Experimental and Numerical Analysis of Gas Forced Convection through Microtubes and Micro Heat Exchangers

The last decade has witnessed very fast development in microfabrication technologies. The increasing industrial applications of microfluidic systems call for more intensive and systematic knowledge on this newly emerging field. Especially for gaseous flow and heat transfer at microscale, the applicability of conventional theories developed at macro scale is not yet completely validated; this is mainly due to scarce experimental data available in literature for gas flows. The objective of this thesis is to investigate these unclear elements by analyzing forced convection for gaseous flows through microtubes and micro heat exchangers. Experimental tests have been performed with microtubes having various inner diameters, namely 750 m, 510 m and 170 m, over a wide range of Reynolds number covering the laminar region, the transitional zone and also the onset region of the turbulent regime. The results show that conventional theory is able to predict the flow friction factor when flow compressibility does not appear and the effect of fluid temperature-dependent properties is insignificant. A double-layered microchannel heat exchanger has been designed in order to study experimentally the efficiency of a gas-to-gas micro heat exchanger. This microdevice contains 133 parallel microchannels machined into polished PEEK plates for both the hot side and the cold side. The microchannels are 200 µm high, 200 µm wide and 39.8 mm long. The design of the micro device has been made in order to be able to test different materials as partition foil with flexible thickness. Experimental tests have been carried out for five different partition foils, with various mass flow rates and flow configurations. The experimental results indicate that the thermal performance of the countercurrent and cross flow micro heat exchanger can be strongly influenced by axial conduction in the partition foil separating the hot gas flow and cold gas flow.

Labour, LGBT* rights, and Europe. Discourses in Italy and Serbia

At the time of writing, all three elements that are evoked in the title – emancipation and social inclusion of sexual minorities, labour and labour activism, and the idea and substance of “Europe” – are being invested by deep, long-term, and – to varied degrees – radical processes of social transformation. The meaning of words like “equality”, “rights”, “inclusion”, and even “democracy” is as precarious and uncertain as are the lives of those European citizens who are marginalised by intersecting conditions of gender, sexuality, ethnicity, and class – in a constellation of precarities that is both unifying and fragmented (fragmenting). Conflicts are played, in hidden or explicit ways, over material processes of redistribution as well as discursive practices that revolve around these words. Against this backdrop, and roughly ten years after the European Union provided an input for institutional commitment to the protection of LGBT* workers' rights with the Council Directive 2000/78/EC, the dissertation contrasts discourses on workplace equality for LGBT* persons produced by a plurality of actors, seeking to identify values, semantics, and agendas framing and informing organisations’ views and showing how each actor has incorporated LGBT* rights into its own discourse, each time in a way that is functional to the construction and/or confirmation of its organisational identity: transnational union networks, by presenting LGBT* rights as a natural, neutral commitment within the framework of universal human rights protection; left-wing organisations, by collocating activism for LGBT* rights within a wider project of social emancipation that is for all the marginalised, yet is not neutral, but attached to specific values and opposed to specific political adversaries (the right-wing, the nationalists); business networks, by acknowledging diversity as a path to better performance and profits, thus encouraging inclusion and non-discrimination of “deserving” LGBT* workers.

Educational mismathc in Italian an European labour markets (starting from the UK)

The present doctoral thesis is structured as a collection of three essays. The first essay, “SOC(HE)-Italy: a classification for graduate occupations” presents the conceptual basis, the construction, the validation and the application to the Italian labour force of the occupational classification termed SOC(HE)-Italy. I have developed this classification under the supervision of Kate Purcell during my period as a visiting research student at the Warwick Institute for Emplyment Research. This classification links the constituent tasks and duties of a particular job to the relevant knowledge and skills imparted via Higher Education (HE). It is based onto the SOC(HE)2010, an occupational classification first proposed by Kate Purcell in 2013, but differently constructed. In the second essay “Assessing the incidence and wage effects of overeducation among Italian graduates using a new measure for educational requirements” I utilize this classification to build a valid and reliable measure for job requirements. The lack of an unbiased measure for this dimension constitutes one of the major constraints to achieve a generally accepted measurement of overeducation. Estimations of overeducation incidence and wage effects are run onto AlmaLaurea data from the survey on graduates career paths. I have written this essay and obtained these estimates benefiting of the help and guidance of Giovanni Guidetti and Giulio Pedrini. The third and last essay titled “Overeducation in the Italian labour market: clarifying the concepts and addressing the measurement error problem” addresses a number of theoretical issues concerning the concepts of educational mismatch and overeducation. Using Istat data from RCFL survey I run estimates of the ORU model for the whole Italian labour force. In my knowledge, this is the first time ever such model is estimated on such population. In addition, I adopt the new measure of overeducation based onto the SOC(HE)-Italy classification.