Monitoring Apparent pH Value in Geopolymer Concrete Using Glass Electrode

2016 ◽  
Author(s):  
Jin Dang ◽  
Xuesong Shen ◽  
Arnaud Castel ◽  
James Aldred
Keyword(s):  
Ph Value ◽  
Glass Electrode ◽  
Geopolymer Concrete

scholarly journals The pH measurement with glass electrode in an electromagnetic field

2016 ◽  
Vol 81 (12) ◽  
pp. 1407-1414 ◽  
Author(s):  
Dragan Veselinovic ◽  
Zoran Velikic
Keyword(s):  
Electromagnetic Field ◽  
Buffer Capacity ◽  
Extreme Values ◽  
Ph Value ◽  
Radiation Power ◽  
Glass Electrode ◽  
Frequency Interval ◽  
Buffer Solutions ◽  
Ph Values ◽  
Glass Electrodes

Measurements of pH values of buffer solutions (pH 4.0, 7.0 and 10.0) and distilled water have been performed with a glass electrode in electromagnetic field at the frequency interval of 10 MHz to 200 MHz and the output power of dispersed and reflected electromagnetic radiation of 0.01 W to 3 W. In all the cases, there occurred a reduction of pH values, i.e. a "recorded pH value" was obtained. The reduction appears within the applied frequency interval reaching extreme values at specific frequencies. The reduction of the pH values increases with the radiation power and depend of the solution buffer capacity. The effect of electromagnetic field on pH value change is exerted dominantly through the influence on glass electrodes.

scholarly journals STUDIES ON PENETRATION OF DYES WITH GLASS ELECTRODE

1930 ◽  
Vol 14 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Marian Irwin
Keyword(s):  
Ph Value ◽  
Glass Electrode ◽  
Free Base ◽  
Cresyl Blue

Glass electrode measurements of the pH value of the sap of Nitella show that cresyl blue in form of free base penetrates the vacuoles and raises pH value of the sap to about the same degree as the free base of the dye added to the sap in vitro, while the dye salt dissolved in the sap does not alter its pH value. It is proved conclusively that the increase in the pH value of the sap is due only to the presence of the dye and not to some other alkaline substance. Spectrophotometric measurements show that the dye which penetrates the vacuole is chiefly cresyl blue. When the protoplasm is squeezed into the sap, the pH value of the sap is higher than that of the pure sap. Such a mixture behaves very much like the sap in respect to the dye.

scholarly journals Change of acidity of the environment in the process of decomposition of apatitis sulfuric acid

2019 ◽  
Vol 81 (1) ◽  
pp. 325-328
Author(s):  
R. F. Sabirov ◽  
A. F. Makhotkin ◽  
Yu. N. Sakharov
Keyword(s):  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Ph Value ◽  
Raw Materials ◽  
Batch Reactor ◽  
Glass Electrode ◽  
Monocalcium Phosphate ◽  
Rapid Decomposition ◽  
Ph Values ◽  
Phosphoric Acids

An experimental study of the decomposition process of Kovdorsky apatite with certain particle sizes, in a 1 dm3 batch reactor with stirring of the reaction mixture, initial phosphoric acid concentration 17% by weight, in the system: Apatite-H3PO4 – H2SO4-H2O. Sulfuric acid was introduced in stoichiometric amount at the beginning of the process. The process was carried out at a ratio L:S 2.5:1, at a temperature of 78– 82 °C. The process was monitored by the method of joint determination of sulfuric and phosphoric acids by titrimetric analysis of the composition of the reaction mixture in the presence of methyl orange, and then phenolphthalein. Determined the concentration of phosphoric acid, the concentration of excess or deficiency of sulfuric acid and the concentration of monocalcium phosphate gel were determined. The acidity of the reaction mixture was recorded according to the indications of a Ph-meter (pH-105 MA with a combined glass electrode – ESK-10603). In the system: Apatite-H3PO4-H2SO4-H2O, when analyzing the obtained experimental values of these parameters, it was shown that during the process the pH of the reaction mixture rises to pH 6.3 for about 30 minutes, and then decreases to pH 4.5–5. Comparison of the dependence of pH values on the concentration of sulfuric acid in an aqueous solution of phosphoric acid and the pH values of the reaction mixture with the corresponding concentrations of sulfuric and phosphoric acids shows that the pH value of the reaction mixture is determined by the presence in the mixture between weft product - monocalcium phosphate gel. The process of decomposition of apatite in the system Apatite-H3PO4-H2SO4-H2O proceeds in several stages. At the beginning, a rapid decomposition of phosphate raw materials with phosphoric acid and a corresponding change in the pH of the reaction mixture, associated with the accumulation of monocalcium phosphate in solution, takes place. Then there is a slow decomposition of monocalcium phosphate with sulfuric acid and a corresponding decrease in pH to 4.5–5. The pH value at the end of the process is determined by the physicochemical properties of phosphoric acid present in the reaction mixture. At all stages of the process there is a constant increase in the concentration of phosphoric acid associated with the decomposition of monocalcium phosphate gel.

