NonLocal Systems of Balance Laws in Several Space Dimensions with Applications to Laser Technolog

For a class of systems of nonlinear and nonlocal balance laws in several space dimensions, we prove the local in time existence of solutions and their continuous dependence on the initial datum. The choice of this class is motivated by a new model devoted to the description of a metal plate being cut by a laser beam. Using realistic parameters, solutions to this model obtained through numerical integrations meet qualitative properties of real cuts. Moreover, the class of equations considered comprises a model describing the dynamics of solid particles along a conveyor belt

Coupling conditions for the 3x3 Euler system

This paper is devoted to the extension to the full $3\times3$ Euler system of the basic analytical properties of the equations governing a fluid flowing in a duct with varying section. First, we consider the Cauchy problem for a pipeline consisting of 2 ducts joined at a junction. Then, this result is extended to more complex pipes. A key assumption in these theorems is the boundedness of the total variation of the pipe's section. We provide explicit examples to show that this bound is necessary.Comment: 21 pages, 6 figure

Density based approach for collision risk computation

In February 2015 the satellite DMSP-F13 exploded in orbit producing 160 new trackable pieces of space debris. In the following days, operators assessed how the explosion affects the risk for their spacecraft, considering only debris objects larger than 10 cm. However, also smaller fragments are an important part of the debris population as any collision with objects larger than 1 mm may interfere with the spacecraft operation. The impact of a new fragmentation event considering also the presence of small fragments can be assessed by studying the fragment cloud in terms of its spatial density, applying the proposed method CiELO. Our formulation allows representing the long-term evolution of a large number of fragments with an analytical model based on the continuity equation. Moreover, it guarantees a limited computational effort compared to the standard approach of following each individual object. Once the cloud density is known, it is possible to build a collision map that identifies which are the most affected regions of space as a consequence of the breakup. Coupling this map with a database of spacecraft or space debris objects it is also possible to identify the most exposed targets. This kind of maps can be useful for operators to have a fast estimation of the increase in the long term collision risk on their mission

Revisiting the OECD Review of the Korean Health System

This paper follows up to the recommendations put forward by the OECD in 2003 in a review of the Korean health system, and analyses recent policy developments as well as areas for performance improvement. The Korean health system is characterised by a large role of the private sector in both the delivery and the financing of health services, and by predominant fee? for?service payments of health care providers. Despite significant achievements since the 1970s, such as the establishment of universal coverage in 1989, a relatively low share of GDP devoted to health spending, and unconstrained users’ freedom of provider choice, the Korean health system has faced significant policy challenges since 2000. At the start of the new millennium, difficulties in implementing two ambitious and controversial reforms??the merge of autonomous insurance societies into a single public payer and the separation of the functions of prescribing and dispensing of pharmaceuticals between doctors and pharmacists??were exacerbated by a financial crisis in the National Health Insurance system. More recently, Korea is addressing questions such as, among others: how should the health system respond to a rapidly ageing society; how could prevention be encouraged; how could access to care be preserved given significant out?of?pocket payments by households; what should be the role of private health insurance; what incentives and monitoring mechanisms for quality of care should be adopted; how could financial sustainability be maintained. Although the Korean health system is unique, the problems with which Korean health policy makers are wrestling will be familiar to other OECD countries

Europe and Contentious Cultural Heritages

This second issue of TRACES Journal has been designed as a dialogue among the scientific coordinators of some of the most recent European Union’s flagship research projects focusing on museums and heritage studies, including some recently concluded programmes as well as some newer researches launched under the H2020 umbrella. We called upon them to question what roles heritage can and should play to address social division and crisis in Europe. We asked them about the focus and the scope of their projects and their relevance in view of contemporary social, political and economic issues affecting Europe and its inhabitants; the expected impact of their research as well as the influence of EU political and funding agendas on the framing of their programme, its lines of enquiry and methods

On-site monitoring of the performance of innovative treatments for marble conservation in architectural heritage

Innovative nanostructured treatments for stone conservation, based on dispersions of photoactive TiO2 nanoparticles, recently studied in our research group, provided interesting results after laboratory testing. Unfortunately, it is almost impossible to accurately reproduce in the lab the complexity of field exposure conditions. It is then of crucial importance to evaluate the behaviour and durability of new treatments in situ, once they are applied to real deteriorated surfaces of the architectural heritage exposed in outdoor. In the present research, the effectiveness of a TEOS-nano-TiO2 treatment and of two nanocomposites based on nano-TiO2 dispersion in organosiloxane and functionalized SiO2 for the protection of two specific marbles—Candoglia and Crevoladossola—has been evaluated on-site. The effect of the introduction of innovative titania nanoparticles in selected commercial products has been examined focusing on compatibility and protection efficacy in real exposure condition. An on-site testing protocol has been defined and carried out for 12 months after the application, considering colour and morphology changes and water absorption by capillarity. The nano-TiO2 addition does not hinder the performance of the protective treatments while it provides a positive contribution in soiling reduction. The results will be implemented in the operative framework of the ongoing conservation project of the considered historical façade

A comprehensive aeroservoelastic approach to detect and prevent pilot assisted oscillations in tiltrotors

