WorldWideScience

Sample records for sand sagebrush vegetation

  1. Vegetation responses to sagebrush-reduction treatments measured by satellites

    Science.gov (United States)

    Johnston, Aaron; Beever, Erik; Merkle, Jerod A.; Chong, Geneva W.

    2018-01-01

    Time series of vegetative indices derived from satellite imagery constitute tools to measure ecological effects of natural and management-induced disturbances to ecosystems. Over the past century, sagebrush-reduction treatments have been applied widely throughout western North America to increase herbaceous vegetation for livestock and wildlife. We used indices from satellite imagery to 1) quantify effects of prescribed-fire, herbicide, and mechanical treatments on vegetative cover, productivity, and phenology, and 2) describe how vegetation changed over time following these treatments. We hypothesized that treatments would increase herbaceous cover and accordingly shift phenologies towards those typical of grass-dominated systems. We expected prescribed burns would lead to the greatest and most-prolonged effects on vegetative cover and phenology, followed by herbicide and mechanical treatments. Treatments appeared to increase herbaceous cover and productivity, which coincided with signs of earlier senescence − signals expected of grass-dominated systems, relative to sagebrush-dominated systems. Spatial heterogeneity for most phenometrics was lower in treated areas relative to controls, which suggested treatment-induced homogenization of vegetative communities. Phenometrics that explain spring migrations of ungulates mostly were unaffected by sagebrush treatments. Fire had the strongest effect on vegetative cover, and yielded the least evidence for sagebrush recovery. Overall, treatment effects were small relative to those reported from field-based studies for reasons most likely related to sagebrush recovery, treatment specification, and untreated patches within mosaicked treatment applications. Treatment effects were also small relative to inter-annual variation in phenology and productivity that was explained by temperature, snowpack, and growing-season precipitation. Our results indicated that cumulative NDVI, late-season phenometrics, and spatial

  2. Effectiveness of prescribed fire to re-establish sagebrush vegetation and ecohydrologic function on woodland-encroached sagebrush steppe, Great Basin, USA

    Science.gov (United States)

    Williams, C. J.; Pierson, F. B.; Kormos, P.; Al-Hamdan, O. Z.; Nouwakpo, S.; Weltz, M.; Vega, S.; Lindsay, K.

    2017-12-01

    Range expansion of pinyon (Pinus spp.) and juniper (Juniperus spp.) conifers into sagebrush steppe (Artemisia spp.) communities has imperiled a vast domain in the western US. Encroachment of sagebrush ecosystems by pinyon and juniper conifers has negative ramifications to ecosystem structure and function and delivery of goods and services. Scientists, land management agencies, and private land owners throughout the western US are challenged with selecting from a suite of options to reduce pinyon and juniper woody fuels and re-establish sagebrush steppe structure and function. This study evaluated the effectiveness of prescribed fire to re-establish sagebrush vegetation and ecohydrologic function over a 9 yr period. Nine years post-fire hydrologic and erosion responses reflect the combination of pre-fire site conditions, perennial grass recruitment, delayed litter cover, and inherent site characteristics. Burning initially increased bare ground, runoff, and erosion for well-vegetated areas underneath tree and shrub canopies, but had minimal impact on hydrology and erosion for degraded interspaces between plants. The degraded interspaces were primarily bare ground and exhibited high runoff and erosion rates prior to burning. Initial fire effects persisted for two years, but increased productivity of grasses improved hydrologic function of interspaces over the full 9 yr period. At the hillslope scale, grass recruitment in the intercanopy between trees reduced runoff from rainsplash, sheetflow, and concentrated overland flow at one site, but did not reduce the high levels of runoff and erosion from a more degraded site. In areas formerly occupied by trees (tree zones), burning increased invasive annual grass cover due to fire removal of limited native perennial plants and competition for resources. The invasive annual grass cover had no net effect on runoff and erosion from tree zones however. Runoff and erosion increased in tree zones at the more degraded site due to

  3. Using Unmanned Aerial Vehicles to Assess Vegetative Cover in Sagebrush Steppe Ecosytstems

    Energy Technology Data Exchange (ETDEWEB)

    Robert P. Breckenridge

    2005-09-01

    The Idaho National Laboratory (INL), in conjunction with the University of Idaho, is evaluating novel approaches for using unmanned aerial vehicles (UAVs) as a quicker and safer method for monitoring biotic resources. Evaluating vegetative cover is an important factor in understanding the sustainability of many ecosystems. In assessing vegetative cover, methods that improve accuracy and cost efficiency could revolutionize how biotic resources are monitored on western federal lands. Sagebrush steppe ecosystems provide important habitat for a variety of species, some of which are important indicator species (e.g., sage grouse). Improved methods are needed to support monitoring these habitats because there are not enough resource specialists or funds available for comprehensive ground evaluation of these ecosystems. In this project, two types of UAV platforms (fixed wing and helicopter) were used to collect still-frame imagery to assess cover in sagebrush steppe ecosystems. This paper discusses the process for collecting and analyzing imagery from the UAVs to (1) estimate total percent cover, (2) estimate percent cover for six different types of vegetation, and (3) locate sage grouse based on representative decoys. The field plots were located on the INL site west of Idaho Falls, Idaho, in areas with varying amounts and types of vegetative cover. A software program called SamplePoint developed by the U.S. Department of Agriculture, Agricultural Research Service (USDA-ARS) was used to evaluate the imagery for percent cover for the six vegetation types (bare ground, litter, shrubs, dead shrubs, grasses, and forbs). Results were compared against standard field measurements to assess accuracy.

  4. Simulating the Dependence of Sagebrush Steppe Vegetation on Redistributed Snow in a Semi-Arid Watershed.

    Science.gov (United States)

    Soderquist, B.; Kavanagh, K.; Link, T. E.; Strand, E. K.; Seyfried, M. S.

    2014-12-01

    In mountainous regions across the western USA, the composition of aspen (Populus tremuloides) and sagebrush steppe plant communities is often closely related to heterogeneous soil moisture subsidies resulting from redistributed snow. With decades of climate and precipitation data across elevational and precipitation gradients, the Reynolds Creek Experimental Watershed (RCEW) and critical zone observatory (CZO) in southwest Idaho provides a unique opportunity to study the relationship between vegetation types and redistributed snow. Within the RCEW, the total amount of precipitation has remained unchanged over the past 50 years, however the percentage of the precipitation falling as snow has declined by approximately 4% per decade at mid-elevation sites. As shifts in precipitation phase continue, future trends in vegetation composition and net primary productivity (NPP) of different plant functional types remains a critical question. We hypothesize that redistribution of snow may supplement drought sensitive species like aspen more so than drought tolerant species like mountain big sagebrush (Artemisia tridentata spp. vaseyana). To assess the importance of snowdrift subsidies on sagebrush steppe vegetation, NPP of aspen, shrub, and grass species was simulated at three sites using the biogeochemical process model BIOME-BGC. Each site is located directly downslope from snowdrifts providing soil moisture inputs to aspen stands and neighboring vegetation. Drifts vary in size with the largest containing up to four times the snow water equivalent (SWE) of a uniform precipitation layer. Precipitation inputs used by BIOME-BGC were modified to represent the redistribution of snow and simulations were run using daily climate data from 1985-2013. Simulated NPP of annual grasses at each site was not responsive to subsidies from drifting snow. However, at the driest site, aspen and shrub annual NPP was increased by as much as 44 and 30%, respectively, with the redistribution of

  5. Selection of anthropogenic features and vegetation characteristics by nesting Common Ravens in the sagebrush ecosystem

    Science.gov (United States)

    Howe, Kristy B.; Coates, Peter S.; Delehanty, David J.

    2014-01-01

    Common Raven (Corvus corax) numbers and distribution are increasing throughout the sagebrush steppe, influencing avian communities in complex ways. Anthropogenic structures are thought to increase raven populations by providing food and nesting subsidies, which is cause for concern because ravens are important nest predators of sensitive species, including Greater Sage-Grouse (Centrocercus urophasianus). During 2007–2009, we located raven nests in southeastern Idaho and conducted a resource selection analysis. We measured variables at multiple spatial scales for 72 unique nest locations, including landscape-level vegetation characteristics and anthropogenic structures. Using generalized linear mixed models and an information-theoretic approach, we found a 31% decrease in the odds of nesting by ravens for every 1 km increase in distance away from a transmission line. Furthermore, a 100-m increase in distance away from the edge of two different land cover types decreased the odds of nesting by 20%, and an increase in the amount of edge by 1 km within an area of 102.1 ha centered on the nest increased the odds of nesting by 49%. A post hoc analysis revealed that ravens were most likely to nest near edges of adjoining big sagebrush (Artemisia tridentata) and land cover types that were associated with direct human disturbance or fire. These findings contribute to our understanding of raven expansion into rural environments and could be used to make better-informed conservation decisions, especially in the face of increasing renewable energy development.

  6. Ecogeomorphology of Sand Dunes Shaped by Vegetation

    Science.gov (United States)

    Tsoar, H.

    2014-12-01

    Two dune types associated with vegetation are known: Parabolic and Vegetated Linear Dunes (VLDs), the latters are the dominant dune type in the world deserts. Parabolic dunes are formed in humid, sub-humid and semi-arid environments (rather than arid) where vegetation is nearby. VLDs are known today in semiarid and arid lands where the average yearly rainfall is ≥100 mm, enough to support sparse cover of vegetation. These two dune types are formed by unidirectional winds although they demonstrate a different form and have a distinct dynamics. Conceptual and mathematical models of dunes mobility and stability, based on three control parameters: wind power (DP), average annual precipitation (p), and the human impact parameter (μ) show that where human impact is negligible the effect of wind power (DP) on vegetative cover is substantial. The average yearly rainfall of 60-80 mm is the threshold of annual average rainfall for vegetation growth on dune sand. The model is shown to follow a hysteresis path, which explains the bistability of active and stabilized dunes under the same climatic conditions with respect to wind power. We have discerned formation of parabolic dunes from barchans and transverse dunes in the coastal plain of Israel where a decrease in human activity during the second half of the 20th century caused establishment of vegetation on the crest of the dunes, a process that changed the dynamics of these barchans and transverse dunes and led to a change in the shape of the windward slope from convex to concave. These dunes gradually became parabolic. It seems that VLDs in Australia or the Kalahari have always been vegetated to some degree, though the shrubs were sparser in colder periods when the aeolian erosion was sizeable. Those ancient conditions are characterized by higher wind power and lower rainfall that can reduce, but not completely destroy, the vegetation cover, leading to the formation of lee (shadow) dunes behind each shrub. Formation of

  7. Success of seeding native compared with introduced perennial vegetation for revegetating medusahead-invaded sagebrush rangeland

    Science.gov (United States)

    Millions of hectares of Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle &Young) rangeland have been invaded by medusahead (Taeniatherum caput-medusae [L.] Nevski), an exotic annual grass that degrades wildlife habitat, reduces forage production, and decreases biodiversity....

  8. Effects of sand fences on coastal dune vegetation distribution

    Science.gov (United States)

    Grafals-Soto, Rosana

    2012-04-01

    Sand fences are important human adjustments modifying the morphology of developed shores. The effects of sand fences on sediment transport and deposition in their initial stages have been well studied, but little is known about the effect of deteriorated sand fences that have become partially buried low scale barriers within the dune, potentially benefiting vegetation growth by protecting it from onshore stress. Data on vegetation, topography and fence characteristics were gathered at three dune sites in Ocean City, New Jersey on September 2007 and March 2008 to evaluate the effect of fences within the dune on vegetation distribution. Variables include: distance landward of dune toe, degree of sheltering from onshore stressors, net change in surface elevation (deposition or erosion), vegetation diversity and density, presence of remnant fence, and distance landward of fence. Results for the studied environment reveal that 1) vegetation diversity or density does not increase near remnant fences because most remnants are lower than average vegetation height and can not provide shelter; but 2) vegetation distribution is related to topographic variables, such as degree of sheltering, that are most likely the result of sand accretion caused by fence deployment. Fence deployment that prioritizes the creation of topographically diverse dunes within a restricted space may increase the diversity and density of the vegetation, and the resilience and value of developed dunes. Managers should consider the benefits of using sand fences on appropriately wide beaches to create a protective dune that is also diverse, functional and better able to adapt to change.

  9. Using Unmanned Aerial Vehicles to Assess Vegetative Cover and Identify Biotic Resources in Sagebrush Steppe Ecosystems: Preliminary Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Robert P. Breckenridge

    2006-04-01

    The Idaho National Laboratory (INL), in conjunction with the University of Idaho, is evaluating novel approaches for using unmanned aerial vehicles (UAVs) as a quicker and safer method for monitoring biotic resources. Evaluating vegetative cover is an important factor in understanding the sustainability of many ecosystems. In assessing vegetative cover, methods that improve accuracy and cost efficiency could revolutionize how biotic resources are monitored on western federal lands. Sagebrush steppe ecosystems provide important habitat for a variety of species, some of which are important indicator species (e.g., sage grouse). Improved methods are needed to support monitoring these habitats because there are not enough resource specialists or funds available for comprehensive ground evaluation of these ecosystems. In this project, two types of UAV platforms (fixed wing and helicopter) were used to collect still-frame imagery to assess cover in sagebrush steppe ecosystems. This paper discusses the process for collecting and analyzing imagery from the UAVs to (1) estimate total percent cover, (2) estimate percent cover for six different types of vegetation, and (3) locate sage grouse based on representative decoys. The field plots were located on the INL site west of Idaho Falls, Idaho, in areas with varying amounts and types of vegetative cover. A software program called SamplePoint developed by the U.S. Department of Agriculture, Agricultural Research Service was used to evaluate the imagery for percent cover for the six vegetation types (bare ground, litter, shrubs, dead shrubs, grasses, and forbs). Results were compared against standard field measurements to assess accuracy.

  10. [Process study on hysteresis of vegetation cover influencing sand-dust events].

    Science.gov (United States)

    Xu, Xing-Kui; Wang, Xiao-Tao; Zhang, Feng

    2009-02-15

    Data analysis from satellite and weather stations during 1982-2000 shows nonlinear relationship between vegetation cover and sand-dust events is present in most part of China. Vegetation cover ratio in summer can impact significantly on the frequency of sand-dust storms from winter to spring in the source regions of sand-dust events. It is not quite clear about the hysteresis that vegetation cover in summer influence sand-dust events during winter and spring. A quasi-geostrophic barotropic model is used under the condition of 3 magnitude of frictional coefficient to investigate the cause of the hysteresis. Wind velocity shows a greatest decline at 90% during 72 h as initial wind velocity is 10 m/s for magnitude of frictional coefficient between atmosphere and water surface, greatest decline at 100% during 18 h for magnitude of frictional coefficient between atmosphere and bare soil and a 100% reduction of wind speed during 1 h for magnitude of frictional coefficient between atmosphere and vegetation cover. Observation and simulation prove that residual root and stem from summervegetation are one of factors to influence sand-dust events happened during winter and spring. Air inhibition from residual root and stem is a most important reason for hysteresis that vegetation cover influence sand-dust events.

  11. Grassland canopy parameters and their relationships to remotely sensed vegetation indices in the Nebraska Sand Hills

    Science.gov (United States)

    Wylie, Bruce K.; DeJong, Donovan D.; Tieszen, Larry L.; Biondini, Mario E.

    1996-01-01

    Relationships among spectral vegetation indices and grassland biophysical parameters including the effects of varying levels of standing dead vegetation, range sites, and range plant communities were examined. Range plant communities consisting of northern mixed grass prairie and a smooth brome field as well as range sites and management in a Sand Hills bluestem prairie were sampled with a ground radiometer and for LAI, biomass, chlorophy

  12. Compositional Signatures in Acoustic Backscatter Over Vegetated and Unvegetated Mixed Sand-Gravel Riverbeds

    Science.gov (United States)

    Buscombe, D.; Grams, P. E.; Kaplinski, M. A.

    2017-10-01

    Multibeam acoustic backscatter has considerable utility for remote characterization of spatially heterogeneous bed sediment composition over vegetated and unvegetated riverbeds of mixed sand and gravel. However, the use of high-frequency, decimeter-resolution acoustic backscatter for sediment classification in shallow water is hampered by significant topographic contamination of the signal. In mixed sand-gravel riverbeds, changes in the abiotic composition of sediment (such as homogeneous sand to homogeneous gravel) tend to occur over larger spatial scales than is characteristic of small-scale bedform topography (ripples, dunes, and bars) or biota (such as vascular plants and periphyton). A two-stage method is proposed to filter out the morphological contributions to acoustic backscatter. First, the residual supragrain-scale topographic effects in acoustic backscatter with small instantaneous insonified areas, caused by ambiguity in the local (beam-to-beam) bed-sonar geometry, are removed. Then, coherent scales between high-resolution topography and backscatter are identified using cospectra, which are used to design a frequency domain filter that decomposes backscatter into the (unwanted) high-pass component associated with bedform topography (ripples, dunes, and sand waves) and vegetation, and the (desired) low-frequency component associated with the composition of sediment patches superimposed on the topography. This process strengthens relationships between backscatter and sediment composition. A probabilistic framework is presented for classifying vegetated and unvegetated substrates based on acoustic backscatter at decimeter resolution. This capability is demonstrated using data collected from diverse settings within a 386 km reach of a canyon river whose bed varies among sand, gravel, cobbles, boulders, and submerged vegetation.

  13. Compositional signatures in acoustic backscatter over vegetated and unvegetated mixed sand-gravel riverbeds

    Science.gov (United States)

    Buscombe, Daniel; Grams, Paul E.; Kaplinski, Matt A.

    2017-01-01

    Multibeam acoustic backscatter has considerable utility for remote characterization of spatially heterogeneous bed sediment composition over vegetated and unvegetated riverbeds of mixed sand and gravel. However, the use of high-frequency, decimeter-resolution acoustic backscatter for sediment classification in shallow water is hampered by significant topographic contamination of the signal. In mixed sand-gravel riverbeds, changes in the abiotic composition of sediment (such as homogeneous sand to homogeneous gravel) tend to occur over larger spatial scales than is characteristic of small-scale bedform topography (ripples, dunes, and bars) or biota (such as vascular plants and periphyton). A two-stage method is proposed to filter out the morphological contributions to acoustic backscatter. First, the residual supragrain-scale topographic effects in acoustic backscatter with small instantaneous insonified areas, caused by ambiguity in the local (beam-to-beam) bed-sonar geometry, are removed. Then, coherent scales between high-resolution topography and backscatter are identified using cospectra, which are used to design a frequency domain filter that decomposes backscatter into the (unwanted) high-pass component associated with bedform topography (ripples, dunes, and sand waves) and vegetation, and the (desired) low-frequency component associated with the composition of sediment patches superimposed on the topography. This process strengthens relationships between backscatter and sediment composition. A probabilistic framework is presented for classifying vegetated and unvegetated substrates based on acoustic backscatter at decimeter resolution. This capability is demonstrated using data collected from diverse settings within a 386 km reach of a canyon river whose bed varies among sand, gravel, cobbles, boulders, and submerged vegetation.

  14. Restoration of mountain big sagebrush steppe following prescribed burning to control western juniper.

    Science.gov (United States)

    Davies, K W; Bates, J D; Madsen, M D; Nafus, A M

    2014-05-01

    Western juniper (Juniperus occidentalis ssp. occidentalis Hook) encroachment into mountain big sagebrush (Artemisia tridentata spp. vaseyana (Rydb.) Beetle) steppe has reduced livestock forage production, increased erosion risk, and degraded sagebrush-associated wildlife habitat. Western juniper has been successfully controlled with partial cutting followed by prescribed burning the next fall, but the herbaceous understory and sagebrush may be slow to recover. We evaluated the effectiveness of seeding perennial herbaceous vegetation and sagebrush at five sites where juniper was controlled by partially cutting and prescribed burning. Treatments tested at each site included an unseeded control, herbaceous seed mix (aerially seeded), and the herbaceous seed mix plus sagebrush seed. In the third year post-treatment, perennial grass cover and density were twice as high in plots receiving the herbaceous seed mix compared to the control plots. Sagebrush cover and density in the sagebrush seeded plots were between 74- and 290-fold and 62- and 155-fold greater than the other treatments. By the third year after treatment, sagebrush cover was as high as 12 % in the sagebrush seeded plots and between 0 % and 0.4 % where it was not seeded. These results indicate that aerial seeding perennial herbaceous vegetation can accelerate the recovery of perennial grasses which likely stabilize the site. Our results also suggest that seeding mountain big sagebrush after prescribed burning encroaching juniper can rapidly recover sagebrush cover and density. In areas where sagebrush habitat is limited, seeding sagebrush after juniper control may increase sagebrush habitat and decrease the risks to sagebrush-associated species.

  15. Developing the Guidelines for Reclamation to Forest Vegetation in the Athabasca Oil Sands Region

    Energy Technology Data Exchange (ETDEWEB)

    Straker, J. [Integral Ecology Group Ltd., Victoria, BC (Canada); Cumulative Environmental Management Association, Fort McMurray, AB (Canada). Reclamation Working Group, Terrestrial Subgroup; Donald, G. [Donald Functional and Applied Ecology Inc., Victoria, BC (Canada); Cumulative Environmental Management Association, Fort McMurray, AB (Canada). Reclamation Working Group, Terrestrial Subgroup

    2010-07-01

    This paper discussed the development process behind and the structure of the Guidelines for Reclamation to Forest Vegetation in the Athabasca Oil Sands Region. The advances present in the second edition, published in 2010, were described relative to the first edition, which was published in 1998. Oils sands mining companies are mandated to use the manual under the Alberta Environmental Protection and Enhancement Act. The paper provided an overview of the structure of the second edition and presented the process used to develop the second edition. It also described the planning approaches for revegetative treatments and the planning guidance of overstory and understory species selection. The methods for evaluating revegetative success were also described with particular reference to plant community composition and soil salinity indicators as examples of indicator development. The goal of the manual is to provide guidance on re-establishing the vegetation component of upland ecosystems on reclaimed landscapes and on evaluating the success of the re-establishment, assuming that the reclaimed plant communities should have species characteristic of native plant communities in the region, that the trends of vegetation community and structure development on reclaimed land should be similar to native plant communities in the region, and that the reclaimed ecosystems should have development trajectories that satisfy land-use objectives and provide resilience against natural disturbances. 15 refs., 1 tab., 1 fig.

  16. Historical fire regimes, reconstructed from land-survey data, led to complexity and fluctuation in sagebrush landscapes.

    Science.gov (United States)

    Bukowski, Beth E; Baker, William L

    2013-04-01

    Sagebrush landscapes provide habitat for Sage-Grouse and other sagebrush obligates, yet historical fire regimes and the structure of historical sagebrush landscapes are poorly known, hampering ecological restoration and management. To remedy this, General Land Office Survey (GLO) survey notes were used to reconstruct over two million hectares of historical vegetation for four sagebrush-dominated (Artemisia spp.) study areas in the western United States. Reconstructed vegetation was analyzed for fire indicators used to identify historical fires and reconstruct historical fire regimes. Historical fire-size distributions were inverse-J shaped, and one fire > 100 000 ha was identified. Historical fire rotations were estimated at 171-342 years for Wyoming big sagebrush (A. tridentata ssp. wyomingensis) and 137-217 years for mountain big sagebrush (A. tridentata ssp. vaseyana). Historical fire and patch sizes were significantly larger in Wyoming big sagebrush than mountain big sagebrush, and historical fire rotations were significantly longer in Wyoming big sagebrush than mountain big sagebrush. Historical fire rotations in Wyoming were longer than those in other study areas. Fine-scale mosaics of burned and unburned area and larger unburned inclusions within fire perimeters were less common than in modern fires. Historical sagebrush landscapes were dominated by large, contiguous areas of sagebrush, though large grass-dominated areas and finer-scale mosaics of grass and sagebrush were also present in smaller amounts. Variation in sagebrush density was a common source of patchiness, and areas classified as "dense" made up 24.5% of total sagebrush area, compared to 16.3% for "scattered" sagebrush. Results suggest significant differences in historical and modern fire regimes. Modern fire rotations in Wyoming big sagebrush are shorter than historical fire rotations. Results also suggest that historical sagebrush landscapes would have fluctuated, because of infrequent

  17. Effects of land cover and regional climate variations on long-term spatiotemporal changes in sagebrush ecosystems

    Science.gov (United States)

    Xian, George Z.; Homer, Collin G.; Aldridge, Cameron L.

    2012-01-01

    This research investigated the effects of climate and land cover change on variation in sagebrush ecosystems. We combined information of multi-year sagebrush distribution derived from multitemporal remote sensing imagery and climate data to study the variation patterns of sagebrush ecosystems under different potential disturbances. We found that less than 40% of sagebrush ecosystem changes involved abrupt changes directly caused by landscape transformations and over 60% of the variations involved gradual changes directly related to climatic perturbations. The primary increases in bare ground and declines in sagebrush vegetation abundance were significantly correlated with the 1996-2006 decreasing trend in annual precipitation.

  18. Surface energy exchanges over contrasting vegetation types on a subtropical sand island

    Science.gov (United States)

    Gray, Michael; McGowan, Hamish; Lowry, Andrew; Guyot, Adrien

    2017-04-01

    The surface energy balance of subtropical coastal vegetation communities has thus far received little attention. Here we present a multi-year observational data set using the eddy covariance method to quantify for the first time the surface energy balance over three contrasting vegetation types on a subtropical sand island in eastern Australia: a periodically inundated sedge swamp, an exotic pine plantation and a coastal heath. Maximum daily sensible heat flux varied between sites but was typically > 280 Wm-2 in the coastal heath and pine plantation but no more than 250 Wm-2 in the swamp when dry and 1. The partitioning of energy, as represented by β, is similar to a variety of Australian ecosystems, and a range of coastal vegetation types in other latitudes, but differs from other tropical or subtropical locations which have strongly seasonal rainfall patterns and therefore a switch from β > 1 before rainfall to β changes in background meteorology with the most important influences being net radiation, absolute humidity, and rainfall. The main factor differentiating the sites was soil water content, with the remnant coastal heath and swamp having ready access to water but the exotic pine plantation having much drier soils. Should the current balance between remnant vegetation and the pine plantation undergo changes there would be a corresponding shift in the surface energy balance of the island as a whole, and altered plant water use may lead to reduced water table depth, important because the groundwater of the local islands is used as part of a regional water grid. A better understanding of the response of coastal vegetation to atmospheric forcing will enable more informed decision making on land use changes, as coastal regions the world over face development pressure.

  19. Acid rock drainage passive remediation using alkaline clay and impacts of vegetation and saturated sand barrier

    Science.gov (United States)

    Plaza, F.; Wen, Y.; Liang, X.

    2017-12-01

    Acid rock drainage (ARD) caused by abundance of coal refuse (CR) deposits in mining regions requires adequate treatment to prevent serious water pollution due to its acidity and high concentrations of sulfate and metals/metalloids. Over the past decades, various approaches have been explored and developed to remediate ARD. This study uses laboratory experiments to investigate the effectiveness and impacts of ARD passive remediation using alkaline clay (AC), a by-product of the aluminum refining process. Twelve column kinetic leaching experiments were set up with CR/AC mixing ratios ranging from 1%AC to 10%AC. Samples were collected from these columns to measure the pH, sulfate, metals/metalloids, acidity and alkalinity. Additional tests of XRD and acid base accounting were also conducted to better characterize the mineral phase in terms of the alkalinity and acidity potential. Based on the leachate measurement results, these columns were further classified into two groups of neutral/near neutral pH and acidic pH for further analysis. In addition, impacts of the vegetation and saturated sand layer on the remediation effectiveness were explored. The results of our long-term (more than three years in some cases) laboratory experiments show that AC is an effective ARD remediation material for the neutralization of leachate pH and immobilization of sulfate and metals such as Fe, Mn, Cu, Zn, Ni, Pb, Cd, Co. The CR/AC mixing ratios higher than 3%AC are found to be effective, with 10% close to optimal. Moreover, the results demonstrate the benefits of using vegetation and a saturated sand barrier. Vegetation acted as a phytoaccumulation/phytoextraction agent, causing an additional immobilization of metals. The saturated sand barrier blocked the oxygen and water diffusion downwards, leading to a reduction of the pyrite oxidation rate. Finally, the proposed remediation approach shows that the acidity consumption will likely occur before all the alkalinity is exhausted

  20. Natural regeneration processes in big sagebrush (Artemisia tridentata)

    Science.gov (United States)

    Schlaepfer, Daniel R.; Lauenroth, William K.; Bradford, John B.

    2014-01-01

    Big sagebrush, Artemisia tridentata Nuttall (Asteraceae), is the dominant plant species of large portions of semiarid western North America. However, much of historical big sagebrush vegetation has been removed or modified. Thus, regeneration is recognized as an important component for land management. Limited knowledge about key regeneration processes, however, represents an obstacle to identifying successful management practices and to gaining greater insight into the consequences of increasing disturbance frequency and global change. Therefore, our objective is to synthesize knowledge about natural big sagebrush regeneration. We identified and characterized the controls of big sagebrush seed production, germination, and establishment. The largest knowledge gaps and associated research needs include quiescence and dormancy of embryos and seedlings; variation in seed production and germination percentages; wet-thermal time model of germination; responses to frost events (including freezing/thawing of soils), CO2 concentration, and nutrients in combination with water availability; suitability of microsite vs. site conditions; competitive ability as well as seedling growth responses; and differences among subspecies and ecoregions. Potential impacts of climate change on big sagebrush regeneration could include that temperature increases may not have a large direct influence on regeneration due to the broad temperature optimum for regeneration, whereas indirect effects could include selection for populations with less stringent seed dormancy. Drier conditions will have direct negative effects on germination and seedling survival and could also lead to lighter seeds, which lowers germination success further. The short seed dispersal distance of big sagebrush may limit its tracking of suitable climate; whereas, the low competitive ability of big sagebrush seedlings may limit successful competition with species that track climate. An improved understanding of the

  1. Ecological influence and pathways of land use in sagebrush

    Science.gov (United States)

    Knick, Steven T.; Hanser, Steven E.; Miller, Richard F.; Pyke, David A.; Wisdom, Michael J.; Finn, Sean P.; Rinkes, E. Thomas; Henny, Charles J.; Knick, Steven T.; Connelly, John W.

    2011-01-01

    Land use in sagebrush (Artemisia spp.) landscapes influences all sage-grouse (Centrocer-cus spp.) populations in western North America. Croplands and the network of irrigation canals cover 230,000 km2 and indirectly influence up to 77% of the Sage-Grouse Conservation Area and 73% of sagebrush land cover by subsidizing synanthropic predators on sage-grouse. Urbanization and the demands of human population growth have created an extensive network of con-necting infrastructure that is expanding its influence on sagebrush landscapes. Over 2,500 km2 are now covered by interstate highways and paved roads; when secondary roads are included, 15% of the Sage-Grouse Conservation Area and 5% of existing sagebrush habitats are 2.5 km from roads. Density of secondary roads often exceeds 5 km/km2, resulting in widespread motorized access for recreation, creating extensive travel corridors for management actions and resource development, subsidizing predators adapted to human presence, and facilitating spread of exotic or invasive plants. Sagebrush lands also are being used for their wilderness and recreation values, including off highway vehicle use. Approximately 12,000,000 animal use months (AUM amount of forage to support one livestock unit per month) are permitted for grazing livestock on public lands in the western states. Direct effects of grazing on sage-grouse populations or sagebrush landscapes are not possible to assess from current data. However, management of lands grazed by livestock has influenced sagebrush ecosystems by vegetation treatments to increase forage and reduce sagebrush and other plant species unpalatable to livestock. Fences (2 km/km2 in some regions), roads, and water developments to manage livestock movements further modify the landscape. Oil and gas development influences 8% of the sagebrush habitats with the highest intensities occurring in the eastern range of sage-grouse; 20% of the sagebrush distribution is indirectly influenced in the Great

  2. Impacts of Vegetation Growth on Reach-scale Flood Hydraulics in a Sand-bed River and the Implications for Vegetation-morphology Coevolution

    Science.gov (United States)

    Box, S.; Wilcox, A. C.

    2017-12-01

    Vegetation alters flood hydraulics and geomorphic response, yet quantifying and predicting such responses across spatial and temporal scales remains challenging. Plant- and patch-scale studies consistently show that vegetation increases local hydraulic variability, yet reach-scale hydrodynamic models often assume vegetation has a spatially homogeneous effect on hydraulics. Using Nays2DH in iRIC (International River Interface Cooperative), we model the effect of spatially heterogeneous vegetation on a series of floods with varying antecedent vegetation conditions in a sand-bed river in western Arizona, taking advantage of over a decade of data on a system that experienced substantial geomorphic, hydrologic, and ecosystem changes. We show that pioneer woody seedlings (Tamarix, Populus, Salix) and cattail (Typha) increase local hydraulic variability, including velocity and bed shear stress, along individual cross sections, predominantly by decreasing velocity in zones of vegetation establishment and growth and increasing velocity in unvegetated areas, with analogous effects on shear stress. This was especially prominent in a study reach where vegetation growth contributed to thalweg incision relative to a vegetated bar. Evaluation of these results in the context of observed geomorphic response to floods elucidates mechanisms by which vegetation and channel morphology coevolve at a reach scale. By quantifying the influence of spatially heterogeneous vegetation on reach-scale hydraulics, we demonstrate that plant- and patch-scale research on vegetation hydraulics is applicable to ecogeomorphology at the reach scale.

  3. Measuring splash erosion potential under vegetation using sand-filled splash cups

    Science.gov (United States)

    Geißler, C.; Scholten, T.; Kühn, P.

    2009-04-01

    In soil erosion research it is widely accepted that vegetation is not only protecting the soil from the erosive power of rainfall. Under specific circumstances (like they occur e.g. in forests) vegetation can enhance the erosive power of rainfall by modifying its properties (esp. drop size distribution, kinetic energy). The adjacent processes are very complex and variable in time and space and depend on numerous variables (e.g. rainfall intensity, drop size distribution, drop fall velocity, height of the canopy, density of the canopy, crown and leaf traits, LAI). In the last decades a large number of studies focused this process-system using different methods and came to often different results (Brandt 1989; Calder 2001; Foot & Morgan 2005; Hall & Calder 1993; Mosley 1982; Nanko et al. 2006; Park & Cameron 2008; Vis 1986). The main objective of our field experiments in subtropical China is to quantify the modification of precipitation by its pass through the canopy layer for six different tree species, three different successional stages and three different biodiversity classes. For this, new splash cups were developed based on the archetype of Ellison (1947). In contrast to previous studies with splash cups (Vis 1986) or other forms of splash cups (Kinnell 1974; Morgan 1981) we measured the unit sand remaining inside the cup after single natural rainfall events. The new splash cups contain of a PE-flask to which a carrier system has been attached. In this carrier system a cup filled with unit sand of 125-200 µm particle size is inserted. At the bottom of the cup a silk cover is attached to avoid the loss of sand and to guarantee free drainage of water from the cup to the carrier and vice versa. Cup and PE-flask are hydraulically connected by a cotton wick to assure constant moisture content throughout the time of measuring. Additionally, vents in the carrier system ensure that the pressure arising from the insertion of the cup doesn't lead to a loss of sand. The

  4. Seasonal Differences in Climatic Controls of Vegetation Growth in the Beijing-Tianjin Sand Source Region of China.

    Science.gov (United States)

    Wang, H.

    2017-12-01

    Seasonal differences in climatic controls of vegetation growth in the Beijing-Tianjin Sand Source Region of China Bin He1 , Haiyan Wan11 State Key Laboratory of Earth Surface Processes and Resource Ecology, College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China Corresponding author: Bin He, email addresses: hebin@bnu.edu.cnPhone:+861058806506, Address: Beijing Normal University, College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China. Email addresses of co-authors: wanghaiyan@mail.bnu.edu.cnABSTRACTLaunched in 2000, the Beiing-Tainjin Sand Source Controlling Project (BTSSCP) is an ecological restoration project intended to prevent desertification in China. Evidence from multiple sources has confirmed increases in vegetation growth in the BTSSCP region since the initiation of the project. Precipitation and related soil moisture conditions typically are considered to be the main drivers of vegetation growth in this arid region. However, by investigating the relationships between vegetation growth and corresponding climatic factors, we identified seasonal variation in the climatic constraints of vegetation growth. In spring, vegetation growth is stimulated mainly by elevated temperature, whereas precipitation is the lead driver of summer greening. In autumn, positive effects of both temperature and precipitation on vegetation growth were observed. Furthermore, strong biosphere-atmosphere interactions were observed in this region. Spring warming promotes vegetation growth, but also reduces soil moisture. Summer greening has a strong cooling effect on land surface temperature. These results indicate that 1) precipitation-based projections of vegetation growth may be misleading; and 2) the ecological and environment consequences of ecological projects should be comprehensively evaluated. KEYWORDS: vegetation growth, climatic drivers, seasonal variation, BTSSCP

  5. Characterization and Ecophysiological Observations on Coastal Sand Dune Vegetation from Goa, Central West Coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Rodrigues, R.S.

    Coastal Sand Dune flora (CSD) forms a specialized group of plants commonly referred as psammophytes. Goa has limited natural resources including beaches and sand dunes. The state is globally known for its tourism activities, which pressurize...

  6. Conversion of sagebrush shrublands to exotic annual grasslands negatively impacts small mammal communities

    Science.gov (United States)

    Ostoja, S.M.; Schupp, E.W.

    2009-01-01

    Aim The exotic annual cheatgrass (Bromus tectorum) is fast replacing sagebrush (Artemisia tridentata) communities throughout the Great Basin Desert and nearby regions in the Western United States, impacting native plant communities and altering fire regimes, which contributes to the long-term persistence of this weedy species. The effect of this conversion on native faunal communities remains largely unexamined. We assess the impact of conversion from native perennial to exotic annual plant communities on desert rodent communities. Location Wyoming big sagebrush shrublands and nearby sites previously converted to cheatgrass-dominated annual grasslands in the Great Basin Desert, Utah, USA. Methods At two sites in Tooele County, Utah, USA, we investigated with Sherman live trapping whether intact sagebrush vegetation and nearby converted Bromus tectorum-dominated vegetation differed in rodent abundance, diversity and community composition. Results Rodent abundance and species richness were considerably greater in sagebrush plots than in cheatgrass-dominated plots. Nine species were captured in sagebrush plots; five of these were also trapped in cheatgrass plots, all at lower abundances than in the sagebrush. In contrast, cheatgrass-dominated plots had no species that were not found in sagebrush. In addition, the site that had been converted to cheatgrass longer had lower abundances of rodents than the site more recently converted to cheatgrass-dominated plots. Despite large differences in abundances and species richness, Simpson's D diversity and Shannon-Wiener diversity and Brillouin evenness indices did not differ between sagebrush and cheatgrass-dominated plots. Main conclusions This survey of rodent communities in native sagebrush and in converted cheatgrass-dominated vegetation suggests that the abundances and community composition of rodents may be shifting, potentially at the larger spatial scale of the entire Great Basin, where cheatgrass continues to invade

  7. Soil-vegetation relationships and community structure in a "terra-firme"-white-sand vegetation gradient in Viruá National Park, northern Amazon, Brazil.

    Science.gov (United States)

    Mendonça, Bruno A F DE; Fernandes, Elpídio I; Schaefer, Carlos E G R; Mendonça, Júlia G F DE; Vasconcelos, Bruno N F

    2017-01-01

    Viruá National Park encompasses a vast and complex system of hydromorphic sandy soils covered largely by the white sand vegetation ("Campinarana") ecosystem. The purpose of this study was to investigate a vegetation gradient of "terra-firme"-white sand vegetation at the Viruá National Park. Nine plots representing three physiognomic units were installed for floristic and phytosociological surveys as well as to collect composite soil samples. The data were subjected to assessments of floristic diversity and similarity, phytosociological parameters and to statistical analyses, focused on principal components (PC) and canonical correspondence analysis (CCA). The vegetation of the Campinaranas types and Forest differed in biomass and species density. Ten species, endemic to Brazil, were particularly well-represented. PC and CCA indicated a clear distinction between the studied plots, based on measured soil variables, especially base sum and clay, which were the most differentiating properties between Campinarana and Forest; For the separation of the Campinarana types, the main distinguishing variable was organic matter content and cation exchange capacity. Higher similarity of Campinaranas was associated to a monodominant species and the lower similarity of Forest was related to the high occurrence of locally rare species.

  8. Size distributions and dispersions along a 485-year chronosequence for sand dune vegetation.

    Science.gov (United States)

    Waugh, Jennifer M; Aarssen, Lonnie W

    2012-04-01

    Using a sand dune chronosequence that spans 485 years of primary succession, we collected nearest-neighbor vegetation data to test two predictions associated with the traditional "size-advantage" hypothesis for plant competitive ability: (1) the relative representation of larger species should increase in later stages of succession; and (2) resident species that are near neighbors should, over successional time, become more similar in plant body size and/or seed size than expected by random assembly. The first prediction was supported over the time period between mid to later succession, but the second prediction was not; that is, there was no temporal pattern across the chronosequence indicating that either larger resident species, or larger seeded resident species, increasingly exclude smaller ones from local neighborhoods over time. Rather, neighboring species were generally more different from each other in seed sizes than expected by random assembly. As larger species accumulate over time, some relatively small species are lost from later stages of succession, but species size distributions nevertheless remain strongly right-skewed-even in late succession-and species of disparate sizes are just as likely as in early succession to coexist as immediate neighbors. This local-scale coexistence of disparate sized neighbors might be accounted for-as in traditional interpretations-in terms of species differences in "physical-space-niches" (e.g., involving different rooting depths), combined with possible facilitation effects. We propose, however, that this coexistence may also occur because competitive ability involves more than just a size advantage, with traits associated with survival (tolerance of intense competition) and fecundity (offspring production despite intense competition) being at least equally important.

  9. Remote sensing of sagebrush canopy nitrogen

    Science.gov (United States)

    Mitchell, Jessica J.; Glenn, Nancy F.; Sankey, Temuulen T.; Derryberry, DeWayne R.; Germino, Matthew J.

    2012-01-01

    This paper presents a combination of techniques suitable for remotely sensing foliar Nitrogen (N) in semiarid shrublands – a capability that would significantly improve our limited understanding of vegetation functionality in dryland ecosystems. The ability to estimate foliar N distributions across arid and semi-arid environments could help answer process-driven questions related to topics such as controls on canopy photosynthesis, the influence of N on carbon cycling behavior, nutrient pulse dynamics, and post-fire recovery. Our study determined that further exploration into estimating sagebrush canopy N concentrations from an airborne platform is warranted, despite remote sensing challenges inherent to open canopy systems. Hyperspectral data transformed using standard derivative analysis were capable of quantifying sagebrush canopy N concentrations using partial least squares (PLS) regression with an R2 value of 0.72 and an R2 predicted value of 0.42 (n = 35). Subsetting the dataset to minimize the influence of bare ground (n = 19) increased R2 to 0.95 (R2 predicted = 0.56). Ground-based estimates of canopy N using leaf mass per unit area measurements (LMA) yielded consistently better model fits than ground-based estimates of canopy N using cover and height measurements. The LMA approach is likely a method that could be extended to other semiarid shrublands. Overall, the results of this study are encouraging for future landscape scale N estimates and represent an important step in addressing the confounding influence of bare ground, which we found to be a major influence on predictions of sagebrush canopy N from an airborne platform.

  10. Acid rock drainage passive remediation using alkaline clay: Hydro-geochemical study and impacts of vegetation and sand on remediation.

    Science.gov (United States)

    Plaza, Fernando; Wen, Yipei; Liang, Xu

    2018-10-01

    Acid rock drainage (ARD) is one of the most adverse environmental problems of the mine industry, especially in regions with an abundance of coal refuse (CR) deposits (e.g. the Northern Appalachian Coalfield in the USA) where surface and ground waters are affected by this pollution due to the acidity and high content of sulfates and heavy metals. This study explores the effectiveness of the ARD passive remediation method using alkaline clay (AC) through a series of static and long-term kinetic laboratory experiments (over three years) complemented with field measurements and geochemical modeling. Two important issues associated with this passive and auto-sustainable ARD remediation method were investigated: 1) the hydrogeochemical study of the mixture in terms of the percentages of AC and CR, and, 2) impacts of vegetation cover and a saturated sand barrier on the remediation. Both the field measurements and the samples used for the experiments came from a local coal waste site. Through the analysis of the field measurements and the outcome of the laboratory experiments and the geochemical modeling, alkaline clay proved to be an effective remediation material for ARD, in terms of achieving a neutral pH in the leachate and immobilization of sulfate and metals such as Fe, Mn, Cu, Zn, Ni, Pb, Cd, Co. Moreover, it has been demonstrated that the use of vegetation and a saturated sand barrier are beneficial. Vegetation acted as a phytoaccumulation/phytoextraction agent, causing an additional immobilization of metals. The saturated sand barrier blocked downward the oxygen and water diffusion, reducing pyrite oxidation rates. The proposed remediation approach ensures that the acidity consumption will likely occur before all the alkalinity is exhausted. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Managing Vegetation on Peat-Sand Filter Beds for Wastewater Disposal

    Science.gov (United States)

    Arthur E. Elling

    1985-01-01

    Five species of grass, one sedge, and cattail were grown on a peat-sand filter bed irrigated with sewage effluent. Yields, uptake of nitrogen and phosphorus, and lodging problems were determined for all species when grown to various heights ranging from 5 to 75 cm.

  12. Interaction of petroleum mulching, vegetation restoration and dust fallout on the conditions of sand dunes in southwest of Iran

    Science.gov (United States)

    Azoogh, Liela; Khalili moghadam, Bijan; Jafari, Siroos

    2018-06-01

    In the past half-century, petroleum mulching-biological fixation (PM-BF) practices have been employed to stabilize sand dunes in Iran. However, the effects of PM-BF practices on the attributes of sand dunes and the dispersion of heavy metals of mulch have been poorly understood. To this end, three regions treated with PM-BF for 5, 20, and 40 years and a control region with no PM-BF were studied. Samples of soil properties were taken at the depths of 0-10 cm and 10-50 cm, with three replications, in Khuzestan Province. The results showed that PM-BF practices promoted the restoration of vegetation cover in the sand dunes. In addition, these practices increased the deposition of dust particles, gradually increasing the magnitudes of palygorskite and smectite clays over time. The interactions between dust deposition and PM-BF practices significantly altered the chemical and physical properties of the dunes. PM-BF practices increased soil organic matter (184-287%), cation exchangeable capacity (142-209%), electrical conductivity (144-493%), clay content (134-196%), and penetration resistance (107-170%) compared to the region with no PM-BF practices. Furthermore, petroleum mulching significantly increased the amount of Ni (1.19%), Cd (1.55%), Pb (1.08%), Cu (1.34%), Zn (1.38%), Mn (1.66%), and Fe (1.15%). However, in the long term, these elements will probably leach linearly as a consequence of an increase in organic matter and soil salinity in the light texture of sand dunes.

  13. Multiscale sagebrush rangeland habitat modeling in the Gunnison Basin of Colorado

    Science.gov (United States)

    Homer, Collin G.; Aldridge, Cameron L.; Meyer, Debra K.; Schell, Spencer J.

    2013-01-01

    ). Results were validated with an independent accuracy assessment, with root mean square error values ranging from 3.5 (percent big sagebrush) to 10.8 (percent bare ground) at the QuickBird scale, and from 4.5 (percent Wyoming sagebrush) to 12.4 (percent herbaceous) at the full Landsat scale. These results offer significant improvement in sagebrush ecosystem quantification across the Gunnison Basin, and also provide maximum flexibility to users to employ for a wide variety of applications. Further refinement of these remote sensing component predictions in the future will be most likely achieved by focusing on more extensive ground plot sampling, employing new high and moderate-resolution satellite sensors that offer additional spectral bands for vegetation discrimination, and capturing more dates of satellite imagery to better represent phenological variation.

  14. UV-induced carbon monoxide emission from sand and living vegetation

    DEFF Research Database (Denmark)

    Bruhn, Dan; Albert, Kristian Rost; Mikkelsen, Teis Nørgaard

    2012-01-01

    The global burden of carbon monoxide, CO, is rather uncertain. In this paper we address the potential of UV-induced CO emission by terrestrial surfaces. Real-time measurements of [CO] were made with a cavity enhanced laser connected in closed loop to either an ecosystem chamber or a leaf scale...... chamber. Sand and leaves of all examined plant species exhibited emission of CO in response to artificial UV-radiation and the UV-component of natural solar radiation. The UV-induced rate of CO emission exhibited a rather low dependence on temperature, indicating an abiotic process. The emission of CO...... in response to the UV-component of natural solar radiation was also evident at the ecosystem scale. When scaled to the global level, the UV-induced emission of CO by the major types of terrestrial surfaces, living leaves and soil (here represented by sand), amounts up to 28 Tg yr−1. This source has...

  15. Arbuscular mycorrhizal fungi associated with psammophilic vegetation in Mediterranean coastal sand dunes

    Energy Technology Data Exchange (ETDEWEB)

    Camprubi, A.; Calvet, C.; Cabot, P.; Pitet, M.; Estaun, V.

    2010-07-01

    This study was conducted in order to characterize the natural albacore's mycorrhizal (AM) biodiversity from Mediterranean sand dune ecosystems and to protect in a collection this biodiversity. The occurrence of AM fungi associated with sand dune plant species in three Mediterranean locations on the north-eastern coast of Spain was examined in one well preserved coastal sand dune and in two embrionary dunes recently protected from public access. Traditional taxonomy and molecular techniques were used to identify the AM fungal species present in these ecosystems. The species identified and isolated were: Scutellospora persica (Kiosk and Walker) Walker and Sanders, Glomus ambisporum Smith and Schenck, Glomus diaphanum Morton and Walker, Glomus clarum Nicolson and Schenck, Glomus intraradices Schenck and Smith, Glomus microaggregatum Koske, Gemma and Olexia and Gigaspora margarita Becker and Hall. Spores of Glomus were the most abundant in the direct soil extraction samples. The molecular analysis indicates that the most abundant fungi forming AM in the roots belonged to the Gigasporaceae group followed by fungi of Glomus group A and Glomus group B. The highest diversity of fungi and abundance of the AM fungal spores was found in the well preserved and undisturbed dune systems. (Author) 26 refs.

  16. Banking Wyoming big sagebrush seeds

    Science.gov (United States)

    Robert P. Karrfalt; Nancy Shaw

    2013-01-01

    Five commercially produced seed lots of Wyoming big sagebrush (Artemisia tridentata Nutt. var. wyomingensis (Beetle & Young) S.L. Welsh [Asteraceae]) were stored under various conditions for 5 y. Purity, moisture content as measured by equilibrium relative humidity, and storage temperature were all important factors to successful seed storage. Our results indicate...

  17. Common raven occurrence in relation to energy transmission line corridors transiting human-altered sagebrush steppe

    Science.gov (United States)

    Coates, Peter S.; Howe, Kristy B.; Casazza, Michael L.; Delehanty, David J.

    2014-01-01

    Energy-related infrastructure and other human enterprises within sagebrush steppe of the American West often results in changes that promote common raven (Corvus corax; hereafter, raven) populations. Ravens, a generalist predator capable of behavioral innovation, present a threat to many species of conservation concern. We evaluate the effects of detailed features of an altered landscape on the probability of raven occurrence using extensive raven survey (n= 1045) and mapping data from southern Idaho, USA. We found nonlinear relationships between raven occurrence and distances to transmission lines, roads, and facilities. Most importantly, raven occurrence was greater with presence of transmission lines up to 2.2 km from the corridor.We further explain variation in raven occurrence along anthropogenic features based on the amount of non-native vegetation and cover type edge, such that ravens select fragmented sagebrush stands with patchy, exotic vegetative introgression. Raven occurrence also increased with greater length of edge formed by the contact of big sagebrush (Artemisia tridentate spp.) with non-native vegetation cover types. In consideration of increasing alteration of sagebrush steppe, these findings will be useful for planning energy transmission corridor placement and other management activities where conservation of sagebrush obligate species is a priority.

  18. Carbon sequestration capacity of shifting sand dune after establishing new vegetation in the Tengger Desert, northern China.

    Science.gov (United States)

    Yang, Haotian; Li, Xinrong; Wang, Zengru; Jia, Rongliang; Liu, Lichao; Chen, Yongle; Wei, Yongping; Gao, Yanhong; Li, Gang

    2014-04-15

    Reconstructing vegetation in arid and semiarid areas has become an increasingly important management strategy to realize habitat recovery, mitigate desertification and global climate change. To assess the carbon sequestration potential in areas where sand-binding vegetation has been established on shifting sand dunes by planting xeric shrubs located near the southeastern edge of the Tengger Desert in northern China, we conducted a field investigation of restored dune regions that were established at different times (20, 30, 47, and 55 years ago) in the same area. We quantified the total organic carbon (TOC) in each ecosystem by summing the individual carbon contributions from the soil (soil organic carbon; SOC), shrubs, and grasses in each system. We found that the TOC, as well as the amount of organic carbon in the soil, shrubs, and grasses, significantly increased over time in the restored areas. The average annual rate of carbon sequestration was highest in the first 20 years after restoration (3.26 × 10(-2)kg·m(-2) ·year(-1)), and reached a stable rate (2.14 × 10(-2) kg·m(-2) ·year(-1)) after 47 years. Organic carbon storage in soil represented the largest carbon pool for both restored systems and a system containing native vegetation, accounting for 67.6%-85.0% of the TOC. Carbon in grass root biomass, aboveground grass biomass, litter, aboveground shrub biomass, and shrub root biomass account for 10.0%-21.0%, 0.2%-0.6%, 0.1%-0.2%, 1.7%-12.1% and 0.9%-6.2% of the TOC, respectively. Furthermore, we found that the 55-year-old restored system has the capacity to accumulate more TOC (1.02 kg·m(-2) more) to reach the TOC level found in the natural vegetation system. These results suggest that restoring desert ecosystems may be a cost-effective and environmentally friendly way to sequester CO2 from the atmosphere and mitigate the effects of global climate change. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Scaling of Sediment Dynamics in a Reach-Scale Laboratory Model of a Sand-Bed Stream with Riparian Vegetation

    Science.gov (United States)

    Gorrick, S.; Rodriguez, J. F.

    2011-12-01

    A movable bed physical model was designed in a laboratory flume to simulate both bed and suspended load transport in a mildly sinuous sand-bed stream. Model simulations investigated the impact of different vegetation arrangements along the outer bank to evaluate rehabilitation options. Preserving similitude in the 1:16 laboratory model was very important. In this presentation the scaling approach, as well as the successes and challenges of the strategy are outlined. Firstly a near-bankfull flow event was chosen for laboratory simulation. In nature, bankfull events at the field site deposit new in-channel features but cause only small amounts of bank erosion. Thus the fixed banks in the model were not a drastic simplification. Next, and as in other studies, the flow velocity and turbulence measurements were collected in separate fixed bed experiments. The scaling of flow in these experiments was simply maintained by matching the Froude number and roughness levels. The subsequent movable bed experiments were then conducted under similar hydrodynamic conditions. In nature, the sand-bed stream is fairly typical; in high flows most sediment transport occurs in suspension and migrating dunes cover the bed. To achieve similar dynamics in the model equivalent values of the dimensionless bed shear stress and the particle Reynolds number were important. Close values of the two dimensionless numbers were achieved with lightweight sediments (R=0.3) including coal and apricot pips with a particle size distribution similar to that of the field site. Overall the moveable bed experiments were able to replicate the dominant sediment dynamics present in the stream during a bankfull flow and yielded relevant information for the analysis of the effects of riparian vegetation. There was a potential conflict in the strategy, in that grain roughness was exaggerated with respect to nature. The advantage of this strategy is that although grain roughness is exaggerated, the similarity of

  20. Sagebrush ecosystems: current status and trends.

    Science.gov (United States)

    Beever, E.A.; Connelly, J.W.; Knick, S.T.; Schroeder, M.A.; Stiver, S. J.

    2004-01-01

    The sagebrush (Artemisia spp.) biome has changed since settlement by Europeans. The current distribution, composition and dynamics, and disturbance regimes of sagebrush ecosystems have been altered by interactions among disturbance, land use, and invasion of exotic plants. In this chapter, we present the dominant factors that have influenced habitats across the sagebrush biome. Using a large-scale analysis, we identified regional changes and patterns in “natural disturbance”, invasive exotic species, and influences of land use in sagebrush systems. Number of fires and total area burned has increased since 1980 across much of the sagebrush biome. Juniper (Juniperus spp.) and pinyon (Pinus spp.) woodlands have expanded into sagebrush habitats at higher elevations. Cheatgrass (Bromus tectorum), an exotic annual grass, has invaded much of lower elevation, more xeric sagebrush landscapes across the western portion of the biome. Consequently, synergistic feedbacks between habitats and disturbance (natural and human-caused) have altered disturbance regimes, plant community dynamics and contributed to loss of sagebrush habitats and change in plant communities. Habitat conversion to agriculture has occurred in the highly productive regions of the sagebrush biome and influenced up to 56% of the Conservation Assessment area. Similarly, urban areas, and road, railroad, and powerline networks fragment habitats, facilitate predator movements, and provide corridors for spread of exotic species across the entire sagebrush biome. Livestock grazing has altered sagebrush habitats; the effects of overgrazing combined with drought on plant communities in the late 1880s and early 1900s still influences current habitats. Management of livestock grazing has influenced sagebrush ecosystems by habitat treatments to increase forage and reduce sagebrush and other plant species unpalatable to livestock. Fences, roads, and water developments to manage livestock movements have further

  1. Two centuries of vegetation succession in an inland sand dune area, central Netherlands

    Czech Academy of Sciences Publication Activity Database

    Ujházy, K.; Fanta, J.; Prach, Karel

    2011-01-01

    Roč. 14, č. 3 (2011), 316-325 ISSN 1402-2001 R&D Projects: GA ČR(CZ) GAP505/11/0256 Institutional research plan: CEZ:AV0Z60050516 Keywords : primary succession * relief types * vegetation mapping Subject RIV: EH - Ecology, Behaviour Impact factor: 1.678, year: 2011

  2. Ecological restoration and recovery in the wind-blown sand hazard areas of northern China: relationship between soil water and carrying capacity for vegetation in the Tengger Desert.

    Science.gov (United States)

    Li, XingRong; Zhang, ZhiShan; Tan, HuiJuan; Gao, YanHong; Liu, LiChao; Wang, XingPing

    2014-05-01

    The main prevention and control area for wind-blown sand hazards in northern China is about 320000 km(2) in size and includes sandlands to the east of the Helan Mountain and sandy deserts and desert-steppe transitional regions to the west of the Helan Mountain. Vegetation recovery and restoration is an important and effective approach for constraining wind-blown sand hazards in these areas. After more than 50 years of long-term ecological studies in the Shapotou region of the Tengger Desert, we found that revegetation changed the hydrological processes of the original sand dune system through the utilization and space-time redistribution of soil water. The spatiotemporal dynamics of soil water was significantly related to the dynamics of the replanted vegetation for a given regional precipitation condition. The long-term changes in hydrological processes in desert areas also drive replanted vegetation succession. The soil water carrying capacity of vegetation and the model for sand fixation by revegetation in aeolian desert areas where precipitation levels are less than 200 mm are also discussed.

  3. The impact of an increasing elephant population on the woody vegetation in southern Sabi Sand Wildtuin, South Africa

    Directory of Open Access Journals (Sweden)

    Kay Hiscocks

    1999-07-01

    Full Text Available In 1961, a fence was erected between privately owned Sabi Sand Wildtuin (SSW and the Kruger National Park (KNP, which largely prevented elephants entering the SSW. In 1993, the fence was removed. This lead to a rapid influx of elephants into the SSW during the winter months, most of which move back into the KNP during the wet summer season. In 1993, the SSW elephant population was 1/1045 ha but increased to 1/305.8 ha in 1996. It more than doubled to 1/146 ha in 1998. This study was undertaken on the property Kingston, in southern SSW, to assess the impact of elephants on woody vegetation and determine why they show seasonal dietary preferences for specific tree parts. Vegetation utilisation was recorded on a five kilometer transect of vehicle track in 1996 and repeated in 1998. From the transect, species density was calculated for those trees impacted on. Trees that had been newly bark stripped were recorded in 1996 and 1998. Cambium samples were collected in summer and winter from eight tree species. Field observations of elephants impacting on woody vegetation augmented the data base. Transect analysis showed a strong correlation between tree utilisation and density. The most visual damage was of Combretum apiculatum, Acacia burkei, Pterocarpus rotundifolius and Grewia species. Tree damage increased by 73 from 1996 to 1998. Significantly higher levels of nitrogen, sodium and magnesium were found in the species most regularly bark stripped. Bull elephants were responsible for 94 of the trees seen uprooted. The results suggested that SSW can sustain the present elephant population, but further influx at the present rate of increase, will have a negative impact on the reserve.

  4. Effects of disturbance on vegetation by sand accretion and erosion across coastal dune habitats on a barrier island.

    Science.gov (United States)

    Miller, Thomas E

    2015-01-12

    Coastal geomorphology and vegetation are expected to be particularly sensitive to climate change, because of disturbances caused by sea-level rise and increased storm frequency. Dunes have critical reciprocal interactions with vegetation; dunes create habitats for plants, while plants help to build dunes and promote geomorphological stability. These interactions are also greatly affected by disturbances associated with sand movement, either in accretion (dune building) or in erosion. The magnitude and intensity of disturbances are expected to vary with habitat, from the more exposed and less stable foredunes, to low-lying and flood-prone interdunes, to the protected and older backdunes. Permanent plots were established at three different spatial scales on St George Island, FL, USA, where the vegetation and dune elevation were quantified annually from 2011 to 2013. Change in elevation, either through accretion or erosion, was used as a measure of year-to-year disturbance over the 2 years of the study. At the scale of different dune habitats, foredunes were found to have the greatest disturbance, while interdunes had the least. Elevation and habitat (i.e. foredune, interdune, backdune) were significantly correlated with plant community composition. Generalized linear models conducted within each habitat show that the change in elevation (disturbance) is also significantly correlated with the plant community, but only within foredunes and interdunes. The importance of disturbance in exposed foredunes was expected and was found to be related to an increasing abundance of a dominant species (Uniola paniculata) in eroding areas. The significant effect of disturbance in the relatively stable interdunes was surprising, and may be due to the importance of flooding associated with small changes in elevation in these low-lying areas. Overall, this study documents changes in the plant community associated with elevation, and demonstrates that the foredune and interdune

  5. Big and black sagebrush landscapes [Chapter 5

    Science.gov (United States)

    Stanley G. Kitchen; E. Durant McArthur

    2007-01-01

    Perhaps no plant evokes a common vision of the semi-arid landscapes of western North America as do the sagebrushes. A collective term, sagebrush is applied to shrubby members of the mostly herbaceous genus, Artemisia L. More precisely, the moniker is usually restricted to members of subgenus Tridentatae, a collection of some 20 woody taxa endemic to North America (...

  6. Ecohydrology of adjacent sagebrush and lodgepole pine ecosystems: the consequences of climate change and disturbance

    Science.gov (United States)

    Bradford, John B.; Schlaepfer, Daniel R.; Lauenroth, William K.

    2014-01-01

    Sagebrush steppe and lodgepole pine forests are two of the most widespread vegetation types in the western United States and they play crucial roles in the hydrologic cycle of these water-limited regions. We used a process-based ecosystem water model to characterize the potential impact of climate change and disturbance (wildfire and beetle mortality) on water cycling in adjacent sagebrush and lodgepole pine ecosystems. Despite similar climatic and topographic conditions between these ecosystems at the sites examined, lodgepole pine, and sagebrush exhibited consistent differences in water balance, notably more evaporation and drier summer soils in the sagebrush and greater transpiration and less water yield in lodgepole pine. Canopy disturbances (either fire or beetle) have dramatic impacts on water balance and availability: reducing transpiration while increasing evaporation and water yield. Results suggest that climate change may reduce snowpack, increase evaporation and transpiration, and lengthen the duration of dry soil conditions in the summer, but may have uncertain effects on drainage. Changes in the distribution of sagebrush and lodgepole pine ecosystems as a consequence of climate change and/or altered disturbance regimes will likely alter ecosystem water balance.

  7. Resilience and resistance of sagebrush ecosystems: implications for state and transition models and management treatments

    Science.gov (United States)

    Chambers, Jeanne C.; Miller, Richard F.; Board, David I.; Pyke, David A.; Roundy, Bruce A.; Grace, James B.; Schupp, Eugene W.; Tausch, Robin J.

    2014-01-01

    In sagebrush ecosystems invasion of annual exotics and expansion of piñon (Pinus monophylla Torr. and Frem.) and juniper (Juniperus occidentalis Hook., J. osteosperma [Torr.] Little) are altering fire regimes and resulting in large-scale ecosystem transformations. Management treatments aim to increase resilience to disturbance and enhance resistance to invasive species by reducing woody fuels and increasing native perennial herbaceous species. We used Sagebrush Steppe Treatment Evaluation Project data to test predictions on effects of fire vs. mechanical treatments on resilience and resistance for three site types exhibiting cheatgrass (Bromus tectorum L.) invasion and/or piñon and juniper expansion: 1) warm and dry Wyoming big sagebrush (WY shrub); 2) warm and moist Wyoming big sagebrush (WY PJ); and 3) cool and moist mountain big sagebrush (Mtn PJ). Warm and dry (mesic/aridic) WY shrub sites had lower resilience to fire (less shrub recruitment and native perennial herbaceous response) than cooler and moister (frigid/xeric) WY PJ and Mtn PJ sites. Warm (mesic) WY Shrub and WY PJ sites had lower resistance to annual exotics than cool (frigid to cool frigid) Mtn PJ sites. In WY shrub, fire and sagebrush mowing had similar effects on shrub cover and, thus, on perennial native herbaceous and exotic cover. In WY PJ and Mtn PJ, effects were greater for fire than cut-and-leave treatments and with high tree cover in general because most woody vegetation was removed increasing resources for other functional groups. In WY shrub, about 20% pretreatment perennial native herb cover was necessary to prevent increases in exotics after treatment. Cooler and moister WY PJ and especially Mtn PJ were more resistant to annual exotics, but perennial native herb cover was still required for site recovery. We use our results to develop state and transition models that illustrate how resilience and resistance influence vegetation dynamics and management options.

  8. [Storages and distributed patterns of soil organic carbon and total nitrogen during the succession of artificial sand-binding vegetation in arid desert ecosystem].