scholarly journals STUDIES ON PENETRATION OF DYES WITH GLASS ELECTRODE

1930 ◽  
Vol 14 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Marian Irwin
Keyword(s):  
Methylene Blue ◽  
Partition Coefficients ◽  
Ph Value ◽  
Spectrophotometric Analysis ◽  
Glass Electrode ◽  
Methylene Blue Solution ◽  
Free Base ◽  
Azure B ◽  
Blue Solution

Glass electrode measurements of the pH value of the sap of cells of Nitella show that azure B in the form of free base penetrates the vacuoles and raises the pH value of the sap to about the same degree as the free base of the dye added to the sap in vitro, but the dye salt dissolved in the sap does not alter the pH value of the sap. It is concluded that the dye penetrates the vacuoles chiefly in the form of free base and not as salt. The dye from methylene blue solution containing azure B free base as impurity penetrates and accumulates in the vacuole. This dye must be azure B in the form of free base, since it raises the pH value of the sap to about the same extent as the free base of azure B dissolved in the sap in vitro. The dye absorbed by the chloroform from methylene blue solution behaves like the dye penetrating the vacuole. These results confirm those of spectrophotometric analysis previously published. Crystal violet exists only in one form between pH 5 and pH 9.2, and does not alter the pH value of the sap at the concentrations used. It does not penetrate readily unless cells are injured. A theory of "multiple partition coefficients" is described which explains the mechanism of the behavior of living cells to these dyes. When the protoplasm is squeezed into the sap, the pH value of the mixture is higher than that of the pure sap. The behavior of such a mixture to the dye is very much like that of the sap except that with azure B and methylene blue the rise in the pH value of such a mixture is not so pronounced as with sap when the dye penetrates into the vacuoles. Spectrophotometric measurements show that the dye which penetrates from methylene blue solution has a primary absorption maximum at 653 to 655 mµ (i.e., is a mixture of azure B and methylene blue, with preponderance of azure B) whether we take the sap alone or the sap plus protoplasm. These results confirm those previously obtained with spectrophotometric measurements.

Calcium Binding in Enamel Fluid and Driving Force for Enamel Mineralization in the Secretory Stage of Amelogenesis

1987 ◽  
Vol 1 (2) ◽  
pp. 245-251 ◽  
Author(s):  
E.C. Moreno ◽  
T. Aoba
Keyword(s):  
Dissociation Constant ◽  
Calcium Binding ◽  
Ph Value ◽  
Total Concentration ◽  
Simulation Models ◽  
Glass Electrode ◽  
Degree Of Saturation ◽  
Ionic Form ◽  
Ligand Complex ◽  
Apparent Dissociation Constant

A large portion (about 85%) of the calcium present in the fluid of porcine enamel in the secretory stage of amelogenesis appears to be in a non-ionic form. Calcium is probably bound in the fluid by peptides derived from the enzymatic degradation of the amelogenins present in the matrix or by other ligands of an as-yet-undetermined nature. The apparent dissociation constant of the hypothesized complex was determined by titration of a small aliquot of fluid (50 μL) with 10 mmol/L CaCl2 solution, adding 2 μL at a time. The initial composition of the fluid was determined analytically. The ionic calcium activity, (Ca 2+), and the pH value along the titration were determined by a specific ion and a glass electrode, respectively, with the same reference micro-electrode. The concentration of bound Ca, [B], was related to the (Ca2+) by the equation [B] = N(Ca2+)/ {K + (Ca2+)}, in which K is the dissociation constant of the Ca-ligand complex and N is the number of binding sites per liter of fluid. The values of K and N were obtained by a non-linear least-squares procedure. The value of K, 7.47 × 10-5 mol/L, indicates that the binding bond is rather weak, a feature that seems advantageous if complexed calcium acts as a reservoir and/or fine control of calcium levels in the fluid during enamel formation. The effects that the total concentration of calcium, [Ca]T, the total concentration of P, the concentration of ligand, and the pH value have on the degree of saturation (DS) were investigated by simulation models. It is concluded that the factor that most affects the DS is [Ca]T. Some physicochemical aspects of amelogenesis are discussed on the basis of present knowledge and the reported results.

