Development of Quebracho (Schinopsis balansae) Tannin-Based Thermoset Resins

One of the major challenges currently in the field of material science is finding natural alternatives to the high-performing plastics developed in the last century. Consumers trust synthetic products for their excellent properties, but they are becoming aware of their impact on the planet. One of the most attractive precursors for natural polymers is tannin extracts and in particular condensed tannins. Quebracho (Schinopsis balansae) extract is one of the few industrially available flavonoids and can be exploited as a building block for thermoset resins due to its phenol-like reactivity. The aim of this study was to systematically investigate different hardeners and evaluate the water resistance, thermal behavior, and chemical structure of the quebracho tannin-based polymers in order to understand their suitability as adhesives. It was observed that around 80% of the extract is resistant to leaching when 5% of formaldehyde or hexamine or 10% of glyoxal or furfural are added. Additionally, furfuryl alcohol guarantees high leaching resistance, but only at higher proportions (20%). The quebracho-based formulations showed specific thermal behavior during hardening and higher degradation resistance than the extract. Finally, these polymers undergo similar chemistry to those of mimosa, with exclusive reactivity of the A-ring of the flavonoid

Design And Testing Of a Microchannel Heat Exchanger Working As Condenser And Evaporator

In the recent years, international agreements and regulations urge for a reduction of production and utilization of Hydrofluorocarbons (HFCs), while achieving high efficiency remains a crucial aspect for refrigeration and air conditioning systems. One of the possible candidates to replace the high global warming potential (GWP) fluid currently employed in heat pump systems (R410A) is the refrigerant R32, which belongs to A2L class. In addition to adopting low-GWP refrigerants, charge minimization is a major design objective for such systems, mainly in the case of flammable refrigerants. In the case of reversible heat pumps, a reduced volume of the heat exchangers limits the refrigerant charge migration between condenser and evaporator when switching between the operation modes. The refrigerant charge minimization coupled with the use of new refrigerants can therefore be considered one of the most important objectives for new heat pump developments. The microchannel technology helps for this purpose. The present paper presents an air-to-refrigerant microchannel heat exchanger working with R32, realized in the framework of the European Project GEOTeCH. The prototype heat exchanger, working both as condenser and as evaporator, has been tested on an innovative dual source (air and ground) heat pump, which can operate in heating and cooling modes. A model of the microchannel heat exchanger has also been developed and the predicted performance have been compared with the experimental measurements. In the end, the model has been used to estimate the refrigerant charge trapped in the minichannel when it works as condenser and the results have been compared with those obtained using a traditional finned coil heat exchanger

Sequential coupled numerical simulations of an air/ground-source heat pump: Validation of the model and results of yearly simulations

Numerical simulations are important tools for the assessment of exploiting geothermal energy in heat pump applications. They can be used to evaluate the performance of the system, the long-term production scenarios and the sustainability of the geothermal reservoir. The present work introduces and describes a numerical model, in which a dedicated Matlab script has been realized to allow sequentially coupled simulations of a shallow geothermal reservoir and of a heat pump system. A mathematical model of a dual-source heat pump, working alternatively with the ground or the air as heat source/sink, has been developed in Matlab environment. The heat exchangers of the heat pump have been modelled considering the equations that govern the physical phenomena. The dynamic numerical simulator FEFLOW, based on the finite element method, has been used to simulate the behaviour of the geothermal reservoir, subjected to heat extraction/reinjection by a closed loop vertical heat exchangers field. This methodological approach is useful to evaluate the performance of the coupled system in the long term, and it is important for understanding the advantages and limits of the dual-source heat pump in assuring sustainability over time avoiding the depletion of geothermal resources. The models and their coupling have been calibrated and validated with experimental data from a shallow geothermal plant located in Tribano (Padova, IT). It consists of eight coaxial borehole heat exchangers 30 m deep, connected to a 16 kW dual-source heat pump prototype. The heat pump system provides heating and cooling to an office area. The coupled model has been used to compare the performance of the heat pump when working in air-mode only or in ground-mode only. This allowed the development of a switching control strategy between the two thermal sources. Yearly simulations with the switching strategy have shown that the seasonal performance factor of the dual-source heat pump during the heating mode can be 13.8 % higher compared to the one obtained with a conventional air source heat pump and 3.8 % higher with respect to a ground source heat pump

Sequential coupled simulation of a dual source heat pump and shallow geothermal reservoir