    Science.gov (United States)

    Jia, Xiao-Hong; Li, Xin-Rong; Zhou, Yu-Yan; Li, Yuan-Shou

    2012-03-01

    Soil carbon pool acts as the largest one of carbon pools in the terrestrial ecosystem. The storages and distributed patterns of soil organic carbon (SOC) and total nitrogen (TN) evaluated accurately are helpful to predict the feedback between the terrestrial ecosystem and climate changes. Based on the data about bulk density, content of SOC and TN at 0-100 cm soil profile, the density of SOC and TN at the temporal (chronosequence of artificial vegetation) and spatial (vertical) distributed patterns have been estimated. The results indicated that storages of SOC and TN at 0-100 cm depth increased with the chronosequence of artificial vegetation. The storages of SOC and TN showed the same tendency with the succession time of artificial vegetation. Storages of SOC and TN significantly increased at the early stage of banding sand by artificially vegetation ( 25 a). The variation of storages mainly occurred in the 0-20 cm depth. The storages decreased with the soil vertical depth. At the early stage of banding sand, increase in storage included every depth (0-100 cm). Whereas, at the later stage, increase in storage at 0-20 cm depth was main, and increase in the 20-100 cm was inconspicuous. The accumulation of storage at the shallow soil depth was more notability with the succession of artificial vegetation. The distributed pattern of storage in SOC and TN has been confirmed in arid desert regions below 200 mm annual precipitation. This was beneficial to understand the carbon cycle and to predict the feedback relationship between desert ecosystem and climate changes.

  9. The effect of herbaceous species removal, fire and cheatgrass (Bromus tectorum) on soil water availability in sagebrush steppe

    Science.gov (United States)

    Alison Whittaker; Bruce Roundy; Jeanne Chambers; Susan Meyer; Robert Blank; Stanley Kitchen; John Korfmacher

    2008-01-01

    Over the past several decades, cheatgrass (Bromus tectorum) has been continually expanding in the sagebrush steppe ecosystem. There has been very little research that examines why cheatgrass is able to invade these communities. To determine the effects of herbaceous vegetation removal and fire on available water for cheatgrass invasion, as well as...

  10. Assessing long-term variations in sagebrush habitat: characterization of spatial extents and distribution patterns using multi-temporal satellite remote-sensing data

    Science.gov (United States)

    Xian, George; Homer, Collin G.; Aldridge, Cameron L.

    2012-01-01

    An approach that can generate sagebrush habitat change estimates for monitoring large-area sagebrush ecosystems has been developed and tested in southwestern Wyoming, USA. This prototype method uses a satellite-based image change detection algorithm and regression models to estimate sub-pixel percentage cover for five sagebrush habitat components: bare ground, herbaceous, litter, sagebrush and shrub. Landsat images from three different months in 1988, 1996 and 2006 were selected to identify potential landscape change during these time periods using change vector (CV) analysis incorporated with an image normalization algorithm. Regression tree (RT) models were used to estimate percentage cover for five components on all change areas identified in 1988 and 1996, using unchanged 2006 baseline data as training for both estimates. Over the entire study area (24 950 km2), a net increase of 98.83 km2, or 0.7%, for bare ground was measured between 1988 and 2006. Over the same period, the other four components had net losses of 20.17 km2, or 0.6%, for herbaceous vegetation; 30.16 km2, or 0.7%, for litter; 32.81 km2, or 1.5%, for sagebrush; and 33.34 km2, or 1.2%, for shrubs. The overall accuracy for shrub vegetation change between 1988 and 2006 was 89.56%. Change patterns within sagebrush habitat components differ spatially and quantitatively from each other, potentially indicating unique responses by these components to disturbances imposed upon them.

  11. Vegetation development in a sand dune ten years after restoration, Parque Municipal das Dunas da Lagoa da Conceição, Florianópolis, Santa Catarina

    Directory of Open Access Journals (Sweden)

    Nina Rosa Zanin Zanella

    2010-01-01

    Full Text Available The vegetation cover of a sand dune was surveyed ten years after the improvement of a restoration project that utilized seed sowing, seedling planting and seedling transplantation from an adjacent area with watering in the first months. On the upper part of the restored dune, the vegetation was sparse (53% but more developed than that of the adjacent control area (34%, both presenting herbaceous/subshrub physiognomy with predominance of Panicum racemosum. On the slope of the restored dune, a shrub vegetation developed, presenting a percentage cover (90% similar to that of the control area (100%. Dodonaea viscosa was the dominant species on this restored face. The establishment of arboreal and shrub species seedlings on the upper dune was good. In part, this improved the species richness, but contributed to dissimilarity between this area and the control site.  A lower species richness was presented on the slope and the similarity to the control area was even lower. Plants introduced by sowing and seedling transplantation showed success and contributed to the similarity with the adjacent vegetation. Seedlings of arboreal and shrub plants survived on the upper dune. These species are represented in a more developed stage of succession, differing from the adjacent control area.

  12. Crop type influences edge effects on the reproduction of songbirds in sagebrush habitat near agriculture

    Directory of Open Access Journals (Sweden)

    Elly C. Knight

    2014-06-01

    Full Text Available Extensive fragmentation of the sagebrush shrubsteppe of western North America could be contributing to observed population declines of songbirds in sagebrush habitat. We examined whether habitat fragmentation impacts the reproduction of songbirds in sagebrush edge habitat near agriculture, and if potential impacts vary depending on the adjacent crop type. Specifically, we evaluated whether nest abundance and nest survival varied between orchard edge habitat, vineyard edge habitat, and interior habitat. We then examined whether the local nest predator community and vegetation could explain the differences detected. We detected fewer nests in edge than interior habitat. Nest abundance per songbird was also lower in edge than interior habitat, although only adjacent to vineyards. Nest predation was more frequent in orchard edge habitat than vineyard edge or interior habitat. Predators identified with nest cameras were primarily snakes, however, reduced nest survival in orchard edge habitat was not explained by differences in the abundance of snakes or any other predator species identified. Information theoretic analysis of daily survival rates showed that greater study plot shrub cover and lower grass height at nests were partially responsible for the lower rate of predation-specific daily nest survival rate (PDSR observed in orchard edge habitat, but additional factors are likely important. Results of this study suggest that different crop types have different edge effects on songbirds nesting in sagebrush shrubsteppe, and that these reproductive edge effects may contribute to observed declines of these species. Habitat managers should avoid the creation of new orchard-sagebrush habitat edges to avoid further impacts on already declining songbird populations.

  13. Vegetation types and forest productivity, west part of Syncrude's Lease 17, Alberta. Environmental Research Monography 1977-6. [Tar sands

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, E B; Levinsohn, A G

    1977-01-01

    The vegetation that existed in August 1977 on the western half of Syncrude's Lease 17 near Fort McMurray, Alberta is described. Eight vegetation types were identified and are mapped at a scale if 1 : 24,000. Black Spruce--Labrador Tea was the dominant vegetation type, making up 35.0% of the 9250 hectare study area. The second most abundant vegetation type was Aspen--White Spruce (26.0%) and the third was White Spruce--Aspen (18.0%). The remaining 21.0% of the area was occupied by the Aspen--Birch vegetation type (7.5%), Balsam Poplar--Alder (6.0%) along the McKay River, Sedge--Reed Grass (4.0%) mainly around bodies of standing water created by beaver dams, Willow--Reed Grass (3.0%) along stream courses, and Black Spruce--Feathermoss (0.5%). The White Spruce--Aspen type is best developed in the southern part of the lease. It is the only vegetation type that contains some white spruce stands approaching the present lower limits of merchantable forest in Alberta. The Aspen--White Spruce type was less productive. In terms of mean annual increment and site index, the two vegetation types with the greatest potential for fibre production (White Spruce--Aspen and Aspen--White Spruce types) are average or below average productivity when compared to data from similar stands elsewhere in Alberta and Saskatchewan.

  14. Fine-scale patterns of vegetation assembly in the monitoring of changes in coastal sand-dune landscapes

    Directory of Open Access Journals (Sweden)

    J. Honrado

    2010-02-01

    Full Text Available Understanding dune ecosystem responses to multi-scale environmental changes can provide the framework for reliable forecasts and cost-efficient protocols for detecting shifts in prevailing coastal dynamics. Based on the hypothesis that stress and disturbance interact as primary community controls in coastal dunes, we studied the fine-scale floristic assembly of foredune vegetation, in its relation to topography, along regional and local environmental gradients in the 200 km long coastline of northern Portugal, encompassing a major biogeographic transition in western Europe. Thirty topographic profiles perpendicular to the shoreline were recorded at ten sites along the regional climate gradient, and vegetation was sampled by recording the frequency of plant species along those profiles. Quantitative topographic attributes of vegetated dune profiles (e.g. length or height exhibited wide variations relatable to differences in prevailing coastal dynamics. Metrics of taxonomic diversity (e.g. total species richness and its additive beta component and of the functional composition of vegetation were highly correlated to attributes of dune topography. Under transgressive dynamics, vegetation profiles have fewer species, increased dominance, lower turnover rates, and lower total vegetation cover. These changes may drive a decrease in structural and functional diversity, with important consequences for resistance, resilience and other ecosystem properties. Moreover, differences in both vegetation assembly (in meta-stable dunes and response to increased disturbance (in eroding dunes between distinct biogeographic contexts highlight a possible decline in facilitation efficiency under extreme physical stress (i.e. under Mediterranean climate and support the significance of functional approaches in the study of local ecosystem responses to disturbance along regional gradients. Our results strongly suggest that assessing fine-scale community assembly can

  15. Feedbacks among Floods, Pioneer Woody Vegetation, and Channel Change in Sand-Bed Rivers: Insights from Field Studies of Controlled Flood Releases and Models

    Science.gov (United States)

    Wilcox, A. C.; Shafroth, P. B.; Lightbody, A.; Stella, J. C.; Bywater-Reyes, S.; Kiu, L.; Skorko, K.

    2012-04-01

    To investigate feedbacks between flow, geomorphic processes, and pioneer riparian vegetation in sand-bed rivers, we are combining field, hydraulic modeling, and laboratory simulations. Field studies have examined the response of woody riparian seedlings and channel morphology to prescribed dam-released floods that have been designed in part to maintain a native riparian woodland system on the Bill Williams River, Arizona, USA. Through monitoring of floods over a 7-year period, we have observed temporal and spatial variations in channel response. Floods have produced geomorphic and vegetation responses that varied with distance downstream of a dam, with scour and associated seedling mortality closer to the dam and aggradation and burial-induced mortality in a downstream reach with greater sediment supply. We also have observed that as vegetation grows beyond the seedling stage, its stabilizing effect on bars and its drag effect on flow progressively increases, such that floods of similar sizes but at different times may produce markedly different downstream responses as a function of vegetation characteristics. We also observed greater mortality among nonnative Tamarix spp. (tamarisk) seedlings than among native Salix gooddingii (Goodding's willow) seedlings, likely as a result of the greater first-year growth of willow relative to tamarisk. Combining field observations with modeling predictions of local hydraulics for the flood events we have studied is being used to draw linkages between hydraulics, channel change, and plant response at the patch and bar scale. In addition, mechanistic linkages are being examined using a field-scale laboratory stream channel, where seedlings of Tamarix spp. (tamarisk) and Populus fremontii (cottonwood) were planted and subjected to floods with varying sediment feed rate and plant configurations. The floods conveyed by our model channel were generally insufficient to scour the woody seedlings we planted, but changes in bar size and

  16. Shelter Index and a simple wind speed parameter to characterize vegetation control of sand transport threshold and Flu

    Science.gov (United States)

    Gillies, J. A.; Nield, J. M.; Nickling, W. G.; Furtak-Cole, E.

    2014-12-01

    Wind erosion and dust emissions occur in many dryland environments from a range of surfaces with different types and amounts of vegetation. Understanding how vegetation modulates these processes remains a research challenge. Here we present results from a study that examines the relationship between an index of shelter (SI=distance from a point to the nearest upwind vegetation/vegetation height) and particle threshold expressed as the ratio of wind speed measured at 0.45 times the mean plant height divided by the wind speed at 17 m when saltation commences, and saltation flux. The results are used to evaluate SI as a parameter to characterize the influence of vegetation on local winds and sediment transport conditions. Wind speed, wind direction, saltation activity and point saltation flux were measured at 35 locations in defined test areas (~13,000 m2) in two vegetation communities: mature streets of mesquite covered nebkhas and incipient nebkhas dominated by low mesquite plants. Measurement positions represent the most open areas, and hence those places most susceptible to wind erosion among the vegetation elements. Shelter index was calculated for each measurement position for each 10° wind direction bin using digital elevation models for each site acquired using terrestrial laser scanning. SI can show the susceptibility to wind erosion at different time scales, i.e., event, seasonal, or annual, but in a supply-limited system it can fail to define actual flux amounts due to a lack of knowledge of the distribution of sediment across the surface of interest with respect to the patterns of SI.

  17. Uptake and kinetics of 226Ra, 210Pb and 210Po in big sagebrush

    International Nuclear Information System (INIS)

    Simon, S.L.

    1985-01-01

    Root uptake of 226 Ra, 210 Pb and 210 Po by mature sagebrush was studied using a soil injection method for spiking the soil with minimal root disturbance. The main objective was to measure vegetation concentrations and determine concentration ratios (CR's) due to root uptake as a function of time in mature big sagebrush. Concentration ratios obtained in mature vegetation and in steady-state situations may be valuable in assessing the impact of uranium mining and milling. The vegetation was sampled approximately every 3 months for a 2 year period. Significant levels of activity were detected in the vegetation beginning at the first sampling (81 days after soil injection for 226 Ra, 28 days for 210 Pb and 210 Po). There was an exponential decrease in concentration to an apparent steady-state value. Mean values (geometric) of the data pooled over the second year period indicated that the steady-state CR's for 226 Ra, 210 Pb and 210 Po, as determined in mature sagebrush, were 0.04, 0.009, and 0.08, respectively. A three compartment mathematical model was formulated to help understand mechanisms of plant uptake and to predict, if possible, the concentration of 226 Ra, 210 Pb and 210 Po in vegetation as a function of time after soil spiking. A numerical solution was determined by 'calibrating' the general model solution with constants determined from regressions of concentrations in vegetation, soil leaching and leaf leaching data. Validation of the model is currently not possible because of an absence of similar time-dependent uptake studies. 168 refs., 19 figs., 18 tabs

  18. Changes in vegetation and biological soil crust communities on sand dunes stabilizing after a century of grazing on San Miguel Island, Channel Island National Park, California

    Science.gov (United States)

    Zellman, Kristine L.

    2014-01-01

    San Miguel Island is the westernmost of the California Channel Islands and one of the windiest areas on the west coast of North America. The majority of the island is covered by coastal sand dunes, which were stripped of vegetation and subsequently mobilized due to droughts and sheep ranching during the late 19th century and early 20th century. Since the removal of grazing animals, vegetation and biological soil crusts have once again stabilized many of the island's dunes. In this study, historical aerial photographs and field surveys were used to develop a chronosequence of the pattern of change in vegetation communities and biological soil crust levels of development (LOD) along a gradient of dune stabilization. Historical aerial photographs from 1929, 1954, 1977, and 2009 were georeferenced and used to delineate changes in vegetation canopy cover and active (unvegetated) dune extent among 5 historical periods (pre-1929, 1929–1954, 1954–1977, 1977–2009, and 2009–2011). During fieldwork, vegetation and biological soil crust communities were mapped along transects distributed throughout San Miguel Island's central dune field on land forms that had stabilized during the 5 time periods of interest. Analyses in a geographic information system (GIS) quantified the pattern of changes that vegetation and biological soil crust communities have exhibited on the San Miguel Island dunes over the past 80 years. Results revealed that a continuing increase in total vegetation cover and a complex pattern of change in vegetation communities have taken place on the San Miguel Island dunes since the removal of grazing animals. The highly specialized native vascular vegetation (sea rocket, dunedelion, beach-bur, and locoweed) are the pioneer stabilizers of the dunes. This pioneer community is replaced in later stages by communities that are dominated by native shrubs (coastal goldenbush, silver lupine, coyote-brush, and giant coreopsis), with apparently overlapping or

  19. Nitrogen deposition and soil carbon content affect nitrogen mineralization during primary succession in acid inland drift sand vegetation

    NARCIS (Netherlands)

    Sparrius, L.B.; Kooijman, A.M.

    2013-01-01

    Background and aims Two inland dunes in the Netherlands receiving low (24) and high (41 kg N ha−1 yr−1) nitrogen (N) deposition were compared for N dynamics and microbial activity to investigate the potential effect of N on succession rate of the vegetation and loss of pioneer habitats. Methods

  20. Evaluation of Turf-Grass and Prairie-Vegetated Rain Gardens in a Clay and Sand Soil, Madison, Wisconsin, Water Years 2004-08

    Science.gov (United States)

    Selbig, William R.; Balster, Nicholas

    2010-01-01

    The U.S. Geological Survey, in cooperation with a consortium of 19 cities, towns, and villages in Dane County, Wis., undertook a study to compare the capability of rain gardens with different vegetative species and soil types to infiltrate stormwater runoff from the roof of an adjacent structure. Two rain gardens, one planted with turf grass and the other with native prairie species, were constructed side-by-side in 2003 at two locations with different dominant soil types, either sand or clay. Each rain garden was sized to a ratio of approximately 5:1 contributing area to receiving area and to a depth of 0.5 foot. Each rain garden, regardless of vegetation or soil type, was capable of storing and infiltrating most of the runoff over the 5-year study period. Both rain gardens in sand, as well as the prairie rain garden in clay, retained and infiltrated 100 percent of all precipitation and snowmelt events during water years 2004-07. The turf rain garden in clay occasionally had runoff exceed its confining boundaries, but was still able to retain 96 percent of all precipitation and snowmelt events during the same time period. Precipitation intensity and number of antecedent dry days were important variables that influenced when the storage capacity of underlying soils would become saturated, which resulted in pooled water in the rain gardens. Because the rooftop area that drained runoff to each rain garden was approximately five times larger than the area of the rain garden itself, evapotranspiration was a small percentage of the annual water budget. For example, during water year 2005, the maximum evapotranspiration of total influent volume ranged from 21 percent for the turf rain garden in clay to 25 percent for the turf rain garden in sand, and the minimum ranged from 12 percent for the prairie rain garden in clay to 19 percent for the prairie rain garden in sand. Little to no runoff left each rain garden as effluent and a small percentage of runoff returned to the

  1. Comparison of radionuclide levels in soil, sagebrush, plant litter, cryptogams, and small mammals

    International Nuclear Information System (INIS)

    Landeen, D.S.

    1994-09-01

    Soil, sagebrush, plant litter, cryptogam, and small mammal samples were collected and analyzed for cesium-137, strontium-90, plutonium-238, plutonium 239/240, technetium-99, and iodine-129 from 1981 to 1986 at the US Department of Energy Hanford Site in southeastern Washington State as part of site characterization and environmental monitoring activities. Samples were collected on the 200 Areas Plateau, downwind from ongoing waste management activities. Plant litter, cryptogams, and small mammals are media that are not routinely utilized in monitoring or characterization efforts for determination of radionuclide concentrations. Studies at Hanford, other US Department of Energy sites, and in eastern Europe have indicated that plant litter and cryptogams may serve as effective ''natural'' monitors of air quality. Plant litter in this study consists of fallen leaves from sagebrush and ''cryptogams'' describes that portion of the soil crust composed of mosses, lichens, algae, and fungi. Comparisons of cesium-137 and strontium-90 concentrations in the soil, sagebrush, litter, and cryptogams revealed significantly higher (p<0.05) levels in plant litter and cryptogams. Technetium-99 values were the highest in sagebrush and litter. Plutonium-238 and 239/40 and iodine-129 concentrations never exceeded 0.8 pCi/gm in all media. No evidence of any significant amounts of any radionuclides being incorporated into the small mammal community was discovered. The data indicate that plant litter and cryptogams may be better, indicators of environmental quality than soil or vegetation samples. Augmenting a monitoring program with samples of litter and cryptogams may provide a more accurate representation of radionuclide environmental uptake and/or contamination levels in surrounding ecosystems. The results of this study may be applied directly to other radioecological monitoring conducted at other nuclear sites and to the monitoring of other pollutants

  2. Forecasting sagebrush ecosystem components and greater sage-grouse habitat for 2050: learning from past climate patterns and Landsat imagery to predict the future

    Science.gov (United States)

    Homer, Collin G.; Xian, George Z.; Aldridge, Cameron L.; Meyer, Debra K.; Loveland, Thomas R.; O'Donnell, Michael S.

    2015-01-01

    Sagebrush (Artemisia spp.) ecosystems constitute the largest single North American shrub ecosystem and provide vital ecological, hydrological, biological, agricultural, and recreational ecosystem services. Disturbances have altered and reduced this ecosystem historically, but climate change may ultimately represent the greatest future risk. Improved ways to quantify, monitor, and predict climate-driven gradual change in this ecosystem is vital to its future management. We examined the annual change of Daymet precipitation (daily gridded climate data) and five remote sensing ecosystem sagebrush vegetation and soil components (bare ground, herbaceous, litter, sagebrush, and shrub) from 1984 to 2011 in southwestern Wyoming. Bare ground displayed an increasing trend in abundance over time, and herbaceous, litter, shrub, and sagebrush showed a decreasing trend. Total precipitation amounts show a downward trend during the same period. We established statistically significant correlations between each sagebrush component and historical precipitation records using a simple least squares linear regression. Using the historical relationship between sagebrush component abundance and precipitation in a linear model, we forecasted the abundance of the sagebrush components in 2050 using Intergovernmental Panel on Climate Change (IPCC) precipitation scenarios A1B and A2. Bare ground was the only component that increased under both future scenarios, with a net increase of 48.98 km2 (1.1%) across the study area under the A1B scenario and 41.15 km2 (0.9%) under the A2 scenario. The remaining components decreased under both future scenarios: litter had the highest net reductions with 49.82 km2 (4.1%) under A1B and 50.8 km2 (4.2%) under A2, and herbaceous had the smallest net reductions with 39.95 km2 (3.8%) under A1B and 40.59 km2 (3.3%) under A2. We applied the 2050 forecast sagebrush component values to contemporary (circa 2006) greater sage-grouse (Centrocercus

  3. Primary successions of vegetation on technogenic sand patches in oil and gas producing districts of the middle Ob' river basin

    Energy Technology Data Exchange (ETDEWEB)

    Shilova, I I

    1977-11-01

    Intensive economic exploitation of the natural resources of the oil-and-gas producing districts of the central Ob' basin has led to increased exposure of sandy patches over the landscape. These sandy areas are becoming a common site. Technogenic factors involved include, for example, construction projects, oil-drilling and the like. Exposure is accelerated by wind and water erosion. Efforts are underway to reintroduce verdure in the region, and a study has been underway of the features of the ecotope and the stages of natural overgrowth of the area of reclamation. This overgrowth is proceeding well. Vegetation is of the syngenetic succession type, involving four successive stages and formation of associations of a zonal character. Seventy-four species of yeast, 2 species of fungi, 2 of lichens, 19 of Bryophyton and 106 of vascular spore- and covered-seed plants of the area have been recorded, and are tabulated. Recultivation will require due attention to existing conditions. 14 references.

  4. Vegetation

    DEFF Research Database (Denmark)

    Epstein, H.E.; Walker, D.A.; Bhatt, U.S.

    2012-01-01

    increased 20-26%. • Increasing shrub growth and range extension throughout the Low Arctic are related to winter and early growing season temperature increases. Growth of other tundra plant types, including graminoids and forbs, is increasing, while growth of mosses and lichens is decreasing. • Increases...... in vegetation (including shrub tundra expansion) and thunderstorm activity, each a result of Arctic warming, have created conditions that favor a more active Arctic fire regime....

  5. Sagebrush-ungulate relationships on the Northern Yellowstone Winter Range

    Science.gov (United States)

    Carl L. Wambolt

    2005-01-01

    Sagebrush (Artemisia) taxa have historically been the landscape dominants over much of the Northern Yellowstone Winter Range (NYWR). Their importance to the unnaturally large ungulate populations on the NYWR throughout the twentieth century has been recognized since the 1920s. Sagebrush-herbivore ecology has been the focus of research on the NYWR for...

  6. Effect of fungicides on Wyoming big sagebrush seed germination

    Science.gov (United States)

    Robert D. Cox; Lance H. Kosberg; Nancy L. Shaw; Stuart P. Hardegree

    2011-01-01

    Germination tests of Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle & Young [Asteraceae]) seeds often exhibit fungal contamination, but the use of fungicides should be avoided because fungicides may artificially inhibit germination. We tested the effect of seed-applied fungicides on germination of Wyoming big sagebrush at 2 different...

  7. A synopsis of short-term response to alternative restoration treatments in sagebrush-steppe: the SageSTEP project

    Science.gov (United States)

    McIver, James; Brunson, Mark; Bunting, Steve; Chambers, Jeanne; Doescher, Paul; Grace, James; Hulet, April; Johnson, Dale; Knick, Steven T.; Miller, Richard; Pellant, Mike; Pierson, Fred; Pyke, David; Rau, Benjamin; Rollins, Kim; Roundy, Bruce; Schupp, Eugene; Tausch, Robin; Williams, Jason

    2014-01-01

    The Sagebrush Steppe Treatment Evaluation Project (SageSTEP) is an integrated long-term study that evaluates ecological effects of alternative treatments designed to reduce woody fuels and to stimulate the herbaceous understory of sagebrush steppe communities of the Intermountain West. This synopsis summarizes results through 3 yr posttreatment. Woody vegetation reduction by prescribed fire, mechanical treatments, or herbicides initiated a cascade of effects, beginning with increased availability of nitrogen and soil water, followed by increased growth of herbaceous vegetation. Response of butterflies and magnitudes of runoff and erosion closely followed herbaceous vegetation recovery. Effects on shrubs, biological soil crust, tree cover, surface woody fuel loads, and sagebrush-obligate bird communities will take longer to be fully expressed. In the short term, cool wet sites were more resilient than warm dry sites, and resistance was mostly dependent on pretreatment herbaceous cover. At least 10 yr of posttreatment time will likely be necessary to determine outcomes for most sites. Mechanical treatments did not serve as surrogates for prescribed fire in how each influenced the fuel bed, the soil, erosion, and sage-obligate bird communities. Woody vegetation reduction by any means resulted in increased availability of soil water, higher herbaceous cover, and greater butterfly numbers. We identified several trade-offs (desirable outcomes for some variables, undesirable for others), involving most components of the study system. Trade-offs are inevitable when managing complex natural systems, and they underline the importance of asking questions about the whole system when developing management objectives. Substantial spatial and temporal heterogeneity in sagebrush steppe ecosystems emphasizes the point that there will rarely be a “recipe” for choosing management actions on any specific area. Use of a consistent evaluation process linked to monitoring may be the

  8. Spatial variability in cost and success of revegetation in a Wyoming big sagebrush community.

    Science.gov (United States)

    Boyd, Chad S; Davies, Kirk W

    2012-09-01

    The ecological integrity of the Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle and A. Young) alliance is being severely interrupted by post-fire invasion of non-native annual grasses. To curtail this invasion, successful post-fire revegetation of perennial grasses is required. Environmental factors impacting post-fire restoration success vary across space within the Wyoming big sagebrush alliance; however, most restorative management practices are applied uniformly. Our objectives were to define probability of revegetation success over space using relevant soil-related environmental factors, use this information to model cost of successful revegetation and compare the importance of vegetation competition and soil factors to revegetation success. We studied a burned Wyoming big sagebrush landscape in southeast Oregon that was reseeded with perennial grasses. We collected soil and vegetation data at plots spaced at 30 m intervals along a 1.5 km transect in the first two years post-burn. Plots were classified as successful (>5 seedlings/m(2)) or unsuccessful based on density of seeded species. Using logistic regression we found that abundance of competing vegetation correctly predicted revegetation success on 51 % of plots, and soil-related variables correctly predicted revegetation performance on 82.4 % of plots. Revegetation estimates varied from $167.06 to $43,033.94/ha across the 1.5 km transect based on probability of success, but were more homogenous at larger scales. Our experimental protocol provides managers with a technique to identify important environmental drivers of restoration success and this process will be of value for spatially allocating logistical and capital expenditures in a variable restoration environment.

  9. Seed bank and big sagebrush plant community composition in a range margin for big sagebrush

    Science.gov (United States)

    Martyn, Trace E.; Bradford, John B.; Schlaepfer, Daniel R.; Burke, Ingrid C.; Laurenroth, William K.

    2016-01-01

    The potential influence of seed bank composition on range shifts of species due to climate change is unclear. Seed banks can provide a means of both species persistence in an area and local range expansion in the case of increasing habitat suitability, as may occur under future climate change. However, a mismatch between the seed bank and the established plant community may represent an obstacle to persistence and expansion. In big sagebrush (Artemisia tridentata) plant communities in Montana, USA, we compared the seed bank to the established plant community. There was less than a 20% similarity in the relative abundance of species between the established plant community and the seed bank. This difference was primarily driven by an overrepresentation of native annual forbs and an underrepresentation of big sagebrush in the seed bank compared to the established plant community. Even though we expect an increase in habitat suitability for big sagebrush under future climate conditions at our sites, the current mismatch between the plant community and the seed bank could impede big sagebrush range expansion into increasingly suitable habitat in the future.

  10. Restoration of areas degraded by alluvial sand mining: use of soil microbiological activity and plant biomass growth to assess evolution of restored riparian vegetation.

    Science.gov (United States)

    Venson, Graziela R; Marenzi, Rosemeri C; Almeida, Tito César M; Deschamps-Schmidt, Alexandre; Testolin, Renan C; Rörig, Leonardo R; Radetski, Claudemir M

    2017-03-01

    River or alluvial sand mining is causing a variety of environmental problems in the Itajaí-açú river basin in Santa Catarina State (south of Brazil). When this type of commercial activity degrades areas around rivers, environmental restoration programs need to be executed. In this context, the aim of this study was to assess the evolution of a restored riparian forest based on data on the soil microbial activity and plant biomass growth. A reference site and three sites with soil degradation were studied over a 3-year period. Five campaigns were performed to determine the hydrolysis of the soil enzyme fluorescein diacetate (FDA), and the biomass productivity was determined at the end of the studied period. The variation in the enzyme activity for the different campaigns at each site was low, but this parameter did differ significantly according to the site. Well-managed sites showed the highest biomass productivity, and this, in turn, showed a strong positive correlation with soil enzyme activity. In conclusion, soil enzyme activity could form the basis for monitoring and the early prediction of the success of vegetal restoration programs, since responses at the higher level of biological organization take longer, inhibiting the assessment of the project within an acceptable time frame.

  11. Multiscale sagebrush rangeland habitat modeling in southwest Wyoming

    Science.gov (United States)

    Homer, Collin G.; Aldridge, Cameron L.; Meyer, Debra K.; Coan, Michael J.; Bowen, Zachary H.

    2009-01-01

    Sagebrush-steppe ecosystems in North America have experienced dramatic elimination and degradation since European settlement. As a result, sagebrush-steppe dependent species have experienced drastic range contractions and population declines. Coordinated ecosystem-wide research, integrated with monitoring and management activities, would improve the ability to maintain existing sagebrush habitats. However, current data only identify resource availability locally, with rigorous spatial tools and models that accurately model and map sagebrush habitats over large areas still unavailable. Here we report on an effort to produce a rigorous large-area sagebrush-habitat classification and inventory with statistically validated products and estimates of precision in the State of Wyoming. This research employs a combination of significant new tools, including (1) modeling sagebrush rangeland as a series of independent continuous field components that can be combined and customized by any user at multiple spatial scales; (2) collecting ground-measured plot data on 2.4-meter imagery in the same season the satellite imagery is acquired; (3) effective modeling of ground-measured data on 2.4-meter imagery to maximize subsequent extrapolation; (4) acquiring multiple seasons (spring, summer, and fall) of an additional two spatial scales of imagery (30 meter and 56 meter) for optimal large-area modeling; (5) using regression tree classification technology that optimizes data mining of multiple image dates, ratios, and bands with ancillary data to extrapolate ground training data to coarser resolution sensors; and (6) employing rigorous accuracy assessment of model predictions to enable users to understand the inherent uncertainties. First-phase results modeled eight rangeland components (four primary targets and four secondary targets) as continuous field predictions. The primary targets included percent bare ground, percent herbaceousness, percent shrub, and percent litter. The

  12. Mercury distribution in two Sierran forest and one desert sagebrush steppe ecosystems and the effects of fire

    International Nuclear Information System (INIS)

    Engle, Mark A.; Sexauer Gustin, Mae; Johnson, Dale W.; Murphy, James F.; Miller, Wally W.; Walker, Roger F.; Wright, Joan; Markee, Melissa

    2006-01-01

    Mercury (Hg) concentration, reservoir mass, and Hg reservoir size were determined for vegetation components, litter, and mineral soil for two Sierran forest sites and one desert sagebrush steppe site. Mercury was found to be held primarily in the mineral soil (maximum depth of 60 to 100 cm), which contained more than 90% of the total ecosystem reservoir. However, Hg in foliage, bark, and litter plays a more dominant role in Hg cycling than the mineral soil. Mercury partitioning into ecosystem components at the Sierran forest sites was similar to that observed for other US forest sites. Vegetation and litter Hg reservoirs were significantly smaller in the sagebrush steppe system because of lower biomass. Data collected from these ecosystems after wildfire and prescribed burns showed a significant decrease in the Hg pool from certain reservoirs. No loss from mineral soil was observed for the study areas but data from fire severity points suggested that Hg in the upper few millimeters of surface soil may be volatilized due to exposure to elevated temperatures. Comparison of data from burned and unburned plots suggested that the only significant source of atmospheric Hg from the prescribed burn was combustion of litter. Differences in unburned versus burned Hg reservoirs at the forest wildfire site demonstrated that drastic reduction in the litter and above ground live biomass Hg reservoirs after burning had occurred. Sagebrush and litter were absent in the burned plots after a wildfire suggesting that both reservoirs were released during the fire. Mercury emissions due to fire from the forest prescribed burn, forest wildfire, and sagebrush steppe wildfire sites were roughly estimated at 2.0 to 5.1, 2.2 to 4.9, and 0.36 ± 0.13 g ha -1 , respectively, with litter and vegetation being the most important sources

  13. A conservation paradox in the Great Basin—Altering sagebrush landscapes with fuel breaks to reduce habitat loss from wildfire

    Science.gov (United States)

    Shinneman, Douglas J.; Aldridge, Cameron L.; Coates, Peter S.; Germino, Matthew J.; Pilliod, David S.; Vaillant, Nicole M.

    2018-03-15

    Interactions between fire and nonnative, annual plant species (that is, “the grass/fire cycle”) represent one of the greatest threats to sagebrush (Artemisia spp.) ecosystems and associated wildlife, including the greater sage-grouse (Centrocercus urophasianus). In 2015, U.S. Department of the Interior called for a “science-based strategy to reduce the threat of large-scale rangeland fire to habitat for the greater sage-grouse and the sagebrush-steppe ecosystem.” An associated guidance document, the “Integrated Rangeland Fire Management Strategy Actionable Science Plan,” identified fuel breaks as high priority areas for scientific research. Fuel breaks are intended to reduce fire size and frequency, and potentially they can compartmentalize wildfire spatial distribution in a landscape. Fuel breaks are designed to reduce flame length, fireline intensity, and rates of fire spread in order to enhance firefighter access, improve response times, and provide safe and strategic anchor points for wildland fire-fighting activities. To accomplish these objectives, fuel breaks disrupt fuel continuity, reduce fuel accumulation, and (or) increase plants with high moisture content through the removal or modification of vegetation in strategically placed strips or blocks of land.Fuel breaks are being newly constructed, enhanced, or proposed across large areas of the Great Basin to reduce wildfire risk and to protect remaining sagebrush ecosystems (including greater sage-grouse habitat). These projects are likely to result in thousands of linear miles of fuel breaks that will have direct ecological effects across hundreds of thousands of acres through habitat loss and conversion. These projects may also affect millions of acres indirectly because of edge effects and habitat fragmentation created by networks of fuel breaks. Hence, land managers are often faced with a potentially paradoxical situation: the need to substantially alter sagebrush habitats with fuel breaks

  14. Investigating Seed Longevity of Big Sagebrush (Artemisia tridentata)

    Science.gov (United States)

    Wijayratne, Upekala C.; Pyke, David A.

    2009-01-01

    The Intermountain West is dominated by big sagebrush communities (Artemisia tridentata subspecies) that provide habitat and forage for wildlife, prevent erosion, and are economically important to recreation and livestock industries. The two most prominent subspecies of big sagebrush in this region are Wyoming big sagebrush (A. t. ssp. wyomingensis) and mountain big sagebrush (A. t. ssp. vaseyana). Increased understanding of seed bank dynamics will assist with sustainable management and persistence of sagebrush communities. For example, mountain big sagebrush may be subjected to shorter fire return intervals and prescribed fire is a tool used often to rejuvenate stands and reduce tree (Juniperus sp. or Pinus sp.) encroachment into these communities. A persistent seed bank for mountain big sagebrush would be advantageous under these circumstances. Laboratory germination trials indicate that seed dormancy in big sagebrush may be habitat-specific, with collections from colder sites being more dormant. Our objective was to investigate seed longevity of both subspecies by evaluating viability of seeds in the field with a seed retrieval experiment and sampling for seeds in situ. We chose six study sites for each subspecies. These sites were dispersed across eastern Oregon, southern Idaho, northwestern Utah, and eastern Nevada. Ninety-six polyester mesh bags, each containing 100 seeds of a subspecies, were placed at each site during November 2006. Seed bags were placed in three locations: (1) at the soil surface above litter, (2) on the soil surface beneath litter, and (3) 3 cm below the soil surface to determine whether dormancy is affected by continued darkness or environmental conditions. Subsets of seeds were examined in April and November in both 2007 and 2008 to determine seed viability dynamics. Seed bank samples were taken at each site, separated into litter and soil fractions, and assessed for number of germinable seeds in a greenhouse. Community composition data

  15. Fontainebleau Sand

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    2006-01-01

    The report is a summary of results from laboratory tests in the geotechncial research group on Fontainebleau sand.......The report is a summary of results from laboratory tests in the geotechncial research group on Fontainebleau sand....

  16. A cross-scale approach to understand drought-induced variability of sagebrush ecosystem productivity

    Science.gov (United States)

    Assal, T.; Anderson, P. J.

    2016-12-01

    Sagebrush (Artemisia spp.) mortality has recently been reported in the Upper Green River Basin (Wyoming, USA) of the sagebrush steppe of western North America. Numerous causes have been suggested, but recent drought (2012-13) is the likely mechanism of mortality in this water-limited ecosystem which provides critical habitat for many species of wildlife. An understanding of the variability in patterns of productivity with respect to climate is essential to exploit landscape scale remote sensing for detection of subtle changes associated with mortality in this sparse, uniformly vegetated ecosystem. We used the standardized precipitation index to characterize drought conditions and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery (250-m resolution) to characterize broad characteristics of growing season productivity. We calculated per-pixel growing season anomalies over a 16-year period (2000-2015) to identify the spatial and temporal variability in productivity. Metrics derived from Landsat satellite imagery (30-m resolution) were used to further investigate trends within anomalous areas at local scales. We found evidence to support an initial hypothesis that antecedent winter drought was most important in explaining reduced productivity. The results indicate drought effects were inconsistent over space and time. MODIS derived productivity deviated by more than four standard deviations in heavily impacted areas, but was well within the interannual variability in other areas. Growing season anomalies highlighted dramatic declines in productivity during the 2012 and 2013 growing seasons. However, large negative anomalies persisted in other areas during the 2014 growing season, indicating lag effects of drought. We are further investigating if the reduction in productivity is mediated by local biophysical properties. Our analysis identified spatially explicit patterns of ecosystem properties altered by severe drought which are consistent with

  17. Evaluating a seed technology for sagebrush restoration across an elevation gradient: support for bet hedging

    Science.gov (United States)

    Big sagebrush (Artemisia tridentata Nutt.) restoration is needed across vast areas, especially after large wildfires, to restore important ecosystem services. Sagebrush restoration success is inconsistent with a high rate of seeding failures, particularly at lower elevations. Seed enhancement tech...

  18. 76 FR 62087 - Draft Conservation Plan and Draft Environmental Assessment; Dunes Sagebrush Lizard, Texas

    Science.gov (United States)

    2011-10-06

    ...] Draft Conservation Plan and Draft Environmental Assessment; Dunes Sagebrush Lizard, Texas AGENCY: Fish... draft Texas Conservation Plan for the Dunes Sagebrush Lizard (TCP). The draft TCP will function as a... the Applicant for the dunes sagebrush lizard (Sceloporus arenicolus) throughout its range in Texas...

  19. Influence of container size on Wyoming big sagebrush seedling morphology and cold hardiness

    Science.gov (United States)

    Kayla R. Herriman; Anthony S. Davis; R. Kasten Dumroese

    2009-01-01

    Wyoming big sagebrush (Artemisia tridentata) is a key component of sagebrush steppe ecosystems and is a dominant shrub throughout the western United States. Our objective was to identify the effect of container size on plant morphology of Wyoming big sagebrush. We used three different stocktypes (45/340 ml [20 in3], 60/250 ml [15 in3], 112/105 ml [6....

  20. 76 FR 19304 - Endangered and Threatened Wildlife and Plants; Endangered Status for Dunes Sagebrush Lizard

    Science.gov (United States)

    2011-04-07

    ... for Dunes Sagebrush Lizard AGENCY: Fish and Wildlife Service, Interior. ACTION: Proposed rule... list the dunes sagebrush lizard (Sceloporus arenicolus) under the Endangered Species Act of 1973, as... dunes sagebrush lizard (Sceloporus arenicolus) that was published in the Federal Register on December 14...

  1. Legacy effects of no-analogue disturbances alter plant community diversity and composition in semi-arid sagebrush steppe

    Science.gov (United States)

    Ripplinger, Julie; Franklin, Janet; Edwards, Thomas C.

    2015-01-01

    Questions(i) What role does the type of managed disturbance play in structuring sagebrush steppe plant communities? (ii) How does the composition of post-disturbance plant communities change with time since disturbance? (iii) Does plant community diversity change over time following managed disturbance?LocationField study within the sagebrush steppe ecosystem. Rich County, Utah, USA.MethodsWe developed a chronosequence spanning up to 50 yrs post-treatment to study sagebrush steppe vegetation dynamics. Direct ordination was used to examine plant community composition by managed disturbance type and time since disturbance, and factorial analysis of covariance was used to examine diversity dynamics following disturbance. Indicator species values were calculated in order to identify characteristic species for each disturbance type.ResultsPlant communities experienced a shift toward distinct community composition for each of the three managed disturbance types, and gave no indication of returning to untreated community composition or diversity. Small post-disturbance increases in the number of non-native grass species were observed in the treatments relative to reference, with native forb species making the largest contribution to altered composition. On fire- and chemically-treated sites the proportional native forb species richness increased over time since disturbance, while the proportional contribution of non-native forbs to total species richness decreased. For all three treatment types, native grasses contributed less on average to total richness than on reference sites, while non-native grasses made up a higher proportion of total richness.ConclusionsCommon shrubland management techniques have legacy effects on the composition and diversity of sagebrush steppe plant communities, and no-analogue disturbances, such as chemical or mechanical treatments, have more pronounced legacy effects than treatments similar to natural disturbance regimes (fire). This study

  2. The economics of fuel management: Wildfire, invasive plants, and the dynamics of sagebrush rangelands in the western United States

    Science.gov (United States)

    Michael H. Taylor; Kimberly Rollins; Mimako Kobayashi; Robin J. Tausch

    2013-01-01

    In this article we develop a simulation model to evaluate the economic efficiency of fuel treatments and apply it to two sagebrush ecosystems in the Great Basin of the western United States: the Wyoming Sagebrush Steppe and Mountain Big Sagebrush ecosystems. These ecosystems face the two most prominent concerns in sagebrush ecosystems relative to wildfire: annual grass...

  3. Conservation of Sand Dune Vegetation in Coastal areas of the Valencian Region (Spain); Estado de conservacion de la vegetacion dunar en las costas de la comunidad Valenciana

    Energy Technology Data Exchange (ETDEWEB)

    Albertos, B.; San Miguel, E.; Draper, I.; Garilleti, R.; Lara, F.; Varela, J. M.

    2010-07-01

    The state of conservation of the coastal dune vegetation in Valencia region has been assessed within a survey of the vegetal communities present in these systems.The conservation status has been evaluated through a qualitative scale which integrates criteria such as dune extension, structure and diversity of the vegetal communities, level of ruderalization, presence of invasive species, and floristic rarity. Special attention has been paid to the usual aggressions to this type of ecosystem and the situation of the most aggressive invasive plants. (Author) 15 refs.

  4. Effects of prolonged drought on the vegetation cover of sand dunes in the NW Negev Desert: Field survey, remote sensing and conceptual modeling

    Science.gov (United States)

    Siegal, Z.; Tsoar, H.; Karnieli, A.

    2013-06-01

    Luminescence dating of stable sand dunes in the large deserts of the world has shown several episodes of mobility during the last 30 k years. The logical explanation for the mobility of fixed dunes is severe drought. Though drought length can be estimated, the level of precipitation drop is unknown. The stabilized sand dunes of the northwestern Negev Desert, Israel have been under an unprecedented prolonged drought since 1995. This has resulted in a vast decrease of shrubs cover on the fixed sand dunes, which changes along the rainfall gradient. In the north, an average of 27% of the shrubs had wilted by 2009, and in the drier southern area, 68% of the shrubs had withered. This loss of shrubbery is not expected to induce dune remobilization because the existing bio-crust cover is not negatively affected by the drought. Eleven aerial photographs taken over the drier southern area from 1956 to 2005 show the change in shrub cover due to human impact and the recent severe drought.

  5. Prescribed Fire Effects on Runoff, Erosion, and Soil Water Repellency on Steeply-Sloped Sagebrush Rangeland over a Five Year Period

    Science.gov (United States)

    Williams, C. J.; Pierson, F. B.; Al-Hamdan, O. Z.

    2014-12-01

    Fire is an inherent component of sagebrush steppe rangelands in western North America and can dramatically affect runoff and erosion processes. Post-fire flooding and erosion events pose substantial threats to proximal resources, property, and human life. Yet, prescribed fire can serve as a tool to manage vegetation and fuels on sagebrush rangelands and to reduce the potential for large catastrophic fires and mass erosion events. The impact of burning on event hydrologic and erosion responses is strongly related to the degree to which burning alters vegetation, ground cover, and surface soils and the intensity and duration of precipitation. Fire impacts on hydrologic and erosion response may be intensified or reduced by inherent site characteristics such as topography and soil properties. Parameterization of these diverse conditions in predictive tools is often limited by a lack of data and/or understanding for the domain of interest. Furthermore, hydrologic and erosion functioning change as vegetation and ground cover recover in the years following burning and few studies track these changes over time. In this study, we evaluated the impacts of prescribed fire on vegetation, ground cover, soil water repellency, and hydrologic and erosion responses 1, 2, and 5 yr following burning of a mountain big sagebrush community on steep hillslopes with fine-textured soils. The study site is within the Reynolds Creek Experimental Watershed, southwestern Idaho, USA. Vegetation, ground cover, and soil properties were measured over plot scales of 0.5 m2 to 9 m2. Rainfall simulations (0.5 m2) were used to assess the impacts of fire on soil water repellency, infiltration, runoff generation, and splash-sheet erosion. Overland flow experiments (9 m2) were used to assess the effects of fire-reduced ground cover on concentrated-flow runoff and erosion processes. The study results provide insight regarding fire impacts on runoff, erosion, and soil water repellency in the immediate and

  6. Models for predicting fuel consumption in sagebrush-dominated ecosystems

    Science.gov (United States)

    Clinton S. Wright

    2013-01-01

    Fuel consumption predictions are necessary to accurately estimate or model fire effects, including pollutant emissions during wildland fires. Fuel and environmental measurements on a series of operational prescribed fires were used to develop empirical models for predicting fuel consumption in big sagebrush (Artemisia tridentate Nutt.) ecosystems....

  7. Container configuration influences western larch and big sagebrush seedling development

    Science.gov (United States)

    Matthew Mehdi. Aghai

    2012-01-01

    Big sagebrush (Artemisia tridentata Nutt.), a woody shrub, and western larch (Larix occidentalis Nutt.), a deciduous conifer, are among many western North American species that have suffered a decline in presence and natural regeneration across their native ranges. These species are economically, ecologically, and intrinsically valuable, therefore many current...

  8. Scales of snow depth variability in high elevation rangeland sagebrush

    Science.gov (United States)

    Tedesche, Molly E.; Fassnacht, Steven R.; Meiman, Paul J.

    2017-09-01

    In high elevation semi-arid rangelands, sagebrush and other shrubs can affect transport and deposition of wind-blown snow, enabling the formation of snowdrifts. Datasets from three field experiments were used to investigate the scales of spatial variability of snow depth around big mountain sagebrush ( Artemisia tridentata Nutt.) at a high elevation plateau rangeland in North Park, Colorado, during the winters of 2002, 2003, and 2008. Data were collected at multiple resolutions (0.05 to 25 m) and extents (2 to 1000 m). Finer scale data were collected specifically for this study to examine the correlation between snow depth, sagebrush microtopography, the ground surface, and the snow surface, as well as the temporal consistency of snow depth patterns. Variograms were used to identify the spatial structure and the Moran's I statistic was used to determine the spatial correlation. Results show some temporal consistency in snow depth at several scales. Plot scale snow depth variability is partly a function of the nature of individual shrubs, as there is some correlation between the spatial structure of snow depth and sagebrush, as well as between the ground and snow depth. The optimal sampling resolution appears to be 25-cm, but over a large area, this would require a multitude of samples, and thus a random stratified approach is recommended with a fine measurement resolution of 5-cm.

  9. Woody fuels reduction in Wyoming big sagebrush communities

    Science.gov (United States)

    Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle & Young) ecosystems historically have been subject to disturbances that reduce or remove shrubs primarily by fire, although insect outbreaks and disease have also been important. Depending on site productivity, fire return in...

  10. Photochemical model evaluation of the ground-level ozone impacts on ambient air quality and vegetation health in the Alberta oil sands region: Using present and future emission scenarios

    Science.gov (United States)

    Vijayaraghavan, Krish; Cho, Sunny; Morris, Ralph; Spink, David; Jung, Jaegun; Pauls, Ron; Duffett, Katherine

    2016-09-01

    One of the potential environmental issues associated with oil sands development is increased ozone formation resulting from NOX and volatile organic compound emissions from bitumen extraction, processing and upgrading. To manage this issue in the Athabasca Oil Sands Region (AOSR) in northeast Alberta, a regional multi-stakeholder group, the Cumulative Environmental Management Association (CEMA), developed an Ozone Management Framework that includes a modelling based assessment component. In this paper, we describe how the Community Multi-scale Air Quality (CMAQ) model was applied to assess potential ground-level ozone formation and impacts on ambient air quality and vegetation health for three different ozone precursor cases in the AOSR. Statistical analysis methods were applied, and the CMAQ performance results met the U.S. EPA model performance goal at all sites. The modelled 4th highest daily maximum 8-h average ozone concentrations in the base and two future year scenarios did not exceed the Canada-wide standard of 65 ppb or the newer Canadian Ambient Air Quality Standards of 63 ppb in 2015 and 62 ppb in 2020. Modelled maximum 1-h ozone concentrations in the study were well below the Alberta Ambient Air Quality Objective of 82 ppb in all three cases. Several ozone vegetation exposure metrics were also evaluated to investigate the potential impact of ground-level ozone on vegetation. The chronic 3-months SUM60 exposure metric is within the CEMA baseline range (0-2000 ppb-hr) everywhere in the AOSR. The AOT40 ozone exposure metric predicted by CMAQ did not exceed the United Nations Economic Commission for Europe (UN/ECE) threshold of concern of 3000 ppb-hr in any of the cases but is just below the threshold in high-end future emissions scenario. In all three emission scenarios, the CMAQ predicted W126 ozone exposure metric is within the CEMA baseline threshold of 4000 ppb-hr. This study outlines the use of photochemical modelling of the impact of an industry (oil

  11. Conserving and restoring habitat for Greater Sage-Grouse and other sagebrush-obligate wildlife: The crucial link of forbs and sagebrush diversity

    Science.gov (United States)

    Kas Dumroese; Tara Luna; Bryce A. Richardson; Francis F. Kilkenny; Justin B. Runyon

    2015-01-01

    In the western US, Greater Sage-Grouse (Centrocercus urophasianus Bonaparte [Phasianidae]) have become an indicator species of the overall health of the sagebrush (Artemisia L. [Asteraceae]) dominated communities that support a rich diversity of flora and fauna. This species has an integral association with sagebrush, its understory forbs and grasses, and the...

  12. Range-wide assessment of livestock grazing across the sagebrush biome

    Science.gov (United States)

    Veblen, Kari E.; Pyke, David A.; Jones, Christopher A.; Casazza, Michael L.; Assal, Timothy J.; Farinha, Melissa A.

    2011-01-01

    synthesize recommendations from federal and university rangeland science experts about how BLM might prioritize collection of different types of livestock grazing-related natural resource data. 4. Investigate whether range-wide datasets (Objective 1) could be used in conjunction with remotely sensed imagery to identify across broad scales (a) allotments potentially not meeting BLM Land Health Standards (LHS) and (b) allotments in which unmet standards might be attributable to livestock grazing. Objective 1: We identified four datasets that potentially could be used for analyses of livestock grazing effects on sagebrush ecosystems. First, we obtained the most current spatial data (typically up to 2007, 2008, or 2009) for all BLM allotments and compiled data into a coarse, topologically enforced dataset that delineated grazing allotment boundaries. Second, we obtained LHS evaluation data (as of 2007) for all allotments across all districts and regions; these data included date of most recent evaluation, BLM determinations of whether region-specific standards were met, and whether BLM deemed livestock to have contributed to any unmet standards. Third, we examined grazing records of three types: Actual Use (permittee-reported), Billed Use (BLM-reported), and Permitted Use (legally authorized). Finally, we explored the possibility of using existing Natural Resources Conservation Service (NRCS) Ecological Site Description (ESD) data to make up-to-date estimates of production and forage availability on BLM allotments. Objective 2: We investigated the availability of BLM livestock grazing-related monitoring data and the status of LHS across 310 randomly selected allotments in 13 BLM field offices. We found that, relative to other data types, the most commonly available monitoring data were Actual Use numbers (permittee-reported livestock numbers and season-of-use), followed by Photo Point, forage Utilization, and finally, Vegetation Trend measurement data. Data availability and

  13. Is fire exclusion in mountain big sagebrush communities prudent? Soil nutrient, plant diversity, and arthropod response to burning

    Science.gov (United States)

    Fire has largely been excluded from many mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana (Rydb.) Beetle) communities. Land and wildlife managers are especially reluctant to reintroduce fire in mountain big sagebrush plant communities, especially those communities without significan...

  14. Sand consolidation

    Energy Technology Data Exchange (ETDEWEB)

    Spain, H H

    1965-01-21

    In a sand consolidation method in which there is injected a mixture of resin-forming liquids comprising an aryl-hydroxy low molecular weight compound, a water- soluble aldehyde, and a catalyst, an improvement is claimed which comprises diluting the resin-forming liquids with a diluent and with water so that the yield of the resin is sufficient to consolidate the sand particles with the minimum desirable pressure. The diluent may be mutually soluble in water and in the resin-forming liquids, and does not affect the setting time of the polymer. The aldehyde and the aryl-hydroxy compound may be in ratio of 5:1, and the diluent, methyl alcohol, is present in a ratio of 2:1 with reference to the water.

  15. Bumble bee (Hymenoptera: Apidae) community structure on two sagebrush steppe sites in southern Idaho

    Science.gov (United States)

    Stephen P. Cook; Sara M. Birch; Frank W. Merickel; Carrie Caselton Lowe; Deborah Page-Dumroese

    2011-01-01

    Although sagebrush, Artemisia spp., does not require an insect pollinator, there are several native species of bumble bees, Bombus spp. (Hymenoptera: Apidae), that are present in sagebrush steppe ecosystems where they act as pollinators for various forbs and shrubs. These native pollinators contribute to plant productivity and reproduction. We captured 12 species of...

  16. Restoration handbook for sagebrush steppe ecosystems with emphasis on greater sage-grouse habitat - Part 1

    Science.gov (United States)

    David A. Pyke; Jeanne C. Chambers; Mike Pellant; Steven T. Knick; Richard F. Miller; Jeffrey L. Beck; Paul S. Doescher; Eugene W. Schupp; Bruce A. Roundy; Mark Brunson; James D. McIver

    2015-01-01

    Sagebrush steppe ecosystems in the United States currently occur on only about one-half of their historical land area because of changes in land use, urban growth, and degradation of land, including invasions of non-native plants. The existence of many animal species depends on the existence of sagebrush steppe habitat. The greater sage-grouse (Centrocercus...

  17. Genetic and environmental effects on seed weight in subspecies of big sagebrush: Applications for restoration

    Science.gov (United States)

    Bryce A. Richardson; Hector G. Ortiz; Stephanie L. Carlson; Deidre M. Jaeger; Nancy L. Shaw

    2015-01-01

    The sagebrush steppe is a patchwork of species and subspecies occupying distinct environmental niches across the intermountain regions of western North America. These ecosystems face degradation from disturbances and exotic weeds. Using sagebrush seed that is matched to its appropriate niche is a critical component to successful restoration, improving habitat for the...

  18. Big sagebrush (Artemisia tridentata) in a shifting climate context: Assessment of seedling responses to climate

    Science.gov (United States)

    Martha A. Brabec

    2014-01-01

    The loss of big sagebrush (Artemisia tridentata) throughout the Great Basin Desert has motivated efforts to restore it because of fire and other disturbance effects on sagebrush-dependent wildlife and ecosystem function. Initial establishment is the first challenge to restoration, and appropriateness of seeds, climate, and weather variability are factors that may...

  19. Greater sage-grouse as an umbrella species for sagebrush-associated vertebrates.

    Science.gov (United States)

    Mary M. Rowland; Michael J. Wisdom; Lowell Suring; Cara W. Meinke

    2006-01-01

    Widespread degradation of the sagebrush ecosystem in the western United States, including the invasion of cheatgrass, has prompted resource managers to consider a variety of approaches to restore and conserve habitats for sagebrush-associated species. One such approach involves the use of greater sage-grouse, a species of prominent conservation interest, as an umbrella...

  20. Effects of using winter grazing as a fuel treatment on Wyoming big sagebrush plant communities

    Science.gov (United States)

    More frequent wildfires and incidences of mega-fires have increased the pressure for fuel treatments in sagebrush (Artemisia) communities. Winter grazing has been one of many fuel treatments proposed for Wyoming big sagebrush (A. tridentata Nutt. subsp. wyomingensis Beetle and A. Young) communitie...

  1. Wyoming big sagebrush: Efforts towards development of target plants for restoration

    Science.gov (United States)

    Kayla R. Herriman

    2009-01-01

    Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis) is a dominant shrub throughout much of the interior western United States. It is a key component of sagebrush steppe ecosystems, which have been degraded due to European settlement, improper land use, and changing fire regimes resulting from the invasion of exotic...

  2. Restoring big sagebrush after controlling encroaching western juniper with fire: aspect and subspecies effects

    Science.gov (United States)

    The need for restoration of shrubs is increasingly recognized around the world. In the western USA, restoration of mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana (Rydb.) Beetle) after controlling encroaching conifers is a priority to improve sagebrush-associated wildlife habitat. ...

  3. The response of big sagebrush (Artemisia tridentata) to interannual climate variation changes across its range.

    Science.gov (United States)

    Kleinhesselink, Andrew R; Adler, Peter B

    2018-05-01

    Understanding how annual climate variation affects population growth rates across a species' range may help us anticipate the effects of climate change on species distribution and abundance. We predict that populations in warmer or wetter parts of a species' range should respond negatively to periods of above average temperature or precipitation, respectively, whereas populations in colder or drier areas should respond positively to periods of above average temperature or precipitation. To test this, we estimated the population sensitivity of a common shrub species, big sagebrush (Artemisia tridentata), to annual climate variation across its range. Our analysis includes 8,175 observations of year-to-year change in sagebrush cover or production from 131 monitoring sites in western North America. We coupled these observations with seasonal weather data for each site and analyzed the effects of spring through fall temperatures and fall through spring accumulated precipitation on annual changes in sagebrush abundance. Sensitivity to annual temperature variation supported our hypothesis: years with above average temperatures were beneficial to sagebrush in colder locations and detrimental to sagebrush in hotter locations. In contrast, sensitivity to precipitation did not change significantly across the distribution of sagebrush. This pattern of responses suggests that regional abundance of this species may be more limited by temperature than by precipitation. We also found important differences in how the ecologically distinct subspecies of sagebrush responded to the effects of precipitation and temperature. Our model predicts that a short-term temperature increase could produce an increase in sagebrush cover at the cold edge of its range and a decrease in cover at the warm edge of its range. This prediction is qualitatively consistent with predictions from species distribution models for sagebrush based on spatial occurrence data, but it provides new mechanistic

  4. Insect community responses to climate and weather across elevation gradients in the Sagebrush Steppe, eastern Oregon

    Science.gov (United States)

    Pilliod, David S.; Rohde, Ashley T.

    2016-11-17

    Executive SummaryIn this study, the U.S. Geological Survey investigated the use of insects as bioindicators of climate change in sagebrush steppe shrublands and grasslands in the Upper Columbia Basin. The research was conducted in the Stinkingwater and Pueblo mountain ranges in eastern Oregon on lands administered by the Bureau of Land Management.We used a “space-for-time” sampling design that related insect communities to climate and weather along elevation gradients. We analyzed our insect dataset at three levels of organization: (1) whole-community, (2) feeding guilds (detritivores, herbivores, nectarivores, parasites, and predators), and (3) orders within nectarivores (i.e., pollinators). We captured 59,517 insects from 176 families and 10 orders at the Pueblo Mountains study area and 112,305 insects from 185 families and 11 orders at the Stinkingwater Mountains study area in 2012 and 2013. Of all the individuals captured at the Stinkingwater Mountains study area, 77,688 were from the family Cecidomyiidae (Diptera, gall gnats).We found that the composition of insect communities was associated with variability in long-term (30-yr) temperature and interannual fluctuations in temperature. We found that captures of certain fly, bee, moth, and butterfly pollinators were more strongly associated with some climate and vegetation variables than others. We found that timing of emergence, as measured by first detection of families, was associated with elevation. When analyzed by feeding guilds, we found that all guilds emerged later at high elevations except for detritivores, which emerged earlier at high elevations. The abundance of most taxa varied through time, mostly in response to temperature and precipitation. Of the pollinators, bees (particularly, Halictidae and Megachilidae) peaked in abundance in late June and early July, whereas butterflies and moths peaked in August. Flies peaked in abundance in July.Overall, our interpretation of these patterns is that

  5. Mineral sands

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    This paper presents an outlook of the Australian mineral sand industry and covers the major operators. It is shown that conscious of an environmentally minded public, the Australian miners have led the way in the rehabilitation of mined areas. Moreover the advanced ceramic industry is generating exciting new perspectives for zircon producers and there is a noticeable growth in the electronic market for rare earths, but in long term the success may depend as much on environmental management and communication skills as on mining and processing skills

  6. Simulated big sagebrush regeneration supports predicted changes at the trailing and leading edges of distribution shifts

    Science.gov (United States)

    Schlaepfer, Daniel R.; Taylor, Kyle A.; Pennington, Victoria E.; Nelson, Kellen N.; Martin, Trace E.; Rottler, Caitlin M.; Lauenroth, William K.; Bradford, John B.

    2015-01-01

    Many semi-arid plant communities in western North America are dominated by big sagebrush. These ecosystems are being reduced in extent and quality due to economic development, invasive species, and climate change. These pervasive modifications have generated concern about the long-term viability of sagebrush habitat and sagebrush-obligate wildlife species (notably greater sage-grouse), highlighting the need for better understanding of the future big sagebrush distribution, particularly at the species' range margins. These leading and trailing edges of potential climate-driven sagebrush distribution shifts are likely to be areas most sensitive to climate change. We used a process-based regeneration model for big sagebrush, which simulates potential germination and seedling survival in response to climatic and edaphic conditions and tested expectations about current and future regeneration responses at trailing and leading edges that were previously identified using traditional species distribution models. Our results confirmed expectations of increased probability of regeneration at the leading edge and decreased probability of regeneration at the trailing edge below current levels. Our simulations indicated that soil water dynamics at the leading edge became more similar to the typical seasonal ecohydrological conditions observed within the current range of big sagebrush ecosystems. At the trailing edge, an increased winter and spring dryness represented a departure from conditions typically supportive of big sagebrush. Our results highlighted that minimum and maximum daily temperatures as well as soil water recharge and summer dry periods are important constraints for big sagebrush regeneration. Overall, our results confirmed previous predictions, i.e., we see consistent changes in areas identified as trailing and leading edges; however, we also identified potential local refugia within the trailing edge, mostly at sites at higher elevation. Decreasing

  7. Invasive plants on disturbed Korean sand dunes

    Science.gov (United States)

    Kim, Kee Dae

    2005-01-01

    The sand dunes in coastal regions of South Korea are important ecosystems because of their small size, the rare species found in this habitat, and the beautiful landscapes they create. This study investigated the current vegetative status of sand dunes on three representative coasts of the Korean peninsula, and on the coasts of Cheju Island, and assessed the conditions caused by invasive plants. The relationships between the degree of invasion and 14 environmental variables were studied. Plots of sand dunes along line transects perpendicular to the coastal lines were established to estimate vegetative species coverage. TWINSPAN (Two-Way Indicator Species Analysis), CCA (Canonical Correspondence Analysis), and DCCA (Detrended Canonical Correspondence Analysis) were performed to classify communities on sand dunes and assess species composition variation. Carex kobomugi, Elymus mollis, and Vitex rotundifolia were found to be the dominant species plotted on the east, the west, and the peripheral coasts of Cheju Island, respectively. Vegetation on the south coast was totally extinct. The 19 communities, including representative C. kobomugi, C. kobomugi- Ixeris repens, C. kobomugi- Oenothera biennis, E. mollis, Lolium multiflorum- Calystegia soldanella, and V. rotundifolia- C. kobomugi, were all classified according to TWINSPAN. Oenothera biennis and L. multiflorum were exotics observed within these native communities. CCA showed that invasive native and exotic species distribution was segregated significantly, according to disturbance level, exotic species number, gravel, sand and silt contents, as well as vegetation size. It further revealed that human disturbance can strongly favor the settlement of invasive and exotic species. Restoration options to reduce exotic plants in the South Korean sand dune areas were found to be the introduction of native plant species from one sand dune into other sand dune areas, prohibition of building and the introduction of exotic

  8. U.S. Geological Survey sage-grouse and sagebrush ecosystem research annual report for 2017

    Science.gov (United States)

    Hanser, Steven E.

