Chemical metrology, chemistry and the uncertainty of chemical measurements

2002 ◽  
Vol 7 (3) ◽  
pp. 95-100 ◽  
Author(s):  
John L. Love
Keyword(s):  
Chemical Metrology ◽  
Chemical Measurements

Incorporation of spatial variability in modeling non-point source groundwater nitrate pollution

1996 ◽  
Vol 33 (4-5) ◽  
pp. 233-240 ◽  
Author(s):  
F. S. Goderya ◽  
M. F. Dahab ◽  
W. E. Woldt ◽  
I. Bogardi
Keyword(s):  
Spatial Variability ◽  
Point Source ◽  
Three Dimensional ◽  
Nitrate Contamination ◽  
Geostatistical Simulation ◽  
Chemical Measurements ◽  
Spatially Distributed ◽  
Potential Benefits ◽  
Zone Modeling ◽  
Physical And Chemical

A methodology for incorporation of spatial variability in modeling non-point source groundwater nitrate contamination is presented. The methodology combines geostatistical simulation and unsaturated zone modeling for estimating the amount of nitrate loading to groundwater. Three dimensional soil nitrogen variability and 2-dimensional crop yield variability are used in quantifying potential benefits of spatially distributed nitrogen input. This technique, in combination with physical and chemical measurements, is utilized as a means of illustrating how the spatial statistical properties of nitrate leaching can be obtained for different scenarios of fixed and variable rate nitrogen applications.

scholarly journals Direct Chemical Measurement of the λ of the Lumped Constant of the [14C]Deoxyglucose Method in Rat Brain: Effects of Arterial Plasma Glucose Level on the Distribution Spaces of [14C]Deoxyglucose and Glucose and on λ

1989 ◽  
Vol 9 (3) ◽  
pp. 304-314 ◽  
Author(s):  
Kentaro Mori ◽  
Nancy Cruz ◽  
Gerald Dienel ◽  
Thomas Nelson ◽  
Louis Sokoloff
Keyword(s):  
Plasma Glucose ◽  
Glucose Concentration ◽  
Severe Hypoglycemia ◽  
Plasma Glucose Concentration ◽  
Operational Equation ◽  
Chemical Measurements ◽  
Lumped Constant ◽  
Dg Method ◽  
Arterial Plasma ◽  
Distribution Spaces

The lumped constant in the operational equation of the 2-[14C]deoxyglucose (DG) method contains the factor λ that represents the ratio of the steady-state tissue distribution spaces for [14C]DG and glucose. The lumped constant has been shown to vary with arterial plasma glucose concentration. Predictions based mainly on theoretical grounds have suggested that disproportionate changes in the distribution spaces for [14C]DG and glucose and in the value of λ are responsible for these variations in the lumped constant. The influence of arterial plasma glucose concentration on the distribution spaces for DG and glucose and on λ were, therefore, determined in the present studies by direct chemical measurements. The brain was maintained in steady states of delivery and metabolism of DG and glucose by programmed intravenous infusions of both hexoses designed to produce and maintain constant arterial concentrations. Hexose concentrations were assayed in acid extracts of arterial plasma and freeze-blown brain. Graded hyperglycemia up to 28 m M produced progressive decreases in the distribution spaces of both hexoses from their normoglycemic values (e.g., ∼ – 20% for glucose and – 50% for DG at 28 m M). In contrast, graded hypoglycemia progressively reduced the distribution space for glucose and increased the space for [14C]DG. The values for λ were comparatively stable in normoglycemic and hyperglycemic conditions but rose sharply (e.g., as much as 9–10-fold at 2 m M) in severe hypoglycemia.

scholarly journals Complementary Use of Magnetometric Measurements for Geochemical Investigation of Light REE Concentration in Anthropogenically Polluted Soils

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 457
Author(s):  
Piotr Fabijańczyk ◽  
Jarosław Zawadzki
Keyword(s):  
Soil Samples ◽  
Soil Conditions ◽  
Soil Cores ◽  
Light Rare Earth ◽  
Polluted Soils ◽  
Chemical Measurements ◽  
Geochemical Investigation ◽  
Light Rare Earth Elements ◽  
Soil Magnetic Susceptibility ◽  
Geophysical Measurements

The purpose of this study was to use fast geophysical measurements of soil magnetic susceptibility (κ) as supplementary data for chemical measurements of selected light rare earth elements (REEs) in soil. In order to ensure diversity in soil conditions, anthropogenic conditions and types of land use, seven areas were selected, all located in regions subjected to past or present industrial pollution. Magnetometric parameters were measured using a selected magnetic sensor that was specially designed for measurements of soil cores and were used to classify collected soil cores into six distinctive types. The analysis of REEs concentrations in soil was carried out taking into account the grouping of collected soil samples based on the type of study area (open, forested and mountain), and additionally on the measured magnetometric parameters of collected soil cores. A use of magnetometric measurements provided different, but complementary to chemical measurements information, which allowed to obtain deeper insight on REEs concentrations in soils in studied areas.

Roles of chemical metrology in electronics industry and associated environment in Korea: A tutorial

Talanta ◽  
2015 ◽  
Vol 134 ◽  
pp. 284-291 ◽  
Author(s):  
Namgoo Kang ◽  
Kyung Joong Kim ◽  
Jin Seog Kim ◽  
Joung Hae Lee
Keyword(s):  
Electronics Industry ◽  
Chemical Metrology

Preparation of Immobilized Chromium Schiff Base Complexes and their Catalytic Performance for Olefins Epoxidation

2014 ◽  
Vol 692 ◽  
pp. 240-244
Author(s):  
Gong De Wu ◽  
Xiao Li Wang ◽  
Zhi Li Zhai
Keyword(s):  
Hydrogen Peroxide ◽  
Schiff Base ◽  
Elemental Analysis ◽  
Catalytic Performance ◽  
Schiff Base Complexes ◽  
Metal Centers ◽  
Chemical Measurements ◽  
Physico Chemical ◽  
Immobilized Complexes ◽  
Mcm 41

A series of transition metal alanine-salicylaldehyde Schiff base chromium (III) complexes immobilized on MCM-41 were prepared and characterized by various physico-chemical measurements such as FIIR, XRD, HRTEM, N2 sorption and elemental analysis. The immobilized complexes were effective and stable catalysts for the epoxidation of styrene and cyclohexene with 30% hydrogen peroxide. Moreover, the metal centers were found to play important roles in the catalytic performance of immobilized complex catalysts.

Potential Fallacy of Correlating Hedonic Responses with Physical and Chemical Measurements

1981 ◽  
Vol 46 (2) ◽  
pp. 583-588 ◽  
Author(s):  
AILEEN SONTAG TRANT ◽  
ROSE MARIE PANGBORN ◽  
ANGELA C. LITTLE
Keyword(s):  
Chemical Measurements ◽  
Physical And Chemical
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