scholarly journals COEFFICIENT OF SUBGRADE REACTION ESTIMATED FROM HORIZONTAL LOAD TEST DATA OF SINGLE PILES WITH WIDE RANGE DIAMETER IN COHESIVE SOIL DEPOSIT

2017 ◽  
Vol 23 (53) ◽  
pp. 93-98
Author(s):  
Shuichi SHIMOMURA ◽  
Yasutsugu SUZUKI
Keyword(s):  
Test Data ◽  
Cohesive Soil ◽  
Load Test ◽  
Horizontal Load ◽  
Subgrade Reaction ◽  
Wide Range ◽  
Single Piles

Analysis of Thick-Walled Pipeline Elements Operating in Creep Conditions

2015 ◽  
Vol 712 ◽  
pp. 63-68
Author(s):  
Przemysław Osocha ◽  
Bohdan Węglowski
Keyword(s):  
Finite Element ◽  
Test Data ◽  
Creep Test ◽  
Power Plants ◽  
Steam Pressure ◽  
Creep Model ◽  
Creep Process ◽  
Fe Model ◽  
Element Analysis ◽  
Wide Range

In some coal-fired power plants, pipeline elements have worked for over 200 000 hours and increased number of failures is observed. The paper discuses thermal wear processes that take place in those elements and lead to rupture. Mathematical model based on creep test data, and describing creep processes for analyzed material, has been developed. Model has been verified for pipeline operating temperature, lower than tests temperature, basing on Larson-Miller relation. Prepared model has been used for thermal-strength calculations based on a finite element method. Processes taking place inside of element and leading to its failure has been described. Than, basing on prepared mathematical creep model and FE model introduced to Ansys program further researches are made. Analysis of dimensions and shape of pipe junction and its influence on operational element lifetime is presented. In the end multi variable dependence of temperature, steam pressure and element geometry is shown, allowing optimization of process parameters in function of required operational time or maximization of steam parameters. The article presents wide range of methods. The creep test data were recalculated for operational temperature using Larson-Miller parameter. The creep strain were modelled, used equations and their parameters are presented. Analysis of errors were conducted. Geometry of failing pipe junction was introduced to the Ansys program and the finite element analysis of creep process were conducted.

Abrasion and Wear of Rubber. Analysis of Wear Curves

1952 ◽  
Vol 25 (1) ◽  
pp. 107-109
Author(s):  
J. M. Buist
Keyword(s):  
Mathematical Method ◽  
Test Data ◽  
Wear Test ◽  
Broad Application ◽  
Rubber Industry ◽  
Wide Range ◽  
Subsequent Discussion ◽  
Abrasion Testing ◽  
Wear Index

Abstract One of the difficulties of assessing wear test data of rubber articles, e.g., tires, soles and heels, etc., is the fact that the wear index is not necessarily constant throughout the wearing trial. In a previous publication it was suggested that before exact correlations could be established between laboratory and service tests some mathematical method of obtaining constant indexes for both tests must be found. In the subsequent discussion of this paper at Birmingham, the author revealed that wear curves obtained on the Martindale abrasion tester and also some actual road wear curves could be expressed satisfactorily by an equation of the type y=axn. Since that time further work has been done, and it is now proved that if wear curves obtained on a wide range of laboratory machines, e.g., Martindale, du Pont, and Dunlop (Lambourn), are plotted, these curves are all of the same family y=axn. Although this equation is purely empirical, it is of considerable interest to the rubber industry in that it has such a broad application in the field of laboratory abrasion testing and also in service wear trials.

scholarly journals High variability in transmission of SARS-CoV-2 within households and implications for control

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259097
Author(s):  
Damon J. A. Toth ◽  
Alexander B. Beams ◽  
Lindsay T. Keegan ◽  
Yue Zhang ◽  
Tom Greene ◽  
...  
Keyword(s):  
Test Data ◽  
Attack Rate ◽  
Serological Test ◽  
Close Contact ◽  
Antibody Test ◽  
High Variability ◽  
Test Accuracy ◽  
Household Transmission ◽  
Wide Range ◽  
Test Specificity

Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a high risk of transmission in close-contact indoor settings, which may include households. Prior studies have found a wide range of household secondary attack rates and may contain biases due to simplifying assumptions about transmission variability and test accuracy. Methods We compiled serological SARS-CoV-2 antibody test data and prior SARS-CoV-2 test reporting from members of 9,224 Utah households. We paired these data with a probabilistic model of household importation and transmission. We calculated a maximum likelihood estimate of the importation probability, mean and variability of household transmission probability, and sensitivity and specificity of test data. Given our household transmission estimates, we estimated the threshold of non-household transmission required for epidemic growth in the population. Results We estimated that individuals in our study households had a 0.41% (95% CI 0.32%– 0.51%) chance of acquiring SARS-CoV-2 infection outside their household. Our household secondary attack rate estimate was 36% (27%– 48%), substantially higher than the crude estimate of 16% unadjusted for imperfect serological test specificity and other factors. We found evidence for high variability in individual transmissibility, with higher probability of no transmissions or many transmissions compared to standard models. With household transmission at our estimates, the average number of non-household transmissions per case must be kept below 0.41 (0.33–0.52) to avoid continued growth of the pandemic in Utah. Conclusions Our findings suggest that crude estimates of household secondary attack rate based on serology data without accounting for false positive tests may underestimate the true average transmissibility, even when test specificity is high. Our finding of potential high variability (overdispersion) in transmissibility of infected individuals is consistent with characterizing SARS-CoV-2 transmission being largely driven by superspreading from a minority of infected individuals. Mitigation efforts targeting large households and other locations where many people congregate indoors might curb continued spread of the virus.

Predicting the Ultimate Bearing Capacity of Single Piles Based on CPTU

2011 ◽  
Vol 243-249 ◽  
pp. 4402-4407
Author(s):  
Yong Hong Miao ◽  
Guo Jun Cai ◽  
Song Yu Liu
Keyword(s):  
Load Test ◽  
Load Testing ◽  
Pile Capacity ◽  
Piezocone Penetration Test ◽  
Load Carrying ◽  
Load Tests ◽  
Pile Load Test ◽  
Single Piles ◽  
Pile Load Tests ◽  
Best Fit

Six methods to determine axial pile capacity directly based on piezocone penetration test (CPTU) data are presented and evaluated. Analyses and evaluation were conducted on three types piles that were failed during pile load testing. The CPT methods, as well as the CPTU methods, were used to estimate the load carrying capacities of the investigated piles (Qp ). Pile load test were used to determine the measured load carrying capacities (Qm). The pile capacities determined using the different methods were compared with the measured pile capacities obtained from the pile load tests. Two criteria were selected as bases of evaluation: the best fit line for Qp versus Qm and the arithmetic mean and standard deviation for the ratio Qp /Qm. Results of the analyses showed that the best methods for determining pile capacity are the CPTU methods.

scholarly journals Estimation of Transmissivity and Permeability in Swedish Bedrock

1977 ◽  
Vol 8 (2) ◽  
pp. 103-116 ◽  
Author(s):  
Leif Carlsson ◽  
Anders Carlstedt
Keyword(s):  
Statistical Analysis ◽  
Test Data ◽  
Hydraulic Properties ◽  
Pumping Test ◽  
Crystalline Rocks ◽  
Wide Range ◽  
Well Loss

Statistical analysis of pumping-test data from wells have been used to calculate average values of transmissivity and permeability in different Swedish rocks. The influence of the well-loss on the calculations is discussed. The highest values of transmissivity and permeability of the investigated rocks are found in the sandstones of Algonkian and Cambrian age. The Archean crystalline rocks show a wide range of results, and of the investigated rocks the gneisses seem to be more permeable than the granites. However, the degree of tectonization affects the hydraulic properties of the rocks considerably.

scholarly journals Simple primitive recognition via hierarchical face clustering

2020 ◽  
Vol 6 (4) ◽  
pp. 431-443
Author(s):  
Xiaolong Yang ◽  
Xiaohong Jia
Keyword(s):  
Hierarchical Clustering ◽  
Test Data ◽  
Efficient Algorithm ◽  
Clustering Algorithm ◽  
State Of The Art ◽  
Experimental Results ◽  
Face Clustering ◽  
Wide Range ◽  
Hierarchical Clustering Algorithm ◽  
Bottom To Top

AbstractWe present a simple yet efficient algorithm for recognizing simple quadric primitives (plane, sphere, cylinder, cone) from triangular meshes. Our approach is an improved version of a previous hierarchical clustering algorithm, which performs pairwise clustering of triangle patches from bottom to top. The key contributions of our approach include a strategy for priority and fidelity consideration of the detected primitives, and a scheme for boundary smoothness between adjacent clusters. Experimental results demonstrate that the proposed method produces qualitatively and quantitatively better results than representative state-of-the-art methods on a wide range of test data.

