scholarly journals Identifying and Minimising Uncertainty for Experimental Journal Bearing Studies

2005 ◽  
Vol 2005 (3) ◽  
pp. 221-231 ◽  
Author(s):  
G. D. Wale ◽  
D. Mba
Keyword(s):  
Measurement Errors ◽  
Best Practice ◽  
Journal Bearing ◽  
High Sensitivity ◽  
Lower Sensitivity ◽  
Sources Of Error ◽  
Wide Range ◽  
Experimental Errors ◽  
Source Of Information ◽  
Good Agreement

Over the last few decades, different experimental methods, with varying forms of data analysis, have been employed on a wide range of journal bearing types. Under these circumstances, it is not surprising that the results presented, and their accuracy, are subject to varying scatter. Many of the assessments have been rather imprecise, often using unquantified statements such as “generally good agreement with predictions.” Most authors seem to have accepted that the appreciable scatter of results, especially in the dynamic oil film coefficients, was inevitable. Uncertainty is defined as the estimate of the errors. Note that the estimate may often be too optimistic because some sources of error have not been identified. This paper highlights sources of error for experimental journal studies, including some associated with the measurement system and physical misalignment. It is intended that this paper presents a coherent source of information on best practice in the field of experimental bearing research, offering a clearly prescribed methodology to estimate uncertainty and reduce error. The results of calculations of the sensitivity of the dynamic bearing coefficients to experimental errors in some commonly used rig configurations are presented. It is shown that one of the excitation schemes gives significantly lower sensitivity, but even this scheme has quite high sensitivity to measurement errors, especially phase. In conclusion, some of the critical precautions in the search for good quality results for experimental journal bearing studies are described.

scholarly journals Comparative sensitivity evaluation for 122 CE-marked SARS-CoV-2 antigen rapid tests

2021 ◽  
Author(s):  
Heinrich Scheiblauer ◽  
Angela Filomena ◽  
Andreas Nitsche ◽  
Andreas Puyskens ◽  
Victor Corman ◽  
...  
Keyword(s):  
Market Access ◽  
High Sensitivity ◽  
Lower Sensitivity ◽  
Viral Loads ◽  
Sensitivity Evaluation ◽  
Independent Evaluation ◽  
Wide Range ◽  
German Healthcare System ◽  
Rapid Tests ◽  
Minimum Sensitivity

Abstract Objective Independent evaluation of the sensitivity of CE-marked SARS-CoV-2 antigen rapid diagnostic tests (Ag RDT) offered in Germany. Method The sensitivity of 122 Ag RDT was adressed using a common evaluation panel. Minimum sensitivity of 75% for panel members with CT<25 was used for differentiation of devices eligible for reimbursement in in the German healthcare system. Results The sensitivity of different SARS-CoV-2 Ag RDT varied over a wide range. The sensitivity limit of 75% for panel members with CT <25 was met by 96 of the 122 tests evaluated; 26 tests exhibited lower sensitivity, few of which were completely failing. Some devices exhibited high sensitivity, e.g. 100% for CT<30. Conclusion This comparative evaluation succeeded to distinguish less sensitive from better performing Ag RDT. Most of the Ag RDT evaluated appear to be suitable for fast identification of acute infections associated with high viral loads. Market access of SARS-CoV-2 Ag RDT should be based on minimal requirements for sensitivity and specificity.

scholarly journals Comparative sensitivity evaluation for 122 CE-marked rapid diagnostic tests for SARS-CoV-2 antigen, Germany, September 2020 to April 2021

2021 ◽  
Vol 26 (44) ◽  
Author(s):  
Heinrich Scheiblauer ◽  
Angela Filomena ◽  
Andreas Nitsche ◽  
Andreas Puyskens ◽  
Victor M Corman ◽  
...  
Keyword(s):  
Diagnostic Tests ◽  
Market Access ◽  
High Sensitivity ◽  
Rapid Diagnostic Tests ◽  
Lower Sensitivity ◽  
Viral Loads ◽  
Sensitivity Evaluation ◽  
Wide Range ◽  
German Healthcare System ◽  
Minimum Sensitivity

