Journal articles: 'Temperatura bivalente'

1

Costa Câmara, Ana Paula. "PROPRIEDADES FÍSICO – MECÂNICAS E AMBIENTAL DE CERÂMICA ESTRUTURAL COM ESTABILIZAÇÃO DO ÍON MANGANÊS." HOLOS 5 (October 29, 2012): 142. http://dx.doi.org/10.15628/holos.2012.1107.

Full text

Abstract:

Neste trabalho estudou-se a adição do íon manganês bivalente a uma massa argilosa do estado do Rio Grande do Norte a fim de avaliar a viabilidade tecnológica e ambiental do material cerâmico. A matéria-prima cerâmica foi caracterizada por análise química (FRX) e difratometria de raios – X (DRX). O íon metálico foi adicionado na forma de soluções aquosas nas concentrações de 100, 150 e 200 mg/L. Os corpos de prova obtidos por extrusão e sinterizados nas temperaturas de 850, 950 e 1050 °C foram avaliados por ensaios cerâmicos e ambiental de solubilidade. As propriedades tecnológicas avaliadas foram: retração linear de queima, absorção de água, porosidade aparente, massa específica aparente e tensão de ruptura à flexão em três pontos. Propriedades como porosidade aparente e absorção de água não apresentaram variações significativas em função da concentração do íon manganês. Por outro lado, a tensão de ruptura à flexão cresce com o aumento da temperatura independente da concentração do íon. Os resultados indicaram que a cerâmica com o íon manganês incorporado e estabilizado, é adequada para a fabricação de diversos produtos cerâmicos, tais como tijolo maciço e revestimento semi-poroso, sem oferecer risco ao meio ambiente.

APA, Harvard, Vancouver, ISO, and other styles

2

Singare, Pravin U., Akmal L. Khan Mohammed, and N. N. Dixit. "Study on Preferential Selectivity of Nuclear Grade Resin Indion-223 towards some Bivalent Ions." International Letters of Chemistry, Physics and Astronomy 34 (May 2014): 11–21. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.34.11.

Full text

Abstract:

In the present paper attempts are made to understand the selectivity of nuclear grade cation exchange resin Indion-223 in H+ form towards Ca2+ and Mg2+ bivalent ions in the solution based on thermodynamic concept. It was observed that with rise in temperature the equilibrium constant K values for H+/Ca2+ uni-bivalet ion exchange reactions increases from 0.000397 to 0.000639. Similarly for H+/Mg2+ uni-bivalet ion exchange reactions the equilibrium constant K values increases from 0.000177 to 0.000333. The increase in equilibrium constant values with rise in temperature indicate endothermic ion exchange reactions having the enthalpy change values of 38.92 and 51.46 kJ/ mol respectively. The difference in K values and enthalpy values were used to predict the selectivity behaviour of the resin towards the Ca2+ and Mg2+ bivalent ions in the solution. The thermodynamic concept of the present study can be applied to understand the selectivity behaviour of different nuclear as well as non-nuclear grade resins towards wide range of ionic species present in the exchanging liquid medium.

APA, Harvard, Vancouver, ISO, and other styles

3

Singare, Pravin U., Akmal L. Khan Mohammed, and N. N. Dixit. "Comparative Study of Uni-Univalent H⁺/Na⁺ and Uni-Bivalent H⁺/Ca²⁺ Ion Exchange Reactions Using Nuclear Grade Resin Indion-223." International Letters of Chemistry, Physics and Astronomy 33 (May 2014): 127–35. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.33.127.

Full text

Abstract:

The present paper deals with the ion exchange equilibrium studies of uni-univalent and uni-bivalent ion exchange reactions using nuclear grade anion exchange resin Indion-223 in H+ form towards Na+ and Ca2+ ions in the solution. It was observed that with rise in temperature the equilibrium constants K values for H+/Na+ uni-univalet ion exchange reaction increases from 0.01389 to 0.01855. Similarly for H+/Ca2+ uni-bivalet ion exchange reaction the equilibrium constants K values increases from 0.000397 to 0.000639. The increase in equilibrium constant values with rise in temperature indicate endothermic ion exchange reactions having the enthalpy change values of 25.55 and 38.92 kJ/ mol respectively.

APA, Harvard, Vancouver, ISO, and other styles

4

Singare, Pravin U., Akmal L. Khan Mohammed, and N. N. Dixit. "Thermodynamics of Uni-Univalent H⁺/K⁺ and Uni-Bivalent H⁺/Ca²⁺ Ion Exchange Reactions Using Nuclear Grade Resin Indion-223." International Letters of Chemistry, Physics and Astronomy 33 (May 2014): 190–98. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.33.190.

Full text

Abstract:

The present paper deals with the thermodynamic of uni-univalent and uni-bivalent ion exchange reactions using nuclear grade anion exchange resin Indion-223. It was observed that with rise in temperature the equilibrium constants K values for H+/K+ uni-univalet ion exchange reaction increases from 0.01710 to 0.02374. Similarly for H+/Ca2+ uni-bivalet ion exchange reaction the equilibrium constants K values increases from 0.000397 to 0.000639. The increase in K values with rise in temperature for both the reactions indicates its endothermic nature having the enthalpy change values of 22.72 and 38.92 kJ/ mol respectively. The technique used here can be extended further to standardise the process parameters in order to bring about the efficient separation of the desired ionic species from the solution

APA, Harvard, Vancouver, ISO, and other styles

5

Singare, Pravin U., Akmal L. Khan Mohammed, and N. N. Dixit. "Ion Exchange Equilibrium Studies of Uni-Univalent H⁺/Na⁺ and Uni-Bivalent H⁺/Mg²⁺ Ion Exchange Reactions Using Nuclear Grade Resin Indion-223." International Letters of Chemistry, Physics and Astronomy 33 (May 2014): 199–207. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.33.199.

Full text

Abstract:

In the present investigation the uni-univalent and uni-bivalent ion exchange reactions were studied using nuclear grade anion exchange resin Indion-223 in H+ form. It was observed that for H+/Na+ uni-univalet ion exchange reaction, with rise in temperature the equilibrium constants K values increases from 0.01389 to 0.01855. Similarly increase in K values was observed from 0.000177 to 0.000333 for H+/Mg2+ uni-bivalet ion exchange reaction. The increase in equilibrium constant values with rise in temperature indicate endothermic ion exchange reactions having the enthalpy change values of 25.55 and 51.46 kJ/ mol respectively. It is expected that the present study will provide valuable information in order to decide about the selection of those resins for efficient separation of various ionic species present in the industrial waste water effluents.

APA, Harvard, Vancouver, ISO, and other styles

6

Singare, Pravin U., Akmal L. Khan Mohammed, and N. N. Dixit. "Study of Uni-Univalent H⁺/K⁺ and Uni-Bivalent H⁺/Mg²⁺ Ion Exchange Reactions Using Nuclear Grade Resin Indion-223." International Letters of Chemistry, Physics and Astronomy 33 (May 2014): 231–39. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.33.231.

Full text

Abstract:

In the present paper the uni-univalent and uni-bivalent ion exchange reactions were investigated using nuclear grade anion exchange resin Indion-223 in H+ form. For both H+/K+ uni-univalet ion exchange reactions and H+/Mg2+ uni-bivalet ion exchange reactions, the equilibrium constant K values increases from 0.01710 to 0.02374 and from 0.000177 to 0.000333 respectively as the reaction temperature rises from 35.0 °C to 45.0 °C. The increase in K values with temperature suggest endothermic ion exchange reactions having the enthalpy change values of 22.72 and 51.46 kJ/ mol respectively. The results of such studies will help in selection of suitable ion exchange resins in order to bring about efficient separation of different ionic species present in the waste water effluents released from nuclear as well as chemical process industries.

APA, Harvard, Vancouver, ISO, and other styles

7

Kopyto, Renata, Charles F. Crane, and David A. Sleper. "Effect of temperature on meiosis and fertility in Festuca mairei × Festuca arundinacea var. glaucescens." Genome 32, no. 4 (August 1, 1989): 708–18. http://dx.doi.org/10.1139/g89-501.

