Ground-water flow directions and estimation of aquifer hydraulic properties in the lower Great Miami River Buried Valley aquifer system, Hamilton Area, Ohio

Science.gov (United States)

Sheets, Rodney A.; Bossenbroek, Karen E.

2005-01-01

The Great Miami River Buried Valley Aquifer System is one of the most productive sources of potable water in the Midwest, yielding as much as 3,000 gallons per minute to wells. Many water-supply wells tapping this aquifer system are purposely placed near rivers to take advantage of induced infiltration from the rivers. The City of Hamilton's North Well Field consists of 10 wells near the Great Miami River, all completed in the lower Great Miami River Buried Valley Aquifer System. A well-drilling program and a multiple-well aquifer test were done to investigate ground-water flow directions and to estimate aquifer hydraulic properties in the lower part of the Great Miami River Buried Valley Aquifer System. Descriptions of lithology from 10 well borings indicate varying amounts and thickness of clay or till, and therefore, varying levels of potential aquifer confinement. Borings also indicate that the aquifer properties can change dramatically over relatively short distances. Grain-size analyses indicate an average bulk hydraulic conductivity value of aquifer materials of 240 feet per day; the geometric mean of hydraulic conductivity values of aquifer material was 89 feet per day. Median grain sizes of aquifer material and clay units were 1.3 millimeters and 0.1 millimeters, respectively. Water levels in the Hamilton North Well Field are affected by stream stage in the Great Miami River and barometric pressure. Bank storage in response to stream stage is evident. Results from a multiple-well aquifer test at the well field indicate, as do the lithologic descriptions, that the aquifer is semiconfined in some areas and unconfined in others. Transmissivity and storage coefficient of the semiconfined part of the aquifer were 50,000 feet squared per day and 5x10-4, respectively. The average hydraulic conductivity (450 feet per day) based on the aquifer test is reasonable for glacial outwash but is higher than calculated from grain-size analyses, implying a scale effect

Carbon pools along headwater streams with differing valley geometry in Rocky Mountain National Park, Colorado (Abstract)

Science.gov (United States)

Kathleen A. Dwire; Ellen E. Wohl; Nicholas A. Sutfin; Roberto A. Bazan; Lina Polvi-Pilgrim

2012-01-01

Headwaters are known to be important in the global carbon cycle, yet few studies have investigated carbon (C) pools along stream-riparian corridors. To better understand the spatial distribution of C storage in headwater fluvial networks, we estimated above- and below-ground C pools in 100-m-long reaches in six different valley types in Rocky Mountain National Park,...

Sequential development of platform to off-platform facies of the great American carbonate bank in the central Appalachians: chapter 15

Science.gov (United States)

Brezinski, David K.; Taylor, John F.; Repetski, John E.

2012-01-01

In the central Appalachians, carbonate deposition of the great American carbonate bank began during the Early Cambrian with the creation of initial ramp facies of the Vintage Formation and lower members of the Tomstown Formation. Vertical stacking of bioturbated subtidal ramp deposits (Bolivar Heights Member) and dolomitized microbial boundtsone (Fort Duncan Member) preceded the initiation of platform sedimentation and creation of sand shoal facies (Benevola Member) that was followed by the development of peritidal cyclicity (Daragan Member). Initiation of peritidal deposition coincided with the development of a rimmed platform that would persist throughout much of the Cambrian and Early Odrovician. At the end of deposition of the Waynesboro Formation, the platform became subaerially exposed because of the Hawke Bay regression, bringing the Sauk I supersequence to and end. In the Conestoga Valley of eastern Pennsylvania, Early Cambrian ramp deposition was succeeded by deposition of platform-margin and periplatfrom facies of the Kinzers Formation.

Daytime wind valleys adjacent to the Great Salt Lake

Energy Technology Data Exchange (ETDEWEB)

Stone, G.L. (Los Alamos National Lab., NM (USA)); Hoard, D.E. (Amparo Corp., Santa Fe, NM (USA))

1990-01-01

In 1986 Los Alamos National Laboratory was engaged by the US Army to study the meteorological aspects of emergency preparedness at several sites where toxic materials are stored and handled. The project included a series of tracer and meteorological field experiments in the vicinity of the Tooele Army Depot. These experiments generated a large data set for validating numerical simulations and for empirical analyses of the local meteorology. This paper discusses the main characteristics of the daytime, up-valley flow at the Utah site, including frequency of occurrence, horizontal and vertical structure, and temporal evolution. Some parameters controlling the variability in onset time for up-valley flow are identified, and an empirical forecasting scheme is discussed. 16 refs., 7 figs.

Valley-dependent band structure and valley polarization in periodically modulated graphene

Science.gov (United States)

Lu, Wei-Tao

2016-08-01

The valley-dependent energy band and transport property of graphene under a periodic magnetic-strained field are studied, where the time-reversal symmetry is broken and the valley degeneracy is lifted. The considered superlattice is composed of two different barriers, providing more degrees of freedom for engineering the electronic structure. The electrons near the K and K' valleys are dominated by different effective superlattices. It is found that the energy bands for both valleys are symmetric with respect to ky=-(AM+ξ AS) /4 under the symmetric superlattices. More finite-energy Dirac points, more prominent collimation behavior, and new crossing points are found for K' valley. The degenerate miniband near the K valley splits into two subminibands and produces a new band gap under the asymmetric superlattices. The velocity for the K' valley is greatly renormalized compared with the K valley, and so we can achieve a finite velocity for the K valley while the velocity for the K' valley is zero. Especially, the miniband and band gap could be manipulated independently, leading to an increase of the conductance. The characteristics of the band structure are reflected in the transmission spectra. The Dirac points and the crossing points appear as pronounced peaks in transmission. A remarkable valley polarization is obtained which is robust to the disorder and can be controlled by the strain, the period, and the voltage.

Transient Electromagnetic Soundings Near Great Sand Dunes National Park and Preserve, San Luis Valley, Colorado (2006 Field Season)

Science.gov (United States)

Fitterman, David V.; de Sozua Filho, Oderson A.

2009-01-01

Time-domain electromagnetic (TEM) soundings were made near Great Sand Dunes National Park and Preserve in the San Luis Valley of southern Colorado to obtain subsurface information of use to hydrologic modeling. Seventeen soundings were made to the east and north of the sand dunes. Using a small loop TEM system, maximum exploration depths of about 75 to 150 m were obtained. In general, layered earth interpretations of the data found that resistivity decreases with depth. Comparison of soundings with geologic logs from nearby wells found that zones logged as having increased clay content usually corresponded with a significant resistivity decrease in the TEM determined model. This result supports the use of TEM soundings to map the location of the top of the clay unit deposited at the bottom of the ancient Lake Alamosa that filled the San Luis Valley from Pliocene to middle Pleistocene time.

Carbonate clumped isotopes and in situ temperature monitoring for Holocene soils in the San Luis Valley, USA indicate springtime carbonate formation

Science.gov (United States)

Hudson, A. M.; Paces, J. B.; Ruleman, C.

2017-12-01

Pedogenic carbonate horizons are abundant in semi-arid and arid regions worldwide and within the geologic record. They present a widely distributed archive of past environmental conditions, driven by global climate or tectonically-controlled elevation changes. Oxygen and carbon isotopes in calcite-rich nodules and clast rinds are widely-applied indicators of past soil water and CO2 composition linked to changing precipitation and plant communities. The temperature of carbonate formation, however, provides key constraint on past water/CO2 values and elucidate why they may have changed in the past. Clumped isotope thermometry can provide this constraint and additional climate information, given the carbonate forming system is well understood. We present preliminary clumped isotope (Δ47) temperatures for Holocene soil carbonates, constrained by 14C and U-Th disequilibrium dating, compared with two years of in situ soil temperature data to better understand the mechanism and seasonality of carbonate formation in the San Luis Valley region of the southern Rocky Mountains. Five temperature-monitoring sites ranging in elevation (1940-2450 m) and latitude (36.2-37.9°N) were installed in a variety of settings (range front, valley center, and canyon). The resulting records show indistinguishable seasonal temperature variations at >60 cm depth. This suggests Δ47 temperatures should be comparable at sites across the region. Temperatures based on Δ47 measurements of Holocene (>1.8 to 11.0 ka BP) carbonates at these sites yield consistent inter-site temperatures of 10±4°C, which are similar to modern springtime soil temperatures at depth. This seasonality matches previous results of isotopic modeling at sites further south along the Rio Grande corridor. Temperatures during March to May show multiple, abrupt warming and cooling cycles on weekly timescales caused by wetting and drying of the soil during spring precipitation events. This may drive carbonate precipitation

GHG and black carbon emission inventories from Mezquital Valley: The main energy provider for Mexico Megacity.

Science.gov (United States)

Montelongo-Reyes, M M; Otazo-Sánchez, E M; Romo-Gómez, C; Gordillo-Martínez, A J; Galindo-Castillo, E

2015-09-15

The greenhouse gases and black carbon emission inventory from IPCC key category Energy was accomplished for the Mezquital Valley, one of the most polluted regions in Mexico, as the Mexico City wastewater have been continuously used in agricultural irrigation for more than a hundred years. In addition, thermoelectric, refinery, cement and chemistry industries are concentrated in the southern part of the valley, near Mexico City. Several studies have reported air, soil, and water pollution data and its main sources for the region. Paradoxically, these sources contaminate the valley, but boosted its economic development. Nevertheless, no research has been done concerning GHG emissions, or climate change assessment. This paper reports inventories performed by the 1996 IPCC methodology for the baseline year 2005. Fuel consumption data were derived from priority sectors such as electricity generation, refineries, manufacturing & cement industries, transportation, and residential use. The total CO2 emission result was 13,894.9 Gg, which constituted three-quarters of Hidalgo statewide energy category. The principal CO2 sources were energy transformation (69%) and manufacturing (19%). Total black carbon emissions were estimated by a bottom-up method at 0.66 Gg. The principal contributor was on-road transportation (37%), followed by firewood residential consumption (26%) and cocked brick manufactures (22%). Non-CO2 gas emissions were also significant, particularly SO2 (255.9 Gg), which accounts for 80% of the whole Hidalgo State emissions. Results demonstrated the negative environmental impact on Mezquital Valley, caused by its role as a Megacity secondary fuel and electricity provider, as well as by the presence of several cement industries. Copyright © 2015 Elsevier B.V. All rights reserved.

Potential for a significant deep basin geothermal system in Tintic Valley, Utah

Science.gov (United States)

Hardwick, C.; Kirby, S.

2014-12-01

The combination of regionally high heat flow, deep basins, and permeable reservoir rocks in the eastern Great Basin may yield substantial new geothermal resources. We explore a deep sedimentary basin geothermal prospect beneath Tintic Valley in central Utah using new 2D and 3D models coupled with existing estimates of heat flow, geothermometry, and shallow hydrologic data. Tintic Valley is a sediment-filled basin bounded to the east and west by bedrock mountain ranges where heat-flow values vary from 85 to over 240 mW/m2. Based on modeling of new and existing gravity data, a prominent 30 mGal low indicates basin fill thickness may exceed 2 km. The insulating effect of relatively low thermal conductivity basin fill in Tintic Valley, combined with typical Great Basin heat flow, predict temperatures greater than 150 °C at 3 km depth. The potential reservoir beneath the basin fill is comprised of Paleozoic carbonate and clastic rocks. The hydrology of the Tintic Valley is characterized by a shallow, cool groundwater system that recharges along the upper reaches of the basin and discharges along the valley axis and to a series of wells. The east mountain block is warm and dry, with groundwater levels just above the basin floor and temperatures >50 °C at depth. The west mountain block contains a shallow, cool meteoric groundwater system. Fluid temperatures over 50 °C are sufficient for direct-use applications, such as greenhouses and aquaculture, while temperatures exceeding 140°C are suitable for binary geothermal power plants. The geologic setting and regionally high heat flow in Tintic Valley suggest a geothermal resource capable of supporting direct-use geothermal applications and binary power production could be present.

WRF and WRF-Chem v3.5.1 simulations of meteorology and black carbon concentrations in the Kathmandu Valley

Directory of Open Access Journals (Sweden)

A. Mues

2018-06-01

Full Text Available An evaluation of the meteorology simulated using the Weather Research and Forecast (WRF model for the region of south Asia and Nepal with a focus on the Kathmandu Valley is presented. A particular focus of the model evaluation is placed on meteorological parameters that are highly relevant to air quality such as wind speed and direction, boundary layer height and precipitation. The same model setup is then used for simulations with WRF including chemistry and aerosols (WRF-Chem. A WRF-Chem simulation has been performed using the state-of-the-art emission database, EDGAR HTAP v2.2, which is the Emission Database for Global Atmospheric Research of the Joint Research Centre (JRC of the European Commission, in cooperation with the Task Force on Hemispheric Transport of Air Pollution (TF HTAP organized by the United Nations Economic Commission for Europe, along with a sensitivity simulation using observation-based black carbon emission fluxes for the Kathmandu Valley. The WRF-Chem simulations are analyzed in comparison to black carbon measurements in the valley and to each other.The evaluation of the WRF simulation with a horizontal resolution of 3×3 km2 shows that the model is often able to capture important meteorological parameters inside the Kathmandu Valley and the results for most meteorological parameters are well within the range of biases found in other WRF studies especially in mountain areas. But the evaluation results also clearly highlight the difficulties of capturing meteorological parameters in such complex terrain and reproducing subgrid-scale processes with a horizontal resolution of 3×3 km2. The measured black carbon concentrations are typically systematically and strongly underestimated by WRF-Chem. A sensitivity study with improved emissions in the Kathmandu Valley shows significantly reduced biases but also underlines several limitations of such corrections. Further improvements of the model and of the emission data are

Ground-water quality in the carbonate-rock aquifer of the Great Basin, Nevada and Utah, 2003

Science.gov (United States)

Schaefer, Donald H.; Thiros, Susan A.; Rosen, Michael R.

2005-01-01

The carbonate-rock aquifer of the Great Basin is named for the thick sequence of Paleozoic limestone and dolomite with lesser amounts of shale, sandstone, and quartzite. It lies primarily in the eastern half of the Great Basin and includes areas of eastern Nevada and western Utah as well as the Death Valley area of California and small parts of Arizona and Idaho. The carbonate-rock aquifer is contained within the Basin and Range Principal Aquifer, one of 16 principal aquifers selected for study by the U.S. Geological Survey’s National Water- Quality Assessment Program.Water samples from 30 ground-water sites (20 in Nevada and 10 in Utah) were collected in the summer of 2003 and analyzed for major anions and cations, nutrients, trace elements, dissolved organic carbon, volatile organic compounds (VOCs), pesticides, radon, and microbiology. Water samples from selected sites also were analyzed for the isotopes oxygen-18, deuterium, and tritium to determine recharge sources and the occurrence of water recharged since the early 1950s.Primary drinking-water standards were exceeded for several inorganic constituents in 30 water samples from the carbonate-rock aquifer. The maximum contaminant level was exceeded for concentrations of dissolved antimony (6 μg/L) in one sample, arsenic (10 μg/L) in eleven samples, and thallium (2 μg/L) in one sample. Secondary drinking-water regulations were exceeded for several inorganic constituents in water samples: chloride (250 mg/L) in five samples, fluoride (2 mg/L) in two samples, iron (0.3 mg/L) in four samples, manganese (0.05 mg/L) in one sample, sulfate (250 mg/L) in three samples, and total dissolved solids (500 mg/L) in seven samples.Six different pesticides or metabolites were detected at very low concentrations in the 30 water samples. The lack of VOC detections in water sampled from most of the sites is evidence thatVOCs are not common in the carbonate-rock aquifer. Arsenic values for water range from 0.7 to 45.7 �

Preliminary evaluation of the radioactive waste isolation potential of the alluvium-filled valleys of the Great Basin

International Nuclear Information System (INIS)

Smyth, J.R.; Crowe, B.M.; Halleck, P.M.; Reed, A.W.

1979-08-01

The occurrences, geologic features, hydrology, and thermal, mechanical, and mineralogical properties of the alluvium-filled valleys are compared with those of other media within the Great Basin. Computer modeling of heat conduction indicates that heat generated by the radioactive waste can be dissipated through the alluvium in a manner that will not threaten the integrity of the repository, although waste emplacement densities will be lower than for other media available. This investigation has not revealed any failure mechanism by which one can rule out alluvium as a primary waste isolation medium. However, the alluvium appears to rank behind one or more other possible media in all properties examined except, perhaps, in sorption properties. It is therefore recommended that alluvium be considered as a secondary isolation medium unless primary sites in other rock types in the Great Basin are eliminated from consideration on grounds other than those considered here

The carbon stable isotope biogeochemistry of streams, Taylor Valley, Antarctica

International Nuclear Information System (INIS)

Lyons, W.B.; Leslie, D.L.; Harmon, R.S.; Neumann, K.; Welch, K.A.; Bisson, K.M.; McKnight, D.M.

2013-01-01

Highlights: ► δ 13 C-DIC reported from McMurdo Dry Valleys, Antarctica, streams. ► Stream water δ 13 C PDB values range −9.4‰ to +5.1‰, largely inorganic in character. ► Atmospheric exchange is the dominant control on δ 13 C-DIC. - Abstract: The McMurdo Dry Valleys region of Antarctica is the largest ice-free region on the continent. This study reports the first C stable isotope measurements for dissolved inorganic C present in ephemeral streams in four dry valleys that flow for four to twelve weeks during the austral summer. One of these valleys, Taylor Valley, has been the focus of the McMurdo Dry Valleys Long-Term Ecological Research (MCM-LTER) program since 1993. Within Taylor Valley, numerous ephemeral streams deliver water to three perennially ice-covered, closed-basin lakes: Lake Fryxell, Lake Hoare, and Lake Bonney. The Onyx River in the Wright Valley, the longest river in Antarctica, flows for 40 km from the Wright Lower Glacier and Lake Brownworth at the foot of the glacier to Lake Vanda. Streamflow in the McMurdo Dry Valley streams is produced primarily from glacial melt, as there is no overland flow. However, hyporheic zone exchange can be a major hydrogeochemical process in these streams. Depending on landscape position, these streams vary in gradient, channel substrate, biomass abundance, and hyporheic zone extent. This study sampled streams from Taylor, Wright, Garwood, and Miers Valleys and conducted diurnal sampling of two streams of different character in Taylor Valley. In addition, transect sampling was undertaken of the Onyx River in Wright Valley. The δ 13 C PDB values from these streams span a range of greater than 14‰, from −9.4‰ to +5.1‰, with the majority of samples falling between −3‰ and +2‰, suggesting that the C stable isotope composition of dissolved C in McMurdo Dry Valley streams is largely inorganic in character. Because there are no vascular plants on this landscape and no groundwater input to these

Death Valley Lower Carbonate Aquifer Monitoring Program Wells Down gradient of the Proposed Yucca Mountain Nuclear Waste Repository

International Nuclear Information System (INIS)

Inyo County

2006-01-01

Inyo County has participated in oversight activities associated with the Yucca Mountain Nuclear Waste Repository since 1987. The overall goal of these studies are the evaluation of far-field issues related to potential transport, by ground water, or radionuclides into Inyo County, including Death Valley, and the evaluation of a connection between the Lower Carbonate Aquifer (LCA) and the biosphere. Our oversight and completed Cooperative Agreement research, and a number of other investigators research indicate that there is groundwater flow between the alluvial and carbonate aquifers both at Yucca Mountain and in Inyo County. In addition to the potential of radionuclide transport through the LCA, Czarnecki (1997), with the US Geological Survey, research indicate potential radionuclide transport through the shallower Tertiary-age aquifer materials with ultimate discharge into the Franklin Lake Playa in Inyo County. The specific purpose of this Cooperative Agreement drilling program was to acquire geological, subsurface geology, and hydrologic data to: (1) establish the existence of inter-basin flow between the Amargosa Basin and Death Valley Basin; (2) characterize groundwater flow paths in the LCA through Southern Funeral Mountain Range, and (3) Evaluation the hydraulic connection between the Yucca Mountain repository and the major springs in Death Valley through the LCA

Diversity of inland valleys and opportunities for agricultural development in Sierra Leone.

Directory of Open Access Journals (Sweden)

Elliott Ronald Dossou-Yovo

Full Text Available Inland valleys are becoming increasingly important agricultural production areas for rural households in sub-Saharan Africa due to their relative high and secure water availability and soil fertility. In addition, inland valleys are important as water buffer and biodiversity hot spots and they provide local communities with forest, forage, and fishing resources. As different inland-valley ecosystem functions may conflict with agricultural objectives, indiscriminate development should be avoided. This study aims to analyze the diversity of inland valleys in Sierra Leone and to develop guidelines for more precise interventions. Land use, biophysical and socio-economic data were analyzed on 257 inland valleys using spatial and multivariate techniques. Five cluster groups of inland valleys were identified: (i semi-permanently flooded with high soil organic carbon (4.2% and moderate available phosphorus (10.2 ppm, mostly under natural vegetation; (ii semi-permanently flooded with low soil organic carbon (1.5% and very low available phosphorus (3.1 ppm, abandoned by farmers; (iii seasonally flooded with moderate soil organic carbon (3.1% and low available phosphorus (8.3 ppm, used for rainfed rice and off-season vegetables produced without fertilizer application for household consumption and market; (iv well drained with moderate soil organic carbon (3.8% and moderate available phosphorus (10.0 ppm, used for rainfed rice and off-season vegetables produced with fertilizer application for household consumption and market; and (v well drained with moderate soil organic carbon (3.6% and moderate available phosphorus (11 ppm, used for household consumption without fertilizer application. Soil organic carbon, available phosphorus, hydrological regime, physical accessibility and market opportunity were the major factors affecting agricultural intensification of inland valleys. Opening up the areas in which inland valleys occur through improved roads and

A valley-filtering switch based on strained graphene.

Science.gov (United States)

Zhai, Feng; Ma, Yanling; Zhang, Ying-Tao

2011-09-28

We investigate valley-dependent transport through a graphene sheet modulated by both the substrate strain and the fringe field of two parallel ferromagnetic metal (FM) stripes. When the magnetizations of the two FM stripes are switched from the parallel to the antiparallel alignment, the total conductance, valley polarization and valley conductance excess change greatly over a wide range of Fermi energy, which results from the dependence of the valley-related transmission suppression on the polarity configuration of inhomogeneous magnetic fields. Thus the proposed structure exhibits the significant features of a valley-filtering switch and a magnetoresistance device.

A valley-filtering switch based on strained graphene

International Nuclear Information System (INIS)

Zhai Feng; Ma Yanling; Zhang Yingtao

2011-01-01

We investigate valley-dependent transport through a graphene sheet modulated by both the substrate strain and the fringe field of two parallel ferromagnetic metal (FM) stripes. When the magnetizations of the two FM stripes are switched from the parallel to the antiparallel alignment, the total conductance, valley polarization and valley conductance excess change greatly over a wide range of Fermi energy, which results from the dependence of the valley-related transmission suppression on the polarity configuration of inhomogeneous magnetic fields. Thus the proposed structure exhibits the significant features of a valley-filtering switch and a magnetoresistance device. (paper)

Groundwater model of the Great Basin carbonate and alluvial aquifer system version 3.0: Incorporating revisions in southwestern Utah and east central Nevada

Science.gov (United States)

Brooks, Lynette E.

2017-12-01

The groundwater model described in this report is a new version of previously published steady-state numerical groundwater flow models of the Great Basin carbonate and alluvial aquifer system, and was developed in conjunction with U.S. Geological Survey studies in Parowan, Pine, and Wah Wah Valleys, Utah. This version of the model is GBCAAS v. 3.0 and supersedes previous versions. The objectives of the model for Parowan Valley were to simulate revised conceptual estimates of recharge and discharge, to estimate simulated aquifer storage properties and the amount of reduction in storage as a result of historical groundwater withdrawals, and to assess reduction in groundwater withdrawals necessary to mitigate groundwater-level declines in the basin. The objectives of the model for the area near Pine and Wah Wah Valleys were to recalibrate the model using new observations of groundwater levels and evapotranspiration of groundwater; to provide new estimates of simulated recharge, hydraulic conductivity, and interbasin flow; and to simulate the effects of proposed groundwater withdrawals on the regional flow system. Meeting these objectives required the addition of 15 transient calibration stress periods and 14 projection stress periods, aquifer storage properties, historical withdrawals in Parowan Valley, and observations of water-level changes in Parowan Valley. Recharge in Parowan Valley and withdrawal from wells in Parowan Valley and two nearby wells in Cedar City Valley vary for each calibration stress period representing conditions from March 1940 to November 2013. Stresses, including recharge, are the same in each stress period as in the steady-state stress period for all areas outside of Parowan Valley. The model was calibrated to transient conditions only in Parowan Valley. Simulated storage properties outside of Parowan Valley were set the same as the Parowan Valley properties and are not considered calibrated. Model observations in GBCAAS v. 3.0 are

Hydrology and geochemistry of carbonate springs in Mantua Valley, northern Utah

Science.gov (United States)

Rice, Karen C.; Spangler, Lawrence E.; Spangler, Lawrence E.; Allen, Constance J.

1999-01-01

Water chemistry, tritium data, precipitation-discharge relations, geology, topography, and dye tracing were used to determine recharge areas, ground-water residence times, factors influencing ground-water flow, and aquifer characteristic for five springs that discharge from Paleozoic limestones and dolostones along the margin of Manuta Valley, northern Utah.Temperature of Mantua Valley spring water ranged between 6.0 and 15.0 degrees Celsius. Spring-water temperature indicates that depth of circulation of ground water could be as shallow as 80 feet (25 meters) to as much as 1,150 feet (350 meters). Dissolved-solids concentration in the water from springs ranged from 176 to 268 milligrams per liter. Average total hardness of spring water ranged from 157 to 211 milligrams per liter. Water from all of the springs is a calcium-magnesium-bicarbonate type that generally is undersaturated with respect to calcite and dolomite. The molar calcium/magnesium ratio in spring water ranged from 1.21 to 1.88, and indicates that ground water flows through impure dolostone or a mixed limestone and dolostone terrace.Discharge from carbonate springs in Mantua Valley ranges from about to 10 to 4,300 gallons per minute (0.6 to 271 liters per second). Seasonal variations in chemical parameters and discharge indicate that the aquifers supplying water to most of these springs are predominantly diffuse-flow systems that have been locally enhanced by bedrock dissolution. Estimated recharge area for th springs ranges from 2.7 to 7 square miles (7 to 18 square kilometers).On the basis of tritium age dating, the mean residence time of ground water discharges from Olsens-West Hallins and Maple Springs was determined to be from 3 to 9, and from 4 to 15 years, respectively. Dye tracing from point sources 2.65 miles (4.26 kilometers) southeast of Maple Spring, however, indicates a substantially faster component of flow during snowmelt runoff, with a travel time of about 5 days, or an average ground

The lakes of the Jordan Rift Valley

International Nuclear Information System (INIS)

Gat, J.R.

2001-01-01

This paper presents a summary of the proceedings of a workshop on the Lakes of the Jordan Rift Valley that was held in conjunction with the CRP on The Use of Isotope Techniques in Lake Dynamics Investigations. The paper presents a review of the geological, hydrogeological and physical limnological setting of the lakes in the Jordan Rift Valley, Lake Hula, Lake Kinneret and the Dead Sea. This is complemented by a description of the isotope hydrology of the system that includes the use of a wide range of isotopes: oxygen-18, deuterium, tritium, carbon-14, carbon-13, chlorine isotopes, boron-11 and helium-3/4. Environmental isotope aspects of the salt balances of the lakes, their palaeolimnology and biogeochemical tracers are also presented. The scope of application of isotopic tracers is very broad and provides a clear insight into many aspects of the physical, chemical and biological limnology of the Rift Valley Lakes. (author)

Episodic Late Holocene dune movements on the sand-sheet area, Great Sand Dunes National Park and Preserve, San Luis Valley, Colorado, USA

Science.gov (United States)

Forman, S. L.; Spaeth, M.; Marín, L.; Pierson, J.; Gómez, J.; Bunch, F.; Valdez, A.

2006-07-01

The Great Sand Dunes National Park and Preserve (GSDNPP) in the San Luis Valley, Colorado, contains a variety of eolian landforms that reflect Holocene drought variability. The most spectacular is a dune mass banked against the Sangre de Cristo Mountains, which is fronted by an extensive sand sheet with stabilized parabolic dunes. Stratigraphic exposures of parabolic dunes and associated luminescence dating of quartz grains by single-aliquot regeneration (SAR) protocols indicate eolian deposition of unknown magnitude occurred ca. 1290-940, 715 ± 80, 320 ± 30, and 200-120 yr ago and in the 20th century. There are 11 drought intervals inferred from the tree-ring record in the past 1300 yr at GSDNPP potentially associated with dune movement, though only five eolian depositional events are currently recognized in the stratigraphic record. There is evidence for eolian transport associated with dune movement in the 13th century, which may coincide with the "Great Drought", a 26-yr-long dry interval identified in the tree ring record, and associated with migration of Anasazi people from the Four Corners areas to wetter areas in southern New Mexico. This nascent chronology indicates that the transport of eolian sand across San Luis Valley was episodic in the late Holocene with appreciable dune migration in the 8th, 10-13th, and 19th centuries, which ultimately nourished the dune mass against the Sangre de Cristo Mountains.

Isotopes and Sustainability of the Shallow Groundwater System in Spring and Snake Valleys, Eastern White Pine County, Nevada

Science.gov (United States)

Acheampong, S. Y.

2007-12-01

A critical component to managing water resources is understanding the source of ground water that is extracted from a well. Detail information on the source of recharge and the age of groundwater is thus vital for the proper assessment, development, management, and monitoring of the groundwater resources in an area. Great differences in the isotopic composition of groundwater in a basin and the basin precipitation imply that the groundwater in the basin originates from a source outside the basin or is recharged under different climatic conditions. The stable isotopes of oxygen and hydrogen in precipitation were compared with the isotopic composition of water from wells, springs, and creeks to evaluate the source of the shallow groundwater recharge in Spring and Snake Valleys, Nevada, as part of an evaluation of the water resources in the area. Delta deuterium and delta oxygen-18 composition of springs, wells, creeks, and precipitation in Spring and Snake Valleys show that groundwater recharge occurs primarily from winter precipitation in the surrounding mountains. The carbon-14 content of the groundwater ranged from 30 to 95 percent modern carbon (pmc). Twenty two of the thirty samples had carbon-14 values of greater than 50 pmc. The relatively high carbon-14 values suggest that groundwater in the area is recharged by modern precipitation and the waters have rapid travel times. Total dissolved solids content of the samples outside the playa areas are generally low, and suggests that the water has a relatively short travel time between the recharge areas and sample sites. The presence of tritium in some of the springs and wells also indicate that groundwater mixes with post 1952 precipitation. Hydrogen bomb tests which began in 1952 in the northern hemisphere added large amounts of tritium to the atmosphere and reached a peak in 1963. The stable isotopic composition, the high carbon-14 activities, and the presence of tritium, show that the shallow groundwater in

Hydrogeology and water quality of the West Valley Creek Basin, Chester County, Pennsylvania

Science.gov (United States)

Senior, Lisa A.; Sloto, Ronald A.; Reif, Andrew G.

1997-01-01

The West Valley Creek Basin drains 20.9 square miles in the Piedmont Physiographic Province of southeastern Pennsylvania and is partly underlain by carbonate rocks that are highly productive aquifers. The basin is undergoing rapid urbanization that includes changes in land use and increases in demand for public water supply and wastewater disposal. Ground water is the sole source of supply in the basin.West Valley Creek flows southwest in a 1.5-mile-wide valley that is underlain by folded and faulted carbonate rocks and trends east-northeast, parallel to regional geologic structures. The valley is flanked by hills underlain by quartzite and gneiss to the north and by phyllite and schist to the south. Surface water and ground water flow from the hills toward the center of the valley. Ground water in the valley flows west-southwest parallel to the course of the stream. Seepage investigations identified losing reaches in the headwaters area where streams are underlain by carbonate rocks and gaining reaches downstream. Tributaries contribute about 75 percent of streamflow. The ground-water and surface-water divides do not coincide in the carbonate valley. The ground-water divide is about 0.5 miles west of the surface-water divide at the eastern edge of the carbonate valley. Underflow to the east is about 1.1 inches per year. Quarry dewatering operations at the western edge of the valley may act partly as an artificial basin boundary, preventing underflow to the west. Water budgets for 1990, a year of normal precipitation (45.8 inches), and 1991, a year of sub-normal precipitation (41.5 inches), were calculated. Streamflow was 14.61 inches in 1990 and 12.08 inches in 1991. Evapotranspiration was estimated to range from 50 to 60 percent of precipitation. Base flow was about 62 percent of streamflow in both years. Exportation by sewer systems was about 3 inches from the basin and, at times, equaled base flow during the dry autumn of 1991. Recharge was estimated to be 18

Revolution in The Valley The Insanely Great Story of How the Mac Was Made

CERN Document Server

Hertzfeld, Andy

2011-01-01

There was a time, not too long ago, when the typewriter and notebook ruled, and the computer as an everyday tool was simply a vision. Revolution in the Valley traces this vision back to its earliest roots: the hallways and backrooms of Apple, where the groundbreaking Macintosh computer was born. The book traces the development of the Macintosh, from its inception as an underground skunkworks project in 1979 to its triumphant introduction in 1984 and beyond. The stories in Revolution in the Valley come on extremely good authority. That's because author Andy Hertzfeld was a core member of the

Makran Mountain Range, Indus River Valley, Pakistan, India

Science.gov (United States)

1984-01-01

The enormous geologic pressures exerted by continental drift can be very well illustrated by the long northward curving parallel folded mountain ridges and valleys of the coastal Makran Range of Pakistan (27.0N, 66.0E). As a result of the collision of the northward bound Indian sub-continent into the Asian Continent, the east/west parallel range has been bent in a great northward arc and forming the Indus River valley at the interface of the collision.

Modeling the long-term fate of agricultural nitrate in groundwater in the San Joaquin Valley, California

Science.gov (United States)

Chapelle, Francis H.; Campbell, Bruce G.; Widdowson, Mark A.; Landon, Mathew K.

2013-01-01

Nitrate contamination of groundwater systems used for human water supplies is a major environmental problem in many parts of the world. Fertilizers containing a variety of reduced nitrogen compounds are commonly added to soils to increase agricultural yields. But the amount of nitrogen added during fertilization typically exceeds the amount of nitrogen taken up by crops. Oxidation of reduced nitrogen compounds present in residual fertilizers can produce substantial amounts of nitrate which can be transported to the underlying water table. Because nitrate concentrations exceeding 10 mg/L in drinking water can have a variety of deleterious effects for humans, agriculturally derived nitrate contamination of groundwater can be a serious public health issue. The Central Valley aquifer of California accounts for 13 percent of all the groundwater withdrawals in the United States. The Central Valley, which includes the San Joaquin Valley, is one of the most productive agricultural areas in the world and much of this groundwater is used for crop irrigation. However, rapid urbanization has led to increasing groundwater withdrawals for municipal public water supplies. That, in turn, has led to concern about how contaminants associated with agricultural practices will affect the chemical quality of groundwater in the San Joaquin Valley. Crop fertilization with various forms of nitrogen-containing compounds can greatly increase agricultural yields. However, leaching of nitrate from soils due to irrigation has led to substantial nitrate contamination of shallow groundwater. That shallow nitrate-contaminated groundwater has been moving deeper into the Central Valley aquifer since the 1960s. Denitrification can be an important process limiting the mobility of nitrate in groundwater systems. However, substantial denitrification requires adequate sources of electron donors in order to drive the process. In many cases, dissolved organic carbon (DOC) and particulate organic carbon

2D Semiconductors for Valley-Polarized LEDs and Photodetectors

Science.gov (United States)

Yu, Ting

The recently discovered two-dimensional (2D) semiconductors, such as transitional-metal-dichalcogenide monolayers, have aroused great interest due to the underlying quantum physics and the appealing optoelectronic applications like atomically thin light-emitting diodes (LEDs) and photodetectors. On the one hand, valley-polarized electroluminescence and photocurrent from such monolayers have not caused enough attention but highly demanded as building blocks for the new generation valleytronic applications. On the other hand, most reports on these devices are based on the mechanically exfoliated small samples. Considering real applications, a strategy which could offer mass-product and high compatibility to the current planar processes is greatly demanded. Large-area samples prepared by chemical vapour deposition (CVD) are perfect candidates towards such a goal. Here, we report electrically tunable valley-polarized electroluminescence and the selective spin-valley-coupled photocurrent in optoelectronic devices based on monolayer WS2 and MoS2 grown by CVD, exhibiting large electroluminescence and photocurrent dichroisms of 81% and 60%, respectively. The controllable valley polarization and emission components of the electroluminescence have been realized by varying electrical injection of carriers. For the observed helicity-dependent photocurrent, the circular photogalvanic effect at resonant excitations has been found to take the dominant responsibility.

Stable carbon isotopes as an indicator for soil degradation in an alpine environment (Urseren Valley, Switzerland).

Science.gov (United States)

Schaub, Monika; Alewell, Christine

2009-05-01

Analyses of soil organic carbon (SOC) content and stable carbon isotope signatures (delta(13)C) of soils were assessed for their suitability to detect early stage soil erosion. We investigated the soils in the alpine Urseren Valley (southern central Switzerland) which are highly impacted by soil erosion. Hill slope transects from uplands (cambisols) to adjacent wetlands (histosols and histic to mollic gleysols) differing in their intensity of visible soil erosion, and reference wetlands without erosion influence were sampled. Carbon isotopic signature and SOC content of soil depth profiles were determined. A close correlation of delta(13)C and carbon content (r > 0.80) is found for upland soils not affected by soil erosion, indicating that depth profiles of delta(13)C of these upland soils mainly reflect decomposition of SOC. Long-term disturbance of an upland soil is indicated by decreasing correlation of delta(13)C and SOC (r soil erosion in hill slope transects from uplands to adjacent wetlands is documented as an intermediate delta(13)C value (-27.5 per thousand) for affected wetland soil horizons (0-12 cm) between upland (aerobic metabolism, relatively heavier delta(13)C of -26.6 per thousand) and wetland isotopic signatures (anaerobic metabolism, relatively lighter delta(13)C of -28.6 per thousand). Carbon isotopic signature and SOC content are found to be sensitive indicators of short- and long-term soil erosion processes. Copyright (c) 2009 John Wiley & Sons, Ltd.

Seismicity related to geothermal development in Dixie Valley, Nevada

Energy Technology Data Exchange (ETDEWEB)

Ryall, A.S.; Vetter, U.R.

1982-07-08

A ten-station seismic network was operated in and around the Dixie Valley area from January 1980 to November 1981; three of these stations are still in operation. Data from the Dixie Valley network were analyzed through 30 Jun 1981, and results of analysis were compared with analysis of somewhat larger events for the period 1970-1979. The seismic cycle in the Western Great Basic, the geologic structural setting, and the instrumentation are also described.

Seasonal and diurnal variations of methane and carbon dioxide in the highly polluted Kathmandu Valley, Nepal

Science.gov (United States)

Mahata, Khadak; Panday, Arnico; Rupakheti, Maheswar; Lawrence, Mark

2016-04-01

Anthropogenic emissions of carbon dioxide and methane - key greenhouse gases (GHGs) - are primary causes of global warming and resultant impacts. The atmospheric warming is more pronounced and likely to cause more serious damage in vulnerable areas such as the Hindukush-Karakorum-Himalayan region (HKH). The HKH region is a data gap region according to the 5th Assessment report of the intergovernmental panel on climate change (IPCC). In order to understand the mixing ratios and variability of the key GHGs in the foothills of the Central Himalaya, we carried out continuous measurements of CO2, CH4, CO, and water vapor at Bode (an urban site in the Kathmandu valley, Nepal) for a year (March 2013 - Feb 2014), and again at Bode and at Chanban (a background outside the Valley) for 3 months (July 15 - Oct 3, 2015), with two state-of-the-art cavity ring-down instruments (Picarro G2401). The measurements were carried out as a part of the international air pollution measurement campaign: SusKat- ABC (Sustainable atmosphere for the Kathmandu Valley - Atmospheric Brown Clouds). The annual average CO2 and CH4 concentrations at Bode were 419 ± 24 and 2.192 ± 0.224 ppm, respectively, which are notably higher than those observed at the background site at Mauna Loa Observatory in the same period. The CO2concentration at Bode was high during the pre-monsoon period and low during the monsoon, while CH4 was high in winter and lower during the pre-monsoon period. The monthly CO2concentration was highest in April. Forest fires and agro-waste burning in the region, and the local emissions in the Kathmandu valley were the main sources of the high CO2 in the pre-monsoon period. CH4 showed a maximum in September due to additional emissions from paddy fields. Seasonally, winter has the highest CH4 concentration which is due to brick production, which is a seasonal activity, and other local sources combined with the shallow mixing layer height in winter. The diurnal pattern of CO2 and CH4

High pollution events in the Great Salt Lake Basin and its adjacent valleys. Insights on mechanisms and spatial distribution of the formation of secondary aerosol.

Science.gov (United States)

Franchin, A.; Middlebrook, A. M.; Baasandorj, M.; Brown, S. S.; Fibiger, D. L.; Goldberger, L.; McDuffie, E. E.; Moravek, A.; Murphy, J. G.; Thornton, J. A.; Womack, C.

2017-12-01

High pollution events are common in many locations in the U.S.A. and around the world. They can last several days or up to weeks and they negatively affect human health, deteriorate visibility, and increase premature mortality. The main causes for high pollution events are related to meteorology and sources. They often happen in the winter, when high emissions, stagnation and reduced mixing, due to a shallow boundary layer, cause high concentrations of pollutants to accumulate. In the last decades, the air quality in the U.S. has seen an overall improvement, due to the reductions in particulate and gaseous pollutants. However, some areas remain critical. The Great Salt Lake Basin and its adjacent valleys are currently areas where high pollution events are a serious environmental problem involving more than 2.4 million people. We will present the results of the Utah Wintertime Fine Particulate Study (UWFPS) that took place in winter 2017. During UWFPS, we carried out airborne measurements of aerosol chemical composition and precursor vapor concentrations over the Great Salt Lake Basin and its adjacent valleys. We will give insights into how and under which conditions conversion of precursor vapors into aerosol particles takes place in the area. We will also present a comparison of our measurements with models that will provide an insight of the mechanisms that lead to the formation of secondary aerosol particles. With the results of our work, we aim to inform strategies for pollution control in the future.

Clean Cities Award Winning Coalition: Coachella Valley

Energy Technology Data Exchange (ETDEWEB)

ICF Kaiser

1999-05-20

Southern California's Coachella Valley became a Clean Cities region in 1996. Since then, they've made great strides. SunLine Transit, the regional public transit provider, was the first transit provider to replace its entire fleet with compressed natural gas buses. They've also built the foundation for a nationally recognized model in the clean air movement, by partnering with Southern California Gas Company to install a refueling station and developing a curriculum for AFV maintenance with the College of the Desert. Today the valley is home to more than 275 AFVs and 15 refueling stations.

Enhanced valley splitting in monolayer WSe2 due to magnetic exchange field.

Science.gov (United States)

Zhao, Chuan; Norden, Tenzin; Zhang, Peiyao; Zhao, Puqin; Cheng, Yingchun; Sun, Fan; Parry, James P; Taheri, Payam; Wang, Jieqiong; Yang, Yihang; Scrace, Thomas; Kang, Kaifei; Yang, Sen; Miao, Guo-Xing; Sabirianov, Renat; Kioseoglou, George; Huang, Wei; Petrou, Athos; Zeng, Hao

2017-08-01

Exploiting the valley degree of freedom to store and manipulate information provides a novel paradigm for future electronics. A monolayer transition-metal dichalcogenide (TMDC) with a broken inversion symmetry possesses two degenerate yet inequivalent valleys, which offers unique opportunities for valley control through the helicity of light. Lifting the valley degeneracy by Zeeman splitting has been demonstrated recently, which may enable valley control by a magnetic field. However, the realized valley splitting is modest (∼0.2 meV T -1 ). Here we show greatly enhanced valley spitting in monolayer WSe 2 , utilizing the interfacial magnetic exchange field (MEF) from a ferromagnetic EuS substrate. A valley splitting of 2.5 meV is demonstrated at 1 T by magnetoreflectance measurements and corresponds to an effective exchange field of ∼12 T. Moreover, the splitting follows the magnetization of EuS, a hallmark of the MEF. Utilizing the MEF of a magnetic insulator can induce magnetic order and valley and spin polarization in TMDCs, which may enable valleytronic and quantum-computing applications.

Quantum transport in carbon nanotubes

DEFF Research Database (Denmark)

Laird, Edward A.; Kuemmeth, Ferdinand; Steele, Gary A.

2015-01-01

Carbon nanotubes are a versatile material in which many aspects of condensed matter physics come together. Recent discoveries, enabled by sophisticated fabrication, have uncovered new phenomena that completely change our understanding of transport in these devices, especially the role of the spin...... blockade. This can be exploited to read out spin and valley qubits, and to measure the decay of these states through coupling to nuclear spins and phonons. A second unique property of carbon nanotubes is that the combination of valley freedom and electron-electron interactions in one dimension strongly...... and valley degrees of freedom. This review describes the modern understanding of transport through nanotube devices. Unlike conventional semiconductors, electrons in nanotubes have two angular momentum quantum numbers, arising from spin and from valley freedom. We focus on the interplay between the two...

Holocene millennial to centennial scale carbonate cycles (leeward margin, Great Bahama Bank)

Science.gov (United States)

Roth, S.; Reijmer, J. J. G.

2003-04-01

The main research topic of this project is the evaluation of Holocene to Recent climatic variability and the impact on shallow-water sediment production of carbonate platforms. A 38m long sediment core (MD992201) was analyzed, obtained from 290m water depth on the leeward margin of Great Bahama Bank. Fourteen Accelerator Mass Spectrometry (AMS) dates determined a core bottom age of 7,230 years BP and permitted the construction of a precise time frame. With a sampling interval of 5cm, a decadal time resolution could be achieved. Sedimentation rates varied between 3 to 14m/kyr. Carbonate content ranges from 96 to almost 100wt%, most of which is aragonite (83-92wt%). High Magnesium Calcite (HMC) makes up the second major fraction with 2-9wt%, while Low Magnesium Calcite occurs with minor percentages (0.5-4wt%). Singular Spectrum Analysis (SSA) of the aragonitic carbonate phase showed two different trends and two primary oscillatory signals. Aragonite production on Great Bahama Bank started at 7,230yr BP when the Holocene sea-level rise flooded the shallow platform top. The first eigenvector captures this long-term trend extending over the entire Mid to Late Holocene succession displaying the Holocene sea-level fluctuations. The second trend indicates millennial scale variations, which can be attributed to a combination of geomagnetic shielding and solar parameters. The two quasi-periodic signals show wavelengths of 400-600 years and approx. 210 years. These oscillations are interpreted in terms of instabilities of the thermohaline circulation and solar parameters, respectively. The oscillatory aragonite signals and oxygen isotope derived temperatures (planktonic foraminifers) agree with northern hemisphere temperature changes (e.g. Medieval Warm Period and Little Ice Age) and the delta-14C record of tree rings (e.g. Oort to Dalton solar minima). This study shows that carbonate platform systems not only respond to sea-level variations but also are precise recorders of

Systematically variable planktonic carbon metabolism along a land-to-lake gradient in a Great Lakes coastal zone.

Science.gov (United States)

Weinke, Anthony D; Kendall, Scott T; Kroll, Daniel J; Strickler, Eric A; Weinert, Maggie E; Holcomb, Thomas M; Defore, Angela A; Dila, Deborah K; Snider, Michael J; Gereaux, Leon C; Biddanda, Bopaiah A

2014-11-01

During the summers of 2002-2013, we measured rates of carbon metabolism in surface waters of six sites across a land-to-lake gradient from the upstream end of drowned river-mouth Muskegon Lake (ML) (freshwater estuary) to 19 km offshore in Lake Michigan (LM) (a Great Lake). Despite considerable inter-year variability, the average rates of gross production (GP), respiration (R) and net production (NP) across ML (604 ± 58, 222 ± 22 and 381 ± 52 µg C L -1 day -1 , respectively) decreased steeply in the furthest offshore LM site (22 ± 3, 55 ± 17 and -33 ± 15 µg C L -1 day -1 , respectively). Along this land-to-lake gradient, GP decreased by 96 ± 1%, whereas R only decreased by 75 ± 9%, variably influencing the carbon balance along this coastal zone. All ML sites were consistently net autotrophic (mean GP:R = 2.7), while the furthest offshore LM site was net heterotrophic (mean GP:R = 0.4). Our study suggests that pelagic waters of this Great Lakes coastal estuary are net carbon sinks that transition into net carbon sources offshore. Reactive and dynamic estuarine coastal zones everywhere may contribute similarly to regional and global carbon cycles.

Impacts of climatic and atmospheric changes on carbon dynamics in the Great Smoky Mountains National Park

International Nuclear Information System (INIS)

Zhang Chi; Tian Hanqin; Chappelka, Arthur H.; Ren Wei; Chen Hua; Pan Shufen; Liu Mingliang; Styers, Diane M.; Chen Guangsheng; Wang Yuhang

2007-01-01

We used the Dynamic Land Ecosystem Model (DLEM) to estimate carbon (C) storage and to analyze the impacts of environmental changes on C dynamics from 1971 to 2001 in Great Smoky Mountain National Park (GRSM). Our simulation results indicate that forests in GRSM have a C density as high as 15.9 kg m -2 , about twice the regional average. Total carbon storage in GRSM in 2001 was 62.2 Tg (T = 10 12 ), 54% of which was in vegetation, the rest in the soil detritus pool. Higher precipitation and lower temperatures in the higher elevation forests result in larger total C pool sizes than in forests at lower elevations. During the study period, the CO 2 fertilization effect dominated ozone and climatic stresses (temperature and precipitation), and the combination of these multiple factors resulted in net accumulation of 0.9 Tg C in this ecosystem. - Model simulations suggest that rising atmospheric CO 2 compensates for the adverse effects of ozone stress on ecosystem carbon dynamics in Great Smoky Mountain National Park

Generation and electric control of spin-valley-coupled circular photogalvanic current in WSe2

Science.gov (United States)

Yuan, Hongtao; Hwang, Harold Y.; Cui, Yi

2015-03-01

Compared to the weak spin-orbit-interaction (SOI) in graphene, layered transitionmetal chalcogenides MX2 have heavy 4d/5d elements with strong atomic SOI, providing a unique way to extend functionalities of novel spintronics and valleytronics devices. Such a valley polarization achieved via valley-selective circular dichroism has been predicted theoretically and demonstrated with optical experiments in MX2 systems. Despite the exciting progresses, the generation of a valley/spin current by valley polarization in MX2 remains elusive and a great challenge. A spin/valley current in MX2 compounds caused by such a valley polarization has never been observed, nor its electric-field control. In this talk, we demonstrated, within an electric-double-layer transistor based on WSe2, the manipulation of a spin-coupled valley photocurrent whose direction and magnitude depend on the degree of circular polarization of the incident radiation and can be further greatly modulated with an external electric field. Such room temperature generation and electric control of valley/spin photocurrent provides a new property of electrons in MX2 systems, thereby enabling new degrees of control for quantum-confined spintronics devices. (In collaboration with S.C. Zhang, Y.L. Chen, Z.X. Shen, B Lian, H.J. Zhang, G Xu, Y Xu, B Zhou, X.Q. Wang, B Shen X.F. Fang) Acknowledge the support from DoE, BES, Division of MSE under contract DE-AC02-76SF00515. Acknowledge the support from DoE, BES, Division of MSE under contract DE-AC02-76SF00515.

Radiation processing of temperate fruits of Kashmir valley

International Nuclear Information System (INIS)

Hussain, Peerzada R.; Meena, Raghuveer S.; Dar, Mohd A.; Wani, Ali M.

2011-01-01

Kashmir valley is famous for its temperate horticulture. Main temperate fruits grown commercially in the valley include apple, pear, peach, plum, cherry, strawberry and apricot. These fruits being perishable and susceptible to microbial spoilage, have a short shelf-life. The short shelf-life in an impediment in their transportation and marketing and results in huge losses. Study was carried out at NRL, Srinagar to investigate the effect of gamma irradiation on the keeping quality of most of these fruits. The effect of gamma irradiation alone and in combination with other techniques like controlled low temperature storage, edible polysaccharide coating and calcium chloride treatment was studied in detail. The results revealed that there is a great potential for the use of radiation in extending the storage life of most of the temperate fruits produced in the valley of Kashmir. (author)

Regolith transport in the Dry Valleys of Antarctica

Science.gov (United States)

Putkonen, J.; Rosales, M.; Turpen, N.; Morgan, D.; Balco, G.; Donaldson, M.

2007-01-01

The stability of ground surface and preservation of landforms that record past events and environments is of great importance as the geologic and climatic history is evaluated in the Dry Valleys of Antarctica. Currently little is known about the regolith transport that tends to eradicate and confound this record and regolith transport is itself an environmental indicator. Based on analyses of repeat photographs, soil traps, and pebble transport distances, it was found that there is a large spatial variation in topographic diffusivities at least in the annual basis and that counter intuitively the highest topographic diffusivities are found in the alpine valleys that are located farther inland from the coast where the lowest topographic diffusivities were recorded. An average topographic diffusivity for the Dry Valleys was determined to be 10M-5–10-4 m2

Timing of Mississippi Valley-type mineralization: Relation to Appalachian orogenic events

Energy Technology Data Exchange (ETDEWEB)

Kesler, S.E.; van der Pluijm, B.A. (Univ. of Michigan, Ann Arbor (USA))

1990-11-01

Although Mississippi Valley-type deposits in Lower Ordovician carbonate rocks of the Appalachian orogen are commonly interpreted to have been precipitated by basinal brines, the timing of brine migration remains poorly known. Late Paleozoic K-Ar isotopic ages on authigenic K-feldspar, which is widespread in Appalachian carbonate rocks, as well as evidence of paleomagnetic overprints of similar age, have focused attention on the possibility that these Mississippi Valley-type deposits formed as a result of late Paleozoic deformation. Geologic and geochemical similarities among most of these deposits, from Georgia to Newfoundland, including unusually high sphalerite/galena ratios, isotopically heavy sulfur, and relatively nonradiogenic lead, suggest that they are coeval. Sphalerite sand that parallels host-rock layering in many of the deposits indicates that mineralization occurred before regional deformation. Although the late Paleozoic age of deformation in the southern Appalachians provides little constraint on the age of Mississippi Valley-type mineralization, deformation of these deposits in the Newfoundland Appalachians is early to middle Paleozoic in age. Thus, if Ordovician-hosted, Appalachian Mississippi Valley-type deposits are coeval, they must have formed by middle Paleozoic time and cannot be the product of a late Paleozoic fluid-expulsion event. This hypothesis has important implications for basin evolution, fluid events, and remagnetization in the Appalachians.

Seasonal and diurnal variations in methane and carbon dioxide in the Kathmandu Valley in the foothills of the central Himalayas

Science.gov (United States)

Singh Mahata, Khadak; Panday, Arnico Kumar; Rupakheti, Maheswar; Singh, Ashish; Naja, Manish; Lawrence, Mark G.

2017-10-01

The SusKat-ABC (Sustainable Atmosphere for the Kathmandu Valley-Atmospheric Brown Clouds) international air pollution measurement campaign was carried out from December 2012 to June 2013 in the Kathmandu Valley and surrounding regions in Nepal. The Kathmandu Valley is a bowl-shaped basin with a severe air pollution problem. This paper reports measurements of two major greenhouse gases (GHGs), methane (CH4) and carbon dioxide (CO2), along with the pollutant CO, that began during the campaign and were extended for 1 year at the SusKat-ABC supersite in Bode, a semi-urban location in the Kathmandu Valley. Simultaneous measurements were also made during 2015 in Bode and a nearby rural site (Chanban) ˜ 25 km (aerial distance) to the southwest of Bode on the other side of a tall ridge. The ambient mixing ratios of methane (CH4), carbon dioxide (CO2), water vapor, and carbon monoxide (CO) were measured with a cavity ring-down spectrometer (G2401; Picarro, USA) along with meteorological parameters for 1 year (March 2013-March 2014). These measurements are the first of their kind in the central Himalayan foothills. At Bode, the annual average mixing ratios of CO2 and CH4 were 419.3 (±6.0) ppm and 2.192 (±0.066) ppm, respectively. These values are higher than the levels observed at background sites such as Mauna Loa, USA (CO2: 396.8 ± 2.0 ppm, CH4: 1.831 ± 0.110 ppm) and Waliguan, China (CO2: 397.7 ± 3.6 ppm, CH4: 1.879 ± 0.009 ppm) during the same period and at other urban and semi-urban sites in the region, such as Ahmedabad and Shadnagar (India). They varied slightly across the seasons at Bode, with seasonal average CH4 mixing ratios of 2.157 (±0.230) ppm in the pre-monsoon season, 2.199 (±0.241) ppm in the monsoon, 2.210 (±0.200) ppm in the post-monsoon, and 2.214 (±0.209) ppm in the winter season. The average CO2 mixing ratios were 426.2 (±25.5) ppm in the pre-monsoon, 413.5 (±24.2) ppm in the monsoon, 417.3 (±23.1) ppm in the post-monsoon, and 421.9 (±20

Variation of precipitation in Langtang Valley,Himalayas

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

The variation of the δ 18O in precipitation and the relationship with precipitation amountat Kyangjin Base House and Yala Glacier Camp in Langtang Valley, Nepal Himalayas were ana-lyzed. The variations of the δ 18O with precipitation had great scatter, and the correlations betweenthe δ18O and precipitation changed with time on the synoptic scale. On the seasonal scale, therewas marked amount effect at Kyangjin Base House. However, the δ18O-precipitation gradient wassmaller than that on the synoptic scale. Because of the maintenance of the basic equilibrium be-tween stable isotopic compositions in atmospheric vapor and precipitation, the evaporation en-richment was light during the rainy season. Therefore, the variation of stable isotopic compositionsin precipitation was independent on the sampling intervals. Simulations show that the rainfall inLangtang Valley was not the outcome of the initial condensation of ocean vapor that originatedfrom low latitudes. The stable isotopic compositions in precipitation were greatly depleted due tothe strong rainout of the vapor from oceans as the vapor was raised over the Himalayas

Spin-valley dynamics of electrically driven ambipolar carbon-nanotube quantum dots

Science.gov (United States)

Osika, E. N.; Chacón, A.; Lewenstein, M.; Szafran, B.

2017-07-01

An ambipolar n-p double quantum dot defined by potential variation along a semiconducting carbon-nanotube is considered. We focus on the (1e,1h) charge configuration with a single excess electron of the conduction band confined in the n-type dot and a single missing electron in the valence band state of the p-type dot for which lifting of the Pauli blockade of the current was observed in the electric-dipole spin resonance (Laird et al 2013 Nat. Nanotechnol. 8 565). The dynamics of the system driven by periodic electric field is studied with the Floquet theory and the time-dependent configuration interaction method with the single-electron spin-valley-orbitals determined for atomistic tight-binding Hamiltonian. We find that the transitions lifting the Pauli blockade are strongly influenced by coupling to a vacuum state with an empty n dot and a fully filled p dot. The coupling shifts the transition energies and strongly modifies the effective g factors for axial magnetic field. The coupling is modulated by the bias between the dots but it appears effective for surprisingly large energy splitting between the (1e,1h) ground state and the vacuum (0e, 0h) state. Multiphoton transitions and high harmonic generation effects are also discussed.

Hydrogeologic Framework and Ground Water in Basin-Fill Deposits of the Diamond Valley Flow System, Central Nevada

Science.gov (United States)

Tumbusch, Mary L.; Plume, Russell W.

2006-01-01

The Diamond Valley flow system, an area of about 3,120 square miles in central Nevada, consists of five hydrographic areas: Monitor, Antelope, Kobeh, and Diamond Valleys and Stevens Basin. Although these five areas are in a remote part of Nevada, local government officials and citizens are concerned that the water resources of the flow system eventually could be further developed for irrigation or mining purposes or potentially for municipal use outside the study area. In order to better understand the flow system, the U.S. Geological Survey in cooperation with Eureka, Lander, and Nye Counties and the Nevada Division of Water Resources, is conducting a multi-phase study of the flow system. The principal aquifers of the Diamond Valley flow system are in basin-fill deposits that occupy structural basins comprised of carbonate rocks, siliciclastic sedimentary rocks, igneous intrusive rocks, and volcanic rocks. Carbonate rocks also function as aquifers, but their extent and interconnections with basin-fill aquifers are poorly understood. Ground-water flow in southern Monitor Valley is from the valley margins toward the valley axis and then northward to a large area of discharge by evapotranspiration (ET) that is formed south of a group of unnamed hills near the center of the valley. Ground-water flow from northern Monitor Valley, Antelope Valley, and northern and western parts of Kobeh Valley converges to an area of ground-water discharge by ET in central and eastern Kobeh Valley. Prior to irrigation development in the 1960s, ground-water flow in Diamond Valley was from valley margins toward the valley axis and then northward to a large discharge area at the north end of the valley. Stevens Basin is a small upland basin with internal drainage and is not connected with other parts of the flow system. After 40 years of irrigation pumping, a large area of ground-water decline has developed in southern Diamond Valley around the irrigated area. In this part of Diamond

Chiral filtration-induced spin/valley polarization in silicene line defects

Science.gov (United States)

Ren, Chongdan; Zhou, Benhu; Sun, Minglei; Wang, Sake; Li, Yunfang; Tian, Hongyu; Lu, Weitao

2018-06-01

The spin/valley polarization in silicene with extended line defects is investigated according to the chiral filtration mechanism. It is shown that the inner-built quantum Hall pseudo-edge states with identical chirality can serve as a chiral filter with a weak magnetic field and that the transmission process is restrained/strengthened for chiral states with reversed/identical chirality. With two parallel line defects, which act as natural chiral filtration, the filter effect is greatly enhanced, and 100% spin/valley polarization can be achieved.

Understanding the behavior of carbon dioxide and surface energy fluxes in semiarid Salt Lake Valley, Utah, USA

Science.gov (United States)

Ramamurthy, Prathap

This dissertation reports the findings from the Salt Lake Valley flux study. The Salt Lake Valley flux study was designed to improve our understanding of the complex land-atmosphere interactions in urban areas. The flux study used the eddy covariance technique to quantify carbon dioxide and surface energy budget in the semiarid Salt Lake Valley. Apart from quantifying fluxes, the study has also added new insight into the nature of turbulent scalar transport in urban areas and has addressed some of the complications in using Eddy Covariance technique in urban areas. As part of this experiment, eddy fluxes of CO2 and surface energy fluxes were measured at two sites, with distinct urban landforms; One site was located in a suburban neighborhood with substantial vegetative cover, prototypical of many residential neighborhoods in the valley. The other CO2 site was in a preurban surrounding that resembled the Salt Lake Valley before it was urbanized. The two sites were intentionally chosen to illustrate the impact of urbanization on CO 2 and surface energy flux cycles. Results indicate that the suburban site acted as a sink of CO2 during the midday period due to photosynthesis and acted as a source of CO2 during the evening and nighttime periods. The vegetative cover around the suburban site also had a significant impact on the surface energy fluxes. Contribution from latent heat flux was substantially high at the suburban site during the summer months compared to sensible heat. The turbulence investigation found that the general behavior of turbulence was very much influenced by local factors and the statistics did not always obey Monin-Obukhov Similarity parameters. This investigation also found that the scalar (co)spectra observed at the suburban site were characterized by multiple peaks and were different compared to (co)spectra reported over forest and crop canopies. The study also observed multiscale CO2 transport at the suburban site during the convective period

Organic and Elemental Carbon Aerosol Particulates at the Southern Great Plains Site Field Campaign Report

Energy Technology Data Exchange (ETDEWEB)

Cary, Robert

2016-04-01

The purpose of this study was to measure the organic carbon (OC) and elemental carbon (EC) fractions of PM2.5 particulate matter at the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility Southern Great Plains (SGP) sampling site for a 6-month period during the summer of 2013. The site is in a rural location remote from any populated areas, so it would be expected to reflect carbon concentration over long-distance transport patterns. During the same period in 2012, a number of prairie fires in Oklahoma and Texas had produced large plumes of smoke particles, but OC and EC particles had not been quantified. In addition, during the summer months, other wild fires, such as forest fires in the Rocky Mountain states and other areas, can produce carbon aerosols that are transported over long distances. Both of these source types would be expected to contain mixtures of both OC and EC.

Fitness-valley crossing with generalized parent-offspring transmission.

