Plastic Energy Required for Fatigue Failure of Specimens Containing Cracks

1975 ◽  
Vol 97 (2) ◽  
pp. 172-178 ◽  
Author(s):  
Thang Bui-Quoc ◽  
Andre Biron
Keyword(s):  
Experimental Data ◽  
Crack Propagation ◽  
Hysteresis Loops ◽  
Mean Value ◽  
Repeated Loading ◽  
Plastic Energy ◽  
Propagation Law ◽  
The Mean ◽  
Damage Rule ◽  
Propagation Stage

A study is conducted to determine the plastic energy absorbed by a material subjected to cyclic loading during the crack propagation stage. The analysis is based on Liu’s elastoplastic solution for calculating the plastic energy around the crack tip combined with a modified crack propagation law. The plastic energy per cycle Δw is found to be dependent upon the fatigue crack length and therefore varies with the number of applied cycles. The mean value of this energy corresponds to the plastic energy obtained by measuring the area within the stress-strain hysteresis loops of the material under repeated loading. If fatigue damage is based on plastic energy, the trend of variation of Δw with the applied cycles in the present analysis shows that the application of the linear damage rule (such as Miner’s law) should be more successful in the low-cycle region than in the high-cycle region. This is consistent with experimental data.

scholarly journals Normalization in dynamic speckle analysis for non-destructive monitoring of speed of processes

2021 ◽  
Vol 2091 (1) ◽  
pp. 012002
Author(s):  
Elena Stoykova ◽  
Dimana Nazarova ◽  
Lian Nedelchev ◽  
Mikhail Levchenko ◽  
Nataliya Berberova-Buhova ◽  
...  
Keyword(s):  
Experimental Data ◽  
Mean Value ◽  
High Contrast ◽  
Object Surface ◽  
Laser Illumination ◽  
Dynamic Speckle ◽  
The Mean ◽  
Spatially Varying ◽  
Non Destructive

Abstract The paper is dedicated to analysis of normalized intensity-based pointwise algorithms for processing dynamic speckle images with spatially varying speckle statistics in non-destructive visualization of regions of faster or slower changes across an object. Both existing and newly proposed algorithms are analyzed. Extraction of speed of changes is done by acquiring correlated in time speckle images formed on the object surface under laser illumination. The studied algorithms have been applied to simulated low and high contrast speckle data. Their performance has been compared to processing of binary patterns as another approach for dealing with varying speckle statistics in the acquired images. The efficiency of the algorithms have been checked on the experimental data, including data in a compressed format. We have proven that the algorithms with normalization at successive instants by a sum of two intensities or a single intensity outperform as a whole the algorithms which apply the time-averaged estimates of the mean value and the variance of speckle intensity.

Energy response of S355 and 41Cr4 steel during fatigue crack growth process

2018 ◽  
Vol 53 (8) ◽  
pp. 663-675 ◽  
Author(s):  
Grzegorz Lesiuk ◽  
Mieczysław Szata ◽  
Dariusz Rozumek ◽  
Zbigniew Marciniak ◽  
José Correia ◽  
...  
Keyword(s):  
Experimental Data ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Stress Effect ◽  
Mean Stress ◽  
Mean Stress Effect ◽  
R Ratio ◽  
The Mean

In this research, a novel approach of the fatigue crack growth rate description has been proposed. Based on theoretical and experimental approach, the mean stress effect expressed by R-ratio is present in classical da/dN–Δ K diagram. According to energy approach – based on the irrevocably dissipated energy accumulated in material (hysteresis loop) during fatigue process – the mean stress effect can be minimalized. Experimental validation of the proposed model was performed using results of fatigue crack propagation data for S355 and 41Cr4 steels in terms of strain energy density parameter Δ S or cyclic J-integral range –Δ J. In contrast to the force approach based on Kmax (or Δ K), the energy parameters Δ S or Δ J represent unambiguously the fatigue crack propagation rate, without influence of mean stress effect – R-ratio. However, in near threshold range of kinetic fatigue fracture diagram, the energy parameter displays a slight dispersion of the experimental data. According to the crack closure theory and its U-Elber parameter, the dispersion of experimental data is decreased. Therefore, the crack closure effects have a high significance in energy model – similar to the ‘force approach’ based on Δ K concept.

scholarly journals Propagation of the Measurement Error and the Measured Mean of a Physical Quantity for Elementary Functions ax and loga x

2019 ◽  
Vol 64 (5) ◽  
pp. 371
Author(s):  
G. G. Rode
Keyword(s):  
Experimental Data ◽  
Physical Quantity ◽  
Functional Relation ◽  
Analytical Form ◽  
Mean Value ◽  
Physical Experiment ◽  
Elementary Functions ◽  
The Mean ◽  
Gaussian Weight ◽  
Propagation Rules

Rules have been obtained for the propagation of the error and the mean value for a measured physical quantity onto another one with a functional relation of the type ax or loga x between them. In essence, these rules are inherently based on the Gaussian weight scheme. Therefore, they should be valid in the framework of a real Gaussian weight scheme applied to discrete data of a real physical experiment (a sample). An analytical form that was used to present the rules concerned (“analytical propagation rules”) and their character allow the processing and the analysis of experimental data to be simplified and accelerated.

