Definition and Analysis of Natural and Anthropogenic Geochemical Вackground for the Boss-Biomonitoring Method

A study was conducted on the content of chemical elements in the epiphytic moss of Pylaisia polyantha (Hedw.) V.S.G. The moss samples were taken from 6 background areas of the West Siberian region, as well as in the city of Tomsk. The content of chemical elements is determined using neutron activation analysis. The hypothesis about the normal/log-normal distribution of the concentrations of chemical elements was tested using the χ2 criterion; asymmetry and kurtosis were used for samples less than 20. When the hypothesis is confirmed, the background concentrations of chemical elements are defined as mean values ±2σ. The concentrations of each background area are subject to the normal distribution law. For the overwhelming number of elements, the anthropogenic background of the city of Tomsk is 2 times or more natural.

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The Application of Bounded Normal Distribution in Statistics of Concrete Strength

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.671-674.1641 ◽

2013 ◽

Vol 671-674 ◽

pp. 1641-1647

Author(s):

Xu Yan ◽

Yong Zhi Zuo ◽

Qiao Zhi Lu ◽

Da Huo ◽

Ming Liu

Keyword(s):

Compressive Strength ◽

Normal Distribution ◽

Goodness Of Fit ◽

Concrete Strength ◽

Concrete Compressive Strength ◽

Mean Values ◽

Coefficients Of Variations ◽

Log Normal ◽

Original Strength ◽

Log Normal Distribution

23,037 values of concrete compressive strength from construction sites were obtained from Beijing Building Construction Research Institute from 2009-2012 by standard cubes testing method. The mean values, standard deviations, coefficients of variations, maxima and minima were derived from the original strength values analyzed and compared with the data in 1989. The results make up for the lack in C25/C30 and the maxima/minima of every strength class of concrete of the former data. Both the coefficients of variations and mean values have increased in recent years. The log-normal distribution commonly used in concrete compressive strength statistics is not that suitable for strength modeling for it is unbounded. So a bounded normal distribution was given in this paper. By Geary's test, the goodness-of-fit of bounded normal distribution is better than log-normal distribution has been proved.

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A Universal Model for the Log-Normal Distribution of Elasticity in Polymeric Gels and Its Relevance to Mechanical Signature of Biological Tissues

Biology ◽

10.3390/biology10010064 ◽

2021 ◽

Vol 10 (1) ◽

pp. 64

Author(s):

Arnaud Millet

Keyword(s):

Elastic Modulus ◽

Normal Distribution ◽

Biological Tissues ◽

Force Microscopy ◽

Polymeric Gels ◽

Atomic Force ◽

Clear Explanation ◽

Log Normal ◽

Log Normal Distribution

The mechanosensitivity of cells has recently been identified as a process that could greatly influence a cell’s fate. To understand the interaction between cells and their surrounding extracellular matrix, the characterization of the mechanical properties of natural polymeric gels is needed. Atomic force microscopy (AFM) is one of the leading tools used to characterize mechanically biological tissues. It appears that the elasticity (elastic modulus) values obtained by AFM presents a log-normal distribution. Despite its ubiquity, the log-normal distribution concerning the elastic modulus of biological tissues does not have a clear explanation. In this paper, we propose a physical mechanism based on the weak universality of critical exponents in the percolation process leading to gelation. Following this, we discuss the relevance of this model for mechanical signatures of biological tissues.

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