LAUREA MAGISTRALENei convertiplani, così come negli elicotteri e negli aeroplani, le vibrazioni strutturali del velivolo possono attivare la riposta biomeccanica involontaria del pilota, generando percorsi di carico potenzialmente critici in grado di deteriorare le prestazioni della macchina. Interazioni avverse tra pilota e velivolo possono provocare oscillazioni, determinare difficoltà nel completare una missione o, in ultima istanza, causare la perdita di controllo del sistema. Questi fenomeni di accoppiamento uomo-macchina sono noti in letteratura con la sigla PAO, acronimo di Pilot Assisted Oscillation. I PAO si verificano in una banda passante compresa tra 2 e 8 Hz, e richiedono accurate modellazioni aeroelastiche di un velivolo. È stato sviluppato un dettagliato modello del convertiplano Bell XV-15, comprensivo di una struttura elastica modellata a elementi finiti accoppiata ad una pannellatura aerodinamica in grado di rappresentare i carichi instazionari, rotori aeroelastici, drive-train, servo-attuatori e controllori. Il modello è elaborato in MASST, un software sviluppato in MATLAB dal Politecnico di Milano per analisi aeroservoelastiche e aeromeccaniche di aeroplani ed elicotteri ed attualmente utilizzato da industrie leader nella produzione di elicotteri. Le analisi di PAO sono effettuate introducendo dei modelli biomeccanici del pilota in retroazione al modello aeroservoelastico del velivolo. I modelli di pilota sono rappresentati da funzioni di trasferimento, disponibili in letteratura, che traducono l'azione del pilota sui comandi di stick longitudinale/ laterale e sulla leva del collettivo/potenza. La stabilità del sistema comprensivo di velivolo e pilota è analizzata mediante tecniche di stabilità robusta. In particolare, i margini di stabilità del sistema a ciclo chiuso sono quantificati utilizzando il criterio di Nyquist. Le analisi di PAO sono realizzate separatamente lungo gli assi longitudinale, laterale e verticale; in ciascuno dei tre casi si analizzano i meccanismi responsabili dell'innesco di potenziali instabilità, individuando le dinamiche critiche. Infine, a seguito dell'identificazione di eventuali PAO, sono discussi possibili metodi di prevenzione del fenomeno.In tiltrotors, as well as in helicopters and airplane, the structural vibrations of the aircraft can interact with the involuntary pilot's biodynamics causing inadvertent man-machine coupling phenomena. These events are known in literature as PAOs, acronym of Pilot Assisted Oscillations and can cause oscillatory or divergent motions, difficulty in performing the desired tasks, and, ultimately, loss of control. PAOs occur in a frequency range between 2 and 8 Hz and they require an accurate aeroservoelastic modelling of the vehicle. This work presents an effective approach to develop multidisciplinary aeroservoelastic models that can tackle this peculiar type of problems. A detailed tiltrotor model, representative of the Bell XV-15, has been built using the simulation tool MASST, developed at Politecnico di Milano for the aeroservoelastic and aeromechanical analysis of aircraft and rotorcraft. This model includes a finite element airframe structural model, airframe unsteady aerodynamics, aeroelastic rotors, drive-train, servo-actuators and controllers. Biomechanical models of the pilot are included in feedback loop to define the Pilot-Vehicle System (PVS). The pilot, acting on the power lever and on the control stick, is described using a transfer function that characterises the biodynamic feedthrough (BDFT), i.e. involuntary control inceptor motion caused by external accelerations transmitted to the pilot's body. With the introduction of the pilot, the system is studied using robust stability analysis techniques. The stability margins of the system are quantified using Nyquist's criterion. PAO analyses are conducted separately along the longitudinal, lateral and vertical axes. Once a PAO mechanism is identified, a model reduction is performed to detect the main dynamics and the most influential parameters that trigger the instability. Finally, possible means of prevention are investigated and their pros and cons are discussed

Highly transparent poly(2-ethyl-2-oxazoline)-TiO2 nanocomposite coatings for the conservation of matte painted artworks

A nanocomposite coating based on TiO2 nanoparticles and poly(2-ethyl-2-oxazoline) is used as consolidant of matte painted surfaces (temperas, watercolors, modern paintings). The aim of this work is to provide advances in the conservation of these works of art, while preserving their optical appearance, in terms of colour and gloss. Fiber Optic Reflectance Spectroscopy (FORS) measurements of a painting-model (an acrylic black monochrome) treated with the nanocomposite coatings revealed that it is possible to match the optical appearance of the painted surface by tuning the amount of nanoparticles in the polymeric matrix. The requirement of retreatability of the material has been verified by removing the nanocomposite cast on the painted surface with aqueous solutions. FTIR and SEM/EDX measurements showed that almost no traces of the nanocomposite remained on the painted surface, allowing its use for the treatment of real paintings. Test were performed using a contemporary studio-model on canvas attributed to Agostino Bonalumi (1935–2013)

IL-27, but not IL-35, inhibits neuroinflammation through modulating GM-CSF expression

IL-27 and IL-35 are heterodimeric cytokines, members of the IL-12 family and considered to have immunomodulatory properties. Their role during neuroinflammation had been investigated using mutant mice devoid of either one of their subunits or lacking components of their receptors, yielding conflicting results. We sought to understand the therapeutic potential of IL-27 and IL-35 delivered by gene therapy in neuroinflammation. We constructed lentiviral vectors expressing IL-27 and IL-35 from a single polypeptide chain, and we validated in vitro their biological activity. We injected IL-27 and IL-35-expressing lentiviral vectors into the cerebrospinal fluid (CSF) of mice affected by experimental neuroinflammation (EAE), and performed clinical, neuropathological and immunological analyses. Both cytokines interfere with neuroinflammation, but only IL-27 significantly modulates disease development, both clinically and neuropathologically. IL-27 protects from autoimmune inflammation by inhibiting granulocyte macrophages colony-stimulating factor (GM-CSF) expression in CD4+ T cells and by inducing program death-ligand 1 (PD-L1) expression in both CNS-resident and CNS-infiltrating myeloid cells. We demonstrate here that IL-27 holds therapeutic potential during neuroinflammation and that IL-27 inhibits GM-CSF and induces pd-l1 mRNA in vivo