1,507 research outputs found
Three dimensional extension of Bresenham’s algorithm with Voronoi diagram
Bresenham’s algorithm for plotting a two-dimensional line segment is elegant and efficient in its deployment of mid-point comparison and integer arithmetic. It is natural to investigate its three-dimensional extensions. In so doing, this paper uncovers the reason for little prior work. The concept of the mid-point in a unit interval generalizes to that of nearest neighbours involving a Voronoi diagram. Algorithmically, there are challenges. While a unit interval in two-dimension becomes a unit square in three-dimension, “squaring” the number of choices in Bresenham’s algorithm is shown to have difficulties. In this paper, the three-dimensional extension is based on the main idea of Bresenham’s algorithm of minimum distance between the line and the grid points. The structure of the Voronoi diagram is presented for grid points to which the line may be approximated. The deployment of integer arithmetic and symmetry for the three-dimensional extension of the algorithm to raise the computation efficiency are also investigated
CONSTRAINING THE GEOMETRY, SIZE SCALE AND PHYSICAL CONDITIONS OF OUTFLOWING BROAD ABSORPTION LINE REGIONS IN QUASARS
Quasars are known for generating luminosities of up to 1047 erg/s in volumes of scales smaller than 2x10^15 cm. The optical/UV continuum emission is generally believed to
arise from a rotating accretion disk (AD) surrounding a supermassive black hole (SMBH) of ~10^8Msun. Such emission can be calculated by treating the AD as a multi-temperature blackbody. While the continuum emitting region is well defined, the properties, location and kinematics of the broad emission line regions (BELRs) and broad absorption line regions (BALRs) remain unclear. On one hand, the reverberation mapping technique can give constraints on the location of the BELRs, but not the kinematics. On the other hand, the line-of-sight kinematics of the BALRs is directly observable, but their locations are not well constrained, resulting in a large range of inferred distances, from 0.01 pc to tens of kpc. Therefore, I combined observational results to investigate the geometry, size, and physical conditions of the BELRs and BALRs. I verified that the Ly alpha and CIV BELRs are located at a similar distance. Using these findings, I was able to constrain the size of the Ly alpha BELR and place a lower limit on the size of the Nv BALR. I built an empirical model with the optical/UV continuum emission from the AD, the BELR from the chromosphere of the AD, and the outflowing BALR. In
the continuum region, I found that over 95 percent of the total flux comes from the region at ~125rg, where rg is the gravitational radius of the SMBH. For the BELRs, I computed a disk-wind model with relativistic effects to explain the often-observed single-peaked BEL profiles. However, I show that such a model cannot explain the observed blue asymmetries in the high-ionization BELs or their blueshifted peaks relative to low-ionization BELs. Using results on time variability of BALR gas, and assuming the variability is caused by the gas moving perpendicular across the line-of-sight over a time scale of about a year, I conclude that the BALR gas is clumpy or filamentary, with the clumps having a size scale of ~10^3 pc
Veterinary Medicine in China
The profession of veterinary medicine in old China was not properly respected. However, in the new China the government has been paying much attention to the livestock industry. During the past decade, several institutions designed for veterinary science research and the manufacture of biological products have been set up by the government; veterinary courses have been added to several agricultural colleges. Veterinary medicine has been especially emphasized since the war
Economic Growth and Infrastructure Investments in Energy and Transportation:A Causality Interpretation of China’s Western Development Strategy
Were the large investments in energy and transportation infrastructure effective in fostering economic growth? Or did economic growth trigger these infrastructure developments? To answer these questions, we develop a simple model of production capacity constraints and use China's Western Development Strategy (WDS) as an example to investigate how the relationships among energy investment, transportation infrastructure expansion and economic growth differ in the pre- and post-WDS periods. Our Granger causality analysis uses a panel data sample for China's 30 provinces in the Western and non-Western regions for the period of 1991-2012. We find Granger causality only in the post-WDS period from transportation infrastructure expansion to economic growth and from economic growth to energy investment. These results suggest energy and transportation capacity constraints in the post-WDS period but not the pre-WDS period. Their policy implication is that China should continue its energy and transportation infrastructure investments with improved coordination.School of Accounting and Financ
The Heideggerian Legacy in Paul Tillich's Ontology and Theological Anthropology
This dissertation demonstrates that Martin Heidegger’s fundamental ontology was a significant influence on Paul Tillich’s understanding of divine and human realities, by showing that Tillich adopted Heidegger’s concern for being and his approach to the question of being. Heidegger’s philosophical influence on Tillich’s thought has been well known. But the specific nature of this influence and its implications has not hitherto been documented. Neither has the issue received much attention in the secondary literature on Heidegger. The study consists of two parts. The first (Chapters 2-3) provides an intensive historical and philosophical survey of the background of the Tillich-Heidegger encounters. The second part (Chapters 4-7) is an analysis of the origins and development of Tillich’s theological and philosophical thought particularly in terms of his anthropology and ontology under the influence of Heidegger. The second part highlights the Heideggerian claims of human existentiality inherent in Tillich’s theological system, as distinguished from Tillich’s own theological creativity and philosophical originality. Chapter 2 identifies Tillich’s concern with existentialism as Heideggerian. Chapter 3 investigates the decisive and historically unique period of encounter between Tillich and Heidegger, the years 1924-1925, when they both taught at the University of Marburg. Chapter 4 underscores the important elements of Heideggerian existentialism in Tillich’s early theological program. Chapter 5 illustrates the challenge of modern existentialism that Tillich confronted in the person of Heidegger and discusses Tillich’s subordination of his metaphysics of meaning to the Heideggerian metaphysics of being. Chapter 6 suggests that Tillich’s choice of existentialism is indebted to Heidegger’s critical analysis of the relationship between philosophy and theology. Chapter 7 explores a central aspect of Tillich’s theological anthropology, the concept of finitude, in relation to Heidegger’s project of existential analysis of Dasein. The study shows that the Tillich-Heidegger connection is not a mere coincidental structural similarity and that Tillich’s call for transcending theism reflects Tillich’s interpretation of Heidegger’s philosophy as theologically oriented. The study thereby establishes a point of departure from which to explore on a deeper level the philosophical foundation of Tillich’s theological endeavor and vision
Adsorption and Electrochemistry of BIS-1, 10-Phenanthroline Complexes of Copper (I,II) and Fungal Laccase A
This thesis is an outcome of the efforts directed toward the theme "Electrocatalysis of dioxygen reduction by copper- containing molecules adsorbed on graphite electrodes."
