Residual Strains in ITER Conductors by Neutron Diffraction

2014 ◽  
Vol 777 ◽  
pp. 84-91 ◽  
Author(s):  
Stefanus Harjo ◽  
Tsutomu Hemmi ◽  
Jun Abe ◽  
Wu Gong ◽  
Yoshihiko Nunoya ◽  
...  
Keyword(s):  
Residual Strain ◽  
High Field ◽  
Performance Test ◽  
Strain Difference ◽  
Thermal Strain ◽  
Field Zone ◽  
Cross Sectional ◽  
Strain Measurements ◽  
Peak Broadening ◽  
Residual Strains

Measurements of internal strains in the superconducting constituent (Nb3Sn phase in Nb3Sn strand) in two cable-in-conduit conductors (CICC) for International Thermonuclear Experimental Reactor were performed using an engineering materials diffractometer TAKUMI of J-PARC. From strain measurements in a CICC for the toroidal field magnet after a performance test of cyclic current, in 100 mm long cut bars, a peak broadening and a large relaxation on residual strain were observed in Nb3Sn phase at a portion received a high magnetic field (high field zone). Internal strain measurements were also conducted in a CICC for the central solenoidal magnets after the similar performance test, in the full-size shape as used in the performance test (3.6 m long) and in 100 mm long cut bars. Three main results were obtained. (1) Residual strain difference before and after the cutting to 100 mm long bar was about 0.1%, (2) a large relaxation on residual thermal strain was observed at the high field zone, and (3) the large relaxation on residual thermal strain at the high field zone was found mainly in a cross sectional side where the Lorentz force coming in.

scholarly journals An experimental study on the manufacture and characterization of in-plane fibre-waviness defects in composites

2018 ◽  
Vol 5 (5) ◽  
pp. 180082 ◽  
Author(s):  
W. J. R. Christian ◽  
F. A. DiazDelaO ◽  
K. Atherton ◽  
E. A. Patterson
Keyword(s):  
Residual Strain ◽  
Composite Structures ◽  
Computational Models ◽  
Image Correlation ◽  
Strain Fields ◽  
Strain Measurements ◽  
Ultrasound Measurements ◽  
Residual Strains ◽  
Failure Predictions

A new method has been developed for creating localized in-plane fibre waviness in composite coupons and used to create a large batch of specimens. This method could be used by manufacturers to experimentally explore the effect of fibre waviness on composite structures both directly and indirectly to develop and validate computational models. The specimens were assessed using ultrasound, digital image correlation and a novel inspection technique capable of measuring residual strain fields. To explore how the defect affects the performance of composite structures, the specimens were then loaded to failure. Predictions of remnant strength were made using a simple ultrasound damage metric and a new residual strain-based damage metric. The predictions made using residual strain measurements were found to be substantially more effective at characterizing ultimate strength than ultrasound measurements. This suggests that residual strains have a significant effect on the failure of laminates containing fibre waviness and that these strains could be incorporated into computational models to improve their ability to simulate the defect.

Neutron Diffraction Residual Strain Measurements in Plasma Sprayed Nanostructured Hydroxyapatite Coatings for Orthopaedic Implants

2010 ◽  
Vol 652 ◽  
pp. 309-314 ◽  
Author(s):  
Rehan Ahmed ◽  
Nadimul Haque Faisal ◽  
Stefan M. Knupfer ◽  
Anna Maria Paradowska ◽  
Michael E. Fitzpatrick ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Neutron Diffraction ◽  
Residual Strain ◽  
Strain Measurements ◽  
Strain Profile ◽  
Hydroxyapatite Coatings ◽  
Heat Treated ◽  
Residual Strains ◽  
Biomedical Coatings ◽  
Plasma Sprayed

Residual strains in plasma sprayed and heat-treated hydroxyapatite (HA) coatings deposited on a titanium alloy (Ti-6Al-4V) substrate were investigated by means of neutron diffraction. Strain measurements were performed in vertical scan (“z-scanning”) mode to provide a through thickness strain profile in the coating and substrate materials. Results are discussed in terms of the influence of heat-treatment on the residual strain profile of these biomedical coatings. This investigation concluded that the heat-treatment had a significant effect on the residual strain profile in HA coatings.

