scholarly journals On the atomic weight of strontium

1910 ◽  
Vol 83 (562) ◽  
pp. 277-289 ◽  
Keyword(s):  
Silver Chloride ◽  
Atomic Weight ◽  
Great Accuracy ◽  
Silver Bromide ◽  
High Degree ◽  
Supernatant Solution ◽  
Clear Supernatant

In the Bakerian Lecture for 1907, “On the Atomic Weight of Radium,” one of us described a rapid and effective method of separating the clear supernatant solution above a precipitate, say of silver chloride or silver bromide, which obviated the necessity of employing any of the ordinary methods of filtration and otherwise greatly simplified the manipulative process. As the contrivance was found convenient in practice and seemed to admit of a high degree of accuracy, we have thought it worth while to make use of it in a redetermination of the atomic weight of strontium which should seek to conform to the standard of precision prescribed by modern procedure in atomic weight estimations. Determinations of the atomic weight of strontium have been made by Stromeyer (1816), Rose (1816), Salvétat (1843), Pelouze (1845), Marignac (1858), Dumas (1859), and Richards (1894-5 and 1905). With the exception of those of Richards these estimations have no claim to great accuracy, and are therefore only of historical interest.

scholarly journals III. On the atomic weight of manganese

1883 ◽  
Vol 35 (224-226) ◽  
pp. 44-48
Keyword(s):  
Carbon Dioxide ◽  
Silver Chloride ◽  
Atomic Weight ◽  
Special Method ◽  
Its Analysis ◽  
A Current ◽  
Sulphuretted Hydrogen

Our attention has been directed for some time to a new determination of the atomic weight of manganese. This communication gives a succinct account of the results of the preliminary stages of such an inquiry, and although the further progress of the investigation may reveal some errors, still we feel convinced the final numbers can in no way differ materially from the present values, and therefore further delay in publication is unnecessary. The atomic weight of manganese has been determined by many chemists, but the resulting values vary considerably according to the special method selected. The results of the different investigators may be divided into two classes—those giving approximately 55 as the number, and those making it about 54. To the former class belong Turner, Berzelius, and Dumas, all of whom use the same method, viz., the determination of the silver chloride yielded by a weighed amount of chloride of manganese. Turner also made determinations from the analysis of the carbonate, and from the conversion of the monoxide into sulphate. Von Hauer used the same method as that employed by him in the determination of the atomic weight of cadmium, viz., the reduction of manganous sulphate to sulphide by ignition in a current of sulphuretted hydrogen. It is probable that this method is not very trustworthy, as, according to Schneider, the sulphide may be contaminated by oxysulphide. Schneider and Rawack belong to the second class of observers, the former employing the oxalate, and from its analysis calculating the atomic weight by deducting the weight of water and carbon dioxide obtained. Rawack, whose experiments were conducted in Schneider’s laboratory, weighed the water obtained by reducing manganoso-manganic oxide to manganous oxide.

A calculation of defect Gibbs energies for silver chloride and silver bromide

1987 ◽  
Vol 55 (4) ◽  
pp. 481-498 ◽  
Author(s):  
C.R. A. Catlow ◽  
J. Corish ◽  
J. H. Harding ◽  
P.W. M. Jacobs
Keyword(s):  
Silver Chloride ◽  
Silver Bromide ◽  
Gibbs Energies

Selected generalized integration techniques for analog computation

SIMULATION ◽  
1967 ◽  
Vol 9 (1) ◽  
pp. 21-28 ◽  
Author(s):  
Arthur Hausner
Keyword(s):  
Differential Equations ◽  
Rational Functions ◽  
Analog Computer ◽  
Great Accuracy ◽  
Analog Computation ◽  
Major Disadvantage ◽  
Integration Techniques ◽  
High Degree

Generalized integration is a technique for generating ex plicit functions on an analog computer by solving the appropriate differential equations they satisfy. Setting up the solution of differential equations using the parametric technique is first reviewed. Two theorems regarding the capability of linear equipment in generating sums and products are stated, and their usefulness is illustrated with examples. Applications of the technique to generating high-degree oscillatory polynomials and rational functions (which require nonlinear equipment) are also described. The major advantage of the technique is achievement of great accuracy with minimum equipment in some cases. The major disadvantage is that, with time, errors may sometimes increase and may not be bounded.

