CFD analysis of devices i oscillating water column - OWC

The paper is about the development of a fluid-dynamic model for simulating the behaviour of a device for the production of electric energy based on an oscillating water column (OWC). First of all it has been developed a 3-D model of the device using a tool in order to create the grid used for the simulation. The code used for the fluid dynamic simulation is OpenFoam, in particular the solver InterFoam suitable for two-phase isothermal flow characterized by immiscible and incompressible fluids, it uses the VOF (Volume of Fluids) model. The aim of this work is the optimization of the model from the computational point of view, in particular it has been conducted a sensitivity analysis on the processor’s number and on the time step of calculation. In the first phase of the work were taken into account two forcing, approximated with a sinusoidal profile, corresponding to two types of waves more realistic for the site in which it was made the experimental apparatus. Subsequently it has been developed an analysis of the boundary condition in order to simulate in the best way the incident wave. Obviously it is possible to investigate more in detail the model realized in order to optimize the simulation and validate the model with more experimental data

From Non-Disjoint Combination to Satisfiability and Model-Checking of Infinite State Systems

In the first part of our contribution, we review recent results on combined constraint satisfiability for first order theories in the non-disjoint signatures case: this is done mainly in view of the applications to temporal satisfiability and model-checking covered by the second part of our talk, but we also illustrate in more detail some case-study where non-disjoint combination arises. The first case deals with extensions of the theory of arrays where indexes are endowed with a Presburger arithmetic structure and a length expressing `dimension\u27 is added; the second case deals with the algebraic counterparts of fusion in modal logics. We then recall the basic features of the Nelson-Oppen method and investigate sufficient conditions for it to be complete and terminating in the non-disjoint signatures case: for completeness we rely on a model-theoretic $T_0$-compatibility condition (generalizing stable infiniteness) and for termination we impose a noetherianity requirement on positive constraints chains. We finally supply examples of theories matching these combinability hypotheses. In the second part of our contribution, we develop a framework for integrating first-order logic (FOL) and discrete Linear time Temporal Logic (LTL). Manna and Pnueli have extensively shown how a mixture of FOL and LTL is sufficient to precisely state verification problems for the class of reactive systems: theories in FOL model the (possibly infinite) data structures used by a reactive system while LTL specifies its (dynamic) behavior. Our framework for the integration is the following: we fix a theory $T$ in a first-order signature $Sigma$ and consider as a temporal model a sequence $cM_1, cM_2, dots$ of standard (first-order) models of $T$ and assume such models to share the same carrier (or, equivalently, the domain of the temporal model to be `constant\u27). Following Plaisted, we consider symbols from a subsignature $Sigma_r$ of $Sigma$ to be emph{rigid}, i.e. in a temporal model $cM_1, cM_2, dots$, the $Sigma_r$-restrictions of the $cM_i$\u27s must coincide. The symbols in $Sigmasetminus Sigma_r$ are called `flexible\u27 and their interpretation is allowed to change over time (free variables are similarly divided into `rigid\u27 and `flexible\u27). For model-checking, the emph{initial states} and the emph{transition relation} are represented by first-order formulae, whose role is that of (non-deterministically) restricting the temporal evolution of the model. In the quantifier-free case, we obtain sufficient conditions for %undecidability and decidability for both satisfiability and model-checking of safety properties emph{by lifting combination methods} for emph{non-disjoint} theories in FOL: noetherianity and $T_0$-compatibility (where $T_0$ is the theory axiomatizing the rigid subtheory) gives decidability of satisfiability, whereas $T_0$-compatibility and local finiteness give safety model-checking decidability. The proofs of these decidability results suggest how decision procedures for the constraint satisfiability problem of theories in FOL and algorithms for checking the satisfiability of propositional LTL formulae can be integrated. This paves the way to employ efficient Satisfiability Modulo Theories solvers in the model-checking of infinite state systems. We illustrate our techniques on some examples and discuss further work in the area

BDP/formoterol MART asthma exacerbation benefit increases with blood eosinophil level

A number of studies have evaluated the effectiveness of a “Maintenance And Reliever Therapy” (MART) regimen combining in a single inhaler the rapid-acting, long-acting β2-agonist (LABA) formoterol fumarate (FF) with an inhaled corticosteroid (ICS) in asthma. Such a regimen is now established for the treatment of moderate-to-severe asthma in adolescents and adults in many guidelines. Furthermore, rescue short-acting β2-agonists (SABAs) are no longer recommended as sole therapy even for patients with mild asthma, and an ICS/FF combination used as needed is the preferred reliever therapy

