Relationship between the representative element volume and discontinuity parameters

2020 ◽  
Vol 54 (1) ◽  
pp. qjegh2019-071
Author(s):  
Shengyuan Song ◽  
Qiang Xu ◽  
Jianping Chen ◽  
Fengyan Wang ◽  
Ying Liu ◽  
...  
Keyword(s):  
Fracture Network ◽  
Volume Density ◽  
Empirical Formulas ◽  
Representative Element ◽  
Linear Relationships ◽  
Discontinuity Orientation ◽  
Homogeneous Domains ◽  
Representative Element Volume ◽  
The Relationship ◽  
Dfn Model

We introduce an application of the discrete fracture network (DFN) model and 3D persistence to study the relationship between the representative element volume (REV) size and discontinuity information. To avoid the influence of heterogeneity on the distribution of discontinuities, the dam abutment rock mass of the Songta hydropower station is divided into eight statistically homogeneous domains based on the discontinuity orientation and trace length. An optimum DFN model is established for each homogeneous domain. Cubes of different sizes are extracted from the centre of the corresponding DFN model. Based on the discontinuity projection method, the 3D persistence values within the DFN model and each cube are calculated separately. The relative error of persistence for each cube and the DFN model are used to evaluate the size effect and to identify the REV size. Subsequently, the relationship between the determined REV size and the corresponding discontinuity information is systematically researched. Our results show that the discontinuity diameter, the volume density and the Fisher constant have separate linear relationships with the REV size. We present the empirical formulas for estimating the REV size according to the discontinuity diameter, the volume density and the Fisher constant.

scholarly journals A methodology of re-generating a representative element volume of fractured rock mass

2020 ◽  
Vol 71 (4) ◽  
pp. 347-358
Author(s):  
DANG Hong-Lam ◽  
THINH Phi Hong
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Fracture Network ◽  
Hydraulic Calculation ◽  
Fractured Rock Mass ◽  
Fracture Characteristics ◽  
Mechanical Calculation ◽  
Representative Element ◽  
Representative Element Volume ◽  
Actual Fracture

In simulation of fractured rock mass such as mechanical calculation, hydraulic calculation or coupled hydro-mechanical calculation, the representative element volume of fractured rock mass in the simulating code is very important and give the success of simulation works. The difficulties of how to make a representative element volume are come from the numerous fractures distributed in different orientation, length, location of the actual fracture network. Based on study of fracture characteristics of some fractured sites in the world, the paper presented some main items concerning to the fracture properties. A methodology of re-generating a representative element volume of fractured rock mass by DEAL.II code was presented in this paper. Finally, some applications were introduced to highlight the performance as well as efficiency of this methodology.

scholarly journals Lack of an association between gallstone disease and bilirubin levels with risk of colorectal cancer: a Mendelian randomisation analysis

2021 ◽  
Author(s):  
Richard Culliford ◽  
Alex J. Cornish ◽  
Philip J. Law ◽  
Susan M. Farrington ◽  
Kimmo Palin ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Large Scale ◽  
Causal Effect ◽  
Gallstone Disease ◽  
Epidemiological Studies ◽  
Mendelian Randomisation ◽  
Linear Relationships ◽  
Potential Risk Factors ◽  
The Relationship ◽  
Circulating Levels

Abstract Background Epidemiological studies of the relationship between gallstone disease and circulating levels of bilirubin with risk of developing colorectal cancer (CRC) have been inconsistent. To address possible confounding and reverse causation, we examine the relationship between these potential risk factors and CRC using Mendelian randomisation (MR). Methods We used two-sample MR to examine the relationship between genetic liability to gallstone disease and circulating levels of bilirubin with CRC in 26,397 patients and 41,481 controls. We calculated the odds ratio per genetically predicted SD unit increase in log bilirubin levels (ORSD) for CRC and tested for a non-zero causal effect of gallstones on CRC. Sensitivity analysis was applied to identify violations of estimator assumptions. Results No association between either gallstone disease (P value = 0.60) or circulating levels of bilirubin (ORSD = 1.00, 95% confidence interval (CI) = 0.96–1.03, P value = 0.90) with CRC was shown. Conclusions Despite the large scale of this study, we found no evidence for a causal relationship between either circulating levels of bilirubin or gallstone disease with risk of developing CRC. While the magnitude of effect suggested by some observational studies can confidently be excluded, we cannot exclude the possibility of smaller effect sizes and non-linear relationships.

