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Based on a 3-year (2011-2013) dataset of 10-min records collected at 10, 20, 40, and 80 m from the met mast of Cabauw, a time-varying investigation of the wind shear coefficient (WSC) relationship with atmospheric stability was addressed. WSC interdaily and interannual variability was analysed according to a 2-D combined representation, which confirmed a clear oval-shaped "solar shadow" caused by solar warming observed during diurnal unstable hours, and large WSCs occurring under strong stable conditions during the summer nights.Three different power law based approaches were compared to extrapolate wind resource to the turbine hub height according to the following WSC settings: (i) site's previously measured overall yearly average; (ii) site's previously measured stability-varying yearly averages; (iii) 10-min theoretically predicted values by applying the Panofsky and Dutton (PD) model. The latter proved to be the finest approach, providing extrapolated wind resource biased by 1-5% and energy yield by 5.51-10.57%, and showing the highest accuracy occurring under the most frequent (and most energetic) neutral conditions, when Weibull distribution's tail including the highest wind speed bins is particularly finely reproduced.This work confirmed how instrumental availability of detailed information on site's atmospheric stability classification is for wind energy studies.

Biodegradation rates of benzoate and related aromatic compounds, 3-nitrobenzoate, 4-chlorobenzoate, 4-chlorophenol, and 2,4-dichlorophenol by unexposed (unacclimated) and long-term exposed (acclimated) biomass were quantified using a modified fed-batch technique. The acclimated biomass was taken after approximately 1-year of operation from three lab-scale sequencing batch reactors (SBR). These reactors were operated under various cycling electron acceptor conditions with a continuous feed of a synthetic wastewater containing biogenic and nonbiogenic chemicals including benzoate, 3-nitrobenzoate, and 4-chlorophenol, but not 4-chlorobenzoate or 2,4-dichlorophenol. The unexposed biomass was taken from a full-scale wastewater treatment plant, which constituted one of the original sources of inoculum for the lab-scale SBRs. The acclimated biomass manifested high removal rates of benzoate and related aromatic compounds with additional removal of structurally similar chemicals (4-chlorobenzoate and 2,4-dichlorophenol). The unacclimated biomass showed no removal of 3-nitrobenzoate, 4-chlorobenzoate or 2,4-dichlorophenol. Addition of biogenic substrates reduced the degradation of most aromatic compounds tested, but it enhanced 2,4-dichlorophenol removal. Biodegradation rates of each aromatic compound with the biomass from the anoxic/aerobic SBR were further determined under anaerobic (absence of aeration and NO3-), anoxic (no aeration, but with surplus NO3-), standard oxygen (DO > 0.2 mg/L), and elevated oxygen (DO > 25 mg/L) conditions. The removal rate of both benzoate and 3-nitrobenzoate decreased under anaerobic condition but not under the anoxic condition; 4-chlorophenol biodegradation, on the other hand, was reduced significantly under both anoxic and anaerobic conditions. The removal rates of aromatic compounds, particularly those of 3-nitrobenzoate and 2,4-dichlorophenol, increased significantly under elevated dissolved oxygen conditions. Our results demonstrated that when the biochemical conditions shifted from oxygen-respiration to nitrate respiration, to anaerobiosis, the biodegradation rates of test aromatic compounds decreased or ceased.

Artículos en revistas Hybrid microgrids are expected to play an important role in the expansion of access to electricity in developing countries. While most of these systems are operated with dispatch strategies which do not make use of predictions about the load or about the availability of renewable energy resources, forecast-based strategies have recently gained attention as an alternative to bring down operation costs. In this work, we develop a framework to assess this potential under a range of assumptions about the quality of load and photovoltaic generation forecasts. The application of the methodology to a village of 600 households reveals cost savings ranging between 2% and 7% depending on the forecast quality and the composition of the microgrid. We also show that sizing microgrid components under the assumption of a predictive operation strategy results in a design with a higher share of intermittent generation. info:eu-repo/semantics/publishedVersion

The residential sector accounts for one-fifth of global energy consumption, resulting from the requirements to heat, cool, and light residential dwellings. It is therefore not surprising that energy efficiency in the residential market has gained importance in recent years. In this paper, we examine awareness, literacy and behavior of households with respect to their residential energy expenditures. Using a detailed survey of 1721 Dutch households, we measure the extent to which consumers are aware of their energy consumption and whether they have taken measures to reduce their energy costs. Our results show that "energy literacy" and awareness among respondents is low: just 56% of the respondents are aware of their monthly charges for energy consumption, and 40% do not appropriately evaluate investment decisions in energy efficient equipment. We document that demographics and consumer attitudes towards energy conservation, but not energy literacy and awareness, have direct effects on behavior regarding heating and cooling of the home. The impact of a moderating factor, measured by thermostat settings, ultimately results in strong variation in the energy consumption of private consumers. (C) 2013 Published by Elsevier B.V.

