scholarly journals Measurement of the Acoustic Non-Linearity Parameter of Materials by Exciting Reversed-Phase Rayleigh Waves in Opposite Directions

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1955 ◽  
Author(s):  
Bingsheng Yan ◽  
Yuzhou Song ◽  
Shijie Nie ◽  
Mingchao Yang ◽  
Ziran Liu
Keyword(s):  
Fatigue Damage ◽  
Rayleigh Waves ◽  
Detection Efficiency ◽  
Reversed Phase ◽  
Plate Structures ◽  
Micro Cracks ◽  
Element Simulation ◽  
Normal Transducer ◽  
To Receive ◽  
Test Result

The acoustic non-linearity parameter of Rayleigh waves can be used to detect various defects (such as dislocation and micro-cracks) on material surfaces of thick-plate structures; however, it is generally low and likely to be masked by noise. Moreover, conventional methods used with non-linear Rayleigh waves exhibit a low detection efficiency. To tackle these problems, a method of exciting reversed-phase Rayleigh waves in opposite directions is proposed to measure the acoustic non-linearity parameter of materials. For that, two angle beam wedge transducers were placed at the two ends of the upper surface of a specimen to excite two Rayleigh waves of opposite phases, while a normal transducer was installed in the middle of the upper surface to receive them. By taking specimens of 0Cr17Ni4Cu4Nb martensitic stainless steel subjected to fatigue damage as an example, a finite element simulation model was established to test the proposed method of measuring the acoustic non-linearity parameter. The simulation results show that the amplitude of fundamentals is significantly reduced due to offset, while that of second harmonics greatly increases due to superposition because of the opposite phases of the excited signals, and the acoustic non-linearity parameter thus increases. The experimental research on fatigue damage specimens was carried out using this method. The test result was consistent with the simulation result. Thus, the method of exciting reversed-phase Rayleigh waves in opposite directions can remarkably increase the acoustic non-linearity parameter. Additionally, synchronous excitation with double-angle beam wedge transducers can double the detection efficiency.

scholarly journals Oxygen saturation improved with nitrate-based nutritional formula in patients with COVID-19

2021 ◽  
Vol 49 (4) ◽  
pp. 030006052110123
Author(s):  
Sergej M. Ostojic ◽  
Aleksandra Milovancev ◽  
Patrik Drid ◽  
Alexandros Nikolaidis
Keyword(s):  
Oxygen Saturation ◽  
Patient Reported Outcomes ◽  
Case Series ◽  
Potassium Nitrate ◽  
Open Label ◽  
Patient Reported ◽  
Baseline Values ◽  
Study Participants ◽  
To Receive ◽  
Test Result

In this open-label case series trial, we evaluated the effects of a nitrate-based nutritional formula on oxygen saturation (SpO2) and patient-reported outcomes in individuals with coronavirus disease 2019 (COVID-19). Five adult patients (three men and two women, age 39.6 ± 6.9 years) with a positive COVID-19 test result, breathing difficulties, and SpO2 ≤95%, who were free from other pulmonary and cardiovascular conditions, were recruited for this study. Participants were assigned to receive a multi-component nutritional formula (containing 1200 mg of potassium nitrate, 200 mg of magnesium, 50 mg of zinc, and 1000 mg of citric acid) every 4 hours during the 48-hour monitoring period. In all participants, SpO2 improved immediately after administration of the nutritional formula, from 1 to 7 percentage points (mean increase 3.6 ± 2.7 points; 95% confidence interval 0.3 to 7.0). SpO2 remained above baseline values throughout the monitoring interval, with values persisting over threshold values (>92%) for all patients and at each time point during the 48 hours. No patients reported any side effects of the intervention. These promising and rather unexpected results call for immediate, well-sampled, mechanistic randomized controlled trials to validate our findings.

scholarly journals COVID-19 infection among international travellers: a prospective analysis

BMJ Open ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. e050667
Author(s):  
Meaghan Lunney ◽  
Paul E Ronksley ◽  
Robert G Weaver ◽  
Lianne Barnieh ◽  
Norman Blue ◽  
...  
Keyword(s):  
Critical Care ◽  
Outcome Measures ◽  
Contact Tracing ◽  
Prospective Analysis ◽  
Pilot Programme ◽  
Negative Test ◽  
Secondary Transmission ◽  
To Receive ◽  
Test Result