Science.gov (United States)

Osmond, Matthew M; Otto, Sarah P

2015-11-01

Simple and ubiquitous gene interactions create rugged fitness landscapes composed of coadapted gene complexes separated by "valleys" of low fitness. Crossing such fitness valleys allows a population to escape suboptimal local fitness peaks to become better adapted. This is the premise of Sewall Wright's shifting balance process. Here we generalize the theory of fitness-valley crossing in the two-locus, bi-allelic case by allowing bias in parent-offspring transmission. This generalization extends the existing mathematical framework to genetic systems with segregation distortion and uniparental inheritance. Our results are also flexible enough to provide insight into shifts between alternate stable states in cultural systems with "transmission valleys". Using a semi-deterministic analysis and a stochastic diffusion approximation, we focus on the limiting step in valley crossing: the first appearance of the genotype on the new fitness peak whose lineage will eventually fix. We then apply our results to specific cases of segregation distortion, uniparental inheritance, and cultural transmission. Segregation distortion favouring mutant alleles facilitates crossing most when recombination and mutation are rare, i.e., scenarios where crossing is otherwise unlikely. Interactions with more mutable genes (e.g., uniparental inherited cytoplasmic elements) substantially reduce crossing times. Despite component traits being passed on poorly in the previous cultural background, small advantages in the transmission of a new combination of cultural traits can greatly facilitate a cultural transition. While peak shifts are unlikely under many of the common assumptions of population genetic theory, relaxing some of these assumptions can promote fitness-valley crossing. Copyright © 2015 Elsevier Inc. All rights reserved.

Structural controls on the emission of magmatic carbon dioxide gas, Long Valley Caldera, USA

Science.gov (United States)

Lucic, Gregor; Stix, John; Wing, Boswell

2015-04-01

We present a degassing study of Long Valley Caldera that explores the structural controls upon emissions of magmatic carbon dioxide gas. A total of 223 soil gas samples were collected and analyzed for stable carbon isotopes using a field-portable cavity ring-down spectrometer. This novel technique is flexible, accurate, and provides sampling feedback on a daily basis. Sampling sites included major and minor volcanic centers, regional throughgoing faults, caldera-related structures, zones of elevated seismicity, and zones of past and present hydrothermal activity. The classification of soil gases based on their δ13C and CO2 values reveals a mixing relationship among three end-members: atmospheric, biogenic, and magmatic. Signatures dominated by biogenic contributions (~4 vol %, -24‰) are found on the caldera floor, the interior of the resurgent dome, and areas associated with the Hilton Creek and Hartley Springs fault systems. With the introduction of the magmatic component (~100 vol %, -4.5‰), samples acquire mixing and hydrothermal signatures and are spatially associated with the central caldera and Mammoth Mountain. In particular, they are concentrated along the southern margin of the resurgent dome where the interplay between resurgence-related reverse faulting and a bend in the regional fault system has created a highly permeable fracture network, suitable for the formation of shallow hydrothermal systems. This contrasts with the south moat, where despite elevated seismicity, a thick sedimentary cover has formed an impermeable cap, inhibiting the ascent of fluids and gases to the surface.

[Effects of grazing disturbance on soil active organic carbon in mountain forest-arid valley ecotone in the upper reaches of Minjiang River].

Science.gov (United States)

Liu, Shan-Shan; Zhang, Xing-Hua; Gong, Yuan-Bo; Li, Yuan; Wang, Yan; Yin, Yan-Jie; Ma, Jin-Song; Guo, Ting

2014-02-01

Effects of grazing disturbance on the soil carbon contents and active components in the four vegetations, i.e., artificial Robinia pseudoacacia plantation, artificial poplar plantation, Berberis aggregate shrubland and grassland, were studied in the mountain forest-arid valley ecotone in the upper Minjiang River. Soil organic carbon and active component contents in 0-10 cm soil layer were greater than in 10-20 cm soil layer at each level of grazing disturbance. With increasing the grazing intensity, the total organic carbon (TOC), light fraction organic carbon (LFOC), particulate organic carbon (POC) and easily oxidized carbon (LOC) contents in 0-10 cm soil layer decreased gradually in the artificial R. pseudoacacia plantation. The LFOC content decreased, the POC content increased, and the TOC and LOC contents decreased initially and then increased with increasing the grazing intensity in the artificial poplar plantation. The POC content decreased, and the TOC, LFOC and LOC contents decreased initially and then increased with increasing the grazing intensity in the B. aggregate shrubland. The POC and TOC contents decreased, and the LFOC and LOC contents decreased initially and then increased with increasing the grazing intensity in the grassland. The decreasing ranges of LOC, LFOC and POC contents were 0.1-7.9 times more than that of TOC content. There were significant positive relationships between TOC and LOC, LFOC and POC, suggesting that the active organic carbon components could reflect the change of soil total carbon content.

Late quaternary environmental changes in the upper Las Vegas valley, Nevada

Science.gov (United States)

Quade, Jay

1986-11-01

Five stratigraphic units and five soils of late Pleistocene to Holocene age crop out in dissected badlands on Corn Creek Flat, 30 km northwest of Las Vegas, Nevada, and at Tule Springs, nearer to Las Vegas. The record is dominantly fluvial but contains evidence of several moister, marsh-forming periods: the oldest (Unit B) dates perhaps to the middle Wisconsin, and the more widespread Unit D falls between 30,000 and 15,000 yr B.P. Unit D therefore correlates with pluvial maximum lacustrine deposits elsewhere in the Great Basin. Standing water was not of sufficient depth or extent during either period to form lake strandlines. Between 14,000 and 7200 yr B.P. (Unit E), standing surface water gradually decreased, a trend also apparent in Great Basin pluvial lake chronologies during the same period. Groundwater carbonate cementation and burrowing by cicadas (Cicadae) accompany the moist-phase units. After 7200 yr B.P., increased wind action, decreased biotic activity, and at least 25 m of water-table lowering accompanied widespread erosion of older fine-grained deposits. Based on pack-rat midden and pollen evidence, this coincides with major vegetation changes in the valley, from sagebrush-dominated steppe to lower Mohave desertscrub.

Biostratigraphy and carbon isotope stratigraphy of uppermost Cretaceous-lower Cenozoic Muzzle Group in middle Clarence valley, New Zealand

International Nuclear Information System (INIS)

Hollis, C.J.; Field, B.D.; Jones, C.M.; Strong, C.P.; Wilson, G.J.; Dickens, G.R.

2005-01-01

Muzzle Group strata exposed along southeast-flowing tributaries of the Clarence River valley, Marlborough, record hemipelagic-pelagic sedimentation across a high latitude (c. 55 degrees S), terrigenous sediment-starved, continental margin from latest Cretaceous to middle Eocene times. Studies of dinoflagellates, foraminifera, calcareous nannofossils, and radiolarians have been integrated with bulk carbonate δ 13 C profiles to establish the chronostratigraphy for two stratigraphic sections along Bluff and Muzzle Streams, middle Clarence valley. The two sections comprise similar successions. Uppermost Cretaceous (upper Haumurian) micritic limestone of Mead Hill Formation is overlain unconformably by Teredo Limestone, a c. 0.25 m thick bed of highly glauconitic, calcareous sandstone. This unit, the basal member of Amuri Limestone, is overlain conformably by c. 15 m thick Lower Limestone, micritic limestone that is glauconitic at base and progressively more marl-rich in its upper part. Lower Limestone grades up into Lower Marl, a poorly exposed, 40-70 m thick unit of alternating marl and micritic limestone beds. Biostratigraphy indicates that the base of Amuri Limestone is younger at Bluff Stream (earliest Eocene, early Waipawan) than at Muzzle Stream (late Paleocene, late Teurian). In the condensed (12 m) upper Paleocene-lower Eocene Amuri Limestone sequence at Muzzle Stream, a trend in δ 13 C from high (≥2.4 permille) to low (≤1 permille) values is consistent with global records across three major climate or carbon cycle perturbations: the late Paleocene carbon isotope maximum (PCIM, 59-56 Ma), the initial Eocene thermal maximum (IETM, 55.5 Ma), and the early Eocene climatic optimum (EECO, 53-50 Ma). Probably only the upper PCIM is preserved in the 4 m thick siliceous limestone interval overlying Teredo Limestone. The IETM is well-defined by a 1 permille negative δ 13 C excursion at the base of a 0.8 m thick marl-rich unit (Dee Marl), 5 m above the base of

Structural evolution of the east Sierra Valley system (Owens Valley and vicinity), California: a geologic and geophysical synthesis

Science.gov (United States)

Stevens, Calvin H.; Stone, Paul; Blakely, Richard J.

2013-01-01

The tectonically active East Sierra Valley System (ESVS), which comprises the westernmost part of the Walker Lane-Eastern California Shear Zone, marks the boundary between the highly extended Basin and Range Province and the largely coherent Sierra Nevada-Great Valley microplate (SN-GVm), which is moving relatively NW. The recent history of the ESVS is characterized by oblique extension partitioned between NNW-striking normal and strike-slip faults oriented at an angle to the more northwesterly relative motion of the SN-GVm. Spatially variable extension and right-lateral shear have resulted in a longitudinally segmented valley system composed of diverse geomorphic and structural elements, including a discontinuous series of deep basins detected through analysis of isostatic gravity anomalies. Extension in the ESVS probably began in the middle Miocene in response to initial westward movement of the SN-GVm relative to the Colorado Plateau. At ca. 3-3.5 Ma, the SN-GVm became structurally separated from blocks directly to the east, resulting in significant basin-forming deformation in the ESVS. We propose a structural model that links high-angle normal faulting in the ESVS with coeval low-angle detachment faulting in adjacent areas to the east.

Geology along Mosca Pass Trail, Great Sand Dunes National Park and Preserve, Colorado

Science.gov (United States)

Lindsey, David A.; Klein, Terry L.; Valdez, Andrew; Webster, Robert J.

2012-01-01

Mosca Pass Trail takes the hiker on a journey into the Earth's crust. Here you can see the results of tremendous tectonic forces that bend and tear rocks apart and raise mountain ranges. The trail begins near the Sangre de Cristo fault, which separates the Sangre de Cristo Range from the San Luis Valley. The valley is part of the Rio Grande rift, a series of fault basins extending from southern New Mexico to central Colorado, wherein the Earth's crust has been pulled apart during the last 30 million years. Thousands of feet of sediment, brought by streams mostly from the Sangre de Cristo Range, fill the San Luis Valley beneath the Great Sand Dunes. The trail ends at Mosca Pass overlooking Huerfano Park. The park is part of the larger Raton Basin, formed by compression of the Earth's crust during the Laramide orogeny, which occurred 70–40 million years ago. Massive highlands, the remnants of which are preserved in the Sangre de Cristo Range, were uplifted and pushed over the western side of the Raton Basin. Streams eroded the highland as it rose and filled the Raton Basin with sediment. After the sediment was compacted and cemented to form sedimentary rock, the Huerfano River and other streams began to excavate the basin. Over an unknown but long timespan that probably lasted millions of years, relatively soft sedimentary rocks were removed by the river to form the valley we call "Huerfano Park." Between the ends of the trail, the hiker walks through an erosional "window," or opening, into red sedimentary rocks overridden by gneiss, a metamorphic rock, during the Laramide orogeny. This window gives the hiker a glimpse into the Laramide highland of 70–40 million years ago that preceded the present-day Sangre de Cristo Range. The window is the focus of this trail guide. At the east end of the trail, near Mosca Pass, another trail follows the ridgeline south to Carbonate Mountain. Immediately after reaching the first summit above tree line, this trail crosses a

The Characteristic of Molten Heat Salt Storage System Utilizing Solar Energy Combined with Valley Electric

Directory of Open Access Journals (Sweden)

LI .Jiu-ru

2017-02-01

Full Text Available With the environmental pollution and energy consumption clue to the large difference between peak and valley of power grid，the molten salt heat storage system(MSHSS utilizing solar Energy combined with valley electric is presented for good energy saving and low emissions. The costs of MSHSS utilizing solar Energy combined with valley electric are greatly reduced. The law of heat transfer in molten salt heat storage technology is studied with the method of grey correlation analysis. The results show the effect of elbow sizes on surface convective heat transfer coefficient with different flow velocities.

Tectonic setting of the Great Dyke, Chembadzi, Chewore and Atchiza layered complexes in Zimbabwe and Mozambique

International Nuclear Information System (INIS)

Master, S.

1990-01-01

The Great Dyke of Zimbabwe is one of the largest ultramafic-mafic layered igneous complexexs in the world. Because of the economic importance of large layered intrusions like the Great Dyke, their tectonic setting is of great interest. The Chembadzi complex is a 14 km long, dyke-like layered intrusion up to 800m wide. The Chewore complex, which was thought to have the structure of an irregular lopolith, outcrops over an area of about 200 km in horst blocks in the lower Zambezi Valley in northern Zimbabwe. The Atchiza complex is situated just north of the Cahora Bassa lake and the Zambezi River valley in Mozambique. In considering the tectonic setting of the Great Dyke and its correlatives, most attention has been focussed on events in the Limpopo Mobile Belt, which were responsible for producing the fractures in the Zimbabwe craton that is occupied by the intrusives. 39 refs

Winter flooding in Dutch stream valley floodplains: biogeochemical effects and vegetation consequences

NARCIS (Netherlands)

Beumer, V.

2009-01-01

Winter flooding in Dutch stream valley floodplains: biogeochemical effects and vegetation consequences Victor Beumer Climatic change has great impacts on stream catchments and their ecology. Expectations are that more extreme climate events will result in undesired flooding in stream catchments. In

Charcterization of meadow ecosystems based on watershed and valley segment/reach scale characteristics [chapter 7

Science.gov (United States)

Wendy Trowbridge; Jeanne C. Chambers; Dru Germanoski; Mark L. Lord; Jerry R. Miller; David G. Jewett

2011-01-01

Great Basin riparian meadows are highly sensitive to both natural and anthropogenic disturbance. As detailed in earlier chapters, streams in the central Great Basin have a natural tendency to incise due to their geomorphic history (Miller and others 2001, 2004). Anthropogenic disturbances, including overgrazing by livestock, mining activities, and roads in the valley...

Structural Evolution of the East Sierra Valley System (Owens Valley and Vicinity, California: A Geologic and Geophysical Synthesis

Directory of Open Access Journals (Sweden)

Richard J. Blakely

2013-04-01

Full Text Available The tectonically active East Sierra Valley System (ESVS, which comprises the westernmost part of the Walker Lane-Eastern California Shear Zone, marks the boundary between the highly extended Basin and Range Province and the largely coherent Sierra Nevada-Great Valley microplate (SN-GVm, which is moving relatively NW. The recent history of the ESVS is characterized by oblique extension partitioned between NNW-striking normal and strike-slip faults oriented at an angle to the more northwesterly relative motion of the SN-GVm. Spatially variable extension and right-lateral shear have resulted in a longitudinally segmented valley system composed of diverse geomorphic and structural elements, including a discontinuous series of deep basins detected through analysis of isostatic gravity anomalies. Extension in the ESVS probably began in the middle Miocene in response to initial westward movement of the SN-GVm relative to the Colorado Plateau. At ca. 3–3.5 Ma, the SN-GVm became structurally separated from blocks directly to the east, resulting in significant basin-forming deformation in the ESVS. We propose a structural model that links high-angle normal faulting in the ESVS with coeval low-angle detachment faulting in adjacent areas to the east.

Seasonal and diurnal variations in methane and carbon dioxide in the Kathmandu Valley in the foothills of the central Himalayas

Directory of Open Access Journals (Sweden)

K. S. Mahata

2017-10-01

Full Text Available The SusKat-ABC (Sustainable Atmosphere for the Kathmandu Valley–Atmospheric Brown Clouds international air pollution measurement campaign was carried out from December 2012 to June 2013 in the Kathmandu Valley and surrounding regions in Nepal. The Kathmandu Valley is a bowl-shaped basin with a severe air pollution problem. This paper reports measurements of two major greenhouse gases (GHGs, methane (CH4 and carbon dioxide (CO2, along with the pollutant CO, that began during the campaign and were extended for 1 year at the SusKat-ABC supersite in Bode, a semi-urban location in the Kathmandu Valley. Simultaneous measurements were also made during 2015 in Bode and a nearby rural site (Chanban  ∼  25 km (aerial distance to the southwest of Bode on the other side of a tall ridge. The ambient mixing ratios of methane (CH4, carbon dioxide (CO2, water vapor, and carbon monoxide (CO were measured with a cavity ring-down spectrometer (G2401; Picarro, USA along with meteorological parameters for 1 year (March 2013–March 2014. These measurements are the first of their kind in the central Himalayan foothills. At Bode, the annual average mixing ratios of CO2 and CH4 were 419.3 (±6.0 ppm and 2.192 (±0.066 ppm, respectively. These values are higher than the levels observed at background sites such as Mauna Loa, USA (CO2: 396.8 ± 2.0 ppm, CH4: 1.831 ± 0.110 ppm and Waliguan, China (CO2: 397.7 ± 3.6 ppm, CH4: 1.879 ± 0.009 ppm during the same period and at other urban and semi-urban sites in the region, such as Ahmedabad and Shadnagar (India. They varied slightly across the seasons at Bode, with seasonal average CH4 mixing ratios of 2.157 (±0.230 ppm in the pre-monsoon season, 2.199 (±0.241 ppm in the monsoon, 2.210 (±0.200 ppm in the post-monsoon, and 2.214 (±0.209 ppm in the winter season. The average CO2 mixing ratios were 426.2 (±25.5 ppm in the pre-monsoon, 413.5 (±24.2 ppm in the monsoon

The seasonal cycle of the mixing layer height and its impact on black carbon concentrations in the Kathmandu Valley (Nepal)

Science.gov (United States)

Mues, Andrea; Rupakheti, Maheswar; Hoor, Peter; Bozem, Heiko; Münkel, Christoph; Lauer, Axel; Butler, Tim

2016-04-01

The properties and the vertical structure of the mixing layer as part of the planetary boundary layer are of key importance for local air quality. They have a substantial impact on the vertical dispersion of pollutants in the lower atmosphere and thus on their concentrations near the surface. In this study, ceilometer measurements taken within the framework of the SusKat project (Sustainable Atmosphere for the Kathmandu Valley) are used to investigate the mixing layer height in the Kathmandu Valley, Nepal. The applied method is based on the assumption that the aerosol concentration is nearly constant in the vertical and distinctly higher within the mixing layer than in the air above. Thus, the height with the steepest gradient within the ceilometer backscatter profile marks the top of the mixing layer. Ceilometer and black carbon (BC) measurements conducted from March 2013 through February 2014 provide a unique and important dataset for the analysis of the meteorological and air quality conditions in the Kathmandu Valley. In this study the mean diurnal cycle of the mixing layer height in the Kathmandu Valley for each season (pre-monsoon, monsoon, post-monsoon and winter season) and its dependency on the meteorological situation is investigated. In addition, the impact of the mixing layer height on the BC concentration is analyzed and compared to the relevance of other important processes such as emissions, horizontal advection and deposition. In all seasons the diurnal cycle is typically characterized by low mixing heights during the night, gradually increasing after sun rise reaching to maximum values in the afternoon before decreasing again. Seasonal differences can be seen particularly in the height of the mixing layer, e.g. from on average 153/1200 m (pre-monsoon) to 241/755 m (monsoon season) during the night/day, and the duration of enhanced mixing layer heights during daytime (around 12 hours (pre-monsoon season) to 8 hours (winter)). During the monsoon

PM10 source apportionment study in Pleasant Valley, Nevada

International Nuclear Information System (INIS)

Egami, R.T.; Chow, J.C.; Watson, J.G.; DeLong, T.

1990-01-01

A source apportionment study was conducted between March 18 and April 4, 1988, at Pleasant Valley, Nevada, to evaluate air pollutant concentrations to which community residents were exposed and the source contributions to those pollutants. Daily PM 10 samples were taken for chemical speciation of 40 trace elements, ions, and organic and elemental carbon. This paper reports that the objectives of this case study are: to determine the emissions source composition of the potential upwind source, a geothermal plant; to measure the ambient particulate concentration and its chemical characteristics in Pleasant Valley; and to estimate the contributions of different emissions sources to PM 10 . The study found that: particulate emissions from the geothermal cooling-tower plume consisted primarily of sulfate, ammonia, chloride, and trace elements; no significant quantities of toxic inorganic species were found in the ambient air; ambient PM 10 concentrations in Pleasant Valley were within Federal standards; and source contribution to PM 10 were approximately 60% geological material; 20% motor vehicle exhaust; and 10% cooling-tower plume

Geology, selected geophysics, and hydrogeology of the White River and parts of the Great Salt Lake Desert regional groundwater flow systems, Utah and Nevada

Science.gov (United States)

Rowley, Peter D.; Dixon, Gary L.; Watrus , James M.; Burns, Andrews G.; Mankinen, Edward A.; McKee, Edwin H.; Pari, Keith T.; Ekren, E. Bartlett; Patrick , William G.; Comer, John B.; Inkenbrandt, Paul C.; Krahulec, K.A.; Pinnell, Michael L.

2016-01-01

The east-central Great Basin near the Utah-Nevada border contains two great groundwater flow systems. The first, the White River regional groundwater flow system, consists of a string of hydraulically connected hydrographic basins in Nevada spanning about 270 miles from north to south. The northernmost basin is Long Valley and the southernmost basin is the Black Mountain area, a valley bordering the Colorado River. The general regional groundwater flow direction is north to south. The second flow system, the Great Salt Lake Desert regional groundwater flow system, consists of hydrographic basins that straddle

Black carbon concentrations in the highly polluted Kathmandu Valley, Nepal: a three year monitoring with a dual-spot Aethalometer

Science.gov (United States)

Rupakheti, Maheswar; Drinovec, Luka; Puppala, SivaPraveen; Mahata, Khadak; Rupakheti, Dipesh; Kathayat, Bhogendra; Singdan, Pratik; Panday, Arnico; Lawrence, Mark

2016-04-01

Our knowledge about ambient black carbon (BC) in the vast Himalayan region, a region vulnerable to impacts of global warming, is very limited due to unavailability of a long-term ambient monitoring. Here we present results from a continuous monitoring of ambient BC concentrations, with a new generation Aethalometer (AE33), over a three year period (January 2013- January 2016) at a semi-urban site in the highly polluted Kathmandu Valley in the foothills of the central Himalaya, one of the most polluted cities in the world. This is the longest time series of BC concentrations that have been monitored with AE33 (which uses the dual-spot technique for a real-time filter loading compensation) in highly polluted ambient environment. The measurements were carried out under the framework of project SusKat (Sustainable Atmosphere for the Kathmandu Valley). BC concentrations were found to be extremely high, especially in winter and the pre-monsoon period, with the hourly-averaged values often exceeding 50 μg/m3. BC concentrations showed a clear diurnal cycle with a prominent peak around 8-9 am and a second peak around 8-9 pm local time in all four seasons. Night-time BC was also fairly high. The diurnal cycle was driven by a combination of increased emissions from traffic, cooking activities, garbage burning, and lower mixing heights (˜200 m) and reduced horizontal ventilation in the mornings and evenings. BC concentrations showed significant seasonal variations - a maximum in winter season and minimum during the monsoon (rainy) season, with monthly average values in the range 5-30 μg/m3. An increase in emissions from the operation of over 100 brick kilns in winter and spring, and an increase in the use of small but numerous diesel power generators during hours with power cuts contributed significantly to ambient BC concentrations in the valley. Fractional contributions of biomass burning and fossil fuel combustion to BC was estimated based on a real-time method for

77 FR 33237 - Saline Valley Warm Springs Management Plan/Environmental Impact Statement, Death Valley National...

Science.gov (United States)

2012-06-05

... Valley Warm Springs Management Plan/Environmental Impact Statement, Death Valley National Park, Inyo... an Environmental Impact Statement for the Saline Valley Warm Springs Management Plan, Death Valley... analysis process for the Saline Valley Warm Springs Management Plan for Death Valley [[Page 33238...

Holocene evolution of the Tonle Sap Lake: valley network infill and rates of sedimentation in Cambodia's Great Lake

Science.gov (United States)

Best, J.; Darby, S. E.; Langdon, P. G.; Hackney, C. R.; Leyland, J.; Parsons, D. R.; Aalto, R. E.; Marti, M.

2017-12-01

Tonle Sap Lake, the largest freshwater lake in SE Asia (c. 120km long and 35 km wide), is a vital ecosystem that provides 40-60% of the protein for the population of Cambodia. The lake is fed by flow from the Mekong River that causes the lake rise in level by c. 8m during monsoonal and cyclone-related floods, with drainage of the lake following the monsoon. Hydropower dam construction on the Mekong River has raised concerns as to the fragility of the Tonle Sap habitat due to any changing water levels and sedimentation rates within the lake. This paper details results of sub-bottom profiling surveys of Tonle Sap Lake in October 2014 that detailed the stratigraphy of the lake and assessed rates of infill. An Innomar Parametric Echo Sounder (PES) was used to obtain c. 250 km of sub-bottom profiles, with penetration up to 15m below the lake bed at a vertical resolution of c. 0.20m. These PES profiles were linked to cores from the north of the lake and previous literature. The PES profiles reveal a network of valleys, likely LGM, with relief up to c. 15-20m, that have been infilled by a suite of Holocene sediments. The valley surface is picked out as a strong reflector throughout the lake, and displays a series of valleys that are up to c. 15m deep and commonly 50-200m wide, although some of the largest valleys are 1.2km in width. Modelling of channel network incision during LGM conditions generates landscapes consistent with our field observations. The Tonle Sap valley network is infilled by sediments that show firstly fluvial and/or subaerial slope sedimentation, and then by extensive, parallel-bedded, lacustrine sedimentation. Lastly, the top c. 1m of sedimentation is marked by a distinct basal erosional surface that can be traced over much of the Tonle Sap Lake, and that is overlain by a series of parallel PES reflections. This upper sediment layer is interpreted to represent sedimentation in the Tonle Sap lake due to sediment suspension settling but after a period

Energy and environmental implications of carbon emission reduction targets: Case of Kathmandu Valley, Nepal

International Nuclear Information System (INIS)

Shrestha, Ram M.; Rajbhandari, Salony

2010-01-01

This paper analyzes the sectoral energy consumption pattern and emissions of CO 2 and local air pollutants in the Kathmandu Valley, Nepal. It also discusses the evolution of energy service demands, structure of energy supply system and emissions from various sectors under the base case scenario during 2005-2050. A long term energy system planning model of the Kathmandu Valley based on the MARKet ALlocation (MARKAL) framework is used for the analyses. Furthermore, the paper analyzes the least cost options to achieve CO 2 emission reduction targets of 10%, 20% and 30% below the cumulative emission level in the base case and also discusses their implications for total cost, technology-mix, energy-mix and local pollutant emissions. The paper shows that a major switch in energy use pattern from oil and gas to electricity would be needed in the Valley to achieve the cumulative CO 2 emission reduction target of 30% (ER30). Further, the share of electricity in the cumulative energy consumption of the transport sector would increase from 12% in the base case to 24% in the ER30 case.

Mechanisms of carbon storage in mountainous headwater rivers

Science.gov (United States)

Ellen Wohl; Kathleen Dwire; Nicholas Sutfin; Lina Polvi; Roberto Bazan

2012-01-01

Published research emphasizes rapid downstream export of terrestrial carbon from mountainous headwater rivers, but little work focuses on mechanisms that create carbon storage along these rivers, or on the volume of carbon storage. Here we estimate organic carbon stored in diverse valley types of headwater rivers in Rocky Mountain National Park, CO, USA. We show that...

Hydrology and surface morphology of the Bonneville Salt Flats and Pilot Valley Playa, Utah

Science.gov (United States)

Lines, Gregory C.

1979-01-01

The Bonneville Salt Flats and Pilot Valley are in the western part of the Great Salt Lake Desert in northwest Utah. The areas are separate, though similar, hydrologic basins, and both contain a salt crust. The Bonneville salt crust covered about 40 square miles in the fall of 1976, and the salt crust in Pilot Valley covered 7 square miles. Both areas lack any noticeable surface relief (in 1976, 1.3 feet on the Bonneville salt crust and 0.3 foot on the Pilot Valley salt crust).The salt crust on the Salt Flats has been used for many years for automobile racing, and brines from shallow lacustrine deposits have been used for the production of potash. In recent years, there has been an apparent conflict between these two major uses of the area as the salt crust has diminished in both thickness and extent. Much of the Bonneville Racetrack has become rougher, and there has also been an increase in the amount of sediment on the south end of the racetrack. The Pilot Valley salt crust and surrounding playa have been largely unused.Evaporite minerals on the Salt Flats and the Pilot Valley playa are concentrated in three zones: (1) a carbonate zone composed mainly of authigenic clay-size carbonate minerals, (2) a sulfate zone composed mainly of authigenic gypsum, and (3) a chloride zone composed of crystalline halite (the salt crust). Five major types of salt crust were recognized on the Salt Flats, but only one type was observed in Pilot Valley. Geomorphic differences in the salt crust are caused by differences in their hydrologic environments. The salt crusts are dynamic features that are subject to change because of climatic factors and man's activities.Ground water occurs in three distinct aquifers in much of the western Great Salt Lake Desert: (1) the basin-fill aquifer, which yields water from conglomerate in the lower part of the basin fill, (2) the alluvial-fan aquifer, which yields water from sand and gravel along the western margins of both playas, and (3) the

Late Pleistocene Hansel Valley basaltic ash, northern Lake Bonneville, Utah, USA

Science.gov (United States)

Miller, D.M.; Oviatt, Charles G.; Nash, B.P.

2008-01-01

The Hansel Valley ash bed lies within 5 cm of the base of deposits of Lake Bonneville (???28 ka) in the vicinity of Great Salt Lake and provides a useful stratigraphic marker for this area of the lake basin. However, it has not been matched to an eruptive edifice, presumably because such an edifice was eroded by waves of Lake Bonneville. We present data for the chemical composition of the tephra and for possible matching lavas and tephras of the region, as well as grain size data for the tephra in an attempt to identify the location of the eruption. Matches with other tephras are negative, but lavas near the coarsest ash deposits match well with the distinctive high values of TiO2 and P2O5 of the ash. Neither chemistry nor grain size data points uniquely to a source area, but an area near the northwest shore of Great Salt Lake and within Curlew Valley is most likely. The Hansel Valley ash is an example of an ash that has no direct numerical date from proximal deposits, despite considerable study, yet nonetheless is useful for stratigraphic studies by virtue of its known stratigraphic position and approximate age. Basaltic tephras commonly are not as widespread as their rhyolitic counterparts, and in some cases apparently are produced by eruptive sources that are short lived and whose edifices are not persistent. ?? 2007 Elsevier Ltd and INQUA.

Valley polarization in bismuth

Science.gov (United States)

Fauque, Benoit

2013-03-01

The electronic structure of certain crystal lattices can contain multiple degenerate valleys for their charge carriers to occupy. The principal challenge in the development of valleytronics is to lift the valley degeneracy of charge carriers in a controlled way. In bulk semi-metallic bismuth, the Fermi surface includes three cigar-shaped electron valleys lying almost perpendicular to the high symmetry axis known as the trigonal axis. The in-plane mass anisotropy of each valley exceeds 200 as a consequence of Dirac dispersion, which drastically reduces the effective mass along two out of the three orientations. According to our recent study of angle-dependent magnetoresistance in bismuth, a flow of Dirac electrons along the trigonal axis is extremely sensitive to the orientation of in-plane magnetic field. Thus, a rotatable magnetic field can be used as a valley valve to tune the contribution of each valley to the total conductivity. As a consequence of a unique combination of high mobility and extreme mass anisotropy in bismuth, the effect is visible even at room temperature in a magnetic field of 1 T. Thus, a modest magnetic field can be used as a valley valve in bismuth. The results of our recent investigation of angle-dependent magnetoresistance in other semi-metals and doped semiconductors suggest that a rotating magnetic field can behave as a valley valve in a multi-valley system with sizeable mass anisotropy.

Transport of regional pollutants through a remote trans-Himalayan valley in Nepal

Directory of Open Access Journals (Sweden)

S. Dhungel

2018-01-01

Full Text Available Anthropogenic emissions from the combustion of fossil fuels and biomass in Asia have increased in recent years. High concentrations of reactive trace gases and light-absorbing and light-scattering particles from these sources form persistent haze layers, also known as atmospheric brown clouds, over the Indo–Gangetic plains (IGP from December through early June. Models and satellite imagery suggest that strong wind systems within deep Himalayan valleys are major pathways by which pollutants from the IGP are transported to the higher Himalaya. However, observational evidence of the transport of polluted air masses through Himalayan valleys has been lacking to date. To evaluate this pathway, we measured black carbon (BC, ozone (O3, and associated meteorological conditions within the Kali Gandaki Valley (KGV, Nepal, from January 2013 to July 2015. BC and O3 varied over both diurnal and seasonal cycles. Relative to nighttime, mean BC and O3 concentrations within the valley were higher during daytime when the up-valley flow (average velocity of 17 m s−1 dominated. BC and O3 concentrations also varied seasonally with minima during the monsoon season (July to September. Concentrations of both species subsequently increased post-monsoon and peaked during March to May. Average concentrations for O3 during the seasonally representative months of April, August, and November were 41.7, 24.5, and 29.4 ppbv, respectively, while the corresponding BC concentrations were 1.17, 0.24, and 1.01 µg m−3, respectively. Up-valley fluxes of BC were significantly greater than down-valley fluxes during all seasons. In addition, frequent episodes of BC concentrations 2–3 times higher than average persisted from several days to a week during non-monsoon months. Our observations of increases in BC concentration and fluxes in the valley, particularly during pre-monsoon, provide evidence that trans-Himalayan valleys are important conduits for transport of

Transport of regional pollutants through a remote trans-Himalayan valley in Nepal

Science.gov (United States)

Dhungel, Shradda; Kathayat, Bhogendra; Mahata, Khadak; Panday, Arnico

2018-01-01

Anthropogenic emissions from the combustion of fossil fuels and biomass in Asia have increased in recent years. High concentrations of reactive trace gases and light-absorbing and light-scattering particles from these sources form persistent haze layers, also known as atmospheric brown clouds, over the Indo-Gangetic plains (IGP) from December through early June. Models and satellite imagery suggest that strong wind systems within deep Himalayan valleys are major pathways by which pollutants from the IGP are transported to the higher Himalaya. However, observational evidence of the transport of polluted air masses through Himalayan valleys has been lacking to date. To evaluate this pathway, we measured black carbon (BC), ozone (O3), and associated meteorological conditions within the Kali Gandaki Valley (KGV), Nepal, from January 2013 to July 2015. BC and O3 varied over both diurnal and seasonal cycles. Relative to nighttime, mean BC and O3 concentrations within the valley were higher during daytime when the up-valley flow (average velocity of 17 m s-1) dominated. BC and O3 concentrations also varied seasonally with minima during the monsoon season (July to September). Concentrations of both species subsequently increased post-monsoon and peaked during March to May. Average concentrations for O3 during the seasonally representative months of April, August, and November were 41.7, 24.5, and 29.4 ppbv, respectively, while the corresponding BC concentrations were 1.17, 0.24, and 1.01 µg m-3, respectively. Up-valley fluxes of BC were significantly greater than down-valley fluxes during all seasons. In addition, frequent episodes of BC concentrations 2-3 times higher than average persisted from several days to a week during non-monsoon months. Our observations of increases in BC concentration and fluxes in the valley, particularly during pre-monsoon, provide evidence that trans-Himalayan valleys are important conduits for transport of pollutants from the IGP to the

Carbon cycle dynamics within Oregon’s urban-suburban-forested-agricultural landscapes

Energy Technology Data Exchange (ETDEWEB)

Law, Beverly E. [Oregon State Univ., Corvallis, OR (United States); Still, Christopher Jason [Oregon State Univ., Corvallis, OR (United States); Schmidt, Andres [Oregon State Univ., Corvallis, OR (United States)

2017-06-15

Our overarching goal was to develop and utilize an observation-based analysis framework to assess interactions between climate and mosaics of land use, land cover and urbanization on regional carbon, water, and energy dynamics, and potential changes associated with land management and climate. Carbon, water and energy cycling was quantified for the range of current and potential land uses under present and future climates. The study region of Oregon has a strong climatic gradient from the coastal mesic forests (2500mm ppt) to the Willamette Valley, Cascade Mountains, and the Northern Great Basin semi-arid “cold desert” to the east (300 mm). The study was focused on the effects of (1) conversion of semi-arid sagebrush and Willamette Valley agricultural crops to bioenergy production; (2) afforestation of idle land and rangelands deemed suitable for forests or poplar crops under future climate conditions. We found that net ecosystem production (NEP), the net of ecosystem photosynthesis and respiration, was 10 times higher in the high biomass forests of the Coast Range compared with drier regions like sagebrush in the Northern Great Basin, which was nearly zero (Schmidt et al. 2016). The state total NEP averaged about 30 teragrams carbon (Tg C) per year for the years 2012 to 2014 using our model framework that we developed for predictions of current and future NEP, and compared well with our detailed inventory estimates (28 Tg C annual average for 2011-2015 for forests only; Law et al. 2017). Running our model framework until the year 2050, we found that climate alone only increased NEP by less than 1 Tg C per decade (~3%) using the current trajectory of carbon dioxide emissions, however, changes are expected to be more rapid in subsequent years. We evaluated the possibility of land use change from grass seed crops to poplar for bioenergy, which slightly increased NEP by 2050. The most important variable for carbon sequestration estimates (net carbon sources and

Greening Turner Valley

International Nuclear Information System (INIS)

Byfield, M.

2010-01-01

This article discussed remedial activities undertaken in the Turner Valley. Remedial action in the valley must satisfy the financial concerns of engineers and investors as well as the environmental concerns of residents and regulators. Natural gas production in the Turner Valley began in 1914. The production practices were harmful and wasteful. Soil and water pollution was not considered a problem until recently. The impacts of cumulative effects and other pollution hazards are now being considered as part of many oil and gas environmental management programs. Companies know it is cheaper and safer to prevent pollutants from being released, and more efficient to clean them up quickly. Oil and gas companies are also committed to remediating historical problems. Several factors have simplified remediation plans in the Turner Valley. Area real estate values are now among the highest in Alberta. While the valley residents are generally friendly to the petroleum industry, strong communication with all stakeholders in the region is needed. 1 fig.

Baseline and projected future carbon storage and greenhouse-gas fluxes in the Great Plains region of the United States

Science.gov (United States)

Bouchard, Michelle; Butman, David; Hawbaker, Todd; Li, Zhengpeng; Liu, Jinxun; Liu, Shu-Guang; McDonald, Cory; Reker, Ryan R.; Sayler, Kristi; Sleeter, Benjamin; Sohl, Terry; Stackpoole, Sarah; Wein, Anne; Zhu, Zhi-Liang; Zhu, Zhi-Liang

2011-01-01

This assessment was conducted to fulfill the requirements of section 712 of the Energy Independence and Security Act (EISA) of 2007 and to improve understanding of carbon and greenhouse gas (GHG) fluxes in the Great Plains region in the central part of the United States. The assessment examined carbon storage, carbon fluxes, and other GHG fluxes (methane and nitrous oxide) in all major terrestrial ecosystems (forests, grasslands/shrublands, agricultural lands, and wetlands) and freshwater aquatic systems (rivers, streams, lakes, and impoundments) in two time periods: baseline (generally in the first half of the 2010s) and future (projections from baseline to 2050). The assessment was based on measured and observed data collected by the U.S. Geological Survey (USGS) and many other agencies and organizations and used remote sensing, statistical methods, and simulation models.

Geologic characterization report for the Paradox Basin Study Region, Utah Study Areas. Volume 6: Salt Valley

Science.gov (United States)

1984-12-01

Surface landforms in the Salt Valley Area are generally a function of the Salt Valley anticline and are characterized by parallel and subparallel cuestaform ridges and hogbacks and flat valley floors. The most prominent structure in the Area is the Salt Valley anticline. Erosion resulting from the Tertiary uplift of the Colorado Plateau led to salt dissolution and subsequent collapse along the crest of the anticline. Continued erosion removed the collapse material, forming an axial valley along the crest of the anticline. Paleozoic rocks beneath the salt bearing Paradox Formation consist of limestone, dolomite, sandstone, siltstone and shale. The salt beds of the Paradox formation occur in distinct cycles separated by an interbed sequence of anhydrite, carbonate, and clastic rocks. The Paradox Formation is overlain by Pennsylvanian limestone; Permian sandstone; and Mesozoic sandstone, mudstone, conglomerate and shale. No earthquakes have been reported in the area during the period of the historic record and contemporary seismicity appears to be diffusely distributed, of low level and small magnitude. The upper unit includes the Permian strata and upper Honaker trail formation.

Catastrophic valley fills record large Himalayan earthquakes, Pokhara, Nepal

Science.gov (United States)

Stolle, Amelie; Bernhardt, Anne; Schwanghart, Wolfgang; Hoelzmann, Philipp; Adhikari, Basanta R.; Fort, Monique; Korup, Oliver

2017-12-01

Uncertain timing and magnitudes of past mega-earthquakes continue to confound seismic risk appraisals in the Himalayas. Telltale traces of surface ruptures are rare, while fault trenches document several events at best, so that additional proxies of strong ground motion are needed to complement the paleoseismological record. We study Nepal's Pokhara basin, which has the largest and most extensively dated archive of earthquake-triggered valley fills in the Himalayas. These sediments form a 148-km2 fan that issues from the steep Seti Khola gorge in the Annapurna Massif, invading and plugging 15 tributary valleys with tens of meters of debris, and impounding several lakes. Nearly a dozen new radiocarbon ages corroborate at least three episodes of catastrophic sedimentation on the fan between ∼700 and ∼1700 AD, coinciding with great earthquakes in ∼1100, 1255, and 1344 AD, and emplacing roughly >5 km3 of debris that forms the Pokhara Formation. We offer a first systematic sedimentological study of this formation, revealing four lithofacies characterized by thick sequences of mid-fan fluvial conglomerates, debris-flow beds, and fan-marginal slackwater deposits. New geochemical provenance analyses reveal that these upstream dipping deposits of Higher Himalayan origin contain lenses of locally derived river clasts that mark time gaps between at least three major sediment pulses that buried different parts of the fan. The spatial pattern of 14C dates across the fan and the provenance data are key to distinguishing these individual sediment pulses, as these are not evident from their sedimentology alone. Our study demonstrates how geomorphic and sedimentary evidence of catastrophic valley infill can help to independently verify and augment paleoseismological fault-trench records of great Himalayan earthquakes, while offering unparalleled insights into their long-term geomorphic impacts on major drainage basins.

[Influence of fire disturbance on aboveground deadwood debris carbon storage in Huzhong forest region of Great Xing'an Mountains, Northeast China].

Science.gov (United States)

Yang, Da; He, Hong-shi; Wu, Zhi-wei; Liang, Yu; Huang, Chao; Luo, Xu; Xiao, Jiang-tao; Zhang, Qing-long

2015-02-01

Based on the field inventory data, the aboveground deadwood debris carbon storage under different fire severities was analyzed in Huzhong forest region of Great Xing' an Mountains. The results showed that the fire severity had a significant effect on aboveground deadwood debris carbon storage. The deadwood debris carbon storage was in the order of high-severity > low-severity > unburned in Larix gmelinii stands, and mixed conifer-broadleaf stands ( L. gmelinii and Betula platyphylla), and in the order of high severity > unburned > low-severity in B. platyphylla stands. Fire disturbance significantly changed the component percentage of the deadwood debris carbon storage. The component percentage of snags increased and litter decreased with the increasing fire severity. Logs and stumps did not change significantly with the increasing fire severity. The spatial variation of deadwood debris carbon storage in forests burned with low-severity fire was higher than that in unburned forests. The spatial variation of deadwood debris carbon storage with high-severity fires was lowest. This spatial variation needed to be accounted when calculating forest deadwood debris carbon storage.

Air quality modeling in the Valley of Mexico: meteorology, emissions and forecasting

Science.gov (United States)

Garcia-Reynoso, A.; Jazcilevich, A. D.; Diaz-Nigenda, E.; Vazquez-Morales, W.; Torres-Jardon, R.; Ruiz-Suarez, G.; Tatarko, J.; Bornstein, R.

2007-12-01

The Valley of Mexico presents important challenges for air quality modeling: complex terrain, a great variety of anthropogenic and natural emissions sources, and high altitude and low latitude increasing the amount of radiation flux. The modeling group at the CCA-UNAM is using and merging state of the art models to study the different aspects that influence the air quality phenomenon in the Valley of Mexico. The air quality model MCCM that uses MM5 as its meteorological input has been a valuable tool to study important features of the complex and intricate atmospheric flows on the valley, such as local confluences and vertical fumigation. Air quality modeling has allowed studying the interaction between the atmospheres of the valleys surrounding the Valley of Mexico, prompting the location of measurement stations during the MILAGRO campaign. These measurements confirmed the modeling results and expanded our knowledge of the transport of pollutants between the Valleys of Cuernavaca, Puebla and Mexico. The urban landscape of Mexico City complicates meteorological modeling. Urban-MM5, a model that explicitly takes into account the influence of buildings, houses, streets, parks and anthropogenic heat, is being implemented. Preliminary results of urban-MM5 on a small area of the city have been obtained. The current emissions inventory uses traffic database that includes hourly vehicular activity in more than 11,000 street segments, includes 23 area emissions categories, more than 1,000 industrial sources and biogenic emissions. To improve mobile sources emissions a system consisting of a traffic model and a car simulator is underway. This system will allow for high time and space resolution and takes into account motor stress due to different driving regimes. An important source of emissions in the Valley of Mexico is erosion dust. The erosion model WEPS has been integrated with MM5 and preliminary results showing dust episodes over Mexico City have been obtained. A

Evaluating the peak-to-valley dose ratio of synchrotron microbeams using PRESAGE fluorescence

International Nuclear Information System (INIS)

Annabell, N.; Yagi, N.; Umetani, K.; Wong, C.; Geso, M.

2012-01-01

The peak-to-valley dose ratio of a microbeam array can be measured by fluorescence of PRESAGE dosimeters. Peak-to-valley dose ratios are calculated using this new technique and also by EBT2 film. Synchrotron-generated microbeam radiotherapy holds great promise for future treatment, but the high dose gradients present conventional dosimetry with a challenge. Measuring the important peak-to-valley dose ratio (PVDR) of a microbeam-collimated synchrotron source requires both a dosimeter and an analysis method capable of exceptional spatial resolution. The PVDR is of great interest since it is the limiting factor for potential application of the microbeam radiation therapy technique clinically for its tissue-sparing properties (i.e. the valley dose should be below the tolerance of normal tissue). In this work a new method of measuring the dose response of PRESAGE dosimeters is introduced using the fluorescence from a 638 nm laser on a confocal laser-scanning microscope. This fluorescent microscopy method produces dosimetry data at a pixel size as low as 78 nm, giving a much better spatial resolution than optical computed tomography, which is normally used for scanning PRESAGE dosimeters. Using this technique the PVDR of the BL28B2 microbeam at the SPring-8 synchrotron in Japan is estimated to be approximately 52:1 at a depth of 2.5 mm. The PVDR was also estimated with EBT2 GAFchromic films as 30.5:1 at the surface in order to compare the PRESAGE fluorescent results with a more established dosimetry system. This estimation is in good agreement with previously measured ratios using other dosimeters and Monte Carlo simulations. This means that it is possible to use PRESAGE dosimeters with confocal microscopy for the determination of PVDR

Valley-filtered edge states and quantum valley Hall effect in gated bilayer graphene.

Science.gov (United States)

Zhang, Xu-Long; Xu, Lei; Zhang, Jun

2017-05-10

Electron edge states in gated bilayer graphene in the quantum valley Hall (QVH) effect regime can carry both charge and valley currents. We show that an interlayer potential splits the zero-energy level and opens a bulk gap, yielding counter-propagating edge modes with different valleys. A rich variety of valley current states can be obtained by tuning the applied boundary potential and lead to the QVH effect, as well as to the unbalanced QVH effect. A method to individually manipulate the edge states by the boundary potentials is proposed.

2000 emission inventory for the Lower Fraser Valley airshed

International Nuclear Information System (INIS)

2002-10-01

This emissions inventory is a compilation of all emissions in the Lower Fraser Valley International Airshed. Its objective is to harmonize the inventory data of Canada's Greater Vancouver Regional District (GVRD), the Fraser Valley Regional District (FVRD) and Whatcom County in the United States. It provides an idea of the current state of air emissions on both sides of the Canada-United States border. This inventory provides information regarding the types of emissions sources in the region, their location and the amount of air pollution emitted within a given time frame. It is designed to help manage air quality by identifying sectors which need to be more vigilant. The common air pollutants addressed in the inventory include total particulate matter, nitrogen oxides, sulphur oxides, volatile organic compounds, carbon monoxide, and ammonia. The greenhouse gases include carbon dioxide, methane, and nitrous oxide. The inventory distinguishes between point, area, and mobile sources. Carbon monoxide emissions are found to be dominated by cars, trucks and non-road engines. Nitrogen oxide emissions are also dominated by cars, trucks, marine vessels and non-road engines. Natural sources such as trees and vegetation contribute to volatile organic compounds, as do cars, lights trucks and solvent evaporation from industrial, commercial and consumer products. Marine vessels are the largest contributors of sulphur oxide emissions in the region. In addition, the petroleum industry emits 26 per cent of sulphur oxide emissions in the region. Significant amounts of particulate matter come from area sources such as wind erosion in the agricultural sector. Point sources for PM include bulk shipping terminals and the wood products industry. Agriculture contributes the largest amount of ammonia in the region. refs., tabs., figs

Transport of particle pollution into the Maipo Valley: winter 2015 campaign results

Science.gov (United States)

Huneeus, Nicolás; Mazzeo, Andrea; Ordóñez, César; Donoso, Nicolás; Gallardo, Laura; Molina, Luisa; Moreno, Valeria; Muñoz, Ricardo; Orfanoz, Andrea; Vizcarra, Aldo

2016-04-01

Each winter, Santiago (33° 27'S, 70° 40'W) the capital of Chile with a population of about 7 million people, experiences episodes with particulate matter (PM) concentrations larger than allowed by Chilean environmental regulations. Transport and residential heating largely dominate emissions prior to and during these episodes. Important impact of black carbon (BC) on the cryosphere has been documented in other parts of the world associated with urban pollution. In order to explore if BC from Santiago has the potential to reach the Andean cryosphere during the aforementioned episodes, a one week-long campaign was conducted in Santiago and the Maipo Valley between 18th and 25th of July 2015 when the air quality conditions of the city reached twice the critical levels (pre-emergency in Chilean regulations). Measurements were carried out at three sites: downtown Santiago, the entrance of the valley (and outskirts of Santiago) and 12 km inside the Maipo Valley. At each of these sites both surface and vertically distributed measurements were conducted. A meteorological station measuring standard meteorological parameters and an E-Sampler measuring PM10 concentrations were installed at each site. In addition, a tethered balloon equipped with a sonde and a mini-aethalometer was used in each site to measure vertical profiles of standard meteorological parameters and BC concentrations, respectively. The tethered balloon was raised every three hours up to a maximum of 1000 meters above ground level, whenever meteorological conditions allowed. In general, the BC concentrations inside the valley, both at the surface and in the vertical, were dominated by emissions within the valley and BC was limited to shallow layers above the ground. However, on both days with critical air quality levels, winds blowing from the city and deeper BC layers were observed inside the valley. Furthermore, during these days observations at the entrance of the valley and those taken inside were

Karst geomorphology and hydrology of the Shenandoah Valley near Harrisonburg, Virginia

Science.gov (United States)

Doctor, Daniel H.; Orndorff, Wil; Maynard, Joel; Heller, Matthew J.; Casile, Gerolamo C.

2014-01-01

The karst of the central Shenandoah Valley has characteristics of both shallow and deep phreatic formation. This field guide focuses on the region around Harrisonburg, Virginia, where a number of these karst features and their associated geologic context can be examined. Ancient, widespread alluvial deposits cover much of the carbonate bedrock on the western side of the valley, where shallow karstification has resulted in classical fluviokarst development. However, in upland exposures of carbonate rock, isolated caves exist atop hills not affected by surface processes other than exposure during denudation. The upland caves contain phreatic deposits of calcite and fine-grained sediments. They lack any evidence of having been invaded by surface streams. Recent geologic mapping and LIDAR (light detection and ranging) elevation data have enabled interpretive association between bedrock structure, igneous intrusions, silicification and brecciation of host carbonate bedrock, and the location of several caves and karst springs. Geochemistry, water quality, and water temperature data support the broad categorization of springs into those affected primarily by shallow near-surface recharge, and those sourced deeper in the karst aquifer. The deep-seated karst formation occurred in the distant past where subvertical fracture and fault zones intersect thrust faults and/or cross-strike faults, enabling upwelling of deep-circulating meteoric groundwater. Most caves formed in such settings have been overprinted by later circulation of shallow groundwater, thus removing evidence of the history of earliest inception; however, several caves do preserve evidence of an earlier formation.

Carbon Dioxide and Methane Flux Related to Forest Type and Managed and Unmanaged Conditions in the Great Dismal Swamp, USA

Science.gov (United States)

Gutenberg, L. W.; Krauss, K.; Qu, J. J.; Hogan, D. M.; Zhu, Z.; Xu, C.

2017-12-01

The Great Dismal Swamp in Virginia and North Carolina, USA, has been greatly impacted by human use and management for the last few hundred years through logging, ditching, and draining. Today, the once dominant cedar, cypress and pocosin forest types are fragmented due to logging and environmental change. Maple-gum forest has taken over more than half the remaining area of the swamp ecosystem, which is now a National Wildlife Refuge and State Park. The peat soils and biomass store a vast quantity of carbon compared with the size of the refuge, but this store is threatened by fire and drying. This study looks at three of the main forest types in the GDS— maple-sweet gum, tall pine pocosin, and Atlantic white cedar— in terms of their carbon dioxide and methane soil flux. Using static chambers to sample soil gas flux in locally representative sites, we found that cedar sites showed a higher carbon dioxide flux rate as the soil temperature increased than maple sites, and the rate of carbon dioxide flux decreased as soil moisture increased faster in cedar sites than in maple sites. Methane flux increased as temperature increased for pocosin, but decreased with temperature for cedar and maple. All of the methane fluxes increased as soil moisture increased. Cedar average carbon dioxide flux was statistically significantly different from both maple and pocosin. These results show that soil carbon gas flux depends on soil moisture and temperature, which are factors that are changing due to human actions, as well as on forest type, which is also the result of human activity. Some of these variables may be adjustable by the managers of the land. Variables other than forest type, temperature and soil moisture/inundation may also play a role in influencing soil flux, such as stand age, tree height, composition of the peat and nutrient availability, and source of moisture as some sites are more influenced by groundwater from ditches and some more by rainfall depending on the

Microbial ecology of extreme environments: Antarctic dry valley yeasts and growth in substrate limited habitats

Science.gov (United States)

Vishniac, H. S.

1981-01-01

The multiple stresses temperature, moisture, and for chemoheterotrophs, sources of carbon and energy of the Dry Valley Antarctica soils allow at best depauperate communities, low in species diversity and population density. The nature of community structure, the operation of biogeochemical cycles, the evolution and mechanisms of adaptation to this habitat are of interest in informing speculations upon life on other planets as well as in modeling the limits of gene life. Yeasts of the Cryptococcus vishniacil complex (Basidiobiastomycetes) are investigated, as the only known indigenes of the most hostile, lichen free, parts of the Dry Valleys. Methods were developed for isolating these yeasts (methods which do not exclude the recovery of other microbiota). The definition of the complex was refined and the importance of nitrogen sources was established as well as substrate competition in fitness to the Dry Valley habitats.

Infilling and flooding of the Mekong River incised valley during deglacial sea-level rise

Science.gov (United States)

Tjallingii, Rik; Stattegger, Karl; Wetzel, Andreas; Van Phach, Phung

2010-06-01

The abrupt transition from fluvial to marine deposition of incised-valley-fill sediments retrieved from the southeast Vietnamese shelf, accurately records the postglacial transgression after 14 ka before present (BP). Valley-filling sediments consist of fluvial mud, whereas sedimentation after the transgression is characterized by shallow-marine carbonate sands. This change in sediment composition is accurately marked in high-resolution X-ray fluorescence (XRF) core scanning records. Rapid aggradation of fluvial sediments at the river mouth nearly completely filled the Mekong incised valley prior to flooding. However, accumulation rates strongly reduced in the valley after the river-mouth system flooded and stepped back. This also affected the sediment supply to deeper parts of the southeast Vietnamese shelf. Comparison of the Mekong valley-filling with the East Asian sea-level history of sub- and inter-tidal sediment records shows that the transgressive surface preserved in the incised-valley-fill records is a robust sea-level indicator. The valley was nearly completely filled with fluvial sediments between 13.0 and 9.5 ka BP when sea-level rose rather constantly with approximately 10 mm/yr, as indicated by the East Asian sea-level record. At shallower parts of the shelf, significant sediment reworking and the establishment of estuarine conditions at the final stage of infilling complicates accurate dating of the transgressive surface. Nevertheless, incised-valley-fill records and land-based drill sites indicate a vast and rapid flooding of the shelf from the location of the modern Vietnamese coastline to the Cambodian lowlands between 9.5 ka and 8.5 ka BP. Fast flooding of this part of the shelf is related with the low shelf gradient and a strong acceleration of the East Asian sea-level rise from 34 to 9 meter below modern sea level (mbsl) corresponding to the sea-level jump of melt water pulse (MWP) 1C.

Valley development on Hawaiian volcanoes

International Nuclear Information System (INIS)

Baker, V.R.; Gulick, V.C.

1987-01-01

Work in progress on Hawaiian drainage evolution indicates an important potential for understanding drainage development on Mars. Similar to Mars, the Hawaiian valleys were initiated by surface runoff, subsequently enlarged by groundwater sapping, and eventually stabilized as aquifers were depleted. Quantitative geomorphic measurements were used to evaluate the following factors in Hawaiian drainage evolution: climate, stream processes, and time. In comparing regions of similar climate, drainage density shows a general increase with the age of the volcani island. With age and climate held constant, sapping dominated valleys, in contrast to runoff-dominated valleys, display the following: lower drainage densities, higher ratios of valley floor width to valley height, and more positive profile concavities. Studies of stream junction angles indicate increasing junction angles with time on the drier leeward sides of the major islands. The quantitative geomorphic studies and earlier field work yielded important insights for Martian geomorphology. The importance of ash mantling in controlling infiltration on Hawaii also seems to apply to Mars. The Hawaiian valley also have implications for the valley networks of Martian heavily cratered terrains

Quantum transport in carbon nanotubes

NARCIS (Netherlands)

Laird, E.A.; Kuemmeth, F.; Steele, G.A.; Grove-Rasmussen, K.; Nygard, J.; Flensberg, K.; Kouwenhoven, L.P.

2015-01-01

Carbon nanotubes are a versatile material in which many aspects of condensed matter physics come together. Recent discoveries have uncovered new phenomena that completely change our understanding of transport in these devices, especially the role of the spin and valley degrees of freedom. This

Analysis of Mining-induced Valley Closure Movements

Science.gov (United States)

Zhang, C.; Mitra, R.; Oh, J.; Hebblewhite, B.

2016-05-01

Valley closure movements have been observed for decades in Australia and overseas when underground mining occurred beneath or in close proximity to valleys and other forms of irregular topographies. Valley closure is defined as the inward movements of the valley sides towards the valley centreline. Due to the complexity of the local geology and the interplay between several geological, topographical and mining factors, the underlying mechanisms that actually cause this behaviour are not completely understood. A comprehensive programme of numerical modelling investigations has been carried out to further evaluate and quantify the influence of a number of these mining and geological factors and their inter-relationships. The factors investigated in this paper include longwall positional factors, horizontal stress, panel width, depth of cover and geological structures around the valley. It is found that mining in a series passing beneath the valley dramatically increases valley closure, and mining parallel to valley induces much more closure than other mining orientations. The redistribution of horizontal stress and influence of mining activity have also been recognised as important factors promoting valley closure, and the effect of geological structure around the valley is found to be relatively small. This paper provides further insight into both the valley closure mechanisms and how these mechanisms should be considered in valley closure prediction models.

Evaluating connection of aquifers to springs and streams, Great Basin National Park and vicinity, Nevada

Science.gov (United States)

Prudic, David E.; Sweetkind, Donald S.; Jackson, Tracie R.; Dotson, K. Elaine; Plume, Russell W.; Hatch, Christine E.; Halford, Keith J.

2015-12-22

Federal agencies that oversee land management for much of the Snake Range in eastern Nevada, including the management of Great Basin National Park by the National Park Service, need to understand the potential extent of adverse effects to federally managed lands from nearby groundwater development. As a result, this study was developed (1) to attain a better understanding of aquifers controlling groundwater flow on the eastern side of the southern part of the Snake Range and their connection with aquifers in the valleys, (2) to evaluate the relation between surface water and groundwater along the piedmont slopes, (3) to evaluate sources for Big Springs and Rowland Spring, and (4) to assess groundwater flow from southern Spring Valley into northern Hamlin Valley. The study focused on two areas—the first, a northern area along the east side of Great Basin National Park that included Baker, Lehman, and Snake Creeks, and a second southern area that is the potential source area for Big Springs. Data collected specifically for this study included the following: (1) geologic field mapping; (2) drilling, testing, and water quality sampling from 7 test wells; (3) measuring discharge and water chemistry of selected creeks and springs; (4) measuring streambed hydraulic gradients and seepage rates from 18 shallow piezometers installed into the creeks; and (5) monitoring stream temperature along selected reaches to identify places of groundwater inflow.

Light-absorbing Aerosol Properties in the Kathmandu Valley during SusKat-ABC Field Campaign

Science.gov (United States)

Kim, S.; Yoon, S.; Kim, J.; Cho, C.; Jung, J.

2013-12-01

Light-absorbing aerosols, such as black carbon (BC), are major contributors to the atmospheric heating and the reduction of solar radiation reaching at the earth's surface. In this study, we investigate light-absorption and scattering properties of aerosols (i.e., BC mass concentration, aerosol solar-absorption/scattering efficiency) in the Kathmandu valley during Sustainable atmosphere for the Kathmandu valley (SusKat)-ABC campaign, from December 2012 to February 2013. Kathmandu City is among the most polluted cities in the world. However, there are only few past studies that provide basic understanding of air pollution in the Kathmandu Valley, which is not sufficient for designing effective mitigation measures (e.g., technological, financial, regulatory, legal and political measures, planning strategies). A distinct diurnal variation of BC mass concentration with two high peaks observed during wintertime dry monsoon period. BC mass concentration was found to be maximum around 09:00 and 20:00 local standard time (LST). Increased cars and cooking activities including substantial burning of wood and other biomass in the morning and in the evening contributed to high BC concentration. Low BC concentrations during the daytime can be explain by reduced vehicular movement and cooking activities. Also, the developmements of the boundary layer height and mountain-valley winds in the Kathmandu Valley paly a crucial role in the temproal variation of BC mass concentrations. Detailed radiative effects of light-absorbing aerosols will be presented.

Effective porosity and density of carbonate rocks (Maynardville Limestone and Copper Ridge Dolomite) within Bear Creek Valley on the Oak Ridge Reservation based on modern petrophysical techniques

International Nuclear Information System (INIS)

Dorsch, J.

1997-02-01

The purpose of this study is to provide quantitative data on effective porosity of carbonate rock from the Maynardville Limestone and Copper Ridge Dolomite within Bear Creek Valley based on modern petrophysical techniques. The data will be useful for groundwater-flow and contaminant-flow modeling in the vicinity of the Y-12 Plant on the Oak Ridge Reservation (ORR). Furthermore, the data provides needed information on the amount of interconnected pore space potentially available for operation of matrix diffusion as a transport process within the fractured carbonate rock. A second aspect of this study is to compare effective porosity data based on modern petrophysical techniques to effective porosity data determined earlier by Goldstrand et al. (1995) with a different technique. An added bonus of the study is quantitative data on the bulk density and grain density of dolostone and limestone of the Maynardville Limestone and Copper Ridge Dolomite which might find use for geophysical modeling on the ORR

Environmental Setting and Effects on Water Quality in the Great and Little Miami River Basins, Ohio and Indiana

Science.gov (United States)

Debrewer, Linda M.; Rowe, Gary L.; Reutter, David C.; Moore, Rhett C.; Hambrook, Julie A.; Baker, Nancy T.

2000-01-01

industrial wastewater- treatment and thermoelectric plants, urban runoff, and disposal of solid and hazardous wastes contribute contaminants to surface water and ground water throughout the study area. Surface water and ground water in the Great and Little Miami River Basins are classified as very hard, calcium-magnesium- bicarbonate waters. The major-ion composition and hardness of surface water and ground water reflect extensive contact with the carbonate-rich soils, glacial sediments, and limestone or dolomite bedrock. Dieldrin, endrin, endosulfan II, and lindane are the most commonly reported organochlorine pesticides in streams draining the Great and Little Miami River Basins. Peak concentrations of the her-bicides atrazine and metolachlor in streams commonly are associated with post-application runoff events. Nitrate concentrations in surface water average 3 to 4 mg/L (milligrams per liter) in the larger streams and also show strong seasonal variations related to application periods and runoff events. Ambient iron concentrations in ground water pumped from aquifers in the Great and Little Miami River Basins often exceed the U.S. Environmental Protection Agency Secondary Maximum Contaminant Level (300 micrograms per liter). Chloride concentrations are below aesthetic drinking-water guidelines (250 mg/L), except in ground water pumped from low-yielding Ordovician shale; chloride concentrations in sodium-chloride- rich ground water pumped from the shale bedrock can exceed 1,000 mg/L. Some of the highest average nitrate concentrations in ground water in Ohio and Indiana are found in wells completed in the buried-valley aquifer; these concentrations typically are found in those parts of the sand and gravel aquifer that are not overlain by clay-rich till. Atrazine was the most commonly detected herbicide in private wells. Concentrations of volatile organic compounds in ground water generally were below Federal drinking-water standards, except near areas of known or

Stable and radioactive carbon in Indian soils: implications to soil carbon dynamics

International Nuclear Information System (INIS)

Laskar, A.H.; Yadava, M.G.; Ramesh, R.

