have been employed to characterize the α-HH crystals, based on which the formation and growth mecha-nisms of the a-HH crystals have been discussed. The results show that FGD gypsum can be success-fully transformed into high purity α-HH in salt solution under mild conditions, and that a dissolu-tion-recrystallization route is most probably adopted by this transition. The growth of a-HH crystals in salt solution demonstrates a preferred direction along [001] and results in a bundle-of-sheets or bun-dle-of-raphide texture. The characteristics revealed in this study can help to understand and control the growth of the α-HH crystal from solution.

  17. Characterization and precipitation mechanism of α-calcium sulfate hemihydrate growing out of FGD gypsum in salt solution

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Alpha-calcium sulfate hemihydrate (α-HH) has been prepared from flue gas desulfurization (FGD) gypsum with salt solution method under atmospheric pressure. X-ray diffraction (XRD),thermogra-vimetry and differential scanning calorimetry (TG-DSC),optical micrograph,X-ray photoelectron spec-troscopy (XPS),energy dispersive spectrometry (EDS),and scanning electron microscopy (SEM) have been employed to characterize the α-HH crystals,based on which the formation and growth mecha-nisms of the α-HH crystals have been discussed. The results show that FGD gypsum can be success-fully transformed into high purity α-HH in salt solution under mild conditions,and that a dissolu-tion-recrystallization route is most probably adopted by this transition. The growth of α-HH crystals in salt solution demonstrates a preferred direction along [001] and results in a bundle-of-sheets or bun-dle-of-raphide texture. The characteristics revealed in this study can help to understand and control the growth of the α-HH crystal from solution.

  18. Electronic Tongue for Qualitative Analysis of Aqueous Solutions of Salts Using Thick-film Technology and Metal Electrodes

    Directory of Open Access Journals (Sweden)

    Juan Soto

    2006-09-01

    Full Text Available An electronic tongue for the qualitative analysis of aqueous solutions of salts hasbeen developed. The following set of electrodes was used: RuO2, Ag, and Cu in thick-filmtechnology and Au, Pb, Zn and Ni as small bars of the corresponding metal. The response ofthe designed “electronic tongue” was tested on a family of samples containing pure salt andcomplex mixtures. The electrodes were used as potentiometric un-specific sensors and thee.m.f. of each electrode in contact with a certain aqueous solution was used as input signalfor a PCA analysis. The study showed that the set of electrodes were capable to discriminatebetween aqueous solutions of salts basically by their different content in anions and cations(the anions SO42-, Cl-, PO4H2-, CO3H-, NO3- and cations Na+ and K+ were studied. In orderto better analyze the basis for the discrimination power shown by the electronic tongue, aquantitative analysis was also envisaged. A fair estimation of the concentrations of thedifferent ions in the solutions studied appeared to be possible using this electronic tonguedesign.Keywords:

  19. Ion aggregation in high salt solutions. V. Graph entropy analyses of ion aggregate structure and water hydrogen bonding network

    Science.gov (United States)

    Choi, Jun-Ho; Cho, Minhaeng

    2016-05-01

    Dissolved ions in water tend to form polydisperse ion aggregates such as ion pairs, relatively compact ion clusters, and even spatially extended ion networks with increasing salt concentration. Combining molecular dynamics simulation and graph theoretical analysis methods, we recently studied morphological structures of ion aggregates with distinctively different characteristics. They can be distinguished from each other by calculating various spectral graph theoretical properties such as eigenvalues and eigenvectors of adjacency matrices of ion aggregates and water hydrogen-bonding networks, minimum path lengths, clustering coefficients, and degree distributions. Here, we focus on percolation and graph entropic properties of ion aggregates and water hydrogen-bonding networks in high salt solutions. Ion network-forming K+ and SCN- ions at high concentrations show a percolating behavior in their aqueous solutions, but ion cluster-forming ions in NaCl solutions do not show such a transition from isolated ion aggregates to percolating ion-water mixture morphology. Despite that the ion aggregate structures are strikingly different for either cluster- or network-forming ions in high salt solutions, it is interesting that the water structures remain insensitive to the electrostatic properties, such as charge densities and polydentate properties, of dissolved ions, and morphological structures of water H-bonding networks appear to be highly robust regardless of the nature and concentration of salt. We anticipate that the present graph entropy analysis results would be of use in understanding a variety of anomalous behaviors of interfacial water around biomolecules as well as electric conductivities of high electrolyte solutions.

  20. Growth of single crystals of organic salts with large second-order optical nonlinearities by solution processes for devices

    Science.gov (United States)

    Leslie, Thomas M.

    1995-01-01

    Data obtained from the electric field induced second harmonic generation (EFISH) and Kurtz Powder Methods will be provided to MSFC for further refinement of their method. A theoretical model for predicting the second-order nonlinearities of organic salts is being worked on. Another task is the synthesis of a number of salts with various counterions. Several salts with promising SHG activities and new salts will be tested for the presence of two crystalline forms. The materials will be recrystallized from dry and wet solvents and compared for SHG efficiency. Salts that have a high SHG efficiency and no tendency to form hydrates will be documented. The synthesis of these materials are included in this report. A third task involves method to aid in the growth of large, high quality single crystals by solution processes. These crystals will be characterized for their applicability in the fabrication of devices that will be incorporated into optical computers in future programs. Single crystals of optimum quality may be obtained by crystal growth in low-gravity. The final task is the design of a temperature lowering single crystal growth apparatus for ground based work. At least one prototype will be built.

  1. Development of tropine-salt aqueous two-phase systems and removal of hydrophilic ionic liquids from aqueous solution.

    Science.gov (United States)

    Wu, Haoran; Yao, Shun; Qian, Guofei; Song, Hang

    2016-08-26

    A novel aqueous two-phase systems (ATPS) composed of a small molecule organic compound tropine and an organic or inorganic salt aqueous solution has been developed for the first time. The phase behavior of tropine-salt ATPS was systemically investigated and the phase equilibrium data were measured in different temperatures and concentrations and correlated by the Merchuk equation with satisfactory results. The detection of the conductivity and particle size proved the formation of micelle in the process of forming tropine-salt ATPS. The separation application of the ATPS was assessed with the removal of hydrophilic benzothiazolium-based ionic liquids (ILs) from aqueous solution. The result showed that ILs were effectively extracted into the top tropine-rich phase. Finally, ILs in the top tropine-rich phase were further separated by the means of adsorption-desorption with DM301 macroporous resin and ethanol. The method of novel tropine-salt ATPS combined with adsorption-desorption is demonstrated a promising alternative thought and approach for the removal or recovery of hydrophilic compounds from aqueous media and also could provide a potential application for bio-separation.

  2. Distributions of 14 elements on 60 selected absorbers from two simulant solutions (acid-dissolved sludge and alkaline supernate) for Hanford HLW Tank 102-SY

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, S.F.; Svitra, Z.V.; Bowen, S.M.

    1993-10-01

    Sixty commercially available or experimental absorber materials were evaluated for partitioning high-level radioactive waste. These absorbers included cation and anion exchange resins, inorganic exchangers, composite absorbers, and a series of liquid extractants sorbed on porous support-beads. The distributions of 14 elements onto each absorber were measured from simulated solutions that represent acid-dissolved sludge and alkaline supernate solutions from Hanford high-level waste (HLW) Tank 102-SY. The selected elements, which represent fission products (Ce, Cs, Sr, Tc, and Y); actinides (U, Pu, and Am); and matrix elements (Cr, Co, Fe, Mn, Zn, and Zr), were traced by radionuclides and assayed by gamma spectrometry. Distribution coefficients for each of the 1680 element/absorber/solution combinations were measured for dynamic contact periods of 30 min, 2 h, and 6 h to provide sorption kinetics information for the specified elements from these complex media. More than 5000 measured distribution coefficients are tabulated.

  3. Effects of Interfacial Reaction on the Radial Displacement of Oil by Alkaline Solutions Effets des réactions interfaciales sur le déplacement radial de l'huile par les solutions alcalines

    OpenAIRE

    2006-01-01

    Caustic flooding is frequently used to recover acidic oils in secondary and tertiary recovery modes. This study examines the secondary recovery of an acidic oil by alkaline solutions in a water-wet porous medium using a radial geometry. A model porous medium consisting of sintered glass beads sandwiched between two glass plates was employed to visualize the displacement process. The medium was originally saturated with the oil phase, namely paraffin oil (non-reacting system) or paraffin oil d...

  4. Marinade with alkaline solutions for the improvement of pork quality Marinados com soluções alcalinas para a melhoria da qualidade da carne suína

    OpenAIRE

    Viviane Maria Oliveira dos Santos; Fabiana Ribeiro Caldara; Leonardo de Oliveira Seno; Gelson Luis Dias Feijó; Ibiara Correia de Lima Almeida Paz; Rodrigo Garófallo Garcia; Irenilza de Alencar Nääs; Ângela Dulce Cavenaghi Altemio

    2012-01-01

    The objective of this work was to evaluate the effects of alkaline solution marinades on the characteristics of pork subjected to post-mortem pH decrease in pig muscle. The pH of carcasses was measured in a commercial slaughterhouse (n = 526), 45 min after slaughtering (pH45) and, then, the carcasses were divided into the groups with pH455.7. Ten samples of the longissimus dorsi muscles of each group were collected and distributed in an entirely randomized design, in a 2x4 factorial arrangeme...

  5. Results For The Third Quarter Calendar Year 2016 Tank 50H Salt Solution Sample

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-10-13

    In this memorandum, the chemical and radionuclide contaminant results from the Third Quarter Calendar Year 2016 (CY16) sample of Tank 50H salt solution are presented in tabulated form. The Third Quarter CY16 Tank 50H samples (a 200 mL sample obtained 6” below the surface (HTF-5-16-63) and a 1 L sample obtained 66” from the tank bottom (HTF-50-16-64)) were obtained on July 14, 2016 and received at Savannah River National Laboratory (SRNL) on the same day. Prior to obtaining the samples from Tank 50H, a single pump was run at least 4.4 hours and the samples were pulled immediately after pump shut down. The information from this characterization will be used by Defense Waste Processing Facility (DWPF) & Saltstone Facility Engineering for the transfer of aqueous waste from Tank 50H to the Saltstone Production Facility, where the waste will be treated and disposed of in the Saltstone Disposal Facility. This memorandum compares results, where applicable, to Saltstone Waste Acceptance Criteria (WAC) limits and targets.2 Data pertaining to the regulatory limits for Resource Conservation and Recovery Act (RCRA) metals will be documented at a later time per the Task Technical and Quality Assurance Plan (TTQAP) for the Tank 50H saltstone task. The chemical and radionuclide contaminant results from the characterization of the Third Quarter CY16 sampling of Tank 50H were requested by Savannah River Remediation (SRR) personnel and details of the testing are presented in the SRNL TTQAP.

  6. Results For The Third Quarter Calendar Year 2016 Tank 50H Salt Solution Sample

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-10-13

    In this memorandum, the chemical and radionuclide contaminant results from the Third Quarter Calendar Year 2016 (CY16) sample of Tank 50H salt solution are presented in tabulated form. The Third Quarter CY16 Tank 50H samples (a 200 mL sample obtained 6” below the surface (HTF-5-16-63) and a 1 L sample obtained 66” from the tank bottom (HTF-50-16-64)) were obtained on July 14, 2016 and received at Savannah River National Laboratory (SRNL) on the same day. Prior to obtaining the samples from Tank 50H, a single pump was run at least 4.4 hours, and the samples were pulled immediately after pump shut down. The information from this characterization will be used by Defense Waste Processing Facility (DWPF) & Saltstone Facility Engineering for the transfer of aqueous waste from Tank 50H to the Saltstone Production Facility, where the waste will be treated and disposed of in the Saltstone Disposal Facility. This memorandum compares results, where applicable, to Saltstone Waste Acceptance Criteria (WAC) limits and targets. Data pertaining to the regulatory limits for Resource Conservation and Recovery Act (RCRA) metals will be documented at a later time per the Task Technical and Quality Assurance Plan (TTQAP) for the Tank 50H saltstone task. The chemical and radionuclide contaminant results from the characterization of the Third Quarter CY16 sampling of Tank 50H were requested by Savannah River Remediation (SRR) personnel and details of the testing are presented in the SRNL TTQAP.

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

    Indian Academy of Sciences (India)

    Michael Rajamathi; P Vishnu Kamath

    2000-10-01

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

  8. Soft X-ray absorption spectra of aqueous salt solutions with highly charged cations in liquid microjets

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Craig P.; Uejio, Janel S.; Duffin, Andrew M.; Drisdell, Walter S.; Smith, Jared D.; Saykally, Richard J.

    2010-03-11

    X-ray absorption spectra of 1M aqueous solutions of indium (III) chloride, yttrium (III) bromide, lanthanum (III) chloride, tin (IV) chloride and chromium (III) chloride have been measured at the oxygen K-edge. Relatively minor changes are observed in the spectra compared to that of pure water. SnCl{sub 4} and CrCl{sub 3} exhibit a new onset feature which is attributed to formation of hydroxide or other complex molecules in the solution. At higher energy, only relatively minor, but salt-specific changes in the spectra occur. The small magnitude of the observed spectral changes is ascribed to offsetting perturbations by the cations and anions.

  9. [Aqueous and salt solutions of quinine of low concentrations: self-organization, physicochemical properties and actions on the electrical characteristics of neurons].

    Science.gov (United States)

    Murtazina, L I; Ryzhkina, I S; Mishina, O A; Andrianov, V V; Bogodvid, T Kh; Gaĭnutdinov, Kh L; Muranova, L N; Konovalov, A I

    2014-01-01

    Self-organization, the physicochemical properties of aqueous and salt solutions of quinine and the effects of salt quinine solutions in a wide range of concentrations (1 x 10(-22) - 1 x 10(-3) M) on the electrical characteristics of the edible snail's identified neurons were studied. Similar non-monotonic concentration dependencies of physicochemical properties of aqueous and salt quinine solutions at low concentrations are obtained. This allows of predicting the occurrence of biological effects at low concentrations of quinine solutions. Intrinsic (within 5% of the interval) changes in membrane potential, the amplitude and duration of the neuron action potential under the influence of quinine salt solutions at concentrations of quinine of 1 x 10(-20), 1 x 10(-18), 1 x 10(-10) M are found. For these concentrations the extreme values of specific conductivity and pH are shown.

  10. Molecular Thermodynamic Model for Polyelectrolyte Solutions with Added Salts%含盐聚电解质溶液的分子热力学模型

    Institute of Scientific and Technical Information of China (English)

    张波; 蔡钧; 刘洪来; 胡英

    2002-01-01

    A molecular thermodynamic model of polyelectrolyte developed previously was extended to polyelectrolyte solutions with added salts. Thermodynamic properties, such as activity coefficients of polyelectrolytes or added salts and osmotic coefficients of solvent, of a number of aqueous mixtures of polyelectrolytes and salts are analyzed with the proposed model. Successful correlation is obtained in the range of moderate or higher polyion concentration. For the same sample, thermodynamic properties of polyelectrolytes with and without simple electrolytes can be predicted mutually using parameters from regression data.

  11. Chloride-inducible transient apoplastic alkalinizations induce stomata closure by controlling abscisic acid distribution between leaf apoplast and guard cells in salt-stressed Vicia faba.

    Science.gov (United States)

    Geilfus, Christoph-Martin; Mithöfer, Axel; Ludwig-Müller, Jutta; Zörb, Christian; Muehling, Karl H

    2015-11-01

    Chloride stress causes the leaf apoplast transiently to alkalize, an event that is presumed to contribute to the ability of plants to adapt to saline conditions. However, the initiation of coordinated processes downstream of the alkalinization is unknown. We hypothesize that chloride-inducible pH dynamics are a key chemical feature modulating the compartmental distribution of abscisic acid (ABA) and, as a consequence, affecting stomata aperture. Apoplastic pH and stomata aperture dynamics in intact Vicia faba leaves were monitored by microscopy-based ratio imaging and porometric measurements of stomatal conductance. ABA concentrations in leaf apoplast and guard cells were compared with pH dynamics by gas-chromatography-mass-spectrometry (GC-MS) and liquid-chromatography-tandem-mass spectrometry (LC-MS/MS). Results demonstrate that, upon chloride addition to roots, an alkalizing factor that initiates the pH dynamic propagates from root to leaf in a way similar to xylem-distributed water. In leaves, it induces a systemic transient apoplastic alkalinization that causes apoplastic ABA concentration to increase, followed by an elevation of endogenous guard cell ABA. We conclude that the transient alkalinization, which is a remote effect of chloride stress, modulates the compartmental distribution of ABA between the leaf apoplast and the guard cells and, in this way, is instrumental in inducing stomata closure during the beginning of salinity.

  12. Plants increase arsenic in solution but decrease the non-specifically bound fraction in the rhizosphere of an alkaline, naturally rich soil.

    Science.gov (United States)

    Obeidy, Carole; Bravin, Matthieu N; Bouchardon, Jean-Luc; Conord, Cyrille; Moutte, Jacques; Guy, Bernard; Faure, Olivier

    2016-04-01

    We aimed at determining the major physical-chemical processes that drive arsenic (As) dynamic in the rhizosphere of four species (Holcus lanatus, Dittrichia viscosa, Lotus corniculatus, Plantago lanceolata) tested for phytostabilization. Experiments were performed with an alkaline soil naturally rich in As. Composition of the soil solution of planted and unplanted pots was monitored every 15 days for 90 days, with a focus on the evolution of As concentrations in solution and in the non-specifically bound (i.e. easily exchangeable) fraction. The four species similarly increased As concentration in solution, but decreased As concentration in the non-specifically bound fraction. The major part (60%) of As desorbed from the non-specifically bound fraction in planted pots was likely redistributed on the less available fractions of As on the solid phase. A second part (35%) of desorbed As was taken up by plants. The minor part (5%) of desorbed As supplied As increase in solution. To conclude, plants induced a substantial redistribution of As on the less available fractions in the rhizosphere, as expected in phytostabilization strategies. Plants however concomitantly increased As concentration in the rhizosphere solution which may contribute to As transfer through plant uptake and leaching.

  13. On the appearance of vorticity and gradient shear bands in wormlike micellar solutions of different CPCl/salt systems

    Energy Technology Data Exchange (ETDEWEB)

    Mütze, Annekathrin, E-mail: muetzea@ethz.ch; Heunemann, Peggy; Fischer, Peter [ETH Zürich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 9, 8092 Zürich (Switzerland)

    2014-11-01

    Wormlike micellar salt/surfactant solutions (X-salicylate, cetylpyridinium chloride) are studied with respect to the applied shear stress, concentration, temperature, and composition of the counterions (X = lithium, sodium, potassium, magnesium, and calcium) of the salicylate salt solute to determine vorticity and gradient shear bands. A combination of rheological measurements, laser technique, video analysis, and rheo-small-angle neutron scattering allow for a detailed exploration of number and types of shear bands. Typical flow curves of the solutions show Newtonian, shear-thinning, and shear-thickening flow behavior. In the shear-thickening regime, the solutions show vorticity and gradient shear bands simultaneously, in which vorticity shear bands dominate the visual effect, while gradient shear bands always coexist and predominate the rheological response. It is shown that gradient shear bands change their phases (turbid, clear) with the same frequency as the shear rate oscillates, whereas vorticity shear bands change their phases with half the frequency of the shear rate. Furthermore, we show that with increasing molecular mass of the counterions the number of gradient shear bands increases, while the number of vorticity shear bands remains constant. The variation of temperature, shear stress, concentration, and counterions results in a predictable change in the rheological behavior and therefore allows adjustment of the number of vorticity shear bands in the shear band regime.

  14. Bathing in a magnesium-rich Dead Sea salt solution improves skin barrier function, enhances skin hydration, and reduces inflammation in atopic dry skin.

    Science.gov (United States)

    Proksch, Ehrhardt; Nissen, Hans-Peter; Bremgartner, Markus; Urquhart, Colin

    2005-02-01

    Magnesium salts, the prevalent minerals in Dead Sea water, are known to exhibit favorable effects in inflammatory diseases. We examined the efficacy of bathing atopic subjects in a salt rich in magnesium chloride from deep layers of the Dead Sea (Mavena(R) Dermaline Mg(46) Dead Sea salt, Mavena AG, Belp, Switzerland). Volunteers with atopic dry skin submerged one forearm for 15 min in a bath solution containing 5% Dead Sea salt. The second arm was submerged in tap water as control. Before the study and at weeks 1-6, transepidermal water loss (TEWL), skin hydration, skin roughness, and skin redness were determined. We found one subgroup with a normal and one subgroup with an elevated TEWL before the study. Bathing in the Dead Sea salt solution significantly improved skin barrier function compared with the tap water-treated control forearm in the subgroup with elevated basal TEWL. Skin hydration was enhanced on the forearm treated with the Dead Sea salt in each group, which means the treatment moisturized the skin. Skin roughness and redness of the skin as a marker for inflammation were significantly reduced after bathing in the salt solution. This demonstrates that bathing in the salt solution was well tolerated, improved skin barrier function, enhanced stratum corneum hydration, and reduced skin roughness and inflammation. We suggest that the favorable effects of bathing in the Dead Sea salt solution are most likely related to the high magnesium content. Magnesium salts are known to bind water, influence epidermal proliferation and differentiation, and enhance permeability barrier repair.

  15. Salting the landscapes in Transbaikalia: natural and technogenic factors

    Science.gov (United States)

    Peryazeva, E. G.; Plyusnin, A. M.; Chinavlev, A. M.

    2010-05-01

    Salting the soils, surface and subsurface waters is widespread in Transbaikalia. Hearths of salting occur within intermountain depressions of the Mesozoic and Cenozoic age both in the steppe arid and forest humid landscapes. Total water mineralization reaches 80 g/dm3 in lakes and 4-5 g/dm3 in subsurface waters. The waters belong to hydrocarbonate sodium and sulfate sodium types by chemical composition. The soda type of waters is widely spread through the whole area. Sulfate waters are found in several hearths of salting. Deposition of salts takes place in some lakes. Mirabilite and soda depositions are most commonly observed in muds of salt lakes. Deposition of salts occurs both as a result of evaporative concentrating and during freezing out the solvent. In the winter period, efflorescences of salts, where decawater soda is main mineral, are observed on ice surface. Solonchaks are spread in areas of shallow ground waters (1-2m). Soil salting is most intense in the lower parts of depressions, where surface of ground waters is at depth 0.5-1.0m. In soil cover of solonchaks, salt horizon is of various thicknesses, and it has various morphological forms of occurrence, i.e. as thick deposits of salts on soil surface and salting the surficial horizons. The soil has low alkaline reaction of medium and is characterized by high content of exchangeable bases with significant content of exchangeable sodium in the absorbing complex. Total amount of salts varies from 0.7 to 1.3%. Their maximal quantity (3.1%) is confined to the surficial layer. Sulfate-sodium type of salting is noted in the solonchak upper horizons and sulfate-magnesium-calcium one in the lower ones (Ubugunov et al, 2009). Formation of salting hearths is associated with natural and technogenic conditions. The Mesozoic depressions of Transbaikalia are characterized by intense volcanism. Covers of alkaline and moderately alkaline basalts that are enriched in potassium, sodium, carbon dioxide, fluorine, chlorine

  16. Urothelial injury to the rabbit bladder from various alkaline and acidic solutions used to dissolve kidney stones.

    Science.gov (United States)

    Reckler, J; Rodman, J S; Jacobs, D; Rotterdam, H; Marion, D; Vaughan, E D

    1986-07-01

    Different irrigating solutions are used clinically to dissolve uric acid, cystine and struvite stones. These studies were undertaken to assess the toxicity to the rabbit bladder epithelium of several commonly used formulations. Test solutions were infused antegrade through a left ureterotomy overnight. Bladders were removed and routine histological sections made. A pH 7.6 solution of NaHCO3 appeared harmless. The same solution with two per cent acetylcysteine produced slight injury. All pH 4 solutions caused significant damage to the urothelium. Hemiacidrin, which contains magnesium, produced less damage than did other pH 4 solutions without that cation. Our data tend to support Suby's conclusions that addition of magnesium reduces urothelial injury even though the presence of magnesium will slow dissolution of struvite.

  17. Influence of beryllium cations on the electrochemical oxidation of methanol on stepped platinum surfaces in alkaline solution

    Science.gov (United States)

    García, Gonzalo; Stoffelsma, Chantal; Rodriguez, Paramaconi; Koper, Marc T. M.

    2015-01-01

    The role of beryllium on the oxidation of methanol on Pt stepped surfaces (Pt[(n-1) (111)x(110)]) orientation-Pt(553) with n = 5, Pt(554) n = 10, Pt(151514) n = 30), Pt(111) and Pt(110) single crystals in alkaline media was studied by cyclic voltammetry and Fourier transform infrared spectroscopy (FTIRS). The results suggest that under the conditions of the experiment, the methanol oxidation reaction follows a direct pathway with formaldehyde and formate as reaction intermediates. The combination of OHads and beryllium blocks the adsorption and oxidation of methanol on Pt(111), but appears to promote the complete oxidation of methanol to carbon dioxide/carbonate on Pt(110).

  18. Counterion influence on the vibrational wavenumbers in ternary and quaternary metal hydride salts, A2MH6 (A = alkali metal, alkaline earth, and lanthanides; M = Ir, Fe, Ru, Os, Pt, Mn).

    Science.gov (United States)

    Gilson, Denis F R; Moyer, Ralph O

    2012-02-06

    The wavenumbers of the ν(3) metal-hydrogen stretching mode (T(1u)) in the IR spectra of both ternary and quaternary hexahydrido salts of transition metals from groups 7 to 10 ([Mn(I)H(6)](5-), [Fe(II)H(6)](4-), [Ru(II)H(6)](4-), [Os(II)H(6)](4-), [Ir(III)H(6)](3-), and [Pt(IV)H(6)](2-)) depend linearly upon the ionization energies of the counterions (alkali metal, alkaline earth, and lanthanide) with a separate line for each metal. This relationship provides quantitative support for the charge-transfer mechanism for explaining the stabilities of these compounds.

  19. Glyoxal and methylglyoxal Setschenow salting constants in sulfate, nitrate, and chloride solutions

    DEFF Research Database (Denmark)

    Waxman, Eleanor M.; Elm, Jonas; Kurtén, Theo;

    2015-01-01

    . We have measured KS of glyoxal and methylglyoxal for the atmospherically relevant salts (NH4)2SO4, NH4NO3, NaNO3, and NaCl and find that glyoxal consistently "salts-in" (KS of -0.16, -0.06, -0.065, -0.1 molality(-1), respectively) while methylglyoxal "salts-out" (KS of +0.16, +0.075, +0.02, +0.......06 molality(-1)). We show that KS values for different salts are additive and present an equation for use in atmospheric models. Additionally, we have performed a series of quantum chemical calculations to determine the interactions between glyoxal/methylglyoxal monohydrate with Cl(-), NO3(-), SO4(2-), Na......(+), and NH4(+) and find Gibbs free energies of water displacement of -10.9, -22.0, -22.9, 2.09, and 1.2 kJ/mol for glyoxal monohydrate and -3.1, -10.3, -7.91, 6.11, and 1.6 kJ/mol for methylglyoxal monohydrate with uncertainties of 8 kJ/mol. The quantum chemical calculations support that SO4(2-), NO3...

  20. Preparation of glass carbon electrode modified with nanocrystalline nickel-decorated carbon nanotubes and electrocatalytic oxidation of methanol in alkaline solution

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Nanocrystalline nickel with an average diameter of about 16 nm and a face-centered cubic (fcc)structure was uniformly attached to the surface of carbon nanotubes (CNT) by wet chemistry.The sample was characterized by X-ray powder diffraction and transmission electron microscopy (TEM).A glass carbon electrode modified with nickel-modified multi-wall carbon nanotubes (MWCNTs-Ni/GCE) was prepared.The electrochemical behavior of the MWCNTs-Ni/GCE and the electrocatalytic oxidation of methanol at the MWCNTsNi/GCE were investigated by cyclic voltammetry in 1.0 mol/L NaOH solution.The cyclic voltammograms showed that the electron transfer between β-Ni(OH)2 and β-NiOOH is mainly a diffusion-controlled quasireversible process,and that the electrode has high catalytic activity for the electrooxidation of methanol in alkaline medium,revealing its potential application in alkaline rechargeable batteries and fuel cells.

  1. On the vibrational behaviour of cyanide adsorbed at Pt(1 1 1) and Pt(1 0 0) surfaces in alkaline solutions

    Science.gov (United States)

    Huerta, F.; Montilla, F.; Morallón, E.; Vázquez, J. L.

    2006-03-01

    This communication deals with the vibrational behaviour of cyanide adlayers formed on Pt(1 1 1) and Pt(1 0 0) surfaces in the electrochemical environment. In situ FTIR spectroscopy can be employed to follow the potential dependence of the C-N stretching frequency in acidic electrolytes with quite a low uncertainty. Owing to the stability of the cyanide adlayer in alkaline solutions, experiments performed in NaOH medium are usually perturbed by the significant overlapping of the reference and the sample FTIR spectra. Deconvolution of the spectra was carried out assuming a Lorentz oscillator. The procedure allowed to confirm that two potential regions with different band centre frequency tuning coexist for Pt(1 1 1)-CN in perchloric acid medium. Conversely, in the alkaline electrolyte a single tuning rate for the band position was found for both surfaces studied. The lack of reorientation of the C-N molecular axis together with the occurrence of a certain screening effect of negatively charged hydroxyl anions on the electric field at the interface could be at the origin of the different behaviour displayed in both electrolytic media.

  2. Amino-functionalized alkaline clay with cationic star-shaped polymer as adsorbents for removal of Cr(VI) in aqueous solution

    Science.gov (United States)

    Pan, Yuanfeng; Cai, Pingxiong; Farmahini-Farahani, Madjid; Li, Yiduo; Hou, Xiaobang; Xiao, Huining

    2016-11-01

    Pentaerythritol (PER) was esterified with 2-bromoisobutyryl bromide to synthesize a four-arm initiator 4Br-PER for atom transfer radical polymerization (ATRP). Star-shaped copolymers (P(AM-co-DMAEMA)4, CSP) were prepared via ATRP using dimethyl aminoethyl methacrylate (DMAEMA) and acrylamide (AM) as comonomers, while Br-PER and CuBr/2,2‧-bipyridine (BPY) as the initiator and the catalyst, respectively. The resulting four-arm initiator and star-shaped polymer (CSP) were characterized with FT-IR, 1H NMR and Ubbelohde viscometry. Alkaline clay (AC) was immobilized with CSPs to yield amino groups, and the cationic star polymer-immobilized alkaline clay (CSP-AC) was applied to remove Cr(VI) from the aqueous solution in batch experiments. Various influencing factors, including pH, contact time and immobilization amount of CSP on adsorption capacity of CSP-AC for Cr(VI) were also investigated. The results demonstrated that Cr(VI) adsorption was highly pH dependent. The optimized pH value was 4.0. The adsorption isotherms of the adsorbent fit the Langmuir model well, with the maximum adsorption capacity of 137.9 mg/g at 30 °C. The material should be a promising adsorbent for Cr(VI) removal, with the advantages of high adsorption capacity.

  3. Comparative Study of the Preparation of Reducing Sugars Hydrolyzed from High-Lignin Lignocellulose Pretreated with Ionic Liquid, Alkaline Solution and Their Combination

    Directory of Open Access Journals (Sweden)

    Hanny F. Sangian

    2015-05-01

    Full Text Available The ionicliquid [MMIM][DMP] was synthesized from the reactants methyl imidazole [MIM] and trimethylphosphate [TMP] and verified using 1HNMR and FTIR. Coconut coir dust was pretreated with a 1% alkaline solution.Its crystalline structure increased significantly due to the dissolution of lignin and hemicelluloses under alkaline conditions, exposing the cellulose. After NaOH and IL were employed, the XRD showed that peak (002 decreased significantly and peak (101 almost vanished. This significant decrease in crystallinity was related to the alteration of the substrate from the cellulose I structure to the cellulose II structure. The pretreated substrates were hydrolyzed to convert them to reducing sugars by pure cellulase and xylanase,and the reaction was conducted at 60°C, pH 3, for 12 or 48 hours. The yields of sugar hydrolyzed from untreated and NaOH-pretreated substrates were 0.07 and 0.12 g sugar/g lignocellulose, respectively. Pretreatment with IL or the combination of NaOH+IL resulted in yields of reducing sugars of 0.11 and 0.13 g/g, respectively. These findings showed that IL pretreatment of the high-lignin lignocellulose is a new prospect for the economical manufacture of reducing sugars and bioethanol in the coming years.

  4. 等渗透势干旱、盐、碱胁迫下5个枣品种及酸枣的生物学响应与抗逆性%Biological responses and resistances of five cultivars of Chinese jujube and sour date under iso-osmotic drought, salt and alkaline stresses

    Institute of Scientific and Technical Information of China (English)

    徐呈祥

    2012-01-01

    differences were evaluated. By taking 2-year old grafted plants of ' Jinsixiaozao' and other four Chinese jujuba cultivars and sour date seedlings as the tested materials, under osmotic potential of -0.30 MPa and -1.15 MPa, irrigated with l/2Hoagland nutrient solution, and taking without added PEG-6000 and NaCl and NaHCO3 as the control, the drought (simulated with PEG-6000), salt and alkaline stresses were conducted. The results show that the biomass was more acurate than the growth index to reflect the responses of Chinese jujuba and sour date to the stresses, the differences among the indexes were significant; the plant height and crown diameter were hardly differences to same stress, however, length and base diamete of leading-head limb were rather sensitive to stress type and its osmotic potention; leaf biomass and abcisic limb biomass were much sensitive to these stresses, next was plant biomass, stem biomass and root biomass were Least sensitive to these stresses. The differences of resistances to these stresses of the 5 Chinese jujube cultivars and sour date were significant alluvaled with 3 sensitive indexes, leaf biomass-t- deciduate branches biomass, plant biomas and their ratio (leaf biomass+ deciduatc branches biomass)/plant biomas, in which Daguanzao and Lizao were the most to drought stress, Daguazao was the most to salt tolerance, sour date and Daguazao were the most to alkaline tolerance. Meanwhile, responses of each of 5 Chinese jujuba cultivars and sour date to these stresses were different; Daguazao is a good cultivar with super tolerances to dropught, salt and alkaline stresses; while Dongzao is a cultivar of neither drought resistance nor salt and alkaline tolerances, compartively, its salt tolerance is stronger than drought resistance or alkaline tolerance. These results indicate that resistance defferences of Chinese jujuba cultivars to abiotic stresses were rather large in fact, and palying more attention to eco-physiological characterestics of

  5. Correlation between UV-VIS spectra and the structure of Cu(II) complexes with hydrogenated dextran in alkaline solutions

    OpenAIRE

    Nikolić Goran S.; Cakić Milorad D.; Mitić Žarko J.; Nikolić Ružica S.; Ilić Ljubomir A.

    2005-01-01

    UV-VIS spectrophotometric investigations of Cu(II) complexes with hydroge-nated dextran showed that the complexation of Cu(II)-ions began at pH > 7. The formation of Cu(II) complexes with dextran monomer units was observed at pH 7-12. With further increase in solution pH > 12, the Cu(II)-dextran complex decomposed to Cu(OH)42~-ions and dextran. With increasing solution pH the absorption maximum of complex solutions increased and shifted to shorter wavelength (hypsochromic shift) compare...

  6. Facile synthesis of nitrogen-doped carbon nanotubes encapsulating nickel cobalt alloys 3D networks for oxygen evolution reaction in an alkaline solution

    Science.gov (United States)

    Yu, Jie; Zhong, Yijun; Zhou, Wei; Shao, Zongping

    2017-01-01

    Efficient oxygen evolution reaction (OER) catalysts are required to facilitate the large-scale exploitation of renewable energy resources and applications in electrochemical energy conversion technologies. Here, we show that metal alloy-based hybrids can provide higher electrocatalytic activity than their individual metal-based hybrids. In particular, NiCo alloys encapsulated within nitrogen-doped carbon nanotubes (NiCo@NCNTs) showed higher OER activities in an alkaline solution than the individual metal hybrids (Ni@NCNTs and Co@NCNTs), highlighting a synergy between the Ni and Co components. NiCo@NCNTs pyrolyzed at 800 °C displayed an overpotential of ∼41 mV at a current density of 10 mA cm-2 and were more stable than IrO2 during 1000-cycle accelerated durability testing at a scan rate of 100 mV s-1.

  7. Estimation on gas generation and corrosion rates of carbon steel, stainless steel and zircaloy in alkaline solutions under low oxygen condition

    Energy Technology Data Exchange (ETDEWEB)

    Mihara, Morihiro; Honda, Akira [Japan Nuclear Cycle Development Inst., Tokai Works, Tokai, Ibaraki (Japan); Nishimura, Tsutomu; Wada, Ryutaro [Kobe Steel Ltd., Engineering Company, Energy and Nuclear System Center, Osaka (Japan)

    2002-06-01

    Hydrogen gas generated by corrosion of metals in TRU waste repository may degrade the function of the engineered barrier system for nuclide migration. Therefore, estimation of gas generation rates of metals under the repository condition is important. In this study, we obtained gas generation rates of carbon steel, stainless steel and zircaloy in alkaline solutions under low oxygen conditions and evaluated the corrosion rates based on these data in order to compare with the published data. The magnitude of corrosion rates of carbon steel, stainless steel and zircaloy were 10{sup -1} {mu}m/y, 10{sup -2} {mu}m/y and 10{sup -3} {mu}m/y, respectively. These values agreed with the published corrosion rates from gas generation rates by others. (author)

  8. NiP₂ nanosheet arrays supported on carbon cloth: an efficient 3D hydrogen evolution cathode in both acidic and alkaline solutions.

    Science.gov (United States)

    Jiang, Ping; Liu, Qian; Sun, Xuping

    2014-11-21

    Designing efficient and stable hydrogen evolution catalysts made from earth-abundant elements is essential to the development of solar-driven water-splitting devices. In this communication, we develop a two-step strategy for constructing NiP2 nanosheet arrays on carbon cloth (NiP2 NS/CC). As a novel 3D hydrogen evolution cathode, the NiP2 NS/CC electrode is highly active in acidic solutions and needs an overpotential of 75 and 204 mV to achieve current densities of 10 and 100 mA cm(-2), respectively, and it preserves its catalytic activity for at least 57 h. Moreover, it also operates efficiently under alkaline conditions.

  9. The oxidation of chromium(III) by hydroxyl radical in alkaline solution. A stopped-flow and pre-mix pulse radiolysis study

    DEFF Research Database (Denmark)

    Zhao, Zhongwei; Rush, J.D.; Holcman, J.

    1995-01-01

    The pK(a) for the equilibrium Cr(III)(H2O)3(OH)3(OH)3 reversible Cr(III)(H2O)2(OH)4- + H+ was determined to be 12.8 at 25-degrees-C. The dimerization of the two monomeric forms was studied in alkaline solutions using the stopped-flow method: k2[Cr(III)(H2O)3(OH)3 + Cr(III)(H2O)3(OH)3] = (2.5 +/- ......(VI)-(O-Cr(III))n]. Furthermore, a second-order reaction between two Cr(IV) monomers to yield a species which may be either a (Cr)2IV,IV or a (Cr)2III,V mixed-valence dimer was observed. The corresponding spectra in both the UV and visible range were determined....

  10. Catalytic Oxidative Conversion from Naphthol to 2-Hydroxy-1, 4-naphthoquinone over Iron Porphyrin Catalysts by Molecular Oxygen in an Alkaline 2-Propanol Solution

    Institute of Scientific and Technical Information of China (English)

    YANG Ke-er; TONG Shan-ling; YAN Yan; KANG En-hua; XIAO Feng-shou; LI Qing; CHANG Xin; FANG Chi-guang

    2005-01-01

    In an alkaline 2-propanol solution with 5,10,15,20-tetra(4-methoxyl phenyl) porphyrin iron chloride(TOMPPFeCl) as a catalyst and oxygen as a cheap green oxidant, 2-naphthol was conversed to 2-hydroxy-1,4-naphthoquinone(HNQ) with a yield of 62.17% and a selectivity of 100%, and the conversion number of TMOPPFeCl catalyst was 8.32/min. The catalytic oxidation products were characterized by means of UV-Vis, IR, GC-MS, 1H NMR and melting point determination. In this catalytic oxidation, the catalytic activity of TMOPPFeCl was researched in detail and the reacting conditions were optimized. A possible reaction mechanism is summarized based on in situ EPR determination.

  11. Alkaline treatment of timber sawdust: A straightforward route toward effective low-cost adsorbent for the enhanced removal of basic dyes from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Yamina Djilali

    2016-09-01

    Full Text Available The present study assesses the ability of two low-cost adsorbents – timber sawdust (TS–OH and its alkaline treated analog (TS–ONa – to remove two basic dyes, namely, Methylene Blue and Methyl Green, from aqueous solutions. The presence of new functional groups on the surface of TS–ONa resulted in a dramatic increase of surface polarity and the density of sorption sites, thereby improving the sorption efficiency of the cationic dyes. The results obtained from the sorption characteristics have revealed that the sorption process for TS–ONa was uniform and rapid. The adsorption of cationic dyes reached equilibrium within the first 10 min of contact time and the treated material acts efficiently in a wide pH range of dye solutions. The extent of adsorption was measured through equilibrium sorption isotherms and analyzed using the Langmuir model. The monolayer saturation capacities for Methylene Blue are 694.44 and 1928.31 mg g−1 and for Methyl Green are 892.86 and 1821.33 mg g−1 for TS–OH and TS–ONa, respectively. Therefore, the chemically treated sawdust proved two- to threefold higher adsorption capacities of these dyes than those of the untreated analog. The exothermic nature of adsorption is demonstrated by a decrease of adsorption capacity with increasing temperature, and the negative value of free energy change indicated the spontaneity of adsorption. Desorption experiments with 1 M aqueous NaCl put into evidence that cationic dyes were completely desorbed from the matrices and the reusability of the TS–ONa matrix after three repeated cycles led to just a slight attenuation in its performance. These results show that alkaline treatment of a low value by-product of the timber industry leads to a powerful and efficient low-cost adsorbent, which may be used for the treatment of colored wastewaters.

