SOLUZIONE IN FORMA CHIUSA PER IL CALCOLO DELLE FREQUENZE NATURALI DI CILINDRI A PARETE SOTTILE E BORDI INCASTRATI

In questo lavoro si presenta un modello matematico che consente di calcolare in forma chiusa ed in maniera accurata le frequenze naturali dei gusci cilindrici circolari isotropi a parete sottile e bordi incastrati. L’equazione delle frequenze è stata determinata applicando il principio di Hamilton, mediante il metodo di Rayleigh, al sistema di equazioni indefinite del moto derivanti dalla versione di Reissner della teoria di Love, opportunamente modificata con le assunzioni di Donnell. La validazione del modello è stata effettuata mettendone a confronto i risultati sia con quelli derivanti dall’analisi modale realizzata agli elementi finiti, sia con dati sperimentali e teorici presenti in letteratura. Da tale confronto è emerso che il modello fornisce frequenze naturali molto accurate, analoghe a quelle ottenibili al FEM o per via numerica con altri modelli presenti in letteratura, ma, grazie all’approccio risolutivo utilizzato, le ottiene con equazioni esplicite in forma chiusa e quindi senza la necessità di implementare complesse risoluzioni di tipo numerico

Power Losses Minimization for Optimal Operating Maps in Power-Split HEVs: A Case Study on the Chevrolet Volt

The power-split architecture is the most promising hybrid electric powertrain. However, a real advantage in energy saving while maintaining high performance can be achieved only by the implementation of a proper energy management strategy. This requires an optimized functional design before and a comprehensive analysis of the powertrain losses after, which could be rather challenging owing to the constructive complexity of the power-split transmission, especially for multimode architecture with multiple planetary gearing. This difficulty was overcome by a dimensionless model, already available in the literature, that enables the analysis of any power-split transmission, even in full electric operation. This paper relies on this approach to find the operating points of the internal combustion engine and both electric machines which minimize the total power losses. This optimization is carried out for given vehicle speed and demanded torque, by supposing different scenarios in respect of the battery capability of providing or gathering power. The efficiency of the thermal engine and the electric machines is considered, as well as the transmission mechanical power losses. The aim is to provide a global efficiency map that can be exploited to extract data for the implementation of the most suitable real-time control strategy. As a case study, the procedure is applied to the multi-mode power-split system of the Chevrolet Volt

Experimental Model-Based Linearization of a S.I. Engine Gas Injector Flow Chart

Experimental tests previously executed by the authors on the simultaneous combustion of gasoline and gaseous fuel in a spark ignition engine revealed the presence of strong nonlinearities in the lower part of the gas injector flow chart. These nonlinearities arise via the injector outflow area variation caused by the needle impacts and bounces during the transient phenomena that take place in the opening and closing phases of the injector and may seriously compromise the air-fuel mixture quality control for the lower injection times, thus increasing both fuel consumption and pollutant emissions. Despite the extensive literature about the operation and modelling of fuel injectors, there are no known studies focused on the nonlinearities of the gas injector flow chart and on the way they can be reduced or eliminated. The authors thus developed a mathematical model for the prediction of mass injected by a spark ignition (S.I.) engine gas injector, validated through experimental data. The gas injector has been studied with particular reference to the complex needle motion during the opening and closing phases, which may strongly affect the amount of fuel injected. In this work, the mathematical model previously developed has been employed to study and determine an appropriate injection strategy in order to linearize the injector flow chart to the greatest degree possible. The injection strategy proposed by the authors is based on minimum injection energy considerations and may be easily implemented in current engine control units (ECU) without any hardware modification or additional costs. Once calibrated by means of simulation, this strategy has been validated by experimental data acquired on an appropriately equipped injector test bench. As a result, the real injector flow chart has been substantially improved, reducing its deviation from linearity to one third of the original flow chart, which is an excellent result, especially if the typical measurement dispersion of the injected mass is taken into account. The injection strategy proposed by the authors could extend the linear behaviour of gas injectors and improve the fuel supply by means of a simple software update of the ECU, thus obtaining higher engine efficiency and lower pollutant emissions

