The influence of hospital ward design on resilience to heat waves: An exploration using distributed lag models

Distributed lag models (DLMs) to predict future internal temperatures have been developed using the hourly weather data and the internal temperatures recorded in eleven spaces on two UK National Health Service (NHS) hospital sites. The ward spaces were in five buildings of very different type and age. In all the DLMs, the best prediction of internal temperature was obtained using three exogenous drivers, previous internal temperature, external temperature and solar radiation. DLMs were sensitive to the buildings’ differences in orientation, thermal mass and shading and were validated by comparing the predictions with the internal temperatures recorded in the summer of 2012. The results were encouraging, with both modelled and recorded data showing good correlation. To understand the resilience of the spaces to heat waves, the DLMs were fed with weather data recorded during the hot summer of 2006. The Nightingale wards and traditional masonry wards showed remarkable resilience to the hot weather. In contrast, light-weight modular buildings were predicted to overheat dangerously. By recording internal temperatures for a short period, DLMs might be created that can forecast future temperatures in many other types of naturally ventilated or mixed-mode buildings as a means of assessing overheating ris

Priority school building programme: an investigation into predicted occupant comfort during the heating season in naturally ventilated classrooms

Natural ventilation solutions can provide sufficient outside air to maintain adequate indoor air quality (IAQ), which can improve occupants’ performance in classrooms and provide reductions in energy consumption for space conditioning. In this study, the effect of cool outside air and the vent opening configurations on IAQ and occupant thermal comfort in naturally ventilated classrooms during the heating season was examined. Dynamic and steady state computer simulations were performed to investigate the internal conditions of a naturally ventilated classroom, designed to meet the requirements of the Priority Schools Building Programme (PSBP) Output Specification. The modelled designs considered natural cross ventilation airflow through high-level top hung-out or bottom hung-in openings, and a stack (atrium). Dynamic thermal modelling results indicate that adequate IAQ and occupant thermal comfort could be achieved using natural ventilation. However, the CFD simulation results predicted occupant discomfort due to draughts in the regions close to the openings. Bottom hung-in vents reduced draught impact and the study also suggests moving occupants away from the draught zones to minimise the effect of discomfort draughts on occupant comfort. The air velocity and airflow patterns in the classrooms were influenced by the shape, size, location of internal openings, and the flowrate through the openings. This could be controlled by introduction of new openings with lower airflow rates through each opening

Evaluation of thermal comfort in naturally ventilated school classrooms using CFD

This paper investigates the performance and control of natural ventilation during the heating season in order to avoid occupant discomfort. The current study examined different window configurations under a wide range of external temperatures and wind speeds using a CFD simulation tool. The results showed that thermally comfortable indoor conditions could be achieved in a UK classroom when external temperatures are as low as 8°C using high-level openable windows. At lower external temperatures, occupants are predicted to be thermally dissatisfied due to localised discomfort caused by draughts. The results from the CFD model also suggest that acceptable internal thermal conditions can be maintained with wind speeds up to 10m/s, for an external temperature of 10°C. The PMV results indicated that thermal comfort is achieved and is uniformly distributed within the classroom. This work will enable the UK’s Education Funding Agency to have a greater understanding of the effective control of windows to eliminate wintertime discomfort and avoid unnecessary heating for naturally ventilated spaces

Measurement of the VH,H → ττ process with the ATLAS detector at 13 TeV

A measurement of the Standard Model Higgs boson produced in association with a W or Z boson and decaying into a pair of τ-leptons is presented. This search is based on proton-proton collision data collected at √s = 13 TeV by the ATLAS experiment at the LHC corresponding to an integrated luminosity of 140 fb−1. For the Higgs boson candidate, only final states with at least one τ-lepton decaying hadronically (τ →hadrons + vτ ) are considered. For the vector bosons, only leptonic decay channels are considered: Z → ℓℓ and W → ℓvℓ, with ℓ = e, μ. An excess of events over the expected background is found with an observed (expected) significance of 4.2 (3.6) standard deviations, providing evidence of the Higgs boson produced in association with a vector boson and decaying into a pair of τ-leptons. The ratio of the measured cross-section to the Standard Model prediction is μττ VH = 1.28 +0.30 −0.29 (stat.) +0.25 −0.21 (syst.). This result represents the most accurate measurement of the VH(ττ) process achieved to date

Measurement of diferential cross-sections in tt¯ and tt¯+jets production in the lepton+jets fnal state in pp collisions at √s = 13 TeV using 140 fb−1 of ATLAS data