2011-01-01

Radiocarbon is a very useful tool to study soil carbon dynamic. The mean residence time of SOC in Indian soils is about a century at the top 0-15 cm, increases linearly to reach values ranging from 2000 to 4000 yrs at a depth of 100 cm. It mainly depends on the clay content indicating that the clay is the main governing factor for SOC stabilization. Stable carbon and oxygen isotopes in soil carbonates and SOC are good proxies for paleoclimate and paleovegetation reconstruction. The present day sub-humid climate in the lower Narmada valley has been established prior to ∼ 3 ka. Two comparatively arid phases around 2.1 and 1.3 ka are recorded by oxygen isotopes of soil carbonates; consistent with other proxy records showing its regional significance

Land-Sparing Opportunities for Solar Energy Development in Agricultural Landscapes: A Case Study of the Great Central Valley, CA, United States.

Science.gov (United States)

Hoffacker, Madison K; Allen, Michael F; Hernandez, Rebecca R

2017-12-19

Land-cover change from energy development, including solar energy, presents trade-offs for land used for the production of food and the conservation of ecosystems. Solar energy plays a critical role in contributing to the alternative energy mix to mitigate climate change and meet policy milestones; however, the extent that solar energy development on nonconventional surfaces can mitigate land scarcity is understudied. Here, we evaluate the land sparing potential of solar energy development across four nonconventional land-cover types: the built environment, salt-affected land, contaminated land, and water reservoirs (as floatovoltaics), within the Great Central Valley (CV, CA), a globally significant agricultural region where land for food production, urban development, and conservation collide. Furthermore, we calculate the technical potential (TWh year -1 ) of these land sparing sites and test the degree to which projected electricity needs for the state of California can be met therein. In total, the CV encompasses 15% of CA, 8415 km 2 of which was identified as potentially land-sparing for solar energy development. These areas comprise a capacity-based energy potential of at least 17 348 TWh year -1 for photovoltaic (PV) and 2213 TWh year -1 for concentrating solar power (CSP). Accounting for technology efficiencies, this exceeds California's 2025 projected electricity demands up to 13 and 2 times for PV and CSP, respectively. Our study underscores the potential of strategic renewable energy siting to mitigate environmental trade-offs typically coupled with energy sprawl in agricultural landscapes.

Distribution and abundance of fungi in the soils of Taylor Valley, Antarctica

Science.gov (United States)

Connell, L.; Redman, R.; Craig, S.; Rodriguez, R.

2006-01-01

The occurrence and distribution of culturable fungi in Taylor Valley, Antarctica was assessed in terms of soil habitat. Soil transects throughout the valley revealed differential habitat utilization between filamentous and non-filamentous (yeast and yeast-like) fungi. In addition, there were significant differences in species distribution patterns with respect to soil pH, moisture, distance from marine coastline, carbon, chlorophyll a, salinity, elevation and solar inputs. Filamentous fungal abundance is most closely associated with habitats having higher pH, and soil moistures. These close associations were not found with yeast and yeast-like fungi demonstrating that yeast and yeast-like fungi utilize a broader range of habitat. An intensive survey of the Victoria Land is necessary to gain a better understanding of their role in soil functioning and nutrient cycling processes. ?? 2006 Elsevier Ltd. All rights reserved.

Measurements of Carbon Dioxide and Carbon Monoxide at High Spatial and Temporal Resolution in an Urban Environment

Science.gov (United States)

Rella, C.; Jacobson, G. A.; Crosson, E.

2011-12-01

The ability to take inventory of critical greenhouse gases such as carbon dioxide and methane and quantify their sources and sinks is essential for understanding the atmospheric drivers to global climate change. "Top down" inversion measurements and models are used to quantify net carbon fluxes into the atmosphere. The overall carbon fluxes are determined by combining remote measurements of carbon dioxide concentrations with complex atmospheric transport models, and these emissions measurements are compared to "bottoms-up" predictions based on detailed inventories of the sources and sinks of carbon, both anthropogenic and biogenic in nature. At smaller distance scales, such as that of a city or even smaller, the basic framework underpinning the inversion modeling technique begins to break down: atmospheric transport models, which are well understood at a length scale of 100 km, work poorly or not at all at a 100m distance scale. Furthermore, the variability of the emissions sources in space (e.g., factories, highways, residences) and time (rush hours, factory shifts and shutdowns, residential energy usage variability during the day and over the year) complicate the interpretation of the measured signals. In this paper we present detailed, high spatial- and temporal-resolution greenhouse gas measurements in Silicon Valley, CA. The results of two experimental campaigns are presented: a 10m urban 'tower' and ground-based mobile mapping measurements. In both campaigns, real-time carbon dioxide data are combined with real-time carbon monoxide measurements to partition the observed CO2 concentrations between anthropogenic and biogenic sources . The urban tower measurements are made continuously over a period of many weeks. The mobile maps of the vicinity of the urban tower are taken repeatedly over a period of several days, and at different times of the day and under different atmospheric conditions, to assess the robustness and repeatability of the maps. Initial

Into the deep: A coarse-grained carbonate turbidite thalweg generated by gigantic submarine chutes

Science.gov (United States)

Mulder, Thierry; Gillet, Hervé; Reijmer, John; Droxler, André; cavailhes, Thibault; Hanquiez, Vincent; Fauquembergue, Kelly; Bujan, Stéphane; Blanck, David; bashah, Sara; Guiastrennec, Léa; Fabregas, Natacha; Recouvreur, Audrey; Seibert, Chloé

2017-04-01

New high-resolution multibeam mapping, in the Southeastern Bahamas, images in exquisite details the southern part of Exuma Sound, and its unchartered transition area to the deep abyssal plain of the Western North Atlantic bounded by the Bahama Escarpment (BE) between San Salvador Island and Samana Cay, referred here to the San Salvador abyssal plain. The transition area is locally referred to as Crooked Island Passage, loosely delineated by Crooked, Long, and Conception Islands, Rum and Samana Cays. Surprisingly in such a pure carbonate landscape, the newly established map reveals the detailed and complex morphology of a giant valley formed by numerous gravity flows originated in Exuma Sound itself, in addition to many secondary slope gullies and smaller tributaries draining the surrounding upper slopes. The valley referred here as the Exuma canyon system starts with a perched valley with low sinuosity, characterized by several flow restrictions and knickpoints initiated by the presence of drowned isolated platforms and merging tributaries. The valley abruptly transforms itself into a deep incised canyon, rivaling the depth of the Colorado Grand Canyon, through two major knickpoints with outsized chutes exceeding several hundred of meters in height, a total of 1600-1800 m. The sudden transformation of the wide valley into a deep narrow canyon, occurring when the flows incised deep into an underlying lower Cretaceous drowned carbonate platform, generates a huge hydraulic jump and creates an enormous plunge pool and related deposits with mechanisms comparable to the ones operating along giant subaerial waterfalls. The high kinetic flow energy, constrained by this narrow and deeply incised canyon, formed, when it is released at its mouth in the abyssal plain, a wide deep-sea channel with well-developed levees and fan, made of coarse-grained carbonate defined layers separated by fine carbonate sediments mixed with fine siliciclastics transported along the BE by the

Polyfluoroalkyl substance exposure in the Mid-Ohio River Valley, 1991–2012

International Nuclear Information System (INIS)

Herrick, Robert L.; Buckholz, Jeanette; Biro, Frank M.; Calafat, Antonia M.; Ye, Xiaoyun; Xie, Changchun; Pinney, Susan M.

2017-01-01

Background: Industrial discharges of perfluorooctanoic acid (PFOA) to the Ohio River, contaminating water systems near Parkersburg, WV, were previously associated with nearby residents' serum PFOA concentrations above US general population medians. Ohio River PFOA concentrations downstream are elevated, suggesting Mid-Ohio River Valley residents are exposed through drinking water. Objectives: Quantify PFOA and 10 other per- and polyfluoroalkyl substances (PFAS) in Mid-Ohio River Valley resident sera collected between 1991 and 2013 and determine whether the Ohio River and Ohio River Aquifer are exposure sources. Methods: We measured eleven PFAS in 1608 sera from 931 participants. Serum PFOA concentration and water source associations were assessed using linear mixed-effects models. We estimated between-sample serum PFOA using one-compartment pharmacokinetics for participants with multiple samples. Results: In serum samples collected as early as 1991, PFOA (median = 7.6 ng/mL) was detected in 99.9% of sera; 47% had concentrations greater than US population 95th percentiles. Five other PFAS were detected in greater than 82% of samples; median other PFAS concentrations were similar to the US general population. Serum PFOA was significantly associated with water source, sampling year, age at sampling, tap water consumption, pregnancy, gravidity and breastfeeding. Serum PFOA was 40–60% lower with granular activated carbon (GAC) use. Repeated measurements and pharmacokinetics suggest serum PFOA peaked 2000–2006 for participants using water without GAC treatment; where GAC was used, serum PFOA concentrations decreased from 1991 to 2012. Conclusions: Mid-Ohio River Valley residents appear to have PFOA, but not other PFAS, serum concentrations above US population levels. Drinking water from the Ohio River and Ohio River Aquifer, primarily contaminated by industrial discharges 209–666 km upstream, is likely the primary exposure source. GAC treatment of drinking

A landscape scale valley confinement algorithm: Delineating unconfined valley bottoms for geomorphic, aquatic, and riparian applications

Science.gov (United States)

David E. Nagel; John M. Buffington; Sharon L. Parkes; Seth Wenger; Jaime R. Goode

2014-01-01

Valley confinement is an important landscape characteristic linked to aquatic habitat, riparian diversity, and geomorphic processes. This report describes a GIS program called the Valley Confinement Algorithm (VCA), which identifies unconfined valleys in montane landscapes. The algorithm uses nationally available digital elevation models (DEMs) at 10-30 m resolution to...

Chemical composition and source apportionment of aerosol over the Klang valley

International Nuclear Information System (INIS)

Shamsiah Abdul Rahman; Mohd Suhaimi Hamzah; Abdul Khalik Wood; Nazaratul Ashifa Abdullah Salim; Mohd Suhaimi Elias; Eswiza Sanuri

2009-01-01

This paper reports the study of aerosol chemical composition of fine particles (PM 2.5) and possible sources of air pollution over the Klang Valley, Kuala Lumpur, based on the samples collected for a period of 6 years from July 2000 to Jun 2006. Samples collected were measured for mass, black carbon and elemental content of Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Br and Pb. The fine aerosol mass concentration ranged from 11 - 110 ?g/m3. Black carbon is the major component of the fine aerosol with the weight fraction of 20%, whilst S is the major elemental content with the weight fraction about 5% as relative to the fine particle mass. The factor analysis method, positive matrix factorization (PMF) was then used to confirm the possible sources. The result of PMF analysis produced five-factor sources that contribute to the fine particles in the Klang Valley area. The five factors represent sea spray, industry, motor vehicles, smoke and soil. Motor vehicle is the main source of particulates in the area, with an average contribution of 51% of the fine mass concentration, followed by industry, smoke, sea spray and soil, with average contribution of 28%, 14%, 3.6% and 2.1%, respectively. (Author)

Measurements of Carbon Dioxide, Carbon Monoxide, and Other Related Tracers at High Spatial and Temporal Resolution in an Urban Environment

Science.gov (United States)

Rella, C.; Jacobson, G.

2012-04-01

The ability to quantify the sources and sinks of carbon dioxide on the urban scale is essential for understanding the atmospheric drivers to global climate change. In the 'top-down' approach, overall carbon fluxes are determined by combining remote measurements of carbon dioxide concentrations with complex atmospheric transport models, and these emissions measurements are compared to "bottoms-up" predictions based on detailed inventories of the sources and sinks of carbon, both anthropogenic and biogenic in nature. This approach, which has been proven to be effective at continental scales, becomes challenging to implement at the urban scale, due to poorly understood micrometeorological atmospheric transport models and high variability of the emissions sources in space (e.g., factories, highways, residences) and time (rush hours, factory shifts and shutdowns, residential energy usage variability during the day and over the year). New measurement and analysis techniques are required to make sense of the carbon dioxide signal in cities. Here we present detailed, high spatial- and temporal-resolution greenhouse gas measurements in Silicon Valley in California. The synthesis of two experimental campaigns is presented: real-time measurements from two ten-meter urban 'towers,' and ground-based mobile mapping measurements. Real-time carbon dioxide data from a nine-month period are combined with real-time carbon monoxide, methane, acetylene, and carbon 13 measurements to partition the observed CO2 concentrations between different anthropogenic sectors (e.g., transport, residential) and biogenic sources. The carbon monoxide to carbon dioxide ratio is shown to vary over more than a factor of two from season to season or even from day to night, indicating rapid and frequent shifts in the balance between different carbon dioxide sources. Clear differences are seen between the two urban sites, which are separated by 7 km. Further information is given by the carbon 13 signature

Small martian valleys: Pristine and degraded morphology

International Nuclear Information System (INIS)

Baker, V.R.; Partridge, J.B.

1986-01-01

The equatorial heavily cratered uplands of Mars are dissected by two classes of small valleys that are intimately associated in compound networks. Pristine valleys with steep valley walls preferentially occupy downstream portions of compound basins. Degraded valleys with eroded walls are laterally more extensive and have higher drainage densities than pristine valleys. Morphometric and crater-counting studies indicate that relatively dense drainage networks were emplaced on Mars during the heavy bombardment about 4.0 b.y. ago. Over a period of approximately 10 8 years, these networks were degraded and subsequently invaded by headwardly extending pristine valleys. The pristine valleys locally reactivated the compound networks, probably through sapping processes dependent upon high water tables. Fluvial activity in the heavily cratered uplands generally ceased approximately 3.8--3.9 b.y. ago, coincident with the rapid decline in cratering rates. The relict compound valleys on Mars are morphometrically distinct from most terrestrial drainage systems. The differences might be caused by a Martian valley formation episode characterized by hyperaridity, by inadequate time for network growth, by very permeable rock types, or by a combination of factors

Geologic summary of the Owens Valley drilling project, Owens and Rose Valleys, Inyo County, California

International Nuclear Information System (INIS)

Schaer, D.W.

1981-07-01

The Owens Valley Drilling Project consists of eight drill holes located in southwest Inyo County, California, having an aggregate depth of 19,205 feet (5853 m). Project holes penetrated the Coso Formation of upper Pliocene or early Pleistocene age and the Owens Lake sand and lakebed units of the same age. The project objective was to improve the reliability of uranium-potential-resource estimates assigned to the Coso Formation in the Owens Valley region. Uranium-potential-resource estimates for this area in $100 per pound U 3 O 8 forward-cost-category material have been estimatd to be 16,954 tons (15,384 metric tons). This estimate is based partly on project drilling results. Within the Owens Valley project area, the Coso Formation was encountered only in the Rose Valley region, and for this reason Rose Valley is considered to be the only portion of the project area favorable for economically sized uranium deposits. The sequence of sediments contained in the Owens Valley basin is considered to be largely equivalent but lithologically dissimilar to the Coso Formation of Haiwee Ridge and Rose Valley. The most important factor in the concentration of significant amounts of uranium in the rock units investigated appears to be the availability of reducing agents. Significant amounts of reductants (pyrite) were found in the Coso Formation. No organic debris was noted. Many small, disconnected uranium occurrences, 100 to 500 ppM U 3 O 8 , were encountered in several of the holes

Valley dependent transport in graphene L junction

Science.gov (United States)

Chan, K. S.

2018-05-01

We studied the valley dependent transport in graphene L junctions connecting an armchair lead and a zigzag lead. The junction can be used in valleytronic devices and circuits. Electrons injected from the armchair lead into the junction is not valley polarized, but they can become valley polarized in the zigzag lead. There are Fermi energies, where the current in the zigzag lead is highly valley polarized and the junction is an efficient generator of valley polarized current. The features of the valley polarized current depend sensitively on the widths of the two leads, as well as the number of dimers in the armchair lead, because this number has a sensitive effect on the band structure of the armchair lead. When an external potential is applied to the junction, the energy range with high valley polarization is enlarged enhancing its function as a generator of highly valley polarized current. The scaling behavior found in other graphene devices is also found in L junctions, which means that the results presented here can be extended to junctions with larger dimensions after appropriate scaling of the energy.

Application of apatite fission tract analysis to problems of Mississippi Valley-type Pb-Zn ore genesis

International Nuclear Information System (INIS)

Arne, D.C.; Duddy, I.R.; Green, P.F.; Lambert, I.B.

1987-01-01

Epigenetic, carbonate-hosted Pb-Zn mineralization of the Mississippi Valley-Type (MVT) is considered to form from warm basinal brines in the temperature range 50-200 deg.C. A variety of genetic fluid flow models have been proposed to explain MVT mineralization, but all suffer from a lack of constraint concerning the timing of ore formation. Fission tracks in apatite resulting from the spontaneous decay of trace amounts of 238 U are thermally unstable over the range of temperatures proposed for MVT ore formation, and may therefore record thermal events related to Pb-Zn mineralization provided sufficient time is allowed for track annealing to occur. Zinc mineralization in Devonian carbonates of the Lennard Shelf, northwest Australia is also considered to be of the Mississippi Valley-type. Mean apatite ages from Precambrian basement and from Devonian carbonates generally average 300Ma. Studies of well sequences indicate a period of uplift for the Lennard Shelf area around the Late Triassic/Early Jurassic. For carbonate outcrop samples, a thermal history is proposed involving burial in the Late Paleozoic/Early Mesozoic followed by uplift and cooling from peak temperatures around 70 deg.C. No difference in apatite annealing effects are observed in the vicinity of zinc mineralization. Coupled with other evidence, this suggests that the mineralizing episode was of short duration given temperatures of ore formation in the range 70-110 deg.C indicated by fluid inclusion homogenization temperatures. 3 refs

Soils of wet valleys in the Larsemann Hills and Vestfold Hills oases (Princess Elizabeth Land, East Antarctica)

Science.gov (United States)

Mergelov, N. S.

2014-09-01

The properties and spatial distribution of soils and soil-like bodies in valleys of the coastal Larsemann Hills and Vestfold Hills oases—poorly investigated in terms of the soil areas of East Antarctica—are discussed. In contrast to Dry Valleys—large continental oases of Western Antarctica—the studied territory is characterized by the presence of temporarily waterlogged sites in the valleys. It is argued that the deficit of water rather than the low temperature is the major limiting factor for the development of living organisms and the pedogenesis on loose substrates. The moisture gradients in the surface soil horizons explain the spatial distribution of the different soils and biotic complexes within the studied valleys. Despite the permanent water-logging of the deep suprapermafrost horizons of most of the soils in the valleys, no gley features have been identified in them. The soils of the wet valleys in the Larsemann Hills oasis do not contain carbonates. They have a slightly acid or neutral reaction. The organic carbon and nitrogen contents are mainly controlled by the amount of living and dead biomass rather than by the humic substances proper. The larger part of the biomass is concentrated inside the mineral soil matrix rather than on the soil surface. The stresses caused by surface drying, strong winds, and ultraviolet radiation prevent the development of organisms on the surface of the soil and necessitate the search for shelter within the soil fine earth material (endoedaphic niche) or under the gravelly pavement (hypolithic niche). In the absence of higher plants, humified products of their decomposition, and rainwater that can wash the soil profile and upon the low content of silt and clay particles in the soil material, "classical" soil horizons are not developed. The most distinct (and, often, the only diagnosed) products of pedogenesis in these soils are represented by organomineral films on the surface of mineral particles.

Eocene extension in Idaho generated massive sediment floods into Franciscan trench and into Tyee, Great Valley, and Green River basins

Science.gov (United States)

Dumitru, Trevor A.; Ernst, W.G.; Wright, James E.; Wooden, Joseph L.; Wells, Ray E.; Farmer, Lucia P.; Kent, Adam J.R.; Graham, Stephan A.

2013-01-01

The Franciscan Complex accretionary prism was assembled during an ∼165-m.y.-long period of subduction of Pacific Ocean plates beneath the western margin of the North American plate. In such fossil subduction complexes, it is generally difficult to reconstruct details of the accretion of continent-derived sediments and to evaluate the factors that controlled accretion. New detrital zircon U-Pb ages indicate that much of the major Coastal belt subunit of the Franciscan Complex represents a massive, relatively brief, surge of near-trench deposition and accretion during Eocene time (ca. 53–49 Ma). Sediments were sourced mainly from the distant Idaho Batholith region rather than the nearby Sierra Nevada. Idaho detritus also fed the Great Valley forearc basin of California (ca. 53–37 Ma), the Tyee forearc basin of coastal Oregon (49 to ca. 36 Ma), and the greater Green River lake basin of Wyoming (50–47 Ma). Plutonism in the Idaho Batholith spanned 98–53 Ma in a contractional setting; it was abruptly superseded by major extension in the Bitterroot, Anaconda, Clearwater, and Priest River metamorphic core complexes (53–40 Ma) and by major volcanism in the Challis volcanic field (51–43 Ma). This extensional tectonism apparently deformed and uplifted a broad region, shedding voluminous sediments toward depocenters to the west and southeast. In the Franciscan Coastal belt, the major increase in sediment input apparently triggered a pulse of massive accretion, a pulse ultimately controlled by continental tectonism far within the interior of the North American plate, rather than by some tectonic event along the plate boundary itself.

Subsidence and Rebound in California's Central Valley: Effects of Pumping, Geology, and Precipitation

Science.gov (United States)

Farr, T. G.; Fairbanks, A.

2017-12-01

Recent rains in California caused a pause, and even a reversal in some areas, of the subsidence that has plagued the Central Valley for decades. The 3 main drivers of surface deformation in the Central Valley are: Subsurface hydro-geology, precipitation and surface water deliveries, and groundwater pumping. While the geology is relatively fixed in time, water inputs and outputs vary greatly both in time and space. And while subsurface geology and water inputs are reasonably well-known, information about groundwater pumping amounts and rates is virtually non-existent in California. We have derived regional maps of surface deformation in the region for the period 2006 - present which allow reconstruction of seasonal and long-term changes. In order to understand the spatial and temporal patterns of subsidence and rebound in the Central Valley, we have been compiling information on the geology and water inputs and have attempted to infer pumping rates using maps of fallowed fields and published pumping information derived from hydrological models. In addition, the spatial and temporal patterns of hydraulic head as measured in wells across the region allow us to infer the spatial and temporal patterns of groundwater pumping and recharge more directly. A better understanding of how different areas (overlying different stratigraphy) of the Central Valley respond to water inputs and outputs will allow a predictive capability, potentially defining sustainable pumping rates related to water inputs. * work performed under contract to NASA and the CA Dept. of Water Resources

Microscopic Identification of Prokaryotes in Modern and Ancient Halite, Saline Valley and Death Valley, California

Science.gov (United States)

Schubert, Brian A.; Lowenstein, Tim K.; Timofeeff, Michael N.

2009-06-01

Primary fluid inclusions in halite crystallized in Saline Valley, California, in 1980, 2004-2005, and 2007, contain rod- and coccoid-shaped microparticles the same size and morphology as archaea and bacteria living in modern brines. Primary fluid inclusions from a well-dated (0-100,000 years), 90 m long salt core from Badwater Basin, Death Valley, California, also contain microparticles, here interpreted as halophilic and halotolerant prokaryotes. Prokaryotes are distinguished from crystals on the basis of morphology, optical properties (birefringence), and uniformity of size. Electron micrographs of microparticles from filtered modern brine (Saline Valley), dissolved modern halite crystals (Saline Valley), and dissolved ancient halite crystals (Death Valley) support in situ microscopic observations that prokaryotes are present in fluid inclusions in ancient halite. In the Death Valley salt core, prokaryotes in fluid inclusions occur almost exclusively in halite precipitated in perennial saline lakes 10,000 to 35,000 years ago. This suggests that trapping and preservation of prokaryotes in fluid inclusions is influenced by the surface environment in which the halite originally precipitated. In all cases, prokaryotes in fluid inclusions in halite from the Death Valley salt core are miniaturized (<1 μm diameter cocci, <2.5 μm long, very rare rod shapes), which supports interpretations that the prokaryotes are indigenous to the halite and starvation survival may be the normal response of some prokaryotes to entrapment in fluid inclusions for millennia. These results reinforce the view that fluid inclusions in halite and possibly other evaporites are important repositories of microbial life and should be carefully examined in the search for ancient microorganisms on Earth, Mars, and elsewhere in the Solar System.

Topological Valley Transport in Two-dimensional Honeycomb Photonic Crystals.

Science.gov (United States)

Yang, Yuting; Jiang, Hua; Hang, Zhi Hong

2018-01-25

Two-dimensional photonic crystals, in analogy to AB/BA stacking bilayer graphene in electronic system, are studied. Inequivalent valleys in the momentum space for photons can be manipulated by simply engineering diameters of cylinders in a honeycomb lattice. The inequivalent valleys in photonic crystal are selectively excited by a designed optical chiral source and bulk valley polarizations are visualized. Unidirectional valley interface states are proved to exist on a domain wall connecting two photonic crystals with different valley Chern numbers. With the similar optical vortex index, interface states can couple with bulk valley polarizations and thus valley filter and valley coupler can be designed. Our simple dielectric PC scheme can help to exploit the valley degree of freedom for future optical devices.

Geologic characterization report for the Paradox Basin Study Region, Utah Study Areas. Volume 6. Salt Valley

International Nuclear Information System (INIS)

1984-12-01

Surface landforms in the Salt Valley Area are generally a function of the Salt Valley anticline and are characterized by parallel and subparallel cuestaform ridges and hogbacks and flat valley floors. The most prominent structure in the Area is the Salt Valley anticline. Erosion resulting from the Tertiary uplift of the Colorado Plateau led to salt dissolution and subsequent collapse along the crest of the anticline. Continued erosion removed the collapse material, forming an axial valley along the crest of the anticline. Paleozoic rocks beneath the salt bearing Paradox Formation consist of limestone, dolomite, sandstone, siltstone and shale. The salt beds of the Paradox Formation occur in distinct cycles separated by an interbed sequence of anhydrite, carbonate, and clastic rocks. The Paradox Formation is overlain by Pennsylvanian limestone; Permian sandstone; and Mesozoic sandstone, mudstone, conglomerate and shale. No earthquakes have been reported in the Area during the period of the historic record and contemporary seismicity appears to be diffusely distributed, of low level and small magnitude. The upper unit includes the Permian strata and upper Honaker Trail Formation. The current data base is insufficient to estimate ground-water flow rates and directions in this unit. The middle unit includes the evaporites in the Paradox Formation and no laterally extensive flow systems are apparent. The lower unit consists of the rocks below the Paradox Formation where permeabilities vary widely, and the apparent flow direction is toward the west. 108 refs., 39 figs., 9 tabs

Estimation of the emission polluting agents by Motorcycles in the Aburra Valley

International Nuclear Information System (INIS)

Giraldo Aristizabal, William Alonso; Toro Gomez, Maria Victoria

2008-01-01

The motorcycle is considered a generating movable polluting gas source like the volatile organic compounds and the carbon monoxide that are released to the atmosphere. In Colombia they have registered in the last years a high increase in the use of this type of vehicles having increased therefore the emissions, which has contributed with the deterioration of the quality of the air of the Valley of Aburra. In the other hand environmental regulation is recent and has not applied rigorously yet. Consequently and having like reference international Literature and the measurements in slow motion or minimum march, made by the Metropolitan Area, between January and March of 2006, factors of emission for carbon monoxide and hydrocarbons for the estimation of the impact in the city.

Radiological assessment of the Rhone valley. Final report related to the ground environment

International Nuclear Information System (INIS)

Roussel-Debet, S.; Saey, L.; Mourier, D.; Salaun, G.

2012-01-01

This report presents and comments the results obtained during a ground radiological survey performed in the Rhone valley from May 2009 to end of 2011. It recalls the general sampling and analysis strategy, in terms of objectives, locations, samples to measure tritium and carbon 14, and specific samples. It presents and discusses results obtained for tritium and carbon 14, and notably measurements obtained in boar meat. Other commented results are those obtained by gamma spectrometry on farm products (measurements of natural and artificial radionuclides), by analysis of milk products, and by specific samplings and analysis (bio-indicators in the vicinity of Marcoule, Camargue sands and beaches, rice field grounds, measurements performed after the Fukushima accident)

Trend in Air Quality of Kathmandu Valley: A Satellite, Observation and Modelling Perspective

Science.gov (United States)

Mahapatra, P. S.; Praveen, P. S.; Adhikary, B.; Panday, A. K.; Putero, D.; Bonasoni, P.

2016-12-01

Kathmandu (floor area of 340 km2) in Nepal is considered to be a `hot spot' of urban air pollution in South Asia. Its structure as a flat basin surrounded by tall mountains provides a unique case study for analyzing pollution trapped by topography. Only a very small number of cities with similar features have been studied extensively including Mexico and Santiago-de-Chile. This study presents the trend in satellite derived Aerosol Optical Depth (AOD) from MODIS AQUA and TERRA (3x3km, Level 2) over Kathmandu from 2000 to 2015. Trend analysis of AOD shows 35% increase during the study period. Determination of the background pollution would reveal the contribution of only Kathmandu Valley for the observation period. For this, AOD at 1340m altitude outside Kathmandu, but nearby areas were considered as background. This analysis was further supported by investigating AOD at different heights around Kathmandu as well as determining AOD from CALIPSO vertical profiles. These analysis suggest that background AOD contributed 30% in winter and 60% in summer to Kathmandu Valley's observed AOD. Thereafter the background AOD was subtracted from total Kathmandu AOD to determine contribution of only Kathmandu Valley's AOD. Trend analysis of only Kathmandu Valley AOD (subtracting background AOD) suggested an increase of 50% during the study period. Further analysis of Kathmandu's visibility and AOD suggest profound role of background AOD on decreasing visibility. In-situ Black Carbon (BC) mass concentration measurements (BC being used as a proxy for surface observations) at two sites within Kathmandu valley have been analyzed. Kathmandu valley lacks long term trends of ambient air quality measurement data. Therefore, surface observations would be coupled with satellite measurements for understanding the urban air pollution scenario. Modelling studies to estimate the contribution of background pollution to Kathmandu's own pollution as well as the weekend effect on air quality will

Luminescence dating of paleolake deltas and glacial deposits in Garwood Valley, Antarctica: Implications for climate, Ross ice sheet dynamics, and paleolake duration

Science.gov (United States)

Levy, Joseph S.; Rittenour, Tammy M.; Fountain, Andrew G.; O'Connor, Jim E.

2017-01-01

The formation of perched deltas and other lacustrine deposits in the McMurdo Dry Valleys of Antarctica is widely considered to be evidence of valley-filling lakes dammed by the grounded Ross Sea ice sheet during the local Last Glacial Maximum, with lake drainage interpreted as a record of grounding line retreat. We used luminescence dating to determine the age of paleolake deltas and glacial tills in Garwood Valley, a coastal dry valley that opens to the Ross Sea. Luminescence ages are stratigraphically consistent with radiocarbon results from algal mats within the same delta deposits but suggest radiocarbon dates from lacustrine carbonates may overestimate deposit ages by thousands of years. Results suggest that late Holocene delta deposition into paleolake Howard in Garwood Valley persisted until ca. 3.5 ka. This is significantly younger than the date when grounded ice is thought to have retreated from the Ross Sea. Our evidence suggests that the local, stranded ice-cored till topography in Garwood Valley, rather than regional ice-sheet dynamics, may have controlled lake levels for some McMurdo Dry Valleys paleolakes. Age control from the supraglacial Ross Sea drift suggests grounding and up-valley advance of the Ross Sea ice sheet into Garwood valley during marine oxygen isotope stage (MIS) 4 (71–78 ka) and the local Last Glacial Maximum (9–10 ka). This work demonstrates the power of combining luminescence dating with existing radiocarbon data sets to improve understanding of the relationships among paleolake formation, glacial position, and stream discharge in response to climate change.

Mechanical control over valley magnetotransport in strained graphene

Energy Technology Data Exchange (ETDEWEB)

Ma, Ning, E-mail: maning@stu.xjtu.edu.cn [Department of Physics, MOE Key Laboratory of Advanced Transducers and Intelligent Control System, Taiyuan University of Technology, Taiyuan 030024 (China); Department of Applied Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang, Shengli, E-mail: zhangsl@mail.xjtu.edu.cn [Department of Applied Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049 (China); Liu, Daqing, E-mail: liudq@cczu.edu.cn [School of Mathematics and Physics, Changzhou University, Changzhou 213164 (China)

2016-05-06

Recent experiments report that the graphene exhibits Landau levels (LLs) that form in the presence of a uniform strain pseudomagnetic field with magnitudes up to hundreds of tesla. We further reveal that the strain removes the valley degeneracy in LLs, and leads to a significant valley polarization with inversion symmetry broken. This accordingly gives rise to the well separated valley Hall plateaus and Shubnikov–de Haas oscillations. These effects are absent in strainless graphene, and can be used to generate and detect valley polarization by mechanical means, forming the basis for the new paradigm “valleytronics” applications. - Highlights: • We explore the mechanical strain effects on the valley magnetotransport in graphene. • We analytically derive the dc collisional and Hall conductivities under strain. • The strain removes the valley degeneracy in Landau levels. • The strain causes a significant valley polarization with inversion symmetry broken. • The strain leads to the well separated valley Hall and Shubnikov–de Haas effects.

Climate change and the Lower Fraser Valley. rev. ed.

International Nuclear Information System (INIS)

Taylor, E.; Langlois, D.

2000-01-01

The climatic changes that are expected to occur in British Columbia's Lower Fraser Valley over the next century were described in this report which included information about the science of climate change and the development of global climate models that provide estimates of global climate for the coming century. The confidence that scientists have in these models was reflected in the fact that most can simulate the important seasonal and geographical large scale features of the global climate, and that many of the large scale changes that are effected by greenhouse gas concentrations can be explained in terms of physical processes which operate around the world. The models also reproduce with reasonable accuracy the variations of climate such as the El Nino phenomena., the cooling due to the Mount Pinatubo eruption in 1991 and the global warming that occurred over the past 100 years. Three climate stations were analyzed in this study to assess the climate change of the Valley. Climatic change is influenced by increased concentrations of greenhouse gases in the atmosphere which in turn cause accelerated global warming. Scientists generally believe that the combustion of fossil fuels and other human activities are a major reason for the increased concentration of carbon dioxide. Plant respiration and the decomposition of organic matter releases 10 times more CO 2 than that released anthropogenically, but these releases are in balance with plant photosynthesis. The rate of warming in the Lower Fraser Valley is uncertain, but climate models suggest it could be about 3 to 4 degrees warming with wetter winters and drier summers by the end of the century. The Valley currently has mild temperatures and high precipitation because of its proximity to the Pacific Oceans and the surrounding mountains. Global warming can have an impact on sea levels along the coast, spring flooding, summer drought, coastal ecosystems, air quality, occurrences of forest fires, and recreation

Mapping carbon flux uncertainty and selecting optimal locations for future flux towers in the Great Plains

Science.gov (United States)

Gu, Yingxin; Howard, Daniel M.; Wylie, Bruce K.; Zhang, Li

2012-01-01

Flux tower networks (e. g., AmeriFlux, Agriflux) provide continuous observations of ecosystem exchanges of carbon (e. g., net ecosystem exchange), water vapor (e. g., evapotranspiration), and energy between terrestrial ecosystems and the atmosphere. The long-term time series of flux tower data are essential for studying and understanding terrestrial carbon cycles, ecosystem services, and climate changes. Currently, there are 13 flux towers located within the Great Plains (GP). The towers are sparsely distributed and do not adequately represent the varieties of vegetation cover types, climate conditions, and geophysical and biophysical conditions in the GP. This study assessed how well the available flux towers represent the environmental conditions or "ecological envelopes" across the GP and identified optimal locations for future flux towers in the GP. Regression-based remote sensing and weather-driven net ecosystem production (NEP) models derived from different extrapolation ranges (10 and 50%) were used to identify areas where ecological conditions were poorly represented by the flux tower sites and years previously used for mapping grassland fluxes. The optimal lands suitable for future flux towers within the GP were mapped. Results from this study provide information to optimize the usefulness of future flux towers in the GP and serve as a proxy for the uncertainty of the NEP map.

Superfund Record of Decision (EPA Region 9): North Hollywood/Burbank Well Field Area 1, San Fernando Valley Site, California (first remedial action), September 1987. Final report

Energy Technology Data Exchange (ETDEWEB)

1987-09-24

The North Hollywood - Burbank Well Field (NHBWF) is located within the San Fernando Valley Ground Water basin, which can provide drinking water for approximately 500,000 people residing in the San Fernando Valley and Los Angeles. In 1980 TCE and PCE were discovered in 25% of DWP's wells. In July 1981, DWP and the Southern California Association of Governments began a two-year study funded by EPA. The study revealed the occurrence of ground-water contamination plume patterns that are spreading toward the southeast. The primary contaminant of concern to the ground-water is TCE with PCE and other VOCs present. The selected remedial action for the site is ground-water pump and treatment using aeration and granular-activated-carbon - air-filtering units, with discharge to the DWP Pumping Station for chlorination and distribution. Spent carbon will be removed and replaced with fresh carbon, with the spent carbon scheduled either for disposal or regeneration. The estimated capital cost for this remedial action is $2,192,895 with present worth OandM of $2,284,105.

Research and application of AMT method in Happiness valley district in Namibia

International Nuclear Information System (INIS)

Yu Xiang; Zhang Ruliang; Yao Shancong; Fan Honghai; Wang Shengyun

2013-01-01

There are great challenges and difficulties in uranium geology work because of large area grass covered land and few outcrops in Happiness valley district in Namibia. To overcome the problems above, AMT method is undertaken to carry out profile investigation. After finding out electric parameters, different lithologic interfaces were divided, two fracture zones and one anticline structure were, this works laid the ground for the exploration of uranium deposit in Namibia and shew that AMT method is an effective one in finding underground structures. (authors)

Cave Tourism: The Potential of Asar Cave as a Natural Tourism Asset at Lenggong Valley, Perak

Directory of Open Access Journals (Sweden)

Rindam Main

2014-01-01

Full Text Available The Lenggong Valley, from a standpoint of natural tourism research, presents strengths, weaknesses, opportunities and challenges that can be utilized to help increase the opportunities for the local community to increase their standard of living. Asar Cave comprises one of the caves that are found in Lenggong. A series of external studies have been done on Asar Cave in order to measure its potential for natural tourism in Lenggong. The objective of this study is to discuss caves as a natural resource that has great potential in the growth of the economy of the residents of the Lenggong Valley. Marketing caves as a source of nature tourism helps the government’s achievements in National Key Result Areas, apart from being a form of environmental control as well as helping to increase awareness about environmental education, specifically those associated with caves. The research results find that SWOT analysis presents huge potential for caves to become a source of nature tourism development in Lenggong. Great potential can also be seen from a standpoint of increasing the standard of living of its residents through their involvement in the tourism sector based on local natural assets.

The geochemistry of groundwater resources in the Jordan Valley: The impact of the Rift Valley brines

Science.gov (United States)

Farber, E.; Vengosh, A.; Gavrieli, I.; Marie, Amarisa; Bullen, T.D.; Mayer, B.; Polak, A.; Shavit, U.

2007-01-01

The chemical composition of groundwater in the Jordan Valley, along the section between the Sea of Galilee and the Dead Sea, is investigated in order to evaluate the origin of the groundwater resources and, in particular, to elucidate the role of deep brines on the chemical composition of the regional groundwater resources in the Jordan Valley. Samples were collected from shallow groundwater in research boreholes on two sites in the northern and southern parts of the Jordan Valley, adjacent to the Jordan River. Data is also compiled from previous published studies. Geochemical data (e.g., Br/Cl, Na/Cl and SO4/Cl ratios) and B, O, Sr and S isotopic compositions are used to define groundwater groups, to map their distribution in the Jordan valley, and to evaluate their origin. The combined geochemical tools enabled the delineation of three major sources of solutes that differentially affect the quality of groundwater in the Jordan Valley: (1) flow and mixing with hypersaline brines with high Br/Cl (>2 ?? 10-3) and low Na/Cl (shallow saline groundwaters influenced by brine mixing exhibit a north-south variation in their Br/Cl and Na/Cl ratios. This chemical trend was observed also in hypersaline brines in the Jordan valley, which suggests a local mixing process between the water bodies. ?? 2007 Elsevier Ltd. All rights reserved.

Wintertime particulate pollution episodes in an urban valley of the Western US: a case study

Science.gov (United States)

Chen, L.-W. A.; Watson, J. G.; Chow, J. C.; Green, M. C.; Inouye, D.; Dick, K.

2012-11-01

This study investigates the causes of elevated PM2.5 episodes and potential exceedences of the US National Ambient Air Quality Standards (NAAQS) in Truckee Meadows, Nevada, an urban valley of the Western US, during winter 2009/2010, an unusually cold and snowy winter. Continuous PM2.5 mass and time-integrated chemical speciation data were acquired from a central valley monitoring site, along with meteorological measurements from nearby sites. All nine days with PM2.5 > 35 μg m-3 showed 24-h average temperature inversion of 1.5-4.5 °C and snow cover of 8-18 cm. Stagnant atmospheric conditions limited wind ventilation while highly reflective snow cover reduced daytime surface heating creating persistent inversion. Elevated ammonium nitrate (NH4NO3) and water associated with it are found to be main reasons for the PM2.5 exceedances. An effective-variance chemical mass balance (EV-CMB) receptor model using locally-derived geological profiles and inorganic/organic markers confirmed secondary NH4NO3 (27-37%), residential wood combustion (RWC; 11-51%), and diesel engine exhaust (7-22%) as the dominant PM2.5 contributors. Paved road dust and de-icing materials were minor, but detectable contributors. RWC is a more important source than diesel for organic carbon (OC), but vice versa for elemental carbon (EC). A majority of secondary NH4NO3 is also attributed to RWC and diesel engines (including snow removal equipment) through oxides of nitrogen (NOx) emissions from these sources. Findings from this study may apply to similar situations experienced by other urban valleys.

The understanding of the formation of valleys and its implication on site characterization: Moredalen and Pukedalen, south-eastern Sweden

International Nuclear Information System (INIS)

Tiren, Sven A.; Waenstedt, Stefan; Straeng, Thomas

2010-11-01

In south-eastern Sweden, there are a number of over-deepened narrow valleys, more than 20 m deep, formed in Precambrian bedrock located above the highest post-glacial shoreline. Canyon-like valleys, called 'kursu' or kursu valleys, are generally interpreted to be formed by glaciofluvial erosion. An example of such a valley is Moredalen, a canyon in the Fennoscandian Shield, which has an implication on site selection for radioactive waste disposal. There are also more open over-deepened valleys along which sub-glacial flow has occurred, e.g. Pukedalen. The main part of this paper discusses a combined geological and geophysical investigation of Moredalen, with the aim to investigate possible reasons for the formation of such an unusual feature formed in acid vulcanite and foliated tonalitic to granodioritic rocks. Moredalen is a marked, approximately 7 km long, E-W striking valley that cuts through a plateau (c. 140 m a.s.l.), and an elevated block of the sub-Cambrian peneplain. Glaciofluvial sediments can be found up-streams where the canyon widens to the west. Just east of the valley is a larger delta deposited at the highest post-glacial shoreline (c. 105 m a.s.l). Further east of, and in line with the Moredalen valley there is an esker. Rock debris in the valley is angular. Pukedalen is a northwest-southeast trending valley incised in massive granite. The valley is in its northern parts relatively open and becomes narrow in its south-eastern part having partly a vertical south-western wall. Rock surfaces are smooth along the valley and rock debris in the valley consists generally of rounded blocks. In line with Pukedalen, on both sides at great distances though, there are eskers. Geomorphological features of this kind indicate certain characteristics of the bedrock that need to be considered during safety analysis of repositories for nuclear waste. The distinct weakness zones along which the kursu-valleys are formed create prominent transport paths for

The understanding of the formation of valleys and its implication on site characterization: Moredalen and Pukedalen, south-eastern Sweden

Energy Technology Data Exchange (ETDEWEB)

Tiren, Sven A.; Waenstedt, Stefan; Straeng, Thomas (GEOSIGMA AB (Sweden))

2010-11-15

In south-eastern Sweden, there are a number of over-deepened narrow valleys, more than 20 m deep, formed in Precambrian bedrock located above the highest post-glacial shoreline. Canyon-like valleys, called 'kursu' or kursu valleys, are generally interpreted to be formed by glaciofluvial erosion. An example of such a valley is Moredalen, a canyon in the Fennoscandian Shield, which has an implication on site selection for radioactive waste disposal. There are also more open over-deepened valleys along which sub-glacial flow has occurred, e.g. Pukedalen. The main part of this paper discusses a combined geological and geophysical investigation of Moredalen, with the aim to investigate possible reasons for the formation of such an unusual feature formed in acid vulcanite and foliated tonalitic to granodioritic rocks. Moredalen is a marked, approximately 7 km long, E-W striking valley that cuts through a plateau (c. 140 m a.s.l.), and an elevated block of the sub-Cambrian peneplain. Glaciofluvial sediments can be found up-streams where the canyon widens to the west. Just east of the valley is a larger delta deposited at the highest post-glacial shoreline (c. 105 m a.s.l). Further east of, and in line with the Moredalen valley there is an esker. Rock debris in the valley is angular. Pukedalen is a northwest-southeast trending valley incised in massive granite. The valley is in its northern parts relatively open and becomes narrow in its south-eastern part having partly a vertical south-western wall. Rock surfaces are smooth along the valley and rock debris in the valley consists generally of rounded blocks. In line with Pukedalen, on both sides at great distances though, there are eskers. Geomorphological features of this kind indicate certain characteristics of the bedrock that need to be considered during safety analysis of repositories for nuclear waste. The distinct weakness zones along which the kursu-valleys are formed create prominent transport paths for

27 CFR 9.27 - Lime Kiln Valley.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Lime Kiln Valley. 9.27... OF THE TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.27 Lime Kiln Valley. (a) Name. The name of the viticultural area described in this section is “Lime Kiln Valley...

Oxygenation as a driver of the Great Ordovician Biodiversification Event

Science.gov (United States)

Edwards, Cole T.; Saltzman, Matthew R.; Royer, Dana L.; Fike, David A.

2017-12-01

The largest radiation of Phanerozoic marine animal life quadrupled genus-level diversity towards the end of the Ordovician Period about 450 million years ago. A leading hypothesis for this Great Ordovician Biodiversification Event is that cooling of the Ordovician climate lowered sea surface temperatures into the thermal tolerance window of many animal groups, such as corals. A complementary role for oxygenation of subsurface environments has been inferred based on the increasing abundance of skeletal carbonate, but direct constraints on atmospheric O2 levels remain elusive. Here, we use high-resolution paired bulk carbonate and organic carbon isotope records to determine the changes in isotopic fractionation between these phases throughout the Ordovician radiation. These results can be used to reconstruct atmospheric O2 levels based on the O2-dependent fractionation of carbon isotopes by photosynthesis. We find a strong temporal link between the Great Ordovician Biodiversification Event and rising O2 concentrations, a pattern that is corroborated by O2 models that use traditional carbon-sulfur mass balance. We conclude that that oxygen levels probably played an important role in regulating early Palaeozoic biodiversity levels, even after the Cambrian Explosion.

Electrical valley filtering in transition metal dichalcogenides

Science.gov (United States)

Hsieh, Tzu-Chi; Chou, Mei-Yin; Wu, Yu-Shu

2018-03-01

This work investigates the feasibility of electrical valley filtering for holes in transition metal dichalcogenides. We look specifically into the scheme that utilizes a potential barrier to produce valley-dependent tunneling rates, and perform the study with both a k .p -based analytic method and a recursive Green's function-based numerical method. The study yields the transmission coefficient as a function of incident energy and transverse wave vector, for holes going through lateral quantum barriers oriented in either armchair or zigzag directions, in both homogeneous and heterogeneous systems. The main findings are the following: (1) The tunneling current valley polarization increases with increasing barrier width or height; (2) both the valley-orbit interaction and band structure warping contribute to valley-dependent tunneling, with the former contribution being manifest in structures with asymmetric potential barriers, and the latter being orientation dependent and reaching maximum for transmission in the armchair direction; and (3) for transmission ˜0.1 , a tunneling current valley polarization of the order of 10 % can be achieved.

Water resources of Parowan Valley, Iron County, Utah

Science.gov (United States)

Marston, Thomas M.

2017-08-29

Parowan Valley, in Iron County, Utah, covers about 160 square miles west of the Red Cliffs and includes the towns of Parowan, Paragonah, and Summit. The valley is a structural depression formed by northwest-trending faults and is, essentially, a closed surface-water basin although a small part of the valley at the southwestern end drains into the adjacent Cedar Valley. Groundwater occurs in and has been developed mainly from the unconsolidated basin-fill aquifer. Long-term downward trends in groundwater levels have been documented by the U.S. Geological Survey (USGS) since the mid-1950s. The water resources of Parowan Valley were assessed during 2012 to 2014 with an emphasis on refining the understanding of the groundwater and surface-water systems and updating the groundwater budget.Surface-water discharge of five perennial mountain streams that enter Parowan Valley was measured from 2013 to 2014. The total annual surface-water discharge of the five streams during 2013 to 2014 was about 18,000 acre-feet (acre-ft) compared to the average annual streamflow of about 22,000 acre-ft from USGS streamgages operated on the three largest of these streams from the 1940s to the 1980s. The largest stream, Parowan Creek, contributes more than 50 percent of the annual surface-water discharge to the valley, with smaller amounts contributed by Red, Summit, Little, and Cottonwood Creeks.Average annual recharge to the Parowan Valley groundwater system was estimated to be about 25,000 acre-ft from 1994 to 2013. Nearly all recharge occurs as direct infiltration of snowmelt and rainfall on the Markagunt Plateau east of the valley. Smaller amounts of recharge occur as infiltration of streamflow and unconsumed irrigation water near the east side of the valley on alluvial fans associated with mountain streams at the foot of the Red Cliffs. Subsurface flow from the mountain block to the east of the valley is a significant source of groundwater recharge to the basin-fill aquifer

EPA Region 1 - Valley Depth in Meters

Science.gov (United States)

Raster of the Depth in meters of EPA-delimited Valleys in Region 1.Valleys (areas that are lower than their neighbors) were extracted from a Digital Elevation Model (USGS, 30m) by finding the local average elevation, subtracting the actual elevation from the average, and selecting areas where the actual elevation was below the average. The landscape was sampled at seven scales (circles of 1, 2, 4, 7, 11, 16, and 22 km radius) to take into account the diversity of valley shapes and sizes. Areas selected in at least four scales were designated as valleys.

Preliminary hydrogeologic assessment near the boundary of the Antelope Valley and El Mirage Valley groundwater basins, California

Science.gov (United States)

Stamos, Christina L.; Christensen, Allen H.; Langenheim, Victoria

2017-07-19

The increasing demands on groundwater for water supply in desert areas in California and the western United States have resulted in the need to better understand groundwater sources, availability, and sustainability. This is true for a 650-square-mile area that encompasses the Antelope Valley, El Mirage Valley, and Upper Mojave River Valley groundwater basins, about 50 miles northeast of Los Angeles, California, in the western part of the Mojave Desert. These basins have been adjudicated to ensure that groundwater rights are allocated according to legal judgments. In an effort to assess if the boundary between the Antelope Valley and El Mirage Valley groundwater basins could be better defined, the U.S. Geological Survey began a cooperative study in 2014 with the Mojave Water Agency to better understand the hydrogeology in the area and investigate potential controls on groundwater flow and availability, including basement topography.Recharge is sporadic and primarily from small ephemeral washes and streams that originate in the San Gabriel Mountains to the south; estimates range from about 400 to 1,940 acre-feet per year. Lateral underflow from adjacent basins has been considered minor in previous studies; underflow from the Antelope Valley to the El Mirage Valley groundwater basin has been estimated to be between 100 and 1,900 acre-feet per year. Groundwater discharge is primarily from pumping, mostly by municipal supply wells. Between October 2013 and September 2014, the municipal pumpage in the Antelope Valley and El Mirage Valley groundwater basins was reported to be about 800 and 2,080 acre-feet, respectively.This study was motivated by the results from a previously completed regional gravity study, which suggested a northeast-trending subsurface basement ridge and saddle approximately 3.5 miles west of the boundary between the Antelope Valley and El Mirage Valley groundwater basins that might influence groundwater flow. To better define potential basement

Optically initialized robust valley-polarized holes in monolayer WSe2

KAUST Repository

Hsu, Wei-Ting

2015-11-25

A robust valley polarization is a key prerequisite for exploiting valley pseudospin to carry information in next-generation electronics and optoelectronics. Although monolayer transition metal dichalcogenides with inherent spin–valley coupling offer a unique platform to develop such valleytronic devices, the anticipated long-lived valley pseudospin has not been observed yet. Here we demonstrate that robust valley-polarized holes in monolayer WSe2 can be initialized by optical pumping. Using time-resolved Kerr rotation spectroscopy, we observe a long-lived valley polarization for positive trion with a lifetime approaching 1 ns at low temperatures, which is much longer than the trion recombination lifetime (~10–20 ps). The long-lived valley polarization arises from the transfer of valley pseudospin from photocarriers to resident holes in a specific valley. The optically initialized valley pseudospin of holes remains robust even at room temperature, which opens up the possibility to realize room-temperature valleytronics based on transition metal dichalcogenides.

Carbonate microbialites and hardgrounds from Manito Lake, an alkaline, hypersaline lake in the northern Great Plains of Canada

Science.gov (United States)

Last, Fawn M.; Last, William M.; Halden, Norman M.

2010-03-01

Manito Lake is a large, perennial, Na-SO 4 dominated saline to hypersaline lake located in the northern Great Plains of western Canada. Significant water level decrease over the past several decades has led to reduction in volume and surface area, as well as an increase in salinity. The salinity has increased from 10 ppt to about 50 ppt TDS. This decrease in water level has exposed large areas of nearshore microbialites. These organogenic structures range in size from several cm to over a meter and often form large bioherms several meters high. They have various external morphologies, vary in mineralogical composition, and show a variety of internal fabrics from finely laminated to massive. In addition to microbiolities and bioherms, the littoral zone of Manito Lake contains a variety of carbonate hardgrounds, pavements, and cemented clastic sediments. Dolomite and aragonite are the most common minerals found in these shoreline structures, however, calcite after ikaite, monohydrocalcite, magnesian calcite, and hydromagnesite are also present. The dolomite is nonstoichiometric and calcium-rich; the magnesian calcite has about 17 mol% MgCO 3. AMS radiocarbon dating of paired organic matter and endogenic carbonate material confirms little or no reservoir affect. Although there is abundant evidence for modern carbonate mineral precipitation and microbialite formation, most of the larger microbialites formed between about 2300 and 1000 cal BP, whereas the hardgrounds, cements, and laminated crusts formed about 1000-500 cal BP.

Valley-orbit hybrid states in Si quantum dots

Science.gov (United States)

Gamble, John; Friesen, Mark; Coppersmith, S. N.

2013-03-01

The conduction band for electrons in layered Si nanostructures oriented along (001) has two low-lying valleys. Most theoretical treatments assume that these valleys are decoupled from the long-wavelength physics of electron confinement. In this work, we show that even a minimal amount of disorder (a single atomic step at the quantum well interface) is sufficient to mix valley states and electron orbitals, causing a significant distortion of the long-wavelength electron envelope. For physically realistic electric fields and dot sizes, this valley-orbit coupling impacts all electronic states in Si quantum dots, implying that one must always consider valley-orbit hybrid states, rather than distinct valley and orbital degrees of freedom. We discuss the ramifications of our results on silicon quantum dot qubits. This work was supported in part by ARO (W911NF-08-1-0482) and NSF (DMR-0805045).

Carbonate deposition on tail feathers of ruddy ducks using evaporation ponds

Science.gov (United States)

Euliss, N.H.; Jarvis, R.L.; Gilmer, D.S.

1989-01-01

Substantial carbonate deposits were observed on rectrices of Ruddy Ducks (Oxyura jamaicensis) collected during 1982-1984 on evaporation ponds in the San Joaquin Valley, California. Carbonate deposits were composed of about 75% aragonite and 25% calcite, both polymorphous forms of CaCO3. Significantly more carbonate deposits were observed on Ruddy Ducks as length of exposure to agricultural drain water increased, during the 1983-1984 field season when salt concentrations in the ponds were higher, and in certain evaporation-pond systems.

Geohydrology of the Unconsolidated Valley-Fill Aquifer in the Meads Creek Valley, Schuyler and Steuben Counties, New York

Science.gov (United States)

Miller, Todd S.; Bugliosi, Edward F.; Reddy, James E.

2008-01-01

The Meads Creek valley encompasses 70 square miles of predominantly forested uplands in the upper Susquehanna River drainage basin. The valley, which was listed as a Priority Waterbody by the New York State Department of Environmental Conservation in 2004, is prone to periodic flooding, mostly in its downstream end, where development is occurring most rapidly. Hydraulic characteristics of the unconsolidated valley-fill aquifer were evaluated, and seepage rates in losing and gaining tributaries were calculated or estimated, in an effort to delineate the aquifer geometry and identify the factors that contribute to flooding. Results indicated that (1) Meads Creek gained about 61 cubic feet of flow per second (about 6.0 cubic feet per second per mile of stream channel) from ground-water discharge and inflow from tributaries in its 10.2-mile reach between the northernmost and southernmost measurement sites; (2) major tributaries in the northern part of the valley are not significant sources of recharge to the aquifer; and (3) major tributaries in the central and southern part of the valley provide recharge to the aquifer. The ground-water portion of streamflow in Meads Creek (excluding tributary inflow) was 11.3 cubic feet per second (ft3/s) in the central part of the valley and 17.2 ft3/s in the southern part - a total of 28.5 ft3/s. Ground-water levels were measured in 29 wells finished in unconfined deposits for construction of a potentiometric-surface map to depict directions of ground-water flow within the valley. In general, ground water flows from the edges of the valley toward Meads Creek and ultimately discharges to it. The horizontal hydraulic gradient for the entire 12-mile-long aquifer averages about 30 feet per mile, whereas the gradient in the southern fourth of the valley averages about half that - about 17 feet per mile. A water budget for the aquifer indicated that 28 percent of recharge was derived from precipitation that falls on the aquifer, 32

Land use in the northern Coachella Valley

Science.gov (United States)

Bale, J. B.; Bowden, L. W.

1973-01-01

Satellite imagery has proved to have great utility for monitoring land use change and as a data source for regional planning. In California, open space desert resources are under severe pressure to serve as a source for recreational gratification to individuals living in the heavily populated southern coastal plain. Concern for these sensitive arid environments has been expressed by both federal and state agencies. The northern half of the Coachella Valley has historically served as a focal point for weekend recreational activity and second homes. Since demand in this area has remained high, land use change from rural to urban residential has been occurring continuously since 1968. This area of rapid change is an ideal site to illustrate the utility of satellite imagery as a data source for planning information, and has served as the areal focus of this investigation.

California's Central Valley Groundwater Study: A Powerful New Tool to Assess Water Resources in California's Central Valley

Science.gov (United States)

Faunt, Claudia C.; Hanson, Randall T.; Belitz, Kenneth; Rogers, Laurel

2009-01-01

Competition for water resources is growing throughout California, particularly in the Central Valley. Since 1980, the Central Valley's population has nearly doubled to 3.8 million people. It is expected to increase to 6 million by 2020. Statewide population growth, anticipated reductions in Colorado River water deliveries, drought, and the ecological crisis in the Sacramento-San Joaquin Delta have created an intense demand for water. Tools and information can be used to help manage the Central Valley aquifer system, an important State and national resource.

Valley and spin thermoelectric transport in ferromagnetic silicene junctions

International Nuclear Information System (INIS)

Ping Niu, Zhi; Dong, Shihao

2014-01-01

We have investigated the valley and spin resolved thermoelectric transport in a normal/ferromagnetic/normal silicene junction. Due to the coupling between the valley and spin degrees of freedom, thermally induced pure valley and spin currents can be demonstrated. The magnitude and sign of these currents can be manipulated by adjusting the ferromagnetic exchange field and local external electric field, thus the currents are controllable. We also find fully valley and/or spin polarized currents. Similar to the currents, owing to the band structure symmetry, tunable pure spin and/or valley thermopowers with zero charge counterpart are generated. The results obtained here suggest a feasible way of generating a pure valley (spin) current and thermopower in silicene

InSAR to support sustainable urbanization over compacting aquifers: The case of Toluca Valley, Mexico

Science.gov (United States)

Castellazzi, Pascal; Garfias, Jaime; Martel, Richard; Brouard, Charles; Rivera, Alfonso

2017-12-01

This paper illustrates how InSAR alone can be used to delineate potential ground fractures related to aquifer system compaction. An InSAR-derived ground fracturing map of the Toluca Valley, Mexico, is produced and validated through a field campaign. The results are of great interest to support sustainable urbanization and show that InSAR processing of open-access Synthetic Aperture Radar (SAR) data from the Sentinel-1 satellites can lead to reliable and cost-effective products directly usable by cities to help decision-making. The Toluca Valley Aquifer (TVA) sustains the water needs of two million inhabitants living within the valley, a growing industry, an intensively irrigated agricultural area, and 38% of the water needs of the megalopolis of Mexico City, located 40 km east of the valley. Ensuring water sustainability, infrastructure integrity, along with supporting the important economic and demographic growth of the region, is a major challenge for water managers and urban developers. This paper presents a long-term analysis of ground fracturing by interpreting 13 years of InSAR-derived ground displacement measurements. Small Baseline Subset (SBAS) and Persistent Scatterer Interferometry (PSI) techniques are applied over three SAR datasets totalling 93 acquisitions from Envisat, Radarsat-2, and Sentinel-1A satellites and covering the period from 2003 to 2016. From 2003 to 2016, groundwater level declines of up to 1.6 m/yr, land subsidence up to 77 mm/yr, and major infrastructure damages are observed. Groundwater level data show highly variable seasonal responses according to their connectivity to recharge areas. However, the trend of groundwater levels consistently range from -0.5 to -1.5 m/yr regardless of the well location and depth. By analysing the horizontal gradients of vertical land subsidence, we provide a potential ground fracture map to assist in future urban development planning in the Toluca Valley.

Wintertime particulate pollution episodes in an urban valley of the Western US: a case study

Directory of Open Access Journals (Sweden)

L.-W. A. Chen

2012-11-01

Full Text Available This study investigates the causes of elevated PM_2.5 episodes and potential exceedences of the US National Ambient Air Quality Standards (NAAQS in Truckee Meadows, Nevada, an urban valley of the Western US, during winter 2009/2010, an unusually cold and snowy winter. Continuous PM_2.5 mass and time-integrated chemical speciation data were acquired from a central valley monitoring site, along with meteorological measurements from nearby sites. All nine days with PM_2.5 > 35 μg m⁻³ showed 24-h average temperature inversion of 1.5–4.5 °C and snow cover of 8–18 cm. Stagnant atmospheric conditions limited wind ventilation while highly reflective snow cover reduced daytime surface heating creating persistent inversion. Elevated ammonium nitrate (NH₄NO₃ and water associated with it are found to be main reasons for the PM_2.5 exceedances. An effective-variance chemical mass balance (EV-CMB receptor model using locally-derived geological profiles and inorganic/organic markers confirmed secondary NH₄NO₃ (27–37%, residential wood combustion (RWC; 11–51%, and diesel engine exhaust (7–22% as the dominant PM_2.5 contributors. Paved road dust and de-icing materials were minor, but detectable contributors. RWC is a more important source than diesel for organic carbon (OC, but vice versa for elemental carbon (EC. A majority of secondary NH₄NO₃ is also attributed to RWC and diesel engines (including snow removal equipment through oxides of nitrogen (NO_x emissions from these sources. Findings from this study may apply to similar situations experienced by other urban valleys.

Zeolite Formation and Weathering Processes in Dry Valleys of Antartica: Martian Analogs

Science.gov (United States)

Gibson, E. K., Jr.; Wentworth, S. J.; McKay, D. S.; Socki, R. A.