scholarly journals Differential Influence of Age on the Relationship between Genetic Mismatch and A(H1N1)pdm09 Vaccine Effectiveness

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 619
Author(s):  
Lirong Cao ◽  
Shi Zhao ◽  
Jingzhi Lou ◽  
Hong Zheng ◽  
Renee W. Y. Chan ◽  
...  
Keyword(s):  
Age Groups ◽  
The Elderly ◽  
Vaccine Effectiveness ◽  
Amino Acid Mutation ◽  
Epidemic Season ◽  
Vaccine Component ◽  
Linear Relationships ◽  
The Difference ◽  
Middle Aged Adults ◽  
The Relationship

Assessment of influenza vaccine effectiveness (VE) and identification of relevant influencing factors are the current priorities for optimizing vaccines to reduce the impacts of influenza. To date, how the difference between epidemic strains and vaccine strains at genetic scale affects age-specific vaccine performance remains ambiguous. This study investigated the association between genetic mismatch on hemagglutinin and neuraminidase genes and A(H1N1)pdm09 VE in different age groups with a novel computational approach. We found significant linear relationships between VE and genetic mismatch in children, young adults, and middle-aged adults. In the children’s group, each 3-key amino acid mutation was associated with an average of 10% decrease in vaccine effectiveness in a given epidemic season, and genetic mismatch exerted no influence on VE for the elderly group. We demonstrated that present vaccines were most effective for children, while protection for the elderly was reduced and indifferent to vaccine component updates. Modeling such relationships is practical to inform timely evaluation of VE in different groups of populations during mass vaccination and may inform age-specific vaccination regimens.

A Fluidity-Temperature Relationship for Liquids

1973 ◽  
Vol 95 (2) ◽  
pp. 236-241
Author(s):  
T. F. Ford ◽  
C. R. Singleterry
Keyword(s):  
Interpolation Formula ◽  
Absolute Temperature ◽  
Temperature Relationship ◽  
Organic Liquids ◽  
Low Viscosity ◽  
Linear Relationships ◽  
Temperature Ranges ◽  
The Absolute ◽  
The Relationship

Many relationships between viscosity or its reciprocal, fluidity, and temperature have been proposed for liquids. None except the empirically modified ASTM chart have proven satisfactory over extended temperature ranges. We here note that by plotting the kinematic fluidity (φkin) against the square of the absolute temperature (deg K2) we obtain linear relationships for a wide variety of organic liquids at kinematic viscosities less than about 1.67 centistokes (or fluidities above about 0.60 reciprocal centistokes). The generality of the relationship appears to justify the use of the equation, φkin=a+bT2, as an interpolation formula for organic liquids in the low viscosity region.

scholarly journals FINANCIAL VALUE OF UKRAINIAN PREMIER LEAGUE CLUBS IN RELATIONSHIP WITH FOOTBALL MIGRATION INDICATORS

2021 ◽  
Vol 6 (2) ◽  
pp. 184-195
Author(s):  
Sobol Eduard ◽  
Svatyev Andrii
Keyword(s):  
Football Players ◽  
Professional Football ◽  
Premier League ◽  
Linear Relationships ◽  
Football Clubs ◽  
Economic Support ◽  
And Migration ◽  
Quantitative Indicators ◽  
The Relationship ◽  
Generalization Of Data

