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Artykuły w czasopismach na temat "Dry Valleys Region"
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Witherow, Rebecca A., W. Berry Lyons, Nancy A. N. Bertler, Kathleen A. Welch, Paul A. Mayewski, Sharon B. Sneed, Thomas Nylen, Michael J. Handley i Andrew Fountain. "The aeolian flux of calcium, chloride and nitrate to the McMurdo Dry Valleys landscape: evidence from snow pit analysis". Antarctic Science 18, nr 4 (14.11.2006): 497–505. http://dx.doi.org/10.1017/s095410200600054x.
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We have determined the flux of calcium, chloride and nitrate to the McMurdo Dry Valleys region by analysing snow pits for their chemical composition and their snow accumulation using multiple records spanning up to 48 years. The fluxes demonstrate patterns related to elevation and proximity to the ocean. In general, there is a strong relationship between the nitrate flux and snow accumulation, indicating that precipitation rates may have a great influence over the nitrogen concentrations in the soils of the valleys. Aeolian dust transport plays an important role in the deposition of some elements (e.g. Ca2+) into the McMurdo Dry Valleys' soils. Because of the antiquity of some of the soil surfaces in the McMurdo Dry Valleys regions, the accumulated atmospheric flux of salts to the soils has important ecological consequences. Although precipitation may be an important mechanism of salt deposition to the McMurdo Dry Valley surfaces, it is poorly understood because of difficulties in measurement and high losses from sublimation.
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Smillie, Robert W. "Suite subdivision and petrological evolution of granitoids from the Taylor Valley and Ferrar Glacier region, south Victoria Land". Antarctic Science 4, nr 1 (marzec 1992): 71–87. http://dx.doi.org/10.1017/s0954102092000130.
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Detailed geological mapping and geochemical analysis of early Palaeozoic granitoid plutons and dykes from the Taylor Valley and Ferrar Glacier region in south Victoria Land reveal two distinct suites. This suite subdivision-approach is a departure from previous lithology-based schemes and can be applied elsewhere in south Victoria Land. The older calc-alkaline Dry Valleys 1 suite is dominated by the compositionally variable Bonney Pluton, a flow-foliated concordant pluton with an inferred length of over 100 km. Plutons of this suite are elongate in a NW-SE direction and appear to have been subjected to major structural control during their emplacement. The younger alkali-calcic Dry Valleys 2 suite comprises discordant plutons and numerous dyke swarms with complex age relationships. Field characteristics of this suite indicate that it was passively emplaced into fractures at higher levels in the crust than the Dry Valleys 1 suite. Whole-rock geochemistry confirms this suite subdivision based on field relationships and indicates that the two suites were derived from different parent magmas by fractional crystallization. The Dry Valleys 1 suite resembles Cordilleran I-type granitoids and is inferred to be derived from partial melting of the upper mantle and/or lower crust above an ancient subduction zone. The Dry Valleys 2 suite resembles Caledonian I-type granitoids and may have resulted from a later episode of crustal extension.
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Hall, B. L., G. H. Denton i B. Overturf. "Glacial Lake Wright, a high-level Antarctic lake during the LGM and early Holocene". Antarctic Science 13, nr 1 (marzec 2001): 53–60. http://dx.doi.org/10.1017/s0954102001000086.
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We report evidence of a large proglacial lake (Glacial Lake Wright) that existed in Wright Valley in the McMurdo Dry Valleys region of Antarctica at the last glacial maximum (LGM) and in the early Holocene. At its highstands, Glacial Lake Wright would have stretched 50 km and covered c. 210 km2. Chronology for lake-level changes comes from 30 AMS radiocarbon dates of lacustrine algae preserved in deltas, shorelines, and glaciolacustrine deposits that extend up to 480 m above present-day lakes. Emerging evidence suggests that Glacial Lake Wright was only one of a series of large lakes to occupy the McMurdo Dry Valleys and the valleys fronting the Royal Society Range at the LGM. Although the cause of such high lake levels is not well understood, it is believed to relate to cool, dry conditions which produced fewer clouds, less snowfall, and greater amounts of absorbed radiation, leading to increased meltwater production.
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Tang, Ya, Jiasui Xie i Hui Sun. "Revisiting sustainable development of dry valleys in Hengduan Mountains Region". Journal of Mountain Science 1, nr 1 (luty 2004): 38–45. http://dx.doi.org/10.1007/bf02919358.
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Esposito, R. M. M., S. A. Spaulding, D. M. McKnight, B. Van de Vijver, K. Kopalová, D. Lubinski, B. Hall i T. Whittaker. "Inland diatoms from the McMurdo Dry Valleys and James Ross Island, Antarctica". Botany 86, nr 12 (grudzień 2008): 1378–92. http://dx.doi.org/10.1139/b08-100.
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Diatom taxa present in the inland streams and lakes of the McMurdo Dry Valleys and James Ross Island, Antarctica, are presented in this paper. A total of nine taxa are illustrated, with descriptions of four new species ( Luticola austroatlantica sp. nov., Luticola dolia sp. nov., Luticola laeta sp. nov., Muelleria supra sp. nov.). In the perennially ice-covered lakes of the McMurdo Dry Valleys, diatoms are confined to benthic mats within the photic zone. In streams, diatoms are attached to benthic surfaces and within the microbial mat matrix. One species, L. austroatlantica, is found on James Ross Island, of the southern Atlantic archipelago, and the McMurdo Dry Valleys. The McMurdo Dry Valley populations are at the lower range of the size spectrum for the species. Streams flow for 6–10 weeks during the austral summer, when temperatures and solar radiation allow glacial ice to melt. The diatom flora of the region is characterized by species assemblages favored under harsh conditions, with naviculoid taxa as the dominant group and several major diatom groups conspicuously absent.
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Cox, Simon C., i Andrew H. Allibone. "Petrogenesis of orthogneisses in the Dry Valleys region, South Victoria Land". Antarctic Science 3, nr 4 (grudzień 1991): 405–17. http://dx.doi.org/10.1017/s0954102091000500.
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Granitoid gneisses intercalated with Koettlitz Group metasediments in the upper Ferrar, Taylor and Wright valleys of South Victoria Land comprise various hornblende+biotite orthogneisses and biotite orthogneisses, including the km-scale Dun and Calkin plutons. K-feldspar megacryst inclusion textures and discordant cross-cutting relationships with enclosing metasediments are interpreted as firm evidence of an intrusive origin for hornblende+biotite and biotite orthogneiss. The scale of several concordant orthogneiss bodies (including the Dun and Calkin plutons), the presence of mafic enclaves, and relict flow differentiation in hornblende+biotite orthogneiss are also compatible with a plutonic origin. Orthogneisses were emplaced prior to deformation that produced macroscopic upright, tight, folds about NW-trending axes. Petrography and geochemistry indicate I-type affinities for hornblende+biotite orthogneisses and the Dun Pluton. Hornblende+biotite and biotite orthogneisses (with the exception of the Dun Pluton) are part of a single petrogenetic suite, together with younger Bonney, Valhalla, and Hedley plutons. Emplacement of a continuum of I-type intrusives is envisaged which spanned Koettlitz Group deformation, and possibly caused much of the deformation. Hornblende+biotite and biotite orthogneisses are deformed precursors to the younger Bonney, Valhalla, and Hedley plutons. The Dun Pluton contains Fe-rich salitic clinopyroxene relicts and exhibits a unique geochemistry. It is rich in Sr, Al2O3, Na2O, and poor in FeO, K2O, Rb, Y, V. Chemical and petrographic features indicate an evolved body, possibly derived from a primitive source distinct from other orthogneisses and granitoids.
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Ukrainskiy, Pavel, Edgar Terekhin, Artyom Gusarov, Eugenia Zelenskaya i Fedor Lisetskii. "The Influence of Relief on the Density of Light-Forest Trees within the Small-Dry-Valley Network of Uplands in the Forest-Steppe Zone of Eastern Europe". Geosciences 10, nr 11 (24.10.2020): 420. http://dx.doi.org/10.3390/geosciences10110420.