The numerical simulation is an important tool for the assessment of exploiting geothermal energy. It can be used in shallow geothermal applications to evaluate the different production scenarios and the sustainability of the system (geothermal reservoir and heat pump) on long term. Moreover, in shallow geothermal projects, to simulate the real behaviour of the system, the load profiles of the end user and variations of the working mode of the heat pump should be taken into account. The present work introduces and describes a coupled numerical model, in which a dedicated Matlab\uae script has been realized to allow a sequential coupled simulation of a shallow geothermal reservoir exploited with a dual source heat pump. A mathematical model of a dual source heat pump that can work with the ground or the air as source/sink has been developed in Matlab\uae environment. Each component of the heat pump has been modelled considering the equations that govern the physical phenomena. The dynamic numerical simulator FEFLOW\uae has been used to simulate the behaviour of the geothermal reservoir, subjected to heat extraction/reinjection by a closed loop vertical heat exchangers field. This methodological approach is useful to evaluate the performance of the coupled system on the long term, and it is important for understanding the advantages and limits of the dual source heat pump in assuring the sustainability over time when heat is exchanged with the ground, avoiding the depletion of geothermal resources. The mathematical models have been validated with experimental data from a geothermal plant located in Tribano (Padova, IT). This is one of the four pilot sites realized within the framework of the H2020 GEOTeCH Project. It consists of eight coaxial borehole heat exchangers 30 m deep, connected to the 16 kW dual source heat pump prototype realized by HIREF S.p.A. The geothermal heat pump system has been working, and monitored, since October 2017 and it provides heating and air conditioning to an office area. Experimental results have been used to verify the new coupled model, and although the preliminary results are encouraging, further study and work are necessary to make it robust and stable for future routine work

Clinical comparison between conventional and microdissection testicular sperm extraction for non-obstructive azoospermia: Understanding which treatment works for which patient

Objectives: The superiority of microdissection testicular sperm extraction (mTESE) over conventional TESE (cTESE) for men with non-obstructive azoospermia (NOA) is debated. We aimed to compare the sperm retrieval rate (SRR) of mTESE to cTESE and to identify candidates who would most benefit from mTESE in a cohort of Caucasian-European men with primary couple’s infertility. Material and methods: Data from 49 mTESE and 96 cTESE patients were analysed. We collected demographic and clinical data, serum levels of LH, FSH and total testosterone. Patients with abnormal karyotyping were excluded from analysis. Age was categorized according to the median value of 35 years. FSH values were dichotomized according to multiples of the normal range (N) (N and 1.5 N: 1-18 mIU/mL, and > 18 mIU/mL). Testicular histology was recorded for each patient. Descriptive statistics and logistic regression analyses tested the impact of potential predictors on positive SRR in both groups. Results: No differences were found between groups in terms of clinical and hormonal parameters with the exception of FSH values that were higher in mTESE patients (p = 0.004). SRR were comparable between mTESE and cTESE (49.0% vs. 41.7%, p = 0.40). SRRs were significantly higher after mTESE in patients with Sertoli cell-only syndrome (SCOS) (p = 0.038), in those older than 35 years (p = 0.03) and with FSH >1.5N (p 1.5N (p = 0.018). Moreover, increased FSH levels (p = 0.03) and both SCOS (p = 0.01) and MA histology (p = 0.04) were independent predictors of SRR failure. Conclusions: Microdissection and cTESE showed comparable success rates in our cohort of patients with NOA. mTESE seems beneficial for patients older than 35 years, with high FSH values, or when SCOS can be predicted. Given the high costs associated with the mTESE approach, the identification of candidates most likely to benefit from this procedure is a major clinical need

Patients' perceptions of quality of care delivery by urology residents: A nationwide study

Objective To present the results of a nationwide survey among urological patients to evaluate their perception of the quality of care provided by residents. Methods An anonymous survey was distributed to patients who were referred to 22 Italian academic institutions. The survey aimed to investigate the professional figure of the urology resident as perceived by the patient. Results A total of 2587 patients were enrolled in this study. In all, 51.6% of patients were able to correctly identify a urology resident; however, almost 40% of respondents discriminated residents from fully trained urologists based exclusively on their young age. Overall, 98.2% patients rated the service provided by the resident as at least sufficient. Urology trainees were considered by more than 50% of the patients interviewed to have good communication skills, expertise and willingness. Overall, patients showed an excellent willingness to be managed by urology residents. The percentage of patients not available for this purpose showed an increasing trend that directly correlated with the difficulty of the procedure. Approximately 5-10% of patients were not willing to be managed by residents for simple procedures such as clinical visits, cystoscopy or sonography, and up to a third of patients were not prepared to undergo any surgical procedure performed by residents during steps in major surgery, even if the residents were adequately tutored. Conclusions Our data showed that patients have a good willingness to be managed by residents during their training, especially for medium- to low-difficulty procedures. Furthermore, the majority of patients interviewed rated the residents' care delivery as sufficient. Urology trainees were considered to have good communication skills, expertise and willingness

