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This work presents a new method to evaluate generation reserve margins in systems with renewable sources. In assessing the adequacy of generation reserve amounts, besides failures in generating units, their capacity intermittencies, unavailability, and capacity limits of the transmission system are duly considered. Risk indices are evaluated using quasi-sequential Monte Carlo simulation techniques. The cross-entropy method is used to treat rare events and also to identify critical equipment for operation in each scenario. The proposed method is applied to the original IEEE RTS system and to a modified configuration with insertion of wind power plants. A subsystem of the Brazilian interconnected network is also used to illustrate the practicality of the proposed method.

AbstractCellulose and lignin nanoparticles are high‐value‐added products obtained from lignocellulosic biomasses through several steps of cellulose purification and lignin extraction. These steps drastically reduce the potential feedstock revenue when carried out as stand‐alone methodologies. To increase biomass yields, we describe here a strategy to design a biorefinery focused on producing cellulose and lignin nanoparticles as main products, but also aim to recover and benefit from other biomass components using only water‐based processes. Sequential pressurized liquid extractions and diluted acid and alkaline treatments were carried out to fractionate elephant grass biomass, yielding (for every 100 g of biomass): 30 g of cellulose pulp (converted to 9 g of cellulose nanocrystals and 9 g of cellulose nanofibers); 10 g of lignin (used to produce 8.5 g of stable colloidal lignin nanoparticles by probe‐sonication in water); 7.5 g of extractives (e.g. sterols and phenolics) and 23 g of xylose (converted to 4.1 g of furfural). Alternatively, to allow for the flexible use of the cellulose fraction in the proposed biorefinery, 22 g of glucose could be produced by enzymatic hydrolysis. The results demonstrate that water‐based processes are suitable for a holistic use of biomass, providing a comprehensive set of high‐value‐added co‐products that are renewable and cost‐effective chemical, cosmetic, food, polymer and pharmaceutical solutions.

A special version of the NOAA HYSPLIT_4 model has been developed and used to estimate the atmospheric fate and transport of mercury in a North American modeling domain. Spatial and chemical interpolation procedures were used to expand the modeling results and provide estimates of the contribution of each source in a 1996 anthropogenic US/Canadian emissions inventory to atmospheric mercury deposition to the Great Lakes. While there are uncertainties in the emissions inventories and ambient data suitable for model evaluation are scarce, model results were found to be reasonably consistent with wet deposition measurements in the Great Lakes region and with independent measurement-based estimates of deposition to Lake Michigan. Sources up to 2000 km from the Great Lakes contributed significant amounts of mercury through atmospheric transport and deposition. While there were significant contributions from incineration and metallurgical sources, coal combustion was generally found to be the largest contributor to atmospheric mercury deposition to the Great Lakes.

The transportation impact on pollution and global climate change, has forced the automotive sector to search for more ecological solutions. Owing to the different properties of Fuel Cell (FC), real potential for reducing vehicles’ emissions has been witnessed. The optimization of FC integration within Electric Vehicles (EVs) is one of the original solutions. This paper presents an innovating solution of multi-stack Fuel Cell Electrical Vehicle (FCEV) in terms of efficiency, durability and ecological impact on environment. The main objective is to illustrate the interest of using the multi-stack FC system on the global autonomy, cycling, and efficiency enhancement, besides optimizing its operation performance.

We evaluate the potential of using a process-based ecosystem model (BEPS) for crop biomass mapping at 20 m resolution over the research site in Manitoba, western Canada driven by spatially explicit leaf area index (LAI) retrieved from Sentinel-2 spectral reflectance throughout the entire growing season. We find that overall, the BEPS-simulated crop gross primary production (GPP), net primary production (NPP), and LAI time-series can explain 82%, 83%, and 85%, respectively, of the variation in the above-ground biomass (AGB) for six selected annual crops, while an application of individual crop LAI explains only 50% of the variation in AGB. The linear relationships between the AGB and these three indicators (GPP, NPP and LAI time-series) are rather high for the six crops, while the slopes of the regression models vary for individual crop type, indicating the need for calibration of key photosynthetic parameters and carbon allocation coefficients. This study demonstrates that accumulated GPP and NPP derived from an ecosystem model, driven by Sentinel-2 LAI data and abiotic data, can be effectively used for crop AGB mapping; the temporal information from LAI is also effective in AGB mapping for some crop types.

Ceramic carbon electrodes were prepared via polymerization of silane materials containing sulfonic acid groups in the presence of Pt/Vulcan XC72. Cyclic voltammetry and electrochemical impedance spectroscopy were used to investigate the effects of sulfonic acid functionalities on platinum utilization and proton conductivity, as well as CCE microstructure. It has been determined that incorporation of small amounts of sulfonated silane to the CCE structure can lead to a profound enhancement of proton conductivity despite decreases in BET surface area. Retention of surface area was achieved through combination of sulfonated and unsulfonated organosilane precursors. These composite samples show improved performance during fuel cell testing than for CCEs prepared using unsulfonated precursors.

A preliminary evaluation of the performance characteristics for three types of rechargeable, ‘AA’ size, lithium cell chemistries, namely Li/TiS2 (two different manufacturers), Li/MoS2 and Li/MnO2, was carried out in order to determine their potential usefulness in the internal (implanted) battery for the electrohydraulic ventricular assist device (EVAD) being developed. The major parameters studied at 37 °C were discharge rate capability, self-discharge and cycle life. The cycle life of the lithium cells above the minimum 30 min discharge time specified for EVAD were short, with the Li/MoS2, Li/MnO2 and two Li/TiS2 cells giving 80, ∼ 11, 37 and 101 cycles, respectively, under pulsed discharge conditions. The 24 H, self-discharge study of all the cells at 37 °C showed < 1.2% decrease in capacity. Discharge rate studies showed that the Li/TiS2 cells from both manufacturers offered higher observed specific energies (85 and 133 W h/kg) and energy densities (203 and 273 W h/l), lower internal resistances (155 and 84 mΩ) and larger observed capacities (0.83 and 1.00 A h) when compared to the Li/MoS2 (49 W h/kg, 126 W h/l, 153 mΩ and 0.58 A h, respectively) and Li/MnO2 (56 W h/kg, 131 W h/l, 350 mΩ and 0.39 A h, respectively) cells operating under average EVAD load conditions. The cycle life and operating times of cells that were pulse discharged to mimic actual EVAD operating conditions were shorter than those that underwent cycling with an average EVAD load. When compared to other energy sources and the EVAD design specification, it was concluded that none of these prototype lithium cells were currently suitable for use in the EVAD due to their low cycle life.

Global climate change poses one of the greatest challenges facing humanity in this century. This article, which introduces the American Psychologist special issue on global climate change, follows from the report of the American Psychological Association Task Force on the Interface Between Psychology and Global Climate Change. In this article, we place psychological dimensions of climate change within the broader context of human dimensions of climate change by addressing (a) human causes of, consequences of, and responses (adaptation and mitigation) to climate change and (b) the links between these aspects of climate change and cognitive, affective, motivational, interpersonal, and organizational responses and processes. Characteristics of psychology that cross content domains and that make the field well suited for providing an understanding of climate change and addressing its challenges are highlighted. We also consider ethical imperatives for psychologists' involvement and provide suggestions for ways to increase psychologists' contribution to the science of climate change.