AbstractProjections show that biomass will remain important for reaching future EU renewable energy targets. In addition to using domestic biomass, European bioenergy markets will also partly rely on imports of biomass, in particular in trade‐oriented EU member states like the United Kingdom, the Netherlands, Belgium, and Denmark. There has been a lot of debate on the sustainability of (imported) biomass and how policy should deal with this. In this research, therefore, we defined long‐term strategies for sustainable biomass imports in European bioenergy markets. We used the input of different stakeholders in our approach through focus‐group discussions and a global survey, focusing on the following aspects: key principles of sustainable biomass trade, risks and opportunities of biomass trade, both for import regions (EU countries) and for sourcing regions, and practical barriers for trade. Overall we conclude that policies should be stable and consistent within a long‐term vision. An overall sustainability assurance framework of biomass production and use is key, but should ultimately apply to all end uses of biomass. Furthermore, the mobilization of biomass should be supported, as well as commoditization, considering the large diversity of biomass. Side impacts of biomass use should be monitored. Reducing investors’ risk perception is crucial for future developments in the biobased economy, and a clear policy to phase out fossil fuels, e.g. through a carbon tax, needs to be implemented. The results of this research are of interest for policy makers when deciding on long‐term strategies concerning sustainable bioenergy markets. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd

The Indian Ocean Experiment (INDOEX) was an international, multiplatform field campaign to measure long-range transport of air pollution from South and Southeast Asia toward the Indian Ocean during the dry monsoon season in January to March 1999. Surprisingly high pollution levels were observed over the entire northern Indian Ocean toward the Intertropical Convergence Zone at about 6°S. We show that agricultural burning and especially biofuel use enhance carbon monoxide concentrations. Fossil fuel combustion and biomass burning cause a high aerosol loading. The growing pollution in this region gives rise to extensive air quality degradation with local, regional, and global implications, including a reduction of the oxidizing power of the atmosphere.

Species distribution models (SDMs) provide realistic scenarios to explain the influence of bioclimatic variables on plant pathogen distribution. Diplodia sapinea is most harmful to plantations of both exotic and native pine species in Italy, causing economic consequences expecially to edible seed production. In this study, we developed maximum entropy models for D. sapinea in Italy to reach the following goals: (i) to carry out the pathogen's first geographical distribution analysis in Italy and determine which ecogeographical variables (EGVs) may influence its outbreaks; (ii) to detect the effect of climate change on the potential occurrence of disease outbreaks by 2050 and 2070. We used Maxent ver. 3.4.0 to develop SDMs. We used six global climate models (BCC-CSM1-1, CCSM4, GISS-E2-R, MIROC5, HadGEM2-ES and MPI-ESM-LR) for two representative concentration pathways (4.5 and 8.5) and two time projections (2050 and 2070) to detect future climate projections of D. sapinea. The most important EGVs influencing outbreaks were land cover, altitude, mean temperature of driest and wettest quarter, precipitation of wettest quarter, precipitation seasonality and minimum temperature of coldest month. The distribution of D. sapinea mostly expanded in central and southern Italy and shifted in altitude upwards on average by ca. 93m a.s.l. Moreover the fungus expanded the range where disease outbreaks may be recorded in response to an increase in the mean temperature of wettest and driest quarter by ca. 1.9 C and 5.8 C, respectively in all climate change scenarios. Precipitation of wettest quarter did not differ between current and any of future models. Under different climate change scenarios D. sapinea's disease outbreaks will be likely to affect larger areas of pine forests in the country, probably causing heavy effects on the dynamics and evolution of these stands or perhaps constraining their survival.

Roundtables for sustainable beef have evolved in national contexts as well as at the global level as a multi-stakeholder process to address sustainability concerns in the cattle sector. However, due to their relatively recent inception, the literature on the beef roundtables is extremely limited and very little scholarly work has traced their process or impact. We used semi-structured interviews with key informants to examine the governance, actions, and potential impacts of the roundtables for sustainable beef, and identified opportunities and challenges for achieving greater sustainability impact. We found that the beef roundtables are in different stages of development and implementation and that they have diverse approaches based on their geographic contexts. However, they have universally adopted a model of sector-wide continuous improvement, in contrast to roundtables for other commodities, which have in many cases adopted formal certification programs. Activities by the roundtables for sustainable beef have variously included working towards definitions of sustainable beef; setting sustainability principles and criteria; and creating working groups to address specific aspects of sustainability (e.g., verification, deforestation). Our interviews identified opportunities to expand the roundtables’ roles, activities, and sustainability impacts. This study provides a benchmark of the roundtables’ efforts to date, and generates hypotheses and ideas for how they could evolve in the future.

The hollow-fibre oxygenator is a key component of any extracorporeal circuit used to provide cardiopulmonary bypass (CPB) during open-heart surgery. Since the oxygenator is placed downstream of the pump, the energy losses over it have a direct impact on the quality of pulsatile pressure and flow waveforms. The objective of this study was to describe the effects of hydrodynamic characteristics of the oxygenator on energy transfer during pulsatile, normothermic CPB. Twenty-three adult patients scheduled for coronary bypass surgery were divided randomly into two groups, using either an oxygenator (Group 1) with a relatively high-resistance and low-compliance (2079 ± 148 dyn.s.cm-5 and 0.00348 ± 0.00071 ml.mmHg-1, respectively) or an oxygenator (Group 2) with a relatively low-resistance and high-compliance (884 ± 464 dyn.s.cm-5 and 0.01325 ± 0.00161 ml .mmHg-1, respectively). During perfusion, pre- and post-oxygenator pressures, radial artery pressure, and blood flow were recorded simultaneously. A 32% decline of mean pressure was observed in Group 1 and a 16% decline in Group 2 (p<0.0001). Another decrease by approximately 73% in mean pressure in the rest of the perfusion system was noted in both groups. The mean radial artery pressure did not differ between the groups (74 ± 6 mmHg in Group 1 and 73 ± 6 mmHg in Group 2, p=0.608). Although lower total energy transfer indices were noticed through the low-resistance oxygenator (Group 2), both oxygenators showed a decrease of the generated pump oscillatory energy of approximately 50%. Despite the differences in resistance and compliance of the hollow-fibre oxygenators used, both oxygenators cause a comparable loss of generated oscillatory energy. Exclusion of the oxygenator downstream of the pulsatile pump would improve energy transfer during CPB.