scholarly journals Determination of chromium (VI) in the dust of gas treatment plants in steelmaking plants.

2020 ◽  
pp. 42-44
Author(s):  
V. A. Makarov ◽  
T. K. Savosteenko
Keyword(s):  
Hexavalent Chromium ◽  
Raw Materials ◽  
Potassium Dichromate ◽  
Least Square Method ◽  
Photometric Determination ◽  
Least Square ◽  
Photometric Method ◽  
Gas Treatment ◽  
Gas Cleaning

The requirements for the content of hexavalent chromium in cements and raw materials for its manufacture are described. The problem with the utilization of dust from gas treatment plants of metallurgical plants at metallurgical enterprises is given. The influence of the chemical composition of the dust of gas cleaning plants of metallurgical plants on the determination of hexavalent chromium is established. A method for measuring the hexavalent chromium in the dust of gas cleaning plants of metallurgical plants by the photometric method is described. A method has been developed for extracting hexavalent chromium from dust at the cleaning units of metallurgical plants for subsequent photometric determination. An extraction method has been established to prevent underestimation of the hexavalent chromium content. The determination of hexavalent chromium was based on the formation of a blue-violet complex with diphenylcarbazide. Calibration was carried out on aque solutions with a known concentration of hexavalent chromium. For the preparation of calibration solutions, potassium dichromate of chemical purity was used. The concentration of hexavalent chromium in each calibration solution was carried out by a calculation method, overlapping the entire measurement range. The measurement of optical density was carried out on a photoelectric colorimeter type KFK-3, at a wavelength of 540 nm. Analysis of the obtained calibration dependence showed a good correlation. The calibration factor was calculated using the least square method. Extraction of hexavalent chromium from the sample to be analyzed was performed with water. The reducing effect of iron was eliminated with a solution of phosphoric acid. The developed technique is used when conducting certification control of dust from gas cleaning units of metallurgical plants, as well as during research.A validation procedure was carried out. Obtained acceptable limits of repeatability and reproducibility of the method.

Automatic Flame Photometric Determination of Potassium in Fertilizers. A. Elimination of Anion Exchange Cleanup. B. Using Direct Available P2O5 Extract

1965 ◽  
Vol 48 (6) ◽  
pp. 1095-1100
Author(s):  
James P Ussary ◽  
Charles W Gehrke
Keyword(s):  
Anion Exchange ◽  
Primary Standard ◽  
Photometric Determination ◽  
Photometric Method ◽  
Potassium Salts ◽  
Commercial Fertilizer ◽  
Aoac Official ◽  
Primary Standards ◽  
Standard Grade

Abstract Three primary standard grade potassium salts, eight Magruder check samples, and 18 commercial fertilizer samples were analyzed by three methods. Primary standards gave an average recovery of 100.0% and an average range of 0.21% K20. Magruder check samples averaged 0.09% K20 higher by the modified flame photometric method than the grand averages of the STPB results on the respective Magruder reports. The modified flame photometric method averaged 0.02% K20 lower than the official flame photometric method and 0.11% K20 higher than the official STPB method on 18 commercial fertilizer samples. The automatic flame photometric method, without anion exchange cleanup, is rapid enough for routine analysis and is as accurate and precise as the AOAC official methods. The method was also applied to the direct available P205 extract. Results on three primary grade potassium salts, seven Magruder check samples, and 13 commercial fertilizer samples were as accurate and precise as the official STPB method.

X-ray Diffractometric Determination of Lattice Misfit Between γ and γ' Phases in Ni-Base Superalloys

1988 ◽  
Vol 32 ◽  
pp. 365-375 ◽  
Author(s):  
Katsumi Ohno ◽  
Hirosi Harada ◽  
Toshihiro Yamagata ◽  
Michio Yamazaki ◽  
Kazumasa Ohsumi
Keyword(s):  
Lattice Misfit ◽  
Least Square Method ◽  
Least Square ◽  
X Rays ◽  
Deconvolution Method ◽  
X Ray ◽  
Window Functions ◽  
Profile Fitting ◽  
Overlapping Peaks

