1,909 research outputs found
Martin Stingelin (dir.), en collaboration avec Davide Giuriato et Sandro Zanetti, « Mir ekelt vor diesem tintenklecksenden Säkulum ». Schreibszenen im Zeitalter der Manuskripte, 2004
No full textViollet Catherine. Martin Stingelin (dir.), en collaboration avec Davide Giuriato et Sandro Zanetti, « Mir ekelt vor diesem tintenklecksenden Säkulum ». Schreibszenen im Zeitalter der Manuskripte, 2004. In: Genesis (Manuscrits-Recherche-Invention), numéro 25, 2005. pp. 159-160
Martin Stingelin (dir.), en collaboration avec Davide Giuriato et Sandro Zanetti, "Schreibkugel ist ein Ding gleich mir: von Eisen". Schreibszenen im Zeitalter der Typoskripte, 2005
No full textDitschler Susanne. Martin Stingelin (dir.), en collaboration avec Davide Giuriato et Sandro Zanetti, "Schreibkugel ist ein Ding gleich mir: von Eisen". Schreibszenen im Zeitalter der Typoskripte, 2005. In: Genesis (Manuscrits-Recherche-Invention), numéro 27, 2006. pp. 192-193
Martin Stingelin (dir.), en collaboration avec Davide Giuriato et Sandro Zanetti, « Mir ekelt vor diesem tintenklecksenden Säkulum ». Schreibszenen im Zeitalter der Manuskripte, 2004
No full textViollet Catherine. Martin Stingelin (dir.), en collaboration avec Davide Giuriato et Sandro Zanetti, « Mir ekelt vor diesem tintenklecksenden Säkulum ». Schreibszenen im Zeitalter der Manuskripte, 2004. In: Genesis (Manuscrits-Recherche-Invention), numéro 25, 2005. pp. 159-160
sj-tif-1-tab-10.1177_1759720X221124543 – Supplemental material for Comparable long-term retention rates and effects on bone mineral density of denosumab treatment in patients with osteoporosis with or without autoimmune inflammatory rheumatic diseases: real-life data
No full textSupplemental material, sj-tif-1-tab-10.1177_1759720X221124543 for Comparable long-term retention rates and effects on bone mineral density of denosumab treatment in patients with osteoporosis with or without autoimmune inflammatory rheumatic diseases: real-life data by Angelo Fassio, Davide Gatti, Davide Bertelle, Elena Fracassi, Giulia Zanetti, Ombretta Viapiana, Maurizio Rossini and Giovanni Adami in Therapeutic Advances in Musculoskeletal Disease</p
Drainage of retro-parapharyngeal abscess: An additional indication for endoscopic sinus surgery
No full textDeep neck abscesses are life-threatening conditions, in early stages preferably treated by intravenous antibiotic therapy; in advanced stages, surgical drainage is mandatory. We report two cases of retro-parapharyngeal abscess with prevalent retronasopharyngeal extension in two men aged 60 and 82, both of whom underwent transnasal endoscopic drainage. The main surgical steps were incision of the posterior pharyngeal mucosal wall, widening of the incision, drainage of purulent collection and careful dissection and removal of the necrotic tissue. The first patient, with an abscess associated with chronic otitis media and presenting hypoglossal nerve palsy, quickly recovered from pharyngodinia, otalgia and trismus. Twenty-six months after surgery, he is symptom-free, with hemitongue atrophy due to denervation as the only residual sign. The second patient, affected by skull base osteomyelitis secondary to malignant external otitis, after a first successful drainage, underwent a second endoscopic procedure for the reoccurrence of an abscess in the contralateral retroparapharyngeal space. Twelve months after the first surgery, the patient reported an improvement of symptoms, except for persistent dysphonia related to vagal nerve palsy. At follow-up MR, another abscess was detected in the left retro-parapharyngeal space. In selected cases of abscess, transnasal endoscopic drainage may be an effective alternative to external approaches. Minimal morbidity, the absence of cervical or palatal scars and a short hospitalization time can be considered as important advantages in comparison to external approaches. Patients with abscess secondary to skull base osteomyelitis require close imaging surveillance because of the difficulty of definitive control of the disease
Rheological characterisation of sludge coming from a wastewater treatment plant