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An active process of the invasion of woody vegetation, resulting in the formation of light forests, has been observed in predominantly herbaceous small dry valleys of the forest-steppe uplands of the East European Plain over the past two decades. This paper investigates the spatial features of the density of trees in such light forests and its relationship with relief parameters. The Belgorod Region, one of the administrative regions of European Russia, was chosen as a reference for the forest-steppe zone of the plain. The correlation between some relief characteristics (the height, slope, slope exposure cosine, topographic position index, morphometric protection index, terrain ruggedness index, and width and depth of small dry valleys) and the density of light-forest trees was estimated. The assessment was carried out at the local, subregional and regional levels of generalization. The relief influence on the density of trees in the small dry valley network is manifested both through the differentiation of moisture within the territory under study and the formation of various conditions for fixing tree seedlings in the soil. This influence on subregional and regional trends in the density is greater than on local trends. The results obtained are important for the management of herbaceous small-dry-valley ecosystems within the forest-steppe uplands in Eastern Europe.
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Mellon, Michael T., Christopher P. Mckay i Jennifer L. Heldmann. "Polygonal ground in the McMurdo Dry Valleys of Antarctica and its relationship to ice-table depth and the recent Antarctic climate history". Antarctic Science 26, nr 4 (26.11.2013): 413–26. http://dx.doi.org/10.1017/s0954102013000710.
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AbstractThe occurrence of dry permafrost overlying ice-rich permafrost is unique to the Antarctic Dry Valleys on Earth and to the high latitudes of Mars. The stability and distribution of this ice are poorly understood and fundamental to understanding the Antarctic climate as far back as a few million years. Polygonal patterned ground is nearly ubiquitous in these regions and is integrally linked to the history of the icy permafrost and climate. We examined the morphology of polygonal ground in Beacon Valley and the Beacon Heights region of the Antarctic Dry Valleys, and show that polygon size is correlated with ice-table depth (the boundary between dry and ice-rich permafrost). A numerical model of seasonal stress in permafrost shows that the ice-table depth is a dominant factor. Remote sensing and field observations of polygon size are therefore important tools for investigating subsurface ice. Polygons are long-lived landforms and observed characteristics indicate no major fluctuations in the ice-table depth during their development. We conclude that the Beacon Valley and Beacon Heights polygons have developed for at least 104 years to achieve their present mature-stage morphology and that the ice-table depth has been stable for a similar length of time.
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Clausen, Eric. "Origin of the Redwater River Drainage Basin Determined by Topographic Map Interpretation: Eastern Montana, USA". Journal of Geography and Geology 11, nr 1 (26.02.2019): 42. http://dx.doi.org/10.5539/jgg.v11n1p42.
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Topographic and geologic map interpretation strongly suggests the eastern Montana Redwater River valley eroded headward across large southeast-oriented ice-marginal melt water floods. The north-oriented Redwater River heads in an area to the south of recognized continental glaciation and flows into the recognized glaciated region before joining the east-oriented Missouri River. Detailed topographic maps show the eastern drainage divide is asymmetric with steeper slopes on the Redwater River side and is crossed by shallow dry valleys linking northwest-oriented Redwater River tributaries with southeast-oriented streams that flow as barbed tributaries to the northeast-oriented Yellowstone River. The western drainage divide is also crossed by shallow dry valleys linking northwest-oriented drainage routes to north-oriented Missouri River tributaries with southeast-oriented and barbed tributaries to the northeast- and north-oriented Redwater River. Alluvium from upstream Yellowstone River source areas found within the Redwater River drainage basin suggests the Redwater River and much longer Yellowstone River valleys eroded headward from a continental ice sheet margin as headward erosion of the larger Yellowstone River valley across the southeast-oriented flood flow was supplemented by northeast- and north-oriented flow moving at the present day Redwater-Yellowstone River drainage divide elevation.
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Lyons, W. B., S. W. Tyler, R. A. Wharton, D. M. McKnight i B. H. Vaughn. "A Late Holocene desiccation of Lake Hoare and Lake Fryxell, McMurdo Dry Valleys, Antarctica". Antarctic Science 10, nr 3 (wrzesień 1998): 247–56. http://dx.doi.org/10.1017/s0954102098000340.
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Stable isotope data from waters of lakes in the McMurdo Dry Valleys (MDV) of southern Victoria Land, Antarctica are presented in order to establish the climatic history of this region over the past two millennia. New data from Lake Fryxell and Lake Hoare in Toylor Valley, along with previously published data from Lake Vanda, Wright Valley and Lake Bonney, Taylor Valley are used to infer the recent climatic history of MDV. Lakes Vanda, Fryxell and Bonney appear to have lost their ice covers and evaporated to small, hypersaline ponds by 1000 to ~1200 yr BP. Lake Hoare either desiccated or did not exist prior to 1200 yr BP. These data indicate a major lowering of lake level prior to ~1000 yr BP, followed by a warmer and/or more humid climate since then.
Rozprawy doktorskie na temat "Dry Valleys Region"
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Peebles, Michael J., i William G. Jr Robertson. "Video Repeater for the Dry Valleys Region of Antarctica". International Foundation for Telemetering, 1993. http://hdl.handle.net/10150/611881.
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International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, NevadaA repeater is being designed to provide a telemetry and compressed video link from a remote robot located in the Dry Valleys Region of Antarctica, over a mountain range to California via McMurdo Antarctica. In return a command link is provided for control. A simple task normally, but a bit more difficult when considerations include the unforgiving elements of Antarctica itself. Even with a design using the most robust equipment, tradeoffs must always be made for the effects of the isolation and the weather. This paper describes one approach to the design of equipment capable of insuring the proper bandwidth, power output, and receive sensitivity that can use the energy provided by Mother Nature to continually charge the primary power source, and the engineering struggle to use electronic equipment in the severe and harsh environment of Antarctica.
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Sirota, Paul, i n/a. "The effects of solutes, debris and temperature on the shear strength of basal ice in cold-based glaciers". University of Otago. Department of Geography, 2008. http://adt.otago.ac.nz./public/adt-NZDU20081204.142406.
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Isotropic ice samples containing measured concentrations of solutes and debris similar to basal material found in several cold-based glaciers in the McMurdo Dry Valleys, Antarctica, were manufactured in a laboratory and tested for peak shear strength at constant strain rates with a direct-shear device. The shear tests show that differences in rheology and shear strength appear to be related to impurity content and concentration. Debris-laden ice becomes more ductile with greater concentrations of solutes, whereas, low solute-concentrations and high debris-concentrations are associated with increases in shear strength and brittle behaviour. Stress exponents from Glen�s flow law calculated for isotropic solute and debris-laden ice ranged between 4 and 5, leading to the conclusion that higher rates of deformation may be expected in dirty basal ice than predicted for glacial ice models that use stress exponents where, n = 3. Observations of both natural and synthetic samples tested over a range of temperatures between -25�C and -5�C showed that natural basal ice samples containing high solute and debris concentrations were highly sensitive to temperature change. These tests showed an approximate 10 % loss in shear strength for every 1�C increase in temperature between -25�C and -10�C. In addition, contrasts in rheology and rates of deformation within basal ice are responsible for the development of debris-laden ice structures in the basal zones of cold-based glaciers that flow over unconsolidated substrates. As layered sedimentary bedding was preserved in frozen blocks within the deforming basal ice of several of these glaciers, the evidence suggests that at some point each glacier has interacted with its bed and entrained portions of the substrate material. Empirical shear strength data and observations of rheological changes attributed to composition together with evidence acquired during fieldwork in Antarctica help to support the argument that cold-based glaciers flowing over unconsolidated sediment are capable of affecting geomorphic change. Hence, isotropic ice models that exclude basal processes may need to be adjusted, especially where small increases in the temperature of the basal zones of cold glaciers may occur. In conclusion, palaeo-climate inferences based purely upon small amounts of geomorphic evidence, which suggest warmer climate conditions, may need to be re-evaluated in order to portray more accurate renditions of formerly glaciated landscapes.
