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Objectives: Year-to-year variation in respiratory viruses may result in lower attack rates than expected. We aimed to illustrate the impact of year-to-year variation in attack rates on the likelihood of demonstrating vaccine efficacy (VE).Study Design and Setting: We considered an individually randomized maternal vaccine trial against respiratory syncytial virus (RSV)-associated hospitalizations. For 10 RSV-associated hospitalizations per 1,000 infants, sample size to have 80% power for true VE of 50% and 70% was 9,846 and 4,424 participants. We reported power to show VE for varying attack rates, selected to reflect realistic year-to-year variation using observational studies. Eight scenarios including varying number of countries and seasons were developed to assess the influence of these trial parameters.Results: Including up to three seasons decreased the width of the interquartile range for power. Including more seasons concentrated statistical power closer to 80%. Least powered trials had higher statistical power with more seasons. In all scenarios, at least half of the trials had Conclusion: Year-to-year variation in RSV attack rates should be accounted for during trial design. Mitigation strategies include recruiting over more seasons, or adaptive trial designs.

We aim to help improve the quality of life of people with visual disabilities through the application of emerging technologies. Our current research investigates the viability of virtual reality (VR) as an aid for persons with visual disabilities. In this article, we explore the potential of VR-assisted reading. We investigate the reading effects of VR equipment on persons with visual disabilities by utilising variations of standardised optometry-informed reading tests conducted across 24 participants. Test results uncovered that, when comparing a worn VR head-mounted display (HMD) to physical unaided tests, results within a HMD scaled better at closer distances, while unaided tests scaled better with further distances. Using the findings collected and requirements elicited from participants, a prototype document reader was developed for reading text within a VR-immersed 3D environment, allowing low-vision users to customise and configure accessibility features for enhanced reading. This software was tested with 11 new participants alongside user evaluations, allowing us to discover how users perceived text best within our 3D virtual environments, and what features and techniques are required to evolve this accessibility tool further. The user test reported an overwhelmingly positive response to our tool as a feasible reading aid, allowing persons who could not engage (or, due to the difficulty, refusing to) in the reading of material to do so. We also register some limitations and areas for improvement, such as a need for non-functional requirements to be improved, and the aesthetics of our design to be improved going forward.

Purpose The COVID-19 pandemic emphasises the need for antiviral materials that can reduce airborne and surface-based virus transmission. This study aims to propose the use of additive manufacturing (AM) and surrogate modelling for the rapid development and deployment of novel copper-tungsten-silver (Cu-W-Ag) microporous architecture that shows strong antiviral behaviour against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Design/methodology/approach The research combines selective laser melting (SLM), in-situ alloying and surrogate modelling to conceive the antiviral Cu-W-Ag architecture. The approach is shown to be suitable for redistributed manufacturing by representing the pore morphology through a surrogate model that parametrically manipulates the SLM process parameters: hatch distance (h_d), scan speed (S_s) and laser power (L_p). The method drastically simplifies the three-dimensional (3D) printing of microporous materials by requiring only global geometrical dimensions solving current bottlenecks associated with high computed aided design data transfer required for the AM of porous materials. Findings The surrogate model developed in this study achieved an optimum parametric combination that resulted in microporous Cu-W-Ag with average pore sizes of 80 µm. Subsequent antiviral evaluation of the optimum architecture showed 100% viral inactivation within 5 h against a biosafe enveloped ribonucleic acid viral model of SARS-CoV-2. Research limitations/implications The Cu-W-Ag architecture is suitable for redistributed manufacturing and can help reduce surface contamination of SARS-CoV-2. Nevertheless, further optimisation may improve the virus inactivation time. Practical implications The study was extended to demonstrate an open-source 3D printed Cu-W-Ag antiviral mask filter prototype. Social implications The evolving nature of the COVID-19 pandemic brings new and unpredictable challenges where redistributed manufacturing of 3D printed antiviral materials can achieve rapid solutions. Originality/value The papers present for the first time a methodology to digitally conceive and print-on-demand a novel Cu-W-Ag alloy that shows high antiviral behaviour against SARS-CoV-2.

