Hardware problems encountered in solar heating and cooling systems

Numerous problems in the design, production, installation, and operation of solar energy systems are discussed. Described are hardware problems, which range from simple to obscure and complex, and their resolution

Teacher self-perceptions and student academic engagement in elementary school mathematics.

This study examined the relationship between elementary students’ academic engagement in mathematics and their teachers’ self-perceptions in mathematics. Early success in mathematics is seen as crucial for later success academically and professionally. Framed in Social Cognitive Theory this study sought to build on past research studies, which have found that student affective characteristics such as academic engagement, comprised of both behavioral and emotional engagement, vary across genders and ability levels. This study sought to use a number of control and independent variables to examine academic engagement in students and the relationship of that engagement to teachers’ mathematics self-concept and teaching self-efficacy. Due to the nested nature of the data, hierarchical linear modeling was used to analyze the data. Key findings indicated that, while classes of students vary on levels of academic engagement, in general this variability was not explained by the teacher’s self-perceptions. However, when it comes to behavioral engagement, one of the two components of academic engagement studied here, in mathematics class, arguably a characteristic that might be particularly influenced by teachers, girls and boys differ significantly not only in their engagement (with girls in this study reporting statistically significantly more engagement than boys) but also in the way in which their engagement relates to teacher self-perceptions. In fact, teacher self-perceptions account for approximately 62% of the difference between girls and boys on their reported levels of behavioral engagement. Thus, the results of this study support the theory that, if one is interested in helping close the STEM gap for girls, there is a need for more mathematically strong teachers of female students even in the early grades. Suggestions for future research including looking at what class-level factors might explain the between-class variability in academic engagement, and further exploring the finding that differences in gender slopes were partially explained by teacher self-perceptions

Detecting Heatsink Types for Socketed Processors

Servers often are designed to support a socketed processor in order to allow the end user the ability to customize their compute solution for their needs. Server processor vendors offer a variety of different processor models that can be installed. These various processor models can have differing technical specifications that include core count, cache size, operating frequency limitations, memory capacity, as well as power and thermal cooling requirements. An individual server design could easily support a range of processor models from those that have few cores, providing low performance, all the way up to dozens of cores that providing high performance. Since compute resources such as cores consume power, the range of processor power can be as wide as 200W. To keep costs of a total solution down, different heatsinks are often designed and sold to support this wide range: cheap extruded aluminium heatsinks for lower performing CPUs and expensive heat piped heatsinks for higher performing CPUs

Extended Water Quality Monitoring of the Lincoln Lake Watershed

For seven years, the Lincoln Lake (Moores Creek and Beatty Branch) watershed was monitored for improvements in water quality resulting from agricultural best management practices (BMP) implemented to reduce nutrient transport. During the first three years of monitoring (1991 to 1994), nitrogen transport declined significantly (Edwards et al., 1994, 1996, and 1997) under both base and storm flow conditions. This decline in nitrogen transport was again observed in the three-year period following 1994 (Vendrell et al. 1998). This monitoring effort has demonstrated that water quality bas improved in the Lincoln Lake watershed. However, since the nitrogen transport continued to decline and there was some indication that phosphorus may begin to decline, monitoring was extended for another year (1998)

A Contribution to the Flora of the Lower Coal-measures of the Parish of Halifax, Yorkshire

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Narrative Distance in the Works of George Gordon, Lord Byron, and Jonathan Swift, or A Digression in Praise of Digressions

This thesis reviews and discusses narrative distance in the works of George Gordon, Lord Byron, and Jonathan Swift or “A Digression in Praise of Digressions.” Byron takes on multiple roles in his poetry. Swift provided Byron a model for how to negotiate the boundaries of fictional self-fashioning and biographical revelation. Bryon’s technique of presenting a version of himself while simultaneously maintaining narrative distance is a distinct characteristics of Swift’s work. The thesis adapts to an important fact in that Byron, although writing in the age of Romanticism, significantly and unflinchingly sought distance between himself and Romantic figures

Phenomenological model of diffuse global and regional atrophy using finite-element methods

The main goal of this work is the generation of ground-truth data for the validation of atrophy measurement techniques, commonly used in the study of neurodegenerative diseases such as dementia. Several techniques have been used to measure atrophy in cross-sectional and longitudinal studies, but it is extremely difficult to compare their performance since they have been applied to different patient populations. Furthermore, assessment of performance based on phantom measurements or simple scaled images overestimates these techniques' ability to capture the complexity of neurodegeneration of the human brain. We propose a method for atrophy simulation in structural magnetic resonance (MR) images based on finite-element methods. The method produces cohorts of brain images with known change that is physically and clinically plausible, providing data for objective evaluation of atrophy measurement techniques. Atrophy is simulated in different tissue compartments or in different neuroanatomical structures with a phenomenological model. This model of diffuse global and regional atrophy is based on volumetric measurements such as the brain or the hippocampus, from patients with known disease and guided by clinical knowledge of the relative pathological involvement of regions and tissues. The consequent biomechanical readjustment of structures is modelled using conventional physics-based techniques based on biomechanical tissue properties and simulating plausible tissue deformations with finite-element methods. A thermoelastic model of tissue deformation is employed, controlling the rate of progression of atrophy by means of a set of thermal coefficients, each one corresponding to a different type of tissue. Tissue characterization is performed by means of the meshing of a labelled brain atlas, creating a reference volumetric mesh that will be introduced to a finite-element solver to create the simulated deformations. Preliminary work on the simulation of acquisition artefa- - cts is also presented. Cross-sectional and

Compatibility studies of several molten uranium and thorium alloys in niobium, tantalum, and yttrium

Niobium, tantalum, yttrium, and Inconel have been used to contain molten aluminum, lead, tin, zinc, and several of their respective uranium and thorium alloys for various times up to 3000 hours and at temperatures ranging from 600 to 1100° C. Altogether 76 capsule tests were run, almost all in a static isothermal condition. Tantalum showed the best resistance followed by niobium, Inconel, and yttrium respectively. The systems, lead in tantalum and lead in niobium, showed the greatest potentials for possible liquid-metal fuel carrier systems. An alloy of uranium-bismuth-tin contained in tantalum also exhibited promising possibilities . The tabulated test data include a classification of the type of corrosion attack which occurred and a measured value of the amount of corrosive penetration. Each test was also given an arbitrary rating for easy reference comparisons. A number of photomicrographs are included for each set of tests