    2017-09-08

    The sagebrush (Artemisia spp.) ecosystem extends across a large portion of the Western United States, and the greater sage-grouse (Centrocercus urophasianus) is one of the iconic species of this ecosystem. Greater sage-grouse populations occur in 11 States and are dependent on relatively large expanses of sagebrush-dominated habitat. Sage-grouse populations have been experiencing long-term declines owing to multiple stressors, including interactions among fire, exotic plant invasions, and human land uses, which have resulted in significant loss, fragmentation, and degradation of landscapes once dominated by sagebrush. In addition to the sage-grouse, over 350 species of plants and animals are dependent on the sagebrush ecosystem.Increasing knowledge about how these species and the sagebrush ecosystem respond to these stressors and to management actions can inform and improve strategies to maintain existing areas of intact sagebrush and restore degraded landscapes. The U.S. Geological Survey (USGS) has a broad research program focused on providing the science needed to inform these strate-gies and to help land and resource managers at the Federal, State, Tribal, and local levels as they work towards sustainable sage-grouse populations and restored landscapes for the broad range of uses critical to stakeholders in the Western United States.USGS science has provided a foundation for major land and resource management decisions including those that precluded the need to list the greater sage-grouse under the Endangered Species Act. The USGS is continuing to build on that foundation to inform science-based decisions to help support local economies and the continued conservation, management, and restoration of the sagebrush ecosystem.This report contains descriptions of USGS sage-grouse and sagebrush ecosystem research projects that are ongoing or were active during 2017 and is organized into five thematic areas: Fire, Invasive Species, Restoration, Sagebrush and Sage

  9. Outplanting Wyoming big sagebrush following wldfire: stock performance and economics

    Science.gov (United States)

    Dettweiler-Robinson, Eva; Bakker, Jonathan D.; Evans, James R.; Newsome, Heidi; Davies, G. Matt; Wirth, Troy A.; Pyke, David A.; Easterly, Richard T.; Salstrom, Debra; Dunwiddle, Peter W.

    2013-01-01

    Finding ecologically and economically effective ways to establish matrix species is often critical for restoration success. Wyoming big sagebrush (Artemisia tridentata subsp. wyomingensis) historically dominated large areas of western North America, but has been extirpated from many areas by large wildfires; its re-establishment in these areas often requires active management. We evaluated the performance (survival, health) and economic costs of container and bare-root stock based on operational plantings of more than 1.5 million seedlings across 2 200 ha, and compared our plantings with 30 other plantings in which sagebrush survival was tracked for up to 5 yr. Plantings occurred between 2001 and 2007, and included 12 combinations of stock type, planting amendment, and planting year.We monitored 10 500 plants for up to 8 yr after planting. Survival to Year 3 averaged 21% and was higher for container stock (30%) than bare-root stock (17%). Survival did not differ among container stock plantings, whereas survival of bare-root stock was sometimes enhanced by a hydrogel dip before planting, but not by

  10. 2004 annual progress report: Stratton Sagebrush Hydrology Study Area: Establishment of a long-term research site in a high-elevation sagebrush steppe

    Science.gov (United States)

    Schoenecker, Kate; Lange, Bob; Calton, Mike

    2005-01-01

    In 2004 the U.S. Geological Survey, Fort Collins Science Center (FORT) and the Bureau of Land Management (BLM), Rawlins Field Office (RFO), began a cooperative effort to reestablish the Stratton Sagebrush Hydrology Study Area (Stratton) as a research location, with the goal of making it a site for long-term research on sagebrush (Artemisia spp.) ecology. No other long-term research sites in high-elevation sagebrush habitat currently exist, and the Stratton area, with its 30+ year history of research and baseline data, was a logical location to restart investigations aimed at answering pertinent and timely questions about sagebrush ecology and sagebrush-obligate species. During the first year of the study, USGS scientists conducted an in-depth literature search to locate publications from research conducted at Stratton. We contacted previous researchers to acquire literature and unpublished reports of work conducted at Stratton. Collated papers and published manuscripts were presented in an annotated bibliography (Burgess and Schoenecker, 2004).

  11. Direct and indirect effects of petroleum production activities on the western fence lizard (Sceloporus occidentalis) as a surrogate for the dunes sagebrush lizard (Sceloporus arenicolus).

    Science.gov (United States)

    Weir, Scott M; Knox, Ami; Talent, Larry G; Anderson, Todd A; Salice, Christopher J

    2016-05-01

    The dunes sagebrush lizard (Sceloporus arenicolus) is a habitat specialist of conservation concern limited to shin oak sand dune systems of New Mexico and Texas (USA). Because much of the dunes sagebrush lizard's habitat occurs in areas of high oil and gas production, there may be direct and indirect effects of these activities. The congeneric Western fence lizard (Sceloporus occidentalis) was used as a surrogate species to determine direct effects of 2 contaminants associated with oil and gas drilling activities in the Permian Basin (NM and TX, USA): herbicide formulations (Krovar and Quest) and hydrogen sulfide gas (H2S). Lizards were exposed to 2 concentrations of H2 S (30 ppm or 90 ppm) and herbicide formulations (1× or 2× label application rate) representing high-end exposure scenarios. Sublethal behavioral endpoints were evaluated, including sprint speed and time to prey detection and capture. Neither H2S nor herbicide formulations caused significant behavioral effects compared to controls. To understand potential indirect effects of oil and gas drilling on the prey base, terrestrial invertebrate biomass and order diversity were quantified at impacted sites to compare with nonimpacted sites. A significant decrease in biomass was found at impacted sites, but no significant effects on diversity. The results suggest little risk from direct toxic effects, but the potential for indirect effects should be further explored. © 2015 SETAC.

  12. Mechanical mastication of Utah juniper encroaching sagebrush steppe increases inorganic soil N

    Science.gov (United States)

    Juniper (Juniperus spp.) has encroached millions of hectares of sagebrush (Artemisia spp.) steppe. Juniper mechanical mastication increases cover of understory species, but could increase resource availability and subsequently invasive plant species. We quantified the effects of juniper mastication ...

  13. Mountain big sagebrush age distribution and relationships on the northern Yellowstone Winter Range

    Science.gov (United States)

    Carl L. Wambolt; Trista L. Hoffman

    2001-01-01

    This study was conducted within the Gardiner Basin, an especially critical wintering area for native ungulates utilizing the Northern Yellowstone Winter Range. Mountain big sagebrush plants on 33 sites were classified as large (≥22 cm canopy cover), small (

  14. Short-term regeneration dynamics of Wyoming big sagebrush at two sites in northern Utah

    Science.gov (United States)

    The herbicide tebuthiuron has been used historically to control cover of Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis - complete taxonomic designation), a widespread shrub across the western United States, with the intent of increasing herbaceous plant cover. Although the tebuthiur...

  15. Attempting to restore herbaceous understories in Wyoming big sagebrush communities with mowing and seeding

    Science.gov (United States)

    Shrub steppe communities with depleted perennial herbaceous understories need to be restored to increase resilience, provide quality wildlife habitat, and improve ecosystem function. Mowing has been applied to Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle &Young) steppe...

  16. Protocols for sagebrush seed processing and seedling production at the Lucky Peak Nursery

    Science.gov (United States)

    Clark D. Fleege

    2010-01-01

    This paper presents the production protocols currently practiced at the USDA Forest Service Lucky Peak Nursery (Boise, ID) for seed processing and bareroot and container seedling production for three subspecies of big sagebrush (Artemisia tridentata).

  17. Modeling regeneration responses of big sagebrush (Artemisia tridentata) to abiotic conditions

    Science.gov (United States)

    Schlaepfer, Daniel R.; Lauenroth, William K.; Bradford, John B.

    2014-01-01

    Ecosystems dominated by big sagebrush, Artemisia tridentata Nuttall (Asteraceae), which are the most widespread ecosystems in semiarid western North America, have been affected by land use practices and invasive species. Loss of big sagebrush and the decline of associated species, such as greater sage-grouse, are a concern to land managers and conservationists. However, big sagebrush regeneration remains difficult to achieve by restoration and reclamation efforts and there is no regeneration simulation model available. We present here the first process-based, daily time-step, simulation model to predict yearly big sagebrush regeneration including relevant germination and seedling responses to abiotic factors. We estimated values, uncertainty, and importance of 27 model parameters using a total of 1435 site-years of observation. Our model explained 74% of variability of number of years with successful regeneration at 46 sites. It also achieved 60% overall accuracy predicting yearly regeneration success/failure. Our results identify specific future research needed to improve our understanding of big sagebrush regeneration, including data at the subspecies level and improved parameter estimates for start of seed dispersal, modified wet thermal-time model of germination, and soil water potential influences. We found that relationships between big sagebrush regeneration and climate conditions were site specific, varying across the distribution of big sagebrush. This indicates that statistical models based on climate are unsuitable for understanding range-wide regeneration patterns or for assessing the potential consequences of changing climate on sagebrush regeneration and underscores the value of this process-based model. We used our model to predict potential regeneration across the range of sagebrush ecosystems in the western United States, which confirmed that seedling survival is a limiting factor, whereas germination is not. Our results also suggested that modeled

  18. Surface fluxes and water balance of spatially varying vegetation within a small mountainous headwater catchment

    Directory of Open Access Journals (Sweden)

    G. N. Flerchinger

    2010-06-01

    Full Text Available Precipitation variability and complex topography often create a mosaic of vegetation communities in mountainous headwater catchments, creating a challenge for measuring and interpreting energy and mass fluxes. Understanding the role of these communities in modulating energy, water and carbon fluxes is critical to quantifying the variability in energy, carbon, and water balances across landscapes. The focus of this paper was: (1 to demonstrate the utility of eddy covariance (EC systems in estimating the evapotranspiration component of the water balance of complex headwater mountain catchments; and (2 to compare and contrast the seasonal surface energy and carbon fluxes across a headwater catchment characterized by large variability in precipitation and vegetation cover. Eddy covariance systems were used to measure surface fluxes over sagebrush (Artemesia arbuscula and Artemesia tridentada vaseyana, aspen (Populus tremuloides and the understory of grasses and forbs beneath the aspen canopy. Peak leaf area index of the sagebrush, aspen, and aspen understory was 0.77, 1.35, and 1.20, respectively. The sagebrush and aspen canopies were subject to similar meteorological forces, while the understory of the aspen was sheltered from the wind. Missing periods of measured data were common and made it necessary to extrapolate measured fluxes to the missing periods using a combination of measured and simulated data. Estimated cumulative evapotranspiratation from the sagebrush, aspen trees, and aspen understory were 384 mm, 314 mm and 185 mm. A water balance of the catchment indicated that of the 699 mm of areal average precipitation, 421 mm was lost to evapotranspiration, and 254 mm of streamflow was measured from the catchment; water balance closure for the catchment was within 22 mm. Fluxes of latent heat and carbon for all sites were minimal through the winter. Growing season fluxes of latent heat and carbon were consistently higher

  19. Evaluation of an Intergrated / Biocoagulant-sand filter Drum for ...

    African Journals Online (AJOL)

    User

    2015-03-18

    Mar 18, 2015 ... to adopt simple sand filtration for water treatment is exigent. ... Moringa oleifera, a vegetable plant found across Africa have been noted ... leachate samples from waste dumps within the city of Bamenda .... Total solids mg/dm3.

  20. Provenance of Coastal dune sands along Red Sea, Egypt

    Indian Academy of Sciences (India)

    26

    accumulation of sands behind vegetation or any other obstacles. ... The study areas Safaga (SF) and Quseir (QS) field dunes (Fig. 1) ..... coastal dune sands were deposited in a passive margin of a synrift .... Sed Petrol 63(6), 1110-1117.

  1. Sand dune tracking from satellite laser altimetry

    Science.gov (United States)

    Dabboor, Mohammed

    Substantial problems arise from sand movement in arid and semi-arid countries. Sand poses a threat to infrastructure, agricultural and urban areas. These issues are caused by the encroachment of sand on roads and railway tracks, farmland, towns and villages, and airports, to name a few. Sand movement highly depends on geomorphology including vegetation cover, shape and height of the terrain, and grain size of the sand. However, wind direction and speed are the most important factors that affect efficient sand movement. The direction of the movement depends on the main direction of the wind, but it has been shown that a minimum wind speed is required, e.g. wind gusts, to initiate sand transport. This fact prevents a simple calculation of sand transport from conventional wind data as wind records rarely contain sub-minute intervals masking out any wind gusts. An alternative of predicting sand transport is the direct observation of sand advance by in situ measurements or via satellite. Until recently, satellite imagery was the only means to compare dune shape and position for predicting dune migration over several years. In 2003, the NASA laser altimetry mission ICESat became operational and monitors elevations over all surface types including sand dunes with an accuracy of about 10-20 cm. In this study, ICESat observations from repeat tracks (tracks overlapping eachother within 50 m) are used to derive sand dune advance and direction. The method employs a correlation of the elevation profiles over several dunes and was sucessfully validated with synthetic data. The accuracy of this method is 5 meters of dune advance. One of the most active areas exhibiting sand and dune movement is the area of the Arabian Peninsula. Approximately one-third of the Arabian Peninsula is covered by sand dunes. Different wind regimes (Shamal, Kaus) cause sand dune movement in the selected study area in the eastern part of the Arabian Peninsula between 20-25 degrees North and 45-55 degrees

  2. Land use and habitat conditions across the southwestern Wyoming sagebrush steppe: development impacts, management effectiveness and the distribution of invasive plants

    Science.gov (United States)

    Manier, Daniel J.; Aldridge, Cameron L.; Anderson, Patrick; Chong, Geneva; Homer, Collin G.; O'Donnell, Michael S.; Schell, Spencer

    2011-01-01

    sampling focused on the interaction between human infrastructure and weedy plant distributions in southwestern Wyoming, while also capturing spatial variability associated with growing conditions and management across the region. In a separate but linked study, we also sampled native and invasive composition of recent and historic habitat treatments. Here, we summarize findings of this ongoing work, highlighting patterns and relationships between vegetation (native and invasive), land cover, landform, and land-use patterns in the sagebrush steppe.

  3. Sagebrush, greater sage-grouse, and the occurrence and importance of forbs

    Science.gov (United States)

    Pennington, Victoria E.; Schlaepfer, Daniel R.; Beck, Jeffrey L.; Bradford, John B.; Palmquist, Kyle A.; Lauenroth, William K.

    2016-01-01

    Big sagebrush (Artemisia tridentata Nutt.) ecosystems provide habitat for sagebrush-obligate wildlife species such as the Greater Sage-Grouse (Centrocercus urophasianus). The understory of big sagebrush plant communities is composed of grasses and forbs that are important sources of cover and food for wildlife. The grass component is well described in the literature, but the composition, abundance, and habitat role of forbs in these communities is largely unknown. Our objective was to synthesize information about forbs and their importance to Greater Sage-Grouse diets and habitats, how rangeland management practices affect forbs, and how forbs respond to changes in temperature and precipitation. We also sought to identify research gaps and needs concerning forbs in big sagebrush plant communities. We searched for relevant literature including journal articles and state and federal agency reports. Our results indicated that in the spring and summer, Greater Sage-Grouse diets consist of forbs (particularly species in the Asteraceae family), arthropods, and lesser amounts of sagebrush. The diets transition to sagebrush in fall and winter. Forbs provide cover for Greater Sage-Grouse individuals at their lekking, nesting, and brood-rearing sites, and the species has a positive relationship with arthropod presence. The effect of grazing on native forbs may be compounded by invasion of nonnative species and differs depending on grazing intensity. The effect of fire on forbs varies greatly and may depend on time elapsed since burning. In addition, chemical and mechanical treatments affect annual and perennial forbs differently. Temperature and precipitation influence forb phenology, biomass, and abundance differently among species. Our review identified several uncertainties and research needs about forbs in big sagebrush ecosystems. First, in many cases the literature about forbs is reported only at the genus or functional type level. Second, information about forb

  4. Restoration handbook for sagebrush steppe ecosystems with emphasis on greater sage-grouse habitat - Part 3: Site level restoration decisions

    Science.gov (United States)

    David A. Pyke; Jeanne C. Chambers; Mike Pellant; Richard F. Miller; Jeffrey L. Beck; Paul S. Doescher; Bruce A. Roundy; Eugene W. Schupp; Steven T. Knick; Mark Brunson; James D. McIver

    2017-01-01

    Sagebrush steppe ecosystems in the United States currently (2016) occur on only about one-half of their historical land area because of changes in land use, urban growth, and degradation of land, including invasions of non-native plants. The existence of many animal species depends on the existence of sagebrush steppe habitat. The greater sage-grouse (Centrocercus...

  5. The Sagebrush Steppe Treatment Evaluation Project (SageSTEP): a test of state-and-transition theory

    Science.gov (United States)

    James D. McIver; Mark Brunson; Steve C. Bunting; Jeanne Chambers; Nora Devoe; Paul Doescher; James Grace; Dale Johnson; Steve Knick; Richard Miller; Mike Pellant; Fred Pierson; David Pyke; Kim Rollins; Bruce Roundy; Eugene Schupp; Robin Tausch; David Turner

    2010-01-01

    The Sagebrush Steppe Treatment Evaluation Project (SageSTEP) is a comprehensive, integrated, long-term study that evaluates the ecological effects of fire and fire surrogate treatments designed to reduce fuel and to restore sagebrush (Artemisia spp.) communities of the Great Basin and surrounding areas. SageSTEP has several features that make it ideal for testing...

  6. The role of symbiotic nitrogen fixation in nitrogen availability, competition and plant invasion into the sagebrush steppe

    Science.gov (United States)

    Erin M. Goergen

    2009-01-01

    In the semi-arid sagebrush steppe of the Northeastern Sierra Nevada, resources are both spatially and temporally variable, arguably making resource availability a primary factor determining invasion success. N fixing plant species, primarily native legumes, are often relatively abundant in sagebrush steppe and can contribute to ecosystem nitrogen budgets. ...

  7. Characterization of a sagebrush (Artemisia tridentata ssp. wyomingensis) die-off on the Handford Site

    International Nuclear Information System (INIS)

    Cardenas, A.; Lewinsohn, J.; Auger, C.; Downs, J.L.; Cadwell, L.L.; Burrows, R.

    1997-09-01

    The Hanford Site contains one of the few remaining contiguous areas of shrub-steppe habitat left in Washington State. This habitat is home to many native plant and wildlife species, some of which are threatened with extinction or are unique to the Site. The importance of the Hanford Site increases as other lands surrounding the Site are developed, and these native species and habitats are lost. Stands of Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) on the Site are a particularly important component of shrub-steppe habitat, because a number of wildlife require big sagebrush for food and cover. Since 1993, researchers and field biologists have made anecdotal observations of dying and declining sagebrush in stands of shrubs near the 100 Areas. This study was initiated to delineate and document the general boundary where sagebrush stands appear to be declining. We mapped the areal extent of the die-off using a global positioning system and found that the central portion of the die-off encompasses 280 hectares. Shrub stand defoliation was estimated to be near or greater than 80% in this area. The remainder of the die-off area exhibits varying mixtures of completely defoliated, partially defoliated, and healthy-looking stands. Declining sagebrush stands comprise a total of 1776 hectares

  8. Characterization of a sagebrush (Artemisia tridentata ssp. wyomingensis) die-off on the Handford Site

    Energy Technology Data Exchange (ETDEWEB)

    Cardenas, A.; Lewinsohn, J.; Auger, C.; Downs, J.L.; Cadwell, L.L.; Burrows, R.

    1997-09-01

    The Hanford Site contains one of the few remaining contiguous areas of shrub-steppe habitat left in Washington State. This habitat is home to many native plant and wildlife species, some of which are threatened with extinction or are unique to the Site. The importance of the Hanford Site increases as other lands surrounding the Site are developed, and these native species and habitats are lost. Stands of Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) on the Site are a particularly important component of shrub-steppe habitat, because a number of wildlife require big sagebrush for food and cover. Since 1993, researchers and field biologists have made anecdotal observations of dying and declining sagebrush in stands of shrubs near the 100 Areas. This study was initiated to delineate and document the general boundary where sagebrush stands appear to be declining. We mapped the areal extent of the die-off using a global positioning system and found that the central portion of the die-off encompasses 280 hectares. Shrub stand defoliation was estimated to be near or greater than 80% in this area. The remainder of the die-off area exhibits varying mixtures of completely defoliated, partially defoliated, and healthy-looking stands. Declining sagebrush stands comprise a total of 1776 hectares.

  9. Nest mortality of sagebrush songbirds due to a severe hailstorm

    Science.gov (United States)

    Hightower, Jessica N.; Carlisle, Jason D.; Chalfoun, Anna D.

    2018-01-01

    Demographic assessments of nesting birds typically focus on failures due to nest predation or brood parasitism. Extreme weather events such as hailstorms, however, can also destroy eggs and injure or kill juvenile and adult birds at the nest. We documented the effects of a severe hailstorm on 3 species of sagebrush-associated songbirds: Sage Thrasher (Oreoscoptes montanus), Brewer's Sparrow (Spizella breweri), and Vesper Sparrow (Pooecetes gramineus), nesting at eight 24 ha study plots in central Wyoming, USA. Across all plots, 17% of 128 nests failed due to the hailstorm; however, all failed nests were located at a subset of study plots (n = 3) where the hailstorm was most intense, and 45% of all nests failures on those plots were due to hail. Mortality rates varied by species, nest architecture, and nest placement. Nests with more robust architecture and those sited more deeply under the shrub canopy were more likely to survive the hailstorm, suggesting that natural history traits may modulate mortality risk due to hailstorms. While sporadic in nature, hailstorms may represent a significant source of nest failure to songbirds in certain locations, especially with increasing storm frequency and severity forecasted in some regions with ongoing climate change.

  10. Eastern Scheldt Sand, Baskarp Sand No. 15

    DEFF Research Database (Denmark)

    Andersen, A. T; Madsen, E. B.; Schaarup-Jensen, A. L.

    The present data report contains data from 13 drained triaxial tests, performed on two different sand types in the Soil Mechanics Laboratory at Aalborg University in March, 1997. Two tests have been performed on Baskarp Sand No. 15, which has already ken extensively tested in the Soil Mechanics...... Laboratory. The remaining 11 triaxial tests have ben performed on Eastern Scheldt Sand, which is a material not yet investigated at the Soil Mechanics Laboratory. In the first pari of this data report, the characteristics of the two sand types in question will be presented. Next, a description...... will described. In this connection, the procedure for preparation of the soil specimens will be presented, and the actual performance of the tests will be briefly outlined. Finally, the procedure for processing of the measurements from the laboratory in order to obtain usable data will be described. The final...

  11. Fungal and bacterial contributions to nitrogen cycling in cheatgrass-invaded and uninvaded native sagebrush soils of the western USA

    Science.gov (United States)

    DeCrappeo, Nicole; DeLorenze, Elizabeth J.; Giguere, Andrew T; Pyke, David A.; Bottomley, Peter J.

    2017-01-01

    AimThere is interest in determining how cheatgrass (Bromus tectorum L.) modifies N cycling in sagebrush (Artemisia tridentata Nutt.) soils of the western USA.MethodsTo gain insight into the roles of fungi and bacteria in N cycling of cheatgrass-invaded and uninvaded sagebrush soils, the fungal protein synthesis inhibitor, cycloheximide (CHX), and the bacteriocidal compound, bronopol (BRO) were combined with a 15NH4+ isotope pool dilution approach.ResultsCHX reduced gross N mineralization to the same rate in both sagebrush and cheatgrass soils indicating a role for fungi in N mineralization in both soil types. In cheatgrass soils BRO completely inhibited gross N mineralization, whereas, in sagebrush soils a BRO-resistant gross N mineralization rate was detected that was slower than CHX sensitive gross N mineralization, suggesting that the microbial drivers of gross N mineralization were different in sagebrush and cheatgrass soils. Net N mineralization was stimulated to a higher rate in sagebrush than in cheatgrass soils by CHX, implying that a CHX inhibited N sink was larger in the former than the latter soils. Initial gross NH4+ consumption rates were reduced significantly by both CHX and BRO in both soil types, yet, consumption rates recovered significantly between 24 and 48 h in CHX-treated sagebrush soils. The recovery of NH4+ consumption in sagebrush soils corresponded with an increase in the rate of net nitrification.ConclusionsThese results suggest that cheatgrass invasion of sagebrush soils of the northern Great Basin reduces the capacity of the fungal N consumption sink, enhances the capacity of a CHX resistant N sink and alters the contributions of bacteria and fungi to gross N mineralization.

  12. Calibration of remotely sensed, coarse resolution NDVI to CO2 fluxes in a sagebrush-steppe ecosystem

    Science.gov (United States)

    Wylie, B.K.; Johnson, D.A.; Laca, Emilio; Saliendra, Nicanor Z.; Gilmanov, T.G.; Reed, B.C.; Tieszen, L.L.; Worstell, B.B.

    2003-01-01

    The net ecosystem exchange (NEE) of carbon flux can be partitioned into gross primary productivity (GPP) and respiration (R). The contribution of remote sensing and modeling holds the potential to predict these components and map them spatially and temporally. This has obvious utility to quantify carbon sink and source relationships and to identify improved land management strategies for optimizing carbon sequestration. The objective of our study was to evaluate prediction of 14-day average daytime CO2 fluxes (Fday) and nighttime CO2 fluxes (Rn) using remote sensing and other data. Fday and Rn were measured with a Bowen ratio-energy balance (BREB) technique in a sagebrush (Artemisia spp.)-steppe ecosystem in northeast Idaho, USA, during 1996-1999. Micrometeorological variables aggregated across 14-day periods and time-integrated Advanced Very High Resolution Radiometer (AVHRR) Normalized Difference Vegetation Index (iNDVI) were determined during four growing seasons (1996-1999) and used to predict Fday and Rn. We found that iNDVI was a strong predictor of Fday (R2 = 0.79, n = 66, P improved predictions of Fday (R2= 0.82, n = 66, P management strategies, carbon certification, and validation and calibration of carbon flux models. ?? 2003 Elsevier Science Inc. All rights reserved.

  13. 75 FR 77801 - Endangered and Threatened Wildlife and Plants; Endangered Status for Dunes Sagebrush Lizard

    Science.gov (United States)

    2010-12-14

    ... public lands in Texas. It is evident that the dunes sagebrush lizard is still present at the park, but... expected to contribute to habitat loss, modification, or fragmentation in the future include wind and solar... and Solar Energy Development Eastern New Mexico and western Texas are highly suitable areas for wind...

  14. Tapping soil survey information for rapid assessment of sagebrush ecosystem resilience and resistance

    Science.gov (United States)

    Jeremy D. Maestas; Steven B. Campbell; Jeanne C. Chambers; Mike Pellant; Richard F. Miller

    2016-01-01

    A new ecologically-based approach to risk abatement has emerged that can aid land managers in grappling with escalating impacts of large-scale wildfire and invasive annual grasses in sagebrush ecosystems, particularly in the Great Basin. Specifically, ecosystem resilience and resistance (R&R) concepts have been more fully operationalized from regional...

  15. Selecting sagebrush seed sources for restoration in a variable climate: ecophysiological variation among genotypes

    Science.gov (United States)

    Germino, Matthew J.

    2012-01-01

    Big sagebrush (Artemisia tridentata) communities dominate a large fraction of the United States and provide critical habitat for a number of wildlife species of concern. Loss of big sagebrush due to fire followed by poor restoration success continues to reduce ecological potential of this ecosystem type, particularly in the Great Basin. Choice of appropriate seed sources for restoration efforts is currently unguided due to knowledge gaps on genetic variation and local adaptation as they relate to a changing landscape. We are assessing ecophysiological responses of big sagebrush to climate variation, comparing plants that germinated from ~20 geographically distinct populations of each of the three subspecies of big sagebrush. Seedlings were previously planted into common gardens by US Forest Service collaborators Drs. B. Richardson and N. Shaw, (USFS Rocky Mountain Research Station, Provo, Utah and Boise, Idaho) as part of the Great Basin Native Plant Selection and Increase Project. Seed sources spanned all states in the conterminous Western United States. Germination, establishment, growth and ecophysiological responses are being linked to genomics and foliar palatability. New information is being produced to aid choice of appropriate seed sources by Bureau of Land Management and USFS field offices when they are planning seed acquisitions for emergency post-fire rehabilitation projects while considering climate variability and wildlife needs.

  16. Birds of a Great Basin Sagebrush Habitat in East-Central Nevada

    OpenAIRE

    United States Department of Agriculture, Forest Service

    1992-01-01

    Breeding bird populations ranged from 3.35 to 3.48 individuals/ha over a 3-year study conducted from 1981 to 1983. Brewer's sparrows, sage sparrows, sage thrashers, and black-throated sparrows were numerically dominant. Horned larks and western meadowlarks were less common. Results are compared with bird populations in Great Basin sagebrush habitats elsewhere in the United States.

  17. Attempting to restore mountain big sagebrush (Artemisia tridentata ssp. vaseyana) four years after fire

    Science.gov (United States)

    Restoration of shrubs is increasingly needed throughout the world because of altered fire regimes, anthropogenic disturbance, and over-utilization. The native shrub mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana (Rydb.) Beetle) is a restoration priority in western North America be...

  18. Do container volume, site preparation, and field fertilization affect restoration potential of Wyoming big sagebrush?

    Science.gov (United States)

    Kayla R. Herriman; Anthony S. Davis; Kent G. Apostol; Olga. A. Kildisheva; Amy L. Ross-Davis; Kas Dumroese

    2016-01-01

    Land management practices, invasive species expansion, and changes in the fire regime greatly impact the distribution of native plants in natural areas. Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis), a keystone species in the Great Basin, has seen a 50% reduction in its distribution. For many dryland species, reestablishment efforts have...

  19. Evaluating winter/spring seeding of a native perennial bunchgrass in the sagebrush steppe

    Science.gov (United States)

    Sagebrush (Artemisia tridentata Nutt.) plant communities in the US Great Basin region are being severely impacted by increasingly frequent wildfires in association with the expansion of exotic annual grasses. Maintenance of native perennial bunchgrasses is key to controlling annual grass expansion,...

  20. Variation in sagebrush communities historically seeded with crested wheatgrass in the eastern great basin

    Science.gov (United States)

    Although crested wheatgrass (CWG; Agropyron cristatum [L.] Gaertn.) has been one of the most commonly seeded exotic species in the western United States, long-term successional trajectories of seeded sites are poorly characterized, especially for big sagebrush (Artemisia tridentana Nutt.) ecosystems...

  1. Influence green sand system by core sand additions

    Directory of Open Access Journals (Sweden)

    N. Špirutová

    2012-01-01

    Full Text Available Today, about two thirds of iron alloys casting (especially for graphitizing alloys of iron are produced into green sand systems with usually organically bonded cores. Separation of core sands from the green sand mixture is very difficult, after pouring. The core sand concentration increase due to circulation of green sand mixture in a closed circulation system. Furthermore in some foundries, core sands have been adding to green sand systems as a replacement for new sands. The goal of this contribution is: “How the green sand systems are influenced by core sands?”This effect is considered by determination of selected technological properties and degree of green sand system re-bonding. From the studies, which have been published yet, there is not consistent opinion on influence of core sand dilution on green sand system properties. In order to simulation of the effect of core sands on the technological properties of green sands, there were applied the most common used technologies of cores production, which are based on bonding with phenolic resin. Core sand concentration added to green sand system, was up to 50 %. Influence of core sand dilution on basic properties of green sand systems was determined by evaluation of basic industrial properties: moisture, green compression strength and splitting strength, wet tensile strength, mixture stability against staling and physical-chemistry properties (pH, conductivity, and loss of ignition. Ratio of active betonite by Methylene blue test was also determined.

  2. Challenges of establishing big sgebrush (Artemisia tridentata) in rangeland restoration: effects of herbicide, mowing, whole-community seeding, and sagebrush seed sources

    Science.gov (United States)

    Brabec, Martha M.; Germino, Matthew J.; Shinneman, Douglas J.; Pilliod, David S.; McIlroy, Susan K.; Arkle, Robert S.

    2015-01-01

    The loss of big sagebrush (Artemisia tridentata Nutt.) on sites disturbed by fire has motivated restoration seeding and planting efforts. However, the resulting sagebrush establishment is often lower than desired, especially in dry areas. Sagebrush establishment may be increased by addressing factors such as seed source and condition or management of the plant community. We assessed initial establishment of seeded sagebrush and four populations of small outplants (from different geographies, climates, and cytotypes) and small sagebrush outplants in an early seral community where mowing, herbicide, and seeding of other native plants had been experimentally applied. No emergence of seeded sagebrush was detected. Mowing the site before planting seedlings led to greater initial survival probabilities for sagebrush outplants, except where seeding also occurred, and these effects were related to corresponding changes in bare soil exposure. Initial survival probabilities were > 30% greater for the local population of big sagebrush relative to populations imported to the site from typical seed transfer distances of ~320–800 km. Overcoming the high first-year mortality of outplanted or seeded sagebrush is one of the most challenging aspects of postfire restoration and rehabilitation, and further evaluation of the impacts of herb treatments and sagebrush seed sources across different site types and years is needed.

  3. Singing Sand Dunes

    Indian Academy of Sciences (India)

    ble low-frequency (s. 75–105 Hz), that can some- times be heard up to 10 km away. Scientific in- vestigations suggest that the sustained low fre- quency sound of sand dunes that resembles a pure note from a musical instrument, is due to the synchronized motion of well-sorted dry sand grains when they spontaneously ...

  4. Ecosystem functional response across precipitation extremes in a sagebrush steppe.

    Science.gov (United States)

    Tredennick, Andrew T; Kleinhesselink, Andrew R; Taylor, J Bret; Adler, Peter B

    2018-01-01

    Precipitation is predicted to become more variable in the western United States, meaning years of above and below average precipitation will become more common. Periods of extreme precipitation are major drivers of interannual variability in ecosystem functioning in water limited communities, but how ecosystems respond to these extremes over the long-term may shift with precipitation means and variances. Long-term changes in ecosystem functional response could reflect compensatory changes in species composition or species reaching physiological thresholds at extreme precipitation levels. We conducted a five year precipitation manipulation experiment in a sagebrush steppe ecosystem in Idaho, United States. We used drought and irrigation treatments (approximately 50% decrease/increase) to investigate whether ecosystem functional response remains consistent under sustained high or low precipitation. We recorded data on aboveground net primary productivity (ANPP), species abundance, and soil moisture. We fit a generalized linear mixed effects model to determine if the relationship between ANPP and soil moisture differed among treatments. We used nonmetric multidimensional scaling to quantify community composition over the five years. Ecosystem functional response, defined as the relationship between soil moisture and ANPP, was similar among irrigation and control treatments, but the drought treatment had a greater slope than the control treatment. However, all estimates for the effect of soil moisture on ANPP overlapped zero, indicating the relationship is weak and uncertain regardless of treatment. There was also large spatial variation in ANPP within-years, which contributes to the uncertainty of the soil moisture effect. Plant community composition was remarkably stable over the course of the experiment and did not differ among treatments. Despite some evidence that ecosystem functional response became more sensitive under sustained drought conditions, the response

  5. New generation expandable sand screens

    OpenAIRE

    Syltøy, Christer

    2014-01-01

    Master's thesis in Petroleum engineering This thesis aims to give a general insight into sand control and various sorts of sand control measures and applications of sand control tools. Special focus will be given to expandable sand screens – a technology which came about in the late 1990’s through the use of flexible, expandable tubulars as base pipe in sand screens. More specifically Darcy’s Hydraulic Endurance Screens, a compliant sand screen system using hydraulic activation, and the fu...

  6. Holocene beach buildup and coastal aeolian sand incursions off the Nile littoral cell

    Science.gov (United States)

    Roskin, Joel; Sivan, Dorit; Shtienberg, Gilad; Porat, Naomi; Bookman, Revital

    2017-04-01

    Israel's coastal plain is abundant with sand originating from the Nile littoral cell. The inland windblown loose sand has formed 3-6 km wide lobe-like sand and dune fields currently comprised of foredunes, linear and northeasterly facing transverse and parabolic dunes that are currently stabilized by vegetation. This study reviews the architecture and history of the these dune fields aiming to: (a) Date the timings of beach accretion, and sand and dune incursions. (b) Discriminate between natural and human-induced forcing factors of sand mobilization and stabilization in time and space. (c) Present a model of the dunescape development. (d) Assess scenarios of sand transport in the future charcaterized by intense human impact and climate change. Luminescence ages, radiocarbon dates and relative ages from previously published geological and archaeological reports, historical texts, together with new optically stimulated luminescence (OSL) ages and stratigraphic and sedimentological data are analyzed. The deposition, mobilizations and preservation of the sand bodies, initially induced by the decline in sea level rise at 6-4 ka, were later controlled by historic land-use intensity and modern land-use/negligence practices. At 6 ka, beach sand buildup rapidly started. Where aeolianite ridges bordered the coast, pulses of sand with biogenic carbonate grains unconformably draped the ridges and rapidly consolidated into a distinct sandy calcarenite unit. Further east, sand sheets and low dunes partly pedogenized following their incursion, but did not cement. The water retention capacities of the sand sheets enabled the establishment of a sand-stabilizing vegetation cover that probably became an attractive environment for fuel and grazing. The growing Hellenistic-Roman-Byzantine ( 2.4-1.3 ka) populations probably led to increased consumption and massive destruction of sand stabilizing vegetation, enabling sand erodibility and mobilization during winter storms. The sand

  7. Sand and Gravel Deposits

    Data.gov (United States)

    Vermont Center for Geographic Information — This dataset is a statewide polygon coverage of sand, gravel, and stone resources. This database includes the best data available from the VT Agency of Natural...

  8. Sand and Gravel Operations

    Data.gov (United States)

    Department of Homeland Security — This map layer includes sand and gravel operations in the United States. These data were obtained from information reported voluntarily to the USGS by the aggregate...

  9. Retorting of bituminous sands

    Energy Technology Data Exchange (ETDEWEB)

    Chaney, P E; Ince, R W; Mason, C M

    1872-09-26

    This method of recovering oil from mined tar sands involves forming compacted tar sands pieces by special conditioning treatment that provides low internal permeability. The compacted pieces are then retorted in fixed bed form. The conditioning treatment can involve rolling of preformed pellets, compaction in a mold or pressure extrusion. Substantial collapsing of the bed during retorting is avoided. (9 claims) (Abstract only - original article not available from T.U.)

  10. MECHANICAL REGENERATION OF SAND WASTE

    Directory of Open Access Journals (Sweden)

    D. I. Gnir

    2005-01-01

    Full Text Available The experimental activation of the sand regenerator of the firm SINTO is carried out at ОАО “MZOO". It is shown that sand grains are cleared from films of binding agents, that allows to use the treated sand for preparation of agglutinant and core sands.

  11. Revegetation and management of tailings sand slopes from tar sand extraction: 1978 results

    Energy Technology Data Exchange (ETDEWEB)

    Rowell, M J

    1979-01-01

    The results are reported of research into the revegetation of two areas on a steeply sloping dike composed of tailings sand from tar sand extraction at the Great Canadian Oil Sand Limited plant at Fort McMurray, Alberta. One area was seeded with three pasture grasses and two legumes in 1971 after the slope surface had been mixed with peat to a depth of 15 cm. A second area had been amended with peat or peat and overburden and differing rates of fertilizer added. A mix containing nine grasses, four legumes, and oats, as a companion crop, was seeded in July 1976. The objectives of the research were to study methods for the establishment of a stable vegetative cover that would prevent erosion of the slope and, in time, might become a self maintaining unit. Tillage of soil amendments to a depth of 15 cm and 30 cm were compared in promoting deeper rooting and stabilizing of the slope.

  12. Seasonal soil CO2 flux under big sagebrush (Artemisia tridentata Nutt.)

    Science.gov (United States)

    Michael C. Amacher; Cheryl L. Mackowiak

    2011-01-01

    Soil respiration is a major contributor to atmospheric CO2, but accurate landscape-scale estimates of soil CO2 flux for many ecosystems including shrublands have yet to be established. We began a project to measure, with high spatial and temporal resolution, soil CO2 flux in a stand (11 x 25 m area) of big sagebrush (Artemisia tridentata Nutt.) at the Logan, Utah,...

  13. Restoration handbook for sagebrush steppe ecosystems with emphasis on greater sage-grouse habitat—Part 1. Concepts for understanding and applying restoration

    Science.gov (United States)

    Pyke, David A.; Chambers, Jeanne C.; Pellant, Mike; Knick, Steven T.; Miller, Richard F.; Beck, Jeffrey L.; Doescher, Paul S.; Schupp, Eugene W.; Roundy, Bruce A.; Brunson, Mark; McIver, James D.

    2015-10-26

    Sagebrush steppe ecosystems in the United States currently occur on only about one-half of their historical land area because of changes in land use, urban growth, and degradation of land, including invasions of non-native plants. The existence of many animal species depends on the existence of sagebrush steppe habitat. The greater sage-grouse (Centrocercus urophasianus) is a landscape-dependent bird that requires intact habitat and combinations of sagebrush and perennial grasses to exist. In addition, other sagebrush-obligate animals also have similar requirements and restoration of landscapes for greater sage-grouse also will benefit these animals. Once sagebrush lands are degraded, they may require restoration actions to make those lands viable habitat for supporting sagebrushobligate animals. This restoration handbook is the first in a three-part series on restoration of sagebrush ecosystems. In Part 1, we discuss concepts surrounding landscape and restoration ecology of sagebrush ecosystems and greater sage-grouse that habitat managers and restoration practitioners need to know to make informed decisions regarding where and how to restore specific areas. We will describe the plant dynamics of sagebrush steppe ecosystems and their responses to major disturbances, fire, and defoliation. We will introduce the concepts of ecosystem resilience to disturbances and resistance to invasions of annual grasses within sagebrush steppe. An introduction to soils and ecological site information will provide insights into the specific plants that can be restored in a location. Soil temperature and moisture regimes are described as a tool for determining resilience and resistance and the potential for various restoration actions. Greater sage-grouse are considered landscape birds that require large areas of intact sagebrush steppe; therefore, we describe concepts of landscape ecology that aid our decisions regarding habitat restoration. We provide a brief overview of

  14. Oil sands tax expenditures

    International Nuclear Information System (INIS)

    Ketchum, K; Lavigne, R.; Plummer, R.

    2001-01-01

    The oil sands are a strategic Canadian resource for which federal and provincial governments provide financial incentives to develop and exploit. This report describes the Oil Sands Tax Expenditure Model (OSTEM) developed to estimate the size of the federal income tax expenditure attributed to the oil sands industry. Tax expenditures are tax concessions which are used as alternatives to direct government spending for achieving government policy objectives. The OSTEM was developed within the business Income Tax Division of Canada's Department of Finance. Data inputs for the model were obtained from oil sands developers and Natural Resources Canada. OSTEM calculates annual revenues, royalties and federal taxes at project levels using project-level projections of capital investment, operating expenses and production. OSTEM calculates tax expenditures by comparing taxes paid under different tax regimes. The model also estimates the foregone revenue as a percentage of capital investment. Total tax expenditures associated with investment in the oil sands are projected to total $820 million for the period from 1986 to 2030, representing 4.6 per cent of the total investment. 10 refs., 2 tabs., 7 figs

  15. Bituminous sands : tax issues

    International Nuclear Information System (INIS)

    Patel, B.

    2004-01-01

    This paper examined some of the tax issues associated with the production of bitumen or synthetic crude oil from oil sands. The oil sands deposits in Alberta are gaining more attention as the supplies of conventional oil in Canada decline. The oil sands reserves located in the Athabasca, Cold Lake and Peace River areas contain about 2.5 trillion barrels of highly viscous hydrocarbons called bitumen, of which nearly 315 billion barrels are recoverable with current technology. The extraction method varies for each geographic area, and even within zones and reservoirs. The two most common extraction methods are surface mining and in-situ extraction such as cyclic steam stimulation (CSS); low pressure steam flood; pressure cycle steam drive; steam assisted gravity drainage (SAGD); hot water flooding; and, fire flood. This paper also discussed the following general tax issues: bituminous sands definition; bituminous sands leases and Canadian development expense versus Canadian oil and gas property expense (COGPE); Canadian exploration expense (CEE) for surface mining versus in-situ methods; additional capital cost allowance; and, scientific research and experimental development (SR and ED). 15 refs

  16. Response of bird community structure to habitat management in piñon-juniper woodland-sagebrush ecotones

    Science.gov (United States)

    Knick, Steven T.; Hanser, Steven E.; Grace, James B.; Hollenbeck, Jeff P.; Leu, Matthias

    2017-01-01

    Piñon (Pinus spp.) and juniper (Juniperus spp.) woodlands have been expanding their range across the intermountain western United States into landscapes dominated by sagebrush (Artemisia spp.) shrublands. Management actions using prescribed fire and mechanical cutting to reduce woodland cover and control expansion provided opportunities to understand how environmental structure and changes due to these treatments influence bird communities in piñon-juniper systems. We surveyed 43 species of birds and measured vegetation for 1–3 years prior to treatment and 6–7 years post-treatment at 13 locations across Oregon, California, Idaho, Nevada, and Utah. We used structural equation modeling to develop and statistically test our conceptual model that the current bird assembly at a site is structured primarily by the previous bird community with additional drivers from current and surrounding habitat conditions as well as external regional bird dynamics. Treatment reduced woodland cover by >5% at 80 of 378 survey sites. However, habitat change achieved by treatment was highly variable because actual disturbance differed widely in extent and intensity. Biological inertia in the bird community was the strongest single driver; 72% of the variation in the bird assemblage was explained by the community that existed seven years earlier. Greater net reduction in woodlands resulted in slight shifts in the bird community to one having ecotone or shrubland affinities. However, the overall influence of woodland changes from treatment were relatively small and were buffered by other extrinsic factors. Regional bird dynamics did not significantly influence the structure of local bird communities at our sites. Our results suggest that bird communities in piñon-juniper woodlands can be highly stable when management treatments are conducted in areas with more advanced woodland development and at the level of disturbance measured in our study.

  17. Ecologia do forrageio por Cyphomyrmex morschi Emery (Hymenoptera, Formicidae em vegetação de restinga no Sul do Brasil Foraging ecology of Cyphomyrmex morschi Emery (Hymenoptera, Formicidae in sand dune vegetation at Southern Brazil

    Directory of Open Access Journals (Sweden)

    Benedito Cortês Lopes

    2007-03-01

    Full Text Available Foram amostrados 400 ninhos de Cyphomyrmex morschi Emery, 1887 entre 1997 e 1998, nas dunas da praia da Joaquina, Florianópolis, SC, para a verificação do material transportado ao ninho. Estas formigas utilizam material de origem vegetal ou animal (fezes de lagartas de Lepidoptera ou partes de corpos de besouros ou formigas ou mesmo material não identificado que são introduzidos no ninho para o cultivo do fungo. Assim, do ponto de vista do papel ecológico desempenhado, pode-se considerar C. morschi como uma espécie detritófaga.A total of 400 nests of Cyphomyrmex morschi Emery, 1887 was evaluated between 1997 and 1998 at the dunes of the Joaquina Beach, Florianópolis, Santa Catarina, in order to verify the substrate brought back to the nests. These ants use vegetable or animal material (excrements of lepidopteran larvae or carcasses of beetles or ants or even not identified material that are used to culture the fungus. Thus, ecologically speaking, C. morschi can be considered a detritiphagous species.

  18. Demography and monitoring of Welsh's milkweed (Asclepias welshii) at Coral Pink Sand Dunes

    Science.gov (United States)

    Brent C. Palmer; L. Armstrong

    2001-01-01

    Results are presented of a 12-year monitoring program on the Coral Pink Sand Dunes and Sand Hills populations of the threatened Welsh's milkweed, Asclepias welshii N & P Holmgren. The species is an early sera1 member of the dune flora, colonizing blowouts and advancing with shifting dunes. When an area stabilizes and other vegetation encroaches, A. welshii is...

  19. Sand Dunes with Frost

    Science.gov (United States)

    2004-01-01

    9 May 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a suite of frost-covered sand dunes in the north polar region of Mars in early spring, 2004. The dunes indicate wind transport of sand from left to right (west to east). These landforms are located near 78.1oN, 220.8oW. This picture is illuminated by sunlight from the lower left and covers an area about 3 km (1.9 mi) across.

  20. Big sagebrush in pinyon-juniper woodlands: Using forest inventory and analysis data as a management tool for quantifying and monitoring mule deer habitat

    Science.gov (United States)

    Chris Witt; Paul L. Patterson

    2011-01-01

    We used Interior West Forest Inventory and Analysis (IW-FIA) data to identify conditions where pinyon-juniper woodlands provide security cover, thermal cover, and suitable amounts of big sagebrush (Artemisia tridentata spp.) forage to mule deer in Utah. Roughly one quarter of Utah's pinyon-juniper woodlands had a big sagebrush component in their understory....

  1. Narrow hybrid zone between two subspecies of big sagebrush (Artemisia tridentata: Asteraceae): XI. Plant-insect interactions in reciprocal transplant gardens

    Science.gov (United States)

    John H. Graham; E. Durant McArthur; D. Carl Freeman

    2001-01-01

    Basin big sagebrush (Artemisia tridentata ssp. tridentata) and mountain big sagebrush (A. t. ssp. vaseyana) hybridize in a narrow zone near Salt Creek, Utah. Reciprocal transplant experiments in this hybrid zone demonstrate that hybrids are more fit than either parental subspecies, but only in the hybrid zone. Do hybrids experience greater, or lesser, use by...

  2. A seasonal comparison of deposition velocities and retention half-times for Cs-134 and Ce-141 on cool desert vegetation

    International Nuclear Information System (INIS)

    Millard, Gloria C.; Fraley, Leslie Jr.; Markham, O.D.

    1978-01-01

    Due to a scarcity of reliable deposition velocity estimates for radionuclides (particularly those in the submicron range) pooled estimates have been used to predict population doses resulting from atmospheric releases of radioactive particulates. The use of these estimates has led to large uncertainties in whole body dose estimates. Deposition velocities and retention half-times were therefore determined for submicron aerosols of 141 Ce (biologically inactive) and 134 Cs (biologically active) on sagebrush dominated desert vegetation in SE Idaho. Approximately 250 mCi (9.3 GBq) of each radionuclide were released over stands of Artemisia tridentata (big sagebrush) and bottlebrush grass (Sitanion hystrix) during three stages of plant development - spring vegetative growth, seed development, and plant dormancy. Air filters and vegetation samples were collected immediately following each release for use in deposition velocity calculations. Vegetation sampling was continued for a period of three months to obtain retention data. Deposition velocity values were 0.20 cm/s for sagebrush and 0.025 cm/s for grass. The loss of activity on the vegetation seemed to best fit a two component exponential loss function. Short component half-times were 1 to 2 days for both species. Long component half-times were two to three weeks for the shrub species and one to two weeks for the grass species. No significant difference was observed between nuclides. (author)

  3. W-519 Sagebrush Mitigation Project FY-2004 Final Review and Status

    Energy Technology Data Exchange (ETDEWEB)

    Durham, Robin E.; Sackschewsky, Michael R.

    2004-09-30

    This report summarizes activities conducted as mitigation for loss of sagebrush-steppe habitats due to Project W-519, the construction of the infrastructure for the Tank Waste Remediation System Vitrification Plant. The focus of this report is to provide a review and final status of mitigation actions performed through FY2004. Data collected since FY1999 have been included where appropriate. The Mitigation Action Plan (MAP) for Project W-519 prescribed three general actions to be performed as mitigation for the disturbance of approximately 40 ha (100 acres) of mature sagebrush-steppe habitat. These actions included: (1) transplanting approximately 130,000 sagebrush seedlings on the Fitzner-Eberhardt Arid Lands Ecology Reserve (ALE); (2) rectification of the new transmission line corridor via seeding with native grasses and sagebrush; and (3) research on native plant species with a goal of increasing species diversity in future mitigation or restoration actions. Nearly 130,000 Wyoming big sagebrush seedlings where planted on ALE during FY2000 and FY2001. About 39,000 of those seedlings were burned during the 24-Command Fire of June 2000. The surviving and subsequent replanting has resulted in about 91,000 seedlings that were planted across four general areas on ALE. A 50% survival rate at any monitoring period was defined as the performance standard in the MAP for this project. Data collected in 2004 indicate that of the over 5000 monitored plants, 51.1% are still alive, and of those the majority are thriving and blooming. These results support the potential for natural recruitment and the ultimate goal of wildlife habitat replacement. Thus, the basic performance standard for sagebrush survival within the habitat compensation planting has been met. Monitoring activities conducted in 2004 indicate considerable variation in seedling survival depending on the type of plant material, site conditions, and to a lesser extent, treatments performed at the time of planting

  4. W-519 Sagebrush Mitigation Project FY-2004 Final Review and Status

    International Nuclear Information System (INIS)

    Durham, Robin E.; Sackschewsky, Michael R.

    2004-01-01

    This report/SUMmarizes activities conducted as mitigation for loss of sagebrush-steppe habitats due to Project W-519, the construction of the infrastructure for the Tank Waste Remediation System Vitrification Plant. The focus of this report is to provide a review and final status of mitigation actions performed through FY2004. Data collected since FY1999 have been included where appropriate. The Mitigation Action Plan (MAP) for Project W-519 prescribed three general actions to be performed as mitigation for the disturbance of approximately 40 ha (100 acres) of mature sagebrush-steppe habitat. These actions included: (1) transplanting approximately 130,000 sagebrush seedlings on the Fitzner-Eberhardt Arid Lands Ecology Reserve (ALE); (2) rectification of the new transmission line corridor via seeding with native grasses and sagebrush; and (3) research on native plant species with a goal of increasing species diversity in future mitigation or restoration actions. Nearly 130,000 Wyoming big sagebrush seedlings where planted on ALE during FY2000 and FY2001. About 39,000 of those seedlings were burned during the 24-Command Fire of June 2000. The surviving and subsequent replanting has resulted in about 91,000 seedlings that were planted across four general areas on ALE. A 50% survival rate at any monitoring period was defined as the performance standard in the MAP for this project. Data collected in 2004 indicate that of the over 5000 monitored plants, 51.1% are still alive, and of those the majority are thriving and blooming. These results support the potential for natural recruitment and the ultimate goal of wildlife habitat replacement. Thus, the basic performance standard for sagebrush survival within the habitat compensation planting has been met. Monitoring activities conducted in 2004 indicate considerable variation in seedling survival depending on the type of plant material, site conditions, and to a lesser extent, treatments performed at the time of planting

  5. Sand (CSW4)

    CSIR Research Space (South Africa)

    Estuarine and Coastal Research Unit

    1982-12-01

    Full Text Available This report is one of a series on Cape Estuaries being published under the general title "The Estuaries of the Cape, Part 2". The report provides information on sand estuary: historical background, abiotic and biotic characteristics. It is pointed...

  6. Inland drift sand landscapes

    NARCIS (Netherlands)

    Fanta, J.; Siepel, H.

    2010-01-01

    Man has had a complex relationship with inland drift sands through the ages. For some centuries these landscapes were seen as a threat to society, especially agriculture and housing. At present we conserve these landscapes as important Natura 2000 priority habitats. In this book you may find these

  7. On Pluvial Compaction of Sand

    DEFF Research Database (Denmark)

    Jacobsen, Moust

    At the Institute of Civil Engineering in Aalborg model tests on dry sand specimens have been carried out during the last five years. To reduce deviations in test results, the sand laying technique has been carefully studied, and the sand mass spreader constructed. Preliminary results have been...

  8. Multi-scale remote sensing sagebrush characterization with regression trees over Wyoming, USA: laying a foundation for monitoring

    Science.gov (United States)

    Homer, Collin G.; Aldridge, Cameron L.; Meyer, Debra K.; Schell, Spencer J.

    2012-01-01

    agebrush ecosystems in North America have experienced extensive degradation since European settlement. Further degradation continues from exotic invasive plants, altered fire frequency, intensive grazing practices, oil and gas development, and climate change – adding urgency to the need for ecosystem-wide understanding. Remote sensing is often identified as a key information source to facilitate ecosystem-wide characterization, monitoring, and analysis; however, approaches that characterize sagebrush with sufficient and accurate local detail across large enough areas to support this paradigm are unavailable. We describe the development of a new remote sensing sagebrush characterization approach for the state of Wyoming, U.S.A. This approach integrates 2.4 m QuickBird, 30 m Landsat TM, and 56 m AWiFS imagery into the characterization of four primary continuous field components including percent bare ground, percent herbaceous cover, percent litter, and percent shrub, and four secondary components including percent sagebrush (Artemisia spp.), percent big sagebrush (Artemisia tridentata), percent Wyoming sagebrush (Artemisia tridentata Wyomingensis), and shrub height using a regression tree. According to an independent accuracy assessment, primary component root mean square error (RMSE) values ranged from 4.90 to 10.16 for 2.4 m QuickBird, 6.01 to 15.54 for 30 m Landsat, and 6.97 to 16.14 for 56 m AWiFS. Shrub and herbaceous components outperformed the current data standard called LANDFIRE, with a shrub RMSE value of 6.04 versus 12.64 and a herbaceous component RMSE value of 12.89 versus 14.63. This approach offers new advancements in sagebrush characterization from remote sensing and provides a foundation to quantitatively monitor these components into the future.

  9. Environmental Impacts of Sand Exploitation. Analysis of Sand Market

    Directory of Open Access Journals (Sweden)

    Marius Dan Gavriletea

    2017-06-01

    Full Text Available Sand is an indispensable natural resource for any society. Despite society’s increasing dependence on sand, there are major challenges that this industry needs to deal with: limited sand resources, illegal mining, and environmental impact of sand mining. The purpose of this paper is twofold: to present an overview of the sand market, highlighting the main trends and actors for production, export and import, and to review the main environmental impacts associated with sand exploitation process. Based on these findings, we recommend different measures to be followed to reduce negative impacts. Sand mining should be done in a way that limits environmental damage during exploitation and restores the land after mining operations are completed.

  10. Mapping SOC (Soil Organic Carbon) using LiDAR-derived vegetation indices in a random forest regression model

    Science.gov (United States)

    Will, R. M.; Glenn, N. F.; Benner, S. G.; Pierce, J. L.; Spaete, L.; Li, A.

    2015-12-01

    Quantifying SOC (Soil Organic Carbon) storage in complex terrain is challenging due to high spatial variability. Generally, the challenge is met by transforming point data to the entire landscape using surrogate, spatially-distributed, variables like elevation or precipitation. In many ecosystems, remotely sensed information on above-ground vegetation (e.g. NDVI) is a good predictor of below-ground carbon stocks. In this project, we are attempting to improve this predictive method by incorporating LiDAR-derived vegetation indices. LiDAR provides a mechanism for improved characterization of aboveground vegetation by providing structural parameters such as vegetation height and biomass. In this study, a random forest model is used to predict SOC using a suite of LiDAR-derived vegetation indices as predictor variables. The Reynolds Creek Experimental Watershed (RCEW) is an ideal location for a study of this type since it encompasses a strong elevation/precipitation gradient that supports lower biomass sagebrush ecosystems at low elevations and forests with more biomass at higher elevations. Sagebrush ecosystems composed of Wyoming, Low and Mountain Sagebrush have SOC values ranging from .4 to 1% (top 30 cm), while higher biomass ecosystems composed of aspen, juniper and fir have SOC values approaching 4% (top 30 cm). Large differences in SOC have been observed between canopy and interspace locations and high resolution vegetation information is likely to explain plot scale variability in SOC. Mapping of the SOC reservoir will help identify underlying controls on SOC distribution and provide insight into which processes are most important in determining SOC in semi-arid mountainous regions. In addition, airborne LiDAR has the potential to characterize vegetation communities at a high resolution and could be a tool for improving estimates of SOC at larger scales.

  11. Intermontane eolian sand sheet development, Upper Tulum Valley, central-western Argentina

    Directory of Open Access Journals (Sweden)

    Patrick Francisco Fuhr Dal' Bó

    Full Text Available ABSTRACTThe intermontane Upper Tulum eolian sand sheet covers an area of ca. 125 km² at north of the San Juan Province, central-western Argentina. The sand sheet is currently an aggrading system where vegetation cover, surface cementation and periodic flooding withhold the development of dunes with slipfaces. The sand sheet surface is divided into three parts according to the distribution of sedimentary features, which reflects the variation in sediment budget, water table level and periodic flooding. The central sand sheet part is the main area of eolian deposition and is largely stabilized by vegetation. The sedimentary succession is 4 m thick and records the vertical interbedding of eolian and subaqueous deposits, which have been deposited for at least 3.6 ky with sedimentation rates of 86.1 cm/ky. The construction of the sand sheet is associated with deflation of the sand-graded debris sourced by San Juan alluvial fan, which is available mainly in drier fall-winter months where water table is lower and wind speeds are periodically above the threshold velocity for sand transport. The accumulation of sedimentary bodies occurs in a stabilized eolian system where vegetation cover, thin mud veneers and surface cementation are the main agents in promoting accumulation. The preservation of the sand sheet accumulations is enabled by the progressive creation of the accommodation space in a tectonically active basin and the continuous burial of geological bodies favored by high rates of sedimentation.

  12. Integrated disposal Facility Sagebrush Habitat Mitigation Project: FY2007 Compensation Area Monitoring Report

    Energy Technology Data Exchange (ETDEWEB)

    Durham, Robin E.; Sackschewsky, Michael R.

    2007-09-01

    This report summarizes the first year survival of sagebrush seedlings planted as compensatory mitigation for the Integrated Disposal Facility Project. Approximately 42,600 bare root seedlings and 26,000 pluglings were planted at a mitigation site along Army Loop Road in February 2007. Initial baseline monitoring occurred in March 2007, and first summer survival was assessed in September 2007. Overall survival was 19%, with bare root survival being marginally better than pluglings (21% versus 14%). Likely major factors contributing to low survival were late season planting and insufficient soil moisture during seedling establishment.

  13. Oil sands supply outlook

    International Nuclear Information System (INIS)

    Dunbar, R.

    2004-01-01

    In March 2004, The Canadian Energy Research Institute released a report on the expected future supply from Alberta's oil sands. The report indicates that the future for the already well-established oil sands industry is promising, particularly given the outlook for oil prices. The challenges facing the industry include higher industry supply costs and the need for innovative commercial and technological solutions to address the risks of irregularities and changes in crude oil prices. In 2003, the industry produced 874 thousand barrels per day of synthetic crude oil and unprocessed crude bitumen. This represents 35 per cent of Canada's total oil production. Current production capacity has increased to 1.0 million barrels per day (mbpd) due to new projects. This number may increase to 3.5 mbpd by 2017. Some new projects may be deferred due to the higher raw bitumen and synthetic crude oil supply costs. This presentation provided supply costs for a range of oil sands recovery technologies and production projections under various business scenarios. tabs., figs

  14. Liquefaction resistance of calcareous sands

    International Nuclear Information System (INIS)

    Sandoval Vallejo, Eimar

    2012-01-01

    Calcareous sands are unique in terms of their origin, mineralogy, shape, fragility and intra particle porosity. This article presents results from an experimental program carried out to study the liquefaction resistance of a calcareous sand retrieved from Cabo Rojo at Puerto Rico. The experimental program included mineralogical characterization, index properties, and undrained cyclic triaxial tests on isotropically consolidated reconstituted samples. Due to the large variation in the calcareous sand properties, results are compared with previous researches carried out on other calcareous sands around the world. Results showed a wide range in the liquefaction resistance of the studied calcareous sands. Cabo Rojo sand experienced greater liquefaction resistance than most of the calcareous sands used for comparison. Important differences in the excess pore pressure generation characteristics were also found.

  15. Booming Sand Dunes

    Science.gov (United States)

    Vriend, Nathalie

    "Booming" sand dunes are able to produce low-frequency sound that resembles a pure note from a music instrument. The sound has a dominant audible frequency (70-105 Hz) and several higher harmonics and may be heard from far distances away. A natural or induced avalanche from a slip face of the booming dune triggers the emission that may last for several minutes. There are various references in travel literature to the phenomenon, but to date no scientific explanation covered all field observations. This thesis introduces a new physical model that describes the phenomenon of booming dunes. The waveguide model explains the selection of the booming frequency and the amplification of the sound in terms of constructive interference in a confined geometry. The frequency of the booming is a direct function of the dimensions and velocities in the waveguide. The higher harmonics are related to the higher modes of propagation in the waveguide. The experimental validation includes quantitative field research at the booming dunes of the Mojave Desert and Death Valley National Park. Microphone and geophone recordings of the acoustic and seismic emission show a variation of booming frequency in space and time. The analysis of the sensor data quantifies wave propagation characteristics such as speed, dispersion, and nonlinear effects and allows the distinction between the source mechanism of the booming and the booming itself. The migration of sand dunes results from a complicated interplay between dune building, wind regime, and precipitation. The morphological and morphodynamical characteristics of two field locations are analyzed with various geophysical techniques. Ground-penetrating radar images the subsurface structure of the dunes and reveal a natural, internal layering that is directly related to the history of dune migration. The seismic velocity increases abruptly with depth and gradually increases with downhill position due to compaction. Sand sampling shows local

  16. History of fire and Douglas-fir establishment in a savanna and sagebrush-grassland mosaic, southwestern Montana, USA

    Science.gov (United States)

    Emily K. Heyerdahl; Richard F. Miller; Russell A. Parsons

    2006-01-01

    Over the past century, trees have encroached into grass- and shrublands across western North America. These include Douglas-fir trees (Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco) encroaching into mountain big sagebrush Nutt. ssp. vaseyana (Rydb.) Beetle) from stable islands of savanna in...

  17. Conservation and restoration of sagebrush ecosystems and sage-grouse: An assessment of USDA Forest Service Science

    Science.gov (United States)

    Deborah M. Finch; Douglas A. Boyce; Jeanne C. Chambers; Chris J. Colt; Kas Dumroese; Stanley G. Kitchen; Clinton McCarthy; Susan E. Meyer; Bryce A. Richardson; Mary M. Rowland; Mark A. Rumble; Michael K. Schwartz; Monica S. Tomosy; Michael J. Wisdom

    2016-01-01

    Sagebrush ecosystems are among the largest and most threatened ecosystems in North America. Greater sage-grouse has served as the bellwether for species conservation in these ecosystems and has been considered for listing under the Endangered Species Act eight times. In September 2015, the decision was made not to list greater sage-grouse, but to reevaluate its status...

  18. Evolutionary and ecological implications of genome size in the North American endemic sagebrushes and allies (Artemisia, Asteraceae)

    Science.gov (United States)

    Sonia Garcia; Miguel A. Canela; Teresa Garnatje; E. Durant McArthur; Jaume Pellicer; Stewart C. Sanderson; Joan Valles

    2008-01-01

    The genome size of 51 populations of 20 species of the North American endemic sagebrushes (subgenus Tridentatae), related species, and some hybrid taxa were assessed by flow cytometry, and were analysed in a phylogenetic framework. Results were similar for most Tridentatae species, with the exception of three taxonomically conflictive species: Artemisia bigelovii Gray...

  19. Plant age, communication, and resistance to herbivores: young sagebrush plants are better emitters and receivers.

    Science.gov (United States)

    Shiojiri, Kaori; Karban, Richard

    2006-08-01

    Plants progress through a series of distinct stages during development, although the role of plant ontogeny in their defenses against herbivores is poorly understood. Recent work indicates that many plants activate systemic induced resistance after herbivore attack, although the relationship between resistance and ontogeny has not been a focus of this work. In addition, for sagebrush and a few other species, individuals near neighbors that experience simulated herbivory become more resistant to subsequent attack. Volatile, airborne cues are required for both systemic induced resistance among branches and for communication among individuals. We conducted experiments in stands of sagebrush of mixed ages to determine effects of plant age on volatile signaling between branches and individuals. Young and old control plants did not differ in levels of chewing damage that they experienced. Systemic induced resistance among branches was only observed for young plants. Young plants showed strong evidence of systemic resistance only if airflow was permitted among branches; plants with only vascular connections showed no systemic resistance. We also found evidence for volatile communication between individuals. For airborne communication, young plants were more effective emitters of cues as well as more responsive receivers of volatile cues.

