Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

A coinductive treatment of infinitary term rewriting and equational reasoning

Engineering, Systems and ServicesTechnology, Policy and Managemen

Effect of nanostructured lime-based and silica-based products on the consolidation of historical renders

An important operation for the conservation of historical renders is the cohesion restitution of the binderaggregate system, based on the use of materials with consolidating properties. Inorganic consolidants are usually preferred to organic ones due to better compatibility and durability. The aim of this work is the experimental characterization of two nanostructured consolidant products; a commercial nanolime, optimized with the addition of a reduced concentration of ethyl silicate, and a commercial nanosilica product underwent experiments to verify their consolidation efficiency. Nanostructured lime-based and silica-based products present interesting properties such as homogeneous distribution and high stability. Nanolimes were applied in combined applications with ethyl silicate, a well-known compatible product for consolidation intervention. The combined application guarantees some benefits and improves the mechanical and microstructural performance of these products. A nanosilica product was tested to better understand some known disadvantages (e.g. reduced penetration depth) and so its performances. Consolidant products were applied on weak lime mortar samples (prismatic samples and single mortar layer applied on bricks); these mortars were optimized by studying different binder-aggregate ratios, to simulate old lime mortar with cohesion loss. Consolidation effects were periodically evaluated to understand the treatments efficacy. Physicalmechanical characterization was performed on treated mortar samples, analysing superficial hardness and compressive and flexural strength. Microstructural observations and X-ray microanalyses of the consolidation products and of the consolidated mortar samples are also reported.Architectural Engineering +TechnologyArchitecture and The Built Environmen

Characteristics of the intense vorticity structures in isotropic turbulence at high Reynolds numbers

Direct numerical simulations (DNS) of forced (statistically stationary) isotropic turbulence are used to assess the characteristics of the intense vorticity structures (IVS) or "worms"at higher Reynolds numbers than previously available. The simulations cover a range of Taylor-based Reynolds numbers in the range 90≤Reλ≤399, for a resolution of kmaxη≈2.0, where kmax is the maximum resolved wave number and η is the Kolmogorov microscale. Most of the IVS characteristics are confirmed at the higher Reynolds numbers analyzed in this work; e.g., the results confirm that the mean radius of the IVS (Rivs) is approximately equal to (Rivs)/η≈4-5 and that the mean radius is equal to the radius of the stationary Burgers vortex (Rivs/RB)≈1.0, with RB=2(ν/α)1/2, where ν is the kinematic viscosity and α is the (locally) imposed rate of strain. Moreover, the tangential velocity of the IVS scales with the root-mean-square velocity of the flow Uivs∼u′. These IVS characteristics seem to be robust and relatively independent of the Reynolds number; however, there are other quantities for which the classical results do not hold. A notable example is the mean length of the IVS (Livs), which previous works, carried out at smaller Reynolds numbers, claimed to scale with either the Taylor microscale λ or the integral scale of turbulence L. It turns out that the correct scaling for this quantity can be observed only at Reλ200, and the results consistently show that Livs scales with the Kolmogorov microscale Livs∼η, with a mean value equal to (Livs)≈60η. The present findings provide further evidence that Reλ200 is required for the small scales to be fully developed.Fluid Mechanic

Enhanced Fatigue Life of Old Metallic Bridges - Application of Preloaded Injection Bolts

There is a significant number of old metallic bridges with high levels of structural degradation due to their long service period. Fatigue problems are especially important in these structures since the majority of them were not designed taking into account this phenomenon. Several investigations showed that riveted joints are critical details since several fatigue cracks were found in these joints. In this sense, strengthening methodologies need to be studied. The strategy that has been considered a good solution is the implementation of injection bolts to replace faulty rivets. The structural performance of injection bolts has been demonstrated essentially under quasi-static conditions presenting good results. This paper intends to contribute to the scientific knowledge regarding the fatigue behavior of connections with preloaded injection bolts in the context of a bridge strengthening scenario. An experimental investigation was conducted to compare the fatigue performance of connections with preloaded injection bolts and preloaded standard bolts. Single and double shear connections were tested. New S–N design curves were proposed based on a statistical analysis of the results and compared with the S–N curves proposed in EC3-1–9. The obtained results showed that the use of injection bolts lead to lower scatter and improvement of fatigue life. It was verified that the Eurocode 3 is not able to represent the fatigue strength of connections whose performance is influenced by old metallic materials. Additionally, the fatigue behavior of these connections was assessed by numerical analysis. The relevance of the fatigue crack initiation was evident.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Steel & Composite Structure

