Field aligned current observations in the polar cusp ionosphere

Vector magnetic field measurements made during a sounding rocket flight in the polar cusp ionosphere show field fluctuations in the lower F-region which are interpreted as being caused by the payload's passage through a structured field aligned current system. The field aligned currents have a characteristic horizontal scale size of one kilometer. Analysis of one large field fluctuation gives a current density of 0.0001 amp/m sq

A performance evaluation framework for building fault detection and diagnosis algorithms

Fault detection and diagnosis (FDD) algorithms for building systems and equipment represent one of the most active areas of research and commercial product development in the buildings industry. However, far more effort has gone into developing these algorithms than into assessing their performance. As a result, considerable uncertainties remain regarding the accuracy and effectiveness of both research-grade FDD algorithms and commercial products—a state of affairs that has hindered the broad adoption of FDD tools. This article presents a general, systematic framework for evaluating the performance of FDD algorithms. The article focuses on understanding the possible answers to two key questions: in the context of FDD algorithm evaluation, what defines a fault and what defines an evaluation input sample? The answers to these questions, together with appropriate performance metrics, may be used to fully specify evaluation procedures for FDD algorithms

Preliminary Investigation of Novel Bone Graft Substitutes based on Strontium-Calcium-Zinc-Silicate Glasses

Bone graft procedures typically require surgeons to harvest bone from a second site on a given patient (Autograft) before repairing a bone defect. However, this results in increased surgical time, excessive blood loss and a significant increase in pain. In this context a synthetic bone graft with excellent histocompatibility, built in antibacterial efficacy and the ability to regenerate healthy tissue in place of diseased tissue would be a significant step forward relative to current state of the art philosophies. We developed a range of calcium-strontium-zinc-silicate glass-based bone grafts and characterized their structure and physical properties, then evaluated their in vitro cytotoxicity and in vivo biocompatibility using standardized models from the literature. A graft (designated BT109) of composition 0.28SrO/0.32ZnO/0.40 SiO2 (mol fraction) was the best performing formulation in vitro shown to induce extremely mild cytopathic effects (cell viability up to 95%) in comparison with the commercially available bone graft Novabone® (cell viability of up to 72%). Supplementary to this, the grafts were examined using the standard rat femur healing model on healthy Wister rats. All grafts were shown to be equally well tolerated in bone tissue and new bone was seen in close apposition to implanted particles with no evidence of an inflammatory response within bone. Complimentary to this BT109 was implanted into the femurs of ovariectomized rats to monitor the response of osteoporotic tissue to the bone grafts. The results from this experiment indicate that the novel grafts perform equally well in osteoporotic tissue as in healthy tissue, which is encouraging given that bone response to implants is usually diminished in ovariectomized rats. In conclusion these materials exhibit significant potential as synthetic bone grafts to warrant further investigation and optimisation. © 2008 Springer Science+Business Media, LLC

RSAT™ process development for post-combustion CO2 capture: Scale-up from laboratory and pilot test data to commercial process design

AbstractIt is believed that a RSAT™ (Regenerable Solvent Absorption Technology) process is the most viable nearterm technology for post-combustion CO2 capture from power plant flue gas. The Babcock & Wilcox Power Generation Group, Inc. (B&W) has deployed a suite of research tools to evaluate and develop the CO2 scrubbing technology, including laboratory, pilot-scale, and simulation modeling capabilities. Since the construction and operation of test facilities require significant resources, it is essential to effectively utilize these research tools by choosing a scale-up approach which provides robust design data for a commercial process while minimizing the amount of experimentation required.The scale-up protocol used for RSAT CO2 scrubbing processes was rigorously developed using rate-based modeling concurrent with acquiring fundamental laboratory and pilot plant data for process validation. These development activities were not conducted in series but rather overlapped to yield an optimized commercial CO2 scrubbing process in a reasonable time frame with a high degree of design confidence [1,2].This paper presents the scale-up protocol used in evaluating the RSAT process which encompasses both laboratory and pilot-scale testing as well as rate-based modeling to achieve a commercial-scale RSAT process design. This document demonstrates the qualification of test data from a packed tower scale-up point of view. Solvent screening research activities recently conducted within B&W successfully demonstrate the scale-up protocol used for RSAT process development. The time and cost of process development can be significantly reduced through rigorous rate-based modeling in conjunction with laboratory experiments and pilot plant validation