Fatigue-Life Prediction Method Based on Small-Crack Theory in an Engine Material

2011 ◽  
Vol 134 (3) ◽  
Author(s):  
James C. Newman ◽  
Balkrishna S. Annigeri
Keyword(s):  
Crack Closure ◽  
Test Data ◽  
High Cycle Fatigue ◽  
Fatigue Cracks ◽  
Loading Conditions ◽  
Cycle Fatigue ◽  
Constant Amplitude ◽  
Notched Specimens ◽  
Wide Range ◽  
Stress Ratios

Plasticity effects and crack-closure modeling of small fatigue cracks were used on a Ti-6Al-4V alloy to calculate fatigue lives under various constant-amplitude loading conditions (negative to positive stress ratios, R) on notched and un-notched specimens. Fatigue test data came from a high-cycle-fatigue study by the U.S. Air Force and a metallic materials properties handbook. A crack-closure model with a cyclic-plastic-zone-corrected effective stress-intensity factor range and equivalent-initial-flaw-sizes (EIFS) were used to calculate fatigue lives using only crack-growth-rate data. For un-notched specimens, EIFS values were 25-μm; while for notched specimens, the EIFS values ranged from 6 to 12 μm for positive stress ratios and 25-μm for R = −1 loading. Calculated fatigue lives under a wide-range of constant-amplitude loading conditions agreed fairly well with the test data from low- to high-cycle fatigue conditions.

Load tests on bedrock

1970 ◽  
Vol 7 (4) ◽  
pp. 464-470 ◽  
Author(s):  
J. L. Seychuk
Keyword(s):  
Elastic Material ◽  
Steel Plate ◽  
Applied Pressure ◽  
Load Test ◽  
Vertical Load ◽  
Subgrade Reaction ◽  
Concrete Piles ◽  
Limestone Bedrock ◽  
Load Tests ◽  
Pile Load Test

Load tests involving the use of a steel plate, a concrete socket, and full scale concrete piles were carried out at two separate sites in Ontario to determine the load bearing characteristics of shale and limestone bedrock. It was found that the essentially sound bedrock behaved as an elastic material under the maximum applied pressure of 260 tons/sq. ft (254 × 104 kg/m2). In addition to the vertical load tests on the rock, a lateral pile load test was carried out to evaluate the modulus of horizontal subgrade reaction of the fissured clay overburden at one of the sites.

Fatigue-Life Prediction Method Based on Small-Crack Theory in an Engine Material

2011 ◽  
Author(s):  
James C. Newman ◽  
Balkrishna S. Annigeri
Keyword(s):  
Crack Closure ◽  
Test Data ◽  
High Cycle Fatigue ◽  
Fatigue Cracks ◽  
Loading Conditions ◽  
Cycle Fatigue ◽  
Constant Amplitude ◽  
Notched Specimens ◽  
Wide Range ◽  
Stress Ratios

Plasticity effects and crack-closure modeling of small fatigue cracks were used on a Ti-6Al-4V alloy to calculate fatigue lives under various constant-amplitude loading conditions (negative to positive stress ratios, R) on notched and un-notched specimens. Fatigue test data came from a high-cycle-fatigue study by the U.S. Air Force and a metallic materials properties handbook. A crack-closure model with a cyclic-plastic-zone-corrected effective stress-intensity factor range and equivalent-initial-flaw-sizes (EIFS) were used to calculate fatigue lives using only crack-growth-rate data. For un-notched specimens, EIFS values were 25-μm; while for notched specimens, the EIFS values ranged from 6 to 12 μm for positive stress ratios and 25-μm for R = −1 loading. Calculated fatigue lives under a wide-range of constant-amplitude loading conditions agreed fairly well with the test data from low- to high-cycle fatigue conditions.

Sign in / Sign up

Export Citation Format

Share Document