[en] Project Based Learning is a technique devoted to learning by doing. It is quite often used in technological universities since many engineering concepts are predominantly practical notions. The paper deals with a practical experience carried out at Technical University of Catalunya (UPC) in the framework of its Master of Nuclear Engineering. The goal of the project was to help students understanding some practices related to Nuclear Power Plants (NPP) engineering during the operation phase. The exercise has been strongly connected with the concept of sustainability and related to the ideas below. A NPP is designed to operate for 40 for 60 years. During such period of time, in a similar way than in other facilities, different things could happen: • Some components could become obsolete, spare parts unavailable and repairs unfeasible • New regulations could be endorsed • New techniques could offer operation advantages All these items are technological problems that could appear and need to be faced by developing engineering tasks. Project definition has to do with analysing the degraded performance of Steam Generators, its replacement and eventually converting operational problems in business opportunity by implementing a power uprating of the plant. This experience has been an interesting occasion of teaching decision making and feasibility studies.

[en] From its first edition, that took place in 2011-2012, the Masters degree in Nuclear Engineering from BarcelonaTECH has been using techniques of Project-Based Learning to fulfill the purpose of training nuclear engineers with a profile suitable for positions in the industry. The Master is sponsored by ENDESA and relies on the collaboration with institutions and companies. The Master is embedded in EMINE, the European Master in Innovation in Nuclear Energy, supported by KIC-InnoEnergy and the European Institute of Technology. (Author)

[en] Measurements of magnetic hysteresis loops performed at low temperatures on Cu-Al-Mn alloys with different Mn-content are presented. The loops are smooth and continuous above a certain temperature, while they exhibit a magnetization discontinuity below this temperature. Scaling analysis suggests that this system displays a disorder-induced phase transition line and allows determining the critical exponents (β=0.03±0.01 and βδ=13±3). Results indicate that by changing temperature, it is possible to tune the disorder responsible for the transition

[en] An acoustic emission (AE) study of the martensitic and premartensitic transitions in nearly stoichiometric Ni-Mn-Ga alloy is reported. By comparing the AE with calorimetric results, it is shown that AE is generated at both transitions. The AE intensity at the premartensitic transition is extremely weak, in accordance with its weakly first-order character. The amplitude distribution of the AE signals recorded during the martensitic transformation is a power law, with an exponent α = 2.2 ± 0.1. This value is compared with recent results obtained in other shape-memory alloys. (orig.)

[en] Using experimental data from ultrasonic and neutron scattering measurements for different Cu-based bcc alloys undergoing a martensitic transformation, we show that: (i) the relationship between the elastic constant C' and the zone boundary frequency ω_ZB of the associated phonon branch, both evaluated at the transition point T_M, conforms to the dependence predicted by a Landau model, recently proposed for martensitic transformations and (ii) the elastic anisotropy A at T_M has, within the experimental accuracy, a constant value; this last finding being not explained by the existing models. Some suggestions are envisaged to account for this fact. (orig.)

[en] We develop a simple model for the study of a first-order cubic to tetragonal structural transition in athermal conditions in systems with a certain amount of disorder. We perform numerical simulations that allow for a statistical study of the dynamics of the transition when the system is driven from the high temperature cubic phase to the low temperature degenerate tetragonal phase. Our goal is to reveal the existence of kinetic constraints that arise from the competition between the equivalent variants of the product phase and that prevent the system from reaching optimal final microstructures

[en] We have studied the kinetics of thermoelastic martensitic transformations (MT), both experimentally and using spin models. Measurements of acoustic emission and thermal pulses in Cu-Zn-Al single crystals, during thermally and stress induced MT, show that the transformation takes place as a sequence of avalanches, whose sizes and durations distribute according to power laws in more than one decade. Most features observed are qualitatively reproduced by spin models that incorporate domain interactions and frozen disorder. A systematic simulation of these models at T = 0 (no fluctuations allowed) has shown that there is a critical concentration of disorder for which avalanche sizes and durations distribute following power-laws, which appear to be independent of details of the models other than their dimensionality. We discuss the connection between the experimental results and the simulations. (orig.)

[en] The avalanche statistics in porous materials and ferroelastic domain wall systems has been studied for slowly increasing compressive uniaxial stress with stress rates between 0.2 and 17 kPa s⁻¹. Velocity peaks $v_m=\text{d}h/\text{d}t$ are calculated from the measured strain drops and used to determine the corresponding Energy distributions $N(E\equiv <!--\; ???\; -->v_m^2)$. Power law distributions $N\left(v_m^2\right)\propto <!--\; ???\; -->\left(v_m^2\right){}^{-<!--\; ???\; -->\mathrm{\epsilon <!--\; ??\; -->}}$ have been obtained over 4–6 decades. For most of the porous materials and domain wall systems an exponent $\mathrm{\epsilon <!--\; ??\; -->}=1.5\pm <!--\; ??\; -->0.1$ was obtained in good agreement with mean-field theory of the interface pinning transition. For charcoal, shale and calcareous schist we found significant deviations of the exponents from mean-field values in agreement with recent acoustic emission experiments. (paper)