  12. LCMS-QTOF Determination of Lentinan-Like β-D-Glucan Content Isolated by Hot Water and Alkaline Solution from Tiger’s Milk Mushroom, Termite Mushroom, and Selected Local Market Mushrooms

    OpenAIRE

    Nor Azreen Mohd Jamil; Norasfaliza Rahmad; Noraswati Mohd Nor Rashid; Mohd Hafis Yuswan Mohd Yusoff; Nur Syahidah Shaharuddin; Norihan Mohd Saleh

    2013-01-01

    Lentinan, 1152 Dalton β-D-glucan found in Shiitake Mushroom (Lentinus edodes), has been claimed to have anticancer and immunomodulatory activity. Several extraction methods have been used by researchers to isolate Lentinan including hot water and alkaline solution (1.25 M NaOH). In this study, hot water and alkaline solution (1.25 M NaOH) were used to extract the Lentinan-like β-D-glucan (1151 Dalton) from Tiger’s Milk Mushroom, Termite Mushroom, and selected local market mushrooms. The isola...

  13. Bupivacaine salts of diflunisal and other aromatic hydroxycarboxylic acids: aqueous solubility and release characteristics from solutions and suspensions using a rotating dialysis cell model.

    Science.gov (United States)

    Østergaard, Jesper; Larsen, Susan W; Parshad, Henrik; Larsen, Claus

    2005-11-01

    In the search for poorly soluble bupivacaine salts potentially enabling prolonged postoperative pain relief after local joint administration in the form of suspensions the solubility of bupivacaine salts of diflunisal and other aromatic hydroxycarboxylic acids were investigated together with the release characteristics of selected 1:1 salts from solutions and suspensions using a rotating dialysis cell model. The poorest soluble bupivacaine salts were obtained from the aromatic ortho-hydroxycarboxylic acids diflunisal, 5-iodosalicylic acid, and salicylic acid (aqueous solubilities: 0.6-1.9 mM at 37 degrees C). Diffusant appearance rates in the acceptor phase upon instillation of solutions of various salts in the donor cell applied to first-order kinetics. Calculated permeability coefficients for bupivacaine and the counterions diflunisal, 5-iodosalicylic acid, and mandelic acid were found to be correlated with the molecular size of the diffusants. Release experiments at physiological pH involving suspensions of the bupivacaine-diflunisal salt revealed that at each sampling point the diflunisal concentration exceeded that of bupivacaine in the acceptor phase. However, after an initial lag period, a steady state situation was attained resulting in equal and constant fluxes of the two diffusants controlled by the permeability coefficients in combination with the solubility product of the salt. Due to the fact that the saturation solubility of the bupivacaine-salicylic acid salt in water exceeded that of bupivacaine at pH 7.4, suspensions of the latter salt were unable to provide simultaneous release of the cationic and anionic species at pH 7.4. The release profiles were characterised by a rapid release of salicylate accompanied by a much slower appearance of bupivacaine in the acceptor phase caused by precipitation of bupivacaine base from the solution upon dissolution of the salt in the donor cell.

  14. Electrodeposition, characterization and long term stability of NiW and NiWZn coatings on copper substrate in alkaline solution

    Science.gov (United States)

    Sürme, Yavuz; Gürten, A. Ali; Kayakırılmaz, Kadriye

    2013-07-01

    This paper describes the electrodeposition of Ni, NiW and NiWZn coatings onto copper surfaces from electrolyte solutions containing Na3C6H5O7, Na2WO4, NiSO4 and ZnSO4. The electrocatalytic effects of electrodeposited coatings were investigated for hydrogen evolution reactions in 1 M NaOH solution. Surface characterization studies were carried out by energy dispersive X-ray spectroscopy, scanning electron microscopy, atomic force microscopy and cross-section analysis. The effect of operating conditions on the chemical composition, microstructure and electrocatalytic properties of Ni-W coatings was studied. The Zn ions were used to improve the active surface area and catalytic activity of the electrodeposited surface. The electrocatalytic activity of NiW and NiWZn coated electrodes for the hydrogen evolution reaction in alkaline solution was compared with that of an electrodeposited Ni electrode and copper substrate by using cathodic polarization curves and electrochemical impedance spectroscopy techniques over 96 h of electrolysis. The results proved that the NiWZn coated electrode showed better electrocatalytic activity and durability than bare Cu, Ni and NiW coatings.

  15. Study of the electrochemical oxidation and reduction of C.I. Reactive Orange 4 in sodium sulphate alkaline solutions.

    Science.gov (United States)

    del Río, A I; Molina, J; Bonastre, J; Cases, F

    2009-12-15

    Synthetic solutions of hydrolysed C.I. Reactive Orange 4, a monoazo textile dye commercially named Procion Orange MX-2R (PMX2R) and colour index number C.I. 18260, was exposed to electrochemical treatment under galvanostatic conditions and Na2SO4 as electrolyte. The influence of the electrochemical process as well as the applied current density was evaluated. Ti/SnO2-Sb-Pt and stainless steel electrodes were used as anode and cathode, respectively, and the intermediates generated on the cathode during electrochemical reduction were investigated. Aliquots of the solutions treated were analysed by UV-visible and FTIR-ATR spectroscopy confirming the presence of aromatic structures in solution when an electro-reduction was carried out. Electro-oxidation degraded both the azo group and aromatic structures. HPLC measures revealed that all processes followed pseudo-first order kinetics and decolourisation rates showed a considerable dependency on the applied current density. CV experiments and XPS analyses were carried out to study the behaviour of both PMX2R and intermediates and to analyse the state of the cathode after the electrochemical reduction, respectively. It was observed the presence of a main intermediate in solution after an electrochemical reduction whose chemical structure is similar to 2-amino-1,5-naphthalenedisulphonic acid. Moreover, the analysis of the cathode surface after electrochemical reduction reveals the presence of a coating layer with organic nature.

  16. Correlation between UV-VIS spectra and the structure of Cu(II complexes with hydrogenated dextran in alkaline solutions

    Directory of Open Access Journals (Sweden)

    Nikolić Goran S.

    2005-01-01

    Full Text Available UV-VIS spectrophotometric investigations of Cu(II complexes with hydroge-nated dextran showed that the complexation of Cu(II-ions began at pH > 7. The formation of Cu(II complexes with dextran monomer units was observed at pH 7-12. With further increase in solution pH > 12, the Cu(II-dextran complex decomposed to Cu(OH42~-ions and dextran. With increasing solution pH the absorption maximum of complex solutions increased and shifted to shorter wavelength (hypsochromic shift compared with uncomplexed Cu(II. The UV spectra displayed bathochromic shifts. The changes of UV-VIS spectra with increasing in solution pH confirmed the formation of different kinds of complex species. The correlation between the results of UV-VIS spectrophotometry and the central metal ionligand coordination predicted that the copper binding within the complex depended on the pH and participation H2O molecules. Dextran complexes with Cu(II were formed by the displacement of water molecules from the coordination sphere of copper by OH groups. The analysis indicated that the Cu(II center was coordinated to two glucopyranose units of dextran. The spectrophotometric parameters of the investigated complexes were characteristic of a Cu(II-ion in a square-planar or tetragon ally distorted octahedral coordination.

  17. Non-trivial solution chemistry between amido-pyridylcalix[4]arenes and some metal salts

    OpenAIRE

    Colleran, John; Creaven, Bernadette; Donlon, Denise; McGinley, John

    2010-01-01

    Mercury ion complexation reactions were carried out between 3 and various mercury(II) salts. 1H NMR studies showed that the role of solvent, the anion chosen and the initial reaction conditions were critical and that the formation of a “simple” mercury(II) complex was non-trivial. The mercury(II) ion can cause either (i) the formation of an ion-pair system, which have a characteristic doubling of all signals in the 1H NMR spectrum, (ii) a cleavage reaction to occur resulting in the reformatio...

  18. Simulation of NaCl and KCl mass transfer during salting of Prato cheese in brine with agitation: a numerical solution

    Directory of Open Access Journals (Sweden)

    E. Bona

    2007-09-01

    Full Text Available The association of dietary NaCl with arterial hypertension has led to a reduction in the levels of this salt in cheeses. For salting, KCl has been used as a partial substitute for NaCl, which cannot be completely substituted without affecting product acceptability. In this study a sensorially adequate saline solution (NaCl/KCl was simultaneously diffused during salting of Prato cheese in brine with agitation. The simultaneous multicomponent diffusion during the process was modeled with Fick’s second generalized law. The system of partial differential equations formed was solved by the finite element method (FEM. In the experimental data concentration the deviation for NaCl was of 7.3% and for KCl of 5.4%, both of which were considered acceptable. The simulation of salt diffusion will allow control and modulation of salt content in Prato cheese, permitting the prediction of final content from initial conditions.

  19. Electrochemical and surface studies on the passivity of a dental Pd-based casting alloy in alkaline sulphide solution

    Energy Technology Data Exchange (ETDEWEB)

    Endo, Kazuhiko; Ohno, Hiroki; Matsuda, Koichi; Asakura, Shukuji

    2003-07-01

    The corrosion and tarnish behavior of a dental casting Pd-25Ag-18Cu-12Au alloy in 0.1% Na{sub 2}S solution at 37 deg. C was investigated using potentiodynamic polarization and spectrocolorimetric techniques. The surface film was characterized by X-ray photoelectron spectroscopy (XPS). This alloy exhibited markedly higher resistance to corrosion and tarnish than did the Ag-20Pd-18Cu-12Au alloy in current clinical use. XPS spectra indicated the presence of a thin sulphide film composed of PdS. It was found that the PdS film is very protective and is responsible for the passivity of the Pd-25Ag-18Cu-12Au alloy in 0.1% Na{sub 2}S solution.

  20. Density, Viscosity, Solubility, and Diffusivity of N2O in Aqueous Amino Acid Salt Solutions

    NARCIS (Netherlands)

    Kumar, P. Senthil; Hogendoorn, J.A.; Feron, P.H.M.; Versteeg, G.F.

    2001-01-01

    Solubility and diffusivity of N2O in aqueous solutions of potassium taurate are reported over a wide range of concentration and temperature. Also, the solubility of N2O in aqueous potassium glycinate solution is reported at 295 K. The ion specific constants are reported for taurate and glycinate ani

  1. Effects of salt concentrations of the aqueous peptide-amphiphile solutions on the sol-gel transitions, the gelation speed, and the gel characteristics.

    Science.gov (United States)

    Otsuka, Takahiro; Maeda, Tomoki; Hotta, Atsushi

    2014-10-02

    Hydrogels made of peptide amphiphiles (PA) have attracted a lot of interest in biomedical fields. Considering the applications of PA hydrogels, the control of the gelation speed and the gel characteristics is essential to predominantly determine the usefulness and practicability of the hydrogels. In this work, the effects of the salt concentrations using sodium dihydrogenorthophosphate (NaH2PO4) on the sol-gel transition behaviors, especially the gelation speed and the gel characteristics of the designed PA (C16-W3K) hydrogels in aqueous solution were discussed. It was found that the original solution state before rheological testing was independent of the salt concentration, which was confirmed by observing the self-assembly structures and the peptide secondary structures of PA through transmission electron microscopy (TEM) and circular dichroism spectroscopy (CD). The PA solutions with different salt concentrations, however, presented a profound difference in the gelation speed and the gel characteristics: the solution exhibited higher gelation speeds and higher mechanical properties at higher salt concentrations. Concurrently, the density, the length of wormlike micelles, and the conformational ratio of β-sheets to α-helices in the equilibrium PA solutions all increased with the increase in the salt concentrations.

  2. Non-monotonic course of protein solubility in aqueous polymer-salt solutions can be modeled using the sol-mxDLVO model.

    Science.gov (United States)

    Herhut, Marcel; Brandenbusch, Christoph; Sadowski, Gabriele

    2016-02-01

    Protein purification is often performed using cost-intensive chromatographic steps. To discover economic alternatives (e.g., crystallization), knowledge on protein solubility as a function of temperature, pH, and additives in solution as well as their concentration is required. State-of-the-art models for predicting protein solubility almost exclusively consider aqueous salt systems, whereas "salting-in" and "salting-out" effects induced by the presence of an additional polymer are not considered. Thus, we developed the sol-mxDLVO model. Using this newly developed model, protein solubility in the presence of one salt and one polymer, especially the non-monotonic course of protein solubility, could be predicted. Systems considered included salts (NaCl, Na-p-Ts, (NH(4))(2) SO(4)) and the polymer polyethylene glycol (MW: 2000 g/mol, 12000 g/mol) and proteins lysozyme from chicken egg white (pH 4 to 5.5) and D-xylose ketol-isomerase (pH 7) at 298.15 K. The results show that by using the sol-mxDLVO model, protein solubility in polymer-salt solutions can be modeled in good agreement with the experimental data for both proteins considered. The sol-mxDLVO model can describe the non-monotonic course of protein solubility as a function of polymer concentration and salt concentration, previously not covered by state-of-the-art models.

  3. Novel one-step synthesis of wool-ball-like Ni-carbon nanotubes composite cathodes with favorable electrocatalytic activity for hydrogen evolution reaction in alkaline solution

    Science.gov (United States)

    Chen, Zhouhao; Ma, Zhipeng; Song, Jianjun; Wang, Lixin; Shao, Guangjie

    2016-08-01

    In this work, supergravity fields are performed to prepare Ni-CNTs composite cathodes with wool-ball-like morphology from the Watts bath containing well-distributed functionalized CNTs. The prepared Ni-CNTs composite cathodes are used as noble metal-free electrocatalyst with favorable electrocatalytic activity for hydrogen evolution reaction (HER) in alkaline solutions. The crystal structure and morphology of the composite cathodes are characterized by XRD and SEM measurements. The electrochemical activities of the cathodes are characterized through Tafel polarization measurement, electrochemical impedance spectroscopy and cyclic voltammetric study in 1.0 M NaOH solution. The results indicate that catalytic activities of the Ni-CNTs cathodes prepared under supergravity fields are enhanced significantly, and the sample prepared at rotating speed 3000 rpm from the bath containing 1 g dm-3 CNTs exhibits the highest HER activity with smallest Tafel slope and largest exchange current density of 823.9 μA cm-2. Furthermore, the effects of both the CNTs concentrations and the intensities of supergravity fields on the properties of the Ni-CNTs cathodes are investigated.

  4. Uranium mobility during interaction of rhyolitic obsidian, perlite and felsite with alkaline carbonate solution: T = 120° C, P = 210 kg/cm2

    Science.gov (United States)

    Zielinski, Robert A.

    1979-01-01

    Well-characterized samples of rhyolitic obsidian, perlite and felsite from a single lava flow are leached of U by alkaline oxidizing solutions under open-system conditions. Pressure, temperature, flow rate and solution composition are held constant in order to evaluate the relative importance of differences in surface area and crystallinity. Under the experimental conditions U removal from crushed glassy samples proceeds by a mechanism of glass dissolution in which U and silica are dissolved in approximately equal weight fractions. The rate of U removal from crushed glassy samples increases with decreasing average grain size (surface area). Initial rapid loss of a small component (≈ 2.5%) of the total U from crushed felsite. followed by much slower U loss, reflects variable rates of attack of numerous uranium sites. The fractions of U removed during the experiment ranged from 3.2% (felsite) to 27% (perlite). An empirical method for evaluating the relative rate of U loss from contemporaneous volcanic rocks is presented which incorporates leaching results and rock permeability data.

  5. Molten-salt synthesis and composition-dependent luminescent properties of barium tungsto-molybdate-based solid solution phosphors

    Science.gov (United States)

    Xiang-Hong, He; Zhao-Lian, Ye; Ming-Yun, Guan; Ning, Lian; Jian-Hua, Sun

    2016-02-01

    Pr3+-activated barium tungsto-molybdate solid solution phosphor Ba(Mo1-zWz)O4:Pr3+ is successfully fabricated via a facile molten-salt approach. The as-synthesized microcrystal is of truncated octahedron and exhibits deep-red-emitting upon blue light excitation. Powder x-ray diffraction and Raman spectroscopy techniques are utilized to investigate the formation of solid solution phosphor. The luminescence behaviors depend on the resulting composition of the microcrystals with fixed Pr3+-doping concentration, while the host lattices remain in a scheelite structure. The forming solid solution via the substitution of [WO4] for [MoO4] can significantly enhance its luminescence, which may be due to the fact that Ba(Mo1-zWz)O4:Pr3+ owns well-defined facets and uniform morphologies. Owing to its properties of high phase purity, well-defined facets, highly uniform morphologies, exceptional chemical and thermal stabilities, and stronger emission intensity, the resulting solid solution phosphor is expected to find potential applications in phosphor-converted white light-emitting diodes (LEDs). Project supported by the Construction Fund for Science and Technology Innovation Group from Jiangsu University of Technology, China, the Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, China (Grant No. KHK1409), the Priority Academic Program Development of Jiangsu Higher Education Institutions, China, and the National Natural Science Foundation of China (Grant No. 21373103).

  6. Use of alkali metal salts to prepare high purity single-walled carbon nanotube solutions and thin films

    Science.gov (United States)

    Ashour, Rakan F.

    Single-walled carbon nanotubes (SWCNTs) display interesting electronic and optical properties desired for many advanced thin film applications, such as transparent conductive electrodes or thin-film transistors. Large-scale production of SWCNTs generally results in polydispersed mixtures of nanotube structures. Since SWCNT electronic character (conducting or semiconducting nature) depends on the nanotube structure, application performance is being held back by this inability to discretely control SWCNT synthesis. Although a number of post-production techniques are able to separate SWCNTs based on electronic character, diameter, or chirality, most still suffer from the disadvantage of high costs of materials, equipment, or labor intensity to be relevant for large-scale production. On the other hand, chromatographic separation has emerged as a method that is compatible with large scale separation of metallic and semiconducting SWCNTs. In this work, SWCNTs, in an aqueous surfactant suspension of sodium dodecyl sulfate (SDS), are separated by their electronic character using a gel chromatography process. Metallic SWCNTs (m-SWCNTs) are collected as initial fractions since they show minimum interaction with the gel medium, whereas, semiconducting SWCNTs (sc- SWCNTs) remain adsorbed to the gel. The process of sc-SWCNT retention in the gel is found to be driven by the packing density of SDS around the SWCNTs. Through a series of separation experiments, it is shown that sc-SWCNTs can be eluted from the gel simply by disturbing the configuration of the SDS/SWCNT micellar structure. This is achieved by either introducing a solution containing a co-surfactant, such as sodium cholate (SC), or solutions of alkali metal ionic salts. Analysis of SWCNT suspensions by optical absorption provides insights into the effect of changing the metal ion (M+ = Li+, Na+, and K+) in the eluting solution. Salts with smaller metal ions (e.g. Li+) require higher concentrations to achieve

  7. Effect of ammonium-salt solutions on the surface properties of carbon fibers in electrochemical anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Qian Xin, E-mail: qx3023@nimte.ac.cn [National Engineering Laboratory of Carbon Fiber Preparation Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Wang Xuefei; Ouyang Qin; Chen Yousi; Yan Qing [National Engineering Laboratory of Carbon Fiber Preparation Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Longitudinal grooves on the fiber surface became more well-defined and much deeper after surface treatment. Black-Right-Pointing-Pointer The concentration of oxygen and nitrogen on the fiber surface increased after surface treatment. Black-Right-Pointing-Pointer The intensity of oxidative reaction varied with the change of ammonium-salt solutions. Black-Right-Pointing-Pointer The higher the concentration of OH{sup -} ions in the electrolytes, the violent the oxidative reaction happened. - Abstract: The surfaces of polyacrylonitrile-based carbon fibers were treated by an electrochemical anodic method. Three different kinds of ammonium-salt solutions namely NH{sub 4}HCO{sub 3}, (NH{sub 4}){sub 2}CO{sub 3} and (NH{sub 4}){sub 3}PO{sub 4} were respectively chosen as the electrolytes. The effect of these electrolytes on the surface structure was studied by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The results showed that longitudinal grooves on the fiber surface became more well-defined and much deeper after surface treatment, and the root mean square roughness (RMS) of carbon fiber surface increased from 4.6 nm for untreated fibers to 13.5 nm for treated fibers in (NH{sub 4}){sub 3}PO{sub 4} electrolytes. The concentration of oxygen and nitrogen atomic on the fiber surface increased after surface treatment. The tensile strength of oxidized fibers had an obvious decrease, whereas the interlaminar shear strength (ILSS) value of corresponding carbon fiber reinforced polymers (CFRPs) increased in a large extent. The intensity of oxidative reaction varied with the change of ammonium-salt solutions and electrochemical oxidation in (NH{sub 4}){sub 3}PO{sub 4} electrolyte was of the most violence. The corresponding mechanism was also discussed and the result showed that the higher the concentration of OH{sup -} ions in the electrolytes, the violent the oxidative

  8. 盐碱湖杆菌菌株MIM18的培养特性%Cultural Characteristics of a Bacterium,MIM18,Isolated from Salt Alkaline Lake

    Institute of Scientific and Technical Information of China (English)

    孟建宇; 李德林; 郑冬梅

    2013-01-01

    对分离自内蒙古自治区浑善达克盐碱湖的一株杆菌菌株MIM18的培养特征进行了研究.结果表明,该菌为革兰氏阳性杆菌,粉红色,分泌过氧化氢酶、精氨酸双水解酶和赖氨酸脱羧酶,对常见的抗生素高度敏感.生长盐浓度为0~55 g/L,最适盐浓度为10 g/L;温度范围24~40℃,最适温度33℃;pH 6.0~11.0,最适pH 9.5.好氧,属于兼性嗜碱菌.%The cultural characteristics of a strain,MIM18,isolated from the Hunshandake salt alkaline lake in Inner Mongolia were investigated.The results showed that the strain was found to be a gram-positive,rods and pink-pigmented bacterium,secreted catalase,arginine dihydrolase and lysine decarboxylase,was sensitive to common antibiotics.The strain was able to grow in 0~55 g/L total salts and the optimal concentration was 10 g/L.The range of temperature for this strain was 24~40 ℃ and the optimal temperature was 33 ℃.The range of pH was 6.0~ll.0 and the optimal pH was 9.5.This strain was aerobe and facultative alkalophile.

  9. Salt-induced vesicle formation from single anionic surfactant SDBS and its mixture with LSB in aqueous solution.

    Science.gov (United States)

    Zhai, Limin; Zhao, Mei; Sun, Dejun; Hao, Jingcheng; Zhang, Lungjun

    2005-03-31

    Vesicles can be formed spontaneously in aqueous solution of a single anionic surfactant sodium dodecyl benzenesulfonate (SDBS) just under the inducement of salt, which makes the formation of vesicle much easier and simpler. The existence of vesicles was demonstrated by TEM image using the negative-staining method. The mechanism of the formation may be attributed to the compression of salt on the electric bilayer of the surfactant headgroups, which alters the packing parameter of the surfactant. The addition of the zwitterionic surfactant lauryl sulfonate betaine (LSB) makes the vesicles more stable, expands the range of formation and vesicle size, and reduces the polydispersity of the vesicles. The vesicle region was presented in a pseudoternary diagram of SDBS/LSB/brine. The variations of vesicle size with the salinity and mixing ratios, as well as the surfactant concentration, were determined using the dynamic light scattering method. It is found that the vesicle size is independent of the surfactant concentration but subject to the salinity and the mixing ratio of the two surfactants.

  10. Results of Hg speciation testing on MCU strip effluent hold tank (SEHT) and decontaminated salt solution hold tank (DSSHT) materials

    Energy Technology Data Exchange (ETDEWEB)

    Bannochie, C. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-09-17

    The Savannah River National Laboratory (SRNL) was tasked with preparing and shipping samples for Hg speciation by Eurofins Frontier Global Sciences, Inc. in Seattle, WA on behalf of the Savannah River Remediation (SRR) Mercury Task Team.i,ii The tenth shipment of samples was designated to include Modular Caustic Side Solvent Extraction Unit (MCU) Strip Effluent Hold Tank (SEHT) and MCU Decontaminated Salt Solution Hold Tank (DSSHT) materials from processing Salt Batch 7b. The MCU SEHT (MCU-15-722) and DSSHT (MCU-15-709) samples were pulled on June 15, 2015. All MCU samples were received at SRNL on June 16, 2015. The DSSHT sample was moved the same day to refrigeration, while the SEHT sample was placed in the Shielded Cells. On July 9, 2015 it was opened and an aliquot diluted 1:100 with Eurofins deionized water and a portion of the diluted sample transferred to a Teflon® bottle prior to moving it to refrigeration that same day. All samples were kept in the dark and refrigerated until final dilutions were prepared for shipment to Eurofins.

  11. Study on extraction of xylan from corn cob with alkaline solution%玉米芯中木聚糖的碱法提取研究

    Institute of Scientific and Technical Information of China (English)

    汤卫华; 龙尾; 吕春晖

    2014-01-01

    木聚糖是存在于植物细胞壁中的重要聚合糖,玉米芯是木聚糖含量较高的农业纤维废弃物。采用不同的碱性物质对玉米芯中木聚糖进行提取,结果发现NaOH更适合木聚糖的提取。NaOH碱液提取木糖醇的最适提取条件为:NaOH浓度2.5 mol/L,料液比1 g∶10 mL,115℃提取60 min。在此条件下,木聚糖的提取率达到23.5%,该方法具有较高的应用价值。%Xylan is an important polymeric sugar in plant cell wall;corn cob is an agricultural fiber waste containing higher xylan content. Three alkaline solutions were used to extract xylan from corn cob, it was found that NaOH solution was more suitable for the extraction of xylan. The optimal extraction factors were showed that NaOH solution was 2.5 mol/L, solid-liquid ratio was 1 g∶10 mL,extraction temperature was 115℃and extraction time was 60 min. Under the above conditions, the yield of xylan was up to 23.5%.

  12. Effect of salt identity on the phase diagram for a globularprotein in aqueous electrolyte solution

    Energy Technology Data Exchange (ETDEWEB)

    Bostrom, Mathias; Tavares, Frederico W.; Ninham, Barry W.; Prausnitz, John M.

    2006-02-22

    Monte Carlo simulations are used to establish the potential of mean force between two globular proteins in an aqueous electrolyte solution. This potential includes nonelectrostatic contributions arising from dispersion forces first, between the globular proteins, and second, between ions in solution and between each ion and the globular protein. These latter contributions are missing from standard models. The potential of mean force, obtained from simulation, is fitted to an analytic equation. Using our analytic potential of mean force and Barker-Henderson perturbation theory, we obtain phase diagrams for lysozyme solutions that include stable and metastable fluid-fluid and solid-fluid phases when the electrolyte is 0.2 M NaSCN or NaI or NaCl. The nature of the electrolyte has a significant effect on the phase diagram.

  13. Numerical simulation of solidification in a horizontal cylindrical annulus charged with an aqueous salt solution

    Science.gov (United States)

    Neilson, D. G.; Incropera, F. D.; Bennon, W. D.

    1990-01-01

    A computational study of solidification of a binary Na2CO3 solution in a horizontal cylindrical annulus is performed using a continuum formulation with a control-volume based, finite-difference scheme. The initial conditions were selected to facilitate the study of counter thermal and solutal convection, accompanied by extensive mushy region growth. Numerical results are compared with experimental data with mixed success. Qualitative agreement is obtained for the overall solidification process and associated physical phenomena. However, the plume thickness calculated for the solutally-driven convective upflow is substantially smaller than the observed value. Evolution of double-diffusive layers is predicted, but over a time scale much smaller than that observed experimentally. Good agreement is obtained between predicted and measured results for solid growth, but the mushy region thickness is significantly overpredicted.

  14. Effect of salt solutions applied during wheat conditioning on lipase activity and lipid stability of whole wheat flour.

    Science.gov (United States)

    Doblado-Maldonado, Andrés F; Arndt, Elizabeth A; Rose, Devin J

    2013-09-01

    Lipolytic activity in whole wheat flour (WWF) is largely responsible for the loss in baking quality during storage. Metal ions affect the activity of seed lipases; however, no previous studies have applied this information to WWF in a way that reduces lipase activity, is practical for commercial manufacture, and uses common food ingredients. NaCl, KCl, Ca-propionate, or FeNa-ethylenediaminetetraacetic acid (FeNa-EDTA) were applied to hard red winter (HRW) and hard white spring (HWS) wheats during conditioning as aqueous solutions at concentrations that would be acceptable in baked goods. Salts affected lipase activity to different degrees depending on the type of wheat used. Inhibition was greater in HRW compared with HWS WWF, probably due to higher lipase activity in HRW wheat. In HRW WWF, 1% NaCl (flour weight) reduced hydrolytic and oxidative rancidity and resulted in higher loaf volume and lower firmness than untreated WWF after 24 weeks of storage.

  15. Copper-poly(2-aminodiphenylamine) as a novel and low cost electrocatalyst for electrocatalytic oxidation of methanol in alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Ojani, Reza, E-mail: fer-o@umz.ac.i [Electroanalytical Chemistry Research Laboratory, Faculty of Chemistry, University of Mazandaran, Babolsar (Iran, Islamic Republic of); Raoof, Jahan-Bakhsh; Ahmady-Khanghah, Yusef [Electroanalytical Chemistry Research Laboratory, Faculty of Chemistry, University of Mazandaran, Babolsar (Iran, Islamic Republic of)

    2011-03-30

    In the present work we demonstrate the carbon paste as a new electrode substrate for the electropolymerization of 2-aminodiphenylamine and fabrication of polymer film modified electrode. Then transition metal of copper is incorporated into the polymer by electrodepositing of Cu(II) from CuCl{sub 2} acidic solution using potentiostatic technique. The electrocatalytic oxidation of methanol was studies by cyclic voltammetry and chronoamperometry methods at the surface of obtained Cu/P(2ADPA)/MCPE. It has been found that in the course of an anodic potential sweep, the electro-oxidation of methanol follows the formation of Cu(III) and is catalyzed by this species through a mediated electron transfer mechanism. The obtained current density for this catalytic oxidation is very high which could be come from high surface area of caused by the P(2ADPA) modification. The effects of various parameters such as the copper loading, scan rate and methanol concentration on the electrocatalytic oxidation of methanol were also investigated at the surface of Cu/P(2ADPA)/MCPE. Finally, using a chronoamperometric method, the catalytic rate constant (k) for methanol was found to be 0.2 x 10{sup 5} cm{sup 3} mol{sup -1} s{sup -1} that the high k can be ascribed for the fast electron transfer process due to electrode modification.

  16. Effect of plasticizer on surface of free films prepared from aqueous solutions of salts of cationic polymers with different plasticizers

    Science.gov (United States)

    Bajdik, János; Fehér, Máté; Pintye-Hódi, Klára

    2007-06-01

    Acquisition of a more detailed understanding of all technological processes is currently a relevant tendency in pharmaceutical technology and hence in industry. A knowledge of film formation from dispersion of polymers is very important during the coating of solid dosage forms. This process and the structure of the film can be influenced by different additives. In the present study, taste-masking films were prepared from aqueous citric acid solutions of a cationic polymer (Eudragit ® E PO) with various hydrophilic plasticizers (glycerol, propylene glycol and different poly(ethylene glycols)). The mechanical properties, film thickness, wetting properties and surface free energy of the free films were studied. The aim was to evaluate the properties of surface of free films to predict the arrangement of macromolecules in films formed from aqueous solutions of salts of cationic polymers. A high molecular weight of the plasticizer decreased the work of deformation. The surface free energy and the polarity were highest for the film without plasticizer; the hydrophilic additives decreased these parameters. The direction of the change in polarity (a hydrophilic component caused a decrease in the polarity) was unexpected. It can be explained by the change in orientation of the macromolecules, a hydrophobic surface being formed. Examination of the mechanical properties and film thickness can furnish additional results towards a knowledge of film formation by this not frequently applied type of polymer from aqueous solution.

  17. Alkaline Waterflooding Demonstration Project, Ranger Zone, Long Beach Unit, Wilmington Field, California. Fourth annual report, June 1979-May 1980. Volume 1. Body of report

    Energy Technology Data Exchange (ETDEWEB)

    Carmichael, J.D.

    1981-03-01

    Comparative core flood testing of preserved Ranger Zone core rock samples was completed; the past year's results were discouraging. In contrast, Ranger sand pack alkaline flood tests gave encouraging results. New insights were gained on in-situ alkaline consumption. Dehydration of sodium orthosilicate water-produced water-crude oil systems does not appear to create any operational problems. The alkaline injection facilities were completed and placed in operation on March 27, 1980. The preflush injection, which was composed of 11.5 million barrels of softened fresh water with an average 0.96% of salt, was completed at that time. The total preflush amounted to approximately 10 pore volume percent. The 0.4% sodium orthosilicate-1.0% salt-soft fresh water injection started at the end of the preflush. A loss of injectivity began at the same time as alkaline injection, which is attributed to divalent ions in the salt brine. Salt was removed temporarily from the system on May 30, 1980. No injection wells were redrilled during the year. Other than plug back of one injector and one producer because of bad liners and repair of one injection well with an inner liner, well work was routine and minor in nature. Dual injection strings were transferred from one well to another. One of the injection wells whose injectivity was damaged by the alkaline-salt injection was successfully stimulated. The pilot was self certified under the tertiary incentive program and cost recoupments obtained. Preparations are underway for making the alkaline flood simulator performance prediction for the pilot. Laboratory testing is actively underway in an attempt to quickly find a remedy for the floc formation that occurs on mixing the salt brine and dilute alkaline solution. Volume 1 describes the activities for this period. Volumes 2 and 3 contain appendices.

  18. Electrocatalytic Oxidation of Formic Acid in an Alkaline Solution with Graphene-Oxide- Supported Ag and Pd Alloy Nanoparticles.

    Science.gov (United States)

    Han, Hyoung Soon; Yun, Mira; Jeong, Haesang; Jeon, Seungwon

    2015-08-01

    The electrocatalytic activities of metal-decorated graphene oxide (GO) catalysts were investigated. Electrochemically reduced GO-S-(CH2)4-S-Pd [ERGO-S-(CH2)4-S-Pd] and GO-S-(CH2)4-S-PdAg alloy [ERGO-S-(CH2)4-S-PdAg] were obtained through the electrochemical reduction of GO-S-(CH2)4-S-Pd and GO-S-(CH2)4-S-PdAg in a pH 5 PBS solution. It was demonstrated that the application of ERGO-S-(CH2)4-S-Pd and ERGO-S-(CH2)4-S-PdAg used in a modified GCE improves the electrocatalytic oxidation of formic acid. The addition of an Ag nanoparticle with a carbon chain-Pd in the electrode provides an electrode with very interesting properties for the electrocatalytic oxidation of formic acid. The ERGO-S-(CH2)4-S-Pd and ERGO-S-(CH2)4-S-PdAg were characterized via X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). ERGO-S-(CH2)4-S-Pd and ERGO-S-(CH2)4-S-PdAg can be employed for the electrocatalytic oxidation of formic acid. The electrochemical behaviors of this electrode were investigated using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS).

  19. Current-voltage behaviour of bipolar membranes in concentrated salt solutions investigated with chronopotentiometry

    NARCIS (Netherlands)

    Wilhelm, F.G.; Vegt, van der N.F.A.; Strathmann, H.; Wessling, M.

    2002-01-01

    Chronopotentiometry is used as a tool to obtain detailed information on the transport behaviour of the bipolar membrane BP-1 in solutions of high sodium chloride concentration above the limiting current density. We discuss critically the interpretation of the observed transition times. The occurrenc

  20. Influence of arbuscular mycorrhiza on organic solutes in maize leaves under salt stress.

    Science.gov (United States)

    Sheng, Min; Tang, Ming; Zhang, Fengfeng; Huang, Yanhui

    2011-07-01

    A pot experiment was conducted to examine the effect of the arbuscular mycorrhizal (AM) fungus, Glomus mosseae, on plant biomass and organic solute accumulation in maize leaves. Maize plants were grown in sand and soil mixture with three NaCl levels (0, 0.5, and 1.0 g kg(-1) dry substrate) for 55 days, after 15 days of establishment under non-saline conditions. At all salinity levels, mycorrhizal plants had higher biomass and higher accumulation of organic solutes in leaves, which were dominated by soluble sugars, reducing sugars, soluble protein, and organic acids in both mycorrhizal and non-mycorrhizal plants. The relative abundance of free amino acids and proline in total organic solutes was lower in mycorrhizal than in non-mycorrhizal plants, while that of reducing sugars was higher. In addition, the AM symbiosis raised the concentrations of soluble sugars, reducing sugars, soluble protein, total organic acids, oxalic acid, fumaric acid, acetic acid, malic acid, and citric acid and decreased the concentrations of total free amino acids, proline, formic acid, and succinic acid in maize leaves. In mycorrhizal plants, the dominant organic acid was oxalic acid, while in non-mycorrhizal plants, the dominant organic acid was succinic acid. All the results presented here indicate that the accumulation of organic solutes in leaves is a specific physiological response of maize plants to the AM symbiosis, which could mitigate the negative impact of soil salinity on plant productivity.

  1. Resuscitation from Hypovolemia in Swine with Intraosseous Infusion of a Saturated Salt-Dextran Solution (SSD)

    Science.gov (United States)

    1992-10-01

    weeks to ensure a good state of health, and fasted overnight before experimentation. Pre-anesthesia was induced with ketamine HCI (2 mg/kg), xylazine ...infusions of either isotonic or hypertonic solutions do not appear to be more dangerous than intravenous or intramuscular infusions. The use of the

  2. A study of substituent effect on the oxidative strengths of sodium salts of N-bromo-arylsulphonamides: Kinetics and mechanism of oxidation of D-fructose and D-glucose in alkaline medium

    Indian Academy of Sciences (India)

    K M Usha; B Thimme Gowda

    2006-07-01

    N-Bromo-arylsulphonamides of different oxidizing strengths are used for studying the kinetics of oxidation of D-fructose and D-glucose in aqueous alkaline medium. The results are analysed and compared with those from the sodium salts of N-bromo-benzenesulphonamide and N-bromo-4-methylbenzenesulphonamide. The reactions show zero-order kinetics in [oxidant], fractional order in [Fru/Glu] and nearly first order in [OH-]. Rates of oxidation of fructose are higher than those for glucose with the same oxidant. Similarly, values for glucose oxidations are higher than those for fructose. The results are explained by a suitable mechanism and the related rate law is deduced. The effective oxidising species in the reactions of N-bromo-arylsulphonamides is Br+. The oxidative strengths of the latter therefore depend on the ease with which Br+ is released from them. The ease with which Br+ is released from Nbromo- arylsulphonamides depends on the electron density on the nitrogen atom of the sulphonamide group, which in turn depends on the nature of the substituent on the benzene ring. The validity of the Hammett equation has also been tested for oxidation of both fructose and glucose. Enthalpies and entropies of activations of the oxidations by all the N-bromo-arylsulphonamides correlate well. The effect of substitution on and log of the oxidations is also considered.

  3. Influence of pH, temperature, and concentration on stabilization of aqueous hornet silk solution and fabrication of salt-free materials.

    Science.gov (United States)

    Kameda, Tsunenori

    2015-01-01

    We found that an aqueous solution of silk from cocoons produced by hornet larvae (hornet silk) can be obtained when the solution is adjusted to basic conditions of pH > 9.2. It is known that native hornet cocoons can be dissolved in concentrated aqueous solution of salts, such as lithium bromide (LiBr) and calcium chloride (CaCl2). Upon the removal of these salts from solution by dialysis, solidification, gelation, or sedimentation of hornet silk is known to occur. In the present study, under basic conditions, however, no such solidification occurred, even after salt removal. In this study, ammonia was used for alkalization of solution because it is volatilized during the casting process and pure hornet silk materials can be obtained after drying. The effects of the concentrations of hornet silk and ammonia, as well as dialysis temperature, on preventing gelation during dialysis were investigated. Dialysis conditions that limit the degradation of hornet silk by hydrolysis in alkali solution were identified. Moreover, casting conditions to prepare flexible and transparent hornet silk film from aqueous ammonia solution were optimized. Molecular structural analysis of hornet silk in aqueous ammonia solution and cast film indicated the formation of α-helix conformations.

  4. A novel chemiluminescence quenching method for determination of sulfonamides in pharmaceutical and biological fluid based on luminol-Ag(III) complex reaction in alkaline solution.

    Science.gov (United States)

    Sun, Hanwen; Chen, Peiyun; Li, Liqing; Cheng, Peng

    2011-05-01

    A novel chemiluminescence (CL) quenching method for the determination of sulfonamides is proposed. The CL reaction between Ag(III) complex [Ag(HIO₆)₂]⁵⁻ and luminol in alkaline solution was investigated. The quenching effect of sulfonamides on CL emission of [Ag(HIO₆)₂]⁵⁻-luminol system was found. Quenching degree of CL emission was proportional to sulfonamide concentration. The effects of the reaction conditions on CL emission and quenching were examined. Under optimal conditions, the detection limits (s/n = 3) were 7.2, 17 and 8.3 ng/mL for sulfadiazine, sulfameter, and sulfadimethoxine, respectively. The recoveries of the three drugs were in the range of 91.3-110% with RSDs of 1.9-2.7% for urine samples, and 106-112% with RSDs of 1.6-2.8% for serum samples. The proposed method was used for the determination of sulfadiazine at clinically relevant concentrations in real urine and serum samples with satisfactory results.

