scholarly journals On the absorption and scattering of γ-rays

1924 ◽  
Vol 106 (735) ◽  
pp. 8-19 ◽  
Keyword(s):  
Absorption Coefficient ◽  
Experimental Determination ◽  
Atomic Absorption ◽  
Atomic Number ◽  
Apparent Absorption ◽  
Wide Range ◽  
Γ Rays

An account of an experimental determination of the comparative absorption of penetrating γ-rays by a wide range of elements has recently been given by one of us. It is the object of the present paper to consider the results somewhat more fully, especially those concerned with scattering, which was not previously discussed. The rays used were those from RaB + C after filtration through 1 cm. lead. The absorption was primarily measured in terms of aluminium, whose apparent absorption coefficient was measured directly. It was shown that the apparent atomic absorption, for the absorber in one particular position, could be represented with considerable accuracy by μ a' = a Z + b Z 4 (1) where Z is the atomic number.

Is there a “universal” MAC equation?

1990 ◽  
Vol 48 (2) ◽  
pp. 228-229
Author(s):  
Robert E. Ogilvie
Keyword(s):  
Absorption Coefficient ◽  
Atomic Absorption ◽  
Atomic Number ◽  
X Ray ◽  
Time Period ◽  
Image Position

The search for an empirical absorption equation begins with the work of Siegbahn (1) in 1914. At that time Siegbahn showed that the value of (μ/ρ) for a given element could be expressed as a function of the wavelength (λ) of the x-ray photon by the following equationwhere C is a constant for a given material, which will have sudden jumps in value at critial absorption limits. Siegbahn found that n varied from 2.66 to 2.71 for various solids, and from 2.66 to 2.94 for various gases.Bragg and Pierce (2) , at this same time period, showed that their results on materials ranging from Al(13) to Au(79) could be represented by the followingwhere μa is the atomic absorption coefficient, Z the atomic number. Today equation (2) is known as the “Bragg-Pierce” Law. The exponent of 5/2(n) was questioned by many investigators, and that n should be closer to 3. The work of Wingardh (3) showed that the exponent of Z should be much lower, p = 2.95, however, this is much lower than that found by most investigators.

Atomic Absorption Methods for the Direct Analysis of Metals and Alloys

1973 ◽  
Vol 27 (5) ◽  
pp. 335-341 ◽  
Author(s):  
Alan Walsh
Keyword(s):  
Atomic Absorption ◽  
Direct Analysis ◽  
Precise Determination ◽  
Metals And Alloys ◽  
Spectrochemical Analysis ◽  
Solid Samples ◽  
Trace Impurities ◽  
Wide Range

While atomic absorption methods of spectrochemical analysis have found a wide range of application, they have been almost entirely confined to the analysis of solutions. Solid samples for analysis have required prior solution. In recent months the situation has been transformed, and it has been demonstrated that some important metals and alloys can be analyzed directly by atomic absorption methods, which can be applied to the precise determination of major constituents and of trace impurities.

Experimental determination of the effective atomic number of inclusion tissue by spectrozonal roentgenography

2006 ◽  
Vol 40 (1) ◽  
pp. 12-15 ◽  
Author(s):  
A. S. Lelyukhin ◽  
E. A. Kornev ◽  
Yu. G. Samakaev ◽  
V. V. Kan’shin ◽  
V. I. Lipatkin
Keyword(s):  
Experimental Determination ◽  
Atomic Number ◽  
Effective Atomic Number

Experimental Determination of the Molar Absorption Coefficient of n -Hexane Adsorbed on High-Silica Zeolites

ChemPhysChem ◽  
2017 ◽  
Vol 18 (17) ◽  
pp. 2374-2380 ◽  
Author(s):  
Giorgio Gatti ◽  
Diana F. Olivas Olivera ◽  
Vittoria Sacchetto ◽  
Maurizio Cossi ◽  
Ilaria Braschi ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Experimental Determination ◽  
Molar Absorption Coefficient ◽  
High Silica ◽  
High Silica Zeolites

