scholarly journals Elemental Composition of Norwegian Rivers

1979 ◽  
Vol 10 (2-3) ◽  
pp. 115-140 ◽  
Author(s):  
B. Salbu ◽  
A. C. Pappas ◽  
E. Steinnes
Keyword(s):  
Geometric Mean ◽  
Ore Deposits ◽  
Weighted Mean ◽  
Mean Values ◽  
Marine Deposits ◽  
Water Composition ◽  
Alkaline Earths ◽  
The Individual ◽  
Good Agreement

Instrumental neutron activation analysis has been applied for the determination of up to 40 elements in waters from eleven Norwegian rivers. In order to represent the composition of an average river in the region of Norway and possibly the greater part of the Scandinavian peninsula, weighted mean values are calculated on the basis of geometric mean values and discharge of the individual rivers. Factor analysis shows that Cambro-Silurian sedimentary and vulcanic rocks influence the water composition considerably compared to Precambrian gneisses and granites. An influence of airborne supply is evident in coastal areas. In addition ore deposits are important for Zn and associated elements. Comparison with literature data from Sweden shows good agreement for the elements concerned. The present values concerning alkalies, alkaline earths and halogens are, however, significantly lower than the estimated “world averages”. This is probably due to a low abundance of marine deposits and sedimentary rocks in Scandinavia. Low values are also found for elements which are often associated with particulate matter (Fe, Al, V, Mo, As, Sb, Th, U), while the values obtained for rare earths (La, Ce, Sm) and some additional elements (Sc, Mn, Au) are significantly higher than the estimated “world averages”.

AN INTERCOMPARISON PROJECT ON 14C FROM SINGLE-YEAR TREE RINGS

Radiocarbon ◽  
2021 ◽  
pp. 1-8
Author(s):  
Sabrina G K Kudsk ◽  
Jesper Olsen ◽  
Gregory W L Hodgins ◽  
Mihály Molnár ◽  
Todd E Lange ◽  
...  
Keyword(s):  
Geometric Mean ◽  
Weighted Mean ◽  
University Of Arizona ◽  
General Quality ◽  
Data Points ◽  
Intercomparison Project ◽  
Quality Check ◽  
The Individual ◽  
The University ◽  
Good Agreement

ABSTRACT A laboratory intercomparison project was carried out on 20 annually resolved late-wood samples from the Danish oak record. The project included the following three laboratories: (1) the University of Arizona AMS Laboratory, University of Arizona, USA (AA); (2) HEKAL AMS Laboratory, MTA Atomki, Hungary (DeA); and (3) Aarhus AMS Centre (AARAMS), Aarhus University, Denmark (AAR). The large majority of individual data points (96%) lie within ±2σ of the weighted mean. Further assessment of the accuracy associated with the individual laboratories showed good agreement, indicating that consistent and reliable 14C measurements well in agreement with each other are produced at the three laboratories. However, the quoted analytical uncertainties appear to be underestimated when compared to the observed variance of differences from the geometric mean of the samples. This study provides a general quality check of the single-year tree-ring 14C measurements that are included in the new calibration curve.

scholarly journals On phenomena relating to the spectra of hydrogen and helium

1916 ◽  
Vol 93 (646) ◽  
pp. 27-28
Keyword(s):  
Accurate Determination ◽  
Principal Series ◽  
Black Body ◽  
Black Body Radiation ◽  
Balmer Series ◽  
Mean Values ◽  
Carbon Arc ◽  
The Mean ◽  
The Individual

In a previous paper the structure of broadened spectrum lines was investigated by a method involving the use of a neutral-tinted wedge as an accessory to the spectroscope. The present communication deals with a method for the accurate determination of the photographic intensities of spectrum lines and the reduction of such intensities to absolute values by comparison with the continuous black-body radiation of the carbon arc. These methods have been applied to a study of the relative intensity distribution in the spectra of helium and hydrogen under different conditions of excitation. It has been found that under certain specified conditions there is a transfer of energy from the longer to the shorter wave-lengths in any given series, and that, under such conditions, the associated series, and in particular the Diffuse series, are relatively enhanced at the expense of the Principal series. It has also been found that the distribution of intensity found in certain celestial spectra can be approximately reproduced in the laboratory. In any attempt to interpret the phenomena observed in connection with the Balmer series of hydrogen, it is necessary to know the particular type to which this series belongs. In order to decide this point a study has been made of the separations of the components of lines of the Balmer series of hydrogen, and the mean values of the separations of the doublets constituting the lines H a and H β have been found to be respectively 0.132 Å.U. and 0.033 Å.U. These values are consistent with the separations appropriate to a Principal series, and the first is in precise agreement with the value deduced by Buisson and Fabry. These results have been obtained by crossing a Lummer Gehrcke plate with the neutral wedge, and submitting the contours obtained to mathematical analysis, by means of which the distribution of intensity in the individual components, and the separation of the components, can be determined.