The direct numerical simulation database from Shin et al. (J. Fluid Mech., vol. 823, 2017, pp. 1–25) is used to study three-dimensional vortical and very-large-scale coherent structures in a turbulent round jet at a Reynolds number of $7300$ . In particular, horseshoe vortices and their role in the formation of very-large-scale coherent structures in the jet near and intermediate fields are assessed. The swirling strength criterion together with conditional averaging are used to visualize volumetric vortical structures. It is shown that, similar to wall-bounded turbulent flows, the turbulent jet is populated with symmetric and asymmetric horseshoe-like vortices, which induce high-momentum and low-momentum regions in the flow. However, unlike what is found for wall-bounded flows, inverse horseshoe-like vortices are common in the turbulent jet. They prevail in the shear region around the potential core in the jet near field and contribute to the mixing of the potential core in the jet. In the jet near field, groups of axially aligned horseshoe structures induce long streaky structures, which are periodic in the azimuthal and streamwise directions. In the jet intermediate field, very-large-scale motions (VLSMs) consisting of high-momentum regions, flanked on either side by low-momentum regions, are found to be associated with groups of horseshoe vortices. Instantaneous three-dimensional flow fields suggest that horseshoe vortices tend to concatenate and form organized spiral as well as axially aligned coherent VLSMs. A detection scheme is introduced to identify and average over these VLSMs. This conditional averaging reveals that spiral VLSMs and axially aligned VLSMs constitute $72\,\%$ and $28\,\%$ of the total VLSMs, respectively.

Contains fulltext : 286832.pdf (Publisher’s version ) (Open Access) BACKGROUND: Direct evaluation of vascular inflammation in patients with COVID-19 would facilitate more efficient trials of new treatments and identify patients at risk of long-term complications who might respond to treatment. We aimed to develop a novel artificial intelligence (AI)-assisted image analysis platform that quantifies cytokine-driven vascular inflammation from routine CT angiograms, and sought to validate its prognostic value in COVID-19. METHODS: For this prospective outcomes validation study, we developed a radiotranscriptomic platform that uses RNA sequencing data from human internal mammary artery biopsies to develop novel radiomic signatures of vascular inflammation from CT angiography images. We then used this platform to train a radiotranscriptomic signature (C19-RS), derived from the perivascular space around the aorta and the internal mammary artery, to best describe cytokine-driven vascular inflammation. The prognostic value of C19-RS was validated externally in 435 patients (331 from study arm 3 and 104 from study arm 4) admitted to hospital with or without COVID-19, undergoing clinically indicated pulmonary CT angiography, in three UK National Health Service (NHS) trusts (Oxford, Leicester, and Bath). We evaluated the diagnostic and prognostic value of C19-RS for death in hospital due to COVID-19, did sensitivity analyses based on dexamethasone treatment, and investigated the correlation of C19-RS with systemic transcriptomic changes. FINDINGS: Patients with COVID-19 had higher C19-RS than those without (adjusted odds ratio [OR] 2·97 [95% CI 1·43-6·27], p=0·0038), and those infected with the B.1.1.7 (alpha) SARS-CoV-2 variant had higher C19-RS values than those infected with the wild-type SARS-CoV-2 variant (adjusted OR 1·89 [95% CI 1·17-3·20] per SD, p=0·012). C19-RS had prognostic value for in-hospital mortality in COVID-19 in two testing cohorts (high [≥6·99] vs low [