scholarly journals Renaissance Distribution for Statistically Failed Experiments

2019 ◽  
Vol 20 (13) ◽  
pp. 3250
Author(s):  
Roman Popov ◽  
Girish Karadka Shankara ◽  
Clemens von Bojničić-Kninski ◽  
Alexander Nesterov-Mueller
Keyword(s):  
Experimental Data ◽  
Standard Deviation ◽  
Statistical Data ◽  
Life Sciences ◽  
Mean Value ◽  
Affinity Maturation ◽  
Large Standard Deviation ◽  
Target Amino Acid ◽  
The Mean ◽  
True Values

Much of the experimental data, especially in life sciences, is considered to be useless if it demonstrates a large standard deviation from the mean value. The Renaissance distribution, as presented in this study, allows one to extract true values from such statistical data with large noise. To obtain proof of the Renaissance distribution, high-throughput synthesis of deep substitutions for a target amino acid sequence was performed, and the known epitope was identified in assay with human serum antibodies. In addition, the Renaissance distribution was shown to approach the epitope affinity maturation by the deep alanine substitution. The Renaissance distribution may have an impact in the development of novel specific drugs.

scholarly journals COVLIAS 1.0 vs. MedSeg: Artificial Intelligence-Based Comparative Study for Automated COVID-19 Computed Tomography Lung Segmentation in Italian and Croatian Cohorts

Diagnostics ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2367
Author(s):  
Jasjit S. Suri ◽  
Sushant Agarwal ◽  
Alessandro Carriero ◽  
Alessio Paschè ◽  
Pietro S. C. Danna ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Experimental Data ◽  
Computed Tomography ◽  
Characteristic Curve ◽  
Computing Time ◽  
Mean Value ◽  
Image Analysis System ◽  
Validation Data ◽  
Lung Segmentation ◽  
The Mean

(1) Background: COVID-19 computed tomography (CT) lung segmentation is critical for COVID lung severity diagnosis. Earlier proposed approaches during 2020–2021 were semiautomated or automated but not accurate, user-friendly, and industry-standard benchmarked. The proposed study compared the COVID Lung Image Analysis System, COVLIAS 1.0 (GBTI, Inc., and AtheroPointTM, Roseville, CA, USA, referred to as COVLIAS), against MedSeg, a web-based Artificial Intelligence (AI) segmentation tool, where COVLIAS uses hybrid deep learning (HDL) models for CT lung segmentation. (2) Materials and Methods: The proposed study used 5000 ITALIAN COVID-19 positive CT lung images collected from 72 patients (experimental data) that confirmed the reverse transcription-polymerase chain reaction (RT-PCR) test. Two hybrid AI models from the COVLIAS system, namely, VGG-SegNet (HDL 1) and ResNet-SegNet (HDL 2), were used to segment the CT lungs. As part of the results, we compared both COVLIAS and MedSeg against two manual delineations (MD 1 and MD 2) using (i) Bland–Altman plots, (ii) Correlation coefficient (CC) plots, (iii) Receiver operating characteristic curve, and (iv) Figure of Merit and (v) visual overlays. A cohort of 500 CROATIA COVID-19 positive CT lung images (validation data) was used. A previously trained COVLIAS model was directly applied to the validation data (as part of Unseen-AI) to segment the CT lungs and compare them against MedSeg. (3) Result: For the experimental data, the four CCs between COVLIAS (HDL 1) vs. MD 1, COVLIAS (HDL 1) vs. MD 2, COVLIAS (HDL 2) vs. MD 1, and COVLIAS (HDL 2) vs. MD 2 were 0.96, 0.96, 0.96, and 0.96, respectively. The mean value of the COVLIAS system for the above four readings was 0.96. CC between MedSeg vs. MD 1 and MedSeg vs. MD 2 was 0.98 and 0.98, respectively. Both had a mean value of 0.98. On the validation data, the CC between COVLIAS (HDL 1) vs. MedSeg and COVLIAS (HDL 2) vs. MedSeg was 0.98 and 0.99, respectively. For the experimental data, the difference between the mean values for COVLIAS and MedSeg showed a difference of <2.5%, meeting the standard of equivalence. The average running times for COVLIAS and MedSeg on a single lung CT slice were ~4 s and ~10 s, respectively. (4) Conclusions: The performances of COVLIAS and MedSeg were similar. However, COVLIAS showed improved computing time over MedSeg.

scholarly journals Dependence of the cut-off parameters for the cluster reconstruction on incident momenta

2018 ◽  
pp. 22-30
Author(s):  
Shinebayar Janchiv ◽  
Togoo Ravdandorj ◽  
Tursukh Amgalan ◽  
Otgonsuren Dalkhajav ◽  
Munkhjargal Lkhagvadorj
Keyword(s):  
Experimental Data ◽  
Power Law ◽  
Nuclear Emulsion ◽  
Mean Value ◽  
Incident Momentum ◽  
Cluster Number ◽  
Mean Values ◽  
Cone Algorithm ◽  
The Mean ◽  
Number Of Particles

In this work, firstly, we have determined the multiplicities of protons that are involved from projectiles to interactions, and secondly, the mean incident momentum using experimental data on the collisions of proton, helium, oxygen, silicon, and sulfur with the nuclear emulsion at 4.5A GeV/c. We have studied the dependences of clot numbers, number of particles in the clot, rapidity, and the mean azimuthal value on the variable dij, and the dependence of the cluster number on the mean value of the variable dij. Using the “Cone” algorithm for the clustering, we have precisely identified that the cut-off parameter to compose the clusters consisted of s and f tracks produced in (p, He, C, O, Si, S) + Em collisions decreases by the power law with mean values of incident momentum.