Introduction Numerous CE-marked SARS-CoV-2 antigen rapid diagnostic tests (Ag RDT) are offered in Europe, several of them with unconfirmed quality claims. Aim We performed an independent head-to-head evaluation of the sensitivity of SARS-CoV-2 Ag RDT offered in Germany. Methods We addressed the sensitivity of 122 Ag RDT in direct comparison using a common evaluation panel comprised of 50 specimens. Minimum sensitivity of 75% for panel specimens with a PCR quantification cycle (Cq) ≤ 25 was used to identify Ag RDT eligible for reimbursement in the German healthcare system. Results The sensitivity of different SARS-CoV-2 Ag RDT varied over a wide range. The sensitivity limit of 75% for panel members with Cq ≤ 25 was met by 96 of the 122 tests evaluated; 26 tests exhibited lower sensitivity, few of which failed completely. Some RDT exhibited high sensitivity, e.g. 97.5 % for Cq < 30. Conclusions This comparative evaluation succeeded in distinguishing less sensitive from better performing Ag RDT. Most of the evaluated Ag RDT appeared to be suitable for fast identification of acute infections associated with high viral loads. Market access of SARS-CoV-2 Ag RDT should be based on minimal requirements for sensitivity and specificity.

scholarly journals The Problem Behaviour Checklist: short scale to assess challenging behaviours

BJPsych Open ◽  
2016 ◽  
Vol 2 (1) ◽  
pp. 45-49 ◽  
Author(s):  
Peter Tyrer ◽  
Jessica Nagar ◽  
Rosie Evans ◽  
Patricia Oliver ◽  
Paul Bassett ◽  
...  
Keyword(s):  
Factor Analysis ◽  
Interrater Reliability ◽  
Controlled Trial ◽  
High Sensitivity ◽  
Weighted Kappa ◽  
Challenging Behaviour ◽  
Problem Behaviour ◽  
Short Scale ◽  
Wide Range ◽  
Good Agreement

BackgroundChallenging behaviour, especially in intellectual disability, covers a wide range that is in need of further evaluation.AimsTo develop a short but comprehensive instrument for all aspects of challenging behaviour.MethodIn the first part of a two-stage enquiry, a 28-item scale was constructed to examine the components of challenging behaviour. Following a simple factor analysis this was developed further to create a new short scale, the Problem Behaviour Checklist (PBCL). The scale was subsequently used in a randomised controlled trial and tested for interrater reliability. Scores were also compared with a standard scale, the Modified Overt Aggression Scale (MOAS).ResultsSeven identified factors – personal violence, violence against property, self-harm, sexually inappropriate, contrary, demanding and disappearing behaviour – were scored on a 5-point scale. A subsequent factor analysis with the second population showed demanding, violent and contrary behaviour to account for most of the variance. Interrater reliability using weighted kappa showed good agreement (0.91; 95% CI 0.83–0.99). Good agreement was also shown with scores on the MOAS and a score of 1 on the PBCL showed high sensitivity (97%) and specificity (85%) for a threshold MOASscore of 4.ConclusionsThe PBCL appears to be a suitable and practical scale for assessing all aspects of challenging behaviour.

Hydrodynamic Analysis of Compliant Foil Bearings With Compressible Air Flow

2004 ◽  
Vol 126 (3) ◽  
pp. 542-546 ◽  
Author(s):  
Z.-C. Peng ◽  
M. M. Khonsari
Keyword(s):  
Carrying Capacity ◽  
Journal Bearing ◽  
Hydrodynamic Performance ◽  
Load Carrying Capacity ◽  
Bearing Surface ◽  
Hydrodynamic Analysis ◽  
Foil Bearings ◽  
Wide Range ◽  
Load Carrying ◽  
Good Agreement

A model is developed to predict the hydrodynamic performance of a foil journal bearing. The model accounts for both the compressibility of air and the compliance of the bearing surface. A series of predictions of the load-carrying capacity based on the numerical solution for pressure is presented that cover a wide range of operating speeds. The results show good agreement with existing experimental data.

scholarly journals Multifactorial assessment of measurement errors affecting intraoral quantitative sensory testing reliability

2017 ◽  
Vol 16 (1) ◽  
pp. 93-98 ◽  
Author(s):  
Estephan J. Moana-Filho ◽  
Aurelio A. Alonso ◽  
Flavia P. Kapos ◽  
Vladimir Leon-Salazar ◽  
Scott H. Durand ◽  
...  
Keyword(s):  
Measurement Error ◽  
Measurement Errors ◽  
Quantitative Sensory Testing ◽  
Linear Models ◽  
Intraclass Correlation ◽  
Sensory Testing ◽  
Multiple Sources ◽  
Cold Pain ◽  
Sources Of Error ◽  
Wide Range