Background Ongoing outbreaks of coronavirus disease 2019 (COVID-19) are driven by waning immunity following primary immunizations and emergence of new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants that escape vaccine-induced neutralizing antibodies. It has been suggested that heterologous boosters could enhance and potentially maintain population immunity. Methods We assessed the immunogenicity and reactogenicity of booster doses of different formulations of aluminium hydroxide–adjuvanted SCB-2019 vaccine (9 μg of SCB-2019, with or without CpG-1018 adjuvant, or 30 μg of SCB-2019 with CpG-1018) in Brazilian adults primed with ChAdOx1-S vector vaccine. S-protein antibodies and ACE2-binding inhibition were measured by enzyme-linked immunosorbent assay (ELISA) on days 1, 15, and 29. Participants self-reported solicited adverse events and reactions. Results All SCB-2019 formulations increased S-protein ELISA antibodies and ACE2 binding inhibition to a greater extent than ChAdOx1-S. After 30 μg of SCB-2019 + CpG + aluminium hydroxide, titers against wild-type S-protein were significantly higher than after ChAdOx1-S on days 15 and 29, as were titers of neutralizing antibodies against the wild-type strain and Beta, Gamma, Delta, and Omicron variants. Boosting with SCB-2019 or ChAdOx1-S was well tolerated, with no vaccine-related serious or severe adverse events. Conclusions Boosting ChAdOx1-S-primed adults with SCB-2019 induced higher levels of antibodies against a wild-type strain and SARS-CoV-2 variants than a homologous ChAdOx1-S booster, with the highest responses being with the 30-μg SCB-2019 + CpG + aluminium hydroxide formulation. Clinical Trials Registration NCT05087368

BackgroundOngoing outbreaks of COVID-19 are driven by waning immunity following primary immunizations and emergence of new SARS-CoV-2 variants which escape vaccine-induced neutralizing antibodies. It has been suggested that heterologous boosters could enhance and potentially maintain population immunity.MethodsWe assessed immunogenicity and reactogenicity of booster doses of different formulations of alum-adjuvanted SCB-2019 vaccine (9 μg SCB-2019 with or without CpG-1018 adjuvant, or 30 μg SCB-2019 with CpG-1018) in Brazilian adults primed with ChAdOx1-S vector vaccine. S-protein antibodies and ACE2-binding inhibition were measured by ELISA on Days 1, 15 and 29. Participants self-reported solicited adverse events and reactions.ResultsAll SCB-2019 formulations increased S-protein ELISA antibodies and ACE2 binding inhibition to a greater extent than ChAdOx1-S. After 30 μg SCB-2019+CpG+alum titers against wild-type S-protein were significantly higher than after ChAdOx1-S on Days 15 and 29, as were titers of neutralizing antibodies against wild-type strain and Beta, Gamma, Delta, and Omicron variants. Boosting with SCB-2019 or ChAdOx1-S was well tolerated with no vaccine-related serious or severe adverse events.ConclusionsBoosting ChAdOx1-S-primed adults with SCB-2019 induced higher levels of antibodies against a wild-type strain and SARS-CoV-2 variants than a homologous ChAdOx1-S booster, highest responses being with the 30 μg SCB-2019+CpG+alum formulation.

Introduction Brazil has been at the core of the COVID-19 pandemic, with the second-highest death toll worldwide. A mass vaccination campaign was initiated on May 16th, 2021, in Botucatu, Brazil, where two doses of ChadOx1-nCoV19 were offered 12 weeks apart to all 18–60- year-olds. This context offers a unique opportunity to study the vaccine safety during a mass campaign. Methods The first and second doses of the vaccine were administered in May and August 2021, respectively. Emergency room (ER) and hospitalization records were obtained from the Hospital das Clínicas da Faculdade de Medicina de Botucatu for six weeks before and six weeks after the first and second doses, from 4 April to 19 September 2021. Diagnoses with COVID-19-related ICD codes were excluded to distinguish any trends resulting from the COVID-19 pandemic. ER and hospital visits during the two time periods were compared, including an ICD code comparison, to identify any changes in disease distributions. Data were scanned for a defined list of Adverse Events of Special Interest (AESIs), as presented by the Safety Platform for Emergency Vaccines. Results and discussion A total of 77,683 and 74,051 subjects received dose 1 and dose 2 of ChadOx1-nCoV19, respectively. Vaccination was well tolerated and not associated with any major safety concerns. Increases in ER visits 1 week following both doses were primarily seen in ICD codes related to non-serious side effects of the vaccine, including vaccination site pain and other local events. The neurological AESIs identified (2 of 3 cases of multiple sclerosis) were relapses of a pre-existing condition. One potentially serious hospitalization event for Bell’s palsy had onset before vaccination with dose 1, in a patient who also had a viral infection of the central nervous system. There was no myocarditis, pericarditis cases, or vaccine-related increases in thromboembolic events.