  5. Quantification of the dissolved inorganic carbon species and of the pH of alkaline solutions exposed to CO2 under pressure: a novel approach by Raman scattering.

    Science.gov (United States)

    Beuvier, Thomas; Calvignac, Brice; Bardeau, Jean-François; Bulou, Alain; Boury, Frank; Gibaud, Alain

    2014-10-07

    Dissolved inorganic carbon (DIC) content of aqueous systems is a key function of the pH, of the total alkanility (TA), and of the partial pressure of CO2. However, common analytical techniques used to determine the DIC content in water are unable to operate under high CO2 pressure. Here, we propose to use Raman spectroscopy as a novel alternative to discriminate and quantitatively monitor the three dissolved inorganic carbon species CO2(aq), HCO3(-), and CO3(2-) of alkaline solutions under high CO2 pressure (from P = 0 to 250 bar at T = 40 °C). In addition, we demonstrate that the pH values can be extracted from the molalities of CO2(aq) and HCO3(-). The results are in very good agreement with those obtained from direct spectrophotometric measurements using colored indicators. This novel method presents the great advantage over high pressure conventional techniques of not using breakable electrodes or reference additives and appears of great interest especially in marine biogeochemistry, in carbon capture and storage and in material engineering under high CO2 pressure.

  6. Mechanochemical synthesis, structure, and properties of solid solutions of alkaline earth metal fluorides: Ma1-xMbxF2 (M: Ca, Sr, Ba)

    Science.gov (United States)

    Heise, M.; Scholz, G.; Düvel, A.; Heitjans, P.; Kemnitz, E.

    2016-10-01

    The capability of mechanochemical synthesis for the formation of solid solutions of alkaline earth metal fluorides Ma1-xMbxF2 (M: Ca, Sr, Ba) was tested by fluorination of metal acetates and metal hydroxides with ammonium fluoride directly at milling. Evidence was found for a mutual substitution of cations on their lattice positions in Ca1-xSrxF2 and Ba1-xSrxF2 samples. For the Ba/Ca-system this synthesis route is only partially successful. X-ray diffraction and 19F MAS NMR spectroscopy were used to characterize all samples concerning their crystal structure and local fluorine coordination. Calculations of 19F chemical shifts with the superposition model along with probability calculations for the intensity of the individual 19F lines, performed in dependence on the molar composition of the samples, perfectly agree with the experimental findings. The fluoride ion conductivity of as-prepared samples, determined by temperature dependent DC conductivity measurements, is significantly higher than those of crystalline binary fluorides. Moreover, a higher F- ion conductivity is observed for samples with higher mixing grade in the Ca/Sr-and the Ba/Sr-systems.

  7. Estimation of kinetic parameters of the passive state of carbon steel in mildly alkaline solutions from electrochemical impedance spectroscopic and X-ray photoelectron spectroscopic data

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.; Wren, J.C. [Department of Chemistry, University of Western Ontario, 1151 Richmond St, London, Ontario, N6A 5B7 (Canada); Betova, I. [Department of Chemistry, Technical University of Sofia, 1000 Sofia (Bulgaria); Bojinov, M., E-mail: martin@uctm.edu [Department of Physical Chemistry, University of Chemical Technology and Metallurgy, 1756 Sofia (Bulgaria)

    2011-07-01

    Highlights: > The passive state of carbon steel is described using the Mixed-Conduction Model for oxide films. > Kinetic parameters are estimated by comparison of the model to EIS and XPS data. > The passive film is intermediate between magnetite and maghemite. > Relevance of film growth and dissolution reactions for corrosion is discussed. - Abstract: The unambiguous interpretation of electrochemical impedance spectra of complex systems such as passive metals and alloys in terms of an unique kinetic model is often hampered by the large number of adjustable modeling parameters. In this paper, a combination of in situ electrochemical data and ex situ surface analytical information is employed to validate the estimates of kinetic and transport parameters of the passive state of carbon steel. For the purpose, electrochemical impedance spectroscopic and X-ray photoelectron spectroscopic data for the oxidation of carbon steel in mildly alkaline solutions are quantitatively compared with the predictions of the Mixed-Conduction Model for oxide films that represent the passive oxide as an intermediate phase between magnetite and maghemite. Estimates of the kinetic rate constants at the film interfaces, as well as the diffusion coefficients and field strength in the film are obtained and their relevance for the corrosion mechanism of carbon steel is discussed.

  8. Graphene oxide electrocatalyst on MnO2 air cathode as an efficient electron pump for enhanced oxygen reduction in alkaline solution

    Science.gov (United States)

    Basirun, Wan Jeffrey; Sookhakian, Mehran; Baradaran, Saeid; Endut, Zulkarnain; Mahmoudian, Mohammad Reza; Ebadi, Mehdi; Yousefi, Ramin; Ghadimi, Hanieh; Ahmed, Sohail

    2015-03-01

    Graphene oxide (GO) was deposited on the surface of a MnO2 air cathode by thermal evaporation at 50°C from a GO colloidal suspension. Fourier transformed infrared spectroscopy and field emission scanning electron microscopy confirmed the presence of GO on the MnO2 air cathode (GO-MnO2). Voltammetry and chrono-amperometry showed increased currents for the oxygen reduction reaction (ORR) in 6 M KOH solution for GO-MnO2 compared to the MnO2 cathode. The GO-MnO2 was used as an air cathode in an alkaline tin-air cell and produced a maximum power density of 13 mW cm-2, in contrast to MnO2, which produced a maximum power density of 9.2 mW cm-2. The electrochemical impedance spectroscopy results suggest that the chemical step for the ORR is the rate determining step, as proposed earlier by different researchers. It is suggested that the presence of GO and electrochemically reduced graphene oxide (ERGO) on the MnO2 surface are responsible for the increased rate of this step, whereby GO and ERGO accelerate the process of electron donation to the MnO2 and to adsorbed oxygen atoms.

  9. Growth of lithium triborate single crystals from molten salt solution under various temperature gradients

    Science.gov (United States)

    Guretskii, S. A.; Ges, A. P.; Zhigunov, D. I.; Ignatenko, A. A.; Kalanda, N. A.; Kurnevich, L. A.; Luginets, A. M.; Milovanov, A. S.; Molchan, P. V.

    1995-12-01

    Single crystals of lithium triborate LiB 3O 5 (LBO) have been grown by the top-seeded solution growth method with B 2O 3 as a solvent using different temperature gradients in the zone of crystallization. Optical and nonlinear optical properties of LBO single crystals have been investigated. The influence of post-growth thermal treatment in oxygen atmosphere on the optical properties has been studied.

  10. OSMOTIC DEHYDRATION KINETICS OF GUAVAS IN MALTOSE SOLUTIONS WITH CALCIUM SALT*

    Directory of Open Access Journals (Sweden)

    S. DI S. MASTRANTONIO

    2009-03-01

    Full Text Available

    The osmotic dehydration kinetics of guavas in maltose solutions at 40 and 60ºBrix, with addition of 0, 0.6 and 1.2% of calcium lactate was studied in this paper and the final product quality was evaluated. The experiments were carried out up to 60 hours and samples were taken for analysis at different times to evaluate guavas weight reduction, water loss and sugar gain and to characterize the product according to its texture and color. After 24 hours of process the mass transfer of water and sugar between the osmotic solution and the fruit was negligible, showing that process equilibrium was reached. The increase of sugar concentration in the osmotic solution showed strong influence on the dehydration process, increasing the water loss and reducing sugar gain. The presence of calcium ions in the osmotic solution also influenced the kinetics of mass transfer and showed a strong influence on fruit texture. Higher values of stress and strain at failure were obtained when calcium lactate was employed. The effect of the different osmotic treatments on the color parameters was also investigated and significant changes were observed in the values of chroma C* and hue H* due to sugar concentration and calcium addition.

    KEYWORDS: Osmotic dehydration; kinetics; guava; maltose; calcium lactate.

  11. Mechanism of Pitting Corrosion Prevention by Nitrite in Carbon Steel Exposed to Dilute Salt Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Philip E. Zapp; John W. Van Zee

    2002-02-01

    The research has developed a broad fundamental understanding of the inhibition action of nitrite ions in preventing nitrate pitting corrosion of carbon steel tanks containing high-level radioactive waste. This fundamental understanding can be applied to specific situations during waste removal for permanent disposition and waste tank closure to ensure that the tanks are maintained safely. The results of the research provide the insight necessary to develop solutions that prevent further degradation.

  12. Tank Waste Transport Stability: Summaries of Hanford Slurry and Salt-Solution Studies in FY 2000

    Energy Technology Data Exchange (ETDEWEB)

    Welch, T.D.

    2002-07-08

    This report is a collection of summary articles on FY 2000 studies of slurry transport and salt-well pumping related to Hanford tank waste transfers. These studies are concerned with the stability (steady, uninterrupted flow) of tank waste transfers, a subset of the Department of Energy (DOE) Tanks Focus Area Tank (TFA) Waste Chemistry effort. This work is a collaborative effort of AEA Technology plc, the Diagnostic Instrumentation and Analysis Laboratory at Mississippi State University (DIAL-MSU), the Hemispheric Center for Environmental Technology at Florida International University (HCET-FIU), Numatec Hanford Corporation (NHC), and the Oak Ridge National Laboratory (ORNL). The purpose of this report is to provide, in a single document, an overview of these studies to help the reader identify contacts and resources for obtaining more detailed information and to help promote useful interchanges between researchers and users. Despite over 50 years of experience in transporting radioactive tank wastes to and from equipment and tanks at the Department of Energy's Hanford, Savannah River, and Oak Ridge sites, waste slurry transfer pipelines and process piping become plugged on occasion. At Hanford, several tank farm pipelines are no longer in service because of plugs. At Savannah River, solid deposits in the outlet line of the 2H evaporator have resulted in an unplanned extended downtime. Although waste transfer criteria and guidelines intended to prevent pipeline plugging are in place, they are not always adequate. To avoid pipeline plugging in the future, other factors that are not currently embodied in the transfer criteria may need to be considered. The work summarized here is being conducted to develop a better understanding of the chemical and waste flow dynamics during waste transfer. The goal is to eliminate pipeline plugs by improving analysis and engineering tools in the field that incorporate this understanding.

  13. Corrosion Tests of Steel Bar in Concrete under High Temperature by Salt Solution

    Energy Technology Data Exchange (ETDEWEB)

    Lee, ChangMin; Lee, YoonHee; Lee, KunJai [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Lee, KyungHo; Jang, HyunKie; Kim, JeongMook [Nuclear Engineering and Technology Institute, Daejeon (Korea, Republic of)

    2007-07-01

    The saturation of South Korea's at-reactor (AR) spent fuel storage pools has created necessity for additional spent fuel storage capacity. The utility company (Korea Hydro and Nuclear Power Company) is planning to construct a dry storage facility, which offers advantages such as no generation of second time radioactive waste, relatively low operational cost, and a short construction period. Spent nuclear fuel from CANDU will be stored in MACSTOR-400. MACSTOR-400 developed by KHNP and AECL is a new dry storage module to replace Korea's existing concrete silo. This module composed of reinforced concrete has a capacity of 446MgU, twice the MACSTOR 200. Concrete has been used in the construction of nuclear facilities because of two primary properties, its structural strength and its ability to shield radiation. The use of concrete in nuclear facilities for containment and shielding of radiation and radioactive materials has made its performance crucial for the safe operation of the facility. Corrosion of reinforcing bars deteriorates the concrete structures and reduces their service life. Because spent fuel dry storage will be constructed near seashore, the reinforced concrete components and structures must withstand the damage due to salt attack under high temperature that is emitted by spent fuel. It can be noted that the temperature considerably affects degradation of reinforced concrete structure. However, there are very few examination examples to make clear the influence of the temperature. To obtain the basic material properties at high temperature and evaluate life time of spent fuel dry storage facility, the following test is now in progress.

  14. Structure and reactivity of thiazolium azo dyes: UV-visible, resonance Raman, NMR, and computational studies of the reaction mechanism in alkaline solution.

    Science.gov (United States)

    Abbott, Laurence C; Batchelor, Stephen N; Moore, John N

    2013-03-07

    UV-visible absorption, resonance Raman, and (1)H NMR spectroscopy, allied with density functional theory (DFT) calculations, have been used to study the structure, bonding, and alkaline hydrolysis mechanism of the cationic thiazloium azo dye, 2-[2-[4-(diethylamino)phenyl]diazenyl]-3-methyl-thiazolium (1a), along with a series of six related dyes with different 4-dialkylamino groups and/or other phenyl ring substituents (2a-c, 3a-c) and the related isothiazolium azo dye, 5-[2-[4-(dimethylamino)phenyl]diazenyl]-2-methyl-isothiazolium (4). These diazahemicyanine dyes are calculated to have a similar low-energy structure that is cis, trans at the (iso)thiazolium-azo group, and for which the calculated Raman spectra provide a good match with the experimental data; the calculations on these structures are used to assign and discuss the transitions giving rise to the experimental spectra, and to consider the bonding and its variation between the dyes. UV-visible, Raman, and NMR spectra recorded from minutes to several weeks after raising the pH of an aqueous solution of 1a to ca. 11.5 show that the dominant initial step in the reaction is loss of diethylamine to produce a quinonimine (ca. hours), with subsequent reactions occurring on longer time scales (ca. days to weeks); kinetic analyses give a rate constant of 2.6 × 10(-2) dm(3) mol(-1) s(-1) for reaction of 1a with OH(-). UV-visible spectra recorded on raising the pH of the other dyes in solution show similar changes that are attributed to the same general reaction mechanism, but with different rate constants for which the dependence on structure is discussed.

  15. Different sodium salts cause different solute accumulation in the halophyte Prosopis strombulifera.

    Science.gov (United States)

    Llanes, A; Bertazza, G; Palacio, G; Luna, V

    2013-01-01

    The success of Prosopis strombulifera in growing under high NaCl concentrations involves a carefully controlled balance among different processes, including compartmentation of Cl(-) and Na(+) in leaf vacuoles, exclusion of Na(+) in roots, osmotic adjustment and low transpiration. In contrast, Na(2) SO(4) causes growth inhibition and toxicity. We propose that protection of the cytoplasm can be achieved through production of high endogenous levels of specific compatible solutes. To test our hypothesis, we examined endogenous levels of compatible solutes in roots and leaves of 29-, 40- and 48-day-old P. strombulifera plants grown in media containing various concentrations of NaCl, Na(2) SO(4) or in mixtures of both, with osmotic potentials of -1.0,-1.9 and -2.6 MPa, as correlated with changes in hydric parameters. At 24 h after the last pulse plants grown in high NaCl concentrations had higher relative water content and relatively higher osmotic potential than plants grown in Na(2) SO(4) (at 49 days). These plants also had increased synthesis of proline, pinitol and mannitol in the cytoplasm, accompanied by normal carbon metabolism. When the sulphate anion is present in the medium, the capacities for ion compartmentalisation and osmotic adjustment are reduced, resulting in water imbalance and symptoms of toxicity due to altered carbon metabolism, e.g. synthesis of sorbitol instead of mannitol, reduced sucrose production and protein content. This inhibition was partially mitigated when both anions were present together in the solution, demonstrating a detrimental effect of the sulphate ion on plant growth.

  16. Oxidative Leaching of metals from electronic waste with solutions based on quaternary ammonium salts

    OpenAIRE

    Pinheiro, Diana

    2009-01-01

    The treatment of electric and electronic waste (WEEE) is a problem which receives ever more attention. An inadequate treatment results in harmful products ending up in the environment. This project intends to investigate the possibilities of an alternative route for recycling of metals from printed circuit boards (PCBs) obtained from rejected computers. The process is based on aqueous solutions composed of an etchant, either 0.2 M CuCl2.2H2O or 0.2 M FeCl3.6H2O, and a quater...

  17. Study of quantitative interactions of potato and corn starch granules with ions in diluted solutions of heavy metal salts.

    Science.gov (United States)

    Szymońska, Joanna; Molenda, Marcin; Wieczorek, Jerzy

    2015-12-10

    Interactions of potato and corn starch granules with ions in diluted solutions of silver, lead, copper or iron salts were investigated. It was shown experimentally that granules accumulated the cations in amounts depending on the granule structure and water content as well as a type of both metal and counter-ions present in solution. Potato starch retained almost three times more cations compared to corn starch what was proportional to the total phosphorous content in these starches. Quantity of milligrams of cations bound by 1g of starch was inversely correlated with the cation hydration. Ag(+), Pb(2+) and Cu(2+) were connected in stoichiometric amounts of moles to semicrystalline and amorphous parts of the granules. Fe(3+) ions were accumulated in higher than stoichiometric quantities mainly in granule amorphous regions. Metal ions penetrated into granules together with anions except nitrates which remained on surface of potato starch granules. Cations facilitated the starch thermal decomposition in accordance with values of their standard redox potentials. Nitrates supported this process only in the presence of base metal cations.

  18. Organic solutes in coconut palm seedlings under water and salt stresses

    Directory of Open Access Journals (Sweden)

    Alexandre R. A. da Silva

    Full Text Available ABSTRACT The objective of this study was to investigate the biochemical mechanisms associated with isolated and/or concurrent actions of drought and soil salinity in seedlings of coconut tree, through the accumulation of organic solutes (soluble carbohydrates, soluble amino N and free proline in leaves and roots. The experiment, conducted in a protected environment, in Fortaleza, Brazil, in a randomized block design, in a split-plot arrangement, evaluated the effects of different levels of water stress (plots by imposing distinct percentages of replacement of water losses through crop potential evapotranspiration - ETpc (20, 40, 60, 80 and 100%, associated with subplots consisting of increasing levels of soil salinity in saturation extract (1.72, 6.25, 25.80 and 40.70 dS m-1 provided by the soils collected in the Irrigated Perimeter of Morada Nova. Salinity did not change the concentration of organic solutes; however, there were increases in leaf and root levels of free proline in response to water stress, which contributes to the osmoregulation and/or osmoprotection of the species under adverse conditions of water supply.

  19. Use of a liter-scale microbial desalination cell as a platform to study bioelectrochemical desalination with salt solution or artificial seawater.

    Science.gov (United States)

    Jacobson, Kyle S; Drew, David M; He, Zhen

    2011-05-15

    Bioelectrochemical desalination is potentially advantageous because of bioenergy production and integrated wastewater treatment and desalination. In this work, the performance and energy benefits of a liter-scale upflow microbial desalination cell (UMDC) were evaluated. The UMDC desalinated both salt solution (NaCl) and artificial seawater, and the removal rate of total dissolved solid (TDS) increased with an increased hydraulic retention time, although TDS reduction in artificial seawater was lower than that in salt solution. Our analysis suggested that electricity generation was a predominant factor in removing TDS (more than 70%), and that other factors, like water osmosis and unknown processes, also contributed to TDS reduction. It was more favorable given the high energy efficiency, when treating salt solution, to operate the UMDC under the condition of high power output compared with that of high current generation because of the amount of energy production; while high current generation was more desired with seawater desalination because of lower salinity in the effluent. Under the condition of the high power output and the assumption of the UMDC as a predesalination in connection with a reversal osmosis (RO) system, the UMDC could produce electrical energy that might potentially account for 58.1% (salt solution) and 16.5% (artificial seawater) of the energy required by the downstream RO system. Our results demonstrated the great potential of bioelectrochemical desalination.

  20. BrCl production in NaBr/NaCl/HNO3/O3 solutions representative of sea-salt aerosols in the marine boundary layer

    Science.gov (United States)

    Disselkamp, R. S.; Chapman, E. G.; Barchet, W. R.; Colson, S. D.; Howd, C. D.

    Atomic bromine and chlorine liberated from sea-salt aerosol is thought to play an important role in chemistry of the marine boundary layer. Despite numerous modeling studies, no prior experimental investigations of the oxidation of halide species contained in simulated, or actual, sea-salt solutions have been performed. We present laboratory data that examines chemistry in NaBr/NaCl/HNO3/O3 solutions at 290 K. Ozonation experiments were performed by flowing ozone in air through a nitric acid/salt solution and monitoring pH with time using an ion-sensitive electrode. The rate of oxidation was observed to be first order in ozone concentration and to have a non-first order bromide concentration dependence. Ion Chromatography was used to measure both bromide disappearance as well as oxidation products formed during the course of the reactions studied. Our measurements of the oxidation rate versus ion concentration indicate that the high ionic strength present in sea-salt aerosol will possess unique kinetics different from dilute solution behavior. In addition, our results are consistent with the reaction sequence O3 + H+ + Br- → O2 + HOBr and HOBr + Cl- + H+ → BrCl + H2O. These observations support the HOBr mediated Cl- oxidation process proposed previously (Vogt et al., 1996).

  1. Quasi-elastic laser light scattering study of polyacrylamide hydrogel immersed in water and salt solutions

    Indian Academy of Sciences (India)

    M Sivanantham; B V R Tata

    2010-12-01

    Polyacrylamide (PAAm) hydrogels immersed in water and aqueous NaCl solutions were investigated for their structure and dynamics using static and quasi-elastic laser light scattering (QELS) techniques. Ensemble-averaged electric field correlation function (, ) obtained from the non-ergodic analysis of intensity-autocorrelation function for PAAm gel immersed in water and in 5 M NaCl showed an exponential decay to a plateau with an initial decay followed by saturation at long times. The value of the plateau was found to depend on NaCl concentration and was higher than that of water. Collective diffusion coefficient, , of the polymer network of the hydrogel immersed in water and in different concentrations of NaCl was determined by analysing (, ). The measured diffusion coefficient showed linear decrease with increase in concentration of NaCl. The characteristic network parameters were obtained by analyzing (, ) with harmonically bound Brownian particle model and from static light scattering studies.

  2. Development, survival and reproduction of Podisus nigrispinus (Dallas, 1851 (Heteroptera: Pentatomidae with salt and amino acids solutions supplementary diet

    Directory of Open Access Journals (Sweden)

    Simone Patrícia Carneiro Freitas

    2006-05-01

    Full Text Available This study presents the effect of a supplementary diet with amino acids and sodium chloride solutions in addition to prey on the development, survival and reproduction of the predator Podisus nigrispinus (Heteroptera, Pentatomidae. Both solutions showed deleterious effects on nymph survival, adult weight, female longevity, number of egg masses, eggs per female, eggs per egg mass and nymphs per female besides egg viability of P. nigrispinus when compared with diet with water and prey. When compared with plant supplements in the diet the use of amino acids and salt solutions for mass rearing of P. nigrispinus was inferior.O presente estudo mostra o efeito da suplementação alimentar com soluções de aminoácidos e salina (NaCl no desenvolvimento, sobrevivência e reprodução de Podisus nigrispinus (Dallas (Heteroptera: Pentatomidae. Ambas soluções causaram efeito deletério na sobrevivência ninfal, peso dos adultos, longevidade das fêmeas e nos números de posturas, de ovos/fêmea, de ovos/postura e de ninfas, bem como na viabilidade dos ovos de P. nigrispinus quando comparado com estes insetos que além de presa receberam água. Estes resultados são discutidos em comparação com o efeito positivo que a suplementação alimentar com plantas tem sido relatada para esses predadores e sugerem que o uso de plantas é melhor que a substituição por solução de aminoácidos em sistemas de criação em laboratório desses predadores.

  3. Interfacial behavior of perchlorate versus chloride ions in saturated aqueous salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Ghosal, S; Kuo, I W; Baer, M D; Bluhm, H

    2009-04-14

    In recent years combination of theoretical and experimental work have presented a novel view of the aqueous interface wherein hard and/or multiply charged ions are excluded from the interface, but large polarizable anions show interfacial enhancement relative to the bulk. The observed trend in the propensity of anions to adsorb at the air/water interface appears to be reverse of the Hofmeister series for anions. This study focuses on experimental and theoretical examination of the partitioning behavior of perchlorate (ClO{sub 4}{sup -}) and chloride (Cl{sup -}) ions at the air/water interface. We have used ambient pressure X-ray photoelectron spectroscopy technique to directly probe the interfacial concentrations of ClO{sub 4}{sup -} and Cl{sup -} ions in sodium perchlorate and sodium chloride solutions, respectively. Experimental observations are compared with first principles molecular dynamics simulations. Both experimental and simulation results show enhancement of ClO{sub 4}{sup -} ion at the interface, compared with the absence of such enhancement in the case of Cl{sup -} ion. These observations are in agreement with the expected trend in the interfacial propensity of anions based on the Hofmeister series.

  4. Synthesis and Uptake of the Compatible Solutes Ectoine and 5-Hydroxyectoine by Streptomyces coelicolor A3(2) in Response to Salt and Heat Stresses▿

    OpenAIRE

    Bursy, Jan; Kuhlmann, Anne U.; Pittelkow, Marco; Hartmann, Holger; Jebbar, Mohamed; Pierik, Antonio J.; Bremer, Erhard

    2008-01-01

    Streptomyces coelicolor A3(2) synthesizes ectoine and 5-hydroxyectoine upon the imposition of either salt (0.5 M NaCl) or heat stress (39°C). The cells produced the highest cellular levels of these compatible solutes when both stress conditions were simultaneously imposed. Protection against either severe salt (1.2 M NaCl) or heat stress (39°C) or a combination of both environmental cues could be accomplished by adding low concentrations (1 mM) of either ectoine or 5-hydroxyectoine to S. coel...

  5. Inclusion of mPRISM potential for polymer-induced protein interactions enables modeling of second osmotic virial coefficients in aqueous polymer-salt solutions.

    Science.gov (United States)

    Herhut, Marcel; Brandenbusch, Christoph; Sadowski, Gabriele

    2016-01-01

    The downstream processing of therapeutic proteins is a challenging task. Key information needed to estimate applicable workup strategies (e.g. crystallization) are the interactions of the proteins with other components in solution. This information can be deduced from the second osmotic virial coefficient B22 , measurable by static light scattering. Thermodynamic models are very valuable for predicting B22 data for different process conditions and thus decrease the experimental effort. Available B22 models consider aqueous salt solutions but fail for the prediction of B22 if an additional polymer is present in solution. This is due to the fact that depending on the polymer concentration protein-protein interactions are not rectified as assumed within these models. In this work, we developed an extension of the xDLVO model to predict B22 data of proteins in aqueous polymer-salt solutions. To show the broad applicability of the model, lysozyme, γ-globulin and D-xylose ketol isomerase in aqueous salt solution containing polyethylene glycol were considered. For all proteins considered, the modified xDLVO model was able to predict the experimentally observed non-monotonical course in B22 data with high accuracy. When used in an early stage in process development, the model will contribute to an efficient and cost effective downstream processing development.

  6. Hank?s balanced salt solution: an alternative resuspension medium to label autologous leukocytes. Experience in inflammatory bowel disease

    Directory of Open Access Journals (Sweden)

    Martin-Comin Joseph

    2002-01-01

    Full Text Available In this work Hank's balanced salt solution (HBSS has been used, as resuspension medium, instead of leukocyte poor plasma (LPP to label autologous white blood cells in 28 patients with suspicion af active inflammatory bowel disease.Labelled cells were reinjected and anterior and caudo-craneal views were obtained at 30 min, 2 h and 6 h p.i. Regions of interest were outlined on liver, spleen, lung, bone marrow (spine, background and lesions and the organ/background activity ratios were calculated in all scans. Patients were classified into 2 groups: Group 1: LPP, 30 patients and Groups 2: HBSS, 28 patients. Labelling efficiency was higher in HBBS group (89.0 ± 3.2 % than in the LPP group (6.5 ± 6.3%. Organ/background activity ratios were similar in both groups. Concerning diagnostic accuracy was similar at 30 min and 2 h but the false positive rate increased at 6 h p.i. in the HBSS group. HBSS seems to be a valid alternative as resuspension medium in the labeling of autologous leukocytes but leukocyte poor plasma seem to induce less leukocyte damage. Based on these results, in our center HBSS is the currently used medium to label leukocytes.

  7. Hank's balanced salt solution: an alternative resuspension medium to label autologous leukocytes. Experience in inflammatory bowel disease

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Comin, Joseph; Plaza, Pedro; Roca, Manoel [Hospital de Bellvitge (Spain). Servico de Medicina Nuclear]. E-mail: jmartincomin@csub.scs.es; Cardoso, Valbert Nascimento [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Faculdade de Farmacia

    2002-09-01

    In this work Hank balanced salt solution (HBSS) has been used as resuspension medium, instead of leukocyte poor plasma (LPP) to label autologous white blood cells in 28 patients with suspicion of active inflammatory bowel disease. Labelled cells were reinjected and anterior and caudo-cranial views were obtained at 30 min, 2 h and 6 h p.i. Regions of interest were outlined on liver, spleen, lung, bone marrow (spine), background and lesions and the organ/background activity ratios were calculated in all scans. Patients were classified into 2 groups: Group 1: LPP, 30 patients and Groups 2: HBSS, 28 patients. labelling efficiency was higher in HBSS group (89.0 +- 3.2%) than in the LPP group (6.5 +- 6.3%). Organ/background activity ratios were similar in both groups. Concerning diagnostic accuracy was similar at 30 min and 2 h but the false positive rate increased at 6 h p.i. in the HBSS group. HBSS seems to be a valid alternative as resuspension medium in the labeling of autologous leukocytes but leukocyte poor plasma seem to induce less leukocyte damage. Based on these results, in our center HBSS is the currently used medium to label leukocytes. (author)

  8. Obtainment of Hg-free Mn/Zn solutions from spent alkaline batteries; Obtencion de soluciones de Mn/Zn libres de Hg provenientes de pilas alcalinas gastadas

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Nicolas, L.; Espinosa-Ramirez, I. [Instituto Politecnico Nacional, UPALM, Mexico, D.F. (Mexico)]. E-mail: lepeni@hotmail.com; Aguilar, M. [Instituto de Fisica, UNAM, Mexico, D.F. (Mexico); Palacios-Beas, E. [Instituto Politecnico Nacional, UPALM, Mexico, D.F. (Mexico)

    2009-09-15

    As in many other countries, the excessive consumption of alkaline batteries in Mexico has generated highly contaminating wastes, with heavy metal contents such as Mn, Zn, Fe, Hg, Cu and Ni, among others. This has caused a large degree of environmental degradation with repercussions for the health of living beings. Because there are no regulations regarding the disposal of spent batteries, they are thrown out with the rest of the domestic wastes or directly into nature, ending up in open-air landfills or containers where they are incinerated, thereby contaminating the planet's environment, soil and springs. The present work studies the obtainment of solutions of Hg-free Mn and Zn (Mn/Zn {>=} 1) from spent alkaline batteries for use in synthesis of (Mn,Zn)Fe{sub 2}O{sub 4} ferrite by a wet method. The effect is analyzed of the dissolution medium (H{sub 2}SO{sub 4}/H{sub 2}O{sub 2}, HCl and HCl/NO{sub 3}) temperature and time on the percentage of dissolution of the metals present in the electrode material, characterized by atomic absorption (AA) spectroscopy and x-ray diffraction (XRD). The results of the investigation indicate that the best dissolution conditions are MD=H{sub 2}SO{sub 4}/H{sub 2}O{sub 2}, T=50 degrees Celsius and t =30 min, where 94.1 and 90.7 % (w/w) of Mn and Zn are obtained, respectively, with Mn/Zn = 1.51. The mercury content was determined to be 3.91%, higher than that stated by the battery specifications, which is recovered by dissolving with HCl/HNO{sub 3} in the residual solid. [Spanish] En Mexico como en muchos otros paises, el consumo excesivo de pilas alcalinas ha generado desechos altamente contaminantes, con contenidos de metales pesados como Mn, Zn, Fe, Hg, Cu y Ni entre otros, que han provocado un gran deterioro en el medio ambiente repercutiendo en la salud de los seres vivos. Dado que no se tiene una regulacion en cuanto a la disposicion de pilas gastadas, estas se desechan con el resto de las residuos domesticos o directamente

  9. Morphological and physiological response ofHippophae rhamnoides on alkaline salt stress%沙棘对碱性盐胁迫的形态和生理响应

    Institute of Scientific and Technical Information of China (English)

    于畅; 王竞红; 薛菲; 江远芳

    2014-01-01

    H. rhamnoides seedlings were different when the types of salt-alkali stress varied, the single salt’s effect was more than complex salt’s, the alkaline salt’s damage was stronger than others, that is to say Na2CO3>NaHCO3>[Na2CO3 and NaHCO3]. Theifndings provide a technical support in slope-protection project with H. rhamnoides seedlings in northeast of China.

  10. Marinade with alkaline solutions for the improvement of pork quality Marinados com soluções alcalinas para a melhoria da qualidade da carne suína

    Directory of Open Access Journals (Sweden)

    Viviane Maria Oliveira dos Santos

    2012-11-01

    Full Text Available The objective of this work was to evaluate the effects of alkaline solution marinades on the characteristics of pork subjected to post-mortem pH decrease in pig muscle. The pH of carcasses was measured in a commercial slaughterhouse (n = 526, 45 min after slaughtering (pH45 and, then, the carcasses were divided into the groups with pH455.7. Ten samples of the longissimus dorsi muscles of each group were collected and distributed in an entirely randomized design, in a 2x4 factorial arrangement, with two conditions (pH455.7, and four marinade solutions: TC, no marinade; TM1, sodium bicarbonate and sodium chloride; TM2, sodium tripolyphosphate and sodium chloride; TM3, sodium bicarbonate, sodium tripolyphosphate and sodium chloride. There was no interaction between pH45 of the meat and the marinade treatments. Meat with pH45O objetivo deste trabalho foi avaliar os efeitos de marinadas com soluções alcalinas sobre características da carne de porco submetida a quedas do pH post-mortem, em músculo de porco. O pH das carcaças foi medido em abatedouro comercial (n = 526, aos 45 min pós-abate (pH45 e, em seguida, as carcaças foram divididas em grupos com pH455,7. Dez amostras do músculo longissimus dorsi de cada grupo foram coletadas e distribuídas em delineamento inteiramente casualizado, em arranjo fatorial 2x4, com duas condições (pH455,7 e quatro soluções de marinação: TC, controle sem marinação; TM1, bicarbonato de sódio e cloreto de sódio; TM2, tripolifosfato de sódio e cloreto de sódio; TM3, bicarbonato de sódio, tripolifosfato de sódio e cloreto de sódio. Não houve interação entre o pH45 da carne e os tratamentos marinados. As carnes com pH45<5,7 apresentaram maior luminosidade, perda por purga (PP, perda de exsudato (PE, perda de peso por cozimento (PC e força de cisalhamento (FC. A marinação aumentou o pH da carne, reduziu a luminosidade, PE, PC e FC, e melhorou a maciez, suculência e palatabilidade. As marinadas

  11. Effects of salt or cosolvent addition on solubility of a hydrophobic solute in water: Relevance to those on thermal stability of a protein

    Science.gov (United States)

    Murakami, Shota; Hayashi, Tomohiko; Kinoshita, Masahiro

    2017-02-01

    The solubility of a nonpolar solute in water is changed upon addition of a salt or cosolvent. Hereafter, "solvent" is formed by water molecules for pure water, by water molecules, cations, and anions for water-salt solution, and by water and cosolvent molecules for water-cosolvent solution. Decrease and increase in the solubility, respectively, are ascribed to enhancement and reduction of the hydrophobic effect. Plenty of experimental data are available for the change in solubility of argon or methane arising from the addition. We show that the integral equation theory combined with a rigid-body model, in which the solute and solvent particles are modeled as hard spheres with different diameters, can reproduce the data for the following items: salting out by an alkali halide and salting in by tetramethylammonium bromide, increase in solubility by a monohydric alcohol, and decrease in solubility by sucrose or urea. The orders of cation or anion species in terms of the power of decreasing the solubility can also be reproduced for alkali halides. With the rigid-body model, the analyses are focused on the roles of entropy originating from the translational displacement of solvent particles. It is argued by decomposing the solvation entropy of a nonpolar solute into physically insightful constituents that the solvent crowding in the bulk is a pivotal factor of the hydrophobic effect: When the solvent crowding in the bulk becomes more serious, the effect is strengthened, and when it becomes less serious, the effect is weakened. It is experimentally known that the thermal stability of a protein is also influenced by the salt or cosolvent addition. The additions which decrease and increase the solubility of a nonpolar solute, respectively, usually enhance and lower the thermal stability. This suggests that the enhanced or reduced hydrophobic effect is also a principal factor governing the stability change. However, urea decreases the solubility but lowers the stability

  12. On the role of salt type and concentration on the stability behavior of a monoclonal antibody solution.

    Science.gov (United States)

    Arosio, Paolo; Jaquet, Baptiste; Wu, Hua; Morbidelli, Massimo

    2012-07-01

    Protein-salt interactions regulate protein solubility and stability and in particular several protein related processes, such as salting-out and aggregation. Using an IgG2 monoclonal antibody as a model multi-domain therapeutic protein, we have investigated the salt effect on the reversible formation of protein clusters with small aggregation number. The oligomer formation has been quantified by size exclusion chromatography (SEC). It is found that the salt effect is strongly ion specific and pH dependent. In particular, at pH 3.0 only anions affect the aggregation propensity, while at pH 4.0 both anions and cations influence the aggregation rate. The ranking of the anion effect follows the Hofmeister series with the only exception of sulfate, while that of the cation effect does not. In addition, a maximum of the aggregation propensity as a function of salt concentration is observed (i.e., presence of re-stabilization). By correlating the aggregation kinetics to the experimental investigation of protein structure and surface energy, it is shown that changes in pH and salt concentration induce aggregation not only through charge screening and various solvation forces, but also through the formation of protein intermediates characterized by partially ordered structures and certain degrees of hydrophobicity. The complex interaction between the solvation forces and such protein secondary structures induced by salts explains the observed experimental results relative to re-stabilization at large salt concentrations, ion specificity and the peculiar behavior of the sulfate anion.

  13. Solute accumulation and distribution traits of an alkali resistant forage plant Kochia sieversiana and physiological contribution of organic acid under salt and alkali stresses%盐碱胁迫下抗碱牧草碱地肤溶质积累、分布特点及有机酸的生理贡献

    Institute of Scientific and Technical Information of China (English)

    麻莹; 郭立泉; 张淑芳; 王晓苹; 石德成

    2013-01-01

    对碱地肤幼苗进行盐、碱胁迫处理,通过测定各种溶质积累及分布特点,探讨碱地肤适应盐碱生境生理机制的部位差异,明确有机酸对其适应盐碱生境的贡献.结果表明,各种溶质在幼叶、成熟叶、幼茎、老茎及根等不同部位的分布存在明显差异,其中无论胁迫与否,有机酸均主要分布在茎叶之中,特别是在决定光合生产力的成熟叶片中.Na+、K+、Ca2+在不同部位的分布规律基本一致,表明Na+对K+、Ca2+的吸收与转运不存在拮抗竞争作用.实验证明了K+、Ca2+特殊的吸收机制及各溶质的分布特点对碱地肤抗盐碱生理是至关重要的;不论在盐胁迫还是碱胁迫下,有机酸在碱地肤不同部位特别是成熟叶中,均是参与渗透调节、离子平衡及pH调节的主导成分,是决定碱地肤适应盐碱生境的关键物质之一.实验同时也证明了碱地肤的不同部位对盐碱胁迫的适应机制有所不同.%The accumulation and distribution characteristics of various solutes from Kochia sieversiana seedlings stressed by salt and alkali were measured to study the physiological mechanisms in different parts of K. sieversiana and their role in adaptability to salt-alkalinized soil, and to identify the contribution of organic acid to salt-alkalinized habitat adaptability. There were considerable differences in the distribution of various solutes from different plant parts such as young leaves, mature leaves, young stems, old stems and roots. Organic acid was distributed mainly in stems and leaves, especially in mature and functional leaves on which photosynthetic productivity was dependent. Distributions of Na+ , K+ and Ca2+ in different plant parts were uniform on the whole indicating that there was no competition for Na+ , K+ and Ca2+ for absorption and transportation. Special absorption mechanisms of K+ and Ca2+ and distribution characteristics of various solutes from K. sieversiana were very important

  14. Anditalea andensis ANESC-ST--An Alkaliphilic Halotolerant Bacterium Capable of Electricity Generation under Alkaline-Saline Conditions.

    Directory of Open Access Journals (Sweden)

    Wei Shi

    Full Text Available A great challenge in wastewater bioremediation is the sustained activity of viable microorganisms, which can contribute to the breakdown of waste contaminants, especially in alkaline pH conditions. Identification of extremophiles with bioremediation capability can improve the efficiency of wastewater treatment. Here, we report the discovery of an electrochemically active alkaliphilic halotolerant bacterium, Anditalea andensis ANESC-ST (=CICC10485T=NCCB 100412T, which is capable of generating bioelectricity in alkaline-saline conditions. A. andensis ANESC-ST was shown to grow in alkaline conditions between pH 7.0-11.0 and also under high salt condition (up to 4 wt% NaCl. Electrical output was further demonstrated in microbial fuel cells (MFCs with an average current density of ~0.5 µA/cm2, even under the harsh condition of 4 wt% NaCl and pH 9.0. Subsequent introduction of secreted extracellular metabolites into MFCs inoculated with Escherichia coli or Pseudomonas aeruginosa yielded enhanced electrical output. The ability of A. andensis ANESC-ST to generate energy under alkaline-saline conditions points towards a solution for bioelectricity recovery from alkaline-saline wastewater. This is the first report of A.andensis ANESC-ST producing bioelectricity at high salt concentration and pH.