Long-period modulated superstructures in Pd-12.5 at.%Ce and Pd-15 at.%Ce alloys

1990 ◽  
Vol 48 (4) ◽  
pp. 164-165
Author(s):  
Noriyuki Kuwano ◽  
Masaru Itakura ◽  
Kensuke Oki
Keyword(s):  
Electron Microscopy ◽  
Mean Value ◽  
Heavy Elements ◽  
Arc Furnace ◽  
X Ray ◽  
Long Period ◽  
Ultra High Purity ◽  
Heat Treated ◽  
Atomic Scattering ◽  
The Mean

Pd-Ce alloys exhibit various anomalies in physical properties due to mixed valences of Ce, and the anomalies are thought to be strongly related with the crystal structures. Since Pd and Ce are both heavy elements, relative magnitudes of (fcc-fpd) are so small compared with <f> that superlattice reflections, even if any, sometimes cannot be detected in conventional x-ray powder patterns, where fee and fpd are atomic scattering factors of Ce and Pd, and <f> the mean value in the crystal. However, superlattices in Pd-Ce alloys can be analyzed by electron microscopy, thanks to the high detectability of electron diffraction. In this work, we investigated modulated superstructures in alloys with 12.5 and 15.0 at.%Ce.Ingots of Pd-Ce alloys were prepared in an arc furnace under atmosphere of ultra high purity argon. The disc specimens cut out from the ingots were heat-treated in vacuum and electrothinned to electron transparency by a jet method.

Partition Coefficient Ratios and Tumour Perfusion Studied with 85mKr and 133Xe

1987 ◽  
Vol 26 (06) ◽  
pp. 253-257
Author(s):  
M. Mäntylä ◽  
J. Perkkiö ◽  
J. Heikkonen
Keyword(s):  
Partition Coefficient ◽  
Partition Coefficients ◽  
Regional Blood Flow ◽  
Blood Perfusion ◽  
Compartmental Analysis ◽  
Malignant Tumour ◽  
Mean Value ◽  
Perfusion Rate ◽  
Biological Variables ◽  
The Mean

The relative partition coefficients of krypton and xenon, and the regional blood flow in 27 superficial malignant tumour nodules in 22 patients with diagnosed tumours were measured using the 85mKr- and 133Xe-clearance method. In order to minimize the effect of biological variables on the measurements the radionuclides were injected simultaneously into the tumour. The distribution of the radiotracers was assumed to be in equilibrium at the beginning of the experiment. The blood perfusion was calculated by fitting a two-exponential function to the measuring points. The mean value of the perfusion rate calculated from the xenon results was 13 ± 10 ml/(100 g-min) [range 3 to 38 ml/(100 g-min)] and from the krypton results 19 ± 11 ml/(100 g-min) [range 5 to 45 ml/(100 g-min)]. These values were obtained, if the partition coefficients are equal to one. The equations obtained by using compartmental analysis were used for the calculation of the relative partition coefficient of krypton and xenon. The partition coefficient of krypton was found to be slightly smaller than that of xenon, which may be due to its smaller molecular weight.

Detection of Soluble Fibrin Monomer Complexes in Blood by Means of Protamine Sulphate Test

1968 ◽  
Vol 20 (01/02) ◽  
pp. 044-049 ◽  
Author(s):  
B Lipiński ◽  
K Worowski
Keyword(s):  
Human Subjects ◽  
Coronary Thrombosis ◽  
Mean Value ◽  
Healthy Human ◽  
Protamine Sulphate ◽  
Soluble Fibrin ◽  
Fibrin Monomer ◽  
Dog Plasma ◽  
The Mean ◽  
Precipitable Protein

SummaryIn the present paper described is a simple test for detecting soluble fibrin monomer complexes (SFMC) in blood. The test consists in mixing 1% protamine sulphate with diluted oxalated plasma or serum and reading the optical density at 6190 Å. In experiments with dog plasma, enriched with soluble fibrin complexes, it was shown that OD read in PS test is proportional to the amount of fibrin recovered from the precipitate. It was found that SFMC level in plasma increases in rabbits infused intravenously with thrombin and decreases after injection of plasmin with streptokinase. In both cases PS precipitable protein in serum is elevated indicating enhanced fibrinolysis. In healthy human subjects the mean value of OD readings in plasma and sera were found to be 0.30 and 0.11, while in patients with coronary thrombosis they are 0.64 and 0.05 respectively. The origin of SFMC in circulation under physiological and pathological conditions is discussed.

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