ObjectivesThis report estimates the risk of COVID-19 importation and secondary transmission associated with a modified quarantine programme in Canada.Design and participantsProspective analysis of international asymptomatic travellers entering Alberta, Canada.InterventionsAll participants were required to receive a PCR COVID-19 test on arrival. If negative, participants could leave quarantine but were required to have a second test 6 or 7 days after arrival. If the arrival test was positive, participants were required to remain in quarantine for 14 days.Main outcome measuresProportion and rate of participants testing positive for COVID-19; number of cases of secondary transmission.ResultsThe analysis included 9535 international travellers entering Alberta by air (N=8398) or land (N=1137) that voluntarily enrolled in the Alberta Border Testing Pilot Programme (a subset of all travellers); most (83.1%) were Canadian citizens. Among the 9310 participants who received at least one test, 200 (21.5 per 1000, 95% CI 18.6 to 24.6) tested positive. Sixty-nine per cent (138/200) of positive tests were detected on arrival (14.8 per 1000 travellers, 95% CI 12.5 to 17.5). 62 cases (6.7 per 1000 travellers, 95% CI 5.1 to 8.5; 31.0% of positive cases) were identified among participants that had been released from quarantine following a negative test result on arrival. Of 192 participants who developed symptoms, 51 (26.6%) tested positive after arrival. Among participants with positive tests, four (2.0%) were hospitalised for COVID-19; none required critical care or died. Contact tracing among participants who tested positive identified 200 contacts; of 88 contacts tested, 22 were cases of secondary transmission (14 from those testing positive on arrival and 8 from those testing positive thereafter). SARS-CoV-2 B.1.1.7 lineage was not detected in any of the 200 positive cases.Conclusions21.5 per 1000 international travellers tested positive for COVID-19. Most (69%) tested positive on arrival and 31% tested positive during follow-up. These findings suggest the need for ongoing vigilance in travellers testing negative on arrival and highlight the value of follow-up testing and contact tracing to monitor and limit secondary transmission where possible.

Biomarker testing patterns and actionability in advanced non-small cell lung cancer (aNSCLC) at OneOncology (OneOnc).

2021 ◽  
Vol 39 (28_suppl) ◽  
pp. 287-287
Author(s):  
Ari M. Vanderwalde ◽  
Esprit Ma ◽  
Elaine Yu ◽  
Tania Szado ◽  
Richard Price ◽  
...  
Keyword(s):  
Performance Status ◽  
Ecog Performance Status ◽  
Personalized Care ◽  
Specimen Collection ◽  
Targeted Treatments ◽  
Biomarker Testing ◽  
Next Generation Sequencing Ngs ◽  
To Receive ◽  
Testing Patterns ◽  
Test Result

287 Background: Recent approvals of targeted treatments (tx) have improved personalized care in aNSCLC. Biomarker testing is crucial for patients (pts) to receive optimal tx expeditiously. This study examined aNSCLC biomarker testing and tx patterns at OneOnc. Methods: Pts diagnosed with aNSCLC (stage ≥ IIIb) from 1/1/2015 to 5/31/2020, aged ≥ 18 years, and with ≥ 1 visit ≤ 90 days of advanced (Adv) diagnosis (Dx) were retrospectively evaluated using the nationwide Flatiron Health electronic health record derived de-identified database from selected OneOnc sites. Descriptive analyses were conducted to evaluate testing patterns for ALK, BRAF, EGFR, KRAS, PD-L1, and ROS-1 biomarkers and actionable mutation tx pattern. Results: Overall 3,860 aNSCLC pts were included, median age was 69 years, 47% females, 66% non-squamous, 29% squamous, 4% histology NOS, and 23% with ECOG performance status 0-1. Of the 3,152 (82%) pts tested for any biomarker, 64% received next-generation sequencing (NGS) vs. 36% received other biomarker tests only. Testing rates varied by biomarker: EGFR (74%), ALK (72%), ROS-1 (66%), PD-L1 (57%), BRAF (56%), KRAS (54%). Pts who received all 6 biomarker tests increased from 12% (2015), 23% (2016), 40% (2017), 41% (2018), 48% (2019) to 56% (2020). Among the tested pts, the median time from Adv Dx to the first test result was 20 days (d) and from specimen collection after Adv Dx to the first test result was 12 d. Pts tested and treated before test result available declined from 28% (2015) to 16% (2020). Of 1,207 pts with actionable mutations, 390 (32%) received tx before the test result: 35% chemotherapy (chemo) only, 28% chemo + cancer immunotherapy (CIT), and 15% CIT only. After the test result, 26% to 81% of pts received no or other tx not specific to actionable mutations [Table]. Conclusions: Findings from this study demonstrated an increase in aNSCLC biomarker testing at OneOnc over time, while 44% pts in 2020 did not receive testing on all 6 biomarkers. Some pts had tx prior to the test result, but this trend appeared to decline. Further studies are warranted to better understand the reasons for pts receiving tx that were not specific to their actionable mutations.[Table: see text]

