Optimal Hydropower Generation Under Climate Change Conditions for a Northern Water Resources System

This paper examines climate change impacts on the water resources system of the Manicouagan River (Québec, Canada). The objective is to evaluate the performance of existing infrastructures under future climate projections and the associated uncertainties. The main purpose of the water resources system is hydropower production. A reservoir optimization algorithm, Sampling Stochastic Dynamic Programming (SSDP), was used to derive weekly operating decisions for the existing system subject to reservoir inflows reflecting future climate, for optimum hydropower production. These projections are simulations from the SWAT hydrologic model for climate change scenarios for the period from 2010 to 2099. Results show that the climate change will alter the hydrological regime of the study area: earlier timing of the spring flood, reduced spring peak flow, and increased annual inflows volume in the future compared to the historical climate. The SSDP optimization algorithm adapted the operating policy to the future hydrological regime by adjusting water reservoir levels in the winter and spring, and increasing the release through turbines, which in the end increased power generation. However, there could be more unproductive spills for some power plants, which would decrease the overall efficiency of the existing water resources system.     

STREAM RESTORATION AND CRIBWALL PERFORMANCE: A CASE STUDY OF CRIBWALL MONITORING IN SOUTHERN ONTARIO

Stream restoration focusing on adaptable natural and inert material use has been implemented through soil bioengineering designs aimed at the stabilization of urbanized streams. Within each design application materials such as large wood, sediment fill and vegetation must be suited to diverse settings. This paper discusses the application of cribwalls as soil bioengineering designs found in two Southern Ontario watersheds and the criteria that influence their performance. Field measurements of cribwall cuttings, sediment sampling, erosion pin monitoring, and computer‐generated stream power analysis are used to compare design performance at several sites. It is determined that the technical specifications of the design and site characteristics such as stream power distribution, sediment, and channel planform are equally involved in long‐term streambank stability. The results indicate that cribwalls with dense cutting growth perform well on streambanks that offer a greater amount of soil cohesion, nutrients, and infiltration in the mid and upper sections of the bank. In streams with moderate channel slopes and stream power distribution that is above the watershed mean, streams with well‐developed floodplains, sinuous channel planforms, and low bank height ratios perform better than those that are confined, straightened, and have greater bank height ratios. Throughout the comparison of several cribwall sites, the implication of this work is to demonstrate how to assess the fitness of similar soil bioengineering designs for application to diverse stream settings and to further validate their significance in stream restoration as designs that are multifunctional. Copyright © 2013 John Wiley & Sons, Ltd.     

In situ measurement of lithium mass transfer during charging and discharging of a Ni–Sn alloy electrode

The charging (lithiation) and discharging (delithiation) of a Ni–Sn alloy electrode was examined by means of holographic interferometry and laser scanning confocal microscopy (LSCM). The developing concentration profile of Li⁺ ion during discharging (delithiation) of the Ni–Sn alloy electrode agreed reasonably well with the prediction based on transient diffusion theory, indicating that the cell configuration successfully suppressed natural convection due to the electrochemical reaction. The morphological variation of Ni–Sn alloy electrode during charge/discharge cycle could be observed very clearly by in situ LSCM. It was found that the contraction of active material during the discharge (delithiation) initiates cracks in the Ni–Sn alloy electrode.     

Novel alkaline earth silicate sealing glass for SOFC: Part II. Sealing and interfacial microstructure

This is the second part of a study of a novel Sr–Ca–Ni–Y–B silicate sealing glass for solid oxide fuel cells (SOFC). Part I of the study addresses the effect of NiO on glass forming, thermal, and mechanical properties, and is presented in the preceding paper. In this paper (part II), candidate composite glass with 10 vol.% NiO was tested for sealing standard coupons of Ni/YSZ anode-supported YSZ electrolyte bilayer and metallic interconnect Crofer22APU at various temperatures. Samples sealed at the highest temperature (1050 °C) showed hermetic seal after fully reduction and 10 thermal cycles. The interfacial microstructure characterization showed no distinct reactions at the interfaces of glass/YSZ or glass/metal, though some segregation of Ni was found along the glass/metal interface. Possible reactions were discussed. Overall the composite glass with 10 vol.% NiO appeared to be a good candidate for SOFC sealing.     