Concept selection for advanced low-emission coal fired boiler

The Babcock & Wilcox Company (B&W), under contract to the US Department of Energy (DOE) with subcontract to Physical Sciences, Inc. (PSIT), the Massachusetts Institute of Technology (MIT) and United Engineers and Constructors (UE&C) has begun development of an advanced low-emission boiler system (LEBS). The initial phase of this multi-phase program required a thorough review and assessment of potential advanced technologies and techniques for control of combustion and flue gas emissions. Results of this assessment are presented in this paper

Advanced Emissions Control Development Program

The primary objective of the Advanced Emissions Control Development Program (AECDP) is to develop practical, cost-effective strategies for reducing the emissions of hazardous air pollutants (HAPs, or air toxics) from coal-fired boilers. This objective is being met by identifying ways to effectively control air toxic emissions through the use of conventional flue gas cleanup equipment such as electrostatic precipitators (ESPs), fabric filters (fabric filters), and wet flue gas desulfurization (wet FGD) systems. Development work initially concentrated on the capture of trace metals, hydrogen chloride, and hydrogen fluoride. Recent work has focused almost exclusively on the control of mercury emissions

Giardiasis: Impact on child growth

Artículo científico -- Universidad de Costa Rica. Instituto de Investigaciones en Salud, 1986Chronic disorders of the gastrointestinal tract may impair physical growth during infancy and childhood. Growth retardation has been particularly well documented in children with Crohn's disease and coeliac disease in which growth retardation may occur in the absence of gastrointestinal symptoms. Recurrent and persistent infection in infancy and childhood is also associated with growth retardation, the major offenders being infections of the respiratory and gastrointestinal tracts. The pathogenic mechanisms of growth disturbance in chronic disease are poorly understood. Possible candidates include reduced dietary intake as a result of anorexia, food withholding following cultural practice or physician's advice and increased energy expenditure associated with fever and infection. Nutritional deprivation due to intestinal malabsorption is probably a less important factor in inflammatory bowel disease but may be more relevant in coeliac disease and infective disorders of the intestine. Although Giardia is now an established intestinal pathogen its relationship to child growth and development has not been clearly defined. However, giardiasis (1) frequently affects infants and children; (2) is known to cause morphological damage of the small intestine and malabsorption of a variety of nutrients 15 ; (3) is not always a self-limiting infection and may persist for many weeks or months; (4) has been shown to impair physical growth in some individuals with Giardia infection. There is, however, very little population-based data on the effect of Giardia infection on physical growth during infancy and childhood and thus the impact of this parasite at a community level is largely unknown. The parasite may be excreted by apparently asymptomatic individuals and thus before widespread strategies for the control of this infection are introduced the extent of its clinical impact must be established.Universidad de Costa Rica. Instituto de Investigaciones en Salud.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

Wavelets and graph C∗C^*-algebras

Here we give an overview on the connection between wavelet theory and representation theory for graph $C^{\ast}$-algebras, including the higher-rank graph $C^*$-algebras of A. Kumjian and D. Pask. Many authors have studied different aspects of this connection over the last 20 years, and we begin this paper with a survey of the known results. We then discuss several new ways to generalize these results and obtain wavelets associated to representations of higher-rank graphs. In \cite{FGKP}, we introduced the "cubical wavelets" associated to a higher-rank graph. Here, we generalize this construction to build wavelets of arbitrary shapes. We also present a different but related construction of wavelets associated to a higher-rank graph, which we anticipate will have applications to traffic analysis on networks. Finally, we generalize the spectral graph wavelets of \cite{hammond} to higher-rank graphs, giving a third family of wavelets associated to higher-rank graphs

Magnetospheric multiprobes: Investigations and instrumentation

The multiprobe scientific objectives are to: (1) determine the spatial structure of plasma phenomena such as the aurora, convection reversals, and ion troughs; (2) separate spatial and temporal variations in these phenomena; (3) determine field aligned current densities; (4) perform multiple point analysis of particle beams, wave fields, and plasma clouds that are injected into the ionosphere and magnetosphere by Spacelab active experiment facilities. Trade studies described include: instrument accommodations, power, attitude determination, electric field antennas, storage and ejection, thermal control, tracking communications, command and data management, payload and mission specialist support, functional objectives, and orbital analysis