Approximate Closed-Form Solutions for the Shift Mechanics of Rubber Belt Variators

The mechanical behavior of V-belt variators during the speed ratio shift is different from the steady operation as a gross radial motion of the belt is superimposed to the circumferential motion. The theoretical analysis involves equilibrium equations similar to the steady case, but requires a re-formulation of the mass conservation condition making use of the Reynolds transport theorem. The mathematical model of the belt-pulley coupling implies the repeated numerical solution of a strongly non-linear differential system. Nevertheless, an attentive observation of the numerical diagrams suggests simple and useful closed-form approximations for the four possible working modes of any pulley, opening/closing, driver/driven, whose validity ranges over most practical cases. The present analysis focuses on the development of such simplified solutions, succeeding in an excellent matching with the numerical plots, and on the comparison of the theory with some experimental tests on a motorcycle variator, revealing a very good agreemen

Percutaneous mitral valve repair with the MitraClip system: acute results from a real world setting

This study sought to evaluate the feasibility and early outcomes of a percutaneous edge-to-edge repair approach for mitral valve regurgitation with the MitraClip((R)) system (Evalve, Inc., Menlo Park, CA, USA).Patients were selected for the procedure based on the consensus of a multidisciplinary team. The primary efficacy endpoint was acute device success defined as clip placement with reduction of mitral regurgitation to < 2+. The primary acute safety endpoint was 30-day freedom from major adverse events, defined as the composite of death, myocardial infarction, non-elective cardiac surgery for adverse events, renal failure, transfusion of > 2 units of blood, ventilation for > 48 h, deep wound infection, septicaemia, and new onset of atrial fibrillation. Thirty-one patients (median age 71, male 81%) were treated between August 2008 and July 2009. Eighteen patients (58%) presented with functional disease and 13 patients (42%) presented with organic degenerative disease. A clip was successfully implanted in 19 patients (61%) and two clips in 12 patients (39%). The median device implantation time was 80 min. At 30 days, there was an intra-procedural cardiac tamponade and a non-cardiac death, resulting in a primary safety endpoint of 93.6% [95% confidence interval (CI) 77.2-98.9]. Acute device success was observed in 96.8% of patients (95% CI 81.5-99.8). Compared with baseline, left ventricular diameters, diastolic left ventricular volume, diastolic annular septal-lateral dimension, and mitral valve area significantly diminished at 30 days.Our initial results with the MitraClip device in a very small number of patients indicate that percutaneous edge-to-edge mitral valve repair is feasible and may be accomplished with favourable short-term safety and efficacy results

Annual Progress Report of the European and Global Drought Observatories

With this report, the reader finds an overview of the changes, upgrades and new features created in the European Drought Observatory (EDO) and the Global Drought Observatory (GDO) and made in 2019. The year proved relatively quiet concerning drought events in Europe; the subcontinent was only affected in the Baltics, although fires broke out vigorously in the Balkans, Spain and Russia. Thanks to the recent juvenile concern with regard to the heating up of the climate, drought events and forest fires drew more public-attention. Our reaction upon this concern in the Global Drought Observatory is the development of a new group of data, which we call Drought Mitigation. With more people genuinely concerned in the effect of our alternation of the properties of the lower atmosphere, we take up the task to provide guidelines for repair and adaptation. Higher temperatures imply that air depletes more vapour from vegetation and soil, leading to more intense droughts or floods. Consient management of our fresh water resources and massive tree planting are measures that can have significant impact on the effects of a Drought, Forest Fires or also Flood events. Therefore, we started with including the results of the often-cited research result regarding reforestation potential of the Crowther Lab as a layer in the Global Drought Observatory. We completed our work with enriching data describing dams with data regarding the location, name and quantitative characteristics of dams as an additional layer. We worked on the integration of the GRACE Dataset, which gives us an actualized satellite born, insight in the depletion of groundwater resources. We created a new index, alerting drought impacts on protected wetlands. Droughts events in these areas might affect rare species living in these protected wetlands, thus creating a link to the biodiversity crisis. The drought alerting mechanism we developed thus far were human centred. With this new index and with the Crowther Lab reforestation inventory we hope to correct this one species view of the past, learning to share our territory with all species, also during hard times of a drought disaster. With these additions, we hope that EDO and GDO will give you a better overview of the impacts of drought events, not only for our economy but also for our shared ecosystems and their services to us. Finally note that we engage in a project to export EDO and GDO knowledge and software to African regional partners. Thus enabling them to set up drought observatories in Africa just as if we did for South- and Central America. Such a collaboration works both ways, we understand better the impacts of Drought events in their region and we learn from their practical skills with regard to make things work in a challenging environment, whilst we can give them working drought observatory software, practical manners to, almost, fully automate the filling and updating of the systems combined with our specific expertise on droughts build up in the last 12 years.JRC.E.1-Disaster Risk Managemen

