1,576 research outputs found
NMR Characterizations of Candidate Battery Electrolytes
Enormous strides have been made in next-generation power sources to build a more sustainable society. Energy storage has become a limiting factor in our progress, and there are huge environmental and financial incentives to find the next step forward in battery technology. This work discusses NMR methods for characterizing materials for use in battery application, with a special focus on relaxometry and diffusometry. Examples are provided of various recent investigations involving novel candidate electrolyte materials with different collaborators. Works discussed in this thesis include: the characterization of a new disruptive solid polymer electrolyte technology, investigations of the dynamics of super concentrated aqueous electrolytes, and studies of glyme-based electrolytes. Experimental results are interpreted and the impact on the continued development of the materials is analyzed
Modelling thermal fluxes at the soil surface
This paper investigates the impact that various representations of thermal fluxes at the soil surface have on the estimation of seasonal variations of temperature and stored thermal energy in the soil close to the surface. Three theoretical formulations representing; turbulent, nonturbulent and vegetation-covered soil surface conditions are considered. The influence of shading from nearby objects (e.g. vegetation) has also been investigated. Numerical predictions of soil temperature and stored thermal energy are compared with experimental results from a large scale field test (performed by others). The results of both 1D and 2D simulations are shown capable of representing specific aspects of field behaviour. Various sources of meteorological data have been used to define surface boundary conditions. In particular, simulations were performed using; i) data measured in-situ, ii) data obtained from The British Atmospheric Data Centre, and iii) data generated using analytical expressions found in the literature. It is found that the correct representation of the heat transfer processes occurring at the soil surface is of critical importance. In particular, it is shown that the use of publicly available sources of data, or mathematical/analytical expressions for meteorological data, may be adequate when in-situ measurements are not available
Review of Recent Nuclear Magnetic Resonance Studies of Ion Transport in Polymer Electrolytes
Current and future demands for increasing the energy density of batteries without sacriïŹcing safety has led to intensive worldwide research on all solid state Li-based batteries. Given the physical limitations on inorganic ceramic or glassy solid electrolytes, development of polymer electrolytes continues to be a high priority. This brief review covers several recent alternative approaches to polymer electrolytes based solely on poly(ethyleneoxide) (PEO) and the use of nuclear magnetic resonance (NMR) to elucidate structure and ion transport properties in these materials
Community structures, interactions and dynamics in Londonâs bicycle sharing network
Bikesharing schemes are transportation systems that not only provide an efficient mode of transportation in congested urban areas, but also improve last-mile connectivity with public transportation and local accessibility. Bikesharing schemes around the globe generate detailed trip data sets with spatial and temporal dimensions, which, with proper mining and analysis, reveal valuable information on urban mobility patterns. In this paper, we study the London bicycle sharing dataset to explore community structures. Using a novel clustering technique, we derive distinctive behavioural patterns and assess community interactions and spatio-temporal dynamics. The analyses reveal self-contained, interconnected and hybrid clusters that mimic Londonâs physical structure. Exploring changes over time, we find geographically isolated and specialized communities to be relatively consistent, while the remaining system exhibits volatility, especially during and around peak commuting times. By increasing our understanding of the collective behaviour of the bikesharing users, this analysis supports policy appraisal, operational decision-making and motivates improvements in infrastructure design and management
Barriers and facilitators to participating in cardiac rehabilitation and physical activity in a remote and rural population: A cross-sectional survey
