35 research outputs found
Development of Traceable Capabilities in Non-Contact Thermal Metrology
Accurate temperature measurement is crucial in industry to reduce waste and environmental impact. Industrial use of Radiation Thermometers (RTs) is becoming increasingly common due to their wide market availability, fast response time, large temperature ranges, and their ability to measure temperature without contact. With this growth in use, accurate RT measurements that are traceable to the International Temperature Scale of 1990 (ITS-90) are a growing requirement. Traceable calibrations are usually performed using horizontal Blackbody Cavity Radiation Sources (BCRSs). In the work presented, a unique vertical bath-based BCRS, constructed in-house at the National Standards Authority of Ireland (NSAI), was compared over the range from -30 °C to 150 °C, against a suite of conventional horizontal bath-based BCRSs in overseas National Metrology Institutes (NMIs) and against a previous iteration of this new vertical design. Vertical bath-based BCRSs are more flexible and economical to use than horizontal BCRSs and can take advantage of existing calibration equipment.
In the comparison of BCRSs, it was found that the vertical orientation was comparable to within 0.25 °C of standard horizontal cavities for the range from -30 °C to 150 °C. It was concluded that the vertical configuration is an economical alternative for calibration of RTs within the range assessed. A conservative evaluation of the uncertainty of measurement found that it ranged from ±0.34 °C to ±0.66 °C (� = 2). Alongside this comparison, the calibration of direct-reading, handheld Infrared RTs (often simply referred to as IRTs) was investigated. These are lower-cost instruments that read directly in temperature and do not give access to the unprocessed detector signal. IRTs are the most common type of RT used in industry. IRTs are known to suffer from poor Size-of-Source Effects (SSEs), which introduce errors caused by scattered radiation from outside the IRT’s nominal target area. Variation in readings due to changes in proximity of the detector to the source – the Distance Effect (DE) – has also been found to cause significant errors in IRTs. In the present work, best practice calibration procedures and uncertainty budgets were investigated for IRTs using a case study instrument. The instrument was calibrated over the range from -30 °C to 900 °C, and its SSE and Distance Effect (DE) were measured. The test case IRT’s SSE was measured at three different temperatures to determine its true field of view. The IRT was also tested at five target distances and using a variety of radiation sources to calibrate it and determine its DE. The IRT was found to exceed its specification by 3.7 °C when measuring an 800 °C BCRS and was out of specification across most of the rest of its range. At 500 °C, the IRT reading was found to vary by 1.75 °C across a 500 mm range of distances. The IRT reading was also found to drift by up to 2 °C when kept exposed to a 500 °C source for an hour.
The case study of the IRT highlighted the importance of providing detailed calibration conditions, particularly regarding calibration geometry, IRT housing temperature, and exposure duration. As well as aiding in the establishment of a fit-for-purpose high-level non-contact calibration capability at NSAI, the work presented details a method by which other NMIs can inexpensively develop RT calibration facilities without custombuilt baths
Development and characterisation of a bath-based vertical blackbody cavity calibration source for the range −30 °C to 150 °C
Industrial use of Radiation Thermometers (RTs) is becoming increasingly common due to the perceived advantages and wide market availability. Blackbody Cavity Radiation Sources (BCRSs) are typically used for calibration of these instruments, and these cavities are oriented horizontally in most cases. For BCRSs based in thermal baths, this necessitates the use of custom-built baths with side openings. This paper presents a unique design of vertical bath-based BCRS that may be immersed in conventional calibration baths without modifications to the baths. The method, results, and analysis of an international comparison comparing this vertical BCRS, standard horizontal BCRSs, and a previous iteration of the vertical design of BCRS are also presented. The comparison was conducted through collaboration between the Laboratory of Metrology and Quality, Slovenia (LMK) and the National Standards Authority Ireland (NSAI), with the intention of evaluating the suitability of the vertical orientation for calibration work. Transfer pyrometers and Standard Platinum Resistance Thermometers (SPRTs) were used as comparison standards. The transfer pyrometers used have spectral sensitivity from 8μm to 14μm in this temperature range. It was found that the vertical orientation was comparable to within 0.25°Cthroughout the range to standard horizontal cavities. It was concluded that a vertical configuration is an economical alternative for calibration of RTs within the range assessed
Tissue Factor and Tissue Factor Pathway Inhibitor as Key Regulators of Global Hemostasis: Measurement of Their Levels in Coagulation Assays
The tissue factor (TF)/factor (F)VIIa complex is the primary initiator of coagulation in vivo. Tissue factor pathway inhibitor (TFPI) is the physiological inhibitor of the TF/FVIIa complex. Deficiencies of either TF or TFPI have not been reported in humans, and a complete absence of either of these two proteins in mice is embryonically lethal. To maintain normal hemostasis, levels of TF and TFPI need to be balanced. Increased levels of TF can overwhelm the inhibitory capacity of TFPI, resulting in thrombosis. Decreased levels of TF are associated with bleeding. Global assays of coagulation are defined as tests capable of evaluating all components of the clotting cascade that are present in plasma. In these tests the thrombogenic surface is either provided by platelets or exogenous phospholipids. Clotting assays currently used in clinical practice are not designed to measure endogenous levels of TF and TFPI. Therefore, there is a need to develop sensitive and specific assays for measuring levels of functional TF and TFPI in whole blood and plasma. These assays could be useful in patient management in many scenarios
Speeding-up Scientific Knowledge Transfer and Improvement of Capabilities of emerging European National Metrology Institutes and Designated Institutes in the field of thermal measurements: Benefits and Impacts
Within the frame of a European project called Eura-Thermal, the general objective was to upgrade the regional metrological infrastructure (Bosnia & Herzegovina, Croatia, Ireland, Serbia...) with new capabilities, especially in the field of thermal measurements. This paper highlights the strategy used for improving in the short term, scientific knowledge transfer and the capabilities of different emerging institutes. Furthermore, as a main output, the impacts and benefit for Industry and for the end-users are also presented as examples. © 2018 Institute of Physics Publishing. All rights reserved.XXII World Congress of the International Measurement Confederation (IMEKO 2018