  20. Oil sands development update

    International Nuclear Information System (INIS)

    1999-01-01

    A detailed review and update of oil sands development in Alberta are provided covering every aspect of the production and economic aspects of the industry. It is pointed out that at present oil sands account for 28 per cent of Canadian crude oil production, expected to reach 50 per cent by 2005. Based on recent announcements, a total of 26 billion dollars worth of projects are in progress or planned; 20 billion dollars worth of this development is in the Athabasca area, the remainder in Cold Lake and other areas. The current update envisages up to 1,800,000 barrels per day by 2008, creating 47,000 new jobs and total government revenues through direct and indirect taxes of 118 billion dollars. Provinces other than Alberta also benefit from these development, since 60 per cent of all employment and income created by oil sands production is in other parts of Canada. Up to 60 per cent of the expansion is for goods and services and of this, 50 to 55 per cent will be purchased from Canadian sources. The remaining 40 per cent of the new investment is for engineering and construction of which 95 per cent is Canadian content. Aboriginal workforce by common consent of existing operators matches regional representation (about 13 per cent), and new developers are expected to match these standards. Planned or ongoing development in environmental protection through improved technologies and optimization, energy efficiency and improved tailings management, and active support of flexibility mechanisms such as emission credits trading, joint implementation and carbon sinks are very high on the industry's agenda. The importance of offsets are discussed extensively along with key considerations for international negotiations, as well as further research of other options such as sequestration, environmentally benign disposal of waste, and enhanced voluntary action

  1. Compressive behavior of fine sand.

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Bradley E. (Air Force Research Laboratory, Eglin, FL); Kabir, Md. E. (Purdue University, West Lafayette, IN); Song, Bo; Chen, Wayne (Purdue University, West Lafayette, IN)

    2010-04-01

    The compressive mechanical response of fine sand is experimentally investigated. The strain rate, initial density, stress state, and moisture level are systematically varied. A Kolsky bar was modified to obtain uniaxial and triaxial compressive response at high strain rates. A controlled loading pulse allows the specimen to acquire stress equilibrium and constant strain-rates. The results show that the compressive response of the fine sand is not sensitive to strain rate under the loading conditions in this study, but significantly dependent on the moisture content, initial density and lateral confinement. Partially saturated sand is more compliant than dry sand. Similar trends were reported in the quasi-static regime for experiments conducted at comparable specimen conditions. The sand becomes stiffer as initial density and/or confinement pressure increases. The sand particle size become smaller after hydrostatic pressure and further smaller after dynamic axial loading.

  2. Reclamation and closure of an oil sands tailings facility

    Energy Technology Data Exchange (ETDEWEB)

    Sobkowicz, J. [Thurber Engineering Ltd., Calgary, AB (Canada); Morgenstern, N. [Alberta Univ., Edmonton, AB (Canada)

    2010-07-01

    This PowerPoint presentation discussed methods of ensuring the successful reclamation of oil sands tailings facilities. Tailings should be reclaimed as mining proceeds in order to avoid an excessive accumulation of fluid fine tailings (FFT). The volume of mature fine tailings (MFT) in ponds should be limited in order to ensure effective tailings management. The reclaimed landforms should have good geotechnical stability and be comprised of self-sustaining native vegetation. Strength is needed to allow for timely capping and initial reclamation, and stiffness is required to minimize future settlement and to allow for the construction of a closure landscape. Reclamation strategies were presented for fines-dominated tailings; sand-depleted tailings; and sand-dominated tailings. Energy Resources Conservation Board (ERCB) criteria for tailings reclamation were discussed, and various monitoring and performance assessment strategies were presented. tabs., figs.

  3. Rheological Characterization of Green Sand Flow

    DEFF Research Database (Denmark)

    Jabbaribehnam, Mirmasoud; Spangenberg, Jon; Hovad, Emil

    2016-01-01

    The main aim of this paper is to characterize experimentally the flow behaviour of the green sand that is used for casting of sand moulds. After the sand casting process is performed, the sand moulds are used for metal castings. The rheological properties of the green sand is important to quantif...

  4. Sand, jams and jets

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, H. [James Franck Institute and Department of Physics, University of Chicago (United States)]. E-mail: h-jaeger@uchicago.edu

    2005-12-01

    Granular media are offering new insights into problems in condensed-matter physics and materials science, as Heinrich Jaeger explains. The remarkable properties of granular materials are so familiar that most of us do not even notice them. It is clear, for example, that we cannot walk on water unless the temperature has dropped below freezing. However, we take it for granted that sand will support our weight as if it were a solid, even though it can also be poured like a liquid under the same ambient conditions. From breakfast cereal, sugar and flour to construction materials, mining products and pharmaceuticals, granular media are present everywhere in our daily lives. (U.K.)

  5. Riddle of the sands

    Energy Technology Data Exchange (ETDEWEB)

    Rolheiser, P

    1998-09-01

    A geological model of the Alberta landscape during the period stretching from about 110 million to 100 million years ago during the Cretaceous period when dinosaurs roamed the earth, was sketched. Today, the region contains the Cold Lake oil sands deposit. Imperial Oil began large-scale production at Cold Lake in 1985. The formations within the area are the source of almost half of Imperial Oil`s daily crude oil production and account for one in every 20 barrels of oil produced daily in Canada. The bitumen is produced using cyclic steam stimulation where steam is injected at high pressure into the underground reservoir, fracturing the sandstone and heating the bitumen it holds to thin it so that it can then flow through well bores to the surface. Conventional geological theory suggested that the Cold Lake reservoir was the remains of a prehistoric river delta. In 1994, Imperial Oil established a Cold Lake sequence stratigraphy project to verify this theory. This highly complex project involves volumes of geophysical well-log data from the 2,500 wells at Cold Lake, core samples cut from more than 600 of these wells and microscopic fossilized remains of 100-million-year-old flora extracted from the core samples, and seismic information. The interpreted data helps to create a three-dimensional model of the reservoir`s structure and help define its boundaries. Results have shown that the Cold Lake deposit was created from at least 13 intersecting river beds. Each of the rivers flowed for a few hundred thousand years and deposited sands of varying quality in different layers and patterns. The oil came about 40 million years later after the plant and animal materials containing hydrogen and carbon were broken down by heat and pressure to form oil. 1 fig.

  6. Investigation of Great Basin big sagebrush and black greasewood as biogeochemical indicators of uranium mineralization. Final report. National Uranium Resource Evaluation

    International Nuclear Information System (INIS)

    Diebold, F.E.; McGrath, S.

    1982-11-01

    The effects of varying phosphate concentrations in natural aqueous systems upon the uptake of uranium by big sagebrush (Artemesia tridentata subsp. tridentata) and black greasewood (Sarcobatus vermiculatus (Hook) Torr.) were investigated. Two separate growth experiments with five drip-flow hyroponic units were used and plant seedlings were grown for 60 days in solutions of varying phosphate and uranium concentrations. Successful growth experiments were obtained only for big sagebrush; black greasewood did not sustain sufficient growth. The phosphate concentration of the water did affect the uptake of uranium by the big sagebrush, and this effect is most pronounced in the region of higher concentrations of uranium in the water. The ratio of the concentration of uranium in the plant to that in the water was observed to decrease with increasing uranium concentration in solution. This is indicative of an absorption barrier in the plants. The field data shows that big sagebrush responds to uranium concentrations in the soil water and not the groundwater. The manifestation of these results is that the use of big sagebrush as a biogeochemical indicator of uranium is not recommended. Since the concentration of phosphate must also be knwon in the water supplying the uranium to the plant, one should analyze this natural aqueous phase as a hydrochemical indicator rather than the big sagebrush

  7. The Alberta oil sands story

    Energy Technology Data Exchange (ETDEWEB)

    1974-01-01

    This report serves as a detailed introduction to the Alberta oil sands and their development. It includes a description of the oil sands deposits, an outline of crude bitumen recovery and upgrading processes, the role of Alberta Energy Company in oil sands development, environmental aspects, manpower requirements for oil sands development, research needs, and further oil sands projects. Presently proven recoverable reserves in the oil sands amount to 26.5 billion bbl of synthetic crude. Production from the Syncrude plant (125,000 bbl/d capacity) is expected to begin in 1977, followed by a Shell Canada operation around 1980. The provincial government will participate in the oil sand industry through its joint venture participation in Syncrude and its 50% share in Alberta Energy Company; the latter company participates in related aspects of the Syncrude project, such as pipelines. The result of Alberta's participation in the industry will mean that, directly or indirectly, the province will realize 60% of the total profits. The job creation potential of oil sands projects is estimated to be extensive, with a direct and indirect work force supported by oil sands activities possibly reaching 180,000 persons by the year 2000. Research needs have been identified, particularly in the area of in-situ thermal recovery technology, and the creation of the Alberta Oil Sands Technology and Research Authority has been authorized in order to meet these needs. Although current reserves are sufficient to support 20-30 synthetic crude plants, a number of factors will limit expansion of the industry. 8 figs., 5 tabs.

  8. Geophysical applications for oil sand mine tailings management

    Energy Technology Data Exchange (ETDEWEB)

    Parker, D.; Bauman, P. [WorleyParsons, Calgary, AB (Canada)

    2009-07-01

    Geophysical techniques are applied throughout a mine's life cycle to facilitate siting, constructing and monitoring of tailings dumps and ponds. This presentation described 3 case studies from the Athabasca region in northeast Alberta that demonstrated some of the concerns associated with oil sand mine tailings, and the information that geophysical surveys can provide. The objectives of these studies were to determine the lateral and depth extents of elevated conductivities of soil and groundwater that have high salt concentration from the tailings sand pore fluid. Due to high chloride concentrations within the tailings material, salt within the root zone may affect vegetation. A terrain conductivity survey was designed to map the lateral extents of salinity impact, while an electrical resistivity tomography (ERT) survey was used to delineate the tailings sand leachate at depth. The proper management of oil sand tailings facilities is vital to the life cycle of a mine. It was concluded that geophysical techniques can be instrumental in managing several engineering and environmental challenges, from Pleistocene channel mapping, to tailings pond settling characteristics, to reclaiming tailings sands. 1 ref., 7 figs.

  9. Radiometric Characterization of Sand in Northeast Sinai

    International Nuclear Information System (INIS)

    Ramadan, Kh.A.; Badran, H.M.; Ramadan, Kh.A.; Seddeek, M.K.; Sharshar, T.

    2009-01-01

    Thirty-eight locations covering an area of 350 km 2 in northeast Sinai were investigated by gamma-ray spectroscopy using a 50% HPGe detector. The limits of area are Al-Arish North, El-Hasana South, El-Oga East, and El- Gifgafa West. The range of activity concentrations of 238 U, 234 Th, 226 Ra, 232 Th and 40 K are 0.6-35.2, 3.9-22.6, 4.7-29.6, 4.7-23.9, and 108-295 Bq/kg for sands, respectively. 137 Cs in the region ranged from 0.1-8.0 Bq/kg. No major difference between the studied area and that previously investigated in the costal area in North Sinai. Reliable correlations (R2 = 0.8-0.9) among 238 U, 234 Th, and 226 Ra isotopes was obtained. On the other hand, low correlation (R 2 = 0.6-0.7) was obtained from the analysis of the isotopes of 238 U-seies and 232 Th. No evidence of correlation between the concentrations of radioisotopes and pH contents, TOM, and grain size were found. The soil-plant transfer factor are 226 Ra and 232 Th, 40 K, and 137 Cs, respectively. The wild vegetations collected from the studied area have average concentrations of 1.9, 1.4, 1.3, 254, and 0.3 for 234 Th, 226 Ra, 232 Th, 40 K, and 137 Cs, respectively. The average concentrations of 226 Ra, 232 Th, and 40 K in water samples collected from five wells are 0.02, 0.02, and 1.1 Bq/l, respectively. The average absorbed dose rate for the sand samples were calculated to be 19.4 n Gy h-1. The Raeq activities of the sands are lower than the recommended maximum value of 370 Bq kg-1 criterion limit of Raeq activity for building materials

  10. The influence of groundwater depth on coastal dune development at sand flats close to inlets

    Science.gov (United States)

    Silva, Filipe Galiforni; Wijnberg, Kathelijne M.; de Groot, Alma V.; Hulscher, Suzanne J. M. H.

    2018-05-01

    A cellular automata model is used to analyze the effects of groundwater levels and sediment supply on aeolian dune development occurring on sand flats close to inlets. The model considers, in a schematized and probabilistic way, aeolian transport processes, groundwater influence, vegetation development, and combined effects of waves and tides that can both erode and accrete the sand flat. Next to three idealized cases, a sand flat adjoining the barrier island of Texel, the Netherlands, was chosen as a case study. Elevation data from 18 annual LIDAR surveys was used to characterize sand flat and dune development. Additionally, a field survey was carried out to map the spatial variation in capillary fringe depth across the sand flat. Results show that for high groundwater situations, sediment supply became limited inducing formation of Coppice-like dunes, even though aeolian losses were regularly replenished by marine import during sand flat flooding. Long dune rows developed for high sediment supply scenarios which occurred for deep groundwater levels. Furthermore, a threshold depth appears to exist at which the groundwater level starts to affect dune development on the inlet sand flat. The threshold can vary spatially depending on external conditions such as topography. On sand flats close to inlets, groundwater is capable of introducing spatial variability in dune growth, which is consistent with dune development patterns found on the Texel sand flat.

  11. Ilmenite Mineral's Recovery from Beach Sand Tailings

    International Nuclear Information System (INIS)

    Mulaba-Bafubiandi, Antoine F.; Mukendi-Ngalula, David; Waanders, Frans B.

    2002-01-01

    The mineral ilmenite is the major source of rutile for industrial use and is of interest to paint and fertiliser industries. Enormous unutilised tailing dams lie on the eastern coast of the South Africa. Although covered by a simulation of the original indigenous vegetation, these tailings are still ilmenite bearing and of economic value. Tailings emanating from beach sand mineral slimes dams of the Kwazulu-Natal area (South Africa) have been processed. Screening, flotation, spiral concentration and magnetic separation methods were used either separately or successively. The present work sheds light on alternative routes for the extraction of the ilmenite, from these tailings. It moreover points out the usefulness of the Moessbauer spectroscopy in the mineral processing product monitoring. Tailings from the beach sands were used in the present study after the economic industrial minerals zirconia, ilmenite and rutile had been extracted in previous mining operations. About 61% natural ilmenite recovery was observed in the flotation concentrate of a Humphrey Spiral concentrate while a 62% recovery of hematite was found in the flotation tailings. The combination of screening, spiral concentration and magnetic separation, and flotation yielded a product with the highest ilmenite and hematite concentration being 71% and 19%, respectively. A natural ilmenite mineral, containing 87% ilmenite and 13% hematite, could be produced and extracted from the tailings of the flotation process, collected subsequently to the spiral concentration and the initial screening.

  12. Direct Chlorination of Zircon Sand

    International Nuclear Information System (INIS)

    Dwiretnani Sudjoko; Budi Sulistyo; Pristi Hartati; Sunardjo

    2002-01-01

    It was investigated the direct chlorination of zircon sand in a unit chlorination equipment. The process was in semi batch. The product gas was scrubbed in aqueous NaOH. It was search the influence of time, ratio of reactant and size of particle sand to the concentration of Zr and Si in the product. From these research it was found that as the times, ratio of reactant increased, the concentration of Zr increased, but the concentration of Si decreased, while as grain size of zircon sand decreased the concentration of Zr decreased, but the concentration of Si increased. (author)

  13. Oil sands and the environment

    Energy Technology Data Exchange (ETDEWEB)

    Seeley, R. [Shell Canada Ltd., Calgary, AB (Canada). Calgary Research Centre

    2004-07-01

    Oil sands are a significant resource for Alberta and Canada with continuing growth opportunity. There is a need to ensure sustainable development of the oil sands resources from a social, economic and environmental perspective. The industry has succeeded in terms of proven reserves, technology advancements, reduced operating costs, reliability and market accessibility. Some of the major challenges facing the industry include high capital cost, infrastructure, social services and keeping pace with growth. This presentation outlined the proactive measures that the oil sands industry has taken to manage environmental issues such as sulphur dioxide and nitrogen oxide emissions, greenhouse gases, water management and land reclamation. tabs., figs.

  14. Alberta oil sands royalty regime

    International Nuclear Information System (INIS)

    Asgarpour, S.

    2004-01-01

    The long term objective of the Oil Sands Business Unit of Alberta Energy is to pave the way for Alberta's bitumen production to reach 3 million barrels per day by 2020. This presentation described the national government's role in resource development. It was emphasized that since the Crown is the owner of the oil sands resource, it would benefit by providing strategic leadership and by generating a larger royalty base. The oil sands fiscal regime was described with reference to generic royalty, risk sharing, investment, and project economics. Business rule principles were also outlined along with criteria for project expansions. Both upstream and downstream challenges and opportunities were listed. 4 figs

  15. Kuchler Vegetation

    Data.gov (United States)

    California Natural Resource Agency — Digital version of potential natural plant communites as compiled and published on 'Map of the Natural Vegetation of California' by A. W. Kuchler, 1976. Source map...

  16. Wieslander Vegetation

    Data.gov (United States)

    California Natural Resource Agency — Digital version of the 1945 California Vegetation Type Maps by A. E. Wieslander of the U.S. Forest Service. Source scale of maps are 1:100,000. These compiled maps...

  17. Saltation of non-spherical sand particles.

    Directory of Open Access Journals (Sweden)

    Zhengshi Wang

    Full Text Available Saltation is an important geological process and the primary source of atmospheric mineral dust aerosols. Unfortunately, no studies to date have been able to precisely reproduce the saltation process because of the simplified theoretical models used. For example, sand particles in most of the existing wind sand movement models are considered to be spherical, the effects of the sand shape on the structure of the wind sand flow are rarely studied, and the effect of mid-air collision is usually neglected. In fact, sand grains are rarely round in natural environments. In this paper, we first analyzed the drag coefficients, drag forces, and starting friction wind speeds of sand grains with different shapes in the saltation process, then established a sand saltation model that considers the coupling effect between wind and the sand grains, the effect of the mid-air collision of sand grains, and the effect of the sand grain shape. Based on this model, the saltation process and sand transport rate of non-spherical sand particles were simulated. The results show that the sand shape has a significant impact on the saltation process; for the same wind speed, the sand transport rates varied for different shapes of sand grains by as much as several-fold. Therefore, sand shape is one of the important factors affecting wind-sand movement.

  18. Gold and other metals in big sagebrush (Artemisia tridentata Nutt.) as an exploration tool, Gold Run District, Humboldt County, Nevada

    Science.gov (United States)

    Erdman, J.A.; Cookro, T.M.; O'Leary, R. M.; Harms, T.F.

    1988-01-01

    Big sagebrush - a cold-desert species that dominates the terrain over large parts of western United States - was sampled along several traverses that crossed thermally metamorphosed limestone, phyllitic shale, and schist of the Middle and Upper Cambrian Preble Formation that host skarn-, disseminated gold and silver-, and hot springs gold-type mineral occurrences. Patterns of detectable levels of gold (8 to 28 ppb or ng g-1) in ash of new growth were consistent with areas affected by known or suspected gold mineralization. Soils collected along one of the traverses where a selenium-indicator plant was common contained no gold above background levels of 2ppb, but were consistently high in As, Sb, and Zn, and several samples were unusually high in Se (maximum 11 ppm or ??g g-1). Sagebrush along this traverse contained Li at levels above norms for this species. We also found a puzzling geochemical anomaly at a site basinward from active hot springs along a range-front fault scarp. Sagebrush at this site contained a trace of gold and an unusually high concentration of Cd (13 ppm) and the soil had anomalous concentrations of Cd and Bi (3.2 and 6 ppm, respectively). The source of this anomaly could be either metal-rich waters from an irrigation ditch or leakage along a buried fault. Despite the limited nature of the study, we conclude that gold in sagebrush could be a cost-effective guide to drilling locations in areas where the geology seems favorable for disseminated and vein precious metals. ?? 1988.

  19. Reclaimability of the spent sand mixture – sand with bentonite – sand with furfuryl resin

    Directory of Open Access Journals (Sweden)

    J. Dańko

    2011-04-01

    Full Text Available Introduction of new binding materials and new technologies of their hardening in casting moulds and cores production requires theapplication of reclamation methods adequate to their properties as well as special devices realizing tasks. The spent sands circulationsystem containing the same kind of moulding and core sands is optimal from the point of view of the expected reclamation results.However, in the face of a significant variability of applied technologies and related to them various reclamation methods, the need - of theobtained reclamation products assessment on the grounds of systematic criteria and uniform bases – arises, with a tendency of indicatingwhich criteria are the most important for the given sand system. The reclaimability results of the mixture of the spent moulding sand withGeko S bentonite and the spent core sand with the Kaltharz 404U resin hardened by acidic hardener 100 T3, are presented in the paper.Investigations were performed with regard to the estimation of an influence of core sands additions (10 –25% on the reclaimed materialquality. Dusts and clay content in the reclaim, its chemical reaction (pH and ignition loss were estimated. The verification of the reclaiminstrumental assessment was performed on the basis of the technological properties estimation of moulding sand with bentonite, where the reclaimed material was used as a matrix.

  20. Namibia : triaxial test on sand

    DEFF Research Database (Denmark)

    Steenfelt, Jørgen S.; Jacobsen, Kim P.

    In connection with a harbour project the friction angle of a fine sand is required. On Friday 13 March 1998 the Danish Geotechnical Institute (DGI) delivered app. 2.5 kg sand for testing at the Geotechnical Engineering Laboratory, Aalborg University. The present Data Report summarises the results...... of two CID, isotropically consolidated, drained triaxial tests carried out according to the instructions in DG1 letter dated 13 March 1998....

  1. Technology unlocks tar sands energy

    Energy Technology Data Exchange (ETDEWEB)

    Law, C

    1967-09-25

    Tar sand processing technology has been developed primarily in the categories of extraction techniques and in-situ processing. In October, a $235 million venture into tar sand processing will be inspected by visitors from many points on the globe. A synthetic crude of premium quality will be flowing through a 16-in. pipeline from the Tar Island plant site of Great Canadian Oil Sands to Edmonton. This processing plant uses an extractive mining technique. The tar sand pay zone in this area averages approximately 150 ft in thickness with a 50-ft overburden. It has been estimated that the tar sands cannot be exploited when the formation thickness is less than 100 ft and overburden exceeds the same amount. This indicates that extraction techniques can only be used to recover approximately 15% of the tar sand deposits. An in-situ recovery technique developed by Shell of Canada is discussed in detail. In essence it is selective hydraulic fracturing, followed by the injection of emulsifying chemicals and steam.

  2. Analysis of the environmental control technology for tar sand development

    Energy Technology Data Exchange (ETDEWEB)

    de Nevers, N.; Glenne, B.; Bryner, C.

    1979-06-01

    The environmental technology for control of air pollution, water pollution, and for the disposal, stabilization, and vegetation of the waste tar sand were thoroughly investigated. Although some difficulties may be encountered in any of these undertakings, it seems clear that the air and water pollution problems can be solved to meet any applicable standard. Currently there are two large-scale plants producing liquid fuels from tar sands in Alberta, Canada which use similar technology involving surface mining, hot water extraction, and surface disposal of waste sand. These projects all meet the Canadian environmental control regulations in force at the time they began. The largest US deposits of tar sands are much smaller than the Canadian; 95 percent are located in the state of Utah. Their economics do not appear as attractive as the Canadian deposits. The environmental control costs are not large enough to make an otherwise economic project uneconomic. The most serious environmental conflict likely to occur over the recovery of liquid fuels from the US deposits of tar sands is that caused by the proximity of the deposits to national parks, national monuments, and a national recreation area in Utah. These areas have very stringent air pollution requirements; and even if the air pollution control requirements can be met, there may still be adequate opposition to large-scale mining ventures in these areas to prevent their commercial exploitation. Another environmental constraint may be water rights availability.Essentially all of the water running in the Colorado river basin is now legally allocated. Barring new interpretations of the legality of water rights purchase, Utah tar sands developments should be able to obtain water by purchasing existing irrigation water rights.

  3. Using resistance and resilience concepts to reduce impacts of invasive annual grasses and altered fire regimes on the sagebrush ecosystem and greater sage-grouse: A strategic multi-scale approach

    Science.gov (United States)

    Jeanne C. Chambers; David A. Pyke; Jeremy D. Maestas; Mike Pellant; Chad S. Boyd; Steven B. Campbell; Shawn Espinosa; Douglas W. Havlina; Kenneth E. Mayer; Amarina Wuenschel

    2014-01-01

    This Report provides a strategic approach for conservation of sagebrush ecosystems and Greater Sage- Grouse (sage-grouse) that focuses specifically on habitat threats caused by invasive annual grasses and altered fire regimes. It uses information on factors that influence (1) sagebrush ecosystem resilience to disturbance and resistance to invasive annual grasses and (2...

  4. Science framework for conservation and restoration of the sagebrush biome: Linking the Department of the Interior’s Integrated Rangeland Fire Management Strategy to long-term strategic conservation actions

    Science.gov (United States)

    J.C. Chambers; J.L. Beck; J.B. Bradford; J. Bybee; S. Campbell; J. Carlson; T.J. Christiansen; K.J. Clause; G. Collins; M.R. Crist; J.B. Dinkins; K.E. Doherty; F. Edwards; S. Espinosa; K.A. Griffin; P. Griffin; J.R. Haas; S.E. Hanser; D.W. Havlina; K.F. Henke; J.D. Hennig; L.A. Joyce; F.M. Kilkenny; S.M. Kulpa; L.L. Kurth; J.D. Maestas; M. Manning; K.E. Mayer; B.A. Mealor; C. McCarthy; M. Pellant; M.A. Perea; K.L. Prentice; D.A. Pyke; L.A. Wiechman; A. Wuenschel

    2017-01-01

    The Science Framework is intended to link the Department of the Interior’s Integrated Rangeland Fire Management Strategy with long-term strategic conservation actions in the sagebrush biome. The Science Framework provides a multiscale approach for prioritizing areas for management and determining effective management strategies within the sagebrush biome. The emphasis...

  5. Using resilience and resistance concepts to manage threats to sagebrush ecosystems, Gunnison sage-grouse, and Greater sage-grouse in their eastern range: A strategic multi-scale approach

    Science.gov (United States)

    Jeanne C. Chambers; Jeffrey L. Beck; Steve Campbell; John Carlson; Thomas J. Christiansen; Karen J. Clause; Jonathan B. Dinkins; Kevin E. Doherty; Kathleen A. Griffin; Douglas W. Havlina; Kenneth F. Henke; Jacob D. Hennig; Laurie L. Kurth; Jeremy D. Maestas; Mary Manning; Kenneth E. Mayer; Brian A. Mealor; Clinton McCarthy; Marco A. Perea; David A. Pyke

    2016-01-01

    This report provides a strategic approach developed by a Western Association of Fish and Wildlife Agencies interagency working group for conservation of sagebrush ecosystems, Greater sage-grouse, and Gunnison sage-grouse. It uses information on (1) factors that influence sagebrush ecosystem resilience to disturbance and resistance to nonnative invasive annual grasses...

  6. Experimental Measurement of Diffusive Extinction Depth and Soil Moisture Gradients in Southwestern Saudi Arabian Dune Sand

    KAUST Repository

    Mughal, Iqra

    2013-05-01

    In arid lands, a major contribution to water loss is by soil water evaporation. Desert sand dunes in arid regions are devoid of runoff and have high rates of infiltration. Rainwater is commonly stored within them because of the low permeability soils in the underlying desert pavement. In such cases, moisture is confined in the sand dune below a depth, termed as the “extinction depth”, where it is protected from evaporation during long dry periods. Moreover, desert sand dunes have sparse vegetation, which results in low transpiration losses from the stored water. The water accumulated below the extinction depth of the sand dunes can be utilized for various purposes such as in irrigation to support desert agriculture. In this study, field experiments were conducted in Western Saudi Arabia to monitor the soil moisture gradients and determine the diffusive extinction depth of dune sand. The dune sand was saturated with water and was exposed to natural conditions (evaporation and precipitation). The decline of the water level in the sand column was continuously recorded using transducers and sensors installed at different depths monitored the temporal variation of temperature and moisture content within the sand. The hydrological simulator HYDRUS-1D was used to construct the vertical profiles of soil water content and temperature and the results obtained from HYDRUS-1D were compared to the gradients monitored by the sensors.

  7. VEGETATION MAPPING IN WETLANDS

    Directory of Open Access Journals (Sweden)

    F. PEDROTTI

    2004-01-01

    Full Text Available The current work examines the main aspects of wetland vegetation mapping, which can be summarized as analysis of the ecological-vegetational (ecotone gradients; vegetation complexes; relationships between vegetation distribution and geomorphology; vegetation of the hydrographic basin lo which the wetland in question belongs; vegetation monitoring with help of four vegetation maps: phytosociological map of the real and potential vegetation, map of vegetation dynamical tendencies, map of vegetation series.

  8. Enhancing Pre- and Post-Wildfire Vegetation Recovery and Understanding Feedbacks of Cheatgrass invasion Using NASA Earth Observations

    Science.gov (United States)

    Olsen, N.; Counts, A.; Quistorff, C.; Ohr, C. A.; Toner, C.

    2017-12-01

    Increasing wildfire frequency and severity has emphasized the importance of post-wildfire recovery efforts in southern Idaho's sagebrush ecosystems. These changing fire regimes favor invasive grass species while hindering native sagebrush habitat regeneration, causing a positive feedback cycle of invasive growth - wildfires - invasive growth. Due to this undesirable process and anthropogenic influences, the sagebrush ecosystem is one of the most endangered in the US. In this project the NASA DEVELOP group of Pocatello, Idaho partnered with the Bureau of Land Management, Idaho Department of Fish and Game, and the US Department of Agriculture to characterize ecosystem recovery following the Crystal (2006), Henry Creek (2016), Jefferson (2010), and Soda (2015) wildfires. Determining vegetation cover heterogeneity and density can be time consuming and the factors affecting ecosystem recovery can be complex. In addition, restoration success is difficult to determine as vegetation composition is not often known prior to wildfire events and monitoring vegetation composition after restoration efforts can be resource intensive. These wildfires temporal monitoring consisted of 2001 to 2017 using NASA Earth observations such as Landsat 5 Thermal Mapper (TM), Landsat 8 Operational Land Imager (OLI), Terra Moderate Resolution Imaging Spectroradiometer (MODIS), and Shuttle Radar Topography Mission (SRTM) to determine the most significant factors of wildfire recovery and the influence targeted grazing could have for recovery. In addition, this project will include monitoring of invasive species propagation and whether spatial patterns or extents of the wildfire contribute to propagation. Understanding the key variables that made reseeding and natural recovery work in some areas, assessing why they failed in others, and identifying factors that made non-native propagation ideal are important issues for land managers in this region.

  9. Oil sands tailings management project

    Energy Technology Data Exchange (ETDEWEB)

    Godwalt, C. [Alberta WaterSMART, Calgary, AB (Canada); Kotecha, P. [Suncor Energy Inc, Calgary, AB (Canada); Aumann, C. [Alberta Innovates - Technology Futures, Alberta Governement, AB (Canada)

    2010-11-15

    The Oil sands leadership initiative (OSLI) works with the Government of Alberta on the development of the oil sands industry, considering environmental, economical and social aspects. Water management was identified as one of most important areas to focus on. Alberta WaterSMART was requested to support the development and the management of projects resulting from the work done or underway in this field. The development of a regional water management solution stood out as the most interesting solution to obtain significant results. In the Athabasca Region, oil sands producers work independently on their water sourcing and disposal with particular attention to fresh water conservation and economics. The Athabasca River represents a source for mines and distant saline aquifers are the target of steam assisted gravity drainage (SAGD) operators. As part of a four-phase project aiming to study the environmental and economic footprint (EEF) benefit of alternatives for Athabasca oil sands production water supply and disposal, the purpose of the tailings water management project was to identify tailings treatment technologies that are ready to be implemented, and to design and evaluate solutions in order to improve regional oil sands production water sourcing and disposal. Alternatives were evaluated based on their total EEF, applying a lifecycle assessment methodology with a particular attention on the quantification of important performance indicators. 25 refs., 8 tabs., 40 figs.

  10. Oil sands tailings management project

    International Nuclear Information System (INIS)

    Godwalt, C.; Kotecha, P.; Aumann, C.

    2010-11-01

    The Oil sands leadership initiative (OSLI) works with the Government of Alberta on the development of the oil sands industry, considering environmental, economical and social aspects. Water management was identified as one of most important areas to focus on. Alberta WaterSMART was requested to support the development and the management of projects resulting from the work done or underway in this field. The development of a regional water management solution stood out as the most interesting solution to obtain significant results. In the Athabasca Region, oil sands producers work independently on their water sourcing and disposal with particular attention to fresh water conservation and economics. The Athabasca River represents a source for mines and distant saline aquifers are the target of steam assisted gravity drainage (SAGD) operators. As part of a four-phase project aiming to study the environmental and economic footprint (EEF) benefit of alternatives for Athabasca oil sands production water supply and disposal, the purpose of the tailings water management project was to identify tailings treatment technologies that are ready to be implemented, and to design and evaluate solutions in order to improve regional oil sands production water sourcing and disposal. Alternatives were evaluated based on their total EEF, applying a lifecycle assessment methodology with a particular attention on the quantification of important performance indicators. 25 refs., 8 tabs., 40 figs.

  11. Vegetative regeneration

    Science.gov (United States)

    George A. Schier; John R. Jones; Robert P. Winokur

    1985-01-01

    Aspen is noted for its ability to regenerate vegetatively by adventitious shoots or suckers that arise on its long lateral roots. It also produces sprouts from stumps and root collars; but they are not common. In a survey of regeneration after clearcutting mature aspen in Utah. Baker (1918b) found that 92% of the shoots originated from roots, 7% from root collars, and...

  12. Understory vegetation

    Science.gov (United States)

    Steve Sutherland; Todd F. Hutchinson; Jennifer L. Windus

    2003-01-01

    This chapter documents patterns of species composition and diversity within the understory vegetation layer and provides a species list for the four study areas in southern Ohio. Within each of 108 plots, we recorded the frequency of all vascular plant species in sixteen 2-m² quadrats. We recorded 297 species, including 187 forbs (176 perennials, 9 annuals, 2...

  13. 75 FR 6364 - Process for Requesting a Variance From Vegetation Standards for Levees and Floodwalls

    Science.gov (United States)

    2010-02-09

    ..., channels, or shore- line or river-bank protection systems such as revetments, sand dunes, and barrier...) toe (subject to preexisting right-of-way). f. The vegetation variance process is not a mechanism to...

  14. Sands at Gusev Crater, Mars

    Science.gov (United States)

    Cabrol, Nathalie A.; Herkenhoff, Kenneth E.; Knoll, Andrew H.; Farmer, Jack D.; Arvidson, Raymond E.; Grin, E.A.; Li, Ron; Fenton, Lori; Cohen, B.; Bell, J.F.; Yingst, R. Aileen

    2014-01-01

    Processes, environments, and the energy associated with the transport and deposition of sand at Gusev Crater are characterized at the microscopic scale through the comparison of statistical moments for particle size and shape distributions. Bivariate and factor analyses define distinct textural groups at 51 sites along the traverse completed by the Spirit rover as it crossed the plains and went into the Columbia Hills. Fine-to-medium sand is ubiquitous in ripples and wind drifts. Most distributions show excess fine material, consistent with a predominance of wind erosion over the last 3.8 billion years. Negative skewness at West Valley is explained by the removal of fine sand during active erosion, or alternatively, by excess accumulation of coarse sand from a local source. The coarse to very coarse sand particles of ripple armors in the basaltic plains have a unique combination of size and shape. Their distribution display significant changes in their statistical moments within the ~400 m that separate the Columbia Memorial Station from Bonneville Crater. Results are consistent with aeolian and/or impact deposition, while the elongated and rounded shape of the grains forming the ripples, as well as their direction of origin, could point to Ma'adim Vallis as a possible source. For smaller particles on the traverse, our findings confirm that aeolian processes have dominated over impact and other processes to produce sands with the observed size and shape patterns across a spectrum of geologic (e.g., ripples and plains soils) and aerographic settings (e.g., wind shadows).

  15. Restoring sand shinnery oak prairies with herbicide and grazing in New Mexico

    Science.gov (United States)

    Zavaleta, Jennifer C.; Haukos, David A.; Grisham, Blake A.; Boal, Clint W.; Dixon, Charles

    2016-01-01

    Sand shinnery oak (Quercus havardii) prairies are increasingly disappearing and increasingly degraded in the Southern High Plains of Texas and New Mexico. Restoring and managing sand shinnery oak prairie can support biodiversity, specific species of conservation concern, and livestock production. We measured vegetation response to four treatment combinations of herbicide (tebuthiuron applied at 0.60 kg/ha) and moderate-intensity grazing (50% removal of annual herbaceous production) over a 10-year period in a sand shinnery oak prairie of eastern New Mexico. We compared the annual vegetation response to the historical climax plant community (HCPC) as outlined by the U.S. Department of Agriculture Ecological Site Description. From 2 to 10 years postapplication, tebuthiuron-treated plots had reduced shrub cover with twice as much forb and grass cover as untreated plots. Tebuthiuron-treated plots, regardless of the presence of grazing, most frequently met HCPC. Tebuthiuron and moderate-intensity grazing increased vegetation heterogeneity and, based on comparison of the HCPC, successfully restored sand shinnery oak prairie to a vegetation composition similar to presettlement.

  16. Spontaneous revegetation vs. forestry reclamation in post-mining sand pits

    Czech Academy of Sciences Publication Activity Database

    Šebelíková, L.; Řehounková, Klára; Prach, Karel

    2016-01-01

    Roč. 23, č. 14 (2016), s. 13598-13605 ISSN 0944-1344 R&D Projects: GA ČR(CZ) GAP505/11/0256 Institutional support: RVO:67985939 Keywords : sand pits * vegetation * restoration Subject RIV: EH - Ecology, Behaviour Impact factor: 2.741, year: 2016

  17. Vegetation Response to Western Juniper Slash Treatments

    Science.gov (United States)

    O'Connor, Casey; Miller, Rick; Bates, Jonathan D.

    2013-09-01

    The expansion of piñon-juniper woodlands the past 100 years in the western United States has resulted in large scale efforts to kill trees and recover sagebrush steppe rangelands. It is important to evaluate vegetation recovery following woodland control to develop best management practices. In this study, we compared two fuel reduction treatments and a cut-and-leave (CUT) treatment used to control western juniper ( Juniperus occidentalis spp. occidentalis Hook.) of the northwestern United States. Treatments were; CUT, cut-and-broadcast burn (BURN), and cut-pile-and-burn the pile (PILE). A randomized complete block design was used with five replicates of each treatment located in a curl leaf mahogany ( Cercocarpus ledifolius Nutt. ex Torr. & A. Gray)/mountain big sagebrush ( Artemisia tridentata Nutt. spp. vaseyana (Rydb.) Beetle)/Idaho fescue ( Festuca idahoensis Elmer) association. In 2010, 4 years after tree control the cover of perennial grasses (PG) [Sandberg's bluegrass ( Poa secunda J. Pres) and large bunchgrasses] were about 4 and 5 % less, respectively, in the BURN (7.1 ± 0.6 %) than the PILE (11.4 ± 2.3 %) and CUT (12.4 ± 1.7 %) treatments ( P < 0.0015). In 2010, cover of invasive cheatgrass ( Bromus tectorum L.) was greater in the BURN (6.3 ± 1.0 %) and was 50 and 100 % greater than PILE and CUT treatments, respectively. However, the increase in perennial bunchgrass density and cover, despite cheatgrass in the BURN treatment, mean it unlikely that cheatgrass will persist as a major understory component. In the CUT treatment mahogany cover increased 12.5 % and density increased in from 172 ± 25 to 404 ± 123 trees/ha. Burning, killed most or all of the adult mahogany, and mahogany recovery consisted of 100 and 67 % seedlings in the PILE and BURN treatments, respectively. After treatment, juniper presence from untreated small trees (<1 m tall; PILE and CUT treatments) and seedling emergence (all treatments) represented 25-33 % of pre-treatment tree

  18. componente vegetal

    Directory of Open Access Journals (Sweden)

    Fabio Moscovich

    2005-01-01

    Full Text Available In order to determine environmental impact, indicators based on vegetation characteristics that would generate the forestry monoculture with the adjacent native forest, 32 sample unit were installed in an area of LIPSIA private enterprise, Esperanza Department, Misiones with those characteristics. The plots of 100 m2 were distributed systematically every 25 meters. The vegetation was divided in stratum: superior (DBH ≥ 10 cm, middle (1,6 cm ≤ DBH > 10 cm and inferior (DBH< cm. There were installed 10 plots in a logged native forest, 10 plots in a 18 years old Pinus elliottii Engelm. with approximately 400 trees/ha., 6 plots in a 10 – 25 years old Araucaria angustifolia (Bertd. Kuntze limiting area with approximately 900 trees/ha., and 6 plots located in this plantation. In the studied area were identified 150 vegetation species. In the inferior stratum there were found differences as function of various floristic diversity indexes. In all the cases the native forest showed larger diversity than plantations, followed by Pinus elliottii, Araucaria plantation and Araucaria limiting area. All the studied forest fitted to a logarithmical series of species distributions, that would indicate the incidence of a environmental factor in this distribution.

  19. Vegetated dune morphodynamics during recent stabilization of the Mu Us dune field, north-central China

    Science.gov (United States)

    Xu, Zhiwei; Mason, Joseph A.; Lu, Huayu

    2015-01-01

    The response of dune fields to changing environmental conditions can be better understood by investigating how changing vegetation cover affects dune morphodynamics. Significant increases in vegetation and widespread dune stabilization over the years 2000-2012 are evident in high-resolution satellite imagery of the Mu Us dune field in north-central China, possibly a lagged response to changing wind strength and temperature since the 1970s. These trends provide an opportunity to study how dune morphology changes with increasing vegetation stabilization. Vegetation expansion occurs mainly by expansion of pre-existing patches in interdunes. As vegetation spreads from interdunes onto surrounding dunes, it modifies their shapes in competition with wind-driven sand movement, primarily in three ways: 1) vegetation anchoring horns of barchans transforms them to parabolic dunes; 2) vegetation colonizes stoss faces of barchan and transverse dunes, resulting in lower dune height and an elongated stoss face, with shortening of barchan horns; and 3) on transverse dunes, the lee face is fixed by plants that survive sand burial. Along each of these pathways of stabilization, dune morphology tends to change from more barchanoid to more parabolic forms, but that transformation is not always completed before full stabilization. Artificial stabilization leads to an extreme case of "frozen" barchans or transverse dunes with original shapes preserved by rapid establishment of vegetation. Observations in the Mu Us dune field emphasize the point that vegetation growth and aeolian sand transport not only respond to external factors such as climate but also interact with each other. For example, some barchans lose sand mass during vegetation fixation, and actually migrate faster as they become smaller, and vegetation growth on a barchan's lower stoss face may alter sand transport over the dune in a way that favors more rapid stabilization. Conceptual models were generalized for the

  20. Modelling offshore sand wave evolution

    NARCIS (Netherlands)

    Nemeth, Attila; Hulscher, Suzanne J.M.H.; van Damme, Rudolf M.J.

    2007-01-01

    We present a two-dimensional vertical (2DV) flow and morphological numerical model describing the behaviour of offshore sand waves. The model contains the 2DV shallow water equations, with a free water surface and a general bed load formula. The water movement is coupled to the sediment transport

  1. Rheology of oil sands slurries

    Energy Technology Data Exchange (ETDEWEB)

    Chow, R.; Zhou, J. [Alberta Research Council, Edmonton, AB (Canada). Mineral Oil Sands Unit; Wallace, D. [Dean Wallace Consulting Inc., Beaumont, AB (Canada)

    2006-07-01

    This study focused on integrating rheology and colloid science to improve recovery of bitumen in surface mined oil sands. Factors that influence recovery, such as conditions of particle interaction, solids concentration and shear rate, were reviewed. In an effort to understand the rheological behaviour of clay-in-water suspensions, an elaborate procedure was developed to separate an inter-bedded clay layer from a site at Albian Sands Energy Inc. The variables were water chemistry, solids concentration, and shear rate. The research study was conducted at the Alberta Research Council with the support of the CONRAD Extraction Group. A controlled stress rheometer was used to provide the quantitative evaluations of the clay slurry properties. The research results indicate that the viscoelastic properties of the slurry are highly influenced by the shear history of the slurry, solids content, calcium concentration, and sample aging. Shear thinning behaviour was observed in all slurry samples, but the slurry viscosity increased with test time for a given shear rate. In order to classify the slurries, a method was developed to distinguish the gel strength. The slurries were then classified into 3 distinct patterns, including no gel, weak gel and strong gel. The evolution of the experimental protocols were described along with the current stability maps that correlate the domains of the gel strength according to the solids concentration, calcium ion content, and shear rate. It was concluded that the rheological properties of oil sands slurries influence bitumen recovery in commercial surface-mined oil sands operations. tabs., figs.

  2. Geology on a Sand Budget

    Science.gov (United States)

    Kane, Jacqueline

    2004-01-01

    Earth science teachers know how frustrating it can be to spend hundreds of dollars on three-dimensional (3-D) models of Earth's geologic features, to use the models for only a few class periods. To avoid emptying an already limited science budget, the author states that teachers can use a simple alternative to the expensive 3-D models--sand. She…

  3. Intermittent fasting modulation of the diabetic syndrome in sand rats. II. In vivo investigations.

    Science.gov (United States)

    Belkacemi, Louiza; Selselet-Attou, Ghalem; Louchami, Karim; Sener, Abdullah; Malaisse, Willy J

    2010-11-01

    This study deals with the effects of daily intermittent fasting for 15 h upon the development of diabetes in sand rats exposed to a hypercaloric diet. The same pattern of daily intermittent fasting was imposed on sand rats maintained on a purely vegetal diet (control animals). Over the last 30 days of the present experiments, non-fasting animals gained weight, whilst intermittently fasting sand rats lost weight. In this respect, there was no significant difference between control animals and either diabetic or non-diabetic sand rats exposed to the hypercaloric diet. The postprandial glycemia remained fairly stable in the control animals. During a 3-week transition period from a purely vegetal to a hypercaloric diet, the post-prandial glycemia increased by 5.95 ± 1.26 mM (n=6) in diabetic sand rats, as distinct from an increase of only 0.45 ± 0.56 mM (n=6) in the non-diabetic animals. During the intermittent fasting period, the postprandial glycemia decreased significantly in the diabetic animals, but not so in the non-diabetic sand rats. Before the switch in food intake, the peak glycemia at the 30th min of an intraperitoneal glucose tolerance test was already higher in the diabetic than non-diabetic rats. In both the non-diabetic and diabetic sand rats, intermittent fasting prevented the progressive deterioration of glucose tolerance otherwise observed in non-fasting animals. These findings reveal that, at least in sand rats, intermittent daily fasting prevents the progressive deterioration of glucose tolerance otherwise taking place when these animals are exposed to a hypercaloric diet.

  4. Tidal dynamics in the sand motor lagoon

    NARCIS (Netherlands)

    De Vries, S.; Radermacher, M.; De Schipper, M.A.; Stive, M.J.F.

    2015-01-01

    The Sand Motor is a mega-nourishment characterized by a very large sand volume of around 20 million m3 placed along the Dutch coast. The Sand Motor is a pilot project to evaluate the performance of an alternative nourishment strategy with respect to different functions of the coastal system. Within

  5. UAV-imaging to model growth response of marram grass to sand burial: Implications for coastal dune development

    Science.gov (United States)

    Nolet, Corjan; van Puijenbroek, Marinka; Suomalainen, Juha; Limpens, Juul; Riksen, Michel

    2018-04-01

    Vegetated coastal dunes have the capacity to keep up with sea-level rise by accumulating and stabilizing wind-blown sand. In Europe, this is attributed to marram grass (Ammophila arenaria), a coastal grass species that combines two unique advantages for dune-building: (1) a very high tolerance to burial by wind-blown sand, and (2) more vigorous growth due to positive feedback to sand burial. However, while these vegetation characteristics have been demonstrated, observational data has not been used to model a function to describe the growth response of Ammophila to sand burial. Studies that model coastal dune development by incorporating positive feedback, as a result, may be hampered by growth functions that are unvalidated against field data. Therefore, this study aims to parameterize an empirical relationship to model the growth response of Ammophila to burial by wind-blown sand. A coastal foredune along a nourished beach in the Netherlands was monitored from April 2015 to April 2016. High-resolution geospatial data was acquired using an Unmanned Aerial Vehicle (UAV). Growth response of Ammophila, expressed by changes in Normalized Difference Vegetation Index (Δ NDVI) and vegetation cover (Δ Cover), is related to a sand burial gradient by fitting a Gaussian function using nonlinear quantile regression. The regression curves indicate an optimal burial rate for Ammophila of 0.31 m of sand per growing season, and suggest (by extrapolation of the data) a maximum burial tolerance for Ammophila between 0.78 (for Δ Cover) and 0.96 m (for Δ NDVI) of sand per growing season. These findings are advantageous to coastal management: maximizing the potential of Ammophila to develop dunes maximizes the potential of coastal dunes to provide coastal safety.

  6. Aeolian nutrient fluxes following wildfire in sagebrush steppe: implications for soil carbon storage

    Directory of Open Access Journals (Sweden)

    N. J. Hasselquist

    2011-12-01

    Full Text Available Pulses of aeolian transport following fire can profoundly affect the biogeochemical cycling of nutrients in semi-arid and arid ecosystems. Our objective was to determine horizontal nutrient fluxes occurring in the saltation zone during an episodic pulse of aeolian transport that occurred following a wildfire in a semi-arid sagebrush steppe ecosystem in southern Idaho, USA. We also examined how temporal trends in nutrient fluxes were affected by changes in particle sizes of eroded mass as well as nutrient concentrations associated with different particle size classes. In the burned area, total carbon (C and nitrogen (N fluxes were as high as 235 g C m−1 d−1 and 19 g N m−1 d−1 during the first few months following fire, whereas C and N fluxes were negligible in an adjacent unburned area throughout the study. Temporal variation in C and N fluxes following fire was largely attributable to the redistribution of saltation-sized particles. Total N and organic C concentrations in the soil surface were significantly lower in the burned relative to the unburned area one year after fire. Our results show how an episodic pulse of aeolian transport following fire can affect the spatial distribution of soil C and N, which, in turn, can have important implications for soil C storage. These findings demonstrate how an ecological disturbance can exacerbate a geomorphic process and highlight the need for further research to better understand the role aeolian transport plays in the biogeochemical cycling of C and N in recently burned landscapes.

  7. Weak interspecific interactions in a sagebrush steppe? Conflicting evidence from observations and experiments.

    Science.gov (United States)

    Adler, Peter B; Kleinhesselink, Andrew; Giles, Hooker; Taylor, J Bret; Teller, Brittany; Ellner, Stephen P

    2018-04-28

    Stable coexistence requires intraspecific limitations to be stronger than interspecific limitations. The greater the difference between intra- and interspecific limitations, the more stable the coexistence, and the weaker the competitive release any species should experience following removal of competitors. We conducted a removal experiment to test whether a previously estimated model, showing surprisingly weak interspecific competition for four dominant species in a sagebrush steppe, accurately predicts competitive release. Our treatments were 1) removal of all perennial grasses and 2) removal of the dominant shrub, Artemisia tripartita. We regressed survival, growth and recruitment on the locations, sizes, and species identities of neighboring plants, along with an indicator variable for removal treatment. If our "baseline" regression model, which accounts for local plant-plant interactions, accurately explains the observed responses to removals, then the removal coefficient should be non-significant. For survival, the removal coefficients were never significantly different from zero, and only A. tripartita showed a (negative) response to removals at the recruitment stage. For growth, the removal treatment effect was significant and positive for two species, Poa secunda and Pseudoroegneria spicata, indicating that the baseline model underestimated interspecific competition. For all three grass species, population models based on the vital rate regressions that included removal effects projected 1.4 to 3-fold increases in equilibrium population size relative to the baseline model (no removal effects). However, we found no evidence of higher response to removal in quadrats with higher pretreatment cover of A. tripartita, or by plants experiencing higher pre-treatment crowding by A. tripartita, raising questions about the mechanisms driving the positive response to removal. While our results show the value of combining observations with a simple removal experiment

  8. The Karakum and Kyzylkum sand seas dynamics; mapping and palaeoclimatic interpretations

    Science.gov (United States)

    Maman, Shimrit; Blumberg, Dan G.; Tsoar, Haim; Porat, Naomi

    2015-04-01

    Sand seas are large basins in deserts that are mantled by wind-swept sand and that exhibit varying degrees of vegetation cover. Wilson (1973) was the first to globally map and classify sand seas. Beyond Wilson's maps, however, little research has been published regarding the Karakum and Kyzylkum sand seas of Central Asia. Wilson's maps delineate active ergs from inactive ergs based solely on precipitation. His assumption of annual average rainfall as a factor determining mobility vs. stability of sand seas is too simplistic and does not take into consideration other factors such as biogenic soil crusts and wind power, both of which are known to have major effects on the dynamics of sand dunes. Literature related to mapping and classifying the Central Asian ergs by remote sensing or sand sea classification state (stable/active) is lacking. Moreover, the palaeoclimatic significance of dunes in Central Asia is difficult to assess, as there has been few studies of dune stratigraphy and numerical ages are lacking. Optically stimulated luminescence (OSL) is a firm optical dating method that is used to determine the elapsed time since quartz grains were last exposed to sunlight, thus, their burial. Yet, absolute ages indicating mobilization and stabilization of these sands, are still inadequately known and are here under discussion. The broad concern of this research was to determine the dynamics of the Central Asian sand seas and study the palaeoclimatic changes that brought to their stabilization. As there are no reliable maps or aeolian discussion of these sands, establishment of a digital data base was initially conducted, focusing on identifying and mapping these sand seas. The vast area and inaccessibility make traditional mapping methods virtually impossible. A variety of space-borne imagery both optical and radar, with varying spectral and spatial resolutions was used. These images provided the basis for mapping sand distribution, dune forms, and vegetation cover

  9. METHOD OF PROCESSING MONAZITE SAND

    Science.gov (United States)

    Welt, M.A.; Smutz, M.

    1958-08-26

    A process is described for recovering thorium, uranium, and rare earth values from monazite sand. The monazite sand is first digested with sulfuric acid and the resulting "monazite sulfate" solution is adjusted to a pH of between 0.4 and 3.0, and oxalate anions are added causing precipitation of the thorium and the rare earths as the oxalates. The oxalate precipitate is separated from the uranium containing supernatant solution, and is dried and calcined to the oxides. The thorium and rare earth oxides are then dissolved in nitric acid and the solution is contacted with tribntyl phosphate whereby an organic extract phase containing the cerium and thorium values is obtained, together with an aqueous raffinate containing the other rare earth values. The organic phase is then separated from the aqueous raffinate and the cerium and thorium are back extracted with an aqueous medium.

  10. Natural and human controls of the Holocene evolution of the beach, aeolian sand and dunes of Caesarea (Israel)

    Science.gov (United States)

    Roskin, J.; Sivan, D.; Shtienberg, G.; Roskin, E.; Porat, N.; Bookman, R.

    2015-12-01

    The study focuses on the Holocene appearance, chronology and drivers of beach sand deposition and inland aeolian sand transport around the Roman-Byzantine ruins of Caesarea, Israel. Beach sand, sand sheets, nebkha, linear and transverse dunes as well as parabolic and transverse interdunes along two transects were sampled in the current study down to their substrate. Sixteen new optically stimulated luminescence ages cluster at ∼5.9-3.3 ka, ∼1.2-1.1 ka (800-900 AD) and ∼190-120 years ago (1825-1895 AD) indicating times of middle and late Holocene sand sheet depositions and historical dune stabilization. The first age cluster indicates that beach sand accumulated when rates of global sea level rise declined around 6-5 ka. Until ∼4 ka sand sheets encroached up to 2.5 km inland. Historical and archaeological evidence points to sand mobilization since the first century AD. Sand sheets dating to 1.2-1.1 ka, coevally found throughout the dunefield represent sand stabilization due to vegetation reestablishment attributed to gradual and fluctuating decline in human activity from the middle Early Islamic period until the 10th century. Historical and chronological evidence of the existence of transverse and coppice dunes from the 19th century suggest that dunes only formed in the last few centuries. The study illustrates the initial role of natural processes, in this case decline in global sea level rise and the primary and later role of fluctuating human activity upon coastal sand mobility. The study distinguishes between sand sheets and dunes and portrays them as sensors of environmental changes.

  11. Consequences of pre-inoculation with native arbuscular mycorrhizae on root colonization and survival of Artemisia tridentata ssp. wyomingensis (Wyoming big sagebrush) seedlings after transplanting

    Science.gov (United States)

    Bill Eugene Davidson

    2015-01-01

    Inoculation of seedlings with arbuscular mycorrhizal fungi (AMF) is a common practice aimed at improving seedling establishment. The success of this practice largely depends on the ability of the inoculum to multiply and colonize the growing root system after transplanting. These events were investigated in Artemisia tridentata ssp. wyomingensis (Wyoming big sagebrush...

  12. Sea sand for reactive barriers

    International Nuclear Information System (INIS)

    Garcia R, G.; Ordonez R, E.; Ordonez R, En.

    2002-01-01

    Some phosphates have the property to suck in radioactive metals in solution, what it is taken in advance to make reactive barriers which are placed in the nuclear waste repositories. In an effort for contributing to the study of this type of materials, it has been obtained the zirconium silicate (ZrSiO 4 ) and the alpha zirconium hydrogen phosphate (Zr(HPO 4 ) 2H 2 O) starting from sea sand in an easy and economic way. (Author)

  13. Measurement and modelling of evapotranspiration in three fynbos vegetation types

    CSIR Research Space (South Africa)

    Dzikiti, Sebinasi

    2014-04-01

    Full Text Available sites. In this study we determined water use by 3 fynbos vegetation types growing at 4 different sites, namely: (i) lowland Atlantis Sand Plain fynbos growing on deep sandy soils, (ii) Kogelberg Sandstone fynbos growing in a riparian zone on deep...

  14. A Literature Survey on the Wetland Vegetation of Alaska.

    Science.gov (United States)

    1982-08-01

    filling. Reindeer were once herded for grazing on gravel areas near Barrow that are now devoid of vegetation. The coarse sand of a beach crest has a very...Tanana, and Porcupine . Thaw and oxbow lakes abound in the lowlands and moraine-dammed lakes are found in the mountains. During the Pleistocene

  15. Water repellency of clay, sand and organic soils in Finland

    Directory of Open Access Journals (Sweden)

    K. RASA

    2008-12-01

    Full Text Available Water repellency (WR delays soil wetting process, increases preferential flow and may give rise to surface runoff and consequent erosion. WR is commonly recognized in the soils of warm and temperate climates. To explore the occurrence of WR in soils in Finland, soil R index was studied on 12 sites of different soil types. The effects of soil management practice, vegetation age, soil moisture and drying temperature on WR were studied by a mini-infiltrometer with samples from depths of 0-5 and 5-10 cm. All studied sites exhibited WR (R index >1.95 at the time of sampling. WR increased as follows: sand (R = 1.8-5.0 < clay (R = 2.4-10.3 < organic (R = 7.9-undefined. At clay and sand, WR was generally higher at the soil surface and at the older sites (14 yr., where organic matter is accumulated. Below 41 vol. % water content these mineral soils were water repellent whereas organic soil exhibited WR even at saturation. These results show that soil WR also reduces water infiltration at the prevalent field moisture regime in the soils of boreal climate. The ageing of vegetation increases WR and on the other hand, cultivation reduces or hinders the development of WR.;

  16. Effect of compost on erodibility of loamy sand under simulated rainfall

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Cornelis, W.M.; Vermang, J.

    2011-01-01

    Three types of composts [vegetable, fruit and yard waste compost (VFYW), garden waste compost (GW), and spent mushroom compost (SM)] were applied at a rate of 30 m3 ha−1 for 10 years to loamy sand, to determine its effect on the aggregate stability and susceptibility to water erosion. Aggregate...... significant improvement for any of the compost types. SM application resulted in a significant increase (51%) in the shear strength of the soil after rainfall. Long term compost application does not appreciably improve the resistance of loamy sand to water erosion....

  17. Control of sand flies with attractive toxic sugar baits (ATSB) and potential impact on non-target organisms in Morocco.

    Science.gov (United States)

    Qualls, Whitney A; Müller, Gunter C; Khallaayoune, Khalid; Revay, Edita E; Zhioua, Elyes; Kravchenko, Vasiliy D; Arheart, Kristopher L; Xue, Rui-De; Schlein, Yosef; Hausmann, Axel; Kline, Daniel L; Beier, John C

    2015-02-08

    The persistence and geographical expansion of leishmaniasis is a major public health problem that requires the development of effective integrated vector management strategies for sand fly control. Moreover, these strategies must be economically and environmentally sustainable approaches that can be modified based on the current knowledge of sand fly vector behavior. The efficacy of using attractive toxic sugar baits (ATSB) for sand fly control and the potential impacts of ATSB on non-target organisms in Morocco was investigated. Sand fly field experiments were conducted in an agricultural area along the flood plain of the Ourika River. Six study sites (600 m x 600 m); three with "sugar rich" (with cactus hedges bearing countless ripe fruits) environments and three with "sugar poor" (green vegetation only suitable for plant tissue feeding) environments were selected to evaluate ATSB, containing the toxin, dinotefuran. ATSB applications were made either with bait stations or sprayed on non-flowering vegetation. Control sites were established in both sugar rich and sugar poor environments. Field studies evaluating feeding on vegetation treated with attractive (non-toxic) sugar baits (ASB) by non-target arthropods were conducted at both sites with red stained ASB applied to non-flowering vegetation, flowering vegetation, or on bait stations. At both the sites, a single application of ATSB either applied to vegetation or bait stations significantly reduced densities of both female and male sand flies (Phlebotomus papatasi and P. sergenti) for the five-week trial period. Sand fly populations were reduced by 82.8% and 76.9% at sugar poor sites having ATSB applied to vegetation or presented as a bait station, respectively and by 78.7% and 83.2%, respectively at sugar rich sites. The potential impact of ATSB on non-targets, if applied on green non-flowering vegetation and bait stations, was low for all non-target groups as only 1% and 0.7% were stained with non-toxic bait

  18. Indicators of ecosystem function identify alternate states in the sagebrush steppe.

    Science.gov (United States)

    Kachergis, Emily; Rocca, Monique E; Fernandez-Gimenez, Maria E

    2011-10-01

    Models of ecosystem change that incorporate nonlinear dynamics and thresholds, such as state-and-transition models (STMs), are increasingly popular tools for land management decision-making. However, few models are based on systematic collection and documentation of ecological data, and of these, most rely solely on structural indicators (species composition) to identify states and transitions. As STMs are adopted as an assessment framework throughout the United States, finding effective and efficient ways to create data-driven models that integrate ecosystem function and structure is vital. This study aims to (1) evaluate the utility of functional indicators (indicators of rangeland health, IRH) as proxies for more difficult ecosystem function measurements and (2) create a data-driven STM for the sagebrush steppe of Colorado, USA, that incorporates both ecosystem structure and function. We sampled soils, plant communities, and IRH at 41 plots with similar clayey soils but different site histories to identify potential states and infer the effects of management practices and disturbances on transitions. We found that many IRH were correlated with quantitative measures of functional indicators, suggesting that the IRH can be used to approximate ecosystem function. In addition to a reference state that functions as expected for this soil type, we identified four biotically and functionally distinct potential states, consistent with the theoretical concept of alternate states. Three potential states were related to management practices (chemical and mechanical shrub treatments and seeding history) while one was related only to ecosystem processes (erosion). IRH and potential states were also related to environmental variation (slope, soil texture), suggesting that there are environmental factors within areas with similar soils that affect ecosystem dynamics and should be noted within STMs. Our approach generated an objective, data-driven model of ecosystem dynamics

  19. Recursos vegetais usados por Acromyrmex striatus (Roger (Hymenoptera, Formicidae em restinga da Praia da Joaquina, Florianópolis, Santa Catarina, Brasil Vegetable resources used by Acromyrmex striatus (Roger (Hymenoptera, Formicidae in sand dunes at Joaquina Beach, Florianópolis, Santa Catarina State, Brazil

    Directory of Open Access Journals (Sweden)

    Benedito C. Lopes

    2005-06-01

    Full Text Available Foram amostrados 400 ninhos de Acromyrmex striatus entre 1997 e 1998, nas dunas da praia da Joaquina, Florianópolis, SC, para a verificação do material vegetal trazido para o ninho. Estas formigas usam partes de 50 espécies de plantas dispostas em 22 famílias, sendo as principais, representantes de Compositae, Gramineae e Leguminosae. Nesta última família, Stylosanthes viscosa foi a espécie mais utilizada nos dois anos de amostragem. Acromyrmex striatus corta matéria vegetal fresca, bem como se utiliza de material vegetal já caído, podendo, então se comportar como cortadeira ou como uma espécie oportunista.A total of 400 nests of Acromyrmex striatus (Roger, 1863 was evaluated between 1997 and 1998 at the dunes of the Joaquina Beach, Florianópolis, Santa Catarina State, in order to determine the vegetable substrate brought back to the nests. These ants use some parts of 50 plant species in 22 botanical families, being Compositae, Gramineae and Leguminosae the principal ones. In this last family, Stylosanthes viscosa Swartz was the most herbivored species in the two years samplings. Acromyrmex striatus cut fresh vegetables, as well as use decayed materials, being then a true leaf-cutter ant or a opportunistic ant.

  20. Using resistance and resilience concepts to reduce impacts of annual grasses and altered fire regimes on the sagebrush ecosystem and sage-grouse- A strategic multi-scale approach

    Science.gov (United States)

    Chambers, Jeanne C.; Pyke, David A.; Maestas, Jeremy D.; Boyd, Chad S.; Campbell, Steve; Espinosa, Shawn; Havlina, Doug; Mayer, Kenneth F.; Wuenschel, Amarina

    2014-01-01

    This Report provides a strategic approach for conservation of sagebrush ecosystems and Greater Sage- Grouse (sage-grouse) that focuses specifically on habitat threats caused by invasive annual grasses and altered fire regimes. It uses information on factors that influence (1) sagebrush ecosystem resilience to disturbance and resistance to invasive annual grasses and (2) distribution, relative abundance, and persistence of sage-grouse populations to develop management strategies at both landscape and site scales. A sage-grouse habitat matrix links relative resilience and resistance of sagebrush ecosystems with sage-grouse habitat requirements for landscape cover of sagebrush to help decision makers assess risks and determine appropriate management strategies at landscape scales. Focal areas for management are assessed by overlaying matrix components with sage-grouse Priority Areas for Conservation (PACs), breeding bird densities, and specific habitat threats. Decision tools are discussed for determining the suitability of focal areas for treatment and the most appropriate management treatments.