scholarly journals Colposcopy Information Leaflets: What Women Want to Know and When They Want to Receive This Information

2003 ◽  
Vol 10 (3) ◽  
pp. 143-147 ◽  
Author(s):  
J Byrom ◽  
P D J Dunn ◽  
G M Hughes ◽  
J Lockett ◽  
A Johnson ◽  
...  
Keyword(s):  
National Health Service ◽  
Health Service ◽  
Screening Programme ◽  
Cervical Screening ◽  
Screening Process ◽  
Counselling Session ◽  
Information Leaflets ◽  
To Receive ◽  
Test Result ◽  
Colposcopy Clinic

Objectives: To evoluate whether the information leoflets produced by UK colposcopy clinics provide women with the information they desire and to determine when they would like to receive this information. Design: Questionnaire study and structured evaluation. Setting: The colposcopy clinic of a UK cancer centre. Participants: Forty-two women attending a pre-colposcopy counselling session and 100 consecutive women attending the colposcopy clinic. Methods: Thirty-eight standards derived from the concerns/questions asked by women attending a pre-colposcopy counselling session were used to assess locally produced colposcopy clinic leaflets from UK colposcopy clinics, the leaflets produced by the Royal College of Obstetricians and Gynaecologists and the National Health Service Cervical Screening Programme (NHSCSP), and two “leaflets” obtained from internet sites. The Gunning fog test was used to assess the leaflets' readability. A questionnaire survey of 100 women attending the colposcopy clinic was used to determine when women wanted to receive information about colposcopy. Main outcome measures: Percentage of questions answered by a given leaflet and Gunning fog scores for readability. Results: The information leaflets of 128 colposcopy clinics were received and assessed. Thirty-two clinics only sent women the NHSCSP leaflet. No leaflet answered all 38 questions. Less than half (36/100) of the leaflets answered more than 50% of the questions. In addition to the lack of advice given, different leaflets frequently gave conflicting advice. The average Gunning fog score was 9.7 (range 5.5–15.5). The majority of women (70%) wanted to receive information about colposcopy at or prior to the time of receiving their abnormal smear test result, although only 42% of women actually received information at this time. Conclusions: Many UK colposcopy clinics do not appear to be providing women with the information they require to understand their condition and the procedure that they are about to undergo. Furthermore, this information is often not provided at the appropriate time in the screening process.

scholarly journals Analysis of Flexural Fatigue Damage in Woven Glass-Polyester Composites

1997 ◽  
Vol 6 (2) ◽  
pp. 096369359700600 ◽  
Author(s):  
R. Elleuch ◽  
A. Chateauminois ◽  
Ch. Bradai
Keyword(s):  
Quantitative Analysis ◽  
Fatigue Damage ◽  
Fatigue Behaviour ◽  
Fiber Bundles ◽  
Flexural Fatigue ◽  
Three Point Bending ◽  
Micro Cracks ◽  
Polyester Composite ◽  
Longitudinal Fiber ◽  
Polyester Composites

The monotonic and fatigue behaviour of a woven glass/polyester composite has been investigated under three-point bending conditions. Microscopic observations of the fatigue specimens revealed that the damage was mainly related to the early nucleation of transverse micro-cracks and delaminations along the longitudinal fiber bundles. From the quantitative analysis of the length and the orientation of these defects, it was possible to derive a lifetime criterion which was associated to a transition in damage mechanisms.

scholarly journals High-Precision Noncontact Guided Wave Tomographic Imaging of Plate Structures Using a DHB Algorithm

2020 ◽  
Vol 10 (12) ◽  
pp. 4360
Author(s):  
Junpil Park ◽  
Jaesun Lee ◽  
Zong Le ◽  
Younho Cho
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Detection Efficiency ◽  
Detection System ◽  
Automatic Detection ◽  
Guided Wave ◽  
Direct Access ◽  
Experimental Conditions ◽  
Plate Structures ◽  
Wide Range