scholarly journals Energy-dispersive spectroscopy for the quantitative determination of the major chemical elements in milk

2021 ◽  
Vol 10 (10) ◽  
pp. e280101018910
Author(s):  
Igor Lima de Paula ◽  
Isis Rodrigues Toledo Renhe ◽  
Rodrigo Stephani ◽  
Ítalo Tuler Perrone ◽  
Antônio Fernandes de Carvalho ◽  
...  
Keyword(s):  
Quantitative Determination ◽  
Chemical Elements ◽  
Raw Milk ◽  
Energy Dispersive ◽  
Mean Values ◽  
Milk Samples ◽  
Application Potential ◽  
Major Chemical ◽  
Good Agreement

The present preliminary study aims at the rapid quantitative determination of the major chemical elements in the ashes of raw milk samples, using energy dispersive X-ray fluorescence spectrometry. The precision of the method was satisfactory (variation coefficient ≤ 5%). The mean values (in mmol·kg-1) obtained from the analysis of 32 raw milk samples showed good agreement with data from the Brazilian and international literature: K (26.1 ± 4.6), Ca (33.8 ± 3.7), P (28.4 ± 2.7), Na (21 ± 3.3) and Mg (4.7 ± 0.5). Residual Cl concentration (19.0 ± 3.3 mmol·kg-1) was lower than expected due to incineration losses. The results suggest a good application potential of the method for other dairy products.

Single Stable Reagent (Arsenazo III) for Optically Robust Measurement of Calcium in Serum and Plasma

1992 ◽  
Vol 38 (6) ◽  
pp. 904-908 ◽  
Author(s):  
N O Leary ◽  
A Pembroke ◽  
P F Duggan
Keyword(s):  
Arsenazo Iii ◽  
External Quality Control ◽  
External Quality ◽  
Mean Values ◽  
Standard Curve ◽  
Control Schemes ◽  
Stable Reagent ◽  
Good Agreement ◽  
Positive Interference

Abstract We describe a method based on a single stable reagent for the determination of calcium in serum and plasma with use of Arsenazo III, 200 mumol/L in 50 mmol/L 1,4-piperazinediethanesulfonic acid (PIPES) buffer. The method showed significant positive interference in plasma at pH less than 6.6 because of the precipitation of fibrinogen, which was eliminated by increasing the pH to 6.8. The assay showed no interference from as much as 600 mumol of bilirubin and 12 g of hemoglobin per liter when applied in a simple monochromatic procedure at 660 nm. The standard curve for calcium was linear from 0 to 5.0 mmol/L. Addition of Intralipid at concentrations greater than 3 g/L demonstrated positive interference, which could be eliminated by using a 700-nm blanking wavelength. The procedure showed good agreement with all-method mean values from two external quality-control schemes.

Determination of Chlorinated Pesticides in Whole Blood

1973 ◽  
Vol 56 (5) ◽  
pp. 1173-1177
Author(s):  
Paula E Stretz ◽  
Henry M Stahr
Keyword(s):  
Sulfuric Acid ◽  
Whole Blood ◽  
Gas Liquid Chromatography ◽  
Chlorinated Pesticides ◽  
Blood Samples ◽  
Mean Values ◽  
Sulfuric Acid Method ◽  
Large Systematic Error ◽  
Good Agreement

Abstract Eight whole blood samples spiked with lindane, dieldrin, and p,p′-DDT at levels of 2.5, 12.6, 126, and 630 ppb each were sent to 11 collaborators for analysis. The method evaluated uses sulfuric acid to liberate the pesticides from the blood matrix. The pesticides are then extracted with 10% acetone in hexane. Pesticides were identified and quantitatively analyzed by gas-liquid chromatography, using an electron capture detector. Mean values at all levels are in good agreement with the spiking levels. However, statistical analysis of the data reveals a large systematic error. Further evaluation of the sulfuric acid method by comparison with other methods is recommended.

