Increase In Total Capacity Research Articles

Future Wind Power Scenario Synthesis Through Power Spectral Density Analysis

Scenarios of near future wind power are synthesized by considering the power spectral density (PSD), statistical characteristics, and the future capacity. The PSD of the wind power follows different power laws over different frequency ranges and is approximated by a piecewise function. A scaling exponent of the power law for a particular piece can be approximated by the slope of an affine function fitted to a logarithmic plot of the PSD. Each piece of the function has a different trend as the total capacity increases. Slope trends, the first PSD value, and the last PSD value are trained to forecast the PSD. Then, future wind power scenarios are synthesized from the forecasted PSD. In this process, phase angles are searched using a genetic algorithm while satisfying forecasted statistical characteristics for the given capacity. Our approach is simulated and validated for wind power for seven years in ERCOT and is used to synthesize a future wind power scenario at 10,000 MW capacity. Our approach could also be used to generate wind power scenarios at present capacity for many stochastic optimization problems in power systems.

Heat regeneration of hydroxyapatite/attapulgite composite beads for defluoridation of drinking water

Regeneration is one of the key factors in evaluating an adsorbent. A novel heat regeneration method for hydroxyapatite/attapulgite (HAP/ATT) composite beads was studied. The investigation included heat regeneration temperature, regeneration time, and regeneration effects. A possible mechanism for the heat regeneration is described that explains the results of XPS, and SEM with EDAX. Exhausted HAP/ATT composite beads can be regenerated for more than 10 cycles using boiling water or steam. The total capacity increases by 10 times compared to a single defluoridation cycle. The regeneration process involves F− ions adsorbed on the surface of the beads to move quickly into the bulk of the HAP through the effect of heating this composite material. The surface active sites are thus re-exposed and the beads recover their fluoride sequestration properties. HAP/ATT composite beads were successfully used for the removal of fluoride from field water taken from a nearby village where fluoride contamination is endemic. Defluoridation and regeneration cycles performed in the same container provide a high efficient and simple operation. No chemical agents are used and no waste products are produced during the heat regeneration process, so this is a nearly zero emission process. This method can easily be up-scaled to a large throughput application.

Online State-of-Health Assessment for Battery Management Systems

Battery-powered embedded systems have known a rapid evolution in recent years, as nickel-metal hydride (Ni-MH) battery technology has enabled important reductions in size and proportional increases in total capacity over the older nickel-cadmium (Ni-Cd) and lead-acid battery types. This paper addresses the problem of state-of-health (SoH) estimation and prediction for use in resource-constrained Ni-MH-battery-powered embedded systems. We propose a novel SoH prediction methodology, presenting both a theoretical analysis of the estimation algorithm and the detailed description of hardware and software implementation. Two versions of estimation algorithms are proposed, along with the analysis of their performances in terms of prediction accuracy and required processing power, as the SoH prediction is designed to run online, being part of an embedded battery management system.

A Dynamic Incentive Mechanism for Transmission Expansion in Electricity Networks: Theory, Modeling, and Application

We propose a price-cap mechanism for electricity-transmission expansion based on redefining transmission output in terms of financial transmission rights. Our mechanism applies the incentive-regulation logic of rebalancing a two-part tariff. First, we test this mechanism in a three-node network. We show that the mechanism intertemporally promotes an investment pattern that relieves congestion, increases welfare, augments the Transco’sprofits, and induces convergence of prices to marginal costs. We then apply the mechanism to a grid of northwestern Europe and show a gradual convergence toward a common-price benchmark, an increase in total capacity, and convergence toward the welfare optimum.

Self-Supported Three-Dimensional Nanoelectrodes for Microbattery Applications

A nanostructured three-dimensional (3D) microbattery has been produced and cycled in a Li-ion battery. It consists of a current collector of aluminum nanorods, a uniform layer of 17 nm TiO(2) covering the nanorods made using ALD, an electrolyte and metallic lithium counter electrode. The battery is electrochemically cycled more than 50 times. The increase in total capacity is 10 times when using a 3D architecture compared to a 2D system for the same footprint area.

The capacitive characteristics of supercapacitors consisting of activated carbon fabric–polyaniline composites in NaNO3

Abstract A sandwich-type supercapacitor consisting of two similar activated carbon fabric–polyaniline (ACF–PANI) composite electrodes was demonstrated to exhibit excellent performance (i.e., highly reversibility and good stability) in NaNO3. Polyaniline with the charge density of polymerization less than or equal to 9 C cm−2 synthesized by means of a potentiostatic method showed a high specific capacitance of 300 F g−1. Influences of the polymerization charge density (i.e., the polymer loading) on the capacitive characteristics of ACF–PANI composites were compared systematically. The capacity of an ACF–PANI electrode reach ca. 3.4 F cm−2 (a 100% increase in total capacity) when the charge density of polymerization is equal to 9 C cm−2. The surface morphology of these ACF–PANI composites was examined by a scanning electron microscope (SEM).

Digestive adjustments in cedar waxwings to high feeding rate

Birds may dramatically increase their food intake during migratory periods or during winter. We tested the hypotheses that when birds are hyperphagic, (a) their digesta retention time and extraction efficiency will not change compared with that of birds feeding at reduced rates, (b) their total capacity for breakdown and absorption of nutrients will increase, and (c) the mechanism responsible for the increase in total capacity will be an increase in amount of intestine rather than an increase in intestinal tissue-specific enzyme activity or nutrient transporter activity. We measured gut anatomy, retention time of digesta, enzyme hydrolysis rates, nutrient absorption rates, and digestive efficiency in individual cedar waxwings (Bombycilla cedrorum) acclimated to –20°C or +21°C. Compared with cedar waxwings held at +21°C, waxwings acclimated to –20°C more than tripled their daily food intake. Mass of digestive organs increased by 22–53%, but rates of enzyme activity and nutrient uptake per unit of small intestine did not change significantly. Retention time of digesta declined slightly, and there was a small decrease in digestive efficiency. As predicted, the main adjustment to increased energy requirements and food intake was an increase in gut length, mass, and volume which largely compensated for increased digesta flow at high intake rates. However, we detected a small reduction in retention time and digestive efficiency in waxwings with high intakes which suggests that these waxwings may be unable to further increase their gut size (i.e., that the increase in gut size was maximal). If adjustments involving gut size require weeks of acclimation time, migration patterns and the pace of migration in birds could be influenced by time required for preparation of the gut. J. Exp. Zool. 283:394–407, 1999. © 1999 Wiley-Liss, Inc.