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Marchant, David R. "Miocene-Pliocene-Pleistocene paleoclimate and glacial history of the western Dry Valleys region, Antarctica". Thesis, University of Edinburgh, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538081.
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A case is made for the stability of the polar East Antarctic Ice Sheet since middle-Miocene time from landscape development and surficial sediments in the western Dry Valleys region, southern Victoria Land. The alternate hypothesis that calls for repeated Miocene and Pliocene growth and decay of wet-based ice sheets across East Antarctica requires atmospheric temperatures 20"C above present values and late Pliocene ice-sheet overriding of the Transantarctic Mountains. The geomorphological and sedimentological results suggest that these conditions were not met in the western Dry Valleys. Rather, mean annual atmospheric temperatures during the last 13.6 Ma were at most only 3° to SoC above present values; ice-sheet overriding occurred in middle Miocene time (> 13.6 Ma); and Pliocene glacier expansion was limited. These conclusions are based on field studies in the western Asgard Range and in the Quartermain Mountains. The chronology comes from 4OAr/39 Ar laser fusion analyses on individual volcanic crystals and glass shards removed from in-situ volcanic ashes that occur in stratigraphic association with unconsolidated diamictons in the western Dry Valleys region. The combined geomorphological and sedimentological evidence indicates that slope evolution in the western Dry Valleys was severely restricted since at least the middle Miocene. The implication is that most of the landscape is relict and that it reflects ancient erosion under semi-arid climate conditions prior to middle-Miocene time.
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Kuiper, John R. "The Role of Rainfed Farm Ponds in Sustaining Agriculture and Soil Conservation in the Dry High Valley Region of Cochabamba, Bolivia: Design Considerations and Post Impoundment Analysis". Thesis, University of North Texas, 1999. https://digital.library.unt.edu/ark:/67531/metadc501015/.
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Lack of sufficient water for irrigation is a major problem in and around the valleys surrounding the town of Aiquile, Cochabamba Bolivia. In addition, much of the region is undergoing desertification compounded by drought, deforestation, bad traditional agricultural practices, over grazing and a "torrential" rainfall pattern leading to severe soil erosion and low agricultural production. Between 1992 and 1994, the author constructed a network of 24 small, mostly rainfed farm ponds to increase agricultural production and alleviate soil erosion and land-use problems by improving cover conditions. A 5-year post-impoundment analysis was carried out in 1998. The analysis examined current pond conditions, design criteria, irrigation water / crop production increases and the alleviation of land-use problems. Current pond conditions fell into four distinct categories with only 25 percent of the ponds being deemed as "functioning well." The project increased irrigation in the region and improved cover conditions in 66 percent of the pond sites.
Książki na temat "Dry Valleys Region"
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Hollingshead, Anne. Day hiking near Sun Valley: With wildflower lists for nearby mountain regions. Ketchum, ID: Idaho Conservation League, 1995.
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Hollingshead, Anne. Day hiking near Sun Valley: With wildflower lists for nearby mountain regions. Sun Valley, Idaho: Gentian Press, 1987.
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Noyalas, Jonathan A. Slavery and Freedom in the Shenandoah Valley during the Civil War Era. University Press of Florida, 2021. http://dx.doi.org/10.5744/florida/9780813066868.001.0001.
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In Slavery and Freedom in the Shenandoah Valley during the Civil War Era, Jonathan Noyalas examines the complexities of life for African Americans in Virginia’s Shenandoah Valley from the antebellum period through Reconstruction. Although the Valley was a site of fierce conflicts during the Civil War and its military activity has been extensively studied, scholars have largely ignored the black experience in the region until now. Correcting previous assumptions that slavery was not important to the Valley, and that enslaved people were treated better there than in other parts of the South, Jonathan Noyalas demonstrates the strong hold of slavery in the region. He explains that during the war, enslaved and free African Americans navigated a borderland that changed hands frequently—where it was possible to be in Union territory one day, Confederate territory the next, and no-man’s land another. He shows that the region’s enslaved population resisted slavery and supported the Union war effort by serving as scouts, spies, and laborers, or by fleeing to enlist in regiments of the United States Colored Troops. Noyalas draws on untapped primary resources, including thousands of records from the Freedmen’s Bureau and contemporary newspapers, to continue the story and reveal the challenges African Americans faced from former Confederates after the war. He traces their actions, which were shaped uniquely by the volatility of the struggle in this region, to ensure that the war’s emancipationist legacy would survive.
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Laneri, Nicola, i Mark Schwartz. Southeastern and Eastern Anatolia in the Middle Bronze Age. Redaktorzy Gregory McMahon i Sharon Steadman. Oxford University Press, 2012. http://dx.doi.org/10.1093/oxfordhb/9780195376142.013.0014.
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This article presents data on the Middle Bronze Age (MBA) of southeastern and eastern Anatolia, which were more resilient than northern Mesopotamia and never endured the collapse suffered there at the end of the third millennium BCE. On the contrary, the mixed subsistence economy and the relatively lower levels of urbanism and reliance on intensive dry farming made these Anatolian societies more resilient and less prone to ecological disaster. Thus, the climatic catastrophe that devastated numerous urban centers of northern Mesopotamia did not affect the Anatolian regions, which instead show clear signs of continuity between the Early and the Middle Bronze Age periods. In addition, interregional exchange between these regions and northern Mesopotamia played an important part in the further development of these communities during the MBA and in creating the framework for the creation of important city-states, especially along the Upper Euphrates River Valley, and for strengthening local networks of chiefly estates, primarily in the Upper Tigris region.
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Hansen, Christine, i Tom Griffiths. Living with Fire. CSIRO Publishing, 2012. http://dx.doi.org/10.1071/9780643104808.
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Within the Yarra River catchment area nestles the valley of Steels Creek, a small shallow basin in the lee of Kinglake plateau and the Great Dividing Range. The escarpment walls of the range drop in a series of ridges to the valley and form the south-eastern boundary of the Kinglake National Park. The gentle undulations that flow out from the valley stretch into the productive and picturesque landscape of Victoria’s famous wine growing district, the Yarra Valley.
Late on the afternoon of 7 February 2009, the day that came to be known as Black Saturday, the Kinglake plateau carried a massive conflagration down the fringing ranges into the Steels Creek community. Ten people perished and 67 dwellings were razed in the firestorm. In the wake of the fires, the devastated residents of the valley began the long task of grieving, repairing, rebuilding or moving on while redefining themselves and their community.
In Living with Fire, historians Tom Griffiths and Christine Hansen trace both the history of fire in the region and the human history of the Steels Creek valley in a series of essays which examine the relationship between people and place. These essays are interspersed with four interludes compiled from material produced by the community. In the immediate aftermath of the fire many people sought to express their grief, shock, sadness and relief in artwork. Some painted or wrote poetry, while others collected the burnt remains of past treasures from which they made new objects. These expressions, supplemented by historical archives and the essays they stand beside, offer a sensory and holistic window into the community’s contemporary and historical experiences.
A deeply moving book, Living with Fire brings to life the stories of one community’s experience with fire, offering a way to understand the past, and in doing so, prepare for the future.
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Tevis, Yvonne P. The Coachella Valley Preserve: The Struggle for a Desert Wetlands (Great Issues of the Day, No. 5). Borgo Press, 1995.
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Dyson, Tim. A Population History of India. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198829058.001.0001.