Determinants and impact of suboptimal asthma control in Europe : The INTERNATIONAL CROSS-SECTIONAL AND LONGITUDINAL ASSESSMENT ON ASTHMA CONTROL (LIAISON) study

Acknowledgements We are grateful to THERAmetrics for the study management, data collection and analysis. The authors would like to thank the following investigators for their contribution (>30 patients enrolled): F. Fohler, A.G. Haider, J. Hesse-Tonsa, J. Messner, W. Pohl (Austria); G. Joos, J.L. Halloy, R. Peche, H. Simonis, P. Van den Brande (Belgium); B. Bugnas, J.M. Chavaillon, P. Debove, S. Dury, L. Mathieu, O. Lagrange, A. Prudhomme, S. Verdier (France); A. Benedix, O. Kestermann, A. Deimling, G. Eckhardt, M. Gernhold, V. Grimm-Sachs, M. Hoefer, G. Hoheisel, C. Stolpe, C. Schilder, M. John, J. Uerscheln, K.H. Zeisler (Germany); A. Chaniotou, P. Demertzis, V. Filaditaki-Loverdou, A. Gaga, E. Georgatou-Papageorgiou, S. Michailidis, G. Pavkalou, M. Toumpis (Greece); K. Csicsari, K. Hajdu, M. Póczi, M. Kukuly, T. Kecskes, C. Hangonyi, J. Schlezak, E. Takács, M. Szabo,G. Szabó, C. Szabo (Hungary); G.W. Canonica, W. Castellani, A. Cirillo, M.P. Foschino Barbaro, M. Gjomarkaj, G. Guerra, G. Idotta, D. Legnani, M. Lo Schiavo, R. Maselli, F. Mazza, S. Nutini, P. Paggiaro, A. Pietra, O. Resta, S. Salis, N.A. Scichilone, M.C. Zappa, A. Zedda (Italy); M. Goosens, R. Heller, K. Mansour, C. Meek, J. van den Berg (The Netherlands); A. Antczak, M. Faber, D. Madra-Rogacka, G. Mincewicz, M. Michnar, D. Olejniczak, G. Pulka, Z. Sankowski, K. Kowal, I. Krupa-Borek, B. Kubicka Kozik, K. Kuczynska, P. Kuna, A. Kwasniewski, M. Wozniak (Poland); F. Casas Maldonado, C. Cisneros, J. de Miguel Díez, L.M. Entrenas Costa, B. Garcìa-Cosio, M.V. Gonzales, L. Lores, M. Luengo, C. Martinez, C. Melero, I. Mir, X. Munoz, A. Pacheco, V. Plaza, J. Serra, J. Serrano, J.G. Soto Campos (Spain); T. Bekci, R. Demir, N. Dursunoglu, D. Ediger, A. Ekici, O. Goksel, H. Gunen, I.K. Oguzulgen, Z.F. Ozseker, (Turkey); L. Barnes, T. Hall, S. Montgomerie, J. Purohit, J. Ryan (United Kingdom). The authors would also like to thank P. Galletti (THERAMetrics S.p.A., Sesto San Giovanni, Italy) and K. Stockmeyer (THERAMetrics GmbH, Essen, Germany) for providing editorial assistance in the preparation of this manuscript.Peer reviewedPublisher PD

La radiologia interventistica nel trattamento delle stenosi venose centrali nei pazienti con FAV dialitiche

Abstract non disponibil

New Trends in Designing Parabolic trough Solar Concentrators and Heat Storage Concrete Systems in Solar Power Plants

