Terminal area guidance along curved paths: A stochastic control approach

Stochastic control theory is applied to the problem of designing a digital flight compensator for terminal guidance along a helical flight path as a prelude to landing. The development of aircraft, wind, and measurement models is discussed along with a control scheme consisting of feedback gains multiplying estimate of the aircraft and wind states obtained from a Kalman one step predictor. Preliminary results are presented which indicate that the compensator performs satisfactorily in the presence of both steady winds and gusts

The Very Low Head Turbine for hydropower generation in existing hydraulic infrastructures: State of the art and future challenges

The Very Low Head turbine (VLHT) is an axial flow turbine developed for heads below 4.5 m and flow rates up to 30 m3/s. In this work, the state of the art, the technological advancements and the scientific gaps were discussed and generalized, with a special focus on design, ecological behavior, costs, performance at different flows, heads and rotational speeds. The flow field and the hydraulic behavior under different configurations (e.g. in presence of cavitation and with an upstream obstacle) were described, with the aim of deriving engineering suggestions. Results of ecological tests were generalized (fish survival rate is more than 90%) by using the blade strike model, proposing an expeditious method for a preliminary appraisal of the ecological impact on downstream migrating fish. Despite the hundreds of installations worldwide, especially in existing barriers, some scientific gaps need to be better addressed yet, e.g., the influence of the number of blades and axis inclination on the efficiency, the influence of flow, head and rotational speed on the flow field and a quantification of the head losses through the trash rack above the runner

Parametric numerical solutions of additive manufacturing processes

Additive manufacturing is the more and more considered in industry, however efficient simulation tools able to perform accurate predictions are still quite limited. The main difficulties for an efficient simulation are related to the multiple scales, the multiple and complex physics involved, as well as the strong dependency on the process trajectory. In [21] authors proposed the use of advanced model reduction techniques for performing parametric simulations of additive manufacturing processes, where deposition trajectory, the intensity of the thermal shrinkage and the deposited layers were considered as model parameters. The resulting simulation tool allowed evaluating in real-time the impact of the parameters just referred on the part distortion, and proceed to the required geometrical compensation. In the present work we address the use of that parametric solution with three different purposes: (i) evaluating the parameters leading to the minimal part distortion; (ii) evaluating the solution sensitivity to the different parameters, and in particular to the ones related to the deposition trajectory; and (iii) propagating the uncertainty related to the intensity of the thermal shrinkage

Late recovery with cyclosporine-A of an auto-immune sudden sensorineural hearing loss

Sensorineural hearing loss of immune-mediated origin may be present as a symptom in systemic autoimmune diseases or may occur as a primary disorder without other organ involvement (auto-immune inner ear disease). The diagnosis of auto-immune inner ear disease is still predicated on clinical features and to date specific diagnostic tests are not available. We report a case of right-sided sudden hearing loss in a female patient in which the clinical manifestations, in addition to ANA positivity and hypocomplementaemia allowed us to hypothesize an auto-immune inner ear disease. The immunosuppressive treatment with cyclosporine-A was capable of a recovery of the hearing that, however, occurred progressively with normalization of the hearing function after 1 year of treatment. cyclosporine-A could be proposed as a therapeutic option in case of auto-immune inner ear disease allowing the suspension of corticosteroids that, at high dose, expose patients to potentially serious adverse events

Porphyrin-containing polyimide films deposited by high vacuum co-evaporation

Abstract Thin films of porphyrin-containing polyimide were produced by high vacuum co-evaporation of 4,4′-hexafluoroisopropylidene diphthalic anhydride (6FDA), 3,3′-diaminodiphenyl sulfone (DDS) and 5,10,15,20 meso-tetraphenyl porphyrin (TPP). The films were characterized by FT-IR analysis, optical absorption and emission spectroscopy. FT-IR analysis shows that the film matrix is comprised of only unreacted monomers. The conversion of monomers to polyamic acid and the following condensation to polyimide were studied by curing the samples at temperatures up to 240 °C. The amount of polyamic acid increases from room temperature to 120 °C, while at higher temperature it starts to condense to polyimide. Optical analysis shows that TPP is incorporated in the film matrix and its chemical state is determined by the interaction with the monomers, polyamic acid and polyimide. After curing the TPP molecules are finely dispersed in the polyimide matrix and their absorption and fluorescence properties are wholly preserved

Macro Asset Allocation with Social Impact Investments

Using a unique dataset of 50 listed companies that meet the majority of the OECD requirements for social impact investments, we construct a social impact finance stock index and investigate how investing in social impact firms can contribute to portfolio risk-return performance. We build portfolios with three different methodologies (naïve, Markowitz mean-variance optimization, GARCH-copula model), and we study the performance in terms of returns, Sharpe ratio, utility, and forecast premium based on a constant relative risk aversion function for investors with different levels of risk aversion. Consistent with the idea that social impact investment can improve portfolio risk-return performance, the results of our macro asset allocation analysis show the importance of a large fraction of investor portfolios’ stake committed to social impact investments

Reset dynamics and latching in niobium superconducting nanowire single-photon detectors

We study the reset dynamics of niobium (Nb) superconducting nanowire single-photon detectors (SNSPDs) using experimental measurements and numerical simulations. The numerical simulations of the detection dynamics agree well with experimental measurements, using independently determined parameters in the simulations. We find that if the photon-induced hotspot cools too slowly, the device will latch into a dc resistive state. To avoid latching, the time for the hotspot to cool must be short compared to the inductive time constant that governs the resetting of the current in the device after hotspot formation. From simulations of the energy relaxation process, we find that the hotspot cooling time is determined primarily by the temperature-dependent electron-phonon inelastic time. Latching prevents reset and precludes subsequent photon detection. Fast resetting to the superconducting state is therefore essential, and we demonstrate experimentally how this is achieved

A registry for the collection of data in cochlear implant patients

The need to optimize the use of all the information that modern technological tools have made available to the physician ENT/audiologist has increasingly emerged within the Italian scientific community. Towards this purpose, it is necessary to create a registry of the patients using cochlear implants (CIs). This registry will include a homogeneous summary of the information deriving from multiple sources related to daily clinical practice, in order to assess auditory benefits, safety and reliability in patients with cochlear implants, and organization over the national territory. The primary objectives relative to the above-mentioned analysis are to assess the impact of the use of cochlear implants on patient health, to ensure traceability of the devices currently used, monitoring their safety and reliability over time, to guarantee access of the technique in clinical and organizational conditions that can allow the best possible benefits. The aspects concerning implementation of the registry were discussed extensively during the first meetings of the Working Group (WG). In particular, owing to the complexity and high costs related mainly to the development of the technological aspects and the need to involve technological partners external to the WG, and to respect current privacy laws, the WG members decided that the project should be limited to proposal of a paper registry to be implemented at a later stage, possibly within the framework of successive research projects. During meetings, the WG members discussed various aspects of implementation of the registry, and in particular the scientific features connected to objectives, inclusion criteria, and structure of the forms needed for data collection and organizational aspects. A registry is proposed herein