946 resultados para Control Volume, Iron Ore Direct Reduction, Composite Pellet, Axisymmetric Heat Transfer


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This layer is a georeferenced raster image of the historic paper map entitled: An accurate map of the Commonwealth of Massachusetts exclusive of the District of Maine : compiled pursuant to an act of the General Court from actual surveys of the several towns &c. taken by their order, exhibiting the boundary lines of the Commonwealth, the counties and towns, the principal roads, rivers, mountains, mines, islands, rocks, shoals, channels, lakes, ponds, falls, mills, manufactures & public buildings, with the true latitudes & longitudes, &c., by Osgood Carleton. It was published and sold by O. Carleton and I. Norman in 1795. Scale [ca. 1:281,560]. This layer is image 1 of 2 total images, representing the eastern portion of the two sheet source map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Massachusetts State Plane Coordinate System, Mainland Zone (in Feet) (Fipszone 2001). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, or other information associated with the principal map. This map shows features such as roads, bridges, academies, meeting houses, court houses, drainage, mountains, iron ore deposits, coastal navigational hazards, state, county, and town boundaries, distances of individual towns from Boston and the shire towns, and more. Relief is shown pictorially. Includes illustrative cartouche. This layer is part of a selection of digitally scanned and georeferenced historic maps of Massachusetts from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of regions, originators, ground condition dates (1755-1922), scales, and purposes. The digitized selection includes maps of: the state, Massachusetts counties, town surveys, coastal features, real property, parks, cemeteries, railroads, roads, public works projects, etc.

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This layer is a georeferenced raster image of the historic paper map entitled: An accurate map of the Commonwealth of Massachusetts exclusive of the District of Maine : compiled pursuant to an act of the General Court from actual surveys of the several towns &c. taken by their order, exhibiting the boundary lines of the Commonwealth, the counties and towns, the principal roads, rivers, mountains, mines, islands, rocks, shoals, channels, lakes, ponds, falls, mills, manufactures & public buildings, with the true latitudes & longitudes, &c., by Osgood Carleton. It was published and sold by O. Carleton and I. Norman in 1795. Scale [ca. 1:281,560]. This layer is image 2 of 2 total images, representing the western portion of the two sheet source map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Massachusetts State Plane Coordinate System, Mainland Zone (in Feet) (Fipszone 2001). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, or other information associated with the principal map. This map shows features such as roads, bridges, academies, meeting houses, court houses, drainage, mountains, iron ore deposits, coastal navigational hazards, state, county, and town boundaries, distances of individual towns from Boston and the shire towns, and more. Relief is shown pictorially. Includes illustrative cartouche. This layer is part of a selection of digitally scanned and georeferenced historic maps of Massachusetts from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of regions, originators, ground condition dates (1755-1922), scales, and purposes. The digitized selection includes maps of: the state, Massachusetts counties, town surveys, coastal features, real property, parks, cemeteries, railroads, roads, public works projects, etc.

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This layer is a georeferenced raster image of the historic paper map entitled: Map of Massachusetts proper, by Osgood Carleton ; engraved by Joseph Callender and Samuel Hill. It was published by B. & J. Loring in 1801. Scale [1:253,400]. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Massachusetts State Plane Coordinate System, Mainland Zone (in Feet) (Fipszone 2001). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, or other information associated with the principal map. This map shows features such as roads, bridges, academies, meeting houses, court houses, drainage, mountains, iron ore deposits, coastal navigational hazards, state, county, and town boundaries, distances of individual towns from Boston and the shire towns, and more. Relief is shown pictorially. Includes illustrative cartouche. This layer is part of a selection of digitally scanned and georeferenced historic maps of Massachusetts from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of regions, originators, ground condition dates (1755-1922), scales, and purposes. The digitized selection includes maps of: the state, Massachusetts counties, town surveys, coastal features, real property, parks, cemeteries, railroads, roads, public works projects, etc.