THE OXIDATION OF SUCCINATE IN EXTRACTS OF XANTHOMONAS PHASEOLI

1960 ◽  
Vol 38 (1) ◽  
pp. 481-492
Author(s):  
N. B. Madsen
Keyword(s):  
Electron Transport ◽  
Electron Transport Chain ◽  
Intact Cell ◽  
Succinic Dehydrogenase ◽  
Order Reaction ◽  
First Order ◽  
Transport Chain ◽  
Particulate Form ◽  
Supernatant Solution ◽  
Clear Supernatant

Succinoxidase and succinic dehydrogenase were found in cell-free extracts of Xanthomonas phaseoli, obtained by sonic oscillation, and remained largely in the supernatant solution after ultracentrifugation. The effect of time of exposure of the cells to sonic oscillation on cell breakage was found to follow first order reaction kinetics, as was the "solubilization" of succinic dehydrogenase and succinoxidase. It appears that the two enzymatic activities are released from the cell in a particulate form which is further fragmented on continued treatment in the sonic oscillator.The clear supernatant solution obtained after ultracentrifugation of the cell-free extract was found to contain those members of the electron transport chain which had previously been found in the intact cell, namely, flavoprotein and cytochromes b1, a1, and a2. These substances could be reduced by the addition of succinate. Malonate prevented this reduction. The effects of various inhibitors on the succinoxidase system and on succinic dehydrogenase are presented and discussed in relation to the operation of the electron transport chain in the oxidation of succinate by this organism.

Band Structure of Silver Chloride and Silver Bromide

1965 ◽  
Vol 139 (3A) ◽  
pp. A934-A940 ◽  
Author(s):  
Peter M. Scop
Keyword(s):  
Band Structure ◽  
Silver Chloride ◽  
Silver Bromide

scholarly journals The absorption in lead of the γ-rays emitted by radium and radium C

1915 ◽  
Vol 91 (630) ◽  
pp. 396-404 ◽  
Keyword(s):  
Atomic Weight ◽  
Great Accuracy ◽  
Complete Analysis ◽  
Characteristic Radiation ◽  
Anomalous Effect ◽  
Γ Radiation ◽  
Additional Information ◽  
Absorbing Material ◽  
Γ Rays ◽  
The Difference

In a previous paper by Rutherford and the author attention has been drawn to the fact that the two types of γ-radiation emitted by radium B and radium c which are exponentially absorbed by aluminium both show irregular absorption curves when lead is used as the absorbing material. The curve obtained for pure radium C was observed to fall far more rapidly than was to be expected only after traversing a thickness of 1·5cm of lead. The absorption curve in lead of the γ-rays from radium B was obtained by taking the difference between the radium (B+C) and the radium C curves. The results so obtained were not determined with very great accuracy, but they served to show that in this case, to, the absorption is not exponential , and that the absorption coefficient rapidly diminished from about μ =11(cm. -1 ) to μ =2(cm -1 ). The accuracy of the curves did not, however, permit of their complete analysis as in the case of those previously obtained for aluminium. During the course of his work on characteristic radiations Barkla has Pointed out and investigated the anomalous effect on the absorption of a characteristic radiation by an element whose atomic weight is near to that of the element which emits the radiation. His experiments were, however, confined to elements of comparatively low atomic weight. As the atomic weights of radium B and radium C can only differ by a small amount, and as they have atomic numbers differing only by unity, viz., radium B=82 and radium C=83, it seemed of importance to determine accurately the absorption curves in lead, and to examine whether any additional information can be obtained which may indicate whether the radiations emitted by radium B and radium C are characteristic of these elements and fall into the series given by Barkla.

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