  15. Experimental and molecular dynamics studies of dysprosium(III) salt solutions for a better representation of the microscopic features used within the binding mean spherical approximation theory.

    Science.gov (United States)

    Ruas, Alexandre; Guilbaud, Philippe; Den Auwer, Christophe; Moulin, Christophe; Simonin, Jean-Pierre; Turq, Pierre; Moisy, Philippe

    2006-10-19

    This work is aimed at a predictive description of the thermodynamic properties of actinide(III) salt solutions at high concentration and 25 degrees C. A new solution of the binding mean spherical approximation (BIMSA) theory, based on the Wertheim formalism, for taking into account 1:1 and also 1:2 complex formation, is used to reproduce, from a simple procedure, experimental osmotic coefficient variation with concentration for three binary salt solutions of the same lanthanide(III) cation: dysprosium(III) perchlorate, nitrate, and chloride. The relevance of the fitted parameters is discussed, and their values are compared with available literature values. UV-vis/near-IR, time-resolved laser-induced fluorescence spectroscopy experiments, and molecular dynamics (MD) calculations were conducted for dilute to concentrated solutions (ca. 3 mol.kg-1) for a study of the microscopic behavior of DyCl3 binary solutions. Coupling MD calculations and extended X-ray absorption fine structure led to the determination of reliable distances. The MD results were used for a discussion of the parameters used in the BIMSA.

  16. Experimental and molecular dynamics studies of dysprosium(III) salt solutions for a better representation of the microscopic features used within the binding mean spherical approximation theory

    Energy Technology Data Exchange (ETDEWEB)

    Ruas, Alexandre; Guilbaud, Philippe; Den Auwer, Christophe; Moulin, Christophe; Simonin, Jean-Pierre; Turq, Pierre; Moisy, Philippe [DEN/DRCP/SCPS, CEA-Valrho Marcoule, BP 17171, 30207 Bagnols-sur-Ceze Cedex, DEN/DPC/SECR/LSRM, CEA-Saclay, Bat 391, BP 91191 Gif sur Yvette, Cedex (France); Laboratoire LI2C (UMR 7612), Universite Pierre et Marie Curie-Paris 6, Boite No. 51, 4 Place Jussieu, 75252 Paris Cedex 05 (France)

    2006-07-01

    This work is aimed at a predictive description of the thermodynamic properties of actinide (III) salt solutions at high concentration and 25 deg. C. A new solution of the binding mean spherical approximation (BIMSA) theory, based on the Wertheim formalism, for taking into account 1: 1 and also 1: 2 complex formation, is used to reproduce, from a simple procedure, experimental osmotic coefficient variation with concentration for three binary salt solutions of the same lanthanide (III) cation: dysprosium (III) perchlorate, nitrate, and chloride. The relevance of the fitted parameters is discussed, and their values are compared with available literature values. UV-vis/near-IR, time-resolved laser-induced fluorescence spectroscopy experiments, and molecular dynamics (MD) calculations were conducted for dilute to concentrated solutions (ca. 3 mol, kg{sup -1}) for a study of the microscopic behavior of DyCl{sub 3} binary solutions. Coupling MD calculations and extended X-ray absorption fine structure led to the determination of reliable distances. The MD results were used for a discussion of the parameters used in the BIMSA. (authors)

  17. Electromembrane recycling of highly mineralized alkaline blowdown water from evaporative water treatment plants at thermal power stations

    Science.gov (United States)

    Chichirova, N. D.; Chichirov, A. A.; Lyapin, A. I.; Minibaev, A. I.; Silov, I. Yu.; Tolmachev, L. I.

    2016-12-01

    Thermal power stations (TPS) are the main source of highly mineralized effluents affecting the environment. An analysis of their water systems demonstrates that alkaline effluents prevail at TPSs. Extraction of an alkali from highly mineralized effluents can make the recycling of effluents economically feasible. A method is proposed of electromembrane recycling of liquid alkaline highly mineralized wastes from TPSs. The process includes electromembrane apparatuses of two types, namely, a diffusion dialysis extractor (DDE) intended for extraction of the alkali from a highly mineralized solution having a complex composition and an electrodialysis concentrator for increasing the concentration of the extracted solution to a value suitable for use in water treatment plants at TPSs. For implementation of the first process (i.e. the extraction of alkali from alkaline-salt solution) various membranes from various manufacturers were studied: CM-PAD and AM-PAD (Ralex, Czechia), MK-40, MA-40, MA-41, MA-414, and MB-2 (OOO OKhK "Shchekinoazot", Russia), AR103-QDF and CR61-CMP (Ionies Inc., USA). The experiments demonstrate that the acceptable degree of separation of the alkali and the salt is achieved in a pair of cation-exchange membranes with the efficiency of separation being higher without an electric field. The highest efficiency was attained with Russian-made membranes (MK-40, OOO OKhK "Shchekinoazot"). A full scale experiment on recycling of highly-mineralized blowdown water from the evaporating water treatment system at the Kazan cogeneration power station No. 3 (TETs-3) was performed in a pilot unit consisting of two electromembrane apparatuses made by UAB "Membraninės Technologijos LT". In the experiments every ton of blowdown water yielded 0.1 t of concentrated alkaline solution with an alkali content of up to 4 wt % and 0.9 t of the softened salt solution suitable for the reuse in the TPS cycle. The power rate is 6 kWh / ton of blowdown water.

  18. Synthesis and uptake of the compatible solutes ectoine and 5-hydroxyectoine by Streptomyces coelicolor A3(2) in response to salt and heat stresses.

    Science.gov (United States)

    Bursy, Jan; Kuhlmann, Anne U; Pittelkow, Marco; Hartmann, Holger; Jebbar, Mohamed; Pierik, Antonio J; Bremer, Erhard

    2008-12-01

    Streptomyces coelicolor A3(2) synthesizes ectoine and 5-hydroxyectoine upon the imposition of either salt (0.5 M NaCl) or heat stress (39 degrees C). The cells produced the highest cellular levels of these compatible solutes when both stress conditions were simultaneously imposed. Protection against either severe salt (1.2 M NaCl) or heat stress (39 degrees C) or a combination of both environmental cues could be accomplished by adding low concentrations (1 mM) of either ectoine or 5-hydroxyectoine to S. coelicolor A3(2) cultures. The best salt and heat stress protection was observed when a mixture of ectoine and 5-hydroxyectoine (0.5 mM each) was provided to the growth medium. Transport assays with radiolabeled ectoine demonstrated that uptake was triggered by either salt or heat stress. The most effective transport and accumulation of [(14)C]ectoine by S. coelicolor A3(2) were achieved when both environmental cues were simultaneously applied. Our results demonstrate that the accumulation of the compatible solutes ectoine and 5-hydroxyectoine allows S. coelicolor A3(2) to fend off the detrimental effects of both high salinity and high temperature on cell physiology. We also characterized the enzyme (EctD) required for the synthesis of 5-hydroxyectoine from ectoine, a hydroxylase of the superfamily of the non-heme-containing iron(II)- and 2-oxoglutarate-dependent dioxygenases (EC 1.14.11). The gene cluster (ectABCD) encoding the enzymes for ectoine and 5-hydroxyectoine biosynthesis can be found in the genome of S. coelicolor A3(2), Streptomyces avermitilis, Streptomyces griseus, Streptomyces scabiei, and Streptomyces chrysomallus, suggesting that these compatible solutes play an important role as stress protectants in the genus Streptomyces.

  19. Condensation of Self-Assembled Lyotropic Chromonic Liquid Crystal Sunset Yellow in Aqueous Solutions Crowded with Polyethylene Glycol and Doped with Salt

    Energy Technology Data Exchange (ETDEWEB)

    Park, Heung-Shik; Kang, Shin-Woong; Tortora, Luana; Kumar, Satyendra; Lavrentovich, Oleg D. (Chonbuk); (Kent)

    2012-10-10

    We use optical and fluorescence microscopy, densitometry, cryo-transmission electron microscopy (cryo-TEM), spectroscopy, and synchrotron X-ray scattering to study the phase behavior of the reversible self-assembled chromonic aggregates of an anionic dye Sunset Yellow (SSY) in aqueous solutions crowded with an electrically neutral polymer polyethylene glycol (PEG) and doped with the salt NaCl. PEG causes the isotropic SSY solutions to condense into a liquid-crystalline region with a high concentration of SSY aggregates, coexisting with a PEG-rich isotropic (I) region. PEG added to the homogeneous nematic (N) phase causes separation into the coexisting N and I domains; the SSY concentration in the N domains is higher than the original concentration of PEG-free N phase. Finally, addition of PEG to the highly concentrated homogeneous N phase causes separation into the coexisting columnar hexagonal (C) phase and I phase. This behavior can be qualitatively explained by the depletion (excluded volume) effects that act at two different levels: at the level of aggregate assembly from monomers and short aggregates and at the level of interaggregate packing. We also show a strong effect of a monovalent salt NaCl on phase diagrams that is different for high and low concentrations of SSY. Upon the addition of salt, dilute I solutions of SSY show appearance of the condensed N domains, but the highly concentrated C phase transforms into a coexisting I and N domains. We suggest that the salt-induced screening of electric charges at the surface of chromonic aggregates leads to two different effects: (a) increase of the scission energy and the contour length of aggregates and (b) decrease of the persistence length of SSY aggregates.

  20. Influence of Proton and Salt Concentration on the Chromonic Liquid Crystal Phase Diagram of Disodium Cromoglycate Solutions: Prospects and Limitations of a Host for DNA Nanostructures.

    Science.gov (United States)

    Zhang, Bingru; Kitzerow, Heinz-S

    2016-03-31

    Lyotropic chromonic liquid crystals have recently been suggested for use as a self-organized host for dispersing and aligning self-organized DNA origami nanostructures. However, an appropriate pH value and a suitable cation concentration are necessary to stabilize such nanostructures and to avoid unfolding of the DNA. The present study shows that the nematic and columnar liquid crystal phases appearing in aqueous solutions of disodium cromoglycate are robust against the replacement of deionized water by a neutral or alkaline buffer solution. However, disodium cromoglycate precipitates when an acidic buffer is used or when the concentration of magnesium cations exceeds a critical concentration of about 0.6-0.7 mmol/L.

  1. The behaviour of salt and salt caverns

    NARCIS (Netherlands)

    Fokker, P.A.

    1995-01-01

    Salts are mined for both storage and extraction purposes, either via dry or solution mining techniques. For operational, environmental and geological purposes, it is important to understand and predict the in situ behaviour of salt, in particular the creep and strength characteristics. A micro-mecha

  2. Efficacy of a solution-based approach for making sodalite waste forms for an oxide reduction salt utilized in the reprocessing of used uranium oxide fuel

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Brian J., E-mail: brian.riley@pnnl.gov [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Pierce, David A. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Frank, Steven M. [Idaho National Laboratory, Idaho Falls, ID 83402 (United States); Matyáš, Josef; Burns, Carolyne A. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States)

    2015-04-15

    This paper describes the various approaches evaluated for making solution-derived sodalite with a LiCl–Li{sub 2}O oxide reduction salt selected to dissolve used uranium oxide fuel so the uranium can be recovered and recycled. The approaches include modified sol–gel and solution-based synthesis processes. As-made products were mixed with 5 and 10 mass% of a Na{sub 2}O–B{sub 2}O{sub 3}–SiO{sub 2} glass binder and these, along with product without a binder, were heated using either a cold-press-and-sinter method or hot uniaxial pressing. The results demonstrate the limitation of sodalite yield due to the fast intermediate reactions between Na{sup +} and Cl{sup −} to form halite in solution and Li{sub 2}O and SiO{sub 2} to form lithium silicates (e.g., Li{sub 2}SiO{sub 3} or Li{sub 2}Si{sub 2}O{sub 5}) in the calcined and sintered pellets. The results show that pellets can be made with high sodalite fractions in the crystalline product (∼92 mass%) and low porosities using a solution-based approach and this LiCl–Li{sub 2}O salt but that the incorporation of Li into the sodalite is low.

  3. Sobre os efeitos vasomotôres exercidos pela agua distilada e pelas soluções anisotonicas de clorêto de sodio Vaso-motricity induced by distilled water and anisotonic salt solutions

    Directory of Open Access Journals (Sweden)

    Antonio Augusto Xavier

    1939-01-01

    Full Text Available The writer reports experiments done with distilled water and hypotonic and hypertonic salt solutions of definite osmotic concentrations. The experiments were performed according to the Laewen-Trendelenburg technic using the vascular system of the frog's hind legs, and according to the Pissemski-Krawkow method using the capillaries of the rabbit's ear. Both preparations react to distilled water by marked vaso-constriction, the same phenomenon taking place in the case of the hypotonic salt solutions. The lower the concentration pf the hypotonic salt solution the stronger the vaso-constriction obtained. With hypertonic salt solutions was observed a strong but rather transient vaso-dilatation followed by secondary vaso-constriction. The later results were found only in the experiments with the frog's hind legs.

  4. Effects of Bile Salt Sodium Glycodeoxycholate on the Self-Assembly of PEO-PPO-PEO Triblock Copolymer P123 in Aqueous Solution.

    Science.gov (United States)

    Bayati, Solmaz; Galantini, Luciano; Knudsen, Kenneth D; Schillén, Karin

    2015-12-22

    A comprehensive experimental study on the interaction between the PEO-PPO-PEO block copolymer P123 (EO20PO68EO20) and the anionic bile salt sodium glycodeoxycholate (NaGDC) in water has been performed. The work was aimed at investigating the suitability of using P123 as bile salt sequestrant beside the fundamental aspects of PEO-PPO-PEO block copolymer-bile salt interactions. Various experimental techniques including dynamic and static light scattering, small-angle X-ray scattering, and differential scanning calorimetry (DSC) were employed in combination with electrophoretic mobility measurements. The system was investigated at a constant P123 concentration of 1.74 mM and with varying bile salt concentrations up to approximately 250 mM NaGDC (or a molar ratio n(NaGDC)/n(P123) = 144). In the mixed P123-NaGDC solutions, the endothermic process related to the self-assembly of P123 was observed to gradually decrease in enthalpy and shift to higher temperatures upon progressive addition of NaGDC. To explain this effect, the formation of NaGDC micelles carrying partly dehydrated P123 unimers was proposed and translated into a stoichiometric model, which was able to fit the experimental DSC data. In the mixtures at low molar ratios, NaGDC monomers associated with the P123 micelle forming a charged "P123 micelle-NaGDC" complex with a dehydrated PPO core. These complexes disintegrated upon increasing NaGDC concentration to form small "NaGDC-P123" complexes visualized as bile salt micelles including one or a few P123 copolymer chains.

  5. The salting-out effect and phase separation in aqueous solutions of tri-sodium citrate and 1-butyl-3-methylimidazolium bromide

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, Rahmat, E-mail: rsadeghi@uok.ac.i [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of); Golabiazar, Roonak [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of); Shekaari, Hemayat [Department of Chemistry, Faculty of Science, University of Mohaghegh Ardabili, Ardabil (Iran, Islamic Republic of)

    2010-04-15

    The aim of this work is to obtain further evidence about the salting-out effect produced by the addition of tri-sodium citrate to aqueous solutions of water miscible ionic liquid 1-butyl-3-methylimidazolium bromide ([C{sub 4}mim][Br]) by evaluating the effect of tri-sodium citrate on the thermodynamic properties of aqueous solutions of this ionic liquid. Experimental measurements of density and sound velocity at different temperatures ranging from (288.15 to 308.15) K, the refractive index at 308.15 K and the liquid-liquid phase diagram at different temperatures ranging from (288.15 to 338.15) K for aqueous solutions containing 1-butyl-3-methylimidazolium bromide ([C{sub 4}mim][Br]) and tri-sodium citrate (Na{sub 3}Cit) are taken. The apparent molar volume of transfer of [C{sub 4}mim][Br] from water to aqueous solutions of Na{sub 3}Cit have positive values and it increases by increasing salt molality. Although at high IL molality, the apparent molar isentropic compressibility shows similar behaviour with that of the apparent molar volume. However at low concentrations of IL, the apparent molar isentropic compressibility of transfer of [C{sub 4}mim][Br] from water to aqueous solutions of Na{sub 3}Cit have negative values. The effects of temperature and the addition of Na{sub 3}Cit and [C{sub 4}mim][Br] on the liquid-liquid phase diagram of the investigated system have been studied. It was found that an increase in temperature caused the expansion of the one-phase region. The presence of Na{sub 3}Cit triggers a salting-out effect, leading to significant upward shifts of the liquid-liquid de-mixing temperatures of the system. The effect of temperature on the phase-forming ability in the system investigated has been studied based on a salting-out coefficient obtained from fitting the binodal values to a Setschenow-type equation for each temperature. Based on cloud point values, the energetics of the clouding process have been estimated and it was found that both of

  6. The Innovative Structure Solution for Preventing Salt Intrusion and Retaining Freshwater In Mekong Delta VietNam

    NARCIS (Netherlands)

    Hong, S.T.; Vrijling, J.K.; Stive, M.J.F.

    2013-01-01

    In the Mekong Delta Vietnam, the construction of sluices with the purpose of retaining fresh water and preventing salt water intrusion potentially plays a very important role. However, the structures constructed in small rivers according to local or traditional technology revealed many disadvantages

  7. Lorentz Force on Sodium and Chlorine Ions in a Salt Water Solution Flow under a Transverse Magnetic Field

    Science.gov (United States)

    De Luca, R.

    2009-01-01

    It is shown that, by applying elementary concepts in electromagnetism and electrochemistry to a system consisting of salt water flowing in a thin rectangular pipe at an average velocity v[subscript A] under the influence of a transverse magnetic field B[subscript 0], an electromotive force generator can be conceived. In fact, the Lorentz force…

  8. A Revisit to the Corrosion Inhibition of Aluminum in Aqueous Alkaline Solutions by Water-Soluble Alginates and Pectates as Anionic Polyelectrolyte Inhibitors

    Directory of Open Access Journals (Sweden)

    Refat Hassan

    2013-01-01

    Full Text Available The corrosion behavior of aluminum (Al in alkaline media in presence of some natural polymer inhibitors has been reinvestigated. The inhibition action of the tested inhibitors was found to obey both Langmuir and Freundlich isotherms models. The inhibition efficiency was found to increase with increasing the inhibitors concentration and decrease with increasing the temperature, suggesting physical adsorption mechanism. Factors such as the concentration and geometrical structure of the inhibitor, concentration of the corrosive medium, and temperature affecting the corrosion rates were examined. The kinetic parameters were evaluated, and a suitable corrosion mechanism consistent with the kinetic results obtained is suggested and discussed.

  9. Efficacy of a Solution-Based Approach for Making Sodalite Waste Forms for an Oxide Reduction Salt Utilized in the Reprocessing of Used Uranium Oxide Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Brian J.; Pierce, David A.; Frank, Steven M.; Matyas, Josef; Burns, Carolyn A.

    2015-04-01

    This paper describes various approaches for making sodalite with a LiCl-Li2O oxide reduction salt used to recover uranium from used oxide fuel. The approaches include sol-gel and solution-based synthesis processes. As-made products were mixed with 5 and 10 mass% of a Na2O-B2O3-SiO2 glass binder and these, along with product without a binder, were heated using either a cold-press-and-sinter method or hot uniaxial pressing. The results demonstrate the limitation of sodalite yield due to the fast intermediate reactions between Na+ and Cl- to form halite in solution and Li2O and SiO2 to form lithium silicates (e.g., Li2SiO3 or Li2Si2O5) in the calcined and sintered pellets. The results show that pellets can be made with high sodalite fractions (~92 mass%) and low porosities using a solution-based approach and this LiCl-Li2O salt.

  10. ELECTROCHEMICAL BEHAVIORS OF ZINC-INDIUM ALLOY ELECTROPLATING IN ALKALINE SOLUTIONS%电镀Zn-In合金在碱性溶液中的电化学行为

    Institute of Scientific and Technical Information of China (English)

    周合兵; 梁曼; 吕东生; 许梦清; 李伟善

    2011-01-01

    用电沉积的方法在Ni基体上制得了Zn-In合金,采用ICP,SEM和EDS研究了电镀Zn-In合金的组织和成分,采用LSV,CV和EIS等方法研究了不同镀时下电镀Zn-In合金在碱性溶液中的电化学行为.结果表明,沉积时间越长,合金中In的含量越高;与镀时为20和30 min相比,10 min为较佳镀时,在此镀时下,Ni基体表面能形成均匀平整的Zn-In合金,延长镀时,会因为局部In颗粒生长过快使Zn-In合金均匀性变差;Zn-In合金中的In能提高Zn电极的析氢过电位,增加Zn阳极溶解电阻,可有效抑制Zn自腐蚀共轭反应的两支;当Zn活化溶解时,In的存在还提供了骨架的作用,为OH-通过合金表面跟内层的Zn反应提供了通道,使得Zn的致钝电位发生正移,活化电位区间也得到拓宽,Zn的钝化得到延缓,放电深度得到加强,放电容量得到提高;Zn的活化溶解产物易于在In电极表面还原,Zn的充放电性能得到改善.%Zinc-indium alloy electrodes based on nickel substrate were prepared by a simple electroplating technique. The content of indium element in zinc-indium alloy became higher with increase in electroplating time. The effects of indium in zinc-indium alloy coating with different electroplating times on the electrochemical behaviors of zinc in alkaline solutions were investigated by inductively coupled ICP, SEM, EDS, LPS, CV and EIS. The results showed that ten minutes was the best electroplating time among the investigated electroplating times. At the plating time of ten minutes, uniform and smooth Zn-In alloy coating could be formed on the surface of nickel substrate. However, as electroplating time went on the uniformity and homogeneity of Zn-In alloy coating became much poorer because of the formation of the local large indium particles resulting from the priority growth. The electrochemical measurements showed that indium in zinc-indium alloy coating could enhance the overpotential of hydrogen evolution and the

  11. Electrostatic self-energy of a partially formed spherical shell in salt solution: application to stability of tethered and fluid shells -- viruses and vesicles

    CERN Document Server

    Bozic, Anze Losdorfer; Podgornik, Rudolf

    2010-01-01

    We investigate the electrostatics of a partially formed, charged spherical shell in a salt solution. We solve the problem numerically at the Poisson-Boltzmann level and analytically in the Debye-Huckel regime. From the results on energetics of partially formed shells we examine the stability of tethered (crystalline) and fluid shells towards rupture. We clearly delineate different regimes of stability towards rupture, where, for fluid shells, we also include the effects of bending elasticity of the shells. Our analysis shows how charging of the shell induces its instability towards rupture but also provides insight regarding growth of charged shells.

  12. Interconnection of salt-induced hydrophobic compaction and secondary structure formation depends on solution conditions: revisiting early events of protein folding at single molecule resolution.

    Science.gov (United States)

    Haldar, Shubhasis; Chattopadhyay, Krishnananda

    2012-03-30

    What happens in the early stage of protein folding remains an interesting unsolved problem. Rapid kinetics measurements with cytochrome c using submillisecond continuous flow mixing devices suggest simultaneous formation of a compact collapsed state and secondary structure. These data seem to indicate that collapse formation is guided by specific short and long range interactions (heteropolymer collapse). A contrasting interpretation also has been proposed, which suggests that the collapse formation is rapid, nonspecific, and a trivial solvent related compaction, which could as well be observed by a homopolymer (homopolymer collapse). We address this controversy using fluorescence correlation spectroscopy (FCS), which enables us to monitor the salt-induced compaction accompanying collapse formation and the associated time constant directly at single molecule resolution. In addition, we follow the formation of secondary structure using far UV CD. The data presented here suggest that both these models (homopolymer and heteropolymer) could be applicable depending on the solution conditions. For example, the formation of secondary structure and compact state is not simultaneous in aqueous buffer. In aqueous buffer, formation of the compact state occurs through a two-state co-operative transition following heteropolymer formalism, whereas secondary structure formation takes place gradually. In contrast, in the presence of urea, a compaction of the protein radius occurs gradually over an extended range of salt concentration following homopolymer formalism. The salt-induced compaction and the formation of secondary structure take place simultaneously in the presence of urea.

  13. Etch Figure on a Garnet Crystal Formed by Alkaline Reagents and Its Difference from That Formed by Acid Solution%石榴子石晶体碱腐蚀像及其与酸腐蚀像的对比

    Institute of Scientific and Technical Information of China (English)

    刘河清; 赵珊茸; 徐畅; 李坤

    2011-01-01

    In this paper, NaOH-KOH mixture of melt and KOH solution were used to corrode a garnet crystal. The etch figures on faces (or sections) with different crystallographic directions were observed, and a stereographic model of etch figures were established. The difference between the etch figures formed by HF solution and alkaline reagents on the same crystal face or section was also analyzed. It is indicated that both alkaline etching and acid etching can reflect the characteristics of the crystal symmetry. Comparison shows that alkaline etching figure is the same as acid etching figure on { 100 } and {110} , but alkaline etching figure is different from acid etching figure on { 120} , {221}、{ 111} and {211}. The study can be used for the crystallography orientation of garnet group minerals, and it is also be used to reveal the pH geological environment for garnet formation.%本文采用NaOH-KOH混合熔融物和KOH溶液对石榴子石晶体各种不同的结晶学方向的晶面(切面)进行腐蚀实验,建立了石榴子石碱腐蚀像的立体模型,并与酸(HF溶液)腐蚀像模型进行对比.研究发现碱腐蚀像与酸腐蚀像一样能很好的反映晶体的对称特点,并发现在{ 100}、{110}晶面(切面)上碱腐蚀像与酸腐蚀像相同,而在{120}、{221}、{111}、{211}晶面(切面)上,碱腐蚀像与酸腐蚀像不同.该研究可以用来对石榴子石族矿物进行结晶学定向,同时具有揭示矿物所处地质环境酸碱性的指示意义.

  14. Dynamics of the separation of amino acid and mineral salt in the stationary dialysis of solutions with an MK-40 profiled sulfo group cation exchange membrane

    Science.gov (United States)

    Vasil'eva, V. I.; Vorob'eva, E. A.

    2012-11-01

    The conjugated diffusion transport of amino acid and mineral salt through a profiled sulfo group cation exchange membrane that simulates the extraction of amino acid from wash waters of microbiological production containing mineral components not used in synthesis is studied. The competitive nature of the conjugation of flows resulting in a decrease in the rate of the mass transfer of components and their separation factor is established from a comparative analysis of experimental data on the diffusion transfer of phenylalanine and sodium chloride in the form of hydrogen from individual and mixed solutions through a profiled sulfo group cation exchange membrane. The range of concentrations and the ratio of components in solution corresponding to the effective separation of phenylalanine and sodium chloride are determined.

  15. Application of extraction chromatography to the separation of thorium and uranium dissolved in a solution of high salt concentration.

    Science.gov (United States)

    Fujiwara, Asako; Kameo, Yutaka; Hoshi, Akiko; Haraga, Tomoko; Nakashima, Mikio

    2007-01-26

    Extraction chromatography with commercially available UTEVA resin (for uranium and tetravalent actinide) was applied for the separation of Th and U from control solutions prepared from a multi-element control solution and from sample solutions of solidified simulated waste. Thorium and U in control solutions with 1-5mol/dm(3) HNO(3) were extracted with UTEVA resin and recovered with a solution containing 0.1mol/dm(3) HNO(3) and 0.05mol/dm(3) oxalic acid to be separated from the other metallic elements. Extraction behavior of U in the sample solutions was similar to that in the control solutions, but extraction of Th was dependent on the concentration of HNO(3). Thorium was extracted from 5mol/dm(3) HNO(3) sample solutions but not from 1mol/dm(3) HNO(3) sample solutions. We conjecture that thorium fluoride formation interferes with extraction of Th. Addition of Al(NO(3))(3) and Fe(NO(3))(3), which have higher stability constant with fluoride ion than Th, does improve extractability of Th from 1mol/dm(3) HNO(3) sample solution.

  16. Evaluation of layered zinc hydroxide nitrate and zinc/nickel double hydroxide salts in the removal of chromate ions from solutions

    Science.gov (United States)

    de Oliveira, Henrique Bortolaz; Wypych, Fernando

    2016-11-01

    Layered zinc hydroxide nitrate (ZnHN) and Zn/Ni layered double hydroxide salts were synthesized and used to remove chromate ions from solutions at pH 8.0. The materials were characterized by many instrumental techniques before and after chromate ion removal. ZnHN decomposed after contact with the chromate solution, whereas the layered structure of Zn/Ni hydroxide nitrate (Zn/NiHN) and Zn/Ni hydroxide acetate (Zn/NiHA) remained their layers intact after the topotactic anionic exchange reaction, only changing the basal distances. ZnHN, Zn/NiHN, and Zn/NiHA removed 210.1, 144.8, and 170.1 mg of CrO42-/g of material, respectively. Although the removal values obtained for Zn/NiHN and Zn/NiHA were smaller than the values predicted for the ideal formulas of the solids (194.3 and 192.4 mg of CrO42-/g of material, respectively), the measured capacities were higher than the values achieved with many materials reported in the literature. Kinetic experiments showed the removal reaction was fast. To facilitate the solid/liquid separation process after chromium removal, Zn/Ni layered double hydroxide salts with magnetic supports were also synthesized, and their ability to remove chromate was evaluated.

  17. Specific Na+ and K+ Cation Effects on the Interfacial Water Molecules at the Air/Aqueous Salt Solution Interfaces Probed with Non-resonant Second Harmonic Generation (SHG)

    CERN Document Server

    Bian, Hong-tao; Guo, Yuan; Wang, Hong-fei

    2008-01-01

    Here we report the polarization dependent non-resonant second harmonic generation (SHG) measurement of the interfacial water molecules at the aqueous solution of the following salts: NaF, NaCl, NaBr, KF, KCl, and KBr. Through quantitative polarization analysis of the SHG data,the orientational parameter D value and the relative surface density of the interfacial water molecules at these aqueous solution surfaces were determined. From these results we found that addition of each of the six salts caused increase of the thickness of the interfacial water layer at the surfaces to a certain extent. Noticeably, both the cations and the anions contributed to the changes, and the abilities to increase the thickness of the interfacial water layer were in the following order: KBr > NaBr > KCl > NaCl ~ NaF > KF. Since these changes can not be factorized into individual anion and cation contributions, there are possible ion pairing or association effects, especially for the NaF case. We also found that the orientational ...

  18. Effects of Na2SO4 or NaCl on sonochemical degradation of phenolic compounds in an aqueous solution under Ar: Positive and negative effects induced by the presence of salts.

    Science.gov (United States)

    Uddin, Md Helal; Nanzai, Ben; Okitsu, Kenji

    2016-01-01

    Sonochemical degradation of 4-chlorophenol, phenol, catechol and resorcinol was studied under Ar at 200 kHz in the absence and presence of Na2SO4 or NaCl. The rates of sonochemical degradation in the absence of salts decreased in the order 4-chlorophenol>phenol>catechol>resorcinol and this order was in good agreement with the order of log P (partition coefficient) value of each phenolic compound. The effects of salts on the rates of sonochemical degradation consisted of no effect or slight negative or positive effects. We discussed these unclear results based on two viewpoints: one was based on the changes in pseudo hydrophobicity and/or diffusion behavior of phenolic compounds and the other was based on the changes in solubility of Ar gas. The measured log P value of each phenolic compound slightly increased with increasing salt concentration. In addition, the dynamic surface tension for 4-chlorophenol aqueous solution in the absence and presence of Na2SO4 or NaCl suggested that phenolic compounds more easily accumulated at the interface region of bubbles at higher salt concentration. These results indicated that the rates of sonochemical degradation should be enhanced by the addition of salts. On the other hand, the calculated Ar gas solubility was confirmed to decrease with increasing salt concentration. The yield of H2O2 formed in the presence of Na2SO4 or NaCl decreased with increasing salt concentration. These results suggested that sonochemical efficiency decreased with decreasing gas amount in aqueous solution: a negative effect of salts was observed. Because negative and positive effects were induced simultaneously, we concluded that the effects of salts on the rates of sonochemical degradation of phenolic compounds became unclear. The products formed from sonochemical degradation of 4-chlorophenol were also characterized by HPLC analysis. The formation of phenol and 4-chloro-1,3-dihydroxy benzene was confirmed and these concentrations were affected by the

  19. Electrochemical characterization of the LiCoO{sub 2}/acetylene carbon ratios for porous electrodes in alkaline lithium aqueous solutions by electrochemical impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Castaneda, H., E-mail: castanedah@battelle.or [Battelle Memorial Institute, 505 King Avenue, Columbus OH, 43201 (United States); Tan, B.; Saunders, J. [Battelle Memorial Institute, 505 King Avenue, Columbus OH, 43201 (United States)

    2010-05-01

    LiCoO{sub 2} electrodes were fabricated with different acetylene carbon (AC) additions and fixed binder content. Subsequent electrochemical testing showed different processes at the interface that are related to pore distribution and electrode composition. Electrochemical impedance spectroscopy characterized the mechanisms close to open circuit conditions. The active state, combined with diffusion mechanisms within the cylindrical pores, contributed to the functionality of the particles according to the LiCoO{sub 2}/AC content, and surface characteristics of the electrode influenced the impedance distribution. The de Levie theory for porous electrode was used to describe the influence of the LiCoO{sub 2}/AC ratios in the impedance distribution when exposed to alkaline aqueous electrolytes (LiOH + Li{sub 2}SO{sub 4}). The pore model helped relate physical properties of the composite material, such as pore count, pore length, and double layer capacitance, with the mechanisms present at the interface. The theoretical model was validated with experimental data and the fitting process resulted in good agreement.

  20. Electrochemical behaviour of alkaline copper complexes

    Indian Academy of Sciences (India)

    C L Aravinda; S M Mayanna; V R Muralidharan

    2000-10-01

    A search for non-cyanide plating baths for copper resulted in the development of alkaline copper complex baths containing trisodium citrate [TSC] and triethanolamine [TEA]. Voltammetric studies were carried out on platinum to understand the electrochemical behaviour of these complexes. In TSC solutions, the deposition of copper involves the slow formation of a monovalent species. Adsorption of this species obeys Langmuir isotherm. In TEA solutions the deposition involves the formation of monovalent ions obeying the non-activated Temkin isotherm. Conversion of divalent to monovalent copper is also slow. In TEA and TSC alkaline copper solutions, the predominant species that undergo stepwise reduction contain only TEA ligands

  1. Oxidation catalysts on alkaline earth supports

    Energy Technology Data Exchange (ETDEWEB)

    Mohajeri, Nahid

    2017-03-21

    An oxidation catalyst includes a support including particles of an alkaline earth salt, and first particles including a palladium compound on the support. The oxidation catalyst can also include precious metal group (PMG) metal particles in addition to the first particles intermixed together on the support. A gas permeable polymer that provides a continuous phase can completely encapsulate the particles and the support. The oxidation catalyst may be used as a gas sensor, where the first particles are chemochromic particles.

  2. α-Cyclodextrin/aminobenzoic acid binding in salt solutions at different pH: dependence on guest structure.

    Science.gov (United States)

    Romanova, Anastasia; Chibunova, Ekaterina; Kumeev, Roman; Fedorov, Maxim; Terekhova, Irina

    2013-06-01

    Influence of Na(+) and K(+) cations on α-cyclodextrin guest-host complex formation with isomeric aminobenzoic acids was examined at different pH and temperature of 298.15 K by (1)H NMR and calorimetry methods. More pronounced influence of Na(+) on inclusion complex formation of α-CD with aminobenzoic acid anions compare to the effects of Na(+) on α-CD complex formation with zwitterionic aminobenzoic acid molecules was revealed. For the first time, the dependence of salt effects on the structure, ionization and the hydration state of the guest molecule was demonstrated and analysed on the basis of the obtained thermodynamic parameters of complex formation and calculated free energy of hydration of different ionized forms of aminobenzoic acids.

  3. Effects of Interfacial Reaction on the Radial Displacement of Oil by Alkaline Solutions Effets des réactions interfaciales sur le déplacement radial de l'huile par les solutions alcalines

    Directory of Open Access Journals (Sweden)

    Nasr-El-Din H. A.

    2006-11-01

    Full Text Available Caustic flooding is frequently used to recover acidic oils in secondary and tertiary recovery modes. This study examines the secondary recovery of an acidic oil by alkaline solutions in a water-wet porous medium using a radial geometry. A model porous medium consisting of sintered glass beads sandwiched between two glass plates was employed to visualize the displacement process. The medium was originally saturated with the oil phase, namely paraffin oil (non-reacting system or paraffin oil doped with 1 wt% linoleic acid (reacting system. The effects of the injection flow rate and the NaOH concentration in the aqueous phase on the displacement pattern were studied experimentally. The volumetric oil recovery at the breakthrough condition was also measured. Dynamic interfacial tension (IFT measurements for the reacting system were measured in a spinning drop tensiometer. A drastic drop in the IFT occurred as a result of the chemical reaction at the interface between the linoleic acid in the oil phase and the NaOH in the aqueous phase. It was also found that the IFT behavior with respect to time was a function of NaOH concentration with a maximum interfacial activity (minimum IFT occurring at 0. 1 w% NaOH. Displacement runs showed a significant change in the displacement patterns during secondary recovery for the reacting system compared with those for the non-reacting one. A significant drop in the breakthrough recovery was obtained for the reacting systems, especially at high injection flow rates. The breakthrough recovery of the reacting system was found to be a function of NaOH concentration in the aqueous phase, with a minimum recovery at NaOH concentration of 0. 1 wt%. On a souvent recours à la submersion par des produits alcalins pour récupérer les acides gras dans les modes secondaire et tertiaire. Dans cette étude, on examine la récupération secondaire d'un acide gras par des solutions alcalines dans un milieu poreux imprégné d

  4. Evaluation of p-phenylenediamine, o-phenylphenol sodium salt, and 2,4-diaminotoluene in the rat comet assay as part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiated international validation study of in vivo rat alkaline comet assay.

    Science.gov (United States)

    De Boeck, Marlies; van der Leede, Bas-jan; De Vlieger, Kathleen; Geys, Helena; Vynckier, An; Van Gompel, Jacky

    2015-07-01

    As part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiated international validation study of in vivo rat alkaline comet assay (comet assay), p-phenylenediamine dihydrochloride (PPD), o-phenylphenol sodium salt (OPP), and 2,4-diaminotoluene (2,4-DAT), were analyzed in this laboratory as coded test chemicals. Male Sprague-Dawley rats (7-9 weeks of age) were given three oral doses of the test compounds, 24 and 21 h apart and liver and stomach were sampled 3h after the final dose administration. Under the conditions of the test, no increases in DNA damage were observed in liver and stomach with PPD and OPP up to 100 and 1000 mg/kg/day, respectively. 2,4-DAT, a known genotoxic carcinogen, induced a weak but reproducible, dose-related and statistically significant increase in DNA damage in liver cells while no increases were observed in stomach cells.

  5. Electro-hydrodynamic generation of monodisperse nanoparticles in the sub-10 nm size range from strongly electrolytic salt solutions: governing parameters of scaling laws

    Energy Technology Data Exchange (ETDEWEB)

    Maisser, Anne, E-mail: a.maisser@tudelft.nl [Delft University of Technology (Netherlands); Attoui, Michel B. [LISA, UMR CNRS University Paris Est Creteil, University Paris-Diderot (France); Ganan-Calvo, Alfonso M. [Universidad de Sevilla, ESI (Spain); Szymanski, Wladyslaw W. [University of Vienna, Faculty of Physics (Austria)

    2013-01-15

    A charge reduced electro-hydrodynamic atomization (EHDA) device has been used to generate airborne salt clusters in the sub 10 nm size range. The focus of this study on that specific sub-micron range of electrospray droplets with relatively high electrical conductivities and permittivities aims to address the still existing controversy on the scaling laws of electrosprayed droplet diameters. In this study different concentrations of sodium chloride and potassium chloride-both show strong electrolytic behavior-have been electrosprayed from solutions in pure water, or from aqueous ammonium acetate buffer liquids of varying concentrations. The dry residue salt cluster diameter generated by the EHDA process have been measured using a differential mobility analyzer. The initial droplet diameter has been determined indirectly from the measured particle size following the steps of Chen et al. (J Aerosol Sci 26:963-977, 1995). Results have been compared to existing scaling laws valid for direct droplet measurements. They can be interpreted concisely on the basis of a realistic hypothesis on possible electrochemical effects taking place and affecting the droplet and thus nanoparticle formation in EHDA. The hypothesis developed in this work and the comparison with the experimental results are shown and discussed in the manuscript.

