Experiment Station Record, Volume 95, July-December, 1946 Page: 12
xii, 1033 p. ; 24 cm.View a full description of this book.
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12 - EXPERIMENT STATION RECORD [Vol. 95
are: Color-grading problems; color charts in grading work; transparent-color
standards in grading work; standards need measuring; several methods of expressing
results of color measurement (International Commission on Illumination method of
color notation, hemogeneous-heterogeneous method of color notation, Munsell method
of color notation, and relation between methods); disk colorimetry (early method,
present method, instruments, choice of disks, and conversion to Munsell notation);
application of disk colorimetry to grading problems (sample preparation and preparation
of conversion data); applications of Munsell notations in related problems; the
Kelly mask method for color matching; standard names for colors; American
Standards Association standard for the specification and description of color; colortolerance
specifications; artificial daylighting for grading work; color-vision testing;
and literature cited.
Fluorimetry: The estimation of the concentration of fluorescent pigments
from their fluorescence intensity, P. ELLINGER and M. HOLDEN (Jour. Soc. Chem.
Indus., Trans. and Common., 63 (1944), No. 4, pp. 115-121, illus. 6).-A detailed
discussion is presented on the principles of fluorimetric determinations, including the
relative accuracy of various methods, influence of concentration of the solution,
position and shape of the container, intensity and absorption of the primary light
beam, and various other factors. Both direct deflection and balancing methods were
used. The solutions studied included thiochrome, chlorophyll, uranine, riboflavin,
and quinine sulfate in various solvents.
Accelerated method for determining moisture absorption, J. Y. YEE and
R. O. E. DAVIS. (U. S. D. A.). (Indus. and Engin. Chem. Analyt. Ed., 16 (1944),
No, 8, pp. 487-490, ills. 4).-The authors point out that the ordinary procedure,
consisting essentially in exposing the samples in weighing bottles or on watch glasses
in an enclosed space over a solution designed to give the desired relative humidity,
usually produces results neither consistent nor reproducible. An accelerated method
for the moisture-absorption measurements is described, one of the essential features
of which consists in the use of a humidifying chamber provided with a four-bladed
aluminum fan rotating in a plane parallel with the surface of the humidity-standard
liquid and directly over it. Factors such as temperature, the size, depth, and number
of dishes, and the arrangement in the humidity chamber were found to influence the
final results. Careful standardization of all conditions, therefore, is essential in
order to obtain reproducible results. Devices introduced for this purpose include
sample dishes and covers of standardized form and size, an instrument for the
uniform spreading of the sample dish, and a leveling device, designed to be placed
on the sample under an additional weight of 1 kg.,. to give the sample a uniformly
smooth surface and uniform packing. Considerable time can be saved by the
accelerated method in making equilibrium moisture-absorption measurements of
fertilizers.
Determination of large amounts of manganese: Modified persulfate method,
H. D. HILLSON. (Univ. Maine). (Indus. and Engin. Chem. Analyt. Ed., 16 (1944),
No. 9, pp. 560-562).-In a study of the reaction of ammonium persulfate with
manganous salts in acid solution, it was discovered that by the addition of disodium
hydrogen phosphate, the manganese can be oxidized and the excess persulfate decomposed
by boiling. By the use of osmic acid, the permanganate may be stoichiometrically
titrated with sodium arsenite solution. These modifications adapt the
persulfate method to the accurate determination of manganese in concentrations
larger than it has been possible heretofore to deal with and extend the usefulness of
the procedure. A further necessary modification consisted in the establishment of
carefully specified conditions for the heating by which the excess persulfate is decomposed,
such that removal of the persulfate is complete without concomitant decomposition
of any of the permanganate. Full manipulative detail of the determination
is given.
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U.S. Department of Agriculture. Agricultural Research Administration. Office of Experiment Stations. Experiment Station Record, Volume 95, July-December, 1946, book, 1948; Washington D.C.. (https://digital.library.unt.edu/ark:/67531/metadc5061/m1/24/: accessed April 24, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.