The role of seasonal tourism in fragile territories : the case of Solanas, Sardinia

Since the post-war period Italy has been invested by an epochal phenomenon of redistribution of population, economies and urban materials from highlands to lowlands, from the hinterland to the coastline. Moreover, since the 1970s, the development of the Mediterranean coastal territories assumed a character strongly oriented to tourism too, altering the balance sedimented through the years in these areas, converting many slow landscapes into intermittent territories triggered by specifc seasons and monocultural activities. This proposal intends to refect on the possible development weaving the destinies of such realities, in the awareness that the reactivation of these territorial systems could be led by the rediscovery of connections and emergencies often forgotten, silent traces able to give back values to these tired landscapes. Working through interconnected territorial structures means to consider their networks and their tangible and intangible capital, and this is an indispensable exercise in order to rethink our country and some of its reiterated development models. Starting with a few days of interdisciplinary seminars that took place in between Politecnico di Torino and Politecnico di Milano, and the organisation of a workshop on-site, Solanas was identifed as an emblematic case, a valley able to explore these issues. Located in the south of Sardinia, annexed to the territory of Sinnai due to its ancient transhumance role, today it remains detached from the main inhabited centres, suffering strong isolation from welfare systems during the low season, and the exploitation of landscape resources because of mere tourist purposes during the high season. This condition of seasonal contraction, unfortunately rarely accompanied by a medium-long term planning, can be retraced along many other coastal areas of Mediterranean countries, becoming a specifc fragility of our reality to take into consideration

Urban freight distribution and innovative last-mile solutions from a traffic perspective

Urban population growth, the rise of e-commerce, and the increased need for economically and environmentally sustainable solutions represent urban freight distribution’s biggest challenges. Traffic and city logistics are often two sides of the same coin, as congestion affects city freight movements and vice versa. For this reason, it is important to develop comprehensive mobility and traffic management solutions that consider both systems. During the last decade, technology improvements in wireless communication, computational and sensing technologies, have paved the way to a series of mobility and transportation options (e.g., crowdshipping and driverless vehicles) that could transform the landscape of last-mile delivery. The main contribution of this dissertation consists of modeling urban freight impacts on traffic and investigating the potential implications of innovative last-mile solutions. The first part of this dissertation focuses on the feedback between freight movements and traffic, taking into consideration the impact of passenger vehicles on commercial vehicles, and vice versa. In order to achieve this goal, it is necessary to model trucks’ movements and loading/unloading operations with ad-hoc traffic simulations. Most of existing research has focused on analytical, static, or microscopic models, that either lack accuracy or scalability. Hence, this dissertation creates algorithms that couple existing macroscopic traffic flow models with the microscopic behavior of delivery vehicles. This issue is investigated both at single-link and network levels, by means of a suitable simulation framework. In both cases, applications of the modeling approach for freight traffic and freight demand management are shown. In the second part of this dissertation the potential impacts of last-mile delivery solutions are evaluated using the developed simulation framework. First, the impacts of alternative City Logistics solutions, such as off-peak deliveries and access restrictions are investigated. Then, the developed modeling framework is extended to investigate a crowdsourced service for parcel deliveries. The effects on traffic and emissions are investigated for the adoption of crowdshipping by carriers delivering parcels in the city center of Rome, Italy. The externalities associated with several strategic (chosen mode) and operational (detour length, parking behavior, and traffic conditions) aspects of this service are analyzed by means of simulation in realistic settings. Some results allow preliminary considerations about the effects of last-mile delivery solution that can been confirmed in other studies. Other findings, instead, are in line with studies from previous literature that adopted different approaches. The practice of off-peak deliveries, consisting in shifting part of the trips and operations to less congested hours of the day (typically evening and night) has proved to be an effective solution to freight-related congestion in urban settings. Restricting from deliveries specific links or sets of links, instead, could be beneficial only in some situations. Alternative crowdshipping implementation features, such as the transportation mode choice, but also operational aspects (such as availability of parking, optimization of existing trips, and implementation during off-peak hours) can also considerably influence the final traffic and emissions impacts of this service.Civil, Architectural, and Environmental Engineerin

An extended version of an algebraic intermittency model for prediction of separation-induced transition at elevated free-stream turbulence level

An algebraic intermittency model for boundary layer flow transition from laminar to turbulent state, is extended using an experimental data base on boundary layer flows with various transition types and results by large eddy simulation of transition in a separated boundary layer. The originating algebraic transition model functions well for bypass transition in an attached boundary layer under a moderately high or elevated free-stream turbulence level, and for transition by Kelvin–Helmholtz instability in a separated boundary layer under a low free-stream turbulence level. It also functions well for transition in a separated layer, caused by a very strong adverse pressure gradient under a moderately high or elevated free-stream turbulence level. It is not accurate for transition in a separated layer under a moderately strong adverse pressure gradient, in the presence of a moderately high or elevated free-stream turbulence level. The extension repairs this deficiency. Therefore, a sensor function for detection of the front part of a separated boundary layer activates two terms that express the effect of free-stream turbulence on the breakdown of a separated layer, without changing the functioning of the model in other flow regions. The sensor and the breakdown terms use only local variables