No full textThe aim of this study was that of studying the rheology of sewage sludge using two different rheological test protocols taken from literature and comparing them in order to evaluate which useful information are given from every protocol. Approach: Two different protocols have been used taking particularly into account the problems connected to sludge heterogeneous composition and to the interaction between solid-solid and solid-water particles in order to completely understand the rheological behavior of this suspension; moreover, the consequences of particular effects connected to test geometry and conditions have been considered. Two fundamental parameters have been modified in the samples: The total solids content and the polyelectrolyte addition. Sludge with 3 and 5% of total solids have been investigated, with or without polyelectrolyte using also microscope analysis to understand the effect of polyelectrolyte on the sludge. Results: As expected, it was noticed that sludge viscosity grows up increasing the total solids content and with the presence of polyelectrolyte. The effect of polyelectrolyte is that of separating the liquid-phase from the solid-phase of the sludge giving a more space-heterogeneous suspension with higher viscosity and higher non-Newtonian behavior. Conclusion: This study proved that combining two different protocols of analysis can be useful to furnish important and complementary information on sludge rheology especially when some parameters change from sample to sample. Moreover, in order to have good and consistent results, it is necessary to use particular attention on samples pretreatment
CHARACTERIZATION OF CRUMB RUBBER FROM END-OF-LIFE TYRES FOR PAVING APPLICATIONS
No full textCrumb rubber (CR) derived from grinding of end-of-life tyres (ELTs) may be successfully used as a bitumen modifier or as a supplementary component in the production of bituminous mixtures employed for the construction and maintenance of road pavements. However, CRs deriving from different sources and processes yield effects on performance under traffic loading and on gaseous emissions produced during laying on site which may change considerably depending upon their physical and chemical properties. In order to quantitatively assess the possible variability of CR characteristics, samples were taken from 9 Italian and 2 foreign ELT processing plants. Investigation activities included field surveys, during which plants were examined in detail, and laboratory tests, which focused on physical and chemical characterization of CR. Based on the analysis of available technical information and experimental data, it was possible to find relationships between the peculiar characteristics of treatment cycles and corresponding CR propertie
EXPERIMENTAL AND NUMERICAL STUDY OF EVAPORATORS FOR MULTI-SOURCE HEAT PUMPS
No full textThe present thesis aims at describing the operation of innovative evaporators employed in multi-source heat pumps. The exploitation of multiple sources at the low-pressure side of a heat pump is recently considered to be a good solution to air source heat pumps, whose performance is limited to the external air temperature and to the necessity of periodic defrosting cycles.
In order to study the advantage of using multi-source heat pumps, it is necessary to investigate the performance of the selected evaporators at the desired operative conditions: to accomplish this purpose, the results of both experimental activities and simulations realized with ad hoc developed numerical tools are presented in this work.
First, a 16 kW air/ground dual-source heat pump working with R32 for heating, cooling and DHW production has been experimentally characterized. The advantage of such configuration is that it is possible to extract or dissipate heat with the most convenient thermal source and the possibility to undersize the ground loop compared to a conventional ground-coupled system. In the framework of this activity, a novel minichannels air-to-refrigerant heat exchanger has been mounted on the heat pump and used as the evaporator.
A 5 kW air/solar dual-source heat pump for water heating has also been experimentally studied in this work. When operating in solar-assisted mode, the evaporator consists of three PV-T (photovoltaic-thermal) solar collectors connected in parallel, where the refrigerant (CO2) is directly sent after the throttling process. The main advantage of using a solar evaporator is that, since the solar radiation can be considered as a forced heat flux, the evaporation temperature can be higher than that obtained in an air-to-refrigerant heat exchanger when the solar irradiance is high. Furthermore, the use of a PV-T device can reduce the global power consumption, due to PV electricity production. The presented heat pump prototype has been also designed to work in an innovative flooded-evaporation configuration: in this case, liquid CO2 enters the collectors and the flow is ensured by a natural circulation loop. The main advantage is the possibility to eliminate the maldistribution issues occurring in heat pump evaporators.