Full text

Abstract:

This study considered the effects of three continuous growth temperatures (14, 21, and 28 °C) on apparent genomic structure, apparent chromosome arm ratio, pollen abortion, and meiotic nonreduction in full-sib genotypes of Festuca mairei × F. arundinacea var. glaucescens. Ten genotypes were sampled for meiosis and 20 for pollen. The metaphase I (MI) data for each sampled combination of genotype, temperature, and replication were subjected to a bootstrap algorithm that calculated 95% confidence limits for each class of meiotic figure and for the ratio of ring bivalents to total bivalents, the total number of chromosomes in multivalents per cell, and the mean arm-binding frequency. These confidence limits permitted an evaluation of the significance of differences among genotypes, temperatures, and replications. The MI data were also subjected to two types of numerical models to investigate apparent genomic structure and mean effective chromosome arm ratio, i.e., pairing regulation and extent of chiasma interference across the centromere. The hybrids overall exhibited a 2:2 (AABB) genomic structure, but there were significant differences among genotypes in arm-binding frequency and frequencies of univalents, rod bivalents, and ring bivalents. Except for desynapsis and impaired chromosome contraction in one genotype at 28 °C, temperature had little effect; optimized genomic structure was slightly more 2:1:1 (like AABC) at 14 °C and chiasma interference increased slightly at 28 °C. One genotype was monosomic but meiotically normal. Pollen stainability was significantly depressed at 14 °C, while microspore micronuclei were more numerous. Pollen diameter was least at 21 °C regardless of degree of abortion.Key words: meiosis, meiotic modeling, temperature, pollen fertility, Festuca.

APA, Harvard, Vancouver, ISO, and other styles

8

Doseva, Nadezhda, and Daniela Chakyrova. "Life cycle cost analysis of different residential heat pump systems." E3S Web of Conferences 207 (2020): 01014. http://dx.doi.org/10.1051/e3sconf/202020701014.

Full text

Abstract:

Nowadays, the application of air-source heat pumps for heating and cooling in residential buildings has been increased significantly. The main occasion for this is the accessibility of a heat source for these devices - the external air. Nevertheless, the increase of the energy efficiency of the air source heat pump systems is a difficult design problem because their capacity and performance are a function of the dynamically changing parameters of the outdoor air. Because of that, the main aim of this study is to develop an approach for choosing a structural scheme of an air-to-water heat pump system under specific climatic conditions. The considered systems are monovalent, bivalent-parallel and bivalent-alternative heat pump systems. In the current paper is conducted a dynamic energy modeling of heating and cooling demand of a typical residential building situated in Varna, Bulgaria and applying the bin temperature data. It is assessed the effect of the heat pump capacity over the annual and seasonal energy performance of the heat pump systems. It is established the effect of the bivalent temperature, cut-off temperature and on-off cycles duration on rates of the criteria for techno-economic assessment. The seasonal coefficient of performance (SCOP), seasonal energy efficiency rate (SEER) and life cycle costs (LCC) of the analyzed heat pump systems are adopted as assessment parameters.

APA, Harvard, Vancouver, ISO, and other styles

9

Demchenko, A., Y. Chang, E. Chikoidze, B. Berini, C. Lefèvre, F. Roulland, C. Ulhaq-Bouillet, et al. "Tuning the conductivity type in a room temperature magnetic oxide: Ni-doped Ga0.6Fe1.4O3 thin films." RSC Advances 6, no. 34 (2016): 28248–56. http://dx.doi.org/10.1039/c6ra01540a.

Full text

Abstract:

The mechanism responsible for conduction in pulsed laser deposited thin films of room temperature ferrimagnetic Ga_0.6Fe_1.4O₃ is fully elucidated. The conduction type can be tuned from n to p through doping with bivalent Ni ions.

APA, Harvard, Vancouver, ISO, and other styles

10

Shan, Yue Jin, Yoko Kanai, Keitaro Tezuka, and Hideo Imoto. "Synthesis and Electromagnetic Properties of Ca₂MTeO₆ (M = Mn, Co, Mg)." Advances in Science and Technology 45 (October 2006): 2572–75. http://dx.doi.org/10.4028/www.scientific.net/ast.45.2572.

Full text

Abstract:

Ordered perovskite-type oxides, Ca2MTeO6 (M = Mn, Co, Mg), were synthesized by a solid-state reaction method. All of samples belonged to space group P21/n and were insulators at room temperature. However, their electronic conductivities tended large gradually with a rise of temperature. Ca2MnTeO6 and Ca2CoTeO6 showed anti-ferromagnetism, and their Neel temperatures were 10 K and 7 K, respectively. The effective magnetic moment of manganese ion was 5.8 μB while its valence was bivalence in Ca2MnTeO6.

APA, Harvard, Vancouver, ISO, and other styles

11

Long, Li Juan, Wen Tao He, Min Min Zhang, Kai Zhang, Min He, Shu Hao Qin, and Jie Yu. "Preparation, Characterization of Substituted Aromatic Heterocyclic Phosphate Salts and the Application in Isotactic Polypropylene." Advanced Materials Research 652-654 (January 2013): 463–69. http://dx.doi.org/10.4028/www.scientific.net/amr.652-654.463.

Full text

Abstract:

Substituted aromatic heterocyclic phosphate salts were synthesized by a new method and characterized by fourier transform infrared spectroscopy(FT-IR) and thermogravimetry (TG) method. The characteristic absorption bands ascribed to the stretching vibration of P=O group and P-O group verify the successful synthesis of substituted aromatic heterocyclic phosphate salts. When compared with sodium salt, the thermal stability of other salts declines. Their nucleation effects on isotactic polypropylene(iPP) were investigated with differential scanning calorimeter(DSC) and influences on mechanical, optical properties of iPP were also studied. The DSC result shows that with 0.15wt% nucleating agents incorporated into iPP, monovalent salts have a good performance, bivalent salts have less nucleation effect on the crystallization temperature. But the mass fraction of crystallinity of iPP with manganese salt could be increased by 5.2% even it has a weak ability relatively on crystallization temperature. And the mechanical and optical properties of iPP with manganese salt almost reach to iPP containing lithium salt. The results demonstrate that bivalent manganses salt is a kind of new effective nucleating agent when designing compound nucleating agents.

APA, Harvard, Vancouver, ISO, and other styles

12

Lokhande, R. S., and S. A. Parab. "Study of temperature effect on uni-univalent and uni-bivalent ion exchange reaction." Russian Journal of Physical Chemistry A 83, no. 5 (January 2009): 771–74. http://dx.doi.org/10.1134/s0036024409050161.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Khabzina, Y., C. Laroche, C. Pagis, and D. Farrusseng. "Monovalent and bivalent cations exchange isotherms for faujasites X and Y." Physical Chemistry Chemical Physics 19, no. 26 (2017): 17242–49. http://dx.doi.org/10.1039/c7cp02051a.

Full text

Abstract:

This study addresses the modeling of exchange isotherms for faujasite-type zeolites X and Y with K⁺, Cs⁺, Ca²⁺ and Ba²⁺ cations based on a large experimental dataset obtained under operating conditions of 0.5 N total normality and an exchange temperature of 80 °C.

APA, Harvard, Vancouver, ISO, and other styles

14

Woo, Jung Hee, Yuan Yi Liu, Scott Stavrou, and David M. Neville. "Increasing Secretion of a Bivalent Anti-T-Cell Immunotoxin by Pichia pastoris." Applied and Environmental Microbiology 70, no. 6 (June 2004): 3370–76. http://dx.doi.org/10.1128/aem.70.6.3370-3376.2004.

Full text

Abstract:

ABSTRACT The bivalent anti-T-cell immunotoxin A-dmDT390-bisFv(G4S) was developed for treatment of T-cell leukemia and autoimmune diseases and for tolerance induction for transplantation. This immunotoxin was produced extracellularly in toxin-sensitive Pichia pastoris JW102 (Mut+ ) under control of the AOX1 promoter. There were two major barriers to efficient immunotoxin production, the toxicity of the immunotoxin for P. pastoris and the limited capacity of P. pastoris to secrete the immunotoxin. The immunotoxin toxicity resulted in a decrease in the methanol consumption rate, cessation of cell growth, and low immunotoxin productivity after the first 22 h of methanol induction. Continuous cell growth and continuous immunotoxin secretion after the first 22 h of methanol induction were obtained by adding glycerol to the methanol feed by using a 4:1 methanol-glycerol mixed feed as an energy source and by continuously adding a yeast extract solution during methanol induction. The secretory capacity was increased from 22.5 to 37 mg/liter by lowering the induction temperature. A low temperature reduced the methanol consumption rate and protease activity in the supernatant but not cell growth. The effects of adding glycerol and yeast extract to the methanol feed were synergistic. Adding yeast extract primarily enhanced methanol utilization and cell growth, while adding glycerol primarily enhanced immunotoxin production. The synergy was further enhanced by decreasing the induction temperature from 23 to 15Ã¯Â¿Â½C, which resulted in a robust process with a yield of 37 mg/liter, which was sevenfold greater than the yield previously reported for a toxin-resistant CHO cell expression system. This methodology should be applicable to other toxin-related recombinant proteins in toxin-sensitive P. pastoris.

APA, Harvard, Vancouver, ISO, and other styles

15

Yang, Wen Qiang, Juan An, Xiao Li Yuan, and Wen Tang Xia. "Manganese Removal from Electrolytic Manganese Residue Using Ozone." Advanced Materials Research 997 (August 2014): 754–57. http://dx.doi.org/10.4028/www.scientific.net/amr.997.754.

