Structure and dynamics in protic ionic liquids: a combined optical Kerr-effect and dielectric relaxation spectroscopy study

The structure and dynamics of ionic liquids (ILs) are unusual due to the strong interactions between the ions and counter ions. These microscopic properties determine the bulk transport properties critical to applications of ILs such as advanced fuel cells. The terahertz dynamics and slower relaxations of simple alkylammonium nitrate protic ionic liquids (PILs) are here studied using femtosecond optical Kerr-effect spectroscopy, dielectric relaxation spectroscopy, and terahertz time-domain spectroscopy. The observed dynamics give insight into more general liquid behaviour while comparison with glass-forming liquids reveals an underlying power-law decay and relaxation rates suggest supramolecular structure and nanoscale segregation

Dielectric relaxation of the ionic liquid 1-ethyl-3-methylimidazolium ethyl sulfate: microwave and far-IR properties

Dielectric relaxation of the ionic liquid, 1-ethyl-3-methylimidazolium ethyl sulfate (EMI+ETS–), is studied using molecular dynamics (MD) simulations. The collective dynamics of polarization arising from cations and anions are examined. Characteristics of the rovibrational and translational components of polarization dynamics are analyzed to understand their respective roles in the microwave and terahertz regions of dielectric relaxation. The MD results are compared with the experimental low-frequency spectrum of EMI+ETS–, obtained via ultrafast optical Kerr effect (OKE) measurements

Towards the electrochemical conversion of CO2 to formic acid at an applicative scale: technical and economic analysis of most promising routes

In the last decade, the electrochemical conversion of CO 2 to formic acid, FA, using Sn\u2010based cathodes, was widely investigated. In this work, the technical feasibility and economic viability of this process were evaluated considering the most promising electrochemical routes reported in the literature. Five case studies, based on the utilisation of GDE technologies or high CO 2 pressures, were analysed. The cost for producing FA by the electrochemical route was compared with that of the conventional chemical route. Several scenarios were envisioned finding the target figures of merit, the potential bottlenecks (including low FA concentration, GDE cost and high energy consumption) of each technology and the challenges that need to be faced. It was shown that the performances of these processes are not still adequate from an economic point of view and the improvements that should be achieved were identified. To be suitable for the commercialisation, the process should reach simultaneously high current density, faradaic efficiency and actual FA concentration as well as good stability with time and a limited cost of electrodes. In addition, it was shown that the utilisation of the excess electric energy generated from renewable sources could significantly reduce the costs of the process

Anaesthesia skills and simulation training during the COVID-19 pandemic

No Abstrac

GABA-B receptor function in healthy volunteers, a pharmacokinetic and pharmacodynamic study of two doses of baclofen compared to placebo

AIMS AND HYPOTHESIS To assess the subjective and objective effects of baclofen on brain function in healthy volunteers. BACKGROUND Recent evidence suggests baclofen, a γ-aminobutyric acid type B (GABA-B) receptor agonist, reduces alcohol consumption and craving and promotes abstinence in alcoholics. However, characterisation of the GABA-B receptor system in clinical addiction is limited, and it is unclear why some patients require, or tolerate, higher doses to treat alcoholism. This study assesses the effects of baclofen on brain function in healthy volunteers to inform future studies investigating the sensitivity of GABA-B receptors in alcohol addiction. METHODS Eight healthy male volunteers completed a double blind randomised 3-way cross over study, receiving oral placebo (vitamin C 100mg), 10mg and 60mg baclofen. Subjective and objective measurements were taken at baseline (before medication) and at +30mins, 1, 2, 3, 4 and 6 hours after dosing. Objective measures included blood plasma samples, heart rate and blood pressure. Subjective measures included; the Subjective High Assessment Questionnaire (SHAS), visual analogue scales for sleepy, relaxed, tense and alert and a motor coordination task (zig-zag task). Pharmacokinetic data was obtained using liquid chromatography mass-spectrometry (LC-MS) to measure plasma baclofen concentrations. RESULTS 60mg Baclofen showed changes in subjective measures peaking at 2 hours post dosing compared with placebo, including a significant increase (p<0.05) in total SHAS scores with individual items, including feeling ‘drunk or intoxicated’, effects of alcohol and ‘muddled or confused’ particular affected.. Systolic blood pressure was significantly increased (p<0.05) at the 2 hours post 60mg dose. For both 10mg and 60mg baclofen, peak plasma concentration was achieved 60 minutes post dose. Pharmacokinetic data will be presented. There were no significant changes in these measures between 10mg Baclofen and placebo. CONCLUSIONS The objective and subjective measures used in this study are able to differentiate between placebo and 60mg baclofen. These findings will inform further research investigating the sensitivity of GABA-B receptors in alcohol addiction

An analysis of the air-jet yarn texturing process. Part 4, Fluid forces acting on the filaments and the effects of filament cross-sectional area and shape

Fluid (drag) forces acting on filaments in an air-flow are theoretically analysed, and equations to calculate them are derived. Drag forces acting on filaments are shown to vary with the filament cross-section, the position of the filaments across the nozzle, and the local air velocity. Since finer filaments have a smaller inertial resistance to fluid forces and have lower stiffness, yarns with finer filaments are shown to be more suitable for air-jet texturing. Theoretical modelling of a lament as it emerges from the nozzle shows that, for filaments with identical linear densities, those with cross sections having reduced bending and torsional stiffness, such as elhpt1c cross-sections, may be more suitable for air-jet texturing

An analysis of the air-jet yarn texturing process. Part 6, The mechanism of loop formation

After a brief summary of the findings and conclusions of the previously reported investigations on the air-jet texturing process, a mechanism of loop formation is postulated. The factors affecting loop formation are analysed in the light of the mechanism described. This mechanism of loop formation is claimed to be valid for all types of texturing nozzle because the underlying requirement to create a supersonic, turbulent, and non-uniform flow is common to all satisfactory air-jet texturing nozzles

An analysis of the air-jet yarn texturing process. Part 2, Experimental investigation of the air-flow

An account is given of an experimental investigation of the characteristics of the air-flow in a scaled-up model of a currently used nozzle for the air-jet texturing of yarns. The flow was found to be supersonic, turbulent, and of a non -uniform profile. Flow visualizations of the undisturbed and disturbed flows made by using the actual-size nozzle provided evidence that challenges previously postulated mechanisms of, loop formation based on shock waves

An analysis of the air-jet yarn texturing process. Part 5, The effect of wetting the yarns

It is shown that the quantity of water mixing into the air-flow is an insignificant proportion of the total amount of water used in the air-jet texturing process and that this has a negligible effect on the air-flow in the texturing nozzle. It is suggested that only a fraction of this water is needed to impart the desired effects of wetting. Experimental investigations show that water acts as a lubricant to reduce the filament-filament and filament-solid-surface friction and hence aids the longitudinal displacements of the filaments relative to each other. A realignment of the yarn path minimizes the friction between the filaments and solid surfaces

An analysis of the air-jet yarn texturing process. Part 3, Filament behaviour during texturing

Experiments performed with a current industrial-texturing nozzle on a specially designed singlehead texturing machine are described. These involve the use of high-speed still and cine photography, together with measurements of yam speed on emergence from the nozzle and yarn-tension measurements at various stages of the process. The results of these experiments provide a better understanding of the filament behaviour during the texturing process. They also provide useful information regarding the effects of texturing speed, overfeed ratio, and texturing with and without water on the mechanisms of the process