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This book provides an account of the size and characteristics of India’s population stretching from the arrival of modern human beings until the present day. The periods considered include those of: the millennia that were occupied by hunting and gathering; the Indus valley civilization; the opening-up of the Ganges basin; and the eras of the Delhi Sultanate, Mughal Empire, and British colonial rule. The book also devotes substantial consideration to the unprecedented changes that have occurred in India since 1947. With reference to these and other periods, key topics addressed include: the scale of the population; the levels of mortality and fertility that prevailed; regional demographic variation; the size of the main cities; the level of urbanization; patterns of migration; and the many famines, epidemics, invasions and other events which affected the population. The book is a work of synthesis—albeit one with few certainties. It draws on research of many different kinds—e.g. archaeological, climatic, cultural, economic, epidemiological, historical, linguistic, political, and demographic. The book considers the past trajectory of India’s population compared to the trends which seem to have been shared by China and Europe. In addition, it highlights some misconceptions about the history of India’s population.
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Verschuur, Gerrit L. Impact! Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195101058.001.0001.
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Most scientists now agree that some sixty-five million years ago, an immense comet slammed into the Yucatan, detonating a blast twenty million times more powerful than the largest hydrogen bomb, punching a hole ten miles deep in the earth. Trillions of tons of rock were vaporized and launched into the atmosphere. For a thousand miles in all directions, vegetation burst into flames. There were tremendous blast waves, searing winds, showers of molten matter from the sky, earthquakes, and a terrible darkness that cut out sunlight for a year, enveloping the planet in freezing cold. Thousands of species of plants and animals were obliterated, including the dinosaurs, some of which may have become extinct in a matter of hours. In Impact, Gerrit L. Verschuur offers an eye-opening look at such catastrophic collisions with our planet. Perhaps more important, he paints an unsettling portrait of the possibility of new collisions with earth, exploring potential threats to our planet and describing what scientists are doing right now to prepare for this awful possibility. Every day something from space hits our planet, Verschuur reveals. In fact, about 10,000 tons of space debris fall to earth every year, mostly in meteoric form. The author recounts spectacular recent sightings, such as over Allende, Mexico, in 1969, when a fireball showered the region with four tons of fragments, and the twenty-six pound meteor that went through the trunk of a red Chevy Malibu in Peekskill, New York, in 1992 (the meteor was subsequently sold for $69,000 and the car itself fetched $10,000). But meteors are not the greatest threat to life on earth, the author points out. The major threats are asteroids and comets. The reader discovers that astronomers have located some 350 NEAs ("Near Earth Asteroids"), objects whose orbits cross the orbit of the earth, the largest of which are 1627 Ivar (6 kilometers wide) and 1580 Betula (8 kilometers). Indeed, we learn that in 1989, a bus-sized asteroid called Asclepius missed our planet by 650,000 kilometers (a mere six hours), and that in 1994 a sixty-foot object passed within 180,000 kilometers, half the distance to the moon. Comets, of course, are even more deadly. Verschuur provides a gripping description of the small comet that exploded in the atmosphere above the Tunguska River valley in Siberia, in 1908, in a blinding flash visible for several thousand miles (every tree within sixty miles of ground zero was flattened). He discusses Comet Swift-Tuttle--"the most dangerous object in the solar system"--a comet far larger than the one that killed off the dinosaurs, due to pass through earth's orbit in the year 2126. And he recounts the collision of Comet Shoemaker-Levy 9 with Jupiter in 1994, as some twenty cometary fragments struck the giant planet over the course of several days, casting titanic plumes out into space (when Fragment G hit, it outshone the planet on the infrared band, and left a dark area at the impact site larger than the Great Red Spot). In addition, the author describes the efforts of Spacewatch and other groups to locate NEAs, and evaluates the idea that comet and asteroid impacts have been an underrated factor in the evolution of life on earth. Astronomer Herbert Howe observed in 1897: "While there are not definite data to reason from, it is believed that an encounter with the nucleus of one of the largest comets is not to be desired." As Verschuur shows in Impact, we now have substantial data with which to support Howe's tongue-in-cheek remark. Whether discussing monumental tsunamis or the innumerable comets in the Solar System, this book will enthrall anyone curious about outer space, remarkable natural phenomenon, or the future of the planet earth.
Części książek na temat "Dry Valleys Region"
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Qinye, Yang. "Dry Valleys in Hengduan Mts Region". W Mountain Geoecology and Sustainable Development of the Tibetan Plateau, 283–302. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-010-0965-2_14.
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Curtis, Garniss H., i Clyde Wahrhaftig. "Trip log day 5 (July 5, 1989): Monticello Dam-Napa Valley". W Geology of San Francisco and Vicinity: San Francisco Bay Region, California: July 1–7, 1989, 54–56. Washington, D. C.: American Geophysical Union, 1989. http://dx.doi.org/10.1029/ft105p0054.
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Alexander, Earl B., Roger G. Coleman, Todd Keeler-Wolfe i Susan P. Harrison. "Southern California Coast Ranges, Domain 3". W Serpentine Geoecology of Western North America. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780195165081.003.0021.
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The Southern California Coast Range domain is a mountainous region with subparallel ridges aligned north–south, or more precisely north, northwest–south, southeast, and with intervening valleys that are controlled by strike-slip faulting. It extends about 400 km from the Golden Gate at the entrance to San Francisco Bay south to the Transverse Ranges that have east–west trending ridges. The domain corresponds to a physiographic region about 400 km long and 100 km wide that is bound by the Pacific Ocean on the west, the Great Valley of California on the east, on the north by the drainage outlet of the Sacramento and San Joaquin Rivers through the Carquinas Straight and San Pablo Bay, and on the south by the Transverse Ranges. Ridges in the Southern California Coast Ranges generally have nearly level crests (Page et al. 1997), but they range considerably in height up to about 1500 m on some of the higher peaks. No streams from the Great Valley cross the Southern California Coast Ranges to the Ocean; the Great Valley drains through the Carquinez Straight and Golden Gate at the north end of these ranges. The larger streams in the Southern California Coast Ranges drain from the Santa Clara Valley, Salinas Valley, and Cuyama Valley to the San Francisco, Monterey, and San Luis Obispo bays. Only relatively small streams drain to the Great Valley, but some of them have large alluvial fans in the valley. There are many Tertiary-faultbound valleys and basins among the mountain ranges. Some of the more prominent basins are the Santa Maria basin, Carrizo Plains, Paso Robles basin, and Watsonville basin. Serpentine is scattered in relatively small bodies throughout the domain and is concentrated along some of the major faults and in the New Idria area (locality 3-12). Climates range from cool and foggy along the coast to warm inland, with hot and dry summers inland from the fog belt.
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Welch, Kathleen A., i W. Berry Lyons. "Climate and Hydrologic Variations and Implications for Lake and Stream Ecological Response in the McMurdo Dry Valleys, Antarctica". W Climate Variability and Ecosystem Response in Long-Term Ecological Research Sites. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195150599.003.0019.
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Because polar regions may amplify what would be considered small to moderate climate changes at lower latitudes, Weller (1998) proposed that the monitoring of high latitude regions should yield early evidence of global climate change. In addition to the climate changes themselves, the connections between the polar regions and the lower latitudes have recently become of great interest to meteorologists and paleoclimatologists alike. In the southern polar regions, the direct monitoring of important climatic variables has taken place only for the last few decades, largely because of their remoteness. This of course limits the extent to which polar records can be related to low latitude records, even at multiyear to decadal timescales. Climatologists and ecologists are faced with the problem that, even though these high latitude regions may provide important clues to global climatic change, the lengths of available records are relatively short. The McMurdo Dry Valleys Long-Term Ecological Research (MCM LTER) program was established in 1993. This program built on the monitoring begun in the late 1960s by researchers from New Zealand, who collected records of climate, lake level, and stream discharge in the Wright Valley, Antarctica. Griffith Taylor’s field party obtained the first data related to lake level in 1903 as part of Scott’s Discovery expedition. Analysis of the more recent data from the New Zealand Antarctic and MCM LTER programs when compared to the 1903 datum indicates that the first half of the twentieth century was a period of steadily increasing streamflows, followed in the last half of the century by streamflows that have resulted in more slowly increasing or stable lake levels (Bomblies et al. 2001). Thus, meteorological and hydrological records generated by the MCM LTER research team, when coupled with past data and the ecological information currently being obtained, provide the first detailed attempt to understand the connection between ecosystem structure and function and climatic change in this region of Antarctica. In addition, the program helps to fill an important gap in the overall understanding of climatic variability in Antarctica.