Full text

Abstract:

This paper deals with experimental investigations related to removal of manganese (II) from electrolytic manganese residues by using ozone as oxidant. Ozone was used in this study to oxidize manganese converting bivalent manganese to high valence states, the oxidized salts will precipitate as manganese oxides, that to reach the concentration of the pollutant under its limit values in water. Effects of reaction temperature, reaction contact time and initial pH value on the manganese (II) removal were investigated. The results indicated that the removal rate exceeded 99.9 percent, and the manganese (II) in solution was lower than 0.1 mg·L-1 under the conditions of reaction temperature 45 °C, reaction contact time 40 min and initial pH 12.

APA, Harvard, Vancouver, ISO, and other styles

16

Cheng, Yalin, Kaiqian Wang, Biyang Tu, Yang Xia, Jiaqian Zhang, Shan Xue, and Haisheng Tao. "High‐Temperature Reduction of Calcium Alginate to Carbon Sphere for Efficient Removal of Bivalent Cadmium." ChemistrySelect 4, no. 31 (August 16, 2019): 9058–64. http://dx.doi.org/10.1002/slct.201902329.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Khenkin, L. V., Alla A. Novakova, Nikolai S. Perov, and A. A. Vompe. "Magnetic Properties Variations in Iron Complexes with Benzimidazole Derivatives Depending on the System Spin State." Solid State Phenomena 190 (June 2012): 633–36. http://dx.doi.org/10.4028/www.scientific.net/ssp.190.633.

Full text

Abstract:

Complexes of bivalent and trivalent iron with ligands based on benzimidazole derivatives have been synthesized and investigated. Chloride-ion was used as anion. Samples ligands differed from each other in the length of alkyl radical. Some samples were found in a mix-valence state, that complicated spin transition observation. Combination of Mossbauer spectroscopy and magnetic moment in high field (15kOe) measurements in the temperatures range 130K - 350K allowed us to establish the valence of iron ions under spin transition in our samples and spin transition temperature frameworks for these mix-valence compounds.

APA, Harvard, Vancouver, ISO, and other styles

18

Ardelean, I., I. Barbur, V. Timar, and Gh Borodi. "Structural, Electrical and Magnetic Properties of Pb2Mg1-xCoxWO6 Solid Solutions." Modern Physics Letters B 17, no. 20n21 (September 10, 2003): 1135–41. http://dx.doi.org/10.1142/s021798490300613x.

Full text

Abstract:

X-ray diffraction, electrical and magnetic measurements performed on Pb 2 Mg 1-x Co x WO 6 solid solutions with 0≤x≤1 are reported. By cobalt substitution for magnesium the diffraction patterns indicate the transition from orthorhombic structure characteristics for Pb 2 MgWO 6 to the cubic structure specific for Pb 2 CoWO 6. The Curie temperature decreases with cobalt content from 38°C to 32°C. The magnetic data indicate that the cobalt ions are in a bivalent state and, for x>0.1, experience negative magnetic interactions.

APA, Harvard, Vancouver, ISO, and other styles

19

Jayashree, S., Jeyavathana Samuel, and R. Vashantha. "Sorption of Bivalent Ions by Cymbopogon citratus: Characterisation and Investigation of Biosorptive Capacity and Mechanism." Journal of Environmental Science and Pollution Research 4, no. 3 (August 20, 2018): 297–302. http://dx.doi.org/10.30799/jespr.140.18040303.

Full text

Abstract:

The main objective of this study was to investigate the removal of cadmium(II) ions from aqueous solution using raw Cymbopogon citratus as an adsorbent. It was characterized by FT-IR, XRD, SEM-EDAX and its physical parameters were analyzed. Different factors such as pH, contact time, initial concentration and temperature were studied. Maximum adsorption was taken place at the optimum pH of 6 and the equilibrium data were analyzed by Langmuir, Freundlich and Temkin Isotherm models. Among those isotherm models Langmuir and Temkin were fitted well with good correlation coefficient (R2). The negative values of ΔG⁰ for all temperature shows the adsorption process for cadmium(II) ion was spontaneous in nature and feasible. The negative value of enthalpy change ΔH⁰ shows the adsorption process is exothermic and the positive value of ΔS⁰ indicates the disorderness or randomness process of adsorption. The positive value of Ea indicates the higher solution temperature favors the adsorption of metal ion onto RCC. The experimental data were analyzed by kinetic studies such as pseudo-first order, pseudo-second order and intra-particle diffusion models. Desorption was also studied and the recovery of the adsorbent was found to be 10%. Thus on the basis of these investigations the present study concludes that the raw Cymbopogon citratus (RCC) was found to be highly effective, nontoxic, environmental friendly and low cost adsorbent for the removal of toxic Cd(II) ions from aqueous solution.

APA, Harvard, Vancouver, ISO, and other styles

20

Wang, Xian Gang. "Effect of Substrate Temperature on Structural and Optical Properties of ZnO:Co Thin Films Fabricated by Laser Molecular Beam Epitaxy." Advanced Materials Research 834-836 (October 2013): 64–69. http://dx.doi.org/10.4028/www.scientific.net/amr.834-836.64.

Full text

Abstract:

We synthesized ZnO:Co thin films on sapphire (0001) substrates by laser molecular beam epitaxy (LMBE) method. X-ray diffraction (XRD) spectra indicated that all samples possessed wurtzite structure with the preferential c-axis-orientation and the value of the c-axis lattice decreased with increasing substrate temperature. UVvis transmittance spectra and X-ray photoelectron spectroscopy (XPS) implied that Co2+ions incorporated into ZnO lattice with substitution for Zn2+ions and the non-bivalent Zn existed in as-prepared thin films. Two emission bands located at 418 nm (2.97 eV) and 490 nm (2.53 eV) were observed from the photoluminescence (PL) spectra of all samples. The two emission bands were in relation to Zn interstitials and the complex of VOand Zni(VOZni). The quantity of the Zn interstitials remained mostly invariable as substrate temperature increased.

APA, Harvard, Vancouver, ISO, and other styles

21

Nguefack Marius Borel, Nguimezong, Josepha Foba-Tendo, Divine Mbom Yufanyi, Ekane Peter Etape, Jude Namanga Eko, and Lambi John Ngolui. "Averrhoa carambola: A Renewable Source of Oxalic Acid for the Facile and Green Synthesis of Divalent Metal (Fe, Co, Ni, Zn, and Cu) Oxalates and Oxide Nanoparticles." Journal of Applied Chemistry 2014 (September 17, 2014): 1–9. http://dx.doi.org/10.1155/2014/767695.

Full text

Abstract:

A green, simple, and environmentally benign synthetic approach has been utilised to obtain some bivalent metal oxalates from Averrhoa carambola juice extract, without any purification or special treatment of the juice. The main acid components (oxalic acid and ascorbic acid) of the juice were identified by HPLC technique. The effect of temperature on the purity of the product has been investigated. The as-synthesized metal oxalates were thermally decomposed at low temperatures to their respective metal oxide nanoparticles. The metal oxalates and their respective thermal decomposition products were characterized by Fourier Transform Infrared spectroscopy, X-ray diffraction analysis, and thermogravimetry.

APA, Harvard, Vancouver, ISO, and other styles

22

Rawat, J. P., and Archana Agrawal. "Influence of temperature on the cation exchange equilibrium of some bivalent cations on Duolite ES 467." Colloids and Surfaces A: Physicochemical and Engineering Aspects 71, no. 1 (May 1993): 73–81. http://dx.doi.org/10.1016/0927-7757(93)80029-e.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Sadida, Faozia Faleha, and Ma Manchur. "Production and Optimization of Cellulase Activity of Thermomonospora Viridis Isolated From Rice Straw." Bangladesh Journal of Botany 50, no. 2 (June 18, 2021): 395–404. http://dx.doi.org/10.3329/bjb.v50i2.54097.

Full text

Abstract:

A highly cellulolytic actinomycete SR1 was locally isolated from rice straw and provisionally identified as Thermomonospora viridis. Optimum pH, temperature, carbon and nitrogen sources for its cellulase production were 6.5, 35°C, Carboxymethyl cellulase (CMC) and yeast extract, respectively whereas those of cellulase activity were 7.5, 40°C, CMC and peptone respectively. The effects of various metal ions and different reductant and inhibitors on its cellulase activity were investigated. Univalent Ag+ was found to decrease the enzyme activity whereas increased by bivalent Mg2+. Ethylene diamine tetraacetic acid (EDTA) caused remarkable decrease of cellulase activity but β-Mercaptoethanol stimulated its cellulase activity. Bangladesh J. Bot. 50(2): 395-404, 2021 (June)

APA, Harvard, Vancouver, ISO, and other styles

24

Lodha, Rahul, Carmen Oprea, Tom Troczynski, and George Oprea. "Sintering Studies on Magnesia-Rich Chromium-Free Spinel-Bonded Basic Refractories." Advances in Science and Technology 70 (October 2010): 108–13. http://dx.doi.org/10.4028/www.scientific.net/ast.70.108.