Bedrock geology of DFDP-2B, central Alpine Fault, New Zealand
<p>During the second phase of the Alpine Fault, Deep Fault Drilling Project (DFDP) in the Whataroa River, South Westland, New Zealand, bedrock was encountered in the DFDP-2B borehole from 238.5–893.2 m Measured Depth (MD). Continuous sampling and meso- to microscale characterisation of whole rock cuttings established that, in sequence, the borehole sampled amphibolite facies, Torlesse Composite Terrane-derived schists, protomylonites and mylonites, terminating 200–400 m above an Alpine Fault Principal Slip Zone (PSZ) with a maximum dip of 62°. The most diagnostic structural features of increasing PSZ proximity were the occurrence of shear bands and reduction in mean quartz grain sizes. A change in composition to greater mica:quartz + feldspar, most markedly below c. 700 m MD, is inferred to result from either heterogeneous sampling or a change in lithology related to alteration. Major oxide variations suggest the fault-proximal Alpine Fault alteration zone, as previously defined in DFDP-1 core, was not sampled.</p
Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial
SummaryBackground Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatoryactions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19.Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospitalwith COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients wererandomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once perday by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatmentgroups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment andwere twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants andlocal study staff were not masked to the allocated treatment, but all others involved in the trial were masked to theoutcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treatpopulation. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936.Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) wereeligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomlyallocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall,561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days(rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days(rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, nosignificant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilationor death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24).Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or otherprespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restrictedto patients in whom there is a clear antimicrobial indication
Applying natural language processing to automatically assess student conceptual understanding from textual responses
In this study, we applied natural language processing (NLP) techniques, within an educational environment, to evaluate their usefulness for automated assessment of students’ conceptual understanding from their short answer responses. Assessing understanding provides insight into and feedback on students’ conceptual understanding, which is often overlooked in automated grading. Students and educators benefit from automated formative assessment, especially in online education and large cohorts, by providing insights into conceptual understanding as and when required. We selected the ELECTRA-small, RoBERTa-base, XLNet-base and ALBERT-base-v2 NLP machine learning models to determine the free-text validity of students’ justification and the level of confidence in their responses. These two pieces of information provide key insights into students’ conceptual understanding and the nature of their understanding. We developed a free-text validity ensemble using high performance NLP models to assess the validity of students’ justification with accuracies ranging from 91.46% to 98.66%. In addition, we proposed a general, non-question-specific confidence-in-response model that can categorise a response as high or low confidence with accuracies ranging from 93.07% to 99.46%. With the strong performance of these models being applicable to small data sets, there is a great opportunity for educators to implement these techniques within their own classes. Implications for practice or policy: Students’ conceptual understanding can be accurately and automatically extracted from their short answer responses using NLP to assess the level and nature of their understanding. Educators and students can receive feedback on conceptual understanding as and when required through the automated assessment of conceptual understanding, without the overhead of traditional formative assessment. Educators can implement accurate automated assessment of conceptual understanding models with fewer than 100 student responses for their short response questions
A three-year longitudinal textual analysis investigation of students' conceptual understanding: Lessons learnt and implications for teaching
Concept inventories are specific tests, designed to elicit misunderstandings or misconceptions. They are a set of multiple-choice questions (MCQs), designed to include the correct option, as well several distractors (Libarkin, 2008). One attractive advantage of the ease of scoring concept inventories, is their MCQ format. However, this same format does not detect whether students arrived at their correct answers by pure guessing. By adding a space for students to add a textual justification (Goncher, Jayalath and Boles, 2016), their answers can be checked to ensure that the concepts are correctly understood. From this study, the concepts causing persistent difficulties to students were explored. Several persistent misconceptions were identified over the 3 years, both with low correct rates, and high guessing rates. The added textual component to the usual multiple choice response made this inferences possible
Linking numerical scores with sentiment analysis of students' teaching and subject evaluation surveys: Pointers to teaching enhancements
Student evaluations of teaching and subjects are systematically used at many educational institutions, to get students’ feedback. They usually consist of a number of questions where students can anonymously provide their responses on 5 or 7-point Likert scales, with provision to provide free comments. There are several different ways of evaluating student satisfaction (Elliott, 2002) and the numerical scores are often taken as the main indicator of student satisfaction, although much insight can be gained from analysing the free text comments. From the analysis conducted so far, a clear link appears to be present between students’ free comments and the numerical scores selected by students. There is a clear trend in the types of comments and phrases used when comparing positive and negative feedback. This trend provides confidence in the validity of the survey scores as a useful feedback mechanism. General areas for feedback have also been identified and extracted from the data. This can be applied on a subject by subject basis, or used at the whole-of-institution level