scholarly journals Effect of Potential, Temperature, and Fluoride Ions on the Repassivation Kinetics of Titanium in Phosphate Buffered Saline Solution with the Photon Rupture Method

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Masatoshi Sakairi ◽  
Hiroomi Miyata ◽  
Tatsuya Kikuchi ◽  
Hideaki Takahashi
Keyword(s):  
Saline Solution ◽  
Film Formation ◽  
Electrochemical Techniques ◽  
Potential Temperature ◽  
Solution Temperature ◽  
Fluoride Ions ◽  
Rapid Dissolution ◽  
Phosphate Buffered Saline ◽  
Kinetics Of ◽  
Repassivation Kinetics

The effect of the applied potentials, temperature, and F− ions on the localized repassivation kinetics of titanium was investigated by the photon rupture method, PRM, and electrochemical techniques in phosphate buffered saline solution. The log⁡ I versus log⁡ t plots after laser beam irradiation showed a rapid increase, then a decrease with a slope of about −1.5, which is steeper than that expected from high field oxide film formation theory, suggesting that the repassivation of titanium is a combination of electrochemical and chemical reactions. The repassivation current increases with increases in the applied potential and addition of F− ions, while solution temperature does not influence the repassivation kinetics. The effect of F− ions on the repassivation kinetics can be explained by localized pH changes caused by very rapid dissolution of titanium when titanium was exposed to PBS solution.

scholarly journals DC and AC Conductivity, Biosolubility and Thermal Properties of Mg-Doped Na2O–CaO–P2O5 Glasses

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2626
Author(s):  
Natalia Anna Wójcik ◽  
Sharafat Ali ◽  
Jakub Lech Karczewski ◽  
Bo Jonson ◽  
Michał Bartmański ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Saline Solution ◽  
Glass Structure ◽  
Glass Network ◽  
Bioactive Glasses ◽  
Dc And Ac Conductivity ◽  
Impedance Spectroscopy Technique ◽  
Mg Content ◽  
Phosphate Buffered Saline ◽  
Mg Doped

Bioactive glasses have recently been extensively used to replace, regenerate, and repair hard tissues in the human body because of their ability to bond with living tissue. In this work, the effects of replacing Na2O with MgO on the electrical, biosolubility, and thermal properties of the target glass 10Na2O–60P2O5–30CaO (in mol%) were investigated. The electrical properties of the glasses were studied with the impedance spectroscopy technique. At 473 K, DC conductivity values decreased from 4.21 × 10−11 to 4.21 × 10−12 S cm−1 after complete substitution of MgO for Na2O. All samples had a similar activation energy of the DC conduction process ~1.27 eV. Conduction mechanisms were found to be due to hop of ions: Na+, Mg2+, and probable H+. FTIR analysis showed that, as the Mg content increased, the Q2 unit (PO2−) shifted towards higher wavenumbers. The proportion of Q3 unit (P2O5) decreased in the glass structure. This confirmed that the replacement of Na+ by Mg2+ was accompanied by concurrent polymerization of the calcium–phosphate glass network. The biosolubility test in the phosphate-buffered saline solution showed that the magnesium addition enhanced the biosolubility properties of Na2O–CaO–P2O5 glasses by increasing their dissolution rate and supporting forming CaP-rich layers on the surface. The glass transition temperature increased, and thermal stability decreased substantially upon substitution of Na2O by MgO.

scholarly journals Post-hatching development of bovine embryos in vitro: the effects of tunnel preparation and gender

Zygote ◽  
2011 ◽  
Vol 20 (2) ◽  
pp. 123-134 ◽  
Author(s):  
Grazieli Marinheiro Machado ◽  
Ester Siqueira Caixeta ◽  
Carolina Madeira Lucci ◽  
Rodolfo Rumpf ◽  
Maurício Machaim Franco ◽  
...  
Keyword(s):  
Gene Expression ◽  
Morphological Characteristics ◽  
Tunnel Construction ◽  
Agarose Gel ◽  
Male And Female ◽  
Embryo Size ◽  
And Gender ◽  
Phosphate Buffered Saline ◽  
Kinetics Of