The Determination of Mass Flow in the Vapour-Compression Refrigerator

1935 ◽  
Vol 129 (1) ◽  
pp. 477-505 ◽  
Author(s):  
E. C. Smith
Keyword(s):  
Experimental Determination ◽  
Mass Flow ◽  
The State ◽  
Volumetric Efficiency ◽  
Coefficient Of Performance ◽  
Flow Meter ◽  
Wide Range ◽  
Liquid Portion ◽  
Vapour Compression

The paper describes an experimental determination of the mass flow of refrigerant per minute and refrigerating effect per minute in a vapour-compression refrigerator, when the state of the refrigerant at the exit from the evaporator was varied over a wide range of superheat temperatures and dryness fractions. The usual methods of measuring the flow of liquids in pipes were not suitable for the present work and a special type of flow meter, described in the text, was developed. The results obtained were not as theory would tend to suggest, but were substantially modified by practical conditions, particularly for dryness fractions between 0·97 and 0·87. The volumetric efficiency changed abruptly over this range from a higher to a lower value. The reduction was attributed to the effect of re-evaporation of. the liquid portion of the refrigerant in the compressor during the suction stroke, as it was found that the higher volumetric efficiency was obtained when the refrigerant was superheated throughout most of the delivery stroke, and the lower volumetric efficiency occurred when the state of the refrigerant on entering the compressor resulted in liquid being present in the cylinder at the end of the delivery stroke. The reduction in the volumetric efficiency resulted in a corresponding reduction in the mass flow, the refrigerating effect, and the heat rejected by the condenser per minute, and in the coefficient of performance for dryness fractions ranging between 0·97 and 0·87.

Improved determination of manganese in hair by use of a mini-autoclave and flameless atomic absorption spectrometry with Zeeman background correction: an evaluation in unexposed subjects.

1984 ◽  
Vol 30 (10) ◽  
pp. 1642-1645 ◽  
Author(s):  
O Guillard ◽  
J C Brugier ◽  
A Piriou ◽  
M Ménard ◽  
J Gombert ◽  
...  
Keyword(s):  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Human Subjects ◽  
Absorption Spectrometry ◽  
Dry Weight ◽  
Flameless Atomic Absorption ◽  
Wide Range ◽  
Flameless Atomic Absorption Spectrometry ◽  
Standard Additions

Abstract Motivated by the relatively wide range of values published hitherto, we offer a new, reliable method for determination of manganese in hair from unexposed human subjects. By using a mini-autoclave, we have developed a method that obviates loss of manganese during digestion and, thanks to use of a Teflon receptacle and rigorous methodology, contamination has been minimized. We used Zeeman flameless atomic absorption spectrometry, with the method of standard additions, for quantification. Within-run CVs for concentrations of Mn of 0.26 and 0.28 microgram/g of dry hair were 3.63 and 3.93%; the day-to-day CV for a Mn concentration of 0.29 microgram/g of dry hair was 5.84%. Mean (+/- SD) analytical recovery of Mn added to samples of hair was 104% (+/- 9.2%). The mean concentration of Mn found in the hair of 15 healthy unexposed subjects was 0.26 (+/- 0.05) microgram/g dry weight. This sensitive, reproducible procedure is suitable for use in analysis for traces of Mn in hair.

Experimental determination of gold speciation in sulfide-rich hydrothermal fluids under a wide range of redox conditions

2017 ◽  
Vol 471 ◽  
pp. 52-64 ◽  
Author(s):  
A.L. Trigub ◽  
B.R. Tagirov ◽  
K.O. Kvashnina ◽  
S. Lafuerza ◽  
O.N. Filimonova ◽  
...  
Keyword(s):  
Experimental Determination ◽  
Hydrothermal Fluids ◽  
Redox Conditions ◽  
Wide Range
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