AbstractThe lattice misfits between γ and γ' phases in Ni-base superalloys (single crystal) were accurately determined for filings of specimens by using both a conventional X-ray tube focusing diffractometer(CXRFD) and a synchrotron-radiation parallel beam X-ray diffractometer (SRPXRD). All reflection peaks measured with the CXRFD were in a cluster of overlapping peaks because of the very small differences in the lattice parameters of both phases and the instrumental broadening due to X-ray optics including the spectral distribution of Xray source such as CuKα doublet. The deconvolution method was applied to remove the instrumental broadening from the peaks measured with the CXRFD. The window functions for the deconvolution method were calculated from CuKα doublet reflection of Si standard by a nonlinear least-square method.The instrumental broadening of SRPXRD was much smaller than that of CXRFD since the monochromatic X-rays produced single peak profiles and constant profile shape over a wide 2θ range. A profile fitting with a pseudo-Voigt function was used to determine 2θ angles to 0.0005 deg. for the synchrotron powder data. The peak angle and shape reflected from γ' phases in γ-matrix and those fron electrochemically extracted γ'-phase were significantly different.

scholarly journals Numerical evaluation of the modulus of longitudinal elasticity in structural round timber elements of the Eucalyptus genus

2011 ◽  
Vol 31 (5) ◽  
pp. 1007-1014 ◽  
Author(s):  
André L. Christoforo ◽  
Túlio H. Panzera ◽  
Fabiano B. Batista ◽  
Paulo H. R. Borges ◽  
Francisco A. R. Lahr
Keyword(s):  
Inverse Analysis ◽  
Numerical Evaluation ◽  
Least Square Method ◽  
Least Square ◽  
Analysis Method ◽  
The Finite Element Method ◽  
Eucalyptus Citriodora ◽  
Inverse Analysis Method ◽  
Round Timber

Currently, the standards that deal with the determination of the properties of rigidity and strength for structural round timber elements do not take in consideration in their calculations and mathematical models the influence of the existing irregularities in the geometry of these elements. This study has as objective to determine the effective value of the modulus of longitudinal elasticity for structural round timber pieces of the Eucalyptus citriodora genus by a technique of optimization allied to the Inverse Analysis Method, to the Finite Element Method and the Least Square Method.

scholarly journals Flame Photometric Determination of Alkali Elements in Raw Materials and By-product of Blast Furnace

1956 ◽  
Vol 4 (3) ◽  
pp. 14-22
Author(s):  
Ryohei ISHIDA ◽  
Yoshimasa FUJISHIRO ◽  
Hayata MANAKA ◽  
Yujiro HASHIMOTO ◽  
Hironori KANEKO
Keyword(s):  
Blast Furnace ◽  
Raw Materials ◽  
Photometric Determination ◽  
Alkali Elements

Elimination of Aliquoting in Automated Flame Photometric Determination of K2O in Fertilizers

1984 ◽  
Vol 67 (4) ◽  
pp. 847-850
Author(s):  
Layna D Steele ◽  
Kelly J Ramsey ◽  
Peter F Kane
Keyword(s):  
Full Range ◽  
Flow Analysis ◽  
Photometric Determination ◽  
Photometric Method ◽  
Official Method ◽  
Significant Saving ◽  
Large Numbers ◽  
Continuous Flow Analysis ◽  
Automated Instrument

Abstract Current automated instrument systems used in conjunction with the official AOAC flame photometric method for K2O in fertilizer, 2.D06, all require a dilution step to bring the fertilizer extract to the appropriate concentration range. Two CFA (Continuous Flow Analysis) automated instrument systems are described which together eliminate aliquoting over the full range of fertilizer potassium, a significant saving of analyst effort if large numbers of samples are analyzed. The systems have performance characteristics well within the limits in the official method, and produce results comparable to current methods on routine samples.

scholarly journals Determination of the Sediment Carrying Capacity Based on Perturbed Theory

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Zhi-hui Ni ◽  
Qiang Zeng ◽  
Wu Li-chun
Keyword(s):  
Carrying Capacity ◽  
Influencing Factor ◽  
Least Square Method ◽  
Least Square ◽  
New Method ◽  
Linear Regression Method ◽  
Average Flow Velocity ◽  
New Formula ◽  
Sediment Carrying Capacity

According to the previous studies of sediment carrying capacity, a new method of sediment carrying capacity on perturbed theory was proposed. By taking into account the average water depth, average flow velocity, settling velocity, and other influencing factors and introducing the median grain size as one main influencing factor in deriving the new formula, we established a new sediment carrying capacity formula. The coefficients were determined by the principle of dimensional analysis, multiple linear regression method, and the least square method. After that, the new formula was verified through measuring data of natural rivers and flume tests and comparing the verified results calculated by Cao Formula, Zhang Formula, Li Formula, Engelung-Hansen Formula, Ackers-White Formula, and Yang Formula. According to the compared results, it can be seen that the new method is of high accuracy. It could be a useful reference for the determination of sediment carrying capacity.

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