Introduction. Indicators of financial and economic support and migration of football players create preconditions for the formation of a highly competitive sports environment in professional football clubs and in the Ukrainian Premier League. The aim of the study is to analyze the quantitative indicators of migration of football players in the Ukrainian Premier League in relation to the financial and economic support of professional football clubs and to systematize the results. Materials and methods: analysis and generalization of data of scientific and methodical literature sources and the Internet, pedagogical observations, content analysis of materials of official sites of professional football clubs of the Ukrainian Premier League, official sites of the Ukrainian Football Association and the Ukrainian Premier League, methods of mathematical statistics. Results. The relationship between the financial value of Ukrainian athletes and migrant footballers, who are declared in the competition of the Ukrainian Premier League of the season 2021-2022, is analyzed. Conclusions. Analysis of the financial value of professional football clubs of the Ukrainian Premier League in relation to the migration of football players allows us to state that the leaders of the sports rating are the most financially capable teams: «Shakhtar» (Donetsk) and «Dynamo» (Kyiv), with a total the transfer value of the players is € 179,700,000 and € 136,100,000 respectively. The average cost of a migrant player in the leading professional football clubs of the Ukrainian Premier League «Shakhtar» (Donetsk) is 8,800,000 €, «Dynamo» (Kyiv) ‒ 3,420,000 €. Analysis of the transfer value of domestic athletes and migrant footballers in the application letters of the Ukrainian Premier League shows the absence of direct and inverse linear relationships, which suggests the presence of complex multilevel dependencies that require processing by more complex mathematical and statistical methods and preliminary grouping of available experimental data

scholarly journals Temperature-Driven Hydrocarbon Generation-Expulsion and Structural Transformation of Organic-Rich Shale Assessed by in situ Heating SEM

2021 ◽  
Vol 9 ◽  
Author(s):  
Yuan Yuan ◽  
Jijin Yang
Keyword(s):  
Structural Changes ◽  
Fracture Network ◽  
Reservoir Rock ◽  
Continuous Heating ◽  
Hydrocarbon Generation ◽  
Sem Images ◽  
Cap Rock ◽  
Hydrocarbon Expulsion ◽  
The Relationship

Mud shale can serve as source or cap rock but also as a reservoir rock, and so the development of pores or cracks in shale has become of great interest in recent years. However, prior work using non-identical samples, varying fields of view and non-continuous heating processes has produced varying data. The unique hydrocarbon generation and expulsion characteristics of shale as a source rock and the relationship with the evolution of pores or cracks in the reservoir are thus not well understood. The present work attempted to monitor detailed structural changes during the continuous heating of shale and to establish possible relationships with hydrocarbon generation and expulsion by heating immature shale samples while performing in situ scanning electron microscopy (SEM) imaging and monitoring the chamber vacuum. Samples were heated at 20°C/min from ambient to 700°C with 30 min holds at 100°C intervals during which SEM images were acquired. The SEM chamber vacuum was found to change during sample heating as a consequence of hydrocarbon generation and expulsion. Two episodic hydrocarbon expulsion stages were observed, at 300 and 500°C. As the temperature was increased from ambient to 700°C, samples exhibited consecutive shrinkage, expansion and shrinkage, and the amount of structural change in the vertical bedding direction was greater than that in the bedding direction. At the same time, the opening, closing and subsequent reopening of microcracks was observed. Hydrocarbon generation and expulsion led to the expansion of existing fractures and the opening of new cracks to produce an effective fracture network allowing fluid migration. The combination of high-resolution SEM and a high-temperature heating stage allowed correlation between the evolution of pores or cracks and hydrocarbon generation and expulsion to be examined.

scholarly journals NON-LINEAR RELATIONSHIPS BETWEEN HOUSE SIZE AND PRICE

2021 ◽  
Vol 25 (3) ◽  
pp. 240-253
Author(s):  
Shih-Tao Feng ◽  
Chien-Wen Peng ◽  
Chung-Hsien Yang ◽  
Pei-Wen Chen
Keyword(s):  
Housing Affordability ◽  
Housing Unit ◽  
Size Premium ◽  
Quantile Regression Model ◽  
Linear Relationships ◽  
The Relationship ◽  
Marginal Price ◽  
Special Zone ◽  
Total Price ◽  
House Size

