Ammonia from steelworks

Ammonia has been produced over the last centuries in several ways, with the Haber–Bosch process leading current production due to its efficiency and feasible deployment. However, previous to the leading positioning of the Haber–Bosch process, ammonia used to be manufactured using coal-based gas works. Coke, a remnant of the process, has been widely used for steel production processes, thus making reasonable the integration of these gas facilities into the production of steel for better economic profiles. Although this ammonia production process is currently used only in a minor share of the total ammonia market, there are locations where it is still employed to obtain the chemical for fertilizing applications. This chapter is dedicated to the production of ammonia from such steelworks, detailing some of the history, fundamental and current trends behind the process that set the foundations of ammonia as one of the main global chemicals. Steel, which will still be produced over decades, can indirectly provide a chemical that supports a more sustainable agenda if better process integration is achieved, minimizing emissions and energy losses

Influence of stabilisers on the unconfined compressive strength of a fine soil

In foundation engineering, weak subgrade soils are usually improved by adding several stabilisers to satisfy construction requirements, but the influence degree of each stabiliser on the strength of the stabilised soils is rarely studied. In this study, a series of unconfined compressive strength tests was conducted on a fine soil stabilised with various proportions of cement, lime, fly ash and gypsum. The influences of the four stabilisers were investigated through quantitative analysis and grey correlation analysis. The quantitative analysis examined the trends of the unconfined compressive strength with increasing contents of different stabilisers. It was found that there existed optimum fly ash and gypsum contents in this study. Also, the cement had the highest positive impact on the unconfined compressive strength. In the grey relational analysis, different normalisation methods were utilised, and it was found that the normalisation method and the trend of the strength with rising stabiliser content affected the order of the impact of various stabilisers. The grey relational analysis with a range-normalisation method provided a reasonable order of impact in this study

Studies of new Higgs boson interactions through nonresonant HH production in the b¯bγγ fnal state in pp collisions at √s = 13 TeV with the ATLAS detector

A search for nonresonant Higgs boson pair production in the b ¯bγγ fnal state is performed using 140 fb−1 of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. This analysis supersedes and expands upon the previous nonresonant ATLAS results in this fnal state based on the same data sample. The analysis strategy is optimised to probe anomalous values not only of the Higgs (H) boson self-coupling modifer κλ but also of the quartic HHV V (V = W, Z) coupling modifer κ2V . No signifcant excess above the expected background from Standard Model processes is observed. An observed upper limit µHH < 4.0 is set at 95% confdence level on the Higgs boson pair production cross-section normalised to its Standard Model prediction. The 95% confdence intervals for the coupling modifers are −1.4 < κλ < 6.9 and −0.5 < κ2V < 2.7, assuming all other Higgs boson couplings except the one under study are fxed to the Standard Model predictions. The results are interpreted in the Standard Model efective feld theory and Higgs efective feld theory frameworks in terms of constraints on the couplings of anomalous Higgs boson (self-)interactions

Search for non-resonant Higgs boson pair production in the 2b+2l+ETmiss final state in pp collisions at s = 13 TeV with the ATLAS detector

A search for non-resonant Higgs boson pair (HH) production is presented, in which one of the Higgs bosons decays to a b-quark pair (bb ̄) and the other decays to WW*, ZZ*, or τ+τ−, with in each case a final state with l+l−+ neutrinos (l = e, μ). The analysis targets separately the gluon-gluon fusion and vector boson fusion production modes. Data recorded by the ATLAS detector in proton-proton collisions at a centre-of-mass energy of 13 TeV at the Large Hadron Collider, corresponding to an integrated luminosity of 140 fb−1, are used in this analysis. Events are selected to have exactly two b-tagged jets and two leptons with opposite electric charge and missing transverse momentum in the final state. These events are classified using multivariate analysis algorithms to separate the HH events from other Standard Model processes. No evidence of the signal is found. The observed (expected) upper limit on the cross-section for non-resonant Higgs boson pair production is determined to be 9.7 (16.2) times the Standard Model prediction at 95% confidence level. The Higgs boson self-interaction coupling parameter κλ and the quadrilinear coupling parameter κ2V are each separately constrained by this analysis to be within the ranges [−6.2, 13.3] and [−0.17, 2.4], respectively, at 95% confidence level, when all other parameters are fixed

Electron and photon energy calibration with the ATLAS detector using LHC Run 2 data

This paper presents the electron and photon energy calibration obtained with the ATLAS detector using 140 fb−1 of LHC proton-proton collision data recorded at root(s) = 13 TeV between 2015 and 2018. Methods for the measurement of electron and photon energies are outlined, along with the current knowledge of the passive material in front of the ATLAS electromagnetic calorimeter. The energy calibration steps are discussed in detail, with emphasis on the improvements introduced in this paper. The absolute energy scale is set using a large sample of Z-boson decays into electron-positron pairs, and its residual dependence on the electron energy is used for the first time to further constrain systematic uncertainties. The achieved calibration uncertainties are typically 0.05% for electrons from resonant Z-boson decays, 0.4% at ET tilde 10 GeV, and 0.3% at ET tilde 1 TeV; for photons at ET tilde 60 GeV, they are 0.2% on average. This is more than twice as precise as the previous calibration. The new energy calibration is validated using J/psi -> ee and radiative Z-boson decays