2004-01-01

Terrestrial weathering processes in cold-desert climates such as the Dry Valleys of Antarctica may provide an excellent analog to chemical weathering and diagenesis of soils on Mars. Detailed studies of soil development and the chemical and mineralogical alterations occurring within soil columns in Wright Valley, Antarctica show incredible complexity in the upper meter of soil. Previous workers noted the ice-free Dry Valleys are the best terrestrial approximations to contemporary Mars. Images returned from the Pathfinder and Spirit landers show similarities to surfaces observed within the Dry Valleys. Similarities to Mars that exist in these valleys are: mean temperatures always below freezing (-20 C), no rainfall, sparse snowfall-rapidly removed by sublimation, desiccating winds, diurnal freeze-thaw cycles (even during daylight hours), low humidity, oxidative environment, relatively high solar radiation and low magnetic fields . The Dry Valley soils contain irregular distributions and low abundances of soil microorganisms that are somewhat unusual on Earth. Physical processes-such as sand abrasion-are dominant mechanisms of rock weathering in Antarctica. However, chemical weathering is also an important process even in such extreme climates. For example, ionic migration occurs even in frozen soils along liquid films on individual soil particles. It has also been shown that water with liquid-like properties is present in soils at temperatures on the order of approx.-80 C and it has been observed that the percentage of oxidized iron increases with increasing soil age and enrichments in oxidized iron occurs toward the surface. The presence of evaporates is evident and appear similar to "evaporite sites" within the Pathfinder and Spirit sites. Evaporites indicate ionic migration and chemical activity even in the permanently frozen zone. The presence of evaporates indicates that chemical weathering of rocks and possibly soils has been active. Authogenic zeolites have

Engineering assessment of inactive uranium mill tailings: Monument Valley Site, Monument Valley, Arizona

Energy Technology Data Exchange (ETDEWEB)

1981-10-01

Ford, Bacon and Davis Utah Inc. has reevalated the Monument Valley site in order to revise the March 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Monument Valley, Arizona. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposure of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 1.1 million tons of tailings at the Monument Valley site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The four alternative actions presented in this engineering assessment range from millsite decontamination with the addition of 3 m of stabilization cover material (Option I), to removal of the tailings to remote disposal sites and decontamination of the tailings site (Options II through IV). Cost estimates for the four options range from about $6,600,000 for stabilization in-place, to about $15,900,000 for disposal at a distance of about 15 mi. Three principal alternatives for reprocessing the Monument Valley tailings were examined: heap leaching; Treatment at an existing mill; and reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovery is economically unattractive.

Engineering assessment of inactive uranium mill tailings: Monument Valley Site, Monument Valley, Arizona

International Nuclear Information System (INIS)

1981-10-01

Ford, Bacon and Davis Utah Inc. has reevalated the Monument Valley site in order to revise the March 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Monument Valley, Arizona. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposure of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 1.1 million tons of tailings at the Monument Valley site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The four alternative actions presented in this engineering assessment range from millsite decontamination with the addition of 3 m of stabilization cover material (Option I), to removal of the tailings to remote disposal sites and decontamination of the tailings site (Options II through IV). Cost estimates for the four options range from about $6,600,000 for stabilization in-place, to about $15,900,000 for disposal at a distance of about 15 mi. Three principal alternatives for reprocessing the Monument Valley tailings were examined: heap leaching; Treatment at an existing mill; and reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovery is economically unattractive

Sustainable agricultural development in inland valleys

NARCIS (Netherlands)

Zwart, S.J.

2018-01-01

The inland valley in Africa are common landscapes that have favorable conditions for agricultural production. Compared to the surrounding uplands they are characterized by a relatively high and secure water availability and high soil fertility levels. Inland valleys thus have a high agricultural

Carbon Nanomaterials as Antibacterial Colloids

Directory of Open Access Journals (Sweden)

Michael Maas

2016-07-01

Full Text Available Carbon nanomaterials like graphene, carbon nanotubes, fullerenes and the various forms of diamond have attracted great attention for their vast potential regarding applications in electrical engineering and as biomaterials. The study of the antibacterial properties of carbon nanomaterials provides fundamental information on the possible toxicity and environmental impact of these materials. Furthermore, as a result of the increasing prevalence of resistant bacteria strains, the development of novel antibacterial materials is of great importance. This article reviews current research efforts on characterizing the antibacterial activity of carbon nanomaterials from the perspective of colloid and interface science. Building on these fundamental findings, recent functionalization strategies for enhancing the antibacterial effect of carbon nanomaterials are described. The review concludes with a comprehensive outlook that summarizes the most important discoveries and trends regarding antibacterial carbon nanomaterials.

Valley-polarized quantum transport generated by gauge fields in graphene

Science.gov (United States)

Settnes, Mikkel; Garcia, Jose H.; Roche, Stephan

2017-09-01

We report on the possibility to simultaneously generate in graphene a bulk valley-polarized dissipative transport and a quantum valley Hall effect by combining strain-induced gauge fields and real magnetic fields. Such unique phenomenon results from a ‘resonance/anti-resonance’ effect driven by the superposition/cancellation of superimposed gauge fields which differently affect time reversal symmetry. The onset of a valley-polarized Hall current concomitant to a dissipative valley-polarized current flow in the opposite valley is revealed by a {{e}2}/h Hall conductivity plateau. We employ efficient linear scaling Kubo transport methods combined with a valley projection scheme to access valley-dependent conductivities and show that the results are robust against disorder.

Groundwater availability of the Central Valley Aquifer, California

Science.gov (United States)

Faunt, Claudia C.

2009-01-01

California's Central Valley covers about 20,000 square miles and is one of the most productive agricultural regions in the world. More than 250 different crops are grown in the Central Valley with an estimated value of $17 billion per year. This irrigated agriculture relies heavily on surface-water diversions and groundwater pumpage. Approximately one-sixth of the Nation's irrigated land is in the Central Valley, and about one-fifth of the Nation's groundwater demand is supplied from its aquifers. The Central Valley also is rapidly becoming an important area for California's expanding urban population. Since 1980, the population of the Central Valley has nearly doubled from 2 million to 3.8 million people. The Census Bureau projects that the Central Valley's population will increase to 6 million people by 2020. This surge in population has increased the competition for water resources within the Central Valley and statewide, which likely will be exacerbated by anticipated reductions in deliveries of Colorado River water to southern California. In response to this competition for water, a number of water-related issues have gained prominence: conservation of agricultural land, conjunctive use, artificial recharge, hydrologic implications of land-use change, and effects of climate variability. To provide information to stakeholders addressing these issues, the USGS Groundwater Resources Program made a detailed assessment of groundwater availability of the Central Valley aquifer system, that includes: (1) the present status of groundwater resources; (2) how these resources have changed over time; and (3) tools to assess system responses to stresses from future human uses and climate variability and change. This effort builds on previous investigations, such as the USGS Central Valley Regional Aquifer System and Analysis (CV-RASA) project and several other groundwater studies in the Valley completed by Federal, State and local agencies at differing scales. The

An example of Alaknanda valley, Garhwal Himalaya, India

Indian Academy of Sciences (India)

2014) have been best explained by the geometry .... flows through narrow valley confined by the steep valley slopes. ... valley (figure 3b) which opens up around Srina- ... Method. 4.1 Drainage basin and stream network. Digital Elevation Model (DEM) helps in extracting ... was processed to fill the pits or sinks, and to obtain.

Last glacial-Holocene temperatures and hydrology of the Sea of Galilee and Hula Valley from clumped isotopes in Melanopsis shells

Science.gov (United States)

Zaarur, Shikma; Affek, Hagit P.; Stein, Mordechai

2016-04-01

The carbonate clumped isotope (Δ47) thermometer was applied to fresh water snails (Melanopsis spp.) grown in the waters of the Sea of Galilee and Hula Valley, in the north of Israel. Modern shells, grown at known temperatures agree with the Δ47-T calibration of Zaarur et al. (2013). Fossil Melanopsis shells from 2 locations, Gesher Bnot Ya'aqov (at the southern tip of the Hula Valley) and the Sea of Galilee provide a temperature record for the region during the time interval of the past 20 kyrs. Glacial temperatures are ∼5 °C cooler than mid-Holocene and ∼3 °C cooler than modern, similar to other records in the region. These Δ47-derived temperatures are combined with δ18O of the shell carbonate to calculate the oxygen isotopic composition of the habitat waters. Contrary to global trends and other regional records, reconstructed δ18Owater values increase from the late glacial through the Holocene. This reversed signal reflects a decrease in the relative contribution of snowmelt to the watershed post-LGM and a transition to a more rain dominated inflow. A fairly constant difference in δ18Owater values between the Hula Valley and Sea of Galilee waters, suggests that the hydrological relationship of the two water bodies had remained constant, with the temperature changes playing only a minor role in the extent of evaporation of the Sea of Galilee relative to the Hula.

The cadastre of waste heat in the Upper Rhine Valley

International Nuclear Information System (INIS)

Bartholomaei, G.; Kinzelbach, W.

1980-04-01

The cadastre of waste heat provides the distribution in space and time of anthropogeneous waste heat emissions on a 2 x 2 km 2 grid. In the case of the Upper Rhine Valley it serves as a basis for the numerical evaluations of climatic changes caused by man. Such a cadastre also allows to analyse the distribution of pollutant emissions and the heat or energy supply, respectively, of the region. In a close approximation the distribution of waste heat is equal to the distribution of energy consumption. As there are generally difficulties in obtaining data about the consumption of the types of energy on the grid level, methods were developed which allow to determine the local energy consumption by using the relevant structural data. The methods used for the Federal Republic of Germany and neighbouring countries and the results for the Upper Rhine Valley, obtained by these methods, are presented. The cadastre of waste heat is based on data of the year 1973 which was a time of great energy consumption. Only in 1978 this energy consumption was exceeded. To be able to estimate the change in the influence of the anthropogeneous waste heat during the next 20 years, the cadastre was extrapolated until the year 2000. (orig.) [de

The development and adaption of early agriculture in Huanghe River Valley, China

Science.gov (United States)

Li, X.

2017-12-01

The expanding and developing of agriculture are the basic of population growth, the expansions of material cultures and civilization. The Huanghe River valley, as the origin center of millet agriculture, lies between the heartlands of wheat and rice, which gestates the flourishing Neolithic culture based on agriculture. Recent work using botanical remains has greatly expanded the knowledge concerning early agriculture. Here, we report the new progress on the development and adaption of early agriculture in Huanghe River valley and the surrounding areas. Based on the analysis of phytolith from 13 sites in middle reaches of Huanghe River and the survey of crop seeds from 5 sites in Guanzhong Basin, the rice have been cultivated around 7600 cal BP in semi-humid regions dominated by rain-fed agriculture. The mixed agriculture of common millet, foxtail millet, and rice continued to exist between 7600-3500 BP. In semi-arid region of Huanghe River valley, the agriculture was dominated by the production of common and foxtail millet and 3 major changes have taken place around 6500 BP, 5500 BP, and 4000 BP during Neolithic. The cultivating ratio of common and foxtail millet was adjusted by farmer for adapting the climate changes during Holocene. Approximately 5000 yr BP, the rain-fed agriculture continues to break geographical boundaries to expand to west and southwest from Huanghe River valley. Millet agriculture appeared in southern Ganshu and north eastern Tibetan Plateau. The common and foxtail millet spread to the arid-area of Hexi corridor, a major crossroad of the famous Silk Road, around 4500 yr BP. Wheat was added as a new crop to the existing millet based agricultural systems around 4100-4000 cal yr BP in Hexi corridor. Between 3800 and 3400 cal yr BP, the proportion of wheat and barley in agriculture was up to 90%,which have replaced the local millet and become the main crops. And now, some new evidences of wheat agriculture from NW Xijiang have been obtained and

Intra- and inter-shell Kondo effects in carbon nanotube quantum dots

Science.gov (United States)

Krychowski, Damian; Lipiński, Stanisław

2018-01-01

The linear response transport properties of carbon nanotube quantum dot in the strongly correlated regime are discussed. The finite-U mean field slave boson approach is used to study many-body effects. Magnetic field can rebuilt Kondo correlations, which are destroyed by the effect of spin-orbit interaction or valley mixing. Apart from the field induced revivals of SU(2) Kondo effects of different types: spin, valley or spin-valley, also more exotic phenomena appear, such as SU(3) Kondo effect. Threefold degeneracy occurs due to the effective intervalley exchange induced by short-range part of Coulomb interaction or due to the intershell mixing. In narrow gap nanotubes the full spin-orbital degeneracy might be recovered in the absence of magnetic field opening the condition for a formation of SU(4) Kondo resonance.

Do invasive quagga mussels alter CO2 dynamics in the Laurentian Great Lakes?

Science.gov (United States)

Lin, Peng; Guo, Laodong

2016-12-01

The Laurentian Great Lakes have experienced unprecedented ecological and environmental changes, especially after the introduction of invasive quagga mussel (Dreissena rostriformis bugensis). While impacts on ecological functions have been widely recognized, the response of carbon dynamics to invasive species remains largely unknown. We report new CO2 data showing significant increases in pCO2 (up to 800 μatm in Lake Michigan) and CO2 emission fluxes in most of the Great Lakes compared to those prior to or during the early stage of the colonization of invasive quagga mussels. The increased CO2 supersaturation is most prominent in Lakes Huron and Michigan, followed by Lakes Ontario and Erie, but no evident change was observed in Lake Superior. This trend mirrors the infestation extent of invasive quagga mussels in the Great Lakes and is consistent with the decline in primary production and increase in water clarity observed pre- and post-Dreissena introduction, revealing a close linkage between invasive species and carbon dynamics. The Great Lakes have become a significant CO2 source to the atmosphere, emitting >7.7 ± 1.0 Tg-C annually, which is higher than the organic carbon burial rate in global inland-seas and attesting to the significant role of the Laurentian Great Lakes in regional/global CO2 budget and cycling.

A disconnect between O horizon and mineral soil carbon - Implications for soil C sequestration

Science.gov (United States)

Garten, Charles T., Jr.

2009-03-01

Changing inputs of carbon to soil is one means of potentially increasing carbon sequestration in soils for the purpose of mitigating projected increases in atmospheric CO 2 concentrations. The effect of manipulations of aboveground carbon input on soil carbon storage was tested in a temperate, deciduous forest in east Tennessee, USA. A 4.5-year experiment included exclusion of aboveground litterfall and supplemental litter additions (three times ambient) in an upland and a valley that differed in soil nitrogen availability. The estimated decomposition rate of the carbon stock in the O horizon was greater in the valley than in the upland due to higher litter quality (i.e., lower C/N ratios). Short-term litter exclusion or addition had no effect on carbon stock in the mineral soil, measured to a depth of 30 cm, or the partitioning of carbon in the mineral soil between particulate- and mineral-associated organic matter. A two-compartment model was used to interpret results from the field experiments. Field data and a sensitivity analysis of the model were consistent with little carbon transfer between the O horizon and the mineral soil. Increasing aboveground carbon input does not appear to be an effective means of promoting carbon sequestration in forest soil at the location of the present study because a disconnect exists in carbon dynamics between O horizon and mineral soil. Factors that directly increase inputs to belowground soil carbon, via roots, or reduce decomposition rates of organic matter are more likely to benefit efforts to increase carbon sequestration in forests where carbon dynamics in the O horizon are uncoupled from the mineral soil.

California's restless giant: the Long Valley Caldera

Science.gov (United States)

Hill, David P.; Bailey, Roy A.; Hendley, James W.; Stauffer, Peter H.; Marcaida, Mae

2014-01-01

Scientists have monitored geologic unrest in the Long Valley, California, area since 1980. In that year, following a swarm of strong earthquakes, they discovered that the central part of the Long Valley Caldera had begun actively rising. Unrest in the area persists today. The U.S. Geological Survey (USGS) continues to provide the public and civil authorities with current information on the volcanic hazard at Long Valley and is prepared to give timely warnings of any impending eruption.

Petrography and geochemistry of Oligocene bituminous coal from the Jiu Valley, Petrosani basin (southern Carpathian Mountains), Romania

Energy Technology Data Exchange (ETDEWEB)

Belkin, Harvey E.; Tewalt, Susan J. [U.S. Geological Survey, 956 National Center, Reston, VA 20192 (United States); Hower, James C. [University of Kentucky Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511 (United States); Stucker, J.D. [University of Kentucky Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511 (United States); University of Kentucky Department of Earth and Environmental Sciences, Lexington, KY 40506 (United States); O' Keefe, Jennifer M.K. [Morehead State University, Morehead, KY, 40351 (United States); Tatu, Calin A. [University of Medicine and Pharmacy, Department of Immunology, Clinical Laboratory No. 1, Pta. E. Murgu No. 2, RO-1900 Timisoara (Romania); Buia, Grigore [University of Petrosani, Department of Geology, University St. 20, RO-2675 Petrosani (Romania)

2010-05-01

Belt samples of Oligocene (Chattian) bituminous coal from 10 underground mines located in the Jiu Valley, Hunedoara County, Petrosani basin, Romania, have been examined and analyzed for proximate and ultimate analysis, major-, minor- and trace-element chemistry, organic petrography, and vitrinite reflectance. The mineral chemistry and mode of occurrence of trace elements also have been investigated using SEM and electron microprobe techniques. Twenty coal beds occur in the Jiu Valley and most of the samples are from bed no. 3, the most productive bed of the Dilja-Uricani Formation of Oligocene age. The Petrosani basin, oriented SW-NE, is 48-km long, 10-km wide at the eastern part and 2-km wide at the western part. The coal mines are distributed along the center of the valley generally following the Jiu de Vest River. Reflectance measurements indicate that the rank of the coals ranges from high-volatile B to high-volatile A bituminous. Overall, rank decreases from the southwest to the northeast. In bed no. 3, R{sub max} varies from 0.75% in the northeast to 0.93% in the southwest. Although, most Oligocene coals in Romania and adjacent countries are lignite in rank, the Jiu Valley bituminous coals have been affected by regional metamorphism and attending hydrothermal fluids related to the Alpine orogenic event. The coals are all dominated by vitrinite; resinite and funginite are important minor macerals in most of the coals. Pyrite and carbonate generally dominate the mineral assemblages with carbonate more abundant in the northwest. Siderite occurs as nodules and masses within the macerals (generally vitrinite). Dolomite and calcite occur as fracture fillings, plant-cell fillings, and in other authigenic forms. Late-stage fracture fillings are siderite, dolomite, calcite, and ankerite. In one instance, two populations of siderite ({proportional_to} 35 and {proportional_to} 45 wt.% FeO) plus ankerite fill a large fracture. Late-stage pyrite framboid alteration is Ni

Valley Fever

Science.gov (United States)

... valley fever. These fungi are commonly found in soil in specific regions. The fungi's spores can be stirred into the air by ... species have a complex life cycle. In the soil, they grow as a mold with long filaments that break off into airborne ...

The Nile valley of Egypt: A major active graben that magnifies seismic waves

International Nuclear Information System (INIS)

EI-Sayed, A.; Vaccari, F.; Panza, G.F.

2002-08-01

The Nile valley and the Nile delta are part of the active rift that is probably connected with the Red Sea tectonism. This zone is characterized by small to moderate size earthquakes that have caused extremely severe damage to recent and historical constructions. The most vulnerable area along the Nile valley is the one of Cairo-Faiyoum. Small local and large distant earthquakes could be a source of huge socio-economic damage in this area. The loose soft alluvial sediments of the Nile Canyon are the main factors behind this potential damage because they may greatly amplify the ground motion, as demonstrated by strong ground motion modelling. The largest amplification is generally concentrated along the edges of the graben and occurs at frequencies between 1 Hz and 2 Hz. This may explain the huge damage caused by distant earthquakes during recent and historical times. The distribution of intensity values during the events of 1926 and 1992 is well correlated with the modelled spatial distribution of the spectral amplification. (author)

Nematic and Valley Ordering in Anisotropic Quantum Hall Systems

Science.gov (United States)

Parameswaran, S. A.; Abanin, D. A.; Kivelson, S. A.; Sondhi, S. L.

2010-03-01

We consider a multi-valley two dimensional electron system in the quantum Hall effect (QHE) regime. We focus on QHE states that arise due to spontaneous breaking of the valley symmetry by the Coulomb interactions. We show that the anisotropy of the Fermi surface in each valley, which is generally present in such systems, favors states where all the electrons reside in one of the valleys. In a clean system, the valley ordering occurs via a finite temperature Ising-like phase transition, which, owing to the Fermi surface anisotropy, is accompanied by the onset of nematic order. In a disordered system, domains of opposite polarization are formed, and therefore long-range valley order is destroyed, however, the resulting state is still compressible. We discuss the transport properties in ordered and disordered regimes, and point out the possible relation of our results to recent experiments in AlAs [1]. [1] Y. P. Shkolnikov, S. Misra, N. C. Bishop, E. P. De Poortere, and M. Shayegan, Observation of Quantum Hall ``Valley Skyrmions", Phys. Rev. Lett. 95, 068809 (2005)[2] D.A. Abanin, S.A. Parameswaran, S.A. Kivelson and S.L. Sondhi, Nematic and Valley Ordering in Anisotropic Quantum Hall Systems, to be published.

[Ethnic conflicts and environmental degradation in Central Asia. The Ferghana valley and northern Kazakhstan].

Science.gov (United States)

De Cordier, B

1996-01-01

This work seeks to demonstrate that the combination of ecological degradation, demographic pressure, and ethnic heterogeneity in Central Asia constitute a serious threat to the future stability of the region. The predominantly rural Ferghana Valley and Northern Kazakhstan suffer from shortages of water and land and from unemployment that leads to extensive out-migration to cities suffering from decline in their Soviet-era industries. The problem in the Ferghana Valley began with Tsarist conquest of the valley in 1876 and the subsequent imposition of cotton cultivation, which was greatly expanded by the Soviet Union. The Ferghana Valley, despite being a natural unit, was divided between Uzbekistan, Tajikistan, and Kyrgyzstan in the 1920s and 1930s, and remains divided between the independent states. The current population of 11 million is ethnically diverse, with Uzbeks in the majority and increasing most rapidly. Immigration from the Caucasus since 1950 added to the tension. Future peace will depend on such factors as whether the neo-Communist political regime chooses to incite ethnic hostilities, the manner in which land is redistributed, and the outcome of struggles for control of the flourishing narcotics trade. The northern Kazakhstan region was designated a pioneer wheat-growing region by Soviet planners in 1954. Russian and Ukrainian migrants established between 1954 and 1956 are today the predominant population sector, but feel their privileged position threatened by nationalist policies making Kazakh the official language and giving preference in employment to Kazakhs. Resettlement of Kazakhs from Mongolia, China, and Afghanistan in the region and the high Kazakh birth rate increase tensions. Grain production initially grew rapidly, but the mediocre soil and erosion-inducing constant dry winds have caused production to stagnate or decline. Regional disputes within Kazakhstan complicate the situation. Northern Kazakhstan, with its industrial development, is

Carbon source/sink function of a subtropical, eutrophic lake determined from an overall mass balance and a gas exchange and carbon burial balance

International Nuclear Information System (INIS)

Yang Hong; Xing Yangping; Xie Ping; Ni Leyi; Rong Kewen

2008-01-01

Although studies on carbon burial in lake sediments have shown that lakes are disproportionately important carbon sinks, many studies on gaseous carbon exchange across the water-air interface have demonstrated that lakes are supersaturated with CO 2 and CH 4 causing a net release of CO 2 and CH 4 to the atmosphere. In order to more accurately estimate the net carbon source/sink function of lake ecosystems, a more comprehensive carbon budget is needed, especially for gaseous carbon exchange across the water-air interface. Using two methods, overall mass balance and gas exchange and carbon burial balance, we assessed the carbon source/sink function of Lake Donghu, a subtropical, eutrophic lake, from April 2003 to March 2004. With the overall mass balance calculations, total carbon input was 14 905 t, total carbon output was 4950 t, and net carbon budget was +9955 t, suggesting that Lake Donghu was a great carbon sink. For the gas exchange and carbon burial balance, gaseous carbon (CO 2 and CH 4 ) emission across the water-air interface totaled 752 t while carbon burial in the lake sediment was 9477 t. The ratio of carbon emission into the atmosphere to carbon burial into the sediment was only 0.08. This low ratio indicates that Lake Donghu is a great carbon sink. Results showed good agreement between the two methods with both showing Lake Donghu to be a great carbon sink. This results from the high primary production of Lake Donghu, substantive allochthonous carbon inputs and intensive anthropogenic activity. Gaseous carbon emission accounted for about 15% of the total carbon output, indicating that the total output would be underestimated without including gaseous carbon exchange. - Due to high primary production, substantive allochthonous carbon inputs and intensive anthropogenic acitivity, subtropical, eutrophic Lake Donghu is a great carbon sink

Alluvial Mountain Meadow Source-Sink Dynamics: Land-Cover Effects on Water and Fluvial Carbon Export

Science.gov (United States)

Weiss, T.; Covino, T. P.; Wohl, E.; Rhoades, C.; Fegel, T.; Clow, D. W.

2017-12-01

Fluvial networks of historically glaciated mountain landscapes alternate between confined and unconfined valley segments. In low-gradient unconfined reaches, river-connected wet meadows commonly establish, and have been recognized as important locations of long-term water, carbon, and nutrient storage. Among connected meadow floodplains, sink-source behavior shifts as a function of flow state; storing water at high flows (snowmelt) and contributing toward higher late-season baseflows. Despite these benefits, historical and contemporary land-use practices often result in the simplification of wet meadow systems, leading to reduced river-floodplain connectivity, lower water-tables and reductions in hydrologic buffering capacity. In this study, we are exploring hydrologic-carbon relationships across a gradient of valley confinement and river-floodplain connectivity (connected, n=3; disconnected, n=4) within the Colorado Rockies. Our approach includes hydrologic analysis, fluorometric assays, water chemistry, instream metabolic measures, and land-cover assessment to examine patterns between land-form, carbon quantity and quality, and stream ecosystem productivity. Between different meadow types, preliminary results suggest differences between instream productivity, carbon qualities, and hydrologic-carbon sink-source dynamics across the season. These data and analyses will provide insight into water, carbon and nutrient flux dynamics as a function of land-cover in mountain headwaters.

Thermoluminescence dating of CaCO3 nodules from buried soil of the lower Narmada Valley

International Nuclear Information System (INIS)

Nambi, K.S.V.; Hegde, K.T.M.

1982-01-01

Calcium carbonate nodules excavated at an archaeological site in Lower Narmada River Valley have been dated by the thermoluminescence technique. Tiny, sensitive TL dosimeters using natural CaF 2 as the phosphor, were employed to evaluate the natural radiation levels at the excavation site over a period of a year. The estimated TL age value is 22890 yrs B.P. with an uncertainty of about +/- 8%. The reported 14 C age of these nodules is 22452 +/- 550 years B.P

Examining Wari influence in the Las Trancas Valley, Peru using oxygen isotopes from bone carbonate

OpenAIRE

Henry, Erin-Marie Lelik

2008-01-01

The Nasca region of the Las Trancas Valley in south coastal Peru is considered to be one of several peripheral regions which were influenced by the highland Wari empire during the Middle Horizon (750-1000 AD). They are thought to have had socioeconomic and political ties with the neighboring empire. The Wari are considered to be one of the first expansive states that developed in the Andean region (Schreiber, 1992; 1999). The extent of Wari control based on archaeological evidence and diet re...

Valley photonic crystals for control of spin and topology.

Science.gov (United States)

Dong, Jian-Wen; Chen, Xiao-Dong; Zhu, Hanyu; Wang, Yuan; Zhang, Xiang

2017-03-01

Photonic crystals offer unprecedented opportunity for light manipulation and applications in optical communication and sensing. Exploration of topology in photonic crystals and metamaterials with non-zero gauge field has inspired a number of intriguing optical phenomena such as one-way transport and Weyl points. Recently, a new degree of freedom, valley, has been demonstrated in two-dimensional materials. Here, we propose a concept of valley photonic crystals with electromagnetic duality symmetry but broken inversion symmetry. We observe photonic valley Hall effect originating from valley-dependent spin-split bulk bands, even in topologically trivial photonic crystals. Valley-spin locking behaviour results in selective net spin flow inside bulk valley photonic crystals. We also show the independent control of valley and topology in a single system that has been long pursued in electronic systems, resulting in topologically-protected flat edge states. Valley photonic crystals not only offer a route towards the observation of non-trivial states, but also open the way for device applications in integrated photonics and information processing using spin-dependent transportation.

Valley Hall effect and Nernst effect in strain engineered graphene

Science.gov (United States)

Niu, Zhi Ping; Yao, Jian-ming

2018-04-01

We theoretically predict the existence of tunneling valley Hall effect and Nernst effect in the normal/strain/normal graphene junctions, where a strained graphene is sandwiched by two normal graphene electrodes. By applying an electric bias a pure transverse valley Hall current with longitudinal charge current is generated. If the system is driven by a temperature bias, a valley Nernst effect is observed, where a pure transverse valley current without charge current propagates. Furthermore, the transverse valley current can be modulated by the Fermi energy and crystallographic orientation. When the magnetic field is further considered, we obtain a fully valley-polarized current. It is expected these features may be helpful in the design of the controllable valleytronic devices.

Orbital hyperfine interaction and qubit dephasing in carbon nanotube quantum dots

Science.gov (United States)

Palyi, Andras; Csiszar, Gabor

2015-03-01

Hyperfine interaction (HF) is of key importance for the functionality of solid-state quantum information processing, as it affects qubit coherence and enables nuclear-spin quantum memories. In this work, we complete the theory of the basic hyperfine interaction mechanisms (Fermi contact, dipolar, orbital) in carbon nanotube quantum dots by providing a theoretical description of the orbital HF. We find that orbital HF induces an interaction between the nuclear spins of the nanotube lattice and the valley degree of freedom of the electrons confined in the quantum dot. We show that the resulting nuclear-spin-electron-valley interaction (i) is approximately of Ising type, (ii) is essentially local, in the sense that an effective atomic interaction strength can be defined, and (iii) has a strength that is comparable to the combined strength of Fermi contact and dipolar interactions. We argue that orbital HF provides a new decoherence mechanism for single-electron valley qubits and spin-valley qubits in a range of multi-valley materials. We explicitly evaluate the corresponding inhomogeneous dephasing time T2* for a nanotube-based valley qubit. We acknowledge funding from the EU Marie Curie CIG-293834, OTKA Grant PD 100373, and EU ERC Starting Grant CooPairEnt 258789. AP is supported by the Janos Bolyai Scholarship of the Hungarian Academy of Sciences.

Fort, Tower, or House? Building a Landscape of Settlement in the Shala Valley of High Albania

Directory of Open Access Journals (Sweden)

Michael L. Galaty

2010-01-01

Full Text Available This article presents the results of archaeological, (ethno-historic, and ethnographic research in the Shala River valley of northern Albania. We argue that through time and in different periods of occupation - Middle Palaeolithic, Iron Age, Late Medieval, and Modern - the valley's residents have met similar challenges of extreme geography and a harsh environment differently, in particular by interacting in different ways and at different levels of intensity with the outside world. These shifts caused changes in population, settlement, and socio-political organisation that are reflected strongly in the local landscape and built environment. Population, settlement, and socio-political organisation did not hold constant, but were influenced by external forces, despite the seeming isolation of the valley and its occupants. This article demonstrates how thin material and documentary records can be greatly enhanced through carefully integrated, interdisciplinary studies of settlement, home construction, and neighbourhood expansion and abandonment. We present select results drawn from an on-line database and GIS, along with photos, drawings, and audio recordings of transcribed interviews. An interactive system of blogs allows the authors to direct readers to additional sources of data, and readers to tell authors and other readers how they have accessed and displayed these data, and with what results.

Disorder-dependent valley properties in monolayer WSe2

KAUST Repository

Tran, Kha

2017-07-19

We investigate the effect of disorder on exciton valley polarization and valley coherence in monolayer WSe2. By analyzing the polarization properties of photoluminescence, the valley coherence (VC) and valley polarization (VP) are quantified across the inhomogeneously broadened exciton resonance. We find that disorder plays a critical role in the exciton VC, while affecting VP less. For different monolayer samples with disorder characterized by their Stokes shift (SS), VC decreases in samples with higher SS while VP does not follow a simple trend. These two methods consistently demonstrate that VC as defined by the degree of linearly polarized photoluminescence is more sensitive to disorder, motivating further theoretical studies.

Anisian and Ladinian Beds in the Cross-Section above Srednik Valley at Križna Gora,Central Slovenia

Directory of Open Access Journals (Sweden)

Matevž Demšar

2003-06-01

Full Text Available The Križna Gora and wider surroundings are built of the Paleozoic and Mesozoic rocks. Pretty extended among them are the carbonate Anisian and heterogeneously developed variegated Ladinian rocks wedging out laterally and vertically already at short distances as a result of active volcanism, tectonics and the fact that this region is situated on the margin between the Dinaric Carbonate Platform and the Slovenian Basin. The Ladinian rocks lie discordantly upon the Anisian dolomite. In the Ladinian sediments pelecypods Daonella lommeli (Wissmann are rather extended. The Ladinian beds are overlain by theCordevolian dolomite. The boundary between them in the Srednik Valley is strongly tektonized.

The Role of Source Material in Basin Sedimentation, as Illustrated within Eureka Valley, Death Valley National Park, CA.

Science.gov (United States)

Lawson, M. J.; Yin, A.; Rhodes, E. J.

2015-12-01

Steep landscapes are known to provide sediment to sink regions, but often petrological factors can dominate basin sedimentation. Within Eureka Valley, in northwestern Death Valley National Park, normal faulting has exposed a steep cliff face on the western margin of the Last Chance range with four kilometers of vertical relief from the valley floor and an angle of repose of nearly 38 degrees. The cliff face is composed of Cambrian limestone and dolomite, including the Bonanza King, Carrara and Wood Canyon formations. Interacting with local normal faulting, these units preferentially break off the cliff face in coherent blocks, which result in landslide deposits rather than as finer grained material found within the basin. The valley is well known for a large sand dune, which derives its sediment from distal sources to the north, instead of from the adjacent Last Chance Range cliff face. During the Holocene, sediment is sourced primary from the northerly Willow Wash and Cucomungo canyon, a relatively small drainage (less than 80 km2) within the Sylvan Mountains. Within this drainage, the Jurassic quartz monzonite of Beer Creek is heavily fractured due to motion of the Fish Valley Lake - Death Valley fault zone. Thus, the quartz monzonite is more easily eroded than the well-consolidated limestone and dolomite that forms the Last Change Range cliff face. As well, the resultant eroded material is smaller grained, and thus more easily transported than the limestone. Consequently, this work highlights an excellent example of the strong influence that source material can have on basin sedimentation.

Antifan activism as a response to MTV's The Valleys

Directory of Open Access Journals (Sweden)

Bethan Jones

2015-06-01

Full Text Available MTV has launched several reality TV shows in the United Kingdom, but one, The Valleys (2012–14, about youth moving from the South Wales Valleys to Cardiff, has received much criticism. Grassroots criticism of the show arose, and a Valleys-centric campaign, The Valleys Are Here, took direct action. I adopt Jonathan Gray's definition of antifans to complicate ideas of fan activism. I utilize comments and posts made on the Valleys Are Here Twitter feed and Facebook account, as well as the organization's Web site, to examine the ways in which they encourage activism among antifans of the series. I pay particular attention to activist calls for MTV to be held accountable for its positioning of Wales and the Valleys, and to how it encourages participation among varied groups of people whose common denominator is their dislike of the series. Fan activism is not exclusive to people who consider themselves fans, and notions of fan activism can be complicated by drawing in antifans.

The quasi-steady state of the valley wind system

Directory of Open Access Journals (Sweden)

Juerg eSchmidli

2015-12-01

Full Text Available The quasi-steady-state limit of the diurnal valley wind system is investigated overidealized three-dimensional topography. Although this limit is rarely attained inreality due to ever-changing forcings, the investigation of this limit canprovide valuable insight, in particular on the mass and heat fluxes associatedwith the along-valley wind. We derive a scaling relation for the quasi-steady-state along-valleymass flux as a function of valley geometry, valley size, atmospheric stratification,and surface sensible heat flux forcing. The scaling relation is tested by comparisonwith the mass flux diagnosed from numerical simulations of the valleywind system. Good agreement is found. The results also provide insight into the relationbetween surface friction and the strength of the along-valley pressure gradient.

Conservation Objectives for Wintering and Breeding Waterbirds in California’s Central Valley

Directory of Open Access Journals (Sweden)

W. David Shuford

2017-03-01

Full Text Available http://escholarship.org/uc/item/5tp5m718Birds associated with wetlands have declined historically across North America from extensive habitat loss and degradation. Among the regions most affected is California’s Central Valley, where over 90% of the wetland base has been lost. Still, this region remains of continental importance to waterbirds. On-the-ground conservation efforts for all bird groups are the focus of the Central Valley Joint Venture, guided by a periodically updated implementation plan. To track progress toward goal attainment, that plan sets time-bound, quantitative conservation goals. Lacking robust data on the size and trends of populations of most species of waterbirds in the Central Valley, we set conservation goals for this group by selecting 10 focal species. These species are of heightened conservation concern or are otherwise representative of the habitat needs of Central Valley waterbirds. Given the great loss of historical habitat, we assumed focal species populations have declined by ≥ 50%. Hence, we defined population objectives for most focal species as increasing their current populations by 10% over 10 years and doubling them in 100 years. The corresponding habitat objectives are to increase wetlands or enhance suitable crops for waterbirds in proportion to the population objectives. These include an increase over 10 years of 7,948 ha (19,641 acres of winter seasonal wetlands, 921 ha (2,276 acres each of semi-permanent and summer seasonal wetlands, and 573 ha (1,416 acres of strategically placed riparian forest. Agricultural needs include additional winter flooding of 15,160 ha (37,461 acres of rice and 2,137 ha (5,281 acres of corn. We distributed the habitat objectives across five planning regions, in some cases favoring proportionally larger increases in those regions with the greatest need. To maximize success, however, conservationists must take into account the specific needs of individual waterbird

Direct measurement of exciton valley coherence in monolayer WSe2

KAUST Repository

Hao, Kai

2016-02-29

In crystals, energy band extrema in momentum space can be identified by a valley index. The internal quantum degree of freedom associated with valley pseudospin indices can act as a useful information carrier, analogous to electronic charge or spin. Interest in valleytronics has been revived in recent years following the discovery of atomically thin materials such as graphene and transition metal dichalcogenides. However, the valley coherence time—a crucial quantity for valley pseudospin manipulation—is difficult to directly probe. In this work, we use two-dimensional coherent spectroscopy to resonantly generate and detect valley coherence of excitons (Coulomb-bound electron–hole pairs) in monolayer WSe₂ (refs ,). The imposed valley coherence persists for approximately one hundred femtoseconds. We propose that the electron–hole exchange interaction provides an important decoherence mechanism in addition to exciton population recombination. This work provides critical insight into the requirements and strategies for optical manipulation of the valley pseudospin for future valleytronics applications.

Photon wavelength dependent valley photocurrent in multilayer MoS2

Science.gov (United States)

Guan, Hongming; Tang, Ning; Xu, Xiaolong; Shang, LiangLiang; Huang, Wei; Fu, Lei; Fang, Xianfa; Yu, Jiachen; Zhang, Caifeng; Zhang, Xiaoyue; Dai, Lun; Chen, Yonghai; Ge, Weikun; Shen, Bo

2017-12-01

The degree of freedom (DOF) of the K (K') valley in transition-metal dichalcogenides, especially molybdenum disulfide (MoS2), offers an opportunity for next-generation valleytronics devices. In this work, the K (K') valley DOF of multilayer MoS2 is studied by means of the photon wavelength dependent circular photogalvanic effect (CPGE) at room temperature upon a strong external out-of-plane electric field induced by an ionic liquid (IL) gate, which breaks the spatial-inversion symmetry. It is demonstrated that only on resonant excitations in the K (K') valley can the valley-related CPGE signals in multilayer MoS2 with an IL gate be detected, indicating that the valley contrast is indeed regenerated between the K and K' valleys when the electric field is applied. As expected, it can also be seen that the K (K') valley DOF in multilayer MoS2 can be modulated by the external electric field. The observation of photon wavelength dependent valley photocurrent in multilayer MoS2, with the help of better Ohmic contacts, may pave a way for optoelectronic applications of valleytronics in the future.

Spin-valley splitting of electron beam in graphene

Directory of Open Access Journals (Sweden)

Yu Song

2016-11-01

Full Text Available We study spatial separation of the four degenerate spin-valley components of an electron beam in a EuO-induced and top-gated ferromagnetic/pristine/strained graphene structure. We show that, in a full resonant tunneling regime for all beam components, the formation of standing waves can lead sudden phase jumps ∼−π and giant lateral Goos-Hänchen shifts as large as the transverse beam width, while the interplay of the spin and valley imaginary wave vectors in the modulated regions can lead differences of resonant angles for the four spin-valley flavors, manifesting a spin-valley beam splitting effect. The splitting effect is found to be controllable by the gating and strain.

Climatic change in the Great Plains region of Canada

International Nuclear Information System (INIS)

Rizzo, B.

1991-01-01

Implications of global warming to Canada's Great Plains region are discussed, with reference to the climate predictions of the Goddard Institute for Space Studies (GISS) general circulation model under a two times atmospheric carbon dioxide concentration scenario. Two sets of climate variables for a geographic area located in the Great Plains are tabulated, for the current (1951-1980) climate normals and under the doubled carbon dioxide scenario. Simple univariate statistics were calculated for the two areas, for the variables of mean annual temperature, mean summer temperature, mean winter temperature, mean July temperature, mean growing season temperature, total annual precipitation, total summer precipitation, total winter precipitation, and total growing season precipitation. Under the GISS scenario, temperature values are on average 4 degree C higher than 1951-1980 normals, while precipitation remains about the same. Locations of ecoclimatic regions are graphed for the whole of Canada. 1 fig., 1 tab

A hydrogeologic map of the Death Valley region, Nevada, and California, developed using GIS techniques

International Nuclear Information System (INIS)

Faunt, C.C.; D'Agnese, F.A.; Turner, A.K.

1997-01-01

In support of Yucca Mountain site characterization studies, a hydrogeologic framework was developed, and a hydrogeologic map was constructed for the Death Valley region. The region, covering approximately 100,000 km 2 along the Nevada-California border near Las Vegas, is characterized by isolated mountain ranges juxtaposed against broad, alluvium-filled valleys. Geologic conditions are typical of the Basin and Range Province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. The regional ground-water flow system can best be described as a series of connected intermontane basins in which ground-water flow occurs in basin-fill deposits, carbonate rocks, clastic rocks, and volcanic rocks. Previous investigations have developed more site-specific hydrogeologic relationships; however, few have described all the lithologies within the Death Valley regional ground-water flow system. Information required to characterize the hydrogeologic units in the region was obtained from regional geologic maps and reports. Map data were digitized from regional geologic maps and combined into a composite map using a geographic information system. This map was simplified to show 10 laterally extensive hydrogeologic units with distinct hydrologic properties. The hydraulic conductivity values for the hydrogeologic units range over 15 orders of magnitude due to the variability in burial depth and degree of fracturing

Carbon Micronymphaea: Graphene on Vertically Aligned Carbon Nanotubes

Directory of Open Access Journals (Sweden)

Jong Won Choi

2013-01-01

Full Text Available This paper describes the morphology of carbon nanomaterials such as carbon nanotube (CNT, graphene, and their hybrid structure under various operating conditions during a one-step synthesis via plasma-enhanced chemical vapor deposition (PECVD. We focus on the synthetic aspects of carbon hybrid material composed of heteroepitaxially grown graphene on top of a vertical array of carbon nanotubes, called carbon micronymphaea. We characterize the structural features of this unique nanocomposite by uses of electron microscopy and micro-Raman spectroscopy. We observe carbon nanofibers, poorly aligned and well-aligned vertical arrays of CNT sequentially as the growth temperature increases, while we always discover the carbon hybrids, called carbon micronymphaea, at specific cooling rate of 15°C/s, which is optimal for the carbon precipitation from the Ni nanoparticles in this study. We expect one-pot synthesized graphene-on-nanotube hybrid structure poses great potential for applications that demand ultrahigh surface-to-volume ratios with intact graphitic nature and directional electronic and thermal transports.

Valley-polarized quantum transport generated by gauge fields in graphene

DEFF Research Database (Denmark)

Settnes, Mikkel; Garcia, Jose H; Roche, Stephan

2017-01-01

We report on the possibility to simultaneously generate in graphene a bulk valley-polarized dissipative transport and a quantum valley Hall effect by combining strain-induced gauge fields and real magnetic fields. Such unique phenomenon results from a ‘resonance/anti-resonance’ effect driven by t...... Kubo transport methods combined with a valley projection scheme to access valley-dependent conductivities and show that the results are robust against disorder....

Wintertime Ambient Ammonia Concentrations in Northern Utah's Urban Valleys

Science.gov (United States)

Hammond, I. A.; Martin, R. S.; Silva, P.; Baasandorj, M.

2017-12-01

Many of the population centers in northern Utah are currently classified as non-attainment or serious non-attainment, Wasatch Front, for PM2.5 and previous studies have shown ammonium nitrate to often be the largest contributor to the particulate mass. Furthermore, measurements have shown several of the Wasatch Front cities and Cache Valley (UT/ID) consistently recorded some of the highest ambient ammonia (NH3) concentrations in the continental United States. As a part of the multi-organization 2017 Utah Winter Fine Particulate Study real-time NH3 concentrations were monitored in the Cache Valley at the Logan, UT site, collocated at an EPA sampling trailer near the Utah State University (USU) campus. A Picarro model G2508 was to used collect 5-sec averaged concentrations of NH3, carbon dioxide (CO2), and methane (CH4) from January 16th to February 14th, 2017. Parts of three inversion events, wherein the PM2.5 concentrations approached or exceeded the National Ambient Air Quality Standards, were captured during the sampling period, including a 10-day event from January 25th to February 4th. Concentrations of all three of the observed species showed significant accumulation during the events, with NH3 concentrations ranging from below the detection limit (70 ppb. Preliminary analysis suggested the temporal NH3 changes tracked the increase in PM2.5 throughout the inversion events; however, a one-day period of NH3 depletion during the main inversion event was observed while PM2.5 continued to increase. Additionally, a network of passive NH3 samplers (Ogawa Model 3300) were arrayed at 25 sites throughout the Cache Valley and at 11 sites located along the Wasatch Front. These networks sampled for three 7-day periods, during the same study time frame. Ion chromatographic (IC) analyses of the sample pads are not yet finalized; however, preliminary results show concentrations in the tens of ppb and seemingly spatially correlate with previous studies showing elevated

Electrical control of the anomalous valley Hall effect in antiferrovalley bilayers

Science.gov (United States)

Tong, Wen-Yi; Duan, Chun-Gang

2017-08-01

In analogy to all-electric spintronics, all-electric valleytronics, i.e., valley manipulation via electric means, becomes an exciting new frontier as it may bring revolutions in the field of data storage with ultra-high speed and ultra-low power consumption. The existence of the anomalous valley Hall effect in ferrovalley materials demonstrates the possibility of electrical detection for valley polarization. However, in previously proposed valley-polarized monolayers, the anomalous valley Hall effect is controlled by external magnetic fields. Here, through elaborate structural design, we propose the antiferrovally bilayer as an ideal candidate for realizing all-electric valleytronic devices. Using the minimal k.p model, we show that the energy degeneracy between valley indexes in such system can be lifted by electric approaches. Subsequently, the anomalous valley Hall effect strongly depends on the electric field as well. Taking the bilayer VSe2 as an example, all-electric tuning and detecting of anomalous valley Hall effect is confirmed by density-functional theory calculations, indicating that the valley information in such antiferrovalley bilayer can be reversed by an electric field perpendicular to the plane of the system and easily probed through the sign of the Hall voltage.

The water balance of the urban Salt Lake Valley: a multiple-box model validated by observations

Science.gov (United States)

Stwertka, C.; Strong, C.

2012-12-01

A main focus of the recently awarded National Science Foundation (NSF) EPSCoR Track-1 research project "innovative Urban Transitions and Arid-region Hydro-sustainability (iUTAH)" is to quantify the primary components of the water balance for the Wasatch region, and to evaluate their sensitivity to climate change and projected urban development. Building on the multiple-box model that we developed and validated for carbon dioxide (Strong et al 2011), mass balance equations for water in the atmosphere and surface are incorporated into the modeling framework. The model is used to determine how surface fluxes, ground-water transport, biological fluxes, and meteorological processes regulate water cycling within and around the urban Salt Lake Valley. The model is used to evaluate the hypotheses that increased water demand associated with urban growth in Salt Lake Valley will (1) elevate sensitivity to projected climate variability and (2) motivate more attentive management of urban water use and evaporative fluxes.

A conceptual geochemical model of the geothermal system at Surprise Valley, CA

Science.gov (United States)

Fowler, Andrew P. G.; Ferguson, Colin; Cantwell, Carolyn A.; Zierenberg, Robert A.; McClain, James; Spycher, Nicolas; Dobson, Patrick

2018-03-01

Characterizing the geothermal system at Surprise Valley (SV), northeastern California, is important for determining the sustainability of the energy resource, and mitigating hazards associated with hydrothermal eruptions that last occurred in 1951. Previous geochemical studies of the area attempted to reconcile different hot spring compositions on the western and eastern sides of the valley using scenarios of dilution, equilibration at low temperatures, surface evaporation, and differences in rock type along flow paths. These models were primarily supported using classical geothermometry methods, and generally assumed that fluids in the Lake City mud volcano area on the western side of the valley best reflect the composition of a deep geothermal fluid. In this contribution, we address controls on hot spring compositions using a different suite of geochemical tools, including optimized multicomponent geochemistry (GeoT) models, hot spring fluid major and trace element measurements, mineralogical observations, and stable isotope measurements of hot spring fluids and precipitated carbonates. We synthesize the results into a conceptual geochemical model of the Surprise Valley geothermal system, and show that high-temperature (quartz, Na/K, Na/K/Ca) classical geothermometers fail to predict maximum subsurface temperatures because fluids re-equilibrated at progressively lower temperatures during outflow, including in the Lake City area. We propose a model where hot spring fluids originate as a mixture between a deep thermal brine and modern meteoric fluids, with a seasonally variable mixing ratio. The deep brine has deuterium values at least 3 to 4‰ lighter than any known groundwater or high-elevation snow previously measured in and adjacent to SV, suggesting it was recharged during the Pleistocene when meteoric fluids had lower deuterium values. The deuterium values and compositional characteristics of the deep brine have only been identified in thermal springs and

[Black carbon content and distribution in different particle size fractions of forest soils in the middle part of Great Xing'an Mountains, China.

Science.gov (United States)

Xu, Jia Hui; Gao, Lei; Cui, Xiao Yang

2017-10-01

Soil black carbon (BC) is considered to be the main component of passive C pool because of its inherent biochemical recalcitrance. In this paper, soil BC in the middle part of Great Xing'an Mountains was quantified, the distribution of BC in different particle size fractions was analyzed, and BC stabilization mechanism and its important role in soil C pool were discussed. The results showed that BC expressed obvious accumulation in surface soil, accounting for about 68.7% in the whole horizon (64 cm), and then decreased with the increasing soil depth, however, BC/OC showed an opposite pattern. Climate conditions redistributed BC in study area, and the soil under cooler and moister conditions would sequester more BC. BC proportion in different particle size fractions was in the order of clay>silt>fine sand>coarse sand. Although BC content in clay was the highest and was enhanced with increasing soil depth, BC/OC in clay did not show a marked change. Thus, the rise of BC/OC was attributed to the preservation of BC particles in the fine sand and silt fractions. Biochemical recalcitrance was the main stabilization mechanism for surface BC, and with the increasing soil depth, the chemical protection from clay mineral gradually played a predominant role. BC not only was the essential component of soil stable carbon pool, but also took up a sizable proportion in particulate organic carbon pool. Therefore, the storage of soil stable carbon and the potential of soil carbon sequestration would be enhanced owing to the existence of BC.

Chemical evolution of formation waters in the Palm Valley gas field, Northern Territory

International Nuclear Information System (INIS)

Andrew, A.S.; Giblin, A.M.

2000-01-01

The chemical composition and evolution of formation waters associated with gas production in the Palm Valley field, Northern Territory, has important implications for reservoir management, saline water disposal, and gas reserve calculations. Historically, the occurrence of saline formation water in gas fields has been the subject of considerable debate. A better understanding of the origin, chemical evolution and movement of the formation water at Palm Valley has important implications for future reservoir management, disposal of highly saline water and accurate gas reserves estimation. Major and trace element abundance data suggest that a significant component of the highly saline water from Palm Valley has characteristics that may have been derived from a modified evaporated seawater source such as an evaporite horizon. The most dilute waters probably represent condensate and the variation in the chemistry of the intermediate waters suggests they were derived from a mixture of the condensate with the highly saline brine. The chemical and isotopic results raise several interrelated questions; the ultimate source of the high salinity and the distribution of apparently mixed compositions. In this context several key observation are highlighted. Strontium concentrations are extremely high in the brines; although broadly similar in their chemistry, the saline fluids are neither homogeneous nor well mixed; the 87 Sr/ 86 Sr ratios in the brines are higher than the signatures preserved in the evaporitic Bitter Springs Formation, and all other conceivably marine-related evaporites (Strauss, 1993); the 87 Sr/ 86 Sr ratios in the brines are lower than those measured from groundmass carbonates in the host rocks, and that the 87 Sr/ 86 Sr ratios of the brines are similar, but still somewhat higher than those measured in vein carbonates from the reservoir. It is concluded that the high salinity brine entered the reservoir during the Devonian uplift and was subsequently

Titan's fluvial valleys: Morphology, distribution, and spectral properties

Science.gov (United States)

Langhans, M.H.; Jaumann, R.; Stephan, K.; Brown, R.H.; Buratti, B.J.; Clark, R.N.; Baines, K.H.; Nicholson, P.D.; Lorenz, R.D.; Soderblom, L.A.; Soderblom, J.M.; Sotin, Christophe; Barnes, J.W.; Nelson, R.

2012-01-01

Titan's fluvial channels have been investigated based on data obtained by the Synthetic Aperture Radar (SAR) instrument and the Visible and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft. In this paper, a database of fluvial features is created based on radar-SAR data aiming to unveil the distribution and the morphologic and spectral characteristics of valleys on Titan on a global scale. It will also study the spatial relations between fluvial valleys and Titan's geologic units and spectral surface units which have become accessible thanks to Cassini-VIMS data. Several distinct morphologic types of fluvial valleys can be discerned by SAR-images. Dendritic valley networks appear to have much in common with terrestrial dendritic systems owing to a hierarchical and tree-shaped arrangement of the tributaries which is indicative of an origin from precipitation. Dry valleys constitute another class of valleys resembling terrestrial wadis, an indication of episodic and strong flow events. Other valley types, such as putative canyons, cannot be correlated with rainfall based on their morphology alone, since it cannot be ruled out that they may have originated from volcanic/tectonic action or groundwater sapping. Highly developed and complex fluvial networks with channel lengths of up to 1200 km and widths of up to 10 km are concentrated only at a few locations whereas single valleys are scattered over all latitudes. Fluvial valleys are frequently found in mountainous areas. Some terrains, such as equatorial dune fields and undifferentiated plains at mid-latitudes, are almost entirely free of valleys. Spectrally, fluvial terrains are often characterized by a high reflectance in each of Titan's atmospheric windows, as most of them are located on Titan's bright 'continents'. Nevertheless, valleys are spatially associated with a surface unit appearing blue due to its higher reflection at 1.3??m in a VIMS false color RGB composite with R: 1.59/1.27??m, G: 2

Effects of permafrost thaw on carbon emissions under aerobic and anaerobic environments in the Great Hing'an Mountains, China.

Science.gov (United States)

Song, Changchun; Wang, Xianwei; Miao, Yuqing; Wang, Jiaoyue; Mao, Rong; Song, Yanyu

2014-07-15

The carbon (C) pool of permafrost peatland is very important for the global C cycle. Little is known about how permafrost thaw could influence C emissions in the Great Hing'an Mountains of China. Through aerobic and anaerobic incubation experiments, we studied the effects of permafrost thaw on CH4 and CO2 emissions. The rates of CH4 and CO2 emissions were measured at -10, 0 and 10°C. Although there were still C emissions below 0°C, rates of CH4 and CO2 emissions significantly increased with permafrost thaw under aerobic and anaerobic conditions. The C release under aerobic conditions was greater than under anaerobic conditions, suggesting that permafrost thaw and resulting soil environment change should be important influences on C emissions. However, CH4 stored in permafrost soils could affect accurate estimation of CH4 emissions from microbial degradation. Calculated Q10 values in the permafrost soils were significantly higher than values in active-layer soils under aerobic conditions. Our results highlight that permafrost soils have greater potential decomposability than soils of the active layer, and such carbon decomposition would be more responsive to the aerobic environment. © 2013 Elsevier B.V. All rights reserved.

Groundwater quality in Coachella Valley, California

Science.gov (United States)

Dawson, Barbara J. Milby; Belitz, Kenneth

2012-01-01

Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Coachella Valley is one of the study areas being evaluated. The Coachella study area is approximately 820 square miles (2,124 square kilometers) and includes the Coachella Valley groundwater basin (California Department of Water Resources, 2003). Coachella Valley has an arid climate, with average annual rainfall of about 6 inches (15 centimeters). The runoff from the surrounding mountains drains to rivers that flow east and south out of the study area to the Salton Sea. Land use in the study area is approximately 67 percent (%) natural, 21% agricultural, and 12% urban. The primary natural land cover is shrubland. The largest urban areas are the cities of Indio and Palm Springs (2010 populations of 76,000 and 44,000, respectively). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. The primary aquifers in Coachella Valley are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in Coachella Valley are completed to depths between 490 and 900 feet (149 to 274 meters), consist of solid casing from the land surface to a depth of 260 to 510 feet (79 to 155 meters), and are screened or perforated below the solid casing. Recharge to the groundwater system is primarily runoff from the surrounding mountains, and by direct infiltration of irrigation. The primary sources of discharge are pumping wells, evapotranspiration, and underflow to

Mid-latitude Ozone Depletion Events Caused by Halogens from the Great Salt Lake in Utah

Science.gov (United States)

Fibiger, D. L.; Goldberger, L.; Womack, C.; McDuffie, E. E.; Dube, W. P.; Franchin, A.; Middlebrook, A. M.; Thornton, J. A.; Brown, S. S.

2017-12-01

Halogens are highly reactive chemicals and play an important role in atmospheric chemistry. They can be involved in many cycles which influence the oxidizing capacity of the atmosphere, including through destruction of ozone (O3). While the influence of halogens on O3 is well documented in the arctic, there are very few observations of O3 depletion driven by halogens in the mid-latitudes. To date, the most comprehensive study observed co-occurring plumes of BrO and depleted O3 near the Dead Sea in 1997. During the Utah Wintertime Fine Particulate Study (UWFPS) in winter 2017, simultaneous measurements of a comprehensive suite of halogen measurements by I- chemical ionization mass spectrometry and O3 from cavity ring-down spectroscopy, both at 1-second time resolution, were taken on a NOAA Twin Otter Aircraft over the Great Salt Lake and in the surrounding valleys. Many O3 depletion events were observed over the lake with O3 values sometimes below the instrument detection limit of 0.5 ppbv. Corresponding increases in BrO and/or ClO were observed. Many of these events were caused by extremely high levels of halogens (up to 1 ppmv Cl2) emitted from the U.S. Magnesium plant on the edge of the lake. The O3 depletion caused by U.S. Magnesium was usually isolated to a distinct vertical layer, but in other cases O3 depletion was vertically mixed and the origin of halogen activation was not immediately clear. The most complete O3 depletion was observed over the lake, but there were smaller events of a few ppbv observed in the adjacent valleys, including the highly populated Salt Lake Valley, with corresponding plumes of BrO and ClO, due to transport from the lake. Additionally, meteorology played a role in the observed O3 depletion. The strongest O3 depletion was observed during inversion events, when there is a low boundary layer and little mixing out of the air above the lake. During non-inversion conditions, only small depletions were observed, covering a much smaller

2005 nonroad engine fleet characterization in the Canadian Lower Fraser Valley : final report

International Nuclear Information System (INIS)

Mak, J.; Chan, N.; Campbell, K.; Preston, K.; Bolechowsky, K.

2007-12-01

Metro Vancouver conducts an emission inventory for the Lower Fraser Valley on a five year basis. This report presented an estimate of the nonroad engine fleet population and emissions in the Canadian portion of the Lower Fraser Valley (CLFV). The nonroad engine fleet includes internal combustion engines of different fuel types used in mobile equipment such as on-road vehicles, aircraft, locomotives and ocean-going marine vessels. Some examples of nonroad equipment that were estimated included agricultural tractors; airport ground equipment; forklifts; excavators; generator sets; lawn mowers; railroad maintenance equipment; pleasure boats; and off-road motorcycles. The purpose of the study was to assist Metro Vancouver and other levels of government in determining what progress has been made in improving air quality, as well as the effect of policies and regulations on the environment in terms of nonroad vehicles. The report presented the objectives of the nonroad engine fleet characterization project which were to review the current data on nonroad engine populations and associated information, and confirm or improve the data through appropriate means; prepare estimates of 2005 emissions in the CLFV based on the revised engine counts using the United States Environmental Protection Agency's nonroad 2005 model; and prepare backcasts and forecasts of the 2005 nonroad engine emission estimates for 1990 to 2030 in five-year increments. Results were presented and analysed into the following 9 equipment type categories: agricultural, airport ground support, commercial, construction, industrial, lawn and garden, railway maintenance, recreational marine and recreational off-road vehicle. Four fuel types were considered for each type of equipment, notably gasoline, diesel, liquefied petroleum gases and compressed natural gas. The report described the methodologies and sources and presented the equipment population data. Emission results for carbon monoxide, nitrogen oxides

The power mix in Great-Britain

International Nuclear Information System (INIS)

Trebuchet, Charlotte

2012-11-01

This study addresses a new reform of the electric power sector in Great Britain: RIIO (Revenue = Incentives + Innovations + Outputs). The author discusses aspects related to market organisation and aspects related to the grid. First, she gives an overview of the situation of the electricity sector in Great-Britain by describing its evolution from the start of the liberalisation policy until our days, and by presenting the regulation of the electric power transport network. In a second part, she analyses which changes will be introduced by RIIO. She comments the general principles of this reform and discusses its implications for the sector. Appendices describe the LCN Fund (Low carbon network Fund) mechanism which is a specific bidding and selection process, and briefly indicate the projects selected by this fund in 2010 and 2011

Hydrology and numerical simulation of groundwater movement and heat transport in Snake Valley and surrounding areas, Juab, Miller, and Beaver Counties, Utah, and White Pine and Lincoln Counties, Nevada

Science.gov (United States)

Masbruch, Melissa D.; Gardner, Philip M.; Brooks, Lynette E.

2014-01-01

Snake Valley and surrounding areas, along the Utah-Nevada state border, are part of the Great Basin carbonate and alluvial aquifer system. The groundwater system in the study area consists of water in unconsolidated deposits in basins and water in consolidated rock underlying the basins and in the adjacent mountain blocks. Most recharge occurs from precipitation on the mountain blocks and most discharge occurs from the lower altitude basin-fill deposits mainly as evapotranspiration, springflow, and well withdrawals.The Snake Valley area regional groundwater system was simulated using a three-dimensional model incorporating both groundwater flow and heat transport. The model was constructed with MODFLOW-2000, a version of the U.S. Geological Survey’s groundwater flow model, and MT3DMS, a transport model that simulates advection, dispersion, and chemical reactions of solutes or heat in groundwater systems. Observations of groundwater discharge by evapotranspiration, springflow, mountain stream base flow, and well withdrawals; groundwater-level altitudes; and groundwater temperatures were used to calibrate the model. Parameter values estimated by regression analyses were reasonable and within the range of expected values.This study represents one of the first regional modeling efforts to include calibration to groundwater temperature data. The inclusion of temperature observations reduced parameter uncertainty, in some cases quite significantly, over using just water-level altitude and discharge observations. Of the 39 parameters used to simulate horizontal hydraulic conductivity, uncertainty on 11 of these parameters was reduced to one order of magnitude or less. Other significant reductions in parameter uncertainty occurred in parameters representing the vertical anisotropy ratio, drain and river conductance, recharge rates, and well withdrawal rates.The model provides a good representation of the groundwater system. Simulated water-level altitudes range over

Estimating Vehicular Emission in Kathmandu Valley, Nepal

Directory of Open Access Journals (Sweden)

Krishna Prasad Ghimire

2014-12-01

Full Text Available The study estimate, the vehicular emission load for CO, CO2 , HCs, NOX, SO2, Dioxin/Furans, Particulate Matters (PM10, PM2.5, Black carbon and Organic Carbon by using emission factors and Global Warming Potentials (GWPs of the pollutants (CO2, NOX, BC and OC. For this purpose, data were collected through the video tape record (in 30 sites, questionnaire survey, field visit, and literatures review. The total estimated emission of Kathmandu Valley (KV was 7231053.12 ton/year. Of the total emission, CO2 emission was highest i.e., 91.01% followed by CO 5.03%, HC 0.96%, NOX 0.60%, PM10 0.18% and SO2 0.10%. Annually 529353.36 μg Toxic Equivalent (TEQ of Dioxin/Furan produced and directly disperse to the ambient environment. The total estimated PM2.5, BC and OC emission were 9649.40 ton/year, 1640.4 ton/year and 2894.82 ton/year. The total carbon equivalence of the combined emissions (CO2, NOX and BC for 100-years standard time horizon is 10579763.6 ton CO2-eq i.e., 2885390.07 ton carbon.CO2 alone will be responsible, for about 62% of the impacts for the next century from current emissions of CO2, NOX and BC. Of the total emission Heavy Duty Vehicles (HDV emits 50%, Light Duty Vehicles (LDV emits, 27%, 2-Wheelers emits 22% and 3-Wheeler (Tempo emits 1%. The total emission of all pollutants combined per vehicle together was estimated to be 5.46 ton/year which was estimated as 23.63, 10.35, 1.83 and 5.58 ton/year for HDV, LDV, 2-Wheelers and 3-Wheeler respectively. DOI: http://dx.doi.org/10.3126/ije.v3i4.11742      International Journal of EnvironmentVolume-3, Issue-4, Sep-Nov 2014Page: 133-146 

Polyfluoroalkyl substance exposure in the Mid-Ohio River Valley, 1991-2012.