Energy availability has always been an essential component of human civilization and the energetic consumption is directly linked to the produced wealth. In many depressed countries the level of solar radiation is considerably high and it could be the primary energy source under conditions that low cost, simple-to-be-used technologies are employed. Then, it is responsibility of the most advanced countries to develop new equipments to allow this progress for taking place. A large part of the energetic forecast, based on economic projection for the next decades, ensure us that fossil fuel supplies will be largely enough to cover the demand. The predicted and consistent increase in the energetic demand will be more and more covered by a larger use of fossil fuels, without great technology innovations. A series of worrying consequences are involved in the above scenario: important climatic changes are linked to strong CO2 emissions; sustainable development is hindered by some problems linked to certainty of oil and natural gas supply; problems of global poverty are not solved but amplified by the unavoidable increase in fossil fuel prices caused by an increase in demand. These negative aspects can be avoided only if a really innovative and more acceptable technology will be available in the next decades at a suitable level to impress a substantial effect on the society. Solar energy is the ideal candidate to break this vicious circle between economic progress and consequent greenhouse effect. The low penetration on the market shown today by the existent renewable technologies, solar energy included, is explained by well-known reasons: the still high costs of the produced energy and the \u201cdiscontinuity\u201d of both solar and wind energies. These limitations must be removed in reasonable short times, with the support of innovative technologies, in view of such an urgent scenario. On this purpose ENEA, on the basis of the Italian law n. 388/2000, has started an R&D program addressed to the development of CSP (Concentrated Solar Power) systems able to take advantage of solar energy as heat source at high temperature. One of the most relevant objectives of this research program (Rubbia, 2001) is the study of CSP systems operating in the field of medium temperatures (about 550\ub0C), directed towards the development of a new and low-cost technology to concentrate the direct radiation and efficiently convert solar energy into high temperature heat; another aspect is focused on the production of hydrogen by means of thermo-chemical processes at temperatures above 800\ub0C. As well as cost reductions, the current innovative ENEA conception aims to introduce a set of innovations, concerning: i) The parabolic-trough solar collector: an innovative design to reduce production costs, installation and maintenance and to improve thermal efficiency is defined in collaboration with some Italian industries; ii) The heat transfer fluid: the synthetic hydrocarbon oil, which is flammable, expensive and unusable beyond 400\ub0C, is substituted by a mixture of molten salts (sodium and potassium nitrate), widely used in the industrial field and chemically stable up to 600\ub0C; iii) The thermal storage (TES): it allows for the storage of solar energy, which is then used when energy is not directly available from the sun (night and covered sky) (Pilkington, 2000). After some years of R&D activities, ENEA has built an experimental facility (defined within the Italian context as PCS, \u201cProva Collettori Solari\u201d) at the Research Centre of Casaccia in Rome (ENEA, 2003), which incorporates the main proposed innovative elements. The next step is to test these innovations at full scale by means of a demonstration plant, as envisioned by the \u201cArchimede\u201d ENEA/ENEL Project in Sicily. Such a project is designed to upgrade the ENEL thermo-electrical combined-cycle power plant by about 5 MW, using solar thermal energy from concentrating parabolic-trough collectors. Particularly, the Chapter will focus on points i) and iii) above: - loads, actions, and more generally, the whole design procedure for steel components of parabolic-trough solar concentrators will be considered in agreement with the Limit State method, as well as a new approach will be critically and carefully proposed to use this method in designing and testing \u201cspecial structures\u201d such as the one considered here; - concrete tanks durability under prolonged thermal loads and temperature variations will be estimated by means of an upgraded F.E. coupled model for heat and mass transport (plus mechanical balance). The presence of a surrounding soil volume will be additionally accounted for to evaluate environmental risk scenarios. Specific technological innovations will be considered, such as: -higher structural safety related to the reduced settlements coming from the chosen shape of the tank (a below-grade cone shape storage); - employment of HPC containment structures and foundations characterized by lower costs with respect to stainless steel structures; - substitution of highly expensive corrugated steel liners with plane liners taking advantage of the geometric compensation of thermal dilations due to the conical shape of the tank; - possibility of employing freezing passive systems for the concrete basement made of HPC, able to sustain temperature levels higher than those for OPC; - fewer problems when the tank is located on low-strength soils

Heat Exchange Analysis on Latent Heat Thermal Energy Storage Systems Using Molten Salts and Nanoparticles as Phase Change Materials

The increase of carbon dioxide emissions is the most important contributor to climate change. A better use of produced energy, increasing systems efficiency and using renewable sources, can limit them. A key technological issue is to integrate a thermal energy storage (TES). It consists in stocking thermal energy through the heating/cooling of a storage material for future needs. Among various technologies, latent heat TES (LHTES) provides high energy storage density at constant temperature during melting/solidification of storage media. The bottleneck in the use of typical PCMs is their low thermal conductivity. To improve the heat exchange between heat transfer fluid and PCM, three methods are possible and here experimentally analyzed: conductivity systems enhancements; convective flows promotion in liquid phase; and improvement of PCM thermal properties including small amounts of nanoparticles. CFD models were used to evaluate physical phenomena that are crucial for optimized LHTES systems design. The study of the heat exchange mode allowed some useful indications to achieve an optimized LHTES, taking advantage by convective flows and conductivity promotion systems. The use of NEPCM, to maximize the stored energy density and realize compact systems, makes necessary the improvement of its thermal diffusivity. These will be the future research topics

