Evolution of Configurations of Evaporative Systems for Seawater Desalination

La tesi presenta lo sviluppo e la validazione di modelli matematici delle tecnologie evaporative di desalinizzazione MSF, MED, MED-TVC e MED-MVC, il cui funzionamento è poi simulato in diverse condizioni di progetto. Viene poi illustrato un approccio innovativo per l'analisi exergetica delle suddette tecnologie, introducendo una nuova definizione di fuel e prodotto exergetici sulla base dello scopo produttivo del sistema.openEmbargo temporaneo per motivi editorial

High energy density storage of gaseous marine fuels: An innovative concept and its application to a hydrogen powered ferry

The upcoming stricter limitations on both pollutant and greenhouse gases emissions represent a challenge for the shipping sector. The entire ship design process requires an approach to innovation, with a particular focus on both the fuel choice and the power generation system. Among the possible alternatives, natural gas and hydrogen based propulsion systems seem to be promising in the medium and long term. Nonetheless, natural gas and hydrogen storage still represents a problem in terms of cargo volume reduction. This paper focuses on the storage issue, considering compressed gases, and presents an innovative solution, which has been developed in the European project GASVESSEL\uae that allows to store gaseous fuels with an energy density higher than conventional intermediate pressure containment systems. After a general overview of natural gas and hydrogen as fuels for shipping, a case study of a small Roll-on/Roll-off passenger ferry retrofit is proposed. The study analyses the technical feasibility of the installation of a hybrid power system with batteries and polymer electrolyte membrane fuel cells, fuelled by hydrogen. In particular, a process simulation model has been implemented to assess the quantity of hydrogen that can be stored on board, taking into account boundary conditions such as filling time, on shore storage capacity and cylinder wall temperature. The simulation results show that, if the fuel cells system is run continuously at steady state, to cover the energy need for one day of operation 140 kg of hydrogen are required. Using the innovative pressure cylinder at a storage pressure of 300 bar the volume required by the storage system, assessed on the basis of the containment system outer dimensions, is resulted to be 15.2 m3 with a weight of 2.5 ton. Even if the innovative type of pressure cylinder allows to reach an energy density higher than conventional intermediate pressure cylinders, the volume necessary to store a quantity of energy typical for the shipping sector is many times higher than that required by conventional fuels today used. The analysis points out, as expected, that the filling process is critical to maximize the stored hydrogen mass and that it is critical to measure the temperature of the cylinder walls in order not to exceed the material limits. Nevertheless, for specific application such as the one considered in the paper, the introduction of gaseous hydrogen as fuel, can be considered for implementing zero local emission propulsion system in the medium term

Circular Polarization of the Astrophysical Gravitational Wave Background

The circular polarization of gravitational waves is a powerful observable to test parity violation in gravity and to distinguish between the primordial or the astrophysical origin of the stochastic background. This property comes from the expected unpolarized nature of the homogeneous and isotropic astrophysical background, contrary to some specific cosmological sources that can produce a polarized background. However, in this work we show that there is a non-negligible amount of circular polarization also in the astrophysical background, generated by Poisson fluctuations in the number of unresolved sources, which can be detected by the third-generation interferometers with signal-to-noise ratio larger than one. We also explain in which cases the gravitational wave maps can be cleaned from this extra source of noise, exploiting the frequency and the angular dependence, in order to search for signals from the early Universe. Future studies about the detection of polarized cosmological backgrounds with ground- and space-based interferometers should account for the presence of such a foreground contribution.Comment: 10 pages, 1 figure. V2 matches the version accepted by PRL for publicatio

Adiabatic or Non-Adiabatic? Unraveling the Nature of Initial Conditions in the Cosmological Gravitational Wave Background

The non-thermal nature of the stochastic gravitational-wave background of cosmological origin (CGWB) poses a challenge in defining the initial conditions for the graviton overdensity. Specifically, the adiabatic initial condition, which holds for Cosmic Microwave Background (CMB) photons, is not guaranteed a priori for the primordial GWs. In this letter, we compute the initial conditions for the cosmological background generated by quantum fluctuations of the metric during inflation. Our analysis reveals that adiabatic initial conditions are no longer valid. The violation of adiabaticity arises from the presence of independent tensor perturbations during inflation, which behave as two extra fields that affect the standard single-clock argument. Since the energy density of the CGWB is subdominant compared to ordinary matter, gravitational radiation plays a negligible role in Einstein's equations. Therefore, the only way to compute the initial conditions is to perturb the energy-momentum tensor defined in terms of the gravitational strain. A direct consequence of our finding is that the initial conditions from inflation enhance the total CGWB angular power-spectrum by an order of magnitude compared to the standard adiabatic case.Comment: 7 pages, 1 figur

Robot-aided therapy for upper limbs in patients with stroke-related lesions. Brief report of a clinical experience