Diferential cross-sections for top-quark pair production, inclusively and in association with jets, are measured in pp collisions at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC using an integrated luminosity of 140 fb−1. The events are selected with one charged lepton (electron or muon) and at least four jets. The differential cross-sections are presented at particle level as functions of several jet observables, including angular correlations, jet transverse momenta and invariant masses of the jets in the final state, which characterise the kinematics and dynamics of the top-antitop system and the hard QCD radiation in the system with associated jets. The typical precision is 5%–15% for the absolute differential cross-sections and 2%–4% for the normalised differential cross-sections. Next-to-leading-order and next-to-next-to-leading-order QCD predictions are found to provide an adequate description of the rate and shape of the jet-angular observables. The description of the transverse momentum and invariant mass observables is improved when next-to-next-to-leading-order QCD corrections are included

The ATLAS trigger system for LHC Run 3 and trigger performance in 2022

The ATLAS trigger system is a crucial component of the ATLAS experiment at the LHC. It is responsible for selecting events in line with the ATLAS physics programme. This paper presents an overview of the changes to the trigger and data acquisition system during the second long shutdown of the LHC, and shows the performance of the trigger system and its components in the proton-proton collisions during the 2022 commissioning period as well as its expected performance in proton-proton and heavy-ion collisions for the remainder of the third LHC data-taking period (2022–2025)

Observation of quantum entanglement with top quarks at the ATLAS detector

Entanglement is a key feature of quantum mechanics with applications in fields such as metrology, cryptography, quantum information and quantum computation. It has been observed in a wide variety of systems and length scales, ranging from the microscopic to the macroscopic. However, entanglement remains largely unexplored at the highest accessible energy scales. Here we report the highest-energy observation of entanglement, in top–antitop quark events produced at the Large Hadron Collider, using a proton–proton collision dataset with a centre-of-mass energy of √s = 13 TeV and an integrated luminosity of 140 inverse femtobarns (fb)−1 recorded with the ATLAS experiment. Spin entanglement is detected from the measurement of a single observable D, inferred from the angle between the charged leptons in their parent top- and antitop-quark rest frames. The observable is measured in a narrow interval around the top–antitop quark production threshold, at which the entanglement detection is expected to be significant. It is reported in a fiducial phase space defined with stable particles to minimize the uncertainties that stem from the limitations of the Monte Carlo event generators and the parton shower model in modelling top-quark pair production. The entanglement marker is measured to be D = −0.537 ± 0.002 (stat.) ± 0.019 (syst.) for 340 GeV < mtt < 380 GeV. The observed result is more than five standard deviations from a scenario without entanglement and hence constitutes the first observation of entanglement in a pair of quarks and the highest-energy observation of entanglement so far

Simultaneous energy and mass calibration of large-radius jets with the ATLAS detector using a deep neural network

The energy and mass measurements of jets are crucial tasks for the Large Hadron Collider experiments. This paper presents a new calibration method to simultaneously calibrate these quantities for large-radius jets measured with the ATLAS detector using a deep neural network (DNN). To address the specificities of the calibration problem, special loss functions and training procedures are employed, and a complex network architecture, which includes feature annotation and residual connection layers, is used. The DNN-based calibration is compared to the standard numerical approach in an extensive series of tests. The DNN approach is found to perform significantly better in almost all of the tests and over most of the relevant kinematic phase space. In particular, it consistently improves the energy and mass resolutions, with a 30% better energy resolution obtained for transverse momenta pT > 500 GeV

Inclusive and diferential cross-section measurements of ttZ¯ production in pp collisions at √s = 13 TeV with the ATLAS detector, including EFT and spin-correlation interpretations

Measurements of both the inclusive and diferential production cross sections of a top-quark-top-antiquark pair in association with a Z boson (ttZ¯ ) are presented. Final states with two, three or four isolated leptons (electrons or muons) are targeted. The measurements use the data recorded by the ATLAS detector in pp collisions at √s = 13 TeV at the Large Hadron Collider during the years 2015–2018, corresponding to an integrated luminosity of 140 fb−1. The inclusive cross section is measured to be σttZ¯ = 0.86±0.04 (stat.)±0.04 (syst.) pb and found to be in agreement with the most advanced Standard Model predictions. The differential measurements are presented as a function of a number of observables that probe the kinematics of the ttZ¯ system. Both the absolute and normalised differential cross-section measurements are performed at particle level and parton level for specific fiducial volumes, and are compared with NLO+NNLL theoretical predictions. The results are interpreted in the framework of Standard Model effective field theory and used to set limits on a large number of dimension-6 operators involving the top quark. The first measurement of spin correlations in ttZ¯ events is presented: the results are in agreement with the Standard Model expectations, and the null hypothesis of no spin correlations is disfavoured with a significance of 1.8 standard deviations