The safety diagnostic inspection of large plate structures, such as nuclear power plant containment liner plates and aircraft wings, is an important issue directly related to the safety of life. This research intends to present a more quantitative defect imaging in the structural health monitoring (SHM) technique by using a wide range of diagnostic techniques using guided ultrasound. A noncontact detection system was applied to compensate for such difficulties because direct access inspection is not possible for high-temperature and massive areas such as nuclear power plants and aircraft. Noncontact systems use unstable pulse laser and air-coupled transducers. Automatic detection systems were built to increase inspection speed and precision and the signal was measured. In addition, a new Difference Hilbert Back Projection (DHB) algorithm that can replace the reconstruction algorithm for the probabilistic inspection of damage (RAPID) algorithm used for imaging defects has been successfully applied to quantitative imaging of plate structure defects. Using an automatic detection system, the precision and detection efficiency of data collection has been greatly improved, and the same results can be obtained by reducing errors in experimental conditions that can occur in repeated experiments. Defects were made in two specimens, and comparative analysis was performed to see if each algorithm can quantitatively represent defects in multiple defects. The new DHB algorithm presented the possibility of observing and predicting the growth direction of defects through the continuous monitoring system.

Analysis of Mechanical Properties of TiB2-TiC+Ni/TiAl/Ti Graded Materials Prepared by FAPAS

2011 ◽  
Vol 689 ◽  
pp. 33-38
Author(s):  
Ze Feng Liu ◽  
Qing Sen Meng ◽  
Shao Ping Chen ◽  
L.J. Liang ◽  
P.F. Xue
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Shear Fracture ◽  
Synthesis Process ◽  
Graded Materials ◽  
Element Simulation ◽  
Stress And Deformation ◽  
Nonlinear Finite Element Simulation ◽  
Residual Stress And Deformation ◽  
Test Result

TiB2-TiC+Ni/TiAl/Ti graded materials were prepared by field-activated pressure-assisted synthesis process (FAPAS) and the mechanical properties and residual stress were investigated. Shear fracture that occurs at the interface between the cermets and TiAl with the maximum shear strength of 85.88 MPa. The residual stress and deformation induced by the thermal effect of chemical reaction and Joule heat during the synthesis process were analyzed by nonlinear finite element simulation. It is demonstrated that the maximum equivalent residual stress locate in the transition layer between the ceramics and TiAl, consistent with the shear test result.

scholarly journals Pitting process visualization

2010 ◽  
Vol 58 (5) ◽  
pp. 57-66
Author(s):  
Michal Černý ◽  
Josef Filípek ◽  
Roman Požár
Keyword(s):  
Fatigue Damage ◽  
Development Process ◽  
Gear Tooth ◽  
Plastic State ◽  
Time Domain Simulation ◽  
Damage Development ◽  
Process Visualization ◽  
Micro Cracks ◽  
Tooth Sample ◽  
Material Volume

The paper describes time-domain simulation of gear pitting damage using animation program. Key frames have been used to create illusion of motion. The animation uses experimental results of high-cycle fatigue of material. The fatigue damage occurs in the nominal creep area on the side of the gear tooth sample loaded with variable-positioned Hertz pressure. By applying the force, the pressure cumulates between two convex surfaces. This phenomenon results in material damage under of curved surfaces in contact. Moreover, further damage has been registered on the surface. This is due to exceeding the elastic-plastic state limit and development of „tabs“. The tabs serve as origin of surface micro cracks powered by shear stress and enclosed grease pressure as well. This deformation and extreme pressures of Pascal law contribute to elongation and growth of the surface micro crack. Non-homogenous parts of material volume support the initialization/development of the micro cracks as well. Resulting visualization of the tooth-side fatigue damage provides clear and easy-to-understand description of the damage development process right from the micro crack initialization to the final fragmentation due to pitting degradation.

Evaluating Rolling Contact Fatigue Damage Precursors with Rayleigh Waves in 1060 Steel

2021 ◽  
Vol 40 (4) ◽  
Author(s):  
Changgong Kim ◽  
Yaswanth Sai Jetti ◽  
Alison C. Dunn ◽  
Kathryn H. Matlack
Keyword(s):  
Fatigue Damage ◽  
Rayleigh Waves ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact
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