Background: Digital biomarkers that measure physical activity and mobility are of great interest in the assessment of chronic diseases such as rheumatoid arthritis, as it provides insights on patients’ quality of life that can be reliably compared across a whole population. Objective: To investigate the feasibility of analyzing iPhone sensor data collected remotely by means of a mobile software application in order to derive meaningful information on functional ability in rheumatoid arthritis patients. Methods: Two objective, active tasks were made available to the study participants: a wrist joint motion test and a walk test, both performed remotely and without any medical supervision. During these tasks, gyroscope and accelerometer time-series data were captured. Processing schemes were developed using machine learning techniques such as logistic regression as well as explicitly programmed algorithms to assess data quality in both tasks. Motion-specific features including wrist joint range of motion (ROM) in flexion-extension (for the wrist motion test) and gait parameters (for the walk test) were extracted from high quality data and compared with subjective pain and mobility parameters, separately captured via the application. Results: Out of 646 wrist joint motion samples collected, 289 (45%) were high quality. Data collected for the walk test included 2,583 samples (through 867 executions of the test) from which 651 (25%) were high quality. Further analysis of high-quality data highlighted links between reduced mobility and increased symptom severity. ANOVA testing showed statistically significant differences in wrist joint ROM between groups with light-moderate (220 participants) versus severe (36 participants) wrist pain (p < 0.001) as well as in average step times between groups with slight versus moderate problems walking about (p < 0.03). Conclusion: These findings demonstrate the potential to capture and quantify meaningful objective clinical information remotely using iPhone sensors and represent an early step towards the development of patient-centric digital endpoints for clinical trials in rheumatoid arthritis.

Over a remarkably productive professional life Brian Spalding largely shaped the development of numerical procedures for computing complex turbulent flows. He created a major software company, CHAM, through which the fruits of his group's research could be made available to industry and other research groups across the globe. Thus, he became the outstanding founding figure in the subject now called computational fluid dynamics (CFD). His contributions were by no means limited to strategies for converting systems of non-linear partial differential equations to forms suitable for computer solution; he also brought notable innovations to the physical modelling of combustion, turbulence and two-phase flows. Besides research, he engaged deeply with the research community in heat and mass transfer, becoming a founding editor of two international journals in these areas, and a principal driver behind the creation of the International Centre for Heat and Mass Transfer in Belgrade. He also served as the inaugural scientific chairman of the European Research Community on Flow, Turbulence and Combustion. He led a protracted and ultimately successful campaign to enable Veniamin Levich to leave the Soviet Union to settle in Israel. Outside of his technical work, his principal passions were poetry and the Russian language, which were intertwined in several published volumes.

Coherent structures in turbulent round jets are evaluated for a jet Reynolds number up to in the axial, radial and azimuthal directions is observed. The other spectral domain, indicated by large wavelengths, is associated with very-large-scale motions (VLSMs). The wavelength marking the boundary between these spectral domains is used to decompose the velocity fluctuations into ES and VLSM components, and the corresponding ES and VLSM components of two-point correlations are obtained from the experimental data. The VLSM component of two-point correlations denotes helical structures as the dominant VLSMs in the jet turbulent region. Instantaneous axial velocity fluctuation fields from DNS support the prevalence of helical VLSMs in the jet. Moreover, the ES signatures are evident in the unwrapped axial–azimuthal planes of the DNS, indicating that the VLSMs are formed by the concatenation of ESs. Consistent with the experimental two-point correlations and DNS flow fields, a conceptual model is proposed for the ESs and VLSMs, which illustrates their arrangements.