  6. QM/MM analysis suggests that Alkaline Phosphatase (AP) and Nucleotide pyrophosphatase/phosphodiesterase slightly tighten the transition state for phosphate diester hydrolysis relative to solution: implication for catalytic promiscuity in the AP superfamily

    Science.gov (United States)

    Hou, Guanhua

    2011-01-01

    Several members of the Alkaline Phosphatase (AP) superfamily exhibit a high level of catalytic proficiency and promiscuity in structurally similar active sites. A thorough characterization of the nature of transition state for different substrates in these enzymes is crucial for understanding the molecular mechanisms that govern those remarkable catalytic properties. In this work, we study the hydrolysis of a phosphate diester, MpNPP−, in solution, two experimentally well-characterized variants of AP (R166S AP, R166S/E322Y AP) and wild type Nucleotide pyrophosphatase/phosphodiesterase (NPP) by QM/MM calculations in which the QM method is an approximate density functional theory previously parameterized for phosphate hydrolysis (SCC-DFTBPR). The general agreements found between these calculations and available experimental data for both solution and enzymes support the use of SCC-DFTBPR/MM for a semi-quantitative analysis of the catalytic mechanism and nature of transition state in AP and NPP. Although phosphate diesters are cognate substrates for NPP but promiscuous substrates for AP, the calculations suggest that their hydrolysis reactions catalyzed by AP and NPP feature similar synchronous transition states that are slightly tighter in nature compared to that in solution, due in part to the geometry of the bimetallic zinc motif. Therefore, this study provides the first direct computational support to the hypothesis that enzymes in the AP superfamily catalyze cognate and promiscuous substrates via similar transition states to those in solution. Our calculations do not support the finding of recent QM/MM studies by López-Canut and coworkers, who suggested that the same diester substrate goes through a much looser transition state in NPP/AP than in solution, a result likely biased by the large structural distortion of the bimetallic zinc site in their simulations. Finally, our calculations for different phosphate diester orientations and phosphorothioate diesters

  7. The study of the process of alkaline precipitation purification of solutions from silicon macroscales in the ammonium-fluoride processing of beryllium-containing materials

    Directory of Open Access Journals (Sweden)

    Dyachenko Alexander

    2016-01-01

    Full Text Available The ammonium-fluoride method of beryllium materials processing is examined. An analysis of the existing sulfuric-acid and fluoride processing scheme of beryllium-containing concentrates processing is described; advantages of the proposed ammonium-fluoride scheme and possible problems that may occur when testing a new technique are discussed. Studies on determining the effect of silicon macroscales on the behavior of beryllium in fluoride solutions at an increased pH, as well as on establishing the distribution of beryllium and silicon by phases in laboratory testing of the technology on model mixtures, are described. As a result of the studies, it is found that precipitation purification of solutions from silicon with a solution of ammonia is possible at a temperature of 20-25 °C. The paper presents data on the effect of an excessive concentration of ion-fluoride in a solution on the pH level of silicon precipitation; and on the hydrolysis degree of beryllium and silicon during the precipitation.

  8. Effects of Amendment of Biochar and Pyroligneous Solution from wheat straw pyrolysis on Yield and soil and crop salinity in a Salt stressed cropland from Central China Great Plain

    Science.gov (United States)

    Li, L.; Liu, Y.; Pan, W.; Pan, G.; Zheng, J.; Zheng, J.; Zhang, X.

    2012-04-01

    Crop production has been subject to salt stress in large areas of world croplands. Organic and/or bio-fertilizers have been applied as soil amendments for alleviating salt stress and enhancing crop productivity in these salt-stressed croplands. While biochar production systems using pyrolysis of crop straw materials have been well developed in the world, there would be a potential measure to use materials from crop straw pyrolysis as organic amendments in depressing salt stress in agriculture. In this paper, a field experiment was conducted on the effect of biochar and pyroligneous solution from cropstraw pyrolysis on soil and crop salinity, and wheat yield in a moderately salt stressed Entisol from the Central Great Plain of North China. Results indicated that: biochar and pyroligneous solution increased soil SOC, total nitrogen, available potassium and phosphorous by 43.77%, 6.50%, 45.54% and 108.01%, respectively. While Soil bulk density was decreased from 1.30 to 1.21g cm-3; soil pH (H2O) was decreased from 8.23 to 7.94 with a decrease in soluble salt content by 38.87%. Wheat yield was doubled over the control without amendment. In addition, sodium content was sharply declined by 78.80% in grains, and by 70.20% and 67.00% in shoot and root, respectively. Meanwhile, contents of potassium and phosphorus in plant tissue were seen also increased despite of no change in N content. Therefore, the combined amendment of biochar with pyroligneous solution would offer an effective measure to alleviate the salt stress and improving crop productivity in world croplands. Keywords: biochar, salt affected soils, wheat, crop productivity, salinity

  9. Data on energy-band-gap characteristics of composite nanoparticles obtained by modification of the amorphous potassium polytitanate in aqueous solutions of transition metal salts

    Directory of Open Access Journals (Sweden)

    D.A. Zimnyakov

    2016-06-01

    Full Text Available Here we present the data on the energy-band-gap characteristics of composite nanoparticles produced by modification of the amorphous potassium polytitanate in aqueous solutions of different transition metal salts. Band gap characteristics are investigated using diffuse reflection spectra of the obtained powders. Calculated logarithmic derivative quantity of the Kubelka–Munk function reveals a presence of local maxima in the regions 0.5–1.5 eV and 1.6–3.0 eV which correspond to band gap values of the investigated materials. The values might be related to the constituents of the composite nanoparticles and intermediate products of their chemical interaction.

  10. Characteristic of the Nanoparticles Formed on the Carbon Steel Surface Contacting with 3d-Metal Water Salt Solutions in the Open-Air System

    Science.gov (United States)

    Lavrynenko, O. M.; Pavlenko, O. Yu; Shchukin, Yu S.

    2016-02-01

    The contact of a steel electrode with water dispersion medium in an open-air system leads to the development of various polymorphic iron oxides and oxyhydroxides on the steel surface. Whereas the usage of distilled water causes the obtaining of Fe(II)-Fe(III) layered double hydroxides (green rust) as a primary mineral phase, but in the presence of inorganic 3d-metal water salt solutions, mixed layered double hydroxides (LDHs) together with non-stoichiometric spinel ferrite nanoparticles are formed on the steel surface. Mixed LDHs keep stability against further oxidation and complicate the obtaining of spinel ferrite nanoparticles. Thermal treatment of mixed LDHs among other mineral phases formed via the rotation-corrosion dispergation process at certain temperatures permits to obtain homogenous nanoparticles of spinel ferrites as well as maghemite or hematite doped by 3d-metal cations.

  11. Cost-effective electrostatic-sprayed SrAl2O4:Eu2+ phosphor coatings by using salted sol–gel derived solution

    Indian Academy of Sciences (India)

    Kyu-Seog Hwang; Bo-An Kang; Sung-Dai Kim; Seung Hwangbo; Jim-Tae Kim

    2011-08-01

    3 Mol% of europium doped strontium aluminate (SrAl2O4:Eu2+) coatings on silicon substrates were prepared by electrostatic spray deposition method using a salted sol–gel derived solution as a starting material. Asdeposited films at 100°C for 5 h were heated at 1100°C for 2 h under a reducing ambient atmosphere of 95%N2 + 5%H2 . Nanocrystalline SrAl2O4 film was confirmed by surface morphological and crystallographic analyses. Monitored at 520 nm, the excitation spectrum showed a broad band from 300 ∼ 500 nm and the emission intensity showed a maximum yellow peak intensity at 512 nm with a broad band from 460 ∼ 610 nm.

  12. Study of electrical conductivity response upon formation of ice and gas hydrates from salt solutions by a second generation high pressure electrical conductivity probe.

    Science.gov (United States)

    Sowa, Barbara; Zhang, Xue Hua; Kozielski, Karen A; Dunstan, Dave E; Hartley, Patrick G; Maeda, Nobuo

    2014-11-01

    We recently reported the development of a high pressure electrical conductivity probe (HP-ECP) for experimental studies of formation of gas hydrates from electrolytes. The onset of the formation of methane-propane mixed gas hydrate from salt solutions was marked by a temporary upward spike in the electrical conductivity. To further understand hydrate formation a second generation of window-less HP-ECP (MkII), which has a much smaller heat capacity than the earlier version and allows access to faster cooling rates, has been constructed. Using the HP-ECP (MkII) the electrical conductivity signal responses of NaCl solutions upon the formation of ice, tetrahydrofuran hydrates, and methane-propane mixed gas hydrate has been measured. The concentration range of the NaCl solutions was from 1 mM to 3M and the driving AC frequency range was from 25 Hz to 5 kHz. This data has been used to construct an "electrical conductivity response phase diagrams" that summarize the electrical conductivity response signal upon solid formation in these systems. The general trend is that gas hydrate formation is marked by an upward spike in the conductivity at high concentrations and by a drop at low concentrations. This work shows that HP-ECP can be applied in automated measurements of hydrate formation probability distributions of optically opaque samples using the conductivity response signals as a trigger.

  13. A New Attempt at Alkaline Texturization of Monocrystaline Silicon with Anionic Surfactant as the Additive

    Science.gov (United States)

    Li, Hailing; Wang, Wenjing; Zhao, Lei; Zhou, Chunlan; Diao, Hongwei

    2012-10-01

    Owing to the volatilization of isopropanol (IPA), instability in the alkaline texturization of monocrystalline silicon has been a big problem for a long time. Many additives were adapted to replace IPA, such as high boiling point alcohols. In this experiment, as a new attempt, sodium lauryl sulfate (SDS), a type of anionic surfactant, was used as the additive in NaOH solution. The etching properties of silicon in 2 wt % NaOH/15-30 mg/L SDS solution were analyzed. To improve the wettability of silicon, two types of metal salt, NaCl and Na2CO3 with concentration from 2 to 15 wt %, were applied to the 2 wt % NaOH/15 mg/L SDS solution. The results showed that the effect of NaCl was better than that of Na2CO3. Finally, the role of the additive was discussed.

  14. Behavioral and neural responses of toads to salt solutions correlate with basolateral membrane potential of epidermal cells of the skin

    DEFF Research Database (Denmark)

    Hillyard, Stanley D; Baula, Victor; Tuttle, Wendy

    2007-01-01

    Dehydrated toads initiated water absorption response (WR) behavior and absorbed water from dilute NaCl solutions. With 200-250 mM NaCl, WR behavior and water absorption were both suppressed. With 200-250 mM Na-gluconate, WR initiation was significantly greater than with NaCl but water loss was gr...

  15. Summary technical report on the electrochemical treatment of alkaline nuclear wastes

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, D.T.

    1994-07-30

    This report summarizes the laboratory studies investigating the electrolytic treatment of alkaline solutions carried out under the direction of the Savannah River Technology Center from 1985-1992. Electrolytic treatment has been demonstrated at the laboratory scale to be feasible for the destruction of nitrate and nitrite and the removal of radioactive species such as {sup 99}Tc and {sup 106}Ru from Savannah River Site (SRS) decontaminated salt solution and other alkaline wastes. The reaction rate and current efficiency for the removal of these species are dependent on cell configuration, electrode material, nature of electrode surface, waste composition, current density, and temperature. Nitrogen, ammonia, and nitrous oxide have been identified as the nitrogen-containing reaction products from the electrochemical reduction of nitrate and nitrite under alkaline conditions. The reaction mechanism for the reduction is very complex. Voltammetric studies indicated that the electrode reactions involve surface phenomena and are not necessarily mass transfer controlled. In an undivided cell, results suggest an electrocatalytic role for oxygen via the generation of the superoxide anion. In general, more efficient reduction of nitrite and nitrate occurs at cathode materials with higher overpotentials for hydrogen evolution. Nitrate and nitrite destruction has also been demonstrated in engineering-scale flow reactors. In flow reactors, the nitrate/nitrite destruction efficiency is improved with an increase in the current density, temperature, and when the cell is operated in a divided cell configuration. Nafion{reg_sign} cation exchange membranes have exhibited good stability and consistent performance as separators in the divided-cell tests. The membranes were also shown to be unaffected by radiation at doses approximating four years of cell operation in treating decontaminated salt solution.

  16. Separation characteristics of rare earth elements in the TOPO/DTPA - Salting-out reagent solution system

    Energy Technology Data Exchange (ETDEWEB)

    Miyahara, S.; Koma, Yoshikazu; Koyama, Tomozo; Tanaka, Yasumasa [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan). Tokai Works; Kano, J.

    1998-11-01

    A test of mutual separation of rare earth elements was carried out using an organic phosphorus extraction solvent TOPO (tri-octyl phosphorus oxide). It was found that the distribution ratio monotonously increased with the atomic number and the separation factor of La/Ln was 10{sup 3}. Under the condition that a sufficient quantity of DTPA compared with the amount of rare earth metals and pH > 1.5 in which DTPA easily formed complexes with lanthanides, the following conclusions were obtained; (i) the separation factor was not affected by pH, the kind of salting-out reagent, or the concentration, (ii) the extraction reaction with TOPO and complex formation with DTPA mainly contributed to the separation of lanthanides, and (iii) the separation factor computed by means of the distribution ratio of TOPO extraction and complex formation constant for DTPA more or less agreed with the empirical value. Separation of rare earth elements using TOPO revealed similar characteristics to those of systems with CMPO and TBP. (H. Baba)

  17. Effect of nickel content on the anodic dissolution and passivation of zinc–nickel alloys in alkaline solutions by potentiodynamic and potentiostatic techniques

    Indian Academy of Sciences (India)

    Abdel-Rahman El-Sayed; Hany M Abd El-Lateef; Hossnia S Mohran

    2015-04-01

    The effect of systematic increase of Ni on the anodic dissolution and passivation of Zn–Ni alloys in various concentrations of KOH solution (0.1–1 M) was investigated. The anodic dissolution and passivation behaviour for each pure Zn and Ni in the same studied solutions was also investigated, and the obtained data were compared. Potentiodynamic and potentiostatic methods were used, and the corrosion layer formed on each electrode surface was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results of the anodic potentiodynamic measurements exhibited that the polarization curves showed active/passive transition in the case of Ni and active/pseudopassive in the case of both Zn and its alloys. The results showed that the increase in Ni content increases the activation energy (a) and decreases the dissolution rate of the alloys in KOH solution, and the lowest dissolution rate was obtained at 10% Ni. The results of both potentiodynamic and potentiostatic measurements exhibit sudden increase in current density which is observed at certain positive potential (+0.42 V .SCE) in the case of the investigated alloys. This indicates that the addition of Ni to Zn promotes the electrochemical reaction (in the passive region). However, the passivation potential shifted to more positive direction with the increase in Ni content in the alloy.

  18. Anodes for alkaline electrolysis

    Science.gov (United States)

    Soloveichik, Grigorii Lev

    2011-02-01

    A method of making an anode for alkaline electrolysis cells includes adsorption of precursor material on a carbonaceous material, conversion of the precursor material to hydroxide form and conversion of precursor material from hydroxide form to oxy-hydroxide form within the alkaline electrolysis cell.

  19. Studies on Fast Remediation of Soda Meadow Alkaline Soil

    Institute of Scientific and Technical Information of China (English)

    ZHOU Lianren; SUN Yankun; LI Dawei

    2010-01-01

    Researches on models of remediation quickly in soda meadow alkaline soil, and dynamic variation of water-salt in saline soil of Zhaozhou County were studied systematically from 2001 to 2006. Realize the vegetation cover of those years through the artificial planting, mixed seeding lymc grass (Elymus dahuricus Turcz) and melilot in the mode of rotary tillage and deep loosening in lower and medium saline soils. The results showed that there was remarkable relationship between net evaporation (difference of precipitation and evaporation) and total salt content in the soil. The net evaporation could be used as a new method to forecast the dynamics variation of salt to ensure the pasture optimum sowing time. Realize the autumnal vegetation cover of those years through direct planting on the bourgeon layer of soda meadow alkaline soil, on the other hand, the covered pasture made the function of restraining salt and alkaline content to realize the biology reverse succession quickly. Forage seeds were seeded directly on the seeding bed of soda alkaline meadow at the end of July. In fall of the same year, a certain amount of biomass was obtained. The model, which has remarkable economical efficiency and use widely, represented the innovative model for the fast vegetation restoration on the soda alkaline meadow soil.

  20. A scanning tunneling microscopy investigation of the phases formed by the sulfur adsorption on Au(100) from an alkaline solution of 1,4-piperazine(bis)-dithiocarbamate of potassium

    Energy Technology Data Exchange (ETDEWEB)

    Martínez, Javier A. [Instituto de Ciencia y Tecnología de Materiales (IMRE), Universidad de La Habana, Zapata y G, El Vedado, Plaza de la Revolución, La Habana 10400 (Cuba); Valenzuela B, José [Centro de Nanociencias y Nanotecnología (CNyN), Universidad Nacional Autónoma de México (UNAM) , km 107 Carretera Tijuana-Ensenada, Ensenada, BC 22860 (Mexico); Cao Milán, R. [Facultad de Química, Universidad de La Habana, Zapata y G, El Vedado, Plaza de la Revolución, La Habana 10400 (Cuba); Herrera, José [Instituto de Ciencia y Tecnología de Materiales (IMRE), Universidad de La Habana, Zapata y G, El Vedado, Plaza de la Revolución, La Habana 10400 (Cuba); Farías, Mario H. [Centro de Nanociencias y Nanotecnología (CNyN), Universidad Nacional Autónoma de México (UNAM) , km 107 Carretera Tijuana-Ensenada, Ensenada, BC 22860 (Mexico); Hernández, Mayra P., E-mail: mayrap@fisica.uh.cu [Instituto de Ciencia y Tecnología de Materiales (IMRE), Universidad de La Habana, Zapata y G, El Vedado, Plaza de la Revolución, La Habana 10400 (Cuba)

    2014-11-30

    Highlights: • New phases of sulfur on gold: hexamer and (√(2)×√(2)) were observed by STM. • Hexamers and (√(2)×√(2)) structures coexist with well-known octomers. • Formation of sulfur multilayer by K{sub 2}DTC{sub 2}pz hydrolysis under alkaline condition. • Top octomer layer have dynamic behavior while (√(2)×√(2)) and hexamer were static. • A model is presented to explain sulfur multilayer formation on Au(100). - Abstract: Piperazine-dithiocarbamate of potassium (K{sub 2}DTC{sub 2}pz) was used as a new precursor for the spontaneous deposition of sulfur on the Au(100) surface in alkaline solution. Two new sulfur phases were studied by scanning tunneling microscopy (STM). These phases were formed by six sulfur atoms (S{sub 6} phase, hexamer) and by four sulfur atoms (S{sub 4} phase, tetramer with (√(2)×√(2)) structure), and they were observed in coexistence with the well-known quasi-square patterns formed by eight sulfur atoms (S{sub 8} phase, octomer). A model was proposed where sulfur multilayers were formed by a (√(2)×√(2)) phase adsorbed directly on the gold surface while one of the other structures: hexamers or octomers were deposited on top. Sulfur layers were formed on gold terraces, vacancies and islands produced by lifting reconstructed surface. Sequential high-resolution STM images allowed the direct observation of the dynamic of the octomers, while the (√(2)×√(2)) structure remained static. Images also showed the reversible association/dissociation of the octomer.

  1. Effect of the salt-induced micellar microstructure on the nonlinear shear flow behavior of ionic cetylpyridinium chloride surfactant solutions

    Science.gov (United States)

    Gaudino, D.; Pasquino, R.; Kriegs, H.; Szekely, N.; Pyckhout-Hintzen, W.; Lettinga, M. P.; Grizzuti, N.

    2017-03-01

    The shear flow dynamics of linear and branched wormlike micellar systems based on cetylpyridinium chloride and sodium salicylate in brine solution is investigated through rheometric and scattering techniques. In particular, the flow and the structural flow response are explored via velocimetry measurements and rheological and rheometric small-angle neutron scattering (SANS) experiments, respectively. Although all micellar solutions display a similar shear thinning behavior in the nonlinear regime, the experimental results show that shear banding sets in only when the micelle contour length L ¯ is sufficiently long, independent of the nature of the micellar connections (either linear or branched micelles). Using rheometric SANS, we observe that the shear banding systems both show very similar orientational ordering as a function of Weissenberg number, while the short branched micelles manifest an unexpected increase of ordering at very low Weissenberg numbers. This suggests the presence of an additional flow-induced relaxation process that is peculiar for branched systems.

  2. Thermoelastic analysis of spent fuel and high level radioactive waste repositories in salt. A semi-analytical solution. [JUDITH

    Energy Technology Data Exchange (ETDEWEB)

    St. John, C.M.

    1977-04-01

    An underground repository containing heat generating, High Level Waste or Spent Unreprocessed Fuel may be approximated as a finite number of heat sources distributed across the plane of the repository. The resulting temperature, displacement and stress changes may be calculated using analytical solutions, providing linear thermoelasticity is assumed. This report documents a computer program based on this approach and gives results that form the basis for a comparison between the effects of disposing of High Level Waste and Spent Unreprocessed Fuel.

  3. Hydration and ion pair formation in common aqueous La(III) salt solutions--a Raman scattering and DFT study.

    Science.gov (United States)

    Rudolph, Wolfram W; Irmer, Gert

    2015-01-01

    Raman spectra of aqueous lanthanum perchlorate, triflate (trifluorosulfonate), chloride and nitrate solutions were measured over a broad concentration (0.121-3.050 mol L(-1)) range at room temperature (23 °C). A very weak mode at 343 cm(-1) with a full width at half height at 49 cm(-1) in the isotropic spectrum suggests that the nona-aqua La(III) ion is thermodynamically stable in dilute perchlorate solutions (∼0.2 mol L(-1)) while in concentrated perchlorate solutions outer-sphere ion pairs and contact ion pairs are formed. The La(3+) nona-hydrate was also detected in a 1.2 mol L(-1) La(CF3SO3)3(aq). In lanthanum chloride solutions chloro-complex formation was detected over the measured concentration range from 0.5-3.050 mol L(-1). The chloro-complexes in LaCl3(aq) are fairly weak and disappear with dilution. At a concentration complexes disappeared. In LaCl3 solutions, with additional HCl, a series of chloro-complexes of the type [La(OH2)(9-n)Cln](+3-n) (n = 1-3) were formed. The La(NO3)3(aq) spectra were compared with a spectrum of a 0.409 mol L(-1) NaNO3(aq) and it was concluded that in La(NO3)3(aq) over the concentration range from 0.121-1.844 mol L(-1), nitrato-complexes, [La(OH2)(9-n)(NO3)n](+3-n) (n = 1, 2) were formed. These nitrato-complexes are quite weak and disappear with dilution La(OH2)9](3+) with the polarizable dielectric continuum are in good agreement with data from recent structural experimental measurements and high quality simulations. The DFT frequency of the La-O stretching mode at 328.2 cm(-1), is only slightly smaller than the experimental one.

  4. Statistical mechanics of sum frequency generation spectroscopy for the liquid-vapor interface of dilute aqueous salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Noah-Vanhoucke, Joyce; Smith, Jared D.; Geissler, Phillip L.

    2009-01-02

    We demonstrate a theoretical description of vibrational sum frequency generation (SFG) at the boundary of aqueous electrolyte solutions. This approach identifies and exploits a simple relationship between SFG lineshapes and the statistics of molecular orientation and electric field. Our computer simulations indicate that orientational averages governing SFG susceptibility do not manifest ion-specific shifts in local electric field, but instead, ion-induced polarization of subsurface layers. Counterbalancing effects are obtained for monovalent anions and cations at the same depth. Ions held at different depths induce an imbalanced polarization, suggesting that ion-specific effects can arise from weak, long ranged influence on solvent organization.

  5. The effects of replacing the water model while decoupling water-water and water-solute interactions on computed properties of simple salts

    Science.gov (United States)

    Li, Jicun; Wang, Feng

    2016-07-01

    The effects of decoupling the water-water and water-solute interactions are studied with selected mono-valent ions as the solute. Using the ion-water cross terms developed for the BLYPSP-4F water model, we replaced the water potential with WAIL, TIP4P, and TIP3P without changing the ion-water parameters. When the adaptive force matching (AFM) derived BLYPSP-4F model is replaced by the other AFM derived WAIL model, the difference in ion properties, such as hydration free energies, radial distribution functions, relative diffusion constants, is negligible, demonstrating the feasibility for combining AFM parameters from different sources. Interestingly, when the AFM-derived ion-water cross-terms are used with a non-AFM based water model, only small changes in the ion properties are observed. The final combined models with TIP3P or TIP4P water reproduce the salt hydration free energies within 6% of experiments. The feasibility of combining AFM models with other non-AFM models is of significance since such combinations allow more complex systems to be studied without specific parameterization. In addition, the study suggests an interesting prospect of reusing the cross-terms when a part of a general force field is replaced with a different model. The prevailing practice, which is to re-derive all cross-terms with combining rules, may not have been optimal.

  6. Lightweight Heat Resistant Geopolymer-based Materials Synthesized from Red Mud and Rice Husk Ash Using Sodium Silicate Solution as Alkaline Activator

    Directory of Open Access Journals (Sweden)

    Hoc Thang Nguyen

    2017-01-01

    Full Text Available Geopolymer is an inorganic polymer composite with potentials to replace Ordinary Portland Cement (OPC-based materials in the future because of its lower energy consumption, minimal CO2 emissions and lower production cost as it utilizes industrial waste resources. Hence, geopolymerization and the process to produce geopolymers for various applications like building materials can be considered as green industry. Moreover, in our study, the raw materials we used are red mud and rice husk ash, which are are industrial and agricultural wastes that need to be managed to reduce their impact to the environment. The red mud and rice husk ash combined with sodium silicate (water glass solution were mixed to form geopolymer materials. Moreover, the geopolymer specimens were also tested for heat resistance at a temperature of 1000°C for 2 hours. Results suggest high heat resistance with an increase of compressive strength after exposed at high temperature.

  7. Initiation of nuclear reactions under laser irradiation of Au nanoparticles in the aqueous solution of Uranium salt

    CERN Document Server

    Simakin, A V

    2010-01-01

    Laser exposure of suspension of either gold or palladium nanoparticles in aqueous solutions of UO2Cl2 of natural isotope abundance was experimentally studied. Picosecond Nd:YAG lasers at peak power from 1011 to 1013 W/cm2 at the wavelength of 1064 and 355 nm were used as well as a visible-range Cu vapor laser at peak power of 1010 W/cm2. The composition of colloidal solutions before and after laser exposure was analyzed using atomic absorption and gamma spectroscopy between 0.06 and 1 MeV range of photon energy. A real-time gamma-spectroscopy was used to characterize the kinetics of nuclear reactions during laser exposure. It was found that laser exposure initiated nuclear reactions involving both 238U and 235U nuclei via different channels in H2O and D2O. The influence of saturation of both the liquid and nanoparticles by gaseous H2 and D2 on the kinetics of nuclear transformations was found. Possible mechanisms of observed processes are discussed.

  8. Structure and thermodynamics of nonideal solutions of colloidal particles. Investigation of salt-free solutions of human serum albumin by using small-angle neutron scattering and Monte Carlo simulation

    DEFF Research Database (Denmark)

    Sjøberg, B.; Mortensen, K.

    1997-01-01

    Carlo simulation, to study salt-free solutions of human serum albumin (HSA) in the concentration range up to 0.26 g ml(-1). The model calculations of the theoretical SANS intensities are quite general, thus avoiding the approximation that the relative positions and orientations of the particles...... are independent of each other. The computation of the theoretical intensities also includes the calculation of a 'thermodynamic' intensity scattered at zero angle, which is obtained via the nonideal part of the chemical potential. The latter quantity is obtained by applying the test particle method during...... the Monte Carlo simulations. It is found that the SANS data can be explained by a model where the HSA molecules behave as hard ellipsoids of revolution with semiaxes a = 6.8 nm, b = c = 1.9 nm. In addition to the hard core interaction, the particles are also surrounded by a soft, repulsive rectangular...

  9. Alkaline battery operational methodology

    Science.gov (United States)

    Sholklapper, Tal; Gallaway, Joshua; Steingart, Daniel; Ingale, Nilesh; Nyce, Michael

    2016-08-16

    Methods of using specific operational charge and discharge parameters to extend the life of alkaline batteries are disclosed. The methods can be used with any commercial primary or secondary alkaline battery, as well as with newer alkaline battery designs, including batteries with flowing electrolyte. The methods include cycling batteries within a narrow operating voltage window, with minimum and maximum cut-off voltages that are set based on battery characteristics and environmental conditions. The narrow voltage window decreases available capacity but allows the batteries to be cycled for hundreds or thousands of times.

  10. Synthesis, crystal structure and investigation of mononuclear copper(II) and zinc(II) complexes of a new carboxylate rich tripodal ligand and their interaction with carbohydrates in alkaline aqueous solution.

    Science.gov (United States)

    Stewart, Christopher D; Pedraza, Mayra; Arman, Hadi; Fan, Hua-Jun; Schilling, Eduardo Luiz; Szpoganicz, Bruno; Musie, Ghezai T

    2015-08-01

    A new carboxylate rich asymmetric tripodal ligand, N-[2-carboxybenzomethyl]-N-[carboxymethyl]-β-alanine (H3camb), and its di-copper(II), (NH4)2[1]2, and di-zinc(II), ((CH3)4N)2[2]2, complexes have been synthesized as carbohydrate binding models in aqueous solutions. The ligand and complexes have been fully characterized using several techniques, including single crystal X-ray diffraction. The interactions of (NH4)2[1]2 and ((CH3)4N)2[2]2 with D-glucose, D-mannose, D-xylose and xylitol in aqueous alkaline media were investigated using UV-Vis and (13)C-NMR spectroscopic techniques, respectively. The molar conductance, NMR and ESI-MS studies indicate that the complexes dissociate in solution to produce the respective complex anions, 1(-) and 2(-). Complexes 1(-) and 2(-) showed chelating ability towards the naturally abundant and biologically relevant sugars, D-glucose, D-mannose, D-xylose, and xylitol. The complex ions bind to one molar equivalent of the sugars, even in the presence of stoichiometric excess of the substrates, in solution. Experimentally obtained spectroscopic data and computational results suggest that the substrates bind to the metal center in a bidentate fashion. Apparent binding constant values, pK(app), between the complexes and the substrates were determined and a specific mode of substrate binding is proposed. The pK(app) and relativistic density functional theory (DFT) calculated Gibbs free energy values indicate that D-mannose displayed the strongest interaction with the complexes. Syntheses, characterizations, detailed substrate binding studies using spectroscopic techniques, single crystal X-ray diffraction and geometry optimizations of the complex-substrates with DFT calculations are also reported.

  11. A novel salt of antidiabetic drug metformin resulting from a proton transfer reaction: Synthesis, characterization, crystal structure and solution studies

    Science.gov (United States)

    Ghasemi, Fatemeh; Ghasemi, Khaled; Rezvani, Ali Reza; Shokrollahi, Ardeshir; Refahi, Masoud; García-Granda, Santiago; Mendoza-Meroño, Rafael

    2017-03-01

    Reaction between N,N-dimethylebiguanidine, Met = Metformin, and 4-hydroxy-2,6-pyridinedicarboxylic acid, HO-dipicH2, results in the formation of a novel proton transfer compound, [MetH2][HO-dipicH]2·H2O, 1. The characterization was performed using FTIR, UV-Vis, 1H and 13C NMR spectroscopy and X-ray crystallography. The crystal system is triclinic with space group P 1 bar and two molecules per unit cell. The protonation constants of O-dipic and Met, in all of probability protonated forms, and the equilibrium constants for the O-dipic-Met proton transfer system were investigated by the potentiometric pH titration method using the Hyperquad2008 program. The stoichiometry of the proton transfer species in solution were in agreement with the solid state result.

  12. Evaluation of some bean lines tolerance to alkaline soil

    Directory of Open Access Journals (Sweden)

    Abeer A. Radi

    2012-01-01

    Full Text Available Introduction: In less arid climates, salts are less concentrated and sodium dominates in carbonate and bicarbonate forms, which enhance the formation of alkaline soils. The development and identification of salt-tolerant crop cultivars or lines would complement salt management programs to improve the productivity and yields of salt stressed plants.Materials and methods: This work was to study the evaluation of alkalinity tolerance of some bean lines grown under different levels of sodium carbonate (Na2CO3 to select the most alkalinity tolerant lines versus the most-sensitive ones out of 6 lines of the test plants.Results: The symptoms induced by alkalinity included reduction in root, shoot growth, and leaf area which were more severe in some bean lines. Potassium leakage was severely affected by alkalinity in some lines at all tested levels, while in some others a moderate damage was manifested only at the higher levels. The increase in Na2CO3 level was associated with a gradual fall in chlorophyll a and b biosynthesis of all the test bean lines. However, alkalinity at low and moderate levels had a favorable effect on the biosynthesis of carotenoids in all the test bean lines. The increase in Na2CO3 supply had a considerable stimulatory effect on sodium accumulation, while potassium accumulation fluctuated in organs of bean lines.Conclusion: Assiut 1104 out of all the different lines investigated was found to display the lowest sensitivity to alkalinity stress, while Assiut 12/104 was the most sensitive one.

  13. The stability of hydrogen evolution activity and corrosion behavior of NiCu coatings with long-term electrolysis in alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Solmaz, Ramazan; Doener, Ali; Kardas, Guelfeza [Cukurova University, Science and Letters Faculty, Chemistry Department, 01330, Balcali, Adana (Turkey)

    2009-03-15

    In this study, NiCu composite coating was electrochemically deposited on a copper electrode (Cu/NiCu) and tested for hydrogen evolution reaction (HER) in 1 M KOH solution for long-term electrolysis with the help of cathodic current-potential curves and electrochemical impedance spectroscopy (EIS) techniques. The bulk and surface composition of the coating was determined using atomic absorption spectroscopy (AAS) and energy dispersive X-ray (EDX) analysis. The surface morphology was investigated by scanning electron microscopy (SEM). The effect of electrolysis on the corrosion behavior of the Cu/NiCu electrode was also reported. It was found that the NiCu coating had a compact and porous structure with good time stability. The HER activity of the coating was stable over 120 h electrolysis and the HER mechanism was not modified during the operation. The corrosion tests showed that the corrosion resistance of the Cu/NiCu electrode changed when a cathodic current was applied to the electrolysis system. (author)

  14. SrCo1‑xTixO3‑δ perovskites as excellent catalysts for fast degradation of water contaminants in neutral and alkaline solutions

    Science.gov (United States)

    Miao, Jie; Sunarso, Jaka; Su, Chao; Zhou, Wei; Wang, Shaobin; Shao, Zongping

    2017-03-01

    Perovskite-like oxides SrCo1‑xTixO3‑δ (SCTx, x = 0.1, 0.2, 0.4, 0.6) were used as heterogeneous catalysts to activate peroxymonosulfate (PMS) for phenol degradation under a wide pH range, exhibiting more rapid phenol oxidation than Co3O4 and TiO2. The SCT0.4/PMS system produced a high activity at increased initial pH, achieving optimized performance at pH ≥ 7 in terms of total organic carbon removal, the minimum Co leaching and good catalytic stability. Kinetic studies showed that the phenol oxidation kinetics on SCT0.4/PMS system followed the pseudo-zero order kinetics and the rate on SCT0.4/PMS system decreased with increasing initial phenol concentration, decreased PMS amount, catalyst loading and solution temperature. Quenching tests using ethanol and tert-butyl alcohol demonstrated sulfate and hydroxyl radicals for phenol oxidation. This investigation suggested promising heterogeneous catalysts for organic oxidation with PMS, showing a breakthrough in the barriers of metal leaching, acidic pH, and low efficiency of heterogeneous catalysis.

  15. SrCo1−xTixO3−δ perovskites as excellent catalysts for fast degradation of water contaminants in neutral and alkaline solutions

    Science.gov (United States)

    Miao, Jie; Sunarso, Jaka; Su, Chao; Zhou, Wei; Wang, Shaobin; Shao, Zongping

    2017-01-01

    Perovskite-like oxides SrCo1−xTixO3−δ (SCTx, x = 0.1, 0.2, 0.4, 0.6) were used as heterogeneous catalysts to activate peroxymonosulfate (PMS) for phenol degradation under a wide pH range, exhibiting more rapid phenol oxidation than Co3O4 and TiO2. The SCT0.4/PMS system produced a high activity at increased initial pH, achieving optimized performance at pH ≥ 7 in terms of total organic carbon removal, the minimum Co leaching and good catalytic stability. Kinetic studies showed that the phenol oxidation kinetics on SCT0.4/PMS system followed the pseudo-zero order kinetics and the rate on SCT0.4/PMS system decreased with increasing initial phenol concentration, decreased PMS amount, catalyst loading and solution temperature. Quenching tests using ethanol and tert-butyl alcohol demonstrated sulfate and hydroxyl radicals for phenol oxidation. This investigation suggested promising heterogeneous catalysts for organic oxidation with PMS, showing a breakthrough in the barriers of metal leaching, acidic pH, and low efficiency of heterogeneous catalysis. PMID:28281656

  16. Determination of bisphenol A in thermal printing papers treated by alkaline aqueous solution using the combination of single-drop microextraction and HPLC.

    Science.gov (United States)

    Gao, Leihong; Zou, Jing; Liu, Haihong; Zeng, Jingbin; Wang, Yiru; Chen, Xi

    2013-04-01

    A method for the quantitative determination of bisphenol A in thermal printing paper was developed and validated. Bisphenol A was extracted from the paper samples using 2% NaOH solution, then the extracted analyte was enriched using single-drop microextraction followed by HPLC analysis. Several parameters relating to the single-drop microextraction efficiency including extraction solvent, extraction temperature and time, stirring rate, and pH of donor phase were studied and optimized. Spiked recovery of bisphenol A at 20 and 5 mg/g was found to be 95.8 and 108%, and the method detection limit and method quantification limit was 0.03 and 0.01 mg/g, respectively. Under the optimized conditions, the proposed method was applied to the determination of bisphenol A in seven types of thermal printing paper samples, and the concentration of bisphenol A was found in the range of 0.53-20.9 mg/g. The considerably minimum usage of organic solvents (5 μL 1-octanol) and high enrichment factor (189-197) in the sample preparation are the two highlighted advantages in comparison with previously published works.

  17. A study of X100 pipeline steel passivation in mildly alkaline bicarbonate solutions using electrochemical impedance spectroscopy under potentiodynamic conditions and Mott-Schottky

    Science.gov (United States)

    Gadala, Ibrahim M.; Alfantazi, Akram

    2015-12-01

    The key steps involved in X100 pipeline steel passivation in bicarbonate-based simulated soil solutions from the pre-passive to transpassive potential regions have been analyzed here using a step-wise anodizing-electrochemical impedance spectroscopy (EIS) routine. Pre-passive steps involve parallel dissolution-adsorption in early stages followed by clear diffusion-adsorption control shortly before iron hydroxide formation. Aggressive NS4 chlorides/sulfate promote steel dissolution whilst inhibiting diffusion in pre-passive steps. Diffusive and adsorptive effects remain during iron hydroxide formation, but withdraw shortly thereafter during its removal and the development of the stable iron carbonate passive layer. Passive layer protectiveness is evaluated using EIS fitting, current density analysis, and correlations with semiconductive parameters, consistently revealing improved robustness in colder, bicarbonate-rich, chloride/sulfate-free conditions. Ferrous oxide formation at higher potentials results in markedly lower impedances with disordered behavior, and the involvement of the iron(III) valence state is observed in Mott-Schottky tests exclusively for 75 °C conditions.

  18. Uranium in alkaline rocks

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, M.; Wollenberg, H.; Strisower, B.; Bowman, H.; Flexser, S.; Carmichael, I.

    1978-04-01

    Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential.

  19. Electrokinetic removal of Ca(NO3)2 from bricks to avoid salt induced decay

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Rörig-Dalgaard, Inge

    2007-01-01

    Salt-induced decay of masonry is a serious threat to our cultural heritage. In buildings near agricultural land or stables the masonry may suffer seriously from salt-induced decay from nitrates. It was investigated in laboratory scale with a single brick if Ca(NO$-3$/) $-2$/ could be removed...... by electromigration in an applied electric field. To relate the obtained nitrate concentrations to the danger for salt-induced decay the concentrations were compared with values from the Austrian ONORM B 3355-1. It was shown possible to even remove nitrate from bricks with initial concentrations in the range...... to obtain this low concentration all through the brick. Calcium removal was followed as well. On the contrary to nitrate, calcium was seen adsorbed in exchangeable sites to the internal brick surfaces and precipitation may also occur due to slight alkaline pore solution. Calcium was also removed during...

  20. Adapting protein solubility by glycosylation. N-glycosylation mutants of Coprinus cinereus peroxidase in salt and organic solutions.

    Science.gov (United States)

    Tams, J W; Vind, J; Welinder, K G

    1999-07-13

    Protein solubility is a fundamental parameter in biology and biotechnology. In the present study we have constructed and analyzed five mutants of Coprinus cinereus peroxidase (CIP) with 0, 1, 2, 4 and 6 N-glycosylation sites. All mutants contain Man(x)(GlcNAc)(2) glycans. The peroxidase activity was the same for wild-type CIP and all the glycosylation mutants when measured with the large substrate 2,2'-azino-bis(-3-ethylbenzthiazoline-6-sulfonic acid). The solubility of the five CIP mutants showed a linear dependence on the number of carbohydrate residues attached to the protein in buffered solution of both ammonium sulfate (AMS) and acetone, increasing in AMS and decreasing in acetone. Moreover, the change in free energy of solvation appears to be a constant, though with opposite signs in these solvents, giving DeltaDeltaG degrees (sol)=-0.32+/-0.05 kJ/mol per carbohydrate residue in 2.0 M AMS, a value previously obtained comparing ordinary and deglycosylated horseradish peroxidase, and 0. 37+/-0.10 kJ/mol in 60 v/v% acetone.