Modern Methods of Torque Control on Two-Drum Winders

This paper will deal with various methods of torque control for two-drum winders, some that have been more common in the past and others that have come into use in recent years. Before looking into specific methods of torque control, consideration will be given as to just what function the winder (any winder) performs, the type of operation required on two drum winders to accomplish this function, and how torque control can give this desired operation. Other factors influencing the quality of the rewound roll such as sheet quality, back-stand tension control, and rider roll pressure control will be discussed briefly. Areas (including grades and quality of web) where high back-stand tension or rider roll pressure cannot be utilized for roll density and therefore roll quality will be explained to emphasize the need for positive dependable torque control. Various methods of torque control will be considered along with advantages and disadvantages of each. Finally, results of automatic torque control for two specific installations will be discussed indicating the improved roll quality and ease of operation that has been obtained.     

Uplink–downlink duality with regard to constraints imposed in practice

The uplink–downlink duality is reviewed with regard to constraints imposed on the transmission schemes in practice. In particular, the effects of non-Gaussian signaling, the use of implementable precoding schemes, and the availability of only imperfect channel state information at the central base-station are analyzed and discussed. The sources for violating the uplink–downlink duality in practical schemes are identified, and it is shown under which setting still the same (but not optimum) performance of both transmission directions can be achieved. Besides treating signal-to-interference plus noise ratios, as usually done, the duality is studied with respect to bit error rate, a parameter more relevant in practical applications.     

Dissolution kinetics of dehydroxylated nickeliferous goethite from limonitic lateritic nickel ore

The dissolution kinetics in 2 M H₂SO₄ of variously dehydroxylated nickeliferous goethites was investigated for five oxide-type lateritic nickel deposits. Goethite was the main constituent with minor amounts of quartz, talc, kaolinite and Mn oxides. Dissolution of Fe from heated materials followed the Kabai equation. There was a 9–34-fold increase in the Kabai dissolution rate constant (k) for samples heated at 340–400 °C due to both the increased surface area (1.5–2.6 fold) and higher density of structural defects (5–10 fold) in the variously dehydroxylated products. The presence of structural Al and Cr in goethite appears to reduce dissolution rate possibly through the greater M³⁺–OH, O bond strength relative to Fe³⁺, Ni²⁺–OH, O. Nickel showed congruent dissolution with Fe indicating that Ni was uniformly incorporated in the goethite structure. Pre-heating goethite to 600–800 °C for 30 min resulted in incongruent dissolution of Fe and Ni. It is postulated that some Ni is ejected from the neo-formed hematite structure and resides on the crystal surface or in voids. These results may contribute to the development of more efficient procedures for Ni extraction including heap leaching of lateritic nickel ores.     

Parenting moderates a genetic vulnerability factor in longitudinal increases in youths' substance use.

The authors used a longitudinal, prospective design to investigate a moderation effect in the association between a genetic vulnerability factor, a variable nucleotide repeat polymorphism in the promoter region of 5HTT (5-HTTLPR), and increases in youths' substance use. The primary study hypothesis predicted that involved-supportive parenting would attenuate the link between the 5-HTTLPR polymorphism and longitudinal increases in substance use. African American youths residing in rural Georgia (N = 253, mean age = 11.5 years) provided 4 waves of data on their own substance use; the mothers of the youths provided data on their own parenting practices. Genetic data were obtained from youths via saliva samples. Latent growth curve modeling indicated that 5-HTTLPR status (presence of 1 or 2 copies of the s allele) was linked with increases in substance use over time; however, this association was greatly reduced when youths received high levels of involved-supportive parenting. This study demonstrates that parenting processes have the potential to ameliorate genetic risk. (PsycINFO Database Record (c) 2010 APA, all rights reserved)