Analytical simulation of weld effects in creep range

The inelastic analysis procedure used to investigate the effect of welding on the creep rupture strength of a typical Liquid Metal Fast Breeder Reactor (LMFBR) nozzle is discussed. The current study is part of an overall experimental and analytical investigation to verify the inelastic analysis procedure now being used to design LMFBR structural components operating at elevated temperatures. Two important weld effects included in the numerical analysis are: (1) the residual stress introduced in the fabrication process; and (2) the time-independent and the time-dependent material property variations. Finite element inelastic analysis was performed on a CRAY-1S computer using the ABAQUS program with the constitutive equations developed for the design of LMFBR structural components. The predicted peak weld residual stresses relax by as much as 40% during elevated temperature operation, and their effect on creep-rupture cracking of the nozzle is considered of secondary importance

Tests on puddle and fillet weld connections

INTRODUCTION The purpose of the present investigation has been to study the behavior of symmetrically welded connections having different weld configurations. As shown in Fig. la, the specimens were fabricated by butting two plates (CP) which were connected by welding cover plates AB and CD on two sides of CP. The fabricator supplied different types of welded connection specimens, sketched in Figs. la to If. A total of 115 specimens were tested in tension under monotonically increasing static load. Basic variables considered in the design were: (a) thickness and the shape of the cover plates, and (b) weld size and its configuration. The cover plates were either flat sheet steel or channel sections. Three different thicknesses considered for the cover plates were 12 gage (0.108 inch), 18 gage (0.051 inch) galvanized ASTM A446 Grade A steel, and 28 gage (0.018 inch) galvanized ASTM A446 Grade E steel. Two basic weld configurations investigated were: (a) Puddle Welds, and (b) Fillet Welds. Varying the cover plate and weld configurations, 35 different types of connection specimens were fabricated for the present investigation. Most of the specimens had two 7/16 thick hot rolled plates CP, which were not considered as variables in the design of connection specimens. These plates were given a red oxide primer coat before welding cover plates on it. The connected plates (CP) were stronger than the cover plates, AB and CD, hence the connection failure was expected to be in the weld or in the cover plates. Therefore, in the subsequent discussion, plate failure will imply cover plate failure. Other researchers had indicated that it is difficult to weld a galvanized steel plate; therefore in this investigation, galvanized steel cover plates were used instead of regular painted steel. However, no weld defects were observed in the connection specimens

Influence of ductility on the structural behavior of light-gage cold-formed steel members

Ductility parameters defined in the second progress report were previously obtained by conducting tension coupon tests on specially produced A and S steels. In this report, tension coupon test results are presented for a 20 gage commercial low ductility steel, i.e. an ASTM Grade E steel, herein designated as steel B. Its behavior is compared with that of the specially rolled A and S steels to test the validity of conclusions arrived at in the second progress report. Test programs were set up to study the behavior of B steel under static tension loading, one program for single bolted connections and another for rectangular plates with holes. Here again the behavior of B steel is compared with A and S steels. A few connection tests were conducted on fully annealed A steel specimens to compare their behavior with low ductility A steel specimens. In Appendix B the processing and metallurgical history for A, B and S steels is given

Long Covid symptoms and diagnosis in primary care: A cohort study using structured and unstructured data in The Health Improvement Network primary care database

BACKGROUND: Long Covid is a widely recognised consequence of COVID-19 infection, but little is known about the burden of symptoms that patients present with in primary care, as these are typically recorded only in free text clinical notes. AIMS: To compare symptoms in patients with and without a history of COVID-19, and investigate symptoms associated with a Long Covid diagnosis. METHODS: We used primary care electronic health record data until the end of December 2020 from The Health Improvement Network (THIN), a Cegedim database. We included adults registered with participating practices in England, Scotland or Wales. We extracted information about 89 symptoms and 'Long Covid' diagnoses from free text using natural language processing. We calculated hazard ratios (adjusted for age, sex, baseline medical conditions and prior symptoms) for each symptom from 12 weeks after the COVID-19 diagnosis. RESULTS: We compared 11,015 patients with confirmed COVID-19 and 18,098 unexposed controls. Only 20% of symptom records were coded, with 80% in free text. A wide range of symptoms were associated with COVID-19 at least 12 weeks post-infection, with strongest associations for fatigue (adjusted hazard ratio (aHR) 3.46, 95% confidence interval (CI) 2.87, 4.17), shortness of breath (aHR 2.89, 95% CI 2.48, 3.36), palpitations (aHR 2.59, 95% CI 1.86, 3.60), and phlegm (aHR 2.43, 95% CI 1.65, 3.59). However, a limited subset of symptoms were recorded within 7 days prior to a Long Covid diagnosis in more than 20% of cases: shortness of breath, chest pain, pain, fatigue, cough, and anxiety / depression. CONCLUSIONS: Numerous symptoms are reported to primary care at least 12 weeks after COVID-19 infection, but only a subset are commonly associated with a GP diagnosis of Long Covid

Recommended practices in elevated temperature design: A compendium of breeder reactor experiences (1970-1986): An overview