Background: Cardiac disease requires ongoing active management which may include attendance at formal cardiac rehabilitation (CR) and increased physical activity (PA). However, uptake rates are sub-optimal. This study aimed to identify factors associated with attendance at CR and PA in a rural Scottish population.Methods: A cross-sectional postal survey assessing factors potentially associated with attending CR and participating in PA. Data were also collected from hospital electronic medical records. Binary logistic and ordinal regressions were used to identify barriers and facilitators to participation.Results: The cohort consisted of 840 participants referred to the CR department of a regional Scottish hospital. After applying the inclusion/exclusion criteria, 567 patients were sent a questionnaire. The number of returned questionnaires was 295 (52.0%). Responders were predominantly male (75.9%), with a mean age of 68.7 years. At the multivariate level, the only factor associated with CR attendance was a lack of perceived need (odds ratio [OR] 0.02, 95% confidence interval [CI] 0.01â0.06). Analyses of PA associations identified self-efficacy as the only significant facilitator (OR 1.29, 95% CI 1.05â1.59), and a lack of willpower as the only barrier (OR 0.42, 95% CI 0.18â0.97). Other factors were linked to CR attendance and PA at a univariate level only.Conclusions: This study characterised CR and PA participation, and explored demographic, medical, and psychological factors associated with both activities â with the most important being perceived need, self-efficacy and willpower. These findings may be beneficial in clinical practice by targeting these factors to increase CR attendance and PA levels
Barriers and facilitators to participating in cardiac rehabilitation and physical activity in a remote and rural population : A cross-sectional survey
The authors are grateful to the staff of the Research, Development and Innovation offices, who assisted in the distribution and collection of questionnaires, and the Cardiac Rehabilitation staff. The authors would like to thank all patients involved in this study. Funding: DC was funded by Highlands and Islands Enterprise (project number HMS 9353763)Peer reviewedPublisher PD
The Influence of Bio-syngas Composition on the Derating of Solid Oxide Fuel Cellsâ
Abstract In this work, the performance of solid oxide fuel cells (SOFCs) fed with a syngas obtained from a steam-enriched air gasification of biomass has been investigated, varying the composition of the feeding gas (H2, CO, CO2, CH4, H2O, and N2). The composition has been obtained from experimental/numerical tests in a fluidized bed bench scale gasifier after catalytic steam reforming of the syngas carried out to remove tar. During the gasification tests, the oxygen purity in the enriched air (in the range of 0.2 and 0.9), the gasification process temperature (in the range of 750 and 850 °C), the steam to biomass (in the range of 0.5 and 1) and the equivalence ratio (in the range between 0.0 and 0.4) were varied to simulate the different operating conditions. Commercial SOFC cells have been employed in the experimental campaign, fed with the most representative fuel compositions mentioned above. Polarization curves have been carried out to determine the electrical performance of the cells, comparing the results with cells fed with hydrogen only. In the final paper, the electrochemical impedance spectroscopy (EIS) will be reported for in-depth analysis of the performance parameters and to evaluate the long term degradation rate of the cell
Bronchial Thermoplasty Global Registry (BTGR): 2-year results
Asma; BroncoscĂČpia; TermoplĂ stia bronquialAsma; Broncoscopia; Termoplastia bronquialAsthma; Bronchoscopy; Bronchial ThermoplastyObjectives: Bronchial thermoplasty (BT) is a device-based treatment for subjects â„18 years with severe asthma not well controlled with inhaled corticosteroids and long-acting beta-agonists. The Bronchial Thermoplasty Global Registry (BTGR) collected real-world data on subjects undergoing this procedure.
Design: The BTGR is an all-comer, prospective, open-label, multicentre study enrolling adult subjects indicated for and treated with BT.
Setting: Eighteen centres in Spain, Italy, Germany, the UK, the Netherlands, the Czech Republic, South Africa and Australia PARTICIPANTS: One hundred fifty-seven subjects aged 18 years and older who were scheduled to undergo BT treatment for asthma. Subjects diagnosed with other medical conditions which, in the investigator's opinion, made them inappropriate for BT treatment were excluded.
Primary and secondary outcome measures: Baseline characteristics collected included demographics, Asthma Quality of Life Questionnaire (AQLQ), Asthma Control Test (ACT), medication usage, forced expiratory volume in one second and forced vital capacity, medical history, comorbidities and 12-month baseline recall data (severe exacerbations (SE) and healthcare utilisation). SE incidence and healthcare utilisation were summarised at 1 and 2 years post-BT.
Results: Subjects' baseline characteristics were representative of persons with severe asthma. A comparison of the proportion of subjects experiencing events during the 12 months prior to BT to the 2-year follow-up showed a reduction in SE (90.3% vs 56.1%, p<0.0001), emergency room visits (53.8% vs 25.5%, p<0.0001) and hospitalisations (42.9% vs 23.5 %, p=0.0019). Reductions in asthma maintenance medication dosage were also observed. AQLQ and ACT scores improved from 3.26 and 11.18 at baseline to 4.39 and 15.54 at 2 years, respectively (p<0.0001 for both AQLQ and ACT).
Conclusions: The BTGR demonstrates sustained improvement in clinical outcomes and reduction in asthma medication usage 2 years after BT in a real-world population. This is consistent with results from other BT randomised controlled trials and registries and further supports improvement in asthma control after BT.This study was sponsored by Boston Scientific Corporation, Marlborough, MA, USA
- âŠ