• Energy Research
• engineering and technology close
• English close
• Aurora Universities Network close

Despite its unphysical tip singularity and the violation of the angular momentum balance, the classical uniformly-loaded propeller without wake rotation still represents the benchmark model both for theoretical and practical applications. The model originates from the so-called Axial Momentum Theory which is further simplified removing the radial variability of the load. However, as well-known, some mathematical simplifications are customarily introduced in this theory when the axial momentum equation is applied in a differential form. Yet, the available literature generally seems to disregard their impact on the accuracy of the predicted flow. In this paper, the errors introduced by these simplifying assumptions are evaluated by comparing the results of the aforementioned theory with those of an actuator disk approach which models the propeller wake through a force-free ring-vortex sheet. The comparison shows that significant local errors arise in the tip region, especially for highly loaded rotors.

The aim of the study is to evaluate the possibility of two step harvesting system for giant reed. The biomass was shredded and dried in the field, in second time was baled and storage. First step was cutting and shredding with a specific shredder for biomass crops rear mounted in agricultural tractor and in the second time the Arundo biomass was harvested after more day of drying in the field with continuous monitoring of the biomass moisture content. This harvesting system presents some advantages such as: the possibility of long storage of biomass (moisture content lover 14-15%), baled with a farm mechanization for hay making, possibilities of diversified use of the dried biomass (combustion and II generation ethanol). The test showed technical and energy aspect of the harvest technology but there is necessary one specific machine for shredder while the other are normally presents in the farm. The machine adopted for shredder, designed and developed by Italian constructor for more biomass herbaceous crops (Arundo, Sorghum, Panicum, Mischantus, etc..) is indicated for high vegetative developed crop and can spread the product in all soil surface or windrowing. The tests were conducted in the South of Italy (Campania region) in an experimental farm of Torrelama. The tests have showed a good performance slightly lower than 1.5 ha h-1 (1.47) with operative speed of 4.88 km h-1. The hourly production is 58.35 t ha-1 with a biomass moisture content of 42.51%. After field drying the biomass are baled and storage. Proceedings of the 26th European Biomass Conference and Exhibition, 14-17 May 2018, Copenhagen, Denmark, pp. 305-308

Fast growing trees planted as Short Rotation Coppice (SRC) are an important source of lignocellulosic biomass, due to their high yields, good combustion quality, ecological and social benefits and relatively low production costs. The quality and the price of the biomass are determined by its particle size distribution, heating value, moisture and ash content. These parameters can vary significantly as a function of the wood species and the time between the cutting phase and the chipping phase.In 2015, the Department of Agriculture of the University of Naples Federico II and the Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria (Crea), carried out some tests to identify the characteristics of the chips in eight different species grown as SRC, chipped after two months of storage: Fraxinus angustifolia, Robinia pseudoacacia, Salix alba, Populus nigra (Limatola) and four genotypes of Populus x euroamericana (Grimminge, Vesten, Hoogvorst, Muur). The average moisture content of the species was 29.30%, with an average heating value and ash content of 21.77 MJ kg-1 and 2.02%, respectively. These values differ among the various species and genotypes considered. The particle size distribution analysis revealed, instead, that independently from the species, the most represented class size was 45 to 3 mm. The variability observed in terms of dried biomass quality suggest the possibility to identify the species more suitable for the biomass combustion analyzing the mainly quality parameters, choosing the best species or different species mix wood chips to offer a better product in the commercial biomass marketing. Proceedings of the 26th European Biomass Conference and Exhibition, 14-17 May 2018, Copenhagen, Denmark, pp. 342-345

Thales was born into a noble family of Phoenician origin at the time of the 25th Olympiad (floruit 585 bc; he was 40 in the year of the solar eclipse. He had no teachers but had occasion to learn from Egyptian priests. He developed into a scholar and politician very much appreciated by Heraclitus, Herodotus and Democritus, and was always considered a man of practical wisdom. He was probably the first to speak about the immortality of the soul. He is listed as the first of many unmarried men who paved the road for philosophy. For Diogenes Laertius (Lives and Opinions of Eminent Philosophers), he was the instructor of Anaximander. Thales, the man who first discovered how to draw a right-angle triangle in a circle, was the first philosopher of nature (physis). "Philosophy begins with Thales," pointed out Bertrand Russell in 1961. This honor had been conceded also by Aristotle: "Anaximander, Thales' pupil, founded the Ionian tradition of philosophy." Many explanations may be given for the importance of water, including its importance for living processes, the economic role of the Nile, the importance of the port for Miletus and the fact that Ocean and Thetys were in Homer's tradition progenitors of the world.

The problem of transient behavior of perturbations in the linear stability analysis of vortex columns with axial flow is considered. We use the Batchelor vortex as the base flow and the analysis is carried out by focusing on a region of the parameters space in which both weak viscous exponential instabilities and transient growths of perturbations are present. The competition between the two linear effects is analyzed in a certain range of axial and azimuthal wavenumbers. The numerical discretization has been performed by employing an accurate Chebyshev collocation spectral method. The computations of the growth function evolution and of the optimal perturbations have been conducted by implementing two different strategies, the matrix exponentiation and the direct-adjoint techniques, and a comparison in terms of computational cost and accuracy is presented. Furthermore, some aspects of the competition between viscous instabilities and transient effects, in a swirl numbers range in which are both present, are discussed

This brief commentary is focused on the experimental procedures employed in the evaluation of both cognitive and balance impairments of aging patients. This is an important ergonomic issue that might be used for research purposes. In fact, the corrected assessment of impairments during aging may favor the development of new integrated ergonomic strategies to ameliorate ADL together with the reduction of environmental risks.

The paper refers to the final phase of the Smart Case research project “Innovative solutions for the optimization of multi-functional primary energy consumption and indoor living conditions in the Building System”. The aim of the research was to develop tools and methodologies to support and orient the design of new buildings in the Mediterranean area, with regard to the selection of envelope technologies for the best overall energetic and environmental performance of the building system. Further research developments on the topic may concern actions aimed at moving from the Nearly Zero Energy to the Plus Energy model. The interaction between the building and the smart grid will be one of the main aspects to be investigated with a systemic perspective towards smart cities. TECHNE - Journal of Technology for Architecture and Environment, TECHNE: Special Series Vol. 1

ECOS2010 - 23rd International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, June 14-17 2010, Lausanne, Switzerland Ecoefficiency and renewable energy for a sustainable world + Developments, application and teaching of methods in: - Basic and applied thermodynamics - Thermoeconomics and environomics - Simulation, improvement and optimization of energy conversion systems - Process design, analysis and integration of thermal and chemical systems - Diagnostic and control of thermal systems - Environmental impact and sustainability of energy systems + Relevant physical systems - Conventional and advanced power plants - Polygeneration and District heating/cooling systems - New technologies in heat pumps, refrigeration and air conditioning - New technologies for electricity (co)generation - Industrial process plants - Energy storage - Carbon Capture and Storage - Hydrogen and natural gas technologies - Biomass conversion systems - Energy conversion systems for transportation - Water Desalination and Treatment + Focus points - Technology, environmental and economical aspects of biofuels and other renewable energies (biomass, geothermal, thermal solar) - Fuel cells systems - Heat pumps and Organic Rankine Cycles