Slake Durability Index of the Stone Aggregate Used in the Morelia Michoacán Region

2020 ◽  
Vol 862 ◽  
pp. 61-65
Author(s):  
Marco Antonio Navarrete Seras ◽  
Francisco Javier Domínguez Mota ◽  
Elia Mercedes Alonso-Guzmán ◽  
Wilfrido Martínez-Molina ◽  
Hugo Luis Chavez-Garcia ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Logistic Regression ◽  
The Other ◽  
Absorption Data ◽  
Slake Durability Index ◽  
Slake Durability ◽  
Mexican State ◽  
Durability Index ◽  
Materials Used ◽  
The Relationship

The study of durability is very important because buildings are expected to last; since durability is attributed to the materials used in construction, the study of such materials is required. Among them, stones play a fundamental role as part of the structures, as well as stone aggregates in the elaboration of asphalt blends and concrete blends. Bearing this facts in mind, quarry stones of volcanic and crushed materials were studied in the mexican state of Michoacán.In this work, the Id2, density, and absorption data were correlated to obtain a mathematical model that helps predict Id2 and verify the relationship between the variables. On the other hand, logistic regression was used to classify rock quarries according to their durability index.

Effects of Laumontite Hydration/Dehydration on Swelling Deformation and Slake Durability of Altered Granodiorite

2020 ◽  
Vol 26 (4) ◽  
pp. 507-516
Author(s):  
Junsong Yan ◽  
Junhui Shen ◽  
Kaizhen Zhang ◽  
Jianjun Xu ◽  
Weifeng Duan ◽  
...  
Keyword(s):  
Axial Strain ◽  
Test Results ◽  
X Ray Diffraction ◽  
Dam Foundation ◽  
Hydro Power ◽  
Slake Durability Index ◽  
Slake Durability ◽  
Dehydration Reactions ◽  
Short Period ◽  
Durability Index

ABSTRACT The mineral laumontite can undergo hydration/dehydration reactions at room temperature. The hydration/dehydration produces a 3 to 6 percent volume change in the unit cell. The effects of laumontite hydration/dehydration on swelling and slake durability were investigated using altered granodiorite containing laumontite from the dam foundation of Yangfanggou Hydro Power Station, Sichuan, China. The occurrence of laumontite in altered rocks was first determined by petrological analysis. Typical samples were then collected for laboratory X-ray diffraction (XRD) analyses, free swelling tests, and slake durability index (SDI) tests. The test results were analyzed to determine the quantitative relationships between laumontite content, maximum axial strain, and slake durability index. We found that hydration of laumontite led to rock swelling. As laumontite content increased, maximum axial strain increased linearly; if water penetrated the rock quickly, swelling occurred over a short period. The hydration/dehydration of laumontite decreased slake durability of the rock; the SDI decreased approximately linearly as laumontite content increased.

scholarly journals Improved Mathematical Model of Polluted Insulators nonlinear behaviour Under AC Voltage Based on Experimental Tests

2018 ◽  
Author(s):  
MousalrezaFaramarzi Palangar ◽  
Mohammad Mirzaie
Keyword(s):  
Thermal Conductivity ◽  
Mathematical Model ◽  
Mathematical Models ◽  
Experimental Tests ◽  
The Other ◽  
Critical Voltage ◽  
Nonlinear Behaviour ◽  
New Model ◽  
The Relationship ◽  
Good Agreement

Abstract—In this paper, an improved mathematical model for flashover behavior of polluted insulators is proposed based on experimental tests. In order to determine the flashover model of polluted insulators, the relationship between conductivity and salinity of solution pollution layer of the insulator is measured. Then, the leakage of current amplitude of four common insulators versus axial, thermal conductivity and arc constants temperature was determined. The experimental tests show that top leakage distance (TLd) to bottom leakage distance (BLd) ratio of insulators has a significant effect on critical voltage and current. Therefore, critical voltage and current were modeled by TLd to BLd ratio Index (M). Also, salinity of solution pollution layer of the insulators has been applied to this model by resistance pollution parameter. On the other hand, arc constants of each insulator in new model have been identified based on experimental results. Finally, a mathematical model is intended for critical voltage against salinity of solution pollution layer of different insulators. This model depends on insulator profile. There is a good agreement between the experimental tests of pollution insulators obtained in the laboratory and values calculated from the mathematical models developed in the present study.

scholarly journals Improved Mathematical Model of Polluted Insulators nonlinear behaviour Under AC Voltage Based on Experimental Tests

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
MousalrezaFaramarzi Palangar ◽  
Mohammad Mirzaie
Keyword(s):  
Thermal Conductivity ◽  
Mathematical Model ◽  
Mathematical Models ◽  
Experimental Tests ◽  
The Other ◽  
Critical Voltage ◽  
Nonlinear Behaviour ◽  
New Model ◽  
The Relationship ◽  
Good Agreement

In this paper, an improved mathematical model for flashover behavior of polluted insulators is proposed based on experimental tests. In order to determine the flashover model of polluted insulators, the relationship between conductivity and salinity of solution pollution layer of the insulator is measured. Then, the leakage of current amplitude of four common insulators versus axial, thermal conductivity and arc constants temperature was determined. The experimental tests show that top leakage distance (TLd) to bottom leakage distance (BLd) ratio of insulators has a significant effect on critical voltage and current. Therefore, critical voltage and current were modeled by TLd to BLd ratio Index (M). Also, salinity of solution pollution layer of the insulators has been applied to this model by resistance pollution parameter. On the other hand, arc constants of each insulator in new model have been identified based on experimental results. Finally, a mathematical model is intended for critical voltage against salinity of solution pollution layer of different insulators. This model depends on insulator profile. There is a good agreement between the experimental tests of pollution insulators obtained in the laboratory and values calculated from the mathematical models developed in the present study.

scholarly journals MEDIATION MODELS OF PREGNANCY DESIRES AND UNPLANNED PREGNANCY IN YOUNG, UNMARRIED WOMEN

2017 ◽  
Vol 50 (3) ◽  
pp. 291-311 ◽  
Author(s):  
Warren B. Miller ◽  
Jennifer S. Barber ◽  
Heather H. Gatny
Keyword(s):  
Logistic Regression ◽  
Unplanned Pregnancy ◽  
Sexual Partners ◽  
The Other ◽  
Regression Analyses ◽  
Number Of Factors ◽  
Women’S Perceptions ◽  
Predictive Strength ◽  
The Relationship ◽  
Mediation Models

SummaryThis paper examines the proposition that sexual and contraceptive behaviours mediate the relationship between the pregnancy desires of young, unmarried women and their having an unplanned pregnancy. The sample consisted of 854 18- to 19-year-old women living in Michigan, USA. First, the positive and negative pregnancy desires of these women were measured, as were the women’s perceptions of the positive and negative desires of their sexual partners. Then the extent to which these four types of desires, as well as several types of interactions between them, prospectively predicted the occurrence of subsequent pregnancies were tested with logistic regression analyses, initially alone and then after the addition of several types of sexual and contraceptive mediator variables. The results demonstrated that four of the ten significant motivational predictors became non-significant following the introduction of the contraceptive mediator variables and that the predictive strength of the other six significant motivational predictors was substantially reduced by their introduction. A number of factors that may account for only a partial mediational effect in some models are discussed.

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