Determination of the Degree of Hydrogenation in Hydrogenated Nitrile-Butadiene Rubber (HNBR)

1990 ◽  
Vol 63 (2) ◽  
pp. 244-255 ◽  
Author(s):  
A. J. Marshall ◽  
I. R. Jobe ◽  
T. Dee ◽  
C. Taylor
Keyword(s):  
Standard Procedure ◽  
Analytical Techniques ◽  
Butadiene Rubber ◽  
Preparation Time ◽  
Mean Values ◽  
Wet Chemical ◽  
Absolute Measurements ◽  
Infrared Methods ◽  
Good Agreement

Abstract A number of analytical techniques are available for the measurement of the residual unsaturation in HNBR polymers. However, to insure that high-quality HNBR products are produced, it is necessary to use a standard procedure throughout the industry which is quick, accurate, and precise. The two infrared methods discussed in this paper show good agreement with one another, as shown by the respective mean values in Table V. Thus, in the absence of a totally independent and universally accepted standard procedure, this crosscheck between two separate and absolute measurements for the degree of hydrogenation is the best possible support for their precision (1H-NMR spectroscopy for IR method #1 and IR spectroscopy for IR method #2). The two iodometric methods each exhibit significantly poorer precision ( 10 to 100 times) than either of the infrared methods. This is not surprising, since these wet chemical techniques are not discriminatory to any type of unsaturation present in the HNBR nor are they inherently precise due to the large number of test variables. This lack of precision, and the fact that these wet chemical methods are time consuming, eliminates them from consideration as quality-oriented testing methods for measuring the degree of hydrogenation in HNBR. Both IR methods exhibit good reproducibility which greatly exceeds that of iodometry. The statistical analysis of these IR techniques does not present any significant differences between them. IR method #1 requires virtually no preparation time, since extraction of the HNBR rubber samples is not required. Furthermore, IR method #1 is less susceptible to impurities and subsequent user interpretation, since the hydrogenated butadiene peaks at 723 cm−1 are not required for the analysis. In conclusion, due to simplicity and speed of the analysis, IR method #1 is much more robust for use by the industry and their customers for the measurement of carbon-carbon double-bond unsaturation in HNBR.

scholarly journals Automatic Determination of Secondary Dendrite Arm Spacing in AlSi-Cast Microstructures

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2827
Author(s):  
Christian Gawert ◽  
Rüdiger Bähr
Keyword(s):  
Computation Time ◽  
Automatic Measurement ◽  
Secondary Dendrite Arm Spacing ◽  
Dendrite Arm Spacing ◽  
Aluminum Cast Alloys ◽  
Cast Alloys ◽  
The Individual ◽  
Good Agreement

A new procedure for the automatic measurement of the secondary dendrite arm spacing (SDAS) from microscopic images is presented. The individual primary and secondary dendrite arms are identified through suitable segmentation techniques and clustered in such a way that dendritic structures are obtained suitable for SDAS measurement. The algorithms are applied to two different hypoeutectic aluminum cast alloys, and the quality of the measurements obtained is assessed through a comparison to manually measured SDAS values. A good agreement between the automated measurements and the distribution of manual measurements is found for both cast structures considered. In addition, a decrease in computation time is observed which allows for an increase in measurement density that is used to characterize the microstructures.

scholarly journals Improved Signals Ratio Resolution Method by Optimization of Resolution Function—Simultaneous Determination of Cu(II) and Cd(II) in Water Samples

1999 ◽  
Vol 82 (5) ◽  
pp. 1185-1197
Author(s):  
Zorana Grabarić ◽  
Damir Iveković ◽  
Laszlo Sipos ◽  
Bozidar S Grabarić
Keyword(s):  
Metal Ions ◽  
Simultaneous Determination ◽  
Point Of View ◽  
Ratio Method ◽  
Resolution Method ◽  
Mean Values ◽  
The Difference ◽  
The Individual ◽  
Fold Excess