  1. Study of sulfur adlayers on Au(1 1 1) from basic hydrolysis of piperazine bis(dithiocarbamate) sodium salt

    Energy Technology Data Exchange (ETDEWEB)

    Martínez, Javier A. [Instituto de Ciencia y Tecnología de Materiales (IMRE), Universidad de La Habana, Zapata y G, El Vedado, Plaza de la Revolución, La Habana 10400 (Cuba); Valenzuela, José [Centro de Nanociencias y Nanotecnología (CNyN), Universidad Nacional Autónoma de México (UNAM), km 107 Carretera Tijuana-Ensenada, Ensenada, BC 22860 (Mexico); Hernandez-Tamargo, Carlos E. [Laboratorio de Química Computacional y Teórica (LQCT), Facultad de Química, Universidad de La Habana, Zapata y G, El Vedado, Plaza de la Revolución, La Habana 10400 (Cuba); Cao-Milán, Roberto [Laboratorio de Bioinorgánica (LBI), Facultad de Química, Universidad de La Habana, Zapata y G, El Vedado, Plaza de la Revolución, La Habana 10400 (Cuba); Herrera, José A. [Instituto de Ciencia y Tecnología de Materiales (IMRE), Universidad de La Habana, Zapata y G, El Vedado, Plaza de la Revolución, La Habana 10400 (Cuba); Díaz, Jesús A.; Farías, Mario H. [Centro de Nanociencias y Nanotecnología (CNyN), Universidad Nacional Autónoma de México (UNAM), km 107 Carretera Tijuana-Ensenada, Ensenada, BC 22860 (Mexico); Mikosch, Hans [Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/E164-EC, 1060 Vienna (Austria); and others

    2015-08-01

    Highlights: • S adlayer formation from descomposition of piperazine bis(dithiocarbamate) sodium salt under alkaline conditions. • Quasi-rectangular octomers (eight sulfur atoms) coexist with another phase. • A DFT surface model of four S-dimers arranged as octomers reproduced real STM images. - Abstract: Sulfur adlayers on Au(1 1 1) were obtained after the interaction of a gold substrate with an alkaline solution of piperazine bis(dithiocarbamate) sodium salt. Characterization of the sulfur modified gold surface was performed by means of X-Ray Photoelectron Spectroscopy (XPS), Scanning Tunneling Microscopy (STM) and Density Functional Theory (DFT) calculations. XPS signals indicated the presence of S–Au bonds, monomeric and polymeric sulfur, and absence of nitrogen and sodium. Images from STM showed the formation of quasi-rectangular octomers in coexistence with another phase. A DFT model using the arrangement of sulfur dimers on the Au(1 1 1) surface effectively reproduced the experimental STM images.

  2. A scanning tunneling microscopy investigation of the phases formed by the sulfur adsorption on Au(100) from an alkaline solution of 1,4-piperazine(bis)-dithiocarbamate of potassium

    Science.gov (United States)

    Martínez, Javier A.; Valenzuela B., José; Cao Milán, R.; Herrera, José; Farías, Mario H.; Hernández, Mayra P.

    2014-11-01

    Piperazine-dithiocarbamate of potassium (K2DTC2pz) was used as a new precursor for the spontaneous deposition of sulfur on the Au(100) surface in alkaline solution. Two new sulfur phases were studied by scanning tunneling microscopy (STM). These phases were formed by six sulfur atoms (S6 phase, hexamer) and by four sulfur atoms (S4 phase, tetramer with (√{ 2} ×√{ 2}) structure), and they were observed in coexistence with the well-known quasi-square patterns formed by eight sulfur atoms (S8 phase, octomer). A model was proposed where sulfur multilayers were formed by a (√{ 2} ×√{ 2}) phase adsorbed directly on the gold surface while one of the other structures: hexamers or octomers were deposited on top. Sulfur layers were formed on gold terraces, vacancies and islands produced by lifting reconstructed surface. Sequential high-resolution STM images allowed the direct observation of the dynamic of the octomers, while the (√{ 2} ×√{ 2}) structure remained static. Images also showed the reversible association/dissociation of the octomer.

  3. Exchange reactions between a molten salt and a solution of tri-butyl phosphate in a liquid silicone; Reactions d'echange entre un sel fondu et une solution de phosphate de tributyle dans un silicone liquide

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-07-01

    Present interest centred around molten salts can be explained by their possible use in the field of nuclear energy, in particular as a support for fuels and also as reprocessing agents. It seemed of interest to consider the molten salt as a solvent and to study partition phenomena with a second phase stable at high temperatures. The salt chosen is a ternary eutectic of alkali nitrates and the second phase is a solution of tri-butyl phosphate in a liquid silicone. The working temperature is fixed at 150 deg. C. We have studied first of all the stability of the two phases and their mutual solubilities at this temperature. It has been shown that the two solvents are immiscible and stable. We have also described the extraction by the silicone solution of various products in solution in the salt phase, and have determined the partition coefficients and the formulae of the extracted molecules. It has been possible to calculate the partition coefficients of the following ions extracted as nitrates: Li{sup +}, Na{sup +}, K{sup +}, Sr{sup 2+}, Ca{sup 2+}, Ba{sup 2+}, Hg{sup 2+} whose partition coefficients are very low: Mg{sup 2+}, Ni{sup 2+}, Co{sup 2+}, Zn{sup 2+} whose extraction yields are greater than 50 per cent; finally Ce{sup 3+}, La{sup 3+}, UO{sub 2}{sup 2+}, highly extracted. Also the following anions have been extracted in the form of alkali salts: F{sup -}, Cl{sup -}, Br{sup -}, I{sup -}, IO{sub 3}{sup -}, CN{sup -}, SO{sub 4}{sup -}, C{sub 2}O{sub 4}{sup -}, NO{sub 2}{sup -}. Amongst these, only the halogens have non-negligible partition coefficients. In certain particular cases we have been able to study the influence of complex formation on the extraction phenomena. Two applications are described: - The separation of two products by complex formation and extraction (separation of magnesium from cobalt, nickel and zinc); - The calculation of the equilibrium constant of a complex by measurement of the variation in the partition coefficient of the ion complexed

  4. Alkaline electrochemical cells and method of making

    Science.gov (United States)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1970-01-01

    Equilibrated cellulose ether membranes of increased electrolytic conductivity for use as separators in concentrated alkaline electrochemical cells are investigated. The method of making such membranes by equilibration to the degree desired in an aqueous alkali solution mantained at a temperature below about 10 C is described.

  5. Investigation of the effect of additives on the basis of pickling solutions containing iron salts on the structure and strength of fine concrete

    Directory of Open Access Journals (Sweden)

    Lukuttsova Natal’ya Petrovna

    2016-01-01

    Full Text Available The modern tendencies of construction industry development are connected with the use of new high-efficient materials with the application of resource- and energy-saving technologies of their generation. The use of industrial man-made products as the components improving the characteristics of construction products is now a promising field of research. The article presents the results of the use of waste pickling solutions of steel rolling factories, containing salts of iron as nanomodified additives for the products based on cement binder. The effectiveness of the influence of the considered additives on the structure and strength of fine-grained concrete is shown. If using this additive in the amount of 0.32 % from the mass of cement for 28 days of natural hardening, the fine concrete strength is growing by 1.8 times due to additional formation of hydrosilicates, densification of structure and reduction of the total porosity of the cement system by 2 times.

  6. THE ADDITION OF CAFFEINE IN EARLE’S BALANCED SALT SOLUTION MEDIA WITH WASHING UP METHOD INCREASE MEMBRANE INTEGRITY AND ACROSOMAL SPERM

    Directory of Open Access Journals (Sweden)

    B. K. Satriyasa

    2014-12-01

    Full Text Available Background: caffeine, a methylxanthine derivate, appears to inhibit phosphodiesterase, thereby inhibiting the break down of cAMP and increasing its concentration inside cell. This study aims to assess the effect of caffeine addition in Earles’s Balanced Salt Solution (EBSS on the increase in membrane integrity and acrosome reaction of spermatozoa using swim up method. Methods: This study was carried out at the Clinic of Sexology and Andrology, Sanglah Public Hospital at Denpasar Bali-Indonesia. This study was an experimental study using the design of pre and post test paired control group design. The samples were sperm specimens of eighteen infertile couple male or volunteers who were infertile with age ranged between 20-40 years old. The samples   were divided into two groups: treatment group (caffeine + EBSS and control group (EBSS. The data were analysed statistically by normality test (Kolmogorov - Smirnov Goodness of Fit Test, Homogeneity test, and Paired Student’s t test.  Results: The results showed that the caffeine addition in EBSS medium could increase significantly (p<0.05.  The integrity of the sperm membrane obtained were from 81.30 % to 86.60 % and acrosomal reaction from 82.60% to 89.60% evaluated by hypo-osmotic swelling test (HOS. The conclusion of this study is that addition of caffeine in EBSS medium increases significantly membrane integrity and acrosomal reaction of the human sperm.

  7. Cr(VI) sorption behavior from aqueous solutions onto polymeric microcapsules containing a long-chain quaternary ammonium salt: Kinetics and thermodynamics analysis

    Energy Technology Data Exchange (ETDEWEB)

    Barassi, Giancarlo; Valdes, Andrea; Araneda, Claudio; Basualto, Carlos; Sapag, Jaime; Tapia, Cristian [Laboratorio de Operaciones Unitarias, Facultad de Ciencias Quimicas y Farmaceuticas, Universidad de Chile, Av. Vicuna Mackenna 20, Santiago (Chile); Valenzuela, Fernando, E-mail: fvalenzu@uchile.cl [Laboratorio de Operaciones Unitarias, Facultad de Ciencias Quimicas y Farmaceuticas, Universidad de Chile, Av. Vicuna Mackenna 20, Santiago (Chile)

    2009-12-15

    This work studies the adsorption of Cr(VI) ions from an aqueous acid solution on hydrophobic polymeric microcapsules containing a long-chain quaternary ammonium salt-type extractant immobilized in their pore structure. The microcapsules were synthesized by adding the extractant Aliquat 336 during the in situ radical copolymerization of the monomers styrene (ST) and ethylene glycol dimethacrylate (EGDMA). The microcapsules, which had a spherical shape with a rough surface, behaved as efficient adsorbents for Cr(VI) at the tested temperatures. The results of kinetics experiments carried out at different temperatures showed that the adsorption process fits well to a pseudo-second-order with an activation energy of 82.7 kJ mol{sup -1}, confirming that the sorption process is controlled by a chemisorption mechanism. Langmuir's isotherms were found to represent well the experimentally observed sorption data. Thermodynamics parameters, namely, changes in standard free energy ({Delta}G{sup 0}), enthalpy ({Delta}H{sup 0}), and entropy ({Delta}S{sup 0}), are also calculated. The results indicate that the chemisorption process is spontaneous and exothermic. The entropy change value measured in this study shows that metal adsorbed on microcapsules leads to a less chaotic system than a liquid-liquid extraction system.

  8. The waste isolation pilot plant. Permanent isolation of defense transuranic waste in deep geologic salt. A national solution and international model

    Energy Technology Data Exchange (ETDEWEB)

    Franco, Jose; Van Luik, Abraham [US Department of Energy, Carlsbad, NM (United States). Carlsbad Field Office

    2015-07-01

    management solution. The operational lessons learned from these two incidents will be available to be shared with other geologic repository programs. Neither of these two operational incidents call into question the suitability of rock salt as a repository host rock. Both incidents point to a need to take care to evaluate all potential consequences in making decisions about underground equipment maintenance and housekeeping, and to make a greater effort to assure that measures are taken to mitigate lower likelihood events and to practice emergency egress procedures until they are second nature to the workforce.

  9. Strength properties of separators in alkaline solutions

    Energy Technology Data Exchange (ETDEWEB)

    Danko, T. [Viskase Corp., Chicago, IL (United States)

    1996-11-01

    Battery separator non-wovens that were coated with regenerated cellulose via the viscose process were subjected to storage in 40% potassium hydroxide (KOH) over a two month period. Samples were periodically checked for wet MD tensile strength. The test showed that among the non-wovens, the polyamide retained about 93% of its initial tensile strength whereas polyvinyl alcohol and cellulosic non-wovens retained only 55% and 35%, respectively. Adding a viscose coating to the non-wovens improved tensile strength retention by 20--25% for the polyvinyl alcohol and cellulosic materials. The viscose-coated polyamide retained more than 98% of its initial tensile strength.

  10. Alkaline earth metal thioindates

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov-Ehmin, B.N.; Ivlieva, V.I.; Filatenko, L.A.; Zajtsev, B.E.; Kaziev, G.Z.; Sarabiya, M.G.

    1984-08-01

    Alkaline earth metal thioindates of MIn/sub 2/S/sub 4/ composition were synthesized by interaction of alkaline earth metal oxoindates with hydrogen sulfide during heating. Investigation into the compounds by X-ray analysis showed that calcium compound crystallizes in cubic crystal system and strontium and barium compounds in rhombic crystal system. Lattice parameters and the number of formula units were determined. Thioindates of M/sub 3/In/sub 2/S/sub 6/ composition were synthesized, their individuality was shown.

  11. Crushed Salt Constitutive Model

    Energy Technology Data Exchange (ETDEWEB)

    Callahan, G.D.

    1999-02-01

    The constitutive model used to describe the deformation of crushed salt is presented in this report. Two mechanisms -- dislocation creep and grain boundary diffusional pressure solution -- are combined to form the basis for the constitutive model governing the deformation of crushed salt. The constitutive model is generalized to represent three-dimensional states of stress. Upon complete consolidation, the crushed-salt model reproduces the Multimechanism Deformation (M-D) model typically used for the Waste Isolation Pilot Plant (WIPP) host geological formation salt. New shear consolidation tests are combined with an existing database that includes hydrostatic consolidation and shear consolidation tests conducted on WIPP and southeastern New Mexico salt. Nonlinear least-squares model fitting to the database produced two sets of material parameter values for the model -- one for the shear consolidation tests and one for a combination of the shear and hydrostatic consolidation tests. Using the parameter values determined from the fitted database, the constitutive model is validated against constant strain-rate tests. Shaft seal problems are analyzed to demonstrate model-predicted consolidation of the shaft seal crushed-salt component. Based on the fitting statistics, the ability of the model to predict the test data, and the ability of the model to predict load paths and test data outside of the fitted database, the model appears to capture the creep consolidation behavior of crushed salt reasonably well.

  12. Salt treatment Fukushima

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Stefan [NUKEM Technologies GmbH, Alzenau (Germany)

    2013-07-01

    The Task of NUKEM Technologies GmbH is to develop a technical solution for the treatment of salt containing effluents at Fukushima Daiichi. The target of the treatment is a solidified product suitable for the safe storage on site. Therefore, NUKEM investigated several technologies (direct cementation, drying and storage, drying and subsequent cementation) in order to find a fit for purpose solution. The following tasks have been considered: (a) Mechanical strength and homogeneity of the product; (b) Cost efficient solution (cost for the drying system vs. reduced amount of storage containers); (c) Proven technology; (d) On site storage. NUKEM made some practical test in parallel with different recipes. The aim was to embed as much as possible salt quantity into the cement matrix, but still meet the requested mechanical strength and required homogeneity. As a result NUKEM recommended to apply the following technologies (a) a drying system, to produce a dry salt product (b) a cementation facility, to generate a homogeneous salt/cement matrix (c) a filling station with attached CMS (Container measuring station) to fill the resulting cement/salt matrix into containers suitable for the storage at Fukushima Daiichi. (orig.)

  13. Inhibition Behaviour of 2-butine1, 4diol and Tartrate Salt, and Their Synergistic Effects on Corrosion of AA3003 Aluminium Alloy in 0.5% NaCl Solution

    Institute of Scientific and Technical Information of China (English)

    Taghi Shahrabi; Alireza Yazdzad; Mirghasem Hosseini

    2008-01-01

    This work intends to investigate the inhibition behaviour of 2-butine 1, 4diol and potassium sodium tartrate and their synergistic effects on 3003 aluminium alloy corrosion in 0.5% NaCl solution. Experiments were carried out by electrochemical impedance spectroscopy (EIS) and Tafel polarization method in a three-electrode cell. It was concluded that the inhibition efficiencies increased with an increase in the concentrations of inhibitors. For 2-butinel, 4diol and tartrate salt, the optimum in the inhibition efficiency, at room temperature and neutral pH, was observed for concentrations close to 10-3 mol/L and 1.5×10-3mol/L, respectively. The electrochemical results illustrated that 2-butine1, 4diol and tartrate salt, have significant synergistic inhibition effects on corrosion of 3003 aluminium alloy in 0.5% NaCl solution. The optimum ratio of concentrations for tartrate to alcohol was 2:1.

  14. Free energetics of carbon nanotube association in aqueous inorganic NaI salt solutions: Temperature effects using all-atom molecular dynamics simulations.

    Science.gov (United States)

    Ou, Shu-Ching; Cui, Di; Wezowicz, Matthew; Taufer, Michela; Patel, Sandeep

    2015-06-15

    In this study, we examine the temperature dependence of free energetics of nanotube association using graphical processing unit-enabled all-atom molecular dynamics simulations (FEN ZI) with two (10,10) single-walled carbon nanotubes in 3 m NaI aqueous salt solution. Results suggest that the free energy, enthalpy and entropy changes for the association process are all reduced at the high temperature, in agreement with previous investigations using other hydrophobes. Via the decomposition of free energy into individual components, we found that solvent contribution (including water, anion, and cation contributions) is correlated with the spatial distribution of the corresponding species and is influenced distinctly by the temperature. We studied the spatial distribution and the structure of the solvent in different regions: intertube, intratube and the bulk solvent. By calculating the fluctuation of coarse-grained tube-solvent surfaces, we found that tube-water interfacial fluctuation exhibits the strongest temperature dependence. By taking ions to be a solvent-like medium in the absence of water, tube-anion interfacial fluctuation shows similar but weaker dependence on temperature, while tube-cation interfacial fluctuation shows no dependence in general. These characteristics are discussed via the malleability of their corresponding solvation shells relative to the nanotube surface. Hydrogen bonding profiles and tetrahedrality of water arrangement are also computed to compare the structure of solvent in the solvent bulk and intertube region. The hydrophobic confinement induces a relatively lower concentration environment in the intertube region, therefore causing different intertube solvent structures which depend on the tube separation. This study is relevant in the continuing discourse on hydrophobic interactions (as they impact generally a broad class of phenomena in biology, biochemistry, and materials science and soft condensed matter research), and

  15. Síntese de "whiskers" de CaSiO3 em fluxo salino para elaboração de biomateriais Synthesis of CaSiO3 "whiskers" in alkaline salt flux for biomaterials reinforcement

    Directory of Open Access Journals (Sweden)

    M. Motisuke

    2012-12-01

    Full Text Available Há tempos empregam-se "whiskers" cerâmicos como reforço de materiais nas mais diversas aplicações, porém os materiais com os quais estes são comumente fabricados (carbeto e nitreto de silício não permitem a sua utilização no campo dos biomateriais devido sua elevada toxicidade. Assim, torna-se interessante sintetizar "whiskers" biocompatíveis capazes de reforçar biomateriais cerâmicos e poliméricos sem prejudicar a saúde dos pacientes. Dessa forma, este trabalho tem como objetivo desenvolver e determinar os parâmetros limitantes de uma nova rota de síntese por fusão de sais de "whiskers" de CaSiO3, uma biocerâmica biocompatível, bioativa e reabsorvível. Este método é simples, barato e permite a produção em larga escala. Utilizou-se um fluxo de NaCl/KCl a 900 ºC para sintetizar "whiskers" de wollastonita, que foram caracterizados por difração de raios X e microscopia eletrônica de varredura. O método proposto mostrou-se eficiente, entretanto os tempos de patamar empregados não foram suficientes para garantir 100% de rendimento da reação de formação de CaSiO3, ocorrendo a formação de cristobalita.Materials reinforcement by ceramic whiskers has been employed for a long time in a variety of industrial applications. Nevertheless, the materials by which these whiskers are commonly made of (carbide and silicon nitride do not allow their use in biomaterials field due to their high toxicity. Then, it is of interest to synthesize ceramic whiskers which could reinforce biocompatible ceramic and polymeric biomaterials without harming the patients' health. In this manner, the aim of this work is to propose and analyze the limiting process variables of a new synthetic route to produce whiskers of CaSiO3 (wollastonite: a biocompatible, bioactive and readsorbable biomaterial. It was employed the molten salt synthesis at 900 ºC to grow wollastonite crystals which were characterized by X-ray diffraction and scanning electron

  16. Imidazolium-Based Polymeric Materials as Alkaline Anion-Exchange Fuel Cell Membranes

    Science.gov (United States)

    Narayan, Sri R.; Yen, Shiao-Ping S.; Reddy, Prakash V.; Nair, Nanditha

    2012-01-01

    Polymer electrolyte membranes that conduct hydroxide ions have potential use in fuel cells. A variety of polystyrene-based quaternary ammonium hydroxides have been reported as anion exchange fuel cell membranes. However, the hydrolytic stability and conductivity of the commercially available membranes are not adequate to meet the requirements of fuel cell applications. When compared with commercially available membranes, polystyrene-imidazolium alkaline membrane electrolytes are more stable and more highly conducting. At the time of this reporting, this has been the first such usage for imidazolium-based polymeric materials for fuel cells. Imidazolium salts are known to be electrochemically stable over wide potential ranges. By controlling the relative ratio of imidazolium groups in polystyrene-imidazolium salts, their physiochemical properties could be modulated. Alkaline anion exchange membranes based on polystyrene-imidazolium hydroxide materials have been developed. The first step was to synthesize the poly(styrene-co-(1-((4-vinyl)methyl)-3- methylimidazolium) chloride through a free-radical polymerization. Casting of this material followed by in situ treatment of the membranes with sodium hydroxide solutions provided the corresponding hydroxide salts. Various ratios of the monomers 4-chloromoethylvinylbenzine (CMVB) and vinylbenzine (VB) provided various compositions of the polymer. The preferred material, due to the relative ease of casting the film, and its relatively low hygroscopic nature, was a 2:1 ratio of CMVB to VB. Testing confirmed that at room temperature, the new membranes outperformed commercially available membranes by a large margin. With fuel cells now in use at NASA and in transportation, and with defense potential, any improvement to fuel cell efficiency is a significant development.

  17. t-BAMBP-煤油溶液萃取盐湖卤水中铷和铯离子%Solvent extraction of rubidium and cesium from salt lake brine with t-BAMBP-kerosene solution

    Institute of Scientific and Technical Information of China (English)

    刘世明; 刘和辉; 黄云敬; 阳卫军

    2015-01-01

    The residues of salt lake brine from which potassium had been removed were used to extract Rb+and Cs+together with a sulphonated kerosene (SK) solution of 1.0 mol/L 4-tert-butyl-2-(α-methylbenzyl) phenol (t-BAMBP). Rb+and Cs+were enriched and separated effectively by precipitating Mg2+ before extraction and by scrubbing out K+ and Na+ repeatedly before stripping. The effects of the volume ratio of organic phase to aqueous extraction phase (O/A), alkalinity of aqueous phase (c(OH)−), interference from K+and Mg2+, and ratio the volume of organic phase to aqueous scrubbing phase (O/A′) were investigated. The experimental brine was extracted optimally by 5-stage extraction with 1.0 mol/L t-BAMBP in SK, c(OH−)=1 mol/L, and O/A=1:1. The scrubbing yield of rubidium was only about 10.5%when the extraction solvent was washed 3 times with 1×10−4 mol/L NaOH at O/A′=1:0.5. After 5-stage countercurrent extraction, the final extraction yields of Rb+and Cs+reached 95.04%and 99.80%, respectively.%将工厂提钾后的盐湖卤水作为提取Rb+和Cs+的实验用卤水,将萃取剂t-BAMBP的磺化煤油溶液作为有机相进行萃取。在萃取之前预先沉淀出镁并作为一种产品,在反萃前再多次洗涤分离出大部分的 K+和 Na+,最终使Rb+和Cs+得到有效富集和分离。研究油水相比(O/A)、水相的碱性(c(OH−)、K+和Mg2+的含量及洗涤油水相比(O/A′)对萃取过程的影响。最佳工艺条件为:1.0 mol/L的 t-BAMBP磺化煤油溶液,水相碱性c(OH−)=1 mol/L,油水相比O/A=1:1。当用1×10−4 mol/L NaOH溶液洗涤萃取油相3次,洗涤油水相比O/A′=1:0.5时,铷和铯的洗脱率仅为10.5%。经过5级逆流萃取,最终铷和铯的萃取率分别达到了95.04%与99.80%。

  18. Alkaline broadening in Stars

    CERN Document Server

    De Kertanguy, A

    2015-01-01

    Giving new insight for line broadening theory for atoms with more structure than hydrogen in most stars. Using symbolic software to build precise wave functions corrected for ds;dp quantum defects. The profiles obtained with that approach, have peculiar trends, narrower than hydrogen, all quantum defects used are taken from atomic database topbase. Illustration of stronger effects of ions and electrons on the alkaline profiles, than neutral-neutral collision mechanism. Keywords : Stars: fundamental parameters - Atomic processes - Line: profiles.

  19. The world of DNA in glycol solution.

    Science.gov (United States)

    Lindahl, Tomas

    2016-05-23

    The properties of high-molecular-weight DNA are usually investigated in neutral aqueous solutions. Strong acids and strong alkaline solutions are obviously unsuitable, as are corrosive solvents, and DNA is insoluble in most organic solvents; precipitation of DNA from aqueous solution with ethanol or isopropanol is therefore frequently used as a purification step. An exception is the organic solvent glycol (ethylene glycol, 1,2-ethanediol, dihydroxyethane, HOCH2CH2OH) and the similar solvent glycerol. Double-stranded DNA remains soluble in salt-containing glycol, although it precipitates in polyethylene glycol. (DNA also remains soluble in formamide, but the double-helical structure of DNA is much less stable in this solvent than in glycol.) However, DNA in glycol has been little investigated during the last half-century.

  20. Some durability aspects of hybrid alkaline cements

    Directory of Open Access Journals (Sweden)

    Donatello S.

    2014-04-01

    Full Text Available Blended cements that contain a high content of fly ash and a low content of Portland cement typically suffer from low early strength development and long setting times. Recently, one method of overcoming these problems has been to use an alkali activator to enhance the reactivity of fly ash particles at early ages. Such cements can be grouped under the generic term “hybrid alkaline cements”, where both cement clinker and fly ash, encouraged by the presence of alkalis, are expected to contribute to cementitious gel formation. The work presented here examines some of the durability aspects of high fly ash content hybrid alkaline cement. Specifically, the aspects investigated were: exposure at high temperatures (up to 1000°C, resistance to immersion in aggressive solutions and susceptibility to the alkali aggregate reaction. All tests were repeated with a commercially available sulfate resistant Portland cement for comparison. When exposed to high temperatures, the hybrid alkaline cement showed strikingly different behaviour compared to the control Portland cement, showing fewer micro-cracks and maintaining residual compressive strengths at least equal to original strengths. Beyond 700°C, the hybrid alkaline cement began to sinter, which resulted in shrinkage of around 5% and a 100% increase in residual compressive strengths. No such sintering event was noted in the control Portland cement, which showed a drastic loss in residual compressive strengths upon heating. In immersion tests, the hybrid alkaline cement possessed excellent resistance to sulfate and seawater attack, similar to the control sulfate resistant cement. Both cements were however severely degraded by immersion in 0.1M HCl for 90 days. Both binders complied with the accelerated alkali-aggregate test but when this test was extended, the hybrid alkaline binder showed much greater dimensional stability. Possible reasons for the differences in durability behaviour in both cements

  1. SOLUTIONING

    Directory of Open Access Journals (Sweden)

    Maria de Hoyos Guajardo, Ph.D. Candidate, M.Sc., B.Eng.

    2004-11-01

    Full Text Available The theory that is presented below aims to conceptualise how a group of undergraduate students tackle non-routine mathematical problems during a problem-solving course. The aim of the course is to allow students to experience mathematics as a creative process and to reflect on their own experience. During the course, students are required to produce a written ‘rubric’ of their work, i.e., to document their thoughts as they occur as well as their emotionsduring the process. These ‘rubrics’ were used as the main source of data.Students’ problem-solving processes can be explained as a three-stage process that has been called ‘solutioning’. This process is presented in the six sections below. The first three refer to a common area of concern that can be called‘generating knowledge’. In this way, generating knowledge also includes issues related to ‘key ideas’ and ‘gaining understanding’. The third and the fourth sections refer to ‘generating’ and ‘validating a solution’, respectively. Finally, once solutions are generated and validated, students usually try to improve them further before presenting them as final results. Thus, the last section deals with‘improving a solution’. Although not all students go through all of the stages, it may be said that ‘solutioning’ considers students’ main concerns as they tackle non-routine mathematical problems.

  2. Extraction of gold from Alkaline Cyanide Solution by Alkyl-substituted Secondary Amine%多烷基支链仲胺从碱性氰化液中萃取金

    Institute of Scientific and Technical Information of China (English)

    余建民; 李奇伟; 陈景

    2001-01-01

    研究了多烷基支链仲胺从碱性氰化液中萃取金,考察了平衡时间、水相初始pH值、金浓度、离子强度、温度、萃取剂浓度、稀释剂、相比等因素对金萃取率的影响,绘制了萃取等温线,测定了金的饱和容量,考察了萃取体系对银(Ⅰ)、铁(Ⅱ)、铜(Ⅰ)、镍(Ⅱ)、锌(Ⅱ)的萃取性能,计算出了金与这些杂质元素的分离系数,研究了负载有机相中金的反萃.结果表明,该萃取体系在pH 5~11范围内对Au(cN)2-有较高的萃取率和选择性,pH1/2=11.7,可用于碱性氰化液中金的萃取分离.%The extraction of gold from alkaline cyanide solution by alkyl-substituted secondary aminehas been investigated. The effects of several variables, such as equilibrium time, temperature, dilu-ent, extractant concentration, pH, gold concentration, ionic strength of the aqueous phase and phaseratio (O/A) on the extraction yield are discussed. The extraction isotherm, saturation capacity, sepa-ration coefficients of gold to silver(I), ferrous(Ⅱ), copper( I ), nickel( Ⅱ ), zinc(Ⅱ) have been de-termined respectively. Stripping extraction of gold from loaded organic phase has also been studied.The results showed that the system consisted of 0. 1% (volume fraction) secondary amine (7203)-0. 05%(volume action)ROH-n-dodecane gave high extraction yield and selectivity for Au (CN)2-atpH1/2=11.7.

  3. Determination of sulfur dioxide in traditional Chinese medicine by alkaline solution extraction and ion chromatography%碱性溶液提取-离子色谱法测定中药二氧化硫残留量

    Institute of Scientific and Technical Information of China (English)

    王欣美; 夏晶; 王柯; 季申

    2011-01-01

    目的:建立中药中二氧化硫的测定方法.方法:样品用碱性溶液提取,甲醛作稳定剂,经C18小柱净化.色谱柱为IonPac AS11-HC型离子交换柱,流动相为15 mmol·L-1 KOH,加电自动抑制模式,用配有电导检测器的离子色谱仪测定亚硫酸根.结果:二氧化硫的残留量在1~100 μg线性关系良好,r=0.999 2,检测限为0.53 mg·kg-1,平均回收率为103.7%.结论:该法具有检测时间短、偶然误差小、灵敏度高、操作简便等优点,适于大批中药样品的检测.%Objective; An ion chromatographic method was developed to analyze sulfur dioxide in traditional Chinese medicine (TCM). Method; The samples were extracted with alkaline solution and reacted with formaldehyde to form hydroxymethyl sulfonic acid. The Extracts were cleaned by C,8 column and SO32- was determined with ion chromatography equipped with a conductance detector. In the method, AS11 -HC chromatographic column was used and the mobile phase was 15 mmol ? L-1 KOH. Result; The calibration curve was in good linearity in the range of 1 to 100 μg (r = 0. 999 2). The detection limit was 0. 53 mg ? kg-1 and the average recovery was 103. 7%. Conclusion; The method is simple, sensitive, precise, short-time-consuming, and the random error is smaller, which is applicable to the testing of large quantity batches of TCM.

  4. Characterization of the deviation to the ideality of concentrated actinide and lanthanide salt solutions: contribution of the Bimsa theory; Caracterisation de l'ecart a l'idealite de solutions concentrees de sels d'actinide et de lanthanide: contribution de la theorie Bimsa

    Energy Technology Data Exchange (ETDEWEB)

    Ruas, A

    2006-03-15

    The aim of this work is to describe the mean stoichiometric activity coefficients, osmotic coefficients or water activities of aqueous actinide nitrate salt solutions up to high concentration. These sets of data are required for a better control of the equilibria occurring in liquid-liquid extraction processes. Experimental acquisition of these thermodynamic properties, in the case of some actinide nitrates, is possible and was conducted before.But, many actinide salt solutions cannot be experimentally handled up to high concentration because of unstable oxidation state or very high radioactivity. As a consequence, a suitable predictive theory is necessary for the description of these nitrate salt solutions (such as Am (NO{sub 3}){sub 3}, Cm (NO{sub 3}){sub 3}). The BIMSA ('Binding Mean Spherical Approximation') was chosen for this purpose. This theory, unlike other methods, uses a set of microscopic parameters that have some physical meaning, for the description of macroscopic thermodynamic properties (osmotic coefficients, activity coefficients).The following manuscript is divided by 4 chapters, corresponding to 4 articles accepted in the scientific journal 'Journal of Physical Chemistry'. Chapter 1 first reviews the basic thermodynamic concepts before describing the issues involved in acquiring actinides binary data. An approach based on the thermodynamic concept of simple solutions, the notion of fictive binary data, is described. Within this approach, the activity coefficient of an aqueous phase constituent depends on two parameters: the water activity of the system and total concentration of dissolved constituents. As a first application, new fictive binary data of uranyl nitrate are proposed from measurements on the ternary system UO{sub 2}(NO{sub 3}){sub 2}/HNO{sub 3}/H{sub 2}O.Chapter 2 gives the main principles of the BIMSA theory. It shows also preliminary promising results obtained when modeling lanthanide(III) salt properties. Then

  5. Permeability Modification Using a Reactive Alkaline-Soluble Biopolymer

    Energy Technology Data Exchange (ETDEWEB)

    Snadra L. Fox; X. Xie; K. D. Schaller; E. P. Robertson; G. A. Bala

    2003-10-01

    Polymer injection has been used in reservoirs to alleviate contrasting permeability zones. Current technology relies on the use of cross-linking agents to initiate gelation. The use of biological polymers are advantageous in that they can block high permeability areas, are environmentally friendly, and have potential to form reversible gels without the use of hazardous cross-linkers. Recent efforts at the Idaho National Engineering and Environmental Laboratory (INEEL) have produced a reactive alkaline-soluble biopolymer from Agrobacterium sp. ATCC no. 31749 that gels upon decreasing the pH of the polymeric solution. The focus of this study was to determine the impact an alkaline-soluble biopolymer can have on sandstone permeability. Permeability modification was investigated by injecting solubilized biopolymer into Berea sandstone cores and defining the contribution of pH, salt, temperature, and Schuricht crude oil on biopolymer gelation. The biopolymer was soluble in KOH at a pH greater than 11.4 and gelled when the pH dropped below 10.8. The Berea sandstone core buffered the biopolymer solution, decreasing the pH sufficiently to form a gel, which subsequently decreased the permeability. The effluent pH of the control cores injected with 0.01 {und M} KOH (pH 12.0) and 0.10{und M} KOH (pH 13.0) decreased to 10.6 and 12.7, respectively. The permeability of the sandstone core injected with biopolymer was decreased to greater than 95% of the original permeability at 25 C in the presence of 2% NaCl, and Schuricht crude oil; however, the permeability increased when the temperature of the core was increased to 60 C. Residual resistance factors as high as 792 were seen in Berea cores treated with biopolymer. The buffering capacity of sandstone has been demonstrated to reduce the pH of a biopolymer solution sufficiently to cause the polymer to form a stable in-situ gel. This finding could potentially lead to alternate technology for permeability modification, thus

  6. Titanium corrosion in alkaline hydrogen peroxide environments

    Science.gov (United States)

    Been, Jantje

    1998-12-01

    The corrosion of Grade 2 titanium in alkaline hydrogen peroxide environments has been studied by weight loss corrosion tests, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) measurements and potentiodynamic polarography. Calcium ions and wood pulp were investigated as corrosion inhibitors. In alkaline peroxide, the titanium corrosion rate increased with increasing pH, temperature, and hydrogen peroxide concentration. The corrosion controlling mechanism is thought to be the reaction of the oxide with the perhydroxyl ion. No evidence of thermodynamically stable calcium titanate was found in the surface film of test coupons exposed to calcium-inhibited alkaline peroxide solutions. Calcium inhibition is probably the result of low local alkali and peroxide concentrations at the metal surface produced by reaction of adsorbed calcium with hydrogen peroxide. It has been shown that the inhibiting effect of calcium is temporary, possibly through an effect of calcium on the chemical and/or physical stability of the surface oxide. Pulp is an effective and stable corrosion inhibitor. Raising the pulp concentration decreased the corrosion rate. The inhibiting effect of pulp may be related to the adsorption and interaction of the pulp fibers with H 2O2, thereby decreasing the peroxide concentration and rendering the solution less corrosive. The presence of both pulp and calcium led to higher corrosion rates than obtained by either one inhibitor alone. Replacement of hydrofluoric acid with alkaline peroxide for pickling of titanium was investigated. Titanium corrosion rates in alkaline peroxide exceeded those obtained in the conventional hydrofluoric acid bath. General corrosion was observed with extensive roughening of the surface giving a dull gray appearance. Preferred dissolution of certain crystallographic planes was investigated through the corrosion of a titanium single crystal. Whereas the overall effect on the corrosion rate was small

  7. THE IMPACT OF DISSOLVED SALTS ON PASTES CONTAINING FLY ASH, CEMENT AND SLAG

    Energy Technology Data Exchange (ETDEWEB)

    Harbour, J.; Edwards, T.; Williams, V.

    2009-09-21

    The degree of hydration of a mixture of cementitious materials (Class F fly ash, blast furnace slag and portland cement) in highly concentrated alkaline salt solutions is enhanced by the addition of aluminate to the salt solution. This increase in the degree of hydration, as monitored with isothermal calorimetry, leads to higher values of dynamic Young's modulus and compressive strength and lower values of total porosity. This enhancement in performance properties of these cementitious waste forms by increased hydration is beneficial to the retention of the radionuclides that are also present in the salt solution. The aluminate ions in the solution act first to retard the set time of the mix but then enhance the hydration reactions following the induction period. In fact, the aluminate ions increase the degree of hydration by {approx}35% over the degree of hydration for the same mix with a lower aluminate concentration. An increase in the blast furnace slag concentration and a decrease in the water to cementitious materials ratio produced mixes with higher values of Young's modulus and lower values of total porosity. Therefore, these operational factors can be fine tuned to enhance performance properties of cementitious waste form. Empirical models for Young modulus, heat of hydration and total porosity were developed to predict the values of these properties. These linear models used only statistically significant compositional and operational factors and provided insight into those factors that control these properties.

  8. Study on air electrode Co-N/C electrocatalyst for oxygen reduction reaction in alkaline solution%碱性溶液中空气电极催化剂Co-N/C的研究

    Institute of Scientific and Technical Information of China (English)

    蒋明莉; 陈昌国; 司玉军; 郭朝中; 尹伟

    2013-01-01

    采用简单热处理方式制备了空气电极用氧还原电催化剂Co-N/C(800),利用线性电位扫描、控电流极化曲线及单电池测试等方法评价Co-N/C (800)的氧还原反应(ORR)催化活性.结果表明:该催化剂在碱性溶液中(1 mol/LNaOH)对ORR有很好的催化活性,起始氧还原电位约为0.04 V(vs.Hg/HgO);在室温及空气气氛条件下,以Co-N/C(800)制备的空气电极在7mol/L NaOH溶液中时性能最佳,在电极电位为-0.6V(vs.Hg/HgO)时电流密度达100 mA/cm2;自制的空气电极与纯锌片所组装的锌-空气电池,以7 mol/L NaOH为电解液,在电池过电位为0.8V时,电流密度超过了100 mA/cm2,催化性能优于常规MnO2催化剂;同时进行了单电池放电测试,放电平台保持在1.25 ~1.30 V且性能稳定.%A non-noble metal oxygen reduction reaction(ORR) catalyst labeled as Co-N/C (800) was prepared by heat-treatment process. The electrocatalytic activity to ORR was investigated in alkaline solution by linear sweep voltammetric curves, polarization curves, as well as single fuel cell tests. The results show that the catalytic activity of Co-N/C (800) to ORR is good with an onset potential of 0.04 V(vs. Hg/HgO). Besides,a current density of 100mA/cm2at-0. 6 V(vs. Hg/HgO)could be obtained on the air-electrode using Co-N/C (800) as an electrocatalyst in 7 mol/L NaOH solution on the condition of room temperature and air atmosphere. The negative electrode of pure zinc and the electrolyte 7 mol/L NaOH were selected in the zinc-air cell,and the current density exceeds 100mA/cm2 at 0. 8 V,which is superior to MnO2 catalyst More importantly,the results of single cell test indicated that the cell discharge voltage remain at 1.25 V~1. 30 V and the performance is very stable.

  9. Salt cookbook

    CERN Document Server

    Saha, Anirban

    2015-01-01

    If you are a professional associated with system and infrastructure management, looking at automated infrastructure and deployments, then this book is for you. No prior experience of Salt is required.

  10. Phosphate salts

    Science.gov (United States)

    ... levels that are too high, and for preventing kidney stones. They are also taken for treating osteomalacia (often ... But intravenous phosphate salts should not be used. Kidney stones (nephrolithiasis). Taking potassium phosphate by mouth might help ...

