New Seismic Attenuation System (SAS) for the Advanced LIGO Configurations (LIGO2)

A new passive seismic attenuation system is being developed to replace the current passive attenuation stacks in LIGO 2, it is expected to drive the seismic contribution to the interferometer noise below any other noise source. The SAS will be effective completely starting at about 5 Hz, well inside the (uncompensated) gravity gradient noise wall

Results of medium seventeen years' follow-up after laparoscopic choledochotomy for ductal stones

INTRODUCTION: In a previously published article the authors reported the long-term follow-up results in 138 consecutive patients with gallstones and common bile duct (CBD) stones who underwent laparoscopic transverse choledochotomy (TC) with T-tube biliary drainage and laparoscopic cholecystectomy (LC). Aim of this study is to evaluate the results at up to 23 years of follow-up in the same series. METHODS: One hundred twenty-one patients are the object of the present study. Patients were evaluated by clinical visit, blood assay, and abdominal ultrasound. Symptomatic patients underwent cholangio-MRI, followed by endoscopic retrograde cholangiopancreatography (ERCP) as required. RESULTS: Out of 121 patients, 61 elderly patients died from unrelated causes. Fourteen patients were lost to follow-up. In the 46 remaining patients, ductal stone recurrence occurred in one case (2,1%) successfully managed by ERCP with endoscopic sphincterotomy. At a mean follow-up of 17.1 years no other patients showed signs of bile stasis and no patient showed any imaging evidence of CBD stricture at the site of choledochotomy. CONCLUSIONS: Laparoscopic transverse choledochotomy with routine T-tube biliary drainage during LC has proven to be safe and effective at up to 23 years of follow-up, with no evidence of CBD stricture when the procedure is performed with a correct technique

Efficiency and maximal CP-asymmetry of scalar triplet leptogenesis

We study thermal leptogenesis induced by decays of a scalar SU(2)_L triplet. Despite the presence of gauge interactions, unexpected features of the Boltzmann equations make the efficiency close to maximal in most of the parameter space. We derive the maximal CP asymmetry in triplet decays, assuming that it is generated by heavier sources of neutrino masses: in this case successful leptogenesis needs a triplet heavier than 2.8 10^{10} GeV and does not further restrict its couplings, allowing detectable mu --> e gamma, tau --> mu gamma rates in the context of supersymmetric models. Triplet masses down to the TeV scale are viable in presence of extra sources of CP-violation.Comment: 12 pages, 6 figures. Interference term added to eq. (16d), figures recomputed (the difference is almost invisible

Student geographical mobility and labor market outcomes: evidences from Italy

The aim of this thesis is to discover the association between geographical mobility and labour markets outcomes of Italian early graduates. Even if is an argument widely trated in literature, I'll try to investigate the evolution of the \Brain Drain" process in light of recents event: the nancial crisis of 2007-2008 and the cut back in higher education. Migration decisions are closely related to degree of social mobilty in a country, especially where there are strong interregionals dierences as in Italy where, analyse migration path evolution of human capital might be very useful to policy makers intent to reduce regional gaps and improve the \equality of opportunity" level. Take into account migration endogeneity, the results suggest a positive eect of spatial mobility on economic performance with dierences according to movement trajectories. However some limits, due also to the lack of adequate data, indicate that further researchs are necessary in order to identify a causal relation. The thesis is strutured as follows: the rst chapter explains push and pull factros related to migration and the connection with social mobility, wage inequality and regional development. The chapter two presents an estimation of the return to geographical mobility of early graduates wages while the third chapter present the estimation of return from geographical mobility in terms of employment condition using a dataset summarizing information coming from three dierent sources: Almalaurea, Infostud and Ministry of Labor

Effects of pilot injection parameters on low temperature combustion diesel engines equipped with solenoid injectors featuring conventional and rate-shaped main injection

The potential of pilot injection has been assessed on a low-temperature combustion diesel engine for automotive applications, which was characterized by a reduced compression-ratio, high EGR rates and postponed main injection timings. Dwell time sweeps have been carried out for pilot injections with distinct energizing times under different representative steady-state working conditions of the medium load and speed area of the New European Driving Cycle. The results of in-cylinder analyses of the pressure, heat-release rate, temperature and emissions are presented. Combustion noise has been shown to decrease significantly when the pilot injected mass increases, while it is scarcely affected by the dwell time between the pilot and main injections. The HC, CO and fuel consumption trends, with respect to both the pilot injection dwell time and mass, are in line with those of conventional combustion systems, and in particular decreasing trends occur as the pilot injection energizing time is increased. Furthermore, a reduced sensitivity of NOx emissions to both dwell time and pilot injected mass has been found, compared to conventional combustion systems. Finally, it has been observed that soot emissions diminish as the energizing time is shortened, and their dependence on dwell time is influenced to a great extent by the presence of local zones with reduced air-to-fuel ratios within the cylinder. A combined analysis of the results of swirl sweeps and dwell time sweeps is here proposed as a methodology for the detection of any possible interference between pilot combustion burned gases and the main injected fuel. The effect of pilot injection on engine performance and emissions has also been assessed in the presence of rate-shaped main injections. These main injection profiles have been implemented with solenoid injectors by designing the injection fusion between a pre injection shot, which is added after the pilot injection, and the main injection. This innovative strategy shows benefits, with respect to combustion noise, although it still results in a reduced impact on NOx emissions. Furthermore, the brake specific fuel consumption and soot levels generally become worse than in the case of the simple pilot–main injection schedules. The injection fusion strategy has a significant impact on the soot versus dwell time dependence, which is influenced by the interference between the main injection and pilot combustion

