Inverse estimation of the local heat transfer coefficient in curved tubes: a numerical validation

Wall curvature represents one of the most used passive techniques to enhance convective heat transfer. The effectiveness of wall curvature is due to the fact that it gives origin to the centrifugal force: this phenomenon induces local maxima in the velocity distribution that locally increase the temperature gradients at the wall by then maximizing the heat transfer. This fact brings to a significant variation of the wall temperature and of the wall heat flux along the circumferential coordinate. The convective heat transfer coefficient is consequently not uniformly distributed along the tube's perimeter and is characterized by higher values at the extrados wall surface in comparison to the ones at the intrados wall surface. Therefore, for predicting the overall performance of heat transfer apparatuses that involve the use of curved tubes, it becomes important to know the local distribution of the convective heat transfer coefficient not only along the axis of the heat transfer section, but also on the internal tube's surface along the cross section circumference. The present paper is intended to the assessment of a procedure developed to evaluate the local convective heat transfer coefficient, along the circumferential coordinate, at the internal wall of a coiled pipe

DISPOSAL AND RECYCLING PROCESS FOR END OF LIFE SILICON PV MODULES: FEASIBILITY OF A PLANT BUILT IN ITALY

The disposal and recycling processes of waste electrical and electronic equipment (WEEE) have assumed an increasing importance during the last years, as confirmed by the rapidly growing waste stream experienced in particular in 2010: in fact, in Italy the collection target of four kilograms per annum per inhabitant has been achieved. Also Photovoltaic Modules, as their disposal has not been regulated yet, are included within WEEE. Since the promulgation of the Ministry for Economic Development Decree referring to the Fourth Feed in Tariff on May 5, 2011, the attention to this issue has increased. Moreover, this problem will become even more important in the next years, due to the wide spread of the photovoltaic technology, promoted by government incentives. In the present paper the feasibility of an end of life silicon PV modules recycling plant, built in Italy, was studied. Recycling processes have already been used in Germany, a country leader in the utilization of renewable energy resources, and the only one where an infrastructure of this type operates on industrial scale. Waste stream, capital, process and logistics costs were the basic parameters taken into account in order to define the economic feasibility of this method

NUMERICAL 2-D MODELING OF A COAXIAL SCRAPED SURFACE HEAT EXCHANGER VERSUS EXPERIMENTAL RESULTS UNDER THE LAMINAR FLOW REGIME

Scraped surface heat exchangers (SSHEs) provide a versatile solution in the process industry for treating highly viscous fluids that may also contain particulate matter. Although SSHEs are frequently used in industrial applications, literature on this topic, particularly on the laminar flow regime, is limited. Moreover, due to the specificity of each product, it is difficult to generalize the few data available, and this makes the thermal design of this type of apparatus a critical point. Regarding the numerical approach, several studies based on a two-dimensional (2-D) approximation are available in the open scientific literature, but there is a lack of experimentally validated models. To test the numerical modeling approach, an experimental investigation that focused on the behavior of a coaxial SSHE in the presence of laminar flow was conducted. The appropriateness of the 2-D numerical approach is discussed here. Comparison of the numerical results with the experimentally measured Nusselt number values demonstrates the limits of the 2-D approach in describing the behavior of this type of apparatus

NUMERICAL MODELLING OF A SCRAPED SURFACE HEAT EXCHANGERDESIGNED FOR HIGHLY VISCOUS FLUIDS

Scraped Surface Heat Exchangers (SSHEs) are widely used in the process industry especially when highly viscous fluids have to be treated. In these heat exchangers the fluid to be heated/cooled flows axially in an annular section between a stationary outer cylinder and a powered coaxial rotor. The inner wall of the outer cylinder is scraped periodically by blades attached to the rotor. The augmentation of the heat transfer coefficient is due both to the disruption of boundary layer and to the radial mixing of the fluid. Although SSHE are frequently used in several industrial applications, the investigations available in literature about this argument are rare, especially when the laminar flow regime is encountered. Moreover, due to the specificity of each product, it is difficult to generalize the few data available, by making the thermal design of these apparatuses a critical point. The present numerical investigation is aimed to study the heat transfer performance of a concentric SSHE, especially planned for highly viscous fluid foods. A two dimensional model of the heat exchanger is considered and the PDEs governing both momentum and energy transfer in the system are integrated numerically by adopting the finite element method within Comsol Multiphysics® environment. The objective is to investigate the effect of the rotational speed of the blades on the heat transfer performance of the apparatus. The comparison of the numerical results to experimental data available in literature enables to discuss the appropriateness of the two-dimensional approach in describing the behaviour of SSHEs