Il mercato antiquariale nella Venezia di Ruskin. L'arte medievale in Germania

I primi viaggi di Ruskin a Venezia cadono durante la dominazione austriaca, una lunga fase che vede una dispersione di materiali medievali veneziani che sono divenuti oggetto d’interesse per un mercato che risponde a sollecitazioni diverse: privati collezionisti, amatori e turisti stranieri che cercano “souvenir” ma anche committenze elevate finalizzate alla costituzione di musei e luoghi evocativi. È questo il caso dell’imponente acquisto negli anni Quaranta ( committente Federico Guglielmo di Prussia) di sculture antiche e medievali in Italia che andranno a costituire un importante nucleo per il museo di arte medievale e bizantina dei musei di stato in corso di costruzione. Tra queste si trova un gruppo interessante di opere veneziane acquistate tutte presso un unico commerciante veneziano (Pajaro). Anche il fratello di Federico Gugliemo, Carlo, acquista arte veneziana per ricreare nel castello di Glienicke un chiostro veneziano. Ancora: la Friedenkirche a Potsdam viene ornata da un mosaico acquistato a Murano dalla demolita chiesa di san Cipriano. Frammenti e opere intere vanno quindi a costituire raccolte destinate al pubblico e alla sua educazione, oppure a impreziosire edifici neomedievali o evocativi. Una spoliazione che va in direzione opposta all’attenzione di Ruskin. L’occhio e la mano di Ruskin ci hanno consegnato documentazione grafica e visiva di un patrimonio in contesto. I suoi scritti sono animati dalla attenzione ad ogni frammento, come testimonianza di un fare che è anche storia. Delle esportazioni delle opere medievali resta traccia anche nella reazione di veneziani (Seguso in primis) e si può cogliere non solo negli scritti ma nelle azioni successive la crescita di una attenzione e una sensibilità per un patrimonio che verrà sentito come identitario. Dopo l’annessione all’Italia pur non cessando l’azione del mercato e le vendite possiamo riscontrare una dinamica non solo di attenzione e forte impegno nel restauro di monumenti significativi, ma anche la costituzione di musei dove trovano posto i frammenti emersi da restauri e le sculture decontestualizzate in nome di un nuovo spirito e di una attenzione di cui Ruskin è stato attivo promotore e protagonista

Lower incidence rates but thicker melanomas in Eastern Europe before 1992: A comparison with Western Europe

The objective of this study was to investigate the epidemiology of melanoma across Europe with regard to Breslow thickness and body-site distribution. Incidence data from Cancer Incidence in 5 Continents and the EUROCARE-melanoma database were used: 28 117 melanoma cases from 20 cancer registries in 12 European countries, diagnosed between 1978 and 1992. Regression analysis and general linear modelling were used to analyse the data. Melanomas in Eastern Europe were on average 1.4 mm thicker (P<0.05) than in Western Europe and appeared more often on the trunk. From 1978 to 1992, their Breslow thickness had decreased in Western but not Eastern Europe. There was a latitude gradient in incidence, with highest rates in southern regions in Eastern Europe and an inverse gradient in Western Europe, with highest rates in the North. Mortality:incidence ratios were less favourable in southern parts across Europe, especially in Eastern Europe. If Eastern European populations copy the sunbathing behaviour of the West it is likely that in the near future a higher melanoma incidence can be expected there

IXPE instrument integration, testing and verification

The Imaging X-ray Polarimetry Explorer (IXPE) is a scientific observatory with the purpose of expand observation space adding polarization property to the X-ray source's currently measured characteristics. The mission selected in the context of NASA Small Explorer (SMEX) is a collaboration between NASA and ASI that will provide to observatory the instrumentation of focal plane. IXPE instrument is composed by three photoelectric polarimeters based on the Gas Pixel Detector (GPD) design, integrated by INFN inside the detector unit (DU) that comprises of the electrical interfaces required to control and communicate with the GPD. The three DUs are interfaced with spacecraft through a detector service unit (DSU) that collect scientific and ancillary data and provides a basically data handling and interfaces to manage the three DUs. AIV has been planned to combine calibration of DUs and Instrument integration and verification activities. Due the tight schedule and the scientific and functional requirements to be verified, in IAPS/INAF have been assembled two equipment's that work in parallel. The flight model of each DU after the environmental tests campaign was calibrated on-ground using the Instrument Calibration Equipment (ICE) and subsequently integrated in the instrument in the AIV-T process on a AIV and Calibration Equipment (ACE), both the facilities managed by Electrical Ground Support Equipment (EGSE) that emulate the spacecraft interfaces of power supply, functional and thermal control and scientific data collection. AIV activities test functionalities and nominal/off-nominal orbits activities of IXPE instrument each time a calibrated DU is connected to DSU flight model completing step by step the full instrument. Here we describe the details of instrumentation and procedures adopted to make possible the full integration and test activities compatibly with calibration of IXPE Instrument