Evaluation of interfacial fracture toughness and friction coefficient in the single fiber fragmentation test

Single fiber fragmentation test is extensively employed to characterize the fiber-matrix interface in composites. A novel technique for evaluating fracture toughness and friction coefficient at the fiber-matrix interface in an epoxy sample containing a single glass fiber is proposed. Using experimental measurements of the average fragment and debond lengths, Boundary Element (BE) models of the portion of sample corresponding to the average fiber fragment are created for increasing values of the applied strain. From the solution of the BE models, energy release rate (ERR) during crack propagation is evaluated using a Fracture Mechanics based approach which accounts for fiber-matrix interfacial friction. The calculated evolution of the ERR has a reasonably linear dependency on the applied strain, with a decreasing slope for increasing values of the interfacial friction coefficient. Since debond growth is stable, ERR should equal the interfacial fracture toughness during debond propagation. Consequently, interfacial friction coefficient and fracture toughness can be simultaneously determined by parametrically varying the friction coefficient until a null slope is obtained in the linear fit of the numerical solution of the ERR as a function of the applied strain. The applicability of the proposed technique is demonstrated with experimental results taken from the literature.Junta de Andalucía P08-TEP-0405

Visible light-driven H2 production over highly dispersed Ruthenia on Rutile TiO2 nanorods

The immobilization of miniscule quantities of RuO2 (~0.1%) onto one-dimensional (1D) TiO2 nanorods (NRs) allows H2 evolution from water under visible light irradiation. Rod-like rutile TiO2 structures, exposing preferentially (110) surfaces, are shown to be critical for the deposition of RuO2 to enable photocatalytic activity in the visible region. The superior performance is rationalized on the basis of fundamental experimental studies and theoretical calculations, demonstrating that RuO2(110) grown as 1D nanowires on rutile TiO2(110), which occurs only at extremely low loads of RuO2, leads to the formation of a heterointerface that efficiently adsorbs visible light. The surface defects, band gap narrowing, visible photoresponse, and favorable upward band bending at the heterointerface drastically facilitate the transfer and separation of photogenerated charge carriers.Peer ReviewedPostprint (published version

The Front End Electronics of the Scintillator Pad Detector of LHCb Calorimeter

In this paper the Front End electronics of the Scintillator Pad Detector (SPD) is outlined. The SPD is a sub-system of the Calorimeter of the LHCb experiment designed to discriminate between charged and neutral particles for the first level trigger. The system design is presented, describing its different functionalities implemented through three different cards and several ASICs. These functionalities are signal processing and digitization, data transmission, interface with control and timing systems of the experiment, low voltage power supply distribution and monitoring. Special emphasis is placed on installation and commissioning subjects such as cabling, grounding, shielding and power distribution

Trends in hypertension control among the older population of Spain from 2000 to 2001 to 2008 to 2010: Role of frequency and intensity of drug treatment

This is the prepint version of the following article: Circulation: Cardiovascular Quality and Outcomes 8.1 (2015) , which has been published in final form at http://dx.doi.org/10.1161/CIRCOUTCOMES.114.001191Background—The use of antihypertensive medication and hypertension control has significantly increased during recent decades in some developed countries, but the impact of improved drug treatment on blood pressure (BP) control in the population is unknown. Methods and Results—Data were taken from 2 surveys representative of the population aged ≥60 years in Spain conducted with the same methodology in 2000 to 2001 and in 2008 to 2010. BP was measured 6×. The first BP reading was discarded, and the average of the remaining 3 to 5 BP readings was taken for analysis. Hypertension prevalence was 68.7% in 2000 to 2001 and 66.0% in 2008 to 2010. Between both time periods there was an improvement in hypertension awareness (63.6%–67.7%), drug treatment among those aware (84.5%–87.5%), and BP control among treated hypertensives (30.3%–42.9%). Overall, BP control among all hypertensives increased from 16.3% to 25.4%. After adjustment for age, sex, education, hypertension duration, smoking, alcohol consumption, body mass index, sedentary behavior, diabetes mellitus, cardiovascular disease, and visits to the physician through logistic regression, ≈7% of the improvement in BP control among all hypertensives was explained by higher hypertension awareness, and 36.2% was explained by a higher treatment rate. Among the treated hypertensives, 22.6% of the progress in BP control was because of the increase in the number of BP medications used in each patient. Conclusions—BP control among the older hypertensive population in Spain has improved from 2000 to 2001 to 2008 to 2010 because of a higher treatment rate and more intense antihypertensive drug treatmentThis work has been supported by Fondo de Investigación Sanitaria (FIS) grant PI13/02321 (Instituto de Salud Carlos III, Spain) and “Cátedra Universidad Autónoma de Madrid (UAM) de Epidemiología y Control del Riesgo Cardiovascular”, Madrid, Spain

