A multi-dimensional heat conduction analysis: analytical solutions versus F.E. methods in simple and complex geometries with experimental results comparison

Abstract Computer codes are widely used to predict heat transfer fields. Modeling is accomplished in multidimensional media with homogenous or not homogenous thermal conductivity, with or without volume heat sources and enthalpy flux. This paper compares the analytical solution of temperature fields in a few physical cases such as aliment cakes, capacitors, gas turbine blades, tanks with infinite element computer results and experimental results. The analytical solution of heat transfer partial differential equations presented in this paper appears in the form of the sum of effects. One of them is an infinite series in term of eigenvalues that is easily managed through mathematical commercial codes available even for palmar calculations. A comparison with experimental results shows that the concept of analytical solution has application in many physical phenomena without going to the complexity of computer code modeling

Particle swarm optimization of GaAs-AlGaAS nanowire photonic crystals as two-dimensional diffraction gratings for light trapping

Semiconductor nanowire ordered arrays represent a class of bi-dimensional photonic crystals that can be engineered to obtain functional metamaterials. Here is proposed a novel approach, based on a particle swarm optimization algorithm, for using such a photonic crystal concept to design a semiconductor nanowire-based two-dimensional diffraction grating able to guarantee an in-plane coupling for light trapping. The method takes into account the experimental constraints associated to the bottom-up growth of nanowire arrays, by processing as input dataset all relevant geometrical and morphological features of the array, and returns as output the optimised set of parameters according to the desired electromagnetic functionality of the metamaterial. A case of study based on an array of tapered GaAs-AlGaAs core-shell nanowire heterostructures is discussed

"Sacra Tharrhica Project": Preliminary Results of 3D Virtual Reconstruction of the Punic-Roman Sacred Areas of Tharros, Sardinia

AbstractThe "Sacra Tharrhica Project" was started by the University of Bologna in cooperation with the University of Cagliari in 2017. The aim is to obtain a 3D virtual reconstruction of all temple structures of the Punic settlement of Tharros on the central west coast of Sardinia, starting from a systematic architectural and archaeological study of the Punic and Roman phases of the buildings. The project has firstly focused on the "Monumental Temple" or "Doric half-columns Temple". This Punic sacred area was probably monumentalized between the late 4th and 3rd centuries B.C. After the Roman conquest, it was rebuilt between the 1st century B.C. and the 1st century A.D

low enthalpy geothermal systems for air conditioning a case study in the mediterranean climate

Abstract This paper presents a preliminary evaluation of the technical and economic feasibility of a low-enthalpy geothermal system for air conditioning and its integration with other systems, including a photovoltaic plant and an electrical storage system. The pilot building is a research center located in the southern side of the Mediterranean basin (Sardinia, Italy). Preliminarily, the main geological, hydrogeological and geothermal characteristics of the area were analyzed. Then, an energetic assessment of the building and its plants was performed. The hourly production of a photovoltaic plant already designed for the building was assessed. To improve the energy efficiency and the thermal energy self-consumption, an alternative thermal generation plant was proposed to replace the existing air conditioning system: a water-water heat pump coupled with a low-enthalpy geothermal probe (vertical configuration), to be embedded into the ground or placed into an existing groundwater well. The feasibility of electric storage was evaluated by considering a system capacity of 100 kWh to temporarily store and self-consume the electricity overproduced by the photovoltaic plant. A preliminary economic assessment showed the viability of the photovoltaic system. The 100 kWh-capacity electric storage will increase the self-production percentage, but it is not economically affordable. The replacement of the current air-water heat pumps with one water-water heat pump will be economically convenient if coupled with a groundwater geothermal probe, but the solution of a vertical probe embedded into the ground is unsustainable, due to high drilling costs

Realignment Course in Mathematics: design of an online valuable experience for students

[EN] Supporting students in the transition from secondary school to university is an important action to be taken in order to increase the number of people with tertiary education degrees; it has positive consequences on the citizens’ working perspective and on the national economic growth. To this purpose, in the academic year 2014/2015 the University of Turin started the Project Orient@mente, a platform of self-paced open online courses aimed to guide students in the choice of a scientific university program.  This paper focuses on the design of the Realignment Course in Mathematics, provided by the platform and aimed at the self-paced review and integration of knowledge that students are required to acquire during secondary school. Materials are created and structured according to the User Experience Design for Learning, with the aim of providing a valuable learning experience to students. Contents are delivered through an accessible learning management system integrated with an advanced computing environment and an automatic assessment system. Data from the usage of the activities and from the results of the online tests are analyzed in order to validate the design choices and the coherent structure of the course.http://ocs.editorial.upv.es/index.php/HEAD/HEAD18Barana, A.; Bogino, A.; Fioravera, M.; Floris, F.; Marchisio, M. (2018). Realignment Course in Mathematics: design of an online valuable experience for students. Editorial Universitat Politècnica de València. 1465-1473. https://doi.org/10.4995/HEAD18.2018.8226OCS1465147

Demonstration of fluorescence enhancement: via Bloch surface waves in all-polymer multilayer structures

An all-polymer photonic structure constituted by a distributed Bragg reflector topped with an ultrathin fluorescent polymer film has been studied. A Bloch surface wave resonance has been exploited to improve pumping efficiency. A strongly polarization and angle dependent fluorescence signal is found with respect to the light pumping beam and the emitted wavelength. Matching the most favorable condition for the pump coupling and the collection geometry, the signal obtained from the structure appears to be two orders of magnitude larger than the one of the bare emitting film