Monthly and seasonal assessment of wind energy characteristics at four monitored locations in Liguria region (Italy)

The aim of this paper is to investigate the monthly and seasonal variation of the wind characteristics in term of wind energy potential using the wind speed data collected between 2002 and 2008 for four meteorological stations in Liguria region, in Northwest of Italy, namely Capo Vado, Casoni, Fontana Fresca and Monte Settepani. The results show that Capo Vado is the best site with a monthly mean wind speed between 2.80 and 9.98 m/s at a height of 10 m and a monthly wind power density between 90.71 and 1177.97 W/m², while the highest energy produced may be reached in December with a value of 3800 MWh. This study may provide information for developing wind energy sites and planning economical wind turbines capacity for the electricity production in Liguria region, as well as an example of how, deepening the analysis at monthly and seasonal scale, the characteristics of the sites might fall in quite different classes of power density.     

The vulnerability of wind power to climate change in Brazil

The availability and reliability of wind power depend a great deal on current and future climate conditions, which may vary in light of possible global climate change (GCC). Long-term energy planning, however, does not normally take possible future GCC into consideration, which may turn out to be a risky exercise. In the case of Brazil, the untapped wind power potential is known to be impressive, provided that climate conditions remain the same over time. The focus of this study is to analyze some possible impacts of GCC on the wind power potential of Brazil, by simulating wind conditions associated with the IPCC A2 and B2 Scenarios. Results based on the HadCM3 general circulation model and the analysis of the country's wind database indicate that the wind power potential in Brazil would not be jeopardized in the future due to possible new climate conditions. On the contrary, improved wind conditions are expected, particularly in the Northeast coast of the country. Therefore, investments in wind power generation can be an interesting way to expand renewable energy production in Brazil. However, given the large uncertainties associated with GCC models and scenarios, the findings of this paper should be viewed as a possibility rather than as a projection.     

Population dynamics of yeasts inhabiting bioethanol production with cell recycling

Seeking to understand the dynamics of the yeast population in a bioethanol fermentation process that uses cell recycling, the yeast inhabiting the fermentation tanks throughout the production season were monitored. A total of 26 yeasts were isolated from tanks in a Brazilian bioethanol distillery plant during six different periods of the season. These yeasts were evaluated with regard to fermentative capacity and all yeasts were qualified to be used for bioethanol production. Based on the numerical taxonomy, it was possible to say that they were all representative of Saccharomyces sensu stricto. A total of 10 different banding patterns were obtained from the 16 strains isolated. This work has shown that the yeast introduced at the beginning of the season was quickly replaced by one or more native yeast strains. It was also shown that the replacement of these strains is not always harmful to the process and isolating such yeasts found in the fermentation tanks could be an interesting strategy for new strain selection. Copyright © 2015 The Institute of Brewing & Distilling     

Energy from solar balloons

Solar balloons are hot air balloons in which the air is heated directly by the sun, by means of a black absorber. The lift force of a tethered solar balloon can be used to produce energy by activating a generator during the ascending motion of the balloon. The hot air is then discharged when the balloon reaches a predefined maximum height. A preliminary study is presented, along with an efficiency estimation and some considerations on possible realistic configurations.     

Physicochemical, technological properties, and health-benefits of Cucurbita moschata Duchense vs. Cehualca: A Review

Squash (Cucurbita moschata D.), is a vegetable crop native from México. Since ancient times it has been essential in the diet of rural communities and some urban areas worldwide, mainly in the nowadays squash is a marginalized crop in terms of cultivation, marketing, industrialization and research. There are few of scientific studies on its physical, chemical, physicochemical, nutrimental, functional and technological characteristics. Some scientific literature on squash highlights its importance as a source of α and β-carotene, lutein, vitamin C, dietary fiber, minerals, and phenolic compounds. These nutrimental and bioctive components are very important in providing human health benefits. Different researchers agree in indicating that more scientific studies are needed to achieve greater and better utilization of this important crop. This review will focus on the physical, chemical, nutritional, and technological aspects of the squash (C. moschata).     

Economic impacts of power electronics on electricity distribution systems

To achieve more efficient energy use, power electronics (PEs) may be employed. However, these introduce nonlinear loads (NLLs) into the system by generating undesired frequencies that are harmonic in relation to (multiples of) the fundamental frequency (60 Hz in Brazil). Consequently, devices using PEs are more efficient but also contribute significantly to degradation of power quality. Besides this, both the conventional rules on design and operation of power systems and the usual premises followed in energy efficiency programs (without mentioning the electricity consumed by the devices themselves) consider the sinusoidal voltage and current waveforms at the fixed fundamental frequency of the power grid. Thus, analysis of electricity consumption reductions in energy efficiency programs that include the use of PEs considers the reduction of kWh to the final consumer but not the additional losses caused by the increase in harmonic distortion. This article contributes to a better understanding of this problem by reporting the results of a case study of the ownership and use of television sets (TV sets) to estimate the economic impacts of residential PEs on a mainly residential electricity distribution system.     

Sustainability of a wind power plant: Application to different Moroccan sites

In this paper, three main steps allowing the definition of the sustainability of a wind power plant (WPP) are described in detail. The first step is to choose a site with a good wind potential. In this respect, two approaches have been introduced: traditional wind statistical estimations based on the identification of the Weibull probability density function on specific sites; and an innovative Kriging approach based on artificial neural networks to reconstruct the profile of the mean wind speed of the territory. In the second step, given technical details, the energetic sustainability of a WPP installation is assessed according to a model computing the wind energy production per year, as well as the details of its efficiency. Finally, as third step, a cost/benefit evaluation on the overall reduction in CO₂ emissions with respect to traditional fossil fuel energy plants is reported. From a wind speed characterisation viewpoint, the case study is referred to the overall Moroccan territory. From a WPP model viewpoint, the case study is referred to the installation of a specific WPP, which would allow the production of more than 2 GWh per year in the south Atlantic coast and of nearly 1 GWh per year in the Mediterranean coast in the neighbourhood of Tangier.     

Computer aided applications to injection molding: Transfinite/finite element thermal/stress response formulations

The paper describes two different computational approaches for simulating the effects due to temperature variations and therein the associated thermally induced stresses and warpage with emphasis on computer aided engineering applications to ‘plastic’ components. One approach is the conventional finite element approach, and the other is termed as the transfinite element approach. The development of unified thermal/stress formulations for each of the aforementioned approaches is described for applications to injection molded plastic parts. Results of both computational formulations are in excellent agreement for predicting the thermal response and unified thermal/stress response and agree qualitatively with previous studies. For this study, it is found that the transfinite element formulations are computationally more efficient although the conventional formulations can still be effectively used. Both formulations are capable of serving as powerful computational tools to help part designers to predict the thermal/stress responses accurately and effectively. The unified concepts and approaches offer potential for extension to more complex geometries and for combined heat transfer and stress problems.     

Wettability of glass substrates by molten nylon-6

A study of the adhesion of molten nylon-6 to glass, vitreous silica and dehydrated silica is performed by the sessile drop method at 243°C. The influence of polymerization conditions, nature of substrate, thermal pretreatment of the polymer and lithium chloride addition on wettability is examined. The most relevant results show that thermal pretreatment of the polymer is a determining step in wettability and that LiCl addition causes an increase of contact angle, as a consequence of the decrease in the substrate-molten polymer interactions. The results are interpreted by means of an interfacial model based on additive polar and dispersion forces.