Association between polymorphisms of TAS2R16 and susceptibility to colorectal cancer

Background: genetics plays an important role in the susceptibility to sporadic colorectal cancer (CRC). In the last 10 years genome-wide association studies (GWAS) have identified over 40 independent low penetrance polymorphic variants. However, these loci only explain around 1‑4% of CRC heritability, highlighting the dire need of identifying novel risk loci. In this study, we focused our attention on the genetic variability of the TAS2R16 gene, encoding for one of the bitter taste receptors that selectively binds to salicin, a natural antipyretic that resembles aspirin. Given the importance of inflammation in CRC, we tested whether polymorphic variants in this gene could affect the risk of developing this neoplasia hypothesizing a role of TAS2R16 in modulating chronic inflammation within the gut. Methods: we performed an association study using 6 tagging SNPs, (rs860170, rs978739, rs1357949, rs1525489, rs6466849, rs10268496) that cover all TAS2R16 genetic variability. The study was carried out on 1902 CRC cases and 1532 control individuals from four European countries. Results: we did not find any statistically significant association between risk of developing CRC and selected SNPs. However, after stratification by histology (colon vs. rectum) we found that rs1525489 was associated with increased risk of rectal cancer with a (Ptrend of = 0.0071). Conclusions: our data suggest that polymorphisms within TAS2R16 gene do not have a strong influence on colon cancer susceptibility, but a possible role in rectal cancer should be further evaluated in larger cohorts

mRNA PGC-1α levels in blood samples reliably correlates with its myocardial expression: study in patients undergoing cardiac surgery

et al.[Objective]: Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) is a transcriptional coactivator that has been proposed to play a protective role in mouse models of cardiac ischemia and heart failure, suggesting that PGC-1α could be relevant as a prognostic marker. Our previous studies showed that the estimation of peripheral mRNA PGC-1α expression was feasible and that its induction correlated with the extent of myocardial necrosis and left ventricular remodeling in patients with myocardial infarction. In this study, we sought to determine if the myocardial and peripheral expressions of PGC-1α are well correlated and to analyze the variability of PGC-1α expression depending on the prevalence of some metabolic disorders. [Methods]: This was a cohort of 35 consecutive stable heart failure patients with severe aortic stenosis who underwent an elective aortic valve replacement surgery. mRNA PGC-1α expression was simultaneously determined from myocardial biopsy specimens and blood samples obtained during surgery by quantitative PCR, and a correlation between samples was made using the Kappa index. Patients were divided into two groups according to the detection of baseline expression levels of PGC-1α in blood samples, and comparisons between both groups were made by chi-square test or unpaired Student’s t-test as appropriate. [Results]: Based on myocardial biopsies, we found that mRNA PGC-1α expression in blood samples showed a statistically significant correlation with myocardial expression (Kappa index 0.66, p<0.001). The presence of higher systemic PGC-1α expression was associated with a greater expression of some target genes such as silent information regulator 2 homolog-1 (x-fold expression in blood samples: 4.43±5.22 vs. 1.09±0.14, p=0.044) and better antioxidant status in these patients (concentration of Trolox: 0.40±0.05 vs. 0.34±0.65, p=0.006). [Conclusions]: Most patients with higher peripheral expression also had increased myocardial expression, so we conclude that the non-invasive estimation of mRNA PGC-1α expression from blood samples provides a good approach of the constitutive status of the mitochondrial protection system regulated by PGC-1α and that this could be used as prognostic indicator in cardiovascular disease.Grant from Sociedad Valenciana de Cardiología, 2013 to Óscar Fabregat-Andrés.Peer Reviewe