SummaryThe objective of this study was to compare morphological characteristics, kinetics of development, and gene expression of male and female IVP embryos that were cultured until day (D)15 (fertilization = D0), using either phosphate-buffered saline (PBS) or Milli-Q water (MQW) to dilute the agarose gel used for tunnel construction. On D11, embryos (n = 286) were placed in agarose gel tunnels diluted in PBS and MQW. Embryos were evaluated for morphology, and embryo size was recorded on D11, D12.5, D14 and D15. Then, embryos were sexed and used for gene expression analyses (G6PD, GLUT1, GLUT3, PGK1, PLAC8, KRT8, HSF1 and IFNT). The percentage of elongated embryos at D15 was higher (p < 0.05) in the PBS (54%) than in the MQW (42%) gel. However, embryos produced in MQW were bigger (p < 0.05) and had a lower expression of GLUT1 (p = 0.08) than those cultured in PBS. There was a higher proportion of male than female embryos at D15 in both treatments, MQW (65% vs. 35%; p < 0.05) and PBS (67% vs. 33%; p < 0.05); however, embryo size was not significantly different between genders. Moreover, D15 female embryos had greater expression of G6PD (p = 0.05) and KRT8 (p = 0.03) than male embryos. In conclusion, the diluent used for tunnel construction affected embryo development in the post-hatching development (PHD) system, and the use of MQW was the most indicative measure for the evaluation of embryo quality. Male and female embryos cultured from D11 to D15, either in an MQW or PBS agarose gel, demonstrated similar development but different gene expression.

The kinetics of Ge lateral overgrowth on SiO2

MRS Advances ◽  
2015 ◽  
Vol 1 (23) ◽  
pp. 1703-1708 ◽  
Author(s):  
M. Yako ◽  
N. J. Kawai ◽  
Y. Mizuno ◽  
K. Wada
Keyword(s):  
Growth Kinetics ◽  
Growth Rates ◽  
Growth Process ◽  
Theoretical Calculations ◽  
Film Formation ◽  
Lateral Overgrowth ◽  
Flat Film ◽  
The Difference ◽  
Kinetics Of

ABSTRACTThe kinetics of Ge lateral overgrowth on SiO2 with line-shaped Si seeds is examined. The growth process is described by the difference between the growth rates of Ge on (100) planes (GR100) and <311> facets (GR311). The theoretical calculations well reproduce the growth kinetics. It is shown that narrowing the line-seeds helps Ge coalescence and flat film formation.

scholarly journals Chlorine and Chlorinated Compounds Removal from Industrial Wastewater Discharges: A Review

2021 ◽  
Vol 20 (3) ◽  
Author(s):  
Mohammad Al-Hwaiti ◽  
Hamidi Abdul Aziz ◽  
Mohd Azmier Ahmad ◽  
Reyad Al-Shawabkeh
Keyword(s):  
Industrial Wastewater ◽  
Electrochemical Techniques ◽  
Parent Compound ◽  
Water Soluble ◽  
Human Beings ◽  
Catalytic Method ◽  
Chlorinated Compounds ◽  
Water Treatment Process ◽  
Chlorine Removal ◽  
Kinetics Of

Adsorption techniques for industrial wastewater treatment rich in heavy metals and aqueous solutions of water-soluble such as Cl−, F−, HCO3−, NO3−, SO2−4, and PO3−, often include technologies for toxicity removals. The recent advancement and technical applicability in the treatment of chlorine and chlorinated compounds from industrial wastewater are reviewed in this article. Chlorine and chlorinated compounds are among the common discharged constituents from numerous industries. They can be carcinogenic or naturally toxic and can pose issues to aquatic ecosystems and human beings. Thus, elimination of chlorides and chlorinated compounds from water or wastewater is inevitable to get rid of the problem. Several techniques are being applied for the reduction of chlorine and chlorinated compounds in water. These include biodegradation, photochemical, adsorption, chemical, electrochemical, photo-electrochemical, membrane, supercritical extraction and catalytic method. Chlorine can react with various organic and inorganic micro-pollutants. However, the potential reactivity of chlorine for specific compounds is small, and only minor variations in the structure of the parent compound are anticipated in the water treatment process under typical conditions. This paper reviews different techniques and aspects related to chlorine removal, the types of chlorine species in solution and their catalyst, chlorine fate and transport into the environment, electrochemical techniques for de-chlorination of water, kinetics, mechanisms of reduction of chlorinated compounds, and kinetics of the electrochemical reaction of chlorine compounds. Keywords: Industrial waste, Kinetics, Wastewater, Water purification

scholarly journals PECULIARITIES OF PROCESS KINETICS OF FORMING CATHODE MATERIAL OF COMPOSITION LiХLaYMn1-YO2(C60)n FOR LITHIUM – ION BATTERY

