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Present work investigates both experimentally and numerically the benefits deriving from the use of split injections in increasing the engine power output and reducing the tendency to knock of a gasoline direct injection (GDI) engine. The here considered system is characterized by an optical access to the combustion chamber. Imaging in the UV-visible range is carried out by means of a high spatial and temporal resolution camera through an endoscopic system and a transparent window placed in the piston head. This last is modified to allow the view of the whole combustion chamber almost until the cylinder walls, to include the so-called eng-gas zones of the mixture, where undesired self-ignition may occur under some circumstances. Optical data are correlated to in-cylinder pressure oscillations on a cycle resolved basis. The numerical investigation is performed through a properly developed 3D CFD model of the engine under study, which employs a flamelet model for the combustion initiated by the spark plug, and a low-temperature self-ignition model in the zones not yet reached by the flame front. The difference in the engine behavior if powered under single or double injection strategies and their influence about knocking are discussed. Split injection reduces engine cycle-by-cycle variability with respect to the single injection case, all the others relevant parameters remaining unchanged. Benefits are also obtained as regards the resistance to knocking. This is a consequence of the different flow fields arising under the two powering modes, which obviously affect the formation of chemical intermediate species in the low temperature regimes preceding self-ignition.

Abstract The European Community is dedicating a growing effort towards the development of renewable energy resources market and in particular to bio-fuels. General public is now aware green biomass represents a local renewable resource, which is widely available on the territory and exploitable under environmentally sustainable criteria for an ecologically sound economic development. Generally, the problem is to evaluate where to concentrate the institutional action for the promotion of the renewable energy sector. The goal of this paper is to develop a methodology able to analyse the feasibility of the biomass energy chain. In particular, we have analysed two aspects: the availability of resources and the enterprise structures. While the first aspect is tied to the local situation (forest and agricultural areas), the second aspect has a general relevance for the Italian mountain context.

A control technique of multilevel converter topologies based on Direct Lyapunov Control method is presented in this paper for integration of Distributed Generation (DG) resources into the power grid. The compensation of instantaneous variations in the reference current components in ac-side and dc-voltage variations of cascaded capacitors in dc-side of the interfacing system are considered properly, which is the main contribution and novelty of this work in comparison with other control strategies. The proposed control technique provides the continuous injection of active power in fundamental frequency from DG sources to the grid. In addition, reactive power and harmonic current components of loads are provided with a fast dynamic response; thereby, achieving sinusoidal grid currents in phase with load voltages, while the required power from load side is more than the maximum capacity of interfaced converter, is possible. Simulation results confirm the effectiveness of the proposed control strategy in DG technology during dynamic and steady-state operating conditions.

fragmentation of solid fuels under severe heating conditions. The devise is a modified heated strip reactor, capable to reach 2000°C in less than 0.2s. Particles are laid on the strip and pyrolysed under inert or moderately oxidizing conditions. The char particles and their fragments, generated upon pyrolysis, can be recovered and analysed to assess the fragmentation propensity of the fuel. Some preliminary experiments have been carried out on two biomass samples in order to assess the temperature time history of particles in the experimental apparatus. In particular biomass particles of approximately 2-3 mm have been used. The temperature of the heated strip reactor in such preliminary tests was varied between 1000 and 1600°C, while the strip nominal heating rate was kept at 104°C/s and the holding time was set at the value of 10s. A near infrared fast camera (38000 frames/sec) has been used to measure the temperature of the heated strip and of the particles during the tests. A heat up model was developed and validated against experimental results. The model was then used to estimate the temperature gradients across particles of biomass and of coal as well. Results show that the strip of the reactor reaches the set temperature in less than 0.2s. When particles are laid on the strip, their bottom surface, which is in physical contact with the strip, immediately reaches the set temperature value. For 1mm coal particles the upper surface can be considered at the same temperature as well. Under the most severe conditions tested (strip temperature of 1600°C , biomass particles of 2mm thickness) the temperature difference between the bottom and the upper face is 200°C after 3s and drops to 100°C after 10 s. On the whole the experimental apparatus simulates uniform heating of the particles with reasonable approximation. In the next future the apparatus will be further upgraded to operate at pressures up to 20 bar.