Potential of double pilot injection strategies optimized with the design of experiments procedure to improve diesel engine emissions and performance

The potential of pilot–pilot–main triple injection strategies versus engine-out emissions, combustion noise and brake specific fuel consumption has been assessed experimentally on a Euro 5 diesel engine with a reduced compression ratio (16.3:1). The engine has been fueled with conventional diesel fuel. The experimental tests on the engine have been carried out in a dynamometer cell under different steady state working conditions, that are representative of passenger car engine applications over the European homologation cycle. Furthermore, in-cylinder analyses of the pressure, heat-release rate, temperature and emissions have been performed in order to obtain more detailed knowledge on the cause-and-effect-relationships between the implemented injection strategies and the results of the experimental tests. The implemented double-pilot injection engine calibrations have been optimized by means of the design of experiments procedure. The plotted data of the engine performance and emissions have been compared with data from the original double-injection schedule, characterized by a retarded main injection timing, in order to intensify the premixed combustion phase. The benefits and the disadvantages of the PCCI concept are preliminarily discussed, on the basis of the experimental pilot–main injection strategy results. The substitution of the pilot–main injection schedule with the triple injection, for light engine loads and low engine speeds, has led to higher mean combustion pressures, lower heat release rates, shorter ignition delays and lower brake specific fuel consumption. Above all, a significant improvement in engine noise and in both CO and HC engine-out emissions has been achieved and the NOx emission have been limited by the application of high EGR rates. When medium engine loads and speeds are analyzed, the considered double-pilot injection strategy allows the NOx emissions to be reduced, compared to the baseline pilot–main injection schedule. However, the combustion noise does not improve and the soot deteriorates, even though the soot penalties are not relevant

Data Exchange Processes for the Definition of Climate-Proof Design Strategies for the Adaptation to Heatwaves in the Urban Open Spaces of Dense Italian Cities

The growing awareness of the danger of extreme weather phenomena highlights the inadequacy of current cities and the increase in their level of vulnerability concerning the impacts resulting from climate change. The theme of design to combat climate impacts requires the development of knowledge and process models capable of managing the complexity of the information necessary to direct a climate-proof transformation of the urban systems. The research made it possible to develop a methodology based on the exchange of data between GIS-based ICT tools and for parametric design, to analyze the microclimatic and performance behavior of recurrent types of urban open spaces in Italian cities, characterized by different climatic conditions, through generic urban patterns, homogeneous in terms of building density and morphology. The goal achieved was to define the critical aspects of urban open spaces with the performance offered in response to the phenomenon of heatwaves, to verify and measure the performance effectiveness of climate-proof intervention categories, to transfer these results in the form of database, hazard maps, and potential levels of adaptation, and to define guidelines for the climate-oriented project. The transfer of the project data took place through a decision support webGIS platform (SDSS)

A note on the Kuramoto-Sivashinsky equation with discontinuity

In this work we consider differential equations of the type $$pm, u^{(k)}=f(u),$$ and study the extinction profile of their solutions. Emphasis is placed on the special case $-u^{(4)}=sign(u)$, which is related to the Kuramoto-Sivashinsky equation. In this case we describe in more detail the extinction phenomenon and prove a conjecture by Galaktionov and Svirshchevskii

Blow-up profile for solutions of a fourth order nonlinear equation

It is well known that the nontrivial solutions of the equation u¿(r)+¿u¿(r)+f(u(r))=0u¿(r)+¿u¿(r)+f(u(r))=0 blow up in finite time under suitable hypotheses on the initial data, ¿¿ and ff. These solutions blow up with large oscillations. Knowledge of the blow-up profile of these solutions is of great importance, for instance, in studying the dynamics of suspension bridges. The equation is also commonly referred to as extended Fisher–Kolmogorov equation or Swift–Hohenberg equation. In this paper we provide details of the blow-up profile. The key idea is to relate this blow-up profile to the existence of periodic solutions for an auxiliary equation