Stability and Electronic Properties of TiO2 Nanostructures With and Without B and N Doping

We address one of the main challenges to TiO2-photocatalysis, namely band gap narrowing, by combining nanostructural changes with doping. With this aim we compare TiO2's electronic properties for small 0D clusters, 1D nanorods and nanotubes, 2D layers, and 3D surface and bulk phases using different approximations within density functional theory and GW calculations. In particular, we propose very small (R < 0.5 nm) but surprisingly stable nanotubes with promising properties. The nanotubes are initially formed from TiO2 layers with the PtO2 structure, with the smallest (2,2) nanotube relaxing to a rutile nanorod structure. We find that quantum confinement effects - as expected - generally lead to a widening of the energy gap. However, substitutional doping with boron or nitrogen is found to give rise to (meta-)stable structures and the introduction of dopant and mid-gap states which effectively reduce the band gap. Boron is seen to always give rise to n-type doping while depending on the local bonding geometry, nitrogen may give rise to n-type or p-type doping. For under coordinated TiO2 surface structures found in clusters, nanorods, nanotubes, layers and surfaces nitrogen gives rise to acceptor states while for larger clusters and bulk structures donor states are introduced

Low pressure CO2 hydrogenation to methanol over gold nanoparticles activated on a CeOx/TiO2 Interface

Capture and recycling of CO2 into valuable chemicals such as alcohols could help mitigate its emissions into the atmosphere. Due to its inert nature, the activation of CO2 is a critical step in improving the overall reaction kinetics during its chemical conversion. Although pure gold is an inert noble metal and cannot catalyze hydrogenation reactions, it can be activated when deposited as nanoparticles on the appropriate oxide support. In this combined experimental and theoretical study, it is shown that an electronic polarization at the metal-oxide interface of Au nanoparticles anchored and stabilized on a CeOx/TiO2 substrate generates active centers for CO2 adsorption and its low pressure hydrogenation, leading to a higher selectivity toward methanol. This study illustrates the importance of localized electronic properties and structure in catalysis for achieving higher alcohol selectivity from CO2 hydrogenation.U.S. Department of Energy DE-AC02- 98CH10886, DE-AC02-05CH11231Brookhaven National Laboratory DE-SC001270

Impact of ambulatory blood pressure monitoring on reclassification of hypertension prevalence and control in older people in Spain

This is the submitted version of the following article: Impact of ambulatory blood pressure monitoring on reclassification of hypertension prevalence and control in older people in Spain, Journal of Clinical Hypertension 17.6:453-61 which has been published in final form at http://dx.doi.org/10.1111/jch.12525. This article may be used for non-commercial purposes in accordance with the Wiley Self-Archiving Policy wiley.com/WileyCDA/Section/id- 820227.htmlAmbulatory blood pressure monitoring (ABPM) accurately classifies blood pressure (BP) status but its impact on the prevalence and control of hypertension is little known. The authors conducted a cross-sectional study in 2012 among 1047 individuals 60 years and older from the follow-up of a population cohort in Spain. Three casual BP measurements and 24-hour ABPM were performed under standardized conditions. Approximately 68.8% patients were hypertensive based on casual BP (≥140/90 mm Hg or current BP medication use) and 62.1% based on 24-hour ABPM (≥130/80 mm Hg or current BP medication use) (P=.009). The proportion of patients with treatment-eligible hypertension who met BP goals increased from 37.4% based on the casual BP target to 54.1% based on the 24-hour BP target (absolute difference, 16.7%; P<.01). These results were consistent across alternative BP thresholds. Therefore, compared with casual BP, 24-hour ABPM led to a reduction in the proportion of older patients recommended for hypertension treatment and a substantial increase in the proportion of those with hypertension controlData collection was funded by Fondo de Investigación Sanitaria (FIS) grants 09/1626 and 12/1166 (Ministry of Health of Spain) and by the ‘Cátedra UAM de Epidemiología y Control del Riesgo Cardiovascular’. Specific funding for this analysis was obtained from FIS grant PI13/02321