  1. Impacts of sand and dust storms on agriculture and potential agricultural applications of a SDSWS

    International Nuclear Information System (INIS)

    Stefanski, R; Sivakumar, M V K

    2009-01-01

    This paper will give an overview of the various impacts of sand and dust storms on agriculture and then address the potential applications of a Sand and Dust Storm Warning System (SDSWS) for agricultural users. Sand and dust storms have many negative impacts on the agricultural sector including: reducing crop yields by burial of seedlings under sand deposits, the loss of plant tissue and reduced photosynthetic activity as a result of sandblasting, delaying plant development, increasing end-of-season drought risk, causing injury and reduced productivity of livestock, increasing soil erosion and accelerating the process of land degradation and desertification, filling up irrigation canals with sediments, covering transportation routes, affecting water quality of rivers and streams, and affecting air quality. One positive impact is the fertilization of soil minerals to terrestrial ecosystems. There are several potential agricultural applications of a SDSWS. The first is to alert agricultural communities farmers to take preventive action in the near-term such as harvesting maturing crops (vegetables, grain), sheltering livestock, and strengthening infrastructure (houses, roads, grain storage) for the storm. Also, the products of a SDSWS could be used in for monitoring potential locust movement and post-storm crop damage assessments. An archive of SDSWS products (movement, amount of sand and dust) could be used in researching plant and animal pathogen movement and the relationship of sand and dust storms to disease outbreaks and in developing improved soil erosion and land degradation models.

  2. Projecting the Dependence of Sage-steppe Vegetation on Redistributed Snow in a Warming Climate.

    Science.gov (United States)

    Soderquist, B.; Kavanagh, K.; Link, T. E.; Seyfried, M. S.; Strand, E. K.

    2015-12-01

    In mountainous regions, the redistribution of snow by wind can increase the effective precipitation available to vegetation. Moisture subsidies caused by drifting snow may be critical to plant productivity in semi-arid ecosystems. However, with increasing temperatures, the distribution of precipitation is becoming more uniform as rain replaces drifting snow. Understanding the ecohydrological interactions between sagebrush steppe vegetation communities and the heterogeneous distribution of soil moisture is essential for predicting and mitigating future losses in ecosystem diversity and productivity in regions characterized by snow dominated precipitation regimes. To address the dependence of vegetation productivity on redistributed snow, we simulated the net primary production (NPP) of aspen, sagebrush, and C3 grass plant functional types spanning a precipitation phase (rain:snow) gradient in the Reynolds Creek Experimental Watershed and Critical Zone Observatory (RCEW-CZO). The biogeochemical process model Biome-BGC was used to simulate NPP at three sites located directly below snowdrifts that provide melt water late into the spring. To assess climate change impacts on future plant productivity, mid-century (2046-2065) NPP was simulated using the average temperature increase from the Multivariate Adaptive Constructed Analogs (MACA) data set under the RCP 8.5 emission scenario. At the driest site, mid-century projections of decreased snow cover and increased growing season evaporative demand resulted in limiting soil moisture up to 30 and 40 days earlier for aspen and sage respectively. While spring green up for aspen occurred an average of 13 days earlier under climate change scenarios, NPP remained negative up to 40 days longer during the growing season. These results indicate that the loss of the soil moisture subsidy stemming from prolonged redistributed snow water resources can directly influence ecosystem productivity in the rain:snow transition zone.

  3. The influence of environmental changes on local and regional vegetation patterns at Rieme (NW Belgium): implications for Final Palaeolithic habitation

    NARCIS (Netherlands)

    Bos, J.A.A.; Verbruggen, F.; Engels, S.; Crombé, P.

    2012-01-01

    Late-glacial vegetation changes were studied at Rieme, NW Belgium. Human occupation of this cover sand area occurred from the Final Palaeolithic onwards. The research area is situated on the northern side of a large cover sand ridge in an undulating landscape with small ridges and depressions. The

  4. Science framework for conservation and restoration of the sagebrush biome: Linking the Department of the Interior’s Integrated Rangeland Fire Management Strategy to long-term strategic conservation actions, Part 1. Science basis and applications

    Science.gov (United States)

    Chambers, Jeanne C.; Beck, Jeffrey L.; Bradford, John B.; Bybee, Jared; Campbell, Steve; Carlson, John; Christiansen, Thomas J; Clause, Karen J.; Collins, Gail; Crist, Michele R.; Dinkins, Jonathan B.; Doherty, Kevin E.; Edwards, Fred; Espinosa, Shawn; Griffin, Kathleen A.; Griffin, Paul; Haas, Jessica R.; Hanser, Steven E.; Havlina, Douglas W.; Henke, Kenneth F.; Hennig, Jacob D.; Joyce, Linda A; Kilkenny, Francis F.; Kulpa, Sarah M; Kurth, Laurie L; Maestas, Jeremy D; Manning, Mary E.; Mayer, Kenneth E.; Mealor, Brian A.; McCarthy, Clinton; Pellant, Mike; Perea, Marco A.; Prentice, Karen L.; Pyke, David A.; Wiechman , Lief A.; Wuenschel, Amarina

    2017-01-01

    The Science Framework is intended to link the Department of the Interior’s Integrated Rangeland Fire Management Strategy with long-term strategic conservation actions in the sagebrush biome. The Science Framework provides a multiscale approach for prioritizing areas for management and determining effective management strategies within the sagebrush biome. The emphasis is on sagebrush (Artemisia spp.) ecosystems and Greater sage-grouse (Centrocercus urophasianus). The approach provided in the Science Framework links sagebrush ecosystem resilience to disturbance and resistance to nonnative, invasive plant species to species habitat information based on the distribution and abundance of focal species. A geospatial process is presented that overlays information on ecosystem resilience and resistance, species habitats, and predominant threats and that can be used at the mid-scale to prioritize areas for management. A resilience and resistance habitat matrix is provided that can help decisionmakers evaluate risks and determine appropriate management strategies. Prioritized areas and management strategies can be refined by managers and stakeholders at the local scale based on higher resolution data and local knowledge. Decision tools are discussed for determining appropriate management actions for areas that are prioritized for management. Geospatial data, maps, and models are provided through the U.S. Geological Survey (USGS) ScienceBase and Bureau of Land Management (BLM) Landscape Approach Data Portal. The Science Framework is intended to be adaptive and will be updated as additional data become available on other values and species at risk. It is anticipated that the Science Framework will be widely used to: (1) inform emerging strategies to conserve sagebrush ecosystems, sagebrush dependent species, and human uses of the sagebrush system, and (2) assist managers in prioritizing and planning on-the-ground restoration and mitigation actions across the sagebrush biome.

  5. Studies in Phlebotomine Sand Flies.

    Science.gov (United States)

    1982-06-30

    Reporte de dos casos de [a ology of a sand fly, P/mlebolomu’,s diabolicuw Hall. in forma anergica difusa. Der matol. Rev. Mex. southwestern -Texas...Contribuiin al estudio de los Phmle- CDC, Veterinary Public Health Notes. USDHEW. bwmwnn de Costa Rica (Diptera, Psychodidae). Tesis. CDC. October. pp. 6- 7...janeiron R. j. 195 pp. the Unrited States (D1)pre ra: Psscfirdidae). j. Ortiz, 1. 1965a. Contribuci~in a! estudio tie los flebor- Partrsirtrl. 30:274-275

  6. Interactive effects between nest microclimate and nest vegetation structure confirm microclimate thresholds for Lesser Prairie-Chicken nest survival

    Science.gov (United States)

    Grisham, Blake A.; Godar, Alixandra J.; Boal, Clint W.; Haukos, David A.

    2016-01-01

    The range of Lesser Prairie-Chickens (Tympanuchus pallidicinctus) spans 4 unique ecoregions along 2 distinct environmental gradients. The Sand Shinnery Oak Prairie ecoregion of the Southern High Plains of New Mexico and Texas is environmentally isolated, warmer, and more arid than the Short-Grass, Sand Sagebrush, and Mixed-Grass Prairie ecoregions in Colorado, Kansas, Oklahoma, and the northeast panhandle of Texas. Weather is known to influence Lesser Prairie-Chicken nest survival in the Sand Shinnery Oak Prairie ecoregion; regional variation may also influence nest microclimate and, ultimately, survival during incubation. To address this question, we placed data loggers adjacent to nests during incubation to quantify temperature and humidity distribution functions in 3 ecoregions. We developed a suite of a priori nest survival models that incorporated derived microclimate parameters and visual obstruction as covariates in Program MARK. We monitored 49 nests in Mixed-Grass, 22 nests in Sand Shinnery Oak, and 30 nests in Short-Grass ecoregions from 2010 to 2014. Our findings indicated that (1) the Sand Shinnery Oak Prairie ecoregion was hotter and drier during incubation than the Mixed- and Short-Grass ecoregions; (2) nest microclimate varied among years within ecoregions; (3) visual obstruction was positively associated with nest survival; but (4) daily nest survival probability decreased by 10% every half-hour when temperature was greater than 34°C and vapor pressure deficit was less than −23 mmHg during the day (about 0600–2100 hours). Our major finding confirmed microclimate thresholds for nest survival under natural conditions across the species' distribution, although Lesser Prairie-Chickens are more likely to experience microclimate conditions that result in nest failures in the Sand Shinnery Oak Prairie ecoregion. The species would benefit from identification of thermal landscapes and management actions that promote cooler, more humid nest microclimates.

  7. The role of vegetation in shaping dune morphology

    Science.gov (United States)

    Duran Vinent, O.; Moore, L. J.; Young, D.

    2012-12-01

    Aeolian dunes naturally emerge under strong winds and sufficient sand supply. They represent the most dynamical feature of the arid and/or coastal landscape and their evolution has the potential to either increase desertification or reduce coastal vulnerability to storms. Although large-scale dune morphology mainly depends on the wind regime and sand availability, vegetation plays an important role in semiarid and/or coastal areas. It is well known that under certain conditions vegetation is able to stabilize dunes, driving a morphological transformation from un-vegetated mobile crescent dunes to static vegetated "parabolic" dunes, de facto paralyzing desertification and initiating land recovery. Furthermore, vegetation is also the primary ingredient in the formation of coastal foredunes, which determine vulnerability to storms, as low dunes are prone to storm-induced erosion and overwash. In both cases, the coupling of biological and geomorphic (physical) processes, in particular vegetation growth and sand transport, governs the evolution of morphology. These processes were implemented in a computational model as part of a previous effort. It was shown that, for a migrating dune, this coupling leads to a negative feedback for dune motion, where an ever denser vegetation implies ever lesser sand transport. The model also predicted the existence of a "mobility index", defined by the vegetation growth rate to sand erosion rate ratio, that fully characterizes the morphological outcome: for indices above a certain threshold biological processes are dominant and dune motion slows after being covered by plants; for lower indices, the physical processes are the dominant ones and the dune remains mobile while vegetation is buried or rooted out. Here, we extend this model to better understand the formation of coastal dunes. We include new physical elements such as the shoreline and water table, as well as different grass species and potential competition among them

  8. Galveston Island, Texas, Sand Management Strategies

    Science.gov (United States)

    2016-07-01

    billion m3 of beach quality sand . However, Texas projects to date have not utilized these sources because of transportation costs. The lack of nearby...estimate that the San Luis Pass flood shoal contains approximately 11.8 million yd3 of beach quality sand . However, it is expected that if permits...a source of beach- quality sand . 2. Sand could be intercepted before it reaches the present dry beach. ERDC/CHL TR-16-13 55 3. The volume of

  9. Crushed rock sand – An economical and ecological alternative to natural sand to optimize concrete mix

    Directory of Open Access Journals (Sweden)

    Sanjay Mundra

    2016-09-01

    Full Text Available The study investigates the use of crushed rock sand as viable alternative to Natural River sand that is being conventionally used as fine aggregate in cement concrete. Various mix designs were developed for different grades of concrete based on IS, ACI and British codes using Natural River sand and crushed rock sand. In each case, the cube compressive strength test, and beam flexure tests were conducted. The results of the study show that, the strength properties of concrete using crushed rock sand are nearly similar to the conventional concrete. The study has shown that crushed stone sand can be used as economic and readily available alternative to river sand and can therefore help to arrest the detrimental effects on the environment caused due to excessive mining of river sand.

  10. Lake Bathymetric Aquatic Vegetation

    Data.gov (United States)

    Minnesota Department of Natural Resources — Aquatic vegetation represented as polygon features, coded with vegetation type (emergent, submergent, etc.) and field survey date. Polygons were digitized from...

  11. The Holocene evolution of the beach and inland aeolian sand of the north-central Mediterranean coast of Israel

    Science.gov (United States)

    Roskin, Joel; Sivan, Dorit; Bookman, Revital; Shteinberg, Gilad

    2015-04-01

    distance and age and did not significantly differ from the values of beach sand. The spatial distribution and temporal clustering of the 1.2-1.1 ka ages does not seem stochastic. However, this age range does not coincide with any local or regional climate change or anthropogenic anomaly that could explain the enhanced sand mobility. Assuming no late Holocene change in coastal sand supply and availability, sand transport may have been due to short term climate (multi-annual) episodes of increased windiness that may have followed short-term or cumulative removal of stabilizing dune vegetation by man, a hypothesis that requires further investigation.

  12. Submarine sand ridges and sand waves in the eastern part of the China Sea

    Science.gov (United States)

    Wu, Ziyin; Li, Shoujun; Shang, Jihong; Zhou, Jieqiong; Zhao, Dineng; Liang, Yuyang

    2016-04-01

    Integrated with multi-beam and single-beam echo sounding data, as well as historical bathymetric data, submarine bathymetric maps of the eastern part of the China Sea, including the Bohai Sea, Huanghai Sea, and East China Sea, are constructed to systematically study submarine sand ridges and sand waves in the eastern part of the China Sea, combined with high-resolution seismic, sub-bottom profile and borehole data. Submarine sand ridges are extraordinarily developed in the eastern part of the China Sea, and 7 sand ridge areas can be divided from north to south, that is, the Laotieshan Channel sand ridge area in the Bohai Sea, the Korea Bay sand ridge area in the southern Huanghai Sea, the sand ridge area in the eastern Huanghai islands and the Huanghai Troughs, the Jianggang sand ridge area in the western Huanghai Sea, the sand ridge area in the East China Sea shelf, and the sand ridge and sand wave area in the Taiwan Strait and Taiwan Banks. The distribution area of the sand ridges and sand waves covers more than 450,000 km2, wherein ~10,000 km2 in the Bohai Bay, ~200,000 km2 in the Huanghai Sea, ~200,000 km2 in the East China Sea shelf, and ~40,000 km2 in the Taiwan Strait and Taiwan Banks, respectively. The great mass of sand ridges are distributed within water depth of 5-160 m, with a total length of over 160 km and a main width of 5-10 km. The inner structure of the sand ridges presents features of high-angle inclined beddings, with main lithology of sands, sand-mud alternations partly visible, and a small number of mud cores. Dating results indicate that the sand ridges in the eastern part of the China Sea are mainly developed in the Holocene. Sea-level variation dominates the sand ridge evolution in the eastern part of the China Sea since the LGM, and the sand ridges developed in the area of < 60m water depth are appeared in bad activity, meanwhile sand ridges with good activity are still developed in large scale.

  13. Fuel options for oil sands

    International Nuclear Information System (INIS)

    Wise, T.

    2005-01-01

    This presentation examined fuel options in relation to oil sands production. Options include steam and hydrogen (H 2 ) for upgrading; natural gas by pipeline; bitumen; petroleum coke; and coal. Various cost drivers were also considered for each of the fuel options. It was noted that natural gas has high energy value but the capital cost is low, and that coke's energy value is very low but the capital cost is high. A chart forecasting energy prices was presented. The disposition of Western Canada's northern gas situation was presented. Issues concerning rail transportation for coal were considered. Environmental concerns were also examined. A chart of typical gas requirements for 75,000 B/D oil sands projects was presented. Issues concerning steam generation with gas and mining cogeneration with gas fuel and steam turbines were discussed, as well as cogeneration and H 2 with gas fuels and steam turbines. Various technology and fuel utility options were examined, along with details of equipment and processes. Boiler technologies were reviewed by type as well as fuel and steam quality and pressure. Charts of cogeneration with gas turbine and circulation fluid bed boilers were presented. Gasification processes were reviewed and a supply cost basis was examined. Cost drivers were ranked according to energy, operating considerations and capital investment. Results indicated that fuel costs were significant for gas and coal. Capital costs and capital recovery charge was most significant with coal and gasification technology. Without capital recovery, cash costs favour the use of bitumen and coke. Gasification would need lower capital and lower capital recovery to compete with direct burning. It was concluded that direct burning of bitumen can compete with natural gas. With price volatility anticipated, dual fuel capability for bitumen and gas has merit. Petroleum coke can be produced or retrieved from stockpiles. Utility supply costs of direct burning of coke is

  14. Data resources for range-wide assessment of livestock grazing across the sagebrush biome

    Science.gov (United States)

    Assal, T.J.; Veblen, K.E.; Farinha, M.A.; Aldridge, Cameron L.; Casazza, Michael L.; Pyke, D.A.

    2012-01-01

    The data contained in this series were compiled, modified, and analyzed for the U.S. Geological Survey (USGS) report "Range-Wide Assessment of Livestock Grazing Across the Sagebrush Biome." This report can be accessed through the USGS Publications Warehouse (online linkage: http://pubs.usgs.gov/of/2011/1263/). The dataset contains spatial and tabular data related to Bureau of Land Management (BLM) Grazing Allotments. We reviewed the BLM national grazing allotment spatial dataset available from the GeoCommunicator National Integrated Land System (NILS) website in 2007 (http://www.geocommunicator.gov). We identified several limitations in those data and learned that some BLM State and/or field offices had updated their spatial data to rectify these limitations, but maintained the data outside of NILS. We contacted appropriate BLM offices (State or field, 25 in all) to obtain the most recent data, assessed the data, established a data development protocol, and compiled data into a topologically enforced dataset throughout the area of interest for this project (that is, the pre-settlement distribution of Greater Sage-Grouse in the Western United States). The final database includes three spatial datasets: Allotments (BLM Grazing Allotments), OUT_Polygons (nonallotment polygons used to ensure topology), and Duplicate_Polygon_Allotments. See Appendix 1 of the aforementioned report for complete methods. The tabular data presented here consists of information synthesized by the Land Health Standard (LHS) analysis (Appendix 2), and data obtained from the BLM Rangeland Administration System (http://www.blm.gov/ras/). In 2008, available LHS data for all allotments in all regions were compiled by BLM in response to a Freedom of Information Act (FOIA) request made by a private organization. The BLM provided us with a copy of these data. These data provided three major types of information that were of interest: (1) date(s) (if any) of the most recent LHS evaluation for each

  15. Biological soil crust formation under artificial vegetation effect and its properties in the Mugetan sandy land, northeastern Qinghai-Tibet Plateau

    Science.gov (United States)

    Li, Y. F.; Li, Z. W.; Jia, Y. H.; Zhang, K.

    2016-08-01

    Mugetan sandy land is an inland desertification area of about 2,065 km2 in the northeastern Qinghai-Tibet Plateau. In the ecological restoration region of the Mugetan sandy land, different crusts have formed under the action of vegetation in three types of sandy soil (i.e. semi-fixed sand dune, fixed sand dune and ancient fixed aeolian sandy soil). The surface sand particle distribution, mineral component and vegetation composition of moving sand dunes and three types of sandy soil were studied in 2010-2014 to analyze the biological crust formation properties in the Mugetan sandy land and the effects of artificial vegetation. Results from this study revealed that artificial vegetation increases the clay content and encourages the development of biological curst. The fine particles (i.e. clay and humus) of the surface layer of the sand dunes increased more than 15% ten years after the artificial vegetation planting, and further increased up to 20% after one hundred years. The interaction of clay, humus, and other fine particles formed the soil aggregate structure. Meanwhile, under the vegetation effect from the microbes, algae, and moss, the sand particles stuck together and a biological crust formed. The interconnection of the partial crusts caused the sand dunes to gradually be fixed as a whole. Maintaining the integrity of the biological crust plays a vital role in fixing the sand under the crust. The precipitation and temperature conditions in the Mugetan sandy land could satisfy the demand of biological crust formation and development. If rational vegetation measures are adopted in the region with moving sand dunes, the lichen-moss-algae biological curst will form after ten years, but it still takes more time for the sand dunes to reach the nutrient enrichment state. If the biological curst is partly broken due to human activities, reasonable closure and restoration measures can shorten the restoration time of the biological crust.

  16. Study of Black Sand Particles from Sand Dunes in Badr, Saudi Arabia Using Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Haider Abbas Khwaja

    2015-08-01

    Full Text Available Particulate air pollution is a health concern. This study determines the microscopic make-up of different varieties of sand particles collected at a sand dune site in Badr, Saudi Arabia in 2012. Three categories of sand were studied: black sand, white sand, and volcanic sand. The study used multiple high resolution electron microscopies to study the morphologies, emission source types, size, and elemental composition of the particles, and to evaluate the presence of surface “coatings or contaminants” deposited or transported by the black sand particles. White sand was comprised of natural coarse particles linked to wind-blown releases from crustal surfaces, weathering of igneous/metamorphic rock sources, and volcanic activities. Black sand particles exhibited different morphologies and microstructures (surface roughness compared with the white sand and volcanic sand. Morphological Scanning Electron Microscopy (SEM and Laser Scanning Microscopy (LSM analyses revealed that the black sand contained fine and ultrafine particles (50 to 500 nm ranges and was strongly magnetic, indicating the mineral magnetite or elemental iron. Aqueous extracts of black sands were acidic (pH = 5.0. Fe, C, O, Ti, Si, V, and S dominated the composition of black sand. Results suggest that carbon and other contaminant fine particles were produced by fossil-fuel combustion and industrial emissions in heavily industrialized areas of Haifa and Yanbu, and transported as cloud condensation nuclei to Douf Mountain. The suite of techniques used in this study has yielded an in-depth characterization of sand particles. Such information will be needed in future environmental, toxicological, epidemiological, and source apportionment studies.

  17. Understanding Colombian Amazonian white sand forests

    NARCIS (Netherlands)

    Peñuela-Mora, M.C.

    2014-01-01

    Although progress has been made in studies on white sand forests in the Amazon, there is still a considerable gap in our knowledge of the unique species composition of white sand forests and their structure and dynamics, especially in Western Amazon. This thesis aims to fill this gap by addressing

  18. Characterization of sand lenses embedded in tills

    DEFF Research Database (Denmark)

    Kessler, Timo Christian; Klint, K.E.S.; Nilsson, B.

    2012-01-01

    Tills dominate large parts of the superficial sediments on the Northern hemisphere. These glacial diamictons are extremely heterogeneous and riddled with fractures and lenses of sand or gravel. The frequency and geometry of sand lenses within tills are strongly linked to glaciodynamic processes...

  19. Japan's involvement in oil sands development

    International Nuclear Information System (INIS)

    Sugiura, T.

    1994-01-01

    According to Japanese national policy, exploration and development by Japanese companies in overseas countries are promoted in order to ensure stable oil supplies. Japan Canada Oil Sands Limited (JACOS), part of the JAPEX group, was established during the 1978 world oil crisis to explore and develop Canadian oil sand resources in accordance with Japan's national policy. The JAPEX group, including JACOS, has invested $123 million in oil sands projects in Alberta. JAPEX's first involvement in oil sands was in the Primrose Project operated by Norcen in the Cold Lake area. Five years of cyclic steam stimulation pilot tests did not produce sufficiently good results to justify further operation. The second involvement was the PCEJ Project, a joint effort by four companies that are participating in a bitumen recovery test project in the Athabasca Deposit. JACOS holds 2,452 km 2 of oil sands leases in Alberta. Tests conducted since 1978 in the PCEJ Project include multiwell steam injection pilot tests, some of which showed promise. JACOS is also participating in steam assisted gravity drainage projects and in federal/provincial research programs. Obstacles identified in developing Alberta oil sands are the lack of a bitumen pipeline to Edmonton and the insufficient length of oil sands leases (currently 10 years), given the difficulties of oil sand development. 10 figs

  20. Seasonal fluctuations of phlebotomines sand fly populations ...

    African Journals Online (AJOL)

    An entomological survey of phlebotomine sand flies was conducted in the Moulay Yacoub province, central Morocco. An anthropic niche (Ouled Aid) and a wild niche (Zliligh) were selected. Sand flies were collected twice a month between April 2011 and March 2012, using sticky traps and CDC light traps. 3675 specimens ...

  1. On shelterbelt design for combating sand invasion.

    NARCIS (Netherlands)

    Mohammed, A.E.; Stigter, C.J.; Adam, H.S.

    1996-01-01

    After a review of the scarce literature on using trees against sand encroachment, a quantitative experiment with a wide shelterbelt to combat sand invasion is reported on. Experimental work was carried out at the northwestern border of the Gezira Scheme (Sudan), an area of severe land degradation

  2. Design of dry sand soil stratified sampler

    Science.gov (United States)

    Li, Erkang; Chen, Wei; Feng, Xiao; Liao, Hongbo; Liang, Xiaodong

    2018-04-01

    This paper presents a design of a stratified sampler for dry sand soil, which can be used for stratified sampling of loose sand under certain conditions. Our group designed the mechanical structure of a portable, single - person, dry sandy soil stratified sampler. We have set up a mathematical model for the sampler. It lays the foundation for further development of design research.

  3. Pattern formation - Instabilities in sand ripples

    DEFF Research Database (Denmark)

    Hansen, J. L.; v. Hecke, M.; Haaning, A.

    2001-01-01

    Sand ripples are seen below shallow wavy water and are formed whenever water oscillates over a bed of sand. Here we analyse the instabilities that can upset this perfect patterning when the ripples are subjected to large changes in driving amplitude or frequency, causing them to deform both...

  4. Streamflow measurements in the oil sands region of northeastern Alberta[General Conference

    Energy Technology Data Exchange (ETDEWEB)

    Ashiq, M.; Ade, F. [Golder Associates Ltd., Calgary, AB (Canada). Water Resources Engineering Group

    2006-07-01

    Oil sands mining in the muskeg terrain of north-eastern Alberta will result in changes to the natural landscape, including changes to the morphology of receiving streams. The streams in the oil sands region are fed by constricted flows through the muskeg terrain. The roughness of the stream is attributed to sporadic cobbles and boulders, in-stream vegetation, over hanging vegetation and large quantities of wooden debris from beaver activities. This paper discussed stream roughness features in the oil sands region and compared the velocity profiles in these streams to the normal channel velocity profile. The study also included a comparison of computed discharges based on a simple method and a detailed method. The sources of errors in velocity measurements were then discussed. It was noted that before any oil sand mining project is approved, flows in receiving streams are monitored as part of the Environment Impact Assessment (EIA). The flows are then monitored again after project approval as part of project approval conditions.

  5. Flowability in crushed sand mortar

    Directory of Open Access Journals (Sweden)

    Cabrera, O. A.

    2010-12-01

    Full Text Available The present experimental study explored the relationship between mortar flowability and the voids content in crushed sand to determine the effect of grain shape and surface texture as well as dust content on the behaviour of fresh mortar. The findings revealed a close correlation between voids content and the volume of paste needed for mortar to begin to flow as a continuous material, mortar flowability and the water content needed to attain a given flowability. The comparison of the empirical findings to the results obtained with the Larrard (1, 2 model provided further information on the effect of sand grain morphology on fresh mortars.

    En el presente trabajo se plantea un estudio experimental de la fluidez de morteros basado en el contenido de vacíos de arenas machacadas, para comprender la influencia de la forma y textura superficial de los granos de arena y del contenido de polvo de las mismas sobre el estado fresco de morteros. Los resultados muestran la estrecha relación entre el contenido de vacíos entre granos y los volúmenes de pasta necesarios para iniciar el escurrimiento como un material continuo, la fluidez de los morteros, el contenido de agua para alcanzar una determinada fluidez, etc. El comportamiento evaluado se compara con resultados obtenidos aplicando el modelo de F. de Larrard (1, 2, permitiendo de este modo obtener mayor información de la influencia de la morfología de los granos de la arena sobre el estado fresco de los morteros.

  6. Sand transportation and reverse patterns over leeward face of sand dune

    Science.gov (United States)

    Jiang, Hong; Dun, Hongchao; Tong, Ding; Huang, Ning

    2017-04-01

    Sand saltation has complex interactions with turbulent flow and dune form. Most models of wind-blown sand consider ideal circumstances such as steady wind velocity and a flat surface, and the bulk of data on wind flow and sand transport over an individual dune has focused mostly on the influence of dune shape or inter-dune space on the wind flow, neglecting the effect of morphology on sand saltation, particularly airflow and sand transportation over the leeward slope. Wind flow structures over the leeward slope of sand dunes have a fundamental influence on the organization of sand dunes. In order to understand sand dune dynamics, lee face airflow and sediment transportation should be paid more attention. Previous field observations could not measure turbulent flow structure well because of the limited observation points and the influence of experiment structure on wind field. In addition, the reverse sand particles over leeward face could not be collected by sand trap in field. Numerous field observations could not measure turbulent flow structure because of the limited observation points and the influence of experimental structures on the wind field. In addition, the reverse transport of sand particles over leeward face could not be collected by sand traps in field. Therefore, this paper aims to investigate the turbulent flow structure and sand transport pattern over the leeward slope. A numerical model of sand saltation over slope terrain is constructed, which also considers the coupling effects between air flow and sand particles. The large eddy simulation method is used to model turbulent flow. Sand transport is simulated by tracking the trajectory of each sand particle. The results show that terrain significantly alters the turbulent air flow structure and wind-blown sand movement, especially over the leeward slope. Here, mass flux increases initially and then decreases with height in the reversed flow region in the direction of wind flow, and the mass flux

  7. Mineral weathering experiments to explore the effects of vegetation shifts in high mountain region (Wind River Range, Wyoming, USA)

    Science.gov (United States)

    Mavris, Christian; Furrer, Gerhard; Dahms, Dennis; Anderson, Suzanne P.; Blum, Alex; Goetze, Jens; Wells, Aaron; Egli, Markus

    2015-04-01

    Climate change influences the evolution of soil and landscape. With changing climate, both flora and fauna must adapt to new conditions. It is unknown in many respects to what extent soils will react to warming and vegetation change. The aim of this study was to identify possible consequences for soils in a dry-alpine region with respect to weathering of primary minerals and leaching of elements under expected warming climate conditions due to shifts in vegetation. To achieve this, a field empirical approach was used in combination with laboratory weathering experiments simulating several scenarios. Study sites located in Sinks Canyon and in Stough Basin of the Wind River Range, Wyoming, USA, encompass ecotones that consist of tundra, forest, or sagebrush (from moist to dry, with increasing temperature, respectively). All soils are developed on granitoid moraines. The mineralogy of the soils along the altitudinal sequence was analysed using cathodoluminescence and X-ray diffraction, and revealed clear mineral transformations: biotite and plagioclase were both weathered to smectite while plagioclase also weathered to kaolinite. Cooler, wetter, altitude-dependent conditions seemed to promote weathering of these primary minerals. To test the impact of soil solutions from different ecotones on mineral weathering, aqueous extracts from topsoils (A horizons) were reacted with subsoils (B horizons) in batch experiments. Aqueous extracts of topsoil samples were generated for all three ecotones, and these solutions were characterized. For the batch experiments, the topsoil extracts were reacted for 1800 hours with the subsoil samples of the same ecotone, or with the subsoil samples from higher altitude ecotones. Solutions collected periodically during the experiments were measured using ICP-OES and ion chromatography. Dissolved Ca, Mg and K were mainly controlled by the chemical weathering of oligoclase, K-feldspar and biotite. With increasing altitude (and consequently

  8. Factors influencing the natural regeneration of the pioneering shrub Calligonum mongolicum in sand dune stabilization plantations in arid deserts of northwest China.

    Science.gov (United States)

    Fan, Baoli; McHugh, Allen David; Guo, Shujiang; Ma, Quanlin; Zhang, Jianhui; Zhang, Xiaojuan; Zhang, Weixing; Du, Juan; Yu, Qiushi; Zhao, Changming

    2018-03-01

    Calligonum mongolicum is a successful pioneer shrub to combat desertification, which is widely used for vegetation restoration in the desert regions of northwest China. In order to reveal the limitations to natural regeneration of C. mongolicum by asexual and sexual reproduction, following the process of sand dune stabilization, we assessed clonal shoots, seedling emergence, soil seed bank density, and soil physical characteristics in mobile and stabilized sand dunes. Controlled field and pot experiments were also conducted to assess germination and seedling emergence in different dune soil types and seed burial depths. The population density of mature C. mongolicum was significantly different after sand dune stabilization. Juvenile density of C. mongolicm was much lower in stabilized sand dunes than mobile sand dune. There was no significant difference in soil seed bank density at three soil depths between mobile and stabilized sand dunes, while the emergence of seedlings in stabilized dunes was much lower than emergence in mobile dunes. There was no clonal propagation found in stabilized dunes, and very few C. mongolicum seedlings were established on stabilized sand dunes. Soil clay and silt content, air-filled porosity, and soil surface compaction were significantly changed from mobile sand dune to stabilized dunes. Seedling emergence of C. mongolicm was highly dependent on soil physical condition. These results indicated that changes in soil physical condition limited clonal propagation and seedling emergence of C. mongolicum in stabilized sand dunes. Seed bank density was not a limiting factor; however, poor seedling establishment limited C. mongolicum's further natural regeneration in stabilized sand dunes. Therefore, clonal propagation may be the most important mode for population expansion in mobile sand dunes. As a pioneer species C. mongolicum is well adapted to propagate in mobile sand dune conditions, it appears unlikely to survive naturally in

  9. Developing new markets for oil sands products

    International Nuclear Information System (INIS)

    Crandall, G.

    2004-01-01

    This paper presents a review by Purvin and Gertz of western Canadian crude oil supply. This energy consulting firm provides advise to the energy sector. It suggests that oil sands production will surpass declining conventional production. Oil sands supply includes bitumen, synthetic crude oil (SCO), and diluent. It is forecasted that oil sands will increase from 42 per cent of western supply in 2002 to 78 per cent in 2015. The potential of Alberta's oil sands was discussed along with a recent study of refined products and petrochemicals from bitumen. Upgrading, refining and petrochemical case studies were presented. The author examined if a Canadian oil sands upgrading project with high capital costs can be competitive with competing projects in the United States and internationally. In addition to supply and demand issues, the presentation examined infrastructure capability and market potential in the United States. The economic potential and risks of preferred business cases compared to upgrading to SCO were also evaluated. 15 figs

  10. Numerical simulation of aeolian sand ripples

    International Nuclear Information System (INIS)

    Kang Liqiang; Guo Liejin

    2004-01-01

    With a new horizontal saltation displacement vector, a model is implemented to simulate the initiation and evolution of aeolian sand ripples. In the model, saltation distance considers the effects of surface height and slope. A linear stability analysis is also carried out for formation of sand ripples. The results show that, the model can be able to successfully reproduce sand ripples which can increase in scale by merging of small ripples. The linear stability analysis indicates that sand ripples appear when the relaxation rate parameter is below a threshold value and wind strength parameter is larger than a critical value. The results also verified that the formation of sand ripples is a self-organization process

  11. Data Report: Meteorological and Evapotranspiration Data from Sagebrush and Pinyon Pine/Juniper Communities at Pahute Mesa, Nevada National Security Site, 2011-2012

    Energy Technology Data Exchange (ETDEWEB)

    Jasoni, Richard L [DRI; Larsen, Jessica D [DRI; Lyles, Brad F. [DRI; Healey, John M [DRI; Cooper, Clay A [DRI; Hershey, Ronald L [DRI; Lefebre, Karen J [DRI

    2013-04-01

    Pahute Mesa is a groundwater recharge area at the Nevada National Security Site. Because underground nuclear testing was conducted at Pahute Mesa, groundwater recharge may transport radionuclides from underground test sites downward to the water table; the amount of groundwater recharge is also an important component of contaminant transport models. To estimate the amount of groundwater recharge at Pahute Mesa, an INFIL3.0 recharge-runoff model is being developed. Two eddy covariance (EC) stations were installed on Pahute Mesa to estimate evapotranspiration (ET) to support the groundwater recharge modeling project. This data report describes the methods that were used to estimate ET and collect meteorological data. Evapotranspiration was estimated for two predominant plant communities on Pahute Mesa; one site was located in a sagebrush plant community, the other site in a pinyon pine/juniper community. Annual ET was estimated to be 310±13.9 mm for the sagebrush site and 347±15.9 mm for the pinyon pine/juniper site (March 26, 2011 to March 26, 2012). Annual precipitation measured with unheated tipping bucket rain gauges was 179 mm at the sagebrush site and 159 mm at the pinyon pine/juniper site. Annual precipitation measured with bulk precipitation gauges was 222 mm at the sagebrush site and 227 mm at the pinyon pine/juniper site (March 21, 2011 to March 28, 2012). A comparison of tipping bucket versus bulk precipitation data showed that total precipitation measured by the tipping bucket rain gauges was 17 to 20 percent lower than the bulk precipitation gauges. These differences were most likely the result of the unheated tipping bucket precipitation gauges not measuring frozen precipitation as accurately as the bulk precipitation gauges. In this one-year study, ET exceeded precipitation at both study sites because estimates of ET included precipitation that fell during the winter of 2010-2011 prior to EC instrumentation and the precipitation gauges started

  12. Genotype, soil type, and locale effects on reciprocal transplant vigor, endophyte growth, and microbial functional diversity of a narrow sagebrush hybrid zone in Salt Creek Canyon, Utah

    Science.gov (United States)

    Miglia, K.J.; McArthur, E.D.; Redman, R.S.; Rodriguez, R.J.; Zak, J.C.; Freeman, D.C.

    2007-01-01

    When addressing the nature of ecological adaptation and environmental factors limiting population ranges and contributing to speciation, it is important to consider not only the plant's genotype and its response to the environment, but also any close interactions that it has with other organisms, specifically, symbiotic microorganisms. To investigate this, soils and seedlings were reciprocally transplanted into common gardens of the big sagebrush hybrid zone in Salt Creek Canyon, Utah, to determine location and edaphic effects on the fitness of parental and hybrid plants. Endophytic symbionts and functional microbial diversity of indigenous and transplanted soils and sagebrush plants were also examined. Strong selection occurred against the parental genotypes in the middle hybrid zone garden in middle hybrid zone soil; F1 hybrids had the highest fitness under these conditions. Neither of the parental genotypes had superior fitness in their indigenous soils and habitats; rather F1 hybrids with the nonindigenous maternal parent were superiorly fit. Significant garden-by-soil type interactions indicate adaptation of both plant and soil microorganisms to their indigenous soils and habitats, most notably in the middle hybrid zone garden in middle hybrid zone soil. Contrasting performances of F1 hybrids suggest asymmetrical gene flow with mountain, rather than basin, big sagebrush acting as the maternal parent. We showed that the microbial community impacted the performance of parental and hybrid plants in different soils, likely limiting the ranges of the different genotypes.

  13. Susceptibility and antibody response of Vesper Sparrows (Pooecetes gramineus) to West Nile virus: A potential amplification host in sagebrush-grassland habitat

    Science.gov (United States)

    Hofmeister, Erik K.; Dusek, Robert J.; Fassbinder-Orth, Carol; Owen, Benjamin; Franson, J. Christian

    2016-01-01

    West Nile virus (WNV) spread to the US western plains states in 2003, when a significant mortality event attributed to WNV occurred in Greater Sage-grouse ( Centrocercus urophasianus ). The role of avian species inhabiting sagebrush in the amplification of WNV in arid and semiarid regions of the North America is unknown. We conducted an experimental WNV challenge study in Vesper Sparrows ( Pooecetes gramineus ), a species common to sagebrush and grassland habitats found throughout much of North America. We found Vesper Sparrows to be moderately susceptible to WNV, developing viremia considered sufficient to transmit WNV to feeding mosquitoes, but the majority of birds were capable of surviving infection and developing a humoral immune response to the WNV nonstructural 1 and envelope proteins. Despite clearance of viremia, after 6 mo, WNV was detected molecularly in three birds and cultured from one bird. Surviving Vesper Sparrows were resistant to reinfection 6 mo after the initial challenge. Vesper sparrows could play a role in the amplification of WNV in sagebrush habitat and other areas of their range, but rapid clearance of WNV may limit their importance as competent amplification hosts of WNV.

  14. Critical State of Sand Matrix Soils

    Science.gov (United States)

    Marto, Aminaton; Tan, Choy Soon; Makhtar, Ahmad Mahir; Kung Leong, Tiong

    2014-01-01

    The Critical State Soil Mechanic (CSSM) is a globally recognised framework while the critical states for sand and clay are both well established. Nevertheless, the development of the critical state of sand matrix soils is lacking. This paper discusses the development of critical state lines and corresponding critical state parameters for the investigated material, sand matrix soils using sand-kaolin mixtures. The output of this paper can be used as an interpretation framework for the research on liquefaction susceptibility of sand matrix soils in the future. The strain controlled triaxial test apparatus was used to provide the monotonic loading onto the reconstituted soil specimens. All tested soils were subjected to isotropic consolidation and sheared under undrained condition until critical state was ascertain. Based on the results of 32 test specimens, the critical state lines for eight different sand matrix soils were developed together with the corresponding values of critical state parameters, M, λ, and Γ. The range of the value of M, λ, and Γ is 0.803–0.998, 0.144–0.248, and 1.727–2.279, respectively. These values are comparable to the critical state parameters of river sand and kaolin clay. However, the relationship between fines percentages and these critical state parameters is too scattered to be correlated. PMID:24757417

  15. Oil Sands Regional Aquatics Monitoring Program (RAMP) 5 year report

    International Nuclear Information System (INIS)

    Fawcett, K.

    2003-05-01

    This 5 year report outlined and examined the activities of the Regional Aquatics Monitoring Program (RAMP) from its introduction in 1997 up to 2001. The RAMP is a multi-stakeholder program comprised of industry and government representatives as well as members of aboriginal groups and environmental organizations. The objectives of RAMP are to monitor aquatic environments in the oil sands region in order to allow for assessment of regional trends and cumulative effects, as well as to provide baseline data against which impact predictions of recent environmental impact assessments can be verified. Scientific programs conducted as part of RAMP during the 5-year period included water quality and sediment quality analyses; fish monitoring; benthic communities monitoring; water quality and aquatic vegetation analyses of wetlands; and hydrology and climate monitoring. RAMP's programs have expanded annually in scope as a result of increased oil sands development in the region. This report provided outlines of RAMP's individual program objectives and organizational structures, as well as details of all studies conducted for each year. Data were collected for all major study areas were presented, and program methodologies for assessing and identifying trends were outlined. refs., tabs., figs

  16. Drivers of drift sand dynamics; a reconstruction for the Wekeromse Zand, the Netherlands

    Science.gov (United States)

    Hendriks, Chantal; Sonneveld, Marthijn; Wallinga, Jakob

    2013-04-01

    Inland active drift sand landscapes are regarded as unique ecosystems of great historical and geomorphological value. Recent studies have highlighted the role of multiple factors in the initiation and stabilization of drift sand landscapes. To unravel the importance of different forcings (e.g. agricultural practices, climate) and their interplay, insight in the chronology of drift sand dynamics is essential. In this study, we aimed to reconstruct the dynamics of the drift sand landscape of the Wekeromse Zand (central Netherlands) and to develop a conceptual model to understand the processes involved. The Wekeromse Zand study area (370 ha) is located on the border of a central push moraine and is characterised by open active drift sands (14 ha) and vegetated hills and valleys. The surroundings are dominated by modern agricultural practices, and remnants from ancient iron age Celtic Field systems showing that the area has been in agricultural use since at least the Iron Age. For the study area we: i) analysed historical maps going back to the early 19th century, ii) performed a field survey to map the palaeolandscape (before drift sand activation) and iii) employed optically stimulated luminescence (OSL) dating of drift sand deposits on 11 samples from two locations to determine the timing of drift sand deposition. Analysis of the available topographic maps showed no substantial aeolean activity of the area outside its morphological boundaries. OSL dating revealed that two drift sand layers were deposited between 1373 and 1462 AD and between 1680 and 1780 AD. A layer with a higher organic matter content was found at one of the sites. This suggests that the Wekeromse Zand has known three relatively stable periods: i) a period between the start of the Holocene to the Late Medieval Period, ii) in between the Medieval climatic optimum and the climatic Maunder minimum, and iii) current situation. Despite the fact that agricultural activities occurred in this area from the

  17. Habitat analysis of North American sand flies near veterans returning from leishmania-endemic war zones

    Directory of Open Access Journals (Sweden)

    Keep Lisa

    2008-12-01

    Full Text Available Abstract Background Nearly 1300 cases of leishmaniasis have been identified in American military personnel deployed to Iraq and Afghanistan. The symptoms of this disease can range from a mild, self-limiting cutaneous infection to a deadly visceral infection and are not prevented by chemoprophylaxis or immunization. Effective treatments, however, are available. The disease-causing parasite is spread through the bite of the female sand fly. Although the disease occurs in both the Old World and the New World, the parasite species differ between the hemispheres. The large number of cases in military veterans has caused some concern that Old World, temperate-adapted parasite species could be introduced into the native sand fly populations of American military facilities where veterans of the current conflicts return following their deployments. This paper reports part of a larger study to analyze the risk of such an accidental importation. Four potential habitats on two large Army facilities in the Southeast United States were surveyed to determine relative sand fly density. The National Land Cover Map was used to provide sand fly density prediction maps by habitat. Results Sand fly density was significantly higher in deciduous forest and even higher at the interface between forest and open grassland. The evergreen forest and agricultural fields supported very low densities. On Fort Campbell, KY, the percentage of land covered by suitable habitat was very high. A sand fly density prediction map identified large tracts of land where infected individuals would be at higher risk of exposure to sand fly bites, resulting in an increased risk of introducing the parasite to a native insect population. On Fort Bragg, NC, however, commercial farming of long leaf pine reduced the percentage of the land covered in vegetation suitable for the support of sand flies. The risk of introducing an exotic Leishmania spp. on Fort Bragg, therefore, is considered to be

  18. Watching Faults Grow in Sand

    Science.gov (United States)

    Cooke, M. L.

    2015-12-01

    Accretionary sandbox experiments provide a rich environment for investigating the processes of fault development. These experiments engage students because 1) they enable direct observation of fault growth, which is impossible in the crust (type 1 physical model), 2) they are not only representational but can also be manipulated (type 2 physical model), 3) they can be used to test hypotheses (type 3 physical model) and 4) they resemble experiments performed by structural geology researchers around the world. The structural geology courses at UMass Amherst utilize a series of accretionary sandboxes experiments where students first watch a video of an experiment and then perform a group experiment. The experiments motivate discussions of what conditions they would change and what outcomes they would expect from these changes; hypothesis development. These discussions inevitably lead to calculations of the scaling relationships between model and crustal fault growth and provide insight into the crustal processes represented within the dry sand. Sketching of the experiments has been shown to be a very effective assessment method as the students reveal which features they are analyzing. Another approach used at UMass is to set up a forensic experiment. The experiment is set up with spatially varying basal friction before the meeting and students must figure out what the basal conditions are through the experiment. This experiment leads to discussions of equilibrium and force balance within the accretionary wedge. Displacement fields can be captured throughout the experiment using inexpensive digital image correlation techniques to foster quantitative analysis of the experiments.

  19. Sudan challenges the sand dragon.

    Science.gov (United States)

    Tinker, J

    1978-01-01

    Formerly productive areas have become wasteland as the desert advances in the Sudan. To understand how desertification is undermining the very survival of the Sahel, one ecosystem is reviewed in detail here: the gum arabic zone of Kordofan. After cotton, gum arabic is Sudan's largest export, worth from $14-26 million in recent years. In this zone the ecologically balanced cycle of gum gardens, fire, grain crops, and fallow is now breaking down; the 1968-1973 drought having in many areas delivered the final blow. Because of a growing population, the cultivation period is extended, and the soil becomes impoverished. Overgrazing in the fallow period, and the lopping of gum trees for firewood is producing a low return on the gum trees. Without this gum to harvest for cash, farmers must repeatedly replant their subsistence crops until the land becomes useless sand. The Sudanese have recognized the problem earlier than most, and a number of imaginative and practicable pilot projects are already in use: 1) waterpoint management; 2) construction of firebreaks; 3) land threatened by shifting dunes has been enclosed by stockproof fence and afforested with local trees; and 4) shelter belts have been planted around town perimeters where old gum tree stumps have started to sprout and the grass is reseeding itself. Out of these pilot projects, and with the advice of the U.N. Environment Program, the U.N. Development Program, and FAO, the Sudanese have developed a modest $26 million desert encroachment control and rehabilitation program (DECARP).

  20. Sand to Root Transfer of PAHs and PCBs by Carrots Grown on Sand with Pure Substances and Biosolids Amended Sand

    OpenAIRE

    Sablayrolles, Caroline; Montréjaud-Vignoles, Mireille; Silvestre, Jérôme; Patria, Lucie

    2006-01-01

    A study on behaviour of trace organic compounds (Polycyclic Aromatic Hydrocarbons, PAH, and Polychlorinated Biphenyls, PCB) in a sand-plant system has been carried out, with the reclamation of wastewater treatment plant biosolids for agriculture in mind. Carrot plants (Daucus carota) were grown on soilless culture (sand), to provide optimal transfer conditions, in plant containers inside a temperature regulated greenhouse. There were two types of experiment. The trace organic compounds have i...

  1. Vegetation dynamics and dynamic vegetation science

    NARCIS (Netherlands)

    Van der Maarel, E

    1996-01-01

    his contribution presents a review of the development of the study of vegetation dynamics since 1979, in the framework of a jubilee meeting on progress in the study of vegetation. However, an exhaustive review is both impossible and unnecessary. It is impossible within the few pages available

  2. Evaluating greater sage-grouse seasonal space use relative to leks: Implications for surface use designations in sagebrush ecosystems

    Science.gov (United States)

    Casazza, Michael L.; Coates, Peter S.

    2013-01-01

    The development of anthropogenic structures, especially those related to energy resources, in sagebrush ecosystems is an important concern among developers, conservationists, and land managers in relation to greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) populations. Sage-grouse are dependent on sagebrush ecosystems to meet their seasonal life-phase requirements, and research indicates that anthropogenic structures can adversely affect sage-grouse populations. Land management agencies have attempted to reduce the negative effects of anthropogenic development by assigning surface use (SU) designations, such as no surface occupancy, to areas around leks (breeding grounds). However, rationale for the size of these areas is often challenged. To help inform this issue, we used a spatial analysis of sage-grouse utilization distributions (UDs) to quantify seasonal (spring, summer and fall, winter) sage-grouse space use in relation to leks. We sampled UDs from 193 sage-grouse (11,878 telemetry locations) across 4 subpopulations within the Bi-State Distinct Population Segment (DPS, bordering California and Nevada) during 2003–2009. We quantified the volume of each UD (vUD) within a range of areas that varied in size and were centered on leks, up to a distance of 30 km from leks. We also quantified the percentage of nests within those areas. We then estimated the diminishing gains of vUD as area increased and produced continuous response curves that allow for flexibility in land management decisions. We found nearly 90% of the total vUD (all seasons combined) was contained within 5 km of leks, and we identified variation in vUD for a given distance related to season and migratory status. Five kilometers also represented the 95th percentile of the distribution of nesting distances. Because diminishing gains of vUD was not substantial until distances exceeded 8 km, managers should consider the theoretical optimal distances for SU designation

  3. experimental studies of sand production from unconsolidated

    African Journals Online (AJOL)

    ES Obe

    aDepartment of Chemical Engineering, University of Lagos, Lagos, Nigeria. bDepartment of Petroleum ... as risk of well failure, erosion of pipelines and surface facilities, sand separa- ... ment, theoretical and numerical analysis have lead to the ...

  4. A study of global sand seas

    Science.gov (United States)

    McKee, Edwin D.

    1979-01-01

    The birth of the idea that led to this publication on "Global Sand Seas" dates back to the late 1920's. At that time I was engaged in a study of the Coconino Sandstone of Arizona's Grand Canyon. Considerable controversy existed then as to whether this sandstone was a subaqueous deposit or was composed of wind-formed dunes. It became apparent that definitive literature was sparse or lacking on types of dunes, global distribution of these types, the mechanics of their development, the precise nature of their internal structure of cross-stratificiation, and the relation of wind systems to these sand forms. Especially lacking were data on criteria that could confidently be used in the recognition of ancient dunes. The common denominator in this publication is eolian sand bodies. Although the book is concerned primarily with desert sand seas, the subject matter is not restricted to deserts; it includes many references to deposits of coastal sand and to sand bodies in humid climates. Nor does the book deal exclusively with dunes, which, according to most definitions, involve mounds or hills. Many references are made to sand sheets, sand stringers, and other types of sand deposits that have no prominent topographic expression. All sand bodies accumulated by the action of wind are discussed. Chapters A-J of this publication are primarily topical. Chapters cover the grain texture, the color, and the structure of modern dunes and other eolian sands. Special treatment is given to the relation of wind data to dune interpretation, the evolution of form in current-deposited sand bodies as determined from experimental studies, and the discriminant analysis technique for differentiating between coastal and inland desert sands. This topical part of the publication also includes an analysis of criteria used in ancient deposits to interpret their eolian genesis and a consideration of economic application of the principles described, including a discussion of potentials and problems

  5. Bioaugmentation of flow-through sand filters

    DEFF Research Database (Denmark)

    Samuelsen, Elin Djurhuus

    for degradation performances in flow-through sand columns, with the aim of identifying a suitable inoculant strain for future environmental applications. Another aim was to identify a suitable genetic marker to monitor phenoxy acid degradation in strain Sphingobium sp. PM2. We were not able to link motility...... and biofilm formation to the strains´ ability to adhere to sand. Nevertheless, a correlation was found between cell surface hydrophobicity and adhesion and overall degradation performances in flow-through sand columns. We identified S phingobium sp. PM2 as a promising inoculant strain, displaying efficient...... MCPA degradation for prolonged periods in flow-through sand columns. In an expression study of catabolic genes with putative roles in phenoxy acid degradation, we observed a marked upregulation of catabolic genes cadA and tfdC upon exposure to MCPA, 2,4-D, dichlorprop and mecoprop in strain PM2, which...

  6. Geotechnical properties of crude oil contaminated sand

    International Nuclear Information System (INIS)

    Puri, V.K.; Das, B.M.; Cook, E.E.; Shin, E.C.

    1994-01-01

    Contamination of soil due to an oil spill influences its subsequent engineering behavior. An investigation was conducted to study the effect of crude oil contamination on compaction characteristics, shear strength, one-dimensional compression, and coefficient of permeability. Water permeability was also determined by using commercial grade motor oils as contaminants. The test results indicate that the compaction characteristics are influenced by oil contamination. The angle of internal friction of sand (based on total stress condition) decreases due to presence of oil within the pore spaces in sand. One dimensional compression characteristics of sand are significantly influenced by oil contamination resulting in a decrease in the value of constrained modulus with increase in the degree of oil contamination compared to the case of dry sand. Water permeability was observed to be a function of the initial viscosity and the degree of saturation due to the contaminating oil

  7. Displacement pile installation effects in sand

    NARCIS (Netherlands)

    Beijer-Lundberg, A.

    2015-01-01

    Installation effects govern the post-installation behaviour of displacement piles in sand. These effects are currently not completely understood. Suitable experimental techniques to model these installation effects include field, laboratory and experimental models. In the current thesis a

  8. Fruits and vegetables (image)

    Science.gov (United States)

    A healthy diet includes adding vegetables and fruit every day. Vegetables like broccoli, green beans, leafy greens, zucchini, cauliflower, cabbage, carrots, and tomatoes are low in calories and high in fiber, vitamins, and minerals. ...

  9. Vegetable Production System (Veggie)

    Data.gov (United States)

    National Aeronautics and Space Administration — The Vegetable Production System (Veggie) was developed to be a simple, easily stowed, high growth volume, low resource facility capable of producing fresh vegetables...

  10. Supercritical solvent extraction of oil sand bitumen

    Science.gov (United States)

    Imanbayev, Ye. I.; Ongarbayev, Ye. K.; Tileuberdi, Ye.; Mansurov, Z. A.; Golovko, A. K.; Rudyk, S.

    2017-08-01

    The supercritical solvent extraction of bitumen from oil sand studied with organic solvents. The experiments were performed in autoclave reactor at temperature above 255 °C and pressure 29 atm with stirring for 6 h. The reaction resulted in the formation of coke products with mineral part of oil sands. The remaining products separated into SARA fractions. The properties of the obtained products were studied. The supercritical solvent extraction significantly upgraded extracted natural bitumen.

  11. European Vegetation Archive (EVA)

    NARCIS (Netherlands)

    Chytrý, Milan; Hennekens, S.M.; Jiménez-Alfaro, Borja; Schaminée, J.H.J.; Haveman, Rense; Janssen, J.A.M.

    2016-01-01

    The European Vegetation Archive (EVA) is a centralized database of European vegetation plots developed by the IAVS Working Group European Vegetation Survey. It has been in development since 2012 and first made available for use in research projects in 2014. It stores copies of national and

  12. BETA DIVERSITY AND COMMUNITY DIFFERENTIATION IN DRY PERENNIAL SAND GRASSLANDS

    Directory of Open Access Journals (Sweden)

    E. KOVACS-LANG

    2011-01-01

    Full Text Available The spatial variability of species composition was studied in perennial sand grasslands in Hungary at multiple scales. Three sites were compared along an aridity gradient. Existing differences in climate along this ca. 200 km gradient correspond to regional climate changes predicted for the next 20-30 years. Six stands of Festucetum vaginatae grasslands were selected at each site within 400 x 1200 m areas for representing the coarse-scale within-site heterogeneity. Fine-scale compositional heterogeneity of vegetation within stands was sampled by recording the presence of species along 52 m long circular belt transects of 1040 units of 5 cm x 5 cm contiguous microquadrats. This sampling design enabled us to study the patterns of species combinations at a wide range of scales. The highest variability of plant species combinations appeared at very fine scales, between 10 cm and 25 cm. Differences in beta diversity along the gradient were scale-dependent. We found a decreasing trend of beta diversity with increasing aridity at fine scale, and on the contrary, an increasing trend at landscape scale. We conclude that the major trend of the vegetation differentiation due to aridity is the decrease of compositional variability at fine-scale accompanied by a coarse-scale diversification.

  13. Varying Inundation Regimes Differentially Affect Natural and Sand-Amended Marsh Sediments.

    Directory of Open Access Journals (Sweden)

    C Wigand

    Full Text Available Climate change is altering sea level rise rates and precipitation patterns worldwide. Coastal wetlands are vulnerable to these changes. System responses to stressors are important for resource managers and environmental stewards to understand in order to best manage them. Thin layer sand or sediment application to drowning and eroding marshes is one approach to build elevation and resilience. The above- and below-ground structure, soil carbon dioxide emissions, and pore water constituents in vegetated natural marsh sediments and sand-amended sediments were examined at varying inundation regimes between mean sea level and mean high water (0.82 m NAVD88 to 1.49 m NAVD88 in a field experiment at Laws Point, part of the Plum Island Sound Estuary (MA. Significantly lower salinities, pH, sulfides, phosphates, and ammonium were measured in the sand-amended sediments than in the natural sediments. In natural sediments there was a pattern of increasing salinity with increasing elevation while in the sand-amended sediments the trend was reversed, showing decreasing salinity with increasing elevation. Sulfide concentrations generally increased from low to high inundation with highest concentrations at the highest inundation (i.e., at the lowest elevations. High pore water phosphate concentrations were measured at low elevations in the natural sediments, but the sand-amended treatments had mostly low concentrations of phosphate and no consistent pattern with elevation. At the end of the experiment the lowest elevations generally had the highest measures of pore water ammonium. Soil carbon dioxide emissions were greatest in the sand-amended mesocosms and at higher elevations. Differences in coarse root and rhizome abundances and volumes among the sediment treatments were detected with CT imaging, but by 20 weeks the natural and sand-amended treatments showed similar total belowground biomass at the intermediate and high elevations. Although differences in

  14. Effect of manufactured sand on the durability characteristics of concrete

    Directory of Open Access Journals (Sweden)

    S. S. SARAVANAN

    2016-12-01

    Full Text Available Concrete is the most sought after material due to increase in construction activities and infrastructural developments. Availability of natural sand is decreasing thereby increase in the cost of construction. In the present work undertaken, an attempt has been made to give an alternative to natural sand. Optimization of replacement of natural sand with manufactured sand in concrete, durability studies such as water absorption, rapid chloride permeability test, sorptivity, acid resistance, alkaline resistance, impact resistance and abrasion resistance of M40 and M50 grades of concrete have been studied with manufactured sand as fine aggregate and compared the results with the conventional sand concrete. The results shows that there is an increase in the durability properties up to 70 % level of replacements of sand with manufactured sand as fine aggregate and for 100 % use of manufactured sand also gives the better durability than the conventional sand concrete.

  15. Studies on various characteristics of concrete structures using crushed sand

    International Nuclear Information System (INIS)

    Mimatsu, Makoto; Sugita, Hideaki; Yonemura, Masataka.

    1985-01-01

    With the recent advances of construction industry, the demands for concrete, hence for aggregate, are rising. The sand as such is in extreme shortage due to the exhaustion of river sand. Under the situation, the recent trends are for the use of crushed sand, i.e. the artificial sand obtained by crushing rocks, which have advantages of stabilized quality and adequate supplies. In building of nuclear power plants requiring large amounts of concrete, the usage of crushed sand is now unavoidable. The following are described : the situation of aggregate in Kyushu. production method of crushed sand and the quality standards, rocks used for crushed stone and sand and the properties, quality survey on crushed sand and the basic tests, characteristic tests of crushed-stone and -sand mixed concrete, the application of crushed sand in structures of the Sendai Nuclear Power Station. (Mori, K.)

  16. Provenance and recycling of Arabian desert sand

    Science.gov (United States)

    Garzanti, Eduardo; Vermeesch, Pieter; Andò, Sergio; Vezzoli, Giovanni; Valagussa, Manuel; Allen, Kate; Kadi, Khalid A.; Al-Juboury, Ali I. A.

    2013-05-01

    This study seeks to determine the ultimate origin of aeolian sand in Arabian deserts by high-resolution petrographic and heavy-mineral techniques combined with zircon U-Pb geochronology. Point-counting is used here as the sole method by which unbiased volume percentages of heavy minerals can be obtained. A comprehensive analysis of river and wadi sands from the Red Sea to the Bitlis-Zagros orogen allowed us to characterize all potential sediment sources, and thus to quantitatively constrain provenance of Arabian dune fields. Two main types of aeolian sand can be distinguished. Quartzose sands with very poor heavy-mineral suites including zircon occupy most of the region comprising the Great Nafud and Rub' al-Khali Sand Seas, and are largely recycled from thick Lower Palaeozoic quartzarenites with very minor first-cycle contributions from Precambrian basement, Mesozoic carbonate rocks, or Neogene basalts. Instead, carbonaticlastic sands with richer lithic and heavy-mineral populations characterize coastal dunes bordering the Arabian Gulf from the Jafurah Sand Sea of Saudi Arabia to the United Arab Emirates. The similarity with detritus carried by the axial Tigris-Euphrates system and by transverse rivers draining carbonate rocks of the Zagros indicates that Arabian coastal dunes largely consist of far-travelled sand, deposited on the exposed floor of the Gulf during Pleistocene lowstands and blown inland by dominant Shamal northerly winds. A dataset of detrital zircon U-Pb ages measured on twelve dune samples and two Lower Palaeozoic sandstones yielded fourteen identical age spectra. The age distributions all show a major Neoproterozoic peak corresponding to the Pan-African magmatic and tectonic events by which the Arabian Shield was assembled, with minor late Palaeoproterozoic and Neoarchean peaks. A similar U-Pb signature characterizes also Jafurah dune sands, suggesting that zircons are dominantly derived from interior Arabia, possibly deflated from the Wadi al

  17. Recovery of native prairie after pipeline construction in the Sand Hills region of Saskatchewan

    International Nuclear Information System (INIS)

    Walker, D.; Kremer, L.; Marshall, W.

    1996-01-01

    Land reclamation measures taken after construction of a large diameter natural gas pipeline in the Great Sand Hills region of southwestern Saskatchewan were detailed. Mitigation measures included modified construction procedures to minimize the size of the disturbance, worker educational programs to sensitize them to the prevailing fragile environment, dormant season construction, efforts to salvage topsoil seedbank, fertilizer application, straw bale wind barriers, brush mulch wind barriers, surface manipulation with the Hodder Gouger, fencing-out cattle, and the application of a seed mixture of agronomic legumes and native grasses. Vegetation and soil erosion were monitored over a period of four years. After four years the canopy cover was 88 per cent native species. On low-lying, protected sites vegetation was stable enough to support cattle grazing. Exposed sites will not reach this level of vegetation stability for some years to come due soil erosion by wind

  18. Reclamation research for the future at Syncrude Canada Ltd. : soil simulation-revegetation studies on tailings sand

    Energy Technology Data Exchange (ETDEWEB)

    Fedkenheuer, A W; Browne, J

    1979-12-01

    In response to the rising demand for energy in today's world, oil extracted from oil sands has become a viable energy source. Syncrude Canada Ltd. is a 2.2 billion dollar oil sands surface mining and processing venture situated in the Athabasca oil sands of northeastern Alberta. It is located near the town of Fort McMurray approximately 420 km north of Edmonton. During its planned 25 years of mine life, Syncrude expects to produce more than 1 billion barrels of oil from a 2800 ha mine area. Syncrude is committed to reclaiming this immense mine area. The reclamation objective is to return the disturbed site to a vegetative cover having a productivity which is equal to or greater than that which existed prior to disturbance. The reclaimed area must also be compatible with the neighboring natural areas. To accomplish this the vast quantities of tailings sand (that is, the leftover sand from which the oil has been extracted) must be reformed into a soil which is capable of supporting native plant communities. Researchers at Syncrude are looking for ways to use indigenous materials with the tailings sand to simulate a naturally-formed soil. Native plant species are being tested to see how well they will grow in such simulated soils and to evaluate their potential for use in large scale reclamation projects. This brochure describes the soil simulation-revegetation experiments going on at Syncrude.

  19. Nuclear energy in the oils sands

    International Nuclear Information System (INIS)

    Arsenault, J.E.

