Introduction Of Confinement Research Articles

The COVID-19 alcohol paradox: British household purchases during 2020 compared with 2015-2019.

British supermarket-panel data suggest no increases in overall sales and purchases of alcohol following COVID-19 lockdowns, yet survey and mortality data suggest otherwise. This paper attempts to unravel the paradox. Based on purchase data of 79,417 British households from Kantar Worldpanel, we undertake controlled interrupted time series analysis of the impact of COVID-19 confinement introduced on 23rd March 2020, and variably applied during 2020, compared to purchases during 2015 to 2019 as controls. We also undertook Poisson regression analyses to estimate if changes in purchases differed by household socio-demographic and economic factors. Excess off-trade household alcohol purchases (expressed as grams of ethanol) following the introduction of confinement, were 29.2% higher (95% CI = 25.8% to 32.5%) for the post-confinement months of 2020, being larger until mid-July 2020 (37.5%, 95%CI = 33.9 to 41.26%) when pubs re-opened with restrictions, and smaller (24.6%, 95%CI = 21.6 to 27.7) thereafter. During the time of complete pub closures, and fully adjusting for no on-trade purchases, household purchases of alcohol did not change when compared with the same time period during 2015–2019 (coefficient = -0.9%, 95%CI = -5.6 to 3.8). Excess purchases from 23rd March to 31st December 2020 varied by region of Great Britain, being higher in the north of England, and lower in Scotland and Wales. Excess purchases were greater in the most deprived households, compared with the least deprived households. Excess purchases increased substantially as the amount of alcohol normally purchased by a household increased, with the top one fifth of households that normally bought the most alcohol increasing their purchases more than 17 times than the bottom one fifth of households that bought the least alcohol. That the heaviest buyers of alcohol increased their purchases the most, with some independent impact of socio-economic disadvantage, might explain why reported alcohol problems and recent alcohol-related death rates might have increased. A conclusion of this is that alcohol policy to reduce high consumption of alcohol, and the availability of help and treatment to reduce alcohol consumption become more important during extraordinary times, such as COVID lockdowns.

Achieving industrial ammonia synthesis rates at near-ambient conditions through modified scaling relations on a confined dual site

The production of ammonia through the Haber-Bosch process is regarded as one of the most important inventions of the 20th century. Despite significant efforts in optimizing the process, it still consumes 1 to 2% of the worldwide annual energy for the high working temperatures and pressures. The design of a catalyst with a high activity at milder conditions represents another challenge for this reaction. Herein, we combine density functional theory and microkinetic modeling to illustrate a strategy to facilitate low-temperature and -pressure ammonia synthesis through modified energy-scaling relationships using a confined dual site. Our results suggest that an ammonia synthesis rate two to three orders of magnitude higher than the commercial Ru catalyst can be achieved under the same reaction conditions with the introduction of confinement. Such strategies will open pathways for the development of catalysts for the Haber-Bosch process that can operate at milder conditions and present more economically viable alternatives to current industrial solutions.

Aerodynamic Performance of a Vibrating Piezoelectric Blade Under Varied Operational and Confinement States

This paper investigates the aerodynamic performance of a piezoelectrically actuated cantilever blade operating in the first mode of vibration. Bulk air-moving capability and local velocity field features have been experimentally measured for different operational conditions and blade confinement states. A testing facility has been developed to determine the pressure-flow rate characteristics of a vibrating blade and simultaneously conduct particle image velocimetry. Under high system resistance, similar to that found in densely packed electronics, flow reversal occurs at the blade outlet region analogous to stall. This is accompanied by increased local unsteadiness in the airflow being emitted. Local turbulence intensity increases by 50% between maximum flow rate and maximum efficiency operating points. The introduction of confinement around a vibrating blade reduces bulk air-moving capability significantly, with pressure rise and volumetric flow rate measured as low as 20% of what can be achieved for an unconfined blade. However, there is an accompanying change in spatial velocity distribution, which focuses the flow normal to the outlet. This has potentially beneficial uses for targeted electronics cooling applications. The findings identify the relationship between local and bulk airflow characteristics that ultimately provides information about the sensitivity of this type of air-moving device in practical installations.

Computer Simulation of Polymer Chains in Confinement

Properties of macromolecules confined in a narrow slit, pore or capillary are important due to of their practical importance. Theoretical treatment of such systems is also interesting because the introduction of confinement has an impact on most properties of polymer chains and it gained a longstanding attention. In order to determine the properties of such systems coarse-grained models of confined polymers were designed where macromolecules were represented by united atoms. Lattice approximation was also often introduced. Different macromolecular architectures were studied: linear, cyclic and star-branched chains. Computer simulation techniques (the variants of the Monet Carlo method like the Metropolis algorithm and the Replica Exchange method as well as Molecular Dynamics and Brownian Dynamics methods) applied for studies of such models were reviewed and evaluated. The structure of the polymer film and the dynamic properties were mainly presented and discussed. The influence of the width of the slit, the temperature and the force field on the dimension and the structure of chains were studied. It was shown that a moderate confinement stabilizes folded chains while a strong confinement does not.

Structure of polymer films in adsorbing slit: A computer simulation study

The introduction of confinement has an impact on most properties of polymer chains. A coarse-grained model of branched polymers confined in a slit formed by two parallel impenetrable surfaces which were attractive for polymer segments was developed and studied. The model chains were regular stars consisted of three branches of equal length. The positions of chains were restricted to vertices of a simple cubic lattice. The chains were at good solvent conditions and, therefore, the excluded volume was the only interaction between the segments of the chain. The properties of the model systems were determined by means of dynamic Monte Carlo simulations with a sampling algorithm based on chain's local changes of conformation. The dependence of polymer density in the slit on a structure of the macromolecular film was studied. An interesting mechanism of the chain motion – jumps between surfaces – was also shown.