Background: COVID-19 vaccine supply shortages are causing concerns about compromised immunity in some countries as the interval between first and second dose extends. Conversely, countries with no supply constraints are considering administering a third dose. We assessed the persistence of immunogenicity after a single dose, the immunity after an extended interval between the first and second dose of ChAdOx1 nCoV-19(AZD1222), and the response to a third dose as a late booster. Methods: Volunteers aged 18-55 years who were enrolled in a Phase 1/2 or Phase 2/3 clinical trial of ChAdOx1 nCoV-19 and had received either a single dose or two doses of 5×10 10 viral particles were invited back for vaccination. Reactogenicity and immunogenicity of a delayed second dose or a third dose are reported here. Findings: Antibody titres after a single dose and measured on d362 remain higher than the titres measured on d0 (62.61 EU; 95% CI 47.43-82.64 vs 1 EU 95% CI 1-16). 30 participants received a late second dose of ChAdOx1 nCoV-19 (median 44 weeks after first dose), antibody titres were higher in those with a longer interval between first and second dose (median EU for 8-12, 15-25, and 44-46 weeks were 923 [IQR 525-1764], 1860 [IQR 917-4934] and 3738 [IQR 1824-6625] respectively). 90 participants received a third dose and antibody titres were significantly higher following a third dose (FRNT50 612 [IQR 351-920]) when compared with the response 28 days after a second dose (FRNT 50 319 [IQR 176-591]. T-cell responses were also boosted after a third dose. Reactogenicity after a late second dose or a third dose was lower than reactogenicity after a first dose. Interpretation: A longer delay before the second dose of ChAdOx1 nCoV-19 leads to an increased antibody titre after the second dose. A third dose of ChAdOx1 nCoV-19 induces antibodies to a level that correlate with high efficacy after second dose and boosts T-cell responses. Funding: UK Research and Innovation (MC_PC_19055), Engineering and Physical Sciences Research Council (EP/R013756/1), National Institute for Health Research (COV19 OxfordVacc-01), Coalition for Epidemic Preparedness Innovations (Outbreak Response To Novel Coronavirus (COVID-19)), National Institute for Health Research Oxford Biomedical Research Centre (BRC4 Vaccines Theme), Thames Valley and South Midland’s NIHR Clinical Research Network, and AstraZeneca. The views expressed in this publication are those of the authors and not necessarily those of the NIHR or the UK Department of Health and Social Care. Declaration of Interest: Oxford University has entered into a partnership with AstraZeneca for further development of ChAdOx1 nCoV-19. AstraZeneca reviewed the data from the study and the final manuscript before submission, but the authors retained editorial control. SCG and AVSH are cofounders of and shareholders in Vaccitech (collaborators in the early development of this vaccine candidate) and named as inventors on a patent covering use of ChAdOx1-vectored vaccines (PCT/GB2012/000467) and a patent application covering this SARS-CoV-2 vaccine (SCG only). TL is named as an inventor on a patent covering use of ChAdOx1-vectored vaccines (PCT/GB2012/000467) and was a consultant to Vaccitech. PMF is a consultant to Vaccitech. AJP is Chair of the UK Department of Health and Social Care’s JCVI, but does not participate in policy advice on coronavirus vaccines, and is a member of the WHO Strategic Advisory Group of Experts (SAGE). AJP is a NIHR Senior Investigator. Ethical Approval: In the UK, the COV001 and COV002 studies were approved by the South Central Berkshire Research Ethics Committee (COV001 reference 20/SC/0145, March 23, 2020; and COV002 reference 20/SC/0179; conditional approval April 8, full approval April 19, 2020).