    2014-01-01

    The major Canadian oil sands are located in Alberta and Saskatchewan, with most production from the strata along the Athabasca River in Alberta. The economically recoverable oil sands reserves are estimated to be 168 billion barrels which at a current production rate of 1.8 million barrels per day (2012), are projected to last a very long time. Canada has been blessed with vast energy resources which make it potentially energy-independent and able to provide significant exports but there are concerns that their development cannot be managed in a wholly acceptable manner. Comparable concerns have been applied to nuclear energy in the past and in recent times to the oil sands. The technologies associated with these energy sources have always been controversial because they are at the confluence of economics and politics where finding a balance between risk and reward is difficult. So it should be no surprise that when these technologies get linked together in certain proposals their prospect for success is doubly difficult. The possible use of nuclear energy for production of oil from the oil sands dates back to the late 1950s, when an experiment to mine the oil by detonating an underground nuclear device was proposed. It was predicted that the heat and pressure released from such a device would create a large cavern into which oil would flow, and from where it would be pumped to the surface. Almost at the same time, oil sands research using conventional sources of energy had culminated with the development of practical refining processes, essentially those still in use today. These methods require large amounts of heat energy in the form of hot water and steam. In this century nuclear energy was proposed as the source for the heat required by the oil sands production processes. To date neither of these nuclear proposals for oil sands projects have been successful, because the economic and political balance could not be struck. (author)

  20. Nuclear energy in the oils sands

    Energy Technology Data Exchange (ETDEWEB)

    Arsenault, J.E.

    2014-09-15

    The major Canadian oil sands are located in Alberta and Saskatchewan, with most production from the strata along the Athabasca River in Alberta. The economically recoverable oil sands reserves are estimated to be 168 billion barrels which at a current production rate of 1.8 million barrels per day (2012), are projected to last a very long time. Canada has been blessed with vast energy resources which make it potentially energy-independent and able to provide significant exports but there are concerns that their development cannot be managed in a wholly acceptable manner. Comparable concerns have been applied to nuclear energy in the past and in recent times to the oil sands. The technologies associated with these energy sources have always been controversial because they are at the confluence of economics and politics where finding a balance between risk and reward is difficult. So it should be no surprise that when these technologies get linked together in certain proposals their prospect for success is doubly difficult. The possible use of nuclear energy for production of oil from the oil sands dates back to the late 1950s, when an experiment to mine the oil by detonating an underground nuclear device was proposed. It was predicted that the heat and pressure released from such a device would create a large cavern into which oil would flow, and from where it would be pumped to the surface. Almost at the same time, oil sands research using conventional sources of energy had culminated with the development of practical refining processes, essentially those still in use today. These methods require large amounts of heat energy in the form of hot water and steam. In this century nuclear energy was proposed as the source for the heat required by the oil sands production processes. To date neither of these nuclear proposals for oil sands projects have been successful, because the economic and political balance could not be struck. (author)

  1. Comparison between predicted and observed sand waves and sand banks in the North Sea

    NARCIS (Netherlands)

    Hulscher, Suzanne J.M.H.; van den Brink, G.M.

    2001-01-01

    For the first time a prediction model of regular morphological patterns on the seabed was tested against observations of sand wave and sand bank occurrence in the entire North Sea. The model, which originates from first physical principles, predicts this occurrence via two dimensionless parameters

  2. MORPHOMETRIC CHARACTERIZATION OF THE SAND FRACTION IN A SAND GRAIN IMAGE CAPTURE SYSTEM1

    Directory of Open Access Journals (Sweden)

    Lucimar Arruda Viana

    Full Text Available ABSTRACT Morphology studies assume significant importance in analysis of phenomena of granular systems packaging, in particular with a view to the use of the technique of soil stabilization named particle size correction in forest roads. In this context, this study aimed to develop and operationalize a Sand Grain Image Capture System and, hereby, determine the morphological indices of the sand fractions of two sandy soils called João Pinheiro (JP and Cachoeira da Prata (CP. Soil samples, air-dried, were sieved (2.0 mm nominal mesh size for removal of gravels. The materials that passed through the sieve were subjected to dispersion, washing in 0.053 mm nominal mesh size sieve, removal of organic matter and iron oxides to obtain the clean sand fractions. Subsequently, each soil sample was sieved for separation into twelve classes, between the diameters of 0.149 mm and 1.190 mm, using a Rotap shaker. Next, tests were carried out to characterize the morphometric attributes of the twelve classes of sand fractions of the soils studied. For validation of the performance of the Sand Grain Image Capture System, the results were compared to those obtained using a standard procedure for image analysis. The analysis of the results led to the following conclusions: (i the sand fraction of the JP soil presented higher values for the morphometric indices roundness, elongation and compactness compared to sand fraction of the CP soil; and (ii the Sand Grain Image Capture System worked properly, with practicality.

  3. Ecohydrology applications to ecosystem reconstruction after oil-sand mining

    Science.gov (United States)

    Mendoza, Carl; Devito, Kevin

    2014-05-01

    Oil-sand deposits in northeast Alberta, Canada comprise some of the world's largest oil reserves. Open-pit mining of these resources leads to waste-rock piles, tailings ponds and open pits that must be reclaimed to "equivalent landscape capability", with viable forests and wetlands, using only native vegetation. Understanding ecohydrological processes in natural systems is critical for designing the necessary landforms and landscapes. A challenge is the cold, sub-humid climate, with highly variable precipitation. Furthermore, there are competing demands, needs or uses for water, in both quantity and quality, for reclamation and sustainability of forestlands, wetlands and end-pit lakes. On average there is a potential water deficit in the region, yet wetlands cover half of the undisturbed environment. Water budget analyses demonstrate that, although somewhat unpredictable and uncontrollable, the magnitude and timing of water delivery largely control water storage and conservation within the landscape. The opportunity is to design and manipulate these reconstructed landscapes so that water is stored and conserved, and water quality is naturally managed. Heterogeneous geologic materials can be arranged and layered, and landforms sculpted, to minimize runoff, enhance infiltration, and promote surface and subsurface storage. Similarly, discharge of poor quality water can be minimized or focused. And, appropriate vegetation choices are necessary to conserve water on the landscape. To achieve these ends, careful attention must be paid to the entire water budget, the variability in its components, interconnections between hydrologic units, in both space and time, and coupled vegetation processes. To date our knowledge is guided primarily by natural analogues. To move forward, it is apparent that numerous priorities and constraints, which are potentially competing, must be addressed. These include geotechnical and operational requirements, material limitations or excesses

  4. Bacterial Rhizosphere Biodiversity from Several Pioneer Desert Sand Plants Near Jizan, Saudi Arabia

    KAUST Repository

    Osman, Jorge R.; Zelicourt, Axel de; Bisseling, Ton; Geurts, Rene; Hirt, Heribert; DuBow, Michael S.

    2016-01-01

    Life in arid regions and, in particular, hot deserts is often limited due to their harsh environmental conditions, such as large temperature fluctuations and low amounts of water. These extreme environments can influence the microbial community present on the surface sands and any rhizosphere members surrounding desert plant roots. The Jizan desert area, located in Saudi Arabia, supports particular vegetation that grows in the large sandy flat terrain. We examined five different samples, four from the rhizosphere of pioneer plants plus a surface sand sample, and used pyrosequencing of PCR-amplified V1-V3 regions of 16S rDNA genes from total extracted DNA to reveal and compare the bacterial population diversity of the samples. The results showed a total of 3,530 OTUs in the five samples, calculated using ≥ 97% sequence similarity levels. The Chao1 estimation of the bacterial diversity fluctuated from 637 to 2,026 OTUs for a given sample. The most abundant members found in the samples belong to the Bacteroidetes, Firmicutes and Proteobacteria phyla. This work shows that the Jizan desert area of Saudi Arabia can contain a diverse bacterial community on the sand and surrounding the roots of pioneer desert plants. It also shows that desert sand microbiomes can vary depending on conditions, with broad implications for sandstone monument bacterial communities

  5. Chronology and geochemistry of late Holocene eolian deposits in the Brandon Sand Hills, Manitoba, Canada

    Science.gov (United States)

    Wolfe, S.A.; Muhs, D.R.; David, P.P.; McGeehin, J.P.

    2000-01-01

    Accelerator mass spectrometry and conventional radiocarbon age determinations of organic matter from paleosols indicate that the Brandon Sand Hills area of southern Manitoba has been subjected to recurrent intervals of eolian activity in the past 5000 years. Although precise regional correlations are precluded by dating uncertainties, periods of most notable paleosol development occurred around 2300 to 2000, 1400 to 1000, and 600 to 500 cal yr BP with eolian activity occurring before and after each of these periods. Episodes of eolian activity may correspond to periods of regional drought, whereas paleosols mark periods of increased moisture availability and stabilization by vegetation. The geochemistry of the eolian sands, paleosols and source sediments indicates that partial leaching of carbonates occurs from pedogenesis during humid climatic phases, and that this is probably the primary mechanism of carbonate depletion of eolian sands in this area. Recent trends in sand dune activity from historic aerial photography and early explorers' accounts indicate that the few active dunes that presently exist have stabilized at a rate of 10-20% per decade, despite several severe droughts in the 20th century. This may be attributed to pre-settlement droughts that were more severe than those in historic times although regional dune stabilization may also be related, in part, to the spread of forest cover in the past few hundred years. Crown copyright (C) 2000 Published by Elsevier Science Ltd. All rights reserved.

  6. Bacterial Rhizosphere Biodiversity from Several Pioneer Desert Sand Plants Near Jizan, Saudi Arabia

    KAUST Repository

    Osman, Jorge R.

    2016-04-08

    Life in arid regions and, in particular, hot deserts is often limited due to their harsh environmental conditions, such as large temperature fluctuations and low amounts of water. These extreme environments can influence the microbial community present on the surface sands and any rhizosphere members surrounding desert plant roots. The Jizan desert area, located in Saudi Arabia, supports particular vegetation that grows in the large sandy flat terrain. We examined five different samples, four from the rhizosphere of pioneer plants plus a surface sand sample, and used pyrosequencing of PCR-amplified V1-V3 regions of 16S rDNA genes from total extracted DNA to reveal and compare the bacterial population diversity of the samples. The results showed a total of 3,530 OTUs in the five samples, calculated using ≥ 97% sequence similarity levels. The Chao1 estimation of the bacterial diversity fluctuated from 637 to 2,026 OTUs for a given sample. The most abundant members found in the samples belong to the Bacteroidetes, Firmicutes and Proteobacteria phyla. This work shows that the Jizan desert area of Saudi Arabia can contain a diverse bacterial community on the sand and surrounding the roots of pioneer desert plants. It also shows that desert sand microbiomes can vary depending on conditions, with broad implications for sandstone monument bacterial communities

  7. Heavy mineral concentration from oil sand tailings

    Energy Technology Data Exchange (ETDEWEB)

    Chachula, F.; Erasmus, N. [Titanium Corp. Inc., Regina, SK (Canada)

    2008-07-01

    This presentation described a unique technique to recover heavy minerals contained in the froth treatment tailings produced by oil sand mining extraction operations in Fort McMurray, Alberta. In an effort to process waste material into valuable products, Titanium Corporation is developing technology to recover heavy minerals, primarily zircon, and a portion of bitumen contained in the final stage of bitumen processing. The process technology is being developed to apply to all mined oil sands operations in the Fort McMurray region. In 2004, Titanium Corporation commissioned a pilot research facility at the Saskatchewan Research Council to test dry oil sands tailings. In 2005, a bulk sampling pilot plant was connected to the fresh oil sands tailings pipeline on-site in Fort McMurray, where washed sands containing heavy minerals were processed at a pilot facility. The mineral content in both deposited tailings and fresh pipeline tailings was assessed. Analysis of fresh tailings on a daily basis identified a constant proportion of zircon and higher levels of associated bitumen compared with the material in the deposited tailings. The process flow sheet design was then modified to remove bitumen from the heavy minerals and concentrate the minerals. A newly modified flotation process was shown to be a viable processing route to recover the heavy minerals from froth treatment tailings. 8 refs., 9 tabs., 12 figs.

  8. A Improved Seabed Surface Sand Sampling Device

    Science.gov (United States)

    Luo, X.

    2017-12-01

    In marine geology research it is necessary to obtain a suf fcient quantity of seabed surface samples, while also en- suring that the samples are in their original state. Currently,there are a number of seabed surface sampling devices available, but we fnd it is very diffcult to obtain sand samples using these devices, particularly when dealing with fne sand. Machine-controlled seabed surface sampling devices are also available, but generally unable to dive into deeper regions of water. To obtain larger quantities of seabed surface sand samples in their original states, many researchers have tried to improve upon sampling devices,but these efforts have generally produced ambiguous results, in our opinion.To resolve this issue, we have designed an improved andhighly effective seabed surface sand sampling device that incorporates the strengths of a variety of sampling devices. It is capable of diving into deepwater to obtain fne sand samples and is also suited for use in streams, rivers, lakes and seas with varying levels of depth (up to 100 m). This device can be used for geological mapping, underwater prospecting, geological engineering and ecological, environmental studies in both marine and terrestrial waters.

  9. Sand filter clogging by septic tank effluent.

    Science.gov (United States)

    Spychała, M; Błazejewski, R

    2003-01-01

    The aim of this study was to characterise conditions and factors affecting fine sand clogging by septic tank effluent on the basis of physical modelling. The physical model consisted of 12 sand columns dosed with sewage from one household (5 persons), preliminary treated in a septic tank. Hydraulic loadings of the sand filters were equal to 82 mm/d. The mean discharge from sand columns, measured as the effluent volume collected during 10 minutes, decreased significantly over the experiment period from 34 cm3/min in August 2000 to 20 cm3/min in August 2001 at the same temperature of about 20 degrees C. First the columns clogged almost completely after 480 days in December 2001, however six columns had remained unclogged till the end of the experiment (March 2002). The temperature had a significant impact on hydraulic conductivity. A vertical distribution of accumulated mass and biomass was investigated in partly clogged sand. Microscopic survey of the clogging layer showed a presence of live micro-organisms, residuals of dead micro-organisms, particularly pieces of small animal armour and many fibres. These particles accelerated the accumulation of solids in the upper clogging layer. The study indicated that temperature impact on the filter hydraulic conductivity was more significant for biological activity, than for sewage viscosity.

  10. The behavior of gaseous iodine in sand

    International Nuclear Information System (INIS)

    Takahashi, Kanji

    1974-01-01

    Radioactive iodine gas was passed through 10 different sands collected at rivers and hills. The relation between the amount of the loaded gas and the amount of adsorbed gas was determined at room temperature, 50 -- 60 0 C, and 90 -- 100 0 C under humidity of 2 sand. This amount was about 1 -- 3 times as much as that of monomolecular membrane adsorption, 0.2 -- 0.3 μg/cm 2 . The decrease of adsorption amount that accompanies the increase of humidity is attributable to the decrease of effective surface area of sand due to the presence of water. The transport of iodine in sand was studied by passing gaseous iodine through a glass tubing packed with sand. The distribution in the flow direction of iodine indicated that the ease of desorption depends upon the situation of adsorption. Easily desorbed case was named Henry type adsorption. Hardly desorbed case was named absorption type. Discussion is made on experimental results. (Fukutomi, T.)

  11. Mitigating in situ oil sands carbon costs

    Energy Technology Data Exchange (ETDEWEB)

    Theriault, D.J.; Peterson, J. [Laricina Energy Ltd., Calgary, AB (Canada); Heinrichs, H. [Canadian Chemical Technology Inc., Calgary, AB (Canada)

    2008-10-15

    Carbon capture and sequestration is a complex problem with a variety of dimensions that need to be considered. The political, social, and regulatory pressures are forcing carbon costs on the oil sands industry in an effort to reduce the carbon footprint of oil sands operations. This paper reviewed the political, social, and regulatory pressures and obligations for the in-situ oil sands industry. It presented the views and insights of Laricina Energy on the carbon challenge. It also described the initiatives that Laricina Energy is taking to manage these imperatives and outlined the challenges the industry is facing. The purpose of the paper was to encourage dialogue and collaboration by the oil sands industry. The paper also described the dimensions of the carbon problem and how the industry can contribute to a solution. Last, the paper reviewed the parameters of carbon dioxide or greenhouse gas containment and storage issues. It was concluded that the regulatory and policy requirements need to be clarified so that industry understands the new business landscape as well as the requirements that influence the economics of in-situ oil sands development. 7 refs., 7 figs.

  12. Carbon dioxide effluxes and their environmental controls in sagebrush steppe ecosystems along an elevation gradient in the Reynolds Creek Critical Zone Observatory

    Science.gov (United States)

    Lohse, K. A.; Fellows, A.; Flerchinger, G. N.; Seyfried, M. S.

    2017-12-01

    The spatial and temporal variation of carbon dioxide effluxes and their environmental controls are poorly constrained in cold shrub steppe ecosystems. The objectives of this study were to 1) analyze environmental parameters in determining soil CO2 efflux, 2) assess the level of agreement between manual chambers and force diffusion (FD) soil CO2 efflux chambers, when both measurements are extrapolated across the growing season, and lastly to compare respiration fluxes to modeled ecosystem respiration fluxes. We installed FD chambers at four sites co-located with eddy covariance (EC) towers and soil moisture and temperature sensors along an elevation gradient in the Reynolds Creek Critical Zone Observatory in SW Idaho. FD chamber fluxes were collected continuously at 15-minute intervals. We sampled soil CO2 efflux with manual chambers at plant and interplant spaces in five plots at each site biweekly to monthly during the growing season. The sites included a Wyoming big sagebrush site, a low sagebrush site, a post-fire mountain big sagebrush site, and a mountain big sagebrush site located at elevations of 1425, 1680, 1808 and 2111 m. Climate variation followed the montane elevation gradient; mean annual precipitation (MAP) at the sites is 290, 337, 425, and 795 mm, respectively, and mean annual temperature is 8.9, 8.4, 6.1, 5.4°C. Automated force diffusion chambers detected large differences in carbon dioxide pulse dynamics along the elevation gradient. Growing season carbon dioxide fluxes were 3 times higher at the 425 mm MAP site compared than the lowest elevation sites at 290 and 337 MAP sites and >1.5 higher than the 795 mm MAP site over the same period. Manual fluxes showed similar seasonal patterns as FD chamber fluxes but often higher and greater spatial variability in fluxes than FD chamber fluxes. Plant and interplant flux differences were surprisingly similar, especially at higher elevations. Soil respiration ranged from 0.2-0.48 of ecosystem respiration

  13. Sand transport, erosion and granular electrification

    DEFF Research Database (Denmark)

    Merrison, J.P.

    2012-01-01

    is expanding our current understanding and outline the areas of advancement needed in the future. Presentation is made of current models for wind driven detachment/entrainment and the transport rates of sand and dust, including the effects of contact induced grain electrification. This ubiquitous phenomenon...... can affect grain transport through the generation of intense electric fields and processes of electrostatic assembly. Importantly the transport of sand is characterized by saltation, which is known to be an active process for erosion and therefore a source for dust and sand formation. Using novel...... erosion simulation techniques the link between grain transport rates and erosion rates has been quantified. Furthermore this can be linked to production rates for dust and has been associated with chemical and mineral alteration through a process of mechanical activation of fractured surfaces. This work...

  14. Thermoluminescent dosimetric properties of Descalvado sand

    International Nuclear Information System (INIS)

    Teixeira, M.I.; Caldas, L.V.E.

    2006-01-01

    Sand samples proceeding from Descalvado, Sao Paulo, were studied with regard to their dosimetric properties using the thermoluminescence technique (TL) for high doses. These sand samples present steady physical and chemical characteristics to the end items, and they are used in the glass industry and for casting. The TL curves of the samples were obtained after an irradiation at the Gamma-Cell system ( 60 Co), of IPEN. The glow curves present two peaks at 80 C and 220 C approximately. Calibration curves were obtained for doses between 50 Gy and 5 kGy. The results indicate that the sand samples can be used for high-doses dosimetry in several areas of applications of ionizing radiation. (Author)

  15. Development tendencies of moulding and core sands

    Directory of Open Access Journals (Sweden)

    Stanislaw M. Dobosz1

    2011-11-01

    Full Text Available Further development of the technology for making moulding and core sands will be strictly limited by tough requirements due to protection of the natural environment. These tendencies are becoming more and more tense, so that we will reach a point when even processes, that from technological point of view fulfill high requirements of the foundry industry, must be replaced by more ecologically-friendly solutions. Hence, technologies using synthetic resins as binding materials will be limited. This paper presents some predictable development tendencies of moulding and core sands. The increasing role of inorganic substances will be noticed, including silicate binders with significantly improved properties, such as improved knock-out property or higher reclamation strength. Other interesting solutions might also be moulding sands bonded by geo-polymers and phosphate binders or salts and also binders based on degradable biopolymers. These tendencies and the usefulness of these binders are put forward in this paper.

  16. Thermoluminescent dosimetric properties of Descalvado sand

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, M.I.; Caldas, L.V.E

    2006-07-01

    Sand samples proceeding from Descalvado, Sao Paulo, were studied with regard to their dosimetric properties using the thermoluminescence technique (TL) for high doses. These sand samples present steady physical and chemical characteristics to the end items, and they are used in the glass industry and for casting. The TL curves of the samples were obtained after an irradiation at the Gamma-Cell system ({sup 60} Co), of IPEN. The glow curves present two peaks at 80 C and 220 C approximately. Calibration curves were obtained for doses between 50 Gy and 5 kGy. The results indicate that the sand samples can be used for high-doses dosimetry in several areas of applications of ionizing radiation. (Author)

  17. A Threshold Continuum for Aeolian Sand Transport

    Science.gov (United States)

    Swann, C.; Ewing, R. C.; Sherman, D. J.

    2015-12-01

    The threshold of motion for aeolian sand transport marks the initial entrainment of sand particles by the force of the wind. This is typically defined and modeled as a singular wind speed for a given grain size and is based on field and laboratory experimental data. However, the definition of threshold varies significantly between these empirical models, largely because the definition is based on visual-observations of initial grain movement. For example, in his seminal experiments, Bagnold defined threshold of motion when he observed that 100% of the bed was in motion. Others have used 50% and lesser values. Differences in threshold models, in turn, result is large errors in predicting the fluxes associated with sand and dust transport. Here we use a wind tunnel and novel sediment trap to capture the fractions of sand in creep, reptation and saltation at Earth and Mars pressures and show that the threshold of motion for aeolian sand transport is best defined as a continuum in which grains progress through stages defined by the proportion of grains in creep and saltation. We propose the use of scale dependent thresholds modeled by distinct probability distribution functions that differentiate the threshold based on micro to macro scale applications. For example, a geologic timescale application corresponds to a threshold when 100% of the bed in motion whereas a sub-second application corresponds to a threshold when a single particle is set in motion. We provide quantitative measurements (number and mode of particle movement) corresponding to visual observations, percent of bed in motion and degrees of transport intermittency for Earth and Mars. Understanding transport as a continuum provides a basis for revaluating sand transport thresholds on Earth, Mars and Titan.

  18. Gasification of oil sand coke: review

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E. [IMAF Group, Ottawa, ON (Canada)

    1998-08-01

    The production of synthetic crude from the tar sands in Western Canada has been steadily increasing. Most of the delayed coke produced by Suncor is combusted on site, whereas all fluid coke produced by Syncrude is stockpiled.The database on the chemical and physical properties of the oil sand coke, including the composition and fusion properties of the mineral matter, has been established. The reactivity of the coke was determined by oxygen chemisorption, fixed bed and fluid bed bench scale gasification and pilot plant gasification. The reactivity of the oil sand coke for gasification is rather low and comparable to high rank coals, such as anthracite. Slurrability tests revealed that a solid concentration in water, approaching 70 wt%, can be achieved. Gasification is the front runner among clean technologies for the conversion of carbonaceous solids to useful products. Several commercial gasifiers are available to cover the wide range of severity. Because of the low reactivity of oil sands coke, high severity conditions are required to achieve high gasification conversion. Such conditions can be attained in entrained bed gasifiers. Gasifiers employing both dry and slurry feeding systems are suitable. A high efficiency, low SO{sub x} and NO{sub x} emissions, as well as a low solid waste production are among the key advantages of the gasification technology compared with thecompeting technologies. Commercial gasification of oil sands coke is delayed because of the availability of natural gas on the site of the upgrading plants. Potential for the transportation of the oil sand coke to USA for electricity generation using the integrated gasification combined-cycle (IGCC) technology was evaluated. 27 refs., 17 figs., 9 tabs.

  19. Contemporary sand wedge development in seasonally frozen ground and paleoenvironmental implications

    Science.gov (United States)

    Wolfe, Stephen A.; Morse, Peter D.; Neudorf, Christina M.; Kokelj, Steven V.; Lian, Olav B.; O'Neill, H. Brendan

    2018-05-01

    Contemporary sand wedges and sand veins are active in seasonally frozen ground within the extensive discontinuous permafrost zone in Northwest Territories, Canada. The region has a subarctic continental climate with 291 mm a-1 precipitation, -4.1 °C mean annual air temperature, warm summers (July mean 17.0 °C), and cold winters (January mean -26.6 °C). Five years of continuous observations indicate that interannual variation of the ground thermal regime is dominantly controlled by winter air temperature and snow cover conditions. At sandy sites, thin snow cover and high thermal conductivity promote rapid freezing, high rates of ground cooling, and low near-surface ground temperatures (-15 to -25 °C), resulting in thermal contraction cracking to depths of 1.2 m. Cracking potentials are high in sandy soils when air temperatures are air temperatures are ≤-17 °C, and snow cover is conditions in peatlands maintain permafrost, but thermal contraction cracking does not occur because thicker snow cover and the thermal properties of peat prolong freezeback and maintain higher winter ground temperatures. A combination of radiocarbon dating, optical dating, and stratigraphic observations were used to differentiate sand wedge types and formation histories. Thermal contraction cracks that develop in the sandy terrain are filled by surface (allochthonous) and/or host (autochthonous) material during the thaw season. Epigenetic sand wedges infilled with allochthonous sand develop within former beach sediments beneath an active eolian sand sheet. Narrower and deeper syngenetic wedges developed within aggrading eolian sand sheets, whereas wider and shallower antisyngenetic wedges developed in areas of active erosion. Thermal contraction cracking beneath vegetation-stabilized surfaces leads to crack infilling by autochthonous host and overlying organic material, with resultant downturning and subsidence of adjacent strata. Sand wedge development in seasonally frozen ground

  20. On the Size Distribution of Sand

    DEFF Research Database (Denmark)

    Sørensen, Michael

    2016-01-01

    A model is presented of the development of the size distribution of sand while it is transported from a source to a deposit. The model provides a possible explanation of the log-hyperbolic shape that is frequently found in unimodal grain size distributions in natural sand deposits, as pointed out......-distribution, by taking into account that individual grains do not have the same travel time from the source to the deposit. The travel time is assumed to be random so that the wear on the individual grains vary randomly. The model provides an interpretation of the parameters of the NIG-distribution, and relates the mean...

  1. Creating fluid injectivity in tar sands formations

    Science.gov (United States)

    Stegemeier, George Leo; Beer, Gary Lee; Zhang, Etuan

    2010-06-08

    Methods for treating a tar sands formation are described herein. Methods for treating a tar sands may include heating a portion of a hydrocarbon layer in the formation from one or more heaters located in the portion. The heat may be controlled to increase the permeability of at least part of the portion to create an injection zone in the portion with an average permeability sufficient to allow injection of a fluid through the injection zone. A drive fluid and/or an oxidizing fluid may be provided into the injection zone. At least some hydrocarbons are produced from the portion.

  2. Log-inject-log in sand consolidation

    International Nuclear Information System (INIS)

    Murphy, R.P.; Spurlock, J.W.

    1977-01-01

    A method is described for gathering information for the determination of the adequacy of placement of sand consolidating plastic for sand control in oil and gas wells. The method uses a high neutron cross-section tracer which becomes part of the plastic and uses pulsed neutron logging before and after injection of the plastic. Preferably, the method uses lithium, boron, indium, and/or cadmium tracers. Boron oxide is especially useful and can be dissolved in alcohol and mixed with the plastic ingredients

  3. Oil sand synfuel production using nuclear energy

    International Nuclear Information System (INIS)

    Barnert, H.

    1984-10-01

    The importance of oil sand as a primary energy carrier is illustrated. The oil sand mining project 'synfuel' in Fort McMurray, Alberta, Canada, is described. On the basis of a layout of an In-situ-process different possibilities of introducing nuclear energy to the process are described. This leads to an increase of the product yield, leading finally to a doubling of the energy output compared to the reference layout. The introduction of nuclear energy contributes to the reduction of emissions, in particular to the emission of carbon dioxide in the conversion process. (orig.)

  4. Permeability Tests on Silkeborg Sand No. 0000

    DEFF Research Database (Denmark)

    Lund, Willy; Jakobsen, Kim Parsberg

    on the characteristics of the soil matrix, the permeability is determined for different void ratios. All tests are performed on reconstituted specimens of Silkeborg Sand No. 0000. The permeability is determined by use of a falling head apparatus. The apparatus, test procedures and the analysis method are described......The flow through porous media plays an important role in various engineering disciplines, as for example in ground water hydrology and soil mechanics. In the present study the permeability is determined for a fine, saturated sand. As the flow through a porous media strongly depends...

  5. Permeability Tests on Eastern Scheldt Sand

    DEFF Research Database (Denmark)

    Jakobsen, Kim Parsberg

    on the characteristics of the soil matrix, the permeability is determined for different void ratios. All tests are performed on reconstituted specimens of Eastern Scheldt Sand. The permeability is determined by use of a falling head apparatus. Finally the test results are briefly summarised and a relationship between......The flow through porous media plays an important role in various engineering disciplines, as for example in ground water hydrology and soil mechanics. In the present study the permeability is determined for a fine, saturated sand. As the flow through a porous media strongly depends...

  6. Sand control systems used in completing wells

    Directory of Open Access Journals (Sweden)

    Gabriel Wittenberger

    2005-12-01

    Full Text Available Expandable Tubular Technology is transforming the face of well completion and construction. This technology provides: a substantially higher hydrocarbon production rates from the reservoir, a reduced well drilling and construction costs, new possibilities for previously unreachable or uneconomic reservoirs, and step a change towards the single diameter well. ESS (Expandable Sand Screen has an unrivalled performance worldwide for delivering a reliable sand control in a wide range of applications. Well costs typically cut by over 20 %, and the productivity increases up to 70 %.

  7. Irradiation of dehydrated vegetables

    International Nuclear Information System (INIS)

    Esterhuyse, A; Esterhuizen, T.

    1985-01-01

    The reason for radurization was to decreased the microbial count of dehydrated vegetables. The average absorbed irradiation dose range between 2kGy and 15kGy. The product catagories include a) Green vegetables b) White vegetables c) Powders of a) and b). The microbiological aspects were: Declining curves for the different products of T.P.C., Coliforms, E. Coli, Stap. areus, Yeast + Mold at different doses. The organoleptical aspects were: change in taste, flavour, texture, colour and moisture. The aim is the marketing of irradiated dehydrated vegetables national and international basis

  8. Experimental perforation of tubing with a hydraulic sand jet

    Energy Technology Data Exchange (ETDEWEB)

    Semenov, Yu V

    1970-01-01

    A series of field tests has shown that perforation with a hydraulic sand jet improves the quality of well completion. The sand jet does not crack the cement sheath or the casing, and the perforations are larger and deeper than perforations formed by explosive charges. Fluid circulation during sand jet perforation can safely be stopped for at least 10 min. Water containing a surfactant can be used as a sand carrier. Sand jet perforation allows successful completion of wells cased by 2 tubing strings. Sand jet perforation can be used to clean the borehole well and to remove foreign objects from the well.

  9. Land Sensitivity Analysis of Degradation using MEDALUS model: Case Study of Deliblato Sands, Serbia

    Directory of Open Access Journals (Sweden)

    Kadović Ratko

    2016-12-01

    Full Text Available This paper studies the assessment of sensitivity to land degradation of Deliblato sands (the northern part of Serbia, as a special nature reserve. Sandy soils of Deliblato sands are highly sensitive to degradation (given their fragility, while the system of land use is regulated according to the law, consisting of three zones under protection. Based on the MEDALUS approach and the characteristics of the study area, four main factors were considered for evaluation: soil, climate, vegetation and management. Several indicators affecting the quality of each factor were identified. Each indicator was quantified according to its quality and given a weighting of between 1.0 and 2.0. ArcGIS 9 was utilized to analyze and prepare the layers of quality maps, using the geometric mean to integrate the individual indicator map. In turn, the geometric mean of all four quality indices was used to generate sensitivity of land degradation status map. Results showed that 56.26% of the area is classified as critical; 43.18% as fragile; 0.55% as potentially affected and 0.01% as not affected by degradation. The values of vegetation quality index, expressed as coverage, diversity of vegetation functions and management policy during the protection regime are clearly represented through correlation coefficient (0.87 and 0.47.

  10. A flora melitófila de uma área de dunas com vegetação de caatinga, Estado da Bahia, Nordeste do Brasil The bee flora of caatinga vegetation on sand dunes in Bahia State, Northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Ana Tereza Araújo Rodarte

    2008-06-01

    manutenção das abelhas solitárias, de pequeno porte, incapazes de competir eficientemente com abelhas eussociais com alta capacidade de comunicação e exploração dos recursos mais abundantes como Apis mellifera. Os resultados indicaram que não apenas a composição florística, mas a estratificação e a forte sazonalidade da floração foram determinantes da composição e do padrão local de uso de recursos pelas abelhas em caatinga.The plant species in an area of caatinga vegetation (10º47'37'S and 42º49'25'W were surveyed to identify flower morphology, available floral resources, flowering characteristics, and visiting bee species. Collections were made for four consecutive days in February, April, June, August, and December/2000. The area was surveyed between 06:00 and 17:00 h by following two parallel transects (450 m × 100 m and 550 m × 100 m, 50 m apart (total of 10 hectares. The 42 plant identified (55% of the local flora were visited by a total of 2924 bees belonging to 41 species. The plant families Caesalpiniaceae and Malpighiaceae were the most frequently visited. The plant species most often visited by 35 species of bees (78% of the total number of bees surveyed were: Byrsonima blanchetiana Miq., Copaifera coriacea Mart., Senna macranthera, Peltogyne pauciflora Benth., Senna gardneri (Benth. H.S. Irwin & Barneby, Serjania comata, Mouriri pusa (Gardner, Jatropha mutabilis (Pohl. Baill., Maytenus rigida Mart. and Turnera calyptrocarpa Urb. (24% of the total bee flora. These plant species were responsible for 95% of total flower production during the study period. Generally, the basic floral morphology of these species consisted of small, white to pink, zygomorphic flowers displayed in inflorescences, monoclinous, with longitudinal anthers dehiscence; this morphology was very similar to that of the flora, suited to generalist pollinators. The predominance of generalist interactions reflects the local abundance of stingless bees (Meliponinae and Apis

  11. Effects of projected climate change on vegetation in the Blue Mountains ecoregion, USA

    Directory of Open Access Journals (Sweden)

    Becky K. Kerns

    2018-04-01

    Full Text Available We used autecological, paleoecological, and modeling information to explore the potential effects of climate change on vegetation in the Blue Mountains ecoregion, Oregon (USA. Although uncertainty exists about the exact nature of future vegetation change, we infer that the following are likely to occur by the end of the century: (1 dominance of ponderosa pine and sagebrush will increase in many locations, (2 the forest-steppe ecotone will move upward in latitude and elevation, (3 ponderosa pine will be distributed at higher elevations, (4 subalpine and alpine systems will be replaced by grass species, pine, and Douglas-fir, (5 moist forest types may increase under wetter scenarios, (6 the distribution and abundance of juniper woodlands may decrease if the frequency and extent of wildfire increase, and (7 grasslands and shrublands will increase at lower elevations. Tree growth in energy-limited landscapes (high elevations, north aspects will increase as the climate warms and snowpack decreases, whereas tree growth in water-limited landscapes (low elevations, south aspects will decrease. Ecological disturbances, including wildfire, insect outbreaks, and non-native species, which are expected to increase in a warmer climate, will affect species distribution, tree age, and vegetation structure, facilitating transitions to new combinations of species and vegetation patterns. In dry forests where fire has not occurred for several decades, crown fires may result in high tree mortality, and the interaction of multiple disturbances and stressors will probably exacerbate stress complexes. Increased disturbance will favor species with physiological and phenological traits that allow them to tolerate frequent disturbance. Keywords: Climate change, Disturbance, Vegetation, Wildfire

  12. Hydroponic production of Chinese water chestnut corms for potential use as a functional vegetable

    Science.gov (United States)

    Chinese water chestnut is used as a canned or raw vegetable worldwide. The accessions in the USDA, ARS, Plant Genetic Resources Conservation Unit do not produce very many or healthy corms when grown in plastic pots containing flooded sand in Griffin, GA. This study was conducted to use a drip irriga...

  13. MouldingSandDB – a modern database storing moulding sands properties research results

    Directory of Open Access Journals (Sweden)

    J. Jakubski

    2011-01-01

    Full Text Available The complexity of foundry processes requires the use of modern, advanced IT tools for optimization, storage and analysis of t echnicaldata. Properties of moulding and core sands that are collected in research laboratories, manufacturers, and finally in the foundries, are not in use later on. It seems important to create a database that will allow to use the results stored, along with the possibility of searching according to set criteria, adjusted to casting practice. This paper presents part of the database named „MouldingSandDB”, which allows to collect and search data for synthetic moulding sands.

  14. Undrained Cyclic Behaviour of Dense Frederikshavn Sand

    DEFF Research Database (Denmark)

    Nielsen, Søren Kjær; Ibsen, Lars Bo; Sørensen, Kris Wessel

    2013-01-01

    A modified contour diagram is created for the Frederikshavn Sand in the undrained case for a relative density of ID = 80 %. It can be used to estimate the number of cycles to failure for a given combination of pore pressure, average and cyclic load ratio. The diagram is based on a series of undra...

  15. Radiation safety in Australia's mineral sands industry

    International Nuclear Information System (INIS)

    Hughes, W.

    1989-06-01

    This brochure is part of a training package aiming to explain in simple terms what radiation is, how it affects people's lives and how, in the specific case of the mineral sand industry, the risk of ill-effects from low-level radioactivity could be effectively guarded against by simple and easily followed safety precautions. ills

  16. Geomechanical properties of lime stabilized clayey sands

    International Nuclear Information System (INIS)

    Arabani, M.; Karami, M. Veis

    2007-01-01

    Clayey sands that have low plasticity, low compressibility and high strength under loads, are suitable as a base material for any engineering construction projects as well as for roads and building construction. Decrease of plasticity and compressibility as well as increase in strength of these materials can be obtained by many different methods. Of these methods, lime stabilization is a common, applicable, and easy to use approach that can improve geomechanical and geotechnical properties of clayey sand fills. In this study some important geomechanical properties and geotechnical properties of clayey sands including compressive strength, CBR and elastic plastic behavior are investigated. A range of gradations representative of those gradations found in situ in the north of Iran were selected for testing and samples were artificially rebuilt in the laboratory. The mixes were then stabilized with hydrated lime and cured. Different mechanical tests were performed on mature materials. The stress-strain behavior of lime-stabilized mixes was plotted and a parabolic function was used to estimate the trend of stress-strain behavior. The data show that there is a correlation among the results of uniaxial load test, tensile strength, and CBR of the tested specimens. Also, results of the unconfined compression test and the indirect tensile strength test show that an increase in clay content up to a certain percent, in the clay-sand fills, tends to increase the strength of the materials in compression as well as in tension. (author)

  17. Market opportunities and challenges for oil sands

    International Nuclear Information System (INIS)

    Wise, T.H.

    2004-01-01

    The use of Alberta bitumen as a clean fuel depends on upgrading, transportation, and refining processes. Forecasts show that oil sands production, which includes synthetic crude oil (SCO), will surpass declining conventional production from the Western Canada Sedimentary Basin. The challenges facing the oils sands processing industry include: crude oil prices which affect the producer's market; market expansion options; diluent availability/cost; supply cost competitiveness; and, regional processing. The common market issues include light/heavy crude prices, oil sands crude qualities, prices of oil sands crudes, pipeline infrastructure, and competitive supplies. The issues facing the refiners are: refining margins, security of crude supply, refined product quality, and competitive product supply. It was noted that Alberta must retain or increase its share of the Midwest market. The market expansion options were reviewed for both downstream (refining) and upstream (upgrading) operations. New pipeline capacity is needed to reach more distant markets such as Southern Midwest, Washington, and California. The market is nearly saturated for Canada's heavy oil supply. More upgrading will be required as bitumen production increases. Market growth is still possible for Canada's SCO but according to forecasts, the market could also become saturated. To increase demand and allow supplies to grow, SCO prices may fall below light crude prices. It was noted that a balance must be achieved in order for producers to increase production and for refiner/upgraders to expand their conversion capacity. 13 figs

  18. Growing markets to sustain oil sands development

    International Nuclear Information System (INIS)

    Wise, T.H.

    2003-01-01

    The utilization of Alberta bitumen for the clean fuels market depends on upgrading, transportation, and refining processes. Forecasts show that oil sands production, which includes synthetic crude oil (SCO), will surpass declining conventional production in Western Canada. Several issues pose a challenge to the oil sands processing industry. The producers' market is affected by crude oil prices, market expansion options, diluent availability/cost, supply cost competitiveness, and regional processing. The common market issues include light/heavy crude prices, oil sands crude qualities, prices of oil sands crudes, pipeline infrastructure, and competitive supplies. The issues facing the refiners are: refining margins, security of crude supply, refined product quality, and competitive product supply. A brief review of markets for Canadian crude oil, including synthetic crude, was provided. The share of the Midwest market by Alberta must be retained and increased. The market expansion options were reviewed for both downstream (refining) and upstream (upgrading) operations. To reach more distant markets such as Southern Midwest, Washington, and California, new pipeline capacity would be required. The market is nearly saturated for Canada's heavy oil supply. More upgrading will be required as bitumen production increases. Market growth is still possible for Canada's SCO but according to forecasts, the market could also become saturated. To increase demand and allow supplies to grow, SCO prices may fall below light crude prices. It was noted that a balance must be achieved in order for producers to increase production and for refiner/upgraders to expand their conversion capacity. tabs., figs

  19. Microbial Characterization of Qatari Barchan Sand Dunes.

    Directory of Open Access Journals (Sweden)

    Sara Abdul Majid

    Full Text Available This study represents the first characterization of sand microbiota in migrating barchan sand dunes. Bacterial communities were studied through direct counts and cultivation, as well as 16S rRNA gene and metagenomic sequence analysis to gain an understanding of microbial abundance, diversity, and potential metabolic capabilities. Direct on-grain cell counts gave an average of 5.3 ± 0.4 x 105 cells g-1 of sand. Cultured isolates (N = 64 selected for 16S rRNA gene sequencing belonged to the phyla Actinobacteria (58%, Firmicutes (27% and Proteobacteria (15%. Deep-sequencing of 16S rRNA gene amplicons from 18 dunes demonstrated a high relative abundance of Proteobacteria, particularly enteric bacteria, and a dune-specific-pattern of bacterial community composition that correlated with dune size. Shotgun metagenome sequences of two representative dunes were analyzed and found to have similar relative bacterial abundance, though the relative abundances of eukaryotic, viral and enterobacterial sequences were greater in sand from the dune closer to a camel-pen. Functional analysis revealed patterns similar to those observed in desert soils; however, the increased relative abundance of genes encoding sporulation and dormancy are consistent with the dune microbiome being well-adapted to the exceptionally hyper-arid Qatari desert.

  20. Afyon-Sandıklı

    Indian Academy of Sciences (India)

    δ18O and δD isotope ratios of the Sandıklı waters plot along the continental meteoric water line ... and district heating. Several studies on geology, hydrogeology along ..... precipitation; In: Handbook of Environmental Isotope. Geochemistry ...

  1. Dark grains of sand: a geological storytelling

    Science.gov (United States)

    Gallo Maresca, Magda

    2017-04-01

    In the secondary Italian school the Earth science learning begins at first year, in synergy with other natural science subjects such as Astronomy, Chemistry and Biology. Italian teachers have to focus on the landscape geomorphological aspects and often Earth processes are difficult to display since they are related to certain phenomena happened during the past and often far from the involved country. In order to better understand the environment surrounding us, very simple and poor materials, like sands, allow the teachers to create attractive lab experiences. According to the IBSE (Inquiry Based Science Education) approach, a learning unit has been implemented starting from a walking along the light carbonate beaches of the Adriatic sea: a smart look to the sands ("engage step"), stroke the students fantasy pushing them to explore some strange black grains on the sands. Dirty sands? Or rock landscape, soil degradation and Ofanto river and coastal processes (erosion, transportation and deposition)? This was the teaching challenge. Due to the youngest age, a third level, guided inquiry, was adopted so the teacher is the "guide of inquiry" encouraging the students using the research question ("Why is the sand dark?", "Do all sands look the same?", "Where does it come from?") and driving the students around their investigation plans ("How can I measure grain size?"). A procedure to answer the above questions and validate the results and explanations has been implemented to allow the students to be proactive in their study. During the learning activities will be the students to ask for field trip to elaborate their new knowledge, verify and visualize the speculated processes. The teaching skills allow to address several geosciences domains such as mineralogy, petrology, regional geology and geodynamics as well as other scientific disciplines such as mathematics (more specifically statistics), forensic science and even life sciences (the presence of bioclasts might

  2. The provenance of Taklamakan desert sand

    Science.gov (United States)

    Rittner, Martin; Vermeesch, Pieter; Carter, Andrew; Bird, Anna; Stevens, Thomas; Garzanti, Eduardo; Andò, Sergio; Vezzoli, Giovanni; Dutt, Ripul; Xu, Zhiwei; Lu, Huayu

    2016-03-01

    Sand migration in the vast Taklamakan desert within the Tarim Basin (Xinjiang Uyghur Autonomous region, PR China) is governed by two competing transport agents: wind and water, which work in diametrically opposed directions. Net aeolian transport is from northeast to south, while fluvial transport occurs from the south to the north and then west to east at the northern rim, due to a gradual northward slope of the underlying topography. We here present the first comprehensive provenance study of Taklamakan desert sand with the aim to characterise the interplay of these two transport mechanisms and their roles in the formation of the sand sea, and to consider the potential of the Tarim Basin as a contributing source to the Chinese Loess Plateau (CLP). Our dataset comprises 39 aeolian and fluvial samples, which were characterised by detrital-zircon U-Pb geochronology, heavy-mineral, and bulk-petrography analyses. Although the inter-sample differences of all three datasets are subtle, a multivariate statistical analysis using multidimensional scaling (MDS) clearly shows that Tarim desert sand is most similar in composition to rivers draining the Kunlun Shan (south) and the Pamirs (west), and is distinctly different from sediment sources in the Tian Shan (north). A small set of samples from the Junggar Basin (north of the Tian Shan) yields different detrital compositions and age spectra than anywhere in the Tarim Basin, indicating that aeolian sediment exchange between the two basins is minimal. Although river transport dominates delivery of sand into the Tarim Basin, wind remobilises and reworks the sediment in the central sand sea. Characteristic signatures of main rivers can be traced from entrance into the basin to the terminus of the Tarim River, and those crossing the desert from the south to north can seasonally bypass sediment through the sand sea. Smaller ephemeral rivers from the Kunlun Shan end in the desert and discharge their sediment there. Both river run

  3. Balkan Vegetation Database

    NARCIS (Netherlands)

    Vassilev, Kiril; Pedashenko, Hristo; Alexandrova, Alexandra; Tashev, Alexandar; Ganeva, Anna; Gavrilova, Anna; Gradevska, Asya; Assenov, Assen; Vitkova, Antonina; Grigorov, Borislav; Gussev, Chavdar; Filipova, Eva; Aneva, Ina; Knollová, Ilona; Nikolov, Ivaylo; Georgiev, Georgi; Gogushev, Georgi; Tinchev, Georgi; Pachedjieva, Kalina; Koev, Koycho; Lyubenova, Mariyana; Dimitrov, Marius; Apostolova-Stoyanova, Nadezhda; Velev, Nikolay; Zhelev, Petar; Glogov, Plamen; Natcheva, Rayna; Tzonev, Rossen; Boch, Steffen; Hennekens, Stephan M.; Georgiev, Stoyan; Stoyanov, Stoyan; Karakiev, Todor; Kalníková, Veronika; Shivarov, Veselin; Russakova, Veska; Vulchev, Vladimir

    2016-01-01

    The Balkan Vegetation Database (BVD; GIVD ID: EU-00-019; http://www.givd.info/ID/EU-00- 019) is a regional database that consists of phytosociological relevés from different vegetation types from six countries on the Balkan Peninsula (Albania, Bosnia and Herzegovina, Bulgaria, Kosovo, Montenegro

  4. Soil and vegetation surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, E.J.

    1995-06-01

    Soil sampling and analysis evaluates long-term contamination trends and monitors environmental radionuclide inventories. This section of the 1994 Hanford Site Environmental Report summarizes the soil and vegetation surveillance programs which were conducted during 1994. Vegetation surveillance is conducted offsite to monitor atmospheric deposition of radioactive materials in areas not under cultivation and onsite at locations adjacent to potential sources of radioactivity.

  5. High temperature thermal energy storage in moving sand

    Science.gov (United States)

    Turner, R. H.; Awaya, H. I.

    1978-01-01

    Several high-temperature (to 500 C) heat-storage systems using sand as the storage medium are described. The advantages of sand as a storage medium include low cost for sand, widespread availability, non-toxicity, non-degradation characteristics, easy containment, and safety. The systems considered include: stationary sand with closely spaced tubes throughout the volume, the use of a fluidized bed, use of conveyor belt transporter, and the use of a blower rapid transport system. For a stationary sand bed, very close spacing of heat transfer tubes throughout the volume is required, manifesting as high power related system cost. The suggestion of moving sand past or around pipes is intended to reduce the power related costs at the penalty of added system complexity. Preliminary system cost estimates are offered. These rough calculations indicate that mobile sand heat storage systems cost less than the stationary sand approach.

  6. Characteristics of SCC with Fly Ash and Manufactured Sand

    Science.gov (United States)

    Praveen Kumar, K.; Radhakrishna

    2016-09-01

    Self compacting concrete (SCC) of M40 grade was designed. The binder in SCC consists of OPC and fly ash in the ratio of 65:35. River sand was replaced by manufactured sand (M-sand) at replacement levels of 20,40,60,80 and 100%. An attempt was made to evaluate the workability and strength characteristics of self compacting concrete with river sand and manufactured sand as fine aggregates. For each replacement level, constant workability was maintained by varying the dosage of superplasticizer. T50 flow time, V Funnel time, V-funnel T5 time as well as compressive, split tensile and flexural strength of SCC were found at each replacement level of M-sand. They were compared to SCC with river sand. Results indicate favourable use of M-sand in preparation of Self Compacting Concrete.

  7. Field test on sand compaction pile method with copper slag sand; Dosuisai slag wo mochiita SCP koho no shiken seko

    Energy Technology Data Exchange (ETDEWEB)

    Minami, K.; Matsui, H.; Naruse, E.; Kitazume, M. [Port and Harbour Research Inst., Kanagawa (Japan)

    1997-09-20

    This paper describes the sand compaction pile (SCP) method using copper slag sand. The SCP method is a method by which sand compaction piles are constructed in the ground, and improvement can be obtained in a short period. This method has been widely used even in the port areas for enhancing the bearing power of soft clay ground and the lateral resistance of sheet pile. A great deal of sand is required as a material. The sand requires high permeability, proper size distribution with less fine particle fraction content, easy compaction property with enough strength, and easy discharging property from the casing of construction machines as required properties. Recently, it becomes hard to secure proper sand materials. The copper slag sand is obtained from refining process of copper as a by-product which is quenched in water flow and crushed in water. The copper slag sand has higher particle density than that of sand, excellent permeability, and similar size distribution to that of sand. From compaction drainage triaxial compression test and permeability test, it was found that the mechanical properties of copper slag sand did not change by the crushing of grains with keeping excellent permeability. Through the test construction, applicability of the copper slag sand to the SCP method could be confirmed as an alternate material of sand. 17 refs., 9 figs., 4 tabs.

  8. Method of producing vegetable puree

    DEFF Research Database (Denmark)

    2004-01-01

    A process for producing a vegetable puree, comprising the sequential steps of: a)crushing, chopping or slicing the vegetable into pieces of 1 to 30 mm; b) blanching the vegetable pieces at a temperature of 60 to 90°C; c) contacted the blanched vegetable pieces with a macerating enzyme activity; d......) blending the macerated vegetable pieces and obtaining a puree....

  9. Vegetation survey: a new focus for Applied Vegetation Science

    NARCIS (Netherlands)

    Chytry, M.; Schaminee, J.H.J.; Schwabe, A.

    2011-01-01

    Vegetation survey is an important research agenda in vegetation science. It defines vegetation types and helps understand differences among them, which is essential for both basic ecological research and applications in biodiversity conservation and environmental monitoring. In this editorial, we

  10. Southeast Florida Sediment Assessment and Needs Determination (SAND) Study

    Science.gov (United States)

    2014-09-01

    sand with some shell beds, sandstone , and limestone *Miami Limestone 0 to 80 ft Oolitic limestone, quartz sand, and sandstone Anastasia 0 to 100 ft...Sand, shell beds, marl, calcareous sandstone (coquina/calcarenite) Fort Thompson 0 to 80 ft Silty limestone, silty sand, clayey marl, shell marl...highly- to moderately- weathered quartzose sandstone , and highly-weathered (saprolitic) to moderately-weathered hard limestone. North-south and

  11. Biodegradable materials as binders for IVth generation moulding sands

    OpenAIRE

    K. Major-Gabry

    2015-01-01

    This paper focuses on the possibility of using the biodegradable materials as binders (or parts of binders?compositions) for foundry moulding and core sands. Results showed that there is a great possibility of using available biodegradable materials as foundry moulding sand binders. Using biodegradable materials as partial content of new binders, or additives to moulding sands may not only decrease the toxicity and increase reclamation ability of tested moulding sands, but also accelerate the...

  12. SPECIFIC RESISTANCE AND SPECIFIC INTENSITY OF BELT SANDING OF WOOD

    Directory of Open Access Journals (Sweden)

    Boleslaw Porankiewicz

    2010-06-01

    Full Text Available This paper examines and discusses the specific belt sanding resistance K (N·cm-2 and specific belt sanding intensity SI (g·cm-2·min-1, for wood of Pinus sylvestris L., Picea abies L., Quercus robra L., Acer pseudoplatanus L., Alnus glutinosa Gaertn., and Populus Nigra L., by different sanding pressure pS, different sanding grit NG number, and different wood grain angles Phi(v.

  13. Quality stabilisation of synthetic sand containing bentonite in process lines

    OpenAIRE

    A. Fedoryszyn

    2010-01-01

    Stabilisation of sand quality requires the monitoring and control of sand moisture contents and its other parameters at each stage of sandprocessing, i.e. during the preparation of return sand mix and rebonding processes. Stabilisation of sand quality necessitates the use of reliable control equipment and evaluation procedures. This study outlines the scope and results of research work aimed to improve the control equipment to enhance the performance of turbine mixers. The paper reviews the m...

  14. Evaluate of head loss, sediment value and copper removal in sand media (rapid sand filter

    Directory of Open Access Journals (Sweden)

    Daneshi Navab

    2014-06-01

    Full Text Available Along with the technology development and increasing consumption of water resources, we are experiencing low qualities in the mentioned resources. Copper brings about serious environment al pollution, threatening human health and ecosystem. This metal found variously in water resources and industrial activities. Therefore, it needs to treat the water resources from these excessive amounts. Different methods have used for this reason but the most used method during recent years has been the absorption by economic absorbers such as sand. Rapid sand filters usually used in water and wastewater treatment plants for water clarification. In this research, a single layer gravity rapid sand filter has used to reduce different concentrations of copper. sediment value and head loss arising in filter media is simulated by using combination of Carman-Kozeny, Rose and Gregory models in different discharges of rapid sand filter. Results have shown that with increasing in discharge and decreasing in input copper concentration, arriving time to given head loss, is increasing. In addition, results demonstrated that with increasing in copper concentration in influent, removal efficiency is decreasing somewhat. Results of this research can applied in an appropriate design of rapid sand filter to copper removal, a prediction of rapid sand filter ability to copper removal and an estimation of arising head loss during filter work thus evaluating of time interval backwash. DOI: http://dx.doi.org/10.3126/ije.v3i2.10641 International Journal of the Environment Vol.3(2 2014: 276-286

  15. Phase 1 summaries of radionuclide concentration data for vegetation, river water, drinking water, and fish

    International Nuclear Information System (INIS)

    Denham, D.H.; Dirkes, R.L.; Hanf, R.W.; Poston, T.M.; Thiede, M.E.; Woodruff, R.K.

    1993-06-01

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at the Hanford Site since 1944. As part of the HEDR Project, the Environmental Monitoring Data Task (Task 05) staff assemble, evaluate, and summarize key historical measurements of radionuclide concentrations in the environment as a result of Hanford operations. The scope of work performed during Phase I included initiating the search, recovery, and inventory of environmental reports. Summaries of the environmental monitoring data that were recovered and evaluated are presented for specific periods of interest. These periods include vegetation monitoring data (primarily sagebrush) for the years 1945 through 1947, Columbia River water and drinking water monitoring data for the years 1963 through 1966, and fish monitoring data for the years 1964 through 1966. Concern was limited to those radionuclides identified as the most likely major contributors to the dose potentially received by the public during the times of interest: phosphorous-32, copper-64, zinc-65, arsenic-76, and neptunium-239 in Columbia River fish and drinking water taken from the river, and iodine-131 in vegetation. This report documents the achievement of the Phase I objectives of the Environmental Monitoring Data Task

  16. Dewatering Behaviour of Fine Oil Sands Tailings : An Experimental Study

    NARCIS (Netherlands)

    Yao, Y.

    2016-01-01

    Oil sands tailings are a warm aqueous suspension of sand, silt, clay, residual bitumen and naphtha. The tailings are hydraulically transported and stored in tailing ponds where they segregate, with the sand settling from suspension forming beaches and the remaining tailings flowing to the middle of

  17. Design and Fabrication of a Foundry Sand Mixer Using Locally ...

    African Journals Online (AJOL)

    Most small foundry shops mix their sand manually which is not efficient since homogenous mix cannot be guaranteed and even when foundry mixer are available most of them are imported costing the nation huge foriegn exchange. A foundry sand mixer capable of mixing foundry sand has been designed and fabricated ...

  18. Seasonal changing sand waves and the effect of surface waves

    NARCIS (Netherlands)

    Sterlini, Fenneke; van Dijk, Thaiënne A.G.P.; IJzer, Steven; Hulscher, Suzanne; Schüttrumpf, Holger; Tomasicchio, Guiseppe Roberto

    2012-01-01

    Sand waves are wavelike subaqueous sediment structures that exist in large areas in shelf seas. Due to their characteristics sand waves can severely affect human offshore activities, such as navigation. This makes it important to understand the physical processes that shape and change sand waves. In

  19. Short Communications Sand moisture as a factor determining depth ...

    African Journals Online (AJOL)

    1993-11-05

    Nov 5, 1993 ... The depths to which the animals burrow are, at least partly. determined by the moisture gradient in the sand. They are, however, incapable of burrowing into totally dry sand. Animals alter their position in the sand in response to changes in moisture content so as to ensure exposure to suitable conditions.

  20. Assessing environmental impacts of inland sand mining in parts of ...

    African Journals Online (AJOL)

    Sand is a valuable resource for construction and other purposes, however sand mining often result in serious environmental problems such as land degradation, loss of agricultural lands and biodiversity, as well increased poverty among people. This study assessed the environmental impacts of inland sand mining in six ...

  1. Acetylcholinesterase mutations and organophosphate resistance in sand flies and mosquitoes

    Science.gov (United States)

    Leishmaniasis is an insect-borne disease caused by several protozoan species in the genus Leishmania, which are vectored by sand fly species in the genera Phlebotomus or Lutzomyia, depending on the sand fly species geographic range. Sand fly bites and leishmaniasis significantly impacted U.S. milita...

  2. Sand Needs and Resources Offshore New York

    Science.gov (United States)

    Lashley, J. M.; Flood, R. D.; White, M.; Bokuniewicz, H.; Hinrichs, C.; Wilson, R. E.

    2016-02-01

    "Superstorm" Sandy (October, 2012) accentuated the persistent problem of coastal erosion on New York's ocean coast. The New York state Department of State in cooperation with the Bureau of Ocean Energy Management has initiated further identification and assessment of marine sand reserves required to improve the resiliency of coastal communities and the maintenance of coastal habitats. The historical demand for beach nourishment has been about 1.5 million cubic meters per year, but sea level rise and the occurrence of extreme conditions may increase the demand to over 5 million cubic meters annually. Forty-four historical and proposed borrow sites have been delineated. This inner shelf is both sand rich and data rich. Geophysical and geological data has been compiled and reassessed to support identification, characterization, and delineation of sand resources for potential use in future coastal restoration, beach nourishment, and/or wetland restoration efforts. The South Shore of Long Island is composed in part by the Fire Island National Seashore. Holocene sand ridges extending at an oblique angle to the cross shore in the seaward direction. Borrow pits among the sand ridges, excavated were apparent in the most recent surveys and it appears that natural replenishment of offshore borrow areas has been occurring although the rates need to be determined in order to assess their sustainability. Not only is the area one of intense societal attention, but the use of this resource for coastal resilience must fit into a diverse framework marine spatial planning including not only traditional components, like commercial fishing, but also new factors like the siting of offshore wind-farms. To extend this assessment will include a recent survey, sponsored by the Bureau of Ocean Energy Management and the New York Department of State, providing approximately 700 km of geophysical survey lines located between 3 and 9 nautical miles offshore, and 46 geotechnical samples

  3. The Rheology of Acoustically Fluidized Sand

    Science.gov (United States)

    Conrad, J. W.; Melosh, J.

    2013-12-01

    The collapse of large craters and the formation of central peaks and peak rings is well modeled by numerical computer codes that incorporate the acoustic fluidization mechanism to temporarily allow the fluid-like flow of rock debris immediately after crater excavation. Furthermore, long runout landslides require a similar mechanism to explain their almost frictionless movement, which is probably also a consequence of their granular composition coupled with internal vibrations. Many different investigators have now confirmed the ability of vibrations to fluidize granular materials. Yet it still remains to fully describe the rheology of vibrated sand as a function of stress, frequency and amplitude of the vibrations in the sand itself. We constructed a rotational viscometer to quantitatively investigate the relation between the stress and strain rate in a horizontal bed of strongly vibrated sand. In addition to the macroscopic stain rate, the amplitude and frequency of the vibrations produced by a pair of pneumatic vibrators were also measured with the aid of miniaturized piezoelectric accelerometers (B&K 4393) whose output was recorded on a digital storage oscilloscope. The initial gathering of the experimental data was difficult due to granular memory, but by having the sand compacted vibrationally for 8 minutes before each run the scatter of data was reduced and we were able to obtain consistent results. Nevertheless, our major source of uncertainty was variations in strain rate from run to run. We find that vibrated sand flows like a highly non-Newtonian fluid, in which the shear strain rate is proportional to stress to a power much greater than one, where the precise power depends on the amplitude and frequency of the applied vibrations. Rapid flow occurs at stresses less than half of the static yield stress (that is, the yield stress when no vibration is applied) when strong vibrations are present. For a Newtonian fluid, such as water, the relation between

  4. Baseline vegetation inventory and productivity assessment for the Syncrude Aurora Mine EIA local study area

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    This report presented an inventory and assessment of vegetation communities and forest covers within the proposed Aurora Mine local study area. A field inventory was conducted in the summer of 1995 to ground-truth air photo interpretations and to collect data. The inventory includes a classification of vegetation, forest covers and wetlands. It also includes the documentation of uncommon plants and the vegetation productivity estimates of tree, shrub and herbaceous plants. The study area is located east of the Athabasca River about 35 km northeast of Mildred Lake Oil Sands Plant. The area includes portions of Oil Sands Leases 10, 12, 13, 31, and 34 which includes much of the Muskeg River drainage and all of Kearl Lake. 24 refs., 7 tabs., 3 figs.

  5. Wind tunnel experiments of air flow patterns over nabkhas modeled after those from the Hotan River basin,Xinjiang,China(Ⅱ):vegetated

    Institute of Scientific and Technical Information of China (English)

    Zhizhong LI; Rong MA; ShengLi WU; Janis DALE; Lin GE; Mudan HE; Xiaofeng WANG; Jianhui JIN; Jinwei LIU; Wanjuan LI

    2008-01-01

    This paper examines the results of wind tunnel experiments on models of nabkha,based on those studied in the Hotan River basin.Semi-spherical and conical models of nabkhas were constructed at a ratio of 40:1 in light of the on-site observation.Artificial vegetation of simulated Tamarix spp.was put on top of each model.Parameters of the shape,including height,width,and diameter of vegetated semi-spherical and conical nabkha.were measured in the Hotan River basin.Wind tunnel experiments on the semi-spherical and conical nabkha used clean air devoid of additional sediments at five different wind speeds (6-14 m/s)to study the influence of vegetation on airflow patterns.Results of the experiments indicate that vegetation at the top of the nabkhas enhances the surface roughness of the sand mounds,retards airflow over the sand mounds,reduces airflow energy,eliminates erosional pits occurring on the top surface of non-vegetated sand mounds and enhances the range of influence of the vortex that forms on the leeward slope.Vegetation changes the airflow pattern upwind and downwind of the sand mound and reduces the transport of sand away from the nabkha.This entrapment of sediment by the vegetation plays an important role in sustaining the nabkha landscape of the study area.The existence of vegetation makes fine materials in wind-sand flow to possibly deposit,and promotes nabkha formation.The imitative flow patterns Of different morphological nabkhas have also been verified by on-site observation in the river basin.

  6. System Controls on the South Texas Sand Sheet

    Science.gov (United States)

    Barrineau, Clifton Patrick

    Semi-stabilized dune systems are important indicators of Quaternary drought variability across central North America. The South Texas sand sheet (STSS) is the southernmost relict dune system in central North America and is exposed to higher evapotranspiration and moisture variability than similar landscapes farther north. This study uses multi-scale analysis of LiDAR data, geophysical surveys, optically stimulated luminescence dates of core samples, and X-ray fluorescence analysis to identify historical periods of desertification across the STSS. These data suggest long-term relationships between climate, ecological disturbances, geological framework, and desertification. Aeolian activations dated at ca. 75, 230, 2000, 4100, and 6600 yr bp correspond to periods of persistent regional drought, changes in sediment supply, and anthropogenic disturbances of native ecology. From these results it appears that regionalized activation in semi-stabilized dune systems is controlled primarily by climatic variations that reduce the overall moisture available for maintaining vigorous vegetation growth, while localized activation patterns depend more on stresses related to site-specific morphodynamics as well as human activity. With enhanced aridity forecast for much of central North America through the 21 st century, understanding the specific thresholds of desertification is an important step towards building a conceptual model of desertification in semi-stabilized dune landscapes.

  7. Lessons learned from comparisons of mesotidal sand- and mudflats

    Science.gov (United States)

    Nittrouer, Charles A.; Raubenheimer, Britt; Wheatcroft, Robert A.