This study reexamines the relationship between house size and price by using the quantile regression model. Housing transactions data of the National Taipei University Special Zone in Taiwan are adopted, and the findings are as follows. First, the total price of a smaller housing unit will increase at a decreasing rate as its size increases. The decrease in marginal price might be due to the declining marginal utility of the property right. Secondly, the total price of a larger housing unit will increase at an increasing rate as its size increases. The size premium effect might be due to the influence of conspicuous consumption. Thirdly, housing with a lower square meter price is subject to greater price competitiveness in the market, and the price will increase at a decreasing rate as the size increases. Conversely, a housing unit with a higher square meter price will decrease at an increasing rate as its size increases. This might be due to the constraint imposed by the purchaser’s housing affordability. These findings clarify the nonlinear relationships between housing size and price, and provide very useful information for decision making of the developers, home purchasers, real estate appraisers, and the governments.

Relationship between the Differences of Odor Detection Threshold Values Measured by Different Methods and some of the Physicochemical Properties

2013 ◽  
Vol 807-809 ◽  
pp. 451-455 ◽  
Author(s):  
Di Fang ◽  
Jie Min Liu ◽  
Qin Yi
Keyword(s):  
Physicochemical Properties ◽  
Functional Group ◽  
Saturated Vapor ◽  
Detection Threshold ◽  
Threshold Values ◽  
Odor Detection ◽  
Linear Relationships ◽  
Odor Detection Threshold ◽  
The Difference ◽  
The Relationship

The amount of sample can enter the nasal cavity depends on the physiochemical characteristics such as distribution, volatility and solubility. It can be suspected that the difference of odor detection threshold (ODT) measured by different methods is related to the physicochemical properties of compounds. To investigate the relationship between ODT differences and the physicochemical properties of compounds, ODT values of four series of organic compounds were measured by triangle odor bag method and gas chromatography and olfactometry method; the results were compared and the absolute differences were calculated. Relationship between ODT differences and the type of functional group and some of the physicochemical properties of compounds was analyzed. The results showed the type of functional group had significant effect on the differences. Certain linear relationships between the logarithmic value of differences and the logarithmic values of saturated vapor pressure and molecular weight were observed.

Measurement error-filtered machine learning in digital soil mapping

2021 ◽  
Author(s):  
Stephan van der Westhuizen ◽  
Gerard Heuvelink ◽  
David Hofmeyr
Keyword(s):  
Machine Learning ◽  
Measurement Error ◽  
Soil Property ◽  
Soil Mapping ◽  
Digital Soil Mapping ◽  
Simulation Studies ◽  
True Value ◽  
Linear Relationships ◽  
The Difference ◽  
The Relationship

<p>Digital soil mapping (DSM) may be defined as the use of a statistical model to quantify the relationship between a certain observed soil property at various geographic locations, and a collection of environmental covariates, and then using this relationship to predict the soil property at locations where the property was not measured. It is also important to quantify the uncertainty with regards to prediction of these soil maps. An important source of uncertainty in DSM is measurement error which is considered as the difference between a measured and true value of a soil property.</p><p>The use of machine learning (ML) models such as random forests (RF) has become a popular trend in DSM. This is because ML models tend to be capable of accommodating highly non-linear relationships between the soil property and covariates. However, it is not clear how to incorporate measurement error into ML models. In this presentation we will discuss how to incorporate measurement error into some popular ML models, starting with incorporating weights into the objective function of ML models that implicitly assume a Gaussian error. We will discuss the effect that these modifications have on prediction accuracy, with reference to simulation studies.</p>

Sign in / Sign up

Export Citation Format

Share Document