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Barker, Graeme. "Central and South Asia: theWheat/Rice Frontier". W The Agricultural Revolution in Prehistory. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780199281091.003.0010.
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This chapter intentionally overlaps with Chapter 4 in its geographical scope, as there is no clear boundary between South-West and South Asia. Western Asiatic landforms—mountain ranges, alluvial valleys, semi-arid steppe, and desert—extend eastwards from the Iranian plateau beyond the Caspian Sea into Turkmenistan in Central Asia, and there are similar environments in South Asia from Baluchistan (western Pakistan) and the Indus valley into north-west India as far east as the Aravalli hills (Fig. 5.1). Rainfall increases steadily moving eastwards across the vast and immensely fertile alluvial plains of northern India. The north-east (Bengal, Assam, Bhutan) is tropical, with tropical conditions also extending down the eastern coast of the peninsula and up the west coast as far as Bombay. Today the great majority of the rural population of the region lives by agriculture, though many farmers also hunt game if they have the opportunity. The ‘Eurasian’ farming system predominates in the western part of the region: the cultivation of crops sown in the winter and harvested in the spring (rabi), such as barley, wheat, oats, lentils, chickpeas, jujube, mustard, and grass peas, integrated with animal husbandry based especially on sheep, goats, and cattle. A second system (kharif ) takes advantage of the summer monsoon rains: crops are sown in the late spring at the start of the monsoon and harvested in the autumn. Rice (Oryza sativa) is the main summer or kharif crop (though millets and pulses are also key staples), grown wherever its considerable moisture needs can be met, commonly by rainfall in upland swidden systems and on the lowlands by flooding bunded or dyked fields in paddy systems. The systems are referred to as ‘dry’ and ‘wet’ rice farming respectively. Rice is the primary staple in the eastern or tropical zone receiving the greatest amount of summer monsoon rain. This extends from the Ganges (Ganga) valley eastwards through Assam into Myanmar (Burma) and East Asia. There are something like 100,000 varieties of domesticated Asian rice, but the main one grown in the region is Oryza indica. A wide range of millets is also grown as summer crops in rain-fed systems throughout the semi-arid tropical regions of South Asia, including sorghum or ‘great millet’, finger millet, pearl or bullrush millet, proso or common millet, foxtail millet, bristley foxtail, browntopmillet, kodo millet, littlemillet, and sawamillet.
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Badmaev, Nimazhap Bayarzhapovich, Aleksandr Vladimirovich Bazarov i Roman Sergeevich Sychev. "Forest Fire Danger Assessment Using Meteorological Trends". W Predicting, Monitoring, and Assessing Forest Fire Dangers and Risks, 183–208. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-1867-0.ch008.
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The chapter presents the results of research in the Republic of Buryatia, where the number and area of fires have increased over the past 20 years due to the rise in temperature and aridity. Most of the fires are registered in the large river valleys where pine forests are formed, which have low soil moisture capacity. Fewer fires occurred on the Eastern Sayans, Khamar-Daban ridges, and the Stanovoye Highlands, where the precipitation maximum falls. A correlation analysis was carried out between meteorological parameters and fires in climate-contrasting forests. The lack of precipitation at the end of the previous summer, combined with the hot and dry spring weather of the current year, have a significant impact on fires in the arid ecosystems of the Transbaikal middle mountains. In the humid coastal climate of the Eastern Baikal region, the high temperature of the air determines the fires, but there is no precipitation.
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Juo, Anthony S. R., i Kathrin Franzluebbers. "Properties and Management of Smectitic Soils". W Tropical Soils. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195115987.003.0016.
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Smectitic soils of the tropics are medium- to fine-textured alluvial soils containing moderate to large amounts (20% or more) of smectite, a shrinking and swelling clay mineral, in the clay fraction. Small to moderate amounts of other layer silicate minerals, such as illite, chlorite, vermiculite, and kaolinite, are also present in the clay fraction. Smectitic soils have moderate to high values of CEC (10-50 cmol/kg of soil), high base saturation, and high water-retention capacity. These soils are usually developed on alluvial materials rich in basic cations, especially Mg. Smectitic soils commonly occur on alluvial plains in river valleys and deltas as well as in inland depressions. In the wetter tropics, large areas of smectitic soils are found in tropical Asia, especially Vietnam, Thailand, and Myanmar (Burma). These young alluvial soils are rich in nutrient-bearing weatherable minerals, such as micas, feldspars, and hornblende. Smectitic soils on the alluvial plains and inland valleys have a shallow groundwater table, and some soils are flooded during the rainy season. Thus, they are best suited for rice cultivation. For example, in the flood plains along the Mekong and Chao Phraya rivers of the Indo- China peninsula, mineral-rich deposits from annual flooding are able to maintain relatively high rice yields with little or no additional nutrient inputs. Smectitic soils occurring in seasonally flooded coastal mangrove swamps are known as acid sulfate soils. These soils are used for cultivation of swamp rice and floating rice during the rainy season, depending upon the depth of flooding by fresh water. In drier regions, clayey smectitic soils (mainly Vertisols) often exhibit large cracks during the dry season and become very sticky and difficult to work with during the rainy season. In the drier tropics, large areas of clayey smectitic soils are found in central India, central Sudan, southern Ghana, and in the Lake Chad region of central Africa. Clayey smectitic soils are usually found in the inland depressions scattered throughout the drier regions of West, East and Central Africa. Because of their high chemical fertility, these soils are important soils for cropping and grazing in the drier tropics.
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Woodward, Jamie. "Editorial Introduction". W The Physical Geography of the Mediterranean. Oxford University Press, 2009. http://dx.doi.org/10.1093/oso/9780199268030.003.0017.
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The nine chapters in Part II build on the physical, biological, and theoretical frameworks set out in Part I, but with a focus on process regimes and change in specific environments. With its emphasis on much larger spatial scales, Part I showed how the Mediterranean basin is a product of long-term interactions between all components of the Earth system. It showed how these interactions drive landscape and ecosystem processes and environmental change. The chapters in Part II examine Mediterranean-wide patterns too, but explore process interactions in sharper resolution and across scales ranging from individual soil profiles, hillslopes, and habitats to larger landscape elements including lake basins, river valleys, dune systems, and coastal plains. Much of the region is dominated by mountains and many process interactions are especially vivid in the Mediterranean because of the erosive energy available in steep and active tectonic settings, and the presence of soft rocks vulnerable to mass movements and water erosion. Abrupt transitions from uplands to lowlands— and the differential response to tectonic uplift of hard and soft rock terrains—are notable features. The seasonally dry climate can leave bare slopes exposed to high intensity rains, and river sediment yields are typically much higher than in adjacent regions. It can be argued that the Quaternary records of these interactions are more varied and better preserved than in any other part of the world. Recent major advances include the development of high resolution proxy climate data from speleothems and robust dating frameworks for fluvial, glacial, and palaeoecological records. These records have provided important new insights into the tempo of climate, landscape, and ecosystem change in the Mediterranean region and beyond. A variety of sedimentary archives also provide insights into the changing nature and intensity of human action in the Mediterranean landscape during the course of the Pleistocene and Holocene and this is a core theme of Part II. The region is unique because of the very early and widespread impact of humans in landscape and ecosystem change—and the richness of the archaeological and geological archives in which it is chronicled.
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Searle, Mike. "Roof of the World: Tibet, Pamirs". W Colliding Continents. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199653003.003.0016.