    2013-06-01

    Tidal flats with limited vegetation provide valuable opportunities to investigate the linkages of hydrodynamics and sediment dynamics. A mudflat in southern Willapa Bay and a sandflat in Skagit Bay (both Washington state, USA) are characterized by processes with many similarities, but some differences. In particular, one imports mud and the other exports mud. Classic intertidal mechanisms (e.g., flood/ebb asymmetry, settling/scour lags) cause net landward transport onto the southern Willapa tidal flat, and the details of the interlinked processes are complex. Meandering channels with dendritic planform are the circulatory system for this site, and are entrenched in cohesive clayey silt. Tidal range and wind/wave conditions are similar in the two areas, but the direct discharges of fluvial freshwater and sediment are much greater for Skagit Bay. When coupled with the other processes operating there, mud export from the Skagit tidal flat is the net result. Braided channels dominate the Skagit site, and migrate freely through non-cohesive fine sand. An integrated summary is presented here for a multi-investigator study of these two areas, and the detailed results are described by the papers that follow.

  8. The physics of wind-blown sand and dust.

    Science.gov (United States)

    Kok, Jasper F; Parteli, Eric J R; Michaels, Timothy I; Karam, Diana Bou

    2012-10-01

    The transport of sand and dust by wind is a potent erosional force, creates sand dunes and ripples, and loads the atmosphere with suspended dust aerosols. This paper presents an extensive review of the physics of wind-blown sand and dust on Earth and Mars. Specifically, we review the physics of aeolian saltation, the formation and development of sand dunes and ripples, the physics of dust aerosol emission, the weather phenomena that trigger dust storms, and the lifting of dust by dust devils and other small-scale vortices. We also discuss the physics of wind-blown sand and dune formation on Venus and Titan.

  9. Longshore sediment transport at Golden Sands (Bulgaria

    Directory of Open Access Journals (Sweden)

    Hristo Nikolov

    2006-09-01

    Full Text Available The paper presents the results of studies on the qualitative and quantitative features of the littoral drift at Golden Sands (Bulgaria, carried out jointly by Polish and Bulgarian researchers. The mathematical modelling of physical coastal processes took wave transformation (wave diffraction and refraction; the effects of shoaling and wave breaking and longshore sediment transport into account. The computations were carried out for the mean statistical annual wave climate, determined on the basis of IO BAS wave data, simulated using the WAM method from long-term Black Sea wind data. The results of sediment transport computations clearly show that its direction off the Golden Sands shore is from north to south.

  10. Oil sands tailings preliminary ecological risk assessment

    International Nuclear Information System (INIS)

    1994-01-01

    Chemical data collected from various oil sands soil-tailings mixtures were used to determine the ecological risk that such tailings would pose to terrestrial wildlife at the surface of a reclaimed site. A methodology that could be used to evaluate the risks posed by various reclamation options (for dry land only) was proposed. Risks associated with other reclamation options, such as wet landscapes or deeper in-pit disposal, were not evaluated. Ten constituents (eight organic and two inorganic) were found to pose a threat to terrestrial biota. The relative contribution of different exposure pathways (water and food ingestion, incidental soil ingestion, inhalation) were studied by probabilistic models. Some physical and chemical reclamation alternatives which involve incorporating oil sands tailings in the landscape to produce a surface that could sustain a productive ecosystem, were described. 53 refs., 15 tabs., 3 figs

  11. Tailings dewatering in the oil sands

    Energy Technology Data Exchange (ETDEWEB)

    Longo, S.; Labelle, M. [Golder Paste Technology, Sudbury, ON (Canada); Wislesky, I. [Golder Associates Ltd., Calgary, AB (Canada)

    2010-07-01

    Alberta's Directive 074 was established to reduce fluid tailings produced during oil sands extraction processes. This PowerPoint presentation examined some of the dewatering strategies available for oil sands operators and provided recommendations for implementing a dewatering plan. Sites must be evaluated in order to determine their chemistry, mineralogy, and the total quantity of material to be handled. The availability of potential additives must also be considered. Process technologies must be selected in relation to the operator's depositional strategy. Each site will require its own unique dewatering and depositional strategy. Dewatering technologies include thickening; in-line flocculation; centrifuge; co-mingling; and various new technologies such as electro-osmosis. Laboratory testing programs include index tests, primary stream thickening, and mini-pilot plant testing. The performance of various testing formats was evaluated. Thickening and depositional techniques were reviewed. tabs., figs.

  12. Radiation protection in the sand pit

    International Nuclear Information System (INIS)

    Hewson, Greg

    1997-01-01

    Radiation protection in the Western Australian minerals sands industry has attracted considerable controversy over the last 20 years: firstly, in relation to environmental and public health issues associated with the indiscriminate disposal of radioactive tailings as landfill in the mid to late 1970s and, secondly, in relation to occupational health issues associated with excessive radiation exposures to some workers at some plants in the mid to late 1980s. The industry also attracts attention through its proximity to coastal regions and population centres and consequent land use conflicts. Owing to intense political and societal scrutiny, and the emotional responses evoked by radiation, the industry's survival depends on a continuing high level of environmental and safety performance. This article summarises the successes and failures of the mineral sands industry in managing radiation protection and highlights some future issues and challenges for the industry. (Author)

  13. Oil sands market and transportation solutions

    International Nuclear Information System (INIS)

    Sandahl, R.

    2004-01-01

    This presentation outlined the immense potential of the western Canadian oil sands reserves. Recoverable reserves have been estimated at 180 billion barrels, with production forecasts estimated at 5 million barrels per day by 2030. Resource development is occurring at a time when the world's largest oil importer is increasing supplies through concern for security of supply. The second and third largest oil importers in the world are experiencing economic and energy demand growth. These factors underscore the motivation for rapid growth of the Western Canadian Oil Sands reserves. One of the challenges that must be addressed is to ensure that incremental markets for the increased production are accessed. Another challenge is to ensure adequate infrastructure in terms of pipeline capacity to ensure deliverability of the product. tabs., figs

  14. Vegetation Identification With LIDAR

    National Research Council Canada - National Science Library

    Helt, Michael F

    2005-01-01

    .... The specific terrain element of interest is vegetation, and in particular, tree type. Data taken on April 12th, 2005, were taken over a 10 km 20 km region which is mixed use agriculture and wetlands...

  15. Pullout capacity of batter pile in sand.

    Science.gov (United States)

    Nazir, Ashraf; Nasr, Ahmed

    2013-03-01

    Many offshore structures are subjected to overturning moments due to wind load, wave pressure, and ship impacts. Also most of retaining walls are subjected to horizontal forces and bending moments, these forces are due to earth pressure. For foundations in such structures, usually a combination of vertical and batter piles is used. Little information is available in the literature about estimating the capacity of piles under uplift. In cases where these supporting piles are not vertical, the behavior under axial pullout is not well established. In order to delineate the significant variables affecting the ultimate uplift shaft resistance of batter pile in dry sand, a testing program comprising 62 pullout tests was conducted. The tests are conducted on model steel pile installed in loose, medium, and dense sand to an embedded depth ratio, L/d, vary from 7.5 to 30 and with various batter angles of 0°, 10°, 20°, and 30°. Results indicate that the pullout capacity of a batter pile constructed in dense and/or medium density sand increases with the increase of batter angle attains maximum value and then decreases, the maximum value of Pα occurs at batter angle approximately equal to 20°, and it is about 21-31% more than the vertical pile capacity, while the pullout capacity for batter pile that constructed in loose sand decreases with the increase of pile inclination. The results also indicated that the circular pile is more resistant to pullout forces than the square and rectangular pile shape. The rough model piles tested is experienced 18-75% increase in capacity compared with the smooth model piles. The suggested relations for the pullout capacity of batter pile regarding the vertical pile capacity are well predicted.

  16. Fusion of arkosic sand by intrusive andesite

    Science.gov (United States)

    Bailey, Roy A.

    1954-01-01

    An andesite dike in the Valles Mountains of northern New Mexico has intruded and partly fused arkosic sediments for a distance of 50 feet from its contacts. The dike is semi-circular in form, has a maximum width of about 100 feet, and is about 500 feet long. Small associated arcuate dikes are arranged in spiral fashion around the main dike, suggesting that they were intruded along shear fractures similar to those described by Burbank (1941). The fused rocks surrounding the andesite dike are of three general types: 1) partly fused arkosic sand, 2) fused clay, and 3) hybrid rocks. The fused arkosic sand consists of relict detrital grains of quartz, orthoclose, and plagioclase, imbedded in colorless glass containing microlites of tridymite, cordierite, and magnetite. The relict quartz grains are corroded and embayed by glass; the orthoclase is sanidinized and partly fused; and the plagioclase is inverted to the high temperature form and is partly fused. The fused clay, which was originally a mixture of montmorillonite and hydromica, consists primarily of cordierite but also contains needle-like crystals of sillimanite (?) or mullite (?). The hybrid rocks originated in part by intermixing of fused arkosic sediments and andesitic liquid and in part by diffusion of mafic constituents through the fused sediments. They are rich in cordierite and magnetite and also contain hypersthene, augite, and plagioclase. The composition of pigeonite in the andesite indicates that the temperature of the andesite at the time of intrusion probably did not exceed 1200?C. Samples of arkosic sand were fused in the presence of water in a Morey bomb at 1050?C. Stability relations of certain minerals in the fused sand suggest that fusion may have taken place at a lower temperature, however, and the fluxing action of volatiles from the andesite are thought to have made this possible.

  17. Solvent extraction of Southern US tar sands

    Energy Technology Data Exchange (ETDEWEB)

    Penney, W.R.

    1990-01-01

    The Department of Chemical Engineering at the University of Arkansas, in association with Diversified Petroleum Recovery, Inc. (DPR) of Little Rock, Arkansas, has been developing a solvent extraction process for the recovery of bitumen from tar sands for the past five years. The unique feature of the process is that the bitumen is recovered from the solvent by contacting with a co-solvent, which causes the bitumen to precipitate. The overall purpose of this project is to study both the technical and economic feasibility of applying this technology for recovery of bitumen from tar sands by (1) investigating the socioeconmic factors which affect (a) plant siting and (b) the market value of recovered bitumen; (2) operating a process demonstration unit at the rate of 1 lb/hr recovered bitumen while producing clean sand and recyclable solvents; and (3) determine the economic conditions which will make a bitumen recovery project economical. DPR has analyzed the historical trends of domestic production, consumption, discoveries and reserves of crude oil. They have started an investigation of the volatility in the price of crude oil and of gasoline prices and of the differential between gasoline and crude oil. DPR continues to analyze the geographical movement and demand for asphalt products. Utah does not appear economically attractive as a site for a bitumen from tar sands asphalt plant. Oklahoma sites are now being studied. This report also contains the quarterly progress report from a University of Nevada study to determine bitumen composition, oxygen uptake rates, and viscosities of Alabama and Utah bitumens. Both reports have been indexed separately for inclusion on the data base.

  18. Comparison of SAND-II and FERRET

    International Nuclear Information System (INIS)

    Wootan, D.W.; Schmittroth, F.

    1981-01-01

    A comparison was made of the advantages and disadvantages of two codes, SAND-II and FERRET, for determining the neutron flux spectrum and uncertainty from experimental dosimeter measurements as anticipated in the FFTF Reactor Characterization Program. This comparison involved an examination of the methodology and the operational performance of each code. The merits of each code were identified with respect to theoretical basis, directness of method, solution uniqueness, subjective influences, and sensitivity to various input parameters

  19. Drained Triaxial Tests on Eastern Scheldt Sand

    DEFF Research Database (Denmark)

    Praastrup, U.; Jakobsen, Kim Parsberg

    In the process of understanding and developing models for geomaterials, the stress-strain behaviour is commonly studied by performing triaxial tests. In the present study static triaxial tests have been performed to gain knowledge of the stress-strain behaviour of frictional materials during...... monotonic loading. The tests reported herein are all drained tests, starting from different initial states of stress and following various stress paths. AIl the tests are performed on reconstituted medium dense specimens of Eastern Scheldt Sand....

  20. Pullout capacity of batter pile in sand

    Directory of Open Access Journals (Sweden)

    Ashraf Nazir

    2013-03-01

    Full Text Available Many offshore structures are subjected to overturning moments due to wind load, wave pressure, and ship impacts. Also most of retaining walls are subjected to horizontal forces and bending moments, these forces are due to earth pressure. For foundations in such structures, usually a combination of vertical and batter piles is used. Little information is available in the literature about estimating the capacity of piles under uplift. In cases where these supporting piles are not vertical, the behavior under axial pullout is not well established. In order to delineate the significant variables affecting the ultimate uplift shaft resistance of batter pile in dry sand, a testing program comprising 62 pullout tests was conducted. The tests are conducted on model steel pile installed in loose, medium, and dense sand to an embedded depth ratio, L/d, vary from 7.5 to 30 and with various batter angles of 0°, 10°, 20°, and 30°. Results indicate that the pullout capacity of a batter pile constructed in dense and/or medium density sand increases with the increase of batter angle attains maximum value and then decreases, the maximum value of Pα occurs at batter angle approximately equal to 20°, and it is about 21–31% more than the vertical pile capacity, while the pullout capacity for batter pile that constructed in loose sand decreases with the increase of pile inclination. The results also indicated that the circular pile is more resistant to pullout forces than the square and rectangular pile shape. The rough model piles tested is experienced 18–75% increase in capacity compared with the smooth model piles. The suggested relations for the pullout capacity of batter pile regarding the vertical pile capacity are well predicted.

  1. Transport processes in intertidal sand flats

    Science.gov (United States)

    Wu, Christy

    2010-05-01

    Methane rich sulfate depleted seeps are observed along the low water line of the intertidal sand flat Janssand in the Wadden Sea. It is unclear where in the flat the methane is formed, and how it is transported to the edge of the sand flat where the sulfidic water seeps out. Methane and sulfate distributions in pore water were determined along transects from low water line toward the central area of the sand flat. The resulting profiles showed a zone of methane-rich and sulfate-depleted pore water below 2 m sediment depth. Methane production and sulfate reduction are monitored over time for surface sediments collected from the upper flat and seeping area. Both activities were at 22 C twice as high as at 15 C. The rates in sediments from the central area were higher than in sediments from the methane seeps. Methanogenesis occurred in the presence of sulfate, and was not significantly accelerated when sulfate was depleted. The observations show a rapid anaerobic degradation of organic matter in the Janssand. The methane rich pore water is obviously transported with a unidirectional flow from the central area of the intertidal sand flat toward the low water line. This pore water flow is driven by the pressure head caused by elevation of the pore water relative to the sea surface at low tide (Billerbeck et al. 2006a). The high methane concentration at the low water line accumulates due to a continuous outflow of pore water at the seepage site that prevents penetration of electron acceptors such as oxygen and sulfate to reoxidize the reduced products of anaerobic degradation (de Beer et al. 2006). It is, however, not clear why no methane accumulates or sulfate is depleted in the upper 2 m of the flats.

  2. Guide to preparing SAND reports. Revised

    Energy Technology Data Exchange (ETDEWEB)

    Locke, T.K. [ed.

    1996-04-01

    This guide contains basic information needed to produce a SAND report. Its guidelines reflect DOE regulation and Sandia policy. The guide includes basic writing instructions in an annotated sample report; guidance for organization, format, and layout of reports produced by line organizations; and information about conference papers, journal articles, and brochures. The appendixes contain sections on Sandia`s preferred usage, equations, references, copyrights and permissions, and publishing terms.

  3. Analysis of wind-blown sand movement over transverse dunes.

    Science.gov (United States)

    Jiang, Hong; Huang, Ning; Zhu, Yuanjian

    2014-12-01

    Wind-blown sand movement often occurs in a very complicated desert environment where sand dunes and ripples are the basic forms. However, most current studies on the theoretic and numerical models of wind-blown sand movement only consider ideal conditions such as steady wind velocity, flat sand surface, etc. In fact, the windward slope gradient plays a great role in the lift-off and sand particle saltation. In this paper, we propose a numerical model for the coupling effect between wind flow and saltating sand particles to simulate wind-blown sand movement over the slope surface and use the SIMPLE algorithm to calculate wind flow and simulate sands transport by tracking sand particle trajectories. We furthermore compare the result of numerical simulation with wind tunnel experiments. These results prove that sand particles have obvious effect on wind flow, especially that over the leeward slope. This study is a preliminary study on windblown sand movement in a complex terrain, and is of significance in the control of dust storms and land desertification.

  4. Vegetation and soils

    Science.gov (United States)

    Burke, M.K.; King, S.L.; Eisenbies, M.H.; Gartner, D.

    2000-01-01

    Intro paragraph: Characterization of bottomland hardwood vegetation in relatively undisturbed forests can provide critical information for developing effective wetland creation and restoration techniques and for assessing the impacts of management and development. Classification is a useful technique in characterizing vegetation because it summarizes complex data sets, assists in hypothesis generation about factors influencing community variation, and helps refine models of community structure. Hierarchical classification of communities is particularly useful for showing relationships among samples (Gauche 1982).

  5. Naphtha evaporation from oil sands tailings ponds

    Energy Technology Data Exchange (ETDEWEB)

    Kasperski, K.; Munoz, V.; Mikula, R. [Natural Resources Canada, Devon, AB (Canada). CANMET Western Research Centre

    2010-07-01

    The environmental impacts of volatile organic compounds (VOCs) from oil sands tailings ponds must be considered when evaluating new oil sands mining and extraction operations. Studies have suggested that only 40 percent of the solvent sent to tailings ponds is available to the environment, while the rest is irreversibly trapped. The recovery of hydrocarbons from oil sands froth process water is low. This PowerPoint presentation discussed a method of distinguishing between water and hydrocarbons at low temperatures. Samples were heated to 246 degrees C at 15 degrees C and held for 10 minutes. Heating was then resumed at 750 degrees C and held for 10 minutes in a pyrolysis phase, then cooled and reheated with an oxygen addition. The method demonstrated that the diluent distribution between the solids and water phases is misinterpreted as diluent that will evaporate, and diluent that will not evaporate. The study concluded by suggesting that the definition of recoverable and unrecoverable hydrocarbon should be re-termed as easily recoverable, and difficult to recover. tabs., figs.

  6. Insight conference reports : Western Canada oil sands

    International Nuclear Information System (INIS)

    2005-01-01

    This conference presented issues of concern to the Canadian oil sands industry. Focal points included supply and the potential for market growth as well as opportunities and challenges faced by the industry in the current market. Various projects were discussed, including the Northern Lights and Fort Hill projects. Reserves and resource booking procedures were examined, as well as issues concerning the streamlining of regulatory barriers and various approaches to the Kyoto Protocol and greenhouse gas (GHG) emissions. Oil sands portfolios were reviewed as well as issues concerning the recovery of titanium and zircon, the economics of Steam Assisted Gravity Drainage (SAGD) options and innovations in technology and sub-surface risk assessment for in-situ projects. Transportation initiatives were examined as well as pipeline issues and storage infrastructure development. Issues concerning financing as well as the economic environment of the oil sands industry were also discussed. The conference featured 20 presentations, of which 5 have been catalogued separately for inclusion in this database. tabs, figs

  7. Recycled sand in lime-based mortars.

    Science.gov (United States)

    Stefanidou, M; Anastasiou, E; Georgiadis Filikas, K

    2014-12-01

    The increasing awareness of the society about safe guarding heritage buildings and at the same time protecting the environment promotes strategies of combining principles of restoration with environmentally friendly materials and techniques. Along these lines, an experimental program was carried out in order to investigate the possibility of producing repair, lime-based mortars used in historic buildings incorporating secondary materials. The alternative material tested was recycled fine aggregates originating from mixed construction and demolition waste. Extensive tests on the raw materials have been performed and mortar mixtures were produced using different binding systems with natural, standard and recycled sand in order to compare their mechanical, physical and microstructure properties. The study reveals the improved behavior of lime mortars, even at early ages, due to the reaction of lime with the Al and Si constituents of the fine recycled sand. The role of the recycled sand was more beneficial in lime mortars rather than the lime-pozzolan or lime-pozzolan-cement mortars as a decrease in their performance was recorded in the latter cases due to the mortars' structure. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Numerical simulation of sand jet in water

    Energy Technology Data Exchange (ETDEWEB)

    Azimi, A.H.; Zhu, D.; Rajaratnam, N. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering

    2008-07-01

    A numerical simulation of sand jet in water was presented. The study involved a two-phase flow using two-phase turbulent jets. A literature review was also presented, including an experiment on particle laden air jet using laser doppler velocimetry (LDV); experiments on the effect of particle size and concentration on solid-gas jets; an experimental study of solid-liquid jets using particle image velocimetry (PIV) technique where mean velocity and fluctuations were measured; and an experimental study on solid-liquid jets using the laser doppler anemometry (LDA) technique measuring both water axial and radial velocities. Other literature review results included a photographic study of sand jets in water; a comparison of many two-phase turbulent flow; and direct numerical simulation and large-eddy simulation to study the effect of particle in gas jet flow. The mathematical model and experimental setup were also included in the presentation along with simulation results for sand jets, concentration, and kinetic energy. The presentation concluded with some proposed future studies including numerical simulation of slurry jets in water and numerical simulation of slurry jets in MFT. tabs., figs.

  9. Mobil Oil Canada : Kearl Oil Sands Mine

    International Nuclear Information System (INIS)

    1997-01-01

    The upgrader design at Mobil's Kearl Oil Sands Mine were described. Included were feed characteristics, upgrader products, process schemes and their overall economics and upgrader technologies in use, including coking, deasphalting, hydrocracking, hydrotreating and visbreaking. Advantages and disadvantages of the upgrader technologies were highlighted. As far as the product is concerned, much of it is destined to U.S. refineries that are equipped to process the material. The Kearl Oil Sands Mine upgrading facility will likely use a combination of coker/hydrotreating, which is a well proven process for high value products that has been used in all five of Mobil's refineries in the U.S., and visbreaker/deasphalting, which has shown promise in bench-scale testing, but at present still has some potential commercial difficulties. Foremost among these are the high softening product of asphalt from visbroken products, questionable commercial feasibility of the low yield of pitch, and problems in the disposal of asphalt. Severe visbreaking also yields unstable products. Details of Mobil Canada's oil sands project were also summarized 2 tabs., 9 figs

  10. Experimental investigation of sanding propensity for the Andrew completion

    Energy Technology Data Exchange (ETDEWEB)

    Venkitaraman, A.; Li, H. [Schlumberger Perforating and Testing Center (United Kingdom); Leonard, A. J.; Bowden, P. R. [BP Exploration (United Kingdom)

    1998-12-31

    A series of laboratory experiments were performed on three reservoir core samples selected from two plot wells to confirm the likelihood of sand production during the completion phase of the planned Andrew horizontal wells, and to perform risk analysis of formation failure at the time of underbalance perforation, and expected producing conditions. CT scans revealed no perforation failure, and the core samples did not show any propensity to produce sand during single-phase oil flow. Transient sand production was observed when water cut was introduced, but sand production declined as the percentage of water cut was increased. There was no evidence of sand production in the core samples during depletion testing either, and the wells were subsequently completed with perforated cemented liners without sand control. No sand problems have been encountered in two years of production, with some wells in water cut and declined reservoir pressure of 200 psi. 8 refs., 3 tabs., 5 figs.

  11. Use of sand wave habitats by silver hake

    Science.gov (United States)

    Auster, P.J.; Lindholm, J.; Schaub, S.; Funnell, G.; Kaufman, L.S.; Valentine, P.C.

    2003-01-01

    Silver hake Merluccius bilinearis are common members of fish communities in sand wave habitats on Georges Bank and on Stellwagen Bank in the Gulf of Maine. Observations of fish size v. sand wave period showed that silver hake are not randomly distributed within sand wave landscapes. Regression analyses showed a significant positive relationship between sand wave period and fish length. Correlation coefficients, however, were low, suggesting other interactions with sand wave morphology, the range of current velocities, and available prey may also influence their distribution. Direct contact with sand wave habitats varied over diel periods, with more fish resting on the seafloor during daytime than at night. Social foraging, in the form of polarized groups of fish swimming in linear formations during crepuscular and daytime periods, was also observed. Sand wave habitats may provide shelter from current flows and mediate fish-prey interactions. ?? 2003 The Fisheries Society of the British Isles.

  12. bentonite-sand mixture as new backfill/buffer material

    International Nuclear Information System (INIS)

    Cui Suli; Liu Jisheng; Zhang Huyuan; Liang Jian

    2008-01-01

    The mixture of bentonite and quartz sand is suggested as a new backfill/buffer material for geological disposal of HLW. To improve the further design of underground laboratory and in-situ industrial construction test, the optimization of sand addition to bentonite is focused at present research stage. Based on summarizing the research results abroad, laboratory tests were conducted on the mixture of GMZ001 bentonite and quartz sand, such as compaction test and swelling tests etc. Test data shows that GMZ bentonite-sand mixture exhibits a favorite compaction with a 30% sand addition, a highest swelling pressure with a 20% sand addition, and a decreasing plasticity with increases in sand addition and pore liquid concentration. (authors)

  13. Sand wave fields beneath the Loop Current, Gulf of Mexico: Reworking of fan sands

    Science.gov (United States)

    Kenyon, Neil H.; Akhmetzhanov, A.M.; Twichell, D.C.

    2002-01-01

    Extensive fields of large barchan-like sand waves and longitudinal sand ribbons have been mapped by deep-towed SeaMARC IA sidescan sonar on part of the middle and lower Mississippi Fan that lies in about 3200 m of water. The area is beneath the strongly flowing Loop Current. The bedforms have not been adequately sampled but probably consist of winnowed siliciclastic-foraminiferal sands. The size (about 200 m from wingtip to wingtip) and shape of the large barchans is consistent with a previously observed peak current speed of 30 cm/s, measured 25 m above the seabed. The types of small-scale bedforms and the scoured surfaces of chemical crusts, seen on nearby bottom photographs, indicate that near-bed currents in excess of 30 cm/s may sometimes occur. At the time of the survey the sand transport direction was to the northwest, in the opposite direction to the Loop Current but consistent with there being a deep boundary current along the foot of the Florida Escarpment. Some reworking of the underlying sandy turbidites and debris flow deposits is apparent on the sidescan sonar records. Reworking by deep-sea currents, resulting in erosion and in deposits characterised by coarsening upwards structures and cross-bedding, is a process that has been proposed for sand found in cores in shallower parts of the Gulf of Mexico. This process is more widespread than hitherto supposed. 

  14. Seasonal energy, water, and food consumption of Negev Chukars and sand partridges

    International Nuclear Information System (INIS)

    Kam, M.; Degen, A.A.; Nagy, K.A.

    1987-01-01

    Chukars (Alectoris chukar) and Sand Partridges (Ammoperdix heyl), two ground-dwelling phasianids, are permanent residents of the Negev desert and are sympatric over much of their ranges. Sand Partridges (body mass = 150-250 g), however, inhabit only arid and very arid areas, whereas Chukars (m/sub b/ = 350-600 g) are widely distributed and inhabit deserts only at the margins of their ranges. They compared some of the desert adaptations of these phasianids by measuring the seasonal field metabolic rates (FMR) and water influxes (using doubly labelled water), diet selection, and food requirements of free-living Chukars and Sand Partridges at a site where both species occurred. Both species showed adaptation in the form of low energy metabolism, which ranged from 43 to 81% of that expected for birds of similar body mass. During summer, Sand Partridges had lower energy expenditures (5.47 kJ x g/sup -0.61/ x d -1 ) and water influxes (72.3 mL kg/sup -0.75/ d -1 ) than did Chukars (6.42 kJ g/sup -0.61/ d -1 and 93.5 mL x kg/sup -0.75/ x d -1 , respectively), indicating more pronounced adjustments to arid conditions in the desert specialist. However, both species obtained more than half of their water influx in summer by drinking. Their summer diet was relatively dry, consisting mainly of seeds (80%) along with some green vegetation (18%) and, in Chukars, occasional arthropods. This situation changed abruptly after winter rains, which induced germination and reduced the availability of seeds. Chukars were unable to maintain energy balance in the face of low ambient temperatures and a diet (90% green vegetation) that contained much water but comparatively little energy, and they mobilized fat reserves to meet energy requirements. Most Sand Partridges left the study area after winter rains, apparently migrating to the lower elevation, warmer, and drier Arava (part of the Rift Valley)

  15. Recovery of macrobenthic assemblages following experimental sand burial

    Directory of Open Access Journals (Sweden)

    José J. Barrón

    2008-09-01

    Full Text Available This research was supported by a fund provided by the Instituto de Ciencias del Mar y Limnología (UNAM and a fund provided to Celia Olabarria in 2004 and 2005 by the University of Vigo for overseas short stays.AbstractPeriodic inundation by sand is a very common feature of rocky coasts throughout the world. Even so, there have been few direct observations or experiments to investigate the role of sediments on intertidal rocky shores. We designed a field experiment in Mazatlán Bay, Mexico, to test the initial impact and subsequent recovery of intertidal macrobenthic assemblages exposed to sand burial at two sites of varying wave exposure. Both sites supported different natural assemblages. Treatment plots for the addition of sediment and control plots (50 × 50 cm, separated by at least 1.5 m, were randomly placed across the mid-water tidal level. The initial response of the resident macrobenthos and the subsequent recolonization was monitored over a period of 95 days. The main effect of sediment deposition at both sites was mortality and removal of biota due to smothering. The recovery process was rapid and may in part have been the result of the mechanism by which the small, disturbed patches were recolonized. Most of the invertebrates colonized the patches as adults; several seaweeds exhibited vegetative growth as the major mechanism of colonization (e.g., Ulva lactuca Linnaeus, 1753, Amphiroa valonioides Yendo, 1902 and Chaetomorpha antennina (Borgensen Kutzing, 1849. The rate of recovery varied between the sites, however. Recovery of species numbers proceeded quickly at the sheltered site (day 7, but took 95 days at the exposed site. In contrast, biomass reached control levels by day 45 at the sheltered site, but already by day 15 at the exposed site. By day 95, the assemblages recovered to 83.5% and 81% similarity with the controls at the sheltered and exposed sites respectively. Although differences in wave exposure could be very

  16. Properties of dune sand concrete containing coffee waste

    Directory of Open Access Journals (Sweden)

    Mohamed Guendouz

    2018-01-01

    Full Text Available In the last years, an increase of coffee beverages consumption has been observed all over the world; and its consumption increases the waste coffee grounds which will become an environmental problems. Recycling of this waste to produce new materials like sand concrete appears as one of the best solutions for reduces the problem of pollution. This work aims to study the possibility of recycling waste coffee grounds (Spent Coffee Grounds (SCG as a fine aggregate by replacing the sand in the manufacturing of dune sand concrete. For this; sand concrete mixes were prepared with substitution of sand with the spent coffee grounds waste at different percentage (0%, 5%, 10%, 15% and 20% by volume of the sand in order to study the influence of this wastes on physical (Workability, bulk density and porosity, mechanical (compressive and flexural strength and Thermal (Thermal conductivity and thermal diffusivity properties of dune sand concrete. The results showed that the use of spent coffee grounds waste as partial replacement of natural sand contributes to reduce workability, bulk density and mechanical strength of sand concrete mixes with an increase on its porosity. However, the thermal characteristics are improved and especially for a level of 15% and 20% of substitution. So, it is possible to obtain an insulating material which can be used in the various types of structural components. This study ensures that reusing of waste coffee grounds in dune sand concrete gives a positive approach to reduce the cost of materials and solve some environmental problems.

  17. Policy Analysis of the Canadian Oil Sands Experience

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2013-09-01

    For those who support U.S. oil sands development, the Canadian oil sands industry is often identified as a model the U.S. might emulate, yielding financial and energy security benefits. For opponents of domestic oil sands development, the Canadian oil sands experience illustrates the risks that opponents of development believe should deter domestic policymakers from incenting U.S. oil sands development. This report does not seek to evaluate the particular underpinnings of either side of this policy argument, but rather attempts to delve into the question of whether the Canadian experience has relevance as a foundational model for U.S. oil sands development. More specifically, this report seeks to assess whether and how the Canadian oil sands experience might be predictive or instructive in the context of fashioning a framework for a U.S. oil sands industry. In evaluating the implications of these underpinnings for a prospective U.S. oil sands industry, this report concentrates on prospective development of the oil sands deposits found in Utah.

  18. Changes in active eolian sand at northern Coachella Valley, California

    Science.gov (United States)

    Katra, Itzhak; Scheidt, Stephen; Lancaster, Nicholas

    2009-04-01

    Climate variability and rapid urbanization have influenced the sand environments in the northern Coachella Valley throughout the late 20th century. This paper addresses changes in the spatial relationships among different sand deposits at northern Coachella Valley between two recent time periods by using satellite data acquired from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The approach employed here, involving multispectral thermal infrared (TIR) data and spectral mixture analysis, has shown that the major sand deposits can be spatially modeled at northern Coachella Valley. The "coarse-grained (quartz-rich) sand" deposit is associated with active eolian sand, and the "mixed sandy soil" and "fine-grained (quartz-rich) sand" deposits are associated with inactive eolian sand. The fractional abundance images showed a significant decrease between 2000 and 2006 in the percentage of active sand in the major depositional area for fluvial sediment, the Whitewater River, but also in two downwind areas: the Whitewater and Willow Hole Reserves. The pattern of the active sand appears to be related to variations in annual precipitation (wet and dry years) and river discharge in the northern Coachella Valley. We suggest here that recent human modifications to the major watercourses that supply sand affect the capability of fluvial deposition areas to restore sediments over time and consequently the responses of the sand transport system to climate change, becoming more sensitive to dry years where areas of active sand may shrink, degrade, and/or stabilize faster. The approach utilized in this study can be advantageous for future monitoring of sand in the northern Coachella Valley for management of these and similar environments.

  19. Soil arthropod fauna from natural ecosites and reclaimed oil sands soils in northern Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Battigelli, J.P.; Leskiw, L.A. [Paragon Soil and Environmental Consulting Inc., Edmonton, AB (Canada)

    2006-07-01

    An understanding of soil invertebrates may facilitate current reclamation activities in the oil sands region of Alberta. This paper presented the results of a study investigating the density, diversity, and structure of soil arthropod assemblages in natural habitats and reclaimed sites. The purpose of the study was to establish a baseline inventory of soil arthropod assemblages in order to enable long-term monitoring of soil arthropod recolonization in disturbed sites. Nine natural ecosites were sampled for the study, including peat mix over secondary material over tailing sand; direct placement over tailing sand; peat mix over secondary over overburden; direct placement over overburden; peat mix over tailing sand; and peat mix over overburden. Samples were collected from previously established long-term soil and vegetation treatment plots in both natural ecosites and reclaimed soil sites located near Fort McMurray, Alberta. Results showed that densities of mesofauna were significantly higher in samples collected from natural ecosites. Acari and Collembola represented approximately 97 to 98 per cent of the fauna collected. It was also noted that the overall structure of the soil mesofauna community differed between natural soils and reclaimed soils. A significant reduction in the abundance of oribatid mites was observed in soils that had been reclaimed for over 34 years. Changes in the soil mesofauna community structure suggested that reclaimed soils continue to represent disturbed ecosites, as was indicated by higher proportions of prostigmatid mites and some collembolan families. Differences in community structure may influence soil ecosystem functions, including decomposition rates; nutrient recycling; soil structure; and fungal and bacterial biomass. It was concluded that further research is needed to examine oribatid mites and collembolan species diversity and community structure in reclaimed soils. 18 refs., 6 figs.

  20. Study on natural breeding sites of sand flies (Diptera: Phlebotominae) in areas of Leishmania transmission in Colombia.

    Science.gov (United States)

    Vivero, Rafael José; Torres-Gutierrez, Carolina; Bejarano, Eduar E; Peña, Horacio Cadena; Estrada, Luis Gregorio; Florez, Fernando; Ortega, Edgar; Aparicio, Yamileth; Muskus, Carlos E

    2015-02-22

    The location of the microhabitats where immature phlebotomine sand flies of the genus Lutzomyia develop is one of the least-known aspects of this group of medically important insects. For this reason strategies of source reduction approach for their control have not been possible in contrast to other insect vectors (such as mosquitoes), because their juvenile stages in terrestrial microhabitats is difficult to detect. Direct examination of soil samples, incubation of substrates and the use of emergence traps were the methods used to identify juvenile stages in 160 soil samples from urban and forest habitats within the foci of Leishmania transmission in Colombia. Immatures collected were identified subsequent from the rearing and emergence of adults using taxonomic keys or the analysis of the mitochondrial marker cytochrome oxidase I. Plant species associated with the natural breeding sites were identified and physicochemical properties of the soils were analyzed. A total of 38 (23.7%) sampling sites were identified as breeding sites, 142 phlebotomine sand flies were identified, belonging to 13 species of the genus Lutzomyia and two of Brumptomyia. The greatest numbers of immature were found within the tabular roots (51 immature sand flies from eight positive sites) and bases of trees (35 immature sand flies from 11 sites). The characterization and presence of the tree species (mainly Ceiba pentadra, Anacardium excelsum, Pseudosamanea guachapale) and the physicochemical properties (relative humidity and carbon/nitrogen ratio) of the soils associated with these breeding sites are significant factors in explaining the diversity and abundance of phlebotomine sand flies. Immature phlebotomine sand flies of the genus Lutzomyia in Colombia can be found in a wide variety of breeding sites rich in organic matter, high relative humidity and are associated with a typical vegetation of each locality. These results provide new perspectives for the study of the ecology of the

  1. Using vegetation structure estimates derived from multi-source remote sensing to predict dynamics of a semi-arid ecosystem in the western US

    Science.gov (United States)

    Shrestha, R.; Mitchell, J. J.; Glenn, N. F.; Flores, A. N.

    2014-12-01

    The distribution of species and vegetation types across the western US are expected to shift in response to climate change. Previous studies have documented the change in fire regime and the increasing fire-invasive grass cycle occurring in the western U.S. The change in vegetation structure due to climate change and invasive species alters the fuel load, making these ecosystems vulnerable to high-severity fire. Synergistic remote sensing data, such as hyperspectral data and high-resolution lidar, can be leveraged to capture the composition and structural variability of short-statured semiarid vegetation (e.g. sagebrush, annual grasses). We use a random-forests based fusion technique to integrate multi-source airborne data (hyperspectral and LiDAR) and generate spatially-explicit estimates of vegetation composition and structure (biomass, cover, density, height, LAI) and associated uncertainty across a climate and elevation gradient in southern Idaho. The results will be used to initialize an individual-based terrestrial biosphere model (Ecosystem Demography, ED2) and estimate structural dynamics under future scenarios. This study will provide a basis for understanding feedback mechanisms related to changing climate conditions, fire regimes and patterns of non-native plant invasion. The forthcoming field and remote sensing collection campaigns are also designed for parameterizing a dryland shrub plant functional type in the ED2 model.

  2. Asian interests in Alberta oil sands

    International Nuclear Information System (INIS)

    Du Plessis, D.; Laureshen, C.

    2004-01-01

    The growing Asian interest in Alberta's oil sands and import opportunities was discussed along with the feasibility of marketing bitumen to Asia. Asia is an obvious new market for Canadian heavy oil and bitumen due to an increasing demand for petroleum products in Japan, Korea, Taiwan and China. This paper examined the following three criteria that will determine the success of any initiative to move Canadian crude oil to Asian-Pacific markets: (1) a sustainable supply from Alberta; a pipeline to transport the crude to a deepwater port on the west coast; and, a guaranteed market at the other end. The basis for Asian interest in Alberta's oil sands is the sustainable secure supply of oil for growing Asian markets; heavy dependence on supplies from the Middle East; the desire to diversify supply sources; and, opportunities to invest in oil sands developments. Examples of Asian (Japan, Korea, Taiwan and China) missions to Alberta were presented along with the challenges of getting products to market with reference to Enbridge's new market access plan, Terasen's staged capacity expansion for heavy crudes and refined products, and sea transport from Prince Rupert. The paper also included graphs depicting world GDP; incremental increase in world primary energy demand by fuel for 2000 to 2020; world oil demand by region; oil demand by region in Asia; oil demand and supply in northeast Asia (Japan, China, Korea) and dependence level on Middle Eastern oil; oil demand and supply in China; China's petroleum production and consumption; refined products market forecast for 2000 to 2020; 2002 crude oil imports to Asia; 2004 refining capacity; product quality comparisons; cost competitive study; and energy policy objectives for China, Japan, Korea and Taiwan. 19 figs

  3. Western Gas Sands Project status report

    Energy Technology Data Exchange (ETDEWEB)

    Atkinson, C.H.

    1978-11-30

    Progress of government-sponsored projects directed toward increasing gas production from the low-permeability gas sands of the western United States is summarized. A Technology Implementation Plan (TIP) meeting was held at the CER office in Las Vegas, Nevada, October 16--19 to initiate the implementation phase of the Enhanced Gas Recovery (EGR) working group activities. A WGSP Logging Program meeting was conducted on October 24, 1978, at CER offices to define the problems associated with logs in tight gas sands. CER personnel and the project manager attended a two-day course on the fundamentals of core and reservoir analysis in Denver, Colorado, and met with USGS personnel to discuss USGS work on the WGSP. A meeting was held to discuss a contract for coring a Twin Arrow well on the Douglas Creek Arch, Colorado. CER Corporation personnel attended the Geological Society of America Annual Meeting held in Toronto, Canada, October 23--27 and a Gas Stimulation Workshop at Sandia Laboratories in Albuquerque, New Mexico, October 11 and 12 to discuss recent mineback experiments conducted at the Nevada Test Site. Fiscal year 1979 projects initiated by USGS and the Energy Technology Centers and National Laboratories are progressing as scheduled. Mobil Research and Development Corporation fractured zone 8 of the F-31-13G well in Rio Blanco County, Colorado. Colorado Interstate Gas Company poured the concrete pad for the compresser expected to be delivered in December and were laying pipeline between the wells at month end. The Mitchell Energy well, Muse Duke No. 1 was flowing on test at a rate of 2,100 Mcfd and preparations proceeded to fracture the well on November 15 with approximately 1,000,000 gal of fluid and 3,000,000 lb of sand. Terra Tek completed laboratory analyses of cores taken from the Mitchell Energy well.

  4. Radiogenic heavy minerals in Brazilian beach sand

    International Nuclear Information System (INIS)

    Malanca, A.

    1998-01-01

    Sand samples collected on the beaches of the 'radioactive' Brazilian town of Guarapari were first separated by flotation in bromoform and successively divided into various magnetic fractions with a Franz isodynamic separator. concentrations of background radionuclides in samples of monazite, ilmenite, and zircon were determined by a γ-ray spectrometer. Chemical composition of monazite, ilmenite and magnetite were assessed by means of an electron microprobe. Monazite resulted to be relatively rich in ThO 2 whose abundance ranged from 5.3 to 7.7 (wt%). (author)

  5. Limitation of releases and filtration by sand

    International Nuclear Information System (INIS)

    Schektman, N.

    1986-01-01

    In the highly hypothetic case of a severe reactor accident, it may lead to an increase of pressure within the containment and up to a value above the calculated pressure. A procedure is necessary in this case to maintain the integrity of the containment to prevent a release of radioactive products to the environment, while controlling in the best way releases. So, EDF and the CEA have developed a device of decompression-filtration of the containment atmosphere, using a free penetration of the containment and a sand box; the device and its operation constitute the U5 procedure [fr

  6. Sphere impact and penetration into wet sand

    KAUST Repository

    Marston, J. O.

    2012-08-07

    We present experimental results for the penetration of a solid sphere when released onto wet sand. We show, by measuring the final penetration depth, that the cohesion induced by the water can result in either a deeper or shallower penetration for a given release height compared to dry granular material. Thus the presence of water can either lubricate or stiffen the granular material. By assuming the shear rate is proportional to the impact velocity and using the depth-averaged stopping force in calculating the shear stress, we derive effective viscosities for the wet granular materials.

  7. Prolífica George Sand

    Directory of Open Access Journals (Sweden)

    Àngels Santa

    2014-04-01

    Full Text Available A propósito de las obras de George Sand, Œuvres complètes. Sous la direction de Béatrice Didier. 1841-1842.Un hiver à Majorque. Édition critique par Angela Ryan. Horace.Édition critique par Jeanne Brunereau (París, Honoré Champion, 2013, 748 p. ISBN : 9782745319265 y Œuvres complètes. ́Sous la direction de Béatrice Didier. 1849.La petite Fadette. Édition critique par Andrée Mansau (París, Honoré Champion, 2013, 345p. ISBN : 9782745319203

  8. Investigation of Sand-Cement Grouts

    Science.gov (United States)

    1960-09-01

    I -IEN NO Isis Table 1 InvestiiatLon of Sand-Cement Crouts Data on Lhe Physical Properties of the inely Divided Mineral Admixt)res Blaine Specific...Itoi, tuicrlt.nel, Caiftrnia; fl1; aish, Illinois; ;1iaricito, California; Lo’ss, Yisniasi~pi; bentornitoe, Wy~caing. Physical drnta for the raateriais...increase i’: tne a.cunt of .anj th-?t coul be puiped. As the diatomite had a specific ,i’face about 1C tines that of the loe33, it would appear that this

  9. SandBlaster: Reversing the Apple Sandbox

    OpenAIRE

    Deaconescu, Răzvan; Deshotels, Luke; Bucicoiu, Mihai; Enck, William; Davi, Lucas; Sadeghi, Ahmad-Reza

    2016-01-01

    In order to limit the damage of malware on Mac OS X and iOS, Apple uses sandboxing, a kernel-level security layer that provides tight constraints for system calls. Particularly used for Apple iOS, sandboxing prevents apps from executing potentially dangerous actions, by defining rules in a sandbox profile. Investigating Apple's built-in sandbox profiles is difficult as they are compiled and stored in binary format. We present SandBlaster, a software bundle that is able to reverse/decompile Ap...

  10. Heating tar sands formations while controlling pressure

    Science.gov (United States)

    Stegemeier, George Leo [Houston, TX; Beer, Gary Lee [Houston, TX; Zhang, Etuan [Houston, TX

    2010-01-12

    Methods for treating a tar sands formation are described herein. Methods may include heating at least a section of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. A pressure in the majority of the section may be maintained below a fracture pressure of the formation. The pressure in the majority of the section may be reduced to a selected pressure after the average temperature reaches a temperature that is above 240.degree. C. and is at or below pyrolysis temperatures of hydrocarbons in the section. At least some hydrocarbon fluids may be produced from the formation.

  11. Heating tar sands formations to visbreaking temperatures

    Science.gov (United States)

    Karanikas, John Michael [Houston, TX; Colmenares, Tulio Rafael [Houston, TX; Zhang, Etuan [Houston, TX; Marino, Marian [Houston, TX; Roes, Augustinus Wilhelmus Maria [Houston, TX; Ryan, Robert Charles [Houston, TX; Beer, Gary Lee [Houston, TX; Dombrowski, Robert James [Houston, TX; Jaiswal, Namit [Houston, TX

    2009-12-22

    Methods for treating a tar sands formation are described herein. Methods may include heating at least a section of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. The heat may be controlled so that at least a majority of the section reaches an average temperature of between 200.degree. C. and 240.degree. C., which results in visbreaking of at least some hydrocarbons in the section. At least some visbroken hydrocarbon fluids may be produced from the formation.

  12. Sphere impact and penetration into wet sand

    KAUST Repository

    Marston, J. O.; Vakarelski, Ivan Uriev; Thoroddsen, Sigurdur T

    2012-01-01

    We present experimental results for the penetration of a solid sphere when released onto wet sand. We show, by measuring the final penetration depth, that the cohesion induced by the water can result in either a deeper or shallower penetration for a given release height compared to dry granular material. Thus the presence of water can either lubricate or stiffen the granular material. By assuming the shear rate is proportional to the impact velocity and using the depth-averaged stopping force in calculating the shear stress, we derive effective viscosities for the wet granular materials.

  13. A comparison of seed banks across a sand dune successional gradient at Lake Michigan dunes (Indiana, USA)

    Science.gov (United States)

    Leicht-Young, S. A.; Pavlovic, N.B.; Grundel, R.; Frohnapple, K.J.

    2009-01-01

    In habitats where disturbance is frequent, seed banks are important for the regeneration of vegetation. Sand dune systems are dynamic habitats in which sand movement provides intermittent disturbance. As succession proceeds from bare sand to forest, the disturbance decreases. At Indiana Dunes National Lakeshore, we examined the seed banks of three habitat types across a successional gradient: foredunes, secondary dunes, and oak savanna. There were differences among the types of species that germinated from each of the habitats. The mean seed bank density increased across the successional gradient by habitat, from 376 to 433 to 968 seeds m-2, but with foredune and secondary dune seed bank densities being significantly lower than the savanna seed bank density. The number of seeds germinated was significantly correlated with soil organic carbon, demonstrating for this primary successional sequence that seed density increases with stage and age. The seed bank had much lower species richness than that of the aboveground vegetation across all habitats. Among sites within a habitat type, the similarity of species germinated from the seed banks was very low, illustrating the variability of the seed bank even in similar habitat types. These results suggest that restoration of these habitats cannot rely on seed banks alone. ?? 2008 Springer Science+Business Media B.V.

  14. The Vegetables Turned:

    DEFF Research Database (Denmark)

    Carter, Dale

    2009-01-01

    in the relationship between creative artists and the Anglo-American popular music industry in the mid-1960s. Finally, and in retrospect, the figure of the vegetable cast into relief the counter-culture's utopian and dystopian dynamics as manifested in these song-writers' personal lives, now rendered as contemporary...... lyricist Van Dyke Parks, the incongruous, semantically complex figure of the vegetable came to illuminate aspects of psychedelic consciousness and - part by design, part by accident - the link between LSD and Anglo-American popular music. It threw light, too, on the scope and limits of changes...

  15. Estimating vegetation biomass and cover across large plots in shrub and grass dominated drylands using terrestrial lidar and machine learning

    Science.gov (United States)

    Anderson, Kyle E.; Glenn, Nancy F.; Spaete, Lucas P.; Shinneman, Douglas; Pilliod, David S.; Arkle, Robert; McIlroy, Susan; Derryberry, DeWayne R.

    2018-01-01

    Terrestrial laser scanning (TLS) has been shown to enable an efficient, precise, and non-destructive inventory of vegetation structure at ranges up to hundreds of meters. We developed a method that leverages TLS collections with machine learning techniques to model and map canopy cover and biomass of several classes of short-stature vegetation across large plots. We collected high-definition TLS scans of 26 1-ha plots in desert grasslands and big sagebrush shrublands in southwest Idaho, USA. We used the Random Forests machine learning algorithm to develop decision tree models predicting the biomass and canopy cover of several vegetation classes from statistical descriptors of the aboveground heights of TLS points. Manual measurements of vegetation characteristics collected within each plot served as training and validation data. Models based on five or fewer TLS descriptors of vegetation heights were developed to predict the canopy cover fraction of shrubs (R2 = 0.77, RMSE = 7%), annual grasses (R2 = 0.70, RMSE = 21%), perennial grasses (R2 = 0.36, RMSE = 12%), forbs (R2 = 0.52, RMSE = 6%), bare earth or litter (R2 = 0.49, RMSE = 19%), and the biomass of shrubs (R2 = 0.71, RMSE = 175 g) and herbaceous vegetation (R2 = 0.61, RMSE = 99 g) (all values reported are out-of-bag). Our models explained much of the variability between predictions and manual measurements, and yet we expect that future applications could produce even better results by reducing some of the methodological sources of error that we encountered. Our work demonstrates how TLS can be used efficiently to extend manual measurement of vegetation characteristics from small to large plots in grasslands and shrublands, with potential application to other similarly structured ecosystems. Our method shows that vegetation structural characteristics can be modeled without classifying and delineating individual plants, a challenging and time-consuming step common in previous

  16. Assessment of sand quality on concrete performance : examination of acidic and sulfate/sulfide-bearing sands.

    Science.gov (United States)

    2014-12-01

    The purpose of this research is to examine how the presence of sulfide- and sulfate-containing : minerals in acidic aggregates may affect the properties of mortar and concrete. Analyses were : performed to compare two sands from a deposit in the Geor...

  17. Oil sands to the rescue: oil sand microbial communities can degrade recalcitrant alkyl phenyl alkanoic acids

    Energy Technology Data Exchange (ETDEWEB)

    Whitby, Corinne [University of Essex (Canada)], email: cwhitby@essex.ac.uk

    2011-07-01

    Almost half of all global oil reserves are found as biodegraded heavy oils found in vast tar sand deposits located in North and South America and these account for 47% of Canadian oil production. Oil sand extraction generates large amounts of toxic waste water, known as oil sand process waters (OSPW), that are stored in large tailing ponds that contain toxic compounds like naphthenic acids (NAs). The presence of NAs creates problems like toxicity, corrosion, and the formation of calcium napthenate deposits which block pipelines and other infrastructure and need to be removed. This paper presents oil sand microbial communities that can degrade these NAs. The approach is to apply new aliphatic and aromatic NAs as substrates to supplement and identify NA degrading microbes and also to identify the metabolites produced and explain NA degradation pathways and the functional genes involved. The chemistry and the processes involved are explained. From the results, it is suggested that pure cultures of P. putida KT2440 be used against NAs.

  18. The stable stiffness triangle - drained sand during deformation cycles

    DEFF Research Database (Denmark)

    Sabaliauskas, Tomas; Ibsen, Lars Bo

    2017-01-01

    Cyclic, drained sand stiffness was observed using the Danish triaxial appa- ratus. New, deformation dependant soil property (the stable stiffness triangle) was detected. Using the the stable stiffness triangle, secant stiffness of drained sand was plausible to predict (and control) even during ir...... findings can find application in off-shore, seismic and other engi- neering practice, or inspire new branches of research and modelling wherever dynamic, cyclic or transient loaded sand is encountered....

  19. Evaluation of sand reserves in del Plata City

    International Nuclear Information System (INIS)

    Loureiro, J.

    2014-01-01

    The purpose of this study is to evaluate the reserve of sand in the zone of del Plata city and beyond. This area is located in the S E edge of the department of San Jose near the mouth of Santa Lucia river. In this zone was identified the mantle of potentially exploitable sand which are based on their particle size, composition and depth of the limits cape. There are two powerful capes of sand separated by clay and silt

  20. Final report on Thermally Modified Sand demonstration project

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-23

    The use of salt and salt/sand mixtures on icy roadway surfaces has dramatically increased during the past 30 years. Despite extensive documentation on salt related damage to the roadway improvements, vehicles and the environment, road maintenance departments have continued to rely on this practice. Road maintenance departments in northern climate areas have long recognized the safety benefits for public mobility on icy roadways from the use of sand. As an abrasive material, the sand improves the surface traction that results in more drivable and less hazardous road conditions during the winter months. Stockpiles of pure sand stored during the winter months oftentimes freeze into large unworkable, monolithic piles. To maintain a free-flowing condition, it has been found to be necessary to add salt to the sand. The addition of salt in amounts ranging from 5 to 10 percent to that of sand, is usually sufficient to provide relatively free-flowing abrasive material that could be stored in stockpiles and applied to icy road surfaces with conventional sand spreading trucks. Another alternative for winter storage of pure sand to maintain a free-flowing condition is in humidity-controlled, heated buildings. As would be expected, this method has high capital and operating costs. and not cost effective for general highway maintenance use. The invention demonstrated herein is a method of thermally modifying pure sand that will remain in a free-flowing state throughout the winter season without the need for the salt additive. The thermally modified sand provides an abrasive material that when applied to icy roads does not cause environmental and corrosive damage as done by the application of sand with salt. By employing a very simple process of freezing screened sand particles by forced air convection under subfreezing conditions, the invention creates a product that has significant value in terms of economic and environmental benefits.

  1. Relationships between sand and water quality at recreational beaches.

    Science.gov (United States)

    Phillips, Matthew C; Solo-Gabriele, Helena M; Piggot, Alan M; Klaus, James S; Zhang, Yifan

    2011-12-15

    Enterococci are used to assess the risk of negative human health impacts from recreational waters. Studies have shown sustained populations of enterococci within sediments of beaches but comprehensive surveys of multiple tidal zones on beaches in a regional area and their relationship to beach management decisions are limited. We sampled three tidal zones on eight South Florida beaches in Miami-Dade and Broward counties and found that enterococci were ubiquitous within South Florida beach sands although their levels varied greatly both among the beaches and between the supratidal, intertidal and subtidal zones. The supratidal sands consistently had significantly higher (p sand) than the other two zones. Levels of enterococci within the subtidal sand correlated with the average level of enterococci in the water (CFU/100mL) for the season during which samples were collected (r(s) = 0.73). The average sand enterococci content over all the zones on each beach correlated with the average water enterococci levels of the year prior to sand samplings (r(s) = 0.64) as well as the average water enterococci levels for the month after sand samplings (r(s) = 0.54). Results indicate a connection between levels of enterococci in beach water and sands throughout South Florida's beaches and suggest that the sands are one of the predominant reservoirs of enterococci impacting beach water quality. As a result, beaches with lower levels of enterococci in the sand had fewer exceedences relative to beaches with higher levels of sand enterococci. More research should focus on evaluating beach sand quality as a means to predict and regulate marine recreational water quality. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Evaluation of Augmented REality Sandtable (ARES) during Sand Table Construction

    Science.gov (United States)

    2018-01-01

    sand table, ARES, resulted in significantly higher- quality ratings overall for the terrain model based on a global rating scale, as well as...dependent measures in this study. Sand Table Construction Score Card: A 5-point Likert scale was used to identify the accuracy and quality of required...reproduced on the sand table. The quality of the map reproduced was evaluated using standard procedures of the map-drawing paradigm, such as that

  3. White Sands, New Mexico as seen from STS-60

    Science.gov (United States)

    1994-01-01

    White Sands National Monument (Park) is easily recognized in the center of this near-vertical color photograph. White Sands is the world's largest gypsum dune field. It represents an alabaster sea that covers nearly 300 square miles. At the southwest corner of the White Sands is dry lake, Lucero. In terms of cultural features the city of Alamogordo and Holloman Air Force Base can be seen with great clarity on this photograph.

  4. Effects of feral free-roaming horses on semi-arid rangeland ecosystems: an example from the sagebrush steppe

    Science.gov (United States)

    Feral horses (Equus caballus) are viewed as a symbol of freedom and power; however, they are also a largely unmanaged, non-native grazer in North America, South America, and Australia. Information on their influence on vegetation and soil characteristics in semi-arid rangelands has been limited by ...

  5. Production and global transport of Titan's sand particles

    Science.gov (United States)

    Barnes, Jason W.; Lorenz, Ralph D.; Radebaugh, Jani; Hayes, Alexander G.; Arnold, Karl; Chandler, Clayton

    2015-06-01

    Previous authors have suggested that Titan's individual sand particles form by either sintering or by lithification and erosion. We suggest two new mechanisms for the production of Titan's organic sand particles that would occur within bodies of liquid: flocculation and evaporitic precipitation. Such production mechanisms would suggest discrete sand sources in dry lakebeds. We search for such sources, but find no convincing candidates with the present Cassini Visual and Infrared Mapping Spectrometer coverage. As a result we propose that Titan's equatorial dunes may represent a single, global sand sea with west-to-east transport providing sources and sinks for sand in each interconnected basin. The sand might then be transported around Xanadu by fast-moving Barchan dune chains and/or fluvial transport in transient riverbeds. A river at the Xanadu/Shangri-La border could explain the sharp edge of the sand sea there, much like the Kuiseb River stops the Namib Sand Sea in southwest Africa on Earth. Future missions could use the composition of Titan's sands to constrain the global hydrocarbon cycle.

  6. Trajectories of saltating sand particles behind a porous fence

    Science.gov (United States)

    Zhang, Ning; Lee, Sang Joon; Chen, Ting-Guo

    2015-01-01

    Trajectories of aeolian sand particles behind a porous wind fence embedded in a simulated atmospheric boundary layer were visualized experimentally, to investigate the shelter effect of the fence on sand saltation. Two sand samples, one collected from a beach (d = 250 μm) and the other from a desert (d = 100 μm), were tested in comparison with the previous studies of a 'no-fence' case. A wind fence (ε = 38.5%) was installed on a flat sand bed filled with each sand sample. A high-speed photography technique and the particle tracking velocimetry (PTV) method were employed to reconstruct the trajectories of particles saltating behind the fence. The collision processes of these sand particles were analyzed, momentum and kinetic energy transfer between saltating particles and ground surface were also investigated. In the wake region, probability density distributions of the impact velocities agree well with the pattern of no-fence case, and can be explained by a log-normal law. The horizontal component of impact velocity for the beach sand is decreased by about 54%, and about 76% for the desert sand. Vertical restitution coefficients of bouncing particles are smaller than 1.0 due to the presence of the wind fence. The saltating particles lose a large proportion of their energy during the collision process. These results illustrate that the porous wind fence effectively abates the further evolution of saltating sand particles.

  7. Numerical simulation of flow and compression of green sand

    DEFF Research Database (Denmark)

    Hovad, Emil

    The focus of the industrial PhD project was concentrated on the production of the sand mold (green sand) which gives the cast component its final geometrical shape. In order to ensure a high quality of the cast component, it is important to control the manufacturing process of the mold itself so...... that it is homogeneous and stable. Therefore gaining a basic understanding of how the flow and deposition of green sand should be characterized and modelled was important, so that it could be used for simulation of the manufacturing process of the sand mold. The flowability of the green sand is important when the sand...... flows down through the hopper filling the chamber with sand during the sand shot. The flowability of green sand is mostly governed by the amount of water and bentonite which both decrease it. The flowability and the internal forces thus control how well you can fill a complex mold geom-etry in which...

  8. An investigation of waste foundry sand in asphalt concrete mixtures.

    Science.gov (United States)

    Bakis, Recep; Koyuncu, Hakan; Demirbas, Ayhan

    2006-06-01

    A laboratory study regarding the reuse of waste foundry sand in asphalt concrete production by replacing a certain portion of aggregate with WFS was undertaken. The results showed that replacement of 10% aggregates with waste foundry sand was found to be the most suitable for asphalt concrete mixtures. Furthermore, the chemical and physical properties of waste foundry sand were analysed in the laboratory to determine the potential effect on the environment. The results indicated that the investigated waste foundry sand did not significantly affect the environment around the deposition

  9. Effective Laboratory Method of Chromite Content Estimation in Reclaimed Sands

    Directory of Open Access Journals (Sweden)

    Ignaszak Z.

    2016-09-01

    Full Text Available The paper presents an original method of measuring the actual chromite content in the circulating moulding sand of foundry. This type of material is applied for production of moulds. This is the case of foundry which most frequently perform heavy casting in which for the construction of chemical hardening mould is used, both the quartz sand and chromite sand. After the dry reclamation of used moulding sand, both types of sands are mixed in various ratios resulting that in reclaimed sand silos, the layers of varying content of chromite in mixture are observed. For chromite recuperation from the circulating moulding sand there are applied the appropriate installations equipped with separate elements generating locally strong magnetic field. The knowledge of the current ratio of chromite and quartz sand allows to optimize the settings of installation and control of the separation efficiency. The arduous and time-consuming method of determining the content of chromite using bromoform liquid requires operational powers and precautions during using this toxic liquid. It was developed and tested the new, uncomplicated gravimetric laboratory method using powerful permanent magnets (neodymium. The method is used in the production conditions of casting for current inspection of chromite quantity in used sand in reclamation plant.

  10. Reuse of waste cutting sand at Lawrence Livermore National Laboratory

    International Nuclear Information System (INIS)

    Mathews, S.; Wilson, K.

    1998-01-01

    Lawrence Livermore National Laboratory (LLNL) examined the waste stream from a water jet cutting operation, to evaluate the possible reuse of waste garnet sand. The sand is a cutting agent used to shape a variety of materials, including metals. Nearly 70,000 pounds of waste sand is generated annually by the cutting operation. The Environmental Protection Department evaluated two potential reuses for the spent garnet sand: backfill in utility trenches; and as a concrete constituent. In both applications, garnet waste would replace the sand formerly purchased by LLNL for these purposes. Findings supported the reuse of waste garnet sand in concrete, but disqualified its proposed application as trench backfill. Waste sand stabilized in a concrete matrix appeared to present no metals-leaching hazard; however, unconsolidated sand in trenches could potentially leach metals in concentrations high enough to threaten ground water quality. A technical report submitted to the San Francisco Bay Regional Water Quality Control Board was reviewed and accepted by that body. Reuse of waste garnet cutting sand as a constituent in concrete poured to form walkways and patios at LLNL was approved

  11. Quantifying the effects of European beach grass on aeolian sand transport over the last century: Bodega Marine Reserve, California

    Science.gov (United States)

    Cesmat, R.; Werner, S.; Smith, M. E.; Riedel, T.; Best, R.; Olyarnik, S.

    2012-12-01

    Introduction of European beach grass (Ammophila arenaria) to coastal dune systems of western North America induced significant changes to the transport and storage of sediment, and consequently the nesting habitat of the western snowy plover (Charadrius alexandrinus nivosus). At the Bodega Marine Reserve and Sonoma Coast State Park, Ammophila was introduced within the ~0.5 km2 dune area in the 1920's to limit the flux of sand through Bodega Harbor and agricultural land. To assess the potential impact of restoration efforts (Ammophila removal) on aeolian sediment flux, we measured sediment flux as a function of wind speeds and ground cover, and used these measurements to parameterize a spatial model for historical sand deposition Fine- to coarse-grained lithic to sub-lithic sand is delivered to the Bodega dune system from Salmon Creek beach, the down-shore terminus of a littoral system fed by the 3846 km2 Russian River catchment, several small (Gaffney ridge) at the edge of the planted region. An average accumulation rate of ~4,000 m3/yr is indicated within the study swath by the preserved sediment volumes. Within the modern dune system, unvegetated areas exhibit 2-3 meter wavelength, ~1/2 meter amplitude mega-ripples, and the uppermost 2-10 cm consists of coarse-sand to granule-sized armor layer. In contrast, grain-sizes in vegetated areas are largely vertically homogenous. Open areas are typically 2-8 meters lower than adjacent vegetated areas, and show evidence for net lowering of the land surface (i.e., exposed fence posts, roots). Conversely, vegetated areas appear prone to sediment accumulation, particularly downwind of unvegetated areas. We measured sand transport using 0.5 m high traps deployed at 18 sites throughout the dune field, and used a linear mixed effects model to predict transport rate as a function of wind and ground cover class, taking into account random effects of sampling date and repeated measurements at each site. The analysis indicates up

  12. Mineral legislations applicable to beach sand industry

    International Nuclear Information System (INIS)

    D'Cruz, Eric

    2016-01-01

    India has got a wealth of natural resources in different geological environs and shoreline placers form an important constituent of the natural resources. Large reserves of beach sand minerals, viz. imenite, rutile, leucoxene, zircon, sillimanite, garnet and monazite are the economic minerals in the coastal and inland placer sands. In the federal structure of India, the State Governments are the owners of minerals located within their respective boundaries. The State Governments grant the mineral concessions for all the minerals located within the boundary of the State, under the provisions of the Acts and Rules framed for the purpose. Though the mineral wealth is under the control of the State, the power for framing the rules for the grant of mineral concessions vastly rest with the Central Government. Since mineral concessions are often granted for a longer duration of thirty to fifty years or more, a historical perspective of these rules are imperative in understanding the issues involved with BSM mining industry. Under the Govt. of India Act, 1935, Regulation of Mines and Oilfields and Mineral Development was kept under Federal control, declared by Federal Law. The word 'Federal' was substituted by the word 'Dominion' by the India (Provincial Constitution) Order, 1947. No legislation was, however, enacted in pursuance of above power until after Independence. However, the Govt. on India made the Mining Concession (Central) Rules, 1939 for regulating grants of prospecting license

  13. Integrated oil sands tailings pond water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Z. [Saskatchewan Research Council, Saskatoon, SK (Canada)

    2010-07-01

    This PowerPoint presentation discussed research currently being conducted to treat oil sands tailings pond water (TPW). The treatment of TPW is challenged by the high level of naphthenic acids (NAs), the slow settling rate of fine particulate materials, and the complex chemistry of the water. The treatment process consisted of bioflocculation, sludge blanket assisted clarification, ozonation, and oil sands coke assisted hybrid biodegradation. The aggregation and adsorption process bound small particles and cells together while also ensuring the passive uptake of pollutants using microbial masses. The mixed liquor then passed through a sludge blanket to ensure enhanced particle capture. An ozonation process was used to increase the biodegradability of the TPW as well as to increase the biodegradability of the residual NAs after ozonation. The process used a hybrid bioreactor that consisted of both suspended and fixed microbial communities. The coke served as a biofilm carrier for the waste. Further studies are being conducted to investigate the efficiency and capability of the process. tabs., figs.