Regional and age-dependent residual strains, curvature, and dimensions of the human ureter

2017 ◽  
Vol 232 (2) ◽  
pp. 149-162 ◽  
Author(s):  
Despoina C Petsepe ◽  
Stavros K Kourkoulis ◽  
Stavroula A Papadodima ◽  
Dimitrios P Sokolis
Keyword(s):  
Lamina Propria ◽  
Wall Thickness ◽  
Residual Strain ◽  
Strain Difference ◽  
Biomechanical Properties ◽  
Muscle Layer ◽  
Opening Angle ◽  
Human Cadavers ◽  
Residual Strains ◽  
Human Ureter

The ureters are retroperitoneal structures controlling urine transport from the kidneys to the bladder. Because of the relative scarcity of data on the biomechanical properties of human ureter and the established importance of knowing these properties for understanding its physiology, we initiated biomechanical studies in cadaveric tissue. Herein, we report definite zero-stress/no-load geometrical characterization at 15 regions along the ureter of human cadavers aged 23–82 years, estimating the opening angle, circumferential residual strains, axial curvature, and dimensional parameters. Opening angle decreased along the proximal 25% of ureter, increased and reached a maximum near the mid-ureter, and then gradually decreased toward the vesicoureteral junction (young: p < 0.05; middle-aged: p < 0.05; old: p > 0.05; males: p < 0.05; females: p < 0.05). Similar were the regional distributions of residual strain at the interface between epithelium–lamina propria and muscle and of internal but not external residual strain. Wall thickness increased steadily with aging ( p < 0.05 at few regions), while ureteral circumference did not ( p > 0.05 at most regions) and opening angle decreased ( p < 0.05 at several regions). Consistent with Fung’s stress-growth law, the muscle layer thickened with age unlike the epithelium–lamina propria that thinned ( p < 0.05 at most regions for both thicknesses). Moderate-to-strong direct correlations of residual strain difference (= external – internal) with opening angle, wall thickness, and curvature were found in most ureters. The presented data will provide insight into the biomechanical response of ureter under zero/low-stress conditions and the relationship between ureteral remodeling and aging. Importantly, they may also be used to inform finite element models and computational studies simulating the ureter.

scholarly journals Higher dietary diversity is related to better visual and auditory sustained attention

2016 ◽  
Vol 115 (8) ◽  
pp. 1470-1480 ◽  
Author(s):  
Farideh Shiraseb ◽  
Fereydoun Siassi ◽  
Mostafa Qorbani ◽  
Gity Sotoudeh ◽  
Reza Rostami ◽  
...  
Keyword(s):  
Sustained Attention ◽  
Performance Test ◽  
Dietary Diversity ◽  
Continuous Performance Test ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Sports Clubs ◽  
Dietary Recall ◽  
Effective Performance ◽  
The Mean

AbstractAttention is a complex cognitive function that is necessary for learning, for following social norms of behaviour and for effective performance of responsibilities and duties. It is especially important in sensitive occupations requiring sustained attention. Improvement of dietary diversity (DD) is recognised as an important factor in health promotion, but its association with sustained attention is unknown. The aim of this study was to determine the association between auditory and visual sustained attention and DD. A cross-sectional study was carried out on 400 women aged 20–50 years who attended sports clubs at Tehran Municipality. Sustained attention was evaluated on the basis of the Integrated Visual and Auditory Continuous Performance Test using Integrated Visual and Auditory software. A single 24-h dietary recall questionnaire was used for DD assessment. Dietary diversity scores (DDS) were determined using the FAO guidelines. The mean visual and auditory sustained attention scores were 40·2 (sd35·2) and 42·5 (sd38), respectively. The mean DDS was 4·7 (sd1·5). After adjusting for age, education years, physical activity, energy intake and BMI, mean visual and auditory sustained attention showed a significant increase as the quartiles of DDS increased (P=0·001). In addition, the mean subscales of attention, including auditory consistency and vigilance, visual persistence, visual and auditory focus, speed, comprehension and full attention, increased significantly with increasing DDS (P<0·05). In conclusion, higher DDS is associated with better visual and auditory sustained attention.