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The Tibetan Plateau is by far the largest region of high elevation, averaging just above 5,000 metres above sea level, and the thickest crust, between 70 and 90 kilometres thick, anywhere in the world. This huge plateau region is very flat—lying in the internally drained parts of the Chang Tang in north and central Tibet, but in parts of the externally drained eastern Tibet, three or four mountain ranges larger and higher than the Alps rise above the frozen plateau. Some of the world’s largest and longest mountain ranges border the plateau, the ‘flaming mountains’ of the Tien Shan along the north-west, the Kun Lun along the north, the Longmen Shan in the east, and of course the mighty Himalaya forming the southern border of the plateau. The great trans-Himalayan mountain ranges of the Pamir and Karakoram are geologically part of the Asian plate and western Tibet but, as we have noted before, unlike Tibet, these ranges have incredibly high relief with 7- and 8-kilometre-high mountains and deeply eroded rivers and glacial valleys. The western part of the Tibetan Plateau is the highest, driest, and wildest area of Tibet. Here there is almost no rainfall and rivers that carry run-off from the bordering mountain ranges simply evaporate into saltpans or disappear underground. Rivers draining the Kun Lun flow north into the Takla Makan Desert, forming seasonal marshlands in the wet season and a dusty desert when the rivers run dry. The discovery of fossil tropical leaves, palm tree trunks, and even bones from miniature Miocene horses suggest that the climate may have been wetter in the past, but this is also dependent on the rise of the plateau. Exactly when Tibet rose to its present elevation is a matter of great debate. Nowadays the Indian Ocean monsoon winds sweep moisture-laden air over the Indian sub-continent during the summer months (late June–September). All the moisture is dumped as the summer monsoon, the torrential rains that sweep across India from south-east to north-west.
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Fountain, Andrew G., i W. Berry Lyons. "Century- to Millennial-Scale Climate Change and Ecosystem Response in Taylor Valley, Antarctica". W Climate Variability and Ecosystem Response in Long-Term Ecological Research Sites. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195150599.003.0031.
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The view of climate change during the Pleistocene and the Holocene was very much different a mere decade ago. With the collection and detailed analyses of ice core records from both Greenland and Antarctica in the early and mid-1990s, respectively, the collective view of climate variability during this time period has changed dramatically. During the Pleistocene, at least as far back as 450,000 years b.p., abrupt and severe temperature fluctuations were a regular occurrence rather than the exception (Mayewski et al. 1996, 1998; Petit et al. 1999). During the Pleistocene, these rapid and large climatic fluctuations, initially identified in the ice core records, have been verified in both marine and lacustrine sediments as well (Bond et al. 1993; Grimm et al. 1993), suggesting large-scale (hemispheric to global) climate restructuring over very short periods of time (Mayewski et al. 1997). Similar types of climatic fluctuations, but with smaller amplitudes, have also occurred during the Holocene (O’Brien et al. 1995; Bond et al. 1997; Arz et al. 2001). What were the biological responses to these changes in temperature, precipitation, and atmospheric chemistry? We must answer this question if we are to understand the century- to millennial-scale influence of climate on the structure and function of ecosystems. Because the polar regions are thought to be amplifiers of global climate change, these regions are ideal for investigating the response of ecological systems to, what in temperate regions might be considered, small-scale climatic variation. Our knowledge of past climatic variations in Antarctica comes from different types of proxy records, including ice core, geologic, and marine (Lyons et al. 1997). It is clear, however, that coastal Antarctica may respond to oceanic, atmospheric, and ice sheet–based climatic “drivers,” and therefore ice-free regions, such as the Mc- Murdo Dry Valleys, may respond to climate change in a much more complex manner than previously thought (R. Poreda, unpubl. data 2001). Since the initiation of the McMurdo Dry Valleys Long-Term Ecological Research program (MCM) in 1993, there has been a keen interest not only in the dynamics of the present day ecosystem, but also in the legacies produced via past climatic variation on the ecosystem. In this chapter we examine the current structure and function of the dry valleys ecosystem from the perspective of our work centered in Taylor Valley.
Streszczenia konferencji na temat "Dry Valleys Region"
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Haproff, Peter, Drew Levy, Andrew V. Zuza i Jordan D. Burkey. "PRELIMINARY CONSTRAINTS ON THE QUATERNARY SLIP HISTORIES OF THE EUREKA VALLEY FAULT AND THE DRY MOUNTAIN FAULT WITHIN THE EASTERN CALIFORNIA SHEAR ZONE, DEATH VALLEY REGION". W GSA 2020 Connects Online. Geological Society of America, 2020. http://dx.doi.org/10.1130/abs/2020am-353395.
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Wong, Kaufui V., i Sarmad Chaudhry. "Climate Change Aggravates the Energy-Water-Food Nexus". W ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36502.
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There are regions in the world experiencing the energy-food-water nexus problems. These regions tend to have high population density, economy that depends on agriculture and climates with lower annual rainfall that may have been adversely affected by climate change. A case in point is the river basin of the Indus. The Indus River is a large and important river running through four countries in East Asia and South Asia: China, India, Afghanistan, and Pakistan. The region is highly dependent on water for both food and energy. The interlinkage of these three components is the cause for the energy-water-food nexus. The difficulty in effectively managing the use of these resources is their very interdependence. For instance, water availability and policies may influence food production, which is governed by agricultural policies, which will further affect energy production from both water and biofuel sources, which will in turn require the usage of water. The situation is further complicated when climate change is taken into account. On the surface, an increase in temperatures would be devastating during the dry season for a region that uses up to 70% of the total land for agriculture. There are predictions that crop production in the region would decrease; the Threedegreeswarmer organization estimated that crop production in the region could decrease by up to 30% come 2050. Unfortunately, the suspected effects of climate change are more than just changes in temperature, precipitation, monsoon patterns, and drought frequencies. A huge concern is the accelerating melting of glaciers in the Himalayas. Some models predict that a global increase in temperature of just 1°C can decrease glacial volume by 50%. The loss of meltwaters from the Himalayan glaciers during the dry season will be crippling for the Indus River and Valley. In a region where up to 90% of accessible water is used for agriculture, there will be an increased strain on food supply. This will further deteriorate the current situation in the region, where almost half of the world’s hungry and undernourished people reside. While the use of hydropower to generate electricity is already many times lower than the potential use, future scarcity of water will limit the potential ability of hydropower to supply energy to people who already experience less than 50% access to electricity. In the current work, suggestions have been put forward to save the increased glacier melt for current and future use where necessary, improve electricity generation efficiency, use sea water for Rankine power cycle cooling and combined cycle cooling, and increase use desalination for drinking water. Energy conservation practices should also be practiced. All of these suggestions must be considered to address the rising issues in the energy-water-food nexus.
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Deleanu, Lorena, Gabriel Andrei i Laura Maftei. "Surface Characterization of Polymer Composite Using Bearing Area Curve". W ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2010. http://dx.doi.org/10.1115/esda2010-25330.
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This paper presents an analysis of several 3D parameters based on bearing area curve in order to use the information for establishing the influence of sliding regime against steel on the tribological behavior of a composite class with polyamide matrix and 1% of black carbon. There were done pin-on-disk tests for different concentrations of micro glass spheres (MGS): 2.5, 5, 10, 20, 30 and 50% (wt), respectively. The polymer was tested under similar conditions in order to have a reference basis and to point out the improvement in tribological behavior when adding this reinforcement material. The surface topographies were registered with the help of PRO500 3D (stylus) Profilometer. The test parameters in dry regime were: sliding speed 0.5, 1.0 and 1.5 m/s, average pressure 1, 2 and 3 MPa, respectively. There were analyzed the influence of MGS concentration and sliding regime on wear as mass loss of the composite discs, after 10,000 m of sliding, the friction coefficient and several 3D parameters related to the bearing area curve, determined from raw profiles (surface bearing index – Sbi, core fluid retention index – Sci, valley fluid retention index, Svi, reduced summit height, Spk, core roughness depth, Sk, and reduced valley depth, Svk).
