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Low energy quantum regimes of 1D dipolar Hubbard model with correlated hopping
No full textWe apply the bosonization technique to derive the phase diagram of a balanced unit density two-component dipolar Fermi gas in a one dimensional lattice geometry. The considered interaction processes are of the usual contact and dipolar long-range density-density type together with peculiar correlated hopping terms which can be generated dynamically. Rigorous bounds for the transition lines are obtained in the weak coupling regime. In addition to the standard bosonization description, we derive the low energy phase diagram taking place when part of the interaction is embodied non-perturbatively in the single component Hamiltonians. In this case the Luttinger liquid regime is shown to become unstable with respect to the opening of further gapped phases, among which insulating bond ordered wave and Haldane phases, the latter with degenerate edge modes
Integrating Estimates at Completion with Cost Contingency Management
No full textForecasting the final cost based on Earned Value Management (EVM) data and managing cost contingency consumption in ongoing projects are typically considered by scholars and practitioners as two distinct duties of the project team. However, the managerial approach to cost contingency management may significantly impact on final cost performance. To this end, this paper proposes a theoretical model that considers different behaviors of cost contingency (CC) consumption to help forecast risk adjusted cost estimates at completion (CEAC). Three possible S-shaped growth profiles are proposed to represent three main categories of managerial attitudes in responding to project risk, namely: aggressive, neutral or passive CC consumption rates. Then, these curves are integrated into schedule-based CEAC prediction models, using nonlinear regression. An earned value management (EVM) dataset is used to show applicability and viability of the methodology. The paper is a contribution to bridging the gap between EVM and CC management. It provides project managers with a model to estimate the range of possible CEACs based on different risk attitudes
Differences in Mobility Among Older Adults are Associated with Motor Unit Activity and Muscle Strength
No full textDevelopment of new nanostructured electrodes in Microbial Fuel Cells (MFCs)
No full textThe aim of my thesis work is to investigate new nanostructured materials, obtained by the electrospinning technique, in order to design 3D arrangement of the electrodes, leading thus to improve the energy efficiency of energy production devices, such as microbial fuel cells (MFCs). The carbon nanofibers reveal to be the most promising material in the field of bio electrochemistry; in fact, up to now the best performing microbial fuel cells are fabricated using carbon and carbon based material electrodes. To further enhance the performances of bio anodes and bio cathodes, a set of properties are then required to be overcome, such as a proper surface morphology and chemistry, good biofilm adhesion and electron transfer, and a good electrical conductivity. This work aims to demonstrate that the electrospun nanofibers own all the necessary properties, revealing themselves as the most innovative and promising structures for anodes and cathodes for microbial fuel cells. The nanofibers ensure all the properties listed above; in particular, during my Ph.D. I have investigated and studied the carbon based nanofibers to be applied as cathode and as anode in these kind of the devices. In this thesis, it will be demonstrated that the nanostructured electrodes improve the efficiency devices thanks both to the low impedance and to the interaction with the microorganisms. The high micrometric porosity characteristics of the realized anodic material create the ideal habitat for the microorganism's proliferation. Moreover, different solution for the cathode material have been developed using ceramic nanofibers, such as MnxOy nanofibers and carbon nanofibers, in order to improve the performance of the devices. The layer made of these nanofibers, in fact, catalyzes the oxygen reduction reaction if the oxygen is used as terminal electron acceptor in the devices; thus these catalysts can substitute the platinum layer, which is the most used today, granting a cheaper and eco friendlier material
Estimation of joint position error
No full textJoint position error (JPE) is frequently used to assess proprioception in rehabilitation and sport science. During position-reposition tests the subject is asked to replicate a specific target angle (e.g. 30° of knee flexion) for a specific number of times. The aim of this study is to find an effective method to estimate JPE from the joint kinematic signal. Forty healthy subjects were tested to assess knee joint position sense. Three different methods of JPE estimation are described and compared using a hierarchical clustering approach. Overall, the 3 methods showed a high degree of similarity, ranging from 88% to 100%. We concluded that it is preferable to use the more user-independent method, in which the operator does not have to manually place "critical" markers
CULTURAL BUILT HERITAGE'S TANGIBLE & INTANGIBLE DIMENSIONS AND DIGITALIZATION CHALLENGES
No full textThis research is based on the ongoing debate on the strengths and challenges brought about by the so-called ‘digital revolution' in the field of the conservation of Cultural Built Heritage. Within this framework, this study analyses how the dynamic relationship between tangible and intangible heritage strongly affects the values of a site with consequent repercussions on the impacts of these values on conservation choices and actions. The complex relationships between tangible and intangible dimensions of cultural heritage have been, until recently, surprisingly underestimated in scientific research. A possible explanation lies in the limited amount of multidimensional and interdisciplinary approaches applied by scholars of different disciplines, often interested in more sectorial analysis of either the tangible or the intangible dimensions of cultural built heritage. The research moves in the direction of integrating such dimensions through a comprehensive approach. The project aims at demonstrating that an understanding of the role of intangible dimensions of built heritage can orient the conservation process, moving towards a more inclusive approach based on the respect for different context-based perspectives and interpretations of the cultural dimensions of heritage conservation, preservation and restoration