  11. Anion- interactions in layered structures of salts of 5-(hydroxyimino) quinolin-8-one and related salts

    Indian Academy of Sciences (India)

    Prithiviraj Khakhlary; Jubaraj B Baruah

    2015-01-01

    Relevance of anion- interactions in chloride, bromide, nitrate and perchlorate salts of 5-(hydroxyimino)quinolin-8-one are discussed. Structures of nitrate salt of 5-aminoquinoline as well as nitrate salt of 4-hydroxyquinazoline are compared with the structure of nitrate salt of 5-(hydroxyimino)quinolin-8-one. From such a comparison, two different arrangements of nitrate ions with respect to the respective cations are discerned. Nitrate ions are sandwiched between aromatic planes of cations in nitrate salts of 5-(hydroxyimino)quinolin-8-one or 4-hydroxyquinazoline; whereas, nitrate ions are in oblique positions with respect to aromatic planes of counter cations in nitrate salt of 5-aminoquinoline. Binding constants of different nitrate salts in solution are determined by UV-visible spectroscopic titrations. Solution study shows formation of ion-pairs of these salts in solution.

  12. Solid-state materials for anion sensing in aqueous solution: highly selective colorimetric and luminescence-based detection of perchlorate using a platinum(II) salt.

    Science.gov (United States)

    Taylor, Stephen D; Howard, Whitney; Kaval, Necati; Hart, Robert; Krause, Jeanette A; Connick, William B

    2010-02-21

    The PF(6)(-) salt of a platinum(II) complex changes from yellow to red and becomes intensely luminescent upon exposure to aqueous ClO(4)(-). The response is remarkably selective. Spectroscopic changes are consistent with anion exchange resulting in shortening of the intramolecular PtPt distances between the square planar cations.

  13. Solid-state materials for anion sensing in aqueous solution: highly selective colorimetric and luminescence-based detection of perchlorate using a platinum(II) salt

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Stephen D.; Howard, Whitney; Kaval, Necati; Hart, Robert; Krause, Jeanette A.; Connick, William B. (UCIN); (Shepherd)

    2010-07-23

    The PF{sub 6}{sup -} salt of a platinum(II) complex changes from yellow to red and becomes intensely luminescent upon exposure to aqueous ClO{sub 4}{sup -}. The response is remarkably selective. Spectroscopic changes are consistent with anion exchange resulting in shortening of the intramolecular Pt***Pt distances between the square planar cations.

  14. Alkaline and ultrasound assisted alkaline pretreatment for intensification of delignification process from sustainable raw-material.

    Science.gov (United States)

    Subhedar, Preeti B; Gogate, Parag R

    2014-01-01

    Alkaline and ultrasound-assisted alkaline pretreatment under mild operating conditions have been investigated for intensification of delignification. The effect of NaOH concentration, biomass loading, temperature, ultrasonic power and duty cycle on the delignification has been studied. Most favorable conditions for only alkaline pretreatment were alkali concentration of 1.75 N, solid loading of 0.8% (w/v), temperature of 353 K and pretreatment time of 6 h and under these conditions, 40.2% delignification was obtained. In case of ultrasound-assisted alkaline approach, most favorable conditions obtained were alkali concentration of 1N, paper loading of 0.5% (w/v), sonication power of 100 W, duty cycle of 80% and pretreatment time of 70 min and the delignification obtained in ultrasound-assisted alkaline approach under these conditions was 80%. The material samples were characterized by FTIR, SEM, XRD and TGA technique. The lignin was recovered from solution by precipitation method and was characterized by FTIR, GPC and TGA technique.

  15. Formulating poultry processing sanitizers from alkaline salts of fatty acids

    Science.gov (United States)

    Though some poultry processing operations remove microorganisms from carcasses; other processing operations cause cross-contamination that spreads microorganisms between carcasses, processing water, and processing equipment. One method used by commercial poultry processors to reduce microbial contam...

  16. 14N NQR and phase transitions in tetracyanoquinodimethanide alkaline salts

    Science.gov (United States)

    Ambrosetti, R.; Angelone, R.; Colligiani, A.; Murgich, J.

    1983-12-01

    14N NQR lines of RbTCNQ and NaTCNQ polycrystalline samples, measured as a function of temperature, show small but sharp discontinuities at the regular-alternant phase transition (found respectively at 214 K and 346 K), together with the expected change in spectral multiplicity. No ν - lines were detected in NaTCNQ. Co-existence of phases, more marked in NaTCNQ, shows up in NQR data. The use of a pulsed, FT spectrometer yields estimates of T 1 relaxation time: it shows no discontinuity at the phase transition, is around 1 ms at room temperature for ν+ lines, more than 2 order of magnitudes larger for ν - lines, increases smoothly on decreasing temperature.

  17. Experimental study of evaporation of distilled water and 10% NaCl and СaCl2 aqueous salt solutions droplets under their free falling on a heated surface

    Directory of Open Access Journals (Sweden)

    Feoktistov D.V.

    2017-01-01

    Full Text Available The paper presents the experimental results of evaporation of distilled water and 10% aqueous salt solutions of NaCl and СaCl2 droplets under their free falling on a heated surface. It is proved that it is more expedient to conduct the experimental research in this field according to classical multifactorial experiment. Laser treatment of surfaces is found to increase the evaporation rate and to biases the point of boiling crisis in the region of lower surface temperatures. In this case, in the conditions of boiling crisis the frequency of contact of a droplet with a heated surface will decrease.

  18. Facile Synthesis of Gold Nanoflowers in a Polyvinyl Pyrrolidone Alkaline Aqueous Solution%聚乙烯吡咯烷酮碱性水溶液中金纳米花的简易合成

    Institute of Scientific and Technical Information of China (English)

    任月萍; 徐程程; 方云

    2011-01-01

    Three-dimensional (3D) gold nanoflowers of 60-80 nm in diameter were successfully synthesized using polyvinyl pyrrolidone (PVP) as both a protecting agent and a reducing agent in alkaline aqueous solutions.Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images revealed that many antennae of 10-15 nm existed on their surfaces.X-ray diffraction (XRD) pattern suggested face-centered cubic (fcc) structures for these gold nanoflowers.The selected area electron diffraction (SAED) pattern of a single gold nanoflower indicated polycrystal characteristics.We found that there were three key stages in the growth of the gold nanoflowers: primary nanocrystals agglomerated to form multipod-like nanoparticles, and then the multipod-like nanoparticles aggregated into loose flower-like nanoparticles that ultimately grew into compact gold nanoflowers through Ostwald ripening.During the synthesis of gold nanoflowers, the molar ratios of PVP/HAuCl4 at fixed HAuCl4 and NaOH concentrations mostly influenced the morphologies of the final products.Therefore, a proper molar ratio of PVP/HAuCl4 and a suitable NaOH concentration were essential for the synthesis of typical gold nanoflowers with controlled sizes and antenna architectures.%以聚乙烯吡咯烷酮PVP)兼作保护剂和还原剂在碱性水溶液中直接还原HAuCl4制备出了60-80 nm的三维(3D)金纳米花.产物的透射电子显微镜(TEM)和扫描电子显微镜(SEM)图像显示,金纳米花表面布满10-15 nm左右的纳米触角,X射线衍射(XRD)表征揭示产物为金的面心立方晶体,选区电子衍射(SAED)花样说明金纳米花为多晶结构.金纳米花的生长经历了三个关键步骤,即初级纳米晶聚集成多脚状纳米粒子,随后在合适的PVP/HAuCl4浓度比及NaOH浓度下,多脚状纳米粒子进一步聚集形成疏松的花状粒子,最终经过Ostwald熟化形成致密的花状产物.一定HAuCl4浓度下PVP/HAuCl4浓度比和NaOH浓度对产

  19. Preparation of nano-copper conductive adhesive from spent PCB alkaline etching solution%利用PCB碱性蚀刻废液制备纳米铜导电胶

    Institute of Scientific and Technical Information of China (English)

    罗小虎; 陈世荣; 张玉婷; 汪浩; 谢金平; 吴耀程; 梁韵锐

    2013-01-01

    以碱性蚀刻废液为原料,采用液相还原法制备了纳米铜粉,将制备的纳米铜粉作为导电填充料添加到环氧树脂中制备出纳米铜导电胶。研究了纳米二氧化硅、硅烷偶联剂KH570和纳米铜粉的添加量对导电胶剪切强度以及纳米铜粉添加量对导电胶体积电阻率的影响,探讨了环氧树脂与固化剂聚酰胺适宜的反应时间。实验结果表明,所制备的铜粉为球状,粒径在40~100 nm之间;当环氧树脂与固化剂聚酰胺树脂650的质量比为4∶1,纳米二氧化硅、硅烷偶联剂和纳米铜粉的加入量分别占环氧树脂-聚酰胺树脂体系质量的1.5%、4.0%和70%时,在90°C下固化1.0 h,可以制备出体积电阻率为3.05×10−3Ω·cm、剪切强度达8.04 MPa的导电胶。%Cu nanoparticles were obtained from spent alkaline etching solution using liquid phase reduction method, and then added as conductive filler to epoxy resin to prepare a nano-copper conductive adhesive. The effect of the amounts of nano-SiO2, silane coupling agent KH570 and Cu nanoparticles on the shear strength of conductive adhesive and the effect of Cu nanoparticle dosage on bulk resistivity of the conductive adhesive were studied. The optimal reaction time of epoxy resin with polyamide curing agent was discussed. The prepared Cu particles are spherical with a size of 40-100 nm. The conductive adhesive with a bulk resistivity of 3.05 × 10−3Ω·cm and a shear strength 8.04 MPa can be obtained by curing the epoxy/polyamide resin system with a mass ratio of epoxy resin to polyamide resin 650 equal to 4:1 containing 1.5wt% nano-SiO2, 4.0wt% silane coupling, and 70wt% Cu nanoparticles (all of the mass fractions are relative to the total mass of the epoxy/polyamide resin system) at 90 °C for 1.0 h.

  20. Electrocatalytic Oxidation of Cellulose to Gluconate on Carbon Aerogel Supported Gold Nanoparticles Anode in Alkaline Medium

    Directory of Open Access Journals (Sweden)

    Hanshuang Xiao

    2015-12-01

    Full Text Available The development of high efficient and low energy consumption approaches for the transformation of cellulose is of high significance for a sustainable production of high value-added feedstocks. Herein, electrocatalytic oxidation technique was employed for the selective conversion of cellulose to gluconate in alkaline medium by using concentrated HNO3 pretreated carbon aerogel (CA supported Au nanoparticles as anode. Results show that a high gluconate yield of 67.8% and sum salts yield of 88.9% can be obtained after 18 h of electrolysis. The high conversion of cellulose and high selectivity to gluconate could be attributed to the good dissolution of cellulose in NaOH solution which promotes its hydrolysis, the surface oxidized CA support and Au nanoparticles catalyst which possesses high amount of active sites. Moreover, the bubbled air also plays important role in the enhancement of cellulose electrocatalytic conversion efficiency. Lastly, a probable mechanism for electrocatalytic oxidation of cellulose to gluconate in alkaline medium was also proposed.

  1. Results Of Routine Strip Effluent Hold Tank, Decontaminated Salt Solution Hold Tank, Caustic Wash Tank And Caustic Storage Tank Samples From Modular Caustic-Side Solvent Extraction Unit During Macrobatch 6 Operations

    Energy Technology Data Exchange (ETDEWEB)

    Peters, T. B.

    2014-01-02

    Strip Effluent Hold Tank (SEHT), Decontaminated Salt Solution Hold Tank (DSSHT), Caustic Wash Tank (CWT) and Caustic Storage Tank (CST) samples from the Interim Salt Disposition Project (ISDP) Salt Batch (“Macrobatch”) 6 have been analyzed for 238Pu, 90Sr, 137Cs, and by Inductively Coupled Plasma Emission Spectroscopy (ICPES). The Pu, Sr, and Cs results from the current Macrobatch 6 samples are similar to those from comparable samples in previous Macrobatch 5. In addition the SEHT and DSSHT heel samples (i.e. ‘preliminary’) have been analyzed and reported to meet NGS Demonstration Plan requirements. From a bulk chemical point of view, the ICPES results do not vary considerably between this and the previous samples. The titanium results in the DSSHT samples continue to indicate the presence of Ti, when the feed material does not have detectable levels. This most likely indicates that leaching of Ti from MST has increased in ARP at the higher free hydroxide concentrations in the current feed.

  2. Study of sulfur adlayers on Au(1 1 1) from basic hydrolysis of piperazine bis(dithiocarbamate) sodium salt

    Science.gov (United States)

    Martínez, Javier A.; Valenzuela, José; Hernandez-Tamargo, Carlos E.; Cao-Milán, Roberto; Herrera, José A.; Díaz, Jesús A.; Farías, Mario H.; Mikosch, Hans; Hernández, Mayra P.

    2015-08-01

    Sulfur adlayers on Au(1 1 1) were obtained after the interaction of a gold substrate with an alkaline solution of piperazine bis(dithiocarbamate) sodium salt. Characterization of the sulfur modified gold surface was performed by means of X-Ray Photoelectron Spectroscopy (XPS), Scanning Tunneling Microscopy (STM) and Density Functional Theory (DFT) calculations. XPS signals indicated the presence of S-Au bonds, monomeric and polymeric sulfur, and absence of nitrogen and sodium. Images from STM showed the formation of quasi-rectangular octomers in coexistence with another phase. A DFT model using the arrangement of sulfur dimers on the Au(1 1 1) surface effectively reproduced the experimental STM images.

  3. 表面活性剂从碱性氰化液中萃取金的微观机理研究(Ⅰ):萃取体系的优化%The Micromechanism of Extracting Gold from Alkaline Cyanide Solution with Surfactants(Ⅰ):The Optimization of Extraction System

    Institute of Scientific and Technical Information of China (English)

    余建民; 李奇伟; 陈景

    2001-01-01

    系统研究了含氧、含磷、含氮及含硫类萃取剂分别在水相中加入及不加入典型表面活性剂的2种情况下,对Au(CN)-2的萃取性能,优选出了适宜的萃取体系。%Extracting gold with extractants containing oxgen,phosphorus,nitrogan or suphur from alkaline cyanide solution with or without typical surfactants has been extensively studied.The optimum extraction system is also given in the present paper.

  4. Multi-Scale Modeling of the Effects of Salt and Perfume Raw Materials on the Rheological Properties of Commercial Thread-like Micellar Solutions.

    Science.gov (United States)

    Tang, Xueming; Zou, Weizhong; Koenig, Peter H; McConaughy, Shawn D; Weaver, Michael R; Eike, David Michael; Schmidt, Michael J; Larson, Ronald G

    2017-02-22

    We link micellar structures to rheological properties for two surfactant body-wash formulations at various concentrations of salts and perfume raw materials (PRMs) using molecular simulations and micellar-scale modeling as well as traditional surfactant packing arguments. The two body washes, named BW-1EO and BW-3EO, are composed of sodium lauryl ethylene glycol ether sulfate (SLEnS, where n is the average number of ethylene glycol repeat units), cocamidopropyl betaine (CAPB), ACCORD (which is a mixture of six PRMs), and NaCl salt. BW-3EO is an SLE3S-based body-wash, whereas BW-1EO is an SLE1S-based body-wash. Additional PRMs are also added into the body-washes. The effects of temperature, salt and added PRMs on micellar lengths, breakage times, end-cap free energies, and other properties are obtained from fits of rheological data to predictions of the "Pointer Algorithm" (Zou and Larson, J. Rheol. 2014, 58, 1-41), which is a simulation method based on the Cates model of micellar dynamics. Changes of these micellar properties are interpreted using the Israelachvili surfactant packing argument. From coarse-grained molecular simulations we infer how salt modifies the micellar properties by changing the packing between the surfactant head groups, with the micellar radius remaining nearly constant. PRMs do so by partitioning to different locations within the micelles according to their octanol/water partition coefficient POW and chemical structures, adjusting the packing of head and/or tail groups, and by changing the micelle radius, in the case of a large hydrophobic PRM. We find that relatively hydrophilic PRMs with log⁡POW 4 are isolated, deep inside the micelle, separating from the tails and swelling the radius of the micelle, leading to shorter micelles and much lower viscosities, leading eventually to swollen-droplet micelles.

  5. Solution- and solid-state conformations of C(α)-alkyl analogues of methylphenidate (Ritalin) salts: avoidance of gauche(+)gauche(-) interactions.

    Science.gov (United States)

    Steinberg, Avital; Froimowitz, Mark; Parrish, Damon A; Deschamps, Jeffrey R; Glaser, Robert

    2011-11-18

    Alkyl analogues of methylphenidate (Ritalin) salts are slow onset, long duration dopamine reuptake inhibitors with a potential use as a cocaine abuse pharmacotherapy. X-ray crystallographic studies and nuclear magnetic resonance (NMR) investigations strongly suggest that avoidance of sterically unfavorable gauche(-)gauche(+) orientations effectively influences both the C(α)-alkyl side chain conformation and the formation of a predominant rotamer about the CH-CH bond ligating piperidine and C(Ar)R moieties. The favored CH-CH rotamer in D(2)O and in CD(2)Cl(2) of the pharmacologically interesting i-Bu and CH(2)-cyc-Pnt (RS,RS)-salts has the same antiperiplanar arrangement that was found in the crystal structures, although there clearly is a fast equilibrium involving smaller amounts of synclinal partners. While the rotamer in the (RS,SR)-i-Bu HCl crystal structure exhibits a synclinal orientation for the vicinal pair of adjacent methine protons, the weighted time-averaged arrangement for these protons becomes almost completely antiperiplanar when the crystals are dissolved in D(2)O. Increased steric congestion around the CH-CH bond in the analogous N-methyl tertiary ammonium salts seems to augment the quantity of the preferred rotamer within the mixture. The stereochemistry of the species observed via NMR seems to arise from specific combinations of N-methyl orientation and avoidance of sterically unfavorable gauche(-)gauche(+) arrangements.

  6. An alkaline element

    Energy Technology Data Exchange (ETDEWEB)

    Arita, T.; Murakami, K.; Okha, K.

    1983-04-28

    A cathode with a dual layer active mass is installed in the disk shaped alkaline silver and zinc element. The first layer, which is turned towards the anode, contains 85 parts Ag2O, 5 parts electrolytic MnO2 and 10 parts graphite. The second layer, which contacts the bottom of the element, contains 35 parts Ag2O, 60 parts electrolytic MnO2 and 5 parts graphite. The electrical capacity of the first and second layers is 60 and 40, respectively. The first layer may be discharged with a high current density and the second layer with less current density. The element has high characteristics with comparatively low cost.

  7. Batch and column adsorption of herbicide fluroxypyr on different types of activated carbons from water with varied degrees of hardness and alkalinity.

    Science.gov (United States)

    Pastrana-Martínez, L M; López-Ramón, M V; Fontecha-Cámara, M A; Moreno-Castilla, C

    2010-02-01

    There has been little research into the effects of the water hardness and alkalinity of surface waters on the adsorption of herbicides on activated carbons. The aim of this study was to determine the influence of these water characteristics on fluroxypyr adsorption on different activated carbons. At low fluroxypyr surface concentrations, the amount adsorbed from distilled water was related to the surface hydrophobicity. Surface area of carbons covered by fluroxypyr molecules ranged from 60 to 65%. Variations in fluroxypyr solubility with water hardness and alkalinity showed a salting-in effect. Calcium, magnesium and bicarbonate ions were adsorbed to a varied extent on the activated carbons. The presence of fluroxypyr in solution decreased their adsorption due to a competition effect. K(F) from the Freundlich equation linearly increased with water hardness due to salt-screened electrostatic repulsions between charged fluroxypyr molecules. The amount adsorbed from distilled water was largest at high fluroxypyr solution concentrations, because there was no competition between inorganic ions and fluroxypyr molecules. The column breakthrough volume and the amount adsorbed at breakthrough were smaller in tap versus distilled water. Carbon consumption was lower with activated carbon cloth than with the use of granular activated carbon.

  8. Titratable Acidity and Alkalinity of Red Soil Surfaces

    Institute of Scientific and Technical Information of China (English)

    SHAOZONG-CHEN; HEQUN; 等

    1993-01-01

    The surfaces of red soils have an apparent amphoteric character,carrying titratable acidity and titratable alkalinity simultaneously.The titratable acidity arises from deprotonation of hydroxyl groups of hydrous oxide-type surfaces and dissociation of weak-acid functional groups of soil organic matter,while the titratable alkalinity is derived from release of hydroxyl groups of hydrous oxide-type surfaces.The titratable acidity and titratable alkalinity mainly depended on the composition and content of iron and aluminum oxides in the soils.The results showed that the titratable acidity and titratable alkalinity were in significantly positive correlation not only with the content of amorphous aluminum oxide(Alo) and iron oxide(Feo) extracted with acid ammonium oxalate solution,free iron oxide(Fed) extracted with sodium dithionite-citrate-bicarbonate(DCB) and clays,but also with the zero point of charge (ZPC) of the samples.Organic matter made an important contribution to the titratable acidity.the titratable alkalinity was closely correlated with the amount of fluoride ions adsorbed.The titratable acidity and titratable alkalinity of red soils were influenced by parent materials,being in the order of red soil derived from basalt> that from tuff> that from granite.The titratable acidity and titratable alkalinity ware closely related with origination of the variable charges of red soils,and to a certain extent were responsible for variable negative and positive charges of the soils.

  9. Cation exchange properties of zeolites in hyper alkaline aqueous media.

    Science.gov (United States)

    Van Tendeloo, Leen; de Blochouse, Benny; Dom, Dirk; Vancluysen, Jacqueline; Snellings, Ruben; Martens, Johan A; Kirschhock, Christine E A; Maes, André; Breynaert, Eric

    2015-02-03

    Construction of multibarrier concrete based waste disposal sites and management of alkaline mine drainage water requires cation exchangers combining excellent sorption properties with a high stability and predictable performance in hyper alkaline media. Though highly selective organic cation exchange resins have been developed for most pollutants, they can serve as a growth medium for bacterial proliferation, impairing their long-term stability and introducing unpredictable parameters into the evolution of the system. Zeolites represent a family of inorganic cation exchangers, which naturally occur in hyper alkaline conditions and cannot serve as an electron donor or carbon source for microbial proliferation. Despite their successful application as industrial cation exchangers under near neutral conditions, their performance in hyper alkaline, saline water remains highly undocumented. Using Cs(+) as a benchmark element, this study aims to assess the long-term cation exchange performance of zeolites in concrete derived aqueous solutions. Comparison of their exchange properties in alkaline media with data obtained in near neutral solutions demonstrated that the cation exchange selectivity remains unaffected by the increased hydroxyl concentration; the cation exchange capacity did however show an unexpected increase in hyper alkaline media.

  10. COUPLING THE ALKALINE-SURFACTANT-POLYMER TECHNOLOGY AND THE GELATION TECHNOLOGY TO MAXIMIZE OIL PRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm Pitts; Jie Qui; Dan Wilson; Phil Dowling

    2004-05-01

    Gelation technologies have been developed to provide more efficient vertical sweep efficiencies for flooding naturally fractured oil reservoirs or more efficient areal sweep efficiency those with high permeability contrast ''thief zones''. The field proven alkaline-surfactant-polymer technology economically recovers 15% to 25% OOIP more oil than waterflooding in the swept pore space of an oil reservoir. However, alkaline-surfactant-polymer technology is not amenable to the naturally fractured reservoirs or those with thief zones because much of the injected solution bypasses the target pore space containing oil. The objective of this work is to investigate whether combining these two technologies could broaden the applicability of alkaline-surfactant-polymer flooding into these reservoirs. Fluid-fluid interaction with different gel chemical compositions and alkaline-surfactant-polymer solution with pH values ranging from 9.2 to 12.9 have been tested. Aluminum-polyacrylamide gels are not stable to alkaline-surfactant-polymer solutions at any pH. Chromium--polyacrylamide gels with polymer to chromium ion ratios of 25 or greater were stable to alkaline-surfactant-polymer solutions if solution pH was 10.6 or less. When the polymer to chromium ion was 15 or less, chromium-polyacrylamide gels were stable to alkaline-surfactant-polymer solutions with pH values up to 12.9. Chromium-xanthan gum gels were stable to alkaline-surfactant-polymer solutions with pH values of 12.9 at the polymer to chromium ion ratios tested. Silicate-polyacrylamide, resorcinol-formaldehyde, and sulfomethylated resorcinol-formaldehyde gels were also stable to alkaline-surfactant-polymer solutions with pH values ranging from 9.2 to 12.9. Iron-polyacrylamide gels were immediately destroyed when contacted with any of the alkaline-surfactant-polymer solutions with pH values of 9.2 to 12.9.

  11. Construction and application of recombinant strain for the production of an alkaline protease from Bacillus licheniformis.

    Science.gov (United States)

    Lin, Songyi; Zhang, Meishuo; Liu, Jingbo; Jones, Gregory S

    2015-03-01

    The alkaline protease gene, Apr, from Bacillus licheniformis 2709 was cloned into an expression vector pET - 28b (+), to yield the recombinant plasmid pET-28b (+) - Apr. The pET-28b (+) - Apr was expressed in a high expression strain E. coli BL21. The amino acid sequence deduced from the DNA sequence analysis revealed a 98% identity to that of Bacillus licheniformis 2709. Sodium salt-Polyacrylamide gel electrophoresis (SDS-PAGE) was used to access the protein expression. SDS-PAGE analysis indicated a protein of Mr of 38.8 kDa. The medium components and condition of incubation were optimized for the growth state of a recombinant strain. The optimal composition of production medium was composed of glucose 8 g/L, peptone 8 g/L and salt solution 10 mL. The samples were incubated on a rotary shaker of 180 r/min at 37°C for 24 h.

  12. Removing tannins from medicinal plant extracts using an alkaline ethanol precipitation process: a case study of Danshen injection.

    Science.gov (United States)

    Gong, Xingchu; Li, Yao; Qu, Haibin

    2014-11-14

    The alkaline ethanol precipitation process is investigated as an example of a technique for the removal of tannins extracted from Salviae miltiorrhizae Radix et Rhizoma for the manufacture of Danshen injection. More than 90% of the tannins can be removed. However, the recoveries of danshensu, rosmarinic acid, and salvianolic acid B were less than 60%. Total tannin removal increased as the refrigeration temperature decreased or the amount of NaOH solution added increased. Phenolic compound recoveries increased as refrigeration temperature increased or the amount of NaOH solution added decreased. When operated at a low refrigeration temperature, a relative high separation selectivity can be realized. Phenolic compound losses and tannin removal were mainly caused by precipitation. The formation of phenol salts, whose solubility is small in the mixture of ethanol and water used, is probably the reason for the precipitation. A model considering dissociation equilibrium and dissolution equilibrium was established. Satisfactory correlation results were obtained for phenolic compound recoveries and total tannin removal. Two important parameters in the model, which are the water content and pH value of alkaline supernatant, are suggested to be monitored and controlled to obtain high batch-to-batch consistency.

  13. Combination of alkaline phosphatase anti-alkaline phosphatase (APAAP)- and avidin-biotin-alkaline phosphatase complex (ABAP)-techniques for amplification of immunocytochemical staining of human testicular tissue.

    Science.gov (United States)

    Davidoff, M S; Schulze, W; Holstein, A F

    1991-01-01

    An amplification procedure was developed for the visualization of antigens in human testis using monoclonal antibodies against desmin and vimentin. The technique combines the high sensitive and specific APAAP- and ABAP-methods. Depending on the quality of the antibodies used and the processing of the material prior to the immunocytochemical staining the amplification technique may be applied either as a single APAAP and ABAP- or as a double APAAP and ABAP-combination. Especially after the double amplification reaction a distinct increase of the staining intensity of the vimentin- (in Sertoli cells, myofibroblasts of the lamina propria, and fibroblasts of the interstitium) and desmin- (in myofibroblasts of the lamina propria and smooth muscle cells of the blood vessels) like immunoreactivity was observed. If different diazonium salts were used for the visualization of the alkaline phosphatase activity (e.g. Fast Red TR Salt, Fast Blue BB Salt) desmin- and vimentin-like immunoreactivity can be demonstrated in the same tissue section in a double sequential staining approach. For double staining, the alkaline phosphatase technique may be combined successfully with a technique or a combination that uses peroxidase as a marker.

  14. Mechanism for salt scaling

    Science.gov (United States)

    Valenza, John J., II

    Salt scaling is superficial damage caused by freezing a saline solution on the surface of a cementitious body. The damage consists of the removal of small chips or flakes of binder. The discovery of this phenomenon in the early 1950's prompted hundreds of experimental studies, which clearly elucidated the characteristics of this damage. In particular it was shown that a pessimum salt concentration exists, where a moderate salt concentration (˜3%) results in the most damage. Despite the numerous studies, the mechanism responsible for salt scaling has not been identified. In this work it is shown that salt scaling is a result of the large thermal expansion mismatch between ice and the cementitious body, and that the mechanism responsible for damage is analogous to glue-spalling. When ice forms on a cementitious body a bi-material composite is formed. The thermal expansion coefficient of the ice is ˜5 times that of the underlying body, so when the temperature of the composite is lowered below the melting point, the ice goes into tension. Once this stress exceeds the strength of the ice, cracks initiate in the ice and propagate into the surface of the cementitious body, removing a flake of material. The glue-spall mechanism accounts for all of the characteristics of salt scaling. In particular, a theoretical analysis is presented which shows that the pessimum concentration is a consequence of the effect of brine pockets on the mechanical properties of ice, and that the damage morphology is accounted for by fracture mechanics. Finally, empirical evidence is presented that proves that the glue-small mechanism is the primary cause of salt scaling. The primary experimental tool used in this study is a novel warping experiment, where a pool of liquid is formed on top of a thin (˜3 mm) plate of cement paste. Stresses in the plate, including thermal expansion mismatch, result in warping of the plate, which is easily detected. This technique revealed the existence of

  15. Electric battery cell, system and method. [ambient temperature, dithionite salt in electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, R.E.

    1979-05-15

    An ambient-temperature electric cell of primary and secondary nature, characterized by the use of the dithionite salt of an active (alkali or an alkaline earth) metal as the charging agent, is described along with processes for manufacturing and for operating it. The dithionite salt is dissolved and suspended in an anhydrous electrolyte comprised of a suitable solvent, which may also contain another salt of the same active metal and may be saturated with sulfur dioxide. To form the cell, a sealed and evacuated enclosure having a negative electrode and a positive current-gathering electrode is filled with the electrolyte and subjected to a charging current sufficient to plate the active metal onto the negative electrode, while the positive electrode is saturated with sulfur dioxide. In the case of a secondary cell, the dithionite produced upon discharge is available as a partially dissolved and suspended salt in the electrolyte. Such availability may be enhanced by a system for forced circulation of the electrolyte. In the case of a primary cell, the final cell potential and discharge characteristics may be enhanced by replacing the dithionite electrolyte with other anhydrous electrolyte solutions (e.g., sulfuryl chloride or thionyl chloride) once the lithium has been plated out. The cell is characterized by extremely low internal resistance, long shelf life, and excellent performance over a wide temperature range. 72 claims.

  16. Effects of Saline and Alkaline Stresses on Growth and Physiological Changes in Oat (Avena sativa L. Seedlings

    Directory of Open Access Journals (Sweden)

    Zhanwu GAO

    2014-12-01

    Full Text Available Two neutral salts (NaCl and Na2SO4 and alkaline salts (NaHCO3 and Na2CO3 were both mixed in 2:1 ratio, and the effects of saline and alkaline stresses on growth and physiological changes in oat seedlings were explored. Result showed that biomass, water content and chlorophyll content decreased while cell membrane permeability significantly increased under alkaline stress. Saline stress did not have obvious effect on pH value in tissue fluids of shoot and root, but alkaline stress increased pH value in root tissue fluid. The contents of Na+, Na+/K+, SO42- increased more, and K+, NO3-,H2PO4- decreased more under alkaline stress, the Cl- content increased obviously under saline stress but had little change under alkaline stress. The increments of proline and organic acid were both greater under alkaline stress, but organic acid content kept the same level under saline stress. Alkaline stress caused more harmful effects on growth and physiological changes in oat seedlings especially broke the pH stability in root tissue fluid. Physiological adaptive mechanisms of oat seedlings under saline stress and alkaline stress were different, which mainly took the way of accumulating organic acid under alkali stress but accumulating Cl- under saline stress.

  17. Influence of Bayer Red-mud on the Alkalinity of Cement-based Material Pore Solution and the Strength Development%拜耳法赤泥对水泥浆体孔溶液碱度及强度发展的影响

    Institute of Scientific and Technical Information of China (English)

    吴芳; 李利; 周代军; 李志杰

    2011-01-01

    通过测定同水胶比下拜耳法赤泥与普通硅酸盐水泥、硫铝酸盐水泥复配的水泥浆体孔溶液pH值和抗压强度,结合XRD分析研究了赤泥掺量对复配体系孔溶液碱度及抗压强度的影响.研究表明,普通硅酸盐水泥浆体和硫铝酸盐水泥浆体孔溶液碱度均随赤泥掺量的增加而增大.掺入赤泥并不会引起水泥水化后期孔溶液碱度的增加.普通硅酸盐水泥中赤泥掺量宜控制在30%以内,而硫铝酸盐水泥中赤泥掺量则不能超过20%.普通硅酸盐水泥孔溶液碱度发展与强度之间存在明显的相关性.%The pH value and compressive strengh of different bayer red-mud content with ordinary portland cement and sulphoaluminate cement paste pore solution under the same water cement ratio were tested ,The effect the red mud quantity were analyzed by XRD. Test results showed a linear increase in alkalinity of portland cement paste pore solution and sulphoaluminate cement paste pore solution with Bayer red-mud. Red mud would not increase the late alkalinity of cement-based material pore solution. the mixing amount of red mud in the portland cement should be in the range of thirty percent red mud, while the mixing amount of red mud in the sulphoaluminate cement should not exceed twenty percent. The correlation existed obvivualy between the alkalinity and strength of portland cement.

  18. Cu{sub 2}ZnSnSe{sub 4} absorbers processed from solution deposited metal salt precursors under different selenization conditions

    Energy Technology Data Exchange (ETDEWEB)

    Fella, Carolin M.; Uhl, Alexander R.; Romanyuk, Yaroslav E.; Tiwari, Ayodhya N. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Thin Films and Photovoltaics, Duebendorf (Switzerland)

    2012-06-15

    Cu{sub 2}ZnSnSe{sub 4} (CZTSe) thin film solar cells are fabricated by a simple, non-vacuum deposition of metal salts dissolved in non-hazardous solvents followed by selenization in Se atmosphere. Despite a residual carbon-rich layer between the back contact and the CZTSe absorber layer, solar cells with up to 4.28% conversion efficiency are obtained for Cu-poor and Zn-rich CZTSe absorbers. A frequently reported problem, the loss of tin, is investigated with respect to the influence of the selenization conditions such as substrate temperature and selenium partial pressure. EDX point measurements directly confirm that the remaining decomposed layer consists of a mixture of binary ZnSe and Cu{sub 2-x}Se phases if the substrate temperature is too high and not sufficient Se is supplied. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Investigation into reproducibility of a synthesis of modified zirconium phosphate (PZ) samples based on zirconium (4) salts of various quality

    Energy Technology Data Exchange (ETDEWEB)

    Benderskaya, L.A.; Bojchinova, E.S.; Nikolaeva, R.B.; Vinter, I.K. (Leningradskij Tekhnologicheskij Inst. (USSR))

    1982-03-01

    The possibility is studied of producing a PZ ionite with good ion exchange properties, reproducible from one synthesis to another, regardless of the quality of zirconium initial salt. It is established that, during the PZ synthesis on the base of Zr salts of different quality, the TPZ ionites, prepared on the base of Zr (4) soluble complex with EDTA, possess the best sorption properties at the maximum structure reproducibility. Comparatively low and definite degree of zirconium (4) polymerization in the alkaline solution of its complex with EDTA results in the formation of TPZ initial nuclei of reproducible sizes and composition, whereas their slow growth due to a gradual destruction of zirconium (4) complexonate, especially stable in an acid medium, contributes to the formation of reproducible large-globular hydrogel structure in the process of its precipitation.

  20. Molecular biology of cyanobacterial salt acclimation.

    Science.gov (United States)

    Hagemann, Martin

    2011-01-01

    High and changing salt concentrations represent major abiotic factors limiting the growth of microorganisms. During their long evolution, cyanobacteria have adapted to aquatic habitats with various salt concentrations. High salt concentrations in the medium challenge the cell with reduced water availability and high contents of inorganic ions. The basic mechanism of salt acclimation involves the active extrusion of toxic inorganic ions and the accumulation of compatible solutes, including sucrose, trehalose, glucosylglycerol, and glycine betaine. The kinetics of these physiological processes has been exceptionally well studied in the model Synechocystis 6803, leading to the definition of five subsequent phases in reaching a new salt acclimation steady state. Recent '-omics' technologies using the advanced model Synechocystis 6803 have revealed a comprehensive picture of the dynamic process of salt acclimation involving the differential expression of hundreds of genes. However, the mechanisms involved in sensing specific salt stress signals are not well resolved. In the future, analysis of cyanobacterial salt acclimation will be directed toward defining the functions of the many unknown proteins upregulated in salt-stressed cells, identifying specific salt-sensing mechanisms, using salt-resistant strains of cyanobacteria for the production of bioenergy, and applying cyanobacterial stress genes to improve the salt tolerance of sensitive organisms.

  1. Mixed salt crystallisation fouling

    CERN Document Server

    Helalizadeh, A

    2002-01-01

    The main purpose of this investigation was to study the mechanisms of mixed salt crystallisation fouling on heat transfer surfaces during convective heat transfer and sub-cooled flow boiling conditions. To-date no investigations on the effects of operating parameters on the deposition of mixtures of calcium sulphate and calcium carbonate, which are the most common constituents of scales formed on heat transfer surfaces, have been reported. As part of this research project, a substantial number of experiments were performed to determine the mechanisms controlling deposition. Fluid velocity, heat flux, surface and bulk temperatures, concentration of the solution, ionic strength, pressure and heat transfer surface material were varied systematically. After clarification of the effect of these parameters on the deposition process, the results of these experiments were used to develop a mechanistic model for prediction of fouling resistances, caused by crystallisation of mixed salts, under convective heat transfer...

  2. Salt ingestion caves.

    Directory of Open Access Journals (Sweden)

    Lundquist Charles A.

    2006-01-01

    Full Text Available Large vertebrate herbivores, when they find a salt-bearing layer of rock, say in a cliff face, can produce sizable voids where, overgenerations, they have removed and consumed salty rock. The cavities formed by this natural animal process constitute a uniqueclass of caves that can be called salt ingestion caves. Several examples of such caves are described in various publications. Anexample in Mississippi U.S.A., Rock House Cave, was visited by the authors in 2000. It seems to have been formed by deer orbison. Perhaps the most spectacular example is Kitum Cave in Kenya. This cave has been excavated to a length over 100 metersby elephants. An ancient example is La Cueva del Milodon in Chile, which is reported to have been excavated by the now extinctmilodon, a giant ground sloth. Still other possible examples can be cited. This class of caves deserves a careful definition. First, thecavity in rock should meet the size and other conventions of the locally accepted definition of a cave. Of course this requirement differsin detail from country to country, particularly in the matter of size. The intent is to respect the local conventions. The characteristicthat human entry is possible is judged to be a crucial property of any recognized cave definition. Second, the cavity should besignificantly the result of vertebrate animal consumption of salt-bearing rock. The defining process is that rock removed to form thecave is carried away in the digestive track of an animal. While sodium salts are expected to be the norm, other salts for which thereis animal hunger are acceptable. Also some other speleogenesis process, such as solution, should not be excluded as long as it issecondary in formation of a cave in question.

  3. Will salt repositories be dry?

    Science.gov (United States)

    Bredehoeft, John D.

    The National Academy of Science committee that considered geologic disposal of nuclear waste in the mid-1950s recommended salt as a repository medium, partly because of its high thermal conductivity and because it was believed to be “dry” (perhaps the appropriate thought is “impermeable”). Certainly, the fact that Paleozoic salt deposits exist in many parts of t h e world is evidence for very low rates of dissolution by moving groundwater. The fact that the dissolution rates were so small led many scientists to the conclusion that the salt beds were nearly impermeable. The major source of brine within the salt beds was thought to be fluid inclusions within salt crystals, which could migrate through differential solution toward a source of high heat. The idea that salt was uniformly “dry” was revised when exploratory drilling in the vicinity of the Waste Isolation Pilot Plant (WIPP) in New Mexico encountered brines within the Castile Formation, an evaporite deposit below the Salado Formation. The brine reservoirs were thought to be isolated pockets of brine in an otherwise “impermeable” salt section.

  4. Alkaline Waterflooding Demonstration Project, Ranger Zone, Long Beach Unit, Wilmington Field, California. Fourth annual report, June 1979-May 1980. Volume 3. Appendices II-XVII

    Energy Technology Data Exchange (ETDEWEB)

    Carmichael, J.D.

    1981-03-01

    Volume 3 contains Appendices II through XVII: mixing instructions for sodium orthosilicate; oil displacement studies using THUMS C-331 crude oil and extracted reservoir core material from well B-110; clay mineral analysis of B-827-A cores; sieve analysis of 4 Fo sand samples from B-110-IA and 4 Fo sand samples from B-827-A; core record; delayed secondary caustic consumption tests; long-term alkaline consumption in reservoir sands; demulsification study for THUMS Long Beach Company, Island White; operating plans and instructions for DOE injection demonstration project, alkaline injection; caustic pilot-produced water test graphs; well test irregularities (6/1/79-5/31/80); alkaline flood pump changes (6/1/79-5/31/80); monthly DOE pilot chemical waterflood injection reports (preflush injection, alkaline-salt injection, and alkaline injection without salt); and caustic safety procedures-alkaline chemicals.