Science.gov (United States)

Herrick, Robert L; Buckholz, Jeanette; Biro, Frank M; Calafat, Antonia M; Ye, Xiaoyun; Xie, Changchun; Pinney, Susan M

2017-09-01

Industrial discharges of perfluorooctanoic acid (PFOA) to the Ohio River, contaminating water systems near Parkersburg, WV, were previously associated with nearby residents' serum PFOA concentrations above US general population medians. Ohio River PFOA concentrations downstream are elevated, suggesting Mid-Ohio River Valley residents are exposed through drinking water. Quantify PFOA and 10 other per- and polyfluoroalkyl substances (PFAS) in Mid-Ohio River Valley resident sera collected between 1991 and 2013 and determine whether the Ohio River and Ohio River Aquifer are exposure sources. We measured eleven PFAS in 1608 sera from 931 participants. Serum PFOA concentration and water source associations were assessed using linear mixed-effects models. We estimated between-sample serum PFOA using one-compartment pharmacokinetics for participants with multiple samples. In serum samples collected as early as 1991, PFOA (median = 7.6 ng/mL) was detected in 99.9% of sera; 47% had concentrations greater than US population 95th percentiles. Five other PFAS were detected in greater than 82% of samples; median other PFAS concentrations were similar to the US general population. Serum PFOA was significantly associated with water source, sampling year, age at sampling, tap water consumption, pregnancy, gravidity and breastfeeding. Serum PFOA was 40-60% lower with granular activated carbon (GAC) use. Repeated measurements and pharmacokinetics suggest serum PFOA peaked 2000-2006 for participants using water without GAC treatment; where GAC was used, serum PFOA concentrations decreased from 1991 to 2012. Mid-Ohio River Valley residents appear to have PFOA, but not other PFAS, serum concentrations above US population levels. Drinking water from the Ohio River and Ohio River Aquifer, primarily contaminated by industrial discharges 209-666 km upstream, is likely the primary exposure source. GAC treatment of drinking water mitigates, but does not eliminate, PFOA exposure. Copyright

Enhanced toxicity of aerosol in fog conditions in the Po Valley, Italy

Science.gov (United States)

Decesari, Stefano; Sowlat, Mohammad Hossein; Hasheminassab, Sina; Sandrini, Silvia; Gilardoni, Stefania; Facchini, Maria Cristina; Fuzzi, Sandro; Sioutas, Constantinos

2017-06-01

While numerous studies have demonstrated the association between outdoor exposure to atmospheric particulate matter (PM) and adverse health effects, the actual chemical species responsible for PM toxicological properties remain a subject of investigation. We provide here reactive oxygen species (ROS) activity data for PM samples collected at a rural site in the Po Valley, Italy, during the fog season (i.e., November-March). We show that the intrinsic ROS activity of Po Valley PM, which is mainly composed of biomass burning and secondary aerosols, is comparable to that of traffic-related particles in urban areas. The airborne concentration of PM components responsible for the ROS activity decreases in fog conditions, when water-soluble species are scavenged within the droplets. Due to this partitioning effect of fog, the measured ROS activity of fog water was contributed mainly by water-soluble organic carbon (WSOC) and secondary inorganic ions rather than by transition metals. We found that the intrinsic ROS activity of fog droplets is even greater (> 2.5 times) than that of the PM on which droplets are formed, indicating that redox-active compounds are not only scavenged from the particulate phase, but are also produced within the droplets. Therefore, even if fog formation exerts a scavenging effect on PM mass and redox-active compounds, the aqueous-phase formation of reactive secondary organic compounds can eventually enhance ROS activity of PM when fog evaporates. These findings, based on a case study during a field campaign in November 2015, indicate that a significant portion of airborne toxicity in the Po Valley is largely produced by environmental conditions (fog formation and fog processing) and not simply by the emission and transport of pollutants.

EPA Region 1 - Map Layers for Valley ID Tool (Hosted Feature Service)

Science.gov (United States)

The Valley Service Feature Layer hosts spatial data for EPA Region 1's Valley Identification Tool. These layers contain attribute information added by EPA R1 GIS Center to help identify populated valleys:- Fac_2011NEI: Pollution sources selected from the National Emissions Inventory (EPA, 2011).- NE_Towns_PopValleys: New England Town polygons (courtesy USGS), with Population in Valleys and Population Density in Valleys calculated by EPA R1 GIS, from 2010 US Census blocks. - VT_E911: Vermont residences (courtesy VT Center for Geographic Information E-911).

Valley photonic crystals for control of spin and topology

Energy Technology Data Exchange (ETDEWEB)

Dong, Jian-Wen; Chen, Xiao-Dong; Zhu, Hanyu; Wang, Yuan; Zhang, Xiang

2016-11-28

Photonic crystals offer unprecedented opportunity for light manipulation and applications in optical communication and sensing1,2,3,4. Exploration of topology in photonic crystals and metamaterials with non-zero gauge field has inspired a number of intriguing optical phenomena such as one-way transport and Weyl points5,6,7,8,9,10. Recently, a new degree of freedom, valley, has been demonstrated in two-dimensional materials11,12,13,14,15. Here, we propose a concept of valley photonic crystals with electromagnetic duality symmetry but broken inversion symmetry. We observe photonic valley Hall effect originating from valley-dependent spin-split bulk bands, even in topologically trivial photonic crystals. Valley–spin locking behaviour results in selective net spin flow inside bulk valley photonic crystals. We also show the independent control of valley and topology in a single system that has been long pursued in electronic systems, resulting in topologically-protected flat edge states. Valley photonic crystals not only offer a route towards the observation of non-trivial states, but also open the way for device applications in integrated photonics and information processing using spin-dependent transportation.

High-resolution aeromagnetic survey of the Mono Basin-Long Valley Caldera region, California

Science.gov (United States)

Ponce, D. A.; Mangan, M.; McPhee, D.

2013-12-01

A new high-resolution aeromagnetic survey of the Mono Basin-Long Valley Caldera region greatly enhances previous magnetic interpretations that were based on older, low-resolution, and regional aeromagnetic data sets and provides new insights into volcano-tectonic processes. The surveyed area covers a 8,750 km2 NNW-trending swath situated between the Sierra Nevada to the west and the Basin and Range Province to the east. The surveyed area includes the volcanic centers of Mono Lake, Mono-Inyo Craters, Mammoth Mountain, Devils Postpile, and Long Valley Caldera. The NW-trending eastern Sierra frontal fault zone crosses through the study area, including the active Mono Lake, Silver Lake, Hartley Springs, Laurel Creek, and Hilton Creek faults. Over 6,000 line-kilometers of aeromagnetic data were collected at a constant terrain clearance of 150 m, a flight-line spacing of 400 m, and a tie-line spacing of 4 km. Data were collected via helicopter with an attached stinger housing a magnetic sensor using a Scintrex CS-3 cesium magnetometer. In the northern part of the survey area, data improve the magnetic resolution of the individual domes and coulees along Mono Craters and a circular shaped magnetic anomaly that coincides with a poorly defined ring fracture mapped by Kistler (1966). Here, aeromagnetic data combined with other geophysical data suggests that Mono Craters may have preferentially followed a pre-existing plutonic basement feature that may have controlled the sickle shape of the volcanic chain. In the northeastern part of the survey, aeromagnetic data reveal a linear magnetic anomaly that correlates with and extends a mapped fault. In the southern part of the survey, in the Sierra Nevada block just south of Long Valley Caldera, aeromagnetic anomalies correlate with NNW-trending Sierran frontal faults rather than to linear NNE-trends observed in recent seismicity over the last 30 years. These data provide an important framework for the further analysis of the

77 FR 66429 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

Science.gov (United States)

2012-11-05

...EPA is proposing to approve revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of the California State Implementation Plan (SIP). These revisions concern volatile organic compounds (VOC), carbon monoxide (CO), oxides of nitrogen (NOX), oxides of sulfur (SOX), and particulate matter (PM) emissions from glass melting furnaces. We are approving a local rule that regulates these emission sources under the Clean Air Act (CAA or the Act). We are taking comments on this proposal and plan to follow with a final action.

Breathing Valley Fever

Centers for Disease Control (CDC) Podcasts

2014-02-04

Dr. Duc Vugia, chief of the Infectious Diseases Branch in the California Department of Public Health, discusses Valley Fever.  Created: 2/4/2014 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/5/2014.

Groundwater-flow and land-subsidence model of Antelope Valley, California

Science.gov (United States)

Siade, Adam J.; Nishikawa, Tracy; Rewis, Diane L.; Martin, Peter; Phillips, Steven P.

2014-01-01

Antelope Valley, California, is a topographically closed basin in the western part of the Mojave Desert, about 50 miles northeast of Los Angeles. The Antelope Valley groundwater basin is about 940 square miles and is separated from the northern part of Antelope Valley by faults and low-lying hills. Prior to 1972, groundwater provided more than 90 percent of the total water supply in the valley; since 1972, it has provided between 50 and 90 percent. Most groundwater pumping in the valley occurs in the Antelope Valley groundwater basin, which includes the rapidly growing cities of Lancaster and Palmdale. Groundwater-level declines of more than 270 feet in some parts of the groundwater basin have resulted in an increase in pumping lifts, reduced well efficiency, and land subsidence of more than 6 feet in some areas. Future urban growth and limits on the supply of imported water may increase reliance on groundwater.

Quaternary glaciation of the Tashkurgan Valley, Southeast Pamir

Science.gov (United States)

Owen, Lewis A.; Chen, Jie; Hedrick, Kathyrn A.; Caffee, Marc W.; Robinson, Alexander C.; Schoenbohm, Lindsay M.; Yuan, Zhaode; Li, Wenqiao; Imrecke, Daniel B.; Liu, Jinfeng

2012-07-01

The Quaternary glacial history of Tashkurgan valley, in the transition between the Pamir and Karakoram, in Xinjiang Province, China was examined using remote sensing, field mapping, geomorphic analysis of landforms and sediments, and 10Be terrestrial cosmogenic nuclide dating. Moraines were assigned to four glacial stages: 1) the Dabudaer glacial stage that dates to the penultimate glacial cycle and/or earlier, and may represent one or more glaciations; 2) the Tashkurgan glacial stage that dates to early last glacial, most likely Marine Oxygen Isotope Stage (MIS) 4; 3) the Hangdi glacial stage that dates to MIS 2, possibly early MIS 2; and 4) the Kuzigun glacial stage that dates to the MIS 2, possibly the global Last Glacial Maximum, and is younger than the Hangdi glacial stage. Younger moraines and rock glaciers are present at the heads of tributary valleys; but these were inaccessible because they are located close to politically sensitive borders with Pakistan, Afghanistan and Tajikistan. Glaciers during the Dabudaer glacial stage advanced into the central part of the Tashkurgan valley. During the Tashkurgan glacial stages, glaciers advanced several kilometers beyond the mouths of the tributary valleys into the Tashkurgan valley. Glaciers during the Hangdi and Kuzigun glacial stages advanced just beyond the mouths of the tributary valleys. Glaciation in this part of the Himalayan-Tibetan orogen is likely strongly controlled by northern hemisphere climate oscillations, although a monsoonal influence on glaciation cannot be ruled out entirely.

Potential hydrologic characterization wells in Amargosa Valley

International Nuclear Information System (INIS)

Lyles, B.; Mihevc, T.

1994-09-01

More than 500 domestic, agricultural, and monitoring wells were identified in the Amargosa Valley. From this list, 80 wells were identified as potential hydrologic characterization wells, in support of the US Department of Energy (DOE) Underground Test Area/Remedial Investigation and Feasibility Study (UGTA/RIFS). Previous hydrogeologic studies have shown that groundwater flow in the basin is complex and that aquifers may have little lateral continuity. Wells located more than 10 km or so from the Nevada Test Site (NTS) boundary may yield data that are difficult to correlate to sources from the NTS. Also, monitoring well locations should be chosen within the guidelines of a hydrologic conceptual model and monitoring plan. Since these do not exist at this time, recompletion recommendations will be restricted to wells relatively close (approximately 20 km) to the NTS boundary. Recompletion recommendations were made for two abandoned agricultural irrigation wells near the town of Amargosa Valley (previously Lathrop Wells), for two abandoned wildcat oil wells about 10 km southwest of Amargosa Valley, and for Test Well 5 (TW-5), about 10 km east of Amargosa Valley

MX Siting Investigation. Gravity Survey - Sevier Desert Valley, Utah.

Science.gov (United States)

1981-01-24

Cheyenne, Wyoming. DMAHTC reduces the data to Simple Bouguer Anomaly (see Section A1.4, Appendix Al.0). The Defense Mapping Agency Aerospace Center...Desert Valley, Utah ......... 2 2 Topographic Setting - Sevier Desert Valley, Utah . 3 LIST OF DRAWINGS Drawing Number 1 Complete Bouguer Anomaly...gravity stations were distributed throughout the valley at an approxi- mate interval of 1.4 miles (2.3 km). Drawing 1 is a Complete Bouguer Anomaly

The great Canadian oil patch : the petroleum era from birth to peak. 2. ed.

International Nuclear Information System (INIS)

Gray, E.

2004-01-01

This book presents a history of the petroleum industry from its early years to the present day. Anecdotal tales of pioneers in the industry were related, with reference to the birth of the oil industry, the Turner Valley, early energy waste issues, and accidents. Norman Wells and the Canol Project were discussed, as was the accident at Leduc and issues surrounding Pembina. Issues concerning the great pipeline debate and Trans-Canada were related. An overview of the oil sands industry was provided along with historical information on Arctic development and offshore oil. The National Oil Policy was considered, with reference to the oil crisis, economic development and the rise and fall of the National Energy Program. Survivors of the oil industry crisis were discussed, with reference to the remaining large independent producers. Issues surrounding the end of the oil and gas age were also examined, with reference to issues concerning renewable energy technologies and energy efficiency. The Kyoto Protocol was reviewed in relation to the oil and gas industry. It was concluded that currently, low market prices mask external costs such as air pollution. It was also noted that if energy prices continue to rise, energy efficiency will increase, thereby reducing the gap between fossil and alternative fuels. In addition, it was suggested that the incentive to capture carbon dioxide emissions and sequester them to recover more oil from old fields will increase. refs., tabs., figs

Gravity and magnetic data of Midway Valley, southwest Nevada

International Nuclear Information System (INIS)

Ponce, D.A.; Langenheim, V.E.; Sikora, R.F.

1993-01-01

Detailed gravity and ground magnetic data collected along five traverses across Midway Valley on the eastern flank of Yucca Mountain in southwest Nevada are described. These data were collected as part of an effort to evaluate faulting in the vicinity of proposed surface facilities for a potential nuclear waste repository at Yucca Mountain. Geophysical data show that Midway Valley is bounded by large gravity and magnetic anomalies associated with the Bow Ridge and Paintbrush Canyon faults, on the west side of Exile Hill and on the west flank of Fran Ridge, respectively. In addition, Midway Valley itself is characterized by a number of small-amplitude anomalies that probably reflect small-scale faulting beneath Midway Valley

27 CFR 9.208 - Snake River Valley.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Snake River Valley. 9.208... Snake River Valley. (a) Name. The name of the viticultural area described in this section is “Snake River Valley”. For purposes of part 4 of this chapter, “Snake River Valley” is a term of viticultural...

Subglacial tunnel valleys in the Alpine foreland: an example from Bern, Switzerland

International Nuclear Information System (INIS)

Duerst Stucki, M.; Reber, R.; Schlunegger, F.

2010-01-01

The morphology of the Alpine and adjacent landscapes is directly related to glacial erosion and associated sediment transport. Here we report the effects of glacio-hydrologic erosion on bedrock topography in the Swiss Plateau. Specifically, we identify the presence of subsurface valleys beneath the city of Bern and discuss their genesis. Stratigraphic investigations of more than 4'000 borehole data within a 430 km 2 -large area reveal the presence of a network of >200 m-deep and 1'000 m-wide valleys. They are flat floored with steep sided walls and are filled by Quaternary glacial deposits. The central valley beneath Bern is straight and oriented towards the NNW, with valley flanks more than 20 o steep. The valley bottom has an irregular undulating profile along the thalweg, with differences between sills and hollows higher than 50-100 m over a reach of 4 km length. Approximately 500 m high bedrock highlands flank the valley network. The highlands are dissected by up to 80 m-deep and 500 m-broad hanging valleys that currently drain away from the axis of the main valley. We interpret the valleys beneath the city of Bern to be a tunnel valley network which originated from subglacial erosion by melt water. The highland valleys served as proglacial meltwater paths and are hanging with respect to the trunk system, indicating that these incipient highland systems as well as the main gorge beneath Bern formed by glacial melt water under pressure. (authors)

Gate-tunable valley-spin filtering in silicene with magnetic barrier

Energy Technology Data Exchange (ETDEWEB)

Wu, X. Q., E-mail: xianqiangzhe@126.com [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Meng, H. [School of Physics and Telecommunication Engineering, Shanxi University of Technology, Hanzhong 723001 (China)

2015-05-28

We theoretically study the valley- and spin-resolved scattering through magnetic barrier in a one layer thick silicene, using the mode-matching method for the Dirac equation. We show that the spin-valley filtering effect can be achieved and can also be tuned completely through both a top and bottom gate. Moreover, when reversing the sign of the staggered potential, we find the direction of the valley polarization is switched while the direction of spin polarization is unchanged. These results can provide some meaningful information to design valley valve residing on silicene.

Economic Analysis of Sequestering Carbon in Green Ash Forests in the Lower Mississippi River Valley

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Ching-Hsun Huang

2003-01-01

Full Text Available Since the U.S. is the largest emitter of carbon dioxide (CO2, it has become crucial to develop options that are both cost effective and supportive of sustainable development to reduce atmospheric CO2. Electric utility companies have the options of reducing their use of fossil fuels, switching to alternative energy sources, increasing efficiency, or offsetting carbon emissions. This study determined the cost and profitability of sequestering carbon in green ash plantations, and the number of tons of carbon that can be sequestered. The profitability of green ash is $2,342 and $3,645 per acre on site indices (measurement of soil quality 65 and 105 land, respectively, calculated with a 2.5% alternative rate of return (ARR. These figures shift to –$248 and –$240 calculated with a 15.0% ARR. If landowners who have an ARR of 2.5% can sell carbon credits for $10 per ton of carbon, profits will increase by $107 per acre on poor sites and $242 on good sites. Over one rotation (cutting cycle, 38.56 net tons of carbon can be sequestered on an acre of poor quality land and 51.35 tons on good quality land. The cost of sequestering carbon, without including revenues from timber production and carbon credits, ranges from a high of $15.20 per ton on poor sites to $14.41 on good sites, calculated with a 2.5% ARR; to a high of $8.51 per ton on poor sites to $7.63 on good sites, calculated with a 15.0% ARR. The cost of storing carbon can be reduced significantly if the trees can be sold for wood products.

VALDRIFT 1.0: A valley atmospheric dispersion model with deposition

Energy Technology Data Exchange (ETDEWEB)

Allwine, K.J.; Bian, X.; Whiteman, C.D.

1995-05-01

VALDRIFT version 1.0 is an atmospheric transport and diffusion model for use in well-defined mountain valleys. It is designed to determine the extent of ddft from aedal pesticide spraying activities, but can also be applied to estimate the transport and diffusion of various air pollutants in valleys. The model is phenomenological -- that is, the dominant meteorological processes goveming the behavior of the valley atmosphere are formulated explicitly in the model, albeit in a highly parameterized fashion. The key meteorological processes treated are: (1) nonsteady and nonhomogeneous along-valley winds and turbulent diffusivities, (2) convective boundary layer growth, (3) inversion descent, (4) noctumal temperature inversion breakup, and (5) subsidence. The model is applicable under relatively cloud-free, undisturbed synoptic conditions and is configured to operate through one diumal cycle for a single valley. The inputs required are the valley topographical characteristics, pesticide release rate as a function of time and space, along-valley wind speed as a function of time and space, temperature inversion characteristics at sunrise, and sensible heat flux as a function of time following sunrise. Default values are provided for certain inputs in the absence of detailed observations. The outputs are three-dimensional air concentration and ground-level deposition fields as a function of time.

Valley-selective optical Stark effect probed by Kerr rotation

Science.gov (United States)

LaMountain, Trevor; Bergeron, Hadallia; Balla, Itamar; Stanev, Teodor K.; Hersam, Mark C.; Stern, Nathaniel P.

2018-01-01

The ability to monitor and control distinct states is at the heart of emerging quantum technologies. The valley pseudospin in transition metal dichalcogenide (TMDC) monolayers is a promising degree of freedom for such control, with the optical Stark effect allowing for valley-selective manipulation of energy levels in WS2 and WSe2 using ultrafast optical pulses. Despite these advances, understanding of valley-sensitive optical Stark shifts in TMDCs has been limited by reflectance-based detection methods where the signal is small and prone to background effects. More sensitive polarization-based spectroscopy is required to better probe ultrafast Stark shifts for all-optical manipulation of valley energy levels. Here, we show time-resolved Kerr rotation to be a more sensitive probe of the valley-selective optical Stark effect in monolayer TMDCs. Compared to the established time-resolved reflectance methods, Kerr rotation is less sensitive to background effects. Kerr rotation provides a fivefold improvement in the signal-to-noise ratio of the Stark effect optical signal and a more precise estimate of the energy shift. This increased sensitivity allows for observation of an optical Stark shift in monolayer MoS2 that exhibits both valley and energy selectivity, demonstrating the promise of this method for investigating this effect in other layered materials and heterostructures.

A 5000km2 data set along western Great Bahama Bank illustrates the dynamics of carbonate slope deposition

Science.gov (United States)

Schnyder, Jara S. D.; Jo, Andrew; Eberli, Gregor P.; Betzler, Christian; Lindhorst, Sebastian; Schiebel, Linda; Hebbeln, Dierk; Wintersteller, Paul; Mulder, Thierry; Principaud, Melanie

2014-05-01

An approximately 5000km2 hydroacoustic and seismic data set provides the high-resolution bathymetry map of along the western slope of Great Bahama Bank, the world's largest isolated carbonate platform. This large data set in combination with core and sediment samples, provides and unprecedented insight into the variability of carbonate slope morphology and the processes affecting the platform margin and the slope. This complete dataset documents how the interplay of platform derived sedimentation, distribution by ocean currents, and local slope and margin failure produce a slope-parallel facies distribution that is not governed by downslope gradients. Platform-derived sediments produce a basinward thinning sediment wedge that is modified by currents that change directions and strength depending on water depth and location. As a result, winnowing and deposition change with water depth and distance from the margin. Morphological features like the plunge pool and migrating antidunes are the result of currents flowing from the banktop, while the ocean currents produce contourites and drifts. These continuous processes are punctuated by submarine slope failures of various sizes. The largest of these slope failures produce several hundred of km2 of mass transport complexes and could generate tsunamis. Closer to the Cuban fold and thrust belt, large margin collapses pose an equal threat for tsunami generation. However, the debris from margin and slope failure is the foundation for a teeming community of cold-water corals.

Four newly recorded species of Dryopteridaceae from Kashmir valley, India

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SHAKOOR AHMAD MIR

2014-04-01

Full Text Available Mir SA, Mishra AK, Reshi ZA, Sharma MP. 2014. Four newly recorded species of Dryopteridaceae from Kashmir valley, India. Biodiversitas 15: 6-11. Habitat diversity, elevation, cloud cover, rainfall, seasonal and temperature variations have created many ideal sites for the luxuriant growth of pteridophytes in the Kashmir valley, yet all the regions of the valley have not been surveyed. In Kashmir valley the family Dryopteridaceae is represented by 31 species. During the recent extensive field surveys of Shopian district four more species viz., Dryopteris caroli-hopei Fraser-Jenkins, Dryopteris blanfordii subsp. nigrosquamosa (Ching Fraser-Jenkins, Dryopteris pulvinulifera (Bedd. Kuntze and Polystichum Nepalense (Spreng C. Chr. have been recorded for the first time from the valley. The taxonomic description, synonyms, distribution and photographs of each species are given in this article.

Ventilation potential during the emissions survey in Toluca Valley, Mexico

Science.gov (United States)

Ruiz Angulo, A.; Peralta, O.; Jurado, O. E.; Ortinez, A.; Grutter de la Mora, M.; Rivera, C.; Gutierrez, W.; Gonzalez, E.

2017-12-01

During the late-spring early-summer measurements of emissions and pollutants were carried out during a survey campaign at four different locations within the Toluca Valley. The current emissions inventory typically estimates the generation of pollutants based on pre-estimated values representing an entire sector function of their activities. However, those factors are not always based direct measurements. The emissions from the Toluca Valley are rather large and they could affect the air quality of Mexico City Valley. The air masses interchange between those two valleys is not very well understood; however, based on the measurements obtained during the 3 months campaign we looked carefully at the daily variability of the wind finding a clear signal for mountain-valley breeze. The ventilation coefficient is estimated and the correlations with the concentrations at the 4 locations and in a far away station in Mexico City are addressed in this work. Finally, we discuss the implication of the ventilation capacity in air quality for the system of Valleys that include Mexico City.

Surficial geology and soils of the Elmira-Williamsport region, New York and Pennsylvania, with a section on forest regions and great soil groups

Science.gov (United States)

Denny, Charles Storrow; Lyford, Walter Henry; Goodlett, J.C.

1963-01-01

The Elmira-Williamsport region, lying south of the Finger Lakes in central New York and northern Pennsylvania, is part of the Appalachian Plateaus physiographic province. A small segment of the Valley and Ridge province is included near the south border. In 1953 and 1954, the authors, a geologist and a soil scientist, made a reconnaissance of about 5,000 square miles extending southward from the Finger Lakes, N.Y., to Williamsport, Pa., and eastward from Wellsboro, Pa., to Towanda, Pa. Glacial drift of Wisconsin age, covering the central and most of the northern parts of the region, belongs to the Olean substage of MacClintock and Apfel. This drift is thin and patchy, is composed of the relatively soft sandstones, siltstone, shales, and conglomerates of the plateaus, commonly has a low calcium carbonate content, and is deeply leached. Mantling its surface are extensive rubbly colluvial deposits. No conspicuous terminal moraine marks the relatively straight border of Olean drift. The Valley Heads moraine of Fairchild near the south ends of the Finger Lakes is composed of relatively thick drift containing a considerable amount of somewhat resistant sedimentary and crystalline rocks. Commonly this drift has a relatively high carbonate content and is leached to only shallow depths. The Valley Heads drift is younger than Olean, but its precise age is undetermined. The age of the Olean is perhaps between Sangamon and Farmdale, on the basis of, in part, a carbon-14 date from peat at Otto, N.Y. All differences in soil development on these two Wisconsin drifts are clearly related to the lithology of the parent material or the drainage, rather than to weathering differing in kind or in duration. The authors believe that the soils are relatively young, are in equilibrium with the present environment, and contain few, if any, features acquired during past weathering intervals. The effect of tree throw on soil profiles and the presence of soils on slopes clearly indicate that

76 FR 16696 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

Science.gov (United States)

2011-03-25

...EPA is finalizing approval of revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVAPCD) portion of the California State Implementation Plan (SIP). These revisions were proposed in the Federal Register on November 5, 2010 and concern oxides of nitrogen (NOX), carbon monoxide (CO), oxides of sulfur (SO2) and particulate matter emissions from boilers, steam generators and process heaters greater than 5.0 MMbtu/hour. We are approving a local rule that regulates these emission sources under the Clean Air Act as amended in 1990 (CAA or the Act).

In-filled reservoirs serving as sediment archives to analyse soil organic carbon erosion – Taking a closer look at the Karoo rangelands

DEFF Research Database (Denmark)

Krenz, Juliane; Greenwood, Philip; Kuhn, Brigitte

The semi-arid rangelands of the Great Karoo region in South Africa, which are nowadays characterized by badlands on the foot slopes of upland areas and complex gully systems in valley bottoms, have experienced a number of environmental changes. With the settlement of European farmers in the late ......th century agricultural activities increased, leading to overgrazing which probably acted as a trigger to land degradation. As a consequence of higher water demands and shifting rainfall patterns, many dams and small reservoirs have been constructed to provide drinking water for cattle...... or to facilitate irrigation during dry periods. Most of these dams are now filled with sediment and many have become breached, revealing sediment archives that can be used to analyse land use changes as well as carbon erosion and deposition during the last ca. 100 years. In this ongoing project, a combination...

Subglacial tunnel valleys in the Alpine foreland: an example from Bern, Switzerland

Energy Technology Data Exchange (ETDEWEB)

Duerst Stucki, M.; Reber, R.; Schlunegger, F.

2010-12-15

The morphology of the Alpine and adjacent landscapes is directly related to glacial erosion and associated sediment transport. Here we report the effects of glacio-hydrologic erosion on bedrock topography in the Swiss Plateau. Specifically, we identify the presence of subsurface valleys beneath the city of Bern and discuss their genesis. Stratigraphic investigations of more than 4'000 borehole data within a 430 km{sup 2}-large area reveal the presence of a network of >200 m-deep and 1'000 m-wide valleys. They are flat floored with steep sided walls and are filled by Quaternary glacial deposits. The central valley beneath Bern is straight and oriented towards the NNW, with valley flanks more than 20 {sup o} steep. The valley bottom has an irregular undulating profile along the thalweg, with differences between sills and hollows higher than 50-100 m over a reach of 4 km length. Approximately 500 m high bedrock highlands flank the valley network. The highlands are dissected by up to 80 m-deep and 500 m-broad hanging valleys that currently drain away from the axis of the main valley. We interpret the valleys beneath the city of Bern to be a tunnel valley network which originated from subglacial erosion by melt water. The highland valleys served as proglacial meltwater paths and are hanging with respect to the trunk system, indicating that these incipient highland systems as well as the main gorge beneath Bern formed by glacial melt water under pressure. (authors)

Ozone Laminae and Their Entrainment Into a Valley Boundary Layer, as Observed From a Mountaintop Monitoring Station, Ozonesondes, and Aircraft Over California's San Joaquin Valley

Science.gov (United States)

Faloona, I. C.; Conley, S. A.; Caputi, D.; Trousdell, J.; Chiao, S.; Eiserloh, A. J., Jr.; Clark, J.; Iraci, L. T.; Yates, E. L.; Marrero, J. E.; Ryoo, J. M.; McNamara, M. E.

2016-12-01

The San Joaquin Valley of California is wide ( 75 km) and long ( 400 km), and is situated under strong atmospheric subsidence due, in part, to the proximity of the midlatitude anticyclone of the Pacific High. The capping effect of this subsidence is especially prominent during the warm season when ground level ozone is a serious air quality concern across the region. While relatively clean marine boundary layer air is primarily funneled into the valley below the strong subsidence inversion at significant gaps in the upwind Coast Range mountains, airflow aloft also spills over these barriers and mixes into the valley from above. Because this transmountain flow occurs under the influence of synoptic subsidence it tends to present discrete, laminar sheets of differing air composition above the valley boundary layer. Meanwhile, although the boundary layers tend to remain shallow due to the prevailing subsidence, orographic and anabatic venting of valley boundary layer air around the basin whips up a complex admixture of regional air masses into a "buffer layer" just above the boundary layer (zi) and below the lower free troposphere. We present scalar data of widely varying lifetimes including ozone, methane, NOx, and thermodynamic observations from upwind and within the San Joaquin Valley to better explain this layering and its subsequent erosion into the valley boundary layer via entrainment. Data collected at a mountaintop monitoring station on Chews Ridge in the Coast Range, by coastal ozonesondes, and aircraft are analyzed to document the dynamic layering processes around the complex terrain surrounding the valley. Particular emphasis will be made on observational methods whereby distal ozone can be distinguished from the regional ozone to better understand the influence of exogenous sources on air quality in the valley.

Organic geochemistry and brine composition in Great Salt, Mono, and Walker Lakes

Science.gov (United States)

Domagalski, Joseph L.; Orem, W.H.; Eugster, H.P.

1989-01-01

Samples of Recent sediments, representing up to 1000 years of accumulation, were collected from three closed basin lakes (Mono Lake, CA, Walker Lake, NV, and Great Salt Lake, UT) to assess the effects of brine composition on the accumulation of total organic carbon, the concentration of dissolved organic carbon, humic acid structure and diagenesis, and trace metal complexation. The Great Salt Lake water column is a stratified Na-Mg-Cl-SO4 brine with low alkalinity. Algal debris is entrained in the high density (1.132-1.190 g/cc) bottom brines, and in this region maximum organic matter decomposition occurs by anaerobic processes, with sulfate ion as the terminal electron acceptor. Organic matter, below 5 cm of the sediment-water interface, degrades at a very slow rate in spite of very high pore-fluid sulfate levels. The organic carbon concentration stabilizes at 1.1 wt%. Mono Lake is an alkaline (Na-CO3-Cl-SO4) system. The water column is stratified, but the bottom brines are of lower density relative to the Great Salt Lake, and sedimentation of algal debris is rapid. Depletion of pore-fluid sulfate, near l m of core, results in a much higher accumulation of organic carbon, approximately 6 wt%. Walker Lake is also an alkaline system. The water column is not stratified, and decomposition of organic matter occurs by aerobic processes at the sediment-water interface and by anaerobic processes below. Total organic carbon and dissolved organic carbon concentrations in Walker Lake sediments vary with location and depth due to changes in input and pore-fluid sulfate concentrations. Nuclear magnetic resonance studies (13C) of humic substances and dissolved organic carbon provide information on the source of the Recent sedimentary organic carbon (aquatic vs. terrestrial), its relative state of decomposition, and its chemical structure. The spectra suggest an algal origin with little terrestrial signature at all three lakes. This is indicated by the ratio of aliphatic to

Geomorphological hazards in Swat valley, Pakistan

International Nuclear Information System (INIS)

Usman, A.

1999-01-01

This study attempts to describe, interpret and analyze, in depth, the varied geomorphological hazards and their impacts prevailing in the swat valley locate in the northern hilly and mountainous regions of Pakistan. The hills and mountains re zones of high geomorphological activity with rapid rates of weathering, active tectonic activities, abundant precipitation, rapid runoff and heavy sediment transport. Due to the varied topography, lithology, steep slope, erodible soil, heavy winter snowfall and intensive rainfall in the spring and summer seasons, several kinds of geomorphological hazards, such as geomorphic gravitational hazards, Fluvial hazards, Glacial hazards, Geo tectonic hazards, are occurring frequently in swat valley. Amongst them, geomorphic gravitational hazards, such as rock fall rock slide, debris slide mud flow avalanches, are major hazards in mountains and hills while fluvial hazards and sedimentation are mainly confined to the alluvial plain and lowlands of the valley. The Getechtonic hazards, on the other hand, have wide spread distribution in the valley the magnitude and occurrence of each king of hazard is thus, varied according to intensity of process and physical geographic environment. This paper discusses the type distribution and damage due to the various geomorphological hazards and their reduction treatments. The study would to be of particular importance and interest to both natural and social scientists, as well as planner, environmentalists and decision-makers for successful developmental interventions in the region. (author)

A new Proposal to Mexico Valley Zonification

Science.gov (United States)

Flores-Estrella, H. C.; Yussim, S.; Lomnitz, C.

2004-12-01

The effects of the Michoacan earthquake (19th September, 1985, Mw 8.1) in Mexico City caused a significant change in the political, social and scientific history, as it was considered the worst seismic disaster ever lived in Mexico. Since then, numerous efforts have been made to understand and determine the parameters that caused the special features registered. One of these efforts had began on 1960 with the work by Marsal and Masari, who published the Mexico Valley seismological and geotechnical zonification (1969), based on gravimetric and shallow borehole data. In this work, we present a revision of the studies that proposed the zonification, a description of the valley geology, and basing on it we propose a new zonification for Mexico Valley.

Hybrid spin and valley quantum computing with singlet-triplet qubits.

Science.gov (United States)

Rohling, Niklas; Russ, Maximilian; Burkard, Guido

2014-10-24

The valley degree of freedom in the electronic band structure of silicon, graphene, and other materials is often considered to be an obstacle for quantum computing (QC) based on electron spins in quantum dots. Here we show that control over the valley state opens new possibilities for quantum information processing. Combining qubits encoded in the singlet-triplet subspace of spin and valley states allows for universal QC using a universal two-qubit gate directly provided by the exchange interaction. We show how spin and valley qubits can be separated in order to allow for single-qubit rotations.

The physiological response of two green calcifying algae from the Great Barrier Reef towards high dissolved inorganic and organic carbon (DIC and DOC availability.

Directory of Open Access Journals (Sweden)

Friedrich Wilhelm Meyer

Full Text Available Increasing dissolved inorganic carbon (DIC concentrations associated with ocean acidification can affect marine calcifiers, but local factors, such as high dissolved organic carbon (DOC concentrations through sewage and algal blooms, may interact with this global factor. For calcifying green algae of the genus Halimeda, a key tropical carbonate producer that often occurs in coral reefs, no studies on these interactions have been reported. These data are however urgently needed to understand future carbonate production. Thus, we investigated the independent and combined effects of DIC (pCO2 402 μatm/ pHtot 8.0 and 996 μatm/ pHtot 7.7 and DOC (added as glucose in 0 and 294 μmol L-1 on growth, calcification and photosynthesis of H. macroloba and H. opuntia from the Great Barrier Reef in an incubation experiment over 16 days. High DIC concentrations significantly reduced dark calcification of H. opuntia by 130 % and led to net dissolution, but did not affect H. macroloba. High DOC concentrations significantly reduced daily oxygen production of H. opuntia and H. macroloba by 78 % and 43 %, respectively, and significantly reduced dark calcification of H. opuntia by 70%. Combined high DIC and DOC did not show any interactive effects for both algae, but revealed additive effects for H. opuntia where the combination of both factors reduced dark calcification by 162 % compared to controls. Such species-specific differences in treatment responses indicate H. opuntia is more susceptible to a combination of high DIC and DOC than H. macroloba. From an ecological perspective, results further suggest a reduction of primary production for Halimeda-dominated benthic reef communities under high DOC concentrations and additional decreases of carbonate accretion under elevated DIC concentrations, where H. opuntia dominates the benthic community. This may reduce biogenic carbonate sedimentation rates and hence the buffering capacity against further ocean

The physiological response of two green calcifying algae from the Great Barrier Reef towards high dissolved inorganic and organic carbon (DIC and DOC) availability.

Science.gov (United States)

Meyer, Friedrich Wilhelm; Vogel, Nikolas; Teichberg, Mirta; Uthicke, Sven; Wild, Christian

2015-01-01

Increasing dissolved inorganic carbon (DIC) concentrations associated with ocean acidification can affect marine calcifiers, but local factors, such as high dissolved organic carbon (DOC) concentrations through sewage and algal blooms, may interact with this global factor. For calcifying green algae of the genus Halimeda, a key tropical carbonate producer that often occurs in coral reefs, no studies on these interactions have been reported. These data are however urgently needed to understand future carbonate production. Thus, we investigated the independent and combined effects of DIC (pCO2 402 μatm/ pHtot 8.0 and 996 μatm/ pHtot 7.7) and DOC (added as glucose in 0 and 294 μmol L-1) on growth, calcification and photosynthesis of H. macroloba and H. opuntia from the Great Barrier Reef in an incubation experiment over 16 days. High DIC concentrations significantly reduced dark calcification of H. opuntia by 130 % and led to net dissolution, but did not affect H. macroloba. High DOC concentrations significantly reduced daily oxygen production of H. opuntia and H. macroloba by 78 % and 43 %, respectively, and significantly reduced dark calcification of H. opuntia by 70%. Combined high DIC and DOC did not show any interactive effects for both algae, but revealed additive effects for H. opuntia where the combination of both factors reduced dark calcification by 162 % compared to controls. Such species-specific differences in treatment responses indicate H. opuntia is more susceptible to a combination of high DIC and DOC than H. macroloba. From an ecological perspective, results further suggest a reduction of primary production for Halimeda-dominated benthic reef communities under high DOC concentrations and additional decreases of carbonate accretion under elevated DIC concentrations, where H. opuntia dominates the benthic community. This may reduce biogenic carbonate sedimentation rates and hence the buffering capacity against further ocean acidification.

Graphene valley pseudospin filter using an extended line defect

Science.gov (United States)

Gunlycke, Daniel; White, Carter

2011-03-01

Although graphene exhibits excellent electron and thermal transport properties, it does not have an intrinsic band gap, required to use graphene as a replacement material for silicon and other semiconductors in conventional electronics. The band structure of graphene with its two cones near the Fermi level, however, offers opportunities to develop non-traditional applications. One such avenue is to exploit the valley degeneracy in graphene to develop valleytronics. A central component in valleytronics is the valley filter, just as the spin filter is central in spintronics. Herein, we present a two-dimensional valley filter based on scattering of electrons and holes off a recently observed extended line defect [Nat. Nanotech.5, 326 (2010)] within graphene. The transmission probability depends strongly on the valley pseudospin and the angle of incidence of the incident quasiparticles. Quasiparticles arriving at the line defect at a high angle of incidence lead to a valley polarization of the transmitted beam that is near 100 percent. This work was supported by ONR, directly and through NRL.

Geomorphological evidences of Quaternary tectonic activities in the Santa Cruz river valley, Patagonia, Argentina

International Nuclear Information System (INIS)

Massabie, A.; Sanguinetti, A.; Nestiero, O.

2007-01-01

From Argentin lake, at west on Andean hills, to Puerto Santa Cruz on Atlantic coast, Santa Cruz river cross eastward Santa Cruz province over 250 km in Patagonia at southern Argentina. Present bed of the river has a meandering outline with first order meanders of great ratio bends and second order meanders of minor ratio bends. Principal wanderings are 45 to 55 km spaced from near Estancia La Julia or Rio Bote at west to Comandante Luis Piedrabuena at east. On river's bed middle sector these great curvatures are located at Estancia Condor Cliff and Estancia Rincon Grande. Regional and partial detailed studies allow to recognize structural control on river's bed sketch and valley s geomorphology that relates first order bends with reactivated principal faults. These faults fit well with parallel system of northwest strike of Austral Basin.On geological, geomorphologic and structural evidences recognized in Santa Cruz river, quaternary tectonic activity, related to Andean movements in southern Patagonian foreland, is postulated. (author)

Hydrological responses to channelization and the formation of valley plugs and shoals

Science.gov (United States)

Pierce, Aaron R.; King, Sammy L.

2017-01-01

Rehabilitation of floodplain systems focuses on restoring interactions between the fluvial system and floodplain, however, there is a paucity of information on the effects of valley plugs and shoals on floodplain hydrological processes. We investigated hydrologic regimes in floodplains at three valley plug sites, two shoal sites, and three unchannelized sites. Valley plug sites had altered surface and sub-surface hydrology relative to unchannelized sites, while only sub-surface hydrology was affected at shoal sites. Some of the changes were unexpected, such as reduced flood duration and flood depth in floodplains associated with valley plugs. Our results emphasize the variability associated with hydrologic processes around valley plugs and our rudimentary understanding of the effects associated with these geomorphic features. Water table levels were lower at valley plug sites compared to unchannelized sites, however, valley plug sites had a greater proportion of days when water table inundation was above mean root collar depth than both shoal and unchannelized sites as a result of lower root collar depths and higher deposition rates. This study has provided evidence that valley plugs can affect both surface and sub-surface hydrology in different ways than previously thought and illustrates the variability in hydrological responses to valley plug formation.

Geographic variability in elevation and topographic constraints on the distribution of native and nonnative trout in the Great Basin

Science.gov (United States)

Warren, Dana R.; Dunham, Jason B.; Hockman-Wert, David

2014-01-01

Understanding local and geographic factors influencing species distributions is a prerequisite for conservation planning. Our objective in this study was to model local and geographic variability in elevations occupied by native and nonnative trout in the northwestern Great Basin, USA. To this end, we analyzed a large existing data set of trout presence (5,156 observations) to evaluate two fundamental factors influencing occupied elevations: climate-related gradients in geography and local constraints imposed by topography. We applied quantile regression to model upstream and downstream distribution elevation limits for each trout species commonly found in the region (two native and two nonnative species). With these models in hand, we simulated an upstream shift in elevation limits of trout distributions to evaluate potential consequences of habitat loss. Downstream elevation limits were inversely associated with latitude, reflecting regional gradients in temperature. Upstream limits were positively related to maximum stream elevation as expected. Downstream elevation limits were constrained topographically by valley bottom elevations in northern streams but not in southern streams, where limits began well above valley bottoms. Elevation limits were similar among species. Upstream shifts in elevation limits for trout would lead to more habitat loss in the north than in the south, a result attributable to differences in topography. Because downstream distributions of trout in the north extend into valley bottoms with reduced topographic relief, trout in more northerly latitudes are more likely to experience habitat loss associated with an upstream shift in lower elevation limits. By applying quantile regression to relatively simple information (species presence, elevation, geography, topography), we were able to identify elevation limits for trout in the Great Basin and explore the effects of potential shifts in these limits that could occur in response to changing

Carbon cycle history through the Middle Jurassic (Aalenian - Bathonian) of the Mecsek Mountains, Southern Hungary

Science.gov (United States)

Price, Gregory D.; Főzy, István; Galácz, András

2018-04-01

A carbonate carbon isotope curve from the Aalenian-Bathonian interval is presented from the Óbánya valley, of the Mecsek Mountains, Hungary. This interval is certainly less well constrained and studied than other Jurassic time slices. The Óbánya valley lies in the eastern part of the Mecsek Mountains, between Óbánya and Kisújbánya and provides exposures of an Aalenian to Lower Cretaceous sequence. It is not strongly affected by tectonics, as compared to other sections of eastern Mecsek of the same age. In parts, a rich fossil assemblage has been collected, with Bathonian ammonites being especially valuable at this locality. The pelagic Middle Jurassic is represented by the Komló Calcareous Marl Formation and thin-bedded limestones of the Óbánya Limestone Formation. These are overlain by Upper Jurassic siliceous limestones and radiolarites of the Fonyászó Limestone Formation. Our new data indicate a series of carbon isotope anomalies within the late Aalenian and early-middle Bajocian. In particular, analysis of the Komló Calcareous Marl Formation reveals a negative carbon isotope excursion followed by positive values that occurs near the base of the section (across the Aalenian-Bajocian boundary). The origin of this carbon-isotope anomaly is interpreted to lie in significant changes to carbon fluxes potentially stemming from reduced run off, lowering the fertility of surface waters which in turn leads to lessened primary production and a negative δ13C shift. These data are comparable with carbonate carbon isotope records from other Tethyan margin sediments. Our integrated biostratigraphy and carbon isotope stratigraphy enable us to improve stratigraphic correlation and age determination of the examined strata. Therefore, this study of the Komló Calcareous Marl Formation confirms that the existing carbon isotope curves serve as a global standard for Aalenian-Bathonian δ13C variation.

Numerical simulation of the impact of reforestation on winter meteorology and environment in a semi-arid urban valley, Northwestern China

International Nuclear Information System (INIS)

Yu, Ye; He, Jianjun; Zhao, Suping; Liu, Na; Chen, Jinbei; Mao, Hongjun; Wu, Lin

2016-01-01

Since 1999 Chinese government has made great effort to reforest the south and north mountains surrounding urban Lanzhou – a city located in a river valley, Northwestern China. Until 2009 obvious land use change occurred, with 69.2% of the reforested area been changed from grasslands, croplands, barren or sparsely vegetated land to closed shrublands and 20.6% from closed shrublands, grasslands, and croplands to forests. Reforestation changes land-surface properties, with possible impact on the evolution of atmospheric variables. To understand to what extent the local meteorology and environment could be affected by reforestation in winter, and through what processes, two sets of simulations were conducted using the Weather Research and Forecasting model (WRF) and the FLEXible PARTicle (FLEXPART) dispersion model for a control case with high-resolution remotely sensed land cover data for 2009 and a scenario assuming no reforestation since 1999. Results suggested that the changes in albedo, surface exchange coefficient and surface soil heat conductivity related to reforestation led to the changes in surface net radiation and surface energy partitioning, which in turn affected the meteorological fields and enhanced the mountain-valley wind circulation. Replacement of shrublands and grassland with forest in the south mountain through reforestation play a dominant role in the enhancement of mountain-valley wind circulation. Reforestation increased the amount of air exchanged between the valley and the outside during the day, with the largest hourly increase of 10% on calm weather days and a monthly mean hourly increase of 2% for the study period (Dec. 2009). Reforestation affected the spatial distribution of pollutants and slightly improved the urban air quality, especially in the eastern valley. Results from this study provide useful information for future urban air quality management and reforestation plan, and some experience for cities with similar situations in

Numerical simulation of the impact of reforestation on winter meteorology and environment in a semi-arid urban valley, Northwestern China

Energy Technology Data Exchange (ETDEWEB)

Yu, Ye, E-mail: yyu@lzb.ac.cn [Clod and Arid Regions Environmental and Engineering Research Institute, Key Laboratory of Land Surface Process and Climate Change in Cold & Arid Regions, Chinese Academy of Sciences, Lanzhou 730000 (China); He, Jianjun, E-mail: 18766167147@163.com [Clod and Arid Regions Environmental and Engineering Research Institute, Key Laboratory of Land Surface Process and Climate Change in Cold & Arid Regions, Chinese Academy of Sciences, Lanzhou 730000 (China); College of Environmental Science & Engineering, Nankai University, Tianjin 300071 (China); Zhao, Suping [Clod and Arid Regions Environmental and Engineering Research Institute, Key Laboratory of Land Surface Process and Climate Change in Cold & Arid Regions, Chinese Academy of Sciences, Lanzhou 730000 (China); Liu, Na [Clod and Arid Regions Environmental and Engineering Research Institute, Key Laboratory of Land Surface Process and Climate Change in Cold & Arid Regions, Chinese Academy of Sciences, Lanzhou 730000 (China); Weather Modification Office, Qinghai Meteorological Bureau, Xining 810001 (China); Chen, Jinbei [Clod and Arid Regions Environmental and Engineering Research Institute, Key Laboratory of Land Surface Process and Climate Change in Cold & Arid Regions, Chinese Academy of Sciences, Lanzhou 730000 (China); Mao, Hongjun; Wu, Lin [College of Environmental Science & Engineering, Nankai University, Tianjin 300071 (China)

2016-11-01

Since 1999 Chinese government has made great effort to reforest the south and north mountains surrounding urban Lanzhou – a city located in a river valley, Northwestern China. Until 2009 obvious land use change occurred, with 69.2% of the reforested area been changed from grasslands, croplands, barren or sparsely vegetated land to closed shrublands and 20.6% from closed shrublands, grasslands, and croplands to forests. Reforestation changes land-surface properties, with possible impact on the evolution of atmospheric variables. To understand to what extent the local meteorology and environment could be affected by reforestation in winter, and through what processes, two sets of simulations were conducted using the Weather Research and Forecasting model (WRF) and the FLEXible PARTicle (FLEXPART) dispersion model for a control case with high-resolution remotely sensed land cover data for 2009 and a scenario assuming no reforestation since 1999. Results suggested that the changes in albedo, surface exchange coefficient and surface soil heat conductivity related to reforestation led to the changes in surface net radiation and surface energy partitioning, which in turn affected the meteorological fields and enhanced the mountain-valley wind circulation. Replacement of shrublands and grassland with forest in the south mountain through reforestation play a dominant role in the enhancement of mountain-valley wind circulation. Reforestation increased the amount of air exchanged between the valley and the outside during the day, with the largest hourly increase of 10% on calm weather days and a monthly mean hourly increase of 2% for the study period (Dec. 2009). Reforestation affected the spatial distribution of pollutants and slightly improved the urban air quality, especially in the eastern valley. Results from this study provide useful information for future urban air quality management and reforestation plan, and some experience for cities with similar situations in

The California Valley grassland

Science.gov (United States)

Keeley, J.E.; Schoenherr, Allan A.

1990-01-01

Grasslands are distributed throughout California from Oregon to Baja California Norte and from the coast to the desert (Brown 1982) (Figure 1). This review will focus on the dominant formation in cismontane California, a community referred to as Valley Grassland (Munz 1959). Today, Valley Grassland is dominated by non-native annual grasses in genera such as Avena (wild oat), Bromus (brome grass), and Hordeum (barley), and is often referred to as the California annual grassland. On localized sites, native perennial bunchgrasses such as Stipa pultra (purple needle grass) may dominate and such sites are interpreted to be remnants of the pristine valley grassland. In northwestern California a floristically distinct formation of the Valley Grassland, known as Coast Prairie (Munz 1959) or Northern Coastal Grassland (Holland and Keil 1989) is recognized. The dominant grasses include many native perennial bunchgrasses in genera such as Agrostis, Calamagrostis, Danthonia, Deschampsia, Festuca, Koeleria and Poa (Heady et al. 1977). Non-native annuals do not dominate, but on some sites non-native perennials like Anthoxanthum odoratum may colonize the native grassland (Foin and Hektner 1986). Elevationally, California's grasslands extend from sea level to at leas 1500 m. The upper boundary is vague because montane grassland formations are commonly referred to as meadows; a community which Munz (1959) does not recognize. Holland and Keil (1989) describe the montane meadow as an azonal community; that is, a community restricted not so much to a particular climatic zone but rather controlled by substrate characteristics. They consider poor soil-drainage an over-riding factor in the development of montane meadows and, in contrast to grasslands, meadows often remain green through the summer drought. Floristically, meadows are composed of graminoids; Cyperaceae, Juncaceae, and rhizomatous grasses such as Agropyron (wheat grass). Some bunchgrasses, such as Muhlenbergia rigens, are

Subsurface and petroleum geology of the southwestern Santa Clara Valley ("Silicon Valley"), California

Science.gov (United States)

Stanley, Richard G.; Jachens, Robert C.; Lillis, Paul G.; McLaughlin, Robert J.; Kvenvolden, Keith A.; Hostettler, Frances D.; McDougall, Kristin A.; Magoon, Leslie B.

2002-01-01

and 1929 to total depths as great as 840 m. At least one pump unit is still standing. Although no lithologic or paleontologic samples are available from the wells, driller's logs indicate the presence of thick intervals of brown shale and sandstone resembling nearby outcrops of the Miocene Monterey Formation. Small amounts of oil and gas were observed in several wells, but commercial production was never established. Oil from the Peck well in Los Gatos is highly biodegraded, contains biomarkers commonly found in oils derived from the Monterey Formation, and has a stable-C-isotopic (d13C) composition of –23.32 permil, indicating derivation from a Miocene Monterey Formation source rock. Preliminary calculations suggest that about 1 billion barrels of oil may have been generated from source rocks within the Monterey Formation in the deepest part of the subsurface sedimentary basin between Los Gatos and Cupertino. Most of this oil was probably lost to biodegradation, oxidation, and leakage to the surface, but some oil may have accumulated in as-yet-undiscovered structural and stratigraphic traps along the complex structural boundary between the Santa Clara Valley and the Santa Cruz Mountains. Although some of these undiscovered accumulations of oil may be of commercial size, future petroleum exploration is unlikely because most of the area is currently devoted to residential, recreational, commercial, and industrial uses.

Geology, water-quality, hydrology, and geomechanics of the Cuyama Valley groundwater basin, California, 2008--12

Science.gov (United States)

Everett, Rhett; Gibbs, Dennis R.; Hanson, Randall T.; Sweetkind, Donald S.; Brandt, Justin T.; Falk, Sarah E.; Harich, Christopher R.

2013-01-01

To assess the water resources of the Cuyama Valley groundwater basin in Santa Barbara County, California, a series of cooperative studies were undertaken by the U.S. Geological Survey and the Santa Barbara County Water Agency. Between 2008 and 2012, geologic, water-quality, hydrologic and geomechanical data were collected from selected sites throughout the Cuyama Valley groundwater basin. Geologic data were collected from three multiple-well groundwater monitoring sites and included lithologic descriptions of the drill cuttings, borehole geophysical logs, temperature logs, as well as bulk density and sonic velocity measurements of whole-core samples. Generalized lithologic characterization from the monitoring sites indicated the water-bearing units in the subsurface consist of unconsolidated to partly consolidated sand, gravel, silt, clay, and occasional cobbles within alluvial fan and stream deposits. Analysis of geophysical logs indicated alternating layers of finer- and coarser-grained material that range from less than 1 foot to more than 20 feet thick. On the basis of the geologic data collected, the principal water-bearing units beneath the monitoring-well sites were found to be composed of younger alluvium of Holocene age, older alluvium of Pleistocene age, and the Tertiary-Quaternary Morales Formation. At all three sites, the contact between the recent fill and younger alluvium is approximately 20 feet below land surface. Water-quality samples were collected from 12 monitoring wells, 27 domestic and supply wells, 2 springs, and 4 surface-water sites and were analyzed for a variety of constituents that differed by site, but, in general, included trace elements; nutrients; dissolved organic carbon; major and minor ions; silica; total dissolved solids; alkalinity; total arsenic and iron; arsenic, chromium, and iron species; and isotopic tracers, including the stable isotopes of hydrogen and oxygen, activities of tritium, and carbon-14 abundance. Of the 39

Groundwater quality in the Antelope Valley, California

Science.gov (United States)

Dawson, Barbara J. Milby; Belitz, Kenneth

2012-01-01

Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Antelope Valley is one of the study areas being evaluated. The Antelope study area is approximately 1,600 square miles (4,144 square kilometers) and includes the Antelope Valley groundwater basin (California Department of Water Resources, 2003). Antelope Valley has an arid climate and is part of the Mojave Desert. Average annual rainfall is about 6 inches (15 centimeters). The study area has internal drainage, with runoff from the surrounding mountains draining towards dry lakebeds in the lower parts of the valley. Land use in the study area is approximately 68 percent (%) natural (mostly shrubland and grassland), 24% agricultural, and 8% urban. The primary crops are pasture and hay. The largest urban areas are the cities of Palmdale and Lancaster (2010 populations of 152,000 and 156,000, respectively). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. The primary aquifers in Antelope Valley are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in Antelope Valley are completed to depths between 360 and 700 feet (110 to 213 meters), consist of solid casing from the land surface to a depth of 180 to 350 feet (55 to 107 meters), and are screened or perforated below the solid casing. Recharge to the groundwater system is primarily runoff from the surrounding mountains, and by direct infiltration of irrigation and sewer and septic

Effect of ion irradiation on the structure and the surface topography of carbon fiber

International Nuclear Information System (INIS)

Ligacheva, E.A.; Galyaeva, L.V.; Gavrilov, N.V.; Belykh, T.A.; Ligachev, A.E.; Sokhoreva, V.V.

2006-01-01

The effect of C + ion irradiation (40 keV, 10 15 - 10 19 cm -2 ) on the structure and surface topography of high-module carbon fibers is investigated. Interplanar distance and internal stress values are found to be minimal at a radiation dose of 10 17 cm -2 , the height of a layer pack being practically unchanged. The relief of ion irradiated carbon fiber surface constitutes regularly repetitive valleys and ridges spaced parallel with the fiber axis [ru

The Health Valley: Global Entrepreneurial Dynamics.

Science.gov (United States)

Dubuis, Benoit

2014-12-01

In the space of a decade, the Lake Geneva region has become the Health Valley, a world-class laboratory for discovering and developing healthcare of the future. Through visionary individuals and thanks to exceptional infrastructure this region has become one of the most dynamic in the field of innovation, including leading scientific research and exceptional actors for the commercialization of academic innovation to industrial applications that will improve the lives of patients and their families. Here follows the chronicle of a spectacular expansion into the Health Valley.

Solar energy innovation and Silicon Valley

Science.gov (United States)

Kammen, Daniel M.

2015-03-01

The growth of the U. S. and global solar energy industry depends on a strong relationship between science and engineering innovation, manufacturing, and cycles of policy design and advancement. The mixture of the academic and industrial engine of innovation that is Silicon Valley, and the strong suite of environmental policies for which California is a leader work together to both drive the solar energy industry, and keep Silicon Valley competitive as China, Europe and other area of solar energy strength continue to build their clean energy sectors.

Phallodrilus hallae, a new tubificid oligochaete from the St. Lawrence Great Lakes

Science.gov (United States)

Cook, David G.; Hiltunen, Jarl K.

1975-01-01

The predominantly marine tubificid genus Phallodrilus is defined, a key to its nine species constructed, and an illustrated description of Phallodrilus hallae n. sp. from the St. Lawrence Great Lakes presented. The species is distinguished from other members of the genus by its well-developed atrial musculature, extensions of which ensheath the posterior prostatic ducts.Phallodrilus hallae n. sp. is a small worm which is widely distributed in the sublittoral and profundal benthos of Lake Superior; lakewide it occurred in mean densities of 50 individuals per square metre. Available records indicate a more restricted distribution in Lake Huron and Georgian Bay. We suggest that P. hallae n. sp. is either a glaciomarine relict species, or that it entered the Great Lakes system at the time of the marine transgression of the St. Lawrence valley. The apparent restriction of P. hallae n. sp. to waters of high quality suggests that it may be a sensitive oligotrophic indicator species.

A Mackenzie Valley Pipeline -- Getting the challenge into perspective

Energy Technology Data Exchange (ETDEWEB)

Cournoyea, N. J. [Iuvialuit Regional Corporation, Yellowknife, NT (Canada)

2000-07-01

Another perspective on a Mackenzie Valley pipeline is given by a former Premier and Minister of Energy, Mines and Petroleum Resources of the NWT. The author views a Mackenzie Valley Pipeline that would carry both American and Canadian natural gas down the Valley as the one that would offer Canada the largest return in terms of employment, income and fiscal benefits. It is her view that if the Alaska Highway pipeline were to be developed first, it would be much more difficult to link up Canadian gas later, and the loss of the estimated 70 Tcf of Canadian gas reserves would be catastrophic not only to resource owners, but to the public interest at large, since without this Canadian gas, other fuel sources would have to be used to meet the demand for energy, thereby increasing the production of carbon dioxide and added risk of accelerating global warming. This, of course, is in addition to the lost opportunity available to the Inuvialuit and other northern aboriginal people to set a course of economic development that would enable aboriginal people of the north to become full and equal participants in the northern and Canadian economies. It is an opportunity that can be realized only if all stakeholders meet the challenges and take their respective responsibilities seriously. This means action by the federal government to support and encourage the development of Canadian frontier gas, to put in place a fair and workable regulatory process, to help aboriginal people achieve a durable and fair share in the benefits of development, to ensure the protection of the environment and realize the goals of sustainable development. Industry and aboriginal leaders too, must show leadership by forging a genuine and effective partnership, and all stakeholders must cooperate to make Canadian frontier gas and pipeline development an example to the world of what sustainable development should and could be. Industry must also keep a perspective on the regulatory hurdles, on the

Biogeochemical studies of wintering waterfowl in the Imperial and Sacramento Valleys

Energy Technology Data Exchange (ETDEWEB)

Koranda, J.J.; Stuart, M.; Thompson, S.; Conrado, C.

1979-10-01

Trace and major elemental composition were determined in the organs of wintering waterfowl in the Imperial and Sacramento Valleys of California, and in soils, sediments, and agricultural fertilizer that constitute the various sources of elements in the waterfowl. These data provide a biogeochemical baseline for waterfowl populations wintering in an area being developed for geothermal power. This baseline in the Imperial Valley is affected by soil and sediment composition, agricultural effluents in irrigation and stream water, and spent shot deposited by hunters in waterfowl habitats. The waterfowl acquire a set of trace elements from these sources and concentrations increase in their organs over the wintering period. Nickel, arsenic, selenium, bromine, and lead are the primary elements acquired from soil sources, agricultural effluents, and spent shot in the Imperial Valley. The assessment of effects from geothermal effluents on waterfowl populations in complex because there are large influxes of materials into the Imperial Valley ecosystem that contain trace elements, i.e., irrigation water, phosphatic fertilizers, pesticides, and lead shot. Multiple sources exist for many elements prominent in the expected geothermal effluents. The relationships between the two California valleys, the Imperial and Sacramento, are apparent in the trace element concentrations in the organs of waterfowl obtained in those two valleys. Arsenic is absent in the waterfowl organs obtained in the Sacramento Valley and relatively common in the Imperial Valley waterfowl. The effect of any release of geothermal effluent in the Imperial Valley waterfowl habitats will be difficult to describe because of the complexity of the biogeochemical baseline and the multiple sources of trace and major elements in the ecosystem.

Goldstone-Apple Valley Radio Telescope System Theory of Operation

Science.gov (United States)

Stephan, George R.

1997-01-01

The purpose of this learning module is to enable learners to describe how the Goldstone-Apple Valley Radio Telescope (GAVRT) system functions in support of Apple Valley Science and Technology Center's (AVSTC) client schools' radio astronomy activities.

Summary of the engineering assessment of inactive uranium mill tailings: Monument Valley site, Monument Valley, Arizona

International Nuclear Information System (INIS)

1981-10-01

Ford, Bacon and Davis Utah Inc. has reevaluated the Monument Valley site in order to revise the March 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Monument Valley, Arizona. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 1.1 million tons of tailings at the Monument Valley site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors. The four alternative actions presented in this engineering assessment range from millsite decontamination with the addition of 3 m of stabilization cover material to removal of the tailings to remote disposal sites and decontamination of the tailings site. Cost estimates for the four options range from about $6,600,000 for stabilization in-place, to about $15,900,000 for disposal at a distance of about 15 mi. Three principal alternatives for reprocessing the Monument Valley tailings were examined: heap leaching, treatment at an existing mill; and reprocessing at a new conventional mill constructed for tailings reprocessing. The cost of the uranium recovered would be more than $500/lb of U 3 O 8 by heap leach or conventional plant processes. The spot market price for uranium was $25/lb early in 1981. Therefore, reprocessing the tailings for uranium recovery is economically unattractive

A model of late quaternary landscape development in the Delaware Valley, New Jersey and Pennsylvania

Science.gov (United States)

Ridge, J.C.; Evenson, E.B.; Sevon, W.D.

