Response of RC columns with transient creep in a natural fire environment

The aim of this study is to investigate the effect of transient creep on the structural response of RC columns subjected to natural or parametric fires using a finite element model developed by the authors. The model, capable of analysing the response of RC columns from pre-fire stages to collapse in fire environment, is specially developed for the analysis of RC structures under severe thermo-mechanical loads, which accounts for transient creep explicitly as an additional component of the total strain of the concrete or implicitly through the use of the materials’ properties recommended by EC2. Through the obtained results, it is shown that the transient creep phenomenon significantly influences the fire response of RC columns. It was also found that the conventional method based on standard fire exposure may not be conservative if the resulting fire has a decay phase similar to the severe fire scenario used in this work

Radiation effects on electronic circuits in a spatial environment

The failings bound to the deterioration of the components under irradiations are complex and numerous. This paper describes the different kinds of radiations present in the space as well as their interactions with the materials composing the integrated circuits used in the spacecraft. Our survey will be focused on the Single Event Upset phenomenon induced by the passage of only one ionizing particle with applications on the Samsung SDRAM

Declining water resources in response to global warming and changes in atmospheric circulation patterns over southern Mediterranean France

Warming trends are responsible for an observed decrease of water discharge in southern France (northwestern Mediterranean). Ongoing climate change and the likely increase of water demand threaten the availability of water resources over the coming decades. Drought indices like the Reconnaissance Drought Index (RDI) are increasingly used in climate characterization studies, but little is known about the relationships between these indices, water resources, and the overall atmospheric circulation patterns. In this study, we investigate the relationships between the RDI, water discharge, and four atmospheric teleconnection patterns (TPs) for six coastal river basins in southern France, both for the historical period of the last 60 years and for a worst-case climatic scenario (RCP8.5) reaching the year 2100. We combine global and regional climate model (CGM and RCM, respectively) outputs with a set of observed climatic and hydrological data in order to investigate the past relationships between the RDI, water discharge, and TPs and to project their potential evolution in space and time. Results indicate that annual water discharge can be reduced by −49 % to −88 % by the end of the century under the extreme climate scenario conditions. Due to unequal links with TPs, the hydroclimatic evolution is unevenly distributed within the study area. Indeed a clustering analysis performed with the RDI time series detects two major climate clusters, separating the eastern and western part of the study region. The former indicates stronger relationships with the Atlantic TPs (e.g. the North Atlantic Oscillation (NAO) and the Scandinavian Oscillation (Scand) patterns), whereas the latter is more closely related to the Mediterranean TPs (Mediterranean Oscillation (MO) and Western Mediterranean Oscillation (WeMO)). The future climate simulations predict an antagonistic evolution in both clusters which are likely driven by decreasing trends of Scand and WeMO. The former provokes a general tendency of lower P in both clusters during spring, summer, and autumn, whereas the latter might partly compensate for this evolution by enhanced precipitation in the eastern cluster during autumn and winter. However, compared to observations, representation of the Mediterranean TPs WeMO and MO in the considered climate models is less satisfactory compared to the Atlantic TPs NAO and Scand, and further improvement of the model simulations therefore requires better representations of the Mediterranean TPs.</p

EPIdemiology of Surgery-Associated Acute Kidney Injury (EPIS-AKI) : Study protocol for a multicentre, observational trial

More than 300 million surgical procedures are performed each year. Acute kidney injury (AKI) is a common complication after major surgery and is associated with adverse short-term and long-term outcomes. However, there is a large variation in the incidence of reported AKI rates. The establishment of an accurate epidemiology of surgery-associated AKI is important for healthcare policy, quality initiatives, clinical trials, as well as for improving guidelines. The objective of the Epidemiology of Surgery-associated Acute Kidney Injury (EPIS-AKI) trial is to prospectively evaluate the epidemiology of AKI after major surgery using the latest Kidney Disease: Improving Global Outcomes (KDIGO) consensus definition of AKI. EPIS-AKI is an international prospective, observational, multicentre cohort study including 10 000 patients undergoing major surgery who are subsequently admitted to the ICU or a similar high dependency unit. The primary endpoint is the incidence of AKI within 72 hours after surgery according to the KDIGO criteria. Secondary endpoints include use of renal replacement therapy (RRT), mortality during ICU and hospital stay, length of ICU and hospital stay and major adverse kidney events (combined endpoint consisting of persistent renal dysfunction, RRT and mortality) at day 90. Further, we will evaluate preoperative and intraoperative risk factors affecting the incidence of postoperative AKI. In an add-on analysis, we will assess urinary biomarkers for early detection of AKI. EPIS-AKI has been approved by the leading Ethics Committee of the Medical Council North Rhine-Westphalia, of the Westphalian Wilhelms-University Münster and the corresponding Ethics Committee at each participating site. Results will be disseminated widely and published in peer-reviewed journals, presented at conferences and used to design further AKI-related trials. Trial registration number NCT04165369