In the first part, an electrochemical measurement of the rate of electron exchange between Cu(phen)2+ adsorbed on graphite and Cu(phen)2++ in solution is described. The rate constant was estimated to be ca. 105 M-1 s-1 by using rotating disk voltammetry. The origin of the previously reported but widely discrepant values (5 x 107 M-1 s-1 and 50 M-1 s-1) in the literature is discussed, and a new estimate of ca. 104 M-1 s-1 is obtained by applying Marcus theory in a form that allows explicitly for differences in reorganization energy between the oxidized and reduced halves of the reacting redox couples. The electrocatalytic studies of dioxygen reduction by Cu(phen)2+ could not be done due to the low signal-to-noise ratio.
In the second part, the bioelectrocatalytic reduction of molecular oxygen by reduced fungal laccase A immobilized on pyrolytic graphite is described. The reduction produces exclusively water in the potential range studied (< 0 V vs. SSCE). The catalytic activity reaches its maximum at pH 3~4, and the lower limit on rate constant for the reduction in this pH range was estimated to be 1.5 x 104 M-1 s-1.
Three appendices describe (i) potential step hydrodynamic chronocoulometry, (ii) a new method to determine the self- exchange rate constant for the redox couple in which the coordination numbers depend on the oxidation states, and (iii) a novel electrochemical method of detecting H2O2.</p
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Enhanced sensitivity photodetector having a multi-layered, sandwich-type construction
A photoconductive member is provided with increased sensitivity to radiation incident thereupon and with increased photo-yield in response thereto by means of a multi-layered, sandwich-type construction based upon the provision of successive layers of sensitizing material over corresponding successive layers of conducting material. The photoconductive member comprises at least two composite layers formed one above the other on an insulating substrate, each composite layer comprising a first layer of material capable of conducting charge and a second layer of material comprising polar molecules disposed upon the charge-conducting material layer in such a manner that successive layers of polar molecules are adsorbed and retained in an oriented fashion on successive layers of the charge-conducting material. In combination, the alternating layers of charge-conducting material and polar molecules increase photo-yield in response to a given quantum of incident radiation and also increase the range of wavelength of incident radiation to which the photoconductive member is responsive. The sandwich-type construction permits photoconductor sensitivity to be increased as a function of the number of layers of conducting material and polar molecules used to form the photoconductive surface. The multi-layered construction also exhibits reduced sensitivity to the degrading effects of impurities, is adapted to convenient fabrication, and exhibits extended lifetime.Board of Regents, University of Texas Syste
Price Responsiveness of Residential Demand for Natural Gas in the United States
While price responsiveness of residential demand for natural gas has important implications on resource planning and energy modelling, its estimates from prior studies are very diverse. Applying panel data analysis and five parametric specifications to monthly data for the lower 48 states in 1990–2019, we estimate own-price elasticities of residential demand for natural gas in the United States (US). Using results from cross-section dependence (CD) test, panel unit root tests, panel time-series estimators, and rolling-window analysis, we document: (1) the statistically significant (p-value ≤ 0.05) static own-price elasticity estimates are −0.271 to −0.486, short-run −0.238 to −0.555 and long-run −0.323 to −0.796; (2) these estimates vary by elasticity type, sample period, parametric specification, treatment of CD and assumption of partial adjustment; (3) erroneously ignoring the highly significant (p-value < 0.01) CD shrinks the size of these estimates that vary seasonally, regionally, and nonlinearly over time; and (4) residential natural gas shortage costs decline with the size of own-price elasticity estimates. These findings suggest that achieving deep decarbonization may require strategies that do not rely solely on prices, such as energy efficiency standards and demand-side-management programs. Demand response programs may prove useful for managing natural gas shortages
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