driftwood biomass in italy estimation and characterization

In Italy, the accumulation of driftwood along the shore is a significant issue, especially for the coastal municipalities of the Central and Northern regions. The purpose of this study was to evaluate the distribution and availability of the coastal driftwood in Italy and its impacts, as well as analyzing its chemical–physical properties to evaluate possible employment in combustion applications. On the basis of a data gathering campaign for the period 2010–2014, about 60,000 tons of driftwood are reported to accumulate along the Italian shores every year. The two regions hardest-hit were Liguria and Veneto, with about 15,000 tons and 12,000 tons, respectively. Three sites were selected for driftwood sampling. The main issue deriving from chemical characterization was the high chlorine content (up to 2% on dry basis) and metal oxides in the ashes. Driftwood samples were then subjected to a natural washing cycle for 1 month; results revealed a significant drop in chlorine and metal oxides contents (up to 80%) and a low decrease of the lower heating value (about 20%). Furthermore, the percolated water was analyzed in terms of chemical oxygen demand (COD), showing values (up to 1100 mg O 2 /L) above the Italian limits for discharges into surface waters

Embryonic rat dorsal root ganglia organotypic culture: a morphometric model to test neurotoxicology

Neurotoxicity is a common dose-limiting side-effect of several drugs (Cavaletti et al., 2008). So far a validated test method to screen drugs neurotoxicity does not exist, therefore in this interdepartment study we have analyzed the effectiveness of a morphometric neurotoxicty assessment model. Drug neurotoxicity evaluation is based on embryonic rat dorsal root ganglia (DRG) organotypic culture. DRG primary sensory neurons are the principal target of drugs neurotoxic action. In fact, primary sensory neurons lie outside the blood-nerve barrier and are supplied by capillaries with fenestrated walls. Moreover, the axons of these cells are among the longest of the entire nervous system and, therefore, are more susceptible to any agent that interferes with the energy metabolism or the structural basis of axonal transport. In particular, in this interdepartment study, the interference of the under study neurotoxic compound with NGF-induced neurite elongation is analysed. The effectiveness and reproducibility of this model, even if commonly used to test drugs, has not yet been demonstrated. In order to assess the validity of this in vitro model, antineoplastic drugs known to be in clinical use and in animal models neurotoxic (paclitaxel and oxaliplatin) or not dangerous (cyclophosphamide and 5-Fluorouracil) have been tested. DRGs explanted from E15 rat embryos have been treated for 24h with drugs concentrations comparable to those achievable in vivo. The length of the longest neurite of each DRG has been measured by ImageJ program. Experiments have been performed by three different blinded researchers in two different laboratories. Mean and standard deviation of each experiment were obtained, subsequently the mean value and standard deviation of the three independent experiments for each researcher were calculated. Data obtained by the three researchers in two different laboratories resulted statistically comparable and no significant differences were detected (One Way Anova analysis of variance and Tukey post test; p<0.05). This interdepartment in vitro study, therefore, indicates that a purely morphometric model represents a reliable tool to study drug neurotoxicity, permitting to make prediction of neurotoxic effects on humans because the concentrations tested are the same to which DRG are exposed during clinical use

Impact of remnant vital tissue after locoregional treatment and liver transplant in hepatocellular cancer patients. A multicentre cohort study

The role of pathological findings after locoregional treatments as predictors of hepatocellular cancer recurrence after liver transplantation has been poorly addressed. The aim of the study was to identify the role of remnant vital tissue (RVT) of the target lesion in predicting hepatocellular cancer recurrence. Two hundred and seventy-six patients firstly undergoing locoregional treatment and then transplanted between January 2010 and December 2015 in four European Transplant Centres (i.e. Rome Tor Vergata, Birmingham, Brussels and Ancona) were enrolled in the study to investigate the role of pathological response at upfront locoregional treatment. At multivariable Cox regression analysis, RVT ≥2 cm was a strong independent risk factor for post-LT recurrence (HR = 5.6; P < 0.0001). Five-year disease-free survival rates were 60.8%, 80.9% and 95.0% in patients presenting a RVT ≥2 cm vs. 0.1-1.9 vs. no RVT, respectively. When only Milan Criteria-IN patients were analysed, similar results were reported, with 5-year disease-free survival rates of 58.1%, 79.0% and 94.0% in patients presenting a RVT ≥2 cm vs. 0.1-1.9 vs. no RVT, respectively. RVT is an important determinant of tumour recurrence after liver transplantation performed for hepatocellular cancer. Its discriminative power looks to be evident also in a Milan-IN setting, suggesting to more liberally use locoregional treatments also in these patients