Background: The ChAdOx1 nCoV-19 (AZD1222) vaccine has been approved for emergency use by the UK regulatory authority, MHRA, with a regimen of two standard doses given with an interval of between 4 and 12 weeks. The planned rollout in the UK will involve vaccinating people in high risk categories with their first dose immediately, and delivering the second dose 12 weeks later.Here we provide both a further prespecified pooled analysis of trials of ChAdOx1 nCoV-19 and exploratory analyses of the impact on immunogenicity and efficacy of extending the interval between priming and booster doses. In addition, we show the immunogenicity and protection afforded by the first dose, before a booster dose has been offered. Methods: We present data from phase III efficacy trials of ChAdOx1 nCoV-19 in the United Kingdom and Brazil, and phase I/II clinical trials in the UK and South Africa, against symptomatic disease caused by SARS-CoV-2. The data cut-off date for these analyses was 7th December 2020. The accumulated cases of COVID-19 disease at this cut-off date exceeds the number required for a pre-specified final analysis, which is also presented. As previously described, individuals over 18 years of age were randomised 1:1 to receive two standard doses (SD) of ChAdOx1 nCoV-19 (5x1010 viral particles) or a control vaccine/saline placebo. In the UK trial efficacy cohort a subset of participants received a lower dose (LD, 2.2x1010 viral particles) of the ChAdOx1 nCoV-19 for the first dose. All cases with a nucleic acid amplification test (NAAT) were adjudicated for inclusion in the analysis, by a blinded independent endpoint review committee. Studies are registered at ISRCTN89951424 and ClinicalTrials.gov; NCT04324606, NCT04400838, and NCT04444674. Findings: 17,177 baseline seronegative trial participants were eligible for inclusion in the efficacy analysis, 8948 in the UK, 6753 in Brazil and 1476 in South Africa, with 619 documented NAAT +ve infections of which 332 met the primary endpoint of symptomatic infection >14 days post dose 2.The primary analysis of overall vaccine efficacy >14 days after the second dose including LD/SD and SD/SD groups, based on the prespecified criteria was 66.7% (57.4%, 74.0%). There were no hospitalisations in the ChAdOx1 nCoV-19 group after the initial 21 day exclusion period, and 15 in the control group.Vaccine efficacy after a single standard dose of vaccine from day 22 to day 90 post vaccination was 76% (59%, 86%), and modelled analysis indicated that protection did not wane during this initial 3 month period. Similarly, antibody levels were maintained during this period with minimal waning by day 90 day (GMR 0.66, 95% CI 0.59, 0.74).In the SD/SD group, after the second dose, efficacy was higher with a longer prime-boost interval: VE 82.4% 95%CI 62.7%, 91.7% at 12+ weeks, compared with VE 54.9%, 95%CI 32.7%, 69.7% at

Background: A new variant of SARS-CoV-2, B.1.1.7, emerged as the dominant cause of COVID-19infection in the United Kingdom from November 2020 with a transmission advantage over the previous variants of the virus. Here we report efficacy of the adenoviral vector vaccine, ChAdOx1 nCoV-19, against this variant in comparison with non-B.1.1.7 lineages. Methods: Volunteers enrolled in phase II/III vaccine efficacy studies in the United Kingdom and randomised 1:1 to receive ChAdOx1 nCoV-19 or a MenACWY control vaccine, providedupper airway swabs every week during the trial and also if they developed possible symptomatic COVID-19 infection. Swabs were tested by nucleic acid amplification test (NAAT) for SARS-CoV-2, and positive samples were sequenced through the COVID-19Genomics UK consortium (COG UK). NAAT data were used to assess the duration ofdetectable viral RNA in diagnostic specimens and the viral load. Anti-spike IgG wasmeasured by ELISA at baseline, 14 and 28 days after prime and 28 days after boostervaccination. Neutralising antibody responses were measured using a live virus neutralisation assay against the B.1.1.7 and Victoria lineages of the virus. The efficacy analysis included symptomatic COVID-19 in seronegative participants with a NAAT positive swab more than 14 days after a second dose of vaccine. Participants were analysed according to treatment received, with data cut-off on Jan 14, 2021. Vaccine efficacy was calculated as 1 − relative risk derived from a robust Poisson regression model. This study is ongoing and is registered with ClinicalTrials.gov NCT04400838 and ISRCTN 15281137.5 Findings: Between 1st October 2020 and 14th January 2021, 499 participants developed Covid-19infection. 1524 NAAT positive nose/throat swabs were collected from these participants during the trial. Of these, 323 swabs from 256 participants were successfully sequenced.ChAdOx1 nCoV-19 recipients had a significantly lower viral load as represented byminimum PCR Ct value (p

The turbulent round jet is considered including the effects of introducing swirl, tabs and rings so as to modify its behaviour. The paper traces the influence of Ricou and Spalding [J Fluid Mech 11(1):21–32, 1961] through almost 60 years of research into this proto-typical engineering and canonically fundamental flow, albeit from a personal perspective. It culminates on current efforts to unravel the turbulent, non-turbulent interface and a brief examination of Spalding’s population modelling ideas, which could assist exploration of this fascinating multi-scale flow.