Significant experiences have been accumulated in the establishment of design methods and criteria applicable to the design of Liquid Metal Fast Breeder Reactor (LMFBR) components. The Subcommittee of the Elevated Temperature Design under the Pressure Vessel Research Council (PVRC) has undertaken to collect, on an international basis, design experience gained, and the lessons learned, to provide guidelines for next generation advanced reactor designs. This paper shall present an overview and describe the highlights of the work

Multifrequency Photo-polarimetric WEBT Observation Campaign on the Blazar S5 0716+714: Source Microvariability and Search for Characteristic Timescales

Here we report on the results of the WEBT photo-polarimetric campaign targeting the blazar S5~0716+71, organized in March 2014 to monitor the source simultaneously in BVRI and near IR filters. The campaign resulted in an unprecedented dataset spanning $\sim 110$\,h of nearly continuous, multi-band observations, including two sets of densely sampled polarimetric data mainly in R filter. During the campaign, the source displayed pronounced variability with peak-to-peak variations of about $30\%$ and "bluer-when-brighter" spectral evolution, consisting of a day-timescale modulation with superimposed hourlong microflares characterized by $\sim 0.1$\,mag flux changes. We performed an in-depth search for quasi-periodicities in the source light curve; hints for the presence of oscillations on timescales of $\sim 3$\,h and $\sim 5$\,h do not represent highly significant departures from a pure red-noise power spectrum. We observed that, at a certain configuration of the optical polarization angle relative to the positional angle of the innermost radio jet in the source, changes in the polarization degree led the total flux variability by about 2\,h; meanwhile, when the relative configuration of the polarization and jet angles altered, no such lag could be noted. The microflaring events, when analyzed as separate pulse emission components, were found to be characterized by a very high polarization degree ($> 30\%$) and polarization angles which differed substantially from the polarization angle of the underlying background component, or from the radio jet positional angle. We discuss the results in the general context of blazar emission and energy dissipation models.Comment: 16 pages, 17 Figures; ApJ accepte

The 72-Hour WEBT Microvariability Observation of Blazar S5 0716+714 in 2009

Context. The international whole earth blazar telescope (WEBT) consortium planned and carried out three days of intensive micro-variability observations of S5 0716+714 from February 22, 2009 to February 25, 2009. This object was chosen due to its bright apparent magnitude range, its high declination, and its very large duty cycle for micro-variations. Aims. We report here on the long continuous optical micro-variability light curve of 0716+714 obtained during the multi-site observing campaign during which the Blazar showed almost constant variability over a 0.5 magnitude range. The resulting light curve is presented here for the first time. Observations from participating observatories were corrected for instrumental differences and combined to construct the overall smoothed light curve. Methods. Thirty-six observatories in sixteen countries participated in this continuous monitoring program and twenty of them submitted data for compilation into a continuous light curve. The light curve was analyzed using several techniques including Fourier transform, Wavelet and noise analysis techniques. Those results led us to model the light curve by attributing the variations to a series of synchrotron pulses. Results. We have interpreted the observed microvariations in this extended light curve in terms of a new model consisting of individual stochastic pulses due to cells in a turbulent jet which are energized by a passing shock and cool by means of synchrotron emission. We obtained an excellent fit to the 72-hour light curve with the synchrotron pulse model

When does NICE recommend the use of health technologies within a programme of evidence development?

This article is made available through the Brunel Open Access Publishing Fund. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.This article has been made available through the Brunel Open Access Publishing Fund.Background: There is growing interest internationally in linking reimbursement decisions with recommendations for further research. In the UK, the National Institute for Health and Clinical Excellence (NICE) can issue guidance to approve the routine use of a health intervention, reject routine use or recommend use within a research programme. These latter recommendations have restricted use to ‘only in research’ (OIR) or have recommended further research alongside routine use (‘approval with research’ or AWR). However, it is not currently clear when such recommendations are likely to be made. Objectives: This study aims to identify NICE technology appraisals where OIR or AWR recommendations were made and to examine the key considerations that led to those decisions. Methods: Draft and final guidance including OIR/AWR recommendations were identified. The documents were reviewed to establish the characteristics of the technology appraisal, the cost effectiveness of the technologies, the key considerations that led to the recommendations and the types of research required. Results: In total, 29 final and 31 draft guidance documents included OIR/AWR recommendations up to January 2010. Overall, 86 % of final guidance included OIR recommendations. Of these, the majority were for technologies considered to be cost ineffective (83 %) and the majority of final guidance (66 %) specified the need for further evidence on relative effectiveness. The use of OIR/AWR recommendations is decreasing over time and they have rarely been used in appraisals conducted through the single technology appraisal process. Conclusion: NICE has used its ability to recommend technologies within research programmes, although predominantly within the multiple technology appraisal process. OIR recommendations have been most frequently issued for technologies considered cost ineffective and the most frequently cited consideration is uncertainty related to relative effectiveness. Key considerations cited for most AWR recommendations and some OIR recommendations included a need for further evidence on long-term outcomes and adverse effects of treatment.Medical Research Counci

An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types