AbstractBackground and purpose (aims)Measurement error of intraoral quantitative sensory testing (QST) has been assessed using traditional methods for reliability, such as intraclass correlation coefficients (ICCs). Most studies reporting QST reliability focused on assessingone source of measurement error at a time, e.g., inter- or intra-examiner (test–retest) reliabilities and employed two examiners to test inter-examiner reliability. The present study used a complex design with multiple examiners with the aim of assessing the reliability of intraoral QST taking account of multiple sources of error simultaneously.MethodsFour examiners of varied experience assessed 12 healthy participants in two visits separated by 48 h. Seven QST procedures to determine sensory thresholds were used: cold detection (CDT), warmth detection (WDT), cold pain (CPT), heat pain (HPT), mechanical detection (MDT), mechanical pain (MPT) and pressure pain (PPT). Mixed linear models were used to estimate variance components for reliability assessment; dependability coefficients were used to simulate alternative test scenarios.ResultsMost intraoral QST variability arose from differences between participants (8.8–30.5%), differences between visits within participant (4.6–52.8%), and error (13.3–28.3%). For QST procedures other than CDT and MDT, increasing the number of visits with a single examiner performing the procedures would lead to improved dependability (dependability coefficient ranges: single visit, four examiners = 0.12–0.54; four visits, single examiner = 0.27–0.68). A wide range of reliabilities for QST procedures, as measured by ICCs, was noted for inter- (0.39–0.80) and intra-examiner (0.10–0.62) variation.ConclusionReliability of sensory testing can be better assessed by measuring multiple sources of error simultaneously instead of focusing on one source at a time. In experimental settings, large numbers of participants are needed to obtain accurate estimates of treatment effects based on QST measurements. This is different from clinical use, where variation between persons (the person main effect) is not a concern because clinical measurements are done on a single person.ImplicationsFuture studies assessing sensorytestingreliabilityinboth clinicaland experimental settings would benefit from routinely measuring multiple sources of error. The methods and results of this study can be used by clinical researchers to improve assessment of measurement error related to intraoral sensorytesting. This should lead to improved resource allocation when designing studies that use intraoral quantitative sensory testing in clinical and experimental settings.© 2017 Scandinavian Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

COVID-19: knowledge, awareness and perceived stress among Jordanian healthcare providers (Preprint)

2020 ◽  
Author(s):  
Emad Aborajooh ◽  
Mohammed Qussay Al-Sabbagh ◽  
Baraa Mafrachi ◽  
Muhammad Yassin ◽  
Rami Dwairi ◽  
...  
Keyword(s):  
Social Media ◽  
Psychological Stress ◽  
Health Care Providers ◽  
Best Practice ◽  
Healthcare Providers ◽  
Cross Sectional Study ◽  
Care Providers ◽  
Cross Sectional ◽  
Ordinal Logistic Regression Analysis ◽  
Source Of Information

UNSTRUCTURED We aimed to measure levels of knowledge, awareness, and stress about COVID-19 among health care providers (HCP) in Jordan. This was a cross-sectional study on 397 HCPs that utilized an internet-based questionnaire to evaluate knowledge about COVID-19, availability of personal protective equipment (PEE), future perception, and psychological distress. Ordinal logistic regression analysis was used to evaluate factors associated with knowledge and psychological stress. Overall, 24.4% and 21.2% of the participants showed excellent knowledge and poor knowledge, respectively. Social media (61.7%) was the most commonly used source of information. Being female (β= 0.521, 95% CI 0.049 to 0.992), physician (β=1.421, 95% CI 0.849 to 1.992), or using literature to gain knowledge (β= 1.161, 95% CI 0.657 to 1.664) were positive predictors of higher knowledge. While having higher stress (β= -0.854, 95% CI -1.488 to -0.221) and using social media (β= -0.434, 95% CI -0.865 to -0.003) or conventional media (β= -0.884, 95% CI -1.358 to -0.409) for information were negative predictors of knowledge levels. HCPs are advised to use the literature as a source of information about the virus, its transmission, and the best practice. PPEs should be secured for HCPs to the psychological stress associated with treating COVID-19 patients.

scholarly journals Separate Universe calibration of the dependence of halo bias on cosmic web anisotropy

2020 ◽  
Vol 499 (3) ◽  
pp. 4418-4431 ◽  
Author(s):  
Sujatha Ramakrishnan ◽  
Aseem Paranjape
Keyword(s):  
Dark Matter ◽  
High Precision ◽  
Gaussian Distribution ◽  
Initial Perturbation ◽  
Analytical Framework ◽  
Web Environment ◽  
Wide Range ◽  
Galaxy Assembly ◽  
Very High ◽  
Good Agreement

