A study on the fluid dynamics of domestic Gas burners

Domestic gas burners are investigated experimentally and numerically in order to further understand the fluid dynamics processes that drive the cooking appliance performances. In particular, a numerical simulation tool has been developed in order to predict the onset of two flame instabilities which may deteriorate the performances of the burner: the flame back and flame lift. The numerical model has been firstly validated by comparing the simulated flow field with a data set of experimental measurements. A prediction criterion for the flame back instability has been formulated based on isothermal simulations without involving the combustion modelization. This analysis has been verified by a Design Of Experiments investigation performed on different burner prototype geometries. On the contrary, the formulation of a prediction criterion regarding the flame lift instability has required the use of a combustion model in the numerical code. In this analysis, the structure and aerodynamics of the flame generated by a cooking appliance has thus been characterized by experimental and numerical investigations, in which, by varying the flow inlet conditions, the flame behaviour was studied from a stable reference case toward a complete blow-out.

Violenze in famiglia e molestie sul lavoro: aspetti socio-criminologici e giuridici nell'ordinamento italiano e francese.

L'elaborato si pone l'obiettivo di indagare il complesso quadro delle molestie in famiglia e sul lavoro nell'ordinamento italiano e di effettuare una comparazione con un ordinamento appartenente alla stessa tradizione giuridica, l'ordinamento francese. Nel corso dell'esposizione saranno ricostruiti gli aspetti socio-criminologici e giuridici delle molestie in famiglia verso i soggetti deboli, donne, minori, anziani o portatori di handicap, le molestie sul luogo di lavoro quali molestie sessuali e mobbing, le molestie a distanza o stalking, che per molti aspetti rappresentano un fenomeno sommerso e poco conosciuto. La tesi intende analizzare soprattutto le forme di molestie psicologiche e meno conosciute. La ricostruzione teorico-normativa degli argomenti trattati è integrata con i risultati di una ricerca quantitativa e qualitativa tratta dalla giurisprudenza dei due paesi. Il lavoro, quindi, è organizzato in due parti: la prima è incentrata sugli aspetti teorici, socio-criminologici e giuridici e la seconda è dedicata alla ricerca empirica, che è stata condotta utilizzando quali fonti di dati le sentenze della Suprema Corte di Cassazione italiana e francese.

Essays on the Empirical Analysis of Economic and Political Development in Sub-Saharan Africa

In Sub-Saharan Africa, non-democratic events, like civil wars and coup d'etat, destroy economic development. This study investigates both domestic and spatial effects on the likelihood of civil wars and coup d'etat. To civil wars, an increase of income growth is one of common research conclusions to stop wars. This study adds a concern on ethnic fractionalization. IV-2SLS is applied to overcome causality problem. The findings document that income growth is significant to reduce number and degree of violence in high ethnic fractionalized countries, otherwise they are trade-off. Income growth reduces amount of wars, but increases its violent level, in the countries with few large ethnic groups. Promoting growth should consider ethnic composition. This study also investigates the clustering and contagion of civil wars using spatial panel data models. Onset, incidence and end of civil conflicts spread across the network of neighboring countries while peace, the end of conflicts, diffuse only with the nearest neighbor. There is an evidence of indirect links from neighboring income growth, without too much inequality, to reduce the likelihood of civil wars. To coup d'etat, this study revisits its diffusion for both all types of coups and only successful ones. The results find an existence of both domestic and spatial determinants in different periods. Domestic income growth plays major role to reduce the likelihood of coup before cold war ends, while spatial effects do negative afterward. Results on probability to succeed coup are similar. After cold war ends, international organisations seriously promote democracy with pressure against coup d'etat, and it seems to be effective. In sum, this study indicates the role of domestic ethnic fractionalization and the spread of neighboring effects to the likelihood of non-democratic events in a country. Policy implementation should concern these factors.

Second law analysis and simulation techniques for the energy optimization of buildings

