Equation of State Phase Equilibria Calculations

Mixtures of carbon dioxide and some hydrocarbons will form liquid-liquid-vapor equilibrium at temperatures and pressures considered reservoir conditions. So that carbon dioxide miscible flooding may be properly simulated, accurate modeling of the phase behavior is necessary. An algorithm has been developed which is capable of predicting the two-phase and liquid-liquid-vapor equilibrium shown by C02-hydrocarbon mixtures. The algorithm conducts phase stability analysis calculations in series with flash calculations using the Peng-Robinson equation of state to model fluid behavior of all phases present. Example calculations were made of CO2 mixtures with normal alkanes which show liquid-vapor, liquid-liquid, and also liquid-liquid-vapor behavior. An example calculation was also made for a mixture of CO2 with a reservoir oil.Petroleum and Geosystems Engineerin

A Search For Balance In The Discovery Of Esi Since December 1, 2006

An explosion in the amount and discovery of electronically stored information (ESI) threatens to clog the federal court system and make judicial determination of the substantive merits of disputes an endangered species. It is interesting that this information discovery explosion has skipped over Rule 1 of the Federal Rules of Civil Procedure, which provides in part that the federal rules “shall be construed and administered to secure the just, speedy, and inexpensive determination of every action.

Geology and Mineral Deposits of the Southwest Quarter of the Tanacross D-1 Quadrangle, Alaska

The study area is in the northeast corner of the Tanacross quadrangle, east-central Alaska. Known as the Interior Porphyry belt, it lies between the Tintina fault to the north and the Denali fault to the south. Seven major porphyry copper-type deposits have been found within the belt since I969. Because much of the belt was unglaciated during Pleistocene time, the probability of finding a zone of supergene enrichment is enhanced. In Alaska a porphyry copper-type deposit with a supergene zone may improve the current economic status by helping to facilitate amortization of production capital costs. The rocks within the study area consist mainly of Paleozoic or older schists and gneiss units that have been intruded by late Cretaceous-early Tertiary igneous rocks. Limited exposures, residual soils, and thick brush in the Tanacross area have necessitated the use of reconnaissance geochemistry, aeromagnetics, and Landsat imagery to locate areas of potential mineralization. Three such areas were found within the study area; they have been named Pika Canyon, NE Pika Canyon, and Fishhook prospects. The Pika Canyon and NE Pika Canyon prospects have been studied by detailed soil geochemistry, ground magnetics, and geologic and alteration mapping. Only the geology and alteration have been mapped at the Fishhook prospect. Work completed at the three prospects indicates that Pika Canyon and Fishhook prospects represent potential porphyry copper-type deposits, and that NE Pika Canyon is possibly a structurally controlled copper-zinc deposit. At the present stage of exploration the economic potential of these prospects cannot be determined

Motion dazzle:A locust's eye view

Motion dazzle describes high-contrast patterns (e.g. zigzags on snakes and dazzle paint on World War I ships) that do not conceal an object, but inhibit an observer's perception of its motion. However, there is limited evidence for this phenomenon. Locusts have a pair of descending contralateral movement detector (DCMD) neurons which respond to predator-like looming objects and trigger escape responses. Within the network providing input to a DCMD, separate channels are excited when moving edges cause areas of the visual field to brighten or darken, respectively, and these stimuli interact antagonistically. When a looming square has an upper half and lower half that are both darker than background, it elicits a stronger DCMD response than the upper half does alone. However, when a looming square has a darker-than-background upper half and a brighter-than-background lower half, it elicits a weaker DCMD response than its upper half does alone. This effect allows high-contrast patterns to weaken and delay DCMD response parameters implicated in escape decisions, and is analogous to motion dazzle. However, the motion dazzle effect does not provide the best means of motion camouflage, because uniform bright squares, or low-contrast squares, elicit weaker DCMD responses than high-contrast, half dark, half bright squares

A Colour Opponent Model That Explains Tsetse Fly Attraction to Visual Baits and Can Be Used to Investigate More Efficacious Bait Materials

