Effective Cell-Centred Time-Domain Maxwell's Equations Numerical Solvers

This research work analyses techniques for implementing a cell-centred finite-volume time-domain (ccFV-TD) computational methodology for the purpose of studying microwave heating. Various state-of-the-art spatial and temporal discretisation methods employed to solve Maxwell's equations on multidimensional structured grid networks are investigated, and the dispersive and dissipative errors inherent in those techniques examined. Both staggered and unstaggered grid approaches are considered. Upwind schemes using a Riemann solver and intensity vector splitting are studied and evaluated. Staggered and unstaggered Leapfrog and Runge-Kutta time integration methods are analysed in terms of phase and amplitude error to identify which method is the most accurate and efficient for simulating microwave heating processes. The implementation and migration of typical electromagnetic boundary conditions. from staggered in space to cell-centred approaches also is deliberated. In particular, an existing perfectly matched layer absorbing boundary methodology is adapted to formulate a new cell-centred boundary implementation for the ccFV-TD solvers. Finally for microwave heating purposes, a comparison of analytical and numerical results for standard case studies in rectangular waveguides allows the accuracy of the developed methods to be assessed

Liminal to Liminoid, in Play, Flow, and Ritual: An Essay in Comparative Symbology

Paper by Victor Turne

Transform methods for precision continuum and control models of flexible space structures

An open loop optimal control algorithm is developed for general flexible structures, based on Laplace transform methods. A distributed parameter model of the structure is first presented, followed by a derivation of the optimal control algorithm. The control inputs are expressed in terms of their Fourier series expansions, so that a numerical solution can be easily obtained. The algorithm deals directly with the transcendental transfer functions from control inputs to outputs of interest, and structural deformation penalties, as well as penalties on control effort, are included in the formulation. The algorithm is applied to several structures of increasing complexity to show its generality

Speed

We investigate the determinants of driving speed in large us cities. We first estimate city level supply functions for travel in an econometric framework where both the supply and demand for travel are explicit. These estimations allow us to calculate a city level index of driving speed and to rank cities by driving speed. Our data suggest that a congestion tax of, on average, about 1.5 cents per kilometer yields welfare gains of about 30 billion dollars per year, that centralized cities are slower, that cities with ring roads are faster, and that the provision of automobile travel in cities is subject to decreasing returns to scale

Speed

We investigate the determinants of driving speed in large us cities. We first estimate city level supply functions for travel in an econometric framework where both the supply and demand for travel are explicit. These estimations allow us to calculate a city level index of driving speed and to rank cities by driving speed. Our data suggest that a congestion tax of, on average, about 1.5 cents per kilometer yields welfare gains of about 30 billion dollars per year, that centralized cities are slower, that cities with ring roads are faster, and that the provision of automobile travel in cities is subject to decreasing returns to scale

Method development in inverse modeling applied to supercritical fluid extraction of lipids

Modeling of the supercritical fluid extraction of solid materials is an important aspect in order to understand and predict the process. A comparison of two empirical models, two semi-empirical models and two mechanistic models is performed using calibration of single experiments. It is concluded that the best fit is obtained using a simple empirical expression. Furthermore, single calibrations did not generate reliable parameters with physical meaning and a methodology is proposed for inverse modeling with complete calibration using several experiments. The experimental dataset contained 29 extractions of lipids from crushed linseeds with varying temperatures, pressures and flow rates. A general rate model and a proposed extension of the hot ball model were evaluated for this purpose. The methodology includes data acquisition, model structure estimation, model calibration and a cross-validation. In general, it was found that the solubility model of Sovová outperformed the other evaluated correlations, and for the general rate model the Toth partition isotherm was also found in the top model structures. However, no generalization could be made regarding the correlations describing the Nernst diffusion layer and diffusivity

The thyroid secretion rate in the mouse and its relation to various physiological processes

Publication authorized may 12, 1948Digitized 2007 AES.Includes bibliographical references (pages 52-62)

Changes in the activity of some enzymes in the rat hemidiaphragm hypertrophying as a consequence of unilateral phrenicectomy

The post-denervation hypertrophy of the rat hemidiaphragm has been studied for up to 15 days after nerve section. The denervated tissue increases in wet weight to a maximum at 5 days of 40 % over its initial weight; by the 15th day the tissue has atrophied to below the control value. Measurements have been made throughout the hypertrophy period of the activities of some enzymes characteristic of particular aspects of muscle metabolism. In additions concentrations of glycogen from fed, and overnight fasted rats; of myoglobin; and of free amino acid concentrations in the denervated tissue have also been studied. Methods are described for the use in rats of the anaesthetic Halothane so as to preserve muscle glycogen concentrations and to prevent stress-mediated activation of phosphorylase a levels. Unilateral phrenicectomy causes a decrease in glycogen concentration and contents a decrease of total glycogen phosphorylase activity is also found, but total content of phosphoglucorautase increases slightly, Hexokinase and phosphorylase contents increase so that their concentrations are maintained. The validity of the hexokinase/ phosphorylase ratio as an indicator of fibre composition in pathological tissues is questioned. Phosphohexoisomerase activity remains constant for 1 week after denervation, then decreases, but glyceraldehyde phosphate dehydrogenase & lactate dehydrogenase demonstrate increased contents at 7 days before they decrease; the responses of the dehydrogenases may be related to the reported proliferation of the sarcoplasmic reticulum. No significant change is observed in the lactate dehydrogenase isoenzyme proportions until 7 days when a decrease of H-type subunits is indicated; 3 days later though control proportions are regained. Content of malate dehydrogenase, VAD-, & NADP-specific dehydro-genases demonstrate rapid decreases after nerve section to roughly half the initial levels at 3 days after nerve section. Glutamate dehydrogenase concentration also decreases in the early stages of the hypertrophy, but later increases when protein catabolism becomes a significant process. These decreases art in 'accord with the reported fragmentation of the mitochondria. Glucose G-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase concentrations increase dramatically to a peak within the first few days after nerve section. The increased enzyme capacity could be responsible for provision of nentose phosphates for nucleotide and nucleic acid synthesis. Total creatine kinase activity remains constant for up to 5 days before a decline in observed; adenylate kinase & adenylate deaminase show increased contents. The responses are interpreted in terms of possible involvement in increased adenine nucleotide production. The validity of the adenylate kinase/creatine kinase activity- ratio for the identification of physiologically distinct muscles in questioned. Content of glutathione reductase shows two small peaks of increased activity at 3 and 10 days after denervation. Thus unlike other denervated or dystrophic muscles, the responses o NADP-linked dehydrogenoses are not similar. Myoglobin content increases slowly during the hypertrophy only reaching a peak of 20 % over control levels at 10 days. Concentration in the early stages is thus decreased but rises after 5 days. The response, as well as the changes in lactate dehydrogenase isoenzyme proportions, is interpreted in terms of an increased blood flow through the denervated tissue. Total free amino acid concentration in the denervated tissue is increased; responses of the individual species are interpreted in terms of possible modes of metabolism in the tissue. The responses in the denervated hemidiaphragm are interpreted in terms of a hypertrophy of the "red" &/or "intermediate" fibre types; suggestions are made as to possible causes for the responses

The thyroid hormone secretion rate of domestic fowls as determined by radio-iodine techniques

The bulletin is a report on Department of Dairy Husbandry Research Project No. 80, 'Endocrine-Genetics'--P. [2].Digitized 2007 AES.Includes bibliographical references (pages 88-96)