ABSTRACT We use the Separate Universe technique to calibrate the dependence of linear and quadratic halo bias b1 and b2 on the local cosmic web environment of dark matter haloes. We do this by measuring the response of halo abundances at fixed mass and cosmic web tidal anisotropy α to an infinite wavelength initial perturbation. We augment our measurements with an analytical framework developed in earlier work that exploits the near-lognormal shape of the distribution of α and results in very high precision calibrations. We present convenient fitting functions for the dependence of b1 and b2 on α over a wide range of halo mass for redshifts 0 ≤ z ≤ 1. Our calibration of b2(α) is the first demonstration to date of the dependence of non-linear bias on the local web environment. Motivated by previous results that showed that α is the primary indicator of halo assembly bias for a number of halo properties beyond halo mass, we then extend our analytical framework to accommodate the dependence of b1 and b2 on any such secondary property that has, or can be monotonically transformed to have, a Gaussian distribution. We demonstrate this technique for the specific case of halo concentration, finding good agreement with previous results. Our calibrations will be useful for a variety of halo model analyses focusing on galaxy assembly bias, as well as analytical forecasts of the potential for using α as a segregating variable in multitracer analyses.

scholarly journals Gold–Carbon Nanocomposites for Environmental Contaminant Sensing

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 719
Author(s):  
Shahrooz Rahmati ◽  
William Doherty ◽  
Arman Amani Babadi ◽  
Muhamad Syamim Akmal Che Mansor ◽  
Nurhidayatullaili Muhd Julkapli ◽  
...  
Keyword(s):  
Environmental Pollutants ◽  
High Sensitivity ◽  
Environmental Crisis ◽  
World Population ◽  
Chemical Contaminants ◽  
Carbon Nanocomposites ◽  
Minimal Sample ◽  
Wide Range ◽  
And Control ◽  
Analytical Tools

The environmental crisis, due to the rapid growth of the world population and globalisation, is a serious concern of this century. Nanoscience and nanotechnology play an important role in addressing a wide range of environmental issues with innovative and successful solutions. Identification and control of emerging chemical contaminants have received substantial interest in recent years. As a result, there is a need for reliable and rapid analytical tools capable of performing sample analysis with high sensitivity, broad selectivity, desired stability, and minimal sample handling for the detection, degradation, and removal of hazardous contaminants. In this review, various gold–carbon nanocomposites-based sensors/biosensors that have been developed thus far are explored. The electrochemical platforms, synthesis, diverse applications, and effective monitoring of environmental pollutants are investigated comparatively.

scholarly journals 60–700 K CTAT and PTAT Temperature Sensors with 4H-SiC Schottky Diodes

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 942
Author(s):  
Razvan Pascu ◽  
Gheorghe Pristavu ◽  
Gheorghe Brezeanu ◽  
Florin Draghici ◽  
Philippe Godignon ◽  
...  
Keyword(s):  
Low Cost ◽  
Schottky Diodes ◽  
Schottky Contact ◽  
High Sensitivity ◽  
Xrd Analysis ◽  
Absolute Temperature ◽  
Lower Sensitivity ◽  
Readout Circuit ◽  
Sensing Element ◽  
High Performing

A SiC Schottky dual-diode temperature-sensing element, suitable for both complementary variation of VF with absolute temperature (CTAT) and differential proportional to absolute temperature (PTAT) sensors, is demonstrated over 60–700 K, currently the widest range reported. The structure’s layout places the two identical diodes in close, symmetrical proximity. A stable and high-barrier Schottky contact based on Ni, annealed at 750 °C, is used. XRD analysis evinced the even distribution of Ni2Si over the entire Schottky contact area. Forward measurements in the 60–700 K range indicate nearly identical characteristics for the dual-diodes, with only minor inhomogeneity. Our parallel diode (p-diode) model is used to parameterize experimental curves and evaluate sensing performances over this far-reaching domain. High sensitivity, upwards of 2.32 mV/K, is obtained, with satisfactory linearity (R2 reaching 99.80%) for the CTAT sensor, even down to 60 K. The PTAT differential version boasts increased linearity, up to 99.95%. The lower sensitivity is, in this case, compensated by using a high-performing, low-cost readout circuit, leading to a peak 14.91 mV/K, without influencing linearity.

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