1992-01-01

In the Delaware Valley of New Jersey and eastern Pennsylvania the late Quaternary history of colluviation, fluvial adjustment, and soil formation is based on the ages of pre-Wisconsinan soils and glacial deposits which are indicated by feld relationships and inferred from mid-latitude climate changes indicated by marine oxygen-isotope records. The area is divided into four terranes characterized by sandstone, gneiss, slate and carbonate rocks. Since the last pre-Wisconsinan glaciation (> 130 ka, inferred to be late Illinoian), each terrane responded differently to chemical and mechanical weathering. During the Sangamon interglacial stage (??? 130-75 ka) in situ weathering is inferred to have occurred at rates greater than transportation of material which resulted in the formation of deep, highly weathered soil and saprolite, and dissolution of carbonate rocks. Cold climatic conditions during the Wisconsinan, on the other hand, induced erosion of the landscape at rates faster than soil development. Upland erosion during the Wisconsinan removed pre-Wisconsinan soil and glacial sediment and bedrock to produce muddy to blocky colluvium, gre??zes lite??es, and alluvial fans on footslopes. Fluvial gravel and overlying colluvium in the Delaware Valley, both buried by late Wisconsinan outwash, are inferred to represent episodes of early and middle Wisconsinan (??? 75-25 ka) upland erosion and river aggradiation followed by river degradation and colluvium deposition. Early-middle Wisconsinan colluvium is more voluminous than later colluvium despite colder, possibly permafrost conditions during the late Wisconsinan ??? 25-10 ka). Extensive colluviation during the early and middle Wisconsinan resulted from a longer (50 kyr), generally cold interval of erosion with a greater availability of easily eroded pre-Wisconsinan surficial materials on uplands than during the late Wisconsinan. After recession of late Wisconsinan ice from its terminal position, soil formation and

Topographic evolution of Yosemite Valley from Low Temperature Thermochronology

Science.gov (United States)

Tripathy-Lang, A.; Shuster, D. L.; Cuffey, K. M.; Fox, M.

2014-12-01

In this contribution, we interrogate the timing of km-scale topography development in the region around Yosemite Valley, California. Our goal is to determine when this spectacular glacial valley was carved, and how this might help address controversy surrounding the topographic evolution of the Sierra Nevada. At the scale of the range, two rival hypotheses are each supported by different datasets. Low-temperature thermochronology supports the idea that the range has been high-standing since the Cretaceous, whereas geomorphic evidence suggests that much of the elevation of the Sierra Nevada was attained during the Pliocene. Recent work by McPhillips and Brandon (2012) suggests instead that both ideas are valid, with the range losing much elevation during the Cenozoic, but regaining it during Miocene surface uplift.At the local scale, the classic study of Matthes (1930) determined that most of Yosemite Valley was excavated by the Sherwin-age glaciation that ended ~1 Ma. The consensus view is in agreement, although some argue that nearby comparable valleys comparable were carved long ago (e.g., House et al., 1998). If the Quaternary and younger glaciations were responsible for the bulk of the valley's >1 km depth, we might expect apatite (U-Th)/He ages at the valley floor to be histories at these locations, these data constrain patterns of valley topography development through time. We also supplement these data with zircon 4He/3He thermochronometry, which is a newly developed method that provides information on continuous cooling paths through ~120-220 °C. We will present both the apatite and zircon 4He/3He data and, in conjunction with thermo-kinematic modeling, discuss the ability and limitations of these data to test models of Sierra Nevada topography development through time. Matthes (1930) USGS Professional Paper House et al. (1998) Nature McPhillips and Brandon (2012) American Journal of Science

Optimal decentralized valley-filling charging strategy for electric vehicles

International Nuclear Information System (INIS)

Zhang, Kangkang; Xu, Liangfei; Ouyang, Minggao; Wang, Hewu; Lu, Languang; Li, Jianqiu; Li, Zhe

2014-01-01

Highlights: • An implementable charging strategy is developed for electric vehicles connected to a grid. • A two-dimensional pricing scheme is proposed to coordinate charging behaviors. • The strategy effectively works in decentralized way but achieves the systematic valley filling. • The strategy allows device-level charging autonomy, and does not require a bidirectional communication/control network. • The strategy can self-correct when confronted with adverse factors. - Abstract: Uncoordinated charging load of electric vehicles (EVs) increases the peak load of the power grid, thereby increasing the cost of electricity generation. The valley-filling charging scenario offers a cheaper alternative. This study proposes a novel decentralized valley-filling charging strategy, in which a day-ahead pricing scheme is designed by solving a minimum-cost optimization problem. The pricing scheme can be broadcasted to EV owners, and the individual charging behaviors can be indirectly coordinated. EV owners respond to the pricing scheme by autonomously optimizing their individual charge patterns. This device-level response induces a valley-filling effect in the grid at the system level. The proposed strategy offers three advantages: coordination (by the valley-filling effect), practicality (no requirement for a bidirectional communication/control network between the grid and EV owners), and autonomy (user control of EV charge patterns). The proposed strategy is validated in simulations of typical scenarios in Beijing, China. According to the results, the strategy (1) effectively achieves the valley-filling charging effect at 28% less generation cost than the uncoordinated charging strategy, (2) is robust to several potential affecters of the valley-filling effect, such as (system-level) inaccurate parameter estimation and (device-level) response capability and willingness (which cause less than 2% deviation in the minimal generation cost), and (3) is compatible with

Geothermal resource assessment of western San Luis Valley, Colorado

Energy Technology Data Exchange (ETDEWEB)

Zacharakis, Ted G.; Pearl, Richard Howard; Ringrose, Charles D.

1983-01-01

The Colorado Geological Survey initiated and carried out a fully integrated assessment program of the geothermal resource potential of the western San Luis Valley during 1979 and 1980. The San Luis Valley is a large intermontane basin located in southcentral Colorado. While thermal springs and wells are found throughout the Valley, the only thermal waters found along the western part of the Valley are found at Shaw Warm Springs which is a relatively unused spring located approximately 6 miles (9.66 km) north of Del Norte, Colorado. The waters at Shaws Warm Spring have a temperature of 86 F (30 C), a discharge of 40 gallons per minute and contain approximately 408 mg/l of total dissolved solids. The assessment program carried out din the western San Luis Valley consisted of: soil mercury geochemical surveys; geothermal gradient drilling; and dipole-dipole electrical resistivity traverses, Schlumberger soundings, Audio-magnetotelluric surveys, telluric surveys, and time-domain electro-magnetic soundings and seismic surveys. Shaw Warm Springs appears to be the only source of thermal waters along the western side of the Valley. From the various investigations conducted the springs appear to be fault controlled and is very limited in extent. Based on best evidence presently available estimates are presented on the size and extent of Shaw Warm Springs thermal system. It is estimated that this could have an areal extent of 0.63 sq. miles (1.62 sq. km) and contain 0.0148 Q's of heat energy.

Valley-controlled propagation of pseudospin states in bulk metacrystal waveguides

Science.gov (United States)

Chen, Xiao-Dong; Deng, Wei-Min; Lu, Jin-Cheng; Dong, Jian-Wen

2018-05-01

Light manipulations such as spin-direction locking propagation, robust transport, quantum teleportation, and reconfigurable electromagnetic pathways have been investigated at the boundaries of photonic systems. Recently by breaking Dirac cones in time-reversal-invariant photonic crystals, valley-pseudospin coupled edge states have been employed to realize selective propagation of light. Here, we realize the controllable propagation of pseudospin states in three-dimensional bulk metacrystal waveguides by valley degree of freedom. Reconfigurable photonic valley Hall effect is achieved for frequency-direction locking propagation in such a way that the propagation path can be tunable precisely by scanning the working frequency. A complete transition diagram is illustrated on the valley-dependent pseudospin states of Dirac-cone-absent photonic bands. A photonic blocker is proposed by cascading two inversion asymmetric metacrystal waveguides in which pseudospin-direction locking propagation exists. In addition, valley-dependent pseudospin bands are also discussed in a realistic metamaterials sample. These results show an alternative way toward molding the pseudospin flow in photonic systems.

Valley-symmetric quasi-1D transport in ballistic graphene

Science.gov (United States)

Lee, Hu-Jong

We present our recent studies on gate-defined valley-symmetric one-dimensional (1D) carrier guiding in ballistic monolayer graphene and valley-symmetry-protected topological 1D transport in ballistic bilayer graphene. Successful carrier guiding was realized in ballistic monolayer graphene even in the absence of a band gap by inducing a high distinction ( more than two orders of magnitude) in the carrier density between the region of a quasi-1D channel and the rest of the top-gated regions. Conductance of a channel shows quantized values in units of 4e2/ h, suggesting that the valley symmetry is preserved. For the latter, the topological 1D conduction was realized between two closely arranged insulating regions with inverted band gaps, induced under a pair of split dual gating with polarities opposite to each other. The maximum conductance along the boundary channel showed 4e2/ h, again with the preserved valley symmetry. The 1D topological carrier guiding demonstrated in this study affords a promising route to robust valleytronic applications and sophisticated valley-associated functionalities based on 2D materials. This work was funded by the National Research Foundation of Korea.

Geohydrology and Water Quality of the Valley-Fill Aquifer System in the Upper Sixmile Creek and West Branch Owego Creek Valleys in the Town of Caroline, Tompkins County, New York

Science.gov (United States)

Miller, Todd S.

2009-01-01

In 2002, the U.S. Geological Survey, in cooperation with the Town of Caroline and Tompkins County Planning Department, began a study of the valley-fill aquifer system in upper Sixmile Creek and headwaters of West Branch Owego Creek valleys in the Town of Caroline, NY. The purpose of the study is to provide geohydrologic data to county and town planners as they develop a strategy to manage and protect their water resources. The first aquifer reach investigated in this series is in the Town of Caroline and includes the upper Sixmile Creek valley and part of West Branch Owego Creek valley. The portions of the valley-fill aquifer system that are comprised of saturated coarse-grained sediments including medium to coarse sand and sandy gravel form the major aquifers. Confined sand and gravel units form the major aquifers in the western and central portions of the upper Sixmile Creek valley, and an unconfined sand and gravel unit forms the major aquifer in the eastern portion of the upper Sixmile Creek valley and in the headwaters of the West Branch Owego Creek valley. The valley-fill deposits are thinnest near the edges of the valley where they pinch out along the till-mantled bedrock valley walls. The thickness of the valley fill in the deepest part of the valley, at the western end of the study area, is about 100 feet (ft); the thickness is greater than 165 ft on top of the Valley Heads Moraine in the central part of the valley. An estimated 750 people live over and rely on groundwater from the valley-fill aquifers in upper Sixmile Creek and West Branch Owego Creek valleys. Most groundwater withdrawn from the valley-fill aquifers is pumped from wells with open-ended 6-inch diameter casings; the remaining withdrawals are from shallow dug wells or cisterns that collect groundwater that discharges to springs (especially in the Brooktondale area). The valley-fill aquifers are the sources of water for about 200 households, several apartment complexes, two mobile home parks

Role of Biotic and Abiotic Processes on Soil CO2 Dynamics in the McMurdo Dry Valleys, Antarctica

Science.gov (United States)

Risk, D. A.; Macintyre, C. M.; Lee, C.; Cary, C.; Shanhun, F.; Almond, P. C.

2016-12-01

In the harsh conditions of the Antarctic Dry Valleys, microbial activity has been recorded via measurements of soil carbon dioxide (CO2) concentration and surface efflux. However, high temporal resolution studies in the Dry Valleys have also shown that abiotic solubility-driven processes can strongly influence (and perhaps even dominate) the CO2 dynamics in these low flux environments and suggests that biological activity may be lower than previously thought. In this study, we aim to improve our understanding of CO2 dynamics (biotic and abiotic) in Antarctic Dry Valley soils using long-term automated measurements of soil CO2 surface flux and soil profile concentration at several sites, often at sub-diel frequency. We hypothesize that soil CO2 variations are driven primarily by environmental factors affecting CO2 solubility in soil solution, mainly temperature, and that these processes may even overprint biologic production in representative Dry Valley soils. Monitoring of all sites revealed only one likely biotic CO2 production event, lasting three weeks during the Austral summer and reaching fluxes of 0.4 µmol/m2/s. Under more typical low flux conditions (sampling campaigns. Subsurface CO2 monitoring and a lab-controlled Antarctic soil simulation experiment confirmed that abiotic processes are capable of dominating soil CO2 variability. Diel temperature cycles crossing the freezing boundary revealed a dual abiotic cycle of solubility cycling and gas exclusion from ice formation observed only by high temporal frequency measurements (30 min). This work demonstrates a need for a numerical model to partition the dynamic abiotic processes underlying any biotic CO2 production in order to understand potential climate-change induced increases in microbial productivity in terrestrial Antarctica.

Black Mats, Spring-Fed Streams, and Late-Glacial-Age Recharge in the Southern Great Basin

Science.gov (United States)

Quade, Jay; Forester, R.M.; Pratt, W.L.; Carter, C.

1998-01-01

Black mats are prominent features of the late Pleistocene and Holocene stratigraphic record in the southern Great Basin. Faunal, geochemical, and sedimentological evidence shows that the black mats formed in several microenvironments related to spring discharge, ranging from wet meadows to shallow ponds. Small land snails such as Gastrocopta tappaniana and Vertigo berryi are the most common mollusk taxa present. Semiaquatic and aquatic taxa are less abundant and include Catinellids, Fossaria parva, Gyraulus parvus, and others living today in and around perennial seeps and ponds. The ostracodes Cypridopsis okeechobi and Scottia tumida, typical of seeps and low-discharge springs today, as well as other taxa typical of springs and wetlands, are common in the black mats. Several new species that lived in the saturated subsurface also are present, but lacustrine ostracodes are absent. The ??13C values of organic matter in the black mats range from -12 to -26???, reflecting contributions of tissue from both C3 (sedges, most shrubs and trees) and C4 (saltbush, saltgrass) plants. Carbon-14 dates on the humate fraction of 55 black mats fall between 11,800 to 6300 and 2300 14C yr B.P. to modern. The total absence of mats in our sample between 6300 and 2300 14C yr B.P. likely reflects increased aridity associated with the mid-Holocene Altithermal. The oldest black mats date to 11,800-11,600 14C yr B.P., and the peak in the 14C black mat distribution falls at ???10,000 14C yr B.P. As the formation of black mats is spring related, their abundance reflects refilling of valley aquifers starting no later than 11,800 and peaking after 11,000 14C yrB.P. Reactivation of spring-fed channels shortly before 11,200 14C yr B.P. is also apparent in the stratigraphic records from the Las Vegas and Pahrump Valleys. This age distribution suggests that black mats and related spring-fed channels in part may have formed in response to Younger Dryas (YD)-age recharge in the region. However, the

Valley-dependent spin-orbit torques in two-dimensional hexagonal crystals

KAUST Repository

Li, Hang; Wang, Xuhui; Manchon, Aurelien

2016-01-01

We study spin-orbit torques in two-dimensional hexagonal crystals such as graphene, silicene, germanene, and stanene. The torque possesses two components, a fieldlike term due to inverse spin galvanic effect and an antidamping torque originating from Berry curvature in mixed spin-k space. In the presence of staggered potential and exchange field, the valley degeneracy can be lifted and we obtain a valley-dependent Berry curvature, leading to a tunable antidamping torque by controlling the valley degree of freedom. The valley imbalance can be as high as 100% by tuning the bias voltage or magnetization angle. These findings open new venues for the development of current-driven spin-orbit torques by structural design.

Valley-dependent spin-orbit torques in two-dimensional hexagonal crystals

KAUST Repository

Li, Hang

2016-01-11

We study spin-orbit torques in two-dimensional hexagonal crystals such as graphene, silicene, germanene, and stanene. The torque possesses two components, a fieldlike term due to inverse spin galvanic effect and an antidamping torque originating from Berry curvature in mixed spin-k space. In the presence of staggered potential and exchange field, the valley degeneracy can be lifted and we obtain a valley-dependent Berry curvature, leading to a tunable antidamping torque by controlling the valley degree of freedom. The valley imbalance can be as high as 100% by tuning the bias voltage or magnetization angle. These findings open new venues for the development of current-driven spin-orbit torques by structural design.

Effect of faulting on ground-water movement in the Death Valley region, Nevada and California

International Nuclear Information System (INIS)

Faunt, C.C.

1997-01-01

This study characterizes the hydrogeologic system of the Death Valley region, an area covering approximately 100,000 square kilometers. The study also characterizes the effects of faults on ground-water movement in the Death Valley region by synthesizing crustal stress, fracture mechanics,a nd structural geologic data. The geologic conditions are typical of the Basin and Range Province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. Faulting and associated fracturing is pervasive and greatly affects ground-water flow patterns. Faults may become preferred conduits or barriers to flow depending on whether they are in relative tension, compression, or shear and other factors such as the degree of dislocations of geologic units caused by faulting, the rock types involved, the fault zone materials, and the depth below the surface. The current crustal stress field was combined with fault orientations to predict potential effects of faults on the regional ground-water flow regime. Numerous examples of fault-controlled ground-water flow exist within the study area. Hydrologic data provided an independent method for checking some of the assumptions concerning preferential flow paths. 97 refs., 20 figs., 5 tabs

Determination of trace uranium in atmospheric precipitation of the Xiangjiang river valley by fission track method

International Nuclear Information System (INIS)

Zhai Pengji; Kang Tiesheng

1986-01-01

In this work the uranium contents in atmospheric precipitations in the region of the Xiangjiang River valley have been measured by fission track method, which range from 0.008 to 1.5 ppb. The majority of them are below 0.1 ppb. The uranium contents in the samples form different geographical positions are obviously different. Sometimes the differences in uranium contents of the samples from the same area collected at different times are also great. A preliminary discussion is given on the sources of uranium in atmospheric precipitation and on the reason of the difference in contents

West Valley Demonstration Project, West Valley, New York: Annual report

International Nuclear Information System (INIS)

1989-01-01

Under the West Valley Demonstration Project Act, Public Law 96-368, liquid high-level radioactive waste stored at the Western New York Nuclear Services Center, West Valley, New York, that resulted from spent nuclear fuel reprocessing operations conducted between 1966 and 1972, is to be solidified in borosilicate glass and transported to a federal repository for geologic disposal. A major milestone was reached in May 1988 when the Project began reducing the volume of the liquid high-level waste. By the end of 1988, approximately 15 percent of the initial inventory had been processed into two waste streams. The decontaminated low-level liquid waste is being solidified in cement. The high-level waste stream is being stored in an underground tank pending its incorporation into borosilicate glass. Four tests of the waste glass melter system were completed. These tests confirmed equipment operability, control system reliability, and provided samples of waste glass for durability testing. In mid-1988, the Department validated an integrated cost and schedule plan for activities required to complete the production of the waste borosilicate glass. Design of the radioactive Vitrification Facility continued

Selection of a carbon-14 fixation form

International Nuclear Information System (INIS)

Scheele, R.D.; Burger, L.L.

1982-09-01

This report summarizes work on the selection of a disposal form for carbon-14 produced during the production of nuclear power. Carbon compounds were screened on the basis of solubility, thermal stability, resistance to oxidation, cost and availability, compatibility with the selected disposal matrix, leach resistance when incorporated in concrete, and compatibility with capture technologies. Carbonates are the products of the various technologies presently considered for carbon-14 capture. The alkaline earth carbonates exhibit the greatest thermal stabilities, lowest solubilities, lowest raw material cost, and greatest raw material availabilities. When reactions with cement and its impurities are considered, calcium and strontium carbonates are the only alkaline earth carbonates resistant to hydrolysis and reaction with sulfate. Leaching tests of barium, calcium, lead, potassium, and strontium carbonates in concrete showed calcium carbonate concrete to be slightly superior to the other alkaline earth carbonates, and greatly superior to a soluble carbonate, potassium carbonate, and lead carbonate. None of the additives to the concrete reduced the carbonate leaching. Acidic CO 2 -containing waters were found to greatly increase carbonate leaching from concrete. Sea water was found to leach less carbon from carbonate concretes than either distilled water or Columbia River water, which showed nearly equivalent leaching. Based on our work, calcium, barium, and strontium carbonates in concrete are the most suitable waste forms for carbon-14, with calcium carbonate concrete slightly superior to the others. If the waste form is to be exposed to natural waters, sea water will have the lowest leach rate. 6 figures, 7 tables

Medicinal plants of Usherai valley, Dir, NWFP, Pakistan

International Nuclear Information System (INIS)

Hazarat, A.; Shah, J.; Ahmad, S.; Nasir, M.; Jan, A.K.; Skindar

2010-01-01

This research is based on the results of an ethno-botanical research conducted in Usherai Valley. The main objective was to enlist the wealth of medicinal plants. In total 50 species, belonging to 32 families of wild herbs, shrubs and trees were found to be used as medicinal plants by the inhabitants in the valley. (author)

AIR POLLUTION FEATURES OF THE VALLEY-BASED TOWNS IN HUNGARY

Directory of Open Access Journals (Sweden)

Z. UTASI

2016-03-01

Full Text Available There are 30 valley-based towns with >10,000 inhabitants in Hungary, filled by 1.023 million people i.e. 10 % of the population. Two criteria are used to define the valley-based town. They are: (i Vertical difference between the lowest point in the town and the highest one around it should be >100 m. At the same time, (ii the same difference on the opposite side should be >50 m. Air pollution data by the National Air Pollution Observation Network are used. Five contaminants were selected and analysed for 2007, 2010 and 2013. Due to a sharp reduction in the network, we could find data for a small part of the valley-based towns. Control towns with equal air-quality observations and similar cumulative number of inhabitants were also selected. The contaminants and the number of the settlements are: NO2 manual (14 valley-based vs. 2x14 control, NO2 automatic (8 vs. 8, SO2 automatic (7 vs. 2x6, PM10 automatic (8 vs. 2x7 and PM10 deposition manual (6 vs. 8. Average values, as well as high concentration episodes (>98%thresholds are equally analysed and evaluated. The main conclusion is that there are so big differences between the years both in absolute values and relative sequence of valley-based and control groups that the analysed there years is not enough to make any final conclusion. For step-over frequencies, however valley-based towns have some advantage, possibly due to the valley-hill wind system.

The Ohio River Valley CO2 Storage Project AEP Mountaineer Plan, West Virginia

Energy Technology Data Exchange (ETDEWEB)

Neeraj Gupta

2009-01-07

This report includes an evaluation of deep rock formations with the objective of providing practical maps, data, and some of the issues considered for carbon dioxide (CO{sub 2}) storage projects in the Ohio River Valley. Injection and storage of CO{sub 2} into deep rock formations represents a feasible option for reducing greenhouse gas emissions from coal-burning power plants concentrated along the Ohio River Valley area. This study is sponsored by the U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL), American Electric Power (AEP), BP, Ohio Coal Development Office, Schlumberger, and Battelle along with its Pacific Northwest Division. An extensive program of drilling, sampling, and testing of a deep well combined with a seismic survey was used to characterize the local and regional geologic features at AEP's 1300-megawatt (MW) Mountaineer Power Plant. Site characterization information has been used as part of a systematic design feasibility assessment for a first-of-a-kind integrated capture and storage facility at an existing coal-fired power plant in the Ohio River Valley region--an area with a large concentration of power plants and other emission sources. Subsurface characterization data have been used for reservoir simulations and to support the review of the issues relating to injection, monitoring, strategy, risk assessment, and regulatory permitting. The high-sulfur coal samples from the region have been tested in a capture test facility to evaluate and optimize basic design for a small-scale capture system and eventually to prepare a detailed design for a capture, local transport, and injection facility. The Ohio River Valley CO{sub 2} Storage Project was conducted in phases with the ultimate objectives of demonstrating both the technical aspects of CO{sub 2} storage and the testing, logistical, regulatory, and outreach issues related to conducting such a project at a large point source under realistic constraints. The site

Debris Flow Occurrence and Sediment Persistence, Upper Colorado River Valley, CO.

Science.gov (United States)

Grimsley, K J; Rathburn, S L; Friedman, J M; Mangano, J F

2016-07-01

Debris flow magnitudes and frequencies are compared across the Upper Colorado River valley to assess influences on debris flow occurrence and to evaluate valley geometry effects on sediment persistence. Dendrochronology, field mapping, and aerial photographic analysis are used to evaluate whether a 19th century earthen, water-conveyance ditch has altered the regime of debris flow occurrence in the Colorado River headwaters. Identifying any shifts in disturbance processes or changes in magnitudes and frequencies of occurrence is fundamental to establishing the historical range of variability (HRV) at the site. We found no substantial difference in frequency of debris flows cataloged at eleven sites of deposition between the east (8) and west (11) sides of the Colorado River valley over the last century, but four of the five largest debris flows originated on the west side of the valley in association with the earthen ditch, while the fifth is on a steep hillslope of hydrothermally altered rock on the east side. These results suggest that the ditch has altered the regime of debris flow activity in the Colorado River headwaters as compared to HRV by increasing the frequency of debris flows large enough to reach the Colorado River valley. Valley confinement is a dominant control on response to debris flows, influencing volumes of aggradation and persistence of debris flow deposits. Large, frequent debris flows, exceeding HRV, create persistent effects due to valley geometry and geomorphic setting conducive to sediment storage that are easily delineated by valley confinement ratios which are useful to land managers.

Functional Carbon Nanotube/Mesoporous Carbon/MnO2 Hybrid Network for High-Performance Supercapacitors

Directory of Open Access Journals (Sweden)

Tao Tao

2014-01-01

Full Text Available A functional carbon nanotube/mesoporous carbon/MnO2 hybrid network has been developed successfully through a facile route. The resulting composites exhibited a high specific capacitance of 351 F/g at 1 A g−1, with intriguing charge/discharge rate performance and cycling stability due to a synergistic combination of large surface area and excellent electron-transport capabilities of MnO2 with the good conductivity of the carbon nanotube/mesoporous carbon networks. Such composite shows great potential to be used as electrodes for supercapacitors.

Enhanced rice production but greatly reduced carbon emission following biochar amendment in a metal-polluted rice paddy.

Science.gov (United States)

Zhang, Afeng; Bian, Rongjun; Li, Lianqing; Wang, Xudong; Zhao, Ying; Hussain, Qaiser; Pan, Genxing

2015-12-01

Soil amendment of biochar (BSA) had been shown effective for mitigating greenhouse gas (GHG) emission and alleviating metal stress to plants and microbes in soil. It has not yet been addressed if biochar exerts synergy effects on crop production, GHG emission, and microbial activity in metal-polluted soils. In a field experiment, biochar was amended at sequential rates at 0, 10, 20, and 40 t ha(-1), respectively, in a cadmium- and lead-contaminated rice paddy from the Tai lake Plain, China, before rice cropping in 2010. Fluxes of soil carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) were monitored using a static chamber method during the whole rice growing season (WRGS) of 2011. BSA significantly reduced soil CaCl2 extractable pool of Cd, and DTPA extractable pool of Cd and Pb. As compared to control, soil CO2 emission under BSA was observed to have no change at 10 t ha(-1) but decreased by 16-24% at 20 and 40 t ha(-1). In a similar trend, BSA at 20 and 40 t ha(-1) increased rice yield by 25-26% and thus enhanced ecosystem CO2 sequestration by 47-55% over the control. Seasonal total N2O emission was reduced by 7.1, 30.7, and 48.6% under BSA at 10, 20, and 40 t ha(-1), respectively. Overall, a net reduction in greenhouse gas balance (NGHGB) by 53.9-62.8% and in greenhouse gas intensity (GHGI) by 14.3-28.6% was observed following BSA at 20 and 40 t ha(-1). The present study suggested a great potential of biochar to enhancing grain yield while reducing carbon emission in metal-polluted rice paddies.

Groundwater quality in the Owens Valley, California

Science.gov (United States)

Dawson, Barbara J. Milby; Belitz, Kenneth

2012-01-01

Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Owens Valley is one of the study areas being evaluated. The Owens study area is approximately 1,030 square miles (2,668 square kilometers) and includes the Owens Valley groundwater basin (California Department of Water Resources, 2003). Owens Valley has a semiarid to arid climate, with average annual rainfall of about 6 inches (15 centimeters). The study area has internal drainage, with runoff primarily from the Sierra Nevada draining east to the Owens River, which flows south to Owens Lake dry lakebed at the southern end of the valley. Beginning in the early 1900s, the City of Los Angeles began diverting the flow of the Owens River to the Los Angeles Aqueduct, resulting in the evaporation of Owens Lake and the formation of the current Owens Lake dry lakebed. Land use in the study area is approximately 94 percent (%) natural, 5% agricultural, and 1% urban. The primary natural land cover is shrubland. The largest urban area is the city of Bishop (2010 population of 4,000). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. Recharge to the groundwater system is primarily runoff from the Sierra Nevada, and by direct infiltration of irrigation. The primary sources of discharge are pumping wells, evapotranspiration, and underflow to the Owens Lake dry lakebed. The primary aquifers in Owens Valley are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database

Ground water in Fountain and Jimmy Camp Valleys, El Paso County, Colorado with a section on Computations of drawdowns caused by the pumping of wells in Fountain Valley

Science.gov (United States)

Jenkins, Edward D.; Glover, Robert E.

1964-01-01

The part of Fountain Valley considered in this report extends from Colorado Springs to the Pueblo County line. It is 23 miles long and has an area of 26 square miles. The part of Jimmy Camp Valley discussed is 11 miles long and has an area of 9 square miles. The topography is characterized by level flood plains and alluvial terraces that parallel the valley and by rather steep hills along the valley sides. The climate is semiarid, average annual precipitation being about 13 inches. Farming and stock raising are the principal occupations in the valleys; however, some of the agricultural land near Colorado Springs is being used for housing developments. The Pierre Shale and alluvium underlie most of the area, and mesa gravel caps the shale hills adjacent to Fountain Valley. The alluvium yields water to domestic, stock, irrigation, and public-supply wells and is capable of yielding large quantities of water for intermittent periods. Several springs issue along the sides of the valley at the contact of the mesa gravel and the underlying Pierre Shale. The water table ranges in depth from less than 10 feet along the bottom lands to about 80 feet along the sides of the valleys; the saturated thickness ranges from less than a foot to about 50 feet. The ground-water reservoir in Fountain Valley is recharged by precipitation that falls within the area, by percolation from Fountain Creek, which originates in the Pikes Peak, Monument Valley, and Rampart Range areas, and by seepage from irrigation water. This reservoir contains about 70,000 acre-feet of ground water in storage. The ground-water reservoir in Jimmy Camp Valley is recharged from precipitation that falls within the area, by percolation from Jimmy Camp Creek during periods of streamflow, and by seepage from irrigation water. The Jimmy Camp ground-water reservoir contains about 25,000 acre-feet of water in storage. Ground water is discharged from the area by movement to the south, by evaporation and transpiration in

Valley-chiral quantum Hall state in graphene superlattice structure

Science.gov (United States)

Tian, H. Y.; Tao, W. W.; Wang, J.; Cui, Y. H.; Xu, N.; Huang, B. B.; Luo, G. X.; Hao, Y. H.

2016-05-01

We theoretically investigate the quantum Hall effect in a graphene superlattice (GS) system, in which the two valleys of graphene are coupled together. In the presence of a perpendicular magnetic field, an ordinary quantum Hall effect is found with the sequence σxy=ν e^2/h(ν=0,+/-1,+/-2,\\cdots) . At the zeroth Hall platform, a valley-chiral Hall state stemming from the single K or K' valley is found and it is localized only on one sample boundary contributing to the longitudinal conductance but not to the Hall conductivity. Our findings may shed light on the graphene-based valleytronics applications.

Hierofonía and cosmology in indigenous art Sibundoy Valley

Directory of Open Access Journals (Sweden)

Óscar Fernando Sánchez Suárez

2013-01-01

Full Text Available An analysis of the large existing indigenous cultural diversity in South America as the initial part of the study and support of research is presented. It is also a reflection from the perspective of different authors on the thinking of man in relation to nature, archetypes, cosmogony and rituals. It is also woven with the history of the peoples or ethnic communities of Kamentzá and Inga. The inhabitants of Sibundoy Valley, Putumayo Colombia show a strong influence of Eastern and other Amerindian cultures that have had a great relevance and importance on other cultures of the continent. Similarly, it treats the nature of the Indian art and aesthetics as an important aspect in the development of cosmology and the spirituality embodied in the different objects and in the aesthetics in other elements of cultural elements proper to the Kamentzá and Inga cultures.

In Situ Densification Utilizing a Low-Viscosity Wetting Impregnant that Greating Reduces Processing Time to Produce Uniform Density Carbon-Carbon Composites

National Research Council Canada - National Science Library

Hoffman, Wesley

2002-01-01

High-performance carbon-carbon (C-C) composites possess a unique set of properties that make them desirable materials for high-temperature structural uses such as in rocket propulsion components, hypersonic vehicles, and aircraft brakes...

Observations of Air Quality at the Edge of Kathmandu, Nepal, and the Diurnal Cycle of Air Pollution In and Around the Kathmandu Valley

Science.gov (United States)

Panday, A. K.; Prinn, R. G.; Regmi, R. P.

2006-12-01

The Kathmandu Valley is a bowl-shaped basin in the Nepal Himalaya, with a rapidly growing city surrounded by rice fields and steep terraced and forested mountain slopes. The valley's air quality is influenced by urban and rural emissions, nocturnal pooling of cold air, slope winds, and a daily exchange of air through mountain passes. To understand these processes and to inform air pollution policy in Nepal, we have carried out the most comprehensive study of air pollution in Nepal to date. During the 9-month dry season of 2004-2005, we carried out continuous measurements every minute of carbon monoxide, ozone, PM10, wind speed, wind direction, solar radiation, temperature, and humidity on the eastern edge of Kathmandu city, at a site that daily received air from both the city and rural areas. We recorded the diurnal cycle of the vertical temperature structure and stability with temperature loggers on towers and mountains. A sodar measured the mixed layer height and upper-level winds. 24-hour simultaneous bag sampling campaigns on mountain peaks, passes, the rural valley, and within the city provided glimpses of the spatial patterns of the diurnal cycle of CO -- a useful tracer of anthropogenic emissions. We measured winds on mountain passes and ozone on mountain peaks. At our main measurement site we found a daily-recurring pattern of CO and PM10, with an afternoon low showing rural background levels, even though the arriving air had traversed the city. This was followed by an evening peak starting at sunset, a second low late at night, and a morning peak enhanced by re-circulation. Pollutants emitted in the valley only traveled out of the valley between the late morning and sunset. During winter months, rush hour was outside of this period, enhancing the morning and evening peaks. Within the city, ozone dropped to zero at night. At mid-day we observed an ozone peak enhanced by photochemical production when the air mass that had been stagnant over the city swept

Commercial production of ethanol in the San Luis Valley, Colorado. Final report

Energy Technology Data Exchange (ETDEWEB)

Hewlett, E.M.; Erickson, M.V.; Ferguson, C.D.; Boswell, B.S.; Walter, K.M.; Hart, M.L.; Sherwood, P.B.

1983-07-01

The commercial feasibility of producing between 76 and 189 million liters (20 to 50 million gallons) of ethanol annually in the San Luis Valley, Colorado using geothermal energy as the primary heat source was assessed. The San Luis Valley is located in south-central Colorado. The valley is a high basin situated approximately 2316 meters (7600 feet) above sea level which contains numerous warm water wells and springs. A known geothermal resource area (IGRA) is located in the east-central area of the valley. The main industry in the valley is agriculture, while the main industry in the surrounding mountains is lumber. Both of these industries can provide feedstocks for the production of ethanol.

A scheme for the uniform mapping and monitoring of earth resources and environmental complexes: An assessment of natural vegetation, environmental, and crop analogs. [Sierra-Lahontan and Colorado Plateaus, Northern Great Valley (CA), and Louisiana Coastal Plain

Science.gov (United States)

Poulton, C. E.; Welch, R. I. (Principal Investigator)

1975-01-01

The author has identified the following significant results. A study was performed to develop and test a procedure for the uniform mapping and monitoring of natural ecosystems in the semi-arid and wood regions of the Sierra-Lahontan and Colorado Plateau areas, and for the estimating of rice crop production in the Northern Great Valley (Ca.) and the Louisiana Coastal Plain. ERTS-1 and high flight and low flight aerial photos were used in a visual photointerpretation scheme to identify vegetation complexes, map acreages, and evaluate crop vigor and stress. Results indicated that the vegetation analog concept is valid; that depending on the kind of vegetation and its density, analogs are interpretable at different levels in the hierarchical classification from second to the fourth level. The second level uses physiognomic growth form-structural criteria, and the fourth level uses floristic or taxonomic criteria, usually at generic level. It is recommended that analog comparisons should be made in relatively small test areas where large homogeneous examples can be found of each analog.

Cryostratigraphy and sedimentology of high-Arctic fjord-valleys

OpenAIRE

Gilbert, Graham Lewis

2018-01-01

Fjord-valleys, as sediment-filled palaeofjords, are characteristic of formerly glaciated mountainous coastal areas. High-Arctic fjord-valleys commonly host permafrost, but are poorly accessible and hence have drawn relatively little research. The research presented in this thesis combines the methods of cryostratigraphy, clastic sedimentology, sequence stratigraphy, geomorphology and geochronology to investigate the sedimentary infilling, permafrost formation and late Quaternary landscape dev...

Carbon isotope ratios of great plains soils and in wheat-fallow systems

International Nuclear Information System (INIS)

Follett, R.F.; Paul, E.A.; Leavitt, S.W.; Halvorson, A.D.; Lyon, D.; Peterson, G.A.

1997-01-01

The purposes of this study were to improve knowledge of regional vegetation patterns of C3 and C4 plants in the North American Great Plains and to use delta 13C methodology and long-term research sites to determine contributions of small-grain crops to total soil organic carbon (SOC) now present. Archived and recent soil samples were used. Detailed soil sampling was in 1993 at long-term sites near Akron, CO, and Sidney, NE. After soil sieving, drying, and deliming, SOC and delta 13C were determined using an automated C/N analyzer interfaced to an isotope-ratio mass spectrometer. Yield records from long-term experimental sites were used to estimate the amount of C3 plant residue C returned to the soil. Results from delta 13C analyses of soils from near Waldheim, Saskatchewan, to Big Springs, TX, showed a strong north to south decrease in SOC derived from C3 plants and a corresponding increase from C4 plants. The delta 13C analyses gave evidence that C3 plant residue C (possibly from shrubs) is increasing at the Big Springs, TX, and Lawton, OK, sites. Also, delta 13C analyses of subsoil and topsoil layers shows evidence of a regional shift to more C3 species, possibly because of a cooler climate during the past few hundreds to thousands of years. Data from long-term research sites indicate that the efficiency of incorporation of small-grain crop residue C was about 5.4% during 84 yr at Akron, CO, and about 10.5% during 20 yr at Sidney, NE. The 14C age of the SOC at 0- to 10-cm depth was 193 yr and at 30 to 45 cm was 4000 yr; 14C age of nonhydrolyzable C was 2000 and 7000 yr for these same two respective depths. Natural partitioning of the 13C isotope by the photosynthetic pathways of C3 and C4 plants provides a potentially powerful tool to study SOC dynamics at both regional and local scales

Cosmic Reason of Great Glaciation

Science.gov (United States)

Bagrov, Alexander; Murtazov, Andrey

The origin of long-time and global glaciations in the past of our planet, which have been named «great», is still not clear. Both the advance of glaciers and their subsequent melting must be connected with some energy consuming processes. There is a powerful energy source permanently functioning throughout the Earth’s history - the solar radiation. The equality of the incoming shortwave solar energy and the transformed long-wave energy emitted by the Earth provides for the whole ecosphere’s sustainable evolution. Great glaciations might be caused by space body falls into the world oceans. If the body is large enough, it can stir waters down to the bottom. The world waters are part of the global heat transfer from the planet’s equator to its poles (nowadays, mostly to the North Pole). The mixing of the bottom and surface waters breaks the circulation of flows and they stop. The termination of heat transfer to the poles will result in an icecap at high latitudes which in its turn will decrease the total solar heat inflow to the planet and shift the pole ice boarder to the equator. This positive feedback may last long and result in long-time glaciations. The oceanic currents will remain only near the equator. The factor obstructing the global cooling is the greenhouse effect. Volcanic eruptions supply a lot of carbon dioxide into the atmosphere. When due to the increased albedo the planet receives less solar heat, plants bind less carbon oxide into biomass and more of it retains in the atmosphere. Therefore, the outflow of heat from the planet decreases and glaciations does not involve the whole planet. The balance established between the heat inflow and heat losses is unstable. Any imbalance acts as a positive feed-back factor. If the volcanic activity grows, the inflow of the carbon dioxide into the atmosphere will cause its heating-up (plants will fail to reproduce themselves quickly enough to utilize the carbonic acid). The temperature growth will lead to

Montana Valley and Foothill Prairies Ecoregion: Chapter 6 in Status and trends of land change in the Western United States--1973 to 2000

Science.gov (United States)

Taylor, Janis L.

2012-01-01

The Montana Valley and Foothill Prairies Ecoregion comprises numerous intermountain valleys and low-elevation foothill prairies spread across the western half of Montana, on both sides of the Continental Divide (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The ecoregion, which covers approximately 64,658 km2 (24,965 mi2), includes the Flathead Valley and the valleys surrounding Helena, Missoula, Bozeman, Billings, Anaconda, Dillon, and Lewistown (fig. 1). These valleys are generally characterized by shortgrass prairie vegetation and are flanked by forested mountains (Woods and others, 1999); thus, the valleys’ biotas with regards to fish and insects are comparable. In many cases, the valleys are conduits for some of the largest rivers in the state, including Clark Fork and the Missouri, Jefferson, Madison, Flathead, Yellowstone, Gallatin, Smith, Big Hole, Bitterroot, and Blackfoot Rivers (fig. 2). The Montana Valley and Foothill Prairies Ecoregion also includes the “Rocky Mountain front,” an area of prairies along the eastern slope of the northern Rocky Mountains. Principal land uses within the ecoregion include farming, grazing, and mining. The valleys serve as major transportation and utility corridors and also contain the majority of Montana’s human population. The Montana Valley and Foothill Prairies Ecoregion extends into 17 mostly rural counties throughout western Montana. Only three of the counties—Carbon, Yellowstone, and Missoula—are part of a metropolitan statistical area with contiguous built-up areas tied to an employment center. Nearly two-thirds of Montana residents live in nonmetropolitan counties (Albrecht, 2008). Ten of the counties within the ecoregion had population growth rates greater than national averages (9–13 percent) between 1970 and 2000 (table 1). Ravalli and Gallatin Counties had the highest growth rates. Population growth was largely due to amenity-related inmigration and an economy dependent on tourism

Large tunable valley splitting in edge-free graphene quantum dots on boron nitride

Science.gov (United States)

Freitag, Nils M.; Reisch, Tobias; Chizhova, Larisa A.; Nemes-Incze, Péter; Holl, Christian; Woods, Colin R.; Gorbachev, Roman V.; Cao, Yang; Geim, Andre K.; Novoselov, Kostya S.; Burgdörfer, Joachim; Libisch, Florian; Morgenstern, Markus

2018-05-01

Coherent manipulation of the binary degrees of freedom is at the heart of modern quantum technologies. Graphene offers two binary degrees: the electron spin and the valley. Efficient spin control has been demonstrated in many solid-state systems, whereas exploitation of the valley has only recently been started, albeit without control at the single-electron level. Here, we show that van der Waals stacking of graphene onto hexagonal boron nitride offers a natural platform for valley control. We use a graphene quantum dot induced by the tip of a scanning tunnelling microscope and demonstrate valley splitting that is tunable from -5 to +10 meV (including valley inversion) by sub-10-nm displacements of the quantum dot position. This boosts the range of controlled valley splitting by about one order of magnitude. The tunable inversion of spin and valley states should enable coherent superposition of these degrees of freedom as a first step towards graphene-based qubits.

A Transformative Undergraduate Field Trip to the Grand Canyon and Death Valley

Science.gov (United States)

Smith, J. A.

2014-12-01

Seeing the iconic Grand Canyon and Death Valley in person is a transformative experience for most geologists, including nine undergraduate geology students from upstate New York. The students were enrolled in a one-credit course designed around a nine-day spring-break field trip to Grand Canyon National Park (GCNP) and Death Valley National Park (DVNP). We met once a week before the trip to plan day-to-day activities and discuss background geologic information. Students selected a research topic related to our itinerary and wrote a guidebook entry for the topic. Students' entries were combined with papers, maps, and background material to make a guidebook. The printed guidebooks provided students with a "publication" of their work to show to others and refer to in the field. The nine-day field trip started with a flight into Las Vegas, NV, on 3/1/14. We spent three nights camping at the South Rim of the Grand Canyon, one night camping in Valley of Fire State Park (VOFSP, 55 mi N of Las Vegas), and three nights staying at the Shoshone Education and Research Center (SHEAR) east of Death Valley. Highlights of the trip included the hike along the Bright Angel Trail (and fault) to Plateau Point and recognition of the Great Unconformity at GCNP; the White Domes loop hike, camping at the Beehives, and observation of the Muddy Mountain Overthrust in VOFSP; and hikes at Ubehebe Crater, Badwater Salt Flat, and Natural Bridge Canyon in DVNP. Each student presented his/her research topic at a pertinent point in the field trip; students were impressively well-prepared. One requirement of the course was a poster presentation on each student's research topic at our Undergraduate Research Symposium in April. For most of the students, the poster session was the first experience preparing and presenting a poster. In addition, the class gave a joint colloquium presentation to several hundred science majors and a number of science faculty at Saint Rose. Each student spoke for five

Completely independent electrical control of spin and valley in a silicene field effect transistor

International Nuclear Information System (INIS)

Zhai, Xuechao; Jin, Guojun

2016-01-01

One-atom-thick silicene is a silicon-based hexagonal-lattice material with buckled structure, where an electron fuses multiple degrees of freedom including spin, sublattice pseudospin and valley. We here demonstrate that a valley-selective spin filter (VSSF) that supports single-valley and single-spin transport can be realized in a silicene field effect transistor constructed of an npn junction, where an antiferromagnetic exchange field and a perpendicular electric field are applied in the p -doped region. The nontrivial VSSF property benefits from an electrically controllable state of spin-polarized single-valley Dirac cone. By reversing the electric field direction, the device can operate as a spin-reversed but valley-unreversed filter due to the dependence of band gap on spin and valley. Further, we find that all the possible spin-valley configurations of VSSF can be achieved just by tuning the electric field. Our findings pave the way to the realization of completely independent electrical control of spin and valley in silicene circuits. (paper)

Commercial production of ethanol in the San Luis Valley, Colorado. Final Report

Energy Technology Data Exchange (ETDEWEB)

Hewlett, E.M.; Erickson, M.V.; Ferguson, C.D.; Sherwood, P.B.; Boswell, B.S.; Walter, K.M.; Hart, M.L.

1983-07-01

The purpose of this study is to assess the commercial feasibility of producing between 76 and 189 million liters (20 and 50 million gallons) of ethanol annually in the San Luis Valley, Colorado using geothermal energy as the primary heat source. The San Luis Valley is located in south-central Colorado. The valley is a high basin situated approximately 2316 meters (7600 feet) above sea level which contains numerous warm water wells and springs. A known geothermal resource area (KGRA) is located in the east-central area of the valley. The main industry in the valley is agriculture, while the main industry in the surrounding mountains is lumber. Both of these industries can provide feedstock for the production of ethanol.

An examination of the factors governing the development of karst topography in the Cumberland Valley of Pennsylvania

International Nuclear Information System (INIS)

Ackerman, R.V.

1993-01-01

The landscape of the Cumberland Valley of South Central Pennsylvania is dominated by karst topography. A study was initiated to determine if the development of karst was controlled primarily by geologic structure or by lithologic differences. Existing data concerning the geographic locations of karst features, the hydrogeologic characteristics of the Cumberland Valley, and the chemistry of the eleven carbonate formations within the 518 km 2 study area were compiled. Data concerning 366 mapped sinkholes and over 9,000 additional karst features and their relations to the structural, lithological and spatial characteristics of the study area were collected and compiled into the database. Other factors contributing to karst development such as groundwater flow, soil and colluvium characteristics, and geographic distribution were considered. The data suggest that structure dominates lithology in the development of karst features within the study area. Structural features such as fractures, joints and folds, which create secondary porosity, are prerequisite for solution of the carbonate bedrock. Joint systems, fold axes, igneous intrusions, caves, springs and groundwater flow have a significant impact on the development of karst features. The presence of faults proved inconclusive. There are a greater number of karst features per unit area in areas of purer limestones (units with a lower percentage of acid insoluble residue). Lithological variations impact karst development only when structural features are present to provide secondary porosity that enhances chemical weathering. The distribution of karst features and the geologic factors governing their development and distribution should be taken into account when land-use decisions in karst terrains are made

Ultrafast generation of pseudo-magnetic field for valley excitons in WSe2 monolayers

KAUST Repository

Kim, J.

2014-12-04

The valley pseudospin is a degree of freedom that emerges in atomically thin two-dimensional transition metal dichalcogenides (MX2). The capability to manipulate it, in analogy to the control of spin in spintronics, can open up exciting opportunities. Here, we demonstrate that an ultrafast and ultrahigh valley pseudo-magnetic field can be generated by using circularly polarized femtosecond pulses to selectively control the valley degree of freedom in monolayer MX2. Using ultrafast pump-probe spectroscopy, we observed a pure and valley-selective optical Stark effect in WSe2 monolayers from the nonresonant pump, resulting in an energy splitting of more than 10 milli-electron volts between the K and K′ valley exciton transitions. Our study opens up the possibility to coherently manipulate the valley polarization for quantum information applications.

Ultrafast generation of pseudo-magnetic field for valley excitons in WSe2 monolayers

KAUST Repository

Kim, J.; Hong, X.; Jin, C.; Shi, S.-F.; Chang, C.-Y. S.; Chiu, Ming-Hui; Li, Lain-Jong; Wang, F.

2014-01-01

The valley pseudospin is a degree of freedom that emerges in atomically thin two-dimensional transition metal dichalcogenides (MX2). The capability to manipulate it, in analogy to the control of spin in spintronics, can open up exciting opportunities. Here, we demonstrate that an ultrafast and ultrahigh valley pseudo-magnetic field can be generated by using circularly polarized femtosecond pulses to selectively control the valley degree of freedom in monolayer MX2. Using ultrafast pump-probe spectroscopy, we observed a pure and valley-selective optical Stark effect in WSe2 monolayers from the nonresonant pump, resulting in an energy splitting of more than 10 milli-electron volts between the K and K′ valley exciton transitions. Our study opens up the possibility to coherently manipulate the valley polarization for quantum information applications.

Measurements of Carbon Dioxide, Methane, and Other Related Tracers at High Spatial and Temporal Resolution in an Urban Environment

Science.gov (United States)

Yasuhara, Scott; Forgeron, Jeff; Rella, Chris; Franz, Patrick; Jacobson, Gloria; Chiao, Sen; Saad, Nabil

2013-04-01

The ability to quantify sources and sinks of carbon dioxide and methane on the urban scale is essential for understanding the atmospheric drivers to global climate change. In the 'top-down' approach, overall carbon fluxes are determined by combining remote measurements of carbon dioxide concentrations with complex atmospheric transport models, and these emissions measurements are compared to 'bottom-up' predictions based on detailed inventories of the sources and sinks of carbon, both anthropogenic and biogenic in nature. This approach, which has proven to be effective at continental scales, becomes challenging to implement at urban scales, due to poorly understood atmospheric transport models and high variability of the emissions sources in space (e.g., factories, highways, green spaces) and time (rush hours, factory shifts and shutdowns, and diurnal and seasonal variation in residential energy use). New measurement and analysis techniques are required to make sense of the carbon dioxide signal in cities. Here we present detailed, high spatial- and temporal- resolution greenhouse gas measurements made by multiple Picarro-CRDS analyzers in Silicon Valley in California. Real-time carbon dioxide data from a 20-month period are combined with real-time carbon monoxide, methane, and acetylene to partition the observed carbon dioxide concentrations between different anthropogenic sectors (e.g., transport, residential) and biogenic sources. Real-time wind rose data are also combined with real-time methane data to help identify the direction of local emissions of methane. High resolution WRF models are also included to better understand the dynamics of the boundary layer. The ratio between carbon dioxide and carbon monoxide is shown to vary over more than a factor of two from season to season or even from day to night, indicating rapid but frequent shifts in the balance between different carbon dioxide sources. Additional information is given by acetylene, a fossil fuel

Highly stretchable carbon aerogels.

Science.gov (United States)

Guo, Fan; Jiang, Yanqiu; Xu, Zhen; Xiao, Youhua; Fang, Bo; Liu, Yingjun; Gao, Weiwei; Zhao, Pei; Wang, Hongtao; Gao, Chao

2018-02-28

Carbon aerogels demonstrate wide applications for their ultralow density, rich porosity, and multifunctionalities. Their compressive elasticity has been achieved by different carbons. However, reversibly high stretchability of neat carbon aerogels is still a great challenge owing to their extremely dilute brittle interconnections and poorly ductile cells. Here we report highly stretchable neat carbon aerogels with a retractable 200% elongation through hierarchical synergistic assembly. The hierarchical buckled structures and synergistic reinforcement between graphene and carbon nanotubes enable a temperature-invariable, recoverable stretching elasticity with small energy dissipation (~0.1, 100% strain) and high fatigue resistance more than 10 6 cycles. The ultralight carbon aerogels with both stretchability and compressibility were designed as strain sensors for logic identification of sophisticated shape conversions. Our methodology paves the way to highly stretchable carbon and neat inorganic materials with extensive applications in aerospace, smart robots, and wearable devices.

Source characterization of major emission sources in the Imperial and Mexicali Valleys along the US/Mexico border

Energy Technology Data Exchange (ETDEWEB)

Watson, J.G.; Chow, J.C. [Desert Research Institute, 2215 Raggio Pkwy., 89512 Reno, NV (United States)

2001-08-10

Chemical profiles for particle emissions are needed for source apportionment studies using the chemical mass balance (CMB) receptor model. Source measurements of geological sources, motor vehicle exhaust, vegetative burning (e.g. asparagus, field burning, charbroil cooking), and industrial sources (e.g. oil-fueled glass plant, manure-fueled power plants) were acquired as part of the Imperial/Mexicali Valley Cross Border PM{sub 10} Transport Study in 1992. Six different source sampling techniques (i.e. hot- and diluted-exhaust sampling, ground-based source sampling, particle sweeping/grab sampling, vacuum sampling, and laboratory resuspension sampling) were applied to acquire filter samples of PM{sub 2.5} and PM{sub 10} (particulate matter with aerodynamic diameters <2.5 and 10 {mu}m, respectively). Filter samples were analyzed for mass by gravimetry, elements (Na to U) by X-ray fluorescence, anions (Cl{sup -}, NO{sub 3}{sup -}, SO{sub 4}{sup =}) by ion chromatography, ammonium (NH{sub 4}{sup +}) by automated colorimetry, soluble sodium (Na{sup +}) and potassium (K{sup +}) by atomic absorption spectrophotometry, and organic and elemental carbon (OC, EC) by thermal/optical reflectance. Concentration data were acquired for a total of 50 chemical species. Elevated abundances of crustal components (Al, Si, K, Ca, Fe) from geological material, carbon (OC, EC) and trace elements (Br, Pb) from vehicle exhausts, carbon (OC, EC) and ions (K{sup +}, Cl{sup -}) from vegetative burning, ions (SO{sub 4}{sup =}, NH{sub 4}{sup +}, Na{sup +}, K{sup +}, Cl{sup -}) and elements (Cl, Se) from a manure-fueled power plants, and sulfur and trace elements (Na{sup +}, Pb, Se, Ni, V) from an oil-fueled glass plant were found in the resulting source profiles. Abundances of crustal species (e.g. Al, Si, Ca) in the Imperial/Mexicali Valley geological profiles are more than twice those found in central and southern California. Abundances of lead in motor vehicle exhausts indicate different

West Valley Reprocessing Plant. Safety analysis plant, supplement 18

International Nuclear Information System (INIS)

1975-01-01

Supplement 18 contains the following additions to Appendix II--5.0 Geology and Seismology: Section 12 ''Seismic Investigations for Spent Fuel Reprocessing Facility at West Valley, New York,'' October 20, 1975, and Section 13 ''Earthquake Return Period Analysis at West Valley, New York, for Nuclear Fuel Services, Inc.'' November 5, 1975

Source contributions to atmospheric fine carbon particle concentrations

Science.gov (United States)

Andrew Gray, H.; Cass, Glen R.

A Lagrangian particle-in-cell air quality model has been developed that facilitates the study of source contributions to atmospheric fine elemental carbon and fine primary total carbon particle concentrations. Model performance was tested using spatially and temporally resolved emissions and air quality data gathered for this purpose in the Los Angeles area for the year 1982. It was shown that black elemental carbon (EC) particle concentrations in that city were dominated by emissions from diesel engines including both on-highway and off-highway applications. Fine primary total carbon particle concentrations (TC=EC+organic carbon) resulted from the accumulation of small increments from a great variety of emission source types including both gasoline and diesel powered highway vehicles, stationary source fuel oil and gas combustion, industrial processes, paved road dust, fireplaces, cigarettes and food cooking (e.g. charbroilers). Strategies for black elemental carbon particle concentration control will of necessity need to focus on diesel engines, while controls directed at total carbon particle concentrations will have to be diversified over a great many source types.

Size effects in many-valley fluctuations in semiconductors

International Nuclear Information System (INIS)

Sokolov, V.N.; Kochelap, V.A.

1995-08-01

We present the results of theoretical investigations of nonhomogeneous fluctuations in submicron active regions of many-valley semiconductors with equivalent valleys(Ge, Si-type), where the dimension 2d of the region is comparable to or less than the intervalley diffusion relaxation length L iv . It is shown that for arbitrary orientations of the valley axes (the crystal axes) with respect to lateral sample surfaces, the fluctuation spectra depend on the bias voltage applied to the layer in the region of weak nonheating electric fields. The new physical phenomenon is reported: the fluctuation spectra depend on the sample thickness, with 2d iv the suppression of fluctuations arises for fluctuation frequencies ω -1 iv , τ -1 iv is the characteristic intervalley relaxation time. (author). 43 refs, 5 figs

Energy Band Gap Dependence of Valley Polarization of the Hexagonal Lattice

Science.gov (United States)

Ghalamkari, Kazu; Tatsumi, Yuki; Saito, Riichiro

2018-02-01

The origin of valley polarization of the hexagonal lattice is analytically discussed by tight binding method as a function of energy band gap. When the energy gap decreases to zero, the intensity of optical absorption becomes sharp as a function of k near the K (or K') point in the hexagonal Brillouin zone, while the peak intensity at the K (or K') point keeps constant with decreasing the energy gap. When the dipole vector as a function of k can have both real and imaginary parts that are perpendicular to each other in the k space, the valley polarization occurs. When the dipole vector has only real values by selecting a proper phase of wave functions, the valley polarization does not occur. The degree of the valley polarization may show a discrete change that can be relaxed to a continuous change of the degree of valley polarization when we consider the life time of photo-excited carrier.

Asymmetric valley-resolved beam splitting and incident modes in slanted graphene junctions

International Nuclear Information System (INIS)

Hsieh, S. H.; Chu, C. S.

2016-01-01

Electron injection into a graphene sheet through a slanted armchair graphene nanoribbon (AGNR) is investigated. An incident mode, or subband, in the AGNR is valley-unpolarized. Our attention is on the valley-resolved nature of the injected electron beams and its connection to the incident mode. It is known for a normal injection that an incident mode will split symmetrically into two valley-resolved beams of equal intensity. We show, in contrast, that slanted injections result in asymmetric valley-resolved beam splitting. The most asymmetric beam splitting cases, when one of the valley-resolved beams has basically disappeared, are found and the condition derived. This is shown not due to trigonal warping because it holds even in the low incident energy regime, as long as collimation allows. These most asymmetric beam splitting cases occur at energies within an energy interval near and include the subband edge of an incident mode. The physical picture is best illustrated by a projection of the slanted AGNR subband states onto that of the 2D graphene sheet. It follows that the disappearing of a valley-resolved beam coincides with the situation that the group velocities of the projected states in the corresponding valley are in backward directions

The Drentsche Aa valley system

International Nuclear Information System (INIS)

Gans, W. de.

1981-01-01

This thesis is composed of five papers concerned with Late Quaternary geology and geomorphology of the Aa valley system. The correlation and chronostratigraphic position of the layers have been established by radiocarbon dating. (Auth.)

Land Subsidence Caused by Groundwater Exploitation in Quetta Valley, Pakistan

Directory of Open Access Journals (Sweden)

Najeebullah Kakar

2016-12-01

Full Text Available Land subsidence is affecting several metropolitan cities in developing as well as developed countries around the world such as Nagoya (Japan, Shanghai (China, Venice (Italy and San Joaquin valley (United States. This phenomenon is attributed to natural as well as anthropogenic activities that include extensive groundwater withdrawals. Quetta is the largest city of Balochistan province in Pakistan. This valley is mostly dry and ground water is the major source for domestic and agricultural consumption. The unplanned use of ground water resources has led to the deterioration of water quality and quantity in the Quetta valley. Water shortage in the region was further aggravated by the drought during (1998-2004 that hit the area forcing people to migrate from rural to urban areas. Refugees from the war torn neighboring Afghanistan also contributed to rapid increase in population of Quetta valley that has increased from 0.26 million in 1975 to 3.0 million in 2016. The objective of this study was to measure the land subsidence in Quetta valley and identify the effects of groundwater withdrawals on land subsidence. To achieve this goal, data from five Global Positioning System (GPS stations were acquired and processed. Furthermore the groundwater decline data from 41 observation wells during 2010 to 2015 were calculated and compared with the land deformation. The results of this study revealed that the land of Quetta valley is subsiding from 30mm/y on the flanks to 120 mm/y in the central part. 1.5-5.0 m/y of groundwater level drop was recorded in the area where the rate of subsidence is highest. So the extensive groundwater withdrawals in Quetta valley is considered to be the driving force behind land subsidence.

Direct measurement of exciton valley coherence in monolayer WSe2

KAUST Repository

Hao, Kai; Moody, Galan; Wu, Fengcheng; Dass, Chandriker Kavir; Xu, Lixiang; Chen, Chang Hsiao; Sun, Liuyang; Li, Ming-yang; Li, Lain-Jong; MacDonald, Allan H.; Li, Xiaoqin

2016-01-01

In crystals, energy band extrema in momentum space can be identified by a valley index. The internal quantum degree of freedom associated with valley pseudospin indices can act as a useful information carrier, analogous to electronic charge

Hydrothermal zebra dolomite in the Great Basin, Nevada--attributes and relation to Paleozoic stratigraphy, tectonics, and ore deposits

Science.gov (United States)

Diehl, S.F.; Hofstra, A.H.; Koenig, A.E.; Emsbo, P.; Christiansen, W.; Johnson, Chad

2010-01-01

In other parts of the world, previous workers have shown that sparry dolomite in carbonate rocks may be produced by the generation and movement of hot basinal brines in response to arid paleoclimates and tectonism, and that some of these brines served as the transport medium for metals fixed in Mississippi Valley-type (MVT) and sedimentary exhalative (Sedex) deposits of Zn, Pb, Ag, Au, or barite. Numerous occurrences of hydrothermal zebra dolomite (HZD), comprised of alternating layers of dark replacement and light void-filling sparry or saddle dolomite, are present in Paleozoic platform and slope carbonate rocks on the eastern side of the Great Basin physiographic province. Locally, it is associated with mineral deposits of barite, Ag-Pb-Zn, and Au. In this paper the spatial distribution of HZD occurrences, their stratigraphic position, morphological characteristics, textures and zoning, and chemical and stable isotopic compositions were determined to improve understanding of their age, origin, and relation to dolostone, ore deposits, and the tectonic evolution of the Great Basin. In northern and central Nevada, HZD is coeval and cogenetic with Late Devonian and Early Mississippian Sedex Au, Zn, and barite deposits and may be related to Late Ordovician Sedex barite deposits. In southern Nevada and southwest California, it is cogenetic with small MVT Ag-Pb-Zn deposits in rocks as young as Early Mississippian. Over Paleozoic time, the Great Basin was at equatorial paleolatitudes with episodes of arid paleoclimates. Several occurrences of HZD are crosscut by Mesozoic or Cenozoic intrusions, and some host younger pluton-related polymetallic replacement and Carlin-type gold deposits. The distribution of HZD in space (carbonate platform, margin, and slope) and stratigraphy (Late Neoproterozoic Ediacaran-Mississippian) roughly parallels that of dolostone and both are prevalent in Devonian strata. Stratabound HZD is best developed in Ediacaran and Cambrian units, whereas

Valley polarization in magnetically doped single-layer transition-metal dichalcogenides

KAUST Repository

Cheng, Yingchun

2014-04-28

We demonstrate that valley polarization can be induced and controlled in semiconducting single-layer transition-metal dichalcogenides by magnetic doping, which is important for spintronics, valleytronics, and photonics devices. As an example, we investigate Mn-doped MoS2 by first-principles calculations. We study how the valley polarization depends on the strength of the spin orbit coupling and the exchange interaction and discuss how it can be controlled by magnetic doping. Valley polarization by magnetic doping is also expected for other honeycomb materials with strong spin orbit coupling and the absence of inversion symmetry.