  14. Avalanches of Singing Sand in the Laboratory

    Science.gov (United States)

    Dagois-Bohy, Simon; Courrech Du Pont, Sylvain; Douady, Stéphane

    2011-03-01

    The song of dunes is a natural phenomenon that has arisen travellers' curiosity for a long time, from Marco Polo to R.A. Bagnold. Scientific observations in the XXth century have shown that the sound is emitted during a shear flow of these particular grains, the free surface of the flow having coherent vibrations like a loud speaker. The sound emission is also submitted to a threshold effect with many parameters like humidity, flow speed, surface of the grains. The sound has been reproduced in laboratory avalanche experiments close to the natural phenomenon on field, but set in a channel with a hard bottom and a few centimeters of sand flowing, which contradicts explanations of the sound that involve a sand dune under the avalanche flow. Flow rates measurements also show the presence of a plug region in the flow above the sheared band, with the same characteristic length as the coherence zones of the sound. Finally we show experimentally that the Froude number, once modified to take into account the height of this plug band, is the parameter that sets the amplitude of the sound, and produces a threshold that depends on the grain type.

  15. Soil mixing of stratified contaminated sands.

    Science.gov (United States)

    Al-Tabba, A; Ayotamuno, M J; Martin, R J

    2000-02-01

    Validation of soil mixing for the treatment of contaminated ground is needed in a wide range of site conditions to widen the application of the technology and to understand the mechanisms involved. Since very limited work has been carried out in heterogeneous ground conditions, this paper investigates the effectiveness of soil mixing in stratified sands using laboratory-scale augers. This enabled a low cost investigation of factors such as grout type and form, auger design, installation procedure, mixing mode, curing period, thickness of soil layers and natural moisture content on the unconfined compressive strength, leachability and leachate pH of the soil-grout mixes. The results showed that the auger design plays a very important part in the mixing process in heterogeneous sands. The variability of the properties measured in the stratified soils and the measurable variations caused by the various factors considered, highlighted the importance of duplicating appropriate in situ conditions, the usefulness of laboratory-scale modelling of in situ conditions and the importance of modelling soil and contaminant heterogeneities at the treatability study stage.

  16. [Imperial Oil's Cold Lake oil sands operations

    International Nuclear Information System (INIS)

    Dingle, H. B.

    1999-01-01

    Imperial Oil Limited's Cold Lake oil sands resources, production and operations in Alberta are discussed. Cold Lake is the company's largest single asset and its largest source of crude oil production. In 1998, Cold Lake accounted for just under half of Imperial's total liquid production, averaging more than 135,000 barrels of bitumen a day. Despite the very difficult operating conditions experienced by the oil sands industry in 1998, Imperial Oil's Cold Lake operations generated a positive cash flow and earnings. Just as important, the near and long-term potential of Cold Lake property continues to be strong, even with the tough market conditions today and the foreseeable future. Proved reserves at the end of 1997 were 1.3 billions barrels, equal to about 24 years of current production, but even more important is Imperial's resource base in the Athabasca region, which represents 150 years of production at current rates. Although production forecasts for the near future are are revised downward because of production shut-in due to low prices, the company is confident of its long-term prospects mainly because of existing infrastructure, superior reservoir quality, 30 years worth of operating improvements and established bitumen-blend markets. Details of the company's future Cold Lake development plans are discussed. The need to continue technology development, which has been at the core of the industry's growth in the past and will continue to be the key to the future, are emphasized

  17. Enabling technologies for oil sands development

    International Nuclear Information System (INIS)

    Bailey, R.T.

    1998-01-01

    A review of oil sands production and expansion possibilities in Alberta were presented. The enabling technologies for oil sands projects include mining (bucketwheels, draglines, trucks, shovels conveyors, slurry hydrotransport); extraction (conditioning tumblers, pipelines, tanks, hot water, caustic, cold water, frothers); froth cleaning (centrifuges, solvent treatment); tailings (tailings ponds, consolidated tailings); and upgrading (coking, hydrotreating for SCO, hydrocracking and multiple products). The enabling technologies for in situ production include cyclic steam stimulation for vertical wells, steam assisted gravity drainage (SAGD) for dual horizontal wells, and cold production with wormholes. This paper described the recovery potentials of each of these processes. It also discussed the role of government and industry in research and cooperative research involving both the private and public sectors. Examples of each of these were described such as SAGD, the OSLO cold water extraction process, The consolidated tailings (CT) project, the low energy extraction process (slurry production, hydrotransport, pipeline conditioning and warm water extraction), and research in fine tailings, to demonstrate that although objectives may differ, government and industry research objectives are complementary

  18. Oil sands tailings leachability and toxicity evaluation

    International Nuclear Information System (INIS)

    Gulley, J.R.

    1995-01-01

    Fine tailings disposal and reclamation is a major issue facing the oil sands mining and extraction industry. Government regulations dictate that reclamation must return the site to a level of self-sustaining biological capability which approximates the natural condition. A two-phase laboratory program has been completed to investigate the suitability of alternative reclamation materials. For the first phase of the study, chemical and toxicological analyses were carried out on 13 different reclamation and reference materials (solid phase and extractions). Seedling emergence, nematode maturation, algal growth and bacterial luminescence for leachate samples showed a range of sensitivities in response to the tested materials, although phytotoxicity tests were generally the most sensitive. With the exception of one test material, high toxicity ratings were consistent with that expected from the chemical data. The second phase of the study focused on the evaluation of chemical and toxicological conditions in leachate water generated using bench-scale column percolation tests. Leachate water equivalent to 10 pore volume replacements was generated and temporal variations in toxicity and chemistry monitored. Similar to phase 1 findings, phytotoxicity tests were the most sensitive tests to leachate waters. For most materials tested, most toxicity was removed after 2--3 porewater replacements. More persistent toxicity was noted for samples containing bitumen (e.g., fine tails and oil sands). No clear correspondence was noted between chemical concentrations and toxicity in leachate waters

  19. Sulfur biogeochemistry of oil sands composite tailings

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Lesley; Stephenson, Kate [Earth Sciences, McMaster University (Canada)], email: warrenl@mcmaster.ca; Penner, Tara [Syncrude Environmental Research (Canada)

    2011-07-01

    This paper discusses the sulfur biogeochemistry of oil sands composite tailings (CT). The Government of Alberta is accelerating reclamation activities on composite tailings. As a CT pilot reclamation operation, Syncrude is currently constructing the first freshwater fen. Minor unpredicted incidents with H2S gas released from the dewatering process associated with these reclamations have been reported. The objective of this study is to ascertain the connection between microbial activity and H2S generation within CT and to assess the sulfur biogeochemistry of untreated and treated (fen) CT over seasonal and annual timescales. The microbial geochemical interactions taking place are shown using a flow chart. CT is composed of gypsum, sand, clay and organics like naphthenic acids and bitumen. Sulfur and Fe cycling in mining systems and their microbial activities are presented. The chemistry and the processes involved within CT are also given along with the results. It can be said that the diverse Fe and S metabolizing microorganisms confirm the ecology involved in H2S dynamics.

  20. Low enthalpy geothermal for oil sands (LEGO)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    Geothermal energy is generated by the slow decay of radioactive materials within the Earth. Geothermal energy resources include the water from hot springs used for heating; the withdrawal of high temperature steam from deep wells; and the use of stable ground or water temperatures near the Earth's surface to heat or cool buildings or in industrial processes. Heat pumps are used to transfer heat or water from the ground into buildings in winter. This paper discussed low enthalpy geothermal options for oil sands processes in order to reduce the use of natural gas and emissions from greenhouse gases (GHGs). The study was also conducted to aid in the development of a portfolio of renewable energy options for the oil and gas sector. The study estimated the costs and benefits of operating a shallow geothermal borehole cluster for meeting a portion of process heat demands for the Nexen's Albian mine. The costs and benefits of operating thermo-chillers integrated with a shallow geothermal borehole cluster for waste heat mitigation were also evaluated. The study showed that geothermal designs can be used to meet a portion of oil sands process heat and cooling demands. Mining operators may reduce carbon emissions and energy costs for process heat demands by installing closed loop borehole heat exchangers. Geothermal heat storage capacity can also be used to increase the efficiency of thermal chillers. It was concluded that pilot plant studies would contribute to a better understanding of the technology. tabs., figs.

  1. leafy vegetable, Gnetum africanum

    African Journals Online (AJOL)

    A prerequisite for successful in vitro culture is the establishment of an aseptic technique, thus the experiment was to investigate suitable sterilization regimes for the leaf explants of Gnetum africanum, an endangered green leafy vegetable. Three sterilization regimes were tested to establish the best regime using three to four ...

  2. Canopy Modeling of Aquatic Vegetation: Construction of Submerged Vegetation Index

    Science.gov (United States)

    Ma, Z.; Zhou, G.

    2018-04-01

    The unique spectral characteristics of submerged vegetation in wetlands determine that the conventional terrestrial vegetation index cannot be directly employed to species identification and parameter inversion of submerged vegetation. Based on the Aquatic Vegetation Radiative Transfer model (AVRT), this paper attempts to construct an index suitable for submerged vegetation, the model simulated data and a scene of Sentinel-2A image in Taihu Lake, China are utilized for assessing the performance of the newly constructed indices and the existent vegetation indices. The results show that the angle index composed by 525 nm, 555 nm and 670 nm can resist the effects of water columns and is more sensitive to vegetation parameters such as LAI. Furthermore, it makes a well discrimination between submerged vegetation and water bodies in the satellite data. We hope that the new index will provide a theoretical basis for future research.

  3. Science framework for the conservation and restoration strategy of DOI secretarial order 3336: Utilizing resilience and resistance concepts to assess threats to sagebrush ecosystems and greater sage-grouse, prioritize conservation and restoration actions, and inform management strategies

    Science.gov (United States)

    Chambers, Jeanne C.; Campbell, Steve; Carlson, John; Beck, Jeffrey L.; Clause, Karen J.; Dinkins, Jonathan B.; Doherty, Kevin E.; Espinosa, Shawn; Griffin, Kathleen A.; Christiansen, Thomas J.; Crist, Michele R.; Hanser, Steven E.; Havlina, Douglas W.; Henke, Kenneth F.; Hennig, Jacob D.; Kurth, Laurie L.; Maestas, Jeremy D.; Mayer, Kenneth E.; Manning, Mary E.; Mealor, Brian A.; McCarthy, Clinton; Pellant, Mike; Prentice, Karen L.; Perea, Marco A.; Pyke, David A.; Wiechman , Lief A.; Wuenschel, Amarina

    2016-01-01

    The Science Framework for the Conservation and Restoration Strategy of the Department of the Interior, Secretarial Order 3336 (SO 3336), Rangeland Fire Prevention, Management and Restoration, provides a strategic, multiscale approach for prioritizing areas for management and determining effective management strategies across the sagebrush biome. The emphasis of this version is on sagebrush ecosystems and greater sage-grouse. The Science Framework uses a six step process in which sagebrush ecosystem resilience to disturbance and resistance to nonnative, invasive annual grasses is linked to species habitat information based on the distribution and abundance of focal species. The predominant ecosystem and anthropogenic threats are assessed, and a habitat matrix is developed that helps decision makers evaluate risks and determine appropriate management strategies at regional and local scales. Areas are prioritized for management action using a geospatial approach that overlays resilience and resistance, species habitat information, and predominant threats. Decision tools are discussed for determining the suitability of priority areas for management and the most appropriate management actions at regional to local scales. The Science Framework and geospatial crosscut are intended to complement the mitigation strategies associated with the Greater Sage-Grouse Land Use Plan amendments for the Department of the Interior Bureaus, such as the Bureau of Land Management, and the U.S. Forest Service.

  4. Using resilience and resistance concepts to manage threats to sagebrush ecosystems, Gunnison sage-grouse, and Greater sage-grouse in their eastern range: A strategic multi-scale approach

    Science.gov (United States)

    Chambers, Jeanne C.; Beck, Jeffrey L.; Campbell, Steve; Carlson, John; Christiansen, Thomas J.; Clause, Karen J.; Dinkins, Jonathan B.; Doherty, Kevin E.; Griffin, Kathleen A.; Havlina, Douglas W.; Mayer, Kenneth F.; Hennig, Jacob D.; Kurth, Laurie L.; Maestas, Jeremy D.; Manning, Mary E.; Mealor, Brian A.; McCarthy, Clinton; Perea, Marco A.; Pyke, David A.

    2016-01-01

    This report provides a strategic approach developed by a Western Association of Fish and Wildlife Agencies interagency working group for conservation of sagebrush ecosystems, Greater sage-grouse, and Gunnison sage-grouse. It uses information on (1) factors that influence sagebrush ecosystem resilience to disturbance and resistance to nonnative invasive annual grasses and (2) distribution and relative abundance of sage-grouse populations to address persistent ecosystem threats, such as invasive annual grasses and wildfire, and land use and development threats, such as oil and gas development and cropland conversion, to develop effective management strategies. A sage-grouse habitat matrix links relative resilience and resistance of sagebrush ecosystems with modeled sage-grouse breeding habitat probabilities to help decisionmakers assess risks and determine appropriate management strategies at both landscape and site scales. Areas for targeted management are assessed by overlaying matrix components with Greater sage-grouse Priority Areas for Conservation and Gunnison sage-grouse critical habitat and linkages, breeding bird concentration areas, and specific habitat threats. Decision tools are discussed for determining the suitability of target areas for management and the most appropriate management actions. A similar approach was developed for the Great Basin that was incorporated into the Federal land use plan amendments and served as the basis of a Bureau of Land Management Fire and Invasives Assessment Tool, which was used to prioritize sage-grouse habitat for targeted management activities.

  5. Potensi Pasir Lokal Tanjung Bintang Pada Aluminium Sand Casting Terhadap Porositas Produk Hasil Cor Aluminium

    OpenAIRE

    Hendronursito, Yusup; Prayanda, Yogi

    2016-01-01

    Green sand is one of the most important components in the process of metal casting. The sand in Indonesia region is varied level of subtlety, size of sand, and shape of sand. Green sand used in the process of metal casting is possible can affect the quality of casting product. This aims to determine the potential of Tanjung Bintang sand as green sand and the quality of the product in terms of porosity defects. The research was conducted by varying sand river from Tanjung Bintang and sand from...

  6. Experimental Study on Superfine Sand Concrete Mixed by Double Mixing Technology

    OpenAIRE

    yuqing zhao

    2013-01-01

    Traditional concept thought that medium sand and fine sand can be used to mix concrete, superfine sand can not used to mix concrete. This makes the source of superfine sand limited. With the shortage of medium sand and fine sand, it is imperative to exploit the resource of superfine sand. Superfine sand concrete is mixed by means of Double-doped Technology-ultra-fine fly ash and super plasticizer. Primary factor influencing superfine sand concrete strength is studied by orthogonal test, the o...

  7. The use of LANDSAT-1 imagery in mapping and managing soil and range resources in the Sand Hills region of Nebraska

    Science.gov (United States)

    Seevers, P. M. (Principal Investigator); Drew, J. V.

    1976-01-01

    The author has identified the following significant results. Evaluation of ERTS-1 imagery for the Sand Hills region of Nebraska has shown that the data can be used to effectively measure several parameters of inventory needs. (1) Vegetative biomass can be estimated with a high degree of confidence using computer compatable tape data. (2) Soils can be mapped to the subgroup level with high altitude aircraft color infrared photography and to the association level with multitemporal ERTS-1 imagery. (3) Water quality in Sand Hills lakes can be estimated utilizing computer compatable tape data. (4) Center pivot irrigation can be inventoried from satellite data and can be monitored regarding site selection and relative success of establishment from high altitude aircraft color infrared photography. (5) ERTS-1 data is of exceptional value in wide-area inventory of natural resource data in the Sand Hills region of Nebraska.

  8. Review of Vegetable Market Development in China

    Institute of Scientific and Technical Information of China (English)

    Chaoping; LUO; Yuandong; NI; Qiong; ZHAI

    2013-01-01

    This paper has reviewed vegetable market development from vegetable circulation system, the develop history of the liberalize vegetable market and the growth of the vegetable wholesale market in China. From the development of vegetables market in China and its characteristics: the development of vegetable market in China is related to vegetable market system, the change of institution, some technology development and infrastructure. this paper has put forward some related measures to perfect the vegetable market and improve the vegetable circulation efficiency in China.

  9. Properties of Desert Sand and CMAS Glass

    Science.gov (United States)

    Bansal, Narottam P.; Choi, Sung R.

    2014-01-01

    As-received desert sand from a Middle East country has been characterized for its phase composition and thermal stability. X-ray diffraction analysis showed the presence of quartz (SiO2), calcite (CaCO3), gypsum (CaSO4.2H2O), and NaAlSi3O8 phases in as-received desert sand and showed weight loss of approx. 35 percent due to decomposition of CaCO3 and CaSO4.2H2O when heated to 1400 C. A batch of as-received desert sand was melted into calcium magnesium aluminosilicate (CMAS) glass at approx. 1500 C. From inductively coupled plasma-atomic emission spectrometry, chemical composition of the CMAS glass was analyzed to be 27.8CaO-4MgO-5Al2O3-61.6SiO2-0.6Fe2O3-1K2O (mole percent). Various physical, thermal and mechanical properties of the glass have been evaluated. Bulk density of CMAS glass was 2.69 g/cc, Young's modulus 92 GPa, Shear modulus 36 GPa, Poisson's ratio 0.28, dilatometric glass transition temperature (T (sub g)) 706 C, softening point (T (sub d)) 764 C, Vickers microhardness 6.3 +/- 0.4 GPa, indentation fracture toughness 0.75 +/- 0.15 MPa.m (sup 1/2), and coefficient of thermal expansion (CTE) 9.8 x 10 (exp -6)/degC in the temperature range 25 to 700 C. Temperature dependence of viscosity has also been estimated from various reference points of the CMAS glass using the Vogel-Fulcher-Tamman (VFT) equation. The glass remained amorphous after heat treating at 850 C for 10 hr but crystallized into CaSiO3 and Ca-Mg-Al silicate phases at 900 C or higher temperatures. Crystallization kinetics of the CMAS glass has also been investigated by differential thermal analysis (DTA). Activation energies for the crystallization of two different phases in the glass were calculated to be 403 and 483 kJ/mol, respectively.

  10. Cruciferous Vegetables and Cancer Prevention

    Science.gov (United States)

    ... case-control studies have found that people who ate greater amounts of cruciferous vegetables had a lower ... Professionals’ Follow-up Study—showed that women who ate more than 5 servings of cruciferous vegetables per ...

  11. Long-term sand supply to Coachella Valley Fringe-toed Lizard Habitat in the Northern Coachella Valley, California

    Science.gov (United States)

    Griffiths, Peter G.; Webb, Robert H.; Lancaster, Nicholas; Kaehler, Charles A.; Lundstrom, Scott C.

    2002-01-01

    by minimizing in-channel sediment storage on the alluvial fans. The post-development annual sediment yield to the Whitewater and Mission Creek?Morongo Wash depositional areas are 3.5 and 1.5 million ft3/yr, respectively, covering each depositional area to a depth of 0.2 to 0.4 in. Given existing sand-transport rates, this material could be depleted by eolian processes in 8 to 16 months, a rate consistent with the presence of persistent sand dunes. However, these depletion times are likely minimum estimates, as some eolian sand is seen to persist in the immediate vicinity of depositional areas for longer time periods. Transport rates may be reduced by the presence of vegetation and other windbreaks. Because they are perpendicular to prevailing winds, the infiltration galleries on Whitewater River trap fluvial and eolian sediment, reducing sediment availability. Also, the presence of the railroad and Interstate 10 redirect eolian sand movement to the southeast along their corridors,potentially eliminating the Whitewater depositional area as a sand source for the Willow Hole Reserve. Using directional wind data, we discuss the potential for eolian sand transport from the Mission Creek?Morongo Wash depositional area to Willow Hole.

  12. Vegetation morphologic and aerodynamic characteristics reduce aeolian erosion.

    Science.gov (United States)

    Miri, Abbas; Dragovich, Deirdre; Dong, Zhibao

    2017-10-09

    Vegetation cover is crucial to controlling aeolian erosion but highly efficient vegetation is critical. How this efficiency is influenced by vegetation response to airflow is not clear. Here we evaluate the responses of Cosmos bipinnatus and Ligustrum lucidum Ait to a range of wind speeds in a wind tunnel. For both species, we calculate shelter effect and sand flux. We show that plant effectiveness in reducing wind speed and sediment transport is linked to their aerodynamic response to airflow which results from their morphology. We demonstrate that in low-density cover the flow-response and resistance of individuals is most critical in the optimal effectiveness of a canopy. Our wind tunnel experiment suggests that vegetation morphology and structure must be priority parameters in facilitating aeolian erosion control.

  13. Stakeholder relations in the oil sands : managing uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-05-15

    Alberta's oil sands are now at the crossroads of a series of significant and complex global issues that will require careful negotiation by all stakeholders involved in the oil sands industry. This paper discussed methods of managing uncertainty and risk related to the oil sands industry's agenda for the future. Oil sands developers must continue to secure permission from communities and other key stakeholders in order to develop oil sand projects. Stakeholder relations between oil sands operators, First Nations, and Metis Nation communities must ensure that respect is maintained while environmental impacts are minimized and long-term economic benefits are secured for all parties. Environmental non-governmental organizations (ENGOs) must ensure that oil sands resources are developed responsibly, and that environmental standards are maintained. Seven key shifts in stakeholder relations resulting from the recent economic crisis were identified. These included (1) withdrawal from the multi-stakeholder process, (2) increased focus on government to demonstrate policy leadership, (3) a stronger push from ENGOs to express environmental concerns, (4) global lobby and public relations efforts from ENGOs, (5) companies retreating to local community stakeholders, (6) more active demands from First Nations and Metis Nations groups, and (7) companies challenging ENGO campaigns. The study concluded by suggesting that government leadership is needed to clear policy and regulatory frameworks for Canada's oil sands.

  14. On Foundation Improvement By Sand Replacement | Abam | Global ...

    African Journals Online (AJOL)

    This paper describes a simple foundation improvement method involving the replacement of poor foundation bearing soils with sand and the resultant improvement in bearing capacity and the minimization of settlement at the site of a large storage tank. Minimum thickness of sand replacement for various foundation loads ...

  15. Modeling sheet-flow sand transport under progressive surface waves

    NARCIS (Netherlands)

    Kranenburg, Wouter

    2013-01-01

    In the near-shore zone, energetic sea waves generate sheet-flow sand transport. In present day coastal models, wave-induced sheet-flow sand transport rates are usually predicted with semi-empirical transport formulas, based on extensive research on this phenomenon in oscillatory flow tunnels.

  16. Fine sand in motion: the influence of interstitial air

    NARCIS (Netherlands)

    Homan, T.A.M.

    2013-01-01

    Sand is a granular material, and therefore it consists of individual grains arranged in a packing. The pores in-between the grains are usually filled with a fluid, in this case air. Now, is this interstitial air able to influence the behavior of the sand bed as a whole? When a ball impacts on fine,

  17. Geophysical mapping of the occurrence of shallow oil sands in ...

    African Journals Online (AJOL)

    Oil sands are known to be an alternate source of energy and of great economic value. To map the occurrence of shallow oil sand deposits in Idiopopo, Okitipupa area in Ondo state southwestern Nigeria, vertical electric sounding (VES) in 11 stations along 3 profiles were carried out using the Schlumberger configuration.

  18. Sea Bed Sand Waves Studied To Help Pipeline Planners

    NARCIS (Netherlands)

    van der Mark, C.F.; de Koning, M.F.; Blom, Astrid; Hulscher, Suzanne J.M.H.; Stolk, A.

    2008-01-01

    The article cites a study that offers information on the variability of sand wave characteristics in the North Sea. The sand waves variability includes a statement that pipelines may start vibrating due to turbulence generated under the free span and navigational channels often need to be dredged

  19. Archaen to Recent aeolian sand systems and their sedimentary record

    DEFF Research Database (Denmark)

    Rodríguez-López, Juan Pedro; Clemmensen, Lars B; Lancaster, Nick

    2014-01-01

    The sedimentary record of aeolian sand systems extends from the Archean to the Quaternary, yet current understanding of aeolian sedimentary processes and product remains limited. Most preserved aeolian successions represent inland sand-sea or dunefield (erg) deposits, whereas coastal systems are ...

  20. Sand transport in urbanized beaches - models and reality

    International Nuclear Information System (INIS)

    Pineiro, G.; Norbis, W.; Panario, D.

    2012-01-01

    The general objective is to quantify the wind transport of sand in the urbanized beaches. The specific objectives include testing and calibration of the wind velocity as well as the classification of the beaches according to the magnitude and the direction of sand transport

  1. Test Setup for Axially Loaded Piles in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina

    The test setup for testing axially static and cyclic loaded piles in sand is described in the following. The purpose for the tests is to examine the tensile capacity of axially loaded piles in dense fully saturated sand. The pile dimensions are chosen to resemble full scale dimension of piles used...... in offshore pile foundations today....

  2. Beach Sand Analysis for Indicators of Microbial Contamination

    Science.gov (United States)

    Traditional beach monitoring has focused on water quality, with little attention paid to health risks associated with beach sand. Recent research has reported that fecal indicator bacteria, as well as human pathogens can be found in beach sand and may constitute a risk to human h...

  3. Effect of Crushed Sandstone Sand on the Properties of High ...

    African Journals Online (AJOL)

    This paper presents results of the laboratory investigation on high performance concrete (HPC) using crushed sandstone sand as 20%, 40%, and 60% replacement of river sand together with superplastisizer and silica fume (SF). The fresh concrete properties such as slump, air content and fresh concrete density have been ...

  4. Sediment Source Fingerprinting of the Lake Urmia Sand Dunes.

    Science.gov (United States)

    Ahmady-Birgani, Hesam; Agahi, Edris; Ahmadi, Seyed Javad; Erfanian, Mahdi

    2018-01-09

    Aeolian sand dunes are continuously being discovered in inner dry lands and coastal areas, most of which have been formed over the Last Glacial Maximum. Presently, due to some natural and anthropogenic implications on earth, newly-born sand dunes are quickly emerging. Lake Urmia, the world's second largest permanent hypersaline lake, has started shrinking, vast lands comprising sand dunes over the western shore of the lake have appeared and one question has been playing on the minds of nearby dwellers: where are these sand dunes coming from, What there was not 15 years ago!! In the present study, the determination of the source of the Lake Urmia sand dunes in terms of the quantifying relative contribution of each upstream geomorphological/lithological unit has been performed using geochemical fingerprinting techniques. The findings demonstrate that the alluvial and the fluvial sediments of the western upstream catchment have been transported by water erosion and they accumulated in the lower reaches of the Kahriz River. Wind erosion, as a secondary agent, have carried the aeolian sand-sized sediments to the sand dune area. Hence, the Lake Urmia sand dunes have been originating from simultaneous and joint actions of alluvial, fluvial and aeolian processes.

  5. Effectiveness of SCADA Systems in Control of Green Sands Properties

    Directory of Open Access Journals (Sweden)

    Ignaszak Z.

    2016-03-01

    Full Text Available The paper undertakes an important topic of evaluation of effectiveness of SCADA (Supervisory Control and Data Acquisition systems, used for monitoring and control of selected processing parameters of classic green sands used in foundry. Main focus was put on process studies of properties of so-called 1st generation molding sands in the respect of their preparation process. Possible methods of control of this processing are presented, with consideration of application of fresh raw materials, return sand (regenerate and water. The studies conducted in one of European foundries were aimed at pointing out how much application of new, automated plant of sand processing incorporating the SCADA systems allows stabilizing results of measurement of selected sand parameters after its mixing. The studies concerned two comparative periods of time, before an implementation of the automated devices for green sands processing (ASMS - Automatic Sand Measurement System and MCM – Main Control Module and after the implementation. Results of measurement of selected sand properties after implementation of the ASMS were also evaluated and compared with testing studies conducted periodically in laboratory.

  6. Pathogen removal using saturated sand colums supplemented with hydrochar

    NARCIS (Netherlands)

    Chung, J.W.

    2015-01-01

    This PhD study has evaluated hydrochars derived from biowastes as adsorbents for pathogen removal in water treatment. Pathogen removal experiments were conducted by carrying out breakthrough analysis using a simple sand filtration set-up. Glass columns packed by 10 cm sand bed supplemented with

  7. Providing floating capabilities in latest-generation sand screens

    Energy Technology Data Exchange (ETDEWEB)

    Bowen, E.G.; Coronado, M.P. [Society of Petroleum Engineers, Richardson, TX (United States)]|[Baker Hughes, Houston, TX (United States)

    2008-10-15

    Alternative production methods are needed for the massive reserves located in the bitumen region of Canada's tar sands. The area has over 100 installations of sand screens/slotted liners in both injection and production legs using steam-assisted gravity drainage (SAGD) technology. Multiple wells must be drilled from a single pad because of the sensitive nature of the environment. With significant depths of these wells, a floating sand screen provides assurance that the sand screen will reach the desired depth. Paraffin is generally used to plug the flow access of the screen during installation. This paper discussed a new technology that has been developed to allow for sand screen installations without relying on paraffin wax to withstand differential pressure. The new technology uses a hydro-mechanical valving system incorporated into the screen design to temporarily close off the screen while being run in the hole. The paper described how the technology could provide a reliable, time-saving solution for SAGD installations when floating sand control screens are needed. The paper discussed current technology and its limitations, sand screen installation, screen design for floating applications, and additional applications. It was concluded that this technology solution provides a unique alternative to the methods currently used to install sand screens with SAGD technology in the fast growing Canadian market for bitumen recovery. 2 refs., 5 figs.

  8. Cavity prediction in sand mould production applying the DISAMATIC process

    DEFF Research Database (Denmark)

    Hovad, Emil; Larsen, Per; Spangenberg, Jon

    2017-01-01

    The sand shot in the DISAMATIC process is simulated by the discrete element method (DEM) taking into account the influence and coupling of the airflow with computational fluid dynamics (CFD). The DEM model is calibrated by a ring shear test, a sand pile experiment and a slump test. Subsequently...

  9. Ecosystem-based design rules for marine sand extraction sites

    NARCIS (Netherlands)

    Jong, de Maarten F.; Borsje, Bas W.; Baptist, Martin J.; Wal, van der Jan Tjalling; Lindeboom, Han J.; Hoekstra, Piet

    2016-01-01

    The demand for marine sand in the Netherlands as well as globally is increasing. Over the last decades, only shallow sand extraction of 2m below the seabed was allowed on the Dutch Continental Shelf (DCS). To guarantee sufficient supply and to decrease the surface area of direct impact, the Dutch

  10. Ecosystem-based design rules for marine sand extraction sites

    NARCIS (Netherlands)

    de Jong, Maarten F.; Borsje, Bas W.; Baptist, Martin J.; van der Wal, Jan Tjalling; Lindeboom, Han J.; Hoekstra, Piet

    2016-01-01

    The demand for marine sand in the Netherlands as well as globally is increasing. Over the last decades, only shallow sand extraction of 2m below the seabed was allowed on the Dutch Continental Shelf (DCS). To guarantee sufficient supply and to decrease the surface area of direct impact, the Dutch

  11. Sorption of europium by Haro river sand in aqueous solution

    International Nuclear Information System (INIS)

    Syed Moosa Hasany; Syed Javaid Khurshid

    1997-01-01

    The sorption of Eu(III) on Haro river sand has been investigated. Influences include composition of the sorptive medium, the concentration of sorbent and sorbate, and shaking time. Haro river sand can be exploited for the preconcentration and removal of europium from very dilute solutions, for the decontamination and treatment of radioactive waste water and effluents from nuclear installations. (Author)

  12. Effects of oil sands sediments on fish

    International Nuclear Information System (INIS)

    Parrott, J.; Colavecchia, M.; Hewitt, L.; Sherry, J.; Headley, J.; Turcotte, D.; Liber, K.

    2010-01-01

    This paper described a collaborative project organized by Natural Resources Canada (NRCan) Panel of Energy Research and Development (PERD) with researchers from Environment Canada and the University of Saskatchewan. The 4-year study was conducted to assess the toxicity of oil sands sediments and river waters, and reclamation ponds and sediments on laboratory-raised fish. Three sediments from rivers were evaluated for their potential to cause adverse impacts on fathead minnow eggs and larvae for a period of 18 days. The study monitored hatching, larval survival, development, and growth. Naphthenic acids (NA), polycyclic aromatic hydrocarbons (PAHs) and metals were measured in the sediments to determine if the compounds can be correlated with observed toxicity. The study will also assess walleye eggs exposed to sediments, and in situ fish exposures. Toxicity identification and evaluation (TIE) studies will be conducted to isolate the fractions that may affect fish development and growth.

  13. The state of oil sands wetland reclamation

    Energy Technology Data Exchange (ETDEWEB)

    Foote, L. [Alberta Univ., Edmonton, AB (Canada)

    2010-07-01

    The state of oil sand and wetlands reclamation was the subject of this presentation. Wildlife habitat and response, plant community and production, and microbial biology were examples of research areas surrounding this body of knowledge. Hydrological research and landscape ecology were discussed along with peatlands and marshes such as the Corvette and the Kia. A few examples of what has been learned in the area of wetlands reclamation was presented. Other topics were also discussed, such as timeframes, pragmatic policy approaches, reclamation costs, research needs and some ideas on maturing the field. It was concluded that environmental conditions change with time and area because of time, chemistry, physics, stoichiometry, as well as biotic mediation and facilitation. figs.

  14. Petro-Canada's oil sands supply outlook

    International Nuclear Information System (INIS)

    Sangster, B.

    2004-01-01

    A report by the Canadian Energy Research Institute suggests that by 2017, production from the Athabasca Oil Sands could reach as high as 3.5 million barrels per day (mbpd), or it could be as low as 1.1 mbpd. This uncertainty in production is due to several variables such as capital costs, project size, reservoir quality, pipeline capacity and workforce productivity. Other factors that influence production include marginal economics, markets and prices, investor confidence, stakeholder concerns and the Kyoto Protocol. The production level that will be achieved by 2017 will depend on how industry address these emerging issues. The author discussed these issues in detail with particular reference to the approach that Petro-Canada has taken to address the challenges. Suggestions to reduce the potential impacts of these challenges were also presented. tabs., figs

  15. Bison and the oil sands industry

    International Nuclear Information System (INIS)

    Pauls, R.W.

    1998-01-01

    Syncrude's Mildred Lake oil sands development project is located within the central boreal mixed wood forest in an area supporting traditional land uses, including trapping and harvesting of wildlife and plant materials by Fort McKay First Nation residents, in a community within 10 km of the Syncrude development. Reclamation requirements and standards in Alberta specify that the reclamation process must restore a landscape capability equivalent to, or better than that existing before disturbance. Syncrude is committed to complying with all provincial requirements and guidelines in all aspects of its business, including land reclamation. A five year research program has been established to determine the feasibility of reclaiming a portion of the landscape to support wood bison and bison subspecies once indigenous to this area. The current project may be expanded as a pilot commercial ranching venture to explore its commercial viability as a business venture by the Fort McKay First nations

  16. Direct Production of Silicones From Sand

    Energy Technology Data Exchange (ETDEWEB)

    Larry N. Lewis; F.J. Schattenmann: J.P. Lemmon

    2001-09-30

    Silicon, in the form of silica and silicates, is the second most abundant element in the earth's crust. However the synthesis of silicones (scheme 1) and almost all organosilicon chemistry is only accessible through elemental silicon. Silicon dioxide (sand or quartz) is converted to chemical-grade elemental silicon in an energy intensive reduction process, a result of the exceptional thermodynamic stability of silica. Then, the silicon is reacted with methyl chloride to give a mixture of methylchlorosilanes catalyzed by cooper containing a variety of tract metals such as tin, zinc etc. The so-called direct process was first discovered at GE in 1940. The methylchlorosilanes are distilled to purify and separate the major reaction components, the most important of which is dimethyldichlorosilane. Polymerization of dimethyldichlorosilane by controlled hydrolysis results in the formation of silicone polymers. Worldwide, the silicones industry produces about 1.3 billion pounds of the basic silicon polymer, polydimethylsiloxane.

  17. Seasonal geomorphic processes and rates of sand movement at Mount Baldy dune in Indiana, USA

    Science.gov (United States)

    Kilibarda, Zoran; Kilibarda, Vesna

    2016-12-01

    Winds are very strong, frequent, and have high energy (annual DP ∼800 VU) along the southern shores of Lake Michigan, allowing the coexistence of fixed and active dunes. Six years (2007-13) of monitoring Mount Baldy in the Indiana Dunes National Lakeshore reveals that this is the most active coastal dune in the Great Lakes region. This paper documents aeolian processes and changes in the dune's morphology that occur temporarily, following storms, or seasonally, due to weather (climate) variations. Most of the sand transport in this area takes place during strong storms with gale force (>17.5 m/s) winds, which occur in the autumn and winter months. A single storm, such as the October 28-31, 2013 event, can contribute 25% of the annual sand transport and dune movement inland. In its most active year (June 1, 2011 through May 31, 2012), Mount Baldy moved inland on average 4.34 m, with a maximum of 6.52 m along the blowout's axis (155° azimuth). During this particularly active season, there were six storms with sustained gale force winds, winter air temperatures were warmer than average, and shelf ice on Lake Michigan lasted only one day. The dune is least active during the summer season, when the winds are weakest. The late fall and winter winds are the strongest. But in a typical year, most of the dune's advance inland takes place during the spring thaw when sand is released from over-steepened and lumpy slip face, allowing it to avalanche to the toe of the slip face. However, with a warming air temperatures, a reduction in the duration of winter shelf ice, and rising Lake Michigan levels, the annual rates of sand transport and dune movement may increase. The recent Mount Baldy management strategy, which includes planting vegetation and installing wind barriers on the dune's stoss side in an effort to fix the dune and stop its further movement inland, may potentially cause the destruction of the mobile sand, open dune habitat, resulting in the extinction of rare

  18. Comparison of vegetation roughness descriptions

    NARCIS (Netherlands)

    Augustijn, Dionysius C.M.; Huthoff, Freek; van Velzen, E.H.; Altinakar, M.S.; Kokpinar, M.A.; Aydin, I.; Cokgor, S.; Kirkgoz, S.

    2008-01-01

    Vegetation roughness is an important parameter in describing flow through river systems. Vegetation impedes the flow, which affects the stage-discharge curve and may increase flood risks. Roughness is often used as a calibration parameter in river models, however when vegetation is allowed to

  19. Recycling of petroleum-contaminated sand.

    Science.gov (United States)

    Taha, R; Ba-Omar, M; Pillay, A E; Roos, G; al-Hamdi, A

    2001-08-01

    The environmental impact of using petroleum-contaminated sand (PCS) as a substitute in asphalt paving mixtures was examined. An appreciable component of PCS is oily sludge, which is found as the dregs in oil storage tanks and is also produced as a result of oil spills on clean sand. The current method for the disposal of oily sludge is land farming. However, this method has not been successful as an oil content of reuse of the sludge in asphalt paving mixtures was therefore considered as an alternative. Standard tests and environmental studies were conducted to establish the integrity of the materials containing the recycled sludge. These included physical and chemical characterization of the sludge itself, and an assessment of the mechanical properties of materials containing 0%, 5%, 22% and 50% oily sludge. The blended mixtures were subjected to special tests, such as Marshall testing and the determination of stability and flow properties. The experimental results indicated that mixtures containing up to 22% oily sludge could meet the necessary criteria for a specific asphalt concrete wearing course or bituminous base course. To maximize the assay from the recycled material, the environmental assessment was restricted to the 50% oily sludge mixture. Leachates associated with this particular mixture were assayed for total organic residue and certain hazardous metal contaminants. The results revealed that the organics were negligible, and the concentrations of the metals were not significant. Thus, no adverse environmental impact should be anticipated from the use of the recycled product. Our research showed that the disposal of oily sludge in asphalt paving mixtures could possibly yield considerable savings per tonne of asphalt concrete, and concurrently minimize any direct impact on the environment.

  20. Improvement of composition of core sand and molding sand mixtures for power machine building castings

    International Nuclear Information System (INIS)

    Velikanov, G.F.; Primak, I.N.; Brechko, A.A.

    1982-01-01

    Considered is a problem of development and improvement of mixtures, as well as of antisticking coatings with the given parameters providing production of castings of the necessary quality. Requirements to properties of mixtures and antisticking coatings are formulated proceeding from the conditions of guaranteed production of qualitative steel castings with mass from 0.5 up to 20t and wall thickness from 60 up to 200 mm. Formation of film structure of binding compositions is studied, their marginal contact angle and surface tension are determined. In the result of work carried out on improvement of core sand and molding sand mixtures the labour productivity during the production of core and moldings has been increased in 20-25% in average, the quality has also been improved [ru

  1. Remediation of trichloroethylene-contaminated soils by star technology using vegetable oil smoldering.

    Science.gov (United States)

    Salman, Madiha; Gerhard, Jason I; Major, David W; Pironi, Paolo; Hadden, Rory

    2015-03-21

    Self-sustaining treatment for active remediation (STAR) is an innovative soil remediation approach based on smoldering combustion that has been demonstrated to effectively destroy complex hydrocarbon nonaqueous phase liquids (NAPLs) with minimal energy input. This is the first study to explore the smoldering remediation of sand contaminated by a volatile NAPL (trichloroethylene, TCE) and the first to consider utilizing vegetable oil as supplemental fuel for STAR. Thirty laboratory-scale experiments were conducted to evaluate the relationship between key outcomes (TCE destruction, rate of remediation) to initial conditions (vegetable oil type, oil: TCE mass ratio, neat versus emulsified oils). Several vegetable oils and emulsified vegetable oil formulations were shown to support remediation of TCE via self-sustaining smoldering. A minimum concentration of 14,000 mg/kg canola oil was found to treat sand exhibiting up to 80,000 mg/kg TCE. On average, 75% of the TCE mass was removed due to volatilization. This proof-of-concept study suggests that injection and smoldering of vegetable oil may provide a new alternative for driving volatile contaminants to traditional vapour extraction systems without supplying substantial external energy. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Big picture thinking in oil sands tailings disposal

    Energy Technology Data Exchange (ETDEWEB)

    Boswell, J. [Thurber Engineering Ltd., Calgary, AB (Canada)

    2010-07-01

    This PowerPoint presentation discussed methods of disposing oil sands tailings. Oil sands operators are currently challenged by a variety of legislative and environmental factors concerning the creation and disposal of oil sands tailings. The media has focused on the negative ecological impact of oil sands production, and technical issues are reducing the effect of some mitigation processes. Operators must learn to manage the interface between tailings production and removal, the environment, and public opinion. The successful management of oil sand tailings will include procedures designed to improve reclamation processes, understand environmental laws and regulations, and ensure that the cumulative impacts of tailings are mitigated. Geotechnical investigations, engineering designs and various auditing procedures can be used to develop tailings management plans. Environmental screening and impact assessments can be used to develop sustainable solutions. Public participation and environmental mediation is needed to integrate the public, environmental and technical tailings management strategies. Operators must ensure public accountability for all stakeholders. tabs., figs.

  3. Compressive Strength of Compacted Clay-Sand Mixes

    Directory of Open Access Journals (Sweden)

    Faseel Suleman Khan

    2014-01-01

    Full Text Available The use of sand to improve the strength of natural clays provides a viable alternative for civil infrastructure construction involving earthwork. The main objective of this note was to investigate the compressive strength of compacted clay-sand mixes. A natural clay of high plasticity was mixed with 20% and 40% sand (SP and their compaction and strength properties were determined. Results indicated that the investigated materials exhibited a brittle behaviour on the dry side of optimum and a ductile behaviour on the wet side of optimum. For each material, the compressive strength increased with an increase in density following a power law function. Conversely, the compressive strength increased with decreasing water content of the material following a similar function. Finally, the compressive strength decreased with an increase in sand content because of increased material heterogeneity and loss of sand grains from the sides during shearing.

  4. Laboratory Test Setup for Cyclic Axially Loaded Piles in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina; Ibsen, Lars Bo; Andersen, Lars Vabbersgaard

    2017-01-01

    This paper presents a comprehensive description and the considerations regarding the design of a new laboratory test setup for testing cyclic axially loaded piles in sand. The test setup aims at analysing the effect of axial one-way cyclic loading on pile capacity and accumulated displacements....... Another aim was to test a large diameter pile segment with dimensions resembling full-scale piles to model the interface properties between pile and sand correctly. The pile segment was an open-ended steel pipe pile with a diameter of 0.5 m and a length of 1 m. The sand conditions resembled the dense sand...... determined from the API RP 2GEO standard and from the test results indicated over consolidation of the sand. Two initial one-way cyclic loading tests provided results of effects on pile capacity and accumulated displacements in agreement with other researchers’ test results....

  5. Modelling the behavior of an oil saturated sand

    International Nuclear Information System (INIS)

    Evgin, E.; Altaee, A.; Lord, S.; Konuk, I.

    1990-01-01

    The experiments carried out in an earlier study show the oil contamination affects the strength and deformation characteristics of a crushed quartz sand. In the present study, a mathematical soil model is used to simulate the mechanical behavior of the same sand. The model parameters are determined for both clean and oil contaminated soil. Simulations are made for the stress-strain behavior of the soil in drained and undrained conventional traixial compression tests. In order to illustrate the effect of changes in the soil properties on the behavior of an engineering structure, a finite element analysis is carried out. In this paper comparative results are presented to show the differences in the behavior of a foundation resting on a clean sand, on an oil contaminated sand, and on a sand contaminated locally

  6. Sand impaction of the small intestine in eight dogs.

    Science.gov (United States)

    Moles, A D; McGhite, A; Schaaf, O R; Read, R

    2010-01-01

    To describe signalment, clinical findings, imaging and treatment of intestinal sand impaction in the dog. Medical records of dogs with radiographic evidence of small intestinal sand impaction were reviewed. Sand impaction resulting in small intestinal obstruction was diagnosed in eight dogs. All dogs presented with signs of vomiting. Other clinical signs included anorexia, lethargy and abdominal pain. Radiographs confirmed the presence of radio-opaque material consistent with sand causing distension of the terminal small intestine in all dogs. Four dogs were treated surgically for their impaction and four dogs were managed medically. Seven of the eight dogs survived. Both medical and surgical management of intestinal sand impaction in the dog can be effective and both afford a good prognosis for recovery.

  7. Remediation of trichloroethylene-contaminated soils by star technology using vegetable oil smoldering

    OpenAIRE

    Salman, Madiha; Gerhard, Jason I.; Major, David W.; Pironi, Paolo; Hadden, Rory

    2015-01-01

    Self-sustaining treatment for active remediation (STAR) is an innovative soil remediation approach based on smoldering combustion that has been demonstrated to effectively destroy complex hydrocarbon nonaqueous phase liquids (NAPLs) with minimal energy input. This is the first study to explore the smoldering remediation of sand contaminated by a volatile NAPL (trichloroethylene, TCE) and the first to consider utilizing vegetable oil as supplemental fuel for STAR. Thirty laboratory-scale exper...

  8. About rehabilitation of vegetation of disturbed ecosystems of the Semipalatinsk test sites

    International Nuclear Information System (INIS)

    Plisak, R.P.; Plisak, S.V.

    2005-01-01

    Full text: Semipalatinsk Test Sites are the place where 470 nuclear tests were conducted in 1949-1989: 26 surface, 87 air, 357 underground. Total area of polluted territories within the test sites reaches 400 square kilometers and 32 squire kilometers at adjoining territory. Radioactive precipitation spread at the territory of 304 thousand square kilometers by traces of radioactive clouds. The precipitation promoted negative processes in environment and damaged public health. One of the most negative factors is products of nuclear decay after underground nuclear tests. They accumulate in soil. Vertical and horizontal migration of radionuclides occurs. The radionuclides accumulate in plants and reach human organism through food chain. Vegetation cover of former Semipalatinsk Test Sites was partly destroyed or damaged on the test sites mentioned above. Nuclear explosions, military and technical construction, building of roads and communication network were conducted out here. Present vegetation cover of breached areas is represented by plant aggregations and communities. They are attributed to different stages of the process of restoration of initial (steppe) vegetation. Rates of rehabilitation of breached ecosystems are conditioned by degree of moisture and properties of formed technogene substratum (soil texture, presence of detritus, and quantity of fine earth). The higher rates of rehabilitation of breached vegetation are typical for ecosystems of flood lands, depressions between hills and slopes of hills of northern exposition. Rehabilitation of zonal ecosystems (sagebrush-eather-grass communities on light chestnut soils) in conditions of arid climate and insignificant water content in substratum of technogene objects proceeds slowly. Rates of restoration of haloxerophyte communities are conditioned by additional moistening of surface washing down of moist ure into micro depressions occupied by sanotiazol. The process of vegetation rehabilitation of damaged

  9. Impacts of oil sands process water on fen plants: Implications for plant selection in required reclamation projects

    International Nuclear Information System (INIS)

    Pouliot, Rémy; Rochefort, Line; Graf, Martha D.

    2012-01-01

    Fen plant growth in peat contaminated with groundwater discharges of oil sands process water (OSPW) was assessed in a greenhouse over two growing seasons. Three treatments (non-diluted OSPW, diluted OSPW and rainwater) were tested on five vascular plants and four mosses. All vascular plants tested can grow in salinity and naphthenic acids levels currently produced by oil sands activity in northwestern Canada. No stress sign was observed after both seasons. Because of plant characteristics, Carex species (C. atherodes and C. utriculata) and Triglochin maritima would be more useful for rapidly restoring vegetation and creating a new peat-accumulating system. Groundwater discharge of OSPW proved detrimental to mosses under dry conditions and ensuring adequate water levels would be crucial in fen creation following oil sands exploitation. Campylium stellatum would be the best choice to grow in contaminated areas and Bryum pseudotriquetrum might be interesting as it has spontaneously regenerated in all treatments. - Highlights: ► Fen plant growth was assessed under groundwater discharges of oil sands process water. ► Sedge and grass species were not stressed after two growing seasons in greenhouse. ► Carex species and Triglochin maritima would be helpful in created contaminated fens. ► In dry conditions, contaminated groundwater discharge was detrimental for mosses. ► Campylium stellatum would be the best choice in created fens with contaminated water. - Sedges and grasses tolerated the contact with oil sands process water and could probably grow well in contaminated created fens, but mosses were particularly affected under dry conditions.

  10. Aeolian sand transport and aeolian deposits on Venus: A review

    Science.gov (United States)

    Kreslavsly, Mikhail A.; Bondarenko, Nataliya V.

    2017-06-01

    We review the current state of knowledge about aeolian sand transport and aeolian bedforms on planet Venus. This knowledge is limited by lack of observational data. Among the four planetary bodies of the Solar System with sufficient atmospheres in contact with solid surfaces, Venus has the densest atmosphere; the conditions there are transitional between those for terrestrial subaerial and subaqueous transport. The dense atmosphere causes low saltation threshold and short characteristic saltation length, and short scale length of the incipient dunes. A few lines of evidence indicate that the typical wind speeds exceed the saltation threshold; therefore, sand transport would be pervasive, if sand capable of saltation is available. Sand production on Venus is probably much slower than on the Earth; the major terrestrial sand sinks are also absent, however, lithification of sand through sintering is expected to be effective under Venus' conditions. Active transport is not detectable with the data available. Aeolian bedforms (transverse dunes) resolved in the currently available radar images occupy a tiny area on the planet; however, indirect observations suggest that small-scale unresolved aeolian bedforms are ubiquitous. Aeolian transport is probably limited by sand lithification causing shortage of saltation-capable material. Large impact events likely cause regional short-term spikes in aeolian transport by supplying a large amount of sand-size particles, as well as disintegration and activation of older indurated sand deposits. The data available are insufficient to understand whether the global aeolian sand transport occurs or not. More robust knowledge about aeolian transport on Venus is essential for future scientific exploration of the planet, in particular, for implementation and interpretation of geochemical studies of surface materials. High-resolution orbital radar imaging with local to regional coverage and desirable interferometric capabilities is the

  11. Sand waves on an epicontinental shelf: Northern Bering Sea

    Science.gov (United States)

    Field, M.E.; Nelson, C.H.; Cacchione, D.A.; Drake, D.E.

    1981-01-01

    Sand waves and current ripples occupy the crests and flanks of a series of large linear sand ridges (20 km ?? 5 km ?? 10 m high) lying in an open-marine setting in the northern Bering Sea. The sand wave area, which lies west of Seward Peninsula and southeast of Bering Strait, is exposed to the strong continuous flow of coastal water northward toward Bering Strait. A hierarchy of three sizes of superimposed bedforms, all facing northward, was observed in successive cruises in 1976 and 1977. Large sand waves (height 2 m; spacing 200 m) have smaller sand waves (height 1 m; spacing 20 m) lying at a small oblique angle on their stoss slopes. The smaller sand waves in turn have linguoid ripples on their stoss slopes. Repeated studies of the sand wave fields were made both years with high-resolution seismic-reflection profiles, side-scan sonographs, underwater photographs, current-meter stations, vibracores, and suspended-sediment samplers. Comparison of seismic and side-scan data collected along profile lines run both years showed changes in sand wave shape that indicate significant bedload transport within the year. Gouge marks made in sediment by keels of floating ice also showed significantly different patterns each year, further documenting modification to the bottom by sediment transport. During calm sea conditions in 1977, underwater video and camera observations showed formation and active migration of linguoid and straight-crested current ripples. Current speeds 1 m above the bottom were between 20 and 30 cm/s. Maximum current velocities and sand wave migration apparently occur when strong southwesterly winds enhance the steady northerly flow of coastal water. Many cross-stratified sand bodies in the geologic record are interpreted as having formed in a tidal- or storm-dominated setting. This study provides an example of formation and migration of large bedforms by the interaction of storms with strong uniform coastal currents in an open-marine setting. ?? 1981.

  12. Oblique second-order sand transport pathways on an intertidal sand flat in a natural tidal inlet system

    DEFF Research Database (Denmark)

    Ernstsen, Verner Brandbyge; Lefebvre, Alice; Kroon, Aart

    2013-01-01

    tide, sand is transported along ESE-oriented pathways across the intertidal flat towards the inner tidal basin. During the late stages of ebb tide, sand is transported in drainage channels (WSWoriented) from the intertidal flat towards the inlet channel. During storm events with winds from SW, wave...

  13. The Geodiversity in Drift Sand Landscapes of The Netherlands

    Science.gov (United States)

    van den Ancker, Hanneke; Jungerius, Pieter Dirk; Riksen, Michel

    2015-04-01

    The authors carried out detailed field studies of more than twelve drift sand landscapes in The Netherlands. The objective of these studies was to restore Natura-2000 values by restoring the wind activity. Active drift sands occur almost exclusively in The Netherlands, Natura 2000 habitat 2330 'Inland dunes with open Corynephorus and Agrostis grasslands', for which reason our country is largely responsible for this European landscape. Active drift sands had almost disappeared for two reasons: first, the stabilization of the drift sands by air pollution, mainly nitrogen, which stimulates the growth of algae and grasses that initiate soil formation, and second, by the growth of forests surrounding the sands, which decreases the wind force. The restoration studies revealed differences in the geodiversity between and within the drift sand areas. Whereas the drift sands on geological and soil maps show as almost homogenous areas, they have in fact highly variable geo-conditions of which examples will be given. These geodiversity aspects concern differences in geomorphological structure, origin, sediments and age of the drift sands. Differences in wind and water erosion, trampling and soil formation add to the geodiversity within the drift sand areas. Especially in the primary stages of succession the differences in geodiversity are relevant for the Natura-2000 values. We discerned three main types of active sands. Firstly, the impressive drift sands with large parabolic dune structures, often consisting of series of interlocking parabolic dunes. They developed from the northeast towards the southwest, against the direction of the dominant wind, and must have taken centuries to develop. Small parts of these systems are still active, other parts show different degrees of soil formation. Their origin is still unclear but probably dates from medieval times (Heidinga, 1985, Jungerius & Riksen, 2008). Second are the drift sand areas with irregular hills from 0.5 to about 2

  14. Agglomeration of a comprehensive model for the wind-driven sand transport at the Belgian Coast

    Science.gov (United States)

    Strypsteen, Glenn; Rauwoens, Pieter

    2016-04-01

    Although a lot of research has been done in the area of Aeolian transport, it is only during the last years that attention has been drawn to Aeolian transport in coastal areas. In these areas, the physical processes are more complex, due to a large number of transport limiting parameters. In this PhD-project, which is now in its early stage, a model will be developed which relates the wind-driven sand transport at the Belgian coast with physical parameters such as the wind speed, humidity and grain size of the sand, and the slope of beach and dune surface. For the first time, the interaction between beach and dune dynamics is studied at the Belgian coast. The Belgian coastline is only 67km long, but densely populated and therefore subject to coastal protection and safety. The coast mostly consists of sandy beaches and dikes. Although, still 33km of dunes exist, whose dynamics are far less understood. The overall research approach consists of three pathways: (i) field measurements, (ii) physical model tests, and (iii) numerical simulations. Firstly and most importantly, several field campaigns will provide accurate data of meteo-marine conditions, morphology, and sand transport events on a wide beach at the Belgian Coastline. The experimental set-up consists of a monitoring station, which will provide time series of vegetation cover, shoreline position, fetch distances, surficial moisture content, wind speed and direction and transport processes. The horizontal and vertical variability of the event scale Aeolian sand transport is analyzed with 8 MWAC sand traps. Two saltiphones register the intensity and variations of grain impacts over time. Two meteo-masts, each with four anemometers and one wind vane, provide quantitative measurements of the wind flow at different locations on the beach. Surficial moisture is measured with a moisture sensor. The topography measurements are typically done with laser techniques. To start, two sites are selected for measurement

  15. Influence of sand base preparation on properties of chromite moulding sands with sodium silicate hardened with selected methods

    Directory of Open Access Journals (Sweden)

    Stachowicz M.

    2017-03-01

    Full Text Available The paper presents a research on the relation between thermal preparation of chromite sand base of moulding sands containing sodium silicate, hardened with selected physical and chemical methods, and structure of the created bonding bridges. Test specimens were prepared of chromite sand - fresh or baked at 950°C for 10 or 24 hours - mixed with 0.5 wt.% of the selected non-modified inorganic binder and, after forming, were hardened with CO2 or liquid esters, dried traditionally or heated with microwaves at 2.45 GHz. It was shown on the grounds of SEM observations that the time of baking the base sand and the hardening method significantly affect structure of the bonding bridges and are correlated with mechanical properties of the moulding sands. It was found that hardening chromite-based moulding mixtures with physical methods is much more favourable than hardening with chemical methods, guaranteeing also more than ten times higher mechanical properties.

  16. The Carolina Sandhills: Quaternary eolian sand sheets and dunes along the updip margin of the Atlantic Coastal Plain province, southeastern United States

    Science.gov (United States)

    Swezey, Christopher; Fitzwater, Bradley A.; Whittecar, G. Richard; Mahan, Shannon; Garrity, Christopher P.; Aleman Gonzalez, Wilma B.; Dobbs, Kerby M.

    2016-01-01

    The Carolina Sandhills is a physiographic region of the Atlantic Coastal Plain province in the southeastern United States. In Chesterfield County (South Carolina), the surficial sand of this region is the Pinehurst Formation, which is interpreted as eolian sand derived from the underlying Cretaceous Middendorf Formation. This sand has yielded three clusters of optically stimulated luminescence ages: (1) 75 to 37 thousand years ago (ka), coincident with growth of the Laurentide Ice Sheet; (2) 28 to 18 ka, coincident with the last glacial maximum (LGM); and (3) 12 to 6 ka, mostly coincident with the Younger Dryas through final collapse of the Laurentide Ice Sheet. Relict dune morphologies are consistent with winds from the west or northwest, coincident with modern and inferred LGM January wind directions. Sand sheets are more common than dunes because of effects of coarse grain size (mean range: 0.35–0.59 mm) and vegetation. The coarse grain size would have required LGM wind velocities of at least 4–6 m/sec, accounting for effects of colder air temperatures on eolian sand transport. The eolian interpretation of the Carolina Sandhills is consistent with other evidence for eolian activity in the southeastern United States during the last glaciation.

  17. Restoration of Black Oak (Quercus velutina) Sand Barrens via Three Different Habitat Management Approaches

    Science.gov (United States)

    Kriska, David John

    Disturbance regimes, i.e. frequent fires, historically maintained oak barrens until European settlement patterns, and eventually, Smoky the Bear and the fire suppression campaign of the U.S. Forest Service snuffed out the periodic flames. In the absence of a disturbance regime, ground layer floral composition at many historical oak sand barrens will change predominantly because of a buildup of leaf litter and shading of the soils. Termed mesophication, this process of ecological succession will drive Black Oak Sand Barrens to an alternate steady state. A survey conducted on Singer Lake Bog in Green, Ohio, demonstrated that succession shifted the community to red maple-black cherry woodlands more typical of a dry southern forest. In an attempt to revive disturbance, three restoration techniques were applied at ten degraded northeast Ohio oak barrens to contrast their effectiveness in restoring black oak sand barren flora. The three restoration treatments were select canopy tree reduction favoring 5% to 30% tree canopy cover, forest floor leaf litter removal, and prescribed fire. Vegetation responses to manipulations were monitored prior to and following treatment applications, and were compared against both baseline data from before-treatment surveys and paired control sites adjacent treated areas. Imposing disturbance successfully increased species diversity and abundance above that found across Singer Lake Bog compared to sampling made prior to and adjacent to treated areas. Select canopy tree removal exhibited the largest floral responses from targeted barrens species, i.e. graminoids. A forest floor invertebrate family (Carabidea: Coleoptera) was measured for species richness and abundance pre and post treatment, where a noticeable shift occurred away from woodland obligate ground beetles toward open grassland species. Replicating oak barren structure, prior to replicating disturbance processes, is the first step in the ecological restoration of these systems.

  18. Ecosystem engineering varies spatially: a test of the vegetation modification paradigm for prairie dogs

    Science.gov (United States)

    Baker, Bruce W.; Augustine, David J.; Sedgwick, James A.; Lubow, Bruce C.

    2013-01-01

    Colonial, burrowing herbivores can be engineers of grassland and shrubland ecosystems worldwide. Spatial variation in landscapes suggests caution when extrapolating single-place studies of single species, but lack of data and the need to generalize often leads to ‘model system’ thinking and application of results beyond appropriate statistical inference. Generalizations about the engineering effects of prairie dogs (Cynomys sp.) developed largely from intensive study at a single complex of black-tailed prairie dogs C. ludovicianus in northern mixed prairie, but have been extrapolated to other ecoregions and prairie dog species in North America, and other colonial, burrowing herbivores. We tested the paradigm that prairie dogs decrease vegetation volume and the cover of grasses and tall shrubs, and increase bare ground and forb cover. We sampled vegetation on and off 279 colonies at 13 complexes of 3 prairie dog species widely distributed across 5 ecoregions in North America. The paradigm was generally supported at 7 black-tailed prairie dog complexes in northern mixed prairie, where vegetation volume, grass cover, and tall shrub cover were lower, and bare ground and forb cover were higher, on colonies than at paired off-colony sites. Outside the northern mixed prairie, all 3 prairie dog species consistently reduced vegetation volume, but their effects on cover of plant functional groups varied with prairie dog species and the grazing tolerance of dominant perennial grasses. White-tailed prairie dogs C. leucurus in sagebrush steppe did not reduce shrub cover, whereas black-tailed prairie dogs suppressed shrub cover at all complexes with tall shrubs in the surrounding habitat matrix. Black-tailed prairie dogs in shortgrass steppe and Gunnison's prairie dogs C. gunnisoni in Colorado Plateau grassland both had relatively minor effects on grass cover, which may reflect the dominance of grazing-tolerant shortgrasses at both complexes. Variation in modification of

  19. Predicted fire behavior and societal benefits in three eastern Sierra Nevada vegetation types

    Science.gov (United States)

    C.A. Dicus; K. Delfino; D.R. Weise

    2009-01-01

    We investigated potential fire behavior and various societal benefits (air pollution removal, carbon sequestration, and carbon storage) provided by woodlands of pinyon pine (Pinus monophylla) and juniper (Juniperus californica), shrublands of Great Basin sagebrush (Artemisia tridentata) and rabbitbrush (Ericameria nauseosa...

  20. Phenolation of vegetable oils

    Directory of Open Access Journals (Sweden)

    ZORAN S. PETROVIĆ

    2011-04-01

    Full Text Available Novel bio-based compounds containing phenols suitable for the syn­thesis of polyurethanes were prepared. The direct alkylation of phenols with different vegetable oils in the presence of superacids (HBF4, triflic acid as ca­talysts was studied. The reaction kinetics was followed by monitoring the de­crease of the double bond content (iodine value with time. In order to under­stand the mechanism of the reaction, phenol was alkylated with model com­pounds. The model compounds containing one internal double bond were 9-oc­tadecene and methyl oleate and those with three double bonds were triolein and high oleic safflower oil (82 % oleic acid. It was shown that the best structures for phenol alkylation are fatty acids with only one double bond (oleic acid. Fatty acids with two double bonds (linoleic acid and three double bonds (lino­lenic acid lead to polymerized oils by a Diels–Alder reaction, and to a lesser extent to phenol alkylated products. The reaction product of direct alkylation of phenol with vegetable oils is a complex mixture of phenol alkylated with poly­merized oil (30–60 %, phenyl esters formed by transesterification of phenol with triglyceride ester bonds (<10 % and unreacted oil (30 %. The phenolated vegetable oils are new aromatic–aliphatic bio-based raw materials suitable for the preparation of polyols (by propoxylation, ethoxylation, Mannich reactions for the preparation of polyurethanes, as intermediates for phenolic resins or as bio-based antioxidants.