Full text

Abstract:

Basic bricks with Cr2O3 from chrome ore, as the spinel forming oxide, are used in the non-ferrous industry because of their corrosion resistance against fayalite-type slags, rich in FeO. Our objective in this study was to replace Cr3+ with Me4+ ions, which along with Fe3+ could maintain the spinel formation capability with MgO and perform similarly against fayalite slags in non-ferrous furnaces. Our preliminary research studies showed that Cr-free spinels in the MgO-Al2O3-FeOx-Me4+O2 systems could perform against fayalite slags similar to the complex (Mg2+, Fe2+)O·(Cr3+, Fe3+, Al3+)2O3 spinel, the main corrosion resistant component in the magnesia-chrome bricks. The incorporation of iron oxide in the MgO-Al2O3-Me4+O2 systems would contribute to reactive sintering and also in decreasing the solubility of both the ferrous and ferric ions present in the fayalite slag. Phase analysis on stoichiometric mixes showed that the use of tetravalent cation oxides like tin dioxide (SnO2) and titanium dioxide (TiO2) can induce high solubility of spinel in magnesia. In order to maintain charge balance, two trivalent cations were replaced by a tetravalent and a bivalent cation causing the additional bivalent cation to occupy the octahedral position thereby creating an inversion in position of the bivalent ions similar to the behaviour exhibited by Fe3+ occupying tetrahedral site in complex spinel phase of magnesia-chrome ceramics. Most of the magnesia-chrome refractories have ~60 wt. % MgO and hence our experimental mixes contained that amount and called “magnesia-rich” compositions, to be distinguished from the stoichiometric MgAl2O4 spinel. Our findings showed that the incorporation of nano TiO2 powders reduces the temperature of spinel formation as the diffusion path is shortened and thus activates both synthesis and sintering. Compositions containing 60 wt. % magnesia with alumina, nano TiO2 and Fe2O3 fired below 1500°C for 3 hours resulted in complete spinel formation and open porosity less than 5%.

APA, Harvard, Vancouver, ISO, and other styles

25

Богданова, Валентина Владимировна, Ольга Игоревна Кобец, and Александр Васильевич Врублевский. "Dependence of the fire retardant and fire extinguishing efficiency of compositions based on phosphates of bivalent and trivalent ammonium metals on their physicochemical properties." Journal of Civil Protection 4, no. 4 (November 20, 2020): 367–77. http://dx.doi.org/10.33408/2519-237x.2020.4-4.367.

Full text

Abstract:

Purpose. The object of research were fire-retardant and fire-extinguishing agents based on ammonium phosphates of bivalent and trivalent metals used for the treatment of forest combustible materials (FCM), including wood and peat. The subject of the research was to determine the fire-retardant and fire-extinguishing effectiveness of these agents, depending on their physical and chemical properties determined by the conditions of synthesis. The aim was to establish common traits or difference in the mechanism of inhibition of combustion of FCM by metallophosphate systems of various chemical compositions, as well as to reveal the role of the processes occurring in the condensed phase under the influence of their thermal decomposition products. The main task was to study the physicochemical, thermal properties of fire-retardant and fire-extinguishing agents, as well as fire-protected samples of peat and other FCM in the temperature range on the burning surface of natural materials (200–500 °C). Methods. X-ray phase analysis, differential scanning calorimetry, chemical analysis. Findings. The factors determining the fire-retardant and fire-extinguishing efficiency of synthetic agents based on phosphates of bivalent and trivalent ammonium metals with controlled properties depending on the synthesis conditions with respect to FCM, wood and peat have been determined. A process has been established that has a dominant effect on stopping their combustion – inhibition of radical reactions in the gas phase by volatile nitrogen-containing products. At the same time, it was shown that when developing new fire-retardant and fire-extinguishing agents, it is necessary to take into account their properties such as the ability to form thermal insulating structures in the condensed phase. Application field of research. The results obtained in this work can be used to create new fire-retardant and fire-extinguishing synthetic compositions based on ammonium phosphates of bivalent and trivalent metals for the treatment of forest fuels.

APA, Harvard, Vancouver, ISO, and other styles

26

Stromer, M. H., M. A. Ritter, Y. Y. Pang, and R. M. Robson. "Effect of cations and temperature on kinetics of desmin assembly." Biochemical Journal 246, no. 1 (August 15, 1987): 75–81. http://dx.doi.org/10.1042/bj2460075.

Full text

Abstract:

Smooth-muscle desmin, which was isolated from avian gizzard, was purified and used to form reconstituted intermediate filaments. Filament assembly was done in the presence of physiological cations, Ca2+, Mg2+, Na+, and Na+ plus Mg2+, and with non-physiological cations Cu2+ and Ni2+. Assembly was done at 2 degrees, 22 degrees and 37 degrees C, and was monitored by absorbance and by electron microscopy. Absorbance increased most rapidly during the first 2-5 min and then increased at a slower rate with the physiological cations, but decreased after that time with the non-physiological cations. For each physiological cation, absorbance increased with increasing temperature. This was particularly evident with Ca2+, which produced the lowest absorbance at 2 degrees C and the highest at 37 degrees C. When ionic strength was comparable, filament-forming buffers that contained bivalent cations were associated with higher absorbance values. Filament diameters were significantly smaller 60 min after assembly initiation than after 5 min. Average filament diameters, when formed in the presence of Cu2+ or Ni2+, were 10% greater than in the presence of the physiological cations and did not show a consistent tendency to decrease as time increased. These results demonstrate the importance, not only of the pH and ionic composition of the filament-forming buffer, but also of the temperature and duration of dialysis for reconstitution of desmin filaments.

APA, Harvard, Vancouver, ISO, and other styles

27

Mackow, Natalie, Emérito Amaro-Carambot, Bo Liang, Sonja Surman, Matthias Lingemann, Lijuan Yang, Peter L. Collins, and Shirin Munir. "Attenuated Human Parainfluenza Virus Type 1 (HPIV1) Expressing the Fusion Glycoprotein of Human Respiratory Syncytial Virus (RSV) as a Bivalent HPIV1/RSV Vaccine." Journal of Virology 89, no. 20 (July 29, 2015): 10319–32. http://dx.doi.org/10.1128/jvi.01380-15.

Full text

Abstract:

ABSTRACTLive attenuated recombinant human parainfluenza virus type 1 (rHPIV1) was investigated as a vector to express the respiratory syncytial virus (RSV) fusion (F) glycoprotein, to provide a bivalent vaccine against RSV and HPIV1. The RSV F gene was engineered to include HPIV1 transcription signals and inserted individually into three gene locations in each of the two attenuated rHPIV1 backbones. Each backbone contained a single previously described attenuating mutation that was stabilized against deattenuation, specifically, a non-temperature-sensitive deletion mutation involving 6 nucleotides in the overlapping P/C open reading frames (ORFs) (CΔ170) or a temperature-sensitive missense mutation in the L ORF (LY942A). The insertion sites in the genome were pre-N (F1), N-P (F2), or P-M (F3) and were identical for both backbones.In vitro, the presence of the F insert reduced the rate of virus replication, but the final titers were the same as the final titer of wild-type (wt) HPIV1. High levels of RSV F expression in cultured cells were observed with rHPIV1-CΔ170-F1, -F2, and -F3 and rHPIV1-LY942A-F1. In hamsters, the rHPIV1-CΔ170-F1, -F2, and -F3 vectors were moderately restricted in the nasal turbinates, highly restricted in lungs, and genetically stablein vivo. Among the CΔ170vectors, the F1 virus was the most immunogenic and protective against wt RSV challenge. The rHPIV1-LY942Avectors were highly restrictedin vivoand were not detectably immunogenic or protective, indicative of overattenuation. The CΔ170-F1 construct appears to be suitably attenuated and immunogenic for further development as a bivalent intranasal pediatric vaccine.IMPORTANCEThere are no vaccines for the pediatric respiratory pathogens RSV and HPIV. We are developing live attenuated RSV and HPIV vaccines for use in virus-naive infants. Live attenuated RSV strains in particular are difficult to develop due to their poor growth and physical instability, but these obstacles could be avoided by the use of a vaccine vector. We describe the development and preclinical evaluation of live attenuated rHPIV1 vectors expressing the RSV F protein. Two different attenuated rHPIV1 backbones were each engineered to express RSV F from three different gene positions. The rHPIV1-CΔ170-F1 vector, bearing an attenuating deletion mutation (CΔ170) in the P/C gene and expressing RSV F from the pre-N position, was attenuated, stable, and immunogenic against the RSV F protein and HPIV1 in the hamster model and provided substantial protection against RSV challenge. This study provides a candidate rHPIV1-RSV-F vaccine virus suitable for continued development as a bivalent vaccine against two major childhood pathogens.