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Matsui, Y., T. Suzuki, P. Deevanhxay, S. Tsushima i S. Hirai. "Crack Generation in Catalyst Layer and Micro Porous Layer by Wet-Dry Cycles and its Impact on PEMFC Performance". W ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology collocated with the ASME 2013 Heat Transfer Summer Conference and the ASME 2013 7th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/fuelcell2013-18099.
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In this study, we focused on nano- and micro-scale cracks in the catalyst layer and the micro porous layer of polymer electrolyte membrane fuel cells (PEMFCs) and its impact on cell performance. We applied wet-dry cycles to a conventional test cell to investigate crack generation in the catalyst layer and the micro porous layer. Wet-dry cycles, in which cell temperature was kept at 353K with high- and low-humidified gas alternately applied to the cell, potentially induced mechanical stress to a membrane electrode assembly (MEA) due to membrane hydration and dehydration. As a result, significant degradation of performance was found after the wet-dry cycles. We performed cross-sectional analysis of MEA by using a cross-sectional polisher (CP) and scanning electron microscopy (SEM) to investigate nano- and micro-scale crack generated by the wet-dry cycles in the MEA. The SEM images showed that nano- and micro-scale cracks were significantly generated in the catalyst layer as well as in the micro porous layer after the cycles. We identified cracks in the MEA with different morphologies according to the SEM images, hence, through-plane cracks and in-plane cracks. Through-plane cracks have a deep-valley structure in the MEA while in-plane cracks are formed in an interfacial region between the catalyst layer and the micro porous layer. In-plane cracks could be generated by detachment of the catalyst layer from the micro porous layer due to the wet-dry cycles and potentially decrease in cell performance due to deterioration of electron transport in the MEA. In addition, in case liquid water is accumulated in in-plane cracks, these cracks potentially disturb gas diffusion from the micro porous layer to the catalyst layer. These results clearly showed that mechanical stress induced crack generation in the MEA, resulting in intensive effects on cell performance in PEMFC.
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Lal, Manish Kumar, Tae Hyung Kim i Darrin M. Singleton. "Data Science Use Case for Brownfield Optimization - A Case Study". W SPE Western Regional Meeting. SPE, 2021. http://dx.doi.org/10.2118/200781-ms.
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Abstract Data Science is the current gold rush. While many industries have benefitted from applications of data science, including machine learning and Artificial Intelligence (AI), the applications in upstream oil and gas are still somewhat limited. Some examples of applications of AI include seismic interpretations, facility optimization, and data driven modeling – forecasting. While still naïve, we will explore cases where data science can be used in the day to day field optimization and development. The Midway Sunset (MWSS) field in San Joaquin Valley, California has over 100 years of history. The field was discovered in 19011 and had limited development through the 1960s. Since the start of thermal stimulation in 1964, the field has seen phased thermal flooding and cyclic stimulation. Recently there has been an increase in heat mining vertical and horizontal wells to tap the remaining hot oil. As with any brownfield, the sweet spots are long gone. Effort is now to optimize the field development and tap by-passed oil, thereby increasing recovery. The current operational focus includes field wide holistic review of remaining resource potential. Resources in the MWSS reservoirs are produced by cyclic steam method. Cyclic thermal stimulation has been effective as an overall depletion process and for stimulating the near wellbore region to increase production. It is imperative to properly identify target wells and sands for cyclic stimulation. Cyclic steaming in depleted zones or cold reservoirs is often uneconomical. The benefit comes when we can identify and stimulate only the warm oil. Identification of warm oil and short listing the wells for cyclic stimulation is a labor-intensive process. The volume of data can get so large that it may not be feasible for a professional to effectively do the analysis. In this paper, we present a case study of data analytics for high grading wells for cyclic stimulation. This method utilizes the machine power to integrate reservoir, and production data to identify and rank wells for cyclic stimulation and potentially increase success rate by minimizing suboptimal cyclic candidates.
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MOSIEJ, Józef, i Teresa SUCHECKA. "THE ROLE OF IRRIGATION IN RIVER VALLEYS TO DEVELOP WATER QUALITY, PRODUCTION OF BIOMASS AND SUSTAINABLE RURAL DEVELOPMENT - CASE STUDY". W RURAL DEVELOPMENT. Aleksandras Stulginskis University, 2018. http://dx.doi.org/10.15544/rd.2017.076.
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Ner river and its valley for over 170 years has been receiver for sewages from the city of Łódź. The natural system of this region (on the border of the watershed location, limitations of water supplies sources, lack of bigger natural rivers) in connection to city growth, lead to forming of specific system involving an agglomeration and water supplies system as well as wastewaters utilization system. The Ner river valley has the great potential to be effective in production biomass for energy purposes. Irrigation with polluted Ner river water cover fast growing plants high water and nutritional requirements. This would also work for the improvement of Ner river water quality. The achievement of good quality of water is not possible without irrigation of agricultural land in river valley. An amount of sewage discharged to Ner (193,017 m³ per day) several times higher then its natural flow in river. This is a result of strategy of water supply that is supported by transfer of water from Pilica river and underground water uptake for agglomeration. Relatively high runoff coefficient in years 1952 – 2011 was equal to 0.325 for Ner, in comparison to 0.17 for other rivers in Warta watershed. Despite the low natural flow Ner river discharges annually relatively high contaminants’ load to Warta river. In the analysed period (1995-2003) the annual average flow of Ner river amounted 10 % of annual average Warta river flow below its estuary. The share of analysed indicators of contaminants’ load approximated 27 % for total nitrogen, 37 % for phosphorus, 39 % for BOD5 and 28% for suspended solids. In the period 2004-2011 the annual average flow of Ner river amounted 13.8 % of annual average Warta river flow. The share of investigated pollutants loads consists 27.9 % for total nitrogen, 42.6 % for phosphorus, 19.8 % for BOD5 and 19.6 % for suspended solids.
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Davis, John C., Mike Jones i John Roderique. "Planning for Greater Levels of Diversion That Including Energy Recovery for the Mojave Desert and Mountain Recycling Authority, California Region". W 17th Annual North American Waste-to-Energy Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/nawtec17-2342.
