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Technologies for direct injection of fuel in compression ignition engines are in continuous development. One of the most investigated components of this system is the injector; in particular, main attention is given to the nozzle characteristics as hole diameter, number, internal shape, and opening angle. The reduction of nozzle hole diameter seems the simplest way to increase the average fuel velocity and to promote the atomization process. On the other hand, the number of holes must increase to keep the desired mass flow rate. On this basis, a new logic has been applied for the development of the next generation of injectors. The tendency to increase the nozzle number and to reduce the diameter has led to the replacement of the nozzle with a circular plate that moves vertically. The plate motion allows to obtain an annulus area for the delivery of the fuel on 360 degrees; while the plate lift permits to vary the atomization level of the spray. The experimental activities have been performed on a single-cylinder metal engine in order to evaluate the new injector concept functionality in typical engine working conditions. Then a deeper investigation of injector the characteristics has been performed in an optical single-cylinder diesel engine via high speed digital imaging in order to catch information on its operation. The results have shown a good response of the injector fuel delivery control but penalties in terms of emissions and efficiency compared to multihole nozzles. Images of the injection process showed that the fuel assumed an asymmetric shape at the exit of the injector affecting the mixing quality and, then, the combustion efficiency.

Electric vehicle seems to go well together with the growing societal trend of becoming more self-supplying with renewable electricity produced in the household. However, aligning household electricity production and electric vehicle charging have received little attention in HCI although both areas have been pursued separately for a number of years. In this paper, we present findings from a qualitative study that explore the potential of aligning electric vehicle charging with times where renewable electricity is being produced in the household. We present an empirical qualitative study of 5 households (19 persons) that own electric vehicles and also produce their own renewable electricity. Our findings, described in five themes, reveal that aligning charging and electricity production can be a challenge and tension exist for aligning consumption such as motivation, roles, mobility patterns, and electricity producing technology. We further discuss our findings and possible directions for future HCI research in the field.

AbstractThe surface oxygen exchange on oxides with high oxygen ion mobility is modelled with a two step reaction with adsorbed mono-atomic oxygen species as intermediate. Interpretation of the Po2 dependence of the exchange rates, following from this model, indicates that these adsorbed oxygen atoms are singly charged.For the stabilized δ-Bi2O3 solid electrolyte a good agreement has been found between the isotope exchange model and the electrochemical study of the oxygen exchange using gold electrodes. For the mixed La-Sr cobaltite perovskite a change in the surface exchange reaction is observed going from room temperature to 600°C. Indications are that above 450°C the bulk exchange is rate limiting with a (Po2)−1 dependence while below this temperature it is assumed that the dissociative adsorption is rate limiting with a (Po2)1/2 dependence.

Abstract For the option of “carbon capture and storage”, an integrated assessment in the form of a life cycle analysis and a cost assessment combined with a systematic comparison with renewable energies regarding future conditions in the power plant market for the situation in Germany is done. The calculations along the whole process chain show that CCS technologies emit per kWh more than generally assumed in clean-coal concepts (total CO2 reduction by 72–90% and total greenhouse gas reduction by 65–79%) and considerable more if compared with renewable electricity. Nevertheless, CCS could lead to a significant absolute reduction of GHG-emissions within the electricity supply system. Furthermore, depending on the growth rates and the market development, renewables could develop faster and could be in the long term cheaper than CCS based plants. Especially, in Germany, CCS as a climate protection option is phasing a specific problem as a huge amount of fossil power plant has to be substituted in the next 15 years where CCS technologies might be not yet available. For a considerable contribution of CCS to climate protection, the energy structure in Germany requires the integration of capture ready plants into the current renewal programs. If CCS retrofit technologies could be applied at least from 2020, this would strongly decrease the expected CO2 emissions and would give a chance to reach the climate protection goal of minus 80% including the renewed fossil-fired power plants.

Abstract Specimens of magnetostrictive materials can transform a variation of their stress-induced size into a variation of a produced magnetic field and vice versa. These phenomena are utilized in magnetostrictive energy harvesters, vibration sensors, etc. Mathematical models of magnetostrictive materials vary from complex hysteretic models to relatively simple non-hysteretic models. In this paper, three mathematical models of Galfenol are considered, namely a non-hysteretic model, a non-hysteretic model with a feedback loop, and a model where the hysteresis is represented by the Preisach operator with a simplified Preisach density function. The parameters of these models are identified from measured magnetic and magneto-elastic curves. All the models are applicable in technical praxis. The output of the non-hysteretic model with a feedback loop best fits the measured data and, to some extent, reproduces fine features of magneto-elastic curves.

Abstract Mediterranean islands have the advantage of favourable climatic conditions to use different marine renewable energy sources. Remote sensing can provide data to determine wind energy production potential and observational activity to identify, assess and detect suitable points in large marine areas. In this paper, a new combined model has been developed to integrate wind speed assessment, mapping and forecasting using Sentinel 1 satellite data through images processing and Adaptive Neuro-Fuzzy Inference System and the Bat algorithm. Synthetic Aperture Radar (SAR) satellite images from the Sentinel 1 satellite have been used in order to detect offshore and nearshore wind potential. Particularly, Sentinel 1 images have been analysed by means of the SNAP software. Then, to extract data about wind speed and direction, a GIS software for mapping the wind climate has been used. This new methodology has been applied to the North-Central coasts of Sardinia Island and then focused on six main small islands of La Maddalena archipelago. Furthermore, ten Hot Spots (HSs) have been identified as interesting because of their high-energy potential and the possibility to be considered as sites for future implementation of Wind Turbine Generators (WTGs). Finally, the ten identified HS have been used as input data to train and test the proposed forecast model.

L’articolo affronta gli aspetti generali della riqualificazione energetica degli edifici esistenti, mettendo in luce come le politiche di incentivazione e la strutturazione di alcuni percorsi tecnologici abbiano prodotto un circolo vizioso del retrofit, che agisce come un freno alla diffusione delle riqualificazioni energetiche. La prima parte si focalizza sulla letteratura internazionale, isolando alcune dimensioni utili alla ricostruzione dello stato dell’arte in Italia; la seconda parte analizza le politiche nel contesto italiano, i meccanismi che ne depotenziano gli effetti e le motivazioni della assenza di interventi di riqualificazione su scala medio-grande nelle città italiane; la terza parte affronta il tema dal punto di vista dei percorsi tecnologici, mettendo in luce alcuni aspetti inerenti la difficile strutturazione del campo organizzativo del retrofit energetico e la perdurante incertezza attorno ai dispositivi di efficienza e risparmio. Nelle conclusioni vengono fornite alcune indicazioni di policy, mettendo in luce come le politiche urbane agiscano in modo più marcato sull’efficienza energetica che sul risparmio energetico, depotenziando i sistemi di incentivazione adottati su scala nazionale.