Climate change impacts and adaptation in Europe

The JRC PESETA IV study shows that ecosystems, people and economies in the EU will face major impacts from climate change if we do not urgently mitigate greenhouse gas emissions or adapt to climate change. The burden of climate change shows a clear north-south divide, with southern regions in Europe much more impacted, through the effects of extreme heat, water scarcity, drought, forest fires and agriculture losses. Limiting global warming to well below 2°C would considerably reduce climate change impacts in Europe. Adaptation to climate change would further minimize unavoidable impacts in a cost-effective manner, with considerable co-benefits from nature-based solutions.JRC.C.6-Economics of Climate Change, Energy and Transpor

Mapping and Assessment of Ecosystems and their Services: An EU ecosystem assessment

This report presents an ecosystem assessment covering the total land area of the EU as well as the EU marine regions. The assessment is carried out by Joint Research Centre, European Environment Agency, DG Environment, and the European Topic Centres on Biological Diversity and on Urban, Land and Soil Systems. This report constitutes a knowledge base which can support the evaluation of the 2020 biodiversity targets. It also provides a data foundation for future assessments and policy developments, in particular with respect to the ecosystem restoration agenda for the next decade (2020-2030). The report presents an analysis of the pressures and condition of terrestrial, freshwater and marine ecosystems using a single, comparable methodology based on European data on trends of pressures and condition relative to the policy baseline 2010. The following main conclusions are drawn: - Pressures on ecosystems exhibit different trends. - Land take, atmospheric emissions of air pollutants and critical loads of nitrogen are decreasing but the absolute values of all these pressures remain too high. - Impacts from climate change on ecosystems are increasing. - Invasive alien species of union concern are observed in all ecosystems, but their impact is particularly high in urban ecosystems and grasslands. - Pressures from overfishing activities and marine pollution are still high. - In the long term, air and freshwater quality is improving. - In forests and agroecosystems, which represent over 80% of the EU territory, there are improvements in structural condition indicators (biomass, deadwood, area under organic farming) relative to the baseline year 2010 but some key bio-indicators such as tree-crown defoliation continue to increase. This indicates that ecosystem condition is not improving. - Species-related indicators show no progress or further declines, particularly in agroecosystems. The analysis of trends in ecosystem services concluded that the current potential of ecosystems to deliver timber, protection against floods, crop pollination, and nature-based recreation is equal to or lower than the baseline value for 2010. At the same time, the demand for these services has significantly increased. A lowered potential in combination with a higher demand risks to further decrease the condition of ecosystems and their contribution to human well-being. Despite the wide coverage of environmental legislation in the EU, there are still large gaps in the legal protection of ecosystems. On land, 76% of the area of terrestrial ecosystems, mainly forests, agroecosystems and urban ecosystems, are excluded from a legal designation under the Bird and Habitat Directives. Freshwater and marine ecosystems are subject to specific protection measures under the Water Framework and Marine Strategy Framework Directives. The condition of ecosystems that are under legal designation is unfavourable. More efforts are needed to bend the curve of biodiversity loss and ecosystem degradation and to put ecosystems on a path to recovery. The progress that is made in certain areas such as pollution reduction, increasing air and water quality, increasing share of organic farming, the expansion of forests, and the efforts to maintain marine fish stocks at sustainable levels show that a persistent implementation of policies can be effective. These successes should encourage us to act now and to put forward an ambitious plan for the restoration of Europe’s ecosystems.JRC.D.3-Land Resource