Direct measurement of transverse residual strains in aorta

1996 ◽  
Vol 270 (2) ◽  
pp. H750-H759 ◽  
Author(s):  
H. C. Han ◽  
Y. C. Fung
Keyword(s):  
Stress State ◽  
Outer Layer ◽  
Residual Strain ◽  
Longitudinal Axis ◽  
Outer Wall ◽  
Residual Strains ◽  
Stress States ◽  
Sectional Surface ◽  
Thoracic And Abdominal ◽  
Load State

Residual strains were measured in the porcine aorta. Segments were cut from the aorta perpendicular to its longitudinal axis. Microdots of water-insoluble black ink were sprinkled onto the transverse sectional surface of the segments in the no-load state. The segments were then cut radially, and sectional zero-stress states were approached. The coordinates of selected microdots (2-20 microns) were digitized from photographs taken in the no-load state and the zero-stress state. Residual strains in the transverse section were calculated from the displacement of the microdots. The circumferential residual strains on the inner wall and outer wall were calculated from the circumferential lengths in the no-load state and the zero-stress state. Results show that the circumferential residual strain is negative (compressive) in the inner layer of the aortic wall and positive (tensile) in the outer layer, whereas the radial residual strain is tensile in the inner layer and compressive in the outer layer. This residual strain distribution reduces the stress concentration in the aorta under physiological load. The experimental results compared well with theoretical estimations of a cylindrical model. Regional difference of the residual strain exists and is significant (P < 0.01), e.g., the circumferential residual strains on the inner wall of the ascending, descending thoracic, and abdominal regions of the aorta are -0.133 +/- 0.019, -0.074 +/- 0.020, and -0.046 +/- 0.017 (mean +/- SD), respectively. More radial cuts of a segment produced no significant additional strains. This means that an aortic segment after one radial cut can be considered as the zero-stress state.

scholarly journals Accuracy of Two-dimensional Ultrasound and Magnetic Resonance Imaging in Diagnosis of Foetal Congenital Anomalies in a Tertiary Care Hospital- A Cross-sectional Study

2021 ◽  
Author(s):  
Jaybrata Ray ◽  
Jaharlal Baidya ◽  
Tanusri Debbarma ◽  
Jobin Joy
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Congenital Anomalies ◽  
High Field ◽  
Cross Sectional Study ◽  
3 Tesla ◽  
Sectional Study ◽  
Resonance Imaging ◽  
Cross Sectional ◽  
3 Tesla Mri

Introduction: Ultrasound screening for foetus congenital malformations is the mainstay in diagnosis and is commonly performed at 19-22 weeks gestation. Magnetic Resonance Imaging (MRI) is known as a problem solving tool which is used for answering a specific question. Both ultrasound and foetus MRI are highly sensitive and specific in diagnosis of congenital anomalies of the foetus with high agreement between both modalities. Aim: To determine the accuracy of Ultrasound Sonography (USG) and High Field 3 tesla MRI in diagnosis of different types of foetal Central Nervous System (CNS) and non CNS congenital abnormalities. Materials and Methods: A cross-sectional study was conducted in the Department of Radiodiagnosis at Agartala Government Medical College and GB Pant Hospital from June 2017 to May 2019. A total of 65 cases with ultrasound diagnosis of foetus abnormalities were examined by 3 Tesla MRI. MRI were performed within 15 days after USG detected anomalies. Statistical analysis was done using Chi-square test. Results: In cases with foetus anomalies high field MRI provided detailed findings leading to a more refined diagnosis. CNS anomalies were more as compared to other anomalies. Some of the antenatal findings were confirmed in some cases following termination of pregnancy and some were by postnatal examination. Among them chest anomalies was least common i.e., 1.5%. sensitivity of MRI was 88.13%, specificity was 66.66%, Positive Pressure Ventilation (PPV) was 96.29%, Negative Predictive Value (NPV) was 36.36% and USG sensitivity was 82.43%, specificity and 77.77%, PPV was 95.83%and NPV was 41.17%. Conclusion: High field MRI should be used as a second line of investigation in patients with foetus abnormalities diagnosed by ultrasound for confirmation of diagnosis and selecting the treatment protocol. In cases of fatal abnormalities, a confirmed diagnosis made before 20 weeks of pregnancy may help by terminating the pregnancy.