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We evaluated the role of the larval parasitoid, Diadegma semiclausum Hellen (Hymenoptera: Ichneumonidae), in controlling Plutella xylostella (L.) (Lepidoptera: Plutellidae) by cage exclusion experiments and direct field observation during the winter season in southern Queensland, Australia. The cage exclusion experiment involved uncaged, open cage and closed cage treatments. A higher percentage (54-83%) of P. xylostella larvae on sentinel plants were lost in the uncaged treatment than the closed (4-9%) or open cage treatments (11-29%). Of the larvae that remained in the uncaged treatment, 72-94% were parasitized by D. semiclausum , much higher than that in the open cage treatment (8-37% in first trial, and 38-63% in second trial). Direct observations showed a significant aggregation response of the field D. semiclausum populations to high host density plants in an experimental plot and to high host density plots that were artificially set-up near to the parasitoid source fields. The degree of aggregation varied in response to habitat quality of the parasitoid source field and scales of the manipulated host patches. As a result, density-dependence in the pattern of parasitism may depend on the relative degree of aggregation of the parasitoid population at a particular scale. A high degree of aggregation seems to be necessary to generate density-dependent parasitism by D. semiclausum . Integration of the cage exclusion experiment and direct observation demonstrated the active and dominant role of this parasitoid in controlling P. xylostella in the winter season. A biologically based IPM strategy, which incorporates the use of D. semiclausum with Bt, is suggested for the management of P. xylostella in seasons or regions with a mild temperature.

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Shvab-Zeldovich coupling of flow variables has been used to extend Van Driest's theory of turbulent boundary-layer skin friction to include injection and combustion of hydrogen in the boundary layer. The resulting theory is used to make predictions of skin friction and heat transfer that are found to be consistent with experimental and numerical results. Using the theory to extrapolate to larger downstream distances at the same experimental conditions, it is found that the reduction in skin-friction drag with hydrogen mixing and combustion is three times that with mixing alone. In application to flow on a flat plate at mainstream velocities of 2, 4, and 6 knits, and Reynolds numbers from 3 X 10(6) to 1 x 10(8), injection and combustion of hydrogen yielded values of skin-friction drag that were less than one-half of the no-injection skin-friction drag, together with a net reduction in heat transfer when the combustion heat release in air was less than the stagnation enthalpy. The mass efficiency of hydrogen injection, as measured by effective specific impulse values, was approximately 2000 s.

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Objective. To explore the relationship between measures of self-efficacy, health locus of control, health status and direct medical expenditure among community-dwelling subjects with rheumatoid arthritis (RA) and osteoarthritis (OA). Methods. This analysis is part of a larger ongoing study of the costs and outcomes of arthritis and its treatments. Community-dwelling RA and OA respondents completed questionnaires concerning arthritis-related expenditure, health status, arthritis related self-efficacy and health locus of control. Results. Data were obtained from 70 RA respondents and 223 OA respondents. The majority of respondents were female with a mean age of 63 yr for RA respondents and 68 yr for OA respondents. Among the RA respondents, those with higher self-efficacy reported better health status and lower overall costs. Health locus of control was not consistently correlated with health status. OA respondents with higher self-efficacy reported better health status and lower costs. Health locus of control had more influence. OA respondents with higher external locus of control reported worse pain and function. A higher belief in chance as a determinant of health was correlated with more visits to general practitioners and a higher cost to both the respondent and the health system. Conclusion. Higher self-efficacy, which is amenable to change through education programmes, was associated with better health status and lower costs to the respondent and the health system in this cross-sectional study. Locus of control had less of an influence; however, the tendency was for those with higher external locus of control to have higher costs and worse health status. As the measurement of these constructs is simple and the outcome potentially affects health status, these results have implications for future intervention studies to improve quality of life and reduce the financial impact of arthritis on both the health-care system and patients.