Guidelines for NMR measurements for determination of high and low pKa values (IUPAC Technical Report)

2006 ◽  
Vol 78 (3) ◽  
pp. 663-675 ◽  
Author(s):  
Konstantin Popov ◽  
Hannu Rönkkömäki ◽  
Lauri H. J. Lajunen
Keyword(s):  
Ionic Strength ◽  
Ph Value ◽  
Supporting Electrolyte ◽  
Background Electrolyte ◽  
Glass Electrode ◽  
Basic Solution ◽  
Factors Affecting ◽  
External Reference ◽  
Technical Report

Factors affecting the NMR titration procedures for the determination of pKa values in strongly basic and strongly acidic aqueous solutions (2 > pH > 0 and 14 > pH > 12) are analyzed. Guidelines for experimental procedure and publication protocols are formulated. These include: calculation of the equilibrium H+ concentration in a sample; avoidance of measurement with glass electrode in highly acidic (basic) solutions; exclusion of D2O as a solvent; use of an individual sample isolated from air for each pH value; use of external reference and lock compounds; use of a medium of constant ionic strength with clear indication of the supporting electrolyte and of the way the contribution of any ligand to the ionic strength of the medium is accounted for; use of the NMR technique in a way that eliminates sample heating to facilitate better sample temperature control (e.g., 1H-coupled NMR for nuclei other than protons, GD-mode, CPD-mode, etc.); use of Me4NCl/Me4NOH or KCl/KOH as a supporting electrolyte in basic solution rather than sodium salts in order to eliminate errors arising from NaOH association; verification of the independence of the NMR chemical shift from background electrolyte composition and concentration; use of extrapolation procedures.

Comparative Labelling and Biokinetic Studies of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn)

1977 ◽  
Vol 16 (01) ◽  
pp. 30-35 ◽  
Author(s):  
N. Agha ◽  
R. B. R. Persson
Keyword(s):  
Complex Formation ◽  
Significant Influence ◽  
Room Temperature ◽  
Ph Value ◽  
Maximum Activity ◽  
Reduction Step ◽  
Labelling Yield ◽  
Different Temperatures ◽  
Kinetics Of

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).

Rhenium-188 Labeled Hydroxyapatite and Rhenium-188 Sulfur Colloid

1997 ◽  
Vol 36 (02) ◽  
pp. 71-75 ◽  
Author(s):  
S. Glatz ◽  
S. N. Reske ◽  
K. G. Grillenberger
Keyword(s):  
Synovial Fluid ◽  
Ph Value ◽  
Surgical Removal ◽  
Radiation Synovectomy ◽  
Sulfur Colloid ◽  
Target Organs ◽  
Aseptic Conditions ◽  
In Vitro Stability ◽  
Potential Use

Summary Aim: One therapeutic approach to rheumatoid arthritis and other inflammatory arthropathies besides surgical removal of inflamed synovium is radiation synovectomy using beta-emitting radionuclides to destroy the affected synovial tissue. Up to now the major problem associated with the use of labeled particles or colloids has been considerable leakage of radionuclides from the injected joint coupled with high radiation doses to liver and other non target organs. In this study we compared 188Re labeled hydroxyapatite particles and 188Re rhenium sulfur colloid for their potential use in radiation synovectomy. Methods: To this end we varied the labeling conditions (concentrations, pH-value, heating procedure) and analyzed the labeling yield, radiochemical purity, and in vitro stability of the resulting radiopharmaceutical. Results: After optimizing labeling conditions we achieved a labeling yield of more than 80% for 188Re hydroxyapatite and more than 90% for the rhenium sulfur colloid. Both of the radiopharmaceuticals can be prepared under aseptic conditions using an autoclav for heating without loss of activity. In vitro stability studies using various challenge solutions (water, normal saline, diluted synovial fluid) showed that 188Re labeled hydroxyapatite particles lost about 80% of their activity within 5 d in synovial fluid. Rhenium sulfur colloid on the other hand proved to be very stable with a remaining activity of more than 93% after 5 d in diluted synovial fluid. Conclusion: These in vitro results suggest that 188Re labeled rhenium sulfur colloid expects to be more suitable for therapeutic use in radiation synovectomy than the labeled hydroxyapatite particles.

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