Abstract From an ecological and economical point of view, it is important to design analytical procedures for monitoring heavy metals in the environment and industrial processes in a way to minimize the use of hazardous reagents and reduce the analysis time. In this paper, a well-known dithizonate extraction-based method for the determination of many metal ions was improved by using chemometrical selectivity of the strongly overlapped spectra of copper and cadmium dithizonates in CCl4 for their simultaneous determination from a single extraction at pH 10. The individual absorption spectra, having absorption maxima difference of only 20 nm, were separated, and the metal ions were quantified by using an improved procedure for optimizing the resolving function in a recently proposed signals ratio method. The procedure consists of using many different resolving functions and plotting the difference of the mean of absolute and nonabsolute mean values of pseudosignals [PDMMV (PS)] against analyte concentrations obtained with each of the resolving functions, thus obtaining 2 straight lines having intersections that give a unique and reliable value of the unknown concentration of the individual analyte in mixture giving strongly overlapped spectra. In this way, the main drawback of the signals ratio resolution method, that is, the visual estimation of optimal resolving function, is eliminated. The proposed parameter, PDMMV (PS), was tested by using both simulated and experimental spectra. Copper was determined in the mixture with ca 20-fold excess of cadmium, and cadmium was determined in ca 10-fold excess of copper at submicromolar concentration levels.

scholarly journals Studies on magnesium in ruminant nutrition

1967 ◽  
Vol 21 (3) ◽  
pp. 631-642 ◽  
Author(s):  
A. C. Field
Keyword(s):  
Dry Matter ◽  
Urine Volume ◽  
Regression Coefficients ◽  
Sheep Grazing ◽  
Mean Values ◽  
The Mean ◽  
The Difference ◽  
The Individual ◽  
Total Excretion ◽  
Good Agreement

1. The excretions of magnesium, calcium, potassium and faecal dry matter (DM) by sheep grazing the same pasture have been determined at intervals throughout two grazing seasons. Two groups of four wethers, 2 and 7 years old, were used. Collections of faeces were total and of urine only partial; creatinine was used as an indicator of urine volume.2.The overall mean outputs of DM in the faeces of the young and old sheep were 509 and 387 g/day respectively.3. The values for the percentage digestibility of herbage DM ranges from 81.1 in spring to 63.2 in winter. The overall means for the estimated intake of DM by the young and old sheep were 1859 and 1405 g/day respectively and the difference was highly significant (P < 0.001).4. The mean values for overall excretion of Mg by the young and old sheep were respectively 0.452 and 0.292 g/day in the urine and 2.70 and 2.21 g/day in the faeces. For all sheep there was a highly significant rectilinear relationship between the amount in urine and in faeces, but there were significant differences between the regression coefficients for the individual sheep.5. The values for the excretion of Ca in urine and faeces were significantly higher for the young than for the old sheep; the respective means were 0.385 and 0.306 g/day for urinary Ca and 13.02 and 10.8 g/day for faecal Ca.6.The mean values for the excretion of K by the young and old sheep were respectively 28.2 and 29.1 g/day in the urine and 7.1 and 3.9 g/day in the faeces, the latter differences being highly significant.7.High values for the total excretion of Mg, Ca and K occurred in June and low values in winter.8. Intakes of Mg, Ca and K by the sheep have been calculated from the information on intake of DM and chemical composition of the cut herbage and compared with total excretion in urine and faeces. Good agreement between the two sets of values was obtained for Mg, but not for either Ca or K. The possible causes of these findings have been discussed and it was concluded that the sheep selected herbage with concentrations of Ca and K different from those in the samples of cut herbage.

scholarly journals Determination of the Backfilling Time for the Zinc and Lead Ore Deposits with Application of the BackfillCAD Model

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3186
Author(s):  
Krzysztof Skrzypkowski
Keyword(s):  
Cross Sections ◽  
Computer Aided Design ◽  
Laboratory Tests ◽  
Volume Ratio ◽  
Ore Deposits ◽  
Geometrical Parameters ◽  
The Individual ◽  
Aided Design ◽  
Relationship Of

This article introduces a BackfillCAD model that relates to the determination of the backfilling time. The relationship of the individual model modules using a flow chart are characterized and presented. The main aim of the research was to determine the time of backfilling for the prospective deposits of zinc and lead ores in the Olkusz region in Poland. In the first stage of the research, laboratory tests were carried out on the backfilling mixture consisting of sand and water in a 1:1 volume ratio. In the laboratory tests, the content of grains below 0.1 mm, the washability, water permeability, and compressibility of the backfilling mixture were determined. After the standard requirements were met by the backfilling mixture, the arrangement of one-way and bidirectional strip excavations was designed. In the next stages, by means of computer aided-design MineScape software, maximum thicknesses of the ore-bearing dolomite layer (T21_VI) for four geological cross-sections were determined. The height of the first backfilled layer with a thickness of 5 m was analyzed. Taking into account the geometrical parameters of the strip—the maximum length and its width and height, as well as the capacity of the backfilling installation—this study calculated the backfilling times for the future strip excavations.

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