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Weathering profiles overlying the Sapecado, Pico and Andaime iron ore deposits, Quadrilátero Ferrífero (QF), Minas Gerais, Brazil, reach depths of 150–400 m and host world-class supergene iron orebodies. In addition to hosting supergene ore bodies of global economic significance, weathered banded iron-formations at the Quadrilátero Ferrífero and elsewhere (e.g., Carajás, Hamersley) are postulated to underlie some of the most ancient continuously exposed weathering profiles on earth. Laser incremental-heating 40Ar/39Ar results for 69 grains of hollandite-group manganese oxides extracted from 23 samples collected at depths ranging from 5 to 150 m at the Sapecado, Pico and Andaime deposits reveal ages ranging from ca. 62 to 14 Ma. Older Mn-oxides occur near the surface, while younger Mn-oxides occur at depth. However, many samples collected at the weathering–bedrock interface yield ages in the 51–41 Ma range, suggesting that the weathering profiles in the Quadrilátero Ferrífero had already reached their present depth in the Paleogene. The antiquity of the weathering profiles in the Quadrilátero Ferrífero is comparable to the antiquity of dated weathering profiles on banded iron-formations in the Carajás Region (Brazil) and the Hamersley Province, Western Australia. The age versus depth distributions obtained in this study, but not available for other regions containing similar supergene iron deposits, suggest that little further advance of the weathering front has occurred in the Quadrilátero Ferrífero lateritic profiles during the Neogene. The results suggest that weathering in some of these ancient landscapes is not controlled by the steady-state advance of weathering fronts through time, but may reflect climatic and geomorphological conditions prevailing in a remote past. The geochronological results also confirm that the ancient landsurfaces in the Quadrilátero Ferrífero probably remained immune to erosion for tens of millions of years. Deep weathering, mostly in the Paleogene, combined with low erosion rates, account for the abundance and widespread distribution of supergene iron, manganese, and aluminum orebodies in this region.

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In the last few decades, the world has witnessed an enormous growth in the volume of foreign direct investment (FDI). The global stock of FDI reached US$ 7.5 trillion in 2003 and accounted for 11% of world Gross Domestic Product, up from 7% in 1990. The sales of multinational enterprises at around US$ 19 trillion were more than double the level of world exports. Substantial FDI inflows went into transition countries. Inflows into one of the region's largest recipient, the Russian Federation, almost doubled, enabling Russia to become one of the five top FDI destinations in 2005-2006. FDI inflows in Russia have increased almost threefold from 13.6% in 2003 to 35% in 2007. In 2003, these flows were twice greater than those into China; whilst in 2007 they were six times larger. Russia's FDI inflows were also about 2.5 times greater than those of Brazil. Efficient government institutions are argued by many economists to foster FDI and growth as a result. However, the magnitude of this effect has yet to be measured. This thesis takes a Political Economy approach to explore, empirically, the potential impact of malfunctioning governmental institutions, proxied by three indices of perceived corruption, on FDI stocks accumulation/distribution within Russia over the period of 2002-2004. Using a regional data-set it concentrates on three areas relating to FDI. Firstly, it considers the significance, the size and the sign of the impact of perceived corruption on accumulation of FDI stocks within Russia. Secondly, it quantifies the impact of perceived corruption on the volume of FDI stocks simultaneously estimating the impact of the investment in public capital such as telecommunications and transportation networks on FDI in the presence of corruption. In particular, it addresses the question whether more corrupt regions in Russia are also those that could have accumulated more of FDI stocks, and investigates whether those 'more corrupt' regions would have had lower level of public capital investment. Finally, it examines whether decentralisation increases or decreases corruption and whether a larger extent of decentralisation has a positive or negative impact on FDI (stocks). The results of three studies are as follows. Firstly, along with market potential, corruption is found to be one of the key factors in explaining FDI distribution within Russia between 2002 and 2004. Secondly, corruption on average is found to be related to FDI positively suggesting that it may act as speed money: to save their time foreign direct investors might be willing to bribe the regional authorities so to move in front of the bureaucratic lines. Thirdly, although when corruption is controlled for, the impact of the latter on unobservable FDI is found to be on average positive, no association between FDI and public investment is observed with the only exception of transportation infrastructure (i.e., railway). The results might suggest therefore that it is possible that not only regions with high levels of perceived corruption attract more FDI but also that expansions in public capital investments are not accompanied by an increase of the volume of FDI (stocks) in regions with high levels of corruption. This casts some doubt on the productivity of the investment in public capital in these regions as it might be that bureaucrats may prefer to use these infrastructural projects for rent extraction. Finally, we find decentralisation to have a significant and positive impact on both FDI stock accumulation and corruption, suggesting that local governments may spend more on public goods to make the area more attractive to foreign investors but at the same time they may be interested into extracting rents from foreign investors. These results support the idea that the regulation of FDI is associated with and facilitated by a larger public sector, which distorts competition and introduces opportunities for rent-seeking by particular economic and political factors.