A Fast Autotuning Method for Velocity Control of Mechatronic Systems

In this paper a fast automatic tuning methodology for velocity controllers of mechatronic systems is proposed. In order to be applicable in general, the method takes into account the position, velocity and torque constraints of the motion control system and it requires a minimum intervention of the operator. Further, it can be implemented also with small computational capabilities which makes it suitable for industrial drives. Simulation results show the effectiveness of the technique

Time resolved PIV measurements of the unsteady wake migration in a LPT blade passage: effect of the wake passing frequency

A time resolved Particle Image Velocimetry (TR-PIV) system has been employed to investigate the unsteady propagation of upstream wakes in a low-pressure turbine cascade. Data are obtained in the steady state condition and for two passing wake reduced frequencies. The study is focused on the identification and split of the different dynamics responsible for deterministic and random oscillations, thus loss generation. A very large data set has been collected: for each condition, about 9000 instantaneous flow fields have been acquired at up to 2kHz in order to resolve with great detail the vortex shedding phenomenon characterizing the separation at steady condition as well as the propagation of the coherent structures induced by the incoming wake. Instantaneous vector maps, phase averaged velocity fields and Proper Orthogonal Decomposition (POD) have been used for the in depth characterization of the different phenomena. The paper takes advantage of the properties of POD that reduces the data set to a low number of modes that represent the most energetic dynamics of the system. It is clearly shown that the phase averaged flow field can be represented by a few number of POD modes related to the wake passing event for the unsteady cases. POD is also able to capture flow features affecting the instantaneous flow field not directly related to the wake passage (i.e. the vortex shedding phenomenon induced by the intermittent separation developing between adjacent wakes), that are smeared out in the phase averaged results. Once recognized the POD modes most involved in the unsteady flow field, a procedure for the quantification of the different contributions to the overall amount of losses is proposed

CarPatch: A Synthetic Benchmark for Radiance Field Evaluation on Vehicle Components

Neural Radiance Fields (NeRFs) have gained widespread recognition as a highly effective technique for representing 3D reconstructions of objects and scenes derived from sets of images. Despite their efficiency, NeRF models can pose challenges in certain scenarios such as vehicle inspection, where the lack of sufficient data or the presence of challenging elements (e.g. reflections) strongly impact the accuracy of the reconstruction. To this aim, we introduce CarPatch, a novel synthetic benchmark of vehicles. In addition to a set of images annotated with their intrinsic and extrinsic camera parameters, the corresponding depth maps and semantic segmentation masks have been generated for each view. Global and part-based metrics have been defined and used to evaluate, compare, and better characterize some state-of-the-art techniques. The dataset is publicly released at https://aimagelab.ing.unimore.it/go/carpatch and can be used as an evaluation guide and as a baseline for future work on this challenging topic.Comment: Accepted at ICIAP202

Effects of the combination between selected phytochemicals and the carriers silica and Tween 80 on dry matter and neutral detergent fibre digestibility of common feeds

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Modelling the effects of reaction temperature and flow rate on the conversion of ethanol to 1,3-butadiene

A full factorial experimental design was performed to investigate the conversion of ethanol to 1,3-butadiene (1,3-BD), through manipulation of the reaction temperature and ethanol weight hourly space velocity. Reactions were carried out in presence of the catalyst K2O:ZrO2:ZnO/MgO-SiO2, prepared by co-precipitation methods. Mathematical models were developed to correlate observed product selectivities, 1,3-BD yields and productivities with the manipulated reaction variables, allowing for quantification of variable effects on catalyst activity and assessment of the kinetic mechanism. Obtained 1,3-BD productivities were as high as 0.5gBD/gcat h,gBD/gcat h, with 1,3-BD yields of 27%. Results suggest that acetaldehyde condensation is the rate determining step

Ethanol to 1,3-butadiene conversion by using ZrZn-containing MgO-SiO₂ systems prepared by co-precipitation and effect of catalyst acidity modification

The conversion of ethanol to 1,3-butadiene (1,3-BD) has been investigated over ZrO2- and ZnO-containing magnesia silica oxides prepared by a co-precipitation method at different Mg-to-Si molar ratios. The effect of reaction temperature and ethanol flow rate was investigated. The catalyst acidity was modified through the addition of alkali metals (Na, K and Li) to the final materials. Catalysts were characterised by nitrogen physisorption analysis, X-ray diffraction, scanning electron microscopy with energy dispersive X-ray, temperature-programmed desorption of ammonia, infrared spectroscopy and 29Si/(7Li) NMR spectroscopy. The catalytic results showed that the controlled reduction of catalyst acidity allows ethanol dehydration to be suppressed, whilst increasing 1,3-BD selectivity. The best catalytic performance achieved 72 mol % for the combined 1,3-BD and acetaldehyde selectivity

Microkinetic analysis of ethanol to 1,3-butadiene reactions over MgO-SiO₂ catalysts based on characterization of experimental fluctuations

Microkinetic analysis of ethanol to 1,3-butadiene reactions over MgO-SiO2 catalysts was performed based on the detailed characterization of experimental fluctuations, taking into account the influence of the reaction temperature and catalyst properties on ethanol conversion and product selectivities. The obtained results show that both reaction temperature and catalysts properties affected experimental fluctuations significantly. The local microkinetic information contained in the covariance matrix of experimental fluctuations indicated the change of the rate-limiting step as reaction temperature increased: from 300 to 400 ºC, the rate-limiting step was identified as the acetaldehyde condensation, while at 450 ºC, ethanol dehydrogenation step limits the 1,3-butadiene production