2019 ◽  
Vol 62 (11) ◽  
pp. 99-105
Author(s):  
Ekaterina S. Guseva ◽  
Svetlana S. Popova
Keyword(s):  
Lithium Ion ◽  
Ion Concentration ◽  
Redox Activity ◽  
Solution Temperature ◽  
Stable Phase ◽  
Potential Range ◽  
Unusual Structure ◽  
Kinetics Of ◽  
New Phase ◽  
Mno2 Electrode

The effect of the magnitude of cathodic polarization and the temperature of a solution of lanthanum salicylate on the kinetics of the formation of elecrode LаyMn1-yO2 has been described. It has been established that two phases are formed on the electrode: the phase of the solid solution of the introduced lanthanum in MnO2 at potentials negative -2.5V turns into a new phase LаyMn1-yO2; last on the curve Eб/т-Ек the potential delay characteristic of the process of forming a new phase with an independent crystal lattice corresponds. Thus, to obtain a time-stable phase of the introduction of lanthanum into the structure of the electrode LаyMn1-yO2 the potential range from –2.9 V to –2.5 V can be recommended. The influence of the solution temperature on the kinetic characteristics of the process is ambiguous and is associated with a change in the degree of disorder in the structure of the forming phase at the boundary MnO2 electrode/solution (La3+), which hampers diffusion of ions La3+ into the electrode and leads to a decrease in ion concentration La3+, involved in the act of electrochemical introduction and, accordingly, to a decrease in the value of i (0). At temperatures above 10 °С the structure is stabilized and the characteristics (k, i (0)) increase. The composition of the formed phases is determined LixMnO2, LayMn1-yO2, LixLayMn1-yO2, current-free chronopotentiometry method calculated on the basis of equilibrium potentials Ep of these phases with pulsed galvanostatic polarization mode. Stability formed in the structure of MnO2 electrode chemical compounds of lanthanum was established. The activating effect of fullerene additives С60 composed of modified lanthanum LаyMn1-yO2 electrodes due to the high redox activity and the unusual structure of the molecules С60. Data on the effect of modified MnO2 electrodes on their potentials in an open circuit and during polarization in the working solution are in good agreement in terms of increasing the capacity of lithium with the results of cycling LiхMnO2, LiхLayMn1-yO2, LiхLayMn1-yO2-σ(C60)n in galvanostatic mode. The results of galvanostatic cycling showed that the discharge capacity of the electrodes increases in the series: LixMnO2 > LixLayMn1-yO2 > LiхLayMn1-yO2-σ(C60)n. With the help of cyclic chronovamperometry a good reversibility for LiхLayMn1-yO2-σ(C60)n electrode was established.

scholarly journals Modified/Unmodified Nanoparticle Adsorbents of Cellulose Origin With High Adsorptive Potential for Removal of Pb(II) From Aqueous Solution

2017 ◽  
Vol 13 (27) ◽  
pp. 425
Author(s):  
Azeh Yakubu ◽  
Gabriel Ademola Olatunji ◽  
Folahan Amoo Adekola
Keyword(s):  
Aqueous Solution ◽  
Adsorption Capacity ◽  
Contact Time ◽  
Adsorption Process ◽  
Correlation Coefficients ◽  
Solution Temperature ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Kinetics Of Adsorption ◽  
Kinetics Of

This investigation was conducted to evaluate the adsorption capacity of nanoparticles of cellulose origin. Nanoparticles were synthesized by acid hydrolysis of microcrystalline cellulose/cellulose acetate using 64% H3PO4 and characterized using FTIR, XRD, TGA-DTGA, BET and SEM analysis. Adsorption kinetics of Pb (II) ions in aqueous solution was investigated and the effect of initial concentration, pH, time, adsorbent dosage and solution temperature. The results showed that adsorption increased with increasing concentration with removal efficiencies of 60% and 92.99% for Azeh2 and Azeh10 respectively for initial lead concentration of 3 mg/g. The effects of contact time showed that adsorption maximum was attained within 24h of contact time. The maximum adsorption capacity and removal efficiency were achieved at pH6. Small dose of adsorbent had better performance. The kinetics of adsorption was best described by the pseudo-second-Order model while the adsorption mechanism was chemisorption and pore diffusion based on intra-particle diffusion model. The isotherm model was Freundlich. Though, all tested isotherm models relatively showed good correlation coefficients ranging from 0.969-1.000. The adsorption process was exothermic for Azeh-TDI, with a negative value of -12.812 X 103 KJ/mol. This indicates that the adsorption process for Pb by Azeh-TDI was spontaneous. Adsorption by Azeh2 was endothermic in nature.

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