A posteriori uncertainty quantification of PIV-derived pressure fields

The present work proposes a methodology for the a posteriori quantification of the uncertainty of pressure data retrieved from PIV measurements. It relies upon the Bayesian framework, where the posterior distribution (probability distribution of the true velocity, given the PIV measurements) is obtained from the prior distribution (prior knowledge of the velocity, e.g., within a certain bound or divergence-free) and the distribution representing the PIV measurement uncertainty. Once the posterior covariance matrix of the velocity is known, it is propagated through the discretized Poisson equation for pressure. Numerical assessment of the proposed method on a steady Lamb Oseen vortex shows excellent agreement with Monte Carlo simulations, while linear uncertainty propagation underestimates the uncertainty of the pressure by up to 30%. The method is finally applied to an experimental test case of a turbulent boundary layer in air, obtained using time-resolved tomographic PIV. The pressure reconstructed from tomographic PIV data is compared to a microphone measurement conducted simultaneously at the wall to determine the actual error of the former. The comparison between actual error and estimated uncertainty shows the accuracy of the proposed method for uncertainty quantification of pressure data from tomographic PIV experiments: for a 95% confidence level, 93% of the data points fall within the estimated uncertainty bound with the Eulerian approach, and 90% with the Lagrangian approach. When using the prior knowledge that the velocity field should be divergence-free, these values are 98% with the Eulerian approach and 94% with the Lagrangian approach. The Lagrangian approach results in more accurate reconstructed pressure fields than the Eulerian approach. Also, enforcing the divergence-free constraint is found to result in a more accurate reconstructed pressure field. Both observations also follow from the uncertainty quantification, through a decrease in the estimated uncertainty.Aerodynamics, Wind Energy & PropulsionAerospace Engineerin

Use of algebraic dual spaces in domain decomposition methods for Darcy flow in 3D domains

In this work we use algebraic dual spaces with a domain decomposition method to solve the Darcy equations. We define the broken Sobolev spaces and their finite dimensional counterparts. A global trace space is defined that connects the solution between the broken spaces. Use of algebraic dual spaces results in a sparse, metric-free representation of the incompressibility constraint, the pressure gradient term, and on the continuity constraint between the sub domains. To demonstrate this, we solve two test cases: (i) a manufactured solution case, and (ii) an industrial benchmark reservoir modelling problem SPE10. The results demonstrate that the dual spaces can be used for domain decomposition formulation, and despite having more unknowns, requires less simulation time compared to the continuous Galerkin formulation, without compromising on the accuracy of the solution.Aerodynamic

Causal Effects between Criteria That Establish the End of Service Life of Buildings and Components

In the last decades, considerable work has been done regarding service life prediction of buildings and building components. Academics and members of the CIB W080 commission, as well as of ISO TC 59/SC14, have made several efforts in this area and created a general terminology for the concept of service life, which is extremely relevant for property management, life cycle assessment (LCA) and life cycle costs (LCC) analyses. Various definitions can be found in the literature that share common ideas. In fact, there are different criteria that trigger the end of a building’s service life, but the trap that building practitioners too often fall into and that should be avoided is dividing a problem into separate boxes, labels, and specializations without the mutual cohesion and interaction, and ignoring human behavior. Some definitions of service life are discussed in this review paper, in which the cause-effect processes underlying aging and decay are described. These descriptions highlight the continuous interrelation between different criteria for the end of a building’s service life, considering too often neglected and misunderstood causes of the end of life.Housing Quality and Process InnovationDesign & Construction Managemen

A posteriori uncertainty quantification of PIV-based pressure data

A methodology for a posteriori uncertainty quantification of pressure data retrieved from particle image velocimetry (PIV) is proposed. It relies upon the Bayesian framework, where the posterior distribution (probability distribution of the true velocity, given the PIV measurements) is obtained from the prior distribution (prior knowledge of properties of the velocity field, e.g., divergence-free) and the statistical model of PIV measurement uncertainty. Once the posterior covariance matrix of the velocity is known, it is propagated through the discretized Poisson equation for pressure. Numerical assessment of the proposed method on a steady Lamb–Oseen vortex shows excellent agreement with Monte Carlo simulations, while linear uncertainty propagation underestimates the uncertainty in the pressure by up to 30 %. The method is finally applied to an experimental test case of a turbulent boundary layer in air, obtained using time-resolved tomographic PIV. Simultaneously with the PIV measurements, microphone measurements were carried out at the wall. The pressure reconstructed from the tomographic PIV data is compared to the microphone measurements. Realizing that the uncertainty of the latter is significantly smaller than the PIV-based pressure, this allows us to obtain an estimate for the true error of the former. The comparison between true error and estimated uncertainty demonstrates the accuracy of the uncertainty estimates on the pressure. In addition, enforcing the divergence-free constraint is found to result in a significantly more accurate reconstructed pressure field. The estimated uncertainty confirms this result.AerodynamicsWind Energ

Deposition of modified nanolimes within calcareous substrates

Architectural Engineering +TechnologyArchitecture and The Built Environmen