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The Mojave Desert and Mountain Recycling Authority is a California Joint Powers Authority (the JPA), consisting of nine communities in California’s San Bernardino County high desert and mountain region. In August 2008 the JPA contracted with Gershman, Brickner & Bratton, Inc. (GBB) to prepare the Victor Valley Resource Management Strategy (Resource Management Strategy). Working with RRT Design and Construction, Inc. (RRT), GBB prepared a coordinated forward-looking strategy to guide the JPA’s future program and facilities decisions. The Resource Management Strategy focused on the Town of Apple Valley, population 70,092, and the City of Victorville, population 107,408, the two largest JPA member communities, which have a combined total of more than 130,000 tons per year of material entering the JPA’s recycling system and the Victorville Landfill. The Resource Management Strategy is underpinned by a characterization of waste loads delivered to the Victorville Landfill. A visual characterization was carried out by RRT in September/October 2008. RRT engineers identified proportions of materials recoverable for recycling and composting among all loads collected from residential and non-residential generators for a full week, nearly 300 loads total. The JPA financed and manages the operations contract for the highly automated Victor Valley Material Recovery Facility (MRF). The MRF today receives and processes an average of 130 tons per day (tpd), five days per week, of single stream paper and containers and recyclable-rich commercial waste loads. The waste characterization indicated that as much as 80 percent of loads of residential and commercial waste currently landfilled could be processed for recycling and composting in a combination manual and automated sorting facility. Residue from the MRF, which is predominated by paper, would provide potential feedstock for an energy recovery project; however, the JPA has two strategies regarding process residue. The first strategy is to reduce residue rates from existing deliveries, to optimize MRF operations. An assessment of the MRF conducted by RRT indicated that residue rates could be reduced, although this material would continue to be rich in combustible materials. The second strategy is to increase recovery for recycling by expanding the recyclable-rich and organics-dense waste load deliveries to the MRF and/or a composting facility. The Resource Management Strategy provided a conceptual design and cost that identified projected capital and operations costs that would be incurred to expand the MRF processing system for the program expansion. Based on the waste composition analysis, residue from a proposed system was estimated. This residue also would be rich in combustible materials. The December 2008 California Scoping Plan is the roadmap for statewide greenhouse gas emission reduction efforts. The Scoping Plan specifically calls out mandatory commercial recycling, expanded organics composting (particularly food residue), and inclusion of anaerobic digestion as renewable energy. The Resource Management Strategy sets the stage for JPA programs to address Scoping Plan mandates and priorities. California Public Resources Code Section 40051(b) requires that communities: Maximize the use of all feasible source reduction, recycling, and composting options in order to reduce the amount of solid waste that must be disposed of by transformation and land disposal. For wastes that cannot feasibly be reduced at their source, recycled, or composted, the local agency may use environmentally safe transformation or environmentally safe land disposal, or both of those practices. Moreover, Section 41783(b) only allows transformation diversion credit (10 percent of the 50 percent required) if: The transformation project uses front-end methods or programs to remove all recyclable materials from the waste stream prior to transformation to the maximum extent feasible. Finally, prior to permitting a new transformation facility the California Integrated Waste Management Board is governed by Section 41783(d), which requires that CIWMB: “Hold a public hearing in the city, county, or regional agency jurisdiction within which the transformation project is proposed, and, after the public hearing, the board makes both of the following findings, based upon substantial evidence on the record: (1) The city, county, or regional agency is, and will continue to be, effectively implementing all feasible source reduction, recycling, and composting measures. (2) The transformation project will not adversely affect public health and safety or the environment.” The Resource Management Strategy assessed two cement manufacturers located in the high desert region for their potential to replace coal fuel with residue from the MRF and potentially from other waste quantities generated in the region. Cement kilns are large consumers of fossil fuels, operate on a continuous basis, and collectively are California’s largest source of greenhouse gas emissions. The Resource Management Strategy also identified further processing requirements for size reduction and screening to remove non-combustible materials and produce a feasible refuse derived fuel (RDF). A conceptual design system to process residue and supply RDF to a cement kiln was developed, as were estimated capital and operating costs to implement the RDF production system. The Resource Management Strategy addressed the PRC requirement that “all feasible source reduction, recycling and composting measures” are implemented prior to approving any new “transformation” facility. This planning effort also provided a basis for greenhouse gas reduction analysis, consistent with statewide initiatives to reduce landfill disposal. This paper will report on the results of this planning and the decisions made by the JPA, brought current to the time of the conference.
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Wu, Hong, S. Nasir, W. F. Ng i H. K. Moon. "Showerhead Film Cooling Performance of a Transonic Turbine Vane at High Freestream Turbulence (Tu = 16%): 3-D CFD and Comparison With Experiment". W ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-67782.
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The main objective of the study reported here is to use 3-D CFD to calculate and explain adiabatic film cooling effectiveness and Nusselt number distributions downstream of the showerhead film cooling rows of a turbine vane at high freestream turbulence and realistic exit Reynolds number/Mach number condition. The paper discusses a three-simulations technique to calculate vane surface recovery temperature, adiabatic wall temperature, and surface Nusselt number to completely characterize film cooling performance in a high speed flow. The RANS based ν2-f turbulence model, originally suggested by Durbin [1], is used in all numerical predictions. The vane midspan numerical calculations are compared with the experimental results obtained with the showerhead film cooled vane instrumented with single-sided platinum thin film gauges at the midspan and arranged in a two-dimensional, linear cascade in a heated, transonic, blow-down wind tunnel. Exit Mach number of Mex = 0.76—corresponding to exit Reynolds numbers based on vane chord of 1.1 × 106—was tested with an inlet free stream turbulence intensity (Tu) of 16% and an integral length scale normalized by vane pitch (Λx/P) of 0.23. A showerhead cooling scheme with five rows of cooling holes was tested at blowing ratios of BR = 0 and 1.5, and a density ratio of DR = 1.3. CFD predictions performed with experiment-matched boundary conditions show an overall good trend agreement with experimental adiabatic film cooling effectiveness and Nusselt number distributions downstream of the showerhead film cooling rows of the vane. For the experimental data, the primary effects of coolant injection are to augment Nusselt number and reduce adiabatic wall temperature downstream of the injection on the vane surface as compared to no film injection case (BR = 0) at Mex = 0.76. Similar to experimental results, the adiabatic film cooling effectiveness prediction on the suction surface at BR = 1.5 is found to be influenced by favorable pressure gradient due to Mach number through changes in local adiabatic wall and recovery temperature. The Nusselt number prediction on the suction surface shows a peak and a valley downstream of the film cooling rows in a favorable pressure gradient region for both tested blowing ratio conditions. This trend is also observed in the experimental results.
Raporty organizacyjne na temat "Dry Valleys Region"
1
Wright, Kirsten. Collecting Plant Phenology Data In Imperiled Oregon White Oak Ecosystems: Analysis and Recommendations for Metro. Portland State University, marzec 2020. http://dx.doi.org/10.15760/mem.64.
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Highly imperiled Oregon white oak ecosystems are a regional conservation priority of numerous organizations, including Oregon Metro, a regional government serving over one million people in the Portland area. Previously dominant systems in the Pacific Northwest, upland prairie and oak woodlands are now experiencing significant threat, with only 2% remaining in the Willamette Valley in small fragments (Hulse et al. 2002). These fragments are of high conservation value because of the rich biodiversity they support, including rare and endemic species, such as Delphinium leucophaeum (Oregon Department of Agriculture, 2020). Since 2010, Metro scientists and volunteers have collected phenology data on approximately 140 species of forbs and graminoids in regional oak prairie and woodlands. Phenology is the study of life-stage events in plants and animals, such as budbreak and senescence in flowering plants, and widely acknowledged as a sensitive indicator of environmental change (Parmesan 2007). Indeed, shifts in plant phenology have been observed over the last few decades as a result of climate change (Parmesan 2006). In oak systems, these changes have profound implications for plant community composition and diversity, as well as trophic interactions and general ecosystem function (Willis 2008). While the original intent of Metro’s phenology data-collection was to track long-term phenology trends, limitations in data collection methods have made such analysis difficult. Rather, these data are currently used to inform seasonal management decisions on Metro properties, such as when to collect seed for propagation and when to spray herbicide to control invasive species. Metro is now interested in fine-tuning their data-collection methods to better capture long-term phenology trends to guide future conservation strategies. Addressing the regional and global conservation issues of our time will require unprecedented collaboration. Phenology data collected on Metro properties is not only an important asset for Metro’s conservation plan, but holds potential to support broader research on a larger scale. As a leader in urban conservation, Metro is poised to make a meaningful scientific contribution by sharing phenology data with regional and national organizations. Data-sharing will benefit the common goal of conservation and create avenues for collaboration with other scientists and conservation practitioners (Rosemartin 2013). In order to support Metro’s ongoing conservation efforts in Oregon white oak systems, I have implemented a three-part master’s project. Part one of the project examines Metro’s previously collected phenology data, providing descriptive statistics and assessing the strengths and weaknesses of the methods by which the data were collected. Part two makes recommendations for improving future phenology data-collection methods, and includes recommendations for datasharing with regional and national organizations. Part three is a collection of scientific vouchers documenting key plant species in varying phases of phenology for Metro’s teaching herbarium. The purpose of these vouchers is to provide a visual tool for Metro staff and volunteers who rely on plant identification to carry out aspects of their job in plant conservation. Each component of this project addresses specific aspects of Metro’s conservation program, from day-to-day management concerns to long-term scientific inquiry.