Il fontanile Ariolo

Il Fontanile Ariolo, situato a sud \u2013est di Reggio Emilia, localit\ue0 Gavasseto, \ue8 inserito in un Sito di Importanza Comunitaria (SIC) della Regione Emilia Romagna, denominato "Rio Rodano e Fontanili di Fogliano e Ariolo". Il Fontanile consiste in un affioramento di limpida acqua di falda, con temperatura poco variabile nel corso dell\u2019anno; queste condizioni danno vita ad un micro-habitat nel quale trovano rifugio specie vegetali e animali peculiari. La monografia descrive gli interventi che sono stati effettuati a partire dal 2011 nell'area circostante il fontanile, nell'ambito di un progetto di riqualificazione e valorizzazione di una delle ultime zone umide planiziali a sud della Via Emilia (Piano di Azione Ambientale per il futuro sostenibile 2008/2010 - Regione Emilia Romagna). Il Fontanile \ue8 stato indagato anche dal punto di vista storico, attraverso la ricerca e lo studio di documenti di archivio, Memoriali e Cabrei. Sono infine riportati i risultati di indagini floristiche condotte nell'arco di quattro anni consecutivi, utili a fornire informazioni sulla biodiversit\ue0 vegetale del territorio

IoT-Enabled Smart Sustainable Cities: Challenges and Approaches

The ongoing diffusion of Internet of Things (IoT) technologies is opening new possibilities, and one of the most remarkable applications is associated with the smart city paradigm, which is continuously evolving. In general, it can be defined as the integration of IoT and Information Communication Technologies (ICT) into city management, with the aim of addressing the exponential growth of urbanization and population, thus significantly increasing people’s quality of life. The smart city paradigm is also strictly connected to sustainability aspects, taking into account, for example, the reduction of environmental impact of urban activities, the optimized management of energy resources, and the design of innovative services and solution for citizens. Abiding by this new paradigm, several cities started a process of strong innovation in different fields (such as mobility and transportation, industry, health, tourism, and education), thanks to significant investments provided by stakeholders and the European Commission (EC). In this paper, we analyze key aspects of an IoT infrastructure for smart cities, outlining the innovations implemented in the city of Parma (Emilia Romagna region, Italy) as a successful example. Special attention is dedicated to the theme of smart urban mobility

Inflammatory mediators and other biomarkers in co-intoxicated patients after hyperbaric oxygen therapy (HBO2)

Objective: The present study was conducted in attempt to identify reliable biomarkers in predicting the severity of neurological injury. Materials and methods: A number of 30 patients with confirmed CO poisoning and a number of 7 healthy control volunteers were involved into the study. All participants received at least 60 minutes of hyperbaric oxygen therapy (HBO2) at 2.5 atmospheres absolute (ATA). Standard blood gas analysis was performed on 10 mL venous blood samples obtained immediately before and after HBO2. Seven biomarkers and carboxyhemoglobin (COHb) levels were measured. Results: Following HBO2, all patients recovered fully and were discharged in stable condition. Significant differences between pre and post HBO2 values were found in three of the seven biomarkers analyzed: TNF-alpha, IL-10, and S100B. Additionally, S100B and NSE levels were significantly different from controls for the 10 patients who experienced temporary loss of consciousness (LOC), and IL-6 levels were significantly different from controls for all CO-intoxicated patients. Conclusion: Conclusive evidence of a correlation between a single biomarker and LOC patients was not found. However, the data suggests that the significance of the fall between pre and post HBO2 values for TNF-alpha and IL-10, along with the resolution of IL-6 levels, may herald the severity of the patient's neurological condition