Wild microalgae (prokaryotic and eukaryotic photosynthetic microorganisms) - phytoplankton - is at the base of the food chain, supporting aquatic primary production. Microalgae are an ideal platform for the large-scale production of biomass because they are fast-growing, solar-powered 'biofactories' with low nutrient requirements. The variety of high-value bioproducts comes from microalgal species due to their wide physiological and functional diversity. Over the last 60 years, microalgal biotechnology has shown a range of applications: from the traditional extensive biomass production in human and animal nutrition, soil conditioning in agriculture, technologies for waste-water treatment, products for cosmetics and pharmacy, and most recently to the possible production of a 'third' generation of biofuels.

Electric vehicles (EVs) are considered a substitute for fossil-fueled vehicles due to rising fossil fuel prices and accompanying environmental concerns, and their use is predicted to increase dramatically shortly. However, the widespread use of EVs and their large-scale integration into the energy system will present several operational and technological hurdles. In the energy industry, an innovative solution known as the EVs smart parking lot (SPL) is introduced to handle EV charging and discharging electricity and energy supply challenges. This paper investigates social equity access and mobile charging stations (MCSs) for EVs, where the owner of MCSs is the EV parking lot. Accordingly, a new self-scheduling model for SPLs is presented in this paper that incorporates scheduling of the MCSs as temporary charging infrastructures while considering social equity access and optimizes SPL energy generation and storage schedule. The main objectives of this research are to (i) develop MCSs accessibility measures and quantify the equity impacts of MCSs locations by modeling prioritized demand based on several indices; (ii) determine the optimal set-points of SPL components (i.e., combined heat and power (CHP), photovoltaic system, electrical and heat-energy storage, and MCSs) to manage electrical peak demand and to maximize the economic benefits of SPLs. Results indicate that the proposed demand prioritization function model can meet the required EV charging demands for prioritized events, and the self-scheduling model for SPLs satisfies the charging demand of the EVs in the SPL location. Also, the social equity access to the EV charging stations is satisfied by analyzing the operation of MCSs around the prioritized demand of the prioritized events and social equity access indices.

Abstract The use of phase change materials (PCMs) for thermal storage in buildings was one of the first applications studied, together with typical storage tanks. An interesting possibility in building application is the impregnation of PCMs into porous construction materials, such as plasterboard or concrete, to increase thermal mass. The thermal improvements in a building due to the inclusion of PCMs depend on the climate, design and orientation of the construction, but also to the amount and type of PCM. Therefore, these projects require a complete simulation of the thermal behaviour of the designed space in the conditions of use established a priori. In this paper a simple methodology for the energetic simulation of buildings including elements with PCMs using the program TRNSYS is presented and validated. This procedure does not aim a simulation of the real transfer processes inside the materials with PCM, but to evaluate the influence of walls/ceiling/floor with PCM in the whole energy balance of a building. The key parameter in the simulations is the equivalent heat transfer coefficient which has to be determined for each material. Experimental evaluation of the coefficient is presented. The methodology is applied in a building such as a prototype room built with concrete panels with PCM.

The current fashion design, production, and consumption system, known as ‘fast fashion’, is characterized by the manufacturing of low-quality garments in a short period of time carried out in developing countries. In parallel with the deficits in social responsibility and human rights, the prevailing ‘take-make-dispose’ system in the fashion industry is one of the main causes of environmental pollution that concerns the climate change, scarcity of natural resources and health problems for the living beings. Due to these facts, discussions on Circular Design strategies – for waste reduction, components recycling, and materials reuse – became increasingly relevant throughout the globe. This paper’s aspiration is to outline a perspective towards a Circular Fashion. The concept of the Design for Sustainability requires a holistic view throughout de-signing strategies as well as the establishment of cyclical systems for the production site. Notwithstanding, the efficient integration of social and cultural dimensions are vital for Sustainable Fashion’s triumph. This work is supported by FEDER funds through the Competitiveness Factors Operational Programme - COMPETE and by national funds through FCT – Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-007136. info:eu-repo/semantics/publishedVersion