This work characterizes the local dissipation length-scale η and its related quantities in turbulent (round and square) jets. It is revealed that the probability density function (PDF) of η, denoted by Q(η), displays different shapes in the jet’s central region and shear layer. In the central jet of full turbulence, the distribution of Q(η) is insensitive to changes in the initial flow conditions and the degree of anisotropy, and agrees well with those obtained previously from a pipe flow and DNS of a box turbulence. On the other hand, the left tail of Q(η) at small η rises with increasing lateral distance from the centerline (toward the jet outer region), where the turbulent/non-turbulent intermittency occurs due to jet engulfment of ambient fluid; such large-scale intermittency is expected to enhance fine-scale dissipation intermittency. Therefore, the present work demonstrates that the smallest-scale dissipation fluctuations behave universally as in fully turbulent flows, irrespective of the flow type; but this universality is broken in partially turbulent flows or in flow regions where large-scale intermittency emerges.

Experimental results on the near field development of a turbulent rectangular wall jet with aspect ratio 10 that issues from a sharp-edged orifice at Re h ∼ 23,000 are presented and discussed, in comparison with results obtained in a free jet with identical initial conditions. Hot wire X-probe measurements on cross plane grids provide information on the 3D characteristics of the flow field. This work, besides presenting the main features of the jet, focuses on the effect of vorticity on the development of specific flow field characteristics. Mean vorticity components were estimated by interpolation and derivation from the mean and turbulent velocity measurements and the symmetries of the flow field were imposed by suitable averaging. Several terms of the axial vorticity equation are presented and discussed to uncover some complex flow physics, related e.g. to axis switching and the formation of a dumbbell shape of the jet outline, in the early stages of development.

Three-dimensional (3D) hydrostatic and nonhydrostatic versions of the MITgcm were applied to simulate the dynamics of the internal wave field (basin-scale seiches, nonlinear surges and high-frequency nonlinear internal waves, NLIWs) in Cayuga Lake, NY. The simulations were performed using up to 226 million computational cells with several horizontal grid resolutions, varying from 450 × 450 m to 22 × 22 m. Vertical grid spacing was not varied and ranged from 0.5 m to 2.95 m. The 22 × 22 m nonhydrostatic grid reproduced qualitatively the formation, propagation and shoaling of observed NLIWs using >10 grid points along the wavelength and a grid lepticity λ of O(1). This ensured, respectively, that the waves were not aliased and physical dispersion predominated over numerical dispersion. Using a sensitivity analysis, we generalize that correctly simulating NLIWs in real domains, using second-order discretization, requires grid resolutions that are an order of magnitude smaller than the wavelength and amplitude with λ ∼ 2; consistent with published work on idealized domains. Local gyre-like circulation was simulated, near mid-basin headlands, and transverse shoaling of NLIW packets on lateral boundaries was associated with topographic reflection and refraction, in agreement with published field observations from estuaries, which show NLIW propagation in long narrow quasi-2D systems (e.g., Finger Lakes, lochs, fjords, estuaries and straits) is fundamentally 3D. These results, therefore, help fill the gap in understanding and correctly modelling the multiscale 3D dynamics of NLIWs in complex natural systems. This article is protected by copyright. All rights reserved.

The moisture content (MC) of a fuel is generally determined through gravimetric analysis where a sample is dehydrated in an oven over a period of approximately 24 h; the MC is then calculated by dividing the difference between the initial and final mass, by the initial mass. Handheld moisture meters offer the benefit of near-instantaneous measurements and should provide accurate and dependable results. The performance of nine moisture meters applied to seven low-carbon fuels (LCFs) was determined. The nine meters employed three measurement technologies: electrical conductance/resistance, electrical capacitance and electromagnetic inductance. The seven LCF samples considered were: shredded switchgrass, two batches of shredded wood, two batches of ragger tails and two batches of sanitary products. A moisture meter applicable for LCF should have a clear relationship between the actual MC and the measured MC, low variability, and be accurate within an absolute difference of 2%. Results indicated that none of the meters were suitable for use on LCF in general. It was not possible to identify a specific measurement technology that performed better for a certain LCF type from the results.