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This thesis describes an investigation of methods by which both repetitive and non-repetitive electrical transients in an HVDC converter station may be controlled for minimum overall cost. Several methods of inrush control are proposed and studied. The preferred method, whose development is reported in this thesis, would utilize two magnetic materials, one of which is assumed to be lossless and the other has controlled eddy-current losses. Mathematical studies are performed to assess the optimum characteristics of these materials, such that inrush current is suitably controlled for a minimum saturation flux requirement. Subsequent evaluation of the cost of hardware and capitalized losses of the proposed inrush control, indicate that a cost reduction of approximately 50% is achieved, in comparison with the inrush control hardware for the Sellindge converter station. Further mathematical studies are carried out to prove the adequacy of the proposed inrush control characteristics for controlling voltage and current transients during both repetitive and non-repetitive operating conditions. The results of these proving studies indicate that no change in the proposed characteristics is required to ensure that integrity of the thyristors is maintained.

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We completed a synoptic survey of iron, phosphorus, and sulfur concentrations in shallow marine carbonate sediments from south Florida. Total extracted iron concentrations typically were 50 μmol g-1 dry weight (DW) and tended to decrease away from the Florida mainland, whereas total extracted phosphorus concentrations mostly were 10 μmol g-1 DW and tended to decrease from west to east across Florida Bay. Concentrations of reduced sulfur compounds, up to 40 μmol g-1 DW, tended to covary with sediment iron concentrations, suggesting that sulfide mineral formation was iron-limited. An index of iron availability derived from sediment data was negatively correlated with chlorophyll a concentrations in surface waters, demonstrating the close coupling of sediment-water column processes. Eight months after applying a surface layer of iron oxide granules to experimental plots, sediment iron, phosphorus, and sulfur were elevated to a depth of 10 cm relative to control plots. Biomass of the seagrass Thalassia testudinum was not different between control and iron addition plots, but individual shoot growth rates were significantly higher in experimental plots after 8 months. Although the iron content of leaf tissues was significantly higher from iron addition plots, no difference in phosphorus content of T. testudinum leaves was observed. Iron addition altered plant exposure to free sulfide, documented by a significantly higher δ34S of leaf tissue from experimental plots relative to controls. Iron as a buffer to toxic sulfides may promote individual shoot growth, but phosphorus availability to plants still appears to limit production in carbonate sediments.

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A uniform chronology for foraminifera-based sea surface temperature records has been established in more than 120 sediment cores obtained from the equatorial and eastern Atlantic up to the Arctic Ocean. The chronostratigraphy of the last 30,000 years is mainly based on published d18O records and 14C ages from accelerator mass spectrometry, converted into calendar-year ages. The high-precision age control provides the database necessary for the uniform reconstruction of the climate interval of the Last Glacial Maximum within the GLAMAP-2000 project.