APA, Harvard, Vancouver, ISO, and other styles

28

Zhou, Junmei, Lianghong Yin, Chenbin Wu, Sijia Wu, Jidong Lu, Hailing Fang, and Yongchang Qian. "Screening of an Alkaline CMCase-Producing Strain and the Optimization of its Fermentation Condition." Current Pharmaceutical Biotechnology 21, no. 13 (November 28, 2020): 1304–15. http://dx.doi.org/10.2174/1389201021666200129123818.

Full text

Abstract:

Objective: Alkaline Carboxymethyl Cellulase (CMCase) is an attractive enzyme for the textile, laundry, pulp, and paper industries; however, commercial preparations with sufficient activity at alkaline conditions are scarce. Methods: High CMCase-producing bacterial isolate, SX9-4, was screened out from soil bacteria, which was identified as Flavobacterium sp. on the basis of 16S rDNA sequencing. Results: The optimum pH and temperature for CMCase reaction were 8.0 and 55°C, respectively. Alkaline CMCase was stable over wide pH (3.0-10.6) and temperature (25-55°C) ranges. Enzyme activity was significantly inhibited by the bivalent cations Mn2+ and Cu2+, and was activated by Fe2+. To improve the alkaline CMCase production of SX9-4, fermentation parameters were selected through onefactor- at-a-time and further carried out by response surface methodologies based on a central composite design. Conclusion: High CMCase production (57.18 U/mL) was achieved under the optimal conditions: 10.53 g/L carboxymethylcellulose sodium, 7.74 g/L glucose, 13.71 g/L peptone, and 5.27 g/L ammonium oxalate.

APA, Harvard, Vancouver, ISO, and other styles

29

Zele, Andreja. "Between grammar and dictionary: With special reference to Slovene verb." Juznoslovenski filolog, no. 69 (2013): 91–114. http://dx.doi.org/10.2298/jfi1369091z.

Full text

Abstract:

Slovene resources confirm that verbal aspect and aspectualness depend on the morphological, lexical, syntactic, and other characteristics of a particular language. Since verbal aspect is directly connected to the meaning of a particular verb, as well as its structural and semantic-syntactic abilities, it is considered to be an essential characteristic in terms of the language system of every language. The specific features of aspectualness, especially if we take into account its connectedness to a given language system, are confirmed by various contrastive studies, which also place considerable emphasis on a number of general aspectual characteristics that can be applied to all languages. Within every language system, for example, the grammatical (morphological), lexical, and syntactic aspectualness are distinguished from one another, whereas in the case of a particular text, the relationship between aspect, time, and mood cannot be overlooked. What remains central in both current and future discussions is establishing the relationship between aspectualness and temporality within a particular language or languages. Cases of ?aspectual competitiveness?, related to the temporal structure of a given sentence, have been noted in Slovene as well, especially in examples like Sem ze vecerjal - Sem ze povecerjal (?I already had dinner - I already finished my dinner?), Vedno smo k obstojecemu doprinesli tudi nekaj novega - Vedno smo k obstojecemu doprinasali tudi nekaj novega (?We always contributed something new to the existing condition - We always used to contribute something new to the existing condition?), etc. That the behavior of the imperfect may vary in the past and future is shown by examples like Temperatura se je dvigovala ?visala, padala in spet visala? (The temperature kept rising ?rising, falling, and rising again?), Temperatura se bo dvigovala ?vedno samo navzgor, brez nihanja? (The temperature will keep on rising ?it will rise without falling?). It is also important how a particular dictionary presents verbal valency as a developmental category. The most common is the change from monovalent verbs to bivalent or governed verbs. When considering the valency of non-deverbal nouns and adjectives, it must be noted that especially in the case of nondeverbal adjectives, valency is the consequence of the dynamic meaning of semantically similar verbs, which can replace non-deverbal adjectives in a particular sentence.

APA, Harvard, Vancouver, ISO, and other styles

30

San, Jingshan, Sai Wang, Jianjia Yu, Ning Liu, and Robert Lee. "Nanoparticle-Stabilized Carbon Dioxide Foam Used In Enhanced Oil Recovery: Effect of Different Ions and Temperatures." SPE Journal 22, no. 05 (February 15, 2017): 1416–23. http://dx.doi.org/10.2118/179628-pa.

Full text

Abstract:

Summary This paper reports the study of the effect of different ions (monovalent, bivalent, and multiple ions) on nanosilica-stabilized carbon dioxide (CO2) foam generation. CO2 foam was generated by coinjecting CO2/5,000 ppm nanosilica dispersion (dispersed in different concentrations of brine) into a sandstone core under 1,500 psi and at different temperatures. A sapphire observation cell was used to determine the foam texture and foam stability. Pressure drop across the core was measured to estimate the foam mobility. The results indicated that more CO2 foam was generated as the sodium chloride (NaCl) concentration increased from 1.0 to 10%. In addition, the foam bubble became smaller and foam stability improved with the increase in NaCl concentration. The CO2-foam mobility decreased from 13.1 to 2.6 md/cp when the NaCl concentration increased from 1 to 10%. For the bivalent ions, the generated CO2-foam mobility decreased from 19.7 to 4.8 md/cp when CaCl2 concentration increased from 0.1 to 1.0%. Synthetic produced water with total dissolved solids (TDS) of 18,583 ppm was prepared to investigate the effect of multiple ions on foam generation. The results showed that stable CO2 foam was generated as the synthetic produced water and nanosilica dispersion/CO2 flowed through a porous medium. The lifetime of the foam was observed to be more than 2 days as the foam stood at room temperature. Mobility of the foam was calculated as 5.2 md/cp.

APA, Harvard, Vancouver, ISO, and other styles

31

Liu, Deman, Jiang Diao, Yiyu Qiu, Guang Wang, Gang Li, and Bing Xie. "Determination of chromium valence state in the CaO–SiO2–FeO–MgO–CrOx system by X-ray photoelectron spectroscopy." High Temperature Materials and Processes 39, no. 1 (July 29, 2020): 351–56. http://dx.doi.org/10.1515/htmp-2020-0036.

Full text

Abstract:

AbstractThe chromium valence states in the CaO–SiO2–FeO–MgO–CrOx system were investigated by X-ray photoelectron spectroscopy (XPS). The results indicated that the XPS peaks of Cr 2p3/2 and Cr 2p1/2 locate at the binding energy of ∼577 and ∼586 eV, respectively. There are three kinds of chromium ions such as bivalent Cr(ii), trivalent Cr(iii), and hexavalent Cr(vi) in the CaO–SiO2–FeO–MgO–CrOx slag. Cr(iii) is the dominant valence state, and more than 77.99% Cr is trivalent Cr(iii). The fraction of Cr(ii)/Cr is in the range of 11.24–17.22%. The fraction of Cr(vi)/Cr is below 4.80%. The fraction of Cr(ii)/Cr decreases with increasing slag basicity, Cr2O3 content, temperature, or oxygen pressure log(PO2), while the fraction of Cr(iii)/Cr increases with increasing basicity, Cr2O3 content, temperature, or oxygen pressure. The trend of change is opposite. Low log(PO2), high Cr2O3 content, and high temperature are beneficial to reduce the toxic hexavalent Cr(vi). The slag basicity has little influence on the fraction of Cr(vi)/Cr.

APA, Harvard, Vancouver, ISO, and other styles

32

Yuan, Dong Qing, Ming Zhou, and Jian Ting Xu. "Element Characterization of AlZnO by Laser Induced Breakdown Spectroscopy (LIBS)." Applied Mechanics and Materials 34-35 (October 2010): 365–70. http://dx.doi.org/10.4028/www.scientific.net/amm.34-35.365.

Full text

Abstract:

We calculate the temperature of excited plasma, found that will be enhanced with pulse energy increased. The delay time and the pulse energy were very important to the LIBS signal and define the -0.5μs was very suitable to this experiment, determined the intensity of emission spectra was linear to the pulse energy when the delay time was fixed. By change the delay time, got the emission of bivalence ionization of Zn was just less than 500ns.At last, we had researched the effect of element concentration and the thickness of film on signal intensity. When the concentration of Al being increased from 2.5% to 5%, the intensity of signal enhanced double. At the same time the content of Zn being decreased from 78% to 76%, the intensity of signal had just no change.

APA, Harvard, Vancouver, ISO, and other styles

33

Liang, Sheng Kang, and Dan Dan Song. "Characteristics of a Extracellular Bioflocculant from a Serratia plumuthica Isolate." Advanced Materials Research 79-82 (August 2009): 223–26. http://dx.doi.org/10.4028/www.scientific.net/amr.79-82.223.

