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Tourism is the third largest socio-economic activity in the EU and thus it can be considered an engine for development, producing many positive impacts, from trade sector to employment. At the same time, it can produce many negative impacts because it is configured according to the model of linear economy. A deep analysis of impacts produced by tourism sector and its great potential in contributing to the achievement of SDGs are presented. The aim of this paper is to identify a tourism development/management model able to produce multidimensional benefits and, simultaneously, reduce (environmental, social and economic) costs. In this perspective, the circular economy is proposed as a model able to contribute to make tourism more sustainable. This model necessarily requires appropriate evaluation tools, indicators and knowledge. Aestimum, Aestimum 70 (2017)

Abstract The technical and economic feasibility of a single-stage water-sulphuric acid heat transformer, as evaluated through a simplified mathematical model, is discussed in this paper. Three different criteria of optimality are considered. The first two respectively account for the exergetic and the enthalpic value of the useful heat. The third criterion is based on an approximate evaluation of the fixed and operating costs, considered proportional to the inverse of the heat storage capacity. An analysis based on the values of the coefficient of performance and of the mass flow rates, expressed as a function of the gross temperature lift, points out the significance of the criterion based on the heat storage capacity. This result is also supported by considering the ability of the heat transformer to maintain its performance in different external conditions.

Abstract The stack represents the core of standing wave engines since inside it the thermal energy is converted into mechanical energy. Commonly stacks are realized with straight pores whose sections have regular shapes (e.g. circular, rectangular). In these cases the viscous and thermal interactions are described by well-known spatially averaged thermal and viscous functions. Instead, for a materials having tortuous pore, there is a lack in theoretical description of the thermoacoustic phenomenon. This paper deals with the performance of a thermoacoustic engine in which a tortuous porous material is used as stack. The spatially averaged thermal and viscous functions are obtained by classical models used to describe the sound propagation inside a porous material. In particular the Johnson–Champoux–Allard model is considered. It requires the knowledge of five parameters instead of the only hydraulic radius used to describe the standard stack having straight pores (e.g. circular, slit or square pores). The physical meaning of these parameters is explained starting from a straight circular pore and modifying, step by step, the shape of the pore until it becomes tortuous. The proposed functions have been included in the Rott theory and implemented in a numerical procedure. The achieved results are useful to analyse the thermoacoustic performance of a standing wave engine and to understand how the gain factor as well as the viscous and thermal losses inside the stack are affected by the tortuosity. A validation of this procedure is given by comparing the obtained results with ones given by DeltaEC software. This work can be useful to understand the applicability of tortuous porous materials, such as fibrous material as well as open-cell material, for standing wave thermoacoustic engines.

Italian harbours assume a decisive role in order to develop a Euro-Mediterranean web for maritime transportation. The geostrategic position of the Italian peninsula can be seen as a logistic platform at the centre of the maritime trades in the Mediterranean area, giving to its port cities the role of gateway of economic flows. The port poles, meant as hubs, are able to attract investments and create economic growth and territorial development through new operative models of urban usage and management. The management policies have to consider the environmental characteristics and distinctive features, respecting the identity of the places as concrete evidence of history, a source of intellectual development and therefore, cultural richness. In this sense, the current strategic plan “Palermo capital of the Euro-Mediterranean area” imagines the whole city, and not just its harbour, as a “gate city”, a sustainable and cosmopolitan city in the view of a recentralization of the Mediterranean area. The research tests an evaluation method in support of urban planning, which increases the active role of stakeholders in terms of participation and access to the decision-making process of urban renewal strategies for Palermo to the Euro-Mediterranean.

Abstract The attrition of limestone during calcination and sulfation in a fluidized bed reactor is modelled by taking into account the parallel occurrence of abrasion and gas-solid reaction. To this end, the particle is represented as a two-region domain over which equations expressing diffusion and reaction of gaseous reactants and calcium oxide depletion by reaction and attrition are written. Constitutive equations of different complexity are introduced to express the relationship between the attrition rate and the status of the particle surface. Experiments consisting of batchwise calcination and sulfation of limestone samples have been carried out in a bench-scale atmospheric bubbling fluidized bed reactor. Experimental data provided the basis for the evaluation of constitutive parameters and relationships to be embodied in the model. Model computations were directed towards reproducing experimental data points. In spite of its descriptive nature, the model provides useful insight into important features of the interactive processes of sorbent attrition and chemical reactions. First, calcium lost as elutriated fines is made almost entirely of attrited lime, the contribution of sulfate being limited. Second, attrition decays rapidly over a time scale depending on the parallel progress of particle round-off and lime sulfation. In particular, the progress of sulfation dramatically reduces attrition, presumably via the enhancement of particle connectivity and strength associated with the occurrence of ‘molecular cramming’. Third, the ability of attrition to enhance calcium utilization via the removal of impervious sulfate layers which build up at the particle surface is rather limited, at least with the sorbent and under the operating conditions considered in the work.

Human exposure to ionizing radiation is one of the acknowledged potential showstoppers for long duration manned interplanetary missions. Human exploratory missions cannot be safely performed without a substantial reduction of the uncertainties associated with different space radiation health risks, and the development of effective countermeasures. Most of our knowledge of the biological effects of heavy charged particles comes from accelerator-based experiments. During the 35th COSPAR meeting, recent ground-based experiments with high-energy iron ions were discussed, and these results are briefly summarised in this paper. High quality accelerator-based research with heavy ions will continue to be the main source of knowledge of space radiation health effects and will lead to reductions of the uncertainties in predictions of human health risks. Efforts in materials science, nutrition and pharmaceutical sciences and their rigorous evaluation with biological model systems in ground-based accelerator experiments will lead to the development of safe and effective countermeasures to permit human exploration of the Solar System.

A numerical model of cryo-maceration plant for mashed grapes has been realized to simulate the rapid cooling process for mashed grapes according to the number of nozzles enabled to inject CO2, to their flow and temperature of CO2 injected. ANSYS CFX program was used and two geometries have been considered with the axis of each nozzle orthogonal and parallel to the flow direction. Different boundary conditions have been considered. For the models have been considered the most burdensome condition.

Whether parenteral administration of reduced glutathione prevented ethanol induced damage to and depletion of sulfhydryl compounds in the human gastric mucosa was investigated. Ten healthy volunteers underwent endoscopy on three separate occasions. Gastric mucosal damage was induced by spraying 80% ethanol on to the gastric mucosa through the biopsy channel of the endoscope. The gastric mucosal score, total sulfhydryls, glutathione, and cysteine were evaluated in basal conditions and after ethanol administration with and without pretreatment with parenteral glutathione. Glutathione significantly decreased the extent of ethanol induced macroscopic injury to the mucosa of the gastric body and antrum. Glutathione's protective effect is associated with appreciable inhibition of ethanol induced depletion of gastric sulfhydryl compounds. This is the first report of protection against ethanol induced gastric mucosal damage by a sulfhydryl containing agent in humans.