scholarly journals Effect of noise on fatigue: correlation between the subjective and objective indicators

2019 ◽  
Author(s):  
Jalil Derakhshan ◽  
Majid Moatamedzadeh ◽  
Rostam Golmohammadi ◽  
Mohammad Babamiri ◽  
Maryam Farhadian
Keyword(s):  
Performance Test ◽  
Continuous Performance Test ◽  
Cross Sectional Study ◽  
The Body ◽  
Continuous Performance ◽  
Cross Sectional ◽  
Measurement Results ◽  
Before And After ◽  
Fatigue Measurement ◽  
Objective Indicators

Introduction: Fatigue is the exhaustion of the body or spirit that can be caused by stress, excessive work, drug use, physical or mental illness. Fatigue is a factor in reducing productivity and incidents. Therefore, measuring fatigue is important. The aim of this study was to determine the fatigue measurement based on subjective and objective indices. Method: A cross-sectional study was performed on 120 male and female students. By simulating the real environment of each person in the 50 and 70dB pressure levels for 40 minutes, before and after exposure to noise, the amount of mental fatigue was measured using the subjective index Visual Analog Scale (VAS) and the objective index continuous performance test (CPT).  The results were analyzed using paired t-test and Spearman correlation coefficient in SPSS 20 software. Results: Measurement results with both self-declaration scale and continuous performance test showed that mental exhaustion  was increased significantly after exposure to the mentioned pressure level, but the results of two methods were not consistent with each other. Conclusion: Considering that the VAS self-declaration scale is a subjective method, it seems that the mismatch of the two methods is more related to the ineffectiveness of this scale. Therefore, it is suggested that re-examination has to be done with more precise methods such as electroencephalogram.

The Influence of Thermo-Oxidative Degradation on the Behavior of Epoxy Shape Memory Polymers

2014 ◽  
Author(s):  
Kannan Dasharathi ◽  
John A. Shaw
Keyword(s):  
Glass Transition ◽  
Shape Memory ◽  
Residual Strain ◽  
Oxidative Degradation ◽  
Viscoelastic Behavior ◽  
Diglycidyl Ether ◽  
Strain Recovery ◽  
Recovery Ratio ◽  
Chemical Aging ◽  
Residual Strains

Results are reported from an ongoing experimental investigation of the effects of thermo-oxidative aging on the mechanical behavior of an epoxy shape memory polymer (SMP). Chemo-rheological degradation due to macromolecular scission and cross-linking is one of the main factors contributing to the chemical aging of thermo-responsive SMPs. This aging may manifest as residual strain or irreversible material property changes, which can affect the performance and limit the useful life of a SMP. A relatively new epoxy SMP based on the diglycidyl ether of bisphenol A is synthesized, and specimens are tested under uni-axial tension using a dynamic mechanical analyzer. Fundamental viscoelastic behavior and thermal expansion coefficients are first characterized, showing a glass transition near 60 °C. Shape memory cycle experiments are performed at shape fixing temperatures of 80, 125, 150 and 175 °C, and the effect of fixing time at each temperature is examined upon subsequent strain recovery at 80 °C. Performance parameters such as recovery ratio, speed of recovery and residual strain are quantified as a function of shape fixing time and temperature. No effect of chemical aging was seen at a fixing temperature of 80 °C, although the recovery ratio decreases initially with increasing fixing time and stabilizes near 92 %. Only minor effects of chemical aging are seen in the mechanical responses for fixing temperatures of 125 and 150 °C, but specimens exhibit progressively more noticeable color changes that indicate oxidation. Significant effects are observed at the highest fixing temperature of 175 °C, where chemical aging at longer fixing times results in a reduction in recovery rate across the rubber-glass transition temperature, progressively larger residual strains, lack of complete strain recovery at 80 °C, and higher temperatures to achieve 90 % strain recovery.

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