Full text

Abstract:

Physico-chemical and flocculating properties of a bioflocculant, producing by a Serratia plumuthica isolate, were studied. The bioflocculant was identified as an acid polysaccharide consisting of galactose, talose, glucose, mannose and galaturonic acid in a ratio of 34.5:5.1:24.5:29.6: 9.2. Its molecular weight was estimated to be 1.8×106. The bioflocculant was found to be effective for flocculation of a kaolin suspension, when added at a concentration of 1~10 mg/L, in a broad pH range of 2~9 and temperature range of 10~80°C. Its flocculating activity was synergistically stimulated by the bivalent or trivalent cations such as Ca2+, Mg2+, Al3+ and Fe3+. In addition, it could efficiently flocculate a variety of suspensions, including paper-making wastewater, oil-producing wastewater, black ink, alga cell suspension and activated sludge.

APA, Harvard, Vancouver, ISO, and other styles

34

Han, Dongmei, F. Holger Försterling, Xiaoyan Li, Jeffrey R. Deschamps, Hui Cao, and James M. Cook. "Determination of the stable conformation of GABAA-benzodiazepine receptor bivalent ligands by low temperature NMR and X-ray analysis." Bioorganic & Medicinal Chemistry Letters 14, no. 6 (March 2004): 1465–69. http://dx.doi.org/10.1016/j.bmcl.2004.01.018.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Sharma, Sangita, Dipika Dalwadi, and Madhurjya Neog. "A study of the formation constants of ternary and quaternary complexes of some bivalent transition metals." Journal of the Serbian Chemical Society 75, no. 1 (2010): 75–82. http://dx.doi.org/10.2298/jsc1001075s.

Full text

Abstract:

The formation of hetero-ligand 1:1:1, M(II)-Opda-Sal/Gly ternary and 1:1:1:1, M(II)-Opda-Sal-Gly quaternary complexes, where M(II) = Ni, Cu, Zn and Cd; Opda = o-phenylenediamine, Sal = salicylic acid, Gly = glycine, was studied pH-metrically in aqueous medium. The formation constants for the resulting ternary and quaternary complexes were evaluated at a constant ionic strength, ? = 0.20 mol dm-3 and temperature, 30?0.1 ?C. The order of the formation constants in terms of the metal ion for both type of complexes was found to be Cu(II) > Ni(II) > Zn(II) > Cd(II). This order was explained based on the increasing number of fused rings, the coordination number of the metal ions, the Irving - William order and the stability of various species. The expected species formed in solution were pruned with the Fortran IV program SPEPLOT and the stability of the ternary and quaternary complexes is explained.

APA, Harvard, Vancouver, ISO, and other styles

36

McNally, Karen, Evan Berg, Daniel B. Cortes, Veronica Hernandez, Paul E. Mains, and Francis J. McNally. "Katanin maintains meiotic metaphase chromosome alignment and spindle structure in vivo and has multiple effects on microtubules in vitro." Molecular Biology of the Cell 25, no. 7 (April 2014): 1037–49. http://dx.doi.org/10.1091/mbc.e13-12-0764.

Full text

Abstract:

Assembly of Caenorhabditis elegans female meiotic spindles requires both MEI-1 and MEI-2 subunits of the microtubule-severing ATPase katanin. Strong loss-of-function mutants assemble apolar intersecting microtubule arrays, whereas weaker mutants assemble bipolar meiotic spindles that are longer than wild type. To determine whether katanin is also required for spindle maintenance, we monitored metaphase I spindles after a fast-acting mei-1(ts) mutant was shifted to a nonpermissive temperature. Within 4 min of temperature shift, bivalents moved off the metaphase plate, and microtubule bundles within the spindle lengthened and developed a high degree of curvature. Spindles eventually lost bipolar structure. Immunofluorescence of embryos fixed at increasing temperature indicated that MEI-1 was lost from spindle microtubules before loss of ASPM-1, indicating that MEI-1 and ASPM-1 act independently at spindle poles. We quantified the microtubule-severing activity of purified MEI-1/MEI-2 complexes corresponding to six different point mutations and found a linear relationship between microtubule disassembly rate and meiotic spindle length. Previous work showed that katanin is required for severing at points where two microtubules intersect in vivo. We show that purified MEI-1/MEI-2 complexes preferentially sever at intersections between two microtubules and directly bundle microtubules in vitro. These activities could promote parallel/antiparallel microtubule organization in meiotic spindles.

APA, Harvard, Vancouver, ISO, and other styles

37

Liu, Fa Sheng, Yong Lu Zhong, Rui Xu, Lin Guo Chen, and Yong Jun Xia. "Test and Research for Mercury Emission of Boilers in 700 MW Units." Applied Mechanics and Materials 672-674 (October 2014): 1514–18. http://dx.doi.org/10.4028/www.scientific.net/amm.672-674.1514.

Full text

Abstract:

In this paper, the conversion process and the existing forms of mercury in the course of coal firing are first analyzed, and different methods to measure mercury are introduced; To assess the mercury emission levels of boilers in large power plants, through testing the mercury content in combustion products of the boiler in 700 MW unit under different loads in one power plant of Jiangxi Province, we analyzed the formation distribution of mercury emissions and the effect of low temperature economizer on the mercury concentration before and after the ESP, and acquired the mercury emission characteristics of 700 MW boiler. In study, we found that mercury in the coal burnt in 700 MW boiler was mainly discharged in the form of gas, with a small amount existing in burnt solids. The change of gaseous mercury before and after the ESP is not obvious, but the concentration of bivalent mercury is higher than that of zero-valent mercury; and more than 90% of the particulate mercury is removed. The low temperature economizer in operation can obviously reduce the concentration of mercury in flue gas at the ESP outlet by 30.8%.

APA, Harvard, Vancouver, ISO, and other styles

38

Matsumoto, Takahiko, Hiroyuki Matsuura, and Fumitaka Tsukihashi. "Oxidation and Evaporation Behaviors of Cr, Cu and As During Incineration of Wood Treated by Chromated Copper Arsenate Preservative." High Temperature Materials and Processes 31, no. 4-5 (October 30, 2012): 559–68. http://dx.doi.org/10.1515/htmp-2012-0093.

Full text

Abstract:

AbstractWoody materials treated by chromated copper arsenate (CCA) preservative containing copper, chromium and arsenic had been widely used, and thus it is anticipated that a lot of wood waste treated by CCA will be generated as the industrial waste in the future. The environmental pollution by the released heavy metals becomes a serious problem when the wood treated by CCA was incinerated inadequately. There needs the investigation for the behaviors of heavy metals during incineration of wood treated by CCA.The wood sample treated by CCA was incinerated at temperature range between 873 and 1673 K with the oxygen partial pressure between 0.21 and 0.40 atm completely. The proportion of evaporated arsenic increased with increasing temperature and most of arsenic evaporated at about 1600 K. It was suggested that arsenic evaporated as As2O3 or As4O6 during the incineration. On the other hand, most of copper and chromium remained in the bottom ash. The evaporation behaviors of arsenic largely depended on the incineration temperature, while the effects of the oxygen partial pressure of inlet gas and gas flow rate on those were small. Powder XRD analysis of bottom ash revealed that copper and chromium existed as CuCr2O4 and CuCrO2. CuCr2O4 was mainly contained in the bottom ash incinerated at temperature below 1273 K, whereas the ratio of CuCrO2 increased with increasing incineration temperature above 1273 K. Therefore, most of copper and chromium were bivalent and trivalent, respectively, in the bottom ash, and some copper was converted to a monovalent over 1273 K. Almost all arsenic was contained as pentavalent Cu3(AsO4)2, and arsenic was not identified in bottom ash incinerated at temperature above 1273 K.

APA, Harvard, Vancouver, ISO, and other styles

39

Frutos, Alejandro A., Luis F. Sala, Graciela M. Escandar, Juan Manuel Salas Peregrin, and Manuel Gonzalez Sierra. "Complex formation between D-lactobionate and bivalent metal ions. Studies in solution and in the solid state." Canadian Journal of Chemistry 75, no. 4 (April 1, 1997): 405–13. http://dx.doi.org/10.1139/v97-046.

Full text

Abstract:

The equilibrium reactions between deprotonated D-lactobionic acid (4-O-β-D-galactopyranosyl-D-gluconic acid) and cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II), and mercury(II) have been studied by potentiometric and spectrophotometric methods in aqueous solution. All measurements have been carried out at a temperature of 20.0 ± 0.1 °C and at an ionic strength of 0.100 M (NaNO3) with the corresponding stability constants calculated by applying computational methods. The interactions between the proposed cations with deprotonated D-lactobionic acid were compared with those corresponding to D-gluconic acid. Compounds of type: Co(C12H21O12)2•2H2O•C2H5OH, Ni(C12H21O12)2•2H2O•C2H5OH, Cu(C12H21O12)2•2H2O•C2H5OH, Zn(C12H21O12)2•2H2O•C2H5OH, and Cd(C12H21O12)2•2H2O•0.5C2H5OH have been isolated. These metal–sugar salts were characterized by elemental, thermogravimetric, and susceptibility analyses and FT-IR, UV–visible absorption, diffuse reflectance, and 13C NMR spectroscopies. Keywords: D-lactobionate, metal complexes, equilibrium constants, potentiometry, solid state studies.