All the heat exchangers used analyzed experimentally have been numerically modelled in this work. A model of a brazed plate heat exchange, of a conventional finned coil heat exchanger, of an air-to-refrigerant minichannels heat exchanger and of a PV-T evaporator have been realized. The models have been developed in Matlab environment, following a distributed parameters approach: each discretized element is treated as an independent heat exchanger where continuity, momentum and energy equations are solved; in this sense, a “physical” approach has been used. This managed to investigate the operation of the studied heat pumps in non-tested conditions to further optimize the design and functioning of their components.
However, all the developed evaporators models are partly based on empirical correlations, in particular for the determination of the heat transfer coefficients on the refrigerant side. Empirical correlations are not always accurate and a well-established predictive model is not available in the literature. For this reason, a section of the present manuscript has been dedicated to presenting the description and the first results of a new CFD method for modelling the evaporation phenomenon in small channels during annular flow with refrigerants. The simulations have been realized in OpenFOAM environment and are based on the application of the Volume of Fluid method.The present thesis aims at describing the operation of innovative evaporators employed in multi-source heat pumps. The exploitation of multiple sources at the low-pressure side of a heat pump is recently considered to be a good solution to air source heat pumps, whose performance is limited to the external air temperature and to the necessity of periodic defrosting cycles.
In order to study the advantage of using multi-source heat pumps, it is necessary to investigate the performance of the selected evaporators at the desired operative conditions: to accomplish this purpose, the results of both experimental activities and simulations realized with ad hoc developed numerical tools are presented in this work.
First, a 16 kW air/ground dual-source heat pump working with R32 for heating, cooling and DHW production has been experimentally characterized. The advantage of such configuration is that it is possible to extract or dissipate heat with the most convenient thermal source and the possibility to undersize the ground loop compared to a conventional ground-coupled system. In the framework of this activity, a novel minichannels air-to-refrigerant heat exchanger has been mounted on the heat pump and used as the evaporator.
A 5 kW air/solar dual-source heat pump for water heating has also been experimentally studied in this work. When operating in solar-assisted mode, the evaporator consists of three PV-T (photovoltaic-thermal) solar collectors connected in parallel, where the refrigerant (CO2) is directly sent after the throttling process. The main advantage of using a solar evaporator is that, since the solar radiation can be considered as a forced heat flux, the evaporation temperature can be higher than that obtained in an air-to-refrigerant heat exchanger when the solar irradiance is high. Furthermore, the use of a PV-T device can reduce the global power consumption, due to PV electricity production. The presented heat pump prototype has been also designed to work in an innovative flooded-evaporation configuration: in this case, liquid CO2 enters the collectors and the flow is ensured by a natural circulation loop. The main advantage is the possibility to eliminate the maldistribution issues occurring in heat pump evaporators.
All the heat exchangers used analyzed experimentally have been numerically modelled in this work. A model of a brazed plate heat exchange, of a conventional finned coil heat exchanger, of an air-to-refrigerant minichannels heat exchanger and of a PV-T evaporator have been realized. The models have been developed in Matlab environment, following a distributed parameters approach: each discretized element is treated as an independent heat exchanger where continuity, momentum and energy equations are solved; in this sense, a “physical” approach has been used. This managed to investigate the operation of the studied heat pumps in non-tested conditions to further optimize the design and functioning of their components.
However, all the developed evaporators models are partly based on empirical correlations, in particular for the determination of the heat transfer coefficients on the refrigerant side. Empirical correlations are not always accurate and a well-established predictive model is not available in the literature. For this reason, a section of the present manuscript has been dedicated to presenting the description and the first results of a new CFD method for modelling the evaporation phenomenon in small channels during annular flow with refrigerants. The simulations have been realized in OpenFOAM environment and are based on the application of the Volume of Fluid method
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