A novel analytical method for the analysis of a bi-concave cable-truss footbridge

© 2016 Elsevier Ltd.Bi-concave cable truss systems are not only aesthetically appealing but they also offer elegant solutions for spanning large spans required in modern buildings such as convention centres, sport arenas and bridges. These structures, however, are notoriously difficult to model correctly using non-numerical based methods. The existing analytical methods are limited to uniformly distributed loads on half or the entire span, and do not include the stays in the calculations. This paper details a novel analytical method that not only covers wide spectra of loads, including both uniformly distributed and concentrated loads on any part of the span, but also includes the stays in the calculations. The mathematical formulation was based on the fundamental assumption that the hangers form a continuous and inextensible diaphragm. The main two nonlinear equations describing the cable thrusts, unknowns of the problem, were calculated using an orthogonal displacement equation based on the boundary conditions of the cable ends at the anchorages. The predicted results are compared to finite element analysis, and good agreement was found across all the load configurations. The presented method was found to be very efficient and reliable

Response of RC columns with transient creep in a natural fire environment

The aim of this study is to investigate the effect of transient creep on the structural response of RC columns subjected to natural or parametric fires using a finite element model developed by the authors. The model, capable of analysing the response of RC columns from pre-fire stages to collapse in fire environment, is specially developed for the analysis of RC structures under severe thermo-mechanical loads, which accounts for transient creep explicitly as an additional component of the total strain of the concrete or implicitly through the use of the materials’ properties recommended by EC2. Through the obtained results, it is shown that the transient creep phenomenon significantly influences the fire response of RC columns. It was also found that the conventional method based on standard fire exposure may not be conservative if the resulting fire has a decay phase similar to the severe fire scenario used in this work

Structural and electrical properties of as-deposited and annealed DC sputtered ITO thin films

We have studied the effect of annealing on the structural and electrical properties of tin-doped indium oxyde, $\rm In _2O_3{:}Sn$ (ITO), thin films prepared by DC sputtering at different partial pressure of oxygen (ppo). Annealing experiments have been done in vacuum and in Ar atmosphere up to a temperature of 450 °C. A change of texture from $\langle 100\rangle$ to $\langle 111\rangle$ as the ppo was increased was noted in the as-deposited films. Annealing induced cristallinity and improved the texture of these films. The lattice constant decreased after annealing. The (222) grain size increased after vacuum annealing but was unaffected by annealing in Ar atmosphere; while the (400) grain size decreased for samples having the $\langle 100\rangle$ texture. The electrical resistivity decreases sharply after annealing to a minimum value of 87 × 10-4 Ω cm

The Mediterranean Region as a Paradigm of the Global Decoupling of N and P Between Soils and Freshwaters

The global socio-economic and agricultural expansion is accompanied by large inputs of nitrogen (N) and phosphorus (P) on land and by a serious alteration of the water cycle and water quality. The Mediterranean basin represents a paradigmatic region to study the entangled nutrient and water challenges because the region, where many of the world's climatic and socio-economic gradients are present, is predicted to suffer severe water stress in the coming decades yet at the same time agricultural intensification and population are increasing in many rim countries. We here describe the biogeochemical budgets of N and P in 549 river basins for the 2000–2009 period, analyzing how the climatic gradient and water management practices affect the fluxes of N and P and their stoichiometric ratios. Average land inputs are 3,600 kg N km−2 yr−1 and 470 kg P km−2 yr−1, with a significant variation between basins (>100 times) closely related to the stage of agricultural intensification. Moreover, the combination of aridity and water regulation can strongly alter the final balances, not only by changing the export of nutrients by rivers (riverine export is ca. 10% for N and 8% for P in arid basins), but also decoupling the N:P ratios between terrestrial and freshwater compartments

The Mediterranean Region as a Paradigm of the Global Decoupling of N and P Between Soils and Freshwaters

International audienceThe global socio economic and agricultural expansion is accompanied by large inputs of nitrogen (N) and phosphorus (P) on land and by a serious alteration of the water cycle and water quality. The Mediterranean basin represents a paradigmatic region to study the entangled nutrient and water challenges because the region, where many of the world's climatic and socio economic gradients are present, is predicted to suffer severe water stress in the coming decades yet at the same time agricultural intensification and population are increasing in many rim countries. We here describe the biogeochemical budgets of N and P in 549 river basins for the 2000-2009 period, analyzing how the climatic gradient and water management practices affect the fluxes of N and P and their stoichiometric ratios. Average land inputs are 3,600 kg N km−2 yr−1 and 470 kg P km−2 yr−1, with a significant variation between basins (>100 times) closely related to the stage of agricultural intensification. Moreover, the combination of aridity and water regulation can strongly alter the final balances, not only by changing the export of nutrients by rivers (riverine export is ca. 10% for N and 8% for P in arid basins), but also decoupling the N:P ratios between terrestrial and freshwater compartments