This study was aimed at verifying the improvement on the motor impairment and functionality in 19 patients with chronic hemiparesis after stroke treated with a robot-aided rehabilitation protocol using the ReoGo™ system (Motorika Medical Ltd, Israel), and at evaluating the persistence of the effects after 1 month. The study also focused on the actual possibility of administering the robot-aided therapy with the ReoGo™ for the upper limbs and on the patients' degree of acceptance and compliance with the treatment. Subjects underwent an assessment prior to the start of the rehabilitation project (T-1), one at the start (T0), one at the end of the treatment (T1) and one after one month from the end of the treatment (T2). The following tests were administered: (i) Fugl-Meyer (FM) upper limb; Ashworth scale (AS); Functional Independence Measure (FIM™) (T-1 - T2); (ii) strength evaluation; Visual Analogue Scale (VAS) for pain; Frenchay Arm test (FAT); Box and Block test (BBT); Timed Up and Go (TUG) test (T0 - T2). Additionally, the Euro-QoL questionnaire and a VAS for the treatment satisfaction were administered to the subjects. Non-statistical difference of scores at T-1 and T0 on almost the entire battery of tasks suggested a stable patients' performance prior to the start of the rehabilitation. With the exception of the Medical Research Council (MRC) and the AS sub-scales measuring -as appropriate- strength and spasticity of the shoulder, triceps and wrist, all scores showed a significant increase between T0 and T1. The improvement on the pain could not be proved significant (p = 0.10). A significant increase between T0 and T2 was found for all assessment scores, with the exception of the MRC for external shoulder rotators (p = 0.05) and of the AS for shoulder (p = 0.32) and wrist (p = 0.08). Substantial stability was observed between T1 and T2. Patients were capable of completing the treatment and showed good participant satisfaction. This pilot study led to the finding of a clinical improvement and excellent patients compliance. It is possible that the learning process experienced by the patients was robot-dependent, especially in consideration of the general maintenance of the achievements observed on all activities

GW_CLASS: Cosmological Gravitational Wave Background in the Cosmic Linear Anisotropy Solving System

The anisotropies of the Cosmological Gravitational Wave Background (CGWB) retain information about the primordial mechanisms that source the gravitational waves and about the geometry and the particle content of the universe at early times. In this work, we discuss in detail the computation of the angular power spectra of CGWB anisotropies and of their cross correlation with Cosmic Microwave Background (CMB) anisotropies, assuming different processes for the generation of these primordial signals. We present an efficient implementation of our results in a modified version of CLASS which will be publicly available. By combining our new code GW_CLASS with MontePython, we forecast the combined sensitivity of future gravitational wave interferometers and CMB experiments to the cosmological parameters that characterize the cosmological gravitational wave background.Comment: 64 pages, 16 figures. V2 matches the version published by JCAP. GW_CLASS is publicly available on the class_public git repository as a branch GW_CLASS, https://github.com/lesgourg/class_public/tree/GW_CLASS (For details on installation and usage, follow the instructions in the README.

Surgical treatment in patient with non-small-cell lung cancer with fissure involvement: Anatomical versus nonanatomical resection

OBJECTIVE: Despite the intense debate concerning the prognostic impact of fissure involvement (FI) in patients with non-small-cell lung cancer, no specific surgical strategies have been yet recommended when this condition occurs. In this setting, we report our monocentric 10-years experience to investigate this issue. METHODS: From January 2000 to January 2010, the clinical data of 40 non-small-cell lung cancer patients with FI undergoing curative resection were retrospectively reviewed. The sample was stratified according to the type of resection: group A (28 patients): anatomical resection (bilobectomy [21 patients], pneumonectomy [7 patients]); group B (12 patients): nonanatomical resection (lobectomy plus wedge resection [LWR]). The end-points were (1) impact of different surgical approach on the pulmonary function (measured before surgery and 1 month after discharge); (2) disease-specific survival; and (3) tumor recurrence.The t test, χ, and log-rank tests, Kaplan-Meier method, and Cox and logistic regression analyses were used for the statistical analysis. RESULTS: No differences between the two groups were found when comparing the clinical characteristics, histology, pN or pT status, p-stage, residual (R1) disease, tumor grading, or tumor size. Similarly, the baseline preoperative function (tested as forced expiratory volume in 1 second-%-predicted, FEV1%) was likewise comparable (92.5% ± 21.0% in group A versus 85.2% ± 20.0% in group B; p = not significant). The decline of FEV1% after surgery was slightly higher in group A (-24.9% ± 13.5%) when compared with that in group B (-19.5% ± 13.3%), but this difference was not statistically significant (p = ns). Nevertheless, the 5-year disease-specific survival was 56% for group A and 47% for group B (p = ns). The recurrence rate did not differ between the patients undergoing a LWR (3 of 12 patients) and those undergoing a bilobectomy or pneumonectomy (9 of 28 patients) (p = ns). The presence of FI extended for more than 3 cm was found to be the most significant prognostic factor when analyzing survival (p = 0.002) and recurrence rate (p< 0.001). CONCLUSIONS: Our results suggest that nonanatomical resection (LWR) could be considered as a feasible surgical option (especially in "frail" patients with an extent of FI less than 3 cm) in the light of the similar oncological and functional outcome compared with anatomical resection. Further studies based on larger series are needed to confirm these preliminary data and also to investigate the impact on the postoperative quality of life

Arf6 controls retromer traffic and intracellular cholesterol distribution via a phosphoinositide-based mechanism

Small GTPases play a critical role in membrane traffic. Among them, Arf6 mediates transport to and from the plasma membrane, as well as phosphoinositide signalling and cholesterol homeostasis. Here we delineate the molecular basis for the link between Arf6 and cholesterol homeostasis using an inducible knockout (KO) model of mouse embryonic fibroblasts (MEFs). We find that accumulation of free cholesterol in the late endosomes/lysosomes of Arf6 KO MEFs results from mistrafficking of Niemann–Pick type C protein NPC2, a cargo of the cation-independent mannose-6-phosphate receptor (CI-M6PR). This is caused by a selective increase in an endosomal pool of phosphatidylinositol-4-phosphate (PI4P) and a perturbation of retromer, which controls the retrograde transport of CI-M6PR via sorting nexins, including the PI4P effector SNX6. Finally, reducing PI4P levels in KO MEFs through independent mechanisms rescues aberrant retromer tubulation and cholesterol mistrafficking. Our study highlights a phosphoinositide-based mechanism for control of cholesterol distribution via retromer

post operative rehabilitation for surgically resected non small cell lung cancer patients serial pulmonary functional analysis

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