نتایج جستجو برای: trace element analysis
تعداد نتایج: 3007663 فیلتر نتایج به سال:
Trace elements (TEs) are vital for the operation of metabolic pathways that promote growth and structural integrity. Paddy soils are often prone to TE limitation due to intensive cultivation and irrigation practices. Apart from this, rice paddies are potentially contaminated with transition metals such as Cd, which are often referred to as toxic TEs. Deficiency of TEs in the soil not only delay...
1. Energy, protein, zinc, copper, manganese, selenium and dietary fibre intakes of 100 pre-menopausal women (mean age 30.0 +/- 6.1 years) from a university community, and consuming self-selected diets, were calculated using 3 d dietary records and food composition values. Subjects also collected a 24 h food composite during the 3 d record period for analysis of Zn, Cu and Mn by atomic absorptio...
Overview Inductively coupled plasma-mass spectrometry (ICP-MS) is one of the most powerful techniques used for elemental analysis in environmental applications. It provides the advantage of low detection limits, easy quantification and high throughput. However, experience and best practices are necessary to achieve optimum results. This manuscript focuses on environmental regulations for trace ...
The impact of electron probe microanalysis on the study of geological and planetary materials has been tremendous. Electron microprobes evolved into routine analytical instruments in geological research laboratories as instrument capabilities improved and applications to geologic/planetary materials expanded. The contributions of electron probe microanalysis to the characterization of minerals,...
SOIL ASSOCIATIONS The selenium content of most soils ranges from 0.1 to 2 parts per million. But in general soil selenium content by itself is not a good measure for the potential for occurrence of selenium deficiency in livestock grazing or consuming forages produced from it. Soil pH has a marked effect on the form of selenium present and its availability to the plant. In alkaline, well-aerate...
We investigate the coupling between H, minor, trace, and ultra-trace element incorporations in 17 olivines from ten different locations covering various petrological origins: magmatic, hydrothermal, mantle-derived context. Concentrations major are determined by micro X-ray fluorescence. Minor, elements laser ablation inductively coupled plasma mass spectrometry. Hydrogen concentrations quantifi...
In this paper, we uncover and study a new superconvergence property of a large class of finite element methods for one-dimensional convectiondiffusion problems. This class includes discontinuous Galerkin methods defined in terms of numerical traces, discontinuous Petrov–Galerkin methods and hybridized mixed methods. We prove that the so-called numerical traces of both variables superconverge at...
A nonionic iodinated compound, Nycodenz, was used for density-gradient isolation of platelets before analysis for trace elements by instrumental neutron activation. The platelet samples were almost free from plasma and erythrocytes, and the trace element contribution from additives was insignificant for the elements investigated. The reproducibility of the trace element analysis in platelets at...
determination of trace elements in food is of great importance, as some of them have nutritional significance, whilst others are toxic. long-term exposure to low levels of toxic metals could be important, especially in relation to children. differential pulse anodic stripping voltammetry (dpasv) is applied to simultaneous determination of lead, cadmium, copper and zinc in dry ash infant formula...
Consider the tangential trace of a vector polynomial on the surface of a tetrahedron. We construct an extension operator that extends such a trace function into a polynomial on the tetrahedron. This operator can be continuously extended to the trace space of H(curl ). Furthermore, it satisfies a commutativity property with an extension operator we constructed in Part I of this series. Such exte...
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