  5. Emprego do sal di-sódico de edta como padrão no preparo de soluções Use of EDTA disodium salt as standard for preparation of solutions

    Directory of Open Access Journals (Sweden)

    Paulo H. Pereira da Silva

    2007-06-01

    Full Text Available The hydrated sodium salt of EDTA, Na2H2Y·2H2O, cannot be used as a primary standard for titrations due to uncertainties in the water content. An alkalimetric titration of the homogenized solid in the presence of a small excess of BaCl2·2H2O allows one to titrate quantitatively the released two hydrogen cations with end-point indication by phenolphthalein or potentiometry. This leads one to calculate the average molar mass of the reagent and its water content, allowing to use it to prepare EDTA standard solutions. One titrated sample led to the formula Na2H2Y·1.876 H2O, and 370.01 g.mol-1 for the average molar mass.

  6. Reduced Solubility of Polymer-Oriented Water for Sodium Salts, Sugars, Amino Acids, and other Solutes Normally Maintained at Low Levels in Living Cells,

    Science.gov (United States)

    1983-01-01

    polymer was prepared often with aid of gentle heating. The polymer solution was then inserted into 1/4 inch dialysis tubing, the ends of the sac tied...it was moved to another tube filled also with non-labelled solution and the process repeated many times until after the final washing, the sacs were...tragacanth (74C-0207); and gum xantham (888-0200); corn starch (6813-0216); potato starch (65B-2060); pectin (107B-0090); alginic acid (766-818); also

  7. Enhanced water-solubility and antibacterial activity of novel chitosan derivatives modified with quaternary phosphonium salt.

    Science.gov (United States)

    Zhu, Dan; Cheng, Honghao; Li, Jianna; Zhang, Wenwen; Shen, Yuanyuan; Chen, Shaojun; Ge, Zaochuan; Chen, Shiguo

    2016-04-01

    Chitosan (CS) has been widely recognized as an important biomaterial due to its good antimicrobial activity, biocompatibility and biodegradability. However, CS is insoluble in water in neutral and alkaline aqueous solution due to the linear aggregation of chain molecules and the formation of crystallinity. This is one of the key factors that limit its practical applications. Therefore, improving the solubility of CS in neutral and alkaline aqueous solution is a primary research direction for biomedical applications. In this paper, a reactive antibacterial compound (4-(2,5-Dioxo-pyrrolidin-1-yloxycarbonyl)-benzyl)-triphenyl-phosphonium bromide (NHS-QPS) was synthesized for chemical modification of CS, and a series of novel polymeric antimicrobial agents, N-quaternary phosphonium chitosan derivatives (N-QPCSxy, x=1-2,y=1-4) were obtained. The water solubilities and antibacterial activities of N-QPCSxy against Escherichia coli and Staphylococcus aureus were evaluated compare to CS. The water solubility of N-QPCSxy was all better than that of CS at neutral pH aqueous solution, particularly, N-QPCS14 can be soluble in water over the pH range of 3 to 12. The antibacterial activities of CS derivatives were improved by introducing quaternary phosphonium salt, and antibacterial activity of N-QPCSxy increases with degree of substitution. Overall, N-QPCS14 represents a novel antibacterial polymer material with good antibacterial activity, waters solubility and low cytotoxicity.

  8. COUPLING THE ALKALINE-SURFACTANT-POLYMER TECHNOLOGY AND THE GELATION TECHNOLOGY TO MAXIMIZE OIL PRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm Pitts; Jie Qi; Dan Wilson

    2004-10-01

    Gelation technologies have been developed to provide more efficient vertical sweep efficiencies for flooding naturally fractured oil reservoirs or more efficient areal sweep efficiency for those with high permeability contrast ''thief zones''. The field proven alkaline-surfactant-polymer technology economically recovers 15% to 25% OOIP more oil than waterflooding from swept pore space of an oil reservoir. However, alkaline-surfactant-polymer technology is not amenable to naturally fractured reservoirs or those with thief zones because much of injected solution bypasses target pore space containing oil. This work investigates whether combining these two technologies could broaden applicability of alkaline-surfactant-polymer flooding into these reservoirs. A prior fluid-fluid report discussed interaction of different gel chemical compositions and alkaline-surfactant-polymer solutions. Gel solutions under dynamic conditions of linear corefloods showed similar stability to alkaline-surfactant-polymer solutions as in the fluid-fluid analyses. Aluminum-polyacrylamide, flowing gels are not stable to alkaline-surfactant-polymer solutions of either pH 10.5 or 12.9. Chromium acetate-polyacrylamide flowing and rigid flowing gels are stable to subsequent alkaline-surfactant-polymer solution injection. Rigid flowing chromium acetate-polyacrylamide gels maintained permeability reduction better than flowing chromium acetate-polyacrylamide gels. Silicate-polyacrylamide gels are not stable with subsequent injection of either a pH 10.5 or a 12.9 alkaline-surfactant-polymer solution. Neither aluminum citrate-polyacrylamide nor silicate-polyacrylamide gel systems produced significant incremental oil in linear corefloods. Both flowing and rigid flowing chromium acetate-polyacrylamide gels produced incremental oil with the rigid flowing gel producing the greatest amount. Higher oil recovery could have been due to higher differential pressures across cores. None of

  9. Estimation of Zn mobility and biological availability in sod-podzolic soil and leached chernozem based on results of soil extraction by various salt solutions and Zn accumulation in barley plants

    Science.gov (United States)

    Pivovarova, Y. A.

    2012-04-01

    Extraction of soils by chemical reagents is widely used as a basis for forecasting the stock of the metal in the soil available to the plants. There are some doubts about how heavy metals uptake from specific soil to certain plant species can be adequately modeled on the results of chemical extraction. Problems of regulation of heavy metals in natural objects and risk assessment of soil contamination must be solved as issues of unification and standardization of existing assessment methods and new methods developing for their use in studies of the mobility of metals in soils and their availability to plants. Zn is a priority pollutant of the soil. The availability of Zn compounds to plants in two soils of different genesis was compared on the basis of their extraction by neutral salt solutions Ca(NO3)2, MgCl2, and CH3COONH4 and a pot experiment. It was shown that not only the concentration of contaminant in the extractant, but also the proportion of extractable Zn in its total content in the soil increased with increasing contamination of soil. The difference between the estimates of exchangeable Zn obtained by these methods was ~2.5 times for soddy-podzolic soil and 3-6 times for leached chernozem. The relationship between the accumulation of Zn in 14-day-old barley seedlings and the content of its exchangeable form in the soil was near linear, but the parameters of regression equations for two soils differed significantly. Chemical extraction allowed the differentiation of the mobile Zn fraction, but its accumulation by plants from different soils could not be predicted from the extractability of the element by neutral salt solutions without consideration for other soil properties.

  10. 盐穴储气库双井造腔技术现状及难点分析%Comprehensive Analysis about Dual Well Solution Mining Technology in Salt Cavern Storages

    Institute of Scientific and Technical Information of China (English)

    周俊驰; 黄孟云; 班凡生; 郑东波

    2016-01-01

    At present, solution mining in salt cavern mainly adopts the technology of the single well dissolved cavity in our country, but this general technology cannot completely meet the need of salt cavern storage construction in China, especially in the aspects of cavity size, construction cycle, ect.Another technology called dual well opera-tion in solution mining is an effective measure to solve this problem with the advantages of increasing water injection capacity, energy saving, enlarging cavity volume and shortening the period of dissolution.Based on the comprehen-sive analysis of dual well application abroad, this paper points out that dual well technology should address the as-pects of the cavity form design and control, cavity configuration monitoring and process parameters optimization in domestic fields.%目前我国在盐层建库主要采用单井溶腔技术,但常用的单井溶腔技术无论在造腔体积、建库周期等方面均已不能满足我国盐穴储气库建设日益增加的需求,而盐穴储气库双井溶腔技术具有增大注水排量、降低能耗、增大腔体体积、缩短建库周期等优点,因此在综合分析国外盐穴储气库双井溶腔技术及难点的基础上,指出腔体形态设计与控制、腔体形态监测与工艺参数优化等是国内盐穴储气库双井溶腔技术存在的主要问题,并提出了相应的解决措施。

  11. Sepiolite functionalized with N-[3-(trimethoxysilylpropyl]-ethylenediamine triacetic acid trisodium salt. Part II: Sorption of Ni2+ from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Lazarević Slavica S.

    2016-01-01

    Full Text Available sorption of Ni2+ on the sepiolite functionalized by covalent grafting of N-[3-(trimethoxysilylpropyl]ethylenediamine triacetic acid trisodium salt, MSEAS, was studied in batch experiments as a function of the initial metal concentration, the equilibration time, pH value, and temperature. The modification of sepiolite resulted in an enhanced Ni2+ retention with a capacity of 0.261 mmol/g at 298 K. The retention of Ni2+ ions occurred dominantly by specific sorption and exchange of Mg2+ ions from the sepiolite structure. The sorption process followed pseudo-second-order kinetics. The sorption equilibrium results were best described by the non-linear form of the Langmuir Sorption Equation. The values of the thermodynamic parameters (enthalpy, free energy and entropy were calculated from temperature dependent sorption isotherms and these values showed that the sorption of Ni2+ onto modified sepiolite was endothermic. [Projekat Ministarstva nauke Republike Srbije, br. III 45019 i FP7 NANOTECH FTM No. 245916

  12. Conformation Switching in Gas-Phase Complexes of Histidine with Alkaline Earth Ions

    NARCIS (Netherlands)

    Dunbar, R. C.; Hopkinson, A. C.; Oomens, J.; Siu, C. K.; Siu, K. W. M.; Steill, J. D.; Verkerk, U. H.; Zhao, J. F.

    2009-01-01

    Infrared multiple photon dissociation spectroscopy of gas-phase doubly charged alkaline earth complexes of histidine reveals a transition from dominance of the zwitterion (salt bridge, SB) conformation with Ba2+ to substantial presence of the canonical (charge-solvated, CS) conformation with Ca2+. T

  13. Hydration of beryllium(II) in aqueous solutions of common inorganic salts. A combined vibrational spectroscopic and ab initio molecular orbital study.

    Science.gov (United States)

    Rudolph, Wolfram W; Fischer, Dieter; Irmer, Gert; Pye, Cory C

    2009-09-01

    Raman spectra of aqueous beryllium perchlorate, chloride, nitrate, and sulfate solutions have been measured over a broad concentration (0.098-4.950 mol L(-1)) range. The Raman spectroscopic data suggest that the tetra-aqua beryllium(II) ion is thermodynamically stable in perchlorate, chloride, and nitrate solutions over the concentration range measured. No inner-sphere complexes in these solutions could be detected spectroscopically except in very concentrated beryllium nitrate solutions. Beryllium sulfate solutions however, show a different picture, namely the existence of a thermodynamically stable beryllium sulfato complex most likely monodentate even at very low concentrations. At very high beryllium sulfate concentrations, a small quantity of a bidentate sulfato complex was found. With a temperature increase, the sulfato complex formation increases and this demonstrates the entropically driven sulfato complex formation. Furthermore, with increased temperature the hydrolysis increases, measured by the formation of hydrogen sulfate. Ab initio geometry optimizations and frequency calculations are reported for beryllium-water clusters with only inner sphere waters, clusters with an inner sphere and an incomplete second hydration, and clusters with a higher number of waters in the second hydration sphere. The cluster, [Be(OH2)(12)(2+)] (Be[4 + 8]) with 4 water molecules in the first sphere and 8 water molecules in the second sphere gave sufficiently realistic frequencies for BeO4 skeleton in comparison to the experimental ones. However, the cluster, [Be(OH2)(18)(2+)] (Be[6 + 12]) with 6 water molecules in the inner sphere and 12 water molecules in the outer sphere on an energy minimum gave unrealistically low BeO4 frequencies. This fact demonstrates that a six-fold coordination of Be2+ can be ruled out.

  14. Salt splitting with ceramic membranes

    Energy Technology Data Exchange (ETDEWEB)

    Kurath, D. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-10-01

    The purpose of this task is to develop ceramic membrane technologies for salt splitting of radioactively contaminated sodium salt solutions. This technology has the potential to reduce the low-level waste (LLW) disposal volume, the pH and sodium hydroxide content for subsequent processing steps, the sodium content of interstitial liquid in high-level waste (HLW) sludges, and provide sodium hydroxide free of aluminum for recycle within processing plants at the DOE complex. Potential deployment sites include Hanford, Savannah River, and Idaho National Engineering Laboratory (INEL). The technical approach consists of electrochemical separation of sodium ions from the salt solution using sodium (Na) Super Ion Conductors (NaSICON). As the name implies, sodium ions are transported rapidly through these ceramic crystals even at room temperatures.

  15. Use of Different Barium Salts to Inhibit the Thaumasite Form of Sulfate Attack in Cement-based Materials

    Institute of Scientific and Technical Information of China (English)

    SU Ying; WEI Xiaochao; HUANG Jian; WANG Yingbin; HE Xingyang; WANG Xiongjue; MA Baoguo

    2016-01-01

    We investigated the effects of different barium compounds on the thaumasite form of sulphate attack (TSA) resistance of cement-based materials when they were used as admixtures in mortars. Moreover, we analyzed the inhibition mechanisms within different types of barium salts, namely BaCO3 and Ba(OH)2, on the thaumasite formation. The control cement mortar and mortars with barium salts to cement and limestone weight ratios of 0.5%, 1.0%, and 1.5% were immersed in 5% (by weight) MgSO4 solution at 5℃ to mimic TSA. Appearance, mass, and compressive strength of the mortar samples were monitored and measured to assess the general degradation extent of these samples. The products of sulphate attack were further analyzed by XRD, FTIR, and SEM, respectively. Experimental results show that different degradation extent is evident in all mortars cured in MgSO4 solution. However, barium salts can greatly inhibit such degradation. Barium in hydroxide form has better effectiveness in protection against TSA than carbonate form, which may be due to their solubility difference in alkaline cement pore solution, and the presence of these barium compounds can reduce the degree of TSA by comparison with the almost completely decomposed control samples.

  16. Changes in the Vascular Cylinder of Wild Soybean Roots Under Alkaline Stress

    Institute of Scientific and Technical Information of China (English)

    NIU Lu; LU Jing-mei; WU Dong-mei; LI Yan; GAO Ting-ting

    2014-01-01

    Changes in the vascular cylinder of wild soybean (Glycine soja Sieb. et Zucc) roots under alkaline stress were investigated in an experiment that applied 90 mmol L-1 alkaline stress for 10 d at the ifve-trifoliate plant growth stage in Huinan County, Jilin Province, China. Root samples were collected and parafifn-cut sections were made, and the root structure was observed under an optical microscope. There were signiifcant changes in the vascular cylinder of G. soja roots under alkaline stress. Root diameter was reduced and the vascular cylinder changed from tetrarch to triarch pattern. Alkaline stress resulted in reduced, diameters of root vessels, and a large amount of residual, alkaline solution was stained cyaneous in vessels. The paratracheal parenchymatous cells of the vessels were large and there was little secondary xylem. Thus, alkaline stress caused structural changes in the vascular cylinder of G. soja.

  17. Temperature-dependent solubility transition of Na₂SO₄ in water and the effect of NaCl therein: solution structures and salt water dynamics.

    Science.gov (United States)

    Bharmoria, Pankaj; Gehlot, Praveen Singh; Gupta, Hariom; Kumar, Arvind

    2014-11-06

    Dual, aqueous solubility behavior of Na2SO4 as a function of temperatures is still a natural enigma lying unresolved in the literature. The solubility of Na2SO4 increases up to 32.38 °C and decreases slightly thereafter at higher temperatures. We have thrown light on this phenomenon by analyzing the Na2SO4-water clusters (growth and stability) detected from temperature-dependent dynamic light scattering experiments, solution compressibility changes derived from the density and speed of sound measurements, and water structural changes/Na2SO4 (ion pair)-water interactions observed from the FT-IR and 2D DOSY (1)H NMR spectroscopic investigations. It has been observed that Na2SO4-water clusters grow with an increase in Na2SO4 concentration (until the solubility transition temperature) and then start decreasing afterward. An unusual decrease in cluster size and solution compressibility has been observed with the rise in temperature for the Na2SO4 saturated solutions below the solubility transition temperature, whereas an inverse pattern is followed thereafter. DOSY experiments have indicated different types of water cluster species in saturated solutions at different temperatures with varying self-diffusion coefficients. The effect of NaCl (5-15 wt %) on the solubility behavior of Na2SO4 at different temperatures has also been examined. The studies are important from both fundamental and industrial application points of view, for example, toward the clean separation of NaCl and Na2SO4 from the effluent streams of textile and tannery industries.

  18. The Upside to Hg-DOM Associations for Water Quality: Removal of Hg from Solution Using Coagulaion with Metal-Based Salts

    Science.gov (United States)

    Henneberry, Y.; Kraus, T. E.; Fleck, J.; Krabbenhoft, D. P.; Horwath, W. R.

    2011-12-01

    This study assessed the potential use of metal-based coagulants to remove dissolved mercury (Hg) from natural waters and provides information regarding the importance of Hg associations with the dissolved organic matter (DOM) fraction and metal hydroxides. Previous research indicated coagulants were not effective at removing Hg from solution; however those studies used high concentrations of Hg, which did not reflect naturally occurring concentrations of Hg. Filtered water collected from an agricultural drain in the Sacramento-San Joaquin Delta (Delta) was treated with three industrial-grade coagulants (ferric chloride, ferric sulfate, and polyaluminum chloride) to determine their efficacy in removing both inroganic (IHg) and methylmercury (MeHg) from the water column. The Delta suffers from elevated surface water Hg concentrations and as a result is listed as an imparied water body. Coagulants removed up to 85% of DOM from solution. In the absence of DOM, all three coagulants released IHg into solution, however in the presence of DOM the coagulants removed up to 97% of IHg and 80% of MeHg. Results suggest that the removal of Hg is mediated by DOM-coagulant interactions. There was a preferential association of IHg with the more aromatic, higher molecular weight fraction of DOM but no such relationship was found for MeHg. This study offers new fundamental insights regarding large-scale removal of Hg at environmentally relevant concentrations. Research using isotopically labeled Hg is providing insight into whether coagulation can remove recently added Hg (e.g. atmospheric deposition) from solution and whether once formed, the floc can remove additional Hg from the water column.

  19. Impact of pulsed electric field on electrodialysis process performance and membrane fouling during consecutive demineralization of a model salt solution containing a high magnesium/calcium ratio.

    Science.gov (United States)

    Cifuentes-Araya, Nicolás; Pourcelly, Gérald; Bazinet, Laurent

    2011-09-01

    Pulsed electric fields (PEFs), hashed modes of current consisting in the application of a constant current density during a fixed time (Ton) followed by a pause lapse (Toff), were recently demonstrated as an effective alternative for mineral fouling mitigation and process intensification during electrodialysis (ED) treatments. Recent ED studies have continuously reported a considerable mineral fouling formation on ion-exchange membranes, especially during the demineralization of solutions containing a high Mg/Ca ratio and a basified concentrate solution. The aim of this study was to evaluate the process performance under two different PEF conditions on a mineral solution containing a mineral mixture giving a high Mg(2+)/Ca(2+) ratio of 2/5. Two different pause-lapse durations (PEF ratio 1 (Ton/Toff 10s/10s); PEF ratio 0.3 (Ton/Toff 10s/33.3 s)) during consecutive ED treatments and their comparison with dc current were evaluated at a current density of 40 mA/cm(2). Our results showed that PEFs resulted in an intensification of ED process, enhancing the demineralization rates (DRs), reducing the system resistance (SR), and reducing the fouling and energy consumption (EC). PEF ratio 1 was the most optimal condition among the current regimes applied, leading to faster and higher demineralization rates due to a lower fouling and with low energy consumption during all consecutive runs.

  20. Immobilization of cesium in alkaline activated fly ash matrix

    Science.gov (United States)

    Fernandez-Jimenez, A.; Macphee, D. E.; Lachowski, E. E.; Palomo, A.

    2005-11-01

    The immobilization potential of alkaline activated fly ash (AAFA) matrices for cesium has been investigated. The presence of Cs in the AAFA pastes, prepared using 8M NaOH solution as activator, showed no significant adverse effects on mechanical strength or microstructure, nor were significant quantities of Cs leached following application of the Toxic Characteristic Leaching Procedure (TCLP) and American Nuclear Society (ANS) 16.1 leaching protocols. Microstructural analysis shows Cs associated with the main reaction product in the AAFA suggesting that cesium is chemically bound rather than physically encapsulated. It is proposed that cesium is incorporated into the alkaline aluminosilicate gel, a precursor for zeolite formation.

  1. Alkaline protease production by solid state fermentation on polyurethane foam

    OpenAIRE

    Hongzhang, Chen; Hui, Wang; Aijun, Zhang; Zuohu, Li

    2006-01-01

    This paper investigated the process of solid state fermentation (SSF) using PUF (polyurethane foam) as inert solid support to produce alkaline protease. Maximal enzyme activity was 2185U/ml at pH 9.0, incubation temperature 32 0C inoculum amount of 1.0 % (v/v) , nutrient solution3.75 ml/g PUF, incubation time for 2 h and 15.0 mM of added CaCl2. Under the same conditions, the yield of alkaline protease produced by SSF using PUF as support is higher than that by submerged fermentation (SMF).

  2. Salt Dependence of the Radius of Gyration and Flexibility of Single-stranded DNA in Solution probed by Small-angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Adelene Y.L.; Lipfert, Jan; Herschlag, Daniel; Doniach, Sebastian

    2012-07-06

    Short single-stranded nucleic acids are ubiquitous in biological processes and understanding their physical properties provides insights to nucleic acid folding and dynamics. We used small angle x-ray scattering to study 8-100 residue homopolymeric single-stranded DNAs in solution, without external forces or labeling probes. Poly-T's structural ensemble changes with increasing ionic strength in a manner consistent with a polyelectrolyte persistence length theory that accounts for molecular flexibility. For any number of residues, poly-A is consistently more elongated than poly-T, likely due to the tendency of A residues to form stronger base-stacking interactions than T residues.

  3. Spectral features of guanidinium-carboxylate salt bridges. The combined ATR-IR and theoretical studies of aqueous solution of guanidinium acetate

    Science.gov (United States)

    Levina, Elena O.; Lokshin, Boris V.; Mai, Bich D.; Vener, Mikhail V.

    2016-08-01

    The spectrum of guanidinium acetate in aqueous solution has been recorded by attenuated total reflectance infrared spectroscopy (ATR-IR). Assignments of the bands have been done using the polarizable continuum model (PCM). Three IR intensive bands at 1670, 1550, and 1410 cm-1 are associated with stretching and bending vibrations of the groups forming a ring of six heavy atoms of the bidentate configuration of guanidinium acetate. The relatively weak broad band near 2200 cm-1 is tentatively assigned to the stretching vibration of the Nsbnd H⋯O fragment of the hydrogen-bonded ion pairs.

  4. Further Studies, About New Elements Production, by Electrolysis of Cathodic Pd Thin–Long Wires, in Alcohol-Water Solutions (H, D) and Th-Hg Salts. New Procedures to Produce Pd Nano-Structures

    CERN Document Server

    Celani, F; Righi, E; Trenta, G; Catena, C; D’Agostaro, G; Quercia, P; Andreassi, V; Marini, P; Di Stefano, V; Nakamura, M; Mancini, A; Sona, P G; Fontana, F; Gamberale, L; Garbelli, D; Celia, E; Falcioni, F; Marchesini, M; Novaro, E; Mastromatteo, U

    2005-01-01

    Abstract They were continued, at National Institute of Nuclear Physics, Frascati National Laboratories-Italy, the systematic studies about detection of new elements, some even with isotopic composition different from natural one, after prolonged electrolysis of Pd wires. The electrolytic solution adopted is the, unusual, used from our experimental group since 1999. In short, it was a mixture of both heavy ethyl alcohol (C2H5OD at 90-95%) and water (D2O, at 10-5%), with Th salts at micromolar concentration and Hg at even lower concentration (both of spectroscopic purity). The liquid solutions, before use, were carefully vacuum distilled (and on line 100nm filtered) at low temperatures (30-40°C) and analysed by ICP-MS. The pH was kept quite mild (acidic at about 3-4). The cathode is Pd (99.9% purity) in the shape of long (60cm) and thin wires (diameter only 0.05mm). Before use, it is carefully cleaned and oxidised by Joule heating in air following a (complex) procedure from us continuously improved (since 1995...

  5. POLYETHER POLYURETHANE FROM MODIFIED WHEAT STRAW OXYGEN-ALKALINE LIGNIN

    Institute of Scientific and Technical Information of China (English)

    QuanxiaoLiu; HuaiyuZhan; BeihaiHe; ShuhuiYang; JianhuaLiu; JianluLiu(1); ZhenxingPang

    2004-01-01

    Polyether polyurethane was synthesized from modified wheat straw oxygen-alkaline lignin, polyethylene glycol and two different diisocyanates (diphenylemethane-4, 4'-diisocyanate, tolulene diisocyanate) by solution casting method, its properties were investigated. The results show that modified wheat straw oxygen-alkaline lignin can substitute part of polyethylene glycol to react with diisocyanate to synthesize polyurethane. The molar ratio of NCO to OH and modified wheat straw oxygen-alkaline lignin content affect the properties of lignin-based polyether polyurethane respectively. The addition of plasticizer in the polyurethane synthesis process improves the properties of synthesized polyurethane, especially the elasticity of polyurethane. The synthesized polyurethane from modified wheat straw oxygen-alkali lignin can be used as both engineering plastic and hard foam plastic in future.

  6. POLYETHER POLYURETHANE FROM MODIFIED WHEAT STRAW OXYGEN-ALKALINE LIGNIN

    Institute of Scientific and Technical Information of China (English)

    Quanxiao Liu; Huaiyu Zhan; Beihai He; Shuhui Yang; Jianhua Liu; Jianlu Liu; Zhenxing Pang

    2004-01-01

    Polyether polyurethane was synthesized from modified wheat straw oxygen-alkaline lignin,polyethylene glycol and two different diisocyanates (diphenylemethane-4, 4′-diisocyanate, tolulene diisocyanate) by solution casting method, its properties were investigated. The results show that modified wheat straw oxygen-alkaline lignin can substitute part of polyethylene glycol to react with diisocyanate to synthesize polyurethane. The molar ratio of NCO to OH and modified wheat straw oxygen-alkaline lignin content affect the properties of lignin-based polyether polyurethane respectively. The addition of plasticizer in the polyurethane synthesis process improves the properties of synthesized polyurethane, especially the elasticity of polyurethane. The synthesized polyurethane from modified wheat straw oxygen-alkali lignin can be used as both engineering plastic and hard foam plastic in future.

  7. 腌制温度和食盐用量对咸鸭蛋蛋黄脂质的影响%Effect of pickling temperature and concentration of salt solution on lipid of duck egg yolk

    Institute of Scientific and Technical Information of China (English)

    龙门; 宋野; 杜庆飞; 周頔; 蔡华珍; 詹歌

    2015-01-01

    为进一步提高咸鸭蛋品质,以鸭蛋为原料,分析不同腌制条件对蛋黄中脂质存在形式、脂质氧化速率的影响。结果表明,在腌制过程中,随着腌制温度的升高、腌制时间的延长,蛋黄指数、脂质含量、蛋黄皂化值均显著增加(P<0.05);腌制用盐量对蛋黄中脂质的皂化值有显著的促进作用(P<0.05)。在腌制液食盐质量分数为20%~30%时,升高腌制温度对蛋黄中脂质二次氧化(硫代巴比妥酸值thiobarbituric acid, TBARS)有显著促进作用(P<0.05),在腌制30 d后,TBARS无显著变化;并且在试验条件下,提高腌制用盐量能显著提高蛋黄中的 TBARS(P<0.05);动力学分析表明,增加食盐用量能够降低蛋黄中脂质初始氧化反应的活化能,从而促进脂质氧化。因此,通过调整腌制用盐量及腌制温度能够实现对咸鸭蛋蛋黄中脂质氧化的调控,由此得出咸鸭蛋较好的腌制条件为腌制温度25℃、腌制用盐量25 g/(100 g)、腌制时间为25 d,该研究结果可以为咸鸭蛋的腌制生产提供技术参考。%Salted duck egg is a kind of Chinese-style pickled egg with a long shelf life. Its pleasant and fragrant taste is preferred by most of the people in China and other Southeast Asian countries. Salted duck egg is normally made by pickling the duck eggs in 20.0%-30.0% NaCl solution at room temperature (30℃) for 30 days. Lipid is one of the important structural and functional compositions for duck eggs; it has a very important impact on the quality of the duck egg, and has close relationship with the nutrition value and flavor and texture of duck eggs. The lipid oxidation also plays a role in the human body health, and is closely related to many diseases of the human body. The prooxidant effect of NaCl will enhance the oxidation of duck egg lipid during pickling. In that case, the objective of this paper was to research the oxygenolysis of the lipid

  8. HIGH YIELD AND RAPID SYNTHESES METHODS FOR PRODUCING METALLO-ORGANIC SALTS

    DEFF Research Database (Denmark)

    2005-01-01

    A new method for preparing salts of metal cations and organic acids, especially divalent salts of alkaline earth metal ions from group II of the periodic system and carboxylic acids. The method comprising the use of a high temperature (about 90° or more) and, optionally. high pressure, in order t...... to obtain a higher yield, purity and faster reaction speed than obtained with known synthesis methods. In particular, the present invention relates to the production of strontium salts of carboxylic acids. Novel strontium salts are also provided by the present method.......A new method for preparing salts of metal cations and organic acids, especially divalent salts of alkaline earth metal ions from group II of the periodic system and carboxylic acids. The method comprising the use of a high temperature (about 90° or more) and, optionally. high pressure, in order...

  9. Salt effects on the air/solution interfacial properties of PEO-containing copolymers: equilibrium, adsorption kinetics and surface rheological behavior.

    Science.gov (United States)

    Llamas, Sara; Mendoza, Alma J; Guzmán, Eduardo; Ortega, Francisco; Rubio, Ramón G

    2013-06-15

    Lithium cations are known to form complexes with the oxygen atoms of poly(oxyethylene) chains. The effect of Li(+) on the surface properties of three block-copolymers containing poly(oxyethylene) (PEO) have been studied. Two types of copolymers have been studied, a water soluble one of the pluronic family, PEO-b-PPO-b-PEO, PPO being poly(propyleneoxyde), and two water insoluble ones: PEO-b-PS and PEO-b-PS-b-PEO, PS being polystyrene. In the case of the pluronic the adsorption kinetics, the equilibrium surface tension isotherm and the aqueous/air surface rheology have been measured, while for the two insoluble copolymers only the surface pressure and the surface rheology have been studied. In all the cases two different Li(+) concentrations have been used. As in the absence of lithium ions, the adsorption kinetics of pluronic solutions shows two processes, and becomes faster as [Li(+)] increases. The kinetics is not diffusion controlled. For a given pluronic concentration the equilibrium surface pressure increases with [Li(+)], and the isotherms show two surface phase transitions, though less marked than for [Li(+)]=0. A similar behavior was found for the equilibrium isotherms of PEO-b-PS and PEO-b-PS-b-PEO. The surface elasticity of these two copolymers was found to increase with [Li(+)] over the whole surface concentration and frequency ranges studied. A smaller effect was found in the case of the pluronic solutions. The results of the pluronic solutions were modeled using a recent theory that takes into account that the molecules can be adsorbed at the surface in two different states. The theory gives a good fit for the adsorption kinetics and a reasonably good prediction of the equilibrium isotherms for low and intermediate concentrations of pluronic. However, the theory is not able to reproduce the isotherm for [Li(+)]=0. Only a semi-quantitative prediction of the surface elasticity is obtained for [pluronic]≤1×10(-3) mM.

  10. Sulphate removal from sodium sulphate-rich brine and recovery of barium as a barium salt mixture.

    Science.gov (United States)

    Vadapalli, Viswanath R K; Zvimba, John N; Mulopo, Jean; Motaung, Solly

    2013-01-01

    Sulphate removal from sodium sulphate-rich brine using barium hydroxide and recovery of the barium salts has been investigated. The sodium sulphate-rich brine treated with different dosages of barium hydroxide to precipitate barium sulphate showed sulphate removal from 13.5 g/L to less than 400 mg/L over 60 min using a barium to sulphate molar ratio of 1.1. The thermal conversion of precipitated barium sulphate to barium sulphide achieved a conversion yield of 85% using coal as both a reducing agent and an energy source. The recovery of a pure mixture of barium salts from barium sulphide, which involved dissolution of barium sulphide and reaction with ammonium hydroxide resulted in recovery of a mixture of barium carbonate (62%) and barium hydroxide (38%), which is a critical input raw material for barium salts based acid mine drainage (AMD) desalination technologies. Under alkaline conditions of this barium salt mixture recovery process, ammonia gas is given off, while hydrogen sulfide is retained in solution as bisulfide species, and this provides basis for ammonium hydroxide separation and recovery for reuse, with hydrogen sulfide also recoverable for further industrial applications such as sulfur production by subsequent stripping.

  11. Scanning electron microscopic and X-ray micro analysis on tooth enamel exposed to alkaline agents.

    Science.gov (United States)

    Taubee, Fabian; Steiniger, Frank; Nietzsche, Sandor; Norén, Jörgen G

    2010-01-01

    The background of this study comprises two clinical cases, where patients exposed to aerosols of an alkaline and surface active cleaning agent developed loss of enamel substance on their teeth, further resulting in loss of teeth and partially destroyed soft tissues. The alkaline cleaning agent consisted of potassium hydroxide and various surfactants. The purpose of this study was to investigate possible changes in morphology and composition in human teeth enamel exposed to alkaline solutions, by means of X-ray micro analysis (XRMA), FTIR-spectroscopic analyses and scanning electron microscopy (SEM). Extracted premolars, exposed to potassium hydroxide solutions and alkaline cleaning solution,were analyzed by means of XRMA and SEM. Enamel powder, exposed to cleaning solution, was analyzed by means of FTIR. The SEM analysis revealed an increased porosity of the enamel surface and partially loss of enamel substance after exposure to alkaline solutions. The XRMA analyses revealed a decrease in carbon concentration while phosphorous and calcium showed no marked changes. The FTIR analyses showed no significant changes in peak heights or peak positions for phosphate, carbonate or hydroxide. It was concluded that human teeth enamel exposed to alkaline solutions showed loss of organic substance, marked pores in enamel surface and loss of substance in the enamel surface.

  12. TMC-1 Mediates Alkaline Sensation in C. elegans through Nociceptive Neurons.

    Science.gov (United States)

    Wang, Xiang; Li, Guang; Liu, Jie; Liu, Jianfeng; Xu, X Z Shawn

    2016-07-06

    Noxious pH triggers pungent taste and nocifensive behavior. While the mechanisms underlying acidic pH sensation have been extensively characterized, little is known about how animals sense alkaline pH in the environment. TMC genes encode a family of evolutionarily conserved membrane proteins whose functions are largely unknown. Here, we characterize C. elegans TMC-1, which was suggested to form a Na(+)-sensitive channel mediating salt chemosensation. Interestingly, we find that TMC-1 is required for worms to avoid noxious alkaline environment. Alkaline pH evokes an inward current in nociceptive neurons, which is primarily mediated by TMC-1 and to a lesser extent by the TRP channel OSM-9. However, unlike OSM-9, which is sensitive to both acidic and alkaline pH, TMC-1 is only required for alkali-activated current, revealing a specificity for alkaline sensation. Ectopic expression of TMC-1 confers alkaline sensitivity to alkali-insensitive cells. Our results identify an unexpected role for TMCs in alkaline sensation and nociception.

  13. 2nd Generation Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Yde, Lars; Kjartansdóttir, Cecilia Kristin; Allebrod, Frank;

    This report provides the results of the 2nd Generation Alkaline Electrolysis project which was initiated in 2008. The project has been conducted from 2009-2012 by a consortium comprising Århus University Business and Social Science – Centre for Energy Technologies (CET (former HIRC)), Technical...

  14. Cyanoplatinate (II) salts as luminescent materials for scintillation counting

    DEFF Research Database (Denmark)

    Bergsøe, P.; Hansen, P.Gregers; Jacobsen, C.F.

    1962-01-01

    described, and for two other salts information on the composition was lacking. Many of the salts are colorless and the luminescence is in most cases in the blue region. The measurements include light yield and decay time under excitation with fast electrons. Most of the salts were found to be efficient......Eleven cyanoplatinate (II) salts have been studied under excitation with fast, charged particles. The salts were prepared via the barium compound, and crystals were grown from aqueous solutions. The formulae were determined by standard analytical procedures. Four of the salts were not previously...

  15. Alkaline resistant ceramics; Alkalimotstaandskraftiga keramer

    Energy Technology Data Exchange (ETDEWEB)

    Westberg, Stig-Bjoern [Vattenfall Utveckling AB, Aelvkarleby (Sweden)

    2001-02-01

    Despite durability in several environments, ceramics and refractories can not endure alkaline environments at high temperature. An example of such an environment is when burning biofuel in modern heat and power plants in which the demand for increasing efficiency results in higher combustion temperatures and content of alkaline substances in the flue gas. Some experiences of these environments has been gained from such vastly different equipment as regenerator chambers in the glass industry and MHD-generators. The grains of a ceramic material are usually bonded together by a glassy phase which despite it frequently being a minor constituent render the materials properties and limits its use at elevated temperature. The damage is usually caused by alkaline containing low-melting phases and the decrease of the viscosity of the bonding glass phase which is caused by the alkaline. The surfaces which are exposed to the flue gas in a modern power plant are not only exposed to the high temperature but also a corroding and eroding, particle containing, gas flow of high velocity. The use of conventional refractory products is limited to 1300-1350 deg C. Higher strength and fracture toughness as well as durability against gases, slag and melts at temperatures exceeding 1700 deg C are expected of the materials of the future. Continuous transport of corrosive compounds to the surface and corrosion products from the surface as well as a suitable environment for the corrosion to occur in are prerequisites for extensive corrosion to come about. The highest corrosion rate is therefore found in a temperature interval between the dew point and the melting point of the alkaline-constituent containing compound. It is therefore important that the corrosion resistance is sufficient in the environment in which alkaline containing melts or slag may appear. In environments such as these, even under normal circumstances durable ceramics, such as alumina and silicon carbide, are attacked

  16. Coupling the Alkaline-Surfactant-Polymer Technology and The Gelation Technology to Maximize Oil Production

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm Pitts; Jie Qi; Dan Wilson; Phil Dowling; David Stewart; Bill Jones

    2005-12-01

    Gelation technologies have been developed to provide more efficient vertical sweep efficiencies for flooding naturally fractured oil reservoirs or reservoirs with different sand lenses with high permeability contrast. The field proven alkaline-surfactant-polymer technology economically recovers 15% to 25% OOIP more crude oil than waterflooding from swept pore space of an oil reservoir. However, alkaline-surfactant-polymer technology is not amenable to naturally fractured reservoirs or reservoirs with high permeability contrast zones because much of injected solution bypasses target pore space containing oil. This work investigates whether combining these two technologies could broaden applicability of alkaline-surfactant-polymer flooding into these reservoirs. Fluid-fluid interaction with different gel chemical compositions and alkaline-surfactant-polymer solution with pH values ranging from 9.2 to 12.9 have been tested. Aluminum-polyacrylamide gels are not stable to alkaline-surfactant-polymer solutions at any pH. Chromium-polyacrylamide gels with polymer to chromium ion ratios of 25 or greater were stable to alkaline-surfactant-polymer solutions if solution pH was 10.6 or less. When the polymer to chromium ion was 15 or less, chromium-polyacrylamide gels were stable to alkaline-surfactant-polymer solutions with pH values up to 12.9. Chromium-xanthan gum gels were stable to alkaline-surfactant-polymer solutions with pH values of 12.9 at the polymer to chromium ion ratios tested. Silicate-polyacrylamide, resorcinol-formaldehyde, and sulfomethylated resorcinol-formaldehyde gels were also stable to alkaline-surfactant-polymer solutions with pH values ranging from 9.2 to 12.9. Iron-polyacrylamide gels were immediately destroyed when contacted with any of the alkaline-surfactant-polymer solutions with pH values ranging from 9.2 to 12.9. Gel solutions under dynamic conditions of linear corefloods showed similar stability to alkaline-surfactant-polymer solutions as in

  17. Dependence of DNA persistence length on ionic strength of solutions with monovalent and divalent salts: a joint theory-experiment study

    CERN Document Server

    Brunet, Annaël; Salomé, Laurence; Rousseau, Philippe; Destainville, Nicolas; Manghi, Manoel

    2015-01-01

    Using high-throughput Tethered Particle Motion single molecule experiments, the double-stranded DNA persistence length, $L_p$, is measured in solutions with Na$^+$ and Mg$^{2+}$ ions of various ionic strengths, $I$. Several theoretical equations for $L_p(I)$ are fitted to the experimental data, but no decisive theory is found which fits all the $L_p$ values for the two ion valencies. Properly extracted from the particle trajectory using simulations, $L_p$ varies from 30~nm to 55~nm, and is compared to previous experimental results. For the Na$^+$ only case, $L_p$ is an increasing concave function of $I^{-1}$, well fitted by Manning's electrostatic stretching approach, but not by classical Odjik-Skolnick-Fixman theories with or without counter-ion condensation. With added Mg$^{2+}$ ions, $L_p$ shows a marked decrease at low $I$, interpreted as an ion-ion correlation effect, with an almost linear law in $I^{-1}$, fitted by a proposed variational approach.

  18. 氧化镁铵盐法制备高纯过氧化镁%Preparation of High Purity Magnesium Peroxide by Magnesia and Ammonium Salt Solutions

    Institute of Scientific and Technical Information of China (English)

    朱海丽;