Optically initialized robust valley-polarized holes in monolayer WSe2

KAUST Repository

Hsu, Wei-Ting; Chen, Yen-Lun; Chen, Chiang-Hsiao; Liu, Pang-Shiuan; Hou, Tuo-Hung; Li, Lain-Jong; Chang, Wen-Hao

2015-01-01

a unique platform to develop such valleytronic devices, the anticipated long-lived valley pseudospin has not been observed yet. Here we demonstrate that robust valley-polarized holes in monolayer WSe2 can be initialized by optical pumping. Using time

Changing Land Use from Cotton to Bioenergy Crops in the Southern Great Plains: Implications on Carbon and Water Vapor Fluxes

Science.gov (United States)

Rajan, N.; Sharma, S.

2016-12-01

We are facing an unprecedented challenge in securing America's energy future. To address this challenge, increased biofuel crop production is needed. Although first-generation biofuels like corn ethanol are available, second-generation biofuels are gaining importance because they don't directly compete with food production. Second-generation biofuels are made from the by-products of intensive agriculture or from less-intensive agriculture on more marginal lands. The Southwestern U.S. Cotton Belt can play a significant role in this effort through a change from more conventional crops (like continuous cotton) to second-generation biofuel feedstocks (biomass sorghum and perennial grasses). While we believe there would be environmental benefits associated with this change in land use, their exact nature and magnitude have not been investigated for this region. The overall goal of the proposed study was to investigate the water and carbon (C) fluxes associated with the change in agricultural land use to biofuels-dominated cropping systems in the semi-arid Southwestern U.S. Cotton Belt region. Eddy covariance flux towers were established at selected producer fields (cotton, perennial grasses and biomass sorghum) in the Southern Great Plains region. The fluxes of carbon dioxide, water vapor and sensible heat between the surface and the atmosphere will be measured throughout the year. The results have demonstrated that the dynamics of C and water vapor fluxes for these agroecosystems were strongly affected by environmental variables, management factors, and crop phenology. Detailed results will be presented at the meeting.

Carbon nanotubes from synthesis to in vivo biomedical applications.

Science.gov (United States)

Sajid, Muhammad Imran; Jamshaid, Usama; Jamshaid, Talha; Zafar, Nadiah; Fessi, H; Elaissari, Abdelhamid

2016-03-30

Owing to their unique and interesting properties, extensive research round the globe has been carried out on carbon nanotubes and carbon nanotubes based systems to investigate their practical usefulness in biomedical applications. The results from these studies demonstrate a great promise in their use in targeted drug delivery systems, diagnostic techniques and in bio-analytical applications. Although, carbon nanotubes possess quite interesting properties, which make them potential candidates in the biomedical science, but they also have some inherent properties which arise great concern regarding their biosafety. In this comprehensive review, we have discussed different aspects of carbon nanotubes and carbon nanotube based systems related to biomedical applications. In the beginning, a short historical account of these tiny yet powerful particles is given followed by discussion regarding their types, properties, methods of synthesis, large scale production method, purification techniques and characterization aspects of carbon nanotubes. In the second part of the review, the functionalization of carbon nanotubes is reviewed in detail, which is not only important to make them biocompatible and stable in biological systems but also render them a great property of loading various biomolecules, diagnostic and therapeutic moieties resulting in diversified applications. In the final part of the review, emphasis is given on the pharmacokinetic aspects of carbon nanotubes including administration routes, absorption mechanisms, distribution and elimination of carbon nanotubes based systems. Lastly, a comprehensive account about the potential biomedical applications has been given followed by insights into the future. Copyright © 2016 Elsevier B.V. All rights reserved.

Life cycle assessment of the transmission network in Great Britain

International Nuclear Information System (INIS)

Harrison, Gareth P.; Maclean, Edward J.; Karamanlis, Serafeim; Ochoa, Luis F.

2010-01-01

Analysis of lower carbon power systems has tended to focus on the operational carbon dioxide (CO 2 ) emissions from power stations. However, to achieve the large cuts required it is necessary to understand the whole-life contribution of all sectors of the electricity industry. Here, a preliminary assessment of the life cycle carbon emissions of the transmission network in Great Britain is presented. Using a 40-year period and assuming a static generation mix it shows that the carbon equivalent emissions (or global warming potential) of the transmission network are around 11 gCO 2-eq /kWh of electricity transmitted and that almost 19 times more energy is transmitted by the network than is used in its construction and operation. Operational emissions account for 96% of this with transmission losses alone totalling 85% and sulphur hexafluoride (SF 6 ) emissions featuring significantly. However, the CO 2 embodied within the raw materials of the network infrastructure itself represents a modest 3%. Transmission investment decisions informed by whole-life cycle carbon assessments of network design could balance higher financial and carbon 'capital' costs of larger conductors with lower transmission losses and CO 2 emissions over the network lifetime. This will, however, necessitate new regulatory approaches to properly incentivise transmission companies.

Interaction of valleys and circulation patterns (CPs on spatial precipitation patterns in southern Germany

Directory of Open Access Journals (Sweden)

M. Liu

2013-11-01

Full Text Available Topography exerts influence on the spatial precipitation distribution over different scales, known typically at the large scale as the orographic effect, and at the small scale as the wind-drift rainfall (WDR effect. At the intermediate scale (1~10 km, which is characterized by secondary mountain valleys, topography also demonstrates some effect on the precipitation pattern. This paper investigates such intermediate-scale topographic effects on precipitation patterns, focusing on narrow-steep valleys in the complex terrain of southern Germany, based on the daily observations over a 48 yr period (1960~2007 from a high-density rain-gauge network covering two sub-areas, Baden-Wuerttemberg (BW and Bavaria (BY. Precipitation data at the valley and non-valley stations are compared under consideration of the daily general circulation patterns (CPs classified by a fuzzy rule-based algorithm. Scatter plots of precipitation against elevation demonstrate a different behavior of valley stations comparing to non-valley stations. A detailed study of the precipitation time series for selected station triplets, each consisting of a valley station, a mountain station and an open station have been investigated by statistical analysis with the Kolmogorov–Smirnov (KS test supplemented by the One-way analysis of variance (One-way ANOVA and a graphical comparison of the mean precipitation amounts. The results show an interaction of valley orientation and the direction of the CPs at the intermediate scale, i.e. when the valley is shielded from the CP which carries the precipitation, the precipitation amount within the valley is comparable to that on the mountain crest, and both larger than the precipitation at the open station. When the valley is open to the CP, the precipitation within the valley is similar to the open station but much less than that on the mountain. Such phenomenon where the precipitation is "blind" to the valleys at the intermediate scale

Martian Cryogenic Carbonate Formation: Stable Isotope Variations Observed in Laboratory Studies

Science.gov (United States)

Socki, Richard A.; Niles, Paul B.; Sun, Tao; Fu, Qi; Romanek, Christopher S.; Gibson, Everett K. Jr.

2014-01-01

The history of water on Mars is tied to the formation of carbonates through atmospheric CO2 and its control of the climate history of the planet. Carbonate mineral formation under modern martian atmospheric conditions could be a critical factor in controlling the martian climate in a means similar to the rock weathering cycle on Earth. The combination of evidence for liquid water on the martian surface and cold surface conditions suggest fluid freezing could be very common on the surface of Mars. Cryogenic calcite forms easily from freezing solutions when carbon dioxide degasses quickly from Ca-bicarbonate-rich water, a process that has been observed in some terrestrial settings such as arctic permafrost cave deposits, lake beds of the Dry Valleys of Antarctica, and in aufeis (river icings) from rivers of N.E. Alaska. A series of laboratory experiments were conducted that simulated cryogenic carbonate formation on Mars in order to understand their isotopic systematics. The results indicate that carbonates grown under martian conditions show variable enrichments from starting bicarbonate fluids in both carbon and oxygen isotopes beyond equilibrium values.

Valley plugs, land use, and phytogeomorphic response: Chapter 14

Science.gov (United States)

Pierce, Aaron R.; King, Sammy L.; Shroder, John F.

2013-01-01

Anthropogenic alteration of fluvial systems can disrupt functional processes that provide valuable ecosystem services. Channelization alters fluvial parameters and the connectivity of river channels to their floodplains which is critical for productivity, nutrient cycling, flood control, and biodiversity. The effects of channelization can be exacerbated by local geology and land-use activities, resulting in dramatic geomorphic readjustments including the formation of valley plugs. Considerable variation in the response of abiotic processes, including surface hydrology, subsurface hydrology, and sedimentation dynamics, to channelization and the formation of valley plugs. Altered abiotic processes associated with these geomorphic features and readjustments influence biotic processes including species composition, abundance, and successional processes. Considerable interest exists for restoring altered fluvial systems and their floodplains because of their social and ecological importance. Understanding abiotic and biotic responses of channelization and valley-plug formation within the context of the watershed is essential to successful restoration. This chapter focuses on the primary causes of valley-plug formation, resulting fluvial-geomorphic responses, vegetation responses, and restoration and research needs for these systems.

Magnetoelectric control of valley and spin in a silicene nanoribbon modulated by the magnetic superlattices

Energy Technology Data Exchange (ETDEWEB)

An, Xing-Tao, E-mail: anxt@hku.hk

2015-03-20

The control of valley and spin degrees of freedom and the transport properties of electrons in a zigzag silicene nanoribbon modulated by the magnetic superlattices are investigated theoretically. Due to the valley–spin locking effect in silicene, the valley degree of freedom can be controlled by magnetic means. The valley or/and spin selection induced by the exchange field result in the perfect spin–valley filter and tunneling magnetoresistance effect in the double ferromagnetic barriers on the surface of the silicene nanoribbon. It is more interesting that there are valley-resolved minigaps and minibands in the zigzag silicene nanoribbon modulated by the magnetic superlattices which give rise to the periodically modulated spin (or/and valley) polarization and tunneling magnetoresistance. The results obtained may have certain practical significance in applications for future valleytronic and spintronic devices. - Highlights: • The valley can be controlled by a magnetic field in silicene. • The valley-resolved miniband transport is studied in the silicene superlattices. • There are the perfect spin–valley filter and tunneling magnetoresistance effect.

75 FR 48359 - Blackstone River Valley National Heritage Corridor Commission: Notice of Meeting

Science.gov (United States)

2010-08-10

... DEPARTMENT OF THE INTERIOR Office of the Secretary Blackstone River Valley National Heritage..., United States Code, that a meeting of the John H. Chafee Blackstone River Valley National Heritage..., Blackstone River Valley National Heritage Corridor Commission, One Depot Square, Woonsocket, RI 02895, Tel...

Atmospheric aerosol brown carbon in the high Himalayas

Science.gov (United States)

Kirillova, Elena; Decesari, Stefano; Marinoni, Angela; Bonasoni, Paolo; Vuillermoz, Elisa; Facchini, M. Cristina; Fuzzi, Sandro

2016-04-01

Anthropogenic light-absorbing atmospheric aerosol can reach very high concentrations in the planetary boundary layer in South-East Asia ("brown clouds"), affecting atmospheric transparency and generating spatial gradients of temperature over land with a possible impact on atmospheric dynamics and monsoon circulation. Besides black carbon (BC), an important light-absorbing component of anthropogenic aerosols is the organic carbon component known as 'brown carbon' (BrC). In this research, we provided first measurements of atmospheric aerosol BrC in the high Himalayas during different seasons. Aerosol sampling was conducted at the GAW-WMO Global station "Nepal Climate Observatory-Pyramid" (NCO-P) located in the high Khumbu valley at 5079 m a.s.l. in the foothills of Mt. Everest. PM10 aerosol samples were collected from July 2013 to November 2014. The sampling strategy was set up in order to discriminate the daytime valley breeze bringing polluted air masses up to the observatory and free tropospheric air during nighttime. Water-soluble BrC (WS-BrC) and methanol-soluble BrC (MeS-BrC) were extracted and analyzed using a UV/VIS spectrophotometer equipped with a 50 cm liquid waveguide capillary cell. In the polluted air masses, the highest levels of the BrC light absorption coefficient at 365 nm (babs365) were observed during the pre-monsoon season (1.83±1.46 Mm-1 for WS-BrC and 2.86±2.49 Mm-1 for MeS-BrC) and the lowest during the monsoon season (0.21±0.22 Mm-1 for WS-BrC and 0.32±0.29 Mm-1 for MeS-BrC). The pre-monsoon season is the most frequently influenced by a strong atmospheric brown cloud (ABC) transport to NCO-P due to increased convection and mixing layer height over South Asia combined with the highest up-valley wind speed and the increase of the emissions from open fires due to the agricultural practice along the Himalayas foothills and the Indo-Gangetic Plain. In contrast, the monsoon season is characterized by a weakened valley wind regime and an

Rock-fall potential in the Yosemite Valley, California

Science.gov (United States)

Wieczorek, G.F.; Morrissey, M.M.; Iovine, Giulio; Godt, Jonathan

1999-01-01

We used two methods of estimating rock-fall potential in the Yosemite Valley, California based on (1) physical evidence of previous rock-fall travel, in which the potential extends to the base of the talus, and (2) theoretical potential energy considerations, in which the potential can extend beyond the base of the talus, herein referred to as the rock-fall shadow. Rock falls in the valley commonly range in size from individual boulders of less than 1 m3 to moderate-sized falls with volumes of about 100,000 m3. Larger rock falls exceeding 100,000 m3, referred to as rock avalanches, are considered to be much less likely to occur based on the relatively few prehistoric rock-fall avalanche deposits in the Yosemite Valley. Because the valley has steep walls and is relatively narrow, there are no areas that are absolutely safe from large rock avalanches. The map shows areas of rock-fall potential, but does not predict when or how frequently a rock fall will occur. Consequently, neither the hazard in terms of probability of a rock fall at any specific location, nor the risk to people or facilities to such events can be assessed from this map.

Carbon dioxide exchange in the High Arctic - examples from terrestrial ecosystems

DEFF Research Database (Denmark)

Grøndahl, L.

of the growing season, which in combination with high temperatures increased uptake rates. The dry heath ecosystem in general gained carbon during the summer season in the order of magnitude -1.4 gCm-2 up to 32 gCm-2. This result is filling out a gap of knowledge on the response of high Arctic ecosystems...... the measurements conducted in the valley to a regional level. Including information on temporal and spatial variability in air temperature and radiation, together with NDVI and a vegetation map a regional estimate of the CO2 exchange during the summer was provided, elaborating the NDVI based estimate on net carbon...

Diversity and ecological ranges of plant species from dry inter-Andean valleys

DEFF Research Database (Denmark)

Quintana, Catalina

found on steep slopes and in ravines. These areas of original dry valley vegetation preserve many wild relatives of cultivated plants on the one hand and old lineages of other wild plant groups. Dry inter-Andean valleys (DIAVs) in Ecuador therefore makeup a biodiversity hot spot for both plants......Dry valleys in the American Andes and other mountains have provided excellent agricultural lands since millennia. Besides agriculture, wood extraction and the establishment of urban areas have diminished the native vegetation of these valleys. Consequently the original vegetation is now mostly...... and animals, but unfortunately only very few botanical studies have been carried out in these areas. This thesis intends to shed light on the vegetation of the Dry Ecuadorean Inter-Andean Valleys in four chapters, each with a different focus. 1) A review paper that summarizes all scientific knowledge...

GPS Imaging suggests links between climate, magmatism, seismicity, and tectonics in the Sierra Nevada-Long Valley Caldera-Walker Lane system, western United States

Science.gov (United States)

Hammond, W. C.; Blewitt, G.; Kreemer, C.; Smith, K.

2017-12-01

The Walker Lane is a region of complex active crustal transtension in the western Great Basin of the western United States, accommodating about 20% of the 50 mm/yr relative motion between the Pacific and North American plates. The Long Valley caldera lies in the central Walker Lane in eastern California, adjacent to the eastern boundary of the Sierra Nevada/Great Valley microplate, and experiences intermittent inflation, uplift, and volcanic unrest from the magma chamber that resides at middle crustal depths. Normal and transform faults accommodating regional tectonic transtension pass by and through the caldera, complicating the interpretation of the GPS-measured strain rate field, estimates of fault slip rates, and seismic hazard. Several dozen continuously recording GPS stations measure strain and uplift in the area with mm precision. They observe that the most recent episode of uplift at Long Valley began in mid-2011, continuing until late 2016, raising the surface by 100 mm in 6 years. The timing of the initiation of uplift coincides with the beginning of severe drought in California. Furthermore, the timing of a recent pause in uplift coincides with the very wet 2016-2017 winter, which saw approximately double normal snow pack. In prior studies, we showed that the timing of changes in geodetically measured uplift rate of the Sierra Nevada coincides with the timing of drought conditions in California, suggesting a link between hydrological loading and Sierra Nevada elevation. Here we take the analysis three steps further to show that changes in Sierra Nevada uplift rate coincide in time with 1) enhanced inflation at the Long Valley caldera, 2) shifts in the patterns and rates of horizontal tensor strain rate, and 3) seismicity patterns in the central Walker Lane. We use GPS solutions from the Nevada Geodetic Laboratory and the new GPS Imaging technique to produce robust animations of the time variable strain and uplift fields. The goals of this work are to

Preparation and characterization of carbon/SiC nanowire/Na-doped carbonated hydroxyapatite multilayer coating for carbon/carbon composites

International Nuclear Information System (INIS)

Leilei, Zhang; Hejun, Li; Kezhi, Li; Shouyang, Zhang; Qiangang, Fu; Yulei, Zhang; Jinhua, Lu; Wei, Li

2014-01-01

Highlights: • CSH coatings were prepared by combination of magnetron sputter ion plating, CVD and UECD. • Na + and CO 3 2− were developed to co-substitute hydroxyapatite. • SiC nanowires were introduced into Na-doped carbonated hydroxyapatite. • CSH coatings showed excellent cell activity and cell proliferation behavior. - Abstract: A carbon/SiC nanowire/Na-doped carbonated hydroxyapatite multilayer coating (CSH coating) was prepared on carbon/carbon composites using a combination method of magnetron sputter ion plating, chemical vapor deposition and ultrasound-assisted electrochemical deposition procedure. The morphology, microstructure and chemical composition of the coating were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The results showed that the CSH coating was consisted of three components: carbon layer, SiC nanowires and Na-doped carbonated hydroxyapatite. The carbon layer provided a dense and uniform surface structure for the growth of SiC nanowires. The SiC nanowires exhibited a porous structure, favoring the infiltration of Na-doped carbonated hydroxyapatite crystals. The Na-doped carbonated hydroxyapatite could infiltrate into the pores of SiC nanowires and finally cover the SiC nanowires entirely with a needle shape. The osteoblast-like MG63 cells were employed to assess the in vitro biocompatibility of the CSH coating. The MG63 cells favorably spread and grew well across the CSH coating surface with plenty of filopods and microvilli, exhibiting excellent cell activity. Moreover, the CSH coating elicited higher cell proliferation as compared to bare carbon/carbon composites. In conclusion, the CSH offers great potential as a coating material for future medical application in hard tissue replacement

Preparation and characterization of carbon/SiC nanowire/Na-doped carbonated hydroxyapatite multilayer coating for carbon/carbon composites

Energy Technology Data Exchange (ETDEWEB)

Leilei, Zhang, E-mail: zhangleilei1121@aliyun.com; Hejun, Li; Kezhi, Li; Shouyang, Zhang; Qiangang, Fu; Yulei, Zhang; Jinhua, Lu; Wei, Li

2014-09-15

Highlights: • CSH coatings were prepared by combination of magnetron sputter ion plating, CVD and UECD. • Na{sup +} and CO{sub 3}{sup 2−} were developed to co-substitute hydroxyapatite. • SiC nanowires were introduced into Na-doped carbonated hydroxyapatite. • CSH coatings showed excellent cell activity and cell proliferation behavior. - Abstract: A carbon/SiC nanowire/Na-doped carbonated hydroxyapatite multilayer coating (CSH coating) was prepared on carbon/carbon composites using a combination method of magnetron sputter ion plating, chemical vapor deposition and ultrasound-assisted electrochemical deposition procedure. The morphology, microstructure and chemical composition of the coating were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The results showed that the CSH coating was consisted of three components: carbon layer, SiC nanowires and Na-doped carbonated hydroxyapatite. The carbon layer provided a dense and uniform surface structure for the growth of SiC nanowires. The SiC nanowires exhibited a porous structure, favoring the infiltration of Na-doped carbonated hydroxyapatite crystals. The Na-doped carbonated hydroxyapatite could infiltrate into the pores of SiC nanowires and finally cover the SiC nanowires entirely with a needle shape. The osteoblast-like MG63 cells were employed to assess the in vitro biocompatibility of the CSH coating. The MG63 cells favorably spread and grew well across the CSH coating surface with plenty of filopods and microvilli, exhibiting excellent cell activity. Moreover, the CSH coating elicited higher cell proliferation as compared to bare carbon/carbon composites. In conclusion, the CSH offers great potential as a coating material for future medical application in hard tissue replacement.

75 FR 17756 - Blackstone River Valley National Heritage Corridor Commission: Notice of Meeting

Science.gov (United States)

2010-04-07

... DEPARTMENT OF THE INTERIOR Office of the Secretary Blackstone River Valley National Heritage..., United States Code, that a meeting of the John H. Chafee Blackstone River Valley National Heritage... the meeting to: Jan H. Reitsma, Executive Director, John H. Chafee, Blackstone River Valley National...

Traditional and modern crossing process exchange in a Buddhist–Muslim society. Case studied: Zangskar valley in the great Indian Himalayas

Directory of Open Access Journals (Sweden)

Salome Deboos

2017-04-01

Full Text Available Economic exchange in the Zangskar valley (in the high Indian Himalayas was a tightly integrated element of the social and political network of this Buddhist–Muslim society . Accordingly people of the lower stratum could not take part in the exchange and circulation of wealth coming from farming; the only way to have a role in the circulation of goods is by using cash. Since 1970, paid civil servants and the development of tourism and facilities have opened up cash exchange. Nowadays being able to procure manufactured goods by integrating into the Indian monetary exchange system has become synonymous with social success. Based on an ethnographical study carried out since 2000, this article proposes to show how the use of goods and green or stamped money for economic exchange impacts on and is impacted by the religious diversity of the population of Zangskar, which is not immune to influences emanating from the wider social, political and economic environment.

Dephasing and hyperfine interaction in carbon nanotubes double quantum dots

DEFF Research Database (Denmark)

Reynoso, Andres Alejandro; Flensberg, Karsten

2012-01-01

We study theoretically the return probability experiment, which is used to measure the dephasing time T-2*, in a double quantum dot (DQD) in semiconducting carbon nanotubes with spin-orbit coupling and disorder-induced valley mixing. Dephasing is due to hyperfine interaction with the spins of the C...... with these for DQDs in clean nanotubes, whereas the disorder effect is always relevant when the magnetic field is perpendicular to the nanotube axis....

The Great Recession was not so Great

NARCIS (Netherlands)

van Ours, J.C.

2015-01-01

The Great Recession is characterized by a GDP-decline that was unprecedented in the past decades. This paper discusses the implications of the Great Recession analyzing labor market data from 20 OECD countries. Comparing the Great Recession with the 1980s recession it is concluded that there is a

West Valley Demonstration Project Annual Site Environmental Report Calendar Year 2004

Energy Technology Data Exchange (ETDEWEB)

West Valley Nuclear Services Company (WVNSCO) and URS Group, Inc.

2005-09-30

Annual Site Environmental Report for the West Valley Demonstration Project (WVDP) for Calendar Year 2004. The report summarizes the environmental protection program at the West Valley Demonstration Project for CY 2004.

West Valley Demonstration Project Annual Site Environmental Report Calendar Year 2004

International Nuclear Information System (INIS)

2005-01-01

Annual Site Environmental Report for the West Valley Demonstration Project (WVDP) for Calendar Year 2004. The report summarizes the environmental protection program at the West Valley Demonstration Project for CY 2004

Morphological and compositional engineering of Ni/carbon ...

Indian Academy of Sciences (India)

Ni/multi-walled carbon nanotubes (MWCNTs) composite films were deposited on the glassy carbon electrode (GCE) by a Ni plating bath containing homogeneously dispersed MWCNTs using polyvinylpyrrolidone (PVP) as dispersion additive. Incorporation of MWCNTs into Ni matrix was greatly enhanced by the application ...

Infill of tunnel valleys associated with landward‐flowing ice sheets

DEFF Research Database (Denmark)

Moreau, Julien; Huuse, Mads

2014-01-01

The southern termination of the Middle and Late Pleistocene Scandinavian ice sheets was repeatedly located in the southern North Sea (sNS) and adjacent, north-sloping land areas. Giant meltwater-excavated valleys (tunnel valleys) formed at the southern termination of the ice sheets and contain...

Carbon cycle history through the Middle Jurassic (Aalenian – Bathonian of the Mecsek Mountains, Southern Hungary

Directory of Open Access Journals (Sweden)

Price Gregory D.

2018-04-01

Full Text Available A carbonate carbon isotope curve from the Aalenian–Bathonian interval is presented from the Óbánya valley, of the Mecsek Mountains, Hungary. This interval is certainly less well constrained and studied than other Jurassic time slices. The Óbánya valley lies in the eastern part of the Mecsek Mountains, between Óbánya and Kisújbánya and provides exposures of an Aalenian to Lower Cretaceous sequence. It is not strongly affected by tectonics, as compared to other sections of eastern Mecsek of the same age. In parts, a rich fossil assemblage has been collected, with Bathonian ammonites being especially valuable at this locality. The pelagic Middle Jurassic is represented by the Komló Calcareous Marl Formation and thin-bedded limestones of the Óbánya Limestone Formation. These are overlain by Upper Jurassic siliceous limestones and radiolarites of the Fonyászó Limestone Formation. Our new data indicate a series of carbon isotope anomalies within the late Aalenian and early-middle Bajocian. In particular, analysis of the Komló Calcareous Marl Formation reveals a negative carbon isotope excursion followed by positive values that occurs near the base of the section (across the Aalenian–Bajocian boundary. The origin of this carbon-isotope anomaly is interpreted to lie in significant changes to carbon fluxes potentially stemming from reduced run off, lowering the fertility of surface waters which in turn leads to lessened primary production and a negative δ13C shift. These data are comparable with carbonate carbon isotope records from other Tethyan margin sediments. Our integrated biostratigraphy and carbon isotope stratigraphy enable us to improve stratigraphic correlation and age determination of the examined strata. Therefore, this study of the Komló Calcareous Marl Formation confirms that the existing carbon isotope curves serve as a global standard for Aalenian–Bathonian δ13C variation.

Glacial geology of the upper Wairau Valley, Marlborough, New Zealand

International Nuclear Information System (INIS)

McCalpin, J.P.

1992-01-01

Late Pleistocene glaciers in the upper Wairau Valley deposited four groups of moraines inferred to represent one Waimean ice advance, two Otiran ice advances, and an advance of early Aranuian age. The Waimean and early Otiran glaciers advanced into Tarndale Valley, deposited terminal moraines, and shed outwash down both the Alma River and Travellers Valley. The middle Otiran glacier terminated in northern Tarndale Valley and shed outwash from the southern part of its terminus down the Alma River. The north side of the terminus abutted a large ice-dammed lake in the Wairau Gorge, and fan-deltas graded to an old shore level at an elevation of 1040 m. Well-preserved moraines at the mouths of four glaciated tributaries may be middle Otiran recessional, or late Otiran terminal moraines. The latest ice advance extended 11 km down the upper Wairau Valley and deposited a subdued moraine at Island Gully. The composite chronology of the latest glacial advance based on 10 radiocarbon ages suggests it occurred between about 9.5 and 10.2 ka. This age span is similar to that of early Aranuian glacial advances dated by other workers in the Southern Alps, and may reflect Younger Dryas cooling. (author). 22 refs., 10 figs., 3 tabs

Atmospheric Profiles of Carbon Dioxide Obtained with a UAS: Constraints on Square Kilometre Scale Carbon Budgets

Science.gov (United States)

Kunz, M.; Lavric, J. V.; Grant, R. H.; Gerbig, C.; Heimann, M.; Flatt, J. E.; Zeeman, M. J.; Wolf, B.

2016-12-01

The exchange of carbon between biosphere and atmosphere is a topic of high interest, particularly because the magnitude of biospheric climate feedback is uncertain. Soil chambers and eddy covariance systems, the traditional tools for the measurement of exchange fluxes, are subject to inherent limitations: chambers cover only small areas of typically less than on square meter, and eddy covariance is not applicable under very low wind conditions. Complementary methods can help to deal with these limitations and provide more confidence in up-scaling. During the ScaleX 2016 campaign an ecosystem was studied with a combination of multiple measurement approaches, including soil chambers, an eddy covariance station, a weather station, quasi-continuous CO2 measurements on a 10 m tower, multiple UAS with different sensors and remote sensing of temperature, humidity and wind profiles. The campaign took place at Fendt in Southern Germany on a flat valley floor covered by grass. We deployed COCAP, a compact carbon dioxide analyser for airborne platforms developed at the Max Planck Institute for Biogeochemistry in Jena, on a commercial multicopter (DJI S1000). COCAP measures carbon dioxide dry air mole fraction to an accuracy of 2 ppm as well as ambient pressure, temperature and relative humidity. At a total mass of 1 kg it contains a GPS receiver, on-board data logging capabilities and a radio transmitter which allows for real-time data visualisation on a ground station computer. In consecutive vertical profile measurements at night-time, reaching up to a maximum height of 150 m, we see a strong build-up of CO2 close to the ground which we attribute to exchange fluxes from the surface into the atmosphere that are trapped below a nocturnal inversion. We estimate these fluxes from the change in observed column amount of CO2 over time and compare our results to other methods. Challenges in the measurement and data analysis as well as the influence of wind, rotor downwash and

The great carbon push-pull: where science is pushing and policy is pulling the official forest carbon inventory of the US

Science.gov (United States)

C.W. Woodall; G.M. Domke; J. Coulston; M.B. Russell; J.A. Smith; C.H. Perry; S. Healey; A. Gray

2015-01-01

A national system of field inventory plots (FIA) is the primary data source for the annual assessment of US forest carbon (C) stocks and stock-change to meet reporting requirements under the United Nations Framework Convention on Climate Change (UNFCCC). The inventory data and their role in national carbon reporting continue to evolve. The framework of the previous C...

Carbon and water fluxes above a cacao plantation in Sulawesi, Indonesia

Science.gov (United States)

Falk, U.; Ibrom, A.

2003-04-01

The investigation of interactions between biosphere and atmosphere of the major land use types of the tropical rain forest margin area in South East Asia and quantification of the impact that land use change from undisturbed primary rain forest to pasture has on these interactions is task of subprogramme B1 within the DFG-funded project STORMA (Stability of Rain Forest Margins). In order to fulfill the projects tasks the different major land use types have to be investigated and each ecosystem characterized one by one and compared to a reference site in an undisturbed primary rain forest, to see the changes in the atmosphere-biospheric interactions, i. e. in water and carbon household, with land use change and thus the impact on regional climate. One of the major land use types in the valleys around the Lore Lindu National Park on Sulawesi are Cacao plantations, Theobroma cacao. A site in the Palolo valley near the village Nopu was chosen as research site since the area there is covered with small Cacao fields which form to one big area of Cacao and matches the requirements of the applied research approach. Since Cacao trees need to be shaded especially when younger, shadow trees had been planted and trees of the former forest had been left standing to serve as wind breaks and sun shades. The plantations in Nopu, Palolo valley, consist not only of fields of cultivated Cacao, but also serve as environment and home to the farmers and their families. The whole area of Cacao plantation is interspersed with wooden farm houses, which are also sources of carbon dioxide due to cooking or small power plants etc. and thus have to be taken into account when looking at the carbon household of this specific ecosystem. An estimation of the components of the carbon and water household and the contribution of the humans living within this environment to the carbon household of Cacao plantations of this ecosystem is subject of this presentation. From December 2001 until April 2002

Digital Elevation Model (DEM) file of topographic elevations for the Death Valley region of southern Nevada and southeastern California processed from US Geological Survey 1-degree Digital Elevation Model data files

International Nuclear Information System (INIS)

Turner, A.K.; D'Agnese, F.A.; Faunt, C.C.

1996-01-01

Elevation data have been compiled into a digital data base for an ∼100,000-km 2 area of the southern Great Basin, the Death Valley region of southern Nevada, and SE Calif., located between lat 35 degree N, long 115 degree W, and lat 38 degree N, long 118 degree W. This region includes the Nevada Test Site, Yucca Mountain, and adjacent parts of southern Nevada and eastern California and encompasses the Death Valley regional ground-water system. Because digital maps are often useful for applications other than that for which they were originally intended, and because the area corresponds to a region under continuing investigation by several groups, these digital files are being released by USGS

A comparative study of modern carbonate mud in reefs and carbonate platforms: Mostly biogenic, some precipitated

Science.gov (United States)

Gischler, Eberhard; Dietrich, Sarah; Harris, Daniel; Webster, Jody M.; Ginsburg, Robert N.

2013-06-01

Carbonate mud from reefs and carbonate platforms in six locations of the Atlantic, Indian, and Pacific Oceans (Belize, Bahamas, Florida, the Maldives, French Polynesia, Great Barrier Reef) was systematically and quantitatively analyzed with regard to texture, composition, mineralogy, and geochemistry. Mud composition shows considerable variability, however, the data supports the contention that these muds are largely derived from the breakdown of skeletal grains and codiacean algae. Only mud from the Bahamas and northern Belize, areas which are characterized by common whitings, is interpreted to be mainly inorganically precipitated. Three grain-size fractions (63-20 μm, 20-4 μm, aragonite needles, nanograins, and coccoliths. Coccoliths are common in deeper lagoonal settings of the open ocean settings (Maldives, French Polynesia). The geochemistry of the aragonite contents and strontium concentrations, suggesting physico-chemical precipitation. The northern Belize and Great Barrier Reef samples show the highest magnesium calcite values and, accordingly, produced the lowest aragonite and strontium measurements. The high-magnesium calcite portion of the northern Belize mud is either precipitated or due to abundant micritized skeletal grains (e.g., foraminifera): more studies are needed to verify the origin. In the case of the Great Barrier Reef sample, coralline algae appear to be the source of abundant high-magnesium calcite. This study emphasizes that from a global perspective, modern muds in reefs and carbonate platforms exhibit different compositions but are in many cases biologically derived. Even though the composition of modern carbonate muds varies among the six locations investigated, they may serve as analogs for the formation of muds in Cenozoic and Mesozoic reefs and carbonate platforms. Limitations of the interpretation of carbonate-mud origin include the difficulty of identifying, quantifying, and analyzing small grains, the ease with which small

Landform Evolution of the Zanskar Valley, Ladakh Himalaya.

Science.gov (United States)

Chahal, P.; Kumar, A.; Sharma, P.; Sundriyal, Y.; Srivastava, P.

2017-12-01

Zanskar River flow from south-west to north-east, perpendicularly through Higher Himalayan crystalline sequences, Tethyan sedimentary sequences, and Indus Molasses; and finally merge with the Indus River at Nimu. Geologically, the Indus valley is bounded by Ladakh Batholith in the north and highly folded and thrusted Zanskar mountain ranges in the south. Sedimentary sequences of Zanskar ranges are largely of continental origin, which were uplifted and deformed via several north verging thrusts, where Zanskar counter thrust, Choksti and Indus-Bazgo thrusts are important thrust zone, and there is atleast 36 km of crustal shortening in the Zanskar section which continued from middle Miocene to the late Pleistocene. This shortening is accommodated mainly by north or north-east directed Zanskar backthrusts. Two major tributaries of Zanskar: Tsrapchu and Doda, flow in the headwaters, along the strike of South Tibetan Detachment System (STDs), an east-west trending regional fault. The present study incorporate field sedimentology, geomorphology and chronology of landform associated with Zanskar valley. In the upper Zanskar, alluvial fan, valley fill and strath terraces configured the major landforms with paleo-lake deposits­­­ in the area between the fans. The lower catchment, at the confluence of Zanskar and Indus rivers, exhibit mainly valley fill terraces and strath terraces. Chronology suggests diachronous aggradation in the upper and lower Zanskar catchments. In the upper Zanskar large scale valley aggradation took place with simultaneously fan progradation and flooding events from 45-15 ka. Luminescence chronology of the lower Zanskar indicates aggradation from 145-55 ka and 18-12 ka. The two aggradation basins are separated by a deep V-shaped gorge which is approximately 60 km long. The longitudinal profile of the Zanskar River shows several local convexities marking knick point zone, which suggests tectonically controlled topography.

A proposal of conceptual model for Pertuso Spring discharge evaluation in the Upper Valley of Aniene River

Directory of Open Access Journals (Sweden)

Giuseppe Sappa

2016-10-01

Full Text Available The Upper Aniene River basin is part of a large karst aquifer, which interacts with the river, and represents the most important water resource in the southeast part of Latium Region, Central Italy, used for drinking, agriculture and hydroelectric supplies. This work provides hydrogeochemical data and their interpretations for 1 spring and 2 cross section of Aniene River, monitored from July 2014 to December 2015, in the Upper Valley of Aniene River, to identify flow paths and hydrogeochemical processes governing groundwater-surface water interactions in this region. These activities deal with the Environmental Monitoring Plan made for the catchment work project of the Pertuso Spring, in the Upper Valley of Aniene River, which is going to be exploited to supply an important drinking water network in the South part of Rome district. Discharge measurements and hydrogeochemical data were analyzed to develop a conceptual model of aquifer-river interaction, with the aim of achieving proper management and protection of this important hydrogeological system. All groundwater samples are characterized as Ca-HCO3 type. Geochemical modeling and saturation index computation of the water samples show that groundwater and surface water chemistry in the study area was evolved through the interaction with carbonate minerals. All groundwater samples were undersaturated with respect to calcite and dolomite, however some of the Aniene River samples were saturated with respect to dolomite. The analysis of Mg2+/Ca2+ ratios indicates that the dissolution of carbonate minerals is important for groundwater and surface water chemistry, depending on the hydrological processes, which control the groundwater residence time and chemical equilibria in the aquifer.

Some Environmental Issues of Inland Valleys: A Case Study | Asiam ...

African Journals Online (AJOL)

The study concluded that inland valleys can be real environmental liability because produce from such valleys can be polluted and hence can be a source of social conflict particularly when they fringe mineral concessions as the adverse impacts could be unfortunately attributed to mining activity and similar land uses.

Chapter 2. Assessment of undiscovered conventional oil and gas resources--Upper Jurassic-Lower Cretaceous Cotton Valley group, Jurassic Smackover interior salt basins total petroleum system, in the East Texas basin and Louisiana-Mississippi salt basins provinces.

Science.gov (United States)

Dyman, T.S.; Condon, S.M.

2006-01-01

The Jurassic Smackover Interior Salt Basins Total Petroleum System is defined for this assessment to include (1) Upper Jurassic Smackover Formation carbonates and calcareous shales and (2) Upper Jurassic and Lower Cretaceous Cotton Valley Group organic-rich shales. The Jurassic Smackover Interior Salt Basins Total Petroleum System includes four conventional Cotton Valley assessment units: Cotton Valley Blanket Sandstone Gas (AU 50490201), Cotton Valley Massive Sandstone Gas (AU 50490202), Cotton Valley Updip Oil and Gas (AU 50490203), and Cotton Valley Hypothetical Updip Oil (AU 50490204). Together, these four assessment units are estimated to contain a mean undiscovered conventional resource of 29.81 million barrels of oil, 605.03 billion cubic feet of gas, and 19.00 million barrels of natural gas liquids. The Cotton Valley Group represents the first major influx of clastic sediment into the ancestral Gulf of Mexico. Major depocenters were located in south-central Mississippi, along the Louisiana-Mississippi border, and in northeast Texas. Reservoir properties and production characteristics were used to identify two Cotton Valley Group sandstone trends across northern Louisiana and east Texas: a high-permeability blanket-sandstone trend and a downdip, low-permeability massive-sandstone trend. Pressure gradients throughout most of both trends are normal, which is characteristic of conventional rather than continuous basin-center gas accumulations. Indications that accumulations in this trend are conventional rather than continuous include (1) gas-water contacts in at least seven fields across the blanket-sandstone trend, (2) relatively high reservoir permeabilities, and (3) high gas-production rates without fracture stimulation. Permeability is sufficiently low in the massive-sandstone trend that gas-water transition zones are vertically extensive and gas-water contacts are poorly defined. The interpreted presence of gas-water contacts within the Cotton Valley

Parking Space Occupancy at Rail Stations in Klang Valley

Directory of Open Access Journals (Sweden)

Ho Phooi Wai

2017-01-01

Full Text Available The development of Klang Valley Integrated Rapid Transit system in Klang Valley, Malaysia has been quickly gaining momentum during the recent years. There will be two new MRT lines (MRT Line 1 and MRT Line 2 and one new LRT line (LRT Line 3 extended from the current integrated rail transit system by year 2020 with more than 90 new rail stations. With the substantial addition of potential rail passengers, there are doubts whether the existing Park and Ride facilities in Klang Valley are able to accommodate the future parking space demand at rail stations. This research studies the parking occupancy at various Park and Ride facilities in Klang Valley namely Taman Jaya, Asia Jaya, Taman Paramount, Taman Bahagia and Kelana Jaya by applying the non-conventional method utilizing Google Earth imageries. Results showed that the parking occupancy rate at these LRT stations were 100% or more before the commencement of LRT extension (Kelana Jaya and Ampang Lines in 2016 and in the range of 36% to 100% after the commencement of LRT extension due to the additionally built car parks and changes in parking pattern with dispersed passenger traffic.

Martian channels and valleys - Their characteristics, distribution, and age

Science.gov (United States)

Carr, M. H.; Clow, G. D.

1981-01-01

The distribution and ages of Martian channels and valleys, which are generally believed to have been cut by running water, are examined with particular emphasis on the small branching networks referred to as runoff channels or valley networks. Valleys at latitudes from 65 deg S to 65 deg N were surveyed on Viking images at resolutions between 125 and 300 m. Almost all of the valleys are found in the old cratered terrain, in areas characterized by high elevations, low albedos and low violet/red ratios. The networks are deduced to have formed early in the history of the planet, with a formation rate declining rapidly shortly after the decline of the cratering rate 3.9 billion years ago. Two types of outflow channels are distinguished: unconfined, in which broad swaths of terrain are scoured, and confined, in which flow is restricted to discrete channels. Both types start at local sources, and have formed episodically throughout Martian history. Fretted channels, found mainly in two latitude belts characterized by relatively rapid erosion along escarpments, are explained by the lateral enlargement of other channels by mass wasting.

Reporting on nuclear power: the Tennessee Valley case

International Nuclear Information System (INIS)

Shapley, D.

1977-01-01

The Tennessee Valley Authority (TVA), by deciding to have 90 percent of its new generating capacity nuclear, has made the valley a testing ground for civilian nuclear power, but valley newspapers have not provided consumers with enough information on either the pros or cons. A 1975 Browns Ferry plant fire, the most serious in the history of the civilian nuclear industry, prompted some nuclear critics to question TVA's competence to plan and manage the program. Newspapers carried wire-service stories of the fire, while their editorials gave strong support to TVA and the effort to reopen the plant. Valley newspapers have traditionally favored TVA as a powerful economic and political force which has brought many benefits. Local pride in the Oak Ridge Laboratory and plant facilities and the Federal fast-breeder reactor project headquarters also enhanced the positive attitude of the press, which tended to report details but not question nuclear safety or TVA ability. Newspapers have also failed to question TVA's claims that rates will decline as nuclear plants begin operating. A review of relevant news stories during the 1975--1976 period addresses the press coverage and notes its failure to question whether power demands justify TVA's plant construction program. Knowledgeable consultants are available to provide information on the issues, while editors are advised to give comprehensive, critical coverage and avoid promotion

Decision analysis framing study; in-valley drainage management strategies for the western San Joaquin Valley, California

Science.gov (United States)

Presser, Theresa S.; Jenni, Karen E.; Nieman, Timothy; Coleman, James

2010-01-01

Constraints on drainage management in the western San Joaquin Valley and implications of proposed approaches to management were recently evaluated by the U.S. Geological Survey (USGS). The USGS found that a significant amount of data for relevant technical issues was available and that a structured, analytical decision support tool could help optimize combinations of specific in-valley drainage management strategies, address uncertainties, and document underlying data analysis for future use. To follow-up on USGS's technical analysis and to help define a scientific basis for decisionmaking in implementing in-valley drainage management strategies, this report describes the first step (that is, a framing study) in a Decision Analysis process. In general, a Decision Analysis process includes four steps: (1) problem framing to establish the scope of the decision problem(s) and a set of fundamental objectives to evaluate potential solutions, (2) generation of strategies to address identified decision problem(s), (3) identification of uncertainties and their relationships, and (4) construction of a decision support model. Participation in such a systematic approach can help to promote consensus and to build a record of qualified supporting data for planning and implementation. In December 2008, a Decision Analysis framing study was initiated with a series of meetings designed to obtain preliminary input from key stakeholder groups on the scope of decisions relevant to drainage management that were of interest to them, and on the fundamental objectives each group considered relevant to those decisions. Two key findings of this framing study are: (1) participating stakeholders have many drainage management objectives in common; and (2) understanding the links between drainage management and water management is necessary both for sound science-based decisionmaking and for resolving stakeholder differences about the value of proposed drainage management solutions. Citing

Water-carbon Links in a Tropical Forest: How Interbasin Groundwater Flow Affects Carbon Fluxes and Ecosystem Carbon Budgets

Energy Technology Data Exchange (ETDEWEB)

Genereux, David [North Carolina State Univ., Raleigh, NC (United States); Osburn, Christopher [North Carolina State Univ., Raleigh, NC (United States); Oberbauer, Steven [Florida Intl Univ., Miami, FL (United States); Oviedo Vargas, Diana [North Carolina State Univ., Raleigh, NC (United States); Dierick, Diego [Florida Intl Univ., Miami, FL (United States)

2017-03-27

This report covers the outcomes from a quantitative, interdisciplinary field investigation of how carbon fluxes and budgets in a lowland tropical rainforest are affected by the discharge of old regional groundwater into streams, springs, and wetlands in the forest. The work was carried out in a lowland rainforest of Costa Rica, at La Selva Biological Station. The research shows that discharge of regional groundwater high in dissolved carbon dioxide represents a significant input of carbon to the rainforest "from below", an input that is on average larger than the carbon input "from above" from the atmosphere. A stream receiving discharge of regional groundwater had greatly elevated emissions of carbon dioxide (but not methane) to the overlying air, and elevated downstream export of carbon from its watershed with stream flow. The emission of deep geological carbon dioxide from stream water elevates the carbon dioxide concentrations in air above the streams. Carbon-14 tracing revealed the presence of geological carbon in the leaves and stems of some riparian plants near streams that receive inputs of regional groundwater. Also, discharge of regional groundwater is responsible for input of dissolved organic matter with distinctive chemistry to rainforest streams and wetlands. The discharge of regional groundwater in lowland surface waters has a major impact on the carbon cycle in this and likely other tropical and non-tropical forests.

BPA/Lower Valley transmission project. Final environmental impact statement

International Nuclear Information System (INIS)

1998-06-01

Bonneville Power Administration and Lower Valley Power and Light, Inc. propose to solve a voltage stability problem in the Jackson and Afton, Wyoming areas. Lower Valley buys electricity from BPA and then supplies it to the residences and businesses of the Jackson and Afton, Wyoming areas. BPA is considering five alternatives. For the Agency Proposed Action, BPA and Lower Valley would construct a new 115-kV line from BPA's Swan Valley Substation near Swan Valley in Bonneville County, Idaho about 58 km (36 miles) east to BPA's Teton Substation near Jackson in Teton County, Wyoming. The new line would be next to an existing 115-kV line. The Single-Circuit Line Alternative has all the components of the Agency Proposed Action except that the entire line would be supported by single-circuit wood pole H-frame structures. the Short Line Alternative has all the components of the Single-Circuit Line Alternative except it would only be half as long. BPA would also construct a new switching station near the existing right-of-way, west or north of Targhee Tap. Targhee Tap would then be removed. For the Static Var Compensation Alternative, BPA would install a Static Var Compensator (SVC) at Teton or Jackson Substation. An SVC is a group of electrical equipment placed at a substation to help control voltage on a transmission system. The No Action Alternative assumes that no new transmission line is built, and no other equipment is added to the transmission system

Selected constituents in the smokes of foreign commercial cigaretts: tar, nicotine, carbon monoxide, and carbon dioxide

Energy Technology Data Exchange (ETDEWEB)

Jenkins, R.A.; Quincy, R.B.; Guerin, M.R.

1979-05-01

The tar, nicotine, carbon monoxide, and carbon dioxide contents of the smokes of 220 brands of foreign commercial cigarettes are reported. In some instances, filter cigarettes of certain brands were found to deliver as much or more smoke constituents than their nonfilter counterparts. Also, data indicated that there can be a great variation in the tar, nicotine, or carbon monoxide content of the smoke of samples of a given brand of cigarettes, depending on the nation in which they are purchased. 24 tables.

Facile Synthesis of Coaxial CNTs/MnOx-Carbon Hybrid Nanofibers and Their Greatly Enhanced Lithium Storage Performance.

Science.gov (United States)

Yang, Zunxian; Lv, Jun; Pang, Haidong; Yan, Wenhuan; Qian, Kun; Guo, Tailiang; Guo, Zaiping

2015-12-01

Carbon nanotubes (CNTs)/MnOx-Carbon hybrid nanofibers have been successfully synthesized by the combination of a liquid chemical redox reaction (LCRR) and a subsequent carbonization heat treatment. The nanostructures exhibit a unique one-dimensional core/shell architecture, with one-dimensional CNTs encapsulated inside and a MnOx-carbon composite nanoparticle layer on the outside. The particular porous characteristics with many meso/micro holes/pores, the highly conductive one-dimensional CNT core, as well as the encapsulating carbon matrix on the outside of the MnOx nanoparticles, lead to excellent electrochemical performance of the electrode. The CNTs/MnOx-Carbon hybrid nanofibers exhibit a high initial reversible capacity of 762.9 mAhg(-1), a high reversible specific capacity of 560.5 mAhg(-1) after 100 cycles, and excellent cycling stability and rate capability, with specific capacity of 396.2 mAhg(-1) when cycled at the current density of 1000 mAg(-1), indicating that the CNTs/MnOx-Carbon hybrid nanofibers are a promising anode candidate for Li-ion batteries.

Vitrification facility at the West Valley Demonstration Project

International Nuclear Information System (INIS)

DesCamp, V.A.; McMahon, C.L.

1996-07-01

This report is a description of the West Valley Demonstration Project's vitrification facilities from the establishment of the West Valley, NY site as a federal and state cooperative project to the completion of all activities necessary to begin solidification of radioactive waste into glass by vitrification. Topics discussed in this report include the Project's background, high-level radioactive waste consolidation, vitrification process and component testing, facilities design and construction, waste/glass recipe development, integrated facility testing, and readiness activities for radioactive waste processing

Geomorphological characteristics of increased landslide activity in the Gudbrandsdalen valley, Norway

Science.gov (United States)

Heyerdahl, Håkon; Høydal, Øyvind

2016-04-01

The Gudbrandsdalen valley in Eastern Norway lies in a region where annual precipitation is generally low (down to 300 mm/year). The landslide activity has consequently historically been low, although the lower part of the valley sides generally is draped with thick layers of Quaternary deposits, primarily of glacial or glaciofluvial origin. The perception of natural hazards in the valley was previously primarily connected to flooding in the main river in the valley bottom during early summer, due to large discharges resulting from snowmelt in the mountainous regions west and east of the valley. However, several high-intensity events have changed the image of the region. Starting with a localized, but intense, landslide event in the Northern part of the valley in year 2008, two larger events covering almost the entire valley occurred in the years 2011 and 2013. A high number of landslides was triggered in all these events, including many flash floods and debris flows/debris slides in small and steep tributary rivers along the valley slopes. Landslide triggering covers different release mechanisms: In 2008, landslides were triggered without precipitation in not-frozen soil deposits without snow cover in the lower part of the valley. Groundwater flow through the permeable bedrock ("Otta schist") resulting from snow-melt in the elevated mountainous areas caused landslide triggering due to positive pore-water pressures forming at the bedrock surface below soil deposits, or at depressions in the terrain. Subsequent rainfall resulted in even more landslides being released. In later events (years 2011 and 2013) many landslides were caused by surface water taking new paths downslope, often due to man-made changes in existing waterways (typically poorly planned drainage solutions or new roads). Relatively small discharges in slopes with unconsolidated and easily erodible glacial deposits (typically lateral moraine) in many cases lead to small initial slides that down

Rift Valley fever potential mosquito vectors and their infection status ...

African Journals Online (AJOL)

Background: Rift Valley fever (RVF) is a mosquito-borne viral zoonotic disease. Rift Valley fever virus (RVFV) has been isolated from more than 40 species of mosquitoes from eight genera. This study was conducted to determine the abundance of potential mosquito vectors and their RVFV infection status in Ngorongoro ...

Groundwater budgets for Detrital, Hualapai, and Sacramento Valleys, Mohave County, Arizona, 2007-08

Science.gov (United States)

Garner, Bradley D.; Truini, Margot

2011-01-01

The United States Geological Survey, in cooperation with the Arizona Department of Water Resources, initiated an investigation of the hydrogeology and water resources of Detrital, Hualapai, and Sacramento Valleys in northwestern Arizona in 2005, and this report is part of that investigation. Water budgets were developed for Detrital, Hualapai, and Sacramento Valleys to provide a generalized understanding of the groundwater systems in this rural area that has shown some evidence of human-induced water-level declines. The valleys are within the Basin and Range physiographic province and consist of thick sequences of permeable alluvial sediment deposited into basins bounded by relatively less permeable igneous and metamorphic rocks. Long-term natural recharge rates (1940-2008) for the alluvial aquifers were estimated to be 1,400 acre-feet per year (acre-ft/yr) for Detrital Valley, 5,700 acre-ft/yr for Hualapai Valley, and 6,000 acre-ft/yr for Sacramento Valley. Natural discharge rates were assumed to be equal to natural recharge rates, on the basis of the assumption that all groundwater withdrawals to date have obtained water from groundwater storage. Groundwater withdrawals (2007-08) for the alluvial aquifers were less than 300 acre-ft/yr for Detrital Valley, about 9,800 acre-ft/yr for Hualapai Valley, and about 4,500 acre-ft/yr for Sacramento Valley. Incidental recharge from leaking water-supply pipes, septic systems, and wastewater-treatment plants accounted for about 35 percent of total recharge (2007-08) across the study area. Natural recharge and discharge values in this study were 24-50 percent higher than values in most previously published studies. Water budgets present a spatially and temporally "lumped" view of water resources and incorporate many sources of uncertainty in this study area where only limited data presently are available.

Diurnal cycle of air pollution in the Kathmandu Valley, Nepal: 2. Modeling results

Science.gov (United States)

Panday, Arnico K.; Prinn, Ronald G.; SchäR, Christoph

2009-11-01

After completing a 9-month field experiment studying air pollution and meteorology in the Kathmandu Valley, Nepal, we set up the mesoscale meteorological model MM5 to simulate the Kathmandu Valley's meteorology with a horizontal resolution of up to 1 km. After testing the model against available data, we used it to address specific questions to understand the factors that control the observed diurnal cycle of air pollution in this urban basin in the Himalayas. We studied the dynamics of the basin's nocturnal cold air pool, its dissipation in the morning, and the subsequent growth and decay of the mixed layer over the valley. During mornings, we found behavior common to large basins, with upslope flows and basin-center subsidence removing the nocturnal cold air pool. During afternoons the circulation in the Kathmandu Valley exhibited patterns common to plateaus, with cooler denser air originating over lower regions west of Kathmandu arriving through mountain passes and spreading across the basin floor, thereby reducing the mixed layer depth. We also examined the pathways of pollutant ventilation out of the valley. The bulk of the pollution ventilation takes place during the afternoon, when strong westerly winds blow in through the western passes of the valley, and the pollutants are rapidly carried out through passes on the east and south sides of the valley. In the evening, pollutants first accumulate near the surface, but then are lifted slightly when katabatic flows converge underneath. The elevated polluted layers are mixed back down in the morning, contributing to the morning pollution peak. Later in the morning a fraction of the valley's pollutants travels up the slopes of the valley rim mountains before the westerly winds begin.

Studies of geology and hydrology in the Basin and Range province, southwestern United States, for isolation of high-level radioactive waste-characterization of the Death Valley region, Nevada and California

International Nuclear Information System (INIS)

Bedinger, M.S.; Sargent, K.A.; Langer, W.H.

1989-01-01

The Death Valley region, Nevada and California, in the Basin and Range province, is an area of about 80,200 sq km located in southern Nevada and southeastern California. Precambrian metamorphic and intrusive basement rocks are overlain by a thick section of Paleozoic clastic and evaporitic sedimentary rocks. Mesozoic and Cenozoic rocks include extrusive and intrusive rocks and clastic sedimentary rocks. Structural features within the Death Valley indicate a long and complex tectonic evolution from late Precambrian to the present. Potential repository host media in the region include granite and other coarse-grained plutonic rocks, ashflow tuff, basaltic and andesitic lava flows, and basin fill. The Death Valley region is composed largely of closed topographic basins that are apparently coincident with closed groundwater flow systems. In these systems, recharge occurs sparingly at higher altitudes by infiltration of precipitation or by infiltration of ephemeral runoff. Discharge occurs largely by spring flow and by evaporation and transpiration in the playas. Death Valley proper, for which the region was named, is the ultimate discharge area for a large, complex system of groundwater aquifers that occupy the northeastern part of the region. The deepest part of the system consists of carbonate aquifers that connect closed topographic basins at depth. The discharge from the system occurs in several intermediate areas that are geomorphically, stratigraphically, and structurally controlled. Ultimately, most groundwater flow terminates by discharge to Death Valley; groundwater is discharged to the Colorado River from a small part of the region

PROFILE OF SOCIAL SERVICES FROM JIU VALLEY IN LIGHT PROFESSIONALS PERCEPTION. QUALITATIVE APPROACH

Directory of Open Access Journals (Sweden)

FELICIA ANDRIONI

2012-10-01

Full Text Available This study aims to analyse Jiu Valley social services profile using a qualitative perspective – focus grup analysis, by investigating perceptions of social services professionals from Jiu Valley, Hunedoara County, Romania. The qualitative methods of investigation, particularly important in achieving a comprehensive profile of social services from the Jiu Valley was to achieve a focused discussion sessions on social services. The following objectives were targeted by focus group: analysis of social professionals’ perception on social services from the Jiu Valley, Hunedoara County and identifying internal and external factors, to put their mark on the functioning of social services. Upon completion of discussions session focusing on social services in the Jiu Valley to conclude on the following aspects: social professionals perceive favorable development of social services in the Jiu Valley region in the period 2002-2008, and considering the dynamic development of these services is progressive. There are a number of elements which are seen by professionals as catalysts for the proper functioning and development of social services and factors inhibiting or blocking the functioning of these services.

Beaver-mediated lateral hydrologic connectivity, fluvial carbon and nutrient flux, and aquatic ecosystem metabolism

Science.gov (United States)

Wegener, Pam; Covino, Tim; Wohl, Ellen

2017-06-01

River networks that drain mountain landscapes alternate between narrow and wide valley segments. Within the wide segments, beaver activity can facilitate the development and maintenance of complex, multithread planform. Because the narrow segments have limited ability to retain water, carbon, and nutrients, the wide, multithread segments are likely important locations of retention. We evaluated hydrologic dynamics, nutrient flux, and aquatic ecosystem metabolism along two adjacent segments of a river network in the Rocky Mountains, Colorado: (1) a wide, multithread segment with beaver activity; and, (2) an adjacent (directly upstream) narrow, single-thread segment without beaver activity. We used a mass balance approach to determine the water, carbon, and nutrient source-sink behavior of each river segment across a range of flows. While the single-thread segment was consistently a source of water, carbon, and nitrogen, the beaver impacted multithread segment exhibited variable source-sink dynamics as a function of flow. Specifically, the multithread segment was a sink for water, carbon, and nutrients during high flows, and subsequently became a source as flows decreased. Shifts in river-floodplain hydrologic connectivity across flows related to higher and more variable aquatic ecosystem metabolism rates along the multithread relative to the single-thread segment. Our data suggest that beaver activity in wide valleys can create a physically complex hydrologic environment that can enhance hydrologic and biogeochemical buffering, and promote high rates of aquatic ecosystem metabolism. Given the widespread removal of beaver, determining the cumulative effects of these changes is a critical next step in restoring function in altered river networks.

West Valley facility spent fuel handling, storage, and shipping experience

International Nuclear Information System (INIS)

Bailey, W.J.

1990-11-01

The result of a study on handling and shipping experience with spent fuel are described in this report. The study was performed by Pacific Northwest Laboratory (PNL) and was jointly sponsored by the US Department of Energy (DOE) and the Electric Power Research Institute (EPRI). The purpose of the study was to document the experience with handling and shipping of relatively old light-water reactor (LWR) fuel that has been in pool storage at the West Valley facility, which is at the Western New York Nuclear Service Center at West Valley, New York and operated by DOE. A subject of particular interest in the study was the behavior of corrosion product deposits (i.e., crud) deposits on spent LWR fuel after long-term pool storage; some evidence of crud loosening has been observed with fuel that was stored for extended periods at the West Valley facility and at other sites. Conclusions associated with the experience to date with old spent fuel that has been stored at the West Valley facility are presented. The conclusions are drawn from these subject areas: a general overview of the West Valley experience, handling of spent fuel, storing of spent fuel, rod consolidation, shipping of spent fuel, crud loosening, and visual inspection. A list of recommendations is provided. 61 refs., 4 figs., 5 tabs

Geomorphic controls on Pleistocene knickpoint migration in Alpine valleys

Science.gov (United States)

Leith, Kerry; Fox, Matt; Moore, Jeffrey R.; Brosda, Julian; Krautblatter, Michael; Loew, Simon

2014-05-01

Recent insights into sub-glacial bedrock stress conditions suggest that the erosional efficiency of glaciers may reduce markedly following a major erosional cycle [Leith et al., 2013]. This implies that the formation of large glacial valleys within the Alps is likely to have occurred shortly after the onset of 100 ky glacial-interglacial cycles (at the mid-Pleistocene Revolution (MPR)). The majority of landscape change since this time may have therefore been driven by sub-aerial processes. This hypothesis is supported by observations of hillslope and channel morphology within Canton Valais (Switzerland), where major tributary valleys display a common morphology along their length, hinting at a shared geomorphic history. Glaciers currently occupy the headwaters of many catchments, while the upper reaches of rivers flow across extensive alluvial planes before abruptly transitioning to steep channels consisting of mixed bedrock and talus fan deposits. The rivers then converge to flow out over the alluvial plane of the Rhone Valley. Characteristically rough topographies within the region are suggested to mark the progressive transition from a glacial to fluvially-dominated landscape, and correlate well with steepened river channel sections determined from a 2.5 m resolution LiDAR DEM. We envisage a landscape in which ongoing tectonic uplift drives the emergence of Alpine bedrock through massive sedimentary valley infills (currently concentrated in the Rhone Valley), whose elevation is fixed by the consistent fluvial baselevel at Lake Geneva. As fluvial incision ceases at the onset of glaciation, continued uplift causes the formation of knickpoints at the former transition from bedrock to sedimentary infill. These knickpoints will then propagate upstream during subsequent interglacial periods. By investigating channel morphologies using an approach based on the steady-state form of the stream power equation, we can correlate steepened channel reaches (degraded

Metal Transport, Heavy Metal Speciation and Microbial Fixation Through Fluvial Subenvironments, Lower Coeur D'Alene River Valley, Idaho

Science.gov (United States)

Hooper, R. L.; Mahoney, J. B.

2001-12-01

The lower Coeur d'Alene River Valley of northern Idaho is the site of extensive lead and zinc contamination resulting from both direct riverine tailings disposal and flood remobilization of contaminated sediments derived from the Coeur d'Alene mining district upstream. Variations in the hydrologic regime, redox conditions, porosity/permeability, organic content and microbial activity results in complicated metal transport pathways. Documentation of these pathways is a prerequisite to effective remediation, and requires accurate analysis of lateral and vertical variations. An analytical approach combining sequential extraction, electron microscopy, and microanalysis provides a comprehensive assessment of particulate speciation in this complex hydrologic system. Rigorously controlled sample preparation and a new sequential extraction protocol provide unprecedented insight into the role of metal sequestration in fluvial subenvironments. Four subenvironments were investigated: bedload, overbank (levee), marsh, and lacustrine. Periodic floods remobilize primary ore minerals and secondary minerals from upstream tailings (primarily oxyhydroxides, sulfides and carbonates). The bedload in the lower valley is a reducing environment and acts as a sink for detrital carbonates and sulfides moving downstream. In addition, authigenic/biogenic Fe, Pb and Zn sulfides and phosphates are common in bedload sediments near the sediment/water interface. Flood redistribution of oxide, sulfide and carbonate phases results in periodic contaminant recharge generating a complex system of metal dissolution, mobilization, migration and precipitation. In levee environments, authigenic sulfides from flood scouring are quickly oxidized resulting in development of oxide coated grain surfaces. Stability of detrital minerals on the levee is variable depending on sediment permeability, grain size and mineralogy resulting in a complex stratigraphy of oxide zones mottled with zones dominated by detrital

Rod consolidation at the West Valley Demonstration Project

International Nuclear Information System (INIS)

Bailey, W.J.