Use of biological mesh in trans-anal treatment for recurrent recto-urethral fistula
No full textPurpose: To report the author's experience on a miniinvasive technique using bioprosthetic plug and a rectal wall flap advancement in the treatment of recurrent rectourethral fistula. Materials and methods: Between 2013 and 2015, seven patients with recurrent recto-urethral fistula were referred to the Pederzoli Hospital, Peschiera del Garda, Verona,Italy. Intraoperatively all patients were found to have a rectal wall lesion and were treated with urinary and fecal diversion. For the persistence of the fistula, all the patients underwent a mini-invasive treatment consisting on placement of a bioprosthetic plug in the fistula covered by an endorectal advancement flap through a trans-anal and transurethral combined technique. Results: Median operative time was 48 min with a median blood loss of 30 ml. Median hospital stay was 3 days (IQR 1-3). No case of fistula recurrence or plug migration was described. None of the patients experienced fecal or urinary incontinence. All patients obtained complete fistula healing. Conclusions: Recurrent recto-urethral fistula is a challenging postsurgical complication for surgeons and urologists
Innovative Modelling Approaches for the Design, Operation and Control of Complex Energy Systems with Application to Underground Infrastructures
No full textThe ventilations systems play a key role in underground infrastructures for health and safety of occupants during normal operation as well as during accidents. Their performances are affected by selection of the optimal design, operation and control that is investigated by predicting air flow. The calculation of ventilation flows and their interaction with fires can be done with different modelling approaches that differ in the accuracy and in the required resources. The 3D computational fluid dynamics (CFD) tools approximate the flow behaviour with a great accuracy but they require high computational resources. The one dimensional (1D) models allow a compact description of the system with a low computational time but they are unsuitable to simulate thermal fluid-dynamic scenarios characterized by turbulence and gradients. Innovative tools are necessary in order to make the analysis and optimization of these systems possible and accurate in a reasonable time. This can be achieved both with appropriate numerical approaches to the full domain as the model order reduction techniques and with the domain decompositions methods as the multiscale physical decomposition technique. The reduced order mode techniques as the proper orthogonal decomposition (POD) is based on the snapshots method provides an optimal linear basis for the reconstruction of multidimensional data. This technique has been applied to non-dimensional equations in order to produce a reduced model not depending on the geometry, source terms, boundary conditions and initial conditions. This type of modelling is adapted to the optimization strategies of the design and operation allowing to explore several configuration in reduced times, and for the real time simulation in the control algorithms. The physical decomposition achieved through multiscale approaches uses the accuracy of the CFD code in the near field e.g. the region close to the fire source, and takes advantage of the low computational cost of the 1-D model in the region where gradients in the transversal direction are negligible. In last years, the multiscale approach has been proposed for the analysis of tunnel ventilation. Among the several CFD codes used in this field, the Fire Dynamic Simulator (FDS) is suitable for the multiscale modelling. This is an open source CFD package developed by NIST and VTT and presents the HVAC routine in which the conservation equations of mass, energy and momentum are implemented. Currently, the HVAC module does not allow one to consider heat and mass transfer, which significanltly limits the applications. For these reasons a multiscale simulator has been created through the fully integration of a 1D continuity, momentum, energy and mass transport equation in FDS modifying its source codes. The multiscale simulator thus obtained, is based on a direct coupling by means of a Dirichlet-Neumann strategy. At each 1-D-CFD interface, the exchange flow information occurs prescribing thermo-fluid dynamic boundary conditions. The 1-D mass transport equation computes the diffusion of the exhaust gas from the CFD domain and the relative concentration that is particularly interesting in the case of back layering of smoke. The global convergence of the boundary conditions at each 1-D-CFD interface has been analyzed by monitoring the evolution of thermo-fluid dynamic variables (temperature, velocity, pressure and concentration. The multiscale simulator is suitable for parametric and sensitivity studies of the design and the operation ventilation and fire safety systems. This new tool will be available for all the scientific community. In this thesis, Chapter 1 provides a general introduction to the role of the system ventilation in underground infrastructures and to the innovative modelling strategies proposed for these systems. Chapter 2 offers a description of the 1D network modelling, its fluid-dynamic application to the Frejus tunnel and its thermal application to ground heat exchangers. In Chapter 3, the proper orthogonal decomposition method is presented and its application to the optimal control of the sanitary ventilation for the Padornelo Tunnel is discussed. To demonstrate the applicability of POD method in other fields, boreholes thermal energy storage systems have been considered in same chapter. In particular, a multi-objective optimization strategy is applied to investigate the optimal design of these system and an optimization algorithm for the operation is proposed. Chapter 4 describes the multiscale approach and the relative simulator. The new open tool is used for modeling the ventilation system of the Monte Cuneo road tunnel in case of fire. Results show that in the case of the current configuration of the ventilation system, depending on the atmospheric conditions at portals, smoke might not be fully confined. Significant improvements in terms of safety conditions can be achieved through increase of in smoke extraction, which requires the installation of large dumpers and of deflectors on the jet fans. The developed tool shows to be particularly effective in such analysis, also concerning the evaluation of local conditions for people evacuation and fire-brigades operation