APA, Harvard, Vancouver, ISO, and other styles

40

Qiao, Shuang, Deng Lu Hou, Qian Zhang, and Cong Mian Zhen. "Structure, Magnetic and Transport Properties of Mn_xGe_1-x." Advanced Materials Research 47-50 (June 2008): 570–74. http://dx.doi.org/10.4028/www.scientific.net/amr.47-50.570.

Full text

Abstract:

Ge1-xMnx (x=0.05, 0.07, 0.11, 0.15, 0.19, 0.23, 0.26, 0.29) thin films were prepared by magnetron sputtering. All the films had a Ge cubic structure, and no indication of a secondary phase was found in any sample using X-ray diffraction (XRD). The crystal lattice constant increases with the Mn concentration, in accordance with Vegard's law. No films show clear magnetic domain structure under a magnetic force microscope (MFM). Atom force microscope (AFM) measurements show that all films have a uniform particle size distribution, and a columnar growth pattern. X-ray photoelectron spectroscopy (XPS) measurements indicate that the Mn atoms are not singlely in the bivalent. Electrical transport properties show that the resistance of the films increases with increasing Mn concentration, suggesting that the Mn ions are in deep-level acceptor states, while resistance decreases with increasing temperature, which is a typical semiconductor property.

APA, Harvard, Vancouver, ISO, and other styles

41

Dongellini, Matteo, Paolo Valdiserri, Claudia Naldi, and Gian Luca Morini. "The Role of Emitters, Heat Pump Size, and Building Massive Envelope Elements on the Seasonal Energy Performance of Heat Pump-Based Heating Systems." Energies 13, no. 19 (September 30, 2020): 5098. http://dx.doi.org/10.3390/en13195098.

Full text

Abstract:

The influence of emitters, heat pump size and building envelope thermal inertia was investigated on the energy consumption of a heat pump-based heating system with a numerical study performed with the dynamic software TRNSYS. An algorithm based on a Thermal Inertia Control Logic (TICL), which can exploit the capability of the building envelope to store thermal energy, has been applied. When the proposed algorithm is employed, the indoor air temperature set-point is increased when the outdoor temperature is larger than the bivalent temperature of the building-heat pump system. Different configurations of the heating system were simulated considering either convective (fan-coil) or radiant (radiant floor) emitters coupled to a variable-speed air-to-water heat pump. Simulations have been carried out considering a reference building derived from the IEA SHC Task 44 and evaluating the influence of the proposed control logic on both the heat pump seasonal energy performance and the internal comfort conditions perceived by the building users. The obtained results highlight how the introduced TICL can guarantee the use of downsized heat pumps, coupled to radiant emitters, with a significant enhancement of the seasonal performance factor up to 10% and a slight improvement of comfort conditions. On the other hand, when convective terminal units are considered the proposed logic is not effective and the overall energy consumption of the system increases up to 15%.

APA, Harvard, Vancouver, ISO, and other styles

42

Xie, De Hua. "Study on Cu²⁺ Removal from Water via an Cation Exchange Membrane." Applied Mechanics and Materials 253-255 (December 2012): 954–59. http://dx.doi.org/10.4028/www.scientific.net/amm.253-255.954.

Full text

Abstract:

The removal of Cu2+ in water via an ion-exchange membrane under no external voltage condition was studied in the research, and effects such as Cu2+ concentration, concentration of compensation potassium ions, water stirring speed, temperature and hydraulic retention time (HRT) on the removal efficiency of Cu2+ were also investigated. The results showed that when the initial concentration of bivalent ion Cu2+ was 0.0787mmol/L （5mg/L）, under the experimental conditions of the water temperature at 25 °C , the HRT was 6h, the hydraulic mixing speed was 600±25rpm, and the concentration of the compensation ion K+ was 10 times as that of Cu2+, and the removal efficiency of Cu2+ could be achieved 85%. In addition, using the same equipments, when the inlet concentration of Cu2+ increased to 0.787mmol/L (50mg/L), the removal efficiency would be decreased to 76%; while the ratio of concentration of compensation potassium ions to that of inlet Cu2+ is larger than 20, the removal efficiency would not change significantly as the ratio continued increasing; the removal efficiency would be decreased to 60% when lowering the stirring speed to 300±25rpm; the removal efficiency would be decreased to 68% when lowering the temperature to 15+1 °C; the removal rate was no significant change when the hydraulic retention time (HRT) from 6h to 12h.

APA, Harvard, Vancouver, ISO, and other styles

43

Morton, L. F., A. R. Peachey, L. S. Zijenah, A. H. Goodall, M. J. Humphries, and M. J. Barnes. "Conformation-dependent platelet adhesion to collagen involving integrin alpha 2 beta 1-mediated and other mechanisms: multiple alpha 2 beta 1-recognition sites in collagen type I." Biochemical Journal 299, no. 3 (May 1, 1994): 791–97. http://dx.doi.org/10.1042/bj2990791.

Full text

Abstract:

Platelet adhesion has been measured to type-I monomeric collagen, collagen fibres, alpha 1(I) and alpha 2(I) chains and the chain fragments alpha 1(I)CB3, alpha 1(I)CB6, alpha 1(I)CB7 and alpha 1(I)CB8, and alpha 2(I)CB3,5 and alpha 2(I)CB4. Little if any adhesion occurred to any denatured species at 37 degrees C, demonstrating the importance of the collagen helix. However, on coating at 4 degrees C to promote helix formation, and assaying at room temperature to avoid denaturation, adhesion was observed to both alpha-chain types and all fragments, the exact level of which depended on the identity of the species in question. Adhesion was strongly Mg(2+)-dependent. Antibodies against the integrin alpha 2 beta 1 partially inhibited adhesion to alpha-chains and all fragments except alpha 1(I)CB6, indicating a wide distribution of alpha 2 beta 1-binding sites in the collagen molecule. ‘Activation-dependent’ adhesion to monomeric collagen, totally secondary to alpha 2 beta 1-mediated adhesion, involved at least two mechanisms, one mediated by integrin alpha IIb beta 3 and insensitive to prostaglandin E1, the other inhibitable by prostaglandin E1 but independent of integrin alpha IIb beta 3. alpha IIb beta 3-mediated adhesion to fragments was, at least in part, independent of the alpha 2 beta 1-mediated adhesion. Adhesion to fibres was largely bivalent-cation-independent with only minor involvement of integrin alpha 2 beta 1. Some alpha IIb beta 3-mediated adhesion occurred but was independent of any alpha 2 beta 1-initiated adhesion. Total ‘activation-dependent’ adhesion to fibres was less than to monomeric collagen. Affinity chromatography revealed bivalent-cation-independent binding to fibres of three main platelet surface proteins, 90, 150 and 190 kDa in size.

APA, Harvard, Vancouver, ISO, and other styles

44

Cui, Hai Rong, Ming Li Sun, and Xue Feng Wang. "Kerosene Based Magnetic Fluid Used in Magnetic Fluid Inclination Sensor." Advanced Materials Research 211-212 (February 2011): 411–15. http://dx.doi.org/10.4028/www.scientific.net/amr.211-212.411.

Full text

Abstract:

Kerosene based magnetic fluid which use kerosene as carrier liquid is characterized by better liquidity and higher magnetization which is qualified enough to use in magnetic fluid based inclination sensor. This paper provides several preparative parameters to control the physical property of kerosene based magnetic fluid during manufacture processing which use ferrous chloride and ferric chloride as forerunner reaction mass. The results show that the proper consistency of ferrous chloride and ferric chloride is 0.6mol/L. Secondly, the saturation magnetization of magnetic nano-particles is highest when the molar ratio between trivalent iron ion and bivalent iron ion is equal to 1.75. Thirdly, the proper reacted temperature is between 60~80°C and pH value should be controlled in a weak alkaline situation while six hours should be necessary for surfactant encapsulated enough around the magnetic nano-particles surface. At last, the saturation magnetization of kerosene based magnetic fluid increases with the increment of density and viscosity of magnetic fluid.

APA, Harvard, Vancouver, ISO, and other styles

45

Karshiev, B. N., А. R. Seytnazarov, U. K. Alimov, Sh S. Namazov, A. M. Reymov, and A. A. Rasulov. "Purification of wet process phosphoric acid by desulfurization and ammonization." Voprosy Khimii i Khimicheskoi Tekhnologii, no. 1 (January 2021): 24–34. http://dx.doi.org/10.32434/0321-4095-2021-134-1-24-34.