Palpalis group tsetse flies are the major vectors of human African trypanosomiasis, and visually-attractive targets and traps are important tools for their control. Considerable efforts are underway to optimise these visual baits, and one factor that has been investigated is coloration. Analyses of the link between visual bait coloration and tsetse fly catches have used methods which poorly replicate sensory processing in the fly visual system, but doing so would allow the visual information driving tsetse attraction to these baits to be more fully understood, and the reflectance spectra of candidate visual baits to be more completely analysed. Following methods well established for other species, I reanalyse the numbers of tsetse flies caught at visual baits based upon the calculated photoreceptor excitations elicited by those baits. I do this for large sets of previously published data for Glossina fuscipes fuscipes (Lindh et al. (2012). PLoS Negl Trop Dis 6: e1661), G. palpalis palpalis (Green (1988). Bull Ent Res 78: 591), and G. pallidipes (Green and Flint (1986). Bull Ent Res 76: 409). Tsetse attraction to visual baits in these studies can be explained by a colour opponent mechanism to which the UV-blue photoreceptor R7y contributes positively, and both the green-yellow photoreceptor R8y, and the low-wavelength UV photoreceptor R7p, contribute negatively. A tool for calculating fly photoreceptor excitations is made available with this paper, and this will facilitate a complete and biologically authentic description of visual bait reflectance spectra that can be employed in the search for more efficacious visual baits, or the analysis of future studies of tsetse fly attraction

Status and trends of music education in the public secondary schools of Maine.

Thesis (M.A.)--Boston Universit

Magnetism in crystalline rare-earth compounds

In this thesis we investigate the magnetism of a selection of crystalline mate- rials that display fascinating macroscopic properties, largely due to the complex behaviour of rare-earth ions. The technique of choice is diffraction; shown to pro- vide the most lucid of results in this field of research. Neutron powder diffraction, a well established tool for determining magnetic structures, has been employed in order to determine two magnetic structures of the intermetallic R2CoGa8 series. This was the first such study of these materials, which are of great interest as the magnetic exchange interactions of the rare-earth ions compete with the crystal elec- tric field, giving rise to a wealth of magnetic properties tuneable by the choice of rare-earth ion. We then move on to study two of the most extreme multiferroic mate- rials, TbMn2O5 and TmMn2O5. We have developed a new technique for determin- ing electronic state specific magnetic structures through resonant x-ray diffraction, which we have successfully employed in an investigation of the terbium magnetic sub-lattice in TbMn2O5. The outstanding question in many multiferroics regards the exact microscopic mechanisms at play. Due to the huge potential in technology, this has been the subject of intense debate over that past decade. We have shown, through ab-initio computation and the simultaneous measurement of electric polar- isation and magneto-striction, that the exchange-striction model is dominant in the main ferroelectric phase of TbMn2O5 and TmMn2O5. Through ion specific resonant x-ray diffraction measurements, we have clarified the behaviour of the terbium sub- lattice upon the magnetic field induced electric polarisation reversal in TbMn2O5. Furthermore, we have made the discovery of additional incommensurate magnetic diffraction signals, believed to be indicative of the response of magnetic domains to applied magnetic fields

Did the HMO Revolution Cause Hospital Consolidation?

During the 1990s US healthcare markets underwent a significant transformation. Managed care rose to become the dominant form of insurance in the private sector. Also, a wave of hospital consolidation occurred. In 1990, the mean population-weighted hospital Herfindahl-Hirschman Index (HHI) in a Health Services Area (HSA) was .19. By 2000, the HHI had risen to .26. This paper explores whether the rise in managed care caused the increase in hospital concentration. We use an instrumental variables approach with 10-year differences to identify the relationship between managed care penetration and hospital consolidation. Our results strongly imply that the rise of managed care did not cause the hospital consolidation wave. This finding is robust to a number of different specifications.

The Welfare Consequences of Hospital Mergers

In the 1990s the US hospital industry consolidated. This paper estimates the impact of the wave of hospital mergers on welfare focusing on the impact on consumer surplus for the under-65 population. For the purposes of quantifying the price impact of consolidations, hospitals are modeled as an input to the production of health insurance for the under-65 population. The estimates indicate that the aggregate magnitude of the impact of hospital mergers is modest but not trivial. In 2001, average HMO premiums are estimated to be 3.2% higher than they would have been absent any hospital merger activity during the 1990s. In 2003, we estimate that because of hospital mergers private insurance rolls declined by approximately .3 percentage points or approximately 695,000 lives with the vast majority of those who lost private insurance joining the ranks of the uninsured. Our estimates imply that hospital mergers resulted in a cumulative consumer surplus loss of over $42.2 billion between 1990 and 2001. It is estimated that all but a modest$95.4 million of the loss in consumer surplus is transferred from consumers to providers.