The research activity described in this thesis is focused mainly on the study of finite-element techniques applied to thermo-fluid dynamic problems of plant components and on the study of dynamic simulation techniques applied to integrated building design in order to enhance the energy performance of the building. The first part of this doctorate thesis is a broad dissertation on second law analysis of thermodynamic processes with the purpose of including the issue of the energy efficiency of buildings within a wider cultural context which is usually not considered by professionals in the energy sector. In particular, the first chapter includes, a rigorous scheme for the deduction of the expressions for molar exergy and molar flow exergy of pure chemical fuels. The study shows that molar exergy and molar flow exergy coincide when the temperature and pressure of the fuel are equal to those of the environment in which the combustion reaction takes place. A simple method to determine the Gibbs free energy for non-standard values of the temperature and pressure of the environment is then clarified. For hydrogen, carbon dioxide, and several hydrocarbons, the dependence of the molar exergy on the temperature and relative humidity of the environment is reported, together with an evaluation of molar exergy and molar flow exergy when the temperature and pressure of the fuel are different from those of the environment. As an application of second law analysis, a comparison of the thermodynamic efficiency of a condensing boiler and of a heat pump is also reported. The second chapter presents a study of borehole heat exchangers, that is, a polyethylene piping network buried in the soil which allows a ground-coupled heat pump to exchange heat with the ground. After a brief overview of low-enthalpy geothermal plants, an apparatus designed and assembled by the author to carry out thermal response tests is presented. Data obtained by means of in situ thermal response tests are reported and evaluated by means of a finite-element simulation method, implemented through the software package COMSOL Multyphysics. The simulation method allows the determination of the precise value of the effective thermal properties of the ground and of the grout, which are essential for the design of borehole heat exchangers. In addition to the study of a single plant component, namely the borehole heat exchanger, in the third chapter is presented a thorough process for the plant design of a zero carbon building complex. The plant is composed of: 1) a ground-coupled heat pump system for space heating and cooling, with electricity supplied by photovoltaic solar collectors; 2) air dehumidifiers; 3) thermal solar collectors to match 70% of domestic hot water energy use, and a wood pellet boiler for the remaining domestic hot water energy use and for exceptional winter peaks. This chapter includes the design methodology adopted: 1) dynamic simulation of the building complex with the software package TRNSYS for evaluating the energy requirements of the building complex; 2) ground-coupled heat pumps modelled by means of TRNSYS; and 3) evaluation of the total length of the borehole heat exchanger by an iterative method developed by the author. An economic feasibility and an exergy analysis of the proposed plant, compared with two other plants, are reported. The exergy analysis was performed by considering the embodied energy of the components of each plant and the exergy loss during the functioning of the plants.

Conservation genetics of European wildcat (Felis silvestris silvestris): a wide and integrating analysis protocol for admixture inferences and population structure

Introgression of domestic cat genes into European wildcat (Felis silvestris silvestris) populations and reduction of wildcats’ range in Europe, leaded by habitat loss and fragmentation, are considered two of the main conservation problems for this endangered feline. This thesis addressed the questions related with the artificial hybridization and populations’ fragmentation, using a conservation genetics perspective. We combined the use of highly polymorphic loci, Bayesian statistical inferences and landscape analyses tools to investigate the origin of the geographic-genetic substructure of European wildcats (Felis silvestris silvestris) in Italy and Europe. The genetic variability of microsatellites evidenced that European wildcat populations currently distributed in Italy differentiated in, and expanded from two distinct glacial refuges during the Last Glacial Maximum. The genetic and geographic substructure detected between the eastern and western sides of the Apennine ridge, resulted by adaptation to specific ecological conditions of the Mediterranean habitats. European wildcat populations in Europe are strongly structured into 5 geographic-genetic macro clusters corresponding to: the Italian peninsular & Sicily; Balkans & north-eastern Italy; Germany eastern; central Europe; and Iberian Peninsula. Central European population might have differentiated in the extra-Mediterranean Würm ice age refuge areas (Northern Alps, Carpathians, and the Bulgarian mountain systems), while the divergence among and within the southern European populations might have resulted by the Pleistocene bio geographical framework of Europe, with three southern refugia localized in the Balkans, Italian Peninsula and Iberia Peninsula. We further combined the use of most informative autosomal SNPs with uniparental markers (mtDNA and Y-linked) for accurately detecting parental genotypes and levels of introgressive hybridization between European wild and domestic cats. A total of 11 hybrids were identified. The presence of domestic mitochondrial haplotypes shared with some wild individuals led us to hypnotize the possibility that ancient introgressive events might have occurred and that further investigation should be recommended.

Building Peace and/or Gender Equality. Changing Attitudes around Peace, Development and Security in International Cooperation in Rwanda.

The times following international or civil conflicts but also violent revolutions often come with unequal share of the peace dividend for men and women. Delusions for women who gained freedom of movement and of roles during conflict but had to step back during reconstruction and peace have been recorded in all regions of the world. The emergence of peacebuilding as a modality for the international community to ensure peace and security has slowly incorporated gender sensitivity at the level of legal and policy instruments. Focusing on Rwanda, a country that has obtained significant gender advancement in the years after the genocide while also obtaining to not relapse into conflict, this research explores to what extent the international community has contributed to this transformation. From a review of evaluations, findings are that many of the interventions did not purse gender equality, and overall the majority understood gender and designed actions is a quite superficial way which would hardly account for the significative advancement in combating gender discrimination that the Government, for its inner political will, is conducting. Then, after a critique from a feminist standpoint to the concept of human security, departing from the assumption (sustained by the Governemnt of Rwanda as well) that domestic violence is a variable influencing level of security relevant at the national level, a review of available secondary data on GBV is conducted an trends over the years analysed. The emerging trends signal a steep increase in prevalence of GBV and in domestic violence in particular. Although no conclusive interpretation can be formulated on these data, there are elements suggesting the increase might be due to augmented reporting. The research concludes outlining possible further research pathways to better understand the link in Rwanda between the changing gender norms and the GBV.