1986-12-01

A rod consolidation demonstration with irradiated pressurized water reactor fuel was recently conducted by personnel from Nuclear Assurance Corporation and West Valley Nuclear Services Company at the West Valley Demonstration Project in West Valley, New York. The rod consolidation demonstration involved pulling all of the fuel rods from six fuel Assemblies. In general, the rod pulling proceeded smoothly. The highest compaction ratio attained was 1:8:1. Among the total of 1074 fuel rods were some known degraded rods (they had collapsed cladding, a result of in-reactor fuel densification), but no rods were broken or dropped during the demonstration. One aim was to gather information on the effect of rod consolidation operations on the integrity of the fuel rods during subsequent handling and storage. Another goal was to collect information on the condition and handling of intact, damaged, and failed fuel that has been in storage for an extended period. 9 refs., 8 figs., 1 tab

Salinity and resource management in the Hunter Valley

Energy Technology Data Exchange (ETDEWEB)

Creelman, R.A.; Cooke, R.; Simons, M. [RA Creelman & Associates (Australia)

1995-08-01

If excess water salinity is to be managed in the Hunter Valley, its causes and behaviour must be understood. Although Hunter Valley hydrology, hydrogeology and hydrogeochemistry require further study, there is now enough information available to begin the development of both temporal and spatial models as valley management tools. Currently the Department of Water Resources is developing a model known as Integrated Water Quality and Quantity Model (IQQM). IQQM which includes a salinity module is essentially a surface water simulation model. It wll enable testing of alternate management and operation policies such as the salinity property rights trading scheme recently introduced by the EPA to manage salt release from coal mines and power stations. An overview is presented of the progress made to date on the salinity module for IQQM, and an outline is given of the geological and hydrogeochemical concepts that have been assembled to support the salinity module of IQQM. 17 refs., 3 figs., 1 tab.

Hydrogeochemical investigations of groundwater in Ziarat valley, Baluchistan

International Nuclear Information System (INIS)

Akram, W.; Ahmad, M.; Rafiq, M.

2010-03-01

Present study was undertaken in Ziarat Valley, Baluchistan to investigate recent trends of groundwater chemistry (geochemical facies, geochemical evolution) and assess the groundwater quality for drinking and irrigation purposes. For this purpose samples of groundwater (open wells, tube wells, karezes, springs) were periodically collected from different locations and analyzed for dissolved chemical constituents such as sodium, potassium, magnesium, calcium, carbonate, bicarbonate, chloride and sulphate. The data indicated that concentrations of sodium, potassium, calcium and magnesium vary from 5 to 113,0.3 to 3,18 to 62 and 27 to 85 mg/l respectively. Values of anions i. e. bicarbonate, chloride and sulphate lie in the range of 184 to 418, 14 to 77 and 8 to 318 mg/l respectively. Hydrogeochemical facies revealed that groundwater in the study area belongs to Mg-HCO/sub 3/ type at 72% surveyed locations. Dissolution and calcite precipitation were found to be the main processes controlling the groundwater chemistry. Chemical quality was assessed for drinking use by comparing with WHO, Indian and proposed national standards, and for irrigation use using empirical indices such as SAR and RSC. The results show that groundwater is quite suitable for irrigation and drinking purposes. (author)

The Uncanny Valley and Nonverbal Communication in Virtual Characters

DEFF Research Database (Denmark)

Tinwell, Angela; Grimshaw, Mark Nicholas; Abdel Nabi, Debbie

2014-01-01

This chapter provides an overview of a current research project investigating the Uncanny Valley phenomenon in realistic, human-like virtual characters. !e research methods used in this Work include a retrospective of both empirical studies and philosophical writings on the Uncanny. No other...... research has explored the notion that realistic, human-like, virtual characters are regarded less favorably due to a perceived diminished degree of responsiveness in facial expression, specifically, nonverbal communication (NVC) in the upper face region. So far, this research project has provided the first...... empirical evidence to test the Uncanny Valley phenomenon in the domain of animated video game characters with speech, as opposed to just still, unresponsive images, as used in previous studies. Based on the results of these experiments, a conceptual framework of the Uncanny Valley in virtual characters has...

Generation of valley-polarized electron beam in bilayer graphene

International Nuclear Information System (INIS)

Park, Changsoo

2015-01-01

We propose a method to produce valley-polarized electron beams using a bilayer graphene npn junction. By analyzing the transmission properties of electrons through the junction with zigzag interface in the presence of trigonal warping, we observe that there exist a range of incident energies and barrier heights in which transmitted electrons are well polarized and collimated. From this observation and by performing numerical simulations, it is demonstrated that valley-dependent electronic currents with nearly perfect polarization can be generated. We also show that the peak-to-peak separation angle between the polarized currents is tunable either by incident energy or by barrier height each of which is controlled by using top and back gate voltages. The results can be used for constructing an electron beam splitter to produce valley-polarized currents

Generation of valley-polarized electron beam in bilayer graphene

Science.gov (United States)

Park, Changsoo

2015-12-01

We propose a method to produce valley-polarized electron beams using a bilayer graphene npn junction. By analyzing the transmission properties of electrons through the junction with zigzag interface in the presence of trigonal warping, we observe that there exist a range of incident energies and barrier heights in which transmitted electrons are well polarized and collimated. From this observation and by performing numerical simulations, it is demonstrated that valley-dependent electronic currents with nearly perfect polarization can be generated. We also show that the peak-to-peak separation angle between the polarized currents is tunable either by incident energy or by barrier height each of which is controlled by using top and back gate voltages. The results can be used for constructing an electron beam splitter to produce valley-polarized currents.

Vertical ozone transport in the Alps (VOTALP): the valley experiment 1996

Energy Technology Data Exchange (ETDEWEB)

Furger, M; Dommen, J; Graber, W K; Prevot, A; Poggio, L; Andreani, S; Keller, J; Portmann, W; Buerki, D; Erne, R; Richter, R; Tinguely, M [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-06-01

The EU project VOTALP started its valley campaign in the summer of 1996 in the Mesolcina valley. The influence of thermal circulations on ozone concentrations and on the exchange of ozone and its photochemical precursors between the valley atmosphere and the free troposphere above was the main focus of the study. PSI has participated with various measurement systems (conventional meteorological surface stations, radiosondes, scidar/DOAS systems, chemical analysers). An overview of PSI`s activities in the field campaign is given, and some preliminary results are presented. (author) 1 fig., 2 tabs., 2 refs.

75 FR 70020 - Central Valley Project Improvement Act, Water Management Plans

Science.gov (United States)

2010-11-16

... office on Central Valley Project water conservation best management practices that shall ``* * * develop... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Central Valley Project Improvement Act, Water Management Plans AGENCY: Bureau of Reclamation, Interior ACTION: Notice of Availability. SUMMARY: The...

76 FR 12756 - Central Valley Project Improvement Act, Water Management Plans

Science.gov (United States)

2011-03-08

... office on Central Valley Project water conservation best management practices that shall ``* * * develop... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Central Valley Project Improvement Act, Water Management Plans AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of availability. SUMMARY: The...

77 FR 64544 - Central Valley Project Improvement Act, Water Management Plans

Science.gov (United States)

2012-10-22

... Central Valley Project water conservation best management practices that shall ``develop criteria for... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Central Valley Project Improvement Act, Water Management Plans AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of availability. SUMMARY: The...

76 FR 18542 - Copper Valley Electric Association; Notice of Scoping Document 2 and Soliciting Scoping Comments...

Science.gov (United States)

2011-04-04

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 13124-002] Copper Valley.... Applicant: Copper Valley Electric Association (Copper Valley) d. Name of Project: Allison Creek Project. e.... 791(a)-825(r). g. Applicant Contact: Robert A. Wilkinson, CEO, Copper Valley Electric Association, P.O...

Electronic properties in a two-dimensional disordered electron liquid: Spin-valley interplay

International Nuclear Information System (INIS)

Burmistrov, I. S.; Chtchelkatchev, N. M.

2008-01-01

We report a detailed study of the influence of the spin and valley splittings on such physical observables of the two-dimensional disordered electron liquid as resistivity and spin and valley susceptibilities. We explain qualitatively the nonmonotonic dependence of the resistivity on temperature in the presence of a parallel magnetic field. In the presence of either spin or valley splitting we predict a temperature dependence of the resistivity with two maximum points

Superior Valley Polarization and Coherence of 2s Excitons in Monolayer WSe_{2}.

Science.gov (United States)

Chen, Shao-Yu; Goldstein, Thomas; Tong, Jiayue; Taniguchi, Takashi; Watanabe, Kenji; Yan, Jun

2018-01-26

We report the experimental observation of 2s exciton radiative emission from monolayer tungsten diselenide, enabled by hexagonal boron nitride protected high-quality samples. The 2s luminescence is highly robust and persists up to 150 K, offering a new quantum entity for manipulating the valley degree of freedom. Remarkably, the 2s exciton displays superior valley polarization and coherence than 1s under similar experimental conditions. This observation provides evidence that the Coulomb-exchange-interaction-driven valley-depolarization process, the Maialle-Silva-Sham mechanism, plays an important role in valley excitons of monolayer transition metal dichalcogenides.

Superior Valley Polarization and Coherence of 2 s Excitons in Monolayer WSe2

Science.gov (United States)

Chen, Shao-Yu; Goldstein, Thomas; Tong, Jiayue; Taniguchi, Takashi; Watanabe, Kenji; Yan, Jun

2018-01-01

We report the experimental observation of 2 s exciton radiative emission from monolayer tungsten diselenide, enabled by hexagonal boron nitride protected high-quality samples. The 2 s luminescence is highly robust and persists up to 150 K, offering a new quantum entity for manipulating the valley degree of freedom. Remarkably, the 2 s exciton displays superior valley polarization and coherence than 1 s under similar experimental conditions. This observation provides evidence that the Coulomb-exchange-interaction-driven valley-depolarization process, the Maialle-Silva-Sham mechanism, plays an important role in valley excitons of monolayer transition metal dichalcogenides.

78 FR 21414 - Central Valley Project Improvement Act, Water Management Plans

Science.gov (United States)

2013-04-10

... Valley Project Improvement Act, Water Management Plans AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of availability. SUMMARY: The following Water Management Plans are available for review... establish and administer an office on Central Valley Project water conservation best management practices...

76 FR 54251 - Central Valley Project Improvement Act, Water Management Plans

Science.gov (United States)

2011-08-31

... and administer an office on Central Valley Project water conservation best management practices that... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Central Valley Project Improvement Act, Water Management Plans AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of availability. SUMMARY: The...

75 FR 38538 - Central Valley Project Improvement Act, Water Management Plans

Science.gov (United States)

2010-07-02

... to establish and administer an office on Central Valley Project water conservation best management... DEPARTMENT OF THE INTERIOR Bureau of Reclamation Central Valley Project Improvement Act, Water Management Plans AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of availability. SUMMARY: The...

Virgin Valley opal district, Humboldt County, Nevada

Science.gov (United States)

Staatz, Mortimer Hay; Bauer, Herman L.

1951-01-01

The Virgin Valley opal district, Humboldt County, Nevada, is near the Oregon-Nevada border in the Sheldon Game Refuge. Nineteen claims owned by Jack and Toni Crane were examined, sampled, and tested radiometrically for uranium. Numerous discontinuous layers of opal are interbedded with a gently-dipping series of vitric tuff and ash which is at least 300 ft thick. The tuff and ash are capped by a dark, vesicular basalt in the eastern part of the area and by a thin layer of terrace qravels in the area along the west side of Virgin Valley. Silicification of the ash and tuff has produced a rock that ranges from partly opalized rock that resembles silicified shale to completely altered rock that is entirely translucent, and consists of massive, brown and pale-green opal. Carnotite, the only identified uranium mineral, occurs as fracture coatings or fine layers in the opal; in places, no uranium minerals are visible in the radioactive opal. The opal layers are irregular in extent and thickness. The exposed length of the layers ranges from 8 to 1, 200 ft or more, and the thickness of the layers ranges from 0. 1 to 3. 9 ft. The uranium content of each opal layer, and of different parts of the same layer, differs widely. On the east side of Virgin Valley four of the seven observed opal layers, nos. 3, 4, 5, and 7, are more radioactive than the average; and the uranium content ranges from 0. 002 to 0. 12 percent. Two samples, taken 5 ft apart across opal layer no. 7, contained 0. 003 and 0. -049 percent uranium. On the west side of the valley only four of the fifteen observed opal layers, nos; 9, , 10, 14, and 15, are more radioactive than the average; and the uranium content ranges from 0. 004 to 0. 047 percent. Material of the highest grade was found in a small discontinuous layer of pale-green opal (no. 4) on the east side of Virgin Valley. The grade of this layer ranged from 0. 027 to 0. 12 percent uranium.

77 FR 42722 - Copper Valley Electric Association; Notice of Updated Environmental Analysis Preparation Schedule

Science.gov (United States)

2012-07-20

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 13124-002] Copper Valley...: Original License Application. b. Project No.: 13124-002. c. Applicant: Copper Valley Electric Association (Copper Valley). d. Name of Project: Allison Creek Project. e. Location: On the south side of Port Valdez...

Velocity barrier-controlled of spin-valley polarized transport in monolayer WSe2 junction

Science.gov (United States)

Qiu, Xuejun; Lv, Qiang; Cao, Zhenzhou

2018-05-01

In this work, we have theoretically investigated the influence of velocity barrier on the spin-valley polarized transport in monolayer (ML) WSe2 junction with a large spin-orbit coupling (SOC). Both the spin-valley resolved transmission probabilities and conductance are strong dependent on the velocity barrier, as the velocity barrier decreases to 0.06, a spin-valley polarization of exceeding 90% is observed, which is distinct from the ML MoS2 owing to incommensurable SOC. In addition, the spin-valley polarization is further increased above 95% in a ML WSe2 superlattice, in particular, it's found many extraordinary velocity barrier-dependent transport gaps for multiple barrier due to evanescent tunneling. Our results may open an avenue for the velocity barrier-controlled high-efficiency spin and valley polarizations in ML WSe2-based electronic devices.

Aerial photographic interpretation of lineaments and faults in late Cenozoic deposits in the eastern parts of the Saline Valley 1:100, 000 quadrangle, Nevada and California, and the Darwin Hills 1:100, 000 quadrangle, California

International Nuclear Information System (INIS)

Reheis, M.C.

1991-01-01

Faults and fault-related lineaments in Quaternary and late Tertiary deposits in the southern part of the Walker Lane are potentially active and form patterns that are anomalous compared to those in most other areas of the Great Basin. Two maps at a scale of 1:100,000 summarize information about lineaments and faults in the area around and southwest of the Death Valley-Furnace Creek fault system based on extensive aerial-photo interpretation, limited field interpretation, limited field investigations, and published geologic maps. There are three major fault zones and two principal faults in the Saline Valley and Darwin Hills 1:100,000 quadrangles. (1) The Death Valley-Furnace Creek fault system and (2) the Hunter Mountain fault zone are northwest-trending right-lateral strike-slip fault zones. (3) The Panamint Valley fault zone and associated Towne Pass and Emigrant faults are north-trending normal faults. The intersection of the Hunter Mountain and Panamint Valley fault zones is marked by a large complex of faults and lineaments on the floor of Panamint Valley. Additional major faults include (4) the north-northwest-trending Ash Hill fault on the west side of Panamint Valley, and (5) the north-trending range-front Tin Mountain fault on the west side of the northern Cottonwood Mountains. The most active faults at present include those along the Death Valley-Furnace Creek fault system, the Tin Mountain fault, the northwest and southeast ends of the Hunter Mountain fault zone, the Ash Hill fault, and the fault bounding the west side of the Panamint Range south of Hall Canyon. Several large Quaternary landslides on the west sides of the Cottonwood Mountains and the Panamint Range apparently reflect slope instability due chiefly to rapid uplift of these ranges. 16 refs

Ground water in Dale Valley, New York

Science.gov (United States)

Randall, Allan D.

1979-01-01

Dale Valley is a broad valley segment, enlarged by glacial erosion, at the headwaters of Little Tonawanda Creek near Warsaw , New York. A thin, shallow alluvial aquifer immediately underlies the valley floor but is little used. A deeper gravel aquifer, buried beneath many feet of lake deposits, is tapped by several industrial wells. A finite-difference digital model treated the deep aquifer as two-dimensional with recharge and discharge through a confining layer. It was calibrated by simulating (1) natural conditions, (2) an 18-day aquifer test, and (3) 91 days of well-field operation. Streamflow records and model simulations suggest that in moderately wet years such as 1974, a demand of 750 gallons per minute could be met by withdrawal from the creek and from the aquifer without excessive drawdown at production wells or existing domestic wells. With reasonable but unverified model adjustments to simulate an unusually dry year, the model predicts that a demand of 600 gallons per minute could be met from the same sources. Water high in chloride has migrated from bedrock into parts of the deep aquifer. Industrial pumpage, faults in the bedrock, and the natural flow system may be responsible. (Woodard-USGS)

Increased body mass of ducks wintering in California's Central Valley

Science.gov (United States)

Fleskes, Joseph P.; Yee, Julie L.; Yarris, Gregory S.; Loughman, Daniel L.

2016-01-01

Waterfowl managers lack the information needed to fully evaluate the biological effects of their habitat conservation programs. We studied body condition of dabbling ducks shot by hunters at public hunting areas throughout the Central Valley of California during 2006–2008 compared with condition of ducks from 1979 to 1993. These time periods coincide with habitat increases due to Central Valley Joint Venture conservation programs and changing agricultural practices; we modeled to ascertain whether body condition differed among waterfowl during these periods. Three dataset comparisons indicate that dabbling duck body mass was greater in 2006–2008 than earlier years and the increase was greater in the Sacramento Valley and Suisun Marsh than in the San Joaquin Valley, differed among species (mallard [Anas platyrhynchos], northern pintail [Anas acuta], America wigeon [Anas americana], green-winged teal [Anas crecca], and northern shoveler [Anas clypeata]), and was greater in ducks harvested late in the season. Change in body mass also varied by age–sex cohort and month for all 5 species and by September–January rainfall for all except green-winged teal. The random effect of year nested in period, and sometimes interacting with other factors, improved models in many cases. Results indicate that improved habitat conditions in the Central Valley have resulted in increased winter body mass of dabbling ducks, especially those that feed primarily on seeds, and this increase was greater in regions where area of post-harvest flooding of rice and other crops, and wetland area, has increased. Conservation programs that continue to promote post-harvest flooding and other agricultural practices that benefit wintering waterfowl and continue to restore and conserve wetlands would likely help maintain body condition of wintering dabbling ducks in the Central Valley of California.

Estimation of Carbon Sink in Surface Carbonate Rocks of Guangxi Province by Using Remote Sensing Images

Science.gov (United States)

Jia, B.; Zhou, G.; Wang, H.; Yue, T.; Huang, W.

2018-04-01

Studies of the imbalance of source sinks in the carbon cycle show that CO2 absorbed during rock weathering is part of the "miss carbon" of the global carbon cycle. The carbon sink contribution of carbonate rocks obviously plays a very important role in the absorption of atmospheric CO2. Estimation of carbon sinks in karst dynamic system of Guangxi province has great significance for further understanding of global karst carbon cycle and global climate research. This paper quotes the rock data from Tao Xiaodong's paper, which is obtained using RS and GIS techniques. At the same time, the dissolution rate model studied by Zhou Guoqing and others was used to estimate the dissolution rate of carbonate rocks in Guangxi Province. Finally, the CO2 content consumed by carbonate karstification in Guangxi Province was 1342910.447 t a-1. The results obtained are in the same order of magnitude as the CO2 content consumed by carbonate rock karstification in Guangxi Province calculated by Tao Xiaodong.

Meie mees Silicon Valleys / Kertu Ruus

Index Scriptorium Estoniae

Ruus, Kertu, 1977-

2007-01-01

Ilmunud ka: Delovõje Vedomosti 5. dets. lk. 4. Peaminister Andrus Ansip avas Eesti Ettevõtluse Sihtasutuse esinduse Silicon Valley pealinnas San Joses. Vt. samas: Ränioru kliima on tehnoloogiasõbralik; Andrus Viirg

Coupled simulation of meteorological parameters and sound intensity in a narrow valley

Energy Technology Data Exchange (ETDEWEB)

Heimann, D. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere; Gross, G. [Hannover Univ. (Germany). Inst. fuer Meteorologie und Klimatologie

1997-07-01

A meteorological mesoscale model is used to simulate the inhomogeneous distribution of temperature and the appertaining development of thermal wind systems in a narrow two-dimensional valley during the course of a cloud-free day. A simple sound particle model takes up the simulated meteorological fields and calculates the propagation of noise which originates from a line source at one of the slopes of this valley. The coupled modeling system ensures consistency of topography, meteorological parameters and the sound field. The temporal behaviour of the sound intensity level across the valley is examined. It is only governed by the time-dependent meteorology. The results show remarkable variations of the sound intensity during the course of a day depending on the location in the valley. (orig.) 23 refs.

40 CFR 81.90 - Androscoggin Valley Interstate Air Quality Control Region.

Science.gov (United States)

2010-07-01

... Quality Control Region. 81.90 Section 81.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.90 Androscoggin Valley Interstate Air Quality Control Region. The Androscoggin Valley Interstate Air Quality Control Region (Maine-New Hampshire) consists of the territorial...

Ground-water quality in the southeastern Sacramento Valley aquifer, California, 1996

Science.gov (United States)

Milby Dawson, Barbara J.

2001-01-01

In 1996, the U.S. Geological Survey sampled 29 domestic wells and 2 monitoring wells in the southeastern Sacramento Valley as part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program. This area, designated as the NAWQA Sacramento subunit study area, was chosen because it had the largest amount of ground-water use in the Sacramento River Basin. The Sacramento subunit study area is about 4,400 square kilometers and includes intense agricultural and urban development. The wells sampled ranged from 14.9 to 79.2 meters deep. Ground-water samples from 31 wells were analyzed for 6 field measurements, 14 inorganic constituents, 6 nutrient constituents, organic carbon, 86 pesticides, 87 volatile organic compounds, tritium (hydrogen-3), radon-222, deuterium (hydrogen-2), and oxygen-18. Nitrate levels were lower than the 2000 drinking-water standards in all but one well, but many detections were in the range that indicated an effect by human activities on ground-water quality. Radon was detected in all wells, and was measured at levels above the proposed Federal 2000 maximum contaminant level in 90 percent of the wells. Five pesticides and one pesticide degradation product were detected in ground-water samples and concentrations were below 2000 drinking-water standards. All pesticides detected during this study have been used in the Sacramento Valley. Thirteen volatile organic compounds were detected in ground water. One detection of trichloroethene was above Federal 2000 drinking-water standards, and another, tetrachloromethane, was above California 1997 drinking-water standards; both occurred in a well that had eight volatile organic compound detections and is near a known source of ground-water contamination. Pesticides and volatile organic compounds were detected in agricultural and urban areas; both pesticides and volatile organic compounds were detected at a higher frequency in urban wells. Ground-water chemistry indicates that natural

Fully Valley/spin polarized current and Fano factor through the Graphene/ferromagnetic silicene/Graphene junction

Energy Technology Data Exchange (ETDEWEB)

Rashidian, Zeinab; Rezaeipour, Saeid [Department of Physics, Faculty of Science, Lorestan University, Lorestan (Iran, Islamic Republic of); Hajati, Yaser [Department of Physics, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz (Iran, Islamic Republic of); Lorestaniweiss, Zeinab, E-mail: rashidian1983z@gmail.com [Department of Physics, Faculty of Science, Lorestan University, Lorestan (Iran, Islamic Republic of); Ueda, Akiko [Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba (Japan)

2017-02-15

In this work, we study the transport properties of Dirac fermions through the ferromagnetic silicene which is sandwiched between the Graphene leads (G/FS/G). Spin/valley conductance, spin/valley polarization, and also Fano factor are theoretically calculated using the Landauer-Buttiker formula. We find that the fully valley and spin polarized currents through the G/FS/G junction can be obtained by increasing the electric field strength and the length of ferromagnetic silicene region. Moreover, the valley polarization can be tuned from negative to positive values by changing the electric field. We find that the Fano factor also changes with the spin and valley polarization. Our findings of high controllability of the spin and valley transport in such a G/FS/G junction the potential of this junction for spin-valleytronics applications.

Vegetation - San Felipe Valley [ds172

Data.gov (United States)

California Natural Resource Agency — This Vegetation Map of the San Felipe Valley Wildlife Area in San Diego County, California is based on vegetation samples collected in the field in 2002 and 2005 and...

Esophageal cancer in north rift valley of western Kenya | Wakhisi ...

African Journals Online (AJOL)

Esophageal cancer in north rift valley of western Kenya. ... Our finding also contrast with an earlier reported study that indicated that Rift Valley is a low prevalence area for this type of cancer. The mean age ... This may lead to identification of molecular biomarkers to be used in future for the early detection of this neoplasm.

Ethno-botanical study of medicinal plants of Paddar Valley of ...

African Journals Online (AJOL)

The Paddar Valley, historically known as Sapphire Valley situated in Kishtwar district, is a prime landmark in the Jammu region of J&K state and is known for its rich cultural and plant diversity because of diverse habitats such as rivers, streams, meadows and steep mountain slopes. The area is located in the dry temperate ...

Evidence for strong Holocene earthquake(s) in the Wabash Valley seismic zone

International Nuclear Information System (INIS)

Obermeier, S.

1991-01-01

Many small and slightly damaging earthquakes have taken place in the region of the lower Wabash River Valley of Indiana and Illinois during the 200 years of historic record. Seismologists have long suspected the Wabash Valley seismic zone to be capable of producing earthquakes much stronger than the largest of record (m b 5.8). The seismic zone contains the poorly defined Wabash Valley fault zone and also appears to contain other vaguely defined faults at depths from which the strongest earthquakes presently originate. Faults near the surface are generally covered with thick alluvium in lowlands and a veneer of loess in uplands, which make direct observations of faults difficult. Partly because of this difficulty, a search for paleoliquefaction features was begun in 1990. Conclusions of the study are as follows: (1) an earthquake much stronger than any historic earthquake struck the lower Wabash Valley between 1,500 and 7,500 years ago; (2) the epicentral region of the prehistoric strong earthquake was the Wabash Valley seismic zone; (3) apparent sites have been located where 1811-12 earthquake accelerations can be bracketed

Aburra Valley: Quo vadis?

International Nuclear Information System (INIS)

Hermelin, Michel

2008-01-01

These paper intents a brief description of the evolution that characterised natural risk prevention in the area surrounding the city of Medellin, Colombia, called the Aburra Valley. Both the lithological and structural composition of the Valle and its topographic and climatic conditions contribute to the abundance of destructive natural phenomena as earthquakes, slope movements, flash floods and, in a lower proportion, to floods. The population increase, which reaches now 3.5 millions inhabitants and the frequent occupation of sites exposed to natural hazards have resulted in numerous disasters. At present two entities called SIMPAD and DAPARD work on risk prevention, on city and department scale respectively. The amount of knowledge about physical environment is considered to be insufficient, together with regulations which should direct land use in accordance to restrictions related to natural hazards. Several seminars on this topic have already been carried out and the organisers of the present one, destined to commemorate the twentieth anniversary of the Villatina disaster, should make the decision to meet each two years. Furthermore, the creation of a permanent commission dedicated to study past events, to foster information broadcasting and to seek a better knowledge of the Aburra Valley, should be considered

Carbon emissions in China

International Nuclear Information System (INIS)

Liu, Zhu

2016-01-01

This study analyzes the spatial-temporal pattern and processes of China's energy-related carbon emissions. Based on extensive quantitative analysis, it outlines the character and trajectory of China's energy-related carbon emissions during the period 1995-2010, examining the distribution pattern of China's carbon emissions from regional and sectoral perspectives and revealing the driving factors of China's soaring emission increase. Further, the book investigates the supply chain carbon emissions (the carbon footprints) of China's industrial sectors. Anthropogenic climate change is one of the most serious challenges currently facing humankind. China is the world's largest developing country, top primary energy consumer and carbon emitter. Achieving both economic growth and environmental conservation is the country's twofold challenge. Understanding the status, features and driving forces of China's energy-related carbon emissions is a critical aspect of attaining global sustainability. This work, for the first time, presents both key findings on and a systematic evaluation of China's carbon emissions from energy consumption. The results have important implications for global carbon budgets and burden-sharing with regard to climate change mitigation. The book will be of great interest to readers around the world, as it addresses a topic of truly global significance.

Electron spin resonance and spin-valley physics in a silicon double quantum dot.

Science.gov (United States)

Hao, Xiaojie; Ruskov, Rusko; Xiao, Ming; Tahan, Charles; Jiang, HongWen

2014-05-14

Silicon quantum dots are a leading approach for solid-state quantum bits. However, developing this technology is complicated by the multi-valley nature of silicon. Here we observe transport of individual electrons in a silicon CMOS-based double quantum dot under electron spin resonance. An anticrossing of the driven dot energy levels is observed when the Zeeman and valley splittings coincide. A detected anticrossing splitting of 60 MHz is interpreted as a direct measure of spin and valley mixing, facilitated by spin-orbit interaction in the presence of non-ideal interfaces. A lower bound of spin dephasing time of 63 ns is extracted. We also describe a possible experimental evidence of an unconventional spin-valley blockade, despite the assumption of non-ideal interfaces. This understanding of silicon spin-valley physics should enable better control and read-out techniques for the spin qubits in an all CMOS silicon approach.

Cleanup criteria for the West Valley demonstration project

International Nuclear Information System (INIS)

Parrott, J.D.

1999-01-01

The US Nuclear Regulatory Commission (NRC) is prescribing decontamination and decommissioning (cleanup) criteria for the West Valley Demonstration Project and the West Valley, New York, site. The site is contaminated with various forms of residual radioactive contamination and contains a wide variety of radioactive waste. The NRC is planning to issue cleanup criteria for public comment in Fall 1999. Due to the complexity of the site, and the newness of NRC's cleanup criteria policy, applying NRC's cleanup criteria to this site will be an original regulatory undertaking. (author)

Spin- and valley-polarized one-way Klein tunneling in photonic topological insulators.

Science.gov (United States)

Ni, Xiang; Purtseladze, David; Smirnova, Daria A; Slobozhanyuk, Alexey; Alù, Andrea; Khanikaev, Alexander B

2018-05-01

Recent advances in condensed matter physics have shown that the spin degree of freedom of electrons can be efficiently exploited in the emergent field of spintronics, offering unique opportunities for efficient data transfer, computing, and storage ( 1 - 3 ). These concepts have been inspiring analogous approaches in photonics, where the manipulation of an artificially engineered pseudospin degree of freedom can be enabled by synthetic gauge fields acting on light ( 4 - 6 ). The ability to control these degrees of freedom significantly expands the landscape of available optical responses, which may revolutionize optical computing and the basic means of controlling light in photonic devices across the entire electromagnetic spectrum. We demonstrate a new class of photonic systems, described by effective Hamiltonians in which competing synthetic gauge fields, engineered in pseudospin, chirality/sublattice, and valley subspaces, result in bandgap opening at one of the valleys, whereas the other valley exhibits Dirac-like conical dispersion. We show that this effective response has marked implications on photon transport, among which are as follows: (i) a robust pseudospin- and valley-polarized one-way Klein tunneling and (ii) topological edge states that coexist within the Dirac continuum for opposite valley and pseudospin polarizations. These phenomena offer new ways to control light in photonics, in particular, for on-chip optical isolation, filtering, and wave-division multiplexing by selective action on their pseudospin and valley degrees of freedom.

Stratigraphy and uranium deposits, Lisbon Valley district, San Juan County, Utah

International Nuclear Information System (INIS)

Huber, G.C.

1980-01-01

Uranium occurrences are scattered throughout southeastern Utah in the lower sandstones of the Triassic Chinle Formation. The Lisbon Valley district, however, is the only area with uranium deposits of substantial size. The stratigraphy of the Lisbon Valley district was investigated to determine the nature of the relationship between the mineralized areas and the lower Chinle sandstones. The geochemistry of the Lisbon Valley uranium deposits indicates a possible district-wide zoning. Interpretation of the elemental zoning associated with individual ore bodies suggests that humates overtaken by a geochemical oxidation-reduction interface may have led to formation of the uranium deposits. Refs

Meie ingel Silicon Valleys / Raigo Neudorf

Index Scriptorium Estoniae

Neudorf, Raigo

2008-01-01

Ettevõtluse Arendamise Sihtasutuse esinduse töölepanekust USAs Silicon Valleys räägib esinduse juht Andrus Viirg. Vt. ka: Eestlasi leidub San Franciscos omajagu; Muljetavaldav karjäär; USAga ammune tuttav

Microbial terroir in Chilean valleys: Diversity of non-conventional yeast

Directory of Open Access Journals (Sweden)

Carla eJara

2016-05-01

Full Text Available In this study, the presence of non-conventional yeast associated with vineyards located between latitudes 30ºS and 36ºS was examined, including the valleys of Limarí, Casablanca, Maipo, Colchagua, Maule and Itata. The microbial fingerprinting in each valley was examined based on the specific quantification of yeast of enological interest. Grape berries were sampled to evaluate the presence and load of non-conventional yeast with enological potential, such as Metschnikowia, Hanseniaspora, Torulaspora, Debaryomyces, Meyerozyma and Rhodotorula. These yeasts were present in all vineyards studied but with varying loads depending on the valley sampled. No identical fingerprints were observed; however, similarities and differences could be observed among the microbial profiles of each valley. A co-variation in the loads of Metschnikowia and Hanseniaspora with latitude was observed, showing high loads in the Casablanca and Itata valleys, which was coincident with the higher relative humidity or rainfall of those areas. Non-conventional yeasts were also isolated and identified after sequencing molecular markers. Potentially good aromatic properties were also screened among the isolates, resulting in the selection of mostly Metschnikowia and Hanseniaspora isolates. Finally, our results suggest that microbial terroir might be affected by climatic conditions such as relative humidity and rainfall, especially impacting the load of non-conventional yeast. In this study, the microbial fingerprint for yeast in Chilean vineyards is reported for the first time revealing an opportunity to study the contribution of this assembly of microorganisms to the final product.

Reconstruction of the MSRs in-situ at Beaver Valley

International Nuclear Information System (INIS)

Yarden, A.; Tam, C.W.; Deahna, S.T.; McFeaters, C.V.

1992-01-01

The Moisture Separator Reheaters (MSRs) have been problem components at Beaver Valley 1 pressurized water reactor since the plant started up 16 years ago, many of the problems encountered being widespread in the nuclear industry. In 1991, Duquesne Light rebuilt the Beaver Valley 1 MSRs and in 1992 did the same at unit 2. The reconstruction projects have proved cost effective with short payback times and significant improvements in station performance. (Author)

EPA Region 1 - Map Layers for Valley ID Tool (Hosted Feature Service)

Data.gov (United States)

U.S. Environmental Protection Agency — The Valley Service Feature Layer hosts spatial data for EPA Region 1's Valley Identification Tool. These layers contain attribute information added by EPA R1 GIS...

Transient electromagnetic soundings in the San Luis Valley, Colorado, near the Great Sand Dunes National Park and Preserve and the Alamosa National Wildlife Refuge (field seasons 2007, 2009, and 2011)

Science.gov (United States)

Fitterman, David V.

2017-06-13

Transient electromagnetic (TEM) soundings were made in the San Luis Valley, Colorado, to map the location of a blue clay unit as well as to investigate the presence of suspected faults. A total of 147 soundings were made near and in Great Sand Dunes National Park and Preserve, and an additional 6 soundings were made near Hansen Bluff on the eastern edge of the Alamosa National Wildlife Refuge. The blue clay is a significant hydrologic feature in the area that separates an unconfined surface aquifer from a deeper confined aquifer. Knowledge of its location is important to regional hydrological models. Previous analysis of well logs has shown that the blue clay has a resistivity of 10 ohm-meters or less, which is in contrast to the higher resistivity of sand, gravel, and other clay units found in the area, making it a very good target for TEM soundings. The top of the blue clay was found to have considerable relief, suggesting the possibility of deformation of the clay during or after deposition. Because of rift activity, deformation is to be expected. Of the TEM profiles made across faults identified by aeromagnetic data, some showed resistivity variations and (or) subsurface elevation relief of resistivity units, suggestive of faulting. Such patterns were not associated with all suspected faults. The Hansen Bluff profile showed variations in resistivity and depth to conductor that coincide with a scarp between the highlands to the east and the floodplain of the Rio Grande to the west.

An Outbreak of Carbon Monoxide Poisoning in Yamagata Prefecture Following the Great East Japan Earthquake

Directory of Open Access Journals (Sweden)

Ken Iseki

2013-06-01

Full Text Available Background: In the aftermath of the Great East Japan Earthquake, most of the areas in Yamagata prefecture experienced a serious power failure lasting for approximately 24 hours. A number of households were subsequently poisoned with carbon monoxide (CO due to various causes. In this study, we conducted a survey of CO poisoning during the disaster. Methods: A questionnaire regarding CO poisoning associated with the disaster was sent to 37 emergency hospitals in Yamagata prefecture. Results: A total of 51 patients were treated for unintentional CO poisoning in 7 hospitals (hyperbaric oxygen chambers were present in 3 of the hospitals. The patients (18 men, 33 women ranged in age from 0 to 90 years. The source of CO exposure was charcoal briquettes (23 cases; 45%, gasoline-powered electric generators (18 cases; 35%, electric generators together with oil stoves (8 cases; 16%, oil stoves (1 cases; 2%, and automobile exhaust (1 cases; 2%. Blood carboxyhemoglobin levels ranged from 0.5% to 41.6% in 49 cases. Of these, 41 patients were treated by normobaric oxygen therapy, while one was intubated for artificial respiration. Additionally, 5 patients (10% were treated by hyperbaric oxygen therapy, and 3 patients (6% experienced delayed neuropsychiatric sequelae. Conclusion: CO sources included gasoline-powered electric generators and charcoal briquettes during the disaster. Storm-related CO poisoning is well recognized as a disaster-associated accident in the United States, but not in Japan. We emphasize that public education is needed to make people aware of the dangers of CO poisoning after a disaster. In addition, a pulse CO-oximeter should be set up in hospitals.  

A preliminary research of characteristic of selected frequency luminescence for debris flow in Jiangjiagou valley

International Nuclear Information System (INIS)

Liu Zhaowen; Wei Mingjian; Li Dongxu; Pan Baolin; Ge Yonggang

2009-01-01

Four debris flow samples were separated from Nidepin, Duozhao and Dawazigou valleys in Jiangjiagou valley area, Yunnan province. They were measured with BG2003 luminescence spectrograph. The characteristic spectra of the selected frequency luminescence of samples from the different locations were obtained. The wave length of emission photons from samples of Dawazigou valley and Jiangjia valley are 300, 310, 320, 400 and 460 nm when it was using blue light (488)nm excited. When the green light (532 nm) has been used to excited, the wave length of emission photons from samples of Dawazigou valley and Duozhao valley are similar high at 310 and 320 nm. Furthermore, using the green light excited the samples from desert sand at the same lab condition; the number of absorbed photons of samples from desert sand is much higher than from debris flow. (authors)

40 CFR 81.48 - Champlain Valley Interstate Air Quality Control Region.

Science.gov (United States)

2010-07-01

... Quality Control Region. 81.48 Section 81.48 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.48 Champlain Valley Interstate Air Quality Control Region. The Champlain Valley Interstate Air Quality Control Region (Vermont-New York) has been revised to consist of the...

Silicon Valley: Planet Startup : Disruptive Innovation, Passionate Entrepreneurship & High-tech Startups

NARCIS (Netherlands)

dr. A. Maas; Dr. P. Ester

2016-01-01

For decades now, Silicon Valley has been the home of the future. It's the birthplace of the world's most successful high-tech companies-including Apple, Yahoo, Google, Facebook, Twitter, and many more. So what's the secret? What is it about Silicon Valley that fosters entrepreneurship and

Ground-water flow and quality, and geochemical processes, in Indian Wells Valley, Kern, Inyo, and San Bernardino counties, California, 1987-88

Science.gov (United States)

Berenbrock, Charles; Schroeder, R.A.

1994-01-01

An existing water-quality data base for the 300- square-mile Indian Wells Valley was updated by means of chemical and isotopic analysis of ground water. The wide range in measured concentrations of major ions and of minor constituents such as fluoride, borate, nitrate, manganese, and iron is attributed to geochemical reactions within lacustrine deposits of the valley floor. These reactions include sulfate reduction accompanied by generation of alkalinity, precipitation of carbonates, exchange of aqueous alkaline-earth ions for sodium on clays, and dissolution of evaporite minerals. Differences in timing and location of recharge, which originates primarily in the Sierra Nevada to the west, and evapotranspiration from a shallow water table on the valley floor result in a wide range in ratios of stable hydrogen and oxygen isotopes. As ground water moves from alluvium into lustrine deposits of the ancestral China Lake, dissolved-solids concen- trations increase from about 200 to more than 1,000 milligrams per liter; further large increases to several thousand milligrams per liter occur beneath the China Lake playa. Historical data show an increase during the past 20 years in dissolved- solids concentration in several wells in the principal pumping areas at Ridgecrest and between Ridgecrest and Inyokern. The increase apparently is caused by induced flow of saline ground water from nearby China, Mirror, and Satellite Lakes. A simplified advective-transport model calculates ground-water travel times between parts of the valley of at least several thousand years, indi- cating the presence of old ground water. A local ground-water line and an evaporation line estimated using isotopic data from the China Lake area inter- sect at a delta-deuterium value of about -125 permil. This indicates that late Pleistocene recharge was 15 to 35 permil more negative than current recharge.

78 FR 59840 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

Science.gov (United States)

2013-09-30

...] Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management District... of plan. * * * * * (c) * * * (428) * * * (i) * * * (B) Antelope Valley Air Quality Management...) * * * (i) * * * (B) Antelope Valley Air Quality Management District. (1) Rule 431.1, ``Sulfur Content of...

78 FR 45114 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

Science.gov (United States)

2013-07-26

... the California State Implementation Plan, Antelope Valley Air Quality Management District AGENCY... the Antelope Valley Air Quality Management District (AVAQMD) portion of the California State... for the South Coast Air Quality Management District (SCAQMD). The Antelope Valley Air Pollution...

Organic biomarkers to describe the major carbon inputs and cycling of organic matter in the central Great Barrier Reef region

Science.gov (United States)

Burns, Kathryn; Brinkman, Diane

2011-06-01

Controversy surrounds the sources and transport of land derived pollutants in the Great Barrier Reef ecosystem because there is insufficient knowledge of the mechanism of movement of organic contaminants and the cycling of organic matter in this dynamic system. Thus a sediment and sediment trap study was used to describe the composition of resuspended and surface sediments in the south central Great Barrier Reef and its lagoon. This region is characterised by strong tides (6-8 m at Mackay) and trade winds regularly about 15-20 knots. A series of organic biomarkers detailed the cyclical processes of sediment resuspension, recolonising with marine algae and bacteria, packaging into zooplankton faecal pellets and resettlement to sediments where the organics undergo further diagenesis. With each cycle the inshore sediments are diluted with CaCO 3 reef sediments and moved further offshore with the strong ebb tide currents. This results in transport of land derived materials offshore and little storage of organic materials in the lagoon or reef sediments. These processes were detailed by inorganic measurements such as %CaCO 3 and Al/Ca ratios, and by the compositions of hydrocarbon, sterol, alcohol, and fatty acid lipid fractions. Persistent contaminants such as coal dust from a coastal loading facility can be detected in high concentration inshore and decreasing out to the shelf break at 180 m approximately 40 nautical miles offshore. The normal processes would likely be amplified during cyclonic and other storms. The lipids show the sources of carbon to include diatoms and other phytoplankton, creanaerchaeota, sulfate reducing and other bacteria, land plants including mangrove leaves, plus coal dust and other petroleum contaminants.

Long Valley Caldera-Mammoth Mountain unrest: The knowns and unknowns

Science.gov (United States)

Hill, David P.

2017-01-01

This perspective is based largely on my study of the Long Valley Caldera (California, USA) over the past 40 years. Here, I’ll examine the “knowns” and the “known unknowns” of the complex tectonic–magmatic system of the Long Valley Caldera volcanic complex. I will also offer a few brief thoughts on the “unknown unknowns” of this system.

Geological and seismic evaluation of a Lower Mannville valley system; Alderson Prospect, Rolling Hills, southeastern Alberta

Energy Technology Data Exchange (ETDEWEB)

Hopkins, J.C.; Lawton, D.C.; Gunn, J.D.

1987-09-01

A Lower Mannville valley complex cutting into Jurassic and Mississippian strata in southeastern Alberta was identified on a conventional seismic section. The valley was drilled and a twenty metre core of muddy sandstone was recovered from the target interval. Oil staining was visible within the core but tests showed only muddy water. In contrast, thin sands adjacent to the channel tested up to 300 m/sup 3//day gas and 800 m oil. Sediments adjacent to the valley are interpreted as contemporaneous levee splay deposits of a channel that occupied the valley, whereas the muddy sandstones within the channel represent either a fine grained point bar, or an abandoned channel-fill deposit. In the latter case, coarse grained, sandy, point bar deposits can be expected to occur elsewhere in the channel system. Oil is trapped in crevasse splay deposits draped over a local Mississippian high, but not in the valley because of poor reservoir quality of the channel sandstone. The internal geometry of the valley fill cannot be resolved directly from the seismic data because of the small size of the channel. However, the geometry of reflections from sediments directly above the valley shows variation in the fill and implies that, at the test location, the valley fill is an abandoned channel deposit. It is proposed here that reflection geometry above Lower Mannville valleys can provide a means of determining the type of valley fill. 11 figs., 1 tab., 29 illus.

Nanoscale Carbon Greatly Enhances Mobility of a Highly Viscous Ionic Liquid

DEFF Research Database (Denmark)

Chaban, V. V.; Prezhdo, O. V.

2014-01-01

liquids (ILs) and apolar carbon nanotubes (CNTs) are disparate objects; nevertheless, their interaction leads to spontaneous CNT filling with ILs. Moreover, ionic diffusion of highly viscous ILs can increase 5-fold inside CNTs, approaching that of molecular liquids, even though the confined IL phase still......The ability to encapsulate molecules is one of the outstanding features of nanotubes. The encapsulation alters physical and chemical properties of both nanotubes and guest species. The latter normally form a separate phase, exhibiting drastically different behavior compared to the bulk. Ionic...

Interaction Induced Quantum Valley Hall Effect in Graphene

Directory of Open Access Journals (Sweden)

E. C. Marino

2015-03-01

Full Text Available We use pseudo-quantum electrodynamics in order to describe the full electromagnetic interaction of the p electrons in graphene in a consistent 2D formulation. We first consider the effect of this interaction in the vacuum polarization tensor or, equivalently, in the current correlator. This allows us to obtain the T→0 conductivity after a smooth zero-frequency limit is taken in Kubo’s formula. Thereby, we obtain the usual expression for the minimal conductivity plus corrections due to the interaction that bring it closer to the experimental value. We then predict the onset of an interaction-driven spontaneous quantum valley Hall effect below an activation temperature of the order of 2 K. The transverse (Hall valley conductivity is evaluated exactly and shown to coincide with the one in the usual quantum Hall effect. Finally, by considering the effects of pseudo-quantum electrodynamics, we show that the electron self-energy is such that a set of P- and T-symmetric gapped electron energy eigenstates are dynamically generated, in association with the quantum valley Hall effect.

Hydrogeology and water quality of the Pepacton Reservoir Watershed in southeastern New York. Part 4. Quantity and quality of ground-water and tributary contributions to stream base flow in selected main-valley reaches

Science.gov (United States)

Heisig, Paul M.

2004-01-01

constituents such as nutrients.The total gain in streamflow from the upper end to the lower end of each valley reach was positively correlated with the annual-runoff volume calculated for the drainage area of the reach. This correlation was not greatly affected by the proportions of ground-water and tributary contributions, except at two reaches that lost much of their tributary flow after the July survey. In these reaches, the gain in total streamflow showed a negative departure from this correlation.Calculated ground-water discharge exceeded the total tributary inflow in each valley reach in both surveys. Groundwater discharge, as a percentage of streamflow gain, was greatest among reaches in wide valleys (about 1,000-ft wide valley floors) that contain permeable valley fill because tributary flows were seasonally diminished or absent as a result of streambed infiltration. Tributary inflows, as a percentage of streamflow gain, were highest in reaches of narrow valleys (200-500-ft wide valley floors) with little valley fill and high annual runoff.Stream-water and ground-water quality were characterized by major-ion type as either (1) naturally occurring water types, relatively unaffected by road salt, or (2) road-salt-affected water types having elevated concentrations of chloride and sodium. The naturally occurring waters were typically the calcium-bicarbonate type, but some contained magnesium and (or) sulfate as secondary ions. Magnesium concentration in base flow is probably related to the amount of till and its carbonate content, or to the amount of lime used on cultivated fields within a drainage area. Sulfate was a defining ion only in dilute waters (with short or unreactive flow paths) with low concentrations of bicarbonate. Nearly all tributary waters were classified as naturally occurring water types.Ground-water discharge from nearly all valley reaches that contain State or county highways had elevated concentrations of chloride and sodsodium. The mean chloride

Variability of Black Carbon and Ultrafine Particle Concentration on Urban Bike Routes in a Mid-Sized City in the Po Valley (Northern Italy

Directory of Open Access Journals (Sweden)

Giovanni Lonati

2017-02-01

Full Text Available Cyclists might experience increased air pollution exposure, due to the proximity to traffic, and higher intake, due to their active travel mode and higher ventilation. Several local factors, like meteorology, road and traffic features, and bike lanes features, affect cyclists’ exposure to traffic-related pollutants. This paper investigates the concentration levels and the effect of the features of the bike lanes on cyclists’ exposure to airborne ultrafine particulate matter (UFP and black carbon (BC in the mid-sized city of Piacenza, located in the middle of the Po Valley, Northern Italy. Monitoring campaigns were performed by means of portable instruments along different urban bike routes with bike lanes, characterized by different distances from the traffic source (on-road cycle lane, separated cycle lane, green cycle path, during morning (9:00 am–10:00 am and evening (17:30 pm–18:30 pm workday rush hours in both cold and warm seasons. The proximity to traffic significantly affected cyclists’ exposure to UFP and BC: exposure concentrations measured for the separated lane and for the green path were 1–2 times and 2–4 times lower than for the on-road lane. Concurrent measurements showed that exposure concentrations to PM10, PM2.5, and PM1 were not influenced by traffic proximity, without any significant variation between on-road cycle lane, separated lane, or green cycle path. Thus, for the location of this study PM mass-based metrics were not able to capture local scale concentration gradients in the urban area as a consequence of the rather high urban and regional background that hides the contribution of local scale sources, such as road traffic. The impact of route choice on cyclists’ exposure to UFPs and BC during commuting trips back and forth from a residential area to the train station has been also estimated through a probabilistic approach through an iterative Monte Carlo technique, based on the measured data. Compared

The use of antigen ELISA to monitor the effectiveness of a tsetse control campaign in the upper Didessa valley, Western Ethiopia

International Nuclear Information System (INIS)

Tewelde, N.; Kebede, A.; Tsegaye, A.

1997-01-01

Blood and serum samples were collected from a tsetse free zone in the central highlands of Ethiopia. The samples were collected to determine the specificity and establish percentage positivity cut-off points of the antigen ELISA. Blood samples collected from these areas were negative for trypanosomosis using Standard Trypanosome Detection Methods (STDM). Ag-ELISA, in contrast, detected circulating trypanosomal antigens in 7.6% of the serum samples collected. Similarly, samples were collected from a tsetse infested zone in the upper Didessa valley, western Ethiopia, to assess the sensitivity of the Ag-ELISA. STDM detected trypanosomal infections in the range of 15.8 and 16.7% of blood samples from this zone. On the other hand, Ag-ELISA, indicated the presence of circulating trypanosomal antigens in 38.6% of serum samples tested. Moreover, Ag-ELISA was used to monitor the effectiveness of a tsetse control campaign in the upper Didessa valley. There were great differences in the prevalence rates of trypanosomosis, as revealed by the STDM and Ag-ELISA, between the tsetse controlled and tsetse infested zones of the upper Didessa valley. Generally, the Ag-ELISA revealed the presence of circulating trypanosomal antigens in only 43.7% of patent infections. Nevertheless, the test detected 318 more cases which were not diagnosed by any one of the STDM used. More interestingly, Ag-ELISA indicated the widespread presence of T. brucei in the cattle sampled in all zones. (author). 11 refs, 4 tabs

The use of antigen ELISA to monitor the effectiveness of a tsetse control campaign in the upper Didessa valley, Western Ethiopia

Energy Technology Data Exchange (ETDEWEB)

Tewelde, N; Kebede, A; Tsegaye, A [National Tsetse and Trypanosomiasis Investigation and Control Centre (NTTICC), Bedelle (Ethiopia)

1997-02-01

Blood and serum samples were collected from a tsetse free zone in the central highlands of Ethiopia. The samples were collected to determine the specificity and establish percentage positivity cut-off points of the antigen ELISA. Blood samples collected from these areas were negative for trypanosomosis using Standard Trypanosome Detection Methods (STDM). Ag-ELISA, in contrast, detected circulating trypanosomal antigens in 7.6% of the serum samples collected. Similarly, samples were collected from a tsetse infested zone in the upper Didessa valley, western Ethiopia, to assess the sensitivity of the Ag-ELISA. STDM detected trypanosomal infections in the range of 15.8 and 16.7% of blood samples from this zone. On the other hand, Ag-ELISA, indicated the presence of circulating trypanosomal antigens in 38.6% of serum samples tested. Moreover, Ag-ELISA was used to monitor the effectiveness of a tsetse control campaign in the upper Didessa valley. There were great differences in the prevalence rates of trypanosomosis, as revealed by the STDM and Ag-ELISA, between the tsetse controlled and tsetse infested zones of the upper Didessa valley. Generally, the Ag-ELISA revealed the presence of circulating trypanosomal antigens in only 43.7% of patent infections. Nevertheless, the test detected 318 more cases which were not diagnosed by any one of the STDM used. More interestingly, Ag-ELISA indicated the widespread presence of T. brucei in the cattle sampled in all zones. (author). 11 refs, 4 tabs.

Topological induced valley polarization in bilayer graphene/Boron Nitride

Science.gov (United States)

Basile, Leonardo; Idrobo, Juan C.

2015-03-01

Novel electronic devices relay in our ability to control internal quantum degrees of freedom of the electron e.g., its spin. The valley number degree of freedom is a pseudospin that labels degenerate eigenstates at local maximum/minimum on the valence/conduction band. Valley polarization, that is, selective electronic localization in a momentum valley and its manipulation can be achieved by means of circular polarized light (CPL) in a system with strong spin-orbit coupling (SOC). In this talk, we will show theoretically that despite the fact that neither graphene or BN have a strong SOC, a bilayer of graphene on BN oriented at a twist angle has different absorption for right- and left- CPL. This induced polarization occurs due to band folding of the electronic bands, i.e., it has a topological origin. This research was supported EPN multidisciplinary grant and by DOE SUFD MSED.

Resonant tunneling spectroscopy of valley eigenstates on a donor-quantum dot coupled system

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, T., E-mail: t.kobayashi@unsw.edu.au; Heijden, J. van der; House, M. G.; Hile, S. J.; Asshoff, P.; Simmons, M. Y.; Rogge, S. [Centre for Quantum Computation and Communication Technology, University of New South Wales, Sydney 2052 New South Wales (Australia); Gonzalez-Zalba, M. F. [Hitachi Cambridge Laboratory, J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Vinet, M. [Université Grenoble-Alpes and CEA, LETI, MINATEC, 38000 Grenoble (France)

2016-04-11

We report on electronic transport measurements through a silicon double quantum dot consisting of a donor and a quantum dot. Transport spectra show resonant tunneling peaks involving different valley states, which illustrate the valley splitting in a quantum dot on a Si/SiO{sub 2} interface. The detailed gate bias dependence of double dot transport allows a first direct observation of the valley splitting in the quantum dot, which is controllable between 160 and 240 μeV with an electric field dependence 1.2 ± 0.2 meV/(MV/m). A large valley splitting is an essential requirement for implementing a physical electron spin qubit in a silicon quantum dot.

Architecture and evolution of an Early Permian carbonate complex on a tectonically active island in east-central California

Science.gov (United States)

Stevens, Calvin H.; Magginetti, Robert T.; Stone, Paul

2015-01-01

The newly named Upland Valley Limestone represents a carbonate complex that developed on and adjacent to a tectonically active island in east-central California during a brief interval of Early Permian (late Artinskian) time. This lithologically unique, relatively thin limestone unit lies within a thick sequence of predominantly siliciclastic rocks and is characterized by its high concentration of crinoidal debris, pronounced lateral changes in thickness and lithofacies, and a largely endemic fusulinid fauna. Most outcrops represent a carbonate platform and debris derived from it and shed downslope, but another group of outcrops represents one or possibly more isolated carbonate buildups that developed offshore from the platform. Tectonic activity in the area occurred before, probably during, and after deposition of this short-lived carbonate complex.

Carbon nanomaterials for high-performance supercapacitors

OpenAIRE

Tao Chen; Liming Dai

2013-01-01

Owing to their high energy density and power density, supercapacitors exhibit great potential as high-performance energy sources for advanced technologies. Recently, carbon nanomaterials (especially, carbon nanotubes and graphene) have been widely investigated as effective electrodes in supercapacitors due to their high specific surface area, excellent electrical and mechanical properties. This article summarizes the recent progresses on the development of high-performance supercapacitors bas...

76 FR 38572 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

Science.gov (United States)

2011-07-01

... the California State Implementation Plan, Antelope Valley Air Quality Management District AGENCY... approve revisions to the Antelope Valley Air Quality Management District (AVAQMD) portion of the... approving with the dates that they were adopted by the Antelope Valley Air Quality Management District...

Mapping Ecosystem Services in the Jordan Valley, Jordan

Science.gov (United States)

Luz, Ana; Marques, Ana; Ribeiro, Inês; Alho, Maria; Catarina Afonso, Ana; Almeida, Erika; Branquinho, Cristina; Talozi, Samer; Pinho, Pedro

2016-04-01

In the last decade researchers started using ecosystem services as a new framework to understand the relationships between environment and society. Habitat quality and water quality are related with ecosystem services regulation and maintenance, or even provision. According to the Common International Classification of Ecosystem Services (CICES) both habitat quality and water quality are associated with lifecycle maintenance, habitat and gene pool protection, and water conditions, among others. As there is increased pressure on habitats and rivers especially for agricultural development, mapping and evaluating habitat and water quality has important implications for resource management and conservation, as well as for rural development. Here, we model and map habitat and water quality in the Jordan Valley, Jordan. In this study, we aim to identify and analyse ecosystem services both through 1) habitat quality and 2) water quality modelling using InVest, an integrated valuation of ecosystem services and tradeoffs. The data used in this study mainly includes the LULC, Jordan River watershed and main threats and pollutants in the study area, such as agriculture, industry, fish farms and urbanization. Results suggest a higher pressure on natural habitats in the Northern region of the Jordan Valley, where industry is dominant. Agriculture is present along the Jordan Valley and limits the few natural forested areas. Further, water pollution is mainly concentrated in disposal sites due to the low flow of the Jordan River. Our results can help to identify areas where natural resources and water resource management is most needed in the Jordan Valley. Acknowledgements: Transbasin FP7 project

Controls on valley spacing in landscapes subject to rapid base-level fall

Science.gov (United States)

McGuire, Luke; Pelletier, John D.

2015-01-01

What controls the architecture of drainage networks is a fundamental question in geomorphology. Recent work has elucidated the mechanisms of drainage network development in steadily uplifting landscapes, but the controls on drainage-network morphology in transient landscapes are relatively unknown. In this paper we exploit natural experiments in drainage network development in incised Plio-Quaternary alluvial fan surfaces in order to understand and quantify drainage network development in highly transient landscapes, i.e. initially unincised low-relief surfaces that experience a pulse of rapid base-level drop followed by relative base-level stasis. Parallel drainage networks formed on incised alluvial-fan surfaces tend to have a drainage spacing that is approximately proportional to the magnitude of the base-level drop. Numerical experiments suggest that this observed relationship between the magnitude of base-level drop and mean drainage spacing is the result of feedbacks among the depth of valley incision, mass wasting and nonlinear increases in the rate of colluvial sediment transport with slope gradient on steep valley side slopes that lead to increasingly wide valleys in cases of larger base-level drop. We identify a threshold magnitude of base-level drop above which side slopes lengthen sufficiently to promote increases in contributing area and fluvial incision rates that lead to branching and encourage drainage networks to transition from systems of first-order valleys to systems of higher-order, branching valleys. The headward growth of these branching tributaries prevents the development of adjacent, ephemeral drainages and promotes a higher mean valley spacing relative to cases in which tributaries do not form. Model results offer additional insights into the response of initially unincised landscapes to rapid base-level drop and provide a preliminary basis for understanding how varying amounts of base-level change influence valley network morphology.

Spin- and valley-polarized one-way Klein tunneling in photonic topological insulators

Science.gov (United States)

Slobozhanyuk, Alexey

2018-01-01

Recent advances in condensed matter physics have shown that the spin degree of freedom of electrons can be efficiently exploited in the emergent field of spintronics, offering unique opportunities for efficient data transfer, computing, and storage (1–3). These concepts have been inspiring analogous approaches in photonics, where the manipulation of an artificially engineered pseudospin degree of freedom can be enabled by synthetic gauge fields acting on light (4–6). The ability to control these degrees of freedom significantly expands the landscape of available optical responses, which may revolutionize optical computing and the basic means of controlling light in photonic devices across the entire electromagnetic spectrum. We demonstrate a new class of photonic systems, described by effective Hamiltonians in which competing synthetic gauge fields, engineered in pseudospin, chirality/sublattice, and valley subspaces, result in bandgap opening at one of the valleys, whereas the other valley exhibits Dirac-like conical dispersion. We show that this effective response has marked implications on photon transport, among which are as follows: (i) a robust pseudospin- and valley-polarized one-way Klein tunneling and (ii) topological edge states that coexist within the Dirac continuum for opposite valley and pseudospin polarizations. These phenomena offer new ways to control light in photonics, in particular, for on-chip optical isolation, filtering, and wave-division multiplexing by selective action on their pseudospin and valley degrees of freedom. PMID:29756032

Valley dynamics of intravalley and intervalley multiexcitonic states in monolayer WS2

Science.gov (United States)

Fu, Jiyong; Bezerra, Andre; Qu, Fanyao

2018-03-01

We present a comprehensive model comprising of a complete set of rate equations, which account for charge transfer among multiexcitonic channels including excitons, trions, and biexcitons, to investigate valley (locked with spin) dynamics in monolayer WS2. The steady-state photoluminescence (PL) spectra, underlying the laser power dependence of excitonic populations, are also determined. Our computed PL for all excitonic states agrees with the experimental data of Paradisanos et al. [Appl. Phys. Lett. 110, 193102 (2017), 10.1063/1.4983285]. We find that the relative weight of PL, stemmed from different excitonic channels, strongly depends on the laser power even under dynamical conditions. Remarkably, the biexciton channel, having the weakest PL intensity at low laser powers, tends to prevail in PL over other excitonic states as the power strengthens. In addition, by accounting for intervalley scatterings, which enable transfer of excitonic states from one valley to the other, we determine the valley polarization, which strongly depends on intervalley scatterings and the exciton generation rates in the two valleys. On the other hand, the valley polarization for all excitonic channels is found almost independent of the laser power, consistent with experimental measurements as well. Finally, the valley dynamics involving both intra- and intervalley trions is discussed. Our model and numerical outcome should be beneficial to experiments especially featuring the interplay of multiexcitonic channels in, e.g., elucidating experimental data, estimating central excitonic quantities including recombination times and transition rates, and in widening possible new experimental scopes.

The browse value of the Eastern Cape valley bushveld. | A.J. ...

African Journals Online (AJOL)

The feeding value of the Eastern Cape Valley Bushveld in terms of crude protein, digestible dry matter, digestible energy and metabolic energy, as selected by oesophageal fistulated Boer- and Angora goats was determined. Results show that the Valley Bushveld maintains a high feed value throughout the year. The high ...

78 FR 57629 - Eagle Valley Clean Energy, LLC; Notice of Filing

Science.gov (United States)

2013-09-19

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket Nos. EL13-87-000; QF13-658-000] Eagle Valley Clean Energy, LLC; Notice of Filing Take notice that on September 9, 2013, Eagle Valley Clean Energy, LLC filed Form 556 and a petition for certification as a qualifying small power production...

Many-body effects in valleytronics: direct measurement of valley lifetimes in single-layer MoS2.