Full text

Abstract:

We studied the processes of desulfurization of phosphoric acid obtained by wet process from washed and roasted concentrate and subsequent purification of acid from bivalent and trivalent metals and fluorine via partial ammonization (at pH of 2 to 4). Purified ammoniated slurry containing 16.96% P2O5, 8.06% N, 0.09% CaO, 0.58% MgO, 0.004% Fe2O3, 0.031% A12O3, 0.78% SO3 and 0.52% F was fabricated by the removal of precipitates at the stages of desulfurization and partial ammonization. The rheological properties of ammoniated slurry with 40% moisture were studied. When the temperature is increased from 40 to 800C, both the density and viscosity decrease from 1.395 to 1.365 g cm–3 and from 80.8 to 48.7 cP, respectively. Ammoniated suspension with pH of 5.5 and 8.5 was applied to prepare mono- and diammonium phosphates with the ratio P2O5:N of 52:14 and 48:18, respectively. The sludge obtained after desulfurization and ammonization processes can be used as a slow-release fertilizer.

APA, Harvard, Vancouver, ISO, and other styles

46

Li, Jie, Yang-Ming Lu, Qing-Hao Yang, and Cheng-Fu Yang. "Effects of removing temperature of reduction gas on the luminescence characteristics of Li2BaSiO4:0.003EU2+ green phosphor." International Journal of Modern Physics B 34, no. 22n24 (August 26, 2020): 2040159. http://dx.doi.org/10.1142/s0217979220401591.

Full text

Abstract:

We had successfully synthesized green-emitting phosphors based on Li2BaSiO4 material activated by bivalent europium ions (Eu[Formula: see text]) using a solid-state reaction method in a reducing gas environment and investigated their luminescence properties. The Li2BaSiO4:0.003Eu[Formula: see text] (LSB-Eu) phosphors were synthesized at 850[Formula: see text]C for 1 h, and the reduction gas was removed at 500[Formula: see text]C, 600[Formula: see text]C, 700[Formula: see text]C and 800[Formula: see text]C, respectively. XRD pattern showed that the Li2BaSiO4, Ba2SiO4 and Li4SiO4 phases were observed in the synthesized Li2BaSiO4 composition. As the reduction gas was removed at 800[Formula: see text]C, the LSB-Eu phosphor emitted a weak red light rather than a green light. Two weak emission peaks were found at about 588 nm and 613 nm corresponding to [Formula: see text] and [Formula: see text] transitions. As temperature to remove the reduction gas was lower than 800[Formula: see text]C, the emission spectra of LSB-Eu phosphors reveled a broad peak centered at 501 nm, which emitted a green color. The intensity of photoluminescence excitation (PLE) photoluminescence emission (PL) spectra increased as the removing temperature was decreased from 700[Formula: see text]C to 500[Formula: see text]C and saturated at 500[Formula: see text]C. These results show that LSB-Eu can be a noteworthy candidate of green-emitting phosphor for the investigation of white light-emitting diodes (WLEDs).

APA, Harvard, Vancouver, ISO, and other styles

47

Zhao, Gang, Hai Rong Cui, Qiu Li Ding, Xu Feng Wang, Shi Xi Tian, and Zhuo Ping Wang. "Parameters Control for Properties of Ferrofluid Used in Series Ferrofluid Sensor." Applied Mechanics and Materials 248 (December 2012): 594–98. http://dx.doi.org/10.4028/www.scientific.net/amm.248.594.

Full text

Abstract:

Series ferrofluid based sensors are novel sensors which use ferrofluid as inductive core to measure signals. The physical properties of ferrofluid affect mostly on performance parameter of these series sensors. There is several generality regularity for ferrofluid appliedd in series sensors. This paper analyses the generality of parameter controlling for properties of ferrofluid used in series ferrofluid sensors. The working area of magnetization curve of ferrofluid used in series sensors should be in its linear area where the permeability of ferrofluid is considered as a constant. The magnetic nano-particles generally obtained by reaction of ferrous chloride and ferric chloride. With the increment of viscosity and density of ferrofluid, the saturation magnetic intensity of ferrofluid increases. The concentration of reacted solution is better to be 0.6mol/L. Saturation magnet intensity of magnetic nano-partcles is highest as the molar ratio of trivalent iron ion to bivalent iron ion is equal to 1.75. The reacted temperature is better between 65~80°C while PH value of solution is in a weak alkaline state.

APA, Harvard, Vancouver, ISO, and other styles

48

Borst, Fabian, Nina Strobel, Thomas Kohne, and Matthias Weigold. "Investigating the Electrical Demand-Side Management Potential of Industrial Steam Supply Systems Using Dynamic Simulation." Energies 14, no. 6 (March 10, 2021): 1533. http://dx.doi.org/10.3390/en14061533.

Full text

Abstract:

The increasing share of volatile, renewable energies, such as wind and solar power, leads to challenges in the stabilization of power grids and requires more flexibility in future energy systems. This article addresses the flexibilization of the consumer side and presents a simulation-based method for the technical and economic investigation of energy flexibility measures in industrial steam supply systems. The marketing of three different energy-flexibility measures—bivalence, inherent energy storage and adjusting process parameters—both at the spot market and at the balancing power market, are investigated from a technical as well as an economic point of view. Furthermore, the simulation-based methodology also considers pressure and temperature fluctuation induced by energy-flexibility measures. First, different energy-flexibility measures for industrial steam supply systems are introduced. Then, the physical modeling of the steam generation, distribution, and consumption as well as measure-specific control strategies will be discussed. Finally, the methodology is applied to a steam supply system of a chemical company. It is shown that the investigated industrial steam supply system shows energy-flexibility potentials up to 10 MW at peak and an annual average of 5.6 MW, which highly depend on consumer behavior and flexibility requirements.

APA, Harvard, Vancouver, ISO, and other styles

49

Prodromou, M., and I. Pashalidis. "Copper(II) removal from aqueous solutions by adsorption on non-treated and chemically modified cactus fibres." Water Science and Technology 68, no. 11 (October 25, 2013): 2497–504. http://dx.doi.org/10.2166/wst.2013.535.

Full text

Abstract:

The adsorption efficiency of a biomass by-product (cactus fibres) regarding the removal of copper(II) from aqueous solutions has been investigated before and after its chemical treatment. The chemical treatment of the biomass by-product included phosphorylation and MnO2-coating. The separation/removal efficiency has been studied as a function of pH, Cu(II) concentration, ionic strength, temperature and contact time. Evaluation of the experimental data shows that the MnO2-coated product presents the highest adsorption capacity, followed by the non-treated and phosphorylated material. Regarding the effect of ionic strength/salinity on the adsorption, in contrast to the removal efficiency of the phosphorylated product, which is significantly affected, the MnO2-coated and non-treated material don't show any effect, indicating the formation of inner-sphere surface complexes. The adsorption reaction is in all cases endothermic and relatively fast, particularly the adsorption on the MnO2-coated product. The results of the present study indicate that for the removal of bivalent metal-ions from contaminated waters the MnO2-coated material is expected to be the most effective adsorbent and an alternative to MnO2 resins for the treatment of environmentally relevant waters.

APA, Harvard, Vancouver, ISO, and other styles

50

Wendroth, S., and H. U. Seitz. "Characterization and localization of progesterone 5α-reductase from cell cultures of foxglove (Digitalis lanata EHRH)." Biochemical Journal 266, no. 1 (February 15, 1990): 41–46. http://dx.doi.org/10.1042/bj2660041.

Full text

Abstract:

Progesterone 5 alpha-reductase, which catalyses the reduction of progesterone to 5 alpha-pregnane-3,20-dione, was isolated and characterized from cell cultures of Digitalis lanata (foxglove). Optimum enzyme activity was observed at pH 7.0, and the enzyme had an apparent Km value of 30 microM for its substrate progesterone. The enzyme needs NADPH as reductant, which could not be replaced by NADH. For NADPH, the apparent Km value is 130 microM. The optimum temperature was 40 degrees C; at temperatures below 45 degrees C, the product 5 alpha-pregnane-3,20-dione was reduced by a second reaction to 5 alpha-pregnan-3 beta-ol-20-one. Progesterone 5 alpha-reductase activity was not dependent on bivalent cations. In the presence of EDTA, 0.1 mM-Mn2+ had no influence on enzyme activity, whereas 0.1 mM-Ca2+, -Co2+ and -Zn2+ decreased progesterone 5 alpha-reductase activity. Only 0.1 mM-Mg2+ was slightly stimulatory. EDTA and thiol reagents such as dithiothreitol stimulate progesterone 5 alpha-reductase activity. By means of linear sucrose gradient fractionation of the cellular membranes, progesterone 5 alpha-reductase was found to be located in the endoplasmic reticulum.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Temperatura bivalente'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles